Patent ID: 9365001
Filing Date: 2016-06-14
CPC Classification: B26D,B29C,B29D,B29K,B29L,C08G,C08J,C08K,C08L,H01L,Y10T

Claim Text:
1. A thermally conductive sheet produced by the following steps: extruding a thermally conductive composition containing a polymer, an anisotropic thermally conductive filler and another filler through an extruder, thereby extrusion molding an extrusion molded product in which the anisotropic thermally conductive filler is oriented along the extrusion direction; curing the extrusion molded product to form a cured object; and cutting the cured object in a direction perpendicular to the extrusion direction into a given thickness with an ultrasonic cutter, wherein the anisotropic thermally conductive filler is prepared as carbon fibers and has an average fiber length of 100 μm or more, the other filler is prepared as spherical alumina particles and has an average particle size in a range from 1 μm to 40 μm, the carbon fibers are oriented in the range from 0° to 5° with respect to the thickness direction of the thermally conductive sheet, a peripheral portion on a surface of the thermally conductive sheet has a slight stickiness that is higher than that of an inside portion on the surface of the thermally conductive sheet, the inside portion of the thermally conductive sheet being encompassed by the peripheral portion of the thermally conductive sheet, the thermally conductive sheet has a cut surface having a surface roughness Ra of 9.9 μm of less, the polymer is a silicone resin, the spherical alumina particles are contained in a range from 40 to 55% by volume; and the carbon fibers are contained in a range from 10 to 25% by volume.