Thermosetting resin composition, cured resin product, prepreg and fiber-reinforced plastic

A resin composition comprising a thermosetting resin (A), a curing agent B) and a thermoplastics resin (C), which is soluble in the resin (A), wherein the thermoplastics resin (C) is a copolymer selected from the group consisting of block copolymers and graft copolymers each comprising a molecular chain compatible with, and a molecular chain incompatible with, at least one of the thermosetting resin (A) and curing agent (B) wherein the thermoplastic resin (C) is selected from the group consisting of polyimides, polyamides and polyethers each having a siloxane molecular chain, wherein the thermoplastics resin (C) additionally contains residues having a structure of formula (a) ##STR10## where R.sub.1 and R.sub.1 ' are, independently of one another, each selected from H and a group C.sub.m H.sub.2m+1, where m is at least 1.

A cured resin product comprising a thermoset resin (A) and a thermoplastic resin (C), wherein the cured resin product comprises at least a phase (1) in which the thermoplastics resin (C) is at least a major constituent;

• and a phase (2) in which the thermoset resin (A) is at least a major constituent, each of said phases (1) and (2) is separate from the other and has a three dimensionally continuous structure, and phase (1) contains a silicon containing compound and has a concentration of elemental silicon higher than that in any other phase, wherein the cured resin product is formed from a thermoplastics resin (C) comprising a copolymer selected from the group consisting of block and graft copolymers, which copolymer has a siloxane molecular chain originally incompatible with, and a molecular chain selected from the group consisting of polyimide, polyamide and polyether molecular chains compatible with, the thermoset resin (A), wherein the thermoplastics resin (C) is selected from the group consisting of polyimides and polyamides each having a siloxane molecular chain.

A cured resin product comprising a thermoset resin (A) and a thermoplastic resin (C), wherein the cured resin product comprises at least a phase (1) in which the thermoplastics resin (C) is at least a major constituent;

• and a phase 2) in which the thermoset resin (A) is at least a major constituent, each of said phases (1) and (2) is separate from the other and has a three dimensionally essentially continuous structure, and the cured resin product additionally includes regions where one of the phases (1) and (2) essentially surrounds the other, wherein the cured resin product is formed from a thermoplastics resin (C) comprising a Copolymer selected from the group consisting of block and graft copolymers, which copolymer has a siloxane molecular chain originally incompatible with, and a molecular chain selected from the group consisting of polyimide, polyamide and polyether molecular chains compatible with, the thermoset resin (A), wherein the thermoplastics resin (C) is selected from the group consisting of polyimides and polyamides each having a siloxane molecular chain.

A cured resin product having a thermoset resin (A) and a thermoplastic resin (C), wherein the cured resin product is formed from a thermoplastics resin (C) comprising a copolymer selected from the group consisting of block and graft copolymers, which copolymer has a siloxane molecular chain originally incompatible with, and a molecular chain selected from the group consisting of polyimide, polyamide and polyether molecular chains compatible with, the thermoset resin A);

• wherein said cured resin product has a strain energy release rate (GIC) of at least 400 J/m.sup.2, a flexural modulus of at least 300 Kg/mm.sup.2, a glass transition temperature (Tg) of at least 120.degree. C., at least two phases, each of which phases has a three dimensionally continuous structure, and one of which phases contains a silicon containing compound and has a concentration of elemental silicon higher than in any other phase, wherein the thermoplastics resin (C) is selected from the group consisting of polyimides and polyamides each having a siloxane molecular chain.

A cured resin product comprising a thermoset resin component (A) and a thermoplastics resin component (C), Said thermoplastics resin and thermoset resin component (C) and (A) being present at least partly in respective phases (1) and (2), each of said phases being continuous and one of said phases (1) and (2) contains a silicon containing compound and has a concentration of elemental silicon higher than that in any other phase, wherein the cured resin product is formed from a thermoplastics resin (C) comprising a copolymer selected from the group consisting of block and graft copolymers, which copolymer has a siloxane molecular chain originally incompatible with, and a molecular chain selected from the group consisting of polyimide, polyamide and polyether molecular chains compatible with, the thermoset resin (A), wherein the thermoplastics resin (C) is selected from the group consisting of polyimides and polyamides each having a siloxane molecular chain.

A resin composition comprising a thermosetting resin (A), a curing agent (B) and a thermoplastics resin (C), which is soluble in the resin (A), wherein the thermoplastics resin (C) is a copolymer selected from the group consisting of block copolymers and graft copolymers each comprising a molecular chain compatible with, and a molecular chain incompatible with, at least one of the thermosetting resin (A) and curing agent (B), wherein the thermoplastics resin (C) is selected from the group consisting of polyimides and polyamides each having a siloxane molecular chain.