JPS58163944A - Manufacture of lithographic original plate requiring no dampening water - Google Patents

Abstract

PURPOSE:To enhance the original image reproducing power of a lithographic original plate requiring no dampening water and the adhesive strength of the plate to an original image by applying a soln. of a polymer nondispersible in water to the uppermost layer of the plate and by drying it to form an uneven coating. CONSTITUTION:A photosensitive layer which is photoset or photosolubilized by irradiating active light is formed on a substrate such as a plastic film or an Al plate, and a silicone rubber layer is formed on the photosensitive layer. A soln. of a polymer nondispersible in water is applied to the uppermost layer by means of a wheeler or the like and dried to form an uneven coating having about 0.1-200mum thickness. Thus, the desired lithographic original plate requiring no dampening water is obtd. The polymer soln. is prepared by graft- polymerizing >=2 kinds of vinyl monomers such as acrylic acid and 2-hydroxyethyl methacrylate in an org. dispersion medium such as hexane or toluene.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a lithographic printing original plate that does not require dampening water, and in particular has excellent reproducibility of the original image and adhesion to the original image (positive or negative film) and does not require dampening water. The present invention relates to a method for producing a lithographic printing original plate.

A planographic material having a silicone rubber layer as the top layer and requiring no dampening water is disclosed in 9, for example, Japanese Patent Publication No. 44-23042. Special Public Service 1977-160
No. 44, JP 51-17081, JP 48-94
Many proposals have been made in issues such as 5o5.

In addition, lithographic materials that do not require dampening water and have a silicone rubber layer under a photosensitive image forming layer (hereinafter referred to as photosensitive layer) are disclosed in 9, for example, Japanese Patent Publication No. 44-25042, Japanese Patent Publication No. 471-2361, and Japanese Patent Application Laid-Open No. 1987-49- No. 82402, Japanese Unexamined Patent Publication No. 1973-
No. 16155, Japanese Patent Application Laid-Open No. 55-849!19, etc.

Furthermore, a lithographic plate material that does not require dampening water and in which the silicone rubber layer itself retains photosensitivity has been proposed.

In order to form images on these lithographic materials that do not require dampening water, exposure to active light is usually performed through the original image.
To faithfully reproduce the original painting.

It was necessary to bring the original picture into complete contact with the upper surface of the planographic plate. For this reason, the general method is to place the lithographic material and the original image between the rubber sheet and the pressure-bonded glass, and create a vacuum between the rubber sheet and the pressure-bonded glass to bring them into close contact (hereinafter referred to as the vacuum adhesion method). has been used.

However, the surface of conventional planographic materials that do not require dampening water and has a silicone rubber layer as the top layer is very smooth, and the silicone rubber has very good adhesion, so once the original film and silicone rubber layer are in close contact with each other, As a result, the adhesion area becomes firmly fixed, and if air bubbles appear between the original film and the silicone rubber layer, even if air is sucked from the periphery of the planographic material using the vacuum adhesion method, It is difficult to remove the trapped air bubbles. Therefore, in order to completely adhere the original image to the entire surface of the planographic material, especially when the plate size is large,
A very long time was required, and in extreme cases, no matter how much time was spent, the film would not adhere properly.

Further, even in the case of planographic materials that do not require dampening water and have a silicone rubber layer under the photosensitive layer, similar problems occur to a lesser extent.

The fact that vacuum adhesion takes a long time not only reduces the efficiency of the plate-making process and is extremely uneconomical, but also makes it difficult to faithfully reproduce the original image if exposure is performed without sufficient adhesion to the original image. The fatal problem was that it could not be reproduced.

In order to solve this problem, it has been proposed to laminate a plastic film made of polyester, polyolefin, or the like on one plate surface. However, when a plastic film is laminated on the plate surface, the vacuum adhesion with the original image improves slightly, but it is insufficient.Furthermore, when the plastic film is placed on the plate surface, there may be foreign matter or air between the silicone rubber layer or the photosensitive layer. There were problems such as technical difficulties such as easy pinching and economical disadvantages.

Furthermore, a plastic film is placed on the plate surface.

The distance between the original image and the photosensitive layer increases during exposure, and current exposure machines that do not provide ideal parallel light rays tend to cause so-called blurring, making it difficult to reproduce images that are faithful to the original image.

In addition, when using a type of photosensitive layer that decomposes upon exposure and releases nitrogen gas, the gas generated during exposure accumulates between the original image and the printing plate, pushing the original image upward, resulting in poor adhesion of the original image. , causing burnout.

Similarly, if a silicone rubber layer or a plastic film is provided on the photosensitive layer, the gas generated by exposure will push up the plastic film, increasing the distance from the original image and causing fading. I have a similar problem.

In order to improve such problems, for example, by spraying a solution or dispersion containing a non-volatile component onto the surface of the silicone rubber layer of a lithographic printing original plate that does not require dampening water and has a silicone rubber layer as the uppermost layer, A lithographic printing original plate that does not require dampening water and has a silicone rubber layer with unevenness has been proposed (Japanese Patent Laid-Open No. 56-27150). The lithographic printing original plate proposed here that does not require dampening water can be expected to be quite effective in terms of vacuum adhesion to the original image, but it requires skill to form, for example, uniform irregularities on the surface of the silicone rubber layer. In some cases, on the surface of the silicone rubber layer where no unevenness is formed,
There were problems such as damage to the silicone rubber layer, and further improvements were desired.

The inventors of the present invention have conducted extensive studies on a lithographic printing original plate that does not require dampening water and has excellent quality that solves the above problems, and as a result of these studies, they have arrived at the present invention described below.

That is, in the present invention, a non-aqueous dispersion polymer solution is applied to the top layer of a lithographic printing original plate that does not require dampening water, and then dried.

5- This relates to a method for producing a lithographic printing original plate that does not require dampening water and is characterized by providing a coating layer having irregularities.

The non-aqueous dispersion polymer solution applied to the top layer of the lithographic printing original plate that does not require dampening water of the present invention does not have any physical or chemical adverse effects on the components that make up the plate material, and easily prevents stains during development. Any material that can be removed and does not react with the developer used can be used.

The non-aqueous dispersion polymer solution used in the present invention is composed of a polymer obtained from a 9-order vinyl monomer and an organic dispersion medium. Further, it is also possible to add a dispersion stabilizer and the like to the polymer solution as necessary.

Examples of monomers that provide polymers useful in the present invention include acrylic acid and n-butyl acrylate.

(meth)ethyl acrylate, methyl (meth)acrylate, isobutyl methacrylate, lauryl methacrylate, cyclohexyl methacrylate, 2-hydroxyethyl methacrylate, 2-6-ethylhexyl methacrylate, γ-methacryloxypropyltrimethoxysilane, Examples include styrene. Two or more of these monomers are used as a graft-polymerized polymer.

Among these, a combination of polymers in which one is a dispersion polymer and the other is a soluble polymer is particularly effective in the present invention.

The organic dispersion medium used in the present invention varies depending on the type of polymer used, but examples include the following.

(1) Aliphatic hydrocarbons hexane, cyclohexane, methylcyclohexane,
Isopar E'' (Esso Chemical product) etc.

(2) Aromatic hydrocarbons benzene, toluene, xylene nat.

(3) Other ethyl acetate, butyl acetate, cellosolve acetate, tetrahydrofuran, methanol, propatool, ethanol, phthanol, ethyl calpitol, butyl calpitol, ethyl cellosolve.

butyl cellosolve etc.

These organic dispersion media can be used not only alone, but also as a mixture of two or more.

A known method is used to produce the non-aqueous dispersion polymer solution used in the present invention.

The non-aqueous dispersion polymer solution prepared in this way is applied to the top layer of the lithographic printing original plate that does not require dampening water and is dried, thereby forming a coating layer with irregularities on the lithographic printing original plate that does not require dampening water. It is formed.

For coating, various coating devices such as a wheller, bar coater, slit die coater, etc. are not specified, but any coating device can be used as long as it does not impair the performance of other plate materials. For example, if the temperature is 20°C, it may be for as long as economically possible, and if the temperature is 150°C, it may be for 5 to 10 seconds.
1 In this way, a coating layer with unevenness is formed, and the thickness of this coating layer is in the range of 0.01 to 200 μm, more preferably 0.01 μm to 200 μm.
A range of 1 to 50μ is selected. If the coating layer is too thin, problems will arise in terms of adhesion to the original image and protection of the printing plate.

On the other hand, if it is too thick, problems may arise in terms of reproducibility of the original image.

The surface of the uneven coating layer of the present invention is slightly roughened. That is, the surface roughness is H8L as specified in J.
A (center line surface roughness) is 0.05 to 100μ.

Preferably it is in the range of 01 to 20μ.

HOI, A" As the value becomes smaller than 05μ, the effect of shortening the vacuum adhesion time disappears. On the other hand, when it becomes larger than 100μ, the distance between the original film and the planographic material becomes too large, causing blurring and other problems, resulting in insufficient image reproducibility. is not obtained.

The minute roughening referred to here means 9, for example, irregularities on the surface of the coating layer.
That is, the average distance from adjacent convex parts is 0.
As the average distance becomes shorter than about 05μ, the effect of shortening the vacuum adhesion time decreases, and conversely, as the distance becomes longer than about 9-2000μ, the distance between the original film and the planographic material decreases. Adhesion tends to be insufficient, and sufficient images cannot be reproduced.

Furthermore, the shape of the unevenness of the present invention is not particularly limited, and may have different shapes depending on, for example, the composition of the coating liquid or the coating method.

The shape and surface roughness may all be the same or may be a mixture of various shapes.

The lithographic printing original plate that does not require dampening water to which the method of the present invention is applied is:
It may have a photosensitive silicone rubber layer lined to the substrate, or it may have a known photosensitive layer lined to the substrate via an adhesive layer if necessary under the silicone rubber layer. It's okay. Further, a silicone rubber layer may be provided below the photosensitive layer and backed to the substrate via an adhesive layer, if necessary.

It is also applicable to a planographic printing original plate having such a structure with a plastic film provided thereon.

The substrate, photosensitive silicone rubber layer, photosensitive layer, and silicone rubber layer constituting the above-mentioned dampening water-less lithographic printing plate will be described below.

Suitable substrates include paper, plastic films or sheets, metal plates, etc. with a thickness of about 10 .mu.m to 2 mm, preferably about 50 .mu.m to 500 .mu.m.

A substrate having rubber elasticity or a cylindrical substrate may also be used.

The photosensitive silicone rubber layer itself is photosensitive, and in this case, no photosensitive layer is required. As the photosensitive silicone rubber, γ-methacryloxyprobyltrimethoxy and silane are added to the terminal OH group of dimethylpolysiloxane.

Alternatively, examples include compounds obtained by dealcoholing condensation of monocinnamoyljethoxysilane, compounds obtained by adding a bisazide compound to polydiorganosiloxane, or compounds obtained by reacting acryloyl chloride or p-azidobenzoate.

It is also possible to use a photosensitive silicone rubber layer prepared by mixing silicone rubber with a known photosensitive substance.

The photosensitive layer is a layer that has the property of being photocured or pre-solubilized by irradiation with active light. Although its thickness is arbitrary, it is preferably about 100 microns or less, more preferably about 0.5 to 10 microns.

As the photosensitive material, one having the following first-order structure is suitable.

(1) An unsaturated monomer or oligomer thereof with a boiling point of 100°C or higher and non-volatile at room temperature, a photosensitizer, a thermal polymerization inhibitor, and if necessary, a filler to provide shape retention at room temperature and Composition containing some additives.

As an unsaturated monomer, ethylene glycol di(meth)
Acrylate, polyethylene glycol di(meth)acrylate, hydroxyethyl(meth)acrylate, hydroxypropyl(meth)acrylate, glycidyl(
A series of acrylic esters such as meth)acrylate, 1-chloro-2-hydroxyethyl(meth)acrylate, dimethylamine ethyl(meth)acrylate, methacrylic esters, ethylenebisacrylamide, N-methylolacrylamide, methoxymethyl Acrylamide derivatives such as acrylamide, allyl alcohol noesters such as triallyl cyanurate, triallyl phosphate, diallyl phthalate, diallyl maleate, other styrene/derivatives, cinnamic acid derivatives, etc. can be used.

Benzophenone derivatives are used as photosensitizers.

Benzoin derivatives, anthraquinone derivatives, aldehydes, ketones, sulfur compounds, /%rogen compounds, or dyes such as methylene blue and riboflavin can be used.

Hydroquinone derivatives are used as thermal polymerization inhibitors.

Phenol derivatives, nitro-substituted benzenes, quaternary amines, and phenothiazine derivatives are used.

Fillers or additives include colloidal silica, calcium carbonate, and magnesium carbonate.

Fine powders of inorganic substances such as iron oxide, polyvinyl acetate, poly(meth)acrylic acid esters, vinyl polymers such as polyethylene, polypropylene, polyvinyl chloride, polyvinylidene chloride, etc. with a molecular weight of several thousand, resole phenolics before curing , urea-based, melamine-based, epoxy-based, unsaturated polyester-based resins, etc.

(2) Photocurable diazo resin or azide resin and if necessary a photosensitizer and some filler additives.

Examples of photocurable diazo resins include paradiazophenylamine and paradiazomonoetheraniline.

Examples include zinc chloride double salts of condensates of diazo amines such as paradiazobenzylethylaniline and formaldehyde.

Examples of the photocurable azide resin include azidophthalic ester of polyvinyl alcohol, azidobenzoic ester, styrene-maleic anhydride copolymer, and aromatic azido alcohol.

Examples include ester of β-(4-azidophenol)ethanol.

As the photosensitizer, filler, and additives, those listed in the example (1) can be used.

14- (3) A photosensitive material that combines orthoquinone diazides and novolak resin.

In the present invention, a more preferred photosensitive material is a photosensitive material that combines orthoquinone diazides and novolak resin.

The silicone rubber layer used in the present invention usually has a
100μ, preferably about 0.5 to 30μ thick and 0
The main component is a linear organic polysiloxane with a molecular weight of several thousand to several tens of blades and having the following repeating units.

Here, 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. Such a linear organic polysiloxane can be sparsely crosslinked to form a silicone rubber by adding an organic peroxide and subjecting it to heat treatment.

A crosslinking agent is also added to the silicone rubber layer. Crosslinking agents used in so-called room temperature (low temperature) curing silicone rubber include acetoxysilane, ketoxime silane, alkoxysilane, aminosilane, and amidosilane.

These are usually linear organic polysiloxanes that end in hydroxyl groups, and are of the acetate-free type, oxime-free type, alcohol-dealing type, and amine-philic type, respectively. It becomes a deamidated silicone rubber. Generally, a small amount of an organic tin compound or the like is further added as a catalyst to these silicone rubbers.

If necessary, an anchor coat layer may be provided between the substrate and the photosensitive layer or silicone rubber layer to improve the adhesion between the photosensitive layer or silicone rubber layer and the substrate, or to prevent halation. It is also useful to provide an adhesive layer to improve adhesion to the rubber layer.

U, t-
AK Hyr After exposure, the silicone rubber layer in the image area is developed and removed together with the underlying photosensitive layer, or only the silicone rubber layer is removed. If necessary, a known photosensitive layer may be provided on the silicone rubber layer with an adhesive layer interposed therebetween, and after exposure, the photosensitive layer in non-image areas may be removed by development.

By using the lithographic printing original plate that does not require dampening water of the present invention,
The adhesion to the original image is improved and the time required for adhesion can be significantly shortened. Furthermore, it has become possible to faithfully reproduce images.

Further, the coating layer provided on the silicone rubber layer or the photosensitive layer can be removed very easily during development after exposure to one image, and does not adversely affect the forming performance during printing.

Furthermore, the coating layer provided on the silicone rubber layer or photosensitive layer is a continuous coating layer formed by applying and drying a solution, and has the effect of protecting the easily damaged silicone rubber layer or photosensitive layer. When applied to a plate material that not only has a It can also be expected to have the effect of preventing poor vacuum adhesion caused by this.

Hereinafter, the present invention will be explained in more detail with reference to Examples.

Example 1. Comparative example 1 Chemically treated aluminum plate manufactured by Sumitomo Light Metal ■ (thickness 3o).

A photosensitive layer having the following composition was coated on the substrate (μ) to a dry thickness of about 1.2μ.

(a) Naphthoquinone-1 of phenol novolac resin (Sumitomo Bakelite: Sumiresin PR50235)
, 2-diazide-5-sulfonic acid ester (degree of esterification: 44 degrees).

(a) 100 parts by weight of 5H-78119 manufactured by Toray Silicone (b) 4 parts by weight of γ-aminopropyltriethoxysilane This plate was cut into a size of 50 (2) x 50 cm.

Non-aqueous dispersion polymer solution A was applied onto the silicone rubber layer of this plate.
After diluting the solid content to 100 parts by weight with "Isopar E" (an aliphatic hydrocarbon solvent manufactured by 0 Tsuso Kagaku ■), it was coated with a wheal and dried at 100°C for 60 seconds to give a thickness of 66 μm and an average unevenness of 05 μm ( A coating layer of H (indicated by IA) was formed.

Next, an original image (negative film) having a halftone dot area ratio of 50 cm was layered on the lithographic printing original plate that did not require dampening water, and the original image (negative film) having a dot area ratio of 50 cm was superimposed on the original plate created in this manner and the vacuum was adhered using the usual method, and the adhesion was complete in 30 seconds. . Next is exposure.

When developed, good halftone dots were reproduced. Further, the coating layer on the silicone rubber layer was completely removed during development.

On the other hand, for comparison, when a dampened horizontal plate printing original plate without a coating layer on the silicone rubber layer was used and the original image was vacuum-adhered in the same manner as above, air bubbles were generated between the original image and the silicone rubber layer over the entire surface of the 9th plate. Even after continued suction for 20 minutes, the bubbles did not disappear. Next, expose in this state.

When developed with ethanol, the halftone dots reproduced in areas where air bubbles were generated and did not adhere well to the original image were not in good shape due to blurring.

In addition, the non-aqueous dispersion polymer solution A was created as follows.

50 g of lauryl methacrylate is reacted in 100 g of "Isopar E" (aliphatic hydrocarbon solvent manufactured by Esso Kagaku ■) at 80'C for 6 hours using 1 g of benzoyl peroxide as a polymerization initiator. Next, approximately 1 g of styrene and 1 g of benzoyl peroxide were added to the reaction solution obtained here.
By dropping it over time and then reacting at 80°C for 6 hours.

A milky white non-aqueous dispersion polymer solution was prepared.

Example 2. Comparative Example 2 A 0.25 m thick film was placed on a 0.3 mm thick aluminum plate.
m, c) Yor A Rubber A 10% solids solution (solvent: ethanol) having the following composition was applied onto a substrate provided with a nitrile rubber layer with a hardness of 70, and dried in 80°0 hot air to a thickness of 6 μm. A photosensitive layer was provided.

(a) 50 parts by weight of a 5o15o/2o copolymer of methyl methacrylate/methyl acrylate/acrylic acid (b) 48 parts by weight of an addition reaction product of 4 moles of glycidyl methacrylate and 1 mole of xylylene diamine (C) Michler's ketone 2 parts by weight 10% by weight of a silicone rubber composition having the following composition on this photosensitive layer:
Apply n-hexane solution, dry in 50°C hot air,
A silicone rubber layer with a thickness of 2 μm was provided.

(a) Polydimethylsiloxane (molecular weight approximately 80,000) 1
00 parts by weight (b) Methyltriacetoxysilane 5 parts by weight (
C) Dibutyltin acetate 0.2 parts by weight
An X 30 rn size was cut out, and the non-aqueous dispersion polymer solution B was placed on the silicone rubber layer of this plate in "Isopar E" (aliphatic carbide 21-hydrogen solvent manufactured by Esso Chemical ■)/toluene. After diluting with a 2:1 (weight ratio) to a solid content concentration of 20%, use a bar coater (≠12)
The coating layer was coated at 100° and dried for 30 seconds to form a coating layer with a thickness of 36 μm and an average unevenness of 1.0 μm (indicated by HOLA).

A positive film having an area ratio of 10% and a halftone dot image of 150 lines was superimposed on the lithographic printing original plate which did not require dampening water and was vacuum-adhered to the film, and the film was completely vacuum-adhered in about 20 seconds. Subsequently, the image was exposed to light and developed by rubbing with a cotton pad soaked with ethanol, resulting in a halftone image faithful to the original image with no burn marks. Further, the provided coating layer was completely removed during development.

On the other hand, for comparison, when we performed the same operation using a lithographic printing original plate that did not require dampening water and did not have a coating layer of non-aqueous dispersible polymer on the silicone rubber layer, suction was continued for 20 minutes during vacuum contact. However, air bubbles formed between the positive film and the silicone rubber layer did not disappear. Subsequent exposure and development revealed that the halftone dots in the areas where the bubbles had occurred had lost their shape due to blurring.

Note that the non-aqueous dispersion polymer solution B was created as follows.

2 og of 2-ethylhexyl methacrylate was added to 100 g of "ISOPAR E" (manufactured by Esso Chemical ■, aliphatic hydrocarbon solvent)/toluene-3/1 (weight ratio) at 90°0, using 1 g of benzoyl peroxide as a polymerization initiator. Allow to react for 6 hours. Next, 70 g of styrene, 10 g of γ-methacryloxypropyltrimethoxysilane, and 1 g of benzoyl peroxide were added dropwise to the reaction solution obtained here over a period of about 1 hour, and the reaction was then carried out at 90° for 0.6 hours to form a milky white product. A non-aqueous dispersion polymer solution was prepared.

Example 6 One coat of Toray silicone silicone primer “sn 4o94 primer” was applied on a brush-polished aluminum plate.
It was applied to a thickness of μ. On top of that, Toshiba silicone g, n
Tv silicone gum dispersion [yg 308
A solution prepared by diluting 5J with n-hebutane and adding 3 parts by weight of benzoin ethyl ether to the solid content was applied and air-dried to form a silicone rubber layer with a thickness of 5 μm.

On the other hand, a 2 μm thick photopolymerizable adhesive layer having the following composition was formed on a 9 μm thick polyethylene terephthalate film “Lumirror” manufactured by Toshi.

(a) 95% by weight of an addition reaction product of 4 moles of glycidyl methacrylate and 1 mole of xylylene diamine (b) 5% by weight of benzoin methyl ether Next, these were added using a calender roller.

The surface of the silicone rubber layer and the surface of the photopolymerizable adhesive layer are pressed together so that they are in close contact with each other, and then the same non-aqueous dispersion polymer solution A used in Example 1 is applied onto the photopolymerizable adhesive layer or the polyethylene terephthalate film. After diluting the solid content with "Isopar E" (an aliphatic hydrocarbon solvent manufactured by Esso Chemical ■) to a solid content of 7 parts by weight, apply it with a Whaler and apply it to 90"
After drying at 0 for 35 seconds, a coating layer having a thickness of 3 μm and an average convexity of 05 μm (Hol, indicated by A) was provided on the silicone rubber layer.

Obtained in this way. For lithographic printing plates that do not require dampening water,
Apply a negative film, place it in vacuum, and expose it to a high-pressure mercury lamp (
ORC Jet Li) 3000. using a distance of 1 m),
It was irradiated for 2 minutes. When the photopolymerizable adhesive layer in the unexposed area was eluted by washing with denatured ethanol, a good image was reproduced.

Claims (1)

[Claims] (1) A method for producing a lithographic printing original plate that does not require dampening water, characterized in that a non-aqueous dispersion polymer solution is applied to the uppermost layer of the lithographic printing original plate that does not require dampening water, and is dried to provide a coating layer having irregularities.