Patent GB-1061656-A (GB)
Title: Leather-like material
IPC: D06N3/00
Filed: 1963-12-18
Abstract: 1,061,656. Laminates. B. F. GOODRICH CO. Dec. 18, 1963 [Dec. 19, 1962], No. 50029/63. Heading B5N. A leather-like material usable for making footwear comprises a base layer 7 to 100 mils. in thickness of a non-woven fabric of polypropylene fibres or a mixture thereof with hydrophilic fibre such as cotton or rayon containing 50 to 200% by weight of "a carboxylic modified latex saturant," an interlayer of cellulose fibre, 8 to 17 mils. in thickness, containing 15 to 50% by weight of a carboxylic modified latex saturant, and a water vapour permeable surface layer or coating 5 to 30 mils. in thickness of a polyesterurethane-vinyl resin. The non-woven fabric layer may be oriented by needle-punching. Preferred features are 50 to 150% " carboxylic modified latex saturant " in the base layer which has a fibre denier between slightly less than I and 3 and maybe orientated; 3 5% in the interlayer which is 10 mils. in thickness and formed of wet paper process cellulose fibre; and the surface layer or coating formed from 65 to 85, preferably 80, parts by weight of a polyesterurethane and 35 to 15, preferably 20, parts of polyvinyl chloride resin. The surface layer may also include ammonium bicarbonate. The layers are laminated together by a cement adhesive comprising a solution of 20 to 60 parts by weight of the polyesterurethane in 100 parts of an organic solvent containing from 20 to 120 parts by weight of ammonium bicarbonate. In a modification the polyesterurethane vinyl resin is applied as a coating by calendering. During the final heating stage the ammonium bicarbonate in the adhesive and possibly also in the surface coating or layer is given off as a gas whereby permeability of the surface layer or coating is ensured. Alternatively the surface layer or coating is punched with needle punches, up to 30,000 per sq. inch. The " carboxylic modified latex " is produced by polymerizing in an aqueous acrylic or methacrylic acid medium a monomeric mixture of at least 55% by weight of one or more alkyl acrylates or butadiene - 1,3, butadiene - styrene or butadieneacrylonitrile hydrocarbons, and 1-45% by weight of an unsaturated acid monomer. In an example a hundred yards of polypropylene non-woven fabric was dipped into an aqueous solution of a carboxyl modified acrylic latex, Trade Mark " Hycar " 2600 x 83, drawn through squeeze-rolls, then dried and air-cured on heater rolls. It was then spread on one side with adhesive consisting of a 23% solution of polyesterurethane in tetrahydrofuran containing one part ammonium bicarbonate for each part polyesterurethane and a wet-paper-process cellulose layer containing 35% carboxylic modified acrylic latex calendered Vercon and the construction dried. An adhesive comprising a 21% solution of polyesterurethane in tetrahydrofuran containing one part ammonium bicarbonate for each part polyesterurethane was spread on the upper surface of the cellulose layer. The structure was dried at room temperature to remove the solvent then placed in a wet steam autoclave for 2 hours at 100 C. to remove the ammonium bicarbonate and ensure permeability and finally hot-pressed between calender rolls.