JPH0285856A - Photosensitive resin plate material for letterpress printing plate and intaglio printing plate - Google Patents

Abstract

PURPOSE:To efficiently perform a photomechanical process by incorporating a pigment precursor forming a pigment when irradiated with active rays of light and a thiol compd. CONSTITUTION:A resin layer contg. a pigment precursor forming a pigment in only the photoset part irradiated with active rays of light by 0.001-5wt.%, preferably 0.05-1wt.% of the amt. of photosensitive resin and a thiol compd. such as n-octylthiol or n-nonylthiol by 0.05-5wt.% of the amt. of the photosensitive resin is formed on a base such as a metal sheet or a plastic film to obtain a photosensitive resin plate material for a letterpress printing plate or an intaglio printing plate. The leuco body of a spiropyrane compd. or a triarylmethane pigment which develops a color clearly is preferably used as the pigment precursor. A printed picture can be clearly and visually observed and a photomechanical process can be efficiency performed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a photosensitive resin letterpress material and an intaglio material.

BACKGROUND ART Photosensitive resin letterpress or intaglio materials, which are formed by providing a photocurable photosensitive resin layer on a base material such as a metal or plastic film, are widely used.

Among these, letterpress materials are made by directly or indirectly bringing an original film with a negative pattern into close contact with a photosensitive resin layer, and then irradiating actinic light to harden the photosensitive resin layer corresponding to the transparent part of the original film. . Next, by dissolving the uncured photosensitive resin layer corresponding to the opaque areas of the original film with a suitable solvent such as alcohol, alcohol/water, or water, a relief pattern faithful to the original film is formed on the substrate. It is something.

On the other hand, intaglio materials are produced by directly or indirectly bringing an original film having a positive pattern into close contact with a photosensitive layer, and then irradiating the film with actinic light to harden the photosensitive resin layer corresponding to the transparent portion of the original film.

Then, by dissolving the uncured photosensitive resin layer with a suitable solvent, a concave pattern faithful to the original drawing is formed on the base material.

[Problems to be Solved by the Invention] According to the conventional technology, even if image exposure is performed through an original film on a photosensitive resin letterpress material or an intaglio material, no visible change occurs in the photosensitive resin layer. . Therefore, which original film was exposed to which plate material?
It was also difficult to confirm whether the plate material had been exposed or not.

Therefore, a problem arises in that another original film is exposed in close contact with the exposed plate material.

In addition, in plate inspection work to confirm whether the obtained relief pattern or recessed pattern has been completed as specified after exposure and development, the quality of the fine colorless relief pattern or recessed pattern is judged. It is difficult to do so. Among these problems, in order to improve the difficulty of plate inspection work, by adding known dyes or pigments to the photosensitive resin layer, relief-like patterns or concave patterns (more precisely, photocuring of areas other than the concave areas) can be applied. The pattern (formed by the photosensitive resin layer) is colored to facilitate plate inspection. However, when the entire photosensitive resin layer is colored, the dye or pigment contained in the uncured area is eluted into the developer during development, resulting in significant coloration of the developer. Therefore, problems such as the used developer contaminates the environment, contaminates the developing device, and contaminates the working environment occur.

The present inventors devised this technology in view of the various shortcomings of the prior art, and the purpose is to improve plate-making workability by coloring and visualizing only the exposed area when exposing an image through an original film. An object of the present invention is to provide a photosensitive resin letterpress material and an intaglio material from which the following can be obtained.

[Means for Solving the Problems] That is, the present invention provides a photocurable photosensitive resin layer of C containing a dye precursor that forms a dye upon irradiation with actinic rays on a base material. This relates to a photosensitive resin letterpress material or a photosensitive resin intaglio material that is provided on a base material with a photocurable photosensitive resin layer containing a dye precursor that forms a dye upon irradiation with actinic rays. be.

According to the present invention, when exposed through the original film,
A pigment is formed and colored only in the area irradiated with actinic rays, that is, in the photocured area. Therefore, the exposed pattern can be easily confirmed. In addition, the quality of the relief pattern or concave pattern after development can be visually confirmed very easily. Furthermore, since the developer from which the uncured portion is eluted is colorless or hardly colored, environmental pollution can be avoided.

Examples of the dye precursor of the present invention that forms a dye upon irradiation with actinic rays include G and H.

Edited by BroWn, “photochromi sm” (T
echniques of chemistry
Vol. I[I], spiro[2H-1-benzopyran-2,
2′-indoline], spiroindolinonaphthopyran,
Spiro[2H-1-benzopyran-2,2-benzothiazoline], Spiro[2H-1-benzopyran-2,2
'-Benzoxazoline], spiropyran compounds such as aza-spiroindolinopyran, leuco forms of triarylmethane dyes such as leuco crystal violet and leucomalachite green, α,ω-bis(p-dimethylaminophenyl) polyenes, etc. Examples include cationic polymethine, thioindigo derivatives such as perinaphthothioindigo, azo compounds such as azobenzene with various substituents, and benzyl viologen derivatives. However, in the present invention, it is preferable to use spiropyran compounds and leuco forms of triarylmethane dyes that develop more vivid colors.

The additive tl[i of the photochromic dye precursor is preferably in the range of 0.001 to 5% by weight based on the entire photosensitive resin. If the amount added is less than 0.001% by weight, the amount of coloring in the light irradiated area is small, so there is no sufficient effect, and if it is added in excess of 5% by weight, a significant portion of the irradiated actinic rays will be used to form pigments. As a result, the photocurability of the photosensitive layer often decreases significantly. A more preferable amount of the dye precursor to be added is 0.05 to 1% by weight. It is also possible to use two or more types of dye precursors in combination.

As the photocurable photosensitive resin of the present invention, all known ones can be used, and specific examples include the following.

Photosensitive resins made by blending binder resins such as polyamide, partially saponified polyvinyl acetate, and cellulose derivatives with photopolymerizable or photoadditive compounds and appropriate photosensitizers, and photopolymerizable elastomers such as polyurethane and synthetic rubber. or a photosensitive resin containing a photoadditive compound and an appropriate photosensitizer; It is coated with a photocurable epoxy resin containing a catalyst that generates Lewis acid.

These photosensitive resins are used by forming a photosensitive resin layer on a base material such as a metal plate made of steel, aluminum or copper, or a cylinder roller, or a plastic film or sheet made of polyester, polyamide, polypropylene or the like.

For letterpress materials, the thickness of the photosensitive resin layer is preferably 100μ or more, more preferably 200μ or more. In the case of an intaglio material, the thickness is preferably 5μ or more, more preferably 10μ or more.

A known example of applying a photosensitive resin containing a photochromic dye precursor to a printing plate is JP-A-55-5535. In this known example, the thickness of the photosensitive layer is 0.1
The main target is planographic material with a thickness of ~5μ. Because the photosensitive layer is thin, it contains a large amount of dye precursor, and 2,4-dihydroxybenzaldoxime is used in combination to prevent so-called dark coloring, which occurs when the dye precursor develops color while stored in a dark place. I am proposing that. Also, JP-A-63-101
No. 50 discloses that an antioxidant such as hydroquinocyanate p-aminophenol is effective in preventing this dark color development. However, the addition of these stabilizers often also inhibits the photocuring reaction. This adverse effect is not so noticeable when the photosensitive layer is thin like a planographic material. However, letterpress materials and intaglio materials with thick photosensitive layers often have problems such as a significant decrease in photocurability at the bottom of the photosensitive layer.

However, according to the studies of the present inventors, n-octylthiol, n-nonylthiol, n-decylthiol, n-undecylthiol, n-dodecylthiol,
It has been found that the addition of thiol compounds such as thiophenol, benzylthiol, ethylene thioglycol, and thioglycerin can prevent dark coloration with almost no decrease in photosensitivity even when applied to letterpress and intaglio materials with thick photosensitive layers.

Although such thiol compounds are weak radical scavengers, they are effective in preventing dark reactions that occur gradually, and are thought to have very little adverse effect on radical reactions when irradiated with actinic light.

The amount of such a thiol compound added is preferably in the range of 0.05 to 5% by weight based on the total photosensitive resin. When the amount added is less than 0.05% by weight, the effect of preventing dark reactions is small, and when it exceeds 5% by weight, the decrease in photosensitivity often becomes noticeable. A more preferable amount of the thiol compound is 0.
．． The amount is 2 to 2% by weight. Two or more types of thiol compounds can also be used in combination.

Additionally, combining these thiol compounds with thiophosphite compounds such as tributyl trithiophosphite, triokdyl trithiophosphite, and dilauryl dithiobutyl phosphite in a range of 0.01 to 1% by weight can also have a synergistic effect. is recognized.

[Example] The present invention will be explained in more detail with reference to Examples below.

Example 1 Partially saponified polyvinyl acetate 100 with saponification degree of 75 mol%
Parts by weight were dissolved by heating at 60° C. in 150 parts by weight of a mixed solvent of ethanol/water = 50,150 (weight ratio). Next, 70 parts by weight of an addition reaction product of 1 mole of propylene glycol diglycidyl ether and 2 moles of acrylic acid as a photopolymerizable compound and 30 parts of diethylene glycol as a compatibilizer were added. Further, 2 parts by weight of dimethylbenzyl ketal as a photosensitizer and 0.2 parts by weight of crystal violet as a dye precursor were added and mixed with thorough stirring.

1 q of the photosensitive resin solution was cast onto a 250 μm thick steel substrate coated with an epoxy adhesive in advance so that the photosensitive layer had a dry thickness of 700 μm. this,
The material was placed in a hot air oven at 60° C. for 5 hours to remove the solvent and produce a letterpress material.

When a test negative film was vacuum-adhered onto the photosensitive layer of the letterpress material prepared in this manner and exposed for 2 minutes using an ultra-high pressure mercury lamp, only the exposed areas turned bright blue-purple in the shape of the original pattern. It developed color. Next, a spray type developing device containing tap water (Water W 30℃, spray pressure 5Kg)
/cm2) for 5 minutes, the uncured portions that were not colored were completely removed. In this way, a blue-purple relief was obtained that reproduced even the finest details of the original pattern on the steel substrate.

Example 2 100 parts by weight of alcohol-soluble polyamide "'amilan" CM-9000 manufactured by Toshishiku Co., Ltd. was mixed with ethanol/water = 8
80 parts by weight of a mixed solvent of 0/20 (weight ratio)
The mixture was heated and dissolved at ℃. Next, 50 parts by weight of an addition reaction product of 1 mole of ethylene glycol diglycidyl ether and 2 moles of methacrylic acid and 10 parts by weight of pentaerythritol triacrylate were added as photopolymerizable compounds. 5 parts by weight of dimethylbenzyl ketal as a photosensitizer and 1 part by weight of crystal violet as a dye precursor were added to the mixture and thoroughly stirred and mixed.

The obtained photosensitive resin solution was cast onto a 350 μm thick polyester film substrate coated with a polyester adhesive in advance so that the dry photosensitive layer had a thickness of 25 μm. This was placed in a hot air oven at 100°C for 5 minutes to dry it.

A positive film for testing was vacuum-adhered onto the photosensitive layer of the intaglio material obtained in this way, and a chemical lamp was used to heat the film for 90 minutes.
When exposed for seconds, only the exposed areas developed a bluish-purple color. Next, ethanol/water = 70/30 (1 weight
Brush type developing device containing developer solution (solution temperature: 30℃)
Developing was carried out for 15 seconds to obtain a concave pattern in which areas other than the concave portions were colored bluish-purple.

Example 3 Alcohol-soluble polyamide "7 Milan" CM-9000100 weight manufactured by Toshishiku Co., Ltd.) Xj part ethanol/water =
80' to 180 parts by weight in an 80/20 (weight ratio) solvent
The mixture was heated and dissolved at C. Next, 70 parts by weight of an addition reaction product of ethylene glycol diglycidyl ether and methacrylic acid was added as a photopolymerizable compound, 2 parts by weight of dimethyl benzyl ketal was added as a photosensitizer, and 0.15 parts by weight of leuco crystal violet was added as a dye precursor. 1 part by weight of thioglycerin as a dark coloring inhibitor were added and mixed thoroughly with stirring.

1 q of the photosensitive resin solution was cast onto a 250 μm thick polyester film substrate coated with a polyester adhesive in advance so that the dry thickness of the photosensitive layer was 600 μm. This was placed in a hot air oven at 60° C. for 4 hours to remove the solvent and produce a letterpress material.

A test negative film was vacuum-adhered onto the photosensitive layer of the letterpress material obtained in this way, and then exposed to an ultra-high pressure mercury lamp.
When exposed for one minute, only the exposed areas developed a bright blue-purple color in the shape of the original pattern. Then ethanol/
Spray type developing device containing developer with water = 85/15 (weight ratio) (liquid temperature 30℃, spray pressure 4KCI/Cm2)
When the film was developed for 7 minutes, the uncured areas that did not develop any color were completely removed, and a bluish-purple colored relief was obtained on the substrate in which even the finest details were reproduced.

Comparative Example 1 A letterpress material was produced under the same conditions as in Example 3 except that 1 part by weight of thioglycerin was not added.

This plate material and the letterpress material obtained in Example 3 were stored for 10 days at 40° C. and 60% relative humidity, and then taken out. As a result, the plate material of Example 3 showed no difference from the time at the start of the storage test, whereas the plate material to which thioglycerin was not added developed a pale bluish-purple color throughout.
A darkly colored spot was observed.

Example 4 Acrylonitrile was added to both ends of polyoxyethylene with a number average molecular weight of 1600, and this was reduced with hydrogen to obtain 1q
55 parts by weight of an equimolar salt of α,ω-diaminopolyoxyethylene and adipic acid, 25 parts by weight of ε-prolactam, and 20 parts by weight of a salt of hexamethylene diamine and adipic acid.
The heavy end portion was polymerized under normal conditions to obtain polyamide.

100 parts by weight of this polyamide, ethanol/water = 60
/40 (weight ratio) was dissolved in 150 parts by weight of a mixed solvent at 80°C. Next, glycidyl methacrylate was dissolved in 150 parts by weight of a mixed solvent of
Parts by weight were added and reacted at 80°C for 1 hour to introduce methacryloyl groups at the ends of the polyamide. Then, 40 parts by weight of an addition reaction product of propylene glycol diglycidyl ether and acrylic acid and 20 parts by weight of glycerol dimethacrylate were added as photopolymerizable compounds. In addition, 20 parts by weight of N-butylbenzenesulfonamide as a plasticizer, 3 parts by weight of dimethylbenzyl ketal as a photoinitiator, and 0 parts by weight of leuco crystal violet as a dye precursor.
．． 4 parts by weight, 0.5 parts by weight of n-dodecylthiol as a dark coloring inhibitor, and 0.5 parts by weight of trioctyltrithiophosphite.
1 part by weight was added and thoroughly stirred and mixed.

The photosensitive resin solution thus obtained was cast onto a 20 μm thick steel substrate coated with an epoxy adhesive in advance so that the photosensitive layer would have a thickness of 400 μm after drying. This was placed in a hot air oven at 60° C. for 3 hours to remove the solvent. In this way, the letterpress material, which was decorated with a steel substrate, was removed.

This letterpress material was stored for two weeks under the conditions of 40'C1 relative humidity of 80%, but no color development due to dark reaction was observed.

Next, the same negative film as in Example 3 was vacuum-adhered to the photosensitive layer and exposed to a chemical lamp for 5 minutes, and the exposed area developed a bright blue-purple color. Next, development was carried out for 1 minute using a brush-type developing device (water temperature: 25° C.) filled with running water. In this way, 1q of relief patterns colored bluish-purple were formed on the steel substrate. When this relief pattern was observed, it was easily determined that even the minute parts were well reproduced.

Example 5 Partially saponified polyvinyl acetate 100 with saponification degree of 80 mol%
Parts by weight were dissolved in 150 parts by weight of a mixed solvent of ethanol/water = 50,150 (weight ratio) by heating at 60'C. Next, 80 parts of 2-hydroxyethyl methacrylate and 2 parts of ethylene glycol dimethacrylate were added as photopolymerizable compounds.
0 parts by weight were added. In addition, 5 parts by weight of benzophenone as a photosensitizer and 1,3,3-trimethylspiro[indoline-2,3=-[31-1] as a dye precursor.
-naphtho[2,1-b] (1,4)oxazine] was added in an amount of 1 part by weight, and n-octylthiol as a dark reaction inhibitor was added in an amount of 1 part by weight, and the mixture was sufficiently stirred and mixed.

The resulting photosensitive resin solution was applied onto a 400 μm thick aluminum substrate coated with epoxy adhesive in advance so that the photosensitive layer would have a thickness of 30 μm after drying, and heated in a hot air oven at 80°C. It was dried for 10 minutes to produce an intaglio material.

This intaglio material was stored for one month under conditions of 30° C. and 80% relative humidity, but no color development due to dark reaction was observed. Thereafter, when a test positive film was vacuum-adhered to the photosensitive layer and exposed to a chemical lamp for 1 minute, only the exposed areas developed a pink color. Next, a brush type ring filled with tap water @
Developed in a device (water temperature 25°C) for 20 seconds, and the concave pattern except for the concave areas was colored pink. This is 1q.

[Effects of the Invention] Since the photosensitive resin letterpress material or intaglio material according to the present invention is constructed as described above, only the exposed area develops color faithfully to the original image, so the printed image can be clearly visually confirmed, and plate making is easy. Work efficiently.

In addition, the relief pattern or concave pattern, which has a development speed of 1q, is colored, making plate inspection work to determine its quality extremely easy. Roughly speaking, only the exposed and hardened portions are colored, so even if the uncured portions are developed and removed, the developer will not be colored, and there is no concern about environmental pollution caused by the developer.

Claims (1)

[Scope of Claims] 1. A photosensitive resin letterpress material comprising a photocurable photosensitive resin layer containing a dye precursor that forms a dye upon irradiation with actinic rays on a base material. 2. A photosensitive resin intaglio plate comprising a photocurable photosensitive resin layer containing a dye precursor that forms a dye upon irradiation with actinic rays on a base material. 3. The photosensitive resin letterpress material according to claim 1, which contains a thiol compound in the photosensitive resin layer. 4. The photosensitive resin intaglio material according to claim 2, wherein the photosensitive resin layer contains a thiol compound.