JPS6214156A - Dry type photosensitive lithographic printing plate - Google Patents

Abstract

PURPOSE:To improve the inter-layer adhesive powder between a photosensitive layer and silicone rubber layer and to prevent the decrease of the inter-layer adhesive powder even after lapse of a long period of time by forming the silicone rubber layer by using a specific silicone rubber compsn. CONSTITUTION:The silicone rubberof the dry type photosensitive lithographic printing plate contg. the photodimerization type photosensitive layer and the silicone rubber layer contiguous to the photosensitive layer is formed of the silicone rubber compsn. contg. organopolysiloxane and reactive silane compd. having an allyl isocyanurate group. The amt. of the reactive silane compd. to be added is 0.5-10%, more preferably 1-5% by the amt. of the linear org. polysiloxane. The poor developability and image reproducibility are resulted if said compd. is excessively added to the compsn. The substantial adhesive power is not obtainable if the compd. is added too little.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a photosensitive plate used for dry lithography, that is, for the production of lithographic printing plates used without the use of dampening water.

[Conventional technology]

As a dry planographic printing plate for planographic printing without using dampening water, a photopolymerizable photosensitive layer is placed on an aluminum plate.
A structure in which a silicone rubber layer is applied thereon and a cover film is further laminated is known. This printing plate is made by vacuum-adhering a positive film onto a cover film and exposing it to light. After peeling off the cover film and developing it by rubbing it with a solvent, the exposed areas (non-image areas) are separated by a photosensitive layer and a silicone rubber layer. The interfacial adhesion of the layer increases, resulting in a strong ink repellent layer, and in the unexposed areas (image areas), the silicone rubber layer is removed, leaving only the photosensitive layer, to which ink adheres. Many types of dry lithographic printing plates have been proposed (
For example, Special Publication No. 44-23,042, Special Publication No. 46-
16044, Japanese Patent Publication No. 51-17081, Japanese Patent Publication No. 54-26923, Japanese Patent Publication No. 56-80046, and Japanese Patent Publication No. 55-22781). Among them, dry lithographic printing plates of the type using a photodimerizable photosensitive resin disclosed in Japanese Patent Publication No. 55-22781 are superior to dry lithographic printing plates of the type using a photopolymerizable photosensitive layer. As a result, it is less susceptible to the effects of oxygen during the plate-making and exposure processes. Therefore, in order to improve the vacuum adhesion of the original film to the photosensitive lithographic printing plate, the former has a structure in which a matte discontinuous layer is coated on a silicone rubber layer, or an extremely thin film with almost no ability to prevent oxygen permeation. Even with a structure in which a thin overcoat layer is applied on a silicone rubber layer,
In addition, even when an original film is laminated directly onto the silicone rubber layer and exposed in order to improve tone reproducibility, printing is sufficiently possible.

Furthermore, the type of dry photosensitive lithographic printing plate using a photodimerizable photosensitive resin is different from the type using a photopolymerizable photosensitive composition.
In comparison, it is less susceptible to the effects of exposure temperature during the plate making and exposure process, and has the feature that stable plate making is possible without fluctuations in sensitivity depending on the elapsed time from exposure to development and the temperature at that time.

However, due to poor adhesion between the silicone rubber layer, which is an ink repellent layer, and the photodimerizable photosensitive layer, it is necessary to provide an adhesive intermediate layer between the photosensitive layer/silicone rubber layer to bond them together, or to form a silicone rubber layer. Adding a silane coupling agent containing an aminoalkyl group to the silicone rubber composition, introducing hydroxyl groups etc. that are reactive with the silicone rubber layer into the photodimerizable photosensitive resin, drying the silicone rubber composition, etc. Various special treatments such as heat treatment were required during the curing process.

Among these methods, the method of providing an adhesive intermediate layer between the photosensitive layer and the silicone rubber layer to improve adhesion has stable adhesive strength and does not cause any problems even when stored for a long period of time (1 to 2 years). The developability of the resulting dry lithographic printing plate deteriorated, and the number of steps required for coating the adhesive intermediate layer increased, resulting in unsatisfactory manufacturing. In addition, the method of incorporating a silane coupling agent having an aminoalkyl group into a silicone rubber composition was considered to be a desirable method because the developability was greatly improved and the step of coating an intermediate layer could be omitted. Possibly because sufficient adhesive strength is not obtained, if left for a long period of time (6 months), the adhesive strength may deteriorate and sufficient image reproducibility may not be obtained. However, the problem was that the silicone rubber layer would fall off, making it impossible to obtain clear printed matter. Furthermore, the method of introducing a functional group that reacts with the silicone rubber layer into the photo-dimerizable photosensitive material itself has problems such as difficulties in synthesis, making it difficult to obtain a photo-dimerizable photosensitive material having the desired performance.

[Problem that the invention seeks to solve]

Therefore, an object of the present invention is to provide a dry photosensitive lithographic printing plate having a layer structure in which a silicone rubber layer is sequentially laminated on a photodimerizable photosensitive layer, without providing a single layer of primer between the photosensitive layer and the silicone rubber layer. The adhesive strength between the photosensitive layer and the silicone rubber layer is improved, and the adhesive strength between both layers does not decrease even after a long period of time, making it possible to obtain a plate that is fully satisfactory in terms of performance even after a long period of time. Another object of the present invention is to provide an excellent dry photosensitive lithographic printing plate in which the silicone rubber U forming the non-image area does not fall off.

[Means for solving problems]

When the silicone rubber layer provided on the photosensitive layer is formed using a silicone rubber composition containing as essential components an organopolysiloxane and a reactive silane compound having an allyl isocyanurate group, interlayer contact between the photosensitive layer and the silicone rubber layer occurs. We have found a system that can improve adhesive strength and that does not reduce interlayer adhesive strength even after a long period of time.

That is, the present invention provides a dry photosensitive lithographic printing plate comprising a photodimerizable photosensitive layer and a silicone rubber layer adjacent to the photosensitive layer, in which the silicone rubber layer comprises an organopolysiloxane and a reactive silane compound having an allyl isocyanurate group. A dry photosensitive lithographic printing plate is provided, characterized in that it is formed from a silicone rubber composition containing.

The dry photosensitive lithographic printing plate of the present invention must be flexible enough to be set in a normal lithographic printing machine and must be able to withstand the load applied during printing.

Therefore, typical substrates include coated paper, metal shells, plastic films such as polyethylene terephthalate, rubber, or composite substrates thereof. It is also possible to coat the surface of these substrates with a layer of primer or the like for prevention of halation and other purposes, thereby forming a support.

The photosensitive layer that can be used in the present invention may be of any type, including photopolymerizable resins and photocrosslinkable resins, as long as its solubility or swelling property in a developer changes before and after exposure, but as mentioned above, For this reason, it is particularly desirable to include a photodimerizable photosensitive resin.

Examples of the photodimerizable photosensitive resin used in the present invention include those shown below. That is, examples include polyesters, polycarbonates, polyamides, polyacrylic acid esters, polyvinyl alcohol derivatives, epoxy resin derivatives 11, etc., which contain polyesters in the main chain or side chain of the polymer.

In the above formula, R and R1 are alkyl groups having 1 to 10 carbon atoms, and R2 is hydrogen, norogen, an alkyl group having 1 to 10 carbon atoms, or a cyano group. The molecular number is not limited as long as it is soluble in the solvent, but it is generally advantageous to select it from a range of 1,000 to several tens of thousands. Particularly preferred examples of this polymer include photosensitive polymers containing a photosensitive group in the polymer main chain, such as p-phenylene diacrylic acid, as described in U.S. Pat. Photosensitive polyesters consisting of diols, photosensitive polymers such as those described in U.S. Pat. No. 2,956,878 and U.S. Pat. Photosensitive polyesters derived from synthetic glycol necks, U.S. Pat. No. 2,690,966, U.S. Pat.
Photosensitive polymers such as those described in the specifications of No. 732301, such as cinnamate esters of hydroxyl group-containing polymers such as polyvinyl alcohol, starch, cellulose, and their analogs, which become insolubilized by the action of actinic rays. can be mentioned.

In the present invention, the following photosensitizers may be included in the photosensitive resin layer. For example, US Pat. No. 2,610,120, US Pat. No. 2-670,285, US Pat.
No. 0966, No. 2732301, No. 2835656, No. 2956878, No. 3023100, No. 306
No. 6117, No. 3141770, No. 3173787, No. 3357831, No. 3409593, No. 341
No. 8295, No. 3453110, No. 3475617, No. 3561969, No. 3575929, No. 358
Those described in No. 2327, No. 3647470, No. 3721566, No. 3737319, etc. A specific example of a particularly useful sensitizer is Te1;! , 2-benzoylmethylene-1-methyl-β-naphthothiazoline, 5-nitroacenaphthene, β-chloroanthraquinone, 1,2-benzalanthraquinone, p,p'-tetraethyldiaminodiphenylketone, p,p' -dimethylaminobenzophenone, 4-nitro-2-90luaniline, and the like. The ratio of sensitizer used is 0.5 to 1 to the polymer.
The range of quintuple fingers% (hereinafter abbreviated as %) is preferable, but
A particularly preferred range is 2 to 8%.

Furthermore, it is also possible to add additives such as dyes, pigments, plasticizers, and polymerization inhibitors, if necessary.

The appropriate thickness of the photosensitive layer is about 0.1 to 10 μm,
In particular, the thickness of the photosensitive layer of the type that dissolves and removes the photosensitive layer is better to be as thin as possible from the viewpoint of tone reproducibility.
The thickness is preferably about 1 to 0.5μ.

The silicone rubber layer used in the present invention is mainly composed of a linear organic polysiloxane having a molecular weight of several thousand to several hundreds of thousands and having the following repeating units.

Here, R3 is an alkyl group having carbon'@1 to 1O or a phenyl group, but preferably 60% or more of R3 is a methyl group. Such linear organic polysiloxanes are generally made into crosslinked silicone rubber by adding a reactive crosslinking agent. Crosslinking agents used in so-called room temperature (low temperature) curing silicone rubber include acetoxysilane, which may or may not have a monovalent organic group bonded to a silicon atom;
Silanes such as ketoximesilane, aminoxysilane, amidosilane, alkoxysilane, hydroxysilane,
There are siloxanes, organo-hydrodiene polysiloxanes, etc. which are condensates of these with a low degree of polymerization. These crosslinking agents react with the terminal hydroxyl groups of the linear organopolysiloxane to form crosslinked silicone rubber, and at the same time improve the adhesion with the photosensitive layer. Contains 10%.

The present invention improves the adhesive strength of the photosensitive layer/silicone rubber layer by replacing part or all of these normally added crosslinking agents with a reactive silane compound having an allyl isocyanurate group or a partial hydrolyzate thereof. It is characterized in that the interlayer adhesion strength does not decrease even after a long period of time. Although the reason for this is not clear, it is presumed that the excellent performance of the present invention is obtained because the isocyanate group in the reactive silane compound exhibits special compatibility with the photosensitive layer.

Examples of the reactive silane compound having an allyl isocyanurate group used in the present invention include those represented by the following general formula.

(R4: A divalent bonding group consisting of carbon, dust, nitrogen, etc., such as -C3H, -, -C3H6-NH-C,H, -, etc.

R5: A functional group such as an alkyl group having 1 to 3 carbon atoms or a phenyl group, and a dihydrolyzable group. Incidentally, R6 or R7 represents an alkyl group having 1 to 3 carbon atoms or a substituted alkyl group.

a = 1-2, n = 1-3) As the reactive silane compound having an allyl isocyanurate group, the above-mentioned ones are preferable, but other compounds can also be used. In addition, the amount of addition of the raw silane compound for reaction 1 is 0.5 to 10% relative to the linear organic polysiloxane.
% is preferably 1 to 5%. If the amount added is too large, developability will be inhibited and image reproducibility will deteriorate. On the other hand, if the amount added is too small, sufficient adhesive strength cannot be achieved.

A small amount of a metal organic carboxylate such as tin, zinc, or lead may be added to the silicone rubber composition as a catalyst. Furthermore, 0 to 300 for silicone rubber compositions.
It is also possible to add reinforcing fillers such as % fumed silicone. Further, a photosensitizer similar to or similar to the one that can be added to the photosensitizer mentioned above may be included.

The I7 thickness of the silicone rubber layer formed from the above-mentioned silicone rubber composition is suitably about 0.5μ to IOμ. The thickness of the silicone rubber layer is preferably as thin as possible from the point of view of tone reproducibility; 3.
It is desirable to set it to 0μ.

Polyethylene terephthalate, polyethylene, polypropylene, polystyrene, polyvinyl chloride, with or without unevenness treatment for the purpose of protecting the surface of the silicone rubber-top dry photosensitive lithographic printing plate constructed as above, A thin protective film or sheet of polyvinylidene chloride, cellophane, etc. can be laminated.

Such protective film is removed before image exposure.

On the other hand, a protective film that is transparent enough to transmit ultraviolet rays and has a thickness of 30 μm or less in order to prevent blurring during exposure can be subjected to image exposure without removing the film. Also, Japanese Patent Application No. 148341/1983,
It is also possible to apply a treatment liquid or a water-soluble protective layer on the silicone rubber layer by the method described in No. 148342.

The dry photosensitive lithographic printing plate according to the present invention is exposed to light through a positive film, and then developed with a developing solution that dissolves the photosensitive layer in the image area, that is, the unexposed area, and removes the photosensitive layer in the image area and the silicone rubber layer thereon. Alternatively, only the silicone rubber layer in the image area may be removed by developing with a developer that selectively swells only the silicone rubber layer in the area corresponding to the image area. A dry lithographic printing plate can be obtained by any of the above development methods.

As the developer used in the present invention, those known as developers for dry positive type photosensitive lithographic printing plates can be used. For example, aliphatic hydrocarbons (hexane, heptane,
“Isopar E, HSG” (trade name of aliphatic hydrocarbons manufactured by Esso Chemical) or gasoline, kerosene, etc.), aromatic hydrocarbons (toluene, xylene, etc.), or halogenated hydrocarbons (triclene, etc.) Preferably, a polar solvent is added.

Alcohols (methanol, ethanol, etc.) Ether neck (methyl cellosolve, ethyl cellosolve, butyl cellosolve, methyl carpitol, ethyl carpitol, butyl carpitol, dioxane, etc.) Ketones (acetone, methyl ethyl ketone, etc.) Ester M (ethyl acetate, methyl cellosolve) acetate, cellosolve acetate, carpitol acetate, etc.) Also, water can be added to the above organic solvent-based developer, or the above organic solvent can be solubilized in water using an activator etc. 5) and used as the developer. I can do it.

Furthermore, dyes such as crystal violet and astrazone red can be added to the developer to dye the image area at the same time as development.

Development can be carried out by a known method, such as rubbing with a developing pad containing a developer as described above, or pouring a developer onto the printing plate and then rubbing with a developing brush. As a result, the silicone rubber layer and photosensitive layer in the image area are removed, exposing the surface of the substrate or primer layer, and that area becomes ink-receptive, or only the silicone rubber layer in the image area is removed and the photosensitive layer is exposed. The bottom part becomes the ink receiving part.

〔Effect of the invention〕

Although the dry photosensitive lithographic printing plate according to the present invention does not provide an adhesive intermediate layer between the photosensitive layer/silicone rubber layer,
The developability is significantly improved compared to the conventional method of providing an adhesive intermediate layer, and compared to the method of incorporating a silane coupling agent containing an aminoalkyl group without an acylisocyanurate group into the silicone rubber composition. It is also possible to significantly improve stability over time.

The present invention will be explained in detail below with reference to Examples.

〔Example〕

Example 1 The following composition for a single layer of primer was applied to a smooth aluminum plate degreased in a conventional manner to a dry weight of 0.5 g/m 2 and dried.

- Brimer footwear composition Photosensitive unsaturated polyester produced by 1:1 polycondensation of P-phenylene diacrylic acid ester and 1,4-dihydroxyethyloxycyclohexane
10 parts 1-methyl-2-benzoylmethylene-β-naphthothiazoline 0.6 parts flitl methyl cellosolve acetate 3001 bottle, 1 toluene
150 layers Next, the aluminum board coated with the above composition was manufactured by Nuark! IIET26V
LJDNS IJLTRA-PLVS FLIP-
After exposure for 30 counts using a TOP PLATE MAKER, the photosensitive composition shown below was coated on one layer of the primer at a dry weight of 0.25 g/m' and dried.

・Photosensitive composition: Photosensitive unsaturated polyester produced by l:1 polycondensation of P-phenylene diacrylic acid ester and 1,4-dihydroxyethyloxycyclohexane
10 parts by weight 1-methyl-2-benzoylmethylene-β-naphthothiazoline 0.6 parts by weight Sumitone Cyanine Blue VH514 (Phthalocyanine Blue Face 1 manufactured by Seikoku Kagaku Co., Ltd.) 2 parts by weight Methyl cellosolve acetate) 600 ff1f
Using 300 g/m of toluene, the following silicone rubber composition was coated on the photosensitive layer to a dry weight of 2.0 g/m' and dried to obtain a cured silicone rubber layer.

・Silicone rubber composition 100 parts by weight of dimethylpolysiloxane having hydroxyl groups at both ends (molecular weight: approx. 600,000) Methylhydrodienepolysiloxane having trimethylsilyl groups at both ends (molecular weight: approx. 2.500) 3.5 parts by weight 1 - Trimethoxysilylpropyl - 3.5-diallyl isocyanurate 3.3 parts dibutyltin dioctoate 2.0 parts by weight Isopar〇 (manufactured by Esso Chemical Co., Ltd.) 2000 parts by weight The silicone rubber layer obtained as described above A single-sided matte polypropylene film with a thickness of 12 μm was laminated on the surface of the dry photosensitive lithographic printing plate.

A positive film was placed on this original printing plate, and it was vacuum-adhered and transferred to the Nuark Co., Ltd. PLATE M using a KER for 30 minutes.
After the count exposure, the laminate film was peeled off and a developer consisting of 90 parts by weight of Isopar H (manufactured by Esso Chemical Co., Ltd.), 7 parts by weight of diethylene glycol monobutyl ether, 3 parts by weight of diethylene glycol 1,000 ethyl ether, and 5 parts by weight of diethyl succinate was used. When the film was immersed in water for 1 minute and lightly covered with a developing pad, the unexposed portions of the photosensitive layer and silicone rubber layer were removed.

In this way, it was possible to obtain a dry planographic printing plate that faithfully reproduced the image of the positive film over the entire surface of the printing plate. This is a Heidelberg GT with the dampening water supply device removed.
TOYOKING U manufactured by Toyo Ink is installed on the O printing machine.
When printed with LTRΔ TKU Aquares G black ink, clear printed matter with no stains was obtained.

On the other hand, after leaving the dry photosensitive lithographic printing plate still laminated with the above polypropylene film in a dark place for 6 months, it was exposed and developed in the same manner as above, and when printed, it was as clear and clean as it was immediately after production. A printed matter was published.

Comparative Example 1 1-)dimethoxysilylpropyl-1,3-diallylisocyanurate in a silicone rubber composition was converted to N-(β-
A dry photosensitive lithographic printing plate for comparison was obtained in the same manner as in the example except that the silane was replaced with (aminoethyl)-7-aminopropyltrimethoxysilane. Example 1 of this printing plate
When plate printing was carried out in the same manner as above, clear prints without stains were obtained.

However, when the comparative sample dry photosensitive lithographic printing plate was left in a dark place for 6 months and then exposed and developed in the same manner as above, the silicone rubber layer forming the non-image area fell off, making it impossible to use it for printing. No printed version was available.

Example 2/Comparative Example 2 A similar primer layer and a photosensitive layer were provided on a degreased smooth aluminum substrate in the same manner as in Example 1.

Next, a silicone rubber composition having the following composition was applied onto the photosensitive layer by dry smoke stacking to a coating density of 2.0 g/m', and was dried and cured.

Dimethylpolysiloxane having hydroxyl groups at both ends (molecular weight approx. 600,000) 100 parts 1 part by weight Methylmethoxypolysiloxane having methyldimethoxysilyl groups at both ends (molecular fi approx. 500) 7 parts by weight 1-trimethoxysilylpropyl-3 , 5-diallylisocyanure) 3.3 times 11 dibutyltin dioctoate 1.7 times 1! Isopar G (Esso Chemical Co., Ltd.%)
) 2000 heavy ff1R A single-sided matted polypropylene film having a thickness of 12 μm was laminated on the surface of the silicone rubber layer treated as described above to obtain a dry photosensitive lithographic printing plate.

This printing plate also showed the same stable aging properties of the raw plate as in Example 1.

Further, when the above printing plate was made according to the method of Example 1, left to be plated for 50 days, and then run through a printing machine, clear printed matter without stains was obtained.

On the other hand, the same as in Example 1 was used except that 1-trimethoxysilylpropyl-3,5-diallylisocyanurate in the silicone rubber composition was replaced with N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane. When the dry photosensitive lithographic printing plate prepared by the process was made and plated according to the method of Example 1, the silicone rubber layer in the image area fell off after being left for about 30 days, making it impossible to obtain clear printed matter. .

To Mr. Michibe Uga, Director General of the Patent Office, Month, Day, Showa 1
, Indication of the case Patent Application No. 153140 of 1985 2, Title of the invention Dry photosensitive lithographic printing plate 3, Relationship with the case by the person making the amendment Applicant name (520) Fuji Photo Film Co., Ltd.
Shin-Etsu Chemical Co., Ltd. 4, Agent 5゜Date of amendment order Voluntary 6, Subject of amendment Column 1 of detailed explanation of the invention in the specification, “Photopolymerization system” on page 2, line 8 of the specification is corrected to "photoadhesion."

2. On page 2 of the circular, line 17, after “cone rubber layer” there is “
Insert "Only".

3. "Photosensitive layer..." on page 2 of the circular, lines 17-18.
・It is something that you have. "In some cases, the photosensitive layer is exposed and becomes the image area, or the silicone rubber layer and the photosensitive layer are simultaneously removed and the support or primer layer is exposed and becomes the image area. In either case, ink may adhere to the image area. 94. Correct "dry photosensitive lithographic printing plate" on page 3, line 8 of the circular to "dry photosensitive lithographic printing plate."

5. “New compatibility” on page 13, line 20 of the circular is changed to “affinity”
I am corrected.

Claims (1)

[Claims] A dry photosensitive lithographic printing plate comprising a photodimerizable photosensitive layer and a silicone rubber layer adjacent to the photosensitive layer, wherein the silicone rubber layer contains an organopolysiloxane and a reactive silane compound having an allyl isocyanurate group. A dry photosensitive lithographic printing plate formed from a composition.