| 摘要 |
<p>1449002 Polyol silicate coating compositions G D MCLEOD 28 Aug 1973 [28 Aug 1972] 40548/73 Heading C3T A coating composition comprises (1) the product of reaction of (i) an organic silicate in which the organic groups are C 1-6 alkyl, hydroxyalkyl, alkoxyalkyl, or hydroxyalkoxyalkyl groups with (ii) an aliphatic polyol, in amounts providing 0À05-1À8 OH groups per ester-exchangeable group in (i) (cf. Specification 1,357,197), and (2) a polyvinyl alkylal, preferably in amount 0À1-2 wt. per cent of (1). Preferred compositions contain zinc, amounting to, e.g. 50-98 wt. per cent of the total composition; preferably (i) is ethyl orthosilicate and (ii) is ethylene glycol, in molar ratio 1 : 0À3-3À5; a solvent may be present. In the examples binders are obtained from ethyl orthosilicate with 1À3-3 molar parts of ethylene glycol, or from "ethyl silicate 40" and ethylene glycol and ethoxyethanol, mixed with 1-10 phr of polyvinyl butyral (added as a 15% solution in MEK or a 20% solution in ethoxyethanol) and optionally 5-15 phr of talc; they are mixed with Zn dust, in 1 : 1 to 1 : 4 wt. ratio ; there may also be added ZnO and Al 2 O 3 ; methanol, ethoxyethanol, xylene, or naphthol spirits; ZnCl 2 ; bentone, and a melamine-formaldehyde resin.</p> |
