Patent GB-541558-A (GB)
Title: Improvements in and relating to photographic colloid layers
IPC: G03C7/388
Filed: 1940-05-30
Abstract: 541,558. Alkyd resins and compositions thereof. DU PONT FILM MANUFACTURING CORPORATION. May 30, 1940, No. 9522. Convention date, May 31, 1939. [Class 2 (iii)] [Also in Group XX] An aqueous dispersion of a substantially insoluble pigment, dye, dye-intermediate, or colour former containing a water soluble salt of an alkyd resin as dispersing agent is incorporated in a colloid emulsion, which may be sensitized with light-sensitive silver halide or with a bichromate or may be in-sensitized, as for example in the water-permeable intermediate layers of colour photographic multi-layer films. The colloid may be gelatin, gum arabic or albumen. In preparing the resin, the polyhydric alcohol may be glycerol, ethylene glycol, diethylene glycol, pentaerythritol, sorbitol,polyglycerol, and ethers of polyhydric alcohols which still contain at least two alcohol groups, such as glycerol monbenzyl ether and the diethyl ether of pentaerythritol. The polybasic acid may be phthalic anhydride or adipic, succinic, sebacic, fumaric, tartaric, citric, salicylacetic, hexahydrophthalic, malic, naphthalic, or maleic acid. Mixtures of the alcohols and of the acids may be used. Modifying agents such as drying oil acids ; rosin acids ; monocarboxylic acids ; monohydric alcohols such as butyl alcohol, benzyl alcohol, #-ethoxy ethanol, and cyclohexanol ; and esters such as cotton-seed oil, coconut oil, castor oil, linseed oil, China wood-oil, perilla oil, soya bean oil, rosin glyceride, stearin, and dibutyl phthalate may be added. In preparing the resin, the mixture is heated at 150-250C, heating being discontinued before the infusible, insoluble stage is reached and preferably when the resin has an acid number of 50 to 200. The preparation of the water-soluble salt may be effected while the resin is still molten or after cooling and pulverizing, or after solution in an organic solvent. The alkaline substance may be an alkali metal or ammonium hydroxide, carbonate, or phosphate, a primary, secondary, or tertiary-aliphatic, cycloaliphatic, aromatic, or heterocyclic amine, or a quaternary ammonium compound. Water-insoluble colour formers specified are resorcinol mono-n-octadecyl ether, stearyl-1-1m-aminophenyl-3-methyl- 5-pyrazolone, the pyridinium colour formers described in Specification 504,376 and the acetoacetamide colour formers described in Specification 458,664, [Group XX]. The emulsion may alternatively contain the leuco form of idanthrene or anthraquinone dyes, a dye image being produced simultaneously with the silver image. Dyes for the dye destruction process may also be added to the emulsion. Intermediate filter layers may be formed from a gelatine solution in which titanium ferrocyanide is dispersed. The following examples illustrate the preparation of resins. (A) A mixture of glycerol, phthalic anhydride, and raw castor oil is heated to 200C. during one hour and heating is continued for a further two hours. The resin, after cooling is dissolved in aqueous ammonia solution. (B) A mixture of cotton-seed oil and glycerol to which has been added a little sodium hydroxide is heated to 250C. during one hour and kept at this temperature for 20 minutes. Phthalic anhydride is added and the resin heated for 1<SP>1</SP>/ 3  hours at 200C. The temperature is allowed to fall to 125C. and the molten resin is dissolved in aqueous sodium hydroxide solution (C) A mixture of glycerol and phthalic anhydride is heated to 200C. during one hour and is kept at this temperature' for an additional hour. The molten resin is dissolved in aqueous ammonia. (D) A mixture of ethylene glycol, glycerol, and adipic acid is heated to 200C. during one hour and is kept at this temperature for an additional hour. The product is dissolved in aqueous sodium hydroxide solution. The following examples illustrate the use of the resins. (1) An aqueous ammoniacal solution of resin A is added to an ethanol solution of resorcinol mono-n-octadecyl ether and the mixture added to a panchromatic gelatino-silver-halide emulsion which is then coated on rubbed cellulose nitrate base. After exposure and development with p-aminodiethylaniline, bleaching with potassium-ferricyanide solution and fixing, a blue-green image is obtained. (2) The procedure is as in (1), except that the triethanolamine salt of resin B is used, the base is cellulose acetate, and the developing agent is p-aminodimethylaniline base (3) The colour former is 1-(m-stearylaminophenyl)-3-methyl-5-pyrazolone, the resin is prepared from coconut oil, diethyleneglycol, glycerol, and phthalic anhydride, and on addition of the mixture of resin and colour former to an orthochromatic emulsion no additional alkali is needed. Development with p-aminodiethylaniline gives a magenta image. (4) Prussian blue is added to the potassium salt of resin D and the resulting dispersion added to a photographic emulsion which is coated on cellulose nitrate base. The addition of the resins results in harder emulsions. Specifications 415,756 and 428,158, [both in Group XX], also are referred to.