Method for producing prepreg and laminate

Abstract

This invention relates to a method for storing a naphthol aralkyl type cyanate ester resin solution, which is difficult to precipitate due to long term storage in a solution state, and particularly relates to a method for storing a naphthol aralkyl type cyanate ester resin solution (AB), which comprises: preparing (i) a naphthol aralkyl type cyanate ester resin solution (AB) comprising a naphthol aralkyl type cyanate ester resin (A), a maleimide compound (B) and a solvent, (ii) a naphthol aralkyl type cyanate ester resin solution (AB) comprising a prepolymer of a naphthol aralkyl type cyanate ester resin (A), a maleimide compound (B) and a solvent, or (iii) a naphthol aralkyl type cyanate ester resin solution (AB) comprising a prepolymer of a naphthol aralkyl type cyanate ester resin (A) and a maleimide compound (B), and a solvent, and; storing the resin solution (AB).

What is claimed is: 
     
         1 . A method for producing a prepreg, which comprises:
 preparing a varnish comprising a naphthol aralkyl type cyanate ester resin solution (AB) stored by the method according to  claim 1 , a non-halogen epoxy resin (C), a silicone rubber powder (D) and an inorganic filler (E), and;   impregnating a substrate (F) with the varnish.   
     
     
         2 . A method for producing a prepreg according to  claim 1 , wherein the inorganic filler (E) is a molten silica. 
     
     
         3 . A method for producing a laminate, which comprises heat-molding a prepreg produced by the method according to  claim 1 . 
     
     
         4 . A method for producing a metal foil clad laminate, which comprises curing a laminate of a prepreg produced by the method according to  claim 1  and a metal foil.