GB1271340A - Pressure-sensitive transfer elements and process for production thereof - Google Patents

Abstract

1,271,340. Carbon paper. COLUMBIA RIBBON & CARBON MFG. CO. Inc. 23 Nov., 1970 [15 Dec., 1969], No. 55584/70. Heading D2B. A pressure-sensitive transfer sheet is formed by coating a base with a mixture which is afterwards heated in an inert atmosphere to polymerize a binder included in the mixture. The material consists of (a) a liquid acrylic ester monomer, preferably an aliphatic ester of acrylic or methacrylic acid in which the aliphatic ester radical is substituted or unsubstituted and contains from 1 to 5 carbon atoms in the aliphatic chain, for example hydroxylmethacrylate; (b) an oleaginous material; (c) colouring matter, such as carbon black, alkali blue or magnetic iron oxide; and (d) a polymerization catalyst, such as lauryl peroxide, preferably mixed beforehand with a slowly polymerizing vinyl monomer such as styrene. The oleaginous material should be incompatible with the polymer (though compatible with the monomer) in the case of a "squeeze-out" transfer sheet, for example rapeseed oil or lanolin, and compatible with the polymer in the case of a stencil-type transfer sheet, so as to soften the binder. A filler such as clay, bentonite or silica may be added. The mixture is applied at a uniform thickness of 0.3-3.0 mil., preferably 0.8 mil., to a web which passes over a scraper blade and into a chamber containing nitrogen, carbon dioxide and helium, where the material is heated by infra red lamps, for example to 200-225‹F. The mixture may also include a low-molecular weight polymer such as trimethoxy propane triacrylate. The base material may be paper or polyethylene terephthalate.