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					Celvol Polyvinyl Alcohol
Polymer Chemicals Technical Bulletin

New 500 Series CelvolTM Polyvinyl Alcohol
Grades
for Emulsion Polymerization
   three new grades of partially hydrolyzed polyvinyl alcohol (PVOH)
    for emulsion polymerization
   can be used in combination with other Celvol grades to produce
    stable emulsions with a good balance of adhesion and cohesion
    properties
   Low viscosity Celvols provide better rheological control, high
    viscosity Celvols provide better emulsion stability - more options
    to the emulsion polymerizers
Celanese Chemicals has developed Celvol 508, 518 and 530, three new
grades of partially hydrolyzed polyvinyl alcohol (PVOH) for emulsion
polymerization. These new grades represent significant product line
extensions in the Celanese partially hydrolyzed polyvinyl alcohol
offering.

Table #1: Typical Properties of Celvol 508, 518, and 530 PVOH
 Celvol Grade           508      518  530
 Hydrolysis level      87-89   87-89  87-     (1) Preliminary
 (%)                                   89     specification
          1
 Viscosity @ 4%        8.2 –    18 –  30-     (2) 20ºC
                  2                           (3) 4% solids & 20ºC
 solids Solution        8.5     18.7   36     (4) Total volatiles
    3
 PH                    4.5 –   4.5 -  4.5-    includes water
                        6.5      6.5  6.5     (5) Reported as total
                    4                         methanol
 Volatiles, % Max.       5        5     5     (6) As % of Na2O
 VOC’s, % Max.5         0.9      0.9  0.9
 Ash, % Max.6           0.7      0.7  0.50


  Viscosity Curves for                                              Viscosity Curves for
  Partially Hydrolyzed                                              Partially Hydrolyzed
 Celvol:                                                           Celvol:
  Lower Viscosity Range                                             Upper Viscosity Range

                         Celvol Viscosities @20 ºC                                         Celvol Viscosities @20ºC

                     100000                                                            100000
                                  Exist
                     10000        ing                                                               Exist
                                                                                       10000
                                  base
   viscosity (cps)




                                                                                                    ing
                                                                     viscosity (cps)




                                  grade                                                             base
                      1000
                                                                                        1000        grade
                                                                                                    s
                       100
                                                       C205                              100
                                                                                                                         C523
                                                       C508
                        10                                                                                               C530
                                                       C513                               10
                                                                                                                         c540
                                                       C518
                         1
                                                                                           1
                              0     5     10      15   20     25
                                                                                                0       5          10           15
                                          solids (%)
                                                                                                            solids (%)
 Celvol Polyvinyl Alcohol
 Polymer Chemicals Technical Bulletin




 By choosing the appropriate combination of Celvol grades, good
 final emulsion properties balance can be achieved. Low viscosity
 Celvols provide better rheological control while high viscosity
 Celvols provide better emulsion stability. The additional of
 these new grades provides emulsions polymerizers more choices to
 balance these two critical characteristics.

 Test Comparisons
 The following recipe is a reference to evaluate the performance
 for emulsions polymerization based on vinyl acetate monomer.



                                        I. Initial PVOH (5 to 15% of
                                               total)
                                        II. Initial heating 60 to 65ºC
                                        III.
                                        IV. Polymerization 75 to 80ºC
                                        V. Post reaction 80 to 85ºC

                                        Theoretical solids = 50%
                                        Celvol/vinyl acetate ratio = 5.5 to
                                        6.5%
                                        Buffer = Sodium Bicarbonate
                                        Catalyst Redox =
                                        (Persulphate/Bisulfite or Hydrogen
                                        peroxide/sodium formaldehyde
                                        sulfoxilate)



    Table #2: PVAc Emulsion                 Figure #3: Typical particle
Properties Using                        size distribution
    Different Types of Celvol as            of emulsion produced with
Protective Colloid                      different types
    Celvol       508   518       530        of Celvols
    grade
    PVOH/VAM     5.5   5.5       6.5
    ratio wt%
    Emulsion     55    55         55
    % solids
    Viscosity    6300  16500    45000
    cPs
    PH           4.9   4.9       5.0
 Celvol Polyvinyl Alcohol
 Polymer Chemicals Technical Bulletin
    Free         <0.2    < 0.2    < 0.2
                                                              Particle size distribution (Volume)
    monomer %
    Grit %       <0.1    <          <                        20                               Celvol 508
                         0.05     0.01                       18                               Celvol 518
                                                             16                               Celvol 530

                                                             14
 Table #2 shows the results of




                                             frequency (%)
                                                             12
 typical emulsions                                           10
 based on vinyl acetate and the                               8
                                                              6
 effect of these                                              4
 new Celvol grades on the resulting                           2
 emulsion.                                                    0
                                                               0.01     0.1        1          10           100
                                                                              diameter (mm)




      Table #3: Emulsion               Figure #4: Shear rate vs. shear
properties using a                     stress curves for Celvol solution
      combination of Celvol            at 10% solids (max rpms = 500).
508 and 518

    Celvol ratio        50:50
    PVOH/VAM ratio       5.5
    wt%
    Emulsion %            55
    solids
    Viscosity cPs       12,30
    @ 25ºC                 0
    PH                    5.1
    Free monomer %       <0.2
    Grit %               <0.1

       The combination of two Celvol
grades gives
       the option to balance
viscosity if it is required.
Celvol Polyvinyl Alcohol
Polymer Chemicals Technical Bulletin
                                                        Shear Rate vs. Shear Stress
                                                        Celvol 508     Celvol 518
                                                        Celvol 530




                                         1/sec x 10-3
                                                                 dynes/cm2 x 10-3

                                    Figure #4 shows the shear vs. stress
                                    behavior of these three Celvol grade
                                    solutions. Celvol 508 shows a more
                                    Newtonian-like curve, while Celvol
                                    530 displays more shear thinning
                                    (pseudoplastic) behavior.




More Information                                             Celanese Chemicals (North America)
To learn more about the new 500 Series                       1601 West LBJ Freeway
Celvol Polyvinyl Alcohol Grades for                          Dallas, TX 75234
emulsion polymerization,                                     1-972-443-4000
contact your Celanese Chemicals sales
Celvol Polyvinyl Alcohol
Polymer Chemicals Technical Bulletin
representative today.

				
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posted:5/27/2011
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