GB677585A - Improvements in or relating to synthetic rubbers and method of stabilizing same - Google Patents

Abstract

Synthetic rubbers, such as copolymers of butadiene with styrene or acrylonitrile, produced by the polymerization of the ingredients in latex form, are stabilized by addition to the latex, prior to coagulation, of a 2,21-methylene bis-(4,6-dialkyl phenol) of the general formula <FORM:0677585/IV (a)/1> where R1 is an alkyl radical of 1 to 3 carbon atoms, and R2 is a tert.-alkyl radical of 4 to 8 carbon atoms, the linkage from the tertiary carbon atom being directly to the benzene nucleus. Phenols specified are 2,21-methylene bis-(4-methyl-6-tert.-butyl phenol), and 2,21-methylene bis-(4-methyl-6-tert.-butyl phenol).ALSO:The preparation of 2,21-methylene bis-(4,6-dialkyl phenols) is described in examples. 2,21 - methylene - bis - (4 - methyl - 6 - tert. - butyl phenol) is prepared by treating a mixture of 4 - methyl - 6 - tert. - butyl phenol, concentrated hydrochloric acid and heptane with 36 per cent aqueous formaldehyde solution, followed by digestion at 50-60 DEG C.; after cooling the solid product is filtered off and washed with heptane-water mixture. 2,21-Methylene-bis-(4-methyl-6-tert.-octyl phenol) is prepared by treating a mixture of 2-tert.-octyl-4-methyl phenol and concentrated hydrochloric acid with 36 per cent aqueous formaldehyde, heptane is then added and the reaction mixture is heated at 55-60 DEG with stirring, the product is then washed with water, and the heptane-water mixture removed by distillation. The products are used as stabilizers for synthetic rubbers.