SURFACE-TREATED FILLER, METHOD FOR PRODUCING SURFACE-TREATED FILLER, AND HEAT CONDUCTING COMPOSITION

1 . A surface-treated filler obtained by surface-treating a surface of a filler with α-butyl-ω-(2-trimethoxysilylethyl)polydimethylsiloxane having a weight average molecular weight of 500 to 5,000, wherein

an adhesion percentage of the α-butyl-ω-(2-trimethoxysilylethyl)polydimethylsiloxane to the filler is from 20.0 to 50.0% by mass.

2 . The surface-treated filler according to claim 1 , wherein the filler is at least one selected from the group consisting of at least one metal selected from the group consisting of silver, copper, and aluminum, silicon, a metal oxide, a nitride, and a composite oxide.

3 . The surface-treated filler according to claim 1 , wherein the filler has a cumulative volume-based 50% particle size of from 0.1 to 30 μm.

4 . A method for producing a surface-treated filler, comprising:

a treatment liquid production step of producing a treatment liquid comprising α-butyl-ω-(2-trimethoxysilylethyl)polydimethylsiloxane having a weight average molecular weight of from 500 to 5,000, an alcohol, and water;

a pre-treatment step of mixing a filler and the treatment liquid; and

a heat treatment step of heat-treating the mixture obtained in the pre-treatment step at a temperature of from 140 to 180° C.

5 . The method for producing a surface-treated filler according to claim 4 , comprising a drying step of drying the mixture obtained in the pre-treatment step before the heat treatment step.

6 . The method for producing a surface-treated filler according to claim 4 , wherein the heat treatment is performed for from 2 to 6 hours.

7 . A heat conducting composition comprising:

a polymer component; and

a filler, wherein

the filler comprises the surface-treated filler according to claim 1 , and

a content of the polymer component is from 2 to 15% by mass and a content of the filler is from 85 to 98% by mass based on the total amount of the heat conducting composition.

8 . The heat conducting composition according to claim 7 , wherein a content of the surface-treated filler comprised in the filler is from 40 to 60% by mass.

9 . The heat conducting composition according to claim 7 , wherein the polymer component is at least one selected from the group consisting of a thermosetting resin, an elastomer, and an oil.

10 . A cured product of the heat conducting composition according to claim 7 .

11 . The cured product of the heat conducting composition according to claim 10 , wherein the cured product has a thermal conductivity of 4.0 W/m·K or more.