Patent GB-653569-A (GB)
Title: Improvements in or relating to the bonding together of artificial silk and rubber
IPC: C08J5/06
Filed: 1948-05-15
Abstract: Artificial silk, e.g. rayon or nylon, is coated or impregnated with a permanently-fusible, permanently-soluble dihydroxybenzene aldehyde resin, in order to improve its bonding properties with rubber or synthetic rubber.  The resins may be made as described in U.S.A. Specification 2,385,372, or by slowly adding an aldehyde, with constant agitation, to an aqueous solution of a dihydroxybenzene, containing a catalyst, e.g. oxalic acid. Molecular proportions of aldehyde to dihydroxybenzene from 1 : 2 to 9 : 10 may be employed, the preferred proportion being 2 : 3. Resorcin, catechol or hydroquinone may be used as the dihydroxybenzene; and formaldehyde, acetaldehyde, paraldehyde, propionaldehyde, the butyl aldehydes, or the furfuraldehydes as the aldehyde component.  Specifications 477,380, 577,985, [Group VIII], 582,210 and 585,060 are referred to. Reference has been directed by the Comptroller to Specification 618,705, [Group V].ALSO:Artificial silk (e.g rayon or nylon) is coated or impregnated with a permanently fusible, permanently soluble dihydroxybenzene aldehyde resin, in order to improve its bonding properties with rubber or synthetic rubber.  The resins may be made as described in U.S.A.  Specification 2,385,372, or by slowly adding an aldehyde, with constant agitation, to an aqueous solution of a dihydroxybenzene, containing a catalyst, e.g. oxalic acid. Molecular proportions of aldehyde to dihydroxybenzene from 1 : 2 to 9 : 10 may be employed.  Resorcin, catechol or hydroquinone may be used as the dihydroxybenzene, and formaldehyde, acetaldehyde, paraldehyde, propionaldehyde, the butyl aldehydes or the furfuraldehydes as the aldehyde component.  The resin may be applied to the artificial silk as a solution in water or in a non-aqueous solvent such as methanol or anhydrous ethyl alcohol. The silk, when dried, should preferably contain from about one-half per cent to about 5 per cent of its weight of the resin. Artificial silk fibres may be passed through a solution of the resin as a stage in their manufacture, e.g. after rayon has been spun, washed, neutralized and dried, it may be moistened with a solution of the resin and subjected to a tensioning operation, to increase strength and reduce stretch, before weaving. In examples, woven rayon and nylon fabrics are treated with permanently fusible, permanently soluble resorcin formaldehyde resin solutions, assembled with plies of rubber or synthetic rubber mixes, and the latter vulcanized.  Specifications 477,380, 577,985, [Group VIII], 582,210 and 585,060 also are referred to.  Reference has been directed by the Comptroller to Specification 618,705, [Group V].ALSO:Artificial silk (e.g. rayon or nylon), is coated or impregnated with a permanently fusible, permanently soluble dihydroxy benzene aldehyde resin, in order to improve its bonding properties with rubber or synthetic rubber.  The resins may be made as described in U.S.A. Specification 2,385,372 or by slowly adding an aldehyde, with constant agitation, to an aqueous solution of a dihydroxy benzene, containing a catalyst, e.g. oxalic acid.  Molecular proportions of aldehyde to di - hydroxybenzene from 1 : 2 to 9 : 10 may be employed, the preferred proportion being 2 : 3. Resorcin, catechol or hydroquinol may be used as the dihydroxy benzene, and formaldehyde, acetaldehyde, paraldehyde, propionaldehyde, the butyl aldehydes or the furfuraldehydes as the aldehyde component.  The resin may be applied to the artificial silk as a solution in water or in a non-aqueous solvent such as methanol or anhydrous ethyl alcohol; the silk when dried should preferably contain from about one-half per cent to about 5 per cent of its weight of the resin.  Artificial silk fibres may be passed through a solution of the resin as a stage in their manufacture, e.g. after rayon has been spun, washed, neutralized and dried, it may be moistened with a solution of the resin and subjected to a tensioning operation, to increase strength and reduce stretch, before weaving.  Unvulcanized rubber may be applied to the fibres by calendering or extrusion, by deposition from latex or by pressing the fibre between layers of rubber. Compounded natural rubber, butadiene acrylonitrile copolymer or butadiene styrene copolymer types of synthetic rubber, copolymers of isobutylene and isoprene, and neoprene type synthetic rubbers may be used.  The assembly is then vulcanized by heat treatment, preferably under pressure, using sulphur, or, in the case of neoprene, zinc oxide, as the vulcanizing agent.  In examples: (1) a section of medium weight square woven rayon fabric was soaked for 1 hour in a solution comprising 50 parts of a permanently fusible, permanently soluble resorcin formaldehyde resin, 6 parts of 30 per cent ammonium hydroxide solution and 1950 parts of water, removed, blotted and dried.  It retained about 2.5 per cent of resin.  Pieces of the treated fabric were then laminated with sheets of unvulcanized compositions of rubber, neoprene, butadiene-styrene copolymer, polymerized isobutadiene or butadiene acrylonitrile copolymer, and the compositions were vulcanized by heating under pressure in a mould; (2) a square woven nylon fabric was soaked for 1 hour in solutions comprising 437.5 parts of water, 62.5 parts of a permanently fusible, permanently soluble resorcin aldehyde resin and 15 parts of concentrated ammonium hydroxide solution or 57 parts of 10 per cent potassium hydroxide solution, blotted, dried and laminated with uncured black rubber stock, the latter then being vulcanized; (3) a medium weight square woven viscose rayon fabric was soaked in a solution comprising 457 parts of ethyl alcohol, 42.5 parts of permanently fusible, permanently soluble resorcin aldehyde resin, and 38.6 parts of 10 per cent potassium hydroxide solution, blotted, dried and assembled with layers of uncured black rubber stock, the latter then being vulcanized.  Specifications 477,380, [Group IV], 577,985, [Group VIII], 582,210 and 585,060 are referred to.  Reference has been directed by the Comptroller to Specification 618,705.