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Sartomer Coating Concepts Volume IV

VIEWS: 445 PAGES: 11


                                   Volume IV

           • Novel Radiation-Curable Oligomers
             Combining Superior Wear Properties
             with Enhanced Chemical Resistance

           • (Meth)Acrylate Functional Metallic
             Monomers as Metal Adhesion Promoters

           • (Meth)Acrylate Monomer Performance
             Properties in Peroxide-Cure Applications

           • SMA® Resin Additives for Low-Gloss
             Hybrid Powder Coatings

           • Refractive Index in Coating Formulations

           • Technical Information Resources

           • Fall 2001 Trade Show Preview
    Novel Radiation-Curable Oligomers
    Combining Superior Wear Properties
    with Enhanced Chemical Resistance

    In order to be effective, protective    uct behavior. These challenges                                                     Table 1. Functionality of Monomers Tested
    coatings require excellent scratch      make it difficult to offer formula-                                                     Component        Chemical      Functionality
    and abrasion qualities, as well         tion concepts to obtain abrasion-      The application and cure                                        Description
                                                                                                                                    CN-120        Bis A Epoxy            2
    as resistance to chemical attack        resistant, UV-curable coatings.        conditions outlined below were                   CN-985B88     Aliphatic Urethane     2
    and property degradation. These                                                used to prepare all of the test
                                            This study investigates the wear                                                        CN-963E75     Aliphatic Urethane     2
    qualities help ensure the end                                                  panels unless otherwise indicated.               CN-975        Aromatic Urethane      6
                                            properties of an epoxy acrylate
    product’s durability.                                                          Process Conditions                               CN-968        Aliphatic Urethane     6
                                            and compares its performance                                                            CN-999        Aromatic Urethane      2
    Hardness properties are relatively      to two new urethane acrylate            • Substrate Q-Panel,
    easy to obtain using highly             oligomers offered by Sartomer             AL46 Chromate Pretreated             Tests Conducted
    crosslinked materials based on          Company. The first is a difunc-
                                                                                    • Film Thickness:                      All films were very similar in
    highly functional urethane              tional aromatic-based material
                                                                                      50 Microns (2.0 mils)                terms of performance when exam-
    acrylates. However, these               (CN-999), while the other is a
    oligomers, while effective in           hexafunctional, aliphatic-based         • Cure: 300w/in.                       ined from a standpoint of MEK-
    many applications due to their          oligomer (CN-968).                        Hg Lamp 6m/m (20 fpm)                resistance, reverse impact strength,
    high reactivity, may sacrifice the                                              • UV Dose: 700 mj/sq. in.,             adherence, and pencil hardness.
                                            Oligomers and
    coating’s flexibility and resiliency.                                             IL 390 Light Meter                   This study concentrates on the
                                            Compositions Tested
                                                                                                                           differences observed in terms of
    Testing demonstrates that both          Several oligomers were evaluated        • Panels Evaluated After 24 hrs.       wear resistance and physical proper-
    wear properties and chemical            for their abrasion- and wear-          All coatings were applied using a       ties of the cured film. The tests
    resistance can be enhanced using        resistance properties. A bis A         number 40 wire-wound rod and            conducted include CS17 and S33
    urethane oligomers that have a          epoxy was used as the control          cured samples were allowed to           Taber-resistance. The modulus,
    lower functionality and exhibit         oligomer, as it is widely used in      equilibrate for 24 hours in a con-      tensile, elongation at break, as well
    superior flexibility and wear           many applications and well known       stant temperature and humidity          as the glass transition temperature
    properties in comparison to             for its high abrasion- and chemical-   environment (22°C / 55% RH)             of the cured films are also reported
    epoxy acrylates.                        resistance qualities, as well as its   before any tests were conducted.        and correlated to the wear-through
    Abrasion resistance is one of the       rapid cure. These properties were                                              properties observed.
    most complex properties to attain,      compared to urethane acrylate
    as it is both a surface and sub-        oligomers ranging from di- to
    surface property. It can involve        hexafunctionality that were either                          Table 2. Monomer/Oligomer Blend Required to Attain Application
                                                                                                                 Viscosity of 1,000 +/- 100 cps.
    different mechanisms, which may         aromatic or aliphatic in nature.
    or may not be interrelated. In addi-                                                                    Component      CN120    CN985B88    CN963E75   CN975    CN968    CN999
                                            These oligomers were combined                                   Wt. %           54.72     80.00       61.44     72.96    72.00    65.00
    tion, there is no single test method    with the monomers listed in                                     SR-454          13.76      5.30       11.52      7.68     8.00    10.30
    that relates directly to actual prod-   Table 2 and with the photoinitiator                             SR-508          13.76      5.30       11.52      7.68     8.00    10.30
                                            Esacure® KIP100F for testing.                                   SR-212          13.76      5.30       11.52      7.68     8.00    10.30
                                                                                                            KIP100F          4.00      4.00        4.00      4.00     4.00     4.00
                                                                                                            Viscosity      1,088       936         960     1,008      938    1,024
                                                                                                            @ 25º C, cps

1                                                                                                                                                                                     2
                                                                                       (Meth)Acrylate Functional Metallic
    Rad-Cure Oligomers continued                                                       Monomers as Metal Adhesion Promoters

    Wear-Through Resistance                   CS-17 Taber Results                      Overview                              Figure 1. Structure of Metallic Monomers
    The Taber testing was performed           Additional abrasion-resistance           (Meth)acrylate functional metallic                 Oll             Oll
    using the S-33 wheel. The control         testing was conducted using the          monomers are the reactive metal               CH2=C-C-O-M-O-C-C=CH2
    formulation based on the epoxy            CS-17 method, based on weight            salts of ethylenically unsaturated
                                                                                                                                           R          R
    acrylate (CN120) is often used for        loss per 500 cycles (to a maximum        carboxylic acids (see Figure 1),
                                                                                                                                           Where R=H or CH3
    its abrasion-resistance qualities. This   of 2,000 cycles). The wear-through       which can be used to improve
                                                                                                                                                 M=Zn, Ca
    formulation, however, demonstrated        properties of an epoxy acrylate          adhesion of coatings to metal.
    the poorest abrasion resistance of all    (CN120) were compared to a series        The C=C double bond in the
    materials tested, requiring only 83       of neat urethane acrylate oligomers.     (meth)acrylate ester group can       4. 100% Solids 2-Part Epoxy/
    cycles to failure.                                                                 react and be polymerized through        Amine Cure Coatings
                                              The epoxy acrylate exhibited the
                                                                                       a free-radical mechanism using
    Urethane acrylates are also used          poorest abrasion resistance with                                              5. UV-Curable Coatings
                                                                                       peroxides or photoinitiators, or
    for abrasion-resistant coatings           160 milligrams (mg) of weight loss
                                                                                       by a Michael Addition poly-          Experimental
    where improved yellowing resistance       after 2,000 cycles. The difunctional
                                                                                       merization using polyamines.         Three metallic monomers were
    is needed. The aliphatic urethane         aromatic urethane (CN999) com-
                                                                                       Monomers such as zinc diacrylate     selected for evaluation. They
    diacrylate (CN963E75) commonly            pared very favorably with the high
                                                                                       and zinc dimethacrylate are          included PC 300 Zinc Diacrylate,
    used for this application, did            functionality urethanes in terms of
                                                                                       used as peroxide coagents to         PC 303 Calcium Diacrylate, and
    improve wear resistance over the          weight loss after 2,000 cycles. This
                                                                                       crosslink and enhance the proper-    PC 301 Zinc Dimethacrylate.
    epoxy acrylate, but failed at 90          oligomer (CN999) showed 120 mg
                                                                                       ties of metal compression molded     All three monomers are granular
    cycles when used as the base              of weight loss, while the aromatic
                                                                                       rubber parts. A significant amount   solids of 5-10 micron particle
    oligomer in the formulation.              urethane (CN975) dropped to 104
                                                                                       of mold sticking occurs unless an    size, which are insoluble in most
                                              mg of weight loss after 2,000 cycles.
    Excellent abrasion resistance was                                                  internal or external mold release
                                              The best performing system overall                                            monomers and/or solvents and,
    observed when a hexafunctional                                                     is used. Therefore, a study was
                                              was the aliphatic oligomer (CN968),                                           therefore, cannot be readily
    aromatic urethane (CN975) was                                                      conducted to evaluate the use
                                              which exhibited 88 mg of weight loss                                          formulated into a clear coat.
    employed, resisting 115 Taber cycles.                                              of these materials as adhesion
                                              after 2,000 cycles. Again, the CN999                                          Consequently, pigmented or
    A cost-effective compromise to the                                                 promoters for a variety of metals
                                              offers a cost-effective alternative to                                        highly filled coating types where
    CN975 was the difunctional aromat-                                                 in a number of different coating
                                              highly functional urethanes, while                                            the metallic monomers could be
    ic urethane (CN999). It required                                                   technologies where conventional
                                              demonstrating better wear properties                                          added to the grind portion were
    104 Taber cycles to abrade through                                                 liquid (meth)acrylate functional
                                              than the epoxy acrylate.                                                      selected. The metallic monomers
    this coating, as compared to only 83                                               monomer are used.                    were added to a PVC coating, a
    for the epoxy acrylate. This is a 25      Conclusion                               These include:                       polyester alkyd coating, an acrylic
    percent increase in wear cycles.          With proper selection of formulation     1. PVC Plastisol Automotive          coating, an epoxy coating, and a
    When good abrasion qualities and          components, UV-curable coatings             Anti-Chip Coatings                UV-curable coating at 5 parts by
    yellowing resistance are required, the    with excellent wear and abrasion                                              weight or less per hundred parts
                                              resistance can be obtained. The          2. High Solids Polyester
    aliphatic hexafunctional urethane                                                                                       by weight of the total formulation.
                                              oligomers studied, owing to their           Alkyd Enamels
    (CN968) is an excellent choice.
    When tested in the base formula-          structure and reactivity, have high      3. Acrylic Polymer
    tions, this oligomer resisted 110         tensile properties – resulting in           Concrete Coatings
    Taber cycles. When compared to            highly abrasion- and chemical-
    the aromatic version CN968 was            resistant coatings.
    significantly lower in yellowing.
3                                                                                                                                                                       4
    Functional Metallic Monomers continued

    The formulated coatings were           solvents in air-drying, high solids,   exterior durability. A 5% by weight
    then applied to a variety of metal     oil-modified (polyester), alkyd        addition of zinc diacrylate to a 100%
    substrates by the wire-wound-rod       enamels. In these coatings a 1.5%      solids epoxy/amine coating formula-
    hand drawdown method, and              by weight addition zinc dimeth-        tion improves crosshatch adhesion to
    cured under the conditions speci-      acrylate retains the adhesion of a     cold-rolled steel from 0% retention
    fied for each system. Numerous         conventional solvent-borne coating     to 60% retention.
    coating properties were tested for     and improves the crosshatch adhe-
                                                                                  100% Solids
    each system, but the focus was on      sion of an acrylate monomer modi-
                                                                                  UV-Curable Coatings
    testing the adhesive characteristics   fied high solids system from 50%
    of the system with and without the     to 90% on aluminum.                    Acrylated aliphatic urethane oligomers
    metallic monomer additive, as test-                                           are used as the base resin to provide
                                           Acrylic Polymer                        UV stability and abrasion resistance
    ed by either lap shear or crosshatch
                                           Concrete Coatings                      in pigmented UV-cure basecoats for
    adhesion methods.
                                           In some polymer concrete coatings      metal containers, such as beverage
    Results                                for bridge decking or industrial       cans. A 5% by weight addition of zinc
    PVC Plastisol Automotive               flooring, unsaturated polyesters       diacrylate improves the crosshatch
    Anti-Chip Coatings                     (UPRs) and acrylic monomers            adhesion of a typical UV basecoat
    For PVC plastisol automotive           like methyl methacrylate (MMA)         formulation to aluminum from 25%
    coatings, acrylic monomers like        are used as binder resins to impart    retention to 100% retention.
    trimethylolpropane trimethacrylate     strength and chemical resistance.
    (TMPTMA) are used to improve           In these systems a 5% by weight
    chip resistance. A 5% by weight        addition of zinc diacrylate and
    addition of zinc diacrylate to a       calcium diacrylate increases the
    conventional PVC plastisol anti-       adhesion to cold-rolled steel
    chip coating formulation increases     for a polyester-modifed concrete
    the adhesion to electrocoated steel    coating from 220 psi to 460 psi;
    from 5 to 80 psi; the adhesion to      and increases the adhesion for a
    galvanized steel from 50 to 340 psi;   MMA-modified concrete coating
    and the adhesion to cold-rolled        from 640 psi to 1050 psi.
    steel from 10 to 610 psi.              100% Solids 2-Part
    High Solids Polyester                  Epoxy/Amine Cure Coatings
    Alkyd Enamels                          Acrylic monomers like trimethylol-
    For industrial coating applications,   propane triacrylate (TMPTA) are
    acrylic monomers like hexanediol       used as reactive diluents in 2-com-
    dimethacrylate (HDDMA) are             ponent epoxy/amine protective
    used as reactive diluents to replace   coatings to achieve low VOC,
                                           speed dry times, and improve

5                                                                                                                          6
    (Meth) Acrylate Monomer Performance                                            Table 3. Monomers Tested

    Properties in Peroxide-Cure Applications                                         Product
                                                                                      Code      Chemical Description        Abbreviation
                                                                                                                                            Weight         Functionality
                                                                                                                                                                             Moles of
                                                                                      SR-203    Tetrahydrofurfuryl
                                                                                                Methacrylate                   THFMA          170               1               0
                                                                                      SR-285    Tetrahydrofurfuryl
    Sartomer Company offers an              Peak exotherm temperature and                       Acrylate                        THFA          156               1               0
    extensive range of (meth)acrylate       time to peak exotherm from                SR-239    1,6 Hexanediol
                                                                                                Dimethacrylate                 HDDMA          254               2               0
    functional monomers that can be         initiation were recorded.
                                                                                      SR-238    1,6 Hexanediol
    used as reactive diluents, modifiers,                                                                                       HDDA          226               2               0
                                            For viscoelastic and mechanical                     Diacrylate
    or crosslinkers in a wide variety of
                                            property measurement, 1/8" clear          SR-206    Ethyleneglycol
                                                                                                                               EGDMA          198               2               1
    peroxide-cure applications. These                                                           Dimethacrylate
                                            castings were made between glass
    monomers can have a significant                                                   SR-231    Diethyleneglycol
                                            plates at room temperature and                      Dimethacrylate                DEGDMA          242               2               2
    effect on both static and dynamic
                                            then post-cured at 120º C.                SR-205    Triethyleneglycol
    mechanical properties of the coat-                                                          Dimethacrylate                TEGDMA          286               2               3
    ing, thereby influencing flexibility,   Viscoelastic properties were              SR-210    Polyethyleneglycol (200)
                                                                                                                             PEG200DMA        330               2              4.1
    impact, and hardness performance.       measured by DMTA using dual                         Dimethacrylate

                                            cantilever beam geometry at 1 Hz          SR-252    Polyethyleneglycol (600)
    They can also be used to improve                                                            Dimethacrylate               PEG600DMA        770               2              13
    thermal- and chemical-resistance        and temperatures of -100º C to            SR-610    Polyethyleneglycol (600)
                                            250º C. The key measurements                                                     PEG600DA         742               2              13
    properties. The effect the monomer                                                          Diacrylate
    has on performance can be correlat-     recorded are the tan relaxation,          SR-350    Trimethylolpropane
                                                                                                                              TMPTMA          338               3               0
    ed to monomer structure, function-      which correlates to the glass
                                                                                      SR-351    Trimethylolpropane
    ality, molecular weight, monomer        transition temperature (Tg);                        Triacrylate                    TMPTA          296               3               0

    alkoxylation, glass transition tem-     and the rubber modulus                    SR-444    Pentaerythritol
                                                                                                Triacrylate                     PETA          298               3               0
    perature (Tg), and reactivity.          (ERubber=ET + 50C), which
                                            estimates the crosslink density.
    Monomer reactivity and physio-
    chemical properties are presented       Tensile properties were measured
    here to assist formulators and          according to ASTM D638 at             monomers exhibit much higher             indicating that an increase in
    fabricators in monomer selection        23º C and 50% relative humidity.      reactivity than the methacrylate         ethoxylation maintains high
    and behavior prediction.                Test specimens were dumbbell          analog, which is expected due to         reactivity or fast cure.
                                            shaped, and test speed was 2          the higher energy per double
    Monomer Testing                                                                                                        Viscoelastic Properties
                                            mm/min. The key properties            bond (86 vs. 55 kJ/mol). Also,
    Table 3 lists the monomers studied      recorded were tensile strength        trifunctional monomers exhibit           Figure 3 shows the viscoelastic
    for reactivity and viscoelastic/        at break, elongation at break,        faster reactivity than difunctional      properties of SR-238 HDDA vs.
    mechanical properties. Monomer          and Young’s Modulus.                  monomers due to the greater              SR-239 HDDMA as measured
    molecular weight, functionality,                                              number of available double bonds.        by DMTA. The plot of E
    and alkoxylation are also listed so
                                            Results                                                                        modulus vs. temperature shows
    their relationship to performance       Reactivity                            Figure 2 shows a plot of the             that the acrylate monomer exhibits
    can be studied.                                                               effect of ethoxylation on monomer        a higher tan or Tg (68º C vs. 23º
                                            Table 4 shows a comparison of
                                                                                  reactivity. As expected, the peak        C) than the methacrylate, but the
    Reactivity was measured by react-       the reactivity of SR-351 TMPTA
                                                                                  exotherm temperature decreased           methacrylate exhibits a much high-
    ing a small monomer sample with         vs. SR-350 TMPTMA and SR-238
                                                                                  with increasing ethoxylation due         er ERubber modulus (1500 MPa vs.
    dimethyl-p-toluidine (DMPT) and         HDDA vs. SR-239 HDDMA.
                                                                                  to the lower number of double            360 MPa). The graph also shows
    dibenzoyl peroxide (BPO) in a test      According to test results, acrylate
                                                                                  bonds per gram of monomer.               that the methacrylate monomer
    tube at 25º C in a water bath.                                                However, the time-to-peak                exhibits better retention of dynamic
                                                                                  temperature was unchanged,
7                                                                                                                                                                                         8
                                          Monomer Performance
                                          Properties continued

                                                                                  Figure 4 shows the viscoelastic        Table 6 shows the elongation                            and fabricators to easily control
Table 4. Comparison of Acrylate vs.                                               properties for the ethylene glycol     at break and Young’s Modulus                            performance properties such as
         Methacrylate Reactivity                                                                                         values for the ethylene glycol-
                                                                                  series of methacrylate monomers.                                                               reactivity, mechanical properties,
                Monomer       Peak Exotherm          Time to Peak                 In the case of only 1 mole of          based monomers tested. It was                           and thermal and chemical resis-
                               Temperature             Exotherm
                SR-351 TMPTA      305º C                12 min                    ethoxylation, the properties           concluded that increasing the                           tance. In summary, the trends
                SR-350 TMPTMA      40º C                22 min                    of a methacrylate monomer are          moles of ethoxylation increases                         observed are as follows:
                SR-238 HDDA       301º C                 7 min                    observed as above. When the            molecular weight between double
                SR-239 HDDMA       43º C                63 min                                                           bonds and, therefore, results in
                                                                                  moles of ethoxylation >3, however,                                                               Acrylates            > Methacrylates
                                                                                  the higher molecular weight and        higher elongation at break and
                                                                                  more flexible chain results in a       lower modulus.                                          Rubber Modulus
Figure 2. Plot of Peak Exotherm Temperature vs.                                                                                                                                    Methacrylates > Acrylates
          Monomer Ethoxylation                                                    lower glass transition temperature     Conclusions
                                                                                  and lower dynamic modulus.                                                                     Young’s Modulus
                         250                                                      This type of data is useful in         Sartomer’s broad range of
 Peak Temperature (ºC)

                                                                                                                                                                                   Methacrylates > Acrylates
                                                                                  determining application properties     monomers allows formulators
                                                                                  such as impact-resistance and
                                                                                  flexibility (Tg < ambient tempera-
                         100                                                      ture) or hardness (Tg > ambient).
                          50                                                      Mechanical Properties                                                                                            Table 6. Mechanical Properties for
                                                                                                                          Table 5. Mechanical Properties for                                                Ethoxylated Monomers
                           0                                                      Table 5 shows the elongation                     Acrylate vs. Methacrylate Monomers
                                                                                                                                                                                                         Monomer       Elongation           Young’s
                               0       5           10            15
                                   Ethoxylation number (n)
                                                                                  at break and Young’s Modulus            Monomer           Elongation                  Young’s                          (moles EO)     @ Break %         Modulus (MPa)
                                                                                  results for three different acrylate                      @ Break %                 Modulus (MPa)                      SR-206
                                                                                                                                                                                                                           0.5                 2800
                                                                                                                          SR-238 (HDDA)         0.6                       1600                           HDDA (n=1)
                                                                                  vs. methacrylate structures.            SR-239 (HDDMA)        0.7                       2100                           SR-231
                                                                                                                                                                                                                           0.6                 2400
                                                                                  In general, the elongation at           SR-351 (TMPTA)        1.1                       1100
                                                                                                                                                                                                         DEGDMA (n=2)
                                          mechanical properties at higher         break is higher for acrylates than      SR-350 (TMPTMA)       0.1                       3400
                                                                                                                                                                                                                           2.7                 2000
                                                                                                                                                                                                         TEGDMA (n=3)
                                          temperatures. Since it is known         methacrylates. As expected, the         SR-610 (PEG600DA)     4.1                        26
                                          that the rubber modulus can be          elongation at break increases           SR-252 (PEG600DMA) 2.7                           23                            PEG200DMA (n=4)
                                                                                                                                                                                                                           2.5                 1500
                                          correlated to crosslink                 with rising molecular weight
                                          density and a higher crosslink          and decreasing functionality.
                                          density results in better thermal       Conversely, methacrylates                Figure 3. Plot of Modulus vs. Temperature                               Figure 4. Plot of Modulus vs.
                                          and chemical resistance, it can         generally exhibit greater modulus                                                                                          Monomer Ethoxylation
                                          be determined that methacrylates        than acrylates due to the presence                     1010                                                                  1010
                                          offer better thermal- and chemical-     of the methyl group. Young’s                                                    SR239 – HDDMA

                                          resistance properties. It is believed   Modulus can be correlated to the
                                                                                                                                                                  SR238 – HDDA
                                                                                                                            E (cO)[Pa]

                                          that the presence of the methyl                                                                                                                                                                             n=2

                                                                                                                                                                                                   E (A)[Pa]
                                                                                  crosslink density. Therefore, lower                      9

                                          group strengthens and rigidifies                                                               10
                                                                                  molecular weight and higher                                                                                                                                         n=4.1
                                          the structure above its glass


                                                                                  functionality monomers exhibit                                                                                               108
                                          transition temperature.                 higher modulus values.                                                                                                                                              n=13.2

                                                                                                                                         10                                                                    107
                                                                                                                                          -100.0   -50.0   0.0   50.0 100.0 150.0
                                                                                                                                                                                                                 -100.0 -50.0   0.0 50.0 100.0 150.0
                                                                                                                                                           Temp (ºC)
                                                                                                                                                                                                                                Temp (ºC)

                  9                                                                                                                                                                                                                               10
     SMA® Resin Additives For Low-Gloss                                               Table 7. Typical Formulations for Hybrid Powder Coatings

     Hybrid Powder Coatings                                                                Type
                                                                                                                                       Hybrid Formulation
                                                                                                                                       (Using Active Resin)
                                                                                                                                                                                Hybrid Formulation
                                                                                                                                                                                 (Catalyst Added)
                                                                                           Epon 2002
                                                                                           (Resolution Performance        79                        32.5                                     32.5
                                                                                            Products Epoxy Resin)

     The ability to control the surface       protection (non-yellowing)                   Catalyzed
     gloss of a powder-coated article         in white pigmented coated
     enables its use in a wide range          formulations.                                Polyester
     of functional and decorative             SMA resin grades include SMA                 SMA 3000P
                                                                                                                          16                        6.6                                      6.5
     applications. Unmodified resins –        3000, 2625, 3840, and 1440.
                                                                                           (Sartomer Company)

     used in most powder coating              Use of the different grades gives
                                                                                           (Solutia Leveling Agent)
     classes – level and cure to give a       control over surface appearance.             Carbon Black                   1.6                       1.3                                      1.3
     high-gloss surface.                      For example, coarseness of texture           CG-1200
     However, if a low-gloss or matted        and some control over coating cure           (Air Products DICY)

     surface appearance is desired, this is   temperature is achieved. The SMA             Huberbrite #1
                                                                                                                                                     26                                      25.8
                                                                                           (J. M. Huber BaSO4)
     typically achieved by formulating        resin should be added as 1 to 10
                                                                                           Resiflow P-67
     additives into the powder coating.       weight % of the total powder coat-                                                                    0.8                                      0.8
                                                                                           (Estron Leveling Agent)

     For many years, SMA® resins have         ing formulation. A typical low-gloss         Benzoin                                                  0.3                                      0.3
     been successfully used as an addi-       epoxy powder coating formulation             Tetra Butyl-
     tive to prepare low-gloss epoxy          is given in Table 7.                         Phosphium                                                                                         0.3
     powder coating formulations.             Epoxy-Polyester Hybrid                       60º Gloss                       3                         11                                       17
     Now, new SMA-based low-gloss             Powder Coating Formulations
     epoxy polyester hybrid formula-
     tions have been developed.               Hybrid, powder coating formula-
                                              tions, containing both epoxy resin      more effective gloss-reducing                   1) Use a polyester resin
     Epoxy Powder-Coating                     and carboxy terminated polyester        additives in hybrid formulations                   manufactured to contain
     Formulations                             resin, are widely used due to their     than are the SMA resin partial                     the catalyst. Many such
                                              low cost and excellent combination      ester grades.                                      resins are available, and are
     SMA resins are a family of low
                                              of properties. The presence of two                                                         sold as high reactivity, active,
     molecular weight, styrene maleic                                                • Using an excess of epoxy resin
                                              types of resin in the formulations                                                         or low-temperature curing
     anhydride copolymers and their                                                    relative to what would be used
                                              requires a more complicated                                                                polyester resins. Or,
     partial esters. When SMA resins                                                   in a non-SMA containing
     are added to a typical epoxy resin       curing chemistry when compared           formulation to fully cure the                  2) Add a catalyst during the pow-
     powder coating formulation, the          to pure epoxy resin formulations.        SMA anhydride functionality.                      der coating formulation. Phos-
     two resins react during the cure         Nevertheless, when simple formu-         For example, when a 70/30                         phonium salts, such as tetra
     cycle to give a uniform surface          lation guidelines are followed           polyester resin is used, formulate                butylphosphonium
     roughness with a unique low-gloss        SMA resins make highly effective         50 parts polyester resins with 50                 bromide, are particularly effec-
     appearance to the finished coating.      low-gloss additives in hybrid            parts epoxy resin; or when a                      tive catalysts and can
     With these additives, low gloss          powder coatings.                         60/40 polyester resin is used,                    be used at very low concen-
     values can be achieved (<10 mea-         Hybrid, low-gloss powder coatings        formulate with 40 parts polyester                 trations (0.25-0.50 wt.%
     sured at 60º), as well as excellent      are prepared by:                         resin and 60 parts epoxy resin.                   of the total formulation).
     physical properties, including                                                  • Formulating so there is an                   • Cure the hybrid coatings at a
     solvent rub resistance, crosshatch       • Formulating with 5-10 weight
                                                % of SMA 3000. The anhydride           esterification catalyst present.               minimum of 400º F.
     adhesion, and pencil hardness.                                                    This can be done by one of
     In addition, the SMA additive              functionalized SMA resins are                                                       * For the full version of this article, please fill out and
                                                                                       two simple methods:                            return the reply card.
     tends to give good overbake

11                                                                                                                                                                                                   12
            Refractive Index in Coating Formulations

              When formulating UV-curable              against those with bisphenol A
              coatings, inks, and other materials,     – or a phenoxy ring structure –              New Technical Resources
              it is important to take into account     in the backbone.
              the refractive indexes (RI) of the
                                                       Functionality                          Along with tailor-made products,
              monomers and oligomers. RI,
              often described as the bending           Functionality also plays a role in     Sartomer offers fast chemist-to-
              of light, relates to the change in       determining the RI of monomers         chemist communication, training
              direction of light rays passing          and oligomers, as monomers with        seminars, and technical informa-
              from one medium to another of            high functionality generally have      tion retrieval.                        Interactive Web Site
              different density, as from air to        high RIs. For example, pentafunc-
                                                                                              Technical Hotline                      Sartomer Company’s interactive
              water or glass.                          tional monomers have higher RIs
                                                                                              800-949-6544 or                        Web site – –
                                                       than similar products with lower
              This phenomenon occurs when                                                     610-363-4198                           is designed to help formulators
              light travels through one material                                              Sartomer’s dedicated technical         search for specialty chemicals
              and strikes a material of lower          However, structure plays a bigger      hotline service enables coating        with the right performance
              refractive index. When this hap-         role than functionality in determin-   formulators to speak with technical    characteristics to meet the needs
              pens, the light is bent toward the       ing RI. For example, isobornyl         personnel directly. The technical      of their particular high-
              material of higher refractive index.     acrylate and isobornyl methacrylate    hotline provides immediate answers     performance applications.
              RI is an important element in            are monofunctional monomers –          about the applicability and proper
                                                       but they have a ring structure in                                             Visitors can search Sartomer’s
              coatings formulation because, in                                                use of Sartomer’s products.            full line of products, including
              general, the higher the refractive       the backbone. Consequently,
                                                       they have a relatively high RI         Technical Training Seminars            an extensive line of liquid and
              index of monomers and oligomers,                                                                                       metallic monomers, oligomers,
              the higher the gloss of the coating.     when compared to other mono-           Sartomer offers periodic technical
                                                       functional monomers.                                                          SMA®, Ricon®, Poly bd® and
              Also, higher RIs tend to result in                                              training seminars regarding
                                                                                                                                     hydrocarbon resins by product line,
              clearer films.                           Molecular Weight                       low-VOC coating systems at its
                                                                                                                                     name, code, application, or perfor-
                                                                                              corporate headquarters in Exton,
              Critical factors that affect the RI of   Given the same basic backbone                                                 mance property.
                                                                                              PA. The two-day course typically
              monomers and oligomers include           structure in monomers or               includes several co-supplier guest     Access data sheets, technical papers
              backbone structure, functionality,       oligomers, the higher the molecular    speakers. The course also includes a   and application bulletins that detail
              and molecular weight. The rela-          weight, the higher the RI. This is     product synthesis and applications     performance properties and recom-
              tionship between these factors and       seen in Sartomer's ethoxylated         laboratory tour. Please fill out the   mend the appropriate chemicals for
              refractive index is discussed below.     TMPTA series of monomers, as           enclosed postage-paid reply card to    your specific application.
              Backbone Structure                       well as in monomers with an            receive more information about
                                                       alkane backbone.                       upcoming seminars.
              Monomers and oligomers with ring
              structures tend to have a higher RI      The RIs of acrylates and methacry-                                            The information contained in this booklet is

              than straight chain monomers.            lates may also differ; acrylates                                              believed to be accurate. However, all recom-
                                                                                                                                     mendations are made without warranty, since
              This is evident when comparing           generally exhibit a lower RI than                                             the conditions of use are beyond Sartomer

              the RIs of straight chain monomers       the corresponding methacrylate.                                               Company’s control. The listed properties are
                                                                                                                                     illustrative only and are not product specifica-
                                                                                                                                     tions. Sartomer Company disclaims any liability
                                                                                                                                     in connection with the use of the information
                                                                                                                                     and does not warrant against infringement by
     Use reply card to request a copy of this complete paper                                                                         reason of the use of its products in combina-
                                                                                                                                     tion with other material or in any process.

13                                                                                                                                                                                      14
            Join Sartomer Company
            at Fall 2001 Trade Shows

Sartomer Company will feature its com-
plete line of monomers, oligomers, UV
photoinitiators, SMA®, Ricon®, Poly bd®
and hydrocarbon resins at several fall
2001 trade shows. These products are                      Join Sartomer and sister company
used to reduce volatile organic com-                      Cray Valley at the RadTech 2001
pound (VOC) air emissions in a wide                       Exhibition and Conference for UV/EB
variety of technologies for coatings,                     Curing at the Congress Centre in Basel,
paints, inks, composites, and adhesives.                  Switzerland from Oct. 8-10, 2001.
We invite you to visit us to discuss your                 For more info:
raw material and application needs.                       RadTech Europe
                                                          Phone:          +31 70 312 39 16
                                                          Fax:            +31 70 363 63 48

                                                          Join Sartomer at FSCT’s Annual
Join Sartomer at Composites 2001 at the                   Meeting and International Coatings
Tampa Convention Center in Tampa,                         Expo and Technology Conference at
FL from Oct. 3-6, 2001.                                   the Georgia World Congress Center
For more info:                                            in Atlanta, GA from Nov. 5-7, 2001.
Composites Fabricators Association                        For more info:
Phone:         703-525-0511                               Federation of Societies
Fax:           703-525-0743                               for Coatings Technology
Web:                              Phone:          610-940-0777
                                                          Fax:            610-940-0292

Oaklands Corporate Center
502 Thomas Jones Way
Exton, PA 19341
Phone:       610-363-4100
Toll Free:   800-SARTOMER
Fax:         610-363-4140
Responsible Care and hands logo are registered trademarks of the American Chemistry Council.

3043 9/01
                  I WANT TO KNOW MORE ABOUT CROSS-

    Please send me a free M-Cure® Reactive Modifiers for Amine-Cured
    Epoxy Resins brochure. Also, please send:                   (3952)
    __ Product Catalog (Monomers, Oligomers, Photoinitiators)            (3000)
    __ Oligomer Selection Guide                                          (3060)
    __ Sartomer Overview (Capabilities Brochure)                         (1010)
    __ SMA® Multifunctional Resins General Brochure
    __ Poly bd® Resins in Urethane Elastomers
    __ Ricon® Resins Product List

    Please send the following application information:
    __ The Influence of Monomers on the Performance
       Properties of Oligomers                                           (4304)
    __ Refractive Index and Product Selection                            (4007)
    __ A New pH-Neutral Waterborne Dispersing Resin for
       Metallic and Organic Pigments (SMA® Resins)                       (4950)

    Please contact me about my application.

    Please send information about upcoming technical training seminars.

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