| 摘要 |
676,188. Preserving rubber latex. UNITED STATES RUBBER CO. Jan. 22,1951 [April 13, 1950], No. 1607/51. Class 70 Desludged Hevea rubber latex is preserved with a small amount of an alkali metal salt, ammonium or substituted ammonium salt of ethylenediamine tetraacetic acid and a small amount of ammonia or other equivalent latex preserving base. The alkali metal may be sodium and the ammonium salt substituted with alkyl groups such as methyl. The salt is preferably added in the proportion of 0.002 to 0.2 per cent and the amount of ammonia used may be reduced to 0.2 to 0.5 per cent. Ammonium alginate may also be added.
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