JPH03284992A - Printing plate material and preparation thereof - Google Patents

Abstract

PURPOSE:To obtain a printing plate material capable of being directly subjected to plate making from a digital signal and requiring no wetting water and imparting excellent printing image quality by successively laminating an ink absorbing layer, an ink repellent mesh layer, a heat-meltable layer, a thermal adhesive release layer and a cover film to a water-resistant support. CONSTITUTION:A printing plate material is formed by successively laminating an ink absorbing layer 2, an ink repellent mesh layer 5, a heat-meltable layer 3, a thermal adhesive release layer 4 and a cover film 6 to a water-resistant support 1. The printing plate material is subjected to plate making by applying thermal printing to the printing plate material on the side of the cover film and subsequently mechanically removing the cover film. In the thermally printed part of the printing plate material, the heat- meltable layer is melted to be bonded to the cover film through the thermal adhesive release layer and removed along with the cover film and the ink repellent mesh layer appears to become a non-image part. In the thermally unprinted part of the printing plate material, the heat-meltable layer is not melted and, therefore, the thermal adhesive release layer bonded to the cover film and the heat-meltable layer are released and the heat-meltable layer remains as it is to become an image part.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention does not require complicated steps such as exposure and development;
This relates to printing plates that can be easily plate-made using a thermal printing device, and can also be lithographically printed on parts without the need for dampening water. In particular, printing for so-called direct plate-making, which allows plate-making and printing directly from a computer, etc. This relates to printing plate materials.

<Conventional technology> Conventionally, as a system that can directly make plates from digital signals of documents and images created and edited using word processing sensors, desktop publishing systems, etc.
) a combination of electrophotography and laser scanning exposure; (a method in which a BL silver salt sensitive material is exposed to semiconductor or He-Ne laser; (C) a method in which the hydrophilic surface layer of support-E is destroyed by electrical discharge; (d) An ink-friendly layer is provided on a support having a hydrophilic surface by thermal transfer. (e) A hydrophilic layer containing a heat-melting substance is thermally printed with a thermal head to become ink-friendly. , (f) A number of methods have been proposed in which a thermoplastic resin film layer on a porous support is thermally printed with a thermal head to form a stencil.

<Problems to be Solved by the Invention> However, in the systems (a) and (bl), the laser exposure device is complicated and large-scale, and development processing must be performed subsequently, and the process is complicated. It has the disadvantage of high cost.Furthermore, wet development treatment is unfavorable in terms of labor hygiene and danger.

The system that solved this problem is (C), (d)
, (e), and the process is simple and the device is small because the development process can be done in a dry manner. However, since the next printing process is a lithographic printing method that requires dampening water, skill is required to adjust the supply balance of dampening water and oil-based ink, and daily maintenance and cleanup are complicated. and
The simplicity of plate making becomes meaningless.

There is (f) as a method to solve n points between the above,
Since it is a stencil printing method, the print quality is not satisfactory, as the edges of the image are not sharp and the text is difficult to read, and the image density is low.

<Means for Solving the Problems> The present invention provides an ink-absorbing layer, an ink-repellent mesh layer, a heat-melting layer, a heat-adhesive release layer, and a water-resistant support.
A printing plate material in which a cover film and a cover film are sequentially laminated is thermally printed from the cover film side using a thermal printing device to melt the heat-melting layer in the non-image area and adhere to the cover film. By mechanically peeling off and removing the material, plate making can be done directly from digital signals from word processing sensors, desktop publishing systems, etc., without the need for complex processes such as exposure and development, and it is possible to To provide a printing plate material with excellent print image quality and a plate-making method thereof, which can perform lithographic printing without requiring water and with ease equivalent to that of a copying machine.

As the water-resistant support of the present invention, polyethylene terephthalate (PET) film used in heat-sensitive recording and having a thickness of 5 to 100 μm, water-resistant paper, and the like can be used.

As the ink-absorbing layer of the present invention, water-absorbing polymers such as Sunwet manufactured by Sanyo Kasei and Sumikagel manufactured by Susumu Kasei can be used alone or as a composite with other synthetic resins. Other synthetic resins that are highly compatible with the water-absorbing polymers mentioned above include
Preferably, vinyl chloride resin or polyethylene resin is used. The mixing ratio of the water-absorbing polymer and other synthetic resin in the case of forming a composite is such that the water-absorbing polymer accounts for 50% by weight or more, preferably 70% by weight or more, in order to ensure water absorption.

The heat-melting layer of the present invention needs to have mechanical strength and ink receptivity that can be melted by heating with a thermal printing device and can withstand printing after plate making, and has a glass transition temperature of 50 to 1.
Polyester resins, vinyl chloride resins, acrylic resins, vinyl resins, etc. in the range of 10'C can be used.

As the polyester resin, it is preferable to use a saturated polyester resin, and as the vinyl chloride resin, it is preferable to use a polyvinyl chloride resin or a polychlorinated vinyl acetate resin. In addition, examples of acrylic resins include polyethyl acrylate, polymethyl chloroacrylate,
Vinyl resins include polymethyl methacrylate, polyacrylonitrile, polyacrylonitrile, ethylene-ethyl acrylate copolymer, acrylic-styrene copolymer, etc., polystyrene, polydivinylbenzene,
It is preferable to use polyvinyltoluene, styrene-butadiene copolymer, etc. alone or in combination. Note that 0.01 to 20% by weight of coloring pigments or dyes may be added to provide plate inspection properties after plate making.

When the heat-adhesive peeling layer of the present invention is thermally printed with a thermal head etc., the heat-melting layer of the thermally printed portion adheres;
The thermally fused layer in the area that is not thermally printed is :l(:i ff
111. As the heat-adhesive release layer, thermoplastic resins such as polyvinyl chloride resins and polyester resins, which have a higher heat softening point and glass transition point than the heat-melting layer, are used. It can be formed using Also,
In order to improve the releasability of the areas not thermally printed, several percent of silicone oil for coating 4 may be added.

As the ink-repellent mesh layer of the present invention, a mesh made of polyester or stainless steel, which is generally used in screen printing, and whose surface is coated with a silicone resin can be used.

The cover film of the present invention must have heat resistance that will not melt due to thermal printing by a thermal head, etc., and a layer to prevent sticking of a thermal head is provided on the outside.
A PET film with a thickness of 5 to 50 μm can be used.

The method for laminating the printing plate material of the present invention includes:
A coating solution prepared by dissolving or dispersing the water-absorbing polymer, which is the ink-absorbing layer, alone or in combination with other synthetic resins in an appropriate organic solvent is applied to the surface so that the dry film thickness is 50 to 500 μm. layered with an ink-repellent screen mesh coated with silicone resin and allowed to dry. Coating liquids for a heat-melting layer and a heat-adhesive release layer dissolved or dispersed in an appropriate organic solvent are applied thereon, dried, and a cover film is pressed onto the layer to prepare a printing plate material.

In this case, the thickness of the heat-melting layer is preferably 1 to 20 μm. If the thickness of the heat-fusible layer is less than 1 μm, the printing durability during printing will be insufficient, and if it is more than 20 μm, there will be insufficient heat-melting at the bottom of the heat-fusible layer during thermal printing, causing the cover of the heat-fusible layer to deteriorate. Adhesion to the film will be incomplete, causing print stains in non-image areas. Further, the thickness of the heat-adhesive peeling layer is preferably 0.5 to 5 μm.

The method for making a printing plate material of the present invention is a conventional heat-sensitive 7' I
After thermal printing is performed from the cover film side using a J79 thermal head, the cover film is mechanically removed. That is, in the thermally printed portion of the printing plate material, the thermally fusible layer melts and adheres to the cover film via the thermally adhesive peeling layer, and is removed together with the cover film to reveal the ink-repellent mesh layer. It becomes a non-image part. In addition, in the areas of the printing plate material that are not thermally printed, the heat-melting layer does not melt, so the heat-adhesive release layer attached to the cover film and the heat-melting layer separate, and the heat-melting layer remains as it is. This becomes the image section.

<Function> For a printing plate made by the plate-making method of the present invention using the printing plate material of the present invention, printing using an aqueous paste ink is preferred. In this case, water-based ink adheres to the thermally fused layer in the thermally printed image area because the thermally fused layer remains as it is, and in the thermally printed non-image area, the surface has a low surface tension. Since the ink-repellent mesh layer coated with silicone resin is exposed, it effectively repels water-based ink and prevents water-based ink from adhering.

In addition, when a very small amount of water-based ink adheres to the ink-repellent mesh layer, the water-based ink is absorbed by the ink-absorbing layer through the ink-repellent mesh layer, and no water-based ink remains on the surface of the printing plate, causing background stains in non-image areas. It is possible to obtain printed matter with excellent print quality and less blemishes.

<Example 1> As an ink absorption layer, 70 parts by weight of a water-absorbing polymer (Sumikagel S P-520 manufactured by Sumikagaku Co., Ltd.), 30 parts by weight of polyethylene resin (Vylon 200 manufactured by Toyobo Co., Ltd.), and 1 part by weight of toluene were used.
50 parts by weight was dispersed in a paint shaker for about 30 minutes to form a dry film thickness of 1 on a 50 μm thick PET film.
00 μm using a bar coater, and before completely drying, a 70-mesh polyester screen mesh whose surface was coated with silicone resin (TSW811 manufactured by Toshiba Silicone Co., Ltd.) was layered and dried.

On top of that, 20 parts by weight of carbon black and acrylic resin (BR-64T manufactured by Mitsubishi Rayon) were added as a heat-melting layer.
g・55°C) 60! i parts and 6 parts of methyl ethyl ketone
0 parts by weight and 60 parts by weight of toluene were dispersed in a paint shaker for about 1 hour, and the mixture was coated with a bar coater to a dry thickness of 10 μm and dried.

Next, polyester resin (Toyobo Byron 200
Tm=163°c) 50 parts by weight, silicone oil (
0.5 parts by weight of TSF4701) manufactured by Toshiba Silicone and 100 parts by weight of methyl ethyl ketone were similarly dispersed, coated, and dried to obtain a 2 μm heat-adhesive release layer. A 5 μm I) ET film, which had previously been provided with an anti-sticking layer as a cover film, was pressure-bonded thereon to produce a printing plate material.

This printing plate material was heated from the cover film side to a thermal simulator (printing voltage 0.45 Mdot pulse width 2.
5 m, 5ec10n-off) to perform thermal printing, and then simply peeling off the cover film by hand completed the plate making of the printing plate.

Using the printing plate material of this example and the printing plate made by the plate-making method of this example, printing was performed using water-based ink on an offset printing machine AD-80 manufactured by Ryobi Imagix. A printed matter with excellent print quality and no background smearing in the image area was obtained.

<Effects> According to the printing plate material and its plate-making method of the present invention, plate-making and printing can be performed directly from a computer, etc. without the need for complicated processes such as exposure and development, or special inks or transfer ribbons. A printing plate material for so-called direct plate-making, which can be used for printing, and a lithographic printing plate that does not require dampening water were obtained. When this lithographic printing plate was used for printing with water-based ink, it was possible to obtain printed matter with excellent print quality, with no scumming in the non-image areas, and with the same ease of handling as a copying machine.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing the layer structure of the printing plate material of the present invention,
FIG. 2 is an explanatory diagram showing a method for making a printing plate material according to the present invention. 1 - Water resistant support 2 - Ink absorbing layer 3 - Heat melting layer 4 - Heat adhesive release layer 5 - Ink repellent mesh layer 6 - Cover film patent application Toppan Printing Co., Ltd. Representative Kazuo Suzuki

Claims (1)

[Claims] 1) An ink absorbing layer, an ink repellent mesh layer, a heat melting layer, a heat adhesive peeling layer, and a cover film are sequentially laminated on a water-resistant support. A printing plate material featuring: 2) The printing plate material according to claim 1 was thermally printed from the cover film side using a thermal printing device to melt the heat-melting layer in the non-image area and adhere it to the cover film. A method for making a printing plate material, which is characterized in that the cover film is then mechanically peeled off and removed.