| 摘要 |
<p>A method of making a gel composition comprises sequentially : (i) combining 15-30 wt% of silicone polyether and a cyclic methyl-siloxane of formula {(CH3)2SiO}p (I), or linear methyl-siloxane of formula (CH3)3SiO{(CH3)2SiO}qSi(CH3)3 (II), where p = 3-6; q = 0-5; (ii) mixing the components; (iii) adding water to the mixture such that the methyl-siloxane and water are in proportions of 40:60-80:20 by wt; and (iv) mixing the mixture until a clear gel is formed. The gel has a viscosity of 700,000 poise at an applied shear stress of 2,500 dyne/cm2 which decreases to 10,000 poise at an applied shear stress of 15,000 dyne/cm2. The silicone polyether is of formulae: (R1)3Si-O-[(R1)2Si-O]x-[R1R2Si-O]y-Si(R1)3 (III) R2(R1)2Si-O-[(R1)2Si-O]x-[R1R2Si-O]z-SiR2(R1)2 (IV) or (V), where R1 = 1-6C alkyl; R2 = -(CH2)aO(C2H4O)b(C3H6O)cR3; R3 = H, Me or acyl x = 0-3; y = 1-3; z = 0-2; m = 3-5; n = at least 1; a = 3-6; b = 13-24; c = 0-5. A Also claimed are: (1) a gel prepared according to the method and having a composition defined by and within a shaded area depicted in Fig. 1; (2) a gel having the composition defined by and within the shaded area depicted in the annexed sole figure 1, the gel being prepared as above and R1, R2, R3 and x, y, z, n, a, and c are as defined above and b = 10-30; and (3) a gel composition as above containing 15-30 wt% of the silicone polyether and the remainder methyl-siloxane and water.</p> |
