JPH0781025A - Process printing film - Google Patents

Abstract

PURPOSE:To form a hydrophilic ink holding layer between a hydrophobic photosensitive layer and a support layer, allow a hydrophilic layer formed on a base film to appear on the fottom face of the ink holding layer when a pit is formed by a laser beam, whereby water-base ink is easily introduced, and hold an amount of ink necessary for sharp printing. CONSTITUTION:A process printing film has a hydrophilic ink holding layer provided between a hydrophobic photosensitive layer and a support layer, and the photosensitive layer is formed of nitrocellulose carbon black, a bonding resin and a water repellent. It is preferable that the nitrocellulose has 11.5 to 12.2% of the nitrogen component and 1 to 1/8 sec of a solution viscosity. The carbon black makes dispersion easy. A polyester resin may be used as the bonding resin, but an aromatic polyester is preferable. As the water repellent, a silicon compound, a fluorine compound and a copolymer of these compounds and other indgredients or a graft copolymer thereof. The hydrophilic ink holding layer is formed on a support layer made of PET and the like as a thin film of AI, ITO, SiO2. and the like.

Description

Detailed Description of the Invention

[0001]

[Industrial application] The present invention relates to a printing film for plate making.

[0002]

2. Description of the Related Art A printing film for plate-making uses a laser beam to hold ink in pits formed on it, and transfers the array pattern of the pits to paper to produce a printed matter. The original plate. In order to hold the ink in the pits, the ink is applied on the film on which the pits are formed, and then the excess ink adhering to the surface is scraped off.

At this time, if the affinity between the surface of the photosensitive layer and the ink is high, the excess ink on the surface of the photosensitive layer cannot be completely removed, and the printed matter is stained. Since an aqueous material is used as the ink, in order to solve this problem, the hydrophobicity of the photosensitive layer itself forming the surface on which the ink is applied is increased.

However, if the photosensitive layer is too hydrophobic, the ink will not be sufficiently retained in the pits and the printed matter will be incomplete.

In the past, in order to solve this problem, it was necessary to control the hydrophobicity and characteristics of the photosensitive layer so that the printed matter became clear.

[0006]

The problem to be solved by the present invention is to prevent ink from adhering to the surface of the photosensitive layer and to retain the ink only inside the pits formed in the photosensitive layer. It consists in constructing a printing film.

That is, a printing film for plate making is characterized in that a hydrophilic ink holding layer is provided between a hydrophobic photosensitive layer and a supporting layer. The photosensitive layer is composed of nitrocellulose, carbon black, a binder resin, and a water repellent, and an additive such as a crosslinking agent may be added if necessary.

Nitrocellulose has a nitrogen content of 10 to 40.
%, The degree of polymerization varies, but the nitrogen content is 11.5-1.
2.2%, solution viscosity of 1 to 1/8 second is preferable,
You may mix 2 or more types as needed.

In order to facilitate the dispersion of carbon black, color chips or color paste in which carbon black is dispersed in nitrocellulose may be used.

As the binding resin, there is polyester resin, but aromatic polyester is preferable.

As the water repellent, a silicone compound, a fluorine compound and a copolymer or a graft of these with other components are used, and the addition amount thereof is such that the surface wetting index is 36 dyn /
It is set to be not more than 0.1 cm based on 100 parts of the solid content of the coating solution.
1 to 5 parts, preferably 0.2 to 2 parts are used.

The hydrophilic ink retaining layer is formed as a thin film of Al, ITO, SiO ₂ or the like on a support layer such as PET. Forming means is vacuum deposition, sprinkling, coating,
It is a known means such as laminating.

[0013]

EFFECT OF THE INVENTION By using the film having the above structure,
When forming pits with a laser beam, a hydrophilic layer formed on the base film appears on the bottom surface of the pits, the water-based ink easily flows in, and the amount required for clear printing is retained.

At the same time, since the photosensitive layer is hydrophobic, ink can be prevented from adhering to its surface.

[0015]

【Example】

(Examples 1 to 3) Nitrocellulose RS1 / 4 (manufactured by Daicel Chemical Industries, Ltd., solid content 70%) 7.7 parts, color paste ANP-C-903 black (manufactured by Toyo Ink, carbon black 12%, nitrocellulose) 18
%) 24.6 parts, polyester resin Byron 20SS
(Toyobo, solid content 30%) 43.3 parts, crosslinking agent Super Beckamine L-105-60 (Dainippon Ink, solid content 60%) 5.4 parts, BYK CATALLYST 45
0.4 (manufactured by BYK, solid content 40%), a silicon compound and a fluorine compound were added as shown in Table 1, and 18.7 parts of methyl ethyl ketone were dissolved and mixed to obtain a coating solution.

On the other hand, as an ink holding layer on the surface of polyethylene terephthalate film (thickness 100 μm), Table 1
The material shown in 1 was formed by vacuum vapor deposition to a thickness of 1000 angstrom, and the above coating solution was applied thereon by an applicator to a thickness of 7 μm and dried at 120 ° C. for 3 minutes.

Pits were formed on the obtained film with a laser beam having a focal depth of 10 μm and printed with a water-based ink to evaluate the background stain and the sharpness of the printed matter.

The results are shown in Table 1.

[0019]

Comparative Example A polyethylene terephthalate film having no Al thin film was used in Example 1, and the same evaluation was performed.

The results are shown in Table 1.

[0021]

[Table 1]

Claims (1)

[Claims] 1. A printing film for plate making, comprising a hydrophilic ink holding layer provided between a hydrophobic photosensitive layer and a support layer.