| 摘要 |
<p>1,219,625. Polyurethane prepolymer/vinyl coating compositions. UNION CARBIDE CORP. 11 June, 1968, No. 27782/68. Heading C3R. [Also in Division B2] A moisture-curing coating composition comprises (a) 90 to 60% by weight of an NCO- terminated reaction product of (1) an ester diol of the formula or a polyester derived therefrom by reaction with an organic dibasic acid, and (2) a diisocyanate; and (b) 10 to 40% by weight of a normally solid copolymer of vinyl chloride and a vinyl ester containing at least 80% by weight based on the weight of copolymer of vinyl chloride copolymerized therein. The preferred M.W. of reaction product (a) is 1000 to 5000 and when it is prepared from a polyester and diisocyanate, the polyester is preferably based on an aromatic or alicyclic dibasic acid. Suitable copolymers (b) are vinyl chloride/vinyl acetate copolymers. In examples, product (a) is prepared from tolylene diisocyanate and (i) the ester diol, (ii) a polyester derived from the ester diol and isophthalic acid and (iii) a polyester derived from the ester diol and phthalic acid and are mixed with a vinyl chloride/vinyl acetate (87/13) copolymer in a mixed solvent. The mixtures are coated on to steel and wood panels and left to cure at ambient temperature and humidity.</p> |
