Patent ID: 6046283
Filing Date: 2000-04-04
Classification: C08G,C08L

Abstract:
A rubber-modified rigid silicone resin comprising a copolymerized reaction product of:(A) an organosilicon composition selected from the group consisting of:(I) an organosilicone resin consisting essentially of silsesquioxane units and of the empirical formulaR.sup.1.sub.a R.sup.2.sub.b R.sup.3.sub.c SiO.sub.(4-a-b-c)/2wherein: a is a positive numerical value, b and c are zero or positive numerical values with the proviso that 0.8.ltoreq.(a+b+c).ltoreq.1.6, R.sup.1, R.sup.2 and R.sup.3 are monovalent radicals independently selected from the group consisting of hydrogen, hydroxyl, alkyl, alkenyl, alkoxy, oximo, alkyloximo, aryloximo, aryl, alkylepoxide, arylepoxide, alkylcarboxyl, arylcarboxyl, alkylether, arylether, alkylamide, arylamide, alkyl amino and arylamino radicals; and(II) hydrolyzable precursors of (I); and(III) an hydrolyzate formed from (II);(B1) a first silicone rubber of the empirical formula:(R.sup.4.sub.(3-p) R.sup.5.sub.p SiO.sub.1/2)(R.sup.4.sub.2 SiO.sub.2/2).sub.x -{(R.sup.4.sub.(2-q) R.sup.5.sub.q SiO.sub.2/2)(R.sup.4.sub.2 SiO.sub.2/2).sub.x }.sub.y (R.sup.4.sub.(3-p) R.sup.5.sub.p SiO.sub.1/2)wherein each R.sup.4 is a monovalent radical independently selected from the group consisting of alkyl and aryl radicals, each R.sup.5 is a monovalent radical independently selected from the group consisting of hydrogen, hydroxyl, alkenyl, alkoxy, oximo, alkyloximo, aryloximo, alkylepoxide, arylepoxide, alkylcarboxyl, arylcarboxyl, alkylamide, arylamide, aklyl amino and arylamino radicals, p is 1, 2 or 3, q is 1 or 2, x ranges from 6 to 100, and y ranges from zero to 10; and(B2) a second silicone rubber of the empirical formula(R.sup.4.sub.(3-p) R.sup.5.sub.p SiO.sub.1/2)(R.sup.4.sub.2 SiO.sub.2/2).sub.w (R.sup.4.sub.(3-p) R.sup.5.sub.p SiO.sub.1/2)wherein R4, R5 and p are as defined above and w ranges from about 200 to about 1,000;said organosilicon composition (A) and said first and second silicone rubbers (B1) and (B2) being present in relative quantities such that said rubber-modified silicone resin has a Young's modulus of at least 6.9.times.10.sup.8 Pa.