JPH10198036A - Image forming material and image forming method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a digital recording material capable of processing in a light room or dry processing and ensuring high image strength by incorporating a photothermic converting agent, a hot alkali generating material and a UV- curing resin deprived of its curability by alkali. SOLUTION: This image forming material contains a photothermic converting agent, a hot alkali generating material and a UV-curing resin deprived of its curability by alkali on the substrate. A layer contg. the photothermic converting agent and the hot alkali generating material or further contg. a resin binder is called an alkali generating layer. The photothermic converting agent and the hot alkali generating material may exist in the same layer or separate layers. In the case of separate layers, a layer contg. the photothermic converting agent is formed as a layer closer to the substrate.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital recording material which can be processed in a bright room or dry processing and has a high image intensity.

[0002]

2. Description of the Related Art For image formation by ultraviolet exposure,
For example, JP-A-59-113435 and JP-A-60-2631
No. 43, JP-A-5-66558 and the like,
It is known that an acid is generated by exposure to ultraviolet light and the acid is used to cure an epoxy resin or the like. However, when printing and recording a digital image, it is difficult for a recording apparatus to apply ultraviolet rays in an image form.

As for infrared exposure, US Pat.
No. 40,699, No. 5,466,557, No. 5,
No. 491,046 and the like, a method of applying an image-like heat pattern by a high-output infrared laser, generating an acid by heat, and curing an epoxy resin or the like with the acid to form an image. Are known. However, in this method, it is difficult to generate an acid sufficient for curing, the curing is insufficient, and the image strength is insufficient for use in a printing plate or the like.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a digital recording material which can be processed in a bright room or dry processing and has a high image intensity.

[0005]

The above object of the present invention is achieved by the following means.

[0006] An image forming material comprising a support containing a photothermal conversion agent, a thermo-alkali generating substance, and an ultraviolet curable resin whose curability is lost by alkali.

An image forming material having, on a transparent support, an ultraviolet curable substance layer whose curability is lost due to alkali, an ultraviolet absorbing layer, a layer containing a photothermal conversion substance and a thermal alkali generating substance (alkali generating layer) in this order, has an alkali. An image characterized by exposing high illuminance light having a wavelength in the visible or infrared region in an image form from the generation layer side, then exposing the entire surface with ultraviolet light from the transparent support side, and removing the portion exposed with the high illuminance light. Forming method.

[0008] An image-forming material comprising an ultraviolet-curable resin layer, which loses curability due to alkali on a support, a layer containing a photothermal conversion substance and a thermal alkali-generating substance (alkali-generating layer), and a cover sheet in this order, is a cover sheet. Irradiate high-intensity light in an image form from the side, remove the cover sheet and the layer containing the photothermal change substance, perform UV exposure on the entire surface of the UV-curable resin layer, and remove the UV-cured resin layer exposed in the high-intensity light. An image forming method characterized by removing.

Hereinafter, the present invention will be described in detail.

Hereinafter, in the present invention, an ultraviolet curable resin whose curability is lost by alkali is simply referred to as a UV resin.

As described above, it is difficult to imagewise expose ultraviolet rays. Therefore, the present inventor paid attention to the fact that the curing of UV resin by an acid is inhibited in an alkaline environment, After imagewise exposure to form an imagewise alkaline atmosphere from the alkali generating layer, it was found that the entire surface was exposed to ultraviolet light to cause crosslinking of the UV resin outside the alkaline atmosphere to form an image.

The crosslinked UV resin thus obtained had a sufficient image intensity because of being given sufficient exposure.

Hereinafter, in the present invention, a layer containing a light-to-heat conversion agent, hot alkali generation and, if necessary, a binder resin is referred to as an alkali generation layer. The photothermal conversion agent and the thermal alkali generator may be present in the same layer or in different layers. In the case of a separate layer, the layer containing the photothermal conversion agent is a layer close to the support.

(Image Forming Process) Preferred embodiments of the image forming material of the present invention include the following layer constitutions.

On a transparent support, a UV resin layer, an ultraviolet absorbing layer, and an alkali generating layer are provided in this order. After exposing the image forming material to high illuminance light in an image form from the alkali generating layer side, the entire surface is exposed to ultraviolet light from the transparent support side. Thereafter, a portion corresponding to the portion of the UV resin layer exposed to the high illuminance light is removed to form an image.

A UV resin layer, an alkali generation layer, and a cover sheet are provided on a support in this order. After exposing the image forming material to high illuminance light in an image form from the cover sheet side,
After peeling off between the alkali generating layer and the UV resin layer and removing the cover sheet and the alkali generating layer, the entire surface of the UV resin layer is exposed to ultraviolet light. Thereafter, a portion corresponding to the portion of the UV resin layer exposed to the high illuminance light is removed to form an image.

(Thermal Alkali Generator) Examples of the thermal alkali generator used in the present invention include salts of a carboxylic acid and an organic base. A base precursor consisting of a salt of a carboxylic acid and an organic base is disclosed in U.S. Pat.
374, British Patent No. 998,949, JP-A-59-949.
No. 1,805,371, JP-A-61-51139, U.S. Pat. No. 4,060,420 and the like can be used. The base precursor comprising a salt of a carboxylic acid and an organic base is configured to release an organic base at the time of use (at the time of heating) by utilizing the property that a carboxyl group of the carboxylic acid is decarboxylated by heating. I have.

(Light-to-heat conversion agent) Examples of light-to-heat conversion materials include carbon black, graphite, and JP-A-52-2084.
2, metal blacks such as gold, silver, aluminum, chromium, nickel, antimony, tellurium, bismuth, and selenium described in JP-A Nos. 63-139191 and 64-33.
No. 547, JP-A-1-160683 and 1-2807
Nos. 50, 1-293342, 2-2074, 3-26593, 3-30991, 3-348
Nos. 91, 3-36093, 3-36094, 3-36095, 3-42281, 3-975
Nos. 89 and 3-103476; organic compounds such as cyanine-based, polymethine-based, azurenium-based, squarium-based, thiopyrylium-based, naphthoquinone-based and anthraquinone-based dyes, phthalocyanine-based, azo-based, and the like.
A thioamide-based organometallic complex or the like is appropriately used.

(UV Resin) For forming a UV resin composition, it can be formed by a composition mainly composed of an ultraviolet curable prepolymer and / or a monomer and a polymerization initiator.

As the UV-curable prepolymer and monomer, there are a type in which a polymer is formed by radical polymerization (mainly an acrylate type) and a type in which a polymer is formed by cationic polymerization (mainly epoxy type).
For the purpose of this invention, epoxy type ultraviolet curable prepolymers and monomers are preferred.

Examples of the epoxy prepolymer and monomer include a prepolymer having two or more epoxy groups in one molecule. Examples of such prepolymers include alicyclic polyepoxides, polyglycidyl esters of polybasic acids, polyglycidyl ethers of polyhydric alcohols, polyglycidyl ethers of polyoxyalkylene glycol, and polyglycidyl of aromatic polyol. Examples include ethers, hydrogenated compounds of polyglycidyl ethers of aromatic polyols, urethane polyepoxy compounds, and epoxidized polybutadienes. One of these prepolymers can be used alone, or two or more of them can be used as a mixture. The content of the prepolymer having two or more epoxy groups in one molecule of the UV resin is preferably 70% by weight or more.

As the acrylate monomer or prepolymer, for example, 2-ethylhexyl acrylate, 2
Monofunctional acrylates such as -hydroxyethyl acrylate and 2-hydroxypropyl acrylate and derivatives thereof or compounds obtained by replacing these acrylates with methacrylate, itaconate, crotonate, maleate, etc., polyethylene glycol diacrylate, pentaerythritol diacrylate, bisphenol A
Diacrylates, bifunctional acrylates such as diacrylate of ε-caprolactone adduct of neopentyl glycol hydroxybivalate and derivatives thereof or acrylates of these methacrylates, itaconates,
Compounds substituted for crotonate, maleate, etc., or trimethylolpropane triacrylate, EO-modified isocyanuric acid triacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate, pyrogallol Examples include polyfunctional acrylates such as triacrylate and derivatives thereof, and compounds in which these acrylates are replaced with methacrylate, itaconate, crotonate, maleate, and the like.

Also, a so-called prepolymer obtained by introducing acrylic acid or methacrylic acid into an oligomer having an appropriate molecular weight and imparting photopolymerizability can be suitably used.

As the polymerization initiator, a cationic polymerization initiator is preferable, and specific examples thereof include aromatic onium salts and triazine compounds.

As this aromatic onium salt, V in the periodic table
Salts of Group a elements, such as phosphonium salts (such as triphenylphenacylphosphonium hexafluorophosphate), salts of Group VIa elements such as sulfonium salts (such as triphenylsulfonium tetrafluoroborate,
Triphenylsulfonium hexafluorophosphate, tris (4-thiomethoxyphenyl) hexafluorophosphate, triphenylsulfonium sulfonium and hexisafluoroantimonate, and salts of Group VIIa elements, such as iodonium salts (eg, diphenyliodonium chloride) Etc.).

The use of such an aromatic onium salt as a cationic polymerization initiator in the polymerization of an epoxy compound is disclosed in US Pat. Nos. 4,058,401 and 4,058,401.
Nos. 69,055, 4,101,513 and 4,161,478.

Preferred cationic polymerization initiators include
Examples include sulfonium salts of Group VIa elements. Among them, triarylsulfonium hexafluoroantimonate is preferred from the viewpoint of ultraviolet curability and storage stability of the ultraviolet curable composition.

As the UV resin used in the present invention, an alkali-soluble resin which causes a crosslinking reaction under acidic conditions can also be used. The alkali-soluble resin is not particularly limited, but for example, a resin having a phenolic hydroxyl group is preferable. As such a resin, phenol, cresol, ethylphenol, t-butylphenol, xylenol, a novolak resin obtained by condensation polymerization of a hydroxyaromatic compound such as naphthol with an aldehyde such as formaldehyde, acetaldehyde or benzaldehyde, and having a substituent such as a lower alkyl group. And an N- (p-hydroxyphenyl) maleimide polymer. Among them, cresol novolak resins and polyvinylphenol derivatives are preferred.

The crosslinking agent is not particularly limited as long as it is a compound which undergoes a crosslinking reaction with an alkali-soluble resin in the presence of an acid. For example, JP-A-59-113435 and JP-A-60-26 can be used.
Compounds cited in Nos. 3143 and 62-164045; Knop. L. A. Ph by Piraton
Compounds described in enolic Resins, in the molecule
Examples include compounds having an N (CH ₂ OR ¹ ) ₂ group or an —NH (CH ₂ OR ² ) group (where R ¹ and R ² each represent a hydrogen atom or an alkyl group).

As the acid generator used in the present invention, the compounds mentioned as the cationic polymerization initiator can be used.

[0031] In the coating agent for the UV resin layer,
Further, surfactants such as oils (especially silicone oils), silicone-alkylene oxide copolymers (eg, L-5410 commercially available from Union Carbide), aliphatic epoxides containing silicone oil, commercially available from 3M. FO-171 available from 3M Company, and Fluorocarbon surfactants such as Megafac F-141 available from Dainippon Ink Co., Ltd. may be contained.

In the UV resin layer coating agent,
Further, for example, styrene, paramethylstyrene, methacrylic acid esters, vinyl monomers such as acrylates, cellulose-based, thermoplastic polyester, phenyl glycidyl ether, silicon-containing monoepoxide, monoepoxides such as butyl glycidyl ether, and the like, It may be contained within a range that does not impair the effects of the present invention.

The UV resin layer coating agent contains, as an inactive component, a dye, a pigment, a thickener, a plasticizer,
Stabilizers, leveling agents, coupling agents, tackifiers,
Silicone group-containing activators, wetting improvers such as fluorocarbon group-containing surfactants, and other various additives, for the purpose of improving fluidity during application of the coating agent, hardly react with the cationic polymerization initiator. A small amount of a solvent such as acetone, methyl ethyl ketone, and methyl chloride may be contained.

(Support) As the support used in the present invention, for example, a metal plate such as aluminum, stainless steel, chromium, nickel, etc., for example, a plastic film such as polyester film, polyethylene film, polypropylene film, paper, synthetic paper, resin Examples include those obtained by laminating or vapor-depositing the above-mentioned metal thin film on coated paper, for example, those obtained by subjecting the surface of a polyester film, vinyl chloride film, nylon film or the like to a hydrophilic treatment.

(Hydrophilic treatment) When used as a printing plate, it is necessary to make the surface hydrophilic to make it hydrophilic. As the above-mentioned method for hydrophilizing a plastic film, sulfuric acid treatment, oxygen plasma etching treatment, corona discharge treatment, providing a water-soluble resin coating layer, and the like are preferably used.

An aluminum plate whose surface is grained, anodized and sealed is particularly preferable as a support for a printing plate. Examples of the graining method include a mechanical method and an electrolytic etching method.

Examples of the mechanical method include a ball polishing method, a brush polishing method, a polishing method using liquid honing, and a buff polishing method. The above-mentioned various methods can be used alone or in combination depending on the composition of the aluminum material and the like. Preferred is a method by electrolytic etching.

The electrolytic etching is performed in a bath containing one or more inorganic acids such as phosphoric acid, sulfuric acid, hydrochloric acid, and nitric acid. After the graining treatment, if necessary, a desmut treatment is performed with an aqueous solution of an alkali or an acid to neutralize and wash with water.

The anodic oxidation treatment is carried out by using a solution containing one or more of sulfuric acid, chromic acid, oxalic acid, phosphoric acid, malonic acid and the like as an electrolytic solution, and using an aluminum plate as an anode to perform electrolysis. The formed anodized coating amount is 1 to 50 m
g / dm ² is suitable, and preferably 10 to 40 mg / g.
dm ² . The anodic oxidation coating amount is determined, for example, by immersing an aluminum plate in a chromic phosphoric acid solution (prepared by dissolving 35 g of 85% phosphoric acid and 20 g of chromium oxide in 1 liter of water), dissolving the oxide film, and dissolving the coating of the plate. It can be determined from a change in weight before and after.

Examples of the sealing treatment include boiling water treatment, steam treatment, sodium silicate treatment, dichromate aqueous solution treatment, and the like. In addition, the aluminum plate support may be subjected to an undercoating treatment with an aqueous solution of a water-soluble polymer compound or a metal salt such as fluorinated zirconic acid. The hydrophilic support has a contact angle of water on its surface of 60 degrees or less,
More preferably, it is 40 degrees or less. The thickness of the hydrophilic support is 50 to 1000 μm, preferably 75 to 500 μm.
Range.

(Development treatment) As the developer, a conventionally known alkaline aqueous solution can be used. For example, sodium silicate, potassium, ammonium, dibasic sodium phosphate, potassium, ammonium, sodium bicarbonate, potassium, ammonium, sodium carbonate, potassium, ammonium, sodium hydrogen carbonate, potassium, potassium Inorganic alkaline agents such as ammonium, sodium borate, potassium, ammonium, sodium hydroxide, potassium, ammonium, and lithium. Also, monomethylamine, dimethylamine, trimethylamine, monoethylamine, diethylamine, triethylamine, monoisopropylamine, diisopropylamine, triisopropylamine,
Organic alkali agents such as n-butylamine, monoethanolamine, diethanolamine, triethanolamine, monoisopropanolamine, diisopropanolamine, ethyleneimine, ethylenediamine, and pyridine are also used. These alkaline agents can be used alone or
Used in combination of two or more.

If necessary, an organic solvent such as an anionic surfactant, an amphoteric surfactant or an alcohol can be added to the developer.

(Image Exposure Method) In the present invention, the light source for image exposure is a xenon lamp, a halogen lamp,
Examples thereof include a tungsten lamp, a laser, an LED, and a CRT, and any light source having a high light intensity can be used without being limited by the emission wavelength. A flash light source or a laser light source is preferably used as a light source.
As a flash light source, a xenon flash having an emission half width of 10 ms or less and an emission intensity of 10 W / cm ² or more is preferable. Suitable laser light sources include an argon laser, a helium neon laser, and a semiconductor laser having an output of 50 mW or more.

The exposure method using such a light source includes contact exposure and scanning exposure. In the case of contact exposure, the original transmission original and the recording material are brought into close contact with each other, and exposure is performed from the transmission original side with the high illuminance light. The exposure time in this case is preferably 10 ms or less. Exposure time is 10
If the time is longer than ms, the image quality deteriorates due to the diffusion of the thermal pattern.

In the case of the scanning exposure method, a cylindrical scanning optical system or a plane scanning optical system is used as a recording optical system. Among them, the cylindrical outer surface scanning optical system is most preferable because the loss of the light source is small and the beam can be narrowed down easily.

(Whole Surface Exposure Method) Examples of the light source used for the whole surface exposure with ultraviolet light include sunlight, a low-pressure mercury lamp, a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, a carbon arc lamp, a metal halide lamp, a xenon lamp, and the like. The atmosphere when irradiating the ultraviolet light may be air or an inert gas such as nitrogen gas or carbon dioxide gas. The time for irradiating the ultraviolet ray to the ultraviolet curable substance used in the present invention varies depending on the type of the irradiation light source in the above-mentioned ultraviolet region.
Minutes, preferably 3 seconds to 3 minutes.

At the time of curing, heating may be performed at the time of irradiation with ultraviolet light or before or after the irradiation to further shorten the irradiation time. When heating, the heating temperature is 30 ° C to 80 ° C
Is preferred. Before ultraviolet irradiation, the heating time may be short as long as the ultraviolet curable composition reaches this temperature, and after ultraviolet irradiation, the heating time is preferably 1 minute to 120 minutes.

(Ultraviolet Absorbent Layer) The ultraviolet absorbent layer is a layer having a function of reducing the transmittance of ultraviolet light used for the entire surface exposure. It can be obtained by coating a solution in which a dye or pigment absorbing ultraviolet light is dissolved or dispersed in a suitable binder.

It is desirable that the transmission density at the wavelength of the ultraviolet light used for the entire surface exposure is 1.0 to 5.0.
More preferably, it is 2.0 to 4.0. If the transmission density is low, the base may be diffused from the base generating layer at the time of overall exposure, and curing may be inhibited. When the transmission density is high, the ultraviolet shielding effect is sufficient, but the film thickness tends to be excessively large, and the penetration of the base during image exposure is suppressed.

[0050]

EXAMPLES The effects of the present invention will now be illustrated by examples.

Example 1 An image forming material having a UV resin layer having the following composition on an aluminum support subjected to graining and hydrophilic treatment was prepared.

Triarylsulfonium hexafluoroantimonate 3 parts by weight Diglycidyl hexahydrophthalate 20 parts by weight Hydrogenated bisphenol A glycidyl ether 30 parts by weight The following base generating layer is provided on a 30 μm thick polyester film to prepare an alkali generating sheet. did.

5 parts by weight of carbon black # 30 (manufactured by Mitsubishi Chemical Corporation) 5 parts by weight of base precursor P having the following structure

[0054]

Embedded image

The alkali-generating sheet layer side and the ultraviolet-curable resin layer of the above-mentioned image forming material were adhered and laminated.

After the recording material was image-exposed from the alkali generation sheet side with a 2 W semiconductor laser, the alkali generation sheet was peeled off, and the entire surface was exposed to ultraviolet light for 10 seconds.
After heating at 80 ° C. for 2 minutes, PS plate developer SDR-1
It was immersed in a 6-fold diluted solution (manufactured by Konica Corporation) for 30 seconds, washed with water and developed.

As a result, a positive type image was formed in which only the area exposed to the image by the semiconductor laser was removed.

Example 2 An image forming material having an image formation having a UV resin layer of the following composition having a thickness of 2 μm on an aluminum support subjected to graining and hydrophilization was prepared.

Resol resin 6 parts by weight Novolak resin 6 parts by weight Diphenyliodonium hexafluorophosphate 1 part by weight The following base generation layer is provided on a 30 μm thick polyester film at a dry film thickness of 0.5 μm to prepare an alkali generation sheet. did.

1 part by weight of infrared dye D 5 parts by weight of base precursor P

[0061]

Embedded image

The base generation layer side of this alkali generation sheet and the UV resin of the above-mentioned image forming material were adhered and laminated.

After the recording material was image-exposed from the alkali generating sheet side with a 2 W semiconductor laser, the alkali generating sheet was peeled off, and the entire surface was exposed to UV light for 10 seconds, and
After heating at 0 ° C. for 2 minutes, the plate was immersed in a 6-fold diluted solution of PS plate developer SDR-1 (manufactured by Konica Corporation) for 30 seconds, washed with water and developed.

As a result, a positive type image was formed in which only the area exposed to the image by the semiconductor laser was removed.

Comparative Example 1 An image forming material having a UV resin layer of the following composition having a thickness of 2 μm was formed on an aluminum support subjected to graining and hydrophilization.

Resol resin 6 parts by weight Novolak resin 6 parts by weight Diphenyliodonium hexafluorophosphate 1 part by weight Infrared dye D 1 part by weight After this recording material was image-exposed with a 2 W semiconductor laser from the alkali generation sheet side, PS Plate developer SDR-1
It was immersed in a 6-fold diluted solution (manufactured by Konica Corporation) for 30 seconds, washed with water and developed.

As a result, a negative type image was formed in which only the area exposed to the image by the semiconductor laser remained.

(Evaluation) A printing test was carried out on the printing plates prepared in Examples 1 and 2 and Comparative Example 1, and the printing test was carried out. All of them exhibited printing durability of 100,000 sheets or more, whereas the printing plate of the comparative example was inferior in printing durability, starting with the loss of small dots in the image area on about 50,000 sheets.

[0069]

According to the present invention, it is possible to provide a digital recording material which can be processed in a bright room or dry processing and has a high image intensity.

Claims (3)

[Claims] 1. An image-forming material comprising, on a support, a photothermal conversion agent, a thermal alkali-generating substance and an ultraviolet curable resin whose curability is lost by alkali. 2. An image forming material comprising, on a transparent support, an ultraviolet-curable resin layer whose curability is lost by alkali, an ultraviolet-absorbing layer, a layer containing a photothermal conversion substance and a thermal alkali-generating substance (alkali-generating layer) in this order. First, imagewise high-intensity light having a wavelength in the visible or infrared region is exposed imagewise from the light-heat conversion material-containing layer side, and then the entire surface is exposed to ultraviolet light from the transparent support side, and then the portion exposed to high-intensity light is removed. An image forming method comprising: 3. An image forming material having a UV curable substance layer whose curability is lost by alkali, a layer containing a photothermal conversion substance and a thermal alkali generating substance (alkali generating layer), and a cover sheet in this order on a support. Irradiate high-intensity light in an image form from the cover sheet side, remove the cover sheet and the light-to-heat conversion material-containing layer, perform full-surface exposure to ultraviolet light from the ultraviolet-curable resin layer side, and expose the portion exposed to high-intensity light. An image forming method comprising removing an ultraviolet curable resin layer.