IE36796B1 - Capsule-coated sheets - Google Patents

Abstract

1337140 Pressure sensitive record sheets FUJI PHOTO FILM CO Ltd 30 Sept 1971 [2 Oct 1970 27 Oct 1970 10 Nov 1970 (2) 30 Nov 1970 15 Dec 1970] 45664/71 Heading D2B [Also in Division B2] A capsule-coated sheet comprises a plastics film support having coated thereon a capsule layer, the plastics film having been subjected to at least one of the following treatments. (1) Corona discharge treatment, (2) flame treatment, (3) coating with a synthetic resin emulsion, (4) treatment by a liquid capable of swelling the plastics film or a mixture of such a liquid and a liquid not capable of swelling the film, and (5) coating with a fine granular solid material, before the application of the capsule layer, to reduce the contact angle of the surface of the film to less than 75‹. The synthetic resin emulsion in (3) may be emulsions of a vinyl acetate homopolymer, a vinyl chloride homopolymer, a vinylidene chloride homopolymer, an acrylic homopolymer, a styrene homopolymer, an ethylenic homopolymer, a butadiene homopolymer, an epoxy homopolymer, an amide homopolymer, a silicone homopolymer and copolymers thereof. Examples of the combinations of the plastics film and the swelling liquid are given. After treatment with the swelling liquid the plastics film may be treated with a non-swelling agent to coagulate the swelled surface portion to form a mat surface. Examples of the granular materials in (5) are given. They may be applied by coating or spraying a dispersion thereof in a swelling liquid for the plastics film, by coating on the plastics film a mixture of the granular material, a synthetic resin binder, and an organic solvent for the binder, or by coating on the film a mixture of the solid particles, and a hydrophilic polymer or a synthetic resin emulsion. The plastics films may be polyethylene, polypropylene, polyvinyl chloride, polystyrene, polyester, polyamide, polycarbonate or cellulose acetate. The preferred films are biaxially orientated. The capsules may be produced by (a) coacervation process from aqueous solution, (b) interfacial polymerisation, (c) polymerisation of monomer in oily droplets, (d) liquifying, dispersing and cooling waxy material, (e) spray drying, or (f) internal accumulation. In a typical Example a coacervate comprising a liquid membrane of gelatin and gum arabic formed around oily droplets containing crystal violet lactone was cooled to gel the liquid membrane and the wall mem branes hardened by adding formaldehyde solution, then aqueous sodium carboxymethyl cellulose and aqueous caustic soda. The temperature was then raised to 50‹C. and cellulose flock added to obtain a capsule liquid. Biaxially oriented polystyrene film was subjected to flame treatment to impart a contact angle of 45‹ thereto, and the support coated with the capsule liquid and dried to obtain a colourformer sheet for pressure-sensitive recording paper. [GB1337140A]