| 摘要 |
1,221,796. Paper. DEUTSCHE GOLDUND SILBER-SCHEIDEANSTALT. 15 Jan., 1968 [17 Jan., 1967], No. 2117/68. Addition to 1,155,523. Heading D2B. [Also in Division C1] A paper filler having reactive groups capable of absorbing dyes by reaction therewith is prepared by precipitating a silicate of an alkalineeanth metal or of Al, Sc, Y or La from an aqueous alkali metal silicate solution in the presence of organic water-soluble polymer (see Division C1). The reactive groups in the filler can be cross-linked with a polyvalent reagent to improve the bonding between the paper fibres and the filler. The polymer may be polyvinyl alcohol, polyethylene urine, polyacrolein, polymethacrylic acid, polyethylene oxide, cationic or anionic starch, polyvinyl pyrrolidone, polyvinyl-3- methyl pyrrolidone, vinyl pyrrolidone/vinyl acetate copolymers, polyacrylamide, urea resin, melamine resin, may be dissolved in the reaction mixture before precipitation, or gradually added thereto during precipitation, or added in such a manner that a silicate core with an organically-modified shell is obtained. |
