Ultraviolet curable conformal coatings

Claim 2

An ultraviolet radiation curable conformal coating composition comprising the mixture: Component (A) which comprises a mixture of (1) about 40% to 80% by weight, of a urethane having a free isocyanate group; (2) about 20% to 60% by weight of reactive acrylate diluents; (3) from 0% to about 10% by weight, of UV photoinitiators; (4) from 0% to 10%, by weight, of additives selected from adhesion promoters, pigments, dyes, flow control agents and their mixtures; and Component (B) which comprises a mixture of (1) about 5% to 80% by weight, of an acrylate-epoxy resin which comprises an unsaturated epoxy oligomer having a molecular weight of from 2000 to 5000, where the epoxy in said oligomer is a bisphenol epoxy; (2) about 1% to 10% by weight, of an acrylate-urethane oligomer; (3) about 10% to 94% by weight of reactive acrylate monomers including acrylate monomer having a hydroxy functional group; (4) from 0% to 10%, by weight, of UV photoinitiators; and (5) from 0% to 10%, by weight, of additives selected from adhesion promoters, pigments, dyes, flow control agents and their mixtures; with the proviso that photoinitiator be present in one or both components and that the total percentage weight, based on total composition weight, of said UV photoinitiators plus additives not be less than 1 percent and not exceed about 10 percent.

Claim 3

The composition according to claim 1 wherein said Component (A) includes about 1% to 25%, by weight of polyisocyanate monomers.

Claim 4

The composition according to claim 1 wherein said reactive acrylate diluents have good solvency for said urethane having a free isocyanate group.

Claim 5

The composition according to claim 1 wherein said reactive acrylate monomers are selected from the group consisting of acrylate monomers having a hydroxy functional group, resin soluble acrylate monomers, acrylate monomers having low moisture permeability, acrylate monomers having ether linkages, and mixtures thereof.

Claim 6

The composition according to claim 1 wherein Component (B) includes about 5% to 80%, by weight, of an epoxy resin.

Claim 7

The composition according to claim 1 wherein Component (B) includes about 1% to 10%, by weight, of a polyol.

Claim 8

The composition according to claim 1 wherein Component (B) includes about 5% to 80%, by weight, of an acrylate epoxy urethane.

Claim 9

The composition according to claim 1 wherein said reactive acrylate monomers include about 10% to 50%, by weight, of an acrylate monomer having a hydroxy functional group.

Claim 10

The composition according to claim 4 ,wherein said reactive acrylate monomers include about 10% to 50%, by weight, of a resin soluble acrylate monomer.

Claim 11

The composition according to claim 4 wherein said reactive acrylate monomers include about 10% to 50% by weight, of an acrylate having low moisture permeability.

Claim 12

The composition according to claim 4 wherein said reactive acrylate monomers include about 1% to 15% by weight, of an acrylate monomer having ether linkages.

Claim 13

The composition according to claim 1 wherein said urethane having a free isocyanate group in Component (A) is prepared by reacting alcohols or polyols with one stoichiometric equivalent of excess polyisocyanate, in the presence of from 0.01% to 0.1% by weight, based on Component (A), of an inhibitor, and where the composition has a viscosity in the range of 200 cps. to 300 cps. over an 8 hour period at room temperature.

Claim 14

The composition according to claim 12 wherein said alcohols or polyols contain an acrylate functional group.

Claim 15

The composition according to claim 13 wherein said polyol is hydroxyethyl acrylate and said polyisocyanate is toluene diisocyanate.

Claim 16

The composition according to claim 1 wherein said Component (A) reactive acrylate diluents are free of active hydrogen groups.

Claim 17

The composition according to claim 1 wherein said reactive acrylate diluents are monoacrylate monomers or diacrylate monomers.

Claim 18

The composition according to claim 1 wherein said reactive acrylate diluents of Component (A) are selected from the group consisting of phenoxy ethyl acrylate, hexanediol diacrylate, phenol ethoxylate monoacrylate tetraethylene glycol diacrylate, ethylacrylate, 2-(2-ethoxy ethoxy) tripropyl glycol diacrylate and mixtures thereof.

Claim 19

The composition according to claim 1 wherein said acrylate epoxy resin is prepared by reacting an anhydride or a diacid with a hydroxy acrylate followed by reaction with a bisphenol epoxy.

Claim 20

The composition according to claim 1 wherein said acrylate urethane oligomer is prepared by reacting a diisocyanate with a hydroxy acrylate to form a urethane followed by reaction of said urethane with caprolactam.

Claim 21

A composition according to claim 1 wherein said photoinitiators are selected from the group consisting of glyoxylate derivatives, benzoin ether derivatives, alpha-acryloxime ester derivatives, acetophenone derivatives, ketone-amine combinations and mixtures thereof, where the composition has a viscosity in the range of 200 cps. to 300 cps. over an 8 hour period of room temperature, and where the composition is capable of U.V. cure in shadow areas hidden from a U.V. light source.

Claim 22

The composition according to claim 8 wherein said acrylate monomer having a hydroxy functional group is selected from the group consisting of hydroxyl ethyl acrylate, 3-hydroxyl propyl acrylate, 2-hydroxymethacrylate, hydroxy-beta-carboxy ethyl acrylate, 3-hydroxy methacrylate, hydroxyhexyl acrylate, hydroxy octyl methacrylate, 2-hydroxy propyl acrylate, 2-hydroxy ethyl methacrylate, and mixtures thereof.

Claim 23

The composition according to claim 9 wherein said resin soluble acrylate monomers are selected from the group consisting of phenoxy ethyl acrylate, phenol ethoxylate monoacrylate, tetrahydrofurfuryl methacrylate, n-hexylmethacrylate, and mixtures thereof.

Claim 24

The composition according to claim 10 wherein said acrylate having low moisture permeability is an alkylene diacrylate.

Claim 25

The composition according to claim 23 wherein said acrylates having low moisture permeability are selected from the group consisting of 1,6-hexanediol diacrylate, ethylene glycol diacrylate, 1,3-butylene glycol diacrylate, 1,4-butanediol diacrylate, neopentyl glycol diacrylate, and mixtures thereof.

Claim 26

The composition according to claim 12 wherein said acrylate monomers in Component (B), have ether linkages and are selected from the group consisting of ethylene glycol diacrylate, tetraethylene glycol diacrylate, diethylene glycol diacrylate, ethoxylated bisphenol A diacrylate, tripropylene glycol diacrylate and mixtures thereof.

Claim 27

The composition according to claim 1 wherein said flow control agent is a fluorocarbon.

Claim 28

The composition according to claim 1 wherein said adhesion promoter is selected from the group consisting of acrylate mercaptan, acrylate phosphate and mixtures thereof.

Claim 29

A composition according to claim 1 in the form of a thin coating on a substrate.

Claim 30

A composition according to claim 28 wherein said substrate is a printed wiring board.

Claim 31

The composition according to claim 5 wherein said epoxy resin is a bisphenol epoxy.

Claim 32

The composition according to claim 6 wherein said polyol is an aliphatic having 1 to 10 carbons or aromatic.

Claim 33

The composition according to claim 7 wherein said acrylate epoxy urethane is the reaction product of a bisphenol epoxy and isocyanato ethyl methacrylate.

Claim 34

The composition according to claim 1 wherein Component (A) and Component (B) are present in about equal parts by weight.

Claim 35

The composition according to claim 1 wherein Component (A) and Component (B) are present in about a 1 to 2 ratio, by weight.

Claim 36

The composition according to claim 1 wherein the composition consists essentially of the mixture of Component (A) and Component (B) and Component (B) is present in an amount at least equal to Component (A).

Claim 37

The composition according to claim 12 wherein the weight ratio of Component (A):Component (B) is from about 1:1 to about 1:2, the alcohols or polyols may possess acrylate functional groups, and Component (A) consists essentially of a mixture of (1), (2), (3) and (4).

Claim 38

An ultraviolet radiation curable composition consisting essentially of the mixture: Component (A) which consists essentially of a mixture of (1) about 40% to 80% by weight, of a urethane having a free isocyanate group consisting essentially of the reaction mixture of alcohols or polyols with one stoichiometric equivalent of excess polyisocyanate in the presence of an inhibiter, where the alcohols or polyols may possess acrylate functional groups; (2) about 20% to 60% by weight of reactive acrylate diluents free of active hydrogen and containing no more than three acrylate functional groups; (3) from 0% to about 10%, by weight, of UV photoinitiators; (4) from 0% to 10%, by weight, of additives selected form adhesion promoters, pigments, dyes, flow control agents and their mixtures; and Component (B) which comprises a mixture of (1) about 5% to 80% by weight, of an acrylate-epoxy resin which comprises an unsaturated epoxy oligomer having a molecular weight of from 2000 to 5000, where the epoxy in said oligomer is a bisphenol epoxy; (2) about 1% to 10% by weight, of an acrylate-urethane oligomer; (3) reactive acrylate monomers including from 10% to 50% by weight of acrylate monomer having a hydroxy functional group; (4) from 0% to 10%, by weight, or UV photoinitiators; and (5) from 0% to 10%, by weight, of additives selected from adhesion promoters, pigments, dyes, flow control agents and their mixtures; with the proviso that photoinitiator be present in one or both components and that the total percentage weight, based on total composition weight, of said UV photoinitiators plus additives not be less than 1 percent and not exceed about 10 percent; and where the weight ratio of Component (A):Component (B) of from about 1:1 to about 1:2.

Claim 39

An ultraviolet radiation curable composition consisting essentially of the mixture: Component (A) which consists essentially of a mixture of (1) about 40% to 80% by weight, of a urethane having a free isocyanate group consisting essentially of the reaction mixture of alcohols or polyols with one stoichiometric equivalent of excess polyisocyanate in the presence of an inhibiter, where the alcohols or polyols may possess acrylate functional groups; (2) about 20% to 60% by weight of reactive acrylate diluents free of active hydrogen and containing no more than three acrylate functional groups; (3) from 0% to about 10%, by weight, of UV photoinitiators; (4) from 0% to 10%, by weight, of additives selected form adhesion promoters, pigments, dyes, flow control agents and their mixtures; and Component (B) which comprises a mixture of (1) about 5% to 80% by weight, of an acrylate-epoxy resin which comprises an unsaturated epoxy oligomer having a molecular weight of from 2000 to 5000, where the epoxy in said oligomer is a bisphenol epoxy; (2) about 1% to 10% by weight, of an acrylate-urethane oligomer; (3) reactive acrylate monomers including from 10% to 50% by weight of acrylate monomer having a hydroxy functional group; (4) from 0% to 10%, by weight, or UV photoinitiators; and (5) from 0% to 10%, by weight, of additives selected from adhesion promoters, pigments, dyes, flow control agents and their mixtures; with the proviso that photoinitiator be present in one or both components and that the total percentage weight, based on total composition weight, of said UV photoinitiators plus additives not be less than 1 percent and not exceed about 10 percent; and where the weight ratio of Component (A):Component (B) of from about 1:1 to about 1:2.

Claim 40

The composition according to claim 37 where polyisocyanate monomer is also added to the mixture of Component (A), and where the composition has a viscosity in the range of 200 cps. to 300 cps. over an 8 hour period at room temperature, and where part (1) of Component (A) consists essentially of the reaction mixture of hydroxy acrylate with one stoichiometric equivalent of excess polyisocyanate in the presence of from 0.01% to 0.1% by weight, based on Component (A) of an inhibitor.

Claim 41

The composition according to claim 37 wherein the urethane of Component (A) is a reaction mixture of hydroxy ethyl acrylate, toluene diisocyanate and an inhibitor; the reactive acrylate diluent is selected from the group consisting of phenoxy ethyl acrylate and hexane diol diacrylate; and the weight ratio of Component (A):Component (B) is about 1:2, and where the composition is capable of U.V. cure in shadow areas hidden from a U.V. light source.

Claim 42

An ultraviolet radiation curable, low viscosity, conformal coating composition consisting essentially of the mixture: Component (A) which consists essentially of a mixture of (1) about 40% to 80% by weight, of a urethane having a free isocyanate group, where said urethane is a reaction mixture of hydroxy ethyl acrylate, toluene diisocyanate and an inhibitor; (2) about 20% to 60% by weight of phenoxy ethyl acrylate; (3) from 0% to about 10% by weight, of UV photoinitiators; (4) from 0% to 10%, by weight, of additives selected from adhesion promoters, pigments, dyes, flow control agents and their mixtures; and Component (B) which comprises a mixture of (1) about 5% to 80% by weight, of an acrylate-epoxy resin which comprises an unsaturated epoxy oligomer having a molecular weight of from 2000 to 5000, where the epoxy in said oligomer is a bisphenol epoxy; (2) about 1% to 10% by weight, of an acrylate-urethane oligomer; (3) about 10% to 94% by weight of reactive acrylate monomers from the group consisting of hydroxy propyl methacrylate, phenoxy ethyl acrylate, hexane diol diacrylate, and tetra ethylene glycol diacrylate; (4) from 0% to 10%, by weight, of UV photoinitiators; and (5) from 0% to 10%, by weight, of additives selected from adhesion promoters, pigments, dyes, flow control agents and their mixtures; with the proviso that photoinitiator be present in one or both components and that the total percentage weight, based on total composition weight, of said UV photoinitiators plus additives not be less than 1 percent and not exceed about 10 percent; where the viscosity is in the range of 200 cps. to 300 cps. at room temperature, and where the weight ratio of Component (A):Component (B) of from about 1:1 to about 1:2.

Claim 43

An ultraviolet radiation curable, low viscosity, conformal coating composition consisting essentially of the mixture: Component (A) which consists essentially of a mixture of (1) about 40% to 80% by weight, of a urethane having a free isocyanate group, where said urethane is a reaction mixture of hydroxy ethyl acrylate, toluene diisocyanate and an inhibitor; (2) about 20% to 60% by weight of phenoxy ethyl acrylate; (3) from 0% to about 10% by weight, of UV photoinitiators; (4) from 0% to 10%, by weight, of additives selected from adhesion promoters, pigments, dyes, flow control agents and their mixtures; and Component (B) which comprises a mixture of (1) about 5% to 80% by weight, of an acrylate-epoxy resin which comprises an unsaturated epoxy oligomer having a molecular weight of from 2000 to 5000, where the epoxy in said oligomer is a bisphenol epoxy; (2) about 1% to 10% by weight, of an acrylate-urethane oligomer; (3) about 10% to 94% by weight of reactive acrylate monomers from the group consisting of hydroxy propyl methacrylate, phenoxy ethyl acrylate, hexane diol diacrylate, and tetra ethylene glycol diacrylate; (4) from 0% to 10%, by weight, of UV photoinitiators; and (5) from 0% to 10%, by weight, of additives selected from adhesion promoters, pigments, dyes, flow control agents and their mixtures; with the proviso that photoinitiator be present in one or both components and that the total percentage weight, based on total composition weight, of said UV photoinitiators plus additives not be less than 1 percent and not exceed about 10 percent; where the viscosity is in the range of 200 cps. to 300 cps. at room temperature, and where the weight ratio of Component (A):Component (B) of from about 1:1 to about 1:2.

Claim 44

The composition according to claim 40 where polyisocyanate monomer is also added to the mixture of Component (A), where the composition has a viscosity in the range of 200 cps. to 300 cps. over an 8 hour period at room temperature, and were inhibitor in Component (A) is present in the range of from 0.01% to 0.1% by weight, based on Component (A), and where the composition is capable of U.V. cure in shadow areas hidden from a U.V. light source.