Patent GB-1220951-A (GB)
Title: Coated flexible sheet material
Inventor: MARRIOTT ANTHONY GEOFFREY
IPC: D04H5/02
Filed: 1968-01-10
Abstract: 1,220,951. Laminates. DUNLOP CO. Ltd. 1 Jan., 1969 [10 Jan., 1968; 28 March, 1968], Nos. 1359/68 and 14859/68. Heading B5N. [Also in Division B2]  A flexible sheet material comprises a compressed sheet of a cellular plastics material laminated with another sheet of cellular plastics material and/or with a fibrous layer, the laminate having a multi-layer coating comprising a primary coating layer of a flexible cross-linked polyacrylate composition and an outer coating layer of a harder composition. The polyacrylate may be cross-linked by means of polymer units which have functional groups cross-linkable in the presence of hydrogen ions, e.g. hydroxyl and/or carboxyl groups, the preferred polymer having methylol groups directly attached to the nitrogen atom of an amide group. The crosslinked polyacrylate may comprise at least 50% by weight of units derived from an acrylate monomer whose homopolymers have a glass transition point below 15‹ C., e.g. alkyl esters of acrylic acid and of methacrylic acid in which each alkyl group has more than four carbon atoms. Units derived from monomers whose homopolymers have a glass transition point above 15‹ C., e.g. styrene, alpha-methyl styrene, methyl methacrylate and acrylonitrile, may also be present. Cross-linking agents may be used, e.g. melamine-aldehyde resin, ureaaldehyde resin, benzoguanamine-aldehyde resin, phenol-resin or an epoxy resin. The outer coating layer may be a composition of the same polymer but having a higher pigment to polymer ratio than the primary coating layer; or an acrylate copolymer having a higher proportion of polymer units derived from monomers whose homopolymers have a glass transition point above room temperature; polyvinyl chloride; nitrocellulose; polyurethane; or a soluble nylon, e.g. a methylated nylon having pendant methoxy groups. One or more coating layers of the same or different compositions may be present between the primary and outer coating layers. The coatings may be applied by spraying, brushing, film-transfer from, e.g. a release paper. The outer layer may be embossed after application to the flexible sheet material or by means of a relief-patterned release material in a filmtransfer technique. The cellular plastics material may be a foam of natural rubber, synthetic rubber, polyvinyl chloride, polyethylene, polypropylene or polystyrene, or of polyurethane foam. The cellular plastics material may have an at least partially open-cellular structure and may be reticulated. The compressed sheet may form part of a laminate with another sheet of a cellular plastics material and/or with a fibrous layer. The laminate may include two or more cellular plastics sheets having different densities. The density may vary throughout one or more of the sheets. Textile fibres may be distributed within the compressed sheet and/or the other cellular plastics sheet. The fibrous layer may be woven, knitted, non- woven fabric made of fibres of rayon, cotton, wool, polypropylene, polyester or polyamide. The flexible sheet material may be impregnated with a binder, e.g. a natural or synthetic elastomer. In Example 1 a laminate of a non-woven synthetic fibre felt, a woven nylon fabric and a highly compressed reticulated polyurethane foam is described. The non-woven fibre felt was made by laying a crimped nylon fibre web on a staple fibre non-woven web of polypropylene staple fibres, needle-punching the assembly. The woven nylon fabric was sprayed on both sides with a polyurethane adhesive as a discontinuous pattern. The adhesive-coated woven fabric was laid on the compressed reticulated polyurethane foam and the fibre felt was laid on top of the woven fabric with its polypropylene face in contact with the woven fabric. The assembly was laminated, and the adhesive cured by being held in contact with a rotating drum for two minutes at 140‹ C., 5 pounds per square inch pressure. The resulting laminate was floated, foam layer uppermost, on a natural rubber latex composition and the impregnated laminate was heated in a steam oven to gel the latex and then cured in steam for ten minutes at 100‹ C. The foam surface of the laminate was spray-coated with a cross-linkable polyacrylate dispersion followed by a dispersion of the same crosslinkable polyacrylate having a greater pigment concentration.