| 摘要 |
Natural and synthetic rubbers (including ethylene-propylene and ethylene-propylenediene copolymers) are rendered more tacky in the uncured state by the addition of at least one non-heat reactive p-alkylphenol-formaldehyde novolak resin wherein the p-alkylphenol has the general formula <FORM:1011124/C3/1> where R is an isomeric alkyl group containing from 9 to 15 carbon atoms. The term "isomeric" is defined as a branched chain alkyl group or, in the case of a mixture, which contains less than 50% of any one straight chain alkyl group. Small proportions of lower alkylphenol-formaldehyde resins may be used in addition. The compositions may contain other ingredients such as petroleum oil, reclaim and carbon black. Conventional vulcanizing techniques are used. Specifications 714,214 and 880,904 are referred to.
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