Curable heat radiation composition

Abstract

The present invention relates to a curable heat radiation composition which includes two types of fillers with different compressive breaking strengths (except when the two types of fillers are the same substance) and a thermosetting resin, the compressive breaking strength ratio of the two types of fillers [compressive breaking strength of a filler (A) with a higher compressive breaking strength/compressive breaking strength of a filler (B) with a lower compressive breaking strength] being 5 to 1,500, the compressive breaking strength of the filler (A) being 100 to 1,500 MPa, and the compressive breaking strength of the filler (B) being 1.0 to 20 MPa, an adhesive sheet using the composition and a method for producing the same. An aluminum nitride is preferable as the filler (A) and hexagonal boron nitride agglomerated particles are preferable as the filler (B).

1 . A curable heat radiation composition, comprising two kinds of fillers having different compressive breaking strengths (provided that the case where the two kinds of fillers are the same substance is excluded), and a thermosetting resin (C), wherein a compressive breaking strength ratio between the two kinds of fillers [compressive breaking strength of a filler (A) having a higher compressive breaking strength/compressive breaking strength of a filler (B) having a lower compressive breaking strength] is from 5 to 1,500. 
     
     
         2 . The curable heat radiation composition according to  claim 1 , wherein the compressive breaking strength of the filler (A) having a higher compressive breaking strength is from 100 to 1,500 MPa, and the compressive breaking strength of the filler (B) having a lower compressive breaking strength is from 1.0 to 20 MPa. 
     
     
         3 . The curable heat radiation composition according to  claim 2 , wherein the filler (A) is aluminum nitride or alumina. 
     
     
         4 . The curable heat radiation composition according to  claim 2 , wherein the filler (B) is a hexagonal boron nitride agglomerated particle. 
     
     
         5 . The curable heat radiation composition according to  claim 1 , further including another inorganic filler in addition to the two kinds of fillers. 
     
     
         6 . The curable heat radiation composition according to  claim 5 , wherein the other inorganic filler is selected from aluminum hydroxide, fumed silica, and titanium oxide. 
     
     
         7 . The curable heat radiation composition according to  claim 1 , wherein the total content of the filler (A) having a higher compressive breaking strength and the filler (B) having a lower compressive breaking strength is from 50 to 95 mass %; or the total content of the filler (A) having a higher compressive breaking strength, the filler (B) having a lower compressive breaking strength, and the other inorganic filler is from 50 to 95 mass %; and the mass ratio [(A)/(B)] of the filler (A) having a higher compressive breaking strength to the filler (B) having a lower compressive breaking strength falls within the range of from 0.1 to 10. 
     
     
         8 . The curable heat radiation composition according to  claim 1 , further including a thermoplastic resin (D), wherein the content of the thermosetting resin (C) is from 70 to 95 parts by mass with respect to a total of 100 parts by mass of the thermosetting resin (C) and the thermoplastic resin (D). 
     
     
         9 . The curable heat radiation composition according to  claim 8 , wherein the thermosetting resin (C) contains a first thermosetting resin (C-1) having three or more reactive groups of at least one kind selected from an epoxy group and a (meth)acryloyl group in a molecule thereof, having a molecular weight per reactive group of less than 200, and having a number-average molecular weight of less than 1,000. 
     
     
         10 . The curable heat radiation composition according to  claim 8 , wherein the thermoplastic resin (D) contains at least one kind selected from a polyvinyl butyral resin and a polyester resin. 
     
     
         11 . The curable heat radiation composition according to  claim 1 , further containing a solvent. 
     
     
         12 . An adhesive sheet, comprising a supporting film, a covering film, and a film formed of the curable heat radiation resin composition according to  claim 1 , the film being formed between the supporting film and the covering film. 
     
     
         13 . A production method for an adhesive sheet, comprising applying the curable heat radiation resin composition according to  claim 1  to a supporting film, covering a part or the entirety of the applied surface with a covering film to provide a laminate, and heating and pressing the laminate with a roll press. 
     
     
         14 . A production method for an adhesive sheet, comprising applying the curable heat radiation resin composition according to  claim 1  to each of two supporting films, attaching the applied surface of one of the supporting films and the applied surface of the other supporting film to each other to provide a laminate, and heating and pressing the laminate with a roll press. 
     
     
         15 . A heat radiation cured product, which is obtained by heating and molding the curable heat radiation composition according to  claim 1  at a temperature in the range of from 70 to 200° C. and a pressure of from 1 to 100 MPa; and has a void content of 5% or less and a heat conductivity in its thickness direction of 10 W/m·K or more. 
     
     
         16 . A heat radiation cured product, which is obtained by heating and molding a laminate obtained by laminating a base material on an adhesive sheet obtained by the production method according to  claim 13  at a temperature in the range of from 70 to 200° C. and a pressure of from 0.1 to 10 MPa, and has a void content of 5% or less and a heat conductivity in its thickness direction of 10 W/m·K or more.