Patent GB-967735-A (GB)
Title: Record sheet, coating composition therefor, and method of making such sheet
Inventor: GOSNELL EARL JOHN
IPC: C09D5/23
Filed: 1960-09-07
Abstract: A composition, for coating base webs to form an opaque coating that becomes translucent when subjected to local pressures (see Division D2), comprises a film-forming thermoplastic synthetic resin, a non-volatile liquid plasticizer which is a solvent for the resin and an inorganic pigment.  The resin, plasticizer and pigment together comprise at least 75% of the composition. The plasticizer is present to the extent of 0.7 to 2.8 parts by weight per part of resin.  The pigment has a refractive index less than 1.75, forms soft flocculent masses having an open structure when dispersed in aqueous vehicles, consists of particles substantially all of which are less than two microns in diameter when unagglomerated and is present to the extent of 0.4 to 2.2 parts by weight per part of resin and plasticizer.  The resin may be polyvinyl acetate, an acrylate ester polymer, a methacrylate ester polymer, a copolymer of vinyl acetate and an acrylate, a copolymer of vinyl acetate and vinyl chloride, a copolymer of vinyl acetate and vinyl stearate, or a copolymer of butadiene and styrene. The pigment may be satin white, basic aluminium sulphate, aluminium hydrate, magnesium carbonate, basic magnesium carbonate, calcium carbonate, talc, or calcium sulphate. Suitable plasticizers are benzoate, butyrate, citrate, glycolate, phosphate and phthalate esters and aryl sulphonamides.  The composition may be dispersed in an aqueous vehicle. In the examples, compositions comprise: (1) Polyvinyl acetate, polyvinyl alcohol, butyl alcohol, polyoxyethylene derivative of sorbitan monolaurate, benzyl butyl phthalate, triethylene glycol di(2-ethylbutyrate), satin white, sodium salt of naphthalenesulphonic acid condensed with formaldehyde, spray-dried sodium-lignosulphonate containing wood sugars, casein and paraffin wax; (2) Polyhexyl methacrylate, ether of polyethylene glycol and oleyl alcohol, dibutyl phthalate, polyoxyethylene stearate, basic aluminium sulphate, polyvinyl alcohol, sodium pyrophosphate and spray dried sodium lignosulphonate containing wood sugars; (3) Polyvinyl acetate, dipropylene glycol dibenzoate, polyoxyethylene sorbitan monolaurate, basic aluminium sulphate, polyvinyl alcohol, sodium pyrophosphate and spray-dried sodium lignosulphonate containing wood sugars; and (4) Polyvinyl acetate, casein, dipropylene glycol dibenzoate, acetyl tributyl citrate, basic magnesium carbonate and sodium lignosulphonate.ALSO:A pressure-sensitive record sheet comprises a base web and a coating which is substantially opaque except when subjected to local marking pressure which causes the coating to become translucent locally.  The coating comprises a film-forming thermoplastic synthetic resin, a non-volatile liquid plasticizer which is a solvent for the resin and an inorganic pigment.  The resin, plasticizer and pigment together comprise at least 75% of the composition.  The plasticizer is present to the extent of 0.7 to 2.8 parts by weight per part of resin.  The pigment has a refractive index less than 1.75, forms soft flocculent masses having an open structure when dispersed in aqueous vehicles, consists of particles substantially all of which are less than two microns in diameter when unagglomerated and is present to the extent of 0.4 to 2.2 parts by weight per part of resin and plasticizer.  The resin may be polyvinyl acetate, an acrylate ester polymer, a methacrylate ester polymer, a copolymer of vinyl acetate and an acrylate, a copolymer of vinyl acetate and vinyl chloride, a copolymer of vinyl acetate and vinyl stearate, or a copolymer of butadiene and styrene.  The pigment may be satin white, basic aluminium sulphate, aluminium hydrate, magnesium carbonate, basic magnesium carbonate, calcium carbonate, talc, or calcium sulphate. Suitable plasticizers are benzoate, butyrate, citrate, glycolate, phosphate and phthalate esters and aryl sulphonamides.  In the examples, compositions comprise: (1) Polyvinyl acetate, polyvinyl alcohol, butyl alcohol, polyoxyethylene derivate of sorbitan monolaurate, benzyl butyl phthalate, triethylene glycol di(2-ethylbutyrate), satin white sodium salt of naphthalene sulphonic acid condensed with formaldehyde, spray-dried sodium-lignosulphonate containing wood sugars, casein and paraffin wax; (2) Polyhexyl methacrylate, ether of polyethylene glycol and oleyl alcohol, dibutyl phthalate, polyoxyethylene stearate, basic aluminium sulphate, polyvinyl alcohol, sodium pyrophosphate and spray dried sodium lignosulphonate containing wood sugars; (3) Polyvinyl acetate, dipropylene glycol dibenzoate, polyoxyethylene sorbitan monolaurate, basic aluminium sulphate, polyvinyl alcohol, sodium pyrophosphate and spray-dried sodium lignosulphonate containing wood sugars; and (4) polyvinyl acetate casein, dipropylene glycol dibenzoate, acetyl tributyl citrate, basic magnesium carbonate and sodium lignosulphonate.  The record sheet is made by dispersing the composition in an aqueous vehicle, coating it on to a base web and drying.  The base web may be of paper with a deeply coloured surface, or of transparent cellulose acetate or polyethylene terephthalate or translucent glassine paper.  Coloured paper, if used may be coloured throughout, or made by laminating a thin black sheet to white paper stock, or by applying black colouring material to one side of white paper.