GB1273984A - Reinforcing yarns or cords - Google Patents

Abstract

1,273,984. Reinforcing yarn. DUNLOP HOLDINGS Ltd. 24 July, 1969 [3 Aug., 1968; 29 May, 1969], Nos. 37147/68 and 27262/69. Headings DIP and D1W. A reinforcing yarn comprises an encapsulated multifilament low-twist yarn (as defined) formed from a regenerated or synthetic polymeric material in which the encapsulating material is an elastic solid having a Poissons ratio of at least 0.45 under tensile strains not greater than 5% and penetrating the whole of the yarn outer surface to a depth at least sufficient to bond together 30% of the filaments of the yarn. The elastic solid may be derived from a resorcinol-formaldehyde-latex adhesive composition which may contain butadiene, vinyl pyridine or natural rubber, and the yarn may be of rayon, nylon, polyester or polyvinyl alcohol. In the manufacture of the reinforcing yarn, a multifilament low-twist yarn is coated with a liquid which can subsequently be converted to an elastic solid having a Poissons ratio of at least 0.45 under tensile strains not greater than 5%, the depth of penetration being at least sufficient to bond together 30% of the filaments of the yarn, and the liquid is then converted into the elastic solid. In a preferred embodiment, at least two multifilament yarns are coated with the liquid and twisted together prior to the conversion of the liquid into the elastic solid. The liquid may be a solution of a polymer in an organic solvent, a solution of cis-polyisoprene in nhexane containing dicumyl peroxide or a liquid polyurethane. In a preferred embodiment the multifilament yarn is pre-treated with an adhesive. The yarns are preferably used to make cords for use in the manufacture of pneumatic tyres.