JPH09254554A - Recording material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To record a high density image free from glitter and reduced in fog with high sensitivity by adding butadiene type latex containing butadiene as a polymerizing component to a recording layer. SOLUTION: A recording layer containing thermally responsive microcapsules including at least an organosilver salt or organosilver salt particles, a developer of an organosilver salt and butadiene type latex is provided on a support. As the butadiene type latex, latex containing a copolymer of butadiene and a monomer having a double bond such as maleic ester as a copolymer component is used. By this constitution, a recording material reduced in fog and imparting a high density recording image is obtained and the glitter of an image can be eliminated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording material which forms an image by dry processing, and more particularly to a dry recording material which can form a silver image using an organic silver salt.

[0002]

2. Description of the Related Art Photosensitivity and gradation of silver halide, and
A so-called dry silver developed by 3M (3M) in the United States is well known as a dry-processed light-sensitive material that has been practically used by solving the drawbacks of the wet processing of silver halide while maintaining good image quality. An organic silver salt, which is one of the essential constituents of this dry silver, is a colorless or white silver salt that is stable to light, and when heated with a reducing agent at 100 ° C. or higher, silver (image) ) Is used to produce silver behenate. Dry silver light-sensitive materials are generally prepared by adding a silver halide forming agent to a polymer dispersion of an organic silver salt prepared by dispersing an organic silver salt in a binder such as a polymer and converting a part of the organic silver salt into silver halide. A coating solution containing a silver halide and a reducing agent (developer) or various additives prepared separately in advance in a modified coating solution or a polymer dispersion of an organic silver salt is coated on a support. It is adjusted by drying to provide a photosensitive layer. In this case, regardless of the presence or absence of silver halide, an image can be obtained even when image information is applied by heat application of a thermal head, so that the dry silver recording material can be used as a heat sensitive recording material.
Such a recording material using an organic silver salt and a water-soluble polymer such as polyvinyl alcohol as a binder for a developer is described in WO94 / 16361 and the like.

However, when a silver image is formed on the recording material described in WO94 / 16361, the recorded portion is partially metallically glossed, and so-called image glare occurs. Such image glare gives an unpleasant impression and is not preferable. Further, if only the water-soluble polymer is used, the sensitivity and the color density are lowered, which is not preferable. Also, the occurrence of fogging is large.

[0004]

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide an excellent recording material using an organic silver salt, which is capable of recording a high-density image with high sensitivity and less fogging without image glare. To provide. A second object of the present invention is to provide a recording material having a transparent recording layer using an organic silver salt.

[0005]

Means for Solving the Problems As a result of intensive studies for solving the above problems, the present inventors have found that by using a butadiene-based latex as a binder for an organic silver salt,
The present invention has been completed by finding that the above object can be achieved. The particle size of the microcapsules containing the organic silver salt particles or the average particle size of the organic silver salt particles is 0.2 to 3.
It has been found that by setting the thickness to 0 μm, it is possible to obtain a recording material having the above-mentioned excellent properties and having a transparent recording layer. That is, in the recording material of the present invention, a recording layer containing at least a heat-responsive microcapsule containing organic silver salt or organic silver salt particles, a developer of organic silver salt, and a butadiene latex is provided on a support. It is a recording material. When an organic silver salt is included in a thermoresponsive microcapsule and used as a wall material of the thermoresponsive microcapsule, (1) a urethane modified product, (2) an allophanate modified product, (3) an isocyanurate modified product, ( 4)
Burette modified product, (5) carbodiimide modified product,
It is preferable to use at least one kind of isocyanate compound selected from (6) blocked isocyanate and (7) polymeric MDI to form a capsule wall from this reaction product. The addition amount of the isocyanate compound, which is the wall material of the thermoresponsive microcapsules, is preferably 0.1 to 5 in terms of solid weight ratio with respect to the organic silver salt. Further, by setting the average particle diameter of the thermoresponsive microcapsules to 0.2 to 3.0 μm, a recording material having a transparent recording layer can be obtained. In order to microcapsulate the organic silver salt, a dispersion liquid in which the organic silver salt is dispersed in an organic solvent is further added with the following formulas (a) to (k).
An oil phase component obtained by adding at least one polyvalent isocyanate compound represented by the formula (1) is added to an aqueous solution containing a water-soluble binder and then stirred to disperse the oil phase component in the aqueous solution. After being made into a liquid, the wall material of the thermoresponsive microcapsules is formed by the reaction between the isocyanate compound and water.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail. The organic silver salt contained in the recording layer of the recording material of the present invention is a colorless or white silver salt stable to light,
It produces silver by a redox reaction when heated with a developer regardless of the presence or absence of exposed silver halide. 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 an organic compound having an imino group, saccharin silver, silver phthalazinone, silver benzotriazole, etc. 2) Silver salt of an organic compound having a mercapto group or a 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. Among these, from the viewpoint of being white and stable to light, having excellent moisture resistance, being able to be used in combination with a reducing agent having a relatively weak reducing power, and having an excellent toning agent, , Silver behenate is most preferred. In the recording material of the present invention,
From the viewpoint of recording a high-concentration image using a high-concentration organic silver salt, it is preferable to use a desalted and refined organic silver salt. The desalting purification of the organic silver salt can be performed by the method described below.

In the present invention, the organic silver salt is preferably encapsulated in microcapsules 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 recording material. In the recording layer of the recording material of the present invention, a latent image is formed when exposed to light, and a reduction reaction with respect to an organic silver salt, that is, development of a photosensitive silver halide capable of causing rapid development is performed. When included adjacent to the salt, the recording material of the present invention becomes a light-sensitive material. In this case, silver halide is silver chloride, silver bromide,
It can be appropriately selected from known silver halides such as silver chlorobromide, silver iodide, silver iodobromide, silver chloroiodobromide and the like.

When the silver halide is contained adjacent to the organic silver salt, a silver halide forming agent is added to convert a part of the organic silver salt into silver halide as in the case of the dry silver. Alternatively, silver halide grains prepared by a known method may be mixed with the above organic silver salt. Examples of the silver halide forming agent include CaBr ₂ , KBr, and KC.
1, inorganic halogen compounds such as HBr, NH ₄ Br, NH
Onium halides such as ₄ Cl, halogenated carbon, N-
Examples thereof include halogen-donating compounds such as N-halides such as bromosuccinimide. When silver halide is used in combination, it is preferably encapsulated in a microcapsule together with an organic silver salt. When the photosensitive silver halide is not contained, the recording material of the present invention is a heat sensitive recording material.

The developing agent used in the present invention is a reducing agent having a function of reducing an organic silver salt to produce silver when heated, and has a rapid reducing reaction at a developing temperature.
It does not affect the color tone of the image after development,
And other characteristics are required. Examples of such reducing agents include hydroxycoumarone or hydroxycoumarans,
Sulfamidophenols or sulfoamidonaphthols, hydradones, hirooxamic acids, bis-β-naphthols, indane-1,3-diones, aminophenols or aminonaphthols, pyrazolin-5-ones, hydroxylamines , Reductones, hydrazines, hydroquinones, polyphenols such as bisphenol A, bisphenol B, gallic acid and gallic acid esters, phenylenediamines, hydroxyindanes, 1,4-dihydroxypyridines, amidoximes, hydroxy substitution Aliphatic carboxylic acid aryl hydrazides, N-hydroxyureas, phosphonamidophenols, phosphonamidoanilines, α-cyanophenylacetic acid esters, sulfonamideamilines and the like can be mentioned. Among them, it is preferable to use each compound represented by the following formula, octyl gallate, propyl gallate, ethyl gallate or methyl gallate.

[0011]

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In the present invention, from the viewpoint of accelerating the reduction reaction between the organic silver salt and the developer at the time of heating, adjusting the color tone of the image and carrying out rapid development, it is preferable to include a color tone agent in the recording layer. . 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 and reducing agent used, but the most common toning agent is at least 2
Heterocyclic organic compounds containing one heteroatom, wherein at least one nitrogen atom is present in the heterocycle. These are described, for example, in US Pat. No. 3,080,2.
No. 54 specification. Specific examples of such a toning agent include, for example, phthalazone (phthalazinone),
Anhydrous phthalates, 2-acetylphthalazinone, 2-phthalylphthalazinone, and substituted phthalazinones as described in JP-A No. 50-67132 are mentioned, and these are preferably used in the present invention. . Examples of other effective toning agents include pyrazolin-5-ones, cyclic imides, and quinazolinone as described in JP-A-46-6077. Specific examples of these include phthalimide, N-hydroxyphthalimide, and phthalimide silver. 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 present invention, the developer and the toning agent are used in a solid dispersion state or dissolved in a binder to be used in a uniform state, but separately from the organic silver salt and / or in the same capsule. The color tone agent may also be microencapsulated and used.

In the recording material of the present invention, it is preferable to take the following measures from the viewpoint of preventing heat fogging and stabilizing the background after image formation. First,
In addition, it is well known that the mercury compound has a remarkable effect on the prevention of thermal fogging and the stabilization of the background after the image formation. However, from the viewpoint of environmental pollution, it is not preferable to use them, and therefore, the present invention In JP-A-49-107.
24, 48-2842, and 48-8194, N-halogenosuccinimide, N-halogenoacetamide, N-halogenooxazolinone, N-halogenobenzotriazole, and It is preferred to use N-halogeno compounds such as N-halogenobenzimidazoles. Also, US Pat. No. 3,64
5,739, JP-A-49-125016, 49-130720, 50-57619, 50.
Higher fatty acids described in JP-A-39264, etc .; Tetrahalogenophthalic acid or its anhydride, aryl sulfonates such as benzene sulfonic acid, p-toluene sulfonic acid; Sulfinic acid or its salts; higher fatty acid lithium salts such as lithium myristate, lithium stearate, lithium behenate, lithium barmitate, and lithium laurate can be used as the acid stabilizer.

Other acid stabilizers include boric acid, salicylic acid, p-hydroxybenzoic acid, tetraprombenzoic acid,
Tetrachlorbenzoic acid, p-acetamidobenzoic acid, p
Alkyl-substituted benzoic acids such as -t-butylbenzoic acid, phthalic acid, isophthalic acid, trimellitic acid, pyromellitic acid, dicitric acid, 5 ', 5'-methylenebissalicylic acid 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,
Represented by groups such as aralkylsulfonyl, carboxyl, sulfo, and sulfamoyl), organic halogen compounds shown in US Pat. No. 4,465,761, and 2-trihalomethyl shown in US Pat. No. 4,452,885. An oxazole derivative, a heterocyclic compound having a trihalomethyl group shown in 4,756,999, and a compound disclosed in European Patent No. 622,666 are effective.

As a method for solid-dispersing the organic silver salt in the present invention, for example, an organic silver salt and a polymer binder such as polyvinyl alcohol, and, if necessary, a toning agent, an antifoggant, a dispersant, a solvent and the like are combined. , Ball mill, sand mill, etc. On the other hand, the reducing agent is similarly solid-dispersed or completely dissolved in an aqueous polymer binder solution such as polyvinyl alcohol. The respective liquids thus obtained are blended to prepare a solid dispersion, which is coated on a support to obtain a recording material. Further, the effect of the present invention is more remarkable when the above-mentioned heat fog preventive agent and photo tarnish preventive agent are used in combination with the heat responsive capsule.

The thermoresponsive microcapsule used in the present invention isolates the encapsulated substance at room temperature, and is not destroyed by pressure or heat during heating, and the wall of the microcapsule is permeable to the substance. It is a microcapsule.

The recording material of the present invention is characterized by using the following isocyanate compounds as the wall material of the thermoresponsive microcapsules. The isocyanate compound used here is a known isocyanate monomer (1) urethane modified product, (2) allophanate modified product,
(3) Isocyanurate modified product, (4) Burette modified product, (5) Carbodiimide modified product, (6) Blocked isocyanate modified product, and (7) Polymeric M
DI, a linear polymer of 4,4'-diphenylmethane diisocyanate (MDI).

As the isocyanate monomer forming the modified product, 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. 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 the reaction rate and improving the compounding ratio. 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. Further, when isocyanate is added, uretonimine is produced, and then 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, and examples of the blocking agent include phenol-based blocking agents such as phenol and xylenol, oximes, lactams and alcohols. Examples thereof include active hydrogen compounds. As the microcapsule wall material of the recording material of the present invention,
Specifically, from the viewpoint of safety and easy availability, the following formula (a)
The isocyanate compounds represented by (k) to (k) are mentioned.

[0021]

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[0022]

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As a method for producing microcapsules using such a wall material, a known production method can be adopted. In particular, for a core substance obtained by dissolving or dispersing an organic silver salt in an organic solvent, The oil phase component obtained by adding the wall material is emulsified in an aqueous solution in which a water-soluble polymer is dissolved, and then an interfacial polymerization method is used in which a wall made of a polymer of the wall material is formed around the oil droplets. Preferably. 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 and butyl acetate, toluene, xylene, phosphoric acid ester and the like.

It is preferable that the reactant for forming the polymer to be the wall from the wall material is heated after emulsification and dispersion. The heating condition is preferably 30 to 80 ° C. for 30 minutes to 4 hours, and if it is lower than 30 ° C., the reaction takes a long time and the reaction proceeds only incompletely. If the temperature exceeds ℃, it will be difficult to control the reaction.
Neither is preferred. Specific examples of the water-soluble polymer include gelatin, polyvinylpyrrolidone, and polyvinyl alcohol. For example, when an isocyanate compound is used as a capsule wall material, an oil phase component obtained by adding at least one isocyanate compound to a dispersion liquid obtained by dispersing an organic silver salt in the organic solvent as described above is used as gelatin or the like. After adding to the aqueous solution containing the water-soluble binder, the mixture is stirred to obtain a dispersion in which the oil phase component is dispersed in the aqueous solution, and the entire dispersion system is, for example, 40 to 90.
The wall material of the thermoresponsive microcapsule can be formed by heating to about ° C.

At this time, the average particle size of the resulting thermoresponsive microcapsules is preferably 0.1 to 3.0 μm, more preferably 0.2 to 1.2 μm.
By controlling the particle size within the above range, the transparency of the recording layer is improved, the image can be observed with transmitted light with the Schaukasten, and the transparency of the non-image area is excellent, so printing using ultraviolet light is performed. It has an advantage that it can be suitably used as a mask (light shielding layer of a printing photosensitive layer) when forming a plate. Further, in order to swell the microcapsule wall at the time of heating for forming the wall material of the microcapsule, the sensitizer may be added in an emulsified dispersion or solid dispersion state.

The sensitizer may be selected from among plasticizers of polymers used as microcapsule wall materials, and those having a melting point of 50 ° C. or higher, preferably 150 ° C. or lower and solid at room temperature. it can. For example, when the 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, or the like is preferably used.

Examples of the butadiene latex used in the present invention include butadiene, styrene, acrylonitrile, acrylic acid, acrylic acid esters, methacrylic acid, methacrylic acid esters, methyl methacrylate, ethyl methacrylate, vinyl acetate, ethylene, propylene. , Vinyl pyridine, vinyl chloride, acrylic acid, vinylidene chloride, vinyl alcohol, maleic acid,
Copolymers with one or more monomers having a double bond such as maleic acid ester, for example, styrene butadiene latex, acrylonitrile butadiene latex, and latex containing butadiene such as methyl methacrylate butadiene latex as a copolymerization component. Specific examples thereof include JP-A-60-97886 and JP-A-61-188.
184 to butadiene 20 to 80%, styrene 1
Copolymer of 0-75%, acrylic acid 5-30%, acrylonitrile 0-30%, olefin 0-65%, butadiene 15-55%, styrene 10-50%, methyl methacrylate 10-40%, acrylonitrile 15% There are the following copolymers: Also, JP-A-63-262281, JP-A-63-207687 and JP-A-61-280985.
Those described in etc. are also used. The butadiene latex used in the present invention preferably contains butadiene in an amount of 10 mol% or more, more preferably 20 mol% or more. Mere acrylic latex does not have the effect of the present invention.

The amount of the butadiene-based latex used is 0.1 to 5.0 g / m ² , preferably 0.6 to 3.0, in terms of solid state.
g / m ² . 0.03 parts to 1 part of organic silver salt
It is 1.25 parts, preferably 0.15 to 0.75 parts. In the present invention, a water-soluble binder may be used in combination with the butadiene latex. When used together, a recording material having less fog, higher color density and higher sensitivity, and less image glare than the water-soluble binder alone can be obtained.
The water-soluble binder used together in the present invention has a function of binding the developer and microcapsules contained in the recording layer and also of adhering the recording layer to the support. Examples of such water-soluble binders include gelatin and / or gelatin derivatives (eg, phthalated gelatin), polyvinyl alcohol, methyl cellulose, carboxymethyl cellulose, hydroxypropyl cellulose and other water-soluble polymers, arabic gum, polyvinylpyrrolidone,
Examples thereof include casein, styrene-butadiene latex, acrylonitrile-butadiene latex, polyvinyl acetate, polyacrylic acid ester, various emulsions of ethylene-vinyl acetate copolymer and the like. The amount of the water-soluble binder used is 0.5 to 5 g in terms of solid content.
/ M ² .

In addition to the above materials, citric acid, tartaric acid, oxalic acid, boric acid, phosphoric acid, pyrophosphoric acid and the like can be added as an acid stabilizer. As the recording material of the present invention, when a light-sensitive material is produced in an aqueous system, the general formula RCOOAg
The organic silver salt represented by the following is dispersed in water in which a water-soluble binder such as polyvinyl alcohol is dissolved, and then a halogen-donating compound is added to convert a part of the organic silver salt into silver halide. Alternatively, silver halide grains prepared by a known method may be mixed with the aqueous solid dispersion of the organic silver salt.

When the organic silver salt is encapsulated in microcapsules, the organic silver salt represented by the general formula RCOOAg is dispersed in an organic solvent, and then a halogen-donating compound is added to part of the RCOOAg. Simultaneously with or after conversion to silver halide, an oil phase component obtained by adding an isocyanate compound is added and stirred in an aqueous solution containing a water-soluble polymer to disperse the oil phase component, and then the isocyanate is added. A microcapsule solution containing microcapsules containing the above organic silver salt and silver halide is prepared by reacting a compound with water, and a developer for the organic silver salt is further added to prepare a coating solution for a recording layer. After that, it is preferably produced by coating the resulting coating liquid on a support and drying. Alternatively, the silver halide grains prepared by a known method may be dispersed in an organic solvent and mixed with an organic silver salt, and then the above microencapsulation operation may be performed.

When a heat-sensitive recording material is produced as the recording material of the present invention, it is not necessary to add a halogen-donating compound in the above case. The organic silver salt used in the present invention is preferably desalted and purified as described above. Desalination purification 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, the nitrate produced as a by-product by the addition of silver nitrate is used. It is to remove it out of 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 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. Examples of the transparent support include polyester films such as polyethylene terephthalate, polyethylene naphthalate and polybutylene terephthalate, cellulose derivative films such as cellulose triacetate film, polystyrene films, syndiotactic polystyrene films, polypropylene films and polyolefins such as polyethylene films. A film, a polyimide film, a polyvinyl chloride film, a polyvinylidene chloride film, a polyacrylic acid copolymer film, a polycarbonate film, and the like can be used, and these can be used alone or by laminating them, but especially heat treatment to a polyester film, Those subjected to antistatic treatment are preferable.

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. The thickness of the support is 20 to 300 μm, more preferably 50 to
The thickness is 250 μm, more preferably 60 to 150 μm. Below this range, the mechanical strength is insufficient and handling problems tend to occur. On the other hand, it is not necessary to increase the mechanical strength by increasing the thickness above this range. Films that can be used as the transparent support of the recording material of the present invention have a thickness of 20 to 300 μm.
A haze (cloudiness) of 3% or less at m is preferable.

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. The inorganic fine particles that can be used here include IA group, IIA group, IVA group, VIA group, VIIA group.
Group, VIII group, IB group, IIB group, IIIB group, IVB group, oxide of each element, hydroxide, sulfide, nitride, halide, carbonate, acetate, phosphate, phosphite, Examples thereof include organic carboxylates, silicates, titanates, borates and hydrous compounds thereof, complex compounds centering 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 VI element compounds such as molybdenum dioxide, molybdenum trioxide, molybdenum sulfide, etc., Group VIIA element compounds such as manganese chloride and manganese acetate, Group VIII element compounds such as cobalt chloride and cobalt acetate, cuprous iodide Group IB element compounds such as zinc oxide, zinc acetate, etc., Group IIIB element compounds such as aluminum oxide (alumina), aluminum oxide, aluminum fluoride, aluminosilicate (alumina silicate, kaolin, kaolinite) Examples thereof include particles of IVB group elements such as silicon oxide (silica, silica gel), graphite, carbon, graphite, and glass, and natural mineral particles such as carnal stone, kainite, mica (mica, quinnemo), and birose ore. Among them, silica, talc, titania, alumina, calcium carbonate, calcium oxide, calcium chloride and the like, and mixtures thereof are preferable from the viewpoint of handleability. 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 a paper laminated with this is used as a support, or when a transparent support is used, these are used in order to enhance the adhesiveness between the support and the recording layer. It is preferable to provide an undercoat layer between the two. As a material for the undercoat layer, gelatin, synthetic polymer latex, nitrocellulose, or the like is used. The coating amount of the undercoat layer is 0.1 g / m ^{2 to} 2.0 g / m ^2.
Is preferably in the range of 0.2 g / m ² to
A range of 1.0 g / m ² is preferred. The undercoat layer may be swollen by water contained in the recording layer when the recording layer is coated thereon, and may deteriorate the image quality of the recording layer. Therefore, it is desirable to cure the undercoat layer with a hardening agent. .

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, before applying the undercoat layer, it is desirable to activate the surface of the support by a known method. 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. 2,84
No. 6,727, No. 3,549,406, No. 3,5
The corona discharge treatment described in No. 90,107 and the like is most preferably used. In the present invention, a protective layer containing a pigment is preferably provided on the recording layer in order to protect the recording layer from sticking, solvents and the like.

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 preferably contains, as a binder, fully aged polyvinyl alcohol, carboxy-modified polyvinyl alcohol, silica-modified polyvinyl alcohol and the like from the viewpoint of retaining the pigment and improving transparency. The coating solution for protective layer in the present invention (referred to as protective layer solution) is obtained by mixing a pigment with the solution of the above-mentioned binder. Depending on the purpose, a lubricant such as zinc stearate, calcium stearate, paraffin wax, polyethylene wax, etc. And dispersant, optical brightener,
You may further add various auxiliary agents, such as a crosslinking agent, a sulfosuccinic-acid type alkali metal salt, and a fluorine-containing surfactant.

The recording material of the present invention comprises, for example, a recording layer coating solution and a protective layer coating solution containing thermoresponsive microcapsules containing an organic silver salt, a developer, a water-soluble binder, and other additives. Preparation, coating and drying on a support by a coating method such as bar coating, blade coating, air knife coating, gravure coating, roll coating coating, spray coating, dip coating, etc., and the solid content is 2.5 to 25 g / m 2.
No. ² recording layer and a protective layer having a solid content of 0.2 to 7 g / m ² are provided. The coating amount of the organic silver salt and the developer is 0.5 to 3.0 as the Ag component in the recording layer.
g / m ² is preferable, and 0.8 to 2.0 g is particularly preferable.
/ M ² . In the coating liquid used in the present invention, a pigment dispersant, a thickener, a flow modifier, an antifoaming agent, a foam suppressor, a release agent, a colorant and the like may be added, if necessary, unless the characteristics of the present invention are impaired. It can be blended appropriately.

Further, if necessary, a back coat layer may be provided on the surface of the support of the recording material opposite to the color developing layer.
As the back coat layer, any one known as a back coat layer of a recording material can be used.

[0040]

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 of water.
g, and after heating to 90 ° C, 45 g of water was added to NaOH.
After adding 3.0 g of an aqueous solution and stirring well,
Cooled to 50 ° C. Then, to the resulting solution, 75 g of water
An aqueous solution containing 12.9 g of AgNO ₃ added thereto was added dropwise over 5 minutes, and the reaction was carried out by continuing stirring for 30 minutes. The obtained reaction liquid was filtered with a filter cloth, 800 ml of water was added, and the mixture was stirred, washed, and then filtered again. After repeating such a washing operation three times, the obtained solid was dried with a blow dryer at 50 ° C. for 3 days to obtain a silver behenate dried solid.

(Preparation of Capsule Solution Encapsulating Silver Behenate) 27 g of the dried silver behenate solid was weighed,
To this, 1.10 g of polyvinyl butyral and 110 g of isoamyl acetate were added, dispersed with a paint shaker for 3 hours, and further dispersed with a motor mill to obtain a silver behenate dispersion having an average particle size of 0.4 μm. Takenate D-110N as a capsule wall material in 10 g of the obtained dispersion liquid.
[Brand name, manufactured by Takeda Pharmaceutical Co., Ltd .: Isocyanate compound having the structure of the formula (a)] 6 g was added as an oil phase component. Add this to 10% polyvinyl alcohol (PVA
217E: trade name, manufactured by Kuraray Co., Ltd.) 32 g of aqueous solution and 8 parts of water
0 g was added to the mixed solution (aqueous phase), and a homogenizer (manufactured by Nippon Seiki Co., Ltd., Ace Homogenizer) was used.
Microemulsified at 000 rpm for a further 10 minutes. The obtained fine emulsified dispersion was heated to 65 ° C. while stirring, and kept for 3 hours to perform an encapsulation reaction. Here, the solid content weight ratio of the wall material to silver behenate was about 2.7.
The obtained liquid has an average particle size of 0.8 including silver behenate.
μm microcapsule solution.

(Preparation of Developer Dispersion) To 33 g of 15% polyvinyl alcohol (PVA205, manufactured by Kuraray Co., Ltd.), 10 g of phthalazinone (color tone agent), 5 g of methyl gallate and 5 g of n-propyl gallate were added, and a magnetic ball mill was used to obtain 24.
The dispersion was carried out for a time to prepare a developer dispersion having a particle size of 0.4 μm.

(Preparation of coating solution for heat-sensitive recording layer) 15 g of the above-mentioned capsule solution containing silver behenate was mixed with 4 g of water, 0.6 g of a 3% benzotriazole methanol solution and 2.8 g of a developer dispersion liquid, and further mixed. Styrene Butadiene Latex (Sumitomo Nogatac Co., Ltd., trade name SN307,
2.0 g of solid content 48%) was mixed to obtain a coating solution.

(Preparation of coating liquid for protective layer) 32 g of water and carboxy-modified polyvinyl alcohol (PVA-KL-3)
18: trade name, manufactured by Kuraray Co., Ltd.) 32 g of 10% aqueous solution,
Epoxy-modified polyamide (FL-71: trade name, manufactured by Toho Kagaku Co., Ltd.) 3% dispersion liquid 3 g, mixed with polyoxyethylene (surfactant) 2% aqueous solution 5 g, zinc stearate 20% dispersion liquid (Hydrin Z: trade name, manufactured by Chukyo Yushi Co., Ltd.) was added to obtain a coating liquid for protective layer.

(Preparation of recording material) Transparent polyethylene terephthalate support provided with an undercoat layer (130 μm / thickness)
The recording layer coating solution was coated on the above using a wire bar so that the dry film thickness was 25 g / m ^2, and dried at 50 ° C. for 20 minutes. Then, a coating material for a 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 recording material.

Thermal recording and evaluation of image glare Using the recording material thus obtained, thermal recording was carried out as follows. A thermal head KST type (trade name: manufactured by Kyocera Corporation) was used for the obtained recording material, and the applied voltage and the pulse width were adjusted so that the recording heat energy per unit area was 60 mJ / mm ² . An image was recorded, and the optical transmission densities of the maximum color-developed part and the background part (minimum color-developed part) were measured using a Macbeth densitometer. The glare of the image was visually evaluated, and those without glare were indicated by ◯, and those with glare were indicated by x. In addition, the transparency of the background portion was measured using a haze meter. The smaller the haze value, the higher the transparency. The results are shown in Table 1.

Example 2 Instead of Takenate D-110N (capsule wall agent) used in the capsule liquid containing silver behenate of Example 1, Vernock DN990S (isocyanate-based compound represented by the above formula (g)) was used. Compound: manufactured by Dainippon Ink and Chemicals, Inc., and the average particle size of the capsules is 0.1.
Using a 5 μm emulsion dispersion, styrene-acrylonitrile-butadiene latex (SNX4831 manufactured by Sumitomo Nogatac Co., Ltd.) was used as a butadiene-based latex.
A recording material of Example 2 was obtained in the same manner as in Example 1 except that 2.0 g of solid content 48%) was used.

Example 3 (Preparation of Silver Behenate / Phtalazone Co-Dispersion Liquid) 21.1 g of the silver behenate dry solid obtained in Example 1 was weighed, and 3.26 g of phthalazone and 15% polyvinyl alcohol were added thereto. An aqueous solution (PVA205, manufactured by Kuraray Co., Ltd.) 52.8 g and ion-exchanged water 103 g were added and dispersed for 3 hours with a paint shaker to obtain a silver behenate / phthalazone dispersion having an average particle size of 0.6 μm or less.

(Preparation of developer aqueous solution) 22% polyvinyl alcohol (PVA203, Kuraray Co., Ltd.) 50.0
4.5 g of methyl gallate and 35.0 g of deionized water
Was added, and the mixture was stirred at 60 ° C. for 1 hour to prepare a developer aqueous solution.

(Preparation of coating liquid for heat-sensitive recording layer) 8.0 g of the above-mentioned silver behenate / phthalazone co-dispersion liquid, 4.0 g of the developer aqueous solution, 1.9 g of a 3% benzotriazole methanol solution and SBR latex ( Sumitomo Nogatac Co., Ltd., trade name SN307, solid content 48%) 1.
2 g was added and mixed by stirring to obtain a coating liquid for heat-sensitive recording layer.

(Preparation of Thermosensitive Recording Material) The recording material of Example 3 was processed in the same manner as in Example 1 except that the above-mentioned coating liquid for the thermal recording layer was applied so that the dry film thickness was 10 g / m ^2. Got

[Comparative Example 1] The same procedure as in Example 1 was carried out except that an aqueous solution of PVA205 was added so as to have the same amount in terms of solid content instead of the SBR latex added to the coating liquid for the thermal recording layer in Example 1. Then, a recording material of Comparative Example 1 was obtained.

[Comparative Example 2] The same treatment as in Example 3 was carried out except that an aqueous solution of PVA205 was added so as to have the same amount in terms of solid content, instead of the SBR latex added to the coating liquid for the thermosensitive recording layer in Example 3. Then, a recording material of Comparative Example 2 was obtained. These recording materials were evaluated in the same manner as in Example 1 and the results shown in Table 1 were obtained.

[0055]

[Table 1]

[0056]

As described above, according to the present invention, it is possible to obtain a recording material with less fog and a higher density of a recorded image as compared with the conventional one, and further, there is an effect that there is no glaze glare. Further, by controlling the particle size of the organic silver salt or the particle size of the microcapsules of the recording material of the present invention, a recording material having excellent transparency can be obtained.

Claims (4)

[Claims] 1. A recording material comprising a support and a recording layer containing at least an organic silver salt and a developer of the organic silver salt, the butadiene latex containing butadiene as a polymerization component in the recording layer. A recording material characterized by containing. 2. The recording material according to claim 1, wherein the butadiene-based latex contains 3 to 125% by weight of an organic silver salt. 3. The recording material according to claim 1, wherein the organic silver salt is encapsulated in thermoresponsive microcapsules. 4. The recording material according to claim 1, 2 or 3, wherein the average particle diameter of the organic silver salt particles or the microcapsules containing the organic silver salt is 0.2 to 3.0 μm. .