JPS6320341B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a lithographic printing plate that does not require dampening water, and more specifically to a lithographic printing plate that has excellent properties in terms of resolution, printing durability, etc. This invention relates to a method for manufacturing a printing plate for printing.

In lithographic printing, a plate is used that does not have clear heights on the plate surface like letterpress or intaglio, and has a printed area and a non-printed area on the same plane in appearance.This printing method involves the following process. It will be held in In other words, first of all, water and fat repel each other,
The non-image area is made hydrophilic by chemical or mechanical treatment, and the image area is made lipophilic by transfer of a fatty resin or photographic printing, and then water is transferred to the printing plate. After that, water is applied only to the hydrophilic non-image areas, and then ink is further transferred to this plate surface. In this way,
This ink does not adhere to the non-print areas where water is present, but only to the lipophilic print areas, so
This is then transferred to a substrate to obtain the desired printed matter.

However, in this lithographic printing method, for example, the transfer of the dampening water to the ink roller causes the ink to emulsify on the ink roller, which causes stains, and also The transfer to the printing material also causes a change in the dimensions of the printing material, so there is a major drawback that the printed image becomes unclear, especially in multicolor printing. In addition, in this lithographic printing method, in order to obtain printed matter with a constant color tone, it is necessary to maintain a constant balance between the amount of dampening water and the amount of ink. It is very difficult to maintain a balance, which has the disadvantage of causing variations in the color tone of the printed matter.

For this reason, attempts have been made to develop printing plates for lithographic printing that do not require dampening water in order to improve the above-mentioned disadvantages, but none of the plates known to date are sufficiently satisfactory for practical use. They are not yet able to show the characteristics they should have.

For example, a diazo photosensitive layer made of a diazo type photosensitive composition and a dimethylpolysiloxane rubber layer are formed on a substrate such as an aluminum plate, and then a positive film is further laminated thereon and then exposed. A method of insolubilizing the diazo photosensitive layer in the exposed areas, removing the diazo photosensitive layer in the non-exposed areas by development treatment, and then peeling off the dimethylpolysiloxane rubber layer in the non-exposed areas (Tokuko Sho)
44-23042), or on a substrate such as an aluminum plate, a diazo photosensitive layer, an adhesive layer, and a silicone rubber layer are sequentially formed, and then a negative film is superimposed on this layer and exposed. A method of obtaining a printing plate for lithographic printing by developing the photosensitive layer using photodecomposition and then peeling off the silicone rubber layer in the exposed area (Japanese Patent Publication No. 1973-
16044) is known. but,
In all of these methods, a non-photosensitive silicone rubber exists between the diazo photosensitive layer and the positive or negative film, so the pattern appearing on the positive or negative film cannot be accurately reproduced. Furthermore, since the silicone rubber layer is peeled off using changes in the solvent solubility of the photosensitive layer, the images formed by the silicone rubber layer after peeling off have poor edges and are not sharp. It has the serious disadvantage that it cannot be used as a commercially available product, and it also has the disadvantage of being complex in operation, since its manufacture involves the steps of successively depositing two or three layers on a substrate, exposing and developing it.

As a method to eliminate the above-mentioned drawbacks in the development operation, there are methods of destroying the silicone layer by electron beam, laser light, electric discharge, etc. (see Japanese Patent Publication No. 42-21879), and by scanning the silicone layer with glow or corona beam. How to make it lipophilic
8207) is known. According to this, by destroying the silicone layer with an electron beam, laser beam, electric discharge, etc., or processing it with a corona beam, offset printing can be performed without any developing operation and without dampening water. However, high energy is required to destroy the ink repellent layer of dimethylpolysiloxane and generate low molecular weight dimethylpolysiloxane, and the plate making apparatus becomes large-scale. Furthermore, when patterning the silicone layer, the silicone is thermally destroyed with high energy, which causes the edges of the image to swell, resulting in a loss of sharpness of the image, resulting in a reduction in resolution and print quality. Also,
When using a corona beam, the printing plate takes a long time to form an image by scanning the ink repellent layer, and special equipment is required.

The inventors of the present invention have comprehensively studied material selection and manufacturing methods, taking into account the above-mentioned drawbacks of conventional lithographic printing plates that do not require dampening water.
By selectively chemically treating the activated chemical species in a plasma state, the oil-repellent organosilicone changes to lipophilicity, and unlike corona discharge or flame treatment, this change occurs not only on the surface of the silicone layer but also inside the silicone layer. It can be processed in a short time with low energy, and high resolution can be obtained by using a photosensitive resin as a protective coating layer.In particular, it is possible to obtain high resolution by adding a relatively small amount of photosensitive silicone to this photosensitive resin. As a result, the surface tension of the photosensitive resin decreases and approaches the surface tension of the underlying organopolysiloxane cured film layer, thereby forming a resist layer with good wettability and adhesion to the organopolysiloxane cured film layer. The present invention was achieved based on the discovery that extremely high resolution can be stably obtained.

That is, in the present invention, a cured film layer of organopolysiloxane and a film layer of a mixed resin made of photosensitive silicone and other photosensitive resin are sequentially formed on one surface of a substrate, and then exposed to light and developed. After forming a pattern by subjecting this surface to plasma treatment with activated chemical species in a plasma state and then removing the coating layer of the photosensitive mixed resin, a cured organopolysiloxane film is formed on the substrate. The present invention relates to a method for manufacturing a printing plate for lithographic printing, which comprises forming a non-image area consisting of a layer and an image area consisting of a plasma-treated organopolysiloxane cured film layer.

The manufacturing method of the present invention and the lithographic printing plate obtained thereby have the following excellent advantages.

(1) Since a high-resolution photosensitive resin is used, a lithographic printing plate with higher resolution than conventional lithographic printing plates that do not require dampening water can be obtained.

(2) In order to improve the adhesion of the photosensitive resin layer to the organopolysiloxane cured film layer, the amount of photosensitive silicone added to the photosensitive mixed resin can be relatively small, so it is difficult to develop the photosensitive resin layer. The image quality is good and high resolution is maintained.

It should be noted that for the purpose of improving the adhesion mentioned above, it is possible to add a normal surfactant, but
In this case, during the development process, the surfactant may remain on the cured organopolysiloxane film, or the surfactant may be eluted from the resin in the exposed area, resulting in a decrease in developability and resolution. In addition, unless a large amount of surfactant is added, the wettability to the lower layer will not improve, and even with this, sufficient improvement in adhesion cannot be expected.

(3) When a mixed resin consisting of photosensitive silicone and other photosensitive resin is used as the photosensitive resin, the compatibility between the photosensitive resin and the photosensitive silicone increases, and a more uniform coating can be obtained. Furthermore, since the photosensitive silicone is also developed at the same time as the photosensitive resin, even higher resolution can be obtained.

(4) In addition, by using photosensitive silicone, which has good adhesion to the organopolysiloxane cured film layer, as a coating layer mixed with other photosensitive resins, the adhesion of both layers is further improved, and the printing plate becomes easier to handle.

(5) By selecting the photosensitive resin, you can freely choose between negative and positive plate materials.

The present invention will be explained in detail below.

First, the present invention will be explained based on the drawings.
The figure is a partially enlarged sectional view schematically illustrating the structure of a printing plate for lithographic printing obtained by the method of the present invention. and an ink-receptive layer 3 (image area) consisting of an organopolysiloxane cured film layer subjected to plasma lipophilic treatment.

Next, a method for manufacturing a lithographic printing plate of the present invention will be explained. As shown in FIG.
After providing the film with a thickness of 2 to 50 μm,
As shown in FIG. 2, a protective layer (coating layer of photosensitive mixed resin) 5 is provided in a pattern on the organopolysiloxane cured film layer 4. As shown in FIG. Next, when plasma lipophilization treatment is performed, the protective layer 5 is treated as shown in FIG.
The organopolysiloxane cured film layer in the areas where it is not provided is modified and made lipophilic, thus forming the ink-receptive image area 3. Thereafter, the protective layer 5 is removed to obtain the lithographic printing plate shown in FIG. FIG. 5 shows the ink 6 adhered to the surface of the planographic printing plate obtained as described above.

The substrate used is one that is not affected by oxidation, etching, or photodegradation reactions caused by ultraviolet light generated by plasma due to plasma lipophilic treatment. Specific examples thereof include copper plates, aluminum plates, A metal plate such as a stainless steel plate, a zinc plate, an iron plate, a nickel-plated copper plate or iron plate, or a chrome-plated iron plate is used. Furthermore, various plastic films such as polyester, polypropylene, polyethylene, etc., the above-mentioned various plastic films with metal such as aluminum vapor-deposited on one side, and the above-mentioned various plastic films with metal foil such as aluminum bonded are also available. It can be used by reinforcing the back side with a metal plate.

The organopolysiloxane used to form the organopolysiloxane cured film layer on the substrate is desirably one that has excellent strength, abrasion resistance, good printing durability, and strong ink repulsion properties, and contains polydimethylsiloxane as the main component. Various thermosetting silicones are preferably used. Thermosetting silicones come in one-component and two-component types, and the two-component type cures with Si-OH, Si-OR, Si-H, and Si.
This is due to a catalytic crosslinking reaction between siloxanes having reactive groups such as -CH= _CH2 , and crosslinking reactions such as dehydration condensation, dealcoholization condensation, dehydrogenation condensation, and addition polymerization occur. One-component curing reacts with moisture in the air to cause a condensation curing reaction, and includes deacetic acid type, deamined type, dealcoholized type, and deoxime type. These are applied to one surface of the substrate by dissolving them in a suitable solvent such as benzene or toluene, applying them by a spin coating method, dipping method, dripping method, etc., and then heating and drying.

In order to form a uniform film of the cured organopolysiloxane film layer, the surface of the substrate is cleaned in advance by an appropriate method, and if necessary, the surface is roughened.
It is desirable to improve the adhesion with the coating.
In addition, it is advisable to apply a primer to the surface of this substrate in advance to improve adhesion with the film. Examples of this primer include vinyltris(2-methoxyethoxy)silane, 3-glycidoxypropyltritri Methoxysilane, 3-methacryloxypropyltrimethoxysilane, N-(3-
Silanes such as (trimethoxysilylpropyl) ethylenediamine, 3-aminopropyltriethoxysilane alone or mixtures thereof, as well as their partial hydrolysates or cohydrolysates, are used, and these can be applied by spin coating, rod coating, brush coating, etc. It is applied by conventional methods such as painting or spraying.

After forming a cured film layer of organopolysilosane on a substrate as described above, a coating layer of a mixed resin consisting of photosensitive silicone and other photosensitive resin is formed on this layer. Conventionally known photosensitive resins other than silicone-based resins may be used, including cinnamic acid-based photosensitive resins (TPR made by Tokyo Ohka Co., Ltd., and Kodatsu Co., Ltd.).
KPR, etc.), cyclized rubber photosensitive resin (manufactured by Tokyo Ohka Co., Ltd.)
OMR, Fuji Pharmaceutical Co., Ltd. FSR, etc.), azizo photosensitive resins (Fuji Pharmaceutical Co., Ltd. FPER, etc.), and diazo photosensitive resins (Supure Co., Ltd. AZ, Tokyo Ohka Co., Ltd. OFPR, Fuji Pharmaceutical Co., Ltd. FPPR, etc.), etc. is exemplified.

The amount of photosensitive silicone added to the photosensitive resin can sufficiently obtain the desired effect with a relatively small amount, and is usually 1 to 15% by weight.

Specific examples of the photosensitive silicones include organopolysiloxanes having siloxane units bonded to maleimide groups or maleimide groups containing substituent atoms or groups (Japanese Patent Application Laid-Open No. 1983-1989-1).
No. 120804, No. 51-125277, No. 52-13907, No. 120804, No. 51-125277, No. 52-13907, No.
52-105002, 52-116304, etc.), organopolyxyloxanes having siloxane units bonded with acryloxy groups or acryloxy groups containing substituted atoms or groups (see JP-A-48-16991,
No. 48-19682, No. 48-21779, No. 48-23880,
No. 48-47997, No. 48-48000, No. 48-83722,
No. 51-34291, No. 51-52001, No. 52-105003
No. 52-105004, No. 52-113805, No. 52-
113801, etc.), mixtures of organopolysiloxanes having mercapto group-containing siloxane units and organopolysiloxanes having vinyl group-containing siloxane units (see JP-A-53-17405, etc.), organopolysiloxanes having vinyl group-containing siloxane units, etc. Mixtures of polysiloxanes and organohydrodiene polysiloxanes (see JP-A-53-15907, etc.);
139504, etc.), a mixture of an organopolysiloxane having an acryloxy group-containing siloxane unit and an organopolysiloxane having a vinyl group-containing siloxane unit (see JP-A-52-139505, etc.)
Examples include.

The coating layer of the photosensitive mixed resin may be formed on the cured organopolysiloxane film layer by a conventional spin coating method, brush coating method, rod coating method, etc. There are no restrictions.

The coating layer of the photosensitive mixed resin is patterned by exposure and development, and this patterning can be done by a normal photosensitive resin plate making method, which allows the exposed portions of the cured film layer of organopolysiloxane and A protective layer portion made of a photosensitive resin layer is formed.

Next, the method of the present invention plasma-treats the patterned surface formed as described above with activated chemical species in a plasma state. Through this plasma treatment, the exposed portions of the cured film layer of organopolysiloxane are rendered oleophilic and become ink receptive image areas.

In order to make the cured film layer of organopolysiloxane oleophilic by the above plasma treatment, plasma oleophilic treatment using an inert gas such as argon, helium, or neon or an active gas such as oxygen or air is good. . Plasma lipophilization treatment is said to involve a complex combination of four types of changes: (1) etching, (2) chemical modification, (3) crosslinking, and (4) polymerization. Electron microscopy and infrared absorption measurements show that during plasma lipophilization treatment using active gas or active gas, surface etching does not occur, but mainly chemical modification of the cured organopolysiloxane film layer, that is, active chemical species in the plasma state. By colliding with the cured film surface of organopolysiloxane, alkyl radicals are eliminated, silicon radicals are generated, organopolysiloxane becomes three-dimensional due to crosslinking, and hydroxyl groups and carbonyl groups are generated due to oxidation of alkyl groups, etc. It is thought that the cured film of organopolysiloxane becomes lipophilic. Furthermore, these reactions proceed not only on the surface of the cured organopolysiloxane film layer, but also quite deep inside the cured film layer depending on the processing time. It is presumed that this is because the cured organopolysiloxane film layer generally has high gas permeability, so that the active chemical species reach the inside of the layer.

On the other hand, corona treatment and flame treatment only work on the surface, and this effect is usually lost by simply rubbing it with your hands or cloth. In contrast, in the plasma treatment according to the present invention, the effect is not lost even if the treated film is rubbed to the point of wear.

The low-pressure atmosphere for forming plasma-activated species can generally be air, but Ar, Ne, He, etc.
Inert gases such as O ₂ , N ₂ , NH ₃ , CO ₂ , and active gases such as fluorinated hydrocarbon gases can be used.

The plasma lipophilization treatment time varies depending on the conditions, but for example, under the conditions of 0.03 Torr and 300W, the cured film layer of organopolysiloxane is effectively rendered lipophilic in 30 seconds or more; If it exceeds 1 minute, the protective layer will deteriorate due to the etching effect, which is not preferable.

After plasma treatment, to remove the photosensitive mixed resin layer (protective layer), in the case of photoresist, it is not preferable to use a substance that would destroy the cured organopolysiloxane film layer, such as strong acid or strong alkali, and use acetone. , ethyl cellosolve, toluene, or other solvents.
For example, TPR manufactured by Tokyo Ohka Co., Ltd. can be removed using ethyl cellosolve, and FPER manufactured by Fuji Pharmaceutical Co., Ltd. can be removed using a ketone solvent such as methyl ethyl ketone or cyclohexanone. Even more
For photosensitive resins such as AZ and FPPR, alcohol,
It can be removed with a ketone solvent.

As shown in FIG. 4, the lithographic printing plate manufactured as described above consists of an image area 3 that has been subjected to plasma treatment and an ink-repellent non-image area 2 that is made of a cured film layer of organopolysiloxane. structure and has high resolution. When ink is supplied to this printing plate from an ink roller, the ink is transferred only to the plasma-treated image area 3, making it possible to perform planographic printing without the need for dampening water.

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

Example 1 Organopolysiloxane KS774 (trade name, manufactured by Shin-Etsu Chemical Co., Ltd.) was coated on a degreased and cleaned aluminum plate so that the film thickness after drying was 10μ, dried,
After heat curing, the composition formula is written on this side. A diazo photosensitive resin containing 5% by weight of a maleimide group-containing organopolysiloxane represented by
FPER100 (trade name manufactured by Fuji Pharmaceutical Co., Ltd.) was applied by a spin coating method.

Next, a positive original is placed in close contact with the original, exposed, developed to form a pattern, and subjected to plasma treatment for 10 minutes under the conditions of 2 torr and 300 W in the atmosphere, and the photosensitive resin layer is removed with methyl ethyl ketone for lithographic printing. A printing plate was obtained.

When this printing plate was used for printing with a lithographic printing machine (KOR printing machine manufactured by Heidelberg), it showed a printing durability of 50,000 sheets.

Example 2 In Example 1, except that diazo photosensitive resin FPPR700 (product name manufactured by Fuji Pharmaceutical Co., Ltd.) was used instead of FPER100, coating was carried out on the cured film layer of KS774, and then a negative original was coated. After contact and exposure, a pattern was formed by development, and plasma treatment was performed in the same manner as in the previous example, resulting in a lithographic printing plate having a printing durability of 50,000 sheets.

Example 3 Composition formula Added 5% by weight of photosensitive silicone shown in
A printing plate for lithographic printing was prepared in the same manner as in Example 1 except that FPER100 was used for the photosensitive resin layer.

This printing plate showed a resolution of 7% to 97% at 200 lines and had a printing life of 50,000 sheets.

Example 4 After applying KS774 on a polyester film whose back side was reinforced with an aluminum plate and curing it with heat, the composition formula was applied on top of it. A cinnamic acid-based photosensitive resin TPR containing 5% by weight of photosensitive silicone (trade name of Tokyo Ohka Co., Ltd.)
After coating and patterning, plasma treatment was performed in the same manner as in Example 1, and a lithographic printing plate with a printing durability of 50,000 sheets was obtained.

Example 5 A polyester film having the composition formula Added 5% by weight of photosensitive silicone shown in
When FPPR700 was applied and plasma treatment was performed in the same manner as in Example 2, a lithographic printing plate having a resolution of 7% to 97% at 200 lines and a printing life of 50,000 sheets was obtained.

Example 6 15% toluene solution of α,ω-dihydroxydimethylpolysiloxane with siloxane polymerization degree of 500 247
(parts indicate parts by weight, the same applies hereinafter) and 60 parts by weight of a 15% toluene solution of a hydrolysis product of phenyltrichlorosilane are mixed, and to this, 0.25 parts of 3-methacryloxypropyltrimethoxysilane and dibutylhydroxytoluene are mixed. After adding 0.01 part of dibutyltin dilaurate and 0.1 part of dibutyltin dilaurate, a condensation reaction was carried out at the reflux temperature of toluene, and the reaction was continued for 8 hours while removing the produced water. A polymer was obtained.

The diazo photosensitive resin AZ-111S (trade name manufactured by Syupre) containing 5% by weight of the above photopolymerizable organopolysiloxane was applied onto a cured film of KS774 provided on a degreased and cleaned aluminum plate, and after drying,
When a printing plate for lithographic printing was made in the same manner as in Example 2, this printing plate showed a printing durability of 50,000 sheets.

[Brief explanation of the drawing]

Figures 1 to 4 are partially enlarged cross-sectional views of successive steps showing the process for producing the printing plate for lithographic printing of the present invention, and Figure 5 is a diagram showing ink attached to the surface of the printing plate of the present invention. It is a partially enlarged sectional view showing the state. DESCRIPTION OF SYMBOLS 1...Substrate, 2...Non-image area consisting of an organopolysiloxane cured film layer, 3...Image area consisting of an organopolysiloxane cured film layer whose surface has been plasma treated, 4...Organopolysiloxane cured film Layer, 5... protective layer, 6... ink layer.

Claims (1)

[Claims] 1. A cured film layer of organopolysiloxane and a mixed resin film layer consisting of photosensitive silicone and other photosensitive resin are sequentially formed on one side of the substrate, and then exposed and developed to form a pattern. After forming this surface, a non-image layer consisting of an organopolysiloxane cured film layer is formed on the substrate by plasma treating the surface with activated chemical species in a plasma state and then removing the coating layer of the photosensitive mixed resin. A method for producing a printing plate for lithographic printing, comprising forming a line portion and an image portion consisting of a plasma-treated organopolysiloxane cured film layer.