High solids coating compositions

High solids coating compositions comprising a polycaprolactone derivative and a mixture of a methylolated melamine and a low molecular weight polyol; and, optionally, solvent and catalyst. The polycaprolactone derivative used in the coating compositions can be (A) a polycaprolactone polyol; or (B) the reaction product of a polycaprolactone polyol and an anhydride of a polycarboxylic acid; or (C) the reaction product of a polycaprolactone polyol, a polyisocyanate and an anhydride of a polycarboxylic acid; or (D) the reaction product of a polycaprolactone polyol, a diepoxide and an anhydride of a polycarboxylic acid; the polycaprolactone polyol referred to in the above four classes, Types A to D, has an average of at least two hydroxyl groups in the molecule, a hydroxyl number of from about 15 to about 600 and an average molecular weight of from about 290 to about 6,000. The carboxylic acid anhydride mentioned has at least one intramolecular carboxylic anhydride group. The polycaprolactone derivatives are water insoluble.

BACKGROUND OF THE INVENTION 
Governmental regulations have placed ever increasing restrictions on the 
amounts and types of organic volatiles permitted to escape into the 
atmosphere from coatings compositions. Considerable efforts have been 
expended to develop coatings compositions having a minimal amount of 
volatile organic components and this has led to development of powder 
coatings, radiation curable coatings, water borne coatings and high solids 
coatings. In these recent developments the amounts of organic solvents 
present are minimal and consequently there is little or no atmospheric 
pollution. 
In the field of solvent coatings, efforts have been made to reduce the 
amount of volatile solvent present and to increase the amount of component 
that will remain as the coating on the substrate. At a sufficiently high 
concentration of such components one has what is known as a high solids 
coating composition. These are compositions that are applied in liquid 
form and dry to acceptable films without the evaporation of substantial 
quantities of solvents. Thus, a high solids coating composition, such as 
the ones hereinafter described, which would serve to lower atmospheric 
pollution and still produce a good satisfactory coating composition, would 
be of great importance. 
SUMMARY OF THE INVENTION 
It has now been found that certain polycaprolactone derivatives can be used 
in conjunction with methylolated melamines and certain low molecular 
weight polyols to produce high solids coating compositions. The 
polycaprolactone derivatives are hereinafter more fully defined and 
include (A) polycaprolactone polyols; (B) the reaction products obtained 
by reacting a polycaprolactone polyol and an anhydride of a polycarboxylic 
acid to produce a carboxyl modified polycaprolactone adduct which is 
generally water insoluble; or (C) the reaction products obtained by 
reacting a polycaprolactone polyol, a polyisocyanate and an anhydride of a 
polycarboxylic acid to produce a carboxyl modified polycaprolactone 
urethane adduct which is generally water insoluble; or (D) the reaction 
products obtained by reacting a polycaprolactone polyol, a diepoxide and 
an anhydride of a polycarboxylic acid to produce a carboxyl modified 
polycaprolactone-epoxide adduct which is generally water insoluble. The 
high solids coatings compositions can optionally contain an organic 
solvent and a catalyst, where necessary. The preferred compositions are 
those in which the methylolated amine is hexamethoxymethylmelamine. The 
high solids coatings are applied in conventional manner and thermally 
cured to dry films. 
DESCRIPTION OF THE INVENTION 
The polycaprolactone derivatives that are blended with the methylolated 
melamine and the low molecular weight polyol to produce the compositions 
of this invention are of four types, as hereinafter identified. Type A are 
any of the known polycaprolactone polyols that are commercially available 
and that are fully described, for example, in U.S. Pat. No. 3,169,945. As 
described in this patent the polycaprolactone polyols are produced by the 
catalytic polymerization of an excess of a caprolactone and an organic 
polyfunctional initiator having at least two reactive hydrogen atoms. The 
method for producing the polycaprolactone polyols is of no consequence and 
the organic functional initiators can be any polyhydroxyl compound as is 
shown in U.S. Pat. No. 3,169,945. Illustrative thereof are the diols such 
as ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene 
glycol, dipropylene glycol, 1,3-propylene glycol, polyethylene glycol, 
polypropylene glycol, poly(oxyethylene-oxypropylene) glycols, and similar 
polyalkylene glycols, either blocked, capped or heteric, containing up to 
about 40 or more alkyleneoxy units in the molecule, 3 
methyl-1-5-pentanediol, cyclohexanediol, 4,4'methylene-bis-cyclohexanol, 
4,4'-isopropylidene bis-cyclohexanol, xylenediol, 
2-(4-hydroxymethylphenyl) ethanol, 1,4 butanediol, and the like; triols 
such as glycerol, trimethylolpropane, 1,2,6-hexanetriol, triethanolamine, 
triisopropanolamine, and the like; tetrols such as erythritol, 
pentaerythritol, N,N,N',N'-tetrakis(2-hydroxyethyl)ethylene diamine, and 
the like. 
When the organic functional initiator is reacted with the caprolactone a 
reaction occurs that can be represented in its simplest form by the 
equation: 
##STR1## 
In this equation the organic functional initiator is the R"-(OH).sub.x 
compound and the caprolactone is the 
##STR2## 
compound; this can be caprolactone itself or a substituted caprolactone 
wherein R' is an alkyl, alkoxy, aryl, cycloalkyl, alkaryl or aralkyl group 
having up to twelve carbon atoms and wherein at least six of the R' groups 
are hydrogen atoms, as shown in U.S. Pat. No. 3,169,945. The 
polycaprolactone polyols that are used are shown by the formula on the 
right hand side of the equation; they can have an average molecular weight 
of from 290 to about 6,000. The preferred polycaprolactone polyol 
compounds are those having an average molecular weight of from about 290 
to about 3,000, preferably from about 300 to 1,000. The most preferred are 
the polycaprolactone diol compounds having an average molecular weight of 
from about 290 to about 500 and the polycaprolactone triol compounds 
having an average molecular weight of from about 300 to about 1,000; these 
are most preferred because of their low viscosity properties. In the 
formula m is an integer representing the average number of repeating units 
needed to produce the compound having said molecular weights. The hydroxyl 
number of the polycaprolactone polyol can be from about 15 to 600, 
preferably from 200 to 500; and the polycaprolactone can have an average 
of from 2 to 6, preferably 2 to 4, hydroxyl groups. 
Illustrative of Type A polycaprolactone polyols tha can be used as in the 
compositions of this invention, and in the preparation of the Type B, Type 
C and Type D components used in the compositions of this invention, one 
can mention the reaction products of a polyhydroxyl compound having an 
average from 2 to 6 hydroxyl groups with caprolactone. The manner in which 
these type polycaprolactone polyols is produced is shown in U.S. Pat. No. 
3,169,945 and many such compositions are commercially available. In the 
following table there are listed illustrative polycaprolactone polyols. 
The first column lists the organic functional initiator that is reacted 
with the caprolactone and the average molecular weight of the 
polycaprolactone polyol is shown in the second column. Knowing the 
molecular weights of the initiator and of the polycaprolactone polyol one 
can readily determine the average number of molecules of caprolactone (CPL 
Units) that reacted to produce the Type A compound; this figure is shown 
in the third column. 
______________________________________ 
TYPE A POLYCAPROLACTONE POLYOLS 
Average Average No. 
MW of of CPL units 
Initiator polyol in molecules 
______________________________________ 
1 Ethylene glycol 290 2 
2 Ethylene glycol 803 6.5 
3 Ethylene glycol 2,114 18 
4 Propylene glycol 874 7 
5 Octylene glycol 602 4 
6 Decalence glycol 801 5.5 
7 Diethylene glycol 527 3.7 
8 Diethylene glycol 847 6.5 
9 Diethylene glycol 1,246 10 
10 Diethylene glycol 1,998 16.6 
11 Diethylene glycol 3,526 30 
12 Triethylene glycol 
754 5.3 
13 Polyethylene glycol (MW 200)* 
713 4.5 
14 Polyethylene glycol (MW 600)* 
1,398 7 
15 Polyethylene glycol (MW 1500)* 
2,868 12 
16 1,2-Propylene glycol 
646 5 
17 1,3-Propylene glycol 
988 8 
18 Dipropylene glycol 
476 3 
19 Polypropylene glycol (MW 425)* 
835 3.6 
20 Polypropylene glycol (MW 1000)* 
1,684 6 
21 Polypropylene glycol (MW 2000)* 
2,456 4 
22 Hexylene glycol 916 7 
23 2-Ethyl-1,3-hexanediol 
602 4 
24 1,5-Pentanediol 446 3 
25 1,4-Cyclohexanediol 
629 4.5 
26 1,3-Bis(hydroxyethyl)-benzene 
736 5 
27 Glycerol 548 4. 
28 1,2,6-Hexanetriol 476 3 
29 Trimethylolpropane 
590 4 
30 Trimethylolpropane 
750 5.4 
31 Trimethylolpropane 
1,103 8.5 
32 Triethanolamine 890 6.5 
33 Erythritol 920 7 
34 Pentaerythritol 1,219 9.5 
______________________________________ 
*Average molecular weight of glycol. 
The structures of the compounds in the above tabulation are obvious to one 
skilled in the art based on the information given. The structure of 
compound No. 7 is: 
##STR3## 
wherein the variable r is an integer, the sum of r + r has an average 
value of 3.7 and the average molecular weight is 527. The structure of 
compound No. 20 is: 
##STR4## 
wherein the sum of r + r has an average value of 6 and the average 
molecular weight is 1,684. This explanation makes explicit the structural 
formulas of compounds 1 to 34 set forth above. 
As previously indicated, the type A polycaprolactone polyols are used as 
intermediates in the production of the Type B, Type C and Type D 
polycaprolactone derivatives. In producing these three latter types, the 
polycaprolactone polyol is reacted with a polycarboxylic acid anhydride. 
Illustrative thereof one can mention trimellitic anhydride, 
tetrahydrophthalic anhydride, phthalic anhydride, benzophenone 
dicarboxylic acid anhydride, succinic anhydride, maleic anhydride, 
naphthoic anhydride, glutaric anhydride, or any other intramolecular 
anhydride, including those having substituents thereon such as halogen 
atoms, alkyl or alkoxy groups, nitro, carboxyl, aryl, or any other group 
which will not unduly interfere with the reaction. 
For the preparation of the Type B carboxyl modified polycaprolactone 
adducts the amount of polycarboxylic acid anhydride reacted with the 
polycaprolactone polyol can be an amount sufficient to permit reaction 
with all of the hydroxyl groups; however, it is preferred to use an amount 
which is insufficient to react with all of the hydroxyl groups present in 
the polycaprolactone polyol. This amount will vary and can be from 0.1 to 
1 anhydride equivalent for each hydroxyl equivalent or group present in 
the polycaprolactone polyol initially charged to the reaction mixture and 
is preferably from 0.1 to 0.4. In a most preferred instance, one anhydride 
equivalent or anhydride moiety is charged for each nine hydroxyl 
equivalents or groups initially present in the reaction mixture. 
The polycaprolactone polyols are reacted with the polycarboxylic acid 
anhydride at a temperature of about 75.degree. to 200.degree. C., 
preferably about 100.degree. to 160.degree. C. The time required for 
reaction will vary depending upon the particular reactants charged, the 
temperature and the batch size of the reaction mixture, facts which are 
well known to those skilled in the art. Generally it has been found that a 
reaction period in the laboratory of from 15 to 45 minutes at from about 
125.degree. to 175.degree. C. is adequate to produce the initial water 
insoluble carboxyl modified oligomer addition reaction product obtained by 
the reaction of these two intermediates. 
The water insoluble adduct formed at this stage of the reaction is a 
viscous liquid in most instances. However, in some instances it has been 
observed that the product will solidify upon standing at room temperature 
for an extended period of time. This, however, does not detract from its 
further utility. Generally these modified oligomer or adducts are water 
insoluble but solvent soluble. 
For the preparation of the Type C carboxyl modified polycaprolactone 
urethane adducts, the abovedefined polycaprolactone polyols and anhydrides 
are used in conjunction with a polyisocyanate. 
The polyisocyanates that can be used in this invention are well known to 
those skilled in the art and should not require detailed description 
herein. Any of the polyisocyanates can be used alone or in admixture with 
other isocyanates including the monoisocyanates. Illustrative thereof one 
can mention methyl isocyanate, ethyl isocyanate, chloroethyl isocyanate, 
chloropropyl isocyanate, chlorohexyl isocyanate, chlorobutoxypropyl 
isocyanate, hexyl isocyanate, phenyl isocyanate, the o-, m-, and 
p-chlorophenyl isocyanates, benzyl isocyanate, naphthyl isocyanate, 
o-ethylphenyl isocyanate, the dichlorophenyl isocyanates, methyl 
isocyanate, butyl isocyanate, n-propyl isocyanate, octadecyl isocyanate, 
3,5,5-trimethyl-1-isocyanato-3-isocyanatomethyl-cyclohexane, 
di(2-isocyanatoethyl)-bicyclo(2.2.1)-hept-5-ene-2,3-dicarboxylate, 
2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 4,4'-diphenylmethane 
diisocyanate, dianisidine diisocyanate, tolidine diisocyanate, 
hexamethylene diisocyanate, the m- and p-xylylene diisocyanates, 
tetramethylene diisocyanate, dicyclohexyl-4,4'-methane diisocyanate, 
cyclohexane-1,4-diisocyanate, 1,5-naphthylene 
diisocyanate,4,4'-diisocyanate diphenyl ether, 2,4,6-triisocyanate 
toluene, 4,4',4"-triisocyanate triphenyl methane, 
diphenylene-4,4-diisocyanate, the polymethylene polyphenylisocyanates, as 
well as any of the other organic isocyanates known to the average skilled 
chemist. 
The amount of isocyanate used can be an amount sufficient to permit 
reaction of the isocyanato group with up to about 0.9 equivalent of the 
total number of hydroxyl equivalents present. Thus, from 0.025 to 0.9 
isocyanato equivalent is reacted per hydroxyl equivalent, preferably from 
0.04 to 0.5 isocyanato equivalent per hydroxyl equivalent, and most 
preferably from 0.04 to 0.25 isocyanato equivalent per hydroxyl equivalent 
initially charged. 
The amount of polycarboxylic acid anhydride reacted with the 
polycaprolactone polyol can be an amount sufficient to react with all the 
residual unreacted hydroxyl groups; however, it is preferred to use an 
amount which is insufficient to react with all of the residual hydroxyl 
groups present in the polycaprolactone polyol after its reaction with the 
isocyanate. This amount will vary and can be from 0.1 to 1 anhydride 
equivalent for each unreacted hydroxyl equivalent or group present in the 
polycaprolactone derivative in the reaction mixture. It is preferably from 
0.1 to 0.4 and, in a most preferred instance, one anhydride equivalent or 
anhydride moiety is charged for each nine unreacted hydroxyl equivalents 
or groups present in the reaction mixture. 
The reaction temperature when this isocyanate derivative is initially 
reacted with this polycaprolactone polyol can be from about room 
temperature to about 75.degree. C. The temperature is then raised when 
this urethane derivative is subsequently reacted with the polycarboxylic 
acid anhydride and this temperature is the same as that which is used when 
all three components are initially charged together. The reaction of any 
mixture with the anhydride is carried out at a temperature of from about 
75.degree. to 200.degree. C., preferably from about 100.degree. to 
140.degree. C. The time required for reaction will vary depending upon the 
particular reactants charged, the temperature and the batch size of the 
reaction mixture, facts which are well known to those skilled in the art. 
Generally it has been found that a reaction period in the laboratory of 
from 15 to 45 minutes at from about 125.degree. to 150.degree. C. is 
adequate to produce the initial water insoluble carboxyl modified urethane 
oligomer addition reaction product obtained by the reaction of these 
intermediates. 
The water insoluble urethane adduct formed at this stage of the reaction is 
a viscous liquid in most instances. However, in some instances the product 
may solidify upon standing for an extended period of time. This, however, 
does not detract from its further utility. Generally these carboxy 
modified urethane oligomers or adducts are water insoluble but solvent 
soluble. 
For the preparation of the Type D carboxyl modified 
polycaprolactone-epoxide adducts, the above defined polycaprolactone 
polyols and anhydrides are used in conjunction with a diepoxide. 
The diepoxides that can be used in this invention are well known to those 
skilled in the art and are fully described in U.S. Pat.No. 3,027,357, U.S. 
Pat. No. 2,890,194 and U.S. Pat. No. 2,890,197. Of particular interest is 
that portion of U.S. Pat. No. 3,027,357 beginning at column 4, line 11 to 
column 7, line 38, which portion and disclosure is specifically 
incorporated herein by reference. Among some of the specific illustrative 
diepoxides disclosed therein one can mention 
3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexane carboxylate, 
bis(3,4-epoxy-6-methylcyclohexylmethyl) adipate, 
bis(2,3-epoxy-cyclopentyl) ether, vinyl cyclohexene dioxide, 
2-(3,4-epoxycyclohexyl)-5,5-spiro-(2,3-epoxycyclohexane)-m-dioxane, 
bis(3,4-epoxycyclohexylmethyl) adipate, and the like. 
The amount of polycarboxylic acid anhydride reacted with the 
polycaprolactone polyol is an amount which is insufficient to react with 
all of the hydroxyl groups initially present in the polycaprolactone 
polyol or formed in the polycaprolactone-epoxide adduct. This amount will 
vary and can be from 0.1 to about 0.5 anhydride equivalent for each 
unreacted hydroxyl equivalent or group present in the polycaprolactone 
portion of the reaction mixture. 
The reactions are conducted at a temperature of from about 75.degree. to 
200.degree. C., preferably from about 100.degree. to 160.degree. C. The 
time required for reaction will vary depending upon the particular 
reactants charged, the temperature and the batch size of the reaction 
mixture, facts which are well known to those skilled in the art. Generally 
it has been found that a reaction period in the laboratory of from 15 to 
120 minutes at from about 125.degree. to 175.degree. C. is adequate to 
produce the initial water insoluble carboxyl modified 
polycaprolactone-epoxide oligomer addition reaction product obtained by 
the reaction of the intermediates. 
The water insoluble polycaprolactone-epoxide adduct formed at this stage of 
the reaction is a viscous liquid in most instances. However, in some 
instances the product may solidify upon standing for an extended period of 
time. This, however, does not detract from its further utility. Generally 
these modified polycaprolactone-epoxide oligomers or adducts are water 
insoluble but solvent soluble. 
While applicants have not fully established the structures of the Type B, 
Type C and Type D adducts, it has been theorized that the reactions can 
proceed along the following route: 
##STR5## 
In the above reaction schemes the unit 
##STR6## 
represents a polycaprolactone triol, OCNRNCO represents a diisocyanate and 
X is an integer having a value of 0 to 4. While this theoretical 
explanation is presented, applicants do not intend to be bound by any 
theory. 
In a typical reaction for the production of the Type B adducts one normally 
charges a polycaprolactone polyol and the polycarboxylic acid anhydride to 
a reaction vessel and heats the mixture to a temperature of from about 
125.degree. to 175.degree. C. for a period of about 20 to 30 minutes. This 
produces a water insoluble carboxyl modified polycaprolactone oligomer or 
adduct. 
In a typical embodiment for the production of the Type C adducts one can 
react the polycaprolactone polyol and the polyisocyanate at a temperature 
up to about 75.degree. C. and then add the carboxylic acid anhydride and 
react at 75.degree. C. to 200.degree. C. to produce the water insoluble 
methane adduct. In a second embodiment all of the reactants are initially 
charged together and the reaction is heated and completed at a temperature 
of from 75.degree. C. to 200.degree. C. 
It is customary to use any of the known urethane-forming reaction catalysts 
during the isocyanate reaction with the polyol. These are well known and 
any of the catalysts can be used. Illustrative thereof are dibutyltin 
dilaurate, stannous octoate, triethylenediamine, triethylamine, the known 
tin salt catalysts, and the like. 
In a typical embodiment for the production of the Type D adducts according 
to Route I, one can react the polycaprolactone polyol with the diepoxide 
at the indicated temperature to produce the Water Insoluble 
Polycaprolactone-Epoxide I or variants thereof. In some instances one may 
wish to react up to two of the hydroxyl on each polycaprolactone triol. 
This intermediate compound is then reacted in Step 2 with a carboxylic 
acid anhydride to form the second Water Insoluble Polycaprolactone-Epoxide 
II shown above. 
In a typical embodiment according to Route II, one can initially react the 
polycaprolactone polyol with a carboxylic acid anhydride to obtain the 
Water Insoluble Polycaprolactone Adduct shown in Step 1. This derivative 
is then reacted, as shown in Step 2, with the diepoxide to produce the 
Water Insoluble Polycaprolactone-Epoxide Adduct I. 
In the schematics shown above specific ratios and compounds were employed 
for illustrative purposes only. It is apparent, in view of our complete 
description, that these can be modified within the ranges disclosed in 
this application. The Types B, C and D water insoluble adducts shown above 
are generally neutralized with an inorganic or organic base to a pH of 
from about 7 to 9. The preferred bases are the organic amines such as 
butylamine, morpholine, triethylamine, diethylamine, or any other known 
amine with the preferred being the tertiary amines. 
As is known, catalysts are used during the reaction of the diepoxide with 
the carboxyl group. The suitable catalysts for use in this invention are 
those conventionally used and the amounts are also known to those skilled 
in the art. Illustrative thereof one can mention stannous octoate, 
benzildimethylamine, tris(dimethylaminomethyl)phenol, triethylenediamine, 
tributylphosphine, triethylene, uranyl nitrate hexahydrate, and the like. 
The high solids coatings compositions of this invention contain a 
methylolated melamine. These compounds are well known and many are 
available commercially. Those suitable for use can be represented by the 
general formula: 
##STR7## 
wherein X is hydrogen or --CH.sub.2 OCH.sub.3 and wherein at least two of 
the X substituents are --CH.sub.2 OCH.sub.3 groups. The preferred melamine 
derivatives are the highly methylolated melamines, with 
hexamethoxymethylmelamine most preferred. Other amino resins that can be 
used include the urea and benzoguanamine resins. 
The third necessary component for the compositions of this invention is a 
non-volatile low molecular weight polyol containing from 2 to 6, 
preferably 2 to 4 hydroxyl groups. These non-volatile low molecular weight 
polyols can have a molecular weight of from 62 to about 1000. They can be 
aliphatic, cycloaliphatic or aromatic in nature. Illustrative thereof one 
can mention ethylene glycol, diethylene glycol, triethylene glycol, 
propylene glycol, dipropylene glycol, neopentyl glycol, butylene glycol, 
2,2-dimethyl-3-hydroxypropyl 2,2-dimethyl-3-hydroxypropionate, 
2,3-dibromo-1,4-but-2-ene diol, bisphenol-A and the ethylene oxide and/or 
propylene oxide adducts thereof, 2,2-dihydroxymethylpropionic acid, 
trimethylol ethane, trimethylol propane, pentaerythritol, 
dipentaerythritol, glycerine, sorbitol, hydrogenated bisphenol-A; 
1,1-dihydroxy methane cyclohexane, 2,2'-dihydroxymethylbicyclo 
[2.2.1]heptane, 1,5-pentane diol, decane diol, and the like. Many other 
non-volatile low molecular weight diols having a molecular weight of from 
62 to about 1000 are known and can be used; the above enumeration is 
illustrative only. 
The concentration of the polycaprolactone derivative of Types A to D in the 
high solids coatings compositions of this invention can be from 20 to 80 
weight percent, preferably from 25 to 50 weight percent, and most 
preferably from 30 to 35 weight percent of the total weight of said 
derivative plus combined mix, as the term combined mix is hereafter 
defined. 
The term "combined mix" defines the mixture of the methylolated melamine 
compounds plus the low molecular weight polyol compounds herebefore 
defined. The concentration of said combined mix in the high solids 
coatings compositions of this invention can be from 80 to 20 weight 
percent, preferably from 75 to 50 weight percent and most preferably from 
70 to 65 weight percent of the total weight of polycaprolactone derivative 
plus combined mix. In this combined mix the concentration of the 
methylolated melamine is from 40 to 90 weight percent, preferably from 50 
to 75 weight percent based on the weight of the combined mix. 
The coating compositions can also contain an organic solvent and a catalyst 
as optional components. Any of the conventional solvents used in the 
coatings industry can be used at a concentration preferably below 30 
weight percent of the total weight of the coating composition. While 
larger amounts could conceivably be used, the use of larger amounts would 
destroy the high solids nature of the coating; solvents are generally 
added in the small amounts indicated to improve flowability during 
application of the coating composition to the substrate. 
In some instance an acid catalyst might be desired to improve the 
efficience of the melamine crosslinking reaction during curing. The 
concentration of the catalyst can vary from zero to about 10 weight 
percent based on the total weight of the coating composition. The 
particular catalyst used and its concentration are dependent to a degree 
upon its catalytic activity and the specific components present in the 
coatings composition. These catalysts are known to those skilled in the 
art and include hydrochloric acid, sulfuric acid, p-toluene sulfonic acid, 
dodecylbenzene sulfonic acid, phosphoric acid and its alkyl derivatives, 
maleic acid, trimellitic acid, phthalic acid, succinic acid, and the like. 
The coatings compositions can also contain pigments, fillers, and other 
additives conventionally present in coatings compositions in their 
conventional quantities. The particular ones selected are of no 
consequence to the basic invention. In preparing the coatings 
compositions, the ingredients are mixed by the conventional procedures 
used in the production of paints, inks or coatings compositions. These 
procedures are so well known to those skilled in the art that they do not 
require further discussion here. 
The coatings compositions are applied to a surface or substrate by 
conventional means and then thermally cured by heating at a temperature of 
about 125.degree. to 250.degree. C, preferably from 150.degree. to 
200.degree. C. for a period of time sufficient to obtain a dry film. 
Generally, this time will range from about one to 30 minutes, preferably 
from 10 to 20 minutes. The components present in a particular high solids 
coating composition will determine the temperature and time that will be 
required to obtain an adequate cure and a good film coating. 
The coatings compositions of this invention are high solids coatings 
compositions and they can contain as much as 90 weight percent or more 
solids therein. Generally the total solids content of the coatings 
compositions of this invention range from about 70 to 90 weight percent of 
the total weight of the coating composition. 
The coatings compositions were evaluated according to the following 
procedures. Crosshatch adhesion refers to a test using 10 parallel single 
edge razor blades to scribe test films with 2 sets of perpendicular lines 
on a crosshatch pattern. Ratings are based on the amount of film removed 
after applying and subsequently pulling a contact adhesive tape away 
(Scotch Brand 606) from the surface of the scribed coating at a 90.degree. 
angle in a fast rapid movement. It is important to carefully apply and 
press the tape to the scribed coating to eliminate air bubbles and provide 
a good bond because adhesion is reported in percent of film remaining on 
the substrate with a 100 percent rating indicating complete adhesion of 
the film to the substrate. 
Solvent resistance is a measure of the resistance of the cured film to 
attack by acetone and is reported in the number of rubs or cycles of 
acetone soaked cheesecloth required to remove one half of a film from the 
test area. The test is performed by stroking the film with an acetone 
soaked cheesecloth until that amount of film coating is removed. The 
number of cycles required to remove this amount of coating is a measure of 
the coating solvent resistance. 
Reverse impact measures the ability of a given film to resist rupture from 
a falling weight. A Gardner Impact Tester using an eight pound dart is 
used to test the films cast and cured on the steel panel. The dart is 
raised to a given height in inches and dropped on to the reverse side of a 
coated metal panel. The inches times pounds, designated inch-pound, 
absorbed by the film without rupturing is recorded as the films 
reverse-impact resistance. 
In this application the following definitions describe the particular 
compounds that are used in the examples: 
Silicone Surfactant I is 
##STR8## 
Polyol A is a polycaprolactone diol having an average molecular weight of 
530 and an average hydroxyl number, measured in milligrams of potassium 
hydroxide per gram, of 212. 
Polyol B is a polycaprolactone diol having an average molecular weight of 
830 and an average hydroxyl number of 135. 
Polyol C is a polycaprolactone diol having an average molecular weight of 
1,250 and an average hydroxyl number of 90. 
Polyol D is a polycaprolactone diol having an average molecular weight of 
2,000 and an average hydroxyl number of 56. 
Polyol E is a polycaprolactone triol having an average molecular weight of 
540 and an average hydroxyl number of 310. 
Polyol F is the reaction product of a mixture of Polyol E and a 
polycaprolactone triol having an average molecular weight of 300 and an 
average hydroxyl number of 560 reacted with 3,4-epoxycyclohexane 
carboxylate, said Polyol F having a hydroxyl number of 340 and an average 
molecular weight of about 900. 
Polyol G is a polycaprolactone triol having an average molecular weight of 
300 and an average hydroxyl number of 560.

The following examples further serve to define this invention. 
EXAMPLE 1 
A coating composition was prepared containing 8 grams of Polyol E, 1 gram 
of hexamethoxymethylmelamine having less than about 0.5 weight percent 
methylol groups, 1 gram of trimethylolpropane, 5 grams of methyl ethyl 
ketone and 0.02 gram of para-toluenesulfonic acid. The mixture was mixed 
until homogeneous and the coating was applied on steel panels using a No. 
40 wire wound rod. The coating was cured at 350.degree. F. for 5 minutes 
and the dry film had good gloss and reverse impact resistance, solvent 
resistance was poor when exposed to acetone. 
EXAMPLES 2 TO 6 
In this series of examples coating formulations were produced containing 
the components described in the table below. In addition, twenty parts of 
methyl ethyl ketone per hundred parts of solids were added in preparing 
the liquid formulation. These coatings were applied to steel panels using 
a No. 60 wire wound rod and they were cured at 350.degree. F. for 5 
minutes. The formulations in weight percentages and the properties of the 
dry film coatings are set forth below. The formulations contained 0.4 
weight percent of a mixture of methyldiethanol amine and 
para-toluenesulfonic acid in 50 percent isopropanol as catalyst. 
______________________________________ 
Example 2 3 4 5 6 
______________________________________ 
Polyol B 76 41 33 28 24 
Hexamethoxymethyl- 
melamine 24 39 42 44 46 
*Esterdiol-204 O 20 25 28 30 
Sward hardness 12 14 18 30 30 
glass = 100% 
Reverse impact, 
25 125 200 125 25 
in.lb. 
______________________________________ 
*2,2-dimethyl-3-hydroxypropyl 2,2-dimethyl-3-hydroxypropionate 
The data indicate that hardness of the coating film increases as the 
concentrations of hexamethoxymethylmelamine and the Esterdiol-204 
increase. It also indicates that impact resistance properties are 
optimized at a polycaprolactone polyol concentration in the range of 30 to 
35 weight percent. 
EXAMPLES 7 TO 11 
A series of coating compositions was produced having the formulations 
described in the following table. In these formulations the catalyst was 
the same used in Examples 2 to 6. In addition, 20 parts of toluene per 
hundred parts of solids was added in preparing the liquid coating 
compostions. These coating compositions were applied to steel panels using 
a No. 40 wire wound rod and cured at 350.degree. F. for 5 minutes. The 
properties of the coatings are also set forth below. 
______________________________________ 
Example 7 8 9 10 11 
______________________________________ 
Polyol A, g 58 42 36 31 24 
Hexamethoxymethyl- 
melamine, g. 42 42 44 45 48 
Esterdiol-204, g. 
O 16 20 24 28 
Sward hardness, 
glass = 100% 10 12 14 26 26 
Reverse impact, 
75 125 150 100 15 
in.lb. 
______________________________________ 
The coated films had good adhesion and solvent resistance properties. Again 
it was observed that reverse impact properties were at a maximum when 
approximately 35 weight percent of the polycaprolactone polyol was present 
in the coating composition. 
EXAMPLE 12 
A coating composition was produced containing 16.3 grams of Polyol C, 20.4 
grams of hexamethoxymethylmelamine, 13.3 grams of Esterdiol-204 and 0.5 
gram of the catalyst used in Examples 2 to 6. This coating composition was 
applied to steel panels using a No. 40 wire wound steel rod and cured at 
350.degree. F. for 5 minutes. There was produced a smooth, glossy, dry 
film having a Sward hardness of 20 and a reverse impact of 125 in.lb. 
EXAMPLE 13 
A coating composition was produced containing 16.6 grams of Polyol D, 19.7 
grams of hexamethoxymethylmelamine, 13.7 grams of Esterdiol-204 and 0.5 
gram of the same catalyst used in Examples 2 to 6. This coating 
formulation was applied to steel panels using a No. 40 wire wound rod and 
cured at 350.degree. F. for 5 minutes. The dry film had a Sward hardness 
of 22 and a reverse impact resistance of 150 in.lbs. 
EXAMPLE 14 
A coating composition was produced containing 46.5 grams of Polyol B, 36.5 
grams of hexamethoxymethylmelamine, 15.7 grams of dimethanol 
tricyclodecane, 40 grams of titanium dioxide, 2 grams of a 50 percent 
isopropanol solution of a mixture of methyl diethanolamine and 
para-toluenesulfonic acid, 20 grams of methyl isobutyl ketone and 0.1 gram 
of Silicone Surfactant I. This mixture was rolled in a ball mill overnight 
to produce a white coating composition that was sprayed on to steel panels 
and cured at 350.degree. F. for 5 minutes. The dry film was glossy, 
flexible and of good impact. 
EXAMPLE 15 
A reaction flask equipped with a stirrer, thermometer and nitrogen inlet 
tube was charged with 1,200 grams of Polyol E, 1,200 grams of Polyol G and 
600 grams of phthalic anhydride. The mixture was heated under nitrogen for 
60 minutes at 140.degree. C. An amber colored, viscous liquid having an 
acid number of 78 mgm KOH/gram was obtained that was neutralized to a pH 
of 8.2 with 378 grams of N,N-dimethyl ethanolamine. 
A 6.8 grams portion of the neutralized carboxyl modified polycaprolactone 
adduct reaction product mixture was blended with 10.6 grams of 
hexamethoxymethylmelamine, 2.6 grams of 2,2-dimethyl-3-hydroxypropyl 
2,2-dimethyl-3-hydroxypropionate and 5 grams of butyl acetate as solvent 
to produce a coating composition. This high solids coating composition was 
applied to a steel panel using a No. 60 wire wound rod and cured at 
350.degree. F. for 20 minutes to yield a smooth, glossy, dry film having 
good acetone resistance properties. 
EXAMPLE 16 
A reaction flask, as described in Example 15, was charged with 300 grams of 
Polyol G and 0.35 gram of dibutyltin dilaurate. After heating to 
50.degree. C., 30 grams of hydrogenated tolylene diisocyanate were added 
in a dropwise manner. Then 58 grams of phthalic anhydride were added and 
the mixture was heated under nitrogen at 130.degree. C. for 30 minutes. An 
amber colored, viscous liquid having an acid number of 57 mgm KOH/gram was 
obtained that was neutralized with 32.6 grams of N,N-dimethyl 
ethanolamine. 
A 6.8 grams portion of the neutralized carboxyl modified polycaprolactone 
urethane adduct reaction product mixture was blended with 10.6 grams of 
hexamethoxymethylmelamine, 2.6 grams of 2,2-dimethyl-3-hydroxypropyl 
2,2-dimethyl-3-hydroxypropionate and 5 grams of butyl acetate as solvent. 
This high solids coating composition was applied to a steel panel using a 
No. 60 wire wound rod and cured at 350.degree. F. for 20 minutes to yield 
a smooth, glossy, dry film having good acetone resistance properties. 
EXAMPLE 17 
A reaction flask, as described in Example 15, was charged with 360 grams of 
Polyol F and 40 grams of phthalic anhydride. After heating at 130.degree. 
F. for 30 minutes an amber colored, viscous liquid having an acid number 
of 39 mgm KOH/gram was obtained; this was neutralized with 25 grams of 
morpholine. 
A 6.8 grams portion of the neutralized carboxyl modified polycaprolactone 
adduct reaction product mixture was blended with 10.6 grams of 
hexamethoxymethylmelamine, 2.6 grams of 2,2-dimethyl-3-hydroxypropyl 
2,2-dimethyl-3-hydroxypropionate and 5 grams of butyl acetate as solvent. 
This high solids coating composition was applied to a steel panel using a 
No. 60 wire wound rod and cured at 350.degree. F. for 20 minutes to yield 
a smooth, glossy, dry film having good resistance to acetone. 
EXAMPLE 18 
A coating composition was produced containing 6.8 grams of Polyol F, 10.6 
grams of hexamethoxymethylmelamine, 2.6 grams of 
2,2-dimethyl-3-hydroxypropyl 2,2-dimethyl-3-hydroxypropionate, 5 grams of 
butyl acetate, 0.4 grams of maleic anhydride and 0.4 gram of N,N-dimethyl 
ethanolamine. This high solids coating composition was applied to a steel 
panel using a No. 60 wire wound rod and cured at 350.degree. F. for 20 
minutes to yield a smooth, glossy, dry film having good resistance to 
acetone. 
EXAMPLE 19 
A coating composition was produced containing 5.6 grams of the neutralized 
carboxyl modified polycaprolactone adduct reaction product mixture of 
Example 15, 8.4 grams of hexamethoxymethylmelamine, 6 grams of the adduct 
diol reaction product of 3 moles of ethylene oxide with one mole of 
2,2-bis(4-hydroxyphenyl)propane and 5 grams of butyl acetate. This high 
solids coating composition was applied to a steel panel using a No. 60 
wire wound rod and cured at 350.degree. F. for 20 minutes to yield a 
smooth, glossy, dry film having good acetone resistance.