Heat-conducting foam sheet for electronic instruments and heat-conducting laminate for electronic instruments

Abstract

Provided is a heat conductive foam sheet for electronic equipment sufficiently thin and flexible to be suitably used in the interior of electronic equipment and excellent in heat conductivity. A heat conductive foam sheet for electronic equipment containing a heat conductor in an elastomer resin portion constituting the foam sheet, in which the content of the heat conductor relative to 100 parts by mass of the elastomer resin is 100 to 500 parts by mass, the 25% compressive strength of the foam sheet is 200 kPa or less and the thickness thereof is 0.05 to 1 mm.

1 . A heat conductive foam sheet for electronic equipment containing a heat conductor in an elastomer resin portion constituting the foam sheet, wherein the content of the heat conductor relative to 100 parts by mass of the elastomer resin is 100 to 500 parts by mass, the 25% compressive strength of the foam sheet is 200 kPa or less and the thickness thereof is 0.05 to 1 mm. 
     
     
         2 . The heat conductive foam sheet for electronic equipment according to  claim 1 , wherein the heat conductor is at least one selected from the group consisting of aluminum oxide, magnesium oxide, boron nitride, talc, aluminum nitride, graphite and graphene. 
     
     
         3 . The heat conductive foam sheet for electronic equipment according to  claim 1 , wherein the heat conductivity of the foam sheet is 0.3 to 10 W/m·K. 
     
     
         4 . The heat conductive foam sheet for electronic equipment according  claim 1 , wherein the expansion ratio of the foam sheet is 1.5 to 5. 
     
     
         5 . The heat conductive foam sheet for electronic equipment according to  claim 1 , wherein the elastomer resin is an acrylonitrile butadiene rubber or a liquid-state acrylonitrile butadiene rubber, and an ethylene-propylene-diene rubber or a liquid-state ethylene-propylene-diene rubber and a mixture thereof. 
     
     
         6 . The heat conductive foam sheet for electronic equipment according to  claim 1 , wherein the elastomer resin contains a liquid elastomer in an amount of 10 mass % or more, and the 50% compressive strength of the foam sheet is 200 kPa or less. 
     
     
         7 . The heat conductive foam sheet for electronic equipment according to  claim 1 , wherein the elastomer resin is a butyl rubber or an ethylene-propylene rubber. 
     
     
         8 . The heat conductive foam sheet for electronic equipment according to  claim 1 , wherein a dielectric constant of the foam sheet is 4 or less. 
     
     
         9 . A heat conductive foam sheet for electronic equipment containing a heat conductor in an elastomer resin portion constituting the foam sheet, wherein the heat conductor has a scale-like shape defined by a major axis of 1 to 300 μm, a minor axis of 1 to 300 μm and a ratio of the major axis to thickness (major axis/thickness) of 2 to 500 and/or a fibrous shape defined by a diameter of 0.01 to 50 μm and a ratio of length to the diameter (length/diameter) of 5 to 30,000; and the 25% compressive strength of the foam sheet is 200 kPa or less and the thickness thereof is 0.05 to 1 mm. 
     
     
         10 . The heat conductive foam sheet for electronic equipment according to  claim 9 , wherein the heat conductor is at least one selected from the group consisting of boron nitride, talc, aluminum nitride, graphite, a carbon nanotube and a carbon fiber 
     
     
         11 . The heat conductive foam sheet for electronic equipment according to  claim 9 , wherein the heat conductivity of the foam sheet is 0.3 to 10 W/m·K. 
     
     
         12 . The heat conductive foam sheet for electronic equipment according to  claim 9 , wherein the expansion ratio of the foam sheet is 1.5 to 5. 
     
     
         13 . The heat conductive foam sheet for electronic equipment according to  claim 9 , wherein the elastomer resin is an acrylonitrile butadiene rubber. 
     
     
         14 . The heat conductive foam sheet for electronic equipment according to  claim 9 , wherein the content of the heat conductor relative to 100 parts by mass of the elastomer resin is 100 to 500 parts by mass. 
     
     
         15 . A heat conductive laminate for electronic equipment, which has a heat conductive sheet having a heat conductivity of 200 W/m·K or more on at least one of the surfaces of a foam sheet having a 25% compressive strength of 200 kPa or less and a thickness of 0.05 to 1.0 mm; and which has a thickness of 0.08 to 1.50 mm. 
     
     
         16 . The heat conductive laminate for electronic equipment according to  claim 15 , wherein the elastomer resin constituting the foam sheet contains at least one heat conductive filler selected from the group consisting of aluminum oxide, magnesium oxide, boron nitride, talc and aluminum nitride. 
     
     
         17 . The heat conductive laminate for electronic equipment according to  claim 16 , wherein the content of the heat conductive filler relative to 100 parts by mass of the elastomer resin is 100 to 500 parts by mass. 
     
     
         18 . The heat conductive laminate for electronic equipment according to  claim 15 , wherein the expansion ratio of the foam sheet is 1.5 to 6. 
     
     
         19 . The heat conductive laminate for electronic equipment according to  claim 15 , wherein the heat conductive sheet is a sheet of one selected from copper, aluminum and graphite. 
     
     
         20 . The heat conductive laminate for electronic equipment according to  claim 15 , wherein the elastomer resin constituting the foam sheet is an acrylonitrile butadiene rubber or a linear low-density polyethylene.