JPH09258365A - Thermosensitive recording material for ir laser - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase the absorption efficiency for IR laser light, to decrease the coloring degree of the base, and to enable high quality recording. SOLUTION: This thermosensitive recording material for an IR laser consists of a supporting body and a thermosensitive layer containing at least an org. silver salt, a developer for the org. silver salt, a tricarbocyanine dye having at least two acid groups and a water-soluble binder formed on the supporting body. In this method, the tricarbocyanine dye is included in the thermosensitive layer in such a state that the max. absorption wavelength of the dye ranges from 650 to 1300nm and is longer by 50nm or more than the max. absorption wavelength of an aq. soln. of the dye. At least one of the org. silver salt or the developer for the org. silver salt is preferably prepared in a microcapsule state.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a heat-sensitive recording material, and more particularly to a non-contact heat-sensitive recording material for infrared laser which records by utilizing infrared laser light.

[0002]

2. Description of the Related Art A thermal head is brought into close contact with a surface of a heat-sensitive recording material having a heat-sensitive recording layer (hereinafter referred to as a heat-sensitive layer) provided on a support, and heat energy is transferred to the heat-sensitive layer directly or through a protective layer. Thermal recording systems for recording images are widely known, and are applied to facsimile machines, printers, and the like.

However, in such a thermal recording method, since the thermal head is brought into close contact with the thermal recording material for scanning, the thermal head is worn or the components of the thermal recording material are scum on the surface of the thermal head. There are drawbacks that a recorded image cannot be obtained correctly due to the adhesion, and that the thermal head is destroyed. In addition, the thermal recording method using such a thermal head has limitations in high-speed control of heating and cooling of heating elements and increase in heating element density due to the structural characteristics of the thermal head. There was a drawback that there was a limit to high-density recording and high-quality recording.

In order to solve the above-mentioned disadvantages of the thermal recording method using a thermal head, it has been proposed to perform thermal recording at high speed and high density without contact with a thermal recording material using a laser beam. (For example, Japanese Patent Application Laid-Open
No. 3617, JP-A-54-121140, JP-A-57
-11090, JP-A-58-56890, JP-A-5-5680
8-94494, JP-A-58-134791, JP-A-58-145493, JP-A-59-89192,
JP-A-60-205182, JP-A-62-56195
Issue).

However, in such a recording method using a laser beam, the heat-sensitive layer generally does not easily absorb light in the visible and near-infrared regions. There is a drawback that energy is not obtained and it is extremely difficult to produce a small and inexpensive device. Japanese Patent Publication No. 50-774 proposes a method in which microcapsules containing ink are applied to a base paper, and a strong light is applied to eject the ink in the capsule to record on the base paper. Is so low that it has not yet been put to practical use.

[0006]

Therefore, many proposals have been made for efficiently absorbing laser light in the heat-sensitive layer. Generally, a light-absorbing substance matching the wavelength of laser light is provided in the heat-sensitive layer. Is being added. in this case,
If the light absorbing substance to be added is not white, the background of the recording material is colored, and only low quality contrast and poor quality recording can be obtained.

Generally, white light absorbing substances are mostly inorganic compounds, but most of them have low light absorbing efficiency. On the other hand, organic compounds suitable for absorbing laser light are generally colored because they also absorb light in the visible light region, and
The darker the color, the higher the light absorption efficiency. Therefore, if it is added to the heat-sensitive layer as a light absorbing substance, the sensitivity can be increased, but it is difficult to improve the whiteness of the recording paper.

The present invention has been made in consideration of the above facts, and has a high absorption efficiency of infrared laser light, less coloring of the background, and enables high quality recording for infrared laser. The purpose is to provide a recording material.

[0009]

The present inventors have proposed that an infrared laser containing at least an organic silver salt, a developer of an organic silver salt, a specific tricarbocyanine dye, and a water-soluble binder in a heat-sensitive layer. It was found that very good results can be obtained when recording was performed using the.

That is, in the present invention, a heat-sensitive layer containing at least an organic silver salt, a developer of an organic silver salt, a tricarbocyanine dye having at least two acidic groups, and a water-soluble binder is provided on a support. Which is a thermosensitive recording material for infrared laser, wherein the tricarbocyanine dye has a wavelength of 50 nm or more longer than the absorption maximum wavelength of the aqueous dye solution and has the absorption maximum wavelength in the range of 650 to 1300 nm. It is contained in.

In the above invention, at least one of the organic silver salt and the organic silver salt developer can be microencapsulated.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail.

The organic silver salt contained in the heat-sensitive layer of the heat-sensitive recording material for infrared laser of the present invention is a colorless or white silver salt which is stable to light, and when heated with a developer, It produces silver by a redox reaction. Such an organic silver salt is a silver salt of an organic compound having an imino group, a mercapto group or a carboxyl group, and specific examples thereof include the following.

1) Silver salt of organic compound having imino group Saccharin silver, phthalazinone silver, silver benzotriazole, etc. 2) Silver salt of organic compound having mercapto group or thione group 3- (2-carbonylethyl) -4-oxy Methyl-4
-Silver salt of thiazoline-2-thione, 3-mercapto-4
Silver salts of organic compounds having a carboxyl group, such as silver stearate and silver behenate.

Of these, from the viewpoints of being white and stable to light, having excellent moisture resistance, being able to be used in combination with a mild developer, being known as an excellent toning agent, etc. Most preferred is silver behenate.

In the heat-sensitive recording material for infrared laser of the present invention, it is preferable to use a desalted and refined organic silver salt from the viewpoint of recording a high-concentration image by using a high-concentration organic silver salt. . Here, desalting refining means, for example, when an organic silver salt is prepared by adding silver nitrate to a salt of a reacting organic acid formed by adding an alkali to an organic acid, by-product of addition of the silver nitrate. The removed nitrate is removed from the system. Such desalting purification is preferably performed by an ultrafiltration method using a semipermeable membrane that allows the passage of nitrate but not the organic silver salt, or a centrifugation method.

The developer used in the present invention is a reducing agent which has the action of reducing an organic silver salt to produce silver when heated, and which undergoes a rapid reduction reaction at the development temperature.
It is required to have characteristics such as not affecting the color tone of the image after development.

Examples of such developers include hydroxycoumarone or hydroxycoumarans, sulfamidophenols or sulfamidonaphthols, hydradones, hirooxamic acids, bis-β-naphthols, indane-1,3. -Diones, aminophenols or aminonaphthols, pyrazolin-5-ones, hydroxylamines, reductones, hydrazines, hydroquinones, bisphenol A, bisphenol B
Such as polyphenols, gallic acid, gallic acid ester,
Phenylenediamines, hydroxyindanes, 1,4
-Dihydroxypyridines, amide oximes, hydroxy-substituted aliphatic carboxylic acid aryl hydrazides, N-
Hydroxyureas, phosphonamidophenols, phosphonamidoanilines, α-cyanophenylacetic esters, sulfonamidoamilines and the like, among these, each compound represented by the following formula, octyl gallate, It is preferable to use propyl gallate, ethyl gallate or methyl gallate.

[0019]

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In the present invention, from the viewpoint of preventing the reduction reaction between the organic silver salt and the developer at room temperature to prolong the shelf life of the thermal recording material for infrared laser and to reduce the fogging with time, It is preferable to encapsulate at least one of the organic silver salt developers in microcapsules. When only one of the organic silver salt and the developer of the organic silver salt is microencapsulated, the other is used by solid-dispersing it, or it is dissolved in an organic solvent to form an oil phase, which is then highly soluble It can be used in the form of a dispersion obtained by mixing and emulsifying with an aqueous phase containing molecules. In the latter case, the heat-sensitive layer can be made transparent. When both the organic silver salt and the developer of the organic silver salt are microencapsulated, they may be encapsulated in separate microcapsules or in the same microcapsule.

As a method for solid-dispersing the organic silver salt in the present invention, for example, an organic silver salt and a water-soluble polymer compound such as polyvinyl alcohol, and if necessary, a color tone agent, an antifoggant, a dispersant, Disperse to several microns or less with a ball mill, a sand mill or the like in combination with water. On the other hand, the reducing agent is similarly solid-dispersed or completely dissolved in an aqueous solution such as polyvinyl alcohol. The respective liquids thus obtained are blended to prepare a solid dispersion coating liquid, which is coated on a support to obtain a recording material.

The microcapsules usable in the present invention are
It is a thermo-responsive microcapsule that isolates a substance contained at room temperature, is not destroyed by pressure, heat, or the like at the time of heating, and makes the wall of the microcapsule material-permeable.

As a method for producing such microcapsules, known production methods such as an interfacial polymerization method, an internal polymerization method, and an external polymerization method can be adopted. In particular, an organic silver salt or an organic silver salt is used. An oil phase component obtained by adding a capsule wall material (polymer substance) to a core substance obtained by dissolving or dispersing a developer in an organic solvent, and then emulsifying it in an aqueous solution in which a water-soluble polymer is dissolved. It is preferable to adopt an interfacial polymerization method in which a wall made of a polymer of the capsule wall material is formed around the.

As the organic solvent, it is preferable to use a non-aqueous solvent having a boiling point of 150 ° C. or less such as carboxylic acid ester such as ethyl acetate, butyl acetate, isoamyl acetate, toluene, xylene, phosphoric acid ester and the like.

The reactant forming the capsule wall material is added inside the oil droplet and / or outside the oil droplet.

Specific examples of the capsule wall material include polyurethane, polyurea, polyamide, polyester, polycarbonate, urea-formaldehyde resin, polyamic acid, polystyrene, styrene methacrylate copolymer, styrene-acrylate copolymer and the like.
Preferred capsule wall materials are polyurethane, polyurea, polyamide, polyester, and polycarbonate, and polyurethane and polyurea are preferred because capsules that are hard to break are obtained. These polymer substances can be used in combination of two or more kinds.

Specific examples of the water-soluble polymer include gelatin, polyvinylpyrrolidone, polyvinyl alcohol and the like.

For example, when polyurea or polyurethane is used as a capsule wall material, (a) polyisocyanate such as diisocyanate, triisocyanate, tetraisocyanate, polyisocyanate prepolymer and the like, and (b) diamine , Polyamines such as triamine and tetraamine, prepolymers containing two or more amino groups, piperazine or its derivatives, polyhydric alcohols, etc. or water can be easily reacted by an interfacial polymerization method in an aqueous solvent to easily form a microcapsule wall. Can be formed. The microcapsules in this case are preferable because their walls are dense.

For the composite wall made of polyurea and polyamide or the composite wall made of polyurethane and polyamide, for example, polyisocyanate and acid chloride or polyamine and polyhydric alcohol are used to adjust the pH of the emulsifying medium to be the reaction liquid. After that, it can be prepared by heating. For details of the method for producing a composite wall composed of these polyurea and polyamide, see JP-A-58-1983.
-66948. The capsule made of polyamic acid is formed, for example, by an interfacial reaction between a polystyrene-maleic anhydride copolymer and a polyvalent amine.

The following isocyanate compounds can be mentioned as particularly preferable wall materials for the microcapsules used in the infrared laser heat-sensitive recording material of the present invention.

The isocyanate compound used here is a known isocyanate monomer (1) urethane modified product, (2) allophanate modified product, (3) isocyanurate modified product, (4) buret modified product, (5) ) Carbodiimide modified product, (6) modified product such as blocked isocyanate, and (7) Polymeric MDI, that is, 4,
Linear polymer of 4'-diphenylmethane diisocyanate (MDI).

The isocyanate monomers forming the modified product include tolylene diisocyanate (TDI), 4,
4'-diphenylmethane diisocyanate (MDI),
Xylylene diisocyanate (XDI), naphthylene diisocyanate (NDI), paraphenylene diisocyanate (PPDI), tetramethyl xylylene diisocyanate (TMXDI), hexamethylene diisocyanate (HDI), dicyclohexylmethane diisocyanate (HMDI), isophorone diisocyanate (IP
DI), lysine diisocyanate (LDI), isopropylidene bis (4-cyclohexyl isocyanate)
(IPC), hydrogenated xylylene diisocyanate (hydrogenated X
DI), cyclohexyl diisocyanate (CHD
I), tolidine diisocyanate (TODI) and the like. The structure of this isocyanate monomer is shown below, but the isocyanate monomer used in the present invention is not limited to these. These are described in detail, for example, in "Synthesis, blending, functionalization and application development of latest polyurethane" (Technical Information Association, 1989).

[0033]

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[0034]

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These isocyanate monomers are used after being modified into various isocyanate modified products as described above for the purpose of improving unfavorable physical properties such as toxicity, controlling reaction rate and improving blending ratio. To be Next, the modified form will be described. (1) The urethane-modified product is obtained by modifying an isocyanate monomer (or diisocyanate) with a shortage of polyol. (2) The modified allophanate is formed by adding an isocyanate group to a urethane group. (3) The modified isocyanurate has an isocyanurate ring in the molecule and tends to have improved heat resistance. (4) The modified buret is a compound in which an isocyanate group is added to a urea bond, and is a compound from which free isocyanate is removed. (5) In the modified carbodiimide, a carbodiimide bond is generated from a 2 mol isocyanate group by a decarbonation reaction. Furthermore, after uretonimine is formed when the isocyanate is added, carbodiimide and uretonimine coexist in equilibrium. (6) Blocked isocyanate is obtained by reacting various blocking agents in order to temporarily mask the activity of the isocyanate group. As the blocking agent, phenol,
Phenolic blocking agents such as xylenol, oximes,
Active hydrogen compounds such as lactams and alcohols are exemplified.

Specific examples of the capsule wall material of the heat-sensitive recording material for infrared laser of the present invention include isocyanate compounds represented by the following formulas (a) to (k) in view of safety and easy availability. To be

[0037]

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[0038]

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The reactant forming the capsule wall material is preferably heated after emulsification and dispersion. The heating conditions are preferably 30 to 80 ° C. for 30 minutes to 4 hours. If the temperature is lower than 30 ° C., the reaction requires a long time and the reaction proceeds only incompletely. When the temperature exceeds ℃, it becomes difficult to control the reaction, which is not preferable.

For example, when an isocyanate compound is used as a capsule wall material, an oil phase component obtained by further adding at least one isocyanate compound to a dispersion liquid in which an organic silver salt is dispersed in the organic solvent as described above. , After adding to an aqueous solution containing a water-soluble binder such as gelatin,
Stirring is performed to obtain a dispersion in which the oil phase component is dispersed in an aqueous solution, and the entire dispersion is heated to, for example, about 40 to 90 ° C. to form a wall material of microcapsules.

At this time, the average particle size of the obtained microcapsules is preferably 0.1 to 3.0 μm,
More preferably, it is 0.2 to 1.2 μm. By controlling the particle diameter in the above range, the transparency of the heat-sensitive layer is improved, and there are advantages such that an image can be observed with transmitted light in a shark castene.

On the other hand, the tricarbocyanine dye having at least two acidic groups (hereinafter simply referred to as tricarbocyanine dye) used in the present invention is preferably represented by the following general formula 6.

[0043]

[Chemical 6]

In the above formula, Z ¹ and Z ² are each a non-metal atom forming a substituted or unsubstituted benzothiazole ring, benzoselenazole ring, indole ring, naphthothiazole ring, naphthoselenazole ring and benzindole ring. It is a group. R ¹ and R ² are each a substituted or unsubstituted alkyl group,
R ³ and R ⁵ are each a hydrogen atom or an atom necessary to form a 5-membered ring by linking; R ⁴ is a hydrogen atom or a monovalent group (provided that the group of atoms forming the ring in the di-substituted amino group is Excluding). X ⁻ is an anion, n is 1 or 2, and n is 1 when the tricarbocyanine dye molecule forms an inner salt.

The group substituting the non-metal atom group forming the benzothiazole ring, benzoselenazole ring, indole ring, naphthothiazole ring, naphthselenazole ring and benzindole ring represented by Z ¹ and Z ² is Sulfonic acid group, carboxylic acid group, hydroxyl group, halogen atom (eg, fluorine atom, chlorine atom, bromine atom, etc.), cyano group, substituted amino group (eg, dimethylamino group, diethylamino group, ethyl-4-sulfobutylamino group) And di (3-sulfopropyl) amino group, etc., or directly or 2
A substituted or unsubstituted alkyl group having 1 to 5 carbon atoms bonded to a ring through a valent linking group (for example, as an alkyl group, a methyl group, an ethyl group, a propyl group, a butyl group, or the like, a substituent group). Is a divalent linking group such as a sulfonic acid group, a carboxylic acid group and a hydroxyl group, and is -O- or -NHCO.
_{-, - NHSO 3 -, -} NHCOO -, - NHCONH
-, - COO -, - CO -, - , and the like - SO _2. ) And the like.

In this case, the sulfonic acid group means a sulfo group and
The salt is a carboxylic acid, which is a carboxyl group and its salt.
Meaning of inclusion. Examples of salts include Na and K
Alkali metal salts, ammonium salts and triethylan
Monium salt, tributylammonium salt and pyridinium
Examples thereof include organic ammonium salts such as sodium salt. Z above ¹
And Z^TwoAmong the nonmetallic atomic groups represented by, especially 1 or more
The benzindole ring with the above sulfonic acid group is preferred
Yes.

Preferable specific examples of the alkyl group represented by R ¹ and R ² include a methyl group, an ethyl group, an n-butyl group, an isopropyl group and an n-pentyl group having 1 carbon atom.
~ 5 lower alkyl groups and groups having a substituent such as a sulfonic acid group, a carboxylic acid group or a hydroxyl group in these groups are mentioned, and among these, especially a 2-sulfoethyl group,
Number of carbon atoms having a sulfonic acid group such as 3-sulfopropyl group, 3-sulfobutyl group and 4-sulfobutyl group, 2
A lower alkyl group of -5 is preferred.

Examples of the 5-membered ring formed by connecting R ³ and R ⁵ include an indene ring and a cyclopentine ring. Preferred examples of the monovalent group represented by R ⁴ include a lower alkyl group such as a methyl group, an aralkyl group such as a substituted or unsubstituted phenyl group and a benzyl group, a lower sarcoxy group such as a methoxy group, and a dimethylamino group. , A disubstituted amino group such as diphenylamino group and methylphenylamino group, an alkylcarboxoxy group such as acetoxy group, an alkylthio group such as methylthio group, a cyano group, a nitro group, and a halogen atom such as fluorine atom, chlorine atom and bromine atom. And the like. Specific examples of the anion represented by X include halogen ions such as Cl ⁻ and Br ⁻ , p-toluenesulfonate ion and ethylsulfate ion. Among the tricarbocyanine dyes described in detail above, those in which Z ¹ and Z ² are sulfo-substituted benzindole rings and R ¹ and R ² are sulfoalkyl groups are particularly preferable.

Specific examples of the tricarbocyanine dye represented by the general formula 6 include compounds represented by the following formulas 7 to 9 and compounds described in JP-A-3-226736. You can

[0050]

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[0051]

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[0052]

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The tricarbocyanine dye used in the present invention is 50 nm from the absorption maximum wavelength of the aqueous solution of the dye from the viewpoint of increasing the whiteness of the background of the thermal recording material for infrared laser and increasing the absorption efficiency of infrared laser. As described above, the heat-sensitive layer needs to have a long wavelength and a maximum absorption wavelength in the range of 650 to 1300 nm.

As a method for bringing the above state, a method of adsorbing a tricarbocyanine dye on the non-photosensitive halogenated particles; a method of dissolving and emulsifying the tricarbocyanine dye in a high boiling point oil; There is a method of solid-dispersing in the form of fine particles; or a method of allowing the tricarbocyanine dye to exist as an aggregate (aggregate). Among these methods, from the viewpoint of production suitability of the infrared laser heat-sensitive recording material, there is a method in which the tricarbocyanine dye is dissolved in water to form an aqueous solution and then the water is removed to allow the tricarbocyanine dye to exist as an aggregate in the heat-sensitive layer. preferable.

The tricarbocyanine dye may be contained in the core material of the microcapsule, but may be contained outside the microcapsule or in the wall of the microcapsule. Further, the tricarbocyanine dye may be contained in two or more places at the same time.

The water-soluble binder used in the present invention has a function of binding the developer and the microcapsules contained in the heat-sensitive layer and a function of adhering the heat-sensitive layer to the support. Examples of such a water-soluble binder include gelatin and / or a gelatin derivative (for example, phthalated gelatin), a water-soluble polymer such as polyvinyl alcohol, methylcellulose, carboxymethylcellulose, hydroxypropylcellulose, arabic gum, polyvinylpyrrolidone, casein, styrene- Examples include various emulsions such as butadiene latex, acrylonitrile-butadiene latex, polyvinyl acetate, polyacrylate, and ethylene-vinyl acetate copolymer.

The amount of binder used is preferably 0.5 to 5 g / m ² in terms of solid content.

In the present invention, from the viewpoint of accelerating the reduction reaction between the organic silver salt and the developer during heating, adjusting the color tone of the image and carrying out the rapid development, the heat sensitive layer contains a color tone agent. Is preferred.

This toning agent is preferably used when it is desired to form a dark image, particularly a black image, in the resulting image. The amount used ranges from about 0.0001 mol to about 2 mol, preferably from about 0.0005 mol to about 1 mol, per 1 mol of the organic silver salt. The effective toning agent varies depending on the organic silver salt used and the developing agent, but the most common toning agent is a heterocyclic organic compound containing at least two hetero atoms, and at least 1 in the hetero ring. There are individual nitrogen atoms.

These are described, for example, in US Pat.
No. 0,254. Specific examples of such a toning agent include, for example, phthalazone (phthalazinone), phthalic anhydride, 2-acetylphthalazinone, and 2-acetylphthalazinone.
Phthalylphthalazinone and others, JP-A-50-6713
Substituted phthalazinones such as those described in JP-A-2 are mentioned, and these are preferably used in the present invention.

Examples of other effective color toning agents include JP-A-4
Examples thereof include pyrazolin-5-ones, cyclic imides, and quinazolinone, as described in 6-6077. Specific examples of these include phthalimide, N-hydroxyphthalimide, N-potassium phthalimide, and silver phthalimide. Alternatively, phthalazinones are also effective as a toning agent.

Other effective color toning agents are disclosed in JP-A-49-
The mercapto compounds as described in 5019 and 49-5020 are mentioned. In addition, JP-A-5
Oxazinediones as described in JP-A-0-2542, phthalazinediones as described in JP-A-50-67641, uracils as described in JP-A-58-114217, US Patent No. 3,
N-hydroxynaphthalimides as described in the specification of No. 782,941; West German Patent Application Publication Nos. 2,140,406, 2,141,063 and 2,220,597. Substituted phthalimides, as described in US Pat.
Phthalazinone derivatives, such as those described in U.S. Pat. No. 0,618, can be used as well.

In the infrared laser heat-sensitive recording material of the present invention, it is preferable to take the following measures from the viewpoint of preventing thermal fogging and stabilizing the background after image formation.

First of all, it is well known that mercury compounds are very effective in preventing thermal fogging and stabilizing the background after image formation, but from the viewpoint of environmental pollution, it is not possible to use them. Since it is not preferable, in the present invention, JP-A-49-10724, JP-A-48-2842,
N, as described in JP-A-48-8194,
It is preferred to use N-halogeno compounds such as -halogenosuccinimide, N-halogenoacetamide, N-halogenooxazolinone, N-halogenopentazotriazole, and N-halogenobenzimidazole.

Further, US Pat. No. 3,645,739, JP-A-49-125016 and JP-A-49-1307.
No. 20, No. 50-57619, No. 50-39264 and the like; higher fatty acids; tetrahalogenophthalic acid or its anhydride, benzenesulfonic acid, arylsulfonic acid salts such as p-toluenesulfonic acid; benzene. Arylsulfinic acid such as sulfinic acid or p-toluenesulfinic acid or a salt thereof; higher fatty acid lithium salt such as lithium myristate, lithium stearate, lithium behenate, lithium barmitate, and lithium laurate is used as an acid stabilizer. be able to.

Other acid stabilizers include salicylic acid and p-
Alkyl-substituted benzoic acids such as hydroxybenzoic acid, tetraprombenzoic acid, tetrachlorobenzoic acid, p-acetamidobenzoic acid, p-t-butylbenzoic acid, phthalic acid, isophthalic acid, trimellitic acid, pyromellitic acid, dicitric acid, 5 '5'-Methylenebissalicylic acid, citric acid, tartaric acid, oxalic acid, boric acid, phosphoric acid, pyrophosphoric acid and the like are also effective. These acid stabilizers not only prevent thermal fogging, but also have the effect of preventing background discoloration upon exposure to white light after image formation and improving shelf life.

Other compounds effective for preventing heat fogging and photo-discoloration include benzotriazole and its derivatives, thiouracils, mercapto compounds such as 1-phenyl-5-mercaptotetrazole, and JP-A-47-3.
No. 18, azole thioethers or blocked azole thiones, US Pat. No. 3,700,
No. 457, tetrazolylthio compounds, 3,7
No. 07,377 and 4,108,455, a photosensitive halogeno organic oxidizer, and 3,874,946, 2,4-bis (tribromomethyl) -s-triazine, polybromoalkylsulfonyl. Polybrominated organic compounds such as compounds, trihalomethyltetrazole derivatives shown in Japanese Patent No. 4,546,075, trihalomethylbenzimidazoles and their benzoxazole counterparts, or benzothiazole counterparts, JP-A-59-572
R ^a —CX ₂ —R ^b (X is a halogen: R ^a , R ^b is acyl, oxycarbonyl, oxysulfonyl, alkylsulfonyl, allylsulfonyl,
A compound represented by a group such as aralkylsulfonyl, carboxyl, sulfo, sulfamoyl, etc.), an organic halogen compound shown in US Pat. No. 4,465,761,
2-trihalomethyloxazole derivatives shown in No. 4,452,885, heterocyclic compounds having a trihalomethyl group shown in No. 4,756,999,
The compounds represented by the following formulas disclosed in European Patent No. 622,666 are effective.

[0068]

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In the above formula, R ⁶ , R ⁷ and R ⁸ are each independently a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, a thioalkyl group, a perhalogenated alkyl group,
Or a cycloalkyl group.

The effect of the present invention is particularly remarkable when the above-mentioned heat fog photochromic inhibitor is used in combination with a thermoresponsive capsule.

Further, in order to swell the microcapsule wall at the time of heating with infrared laser light for forming the wall material of the microcapsule, a sensitizer is added in an emulsified dispersion or solid dispersion state to increase the thermal sensitivity. You can also

As the sensitizer, those which are solid at room temperature and have a melting point of 50 ° C. or higher, preferably 150 ° C. or lower, can be selected and used from among the plasticizers for polymers used as capsule wall materials. . For example, when the capsule wall material is made of polyurea or polyurethane, a hydroxy compound, a carbamate compound, an aromatic alkoxy compound, an organic sulfonamide compound, an aliphatic amide compound, an arylamide compound and the like are preferably used.

Further, in the present invention, it is possible to use a coloring aid. The color-forming auxiliary that can be used in the present invention is a substance that increases the color density during laser heating recording or lowers the minimum color-forming temperature. This is for creating a situation in which the developer and the developer easily react.

Examples of the coloring aid include phenol compounds, alcoholic compounds, amide compounds, sulfonamide compounds, and the like. Specific examples are p-tert-octylphenol, p-benzyloxyphenol, phenyl p-oxybenzoate, Examples thereof include benzyl carbanylate, phenethyl carbanylate, hydroquinone dihydroxyethyl ether, xylylene diol, N-hydroxyethyl-methanesulfonic acid amide, and N-phenyl-methanesulfonic acid amide. These may be contained in the core substance, or may be added outside the microcapsules as an emulsified dispersion.

The support used in the present invention may be transparent or opaque. Opaque supports include paper,
Examples thereof include synthetic paper, paper obtained by laminating a polymer film on paper, aluminum vapor-deposited base, and polymer film coated with a white pigment. In this case, in order to irradiate the laser beam from the heat-sensitive layer side and efficiently absorb the laser beam in the heat-sensitive layer, it is preferable to use a support having high reflectivity of the laser beam.

On the other hand, as the transparent support, it is preferable to use a support which does not absorb the irradiation laser light and has dimensional stability that does not deform with respect to the heat generated when the laser light is irradiated. In this case, recording can be performed by irradiating a laser beam through the transparent support. The thickness of the support is 10 μm to 200 μm.

Examples of such a transparent support include polyester films such as polyethylene terephthalate and polybutylene terephthalate, cellulose derivative films such as cellulose triacetate film, polystyrene films, polypropylene films, polyolefin films such as polyethylene films, and polyimide films. , Polyvinyl chloride film, polyvinylidene chloride film,
Examples thereof include polyacrylic acid copolymer films, polycarbonate films and the like, and these can be used alone or in combination. Films that can be used as the transparent support preferably have a haze (degree of cloudiness) of 3% or less.

The support used in the present invention is particularly preferably a polyester film which has been subjected to heat treatment and antistatic treatment.

The method for producing the film is not particularly limited as long as it can be carried out under the condition that the above object can be achieved. Specifically, there may be mentioned a method of producing a film by heating, melting and extruding, cooling, solidifying, stretching and heat fixing.

Further, the support may contain inorganic fine particles, antioxidants, antistatic agents, dyes and the like within a range not hindering the object of the present invention.

As the inorganic fine particles that can be used here, I
Group A, IIA, IVA, VIA, VIIA, VIII, I
Group B, IIB, IIIB, IVB, oxides, hydroxides, sulfides, nitrides, halides, carbonates, acetates, phosphates, phosphites, organic carboxylate of each element, Silicates,
Examples include titanates, borates and their hydrated compounds, composite compounds centered on them, and natural mineral particles.
Specifically, Group IA element compounds such as lithium fluoride, borax (sodium borate hydrate), magnesium carbonate, magnesium phosphate, magnesium oxide (magnesia), magnesium chloride, magnesium acetate, magnesium fluoride, magnesium titanate, silicate Magnesium, magnesium silicate hydrate (talc), calcium carbonate, calcium phosphate, calcium phosphite, calcium sulfate (gypsum), calcium acetate, calcium terephthalate, calcium hydroxide, calcium silicate, calcium fluoride, calcium titanate, titanic acid Group IIA element compounds such as strontium, barium carbonate, barium phosphate, barium sulfate and barium phosphite, titanium dioxide (titania), titanium monoxide, titanium nitride, zirconium dioxide (zirconia), and zirconium oxide IVA Group element compound, molybdenum dioxide,
Group VIA element compounds such as molybdenum trioxide and molybdenum sulfide, Group VIIA element compounds such as manganese chloride and manganese acetate, Group VIII element compounds such as cobalt chloride and cobalt acetate, Group IB element compounds such as cuprous iodide, Group IIB element compounds such as zinc oxide and zinc acetate, group IIIB element compounds such as aluminum oxide (alumina), aluminum oxide, aluminum fluoride, aluminosilicates (alumina silicate, kaolin, kaolinite), silicon oxide (silica, silica gel) ), Graphite, carpon, graphite, glass etc.
Particles of a group IVB element compound, natural minerals such as kernalite, kainite, mica (mica, kinmo), and virose ore. Above all, from the viewpoint of handleability,
Preferred are silica, talc, titania, alumina, calcium carbonate, calcium oxide, calcium chloride and the like, and mixtures thereof. Examples of the organic fine particles include fine particles such as cross-linked polystyrene and cross-linked polymethyl methacrylate. As the antioxidant, antistatic agent, dye and the like, known additives for resins can be blended according to the purpose.

In the present invention, when a polymer film or paper laminated with the polymer film is used as a support, or when a transparent support is used, in order to enhance the adhesiveness between the support and the heat-sensitive layer, these are used. It is preferable to provide an undercoat layer between the two.

As the material of the undercoat layer, gelatin, synthetic polymer latex, nitrocellulose, acrylic acid ester copolymer, polyvinylidene chloride, SBR, aqueous polyester and the like are used. The coating amount of the undercoat layer is 0.1 g / m
It is preferably in the range of ^{2 ~2.0g} / m ^2, preferably in the range particularly ^{0.2g / m 2 ~1.0g / m 2} .

The undercoat layer may be swelled by water contained in the heat-sensitive layer to deteriorate the image quality of the heat-sensitive layer when the heat-sensitive layer is applied on the undercoat layer. Therefore, the undercoat layer is cured with a hardener. Is desirable.

Examples of the hardener include, for example, JP-A-2-141.
No. 279 can be mentioned. The addition amount of these hardeners is in the range of 0.20% by weight to 3.0% by weight based on the weight of the undercoat layer, and an appropriate addition amount is selected according to the coating method and the desired degree of curing. be able to.

Depending on the hardener used, if necessary, caustic soda may be further added to bring the pH of the solution to the alkaline side, or the pH of the solution may be brought to the acidic side with citric acid or the like. Further, an antifoaming agent may be added to eliminate bubbles generated at the time of application, or an activator may be added to improve the leveling of the liquid and prevent the generation of coating streaks.

Further, it is desirable to activate the surface of the support by a known method before applying the undercoat layer. As the activation method, etching treatment with acid, flame treatment with a gas burner, corona discharge treatment, glow discharge treatment, or the like is used, but from the viewpoint of cost or simplicity, US Pat. No. 075,
No. 2,846,727, No. 3,549,406
No. 3,590,107 and the like are most preferably used.

In the present invention, in order to protect the heat-sensitive layer from sticking, solvents and the like, it is preferable to provide a protective layer containing a pigment on the heat-sensitive layer.

Examples of such pigments include mica, talc,
Calcium carbonate, zinc oxide, titanium oxide, aluminum hydroxide, kaolin, talc, fluorite, synthetic silicate, amorphous silica, urea formalin resin powder and the like,
Among these, calcium carbonate, aluminum hydroxide, kaolin, silica, mica and talc are particularly preferred.

The protective layer in the present invention contains aged polyvinyl alcohol, carboxy-modified polyvinyl alcohol, silica-modified polyvinyl alcohol and the like as a binder from the viewpoint of retaining the pigment and improving transparency. preferable.

The coating liquid for protective layer (referred to as protective layer liquid) in the present invention is obtained by mixing a pigment with the above-mentioned binder solution. Depending on the purpose, zinc stearate, calcium stearate, paraffin wax, polyethylene wax. Other additives such as lubricants and dispersants such as, fluorescent brightening agents, crosslinking agents, sulfosuccinic acid-based alkali metal salts and fluorine-containing surfactants, and polyoxyethylene surfactants may be further added. The heat-sensitive recording material for infrared laser of the present invention comprises, for example, an organic silver salt represented by the general formula RCOOAg dispersed in an organic solvent, and an oil phase component obtained by adding a polyvalent isocyanate to the water-soluble polymer. Addition and stirring in an aqueous solution containing to emulsify and disperse the oil phase component,
Then, by heating, to prepare a microcapsule liquid containing microcapsules containing the organic silver salt, further,
An organic silver salt developer and other additives are added to prepare a heat-sensitive layer coating solution, and a protective layer coating solution as described above is prepared, on a support, bar coating, blade coating, Air knife coating, gravure coating, roll coating coating,
Spray coating, by coating and drying by a coating method such as dip coating, heat-sensitive layer of 2.5~25g / m ² in solid weight, by providing a protective layer of 0.2~7g / m ² in solid weight Manufactured.

The coating amount of the organic silver salt and the developer is preferably 0.5 to 3.0 g / m ² , more preferably 0.8 to 2.0 g / m ² as the Ag component in the heat-sensitive layer. Is preferred. Further, it is desirable that the heat-sensitive layer is applied so that the thickness is 1 to 20 μm.

The coating liquid used in the present invention contains a pigment dispersant, a thickener, a flow modifier, and a pigment, as long as the properties of the present invention are not impaired.
An antifoaming agent, a defoaming agent, a release agent, a coloring agent, a wax, a hardener, and the like can be appropriately compounded as needed.

Further, if necessary, a backcoat layer may be provided on the surface of the support of the infrared-ray heat-sensitive recording material opposite to the color-forming layer. As the back coat layer, any of those known as a back coat layer of a thermosensitive recording material for infrared laser can be used.

The laser beam used in the present invention has a wavelength in the near infrared region. Specific examples thereof include a helium-neon laser, an argon laser, a carbon dioxide laser, a YAG laser, and a semiconductor laser.

In the present invention, when the heat-sensitive layer of the heat-sensitive recording material for infrared laser contains the carbocyanine dye in any one or more locations inside, outside or inside the wall of the microcapsule, the carbocyanine dye is used. Absorbs the irradiated laser light and converts the energy into heat energy. As a result, the microcapsules are heated to become substance permeable and the internal pressure increases,
Reactive substances inside and outside the microcapsules permeate and contact the walls of the microcapsules to develop color.

This carbocyanine dye is colored in the aqueous solution because it has a maximum absorption wavelength in the visible light region, but when the water content of the aqueous solution is removed and the carbocyanine dye is dried, the carbocyanine dye is not colored. Due to the association of the cyanine dye, the maximum absorption wavelength in the visible light region shifts to the long wavelength side, that is, the infrared region. Therefore, in the infrared laser heat-sensitive recording material according to the present invention, the heat-sensitive layer is colored at the time of application, but becomes colorless after drying, and the background of the infrared laser heat-sensitive recording material should be white or nearly colorless. In addition, the absorption efficiency of infrared laser light can be improved.

[0098]

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to the following examples. Unless otherwise specified in the text, "%" is "% by weight"
And “parts” means “parts by weight”.

(Example 1) Preparation of silver behenate 25.59 g of behenic acid was added to 480 g of water and heated to 90 ° C., and then an aqueous solution of 3.0 g of NaOH in 45 g of water was added and well stirred. Then, it cooled to 50 degreeC.

Then, to the resulting solution was added Ag to 75 g of water.
After an aqueous solution to which 12.9 g of NO ₃ had been added was added dropwise over 5 minutes, stirring was continued for 30 minutes to cause a reaction.

The reaction solution obtained was filtered through a filter cloth to obtain 800 ml of water.
After adding ml and stirring and washing, it was filtered again. After such a washing operation was repeated three times, the obtained solid content was reduced to 5%.
It was dried for 3 days by a blow dryer at 0 ° C. to obtain a dried solid of silver behenate.

Preparation of silver behenate / phthalazone co-dispersion solution 21.1 g was weighed from the adjusted silver behenate dry solid,
To this, 3.26 g of phthalazone, 15% aqueous solution of polyvinyl alcohol (trade name: PVA205, manufactured by Kuraray Co., Ltd.)
52.8 g and 103 g of ion-exchanged water were added, and the mixture was dispersed with a paint shaker for 3 hours to obtain a behenic acid / phthalazone co-dispersion having an average particle diameter of 0.6 μm or less.

Preparation of developer aqueous solution 22% polyvinyl alcohol (trade name: PVA203,
Methyl gallate 4.5 to 50.0 g (Kuraray Co., Ltd.)
g and ion-exchanged water 35.0 g were added, and the mixture was stirred at 60 ° C. for 1 hour to prepare an aqueous developer solution.

Preparation of Coating Solution for Heat-Sensitive Layer 8.0 g of the silver behenate / phthalazone co-dispersion solution, 4.0 g of the aqueous developer solution, 1.9 g of a 3% benzotriazole methanol solution, and the trivalent compound represented by Chemical Formula 7 above. 0.12 g of the carbocyanine dye was stirred and mixed to obtain a heat-sensitive layer coating solution.

32 g of adjusted water for the protective layer coating solution and 10% of carboxy-modified polyvinyl alcohol (trade name: PVA-KL-318, manufactured by Kuraray Co., Ltd.)
32 g of an aqueous solution of an epoxy-modified polyamide (trade name:
FL-71, manufactured by Toho Chemical Co., Ltd.) and 8 g of a 30% dispersion, 5 g of a 2% aqueous solution of polyoxyethylene (surfactant), and a dispersion of 20% zinc stearate (trade name:
Hydrin Z, 4 g of Chukyo Yushi Co., Ltd.) was added to obtain a protective layer coating solution.

Preparation of heat-sensitive recording material for infrared laser On the transparent polyethylene terephthalate support (130 μm / thickness) provided with an undercoat layer, the heat-sensitive layer coating solution was dried using a wire bar to give a dry film thickness of 10 g / m ^2. And then dried at 50 ° C. for 20 minutes.

Then, a coating solution for protective layer was further applied and dried on the coating film so that the solid content was 2.0 g / m ² , to obtain a thermal recording material for infrared laser.

From the heat-sensitive layer side of the heat-sensitive recording material for infrared laser produced as described above, a semiconductor infrared laser beam (GaAs junction laser) having a wavelength of 950 nm was imagewise irradiated to obtain a black recorded image. . The output of the laser was adjusted so that an energy of 40 mJ / mm ² was obtained for 1 millisecond on the surface of the heat-sensitive layer.

The transmission density of the colored portion of the obtained recorded image was measured using a Macbeth densitometer and found to be 2.52. Further, the coloring of the background of the heat-sensitive recording material for infrared laser was hardly recognized.

Example 2 Preparation of Capsule Solution Encapsulating Silver Behenate 27 g was weighed from the adjusted silver behenate dry solid, and 1.10 g of polyvinyl butyral and 1 of isoamyl acetate
Add 10 g, disperse for 3 hours with a paint shaker,
Further, it is dispersed in a motor mill and has an average particle diameter of 0.4.
A μm silver behenate dispersion was obtained.

An oil phase was prepared by adding 6 g of Takenate D-110N (trade name, manufactured by Takeda Pharmaceutical Co., Ltd .: an isocyanate compound having the structure of the formula (a) in Chemical Formula 4) as a capsule wall material to 10 g of the obtained dispersion liquid. As an ingredient. This was added to 10% polyvinyl alcohol (trade name: PVA21)
7E, 32 g of Kuraray Co., Ltd. aqueous solution and 80 g of water were added to a mixed solution (aqueous phase), and a homogenizer (Nippon Seiki, Ace Homogenizer) was used to obtain 8,000 rp.
m for 10 minutes.

The obtained fine emulsified dispersion was heated to 65 ° C. with stirring and kept for 3 hours to carry out the encapsulation reaction. Here, the weight ratio of the solid content to the silver behenate of the capsule wall material was about 2.7. The obtained liquid is a microcapsule liquid containing silver behenate and having an average particle size of 0.8 μm.

Preparation of coating liquid 4 g of water in 15 g of the capsule liquid containing silver behenate,
0.6 g of a 3% benzotriazole methanol solution, 2.8 g of the developer aqueous solution, and 0.4 g of the tricarbocyanine dye represented by Chemical Formula 8 were mixed to obtain a coating solution.

Preparation of thermal recording material for infrared laser In the same manner as in Example 1, the coating solution was dried to a film thickness of 20 g.
/ M ² and then the protective layer is coated and dried on the coating film so that the dry film thickness is 2.0 g / m ^2, and the infrared laser heat-sensitive recording material. Got

From the heat-sensitive layer side of the heat-sensitive recording material for infrared laser produced as described above, semiconductor infrared laser light (GaAs junction laser) having a wavelength of 910 nm was imagewise irradiated to obtain a blue recorded image. . The output of the laser was adjusted so that an energy of 40 mJ / mm ² was obtained for 1 millisecond on the surface of the heat-sensitive layer.

The transmission density of the colored portion of the obtained recorded image was measured using a Macbeth densitometer and found to be 2.38. Further, the background of the heat-sensitive recording material for infrared laser was colored a little greenish green, but it was not so disturbing.

(Example 3) In the same manner as in Example 1 except that the tricarbocyanine dye represented by the above chemical formula 9 was used in place of the tricarbocyanine dye used in Example 1, infrared laser heat-sensitive A recording material was prepared.

The infrared recording material for infrared laser thus obtained was
A semiconductor recording infrared laser beam (GaAs junction laser) having a wavelength of 985 nm was imagewise irradiated from the heat sensitive layer side to obtain a black recorded image. The output of the laser beam was 40 mJ per millisecond on the surface of the thermosensitive layer of the thermosensitive recording material for infrared laser.
/ Mm ² .

The transmission density of the obtained black recorded image was 2.48 when measured with a Macbeth densitometer.
Further, the background coloring of the heat-sensitive recording material for infrared laser was hardly seen.

Comparative Example 1 Infrared laser heat-sensitive recording was carried out in the same manner as in Example 1 except that an infrared absorbing dye represented by the following chemical formula 11 was used in place of the tricarbocyanine dye used in Example 1. When a material was produced, an image was recorded, and the transmission density thereof was measured, the transmission density of the colored portion of the obtained recorded image was 1.94 (Macbeth densitometer). Also,
The background of the thermal recording material for infrared laser was colored a little green.

[0121]

Embedded image

Comparative Example 2 Infrared laser heat-sensitive recording was carried out in the same manner as in Example 2 except that the infrared absorbing dye represented by the following chemical formula 12 was used in place of the tricarbocyanine dye used in Example 2. When a material was prepared, an image was recorded, and the transmission density thereof was measured, the transmission density of the colored portion of the obtained recorded image was 1.65 (Macbeth densitometer). Also,
The background of the heat-sensitive recording material for infrared laser was colored slightly blue-green.

[0123]

Embedded image

The maximum absorption wavelength (λ _max ) and half-width (maximum absorption wavelength (λ _max ) of the dyes or pigments used in Examples 1 to 3 and Comparative Examples 1 and 2 in an aqueous solution state and in a state of being added to the heat-sensitive layer were obtained. The absorption width at) / 2), the degree of coloring of the thermal recording material for infrared laser, and the transmission density of the colored portion of the recorded image are summarized in Table 1.

[0125]

[Table 1]

As seen from Table 1, in this example, the transmission density was higher than in Comparative Examples 1 and 2, that is, a recorded image with good color development was obtained, and the degree of background coloring was also in Comparative Example 1 and 2. You can see that it is thinner than 2. That is, it can be seen that in this embodiment, a recorded image with high contrast can be obtained. From the comparison between Example 1 and Comparative Example 1 and the comparison between Example 2 and Comparative Example 2, which differ only in the dye, it can be seen that the above effects are due to the tricarbocyanine dye. Furthermore, comparing the maximum absorption wavelengths of these tricarbocyanine dyes in an aqueous solution and after drying (heat-sensitive layer), the maximum absorption wavelength after drying is shifted by 50 nm or more to the infrared region side from the maximum absorption wavelength in the case of an aqueous solution. It can be seen that the maximum absorption wavelength after drying is contained in the range of 650 to 1300 nm. Further, since the full width at half maximum of the tricarbocyanine dye used in this example is narrower than the full width at half maximum of the infrared absorbing dye used in the comparative example, the tricarbocyanine dye used in this example has the maximum absorption wavelength. It can be seen that the peak is sharp and the sensitivity is good.

[0127]

Since the thermal recording material for infrared laser of the present invention contains the above-mentioned carbocyanine dye, it has a high absorption efficiency of infrared laser light, and has a low coloring of the background, which enables high-quality recording. To

If at least one of the organic silver salt and the organic silver salt developer is microencapsulated, fogging over time can be reduced.

Claims (2)

[Claims] 1. An infrared laser for which a heat-sensitive layer containing at least an organic silver salt, a developer of an organic silver salt, a tricarbocyanine dye having at least two acidic groups, and a water-soluble binder is provided on a support. A heat-sensitive recording material, wherein the tricarbocyanine dye has a wavelength of 50 nm or more longer than the absorption maximum wavelength of the dye aqueous solution, and 650 to 13
A heat-sensitive recording material for infrared laser, which is contained in the heat-sensitive layer in a state of having an absorption maximum wavelength in the range of 00 nm. 2. The heat-sensitive recording material for infrared laser according to claim 1, wherein at least one of the organic silver salt and the developer of the organic silver salt is microencapsulated.