| 摘要 |
1484252 Viscosity stabilization of natural rubber RUBBER RESEARCH INSTITUTE OF MALAYSIA BOARD OF 18 Oct 1974 [22 Oet 1973] 49078/73 Heading C3Q A method of treating natural rubber to provide viscosity stabilization comprises adding to fresh solid natural rubber an effective amount of semicarbazide or an acid addition salt thereof. "Fresh solid natural rubber" is defined as solid natural rubber which has undergone substantially no storage hardening. The semicarbazide or salt thereof may be added at any convenient time during processing of the rubber, e.g. by dipping rubber crumb in a solution containing semicarbazide, suitably for a period of less than 1 minute, by adding semicarbazide to dry coagula or to wet coagula. The invention is applicable to smoked or unsmoked rubber, crepe rubber, solid rubber from latex, ouplumps and compounded and uncompounded rubber. The semi-carbazide or acid addition salt thereof may be added to the rubber in an amount 0À02- 0À5% by weight based on the weight of rubber. Subsequent to the addition of the semicarbazide or acid addition salt to the rubber, the rubber may be heated to a temperature not exceeding 120‹ C. and/or vulcanized. |
