JPH08211547A - Dimension-stable photothermal photographic medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a photothermal photographic element having dimensional stability. SOLUTION: This photographic medium is a thermal developing image forming element developed at a temperature of 100 deg.C-150 deg.C, which consists of a thermal developing image forming composition applied onto a polymer support body. The polymer support body is thermally processed with a low tension at a temperature higher than the glass transition temperature of the polymer, lower than the melting point of the polymer, and not lower than the developing temperature +30 deg.C, whereby the polymer support body is dimensionally stabilized at the developing temperature.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION This invention relates to dimensionally stable photothermographic media.

[0002]

Photothermographic and thermographic imaging media have been widely known for many years. In thermographic media, an image is created by imagewise exposing a thermographic element to heat. In photothermographic media, exposure to actinic radiation forms a latent image. The latent image is developed by subsequently heating the photothermographic element.

These heat developable, photothermographic elements comprise a support having one or more light sensitive, imageable photothermographic layers. The silver halide photothermographic layer usually comprises a photosensitive silver halide, a non-photosensitive reducing silver source, a reducing agent for silver ions, and a binder. By exposing the photosensitive silver halide to light, small clusters of silver atoms (Ag °) are created. The imagewise distribution of these clusters is known in the art as a latent image. This latent image is generally not visualized by conventional means and the photosensitive emulsion must be further processed to produce a visible image. The visible image is created by the reduction of silver ions in catalytic proximity to the clusters of silver atoms, i.e. the silver halide grains bearing the latent image. This reduction occurs by heating the photothermographic element,
A black and white image is created.

Color images can be formed by adding leuco dyes in emulsions. Leuco dye is
It is a reduced form of colored dye. Upon imaging, the leuco dye is oxidized and a colored dye and reduced silver image are simultaneously formed in the exposed areas. In this way, dye-enhanced silver images can be produced. This is the case, for example, in U.S. Pat.
1,286, 4,187,108, 4,426,441, 4,374,921
, And No. 4,460,681.

Unfortunately, high temperature heat treatments change the dimensions of photothermographic elements. These dimensional changes have prevented the use of photothermographic media in many graphic arts applications where precise lines, dots, and images are desired. For example, the developed black and white photothermographic element may be used as a mask in the direct preparation of color separation printing plates or in the preparation of color separation contact negatives or positives. Any dimensional change in the photothermographic element can result in an inaccurate color display.

Various techniques have been used to avoid dimensional changes in thermally developed image elements. For example, during the next heat treatment, the polymer film is heat relaxed at low tension for up to 90 seconds at a temperature within ± 25 ° C of the temperature at which the imaging element is then processed,
Distortion is disclosed to be less than 0.5% in length and less than 0.3% in width. (Method for Preparing Dimensiona
lly Stable Polymeric Film), Research Disclosure 19809, October 1980)

However, US Pat. No. 4,308,342 shows that a dimensional change of greater than ± 0.03% in length or width interferes with accurate color display of the non-silver thermally developed image element. Also, U.S. Pat.
308,342 shows that attempts to use thermal relaxation techniques on polymer supports have not been successful in achieving the desired dimensional stability. Thus, U.S. Pat. No. 4,308,342 provided a non-silver imaging element having a low strain rate. The low strain rate is achieved only by coating the photosensitive material on a support having a low thermal strain rate, followed by preheating the fully coated and dried imaging element before exposure to actinic radiation. It is taught that this can be done.

[0008]

The present invention is a polymer film that can be used as a support in a photothermographic element, wherein the photothermographic element has less than 0.03% heat when treated at a temperature of 110 ° C to 150 ° C. We have found a way to treat polymer films that have strain, which includes shrinkage and expansion. The method avoids preheating prior to exposure and development, thereby avoiding possible element destabilization due to the preheating step.

Thus, in accordance with one aspect of the present invention, the invention comprises a heat-developable imaging composition developed at a temperature of 100 to 150 ° C. and coated on a polymeric support. Developable imaging element. By heat treating the polymer support at a temperature not less than the development temperature + 35 ° C, the polymer support exhibited dimensional stability at the development temperature.

According to another aspect, the present invention is a photothermographic element comprising a dimensionally stable support and a silver halide photothermographic layer, the element being developed at temperatures in the range 100 to 150 ° C. An element having a thermal strain of less than 0.03%.

[0011]

The present invention provides a strain of less than 0.03% in both the machine and transverse directions when the imaged element is developed at a temperature of 100 to 150 ° C, preferably less than 0.025%. A heat developable imaging element that is subject to low strain, and more preferably less than 0.02% strain, comprising a heat developable imaging composition coated on a polymeric support. . The machine direction is the direction in which the support layer film is pulled during manufacturing. The lateral direction is the direction perpendicular to the machine direction in the plane of the support layer. Such a well-balanced and low degree of distortion is important for obtaining an imaging photothermographic element which does not add distortion in the reproduced image.

The polymer support or support layer is 0.07-0.
It has a thickness of 2 mm, preferably 0.1 to 0.15 mm. Although a variety of polymeric materials may be used as the support layer, semi-crystalline polymers are especially desirable. This is because these polymer materials are easily stabilized by thermal calcination. Examples of semi-crystalline polymers include polyethylene naphthalate (P
EN), polyethylene terephthalate (PET), polyether ketone, polytetrafluoroethylene, polyamides, syndiotactic polystyrene, and polyphenylene sulfide.

The desirability of such semi-crystalline polymers has been found by the finding that the dimensional stability of these polymeric support layers can be controlled through a special calcination process. This baking treatment consists of heating the polymer support layers to a temperature above their glass transition temperature and below their melting point. If this calcination occurs at low tension, then some thermal strain will occur when the support layer is subsequently exposed to temperatures below the calcination temperature. Low tension means about 200 psi (1.4 × 10 ⁶ N /
m ² ), preferably about 150 psi (1.04 × 10 ⁶ N /
m ² ), and more preferably less than about 100 pounds per square inch (6.9 × 10 ⁵ N / m ² ). High tension firing causes high strain. Various baking methods may be used, including vented oven baking, hot can baking, film baking rolls, or a combination of these methods.

The time required for firing depends on the firing method used,
It depends on the polymer material of the film and the thickness of the film. Regarding the method of firing, thermal transfer by conduction, such as that which occurs in hot can firing, is more effective than by convection, which occurs in vented oven firing. Therefore,
The firing time for the vented oven bake will be longer than the time required for the hot can bake. For example, 7 mils (0.1
180mm PET film in a forced air oven
For firing at 0 ° C, a firing time as short as 60 seconds has been found to be sufficient to impart dimensional stability to the film. However, in general any firing methods listed here, the baking time, the film firing temperatures increase the time required for (hereinafter, "t _h" abbreviated) often longer than, preferably t _h +5 sec, more preferably t _h +10 seconds, and most preferably t _h +15 seconds.

In order to achieve a suitable degree of thermal strain, the polymeric support layer should be kept above the development temperature of the imaging element.
It is better to fire at a temperature of 30 ° C or higher, preferably 35 ° C or higher, and more preferably 40 ° C or higher. This firing is done before applying additional layers onto the support layer. A preferred heat developable imaging element is a silver halide photothermographic imaging element at 100 to 150 ° C, preferably
It is developed at 110 to 135 ° C. Therefore, according to this preferred embodiment, the support layer film should be baked at 130 ° C. or higher, preferably 165 ° C. or higher, and more preferably 180 ° C. or higher.

A preferred silver halide photothermographic imaging element comprises a photothermographic silver halide imaging composition coated on a fired support layer. The silver halide imaging composition comprises a photosensitive silver halide, a non-photosensitive reducible silver source material, a reducing agent and a binder.

Photosensitive silver halide The photosensitive silver halide may be any photosensitive silver halide, for example silver bromide, silver iodide, silver chloride, silver bromoiodide, chlorobromoiodide. Examples include silver and silver chlorobromide. The light-sensitive silver halide may be added to the emulsion layer by any method as long as the organic silver salt compound functioning as a reducing silver source and the light-sensitive silver halide are in catalytic proximity.

The photosensitive silver halide used in the present invention can be used in the range of 0.005 mol to 0.5 mol, and preferably 0.01 mol to 0.15 mol, per mol of the non-photosensitive reducing silver salt.

The silver halide used in the present invention may be used without modification. However, it may be chemically and spectrally sensitized by methods similar to those used to sensitize conventional wet silver halide or state of the art photothermographic materials. For example, sulfur,
Compounds containing selenium or tellurium, or gold,
Chemical sensitization may be performed using a chemical sensitizer such as a compound containing platinum, palladium, ruthenium, rhodium or iridium, a reducing agent such as tin halide, or a combination thereof. For more information on these methods,
TH James's The Theory of the Photogra Process
phic Process) ”, 4th edition, Chapter 5, pp. 149-169. A suitable chemical sensitization method is Shepard (She
U.S. Pat.No. 1,623,499 to Pard, U.S. Pat.No. 2,399,083 to Waller, U.S. Pat.No. 3,297,447 to McVeigh, and U.S. Pat.No. 3,29 to Dunn.
It is described in No. 7,446.

The photosensitive silver halide may be spectrally sensitized with various known dyes which spectrally sensitize silver halide. Non-limiting examples of sensitizing dyes that can be used include cyanine dyes, merocyanine dyes, complex cyanine dyes, complex merocyanine dyes, all-polar cyanine dyes, hemicyanine dyes, styryl dyes, and hemioxanol dyes. Of these dyes, cyanine dyes,
Merocyanine dyes and complex merocyanine dyes are particularly useful.

A suitable amount of sensitizing dye to be added is generally about 10 ^-10 to 10 ^-1 mol, and preferably about 10 ^-8 to 10 ^-3 mol, per mol of silver halide.

Non-Photosensitive Reducing Silver Source Material The non-photosensitive reducing silver source can be any material containing a source of reducing silver ions. Silver salts of organic acids, particularly silver salts of long-chain aliphatic carboxylic acids are preferred. The chains are typically 10 to 3
It contains 0, preferably 15 to 28 carbon atoms. Complexes of organic or inorganic silver salts in which the ligand has a silver ion total stability constant of 4.0 to 10.0 are also useful in the present invention.

The organic silver salt which can be used in the present invention is relatively stable to light, but when heated to 80 ° C. or higher, the silver salt is exposed in the presence of an exposed photocatalyst (eg silver halide) and a reducing agent. It is a silver salt that forms an image.

Suitable organic silver salts include silver salts of organic compounds having a carboxyl group. Preferred examples thereof include silver salts of aliphatic carboxylic acids and silver salts of aromatic carboxylic acids. Preferred examples of silver salts of aliphatic carboxylic acids include silver behenate, silver stearate, silver oleate,
Examples thereof include silver laurate, silver caproate, silver myristate, silver palmitate, silver maleate, silver fumarate, silver tartrate, silver furoate, silver linolenate, silver butyrate and silver camphorate, and mixtures thereof. A silver salt substituted with a halogen atom or a hydroxyl group can also be effectively used. Preferred examples of silver salts of aromatic carboxylic acids and other carboxyl group-containing compounds include silver benzoate and silver-substituted benzoic acid (for example, 3,
5-Dihydroxybenzoate, silver o-methylbenzoate, silver m-methylbenzoate, silver p-methylbenzoate, silver 2,4-dichlorobenzoate, silver acetamide benzoate, silver p-phenylbenzoate, etc.) , Silver gallate, silver tannate, silver phthalate, silver terephthalate, silver salicylate, silver phenylacetate, silver pyromellitic acid, 3-carboxymethyl-4-methyl-4-triazoline as described in US Pat. No. 3,785,830. -2-Thion silver salt or similar, and U.S. Pat.
There may be mentioned silver salts of aliphatic carboxylic acids containing a thioether group as described in No. 663.

Silver salts containing mercapto or thione groups and their derivatives may be used. Preferred examples of these compounds include silver salt of 3-mercapto-4-phenyl-1,2,4-triazole, silver salt of 2-mercaptobenzimidazole, silver salt of 2-mercapto-5-aminothiadiazole, 2 -
(2-ethyl glycol amide) benzothiazole silver salt,
Silver salt of thioglycolic acid (eg, silver salt of S-alkyl-thioglycolic acid (wherein the alkyl group has 12 to 22 carbon atoms) as described in Japanese Patent Application No. 48-28221), silver of dithioacetic acid Silver salt of dithiocarboxylic acid such as salt, silver salt of thioamide, silver salt of 5-carboxy-1-methyl-2-phenyl-4-thiopyridine, silver salt of mercaptotriazine, silver salt of 2-mercaptobenzoxazole, USA A silver salt as described in Patent No. 4,123,274, for example, a silver salt of a 1,2,4-mercaptothiazole derivative (3-amino-5-benzylthio-1,2,
4-thiazole silver salt, etc.), thione compound silver salt (eg, 3- (2-carboxyethyl) -4-methyl-4-thiazoline-2-thione silver salt as described in US Pat. No. 3,201,678) Is mentioned.

Further, a silver salt of a compound containing an imino group may be used. Preferred examples of these compounds are silver salts of benzothiazole and their derivatives, such as those described in Japanese Patent Publication Nos. 30270/69 and 18146/70, such as methyl-benzotriazole. Silver salt of benzothiazole, silver salt of halogen-substituted benzotriazole such as 5-chloro-benzotriazole, 1,2,4-triazole, silver of 1H-tetrazole as described in US Pat. No. 4,220,709. Examples thereof include silver salts of salts, imidazoles and imidazole derivatives.

Using a silver half soap which is an equimolar blend of silver behenate and behenic acid, prepared by precipitating from a commercially available aqueous solution of the sodium salt of behenic acid, in which about 14.5% silver is detected. It was also found to be convenient and to give a preferred example. The transparent sheet material made of transparent film backing requires a transparent coating, which contains no more than about 4 or 5% free behenic acid and about 25.2% silver is detected silver behenate. You may use full soap.

Methods of making silver soap dispersions are well known in the art, Research Disclosure, April 1983 (22812), Research Disclosure 1
October 983 (23419) and U.S. Pat. No. 3,985,565.

The silver halide may be preformed by any means, for example as described in US Pat. No. 3,839,049. Methods for preparing these silver halides and organic silver salts and methods for blending them are described in Research Disclosure No. 170-29, Japanese Patent Application Nos. 50-32928 and 51-42529, U.S. Pat. It is described in Japanese Patent Application Nos. 49-13224 and 50-17216.

In the material of the present invention, the preformed silver halide emulsion may or may not be washed to remove soluble salts. In the latter case, soluble salts may be removed by cooling and leaching, or the emulsion may be cohesively washed. This is Hewittson (H
ewitson et al., U.S. Pat.No. 2,618,556, Yutz
y) et al. U.S. Pat.No. 2,614,928, Yackel U.S. Pat.No. 2,565,418, Hart et al. U.S. Pat.
41,969, and Waller et al. U.S. Pat.
By means described in No. 489,341. The silver halide grains may have any crystal habit, including but not limited to
Cube, tetrahedron, orthorhombic system, plate shape, laminated shape, platelet shape and the like can be mentioned. The silver halide grains may have a uniform ratio of halogens throughout, and may, for example, have a graded halogen content in which the ratio of silver bromide to silver iodide varies continuously, Alternatively, they may be core-shell type with a discontinuous core with one halogen ratio and a discontinuous shell with another halogen ratio.

A halogen-containing compound is added to the organic silver salt,
It is also effective to use an in-situ method which consists of partially converting the silver of the organic silver salt to silver halide.

The silver halide and non-photosensitive, reducible silver source material that forms the starting point for development should be in reactive association. By "reactive association" is meant that they should be in the same layer, adjacent layers, or layers separated from each other by an intermediate layer having a thickness of less than 1 [mu] m. The silver halide and the non-photosensitive, reducible silver source material are preferably present in the same layer.

In accordance with the present invention, photothermographic emulsions containing preformed silver halide may be sensitized with a chemical sensitizer as described above or with a spectral sensitizer.

The reducible silver source material generally comprises 15-70% by weight of the emulsion layer. It is preferably contained in an amount of about 30 to 55% by weight of the emulsion layer.

Reducing Agent for Non-Photosensitive Reducing Silver Source The reducing agent for the organic silver salt may be any material, preferably an organic material capable of reducing silver ions to metallic silver. Conventional photographic developers such as phenidone, hydroquinones, and catechol are useful, but hindered phenol reducing agents are preferred.

Many reducing agents have been disclosed in dry silver systems and include amidoximes (eg, phenylamidooxime, 2-thienylamidooxime and
p-phenoxyphenylamide oxime), azines (eg 4-hydroxy-3,5-dimethoxybenzaldehyde azine), combinations of aryl carboxylic acid arylhydrazines and ascorbic acid (eg 2,2'-bis (hydroxymethyl)) Propionyl-b-phenylhydrazine in combination with ascorbic acid), polyhydroxybenzene in combination with hydroxyamine, reductone and / or hydrazine in combination (eg hydroquinone with bis (ethoxyethyl) hydroxyamine, piperidinohexose reductone or formyl). -4-methylphenyl-hydrazine), hydroxamic acids (eg phenylhydroxamic acid, p-hydroxyphenylhydroxamic acid,
And o-alanine-hydroxamic acid), combinations of azines and sulfonamidephenols (eg phenithiazine and 2,6-dichloro-4-benzenesulfonamidephenol), cyanophenylacetic acid derivatives (eg ethyl
-a-cyano-2-methylphenylacetic acid, ethyl-a-cyanophenylacetic acid), bis-o-naphthols (eg 2,2'-dihydroxy-1-binaphthyl, 6,6'-dibromo-2,2 '-Dihydroxy-1,1'-binaphthyl, and bis (2-hydroxy-1-naphthyl) methane), bis-o-naphthol and 1,
Combination with 3-dihydroxybenzene derivative (eg
2,4-dihydroxybenzophenone or 2,4-dihydroxyacetophenone), 5-pyrazolones (eg 3-methyl)
1-phenyl-5-pyrazolone), reductones (dimethylaminohexose reductone, anhydrous dihydroaminohexose reductone, and anhydrous dihydro-piperidone-hexose reductone), sulfamide phenol reducing agents (eg 2, 6-dichloro-4-benzenesulfonamidophenol, and p-benzenesulfonamidophenol), 2-phenylidene-1,3-dione and the like, chromanes (eg 2,2-dimethyl-7-t-butyl) -6-
Hydroxychroman), 1,4-dihydropyridines (eg 2,6-dimethoxy-3,5-dicarbetoxy-1,4-dihydropyridine), bisphenols (eg bis (2-hydroxy-3-t-butyl-5-methyl) Phenyl) methane, 2,2-bis (4-
(Hydroxy-3-methyl-phenyl) propane), 4,4-ethylidene-bis (2-t-butyl-6-methyl-phenol), and 2,2-bis (3,5-dimethyl-4-hydroxy-phenyl) ) Propane, 1,1-bis (2-hydroxy-3,5-dimethylphenyl)-
3,5,5-trimethylhexane, ascorbic acid derivatives (eg 1-ascorbyl palmitate, ascorbyl stearate) and unsaturated aldehydes and ketones (eg benzyl and diacetyl), 3-pyrazolidones,
And certain indane-1,3-diones.

The reducing agent should be 1 to 12% by weight of the image forming layer. In multi-layer constructions, when the reducing agent is added to the other layers of the emulsion layer, a slightly higher proportion,
About 2-15% by weight tends to be more desirable.

Binder The binder is preferably sufficiently polar to hold the other components of the emulsion in solution. Binders are polymeric materials such as natural and synthetic resins such as gelatin, polyvinyl acetals, polyvinyl chloride, polyvinyl acetate, cellulose acetate, polyolefins, polyesters, polystyrenes, polyacrylonitrile, polycarbonates, methacrylate copolymers, maleic anhydride. Ester copolymer, butadiene-
It is preferably selected from styrene copolymers and the like. Copolymers, such as terpolymers, are also included in the definition of polymer. Polyvinyl acetals such as polyvinyl butyral and polyvinyl formal, and vinyl copolymers such as polyvinyl acetate and polyvinyl chloride are
Particularly preferred. The binders may be used individually or in combination with one another. The binder may be hydrophilic or hydrophobic, with hydrophobic being preferred.

The binder is generally about the emulsion layer.
Used in an amount of 20 to about 80% by weight, and preferably about 30 to 55% by weight. If the proportions and activities of the constituents require special development times and temperatures, the binder should be able to withstand those conditions. Generally, the binder does not decompose at 200 ° F (90 ° C) for 30 seconds or does not lose its structural integrity and does not decompose at 300 ° F (149 ° C) for 30 seconds, or It is more preferred not to lose structural integrity.

If desired, two or more of these polymers may be used in combination. Such a polymer is used in an amount sufficient to carry the components dispersed therein, that is, within the effective range of its function as a binder. The effective range can be appropriately determined by those skilled in the art.

Dry Silver Formulations Formulations for photothermographic emulsion layers include binders, photosensitive silver halides, non-photosensitive reducible silver sources, reducing agents for non-photosensitive reducible silver sources (eg leuco dyes if desired). , And optional additives can be prepared by dissolving and dispersing in an inert organic solvent such as toluene, 2-butanone or tetrahydrolane.

The use of "toners" or their derivatives which improve the image is also highly desirable but not essential to the element. Toners are 0.01 to 10% by weight, preferably 0.1 to 10% by weight of the emulsion layer.
May be included in an amount of. Toners are known materials in the photothermographic industry, for example, US Pat.
254, 3,847,612 and 4,123,282.

Examples of toners include phthalimide and N-
Hydroxyphthalimide, cyclic imides such as succinimide, pyrazolin-5-ones, and quinazolinone, 1-phenylurazole, 3-phenyl-2-pyrazolin-
5-one, quinazoline and 2,4-thiazolidinedione, naphthalimides (eg N-hydroxy-1,8-naphthalimide), cobalt complexes (eg cobalt hexaminetrifluoroacetate), mercaptans (eg 3-mercapto-1) , 2,4-triazole, 2,4-dimercaptopyrimidine, 3-mercapto-4,5-diphenyl-1,2,4-triazole and 2,5-dimercapto-1,3,4-thiadiazole), N-
(Aminomethyl) aryl dicarboximides (eg
(N, N-dimethyl-aminomethyl) phthalimide, and N-
(Dimethylaminomethyl) -naphthalene-2,3-dicarboximide), and combinations of block pyrazoles, isothiuronium derivatives and certain photobleaches (eg N, N'-hexamethylene-bis (1-carbamoyl-3) , 5-Dimethyl-pyrazole), 1,8- (3,6-diaza-octane) bis (isothiuronium) -trifluoroacetic acid and 2- (tribromomethylsulfonylbenzothiazole)), and merocyanine dyes (eg 3 -Ethyl-5-((3
-Ethyl-2-benzothiazolinylidene) -1-methyl-ethylidene) -2-thio-2,4-o-azolidinedione), phthalazine and phthalazine derivatives, phthalazinone, phthalazinone derivatives or metal salts or derivatives thereof (Eg 4- (1-naphthyl) phthalazinone, 6-chlorophthalazinone, 5,7-dimethoxyphthalazinone and 2,3-dihydro-1,4-phthalazinedione), a combination of phthalazinone and phthalic acid derivatives (Eg phthalic acid, 4-methylphthalic acid, 4-nitrophthalic acid, and tetrachlorophthalic anhydride), quinazoline-diones, benzoxazine or naphthoxazine derivatives, as tone modifiers, as well as for in-situ silver halide formation Rhodium complexes that also function as a source of halogen ions (eg, ammonium (III) hexachlororhodate, rhodium bromide) Rhodium nitrate and potassium hexachlororhodate (III)), inorganic peroxides and persulfates (eg ammonium peroxydisulfate and hydrogen peroxide), benzoxazine-2,4-diones (eg 1,3- Benzoxazine-2,4-dione, 8-methyl-1,3-benzoxazine-2,4-dione and 6-nitro-1,3-benzoxazine-2,4-dione), pyrimidines and asymmetric triazine (Eg 2,4-dihydroxypyrimidine, 2-hydroxy-4-aminopyrimidine and azauracil), and tetraazapentalene derivatives (eg 3,6-dimercapto-1,4-diphenyl-1H, 4H-2,
3a, 5,6a-tetraaza-pentalene and 1,4-di (o-chlorophenyl) -3,6-dimercapto-1H, 4H-2,3a, 5,6a-tetraazapentalene).

If desired, additional antifoggants and stabilizers may be added to the hydroxy-phenyl antifoggants of the invention /
It may be used in combination with a stabilizer compound. Suitable antifoggants and stabilizers that can be used include Staud (Sta
ud) U.S. Pat.No. 2,131,038 and Allen U.S. Pat. And mercury salts described in Allen U.S. Pat. No. 2,728,663, Anderson U.S. Pat. No. 3,287,13.
Urazoles described in 5, No. 3,235,652 U.S. Pat.No. 3,235,652, sulfocatechols described in Carrol et al., British Patent No. 623,448, oximes, Jones U.S. Pat. Polyvalent metal salts described in 2,839,405, Herz U.S. Pat.No. 3,220,83
No. 9 thiuronium salts, and Trivel (Trivel
li) U.S. Patent No. 2,566,263 and Damsloder (Dam
Schroder) in U.S. Pat. No. 2,597,915, including palladium, platinum and gold salts. It may also be convenient to add a mercury (II) salt to the emulsion layer as an antifoggant. The preferred mercury (II) salts for this purpose are mercury acetate and mercury bromide.

The emulsions used in the present invention include plasticizers and brighteners, such as polyalcohols (eg, glycerin and diols), such as Milton (M
ilton), of the type described in U.S. Pat. No. 2,960,404), fatty acids or esters (eg, Robins).
s) U.S. Pat. No. 2,588,765 and Duane U.S. Pat. No. 3,121,060), and silicone resins such as those described in DuPont U.K. Pat. No. 955,061.

The photothermographic element may contain an image dye stabilizer. Such image dye stabilizers are described in British Patent Nos. 1,326,889 and U.S. Patents 3,432,300, 3,698,
No. 909, No. 3,574,627, No. 3,573,050, No. 3,764,337 and No. 4,042,394.

The photothermographic element is, for example, a soda (S
awdey) U.S. Pat.No. 3,253,921, Gaspar U.S. Pat.No. 2,274,782, Carroll et al U.S. Pat.
It can be used in photographic elements containing light absorbing materials and filter dyes such as those described in US Pat. No. 2,956,879 to 7,583 and Van Campen.
If desired, the dye may be mordanted as described, for example, in Milton, US Pat. No. 3,282,699.

Photothermographic elements are described in Matte Agents such as starch, titanium dioxide, zinc oxide, silica, polymeric beads (Jelley et al. US Pat. No. 2,992,101 and Lynn US Pat. No. 2,701,245). Types of beads are included).

Photothermographic emulsions are antistatic or conductive layers, eg layers containing soluble salts (chlorides, nitrides, etc.),
Evaporated metal layers, including layers containing ionic polymers such as those described in Minsk U.S. Pat.Nos. 2,861,056 and 3,206,312 or insoluble inorganic salts such as those described in Trevoy U.S. Pat. obtain.

The photothermographic dry silver emulsion of the present invention may be composed of one or more layers on a support layer. Single layer constructions should include silver source materials, silver halide, developers, and binders with optional materials such as toners, coating aids, and other auxiliaries. A two-layer structure should have the silver source and silver halide in one emulsion layer (usually the layer adjacent to the support layer) and have the other ingredients in the second layer or in both layers. Although good, a two-layer construction consisting of a single emulsion layer coating containing all the components and a protective topcoat is also conceivable. Multicolor photothermographic dry silver constructions may include these two layer sets for each color, or all components in a single layer, US Pat.
It may be included as described in No. 708,928. In the case of multi-layer multicolor photothermographic elements, various functional or non-functional barrier layers are generally used between the various photosensitive layers as described in U.S. Pat.No. 4,460,681. Keep the emulsion layers separate from each other.

Development conditions will vary with the construction used, but typically the imagewise exposed material is processed at a suitable elevated temperature, such as from about 80 ° C to about 100 ° C, preferably from about 110 ° C to about 100 ° C.
This involves heating at 150 ° C. for a sufficient time, generally 1 second to 2 minutes.

In some methods, development is carried out in two stages. Thermal development is about 1 at higher temperatures, eg about 150 ° C.
It is carried out for 0 seconds, followed by thermal diffusion in the presence of a transfer solvent at a lower temperature, for example 80 ° C. A second heating step at lower temperatures prevents further development and allows the already formed dye to diffuse from the emulsion layer to the receptor layer.

The photothermographic emulsion used in the present invention may be coated with various coating methods (for example, wire winding rod coating, dip coating, air knife coating,
Curtain coating or extrusion coating using hoppers of the type described in US Pat. No. 2,681,294). If desired, two or more layers may be applied simultaneously by methods such as those described in US Pat. No. 2,761,791 and British Patent No. 837,095. The wet thickness of a typical emulsion layer may be from about 10 to about 100 μm, and the layer may be dried in forced air at a temperature range of 20 ° C. to 100 ° C. MacBeth Color Densitometer
or Densitometer) TD504 type (using a complementary color filter to the dye color)
It is desirable to choose the layer thickness to provide a maximum image density above 0.2, more preferably in the range 0.5 to 5.0.

In addition, the formulation may be spray dried or encapsulated to produce solid particles. The solid particles can then be dispersed in a second, possibly different binder, and then coated on a support.

Formulations for the emulsion layer may include coating aids such as fluorinated aliphatic polyesters.

A barrier layer, preferably of polymeric material, may be included in the photothermographic element of this invention. The polymer for the material of the barrier layer may be selected from natural and synthetic polymers such as gelatin, polyvinyl alcohols, polyacrylic acids, sulfonated polystyrene and the like. The polymer may optionally be blended with barrier aids such as silica.

A backing layer having a heat-resistant layer on the backside may be used in a color photothermographic imaging system as shown in US Pat. Nos. 4,460,681 and 4,374,921.

[0058]

【Example】

Example 1 4 mil (0.10 mm) polyethylene terephthalate (PE
T) Six samples of film (3M, for photographic film support layers) were cut into 12 x 36 inch (30.5 x 91.4 cm) pieces. Three of these samples were untreated and served as controls. Three samples in a forced air oven for 5 minutes, 1
It was calcined at 75 ° C. From one of the control samples, three 35 mm wide strips were cut in both the machine and transverse directions (6 strips total). Three 35 mm wide strips were cut from one of the fired samples in both the machine and transverse directions. Ink on all samples
Two spots marked about 20.3 cm apart were marked. Accurate measurements were made using a Confirmer traveling microscope. The sample was heated at 150 ° C for 15 minutes. After heating, the length between the ink spots was measured again. The calcined sample had an average strain of -0.074% in the machine direction and -0.060% in the cross direction. -0.655% and -0.326 in the machine and transverse directions, respectively, in the control sample
These distortions are small and well-balanced compared to the% distortions.

Example 2 A sample was prepared as in Example 1 except that instead of heating at 150 ° C. for 15 minutes, the sample was passed through a thermal drum processor of the type used to thermally develop photothermographic elements. It took about 15 seconds for the sample to pass through the processor set at 121 ° C. The control sample had strains of -0.081% and 0.056% in the machine and transverse directions, respectively. The fired samples underwent 0.017% and 0.025% strain in the machine and transverse directions, respectively. Again, the strain was less and more balanced in the fired sample.

Example 3 Prior to being cut into 3 × 35 mm strips, as disclosed in US patent application Ser. No. 08 / 199,114 (filed Feb. 22, 1994), the film support layer was spaced 0.114 mm apart. A sample was prepared as in Example 1 except that the photothermographic emulsion was knife coated. Also, US Patent Application No. 08/1
The protective topcoat disclosed in 99,114 was knife coated at 0.038 mm intervals. The coating was dried at about 83 ° C for 4 minutes. The points of measurement were made using a metal punch. This is because the applied material becomes dark black after development, making it difficult to read ink spots.
The sample was passed through a thermal drum processor of the type used to thermally develop photothermographic elements. It takes about 15 minutes for the sample to pass through the drum processor set at 121 ℃.
It took seconds. The control sample had an average strain of -0.085% and 0.034% in the machine and transverse directions, respectively.
The fired sample is in the machine direction and the transverse direction,
It showed lower, more balanced strains of 0.018% and 0.003%.

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Sudarshan Kumar Bateja United States 55144-1000 3M Center, Saint Paul, Minnesota (No address)

Claims (6)

[Claims] 1. A heat-developable imaging element which develops at temperatures of from 100 ° C. to 150 ° C., comprising a heat-developable imaging composition coated on a polymeric support, said polymeric support having a low tension and Higher than the glass transition temperature of the polymer, lower than the melting point of the polymer, and the development temperature plus 30 ℃
A heat-developable imaging element in which the polymeric support is dimensionally stable at the development temperature by heat treatment at a temperature not lower. 2. The element according to claim 1, wherein the support is heat treated for a time required for the support to reach the heat treatment temperature plus more than 5 seconds. 3. The tension on the polymer support during heat treatment is
The element according to claim 1, which is lower than 1.4 × 10 ⁶ N / m ² . 4. The element according to claim 1, wherein the heat-developable image forming composition is a photothermographic composition comprising a photosensitive silver halide, a non-photosensitive reducing silver source, a silver reducing agent, and a binder. . 5. A heat developable imaging element according to any of claims 1 to 4 wherein the element undergoes less than 0.03% strain during heat development. 6. A semi-crystalline polymer film is heated at a temperature of 165 ° C. or higher for a period of time longer than the time required for the film itself to reach 165 ° C., and then a photosensitive silver halide, A method for producing a photothermographic element, which comprises the step of applying a photothermographic emulsion comprising a photosensitive reducing silver source, a reducing agent for silver and a binder.