| 摘要 |
<p>1502722 Stabilized silica sols KOWA CHEMICAL INDUSTRY Ltd 18 March 1976 [20 March 1975 11 Nov 1975] 10875/76 Heading C1A [Also in Divisions C3 and C4] A composition comprises a silica sol, i.e. a colloidal dispersion of polymerized silica in a medium consisting mainly of water, together with (1) at least 5 parts by wt. of a dihydric alcohol containing at least 3 carbon atoms and (2) at least 2 parts by wt. of a water-soluble melamine resin, the proportions being based on 100 parts by wt. of sol, the diol may be propylene glycol, trimethylene glycol or triethylene glycol, and the melamine resin is preferably a methyl etherified melamine-formaldehyde precondensate. The composition may also contain a further synthetic resin, e.g. 10-35 parts by wt. of an emulsion polymer of vinyl acetate, vinyl propionate, vinyl sebacate and acrylic, methacrylic, fumaric, crotonic, maleic and itaconic acid or esters thereof. Coating compositions comprise 1 part of the above sol composition together with 2-20 parts by wt. of pigments, aggregates or fillers.</p> |
