Laminated article

A light-coloured sidewall of a tyre containing natural and reclaim rubber, is made resistant to staining by migration of material from other parts of the tyre by making it of, or vulcanising it to the tyre through an intermediate layer of, a chlorinated butyl rubber, namely a chlorinated copolymer containing 80-99,5 parts of an isoolefin having 4-8 carbon atoms and 20-0,5 parts of an open chain conjugated diolefin having 4-7 carbon atoms, particularly isoprene, the chlorine content of the copolymer being 0,8-1,5% preferably about 1%. The sidewall or the barrier layer may contain 5-20% of chlorosulphonated polythene and/or 1-10% a non-reactive phenolformaldehyde condensation product such as poly-2,6-dimethylol-4 methyl, octyl, or phenyl phenol. The following compositions are described (1) chlorinated butyl rubber, made by adding 4% of dichlorodimethyl hydantoin and 1% stearic acid to butyl rubber in a mixer; (2) unstainable sidewall compositions containing 80 parts of chlorinated butyl rubber, 20 parts of chlorosulphonated polythene or 20 parts of natural rubber, 20 parts of zinc oxide, 0-10 parts of a poly dimethylol alkyl phenol, and substantial proportions of titanium dioxide, magnesia, and silica; (3) a stainable sidewall composition comprising mainly crude pale crepe rubber with 25% of white pigments and minor proportions of pine oil, stearic acid, wax, and zinc oxide; (4) a black tyre composition comprising about equal parts of crude natural and reclaimed rubber, about 10% of clay, and minor proportions of pine tar, stearic acid, burgundy pitch, and zinc oxide.