Clear topcoat coatings for wood

Clear topcoats for grain printed, paper overlay and wet print interior wood paneling comprising a low Tg acrylic latex emulsion polymer, a high Tg non-film forming plastic pigment latex emulsion and a glycoluril crosslinker in a solids ratio of 1:6 parts latex to 1 part crosslinker provide coatings of excellent block resistance and gloss retention adapted to cure at temperatures of from about 100.degree. F. to 260.degree. F.

BACKGROUND OF THE INVENTION 
This invention relates to emulsion polymer based wood coatings and more 
particularly relates to a functional low Tg emulsion polymer in 
combination with a glycoluril derivative and a non-functional high Tg 
emulsion polymer to form a clear topcoat for plywood and hardboard 
interior paneling. 
Clear topcoats for interior wood paneling have some rather stringent 
performance requirements which are extremely difficult to achieve in 
waterborne systems. These performance requirements include: clarity (no 
haziness or milkiness); block resistance (approximately 1 min. after 
topcoat is applied, panels are stacked face to face for shipping, and 
there can be no sticking of coated panels which are exposed to stack 
pressures as high as 120 psi); low temperature cure (clear topcoats must 
be capable of forming a film and curing in 20-30 sec. at F.B.S.T.'s of 
165.degree.-205.degree. F.); variable gloss requirements are necessary for 
each wood species (therefore, the topcoat composition must provide some 
means for varying gloss); water resistance (the topcoat must not whiten or 
blister when exposed to high humidity or come directly in contact with 
water); tape release masking tape (e.g. Scotch brand #250 must be released 
by the substrate without damage to the finish); and stain resistance (the 
topcoat must not be damaged by several common household substances, e.g. 
detergent solutions, ammonia, solvents, lipstick, grape juice, nail polish 
remover, etc.). 
Current coating compositions for wood coatings, particularly for interior 
wood paneling, are primarily solvent based wood coatings. Latex polymers 
are desirable waterborne binder systems for wood coatings, but are 
inadequate due to various characteristics of latexes. Block resistance is 
the most severe problem since the latex polymer must be soft enough to 
provide good cohesive film properties and yet be hard enough to resist 
sticking together of adjacent panels stacked one on top of the other for 
shipping or storage purposes. Since it is difficult to adjust the Tg of a 
latex polymer to obtain the proper balance of properties, the necessary 
filming properties are generally achieved at the expense of block 
resistance, and a product with unacceptable blocking properties is 
produced. It is known that a waterborne emulsion based clear coating with 
the proper balance of filming properties and block resistance is 
obtainable if the latex polymer composition contains a functional monomer 
that promotes crosslinking with an aminoplast resin. However, it has been 
our experience that a clear coating of this nature will not have the 
proper balance of properties at lauan plywood bake conditions unless the 
latex Tg is low enough to provide good coalescence at 
165.degree.-205.degree. F., and the volume solids ratio of the 
crosslinking resin is greater than or equal to that of the latex polymer. 
Even though the aforementioned coating composition has the desired balance 
of properties, it has not gained total acceptance by the paneling 
producers because of excessive costs and formaldehyde emissions. Since 
both of these coating parameters are directly proportional to the amount 
of aminoplast resin in the formulation, it becomes obvious that good 
filming properties and block resistance must be achieved at significantly 
reduced aminoplast resin content in order to satisfy all the desires of 
the paneling producers. As far as formaldehyde emissions are concerned, 
glycoluril crosslinkers are favored over urea or melamine formaldehyde 
types since they tend to generate significantly reduced levels of 
formaldehyde during the cure cycle. 
It now has been found that highly desirable wood coatings can be produced 
based on a polymeric composition comprising a non-film forming high Tg 
emulsion polymer, sometimes referred to as plastic pigment, in combination 
with glycoluril and a low Tg emulsion polymer. The preferred composition 
comprises a reactive, low Tg polymer having reactive hydroxyl, carboxyl, 
or acrylamide groups adapted to be coreactive with glycoluril at 
relatively low temperatures in conjunction with a high Tg polymer, 
especially plastic pigment emulsions. Good cohesive film properties are 
achieved while maintaining superior block resistance comparable to 
commercial solvent based topcoats. These and other advantages of this 
invention will become more apparent by referring to the detailed 
description and illustrative examples. 
U.S. Pat. Nos. 4,265,969 and 4,301,210 teach overcoating pigment with 
plastic pigment to improve surface gloss in coated paper. 
Japanese Pat. No. JP 51/111277 (761001) teaches heat-sealing paper sheets 
by coating with a suspension of fine thermoplastic resin particles. 
Japanese Pat. No. JP 58/060091 (830409) teaches a pigment composition for 
coated paper where various pigments, including plastic pigment, is used 
with dextrose and emulsion copolymerized latex. Japanese Pat. No. 58/22974 
(830721) teaches white ink composition for jet printing containing 
water-soluble resin, plastic pigment and water-soluble solvent. Japanese 
Pat. No. 58/054096 teaches a pigment composition (including plastic 
pigment) for coated paper in combination with an emulsion polymer latex. 
Japanese Pat. No. JP 58/046198 teaches an undercoating comprising various 
pigments including plastic pigment. Japanese Pat. No. JP 57/61193 (OJI) 
teaches paper coated with high solids (pigment dispersed in latex). U.S. 
Pat. Nos. 4,277,385 (810,707) and 4,283,320 (810,811) teach crack-free 
paints using an aqueous latex dispersion paint comprising 15-25 volume 
percent (dry solids basis) film-forming acrylic latex binders, 72-77% 
solid non-cellular, non-film forming polymer particles, and 3-8% opacified 
pigment of refractive index at 1.8. The binder has an average particle 
size of 0.1-0.5 microns and a Tg of at least 5.degree. C. below the 
coalescent temperature. The polymer particles have an average size 
0.05-0.8 microns and have Tg at least 30.degree. C. above the Tg of the 
binder. None of the above patents teach how to develop block resistant 
thermoset clear coatings utilizing glycoluril crosslinking with plastic 
pigments. 
Coassigned U.S. Pat. Nos. 4,283,320; 4,277,385; and 4,069,186, which relate 
generally to opaque coatings incorporating a variety of plastic pigments, 
are incorporated herein. 
SUMMARY OF THE INVENTION 
Briefly, a low Tg film forming emulsion polymer having a Tg less than 
30.degree. C. and comprising copolymerized ethylenically unsaturated 
monomers, preferably including minor amounts of reactive hydroxyl, 
carboxyl, or acrylamide monomer is combined with a glycouril derivative 
and a high Tg (&gt;55.degree. C.) non-film forming emulsion to provide an 
aqueous coating composition adapted to be cured into a hard film by 
application of moderate heat between about 40.degree. C. and 100.degree. 
C. to provide an excellent non-blocking coating. 
The composition of this invention on a volume solids basis can contain 
between 15 and 50% glycoluril derivative and between 85 and 50% total 
emulsion latex polymer comprising a mixture of low Tg and high Tg polymer. 
The preferred composition on the same basis contains 25% glycoluril 
derivative, 75% latex mixture with 40% of the coating solids composition 
comprising a high Tg non-film forming emulsion polymer. 
One aspect of the invention relates to a process for applying a coating to 
plywood paneling which comprises an acrylic latex emulsion polymer and a 
glycoluril crosslinking agent in a volume ratio of 1-6 parts latex to 1 
part crosslinker and wherein said emulsion polymer has a Tg of from 
0.degree. C. to 30.degree. C. and is adapted to cure with said 
crosslinking agent at elevated temperatures, the improvement which 
comprises replacing at least 40% of the resin solids by volume with a 
plastic pigment latex to provide a clear block-resistant coating to said 
plywood. 
A further aspect relates to the process where a plywood substrate is coated 
according to the above process wherein the plastic pigment is a high Tg 
non-film forming aqueous latex emulsion of substantially polystyrene. 
DETAILED DESCRIPTION OF THE INVENTION 
This invention relates to improved aqueous latex emulsion coatings useful 
for clear topcoats for interior wood paneling and to a process for coating 
plywood panels such as grain printed, paper overlay or wet print panels. 
The improved coatings comprise 1-6 parts aqueous emulsion polymer per part 
of a crosslinking agent, preferably glycoluril crosslinkers, adapted to 
cure with emulsion polymer; the emulsion polymer consists of (1) an 
aqueous latex emulsion polymer having a Tg of less than 30.degree. C. and 
preferably from about 20.degree. C. to about 30.degree. C. and having 
reactive functionality adapted to cure with the glycoluril crosslinking 
agent; and (2) a plastic pigment latex comprising at least 40 volume 
percent of the total resin solids. 
Referring first to the latex emulsion (1) having a Tg of less than about 
30.degree. C., these polymers comprise copolymerized ethylenically 
unsaturated monomers and can include vinyl unsaturated monomers containing 
vinyl double bond unsaturation including, for example, vinyl esters such 
as vinyl acetate, vinyl proprionate, vinyl butyrates, vinyl benzoate, 
isopropenyl acetate and like vinyl esters; vinyl amides, such as 
acrylamide, and methacrylamide; and vinyl halides such as vinyl chloride. 
Ethylenically unsaturated monomers other than vinyl unsaturated monomers 
can include, for example, styrene, methyl styrenes and similar alkyl 
styrenes, chlorostyrene, vinyl voluene, vinyl naphthalene, divinyl 
benzene, diallyl phthalate, and similar diallyl derivatives, butadiene, 
alkyl esters of acrylic and methacrylic acid and similar ethylenically 
unsaturated monomers. Acrylic unsaturated monomers include lower alkyl 
esters of acrylic or methacrylic acid having an alkyl ester portion 
containing between 1 to 12 carbon atoms as well as aromatic derivatives of 
acrylic and methacrylic acid, and can include, for example, acrylic and 
methacrylic acid, methyl acrylate and methacrylate, ethyl acrylate and 
methacrylate, butyl acrylate and methacrylate, propyl acrylate and 
methacrylate, 2-ethyl hexyl acrylate and methacrylate, cyclohexyl acrylate 
and methacrylate, decyl acrylate and methacrylate, isodecylacrylate and 
methacrylate, benzyl acrylate and methacrylate and various reaction 
products such as butyl, phenyl, and cresyl glycidyl ethers reacted with 
acrylic and methacrylic acids. Preferred polymers include reactive 
copolymerized monomers such as reactive monomers of acrylamide, carboxyl 
monomer, or hydroxyl monomer whereby the reactive groups are adapted to be 
coreactive and crosslinked with glycoluril. Preferable the polymers 
contain polymerized monomer by weight between 1% and 20% hydroxyl monomer, 
with the balance being other ethylenic monomers. The acrylamide monomers 
can be acrylamide, methacrylamide, ethylacrylamide, acrylonitrile, 
methacrylonitrile, and similar atoms alkyl acrylamide and methacrylamide 
monomers; N-alkanol amide monomers including for example, N-methylol 
acrylamide, N-ethanol acrylamide, N-propanol acrylamide, N-methylol 
methacrylamide, N-ethanol methacrylamide, and similar acrylamides and 
methacrylamide. Carboxyl containing monomers are ethylenically unsaturated 
monomers containing carboxyl group such as acrylic, methacrylic or 
ethacrylic acid, as well as itaconic, citriconic, fumaric, maleic, 
measonic and aconitic acids. The preferred acids are acrylic and 
methacrylic acids. Hydroxyl containing monomers ethylenically unsaturated 
monomers containing a hydroxyl and can include for example, hydroxy alkyl 
acrylates or methacrylates such as hydroxyethyl, hydroxypropyl, 
hydroxybutyl, hydroxyhexyl, hydroxyoctyl, and similar lower alkyl hydroxyl 
acrylates and methacrylates. The ethylenically unsaturated monomers can be 
copolymerized by free radical induced addition polymerization using peroxy 
or azo catalysts, common redoc catalysts, ultraviolet radiation, or the 
like. 
Referring now more specifically to the differences between the high Tg 
polymer and the low Tg polymer, the glass transition temperature (Tg) for 
the high Tg polymer should be above about 55.degree. C. and the low Tg 
polymer should have a Tg less than 30.degree. C. Hard monomers imparting a 
higher Tg include styrene, methyl-methacrylate and substituted styrenes 
whereas soft monomers include lower alkyl acrylates such as methyl, ethyl, 
propyl, and butyl acrylates. The term "glass transition temperature" is a 
term well known in the art and generally defines the onset of long-range 
molecular motion wherein the polymer preserves the outward appearance of a 
solid but becomes rubbery and then tacky with increasing temperature and 
undergoes plastic flow and elastic deformation. A polymer particle having 
a glass transition temperature greater than room temperature will be a 
non-film former at room temperature. The glass transition temperature can 
be measured in accordance with 41 Journal of Paint Technology, pages 
167-169 (1969). The Tg can be calculated with the Fox equation (Fox 
equation is 1/Tg=EW.sub.i Ti) are estimated by testing for a Vicat 
softening point as set forth in ASTM 1525. Both the high Tg and low Tg 
polymer particles have a weighted average particle diameter between about 
1,000 .ANG. and 10,000 .ANG. (0.1 to 1.0 microns). 
In accordance with this invention, the high Tg non-film forming emulsion 
polymer particles are linear polymers produced by copolymerizing 
monoethylenically unsaturated monomers with minor amounts of difunctional 
or multifunctional monomers. Divinyl benzene, for example, has an 
ethylenic unsaturation functionality of two and a crosslinking site of one 
since the other double bond is considered copolymerized in the polymer 
chain. For definition purposes, the crosslink density of the polymer is 
the number of equivalent crosslinking sites in a gram mole of 
multifunctional monomer per kilogram of polymer. A polymer containing 10 
grams of divinyl benzene copolymerized with 990 grams of monofunctional 
monomer (styrene), for example, has 10/130 crosslinking sites or a 
crosslinking density of 0.0769 equivalent crosslinking sites per kilogram 
of polymer. On a weight percentage basis, the polymer particles generally 
contain between 0.1% to 10% crosslinking or difunctional monomer. Suitable 
difunctional crosslinking vinyl monomers include, for example, diallyl 
phthalate, divinyl benzene, divinyl ether, neopentyl glycol diacrylate, 
diallyl phenyl phosphonate, diallyl isopropylidene, and 1.6 hexane 
diacrylate and similar diacrylates as well as other difunctional vinyl 
monomers having reactive difunctional ethylenic unsaturation capable of 
crosslinking other ethylenically unsaturated vinyl monomers. Other high Tg 
polymers may be used including latex polymers prepared by methods other 
than emulsion polymerization. 
Preferred high Tg non-film forming emulsion polymers are sometimes referred 
to as "plastic pigments". The non-film forming particles are preferably 
polystyrene, but can be polymers and copolymers of other ethylenically 
unsaturated monomers such as disclosed in U.S. Pat. No. 3,423,351 provided 
the Tg of the particles are sufficient and do not coalesce at the ambient 
application and mild curing temperatures. The non-film forming polymer 
particles can be copolymerized ethylenically unsaturated monomers having a 
carbon-to-carbon ethylenic double bond unsaturation capable of addition 
polymerization through the ethylenic double bond and can include, for 
example, styrene, substituted styrenes, vinyl chloride, vinylidene 
chloride, acrylonitrile, methacrylonitrile, esters of acrylic and 
methacrylic acid and tertiary butyl acrylate wherein the polymers or 
copolymers thereof having a Tg greater than about 30.degree. C. Preferred 
polymer particles are polystyrene, polyvinyl chloride, and polymethyl 
methacrylate, as further illustrated in the examples. 
Plastic pigment particles are further disclosed in U.S. Pat. No. 4,069,186; 
U.S. Pat. No. 4,277,385; and U.S. Pat. No. 4,283,320 which, together with 
U.S. Pat. No. 3,423,351, are incorporated herein by reference. 
Especially preferred are styrene emulsion polymers containing a minor 
amount of methacrylic acid as disclosed in U.S. Pat. No. 4,283,320. Other 
useful non-film forming high Tg emulsion latex polymer can contain 
copolymerized monomers and optionally very minor amounts of acrylamide, 
methacrylamide, N-methylol acrylamide, hydroxyalkyl monomer and major 
amounts of other ethylenically unsaturated non-film forming monomers. 
The coating composition of this invention for application to wood and 
plywood paneling comprises on a solids volume basis: 
(A) 1 to 6 parts by volume (solids) of an aqueous emulsion consisting of a 
mixture of 
(1) a film forming aqueous acrylic polymer latex having a Tg of less than 
30.degree. C. and preferably from about 20.degree. C. to about 30.degree. 
C. adapted to cure with a glycoluril crosslinking agent under baking 
conditions of from about 100.degree. C. to 260.degree. C.; and 
(2) a non-film forming plastic pigment emulsion latex present in the 
mixture in an amount at least 40 volume percent resin solids basis and 
derived by the aqueous emulsion polymerization of ethylenically 
unsaturated monomer optionally containing up to 2 weight percent (basis 
monomer solids) of copolymerized acid monomer selected from acrylic or 
methacrylic acid. 
(B) 1 part glycoluril crosslinking agent. 
A preferred composition contains between 90 and 315 weight parts of 
glycoluril derivative, between 299 and 361 weight parts of the latex 
mixture, comprising from about 160 to about 170 weight parts of the high 
Tg non-film forming emulsion polymer. 
In practice, the high Tg emulsion polymer and the low Tg emulsion polymer 
are synthesized separately although by similar processes but using 
different combinations of monomers to obtain the proper Tg polymer 
particle. In either process, the ethylenic monomers can be polymerized in 
an aqueous medium at a pH preferably between about 1.0 and 6. Generally, 
the polymerization is conducted at a temperature of about 
20.degree.-100.degree. C. in the presence of a free radical generating 
catalyst. Commonly used free radical initiators include various peroxygen 
compounds such as the persulfates, benzoyl peroxide, t-butyl 
hydroperoxide, cumene hydroperoxide, t-butyl diperphthalate, pelargonyl 
peroxide and 1-hydroxycyclohexyl hydroperoxide; azo compounds such as 
azodiisobutyronitrile and dimethylazodiisobutyrate; and the like. 
Particularly preferred as polymerization initiators are the water-soluble 
peroxygen compounds such as hydrogen peroxide and the sodium, potassium 
and ammonium persulfates used by themselves or in activated "redox" type 
systems. Typical "redox" systems include alkali metal persulfates with: A 
reducing substance such as a polyhydroxy phenol and oxidizable sulfur 
compound such as sodium sulfite or sodium bisulfite, a reducing sugar, 
dimethylamino propionitrile, a diazomercapto compound and a ferricyanide 
compound, and the like. The amount of initiator used will generally be in 
the range between about 0.1 to 3% by weight based on the monomers and 
preferably is maintained between 0.15 and 0.8% by weight. Usually the 
initiator will all be charged at the outset of the polymerization; 
however, incremental addition or proportioning of the initiator is often 
employed. 
When an emulsifier is used to prepare the latices of this invention, they 
are the general types of anionic and non-ionic emulsifiers. Exemplary 
anionic emulsifiers which may be employed are: alkali metal or ammonium 
salts of the sulfates of alcohols having from 8 to 18 carbon atoms, such 
as sodium lauryl sulfate, ethanolamine lauryl sulfate, ethylamide lauryl 
sulfate; alkali metal and ammonium salts of sulfonated petroleum or 
paraffin oils; sodium salts of aromatic sulfonic acids, such as 
dodecane-1-sulfonic acid and octadiene-1-sulfonic acid; aralkylsulfonates 
such as sodium isopropyl benzene sulfonate, sodium dodecyl benzene 
sulfonate, and sodium isobutyl naphthalene sulfonate; alkali metal and 
ammonium salts of sulfonated dicarboxylic acid esters such as sodium 
dioctyl sulfosuccinate, disodium N-octadecylsulfosuccinamate; alkali metal 
or ammonium salts of free acids of complex organic mono- and diphosphate 
esters and the like. So-called non-ionic emulsifiers such as octyl- or 
nonylphenyl polyethoxyethanol and the like may also be used. The amount of 
emulsifier used may be from about 0.01 to 6% or more by weight of the 
monomers. All the emulsifiers may be added at the beginning of the 
polymerization or it may be added incrementally or by proportioning 
throughout the run. Typical polymerizations for the preparation of the 
high Tg emulsion polymers or low Tg emulsion polymers of this invention 
are conducted by charging the monomers into the polymerization reactor 
which contains water and a portion of the emulsifying agent. The reactor 
and its contents are heated and the initiator added. 
Thermosetting compositions can be produced where high Tg and low Tg 
emulsion polymers contain reactive hydroxyl, carboxyl, or acrylamide 
groups adapted to be crosslinked by reaction with a glycoluril derivative. 
Glycoluril derivatives are disclosed in U.S. Pat. No. 4,604,191 and are 
also known as acetylendiureas. Glycolurils are derived by reacting two 
moles of urea with one mole of glyoxal to provide a complex ring structure 
illustrated as follows: 
##STR1## 
The substitute constituents can be a hydrogen, or a lower alkyl radical, 
or can be methylolated partially or fully by reacting 1 to 4 moles of 
formaldehyde to provide a methylol glycoluril. The preparation of various 
glycolurils are illustrated in U.S. Pat. No. 4,064,191 such as 
tetramethylol glycoluril, tetrabutoxymethyl glycoluril, partially 
methyolated glycoluril, tetramethyoxymethyl glycoluril, and 
dimethoxydiethoxy glycoluril. Useful glycoluril derivatives include for 
example, mono- and dimethylether or dimethylol glycoluril, the 
trimethylether of tetramethylol glycoluril, the tetramethylether of 
tetramethylol glycoluril, tetrakisethoxymethyl glycoluril, 
tetrakisopropoxmethyl glycoluril, tetrakisbutoxymethyl glycoluril, 
tetrakisamyloxymethyl glycoluril, tetrakishexoxymethyl glycoluril and the 
like. Further glycoluril derivatives include dimethylol dihydroxy ethylene 
urea which is believed to have the following chemical structure: 
##STR2## 
This invention contemplates the use of various crosslinking compositions 
that effect cure by reaction with the functional group moieties of the low 
Tg latex. Such crosslinkers include the aminoplast, melamine, urea 
formaldehyde and glycoluril cure catalysts. The glycoluril cure catalysts 
are especially preferred such as Cymel 1172 and Cymel 1175 exemplified in 
coassigned U.S. Pat. No. 4,444,941 and U.S. Pat. No. 4,442,257 
incorporated herein by reference. 
Thermosetting compositions of this invention comprise on a polymer volume 
basis at least about 40% high Tg emulsion polymer with the remaining 
reactive low Tg film forming latex and glycoluril derivatives. Minor 
amounts of other latex or water dispersed polymer can be added if desired. 
The thermosetting compositions cure quickly at low temperatures under 
acidic curing conditions. Acid catalysts, such as p-toluene sulfonic acid 
(3 to 5 percent by weight crosslinker solids), are useful for accelerating 
the cure. The thermosetting composition can be used as a clear coating or 
as a pigmented coating.

The merits of this invention are further illustrated in the following 
examples. These examples should not be read in a restrictive manner. 
Unless otherwise indicated, temperatures are given in degrees Fahrenheit 
and percentages are expressed as weight percentages. 
EXAMPLE 1 
(a) Latex 
An emulsion polymer was produced from the following components: 
______________________________________ 
Grams 
______________________________________ 
deionized water 85.6 
sodium dihexyl sulfosuccinate 
0.5 
potassium carbonate 0.136 
ammonium persulfate 0.273 
sodium bis-tridecyl suffosuccinate 
0.319 
butyl acrylate 39.0 
methyl methacrylate 39.0 
N--isobutoxymethyl acrylamide 
12.0 
2-hydroxyethyl acrylate 
6.0 
glacial methacrylic acid 
4.0 
sodium formaldehyde sulfoxylate 
0.180 
tertiary butyl hydroperoxide 
0.012 
______________________________________ 
The emulsion polymer is prepared as follows. The monomers are polymerized 
in a conventional reactor using a standard procedure of metering in the 
main body of monomer into the heated water plus surfactant and potassium 
carbonate over a 2- to 5-hour interval. Batch loading of monomer is 
possible, but not preferred. Changing the monomer composition during the 
feed is also possible and may lead to faster cure and/or cleaner batches. 
The reactor is run at 60.degree.-86.degree. C. The sodium formaldehyde 
sulfoxylate and t-butyl hydroperoxide are added after the main body of 
monomers have been polymerized in order that traces of free monomers are 
reacted. 
The film forming emulsion polymer latex is particularly suitable as a 
binder system for a paint composition. The latex polymer has a Tg of 
20.degree. C. 
(b) Plastic Pigment (High Tg) 
Plastic pigment latex emulsion was prepared generally as set forth in U.S. 
Pat. No. 4,069,186 and other patents noted above. The non-film forming 
polymer particles have a weighted average particle diameter between 0.1 
and 1.0 microns, advantageously between 1,000 .ANG. to 8,000 .ANG. and 
preferably between 1,000 .ANG. to 6,000 .ANG.. 
(c) Paint Composition 
The foregoing latex (a) can be utilized to produce a useful paint 
composition which can be applied to a substrate and cured at low 
temperatures such as 10 minutes at 120.degree. F., or an oven bake and/or 
infrared heat to achieve a substrate surface temperature of from about 
100.degree. F. to about 260.degree. F. A typical paint composition is as 
follows: 
EXAMPLE 2 
A clear topcoat coating was prepared by combining the following ingredients 
in the proportion indicated. 
______________________________________ 
Lbs. Gal. 
______________________________________ 
Latex (a) (20.degree. C. Tg) 
289.4 32.26 
Non-Ionic Surfactant 
3.0 .36 
T.M.G.U. (75% N.V.)* 
210.26 18.11 
Latex (b) (100.degree. C. Tg) 
354.60 41.33 
Organosilicone Slip-aid 
9.0 1.02 
Carnuba Wax Emulsion 
25.0 3.00 
Silicone Slip-aid 3.0 .37 
Defoamer 3.0 .40 
Hydroxy Methyl Cellulose 
26.24 3.15 
10% solution ** ** 
______________________________________ 
*(Tetramethylol glycoluril) 
**Total Lbs. 923.50 Total Gal. 100.00 
The performance characteristics of the topcoat were observed over Champion 
paper overlay lauan plywood substrate. The following results were 
recorded: 
______________________________________ 
#250 Masking Tape Release 
100% Release 
60.degree. Gloss 28.9% 
MEK Resistance (double rubs) 
16 
Block Resistance @ 65.degree. C.-120 PSI 
No sticking 
______________________________________ 
EXAMPLES 3-10 
Topcoats were prepared essentially as indicated in Example 2 with the 
exception that the ingredients were varied as follows: 
______________________________________ 
Latex Latex Glyco- 60.degree. Block 
(a) (b) luril* Gloss Resis- 
Example 
(%) (%) (%) (%) Clarity 
tance 
______________________________________ 
3 54 0 46 44.0 Clear Poor 
4 48.57 10 41.43 40.0 Clear Poor 
5 43.14 20 36.86 35.8 Clear Fair 
6 37.71 30 32.29 26.3 Clear Fair-Good 
7 32.28 40 27.72 18.6 Clear Excellent 
8 26.85 50 23.15 18.7 Sl. Excellent 
Haze 
9 21.42 60 18.58 12.3 Cloudy 
Excellent 
10 16 70 14 16.8 Opaque 
Excellent 
______________________________________ 
*Tetramethylol glycoluril 
As seen in the above table a clear film with excellent block resistance is 
obtained when 40% of the total polymer solids by volume is non-film 
forming latex emulsion polymer. 
The foregoing description and illustrative examples demonstrate the merits 
of an excellent wood coating comprising high Tg reactive emulsion polymer 
and coreactive glycoluril, but are not intended to be limiting except by 
the appended claims.