Thermally conductive composition and a production method of a thermal conductive component using the composition

A thermally conductive composition comprising:

• a component (A) that is a diorganopolysiloxane having an alkenyl group bonded to a silicon atom;
• a component (B) that is a diorganopolysiloxane having a hydrogen atom bonded to a silicon atom;
• a component (C) that is expandable graphite;
• a component (D) that is a thermally conductive filler;
• and
• a component (E) that is an addition reaction catalyst,
• an organosilicon compound or an organosiloxane (also referred to as a silane coupling agent) that produces silanols by hydrolysis and a condensation catalyst,
• wherein the content of such silane coupling agent is used in an amount of one to three times as calculated by the following expression:
• Required amount (g) of silane coupling agent=Weight (g) of filler×Specific surface area (m2/g)/minimal covering area specific to silane coupling agent (m2/g),
• wherein
• a content of the component (C) is 0.5 parts by mass or more and 3 parts by mass or less relative to 100 parts by mass of a total amount of the components (A) and (B), and
• wherein an expansion rate (volume after high temperature exposure/volume before high temperature exposure) of a thermally conductive member obtained by curing the thermally conductive composition is 1.1 or less, and
• a content of the component (D) is 300 parts by mass or more and 2,000 parts by mass or less relative to 100 parts by mass of the total amount of the components (A) and (B).