GB707425A - Improvements in or relating to synthetic rubber compositions - Google Patents

Abstract

A plastic open-chain aliphatic conjugated diene polymer containing from 0.001 to 0.30 chemical equivalents by weight of combined -COOH groups per hundred parts by weight of polymer, is mixed with a polyvalent metallic oxide, and heated at 125 to 400 DEG F. until salt formation occurs. Specified metallic oxides are those of zinc, magnesium, cadmium, calcium, titanium, aluminium, barium strontium, copper, cobalt and tin. The polymer may be prepared (1) by polymerizing in an acidic aqueous medium, a monomeric mixture of at least 50 per cent. of the diene and an olefinically-unsaturated carboxylic acid, or (2) by reacting a diene polymer with a carboxylating agent or carboxyl-supplying reagent, preferably in the presence of an oxidizing agent, or (3) by reacting with a hydrolysing agent an interpolymer of a diene and an unsaturated copolymerizable material containing a group hydrolysable to a carboxyl group. Specified dienes are butadiene- 1:3, 2 -methyl butadiene-1:3, 2, 3-dimethylbutadiene -1:3, piperylene, 2-neopentyl butadiene- 1:3, 2 -chlorobutadiene 1:3, 2 -cyano -butadiene- 1:3, pentadienes and hexadienes. Specified olefinically unsaturated carboxylic acids are acrylic acid, the alpha-alkyl acrylic acids, b - methyl and b - benzal acrylic acids, crotonic, a - butyl and a - methyld - benzal crotonic acids b - acryloxy propionic acid, a and b - vinyl acrylic acid, a -b -isopropylidene propionic acid, sorbic and hydrosorbic acids, cinnamic acidm- and p-chlorocinnamic, maleic and fumaric acids, undecylenic and ricinoleic acid, linoleic acid and linolenic acid, angelic, umbellic, a - methyl, a - ethyl, a - chloro and a - bromo -sorbic acids, a , b , d or epsilondimethyl sorbic acids, and many others. A third monomer may be present. Specified are acrylonitrile, a -chloroacrylonitrile, methyl, ethyl, butyl, 2- ethylbenzyl, or noctyl acrylate, methyl, butyl or lauryl methacrylate, methyl ethacrylate, styrene, vinylidene chloride, vinyl pyridine and isobutylene. In preparations (1) an emulsifier such as sodium lauryl sulphate, the sodium salts of sulphonated paraffin oil, and lauryl amine hydrochloride (many more listed), a catalyst such as hydrogen peroxide, other peroxides, hydroperoxides, persalts, with or without reducing agents (many specified) and a mercaptan modifier may be present, while the polymerization may be short stopped with hydroquinone or phenyl b -naphthylamine. Among a long list of carboxylating agents for use in (2) are maleic acid, dimethyl maleic anhydride, beta -mercapto propionic acid, bis- (thioglycollic) anhydride, and monopotassium oxalate, which may be reacted by means of catalysts such as benzoyl peroxides, persulphates and perborates (many catalysts specified). Specified copolymerizable materials which may be used in method (3) are esters, amides and nitriles of acrylic and substituted acrylic acids, particularly the alphaalkyl and alpha -halo acrylic acids, maleates and fumarates, vinyl esters of carboxylic acids, alkyl esters of carboxylic acids, the alpha- and betacyano acrylates and related compounds, methyl betaacryloxy propionate, acrylyl chloride and allyl chloride. A third monomer such as vinylidene chloride or chlorofluoride, styrene, ochloro or omethoxy styrene, pdivinyl benzene, vinyl naphthalene, vinyl pyridine or vinyl carbazole may also be present. Here again the usual emulsifiers, catalysts and polymerization modifiers may be used. The hydrolysis method (3) may be carried out in solution in benzene, toluene, acetone, alcohol or methyl ethyl ketone by adding an acidic hydrolysing agent to a cationic aqueous dispersion of the polymer or an alkaline one to an anionic aqueous dispersion, or by reacting the solids together and treating with water or aqueous acid or by adding the hydrolysing agent to the monomer mixture. Hydrolysing agents include strong inorganic and organic acids, alkalihydroxides, quaternary ammonium bases and their salts, primary, secondary and tertiary amines, heterocyclic amines, and salts of a strong base and a weak acid.