Process for the manufacture of pulverizable thermosetting coating agents

Claim 2

IN A PROCESS FOR THE PREPARATION OF A PULVERIZABLE, THERMOSETTING COATING AGENT BASED ON A MIXTURE OF AN ACRYLIC RESIN CONTAINING HYDROXYL GROUPS PREPARED BY SUBSTANCE POLYMERIZATION OF A RESIN-FORMING MONOMER MIXTURE AND A BLOCKED ISOCYANATE, THE IMPROVEMENT WHEREIN SAID PROCESS COMPRISES DISSOLVING IN SAID MONOMER MIXTURE ABOUT 0:1-0.9 EQUIVALENTS OF ISOCYANATE GROUPS BASED ON THE HYDROXYL GROUPS, SAID ISOCYANATE GROUPS DERIVED FROM AT LEAST ONE DI- OR POLYISOCYANATE BLOCKED WITH AT LEAST ONE LACTAM HAVING ABOUT 4-12 CARBON ATOMS, SAID BLOCKED ISOCYANATE HAVING A MELTING POINT OF ABOUT 60* - 150*C, AND POLYMERIZING SAID MONOMER MIXTURE AT A TEMPERATURE BELOW ABOUT 120*C AND IN THE PRESENCE OF A CATALYST.

Claim 3

Process according to claim 1 in which the isocyanate groups are about 0.2-0.5 equivalents based on the hydroxyl groups.

Claim 4

about 10 - 50 weight percent of at least one olefinically unsaturated monomer containing hydroxyl groups and copolymerizable with (1);

Claim 5

about 10 - 50 weight percent of at least one olefinically unsaturated monomer containing hydroxyl groups and copolymerizable with (1);

Claim 6

about 20-40 weight percent of at least one monomer selected from the group consisting of the 2-hydroxyethyl,2-hydroxy-propyl and 4-hydroxybutyl esters of acrylic and methacrylic acid, the amount of said methyl ester of methacrylic acid being about 30 - 60 weight percent based on the total monomer mixture.

Claim 7

about 20-40 weight percent of at least one monomer selected from the group consisting of the 2-hydroxyethyl,2-hydroxy-propyl and 4-hydroxybutyl esters of acrylic and methacrylic acid, the amount of said methyl ester of methacrylic acid being about 30 - 60 weight percent based on the total monomer mixture.

Claim 8

about 0 - 15 weight percent of a monomer selected from the group consisting of methacrylic acid, acrylic acid, methacrylic acid amide, acrylic acid amide, N-substituted methacrylic acid amide, N-substituted acrylic acid amide, styrene, Alpha -methyl styrene, acrylonitrile, vinyl acetate, vinyl propionate, vinyl alkyl ethers having about 1 - 8 carbon atoms in the alkyl group, methacrylonitrile, allyl acetate, vinyl chloride and vinylidene chloride; and dissolving in said monomer mixture about 0.1 - 0.9 equivalents of isocyanate groups based on the hydroxyl groups, said isocyanate groups derived from at least one di- or polyisocyanate blocked with at least one lactam having about 4 - 12 carbon atoms, said blocked isocyanate having a melting point of about 60* - 150* C.; and polymerizing said monomer mixture at a temperature below about 120* C. and in the presence of a catalyst.

Claim 9

about 0 - 15 weight percent of a monomer selected from the group consisting of methacrylic acid, acrylic acid, methacrylic acid amide, acrylic acid amide, N-substituted methacrylic acid amide, N-substituted acrylic acid amide, styrene, Alpha -methyl styrene, acrylonitrile, vinyl acetate, vinyl propionate, vinyl alkyl ethers having about 1 - 8 carbon atoms in the alkyl group, methacrylonitrile, allyl acetate, vinyl chloride and vinylidene chloride; and dissolving in said monomer mixture about 0.1 - 0.9 equivalents of isocyanate groups based on the hydroxyl groups, said isocyanate groups derived from at least one di- or polyisocyanate blocked with at least one lactam having about 4 - 12 carbon atoms, said blocked isocyanate having a melting point of about 60* - 150* C.; and polymerizing said monomer mixture at a temperature below about 120* C. and in the presence of a catalyst.

Claim 10

Process according to claim 1 in which the isocyanate is blocked with epsilon -caprolactam.

Claim 11

Process according to claim 2 in which the isocyanate is blocked with epsilon -caprolactam.

Claim 12

Process according to claim 1 in which the blocked isocyanate is an aliphatic, araliphalatic or cycloaliphatic blocked di- or polyisocyanate.

Claim 13

Process according to claim 3 in which the blocked isocyanate is an aliphatic, araliphalatic or cycloaliphatic blocked di- or polyisocyanate.

Claim 14

Process according to claim 4 in which the blocked isocyanate is an aliphatic, araliphalatic or cycloaliphatic blocked di- or polyisocyanate.

Claim 15

Process according to claim 1 in which the blocked isocyanate is a blocked urethane isocyanate.

Claim 16

Process according to claim 2 in which the blocked isocyanate is a blocked urethane isocyanate.

Claim 17

Process according to claim 3 in which the blocked isocyanate is a blocked urethane isocyanate.

Claim 18

Process according to claim 4 in which the blocked isocyanate is a blocked urethane isocyanate.

Claim 19

Process according to claim 1 in which the monomer mixture having uniformly dissolved therein the blocked isocyanate is polymerized in two steps by: (a) polymerizing said mixture at about 20* - 120* C. to form a syrupy prepolymer and (b) hardening said prepolymer in a layer having a thickness below about 20 mm at a temperature of about 20* - 100* C.

Claim 20

A process for the prepartion of pulverizable, thermosetting coating agents based on an acrylic resin containing hydroxyl groups and a blocked isocyanate, said process comprising preparing a resin-forming monomer mixture coMprising

Claim 21

A process for the prepartion of pulverizable, thermosetting coating agents based on an acrylic resin containing hydroxyl groups and a blocked isocyanate, said process comprising preparing a resin-forming monomer mixture coMprising

Claim 22

Process according to claim 13 in which the monomer mixture comprises

Claim 23

Process according to claim 13 in which component (1) is about 60-80 percent by weight of the monomer mixture.

Claim 24

Process according to claim 15 in which component (2) is about 20-40 percent by weight of the monomer mixture.

Claim 25

Process according to claim 16 in which component (1) is at least one ester of methacrylic acid or acrylic acid having 1 - 20 carbon atoms in the alcohol component, and further in which the alcohol component is derived from an aliphatic or cycloaliphatic alcohol.

Claim 26

Process according to claim 17 in which component (3) is about 1 - 10 percent by weight of the monomer mixture.

Claim 27

Process according to claim 17 in which component (1) is methyl methacrylate.

Claim 28

Process according to claim 19 in which the methyl methacrylate comprises about 30 to about 60 weight percent of the total monomer mixture.

Claim 29

Process according to claim 17 in which the monomer mixture includes a softening ester selected from the group consisting of: acrylic acid methyl ester, acrylic acid ethyl ester, acrylic acid-n-propyl ester, acrylic acid isopropyl ester, acrylic acid butyl ester, acrylic acid-2-ethyl-hexyl ester, acrylic acid-n-octyl ester, acrylic acid dodecyl ester, methacrylic acid butyl ester, methacrylic acid hexyl ester, methacrylic acid-2-ethyl-hexyl ester, methacrylic acid decyl ester and methacrylic acid cyclohexyl ester.

Claim 30

Process according to claim 17 in which component (2) is the 2-hydroxy ethyl ester of acrylic acid, the 2-hydroxy propyl ester of acrylic acid, the 4-hydroxy butyl ester of acrylic acid, the 2-hydroxy ethyl ester of methacrylic acid, the 2-hydroxy propyl ester of methacrylic acid, the 4-hydroxy butyl ester of methacrylic acid, thE hydroxy ethyl ester of maleic acid, the hydroxy propyl ester of maleic acid, the hydroxy butyl ester of maleic acid, the hydroxy ethyl ester of fumaric acid, the hydroxy propyl ester of fumaric acid, the hydroxy butyl ester of fumaric acid, the hydroxy ethyl ester of itaconic acid, the hydroxy propyl ester of itaconic acid, or the hydroxy butyl ester of itaconic acid.

Claim 31

Process according to claim 22 in which the isocyanate is selected from the group consisting of hexamethylene diisocyanate, octamethylene diisocyanate, decamethylene diisocyanate, dodecamethylene diisocyanate, omega , omega ''-diisocyanato-1,4-dimethylbenzene (p-xylylenediisocanate) and isophorone diisocanate.

Claim 32

Process according to claim 22 in which the isocyanate is the adduct formed by reacting two moles of isophorone diisocyanate with one mole of hexanediol, decanediol, tetraethylene glycol, neopentyl glycol or 1,4-bis-hydroxy-methyl cyclohexane, or the adduct formed by reacting three moles of isophorone diisocyanate with one mole of trimethylol propane or hexanetriol.

Claim 33

Process according to claim 23 in which the isocyanate is blocked with epsilon -caprolactam, capryl lactam or lauryl lactam.

Claim 34

Process according to claim 24 in which the isocyanate is blocked with epsilon -caprolactam, capryl lactam or lauryl lactam.

Claim 35

Process according to claim 13 in which the blocked di- or polyisocyanate is substantially soluble at room temperature in the resin-forming monomer mixture.

Claim 36

Process according to claim 17 in which polymerization is conducted at about 20*-120*C.

Claim 37

Process according to claim 23 in which the polymerization is conducted at about 20*-120*C.

Claim 38

Process according to claim 24 in which the polymerization is conducted at a temperature of about 20*-120*C.

Claim 39

Process according to claim 28 in which the reaction mixture is subsequently heated at a temperature of about 100* - 120*C.

Claim 40

Process according to claim 13 in which the monomer mixture includes a radical catalyst selected from the group consisting of peroxides and azo compounds having decomposition temperatures below about 100*C.

Claim 41

Process according to claim 24 in which the molecular weight of the polymerized acrylate resin is adjusted so that the viscosity of a coating agent containing a latent cross-linking component is about 0.1 - 0.3 dl/g.

Claim 42

Process according to claim 33 in which the monomer mixture includes about 0.5 - 3.0 weight percent, based on the weight of the resin-forming monomer mixture, of a molecular weight regulator selected from the group consisting of mercaptans having one or more mercapto groups in the mercaptan molecule.