EPOXY RESIN COMPOSITION, PREPREG, METAL-CLAD LAMINATE, AND PRINTED WIRING BOARD
Disclosed is an epoxy resin composition comprising: (A) a polymerized compound including, as structural components, phosphaphenanthrene and at least one constituent selected from a structural unit of a phenolic novolak polymer and a structural unit of a phenolic novolak polymer in which a hydrogen atom of a phenolic hydroxyl group is substituted by phosphaphenanthrene; (B) an epoxy resin having two or more epoxy groups in a molecule; and (C) a curing agent that cures the epoxy resin.
1 . An epoxy resin composition comprising:
(A) a polymerized compound including, as structural components, phosphaphenanthrene and at least one constituent selected from a structural unit of a phenolic novolak polymer and a structural unit of a phenolic novolak polymer in which a hydrogen atom of a phenolic hydroxyl group is substituted by phosphaphenanthrene;
(B) an epoxy resin having two or more epoxy groups in a molecule; and
(C) a curing agent that cures the epoxy resin.
2 . The epoxy resin composition according to claim 1 , wherein the curing agent is a phenolic novolak curing agent with a softening point equal to or lower than 120° C.
3 . The epoxy resin composition according to claim 1 , wherein the curing agent is a phenolic novolak curing agent with a softening point equal to or lower than 105° C.
4 . The epoxy resin composition according to claim 2 , wherein a phenolic novolak curing agent with a softening point equal to or lower than 105° C. and a phenolic novolak curing agent with a softening point of 105° C. to 120° C. are used together as the curing agent.
5 . The epoxy resin composition according to claim 1 , wherein the curing agent is an amine curing agent.
6 . The epoxy resin composition according to claim 1 , wherein the phosphaphenanthrene is 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide or a derivative thereof.
7 . The epoxy resin composition according to claim 6 , wherein the polymerized compound (A) is a polymerized compound represented by Chemical Formula (I) below:
(in the formula, m is 0 to 3; n is 0 to 6; however, m and n are not 0 at the same time).
8 . The epoxy resin composition according to claim 1 , wherein a phosphorus concentration in the polymerized compound (A) is 10 wt % to 11 wt %.
9 . The epoxy resin composition according to claim 1 , further comprising an imidazole and a metal soap as curing accelerators.
10 . The epoxy resin composition according to claim 1 , further comprising 1 part by weight to 10 parts by weight of a condensed phosphoric acid ester as a flame retardant.
11 . A prepreg obtained by impregnating a fibrous substrate with the epoxy resin composition according to claim 1 .
12 . A metal-clad laminate obtained by laminating a metal foil on the prepreg according to claim 11 and performing hot-press molding.
13 . A printed wiring board obtained by partially removing the metal foil located on a surface of the metal-clad laminate according to claim 12 to form a circuit.