| 摘要 |
Process for producing silicate-comprising polyols, which comprises the steps (i) admixing of an aqueous silica sol (K) having an average particle diameter of from 1 to 150 nm and a silica content, calculated as SiO2, of from 1 to 60% by weight and having a pH of from 1 to 6, based on the SiO2 content used, with a 0.1- to 20-fold amount (based on the amount of water) of at least one organic solvent (L) selected from the group consisting of methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, 2-methyl-2-propanol, 1-chloro-2-propanol, cyclopentanol, cyclohexanol, 1,4-dioxane, tetrahydrofuran, 1-methoxy-2-propanol, 1-ethoxy-2-propanol, 2-ethoxyethanol, 2-methyl-2-propanol, 2-methoxyethanol, dimethylformamide, acetonitrile, dimethyl sulfoxide and acetone, methyl ethyl ketone and ethylacetate, and (ii) admixing of the resulting mixture with a polyol, (iii) at least partial removal of the water and organic solvent (L) by distillation, (iv) admixing with at least one compound (S) which has at least one at least monoalkoxylated silyl group and at least an alkyl, cycloalkyl or aryl substituent, which may contain heteroatoms, wherein this substituent optionally contains a group which is reactive toward an alcohol, an amine or an isocyanate, in an amount of from 0.1 to 20 μmol of (S) per m2 of surface area of (K), with the steps (i), (ii) and (iv) being able to be carried out simultaneously or in succession in any order, (v) optionally adjustment of the pH of the silica-comprising polyol to a value of from 7 to 12 by addition of a strongly basic compound, with step (v) also being able to be carried out between steps (iii) and (iv). |
