Silica-Containing Silicone Resin Composition and Its Molded Product
The present invention relates to a silica-containing silicone resin composition which provides high heat resistance, high transparency, and high dimension stability, and thus can be suitably used for optical applications such as a lens, an optical disc, an optical fiber, and a substrate for a flat panel display, or for a window material for an automobile and the like. The silica-containing silicone resin composition is obtained by incorporating 1 to 70 wt % of silica fine particles in a silicone resin composition, which is formulated with a cage type silicone resin mainly constituted of a polyorganosilsesquioxane represented by [RSiO 3/2 ] n (where R is an organic functional group containing a (meth)acryloyl group and n is 8, 10, or 12), and containing a cage type structure in its constitutional unit; and an unsaturated compound containing at least one unsaturated group represented by —R 3 —CR 4 ═CH 2 or —CR 4 ═CH 2 , (where R 3 represents an alkylene group, an alkylidene group, or a —OCO— group, and R 4 represents hydrogen or an alkyl group in a molecule), and capable of undergoing radical copolymerization with the silicone resin at a weight ratio of 1:99 to 99:1.
1 . A silica-containing silicone resin composition, characterized by containing 5 to 70 wt % of silica fine particles having an average particle size of 1 to 100 nm in a silicone resin composition, which is formulated with a cage type silicone resin mainly constituted of a polyorganosilsesquioxane represented by the general formula (1)
[RSiO 3/2 ] n (1)
where R is an organic functional group containing a (meth)acryloyl group and n is 8, 10, or 12; and containing a cage type structure in its constitutional unit; and
an unsaturated compound containing at least two unsaturated group represented by —R 3 —CR 4 ═CH 2 or —CR 4 ═CH 2 ,
where R 3 represents an alkylene group an alkylidene group, or a —OCO— group, and R 4 represents hydrogen or an alkyl group; in a molecule, and capable of undergoing radical copolymerization with the silicone resin at a weight ratio of 10:90 to 80:20.
2 . A silica-containing silicone resin composition according to claim 1 , wherein the silicone resin, which is prepared by subjecting a silicone compound represented by the general formula (3)
RSiX 3 (3)
where R is an organic functional group containing a (meth)acryloyl group and X represents a hydrolyzable group; to hydrolysis and partial condensation in the presence of a polar solvent and a basic catalyst, and further by subjecting the obtained hydrolysis product to recondensation in the presence of a nonpolar solvent and a basic catalyst, contains the same number of silicone atoms and (meth)acryloyl groups in the molecule and has a cage type structure.
3 . A silica-containing silicone resin composition according to claim 1 or 2 , wherein the unsaturated compound which is capable of undergoing radical copolymerization includes an unsaturated compound having a hydroxyl group represented by the general formula (4):
where R is an organic functional group containing a (meth)acryloyl group, X represents an organic functional group containing hydrogen or (meth)acryloyl group, and n is an integer of 0 or 1.
4 . A silica-containing silicone resin composition according to claim 1 , wherein the silica fine particle is treated with a silane compound of 0.1 to 80 wt %.
5 . A silica-containing silicone resin composition according to claim 4 , wherein the silane compound is represented by the general formula (5):
R m SiA n X 4-m-n (5)
where R is an organic functional group containing a (meth)acryloyl group, A is an alkyl group, X is an alkoxyl group or a halogen atom, m and n satisfy an integer in which m+n is 1 to 3, m is an integer of 0 or 1, and n is an integer of 0 to 3.
6 . A silica-containing silicone resin copolymer, which is obtained by subjecting the silica-containing silicone resin composition according to claim 1 to radical copolymerization.
7 . A resin molded article, which is obtained by subjecting the silica-containing silicone resin composition according to claim 1 to radical copolymerization.
8 . A resin molded article according to claim 7 , wherein the resin molded article comprises a coefficient of linear expansion of 40 ppm/K or less, a total light transmittance of 85% or more, and a glass transition temperature of 300° C. or more.
9 . A method of producing a resin molded article, comprising subjecting the silica-containing silicone resin composition according to claim 1 to radical copolymerization by heating or irradiation with energy rays.