JP2004161006A - 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 stabilizer is a substantially photosensitive black and white monochrome sheet thermographic recording material consisting of a support and thermosensitive elements, which includes a substantially non-photosensitive organic silver salt, an organic reducing agent for the silver salt put under a thermal action relationship therewith, a binder and at least one kind of 2-mercapto-benzothiazole compound. <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. M is 0 or 1; n is an integer from 1 to 3]
A thermally developable photosensitive material containing a compound represented by (immobilizing group) is disclosed. Patent Document 1 discloses the following 2-mercapto-benzothiazole compound:

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 comprises (1):
Formula (1) X ₁ -L ₁ -A
[In the formula, 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 group thereof. Selected from the group consisting of salts, sulfo groups or salts thereof, and sulfine groups or salts thereof]
And a compound represented by the general formula (2):
Equation ₍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.
Discloses a thermally developable photosensitive material comprising a compound represented by Patent Document 2 discloses the following 2-mercapto-benzothiazole compound:

  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 further discloses that, in the above method, the first photosensitive sheet material further has the following formula III or IV:

[Wherein Q represents a group necessary for completing a heterocyclic group containing a 5- or 6-membered heterocyclic ring, and X represents a carboxylic acid or sulfonic acid group or a carboxylic acid or sulfonic acid group. Indicates the contained residue];
as well as

Wherein R ⁴ represents hydrogen, alkyl, alkoxy or halogen having up to 18 carbon atoms, R ⁵ represents hydrogen or an alkyl group having up to 18 carbon atoms, R ⁶ represents hydrogen or 3 And n represents 0, 1 or 2].
Are disclosed that contain at least one compound corresponding to one of the following: Patent Document 3 describes an effective compound

Are also disclosed.

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. U.S. Pat. No. 6,059,067 discloses on page 15 the following 2-mercapto-benzothiazole compound under No. 24:

  US Pat. No. 5,077,086 discloses a photothermographic material comprising a binder, an organic silver salt, a reducing agent for silver ions and photosensitive silver halide grains on at least one surface of a support, wherein the photosensitive thermosensitive material comprises The photosensitive layer containing silver halide grains further contains a compound of formula (I) and a compound of formula (II), and the photosensitive layer has an absorbance of 9 at an exposure wavelength of 0.15 to 1.0. .

RS (M) _n (I)
Where R is an aliphatic hydrocarbon, aryl or heterocyclic group, M is a hydrogen atom or a cation, and the letter n is a number determined to make the molecule neutral.

In the formula, Z ₁ is an atomic group necessary for forming a 5- or 6-membered nitrogenous heterocyclic ring, and each of D and D ′ is an atomic group necessary for forming an acyclic or cyclic acidic nucleus; ₁ is an alkyl group; L _1, L ₂ , L ₃ , L ₃ , L ₄ , L ₅ , L ₆ , L ₇ , L ₈ , L _9, and L ₁₀ are each a methine group; may form a ring together with the ring having a methine group or an auxochrome, characters n1, n2, n3, n4 and n5 are each equal to 0 or 1, _{M 1} is a counter ion for neutralizing charge, m1 Is an integer, including 0, necessary to neutralize the charge on the molecule. Patent document 5 further discloses the following 2-mercapto-benzothiazole compounds as being compounds included in formula (I):

  U.S. Pat. Nos. 5,059,086, 5,069,086, 5,045, and 4,069,064 disclose the use of various 2-mercapto-benzothiazole compounds in photothermographic recording materials. 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, which in the case of thermographic recording materials is a similarity on the outer surface that masks the image-wise heating of a heat-sensitive element containing no 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 differences between the light-sensitive silver halide and the spectral sensitizer in substantially light-insensitive thermographic recording materials. Absence, but also reflected in the different reducing agents used, is used in substantially light-insensitive thermographic recording materials, and is reflected 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. 6,077,086 discloses a donor element comprising a support layer containing a (i) a binder and a thermally transferable reducing agent capable of reducing a silver source to metallic silver on a support; and (ii) a thermal element 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.

US Pat. No. 5,077,059 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 Discloses a substantially non-photosensitive monosheet recording material characterized by the energy in joules applied in the dot area of the image forming layer material. U.S. Pat. No. 6,047,086 discloses the following 2-mercapto-benzothiazole compounds:

  US Pat. No. 5,077,086 discloses a color-forming amount of a 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; 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. In addition, US Pat. No. 6,059,086 discloses that suitable antifoggants are mercaptobenzotriazole, chromate, oxalate, citrate, carbonate, benzotriazole (BZT), 5-methylbenzotriazole, 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 6 published on May 22, 1996
Patent document 4 published on April 29, 1998
Patent document 7 published on March 10, 1999
Patent document 5 issued on July 13, 1999
Patent document 8 published on July 21, 1994
Patent document 9 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 U.S. Pat. No. 5,922,529 European Patent Application Publication No. 07131133 European Patent Application Publication No. 0901040 International Publication No. 94/16361 pamphlet WO 96/10213 pamphlet

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 2-mercapto-benzothiazole compounds provide CIELAB a * and b * in substantially light-insensitive thermographic recording materials suitable for use in high-throughput thermographic printers. It has been found to provide effective stabilization without adversely affecting the image tone characterized by the value. 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 is a substantially light-insensitive organic silver salt, an organic reducing agent therefor in a thermal working relationship therewith, a binder and a compound of formula (I) ):

[Wherein, R ¹ , R ² , R ³ and R ⁴ are independently hydrogen, an optionally substituted alkyl group, an optionally substituted aryl group, an alkoxy group, an ester group , A carbamate group, a carbonato group, a SO ₂ R ⁵ group, a —NR ⁶ R ⁷ group, a nitro group, a cyano group, an acyl group, a halogen atom, and optionally an alkyl or alkoxy-substituted —SO ₂ NH— A phenyl group, a perfluoro-alkyl group, a —CONHR ⁸ , a —NHOCR ⁹ , a —OCOOR ^10, or a —NHCOOR ¹¹ group; R ⁵ , R ⁹ , R ¹⁰ and R ¹¹ are independently optionally substituted R ⁶ , R ⁷ and R ⁸ are independently a hydrogen atom, optionally substituted R ¹ and R ² together, R ² and R ³ together, and R ³ and R ⁴ together, independently of carbon The atoms necessary to form a cyclic, aromatic, heteroaromatic or heterocyclic ring may be indicated, provided that at least one of R ¹ , R ² , R ³ and R ⁴ is not hydrogen.
This is realized using a substantially light-insensitive black-and-white monosheet thermographic recording material containing at least one 2-mercapto-benzothiazole compound represented by

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 system in approximately equilibrium with water in air, wherein water for inducing or promoting the reaction is an element of water. No special or positive supply from outside. 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.

2-Mercapto-benzothiazole compound The substantially light-insensitive black-and-white monosheet thermographic recording material of the present invention has the formula (I):

[Wherein, R ¹ , R ² , R ³ and R ⁴ are independently hydrogen, an optionally substituted alkyl group, an optionally substituted aryl group, an alkoxy group, an ester group , A carbamate group, a carbonato group, a SO ₂ R ⁵ group, a —NR ⁶ R ⁷ group, a nitro group, a cyano group, an acyl group, a halogen atom, and optionally an alkyl or alkoxy-substituted —SO ₂ NH— A phenyl group, a perfluoro-alkyl group, a —CONHR ⁸ , a —NHOCR ⁹ , a —OCOOR ^10, or a —NHCOOR ¹¹ group; R ⁵ , R ⁹ , R ¹⁰ and R ¹¹ are independently optionally substituted R ⁶ , R ⁷ and R ⁸ are independently a hydrogen atom, optionally substituted R ¹ and R ² together, R ² and R ³ together, and R ³ and R ⁴ together, independently of carbon The atoms necessary to form a cyclic, aromatic, heteroaromatic or heterocyclic ring may be indicated, provided that at least one of R ¹ , R ² , R ³ and R ⁴ is not hydrogen.
At least one 2-mercapto-benzothiazole compound represented by the following formula: Preferred optional substituents for the optionally substituted alkyl and aryl groups are halogen atoms, groups containing a 2-mercapto-benzothiazole moiety and alkyl, alkoxy, mercapto and hydroxy groups.

  According to a first embodiment of the substantially light-insensitive black-and-white monosheet thermographic recording material of the present invention, the at least one benzothiazole compound according to formula (I) comprises an alkyl, aryl, alkoxy, nitro, cyano or acyl group. Alternatively, it is a 2-mercapto-benzothiazole compound substituted by a halogen atom.

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

It is.

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

It is.

  The 2-mercapto-benzothiazole compounds of the formula (I) according to the present invention are known to the person skilled in the art from readily available starting materials and available in references such as Houben-Weyl. It can be prepared using any standard organic chemistry method.

  Suitable 2-mercapto-benzothiazole (MBT) compounds according to the present invention 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.

  Combinations of reducing agents that become the reactive partner in the reduction of one or more substantially light-insensitive organic silver salts when heated can also be used. 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 which can be used, preferably Polyvinyl 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 invention, the heat-sensitive element further comprises at least one polycarboxylic acid and / or its anhydride, Contains at least 15 mole percentages relative to all organic silver salts of the species 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

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 and 2 and Examples 1 and 2 of the present invention
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. And 2 and the substantially light-insensitive thermographic materials of Examples 1 and 2 of the present invention.

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 and 2 and Examples 1 and 2 of the present invention were printed at a print speed of 14 mm / sec and 3.5 ms instead of 7.1 ms. A 508 dpi thermal head resistor that is modified to operate with a line-time of 75 μm long (in the transport direction) and 50 μm wide is output-modulated to produce various image densities. Printed using a DRYSTAR ^™ 4500 printer from AGFA-GEVAERT with a resolution of.

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 Image tones of new prints made using the substantially light-insensitive thermographic recording materials of Comparative Examples 1 and 2 and Examples 1 and 2 of the present invention were 1.0 and 2.0. Were evaluated based on the L *, a * and b * CIELAB-values at an optical density D of
Archiveability test:
Prints made using the substantially light-insensitive thermographic recording materials of Comparative Examples 1 and 2 and Examples 1 and 2 of the present invention were heated for 3 days at 57 ° C. in the dark at 34% relative humidity. A pseudo long-term archive test was then performed by determining the shift in CIELAB a *-and b *-values. The results are also shown in Table 2.
Light-box test:
The substantially light-insensitive thermographic materials of Comparative Examples 1 and 2 and Examples 1 and 2 of the present invention were specially placed in a Votsch conditioning shelf set at 30 ° C. and 85% relative humidity. The light-box test was performed by exposing the assembled light-box on a white PVC 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 and 2 and Examples 1 and 2 of the present invention and the results were again It is shown in Table 2.

  In the light-box test, the substantially light-insensitive thermographic recording materials of Examples 1 and 2 of the invention containing MBT-1 and MBT-2, respectively, of the compounds according to the invention have an optical density D of 1.0. The CIELAB b * -value and the CIELAB b * -value at Dmin show a substantially smaller shift than that of Comparative Example 2 containing compound MBT-C1. Thus, the substituted 2-mercapto-benzothiazoles MBT-1 and MBT-2 provide a substantially light-insensitive thermographic recording material having substantially higher photostability than the unsubstituted 2-mercapto-benzothiazole, MBT-C1. give.

Comparative Examples 3 and 4
On a support as described for Comparative Examples 1 and 2 and Examples 1 and 2 of the present invention, a dispersion having the following components in 2-butanone was coated and dried in a drying cabinet at 85 ° C. for 3 minutes. The substantially light-insensitive thermographic materials of Comparative Examples 3 and 4 were made by later obtaining layers having the compositions shown in Table 3.

  The heat-sensitive element was then provided with a protective layer as described for Comparative Examples 1 and 2 and Examples 1 and 2 of the present invention.

  The thermographic properties of the substantially light-insensitive thermographic recording materials of Comparative Examples 3 and 4 were evaluated as described with respect to Comparative Examples 1 and 2 and Examples 1 and 2 of the present invention. Table 4 shows the results.

  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. The results for the substantially light-insensitive thermographic recording materials of Comparative Example 1, Comparative Example 3 and Comparative Example 4 using stabilizer S03 and benzotriazole are shown in Table 5.

This comparison was made for Comparative Examples 3 and 4 as compared to the composition of the substantially light-insensitive thermographic recording material used for Comparative Examples 1 and 2 and Examples 1 and 2 of the present invention. The composition of the substantially light-insensitive thermographic recording material used is:
A more negative b * -value at D = 1.0;
Giving a higher shift in CIELAB b * -values after 3 days / 57 ° C./34% RH in the dark; and about 2.0 lower shifts in CIELAB b * -values after light-box exposure. It is shown that. With this information in mind, the results reported in Tables 2 and 4 can be considered overall.

  In the CIELAB-system, a negative CIELAB b * -value indicates a bluish tint, with b * becoming more negative and increasingly bluer, a positive b * -value indicates a yellowish image-hue. , B * become more positive and 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 2-mercapto-benzothiazoles (MBT's) reported in Tables 2 and 4, the following conclusions can be drawn. Can:
• The substantially light-insensitive thermographic recording material of Comparative Example 2 containing MBT-C1 has a light-box test as indicated by a high shift in CIELAB b * -values at D = 1.0 and Dmin. Showed poor stability to light;
-The substantially light-insensitive thermographic recording material of Comparative Example 4 containing MBT-C2 was inferior in the archiveability box test as indicated by a high shift in CIELAB b * -value at D = 1.0. And the substantially light-insensitive thermographic recording materials of Examples 1 and 2 of the present invention containing MBT-1 and MBT-2 exhibited acceptable image tones. Demonstrated an acceptable archival stability and much improved light stability as compared to the substantially light insensitive thermographic recording material of Comparative Example 4 containing MBT-C1.

Comparative Examples 5 to 7 and Examples 3 to 11 of the present invention
After coating the dispersions having the following components in 2-butanone on the support described in relation to Comparative Examples 1 and 2 and Examples 1 and 2 of the invention and drying in a drying cabinet at 85 ° C. for 3 minutes, The substantially light-insensitive thermographic materials of Comparative Examples 5 to 7 and Examples 3 to 11 of the present invention were produced by obtaining layers having the compositions shown in Table 6.

  The heat-sensitive element was then provided with a protective layer as described for Comparative Examples 1 and 2 and Examples 1 and 2 of the present invention.

  The thermographic properties of the substantially light-insensitive thermographic recording materials of Comparative Examples 5 to 7 and Examples 3 to 11 of the present invention as described with respect to Comparative Examples 1 and 2 and Examples 1 and 2 of the present invention. Was evaluated. Table 7 shows the results.

  The substantially light-insensitive recording materials of Examples 3 to 11 of the present invention containing the stabilizers MBT-3 to MBT-11 have improved lightbox stability, i.e., of Comparative Example 7 without the stabilizer. Shift in CIELAB b * -value for Dmin reduced compared to substantially light-insensitive recording material and equivalent compared to substantially light-insensitive recording material of Comparative Example 8 using benzotriazole Or a shift in CIELAB b * -value for reduced Dmin.

  The present invention is independent of any feature or combination of features implicitly or explicitly disclosed herein, or whether its generalization relates to the presently claimed invention. Can include any of its 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 a substantially light-insensitive organic silver salt, an organic reducing agent therefor in a thermal working relationship therewith, a binder and a compound of formula (I):

[Wherein, R ¹ , R ² , R ³ and R ⁴ are independently hydrogen, an optionally substituted alkyl group, an optionally substituted aryl group, an alkoxy group, an ester group , A carbamate group, a carbonato group, a SO ₂ R ⁵ group, a —NR ⁶ R ⁷ group, a nitro group, a cyano group, an acyl group, a halogen atom, and optionally an alkyl or alkoxy-substituted —SO ₂ NH— A phenyl group, a perfluoro-alkyl group, a —CONHR ⁸ , a —NHOCR ⁹ , a —OCOOR ^10, or a —NHCOOR ¹¹ group; R ⁵ , R ⁹ , R ¹⁰ and R ¹¹ are independently optionally substituted R ⁶ , R ⁷ and R ⁸ are independently a hydrogen atom, optionally substituted R ¹ and R ² together, R ² and R ³ together, and R ³ and R ⁴ together, independently of carbon The atoms necessary to form a cyclic, aromatic, heteroaromatic or heterocyclic ring may be indicated, provided that at least one of R ¹ , R ² , R ³ and R ⁴ is not hydrogen.
A substantially light-insensitive black-and-white monosheet thermographic recording material containing at least one 2-mercapto-benzothiazole compound represented by   2. The method according to claim 1, wherein the at least one 2-mercapto-benzothiazole compound according to the formula (I) is a 2-mercapto-benzothiazole compound substituted by an alkyl, aryl, alkoxy, nitro, cyano or acyl group or a halogen atom. A substantially light-insensitive black-and-white monosheet thermographic recording material.   3. A substantially non-light-sensitive black-and-white monosheet thermographic recording material according to any of claims 1 and 2, wherein the thermosensitive element further comprises an optionally substituted benzotriazole.