Patent GB-536680-A (GB)
Title: Improvements in or relating to photographic light-sensitive elements
IPC: G03C1/38
Filed: 1939-08-17
Abstract: 536,680. Photographic antihalation and protective layers. KODAK, Ltd. (Eastman Kodak Co.). Aug. 17, 1939, No. 23701. [Class 98 (ii)] Photographic light-sensitive material is provided with an overcoating or antihalation layer, removable in processing baths and therein or in or as a layer in contact therewith a wetting agent comprising a water-soluble salt of an ester of a sulphonated aliphatic dicarboxylic acid or an alkylaryl sulphonate. The overcoating or antihalation layer may consist of a cellulose ester containing a free carboxyl group such as cellulose acetate phthalate, cellulose acetate succinate, or cellulose acetate maleate, and water-soluble salts thereof, such as the ammonium and amine salts ; cellulose ethers such as ethyl cellulose phthalate ; polyvinyl phthalate ; polyvinyl alcohol ; and agar phthalate. The support may be glass ; cellulosic material such as cellulose nitrate, cellulose acetate, cellulose acetate propionate, or cellulose acetate butyrate ; or a synthetic resin such as polyvinyl acetalaldehyde acetal resin. The support may carry a backing layer of cellulose acetate phthalate over which is applied an antihalation dye or pigment layer containing the wetting agent, or the emulsion may be provided with an overcoating layer of a water-soluble or hydrophile cellulose ester or synthetic resin containing the wetting agent. The wetting agents may have the formula XOOC-R-COOX<SP>1</SP>, where R is an aliphatic carbon chain containing at least one sulphonic acid group but no other substituent, X is a hydrogen atom or the radical of an alcohol containing not more than twelve carbon atoms or of a phenol not connected by a carbon to carbon bend to R, and X<SP>1</SP> is such alcohol or phenol radical. Examples are the calcium or sodium salts of diamyl sulphosuccinate (Aerosol AY); the sodium salt of dioetyl sulphosuccinate (Aerosol OT) ; the sodium and organic amine, such as methylamine and triethanolamine, salts of the methyl, ethyl, butyl, amyl, hexyl, and octyl esters of mono- and di-sulphosuccinic, sulphochlorsuccinic, sulphoadipic, sulphomaleic, sulphopyrotartaric, and sulphoglutaric acids ; and the alkyl aryl sulphonates in which the aryl group is benzene, naphthalene, anthracene, and diphenyl and the alkyl group contains 3 to 18 carbon atoms, specific examples being sodium p-alkylbenzene sulphonates (the alkyl group ranging from heptyl to heptadecyl) known as Nacconal KP, sulphonated alkyl diphenyls known as Areskap, Aresket and Areskelene and sulphonated isopropyl naphthalenes such as sodium isopropyl naphthalene sulphonate (Aerosol OS), and di - isopropylnaphthalene sulphonate (Aquarex). A solution of wetting agent is applied to the overcoating or backing layer or is applied in the dye solution itself. In examples: (1) a layer of cellulose acetate phthalate is applied to the support and is dyed with a solution of Spirit Nigrosine NB containing the sodium salt of diamylsulphosuccinate ; (2) an emulsion layer is provided with a protective layer of polyvinyl phthalate from a solution containing sodium dioctyl sulphosuccinate ; (3) a layer of cellulose acetate phthalate is applied to a support before or after the application of the emulsion and after drying is dyed with a solution of Spirit Nigrosine NF containing sodium isopropylnaphthalene sulphonate; and (4) an emulsion layer is provided with an overcoating layer of polyvinyl phthalate from a solution containing di-isopropylnaphthalene sulphonate.