UCAR
™
Solution Vinyl Resins
Flexible Solutions
for Coatings
Contents
UCAR™Solution Vinyl Resins for Coatings 3
Typical Properties Table 4
Applications Table 6
General Characteristics Table 6
FDA Status 7
Vinyl Chloride/Vinyl Acetate Copolymers 8 Carboxyl-Modified Vinyl Chloride/Vinyl
Acetate Copolymers 9
Epoxy-Modified Vinyl Chloride/Vinyl
Acetate Copolymers 9
Hydroxyl-Modified Vinyl Chloride/Vinyl
Acetate Copolymers 10
Hydrolyzed Resins 10
Directly Polymerized Resins 10 Carboxyl Modified/Hydroxyl Modified Vinyl Chloride/Vinyl Acetate Copolymer 11 Sulfonate Modified Copolymer 11 Solution Vinyl Resins for VOC-Compliant
Coatings–Water-based Resin 12
Solutions 12
Viscosity Behavior 22
Application Methods 23
Solution Preparation 23
Formulation of Clear Coatings 25
Plasticizers 25
Heat Stabilizers 25
Light Stabilizers 26
Formulation of Pigmented Coatings 27 Modification with Other Polymers 30
Compatibility 30
Reactive (Crosslinking) Systems 30
Adhesion 32
Where Not to Use Vinyl Coatings 32
UCAR
™Solution Vinyl Resins for Coatings
Through advanced solution vinyl resin
technology, Dow has successfully extended
the 50 years of proven performance of the
vinyl chloride backbone.
UCAR™Solution Vinyl Resins are available in
four general copolymer types: ■ Vinyl Chloride/Vinyl Acetate
■ Carboxyl-Modified Vinyl Chloride/Vinyl Acetate
■ Epoxy-Modified Vinyl Chloride/Vinyl Acetate ■ Hydroxyl-Modified Vinyl Chloride/Vinyl
Acetate
These copolymers are available as powders and solutions in a range of molecular weights and compositions.
Coatings based on these resins are nonoxidizing and permanently flexible, and are characterized by the absence of color, odor, and taste. They are not attacked at normal temperatures by dilute alkalies or mineral acids, alcohols, greases, oils, or aliphatic hydrocarbons. They have a low moisture-vapor transmission rate, low order of water absorption, and are tough and durable. The molecular weight and the ratio of vinyl chloride to vinyl acetate affect the solubility and other physical properties of the resin. As the molecular weight (degree of polymerization) is increased, the solution viscosity increases and the strength of the film increases. Vinyl chloride contributes film strength and toughness, as well as water and chemical resistance. Vinyl acetate improves solubility and film flexibility.
When properly pigmented, coatings based on vinyl chloride/acetate copolymers have excellent outdoor durability. Hydroxyl-modification improves compatibility and adhesion, and provides a site for crosslinking. Carboxyl modification permits formulation of coatings that will adhere to clean metal surfaces on air-dry. Epoxy modification provides the ability to crosslink with carboxyl-modified vinyl resins to give an all-vinyl reactive system that yields thermoset-like characteristics, most notably improved toughness, enhanced physical properties, and superior chemical resistance. UCAR™Solution Vinyl Resins, produced by a
proprietary solution polymerization process, offer several advantages:
High Purity
No water-soluble suspending agents or surfactants are used in the manufacture; therefore, water resistance is outstanding. Additionally, the as-received vinyl chloride monomer (VCM) content of dry vinyl powders is nondetectable.
Uniform Polymer Composition and Narrow Molecular Weight Distribution
Provide predictable solution viscosities and batch-to-batch production uniformity.
Low in Gels
Easily dissolved and low in gels and insoluble materials.
Compatibility
All UCAR™Solution Vinyl Resins are completely
compatible with each other and many different types of resins.
Recoatable
Typically dry by evaporation. Hydroxyl-modified vinyls can be cured by crosslinking.
Polymer Composition % by Wt
VCl 90 86 86 86 83 81
VAc 10 14 14 13 16 17
Other — — — 1a 1a 2a
Reactive Functionality
Type — — — carboxyl carboxyl carboxyl
% by Wt — — — 1.0 1.0 2.0
Acid No. — — — 10 10 19
Hydroxyl Value — — — — — —
Epoxy Equivalent Wt — — — — — —
Inherent Viscosity ASTM-D1243 0.74 0.50 0.40 0.50 0.38 0.32 Specific Gravity ASTM-D792 1.36 1.35 1.35 1.35 1.34 1.34
Glass Transition Temp. (Tg), °C 79 72 72 74 72 70
Average Molecular Wt, Mnb 44,000 27,000 22,000 27,000 19,000 15,000
Solution Viscositycat 25°C, cP 1300d 600 200 650 100 55
Typical Solution Properties
Solids, % by Wt 15 20 25 20 25 30
MEK/Toluene 67/33 50/50 33/67 50/50 25/75 25/75
Viscosity at 25°C, cP 250 200 175 150 250 370
UCAR™Solution Vinyl Resins
VYNS-3 VYHH VYHD VMCH VMCC VMCA
Table 1A-Typical Properties of UCAR
™Solution Vinyl Resins
†(a) Maleic acid
(b) Referenced to polystyrene standard. (c) 30% resin in MEK
(d) 20% resin in MEK
† The physical property data listed here are considered to be typical
Polymer Composition % by Wt
VCl 90 90 81 81 81 82 85
VAc 4 4 4 4 4 4 13
Other 6d 6d 15e 15e 15e 14a,e 2f
Reactive Functionality
Type hydroxyl hydroxyl hydroxyl hydroxyl hydroxyl hydroxyl/ sulfonate carboxyl
% by Wt 2.3 2.3 1.8 1.9 2.0 2.0 1.0
Acid No. — — — — — — —
Hydroxyl Value 76 76 59 63 66 59 —
Epoxy Equivalent Wt — — — — — — —
Inherent Viscosity ASTM-D1243 0.53 0.44 0.56 0.44 0.30 0.56 0.33 Specific Gravity ASTM-D792 1.39 1.39 1.37 1.36 1.37 1.37 1.35
Glass Transition Temp. (Tg), °C 79 77 70 65 65 72 72
Average Molecular Wt, Mnj 27,000 22,000 33,000 24,000 15,000 35,000 17,000
Solution Viscositykat 25°C, cP 1,000 400 930 275 70 720 850
Typical Solution Properties
Solids, % by Wt 20 25 20 30 30 20 20
MEK/Toluene 50/50 50/50 50/50 50/50 25/75 50/50 50/50
Viscosity at 25°C, cP 350 400 171 184 340 170 500
UCAR™Solution Vinyl Resins
UCARMAG™Binder
VAGH VAGD VAGF VAGC VROH 527 569
Table 1B–Typical Properties of UCAR
™Solution Vinyl Resins
†(a) Maleic acid (d) Vinyl alcohol (e) Hydroxyalkyl acrylate (f) Sulfonate-containing monomer (j) Referenced to polystyrene standard. (k) 30% resin in MEK
† The physical property data listed here are considered to be typical
UCAR™Solution Packaging General Marine and Magnetic Strippable Wood
Vinyl Resin Food Non-Food Metals Maintenance Media Inks Adhesives Coatings Finishes
VYNS-3 ■ ■ ■ ■ ■ VYHH ■ ■ ■ ■ ■ ■ VYHD ■ ■ ■ ■ VMCH ■ ■ ■ ■ ■ VMCC ■ ■ ■ ■ ■ VMCA ■ ■ ■ ■ ■ VAGH ■ ■ ■ ■ ■ ■ ■ VAGD ■ ■ ■ ■ ■ VAGF ■ ■ ■ ■ ■ ■ ■ VAGC ■ ■ ■ ■ ■ ■ VROH ■ ■ ■ ■ UCARMAG™ Binder 527 ■ 569 ■ ■
Appearance White powder
Particle Size
% by wt, min, through 20 mesh 98 Bulk Density, lb/ft3 24 to 34
Heat Loss, % by wt, max 3.0 Water Content, % by wt, max 0.5 Melting Point, °C 93 to 135
Applications and Characteristics
Table 2–Applications
Table 3—General Characteristics of
FDA Regulation Use UCAR™Solution Vinyl Resin
21CFR 175.105 Components of adhesives used in articles intended VYHD, VYHH, VYNS-3, for packaging, transporting, or holding food. VMCA, VMCC, VMCH,
VAGD, VAGH
21CFR 175.300 Components of resinous and polymeric coatings VYHD, VYHH, VYNS-3, (b)(3)(XV) to be applied as continuous films to food-contact VMCA, VMCC, VMCH,
surfaces of articles intended for use in processing, VAGD, VAGH manufacturing, packing, producing, heating,
packaging, holding, or transporting food.
21CFR 175.320 Components of a coating that is applied as a VYHD, VYHH, VYNS-3, continuous film over one or both sides of a base VMCA, VMCC, VMCH, film produced from one or more of the basic olefin VAGD, VAGH
polymers complying with 177.1520.
21CFR 176.170 (b) Components of the food-contact surface of paper VYHD, VYHH, VYNS-3, and paperboard used to package aqueous and VMCA, VMCC, VMCH,
fatty foods. VAGD, VAGH
21CFR 176.180 Components of paper and paperboard in contact VYHD, VYHH, VYNS-3,
with dry food. VMCA, VMCC, VMCH,
VAGD, VAGH
21CFR 177.1210 Components of closures with sealing gaskets VYHD, VYHH, VYNS-3,
for food containers. VMCA, VMCC, VMCH,
VAGD, VAGH
(1) Since government regulations are subject to revision, it is the user’s responsibility to refer to the Code of Federal Regulations or the Federal Register to determine current regulatory status.
The UCAR™Solution Vinyl Resins listed below are cited in the following regulations1of the United States Food and Drug Administration (FDA) for use in food-contact applications, such as can, paper, film, and foil coatings, and coatings for closures.
Vinyl Chloride/Vinyl Acetate Copolymers
UCAR™VYNS-3 Solution Vinyl Resin
The highest molecular weight Solution Vinyl Resin, having a composition of approximately 90 percent vinyl chloride and 10 percent vinyl acetate, UCAR™VYNS-3 Solution Vinyl Resin is usually dissolved in relatively strong ketone systems to provide resin solutions of 13 to 17 percent solids. It is used where the ultimate toughness, durability, and chemical resistance are required. Because of its excellent tensile tear properties, UCAR™VYNS-3 Solution Vinyl Resin is ideally suited for strippable coatings
applications. UCAR™VYHH Solution Vinyl Resin is often blended with UCAR™VYNS-3 Solution Vinyl Resin to increase sprayable solids.
UCAR™VYHH Solution Vinyl Resin
A high molecular weight resin having a composition of approximately 86 percent vinyl chloride and 14 percent vinyl acetate, UCAR™ VYHH Solution Vinyl Resin offers a desirable balance of chemical resistance, solubility, film strength, and thermoplasticity. It is usually dissolved in a relatively strong solvent/diluent combination, such as ketone solvent/aromatic
diluent (50/50 percent by weight). With this system, a solids content of 20 to 22 percent can be achieved. Marine and maintenance coatings, ink and overlacquers for vinyl substrates, strippable coatings, and masonry and metal coatings are among the principal appli-cations for UCAR™VYHH Solution Vinyl Resin.
UCAR™VYHD Solution Vinyl Resin
A medium molecular weight resin having a composition of approximately 86 percent vinyl chloride and 14 percent vinyl acetate; UCAR™ VYHD Solution Vinyl Resin is more soluble in ketones and other solvents than UCAR™VYHH Solution Vinyl Resin and, therefore, has a greater tolerance for aromatic hydrocarbon diluents. Resin solutions of 25 percent solids can be achieved by dissolving UCAR™VYHD Solution Vinyl Resin in a system consisting of ketone solvent/aromatic diluent (35/65 percent by weight). UCAR™VYHD Solution Vinyl Resin can be substituted for UCAR™VYHH Solution Vinyl Resin in most applications where higher solids are needed.
Carboxyl-Modified
Vinyl Chloride/Vinyl Acetate Copolymers
The carboxyl-modified vinyl chloride/vinyl acetate copolymers are made specifically for the formulation of coatings having excellent adhesion to various substrates, especially metals, cellulosics, and certain plastics.
UCAR™VMCH Solution Vinyl Resin
A high molecular weight resin containing approx-imately 86 percent vinyl chloride, 13 percent vinyl acetate, and 1 percent maleic acid; UCAR™VMCH Solution Vinyl Resin is usually dissolved in relatively strong solvent/diluent combinations, such as 50 percent ketone/50 percent aromatic hydrocarbon, to produce solutions of 20 to 22 percent solids. UCAR™ VMCH Solution Vinyl Resin is used primarily for air-dry finishes, such as maintenance, marine, and metal coatings, and is often used to make heat-sealable packaging coatings.
UCAR™VMCC Solution Vinyl Resin
A medium molecular weight resin containing approximately 83 percent vinyl chloride, 16 percent vinyl acetate, and 1 percent maleic acid; UCAR™VMCC Solution Vinyl Resin is more soluble than UCAR™VMCH Solution Vinyl Resin in ketones, esters, and other solvents used to dissolve vinyl resins.
UCAR™VMCC Solution Vinyl Resin also has a higher tolerance for aromatic hydrocarbon diluents. When dissolved in a suitable solvent system, such as a 50 percent ketone/50 percent aromatic hydrocarbon, resin solutions of 23 to 25 percent solids can be achieved. UCAR™ VMCC Solution Vinyl Resin is often used in the same applications as UCAR™VMCH Solution Vinyl Resin. However, because of its better solubility, it is also used as an adhesion promoter for vinyl organosols in can coatings.
UCAR™VMCA Solution Vinyl Resin
A low molecular weight resin containing approximately 81 percent vinyl chloride, 17 percent vinyl acetate, and 2 percent maleic acid; UCAR™VMCA Solution Vinyl Resin is
characterized by a high degree of solubility in solvent systems having a high aromatic hydrocarbon content. When dissolved in a suitable solvent/diluent combination, such as 25 percent ketone/75 percent aromatic hydrocarbon, resin solutions of 30 percent solids can be achieved. UCAR™VMCA Solution Vinyl Resin yields the good balance of solubility and viscosity properties needed for high-build, air-dry
maintenance finishes. It can also be used in coatings and adhesives applications where higher solids are desirable.
Hydroxyl-Modified
Vinyl Chloride/Vinyl Acetate Copolymers
Hydroxyl-modified vinyl chloride/vinyl acetate copolymers are manufactured using two different processes. UCAR™VAGH and VAGD Solution Vinyl Resins are polymers made in a two-step process that yields vinyl alcohol in the backbone. The other hydroxyl-modified resins are produced by a one-step polymerization process similar to that used to make the copolymer and carboxy-functional solution polymerized resins described above.
Hydroxyl-modified vinyl chloride/vinyl acetate copolymers are noted particularly for
compatibility with other film-forming resins, such as alkyds, urethane elastomers, isocyanate resins, epoxy polymers, and urea and melamine resins. Hydroxyl-modified vinyls are, therefore, often formulated with these and other film-forming materials to improve coating properties, such as adhesion, flexibility, toughness, hardness, and chemical resistance. Hydroxyl-modified resins are often used to impart snap-dry properties to a coating. The hydroxyl
functionality permits crosslinking reactions for thermoset coating systems that exhibit outstanding chemical and water resistance. Coatings based on these resins also have good adhesion to wash primers, metals, wood, and many plastic substrates.
Hydrolyzed Resins
UCAR™VAGH Solution Vinyl Resin
A high molecular weight, partially hydrolyzed vinyl chloride/vinyl acetate resin having a composition of approximately 90 percent vinyl chloride, 4 percent vinyl acetate, with a hydroxyl content of approximately 2.3 percent; UCAR™ VAGH Solution Vinyl Resin can be dissolved in relatively strong solvent/diluent combinations, such as 50 percent ketone/50 percent aromatic hydrocarbon, to produce resin solutions of 20 percent solids. UCAR™VAGH Solution Vinyl Resin can be used for a wide range of coatings applications, including industrial maintenance and marine finishes, wood finishes, paper coatings, metal decorative and container coatings, and as a binder in magnetic tape.
UCAR™VAGD Solution Vinyl Resin
A medium molecular weight, partially hydrolyzed vinyl chloride/vinyl acetate resin having a
composition of approximately 90 percent vinyl chloride, 4 percent vinyl acetate, with a hydroxyl content of approximately 2.3 percent. The lower molecular weight provides improved solubility and permits the formulation of solutions containing higher solids.
Directly Polymerized Resins
UCAR™VAGF Solution Vinyl Resin
A high molecular weight copolymer comprised of vinyl chloride, vinyl acetate, and a hydroxyalkyl acrylate. The vinyl chloride portion is about 81 percent with the hydroxyl content at 1.8 percent. The solution viscosity and other properties of UCAR™VAGF Solution Vinyl Resin strongly resemble those of UCAR™VAGH Solution Vinyl Resin. UCAR™VAGF Solution Vinyl Resin can be used for a wide range of coatings
applications, including industrial maintenance and marine finishes, paper coatings, general metal finishes, and as a binder in magnetic tape.
UCAR™VAGC Solution Vinyl Resin
A medium molecular weight copolymer comprised of vinyl chloride, vinyl acetate, and a hydroxyalkyl acrylate. The vinyl chloride portion is about 81 percent with the hydroxyl content at 1.9 percent. The solution viscosity and other properties of UCAR™VAGC Solution Vinyl Resin are very similar to those of UCAR™ VAGD Solution Vinyl Resin. UCAR™VAGC Solution Vinyl Resin finds commercial
application in clear and pigmented coatings for metal, wood, paper, concrete, masonry, films, foils, fabrics, and leather.
UCAR™VROH Solution Vinyl Resin
A low molecular weight copolymer comprised of vinyl chloride, vinyl acetate, and a hydroxyalkyl acrylate. The vinyl chloride portion is
approximately 81 percent, and the hydroxyl content is approximately 2 percent. High tolerance for alcohols and aliphatic diluents broadens the usefulness of UCAR™VROH Solution Vinyl Resin. UCAR™VROH Solution Vinyl Resin can be dissolved in solvent/diluent combinations, such as 25 percent ketone/75 percent aromatic hydrocarbon, to produce resin solutions of 30 percent solids. Also, 35 percent resin solutions can be prepared with UCAR™ VROH Solution Vinyl Resin using Rule 66-type exempt solvent systems (for the wood coatings industry) containing as much as 30 percent by volume butanol. UCAR™VROH Solution Vinyl Resin can be used in a wide variety of clear and pigmented coatings for metal, wood, paper, film, foil, and fabric.
Carboxyl Modified/
Hydroxyl Modified
Vinyl Chloride/Vinyl
Acetate Copolymer
UCARMAG™527 Binder Resin
A high molecular weight copolymer comprised of vinyl chloride, vinyl acetate, a hydroxy-alkyl acrylate, and a carboxylated monomer. The vinyl chloride content is about 80 percent by weight and the hydroxyl content is about 1.8 percent. The molecular weight and physical properties of UCARMAG™527 Binder Resin are similar to those of UCAR™VAGF Solution Vinyl Resin. A carboxyl monomer in the UCARMAG™527 Binder Resin gives the copolymer excellent wetting and pigment dispersion properties and has made the resin especially useful in magnetic tape coatings containing neutral or basic pigments. Because of its unique functionality, UCARMAG™527 Binder Resin might also be considered as a binder for printing inks, paper coatings, and general metal finishes.
Sulfonate Modified
Copolymer
UCARMAG™569 Binder Resin
A medium molecular weight copolymer containing vinyl chloride, vinyl acetate, and a monomer with metal sulfonate functionality. The vinyl chloride of the copolymer is about 85 percent by weight. The sulfonate functional monomer provides the copolymer with
exceptional wetting characteristics which make it an excellent dispersing medium for high surface area pigments used in magnetic media
applications. Since the copolymer has excellent heat stability, it can be used in applications requiring high shear milling operations to disperse high surface area or highly porous pigments. UCARMAG™569 Binder Resin, because of its sulfonate functionality, may also be useful in other nonmagnetic media
applications where good dispersing capabilities are needed. For example, UCARMAG™569 Binder Resin is an efficient grinding vehicle for hard-to-disperse organic colors such as lithol rubine red. Color concentrates impart high gloss and tinting strength in inks and coatings.
UCAR™AW-875 Waterborne Vinyl Resin
Dispersion
Since their commercialization about 50 years ago, UCAR™Solution-Polymerized Vinyl Resins have become the standards for a wide range of coatings applications. UCAR™ AW-875
Waterborne Vinyl Resin dispersion has been developed for compliant waterborne coatings, adhesives, and inks. This waterborne resin dispersion utilizes a solution-polymerized vinyl resin backbone that has been chemically modified to allow dispersion in water.
Solution Vinyl Resins for
VOC-Compliant Coatings–
Water-based Resin
Solutions
Several criteria must be weighed in choosing solvents and diluents for UCAR™Solution Vinyl Resins: ■ Solvent Strength ■ Volatility ■ Toxicity ■ Odor ■ Cost ■ Flammability ■ Type of Application
UCAR™Solution Vinyl Resins are readily dissolved into clear solutions at room temperature by ketones, nitroparaffins, esters, and chlorinated hydrocarbons. In general, ketones are the most suitable solvents for vinyl resins. Compared to other solvents, ketones yield higher resin concentrations without gelling and lower solution viscosities at equivalent solids content. Because of their solvency, they tolerate greater dilution with economical hydrocarbon diluents and exhibit better storage stability. Figure 1 compares the solvent strength of different ketones for UCAR™VYHD Solution Vinyl Resin.
Esters are useful in applications where minimal attack on the substrate is desirable (as with coatings on plastics). Because of their low solvency for vinyls, they should be used in combination with other active solvents.
Urethane-grade esters are preferred for minimum viscosity and optimum viscosity stability. Figure 2 compares the solvent strength of different esters for UCAR™VYHD Solution Vinyl Resin.
Figure 1–Viscosity vs. Concentration of UCAR
™VYHD Solution Vinyl Resin in Ketones
NOTE: Viscosity was determined using a Brookfield viscometer model RVT, running at 50 or 100 rpm with spindles #2 through #5, selected as appropriate for the solution being tested.
10,000 8,000 6,000 5,000 4,000 3,000 2,000 1,000 800 600 500 400 300 200 100 80 60 50 40 30 20 10 V iscosity at 25 ϒC, cP
Solids, percentage by weight
0 1 0 2 0 3 0 4 0 5 0
Isophorone
Cyclohexanone Methyl Isobutyl Ketone
Acetone Methyl Ethyl Ketone
NOTE: Viscosity was determined using a Brookfield viscometer model RVT, running at 50 or 100 rpm with spindles #2 through #5, selected as appropriate for the solution being tested.
Figure 2–Viscosity vs. Concentration of UCAR
™VYHD Solution Vinyl Resin in Esters
10,000 8,000 6,000 5,000 4,000 3,000 2,000 1,000 800 600 500 400 300 200 100 80 60 50 40 30 20 10 Vi sco sity at 25 ϒC, cP
Solids, percentage by weight
0 5 10 15 20 25 30 35
Methyl PROPASOL™ Acetate Isopropyl Acetat e Butyl Acetate Ethyl Acetate
Table 4–Solution Viscosity of UCAR
™VYHH Solution Vinyl
Resin in Ketones and Ketone/Aromatic Blends
Solution Viscosity at 25°C, cP
Ketone Solvent Formula A Formula B
Acetone 84 88
Methyl Ethyl Ketone 86 130
Methyl Propyl Ketone 124 212
Methyl Isobutyl Ketone 230 360
Methyl Isoamyl Ketone 304 504
Methyl n-Amyl Ketone 316 684
Cyclohexanone 672 360
Isophorone 930 484
Formulation Formula A Formula B
UCAR VYHH Solution Vinyl Resin 20 20
Ketone Solvent 80 40
Xylene — 20
Toluene — 20 Parts by Weight 100 100
NOTE: Viscosity was determined using a Brookfield viscometer model RVT, running at 50 or 100 rpm with spindles #2 through #5, selected as appropriate for the solution being tested.
Diluents lower coating costs, alter the
evaporation rates, and provide other important coating characteristics. Typical diluents for use with UCAR™Solution Vinyl Resins include aromatic hydrocarbons, such as toluene and xylene. Aliphatic hydrocarbons, such as mineral spirits, VM&P naphtha, and heptane can also be used. These aliphatic hydrocarbons are less effective than aromatic hydrocarbons and should be used at levels not exceeding 10 percent of the solvent blend.
Ketones tolerate greater amounts of aromatic diluents than do the ester solvents. Table 4 compares the viscosity of UCAR™VYHH Solution Vinyl Resin in ketones with the viscosity in ketone/diluent mixtures.
Optimum formulation stability and the lowest solution viscosities are obtained when the solvent system contains only active solvents. As the proportion of diluent increases, the stability declines. Figures 3 to 5 compare the solution viscosity of UCAR™Solution Vinyl Resins versus solids content in methyl ethyl ketone and in a methyl isobutyl ketone/toluene (50/50) blend. Formulating at excessively high solids or with weak solvent mixtures can result in solutions having unstable viscosities and can even lead to the formation of gel structures. As the molecular weight of the vinyl resin decreases, however, the diluent level can be increased while maintaining the same level of viscosity.
Figure 3–Viscosity vs. Concentration of Vinyl Chloride/Vinyl Acetate
Copolymers in Methyl Ethyl Ketone
NOTE: Viscosity was determined using a Brookfield viscometer model RVT, running at 50 or 100 rpm with spindles #2 through #5, selected as appropriate for the solution being tested.
10,000 8,000 6,000 5,000 4,000 3,000 2,000 1,000 800 600 500 400 300 200 100 80 60 50 40 30 20 10 Vi sco sity at 25 ϒC, cP
Solids, percentage by weight
0 1 0 2 0 3 0 4 0 5 0
VYNS-3 VYHH VYHD
Figure 3A–Viscosity vs. Concentration of Vinyl Chloride/Vinyl
Acetate Copolymers in Methyl Isobutyl Ketone/Toluene (50/50)
NOTE: Viscosity was determined using a Brookfield viscometer model RVT, running at 50 or 100 rpm with spindles #2 through #5, selected as appropriate for the solution being tested.
10,000 8,000 6,000 5,000 4,000 3,000 2,000 1,000 800 600 500 400 300 200 100 80 60 50 40 30 20 10 Vi sco sity at 25 ϒC, cP
Solids, percentage by weight
0 1 0 2 0 3 0 4 0 5 0
VYNS-3 VYHH VYHD
Figure 4–Viscosity vs. Concentration of Hydroxyl-Modified
Copolymers in Methyl Ethyl Ketone
NOTE: Viscosity was determined using a Brookfield viscometer model RVT, running at 50 or 100 rpm with spindles #2 through #5, selected as appropriate for the solution being tested.
10,000 8,000 6,000 5,000 4,000 3,000 2,000 1,000 800 600 500 400 300 200 100 80 60 50 40 30 20 10 Vi sco sity at 25 ϒC, cP
Solids, percentage by weight
0 1 0 2 0 3 0 4 0 5 0 VAGH VAGF VAGD VROH VAGC
Figure 4A–Viscosity vs. Concentration of Hydroxyl-Modified
Copolymers in Methyl Isobutyl Ketone/Toluene (50/50)
NOTE: Viscosity was determined using a Brookfield viscometer model RVT, running at 50 or 100 rpm with spindles #2 through #5, selected as appropriate for the solution being tested.
10,000 8,000 6,000 5,000 4,000 3,000 2,000 1,000 800 600 500 400 300 200 100 80 60 50 40 30 20 10 Vi sco sity at 25 ϒC, cP
Solids, percentage by weight
0 1 0 2 0 3 0 4 0 5 0 VAGH VAGF VAGD VROH VAGC
Figure 5–Viscosity vs. Concentration of Carboxyl-Modified
Copolymers in Methyl Ethyl Ketone
NOTE: Viscosity was determined using a Brookfield viscometer model RVT, running at 50 or 100 rpm with spindles #2 through #5, selected as appropriate for the solution being tested.
10,000 8,000 6,000 5,000 4,000 3,000 2,000 1,000 800 600 500 400 300 200 100 80 60 50 40 30 20 10 Vi sco sity at 25 ϒC, cP
Solids, percentage by weight
0 1 0 2 0 3 0 4 0 5 0
VMCH
VMCA VMCC
Figure 5A–Viscosity vs. Concentration of Carboxyl-Modified
Copolymers in Methyl Isobutyl Ketone/Toluene (50/50)
NOTE: Viscosity was determined using a Brookfield viscometer model RVT, running at 50 or 100 rpm with spindles #2 through #5, selected as appropriate for the solution being tested.
10,000 8,000 6,000 5,000 4,000 3,000 2,000 1,000 800 600 500 400 300 200 100 80 60 50 40 30 20 10 Vi sco sity at 25 ϒC, cP
Solids, percentage by weight
0 1 0 2 0 3 0 4 0 5 0
VMCH
VMCA VMCC
Figure 6–Memory Effect of Vinyl Resin Solutions
Viscosity Behavior
Viscosity behavior of vinyl solutions is influenced by resin concentration, active solvent used, ratio of solvent to diluent, and solution temperature. Viscosity changes in vinyl solutions are the result of different equilibrium effects that occur during the preparation and storage of resin solutions. The formation of a slight degree of micro-crystallinity among adjacent polymer molecules in solution is responsible for the observed viscosity increase.
The time required to reach equilibrium viscosity for vinyl resin solutions is influenced by resin molecular weight, solids content, solvent strength, processing time, and temperature. Vinyl resin solutions usually increase in viscosity with time. The extent of the total increase can range from a minor viscosity drift to a major change, such as gelation. Vinyl solutions that have gelled because of excessive solids content or a solvent mix that is too weak can be restored to fluidity by proper thinning and mixing.
Another equilibrium condition that affects solution viscosity is the memory effect. It is noted in vinyl solutions that have been subjected to increases or decreases in temperature and is characterized by a significant lag in the rate at which a vinyl solution returns to equilibrium viscosity after a temperature change. For example, a vinyl solution that has been heated will maintain an abnormally low viscosity for extended periods after it has returned to its initial temperature. This viscosity change is caused by differences in the degree of microcrystallinity of the solution at various temperatures. As the temperature increases, the degree of microcrystalline regions that exist in the solution decreases and the viscosity decreases. The memory effect is illustrated in Figure 6.
Formulators must be aware of both these effects and the time required to reach equilibrium conditions, so that viscosity stability problems, resulting from the preparation of solutions at
Vi sco sity Time (weeks) 0 1 2 3 4 5 Cooled Heated Room Temperatur e
Application Methods
Coatings based on UCAR™Solution Vinyl Resins may be readily applied by commonly used application methods, such as brushing, spraying, dipping, and roller coating. Of major
considertion for all applications is the correct consistency of the coating and proper
evaporation rate of the solvent used in a particularapplication method. Table 5 shows the properties of solvents useful with UCAR™ Solution Vinyl Resins.
Paper and cloth coatings may be formulated with highly volatile solvents, such as acetone and methyl ethyl ketone. Application by roller coaters requires solvents and diluents with a slow evaporation rate. Isophorone is used for roller coating because it is an excellent solvent for vinyls and has a slow evaporation rate. Methyl PROPASOL™Acetate and
Cyclohexanone Solvents are used for brush applications because they are slow-evaporating solvents that promote ease of application and good flow-out.
Solution Preparation
Use a high-shear mixer to prepare solutions of UCAR™Solution Vinyl Resins. Slow-speed, paddle-type agitators are not as effective as high-shear mixers. Equip the mixers with tight-fitting covers.
Add the solvent/diluent mixtures to the high-shear mixer. As the solvent mixture is agitated, add the resin slowly. The resin must be added slowly or lumping may occur.
UCAR™Solution Vinyl Resins should not be
charged into equipment containing flammable liquid or vapor unless precautions are taken to eliminate static electrical discharge (see Storage and Handling guide for UCAR™Solution
Vinyl Resin.)
As an alternate procedure, slurry the vinyl resin in a solvent/diluent blend containing about 20 percent of active solvent. Add the resin slowly. When all the resin is thoroughly wetted, vigorously agitate the slurry and slowly add the remaining portion of the active solvent.
Do not slurry the vinyl resin in the diluent alone; slurrying with diluents may produce a static electrical discharge and cause a flash fire. Follow all precautions for the safe handling of organic solvents and diluents.
High-shear mixing will heat solutions, especially viscous solutions. Maintain the solution
temperature as low as possible. If solutions are held at elevated temperatures for long periods of time, discoloration may result.
The addition of about 1.0 to 2.0 percent ERL-4221 cycloaliphatic epoxide†on resin will help control discoloration without affecting coating performance. For maximum stability, vinyl resin solutions should be stored in baked phenolic-lined containers.
†Note: ERL-4221 cycloaliphatic epoxide does not have FDA clearances for
Relative
Evaporation Weight Flash Point,
Rate Solubility per gallon Distillation Closed Solvents (BuAc=100) with VYHHa,b at 20°C, lb Range, °C Cup, °F
Fast Evaporating
Acetone 1160 S 6.59 56-57 0
Ethyl Acetate, 99% 615 S 7.51 76-78 30
Methyl Ethyl Ketone 570 S 6.71 78-81 24
Isopropyl Acetate, 99% 500 S-G 7.26 86-90 42
Propyl Acetate 275 S 7.39 99-103 58
Medium Evaporating
Methyl Isobutyl Ketone 165 S 6.67 114-117 61
Isobutyl Acetate, Urethane Grade 145 S 7.25 112-117 62
Butyl Acetate, Urethane Grade 100 S 7.34 124-129 84
Slow Evaporating
Amyl Acetate, Primary 42 S 7.29 140-150 101
Cyclohexanone 23 S 7.89 156 111
Methyl PROPASOL™Acetate Solvent 34 S 8.09 146 114
Diisobutyl Ketone 18 S-G 6.72 163-173 120
Diacetone Alcohol 14 S 7.82 145-172 133
Isophorone 3 S 7.67 210-218 179
Table 5–Solvents for UCAR
™Solution Vinyl Resins
(a) 0.5g VYHH to 4.5ml solvent (b) S = Soluble
Formulation of Clear Coatings
Clear vinyl coatings can be modified with plasticizers, heat and light stabilizers, and other materials for specific performance properties. Before incorporating any modifier in the formulation, understand clearly how the modifier meets the demands of the application. Do not use clear vinyl coatings for applications that involve long-term exposure to ultraviolet light.
Plasticizers
The addition of a plasticizer in the coating formulation will enhance flexibility and help to minimize solvent retention in the film. The typical phthalate, adipate, citrate, epoxy, and phosphate plasticizers are compatible with UCAR™Solution Vinyl Resins. In general, compatibility decreases as the hydrocarbon nature of the plasticizer increases. Polymeric plasticizers are less efficient than monomeric plasticizers.
Other factors to consider in selecting plasticizers include solubility, volatility, the effect on outdoor durability, the need for low-temperature
flexibility, and suitability for contact with food. Certain citrates, epoxies, and phthalates are permitted under FDA regulations. Monomeric plasticizers are most commonly used, although the polymeric plasticizers are used to provide special film characteristics, such as low extractability or migration. Phosphate
plasticizers are generally not recommended for outdoor exposure because of poor light stability. When a bake cycle is required, the volatility of the plasticizer is particularly important. The plasticizer may volatilize sufficiently to lower the concentration below what was originally intended for the dried or cured formulation.
The optimum level of plasticizer for a formulation will depend upon the specific resin used and the performance property required by the application. To obtain equivalent degrees of flexibility, higher molecular weight resins require more plasticizer than lower molecular weight resins. Proportions of 10 to 25 parts plasticizer per 100 parts of resin are typically used.
Table 6 provides a list of plasticizers having good compatibility with UCAR™Solution Vinyl Resins.
Heat Stabilizers
As with all vinyl resins, UCAR™Solution Vinyl Resins are degraded upon prolonged exposure to heat. The degradation products include hydrogen chloride, which accelerates further resin
degradation and leads to the development of unsaturated polymer structures that can be easily oxidized. The result is embrittlement, loss of flexibility, and discoloration of the vinyl film. To minimize the degradation of vinyl films, add suitable heat stabilizers.
Baking at temperatures above 248ºF (120ºC) for more than five minutes will usually require a thermal stabilizer to avoid degradation of the film. The use of a tin mercaptide stabilizer (1 percent†) in combination with a liquid epoxy
resin, such as ERL-4221 cycloaliphatic epoxy resin, or diglycidyl ether of bisphenol A resin (3 to 5 percent†) gives the best results.
Do not use barium, cadmium, or zinc stabilizers with the carboxyl-modified vinyl resins; they tend to react with the carboxyl groups. Zinc stabilizers also tend to develop color quickly, especially in low plasticizer systems. Iron and zinc surfaces can accelerate decomposition and discoloration.
Table 6–Typical Plasticizers for
UCAR
™Solution Vinyl Resins
Type Product
Phthalate Diisooctyl Phthalate Diisodecyl Phthalate Butyl Benzyl Phthalate Butyl 2-Ethylhexyl Phthalate 2-Ethylhexyl Isodecyl Phthalate Citrate Acetyl Tributyl Citrate
Acetyl Triethyl Citrate Tributyl Citrate
Phosphate Tri(2-ethylhexyl) Phosphate Triphenyl Phosphate Tributyl Phosphate Epoxy FLEXOL™EPO Plasticizer
(Epoxidized soybean oil) FLEXOL™EP-8 Plasticizer
(2-Ethylhexyl epoxy tallate) FLEXOL™ LOE Plasticizer
(Epoxidized linseed oil) Polymeric Adipic Acid Polyester
Azelaic Acid Polyester Sebacic Acid Polyester Blown Castor Oil Blown Soybean Oil Blown Linseed Oil Miscellaneous Dibutyl Sebacate
Di(2-ethylhexyl) Sebacate Di(2-ethylhexyl) Azelate †on weight of vinyl resin
Light Stabilizers
An adequate quantity of a hiding pigment will screen out incident radiation and prove the best light stabilizer for pigmented vinyl coatings. Do not use unpigmented vinyl coatings outdoors. Where only limited ultraviolet light exposure will be encountered, clear films should be formulated with a light stabilizer system to prevent
discoloration. The best light stabilizer system includes an ultraviolet light absorber (substituted benzophenones), a hindered amine light stabilizer (HALS), and ERL-4221 cycloaliphatic epoxy resin.
A typical system would be comprised of the following:
Ingredients %†
UV Absorber1 1
HALS2 2
ERL-4221 cycloaliphatic epoxy resin 3 †on weight of vinyl resin
(1) UV Absorber–Uvinul D-5O (BASF), Tinuvin 327 or 328 (Ciba Geigy) or equivalent.
(2) HALS–Tinuvin 292 (Ciba Geigy) or equivalent.
In all cases, choose stabilizers carefully and test them under actual use conditions. Consult suppliers of stabilizers for specific recommendations.
Formulation of Pigmented Coatings
Pigments are selected for hiding power, ultraviolet protection, purity, and ease of wetting. Although most commercially available pigments are suitable for use with UCAR™Solution Vinyl Resins, there are some general constraints. Additionally, there are specific constraints that apply to UCAR™Carboxyl-Modified Solution Vinyl Resins.
Do not use natural iron oxide pigments with any UCAR™Solution Vinyl Resin. These pigments contain trace impurities that can gel the coating or cause discoloration or excessive chalking of the film. Do not use iron-containing pigments, such as Prussian blue or the so-called “chrome greens” (blends of Prussian blue and lead chromate). Chromium oxide green, however, performs well with UCAR™Solution Vinyl Resins.
When an iron oxide pigment is desired, use synthetic iron oxides; they perform well with UCAR™Solution Vinyl Resins. With coatings containing synthetic iron oxides, use a heat stabilizer, particularly when bake temperatures may reach 248ºF (120ºC).
Gold bronze metallic pigments are powdered alloys of copper and zinc. They tend to react with vinyl, causing color development and gellation. When used to make gold inks, the powder is stirred into the ink vehicle shortly before use, and quantities sufficient for the job at hand are prepared.
There is a minimum amount of pigment that must be used to impart opacity to ultraviolet light. For example, about 65 parts of titanium dioxide (TiO2) per 100 parts of vinyl resin is the minimum amount that should be used. To obtain maximum hiding power in thin films, about 125 parts TiO2per 100 parts of vinyl resin is a practical maximum concentration.
Exceeding this level can cause excessive chalking. If color pigments are desired, they can generally be substituted for TiO2at an equal volume replacement. There are exceptions—ultra-fine particle size pigments, for example, are used at much lower concentrations.
The use of extender pigments or fillers will help improve the economics of the formulation. They will also help prevent sagging of thick wet films on vertical surfaces, will help control gloss (flatting) at low levels, and will permit greater film thickness per coat. Talcs, clays, barytes, and silicas may be used as extender pigments. If they are used, they will contribute little to ultraviolet absorption. A sufficient quantity of ultraviolet-light-absorbing prime pigment must be included in the formulation.
Table 7 provides a listing of pigment types and loadings typically recommended for UCAR™ Vinyl Copolymer and Hydroxyl-Modified Vinyl Resins.
Formulation with UCAR™VMCH, VMCC, and VMCA Carboxyl-Modified Solution Vinyl Resins involves special considerations. The carboxyl groups of these products are randomly spaced along the polymer chain and will react with basic materials to form irreversible gels or increased consistency of pigment-vinyl combinations. Do not use basic pigments, extenders, or fillers with UCAR™
Carboxyl-Modified Solution Vinyl Resins. Particularly, avoid lead-containing pigments (red lead, chrome yellow, chrome orange), zinc dust or zinc oxide, strontium-containing pigments, and calcium carbonate. Do not even use small amounts of these basic materials in pigment blends. With minor proportions of basic pigments, viscosity aberrations may not be predictable; some batches may have a normal viscosity and others will gel. Table 8 lists pigments typically used with UCAR™ Carboxyl-Modified Solution Vinyl Resins.
Table 7–Typical Pigments for UCAR
™Vinyl Copolymer
and Hydroxyl-Modified Solution Vinyl Resins
Parts perPigment 100 Parts Resin
Red
Pigment Scarlet —†
Permanent Red 2B
(Non-Resinated Calcium, Barium,
or Strontium Lakes of 2-B Acid —
BON Reds — Pyrazolone Reds — Indanthrene Reds — Quinacridone Reds — Perylene Scarlet — Pyranthrone Scarlet — Perylene Vermillion —
Iron Oxide, Synthetic Types 55 to 100
Yellow
Nickel-Titanium Yellow —
Indanthrene Types —
Benzidines —
Nickel Azo Types —
Flavanthrone —
Anthrapyrimidine —
Pyratex Yellows —
Iron Oxide, Synthetic Types 55 to 100
Orange Vat Orange — Dianisidine Orange — Benzidine Orange — Anthanthrone — Green Phthalocyanine Green 15 to 25
†— indicates that the minimum level of pigment to prevent ultraviolet light degradation has not been established.
Parts per
Pigment 100 Parts Resin
Maroon Thioindigo Types — Alizarine Types — BON Types — Perylene Maroon — Brown
Iron Oxide, Synthetic Types 55 to 100
Black
Carbon Black 5 to 7
Furnace Black 5 to 7
Lampblack 5 to 7
Iron Oxide, Synthetic Types 55 to 100
White Antimony Oxide — Titanium Dioxide 75 to 125 Zinc Oxide — Violet Carbazole — Carbozole Dioxane — Metallic Aluminum Pastes (65%) Leafing or Non-Leafing 60 to 85 Blue Phthalocyanine Blue —
Table 8–Typical Pigments for UCAR
™Carboxyl-Modified Solution Vinyl Resins
Parts perPigment 100 Parts Resin
Aluminum Powder 35 to 50 Titanium Dioxide 75 to 125 Phthalocyanine Green (Non-Resinated) 15 to 30 Phthalocyanine Blue (Non-Resinated) 15 to 30 Carbon Black 7
Iron Blue Chalks badly
Iron Oxide Yellow, Synthetica 60 to 125 Iron Oxide Red, Synthetica 60 to 125 Iron Oxide Black, Synthetica 60 to 125 Iron Oxide Brown, Synthetica 60 to 125
Ultramarine Blue Chalks and fades
Zinc Phosphate 75
Talc Use as filler
Clay or extender
Barytes pigments
If water is present in a pigmented coating containing a carboxyl-modified vinyl, the water molecule may form a bridge between the polymer’s carboxyl group and the pigment surface. Silica and alumina hydrate are prone to bridging or hydrogen bonding. Since most chloride-process TiO2pigments have silica, zinc
oxide, or alumina treatments, they can develop hydrogen bonding. Hydrogen bonding manifests itself as viscosity instability. The viscosity may increase slowly over a period of several months or it may increase rapidly in a few days or weeks. If the water content reaches two percent based on the weight of carboxyl-modified vinyl, the paint may even gel.
Commercial-grade materials typically limit water content adequately and should introduce no serious viscosity instability. If water does contaminate the formulation, it may come from the solvents or be introduced through poor storage practices.
Organic acids, mineral acids, and certain acid-esters will reverse bridging from excessive moisture. Organic acids (such as citric, maleic, or malonic) or mineral acids (such as phosphoric) are all effective at concentrations of one-fourth to one percent, based on the weight of the carboxyl-modified vinyl resin.
To restore a gelled paint to fluidity, first prepare a solution of the acid or acid-ester in acetone or other compatible solvent. Then, slowly add the solution to the gelled paint with agitation. Acid treatment of the coating may, however, affect adhesion and reduce gloss.
(a) Natural oxides are not satisfactory. Synthetic oxides are satisfactory in either air-dried or baked coatings.
Modification with Other Polymers
A small amount of acid or acid-ester can also prevent or minimize viscosity excursions during paint manufacture. As with the restoration of gelled paints, this treatment may also affect adhesion and reduce gloss.
The best way to control viscosity aberrations from water content is to prevent water from entering the formulation.
Pigments can be easily dispersed into vinyl coatings with conventional equipment, such as a pebble mill, sand grinder, and high-speed stirrers. To prevent iron contamination, do not use steel ball mills for pigment dispersion. The most common technique is to dissolve the vinyl resin in the appropriate solvents. The vinyl solution is
then blended with the plasticizers, stabilizers, grinding aid, and pigments. For higher gloss coatings, predisperse the pigment in plasticizer, thinner, and grinding aid before adding to the vinyl resin solution.
Where maximum gloss is desired, add pigments in either vinyl pigment chip or vinyl pigment paste form. For faster dispersion, incorporate wetting agents in the formulation. Soya lecithin or Nuosperse 657 (Creanova, Inc.) have been extensively tested and are effective wetting agents, when used in concentrations of one to five percent, based on pigment weight. Other suppliers such as Byk Chemie offer additives useful for pigment dispersion.
Compatibility
The vinyl chloride/vinyl acetate copolymers are compatible with each other and with most acrylic resins. They have, however, a low order of compatibility with most other resin types. UCAR™Carboxyl-Modified Solution Vinyl Resins will improve the general adhesion characteristics of other UCAR™Solution Vinyl Resins. They will also improve air-dry adhesion of many acrylic coatings. UCAR™ Hydroxyl-Modified Solution Vinyl Resins (notably VAGF, VAGC, VAGH, VAGD, VROH) are compatible with a broad range of other film formers, such as alkyds, melamines, ureas, epoxies, and urethane prepolymers. Table 9 lists typical modifiers and shows their relative compatibility with UCAR™ Hydroxyl-Modified Solution Vinyl Resins.
Reactive (Crosslinking) Systems
UCAR™Hydroxyl-Modified Solution Vinyl Resins can be cured with amino resins or isocyanate prepolymers to increase film hardness and resistance to solvents, chemicals, and moisture. Vinyl wood sealers cured with urea formaldehyde resins and acid catalysts cure rapidly at ambient temperature or short, low-temperature bake cycles. Vinyl coatings for metal containers cured with phenolic or melamine resins require higher bake
temperatures, but the resulting coatings have excellent resistance to water immersion, pasteurization, and steam sterilization.
Hydroxyl-modified resins cured with urethane prepolymers cure at ambient temperature or low bakes. Films can range from hard to elastomeric depending on the choice of urethane prepolymer.
Table 9–Compatibility
aof UCAR
™Hydroxyl-Modified Solution
Vinyl Resins with Other Resins
Vinyl/Modifier Ratiob
VAGH VAGD VROH
Modifier Resin 4:1 1:4 4:1 1:4 4:1 1:4
Alkyds (non-drying)c
Beckosol 12-021, coconut, short oil, PA content - 47% C C C C C C Alkyds (drying)c
Beckosol 11-035, soya, medium oil, PA content - 35% C I C I H I Beckosol 12-005, soya, short oil, PA content - 42% C C C C C C Beckosol 11-070,
linseed/soya, medium oil, PA content - 31% C I C I H I
Beckosol 12-054,
tall oil fatty acids, short oil, PA content - 41% C C C C C C Urea-Formaldehyde Resinsd
Beetle 55 (methylated resin) I I I I I I
Beetle 60 (methylated resin) I I I I I I
Beetle 65 (methylated resin) I I I I I I
Beetle 80 (butylated resin) C C C C C C
Hexamethoxymethylmelamined
Cymel 303 C C C C C C
Melamine-Formaldehyde Resinsd
Cymel 350 C C C C C C
Cymel 370 (methylated resin) C C C C C C
Cymel 225-10 (rapid-cure resin) H I H I H I
Urethane Prepolymerse
Mondur CB-60, aromatic polyisocyanate C C C C C C
Desmondur N-75, aliphatic polyisocyanate C C C C C C
Mondur HC, polyisocyanate copolymer C C C C C C
Key:
C = Compatible (a) 5-mil (125 microns) wet drawdowns on glass; coatings dried 20 min at 140°F (60°C) prior to rating H = Haze in film, but coating uniform (b) Solids basis
I = Incompatible (c) Supplier: Reichhold PA = Phthalic Anhydride (d) Supplier: Cytec Industries
Adhesion
Where Not to Use Vinyl Coatings
For good adhesion, surfaces must be free of rust, grease, oil, dirt, and other contamination. Common techniques for cleaning surfaces include solvent wash, vapor degreasing, chemical
treatment, and brush cleaning. For maximum adhesion, use a phosphate treatment or a vinyl butyral wash primer before applying the vinyl coating. Where vinyl butyral primers are used, the next coat must be based predominantly on hydroxyl-modified resins (VAGF, VAGC, VAGH, or VAGD).
Maximum adhesion of vinyl coatings is usually obtained at bake temperatures high enough to drive out traces of residual solvents. Over porous surfaces, such as concrete and cloth, mechanical adhesion should be sufficient for
good performance; baking is not generally needed. Baking finishes can be cured with heated air, infrared radiation, or by heating the metal surface on which the coating is applied. Control temperature carefully to avoid overbaking the coating. Maintain proper ventilation and uniform temperature distribution.
UCAR™Hydroxyl-Modified Solution Vinyl Resins adhere well to many types of finishes and are quite useful in applications where coatings based on the unmodified vinyl resins will not adhere. UCAR™Carboxyl-Modified Solution Vinyl Resins adhere to clean metal and to air-dry or baked topcoats or primers. Table 10 compares the air-dry adhesion of coatings based on the three basic types of UCAR™Solution Vinyl Resins.
Vinyl coatings should not be used in applications where the continuous service temperature exceeds 140ºF (60ºC).
No specific recommendations can be made for applications where the service temperature of the coating exceeds 140ºF (60ºC) intermittently or repeatedly.
The recommendations for the use of heat stabilizers in UCAR™Solution Vinyl Resins, given elsewhere in this booklet, are specific to a single-bake operation. The formulator is cautioned not to directly apply information about heat stabilizers to applications where service temperature exceeds 140ºF (60ºC) intermittently. Heat stabilizers that are effective at high bakes—in excess of 350ºF (176ºC)—may have an adverse effect on coating adhesion if used at lower service temperatures.
Table 10–Air-Dry Adhesion of Coatings Based on
UCAR
™Solution Vinyl Resins
Substrate VYHH VAGH VMCH
Acrylic and Methacrylic Ester Resins Excellent Excellent Excellent
Alkyd Resin Poor Excellent Fair
Cloth Poor Good Fair to Excellent
Concrete (somewhat dependent on type) Good Good Excellent
Glass Poor Fair Fair
Metal (clean and smooth) Poor Poor Excellent
Metal, Phosphatized Poor Fair Excellent
Nitrocellulose Poor Poor Fair
Oleoresinous (varies widely) Poor Fair to Excellent Poor
Paper Poor Good Good
Phenolic Resins Poor Good Fair
Plaster (somewhat dependent on type) Good Good Excellent
Rubber, Chlorinated Fair Fair Fair
Shellac Poor Good Poor
Urea Resins Poor Good Fair
Vinyl Butyral Resin Poor Excellent Fair
Vinyl Chloride Resins Excellent Excellent Excellent
Product Stewardship
The Dow Chemical Company has a fundamental concern for all who make, distribute, and use its products, and for the environment in which we live. This concern is the basis of our Product Stewardship philosophy by which we assess the health and environmental information on our products and then take appropriate steps to protect employee and public health and the environment. Our Product Stewardship program rests with every individual involved with Dow products from the initial concept and research to the manufacture, sale, distribution, and disposal of each product.
When considering the use of any Dow products in a particular application, you should review our latest Material Safety Data Sheets and ensure that the use you intend can be accomplished safely. For Material Safety Data Sheets and other product safety information, contact Dow at the numbers of the back cover of this brochure. Before handling any other products mentioned in the text, you should obtain available product safety information and take necessary steps to ensure safety of use.
NOTICE: No freedom from any patent owned by Seller or others is to be inferred. Because use conditions and applicable laws may differ from one
location to another and may change with time, Customer is responsible for determining whether products and the information in this document are appropriate for Customer’s use and for ensuring that Customer’s workplace and disposal practices are in compliance with applicable laws and other governmental enactments. Seller assumes no obligation or liability for the information in this document. NO WARRANTIES ARE GIVEN; ALL IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE ARE EXPRESSLY EXCLUDED.
Published December 2006.
The Dow Chemical Company
Midland, Michigan 48674 U.S.A.
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