| 摘要 |
504,549. Microporous compositions; synthetic resin articles. UNITED STATES RUBBER PRODUCTS, Inc. Nov. 8, 1938, No. 32308. Convention date, Nov. 11, 1937. [Class 70] [Also in Group IV] Microporous products suitable for battery plate separators, filters, electrolytic cells, and the like, are made from heat-hardenablo materials such as rubber, reactive phenolic or urea resins and the like, by incorporating therein highly hydrous oxide gels, and hardening under non-evaporative conditions. The preferred gel is silica which may be prepared by mixing sodium silicate and sulphuric acid, and dehydrating until a soft, friable mass is obtained containing 15-40 per cent of silica. This is milled into a rubber mix which is then vulcanized in hot water. Specification 493,639 is referred to. |
