| 摘要 |
Foam suppressant emulsion based on organofunctionally modified polysiloxanes is obtd. by mixing (a) 0-90 pts.wt. organopolysiloxane of formula (I), (b) 0-90 pts.wt. organopolysiloxane of formula (II), (c) 0-90 pts.wt. organopolysiloxane of formula (III) and (d) 0-15 pts.wt. finely divided silica, stirring this mixt. (which must contain 10-90 pts.wt. a+b+c) into a mixt. of (e) 5-85 pts.wt. organopolysiloxane of formula (IV) and (f) 5-50 pts.wt. water using a low-shear stirrer, to give a stock emulsion which is diluted to the required concn. immediately or just before use. In (a) (formula I), R1 = 1-8C alkyl or -Z-(CnH2nO)mR2 (with R2 = H or 1-8C alkyl; Z = -O-, -(CH2)p-O- or -CH2-CHMe-CH2-O (with p = 2 or 3); n = 2.7-4.0; m = 5-130); a = 4-1500; b = 0-100; c = 0-50. In (b) formula (II) = formula (I) with R1 = OH or 1-4C alkoxy; a, b, c as in (I). In (e), formula (IV) = formula (I) with R1 = 1-8C alkyl or -Z-(CqH2qO)r-R2 (gp. R) (with R2 and Z as above; q = 2.0-2.7; r = 5-120); at least one gp. R1 = R; a = 4-200; b = 0-100; c = 0-50. In (c) (III): R5 = 1-4C alkyl (at least 90% of these gps. = Me); x = 2.6-3.0; y = 8-80; w = 7-50; z = 1.5-10.
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