Thermosetting polyester powder coating compositions

Claim 2

A THERMOSETTING COATING COMPOSITION IN THE FORM OF A POWDER HAVING AN AVERAGE PARTICLE SIZE RANGE OF FROM ABOUT 10 TO ABOUT 300 MICRONS COMPRISING A. FROM ABOUT 50% TO ABOUT 90% BY WEIGHT OF A POLYESTER DERIVED FROM A DICARBOXYLIC ACID COMPONENT, AT LEAST 50 MOL PERCENT OF WHICH IS ISOPHTHALIC ACID, A GLYCOL COMPOSNENT, AT LEAST 50 MOL PERCENT OF WHICH IS 2,2,4TRIMETHYLPENTANE-1,3-DIAL AND FROM ABOUT 3 TO ABOUT 10 MOL PERCENT OF A POLYOL CONTAINING FROM TWO TO 16 CARBON ATOMS AND HAVING AT LEAST THREE PRIMARY HYDROXYL GROUPS, B. FROM ABOUT 5% TO ABOUT 45% BY WEIGHT OF CELLULOSE ACETATE BUTYRATE HAVING A BUTYRL CONTENT OF FROM ABOUT 30 TO ABOUT 55% BY WEIGHT, A HYDROXYL CONTENT OF FROM ABOUT ABOUT 0.1 TO ABOUT 5%, AN ACETYL CONTENT OF FROM ABOUT 0.5 TO 15% BY WEIGHT AND A VISCOSITY OF BETWEEN ABOUT 0.1 AND 30 SECONDS, C. FROM ABOUT 2% TO ABOUT 15% BY WEIGHT TO A MELAMINE CROSSLINKING AGENT, AND D. FROM ABOUT 0.1% TO ABOUT 3% BY WEIGHT OF THE REACTION PRODUCT OF AN ACID AND A COMPOUND CONTAINING OXIRANE GROUPS, SAID POWDER BEING FREE OF APPRECIABLE CROSSLINKING.

Claim 3

A thermosetting coating composition according to claim 1 wherein the powder has an average particle size of from about 20 to about 50 microns.

Claim 4

A thermosetting coating composition according to claim 1 wherein said polyester is derived from (a) from about 50 to about 80 mol percent of a glycol of which at least about 80 percent is 2,2,4-trimethylpentane-1,3-diol, (b) from about 50 to about 20 mol percent of a polyol having from four to 16 carbon atoms and at least three primary hydroxyl groups, and (c) from about 60 to about 90 mol percent of an aromatic dicarboxylic acid of which at least 80 percent is isophthalic acid.

Claim 5

The thermosetting coating composition according to claim 1 wherein said crosslinking agent is hexaalkoxymethylmelamine wherein the alkoxy group contains one and 20 carbon atoms.

Claim 6

A thermosetting coating composition according to claim 4 wherein the alkoxy group contains between one and eight carbon atoms.

Claim 7

A thermosetting coating composition according to claim 1 wherein said reaction product is the reaction product of an aromatic sulfonic acid and a compound containing at least one oxirane group.

Claim 8

A thermosetting coating composition in the form of a powder having an average particle size range of from about 10 to about 300 microns comprising a. a polyester derived from (1) from about 50 to about 80 mol percent of a glycol of which at least about 80 percent is 2,2, 4-trimethylpentane-1,3-diol, (2) from about 50 to about 20 mol percent of a polyol having from four to 16 carbon atoms and at least three primary hydroxyl groups, and (3) from about 60 to about 90 mol percent of an aromatic dicarboxylic acid of which at least 80 percent is isophthalic acid, b. from about 5% to about 45% by weight of cellulose acetate butyrate having a butyryl content of from about 30 to about 55% by weight, a hydroxyl content of from about 0.1 to about 5%, an acetyl content of from about 0.5 to about 15% by weight and a viscosity of between about 0.1 and 30 seconds. c. from about 2% to about 15% by weight of a hexaalkoxymethylmelamine wherein the alkoxy group contains from 1 to 20 carbon atoms, and d. from about 0.1% to about 3% by weight of the reaction product of an aromatic sulfonic acid and a compound containing at least one oxirane group, said powder being free of appreciable crosslinking.

Claim 9

A thermosetting coating composition in the form of a powder having an average particle size range of from about 10 to about 300 microns comprising a. a polyester derived from (1) from about 50 to about 80 mol percent of a glycol of which at least about 80 percent is 2,2, 4-trimethylpentane-1,3-diol, (2) from about 50 to about 20 mol percent of a polyol having from four to 16 carbon atoms and at least three primary hydroxyl groups, and (3) from about 60 to about 90 mol percent of an aromatic dicarboxylic acid of which at least 80 percent is isophthalic acid, b. from about 5% to about 45% by weight of cellulose acetate butyrate having a butyryl content of from about 30 to about 55% by weight, a hydroxyl content of from about 0.1 to about 5%, an acetyl content of from about 0.5 to about 15% by weight and a viscosity of between about 0.1 and 30 seconds. c. from about 2% to about 15% by weight of a hexaalkoxymethylmelamine wherein the alkoxy group contains from 1 to 20 carbon atoms, and d. from about 0.1% to about 3% by weight of the reaction product of an aromatic sulfonic acid and a compound containing at least one oxirane group, said powder being free of appreciable crosslinking.