JPH05318909A - Thermal recording material - Google Patents

Abstract

PURPOSE:To provide a thermal recording material having an almost white background and capable of forming an image by exposure due to infrared laser beam and thermal development. CONSTITUTION:In a thermal recording material for infrared laser recording obtained by coating a support with a coating solution of a photo-setting compsn. containing at least a microcapsule containing an electron donating leuco dye, an electron acceptive compd. having a polymerizable group and a photopolymerization initiator and drying the coating layer, the photopolymerization initiator is a near infrared absorbable polymerization initiator having photosensitivity within a wavelength region of 600nm or more.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat-sensitive recording material, and more particularly to a heat-sensitive recording material for recording using an infrared laser beam.

[0002]

2. Description of the Related Art A thermal recording system in which a thermal head is brought into close contact with the surface of a thermosensitive recording material having a thermosensitive coloring layer provided on a support to scan, and heat energy is transferred to the thermosensitive coloring layer directly or through a protective layer to record a color image. Is widely known and is applied to facsimiles, 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 become dust on the surface of the thermal head. In some cases, the recording image may not be correctly obtained due to the adhesion, and the thermal head may be damaged.

Further, the thermal recording system 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 is a drawback that there is a limit to high speed recording, high density recording and high image quality recording.

In order to solve the above problems of the thermal recording system using a thermal head, a visible image is formed by uniformly heating and developing after photoexposure using a photopolymerizable composition and a thermosensitive coloring material. The method is known. This is achieved by a combination of microcapsules containing an electron-donating colorless dye and an electron-accepting compound having a polymerizable ethylene group, and a photopolymerization initiator. Most of the photopolymerization initiators used in these systems are photosensitive at 450 nm or less. On the other hand, with the recent remarkable progress of laser technology, various recording such as resist patterning and plate making is performed by using laser light, especially inexpensive and small semiconductor laser light. Is required. However, since this semiconductor laser light does not fall below 600 nm, the conventional photopolymerization initiator cannot be exposed.

Recently, however, it has been reported that a compound composed of a cyanine dye having a maximum absorption in the near infrared region and an organic boron generates a radical with light absorption to polymerize and cure the monomer. Research on infrared absorbing polymerization initiators has been actively conducted.

The inventors of the present invention have made earnest studies to obtain a high-quality heat-sensitive recording material which is capable of non-contact recording and has a white background close to white. As a result, at least an electron-donating colorless dye is formed on a support. A recording material provided by coating and drying a coating solution containing a photocurable composition containing an electron-accepting compound having a polymerizable group and a photopolymerization initiator, the microcapsule containing It was found that a near-infrared absorbing polymerization initiator having a photosensitivity of 600 nm or more can be used for photoexposure by an infrared laser beam, and then a good image can be obtained by heating the entire surface.

Therefore, an object of the present invention is to provide a heat-sensitive recording material capable of recording a good image with a high quality by a laser beam.

[0009]

The above-mentioned objects of the present invention include, on a support, microcapsules containing at least an electron-donating colorless dye, and an electron-accepting compound having a polymerizable group and a photopolymerization initiator. A recording material provided by coating and drying a coating liquid containing a photocurable composition, wherein the photopolymerization initiator is a near-infrared absorbing polymerization initiator having photosensitivity at 600 nm or more. Achieved by a thermal recording material for infrared laser recording.

The electron-donating colorless dyes according to the present invention include triphenylmethanephthalide compounds, fluorane compounds, phenothiazine compounds, indolylphthalide compounds, leuco-olamine compounds, rhodamine-lactam compounds, and tri- compounds. There are various compounds such as phenylmethane compounds, triazene compounds, spiropyran compounds, and fluorene compounds. Specific examples of the phthalides include US Reissue Patent Specification No. 23024 and US Patent Specification No. 34.
No. 9111, No. 3491112, No. 349111
No. 6 and No. 3509174, and specific examples of fluoranes are described in US Pat. No. 3,624,107 and No. 36277.
No. 87, No. 3641011, No. 3462828,
No. 3681390, No. 3920510, No. 3
No. 959571, specific examples of spiropyrans are US Pat. No. 3,971,808, and pyridine compounds and pyrazine compounds are US Pat. No. 3,775,424, No. 38.
No. 53869, No. 4246318, fluorene compounds and the like.

The electron-accepting compound having a polymerizable group in the present invention is not particularly limited as long as it is a monomer having an electron-accepting group and an ethylenically unsaturated bond in one molecule.

The electron-accepting compound having a polymerizable group used in the present invention is a methacryloxyethyl ester of benzoic acid having a hydroxy group (JP-A-63-173682).
No.), acryloxyethyl ethyl ester, an ester of benzoic acid having a hydroxy group and hydroxymethylstyrene (JP-A-59-83693, JP-A-60-14).
1587 and JP-A-62-99190), hydroxystyrene (European Patent No. 29323), zinc halide N-vinylimidazole complexes and JP-A-63-3175.
No. 58, Japanese Patent Application No. 2-15
No. 6381, 3-halo-4-hydroxybenzoic acid ester, Japanese Patent Application No. 2-150319, resorcinic acid ester derivative, Japanese Patent Application No. 3-333774, polymerizable phenol derivative, Japanese Patent Application No. 4-30961. Examples thereof include sulfonylphenol derivatives.

Specific examples of the electron-accepting compound having a polymerizable group include 4-hydroxybenzoic acid- (2
-Methacryloyloxyethyl) ester, 2,4-dihydroxybenzoic acid- (2-methacryloyloxyethyl) ester, 2,4-dihydroxybenzoic acid vinylbenzyl ester, 2,4-dihydroxybenzoic acid- (3
-Methacryloyloxypropyl) ester, 2,4-
Dihydroxybenzoic acid- (4-methacryloyloxybutyl) ester, 2,4-dihydroxybenzoic acid- (6
-Methacryloyloxyhexyl) ester, 2,4-
Dihydroxy-6-methylbenzoic acid vinylbenzyl ester, β-methacryloyloxyethoxysalicylic acid and its zinc salt, 3-chloro-4-hydroxybenzoic acid-
(2-methacryloyloxyethyl) ester, 3-chloro-4-hydroxybenzoic acid vinylphenethyl ester, 3-chloro-4-hydroxybenzoic acid- (2-acryloyloxyethyl) ester, 3-chloro-4-hydroxybenzoic acid -(3-methacryloyloxypropyl) ester, 3-chloro-4-hydroxybenzoic acid-
(3-Acryloyloxypropyl) ester, 3-chloro-4-hydroxybenzoic acid- (4-methacryloyloxybutyl) ester, 3-chloro-4-hydroxybenzoic acid- (6-methacryloyloxyhexyl) ester, 3-chloro -4-Hydroxybenzoic acid- (6-acryloyloxyhexyl) ester, 3-fluoro-4
-Hydroxybenzoic acid- (6-methacryloyloxyhexyl) ester, 3-chloro-4-hydroxybenzoic acid- [2- (2-methacryloyloxyethoxy) ethyl] ester, 3-chloro-4-hydroxybenzoic acid-
"2- [4- (β-methacryloyloxyethoxy) phenoxy] ethyl" ester, 2-chloro-4- [2-
(Β-methacryloyloxyethoxy) ethylsulfonyl] phenol, 2-chloro-4- (6-methacryloyloxyhexylsulfonyl) phenol, 2-chloro-4- (8-methacryloyloxyoctylsulfonyl) phenol;

Β-methacryloxyethyl orserinate, β-acryloxyethyl orserinate; methacryloxymethylphenol, acryloxymethylphenol, β-methacryloxyethoxyphenol, β-acryloxyethoxyphenol, β-hydroxyethoxycarbonyl Phenol, 3-β-hydroxyethoxyphenol, 3,5-distyrenesulfonic acid amidophenol, β-methacryloxyethyl-β-resorcinate, β-acryloxyethyl-β-resorcinate,
β'-methacryloxyethyl-β-resorcinate; hydroxystyrene sulfonic acid-N-ethylamide, β-
Methacryloxypropyl-p-hydroxybenzoate, β-acryloxypropyl-p-hydroxybenzoate, β-methacryloxyethyl-p-hydroxybenzoate; β-methacryloxyethoxy-dihydroxybenzene, β-methacryloxyethyl-p-hydroxycinna Mate, β-acryloxyethyl-p-hydroxycinnamate;

Methacrylamide amidopropanesulfonic acid, acrylamidopropanesulfonic acid, vinylbenzyloxyphthalic acid, methacryloxyethoxyphthalic acid, acryloxyethoxyphthalic acid, methacrylic acid, acrylic acid,
Methacryloxyethoxyhydroxynaphthoic acid, acryloxyethoxyhydroxynaphthoic acid, γ-styrenesulfonyloxy-β-methacryloxypropanecarboxylic acid, vinyloxyethyloxybenzoic acid, β-methacryloxyethyloxycarbonylhydroxybenzoic acid, β-
Acryloxyethyloxycarbonylhydroxybenzoic acid, styrenesulfonylaminosalicylic acid, β-methacryloxyethoxysalicylic acid, β-acryloxyethoxysalicylic acid, γ-acryloxypropyl-α-hydroxyethyloxysalicylic acid, N, N'-di-β- Methacryloxyethylaminosalicylic acid, N, N'-di-β
-Acryloxyethylaminosalicylic acid, N, N'-di-β-methacryloxyethylaminosulfonylsalicylic acid, N, N'-di-acryloxyethylaminosulfonylsalicylic acid and the like, and metal salts thereof such as zinc metal salts You can

The polymerization initiator which is used in the present invention and which is sensitive to light having a wavelength of 600 nm or more (laser light) has a low absorption of light in the visible light region and a particularly high absorption of the wavelength of light in the infrared region. Complexes consisting of cationic dyes and organic borons are preferred.

The above-mentioned dyes include cyanine dyes, phthalocyanine dyes, pyrylium / thiopyrylium dyes, azulenium dyes, squarylium dyes, and N dyes.
Metal complex salt dyes such as i and Cr, naphthoquinone dyes / anthraquinone dyes, indophenol dyes, indoaniline dyes, triphenylmethane dyes, triallylmethane dyes, aminium dyes, diimmonium dyes, and nitroso compounds be able to. Among these, it is preferable to use one having a high absorption rate of light in the near-infrared region having a wavelength of 700 nm to 900 nm from the viewpoint of practical use of a semiconductor laser that oscillates near-infrared light. Specific examples thereof include dyes represented by the following formula.

[0018] (1) cyanine _{dyes: (CH 3) 2 N- (} CH = CH) 5 -CH = + N (CH 3) 2 ClO 4 -,

[Chemical 1] (However, n is 2 or 3),

[0019]

[Chemical 2] (However, R is a hydrogen atom or N (CH ₃ ) ₂ , N (CH
₂ CH _{3) 2,} R 'is _{N (CH 3) 2, N} (CH 2 CH
₃ ) ₂ ), A- (CH = CH) _n -CH = B where A is a group represented by the following formula:

[0020]

[Chemical 3]

[0021]

[Chemical 4]

[0022]

[Chemical 5]

[0023]

[Chemical 6]

[0024]

[Chemical 7]

[0025]

[Chemical 8] B is a group represented by the following formula,

[0026]

[Chemical 9]

[0027]

[Chemical 10]

[0028]

[Chemical 11]

[0029]

[Chemical formula 12]

[0030]

[Chemical 13]

[0031]

[Chemical 14] R is an alkyl group, X is a counterion, and in some cases,
A chlorine atom, an alkyl group, an alkoxy group or an aryl group may be present in the benzene ring or the naphthalene ring. n is an integer of 0-3.

[0032]

[Chemical 15] (However, R is an alkyl group and X is a halogen atom),

[0033]

[Chemical 16] (However, R is a substituted or unsubstituted alkyl group, an alkoxy group, an alkenyl group, X is a hydrogen atom or a halogen atom, Y is a halogen, perchlorate, a substituted or unsubstituted benzene sulfonate, paratoluene sulfonate, Methylsulfate, ethylsulfate, benzenecarboxylate, methylcarboxylate or trifluoromethylcarboxylate, n being 0 to
Is an integer of 3),

[0034]

[Chemical 17] (However, R ¹ , R ² and R ³ are each a substituted or unsubstituted alkyl group and may be the same or different, and X ⁻ is a perhalogenate ion, a toluenesulfonate ion or an organic group. Is a boron ion, and n is 0 to
It is an integer of 3. A halogen atom is present in at least one of the 4-position, 5-position, 6-position and 7-position of the indolenine ring, and in some cases, a halogen atom may be further present in another position. In some cases, the benzene ring has an alkyl group,
Alkoxy group, hydroxy group, allyl group or alkali carbonyl group may be substituted),

[0035]

[Chemical 18](However, A¹And A²Are hydrogen atom or substitution
Group, Z is an atomic group necessary for forming a five-membered heterocycle, R
¹~ R^FourEach is a hydrogen atom or a substituent, R ^FiveIs
Even if it is a substituent, it may form a 6-membered heterocycle with Z.
X^-Is an anion, and n is an integer of 0 to 2.
),

[Chemical 19]

[0036]

[Chemical 20] Chemical formula Φ-L = Ψ (X ⁻ ) _m (where Φ and Ψ are indole ring residue, thiazole ring residue, oxazole ring residue, selenazole ring residue, imidazole, each of which may have an aromatic ring fused thereto) A ring residue or a pyridine ring residue, L is a linking group for forming monocarbocyanine, dicarbocyanine, tricarbocyanine or tetracarbocyanine, and m is 0 or 1.)

(2) Squarium dye:

[Chemical 21]

[0038]

[Chemical formula 22]

(3) Azurenium dye:

[Chemical formula 23] (However, R ¹ and R ² , R ² and R ³ , R ³ and R ⁴ , R ⁴
And R ⁵ and R ⁵ and R ⁶ and R ⁶ and R ⁷ form at least one combination to form a ring with a substituted or unsubstituted heterocycle or an aliphatic ring, and R ¹ when not forming the ring. , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ and R ⁷ are each a hydrogen atom, a halogen atom or a monovalent organic residue, and are R ¹ and R ² , R ² and R ³ , R ³ and R ⁴ , R ⁴ and R
^A substituted or unsubstituted aromatic ring may be formed by a combination of at least one of ⁵ , R ⁵ and R ⁶ and R ⁶ and R ⁷ . A is a divalent organic residue linked by a double bond, and Z ^- is an anion residue. Note that at least one carbon atom forming the azulene ring may be replaced with a nitrogen atom to form an azaazulene ring).

(4) Indophenol dye:

[Chemical formula 24] (However, X and Y are a hydrogen atom, an alkyl group,
An acylamino group, an alkoxy group or a halogen atom, R ¹ , R ² and R ³ are each a hydrogen atom, C _{1 to} C
₂₀ substituted or unsubstituted alkyl group, aryl group, heterocycle or cyclohexyl group, A is -NHCO- or-
CONH-).

(5) Metal complex salt type dye:

[Chemical 25] (However, R ^{1 to} R ⁴ are each an alkyl group or an aryl group, and M is a divalent transition metal atom),

[0042]

[Chemical formula 26] (However, R ¹ and R ² are each an alkyl group or a halogen atom, and M is a divalent transition metal atom),

[0043]

[Chemical 27] (However, R ¹ and R ² are each a substituted or unsubstituted alkyl group or aryl group, and R ³ is an alkyl group, a halogen atom or a —N (R ⁴ ) —R ⁵ group (herein, R ⁴ and R ⁵ is a substituted or unsubstituted alkyl group or aryl group), M is a transition metal atom, and n is 0 to 3
Is an integer),

[0044]

[Chemical 28] (However, [Cat] is a cation necessary for neutralizing the complex salt, M is Ni, Cu, Co, Pd or Pt, and n is 1 or 2.)

[0045]

[Chemical 29] (However, [Cat] is a cation necessary for neutralizing the complex salt, M is Ni, Cu, Co, Pd or Pt, and n is 1 or 2.)

[0046]

[Chemical 30] (However, X is a hydrogen atom, a bromine atom, or a methyl group, n is an integer of 1 to 4, and A is a quaternary ammonium group),

[0047]

[Chemical 31](However, X¹And X²Are nitro groups and / or
A halogen atom, n ¹And n²Are 1 to 3 respectively
Integer, R¹And R²Are amino group and monoalkyl, respectively
Amino group, dialkylamino group, acetylamino group,
Nzoylamino group (including substituted benzoylamino group)
Yes, X¹And X², N₁And n₂And R¹And R²Is that
May be the same as or different from each other, and M is Cr
Or Co atom and Y is hydrogen, sodium, or potassium
Ammonium, aliphatic ammonium (substituted aliphatic ammonium
(Including ammonium) or alicyclic ammonium).

(6) Naphthoquinone type and anthraquinone type dyes:

[Chemical 32] (However, R is a hydrogen atom, an alkyl group, an allyl group, an amino group or a substituted amino group),

[0049]

[Chemical 33] (However, R is a hydrogen atom, an alkyl group, an allyl group, an amino group or a substituted amino group),

[0050]

[Chemical 34] (However, R is a hydrogen atom, an alkyl group, an allyl group or a substituted amino group),

[0051]

[Chemical 35] (However, X is a halogen atom.),

[0052]

[Chemical 36] (However, X is a halogen atom),

[0053]

[Chemical 37] Among these dyes, the cyanine dyes are particularly preferably used in the heat-sensitive recording material of the present invention. These dyes may be used alone or in combination of two or more.

The electron-donating colorless dye used in the present invention has a viewpoint of improving the transparency of the heat-sensitive layer, a viewpoint of raw storability such as preventing contact with an electron-accepting compound at room temperature (prevention of fog), and a coloring sensitivity. From the viewpoint of controlling, etc., the electron-donating colorless dye is encapsulated and used.

Any of an interfacial polymerization method, an internal polymerization method, and an external polymerization method can be adopted for producing the microcapsules used in the present invention. Particularly, a core substance containing an electron-donating colorless dye or the like is used. It is preferable to employ an emulsion polymerization method in which after emulsifying the water-soluble polymer in an aqueous solution in which the water-soluble polymer is dissolved, a wall of the polymer substance is formed around the oil droplets.

The reactant forming the polymer substance is added inside the oil droplet and / or outside the oil droplet. Specific examples of the polymer substance include polyurethane, polyurea, polyamide, polyester, polycarbonate, urea-formaldehyde resin, melamine resin, polystyrene, styrene methacrylate copolymer, styrene-acrylate copolymer and the like. Preferred polymeric substances are polyurethanes, polyureas, polyamides, polyesters and polycarbonates, particularly preferably polyurethanes and polyureas. Two or more polymer substances can be used in combination. Specific examples of the water-soluble polymer include gelatin, polyvinylpyrrolidone, polyvinyl alcohol and the like.

For example, when polyurea is used as the capsule wall material, polyisocyanates such as diisocyanate, triisocyanate, tetraisocyanate and polyisocyanate prepolymer, polyamines such as diamine, triamine and tetraamine, and amino groups are used. The microcapsule wall can be easily formed by reacting a prepolymer containing two or more of the above, piperazine or a derivative thereof, a polyol and the like by an interfacial polymerization method in an aqueous solvent.

For example, the composite wall made of polyurea and polyamide or the composite wall made of polyurethane and polyamide is added, for example, by using polyisocyanate and acid chloride or polyamine and polyol after adjusting the pH of the emulsifying medium to be the reaction solution. It can be prepared by warming. Details of the method for producing a composite wall composed of these polyurea and polyamide are described in JP-A-58-6.
No. 6948.

In the present invention, the electron-accepting compound having a polymerizable group and the near-infrared absorbing polymerization initiator are dissolved in a water-insoluble or insoluble organic solvent, and then this is mixed with a surfactant. It is used by mixing with an aqueous phase having a water-soluble polymer as a protective colloid and emulsifying and dispersing it.

The organic solvent used in this case can be appropriately selected from high boiling point oils. Among them, preferable oils include dimethylnaphthalene, diethylnaphthalene, diisopropylnaphthalene, dimethylbiphenyl, diethylbiphenyl, diisopropylbiphenyl, diisobutylbiphenyl, 1-methyl-1-dimethylphenyl-1-phenylmethane, 1 in addition to esters.
-Ethyl-1-dimethylphenyl-1-phenylmethane, 1-propyl-1-dimethylphenyl-1-phenylmethane, triallylmethane (eg, tritoluylmethane, toluyldiphenylmethane), terphenyl compound (eg, terphenyl) , Alkyl compounds (eg terphenyl), alkylated diphenyl ethers (eg propyldiphenyl ether), hydrogenated terphenyls (eg hexahydroterphenyl), diphenyl ethers and the like. Among these, it is particularly preferable to use esters from the viewpoint of emulsion stability of the emulsified dispersion.

Examples of the esters include phosphates (eg, triphenyl phosphate, tricresyl phosphate, butyl phosphate, octyl phosphate, cresyl diphenyl phosphate), phthalates (dibutyl phthalate, 2-ethylhexyl phthalate, phthalic acid). Ethyl, octyl phthalate, butylbenzyl phthalate) dioctyl tetrahydrophthalate,
Benzoic acid ester (ethyl benzoate, propyl benzoate, butyl benzoate, isopentyl benzoate, benzyl benzoate), abietic acid ester (ethyl abietic acid, benzyl abietic acid), dioctyl adipate,
Isodecyl succinate, dioctyl azelate, oxalate (dibutyl oxalate, dipentyl oxalate), diethyl malonate, maleate (dimethyl maleate, diethyl maleate, dibutyl maleate), tributyl citrate, sorbate ( Methyl sorbate, ethyl sorbate, butyl sorbate), sebacic acid ester (dibutyl sebacate, dioctyl sebacate), ethylene glycol esters (formic acid monoester and diester, butyric acid monoester and diester, lauric acid monoester and diester, Palmitic acid monoesters and diesters, stearic acid monoesters and diesters, oleic acid monoesters and diesters), triacetin, diethyl carbonate, diphenyl carbonate, ethyl carbonate. Emissions, propylene carbonate,
Examples thereof include boric acid esters (tributyl borate, tripentyl borate) and the like. Among these, the use of tricresyl phosphate alone or in combination is preferable because the emulsion dispersion stability of the electron-accepting compound is particularly good. It is also possible to use the above oils in combination, or to use in combination with other oils.

In the present invention, an auxiliary solvent may be added to the above organic solvent as a dissolution aid having a low boiling point. As such an auxiliary solvent, for example, ethyl acetate, isopropyl acetate, butyl acetate, methylene chloride and the like can be mentioned as particularly preferable ones.

The water-soluble polymer to be contained as a protective colloid in the aqueous phase mixed with the oil phase containing these components is appropriately selected from known anionic polymers, nonionic polymers and amphoteric polymers. However, polyvinyl alcohol, gelatin, cellulose derivatives and the like are preferable.

As the surface active agent to be contained in the aqueous phase, an anionic or nonionic surface active agent which does not cause precipitation or aggregation by acting on the protective colloid may be appropriately selected and used. it can. Preferred surfactants include sodium alkylbenzene sulfonate, sodium alkylsulfate, dioctyl sodium sulfosuccinate, polyalkylene glycol (for example, polyoxyethylene nonylphenyl ether), and the like.

In the emulsified dispersion of the present invention, an oil phase containing the above components and an aqueous phase containing a protective colloid and a surfactant are used by means such as high speed stirring and ultrasonic dispersion, which are commonly used for fine particle emulsification. Then, they can be mixed and dispersed to obtain easily.

The value of the ratio of the oil phase to the water phase (weight of oil phase / weight of water phase) is preferably 0.02 to 0.6, and particularly preferably 0.1 to 0.4. When it is 0.02 or less, the amount of the water phase is too large to be diluted and sufficient color development cannot be obtained.
On the other hand, when it is 0.6 or more, the viscosity of the liquid becomes high, which causes inconvenience in handling and a decrease in coating liquid stability.

When the heat-sensitive layer liquid prepared as described above is coated on the support, known coating means using a water-based or organic solvent-based coating liquid is used. In this case, in order to safely and uniformly apply the heat-sensitive layer liquid and maintain the strength of the coating film, in the present invention, methyl cellulose, carboxymethyl cellulose, hydroxyethyl cellulose, starches, gelatin, polyvinyl alcohol, carboxy modified polyvinyl alcohol, Polyacrylamide, polystyrene and its copolymers, polyester and its copolymers, polyethylene and its copolymers, epoxy resins, acrylate and methacrylate resins and their copolymers, polyurethane resins and polyamide resins are used together with microcapsules. You can also do it.

The support used in the present invention may be transparent or opaque. The transparent support preferably has high transparency and does not absorb at the wavelength of the irradiation laser beam. The thickness of the support is 10 μm to 200 μm.

As such a transparent support, for example,
Polyester film such as polyethylene terephthalate or polybutylene terephthalate, cellulose derivative film such as cellulose triacetate film, polystyrene film, polypropylene film, polyolefin film such as polyethylene film, polyimide film, polyvinyl chloride film, polyvinylidene chloride film,
Examples thereof include polyacrylic films and polycarbonate films, which can be used alone or in combination.

On the other hand, examples of the opaque support for the recording material include paper, synthetic paper, aluminum vapor deposition base, and the above-mentioned transparent support coated with a pigment. In this case,
In order to irradiate the laser beam from the heat-sensitive layer side so that the heat-sensitive layer can be efficiently absorbed, it is preferable to use an opaque support of the recording material having a high laser-beam reflectivity.

The support used in the present invention is preferably a polyester film which has been subjected to heat treatment and antistatic treatment. In the present invention, in order to prevent the entire heat-sensitive layer from peeling off from the support, it is desirable to provide an undercoat layer on the support before applying the heat-sensitive layer containing microcapsules and the like on the support.

As the undercoat layer, an acrylic acid ester copolymer, polyvinylidene chloride, SBR, aqueous polyester or the like can be used, and the film thickness is 0.1 to 0.
5 μm is desirable.

The undercoat layer composed of these compositions is coated by a known coating method such as a blade coating method, an air knife coating method, a gravure coating method, a roll coating coating method, a spray coating method, a dip coating method and a bar coating method. To be done.
The coating amount is preferably 1 to ²⁰ g / m ² , particularly 3 to 10 g
/ M ² is preferable.

If desired, pigments, waxes, hardeners, etc. may be added to the heat-sensitive layer. The heat-sensitive layer should be coated such that the electron-donating colorless dye, the electron-accepting compound having a polymerizable group, and the near-infrared absorbing polymerization initiator are 0.1 to 10 g, and the thickness of the layer is 1 to 10. It is desirable that the coating be performed so that the thickness is 10 μm. Further, a slipping agent such as wax may be applied in order to prevent the dye from being physically transferred by adhesion with the heat-sensitive layer. A protective layer may be provided for the same purpose.

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

When the recording material of the present invention is subjected to the above imagewise exposure, it is subjected to a heat development treatment after the imagewise exposure. As a heating method in this heat development treatment, various conventionally known methods can be used. The heating temperature is generally 80 ° C to 200 ° C.
° C, preferably 100 ° C to 160 ° C.
The heating time is 1 second to 5 minutes, preferably 3 seconds to 1 minute. Alternatively, the entire surface may be exposed after the heat development process to photo-cur the uncured portion.

The heat-sensitive layer of the recording material of the present invention is formed by applying a coating solution containing an electron-accepting compound having a polymerizable group and a near-infrared absorbing polymerization initiator as an emulsion. High transparency and less reflection of laser beam. Also, while light absorption in the visible light region is small,
Since the recording material contains an infrared absorbing dye that absorbs infrared rays particularly well, the background of the recording material is less colored and the absorption efficiency of infrared laser is high. Therefore, the laser beam in the portion of the heat-sensitive layer irradiated with the laser is efficiently absorbed, so that radicals are generated from the near-infrared absorbing polymerization initiator contained in the heat-sensitive layer and the electron-accepting property of having a polymerizable group. The compound is easily polymerized, and by the subsequent heat development, the electron-donating colorless dye encapsulated in the microcapsules undergoes a color reaction with the unpolymerized electron-accepting compound outside the microcapsules to form a good image.

[0078]

According to the recording material of the present invention, the heat-sensitive layer has high transparency and hardly reflects a laser beam. In addition, since the heat-sensitive layer contains an infrared-absorbing dye that absorbs infrared rays particularly well, the absorption efficiency of infrared laser is high and the polymerization sensitivity is high, even though the background of the recording material is not colored. Moreover, high-quality heat-sensitive recording can be performed.

[0079]

EXAMPLES The present invention will be described in more detail with reference to Examples below.
The present invention is not limited to this.

(Example 1) 1). [Preparation of Electron Donor Colorless Dye Capsule Liquid] 3,3-bis (1-octyl-2-methylindole)
8.9 g of 3-yl) phthalide was dissolved in 16.9 g of ethyl acetate, and 20 g of Takenate D-110N (manufactured by Takeda Pharmaceutical Co., Ltd.) and 2 g of Millionate MR200 (manufactured by Nippon Polyurethane Industry Co., Ltd.) were added. .. Add this solution to 8
% Phthalated gelatin (41 g) and 10% sodium dodecylbenzenesulfonate solution (1.4 g) were added to the mixture and emulsified and dispersed at 20 ° C. to obtain an emulsion. 14 g of water and 71 g of a 2.9% triethylenepentamine aqueous solution were added to the obtained emulsion, and the mixture was heated to 60 ° C. with stirring, and after 2 hours, a capsule liquid having an average particle size of 0.5 μm was obtained.

2). [Preparation of Emulsion of Photocurable Composition] As a near-infrared absorbing polymerization initiator, a solution of 0.12 g of a near-infrared absorbing dye (IR820B) represented by the following structural formula (I) in 3 g of isopropyl acetate was used. As a compound, 8 g of 3-chloro-4-hydroxybenzoic acid- (6-methacryloyloxyhexyl) ester was added. Add this solution to 1
The mixture was added to a mixed solution of 13 g of 3% gelatin aqueous solution and 0.8 g of 2% nonylphenoxybutanesulfonic acid bis-2-ethylhexyl ester sodium salt aqueous solution, and emulsified with a homogenizer (manufactured by Nippon Seiki Co., Ltd.) at 10,000 rpm for 5 minutes. An emulsion of the photocurable composition was obtained. Structural formula (I)

[0082]

[Chemical 38]

3). [Preparation of coating liquid for heat-sensitive layer] 4 g of the electron-donating colorless dye capsule, 12 g of emulsion of the photosensitive composition and 12 g of 15% gelatin aqueous solution were mixed to prepare a coating liquid for heat-sensitive layer.

4). [Preparation of coating liquid for protective layer] 4.5 g of 10% gelatin aqueous solution, 4.5 g of distilled water and 2%
N-octylsulfonyl-N-propylglycine potassium salt aqueous solution 0.5 g and 2% triethylene glycol mono-p-nonylphenyl ether monosodium sulfobutyl ether aqueous solution 0.3 g and 2% N, N-bis (Vinylsulfonylacetyl) ethylenediamine aqueous solution 0.5 g and Syloid 72 (FUJI-DEVISON CHEM
ICHAL LTD. The coating liquid for the protective layer was prepared by mixing the above products in an amount such that the coating amount was 50 mg / m ² .

5). [Preparation of test sample] A 100 μm thick polyethylene terephthalate film support was coated with a coating solution for the light and heat sensitive layer using a coating bar so that the dry weight of the coating layer was 8 g / m ^2. , Dried at 30 ° C for 10 minutes. A coating solution for protective layer was applied onto this layer using a coating bar so that the dry weight of the coating layer was 2 g / m ² , and the sample was similarly dried to obtain a sample.

From the heat-sensitive layer side of the heat-sensitive recording material prepared as described above, a semiconductor laser beam (G
aAs bonding laser) was imagewise irradiated. The output of this laser was adjusted so that the energy of the surface of the heat sensitive layer was 40 mJ / cm ² . Then, using a hot plate at 110 ° C, 5
After heating for 2 seconds, a clear magenta colored image was obtained. The image density is 2.28, and the density of the non-image part is 0.
It was 10. In addition, in order to check the preservation of the obtained image, 4
When left at 0 ° C and 90RH% for 24 hours,
The color density of the image area did not change, and the fog density of the non-image area was 0.13.

(Example 2) 3,3-used in Example 1
A heat-sensitive recording material was prepared in the same manner as in Example 1 except that crystal violet lactone was used instead of bis (1-octyl-2-methylindolyl-3-yl) phthalide, and an image was recorded to give a clear image. A blue image was obtained. The transmission density of the colored portion of the obtained image was measured using a Macbeth densitometer and found to be 2.23.

Example 3 Instead of the electron-accepting compound having a polymerizable group used in Example 1, 3-chloro-4-hydroxybenzoic acid- (6-methacryloyloxyhexyl) ester, 2-chloro-4 was used. A thermosensitive recording material was prepared in the same manner as in Example 1 except that-(6-methacryloyloxyhexylsulfonyl) phenol was used, and an image was recorded to obtain a clear magenta colored image. When the transmission density of the colored portion of the obtained image was measured by using a Macbeth densitometer, it was 2.15 and the density of the non-image portion was 0.10. When the storability of the obtained image was evaluated in the same manner as in Example 1, the color density of the image area did not change, and the fog density of the non-image area was 0.10.

Example 4 Instead of the near infrared absorbing dye (IR820B) used in Example 1, the following structural formula (I
A thermosensitive recording material was prepared in the same manner as in Example 1 except that the compound of I) was used, and an image was recorded to obtain a clear magenta colored image. When the transmission density of the colored portion of the obtained image was measured using a Macbeth densitometer, it was 2.12, and the density of the non-image portion was 0.10. When the storability of the obtained image was evaluated in the same manner as in Example 1, the color density of the image area did not change, and the fog density of the non-image area was 0.
It was 10. Structural formula (II)

[0090]

[Chemical Formula 39]

(Comparative Example 1) When a recording material was prepared and an image was recorded in the same manner as in Example 1 except that the infrared absorbing dye used in Example 1 was not used, no image could be recorded. It was

Claims (1)

[Claims] 1. A coating liquid containing, on a support, a microcapsule containing at least an electron-donating colorless dye, and a photocurable composition containing an electron-accepting compound having a polymerizable group and a photopolymerization initiator. A thermal recording material for infrared laser recording, characterized in that, in the recording material provided by coating and drying, the photopolymerization initiator is a near-infrared absorbing polymerization initiator having photosensitivity at 600 nm or more.