Abstract: The bond strength between a sulphur-vulcanisable rubber and a metal, especially brass, is increased by using as bonding promoter an organic substance containing one or more groups of the formula --S--SO.sub.2 R where R represents (a) a radical --OM where M is a monovalent metal, the equivalent of a multivalent metal, a monovalent ion derived by the addition of a proton to a nitrogeneous base or the equivalent of a multivalent ion derived by the addition of two or more protons to a nitrogeneous base, or (b) an organic radical. Preferred promoters include sodium, zinc, nickel and cobalt organothiosulphates.

Abstract: Compounds containing an organic thiosulphate anion and cationic nickel or cobalt in association with an amine, are useful in increasing the bond strength between metal, especially brass, and vulcanized rubber. Typical complexes are those where the anion is dodecylthiosulphate or hexamethylenebis(thiosulphate), and the amine is ethylenediamine or N-benzyl-N-t-octylamine.

Abstract: The bond strength between a sulphur-vulcanizable rubber and a metal, especially brass, is increased by using as bonding promoter a compound having the formula R--(CH.sub.2).sub.a --S.sub.2 O.sub.3.sup.- M.sup.+ or a hydrate thereof, where a has an integral value of at least 1, and where (i) M.sup.+ represents a sodium ion or an equivalent of a divalent nickel or cobalt ion and R represents hydroxy, cyano, chlorophenyl, fluorophenyl, nitrophenyl, alkoxyphenyl, alkylphenyl, dialkylphenyl, arylphenyl, naphthyl, alkylnaphthyl, benzoyl, phenoxy, halophenoxy, phthalimido, a group having the formula R.sup.2 CONH--, R.sup.2 NHCO--, where R.sup.2 is an alkyl or aryl radical, .sup.+ MOOC, or 2,4-dihydroxy-6-pyrimidyl (or its keto-form equivalent) or (ii) M .sup.+ is absent and R represents a grouping .sup.+ H.sub.3 N--.

Abstract: The bond strength between a sulphur-vulcanizable rubber and a metal, especially brass, is increased by using as bonding promoter an organic substance containing one or more groups of the formula --S--SO.sub.2 R where R represents (a) a radical --OM where M is a monovalent metal, the equivalent of a multivalent metal, a monovalent ion derived by the addition of a proton to a nitrogeneous base or the equivalent of a multivalent ion derived by the addition of two or more protons to a nitrogeneous base, or (b) an organic radical. Preferred promoters include sodium, zinc, nickel and cobalt organothiosulphates.