Patent GB-545529-A (GB)
Title: Improvements in or relating to photographic materials
IPC: C08G14/06
Filed: 1940-11-29
Abstract: 545,529. Diazotized phenolic resins; azo dyes. COLLINS, R. B. Nov. 29, 1940, Nos. 17033/40 and 741/41. [Class 2 (iii)] [Also in Group XX] Light sensitive photographic materials comprise anti-halation or filter layers consisting essentially of thin layers of azo dyestuffs of resinous character obtained by coupling a diazotized aromatic amine with a synthetic phenolic resin containing one or more nuclei in which positions o- or pto the phenolic group are unsubstituted or are substituted by atoms or groups, e.g. halogen atoms or carboxylic or sulphonic acid groups, which are readily removable in the coupling reaction. Specified phenolic resins are those of the phenol-formaldehyde, phenol-acetaldehyde, .1-naphthol-benzaldehyde, phenol-ketone, e.g. phenol-acetone or phenolstyryl methyl ketone or hydroxypolystyrenemaleic anhydride interpolymer types, condensation products from phenols, phenoxy-acetic or monochloracetic acid and formaldehyde, ketonealdehyde resins containing phenolic groups, e.g. that from 2-hydroxy styryl methyl ketone and formaldehyde or from salicyl-aldehyde and acetophenone, polymerisation products of phenolic vinyl compounds, e.g. polymerized 2- hydroxystyryl methyl ketone, phenolic acrylic acid esters and phenolic acrylic acid anilides, urea-aldehyde resins containing phenolic groups, polymerised isoeugenol resins, polyvinyl acetals of phenolic aldehydes, phenol-sugar' resins, condensation products of phenol and formaldehyde with a polyhydric alcohol, e.g. glycol, glycerol or sugar, and the condensation product from salicyl-aldehyde and polyvinyl alcohol. Specified phenols used for preparing the resins are phenols, cresols, xylenols, ethyl phenols, resorcinol, pyrogallol, phloroglucinol, 1-naphthol and its sulphonic acids, salicylic and phenol-osulphonic acid, m- or p-hydroxybenzoic acid and chlorophenols. Varying intensity of colour of the azo dyes used may be obtained by varying the relative proportions of the diazo component and the phenolic resin coupling component. Examples are given of the preparation of the resins to be used from (1) p-hydroxybenzoic acid and formaldehyde by refluxing for 21 hours in aqueous solution containing ammonium chloride, separating the product which solidifies on cooling, heating it for 2 hours at 150‹C, dissolving in sodium carbonate solution and reprecipitating with dilute hydrochloric acid ; (2) p-hydroxybenzoic acid and formaldehyde by refluxing for 3¢ hours in aqueous solution containing hydrochloric acid, filtering off and washing the product (3) m-hydroxybenzoic acid and formaldehyde by refluxing for 12 hours in aqueous solution containing hydrochloric acid and filtering off the product ; (4) phenol and hexamethylenetetramine by heating together for 3 hours at 180‹-190‹C., cooling, washing and drying the product; (5) phenol, formaldehyde and sugar by heating for 1 hour on a water bath in aqueous solution containing caustic soda, further heating for 2 hours under reflux and washing and drying the product ; (6) phenol and formaldehyde by heating for 2 hours on a water bath in aqueous solution containing hydrochloric acid, boiling for 15 minutes, allowing to stand for 12 hours, decanting the upper aqueous layer and washing and drying the residue ; (7) sodium 1-naphthol-4-sulphonate and formaldehyde by refluxing for 3 hours the aqueous solution acidified with acetic acid, filtering off, washing and drying the product, heating for 35 minutes at 140‹C. and then for 10 minutes at 160‹C. and purifying by extraction with alcohol ; (8) phenol and acetaldehyde by adding cone. hydrochloric acid to a mixture of the reagents, heating for ¢ hour on a water bath, allowing to stand overnight, extracting with aqueous caustic soda, filtering the solution and re-precipitating by adding conc. hydrochloric acid ; (9) 2-hydroxystyryl methyl ketone and formaldehyde by refluxing for 1¢ hours in aqueous solution containing caustic soda, evaporating to dryness, extracting with hot water, filtering the solution and re-precipitating by addition of hydrochloric acid; (10) 2-hydroxystyryl methyl ketone by heating for 3 hours on a water bath in an acetone solution containing piperidine and evaporating to dryness ; (11) 1-naphthol and benzaldehyde by admixing with alcohol, adding conc. sulphuric acid, heating for 20 minutes on a water bath, pouring into water, filtering, dissolving in alcohol, pouring into water and separating and drying the precipitate ; (12) phenol and acetone by adding conc. sulphuric acid, refluxing on a water bath for 2 hours and then at 130-140‹C. on an oil bath for 2 hours extracting with aqueous caustic soda, reprecipitating with hydrochloric acid and purifying by extraction with ether ; (13) phenol and acetone by adding conc. hydrochloric acid, heating to 40‹C., allowing to stand for 12 hours, refluxing for 2 hours and evaporating to dryness; (14) salicylaldehyde and polyvinyl alcohol by adding glacial acetic and conc. phosphoric acid, stirring the mixture for 6 hours at 60-70‹C., pouring into alcohol, filtering off the product and washing it whith alcohol; (15) m-hydroxybenzaldehyde, phthalaldehydic acid and polyvinyl alcohol by adding glacial acetic acid, stirring the mixture for 20 hours at 60‹-70‹C., extracting with water, filtering and drying; (16) polystyrene by conversion into hydroxypolystyrene by successively nitrating, reducing the nitro group, diazotizing the resulting amino polystyrene and warming the aqueous solution of the diazonium chloride. The diazo compounds may be coupled with the phenolic resins so obtained either in aqueous caustic soda or in alcohol or glacial acetic acid containing an excess of sodium acetate or (especially in the case of insolubility of the resin in alkali or acetic acid) in pyridine. A table given showing the colour and solubility characteristics of the dyestuffs from various diazotized components in defined proportions with various resins prepared as above, specified diazo components being aniline, o-toluidine, o- and p-nitranilines, sulphanilic acid, anthranilic acid, p-aminobenzoic acid, p; p<SP>1</SP>-diaminostilbenes disulphonic acid, p-diethylaminoaniline, 1-naphthylamine and 1 : 2 : 4-aminonaphtholsulphonic acid. More highly condensed dyestuffs may be obtained by subjecting the products to a heat treatment, e.g. at 140-160‹C., for 1 hour or to further condensation with formaldehyde, e.g. by heating with bexamethylenetetramine at 150-160‹C. for 1 hour or by boiling for 2 hours in aqueous solution containing formaldehyde and hydrochloric acid. In an example of the preparation of an orange anti-halation layer a dyestuff obtained by coupling the diazo compound from 1 part of anthranilic acid with 3 parts of resin (12) above is dissolved in ethyl alcohol containing ethylene glycol monoethyl ether and the solution is used to coat one side of a photographic film support of which the other side is coated with an orthochromatic emulsion.