Metal carboxylate/alcohol curing catalyst for polycyanate ester of polyhydric phenol

Claim 2

A curable composition comprising a polycyanate ester of a polyhydric phenol and a catalyst blend comprising a liquid solution of a metal carboxylate in a monohydric alcohol wherein the metal is a coordinating transition metal having 9 or more electrons in its next-to-outermost shell, wherein the carboxylate contains 4 to about 24 carbon atoms and wherein the monohydric alcohol is liquid at room temperature, has a boiling point greater than 160° C. at 760 mm Hg pressure and has a solubility of less than 10 percent by weight in water.

Claim 3

The composition of claim 1 wherein the metal is present in the amount of about 0.001 to about 0.5 part by weight per 100 parts by weight of the polycyanate and wherein the monohydric alcohol is present in the amount of about 3 to about 100 milliequivalents of active hydrogen per equivalent of cyanate group.

Claim 4

The composition of claim 2 wherein the blend of metal carboxylate and monohydric alcohol is present in the amount of about 0.5 to about 20 parts by weight per 100 parts by weight of the polycyanate ester.

Claim 5

The composition of claim 3 wherein the blend is present in the amount of about 1.0 to about 8 parts by weight per 100 parts by weight of the polycyanate ester.

Claim 6

The composition of claim 1 wherein the metal is selected from the group consisting of divalent copper, manganese, tin, lead, zinc, cobalt and nickel, trivalent iron and chromium, and tetravalent titanium.

Claim 7

The composition of claim 1 wherein the metal is selected from the group consisting of copper, manganese, nickel, cobalt and zinc.

Claim 8

The composition of claim 1 wherein the metal carboxylate is copper naphthenate.

Claim 9

The composition of claim 1 wherein the monohydric alcohol is selected from the group consisting of aliphatic alcohols which contain at least 5 carbon atoms, aryl substituted alcohols, cycloaliphatic alcohols and alkyl ether glycols wherein the alkyl group contains at least 5 carbon atoms.

Claim 10

The composition of claim 1 wherein the monohydric alcohol is benzyl alcohol.

Claim 11

The composition of claim 1 wherein the polycyanate ester is the dicyanate ester of p,p'-dihydroxydiphenyl propane.

Claim 12

The composition of claim 1 wherein the polycyanate ester is the dicyanate ester of 4,4'-methylenebis(2,6-dimethylphenol).

Claim 13

The composition of claim 1 wherein up to 70 weight percent of the polycyanate ester of the polyhydric phenol is replaced with a glycidyl ether of a polyhydric phenol.

Claim 14

The composition of claim 12 wherein the glycidyl ether is the diglycidyl ether of p,p'-dihydroxydiphenyl propane.

Claim 15

A process for preparing a cured composition which comprises mixing a polycyanate ester of a polyhydric phenol with a catalyst blend comprising a liquid solution of a metal carboxylate in a monohydric alcohol, wherein the metal is a coordinating transition metal having 9 or more electrons in its next-to-outermost shell, wherein the carboxylate contains 4 to about 24 carbon atoms and wherein the monohydric alcohol is liquid at room temperature, has a boiling point greater than 160° C. at 760 mm Hg pressure and has a solubility of less than 10 percent by weight in water, then heating the resulting mixture at a temperature of about 250° to about 450° F. for a time sufficient to cure the mixture.

Claim 16

A process for preparing a cured composition which comprises mixing a polycyanate ester of a polyhydric phenol with a catalyst blend comprising a liquid solution of a metal carboxylate in a monohydric alcohol, wherein the metal is a coordinating transition metal having 9 or more electrons in its next-to-outermost shell, wherein the carboxylate contains 4 to about 24 carbon atoms and wherein the monohydric alcohol is liquid at room temperature, has a boiling point greater than 160° C. at 760 mm Hg pressure and has a solubility of less than 10 percent by weight in water, then heating the resulting mixture at a temperature of about 250° to about 450° F. for a time sufficient to cure the mixture.

Claim 17

The process of claim 14 wherein the mixture is cured by stepwise heating wherein the first step or gelation step is conducted at a temperature of about 150° to about 350° F. and wherein the second step or curing step is conducted at a temperature of about 300° to about 450° F.

Claim 18

The process of claim 15 wherein the mixture is post-cured at a temperature of about 400° to about 500° F.

Claim 19

The process of claim 14 wherein the metal is present in the amount of about 0.001 to about 0.5 part by weight per 100 parts by weight of the polycyanate and wherein the monohydric alcohol is present in the amount of about 3 to about 100 milliequivalents of active hydrogen per equivalent of cyanate group.

Claim 20

The process of claim 17 wherein the blend of metal carboxylate and monohydric alcohol is present in the amount of about 0.5 to about 20 parts by weight per 100 parts by weight of the polycyanate ester.

Claim 21

The process of claim 18 wherein the blend is present in the amount of about 1.0 to about 8 parts by weight per 100 parts by weight of the polycyanate ester.

Claim 22

The process of claim 14 wherein the metal is selected from the group consisting of divalent copper, manganese, tin, lead, zinc, cobalt and nickel, trivalent iron and chromium, and tetravalent titanium.

Claim 23

The process of claim 14 wherein the metal carboxylate is copper naphthenate.

Claim 24

The process of claim 14 wherein the monohydric alcohol is selected from the group consisting of aliphatic alcohols which contain at least 5 carbon atoms, aryl substituted alcohols, cycloaliphatic alcohols and alkyl ether glycols wherein the alkyl group contains at least 5 carbon atoms.

Claim 25

The process of claim 14 wherein the monohydric alcohol is benzyl alcohol.

Claim 26

The process of claim 14 wherein the polycyanate ester is the dicyanate ester of p,p'-dihydroxydiphenyl propane.

Claim 27

The process of claim 14 wherein the polycyanate ester is the dicyanate ester of 4,4'-methylenebis (2,6-dimethylphenol).

Claim 28

The process of claim 14 wherein up to 70 weight percent of the polycyanate ester of the polyhydric phenol is replaced with a glycidyl ether of a polyhydric phenol.

Claim 29

The process of claim 26 wherein the glycidyl ether is the diglycidyl ether of p,p'-dihydroxydiphenyl propane.