Water-borne, alkali-developable, photoresist coating compositions and their preparation

Claim 2

A photoresist coating composition comprising (a) a multifunctional acrylate monomer, (b) a photoinitiator, and (c) a latex of a water insoluble carboxylated acrylate copolymer having an acid number greater than about 80, wherein further the latex has been neutralized with a base in an amount of at least about 0.25 equivalents per equivalent of acid, and wherein (a), (b), and (c) together are a waterborne, stable, homogeneous coating mixture can form a uniform, homogeneous photoresist layer which is aqueous alkali developable and, after crosslinking, is resistant to etch and plating solutions.

Claim 3

The coating composition of claim 1 which has a percent solids level of at least about 25%.

Claim 4

The coating composition of claim 1 wherein the copolymer of (c) has a glass transition temperature greater than 60° C., the ratio of the amount of polymer:monomer is about 58:42 or greater, and the stable homogeneous coating mixture is a contact imageable photoresist coating composition.

Claim 5

The coating composition of claim 1 which also has a photosensitizer.

Claim 6

The coating composition of claim 1 wherein the amount of base is in the range of from 0.4 to 0.6 equivalents per equivalent of acid to provide a coating composition that can be applied by screen printing.

Claim 7

The coating composition of claim 1 wherein the amount of base is in the range of from 0.3 to 0.5 equivalents per equivalent of acid to provide a coating composition that can be applied by dip-coating.

Claim 8

The coating composition of claim 1 wherein the base is ammonia, sodium hydroxide, potassium hydroxide, 4-methylmorpholine, 2-amino-2-methyl-1-propanol, 2-di-methylamino-2-methyl-1-propanol, monoethanol amine, N,N-dimethylethanolamine, methyldiethanol amine, morpholine.

Claim 9

The coating composition of claim 1 wherein the photoinitiator is selected from the group consisting of [4-(4-methylphenylthio)phenyl] phenylmethanone, orthochloro HABI, P,P'-bis-dimethylamino benzophenone, benzophenone, 2,2-dimethoxy-2-phenylacetophenone, 1-hydroxycyclohexyl phenyl ketone, isopropylthioxanthone (mixture of 2- and 4-isomers) and 2-methyl-1-[4-(methylthio) phenyl]-2-morpholinopropanone-1.

Claim 10

The coating composition of claim 7 wherein the base is ammonia.

Claim 11

The coating composition of claim 1 wherein the multifunctional acrylate monomer is water insoluble.

Claim 14

The method of claim 11 wherein the water insoluble carboxylated acrylate copolymer has a glass transition temperature greater than 60° C.; wherein further the ratio of the amount of polymer:monomer is about 58:42 or greater, and the stable, homogenous, water-borne photoresist coating mixture formed provides contact imageability.

Claim 15

The method of claim 11 wherein the base was added in an amount in the range of from 0.4 to 0.6 equivalents per equivalent of acid.

Claim 16

The method of claim 11 wherein the base was added in an amount in the range of from 0.3 to 0.5 equivalents per equivalent of acid.

Claim 17

The method of claim 11 wherein the base added was ammonia.

Claim 18

The method of claim 11 wherein a photosensitizer is also added.

Claim 19

The method of claim 11 wherein before step (b) a monomer pre-mix was formed by mixing the photoinitiator with the monomer while heating, and then as step (b) this monomer pre-mix was added.

Claim 20

An aqueous liquid photoresist for dip-coating or spraying comprising in parts by weight: ______________________________________ A water insoluble carboxylated acrylic 55-75 parts copolymer latex (30-50% solids) Water 25-30 parts 28% aqueous ammonia 1.0-3.6 parts A multifunctional acrylate monomer 8-12 parts A water immiscible photoinitiator 1.5-3 parts A photosensitizer 0.2-0.8 parts ______________________________________ further providing that the latex has an acid number greater than about 80 and that the aqueous ammonia provides at least about 25% neutralization.

Claim 21

An aqueous liquid photoresist for dip-coating or spraying comprising in parts by weight: ______________________________________ A water insoluble carboxylated acrylic 55-75 parts copolymer latex (30-50% solids) Water 25-30 parts 28% aqueous ammonia 1.0-3.6 parts A multifunctional acrylate monomer 8-12 parts A water immiscible photoinitiator 1.5-3 parts A photosensitizer 0.2-0.8 parts ______________________________________ further providing that the latex has an acid number greater than about 80 and that the aqueous ammonia provides at least about 25% neutralization.

Claim 22

An aqueous liquid photoresist for screen printing comprising in parts by weight: ______________________________________ A water insoluble carboxylated acrylic 70-85 parts copolymer latex (30-50% solids) Water 5-10 parts 28% aqueous ammonia 1.4-4.0 parts A multifunctional acrylate monomer 10-15 parts A water immiscible photoinitiator 1.5-3 parts A photosensitizer 0.2-0.8 parts ______________________________________ further providing that the latex has an acid number greater than about 80 and that the aqueous ammonia provides at least about 25% neutralization.

Claim 23

An aqueous liquid photoresist for screen printing comprising in parts by weight: ______________________________________ A water insoluble carboxylated acrylic 70-85 parts copolymer latex (30-50% solids) Water 5-10 parts 28% aqueous ammonia 1.4-4.0 parts A multifunctional acrylate monomer 10-15 parts A water immiscible photoinitiator 1.5-3 parts A photosensitizer 0.2-0.8 parts ______________________________________ further providing that the latex has an acid number greater than about 80 and that the aqueous ammonia provides at least about 25% neutralization.