| 摘要 |
PURPOSE: A silicone rubber admixture containing hydrophobic silica and organopolysiloxane and its use are provided, wherein the silicone rubber admixture shows very high whiteness. CONSTITUTION: The silicone rubber admixture comprises 0.5-60 wt% of hydrophobic silica and 30-99.5 wt% of organopolysiloxane represented by ZnSiR3-n-O-(SiR2O)x-SiR3-n-Zn, wherein the hydrophobic silica has a carbon content above 3.1%, a methanol wetting above 60%, a reflectivity above 94%, a BET/CTAB ratio above 1 and below 3, a DBP absorption below 230 g/100 g, a BET surface area of 50-100 m2/g, a CTAB surface area above 30 m¬2/g, a degree of steam absorption below 1.3 at 20 deg.C and 30 Ah, and degree of steam absorption below 1.7 at 30 deg.C and 70 Ah. In the formula, R's are identical or different one another and are an alkyl, alkoxy, aryl or alkenyl group of C1-C50 unsubstituted or substituted with O, S, F, Cl, Br or I, OH, hydride, and/or a polystyrene, poly(vinyl acetate), polyacrylate, polymethacrylate and polyacrylonitrile having 50-10,000 repeating units; Z's are identical or different one another and are H, OH, Cl, Br, amino, aminoxy, alkenyloxy, aryloxy or phosphate (the number of carbons of free radical is 20 or less); n is 1-3; and n is 100-15,000.
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