JP2004161004A - Stabilizer for using in substantially non-photosensitive thermographic recording material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a stabilizer for using in a substantially non-photosensitive thermographic recording material suitable for use without exerting a bad influence upon an image color tone in a high throughput thermographic printer. <P>SOLUTION: This substantially non-photosensitive black and white monochrome sheet thermographic recording material consists of a support and thermosensitive elements including a substantially non-photosensitive organic silver salt, an organic reducing agent for the silver salt put under a thermal action relationship therewith, a binder, a 1-phenyl-5-mercaptotetrazole compound substituted by a substituent including an aryl group allowing to be substituted with a phenyl group when occasion demands, and at least one kind of stabilizers selected from the group consisting of compounds represented by the general formula. <P>COPYRIGHT: (C)2004,JPO

Description

  The present invention relates to stabilizers for use in substantially light-insensitive thermographic recording materials.

  Thermography is an image-forming method that includes a heating step, and thus, image-forming methods include photothermography, which includes image-wise exposure, and image-forming methods include direct thermal methods, which include an image-wise heating step. In direct thermal printing, a visible image pattern is formed by image-wise heating of the recording material.

Patent Document 1 has at least one photosensitive silver halide-containing layer on a support, and further has a general formula (I):
X-(-(J) _m- F) _n (I)
Wherein X is the residue of a development inhibitor; J is a divalent linking group; F is the diffusivity of the compound of formula (I) or its silver salt or complex during thermal development. An immobilizing group that can be lowered; m is 0 or 1; n is an integer from 1 to 3]
Discloses a thermally developable photosensitive material containing a compound represented by the formula: U.S. Pat. No. 6,052,072 discloses the following 1-phenyl-5-mercaptotetrazole compounds in which the phenyl group is optionally substituted with a substituent that contains an aryl group:

Patent Document 2 includes a photographic structure layer including a support and at least one layer containing photosensitive silver halide provided thereon, wherein the photographic structure layer has the formula (1): X ₁ -L _1- A [wherein, X ₁ represents a residue of a photographic inhibitor, L ₁ is a mere bond hand or a divalent group, and A is a hydrogen atom, an amino group, a hydroxyl group, a carboxyl group. Or a salt thereof, a sulfo group or a salt thereof and a sulfin group or a salt thereof], and a general formula (2): X ₂ -L ₂ -B wherein X ₂ represents a residue of a photographic inhibitor, L ₂ is a divalent group, and B is a ballast group], which discloses a thermally developable photosensitive material. US Pat. No. 5,073,086 discloses the following 1-phenyl-5-mercaptotetrazole compounds in which the phenyl group is optionally substituted with a substituent containing an aryl group:

  U.S. Pat. No. 6,086,097 discloses exposing a first photosensitive sheet material image-wise, wetting at least one of the first photosensitive sheet material and a second non-photosensitive sheet material with an aqueous liquid, Disclosed is a method of forming a color image by photographic dye diffusion wherein the materials are heated together at 50 ° C. to 100 ° C. with their coated surfaces in contact and then separated, said first sheet material comprising: The layer support contains at least one light-sensitive silver halide emulsion layer and at least one non-diffusible color compound, which can decompose imagewise during the development process to release diffusible dyes. Preferably, the second sheet material contains a salt of a strong organic base and a weak acid, wherein the first sheet material has the following formula I and II:

[Wherein R ¹ represents hydrogen, alkyl having up to 6 carbon atoms, halogen, hydroxy, alkoxy or a substituent which together form a fused benzene ring]
as well as

Wherein R ² represents a group capable of splitting during the process of development of the material, R ³ represents hydrogen, halogen, alkyl having up to 4 carbon atoms, alkoxy, carboxy, carbalkoxy, carbonamide or sulfone Shows amide]
Are included. Patent Document 3 also discloses the following 1-phenyl-5-mercaptotetrazole compound in which a phenyl group is substituted with a substituent:
SH-14:

Patent Document 4 discloses (a) a reducible silver source, (b) a photocatalyst, (c) a reducing agent, (d) a binder, and (e) at least one of the following general formulas (I): XL ₁ -D discloses a photothermographic material comprising a compound of formula (D), wherein D is an electron donative group of atoms, provided that D is a hydrazino group that is not part of a semicarbazide group. No oxo group is substituted to the carbon atom by a carbon atom directly bonded to the nitrogen atom of hydrazine, and X can promote adsorption to silver halide. L ₁ is a valence bond or a linking group. US Pat. No. 6,059,086 discloses the following 1-phenyl-5-mercaptotetrazole compounds in which the phenyl group is optionally substituted with a substituent containing an aryl group:

  US Pat. Nos. 6,026,026; 6,026,026; and 4,069,086, all of which are incorporated herein by reference, wherein a phenyl group is optionally substituted with a substituent containing an aryl group which may be optionally substituted. Discloses the use of the compound. However, the technology of a substantially light-insensitive thermographic material containing a substantially light-insensitive organic silver salt is the same as that of a photothermographic material containing a substantially light-insensitive organic silver salt. In some cases, the images are substantially different, regardless of whether the images result from the reduction of the organic silver salt. However, this is because the realization of the species that catalyzes this reduction is completely different, in the case of photothermographic recording materials the image-wise of the photosensitive silver halide-containing photo-addressable thermally developable element. Exposure, and in the case of thermographic recording materials an external similarity that masks the image-wise heating of a heat-sensitive element that does not contain photosensitive silver halide. The differences in this technique are further accentuated by the nature of the components used in the two types of materials, the most significant difference being the absence of light-sensitive silver halide and spectral sensitizer in substantially light-insensitive thermographic recording materials. However, it is also reflected in the different reducing agents used, and in the substantially light-insensitive thermographic recording materials, stronger reducing agents are used, as well as in different stabilizers, different toning agents and the like. Furthermore, the thermal development method itself is heated for several seconds (eg 10 seconds) at a temperature below 150 ° C. in the case of photothermographic recording materials, whereas in the case of substantially non-photosensitive thermographic recording materials. Is significantly different in that the material is image-wise heated at a much higher temperature for milliseconds (eg, 10-20 milliseconds). Furthermore, while thermal development in a substantially light-insensitive thermographic recording material involves the liquid crystal phase of an organic silver salt, in the thermal development step in the case of a photothermographic recording material, the same organic silver salt can be used. This is not the case. The realization of neutral image tones is a significant problem in the case of substantially light-insensitive thermographic recording materials due to the very short heating times, but in photothermographic recording materials much longer heating times are required. So it's not that much of a problem.

  US Pat. No. 6,037,097 discloses a donor element comprising a support layer containing a donor layer containing (i) a binder and a heat transferable reducing agent capable of reducing a silver source to metallic silver, and (ii) heat in the presence of a reducing agent. Sources, binders and benzotriazoles, heterocyclic mercaptans, sulfinic acids, 1,3,4-triazo-indinolines, 1,3-dinitroaryl compounds, 1,2,3 -Discloses a thermal imaging system comprising a receiving element comprising on a support a receiving layer comprising a stabilizer selected from the group consisting of triazoles, phthalic acid and phthalic acid derivatives. Patent Document 5 discloses that preferred heterocyclic mercaptans have the following general formula (C):

And the following 1-phenyl-5-mercapto-tetrazole compounds are disclosed:

U.S. Pat. No. 5,064,086 includes a support and a heat-sensitive element containing a substantially light-insensitive organic silver salt, an organic reducing agent and a binder therefor in thermal operational relation thereto, the heat-sensitive element further comprising: -Containing an unsaturated carbocyclic or heterocyclic stabilizer compound substituted with a SA group, wherein A forms a hydrogen, a counter ion to compensate for the negative charge of the thiolate group or a symmetric or asymmetric disulfide it and the recording material is a group to produce a print with a 2.3 greater gradation numbers are defined as the quotient of the fraction _{(2.5-0.1) / (E 2.5 -E} 0.1) Where E _2.5 is the energy in joules applied at a 87 μm × 87 μm dot area of the imaging layer that produces an optical density value of 2.5, and E _0.1 is an optical density value of 0.1 Spawn A substantially non-photosensitive monosheet recording material characterized by the energy in joules applied in the dot area of the image forming layer material. Patent Document 6 discloses the following 1-phenyl-5-mercapto-tetrazole compound:

  US Pat. No. 5,077,086 discloses a color-forming amount of finely divided colorless solid noble metal or iron salt of an organic acid distributed in a carrier composition; noble metal or iron salt at thermal copying and printing temperatures. A color developing amount of a cyclic or aromatic organic reducing agent capable of reacting; and a color-forming layer containing an image-toning agent; (a) a carrier composition comprising a substantially water-soluble polymeric carrier and a noble metal; Alternatively, a multi-layer heat-sensitive material is disclosed, comprising a dispersant for the iron salt and (b) the material comprising a protective overcoat for the color-forming layer. Further, Patent Document 7 discloses that suitable antifoggants include mercaptobenzotriazole, chromate, oxalate, citrate, carbonate, benzotriazole (BZT), 5-methylbenzotriazole, and 5,6-dimethylbenzotriazole. , 5-bromobenzotriazole, 5-chlorobenzotriazole, 5-nitro-benzotriazole, 4-nitro-6-chlorobenzotriazole, 5-nitro-6-chlorobenzotriazole, 4-hydroxy-6-methyl-1, 3,3a, 7-tetraazaindene, benzimidazole, 2-methylbenzimidazole, 5-nitrobenzimidazole, 1-phenyl-5-mercaptotetrazole, 2-mercaptobenzimidazole, 2-mercaptobenzothiazole, 2-mercaptobenz Oxa 2-mercaptothiazoline, 2-mercapto-4-methyl-6,6'-dimethylpyrimidine, 1-ethyl-2-mercapto-5-amino-1,3,4-triazole, 1-ethyl-5 Well-known photographs such as mercapto-1,2,3,4-tetrazole, 2,5-dimercapto-1,3,4-thiodiazole, 2-mercapto-5-aminothiodiazole, dimethyldithiocarbamate and diethyldithiocarbamate It discloses that it is an antifoggant.

US Pat. No. 5,077,086 discloses, on at least one surface thereof, a non-photosensitive organic silver salt; a reducing agent for silver ions; a binder; a toning agent; and a dye absorbing radiation in the wavelength range from 750 to 1100 nm. Discloses a thermographic imaging element comprising a substrate coated with a thermographic imaging system comprising at least one layer comprising a non-photosensitive organic silver salt wherein the at least one layer comprising a non-photosensitive organic silver salt is 0.1. Exposure to 10-2.0 Joules / cm ² of the radiation within 0.20-200 microseconds results in image densities greater than about 1.0. U.S. Pat. No. 6,077,064 does not disclose a stabilizer against light effects, but does mention the optional introduction of benzotriazole in a thermographic imaging element, but only exemplifies the introduction of benzotriazole.

Substantially light-insensitive thermographic recording materials contain image-forming components both before and after imaging, and undesired imaging can occur during storage prior to printing and during inspection, e.g., by a radiologist. Both in prints exposed to light on the light box in between must be hindered. Furthermore, such stabilization must be performed without adversely affecting the image quality, especially the image tone. Thermographic printers with very high throughput are being introduced, which requires that the thermographic recording material be able to provide stabilization at such relatively fast throughput without adversely affecting image quality. Therefore, there is a need for stabilizers that meet these requirements.
Prior Documents The following documents related to the patentability of the present invention are known to date:
Patent document 1 published on April 15, 1987
Patent document 2 published on February 24, 1988
Patent Document 3 published on December 21, 1988
Patent Document 5 published on May 22, 1996
Patent document 4 published on April 29, 1998
Patent document 6 published on March 10, 1999
Patent document 9 issued on July 13, 1999
Patent document 7 published on July 21, 1994
Patent document 8 published on April 4, 1996
European Patent Application Publication No. 0218385 EP-A-0256820 European Patent Application Publication No. 0295507 European Patent Application Publication No. 0838822 European Patent Application Publication No. 07131133 European Patent Application Publication No. 0901040 International Publication No. 94/16361 pamphlet WO 96/10213 pamphlet U.S. Pat. No. 5,922,529

Accordingly, one aspect of the present invention is to provide a stabilizer for use in a substantially light-insensitive thermographic recording material suitable for use in high-throughput thermographic printers without adversely affecting image tone. It is.

  Further aspects and advantages of the present invention will become apparent from the description below.

SUMMARY OF THE INVENTION Surprisingly, certain types of 5-mercapto-tetrazole compounds provide CIELAB a * and b * values in substantially light-insensitive thermographic recording materials suitable for use in high-throughput thermographic printers. Has been found to provide effective stabilization without adversely affecting the image tone characterized by L *, a * and b * CIELAB-values were determined by spectrophotometry according to ASTM Norm E179-90 in R (45/0) geometry, using an evaluation according to ASTM Norm E308-90.

  Aspects of the invention include a support and a heat-sensitive element, wherein the heat-sensitive element comprises a substantially light-insensitive organic silver salt, an organic reducing agent therefor in a thermal working relationship therewith, a binder and a phenyl group. A 1-phenyl-5-mercaptotetrazole compound substituted with a substituent containing an aryl group that can be substituted with:

This is accomplished using a substantially light-insensitive black-and-white monosheet thermographic recording material containing at least one stabilizer selected from the group consisting of:

Preferred embodiments of the present invention are disclosed in the detailed description of the invention.
Detailed description of the invention
DEFINITIONS The term alkyl refers to all possible variations for each number of carbon atoms in the alkyl group, ie, 3 carbons: n-propyl and isopropyl; 4 carbons: n-butyl, isobutyl and tert. Tertiary butyl; when the number of carbon atoms is 5, means n-pentyl, 1,1-dimethyl-propyl, 2,2-dimethylpropyl, 2-methyl-butyl and the like.

  The term acyl group as used in disclosing the present invention refers to-(C = O) -aryl and-(C = O) -alkyl groups.

  L *, a * and b * CIELAB-values are defined in ASTM Norm E179-90 in R (45/0) geometry, using an evaluation according to ASTM Norm E308-90.

  Substantially non-photosensitive means not particularly light sensitive.

  Heating, as used herein, in connection with the expression substantially anhydrous conditions, means heating at a temperature of 80-250 ° C. As used herein, the term "substantially water-free condition" refers to a reaction in which the reaction is in approximately equilibrium with water in the air, and the water to induce or promote the reaction is It is not specifically or actively supplied from outside the element. Such conditions are described in T.W. H. James, "The Theory of the Photographic Process", Macmillan, 1997, Fourth Edition, page 374.

Thermal element The term thermal element as used herein is an element that contains all components that contribute to image formation. According to the present invention, the heat-sensitive element contains one or more substantially light-insensitive organic silver salts, one or more reducing agents therefor and a binder therefor in a thermal working relationship therewith. . The element can include a layer system in which the components described above can be dispersed in various layers, except that the substantially light-insensitive organic silver salt is in reactive association with the reducing agent, i.e., During the development process, the reducing agent must be present in such a way that it can diffuse into the particles of the substantially light-insensitive organic silver salt and reduction to silver can take place. Such materials include one or more substantially light-insensitive as disclosed in EP-A-0 736 799, the contents of which are incorporated herein by reference. And / or the possibility of encapsulating one or more organic reducing agents therefor in thermo-responsive microcapsules.

1-Phenyl-5-mercaptotetrazole compound The substantially light-insensitive thermographic recording material of the present invention can contain at least one 1-phenyl-5-mercaptotetrazole compound, wherein the phenyl group is Is substituted with a substituent containing an aryl group which can be substituted by Preferred substituents for the phenyl group, -NHCO- phenyl, -NHCO- (1-naphthyl), - NHCO- (2- naphthyl), - -NHCONH- phenyl, -NHSO ₂ - phenyl, -NHSO ₂ - ( 1-naphthyl), - NHSO ₂ - (2- naphthyl), _- SO 2 NH- phenyl, -CONH- phenyl, -CONH- (1-naphthyl), - CONH- (2- naphthyl), - NHCO- (2 -Thienyl) and -NHCONHCO-phenyl groups. Preferred substituents for the aryl group are a halogen atom, an ester group, an -OCOO-alkyl group, a -NHCOO-alkyl group, a -NHOC-alkyl group, a -CONH-alkyl group, a -S-alkyl group and a mercapto, alkyl, It is selected from the group consisting of alkoxy, nitrile, acyl and nitro groups.

  According to a first embodiment of the substantially light-insensitive black-and-white monosheet thermographic recording material according to the present invention, the phenyl group is substituted with a substituent containing an optionally substituted aryl group. The phenyl-5-mercaptotetrazole compound has the formula (I):

Wherein R ¹ is -NH- (C = O) -Ar, -NH- (C = O) -NH-Ar, -NH- (C = O) -O-Ar, -O- (C = O) -NH-Ar , - (C = O) -NH-Ar, -NH-SO 2 -Ar, -O- (C = O) -Ar, -O- (C = O) -O -Ar, - (C = O) -Ar, - (C = O) -O-Ar, -SO 2 -Ar, be -SO 2 -NH-Ar, or -Ar; Ar is optionally substituted Aryl or heteroaryl group. Preferred substituents for aryl and heteroaryl groups include halogen atoms, ester groups, -OCOO-alkyl groups, -NHCOO-alkyl groups, -NHOC-alkyl groups, -CONH-alkyl groups, -S-alkyl groups, and Includes mercapto, alkyl, alkoxy, nitrile, acyl and nitro groups.

  According to a second embodiment of the substantially light-insensitive black-and-white monosheet thermographic recording material according to the present invention, the phenyl group is substituted with a substituent containing an optionally substituted aryl group. The phenyl-5-mercaptotetrazole compound has the formula (II):

Wherein R ² is -NH- (C = O) -Ar, -NH- (C = O) -NH-Ar, -NH- (C = O) -O-Ar, -O- (C = O) -NH-Ar , - (C = O) -NH-Ar, -NH-SO 2 -Ar, -O- (C = O) -Ar, -O- (C = O) -O -Ar, - (C = O) -Ar, - (C = O) -O-Ar, -SO 2 -Ar, be -SO 2 -NH-Ar, or -Ar; Ar is optionally substituted Aryl or heteroaryl group. Preferred substituents for aryl and heteroaryl groups include halogen atoms, ester groups, -OCOO-alkyl groups, -NHCOO-alkyl groups, -NHOC-alkyl groups, -CONH-alkyl groups, -S-alkyl groups and mercapto groups. , Alkyl, alkoxy, nitrile, acyl and nitro groups.

  According to a third embodiment of the substantially light-insensitive black-and-white monosheet thermographic recording material according to the present invention, the at least one stabilizer comprises:

Selected from the group consisting of:

  A 1-phenyl-5-mercaptotetrazole compound wherein the phenyl group according to the present invention is optionally substituted with a substituent containing an aryl group, and

Can be prepared from readily available starting materials using standard organic chemistry methods known to those skilled in the art and available in reference books such as Houben-Weyl.

  Suitable 1-phenyl-5-mercaptotetrazole (PMT) compounds in which the phenyl group according to the present invention is optionally substituted with a substituent containing an aryl group include:

Organic Silver Salt According to a fourth embodiment of the substantially light-insensitive black-and-white monosheet thermographic recording material of the present invention, the organic silver salt is an organic silver salt-containing organic cation containing a silver cation with a magnesium or iron ion. Not double salt.

  According to a fifth embodiment of the substantially light-insensitive black-and-white monosheet thermographic recording material of the present invention, at least one of the organic silver salts is a substantially light-insensitive silver salt of an organic carboxylic acid.

  According to a sixth aspect of the substantially light-insensitive black-and-white monosheet thermographic recording material of the present invention, at least one of the organic silver salts is a fatty acid whose aliphatic carbon chain preferably has at least 12 C-atoms. Substantially non-photosensitive silver salts of aliphatic carboxylic acids, such as silver laurate, silver palmitate, silver stearate, silver hydroxystearate, silver oleate and silver behenate, which are known as Silver salt is also called "silver soap". Other organic silver salts of organic carboxylic acids, such as those described in GB 1,439,478, such as silver benzoate, can also be used to form thermally developable silver images. it can. As disclosed in EP-A-964300, combinations of various silver salts of organic carboxylic acids can also be used in the present invention.

  The organic silver salt can be dispersed by a standard dispersion method. Ball mills, bead mills, microfluidizers, ultrasonic devices, rotor-stator mixers and the like have been found to be useful in this regard. Mixtures of organic silver salt dispersions prepared by various methods can also be used, for example, to obtain the desired thermographic properties of relatively coarse organic silver salt dispersions and relatively finely divided organic silver salt dispersions. .

According to a seventh aspect of the black-and-white thermographic recording material according to the present invention, the reducing agent comprises at least one O-, N- or C-bound compound as in the case of aromatic di- and tri-hydroxy compounds. Is an organic compound containing an active hydrogen atom. 1,2-dihydroxy-benzene derivatives such as catechol, 3- (3,4-dihydroxyphenyl) propionic acid, 1,2-dihydroxybenzoic acid, gallic acid and esters such as methyl gallate, ethyl gallate, gallic acid Propyl, tannic acid and 3,4-dihydroxy-benzoic acid esters are preferred, and those described in EP-A-0 692 733 and EP-A-0 903 625 are particularly preferred.

  It is also possible to use a combination of reducing agents which, when heated, become a reactive partner in the reduction of one or more substantially non-photosensitive organic silver salts. For example, combinations of sterically hindered phenols with a sulfonyl hydrazide reducing agent as disclosed in US Pat. No. 5,464,738; disclosed in US Pat. No. 5,496,695. Trityl hydrazide and formyl-phenyl-hydrazide as described in U.S. Patent Nos. 5,545,505, 5,545,507 and 5,558,983. Tritylhydrazide and formyl-phenyl-hydrazide as disclosed and various co-reducing agents; as disclosed in U.S. Patent Nos. 5,545,515 and 5,635,339. Acrylonitrile compounds; and 2-substituted malonodias as disclosed in US Pat. No. 5,654,130. Dehydrogenase compound.

Binders of the heat-sensitive element The film-forming binder of the heat-sensitive element is any kind of natural, modified natural or synthetic resin in which at least one organic silver salt can be uniformly dispersed in an aqueous or solvent medium. Alternatively, mixtures of such resins: for example, polymers derived from cellulose derivatives, starch ethers, galactomannans, α, β-ethylenically unsaturated compounds, such as polyvinyl chloride, post-chlorinated polyvinyl chloride, vinyl chloride Made of vinylidene chloride, vinyl chloride and vinyl acetate copolymers, polyvinyl acetate and partially hydrolyzed polyvinyl acetate, polyvinyl alcohol, and polyvinyl alcohol as the starting material. Polyvinyl acetal, preferably Vinyl butyral, copolymers of acrylonitrile and acrylamide, polyacrylates, polymethacrylates, polystyrene and polyethylene or mixtures thereof.

  Suitable water-soluble film-forming binders for use in the thermographic recording material according to the invention are: polyvinyl alcohol, polyacrylamide, polymethacrylamide, polyacrylic acid, polymethacrylic acid, polyvinylpyrrolidone, polyethylene glycol, proteinaceous binder. , Polysaccharides and water-soluble cellulose derivatives. A preferred water-soluble binder for use in the thermographic recording material of the present invention is gelatin.

  The weight ratio of binder to organic silver salt is preferably in the range of 0.2 to 7, and the thickness of the heat sensitive element is preferably in the range of 5 to 50 µm. Binders which do not contain impurities which adversely affect the thermographic properties of the thermographic recording material in which additives or binders such as certain antioxidants (e.g. 2,6-di-tert-butyl-4-methylphenol) are used. Is preferred.

Toner According to an eighth embodiment of the black-and-white monosheet thermographic recording material according to the invention, the heat-sensitive element is capable of obtaining a neutral black image tone at relatively high densities and a neutral gray at relatively low densities. Contains a toning agent.

  According to a ninth embodiment of the black-and-white monosheet thermographic recording material according to the invention, the heat-sensitive element is furthermore a toning agent selected from the group consisting of phthalimides, phthalazinones, benzoxazinediones and naphthooxazinediones, for example, cited. Phthalimides and phthalazinones within the scope of the general formula described in U.S. Pat. No. 4,082,901, the contents of which are incorporated herein by reference; U.S. Pat. No. 3,074,809; 3,446,648 and 3,844,797; and British Patent 1,439,478, U.S. Pat. No. 3,951,660 and U.S. Pat. Complexes of the benzoxazinedione or naphthoxazinedione type as disclosed in US Pat. No. 5,599,647. Containing an expression toner compound.

  According to a tenth embodiment of the substantially light-insensitive black-and-white monosheet thermographic recording material according to the present invention, the substantially light-insensitive thermographic material contains a heat-sensitive element, wherein the heat-sensitive element is phthalazinone, benzo [e]. [1,3] oxazine-2,4-dione, 7-methyl-benzo [e] [1,3] oxazine-2,4-dione, 7-methoxy-benzo [e] [1,3] oxazine-2 , 4-dione and 7- (ethylcarbonato) -benzo [e] [1,3] oxazine-2,4-dione.

Auxiliary antifoggant According to an eleventh aspect of the black-and-white monosheet thermographic recording material according to the present invention, the thermographic recording material further comprises an auxiliary antifoggant to obtain an improved shelf life and reduced fog.

  According to a twelfth embodiment of the black-and-white monosheet thermographic recording material according to the present invention, the thermographic recording material further comprises benzotriazole, substituted benzotriazoles and aromatic polycarboxylic acids such as ortho-phthalic acid, 3-nitro-phthalic acid, It contains an antifoggant selected from the group consisting of chlorophthalic acid, melitic acid, pyromellitic acid and trimellitic acid and their anhydrides.

  According to a thirteenth embodiment of the black-and-white mono-sheet thermographic recording material according to the present invention, the heat-sensitive element further contains an optionally substituted benzotriazole.

Polycarboxylic acids and their anhydrides According to a fourteenth embodiment of the black-and-white monosheet thermographic recording material according to the present invention, the heat-sensitive element further comprises at least one polycarboxylic acid and / or their anhydrides, Contains at least 15 mole percentages relative to all organic silver salts of the singular and in thermal operational relationship therewith. The polycarboxylic acids can be aliphatic (saturated and unsaturated aliphatic and also cycloaliphatic) or aromatic polycarboxylic acids, can be substituted, and leave at least two free carboxylic acids. Or it can be used in anhydrous form or in a partially esterified form under the conditions available for the thermal recording step.

Surfactants and Dispersants Surfactants and dispersants aid in dispersing components that are insoluble in certain dispersion media. The substantially light-insensitive thermographic material used in the present invention is one or more surfactants and / or one or more surfactants, which can be anionic, non-ionic or cationic surfactants. Many dispersants can be included. Suitable dispersants are natural polymeric substances, synthetic polymeric substances and finely divided powders, for example finely divided non-metallic inorganic powders such as silica.

Support According to a fifteenth embodiment of the substantially light-insensitive black monosheet thermographic recording material according to the present invention, the support is transparent or translucent. It is preferably a thin flexible carrier made from a transparent resin film, for example, a cellulose ester such as cellulose triacetate, polypropylene, polycarbonate or a polyester such as polyethylene terephthalate. The support can be in the form of a sheet, ribbon or web, and can be subbed, if necessary, to improve adhesion to the thermosensitive element coated thereon. The support can be dyed or pigmented to give a transparent colored background for the image.

Protective Layer According to a sixteenth aspect of the substantially light-insensitive black-and-white monosheet thermographic recording material according to the present invention, the heat-sensitive element is provided with an outermost protective layer. Generally, this protects the thermal element from atmospheric humidity and surface damage, such as from scratching, and prevents direct contact of the printhead or heat source with the recording layer. Protective layers for heat-sensitive elements that must be in contact with and transported through a heat source under pressure must exhibit resistance to local deformation and excellent sliding properties during transport through the heat source during heating . The outermost sliding layer may comprise dissolved lubricating material and / or particulate material that may optionally protrude from the outermost layer, such as talc particles. Examples of suitable lubricating materials are surfactants, with or without a polymeric binder, liquid lubricants, solid lubricants or mixtures thereof.

Coating Methods The coating of any layer of the substantially light-insensitive thermographic material used in the present invention can be obtained, for example, from Modern Coating and Drying Technology, edited by Edward D.D. Cohen and Edgar B.A. Gutoff, (1992) VCH Publishers Inc. , 220 East 23rd Street, Suite 909 New York, NY 10010, USA. The coating can be applied from an aqueous or solvent medium to the dried, partially dried or undried layer.

Thermographic Processing Thermographic imaging involves the use of an infrared heat source in an analogous manner by direct exposure through the image or reflection from the image, or, preferably, in the case of substantially light-insensitive thermographic materials containing infrared-absorbing compounds. By using, for example, a Nd-YAG laser or other infrared laser, or by direct thermal imaging using a thermal head, by applying the heat image-wise, in a digital manner, pixel by pixel.

In thermal printing, image signals are converted to electrical pulses and then selectively transmitted to a thermal printhead via a driver circuit. Thermal printheads consist of a microscopic heat resistor component, which converts electrical energy to heat via the Joule effect. The operating temperature of a typical thermal print head is in the range of 300-400 ° C., the heating time per pixel can be less than 1.0 millisecond, and the pressure between the thermal print head and the recording material The contact is at a pressure of, for example, 200-1000 g / linear cm, ie 5000-50,000 g / cm ^{2 for} a 200-300 μm contact area (nip) to ensure excellent heat transfer.

  If the outermost layer on the same side of the support as the thermal element is not a protective layer, contact the imagewise heating of the recording material with the thermal printhead to avoid direct contact between the thermal printhead and this outermost layer. It can be performed through a resin sheet or web that is removable but removable and does not allow transfer of the recording material therefrom during heating.

  Activation of the heating component can be power-modulated or pulse-length modulated at a constant power. EP-A-654 355 discloses an image forming method by image-wise heating using a thermal head having a heating part to which a voltage can be applied, in which activation of the heating part becomes a duty cycle ( Duty cycled). EP-A-622217 discloses an imaging method using a direct thermal imaging element which produces an improvement in continuous tone reproduction.

  The image-wise heating of the recording material can also be carried out using an electrically resistive ribbon introduced into the material. The image-wise or pattern-wise heating of the recording material can also be carried out using pixel-wise modulated ultrasound.

INDUSTRIAL APPLICATION Transparency for use in thermographic imaging in reflective printing and especially in the medical diagnostic field where black-imaged transparencies are widely used in tests operated with light boxes Can be used to create

In the following, the present invention is illustrated by comparative examples and examples of the present invention. The percentages and ratios given in these examples are by weight unless otherwise stated.
Subbing layer on emulsion side of support:
The undercoat layer number 01 has the composition:

Having.

  The undercoat layer number 02 has the composition:

Having.

Ingredients in other thermosensitive elements of the above ingredients:
BL5HP = S-LEC BL5HP, polyvinyl butyral from Sekisui;
Oil = BAYSILON, silicone oil from BAYER;
VL = DESMODUR VL, 4,4′-diisocyanatodiphenylmethane from BAYER;
Reducing agent:
R01 = 3,4-dihydroxybenzonitrile;
R02 = 3,4-dihydroxybenzophenone;
Toning agent:
T01 = 7- (ethylcarbonato) -benzo [e] [1,3] oxazine-2,4-dione;
T02 = 7-methyl-benzo [e] [1,3] oxazine-2,4-dione;
Stabilizer:
S01 = Glutaric acid S02 = Tetrachlorophthalic anhydride S03 = Benzotriazole S04 =

  PMT-C1 = 1-phenyl-5-mercapto-tetrazole

Ingredients in protective layer:
ERCOL ^™ 48 20 = polyvinyl alcohol from ACETEX EUROPE;
LEVASIL ^™ VP AC 4055 = A 15% aqueous dispersion of colloidal silica from BAYER AG whose acid groups are mainly neutralized with sodium ions and have a specific surface area of 500 m ² / g was converted to ammonium salts;
ULTRAVON ^™ W = 75-85% concentrate of sodium arylsulfonate from Ciba Geigy converted to acid form by passage through an ion exchange column;
SYLOID ^™ 72 = silica from Grace;
SERVOXYL ^™ VPDZ 3/100 = SERVO DERDEN B. V. Mono [isotridecyl polyglycol ether (3EO)] phosphate from;
SERVOXYL ^TM VPAZ 100 = SERVO DELDEN B. V. A mixture of monolauryl and dilauryl phosphates from
MICROACE TALC P3 = Indian talc from NIPPON TALC;
RILANIT ^™ GMS = glycerin mono tallow acid ester from HENKEL AG TMOS = tetramethyl orthosilicate hydrolyzed in the presence of methanesulfonic acid.

Comparative Examples 1-3
A priming layer 01 is primed on the side to be coated with the emulsion and has a thickness of 175 μm blue-pigmented polyethylene terephthalate having CIELAB a *-and b * -values of -9.5 and -17.9, respectively. Comparative Example 1 was obtained by coating a dispersion having the following components in 2-butanone on a support, and drying in a drying cabinet at 50 ° C. for 1 hour to obtain a layer having the composition shown in Table 1. -3 substantially non-photosensitive thermographic materials were produced.

The thermosensitive element is then coated with an aqueous composition having the following ingredients, adjusted to a pH of 3.8 using 1 N nitric acid, to a wet layer thickness of 85 μm and then dried at 50 ° C. for 15 minutes to give the following composition A protective layer PRO-L was formed having:
ERKOL ^™ 48 20 = 2.1 g / m ²
LEVASIL ^™ VP AC 4055 = 1.05 g / m ²
ULTRAVON ^™ W = 0.075 g / m ²
SYLOID ^™ 72 = 0.09 g / m ²
SERVOXYL ^™ VPDZ 3/100 = 0.075 g / m ²
SERVOXYL ^™ VPAZ 100 = 0.075 g / m ²
MICROACE TALC P3 = 0.045 g / m ²
RILANIT ^™ GMS = 0.15 g / m ²
TMOS = 0.87 g / m ² (assuming TMOS has been completely converted to SiO ₂ )
After coating, the protective layer was hardened by heating the substantially light-insensitive thermographic material at 45 ° C. and 70% relative humidity for 7 days.

Thermographic Printing The substantially light-insensitive thermographic recording materials of Comparative Examples 1 to 3 were printed at a print speed of 14 mm / sec and a line-time of 3.5 ms instead of 7.1 ms. A 75 μm long (in transport direction) and 50 μm wide thermal head resistor is output-modulated to produce various image densities, modified from the AGFA-GEVAERT with a resolution of 508 dpi. Printed using a DRYSTAR ^™ 4500 printer.

Using a MACBETH ^™ TR924 densitometer, the maximum density (D _max ) of the images measured through a visible filter was all higher than 2.2.
Evaluation of thermographic properties The image tones of the new prints made using the substantially light-insensitive thermographic recording materials of Comparative Examples 1 to 3 were evaluated using L *, a at optical densities D of 1.0 and 2.0. The evaluation was based on * and b * CIELAB-values and the results are shown in Table 2.
Archiveability test:
Prints made using the substantially light-insensitive thermographic recording materials of Comparative Examples 1 to 3 were heated in the dark at 34% relative humidity at 57 ° C for 3 days, and CIELAB a *-and b *. Pseudo-long-term archiveability tests were performed by determining shifts in values. The results are also shown in Table 2.
Light-box test:
The substantially light-insensitive thermographic materials of Comparative Examples 1-3 were prepared in a specially assembled light-box white PVC placed in a Votsch conditioning shelf set at 30 ° C. and 85% relative humidity. The light-box test was performed by exposing on a window for three days. Only the central area of the 550 mm long and 500 mm wide window was used to load the test material to assure uniform exposure.

  The stainless steel light-box used was 650 mm long, 600 mm wide and 120 mm high, had an opening 610 mm long and 560 mm wide, and was 10 mm wide and 5 mm deep. The rim is around the opening, thereby forming a platform for a 5 mm thick plate of white PVC of 630 mm in length and 580 mm in width, the white PVC-plate being identical to the top of the light box It is flat and prevents light loss from the light-box except through the white PVC-plate. Nine Planilux? 27 mm in diameter in this light-box? A TLD 36W / 54 fluorescent lamp is mounted equidistant from two sides in the longitudinal direction, the lamps are equidistant from each other and across the entire width of the light-box and the top of the fluorescent tube is from the bottom of the white PVC plate. It was mounted 30 mm below and 35 mm below the material to be tested. The shift in CIELAB a *-and b *-values at an optical density D of 1.0 and the shift in CIELAB b * -values were determined for Comparative Examples 1-3 and the results are also shown in Table 2.

Comparative Examples 4 to 10 and Examples 1 to 14 of the present invention
Coating a dispersion having the following components in 2-butanone on the support described with respect to Comparative Examples 1-3 and drying in a drying cabinet at 85 ° C. for 3 minutes to form a layer having the composition shown in Table 3 This resulted in the production of substantially light-insensitive thermographic materials of Comparative Examples 4-10 and Examples 1-14 of the present invention.

  The heat sensitive element was then provided with a protective layer as described for Comparative Examples 1-3.

As shown in Table 4, has a maximum intensity of about 4700cd / ^{m 2,} the length of 1235Cm, has a depth of width and 10cm of 62cm, Planilux ^TM light surface of 105cmx42cm is used - Box DX 105x43 cm / A light-box test was performed on EHR-AP with Comparative Example 5 and Example 13 of the present invention, and the comparative examples were as described for Comparative Examples 1-3 except that they were exposed for 2 days under ambient conditions. The thermographic properties of the substantially light-insensitive thermographic recording materials of Examples 4 to 10 and Examples 1 to 14 of the present invention were evaluated. Table 4 shows the results.

# Light-box exposures were performed in the PLANILUX ^™ light-box DX under ambient conditions for 2 days.

  The results reported in Table 4 were made using a substantially light-insensitive thermographic recording material having a different composition than the substantially light-insensitive thermographic recording material on which the results reported in Table 2 are based. Was. However, by comparing the results in two tables made with substantially light-insensitive thermographic recording materials having the same stabilizer, the effect of this difference in composition can be estimated. Results for the substantially light-insensitive thermographic recording materials of Comparative Example 1, Comparative Example 4 and Comparative Example 5 using stabilizer S03, benzotriazole and Comparative Example using stabilizer PMT-C2 The results for the substantially light-insensitive thermographic recording materials of Comparative Example 3 and Comparative Example 6 are shown in Table 5.

This comparison shows that the alternative light-box test used for Comparative Example 5 and Inventive Example 13 was for a substantially light-insensitive thermographic recording material containing 10 mol% S03 (benzotriazole). Gave a shift in CIELAB a *-and b *-values comparable to that obtained using the standard light-box test, and the substantially light-insensitive used for Comparative Examples 1-3 The composition of the substantially light-insensitive thermographic recording material used for Comparative Examples 4 to 10 and Examples 1 to 14 of the present invention as compared to the composition of the thermographic recording material of:
A more positive a * -value at D = 1.0 and 2.0;
A more negative b * -value at D = 1.0;
A higher shift in CIELAB values after 3 days / 57 ° C./34% RH in the dark;
And-giving an approximately 2.0 lower shift in CIELAB b * -values after light-box exposure. With this information in mind, the results reported in Tables 2 and 4 can be considered overall.

  In the CIELAB-system, a negative CIELAB a * -value indicates a greenish image-tone, where a * becomes more negative and greener, and a positive a * -value indicates a reddish image-tone. And a * becomes more positive and redder. Negative CIELAB b * -values indicate a bluish tint, b * becomes more negative and more bluish, positive b *-values indicate a yellowish image-hue, and b * is more positive. And become more yellow. In terms of overall image visual perception, the image tones of the elements of the image having a density of 1.0 have a stronger effect than the image tones of the elements having a lower or higher optical density.

In the evaluation of the image tone, the image tone of the SCOpix ^™ LT2B silver halide emulsion laser medical hard copy film from AGFA-GEVAERT was used as a level:

Considering overall the results for the substantially light-insensitive thermographic recording materials containing 1-phenyl-5-mercapto-tetrazoles (PMT's) reported in Tables 2 and 4, the following conclusions are made. Can be withdrawn:
A substantially light-insensitive thermographic recording material containing PMT-C2 showed acceptable stability to light in the light-box test, but showed prohibitively positive CIELAB a * -values;
-All substantially light-insensitive thermographic recording materials containing PMT-C1 and PMT-C3 to PMT-C6 are light as indicated by a high shift in CIELAB b * -values at D = 1.0 and Dmin. -Poor stability to light in the box test; and all substantially light-insensitive thermographic recording materials containing PMT-1 to PMT-13 all have acceptable image shades and acceptable light stability Showed sex.

Examples 15 and 16 of the present invention
A primer layer 02 is primed on the side to be coated with the emulsion and is a 175 μm thick blue-pigmented polyethylene terephthalate having a CIELAB a *-and b * -value of -9.5 and -17.9, respectively. On a support, a dispersion having the following components in 2-butanone was coated and dried in a drying cabinet at 50 ° C. for 1 hour to obtain a layer having the composition shown in Table 6, thereby obtaining S03, benzotriazole. In combination with various 1-phenyl-5-mercapto-tetrazole stabilizers to produce the substantially light-insensitive thermographic materials of Examples 15 and 16 of the present invention used in thermal elements.

  The heat sensitive element was then provided with a protective layer as described for Comparative Examples 1-3.

  The thermographic properties of the substantially light-insensitive thermographic recording materials of Examples 15 and 16 of the present invention were evaluated as described above for Comparative Examples 1-3. Table 7 shows the results.

  The results in Table 7 show that when the 1-phenyl-5-mercapto-tetrazole compound according to the present invention is incorporated into the heat-sensitive element of a substantially light-insensitive thermographic recording material, it is used in combination with S03, a benzotriazole. In some cases, it gives acceptable image tone in the new material as well as acceptable stability in the light-box test.

Examples 17 to 21 of the present invention
A primer layer 02 is primed on the side to be coated with the emulsion and is a 175 μm thick blue-pigmented polyethylene terephthalate having a CIELAB a *-and b * -value of -9.5 and -17.9, respectively. On a support, a dispersion having the following components in 2-butanone was coated and dried in a drying cabinet at 50 ° C. for 1 hour to obtain a layer having the composition shown in Table 8, thereby obtaining S03, benzotriazole. Have been combined with various 1-phenyl-5-mercapto-tetrazole stabilizers to produce the substantially light-insensitive thermographic materials of Examples 17-21 of the present invention used in thermal elements.

  The heat sensitive element was then provided with a protective layer as described for Comparative Examples 1-3.

The thermographic properties of the substantially light-insensitive thermographic recording materials of Examples 17-21 of the present invention were evaluated as described above for Comparative Examples 1-3. Table 9 shows the results.

  The results in Table 9 show that the 1-phenyl-5-mercapto-tetrazole compound according to the present invention was used in combination with S03, a benzotriazole, when introduced into the thermosensitive element of a substantially light-insensitive thermographic recording material. In some cases, it gives acceptable image tone in the new material as well as acceptable stability in the light-box test.

The present invention is directed to any feature or combination of features, either implicitly or explicitly disclosed herein, or whether their generalization relates to the presently claimed invention. Regardless, they can include any of those generalizations. In view of the foregoing description, it will be apparent to one skilled in the art that various modifications may be made within the scope of the present invention.

Claims (3)

A support and a heat-sensitive element, wherein the heat-sensitive element is substituted by a substantially light-insensitive organic silver salt, an organic reducing agent therefor in a thermal working relationship therewith, a binder and a phenyl group. A 1-phenyl-5-mercaptotetrazole compound substituted with a substituent containing an aryl group that can be used; and

A substantially light-insensitive black-and-white monosheet thermographic recording material containing at least one stabilizer selected from the group consisting of: The substituent -NHCO- phenyl, -NHCO- (1-naphthyl), for the phenyl group - NHCO- (2-naphthyl), - -NHCONH- phenyl, -NHSO ₂ - phenyl, -NHSO ₂ - (1 - naphthyl), - NHSO ₂ - (2- naphthyl), _- SO 2 NH- phenyl, -CONH- phenyl, -CONH- (1-naphthyl), - CONH- (2-naphthyl), - NHCO- (2- A substantially light-insensitive black-and-white monosheet thermographic recording material according to claim 1, selected from the group consisting of thienyl) and -NHCONHCO-phenyl groups. The optional substituent for the aryl group is a halogen atom, an ester group, an -OCOO-alkyl group, a -NHCOO-alkyl group, a -NHOC-alkyl group, a -CONH-alkyl group, a -S-alkyl group and a mercapto; 3. A substantially light-insensitive black-and-white monosheet thermographic recording material according to claim 1 or 2, selected from the group consisting of alkyl, alkoxy, nitrile, acyl and nitro groups.