High solids coatings from new tetrahydroxy oligomers

A novel tetrahydroxy oligomer crosslinkable with amine-aldehyde resins to form a coating composition adapted for use as an automotive topcoat and which upon curing forms a hard, glossy, coating with outstanding durability and excellent resistance to solvents and water. The coating composition comprises: PA1 (A) a tetrahydroxy oligomer having a number average (Mn) molecular weight of between about 600-2000 and being the reaction product of: PA2 (i) an ester containing pendant hydroxyl and carboxyl functionality and being made by a reaction wherein the reactants consist essentially of: PA3 (a) a C.sub.3 -C.sub.10 aliphatic diol, and PA3 (b) an alkyl hexahydrophthalic anhydride, wherein (a) and (b) are combined in the reaction mixture in an amount sufficient to allow reaction in about a 1:1 molar ratio; and PA2 (ii) a diepoxide having a number average molecular weight between about 130-1500, wherein (i) and (ii) are combined in the reaction mixture in an amount sufficient to allow reaction in about a 2:1 molar ratio, PA1 (B) an amine-aldehyde crosslinking agent; PA1 (C) optionally a hydroxy functional additive; and PA1 (D) solvent. The amine aldehyde crosslinking agent is included in the composition in an amount sufficient to provide at least about 0.60 equivalents of nitrogen crosslinking functionality for each equivalent of hydroxyl functionality included in the composition either on the tetrahydroxy oligomer or as a hydroxyl group of the hydroxy functional additive.

Reference is made to commonly assigned and concurrently filed U.S. 
application Ser. Nos. 334,685 entitled "New polyhydroxy Oligomers for High 
Solids Coatings I", Ser. No. 334,801 entitled "New Polyhydroxy Oligomers 
for High Solids Coatings II", Ser. No. 334,686 entitled "New High Solids 
Urethane Coatings I", Ser. No. 334,802 entitled "New High Solids Urethane 
Coatings II", Ser. No. 334,799 entitled "High Solids Urethane Coatings 
from New Tetrahydroxy Oligomers", all to Chattha. 
This invention relates to novel coating compositions. More particularly, 
the invention relates to high solids thermosetting coating compositions 
which are adapted to provide an automotive topcoat demonstrating hardness, 
high gloss, outstanding durability and excellent resistance to solvents 
and water, and which comprises novel tetrahydroxy oligomers crosslinkable 
with amine-aldehyde resins. Most particularly, this invention relates to 
high solid compositions wherein the novel tetrahydroxy oligomers are made 
by first reacting a low molecular weight branched diol with an alkyl 
hexadhydrophthalic anhydride to form a hydroxy acid ester which is 
subsequently reacted with a low molecular weight diepoxide. 
BACKGROUND OF THE INVENTION 
Because of increasingly strict solvent emissions regulations in recent 
years, low solvent emission paints have become very desirable. A number of 
high solids paint compositions have been proposed to meet these low 
solvent emission requirements. However, many of these compositions are 
deficient because of difficulty in application, slow curing rates, lack of 
flexibility, poor durability and low solvent and water resistance. 
The coating compositions of this invention combine the above discussed 
desired properties and low application viscosity so as to overcome 
deficiencies of previously proposed high solids materials. In particular, 
these low viscosity high solids coating compositions exhibit weathering 
properties superior to other single component high solids paints making 
them ideally suitable for automotive topcoats, clear or pigmented, 
including metallic flake. 
BRIEF DESCRIPTION OF THE INVENTION 
The thermosetting coating composition of this invention preferably contains 
greater than about 60% by weight, more preferably greater than 70% by 
weight, of nonvolatile solids, and exhibits superior weathering to other 
high solids single component paints. The composition comprises: 
(A) a tetrahydroxy oligomer having a number average (M.sub.n) molecular 
weight of between about 600-2000 and being the reaction product of: 
(i) an ester containing pendant hydroxyl and carboxyl functionality and 
being made by reacting: 
(a) a C.sub.3 -C.sub.10 aliphatic branched diol and 
(b) an alkyl hexadhydrophthalic anhydride, wherein (a) and (b) are combined 
in the reaction mixture in an amount sufficient to allow reaction in about 
a 1:1 molar ratio; and 
(ii) a diepoxide having a number average molecular weight between about 
130-1500, 
wherein (i) and (ii) are combined in the reaction mixture in an amount 
sufficient to allow reaction in about a 2:1 molar ratio; 
(B) an amine-aldehyde crosslinking agent; 
(C) 0-50 weight percent based on the total weight of (A), (B), (C), and (D) 
of a hydroxy functional additive having a number average molecular weight 
(M.sub.n) of between about 300-5000, preferably between about 500-2500; 
and 
(D) solvent. 
The amine-aldehyde crosslinking agent is included in the composition in an 
amount sufficient to provide at least about 0.60, preferably between about 
0.75 and 3.75, equivalents of nitrogen crosslinking functionality per 
equivalent of hydroxyl functionality included in the composition either on 
the tetrahydroxy oligomer or as a hydroxyl group of the hydroxy functional 
additive. The oligomers of this composition are compatible, in particular, 
with low molecular weight hydroxy functional acrylics. In addition, the 
high solids coating composition of this invention may include additives 
such as catalysts, antioxidants, U.V. absorbers, flow control or wetting 
agents, antistatic agents, pigments, plasticizers, etc. The oligomers of 
this composition are also compatible with nonaqueous dispersions (NAD's), 
which are generally used as flow control additives. 
The invention is also directed to the oligomer of the coating composition 
taught above. 
DETAILED DESCRIPTION OF THE INVENTION 
The coating composition of this invention provide a system which is 
particularly suitable for those applications requiring a coating having 
high gloss, hardness, durability and high solvent and water resistance as 
well as low temperature cure. The desirable characteristics of the coating 
composition of this invention, in particular the excellent physical 
properties and weatheribility, are believed to result from the steric 
hinderance to hydrolysis afforded the ester groups of the oligomer by the 
alkyl group of the anhydride. However, while this theory has been 
advanced, to explain the excellent durability of this coating composition, 
neither its validity nor its understanding is necessary for the practice 
of the invention. 
Each of the components of the coating composition, the amounts of each of 
the components required to achieve the desired results of the invention 
and a method for applying the composition are described hereinafter in 
greater detail. 
Tetrahydroxy Oligomer 
A principal material in the coating composition of this invention is a 
novel tetrahydroxy oligomer having a number average molecular weight 
(M.sub.n) between about 600 and about 2000, more preferably between about 
700 and about 1500. The oligomer is prepared by first combining a low 
molecular weight C.sub.3 -C.sub.10 aliphatic branched diol with an alkyl 
hexadhydrophthaic anhydride in the reaction mixture in an amount 
sufficient to allow reaction in about a 1:1 molar ratio to form an ester 
having pendant hydroxyl and pendant carboxyl functionality. A slight 
excess of anhydride than needed for this reaction may be used. This ester 
is subsequently reacted with a diepoxide; the ester and the diepoxide 
being combined in the reaction mixture in an amount sufficient to allow 
reaction in about a 2:1 molar ratio, forming the oligomer. By means of 
this reaction, the carboxyl of the ester opens the epoxide groups of the 
diepoxide generating two more hydroxyl functionalities. 
The aliphatic branched diol preferably contains only one primary hydroxyl 
group, the second hydroxyl of the diol is therefore preferable a secondary 
or tertiary hydroxyl, more preferably a secondary hydroxyl. Additionally 
it is preferable that the hydroxyl groups not be on adjacent carbons and 
more preferably be separated by at least three carbon atoms. The carbon 
chain may also be interrupted or substituted by non-interfering 
functionality. Suitable C.sub.3 -C.sub.10 aliphatic branched diols include 
but are not limited to, 2-ethyl-1,3-hexane diol, 1,3-butanediol and 
1,2-butane-diol with 2-ethyl-1,3-hexanediol being most preferred. Other 
suitable diols will be apparent to one skilled in the art. Mixtures of 
suitable diols can also be used. 
The alkyl hexahydrophthalic anhydride preferably contains a lower alkyl 
group, i.e., an alkyl group having about up to seven carbons, more 
preferably, up to about four carbons. Additionally, the alkyl group may be 
substituted by non-interfering functionality. Suitable anhydrides useful 
in this invention include methyl hexahydrophthalic anhydride, and its 
ethyl and propyl analogs, with methyl hexahydrophthalic anhydride being 
most preferred. 
The diepoxide suitable for use in this invention is a low molecular weight 
epoxy containing two epoxide groups per molecule and has a number average 
molecular weight of between about 130-1500. This diepoxide can be a liquid 
or a solid and can be either a single diepoxide or a mixture of suitable 
diepoxides. Examples of suitable diepoxides include but are not limited to 
condensation products of bisphenol-A with epichlorohydrin, examples of 
which are commercially available as Epon 828, 1001, 1004, 1007 and 1009 
(marketed by Shell Oil Company), Araldite 6010 and 8001 (marketed by 
Ciba-Geigy); ester-type diepoxides such as diglycidyl phthalate, 
diglycidyl adipate, and diglycidyl glutarate; cycloaliphatic diepoxides 
such as cyclopentanediene and vinyl cyclohexane dioxide; and aliphatic 
ether type diepoxides such as ethylene glycol diglycidyl ether, 
1,2-propylene glycol diglycidyl ether and 1,4 butanediol diglycidyl ether 
(Araldite RD-2 marketed by Ciba-Geigy). 
In preparing the tetrahydroxy oligomer, the diol and anhydride are 
combined, generally by adding the anhydride dropwise to the heated diol, 
and then reacted at an elevated temperature for a time necessary to 
complete the esterification reaction. Subsequently, the diepoxide is 
reacted with the ester composition, generally in the presence of a 
catalyst, and the composition is maintained at elevated temperatures until 
the reaction between the hydroxy acid ester and diepoxide is complete. 
Preferred carboxyl/epoxide catalysts useful in preparation of hydroxy 
functional oligomer are the tetralkyl ammonium salts such as tetra methyl 
ammonium chloride, tetraethyl ammonium bromide and trimethyl benzyl 
ammonium chloride as well as metal salts of a carboxylic acid, such as 
potassium octoate or chromium III octoate. Other useful catalysts include: 
metal halides such as chromium trichloride, ferric trichloride, and 
aluminum trichloride; mercaptans and thioethers such as octyl mercaptan, 
dimercapto propanol and dimercapto-diethyl ether; tertiary amines such as 
triethyl amine, pyridine, dimethylaniline, quinoline, .beta.-picoline, 
ethylpyridine; and the like. Still another catalyst known to catalyze 
carboxy/epoxy reactions will be apparent to those skilled in this art. 
Various mixtures of these types of oligomers may also be employed within 
the scope of the compositions of the invention described herein. 
Although the above reactions may be carried out with or without solvent, it 
is generally suitable and preferable in order to achieve the preferred 
high solids concentration of the coating composition to use little or no 
solvent. However, when desirable, suitable solvents which may be employed 
include those commonly used, such as toluene, xylene, methyl amyl ketone 
etc. It is however necessary to incorporate solvent into the coating 
composition in order to facilitate application of the coating composition. 
Typically solvents useful in the coating composition to facilitate 
application, for example spray application at high solids content, include 
those commonly employed, such as toluene, xylene, methyl amyl ketone, 
acetone, dioxane, butanone, 2-butoxyl-1-ethanol, diacetone alcohol, 
tetrahydrofuran, butyl acetate, cellosolve acetate, dimethyl succinate, 
dimethyl glutarate, dimethyl adipate or mixtures thereof. The solvent in 
which the tetrahydroxy functional oligomer of the coating composition may 
be prepared, may be employed as the solvent for the coating composition 
thus eliminating the need for drying the oligomer after preparation, if 
such is desired. As mentioned above, the nonvolatile solids content of the 
high solids coating composition is preferably at least 60% and more 
preferably 70% or more, thus limiting the amount of solvent included in 
the composition. However, while the tetrahydroxy oligomer of the subject 
composition are particularly suitable for making high solids coatings, 
they are also suitable in compositions that are not high solids 
compositions. Determination of optimal solids content (with the 
corresponding solvent content) for a given application would be within the 
skill of one in the art. 
Amino Crosslinking Agent 
A second essential component of the paint compositions of this invention is 
an amine-aldehyde crosslinking agent. Amine-aldehyde crosslinking agents 
suitable for crosslinking hydroxy functional bearing materials are well 
known in the art. Typically, these crosslinking materials are products of 
reactions of melamine, or urea with formaldehyde and various alcohols 
containing up to and including 4 carbon atoms. Preferably, the 
amine-aldehyde crosslinking agents useful in this invention are 
amine-aldehyde resins such as condensation products of formaldehyde with 
melamine, substituted melamine, urea, benzoguanamine or substituted 
benzoguanamine. Preferred members of this class are methylated 
melamine-formaladehyde resins such as hexamethoxymethylmelamine. These 
liquid crosslinking agents have substantially 100 percent nonvolatile 
content as measured by the foil method at 45.degree. C. for 45 minutes. 
For the purposes of the preferred high solids coatings of the invention it 
should be recognized that it is important not to introduce extraneous 
diluents that would lower the final solids content of the coating. Other 
suitable amine-aldehyde crosslinking agents would be apparent to one 
skilled in the art. 
Particularly preferred crosslinking agents are the amino crosslinking 
agents sold by American Cyanamid under the trademark "Cymel." In 
particular, Cymel 301, Cymel 303, Cymel 325 and Cymel 1156, which are 
alkylated melamine-formaldehyde resins are useful in the compositions of 
this invention. 
The crosslinking reactions are generally catalytically accelerated by 
acids. One such catalyst, for example, which may be so employed is 
p-toluene sulfonic acid, generally added to the composition in about 0.5% 
by weight based on the total weight of ester and crosslinking agent. 
The amine-aldehyde materials function as a crosslinking agent in the 
composition of the invention by reacting with the hydroxyl functionality 
of the tetrahydroxy oligomer and by reaction with the hydroxyl 
functionality on the hydroxy functional additive if such material is 
included in the composition. 
In order to achieve the outstanding properties which make these coating 
compositions particularly useful an automotive topcoat materials, it is 
essential that the amount of amino crosslinking agent be sufficient to 
substantially completely crosslink the hydroxy functionality in the 
coating composition. Therefore, the amino crosslinking agent should be 
included in the composition in an amount sufficient to provide at least 
about 0.60 equivalents, preferably between about 0.75 and about 3.75 
equivalents, of nitrogen crosslinking functionality for each equivalent of 
hydroxyl functionality included in the composition either as a hydroxyl 
group on the optional hydroxy functional additive or on the tetrahydroxy 
oligomer. 
Optional Hydroxy Functional Additive 
Additional hydroxy functionality other than that present on the 
tetrahydroxy oligomer may be achieved by adding a hydroxy functional 
additive in amounts up to about 50 weight percent based on the total of 
the three above discussed components and the hydroxy functional additive 
itself. Such a material serves to provide additional hydroxy functional 
additives so as to provide a more intimate crosslinked structure in the 
final cured product. The hydroxy functional additives useful in the 
composition are preferably selected from various polyols having a number 
average molecular weight (M.sub.n) of between about 150 and about 6000, 
preferably between about 400 and about 2500. As used herein the term 
polyol means a compound having two or more hydroxyl groups. 
The polyols useful in the invention preferably are selected from the group 
consisting of: (i) hydroxy functional polyesters; (ii) hydroxy functional 
polyethers; (iii) hydroxy functional oligoesters, (iv) monomeric polyols; 
(v) hydroxy functional copolymers produced by free radical polymerization 
of monoethylenically unsaturated monomers, one of which bears hydroxy 
functionality and which is included in the copolymer in an amount ranging 
from about 10 to about 50 weight percent, and (vi) mixtures of (i)-(v). 
U.S. Pat. No. 4,181,784 to Chattha et al teaches a high solids paint 
composition comprising an optional hydroxy functional additive. This 
patent is hereby expressly incorporated by reference as detailing hydroxy 
functional additives which are suitable for use as such in the composition 
of this invention. The following presents a brief description of the 
optional hydroxy functional additives. 
The hydroxy functional polyesters useful in the invention are preferably 
fully saturated products prepared from aliphatic dibasic acids containing 
2-20 carbon atoms, and short chain glycols of up to and including 21 
carbon atoms. The molecular weight of these materials ranges from about 
200 to about 2500 and the hydroxyl number ranges from about 30 to about 
230. 
Among preferred polyesters are products derived from esterification of 
ethylene glycol and 1,4 butane diol with adipic acid, ethylene glycol and 
1,2 propylene glycol with adipic acid, azelaic acid and sebacic acid 
copolyester diols and mixtures thereof. 
Among useful polyether diols are polytetramethylene ether glycol, 
polyethylene glycol, polypropylene glycol and the like. 
The hydroxy functional oligoesters useful as hydroxy functional additives 
in the compositions of the invention are oligoesters preferably having a 
molecular weight of between about 150 and about 300. Such oligoesters may 
be selected from the group consisting of: (i) oligoesters prepared by 
reacting a dicarboxylic acid with a monoepoxide such as an alkylene oxide; 
(ii) oligoesters prepared by reacting a polyepoxide with a monocarboxylic 
acid; and (iii) oligoesters prepared by reacting a hydroxy functional 
monocarboxylic acid with either a mono- or polyepoxide. 
Oligoester (i) prepared by reacting a dibasic carboxylic acid with a 
monoepoxide, preferably include those formed by reacting C.sub.6 -C.sub.12 
dicarboxylic aliphatic acids with ethylene oxide or propylene oxide. 
The preparation of oligoesters from carboxylic acids and polyepoxides is 
well known and is described, for example, in U.S. Pat. Nos. 2,456,408 and 
2,653,141. Numerous hydroxy functional oligoesters within this general 
category will be apparent to those skilled in the art. 
The third type of hydroxy functional oligoester, i.e., those prepared by 
reaction of a hydroxy functional monocarboxylic acid with an epoxide is 
described in U.S. Pat. No. 3,404,018. While the epoxides employed in 
accordance with the teachings of that patent are polyepoxides, oligoesters 
may be prepared in a similar manner to that described therein by employing 
a monoepoxide, such as an alkylene oxide, and a hydroxy functional 
monocarboxylic acid as described therein. 
Among the numerous monomeric polyols which may be employed as the hydroxy 
functional additive are the various short chain glycols of up to and 
including 21 carbon atoms which are useful in preparing the hydroxy 
functional polyesters discussed above. Other conventional polyhydric 
alcohols such as glycerols and sugar alcohols are also among the numerous 
monomeric polyols which will be apparent to those skilled in the art. 
The hydroxy bearing copolymer useful as the hydroxy functional additive may 
be formed from monoethylenically usaturated monomers, with between about 
10 and about 50 weight percent bearing hydroxyl functionality. 
Although one of ordinary skill in the art will recognize that many 
different hydroxy bearing monomers could be employed, the preferred 
hydroxy functional monomers for use in the hydroxy functional resin of the 
invention are C.sub.5 -C.sub.7 hydroxy alkyl acrylates and/or C.sub.6 
-C.sub.8 hydroxy alkyl methacrylates, i.e., esters of C.sub.2 -C.sub.4 
dihydric alcohols and acrylic or methacrylic acids. 
The remainder of the monomers forming the hydroxy functional copolymer, 
i.e., between about 90 and about 50 weight percent of the monomers of the 
copolymer, are other monoethylenically unsaturated monomers. These 
monoethylenically unsaturated monomers are preferably alpha-beta 
olefinically unsaturated monomers, i.e., monomers bearing olefinic 
unsaturation between the two carbon atoms in the alpha and beta positions 
with respect to the terminus of an aliphatic carbon-to-carbon chain. 
Other Materials 
In addition to the above discussed components, other materials may be 
included in the coating compositions of the invention. These include 
materials such as catalysts, antioxidants, U.V. absorbers, surface 
modifiers and wetting agents as well as pigments. 
Surface modifiers or wetting agents are common additives for liquid paint 
compositions. The exact mode of operation of these surface modifiers is 
not known, but it is thought that their presence contributes to better 
adhesion of the coating composition to the surface being coated and helps 
formation of thin coatings, particularly on metal surfaces. These surface 
modifiers are exemplified by acrylic polymers containing 0.1-10 percent by 
weight of a copolymerized monoethylenically unsaturated carboxylic acids 
such as methacrylic acid, acrylic or itaconic acid, cellulose acetate 
butyrate, silicon oils or mixtures thereof. Of course, the choice of 
surface modifiers or wetting agent is dependent upon the type of surface 
to be coated and selection of the same is clearly within the skill of the 
artisan. 
The coating composition of the invention also may include pigments. As 
noted above, the compositions of this invention may include metallic flake 
as a pigment. The amount of pigment in the coating composition may vary, 
but preferably is between about 3 and about 45 weight percent based on the 
total weight of the paint composition. If the pigment is metallic flake, 
the amount ranges from about 1 to about 20 weight percent. 
For many application of the coating composition of the invention, 
particularly high solids composition, it may be desirable to employ flow 
control additives to provide sag free coatings. Among numerous such 
materials NAD's such as described by Porter (S. Porter, Jr., and B. N. 
McBane, U.S. Pat. No. 4,025,474, May 24, 1977) are compatible with these 
oligomers coating compositions. These particle dispersions may be included 
in an amount up to 15% by weight of the total composition. Other types of 
NAD's such as described by D. L. Maker and S. C. Peng (U.S. Pat. No. 
3,814,721, June 4, 1974) also may be included in the paint composition. 
Application Techniques 
The coating composition can be applied by conventional methods known to 
those in the art. These methods include roller coating, spray coating, 
dipping or brushing and, of course, the particular application technique 
chosen will depend on the particular substrate to be coated and the 
environment in which the coating operation is to take place. 
A particularly preferred technique for applying the high solids coating 
compositions, particularly when applying the same to automobiles as 
topcoats, is spray coating through the nozzle of a spray gun. 
High solids paints have in the past caused some difficulty in spray coating 
techniques because of the high viscosity of the materials and resultant 
problems in clogging of spray guns. However, because the compositions of 
this invention demonstrate relatively low viscosity considering the high 
solids content they can be applied by spray coating techniques. 
The invention will be further understood by referring to the following 
detailed examples. It should be understood that the specific examples are 
presented by way of illustration and not by way of limitation. Unless 
otherwise specified, all references to "parts" is intended to mean parts 
by weight.

EXAMPLE 1 
2-ethyl-1,3-hexanediol (2920 g) is placed in a 12 liter flask and is heated 
to 100.degree. C. Methyl-hexahydrophthalic anhydride (3360 g) is added 
dropwise with continuous stirring, while maintaining the temperature at 
about 100.degree. C. The reaction mixture is stirred at this temperature 
for two hours and then 2680 g 1,4-butane diol diglycidyl ether (Araldite 
RD-2, Ciba-Geigy Corp) containing three grams of Cordova Accelerator 
AMC.TM.-2 (Cordova Chemical Company) is added dropwise with continuous 
stirring. After the addition is complete, the reaction mixture is stirred 
at 100.degree. C. for three hours and then it is heated at 165.degree. C. 
for four hours. The molecular weight of the resulting product from gel 
permeation chromatography is found to be M.sub.n =410, M.sub.w =807. 
Sixty two (62) parts of the above hydroxy oligomer and 39 parts of Cymel 
301 (American Cyanamid) are dissolved in 36 parts of butyl acetate and one 
gram of a 50% solution of p-toluene sulfonic acid in 2-proponal are added 
to it. The resulting formulation is applied by spraying to primed steel 
panels to obtain coatings with excellent hardness, adhesion and solvent 
(xylene and methyl ethyl ketone) resistance. 
EXAMPLE 2 
Thirty (30) parts of the hydroxy oligomer from Example 1 are mixed with 
five parts of aluminum flakes (65% in naphtha) in 21 parts of butyl 
acetate. Twenty-one (21) parts of Cymel 325 (American Cyanamid), four 
parts of cellulose acetate and 0.3 parts of butyl acid phosphate are added 
to the above mixture; the resulting formulation is applied by spraying to 
primed steel panels. The panels are baked at 130.degree. C. for 18 minutes 
to obtain silver metallic coatings with excellent hardness, adhesion and 
solvent (xylene and methyl ethyl ketone) resistance. 
EXAMPLE 3 
One hundred and twenty parts of the oligomer from Example 1 are dissolved 
in 145 parts of methyl amyl ketone and 425 parts of titanium dioxide are 
added under agitation to this solution. The resulting mixture is whipped 
with a Cowl's blade at 90 cycles per second for 20 minutes to obtain 
Hegman grind fineness of 7.5. 
Fifty-two parts of the above millbase, 29 parts of the oligomer from 
Example 1, and 23 parts of Cymel 301 (American Cyanamid) are mixed with 25 
parts of butyl acetate. A 50% solution (0.4 parts) of p-toluene sulfonic 
acid in 2-propanol is added to the above mixture and the resulting 
formulation is applied by spraying to primed steel panels. The panels are 
baked at 125.degree. C. for 20 minutes to obtain coatings with excellent 
hardness, adhesion and solvent (xylene and methyl ethyl ketone) 
resistance. 
EXAMPLE 4 
Seven parts of caprolactone based hydroxy ester PCP-0300 (Union Carbide), 4 
parts of hexabutoxymethyl melamine (Cymel 1156, American Cyanamid) and 6 
parts of xylene are added to the formulation described in Example 1. The 
resulting formulation is applied by spraying to primed steel panels which 
are baked at 135.degree. C. for 18 minutes to obtain coatings with 
excellent hardness, adhesion, gloss and solvent (xylene and methyl ethyl 
ketone) resistance. 
EXAMPLE 5 
Nine parts hydroxy polymer Acryloyd OL-42 (Rohm and Haas Chemical Co.) and 
six parts of ethoxymethoxy benzoguanamine (Cymel 1123, American Cyanamid) 
and five parts of methyl amyl ketone are added to the formulation 
described in Example 1. The resulting formulation is applied by spraying 
to primed steel panels which are baked at 135.degree. C. for 17 minutes to 
obtain hard, glossy coatings with excellent adhesion and solvent (xylene 
and methyl ethyl ketone) resistance. 
EXAMPLE 6 
A hydroxy acrylic polymer (M.sub.n =2200) is prepared by solution 
polymerization technique in methyl amyl ketone (60% solids by weight) 
comprising hydroxyethyl acrylate (30%) isobutyl methacrylate (45%) and 
styrene (25%). 
Fifteen parts of this polymer, five parts Cymel 301 and three parts of 
butyl acetate are added to the formulation described in Example 1. The 
resulting formulation is applied by spraying to primed steel panels which 
are baked at 132.degree. C. for 18 minutes to obtain coatings with 
excellent hardness, adhesion and solvent resistance. 
EXAMPLE 7 
By following the procedure described in Example 1, hydroxy oligomer is 
prepared from 168 grams methyl-hexahydrophthic anhydride, 146 grams 
2-ethyl-1,3-hexanediol, 210 grams cycloaliphatic epoxy Araldite CY-178 
(Ciba-Geigy Corp.) and 0.2 grams Cordova Accelerator AMC.TM.-2. 
Sixty parts of the above product, 35 part of Cymel 301 and 0.8 part of 
2-hydroxycyclohexyl p-toluene sulfonate are dissolved in 36 parts of butyl 
acetate. The resulting formulation is applied by spraying to primed steel 
panels which are baked at 135.degree. C. for 20 minutes to obtain coatings 
with excellent hardness, adhesion, gloss and solvent (xylene and methyl 
ethyl ketone) resistance. 
EXAMPLE 8 
Preparation of hydroxy oligomer is carried out as described in Example 1 by 
employing 168 grams methylhexahydrophthalic anhydride, 146 grams 
2-ethyl-1,3-hexanediol, 190 grams bisphenol-A-diglycidyl ether (Epon 828, 
Shell Chemical Co.), 60 grams methyl amyl ketone and 0.35 grams Cordova 
Accelerator AMC.TM.-2. 
Thirty-two parts of the above product and 23 parts of Cymel 325 are 
dissolved in 17 parts of butyl acetate and 0.38 parts of butyl acid 
phosphate are added to the solution. The resulting formulation is applied 
by spraying to a primed steel panel which is baked at 130.degree. C. for 
20 minutes to obtain a coating with excellent hardness, adhesion and 
solvent (xylene and methyl ethyl ketone) resistance. 
EXAMPLE 9 
2-ethyl-1,3-hexanediol (140 g) and methylhexahydrophthalic anhydride (168 
g) are placed in a round bottom flask and heated to 100.degree. C. and 
stirred at this temperature for two hours. Cordova Accelerator AMC.TM.-2 
(0.35 g) is added to the reaction mixture followed by dropwise addition of 
4-vinylcyclohexane dioxide (75 g) with continuous stirring at 100.degree. 
C. The heating is continued for seven hours. 
Fifty-one parts of the above product and 0.3 parts of p-toluene sulfonic 
acid are dissolved in 32 parts of methyl amyl ketone and 39 parts of Cymel 
301 are added to the solution. The resulting formulation is applied by 
spraying to primed steel panels which are baked at 130.degree. C. for 20 
minutes to obtain coatings with excellent hardness, adhesion, gloss and 
solvent (xylene and methyl ethyl ketone) resistance. 
EXAMPLE 10 
Five (5) parts of nonaqueous dispersed particles (41% solids by weight), 
described in U.S. Pat. No. 4,025,474 Example A, are added to the 
composition described in Example 2. The resulting formulation is applied 
by spraying to primed steel panels which are baked at 128.degree. C. for 
19 minutes to obtain silver metallic coatings with excellent hardness, 
adhesion and solvent (xylene and methyl ethyl ketone) resistance. 
In view of this disclosure, many modifications of this invention will be 
apparent to those skilled in the art. It is intended that all such 
modifications which fall within the true scope of this invention be 
included within the terms of the appended claims.