Polycyanate esters of polyhydric phenols blended with thermoplastic polymers

Claim 2

Curable compositions comprising a blend of: (A) a polycyanate ester of a polyhydric phenol; and (B) an amorphous, aromatic thermoplastic resin which is initially soluble in the blend but which phase separates during cyclotrimerization of the polycyanate ester wherein B is present in the amount of about 5 to about 25 weight percent based on the weight of A and B.

Claim 3

The composition of Claim 1 wherein the thermoplastic resin has a heat deflection temperature of at least 150°C.

Claim 4

The composition of Claim 1 wherein the thermoplastic resin is selected from the group consisting of polysulfones, polyetherimides, wholly aromatic polyesters, polyether sulfones, wholly imidized polymers of dianhydrides and asymmetric diamines, polyarylethers and polyarylformals.

Claim 5

The composition of Claim 3 wherein the thermoplastic resins are terminated with hydroxyl groups, amine groups, or epoxy groups.

Claim 6

The composition of claim 1 wherein the polycyanate ester is a polycyanate ester of a dihydric phenol selected from the group consisting of 4,4′-dihydroxydiphenyl propane, 4,4′-dihydroxydiphenyl oxide, 4,4′-methylene bis (2,6-dimethylphenol) and bis(4-hydroxyphenyl)-1,1-ethane.

Claim 7

The composition of Claim 1 wherein up to about 50 weight percent of the polycyanate ester is replaced with an epoxy resin.

Claim 8

The composition of Claim 6 wherein the epoxy resin is a polyglycidyl ether of a polyhydric phenol.

Claim 9

The composition of Claim 7 wherein the epoxy resin is a diglycidyl ether of p,p′-dihydroxydiphenyl propane.

Claim 10

The composition of Claim 1 wherein up to about 20 weight percent of the polycyanate ester is replaced with a bismaleimide.

Claim 11

The composition of Claim 1 which contains a polycyanate curing catalyst.

Claim 12

The composition of Claim 10 wherein the catalyst is an active hydrogen class catalyst.

Claim 13

The composition of Claim 10 wherein the catalyst is a metal coordination class catalyst.

Claim 14

A cured composition comprised of the composition of Claim 1 having G IC values in excess of 1.5 inch-pounds/inch².

Claim 15

The cured composition of Claim 13 wherein the G IC values are about 3 to about 6 inch pounds/inch².

Claim 16

A process for preparing a cured composition which comprises: A) forming a solution of (a) a polycyanate ester of a polyhydric phenol and (b) an amorphous, aromatic thermoplastic resin, B) adding a curing catalyst, C) heating the solution at a temperature of about 200°F to about 350°F for a time sufficient for phase separation of (a) and (b) to occur and to gel the polycyanate ester and, D) curing the gel at a temperature of about 350°F to about 500°F for about 30 minutes to about 8 hours.

Claim 17

A process for preparing a cured composition which comprises: A) forming a solution of (a) a polycyanate ester of a polyhydric phenol and (b) an amorphous, aromatic thermoplastic resin, B) adding a curing catalyst, C) heating the solution at a temperature of about 200°F to about 350°F for a time sufficient for phase separation of (a) and (b) to occur and to gel the polycyanate ester and, D) curing the gel at a temperature of about 350°F to about 500°F for about 30 minutes to about 8 hours.

Claim 18

The process of Claim 15 wherein the thermoplastic resin has a heat deflection temperature of at least 150°C.

Claim 19

The process of Claim 16 wherein the thermoplastic resin is selected from the group consisting of polysulfones, polyetherimides, wholly aromatic polyesters, polyether sulfones, wholly imidized polymers of dianhydrides and asymmetric diamines, polyarylethers and polyarylformals.

Claim 20

The process of Claim 17 wherein the thermoplastic resins are terminated with hydroxyl groups, amine groups, or epoxy groups.

Claim 21

The process of Claim 15 wherein the polycyanate ester is a polycyanate ester of a dihydric phenol selected from the group consisting of 4,4′-dihydroxydiphenyl propane, 4,4′-dihydroxydiphenyl oxide, 4,4′-methylene bis (2,6-dimethylphenol) and bis (4-hydroxyphenyl) -1,1-ethane.

Claim 22

The process of Claim 15 wherein the catalyst is an active hydrogen class catalyst.

Claim 23

The process of Claim 15 wherein the catalyst is a metal coordination class catalyst.