GB955235A - Vulcanisation process - Google Patents

Abstract

A natural or synthetic rubber is vulcanized in the presence of a trifunctional phenol resin and one or more halides of metals of Group IIa, IIb, IIIa or IIIb or halides of a heavy metal of specific gravity above 4, or a mixture of precursors for such halides. A trifunctional phenol resin is defined as one derived from the alkaline condensation of an aldehyde having from 1 to 7 carbon atoms with a trifunctional phenol and subsequent or simultaneous, partial or complete etherification of the alkylol groups of the polyalkylol resin so formed. A trifunctional phenol is a phenol in which the groups ortho,- ortho and para to the phenolic hydroxy group are not blocked by either direct substitution or by steric hinderance and any substituents in the meta positions do not contain more than 3 carbon atoms altogether. Specified aldehydes are acetaldehyde, propionaldehyde, butyraldehyde, crotonaldehyde, benzaldehyde and furfural but formaldehyde is preferred, while m-cresol, 3-5-xylenol and (preferred) phenol are specified phenols-a minor proportion of a phenol not meeting the above requirements may also be present. The alkylol groups of the polyalkylol compounds, obtained by the reaction of 2 to 3 mols of aldehyde with the phenol may be partially etherified with monohydric alcohols to such an extent that they are still soluble in organic solvents. Methyl and higher alcohols and benzyl-alcohol are specified. The partially etherified resins may be modified e.g. plasticized by heating to above 70 DEG C. with a hydroxy fatty acid containing more than 10 carbon atoms or a glyceride thereof. The resins may also be plasticized with fatty oils, urea resins, and polyester resins. Specified elastomers are natural rubber, butyl rubber, halogenated butyl rubber, polybutadiene, polyisoprene, polychloropreneazo/copolymer of butadiene and/or isoprene with styrene or acrylonitrile. Specified halides are the chlorides of zinc, iron, aluminium, tin (ores), chromium, nickel, cobalt, and manganese, stannous chloride and aluminium fluoride. The metal halides may be produced in situ from a metal compound and a halogen-donor and the usual lists of each are given. The usual compounding and vulcanizing agents may also be present. Specification 409,397 is referred to.