JPS62183464A - Waterless lithographic printing plate for direct printing - Google Patents

Abstract

PURPOSE:To prevent the generation of cracks by incorporating a quinonediazide compd. and pulverized particles respectively having specified conditions into a photosensitive resin layer. CONSTITUTION:The photosensitive resin layer contains 100pts.wt. quinonediazide compd. and 10-150pts.wt. pulverized particles of which the average particle size is below the film thickness of the photosensitive resin layer and has the grain size distribution contg. <=20vol% pulverized particles having the particle size exceeding the total film thickness of the photosensitive resin layer and silicone rubber layer. The quinonediazide compd. is a phenolic or cresol formaldehyde resin introduced with naphthoquinone-1,2-diazide-5 or 5-sulfonic acid by an ester bond. Calcium carbonate, titanium oxide and silicon oxide are preferably used as the pulverized particles. The generation of the cracks is thereby prevented.

Description

Detailed Description of the Invention [Industrial Field of Application] The present invention provides a direct photosensitive resin layer formed by coating a photosensitive resin layer having a specific composition and a silicone rubber layer in this order on a support layer having rubber elasticity. It relates to waterless lithographic printing plates for printing.

[Prior Art] A waterless lithographic printing plate for direct printing is suitable for printing directly onto a printing material without using a blanket.

JP-A-56-78991, JP-A-57-2074
No. 0, JP-A No. 57-22242.

JP-A-57-124734, JP-A-59-152
This method is disclosed in Japanese Patent Application Laid-open No. 48, Japanese Patent Application Laid-open No. 131536/1980, and the like. Moreover, among these, the use of a quinonediazide compound as a photosensitive resin layer is disclosed.

Lithographic printing plates for direct printing using such a photosensitive resin layer are susceptible to impacts and compressive forces that are repeatedly applied between the printing material and the printing plate during printing, as well as deviations in circumferential speed such as occur in rotary printing presses. The photosensitive resin layer, which is inherently brittle, cracks due to shearing force, and the cracks cause the silicone rubber layer to break and form cracks.The cracks then accept ink, making it impossible to print faithful images. there were.

[Problems to be Solved by the Invention] An object of the present invention is to eliminate the various drawbacks of the prior art and provide a waterless lithographic printing plate for direct printing that is suitable for printing faithful images without generating cracks. There is a particular thing.

[Means for Solving the Problems] The object of the present invention is to provide waterless planographic printing for direct printing, in which a photosensitive resin layer and a silicone rubber layer are coated in this order on a support layer having rubber elasticity. In the plate, the photosensitive resin layer contains (a>100 parts by weight of a quinonediazide compound, (
b) Fine particles having a particle size distribution in which the average particle diameter is equal to or less than the thickness of the photosensitive resin layer, and 20% by volume or less of fine particles have a particle diameter exceeding the total thickness of the photosensitive resin layer and silicone rubber layer. A waterless lithographic printing plate for direct printing is characterized in that it contains 10 to 150 parts by weight.

The photosensitive resin layer in the present invention is made by dispersing fine particles selected from inorganic or organic substances in a quinonediazide compound as described above.

The quinonediazide compound used in the present invention includes:

Quinonediazides usually used in positive PS plates, Wipon plates, photoresists, etc.2 For example, pentuquinone-1,2-diazide-4 or 5-sulfonic acid and polyhydroxyphenyl, phenol-formaldehyde novolac resin, talesol-formaldehyde novolac resin Examples include esters of quinone diacids and polyfunctional compounds such as diisocyanates proposed in JP-A-56-80046. Particularly preferably used are phenol or cresol-formaldehyde resins into which naphthoquinone-1°2-diazide-5 or 4-sulfonic acid is introduced via an ester bond. Esterification rate with naphthoquinone-1,2-diazide-5 or 4-sulfonic acid is 20% or more, 6
It is preferably 5% or less. Esterification rate is 20%
If it is smaller, there will be less difference in solubility in the developing solvent between the exposed and unexposed areas. If it exceeds 65%.

It is inferior in terms of development speed of exposed areas and coating film formation of photosensitive layers.

The esterification rate is selected within the range of 20% or more and 65% or less depending on required performance such as sensitivity, developability, image reproducibility, etc.

The thickness of the photosensitive resin layer based on the above composition is 0.5~5.
A range of 0μ is preferred. If it is thinner than 0.5μ, defects such as pinholes are likely to occur.

Also 5. If it exceeds Oμ, the irradiated light will be diffusely reflected due to the added fine particles, resulting in poor image reproducibility and will also be economically disadvantageous.

Next, the fine particles to be dispersed and used in this photosensitive resin are arbitrarily selected from inorganic or organic substances.
APA-500> fine particles whose average particle diameter is less than the thickness of the photosensitive resin layer and which exceeds the total thickness of the photosensitive resin layer and silicone rubber layer account for 2 of the total fine particles.
It is necessary to have a particle size distribution that is less than or equal to 0% by volume.

If the average particle diameter exceeds the film thickness of the photosensitive resin layer, many irregularities will be formed on the surface of the photosensitive resin layer.

The irradiated light is diffusely reflected, resulting in defects such as loss of sharpness of the etch in the image area. Furthermore, if fine particles with a particle diameter exceeding the total film thickness of the photosensitive resin layer and silicone rubber layer have a particle size distribution exceeding 20% by volume of the total fine particles, the surface of the fine particles may be The covering silicone rubber layer is likely to peel off, and the exposed surface of the fine particles becomes an ink receiving area, causing problems such as staining the printing area.

Examples of fine particles used here include fine particles of inorganic substances such as calcium carbonate, magnesium carbonate, titanium oxide, silicon oxide, sodium silicate, calcium silicate, magnesium silicate, aluminum sulfate, barium sulfate, talc, mica, etc. Fine particles of organic substances such as resins, novolac resins, melamine resins, epoxy resins, cellulose, and wood flour are used, and one or more of these may be used selectively.

Particularly preferred fine particles are calcium carbonate.

Titanium oxide and silicon oxide are preferably used.

What is the mixing ratio of quinonediazide compound and fine particles?

Although it varies depending on the thickness of the photosensitive resin layer, printing method, required performance, etc., the latter is 1 part by weight for 100 parts by weight of the former.
It is preferable to use it in a range of 0 to 1501 ffi parts. If it is less than 10 parts by weight, no crack prevention ability will be exhibited, while if it is more than 150 parts by weight, image reproducibility will be poor. A more preferable range is 50 to 100 parts.

Necessary additives 1 such as pigments, dyes, and other resins can be added to the photosensitive resin layer within a range that does not impair its performance.

The silicone rubber preferably used in the present invention is a silicone rubber whose main component is a linear organic polysiloxane having the following repeating units and having a molecular weight of several thousand to several hundred thousand.

Preferably, (R is an alkyl group having 1 to 10 carbon atoms or) an engineering group, and 60% or more of R is a methyl group. ) This linear organic polysiloxane usually has a terminal hydroxyl group, and includes acetoxysilane, ketoximesilane,
A crosslinking agent such as an alkoxysilane is present, and if necessary, crosslinking is performed by heat treatment in the presence of a catalyst such as an organic tin compound, and used as a silicone rubber layer.

In addition, if necessary, a silicone rubber layer and a photosensitive resin layer,
Alternatively, a known silicone primer or silicone coupling agent layer may be provided between one layer for adhesion between the photosensitive resin layer and the support layer, or a known silicone primer or silicone coupling agent layer may be provided between the silicone rubber layer or the photosensitive resin layer. It is also effective to add agents.

The thickness of the silicone rubber layer, which is the ink repellent layer used in the present invention, is preferably 0.5 to 100 μm.

More preferably, those having a diameter of 1 to 50 μm are used.

The support used has rubber elasticity, such as polyether ester elastomer, polyether ester amide elastomer, butadiene-styrene rubber, butadiene-acrylonitrile rubber, butyl rubber, chloroprene rubber, natural rubber, and the like. The rubber elastic body preferably has a Shore A hardness of 90 or less. Thickness is usually 0.01~
5ITIIr1 is used.

These support layers with rubber elasticity are made of metal sheets made of aluminum, iron, etc., plastic films or sheets made of polyethylene terephthalate, polycarbonate, etc., in order to provide the shape retention required for printing plates. It is practically advantageous to provide the layer under the layer with or without an adhesive.

A protective film is laminated on the silicone rubber layer that forms the surface of the waterless lithographic printing plate for direct printing, which has been layered as explained above, in order to prevent the occurrence of scratches, adhesion of chips, etc. You can also do it.

Useful protective films include polyethylene, polypropylene, polystyrene, and polyvinyl chloride.

Examples include films made of polyvinyl alcohol, polyethylene terephthalate, and the like.

The waterless lithographic printing plate for direct printing is based on the present invention.

For example, it is manufactured as follows. First, dioxane,
Naphthoquinone-1,2- dissolved in a solvent such as tetrahydrofuran or ethylene glycol monoethyl ether
To novolac resins esterified with diazide-5 or 4-sulfonic acid.

A predetermined amount of fine powder with a predetermined particle size distribution is added.

It is dispersed using a paint conditioner, ball mill, triple roll, etc., passed through a desired filter as necessary, and coated on a support layer having rubber elasticity using a normal reverse roll coater, air knife coater, Meyer bar coater, etc. The photosensitive resin layer is obtained by coating and drying using a rotary coating device such as a coater or a wheller. Next, an adhesive layer is applied on this photosensitive resin layer in the same manner as necessary, and after drying, a silicone rubber composition liquid is applied.
Heat at a temperature of 140°C to fully cure.

Form a silicone rubber layer. If you need more.

A protective film is laminated on this silicone rubber layer using a laminator or the like.

The thus produced waterless lithographic printing plate for direct printing of the present invention is exposed to ultraviolet rays after being vacuum-adhered to, for example, a negative film having a predetermined pattern. As a light source that generates ultraviolet rays, a mercury lamp, a carbon arc lamp, a xenon lamp, a metal halide lamp, a fluorescent lamp, etc. can be used. Next, the plate surface is coated with a developing cloth containing developer and a brush.

By rubbing with a sponge or the like, at least the silicone rubber layer in the exposed area is removed, and a printing plate is obtained in which the exposed surface of the photosensitive resin layer or the support layer having rubber elasticity becomes the ink receiving area.

The developer used in the present invention is preferably a mixture of polar solvents such as alcohols such as methanol and ethanol, aliphatic hydrocarbons such as hexane and heptane, and aromatic hydrocarbons such as toluene and xylene. used. Water may be added to the developer for the purpose of increasing safety against fire.

[Example] The present invention will be explained in detail with reference to Examples below.
The embodiments of the present invention are not limited to this.

Example 1 100 parts by weight of a phenol novolac resin 45% (measured by IR spectrum) esterified with nano-1-quinone-1,2-diazide-5-sulfonic acid, and fine particles with an average particle size of 0.9μ or more than 70μ is 0.8% by volume
Calcium carbonate (manufactured by Nitto Funka, NS#2500>10
Dissolve and disperse the 0-fold portion in dioxane using a paint conditioner so that the total solid content is 15-4%.
0.25m1T with Shore A hardness of 70 on top of a polyethylene terephthalate film with a thickness of 0.25rom.
Coated with a #10 Meyer bar coater on a sheet laminated with l-thick butadiene/acrylonitrile rubber.
It was dried at 100° C. for 2 minutes to form a 2.2 μm photosensitive resin layer. On top of this, a 25x4% "Isopar" E solution of a silicone gum composition having the following composition was applied using a #16 Meyer bar coater, and heated and cured at 110°C for 4 minutes to form a 4° 8μ thick silicone gum composition. A silicone rubber layer was obtained.

(a) Polydimethylsiloxane (molecular weight approximately 30,000.

Terminal OH group > 100 parts by weight (b) Vinyltri(methylethylke]-oxime)silane
8 parts by weight (C) 0.1 parts by weight of dibutyltin dilaurate (d>3 parts by weight of γ-aminopropyltriethoxysilane Through the metal halide lamp (manufactured by Iwasaki Electric Co., Ltd.).

6 from a distance of 1TrL using Idle Fin 2000>
After 0 seconds of exposure, the cross section was immersed in a developer solution of ``Isopar'' E/ethanol = 35/65 for 1 minute, and then the pad (
When rubbed with Long Run Carpet (manufactured by Yojima Textile Co., Ltd.), an image faithful to the negative film was obtained with the surface of the butadiene/acrylonitrile rubber exposed.

Next, in order to examine the occurrence of cracks in the planographic plates thus obtained due to repeated impact, compression and shearing forces, tests were conducted using the method described below.

That is, a printing suitability tester (manufactured by Miyakoshi Kikai Co., Ltd.).

M-3 type) was adjusted with an aluminum plate so that a printing pressure of 0.24 m was applied, and on top of that, a width of 10 mm was adjusted so that impact force, compressive force, and shear force were forcibly applied to the test plate. , Two 200 m long cellophane tapes with a thickness of 0.20 mm were pasted parallel to the printing direction at 100 mm intervals and rotated for 5 minutes at a rotation speed of 70 times/min. Magnified 30 times using a microscope. Then, the number of cracks crossing 50 mm of the longitudinal center line of the two cellophane tapes was read, and the number of cracks occurring per 10 mm was defined as the number of cracks.

As a result of the test using this method, the number of cracks in the test plate was always 0.

Comparative Example 1 A waterless lithographic printing plate for direct printing having the same composition as in Example 1 except for the calcium carbonate fine particles was tested in the same manner, and the number of cracks was 88.
Met.

Example 2 Butadiene-acrylonitrile rubber of 0.25n+m with Shore A hardness of 73 (manufactured by Nippon Zeon Co., Ltd., Nirapol 1072) on aluminum with a thickness of 0.24mm
25 parts R1, isobutylated melamine resin (manufactured by Dainippon Ink Co., Ltd., Super Beckamine, L-12l-60)
Example 1 was applied on a substrate provided with a coating layer consisting of 75%
Calcium carbonate (manufactured by Nitto Funka Co., Ltd.) contains fine particles with an average particle diameter of 1.7 μm and 11°1% by volume of fine particles with a diameter of 7.0 μm or more.

A waterless lithographic printing plate for direct printing was obtained which had the same structure except that it was changed to P-LITE #500). When this printing plate was tested in the same manner, the number of cracks was O.

Example 3 The fine particles of Example 2 were made of titanium oxide (manufactured by 6 Hara Sangyo Co., Ltd.) containing 1.5% by volume of fine particles with an average particle size of 0.3μ and 1°0μ or more (excluding fine particles with a size of 7.0μ or more). , Tybake C
A waterless lithographic printing plate for direct printing was obtained which had the same structure except that it was changed to R-58>. This printing plate was tested in the same manner.

The number of cracks was O.

Example 4 The fine particles of Example 2 were mixed into an epoxy resin (manufactured by Toshishiku Co., Ltd.) containing 10.7% by volume of fine particles with an average particle diameter of 1.8 μm and 6°0 μm or more.
A waterless lithographic printing plate for direct printing was obtained which had the same structure except that it had the same structure.

When this printing plate was tested in the same manner, the number of cracks was O.

Comparative Example 2 A waterless lithographic printing plate for direct printing, which had the same photosensitive resin composition as Example 2 except for the fine particles, was tested in the same manner, and the number of cracks was 102.

Claims (1)

[Claims] In a waterless lithographic printing plate for direct printing, in which a photosensitive resin layer and a silicone rubber layer are coated in this order on a support layer having rubber elasticity, the photosensitive resin layer contains (a) 100 parts by weight of a quinonediazide compound. , (b) fine particles having an average particle diameter equal to or less than the thickness of the photosensitive resin layer and exceeding the total thickness of the photosensitive resin layer and the silicone rubber layer are 2.
10 to 150 fine particles with a particle size distribution of 0% by volume or less
A waterless lithographic printing plate for direct printing, characterized in that it contains parts by weight.