GB581520A - Improvements in and relating to bonding fabrics to natural and synthetic rubber - Google Patents

Abstract

Agents for bonding regenerated cellulosic, nylon or glass fabrics to natural or synthetic rubber, e.g. poly-2-chloro-1.3-butadiene or poly-1.3-butadiene, are emulsions or dispersions of modified alkyd resins in aqueous solutions of either protein material or partial resinification products of monohydric or polyhydric phenols and aldehydes. The alkyd resins are modified with semi-drying oils, linseed oil, linseed-tung oil mixtures, or thermohardening urea-formaldehyde resins. The latter type may be mixed with a non-drying oil modified alkyd. Suitable proteins are casein, gelatine, glue, blood albumin, egg albumin, or corn or bean proteids. Casein or similar proteins may be dissolved with the aid of ammonia, sodium phenate or sodium trichlorphenate. The preferred partial resinification products are those from resorcinol, phloroglucinol or resorcinol and formaldehyde, acetaldehyde, benzaldehyde or furfural. The solutions of these partial condensation products may include resinification catalysts, e.g. sodium hydroxide or hexamethylenetetramine. The bonding agent is applied to the fabric by dipping, spreading, brushing or spraying, the fabric dried and, if desired, heated to temperatures up to 155 DEG C. The natural or synthetic rubber stock is then applied to the fabric and vulcanized. In example 1, a solution of a urea-formaldehyde modified glyceryl phthalate resin in b -ethoxyethyl alcohol is emulsified in aqueous ammonia, and aqueous ammoniacal casein is added with stirring. The emulsion is used to impregnate rayon tyre cords which are then pressed on to a layer formed from a rubber mix containing smoked sheet, zinc oxide, carbon black, stearic acid, sulphur and mercaptobenzthiazole, and the layer is vulcanized Comparison with untreated cords applied to a similar layer showed better adhesion for the treated cords. Example 2 is similar, but employs a long oil linseed oil-modified glyceryl phthalate resin. Example 3 is also similar to example 1, but employs an emulsion containing mixed urea-formaldehyde modified glyceryl phthalate resin and castor oil-modified alkyd resin together with a partial condensation product from resorcinol and formaldehyde. Example 4 employs a resorcinol-formaldehyde partial condensation product in conjunction with a long oil linseed oil-modified glyceryl phthalate resin. Specifications 461,650 and 477,380 are referred to.