Patent GB-1090973-A (GB)
Title: Improved method of bonding textile material to rubber
Inventor: OSBORNE ALAN PAUL
IPC: C08K9/10
Filed: 1964-02-12
Abstract: A natural or synthetic rubber composition having improved adhesion to textile materials is produced by incorporating in the composition a polyhydric phenol and/or a partly condensed resin thereof, vulcanizing ingredients and microencapsulated particles of an unstable formaldehyde generator, which decomposes to generate formaldehyde at temperatures below 150 DEG  C., e.g. paraformaldehyde, the microencapsulated particles being microscopic particles each of which is individually provided with a sheath of a resinous material over at least a substantial part of its surface, the formaldehyde being liberated from the microencapsulated particles when the composition is vulcanized. Each particle of the formaldehyde generator may be provided with a sheath of the polymeric material, e.g. ethyl cellulose, cellulose nitrate, polypropylene, polyethylene, a copolymer of ethylene and propylene, a polycarbonate, polystyrene, cyclized natural rubber or a condensate of paratertiary butyl phenol and acetylene, over at least 50% of its surface.  The polyhdric phenol may be resorcinol or 1,5-naphthalene diol or a partly condensed phenol/formaldehyde resin may be used.  The rubber composition may be natural rubber, a butadiene/styrene rubber, a chloroprene rubber, a nitrile rubber or a blend thereof, and may also contain furnace black, zinc oxide, pine tar, mineral oil, stearic acid, N-nitroso-diphenylamine, N-cyclohexyl-2-benzothiazole sulphenamide and sulphur.ALSO:Textile materials, e.g. nylon and viscose rayon cords, are bonded to a natural or synthetic rubber composition by incorporating in the composition a polyhydric phenol and/or a partly condensed resin thereof, vulcanizing ingredients and microencapsulated particles of an unstable formaldehyde generator which decomposes to generate formaldehyde at temperatures below 150 DEG C, e.g. paraformaldehyde, the microencapsulated particles being microscopic particles each of which is individually provided with a sheath of a resinous material over at least a part of its surface, applying the composition to the textile material and vulcanising the assembly in conditions in which formaldehyde is liberated from the microencapsulated particles.  Each particle of the formaldehyde generator may be provided with a sheath of the polymeric material, e.g. ethyl cellulose, cellulose nitrate, polypropylene, polyethylene, a copolymer of ethyene and propylene, a polycarbonate, polystyrene, cyclised natural rubber or a condensate of paratertiary butyl phenol and acetylene, over at least 50% of its surface.  The microencapsulated particles may be produced by sub-dividing into droplets a feedstock comprising either a solution of a resinous material in a volatile organic liquid having the solid substance dispersed and/or dissolved therein or a dispersion in a dispersing medium of such a solution and mixing the droplets with steam in conditions in which steam condenses on the droplets and the volatile organic liquid is volatilized from each droplet while that droplet is free of external contact with a solid or bulk liquid.  The polyhydric phenol may be resorcinol or 1,5-naphthalene diol or a partly condensed phenol/formaldehyde resin may be used.  The textile material may previously have been treated with a latex-resorcinol/formaldehyde cord adhesive.  The rubber composition may be natural rubber, a butadiene/styrene rubber, a chloroprene rubber, a nitrile rubber or a blend thereof, and may also contain furnace black, zinc oxide, pine tar, mineral oil, stearic acid, N-nitrosodiphenylamine, N-cyclohexyl-2-benzothiazole sulphenamide and sulphur.