# US 4,397,989 A · High solids coating composition of an acrylic polymer a polyester polyol and an alkylated melamine crosslinking agent

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- Number: US 4,397,989 A
- Document ID: US4397989A
- Status: Granted
- Kind: A
- Application number: 06/346,737
- Filed: 1982-02-08
- Granted: 1983-08-09
- Earliest claimed: 1982-02-08
- Assignees: E. I. Du Pont de Nemours and Company
- Inventors: Paul L. Adesko
- Web page: https://patentgrep.com/patent/US4397989A

## CPC

- C09D 133/066: {containing -OH groups}
- C09D 167/02: Polyesters derived from dicarboxylic acids and dihydroxy compounds (C09D167/06 takes precedence)
- C08L 61/32: Modified amine-aldehyde condensates
- C08L 67/02: Polyesters derived from dicarboxylic acids and dihydroxy compounds (C08L67/06 takes precedence)
- Y10T 428/31794: Of cross-linked polyester
- C09D: COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR (cosmetics A61K; processes for applying liquids or other fluent materials to surfaces, in general, B05D; staining wood B27K5/02; glazes or vitreous enamels C03C; natural resins, French polish, drying-oils, driers, turpentine, per se, C09F; polishing compositions other than French polish, ski waxes C09G; adhesives or use of materials as adhesives C09J; materials for sealing or packing joints or covers C09K3/10; materials for stopping leaks C09K3/12; processes for the electrolytic or electrophoretic production of coatings C25D)
- C08L: COMPOSITIONS OF MACROMOLECULAR COMPOUNDS (compositions based on polymerisable monomers C08F, C08G; artificial filaments or fibres D01F; textile treating compositions D06)
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

The high solids coating composition contains at least 40% by weight of a binder of film-forming constituents in which the constituents are of (1) an acrylic polymer of styrene or methyl methacrylate or mixtures thereof, an alkyl acrylate or an alkyl methacrylate and a hydroxyl alkyl acrylate or methacrylate (2) a polyester polyol and (3) an alkylated melamine formaldehyde crosslinking agent and optionally, an acid catalyst; the composition is particularly useful as a primer or an exterior finish for automobiles, trucks, airplanes and can be used as an appliance finish and for coil coatings.

## Claims

### Claim 1

A high solids coating composition comprising at least 40% by weight of a binder of film-forming constituents and up to 60% by weight of a nonaqueous liquid carrier; in which the film-forming constituents consist essentially of about
(1) 10-50% by weight, based on the weight of the binder, of an acrylic polymer consisting essentially of
(a) 10-50% by weight, based on the weight of the polymer, of styrene, methylmethacrylate or mixtures thereof;
(b) 30-70% by weight, based on the weight of the polymer, of an alkyl methacrylate, or an alkyl acrylate each having 2-12 carbon atoms in the alkyl group, and
(c) 15-50% by weight, based on the weight of the polymer, of a hydroxyl alkyl acrylate or methacrylate having 2-4 carbon atoms in the alkyl group; and
the polymer having a number average molecular weight of 500-20,000;
(2) 10-60% by weight, based on the weight of the binder, of a polyester polyol having a number average molecular weight of 1500 or less and an acid number of 20 or less which is the reaction product of
(a) neopentyl glycol and at least one other hindered diol containing two methylol groups wherein each methylol group is attached directly to a cycloaliphatic or aromatic structure or to a tertiary carbon atom, the molar ratio of neopentyl glycol to hindered diol being 2:1 to 6:1, and
(b) a mixture of aromatic and aliphatic dicarboxylic acids wherein the molar ratio of aromatic acid to aliphatic acid is from 1.5:1 to 10:1,
wherein the molar ratio of (a) to (b) is from 1.3:1 to 1.9:1 and wherein the polyol has a hydroxy content of about 3.0-10.0% by weight;
(3) 15-40% by weight, based on the weight of the binder, of a fully or partially alkylated melamine formaldehyde crosslinking agent having 1-4 carbon atoms in the alkyl group.

### Claim 2 (depends on 1)

The coating composition of claim 1 containing pigment in addition to the binder in the amount of about 0.1-50% by weight, based on the weight of the coating composition.

### Claim 3 (depends on 1)

The coating composition of claim 1 in which the acrylic polymer consists essentially of
15-25% by weight of styrene,
45-55% by weight of butylmethacrylate, and
25-35% by weight of a hydroxy ethyl
acrylate.

### Claim 4 (depends on 3)

The coating composition of claim 3 wherein the polyester polyol comprises the esterification product of monoester of neopentyl glycol hydroxy pivalic acid, neopentyl glycol, phthalic anhydride, isophthalic acid and adipic acid.

### Claim 5 (depends on 4)

The coating composition of claim 4 wherein the polyester polyol is a blend of the polyester of claim 4 and a second ester mixture of the formula: ##STR3## where n=0-4 and m=1-6.

### Claim 6 (depends on 5)

The coating composition of claim 5 wherein the second polyester polyol is the condensation product of 2,2,4-trimethyl-1,3-pentane diol and a mixture of succinic, glutaric, and adipic acids in a weight ratio of about 1:2:1.

### Claim 7 (depends on 1, 3, 4)

The coating composition of claims 1, 3, 4, or 5 wherein the binder is
(1) 15-45% by weight, based on the weight of the binder, of the acrylic polymer,
(2) 25-45% by weight, based on the weight of the binder, of the polyester polyol, and
(3) 20-35% by weight, based on the weight of the binder, of the alkylated melamine formaldehyde crosslinking agent.

### Claim 8 (depends on 4)

The coating composition of claim 4 in which the crosslinking agent is hexamethoxybutoxy methyl melamine.

### Claim 9 (depends on 1, 8)

The coating composition of claim 1 or 8 containing about 0.1-2.0% by weight of an acid catalyst.

### Claim 10 (depends on 9)

The coating composition of claim 9 in which the catalyst is paratoluene sulfonic acid, dodecyl benzene sulfonic acid, dinonyl naphthalene disulfonic acid or an amine adduct of said acids.

### Claim 11 (depends on 1)

The coating composition of claim 1 containing about 0.1-5% by weight, based on the weight of the binder, of an ultraviolet light stabilizer.

### Claim 12 (depends on 1)

The coating composition of claim 1 containing about 0.1-5% by weight, based on the weight of the binder, of an antioxidant.

### Claim 13 (depends on 2)

A substrate coated with a fully cured layer of the composition of claim 2.
