Patent GB-546631-A (GB)
Title: Improvements in or relating to photographic materials
IPC: G03C1/83
Filed: 1941-01-20
Abstract: 546,631. Synthetic resins. COLLINS, R. B. Jan. 20, 1941, No. 740. [Class 2 (iii)] [Also in Group XX] Photographic material comprises a support carrying one or more photographic emulsion layers and one or more layers, serving as antihalation or colour filter layers, which comprise a resinous indophenol or indoaniline dye, or a benzthiazine dye derived from the latter, prepared by condensing a p-aminophenol or an aromatic p-diamine with an alkali-soluble synthetic phenolic resin which contains one or more nuclei in which the p-position to the phenolic oxygen atom is unsubstituted or is substituted by an atom or group which is readily removed during the condensation. The resin may contain carboxylic or sulphonic groups not removed during the condensation, and the dyes may be readily soluble in alkaline developer-solutions, or destroyed or discharged in alkaline developer solutions containing sulphite. The dyes are readily bleached in alkaline sodium hydrosulphite baths. The dyes may be employed in conjunction with other film forming substances, such as coloured or colourless synthetic resins or cellulose derivatives, in particular the mixed resin acids from tall oil, and with plasticizers and other dyes. The antihalation layers are particularly suitable for use with panchromatic emulsions. The resins may be of the following types:- phenol-aldehyde ; phenol-ketone, hydroxypolystyrene and maleic anhydride interpolymers ; mixed condensation product resins derived from phenols, phenoxyacetic acid and formaldehyde ; ketone-aldehyde resins containing phenolic groups in either the ketone or aldehyde residue ; polymerization products of phenolic vinyl compounds, phenolic acrylic acid esters, and phenolic acrylic acid anilides (where the phenolic group is in the anilide residue), e.g. polymerized hydroxystyrene resins; urea-aldehyde resins which contain phenolic groups (derived from phenolic ureas or phenolic aldehydes) ; polymerized isoeugenol resins and related types ; polyvinyl acetals of phenolic aldehydes ; and phenolsugar resins. The resins may contain substituent alkyl or nitro groups or halogen atoms. The resins may be obtained by condensing phenol and formaldehyde ; phenol and acetaldehyde; phenol and sucrose; p-hydroxybenzoic acid and formaldehyde ; phenol, formaldehyde, and mono-chloracetic acid ; 2-hydroxystyrylmethylketone and formaldehyde ; α-naphthol and benzaldehyde; phenol and acetone; salicylic acid and formaldehyde ; salicylaldehyde and polyvinylalcohol; phenol and methylstyrylketone; and salicylaldehyde and acetophenone. Resins obtained by polymerizing single substances such as 2-hydroxystyrylmethylketone may be used. The dyes may be dissolved in ethyl alcohol acetone, or ethyleneglycol monomethyl ether and coated as a layer. In examples, (1) a solution of the dye from N : N-diethyl-p-phenylenediamine hydrochloride and a phenol-formaldehyde resin in ethyl alcohol and ethyleneglycol monoethyl ether is coated as an antihalation layer on the opposite side of glass or film base to a panchromatic emulsion ; (2) a solution of the dye from p-nitrosodimethylaniline and a phenolformaldehyde resin in acetone and ethyleneglycol monoethylene ether is coated on the opposite side of glass or film base to a panchromatic emulsion ; (3) a solution of the dye from p-nitrosodimethylaniline and a p-hydroxybenzoic acid formaldehyde resin in ethyl alcohol and ethyleneglycol monoethyl ether is coated on the opposite side of a film base to a panchromatic emulsion; and (4) a solution containing the dye of example (2) and the mixed resin acids from tall oil in ethyl alcohol and ethylene glycol monoethyl ether is coated on the opposite side of a film base to a panchromatic emulsion. Specification 540,382, [Group XX], is referred to. The synthetic resins are produced as follows: (1) A mixture of p-hydroxybenzoic acid, formaldehyde, ammonium chloride, and water is refluxed for 21 hours, and the white solid obtained heated at 150‹ C. with stirring. After cooling, the resin is dissolved in aqueous sodium carbonate solution, and re-precipitated by addition of dilute acid. (2) The ammonium chloride is replaced by hydrochloric acid and refluxing effected for 3¢ hours. (3) Phenol, formaldehyde, and hydrochloric acid are heated together on a water bath for 2 hours, the solution boiled for 15 minutes and allowed to stand for 12 hours, and the resin washed and dried. (4) The resin (3) is dissolved in aqueous caustic soda and mixed with aqueous monochloracetic acid. After heating on a water bath for 1 hour the resin is precipitated by acidification, re-dissolved, and re-precipitated. (5) An acidified mixture of phenol and acetaldehyde is heated on a water bath for half an hour, and allowed to stand overnight, after which the resin is dissolved and re-precipitated. (6) A mixture of 2-hydroxystyrylmethylketone and formaldehyde is treated with caustic soda and refluxed for 1¢ hours before evaporating to dryness. The residue is dissolved and the resin precipitated by acid. (7) A mixture of α-naphthol, benzaldehyde, ethyl alcohol, and concentrated sulphuric acid is heated on a water bath for 20 minutes and poured into water. The precipitate is dissolved and re-precipitated. (8) A mixture of phenol, acetone and sulphuric acid is refluxed on a water bath for 2 hours and then on an oil bath for 2 hours at 130-140‹ C. The resin is dissolved, filtered, reprecipitated, and extracted with ether. (9) A mixture of m-hydroxybenzoic acid, formaldehyde, and concentrated hydrochloric acid is refluxed for 12 hours. (10) A mixture of polyvinyl alcohol, salicylaldehyde, glacial acetic acid, and 85 per cent. phosphoric acid is stirred mechanically for 6 hours at 60-70‹ C., and the product poured into dry ethyl alcohol. (11) A mixture of polyvinyl alcohol, m-hydroxybenzaldehyde, glacial acetic acid, andphthalaldehydic acid is stirred for 20 hours at 60-70‹ C., and the product is stirred into water. (12) Nitropolystyrene, prepared by the nitration of polystyrene with nitric acid is reduced by heating with ethyleneglycolmonomethyl ether, tin, and hydrochloric acid, and after repeating the reduction twice the product is boiled and poured into ether and acetone to precipitate aminopolystyrene. The latter is diazotized and heated until no more nitrogen is evolved, and the resin is dissolved and re-precipitated. Indoaniline dyes are prepared by dissolving the phenolic resins in the minimum quantity of caustic soda solution, adding aqueous sodium acetate solution, and cooling to 0‹ C. To this solution are added gradually over a period of one hour aqueous solutions of an aromatic p-diamine salt and sodium hypochlorite. After stirring, the dye is filtered off, washed and dried in vacuo, and may be purified. In a second method, the aromatic p-diamine salt is added to the resin solution, and after warming to 40-50‹ C. an aqueous solution of potassium di-chromate is added during “ hour, and after a further “ hour, the dye is precipitated by acidification. In either method, the p-diamine may be prepared in situ by the reduction of the corresponding nitrosamine salt in aqueous solution with zinc dust. The dyes may be prepared from N : N-diethyl-p-phenylenediaminehydrochloride or p-nitrosodimethylaniline. Benzthiazine dyes are prepared by refluxing the indoaniline dyes or their leuco derivatives with sodium polysulphide solution in dry ethyl alcohol for several hours, cooling, and filtering. In an example a mixture of sulphur, sodium sulphide, and ethyl alcohol is refluxed on a water bath to give an alcoholic sodium polysulphide, which is then mixed with the dye (1) above, and the resulting mixture is refluxed for 6 hours, allowed to stand, and filtered. The dye is purified by extraction with ethyl alcohol. Indophenol dyes may be prepared by the first method given for indoaniline dyes above, substituting a p-aminophenol for the p-diamine salt. In examples, (1) the resin (3) above and p-aminophenol hydrochloride are mixed together and oxidized. The leuco-dye is obtained by acidification and purified by boiling with dry ethyl alcohol and animal charcoal. The leuco dye may itself be coated as a layer and oxidized by treatment with alkali hypochlorites, or by incorporating piperidine, triethanolamine, or a metalhydroxide in the coating solution. (2) The resin (1) above and p-aminophenolhydrochloride are mixed together and oxidized. The leuco dye is oxidized by treatment with sodium hypochlorite solution.