Patent GB-1065418-A (GB)
Title: Improvements in or relating to stiffener material
IPC: D06N7/00
Filed: 1964-05-12
Abstract: Sheet material from which blanks suitable for use in stiffening end portions of shoe uppers can be cut out comprises a water-laid layer of heat-fusible synthetic resin particles and fibres the ratio of particles to fibres being 0.5-5:1 by weight, the layer having on at least one side thereof a layer of thermoplastic adhesive fusible at temperatures which soften the particles.  The fibres may be cellulosic and may include cotton, nylon, hemp, hair, wool, leather, asbestos, kraft or sulphite pulp fibres.  The heat-fusible synthetic resin particles may be any polymer or copolymer of syrene, vinyl toluene, vinyl acetate, and the C1-4 alkyl acrylates and methacrylates.  A fibrous fabric sheet may be provided on one side of the water-laidlayer.  This composite sheet may be impregnated from the reinforcing fabric side with an aqueous dispersion of a binder. The latter be a thermoplastic material.  Specified binder compositions are latices of styrene polymers and copolymers and polymers of C1-4 alkyl acrylates.  After impregnation the sheet is dried, and the adhesive material is applied.  The water-laid layer may be formed by straining papermaking furnish containing dispersed thermoplastic particles through a fibrous fabric sheet. Such a sheet may be held to the water-laid fibrous layer deposited from the furnish by an interspersion and entanglement of the fibres of the layer with the fibres of the fabric.  In an example, an aqueous dispersion of kraft fibres and beads of a copolymer of vinyl toluene and ethyl hexyl acrylate was introduced into the flow box of a cylinder-type papermaking machine, on the screen of which was laid a woven cotton cloth.  The dispersion was applied to the cloth on the cylinder screen to form a layer of fibre and resin particles, which after being passed through rolls to squeeze water from it, was adherent to the cloth.  The composite sheet was dried and impregnated with a binder liquid consisting of an aqueous dispersion of acrylate modified polystyrene latex and butyl benzyl phthalate.  The impregnated sheet was dried, rolled, and coated on both sides with a resin emulsion comprising a copolymer of vinyl acetate and a C6 or higher alkyl acrylate.ALSO:Sheet material from which blanks suitable for use in stiffening end portions of shoe uppers can be cut out comprises a water-laid layer of heat-fusible synthetic resin particles and fibres, the ratio of particles to fibres being 0.5-5:1 by weight, the layer having on at least one side thereof a layer of thermoplastic adhesive fusible at temperatures which soften the particles.  The fibres may comprise cellulosic fibres and may include cotton, nylon, hemp, hair, wool, leather, asbestos, kraft or sulphite pulp fibres.  The heat-fusible synthetic resin particles may be any polymer or copolymer of styrene, vinyltoluene, vinyl acetate, and the C1-4 alkyl acrylates and methacrylates.  The thermoplastic adhesive may be polyvinyl actetate, a polyamide, a polyester, a polyester amide resin, polyethylene, a copolymer of ethylene with vinyl acetate and methyl acrylate or ethyl acrylate, or a mixture thereof.  A fibrous fabric sheet may be provided on one side of the layer of heat-fusible synthetic resin particles and fibres.  The fabric may be open woven or non-woven fibrous fabric.  It may be made of cotton or rayon.  The composite sheet of water-laid layer and fibrous fabric sheet may be impregnated from the reinforcing fabric side with an aqueous dispersion of a binder, which may be a thermoplastic material. Specified binder compositions are latices of styrene polymers and copolymers and polymers of C1-4 alkyl acrylates.  After impregnation, the sheet is dried, and the adhesive material is applied.  In examples, a water-laid layer of kraft fibres and particles of a co-polymer of vinyl toluene and ethyl hexyl acrylate are held on a woven cotton cloth, the composite being impregnated with a binder composition comprising acrylate-modified polystyrene and coated on both sides with an emulsion comprising a copolymer of vinyl acetate and C6 or higher alkyl acrylate. Alternatively, the composite is impregnated with a butadiene-styrene copolymer and coated on both sides with a hot melt coating composition comprising a copolymer of ethylene and vinyl acetate, petroleum refinery wax, and a hydrocarbon resin.