| 摘要 |
1,155,523. Organically - modified silica. DEUTSCHE GOLD-UND SILBER-SCHEIDEANSTALT. 16 June, 1967 [18 June, 1966], No. 27962/67. Heading C1A. Finely-divided organically modified silica is precipitated, preferably at 50-90‹ C., from a silicate solution, e.g. water glass, by an inorganic or organic acid in the presence of one or more water-soluble organic polymers capable of undergoing modification of their properties by chemical reactions and of combination with silica, e.g. polyvinyl alcohol, polyethylene imine, polyacrolein, polymethacrylic acid, polyethylene oxide, polyvinyl pyrrolidone, polyvinyl-3- methyl pyrrolidone, vinyl pyrrolidone/vinyl acetate copolymers, polyacrylamide. The polymer(s) may be dissolved in the reaction mixture before precipitation or gradually added thereto during precipitation; in some cases a pure silica core may be formed around an organicallymodified shell. The polymers may be caused to undergo organic reactions, e.g. substitution, addition, salt or complex formation, or may be refined by substantive, reactive or leuco dyes at any time after silica is first formed (although not necessarily precipitated): examples of such reactions are given. |
