Process for producing resin varnish containing semi-ipn composite, thermosetting resin and, provided using the same, resin varnish for printed wiring board, prepreg and metal-clad laminate

Abstract

A thermosetting resin varnish that includes a thermosetting resin composition of an uncured semi-IPN composite having compatibilized with one another (A) a polyphenylene ether, (B) a butadiene polymer which contains in the molecule thereof 40% or more of a 1,2-butadiene unit having a 1,2-vinyl group in the side chain thereof, and which is not chemically modified, and (C) a crosslinking agent; (D) an inorganic filler; and (E) a saturated thermoplastic elastomer. Also, a resin varnish for a printed circuit board, a prepreg, and a metal-clad laminate, using the thermosetting resin varnish.

1 . A thermosetting resin varnish comprising: a thermosetting resin composition of an uncured semi-IPN composite having compatibilized with one another (A) a polyphenylene ether, (B) a butadiene polymer which contains in the molecule thereof 40% or more of a 1,2-butadiene unit having a 1,2-vinyl group in the side chain thereof, and which is not chemically modified, and (C) a crosslinking agent; (D) an inorganic filler; and (E) a saturated thermoplastic elastomer. 
     
     
         2 . The thermosetting resin varnish according to  claim 1 , which has a viscosity of 10 to 300 mPa·s at 25° C. 
     
     
         3 . A resin varnish for printed circuit board, obtained by using the process for producing a thermosetting resin varnish according to  claim 1 . 
     
     
         4 . A prepreg obtained by impregnating a substrate with the thermosetting resin varnish according to  claim 1 , and then drying the resultant substrate at 60 to 200° C. 
     
     
         5 . A metal-clad laminate obtained by stacking one or more sheets of the prepreg according to  claim 4  on one another to prepare a stacked prepreg, disposing a metallic foil on one side or both sides of the stacked prepreg, and pressing them together while heating. 
     
     
         6 . A prepreg obtained by impregnating a substrate with the resin varnish for printed circuit board according to  claim 3 , and then drying the resultant substrate at 60 to 200° C. 
     
     
         7 . A metal-clad laminate obtained by stacking one or more sheets of the prepreg according to  claim 6  on one another to prepare a stacked prepreg, disposing a metallic foil on one side or both sides of the stacked prepreg, and pressing them together while heating.