JPS609800A - Direct-printing waterless planographic original plate - Google Patents

Abstract

PURPOSE:To prevent printing plate performance from being lowered with time, by sequentially providing a photosensitive resin layer and a silicone rubber layer in lamination on a specified base. CONSTITUTION:The base on which the photosensitive resin layer and the silicone rubber layer are sequentially provided is provided with a covering layer on a rubber elastic body, which covering layer comprises a rubber component and is resistant to solvents. The rubber component in the covering layer may be, for example, a natural rubber or a synthetic rubber (polybutadiene rubber, nitrile rubber, urethane rubber, a polyamide elastomer or the like), which is used singly or in combination of two or more, and is used in the state of being mixed or cross-linked with a thermosetting polymer binder. The most preferable covering layer is one comprising the same rubber component as that in the rubber elastic body, in which case the adhesion of the layer to the rubber elastic body is enhanced. In addition, when the covering layer comprising the rubber component and the polymer binder cross-linked with each other is used, solvent resistance is enhanced, and the range of application of developing liquids at the time of forming the printing plate is widened.

Description

[Detailed description of the invention] Technical field The present invention relates to a waterless lithographic printing plate blank for reprinting.

An example of a waterless planographic printing plate suitable for printing directly onto a printing material without using a blanket using a prior art planographic printing plate as it is is shown in Japanese Patent Application Laid-Open No. 57-20740. Here, an intermediate layer is provided on a rubber elastic body, and a waterless lithographic printing original plate for overprinting is formed by laminating a photosensitive resin layer and a silicone rubber layer in this order, and the original plate is exposed to light.
The rubber elastic body provided under the printing layer of the printing plate obtained by development plays the role of a blanket in offset printing and provides good ink transferability. This intermediate layer is effective as a barrier for the photosensitive resin component, prevents economical deterioration of the performance of the first plate, and makes it possible to obtain a practical printing plate blank for use in net printing. are using.

In order to form such an intermediate layer between the rubber elastic body and the photosensitive resin layer, for example, a molded synthetic resin film may be bonded onto the support using an adhesive, or an unvulcanized synthetic resin film may be bonded onto the support. Examples include a method of integrally molding with a rubber layer that serves as a support, a method of extrusion lamination on a rubber layer that serves as a support, or a method of coating a synthetic resin film with a substance having rubber elasticity after dissolving it in a solvent. However, it requires skilled techniques. Also.

It is difficult to form a good intermediate layer due to problems such as wrinkles in the film and inclusion of air bubbles. Furthermore, it is difficult to maintain good adhesion between the rubber elastic body and the film.

OBJECT OF THE INVENTION The present inventors have proposed a method for easily obtaining a good intermediate layer, and a method by which this intermediate layer is effective as a barrier for a photosensitive resin component and prevents deterioration of plate performance over time. figure,
It has good solvent resistance against developing solutions, ink solvents, cleaning agents, etc., and serves as a barrier to the solvent to the underlying comb elastic body, and also has excellent adhesive properties with the comb elastic body and photosensitive resin component. As a result of intensive studies to obtain a good intermediate layer, we have arrived at the present invention described below.

Structure of the Invention Namely 9 The present invention includes a comb component on a rubber elastic body,
On a support provided with a coating layer having solvent resistance,
This invention relates to a direct 1J waterless lithographic printing plate precursor, characterized in that it is formed by laminating a photosensitive resin layer and a silicone comb layer in this order.

Examples of the material for the rubber component of the coating layer of the present invention include, but are not limited to, the following.

Natural rubber and synthetic rubber include polybutadiene rubber. Examples include styrene-butadiene rubber, epichlorohydrin rubber, nitrile rubber, acrylic rubber, butyl rubber, urethane rubber, polyester elastomer, polyamide elastomer, and polyether esteramide elastomer.

As for rubber hardness, J Engineering S K 6301-1975
It is preferably 90 or less, more optimally 85 or less, according to the Spr IJ 2-g type doll testing machine shown in . If the coating layer contains more than 90, it is difficult to obtain a sufficient effect when printing the rubber elasticity of the rubber elastic body through the coating layer. These rubber components may be used alone or in combination of two or more. Furthermore, these rubber components are mixed with a polymer binder or crosslinked before use.

A thermosetting resin is preferred as the polymer binder.

The most preferable coating layer is one that contains the same type of rubber component as the underlying rubber elastic body, so that the adhesion to the rubber elastic body is strengthened.

Furthermore, by forming a coating layer in which the rubber component and the polymer binder are crosslinked, the solvent resistance is significantly improved, and the application of the developing solution during printing plate production is widened. In addition, it can be widely applied to various inks, ink solvents, ink cleaning agents, etc.

Solvent resistance here refers to 9. For example, when measuring mass change in an immersion test, toluene solvent is used at a temperature of 26 ± 2 °C.
The mass change rate of a test piece having the coating layer on a rubber elastic body lined with an aluminum plate on one side under conditions of 15 minutes or less, preferably 10 percent or less. If it is more than 15%, the rubber elastic body will swell depending on the developing solution used when making the printing plate, making it impossible to obtain a printing plate with good image reproducibility. Also, image distortion due to ink or ink solvent during printing.

In addition, the ink cleaning agent used to remove the ink from the printing plate may cause the image to become distorted.

The thickness of the coating layer is usually 0.5 μm or more.

If it is less than 0.5μ, it will not act as a barrier for photosensitive compositions containing low molecular weight components, it will be difficult to prevent changes in photosensitive properties over time, and no barrier effect against solvents can be expected. Also, if the rubber hardness of the rubber elastic body is equal to or higher than the rubber hardness of the covering layer, the thickness may be increased, but if the rubber hardness of the rubber elastic body is smaller than the rubber hardness of the covering layer, it may not be necessary. If the thickness is too thick, the rubber elasticity of the rubber elastic body will not have any effect through the coating layer, which is not preferable.

In order to achieve the object of the present invention, it is practically preferable that the coating layer has a thickness of 1 to 50 microns.

To form such a coating layer on a rubber elastic body,
The coating composition is melted or dissolved in a suitable solvent,
Marit Zoe, Curtain Flow.

Technically speaking, coating can be done using a normal coater such as a reverse roll, gravure roll, or X-P bar coater, or a rotary coating device such as Whaler.

It is also preferable from the viewpoint of adhesion to the rubber elastic body. Furthermore, the adhesive force can be increased by applying the rubber elastic material on a matted surface. By using such a coating method, it is possible to fill in defects such as irregularities in the underlying rubber elastic body.

Materials for the rubber elastic body used in the present invention include natural rubber, and synthetic rubbers include polyimprene rubber, polybutadiene rubber, styrene-butadiene rubber, nitrile rubber,
Acrylic rubber, butyl rubber.

Nibchlorohydrin rubber, urethane rubber, polyester elastomer, polyamide elastomer.

Examples include polyether ester amide elastomer. The rubber hardness of these rubber elastic bodies is J.
It is preferably 90 or less, more optimally 85 or less, according to the A-type spring type hardness tester shown in Japanese Patent Application No. K 6301-1975. Anything over 90 does not play the role of a blanket in offset printing and does not provide good ink transfer properties.

The thickness of the rubber elastic body is usually about 0.01 to 5 mm. Also, to give the rubber elastic body the shape retention required for printing plates.

A metal plate such as an aluminum plate or an iron plate, a plastic film, etc. can also be provided under the rubber elastic body.

The photosensitive resin layer is a layer that has the property of being photoinsolubilized or pre-solubilized by irradiation with active light. This layer is uniformly coated on the coating layer, and its thickness is arbitrary as long as it is in close contact with the coating layer, but preferably 1mm thick.
μ or less, and those of 50 μ or less are more useful.

If necessary, an anchor coat layer can be provided between the coating layer and the photosensitive resin layer in order to improve the adhesion between the photosensitive resin layer and the coating layer or to prevent halation.

Among the photosensitive resin layers used in the present invention, the photo-insolubilizable ones include those listed below.

(1) Polyfunctional monomers, oligomers, etc. having two or more unsaturated groups in one molecule are mixed into a suitable polymer binder.

Typical photopolymerizable groups include acryloyl group, methacryloyl group, acrylamide group, maleate ester group, allyl group, vinyl ether group, vinyl thioether group, vinylamine group, glycidyl group, acetylenically unsaturated group, etc. .

(2) A mixture of a photosensitive compound such as an aromatic diazo compound with a suitable polymer binder.

In addition, examples of the pre-dissolved photosensitive resin layer used in the present invention include those obtained by mixing diazo compounds with inorganic salts, complexes with organic acids, quinone diazides, etc. with appropriate polymer binders. .

The silicone rubber layer of the present invention has a thickness of 05 to 100μ.

Preferably it has a thickness of 1 to 50μ. Useful silicone rubbers are obtained by sparsely crosslinking linear diorganopolysiloxanes having molecular weights in the hundreds of thousands. Typical silicone rubbers have the following silicone units.

Here, n is an integer of 2 or more. R, R' have 1 or more carbon atoms
20 alkyl, alkenyl, aryl or cyanoalkyl groups. h9. Cavinyl, phenyl, vinyl halide, phenyl halide, 40% or less of the total R, R'. It is preferable that R and R' have a methyl group at 60 or more. Such 9-silicone rubber can be sparsely crosslinked by adding organic peroxides, but by using silicone rubber (RTV, LTV) that undergoes condensation type crosslinking,
A more preferable silicone rubber layer is obtained.

A protective film can also be laminated on the surface of the silicone rubber layer forming the surface of the waterless lithographic printing plate blank for litho printing constructed in this manner. Useful protective films are transparent and capable of transmitting ultraviolet light.

Examples of materials having a thickness of 100μ or less, preferably 10μ or less include polyethylene, polypropylene, polyvinyl chloride, and polyvinylidene chloride.

polyvinyl alcohol, polyethylene terephthalate,
Films such as cellophane can be used.

Effects of the Invention The coating layer of the waterless planographic printing plate blank for litho printing obtained as described above can be obtained by a simple manufacturing device and a technically easy coating method. This makes it possible to provide a coating layer that has good adhesion to the underlying rubber elastic body. In addition, the presence of a coating layer containing a rubber component and having solvent resistance is effective as a barrier for the photosensitive resin component, and not only prevents deterioration of plate performance over time, but also prevents the plate from deteriorating over time. The developer solution can be widely applied, and it becomes possible to use an inexpensive developer solution for automatic processors that does not require explosion-proof measures. It can also be widely applied to inks and ink solvents.

Furthermore, it becomes possible to use an ink detergent that has good ink cleanability but swells the rubber elastic body, and a waterless lithographic printing plate blank for litho printing with greatly improved practicality can be obtained.

Applications Using the waterless lithographic printing plate blank of the present invention, for example, 1
It is also possible to print on printing materials having a rough surface such as unevenness based on fibers such as paper, or hard printing materials such as synthetic resin films and sheets, metals, ceramics, and glass.

The present invention will be specifically explained below using examples, but the present invention is not limited to these examples in any way.

Example 1 0.26 mm thick on a 0.24 mm thick aluminum plate
.

A nitrile rubber layer with a rubber hardness of 70 (Shore A) is provided, and a solid content solution having the following composition (the solvent is methyl ethyl ketone/n-butyl alcohol = 872
) and dried in hot air at 160°C for 5 minutes to a thickness of 10
A coating layer of μ was provided.

(a) Nitrile rubber layer adhesion pole 1072. J(EI
(manufactured by Zeon) 20 parts by weight (b) Isobutylated melamine resin "r, -125-6
0'' (manufactured by Dainippon Ink & Chemicals) 80 parts by weight A substrate having this coating layer was immersed in a toluene solvent at 23° C. for 1 minute, and the mass change rate was 1%.

On top of this coating layer, a phenol novolac resin with a degree of esterification of 45% (manufactured by Sumitomo Bakelite: Sumiresin PR5) is applied.
A solution of 20% by weight of naphthoquinone-1,2-diazide-5-sulfonic acid ester (molecular weight: about 1300) of 0235) was applied.

It was dried in hot air at 100°C to form a photosensitive resin layer with a thickness of 2.5 μm. On top of this, a 0.5 weight ratio Isovar E (manufactured by Esso) solution of di-n-butoxy bis(acetylacetonato) titanium (manufactured by Nippon Kagaku Sangyo: Naseemu Ti) was applied and dried in hot air at 120°C. , an adhesive layer with a thickness of 0.2 μm was provided. Furthermore, a 20% by weight Isopar E solution of a silicone rubber composition having the following composition was applied thereon and dried in hot air at 105°C to form a silicone rubber layer with a thickness of 5μ. -0 (a) Polydimethylsiloxane (molecular weight approximately 80,000).

○H groups at both ends) 100 parts by weight (b) Methyltriacetoxysilane 5 heavy Ji parts (
C) Dibutyltin acetate 0.2 parts by weight A negative film was applied to the printing plate master plate obtained as above and brought into close contact under reduced pressure. Second exposure.

Ethyl calpitol/butyl calpitol-17 on the plate
When rubbed lightly with a cotton 13 pad impregnated with a mixed solvent of 1 (weight ratio), the exposed areas were easily removed and the coating layer was exposed, while the silicone rubber layer remained firmly in the unexposed areas. Finally, we obtained a printing plate that faithfully reproduced the negative film. The photosensitive characteristics of this printing original plate did not practically change even after being stored at room temperature for 1 month or stored at 50° C. for 7 days after production.

A test was conducted in which the obtained printing plate was printed on an aluminum plate using a direct printing machine that prints by rotating a cylinder with one plate attached, and the results showed a sharp image with good ink coverage. A printed matter was obtained. In addition, even when the ink on the printing plate was wiped off with toluene solvent after printing, the nine images did not deteriorate.

Comparative Example 1 Nitrile latex "Nirapol 1571" (manufactured by Nippon Zeon) was coated on the nitrile rubber layer lined with the aluminum plate of Example 1, and dried in hot air at 140°C for 5 minutes to form a 10μ thick coating. Layers were provided.

When this substrate was subjected to the same immersion test as in Example 1, the mass change rate was 16%.

14- A printing plate precursor was prepared in which a photosensitive resin layer, an adhesive layer, and a silicone layer were provided on the coating layer, and the other compositions were the same as in Example 1. After this original plate was exposed in the same way as the original plate of Example 1.

When rubbed with a cotton pad impregnated with the same developer (ethylcarpitol/butylcarpitol = 171 (weight ratio)), a printing plate with poor image reproducibility was obtained. Then, when a plate was made with ethyl alcohol, a printing plate with good image reproducibility was obtained, so when printing was carried out in the same manner as in Example 1, a printed matter similar to that in Example 1 was obtained, but after printing, the printing plate When cleaning the ink, toluene destroyed the image on the printing plate.

Example 2 A 27% weight solution of solids having the following composition was placed on the nitrile rubber layer lined with the aluminum plate of Example 1 (solvent: methyl ethyl ketone/n-butyl alcohol = 971)
was applied and dried in hot air at 140°C for 5 minutes to form a coating layer with a thickness of 20 μm.

(a) Nitrile rubber "Nirapol 1072J (manufactured by Nippon Zeon) 25 parts by weight (b) Isobutylated melamine resin "L-121-60
(manufactured by Dainippon Ink & Chemicals) 75 parts by weight A substrate having this coating layer was immersed in the same test as in Example 1, and the mass change rate was 4%.

A printing plate was prepared on this coating layer in the same manner as in Example 1, and when printing was carried out in the same manner as in Example 1, good printed matter was obtained. In addition, there was no deterioration of the nine images even during printing or when the ink on the printing plate was wiped off with toluene solvent after printing.

Comparative Example 2 A printing plate original plate exactly the same as in Example 1 was used, except that the coating layer in Example 1 was changed to a polyester film with a thickness of 3 μm (Lumirror" manufactured by Toshi), and the rubber adhesive was used as a laminated substrate. There were some wrinkles when the polyester film was put together.

Due to the presence of air bubbles, thickness unevenness occurred in 9 parts when the photosensitive layer, adhesive layer, and silicone layer were coated. When this original plate was subjected to 9M exposure in the same manner as in Example 1, a printing plate was obtained that had portions with poor image reproducibility due to thickness unevenness. When this printing plate was printed in the same manner as in Example 1, the polyester film of this printing plate was misaligned with the nitrile rubber layer below due to the shear stress between the printing plate and the substrate. Wrinkles occurred and good printed matter could not be obtained.

Patent applicant Higashi Shikikai Co., Ltd. ”-605

Claims (1)

[Claims] No water for overprinting, characterized in that a photosensitive resin layer and a silicone rubber layer are laminated in this order on a support comprising a rubber elastic body and a coating layer containing a rubber component and having solvent resistance. Planographic printing plate master plate.