JP2621417B2 - Photosensitive resin letterpress and intaglio materials - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a photosensitive resin relief printing material and an intaglio printing material.

2. Description of the Related Art A photosensitive resin letterpress or intaglio material obtained by providing a photocurable photosensitive resin layer on a base material such as a metal or plastic film is widely used.

Among them, the letterpress material is to directly or indirectly adhere the original film having the negative pattern to the photosensitive resin layer, and then to irradiate actinic rays to cure the photosensitive resin layer corresponding to the transparent portion of the original film. . Then, the uncured photosensitive resin layer corresponding to the opaque portion of the original film is eluted with an appropriate solvent such as alcohol, alcohol / water or water, so that a relief pattern faithful to the original film is formed on the substrate. Things.

On the other hand, in the intaglio material, after the original film having the positive pattern is directly or indirectly adhered to the photosensitive layer, the photosensitive resin layer corresponding to the transparent portion of the original film is cured by irradiation with actinic rays.

Next, the uncured photosensitive resin layer is eluted with an appropriate solvent to form a concave pattern faithful to the original drawing on the base material.

[Problems to be Solved by the Invention] According to the conventional technology, even if image exposure is performed on a photosensitive resin relief printing plate or an intaglio printing plate through an original film, there is no visible change in the photosensitive resin layer. . Therefore, it has been difficult to confirm which original film was exposed to which plate material, and further, whether the plate material was exposed. For this reason, there is a problem in that another original film is brought into close contact with the exposed plate material and exposed.

In addition, after the exposure and the development are completed, the quality of the colorless fine relief-shaped pattern or the concave pattern is also determined in the plate inspection work for checking whether the obtained relief-shaped pattern or the concave pattern is completed to a predetermined one. It is difficult to do. Among these problems, in order to improve the difficulty of plate inspection work, a known dye or pigment is added to the photosensitive resin layer to form a relief-shaped pattern or a concave pattern (exactly, a light-curing pattern other than the concave part). (Patterns formed by the photosensitive resin layer thus formed) to facilitate plate inspection. However, when the entire photosensitive resin layer is colored, the dye or pigment contained in the uncured portion at the time of development is eluted into the developer, so that the developer is significantly colored. Therefore, problems such as the contamination of the used developer with the environment, the contamination of the developing device, and the contamination of the working environment have occurred.

The present inventors have been created in view of the drawbacks of the prior art, the purpose is, when the image is exposed through the original film, only the exposed portion is colored and visualized,
An object of the present invention is to provide a photosensitive resin relief printing plate material and an intaglio printing plate material capable of obtaining extremely excellent plate making workability.

[Means for Solving the Problems] That is, in the present invention, a photocurable photosensitive resin layer containing a dye precursor and a thiol compound which forms a dye by irradiation with actinic light is provided on a substrate. The invention relates to a photosensitive resin relief printing plate material or an intaglio photosensitive resin material provided with a photocurable photosensitive resin layer containing a dye precursor that forms a dye upon irradiation with actinic rays on a substrate. It is.

According to the present invention, when exposed through the original film, only the portion irradiated with the actinic ray, that is, the photocured portion, is formed by coloring and coloring. Therefore, the exposed pattern can be easily confirmed. Further, the quality of the relief pattern or the concave pattern after the development can be visually checked very easily. Further, since the developer from which the uncured portion has eluted is colorless or hardly colored, environmental pollution can be avoided.

Examples of the dye precursor of the present invention that forms a dye by irradiation with actinic rays include, for example, GH Brown, “photo
chromism "(Techniques of Chemistry Vol.III), which has spiro [2H
-1-benzopyran-2,2'-indoline], spiroindolinononaphthopyran, spiro [2H-1-benzopyran-2,2'-benzothiazoline], spiro [2H-1-benzopyran-2,2'-benzo Oxazoline], spiropyran compounds such as Atherspirindolinopyran, leuco crystal violet, leuco bodies of triarylmethane dyes such as leucomalachite green, and cationic polymethine dyes such as α, ω-bis (p-dimethylaminophenyl) polyene Thioindigo derivatives such as perinaphthothioindigo, azo compounds such as azobenzene having various substituents, and benzyl viologen derivatives are also known, and polymers containing these compounds can also be mentioned. According to the present invention, a spin that produces a clearer color is provided. Pyran compounds, preferably used leuco of triarylmethane dyes.

The addition amount 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 effect is not sufficient because the amount of coloring in the light-irradiated portion is small, and if it exceeds 5% by weight, a considerable portion of the irradiated active light is consumed for the formation of the dye. For this reason, the photocurability of the photosensitive layer is often significantly reduced. A more preferred amount of the dye precursor is
It is 0.05 to 1% by weight. Two or more dye precursors can be used in combination.

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

Polyamide, partially saponified polyvinyl acetate and a photosensitive resin in which a photopolymerizable or photoadditive compound and a suitable photosensitizer are blended with a binder resin such as a cellulose derivative,
Suitable for photopolymers such as polyurethanes and synthetic rubbers containing photopolymerizable or photoadditive compounds and a suitable photosensitizer, unsaturated polyester, unsaturated polyurethane, unsaturated acrylic, etc. Examples thereof include a photosensitive resin containing a sensitizer, a photocurable epoxy resin containing a catalyst that generates a Lewis acid by light, and the like.

These photosensitive resins include metal plates or cylinder rolls of steel, aluminum, copper, etc., polyester,
It is used by forming a photosensitive resin layer on a base material such as a plastic film or sheet such as polyamide or polypropylene.

The thickness of the photosensitive resin layer is preferably 100 μm or more, more preferably 200 μm or more, in the relief printing plate material. In the case of an intaglio material, it is preferably 5 μ or more, more preferably 10 μ
That is all.

JP-A-55-5535 discloses a known example of applying a photosensitive resin containing a photochromic dye precursor to a printing plate. In this known example, the thickness of the photosensitive layer is 0.1 to 5 μm.
Mainly for planographic materials. Because the photosensitive layer is thin, it contains a large amount of the dye precursor, and in order to prevent the so-called dark coloring in which the dye precursor develops color during storage in a dark place, it is necessary to use 2,4-dihydroxybenzaldoxime in combination. is suggesting. In JP-A-63-10150,
It discloses that an antioxidant such as hydroquinone or p-aminophenol is effective in preventing this dark coloration. However, the addition of these stabilizers often also inhibits the photocuring reaction. This adverse effect does not appear so remarkably when the photosensitive layer is thin like a lithographic material. However, a relief printing material or an intaglio printing material having a thick photosensitive layer often causes a problem that the photocurability at the bottom of the photosensitive layer is remarkably reduced.

However, according to the study of the present inventors, n-octylthiol, n-nonylthiol, n-decylthiol, n-undecylthiol, n-dodecylthiol,
It was found that the addition of a thiol compound such as thiophenol, benzyl thiol, ethylene thioglycol, thioglycerin or the like can hardly reduce the photosensitivity and prevent dark coloring even when applied to letterpress materials or intaglio materials having a thick photosensitive layer. Such a thiol compound is a weak radical scavenger, but works effectively to prevent dark reactions that occur gradually,
It is considered that the adverse effect on the radical reaction upon irradiation with actinic rays is extremely small.

The addition amount of such a thiol compound is desirably in the range of 0.05 to 5% by weight based on the entire photosensitive resin.
When the addition amount is less than 0.05% by weight, the effect of preventing dark reaction is small, and when it exceeds 5% by weight, the decrease in photosensitivity often becomes remarkable. More preferable addition amount of the thiol compound is 0.2 to
2% by weight. Two or more thiol compounds can be used in combination.

A synergistic effect is also observed when a thiophosphite compound such as tributyltrithiophosphite, trioctyltrithiophosphite, or dilauryldithiobutylphosphite is used in combination with these thiol compounds in the range of 0.01 to 1% by weight.

[Examples] Hereinafter, the present invention will be described more specifically with reference to Examples.

Example 1 100 parts by weight of an alcohol-soluble polyamide "Amilan" CM-9000 manufactured by Toray Industries, Inc. was dissolved by heating at 180 ° C in 180 parts by weight of a solvent of ethanol / water = 80/20 (weight ratio). Next, 70 parts by weight of an addition reaction product of ethylene glycol diglycidyl ether and methacrylic acid as a photopolymerizable compound was added,
Further, 2 parts by weight of dimethylbenzyl ketal as a photosensitizer and leuco crystal violet as a dye precursor
0.15 parts by weight and 1 part by weight of thioglycerin as a dark color-developing agent were added and mixed well with stirring.

The obtained photosensitive resin solution was cast on a 250 μm-thick polyester film substrate to which a polyester-based adhesive was previously applied so that the dried 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, thereby producing a relief material.

A negative film for test was vacuum-adhered on the photosensitive layer of the relief material obtained in this way, and exposed for 2 minutes with an ultra-high pressure mercury lamp. Only the exposed portions became bright blue-violet in the original pattern. It developed color. Next, when developed with a spray type developing device (liquid temperature 30 ° C., spray pressure 4 kg / cm ² ) containing a developing solution of ethanol / water = 85/15 (weight ratio) for 7 minutes, uncolored uncured The part was completely removed, and a blue-violet colored relief reproduced on the substrate to a fine part was obtained.

Comparative Example 1 In Example 1, a relief material was produced under exactly the same conditions except that 1 part by weight of thioglycerin was not added.

The plate material and the relief plate material obtained in Example 1 were taken out after being stored at 40 ° C. and a relative humidity of 60% for 10 days.
As a result, no difference was observed between the plate material of Example 1 and the plate material at the start of the preservation test, while the plate material without the addition of thioglycerin developed a pale blue-purple color as a whole, and formed a deep spot color. The part which did was recognized.

Example 2 Acrylonitrile was added to both ends of polyoxyethylene having a number-average molecular weight of 600, and α,
55 parts by weight of an equimolar salt of ω-diaminopolyoxyethylene and adipic acid, 25 parts by weight of ε-caprolactam, and 20 parts by weight of a salt of hexamethylenediamine and adipic acid were polymerized under ordinary conditions to obtain a polyamide.

100 parts by weight of this polyamide is ethanol / water = 60/40
(Weight ratio) The mixture was heated and dissolved in 150 parts by weight of a mixed solvent at 80 ° C. Next, 2 parts by weight of glycidyl methacrylate was added and reacted at 80 ° C. for 1 hour to introduce a methacryloyl group into the terminal of the polyamide. Thereafter, 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. Further, 20 parts by weight of N-butylbenzenesulfonamide as a plasticizer, 3 parts by weight of dimethylbenzyl ketal as a photoinitiator, 0.4 parts by weight of leuco crystal violet as a dye precursor, and 0.5 parts by weight of n-dodecylthiol as a dark color inhibitor And 0.1 part by weight of trioctyltrithiophosphite were added and thoroughly mixed by stirring.

The photosensitive resin solution thus obtained was cast on a steel substrate having a thickness of 20 μm to which an epoxy adhesive was previously applied so that the thickness of the photosensitive layer after drying was 400 μm. This was placed in a 60 ° C. hot air oven for 3 hours to remove the solvent. In this way, a relief material lined with a steel substrate was obtained.

This letterpress material was stored at 40 ° C. and a relative humidity of 80% for 2 weeks, but no color development due to dark reaction was observed. Next, the same negative film as in Example 1 was vacuum-contacted to the photosensitive layer and exposed to a chemical lamp for 5 minutes. The exposed portion developed a bright blue-violet color. Next, development was performed for 1 minute with a brush type developing device (water temperature: 25 ° C.) filled with tap water. In this way, a relief pattern colored blue-violet on the steel substrate was obtained. When this relief pattern was observed, it was easy to determine that the fine pattern was well reproduced.

Example 5 100 parts by weight of partially saponified polyvinyl acetate having a saponification degree of 80 mol% was mixed with a mixed solvent of ethanol / water = 50/50 (weight ratio) 150
The mixture was heated and dissolved at 60 ° C in parts by weight. Next, 80 parts by weight of 2-hydroxyethyl methacrylate and 20 parts by weight of ethylene glycol dimethacrylate were added as the photopolymerizable compound. Further, 5 parts by weight of benzophenone as a photosensitizer and 1,3,3-trimethylspiro [indoline-2,3 '-[3H] -naphtho [2,1-b] (1,4) as a dye precursor Oxazine] was added in an amount of 1 part by weight, and n-
1 part by weight of octyl thiol was added and thoroughly stirred and mixed.

The obtained photosensitive resin solution was applied on a 400 μm-thick aluminum substrate to which an epoxy-based adhesive had been applied in advance so that the thickness of the photosensitive layer after drying was 30 μm. After drying for minutes, an intaglio material was prepared.

This intaglio material was stored for one month at 30 ° C. and a relative humidity of 80%, but no color formation due to dark reaction was observed. Thereafter, when a positive film for test was brought into close contact with the photosensitive layer under vacuum and exposed for 1 minute with a chemical lamp, the exposed portion developed a pink color only in the exposed portion. Subsequently, development was performed for 20 seconds with a brush-type developing device (water temperature: 25 ° C.) containing tap water to obtain a concave portion pattern in which portions other than the concave portions were colored pink.

[Effects of the Invention] Since the photosensitive resin relief printing plate or intaglio printing material according to the present invention is configured as described above, only the exposed portions faithfully develop the color of the original image, so that the printed image can be clearly visually confirmed and the plate making operation can be performed. Can be performed efficiently. In addition, the relief pattern or the concave pattern obtained after development is colored, making it extremely easy to perform plate inspection for judging the quality. Further, since only the exposed and cured portions are colored, the developing solution is not colored even if the uncured portions are removed by development, and there is no concern about environmental pollution by the developing solution.

Claims (2)

(57) [Claims] 1. A photosensitive resin relief plate comprising a substrate and a photocurable photosensitive resin layer containing a dye precursor and a thiol compound which form a dye upon irradiation with actinic rays. 2. A photosensitive resin intaglio material comprising a substrate and a photocurable photosensitive resin layer containing a dye precursor and a thiol compound which form a dye upon irradiation with actinic rays.