JPS61132958A - Electrophotographic lithographic plate material - Google Patents

Abstract

PURPOSE:To prevent the deterioration of image quality and to enhance the printing resistance of a printing plate by incorporating a silane coupling agent in an interlayer between a substrate and a photoconductive layer to enhance water and solvent resistances of the interlayer. CONSTITUTION:The interlayer formed between the substrate and the photoconductive layer contains 1-15wt% silane coupling agent represented by the general formula: RnSiX4-n in which R is one of 1-30C aliphatic, cycloaliphatic, aromatic, and heterocyclic org. substituents, and at least one of R is a chemically active group, such as vinyl, glycidyl, and mercapto, (n) is 1 or 2, and X is halogen, amino, hydroxy, or the like. A modified silanol compd. produced by hydrolyzing these groups causes a condensation reaction to cross-link synthetic resins and polymers and to give the high resistances to water and solvents.

Description

DETAILED DESCRIPTION OF THE INVENTION Fields of Application of the Invention The present invention relates to electrophotographic lithographic printing return materials.
This invention relates to an improved electrophotographic printing plate material with little deterioration in image quality and excellent printing durability.

Conventional technology In recent years, the development of small offset printing presses and.

The development of automated printing equipment (this is the mainstream of light printing).

It is becoming dominated by offset printing.

Regarding this elegant printing plate material for offset printing,
Many research and developments have been carried out, and various materials have been proposed and are being put into practical use. These offset printing plate materials have a GW support a and a photoconductive layer, but in particular, electrophotographic lithographic printing plate materials that use zinc oxide as the main component of the photoconductive pigment and have a conductive layer at the bottom are inexpensive. It is the most popular light printing plate material because it has a simple plate-making process.

Preparing an electrophotographic printing plate from the printing plate material
The printing plate material is subjected to corona charging, exposure, development, and fixing treatment in a desired pattern using a plate making machine to form a photo-4-electronic image of the printing plate material (this forms a visible image of the desired pattern).

In general, there are two types of development processes: a dry development method that uses a mixture of toner and a carrier such as iron powder as a developer, and a wet development method that uses a T developer in which the toner is dispersed in an organic solvent such as Isopar.

(Wet development method described above) In addition, the resulting printed matter has good midtone reproducibility when heated, has excellent resolution, requires short platemaking time, and does not require a correction process. , and other advantages. This wet development method is most widely used for making electrophotographic lithographic printing plates.

Electrophotographic printing plate material pledge: The above-mentioned techniques and printing plate manufacturing processes are suitable, and the resulting images are also of high quality.
It is required that it be shown, but that alone is 1;
It is also required that the printing plates obtained therefrom have excellent printing properties.

The fixed lithographic printing plate manufactured through the development process must be capable of making its non-image areas desensitized. Makuhei printing plate materials.

It is advantageous to treat the surface of the exposed dimensional conductive layer with an etching solution, which makes it possible to make the non-image areas hydrophilic, and also to make the printing plate surface hydrophilic. It is necessary to have excellent water resistance in contact with the material.

In view of the above two requirements, it is known that an intermediate layer is provided between the photoconductive layer and the photoconductive layer to improve water resistance.

Generally used as an intermediate layer in electrophotographic lithographic printing plate materials.

It is required to have the following characteristics.

(I) Good barrier properties.

(2) Excellent solvent resistance. (It must not be affected by the solvent of the photoconductive layer paint.) (3) It must have excellent water resistance.

(4) It must have an appropriate electrical resistance value (1×10 g to 9×10” Ω-cm at 20″C, 65RH).

However, solvent resistance and water resistance are mutually contradictory properties, and it is therefore important to maintain a balance between the two, and various efforts have been made in this regard.

For example, synthetic resin emulsions, hydrophilic polymers, and water-resistant agents (Gliozal, urea resin, melamine resin, etc.)
It is known that an intermediate layer using
No. 02). However, this intermediate layer is unsatisfactory in terms of water resistance.

Furthermore, formalin or glyoxal contained in the waterproofing agent flea is liberated from the intermediate layer over time and adsorbed to the surface of the zinc oxide particles in the photoconductive layer, degrading the photoconductive layer, and
Silane coupling in the photoconductive layer was proposed in Japanese Patent Application Laid-open No. 96231/1983, where the problem of burrs hindering the oxygen reabsorption of the photoconductive pigment after irradiation with light and worsening the exposure property. It is disclosed that an agent is included. This improves the photosensitivity of the photoreceptor for copying and the adhesion between the photoconductive layer and the support, thereby improving printing durability. However, the idea of using silane coupling IFIl for the intermediate layer was completely unknown before the present invention.

Problems to be Solved by the Invention The present invention solves two problems in conventional electrophotographic printing plate materials, such as poor image quality due to aging and poor printing durability. It is.

Means for Solving the Problems and Their Effects The electrophotographic printing plate material of the present invention (I゜support, a photoconductive layer containing a photoconductive pigment and an insulating binder, and the support and It is characterized in that it has an intermediate layer formed between the photoconductive layer and the intermediate layer contains a silane coupling agent.

The support used in the present invention (for example, paper) is formed from laminated paper made by laminating aluminum foil or polyethylene film, synthetic paper, etc.
It has a thickness of about 0.00 to 170 μm. The photoconductive layer q contains a conductive pigment and an insulating binder.

Photoconductive pigments such as zinc and titanium oxide are used as photoconductive pigments.1. Ru. As an insulating binder, hydrophilic acrylic ester copolymers and methacrylic ester copolymers are generally used to prevent scumming during the printing process.

Vinyl acetate copolymers, silicone resins, and butyral resins are used. In each of the above copolymers and resins, functional groups such as acrylic acid, methacrylic acid, maleic acid, and itaconic acid are used as copolymer components to improve image quality, coating properties, and mechanical strength of the coating film. It will be done.

The photoconductive layer may also contain a sensitizing dye.

In the printing plate material of the present invention, an intermediate layer containing a 7-run coupling agent is formed between the support and the photoconductive layer.

There is no particular limitation on the type of silane coupling agent used in the present invention, but in general, the following general formula (I): % formula %) [However, in the above formula, R is an aliphatic compound having 1 to 30 carbon atoms. , 7tlJj selected from cycloaliphatic, aromatic and heterocyclic organic substituents, and at least one of the organic substituents represented by R″'C 1; is a chemically active group; Meri,
n represents an integer of 1 or G12, and X represents a hydrolyzable substituent.

A chemically active SG2.91I represented by 14 in the above general formula (I), such as a vinyl group or a glycidyl group.

Mercapto group, amino group, epoxy group, halogen group, 2
Containing engineered ester groups, as well as the above groups and atoms [
It can be selected from il-substituted alkyl groups.

Other organic substituents represented by R include, for example, N-β(aminoethyl)-γ-aminopropyl group, and L
and γ-methacryloxypropyl groups;
Cycloaliphatic substituents such as r-anilinofurovir group; N-
Aromatic substituents such as β~(N-hinylhensylaminoethyl-r-aminopropyl group), and heterocyclic substituents such as L and octadecyldimethylammonium chloride.

In addition, examples of the hydrolyzable substituent represented by
There are alkoxy groups such as V.

X amount G2,5 of the intermediate layer of the present invention: J/en ~ 15 g/lv
? It is preferable that the range dGCf be 5&/-~lol
/rr? More preferably, it is within the range of

Amount G of silane coupling agent contained in the intermediate layer;

It is preferably within the range of 1 to 15% by weight, and 5 to 1% by weight.
It is preferable to keep the weight within the range of 0 weight.

In the intermediate layer of the present invention, the 7-run coupling agent ◆ is effective as a water resistant agent and a solvent resistant agent.
For example, chemically active groups in the silane compound, such as amino groups, vinyl groups, epoxy groups, mercapto groups, or halogen atoms, cause a crosslinking reaction with casein to make the intermediate layer water resistant, and the silane compound Hydrolyzable substituents such as methoxy groups or ethoxy groups are hydrolyzed and modified into silanol groups, and the modified silanol (arsenol) undergoes a condensation reaction to form the synthetic resin and the highly hydrophilic This is due to crosslinking of molecules, etc.The above L
Due to the crosslinking reaction, the resulting intermediate layer exhibits excellent water resistance and solvent resistance.

In the electrophotographic printing plate material of the present invention, G.

A conductive 11L layer may be formed on the back surface of the photoconductive layer.

The conductive layer is made of a conductive material, such as polydiallyldimethylammonium chloride and a complex quaternary ammonium-type compound of polyvinyldimethylamthonium chloride, polyacrylic acid, sodium polystyrene sulfonate, ammonium polystyrene sulfonate, etc. It contains a binder such as polyvinyl alcohol, vinyl acetate resin, acrylic resin, styrene-butadiene resin, and the like. Conductive layer weight 5-15j
j/rr? It is preferable that the temperature is within the range of .

The intermediate layer of the present invention generally contains an inorganic filler selected from clay, Merck, calcium carbonate, mica, silica, etc. together with a silane coupling agent, polycrethane, acrylic resin, vinyl acetate, etc. based resin,
It contains a nonapolymer material selected from styrene-butadiene resin, polyvinyl alcohol resin, casein, gelatin, and the like.

To produce the printing plate material of the present invention, an intermediate layer coating containing the required components and a solvent is coated on one surface of the support and dried;
Further, a photoconductive layer coating material containing the necessary components and a solvent (for example, ethyl acetate, butyl acetate, toluene or xylene) is coated thereon and dried.

Example The present invention will be further explained with reference to Examples below.

Example 1 An electrophotographic printing plate material was prepared using the steps described below, a printing plate was made from it, and its properties were measured and evaluated.

(II) On one side of a base paper with a basis weight of t00 Jil/m', a barrier layer with the following composition was formed by size and press treatment to a weight of 2 g/cm (dry coating weight), and 80 parts of polyvinyl alcohol ( Solid content weight) Sodium polyacrylate 20 parts (yz) (2; Apply an intermediate layer paint of the following composition to the barrier layer surface of the above-mentioned size and press-treated regular base paper (thickness 110μ), dry it and apply it after drying. quantity io
A friend who forms the middle layer of 17rrz.

- 40 parts (by weight) polyurethane aqueous dispersion (-1,40 parts (f) casein aqueous solution
lO part CI) Silane coupling (sauce) 2
10 parts (l) Japan, Trademark: Azerax 3-1071%, manufactured by Hodogaya 1 Higaku (+112), Trademark: SH6040, manufactured by Toshi Silicone (3) The surface of the intermediate layer A photoconductive layer paint having the following composition was applied thereon and dried to form a photoconductive layer with a dry coating weight of 259/rr?9.

Photoconductive zinc oxide (13,100 parts (by weight)) Silicone resin (30 parts (I)) Rose Bengal
0.1 part CI) Toluene 1
50 copies CI)gl("+3"""Trademark: 5AZEX
2000. Sakai Chemical Co., Ltd. Trademark: KR-211, Shin-Etsu Chemical Co., Ltd. Coating and drying, dry coating amount 8g/rr? forming a conductive layer.

Polyvinyl alcohol (-1,30 parts (by weight)) Vinyl acetate resin (-1,650 parts (I)) Quaternary ammonium type cavity molecule conductive agent (4 to 1,720 parts (l)) Stain (◆) 5... Trademark :T-330, Nippon Gosei Kagakuko 1-+,・-・-・-Trademark: Cevian A -52 parts 2%
Daicel type (・) 7... Trademark: Chemistat 5500, manufactured by Sanyo Chemical (5) The obtained printing plate material was subjected to acclimatization treatment for 24 hours in a dark room atmosphere at 50% RH and 25°C. 175
A printing plate with a predetermined pattern is created using an electronic plate making machine.

(6) Evaluation of the deterioration of image quality due to changes over time was conducted as follows: The obtained printing plate material was placed in a black polyvinyl chloride bag (the bag was sealed, and the bag was kept at a temperature of 35°C for 1 month). The photoconductive layer was pre-exposed to 1000 lux for 10 seconds, and the charging characteristics of the photoconductive layer were measured using EPA (manufactured by Kawaguchi Electric).
This printing plate material was molded into an Eri printing plate using an Itic 175 plate making machine, and the pre-exposure properties of the printing plate material before and after the time change test before t0 were compared based on the E P A ll J list price. Shown in the table.

(η) The printing test of the obtained printing plate was carried out by first desensitizing the printing plate with an etching liquid (manufactured by AITIC Co., Ltd.), using an offset printing machine (Hamada Star 500), and using New Champion F as the ink. A printing durability test (picking evaluation) was conducted using gloss (black) and the results are shown in Table 1.

Comparative Example 1 The same operation as in Example 1 was carried out. However, the intermediate layer paint has the following composition.

-
40 parts by weight polyurethane aqueous dispersion 40
Table 1 shows the results of the pre-exposure and printing durability tests.

Comparative Example 2 The same operation as in Example 1 was carried out. However, the composition of the intermediate layer paint is as follows.
j parts by weight aqueous polyurethane dispersion 40 parts by weight aqueous casein solution 10 1 melamine
Formaldehyde resin (-I80 I-ELS... Trademark: 5R-6t3, manufactured by Sumitomo Chemical) The results of the pre-exposure and printing durability tests are shown in Table 1.

It is clear from Table 1 below that the silane coupling agent contained in the intermediate layer (Example 1) shows almost no change in pre-exposure properties over time and is resistant. The printability was also the best.Compared to the one using glyoxal instead of the silane coupling agent (Comparative Example 1), the time-dependent change in pre-exposure properties was the greatest, and the printing durability was unsatisfactory. A product using a descendant of melamine formaldehyde resin instead of a silane coupling agent (
Comparative Example 2) (; Changes in pre-exposure properties over time were observed, and printing durability (; poorest.

Effects of the Invention In the present invention, by incorporating a silane coupling agent into the intermediate layer, the water resistance and solvent resistance of the intermediate layer are improved, and the aging of the resulting printing plate material is improved. It is possible to prevent image quality from deteriorating due to stains and significantly improve the printing durability of printing plates.

Claims (1)

[Scope of Claims] 1. A support, a photoconductive layer containing a photoconductive pigment and an insulating binder, and an intermediate layer formed between the support and the photoconductive layer; An electrophotographic lithographic printing plate material, wherein the intermediate layer contains a silane coupling agent. 2. The silane coupling agent has the following general formula (I):
RnSiX_4_-_n(I) [However, in the above formula, R represents one member selected from aliphatic, cycloaliphatic, aromatic, and heterocyclic organic substituents having 1 to 30 carbon atoms, and in the above R At least one of the organic substituents represented is a chemically active group, n represents an integer of 1 or 2, and X represents a hydrolyzable substituent.] At least one of the organic silane compounds represented by The material according to claim 1, which consists of seeds. 3. In the general formula (I), the chemically active group represented by R is a vinyl group, a glycidyl group, a mercapto group, an amino group, an epoxy group, a halogen atom, an ester group, and the above groups or atoms. 3. A material according to claim 2, selected from substituted alkyl groups comprising: 4. In the general formula (I), the hydrolyzable substituent represented by X is selected from a halogen atom, an amino group, a hydroxy group, and an alkoxy group having 1 to 4 carbon atoms. Materials described in Section 2. 5. The material according to claim 1, wherein the content of the silane coupling agent in the intermediate layer is 1 to 15% by weight. 6. The material according to claim 1, wherein the weight of the intermediate layer is within the range of 5 to 15 g/m^2.