| 摘要 |
A silica free curable composition comprising: A) a stable dispersion in an aqueous medium of a First Polymer having a weight average molecular weight of at least 50,000, which is insoluble in water and which contains silane groups of formula (1); <CHEM> in which a is 0 to 2, R<1> is C1-6 alkyl, and R is OH or a hydrolysable group, the groups of formula (1) contributing from 0.05 to 2% by weight of silicon to the weight of the First Polymer and B) a solution or dispersion of a Second Polymer which has a number average moecular weight of MWt between 1000 and 20,000, and which contains at least two silane groups of formula (1), the groups of Formula (1) contributing from 0.1 to 8% by weight of silicon to the weight of the Second Polymer, and also comprising covalently bonded acid groups in an amount so as to render the Second Polymer soluble or self-dispersible in the aqueous medium, the ratio of the Polymer (A) to the Polymer (B) being in the range 40:1 to 1:4. |
