| 摘要 |
677,876. Stabilizing latex. UNITED STATES RUBBER CO. Nov. 29,1950 [Feb. 2, 1950], No. 29217/50. Class 70 The mechanical stability of formaldehyde-preserved natural rubber latex is increased by incorporating therein from .01 to 0.2 per cent by weight of polyvinyl methyl ether, polyvinyl methoxy ethyl ether or copolymers of vinyl methyl ether and vinyl methoxy-ethyl ether. The latex may contain from 0.03 to 1.0 per cent of formaldehyde and, e.g. from 0.1 to 1.0 per cent of, a volatile secondary or tertiary amine, e.g. dimethylamine, trimethyl amine or morpholine. Specification 368,193 is referred to.
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