JPS59162551A - Treatment of lithographic plate requiring no damping water - Google Patents

Abstract

PURPOSE:To enhance developing speed and to obtain a superior image by treating a lithographic plate requiring no dampening water made of o-naphthoquinone-1,2- sulfonate or the like of a novolak resin, with a soln. contg. a specified alcohol before exposure. CONSTITUTION:A photosensitive layer made of naphthoquinone-1,2-diazide-5- sulfonate or 4-sulfonate of a novolak resin having 35-65% esterification rate is formed on a support of a chemically treated aluminum plate or the like. Said layer is coated with a silicone rubber layer to form a lithographic plate requiring no dampening water. Before exposure, this plate is held in the vapor of at least one kind of CnH2n+1OH (n is 1-5) aliphatic alcohol or a mixture of this and water for about 10min. or immersed in that liquid or treated otherwise. After exposure, it is immersed in a developing soln., and developed by rubbing it with a pat. A superior image free from pin-holes, cracks, etc. is obtained in a time shorter than the conventional ones.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for processing a lithographic printing plate that does not require dampening water, and relates to the production and exposure of a lithographic printing plate material that does not require dampening water.

It is used in the developing process.

[Prior art]

In conventional planographic printing using the offset method, the composition of the dampening water, the amount supplied, and the balance with the ink have a large effect on the printing results, so extremely advanced technology is required for supplying the dampening water. For this reason, the offset printing industry has long awaited the emergence of a lithographic printing plate that does not require dampening water.

In recent years, many proposals have been made regarding waterless lithographic printing plates that meet this requirement.

For example, JP-A-55-59466 and JP-A-55-110249 disclose a lithographic printing plate that does not require dampening water and uses a novolac resin naphthoquinone-1,2-diazide-5-sulfonic acid ester as a photosensitive layer. Disclosed.

This printing plate is made by rubbing the surface with a cloth, plan, etc. impregnated with a solvent that penetrates the silicone rubber layer and dissolves the portion that has changed into a carboxylic acid compound in the exposed area, dissolving the photosensitive layer in the exposed area and The developing method involves peeling off the silicone layer. However, the development speed is not sufficient, and there are variations in the speed, and the development speed decreases significantly especially when stored in a dry atmosphere, making it difficult to control the development conditions. .

[Purpose of the invention]

The inventors of the present invention made extensive studies to solve the above-mentioned problems, and as a result, the printing plate was prepared using water and the general formula CoH2n+10H.
(n=positive integer of 1 to 5) When processing with a processing liquid consisting of one or more types selected from the group of aliphatic monohydric alcohols, exposing and developing two images, the development speed becomes faster.
! They discovered that by applying this treatment to a plate that had been stored in a dry atmosphere and whose development speed was significantly reduced, the development speed became uniform and the development speed was dramatically increased.9 This led to the present invention. It was.

[Structure of the invention]

That is, in the present invention, the esterification rate is 65 to 6 on the support.
A photosensitive layer consisting of 5% naphthoquinone-1,2-diazide-5-sulfonic acid ester or 4-sulfonic acid ester of novolac resin and a silicone rubber layer were prepared in this order in a lithographic printing plate that did not require dampening water and was exposed to light. Water and the general formula CnH2n+, 0H (n-1 to 5
The present invention relates to a method for processing a lithographic printing plate that does not require dampening water, characterized in that it is processed with a processing liquid consisting of one or more selected from the group of aliphatic monohydric alcohols (positive integers).

The reason why the processing method of the present invention increases the development speed of egg white has not yet been fully elucidated, but it is thought that it can be explained as follows.

In other words, the development speed of conventional printing plates with a photosensitive layer made of orthonaphthoquinone diazide sulfonic acid ester of novolak resin is not sufficient, and the reason why the speed fluctuates is that ketene compounds produced by exposure to light are present in the photosensitive layer. Not only does it react with moisture to produce a carboxylic acid compound, but it also reacts with the residual hydroxyl groups derived from the novolac resin, resulting in some cross-linking due to ester bonds, which may slow down the development speed.
Become.

Moreover, it is thought that the production rate of carboxylic acid compounds and ester bonds varies depending on the moisture content present in the photosensitive layer at the time of exposure, resulting in variations in development speed. Of course,
When stored in a dry atmosphere.

Needless to say, the production rate of ester bonds increases and the development speed becomes extremely slow.

On the other hand, in the printing plate subjected to the processing method of the present invention, water or C1-5 aliphatic monohydric alcohol, which can easily react with the ketene compound generated by exposure, diffuses into the photosensitive layer. Since it is impregnated and sufficiently present, it does not react with the hydroxyl group derived from the novolac resin to form an ester bond and cause crosslinking, so it is thought that the solubility in the developing solvent such as alcohol does not decrease.
.

Book below. The configuration of the invention will be described in detail.

The photosensitive layer is a novolac resin obtained by condensing phenol or cresol with formaldehyde, naphthoquinone-1,2-diazide-5-sulfonic acid ester, and 4-sulfonic acid ester with an esterification rate of 35 to 65.
% (measured from IR spectrum) is used. When the esterification rate is less than 35%, a difference appears in the solubility of the exposed and unexposed areas in the developing solvent.
If it exceeds 65%, it is economically disadvantageous. The thickness of the photosensitive layer is preferably 05 to 5 microns. If it is too thin, it will cause pinholes, and if it is too thick, cracks will easily occur, and it will also be disadvantageous from an economic standpoint.

Necessary additives such as pigments, dyes, resins, plasticizers, etc. can be added to the photosensitive layer as long as they do not impair its performance.

The thickness of the silicone rubber layer used as the ink repellent layer used in the present invention is 05 to 100 μm.

Preferably, those having a diameter of 1 to 50 μm are used. A useful silicone rubber 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.

(R is an alkyl group having 1 to 10 carbon atoms or a phenyl group, and preferably 60% or more of R is a methyl group.) This linear organic polysiloxane is usually one having two terminal hydroxyl groups. It is cross-linked by heat treatment in the presence of a cross-linking agent such as , acetoquinsilane, ketoxime 7-lane, or alkoxysilane in the presence of a catalyst such as an organic tin compound, and used as a silicone rubber layer.

If necessary, a known silicone primer or a silicone coupling agent layer may be provided between each layer for adhesion between the silicone rubber layer and the photosensitive layer or between the photosensitive layer and the support, or a known silicone primer or silicone coupling agent layer may be provided between the silicone rubber layer or the photosensitive layer. It is also effective to add a silicone primer or plan coupling agent.

As the support, paper, plastic film or sheet, natural or synthetic rubber sheet, metal plate, etc. are used. These supports can be further provided with a coating layer or a laminating layer for prevention of nolation and other purposes.

The silicone rubber layer forming the surface of the dampening water-less lithographic printing plate constructed as described above is intended to prevent the occurrence of scratches and the adhesion of flakes.

A protective film can also be laminated. Useful protective films include polyethylene, polypropylene, polyvinyl chloride, and vinyl alcohol.

Examples include polyethylene terephthalate.

The lithographic printing plate that does not require dampening water according to the present invention is manufactured, for example, as follows. First, on the support, reverse roll coater and air knife coater.

A photosensitive material solution is applied using a normal coater such as a Meyer bar coater or a rotary coating device such as a Whaler, and after drying, an adhesive layer is applied as needed on top of this photosensitive layer using the same method and dried. 9 Then, a silicone rubber solution is applied in the same manner and heat treated at a temperature of usually 100 to 120° C. for several minutes to fully cure and form a silicone rubber layer. Furthermore, if necessary, a protective film is laminated on this silicone rubber layer using a laminator or the like.

The dampening water-less lithographic printing plate thus produced is processed by the method of the present invention twice, exposed to light for two images, and then developed.

As a treatment liquid, water and general formula C1H2n+10H(n
= positive integer from 1 to 5) A mixture of one or more selected from the group of aliphatic monohydric alcohols is used. n
If it exceeds 5, penetration into the photosensitive layer may be slow (unsuitable for the present invention). Specific examples of aliphatic monohydric alcohols include methanol, ethanol, n-furopanol, imprononol, n-butanol, infrinol, see.
-phthanol.

tert. -butanol, n-pentanol, impentanol, 2-pentanol 3-pentanol te
rt. -Pentanol and the like. These can be used alone or in combination of two or more, and can also be used in combination with water.

The mixing ratio of these can be arbitrarily selected depending on the desired processing speed, the composition and thickness of the photosensitive layer and silicone rubber layer, the material and thickness of the cover film when processing is performed with the cover film attached, etc. It is not something that can be determined uniquely. Furthermore, the solution does not necessarily have to be a uniform mixed solution.

Although various methods can be used for processing with these processing liquids, the methods described below are typical.

The first method is to immerse the printing plate in a bath filled with these processing solutions with or without stirring. The second method is a method in which a cloth or paper impregnated with a processing liquid is brought into close contact with the silicone rubber layer side of the printing plate. The sixth method is to expose to the vapor of the processing liquid, for example, by filling a sealed tank with the vapor of the processing liquid.
This is a method in which the printing plate is placed in it and impregnated. In the impregnation process, it is preferable to heat the processing liquid in order to make the diffusion into the photosensitive layer more rapid. It is preferable that the heating temperature does not exceed 120° C. in order to prevent thermal decomposition of the photosensitive layer. Also,
A surfactant, a swelling agent for the silicone rubber layer, etc. may be added to the processing solution to aid diffusion. These treatments may be performed immediately before exposure, or after the treatment may be stored in an airtight container to prevent evaporation of the processing solution.

The dampening water-free lithographic printing plate of the present invention manufactured and processed as described above is exposed to ultraviolet rays by vacuum-adhering a negative film having a predetermined number of turns, for example. 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, when the surface is rubbed with a developing pad such as a cloth or brush impregnated with a developer, the photosensitive layer in the exposed area is dissolved, and the upper silicone rubber layer is easily peeled off to expose the support.

As a developer, it penetrates the silicone rubber layer.

A material that dissolves or swells only the exposed photosensitive layer is used. Such developing solutions include methanol,
Alcohols such as ethanol are preferred because they allow easier penetration into the photosensitive layer.

It is also preferable to use a mixture of aliphatic hydrocarbons such as hexane and heptane, and aromatic hydrocarbons such as toluene and kiln, which can swell the silicone layer.

The present invention will be explained in more detail below with reference to Examples.
The embodiments of the present invention are not limited thereto.

Example 1 Ester (f[
53% phenolic novolac resin (manufactured by Tensei Durez:
naphthoquinone-1 of Sumiresin P'R~50235),
A 200% by weight ethyl cellosolve solution of 2-diazide-5-sulfonic acid ester was applied using a +-10 bar coater and dried at 100°C for 65 minutes to form a 25μ photosensitive layer. On top of this, 2% by weight of γ-aminopropyltriethoxysilane (manufactured by UOC: A-1100) / Isopar E (manufactured by Esso) / isopropanol = 80 /
2 D (Gravity jft ratio) Set film thickness after drying the solution 0.0
After coating with a bar coater as 8μ, 120℃, 40℃
Dry for seconds.

After applying a 25 thiaisopar E solution of a silicone composition having the following composition on this with a #=16 bar coater, 12
It was cured by heating at 0° C. for 35 minutes. The thickness of the silicone rubber obtained at this time was 46μ.

(a) 100 parts i of polydimethylsoloxane (
Molecular weight approximately 80,000, terminal OH group) (b) Ethyltriacetoxysilane 5-fold H part (
C) Dibutyltin acetate 02 parts by weight The printing original plate obtained as described above was immersed in boiling water for 10 minutes, and then passed through a vacuum-adhesive negative film having a linear image with a line width of 100μ to 15mm using a metal halide lamp (Iwasaki Electric). Exposure was carried out for 60 seconds from a distance of 1 m using a Nidorfin 2000 (manufactured by Nippon Steel & Co., Ltd.). After the plate surface was immersed in the ethanol developer for 1 minute, it was rubbed with a pad (Long Run Carpet, manufactured by Yojima Textile) under a load of 10 g/an2, and the silicone layer in the exposed area was removed by rubbing 12 times. An image that is faithful to Lee Gafilm, in which the surface of chemically treated aluminum is exposed, was obtained.

Example 2 The original printing plate obtained in Example 1 was brought into contact with ethanol-impregnated gauze from the silicone rubber layer side, sealed in a polyethylene bag, and submerged in a 60°C water bath for 6 minutes.
After exposure and development.

It took 10 scrapings to expose the surface of the chemical conversion treated aluminum in the exposed area.

Comparative example 1 The original printing plate obtained in Example 1 was left untreated.

When exposed and developed in the same manner, it took 94 rubbings until the surface of the chemically treated aluminum in the exposed area was exposed.

Example 6 Polyethylene terephthalate with a thickness of 0.25 mm was used as a support, and naphthoquinone-1,2-diazide-5-sulfonic acid of phenol novolac resin (manufactured by Sumitomo Durez: pR-5073j) with an esterification rate of 48% was applied thereon. After spin-coating a 7% by weight solution of ester in dioxane with a wheal,
It was dried at 100° C. for 35 minutes to form a 25 μm photosensitive layer. On top of this, γ-aminopropyltriethoxysilane (
Manufactured by UcC: A-1100) 05 Weight Section Ain Par E
(manufactured by Esso) After drying, the solution was dried to a set thickness of 0.04μ, and after spin-coating with a wheal, it was dried at 120°C for 60 seconds.

On top of this, a 7thiaisopar E solution of a silicone composition having the same composition as in Example 1 was spin-coated with Poera, and then heated at 120°C and 65°C.
Cured by heating for minutes. The thickness of the obtained silicone rubber layer was 23μ.

After holding the printing original plate thus obtained in a tank filled with 100 tons of water vapor for 10 minutes.

Exposure and development, Isopar E/ethanol = 8 as liquid
When development was carried out in the same manner as in Example 1 using 0/20, 8 rubbings and 9 rubbings were required until the surface of the polyethylene terephthalate in the exposed area was exposed.

Example 4 The printing original plate obtained in Example 6 was stored for 12 hours in a closed container at 20° C. that had reached the saturated vapor pressure of Improper Tool, and then exposed and developed in the same manner as in Example 6 (!). Six rubbings were required until the surface of the polyethylene terephthalate in the exposed area was exposed.

Comparative example 2 The original printing plate obtained in execution 913 was left untreated.

When exposed and developed in the same way, it took 58 times of rubbing until the surface of the polyethylene terephthalate in the exposed area was exposed.
The number of times was necessary.

Example 5 Only the silicone rubber layer was added to a 25% by weight Einpar E solution having the same composition as the silicone rubber composition used in Example 1.
4% by weight of γ-aminepropyltriethoxysilane (manufactured by UOCj: A-1100) based on the silicone rubber composition.
) was added, but otherwise a printing original plate was obtained under the same conditions, and after being immersed in a tank filled with 820 parts by weight of Isopar and 80 parts by weight of ethanol at 20°C for 30 minutes, the same process as in Example 6 was carried out. When exposed and developed, the surface of the chemical conversion treated aluminum in the exposed area was exposed after 10 rubbings.

Comparative example 6 The original printing plate obtained in Example 5 was left untreated.

When exposed and developed in the same manner, it took 9 times of rubbing 68 times until the surface of the chemical conversion treated aluminum in the exposed area was exposed.

Patent applicant Higashi Shikushiki Kaisha 41

Claims (1)

[Claims] A photosensitive layer consisting of naphthoquinone-1,2-diazide-5-sulfonic acid ester or 4-sulfonic acid ester of a novolak resin with an esterification rate of 65 to 65% on a support;
In a planographic printing plate that does not require dampening water and is formed by coating a silicone rubber layer in this order, the printing plate before exposure is coated with water and a fat of the general formula C9H,,n+,OH (n=positive integer from 1 to 5). A method for processing a lithographic printing plate that does not require dampening water, characterized by processing with a processing liquid consisting of one or more types selected from the group of monohydric alcohols.