Patent GB-1406092-A (GB)
Title: Method of making a product having a desired surface electrostatic charging propensity
IPC: C08J7/044
Filed: 1972-07-17
Abstract: 1406092 Coating EASTMAN KODAK CO 17 July 1972 [16 July 1971] 33357/72 Heading B2E [Also in Divisions Gl and G2] A product having a surface containing a charge control agent to provide desired electrostatic charging characteristics is produced by (a) measuring the maximum electrostatic charge generated when the surface of a comparison product containing no charge control agent is impacted with and separated from a reference surface under standardised conditions, (b) making samples of the product having different surface concentrations of the charge control agent, (c) measuring by the procedure of step (a) the maximum electrostatic charge generated when the surface of each sample made in step (b) is impacted with the reference surface, (d) based on the results of (a) and (c) selecting a surface concentation of the charge control agent to give the desired electrostatic charging characteristics of the material, and (e) making the product with the selected surface concentration of the charge control agent. The charge control agent may be incorporated into the product during manufacture of the product or it may be coated over the surface of the product. The treatment may such as to minimise or maximise the generation of electrical changes. The product may be resin-coated paper or a polymeric film especially sensitised (radiographic or photographic) films, e.g. photographic materials comprising light sensitive silver halides suspended in gelatins and coated on a cellulose ester, polycarbonate or polyethylene terephthalate support or a gelatin subbing layer. The photographic material may be X-ray film or film for aerial film cameras. The treatment may be used to increase the surface charging of toner particles in electrophotography. The camera roller in an aerial film camera, stainless steel or anodised aluminium roller used in emulsion coating machines may be treated. Other products mentioned for treatment include layers of cellulose derivatives, polysaccharides, polyvinyl pyrrolidone acrylamide polymers on supports of cellulose nitrate and polystyrene films, glass, metal, paper which oan be partially acetylated or coated with baryta and/or an alpha-olefin polymer. The layers may also contain surfactants, conductive agents, matting agents. The invention may also be used to produce products designed for colloid transfer processes, silver salt diffusion transfer processes, colour image transfer processes and imbibition transfer processes, for recording print-out images, and direct-print images and for processing by heat, for colour photography, e.g. materials containing colour-forming couplers. The photographic materials may also contain conducting layers or compounds which may comprise soluble salts, e.g. chlorides and nitrates, evaporated metal layers, ionic polymers or insoluble inorganic salts. Preferred charge control agents are (a) surfactants containing a completely fluorinated chain, (b) sodium and potassium salts of substituted benzene sulphonic acids, (c) multi-functional carboxylic acids such as citric, tartaric and succinic acids, (d) carboxylated polymers, (e) 1-5 alkyl phosphates, (f) polymers having a repetitive halogen, nitro- or hydroxyl substituent, (g) mixtures thereof. Many examples are given.