DESIZING OF SYNTHETIC SIZES

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					                                DESIZING OF SYNTHETIC SIZES


                                             A. RONCOLI
                                     G. Bozzetto S.p.A., ITALY


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                                       Copied on August 12, 2004



INTRODUCTION

The desizing operation is essential for textile finishing.

This handbook is our practical contribution to operators in the sector.

As we all know, ,insufficient, non-uniform removal of size, which protected the warp during
weaving, produces a fabric with a “ hard papery” handle, or causes haloes and stains
compromising its appearance and subsequent use.

Knowledge of the chemical / physical behaviour as sizing products is certainly a key factor in
fully eliminating them. As work requirements often make it necessary to treat fabrics with
different types of size on the same machine and in the same bath, we think an overall
assessment is useful. We shall then include indications on eliminating individual sizing products in
the specific technical instructions.

A Reaction of sizes to different agents

 Action of surfactants The specific action of surfactants is to endow baths with wetting,
emulsifying and detergent capabilities. They therefore have a favourable effect on removing
both size and finishing oils. All surfactants lower surface tension of water and thus accelerate
bath-into-fibre penetration time (this is very important especially for desizing in continuous
systems).

 Some surfactants have also a certain ''solubilising'' power on resins used for sizing. It is,
therefore, essential that, when selecting which surfactant to use, one should bear in mind all
factors that help to improve and speed up desizing.

 In particular, the surfactant's stability with respect to pH and to the electrolytes in the desizing
bath must be evaluated, as well as its suitability in connection with the characteristics of the
system , in which it is to be used, in order to prevent unwanted foam formation.

The products we suggest case by case, and which can be identified among various brands
(Biomegapal-DS-Fimbil-ldrosolvan-Laif-Ottin), satisfy all specific requirements. In most cases,
these products are non-ionic composites or preparations containing anionic and non-ionic
detergents. Cationic surfactants are not taken into consideration because they would produce
incompatibility effects on all resins containing an anionic charge.

Use of detergent containing solvents is particularly recommended for very dirty or highly
''charged'' fabrics in ensimages that are difficult to emulsify.

 Action of sequestering agents In hard water, some sizes tend to become insoluble and thus
precipitate into the bath. Although using purified water, a gradual increase in hardness can be
noted on continuous lines due to the fabric (fabrics mixed with cellulose fibres) releasing
calcareous salts. As a result a specific sequestering agent must be added to the recipe, which
also has a strong dispersing and anti-flocculating power. Of the various possibilities offered on
the market, we think that phosphonates are the family most closely satisfying the requirements
of the desizing process. Bozzetto sequestering agents are easily identified by their commercial
name: Sequion.

Action of alkali Alkali can influence the desizing process either positively or negatively,
according

to the chemical composition of the size in the warp.

 To give an example, acrylic sizes (ammonia salts) necessarily require caustic alkali to ensure
they dissolve completely, whereas sizes with a soluble polyester base become insoluble and
precipitate under the same conditions.

The most commonly used alkali are Solvay soda (sodium carbonate) and caustic soda.

We shall therefore provide -case by case -precise indications on the type and suitable
concentration of alkali to use according to type of size, fibre and desizing system.

Action of acids Similarly to alkali, behaviour varies according to sizes in the case of acids too.
Some of them are not dissolved, others are easily eliminated in dyeing pH conditions.

 Action of chlorinated solvents No kind                of   size   is   soluble   in   trichloroethylene,
perchloroethylene or fluorochlorine derivatives.

 Action of oxidants The use of moderate quantities of hydrogen peroxide and sodium
hypochlorite in desizing baths does not prevent acrylic and polyester resins from becoming
soluble, but neither does it contribute to accelerate their dissolution time. The use of these
substances is, in any event, recommended if there are mould stains on the fabric. The oxidant
most suitable for direct use in the desizing bath is hydrogen peroxide, since it acts at high
temperatures and, therefore, enables both mould to degrade and sizes to rapidly solubilize. In
case of very large, widespread mould stains, long treatment time is essential and, as a result, we
recommend discontinuous desizing processes (flow-jigger-etc.).

B Factors influencing desizing

Many factors influence desizing -we mention the most important ones below:

composition of baths: pH/ concentration and chemical[ nature of assistants 1 presence of
electrolytes (salts -hardness)
We shall provide, in the following chapters, specific indications on selecting assistants aııd on the
most suitable conditions to adopt, depending on type of size and fibre used.

The presence of calcium and magnesium salts, or of any highly electrolytic substance can cause
serious insolubilisation problems to various types of size:

this is why we recommend always using purified water (with hardness below 1 o dH) for both 1
desizing and washing (at Ieast for the first rinse).

Desizing temperature The best results are obtained by maintaining desizing bath temperature
in the range of 85°C to 95°C, except when treating acetate rayon and mixed wool fabrics, which
only in certain cases support these temperatures (see chapters III and V.7).

From our experience, we consider that treatments at higher temperatures (under pressure) do
not help in btaining better results in terms of size removal.

 Operating at temperatures below 85°C size film dissolution times quickly increase and, therefore,
treatment time must be prolonged to maintain the same desizing efficiency.

To clarify matters further, the following table shows the relationship between temperature and
the dissolution time of a film of size in baths prepared either with or without a specific surfactant
/emulsifier.




  Temperature             Dissolution time                 Dissolution time with
      °C                                                    specific surfactant
                        without surfactant
                      PES size       Acrylic size       PES size        Acrylic size
       30              >60`             >60`             >60`             >60`
       45               60`              60`              40`               40`
       60               30`              30`              10`               10`
       75               3`                3`              1`                 1`
       90              30``             30``             20``              20``




Remember that in order to obtain uniform desizing on continuous lines, temperature fluctuations
must be avoided.

Contact time between desizing bath and sized fabric Time of contact between bath and fibre is
essential to establish whether a certain desizing treatment is possible on a system and prepare
the best recipes according to the effective characteristics noted.

 An ''ideal'' minimum contact time between bath and fibre that can be used as a reference cannot
be defined, due to the diverse mechanical concepts of different systems. However, we can
provide some indications acquired through experience.
 a) Desizing on continuous lines: we recommend a minimum presence time of 60'' for the
fabric in the desizing bath, divided into at least two distinct units, and a further 60'' washing time
divided into two or more units.

b) Desizing in jigger: 4 passages with desizing bath, drain bath, 3 washing passages with
water at 85-90°C, drain bath, cold washing by continuous drainage from overflow.

c) Desizing in Overflow-Jet-Beam: 30' with desizing bath, drain bath, 1 0-15' washing at 85-
90oC, drain bath , final cold washing.

It is clear that the more accurate and prolonged the desizing and washing treatments, the better
the final result. For very dense or ''special'' articles (microfilaments-textured), a double desizing
treatment may be necessary, especially in systems with Iimited mechanical action or with a very
Iimited liquor ratio.

Mechanical action of the system In general, the stronger the mechanical action, the more
efficient the size removal. The mechanical action is provided by squeezing, bath injectors, bath
circulation speed in the bowls and fabric transit speed.

 Weave of fabric Highly compact synthetic fabrics hinder bath penetration to a greater extent,
due to the considerable swelling of the fibres (especially at temperatures above 1 OO°C), which
causes further compacting of the structure.




Sizing products reduce bath penetration speed and thus desizing. It is very important to reach in
rinsing the same degree of swelling obtained during desizing. This is to allow the bath to remove
resin residues which had penetrated deep into the fibre (substantial swelling of the fibre actually
allows sizing products to be more easily eliminated, but also enables them to penetrate inside the
fibre to a greater degree).

Goods-liquor ratio In any type of system, and especially in discontinuous systems, size
elimination is encouraged by a high liquor ratio. In view,of this, desizing in jigger is certainly less
efficient and sure, partly due to the system's limited mechanical action.

Final washing All too often the importance of washing after desizing is underestimated.
Remember that size residues not fully removed from the fabric Iead -after thermal fixing -to
insoluble precipitates which, after dyeing, appear as haloes and stains. Furthermore, the fabric
handle becomes more or less stiff, to a degree depending on the quantity of size remaining.

 In addition to totally removing the different sizing products, the final washing must ensure that
the pH values of the fabric are uniform and as close as possible to neutral. Washing temperature
must be maintained at 80 to 90°C, at least for the first rinses.

C Type of process

Discontinuous The usual systems are used, such as:

Open width treatment = jigger -beam. Rope treatment = overflow -jet -open winch
 Semi-continuous We advise against work cycles involving padding and cold storage (pad-
batch),

as Iow temperature has no appreciable effect on the synthetic sizes.

In some cases, storage at 80 -90°C (pad-roll), with specific detergents (I DROSOLVAN) helps the
avivage oils to emulsify -the oils are more easily removed when the fabric is subsequently
washed. Storing mixed fabrics consisting of chemical and cellulose fibres is not recommended
due to possible interaction of sizes with ''the electrolytes'' in the cellulose fibres, which give rise
to the resin insolubilisation process thus increasing desizing difficulty.

Therefore the advisability of pad-batch desizing, during cold bleaching with peroxide 4>f fabrics
mixed

with cellulose, needs assessing case by case.

Continuous Continuous lines are based on a different mechanical concept, and also differ

considerably in terms of capacity, bath volumes, batch exchanges, etc.

In general, system management is particularly important, because operational uniformity is
essential

in order to prevent, by continuous bath changes, size from accumulating.

Of course saving on water and energy must not be overlooked, but this must not be to the
detriment

of the objective: good desizing results during the whole working day.

D Notes on the tables

Two tables appear at the beginning of each chapter, showing the behaviour of size films in
different treatment baths and the indicative quantities of the films according to the different sized
threads.

a) Size features To evaluate these features, the following are examined: different
temperatures,

1 pH values in both acid and alkaline fields, and water hardness.

In greater detail:

-in purified water at 20C. -50C. -90C.

-in an acid environment for acetic acid 10 ml/l (pH 3), at 90C.

-in an alkaline environment for caustic soda 36°Be 5 ml/l (pH 12), at 90C.

-in water at 30° French degrees of hardness (pH 7), at 90 C.
Size behaviour is defined as follows:

 = indicates good dissolution of size present in the specific treatment bath, at sufficiently rapid
times, ensuring good size removal when treating a sized fabric;

 = indicates complete solubility of the film if some specific conditions are observed -to be
mentioned time by time.

 = indicates difficult or partial solubility of the film.

As one may not always know what type of size is present in the warp of a fabric, we advise you
to run preliminary tests to define quality, following the procedure described in detail in chapter
VI.2.

b) Guide-lines on size quantity We shall indicate types of size and their percentages
according to the characteristics of the threads and their use on dry or water-jet Iooms. It's easy
to understand the importance of these quantitative elements in defining the best composition of
desizing baths.

CHAPTER 1

Desizing polyester fibre fabrics

I.1 Size used / I.2 Capability of sizes to be removed / I.3 Desizing fabrics containing sizes with
acrylic copolymers (ammonium salts) / I.4 Desizing fabrics containing solube polyester sizes / I.5
Desizing fabrics containing vinyl rein sizes / I.6 Single – bath desizing of acrylic – polyester –
vinyl sizes / I.7 Recovery of faulty pieces ( due to hard – papery handle or with stains caused by
poor desizing) / I.8 Oligomers

I.1 Size used

Solube polyester resins : Wisester N 530 – Wisester N 102

Modified polyester resins : PS 15207

Acrylic copolymers – Ammonium salts : Wisacril PNS – Wisacril VLS

   Fibre             Torions                      Dry looms                     Water looms

                                        Product % of dry matter on       Product % of dry matter on
                                                 the yarn                         the yarn
                With 150 ÷200               N530          2,5 ÷ 3,5
               twists/m Wisester
                 With parallel          Wisester N530         3,5 ÷ 5    Wisester N530     3÷    4
 Flat PES
                                        Wisester N102         4,5 ÷ 6    Wisester N102     4÷    5
                   Filaments                                              Wisacril PNS     4÷    5
                                           PS 15207          4,5 ÷ 5,5
                 intermingled                                             Wisacril VLS   4,5 ÷   5,5
 Textured       With 150 ÷ 200          Wisester N530         7÷9
     PES            twists / m              PS 15207           8 ÷ 10
                                          Wisester N530        6 ÷ 12
                   With parallel
                                            PS 15207           7 ÷ 12       Wisester N530      6 ÷ 10
                     filaments
                                                                             Wisacril PNS      7 ÷ 11
                   intermingled
                                                                             Wisacril VLS      8 ÷ 12




Notes The indicated percentages refer to warp only.

Size quantities are indicative and could be modified to type of thread an loom used.

I.2 Capability of sizes to be removed




                                          In Water                Acetic acid   Caustic soda
       Hardness in F           0          0      0       30           0             0
            PH                  7          7      7        7           3            12
     Temperature in C         20         50     90       90          90            90

     WISESTER N 530                                                             
     WISESTER N 102                                                             

        PS 15207                                                                
      WISACRIL PNS                                                              
      WISACRIL VLS                                                              

KEY

 : Good film dissolution

 : Reasonable film dissolution ( however, we advise you not to go below pH 4 to avoid
reducing film dissolution speed)

 : Difficult / patrial film solubility

I.3 Desizing fabrics containing sizes with acrylic copolymers (ammonium salts)

Presence of caustic alkali is recommended, as these types of size are virtually insoluble in a
neutral environment or, worse still, in an acid environment. The ideal quantity of caustic soda
depends .especially in continuous systems .on the time the fabric is present in the treatment
bath. Using a fairly high concentration of NaOH is an advantage, providing a good final washing
is possible on the machine.

Specimen recipes

I.3.1 - On discontinuous machines

a)      Jigger
1) IDROSOLVAN MX                 6-8 ml/l                  95°C/4 passages; drain bath

     Na2CO3                       2 g/l

or




1) NaOH 30%                      5 ml/l

Detergent/wetting agent                     2 – 3 ml / l            95°C/4 passages; drain bath

Sequestering/dispersing agent as necessary




2) Washing with soft water at 90°C/2-3 passages; drain bath




3) Washing with cold water and, If necessary, acid neutrolisotlon




Recommended detergents: DS 100 -IDROSOLVAN E-500 -IOROSOLVAN 725

Recommended sequestering agents: SEQUION MC 200 -SEQUION M 500

Multi-purpose product: IDROSOLVAN MX




Notes on process:

For very dense/compact (e.g. microfilament-twisted), delicate (e.g. satins) fabrics and those with
high size concentrations (e.g. textured), double desizing treatment may be necessary to fully
remove resin.
Even when using short (<1 :4) liquor ratios, double treatment is sometimes necessary. If
softened water cannot be used, demineralisation is essential, adding a sequestering agent and
alkali before Ioading the fabric in the jigger, to prevent hardness inhibiting resin solubility from
the very beginning.

In the latter case, we recommend a slightly Iower desizing temperature (85+90°C).

b)      Overflow-Jet
1) IDROSOLVAN MX                           5-7ml/l                  90°C/30'; drain bath

Na2CO3                                     2 g/l




or




1) NaOH 30%                                4 ml/l                   90°C/30'; drain bath

     Detergent/wetting agent               2 ml/l

     Sequestering/dispersing agent                   as necessary

     Crack-mark inhibitor (if necessary)   2 ml/l




2) Washing with soft water at 80°C/10'; drain bath




3) Washing with cold water and, if necessary acid neutralisation




1) NaOH 30%                                4 ml/l                   90°C/30'; drain bath

     Detergent/wetting agent               2 ml/l

     Sequestering/dispersing agent                   as necessary

     Crack-mark inhibitor (if necessary)   2 ml/l




2) Washing with soft water at 80°C/10'; drain bath




3) Washing with cold water and, if necessary acid neutralisation




Recommended detergents: IDROSOLVAN E-CO -FIMBIL HOF

Recommended sequestering agents: SEQUION MC 200 -SEQUION M 500
Recommended crack-mark inhibitors: ISOPAL A 39 -FELEN 1 00

Multi-purpose product: IDROSOLVAN MX

c)       Beam




1) IDROSOLVAN MX                         5-7 ml/l                          90°C/30'; drain bath

     Na2CO3                              2 g/1




or

1) NaOH 30%                              3 ml/l                     90°C/30'; drain bath

Detergent/wetting agent                             2 ml/l

Sequestering/dispersing agent            as necessary




2) Washing with soft water at 8O°C/10'; drain bath




3) Washing with cold water and, if necessary, acid neutralisation




Recommended detergents: IDROSOLVAN E-CO -BIOMEGAPAL VS

Recommended sequestering agents: SEQUION MC 200 -SEQUION M 500

Multi-purpose product: IDROSOLVAN MX




Notes on the process:

We advise you not to desize in the beam polyester fabrics sized with acrylic resins when purified
water cannot be used.




1.3.2 -On continuous machines
Adjust the quantity of caustic soda in the recipe according to permanence time of fabric in the
treatment bath, carefully taking into account the availability and efficiency of final washing.
Obviously, the percentage of size on the fabric and fabric characteristics (weave -number of
threads and wefts/cm) are important, and, therefore, the best running conditions for the system
must be defined time by time.




Treatment bath:




1) IDROSOLVAN MX                        10-15 ml/l                 90-95°C/ (permanence time

Na2CO3                          2 g/1                     according to system used)




Or

1) NaOH 30%                             5-15 ml/l                  90-95°C/ (permanence time

Detergent/wetting agent                          2 ml/l                   according to system
used)

Sequestering/dispersing agent           as necessary




2) Washing with soft water at 90-95°C in at Ieast 2 bowls




3) Washing with cold water and, if necessary acid neutralisation




1) NaOH 30%                             5-15 ml/l                  90-95°C/ (permanence time

Detergent/wetting agent                          2 ml/l                   according to system
used)

Sequestering/dispersing agent           as necessary
2) Washing with soft water at 90-95°C in at Ieast 2 bowls




3) Washing with cold water and, if necessary acid neutralisation




1) NaOH 30%                               5-15 ml/l                 90-95°C/ (permanence time

Detergent/wetting agent                            2 ml/l                    according to system
used)

Sequestering/dispersing agent             as necessary




2) Washing with soft water at 90-95°C in at Ieast 2 bowls




3) Washing with cold water and, if necessary acid neutralisation

Recommended detergents: DS 100 -BIOMEGAPAL VS

Recommended sequestering agents: SEQUION MC 200 -SEQUION M 500

Multi-purpose product: IDROSOLVAN MX

Notes on the process:

Partially drain off by overflow, replacing the treatment bath and washing waters.

I.4 Desizing fabrics containing soluble polyester sizes

 In recent years these polymers have been widely used for sizing polyester thread, thanks to
their properties which have led to substantial improvements in I00rn performance and output.

We should stress that, contrary to acrylic based sizing, these products do not readily support
desizing treatments with alkaline baths. pH quantity being equal, the type of alkali used,
according to its ''ionic power'', accelerates the resin insolubilisation process and, therefore, strong
alkali such as caustic soda must be strictly avoided, whereas sodium carbonate and, better still,
ammonia are more suitable. In any case, do not exceed pH 1 0.

Polyester sizes are also sensitive to electrolytes, and in particular, to calcium and magnesium
salts. To remove sizes containing soluble polyester, the following must be used:

-an anionic and/or non-ionic surfactant

.a small quantity of sodium carbonate (0.5-1 g/l maximum);
-a sequestering agent with dispersing effect, especially when using hard water.

For obvious reasons, any alkaline product or any product with strong electrolytic power should be
avoided, such as the use of EDTA-Na4 type sequestering agents.

Specimen recipes

1.4.1 -On discontinuous machines

a) Jigger




1) IDROSOLVAN MX                         6-8 ml/l                                 95°C/4
passages; drain bath




or




1) Na2CO3                                0,5 g/1                         95°C/4 passages; drain
bath

Detergent/wetting agent                             2-3 ml/l

Sequestering/dispersing agent            as necessary




2) Washing with soft water at 90°C/2-3 passages; drain bath




3) Washing with cold water and, if necessary, acid neutralisation




Recommended detergents: DS 100 -IDROSOLVAN E-500 -IDROSOVAN 725

Recommended sequestering agents: SEQUION MC 200 -SEQUION M 500

Multi-purpose product: IDROSOLVAN MX

Notes on the process:

For very dense/compact (e.g. microfilament-twisted), delicate (e.g. satins) fabrics and those with
high size concentrations (e.g. textured), double desizing treatment may be necessary to fully
remove resin.
Even when using short (<1 :4) \liquor ratios, double treatment is sometimes necessary.

If soft water cannot be used, demineralisation is essential, adding a sequestering agent and alkali
before loading the fabric in the jigger, to prevent hardness inhibiting resin solubility from the very
beginning.

In the latter case, we recommend a slightly lower desizing temperature (85-90°C).




b) Overflow-Jet




1) IDROSOLVAN MX                          4-6 ml/l                          90°C/30'; drain bath




or




1) Na2CO3                                 0,5 g/1                   90°C/30'; drain bath

     Detergent/wetting agent 2 ml/l

     Sequestering/dispersing agent                   as necessary

Crack-mark inhibitor (lf necessary) 2 ml/l




2) Washing with soft water at 80°C/10'; drain bath




3) Washing with cold water and, If necessary, acid neutralisation




Recommended detergents: IDROSOLVAN E-CO -FIMBIL HOF

Recommended sequestering agents: SEQUION MC 200 -SEQUION M 500

Recommended crack-mark inhibitors: ISOPAL A 39 -FELEN 1 00

Multi-purpose product: IDROSOLVAN MX
c) Beam




1)IDSOLVAN MX                           5-7 ml/l                         9O°C/30'; drain bath




or




1) Na2CO3                               0,5 g/l                   90°C/30'; drain bath

     Detergent/wetting agent 2 ml/l

     Sequestering/ dispersing agent                as necessary




2) Washing with soft water at 80°C/10'; drain bath




3) Washing with cold water and, if necessary, acid neutralisation




Recommended detergents: IDROSOLVAN E-CO -BIOMEGAPAL VS

Recommended sequestering agents: SEQUION MC 200 -SEQUION M 500

Multi-purpose product: IDROSOLVAN MX




Notes on the process:

We advise you not to desize in the beam polyester fabrics sized with soluble polyester resin when
purified water cannot be used.




I.4.2 -On continuous machines




Treatment bath:
1) IDSOLVAN MX                           8-10 ml/l                  90-95°C/ (permanence time

                                                                 according to system used)




or




1) Na2CO3                                0,5-1 g/l                  90-95°C/ (permanence time

     Detergent/wetting agent             2 ml/l                     according to system used)

     Sequestering/dispersing agent                as necessary




2) Washing with soft water at 9O-95°C in at least 2 bawls




3) Washing with cold water and, if necessary, acid neutralisation




I.5 Desizing fabrics containing vinyl resin sizes

This size category is much Iess used compared to acrylic and soluble polyester sizes.

However, desizing conditions are similar to those described for soluble polyester sizes.




I.6 Single-bath desizing of acrylic -polyester -vinyl sizes

The need to use a single bath for simultaneously desizing all three types of size applies in
particular to continuous machines.

This is possible by using the following specific products: Idrosolvan M 80; Idrosolvan M 90;

Idrosolvan M 450 and Idrosolvan MX.
      Typical recipes                                           Sizes
                                    Polyester                  Acrylic                Vinyl
   NaOH 30 % - 5 ml /l
                              Precipitate in the
                                                                                     Difficult
  Detergent     - 2 ml/l            bath
                                                                O.K.
                                                                                   Dissolution
 Sequestering agent – as               (x)
           req
    Na2CO3 - 0,5 g/l

   Detergent - 2 ml /l
                                      O.K.            DO not dissolve (Y)             O.K.

 Sequestering agent – as
           req
     Na2CO3 - 0,5 g/l

 IDROSOLVAN - 10 ml/l
                                      O.K.                      O.K.                  O.K.

 Sequestering agent – as
           req




If case (X) occurs, this would easily Iead to stains on the fabrics due to the precipitated polyester
sizes

re-depositing. In case (V), there would be hard -papery handles due to only partial desizing of
acrylic sizes.




Examples of single-bath desizing:




I.6. 1. On discontinuous machines




a) Jigger




1) IDROSOLVAN BRANDS                               8-10 ml/l                95°C/4 passages; drain
both

  Sequestering agent                               as necessary
  Na2CO3                                            0,5-1 g/1




2) Washing with soft water o(90°C/2-3 passages; drain bath




3) Washing with cold water and , if necessary, acid neutralisation




Recommended sequestering agents: SEQUION MC 200 -SEQUION M 500

Recommended specific product: IDROSOLVAN M 80 -IDROSOLVAN M 450 -1 DROSOLVAN MX




Notes on the process:

The indications in the notes on the process of in-jigger desizing of acrylic resins and soluble
polyesters also apply here.




b) Overflow -Jet -Beam




1) IDROSOLVAN MX                                    5-7ml/l                         90°C/30'; drain
bath

     Na2CO3




or




1) IDROSOLVAN M                           6-7ml/l                           90°C/30'; drain bath

     Sequestering agent 05 necessary

     Na2CO3                               0,5-1 g/1

     Detergent/wetting agent              2 ml/l
2) Washing with so{t water at 85°C/10'; drain bath




3) Washing with cold water and, if necessary, acid neutralisation




Recommended detergents: IDRO50LVAN E-CO -FIMBIL HOF

Recommended sequestering agents: SEQUION MC 200 -SEQUION M 500

Recommended specific product: IDROSOLVAN M 90 -IDROSOLVAN MX




I.6.2 -On continuous machines




1) IDROSOLVAN MX                         10-12 ml/l                       95°C, from 2 to 10
minutes,

   Na2CO3                                1-1,5 g/l                        depending on type of
system




or




1) IDROSOLVAN BRANDS                     8-10 ml/l                        95°C, from 2 to 10
minutes,

   Sequestering agent                    as necessary                     depending on type of
system

     Na2CO3                              1-1,5 g/1




2) Washing with soft water at 9O°C In the first rinsing bowls




3) Final washing with cold water and, If necessary, acid neutralisation
Recommended sequestering agents: SEQUION MC 200- SEQUION M 500

Recommended specific product: IDROSOLVAN M 80 -IDROSOLVAN M 450 -IDROSOLVAN MX




Notes on the process:

 The desizing bath and the rinsing bowls must be constantly reinforced to avoid dangerous size
deposits. We advise you to use ''overflows'' or even fully replace the bath if sizing products
accumulate in excessively in the bowls.




The ideal working pH value is from 9 to 10.




I.7. Recovery of faulty pieces (due to hard – papery handle or with stains caused by
poor desizing)




If resin is not fully removed during desizing, this causes the polymer to ''plasticize'' during
thermo-fixing in turn causing it to ''fuse'' with the surface layer of the polyester fibres. In this
state, the size can no Ionger be eliminated with the usual scouring/washing/desizing recipes.

The fault can be eliminated (whether it is due to polyester or acrylic size) by strong alkaline
treatment (surface decortication of polyester fibre). The following are some examples of
treatment, possible on discontinuous machines only.




a) Jigger




1) ISOPON SPO                                     7-8 ml/l                                 95°C/4-
6 passages; drain bath

  NaOH 30%                               35-40 ml/l




2) Washing with soft water at 90°C/2-3 passages; drain bath
3) Washing with cold water and add neutralisation




b) Overflow -Jet -Beam




1) ISOPON SPO                                     4-5 ml/l                                 95°C/4-
6 passages; drain bath

  NaOH 30%                               15-20 ml/l




2) Washing with soft water at 90°C/10'; drain bath




3) Washing with cold water and add neutralisation




Notes:

Please note the assistant product used, which performs ''treatment adjuster'' action.




I.8 Oligomers




The term ''oligomers'' means the complex of different by-products of low molecular weight
forming during polymerisation of diethylene glycol with terephthalic acid to obtain polyester fibre.
Oligomers can have many different structures and are classified according to the number of units
they contain. Consequently, there are monomers, dimers, linear trimers, cyclic trimers and 50 on
up to a maximum of 7-8 units. The majority of oligomers present are trimers, especially those
with a cyclic structure. Trimers cause ''interference'' during industrial treatments.

It is difficult to establish the exact concentration of these low polymers as they may be split in
different quantities in the internal and external parts of the fibre. Their average quantity can be
estimated as 1.5 to 2.5%. In practice, surface oligomers are the cause of dyeing faults.

The quantity of surface oligomers can be estimated by cold-state extraction with dioxane,
although

this evaluation does not enable one to foresee any dyeing problems.
This is because these low polymers have high thermal sensitivity causing them to migrate from
the heart of the fibre toward the surface, in particular during prolonged hot-state treatments or
also during relatively brief treatments under pressure at very high temperature.

The oligomers are partially ''filtered'' on the fabric surface and form molecular groups (deposits)
that

retain, to an anomalous degree, the different substances dispersed in the bath.

These groups are very difficult to remove with traditional washing treatments.

Main parameters influencing the migration speed of oligomers:

1) Formation and structure of the low polymer (dimer-trimer etc.)

2) Molecular weight and melting point

3) Temperature, duration and turbulence of different industrial treatments

4) pH of treatment baths

5) Concentration and distribution of low polymer in fibre

 A key factor for preventing surface deposits from forming is the temperature at which the bath is
drained after any treatment carried out at high temperature. We advise performing this operation
at 1 the highest possible temperature (but in line with the possibilities of the system being used
and the characteristics of the treated fabrics) in order to prevent rapid crystallisation of low
polymers leading to precipitation on the fibrous surfaces. It is best to drain the bath at 120-
130°C.

The presence of oligomers on the fabric may also be due to contact with a dyeing machine
already soiled by such substances. In this connection, periodic cleaning of the systems is the
most efficient remedy -we commend the following recipes:




1.8. 1 -Recipes for cleaning systems

        Recipe for ''caustification'' of low polymer:




NaOH 100%                        5 g/l                            a 130°C/45-60'drain bath +
rinsing

ISOPON SPO                       5 g/l




Or "reducing dispersion'' of low polymer:
NaOH 100%                         5g/1                              a 130°C/45-60'drain bath +
rinsing

OROPON RH                         5 g/l




Or "dispersion/solubilisation'' of oligomers using only carriers:




LIVESTER BF                       5-10 g/l                                   a 130°C/60'droin bath +
rinsing




The following is a summary of the chief precautions aimed at Iimiting oligomers from forming on
the surface.

a) Clean machinery constantly

b) Use a high liquor ratio

c) If possible, dye at temperatures below 130°C (e.g. at 120°C), using LIVESTER BF or LlVESTER
PLD

as carriers

d) Avoid prolonged treatments at 130°C and frequent/sudden temperature changes

e) Add specific anti-oligomer assistants to all pressurised treatments (SEQUION MC 200-

ISOPON SpO-IDROSOLVAN and LlVESTER brands).

f) Drain the bath at highest possible temperature

Remember also that dyeing performed with selected disperse dyes in an alkaline environment is
a safeguard against any oligomer related problems.

If you have to desize a polyester fabric sized with acrylic resins or with soluble polyester resins,

the oligomers can be dispersed after initial washing.

This way encourages the emission of Iow polymers 50 that they can then be fully degraded by
exploiting the combined action of high temperature and soda in the recipe.
This operation is possible using overflow or jet. Here are some indicative recipes.




1.8.2 -Desizing recipe (for acrylic resins on PES fabric) plus ''anti-oligomer
treatment".

1) SEQUION MC 200                        1 ml/l                            90°C/20'; drain bath

  IDROSOLVAN E-CO                        2 g/1

  NaOH 30%                               5 ml/l




2) NaOH 30%                              10 ml/l                           130°C/30'; drain bath

  SEQUION MC 200                         2 ml/l




3) Washing with cold water/5', bath drained again, followed by final acid neutralisation

   with 1 ml/l of 80% acetic acid




I.8.3 -Desizing recipe (for soluble polyester based resin on PES fabric) plus

       ''anti-oligomer treatment".




1) SEQUION MC 200                        1 ml/l                            90°C/20'; drain bath

  IDROSOLVAN E-CO                        2 g/1

  Na2CO3 015 g/1




2) NaOH 30%                              10 ml/l                           130°C/30'; drain bath

  SEQUION MC 200                         2 ml/l




3) Washing with cold water/5', bath drained again, followed by final acid neutralisation
  with 1 ml/l of 80% acetic acid




If the quantity of surface oligomers is not excessive, they may be removed during stripping or
washing following dyeing. The following table shows two recipes with which good results were
obtained.




I.8.4 -Stripping and washing recipes




         Concentrations                     Stripping                        Washing

             In g/l                 (for medium / dark tones)             (for light tones)
           NaOH 30 %                           4                                   1
            Na2S2O4                            2                                   /
          ISOPON SPO                           2                                   2

        T= °C / t =min.                 85 – 90 °C / 30 `                80 – 85 °C / 30`




CHAPTER 2




Desizing polyamide fibre fabrics

II.1 Sizes used / II.2 Capability of sizes to be removed / II. 3 Introduction /

II.4 Desizing fabrics containing sizes with acid acrylic copolymers/

II.5 Desizing fabrics containing sizes with salified acrylic copolymers




II.1 Sizes used
Acid acrylic copolymers : Wisacril FTP / 30 – Wisacril NL 66 – Wisacril 70/30 – Wisacril PDL/30

Salified acrylic copolymers: Wisacril PAM / JET – Wisacril PTA/20




                                           Dry looms                     Water looms
                                    Product        % of dry         Product       % of dry
     Fibre           Torsions
                                                 matter on the                  matter on the
                                                     yarn                           yarn
                                    Wisacril

                                    FTP /30
                  With 150 ÷200
                                    NL 66 –           1÷2
                    Twists / m
                                    70/30 –
     Flat
                                   PDL / 30 -
    PAM 6
                                    Wisacril
   And 6,6
                   With parallel    FTP /30                         Wisacril

                    Filaments       NL 66 –         2,5÷4,5       PAM / JET –        2,5÷4

                  Intermingled      70/30 –                         PTA/20

                                   PDL / 30 -
                                    Wisacril

                                    FTP /30
                  With 150 ÷200
                                    NL 66 –           6÷8
                    Twists / m
Textured and
                                    70/30 –
Text / elastane
                                   PDL / 30 -
                                    Wisacril
    PAM 6
                                    FTP /30
   And 6,6
                     Parallel
                                    NL 66 –          5÷12
                   intermingled
                                    70/30 –

                                   PDL / 30 -
II.2 Capability of sizes to be removed




                                       In Water          Acetic acid   Caustic soda
    Hardness °F             0        0     0        30   0             0
    PH                      7        7     7        7    3             12
    Temperature in °C       20       50    90       90   90            90

    WISACRIL PAM/JET                                              
    WISACRIL PTA/20                                               

    WISACRIL NL 66                                                
    WISACRIL 70/30                                                
    WISACRIL FTP/30                                               
    WISACRILPDL/30                                                




KEY:




 : Good film dissolution

 : Reasonably good film dissolution (in any case, we advise you to use a temperature of at
least

l       : Difficult / partial film solubility

II. 3 Introduction

In most cases, polyamide fibre fabrics either have no size at all (water jet I00rn5 with twisted or
intermingled threads), or have very easy to eliminate sizes (Wisacril NL 66 -70/30 -PDL /30 -
FTP/30).

Due to their very high solubility at any pH value, these resins can be removed from fabrics by
using recipes with alkaline pH for caustic soda, and also with acid pH (acidity is automatically
supplied by the solubilised resin it self). For working with acid pH, our specific detergentıs FIMBIL
OP 90 -under these conditions, there is no need to use a sequestering agent for hardness,
whereas we recommend including a buffer-action dispersing agent in the recipe. However, the
current trend is to desize polyamide thread in an alkaline environment. This partly enables better
emulsification of any waxing product present and, above all, makes it possible to process several
articles without having systematically to change the recipe. In some cases, the handle is more
pleasant as well. In addition to being easy to solubilise, these resins require shorter washing
times and, as a result, nylon fabrics can normally be desized more quickly compared to polyester
fibre fabrics. It was only with the advent of high speed water-jet 100rn5 that the need to further
protect the thread by suitable sizing was perceived (Wisacril PAM JET).
As this type of size must be waterproof, it certainly cannot be easy to dissolve in the manner of
acid acrylic copolymers, and, therefore, treatment baths must be composed with some care to
ensure total removal, by following the procedure we are describing.




II . 4 Desizing fabrics containing sizes with acid acrylic copolymers




II.4.1-On discontinuous machines




a) Jigger




1) Detergent/wetting agent                        2 ml/l                85°C/4 passages; drain
both

  NaOH 30%                                        1-2 ml/l




2) Washing with water at 80°C/2-3 passages; drain both




3) Washing with cold water and, if necessary. acid neutralisation




Recommended detergents: DS 100 -BIOMEGAPAL VS -IDROSOLVAN E-500

Recommended sequestering agents: SEQUION MC 200 -SEQUION M 500




b) Overflow jet

(textured fabrics or fabrics suitable for rope treatment)




1) Detergent/wetting agent                        1-2 ml/l                      90°C/20'; drain
bath
Sequestering agent                               as necessary

NaOH 30%                                         1-2 ml/l

Crack-mark inhibitor                             2 ml/l




2) Washing with water at 800C/10'; drain bath




3) Washing with cold water and, if necessary. acid neutralisation ,




Recommended detergents: IDROSOLVAN E-CO -FIMBIL HOF o

Recommended sequestering agents: SEQUION MC 200 -SEQUION M 500

Recommended crack-mark inhibitors: FELEN 1 00 -ISOPAL A 39




c) Beam




l) Detergent/wetting agent                                  1-2ml/l   90°C/20'; drain
bath

  NaOH 30%                                       1-2 ml/l




2) Washing with water at 80°C/10'; drain both




3) Washing with cold water and, if necessary acid neutralisation




Recommended detergents: IDROSOLVAN E-CO -BIOMEGAPAL VS

Recommended sequestering agents: SEQUION MC 200 -SEQUION M 500

II.4.2- On continuous machines
Treatment bath:




1) NaOH 30%                              1-2 ml/l                      90-95°C/ (permanence
time

   Detergent/wetting agent               2-3 ml/l                              according to
system used)

  Sequestering/dispersing agent                     as necessary




2) Washing with water at 9O-95°C in at least 2 bowls




3) Washing with cold water and, if necessary, acid neutralisation




Recommended detergents: DS 1 00 -BIOMEGAPAL VS

Recommended sequestering agents: SEQUION MC 200 -SEQUION M 500




Notes on the process Partially drain off by overflows, replacing the treatment bath and
washing waters.




II.5 Desizing fabrics containing sizes with salified acrylic copolymers




II.5. 1 -On discontinuous machines




a) Jigger




1) IDROSOLVAN MX                         6-8 ml/l                              90°C/4
passages; drain bath

     Na2CO3                              2 g/l




or




1) Detergent/wetting agent               2 ml/l                          90°C/4 passages; drain
bath

Sequestering/dispersing agent            as necessary

Na2CO3                                   5-7 g/l




2) Washing with soft water at 9O°C/2-3 passages; drain bath




3) Washing with cold water and, if necessary, acid neutralisation




Recommended detergents: DS 1 00 -BIOMEGAPAL VS -IDROSOLVAN E-500

Recommended sequestering agents: SEQUION MC 200 -SEQUION M 500

Multi-purpose product: IDROSOLVAN MX




b) Overflow -Jet (textured fabrics or fabrics suitable for rope treatment)




1) IDROSOLVAN MX                         5-7 ml/l                               90°C/30'; drain
bath

     Na2CO3                              2 g/l




or
1) Detergent/wetting agent               1-2 ml/l                          90°C/30'; drain
bath

     Sequestering agent                  as necessary

     NaOH 30%                            3-4 ml/l




2) Washing with soft water at 80°C/10'; drain bath




3) Washing with cold water and, if necessary, acid neutralisation




Recommended detergents: IDROSOLVAN f-CO -FIMBIL HOF

Recommended sequestering agents: SEQUION MC 200 -SEQUION M 500

Multi-purpose product: IDROSOLVAN MX

c) Beam




1) IDROSOLVAN MX                         5-7 ml/l                          90°C/30'; drain
bath

     Na2CO3                              2 g/1




or




1) Detergent/wetting agent               1-2 ml/1                   90C°/20'; drain bath

     Sequestering agent                  as necessary

     NaOH 30%                            3 ml/l




2) Washing with soft water at 80°C/10'; drain bath
3) Washing with cold water and, if necessary, add neutralisation




Recommended detergents: IDROSOLVAN E-CO -BIOMEGAPAL VS

Recommended sequestering agents: SEQUION MC200 -SEQUION M 500 1

Multi-purpose product: IDROSOLVAN MX




II.5.2- On continuous machines




Treatment bath:




1) IDROSOLVAN MX                                10-15 ml/l          90-95°C/ (permanence
time

Na2CO3                                          2 g/1               according to system
used)




or




1) NaOH 30%                                     5 ml/l              90-95°C/ (permanence
time

Detergent/wetting agent                                  2-3 ml/l
       according to system used)

Sequestering/dispersing agent                   as necessary




2) Washing with soft water at 90-95°C in at Ieast 2 bowls




3) Washing with cold water and, if necessary, add neutralisation
Recommended detergents: DS 100 -BIOMEGAPAL VS

Recommended sequestering agents: SEQUION MC 200 -SEQUION M 500

Multi-purpose product: IDROSOLVAN MX

Notes on the process:

Partially drain off by overflows, replacing the treatment bath and washing waters.




CHAPTER 3




Desizing rayon acetate fabrics




III.1 Sizes used / III.2 Capability of sizes to be removed / III.3 Introduction /

III.4 Desizing fabrics containing sizes with acrylic copolymers for dry looms/

III.5 Desizing fabrics containing sizes with vinyl and acrylic copolymers for water
looms




III.1 Sizes used




Acrylic copolymers : Wisacril AF 30 – Wisacril AF 30/23 – Wisacril NVC – Wisacet WJL

Vinyl acrylic copolymer: Wisacet AJ205




     Fibre             Torsions                Dry looms                   Water looms
                                           Product       % of         Product       % of dry
                                                           dry                     matter on the
                                                         matter                        yarn
                                                         on the
                                                          yarn
                                       Wisacril AF/30-    3÷4
                     With 60÷90
                                             23
                                       Wisacril AF/30      3÷4
                      Twists/m
                                       Wisacet AJ205       3÷4
   ACETATE
                     With parallel     Wisacril AF/30-     4÷5      Wisacet WJL
                                             23
                                                                                       3÷4
                       Filaments       Wisacril AF /30     4÷5
                                                                    Wisacril NVC
                     intermingled      Wisacet AJ205       4÷5
                        Twised         Wisacet AJ205       4÷6
   ACETATE
                        Parallel                           5÷7
                                       Wisacet AJ205
    NYLON
                     intermingled




Notes : The indicated percentages refer to warp only, not to the entire fabric.




III.2 Capability of sizes to be removed




                                 In Water           Acetic acid   Caustic soda
Hardness °F            0       0     0      30      0             0
PH                     7       7     7      7       3             12
Temperature in °C      20      50    90     90      90            90

WISACRIL AF 30                                               
WISACRIL AF 30/23                                            

WISACET AJ 205                                               
WISACET WLJ                                                  
WISACRIL NVC                                                 
KEY:

:Good film dissolution

:Reasonably good film dissolution (for WISACET AJ 205, we recommend not going below pH7
.5 -

   8 in order to avoid considerably reducing its dissolution times; for Wisacril on the other hand,

  we advise using temperatures above 7O°C in order not to overly reduce size dissolution
speed).

:Difficult/partial film solubility




III.3 Introduction




To select the best desizing conditions for acetate rayon, one must in particular consider the
delicacy of the fibre being processed. The following are necessary for this fibre: treatments at a
temperature not exceeding 80-85°C, use of sodium carbonate and not caustic soda, plus
machinery preventing increases from forming.

In the ''Capability of sizes to be removed'' table, the film dissolution tests therefore refer to the
behaviour of the type of size without any reference to treatment danger fur the fibre.

Bear in mind that acetate rayon has a sufficiently high ''finishing oils'' percentage (2.5 -3%).

These are the most common treatment cycles:

A) simultaneous desizing and dyeing

B) 1) desizing on continuous machine;

   2) dyeing in jigger

   or

  1) desizing in jigger;

  2) dyeing in jigger.

In our opinion, the B) cycles are better for providing repeatable results and, therefore, safeguard
against any faults, due to possible interaction of sizing products with the different components of
dyeing baths. Cycle A) can be effected with resins that are particularly soluble under dyeing
conditions. To ensure good results, we advise you, in any event, to run preliminary tests using
the standard conditions in the available systems.




III.4 Desizing fabrics containing sizes with acrylic copolymers for dry looms




III.4.1 - On discontinuous machines




a) Jigger




1)IDROSOLVAN MX                                  8-10 ml/l               85°C/4 passages; drain
bath




or




1) Detergent/wetting agent                       2 ml/l                  85°C/4 passages; drain
bath

     Na2CO3                                      0,5-1 g/1

     Sequestering/dispersing agent                        as necessary




2) Washing with soft water at 8O°C/2-3 passages; drain bath




3) Washing with cold water and, if necessary acid neutralisation




Recommended detergents: DS 100 -BIOMEGAPAL VS -IDROSOLVAN E-SOO

Recommended sequestering agents: SEQUION MC 200 -SEQUION M 500

Multi-purpose product: IDROSOLVAN MX
b) Overflow -Jet

Fabrics in 1 00% acetate rayon do not usually withstand rope treatment.




c) Beam




1) IDROSOLVAN MX                                 6-8 ml/l                  85°C/20'; drain
bath




or




1) Detergent/wetting agent                       1-2 ml/l                  85°C/20'; drain
bath

     Na2CO3                                      0,5-1 g/1

     Sequestering/dispersing agent                          as necessary




2) Washing with soft water at 80°C/10'; drain bath




3) Washing with cold water and, if necessary, acid neutralisation




Recommended detergents: IDROSOLVAN E-CO -BIOMEGAPAL VS

Recommended sequestering agents: SEQUION MC 200 -SEQUION M 500

Multi-purpose product: IDROSOLVAN MX




III.4.2- On continuous machines

Treatment bath:
1) IDROSOLVAN MX                                 6-8 ml/l                      90-95°C/
(permanence time

  Na2CO3                                         0,5-1 g/1             according to system
used)




or




1) Na2CO3                                        1-2 g/1               90-95°C/ (permanence
time

Detergent/wetting agent                                     2-3 ml/1           according to
system used)

Sequestering/dispersing agent                    as necessary




2) Washing with soft water at 85-90°C in at Ieast 2 bowls




3) Washing with cold water and, if necessary. acid neutralisation




Recommended detergents: 05 100 -BIOMEGAPAL VS

Recommended sequestering agents: SEQUION MC 200 -SEQUION M 500

Multi-purpose product: IOROSOLVAN MX

Notes on the process: Partially drain off by overflows, replacing the treatment bath and
washing waters.




III.5.1- Desizing fabrics containing sizes with vinyl and acryliccopolymers for water
1ooms




III.5.1 -On discontinuous machines
a) Jigger




1) IDROSOLVAN MX                                 6-8 ml/l                         85°C/4
passages; drain bath

     Na2CO3                                      0,5-1 g/1




or




1) Detergent/wetting agent                       2 ml/l                    85°C/4 passages; drain
bath

     Na2CO3                                      2-3 g/1

     Sequestering/dispersing agent                          as necessary




2) Washing with soft water at 80°C/2-3 passages; drain bath




3) Washing with cold water and, if necessary. acid neutralisation




Recommended detergents: 05 100 -BIOMEGAPAL VS -IOROSOLVAN E-500

Recommended sequestering agents: SEQUION MC 200 -SEQUION M 500

Multi-purpose product: IOROSOLVAN MX




b) Overflow -Jet

Fabrics in 1 00% acetate rayon do not usually withstand rope treatment.
c) Beam




1) IDROSOLVAN MX                                 6-8 ml/l
       85°C/30' drain bath

     Na2CO3                                      0,5-1 g/1




or




1) Detergent/wetting agent                       1-2 ml/l                         85°C/30'; drain
bath

     Na2CO3                                      2-3 g/1

     Sequestering/dispersing agent                          as necessary




2) Washing with soft water at 80°C/10'; drain bath




3) Washing with cold water and, if necessary. acid neutralisation




Recommended detergents: IDROSOLVAN E-CO -BIOMEGAPAL VS

Recommended sequestering agents: SEQUION MC 200 -SEQUION M 500

Multi-purpose product: IDROSOLVAN MX




111.5.2- On continuous machines

Treatment bath:




1) IDROSOLVAN MX                         8-10 ml/l                         85-90°C/ (permanence
time

Na2CO3                            1-2 g/1                            according to system used)




or




1) Na2CO3                                   3-5 g/1                         85-90°C/ (permanence
time

  Detergent/wetting agent                   2-3 ml/1                        according to system
used)

     Sequestering/dispersing agent                    as necessary




2) Washing with soft water at 85-90°C in at Ieast 2 bowls




3) Washing with cold water and, necessary, acid neutralisation




Recommended detergents: DS 1 00 -BIOMEGAPAL VS

Recommended sequestering agents: SEQUION MC 200 -SEQUION M 500

Multi-purpose product:IDROSOLVAN MX

Notes on the process:

Partially drain off by overflows, replacing the treatment bath and washing waters.




III.5.3- Alternative recipe in jigger (to prevent saponification)

This recipe makes it possible to remove the more difficult to solubilise acrylic resins, although
using

a minimum quantity of alkali and thus preventing any saponification of the acetate.
1) IDROSOLVAN MX
6-8 ml/l
         85°C/4 passages; drain bath

     Na2CO3                              0,5:1 g/1




or




1) Detergent/wetting agent               2 ml/l                     85°C/4 passages; drain bath

     Na2CO3                              0,5-1 g/1

     IDROSOLVAN M 90 /M 80               6 ml/l

     Sequestering/dispersing agent                as necessary




2) Washing with soft water at 8O°C/2-3 passages; drain bath




3) Washing with cold water and, if necessary, acid neutralisation




Recommended detergents: DS 100 -BIOMEGAPAL VS -IDROSOLVAN E-500

Recommended sequestering agents: SEQUION MC 200 -SEQUION M 500

Recommended specific products: IDROSOLVAN M 80 -IDROSOLVAN M 90 -IDROSOLVAN MX




CHAPTER 4




Desizing fabric in viscose rayon and cuproammonium thread




IV.1 Sizes used / IV.2 Capability of sizes to be removed / IV.3 Introduction /

IV.4 Specimen desizing recipes / IV.5 Crépe fabrics
IV.1 Sizes used




Acrylic copolymers : Wisacril AF 30 – Wisacril AF 30/23 – Wisacril RV EXTRA – Wisacet VA

Modified polyvinyl alcohol: Wisal AC3/25 - Wisal AC3/25/R02 – Wisal T20/1




      Fibre             Torsions                            Dry looms
                                              Product       % of dry matter on the yarn
                      With 60÷90          Wisacril AF/30-23            2÷3
                                           Wisacril AF/30              2÷3
                       Twists/m           Wisacril RV Extra            2÷3
    ACETATE
                      With parallel       Wisacril AF/30-23            4÷6
                                           Wisacril AF /30             4÷6
                       Filaments
                                             Wisal AC3/25               6÷9

                                                Wisal
                      With parallel
    ACETATE                                  AC3/25/R02

                       Filaments
     NYLON
                                                                        5÷8
                                             Wisal T20/1
                           twisted           Wisacril VA                3÷4




Notes: The indicated percentages refer to warp only, not to the entire fabric




IV.2 Capability of sizes to be removed




                                  In Water           Acetic acid   Caustic soda
Hardness °F            0        0     0      30      0             0
PH                     7        7     7      7       3             12
Temperature in °C      20       50    90     90      90            90

WISACRIL AF 30                                                
WISACRIL AF 30/23                                             

WISACRIL RV                                                   
EXTRA
WISACRIL VA                                                   
WISAL T 20/1                                                  
WISAL AC 3/25                                                 
WISAL 3/25/R0 2                                               




KEY:

: Good film dissolution

:Reasonably good film dissolution

   (for Wisacril AF 30 and Wisacril AF 30/23 it is preferable to maintain temperature above 70°C

     to accelerate size dissolution time, whereas for Wisal products, high quantities of soda and

    electrolytes may slow down size dissolution time and, in some cases, dangerous
agglomerates

    could form depending on subsequent squeezing and drying). Wisacril RV EXTRA is

    extremely soluble even on acid pH, however, we advise you not to go below the pH 4
threshold.

: Difficult/partial film solubility

IV .3 Introduction

These are the most common treatment cycles:

1) -Desizing and dyeing in jigger -drying

2) -Desizing on continuous machines -dyeing in jigger -drying

3) -Simultaneous desizing and dyeing




If you have to dye cuproammonium or viscose articles sized with resins containing polyvinyl
alcohol, without any preliminary desizing (cycle 3), preliminary tests are necessary to check the
size's ''compatibility'' with respect to the different dyeing electrolytes.

In fact, it is common knowledge that polyvinyl derivatives are highly sensitive to sulphates,
caustic soda, and other highly electrolytic substances or substances with alkaline pH.

If you have to dye using direct or reactive dyes in the jigger without preliminary desizing, we
advise you to Limit the quantity of sulphates (maximum concentr. of 30 g/l), pre-diluting before
loading.
Adding gradually in steps helps ensure greater bath stability.

For dark shades, requiring extra salinity, we recommend adding sodium chloride to the dyeing
bath, as this salt has a lesser influence on PVA solubility.

Due to complete in-water solubility of polyvinyl polymer, cycles no. 1 and 2 make for totally
worry-free operation and we, therefore, recommend them.




IV .4 Specimen desizing recipes




IV.4. 1 -On discontinuous machines




a) Jigger




1) IDROSOLVAN MX                         6-8 ml/l                         90°C/4 passages; drain
bath




or




1) Detergent/wetting agent               2ml/l                     90°C/4 passages; drain bath

     Na2CO3                              2-3 g/1

Sequestering/dispersing agent            as necessary




2) Washing with soft water at 85°C/2-3 passages; drain bath




3) Washing with cold water and, if necessary, add neutralisation




Recommended detergents: DS 100- BIOMEGAPAL VS -IDROSOLVAN E-500
Recommended sequestering agents: SEQUION MC 200 -SEQUION M 500

Multi-purpose product: IDROSOLVAN MX




b) Overflow -Jet -Beam

These machines are generally little used for preparing fabrics in viscose rayon and/or !
cuproammonium, as these fibres easily tend to create creases.

If you have to work with these systems, especially for rope treatment, we advise you to use
products with a crack-mark inhibiting/slipping action (ISOPAL A 39 or FELEN 1 00) as they cut
down this risk.




IV.4.2- On continuous machines

Treatment bath:




1) IDROSOLVAN MX                           8-10 ml/l                  90°C/ (permanence time
according

                                                                     to system used)




or




1) Na2CO3                                  3-4 g/1                    90°C/ (permanence time
according

     Detergent/wetting agent               2-3 ml/l                          to system used)

     Sequestering/dispersing agent                    as necessary

     Crack-mark inhibitor (if necessary)   2-3 ml/l




2) Washing with soft water at 85-90°C in at Ieast 2 bowls




3) Washing with cold water and, if necessary, acid neutralisation
Recommended detergents: DS 100 -BIOMEGAPAL VS -IDROSOLVAN E-CO

Recommended sequestering agents: SEQUION MC 200 -SEQUION M 500

Multi-purpose product: IDROSOLVAN MX

Recommended crack-mark inhibitors: ISOPAL A 39 -FELEN 1 00

Notes: The chief difficulty in preparing these articles is emulsifying the avivage oils of which
great

quantities are present on both the warp and weft threads.

Consequently, selecting a good detergent/emulsifier for use in the process is essential.




IV.5 Crépe fabrics




As these threads are highly twisted, they are not usually sized, but use is made of products
designed to fix such twisting (oils; PVA derivatives; CMC).

These products are easy to remove and, therefore, do not require any special treatments.

However, incomplete removal of these substances may obstruct shrinkage of the article, and as a
result, the importance of using suitable assistants for preparation should not be underestimated.
To endow the articles with a crepe finish, machines in which the fabric is wholly tension-free are
used (e.g. Maser VB for continuous treatments and flow/jets for discontinuous treatments). The
final result of the treatment is closely linked to the regularity/uniformity of article shrinkage, and,
therefore, both the recipe and operating conditions must be set with the aim of encouraging this
characteristic. If the créping treatment is insufficient, in addition to the problems of unity, stripes
or rougher handle problems may also arise.

The presence of caustic soda in the recipe and high temperature are factors that encourage the
fibres to swell and, consequently, shrinkage and final softness of the fabric. Special attention
must also be addressed to drying, to avoid a rigid handle due to excessive tension or
temperatures. A post-treatment reducing this ''fault'' is applying silicone-based micro-emulsions
by padding -like our CEROFIL RP at 15-20 ml/l.

To ensure maximum shrinkage of the article, two preparation treatments are often required:

the first is executed with the highest concentration of caustic soda.

For example, in the case of crepe articles for linings, first continuous caustic treatment at 4-5°Bé
is undertaken (Mezzera VB) at a temperature of 30-40°C/ 15', followed by washing/ créping also
in continuous. Other articles, less sensitive to wrinkling, are re-treated in discontinuous.
Those without a continuous Iine such as Mezzera VB, are advised to execute the treatments in
over-flow. it is very important not to place the goods in cold baths, since the fibre could suddenly
stiffen thus encouraging creases. Consequently, the ideal bath temperature should never be
below 40oC in alkali and must be maintained as high as possible (over 90°C) during
shrinkage/washing.

Due to these problems, always avoid sudden temperature variations during the different
preparation and washing stages.




To conclude, we suggest the following detergents/emulsifiers for these articles:

-IDROSOLVAN E-500 and OTTIN E-70 (for continuous processes) at 2-4 ml/l

-IDROSOLVAN E-CO and FIMBIL HOF (for discontinuous treatments) at 2-3 ml/l

The most suitable crack-mark inhibiting/slipping substances include:

-ISOPAL A 39 (high crack-mark inhibiting effect giving the fabric a soft hand)

-FELEN 100 (high slipping effect)




CHAPTER 5




Desizing mixed fabrics




V.1 Acetate rayon or cuproammonium thread or nylon / V.2 Polyester – cotton /

V.3 Polyester – viscose staple or viscose rayon / V.4 Polyamide – cotton /

V.5 Polyester – silk / V.6 Acetate rayon – silk / V.7 Acetate rayon – wool /

V.8 Polyamide – elastane




V.1 Acetate rayon or cuproammonium thread or nylon

Depending on the thread used in chain direction, the type of sizing is as used for 1 00% fabrics.
Therefore, the suggestions we have already made apply here too, in view of the greater delicacy
of fibre in mixed fabrics. If acetate rayon is present, remember the limitation whereby a
temperature of 85°( cannot be exceeded (except in special cases).

As concerns mixed acetate viscose fabrics, do not exceed 2 g/l of sodium carbonate in the recipe,
especially if subsequent dyeing is single-bath. Moreover, the following mixed fibre articles can be
desized in the same bath: acetate/cuproammonium; acetate/viscose, acetate/nylon, viscose or
cuproammonium/nylon (only if nylon is present in the weft).




V. 1. 1 -Specimen recipe




1) Detergent/wetting agent               2-3 ml/l                          80-85°C/(permanence
time

  Na2CO3                                 1-3 g/1                    according to system used)

  Sequestering/dispersing agent as necessary




2) Washing with soft water at 80°C




3) Washing with cold water and, if necessary, acid neutralisation




Recommended detergents: DS 100 -BIOMEGAPAL VS -IDROSOLVAN E-500 -IDROSOLVAN E-CO

OTTIN E-70

Recommended sequestering agents: SEQUION MC 200 -SEQUION M 500

Notes: These articles can be desized also with the recipe shown in paragraph V.3 .1 , in the
same desizing bath. In this case, the pH of the bath must be maintained at approximately 1 0.




V.2 Polyester – cotton

Polyester fibre generally makes up the wart direction. If acrylic size is present, and as work must
necessarily proceed in an alkaline environment (in view of the presence of cotton), there are no
problems. 50 this operation can be combined with bleaching/alkaline scouring etc., thus avoiding
separate desizing. If, on the other hand, resins containing soluble polyester are presf1nt on the
warp, desizing is not possible directly during bleaching/scouring, because the resin does not
support alkaline treatments. Furthermore, the calcium and magnesium salts, which abound in
cotton, may compromise good size removal. In this specific case, a sizing product to use instead
of soluble polyester sizes is WISAL AP 25, which, although it is just as efficient on a dry I00rn,
has solubility characteristics similar to those of acrylic sizes.




V .3 Polyester -viscose staple or viscose rayon

The same considerations regarding fabrics mixed with cotton apply (chapter V.2.), but as these
are cellulose fibres that are more sensitive to alkali, overly forceful treatments must be avoided;
and therefore using sodium carbonate, not caustic soda. An even better solution would be to
partially replace sodium carbonate with specific products with buffered organic alkalinity such as
our IDROSOLVAN.

Furthermore, these brands also make it possible to prepare a single-bath desizing recipe, without
necessarily having to identify the type of resin present on the polyester thread.




V.3. 1 -Single-bath specimen recipe (exact recipe to be optimised according to system
and articles

        to be desized)




1) IDROSOLVAN MX                         6-10 ml/l                        80-85°C/(permanence
time

  Na2CO3                                 0,5-1 g/l                        according to system
used)




or




1) IDROSOLVAN brands                     4-8 ml/l                                  80-
85°C/(permanence time

  Detergent/wetting agent                  0-3 ml/l                                   according to
system used)

  Na2CO3                                   0,5-1 g/1

  Sequestering/dispersing agent                       as necessary




2)Washing with soft water at 80 °C




3) Washing with cold water and, if necessary acid neutralisation




Recommended detergents: 05 1 00 -BIOMEGAPAL VS -IOROSOLVAN E-500 -IOROSOLVAN E-CO -
OTTlN E-70

Recommended sequestering agents: SEQUION MC 200 -SEQUION M 500

Recommended specific product: IOROSOLVAN M 90 or M 80 or M 450 or MX

Notes: If you wish to proceed with''traditional'' desizing, use the appropriate recipes according to
type of size used (chapter 1).




V.4 Polyamide -cotton

These fabrics can be treated as if they were made up to 1 00% polyamide fibre.

As sizes containing acrylic resins are present on the polyamide, the desizing operation can be
combined with bleaching or cotton alkalisation. In the first case, if you wish to proceed with pad-
batch bleaching, you must take into account that highly acid acrylic resins are present on the PA
warps. They would cause considerable, irregular neutralisation of the impregnation bath leading
to overturning risks visible during dyeing.

To avoid these risks, we advise you to prepare a suitable reinforcing bath and evaluate by
systematic titrations the concentration of caustic soda in the soaking bowl during treatment
hours.

However, in the light of our experience, we think that preliminary desizing is a surer solution,
especially if, after pad-batch bleaching, the article is not subjected to other preparation
treatments (greater overturning risk). The desizing recipe can be combined with an acid cracking
process, partly exploiting the acidity of acrylic resin, or using the classic recipes containing caustic
soda, which enable simultaneous scouring of cellulose fibre (chapter 11.4).
V.4. 1 -Acid desizing recipe




1) Detergent/wetting agent               3 ml/l                  90°C/(permanence time
according

  Sequestering/dispersing/               1-2 ml/l                        to system used)

  buffering agent




2) Washing with water at 90°C




3) Washing with cold water




Recommended detergents: FIMBIL OP 90 -BIOMEGAPAL VS

Recommended sequestering agents: SEQUION TP 5

Notes: Be sure to neutralise the pH in the fabric, by thoroughly washing it before impregnating in

the pad-batch bleaching bath.




V.5 Polyester -silk

These fabrics are produced on dry looms. The type of size usually contains soluble polyester
resin.

Consequently, our considerations in chapter 1.4 are applied, desizing before degumming the
silk (we remind you to use IDROSOLVAN 5 40 or 5 35 for this process-see chapter VII).

By using these products on continuous machines (e.g. Mezzera VB), you can both desize
polyester fabrics with warps sized with acrylic resins, and degum silk fabrics, all with a single
recipe.

 Instead, this treatment is not recommended if polyester sizes are present, in view of the
presence and high concentration of electrolytes and alkali.
V.5.1 .DESIZING/DEGUMMING REClPE (only if acrylic resins are present)
This recipe is suitable for Mezzera VB type continuous systems or for star type discontinuous
systems.




1) Specific product                     4-8 ml/l                         98°C/60'

Detergent/ emulsifier                   1-2 ml/l

Green soap                              0-6 g/1




2) Washing with soft water at 9O°C




3) Washing with cold water




Recommended detergents: LAIFFL 27 -OTTIN E-70 -IDROSOLVAN E-500

Recommended specific products: IDROSOLVAN 5 40 (if the soap is not used)

IDROSOLVAN 5 35 (if the green soap is used)

Notes: If purified water cannot be used and green soap is not included in the recipe, we
recommend adding a specific sequestering agent (SEQUION MC 200). If green soap is present,
SEQUION CA is more efficient




V .6 Acetate rayon -silk

Acetate rayon is usually employed for the warp direction and, therefore, the sizing products used
are the same as those described in chapter 111. As regards the desizing recipes, bear in mind the
type of size used and the delicacy of acetate fibre. In any event, the indications in chapter 111
for 1 00% acetate rayon fabrics apply here too.

Degumming of these articles in a Mezzera VB machine is executed at a temperature in the range
of 1 92-93°C max., reducing the quantity of sodium carbonate from 2 to 1 g/l in the main bowl,
and changing back to 2 g/l for passage of 100% silk fabrics.




V .7 Acetate rayon or viscose rayon -wool
In these cases too, rayon is used for the warp direction and size can therefore contain acrylic
and/or vinyl resin. For the very delicate nature of this mixed fabric, especially due to the
presence of wool which does not readily support hot treatments with alkaline pH, it is essential to
prepare a washing recipe that includes specific products with buffered organic alkalinity (1
DROSOLVAN M 80 and M 90) which we described in previous chapters.




V.7 .1 .Specimen recipe (for discontinuous systems e.g. overflow)




1) Specific product                      2-3 ml/l                         70-80°C/30'

Detergent/ emulsifier                    1-2 ml/l

Crack-mark inhibitor/slipping agent      2-3 ml/l




2) Washing with soft water at 65°C




3) Washing with cold water and, if necessary, acid neutralisation




Specific product: IDROSOLVAN M 90 ,

Recommended detergents: FIMBIL 3807

Crack-mark inhibitors/slipping agents: FELEN 7 00 -ISOPAL A 39

Notes: To limit the risk of crack-marks, a low heating gradient must be maintained both during
desizing and washing.




V .8 Polyamide -elastane

In woven fabrics, the elastane is usually inserted in the weft, but can also be combined with the
polyamide thread used for the warp. In this case, the acrylic resin concentrations used to size the
warp are at least doubled compared with the usual concentrations for 1 00% polyamide thread.

Desizing recipes suitable for pure polyamide thread can, nevertheless, be used for desizing these
mixed fabrics. However, bear in mind that there is a greater quantity of size on the fabric and
that avivage oils on the elastomer fibre are usually silicone based and, therefore, are much more
difficult to emulsify. The concentration of these oils increases in proportion to the quantity of
elastane fibre.

However, we should mention that in certain articles, elastane may account for as much as 1 0%
of total fabric. Therefore, to emulsify these oils, the concentration of surfactant agent must be
increased, selecting a suitable detergent such as DS 16 (for use on continuous Iines) and
IDROSOLVAN E-ca for treatments in high turbulence machines.

Pre-washing at low temperature (35-40°C) in the presence of the above mentioned surfactants,
makes it possible to emulsify a high percentage of these oils.




CHAPTER 6




VI.1 Rapid quality tests/ VI.2 Chromatic identification of type of size on PES fibre/

VI.3 Determining sizing products by weighing/




VI.1 Rapid quality tests/

The table shows the size product families that can be found on continuous threads available on
the market. This is useful for initial selection, for choosing the analytical method and for
identifying the different sizing products.




                                             Triacetate,
 Viscose rayon       Cuproammonium                                Polyamide            Polyester
                                            acetate rayon
                                                                  Poly- and
     Acrylic              Acrylic               Acrlic                                  Acrylic
                                                                 metharcylic
   copolymers           copolymers           copolymers                               copolymers
                                                                    acids
      Vinyl                                     Vinyl                                    Vinyl
                     Vinyl copolymers
   copolymers                                copolymers                               copolymers
                                               Styrene             Acrylic              Water –
                                             copolymers          copolymers             soluble
       PVA                  PVA
                                                  PVA                                 polyesters
FABRIC HANDLE TESTS

To identify PVA- or vinyl derivatives:

Necessary reactive agents: lodine N/100

Procedure: Put a few drops of Iodine N/ 1 00 on the fabric surface. If PVA is present, a rosy
colour is obtained. Vinyl copolymers also give a similar colourimetric reaction.

This test is not recommended if there are starch derivatives on the warp: by reacting with iodine,
they would produce a purple tone that obstructs detection of PVA.




To identify polyacrylic and methacrylic acids:

Necessary reactive agents: pH universal indicator (Iiquid)

Procedure: Put a few drops of pH universal indicator on the polyamide fabric surface, and then
compare the obtained colour using the colourimetric scale for the different pH values.

If the value is below 3.5, it is very Iikely that a highly acid acrylic resin is present on the warp.

Moreover, if the fabric was made on a dry I00rn, presence of acid polyacrylateis almost certain.

If pH is in the range of 4.5 to 7 , the acrylic resin is probably fully or partially salified and,
therefore, is of the type used on water looms.




TESTS ON AQUEOUS EXTRACT




 The following quality tests must be run after boiling the fabric by bain-marie method for 5' in
distilled water, using a Iiquor ratio of not over 1 : 1 0, and, if necessary, concentrating the
extract by prolonged heating. Allow the solution to cool before running the tests.




To identify presence of salified acrylic resins or soluble polyester resins:

Necessary reactive agents: FISSAT DRT (cationic charge reactive agent)

Procedure: Add 1 ml of cationic reactive agent to a test tube containing 5-6 ml of solution taken
from the raw fabric by extraction in water. If the above mentioned resins are present, significant
precipitation will be obtained (caused by the cationic reactive agent interacting with the anionic
resins).
To confirm the presence of salified acrylic resins:

Necessary reactive agents: HCl 37% (concentrated hydrochloric acid).

Procedure: Add a few drops of concentrated HCI to a test tube containing 5-6 ml of solution
taken from the raw fabric by extraction in water. If acrylic resins are present, instantaneous
whitish precipitation will take place.




To confirm presence of soluble polyester resins:

Necessary reactive agents: NaOH 50% (soda in solution).

Procedure: Add a few drops of 50% NaOH to a test tube containing 5-6 ml of solution taken
from the raw fabric by extraction in water. If a soluble polyester resin is present, whitish
precipitation will take place.




To identify presence of PVA or vinyl derivatives:

Necessary reactive agents: HCI 37% (concentrated hydrochloric acid) -Borax -Iodine N/ 1 00

Procedure: Add a few drops of concentrated HCI to a test tube containing 4-5 ml of solution
taken from the raw fabric by extraction in water, and then add borax until you obtain a saturated
solution (with visible bottom sediments).

At this point, the solution must still be acid (check with pH indicator).

If the result is positive, add a few drops of N/ 1 00 iodine. if PVA or vinyl derivatives are present,
a markedly purple/rosy colour is obtained -no colour if other resins are present.




Notes: To identify the type of sizing on a 1 00% PES fabric, a colourimetric test is usually run,
using

a basic dye (this test is described in the following paragraph).




All the tests we have just described help to understand the type of size in the warp, but are not 1
00% certain since the presence of other possible substances -such as avivages, antistatics,
waxing products, etc -can cause interference. In this connection, a preliminary washing in solvent
(perchloroethylene or petroleum ether) of the samples to be analysed before running the tests
described above, eliminates most of such interference.

If, in spite of this, there are no clear reactions to the tests, we recommend instrumental analysis
to clearly identify the various structures present.
VI.2 Chromatic identification of type of size on polyester thread:

Acrylic size (Wisacril) and Polyester size (Wisester)




Necessary reactive agents: 0.25 g/1 solution of ''Methylene blue'' basic dye -Methyl alcohol

Procedure: a) put a sample of the fabric to be tested, at room temperature, for about one
minute in a

solution of methylene blue at 0.25 g/l

b) remove the sample and wash it carefully in running cold water.

c) wash twice in methanol half of the sample dyed blue as described at point 1).




Result: In the presence of acrylic or polyester sizes, after washing the colour is vivid blue.

With polyester resins the blue colour remains also after washing in methanol.

On the contrary, it disappears, becoming almost white, in case of acrylic resins.

Notes: The test with methylene blue in water is used not only for identifying the type of sizing,

but also to check presence or absence of residues or, in other words, complete elimination of
size.

Slight colouring is due to the dye ''dirtying'' the fabric.

If you have any doubts, run a lab test on a perfectly desized sample.

Fabrics which have been subjected to strong alkaline treatments or with overly acid/alkaline pH,
can take on a slight colour with this test irrespective of the presence of size residues.

Textured threads and micro-filaments can also be affected by this trouble.

Only by acquiring experience with your own articles, will you be able to assess with maximum
precision the type of sizing present, using only the methylene blue test.




This analytic test can also be run by using a 5 g/t solution of Astrazon Red F-3BL - the result of
the colourimetric test is shown below:
VI.3 Determining sizing products by weighing

This is a weighed analysis and entails a desizing treatment, an oil (finish) extraction treatment
and

determination of thread humidity. The size percentage refers to dry, not sized, thread.




PROCEDURE




1) determining humidity place about 3 g (weigh on analytical scale) of fabric in an
appropriate pre-

set filter-weigher and then put in an oven at 1 05°( for 2 hours. Next, put the filter-weigher
containing the fabric in a dryer for 90'; finally, weigh everything on the analytical scales.




2) determining oil (finish)

place about 1 0 g (weigh on analytical scale) of fabric in a Soxhlet extractor, using petroleum
ether.

Gather the extract in the (preset) flask and after allowing to evaporate at 1 05°(/60', weigh at
constant weight on analytical scales.




3) determining weight loss due to washing

place approximately 5 g (weigh on analytical scale) of fabric in a 500 ml beaker and wash by
bain-marie method (the Linitest appliance can also be used).

The washing conditions and relevant recipes to be used depend on both the type of size in the
warp and the type of fibrous substrate. These recipes are summarised in the table on the
following page.




EXAMPLES OF CALCULATION
1) humidity %                 A = thread               B = dry thread

                    C = filter weighers + dry thread               D = filter-weigher tare




                              C-D = B                  A-B = X               % humidity   =   X .1 00

                                                                                  A




2) oil %            E=thread                F = dry thread (calculated by subtracting
humidity)

                    G=flask + oil           H = flask tare




                              G-H = Y                  % oil   =   Y * 100

                                                                          F




3) loss through washing %

                    1 = thread                                     K = dry desized thread

                    L = dry thread (calculated by subtracting humidity)

                    M = filter-weigher + dry desized thread N = filter weigher tare




                              M-N = K                  % oss through washing       =   Z*.l00

                                                                              K




                    L-K = Z




4) % loss through washing -% oil = % SIZE (referred to weight of non sized thread)
+ OTHER

                       COMPONENTS (water soluble substances and low fibrous
                    polymers).
VI.3.1 -Recipes and washing conditions used for determining sizing products by weighing method




     Fibre          Chemical              Washing recipe            Temparature
                                                                    and duration
                  Make – up of                                      of treatment
                      size
                    Acrlic or        Na2CO3            2 g/l            80°C/60`
      PES
                 Acryllic/Vinyl      DS 33*            2 g/l
                     Solube          Na2CO3            0,5g/l
      PES         polyester or                                          80°C/60`
                      PVA            DS 33*            2g/l
                 Acid acrlyic or     Na2CO3            2 g/l
       PA                                                               80°C/60`
                  Salified acylic    DS 33*            2 g/l
                                     Na2CO3            1 g/l
 CV-CUP-CMD      Acrylic or PVA                                         70°C/60`
                                     DS 33*            2 g/l
                    Acrylic or       Na2CO3            2 g/l
    CA-CTA                                                              70°C/60`
                  Acrylic/vinyl      DS 33*            2 g/l




*. DS 33 is an anionic/non-ionic standard wetting agent/detergent used by our laboratory.

It enables emulsification of greasy /waxy / oily substances present as ensimages on synthetic
threads.

In the case of mixed fabrics, in order to select the best washing recipe to use, one must first of
all consider the chemical make-up of the size in the warp.

We advise you always to use soft water for both desizing and rinsing.




CHAPTER 7

VII.1 Introduction/ VII.2 Degumming:key process parameters/

VII.3 Systems used for degumming/ VII.4 Degumming recipes/

VII.5 Qualitative colourimetric test to identify sericin
VII.1 Introduction

We decided to include in this publication on desizing synthetic threads, a chapter on silk
preparation.

This is because although silk is a natural/animal fibre, it is nevertheless a continuous thread
(mono-filament) and also because, in its raw state, it requires specific washing treatment.

This treatment can be considered as ''desizing'' in which the synthetic polymer (size) is replaced
by a natural size (sericin). This special preparation is known as degumming.

Preparing this fibre is therefore quite simple.

Degumming only is most often sufficient to obtain a fibre ready for dyeing.

Subsequent light bleaching with hydrogen peroxide is only necessary if the raw silk has an
excessively yellowish pigmentation, bearing in mind the particular sensitivity of this fibre toward
oxidising composites in an alkaline mean.




VII.2 Degumming:key process parameters

Silk fibre consists mainly of two proteins: approximately 70-80% fibroin and about 20-28%
sericin.

Small percentages (1-2%) of some ''impurities'' due to natural fats, salts and fibroin ashes are
also present. The purpose of degumming is to solubilise sericin and take away other natural
impurities that could lead to non-uniform dyeing.

The possibility of fully removing or partly removing sericin, without changing the
physical/mechanical properties of fibroin, is closely linked to the different quantities of amino
acids in the two proteins. For further details on the chemical structure of silk, please consult our
SIT no54

''Silk (part 1 )''.

In this brief section, we shall do no more than provide some general comments concerning the
degumming treatment most in use at the moment, i.e. degumming with synthetic detergents
and/or soaps.




There are essentially four key parameters regulating the degumming process:

1) Temperature

2) Duration of treatment

3) Presence of specific textile treatment assistants
4) pH value of bath




VII.2.1 -Temperature

To speed up degumming, the ideal temperature should be maintained at 98°C, unless the article
is of acetate/silk mixture -in this case we recommend working at a maximum temperature of
93°C to avoid the risk of partially saponifying the acetate, while obtaining a reasonably good
degree of degumming (duration of treatment is generally further increased for such articles).

For particularly heavy/dense fabrics, one can operate under pressure at a temperature in the
range of 110 to 120°C. However, under these drastic conditions, special care must be addressed
to the parameters regulating the process, because the physical properties of silk would be more
likely to undergo irreversible change. it should also be borne in mind that the results of
pressurised degumming do not differ from those obtained by operating at 98°C and, therefore, in
industrial practice, it is preferred to use a cycle ensuring more worry-free operation.




VII.2.2 -Duration of treatment

Duration of treatment is closely linked to the structure of the article to be degummed, operating
temperature, bath pH, presence of specific assistants, and Iastly, it is ''influenced'' by the type of
system available. it can be said, in general, that if a bath is prepared with suitable pH and
temperatures, but without using synthetic detergents and/or soaps, degumming times would be
much longer, and definitely longer than two-three hours.

Above all, the presence in the recipe of specific detergent-buffering-dispersing-
sequestering products such as our IDROSOLVAN S 35 and IDROSOLVAN S 40, makes it
possible to considerably reduce the time required for complete solubilisation of sericin.

By using the recipes shown in paragraph no. 4 of this chapter, sixty minutes are actually enough
to complete the operation. The dispersing/anti-redepositing agents in the two formulas, make it
possible to also use the same degumming bath for several operations by reinforcing the bath at
the J start of each degumming process. For continuous treatment (Mezzera VB), work can
proceed for several consecutive weeks without replacing the degumming bath.

VII.2.3 -Degumming assistants

The properties making a positive contribution to the degumming process can be found in the
following products:




A) Detergent with wetting and emulsifying action (our LAIF FL 27 -OTTIN E-70)

B) Sequestering agent with dispersing action (our SEQUION 30Na30 -SEQUION CA)

C) Buffering -alkalinity provider -anti-precipitant -dispersing -''process accelerator'' (our
IDROSOLVAN 5 35 and 5 40)
A) The oldest detergent, which is however still used in this process as it helps obtain articles with
a particularly soft handle, is olive oil soap or green sulphur soap. In addition to Iending softness,
its action is particularly efficient in emulsifying silk's natural waxes/fats.

Users of this soap should take the following precaution: check if the soap is completely
solubilised before starting degumming. To speed up solubilisation, producers market the soap in
the form of flakes or ''short spaghetti''. Compared to soap, synthetic detergents have several
advantages including their greater versatility and precision in automated dosing systems, their
better emulsifying/wetting power and lower sensitivity toward calcium and magnesium
(hardness) ions supplied by both mains water and by the fabrics being processed.




B) As we said, if soap and hardness are present at the same time, a specific sequestering agent
must be used in the recipe, which is able to form complexes containing Ca and Mg ions, with
stability 1 constants higher than those of the corresponding calcareous soaps. The most
appropriate of our products for this purpose is SEQU ION CA. In any event, the presence of 1
DROSOLVAN 5 35 in the recipe ensures fairly worry-free work because this product contains a
sufficient quantity of suitable sequestering agent.




C) Gradual degradation of sericin, which, as we know, consists mainly of highly acid amino acids,
leads -during degumming -to a gradual but constant reduction of the bath pH. This is why buffer-
action products, often considered superfluous in the degumming process, actually play a key role,
especially in processes where bath pH must be in the range of 9.5 to 1 0.5 (continuous
treatment) -this is essential to ensure constant hydrolytic action over several working days.

In addition to providing this process regulating function and having the role of sequestering
agents, IDROSOLVAN 5 35 and 5 40 also have an excellent dispersing action that makes it
possible to maintain the degumming bath efficient for several weeks.

The specific composition of the two products enables rapid degumming of silk without, however,
causing any alteration in fibroin structure, and furthermore, these products can easily be
eliminated by simply rinsing at the end of treatment.




VII.2.4 -Bath pH

The initial pH of a ''fresh'' degumming bath is approximately 11 , but as we said, it tends to drop
quickly during the first few hours of treatment, until it stabilises in the range of 9.5 to 10.5

At higher pH values, there is a risk of damaging the fibre, whereas at near-neutral pH values, the
dissolution speed of sericin is substantially lower. A significantly acid pH value (2-3) would enable
the protein to degrade hydrolytically, but, under these conditions, one would compromise both
the efficiency of soap/emulsifier toward natural greasy substances, and removal/decolouring of
pigments. Moreover, the different degradation products disperse in a Iess stable manner
compared with an alkaline pH bath. The correct alkalinity of the degumming bath is thus
obtained by correctly 1 apportioning the quantities of buffering product and sodium carbonate in
the recipe.




VII.3 Systems used for degumming

In theory, all systems satisfying the following requirements are valid:




1 ) Possibility of keeping the fabric in the bath for at Ieast 50-60'.

2) Possibility of leaving the fabric tension-free.

3) Appliances in which mechanical action (bath circulation -fabric advance) is not excessively
vigorous in order to avoid formation of creases or other defects to which silk -due to its delicate
structure -is particularly prone.




In fabric degumming industrial practice, the two systems described below are mainly used:




Continuous line: MEZZERA VB or VIBILAX These systems consist of a large bowl with
capacity from 20,000 to 40,000 Iitres, which is filled with the degumming bath, and are generally
supported by one or more washing units located downstream of the bowl.

The fabric advances very slowly (system speed in range of 1 0 to 18 m/min), and is performed by
''steel bars'' Iocated on lateral chains, which convey the fabric along the bowl, in ample vertical
layers free from tension and fully immersed in the bath.

The bath is automatically reinforced by automatic dosers.

A degumming bath is usually maintained for at least fifteen consecutive working days, before
being replaced by a fresh bath.




Flow system: STAR Star systems consist of a circular bowl housing the degumming bath, and
an appropriate metal support from whose centre numerous toothed rays reach outward.

The fabric is secured by hand on these metal teeth starting from the inside outward and stays
hung vertically. Then this metal support with the piece hung on it is immersed from the top down
into the bowl containing the degumming bath and is made to rotate slowly.

In this case too, the fabric is free of mechanical tension.
The final washing makes use of hot water only, passing through the same system for a second
time.

If soap was present during degumming, the first rinse is done with the addition of a few
millimetres/litre of ammonia.

This helps remove/neutralise residual soap and makes it possible to reduce the number of
washing baths that would otherwise be required, in order to compensate for the system's limited
mechanical action and, consequently, its inadequate washing efficiency.




VII.4 Degumming recipes

The recipes indicated below are suitable for degumming both fabrics and yarns.

VII.4.1 .Degumming recipe to use if green soap is present




IDROSOLVAN 5 35                        5-6 ml/l                                  98°C/60'

LAIF FL 27 (detergent)                 2 ml/l

Green soap                             4-6 gl/l

Sodium Carbonate                       2 g/l




Followed by boiling and cold washing




VII.4.2 -Degumming recipe to use if green soap is not present




IDROSOLVAN S 40                        6-8 ml/l                                  98°C/60'

LAIF FL 27 (detergent)                 2 ml/l

Sodium Carbonate                       2 g/1
Followed by boiling and cold washing




VII.4.3 -Degumming recipe for silk-acetate mixed fabrics

IDROSOLVAN S 40                           8 ml/l                             93°C/60'

LAIF FL 27 (detergent)                    2 ml/l

Sodium Carbonate                          1 g/1




Followed by washing at 85°C and cold washing




Note: Remember that, especially in the case of continuous degumming treatments, the pH of
the bath must be maintained -by appropriate reinforcements -within a range of 9.5 to 1 0.5.

This is to ensure complete, uniform removal of sericin.




VII. 5 Colourimetric test to identify sericin quality

The test is based on the different dyeing affinities of the two proteins found in silk.

In particular, as sericin has a less crystalline structure than fibroin, it is more receptive to some
specific dyes (usually those with a larger molecule) and, therefore, it can be ''dyed'' much more
intensively-:: already at room temperature -compared to fibroin which appears colourless or
slightly stained. The dyes most used for this test are: CI acid blue 43 and CI direct red 80.

Procedure: immerse the sample to be analysed in a 1 g/l solution of dye, maintained at ambient
temperature, Ieave it for about sixty seconds and then rinse thoroughly.

Sericin remains coloured to a varying degree depending on its quantity, while fibroin remains
almost colourless. The quantity of sericin can also be determined through weighing, by washing
with one of the recipes we previously mentioned.

The analytical procedure and the examples of calculation for determination by weighing are the
same as those indicated in chapter VI.3.

				
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