JPS6374065A - Waterless planographic form plate - Google Patents

Abstract

PURPOSE:To obtain good image reproducibility by incorporating a quinone diazide compd. and polyamide and/or polyurethane contg. an amino group into a photosensitive layer at specific weight. CONSTITUTION:100pts.wt. quinone diazide compd. and 5-1,000pts.wt. polyamide and/or polyurethane contg. the amino group are incorporated into the photosensitive layer of a waterless lithographic printing plate formed by coating the photosensitive layer contg. the quinone diazide compd. and silicone rubber layer in this order on a base. Only the silicone rubber layer in the unexposed part is thereby removed with substantially no decrease in the thickness of the photosensitive layer by the selection of a developing solvent; therefore, the transfer of ink to an ink receiving part at the time of printing is good and the printed matter having a good gradation characteristic is obtd.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a waterless lithographic printing plate.

(Prior Art) Quinonediazide compounds have traditionally been one of the most widely used photosensitive KA materials due to their high photoreactivity.
It is widely known that quinonediazide compounds are used in the photosensitive layer even in waterless lithographic printing plates having a silicone rubber layer.

For example, in the example disclosed in Japanese Patent Publication No. 61-616, a waterless lithographic printing plate is prepared in which a silicone rubber layer is provided via an adhesive layer on a photo-solubilizable photosensitive layer made of a quinone diazide compound, which is lined with an aluminum plate. Proposed. In addition, an example disclosed in JP-A-55110249 proposes a waterless lithographic printing plate in which a silicone rubber layer containing an adhesive component is provided on a photo-solubilizable photosensitive layer made of a quinonediazide compound backed by an aluminum plate. has been done. Furthermore, in an example disclosed in JP-A-56-80046, a silicone rubber is coated on a photosensitive layer in which a partial ester compound of naphthoquinone-1,2-diazide-5-sulfonic acid chloride and a phenol novolak resin is crosslinked with a polyfunctional isocyanate. Negative waterless lithographic printing plates with layers have been proposed.

All waterless lithographic printing plates using these quinonediazide compounds are negative type.

Japanese Patent Publication No. 56-6536 discloses that a small amount (115 to 100% of the polymer
A photosensitive resin composition to which quinone diazide No. 11500) is added is disclosed. Unlike the case where quinonediazide is used alone, the unexposed portions of this photosensitive resin composition are removed by development, and an exposed portion resin film image is formed.

By applying the waterless lithographic technique described above to this technique, a positive waterless lithographic plate using quinonediazide can be created using I! It is expected that A construction will be possible. However, contrary to expectations, a practical printing plate could not be obtained. That is, good image reproducibility could not be obtained due to insufficient adhesion between the silicone rubber layer and the photosensitive layer and low sensitivity.

As a result of intensive research into the improvement thereof, the present inventors discovered that a specific photosensitive layer composition can be used as a positive type, and the present invention has been achieved.

[Problem that the invention seeks to solve]

As mentioned above, the object of the present invention is to provide a novel photosensitive layer in which a quinonediazide compound, which has been conventionally used as a photosensitive layer in a negative-working waterless planographic printing plate, is used in a positive-working waterless planographic printing plate. .

[Means for solving problems]

The present invention provides a waterless lithographic printing plate comprising a support, a photosensitive layer containing a quinonediazide compound, and a silicone rubber layer coated in this order, the photosensitive layer comprising (a) 100 parts by weight of a quinonediazide compound, (b) an amino The present invention is a positive-working waterless lithographic printing plate characterized by containing 5 to 1000 parts by weight of a polyamide and/or polyurethane having a polyamide group.

The quinonediazide compounds used in the present invention include quinonediazides normally used in positive PS plates, Wibon plates, photoresists, etc., such as benzoquinone-1,
Esters of 2-diazide-4 or 5-sulfonic acid with polyhydroxylphenyl, phenol-formaldehyde novolak resin, talezol-formaldehyde novolac) anti-fat, quinonediazides and cyisocyanate-1 proposed in JP-A-56-80046. Examples include reactants with polyfunctional compounds such as ~. Particularly preferably used are phenol or cresol-formaldehyde resins into which naphthoquinone-1,2-diazide-5 or 4-sulfonic acid is introduced via an ester bond. Esterification rate with naphthoquinone-1,2-diazide-5 or 4-sulfonic acid is 20% or more, 6
It is preferably 5% or less. Esterification rate is 20%
If it is smaller, there will be less difference in solubility in the developing solvent between the exposed and unexposed areas.

If it exceeds 65%, it will be economically disadvantageous. This Nisdell conversion rate depends on the required performance such as sensitivity, developability, image reproducibility, etc.
It is selectively used in the range of 20% or more and 65% or less.

The polyamide or polyurethane having an amino group used in the present invention has superior compatibility with a quinonediazide compound compared to a vinyl polymer having an amino group.
Even when the amount of quinonediazide compound is increased, it remains transparent! A photosensitive layer can be obtained.

Examples of polyamides having amino groups include -NCC, 12CH, NCHpC, and 2-1 concave polyamides. Examples of polyurethanes having amino groups include polyurethanes containing 111 or burr. used.

In the present invention, as the more preferable polyamide or polyurethane having an amino group, there is used a polyamide or polyurethane having a trivalent amino group consisting of an alkyl group having 1 to 6 carbon atoms.

Mixing of these quinonediazide compounds with polyamide d3 and/or polyurethane containing amino groups^11
Although the amount varies depending on the thickness of the photosensitive layer, printing method, required performance, etc., the former is used in a maximum aperture of 100 parts by weight, whereas the latter is used in a total amount of 5 to 1000 parts by weight. If the amount is less than 5 parts by weight, the function as a positive type will not be fully expressed, and if it is more than 1000 parts by weight, image reproducibility will be poor.

A more preferable range is 10 to 500 parts by weight, and a particularly preferable range is 20 to 300 parts by weight.

As mentioned above, the reason why a waterless lithographic printing plate consisting of a photosensitive layer containing polyamide and/or polyurethane having an amino group and a quinonediazide compound functions as a positive type is still not fully understood, but it is probably because the quinonediazide structure is changed by exposure to light. Decompose to indene carbon MH
This is thought to be because the carboxylic acid forms a bridge through ionic bonding with the amino group in the polymer, resulting in a decrease in swelling or solubility in solvents.

The thickness of the photosensitive layer is preferably selected from 0.1 to 100μ, more preferably from 0.5 to 30μ. If it is too thin, pinballing tends to occur in the photosensitive layer during coating, and if it is too thick, it is undesirable from a practical standpoint.

In addition, other components may be added to the photosensitive layer of the present invention for the purpose of improving coating film formation properties and adhesion to the support, within a range that does not impair the effects of the present invention, or during exposure. Alternatively, it is also possible to add a dye or the like to visualize the image during development.

The thickness of the silicone rubber layer which is the ink repellent layer used in the present invention is preferably 0.5 to 100 microns, more preferably 1 to 50 microns.

A useful silicone rubber is a linear silicone rubber whose main component is polysiloxane, which has the following repeating units, has a molecular weight of several thousand to several hundred thousand.

It is preferable that (R is an alkyl group having 1 to 10 carbon atoms, or) a diyl group, or 60% or more of R is a methyl group. ) This linearity is achieved by using polysiloxanes that usually have terminal hydroxyl groups, such as acetoxysilane, ketoxime silane,
A cross-linking agent such as an alkoxysilane is present, and if necessary, cross-linking is performed by heat treatment in the presence of a catalyst such as a prominent tin compound, and the layer is used as a silicone rubber layer.

In addition, if necessary, a silicone rubber layer and a photosensitive resin layer,
Alternatively, for adhesion between the photosensitive resin layer and the support layer, a known silicone primer or silicone coupling agent layer may be provided in the living room, or a known silicone primer or silicone coupling agent may be applied to the silicone rubber layer or the photosensitive resin layer. It is also effective to add it.

The support must be flexible enough to be set in a normal lithographic printing space and capable of withstanding the load applied during printing. Typical examples include metal plates such as aluminum, steel, and copper, polyethylene terephthalate, Plastic films or sheets such as polyethylene, polypropylene, polystyrene, chloroprene rubber, natural rubber,
Examples include sheets 1 to 1 having rubber elasticity such as butadiene-acrylonitrile rubber and polyetherester elastomer, or metal plates laminated with such rubber elastic layers. It is also possible to coat these supports with other substances for antihalation and other purposes and use them as supports.

Occurrence of scratches on the surface of the silicone rubber layer forming the surface of the waterless lithographic printing plate constructed as explained above.
For the purpose of preventing the adhesion of flakes, the appeal layer may be formed by laminating a plain or textured thin film, or by transferring a thin plastic sheet to the coating film 5.

The waterless lithographic printing plate according to the present invention is manufactured, for example, as follows. First, a photosensitive resin layer is coated on the support using an ordinary coater such as a reverse roll coater, an air knife coater, or a Meyer bar coater, or a rotary coating film 5 device such as Whaler. After coating and drying the composition solution to be formed, if necessary, coat an adhesive layer on the photosensitive resin layer in the same manner and dry. Next, apply the silicone rubber solution on the photosensitive layer or adhesive layer. Apply the same method to
Then, the silicone rubber layer is formed by heating at a temperature of usually 70 to 140°C to sufficiently cure the product. Furthermore, if necessary, a protective layer is coated 5 on the silicone rubber layer or a protective film is laminated using a laminator or the like.

The waterless lithographic printing plate of the present invention thus produced is exposed to ultraviolet rays by vacuum-adhering a positive film having a predetermined pattern, for example.

As a light source that generates ultraviolet rays, a mercury lamp, a carbon arc lamp, a xenon lamp, a metal halide lamp, a fluorescent lamp, etc. can be used. Next, when the plate surface is rubbed with a brush, sponge, pad, etc. for development containing a developer, the silicone rubber layer in the unexposed areas is removed, and the exposed surface of the photosensitive resin layer becomes an ink receiving area. 1 print version
7.

As the phenomenon liquid used in the present invention, a solvent that swells or dissolves the unexposed portions of the photosensitive layer is used. Particularly preferably used organic solvents are those in which the polyamide or polyurethane having an amino group is completely soluble or insoluble, and which dissolves only the quinonediazide compound. When such an organic solvent is used, the photosensitive layer in the unexposed area remains on the support without substantially reducing its thickness, and only the silicone rubber layer is removed, resulting in improved ink receptivity, etc. There is an effect. Examples of the organic solvent used as the developer include ethanol, ethyl cellosolve, dioxane, acetone, methyl ethyl ketone, and ethyl acetate. Hydrocarbons such as hexane, heptane, gasoline, i~luene, and xylene may be mixed with these to adjust the solubility, or to swell the silicone rubber layer and improve penetration of the developer. Good.

(Effects of the Invention) The positive waterless lithographic printing plate of the present invention obtained in this manner must have the following effects.

(1) By selecting the developing solvent as described above, only the silicone rubber layer in the unexposed area can be removed without substantially reducing the thickness of the photosensitive layer, so that ink does not reach the ink receiving area during printing. Printed matter with good transfer and good gradation can be obtained.

(2) Since the polyamide and/or polyurethane having amino groups remains in the image area, staining and inspection is easy.

(3) Since the photosensitive layer contains polyamide/or polyurethane having amino groups, it absorbs forces such as impact, friction, and shearing during printing, and the photosensitive layer in the image area and silicone rubber in the non-image area This reduces layer damage and improves the printing durability of the printing plate.

(4) Quinonediazide compounds generally have a relatively low molecular weight and have drawbacks such as easy formation of pinholes when applied to thin films. However, in the present invention, the photosensitive layer is made of polyamide and/or Contains polyurethane, which improves coating film formation properties and eliminates defects such as pinholes.

The present invention will be explained in more detail with reference to Examples below.
The embodiments of the present invention are not limited to this.

Example 1 Phenol novolac (kali fat) with esterification rate of 46%
Sumilite Resin PR50235, Sumitomo Durez'JA
) ~ 100 parts by weight of quinone-1,2-diazide-5-sulfonic acid ester, poly 2-(N,N'-dimethylamino)caprolactam (manufactured by AQ Nylon Toshi) 15
0 parts by weight was dissolved in ethyl cellosolve so that the total solid content was 15% by weight, and the solution was coated on a 0.3 mm thick chemically treated aluminum plate (Sumitomo Light Metal Equipment Co., Ltd.) using a Meyer bar coater #10. It was dried for 1 minute at c. to form a 2.6 μm photosensitive layer.

On top of this, a 25% Isoperpa E (manufactured by Esso) solution of a silicone rubber composition having the following composition was coated with a Mea A7 bar coater #8, and then heated and cured at 110°C for 4 minutes. , a silicone rubber layer with a thickness of 2.4 μm was obtained.

(a) Polydimethylsiloxane (molecular weight approximately 30,000, DW
OHu > 100 iu Part (b) Vinyltri(methylethylketoxime)silane
8 parts (C) 0.1 part by weight of dibutyltin dilaurate (d) 3 parts by weight of γ-aminopropyltriethoxysilane 1.
A positive film having a halftone image of 75 lines was exposed for 60 seconds from a distance of 1 m using a 2KW metahalide scrub. Ethyl ruby 1~-ru/"isopar" E=2
By immersing it in a 0/80 mixed solution and rubbing it lightly with a developing pad (Long Run Carpet, manufactured by Yojima Orimono), the unexposed silicone rubber layer is removed and a printing plate that is faithful to the positive film with the surface of the photosensitive layer exposed is obtained. It was done. On the other hand, 1 liter of methacrylic
In a known amino group-containing vinyl polymer having -2-N,N-dimethylaminoethyl, the silicone rubber layer peeled off during development, and no image was obtained.

Example 2 1001 ff 1 part of naphthoquinone-1,2-diazide-5-sulfonic acid ester of phenol novolac resin (Sumilight Resin PR50235, manufactured by Sumitomo Durez) with an esterification rate of 43%, 210 N-methyljetanolamide
0 mol% of polyurethane and 100 mol% of hexamethylene diisocyanate.
Polyethylene terephthalate 1 to 0.25 mm thick was dissolved in dimedylformamide to a concentration of 5% by weight.
(Lumirror, manufactured by Toshi) using a Meyer bar coater #10 and dried at 120° C. for 1 minute to form a 2.6 μm photosensitive layer. A silicone rubber layer was provided thereon under the same conditions as in Example 1 and exposed using the same method. Next, the silicone rubber layer in the unexposed areas was removed and the surface of the photosensitive layer was exposed by immersing it in a mixture of ethyl cellosolve/"isopar" (E = 30/70) and rubbing it lightly with the same developing pad as in Example 1. A printing plate faithful to the positive film was obtained.

Claims (1)

[Claims] In a waterless lithographic printing plate formed by coating a photosensitive layer and a silicone rubber layer in this order on a support, the photosensitive layer is (a)
100 parts by weight of a quinonediazide compound, (b) 5 to 10 parts of polyamide and/or polyurethane having an amino group
1. A positive type waterless lithographic printing plate characterized by containing 0.00 weight.