Photochromic material containing a spiropyran compound a polyhalogenated hydrocarbon photoactivator and an acetanilide sensitizer and the use thereof in photoimaging

Abstract

Abstract Spiropyran compounds suited for photographic image formation according to the present invention are spiropyrans containing at least one pyran ring having in the ortho- and meta-position to the oxygen atom a condensed benzo, naphtho or other higher aromatic polycyclic condensed ring system including these condensed rings or ring systems in substituted state e.g. an anthraceno or a phenanthreno ring system e.g. as present in a spirodibenzopyran, a spirodinaphthopyran, a spirobenzonaphthopyran, a 1,3,3-trimethylindolinobenzospiropyran, a 1,3,3-trimethylindolinonaphthospiropyran or such spiropyrans containing condensed aromatic nuclei of the anthracene or phenanthrene type. In said spiropyrans the pyran rings, the condensed benzo, the condensed higher aromatic rings as well as the 1,3,3trimethylinodolino ring may be substituted. Suitable substituents therefore are e.g. hydrocarbon groups such as alkyl groups, e.g. lower alkyl groups such as methyl, substituted alkyl groups e.g. halogen, or phenyl substituted alkyl groups, alkylene ester groups e.g. a -CH2-COOC2H5 group, alkylene carboxyl groups e.g. a -CH2-COOH group, carbonamide groups or substituted carbonamide groups e.g. a group in which each of R3 and R4 represent an alkyl group or an aryl group e.g. a phenyl group including these groups in substituted form, and R2 represents hydrogen or an organic group e.g. an alkyl group, an aryl group e.g. phenyl group or a heterocyclic group including these groups in substituted form. Preferred sensitizing agents according to the above general formula are acetanilide and acetanilide derivatives. Examples of useful sensitizing agents according to the general formula are listed in the following Table 1. wherein: R1 represents an organic group e.g. of the type present in a carboxylic acid chloride e.g. an alkyl group, an aryl group or heterocyclic group including these groups in substituted form, or a -NHR3 or In order to illustrate in more details the preparation of the diarylo spiro-pyran compounds and the indolino-arylospiropyran compounds the following preparation receipts are given: Preparation 1 Preparation of 3-methyldi- Beta -naphthospiropyran (compound 2 of Table 2) In a 2 litre three-necked flask, fitted with a reflux condenser and a gas inlet tube reaching nearly the bottom of the flask are introduced: The flask is shaken until partial dissolution of the ingredients. Dry hydrogen chloride gas is introduced at a rate, which allows complete absorption and the start of ethanol reflux. Thereupon the already highly blue coloured mixture is cooled down in a mixture of ice and sodium chloride and the introduction of hydrogen chloride gas is continued until saturation. In the reaction mixture green crystals of pyrylium salt are formed and the crystallization is allowed to proceed overnight in a refrigerator. The pyrylium salt formed is separated by suction, is washed with ethanol, and thereupon suspended in 300 ml of ethanol. Whilst stirring a 10 percent by weight aqueous solution of ammonium hydroxide is added until the mixture is definitely alkaline. During this operation the mixture becomes colourless. The obtained crystalline product is separated by suction, washed with water, and dried. Finally the spiropyran compound is recrystallized from 600 ml of benzene, separated again, and dried under reduced pressure at 50*-60*C. Yield: 45 g. Melting point: 204*C. Preparation 2 Preparation of 1,3,3-trimethylindolinobenzopyrylospiran (compound 22 of Table 2) In a 100 ml flask fitted with a reflux condenser the following ingredients are introduced: The solution is refluxed for 2 hours, whereupon the mixture is cooled and filtered. Water is added to the filtrate. The solid is then separated by suction, washed with water, and dried in vacuo. The spiran compound is recrystallized from 15 ml of hexane. Yield: 5 g. Melting point: 93*-94*C. For use according to the present invention the compound capable of producing a dye salt with a spiropyran on exposure to activating electromagnetic radiation is preferably an organic polyhalogen compound, from which a halogen-containing radical can be separated photolytically. Compounds possessing this property are within the scope of the following general formula: wherein: each of A, B, X, and Y are halogen atoms of the group of chlorine, bromine, or iodine, or wherein one of said groups A, B, X, or Y represents an alkyl group, including a substituted alkyl group e.g. a halogen substituted alkyl group, a hydroxyalkyl group or an aralkyl group e.g. a benzyl group, an aryl group, a substituted aryl group or an aroyl group and the other groups chlorine, bromine, or iodine, or wherein at least two of said groups A, B, X, or Y represent an aromatic acyl group e.g. a benzoyl group and the other groups chlorine, bromine, or iodine. Suitable representatives falling within the scope of the general formula are organic halides such as carbon tetrabromide, GROUP IN WHICH EACH OF R3 and R4 represent an alkyl group or an aryl group, and R2 represents hydrogen, or an organic group. This invention relates to photographic recording and reporduction of information and to materials suited therefor. The use of particular spiropyrans in the manufacture of photographic recording materials is known e.g. from the U.S. Pat. No. 2,953,454 of E. Berman - Nat. Cash Reg., issued Sept. 20, 1960. The spiropyrans described therein are characterized as being reversibly transformable into a coloured form by activating electromagnetic energy. In many applications such reversible transformation is not desirable and therefore efforts have been made to obtain a printout colour image, the colour of which does not fade by keeping it in the dark or by a further irradiation with electromagnetic radiation differing in wavelength from the radiation originally applied. In the German Patent Specification No. 1,274,655 filed Dec. 15, 1965 by Telefunken Patentverwertungs G.m.b.H. a recording material has been described by means of which stable print-out dyestuff images can be obtained by using spiropyrans in admixture with a compound that activated with electromagnetic radiation can yield photolytically formed free radicals. The starting substances for these radicals are preferably halogenated organic compounds. The recording materials described in the latter Patent Specification need rather long exposure times with the conventional ultra-violet radiation sources. It is an object of the present invention to provide a method for increasing the photosensitivity of recording materials containing a photosensitive compound that by information-wise exposure to activating electromagnetic radiation yields a dyestuff image by reaction with a spiropyran compound. It is another object of the present invention to provide a method for making visible or intensifying a latent image or barely visible image produced with said spiropyran and photosensitive compound. Said method is called hereinafter ''''optical development'''' for it operates with an overall exposure in the wavelength range of electromagnetic radiation absorbed by dyestuff traces formed in the imaGe-wise exposure. It is a further object of the present invention to provide photographic materials suited for use in said methods. It has now been found that the photosensitivity for forming a directly visible image or optical development sensitivity of a recording material containing in intimate admixture: 1. at least one spiropyran compound, and 2. at least one ultra-violet radiation-sensitive compound capable of producing an exposure to ultraviolet radiation with said spiropyran compound a dyestuff salt, is increased by using in working relationship with said mixture an organic compound being: an amido, acylamino or ureido compound corresponding to the following general formula: WHEREIN: R1 represents an organic group of the type present in a carboxylic acid chloride, a -NHR3 or a A photographic process wherein a visible image is formed in a recording material which comprises in intimate admixture: 1. AT LEAST ONE SPIROPYRAN COMPOUND, 2. AT LEAST ONE ULTRA-VIOLET RADIATION-SENSITIVE COMPOUND CAPABLE OF PRODUCING ON EXPOSURE WITH ULTRA-VIOLET RADIATION WITH THE SPIROPYRAN COMPOUND A DYE SALT, AND IN WORKING RELATIONSHIP WITH SAID MIXTURE AN ORGANIC COMPOUND, WHICH IS AN AMIDO, ACYLAMINO OR UREIDO COMPOUND CORRESPONDING TO THE FOLLOWING GENERAL FORMULA: wherein: R, R1, R''1, R2, R''2, R3 and R''3 represents hydrogen, an aliphatic group including a substituted aliphatic group e.g. a (C1-C20) alkyl group including such an alkyl group in substituted form, more particularly a methyl, ethyl, propyl, amyl, or hexadecyl group or halogen substituted alkyl group, halogen, nitro, hydroxy, an alkoxy or aryloxy group, a phenyl group, or a substituted phenyl group, piperidyl, an alkylene ester group e.g. a -CH2-COOC2H5 group, an alkylene carboxyl group e.g. a -CH2-COOH group, a carbonamide group or a substituted carbonamide group e.g. a group, or R1 and R''1 together represent a -(CH2)n-chain wherein n 2 or 3 to link the carbon atoms in the 3 and 3'' positions. Suited spiropyran ompounds and their preparation are described in the published German Patent Applications 1,274,655 filed Dec. 15, 1965 by Telefunken Patentverwertungs G.m.b.H., 1,269,665, 1,286,110, 1,286,111 and 1,286,112 all filed Sept. 30, 1966 by Telefunken Patentverwertungs G.m.b.H., and by W. Dilthey, Berres, Holterkoff, Wubken, J.Pr.Ch. (2) 114, 187 (1926), by C. F. Koelsch and W. R. Workman in J.A.C.S. 74 6288 (1952) and in J.Chem.Soc. (1934), 1571 by I. M. Heilbron and G. F. Howard. Preferred spiropyran compounds are spirodinaphthopyrans and spirobenzonaphthopyrans including such compounds wherein the naphtho- and/or benzo ring(s) is (are) substituted. An illustrative list of particularly useful spiropyran compounds is given in the following Table 2. group, halogen, nitro, hydroxy, alkoxy, aryloxy or a substituent linking the carbon atoms in 3,3''-position in the spiropyran system together e.g. a (CH2)n-chain wherein n is 2 or 3. General formulae covering particularly suited spiropyrans are the following:

Inventors

• 👤 Royen F Van
• 👤 L Mertens
• 👤 Den Houte J Van

Bibliographic Details