GB725336A - Improvements in or relating to silver halide photographic film elements - Google Patents

Abstract

725,336. Anti-static photographic film. DU PONT DE NEMOURS & CO., E. I. March 4, 1953 [April 9, 1952], No. 6073/63. Drawings to Specification. Class 98 (2). A film support carries on one side a colloidsilver halide emulsion layer and on the other side a layer of a film-forming binding agent containing a Wemer-type chromium complex in which trivalent chromium is co-ordinated with an aliphatic carboxylic acid group containing less than six carbon atoms, an aromatic carboxylic acid group containing seven carbon atoms, an aralkyl carboxylic acid group containing not more than eight carbon atoms, or any such acid group containing at least one dipole group such as Cl, Br, I, nitro, hydroxy or phenoxy. In eight specific examples the film support is always polyethylene terephthalate; the binding agent is a polyvinyl alcohol base acid complex, polyvinyl alcohol or gelatin; and the chromium complex that of p-nitrophenylacetic acid, p-nitrobenzoic acid, phenyl acetic trichloroacetic acid or thioglycollic acid; but numerous other film supports generally of hydrophobic type, other binding agents of both water-permeable and resinous or hydrophobic types, and other chromium complexes are quoted. The complex may be mixed with a solution of the binding agent in water or organic solvent as appropriate and applied to the film support as from extrusion orifices or transfer rollers, or by skim coating, followed by drying, and then a sublayer, a colloid silver halide emulsion layer or a plurality of such and filter or protective layers if required are applied to the obverse side of the support. An apparatus for measuring static charges acquired by a film travelling over a roller is described, results showing that untreated polyethylene terephthalate film builds up a charge of - 20 kilovolts when passing over a brass roller and treated film only - 0.35 to - 3 kilovolts, with reduced tendency to show static markings. The chromium complexes may be made by reacting chromyl chloride with a carboxylic acid as described above in organic solvent, or by making a solution of chromium trioxide and hydrochloric acid in water with a monohydric aliphatic alcohol and then with a carboxylic acid, and preparation of the complex of p-nitrophenylacetic acid, used in Examples I and II, by this latter method is described in detail. Specifications 550,246, [Group IV], and 654,342, [Group IV (a)], are referred to.