CA1095053A - Mixed ethers of tetramethylol glycoluril - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE

New glycoluril derivatives of the formula:

Description

~O~SOS3 This application is divided out of our copending application Serial No. 268 635 which relates to a composition of a partially or fully alkylated glycoluril, a non-self-crosslinking polymeric material containing as a reac-tive group one or more carboxyl groups, alcoholic hydroxy groups, or amide groups, such groups being present in an amount of from 0.5 % to 25% by weight based on the weight of said polymeric material, and from 0.5% to 5.0% by weight, based on the total weight of said glycoluril and polymeric material.
The composition may be in the form of an aqueous dispersion if the polymeric material is water-dispersible or organic solvent soluble if the polymeric material is organic solvent soluble.
This invention relates to certain novel mixed ethers of tetramethylol glycoluril which can be used in compositions which are similar to those of our Application Serial No. 268 635.
Organic metal finishes have been commercially available for a great number of years. Coatings from natural materia]s such as linseed oil were superceded in time by synthetic po~ymeric materials. Frequently these earlier materials were dissolved in organic solvents and deposited by any of a number of conventional methods on metallic substrates and dried or baked to produce the desired coating on the metal substrates. Some of these earlier coating compositions were not as hard nor as chemically resistant to solvents and acids as desired. As a consequence, further developments produced blends of crosslinkable polymeric materials which were used in conjunction with a cross-linking agent which, when the combination was used as a coating on a metallic substrate and then baked so as to convert the crosslinkable polymeric material and the crosslinking agent to a thermoset state, provided a hard, chemical .

' ` ~

~O~ S3 resistant film. Presently, the most commonly used crosslinking agents are based on triazines such as melamine, benzoguanamine or the ureas, including urea per se and thiourea. However, these crosslinking agents do not fill all of the needs of the present time and newly developing coating applications.
These newly developing coating applications require in certain instances superior full performance than that which is achievable at the present time with the already known crosslinking agents. In more recent times, because of ecological considerations, it is desirable to furnish aqueous systems which provide an aqueous dispersion of the blended materials although such provision is not intcnded to replace entirely the solvent systems.
The invention of our copending application Serial No. 268 635 is in the coating resin field and provides an organic solvent solution or an aqueous dispersion of a mixture or blend of certain partially or fully alkyl-ated glycoluril derivatives and certain organic solvent or water dispersible non-gelled, non-self-crosslinking polymeric materials that are acid catalyzed and which can be deposited on a substrate by any one of a number of methods, including coating, spraying, dipping,brushing, roller coating, and electro-coating and the like and after the application of the coating composition to the metal substrate, the coated substrate is baked at the appropriate tem-perature wherein the crosslinking agent through the assistance of the acidcatalyst, crosslinks with the polymeric material and produces a hard, chemical resistant film.
Our copending application Serial No. 268 635 provides an organic solvent soluble or an aqueous dispersion of a mixture of from about 2% to about 50%, by weight, of (A) a glycoluril derivative having the structural 109S~53 unit:

R2 --l \ ~ r~ N ~ (CH20R)n / ~ - ~ (CN2)4 (n+m wherein n is an integer from 1 to 4 inclusive; m is 0, 1 or 2; each R is 30 individually either hydrogen or an alkyl radical having from 1 to 6 carbon atoms inclusive; provided that when m is 0, and n is 4, each R is an identical alkyl radical or at least one R is hydrogen; R2 and R3 are separately hydrogen or an alkyl radical having from 1 to 6 carbon atoms inclusive or a phenyl radical; and correspondingly from about ~8% to about 50%, by weight, of (B) an organic solvent soluble or a water dispersible non-gelled, normally non-self-crosslinking (under normal baking conditions) polymeric material which polymeric material contains as reactive groups, any one or more of carboxyl groups, alcoholic hydroxyl groups or amide groups wherein the amount of said groups is at least about 0.5%, by weight, and not more than about 25%, by weight, based on the total weight of said polymeric material; and (C) from abo~lt 0.05% to 5.0%, by weight, of an acid catalyst based on the total weight of (A) and (B), wherein said reactive groups of (B) are heat reactive with (A) and wherein said percentages of (A) and ~B), by weight, total 100% and ::: , .:
' . ~ ' 10~5~)S3 are based on the total solids weight of (A) and (B). Normal baking conditions for these coatings are generally 200 C. or less for 30 minutes or less.
According to one aspect of the present invention there is provided a mixed ether of a tetramethylol glycoluril of the formula:
_ 2 1 -0- _ N _ (CH20R)n N - r (CH20R4)4 _ n wherein n is an integer from 1 to 3 inclusive; R and R4 are individually different alkyl radicals of 1 to 6 carbon atoms inclusive; and R2 and R3 are separately hydrogen or an alkyl radical having from 1 to 6 carbon atoms inclusive or a phenyl radical.
The mixed ethers of this invention can be used in coating composi-tions similar to those which are the subject of our Application Serial No.
268 635.
According to another aspect of the invention, therefore, there is provided a coating composition comprising a mixture of from about 2% to about 50% by weight of (A) a glycoluril derivative having the following structural formula:

, l~SOS3 ~ ~ (CH20R)n ¦ ¦ _ - (CH20R4)4 wherein n is an integer from 1 to 3 inclusive; R and R4 are individually different alkyl radicals having from 1 to 6 carbon atoms inclusive; R2 and R3 are separately hydrogen or an alkyl radical having from 1 to 6 carbon atoms inclusive or a phenyl radical; and correspondingly from about 98% to about 50% by weight; of (B) a water dispersible, normally non-self-cross-linking polymeric material having as reactive groups, any one or more of carboxyl groups, alcoholic hydroxyl groups or amide groups wherein the amount of said groups is at least about 0.5% by weight, and not more than about 25~, by weight, based on the total weight of said polymeri.c material; and (C) from about 0.05% to 5.0%, by weight, of an acid catalyst based on the total weight of (A) and (B), wherein said reactive groups of (B) are heat reactive with (A) and wherein said percentages of (A) and (B), by weight, total 100%
and are based on the total solids weight of (A) and ~B).
In the last ten years, dramatic changes have taken place in the organic coating technology. There has been increased emphasis on pollution free coating systems such as aqueous emulsion, water-borne coatings, electro-coating, powder coatings and ultra-violet light curable coatings. The exist-in~ crosslinking agents based on melamine, the guanamines, including ben30-guanamine, or urea and substituted ureas do not fill all the needs of the :

'' ~l0~50S3 present coating market. The glycoluril derivatives used in the present invention are a new class of crosslinking agents, the starting material of which is glycoluril and is also known as acetylene diurea which is prepared by reacting two moles of urea with one mole of the glyoxal. The glycoluril can be methylolated~ partially or fully, by reacting one mole of glycoluril with between one and four moles of formaldehyde. When the glycoluril is fully methylolated, it is identified as tetramethylol glycoluril. me methylo-lated glycolurils can be alkylated, either partially or fully, depending on whether or not the glycoluril is partially or fully methylolated and depend-ing further on whether or not partial or fully alkylation is desired. If thetetramethylol glycoluril is reacted with a selected amount of a monohydric aliphatic or cycloaliphatic alcohol containing from one to six carbon atoms, one can produce, for instance, the tetra(alkoxy methyl) glycoluril or partially alkylated glycolurils. These monohydric alcohols may be primary or secondary alcohols. The monohydric alcohols that can be used to achieve this alkylation may be methanol, ethanol, n-propanol, n-butanol, n-amyl alcohol, n-hexyl alcohol, isobutanol, isopropanol, sec-butanol, cyclohexanol and the like.
Some of these glycoluril derivatives are already identified in the chemical literature. The present examples illustrate the preparation of mixed ethers of tetramethylol glycoluril in accordance with this invention and the preparation of other glycoluril derivatives which can be used in the compositions claimed in ourapplication Serial No. 268 635. In the examples all parts are parts by weight unless otherwise indicated. These examples are set forth primarily for the purpose of illustration.

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~lO~S~53 Preparation of Glycoluril Into a suitable reaction vessel equipped with stirrer, thermometer, and reflux condenser, there was introduced 765 parts of urea and 875 parts of water. To this slurry, 282 parts of concentrated sulfuric acid were charged and the mixture was heated to 70 C. At 70 C~, 605 parts of glyoxal (40% aqueous solution and free from formaldehyde) were added slowly to the clear solution such that the reaction temperature is maintained between 75-80 C. After the addition of glyoxal, the reaction mixture was held at 75 C.
for one hour and then cooled. The separated crystalline glycoluril was fil-tered and washed with water and a dilute caustic aqueous solution. Theglycoluril obtained after drying has a m.p. of 298 -300 C. and the yield was 88% (525 parts).
Preparation of Tetramethylol Glycoluril Into a suitable reaction vessel equipped with a stirrer, thermometer, and reflux condenser, there was introduced 688 parts (10 moles) of aqueous formaldehyde (44%), and the pH was adjusted to 8.7 with 22 parts of 0.5N NaOH
solution. To this solution, 284 parts (2 moles) of glycoluril were addedat 40 C. During the reaction, the temperature was allowed to rise up to 55 C.
At this stage, most of the glycoluril went into solution. After about 15 minutes, the pH was adjusted to 8.0 with five parts of 0.5N NaOH. A clear pale yellow colored solution was obtained. The clear solution was distilled at 50 C. under reduced pressure to remove water, until the reaction vessel content was about 640 parts. The syrup in the vessel was poured into 800 parts of methanol. The white crystalline precipitate was filtered and dried.
The total yield of the tetramethylol glycoluril was 483 parts (92% yield) and , -:

~095()53 Preparation of Tetrabutox~m~ Gl~coluril Into a suitable reaction vessel equipped with a stirrer, thermometer, and reflux condenser there was introduced 1,000 parts (13.5 moles) of n-butanol and 7.0 parts of concentrated nitric acid and 20 parts of water.
To this mixture was added 200 parts of tetramethylol glycoluril (0.76 mole) and the reaction mixture was stirred at 40 C. for two hours. me reaction mixture became a clear solution. It is then distilled at reduced pressure between 45-50 C. to remove the butanol/water azeotrope mixture. After 260 parts of the n-butanol/water mixture were removed, 260 parts of n-butanol were added to the clear solution and the reaction temperature was lowered to 22 -25 C. The solution was neutralized with 10% caustic to a pH 9-10, followed by removal of more of a n-butanol/water mixture under reduced pres-sure~ The residue was filtered with a filter aid. The resulting water-white syrup had a Gardner-Holdt viscosity of Y-Z (25 C.). Pan solids were 95% (2 hours at 105 C.) and foil solids were 97% (45 minutes at 45 C.). The gel phase chromatography indicated that the product was 85% monomeric. The nuclear magnetic resonance (nmr) of the product confirmed the structure of the mononer to be tetrabutoxymethyl glycoluril.
Preparation of Tetrabutoxymethyl Glycoluril Into a suitable reaction vessel equipped with a stirrer, thermo-meter, and reflux condenser there was introduced 344 parts (5moles) of aqueous formaldehyde (44%) and the pH was adjusted to 7.5 with 6 parts of 0.5N NaOH
solution. To this solution, 142 parts of glycoluril (1 mole) were added and the reaction mixture was heated to 80 C. Two parts of 0.5N NaOH solution _~ _ i~SOS3 were added to adjust the pH to 7Ø In half an hour, the reaction mixture became a clear solution. It was then cooled to 25 C. and the pH was adjusted to 7.4 with three parts of 0.5N NaOH solution. The clear pale yellow colored solution was then distilled at 55 C. under reduced pressure to remove water.
After 150 parts of water were removed, 740 parts (10 moles) of n-butanol and 1 part of concentrated nitric acid were added to the resulting syrup. The mixture was heated to reflux with stirring. After about 10 minutes, the reaction mixture became clear and water white; the reflux temperature was 95-98 C. The water formed during the reaction was decanted by the use of a standard decant apparatus. In about three hours, 150 parts of decant liquid (water with 8% n-butanol) were collected. The reaction temperature after that period was 115 -116 C. When water stopped coming over by decant, the solution was cooled to 22 -24 C. and neutralized with 10 parts of 0.5N NaOH
solution. The excess butanol was removed at atmospheric pressure, and later under reduced pressure, and residual syrup was filtered in the presence of activiated charcoal and filter aid. The yield of the resulting syrup was 410 parts (approximately 87% yield). The other physical characteristics were as follows: Foil Solids: 96.4%; Pan Solids: 94.7%; Gardner-Holdt Viscosity (25 C.): P~Q; Gardner Color~ ]; Water Tolerance: 321.
Preparation of Partially Methylated Tetramethylol Glycoluril Into a suitable reaction vessel equipped with a stirrer, thermo-meter, and reflux condenser there was introduced 950 parts (30 moles) of methanol and 40 parts of concentrated hydrochloric acid. To this mixture, 262 parts (1 mole of tetramethylol glycoluril) were added and the reaction mixture was stirred at 25-30 C. In abou-t 15-20 minutes, all the tetramethylol _g _ '' ~O~OS3 glycoluril went into solution. After half an hour, the reaction mixture was neutralized with 140 parts of sodium bicarbonate and 20 parts of sodium car-bonate at 22 -23 C. The pH after neutralization was about 8. The salt was filtered. The filtrate was concentrated at 60 C. under reduced pressure.
The yield of the syrupy product after filtration of the salt was 290 parts, which was diluted to 90% solids with cellosolve. The product characteris-tics were as follows: Foil Solids: 91.4%; Pan Solids: 82.2%; and Gardner-Holdt Viscosith (25 C.): Z1 IR of the product indicated that the methylated product has a significant amount of unreacted methylol groups.
Preparation of Tetramethoxymethyl Glycoluril Into a suitable reaction vessel equipped with stirrer~ thermometer, and condenser were charged 640 parts (20 moles) of methanol and 20 parts of 70% c-on. nitric acid. To this acidic methanol, 262 parts (1 mole) of tetra-methylol glycoluril were charged, and the reaction mixture was heated to 40 C. with stirring. In about 20 minutes, all of the tetramethylol glycoluril went into solution. When the reaction mixture became clear, it was cooled to 22 C. and 45 parts of 20% sodium hydroxide solution were added to neutralize the reaction mixture to a pH of 7-8. The neutralized clear solution was heated to 50 -55 C. and 450 parts of methanol were removed under slightly reduced pressure. The residue in the flask crystallized on standing for a few hours. The crystalline solids were filtered and washed with a small amount of water. The filtrate was then vacuum stripped at 70 -80 C. to remove all the water. The solid residue was then dissolved in benzene and the undissolved salt was removed by filtration. The benzene solution was mixed with the first crop of solid crystals and dissolved with additional benzene and was filtered .

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~0~50~3 again. On removal of benzene, 310 parts of tetramethox~ ethyl glycoluril (TMMGU) was obtained. The yield was 97%. It was recrystallized from benzene.
The recrystallized product had the melting point of 116 -118 C. The structure of TMMW was confirmed by I.R., N.M.R. and nitrogen analysis.
Preparation of Dimethoxymethyl Diethoxymethyl Glycoluril Into a suitable reaction vessel equipped with stirrer, thermometer, and condenser, were charged 320 parts (10 moles) of methanol, 460 parts of ethanol (10 moles), and 20 parts of 70~ concentration of nitric acid. To this acidic alcoholic mixture, 262 parts (1 mole) of tetramethylol glycoluril were charged, and the reaction mixture was heated to 40 C. with stirring.
In about 20 minutes, all of the tetramethylol glycoluril went into solution.
When the reaction mixture became clear, it was cooled to 22 C. and 45 parts of 20% sodium hydroxide solution were added to neutralize the reaction mixture to pH 7-8. The neutralized clear solution was heated slowly to 105 C. under reduced pressure, to remove substantially all of the alcohol-water mixture.
The resultant syrup was filtered hot at 80 C. to remove the inorganic sa]t and other impurities. The yield of the syrupy dimethoxymethyl diethoxymethyl glycoluril was 320 gms. The structure of this product was confirmed by N.M.R. The Pan Solids were 95.0%, and Foil Solids were 98.5%. The Gardner-Holdt viscosity was Z3-Z4 (25 C.).
Among the glycoluril derivatives that may be used as the cross-linking agent in the compositions of Application Serial No. 268 635, are dimethylol glycoluril, trimethylol glycoluril, tetramethylol glycoluril, monomethylether of dimethylol glycoluril, the dimethylether of dimethylol glycoluril, the trimethylether of tetramethylol glycoluril, the tetramethyl-5~3 ether of tetramethylol glycoluril, tetrakisethoxymethyl glycoluril, tetrakis-propoxymethyl glycoluril, tetrakisbutoxymethyl glycoluril, tetrakisamyloxy-methyl glycoluril, tetrakishexoxymethyl glycoluril and the like. As examples of mixed ethers of glycolurilin accordance with this invention, mention is made of the diethyl, dimethylethers of tetramethylol glycoluril, the diethyl, dipropylethers of tetramethylol glycoluril, the dibutyl, diethylethers of tetramethylol glycoluril, the diethyl, dihexylethers of tetramethylol gly-coluril and the like. When water solubility is desired, it is preferred to make use of the lower alkoxy derivatives. On the other hand, when the use of colloidal dispersions of lacticiferous dispersions are to be used, the higher alkoxy derivatives can be used. If desired, these crosslinking agents may be used singly or in combination with one another although it is generally preferred to use these crosslinking agents singly. The amount of the gly-coluril derivatives used in the compositions of the present invention may be varied between about 2% and about 50%, by weight, based on the total solids weight of the glycoluril derivatives and the water-dispersible, non-gelled, non-self-crosslinking polymeric material. It is preferred to use the glycol-uril derivatives in the weight percent basis varying between about 10% and 40%, by weight, same basis. There obviously will then be present in the composition between about 50% and about 98%, by weight, of the non-self-crosslinking polymeric material and preferably between about 60% and 90%, by weight, of said polymeric material, same basis, wherein the percentages of the glycoluril derivative and the polymeric material, by weight, total 100% and are based on the total solids weight of the glycoluril derivative and the polymeric material.

~LO~JS053 The component (B) used in the composition is the organic solvent soluble or water-dispersible non-gelled, non-self-crosslinking polymeric material which contains certain reactive groups including any one or more of carboxyl groups, alcoholic hydroxyl groups or amide groups. The amount of said groups that is present in said polymeric material may be varied between about O.S%, by weight3 and not more than about 25%, by weight, based on the total weight of said polymeric material. For most technical purposes these reactive groups will be the sole reactive groups in the polymeric material.
Any one of these reactive groups may be present in the polymeric material to the exclusion of the other reactive groups or all three of these three reactive groups may be present in the polymeric material simultaneously.
These polymeric materials may be anionic or non-ionic. These polymeric materia~s may be any one of a plurality of vinyl polymers which may be pre-pared by polymerizing polymerizable monomers containing reactive carboxyl groups such as acrylic acid, methacrylic acid, crotonic acid, cinnamic acid, -benzoyl acrylic acid and polycarboxylic acids of the ~,~-ethylenically unsaturated class such as maleic, fumaric, itaconic, mesaconic, aconitic and the halogenated acids such as the halogenated maleic, or more specifically, chloromaleic acid and the like. These carboxylic groups containing monomers can be used either singly or in combination with one another in the required amount and may be used with other polymerizable monomers that contain reactive alcoholic hydroxy groups or the reactive amide groups or may be used with other monomers which contain no reactive groups other than the reactive ethylenic double bond including no carboxylic groups such as methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, octyl acrylate, decyl -13~

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acrylate, lauryl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, heptyl methacrylate, decyl methacrylate, propyl crotonate, butyl crotonate, nonyl crotonate and the like. These polymerizable monomers devoid of any reactive groups may be used singly or in combination with one another in copolymerizing with a monomer containing a reactive group of the class described. Still further, one could use such other polymerizable compounds containing no reactive groups such as styrene, o-, m-, or p-alkyl styrenes such as the o-, m-, or p-methyl, ethyl, propyl and butyl styrenes, 2,4-dimethyl styrene, 2,3-dimethyl styrene, 2,5--dimethyl styrene, vinyl naphtha-lene, methyl vinyl ether, n-butyl vinyl ether, phenyl vinyl ether, acryloni-trile, methacrylonitrile, halo ring or side chain styrenes such as ~-chloro styrene, o-, m-, or p-chloro styrene, 2,4-dichlorostyrene, 2,3-dichlorostyr-ene, 2,5-dichlorostyrene or the alkyl side chain styrenes such as the - q methylstyrene,~-ethylstyrene and the like.
If one wishes to prepare a polymeric material as component (B), utilizing a polymerizable monomer containing a reactive alcoholic group, one may use such polymerizablevinyl monomers as the hydroxyl alkyl esters of the a,JB unsaturated monocarboxylic acids such as the hydroxy alkyl esters of acrylic acid, methacrylic acid, ethacrylic and the chloro as well as the other chloro substituted acrylic acids. These esters may either have a pri-mary or a secondary hydroxyl group. Illustrative of the types of compounds that can be used to make the polymers containing the reactive alcoholic hydroxy groups are 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 3-hydroxypropyl acrylate, 2-hydroxybutyl acrylate, 3-hydroxybutyl acrylate, 4-hydroxybutyl acrylate, 8-hydroxyoctyl acrylate~ 2-hydroxyethyl methacrylate, ~50S3 5-hydroxyhexyl methacrylate, 6-hydroxyoctyl methacrylate, 8-hydroxyoctyl methacrylate, 10-hydroxydecyl methacrylate, 3-hydroxypropyl crotonate, 4-hydroxyamyl crotonate, 5-hydroxyamyl crotonate, 6-hydroxyhexyl crotonate, 7-hydroxyheptyl crotonate, 10-hydroxydecyl crotonate, and the like. These hydroxy esters may be used either singly or in combination with one another or with the polymerizable vinyl monomers devoid of any reactive group includ-ing those set forth hereinabove in the discussion of the carboxyl group containing monomers. Obviously, these hydroxy ester monomers may be used in combination with the reactive carboxyl group-containing monomers set forth hereinabove.
Among the amide group-containing monomers which may be used to prepare the polymeric material identified as component (B) are acrylamide, methacrylamide, ethacrylamide and the like. These polymerizable acrylamides may be used to prepare the polymeric materials usad with any of the carboxyl group-containing monomers and/or the hydroxyl group-containing monomers or with any of the polymerizab]e monomers set forth hereinabove that are devoid of any reactive groups. These polymeric materials whether they contain the reactive carboxyl groups and/or the reactive alcoholic hydroxy groups and/or the reactive amide groups will be anionic polymeric materials.
Additionally, one can make use of polyester resin compositions which are organic solvent dispersible, non-gelled, polymeric materials. Or-ganic solvent dispersible alkyd resins, whether oil free or glyceride oil-con-taining, may be used and a plurality of these materials are commercially avail-able and are also well known in the art and, as a consequence, it is not deemed : , 1095(:~S3 necessary to make any prolonged recitation of such materials since they are fundamentally prepared by reacting a polyhydric alcohol with a polycarboxylic acid or with anhydrides such as phthalic anhydride,maleic anhydride, and the like.
Additionally, one can make use of polyester resin compositions which are water-dispersible, non-gelled, anionic polymeric materials. Water-soluble alkyd resins or water-dispersible alkyd resins, whether oil free or glyceride oil-containing, may be used and a plurality of these materials are commercially available and are also well known in the art and, as a conse-quence, it is not deemed necessary to make any prolonged recitation of such materials since they are fundamentally prepared by reacting a polyhydric alcohol with a polycarboxylic acid or with anhydrides such as phthalic an-hydride, maleic anhydride, and the like.
Additionally, one can use certain polyether polyols such as those prepared by reacting one mole of bis-phenol A and/or hydrogenated bis-phenol A with at least two moles of ethylene oxide and/or propylene oxide.
The following examples are illustrative of the various kinds of organic solvent soluble, non-gelled, non-self-crosslinking polymeric materials which can be used in the composition of the present invention.
Polyester Resin A
This oil free saturated polyester resin is commercially available and is prepared by reacting isophthalic acid, adipic acid and propylene glycol in a conventional esterification process. This polyester resin is identified as a saturated polyester resin inasmuch as it is free of non-benzenoid un-saturation. The polyester, designed for coil coating, has the following .
- -~: ~ . - : . . .

~0~5053 characteristics: Solids 70% in Solvesso 150, a high boiling hydrocarbon solvent; Gardner-Holdt viscosity (25 C.) Zl-z3; acid number 10 maximum;
hydroxy number 30.
Resin B
Resin B is a polyether polyol, that is available commercially.
Resin B is prepared by reacting one mole of bis-phenol A with four moles of ethylene oxide. This polyether polyol has a hydroxyl number of about 260-270.
Acrylic Resin C
Acrylic resin C is a commercially available anionic acrylic polymer prepared by the standard polymerization techniques in an inert organic sol-vent such as 2-ethoxyethanol in which 55 parts of n-butylacrylate, 30 parts of styrene, and 15 parts of acrylic acid are copolymerized. At the end of the polymerization, the resulting polymer is diluted to 75% solids with n-butanol. The average molecular weight of the polymeric material is about 10,000-20,000 and has an acid number of 11~. This polymer is designed for water-based coatings and electrocoatings. At 75% solids and 25 C., it has a Gardner-Holdt viscosity of Z6+
Resin D
Into a suitable reaction vessel equipped with a stirrer, thermometer, inert gas-inlet and outlet tubes and partial condenser, there was introduced 668 parts of neopentyl glycol, 96 parts of trimethylol propane, 509 parts of isophthalic acid and ~8 parts of adipic acid. These reactants were heated under a blanket of nitrogen gas to a temperature of 230 C , while the water of esterification was continuously removed with constant agitation. After 7 ' '~ -~o~s~s~

hours, the acid number of the reaction mass was 9. The reaction mass was cooled to 150 C. and diluted to 90~ solids with a 1:1 mixture of n-butyl acetate and cellosolve acetate The final product had the Gardner-Holdt viscosity of Z6+ at 90% solids. The resin had a hydroxyl number of 88 and an acid number of 9.
The following examples are illustrative of the various kinds of water-dispersible, non-gelled, non-self-crosslinking polymeric materials which can be used.
Polyester Resin E
Into a suitable reaction vessel equipped with an agitator, thermo meter, inert gas-inlet tube and partial condenser, there was introduced 866 parts of neopentyl glycol, 56 parts of trimethylol propane, 74 parts of di-methylol propionic acid, 303 parts of adipic acid and 240 parts of a mixture of oligomers containing about 70% of trimer acid and about 13% of dimer acid and 17% of monomer acid, by weight, wherein said oligomers are derived from tall oil fatty acids which are primarily oleic and linoleic acids, 74 parts of dipropylene glycol and 1087 parts of isophthalic acid. These reactants were heated under a blanket of nitrogen at a temperature of about 165 to 190 C. while the water of esterification was continuously removed with con-20 stant agitation. The heating was then increased and the temperature slowly rose to about 230 C. as the isophthalic acid reacted. When the reaction mass was clear, the acid number was about 20-25, the temperature was quickly lowered to about 190 C. and 64 grams of trimellitic anhydride were added.
After holding the reaction mass for an additional 30 minutes at 185 C., the acid number was 44. The resin was cut to a 75% resin solids content using a :: .

S(:)S3 mixture of n-butanol and 2-butoxy ethanol. The cut resin solution had a viscosity of Z6 ~ Z7 on the Gardner-Holdt scale at 25 C.
Acrylic Emulsion F
Acrylic emulsion F is a commercially available acrylic emulsion polymer prepared by polymeri7ing a monomer blend of 55 parts of n-butyl-acrylate, 30 parts of styrene, and 15 parts of acrylic acid. The emulsion has an acid number of 90-100 on a solids basis and a final solids content of about 48%.
Acrylic Emulsion G
Acrylic emulsion G was prepared by a standard aqueous emulsion polymerization technique using the monomer blend of 45 parts of n-butyl acrylate, 32 parts of methyl methacrylate, 21 parts of acrylonitrile, and

2 parts of methacrylic acid. For the emulsion polymerization, 0.42 part of ammonium persulfate and 2 parts of an alkyl sulfosuccinate were used as an initiator and as a surfactant, respectively. The emulsion polymerization was carried out at 80 C. The final product had a solids content of 50%
and had an acid number of 13.
Acrylic Emulsion H
..;, Acrylic emulsion H was prepared by a procedure very similar to that used in preparing the acrylic emulsion G. In this polymerization, the monomer composition was a blend of 45 parts of n-buty] acrylate, 28 parts of methyl methacrylate, 19 parts of acrylonitrile, 3 parts of methacrylic acid and 5 parts of 2-hydroxyethyl acrylate. The final product had a solids content of 43% and an acid number of 19, as well as a hydroxyl number of 24.

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10~51~53 Polyether Polyol I
Polyether polyol I was prepared by reacting one mole of bis-phenol A (4,4' isopropylidene diphenol) with 6 Inoles of ethylene oxide. The result-ing product had a viscosity of 2~40 centipoises and a hydroxyl number of 215.
The molecular weight of the polyether polyol I was about 520. Polyether polyol I was a liquid material.
The third essential component (component C) used is an acid catalyst. This catalyst is used in an amount varying between about 0.05% to about 5.0%, by weight, based on the total solids weight of (A) and (B). It is preferred to use between about 0.1% and 2.5%, by weight, of the acid catalyst, same basis. Among the preferred acid catalysts that may be used are: tris-methyl sulfonylmethane, trishexyl sulfonylmethane, p-toluene sulfonic acid, n-dodecyl benzene sulfonic acid, naphthalene sulfonic acid, dinonyl naphtha-lene disulfonic acid and the like. The catalytic activity of an acid can also be generated in the coating compositions by incorporating sulfonic acid groups into the polymeric material (B). This can be achieved by copolymerizing from about 0.1% to about 5.0% (based on the total monomer weight) of a monomer such as 2-sulfoethyl methacrylate, styrene sulfonic acid and the like. It is also possible to use alkyl esters of phosphoric acid or alkylphosphonic acids as the acid catalyst in the coating compositions.
Weaker organic acids, such as formic acid, acetic acid, phthalic acid and the like may be used but are not preferred because they are not effective in promoting the crosslinking reaction at temperatures below 175C
in a reasonable period of time such as less than about 30 minutes.
Inorganic acids such as nitric, sulfuric, phosphoric, hydrohalic, JlO95~S3 Lewis acids and the like may also be used.
In order that the concept of both the parent application Serial No.
268 635 and the present invention may be more completely understood, the following examples are set forth in which all parts are parts by weight unless otherwise indicated. ~hese examples are set forth primarily for the purpose of illustration.
Examples 1 and 2 and Comparative Example 3 Three paint formulations, shown hereinbelow in Table 1, were pre-pared utilizing the oil-free saturated polyester resin A and a crosslinking agent which, in the first and second examples, was the ~e~rabutoxymethyl glycoluril (TBMGU) and in the third comparative example, the crosslinking agent was hexakismethoxymethylmelamine (HMMM). In Examples 1 and 2, the resin-crosslinking agent ratios were 76/24 and 83/17 respectively. In the comparative Example 3, the resin-crosslinking agent (HMMM) ratio was 90/10.
It had been determined from experience that the best film propertics were obtained at this level of HMMM content and when the cure temperature of 230 C. was used for 60 seconds. These organo-soluble enamels were prepared by using a three roll mill. The enamels, thus prepared, were drawn down on Alodine 1200S treated aluminum panels using a 0.002" drawblade. Some of the films were cured at 230 C for 60 seconds and others were cured at 260 C
for 60 seconds. In Table II, set forth hereinbelow, there is shown the film properties obtained from the three formulations. Table II shows that the enamels prepared from TBM W are superior in performance over that prepared from HMMM in the following respects: (a) shows no impact frilling either 3 on overbake or exposure to humidity; (b) superior humidity resistance; (c) 1(~95053 better fabrication properties as shown by a good T-0 bend. The enamels based on the TBMGU show good oven bake ~;loss retention and superior accelerated weathering tests.
TABIE I
Comparative ExampleExampleExample Titanium dioxide Pigment 119.3 119.3 119.3 Saturated Polyester Resin A 56.9 56.9 68 Saturated Polyester Resin A105.4 84.0 119.5 TBMGU (97.5%) 37.1 23.0 --Cellosolve acetate 18.9 18.9 18.9 14.3 Sili cone L 5310 resin 0.15 0.15 0.15 Isophorone 2.5 6.8 2.6 Diacetone alcohol 2.5 4.8 1].. 3 Butyl Cellosolve 3.0 3.0 3.0 Solvesso 150 34.5 64.:1. 20.0 N-Butanol 16.9 17.1 13.0 p-Toluene sulfon.ic acid 0.3 0.3 0.3 Pigment/Binder 80/100 90/100 80/100 Resin/Crosslinker 76/24 83/17 90/10 .
.

TABLE II
_ .
ENA~EL PROPERTIES
Comparative Example Example Example Polyester Resin A/CLA 76/24 83/17 90/10 Crosslinking agent (CLA) TBMGU TBMGU HMMM
Cure cycle, 60", seconds 230C 260C 230C 260C 230C
Film thickness, mils0.8 0.8 0.8 0.8 1.0 Gloss, 60 -- 95 94 92 97 Gloss, 20 -- 87 80 82 89 Knoop hardness(KH N2 ) 3.8 7.4 5.0 9.2 6.2 Impact, reverse, in ~bs. 70 70 70 70 70 Fabrication potential, T- .~
bend passes T-O T-O T-O T-2 T-O
to T-l Adhesion, cross hatched and taped 100 100 100 100 100 MEK Resistance, double rubs 200 + 200 + 200 +200 + 200 +
Oven bake 60"
Gloss, 20 % retention 100 98 100 100 100 Impact frilling, none on impact bump 60 60 70 50 70 T-bend, no popping on bend T-2 T-2 T-O T-2 T-l to T-2 .;;
Cure cycle, 60" seconds 260C 230C 260C
Effect of Cleveland Humidity test (60C) on -- --the impacted enamel (10 to 70 in. lbs.) -- 70 70 70 Initial impact resistance, reverse, passes -- 70 70 70 After 1 hour -- 70 70 40 After 24 hours -- 70 70 40 After 4 days -- 70 70 40 After 8 days -- 70 70 40 After 18 days -- 70 70 40 Blister freeBlister free Badly surface free blistered surfaceenamel surface Cure Cycle 60 Seconds 230C 260C 230C
Accelerated Weathering Test (XENON ARC) Initial Gloss 60 95 95 95 Initial Gloss 20 82 87 86 After 1,000 Hours Gloss 60 89 89 79 Gloss 20 62 62 47 .
, : , -, Example 4 A high solids organic solvent based enamel was prepared using poly-ether polyol B and acrylic resin C in combination with tetrabutoxymethyl glycoluril (TBMGU). 33 Parts of polyether polyol B, 34 parts of acrylic resin C and 33 parts of the tetrabutoxymethyl glycoluril were blended together in a suitable blending mill. To this blend is added 0.5 part of n-dodecylbenzine sulfonic acid, 1.0 part of dimethylaminoethanol and 90 parts of titanium dioxide pigment. The pigment was dispersed in the blend using a Cowless dissolver. The dispersed pigment paste was diluted to 75% solids with cello-solve. At 75% paint solids the Ford cup #4 viscosity was about 60 seconds.
The enamel was sprayed on iron phosphate pretreafed cold rolled steel panels and cured at 150C. for 20 minutes. The cured films had the following pro-perties:
Film thickness 1.0 mil Pencil hardness H-2H
Knoop hardness (KHN25) 12.0 Gloss 60 77 Initial impact Resistance, 60 in. lbs. (Reverse) Impact popping after exposuOre to Cleveland Humidity Test (60 C. on the impacted enamel) After one hour, in. lbs. 60 After two hours, in. lbs. 50 After 24 hours, in. lbs~ 50 The enamel, after storage at 55 C. for three weeks, was stable.

` ~ :

~0~0~3 Fxample _ Into a three roll mill there is introduced 332 parts of titanium dioxide pigment which was dispersed with 233 parts of the acrylic resin C.
To this pigment paste, 133 parts of the acrylic resin C, 92 parts of the tetrabutoxymethyl glycoluril ~TBMGU), 194 parts of xylene, 23 parts of cello-solve acetate, 23 parts of n-~utanol, and 8 parts of p-toluene sulfonic acid disso]ved in 12 parts of isopropanol were charged and mixed thoroughly on a mechanical shaker. me resulting organo-soluble paint had a Ford cup #4 viscosity of 62 seconds at 25 C. The paint solids were 68%. Films were drawn down on zinc phosphate pretreated cold rolled steel, using a 0.002"
drawblade, and these coated panels were cured at 175 C. for 20 ~inutes. me film properties were as follows:
Film thickness 1.0 mil Gloss 60 76 Gloss 20 50 Pencil Hardness F-H
Knoop Hardness 6.0 Reverse impact resistance, 50-50 in. lbs.
MEK resistance (Double rubs) ~ 200 Humidity resistance ~Cleveland No change in gloss Humidity Chamber, 60 C.) after 10 days Salt spray resistance 240 hrs.
(ASTM #B117-64) Creepage along the scribe less than 1/32' line Blisters None 10950~3 Example 6 Into a three roll mill there is introduced 346 parts of titanium dioxide pi~nent and 210 parts of polyester resin D and 10 parts of cellosolve acetate and the three components were dispersed together to form a pigment paste. To this pigment paste there is charged 103 parts of the polyester resin D, 115 parts of tetrabutoxymethyl glycoluril (~MBGU), 3.1 parts of dinonyl naphthalene disulfonic acid, 117 parts of n-butanol and 88 parts of butylacetate. The charge was mixed thoroughly on a mechanical shaker. The resulting paint had a Ford cup #4 viscosity of 60 seconds at 25 C. The 10 paint solids were 73%. Films were drawn down on zinc phosphate pretreated cold rolled steel panels, using a 0.002" drawblade and the panels were baked so as to cure the coatings at 175 C. for 20 minutes. The film properties were as follows:
Film thickness 1.0 mil Gloss 60 86 Gloss 20 52 Pencil hardness 2H-3H
Knoop hardness 11.4 Reverse Impact resistance, in. 140+
lbs.
MEK resistance (Double rubs) ~ 200 Humidity resistance ~Cleveland No change in gloss HwrLidity chamber, 60 C.) after 10 days Salt spray resistance 240 hrs.
(ASI~ #B 117-64) Creepage along the scribe less than 1/32"
line Blisters None : ., ,. ~ :

~ILO~S053 Exam~le 7 ~ ~ ve Example 8 Paint form-llations shown in Table III hereinbelow were prepared utilizing Acrylic resin C and a crosslinking agent which, in the first instance, was the tetrabutoxymethyl glycoluril tTBMGU) and in the second instance was hexakismethoxymethyl melamine (HMMM~. In both formulations the resin-crosslinking agent ratios were identical. The amounts and kinds of ingredients used in the formulations were as shown in Table III. These water-based enamels were prepared by using a three roll mill and a Cowles dissolver. The enamels thus prepared were drawn down on zinc phosphate pretreated cold rolled steel using 0.003 inch drawblade. The films were cured at 175 C. for 20 minutes. Table III shows the film properties obtained from the two formulations. The films based on the TBMGU have higher reverse impact of 30-40 inch-potmds against 10-20 inch-pounds for the films based on the HMMM. The humidity and salt spray resistance are far superior in the case of TBMGU, as shown in Table III. For instance, after 500 hours of the salt spray test (ASTM Specification No. B-117-64) on the film based on TBMW
had no blisters and no creepage at the scribe line.

~O~S3 TABLE III
COMPARATIVE

Titanium dioxide pigment 186.5 ~~~~ 186.'5 Acrylic Resin A (75% solids) 124.2 124.2 Dimeth~l amino ethanol 9.7 9-7 Dispersed the mixture on a three roll mill and added:
Acrylic Resin C(75%) 124.3 124.3 TBMGU (97%) 48 --HMMM -- 46.7 Dimethylamino ethanol 9.8 9.8 p-toluenesulfonic acid 0.45 0.45 Water,'deionized 495 496.5 Pigment/Binder 80/100 80/100 Resin/Crosslinker 80/20 80/20 Paint Solids 42 42 Film Properties Cure Cycle, 20 min. at 175C.
Film thickne'ss, mil ' ' 0.8 0.8 Gloss, 60 90 89 Gloss, 20 69 71 Knoop hardness (KHN ) 7.6 10.7 Impact resistance, reverse, in lbs. 30-40 10-20 MEK Resistance, double rubs 200+ 200+
Salt spray resistance (ASTM #B117-64~ * **
240 hrs.
500 hrs. * ~~~
Cleveland Humidity:
Resistance (C1~eveland Humidity Chamber, 60C) Initial Gloss 20 78 80 % Gloss retention after 3 days 96*** 99***
% Gloss retention after 5 days 96*** 99***
% Gloss retention after ll days 87 few 87 few scattered scattered blisters blisters % Gloss retention after 18 days 74 few to 26****
medium blisters * no creepage along the scribeline-no blisters **2-3 mm creepage along the scribeline-no blisters ***no blisters ****blisters very dense :

~109~50~ii3 Example 9 204 Parts of titanium dioxide pigment were dispersed in 164 parts of Polyester resin E, and 5 parts of Acrylic resin C~ and 8 parts of dimethyl-amino ethanol, using a three roll mill. To this pigment grind, 109 parts of Polyester E, 50 parts of TB~GU, 0.5 part of p-toluene sulfonic acid, and 7 parts of dimethylamino ethanol were added and blended using a high speed disperser~ followed by the addition of 441 parts of deionized water. The resultant water-borne enamel had Ford cup #4 viscosity of 60 seconds at about ~-46~ solids.
The enamel thus prepared was drawn down on iron phosphate pretreated cold rolled steel using 0.003" drawblade. The films were cured at 175 C. for 20 minutes. The filmpr~perties were as follows:
The cured films had a thickness of 1.0 mil. mey were hard and resistant to organic solvents such as acetone, methyl ethyl ketone, etc. The film properties were as follows: 60 gloss: 96; Knoop hardness: 6.2;
re~erse impact: 120 kn.-lbs. After 240 hours salt spray exposure, there were no blisters on the films and very little creepage on the scr~e line. The humidity resistance (Cleveland humidity chamber, 60 C.) after 2 weeks was excellent. There were no blisters on the film or any loss of gloss. Over-bake stability of the film was excellent.
Examples 10, 11 and 12 Paint form~lations shown in Table IV were prepared utilizing Acrylic resin C and the crosslinking agent tetramethoxymethyl glycoluril (TMMGU). Three formulations were prepared at the resin/crosslinking agent (TMMW ) ratios of 75/25, 70/30, and 65/35 respectively on a solids basis.

109Sl~S3 In all the formulations, the pigment-binder ratio was 80/100, and dimethyl aminoethanol was used to neutralize 60% of the available carboxylic groups of the acrylic resin. p-Toluene sulfonic acid was used as the catalyst. The water-based enamels were prepared by using a three roll mill by a procedure, similar to that described in Example 7. The final paint solids and the viscosity of these enamels are shown in Table IV. The enamels ~hus prepared were drawn down on zinc phosphate pretreated cold rolled steel using 0.003"
drawblade. The films were cured at 175 C. for 20 minutes. Table IV shows the film properties and Table IV continued shows the results of salt spray resistance with the variations in the level of crosslinking agent content (TMMGU). Table IV shows excellent film properties. The best corrosion resistance of the film was obtained at the resin crosslinker ratios of ?5/25 and 70/30 respectively.

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Example 13 Paint Formulation 245 Parts of the Acrylic emulsion F, 95 parts of deionized water, 103 parts of dimethoxymethyl diethoxymethyl glycoluril, 308 parts of titanium -~-dioxide pigment, and 4.1 parts of dimethylamine ethanol were sand milled.
After the pigment was properly dispersed, an additional 245 parts of the Acrylic emulsion F, were slowly added, -followed by 0.72 part of p-toluene sulfonic acid dissolved in 1 part of isopropanol~ 4.1 parts of dimethylamino ethanol, and 45 parts of deionized water. The resultant water-based enamel had the Ford cup #4 viscosity of 50 seconds at 25C. at a solids content of 61%. The films were drawn down on zinc phosphate pretreated cold rolled steel, using 0.002" drawblade, and they were cured at 175 C. for 20 minutes.
The film properties were as follows:
Film thickness 1.0 mil Gloss 60 92 Gloss 20 79 Knoop hardness 14.4 Pencil hardness H-2H

Re~erse impact resistance, in.
lbs. 0-10 MEK resistance (Double rubs) ~ 200 The water-based enamel, after aging at 55 C. for 21 days, had excellent stability. There was no pigment settlement and there was no change in the film properties of the coatings prepared from the aged enamel.
Example 14 A clear water-borne ~arnish was prepared by blending on a high speed -~0~3~0S3 stirrer 60 parts of the Acrylic emulsion G, 3.3 parts of tetramethox~nethyl glycoluril, 1.2 parts of dimethyl ~nino ethanol, 0.06 part of p-toluene sulfonic acid dissolved in the same amount of isopropanol, and 10 parts of deionized water. The resultant varnish was drawn down on aluminum panels (alodine 1200S treatment) and separately on iron phosphate treated cold rolled - steel panels, using a No. 22 wire cator. The films were cured at 150 C. for 20 minutes, and at 260 C. for 60 seconds or 90 seconds. The fi~n properties were as follows:
Substrate: Alodine 1200S
Cure conditions 150 C/20 min. 260 C./60 sec Film Thickness 0.65 mil 0.6 mil Knoop Hardness 6.9 7-4 Pencil Hardness H-2H H-2H

MEK resistance ~ 200 > 200 (Double rub) Reverse impact ~ 60 > 60 resistance in,lbs.
Substrate: Zinc phosphate treated cold rolled steel Cure conditions 150 C./20 min. 260 C/90 sec Fi~n Thickness 0.75 mil 0.8 mil Knoop Hardness 6-8 6-8 Pencil Hardness H-2H H-2H

MEK resistance 90 ~ 200 (Double rub) Example 15 A clear water-borne varnish was prepared by blending 67 parts of the acrylic emulsion H, 10 parts of tetramethylol glycoluril dissolved in 5 parts of water and 0.21 part of 50% aqueous solution of p-toluene sulfonic acid. The initial viscosity of the varnish was 15 cps. and had a pH of - 34 _ .
'-, .

5 [)~S3 4.75. The varnish was drawn down on aluminum (alodine 1200S treatment), using a No. 34 wire cator. The films were cured at 125 C. for 20 minutes and 260 C. for 1 minute. The film properties were as follows:

Cure Condition 125 C./20 min. 260 C/l min.
Film Thickness 1.0 mil 1.0 mil Knoop Hardness 3.3 4.8 MEK Resistance 200 200 (Double rubs) A comparable varnish film of 1.0 mil, prepared without any tetra-methylol glycoluril, and cured at 125 C. for 20 minutes had knoop hardness of 2.3, and MEK resistance of less than 9 rubs~ The varnish containing tetramethylol glycoluril was aged for 3 weeks at 55 C. after which there was no coagulation or phase separation in the varnish. The brookfield viscosity was unchanged, and the pH was 3.45. The aged varnish cured as well as the initial formulation.
Example 16 60 Parts of Polyether polyol I, 40 parts of dimethoxymethyl di-ethoxymethyl glycoluril, and 90 parts of titanium dioxide were dispersed in a high speed Cowles dissolver. To this dispersed pigmented paste were added 1.2 parts of p-toluene sulfonic acid, dissolved in 1.8 parts of iso-propanol and blended together on a high speed stirrer, followed by the addi-tion of 17 parts of deionized water. The resultant water-based high solids enamel had the Ford cup #4 viscosity of 60 seconds at 25 C The films were drawn down with a 0.003" draw down blade on zinc phosphate pretreated cold rolled steel panels and were cured at 125 C. for 20 minutes. The film properties were as follows:

~10~0~3 Film thickness 1.1 mil.
Gloss 60 94 Gloss 20 79 Knoop Hardness ~25 g.) 11.7 Pencil HardnessH-2H

Revere Impact Re- 100-120 sistance ~in. lbs.) MEK resistance~ 200 ~double rubs) The water-based high solids enamel had good shelf stability. There were no significant changes in the film properties of the coating prepared from the enamel after aging for two weeks at 55C.
The compositions can also find utility in the field of electrodeposit-ions when used in the presence of an acid catalyst. The following example is illustrative of a paint formulation which is useful in electrocoating.

Into a high speed disperser there was introduced 77 parts of Acrylic resin C ~75% solids), 22 parts of TBMGU, 11.5 parts of diisopropanol amine, (50% solution) and 22 parts of titanium dioxide pigment. These materials were dispersed together in the high speed disperser and the dispersed pigment paste was diluted by slow addition of deionized water to the extent of 1,000 parts so as to make up a paint solids solution of 10%. To the 10% aqueous paint, there was added 0.5 part of dinonyl naphthalene disulfonic acid, preneu-tralized with diisopropanol amine. The 10% aqueous paint had a pH of 8.2 and conductivity of 780 j ohm lcm 1. The paint was aged overnight with con-stant stirring at ambient temperature. Zinc phosphate pretreated cold rolled steel panels were electrocoated at 150 volts for 60 seconds. The electrocoated steel panel was rinsed with deionized water and then cured at 175C. for 20 minutes. The cured film was 0.8 mil thick. It was resistant to methylethyl ketone rubs and other organic solvents. The Knoop hardness was 7.4 (KHN25) ~o~os3 ,~

and reverse impact resistance was 20-30 inch-pounds. The enamel, when ex-posed to salt spray resistance tests for 240 hours, had 2-3 mm. creepage at the scribe lines and no blisters on the surface.
In the compositions the component ~) is identified as an organic solvent soluble or a water-dispersible, non-gelled, non-self-crosslinking polymeric material which polymeric material contains as reactive groups any one or more of carboxyl groups, alcoholic hydroxyl groups or amide gro~ps wherein the amount of said groups is at least abou~ 0.5%, by weight, and not more than about 25%, by weight, based on the total weight of said polymeric material. The British Patent 1~146J858 and its French counterpart, 1~486,213 ~Florus et aL), disclose the use of certain glycoluril derivatives in combina-tion with self-crosslinking polymeric materials. The component (B) of said Florus et al. patents is a copolymer which may contain from 10 to 70 parts, by weight, of polymerized units of an ester of acrylic acid and/or methacrylic acid with a monohydric alcohol having from one to twenty carbon atoms and from 2 to 15 parts, by weight, of polymerized units of an ~ ethylenically unsatur-ated carboxylic acid containing from 3 to 6 carbon atoms and from 0 to 85 parts by weigh~ of polymerized units of at least one other ethylenically un-saturated comonomer. These patents teach that their copolymers may contain N-methylolacrylamide and/or N-methylolmethacrylamide and also the ethers of these amides with monohydric alcohols having from one to ten, and preferably

3 to 4, carbon atoms in amounts between about 0.5 to 40 and particularly 5 to 20 parts by weight. When these copolymers contain either the methylol acrylamides or the alkyl ethers of these methylol acrylamides, the copolymers are self-crosslinking. These polymeric materials of these foreign patents will self-crosslink under normal cure conditions of about 150 to 175C. in a period of from 20 to about 60 minutes. The tetrabutyoxymethyl glycoluril in the coating compositions of the Florus et al. patents does not function as a cross-.~
- ~ . - , : :

~0~50S3 linking agent with the polymeric materiai at the cure temperature of 150C.
rf anything, it only plasticizes the film and it does not function as an effective crosslinker but only as an additive to improve corrosion resistance.
The compositions of the present invention, on the other hand, contain a water-dispersible polymeric material which is not self-crosslinking but does contain -COOH, -OH and/or -CONH2 as the sole reactive groups and these groups do not self-condense at the practical cure conditions of 150 to 175C. in a period of 20 to 60 minutes. In order to achieve efficient crosslinking reaction of the glycoluril derivatives with a non-self-crosslink-ing polymeric material of the class used in the compositions of the presentinvention requires the presence of an acid catalyst. The French and British patents cited above do not disclose, teach or suggest the use of any acid catalyst in their compositions.
In order to illustrate differences from the compositions of the Florus et al. patents two acrylic resins were prepared namely Acrylic resin J and Acrylic resin K, which were substantially identical in composition except that the Acrylic resin J contained 125 parts of isobutoxymethylacryl-amide whereas the Acrylic resin K was devoid of any isobutoxymethylacrylamide.
Otherwise, the formulations were identical. The monomer composition in each of these Acrylic resin Eormulations is set forth hereinbelow.
Monomer Composition:
Resin J ~Parts) Resin K ~Parts~
2-Ethyl hexyl acrylate120 120 Acrylic acid 25 25 Isobutoxymethylacrylamide 125 ---2-hydroxyethylacrylate30 30 Styrene 200 200 These acrylic resins J and K were prepared separately in reaction . ~:

~10~iO53 vessels equipped with a stirrer, reflux condenser and a nitrogen inlet tube.
The Acrylic resin J had a monomer composition similar to those described in the French patent 1,~86,213 with these minor inconsequential differences. In-stead of the N-butoxymethylacrylamide and the 4-hydroxybutylacrylate there was substituted isobutoxymethylacrylamide and 2-hydroxyethylacrylate respec-tively. The Acrylic resin K had the identical monomer composition as that of the Acrylic resin J except there was present no isobutoxymethylacrylmide. The general procedure of the resin preparations is as follows: To the suitably equipped reaction vessel there is charged 200 parts of isobutanol and heated to 100-105C. To the heated solvent, there is added the monomer blend containing about 2%, by weight, based on the total monomer weight, of t-butyl perbenzoate and 2% by weight based on the total monomer weight, of n-dodecyl-mercaptan. These additives are charged into the reaction vessel over a period of two hours while maintaining the temperature of the solvent at about 100-105C. After the monomer addition has been completed, the reaction temperature is held at about 105C. for one hour. One part of additional t-butyl per-benzoate is added and the reaction is maintained at 105C. for one more hour. Later the resinsyrup in each instance is cooled and adjusted to 65%
solids with isobutanol.
Four coating formulations were prepared from each of these acrylic resin polymeric materials by blending the resins J and K separately with or without TB~GU and p-toluene sulfonic acid in the amounts shown in Table V
set forth hereinbelow. The fi].ms drawn down were about one mil thick and were drawn down on ~inc phosphate pretreated cold rolled steel panels. A
total of twenty-four panels were prepared. These panels were baked at 150C.
for 30 minutes, 150C for 60 minutes and 175C. for 20 minutes. The film properties on these panels are shown in Table VI.

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10~5053 In water-dispersible or water-dispersed coating compositions, if the polymeric material contains carboxylic acid groups, it is essential to use ammonia or a water-soluble organic amine in the composition in order to achieve the water-dispersibility of the total composition. The amount of ammonia or of the organic amine required is dictated by the amount of carboxylic acid groups present in the polymer. Normally, equivalent amounts of amine with respect to the carboxylic groups are sufficient to achieve water-dispersibility of the polymer and the coating composition. It is also possible to use only 10% to 20% of the equivalent amounts of amine with re-spect to the carboxylic acid groups of polymer, to achieve a water-dispersible composition. One can use ammonia or the water-soluble low molecular weight organic amines such as the primary, secondary or tertiary amines such as, for example, ethylamine, diethylamine, triethylamine, diethanolamine, N-N-dimethylethanolamine, diisopropanolamine and the like.
Although not required, in certain cases it may be helpful to make use of anionic or non-ionic surfactants to obtain stable water dispersions of these organic coating compositions The anionic surfactants, for example, can be sulfosuccinate, sodium dioctylsuccinate, sodium cyclohexylsuccinate and the like. A number of these anionic surfactants are available commercial-ly. The non-ionic surfactants can be ethoxylated alkyl phenol and the like.
The amount of the surfactant that is normally used is less than about 4%, by weight, based on the total paint solids weight.
Although the coatings will principally be used to coat metals such as steel, aluminum and the like, these coatings can also be used on other substrates such as wood, glass, plastics, paper, textiles and the like.

~: ~ : . :
:, : ~ -

Claims (10)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A coating composition comprising a mixture of from about 2% to about 50% by weight of (A) a glycoluril derivative having the following structural formula:

wherein n is an integer from 1 to 3 inclusive; R and R4 are individually dif-ferent alkyl radicals having from 1 to 6 carbon atoms inclusive; R2 and R3 are separately hydrogen or an alkyl radical having from 1 to 6 carbon atoms inclusive or a phenyl radical; and correspondingly from about 98% to about 50% by weight, of (B) a water dispersible, normally non-self-crosslinking polymeric material having as reactive groups, any one or more of carboxyl groups, alcoholic hydroxyl groups or amide groups wherein the amount of said groups is at least about 0.5% by weight, and not more than about 25%, by weight, based on the total weight of said polymeric material; and (C) from about 0.05% to 5.0%, by weight, of an acid catalyst based on the total weight of (A) and (B), wherein said reactive groups of (B) are heat reactive with (A) and wherein said percentages of (A) and (B), by weight, total 100% and are based on the total solids weight of (A) and (B).

2. An organic solvent soluble composition comprising a blend of from about 2% to about 50%, by weight, of (A) a partially or fully alkylated glycoluril derivative having the following structural formula:

wherein n is an integer from 1 to 3 inclusive; R and R4 are individually different alkyl radicals containing from 1 to 6 carbon atoms inclusive; R2 and R3 are separately hydrogen or an alkyl radical having from 1 to 6 carbon atoms inclusive or a phenyl radical; and correspondingly from about 98% to about 50%, by weight, of (B) an organic solvent soluble, normally non-self-crosslinking polymeric material having as reactive groups, any one or more of carboxyl groups, alcoholic hydroxyl groups or amide groups wherein the amount of said groups is at least about 0.5% by weight, and not more than about 25%, by weight, based on the total weight of said polymeric material;
and (C) from about 0.05% to 5.0%, by weight, of an acid catalyst based on the total weight of (A) and (B), wherein said reactive groups of (B) are heat reactive with (A) and wherein said percentages of (A) and (B), by weight, total 100% and are based on the total solids weight of (A) and (B).

3. A composition according to claim 1 or 2 wherein the glycoluril derivative is the diethyl ether, dimethyl ether of tetramethylol glycoluril.

4. An aqueous dispersion of a mixture of from about 2% to about 50%
by weight of (A) a glycoluril derivative having the following structural formula:

wherein n is an integer from 1 to 3 inclusive; R and R4 are individually different alkyl radicals having from 1 to 6 carbon atoms inclusive; R2 and R3 are separately hydrogen or an alkyl radical having from 1 to 6 carbon atoms inclusive or a phenyl radical, and correspondingly from about 98% to about 50% by weight, of (B) a water dispersible, normally non-self-cross-linking polymeric material having as reactive groups, any one or more of carboxyl groups, alcoholic hydroxyl groups or amide groups wherein the amount of said groups is at least about 0.5% by weight, and not more than about 25%, by weight, based on the total weight of said polymeric material; and (C) from about 0.05% to 5.0%, by weight, of an acid catalyst based on the total weight of (A) and (B), wherein said reactive groups of (B) are heat reactive with (A) and wherein said percentages of (A) and (B), by weight, total 100%
and are based on the total solids weight of (A) and (B).

5. The aqueous dispersion according to claim 4 in which the acid catalyst (C) is para toluene sulfonic acid.

6. The aqueous dispersion according to claim 4 in which the acid catalyst (C) is n-dodecylbenzene sulfonic acid.

7. A mixed ether of a tetramethylol glycoluril of the formula:

wherein n is an integer from 1 to 3 inclusive; R and R4 are individually different alkyl radicals of 1 to 6 carbon atoms inclusive; and R2 and R3 are separately hydrogen or an alkyl radical having from 1 to 6 carbon atoms inclusive or a phenyl radical.

8. A mixed ether of tetramethylol glycoluril which is one of the group consisting of diethoxymethyl dipropoxymethyl glycoluril, dibutoxymethyl diethoxymethyl glycoluril and diethoxymethyl dihexoxymethyl glycoluril.

9. A mixed ether according to claim 7 wherein n is 2, R is methyl and R4 is ethyl.

10. A mixed ether according to claim 7 or 8 wherein R2 and R3 are both hydrogen.