JPH0220871A - Damping-waterless planographic printing plate - Google Patents

Abstract

PURPOSE:To improve the scratching resistance at the time of development and plate wear by forming a primer layer of a layer formed by photocuring of a compsn. consisting of an epoxy resin and a photocation polymn. initiator. CONSTITUTION:This printing plate material is formed by forming the primer layer of the layer formed by photosetting of the compsn. consisting of the epoxy resin and the photocation polymn. initiator. The representative examples of the epoxy resin used for the primer layer include the reaction product of bisphenol A and epichlorhydrin, etc. Since the specific primer layer is provided to this material, the material has the nature that the adhesiveness between a base and a silicon rubber layer is extremely high even if the photosensitive layer is formed of a thinner film. The resulted damping-waterless planographic printing plate has the practicably high plate wear. Since the primer layer is cured not by heating but by light, the shorter time is necessitated for the primer layer to cure and the curing speed is high. The printing plate material having the scratching resistance at the time of development and the practicably good plate wear is obtd. in this way.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a lithographic printing plate material that does not require dampening water, and more specifically, a lithographic printing plate that does not require dampening water and has good scratch resistance during development and printing durability. Regarding materials.

[Prior Art] Conventionally, as a lithographic printing plate material that does not require dampening water (hereinafter referred to as "plate material" as necessary), a material in which a primer layer, a photosensitive layer and a silicone rubber layer are sequentially coated on a support is known. (Japanese Patent Publication No. 61-54219, Japanese Patent Publication No. 62-507
No. 60, No. 60-229031), that is, Special Publication No. 61-
No. 54219 and JP-A-62-50760 disclose a technique for providing a primer layer made of epoxy resin.
Further, Japanese Patent Laid-Open No. 60-229031 discloses a technique for providing a primer layer made of photodimerization type photocuring.

According to this prior art, it is possible to provide a lithographic printing plate material that does not require dampening water and has excellent printing durability due to the presence of the primer layer, excellent scratch resistance and abrasion resistance of the silicone rubber layer, and good developability.

[Problems to be Solved by the Invention] However, the above-mentioned conventional technology has a practical problem because printing durability decreases when trying to increase the reproducibility of small dot images by making the photosensitive layer thinner. . In particular, when stored under high temperature and high humidity conditions, the adhesion between the photosensitive layer and the silicone rubber layer deteriorates, resulting in a problem of decreased dot reproducibility, shadow area reproducibility, and printing durability.

Furthermore, when a compound that undergoes a photodimerization reaction is used as a composition for the photosensitive layer, there is a problem in that printing durability is extremely reduced.

Therefore, the object of the present invention is to provide a silicone rubber layer with good adhesion, scratch resistance during development, good printing durability in practical use, and a compound that undergoes a photodimerization reaction as a composition of the photosensitive layer. It is an object of the present invention to provide a lithographic printing plate material that does not require dampening water and exhibits excellent printing durability even when using dampening water.

[Means for Solving the Problems] As a result of intensive studies to achieve the above object, the inventors have arrived at the present invention.

That is, the dampening water-free planographic printing plate material according to the present invention is a dampening water-free planographic printing plate material that has a primer layer, a photosensitive layer, and a silicone rubber layer in this order on a support. It is characterized by being a layer formed by photo-curing a composition consisting of (a) an epoxy resin and (b) a cationic photopolymerization initiator.

[Function] Since the present invention is provided with the above-mentioned unique primer layer, it has the property that even if the photosensitive layer is made thin, the adhesion between the support and the silicone rubber layer is extremely high, and therefore the scratch resistance of the silicone rubber layer is improved. The resulting lithographic printing plate, which does not require dampening water, has excellent durability and abrasion resistance, and has a practically high printing durability. Furthermore, since the primer layer is photocured rather than heated, the time required to cure the primer layer is short and the curing speed is fast.

[Specific Structure of the Invention] The support of the present invention is preferably one that is flexible enough to be set in a normal lithographic printing machine and that can withstand the load applied during printing, such as aluminum, zinc, copper, steel, etc. Metal plates, metal plates plated or vapor-deposited with chromium, zinc, copper, nickel, aluminum, iron, etc. 1 paper, plastic films and glass plates, resin coated paper, paper covered with metal foil such as aluminum, hydrophilic Examples include treated plastic films and rubber. Among these, aluminum plates are preferred.

Typical examples of epoxy resins used in the primer layer of the present invention are as follows.

(1) Reaction product between bisphenol A and epichlorohydrin (2) Reaction product between novolak resin and epichlorohydrin (3) Reaction product between bisphenol F and epichlorohydrin (4) Reaction product between tetrabromobisphenol A and epichlorohydrin (5) Cycloaliphatic epoxy resin (compound that accommodates cyclohexene oxide group, tricyclohexene oxide group, cyclopentene oxide group) (6) Glycidyl ester epoxy resin (reaction product of polyhydric carboxylic acid and epichlorohydrin) ( 7) Glycidylamine-based epoxy resin (reaction product of amine and epichlorohydrin) (8) Heterocyclic epoxy resin (hydantoin-type epoxy resin with glycidylated hydantoin ring and triglycidyl isocyanurate with triazine ring) As epoxy resin In addition to this, any known epoxy resin, that is, any resin having an average of at least one epoxy group per molecule can be used.

Epoxy resins preferably used in the present invention are:
The above-mentioned cycloaliphatic epoxy resin is more preferably used in combination with other epoxy resins, such as bisphenol A-based epoxy resins.

Examples of the photocationic polymerization initiator used in the present invention include metallocene compounds represented by the following formula.

As the photocationic polymerization initiator other than the above-mentioned metallocene compound, a known cationic photoinitiator can be used. These are, for example, onium salts with weak nucleophilic anions. Examples of these include European Patent A-15
Heronium salts described under formula ■ in the specification of No. 3,904; iodosyl salts described under formula ■ in the same specification; Sulfonium salts 1 such as European Patent A-35,969,
44,274,54,509 and 164,314 or diazonium salts as described, for example, in U.S. Pat.

Reports of other conventional onium salt initiators include UV-curing (UV
-Curing), Science and Technology
d Tec-hnology), [Publisher: S, P, Pappas, Technology Marketing Corporation (Techno
Logy Marketing Corp, ), 64
2 Westover Ro
ad), Stanford,
Found throughout Connecticut (Connecticut, USA).

In the present invention, it is also preferable to use the above-mentioned initiator together with a sensitizer or peroxide. Examples of the sensitizer include anthracene, diethylthioxanthone, isopropylthioxanthone, etc., and examples of the peroxidant include cumene. There are hydroperoxide, di-tertiary-butyl peroxide, and tertiary-butyl peroxide.

In addition to the above, surfactants, plasticizers, reactive diluents, etc. can also be used in combination.

The composition ratio of the primer layer of the present invention is as follows. That is, the photocationic polymerization initiator is preferably 0.1 to 15.0 parts by weight, more preferably 0.1 to 5.0 parts by weight, and the sensitizer is 0.1 to 15.0 parts by weight, relative to 100 parts by weight of the epoxy resin. 5-3.
0 parts by weight is preferable, more preferably 0.2 to 1.0 parts by weight.
The amount of peroxide is preferably 0.1 to 10.0 parts by weight, more preferably 1.0 to 3.0 parts by weight.

The photosensitive material used in the photosensitive layer of the present invention is not particularly limited, and examples thereof include quinonediazide type positive photosensitive materials such as conventionally known O-naphthoquinone cyacyto compounds. Suitable O-naphthoquinone cyacyto compounds include naphthoquinone-(1,2)-diazide-(2)-sulfonic acid chloride and phenol or cresol-formaldehyde as described in U.S. Pat. No. 39,46,120. There are esters with resins. Other useful 0-naphthoquinone cyasito compounds include esters of pyrogallol-acetone resin and 0-naphthoquinone cyasitosulfonic acid chloride described in U.S. Pat. No. 3,635,709, and JP-A-55-76346. ,
Ester of polyhydroxyphenyl resin and O-naphthoquinone cyacytosulfonic acid chloride described in JP-A-56-1044 and JP-A-56-1045;
A homopolymer of p-hydroxystyrene or a copolymer of this and other copolymerizable monomers as described in No. 113305 is ester-reacted with O-naphthoquinone cyasitosulfonic acid chloride, published by Tokko Sho. Examples thereof include a reaction product of a polymer product of a styrene monomer and a phenol derivative described in No. 49-17481 and O-quinonediazide sulfonic acid, and an ester of polyhydroxybenzophenone and O-naphthoquinone cyasitosulfonic acid chloride.

A photosensitive composition containing such a quinone diazide type positive photosensitive material may optionally contain a binder. For example, a preferred example is a novolac resin soluble in an aqueous alkali solution. Examples of such novolac resins include phenol-formaldehyde resins,
Typical examples include cresol-formaldehyde resin, p-tert-butylphenol-formaldehyde resin, and phenol-modified xylene resin. The amount of the quinonediazide compound in the photosensitive layer is 10 to 50% by weight, more preferably 20 to 40% by weight.

The blending amount of the binder is 45 to 80% in the photosensitive layer composition.
% by weight, preferably 50 to 70% by weight.

Further, in the present invention, the following photosensitive substances can be used. For example, a diazo resin typified by a condensate of an aromatic diazonium salt and formaldehyde. Particular preference is given to salts of condensates of p-diazodiphenylamine and formaldehyde or acetaldehyde, such as reaction products of hexafluorophosphates, tetrafluoroborates, perchlorates or periodates with said condensates. Certain diazo resin inorganic salts and U.S. Patent No. 3,300. :1
Examples include diazo resin organic salts, which are reaction products of the condensate and sulfonic acids, as described in No. 09. Furthermore, diazo resins are preferably used together with binders. Various polymer compounds can be used as such a binder, but monomers having an aromatic hydroxyl group as described in JP-A No. 54-98813,
For example, N-(4-hydroxyphenyl)acrylamide, N-(4-hydroxyphenyl)methacrylamide, O-, Rin-1 or P-hydroxystyrene, o-,
Copolymer of m-1 or p-hydroxyphenyl methacrylate and other monomers, US Pat. No. 4,123,27
Polymers containing hydroxyethyl acrylate units or hydroxyethyl methacrylate units as a main repeating unit as described in No. 6, shellac,
Natural resins such as rosin, polyvinyl alcohol, polyamide resins described in U.S. Patent No. 3,751,257, linear polyurethane resins described in U.S. Patent No. 3,660,097, phthalated resins of polyvinyl alcohol, Epoxy resins condensed from bisphenol A and epichlorohydrin, celluloses such as cellulose acetate and cellulose acetate phthalate are included.

In addition, there are also those whose main component is a photosensitive polymer such as polycarbonate, which has a photosensitive group in the main chain or side chain of the polymer. (2- Examples include photosensitive polyesters derived from malonic acid compounds (probeliden) and difunctional glycols.

Further examples include aromatic azide compounds in which the azide group is bonded directly or via a carbonyl group or a sulfonyl group to an aromatic ring. For example, U.S. Pat.
Boriasitostyrene, polyvinyl-p-azidobenzoate, polyvinyl-p-azidobenzal, azidoarylsulfanyl chloride and unsaturated hydrocarbon polymers as described in Japanese Patent Publication No. 45-96!3 The reaction product with
No. 44-229, No. 44-22954 and No. 45-
Examples include polymers having sulfonyl azide and carbonyl azide, as described in No. 24915.

Furthermore, a photopolymerizable composition comprising an addition polymerizable unsaturated compound may also be mentioned. The present invention can also be applied to photosensitive compositions used in electrophotographic printing plates6. For example, electron donating compounds used in printing original plates using electrophotography described in JP-A-55-161250, phthalocyanine-based Examples include photosensitive compositions comprising pigments and phenolic resins.

Although the effects of the present invention can be achieved using any of the above-mentioned photosensitive substances, the present invention is particularly superior in that it has excellent printing durability even when a photodimerizable photosensitive substance is used.

In addition to the above, the photosensitive layer contains dyes (for example, Victoria Pure Blue BOH (manufactured by Hodogaya Chemical Co., Ltd.), Oil Blue 1603 (manufactured by Hodogaya Chemical Co., Ltd.) to make the image visible after exposure or development.
triphenylmethane type (manufactured by Orient Chemical Industry Co., Ltd.),
diphenylmethane dyes, etc.), alkyl ethers to improve coating properties (e.g., ethyl cellulose, methyl cellulose), fluorine-based surfactants, nonionic surfactants (e.g., Pluronic L64 (manufactured by Asahi Denka),
It may contain a plasticizer (for example, polyethylene glycol, tricresyl phosphate, acrylic acid or methacrylic acid polymer) and a stabilizer (for example, phosphoric acid, oxalic acid, tartaric acid, etc.) to impart flexibility to the coating film.

The silicone rubber used in the silicone rubber layer of the present invention is a linear organic polysiloxane having 1-order repeating units, a molecular weight of several thousand to several tens of edges, and an OH group in the main chain or at the end of the main chain. It is preferable that the amount of

-(-3i -09 where n is an integer of 2 or more, R is an alkyl group having 1 to 10 carbon atoms, a halogenated alkyl group, an alkyl group, a vinyl group,
Aryl group, silanol group (O11 group), R6
Preferably, 0% or more is methyl group. The silanol group (OH group) may be located either in the main chain or at the end of the main chain, and is preferably located at the end.

The silicone rubber useful in the present invention is obtained by a condensation reaction between such a silicone base polymer and a silicone crosslinking agent as listed below.

(1) R-5i(-OR') (2) R-8i+0Ac) (3) R-3i%0N=CR'z)gHere, R has the same meaning as R explained earlier, and R' is It is an alkyl group such as a methyl group or an ethyl group, and AC is an acetyl group.

These silicone rubbers are also available as Ichisaka products, such as YE-3085 manufactured by Toshiba Silicone Co., Ltd.

Other useful silicone rubbers can be produced by reacting the above-mentioned base polymers with silicone oils having primary repeating units, or by reacting silicone base polymers in which about 3% of R is vinyl groups. addition reaction,
Alternatively, it can also be obtained by a reaction between the silicone oils.

(In the formula, R has the same meaning as R above, I is an integer of 2 or more, and n is an integer of 0 or 1 or more.) In order to obtain silicone rubber by such a crosslinking reaction, the above-mentioned In addition to the ingredients, tin and zinc.

Organic carboxylates of metals such as cobalt, lead, calcium, manganese, etc.1 For example, dibutyltin laurate, tin (
II) Catalysts such as octoate, cobalt naphthenate, etc. or chloroplatinic acid are added.

It also improves the strength of silicone rubber, making it suitable for printing.

In order to obtain a silicone rubber that can withstand the frictional forces generated during operation, fillers can be mixed.

Silicone rubber mixed with a filler in advance is reprinted as silicone rubber stock or silicone rubber dispersion, and when it is preferable to obtain a silicone rubber film by coating as in the present invention, RTV or LTV silicone rubber is used. Disversion is preferred. An example of this is Syl Off 23.
There are silicone rubber dispersions for vapor coating such as 5RX-257 and Sl+2417.

In the present invention, it is preferable to use condensation and crosslinking type silicone rubber.

The silicone rubber layer preferably contains a silane coupling agent in order to further improve adhesiveness.

Examples of silane coupling agents include the following.

(a) HJCH2CHJHCCH2CH2CHzSi
(011:Hi):+(b) (:H,CHCH20(
C13Si(OCH3))\1 (c) 1ts((:Hz) 3si(OCH:+)
i(d) CH2-CH5i(0(:OCH:+)f
f(e)GHz-C-COO(CH2)+5i(OCH
3) iH3 (f) CL-(:H3I(OCLCL)z(g)
Hx N CH□CToNH(CHz)+5i(OCH
:+)z(CH3)(h)Chlorsilane In the present invention, in addition to the above-mentioned components, a small amount of a photosensitizer can be included in the silicone rubber layer.

The thickness of each layer constituting the plate material of the present invention is as follows. That is, the support is 50 to 400 JLm, preferably 10
0 to 1100p, and the primer layer preferably has a thickness of 0.1 to 100p, more preferably 1.0 to 15μm.

The photosensitive layer has a thickness of 0.05 to 10 JL, preferably 0.1 to 2
The silicone rubber layer has a thickness of 0.5 to 100 gm, preferably 1 to 40 gm.

In the present invention, a protective layer may be provided on the upper surface of the silicone rubber layer, if necessary.

The dampening water-free plate material of the present invention is manufactured, for example, as follows.

As a 0M light source, the primer layer is applied onto the support using a normal coater such as a reverse roll coater, air knife coater, Meyer bar coater, or a rotary coating device such as Whaler, and then the entire surface is exposed to light for photocuring. There are high-pressure mercury lamps and metal ferrite lamps. It is also preferable to heat the primer layer during or after exposure. Next, a composition solution to form a photosensitive layer is applied onto the primer layer, dried, and heat cured if necessary. If necessary, an adhesive layer may be provided on the photosensitive layer in the same manner as above.Next, a silicone rubber solution is applied on the photosensitive layer in the same manner, and the adhesive layer is applied at a temperature of usually 100 to 120°C for several minutes. Heat treatment is performed to fully cure the silicone rubber layer.

If necessary, a protective film is provided on the silicone rubber layer using a laminator or the like.

To obtain a printing plate using the plate material obtained as described above, a positive film, which is an original, is vacuum-adhered to the surface of the plate material.
Expose. As a light source for this exposure, a mercury lamp, a carbon arc lamp, a xenon lamp, a metal halide lamp, a fluorescent lamp, etc., which generate abundant ultraviolet light, are used. A photo-insolubilized portion is formed in the photosensitive layer by exposure. Next, when the unexposed area is eluted and removed using a developer and developed, the image area (concave area)
form. As the developing solution, those known as developing solutions for plate materials that do not require dampening water can be used. product name) or gasoline,
kerosene, etc.), aromatic hydrocarbons (toluene, xylene, etc.)
, or a halogenated hydrocarbon (such as trichlene) to which the following polar solvent is added is suitable.

Alcohols (methanol, ethanol, water, etc.), ethers (methyl cellosolve, ethyl cellosolve, butyl cellosolve, methyl carpitol, ethyl carpitol, butyl carpitol, dioxane, etc.), ketones (acetone, methyl ethyl ketone, etc.), esters ( Ethyl acetate, methyl cellosolve acetate, cellosolve acetate, carpitol acetate, etc.), and dyes such as crystal violet and astrazone red can be added to the developer to dye the image area simultaneously with development.

Development can be carried out by a known method, such as rubbing with a developing vat 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, and the surface of the primer layer is exposed, which becomes an ink receiving area.

The depth of the ink receiving portion may be only the thickness of the photosensitive layer and the silicone rubber layer, or may be only the thickness of the photosensitive layer or the silicone rubber layer.

If necessary, it is also preferable to embed an ink receptive material in the recess in order to reduce the depth of the ink receiving part (printing part).

[Effects of the Invention] According to the present invention, it is possible to provide a lithographic printing plate material that does not require dampening water and has a silicone rubber layer that has good adhesion, has good scratch resistance during development, and has good printing durability in practical use. . Further, even when a compound that undergoes a photodimerization reaction is used as the composition of the photosensitive layer, it has the effect of exhibiting excellent printing durability.

[Example]= The present invention will be explained in further detail by giving examples below.

Note that "parts" means "parts by weight" unless otherwise specified.

Example 1 A primer layer having the following composition was cured on a smooth aluminum plate which had been blood-removed by a conventional method, and the film thickness was 4. Coat to give OILm, heat and dry, expose and heat with a high pressure mercury lamp (10
0°C) and cured.

This curing time is 30 seconds, and conventional heat drying (usually 5
minutes).

Araldite GY250 (Bisphenol A epoxy resin manufactured by Ciba Geigy)
50 parts Araldite CY176 (cycloaliphatic epoxy resin manufactured by Ciba Geigy) 50 parts Irgacure CG24-61 (metallocene compound manufactured by Ciba Geigy) 3.0 parts Cumene hydroperoxide 2.5 parts Anthracene 0.25 parts Methyl cellosolve
800 parts of the following photosensitive composition was coated on the primer layer at a dry weight of 0.21 part m and dried at 120° C. for 35 seconds to form a photosensitive layer.

(1) p-hue nylene diacrylic acid ester and 1.4
-l=1 with dihydroxyethyloxycyclohexane
Photosensitive unsaturated polyester produced by polycondensation (photodimerization type)
10 parts (2) l-Methyl-2-benzoylmethylene-β naphthothiazoline 0.6 parts (co) Sumitone Cyanine Blue VH514 (phthalocyanine blue pigment manufactured by Sumitomo Chemical Co., Ltd.) 2 parts (4) Methyl cellosolve acetate 600 parts (5
) 300 parts of toluene Next,
Dry the following silicone rubber layer composition on the photosensitive layer!
Apply so that the weight is 2.0 l.

It was dried at 120°C for 4 minutes to obtain a silicone rubber layer.

Silicone rubber layer composition: 100 parts of dimethylpolysiloxane (molecular weight: approx. 100,000) having water-unfriendly groups at both ends; 3.5 parts: 1
-Methoxysilylpropyl-3,5-diallylisocyanure - 3.3 parts dibutyltin dioctanoate 3.3 parts Isopar G (manufactured by Esso Chemical Co., Ltd.) 1500 parts Sa1
A 2 gm single-sided matted polypropylene film was laminated to produce a plate material that did not require dampening water.

Developer composition Isopar H (manufactured by Esso Chemical Co., Ltd.) 25 parts Turfitz (manufactured by Clarei Soprene Chemical Co., Ltd.) 25 parts methanol
25 parts toluene
25 parts A positive film was vacuum-adhered to the top surface of the above plate material and exposed using a metal halide lamp.Then, the laminate film was peeled off, and rubbed with a development vat using the above developer to remove the unexposed photosensitive layer and silicone rubber. The layer was removed to produce a dampening water-less lithographic printing plate.

Next, the above printing plate was attached to a Heidelberg GTO printing machine with the dampening water supply device removed, and a TOY manufactured by Toyo Ink Co., Ltd.
OKING ULTRA TKU 7 When printed with Kuwa L/Su G red ink, so many prints with poor shadow area reproducibility were obtained up to the final print, and it was found that the printing durability was excellent. 40'C80%IIH
Good printing durability was also shown when using a printing plate stored for one week under the conditions below.

Example 2 Printing was performed in the same manner as in Example 1 using a quinone diazide compound in place of the photodimerizable photosensitive unsaturated polyester used as the photosensitive composition in Example 1, and the results up to the final printed matter were Printed matter with excellent shadow reproduction is so,
OOO sheets were obtained, and it was found that the printing durability was excellent. Also 4
Good printing durability was also exhibited when a printing plate stored for one week at 0° C. and 80% RH was used.

Comparative Example 1 Printing was carried out in the same manner as in Example 1 except that the primer layer composition of Example 1 was changed to the following, and only 10,000 prints with excellent shadow area reproducibility were obtained.

Epicoat 1001 (Bisphenol A epoxy resin manufactured by Shell Chemical Co., Ltd., epoxy equivalent: 450-5OO) 10
0 parts Methyltetrahydrophthalic anhydride 36 parts 2,4.
6-) Lis(dimethylaminomethyl)phenol
12 parts methyl cellosolve acetate 120 parts toluene
120 parts methyl ethyl ketone
120 copies Comparative Example 2 Printing was carried out in the same manner as in Example 1 except that the primer layer composition of Example 2 was replaced with the composition shown in Comparative Example 1. 25,000 prints with excellent shadow area reproducibility were obtained. I could only get it.

In addition, in this specification, Example 1 or 2 within the range described above
Printing was carried out in the same manner as in Examples 1 and 2 using photosensitive materials other than those used in Example 1, and the effects of the present invention were confirmed.

From the above, it can be seen that while the conventional primer layer has poor printing durability when a compound that undergoes a photodimerization reaction is used in the photosensitive layer, the printing durability of the present invention is extremely high regardless of the type of photosensitive material. It turns out to be excellent.

Claims (1)

[Claims] In a lithographic printing plate material that does not require dampening water and has a primer layer, a photosensitive layer, and a silicone rubber layer in this order on a support, the primer layer contains a composition comprising (a) an epoxy resin and (b) a photocationic polymerization initiator. A lithographic printing plate material that does not require dampening water and is characterized by a layer formed by photocuring.