Curable cage-type silicone copolymer and process for production thereof and curable resin composition comprising curable cage-type silicone copolymer and cured product thereof

1. A process for producing a cage-type curable silicone copolymer characterized by having a constituent unit represented by the following general formula (1):

Y—[Z—(O 1/2 —R 2 2 SiO 1/2 ) a —(R 1 SiO 3/2 ) n —(O 1/2 ) b ] m —Z—Y  (1)

wherein R 1 and R 2 each is a vinyl group, an alkyl group, a phenyl group, a (meth)acryloyl group, an allyl group, or an oxirane ring-containing group; the substituents selected for R 1 and R 2 may be identical with or different from one another and at least one of the substituents selected for R 1 contained in a molecule is a vinyl group, a (meth)acryloyl group, an allyl group, or an oxirane ring-containing group; a and b each is a number of 0-3 and satisfies the relationship 1≦a+b≦4 and n denotes a number of 8-14; in the case where n is an odd number, a and b are a combination of an even number and an odd number including 0; in the case where n is an even number, a and b are a combination of even numbers including 0; m denotes a number of 1-2,000; Z is a divalent group represented by the following general formula (2)

wherein R 3 is a hydrogen atom, a vinyl group, an alkyl group, a phenyl group, a (meth)acryloyl group, an allyl group, or an oxirane ring-containing group, the substituents selected for R 3 may be identical with or different from one another, and p denotes a number of 0-30; and Y is a monovalent group selected from the following general formulas (3) to (6)

[(R 4 O)R 2 2 SiO 1/2 ] a —[R 1 SiO 3/2 ] n —[O 1/2 ]—  (3)

[R 4 O 1/2 ] b —[R 1 SiO 3/2 ] n —[O 1/2 —R 2 2 SiO 1/2 ]—  (4)

(R 4 O 1/2 )—  (5)

(R 2 3 SiO 1/2 )—  (6)

wherein R 1 and R 2 each is a vinyl group, an alkyl group, a phenyl group, a (meth)acryloyl group, an allyl group, or an oxirane ring-containing group; the substituents selected for R 1 or R 2 may be identical with or different from one another; R 4 is selected from a hydrogen atom, a methyl group, and an ethyl group; a and b each is a number of 0-3 and n denotes a number of 8-14; in the case where n is an odd number, a and b each is independently 0 or 2; in the case where n is an even number, a and b each is independently 1 or 3: the said process comprising condensing a cage-type siloxane compound containing an alkoxyl group or silanol group represented by the following general formula (7)

[(R 4 O)R 2 2 SiO 1/2 ] a —[R 1 SiO 3/2 ] n —[O 1/2 R 4 ] b   (7)

wherein R 1 and R 2 each is selected from a vinyl group, an alkyl group, a phenyl group, a (meth)acryloyl group, an allyl group, and an oxirane ring-containing group; R 4 is selected from a hydrogen atom, a methyl group, and an ethyl group; the substituents selected for R 1 , R 2 , or R 4 may be identical with or different from one another and at least one of the substituents selected for R 1 contained in a molecule is a vinyl group, a (meth)acryloyl group, an allyl group, or an oxirane ring-containing group; a and b each is a number of 0-3 and satisfies the relationship 1≦a+b≦4; further, n is an integer of 8-14; in the case where n is an odd number, a and b are a combination of an even number and an odd number including 0; in the case where n is an even number, a and b are a combination of even numbers including 0 with a compound represented by the following compound (8)

wherein R 3 is a hydrogen atom, a vinyl group, an alkyl group, a phenyl group, a (meth)acryloyl group, an allyl group, or an oxirane ring-containing group; the substituents selected for R 3 may be identical with or different from one another; X is a hydroxyl group, a hydrogen atom, a chlorine atom, or an alkoxyl group; the substituents selected for X may be identical with or different from one another; further, p denotes a number of 0-30, and then condensing the said condensation reaction product with a compound represented by the following general formula (9)

R 2 3 Si—X  (9)

wherein R 2 is a hydrogen atom, a vinyl group, an alkyl group, a phenyl group, a (meth)acryloyl group, an allyl group, or an oxirane ring-containing group, the substituents selected for R 2 may be identical with or different from one another, and X is a hydroxyl group, a hydrogen atom, a chlorine atom, or an alkoxyl group,

wherein the process further comprises mixing a cage-type siloxane compound represented by the following general formula (19)

[R 1 SiO 3/2 ] n   (19)

wherein R 1 is selected from a vinyl group, an alkyl group, a phenyl group, a (meth)acryloyl group, an allyl group, and an oxirane ring-containing group, the substituents selected for R 1 may be identical with or different from one another, and n is an integer of 8-14; with a dialkoxysilane represented by the following general formula (20)

R 2 2 Si(OR 5 ) 2   (20)

wherein R 2 is selected from a vinyl group, an alkyl group, a phenyl group, a (meth)acryloyl group, an allyl group, and an oxirane ring-containing group, R 5 is selected from a methyl group and an ethyl group, and the substituents selected for R 2 or R 5 may be identical with or different from one another; at a molar ratio [R 1 SiO 3/2 ] n : R 2 2 Si(OR 5 ) 2 in the range of 1:0.5 to 1:2, and subjecting the mixture to addition reaction in a non-polar solvent in the presence of a basic catalyst to yield a cage-type siloxane compound containing an alkoxyl group represented by general formula (7).

2. A process for producing a curable cage-type silicone copolymer as described in claim 1 wherein 1 mole of a cage-type silsesquioxane compound containing an alkoxyl group or silanol group represented by general formula (7) is subjected to a condensation reaction with 0.5-10 moles of a compound represented by general formula (8).

3. A process for producing a curable cage-type silicone copolymer as described in claim 1 wherein 1 mole of a cage-type silsesquioxane compound containing an alkoxyl group or silanol group represented by general formula (7) is subjected to a condensation reaction with 0.5-10 moles of a compound represented by general formula (8) and with 2-100 moles of a compound represented by general formula (9).

4. A curable resin composition formed by incorporating a hydrosylilation catalyst or a radical initiator or both in the curable cage-type silicone copolymer obtained by the process described in claim 1 .

5. A curable resin composition as described in claim 4 wherein a hydrosylilatable compound having a hydrogen atom on at least one silicon atom or a compound having an unsaturated group in the molecule or both are further incorporated.

6. A molded article obtained by curing the curable resin composition described in claim 5 .

7. A process for producing a curable cage-type silicone copolymer as described in claim 1 wherein the product cage-type siloxane compound containing an alkoxyl group has a number average molecular weight M n in the range of 500-2,000 and a molecular weight distribution, weight average molecular weight M w /number average molecular weight M n , in the range of 1.0-2.0.

8. A process for producing a curable cage-type silicone copolymer as described in claim 1 , further comprising hydrolyzing the addition product in the presence of an acid catalyst or a basic catalyst to yield a cage-type siloxane compound containing a silanol group represented by general formula (7).

9. A process for producing a curable cage-type silicone copolymer as described in claim 8 wherein the product cage-type siloxane compound containing a silanol group has a number average molecular weight M n in the range of 500-2,000 and a molecular weight distribution, weight average molecular weight M w /number average molecular weight M n , in the range of 1.0-2.0.

10. A molded article obtained by curing the curable resin composition described in claim 5 .