JP2000158819A - Substantially light-insensitive black and white thermographic recording material of improved stability to direct sunlight - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a substantially light-insensitive black and white monosheet thermographic recording material of improved stability to direct rays of the sun basing on an organic silver salt and a reducing agent capable of forming an image of allowable neutral image tone. SOLUTION: A substantially light-insensitive black and white monosheet thermographic recording material containing non-chlorine containing stabilizer comprises a support and a thermosensitive element, and the thermosensitive element contain a substantially light-insensitive organic silver salt, a reducing agent therefor in thermal working relation ship therewith and a binder, and the non-chlorine containing stabilizer is selected from the group consisting of a 2-(2'-hydroxyphenl)benzotriazole derivatives and a 2-hydroxy-benzophenone derivatives, and a thermographic recording method therewith and the use thereof as a stabilizer for the direct sunlight are also provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

FIELD OF THE INVENTION The present invention relates to a substantially non-photosensitive black-and-white mainsheet (ma) having improved stability to direct sunlight.
inseat) thermographic recording material.

[0002]

BACKGROUND OF THE INVENTION Thermal imaging or thermography is a recording method in which an image is formed by the use of thermal energy.
In direct thermal thermography, a visible image pattern is formed by image-wise heating of a recording material containing a substance that changes color or optical density by a chemical or physical process. Most of the "direct" thermographic recording materials are of the chemical type. When heated to a certain conversion temperature, an irreversible chemical reaction occurs and a colored image is formed.

[0003] BE-A 784,615 comprises a paper support on which from 5 to about 100 Sheffield.
d. a layer having a smoothness (smoothness) is coated, said layer comprising a polysaccharide-type first binder, a pigment, a second binder, a photosensitive compound including 2,4-dihydroxybenzophenone, and an oxidizing agent. A photographic material comprising a reduced image forming system is disclosed.

EP-A 713 133 discloses a donor element comprising on a support a donor layer comprising (i) a binder and a thermally conductive reducing agent capable of reducing a silver source to metallic silver; A silver source, binder and benzotriazole, heterocyclic mercaptan, sulfinic acid, 1,3,4-triazo-indinoline, 1,3-dinitroaryl compound, 1,
Disclosed is a two-sheet thermal imaging system comprising a receiving element comprising on a support a receiving layer comprising a stabilizer selected from the group consisting of 2,3-triazole, phthalic acid and phthalic acid derivatives.

EP-A 809 142 comprises a support, a heat-sensitive element and a protective layer therefor, wherein the heat-sensitive element is a substantially non-photosensitive organic silver salt, and an organic silver salt therefor in a thermal working relationship therewith. A reducing element and a binder, wherein the thermosensitive element is further cycloadded with an aromatic ring system, consisting of nitrogen and carbon atoms, wherein at least one of the nitrogen atoms has a hydrogen atom, and Having an unsaturated 5-membered heterocyclic ring which is not directly bonded to a sulfur atom or which is not part of a carbonyl group, and which is substituted or unsubstituted by a group having only an electron-withdrawing property A recording material comprising a compound in a reactive relationship with a substantially non-photosensitive organic silver salt and an organic reducing agent is disclosed.

[0006] Substantially non-compliant according to EP 713 133
The photosensitive black-and-white two-sheet thermographic recording material forms an image on the receiving sheet with an image-wise transferred reducing agent, thus creating totally different stability conditions than the mono-sheet material. Non-N as described in EP-A 809142
Substantially non-light sensitive black-and-white monosheet thermographic recording materials containing substituted benzotriazoles exhibit poor stability to direct sunlight.

[0007]

OBJECTS OF THE INVENTION Accordingly, it is an object of the present invention to provide an organic silver salt and reduced organic silver salt having improved stability against direct sunlight and capable of forming an image having an acceptable neutral image tone. It is to provide a substantially non-photosensitive black-and-white monosheet thermographic recording material based on the agent.

[0008] Further objects and advantages of the invention will become apparent from the description hereinafter.

[0009]

SUMMARY OF THE INVENTION Surprisingly, substantially non-photosensitive black-and-white monosheet thermographic recording materials based on organic silver salts and reducing agents are provided with non-chlorine-containing 2- (2'-hydroxyphenyl) benzotriazole derivatives. And the incorporation of 2-hydroxy-benzophenone derivatives have been found to produce materials whose prints exhibit improved stability to direct sunlight and acceptable neutral image tones.

The above object comprises a support and a thermosensitive element, wherein the thermosensitive element is a substantially non-photosensitive organic silver salt;
A non-chlorine-containing stabilizer is selected from the group consisting of 2- (2'-hydroxyphenyl) benzotriazole derivatives and 2-hydroxy-benzophenone derivatives, including a reducing agent and a binder therefor in thermal action therewith. This is achieved by a substantially non-photosensitive black-and-white non-chlorine-containing stabilizer-containing mono-sheet thermographic recording material.

According to the present invention, further, (i) bringing the outermost layer of the thermographic recording material into close proximity to a heat source;
i) applying an image-wise heat from the heat source to the recording material while in proximity to the heat source to form an image; and (iii) removing the recording material from the heat source.

According to the present invention, it also comprises a support and a heat-sensitive element, wherein said heat-sensitive element is a substantially non-photosensitive organic silver salt, a reducing agent therefor in thermal working relationship therewith and a bond. From the group consisting of 2- (2'-hydroxyphenyl) -benzotriazole derivatives and 2-hydroxy-benzophenone derivatives as stabilizers against direct sunlight in substantially non-photosensitive black-and-white monosheet thermographic recording materials containing the agent Use of a selected non-chlorine containing stabilizer is provided.

[0013] Preferred embodiments of the invention are disclosed in the dependent claims.

[0014]

DETAILED DESCRIPTION OF THE INVENTION In a preferred embodiment of the recording method according to the invention, the heat source is a thermal head, with a thin film thermal head being particularly preferred.

Definitions Substantially non-photosensitive is furthermore defined as intententi.
only) not photosensitive.

The non-chlorine-containing compound means a compound having no chlorine atom in its structure.

The polymer having an active hydrogen atom means a polymer having a hydrogen atom which easily reacts, for example, a hydroxy group, a thiol group, a carboxy group, a -NH group, an amino group, an amide group and the like. I do.

By polyisocyanate is meant a compound having at least two isocyanate groups, the isocyanate groups being able to be blocked or unblocked by groups which are easily replaced during the hardening process. I do.

2- (2'-Hydroxyphenyl) benzotriazole derivative and 2-hydroxybenzophenone derivative Preferred non-chlorine-containing 2- (2'-hydroxyphenyl) -benzotriazole derivatives are benzotriazole and / or benzene benzene. Substituents on the ring are, for example, alkyl groups such as methyl, t-butyl, t-amyl, t-octyl, etc., aryl, alkaryl, aralkyl such as benzyl, α, α-dimethylbenzyl, alkoxy, alkcarboxy. It has a latet group and the like. These groups can be further substituted with hydroxy, alkyl, alkaryl, aralkyl, aryl, alkoxy, alkcarboxylate, 2-benzotriazolo groups and the like. Non-chlorine-containing 2- () suitable for use in the substantially non-photosensitive black-and-white stabilizer-containing monosheet thermographic recording materials of the present invention without adversely altering the neutrality of the image tone of the image background. The 2′-hydroxyphenyl) -benzotriazole derivatives are as follows: STAB 01: 2- (2′-hydroxy-5-methylphenyl) benzotriazole, CIBA-GEIG
TINUVIN ^™ P from Y; STAB 02: 2- (2′-hydroxy-5′-t
-Octylphenyl) benzotriazole, Ameri
can Cyanamid Co. CYASOR from
^{B TM UV 5411; · STAB 03} : 2- [2'- hydroxy-3 ',
5 '-(Di-t-butyl) phenyl] -benzotriazole, TINUVIN ^™ from CIBA-GEIGY
320:

[0020]

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SATB 04: 2- [2'-hydroxy-3 ', 5'-(di-t-amyl) phenyl] benzo-triazole, TINU from CIBA-GEIGY
VIN ^™ 328:

[0022]

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SATB 05: 2- [2'-hydroxy-3 ', 5'-di- (α, α-dimethylbenzyl) phenyl] benzotriazole, TINUVIN ^™ 900 from CIBA-GEIGY:

[0024]

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STAB 06: 2- [2'-hydroxy-5- (1 ", 1", 3 ", 3" -tetramethylbutyl) -phenyl] -benzotriazole; STAB 07: 2,2-methylene -Bis- [5-
(2H-benzotriazol-1-yl) -3-
(1 ", 1", 3 ", 3" -tetramethylbutyl) -phenol]:

[0026]

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STAB 08: 2- {3'-t-butyl-2'-hydroxy-5 '-[2-ethyl- (methyl polyethylene oxide) -ketono] -phenyl} -benzotriazole

[0028]

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STAB 09: CIBA-GEIGY
TINUVIN ^™ 213 from:

[0030]

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STAB 10: 2- {3'-t-butyl-2'-hydroxy-5-3- (octylpropionate) -phenyl} -benzotriazole, CIBA-
TINUVIN ^™ 384 from GEIGY:

[0032]

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STAB 11:

[0034]

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Is as follows.

Preferred non-chlorine-containing 2-hydroxy-benzophenone derivatives include substituents on one or both benzene rings, such as alkyl, aryl, alkaryl, aralkyl, hydroxy, alkoxy, alkcarboxylate groups. Etc. Without adversely altering the neutrality of the image tone of the image background, the substantially non-
Non-chlorine-containing 2-hydroxy-benzophenone derivatives suitable for use in the photosensitive black-and-white stabilizer-containing monosheet thermographic recording material are as follows: STAB 12: 2,4-dihydroxybenzophenone; STAB 13 : 2-hydroxy-4-methoxybenzophenone;

[0037]

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STAB 14: 2-hydroxy-4-
STAB 15: 2-hydroxy-4-isooctyloxybenzophenone; STAB 16: 2-hydroxy-4-dodecyloxybenzophenone; STAB 17: 2,2'-dihydroxy-4-methoxybenzophenone STAB 18: 2,2 ', 4,4'-tetrahydroxybenzophenone; STAB 19: 2,2'-dihydroxy-4,4'
-Dimethoxybenzophenone.

In a preferred embodiment of the thermographic recording material according to the invention, the non-chlorine-containing 2- (2'-hydroxyphenyl) benzotriazole derivative contains a 2-hydroxybenzophenone group. In another preferred embodiment of the present invention, the non-chlorine-containing 2-
The (2′-hydroxyphenyl) -benzotriazole derivative is 2- [2′-hydroxy-3 ′, 5 ′-(di-
t-butyl) phenyl] -benzotriazole, 2-
[2′-hydroxy-3 ′, 5′-di- (α, α-dimethylbenzyl) phenyl] -benzotriazole, 2,
2-methylene-bis- [5- (2H-benzotriazol-1-yl) -3- (1 ", 1", 3 ", 3" -tetramethylbutyl) -phenol], 2,2-methylene-
Bis- [5- (2H-benzotriazol-1-yl)
-3- (1 ", 1", 3 ", 3" -tetramethylbutyl) -phenol],

[0040]

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Selected from the group consisting of:

A mixture of one or more 2- (2'-hydroxyphenyl) benzotriazole derivatives; a mixture of one or more 2-hydroxy-benzophenone derivatives; or one or more 2- (2 Mixtures of '-hydroxyphenyl) benzotriazole derivatives and one or more 2-hydroxy-benzophenone derivatives can be used in the thermographic recording materials of the present invention.

Thermal element The thermal element according to the present invention comprises a substantially non-photosensitive organic silver salt, a reducing agent therefor in a thermal working relationship therewith and a binder. The element can comprise a layer system in which the components can be dispersed in various layers, provided that the substantially non-photosensitive organic silver salt is in reactive association with the reducing agent, i.e. During the typical development process, the reducing agent must be present in such a way that it can diffuse into the particles of the substantially non-photosensitive organic silver salt and that silver reduction can take place. In a preferred embodiment, the thermosensitive element further contains a polymer having active hydrogen atoms, at least a portion of which has been reacted with the polyisocyanate.

Organic Silver Salt The preferred substantially non-photosensitive organic silver salt for use in the heat-sensitive element of the substantially non-photosensitive black-and-white thermographic recording material used in the present invention has preferably an aliphatic carbon chain. Is a silver salt of an aliphatic carboxylic acid known as a fatty acid having at least 12 C-atoms, which silver salt is also called "silver soap". Various combinations of organic silver salts can be used in the image forming material of the present invention.

Reducing agents Suitable organic reducing agents for the reduction of substantially non-photosensitive organic silver salts are: catechol; hydroquinone; aminophenol;
METOL ^™ ; p-phenylenediamine; alkoxynaphthols such as 4-methoxy-1-naphthol described in US Pat. No. 3,094,417; pyrrolidin-3-one type reducing agents such as PHENIDONE ^™ ; pyrazoline-5 On; indane-1,3-dione derivatives; hydroxytetronic acid; hydroxytetronimide; hydroxylamine derivatives, for example as described in US Pat. No. 4,082,901; hydrazine derivatives; and reductones, for example ascorbin Organic compounds containing at least one active hydrogen atom bonded to O, N or C as in the case of acids, US-P 3,074,809;
3,080,254, 3,094,417 and 3,88
See also 7,378.

The choice of the reducing agent affects the heat sensitivity of the image forming material and the gradation of the image. For example, gallate (galla
The image forming material using (tes) has a high gradation. In a preferred embodiment of the invention, the thermographic element is a 3,4-dihydroxyphenyl compound, for example,
Ethyl 3,4-dihydroxybenzoate, butyl 3,4-dihydroxybenzoate and 3,4-dihydroxybenzoic acid, and formula (I):

[0047]

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Wherein n is 0 or 1; R is-(C
^{= O) R 1, - (} C = O) NR 1 R 2, -CN, -SO 3 R
_{^{1, -SO 2 R 1, -SOR}} 1, -SO 2 NR 1 R 2 or -P
O ₃ be R ¹ R ^2; R ¹ is H or alkyl, substituted alkyl, aryl or substituted aryl group; R ² is H
Or an alkyl, substituted alkyl, aryl or substituted aryl group; R ¹ and R ² together can represent an atom for ring closure, which may be a carbocyclic ring wherein all ring atoms are carbon atoms, or The ring atoms can be heterocyclic rings wherein the ring atoms are carbon and at least one non-carbon atom, for example, nitrogen, sulfur, oxygen, phosphorus and the like. Alkyl and aryl groups can also be substituted with one or more groups selected from hydroxy, cyano, thiol and halogen. Particularly preferred-(CH = CH) _n R groups are formyl, oxo-alkyl, oxo-aryl, cyano, carbamide, diphenoxyphosphoryl, alkylsulfinyl, alkylsulfonyl and sulfonylamino groups.

It is also possible to use a combination of reducing agents which upon heating becomes a reactive partner in the reduction of substantially non-photosensitive organic silver salts.

Toner To obtain a neutral black image tone at higher densities and a neutral gray at lower densities, the heat-sensitive element preferably further comprises a so-called toner known from thermography or photothermography. contains.

Suitable toning agents are phthalimide and US
-P Phthalazinone in the range of the general formula described in 4,082,901. Further, US-P 3,0
74,809, US-P 3,446,648 and US
-P 3,844,797. Other particularly useful toning agents are GB-P 1,4
39,478, US-P 3,951,660 and US
-P 5,599,647 is a benzoxazinedione or naphthooxazinedione type heterocyclic toner compound.

Binders The film-forming binders of the thermosensitive element containing mixed crystals of two or more organic silver salts are all capable of uniformly dispersing the organic silver salts in an aqueous or solvent medium. Natural, modified natural or synthetic resins of the type or mixtures of such resins; for example cellulose derivatives, such as ethyl cellulose, cellulose esters, such as cellulose nitrate, carboxymethyl cellulose, starch ether, galactomannan, α, β-ethylenically unsaturated. Polymers derived from compounds such as polyvinyl chloride, post-chlorinated polyvinyl chloride, copolymers of vinyl chloride and vinylidene chloride, copolymers of vinyl chloride and vinyl acetate,
Polyvinyl acetal, preferably polyvinyl butyral, which is made from polyvinyl acetate and partially hydrolyzed polyvinyl acetate, polyvinyl alcohol, polyvinyl alcohol, and in which only a part of the vinyl alcohol units can be repeatedly reacted with the aldehyde, It can be a copolymer of acrylonitrile and acrylamide, polyacrylate, polymethacrylate, polystyrene, and polyethylene or mixtures thereof.

Water-soluble film-forming binders suitable for use in the thermographic recording materials of the present invention include: polyvinyl alcohol, polyacrylamide, polymethacrylamide, polyacrylic acid, polymethacrylic acid, polyvinylpyrrolidone, polyethylene glycol, protein Sex binders such as gelatin, modified gelatin such as phthaloyl gelatin, polysaccharides such as starch, acacia and dextran, and water-soluble cellulose derivatives.
A preferred water-soluble binder for use in the thermographic recording material of the present invention is gelatin.

Preferred waters for use in accordance with the present invention
The dispersible binder is a water-dispersible film having a covalently bonded ionic group selected from the group consisting of sulfonate, sulfinate, carboxylate, phosphate, quaternary ammonium, tertiary sulfonium and quaternary phosphonium groups. It is a forming polymer. Yet another preferred water-dispersible binder for use in accordance with the present invention is
Water-dispersible film-forming polymers having covalently bonded moieties with one or more acid groups. Preference is also given to water-dispersible binders having crosslinkable groups, such as epoxy groups, aceto-acetoxy groups and crosslinkable double bonds. A particularly preferred water-dispersible binder for use in the thermographic recording materials of the present invention is a polymer latex.

The weight ratio of binder to organic silver salt is preferably in the range from 0.2 to 6, and the thickness of the heat-sensitive element is preferably in the range from 5 to 50 μm.

Still Other Stabilizers and Antifoggants To further extend shelf life and reduce fog, further stabilizers and antifoggants may be used in the substantially non-photosensitive black and white thermography used in the present invention. It can be introduced into the recording material. Suitable stabilizer compounds for use in the present invention are unsaturated carbocyclic or heterocyclic compounds substituted with a -SA group, wherein A is hydrogen, a pair for compensating for the negative charge of the thiolate group. A group that forms an ion or a symmetric or asymmetric disulfide.

Surfactants and Dispersants Surfactants and dispersants aid in dispersing components that are insoluble in a particular dispersion medium. The substantially non-photosensitive black-and-white thermographic recording material used in the present invention comprises one or more surfactants and / or one or more surfactants, which can be anionic, non-ionic or cationic surfactants. Species or more 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.

Other Ingredients In addition to the ingredients, the substantially non-photosensitive black and white thermographic recording material comprises other additives, such as free fatty acids, antistatic agents, such as F ₃ C (CF ₂ ) ₆ CONH ( CH ₂ CH ₂ O)
It may contain a non-ionic antistatic agent containing a fluorocarbon group as in -H, silicone oil and silica.

The support of the substantially non-photosensitive black and white thermographic recording material used in the present invention can be transparent or translucent, and is preferably made from a transparent resin film.
For example, a thin flexible carrier made of a cellulose ester such as cellulose triacetate, a polyester such as polypropylene, polycarbonate or 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 thermal element coated thereon. The support can be dyed or pigmented to give a transparent colored background for the image.

Protective Layer The protective layer protects the heat sensitive element from surface damage due to atmospheric humidity and scratching, etc., and prevents direct contact of the printhead or heat source with the recording layer. The recording layer must be in contact with the heat source under pressure and transported through it, exhibit resistance to local deformation, and have excellent sliding properties during transport through the heat source during heating. There must be.

[0062] Solid or liquid lubricants or combinations thereof are suitable for improving the sliding properties of the thermographic recording materials of the present invention. Solid lubricants that can be used according to the present invention are polyolefin waxes,
Ester waxes, polyolefin-polyether block copolymers, amide waxes, polyglycols, fatty acids, fatty alcohols, natural waxes and solid phosphoric acid derivatives. Preferred solid lubricants are WO 94/11
199 are hot melt particles. Liquid lubricants that can be used according to the present invention include:
Fatty acid esters such as glycerin triolate, sorbitan monooleate and sorbitan triolate, silicone oil derivatives and phosphoric acid derivatives.

The protective layer of the recording material of the present invention may contain a matting agent. Suitable matting agents are described in WO 94/11198 and include, for example, talc particles, which can optionally protrude from the protective layer.

According to a preferred embodiment of the substantially non-photosensitive black-and-white monosheet thermographic recording material of the present invention,
A protective layer containing a second polymer having active hydrogen atoms and a second polyisocyanate is provided on the heat-sensitive element.

Antihalation layer In addition to this component, the thermographic recording material used in the present invention has also passed through a thermosensitive element for absorption by a dye that converts absorbed infrared light into heat. Antihalation or acutance dyes that absorb infrared light and thereby prevent its reflection
yes). Such dyes can be incorporated into the thermosensitive element or any other layer of the recording material of the present invention.

Coating Method The coating of any layer of the substantially non-light sensitive black-and-white thermographic recording material used in the present invention can be, for example, a Modern Coating and Drying.
Technology, edited by Edw
ard D. Cohen and Edgar B. G
utoff, (1992) VCH Publisher
rs Inc. , 220 East 23rd Str
eet, 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 printing Direct thermal imaging is performed in analog fashion by direct exposure through the image or reflection from the image or by using an infrared heat source, for example using a Nd-YAG laser or other infrared laser or This is done by applying heat image-wise on a pixel-by-pixel basis in a digital fashion by direct thermal imaging using a thermal head.

The thermal printing image signal is converted into an electric pulse, which is then driven by a driver circuit.
it) to the thermal printhead. Thermal printheads consist of microscopic heat resistor components, which convert electrical energy to heat via the Joule effect.
Thus, the electrical pulse converted to a thermal signal appears as heat transferred to the surface of the thermal paper, where the chemical reaction that results in color development occurs. Such a thermal printhead can be used in contact or close contact with the recording layer. Normal thermal print head operating temperature is 3
The heating time per pixel can be less than 1.0 millisecond, in the range of 00-400 ° C .;
The pressure contact between the thermal printhead and the recording material can be, for example, 200-500 g / sec to ensure excellent heat transfer.
cm ² .

To avoid direct contact between the thermal print head and the recording layer not provided with the outermost protective layer,
Image-wise heating of the recording layer using a thermal printhead can be performed via a resin sheet or web that is in contact but can be removed and from which transfer of the recording material cannot occur during heating. .

The image signal for modulating the laser beam or current in the micro-resistor of the thermal printhead connects directly or possibly to a digital imaging workstation capable of processing the image information to meet specific requirements. Obtained from an intermediate storage means which can be done.

The activation of the heating element can be power-modulated or pulse-length modulated at a constant power. EP-A 654 355 describes an image forming method by image-wise heating using a thermal head having a heating component to which a voltage can be applied, in which activation of the heating component is a duty cycle.
cled) in a pulsed manner. When used in thermographic recordings operated with thermal printheads, the imaging materials are not suitable for reproducing images having a very large number of gray levels as required for continuous tone reproduction. EP-A 622 217 discloses an imaging method using a direct thermal imaging element which produces an improvement in continuous tone reproduction. Image-wise heating of the thermographic material can also be accomplished using an electrically resistive ribbon introduced into the material. Image-wise or pattern-wise heating of the thermographic material can also be performed using pixel-wise modulated ultrasound.

Industrial Application Thermographic imaging is transparency (tra
nsparences and reflective prints. The use of the present invention in the field of graphic images requiring high contrast images having a very steep dependence of print density on applied dot energy is contemplated. In the field of hard copy thermographic recording materials on a white opaque base are used, whereas in imaging procedures operated with light boxes, black imaged transparency is widely used.

Hereinafter, the present invention will be exemplified by Examples of the present invention and Comparative Examples. The percentages and ratios given in these examples are by weight unless otherwise indicated. The components used in the examples and comparative examples of the invention other than those listed above are as follows: in the thermosensitive element: organic silver salt: AgBeh = silver behenate; binder: BR 18 = PIOLOFORM ^™ BR 18, WA
Polyvinyl butyral from CKER CHEMIE; LL4160 = PIOLOFORM ^™ LL4160 =
Polyvinyl butyral from PACKER CHEMIE • Reducing agent: R01 = ethyl 3,4-dihydroxybenzoate

[0074]

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Polyisocyanate: N100 = BAY
DESMODUR ^™ N100 from ER; Toning agent: T01 = benzo [e] [1,3] oxazine-2,4-
Dione; T02 = 7- (ethyl carbonate) -benzo [e]
[1,3] oxazine-2,4-dione; silicone oil: Oil = BAYSILON ^™ MA;
Polydimethylsiloxane from BAYER; Stabilizer: S01 = tetrachlorophthalic anhydride; S02 = 3'-decanoylamino-1-phenyl-1H
-Tetrazole-5-thiol

[0076]

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S05 = 2- [2′-hydroxy-3 ′,
5 '-(Di-t-butyl) phenyl) -5-chlorobenzotriazole, TINU from CIBA-GEIGY
VIN ^™ 327;

[0078]

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S07 = Zinc oxide and the following additional components in the protective layer: MICRODOL ^™ SUPER, Norwegia
talc from n Talc AS; TEGOGLIDE ^™ 410, Goldschmi
Polysiloxane / polyether block copolymer from dt; SYLOID ^™ 72, colloidal silica from GRACE.

[0080]

EXAMPLES Examples 1 to 6 and Comparative Examples 1 to 9 of the present invention Preparation of heat-sensitive element A composition containing 2-butanone as a solvent / dispersing medium was coated on an undercoated polyethylene terephthalate support having a thickness of 120 µm. Doctor Blade-Coated, 85
After curing for 3 minutes at 0 ° C., a heat-sensitive element having the composition summarized in Table 1 below was obtained thereon: AgBeh = 3.149 g / m ² BR 18 = 3.149 g / m ² R01 = 0.643 g / M ² T01 = 0.172 g / m ² Oil = 0.012 g / m ² S01 = 0.075 g / m ² S02 = 0.068 g / m ² N100 = 0.315 g / m ² Then, Comparative Examples 1 to 9 Further, the following protective layer composition was overcoated on the thermosensitive element of the thermographic recording materials of Examples 1 to 6 of the present invention, and hardened at 85 ° C. for 3 minutes.

[0081]

[Table 1]

Thermographic printing The printer was equipped with a thin film thermal head with a resolution of 300 dpi and a line time (line) of 6.5 milliseconds.
time (the line time is the time required to print one line). During this line time, a constant power was applied to the printhead. The average printing power, which is the total amount of electrical input energy during one line time divided by the line time and the surface area of the heating resistor, is 1.6 m.
J / dot, which was sufficient to obtain the maximum optical density in each of the thermographic recording materials of Comparative Examples 1 to 9 and Examples 1 to 6 of the present invention.

[0083] In each gray scale step corresponding to data levels of 64 and 0 MACBETH ^TM T
The maximum and minimum densities of the prints were measured using a R924 densitometer through a visible filter and are shown in Table 2.

Shelf Life Test The shelf life of the thermographic recording materials of Comparative Examples 1 to 9 and Examples 1 to 6 of the present invention was measured by comparing the observed maximum density change, ΔD _max, and CIELAB at minimum density.
Evaluation was based on changes in a * and b * values. CIELA
The B-value is an R (45/0) geometry (geometr)
y) by ASTM Norm E308 by spectrophotometry according to ASTM Norm E179-90
Determined using an evaluation according to -90. The results are summarized in Table 2.

Light Stability Test Sunlight tests were performed on the thermographic recording materials of Comparative Examples 1-9 and Examples 1-6 of the present invention using SUNEST CPS from HERAEUS. 700 nm
Through a glass filter that removes infrared light with higher wavelengths and ultraviolet light with wavelengths below 310 nm,
A low pressure xenon lamp N of about 110 kLux under ambient conditions
The thermographic recording material was exposed to the luminous flux from XE 1500. The results are summarized in Table 2.

[0086]

[Table 2]

The non-chlorine-containing stabilizer STAB 0 compared to the thermographic material of Comparative Example 1 without stabilizer.
In the case of the thermographic recording materials of Examples 1 to 6 of the invention having 3, 05, 07, 08 and 13 the CIELAB- of the image background of the print after a 240-hour daylight test
The rise in b * value is clearly less, ie during the daylight test
The neutrality of the image tones was better preserved. CIELA
As can be seen by the changes in Ba- * and -b * values, the stability of the background image tones of the thermographic recording materials of Examples 1 and 2 of the present invention with stabilizers STAB 13 and STAB 07, respectively, is non-chlorine containing Stabilizer STAB 0
3, significantly worse than that of Examples 3-6 of the invention with STAB 05 and STAB 08.

This is a non-chlorine-containing 2- (2′-hydroxyphenyl) benzotriazole derivative (stabilizer ST
AB 03, 05, 07 and 08) and non-chlorine containing 2
-Hydroxy-benzophenone derivative (stabilizer STAB
13) shows an improvement in the stability of the image background and in particular its image tone when simulated exposure of the thermographic recording material having 13) to direct sunlight, when compared to a thermographic recording material without them.

Comparative Examples 10 to 14 and Example 7 of the Present Invention The present invention was repeated except that the protective layer was as shown in Table 3 below and was cured at 90 ° C. for 3 minutes instead of 85 ° C. for 3 minutes. Of the substantially non-photosensitive black-and-white mono-sheet thermographic recording materials of Comparative Examples 10 to 14 and Example 7 of the invention as described in Examples 1 to 6 and Comparative Examples 1 to 9 The element was manufactured.

[0090]

[Table 3]

Examples 7 and 7 of the present invention and Comparative Examples 1 to 9 of the present invention and Comparative Examples 1 to 9 except that the thermographic recording material was also subjected to a 5-day BB test. Thermographic evaluation of 10-14 substantially non-photosensitive black-and-white mono-sheet thermographic recording materials was performed. In the BB test, the thermographic recording material was subjected to Siefried Theimer under ambient conditions for 5 days.
GmbH, 6484 Birnstein, Germany
It was placed just one meter below a 2000W halogen lamp THS3007 from y. This light source is UVA (320
380 nm), UVB (280-320 nm) and U
It emits light of VC (less than 280 nm). All results are shown in Table 4.

[0092]

[Table 4]

From the results of the thermographic evaluation of the thermographic recording materials of Comparative Examples 10 to 14 and Example 12 of the present invention, it was found that when zinc oxide was used as a UV-absorber in the protective layer, the thermographic recording material of Example 7 of the present invention was obtained. Significantly higher yellowing of the image as seen with the thermographic recording materials of Comparative Examples 10 to 14 as well as in the 5 day BB test as compared to the CIELAB-a * value of the image background of the recording material print. Especially CIEL
It is clear that this results in less stability of the background image tone with respect to the AB-a * value.

Thus, the introduction of zinc oxide, a known inorganic UV-stabilizer, into thermographic recording materials is:
Does not produce stability against direct sunlight.

Comparative Example 15 and Examples 8 to 1 of the Present Invention
6 T01 with T02 in place of, adding R02 of 0.102 g / m ² in the heat-sensitive element, other than the protective layer were as shown in Table 5 below Examples 1-6 and Comparative Examples 1-9 The heat-sensitive elements of substantially non-light-sensitive black-and-white mono-sheet thermographic recording materials of Examples 8-16 of the present invention and Comparative Example 15 were prepared as described in the case.

[0096]

[Table 5]

Examples 1 to 6 of the present invention and Comparative Examples 1 to
The thermographic evaluation of the substantially non-photosensitive black-and-white monosheet thermographic recording materials of Examples 8 to 16 of the present invention and Comparative Example 15 was performed as described in Case 9. The results are summarized in Table 6.

Comparative Example 15 and Examples 8 to 1 of the Present Invention
The thermographic result of the thermographic recording material of No. 6 shows that in the case of the thermographic recording material containing the stabilizers STAB 03, 05, 07 and 13 the increase in the CIELAB-b * value of the image background of the print after a 240-hour sunlight test The thermographic recording materials of Examples 1 to 6 of the present invention show that the neutrality of the image was better preserved during the daylight test than that of the thermographic material of Comparative Example 15 which contained no stabilizer. The results obtained with were confirmed.

[0099]

[Table 6]

This is a non-chlorine-containing 2- (2′-hydroxyphenyl) benzotriazole derivative (stabilizer ST
AB 03, 05 and 07) and non-chlorine-containing 2-hydroxy-benzophenone derivatives (stabilizer STAB 1
3) shows an improvement in the stability of the image background and especially its image tone when simulated exposure of the thermographic recording material having 3) to direct sunlight when compared to a thermographic recording material without them.

Example 17 of the Invention Stabilizer in Both Heat Sensitive Element and Protective Layer In the case of Examples 1-6 of the invention and Comparative Examples 1-9, except that the composition of the heat sensitive element was as follows: substantially non embodiment 17 of the present invention as described - to produce a thermosensitive element of a photosensitive black and white monosheet thermographic recording ^{material: AgBeh = 3.89g / m 2 BR} 18 = 3.89g / m 2 STAB ^{03 = 0.15g / m 2 R01 =} 0.855g / m 2 T02 = 0.219g / m 2 Oil = 0.144g / m 2 S01 = 0.094g / m 2 S02 = 0.085g / m 2 N100 = 0.401 g / m ² The following protective layer composition was overcoated next to the thermosensitive element of the thermographic recording material of Example 17 of the present invention,
Minutes to ^{dura: BR 18 = 1.844g / m 2} MICRODOL TM SUPER = 0.184g / m 2 STAB 03 = 0.228g / m 2 Oil = 0.012g / m 2 N100 = 0.183g / m 2 A thermographic evaluation of the substantially non-photosensitive black-and-white mono-sheet thermographic recording material of Example 17 of the present invention was performed as described in Examples 1-6 of the present invention and Comparative Examples 1-9. . The results are summarized in Table 7.

[0102]

[Table 7]

When the stabilizer used in the present invention is used in both the heat-sensitive element and the protective layer of the thermographic recording material of Example 17 of the present invention according to the present invention, CIELAB after exposure to a 2000 W halogen lamp for 5 days. The increase in the b * value is less pronounced when the same stabilizer STAB03 is used only in the protective layer (see Example 12 of the present invention).

Examples 18 to 26 of the present invention Example 1 of the present invention except that the composition of the heat-sensitive element was as shown in Table 8, and the material was hardened at 85 ° C for 15 minutes without overcoating the protective layer. The heat-sensitive elements of the substantially non-light-sensitive black-and-white monosheet thermographic recording materials of Examples 18-26 of the present invention were prepared as described in Examples 6-9 and Comparative Examples 1-9.

[0105]

[Table 8]

Sliding of a separable 5 μm thick polyethylene terephthalate ribbon, in which the subbing layer, the heat-resistant layer and the sliding layer (anti-friction layer) are continuously coated, giving a ribbon having a total thickness of 6 μm Thermographic printing was performed as described in Examples 1-6 of the present invention and Comparative Examples 1-9 except that the printhead was separated from the imaging layer by a thin intermediate material in contact with the layer .

The shelf life test was performed as described in Examples 1 to 6 and Comparative Examples 1 to 9 of the present invention, and the image evaluation was performed as described in Examples 1 to 6 and Comparative Example 1. I went to. The results are summarized in Table 9.

Light Box Test The stability of the image background of the blinds made with the thermographic recording materials of Examples 18-26 of the present invention to post-image development exposure was set at 30 ° C. and 85% relative humidity. Evaluation was performed by exposing a new print for 3 days on a white PVC window of a specially assembled light-box placed in a VOTSCH ^™ conditioning shelf. Only the central area of the 550 mm long and 500 mm wide window was used to load the test material to ensure uniform exposure.

The stainless steel light box used was 650 mm in length, 600 mm in width and 1 in height.
20 mm wide and 610 mm long with an opening 560 mm wide, with a 10 mm wide and 5 mm deep edge around the opening so that it is 630 mm long and 5 mm wide
Forming platform for 80mm white PVC 5mm thick board, white PVC-board is light-
It is flush with the top surface of the box to prevent light loss from the light-box except through the white PVC-plate. This light box has 9 Ps with a diameter of 27 mm.
A LANILUX ^™ 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 a white PVC plate. Mounted 30 mm below the bottom and 35 mm below the material to be tested.

ASTM in R (45/0) geometry
Background L *, a * and b * CIEL determined by spectrophotometry according to Norm E179-90 using an evaluation according to ASTM Norm E308-90
The suitability of the material was evaluated based on the AB value. The results are shown in Table 9.

[0111]

[Table 9]

The light box a * and b * measurements are based on a * and b *-values that exceed the a * and b * -values of the new print.
It shows excellent image tone stability for the background as indicated by the small increase in value. This is the second embodiment of the present invention.
This is especially the case for the thermographic recording materials of 1, 22, 25 and 26.

Examples 27-34 of the Invention Stabilizers in Both Heat-Sensitive Element and Protective Layer The heat-sensitive elements of the substantially non-photosensitive black-and-white monosheet thermographic recording materials of Examples 27-34 of the invention are each Inventive Examples 19 to 26 correspond to the heat-sensitive element of the substantially non-light-sensitive black-and-white monosheet thermographic recording material. The thermosensitive elements of the thermographic recording materials of Examples 27 to 34 of the present invention were overcoated with the protective layer composition shown in Table 10 and finally hardened at 85 ° C for 3 minutes.

[0114]

[Table 10]

The thermographic evaluations of the substantially non-photosensitive black-and-white monosheet thermographic recording materials of Examples 27-34 of the present invention were performed as described in Examples 18-26 of the present invention. The results are summarized in Table 11.

[0116]

[Table 11]

The light box a * and b * measurements for the thermographic recording materials of Examples 29 to 34 of the present invention were performed using the heat sensitive elements of the same composition.
A lower than in the case of the thermographic recording material 26
The * and b * -values are indicated, suggesting that providing 2.1 mol% of STAB 07 to the protective layer provides additional stabilization in the image background. This is especially true for the thermographic recording materials of Examples 30, 31, 32, 33 and 34 of the present invention, in which case 3.
B of 91, 4.12, 4.07, 3.86 and 3.44
* Values were measured.

Having described in detail preferred embodiments of the present invention, it will be appreciated that numerous modifications may be made therein without departing from the scope of the invention as defined in the appended claims. It will be clear to the skilled person in the field.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Gi Jyansen Belgian 2640 Malt Cell Septes Trat 27 Agfa-Gevuert Na Mroseh Fennoutjap

Claims (4)

[Claims] 1. A heat-sensitive element comprising a support and a heat-sensitive element, said heat-sensitive element comprising a substantially non-photosensitive organic silver salt, a reducing agent and a binder therefor in a thermal working relationship therewith, -The chlorine-containing stabilizer is 2- (2'-hydroxyphenyl)
A substantially non-photosensitive black-and-white non-chlorine-containing stabilizer-containing monosheet thermographic recording material selected from the group consisting of benzotriazole derivatives and 2-hydroxy-benzophenone derivatives. 2. The thermographic recording material according to claim 1, wherein the non-chlorine-containing 2- (2′-hydroxyphenyl) benzotriazole derivative contains a 2-hydroxy-benzophenone group. 3. (i) bringing the outermost layer of the thermographic recording material according to claim 1 or 2 close to a heat source;
(Ii) forming an image by applying image-wise heat from the heat source to the thermographic recording material while in close proximity to the heat source; (iii) removing the thermographic recording material from the heat source. . 4. Substantially comprising a support and a heat-sensitive element, said heat-sensitive element comprising a substantially non-photosensitive organic silver salt, a reducing agent and a binder therefor in a thermal working relationship therewith. As a stabilizer against direct sunlight in a non-photosensitive black-and-white monosheet thermographic recording material.
Use of a non-chlorine-containing stabilizer selected from the group consisting of (2'-hydroxyphenyl) benzotriazole derivatives and 2-hydroxy-benzophenone derivatives.