JPS6046557A - Lithographic original plate requiring no dampening water - Google Patents

Abstract

PURPOSE:To enable a lithographic original plate requiring no dampening water to be processed under a light white lamp by laminating a protective cover capable of cutting a specified proportion or more of a photosensitive wavelength region not above a specified wavelength on the uppermost silicone rubber layer of said plate. CONSTITUTION:A silicone rubber layer is formed as an ink repelling layer on a photosensitive layer made of diazotized novolak resin or the like formed on a base plate, and this rubber layer is coated with a protective cover made of a polymer film, synthetic paper, or the like filled with inorg. pigment, such as ceramic black, TiO2, carbon black, or an org. material, such as UV absorbed or dyes to cut >=60% of <=500nm wavelength lights. When a photosensitive silicone rubber layer is formed on the base plate, said photosensitive layer is unnecessary, and this photosensitive rubber layer is coated with said protective cover. As a result, the obtained lithographic original plate requiring no dampening water can be processed under a light white lamp and stored and handled easily.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a lithographic printing original plate that does not require dampening water and is characterized by using a protective cover that cuts the photosensitive wavelength range.

[Prior art]

Conventionally, various types of lithographic printing plates that do not require dampening water have been known that use a silicone rubber layer as an ink-repellent layer.
Among them, several lithographic printing plates that do not require dampening water have been proposed in the past, which are formed by providing a silicone rubber layer on a photosensitive layer backed by a support.

For example, as a negative-working plate material, one in which a silicone rubber layer is provided on a photoreleasable photosensitive layer provided on a support and presensitized is proposed in JP-A-56-80046. . Further, JP-A-55-110249 proposes a lithographic printing plate in which a silicone rubber layer containing aminosilane is provided on a photoreleasable photosensitive layer backed by a support.

Furthermore, USP-3677 is a plate material that works on positive type.
No. 18 proposes a lithographic printing plate in which a silicone rubber layer is provided on a photocurable diazo photosensitive layer backed by an aluminum plate.

In such printing plates, it is common to provide a protective film on the silicone rubber layer.

When printing plates are handled in a dark room with white light, they are exposed to light.

becomes unusable. Therefore, like the PS version, it must be handled under yellow fluorescent light or anti-fading light.

[Purpose of the invention]

To obtain a lithographic printing original plate that does not require dampening water and has good bright room stability and can be handled even under white light.

[Structure of the invention]

The present invention is a lithographic printing original plate that does not require dampening water and has a silicone rubber layer as the outermost layer, and is characterized in that a protective cover that cuts 60% or more of light having a wavelength of 5000 A or less is laminated on the silicone rubber layer. This invention relates to a lithographic printing original plate that does not require dampening water.

The protective cover used in the present invention has a wavelength of 5
It can cut 60% or more of light rays of 000A or less, and includes, for example, inorganic pigments (ceramic black, iron oxide, titanium oxide, zinc oxide, etc.), organic pigments (carbon blank, bone black, etc.), ultraviolet absorbers (2- (2/-hydroxy-5
- polyester, polystyrene, polyethylene, polyvinyl chloride, nylon polypropylene mixed with methylphenyl)benzotriazole, 2-hydroxypenzophenone, phenylsalicylate or dyes, etc.
Polycarbonate, cellophane.

Examples include films such as cellulose triacetate, synthetic paper, aluminum coated paper, and film coated paper.

It is very preferable for the above protective cover to block all light rays with a wavelength of 5000X or less, but at least 60%
It is necessary to cut by 80% or more, and it is effective to cut by 80% or more.

There is no particular limit to I'i as the thickness of the protective cover.

For handling purposes, the thickness is 1 to 300μ, more preferably 6 to 150μ.

The present invention is applied to a planographic printing original plate that does not require dampening water.

It may have a photosensitive silicone rubber layer lined to the substrate, or it may have a known photosensitive layer lined to the substrate via an adhesive layer if necessary under the silicone rubber layer. good.

Below are the substrates constituting the above-mentioned dampening water-free lithographic printing original plate,
The photosensitive silicone rubber layer, photosensitive layer, and silicone rubber layer will be explained.

As the substrate, paper, plastic film or sort, metal plate, etc. having a thickness of about 10 .mu.m to 2 mm, preferably about 50 .mu.m to 500 .mu.m are suitable.

A substrate having rubber elasticity or a cylindrical substrate may also be used.

Photosensitive silicone rubber layer The silicone rubber layer itself is photosensitive, and in this case, no photosensitive layer is required. As the photosensitive silicone rubber, γ-methacryloxypropyltrimethoxysilane is used as the terminal OH group of dimethylpolysiloxane.

Alternatively, examples include compounds obtained by dealcoholization condensation of monononnamoyldiethoxysilane, compounds obtained by adding a bisazide compound to polydiorganosiloxane, or compounds obtained by reacting acryloyl chloride or p-azidobenzoate.

Further, a known photosensitive substance may be mixed with silicone rubber and used as a photosensitive silicone rubber layer.

The photosensitive layer is a layer that has the property of being photocured or photosolubilized by irradiation with active light. Although its thickness is arbitrary, it is preferably about 100 microns or less, more preferably about 05 to 10 microns.

As the photosensitive material, one having the following first-order structure is suitable.

(1) Diazo compound Diazo resin such as an aldehyde (such as formaldehyde) condensate of p-diazodiphenylamine.

Diazotized novolak resin, p-diazoquinone, p-iminodiazoquinone, photosensitive composition comprising diazonium salt and polyvinyl alcohol, poly(hydroxyethyl methacrylate) and diazo resin, etc.

(2) Orthoquinonediazides Orthoquinonediazide-based photosensitive substances, photosensitive compositions consisting of orthonaphthoquinonediazide and novolac-type phenolic resin, esters of quinonediazide sulfonic acid and novolak resin, sulfonamides of quinonediazide sulfonic acid and polyaminostyrene. , esters of quinonediazide sulfonic acid and polyhydroxystyrene, quinonediazide sulfonic acid and poly-p-hydroxymethacrylanilide, and the like.

(3) Azides (including sulbonyl azide and carbonyl azide) 4. Mixture of a water-soluble aromatic azide compound such as 4/-diazidostilbene-2,2/-disulfonic acid and a copolymerizable polymer of acrylamide or acrylic monomer ,2,6-
A mixture of a water-insoluble aromatic azide compound such as di(4'-azidobenzal)-4-methylnoroxane or 4,4/-diazidobenzophenone and polyvinylpyrrolidone or a copolymer thereof, polyvinyl-p-azidobenzoate, etc. Polyvinyl-p-azidobenzal acetalized with p-azidobenzaldehyde, etc.

(4) A complex of a diazo compound and an inorganic or organic acid; a photosensitive complex of diazodiphenylamine and phosphotungstic acid; and the like.

(5) A mixture of polyfunctional monomers, oligomers, etc. having two or more unsaturated groups in one molecule with a suitable polymer binder.

Typical photopolymerizable unsaturated groups include a, acryloyl group, methacryloyl group, and acrylamide group.

maleate ester group, allyl group, vinyl ether group,
Vinylthioether group, vinylamino group.

Examples include glycidyl groups and acetylenically unsaturated groups.

(6) Photosensitive polymers obtained by pedanting photosensitive groups to existing polymers, or modified versions thereof.

A typical photosensitive group is an olefin group.

Cinnamoyl group, cinnamylideneacetyl group, Fe=
/I/ 7 Mr ``Aso group, α-phenylmaleimide group, and the like.

The silicone rubber layer used in the present invention is usually about 0.5
The main component is a linear organopolysiloxane having a thickness of ~100μ, preferably about 0.5~60μ, and a molecular weight of several thousand to several dozen blades and having a repeating unit such as the first order.

(Here, n is an integer of 2 or more, R is an alkyl group, alknyl group, or aryl group having 1 to 10 carbon atoms, and R
(Preferably, 60% or more of the methyl groups are methyl groups.) This linear organopolysiloxane usually contains a crosslinking agent.

A catalyst etc. are added.

Examples of crosslinking agents include acetoxysilane.

Ketooxysilane, alkoxysilane, aminosilane, etc. are used, and as the catalyst, for example, an organic tin compound etc. are used.

The thickness of the silicone rubber layer is preferably 05 to 20 microns. In addition, if necessary, a known silicone primer or silicone coupling agent layer may be provided between the silicone rubber layer and the photosensitive layer or between the silicone rubber layer or the photosensitive layer for adhesion between the silicone rubber layer or the photosensitive layer and the substrate. It is also effective to add a known silicone primer or silane coupling agent.

Next, the steps of the method for manufacturing a lithographic printing original plate that does not require dampening water according to the present invention will be explained.

First, a composition solution to form a photosensitive layer is applied onto the substrate using a conventional coater such as a reverse roll coater, an air knife coater, or a rotary coating device such as Boera, followed by drying and heat curing if necessary. , a silicone gum solution is applied on the photosensitive layer in the same manner as 2, usually 100 to 1
Heat treatment is performed at a temperature of 20° C. for several minutes to fully cure and form a silicone rubber layer.

Next, as a protective layer, light rays with a wavelength of 5000A or less are
A lithographic printing original plate that does not require dampening water can be obtained by laminating a protective cover that is cut more than one inch onto the silicone rubber layer using a laminator or the like.

The thus obtained lithographic printing original plate that does not require dampening water is exposed to actinic rays through an original film that is vacuum-adhered after the protective cover is peeled off. After exposure.

A printing plate is obtained by developing with a known developer for a lithographic printing plate that does not require dampening water.

〔Effect of the invention〕

According to the lithographic printing original plate that does not require dampening water according to the present invention, the following effects can be achieved.

(1) Even if the original printing plate is left under a bright room light, the original printing plate will not become unusable because it will not be exposed to active rays.

(2) Work efficiency is improved because printing original plate cutting and packaging operations can be performed in a bright room during the manufacturing process.

(3) Effective in preventing foreign matter such as dust from adhering to printing plates.

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

Examples 1 to 4 Comparative Examples 1 and 2 The following photosensitive layer composition was spin coated on a chemically treated aluminum plate (manufactured by Sumitomo Light Metals, thickness 0.24-), and heated at 120°C for 2 minutes to give a thickness of 2. .2 micron photosensitive layer was provided.

(a) 100 parts of naphthoquinone-1,2-diazide-5-sulfonic acid ester of phenol novolac resin (Sumilight Resin pR5023, 5, manufactured by Sumitomo Durez) with a degree of esterification of 44% (b) 4*''-diphenylmethane diisocyanate Natoro 0 parts (C) Paratoluenesulfone (d) Dibutyltin diacetate 02 parts (θ) Tetrahydrofuran 2,000 parts Then, after spin-coating the silicone rubber composition below, heat it at 120°C for 3 minutes. A silicone rubber layer with a thickness of 2.6 μm was provided by hardening.

(a) Dimethylpolysiloxane 100 parts (molecular weight approximately so, ooo terminal hydroxyl group) (b) Vinyltrimethylethylketo 8 parts oximesilane (C) dibutyltin diacetate) 0. 2 parts (d
) 2 parts of γ-aminopropyl trimeto Xysilane (θ) 1 part of Aitunony E Furthermore, a protective cover shown in Table 1 was laminated onto this silicone rubber layer using a laminator to prepare a lithographic printing original plate that did not require dampening water.

The dampening water unnecessary child n anti-seal notification 11 original plate obtained as described above was left at a distance of 1.5 m under a white light, and the allowable exposure time was examined. The permissible exposure time is defined as the time at which the range of change in gray scale sensitivity due to the presence or absence of light exposure is 2 or less when the gray scale sensitivity is evaluated using a developer.

When no actinic rays are transmitted at all as in Example 1, the allowable exposure time is significantly improved. Moreover, Examples 2 to 4
Although the allowable exposure time became shorter as the cut rate for wavelengths of 5000X or less became smaller, it is judged that the protective cover has practical utility.

On the other hand, in the comparative example of polypropylene or without a protective cover, the allowable exposure time was very short, 3 to 5 minutes.

Example 5 Comparative Example 3 A resol resin (Sumilight Resin PC-1: manufactured by Sumitomo Durez) was applied to a thickness of 1μ on an aluminum plate (manufactured by Sumitomo Light Metal) with a thickness of 0.24 mm, and cured at 180r for 6 minutes. It was used as a substrate. This substrate was coated with a 7-enol novolac resin with a degree of esterification of 44% (Sumiresin PR manufactured by Jumyu Durez).
50235) naphthoquinone-1,2-,,>azide-
A 6-weight dioxane solution of 5-sulfonic acid ester (ethanol-soluble component: 97% by weight, degree of esterification determined from IR spectrum) was spin-coated with a wheal and dried.
A photosensitive layer of μ was formed. A silicone rubber layer having a thickness of 25 μm was provided by spin-coating the following composition on top of this and curing it by heating at 12 DC for 4 minutes.

(a) Dimethylpolysiloxane 100 parts (molecular weight approximately 30,000, terminal OH group) (b) Methyltriacetoxysilane 6 parts (C) Dibutylstin diacetate
02 parts (d) 35 parts of γ-aminopropyl triethate 1500 parts of Quinane (θ) Isopar E Next, Lumirror (50μ) mixed with carbon black used in Example 1 was laminated on this silicone rubber layer using a laminator. A lithographic printing original plate that does not require dampening water was created.

The lithographic printing original plate that does not require dampening water obtained as described above was left in a bright room for several days, and then the Lumirror was removed and 150 lines/
The film was irradiated for 60 seconds from a distance of 1 m using a metal halide lamp (Idolfin 2000, manufactured by Iwasaki Electric) through a negative film having a halftone dot image of 1.5 inches. This exposed printing plate was then treated with ethanol/isopar E (6
5/35 weight ratio).

On the other hand, the exposed area is easily removed to expose the substrate.

The silicone rubber layer remained firmly in the unexposed areas, and a printing original plate with an image that faithfully reproduced the negative film was obtained.

On the other hand, as a comparative example, a lithographic printing original plate that does not require dampening water was left in a bright room for 10 minutes with the protective cover removed.

When exposed and developed as shown above, even the silicone layer 9, which should originally be a non-image area, was removed.

It was not possible to obtain a printed version.

Patent applicant Higashi Shikikai Co., Ltd.

Claims (1)

[Claims] In a lithographic printing original plate that does not require dampening water and has a silicone rubber layer as the uppermost layer, the silicone rubber layer has a wavelength of 5000 nm.
A lithographic printing original plate that does not require dampening water and is characterized by being laminated with a protective cover that cuts 60% or more of light rays of A or lower.