Patent GB-665619-A (GB)
Title: Improvements in or relating to the manufacture of composite products of textile materials and rubber
IPC: C08J5/06
Filed: 1948-12-04
Abstract: In the manufacture of composite products having rubber bonded to textile materials not incorporating metal wires, the textile material is coated with casein free from rubber latex, embedded in a vulcanizable rubber composition and the rubber vulcanized.  The rubber may be either natural rubber or a vulcanizable synthetic rubber, in particular a polymer of a conjugated diene hydrocarbon or a copolymer thereof with a minor amount of a second unsaturated compound.  The textile material may be composed of a natural vegetable fibre, e.g. cotton, or may particularly be composed wholly or in part of artificial yarns, e.g. of nylon or rayon.  The latter may be regenerated cellulose produced by the viscose or cuprammonium process or by the saponification of cellulose acetate.  The regenerated cellulose may have casein or a heat-hardening aldehyde resin dispersed therein, e.g. it may be made from viscose containing up to 5 per cent by weight (preferably 0.5-2 per cent) of a heat hardening phenol-formaldehyde resin such as a resorcinol-formaldehyde resin, or from viscose containing similar proportions of casein.  The coating of casein may be applied to the textile material when the latter is in the form of fabric by spraying on to it an aqueous solution of casein containing no admixture of latex.  When the textile material is in the form of cords or threads the casein may be applied by passing them through a bath of casein solution containing for example 0.5-2 per cent by weight of casein or over a licking wheel supplied with a casein solution containing, for example, 5-10 per cent by weight of casein.  After the textile material has been treated with casein it is dried.  The casein may be present in the solution as ammonium caseinate or as an alkali metal caseinate, the solvent being water.  The casein solution is preferably prepared by dissolving casein in water containing ammonia in amount slightly in excess of that required to form ammonium caseinate.  The solution may also contain a preservative for the casein, e.g. sodium pentachlorophenate or parachlorometacresol, the amount of preservative being for example 1-5 per cent by weight of the casein. The vulcanizable rubber composition may be applied to the dried casein-coated textile material by calendering or spreading, and then, after any moulding or other shaping step which may be necessary, the assembly is vulcanized.  Thus in the manufacture of rubber-covered weftless fabrics suitable as the plies of a tyre carcass, a plurality of parallel cords are passed through the nip between two calender rolls to each of which a vulcanizable rubber composition is applied. The application of casein free from latex to textile materials prior to the embedding of the latter in rubber is said to improve the adhesion between the rubber and the textile materials without detrimentally affecting the flexibility of the latter, as occurs when it is coated with a mixture of rubber latex and casein or with a phenol-aldehyde resin composition. Specifications 573,758, [Group VIII], 580,776 and 582,210 are referred to.