| 摘要 |
<p>1,231,407. Coated film. KALLE A.G. 24 Sept., 1968 [25 Sept., 1967], No. 45301/68. Heading B2E. [Also in Division G2] A transparent drawing material comprises a support of polyester film and a drawing layer containing as pigment silica, calcined alumina, and/or aluminium silicate and as a binder a hardened mixture of polyvinyl alcohol, a urea/ formaldehyde or melamine/formaldehyde precondensate and an acrylic ester copolymer. The initially water-soluble polyvinyl alcohol is cross-linked by the aldehyde condensation resin. The copolymer is obtained by polymerisation of suitable monomers including methyl, ethyl, isopropyl, n-butyl, isobutyl acrylate, methyl methacrylate, methyl ethacrylate and butyl methacrylate. Suitable comonomers are styrene, alpha-alkyl styrenes, vinyl toluenes, vinyl chloride, vinyl ether, vinyl ester and acrylic acids. Mixtures of pigments of different grain size can be used. Stretched and heat-set polyester films are suitable supports, the preferred polyesters being from terephthalic acid and ethylene glycol, copolyesters of these monomers with other dicarboxylic acids, e.g. isophthalic acid and other di- or polyhydric alcohols, e.g. 1, 3-propane diol, 1, 4- butane diol, and neopentyl glycol also being used. The drawing materials may be processed to give light-sensitive reproduction materials, e.g. by providing them on the side opposite to the drawing layer with a light-sensitive reproduction layer. The drawing layer may also be sensitised by diffusion sensitisation with solutions of e.g. diazo-type mixtures. The drawing material may have an adhesive layer between the support and the drawing layer. The products do not exhibit any curling tendency. In Example I a biaxially stretched and heat-set polyethylene terephthalate film was immersed in a solution comprising 110 grammes trichloroacetic acid, 10 grammes polyvinyl alcohol 1.5 grammes anionic and non-ionic wetting agents, 890 grammes water, and dried to produce an adhesive layer. An aqueous dispersion consisting of polyvinyl alcohol having 12% acetyl group content, a partially etherified melamine/formaldehyde condensate, and a copolymer of 66% methyl acrylate, 22% vinyl isobutyl ether, and 12% styrene, and aluminium silicate pigment, citric acid, non-ionic and anionic wetting agents was poured thereon and dried.</p> |
