Resin composition, prepreg, and laminate

Abstract

There are provided a resin composition for printed wiring boards that has a low coefficient of thermal expansion in a plane direction, has excellent heat resistance and drilling workability, and, at the same time, can retain a high level of flame retardance, a prepreg prepared using the resin composition, and a laminated sheet and a metal foil-laminated sheet prepared using the prepreg. The resin composition comprises (A) an inorganic filler that is a mixture composed of a hydromagnesite represented by formula (1): x MgCO 3 .y Mg(OH) 2 .z H 2 O  (1) wherein x:y:z is 4:1:4, 4:1:5, 4:1:6, 4:1:7, 3:1:3, or 3:1:4 and huntite; (B) an epoxy resin; and (C) a curing agent.

1 . A resin composition comprising:
 (A) an inorganic filler that is a mixture composed of a hydromagnesite represented by formula (1):
     x MgCO 3   .y Mg(OH) 2   .z H 2 O  (1)
 
   wherein x:y:z is 4:1:4, 4:1:5, 4:1:6, 4:1:7, 3:1:3, or 3:1:4 and huntite;   (B) an epoxy resin; and   (C) a curing agent.   
     
     
         2 . The resin composition according to  claim 1 , wherein the hydromagnesite represented by formula (1) is one represented by formula (2):
   4MgCO 3 .Mg(OH) 2 .4H 2 O  (2)
   
     
     
         3 . The resin composition according to  claim 1 , wherein the hydromagnesite:huntite weight ratio in the inorganic filler (A) is in the range of 10:90 to 45:55. 
     
     
         4 . The resin composition according to  claim 1 , wherein the curing agent (C) is at least one material selected from the group consisting of cyanate ester compounds, BT resins, and phenolic resins. 
     
     
         5 . The resin composition according to  claim 4 , wherein the cyanate ester compound is a naphthol aralkyl cyanate ester compound represented by formula (5): 
       
         
           
           
               
               
           
         
         wherein R 11  represents a hydrogen atom or a methyl group; and q is an integer of 1 or more, or 
         the BT resin is a resin produced using the naphthol aralkyl cyanate ester compound represented by formula (5) as a raw material. 
       
     
     
         6 . The resin composition according to  claim 4 , wherein the phenolic resin is at least one resin selected from the group consisting of naphthol aralkyl phenolic resins, biphenyl aralkyl phenolic resins, and naphthalene phenolic resins. 
     
     
         7 . The resin composition according to  claim 4 , wherein the phenolic resin is a naphthol aralkyl phenolic resin represented by formula (6): 
       
         
           
           
               
               
           
         
         wherein R represents a hydrogen atom or a methyl group; and n is an integer of 1 or more. 
       
     
     
         8 . The resin composition according to  claim 1 , wherein the epoxy resin (B) is at least one of phenol novolak epoxy resins and aralkyl novolak epoxy resins. 
     
     
         9 . The resin composition according to  claim 1 , wherein the epoxy resin (B) is an aralkyl novolak epoxy resin represented by formula (3): 
       
         
           
           
               
               
           
         
         wherein Ar 2 s, which may be the same or different, represent and Ar 2  represents or when present in plural which may be the same or different, represent an aryl group in which the substituent is a monocyclic or polycyclic aromatic hydrocarbon of a phenyl, naphthyl, or biphenyl group; Rxs, which may be the same or different, and Ry represents or when present in plural which may be the same or different, represent a hydrogen atom or an alkyl or aryl group; m is an integer of 1 to 5; n is an integer of 1 to 50; and G represents a glycidyl group. 
       
     
     
         10 . The resin composition according to  claim 1 , which further comprises a maleimide compound. 
     
     
         11 . The resin composition according to  claim 1 , which further comprises a silicone powder. 
     
     
         12 . The resin composition according to  claim 1 , wherein the mixing amount of the inorganic filler (A) is 5 to 250 parts by weight based on 100 parts by weight in total of the epoxy resin (B) and the curing agent (C). 
     
     
         13 . The resin composition according to  claim 1 , wherein the mixing amount of the epoxy resin (B) is 5 to 70 parts by weight based on 100 parts by weight in total of the epoxy resin (B) and the curing agent (C). 
     
     
         14 . A prepreg comprising: a base material; and a resin composition according to  claim 1  impregnated into or coated on the base material. 
     
     
         15 . A laminated sheet comprising a lamination-molded product of a prepreg according to  claim 14 . 
     
     
         16 . A metal foil-clad laminated sheet comprising a lamination-molded product of a prepreg according to  claim 14  and a metal foil provided on the prepreg.