JPS59198460A - Lithographic plate requiring no dampening water - Google Patents

Abstract

PURPOSE:To improve coating film characteristics, coating performance, etc. by using polyalkylene glycol as a polymer for the binder of a photosensitive layer. CONSTITUTION:A lithographic plate requiring no dampening water is obtained by laminating a photosensitive layer contg. quinonediazide and, as a binder, polyalkylene glycol or its deriv. having 50,000-4,000,000 average mol.wt., and a silicone rubber layer on a support in this order. Polyalkylene glycol is contained in an amt. of 1-91pts.wt. per 100pts.wt. photosensitive layer, and in an amt. of 1-1,000pts.wt. per 100pts.wt. quinonediazide. It is exemplified by a dimer or trimer of ethylene or propylene glycol, and their derivs. are said compds. blocked in one of the terminal or both with ester, alkyl ether, aryl ether, urethane bond, etc.

Description

[Detailed Description of the Invention] Technical Field> The present invention relates to a lithographic printing plate that does not require dampening water, and particularly relates to a lithographic printing plate that does not require dampening water and has a photosensitive layer that has excellent coating properties and coatability. 1. <Prior art> Quinonediazide compounds have traditionally been one of the most widely used photosensitive materials due to their high photoreactivity.
It is widely known that a quinone diazide compound is used in the photosensitive layer even in a lithographic printing plate that does not require dampening water and has a silicone rubber layer.

For example, in the example disclosed in Japanese Patent Application Laid-Open No. 55-59466', it was ladled onto an aluminum plate. A lithographic printing plate that does not require dampening water has been proposed, in which a silicone rubber layer is provided via an adhesive layer on a photosolizable photosensitive layer made of a quinonediazide compound. Furthermore, in an example disclosed in JP-A No. 55-110249, a dampening water-free lithographic printing method is employed in which a silicone rubber layer containing an adhesive component is provided on a photosolubilizing photosensitive layer made of a quinonediazide compound backed by an aluminum plate. A version has been proposed. Furthermore, in an example disclosed in JP-A-56-80046, a partial ester compound of naphthoquinone-1,2-diazide-5-sulfonic acid chloride and phenol novolac (01 fat) is cross-linked with a polyfunctional isocyanate on a photosensitive layer. A lithographic printing plate for negative working that does not require dampening water and has a silicone rubber layer has been proposed.

These lithographic printing plates that do not require dampening water use a quinonediazide compound as a photosensitive substance, so their image forming ability is superior to conventional ones9. Even fine halftone dot sizes can be reproduced. however.

It has been revealed that the following problems exist in the manufacturing, plate making and printing processes of these printing plates.

(1) In printing plates where the image area is a photosensitive layer, the photosensitive layer is hard and brittle, so the photosensitive layer is worn out during printing, and the support is partially exposed in the image area of the printing plate. . This causes unevenness in ink receptivity in the image area, which is then directly transferred to the printed matter, resulting in uneven ink density on the printed matter.

(2) Abrasion damage to the photosensitive layer progresses during printing even in the non-image areas, that is, in the photosensitive layer where the silicone rubber layer remains, and as a result of this, the silicone rubber layer is also abrasion damaged, so the surface of the silicone rubber layer may be partially damaged. The paper tends to pick up ink, resulting in smeared prints and other problems that reduce the quality of printed materials. These mainly have problems with the printing durability of the printing plate.

It seems that.

(3) Known quinone diazide compounds used as photosensitive materials have relatively low molecular weights, and as a result, many pinholes are generated in the photosensitive layer when the photosensitive layer is applied in the form of a thin film. It appears as a defect.

(4) The quinonediazide compound has a low molecular weight and is used to soften rigidity due to the swelling and shrinkage of the support when coating a photosensitive layer on a flexible support that has rubber elasticity, or when handling printing plate precursors and printing plates. Wrinkles and cracks occur in the photosensitive layer due to expansion and contraction of the photosensitive layer due to bending and tension, which not only causes a decline in printing quality but also gives a negative impression on the appearance, reducing the value of the product. .

(5) During the production of printing plate precursors because the photosensitive layer is fragile.

The abrasion resistance of the photosensitive layer is poor, such as the photosensitive layer being easily scratched during development or handling of the printing plate.

(6) Adhesion between the support and the photosensitive layer is insufficient.

<Purpose of the invention> The object of the present invention is to overcome the drawbacks of the prior art mentioned above.

An object of the present invention is to provide a lithographic printing plate that does not require dampening water and has a photosensitive layer with excellent coating properties and coating properties.

<Structure of the Invention> The present invention provides a lithographic printing plate that does not require dampening water and is composed of a support, a photosensitive layer containing a quinonediazide compound, and a silicone rubber layer in this order. The polymer is at least one compound selected from polyalkylene glycols and derivatives thereof.

This is a lithographic printing plate that does not require dampening water, and is characterized in that it contains -1iiH parts of heavy-duty water.

Polyalkylene glycol and its derivatives are used as binder polymers in the present invention.

Good compatibility with quinonediazide compounds and flexibility 2
Those with toughness are selected.

A specific example is polyethylene glycol.

Polymers of alkylene oxides having 2 to 3 carbon atoms such as polypropylene glycol, and derivatives thereof include acetic acid; propionic acid; butanoic acid; benzoic acid; fumaric acid; maleic acid; ester of sodium phthalate, methyl; ethyl: Examples include alkyl ethers such as propyl:cyclohexyl, aryl ethers such as phenyl, urethane bonds such as methyl; ethyl; phenyl: cyclohexane isocyanate, etc., in which one or both ends are blocked.

Such polyalkylene glycols and derivatives thereof preferably have an average molecular weight of tens of thousands to several 60,000. Polyalkylene glycols having an average molecular weight of several thousand or less are not preferred because the effects of the present invention are not significant.

Preferred polyalkylene glycols in the present invention include 2 commercially available polyalkylene glycols, such as Paalcox-30, E
-45,E-60,E-75,E-100,E-1
30, B-160” (Meiji JjM Chemistry).

These polyalkylene glycols and their derivatives as binder polymers are added in an amount of 0.01 to 10 times the weight of the quinonediazide compound, preferably 0.01 to 5 times the weight of the quinonediazide compound.

If the amount added is too small, the effect of the addition will be small, and if the amount added is too large, for example, the photosensitive characteristics of the printing plate will deteriorate, so the amount added needs to be within the above range.

Examples of the quinone diazide compound used in the photosensitive layer of the present invention include quinone diatoes commonly used in positive Ps plates, Wibon plates, photoresists, etc., such as benzoquinone-1,2-diazide-4-Suntake-5-
Esters of sulfonic acid and polyhydroxyphenyl, esters of naphthoquinone-1°2-diazide-4-5-sulfonic acid and pyrogallolacetone resin, naphthoquinone-1,2-diazide-4- or -5-sulfone Examples include esters of acid tophenol formaldehyde with novolak resins, and reaction products of quinone diazides and polyfunctional compounds as proposed in JP-A-56-80046.

Particularly preferred as the photosensitive layer in the present invention is a partial ester compound of naphthoquinone-1,2-diazide-5-sulfonic acid and phenol formaldehyde novolac resin, in which a binder polymer selected from polyalkylene glycols and derivatives thereof is added. This is what I did.

In addition, other components may be added to the photosensitive layer of the present invention for the purpose of improving coating film forming properties and adhesion to the support within a range that does not impair the effects of the present invention.

Alternatively, it is also possible to add a dye or the like to make the image visible during development or exposure.

The composition for forming the above-mentioned photosensitive layer is a suitable organic solvent (for example, dioxane, tetrahydrofuran, cellosolve, cellosolve acetate-1.

DMF, etc.).

The thickness of the photosensitive layer is 01-100μ, more preferably 05-100μ.
60μ is selected. If it is too thin, pinholes are likely to occur in the photosensitive layer, while if it is too thick, it is economically disadvantageous, so the above range is preferable.

The silicone rubber layer used in the present invention usually has as its main component a linear organic polysiloxane having a molecular weight of several thousand to several hundred thousand and having a silicone unit as shown below.

Here, n is an integer of 2 or more, R is an alkyl group, alkenyl group, or phenyl group having 1 to 10 carbon atoms, and R is 6
The strict criteria are those in which 0% or more are methyl groups. Such a linear organic polysiloxane is sparsely crosslinked to form a silicone rubber.

Instead, a crosslinking agent is added to the linear organopolysiloxane.

Examples of crosslinking agents include acetoxysilane, ketoximesilane, alkoxysilane, aminosilane, amidosilane, etc., which are used in so-called room temperature (low temperature) curing silicone rubber. In combination with the deacetic acid type,
De-oxime type.

It becomes dealcoholized, deamined, and deamidated silicone rubber. These silicone rubber layers.

Furthermore, a small amount of an organic tin compound or the like is generally added as a catalyst.

The appropriate thickness of the silicone rubber layer is about 0.5 - 100μ, preferably about 0.5 - 0.0μ. If it is too thin, problems may occur in terms of printing durability and ink repulsion.
On the other hand, if it is too thick, it is not only economically disadvantageous, but also
The silicone rubber layer is difficult to remove during development, resulting in a decrease in image reproducibility.

In the lithographic printing plate that does not require dampening water of the present invention, adhesion between the support and the photosensitive layer, and between the photosensitive layer and the silicone rubber layer is very important for basic plate performance such as image reproducibility and printing durability. If necessary, an adhesive layer may be provided between each layer, or an adhesive component may be added to each layer. In particular, for adhesion between the photosensitive layer and the silicone rubber layer, a known silicone primer, silane coupling agent, or titanate coupling agent layer may be provided between the two layers, or a silicone primer, silane coupling agent, or titanate coupling agent layer may be provided between the silicone rubber layer or the photosensitive layer. It is effective to add a titanate coupling agent.

As a support, it must be flexible enough to be installed in a normal lithographic printing machine, and must be able to withstand the stress that is applied during printing. Typical examples include (d aluminum Uno, +
f Same, gold k of zinc, steel, etc.]6
Koblen rubber, blBR like h rubber elasticity f]p
l N body, a rubber elastic layer 4 I′j 9
4 #, l, body, mogu lr) coated paper, etc. This substance can be used as a support by coating it with a coating for other purposes. is also possible.

(hereinafter) the silicone rubber layer forming the surface of the dampening water-free lithographic printing plate prepared as described above.
For the purpose of protection, the surface of the silicone rubber layer is treated with a blank or uneven surface;
The protective layer can also be formed by coating or transferring a sheet or a thin plastic sheet.

The lithographic printing plate which does not require dampening water and is based on the present invention can be manufactured, for example, as follows. 1'-1/CH'/ of the support
Bath roll coater, air knife coke.

A regular coater such as a Meyer bar coater, or a rotating 4-cloth device like a Whaler? After applying a composition solution to form the photosensitive layer using
If necessary, apply an adhesive layer on the photosensitive layer in the same manner as above, and after drying, apply a silicone gum solution over the photosensitive layer or on the adhesive layer in the same manner.
~1~0°C vortex for a few minutes! I tai netsujo J [l!
The silicone rubber layer is then sufficiently cured to form a silicone rubber layer. If necessary, apply a protective layer or cover the silicone bottle layer with a protective film using a laminator or the like.

Manufactured in this way, no dampening water is required according to the present invention 31/
- Plate The printing plate can be exposed to actinic radiation through two eg vacuum-bonded negative or positive films. The light source used in this exposure step is one that generates α-rich ultraviolet rays, and can be a mercury lamp, a carbon arc lamp, a xenon lamp, a metal halide lamp, a tungsten lamp, a fluorescent lamp, or the like.

Next, when the printing plate is rubbed with a developing pad containing a developing solution, at least the silicone rubber layer in the image (3) area is removed.
A printing plate is obtained in which the exposed surface of the photosensitive layer or support serves as an ink-receiving surface.

The developing solution used in the present invention includes aliphatic hydrocarbons (hexane, ganolin, kerosene, etc.) and aromatic hydrocarbons (toluene, etc.).

The following polar solvents or polar solvents and water added to halogenated hydrocarbons (such as tricrene, etc.) are suitable.

Alcohols (methanol, ethanol, etc.) Ethers (dioxane, etc.) Cellosolves (ethyl cellosolve, methyl cellosolve,
butyl cellosolve, etc.) carpitols (methylcarpitol, ethyl carpitol, butyl carpitol, etc.) esters (ethyl acetate, ethyl cellosolve acedate, methylseron rub acetate, carpitol acetate, etc.).

The thus obtained lithographic printing plate which does not require dampening water of the present invention has the following features.

(1) The printing durability of the printing plate is significantly improved by adding polyalkylene glycol and its derivatives as a binder polymer. For example, if the photosensitive layer is made only of a quinonediazide compound, or if the quinonediazide compound is crosslinked with a low molecular weight crosslinking agent, the photosensitive layer will be hard and brittle, so it will absorb the impact caused by the contact between the printing plate of the second plate cylinder and the blanket cylinder during printing. Failure to do so may result in abrasion damage to the printing plate. However, when polyalkylene glycol and its derivatives are added as a binder polymer, this impact is absorbed by the binder polymer, so that the abrasion resistance of the photosensitive layer is significantly improved. Therefore, damage to the silicone rubber layer due to uneven ink receptivity in the photosensitive layer in the second image area or damage to the photosensitive layer in the non-image area is eliminated, resulting in an improvement in the printing durability of the printing plate.

(2) When developing a printing plate in which only the silicone rubber layer in the image area is removed and the photosensitive layer remains, when polyalkylene glycol and its derivatives are added as a binder polymer, it is more effective than simply crosslinking the photosensitive layer with a crosslinking agent. This improves the solvent resistance of the photosensitive layer, such as allowing the photosensitive layer to remain more reliably without being removed during production.

(3) Coatability of the photosensitive layer is improved.

Quinonediazide compounds generally have a relatively low molecular weight;
For this reason, when coating in a thin film, the coating tends to have drawbacks such as pinholes, but the addition of polyalkylene glycol and its derivatives improves the coating forming properties of the composition that forms the photosensitive layer. Therefore, a photosensitive layer without defects such as pinholes can be obtained.

(4) By adding polyalkylene glycol and its derivatives as a binder polymer to the photosensitive layer, flexibility is imparted to the photosensitive layer, and the occurrence of cracks, etc. in the printing plate precursor and printing plate is significantly reduced.

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

Example 1 (A) The following photosensitive layer composition was spin-coated on a chemically treated aluminum plate (thickness θ6 sam) manufactured by Sumikata Light Metal Co., Ltd.
Heat treatment was performed for 1 minute to form a photosensitive layer with a thickness of 20 μm.

a) Naphthoquinone-1,2-diazide-5-sulfonic acid ester (naphthoquinone-1,2-diazide-5-
Condensation product of sulfonyl chloride and phenol formaldehyde novolac resin) (molecular weight approximately 2000,)i
oo parts by weight b) Polyethylene glycol (Alcox E45
(Kisei Kagaku), average molecular weight 600,000 to 800,000) 20 molar parts c) 4.4'-diphenylmethane diinocyana-1.2
0 parts by weight d) Diptyltin dilaurate 02 parts by weight e) Dioxane 2,000,000 parts by weight After spin-coating a silicone rubber layer composition having the following composition 12
Heat cured at 0°C for 2 minutes at a dew point of 30' to a thickness of 22μ.
A silicone rubber layer was provided.

a) Dinotylborisiloxane (molecular weight approximately 80,000° terminal hydroxyl group) 100 parts by weight b)
Vinyltos(methyl ethyl ketoxime), 7
8 parts by weightC) Dibutyltin diacetate 02 parts by weightd) γ-[:N-(β-aminoethyl)amine]propylmethoxysilane 10 parts by weighte) "'Impar E" (manufactured by Exxon Chemical, aliphatic hydrocarbon 1800 parts by weight of the printing plate precursor obtained as described above was passed through a negative film with a 15 [0 line halftone image] in vacuum contact with a Mekulno Ride lamp (Iwasaki Electric Paddle Fin 2000"). The plate was exposed for 60 seconds from a distance of 1 m using a dye (Oi).
A developing solution (Blue A) containing a developer (Blue A)
(manufactured by Exxon Chemical, aliphatic hydrocarbon solvent)/ethanol-8/2) K immersion and rubbing lightly with a developing pad removes only the exposed silicone rubber layer, faithfully reproducing the negative film image. A printing plate was obtained in which the exposed photosensitive layer was partially dyed.

(B) For comparison, a photosensitive layer with the following composition was provided on an aluminum plate similar to the above to a thickness of 20μ, and heated at 120°C.
The sample was heat-treated for 1 minute.

a) Phenol novolac resin with a degree of esterification of 44 (
``Sumilight Resin PR50235''.

Naphthoquinone-1,2-diazide (manufactured by Sumitomo Durez)
5-sulfonic acid ester (molecular weight approximately 2000)
100 parts by weight b) 20 parts by weight of 4,4'-diphenylmethane diisocyanate C) Dibutyltin dilaure-1.02 parts by weight d)
Dioxane 2 (100 parts by weight) Subsequently, the same silicone rubber layer as in (A) was provided thereon to the same thickness and heat treated at 120° C.2 dew point 30' for 2 minutes.

This was exposed and developed in the same manner as in (A), and then
- A printing plate similar to (A) in which only the cone rubber layer was removed was obtained.

The printing plates obtained in (A) and (B) were each attached to an offset printing machine (Failure Sprint 2 Color) and printed using Aquares Ai ST (manufactured by Toyo Ink) without using dampening water.

In (B), after 10,000 sheets were printed, damage was observed in the image area of the printing plate, and damage was also observed in the silicone rubber layer, which is a non-image area, due to damage to the underlying photosensitive layer. Correspondingly, marks such as uneven printing due to damage to the photosensitive layer were observed in the image area of the printed matter, and stains due to ink sticking were observed in the non-image area.

On the other hand, in the printing plate obtained in (A), even after printing 60,000 copies, no damage was observed in the image area or non-image area of the printing plate11, and the printed matter was free from defects.

In this printing plate precursor, the number of pinholes in the photosensitive layer was counted, and the diameter was measured using a magnifying glass (×100) with a scale. The results were as shown in Table 1, "Pinhole V per m2".

Table 1 Example 2 (A) The following photosensitive layer composition was spin-coated on a 0.3 mm thick chloro-'prene rubber layer [rubber hardness 60 (Shore A)], and then heated at 60°C for 215 minutes. A photosensitive layer having a thickness of 2 μm was provided.

a) Phenolic novolak resin with a degree of esterification of 44% ('Pasumilite Resin R50265'').

Naphthoquinone-1,2-diazide (manufactured by Sumitomo Durez)
5-sulfonic acid ester (molecular weight approximately 2000)
100 parts by weight b) Polyethylene glycol (Alcox E100 (Kaisei Kagaku), average molecular weight 2.5 to 3 million) 20
Part by weight C) Dioxane 2000 parts by weight The photosensitive layer obtained had a smooth surface without cracks.

(]3) - Force, same as (A) (on the chloroprene rubber layer of the strip.

A photosensitive layer of i+ of the lower Ae was provided to a thickness of 2 μm.

Heat treated at 60'C for 15 minutes.

a) Phenolic novolak resin with degree of esterification of 4.4 q6 (Pasumilite Resin PR50235").

Naphthoquinone-1,2-diazide (manufactured by Chutomo Durez)
5-sulfonic acid ester (molecular weight approximately 2000)
100 parts by weight b) Dioxane
2000 parts by weight A) The leaked photosensitive layer was visually observed to have cracks.

(A) was superior to (B) in terms of resistance to scratching of the photosensitive layer, abrasion resistance λ/L, flexibility of the film, etc.

EXAMPLE A photosensitive layer was applied in the same manner as in Example 1 to which 20 parts each of the following binder polymers were added as component (b) in A of Example 1.

Table 2 shows the results of evaluating the cracks, pinholes, and wear resistance of the photosensitive layer.

Claims (2)

[Claims] (1) One support J", a photosensitive layer containing a hexanondiazide compound and a cone rubber layer in this order -f
? I' made of i-layer! II! In the lithographic printing plate that does not require water, at least one compound selected from polyalkylene glycol and derivatives thereof is contained as a binder polymer in 100 parts by weight of the photosensitive layer in an amount of 1 to 1000i<1.
A lithographic printing plate that does not require dampening water and is characterized by containing IX. (2) The average molecular weight of the pinter polymer is 50,000 to /100
The lithographic printing plate that does not require dampening water according to claim 1, characterized in that the dampening water-free lithographic printing plate is