JP2000238436A - Laser recording heat-sensitive proof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To manufacture a laser recording heat-sensitive proof of sufficient heat-sensitivity and resistance to scuffing for recording the image quality equivalent to a printing block. SOLUTION: In a heat-sensitive proof, characters or patterns are formed by laser beams and heat-sensitive layer or layers containing at least a dye for carrying out the photothermal conversion by absorbing characters or patterns by laser beams, an electron donative leuco dye and an electron acceptive developer for coloring the electron donative leuco dye are formed on one face or both faces of a substrate, and an overcoat layer or layers containing inorganic oxide fine particles are formed on the heat-sensitive layer or layers. The volume average particle diameters of inorganic oxide fine particles contained in the overcoat layer or layers is 2-100 nm, and inorganic oxide fine particles are selected from one or more of silica, alumina, zirconia and titania, and the ratio of inorganic oxide fine particles is 50-98 wt.% to the total solid weight of an overcoat layer constituting material.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser recording type heat-sensitive proof capable of obtaining a color image of a character or a pattern by irradiation with a laser beam. Here, the proof refers to a proof mainly required for calibration required in the printing process.

[0002]

2. Description of the Related Art A printing proof plays an important role for confirming a final printed image before a printing process. Many of the conventional printing methods that are not CTP (computer-to-plate) are processed through a process such as plate making and subsequent plate making. Proofs are often output using these materials. However, in the case of the CTP method, since digital data is directly output to the printing plate, a method of outputting the data by a different path from the printing plate is adopted.

When the size of the printing plate is smaller than A3, an ordinary computer output device such as an electrophotographic system can be used. However, when the plate size is larger than A2, the available output devices are limited. 2. Description of the Related Art In recent years, as a large-sized output device, a printer capable of large-format printing called an ink-jet plotter has been used as a proof output system of the CTP system.

There is also an output device called a thermal transfer type color proofer. When a laser is used as a heat source for drawing, an output equivalent to that of a printing plate is possible in terms of drawing quality such as resolution, and is used as a proof output device like an ink jet plotter.

[0005]

However, such a system has several problems. The ink-jet method has an inherent problem in that a sufficient resolution for confirming a printed image cannot be obtained. That is, when the resolution of the printing plate output is set to 2540 dpi, a resolution of 10 μm is required, but the size of one dot in the ink jet system is approximately 50 μm or more. This appears as a problem that a font of a character having a small series cannot be distinguished.

[0006] Further, in a thermal transfer type color proofer, a donor film is required, which causes a problem of disposal and an increase in the size of the apparatus and complicates maintenance. Further, as these problems, it is virtually impossible to make the printing plate the same method for converting image data and the like into a state ready for output. Not guaranteed.

[0007] Even in the case of the CTP method, in a printing plate image setter, instead of the printing plate, the image is output once to an underlay film or the like, and the film image is closely adhered to a diazo photosensitive paper or the like to obtain a proof. There is a way. According to this method, the identity between the printing plate and the output image of the proof is guaranteed. However, in this method, the output is complicated, and the image is deteriorated at the stage of the splicing of the film onto the paper.

[0008]

SUMMARY OF THE INVENTION The present invention relates to a proof in which a character or a pattern is formed by a laser beam, wherein the dye and the electron-donating leuco dye absorb at least the laser beam and perform photothermal conversion. A laser recording type comprising: providing a heat-sensitive layer containing an electron-accepting color developer for developing a leuco dye on one or both surfaces of a support; and providing an overcoat layer containing inorganic oxide fine particles on the heat-sensitive layer. It is a heat-sensitive proof, and the volume average particle diameter of the inorganic oxide fine particles contained in the overcoat layer is 2 to 10
It is preferably 0 nm, and the inorganic oxide fine particles contained in the overcoat layer are preferably one or more selected from silica, alumina, zirconia, and titania, and the ratio of the inorganic oxide fine particles contained in the overcoat layer. Is more preferably 50 to 98% by weight based on the total solid weight of the overcoat layer composition.

According to the present invention, a proof having the same quality as an image on a printing plate can be obtained without post-processing and without generating waste. When the image setter is of a thermal type, a special proof output device is not required, and proof output can be directly performed on the thermal proof of the present invention in the image setter. Further, by providing the overcoat layer according to the present invention, it is possible to obtain a laser recording type heat-sensitive proof having high scratch resistance and water resistance, which are important in terms of image protection of the proof for calibration, and high sensitivity.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of a laser recording type thermal proof will be described in detail. The heat-sensitive layer in the present invention contains a dye that absorbs laser light and performs photothermal conversion. As a dye that absorbs laser light and performs photothermal conversion, a dye that absorbs less light in the visible light region and particularly absorbs light having a wavelength in the infrared region equal to the oscillation wavelength region of the laser is preferable. Specifically, cyanine dyes, phthalocyanine dyes, pyrylium or thiopyrylium dyes, azulenium dyes, squalilium dyes, Ni, metal complex salt dyes such as Cr, naphthoquinone or anthraquinone dyes, indophenol dyes,
Examples include indoaniline dyes, triphenylmethane dyes, triallylmethane dyes, aminium or diimmonium dyes, and nitroso compounds.

Specific examples of the electron-donating leuco dye include triarylmethane compounds:
3-bis (p-dimethylaminophenyl) -6-dimethylaminophthalide (crystal violet lactone), 3,3-bis (p-dimethylaminophenyl) phthalide, 3- (p-dimethylaminophenyl) -3-
(1,2-dimethylindol-3-yl) phthalide,
3- (p-dimethylaminophenyl) -3- (2-methylindol-3-yl) phthalide, 3- (p-dimethylaminophenyl) -3- (2-phenylindole-
3-yl) phthalide, 3,3-bis (1,2-dimethylindol-3-yl) -5-dimethylaminophthalide, 3,3-bis (1,2-dimethylindole-3-
Yl) -6-dimethylaminophthalide, 3,3-bis (9-ethylcarbazol-3-yl) -5-dimethylaminophthalide, 3,3-bis (2-phenylindol-3-yl) -5 -Dimethylaminophthalide, 3-p
-Dimethylaminophenyl-3- (1-methylpyrrol-2-yl) -6-dimethylaminophthalide, 3- (1
-Ethyl-2-methylindol-3-yl) -3-
(4-dimethylamino-2-ethoxyphenyl) -4-
Azaphthalide, 3- (1-ethyl-2-methylindol-3-yl) -3- (4-dimethylamino-2-methylphenyl) -4-azaphthalide and the like.

The diphenylmethane compounds include:
4'-bis-dimethylaminophenylbenzhydryl benzyl ether, N-2,4,5-trichlorophenylleuco auramine and the like.

The xanthene compounds include: rhodamine B anilinolactam, rhodamine Bp-chloroanilinolactam, 3-diethylamino-7-dibenzylaminofluoran, 3-diethylamino-7-octylaminofluoran, Diethylamino-7-phenylfluoran, 3-diethylamino-7-chlorofluoran,
3-diethylamino-6-chloro-7-methylfluoran, 3-diethylamino-7- (3,4-dichloroanilino) fluoran, 3-diethylamino-7- (2-chloroanilino) fluoran, 3-diethylamino-6
Methyl-7-anilinofluoran, 3- (N-ethyl-
N-tolyl) amino-6-methyl-7-anilinofluoran, 3-piperidino-6-methyl-7-anilinofluoran, 3- (N-ethyl-N-tolyl) amino-6
Methyl-7-phenethylfluoran, 3-diethylamino-7- (4-nitroanilinofluoran, 3-dibutylamino-6-methyl-7-anilinofluoran, 3-
(N-methyl-N-propyl) amino-6-methyl-7
-Anilinofluoran, 3- (N-ethyl-N-isoamyl) amino-6-methyl-7-anilinofluoran,
3- (N-methyl-N-cyclohexyl) amino-6
Methyl-7-anilinofluoran, 3- (N-ethyl-
N-tetrahydrofuryl) amino-6-methyl-7-anilinofluoran and the like.

Examples of the thiazine compound include: benzoyl leucomethylene blue, p-nitrobenzoyl leucomethylene blue and the like.

The spiro compounds include: 3-methylspirodinaphthopyran, 3-ethylspirodinaphthopyran,
3,3'-dichlorospirodinaphthopyran, 3-benzylspirodinaphthopyran, 3-methylnaphtho- (3-methoxybenzo) spiropyran, 3-propylspirobenzopyran and the like can be mentioned alone or in combination of two or more. These can be mixed and used.

The electron-accepting developer generally includes phenol derivatives, aromatic carboxylic acid derivatives or metal compounds thereof, N, N'-diarylthiourea derivatives, salicylic acid derivatives and the like.

Specific examples include: p-phenylphenol, p-hydroxyacetophenone, 4-hydroxy-4'-methyldiphenylsulfone, 4-hydroxy-4'-isopropoxydiphenylsulfone, 4-hydroxy-4 ' -Benzenesulfonyloxydiphenyl sulfone, 1,1-bis (p-hydroxyphenyl) propane, 1,1-bis (p-hydroxyphenyl) pentane, 1,1-bis (p-hydroxyphenyl) hexane, 1,1- Bis (p-hydroxyphenyl) cyclohexane, 2,2-bis (p-hydroxyphenyl) propane, 2,2-bis (p-hydroxyphenyl) butane, 2,2-bis (p-hydroxyphenyl) hexane, 1-bis (p-hydroxyphenyl) -2-ethylhexane, 2,2- Scan (3-chloro-4-hydroxyphenyl) propane, 1,1-bis (p- hydroxyphenyl) -1-phenylethane, 1,3-di [2-
(P-hydroxyphenyl) -2-propyl] benzene, 1,3-di [2- (3,4-dihydroxyphenyl) -2-propyl] benzene, 1,4-di [2- (p
-Hydroxyphenyl) -2-propyl] benzene,
4,4'-dihydroxydiphenyl ether, 4,4 '
-Dihydroxydiphenylsulfone, 3,3'-dichloro-4,4'-dihydroxydiphenylsulfone, 3,
3'-diallyl-4,4'-dihydroxydiphenylsulfone, 3,3'-dichloro-4,4'-dihydroxydiphenylsulfide, methyl 2,2-bis (4-hydroxyphenyl) acetate, 2,2-bis ( 4-hydroxyphenyl) butyl acetate, 4,4'-thiobis (2-t
-Butyl-5-methylphenol), bis (3-allyl-4-hydroxyphenyl) sulfone, 4-hydroxy-4'-isopropyloxydiphenylsulfone,
3,4-dihydroxy-4'-methyldiphenylsulfone, benzyl p-hydroxybenzoate, chlorobenzyl p-hydroxybenzoate, propyl p-hydroxybenzoate, butyl p-hydroxybenzoate, dimethyl 4-hydroxyphthalate, gallic Benzyl, stearyl gallate, salicylanilide, 5-chlorosalicylanilide, 4-pentadecylsalicylic acid, 5-octadecylsalicylic acid, 3,5-di (t-butyl) salicylic acid, 3,
5-bis (1-phenylethyl) salicylic acid, 3- (1
-Phenylethyl) -5-t-butylsalicylic acid, and zinc salts and aluminum salts thereof, such as salicylanilide, 5-chlorosalicylanilide, 3,5-bis (1-
Phenylethyl) salicylanilide and the like.

Various pigments and additives for improving sensitivity can be used in the heat-sensitive layer. Specific examples of pigments include, as pigments, diatomaceous earth, talc, kaolin, calcined kaolin, calcium carbonate, magnesium carbonate, synthetic silica, colloidal silica, alumina, zinc oxide, silicon oxide, aluminum hydroxide, plastic pigment, binder pigment, Urea-formalin resin and the like, as additives, waxes such as N-hydroxymethyl stearamide, stearamide, palmitic amide, naphthol derivatives such as 2-benzyloxynaphthalene, p-benzylbiphenyl, Biphenyl derivatives such as 4-allyloxybiphenyl, 1,2-bis (3-methylphenoxy) ethane, and 2,2'-bis (4
-Methoxyphenoxy) diethyl ether, bis (4-
Polyether compounds such as methoxyphenyl) ether,
Diphenyl carbonate, dibenzyl oxalate, dioxalate (p
Carbonic acid or oxalic acid diester derivatives such as (fluorobenzyl) ester can be added.

As the binder used for the heat-sensitive layer, various binders which are usually used can be arbitrarily used. For example, starches, hydroxyethylcellulose, methylcellulose, carboxymethylcellulose,
Gelatin, casein, polyvinyl alcohol, modified polyvinyl alcohol, sodium polyacrylate, acrylamide / acrylate copolymer, acrylamide / acrylate / methacrylic acid terpolymer,
Water-soluble adhesives such as alkali salts of styrene / maleic anhydride copolymer, alkali salts of ethylene / maleic anhydride copolymer, polyvinyl acetate, polyurethane, polyacrylate, styrene / butadiene copolymer, acrylonitrile / Butadiene copolymer, methyl acrylate /
Latexes such as butadiene copolymer and ethylene / vinyl acetate copolymer are exemplified.

The heat-sensitive layer is formed by mixing a dye that absorbs laser light to perform photothermal conversion, an electron-donating leuco dye, and an electron-accepting developer that develops an electron-donating leuco dye to form a heat-sensitive layer. Of the three components, a heat-sensitive layer can be formed as a two-layer structure by forming a coating layer in the lower layer with only the dye, and further forming a coating layer in the upper layer with the leuco dye and the developer. The heat-sensitive layer can be provided on any one or both sides of the support. When provided on only one side, the layer on the opposite side may contain a material on which information can be recorded electrically, optically, and magnetically, for the purpose of preventing blocking, preventing curling, preventing charging, improving running properties, and the like. As a back coat layer.

The overcoat layer in the present invention is important for the purpose of protecting the image of the heat-sensitive layer. In other words, the proof for proof plays the role of the final verification of the output to the printing plate, and unexpected coloring or missing of the image lowers the accuracy of the verification. For this reason, by providing an overcoat layer, it is necessary to protect the image and ensure the accuracy of the test. Such an overcoat layer is provided on the heat-sensitive layer. The overcoat layer contains inorganic oxide fine particles. In the present invention, the inorganic oxide fine particles, in addition to oxides, hydroxides, hydrated oxides,
And composites thereof. These inorganic oxide fine particles may be subjected to a surface modification treatment on the surface of the dispersed particles with an appropriate surface coating agent in order to improve ionicity and dispersion stability. Further, in the present invention, a fine particle dispersion of these inorganic oxides is used, and as a dispersion stabilizer, a cation derived from an alkali metal and ammonium or the like, or an anion derived from acetic acid, hydrochloric acid, nitric acid, sulfuric acid or the like is used. May be included.

The preferred volume average particle diameter (hereinafter, abbreviated as average particle diameter) of the inorganic oxide fine particles according to the present invention is 2 to 1.
The range is 00 nm. When the average particle size is larger than 100 nm, the light blocking ratio increases, and as a result, due to the blocking of visible light, the contrast of a color-developed image decreases,
Due to the shielding of the laser beam, the sensitivity is reduced. If the average particle size of the fine particles is smaller than 2 nm, the specific surface area increases, and the dispersion stability of the particles is impaired. As a result, secondary particle clusters are formed, and the apparent average particle size significantly increases.

The inorganic oxide fine particles according to the present invention are preferably selected from one or more of silica, alumina, zirconia and titania. Such inorganic oxide fine particles are excellent in dispersion stability, have no characteristic absorption with respect to laser light or visible light, and do not cause unexpected color development, that is, fog when contacted with the heat-sensitive layer. .

The inorganic oxide fine particles according to the present invention preferably have a ratio (hereinafter abbreviated as an addition ratio) to the total solid content of the components of the overcoat layer, which is 50 to 98 wt%. In the composition of the overcoat layer, as components other than the inorganic oxide fine particles, a binder, a dispersant,
Examples include a pH adjuster, a surfactant, and a crosslinking agent. When the addition ratio of the inorganic oxide fine particles is lower than 50 wt%, an organic substance having a binder as a main component other than the inorganic oxide fine particles penetrates the heat-sensitive layer provided below, and the leuco dye and the developer And hinders movement due to melting during laser exposure, resulting in a decrease in heat sensitivity. On the other hand, if the addition ratio of the inorganic oxide fine particles is higher than 98 wt%, the ratio of the binder other than the inorganic oxide fine particles will be insufficient, and the coating strength of the overcoat layer will decrease. Note that the overcoat layer may be composed of two or three or more layers. As the binder that can be used for the overcoat layer, the same substance as the binder for the heat-sensitive layer can be used. In addition, a dispersant, a pH adjuster, a surfactant, a crosslinking agent, and the like can be optionally used.

The support used in the present invention is paper,
Various nonwoven fabrics, woven fabrics, plastic films such as polyethylene terephthalate and polypropylene, polyethylene,
Film-laminated paper, synthetic paper laminated with synthetic resin such as polypropylene and polyethylene terephthalate,
A metal foil such as aluminum, glass or the like, or a composite sheet combining these can be used arbitrarily according to the purpose, but is not limited thereto. In the present invention, synthetic paper made of the same material as the plastic film is also included in the range of the plastic film. These may be opaque, transparent, or translucent. In order to make the background appear white or another specific color, a white pigment, a colored dye, a bubble, a resin, or the like may be contained in the support or on the surface of the support. When the hydrophilicity of the support surface is small and it is difficult to apply the aqueous coating liquid, easy adhesion such as hydrophilic treatment of the support surface by corona discharge, rough surface treatment, or application of various polymers to the support surface is performed. Processing may be performed. In addition, a treatment necessary for straightening curl, preventing static charge, or improving running properties may be performed.

In many cases, it is convenient to mix and apply the components contained in the above-mentioned heat-sensitive layer as an aqueous dispersion, an aqueous emulsion or an aqueous solution. For the application of a layer containing a resin or the like, an organic solvent may be used as a medium instead of water. In that case, the resin in the coating liquid may be in a dispersed state or a solution state.

As a coating method, for example, an air knife method,
Curtain coating method, roller coating method, doctor coating method, wire bar coating method, slide coating method, gravure coating method, hopper-based extrusion coating method, microgravure coating method, lip coating method, die coating method, blade coating method, etc. You can do it.

The thickness of the heat-sensitive layer in the present invention is from 0.5 to
It is preferably in the range of 6 μm. Such a thickness,
When the thickness is less than 0.5 μm, the heat capacity per unit area of the heat-sensitive layer is not sufficient, and a sufficient amount of heat generation for forming color of the heat-sensitive layer cannot be obtained. On the other hand, if the thickness is more than 6 μm, the diffusion ratio of heat in the heat-sensitive layer increases, and the temperature does not reach a sufficient temperature for forming a color.

The thickness of the overcoat layer in the present invention is preferably in the range of 0.3 to 3 μm. When the thickness of the overcoat layer is smaller than 0.3 μm, the coating of the heat-sensitive layer tends to be incomplete, and it is difficult to exhibit the original function as the overcoat layer. When the thickness is more than 3 μm, the influence of the laser light shielding by the overcoat layer increases,
In addition, the heat capacity becomes large, and the temperature of the heat-sensitive layer does not reach a sufficient temperature for forming color.

As a specific example of the laser used for recording the heat-sensitive recording material in the present invention, the oscillation wavelength is 760 to 760.
Examples thereof include a 1100 nm semiconductor laser and a solid-state laser such as YAG and YLF.

[0031]

EXAMPLES Hereinafter, the effects of the present invention will be described in more detail using examples, but the present invention is not limited thereto. In the examples, "parts" and "%" indicate "parts by weight" and "% by weight", respectively.

<Preparation of Thermal Coating Solution 1> A 0.5% methanol solution of the dye compound represented by Chemical Formula 1 is prepared, and an equal amount of a 10% methanol solution of a commercially available nylon resin [manufactured by Toray Industries, Inc.] is mixed. And a dye coating solution.

[0033]

Embedded image

<Preparation of Thermal Sensitive Coating Solution 2> ODB-2 [commercially available leuco dye, manufactured by Yamada Chemical Co., Ltd.] was dispersed / crushed in water using a paint conditioner to obtain a 30% dispersion. did. In addition, BPA (developing agent, bisphenol A) was similarly dispersed / crushed to obtain a 30% dispersion. A 10% aqueous solution of PVA117 [completely saponified polyvinyl alcohol, manufactured by Kuraray] was prepared as a binder. These three types were mixed in equal amounts to obtain a heat-sensitive coating solution.

<Preparation of Overcoat Coating Liquid 1> 100 parts of colloidal silica (volume average particle diameter 50 nm, 40% aquasol) was mixed with PVA117 as a binder.
[Completely saponified polyvinyl alcohol, made by Kuraray] 10
% Aqueous solution was added to prepare Overcoat Coating Solution 1. The addition ratio of the inorganic oxide fine particles in this coating solution is 80%.

<Preparation of Overcoat Coating Solution 2> Alumina sol (boehmite, volume average particle diameter 25 nm, 15%
(Aquasol) 100 parts, PV as binder
An overcoat coating solution 2 was prepared by adding 37.6 parts of a 10% aqueous solution of A117 [completely saponified polyvinyl alcohol, manufactured by Kuraray]. The addition ratio of the inorganic oxide fine particles in this coating solution is 80%.

<Preparation of Overcoat Coating Solution 3> PVA117 as a binder was added to 100 parts of zirconia sol (20% aquasol having a volume average particle diameter of 20 nm).
[Completely saponified polyvinyl alcohol, made by Kuraray] 10
% Aqueous solution was added to prepare Overcoat Coating Liquid 3. The addition ratio of the inorganic oxide fine particles in this coating solution is
80%.

<Preparation of Overcoat Coating Solution 4> Titania sol (volume average particle diameter 15 nm, 15% aqua sol)
To 100 parts, 37.6 parts of a 10% aqueous solution of PVA117 (completely saponified polyvinyl alcohol, manufactured by Kuraray) was added as a binder to prepare Overcoat Coating Liquid 4. The addition ratio of the inorganic oxide fine particles in this coating solution is
80%.

<Preparation of Overcoat Coating Solution 5> PVA117 as a binder was added to 100 parts of zirconia sol (20% aquasol having a volume average particle diameter of 20 nm).
[Completely saponified polyvinyl alcohol, made by Kuraray] 10
3.5% of an aqueous solution was added to prepare Overcoat Coating Solution 5. The addition ratio of the inorganic oxide fine particles in this coating solution is 98.3%.

<Preparation of Overcoat Coating Solution 6> PVA117 as a binder was added to 100 parts of zirconia sol (20% aquasol having a volume average particle diameter of 20 nm).
[Completely saponified polyvinyl alcohol, made by Kuraray] 10
% Aqueous solution was added to prepare Overcoat Coating Solution 6. The addition ratio of the inorganic oxide fine particles in this coating solution is 9
7.6%.

<Preparation of Overcoat Coating Solution 7> PVA117 as a binder was added to 100 parts of zirconia sol (20% aquasol having a volume average particle diameter of 20 nm).
[Completely saponified polyvinyl alcohol, made by Kuraray] 10
% Aqueous solution was added to prepare Overcoat Coating Solution 7. The addition ratio of the inorganic oxide fine particles in this coating solution was 53.3%.

<Preparation of Overcoat Coating Liquid 8> PVA117 as a binder was added to 100 parts of zirconia sol (20% aquasol having a volume average particle diameter of 20 nm).
[Completely saponified polyvinyl alcohol, made by Kuraray] 10
% Aqueous solution was added to prepare Overcoat Coating Liquid 8. The addition ratio of the inorganic oxide fine particles in this coating solution is 46.5%.

<Preparation of Overcoat Coating Solution 9> 100 parts of colloidal silica (volume average particle diameter 90 nm, 40% aquasol) was mixed with PVA117 as a binder.
[Completely saponified polyvinyl alcohol, made by Kuraray] 10
% Aqueous solution was added to prepare Overcoat Coating Liquid 9. The addition ratio of the inorganic oxide fine particles in this coating solution is 80%.

<Preparation of Overcoat Coating Solution 10> PVA 1 as a binder was added to 100 parts of colloidal silica (volume average particle diameter 109 nm, 40% aquasol).
100 parts of a 10% aqueous solution of 17 [completely saponified polyvinyl alcohol, manufactured by Kuraray Co., Ltd.] was added to prepare an overcoat coating liquid 10. The addition ratio of the inorganic oxide fine particles in this coating solution is 80%.

<Preparation of Overcoat Coating Liquid 11> PVA1 was used as a binder with respect to 100 parts of colloidal silica (volume average particle diameter 2.6 nm, 20% aquasol).
17 [Completely saponified polyvinyl alcohol, manufactured by Kuraray] and 50 parts of a 10% aqueous solution were added thereto.
1 was produced. The addition ratio of the inorganic oxide fine particles in this coating solution is 80%.

<Preparation of Overcoat Coating Solution 12> Precipitating calcium carbonate (volume average particle diameter 500 nm, 20%
Slurry) PVA as binder for 100 parts
117 [Completely saponified polyvinyl alcohol, manufactured by Kuraray]
Then, 50 parts of a 10% aqueous solution was added to prepare an overcoat coating solution 12. The addition ratio of the inorganic particles in this coating solution is
80%.

<Preparation of heat-sensitive proof 1> Base paper basis weight 130
g / m ² , a resin coat obtained by laminating polyethylene on both sides is subjected to a corona discharge treatment, and the heat-sensitive coating solution 1 is applied so that the thickness of the coating layer after drying becomes 2 μm. Coating is performed so that the thickness of the applied amount after drying is 3 μm, and after drying, the overcoat coating solution 1 is applied and dried so that the thickness of the applied amount after drying is 1.3 μm to obtain a heat-sensitive proof 1. Was.

Example 2 <Preparation of heat-sensitive proof 2> Except for using the overcoat coating solution 2, a method similar to that of the heat-sensitive proof of Example 1 was used.
Thermal proof 2 was obtained.

Example 3 <Preparation of heat-sensitive proof 3> The same method as in the heat-sensitive proof of Example 1 was used except that the overcoat coating solution 3 was used.
Thermal proof 3 was obtained.

Example 4 <Preparation of heat-sensitive proof 4> A method similar to the heat-sensitive proof of Example 1 was used, except that the overcoat coating solution 4 was used.
Thermal proof 4 was obtained.

Example 5 <Preparation of heat-sensitive proof 5> A heat-proof proof 5 was prepared in the same manner as in Example 1 except that the overcoat coating solution 5 was used.
A heat-sensitive proof 5 was obtained.

Example 6 <Preparation of heat-sensitive proof 6> A heat-proof proof 6 was prepared in the same manner as in Example 1 except that the overcoat coating solution 6 was used.
A heat-sensitive proof 6 was obtained.

Example 7 <Preparation of heat-sensitive proof 7> A heat-proof proof 7 was prepared in the same manner as in Example 1 except that the overcoat coating solution 7 was used.
Heat proof 7 was obtained.

Example 8 <Preparation of heat-sensitive proof 8> A method similar to the heat-sensitive proof of Example 1 was used except that the overcoat coating solution 8 was used.
A heat-sensitive proof 8 was obtained.

Example 9 <Preparation of heat-sensitive proof 9> A heat-proof proof 9 was prepared in the same manner as in Example 1 except that the overcoat coating solution 9 was used.
A heat-sensitive proof 9 was obtained.

Example 10 <Preparation of Thermal Sensitive Proof 10> Overcoat Coating Solution 10
Was used in the same manner as in the heat-sensitive proof of Example 1 except that the heat-sensitive proof 10 was used.

Example 11 <Preparation of heat-sensitive proof 11> Overcoat coating solution 11
Was used in the same manner as in the heat-sensitive proof of Example 1 except that the heat-sensitive proof 11 of Example 1 was used.

Comparative Example 1 <Preparation of Thermal Sensitive Proof 12> PVA 117 [completely saponified polyvinyl alcohol,
Thermal proof 12 was obtained in the same manner as in the thermal proof of Example 1 except that a 10% aqueous solution of Kuraray Co., Ltd. was used.

Comparative Example 2 <Preparation of heat-sensitive proof 13> A heat-sensitive proof 13 was obtained in the same manner as in Example 1 except that the overcoat layer was not provided.

Comparative Example 3 <Preparation of Thermal Sensitive Proof 14> Overcoat Coating Solution 12
A heat-sensitive proof 14 was obtained in the same manner as in the heat-proof proof of Example 1 except that the heat-resistant proof was used.

<Evaluation method> 1) Recording by laser Recording was performed under the following conditions. Laser: 830 nm, 500 mW semiconductor laser (CW mode) Beam diameter: 12 μm φ on plate surface Modulation: Voltage modulator with maximum frequency of 1 MHz Scanning: Outer drum Circumference: 508 mm, 5, 10 rps
Image data: Chart including solid and fine lines at 2400 dpi. The applied energy is 1300 mJ / c at 5 rps.
It is equivalent to 650 mJ / cm ² at m ² and 10 rps.

2) Measurement of Density The reflection optical density of the solid portion was measured. The reflection optical density was measured using a Macbeth reflection densitometer (RD-918).

3) Evaluation of Scratch Resistance A 20 mm square nickel plate was placed on an unexposed sample for 40 minutes.
The sample was pressed with a load of 0 g and moved horizontally with the nickel plate at a speed of 10 cm / sec. The surface was visually observed for the state of disintegration / peeling and the state of color development. did.

<Results of Evaluation>

[0065]

[Table 1]

<Evaluation Results> In the examples, 10 r
In the case of ps, the coloring density when applying energy of 650 mJ / cm ² is sufficient, but in Example 10 in which the volume average particle diameter of the inorganic oxide fine particles is larger than 100 nm, the reflection density is lower, that is, the heat sensitivity Is low. Also, in Example 8 in which the addition ratio of the inorganic oxide fine particles is lower than 50%, the reflection density is low, that is, the heat sensitivity is low. In addition, when the inorganic oxide fine particles in Comparative Example 1 were not added to the overcoat layer, the print density was low, which hindered practical use. Although the abrasion resistance is good in the examples, the film strength of the overcoat layer is weak and the abrasion resistance is slightly poor in the example 5 in which the addition ratio of the inorganic oxide fine particles is higher than 98%. . Further, in both the examples and the comparative examples, the printing quality was the same as the image output on the printing plate. From the above results, according to the present invention, it is possible to obtain a heat-sensitive proof having a high reflection sensitivity, a high heat sensitivity, excellent scratch resistance, and an image quality comparable to that of a printing plate, with a low reflection density.

[0067]

According to the thermal proof of the present invention, the thermal proof has sufficient thermal sensitivity, has high abrasion resistance and water resistance which are important in terms of image protection of the proof for calibration, and has image quality equivalent to that of a printing plate. A proof image can be recorded.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) B41M 5/18 101C

Claims (4)

[Claims] 1. A proof in which a character or a pattern is formed by a laser beam, wherein the laser beam absorbs at least a laser beam to perform photothermal conversion, an electron-donating leuco dye, and an electron-accepting leuco dye. A laser recording type heat-sensitive proof, wherein a heat-sensitive layer containing a color developer is provided on one or both surfaces of a support, and an overcoat layer containing inorganic oxide fine particles is provided on the heat-sensitive layer. 2. The laser recording thermosensitive proof according to claim 1, wherein the volume average particle diameter of the inorganic oxide fine particles contained in the overcoat layer is 2 to 100 nm. 3. The method according to claim 1, wherein the inorganic oxide fine particles contained in the overcoat layer are at least one selected from the group consisting of silica, alumina, zirconia and titania.
Or a laser recording type thermosensitive proof according to 2. 4. The laser recording according to claim 3, wherein the ratio of the inorganic oxide fine particles contained in the overcoat layer is 50 to 98 wt% based on the total solid weight of the overcoat layer constituent. Type thermal proof.