JPH03184049A - Lithographic printing plate and its manufacturing method - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention [Object of the Invention] (Industrial Application Field) The present invention relates to a lithographic printing plate and a method for producing the same, and more specifically, it relates to a lithographic printing plate and a method for producing the same. This relates to the creation of unnecessary lithographic printing plates.

(Conventional technology and problems) In today's printing industry, PS as a printing plate
The plate (Pre-3 sensitized-Plate) is
Although it has received unwavering support, the plate-making work environment remains poor as it requires liquid development after image exposure.
There were problems such as the emitted gas sometimes corroding equipment near the work environment, shortening the life of the equipment, and requiring huge drainage facilities.

Negative PS plates are disclosed in German Patent No. 596,731, US Patent No. 2,729,562, US Patent No. 2,890,115, British Patent No. 859,781, and the like. However, as a printing plate, it has the drawback of being susceptible to dark reactions and not ensuring sufficient storage stability.

Furthermore, a common problem with these positive and negative PS plates is that they use aluminum with a purity of over 99.9% as a support, which makes them extremely expensive per sheet. To address this drawback, some users peel off the resin film on the PS plate once used, perform surface treatment such as anodizing the aluminum again, wipe on a new photosensitive solution, and reuse it as a PS plate. In other words, the work cost was reduced by reviving and reusing a plate that had been used once.

Accordingly, an object of the present invention is to provide a method for manufacturing a lithographic plate at low cost, which does not require development processing.

[Structure of the invention]

(Means for Solving the Problems) The present inventors formed a photosensitive layer on a support, exposed it to nine images, and determined the difference in tackiness during transfer between the exposed and unexposed areas of the photosensitive layer. It has been found that materials in which an image is transferred to an image receptor (plate material), such as an anodized aluminum plate, are useful as lithographic printing plates.

The imaging material that can be used in the present invention essentially consists of a support,
Consists of a photosensitive layer and, if necessary, a protective film.

As a support, it is stable against heat, chemicals, light, etc.

Moreover, a material that sufficiently transmits actinic rays is preferable. For example, cellulose acetate, polystyrene.

Films or sheets made of polyvinyl chloride, polyethylene terephthalate, polypropylene, etc. Particularly preferred is a polyethylene terephthalate film or sheet.

In particular, a polyethylene terephthalate film or sheet is preferred from the viewpoints of transparency, thermal stability, two-dimensional stability, and the like.

As a protective film, polyethylene film is rigid and
It is preferable in terms of oxygen permeability, expansion/contraction rate, surface smoothness, adhesion, releasability, etc.

Further, the transparent support or the protective film may be subjected to conductive treatment in order to remove static electricity generated when the protective film is peeled off.

Examples of materials that can be applied to the photosensitive layer of the image forming material of the present invention include:

(a) Photopolymerizable compound, thermoplastic resin, colorant, (b)
It is composed of a photodegradable compound, a thermoplastic resin, a coloring agent, etc., and additives such as a photopolymerization initiator, a photopolymerization accelerator, a thermal polymerization inhibitor, a resin plasticizer, etc. are also used.

The photosensitive layer needs to have oil sensitivity. The oil-sensitivity referred to here means that after the photosensitive layer is transferred,
This means that when ink is supplied using an offset printing machine or the like, a photosensitive layer to which ink has been sufficiently transferred can be retained.

Photopolymerizable compounds include monomers and polymers.

At least one selected from prepolymers is applied.

The photopolymerizable compound is not particularly limited, but preferably one that can plasticize the thermoplastic resin at room temperature.

Typical compounds include 2-hydroxyethyl (meth)acrylate, ethylene glycol diacrylate,
Diethylene glycol diacrylate, 1.6 hexanediol di(meth)acrylate, trimethylolpropane triacrylate, pentaerythritol triacrylate, dipentaerythritol hexaacrylate, etc., these ethylenically unsaturated compounds may be used alone or as necessary. More than one species may be used.

The photodegradable compound is preferably a combination of a derivative such as an 0-naphthoquinone diazide carboxylic acid adduct and a thermoplastic resin, but is not particularly limited to this.

As the thermoplastic resin (organic polymer binder), a thermoplastic, non-photopolymerizable polymer that has excellent compatibility with photopolymerizable compounds can be used. For example, polyvinyl chloride,
Base rubbers such as poly(meth)acrylic esters, epoxy resins, polyurethane resins, cellulose derivatives (e.g., ethyl cellulose, nitrocellulose), polyamide resins, polyvinyl acetal resins, diallyl phthalate resins, butadiene-acrylonitrile copolymers, etc. Depending on the required physical properties, one or more of these thermoplastic substances may be included.

As photopolymerization initiators, we mainly use those with low absorption in the visible light region, those with good compatibility with photopolymerizable compounds, and those with photochemically intersystem cross quantum efficiency close to 1.
Preferred examples include benzophenone, benzoin ethyl ether, benzyl dimethyl ketal, azobisisobutyronitrile, 2-chlorothiozanzone, 2-methylthiozanzone, 2-ethylthiozanzone, 2-isoprobylthiozanzone, Examples include 4'-isopropyl-2-hydroxy-2-methylpropiophenone, and a photopolymerization accelerator may be used in combination to increase the photopolymerization initiation efficiency. As this photopolymerization accelerator, there are known aromatic-aliphatic tertiary amines, etc.For example, there are Mihirazketone, 4.4''-bisjethylagonobenzophenone, etc.Some accelerators may turn yellow. Therefore, the selection is made taking into consideration the promoting efficiency, yellowing, compatibility with the initiator, and the energy and wavelength range of the actinic light to be used.

Most thermal polymerization inhibitors are aromatic derivatives. What is important in selecting a thermal polymerization inhibitor is the amount added and compatibility; the amount must be such that it does not interfere with the generation of radicals for photopolymerization, and at the same time it must suppress radicals thermally. Hydroquinone, p-methoxyphenol, t-
Examples include butylcatechol and pyrogallol. However, the present invention is not controlled even if non-aromatic compounds are combined.

As the colorant that can be applied to the photosensitive layer, conventionally used dyes or pigments can be used. It is also possible to mix several dyes or pigments to obtain the required hue. Note that in the present invention, it is not necessary to use a colorant in the image forming material.

The thickness of the photosensitive layer on the plate material is usually 0.5 to 2, because the transfer photosensitive layer on the plate material becomes the image area.
It is desirable to determine the thickness of the photosensitive layer of the image forming material so that it is in micrometers (μm).

If the photosensitive layer is partially transferred by cohesive failure, the thickness of the photosensitive layer of one image-forming material may be greater than the above-mentioned thickness.

The method of using the image forming material having the above composition is as follows:
The transparent support side of the image forming material and the image surface of the mask original plate are superimposed, a transparent and flexible film is pressed over the mask, and the image is exposed from the mask side, and the mask original plate and then the protective film are exposed. The 28 plate itself can be obtained without any development process by transferring the removed photosensitive layer and the object to be transferred onto an anodized aluminum plate or the like while applying heat, pressure, speed, etc. between nip rolls.

Further, when performing this image formation, the original film and the image forming material do not need to be in close contact with each other. Furthermore, laser exposure can also be performed without using an original mask.

The transparent and flexible film used for this image exposure is polyolefin, such as polyethylene. Regardless of the temperature, it tends to swell due to heat, so it cannot be said to be preferable for use for this purpose because it is not possible to bring the mask and the image forming material into sufficient contact.

Also, in terms of transparency, methacrylic plates and the like can be used because they have an easy bottom shape, but they are inferior in terms of flexibility.

On the other hand, if the film is a polyester film, such as polyethylene terephthalate, it can sufficiently transmit actinic rays and does not expand or contract much when exposed to heat, so it is fully applicable to this purpose.

The plate material for the plate to be transferred is most preferably surface-oxidized metal aluminum, but it is not necessarily metal at all, and any material may be used as long as it does not swell with moisture.

The planographic plate material is a material that has hydrophilic properties or can be treated to make it hydrophilic, such as an aluminum plate, a zinc plate,
These include stainless steel plates, polyester sheets, composite materials of plastic and metal, paper, etc., and are materials that have undergone treatments such as graining, anodization, and hydrophilic layer coating.

In the present invention, transfer is preferably performed at a nip between rollers, and transfer between a metal roller and an elastic roller is suitable. A metal roller is heated to a temperature of 50 to 120°C, preferably io'c or less, and a desired transfer pressure is applied to perform the transfer. Also, the transfer speed is 1m
It is preferable to perform the transfer at a speed of 1/min or less; if the transfer is performed at a speed exceeding this, the transfer temperature must be raised considerably, and the image may become distorted or blurred, making it impossible to obtain good reproducibility. .

After the transfer, the photosensitive layer is preferably post-exposed or heated. In particular, heat treatment is desirable, and heating can contribute to improving the rigidity of the lithographic plate. Appropriate heating is 120 to 250''C.

The present invention will be described in more detail with reference to two examples below, but the present invention is not limited thereto. In example.

Parts refer to parts by weight.

Example 1 A photosensitive layer solution having the following composition was prepared.

Diallylisophthalate prepolymer 22.0 parts (manufactured by Daiso Co., Ltd.) KAYARAD-DPHA 7.0 parts (manufactured by Nippon Kayaku Co., Ltd.) Benzophenone (manufactured by Daiichi Kasei Co., Ltd.) 0.5 parts EAB
(Manufactured by Hodogaya Chemical Co., Ltd.) 0.2 parts Leuco crystal violet 3.0 parts Methyl ethyl ketone 40.0 parts Toluene
10.0 parts xylene
1093 parts This photosensitive layer solution was applied to a polyethylene terephthalate film (thickness 200 mm) as a support.
µ) to a dry film thickness of 2.5 µm.

The colored photosensitive layer formed on the transparent support and the protective film were laminated together using a ξ inator so that they were in contact with each other, to obtain the desired image forming material.

The transparent support side of this image forming material was brought into close contact with the silver salt side of the original positive mask, and the UV printer HMW201KB (
(manufactured by Oak Seisakusho Co., Ltd.) was used to apply actinic rays of 50 mj/cm''.The image forming material and the original positive mask were peeled off, the protective film was further peeled off, and a 20% sulfuric acid solution was used at a bath temperature of 20'' C1 current density. An image forming material from which the protective film has been removed is adhered to an aluminum plate (lithographic plate material) treated at 20OA/rrf for 30 minutes using a Fast Laminator 8 B-700 special model (manufactured by Taisei ξ Oak Co., Ltd.). and pressure 4kg/cm2. Passing speed 35cm/mi
When the photosensitive layer was transferred using a nip between a metal roller surface temperature of 75° C. and an elastic rubber roller (hardness: Shore A: 70), the thickness of the photosensitive layer in the unexposed area was 2.0 μm. Further, heat treatment was performed at 200″C for 530 minutes.

This means that a lithographic plate was produced without any developer treatment. Furthermore, when the printer was attached to a Toyo Blue Bar proofing machine (manufactured by Toyo Ink Manufacturing Co., Ltd.) for printing, it was possible to print 250 Kikuzen-sized prints with no background stains.

Example 2 A three-dimensionally crosslinkable polyethyleneimine-containing aqueous epoxy resin composition containing 50% by weight of colloidal silica was dried on a 0.2 mm thick polyester film using a bar coater, resulting in a film thickness of 40 μm. Coat it like this,
It was heated and cured at 150°C.

A photosensitive layer was transferred to this plate material in the same manner as in Example 1, and heat treated at 150° C. for 120 minutes.

When a printing test was conducted in the same manner as in Example 1, good printed matter was obtained.

Claims (1)

[Scope of Claims] 1. An image forming material having a support, an oil-sensitive photosensitive layer and, if necessary, a protective film is image-exposed and the exposed and unexposed areas of the photosensitive layer are tackified during transfer. If there is a protective film, the protective film is removed, and the surface of the photosensitive layer is placed on a lithographic plate material that has hydrophilic properties or can be treated to make it hydrophilic, and the unexposed areas of the photosensitive layer are removed. A lithographic printing plate characterized in that a part or all of the above is transferred onto the plate material. 2. A method for producing a printing plate, characterized in that the transfer according to claim 1 is carried out by cohesive failure of the photosensitive layer in unexposed areas. 3. A method for producing a lithographic printing plate, characterized in that the transfer according to claim 1 is carried out in a roller nip in which one roller has a surface temperature of 50 to 120°C. 4. The method for producing a lithographic printing plate according to claim 3, wherein the transfer speed is 1 m/min or less. 5. The method for producing a lithographic printing plate according to any one of claims 2 to 4, wherein a heat treatment at 120 to 250°C is performed after the transfer.