US3782943A - Process for the formation of image polymers - Google Patents

Abstract

A PROCESS FOR FORMING IMAGES INVOLVING POLYMERIZING AT LAST ONE ADDITION POLYMERIZABLE VINYL COMPOUND IN A PHOTOGRAPHIC SILVER HALIDE EMULSION LAYER CONTAINING A PHENOL.

Description

United States Patent Int. Cl. G03c 1768, 1/70, 5/26 US. Cl. 96-48 R 25 Claims ABSTRACT OF THE DISCLOSURE A process for forming images involving polymerizing at least one addition polymerizable vinyl compound in a photographic silver halide emulsion layer containing a phenol.

CROSS-REFERENCE TO RELATED APPLICATION The present application is a continuation of co-pending application Ser. No. 790,457, filed Jan. 10, 1969, now abandoned, claiming priority from Jan. 10, 1968, based on Japanese patent application No. 1,215/ 68.

BACKGROUND OF THE INVENTION Field of the invention This invention relates generally to a process for producing polymer images and, more particularly, to a process for forming a high molecular weight material selectively at the areas corresponding to latent photographic images by the action of a photographic silver halide emulsion and a reducing agent.

Description of the prior art Various processes have been proposed for forming high molecular weight compounds by the photopolymerization of vinyl compounds. Furthermore, it has been proposed to cause direct photopolymerization by using a silver halide catalyst, for example see British Pat. No. 866,631 and S. Levious et al.: Photographic Science & Engineering; vol. 6' 222-226 (1962). However, in the above reaction, it is considered that the product formed by the photodecomposition of silver halide acts directly as a catalyst for the polymerization and hence the reaction is not as sensitive as in the case where silver halide grains are reduced by a conventional developer.

Also, it has been proposed to form images of a high molecular weight compound by developing exposed silver halide emulsion grains in a conventional developer and thereafter conducting the polymerization of a vinyl compound by utilizing the silver image thus formed or the unreacted silver halide as a catalyst (e.g., Belgian Pat. No. 642,477). However, a difiiculty with such a process is that the developing procedure must be conducted separately from the polymerization procedure.

A process in which exposed silver halide grains are developed by a reducing compound in the presence of a vinyl compound and the vinyl compound is polymerized by the oxidation product (or an intermediate product thereof during the development) is very interesting from a theoretical point of view, since, in such a process, the amplification action by both development and by chain polymerization can be utilized. Thus, it has already been proposed to conduct the aforesaid reaction using, as a reducing agent, a so-called benzenoid compound, i.e., a compound having at the ortho or para positions on a benzene ring at least two hydroxyl groups, amino groups, or amino groups substituted by alkyl 3,782,943 Patented Jan. 1, 1974 groups or acyl groups (e.g., US. Pat. N0. 3,019,104, and G. Oster, Nature"; vol. 180, 1275 (1957)).

SUMMARY OF THE INVENTION Thus, an object of the present invention is to provide a process of converting images generated by electromagnetic Waves orparticle rays to the images of high molecular weight material by a simple procedure.

Another object of this invention is to provide a process for obtaining polymer images having the desired properties by utilizing the aforesaid recording process.

The inventors have found that the above-mentioned polymerization of vinyl compound can be caused by reducing a silver halide in the presence of the vinyl compound using an alkyl phenol, a halogenated phenol, an acyl phenol or derivatives thereof.

Moreover, it has been found that when in this case a photographic silver halide emulsion is used as the silver halide, the reaction occurs more rapidly when the fine crystals of silver halide contain the development nuclei and, accordingly, when the reaction is conducted under suitable conditions and for a suitable period of time, the polymerization can be selectively induced only in the areas where silver halide particles having the development nuclei are present.

DESCRIPTION OF THE INVENTION The present invention can be attained by utilizing aforesaid facts. That is, the process of the present invention can be achieved by reacting at least one of the phenols represented by the following formula with a wherein R R R R and R satisfy one of the follow-.

ing conditions:

(a) R represents a methyl group, a hydroxymethyl group, a dialkylaminomethyl group, a bromomethyl group, a carboxymethyl group, a carboxyl group or an acyl group; R and R each represents a hydrogen atom or an alkyl group, preferably of from 1 to 4 carbon atoms; R represents a hydrogen atom, or an alkyl group, preferably of from 1 to 8 carbon atoms or a halogen atom; and R represents a hydrogen atom, an alkyl group, preferably methyl, a hydroxymethyl group or a halogen atom; said R and said R may form a naphthalene ring by ring condensation.

(b) R and R each represents a hydrogen atom or a halogen atoms; R and R, each represents a hydrogen atom or an alkyl group, preferably of from 1 to 4 carbon atoms, and R represents an alkyl group, preferably of from 1 to 8 carbon atoms, an aralkyl group, a substituted alkyl group, or a halogen atom; said R and K, may form an alkylene ring by ring condensation, and when doing so R and R have from 1 to 6 carbon atoms, said R may be an alkylene group to form a bisphenol.

(c) R represents a tertiary alkyl group, preferably a tertiarybutyl group, and the other Rs represent a hydrogen atom.

A latent photographic image is formed in a photographic silver halide emulsion layer by light-exposure orbecomes visible when developed. In an emulsion layer forming a usual negative image, the formation of a latent image is accomplished by the formation of development centers on the silver halide grains which are irradiated by light or high energy rays. On the other hand, in an emulsion layer for direct positive image, the latent image is formed by forming development centers first on every silver halide grain and afterwards destroying the development centers by the irradiation of light or high energy rays (see: James & Huggins; Fundamentals of Photographic Theory, 2nd ed., Morgan & Morgan Co., 1960).

As the silver halide photographic emulsion used in the present invention, any silver halide emulsion for forming a negative image by development and any silver halide emulsion for forming direct positive images may be employed effectively.

As the silver halide used in the photographic silver halide emulsion for forming negative images by development, there may be employed silver chloride, silver bromide, silver chlorobromide, silver iodobromide, or silver halide emulsion used in this invention may be subjected to chemical sensitization and optical sensitization usually employed for photographic silver halide emulsions. That is, the photographic silver halide emulsion may be subjeeted to sulphur sensitization and noble metal sensitization as the chemical sensitization, for example see P. Glafkides; Chimie Photographique, 2nd ed., pp. 247- 301 (1957), Photocinema Paul Montel, Paris, and may be subjected to cyanine dye sensitization or merocyanine dye sensitization as the optical sensitization. Also, the photographic silver halide emulsion used in this invention may contain a stabilizer usually employed in photographic techniques.

The photographic silver halide emulsion for direct positive images used in the present invention may be prepared by utilizing selarization, a Herschel effect, a Clayden effect, or a Sabattier effect. These effects are described in, for example, C. E. K. Mees; The Theory of Photographic Process, 2nd ed., pars. 6 and 7, McMillan Co. (p. 954). In order to prepare the photographic silver halide emulsion by utilizing solarization, a light sensitive layer of a photographic silver halide emulsion susceptible to solarization is prepared, and is light-exposed or treated with a chemical to such extent that the layer can be sufficiently developed without subjecting it to an image exposure. The production of such a kind of photographic silver halide emulsion is disclosed, for example, in British Pats. 443,245 and 462,730.

The Herschel effect is caused by the exposure to long Wave length light of a silver halide which has been provided with developability wholly by overall exposure or chemical treatment. In this case, it is profitable to employ a silver halide emulsion containing a large amount of silver chloride, and also a desensitizing dye such as pinakryptol yellow and phenosafranine is frequently incorporated in the emulsion to promote the occurrence of the Herschel effect. The production of the photographic silver halide emulsions for direct positive images by utilizing the Herschel effect is disclosed in, for example, British Pat. 667,206 and U.S. Pat. 2,857,273.

In order to prepared the photographic silver halide emulsion layer for direct positive images by utilizing the Clayden effect, it is necessary to expose the emulsion layer intensely through an image for a short period of time and thereafter weakly expose the whole surface of the emulsion layer. By the latter overall exposure, the areas of the emulsion layer which had not been subjected to intense image exposure are endowed with developability.

The Sabattier effect occurs when a silver halide emulsion layer is image-exposed and thereafter uniformly exposed while being immersed in a developer or treated with a chemical, whereby the areas of the emulsion layer which had not been image-exposed become developable.

The Clayden effect, as well as the Sabattier effect, occur easily in practice when using a silver halide emulsion which tends to form development nuclei more in the inner parts of the grains of silver halide than on the surface of the grains by the first exposure. The production of a silver halide emulsion capable of easily forming internal development nuclei is described in the specifications of U.S. Pats. 2,592,250 and 2,497,876, British Pat. 1,011,062 and German Pat. 1,207,791.

The photographic emulsion mentioned above is prepared by dispersing silver halide grains in a solution of a high molecular weight material. As the high molecular weight material, gelatin is most frequently used, but a synthetic high molecular weight compound such as polyvinyl alcohol, polyvinyl pyrrolidone, or polyacrylamide, or a derivative of a natural high molecular weight compound such as carboxymethylcellulose, cellulose oxyethyl ether, or dextran may be used alone or together with gelatin. (See, for example, F. Evva; Zeitschrift fur Wissenschaftliche Photographic, Photophysik und Photochemic; vol. 52, l-24 (1957).)

The typical examples of the phenols represented by the General Formula I are shown below:

CH3 H3C-(:J -CH3 p-eresol 4-t-butylpheuol 3. (|)H 4. 11

/CH3 mo CH:

CH2 CH3 3-tbutylphenol 4-sec-butylphenol 5 0H 6. (|)H /CH3 Q HAD-(i l CH R 4-t-amieophenol 4-t-octyl-phenol H2 p-b euxylphenol orthoxylenol HO- cru on. CH3

CH1 5-hydroxhydrindene 5,6,7,8,-tetrahydro-B-naphthol CH; CH;

(E CH; CH;

H O H H30 CH3 HsC CH 3-methyl-4-isopropylpheno1 3-butyl-4-isoprop ylphenol 2 O OH p-hydroxyphenylacetic acid 3-lodosalieyllc acid 37. CODE fi-iodosalicylic acid (I) H @CHS orthocresol on Uomon 2-hydroxymethylphenol Z-aeetyl-l-naphthol CzHs CHg-N 2-(N,N-diethylamlnomethyl)-1-napthol orthohydroxyphenylacetic acid The compounds mentioned above may be prepared by well known methods and may be commercially available. In the present invention, a silver halide is used in the form of a photographic silver halide emulsion as mentioned before increasing the difference of the reactivity between the portions exposed to electromagnetic waves or particle rays and the unexposed portions, that is, the selectivity of reaction.

There are many reports concerning the oxidation of the phenols and the intermediate products thereof, e.g., Chemical Review; 58, 439 (1958) and ibid.; 61, 563 (1961). Also, attempts have been made to form polymers by subjecting phenols to oxidation coupling and there are many reports thereon, e.g., A. S. Hay; Journal of American Chemical Society; 58, 581 (1962) and C.

C. Price; Journal of American Chemical Society; 82, 3632 (1960). Furthermore, there are many reports regarding studies of intermediate products by the oxidation of phenols using electron spin resonance spectra (e.g., W. A. Waters; Journal of Chemical Society 2823 (1956); Proc. Chemical Society; 253 (1962) and Chemical & Industry; 213 (1964) From these results the electron density of the phenoxy radicals formed by the oxidation has been investigated and the spin density on the benzene ring has been determined. In the aforesaid reports, iron salts, cerium salts, and oxygen-copper salt pyridine are the main oxidants used. However, in these reports, no attempts to polymerize a vinyl or vinylidene monomer utilizing the phenoxy radical formed by the oxidation are reported.

The reaction mechanism of initiating the polymerization of a vinyl compound as the result of the reduction of a silver halide by the aforesaid compound, represented by the General Formula 1, has not yet been clarified, but it is generally thought that the polymerization proceeds by a radical mechanism since a compound capable of conducting radical polymerization can generally be utilized, the reaction proceeds in an aqueous solution, and the use of a radical polymerization inhibitor retards the reaction. Furthermore, it has not yet been clear whether the radical is formed directly by the reaction of a silver halide and the compound represented by General Formula 1 or the radical is formed by the interaction of water, oxygen, etc., in the system. However, although the influence of oxygen is not clear from the aforesaid reports, it is considered that following reaction may occur:

OH O- O l i I-A. LB 1- Furthermore, the resonance shown below is assumed in the radical formed and it is considered that the resonnance hybrid contributes to the start of polymerization- 0 0 0 I I Z R R R Also, when the exposed silver halide is reduced by the compound represented by the General Formula 1 and thereafter a vinyl compound is added to the reaction system, no polymerization is observed. Thus, it is clear that the polymerization of the vinyl compound occurs at the same time as the silver halide reduction. Therefore, it is considered that the intermediate product of a silver halide and the compound represented by the General Formula 1 contributes to the reaction. Further, when the reaction is stopped in a suitable time, a high molecular weight compound is selectively formed at only the portions exposed, but when the reaction is allowed to continue further, the high molecular weight compound is formed at the non-exposed portions. This fact must be due to the dilference in rate of formation of (l-C) caused by the difference in reactivity between the exposed silver halide grains and the unexposed ones. However, the phenomenon that when the reaction is continued for a long period of time the diiference in reactivity between the exposed portions and the non-exposed portions disappears is similar to so-called fogs. That is, a phenomenon that when a usual photographic light-sensitive emulsion layer bearing an exposed image is developed for a long period of time, even the unexposed portion is developed to form black silver, and hence the utility of the present invention is not spoiled.

As a method of forming an image of a high molecular weight material by utilizing the light-sensitivity of silver halide, there is known the so-called tanning development where gelatin is cross-linked by the oxidation product of a well known developer, but in this process the material forming the image is limited to only the cross-linked product of the gelatin. However, in the process of this invention, images of high molecular weight compounds having various properties may be prepared in accordance I with the vinyl compounds employed and, therefore, images having very excellent properties, such as dyeing property, and chemical resistance, which have never been attained with the cross-linked product of gelatin, can be obtained.

Furthermore, we have also found that if sulphite ions are present in the reaction system in this invention, the polymerization of the vinyl compound can be accelerated.

Sulphite ions may be added to the reaction system, either in the form of a compound which originally contained the sulphite ion in the molecule, such as alkali metal sulphites or ammonium sulphite, or in the form of a compound which will give a sulphite ion as the result of hydrolysis, such as pyrosulphites of alkali-metals and ammonium or the adducts of bisulphites with aldehydes such as formaldehyde or glyoxal. Although the appropriate amount of sulphite ion to be added depends upon the nature and amount of the reducing agent, and the vinyl monomer being used, the pH of the system, and other factors, more than 0.05, particularly more than 0.2 mol per liter of the system is effective.

'It is commonly known in the art to add a sulphite in photographic developing solutions, and in such cases it is believed that the sulphite prevents auto-oxidation of a developing agent and uneven development by reacting with the oxidation products of the developing agents, such as hydroquinone or p amino-phenol. See, for example, C. E. K. Mees Theory of the Photographic Process, the second edition, page 652, published by McMillan Company in 1954. It should be noted that since the intermediate product of oxidation of phenols by silver halide initiates polymerization of the vinyl compound or compounds in the process of the present invention, the polymerization promoting effect of sulphite ion is essentially different from the action of removing oxidation products, as in the ordinary developing solutions mentioned above. The polymerization would be inhibited rather than promoted if the sulphite simply removes the oxidation products as in conventional developing processes. While the mechanism of the action of sulphite ion in the process of the present invention is not clear, it may be that the sulphite ion prevents the polymerization inhibiting action of free oxygen.

The vinyl compounds used in the present invention are addition-polymerizable compounds which are liquid or solid at normal temperatures or mixtures thereof. Illustrative of such vinyl compounds are acrylamide, acrylonitrile, N-hydroxymethyl, acrylamide, methacrylic acid, acrylic acid, calcium acrylate, methyl methacrylate, sodium acrylate, methacrylamide, methyl acrylate, ethyl acrylate, vinyl pyrrolidone, vinylmethyl ether, vinylbutyl ether, vinylisopropyl ether, vinylisobutyl ether, vinyl butyrate, 2-vinylpyridine, 4-vinylpyridine, 2-methyl-N- vinyl imidazole, potassium vinylbenzene sulfonate, and vinyl carbazole.

In the process of this invention, vinyl compounds having more than two vinyl groups are particularly suitable, and such compounds may be used together with the aforesaid vinyl compound having one vinyl group or may be used alone. Examples of such vinyl compounds having a plurality of vinyl groups are N,N-methylene-bis-acrylamide, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, divinyl ether and divinyl benzene.

The present invention, water-soluble vinyl compounds are conveniently used but water-insoluble vinyl compounds may also be polymerized by adding them to the reaction system in the form of an emulsion. The emulsification of such water-insoluble vinyl compounds may be conducted by means of a suitable stirrer in the presence of a surface active agent and/or a high molecular weight compound according to conventional methods.

In the process of the present invention, any electromagnetic waves or particle rays to which usual photographic light-sensitive emulsions are sensitive can be utilized. That is, visible rays, ultra-violet rays, infrared rays having wave lengths shorter than 1.3 microns, X-rays, gamma rays, alpha rays, and electron rays all may be used.

In carrying out the process of the present invention, it is necessary to conduct the step of irradiation by electromagnetic waves or particle rays and the step of reduction and polymerization. Particularly in the recording of images, it is necessary that the silver halide grains change their locations only slightly during the period between the irradiation by electromagetic Waves or particle rays and the polymerization in the reaction system and, accordingly, it is preferable that the system be maintained in a highly viscous liquid or in a gel state. While photographic emulsions have some viscosity and are susceptible to gelling, since they contain natural or synthetic high polymers, some high polymers may be added to the emulsion before use, if necessary.

On irradiation by electromagnetic rays or particle rays, the silver halide grains may be dispersed in an aqueous solution or held in a dry gel. Thus, a highly viscous or gelled photographic emulsion on a suitable support or substrate may be subjected to the irradiation, either in an undried state or a dried state. As the reduction and polymerization take place concurrently, the reduction should be conducted in the presence of a vinyl compound or compounds. While in the present invention, either the vinyl compound or the compound represented by the General Formula 1 may be incorporated in the photographic emulsion before exposure, but only one of them may be so incorporated, the other being added to the system after the exposure. It is also possible to add both compounds after exposure.

As the reduction and polymerization must be conducted in the presence of water, it is necessary to conduct the reduction and polymerization in an aqueous solution or in a wet gel.

In general, the reaction is conducted in the presence of a suitable quantity of an alkali, as it proceeds smoothly under alkaline conditions. While the amount of alkali suitable for the reaction depends on the kind of silver halide, reducing agent, and high polymer in the system, their concentrations, and the reaction temperature, it is preferable to use an amount suflicient to make the pH of the system 6 or more preferably higher than 7. In cases where the photographic emulsion is used in the form of a coated film on a support, the reaction can be performed by immersing the thus-produced photosensitive material in an alkaline aqueous solution after it has been exposed to the electromagnetic waves or particle rays. In this case, the vinyl compounds and/or the reducing agents can conveniently be dissolved in the aqueous alkaline solution.

Although the reaction is stopped readily by adjusting the pH of the system to, for example, 5 or less, it may also be stopped by cooling, removing the reactants by Washing, dissolving the silver halide by fixation, or adding a polymerization inhibitor to the system.

In the case where the high molecular weight polymer, as the vehicle for the silver halide grains, and the monomerie vinyl compound are mixed and coated together to form a film, it is preferable to add a small amount of an inhibitor for thermal polymerization in order to prevent the spontaneous thermal polymerization of the vinyl monomer. As such a polymerization inhibitor any of the known thermal radical polymerization inhibitors, such as p-methoxyphenol, hydroquinones, 2,6-di-tert.butyl-pcresol, or ,B-naphthol, can be used.

When the vinyl monomer is contained in the system from the first, it is incorporated in an amount by weight of from to 30, and preferably from A to 4 times the amount of the high molecular weight polymer which is originally present in the system. The silver halide is conveniently used in an amount by weight of from to 2 and, preferably, to times the amount of the high molecular weight polymer which is originally present in the system. When the reducing agent is to be added to the system before the reaction, it is suitable to add it in the amount of from to 20 moles per mole of the silver halide. It is convenient to add the thermal polymerization inhibitor in an amount of from 10 to 20,000 p.p.m. of the weight of the vinyl compound. In the case where the vinyl monomers are dissolved in the processing solution, it is usually preferable to dissolve them in as high a concentration as possible, and hence the preferable concentration of the monomer is determined mainly by the solubility of the monomer in the solution. In the case where the pyrazolone reducing agents are dissolved in the processing solution, it is suitable to dissolve them in a concentration between and 5 moles per liter, and preferably between and 1 mol per liter.

As with the ordinary silver halide photographic process, there can be any interval of time between the exposure to electromagnetic waves or particle rays and the polymerization step. In some cases, according to the characteristics of the photographic emulsion or the condition and the length of this interval, the effect of the exposure may be diminished to some extent and in this case the decrease in effect can be cancelled by increasing the amount of the exposure.

In the case of applying the process of the present invention to recording images, it is possible to make use of differences in solubility, light scattering, tackiness, dyereceptivity, and other physical and chemical properties between monomeric vinyl compounds and polymers thereof. Relief images of polymeric materials may be formed by dissolving away unpolymerized portions after the irradiation and polymerization, making use of the difference in solubility between the polymerized portions and the unpolymerized portions, so as to leave the thusformed highly polymerized compound, as an image, only the irradiated areas. In this case, it is convenient if the high molecular Weight polymer originally present in the system can be washed away with the unpolymerized vinyl compound. Accordingly, it is preferable that the high molecular Weight polymer originally present in the system be a linear, substantially uncrosslinked one, or such a crosslinked one that is susceptible to chain fission or break-up of the crosslinkage, and that the highly polymerized compound formed by the polymerization of the vinyl compound is a crosslinked one of so-called threedimensional structure. For this reason, it is convenient to employ a compound having a plurality of vinyl groups, as set forth above, either alone, or in combination with a compound having only one vinyl group. It is, however, not essential to employ a compound having a plurality of vinyl groups, since there are many instances where considerable difference exists between the portions containing the high molecular weight substance formed by polymerization of the vinyl compound and the portions not containing such high molecular weight polymeric substance. This is true even if the resulting highly polymerized substance is a linear, soluble one, due to interaction of the highly polymerized substance formed by polymerization and the high molecular weight polymer originally present in the system, as in the case of polyacrylic acid and gelatin.

The image which is made by this procedure and consists of highly polymerized substances can be used in various printing processes.

Furthermore, the process of this invention can be utilized for the formation of color images. In this case, a vinyl monomer having a group capable of having a charge via an electrolytic dissociation or the addition of hydrogen cations is used as the vinyl compound to form a polymer capable of having a charge by electrolytic dis sociation or addition of hydrogen cation, and then the polymer image is selectively dyed by a dye having the opposite charge to that of the polymer. The color images thus formed may be transferred to other supports by various means.

The examples of such addition polymerizable vinyl compounds capable of having a charge by electrolytic dissociation or addition of hydrogen cations used in this invention are as follows: As the monomer capable of providing a negative charge to the high molecular weight compound formed from the monomer, there may be employed vinyl compounds having carboxyl groups, such as acrylic acid, methacrylic acid, itaconic acid, and maleic acid; vinyl compounds containing metal or ammonium salts of carboxyl groups, such as ammonium acrylate, sodium acrylate, potassium acrylate, calcium acrylate, magnesium acrylate, zinc acrylate, cadmium acrylate, sodium methacrylate, potassium methacrylate, magnesium methacrylate, calcium methacrylate, zinc methacrylate, cadmium methacrylate, sodium itaconate, and sodium maleate; vinyl compounds having sulphonic acid groups such as vinyl sulphonic acid and p-vinylbenzene sulphonic acid; and vinyl compounds containing metal or ammonium salts of sulphonic acid, such as ammonium vinyl sulphonate, sodium vinyl sulphonate, potassium vinyl sulphonate, and potassium p-vinylbenzene sulphonate. Also, as vinyl compounds that provide a positive charge to the high molecular weight compound formed from the monomer, there are vinyl compounds having basic nitrogen atoms, such as 2-vinylpyridine, 4-vinylpyridine, 5-vinyl-2- methylpyridine, N,N-dimethylaminoethyl acrylate, N,N- dimethylaminoethyl methacrylate, N,N-diethylaminoethyl acrylate, N,N-diethylaminoethyl methacrylate, and vinyl compounds containing quaternary ammonium salts prepared from a base of the aforesaid vinyl compounds and methyl chloride, ethyl bromide, dimethyl sulphate, diethyl sulphate, or methyl p-toluenesulphonate.

The aforesaid vinyl compounds may be prepared by well known processes, or are easily commercially available. These compounds may be used alone or as mixtures, and may be used together with a water-soluble addition polymerizable vinyl compound having no charge. As the vinyl compound used together with the aforesaid vinyl compounds, there are illustrated acrylamide, N-hydroxymethyl acrylamide, methacrylamide, methyl methacrylate, vinylpyrrolidone, N,N-methylenebis-acrylamide, triethylene glycol dimethacrylate, polyethyleneglycol dimethacrylate and the like.

In the case of employing vinyl compounds having no charge, the reactivity and the proportion of the vinyl compound must be selected so that a high molecular weight compound having substantially no electrolytically dissociating group is not formed as the result of the polymerization of only the vinyl polymer having no charge.

As a dye capable of having a charge by electrolytic dissociation used in this invention, there are generally employed conventional acid dyes and basic dyes. When a vinyl compound capable of providing a high molecular weight compound having a negative charge is used, a basic dye is employed. When a vinyl compound capable of providing a high molecular weight compound having a positive charge is used, an acid dye is employed. In other words, since a basic dye has a positive charge, it selectively dyes high molecular weight compounds having a negative charge, while since an acid dye has a negative charge, it selectively dyes high molecular weight compounds having a positive charge. Thus, a color image can be obtained in accordance with the charge of the high molecular weight compound.

In the case of employing gelatin as a binder in a photographic emulsion, the isoelectric point of the gelatin must be considered for dyeing, since gelatin is an amphoteric electrolyte. In other words, if the pH of the system is lower than the isoelectric point of the gelatin to be used, the gelatin is positively charged, while if the pH is higher than that, the gelatin is negatively charged. Accordingly, when a high molecular weight compound having a negative charge is formed, only the image of the high molecular weight compound can be dyed without dyeing gelatin by dyeing the polymer image with the basic dye at a pH lower than the isoelectric point of the gelatin. Also, the photographic emulsion layer after the formation of images of a high molecular weight compound is first uniformly dyed at a pH higher than the isoelectric point of gelatin and thereafter the layer is washed with a washing solution having a pH lower than the isoelectric point of gelatin, whereby the areas having no images of the high molecular weight compound are washed out to leave the colored image areas of the high molecular weight compound. If it is desired to dye an im age of a high molecular weight compound having a positive charge with an acid dye, the process may be conducted at a pH higher than the isoelectric point of gelatin. Of course, if the pH of the system is too high or too low, the solubility of the dye is lowered, and the electrolytic dissociation of the high molecular Weight compound to be charged may be hindered. Thus, the optimum range of pH depends on the type of the vinyl compound and the dye as well as the kind of binder used, such as gelatin. However, in the case of using a normal gelatin, which has been subjected to line processing and has an isoelectric point at a pH of about 4.9, a suitable pH for the system is 2.5 to 4.5 when a high molecular weight compound having a negative charge is dyed by a basic dye and 5.0 to 8.0 when a high molecular weight compound having a positive charge is dyed with an acid dye.

The examples of the acid dyes used in this invention are, for instance, C.I. Acid Yellow 7 (Color Index 56,- 205), C.I. Acid Yellow 23 (C.I. 19,140), C.I. Acid Red (C.I. 18,050), C.I. Acid Red 52 (C.I. 45,100), C.I. Acid Blue 9 (C.I. 42,090), C.I. Acid Blue 62 (C.I. 62; 045), and C.I. Acid Violet 7 (C.I. 18,055). Also the examples of the basic dyes used in this invention are C.I. Basic Yellow 1 (C.I. 49,005), C.I Basic Yellow 2 (C.I. C.I. Basic Red 1 (C.I. 45,160), C.I. Basic Red 2 (C.I. 50,240), C.I. Basic Blue 25 (C.I. 52,025), C.I. Basic Vioiet 3 (C.I. 42,555), and C.I. Basic Violet (C.I. 45,170).

The numbers of the dyes given above are taken from the Color Index (2nd edition).

In carrying out the process of this invention, it is necessary to conduct the step of irradiation by electromagnetic rays or particle rays, the step of reduction and polymerization, and then the step of dyeing.

Polymer images can be formed by washing away only the unpolymerized portion of the vinyl monomer after exposure, reduction, and polymerization, because the polymer is less soluble than the monomer and can scarcely diffuse through the high polymer such as gelatin which is used as a binder for the silver halide photographic emulsion. By utilizing monomers having at least two vinyl groups in combination, insolubility and non-dissolubility of polymer obtained can be increased. Dye images corresponding to the polymer images are obtained by dyeing, as aforementioned, after polymerization. The images which are made by this procedure can be utilized as clear dye images by fixing the silver halide to remove it, and then dissolving out the silver image by applying an oxidizing agent and a solvent for silver salts.

In the case where a reducing agent having a high efficiency of initiating polymerization is used in the present invention, it is unnecessary to remove silver images by 14 the oxidation, since enough polymerization reaction has already occurred in such a condition that only a very small amount of reduced silver is produced. In other words, a dense silver image is not produced.

Further, the dye images thus produced can be transferred onto other supports. In carrying out such a transfer, a support to receive dye images must be brought into intimate contact with a layer containing dye image produced as above mentioned, which is wetted with a solvent for the dye such as methanol, water, or an aqueous solution of acid, base or salt. The supports onto which the dye image is to be transferred may be of ordinary paper, or paper or film coated with a hydrophilic polymer of gelatin can be used. When the dye image is to be transferred to a support which is coated by gelatin, it is preferable to treat it with a mordant such as aluminum salt beforehand, in the same way as the usual dye transfer process. When an image composed of the ionizable polymer is made, it is possible to make a number of copies by dyeing and transferring as above mentioned, since several copies can be made with one dyeing and the polymer image can be dyed repeatedly.

The invention is illustrated, but not limited, by the following examples:

EXAMPLE 1 A fine grain gelatin silver chlorobromide photographic emulsion which contained silver chlorobromide, corresponding to about 42 g. of elementary silver and containing chlorine and bromine in molar ratio of 7:3, and about 60 g. of gelatin per liter was divided into two portions and was exposed to fluorescent lamps. For the purpose of exposure, 200 cc. of the liquid emulsion at 35 C. was spread in a vat of 20 cm. x 25 cm. and then exposed to light of about 300 luxes for 5 minutes with continuous agitation. Thereafter, 2 ml. each of the exposed emulsion and unexposed emulsion was charged into a test tube of about 1.6 cm. in diameter and after adding 6 ml. of water, 4.0 g. of acrylamide and then 10- mole of p-hydroxyphenyl acetic acid, No. 35 in the list, were added to the mixture. While agitating the mixture, the temperature of the sample was adjusted to 48 C. and the test tube containing the sample was set in a heat insulating material. Polystyrene foam of about 2 cm. thickness was used as the heat insulating material and the samples together with the heat insulating material were immersed in a water bath, the temperature of which was maintained at 50 C. To each of the samples 2.0 cc. of 1 N aqueous sodium hydroxide solution was added immediately, and then the changes in the temperature of the samples were recorded with a thermister temperature recorder. In the exposed emulsion, acrylamide was polymerized to raise the temperature of the system by the heat of polymerization. The temperature of the system reached 96 C. at about 82 minutes after the start of reaction, and the content of the test tube became rubbery due to the polyacrylamide formed, and was. not dissolved in a large quantity of methanol.

'On the other hand, in the system of the unexposed emulsion, the temperature increase was scarcely observed, the content in the test tube could be easily poured out. When the content therein was poured in a large quantity of methanol, only a small amount of precipitate, which was considered to be the gelatin originally present in the emulsion, was formed. In this case, it was found that in the system of the exposed emulsion, the color of the system was changed to brown due to the reduction of silver halide.

Under the conditions similar to above, the increase in the amount of acrylamide, from 4 g. to 6 g., further to 8 g., caused a shortening of the reaction time. For example, when 6 or 8 g. of acrylamide was used, the temperature reached to 100 C. after 27 minutes and 21 minutes, respectively, in the case of exposed emulsion, while the temperature of the unexposed emulsion reached only to 50 C. and 53 C., respectively, at the same time.

Also, the same procedure was repeated by using 10 mole of the reducing agent, and, in the system where the exposed emulsion was employed, the temperature reached 100 C. after 125 minutes, while in the system where the unexposed emulsion was used, the temperature reached 16 emulsion, 4 g. of acrylamide, 2 ml. of water, 1 ml. of a 1 mole/liter solution of the phenol shown in Table 2, and an aqueous l N sodium hydroxide solution in an amount shown in the same table. The results are shown in the following table.

50 after minutes. TABLE 2 Thus, that polymerization has occurred is obvious from R B C E the generation of the heat of polymerization, and the educmg agent (A) (D) change in fluidity of the whole system. The heat might be 20 Tyramine- 3.0 33 100 51 50 generated by reduction of silver halide other than polym- 18 gf fi figfigggf 20 10 97 56 55 erization reaction, but it was too little to be detected as N E t {1 N N OHu d F on OTM- 311101111 0 8. S6 err 11116 retempf'irature change m the apparatus emplfwed herem' quired to reach the highest temperature (min); (0) Temperature of the F01 mstance, when hydroquinone Was used instead Of pexposed emulsion at the time 0.); (D) Temperature of the unexposed hydro-xyphenyl acetic acid, the silver halide was reduced 8111111510 C')atthet1me(B)'and(E)Bathtempemtur to form black silver but no generation of heat was ob- I served. That the heat generation was due to the polym- A5 Clear ffOIh Table 1n the ease of h exposed emul" erization reaction can be seen by the fact that the heat the leaetlen' Occurred fastelf than 111 the F'f of the generated varied depending on the amount of the reduche p elhulsloh- The eXperlmehtal eehdltlehs were ing agent used also suggests that the polymerization reslmllaf t0 those of EXample action occurred. EXAMPLE 4 EXAMPLE 2 T d E I d Although Examples 1 through were carried out using using th r a lieri dlz gh y v n T able l iii st eat 'l Zi 1352:4 1 Water 1 1 3 Vinyll onipounds, 1ssilrgbhtly scl luble tetiraethylene co imet acr ate cou e o erize in an pheuylacetlc acid and varying the amount of sodium hyemuliign' y p ym g gfi 1 33 2 'g igj g lgi ig g i g j A tetraethylene glycol dimethacrylate emulsion was prethe amouni of 1 N a ueou sodiurn h dro id solution pared by mixing 20 ml: of tetiaethylene glycol and 20 in column 5 the p g time unfilythextefnperature of a 4% aqueous gelatin solutlon and after the addition of 4.0 g. of sodium dodecylbenzene sulfonate the mixture of the tm usm th ex os d emul 'on r c t e maximuii i iii columr i 7 :he riiax imum te riiperaii ir e tileli was emulslfieddm gmulslfier'hlz of fi emu}- sion was mixe wit 2 m .o t e same p otograp ic emu 25 gg g g s g s igl igg Ofdthe e the sion as in Example 1, and after adding 10 mole of pose emulsion 15 tyramine 2 0 ml of an aqueous 1 N sodium hydroxide ployed, in column 8. It will be understood from these results that in all cases, the reaction was inducted preferg mole of g proentially in the case of the exposed emulsion. Dre 0 Xamp e repeate at 0 i t 6 System using the exposed emulsion, the heat of reaction reached EXAMPLE 3 46.5" C. after 70 minutes, while in the system using the Polymerization was conducted using an emulsion com unexp osed emulsion, the reaction temperature reached only taining, as protective colloid, polyvinyl alcohol and polyto 42 a tthatt1me' vinyl pyrrolidone instead f gelatin Thus, it is shown that even a water lnsoluble or scarcely Using a fine grain silver chlorobromide emulsion which Soluble e be pe y $e1eet 1Ve1Y 111 the contained silver chlorobromide, corresponding to about Presence of sllvef hahde f has been shhleeted t0 the 20 g. of elementary silver and containing chlorine and exposure to eleetl'omaghetle Waves of Partlele y bromine in molar ratio of 7:3, about 30 g. of polyvinyl- EXAMPLE 5 pyrrolidone and about 100 g. of polyvinyl alcohol per liter of the emulsion, the emulsion which had been ex- A P g p .llghhsehsltlve h havlhgh layer f a posed to li h i h Same way as Example 1 f ten photographic gelatino silver chloroiodobromrde emulsion me was compared ith th l io unexposed Th was lmage exposed and the layer was treated by a solution experiment was conducted by adding to 10 ml. of the containing p-benzylphenol, No. 7 in the list, and the image TABLE 1 Chemical Bath Amount F Time B. number Reducing agent Amount temp. of alkali temp. (min) temp.

15 2,3,5,6tetra methylphenol 75 35 4.0 40 29 38.1 13 3,4,5t1imethy p 136 35 2.0 72.8 46 35 14..--

2,3,5-tr1'methylnhennl 126 35 4.0 47.8 90 41 g iicetoacetyl-p-cresol 1155 $03 2% 2.3

yrosine 8 6 30 3,5-diiodotyrosine 433 45 1.0 100 s7 52 24 2,6-b1's-(hydroxymethyl)-p-cresol 168 48 2.0 56 27 61.5 18 Dimethylaminornethylphenol (o.p. mixture) 151 48 2. 0 98.1 30 48. 1 19.. Hordenine sulfate 465 48 2.0 100 18 48 10 5 149 48 2.0 75 57 5s a a 2; as a 91 5-hydroxyhydrindene 134 48 210 70 9 a a a a a -B.I11l!10n FY10 11.- 3-methyl-4-isopropylphenol 160 48 2.0 54 48 49 27.. 2-chlor0-4,B-dimethylphenol- 155. 5 50 2.0 76 27 56 g hY% y p g 5-8 5% PYP To 26..-: 2-bromo-4-t-butylphenol 220 3.0 72 6 36 3-i0d0salieylic acid 264 57 4. 0 79 160 65 p-Iodonh Mm] 220 57 3. 0 s9 98 72 Iran at 27 i8 22 a $2 6.- -00 y p ene 6-chloro-m-cres0l 142 57 5.0 100 112 80 2-dimethylamin0rnethyl-3,ti-xylenol 179 57 1. 0 8O 60 66 4,6-dichloro-o-cres0l 176 57 1.0 67 20 6 142 57 1.0 88 115 so 28 4-chloro-m-cresol 17 consisting of polyacrylic acid thus formed was dyed by a basic dye.

The film had been prepared by applying a subbing coat to both sides of a polyethylene terephthalate film, applying an antihalation layer to one of the surfaces of the so under-coated film, and applying to the other surface a silver halide photographic emulsion. The photographic emulsion was prepared by adding a suitable amount of merocyanine dyes with a sensitization maximum of about 550 mm. for the sake of optical sensitization, and 1.5 g. of mucochloric acid as a hardening agent and adding further suitable stabilizing and wetting agents to a gelatino silver chloroiodobromide emulsion containing, per mole of silver, about 0.7 mole of chlorine, about 0.3 mole of bromine, about 0.001 mole of iodine and about 100 g. of lime processed gelatin. The resulting coated film contained 50 mg. of silver per 100 cm. A gelatin protective layer of about 0. 8p. thickness was further applied on said emulsion layer. The resulting product is suitable for making line and half-tone images .for the graphic arts.

After placing negative bearing line images on the emulsion layer of the photographic film thus prepared, the emulsion layer was exposed for 2 seconds to light of about 100 luxes and thereafter immersed in a solution having the following composition under a red stable light.

Sodium methacrylate 7.5 g.

p-Benzylphenol 0.83 g.

Potassium methabisulfite 0.3 g.

2 N sodium hydroxide The amount necesary to adjust the pH to 11.5.

Water 12 ml.

When the photographic film thus processed was allowed to stand for 30 minutes at 30 C., a faint brown image was formed at the exposed portions. After washing the sample for 30 seconds with an aqueous 1.5% acetic acid solution, the sample was fixed with the following fixing solution:

G. Sodium thiosulfate (anhydrous) 150 Potassium methabisulfite 15 Water, 1 liter.

After fixing sufliciently, and rinsing with Water, the sample was immersed in a 0.1% aqueous solution of a red basic dye (Rhodamine 6 G.C.P., C.I. Basic Red I) for minutes at room temperature. Thereafter, when the sample was washed with an aqueous 5% acetic acid solution for 5 minutes, the dye at the areas other than the brown image area was washed out, while the image portions remained colored red. Since the brown image was a silver image, the silver image could be removed by Farmers reducer. By removing the silver image, a clear red image was obtained. When the order of dyeing and removal of silver image was changed, that is the silver image was first removed to provide a colorless and transparent image and thereafter the image was dyed, a clear red image was also obtained.

The dye image thus prepared could be transferred to paper. Thus, the surface of a usual writing paper was lightly rubbed by a sponge containing methanol to wet the surface with methanol, the color image prepared above was brought into close contact with the wet surface of the paper, and both members were separated after about 30 seconds; the red image was thereby transferred onto the paper.

By using Crystal Violet (0.1. Basic Violet 3) as an 0.1 aqueous solution, the dye image was prepared by the same procedure, and the blue-violet image could be transferred to a paper.

Also, by using a 0.1% aqueous solution of Auramine 0100, (0.1. Basic Yellow 2), a yellow image was obtained. Moreover, by using an 0.1% aqueous solution of Basic Blue G0. (01. Basic Blue 25), a blue image was obtained.

In transferring the dye image, it was unnecessary to remove the silver image or to remove silver halide, and hence by immersing the film in a stopping bath after conducting development and polymerization, washing with water, and then immediately dyeing and transferring the image, a good transferred image could be obtained.

EXAMPLE 6 The photographic light-sensitive film as in Example 5 was exposed as in the same example, and then immersed in the solution having the following composition:

Sodium acrylate 7.5 g.

3,4,5-trimethylphenol 0.611 g.

1 N-sodium hydroxide Amount necessary to adjust the pH to 11.5.

Water 14.5 ml.

EXAMPLE. 7

The same experiment as in Example 6 was repeated by using orthoxylenol '(No. 8 in the list) instead of 3,4,5- trimethylphenol. The composition of the solution in which the photographic light-sensitive film was immersed is as follows:

Sodium acrylate, g 7. 5 7. 5 Orthoxylenol, g 0. 55 0. 55 1 N aq. sodium hydroxide solutlon, ml 0. 55 2. 0 Water, ml 14. 5 13. 0

For detecting the effect of pH, two kinds of solutions, A and B, were prepared as above. The pH of solution A was 10.0 and that of solution B was 11.7. When solution A was employed, the film immersed was allowed to stand for minutes at 30 C., while when solution B was employed, the film was allowed to stand for 20 minutes at 30 C. By thereafter subjecting the film to the post-treatment as in Example 5, it was confirmed that a strong layer of a polymer was formed at the exposed areas.

As will be understood from the periods of time in solutions A and B, shown above, the rate of reaction was higher as the pH of solution was higher. When 3,5-trimethylphenol (No. 14 in the list), 3-butyl-4-isopropylphenol (No. 3), S-hydroxyhydrindene (No. 9), p-benzylphenol (No. 7), or 5,6,7,S-tetrahydro-B-naphthol (No. 10) was employed as the reducing agent instead of nrthoxylenol in the aforesaid procedure and the pH of solution was kept at 10.0 or 12.5, a strong layer was formed in a shorter period of time and at a higher pH in every case.

EXAMPLE 8 The photographic light-sensitive film, as in Example 5, was exposed as in the same example and was processed in a solution having the following composition.

Sodium methacrylate 7.5 g. Reducing agent Shown in Table 3. Water 13 m1. Potassium methabisulfite 0.3 g. 2 N aq. sodium hydroxide The amount necessary to solution. adjust the pH to the value shown in the table.

After processing at 30 C. for the period of time shown in Table 3 the sample was fixed, rinsed with water, and dyed with 0.1% Rhodamine 6 G.C.P. as in Example 5.

19 The transmission density of the exposed and unexposed portions to the green light was measured before and after dyeing. The kind of reducing agents, the amount thereof, the pH during processing, the processing time, the optical density before dyeing and the optical density after dyeing are shown in Table 3.

It will be understood that in every case, the density increase by dyeing the exposed portion was higher than that of the unexposed portion, and hence the exposed portion was dyed selectively. This was also clear from the tion of a red acid dye, Solar Rhodamine B extra (C.I. Acid Red 52) was employed. Thus, the film having a polymer image was immersed in the dye solution for minutes, to dye the whole area of the layer, and thereafter immersed for 3 minutes in a Kolthoffs buffer solution, having a pH of 5.0, followed by rinsing to provide the sample in which only the image area was dyed red. The dye image could be transferred to a writing paper wetted by ethanol. The image could be transferred also to the wet receiving paper described above.

0 fact that by removing the silver image 1n each sample Furthermore, when the layer having a polymer image with Farmers reducer, a clear red image was obtained. was dyed by using a yellow dye, Solar Pure Yellow 8 G Moreover, in a case where the sample had a silver image (C.I. Acid Yellow 7), and washed with a buffer solution of low density, a clear sharp red image was obtained withhaving a pH of 5.0, a yellow image was obtained and by out removing the silver image. The dye images of the contacting the dye image under pressure with a receiving sample could be also transferred to writlng papers using paper wetted with water. The yellow image also could be methanol as in Example 6. transferred to the paper.

EXAMPLE 9 EXAMPLE 10 The photographic light-sensitive film of Example 5 was exposed as in the same example and then processed in the By using a photographic light-sensitive film having a solution having the following composition to conduct silver iodobromide emulsion, the polymerization of sodevelopment and polymerization. dium methacrylate was conducted. In this example, orth- 1-vinyl-2,3-dimethylimidazo- 7.5 g. 3 055 rls g 3f ti lium p-toluene sulfonate. 16 1g Y a W 10 i usua p oys 1n preparation of line lmages or continuous tone images Orthoxylenol 549 mg. Potassium methasulfite 03 with steep gradation 1n photoengravmg processes, was pre- 2 N aq. sodium hydroxide The amount necessary to pared y solution. maintain a pH of 11.5. PP Y a subbing layer 10 both 81065 of a cellu- Water 7.5 ml. lose triacetate base;

TABLE 3 Density of non- Density of exposed portion exposed portion atatch j al Amount Time Before After Before After number Reducing agent used pH (min.) dyeing dyeing dyeing dyeing 18 Dimethylphenol (0.1). mixture) 0. 68 9-0 80 0- 08 0- 9 0- 09 0.44 s Orthoxylenol 0.00 11. 5 0. 30 0.76 0.56 1. 54 Hordenine sulfate"--. 0. 76 10. 5 30 0. 10 0. 28 0. 28 0. 42 Iodosalicylic acid 1.19 9.0 60 0.07 0.39 0.07 0.76 0.83 11.5 30 0.15 0. 49 0.25 2.00 1. 55 9.0 so 009 0.45 0.08 0.76 2-acetyl-1-naphth0l 0. 84 9.0 80 0.07 0.26 0.08 0.35 1 p-Crpsnl O. 49 11. 5 60 0. 21 0. 34 O. 26 1. 59 38 .0mm 0.49 11.5 40 0.24 0. a9 0. 34 0.84 39 2-hydroxymethylphenol 0. 56 11- 60 0.07 0.68 0.08 1.99 41. 2-(N,N-diethylaminomethyD-l-naphthol- 1.02 11.5 60 0.09 0.38 0.17 2.45 42- Orthohydroxypheuylacetic acid 0. 68 11. 5 00 0. 07 0. 34 0. 08 1. 60 Water, ml. 7.5

The 1 vinyl-2,3-dimethylimidazolium-p-toluene sulfo- (2) Applying ran anti-halation layer to one surface of the nate used in this example had been prepared by reacting subbed base; 1-vinyl-2-methylimidazole and methyl p-tolueue sulfonate (3) Applying, to the other surface of the base, a fine at normal temperature and recrystallizing with ethanol grain gelatin-silver halide emulsion containing about 0.012 and ether and had a melting point of 142.5 C. mole of iodine, about 0.988 mole of bromine, 204 g. of When the film was processed for 60 minutes at 30 C., gelatin per mole of silver, sensitized with a rhodanate an image of a polymer of a quaternary salt was formed complex of monovalent gold, and added with about 0.7 g. together with a faint brown silver image. Thus, after fixper 100 g. of gelatin, of mucochloric acid and a suitable ing and rinsing in the manner similar to Example 5, the surface active agent, in an amount to provide a coating image of polymer was dyed by using a 0.1% aqueous layer containing mg. of silver per 100 sq. cm.; and solution of a blue acid dye, Suminol Leveling Sky Blue R (4) Applying thereover a protective layer of gelatin of extra come. (01. Acid Blue 62) and then washed with a about 0.8 micron thickness. 1% aqueous solution of sodium bicarbonate for 5 minutes 60 A negative line image was placed in contact to the emulto provide a blue image. By removing the silver image sion layer of the light-sensitive film prepared above and from the thus obtained image, as in Example 5, a clear the layer was exposed for 10 seconds to light of about 1400 blue image could be obtained. Furthermore, by contacting luxes and then processed in the solution having the folthe blue image under pressure with a writing paper wetted lowing composition under a red safe-light; by methanol, the image could be transferred to the paper. 65

Moreover, when a receiving paper, prepared by applydium methacrylate 7.5 g. ing a gelatin layer to a baryta-coated paper in a thickness Orthoxylenol 0.54 g. of 10 microns, immersing the paper in an aqueous solu- Potassium metabisulfite 0.3 g. tion of alum, and drying, was wetted by water closely con- Water 7.5 ml, tacted to the aforesaid dye image and allowed to stand 2 N aq. sodium hydroxide The amount necessary to adjust for 1 minute, the dye image was transferred to the receiving paper and after separation a clear blue image having high density was obtained.

Instead of employing the aqueous solution of the Suminol Leveling Sky Blue R extra conc., a 1% aqueous solusolution. the pH to 11.5.

When the film was processed in the solution for 50 minutes at 30 C., a faint brown image was obtained. After fixing and rinsing as in Example 5, the layer was dyed with Rhodamine 6 GCP and a dye image having a high density was obtained only at the exposed portions.

EXAMPLE 11 The same photographic light-sensitive film as used in Example was irradiated by X-rays and thereafter processed in the same way as in Example 5.

The X-ray exposure was conducted at 30 kv. and ma., using a cobalt X-ray tube made by Phylips Co. In this case, a part of the sample had been covered by a razor blade of 0.2 mm. in thickness and the sample had been place in front of a window of the X-ray tube at the distance of 1 cm.

The exposed layer was processed for 18 minutes at 30 C., as in Example 5, fixed, rinsed, and dyed by Rhodamine 6 GOP, whereby a silver image was formed at only the portions directly irradiated by X-rays and these portions were selectively dyed.

Thus, as shown in the example, it will be understood that the process of this invention can also be applied to a silver halide emulsion layer exposed to a high energy ray as well as visible rays.

What is claimed is:

1. A process for forming polymer images by develop ment polymerizing at least one addition-polymerizable vinyl monomer without the formation of a dense silver image, said process comprising:

imagewise exposing areas of a photographic silver halide emulsion layer, said areas containing silver halide particles and said areas being the areas in which said polymer images are to be formed, thereby forming a latent silver image in said images; and

thereafter treating said areas having said latent silver image, in the presence of at least one addition-polymerizable vinyl compound and water, with at least one phenol compound, whereby the polymerization of said vinyl compound in said areas is initiated by the oxidation product of said silver halide particles and said phenol compound and wherein the silver particles forming said latent silver image are not totally reduced to form a dense silver image, and wherein said phenol compound is represented by the following formula:

wherein each of R R R R and R is selected from the group (a), (b), and (c), as follows:

(a) R represents a member selected from the group consisting of methyl, hydroxymethyl, dialkylaminomethyl, bnomomethyl, carboxymethyl, carboxyl, and acyl groups; R and R each represent a member selected from the group consisting of hydrogen and alkyl groups; R represents a member selected from the group consisting of hydrogen, halogen, and alkyl groups; and R represents a member selected from the group consisting of hydrogen, halogen, alkyl and hydroxymethyl group; said R and R may form a naphthalene ring;

(b) R and R each represent a member selected from the group consisting of hydrogen and halogen atom; R and R each represents a member selected from the group consisting of hydrogen and alkyl groups; and R represents a member selected from the group consisting of halogen, alkyl, aralkyl and substituted alkyl groups; said R and R may form an alkylene ring of l to 6 carbon atoms; and

(c) R R R and R each represents hydrogen and R represents a tertiary alkyl group.

2. The process as claimed in claim 1 wherein said latent image is formed by exposing imagewise the photographic silver halide emulsion layer formed on a support to visible rays or high energy rays and said polymerization is conducted by immersing said layer, after said imagewise exposure in an aqueous alkaline solution containing said monomer and said phenol.

3. The process as claimed in claim 1 wherein the polymerization is conducted in the presence of sulfite ions.

4. The process as claimed in claim 3 wherein said latent image is formed by exposing imagewise the photographic silver halide emulsion layer formed on a support to visible rays or high energy rays and said polymerization is conducted by immersing said layer after said imagewise exposure in an aqueous alkaline solution containing said monomer together with said phenol and said sulfite ions.

5. The process as claimed in claim 1 wherein said addition polymerizable vinyl monomer contains a group capable of being charged by electrolytic dissociation or by the addition of a hydrogen cation whereby said monomer is selectively polymerized at the portions of the emulsion layer bearing the latent silver image to form an image of said polymer on said emulsion layer, and dyeing said polymer image selectively with a dye having a charge, when dissociated, opposite to the charge of said polymer.

6. The process as claimed in claim 5 wherein said latent silver image is formed by exposing imagewise the photographic silver halide emulsion layer formed on a support to visible rays or high energy rays and said polymerization is conducted by immersing said layer after said imagewise exposure in an aqueous alkaline solution containing said monomer and said phenol.

7. The process as claimed in claim 6 wherein said aqueous solution further contains sulfiite ions.

8. The process as claimed in claim 5 wherein, subsequent to the formation of the dyed image, said dye image is further transferred to an image receiving element by contacting the image bearing layer with said receiving element.

9. The process as claimed in claim 8 wherein said image receiving element is wetted with a member selected from the group consisting of water and. ethanol at the transfer of the dye image.

10. The process as claimed in claim 1 wherein R and R have from 1 to 4 carbon atoms when alkyl, when R is alkyl there are from 1 to 8 carbon atoms in said alkyl group, and R is methyl when alkyl, and R -R5 are selected from group (a).

11. The process as claimed in claim 1 wherein R and R when alkyl, have from 1 to 4 carbon atoms; R when alkyl, has from 1 to 8 carbon atoms and said R and R when forming an alkylene ring, have from 1 to 6 carbon atoms and -R R are selected from group (b).

12. The process as claimed in claim 1 wherein R is t(er)tiary butyl, and said R R are selected from group 13. The process as in claim 3 wherein said sulfite ions are present in an amount of greater than 0.05 mole per liter of the system.

14. The process as in claim 7 wherein said sulfite ions are present in an amount of greater than 0.05 mole per liter of the system.

15. The process as in claim 1 wherein said vinyl monomer is added to said emulsion layer prior to imagewise exposure in an amount of from g to 30 times, by weight, the amount of high molecular weight material used as the vehicle for said silver halide in said emulsion layer, and wherein said phenol compound is added to said emulsion layer subsequent to imagewise exposure.

16. The process as in claim 15 wherein the amount of said vinyl monomer varies from A to 4 times, by weight, the amount of the high molecular weight material used as the vehicle for said silver halide in said emulsion layer.

17. The process as in claim 1 wherein the amount of silver halide in said silver halide emulsion layer varies from & to 2 times, by weight, the amount of the high molecular weight material used as the vehicle for said silver halide in said emulsion layer.

18. The process as in claim 17 wheerin the amount of silver halide in said emulsion layer varies from to /2 times, by weight, the amount of the high molecular weight material used as the vehicle for said silver halide in said emulsion layer.

19. The process as in claim 1 wherein said phenol compound is added to said emulsion layer prior to imagewise exposure in an amount of from to 20 moles per mole of the silver halide present in said emulsion layer, the vinyl monomer being added subsequent to imagewise exposure.

20. The process as in claim 1 wherein said vinyl monomer and a high molecular weight material used as the vehicle for said silver halide in said emulsion layer are mixed and coated onto a support together with said silver halide to form said phOtographic silver halide emulsion layer prior to imagewise exposure, said film containing from 10 to 20,000 parts per million, by weight, based on the weight of said vinyl monomer of a polymerization inhibitor.

21. The process as in claim 20 wherein said polymerization inhibitor is p-methoxyphenol, hydroquinones, 2,6-ditertiary-butyl-p-cresol or B-naphthol.

22. The process as in claim 2 wherein said aqueous alkaline solution contains from to 5 moles per liter of said phenol compound and said vinyl monomer in an amount as high as possible depending upon the solubility of said vinyl monomer in said aqueous alkaline solution.

23. The process as in claim 22 wherein said phenol compound is present in said aqueous alkaline solution in an amount of from to 1 mole per liter of said aqueous alkaline solution.

24. The process as in claim 1 wherein said vinyl monomer is acrylamide, acrylonitrile, N-hydroxymethylacrylamide, methacrylic acid, acrylic acid, calcium acrylate, methyl methacrylate, sodium acrylate, methacrylamide, methyl acrylate, ethyl acrylate, vinyl pyrrolidone, vinylmethyl ether, vinylbutyl ether, vinylisopropyl ether, vinylisobutyl ether, vinyl butyrate, 2-vinylpyridine, 4-vinylpyridine, Z-methyl-N-vinyl imidazole, potassium vinylbenzene sulfonate, vinyl carbazole, and N,N'-methylenebis-acrylamide, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, divinyl ether or divinyl benzene.

25. The process as in claim 1 wherein said phenol compound is selected from the group consisting of p cresol, 4-t-butylphenol, 3-t-butylphenol, 4-sec-butylphenol, 4-taminophenol, 4-t-octyl-phenol, p-benzylphenol, orthoxylenol, S-hydroxyhydrindene, 5,6,7,8-tetrahydro-fl-naphthol, 3-methyl-4-isopropylphenol, 3-butyl-4-isopropylphenol, 3, 4,5-trimethylphenol, 2,3,5-trimethylphenol, 2,3,5,6-tetramethylphenol, hexestrol, 2-dimethylaminomethylphenol, dimethylaminomethylphenol (QR-mixture), hordenine, tyramine, tyrosine, 2-dimethylaminomethyl-3,6-xylenol, 2,6-dihydroxymethylphenol, 2,6-dihydroxymethyl-p-cresol, p-iodophenol, 2-bromo-4-t-butylphenol, 2-ehl0ro-4,5-dimethylphenol, p-chloro-m-cresol, a-3,5-tribromo-2hydroxytoluene, 3,5-diiodotyrosine, 6-chloro-m-cresol, 4,6- dichloro-O-cresol, O-acetylphenol, 2-acetoacetyl-p-cresol, p-hydroxyphenylacetic acid, 3-iodosalicylic acid, 5-iodosalicylic acid, orthocresol, 2-hydroxymethylphenol, 2- acetyl-l-naphthol, 2 (N,N dimethylaminomethyl) 1- naphthol and orthohydroxyphenylacetic acid.

References Cited UNITED STATES PATENTS 3,585,030 6/1971 Pelz et a1 9629 3,234,021 2/1966 Schwerin et al. 9628 3,041,172 6/1962 Evans 96-115 3,019,104 1/1962 Oster 96--29 2,887,376 5/1959 Tupis 96-35.1 3,038,800 6/1962 Luckey et a1. 9635.1

OTHER REFERENCES Mees, C.E.K.: The Theory of the Photographic Process, 1942, pp. 360-361.

RONALD H. SMITH, Primary Examiner US. Cl. X.R.