US3885968A

US3885968A - Thermally developable light-sensitive material

Info

Publication number: US3885968A
Application number: US474635A
Authority: US
Inventors: Shinpei Ikenoue; Takao Masuda
Original assignee: Fuji Photo Film Co Ltd
Current assignee: Fujifilm Holdings Corp
Priority date: 1974-05-30
Filing date: 1974-05-30
Publication date: 1975-05-27
Anticipated expiration: 1992-05-27

Abstract

A thermally developable light-sensitive material comprising a support having thereon at least one layer containing: (a) silver laurate or silver caprate; (b) a catalytic amount of a lightsensitive silver halide or a compound capable of forming a lightsensitive silver halide by the reaction thereof with the organic silver salt (a); (c) a reducing agent; (d) a binder; and (e) lithium laurate.

Description

United States Patent Ikenoue et al.

[451 May 27, 1975 THERMALLY DEVELOPABLE LIGHT-SENSITIVE MATERIAL Inventors: Shinpei lkenoue; Takao Masuda, both of Asaka, Japan Assignee: Fuji Photo Film Co., Ltd.,

Kanagawa, Japan Filed: May 30, 1974 Appl. No.2 474,635

US. Cl. 96/67; 96/109; 96/114; 96/114.l;96/114.6

Int. Cl. G03c 1/02; G03c 1/34 Field of Search... 96/1 14.1, 114.6, 109, 48 HD, 96/67 References Cited UNITED STATES PATENTS l/1974 Hartman et a1. 96/48 l-lD Primary Examiner-Norman G. Torchin Assistant ExaminerAlfonso T. SuroPico Attorney, Agent, or FirmSughrue, Rothwell, Mion, Zinn & Macpeak [57] ABSTRACT A thermally developable light-sensitive material comprising a support having thereon at least one layer containing: (a) silver laurate or silver caprate; (b) a catalytic amount of a light-sensitive silver halide or a compound capable of forming a light-sensitive silver halide by the reaction thereof with the organic silver salt (a); (c) a reducing agent; ((1) a binder; and (e) lithium laurate.

12 Claims, No Drawings THERMALLY DEVELOPABLE LIGHT-SENSITIVE M ATERIAL BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermally developable light-sensitive material and, more particularly, it is concerned with a thermally developable light-sensitive material having less fogging at the unexposed areas upon being heated (hereinafter referred to as heat fog).

2. Description of the Prior Art Heretofore, the photographic method using silver halide has been the most widely been practiced, since this method provides excellent sensitivity, gradation and similar photographic properties as compared with the electrophotographic method, the diazo-type photographic method, and the like.

However, the silver halide light-sensitive material used in this mehtod must be subjected, after imagewise exposure, to a development processing using a developer and to the several processing steps of stopping, fixing,, washing, stabilizing, etc., in order to prevent the developed image from becoming discolored or faded under normal illumination and also to prevent the nondeveloped area (hereinafter referred to as background") thereof from becoming blackened. Therefore, difficulties in that processing of such a material is time consuming and very laborsome, in that human body is exposed to danger in the handling of the chemicals therefor, and in that the processing rooms and workers hands and clothes are stained exist Therefore, in the photographic method using silver halide, improvements such that the material can be processed in a dry state without solution-processing and such that the processed images can be maintained stable are very desirable.

For this purpose, various attempts have so far been made. One of them is an attempt, as described in Japanese Patent Publication Nos. 26582/69, 12700/70. 22185/70, and 41865/71, and U.S. Pat. Nos. 3,152,904, 3,457,075 and 3,635,719, etc., to use a thermally developable light-sensitive material. In this attempt, a light-sensitive element comprising mainly a silver salt such as the silver salt of a long-chain aliphatic carboxylic acid (e.g., silver behenate, etc.), the silver salt of saccharin, the silver salt of benzotriazole, or the like and a catalytic amount of silver halide is used.

However, in the thermally developable light-sensitive materials which have thus far been suggested which contain a composition comprising a silver salt of fatty acid, a reducing agent and a catalytic amount of silver halide, heat development after imagewise exposure not only blackens the exposed areas but also darkens the unexposed areas as well, thus causing the so-called fog. Of course, if heating is conducted to only such extent that the unexposed areas are not darkened, the exposed areas are not blackened sufficiently to obtain images with a good contrast. Therefore, the darkening of the unexposed areas must be eliminated when heat development is sufficiently conducted.

The incorporation of a mercury ion-providing compound so as to prevent the darkening of unexposed areas, the so-called heat fog, is known, as described in Japanese Patent Publication No. llll3/72. However, as is well-known, mercury compounds are very poisonous and, when a mercury compound containing lightsensitive material is licked, e.g., by babies, there is a great possibility of the mercury compound being ingested into the human body to damage the health of the human being. In addition, since this type of lightsensitive material is developed by heating to C to C, there is the possibility of scattering mercury. Furthermore, in the step of re-using waste lightsensitive materials containing the mercury compounds as reclaimed paper, there is the possibility of the mercury compounds being discharged into rivers. In this case, the mercury compound accumulates in fish and shellfish, leading to damage of the health of human beings consumming the fish and shellfish.

On the other hand, it has heretofore been believed that the silver salts of higher fatty acids such as silver behenate or silver stearate, silver salt of benzotriazole and silver salt of saccharin are suitable as the imageforming compounds. However, in the production of the silver salts of higher fatty acids such as silver behenate or silver stearate in a great quantity, a large quantity of solvent and a large-sized production apparatus is required due to the low solubility of the starting materials; behenic acid or behenic acid salts and stearic acid or stearic acid salts in such solvents as water and methanol, which entails a serious increase in production costs. Also, with the silver salt of benzotriazole and silver salt of saccharin, production cost is increased since the starting materials, benzotriazole and saccharin, are more expensive than fatty acids. In addition, there are no particularly excellent advantages in the photographic properties of these latter materials. Therefore, it is desirable to use a silver salt of fatty acid.

As the silver salt of fatty acids, the silver salts of higher fatty acids such as silver behenate and silver stearate possess the above-described defects. On the other hand, the silver salts of lower chain length fatty acids such as silver acetate tend to be blackened when exposed to room light due to their light sensitivity. Therefore, the white areas in the processed light-sensitive material become darkened to such an extent that the image areas become impossible to discern. Therefore, the silver salts of fatty acids of a medium chain length are expected to be preferable. Thus, it has been found that particularly silver laurate and silver caprate are suitable. The silver salts of fatty acids higher than lauric acid posses the same defects as the above-described silver behenate in no small degree. On the other hand, the silver salts of fatty acids lower than capric acid are not preferred since the starting materials therefor have an offensive odor and posses the defects of silver acetate in no small degree.

Additionally, as is describe in U.S. Pat. No. 3,457,075, silver laurate has also been believed to be poor in stability to light. However, this light stability has now been found to be improved by improving the process for producing silver laurate and the light sensitive composition. The same applies to silver caprate.

SUMMARY OF THE INVENTION An object of the present invention is to provide a thermally developable light-sensitive material using silver laurate or silver caprate.

Another object of the present invention is to provide a thermally developable light-sensitive material which has less fog upon heat development after imagewise exposure of the light-sensitive material.

As a result of extensive investigations, it has been found that lithium laurate is effective for attaining the above-described objects.

That is, the present invention provides a thermally developable light-sensitive material comprising a support having thereon at least one layer containing: (a) silver laurate or silver caprate; (b) a catalytic amount of a light-sensitive silver halide or a compound capable of forming a light-sensitive silver halide by the reaction thereof with the organic silver salt (a); (c) a reducing agent; (d) a binder; and (e) lithium laurate.

DETAILED DESCRIPTION OF THE INVENTION The amount of lithium laurate, componenet (e), used is about 0.0l mol to mols, preferably 0.1 to 2 mols, per 1 mol of silver laurate or silver caprate.

As the lithium laurate, commercially available lith ium laurate of a special grade or that prepared by reacting lithium ion with lauric acid or a lauric acid salt, such as sodium laurate or potassium laurate, can be used. For example, a precipitate of lithium laurate can be obtained by adding an aqueous solution of lithium nitrate to an aqueous solution of sodium laurate. Also, a precipitate of lithium laurate can be obtained by adding an aqueous solution of lithium hydroxide to a metharol solution of lauric acid.

As to the addition of lithium laurate, the lithium laurate can be present during the formation of the silver laurate or silver caprate, or the lithium laurate can be added after the formation of the silver laurate or silver caprate, before or after the formation of the silver hallde. Also, the lithium laurate can be added after components (a) to (b) are all added. Furthermore, it can be present in another layer adjacent the layer containing the silver laurate or silver caprate, although the effects thereof are reduced.

As compounds which can be used as component (b) in the present invention, there are (1) compounds capable of forming a light-sensitive silver halide by the reaction thereof with the above-described organic silver salt (a) and (2) silver halide. Specific examp s ui" 1) are inorganic compounds represented'fiy the general formula;

logen compounds such as triphenylmethyl bromide, 2-bromo-2-methylpropane, 2-bromobutyric acid, 2- bromoethanol, dichlorobenzophenone, iodoform, bromoform, carbon, tetrabromide, an N-haloacetamide, l,3, -dibromo-5 ,5-dimethylthiohydantoin, 1,3- dichloro-S, S-dimethylthiohydantoin, etc. are also included within the scope of the aforesaid compound l The silver halide of compound (2) can be silver cloride, silver bromiodide, silver clorobromoiodide, silver chlorobromide and silver iodide. A suitable particle size can range from about 0.001 p. to 0.5 u, preferably 0.03 p. to 0.2 u. A silver halide containing more than about 50 mol percent bromide is preferred.

Emulsions containing a light-sensitive silver halide can be prepared in any conventional manner known in the field of photography. As such emulsions, there are illustrated, for example, an emulsion prepared by the single jet method, an emulsion prepared by the double jet method (e.g., a Lippmann emulsion), an ammoniacal emulsion, a thiocyanateor thioether-ripened emulsion, the emulsions described in, e.g., US. Pat. Nos. 2,222,264, 3,320,069, 3,271,157, etc., and the like.

The silver halide which can be used in the present invention can be sensitized with chemical sensitizers such as a reducing agent, sulfur, a selenium compound, a gold compound, a platinum compound, a palladium compound, or a combination thereof. Suitable procedures therefor are described in e.g., US. Pat. Nos. 2,623,499, 2,399,083, 3,297,447 and 3,297,446.

The above-described compounds employed as component (b) can be used alone or as a combination of two or more. Component (b) is suitably added in an amount of from 0.01 mol to 0.5 mol, preferably 0.02 mol, per 1 mol of the silver laurate or silver caprate of component (a). If the amount of the component (b) is less than the lower limit of this range, the sensitivity is reduced while if the amount exceeds the upper limit of the range, the non-image areas of the heat-developed material are gradually blackened upon leaving the material under room light, which can spoil the contrast between the image areas and non-image areas.

As the reducing agent which can be used as component (c) in the present invention, reducing agents must be selected which are suitable for reducing the silver salt of component (a) to form images upon heating the light-sensitive material in the presence of exposed silver halide catalyst. Such reducing agents are substituted phenols, naphthols, substituted or unsubstituted bisphenols, hydroquinone monoethers, and the like. A substituted phenol or a substituted bisphenol is preferred.

More specifically, examples of the above-illustrated compounds are given below: 1 l -bis-( 4- hydroxyphenyl) cyclohexane, l,l-bis-(5-chloro-2- hydroxyphenyl)methane, diethylstilbestrol, hexestrol, 2,2-bis-(3,5-dibromo-4-hydroxyphenyl)propane, 2,2- bis-(4-hydroxyphenyl)propane, a-phenyl-o-cresol, hydroquinone monobenzylether, p-nonyl phenol, poctylphenol, p-ethylphenol, p-sec-butylphenol, p-tamylphenol, p-acetylphenol, 2-acetacetyl-4- methylphenol, l-(2-quinolyl)-3-methyl-5-pyrazolone, l-chloro-2,4-dihydroxybenzene, 3 ,5-di-t-butyl-2,6- dihydroxybenzoic acid, 2,4-dihydroxybenzoic acid, re-

sorcin, 2,4-dihydroxyphenylsulfide, 5,7-dihyroxy-4- methylcoumarin, p-methoxyphenol 2-t-butyl-4- methoxyphenol, p-phenylphenol, p-t-butylphen ol B-naphthol, 2,4,5-trimethylphenol bisphenol A, 2,5-dit-butyl-4-methoxyphenol, hydroquinone mono-npropyl ether, hydroquinone mono-n-hexyl ether, 2,3- dimethylphenol, 2,4-di-t-butylphenol, N,N-di(4- hydrozyphenoyl)urea, and the like.

These reducing agents can also be used as a combination of two or more.

Generally speaking, the reducing agent used in the present invention is added in an amount of 0.1 to 5 mols, preferably of 0.5 to 1.5 mols, per 1 mol of the silver laurate or silver caprate of component (a).

In the present invention, components (a), (b), (c) and (e) are preferably dispersed in a binder (d), and are coated on a support. Also, a part or all of these layers can be coated as separate layers. As such a binder, any of those binders which have heretofore been used in this field can be used. Hydrophobic binders are usually preferable, but hydrophilic binders can also be used. Transparent or semi-transparent binders are preferred and illustrative examples are, e.g., natural substances such as gelatin, gelatin derivatives, a mixture thereof with a latex-type vinyl polymer, a cellulose derivative, etc., and synthetic polymer materials.

Specific examples include gelatin, phthaloylated gelatin, polyvinyl butyral, polyacrylamide, cellulose acetate butyrate, cellulose acetate propionate polymethyl methacrylate, polyvinyl pyrrolidone, polystyrene, ethyl cellulose, polyvinyl chloride, rubber chloride, polyisobutylene, butadiene-styrene copolymers, vinyl chloride-vinyl acetate copolymers, vinyl acetate, vinyl chloride-maleic acid copolymers, polyvinyl alcohol, polyvinyl acetate, benzyl cellulose, cellulose diacetate, cellulose triacetate cellulose propionate, cellulose acetate phthalate, and the like. These can be used as a combination of two or more as the case may be. Preferred binders are polyvinylbutyral, polyvinylacetate, ethylcellulose, polymethyl-methacrylate and celluloseacetatebutyrate. The weight ratio of the binder to the silver laurate or silver caprate of component (a) is suitably about 4:1 to about 1:4, preferably 2:1 to 1:2.

As the support which can be used in the invention, wide variety of materials can be used. Representative examples of supports are a cellulose nitrate film, a cellulose ester film, a polyvinyl acetal film, a polystyrene film, a polyethylene terephthalate film, a polycarbonate film, glass, paper, metal, and the like. Where an organic solvent is used in the emulsion layer, a support paper subjected to a processing to impart hydrophilicity, e.g., to a surface-treating with polyvinyl alcohol, is suitable. Also, papers sizing-processed. with saccharides are suitable.

The suitable amount of the above-described binder dispersion to be coated on a support is about 0.2 to 3 g/m (calculated as silver), more preferably, 0.4 to 2 g/m. If the amount coated is less than 0.2 g/m sufficient image density cannot be obtained while if the amount coated is greater than 3 g/m the production cost is increased.

An anti-static layer or an electroconductive layer can be provided on the thermally developable lightsensitive material used for the practice of the invention. Also, an anti-halation substance and an anti-halation dye can be incorporated in the material.

In the thermally developable light-sensitive material used in the practice of the present invention can further be incorporated if desired, a matting agent such as starch, titanium dioxide zinc oxide, silica, etc. Also, flucrescent brightening agents such as the stilbenes, triazines, oxazoles, coumarines, etc. can be incorporated in the material.

Some of the optically sensitizing dyes which have heretofore been used for silver halide emulsions can advantageously be used so as to impart increased light sensitivity to the thermally developable light-sensitive material of the present invention. Suitable optical sensitizing dyes are disclosed for example, in U.S. Pat. No. 3,457,075. For example, optical sensitization can be effected by adding a sensitizing dye as an organic solvent solution or a dispersion. Suitable optical sensitizers are, e.g., cyanine dyes, merocyanine dyes, rhodacyanine dyes styryl dyes, Erythrosine, Eosine, tetrachloro tetrabromofluorescein, 2 ',7 dichlorofluorescein or like acidic dyes. The amount of these dyes can range from about 10 mol to about l0 mol per 1 mol of the silver laurate or silver caprate of component (a).

Furthermore various additives such as a toning agent (e.g., phthalazinone, etc.), a stabilizing agent (compound capable of preventing discoloration of images with the lapse of time after image formation (e.g., benzenesulfonic acid, p-toluenesulfonic acid, tetrabromophthalic acid, tetrabromophthalic acid anhydride, etc.) can be incorporated in the thermally developable light-sensitive layer.

Still further, in order to enhance transparency of the thermally developable light-sensitive layer to increase the image density and to improve the storage freshness (i.e., the retention upon storage of the photographic properties of the light-sensitive material immedately after production thereof), a top-coating polymer layer can be provided on the lightsensitive layer. The film thickness of the top-coating polymer layer can suitably range from about 1 p. to 20 t. Suitable polymers are, e.g., polyvinyl chloride, polyvinyl acetate, vinyl chloridevinyl acetate copolymers, polyvinyl butyral, polystyrene, polymethyl methacrylate, polyurethane rubber, xylene resins, benzyl cellulose, ethyl cellulose, cellulose acetate butyrate, cellulose diacetate, cellulose triacetate, polyvinylidene chloride, chlorinated polypropylene, polyvinyl pyrrolidone, cellulose propionate, polyvinyl formal, cellulose acetate phthalate, polycarbonate, cellulose acetate propionate, and the like.

The thermally developable light-sensitive layer and the top-coating layer to be used in the practice of the present invention can be applied to a support using various coating methods including a dip-coating method, an air knife-coating method, a curtain-coating method, and an extrusion coating method using a hopper as described in U.S. Pat. No. 2,681,294. If desired, two or more layers can be applied at the same time.

The above-described thermally developable lightsensitive material can be developed, after being exposed, e.g., for about 10 second to 10 seconds, to radiation from a xenon lamp, a tungsten lamp a mercury lamp or like light source by merely heating the light-sensitive material. Heating temperatures of about to 180 C, more preferably, C to C, are suitable for such development. Higher or lower temperatures can be selected within the above-described range by prolonging or shortening the heating time appropriately. The developing time is usually from 1 second to about 60 seconds.

Various means for heat-developing the light-sensitive material of the present invention can be used. For example, the light-sensitive material can be contacted with a simple heating plate or the like or with a heated drum, or, in some cases, the material can be passed through a heated space. Also, the material can be heated using high frequency induction heating or using a laser beam.

The thermally developable light-sensitive material in accordance with the present invention has less heat fog in the unexposed areas when development-processed after imagewise exposure.

The present invention will now be illustrated in greater detail by reference to the following non-limiting examples of preferred embodiments of the present invention. Unless otherwise indicated, all parts, percents ratios and the like are by weight.

EXAMPLE 1 A solution prepared by dissolving 8.6 g ofcapric acid in 100 ml of isoamyl acetate was maintained at 5C and while stirring with a stirrer 50 ml of an aqueous solution of a silver ammonium complex salt (cooled to 5C) containing 8.5 g of silver nitrate was added thereto over a 30 second period to react the capric acid with the silver ion. Thus, spindle-shaped silver caprate crystals of a length of about 3 uand a width of about 0.2 uwere obtained The resulting silver salt was washed successively with water and methanol. Thereafter, 3.0 g of polyvinyl butyral and ml of isopropyl alcohol were added to 2.1 g of the silver caprate and dispersed using a ball mill to prepare a polymer dispersion of the silver salt.

To 20 g of this polymer dispersion of the silver salt were added the following components to prepare a thermally developable light-sensitive coating solution. This solution was applied to a paper support in a silver amount of 1.0 g per 1 m of the support to prepare Thermally Developable Light-Sensitive Material (A).

Separately for the purposes of comparison Thermally Developable Light-Sensitive Material (8) not containing lithium laurate and Thermally Developable Light- Sensitive Material (C) containing conventionally known mercuric acetate in place of the lithium laurate of the present invention were prepared in the similar manner.

Ammonium Bromide (2.5% by weight methanol solution) 1 ml Tetrachlorotetrabromofluorescein (sensitizing dye; 0.025% by weight methanol solution) 3 ml Phthalazinone (2.5% by weight methyl cellosolve solution) 1 ml Bisphenol A (70% by weight methyl cellosolve solution) 3 ml Lithium Lauratc l g low.

Light-Sensitive Material Image Density (Maximum Density Area) 1.30 1.45 1.20 Non-image Density (Heatfogged Area) 025 1.00 .18

From the results in above table it can be clearly seen that lithium laurate of the present invention reduces the heat fog and provides sufficient image density, i.e., images with good contrast are obtained.

EXAMPLE 2 The procedures described in Example 1 were repeated except for using 2 g oflithium laurate. When the resulting sample was exposed and heat-developed under the same conditions as described in Example 1, an image of an image density of 1.18 (maximum density area) and a non-image density of 0.17 (heat-fogged area) (reflection density) was obtained.

EXAMPLE 3 11 grams of lauric acid was dissolved in 100 ml of butyl acetate and while maintaining the solution at 10C, 100 ml of a dilute nitric acid aqueous solution (pH at 25C: 2.0) was added thereto under stirring with a stirrer. Then, while continuing the stirring, 50 ml of an aqueous solution (cooled to 0C) of a silver ammonium complex salt containing 8.5 g of silver nitrate was added thereto over a 1 minute period to react the lauric acid with the silver ion. Thus, spindle-shaped silver laurate crystals of a length of about 1 u and a width of 0.05 p. were obtained. The resulting silver salt was washed successively, with water and methanol. Thereafter, 3.0 g of polyvinyl butyral and 20ml of isopropyl alcohol were added to 2.7 g of the silver laurate and dispersed using a ball mill to prepare a polymer dispersion of the silver salt.

To 20 g of this polymer dispersion of the silver salt were added the following components to prepare a thermally developable light-sensitive omposition. The resulting composition was applied to a polyethylene terephthalate film support in a silver amount of 1.7 g per 1 m of the support to prepare Thermally Developable Light-Sensitive Material (A).

Separately, for the purposes of comparison, there Thermally Developable Light-Sensitive Material (B) not containing lithium laurate which is the anti-heat foggant of the present invention was prepared in a similar manner.

Ammonium Bromide (2.5% by weight methanol solution) 1 ml Benzoxazolylidene Rhodanine Sensitizing Dye (0.025 by weight chloroform solution) 1 ml pJhenylphenol by weight methyl cellosolve solution) 3 ml Phthalazinone (25% by weight methyl cellosolve solution) 1 ml Lithium Laurate 2 g Also, Thermally Developable Light-Sensitive Material (C) was prepared in the same manner using mercuric bromide, conventionally known as an anti-heat foggant, in the same molar amount in lieu of the lithium laurate.

On the light-sensitive layer of each of the thus prepared Light-Sensitive Materials (A), (B) and (C) was top-coated a 5 percent acetone solution of cellulose diacetate in a dry thickness of 10 1.1..

Each of these Light-Sensitive Materials (A), (B) and (C) was exposed to a radiation from a tungsten light source (using a step wedge) to impart an exposure of 500,000 lx' sec. Thereafter, the materials were heated at 120C for 20 seconds for development. Thus stepwise images were obtained.

Transmission densities at the image areas and the non-image areas were measured in the same manner as described in Example 1 to obtain the results tabulated below.

Light-Sensitive Materials (A) (B) lmage Density (Maximum Density Area) 1.41 1.61 1.12 Non-image Density (Heatfogged Area) 0.15 0.70 0.13

From the results in the above table, it can be clearly seen that lithium laurate of the present invention reduces heat fog and provides sufficient image density, i.e., images having good contrast were obtained.

EXAMPLE 4 EXAMPLE 5 grams of lauric acid and 2 g of sodium hydroxide were dissolved in 200 ml of water. Then, 100 ml of toluene containing dissolved therein 3 g of lauric acid was added thereto and stirred with a-stirrer to emulsify (800 rpm, 5 minutes). While continuing the stirring, a silver aqueous solution (8.5 g of silver nitrate plus 50 cc of water) was added thereto over a 60 second period to produce silver laurate.

The silver laurate thus precipitated was collected. 30 grams of polyvinyl butyral and 200 ml of isopropyl alcohol were added thereto and dispersed in a ball mill to prepare a silver laurate polymer dispersion. To this silver laurate polymer dispersion were added the following components to prepare a thermally developable light-sensitive composition. This was then coated on a paper support in a silver amount of 0.7 g per 1 m of the support to prepare a thermally developable lightsensitive material.

Ammonium Bromide (2.5% by weight methanol solution) 1 ml Tctrachlorotctrabromofluorescein (sensitizing dye; 0.025% by weight methanol solution) 5 ml p-Phenylphcnol (70% by weight methyl cellosolve solution 3 ml Phthalazinone (2.57: by weight methyl cellosolve solution) 1 ml Lithium Laurate 2 g When the resulting sample was exposed and heatdeveloped under the same conditions as described in Example 3, an image of an image density of 1.43 (at maximum density area) and a non-image density of 0.05 (at heat-fogged area) (reflection density) was obtained.

On the otherhand, a. thermally developable lightsensitive material containing no lithium laurate was prepared for the purposes of comparison. When this material was processed under the same conditions, an image of an imagedensity of 1.45 and an non-image density of 0.15 was obtained. 7

It can be clearly seen that heat fog is prevented with lithium laurate.

' EXAMPLE 6 The same procedures as described in Example 5 were repeated except that neither the sensitizing dye nor the phthalazinone was not used.

The same result as described in Example 5 was obtained except that the sensitivity was less than l/50th that in Example 5, and the color of the image was brown.

The above results demonstrate that lithium laurate has anti-heat fogging effect whether the sensitizing dye and the phthalazinone are present or not.

While the invention has been described in detail and with reference to specific embodiments thereof, it will be apparent to one skilled in the art that various changes and modifications can be made therein without departing from spirit and scope thereof.

What is claimed is:

l. A thermally developable light-sensitive material comprising a support having thereon at least one layer containing: (a) silver laurate or silver caprate; (b) a catalytic amount of a light-sensitive silver halide or a compound capable of forming a light-sensitive silver halide by the reaction thereof with said organic silver salt (a); (c) a reducing agent; (d) a binder; and (e) lithium laurate.

2. The light-sensitive material according to claim 1, wherein said photosensitive silver halide is silver chloride, silver bromoiodide, silver chlorobromoiodide, silver chlorobromide or silver iodide.

3. The light-sensitive material according to claim 1, wherein the compound which reacts with said silver laurate or silver caprate of component (a) to form a photosensitive silver halide is selected from the group consisting of an inorganic compound represented by the formula:

wherein M is a hydrogen atom, an ammonium group or a metal atom, X is a halogen atom, and n is 1 when M is a hydrogen atom or an ammonium group and when M is a metal atom, n is equal to the valence of the metal, and an organic compound.

4. The light-sensitive material according to claim 3, wherein the organic halogen compound is triphenylmethyl chloride, triphenylmethyl bromide, 2-bromo-2- methylpropane, 2-bromo-butyric acid, 2- bromoethanol, dichlorobenzophenone, iodoform, bromoform, carbon tetrabromide, an N-haloacetamide, 1,3-dibromo-5 ,S-dimethylthiohydantoin, or 1,3- dichloro-5,5-dimethyl thiohydantoin 5. The light-sensitive material according to claim 1, wherein the amount of the photosensitive silver halide component (b) ranges from about 0.01 to 0.5 mole per mole of said silver laurate or silver caprate of component (a).

6. The light-sensitive material according to claim 1, where the reducing agent is a substituted phenol, a

naphthol, a substituted naphthol, a substituted or unsubstituted bisphenol or a hydroquinone monoether.

7. The light-sensitive material according to claim 1, where the amount of the reducing agent component (c) ranges from about 0.1 to moles per mole of said silver laurate or silver caprate of component (a).

8. The light-sensitive material according to claim 1, wherein the weight ratio of the binder component (d) to said silver laurate or silver caprate of component (a) ranges from about 4:l to 1:4.

9. The light-sensitive material according to claim 1, wherein said layer additionally contains at least one of or silver caprate of component (a).

l l l

Claims

1. A THERMALLY DEVELOPABLE LIGHT-SENSITIVE MATERIAL COMPRISING A SUPPORT HAVING THEREON AT LEAST ONE LAYER CONTAINING: (A) SILVER LAURATE OR SILVER CAPRATE; (B) A CATALYTIC AMOUNT OF A LIGHT-SENSITIVE SILVER HALIDE OR A COMPOUND CAPABLE OF FROMING A LIGHT-SENSITIVE SILVER HALIDE BY THE REACTION THEREOF WITH SAID ORGANIC SILVER SALT (A); (C) A REDUCING AGENT; (D) A BINDER; AND (E) LITHIUM LAURATE.

3. The light-sensitive material according to claim 1, wherein the compound which reacts with said silver laurate or silver caprate of component (a) to form a photosensitive silver halide is selected from the group consisting of an inorganic compound represented by the formula: MXn wherein M is a hydrogen atom, an ammonium group or a metal atom, X is a halogen atom, and n is 1 when M is a hydrogen atom or an ammonium group and when M is a metal atom, n is equal to the valence of the metal, and an organic compound.

4. The light-sensitive material according to claim 3, wherein the organic halogen compound is triphenylmethyl chloride, triphenylmethyl bromide, 2-bromo-2-methylpropane, 2-bromo-butyric acid, 2-bromoethanol, dichlorobenzophenone, iodoform, bromoform, carbon tetrabromide, an N-haloacetamide, 1,3-dibromo-5,5-dimethylthiohydantoin, or 1,3-dichloro-5,5-dimethyl thiohydantoin

5. The light-sensitive material according to claim 1, wherein the amount of the photosensitive silver halide component (b) ranges from about 0.01 to 0.5 mole per mole of said silver laurate or silver caprate of component (a).

6. The light-sensitive material according to claim 1, where the reducing agent is a substituted phenol, a naphthol, a substituted naphthol, a substituted or unsubstituted bisphenol or a hydroquinone monoether.

7. The light-sensitive material according to claim 1, where the amount of the reducing agent component (c) ranges from about 0.1 to 5 moles per mole of said silver laurate or silver caprate of component (a).

8. The light-sensitive material according to claim 1, wherein the weight ratio of the binder component (d) to said silver laurate or silver caprate of component (a) ranges from about 4:1 to 1:4.

9. The light-sensitive material according to claim 1, wherein said layer additionally contains at least one of an optical sensitizer and a toning agent.

10. The light-sensitive material according to claim 1, wherein said layer additionally contains at least one of a stabilizing agent and a matting agent.

11. The light-sensitive material according to claim 1, including a protective layer over said light-sensitive material.

12. The light-sensitive material according to claim 1, where said lithium laurate is present in an amount of about 0.01 mol to 5 moles per mol of said silver laurate or silver caprate of component (a).