JP2001171253A - Wrapping body of lithographic printing original plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wrapping body of a lithographic printing original plate laminate provided with a photosensitive layer sensitizing with infrared laser beams without developing the lowering of the sensitivity of the layer. SOLUTION: This wrapping body is for wrapping a lilhographic printing original plate by laminating pulp-board paper on the top surface and on the undersurface of the lithographic printing original plate laminate, which is produced by providing the photosensitive layer sensitizing with the infrared laser beams on an aluminum support, under the state that a steam screening layer is provided at least on the surface contacting with the photosensitive layer of the pulp-board paper.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lithographic printing plate precursor laminate in which a photosensitive layer sensitive to infrared laser is provided on an aluminum support.

[0002]

2. Description of the Related Art In a photosensitive lithographic printing plate (digital thermal plate) provided with a photosensitive layer containing a photosensitive composition for infrared laser, a reaction occurs near an aluminum support because heat by IR exposure escapes to the aluminum support. It is liable to be weak, and it is necessary to form an image well only by the reaction of the upper layer of the photosensitive layer. In such a digital thermal plate, the photosensitive layer is very easily affected by moisture as compared with the conventional PS plate, and the image forming property is changed by the influence of moisture during storage. As one of the packaging materials for the PS plate, a thick protective patch (pulp board paper, hereinafter also referred to as a patch) is used to reinforce the plate bundle. If it contains moisture,
Water emanating from the contact ball with the passage of time passes through the photosensitive layer protective paper (hereinafter referred to as slip sheet) and affects the photosensitive layer.
In particular, when the product is packaged in a sealed state, moisture easily reaches the photosensitive layer, which causes a decrease in sensitivity.

[0003]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a lithographic printing plate precursor laminate provided with a photosensitive layer which is exposed to an infrared laser without causing a decrease in sensitivity.

[0004]

The object of the present invention is to provide a lithographic printing original plate in which pulp board paper is laminated on the upper and lower surfaces of a lithographic printing original plate laminate having a photosensitive layer exposed to infrared laser on an aluminum support. This is achieved by the above-mentioned package, wherein the package is provided with a water vapor blocking layer on at least a surface of the pulp board paper which is in contact with the photosensitive layer.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS [Pulp board paper] In the present specification, pulp board paper or padding ball is pulp board paper for packaging a photosensitive lithographic printing plate precursor, and is wood chemical pulp, groundwood pulp, waste paper. And all known pulp board papers manufactured using such as a raw material. For example, a packing material (contact ball) described in JP-A-8-3898 can be mentioned. The pulp board paper in the present invention,
These pulp board papers are characterized by having a water vapor barrier layer at least on the surface of the lithographic printing plate precursor that is in contact with the photosensitive layer.

[0006] The water vapor barrier layer may be present at least on the side of the pulp board paper which is in contact with the photosensitive layer of the lithographic printing plate precursor, and may not be provided on the side which is not in contact with the photosensitive layer. Accordingly, one embodiment of the present invention includes the package shown in FIG. However, in the case where the water vapor barrier layer is provided only on one side, the pulp board paper may be easily warped due to environmental humidity. In such a case, it is preferable to provide the water vapor barrier layer on both sides. In addition, when pulpboard paper provided with a water vapor barrier layer on both sides is used, there is no need to use the pulpboard paper separately in the upper and lower parts in production,
There is also the aspect that it is simple and preferable. As a method of providing a water vapor barrier layer on one or both sides of pulp board paper, that is, a layer that blocks the release of water vapor, there are coating, impregnation or lamination of a water vapor barrier resin, but more emphasis was placed on water vapor barrier properties. In this case, resin coating or lamination is preferred.

[0007] Examples of the water vapor barrier resin for coating or laminating include low density polyethylene (LDPE), high density polyethylene (HDPE), linear low density polyethylene (L-LDPE), and ethylene / vinyl acetate copolymer (EVA). ), Ethylene-ethyl acrylate copolymer (E
EA), ethylene / acrylic acid copolymer (EAA), ionomer, polypropylene (PP), polymethylpentene (TPX), polyester (PET), etc., with low density polyethylene being particularly preferred. In the present invention, the water vapor barrier layer refers to a layer that does not substantially transmit water vapor.

As a method for applying the above-mentioned resin to pulp board paper, various methods known in the art are used, for example, extrusion coating, calendar coating, curtain coating, slot orifice coating. , Rod (bar) coating, brush coating, spray coating, dip coating, bead coating, brush coating, spray coating, multilayer simultaneous coating, electrostatic coating, electrodeposition coating, etc. . Although the coating thickness depends on the type of the resin, it is preferably 5 from the viewpoint of water vapor permeability.
μm or more, more preferably 10 μm or more, and most preferably 20 μm or more. When storing or packaging the lithographic printing original plates in layers, the pulp board paper that has been subjected to the above treatment is placed above and below the plate bundle so that the treated surface (the surface provided with the water vapor blocking layer) is on the photosensitive layer side. And laminate.
In this case, the pulp board paper and the lithographic printing original plate may be brought into contact with each other via a slip sheet. Also, when stacking the lithographic printing original plates, an interleaf may be interposed therebetween.

When the planographic printing plate is larger in size than the pulp board paper, the pulp board paper can be used by being bonded to an appropriate size. For example, a pulp board paper having a lithographic printing plate having a dimension divided into two or four may be used with an adhesive tape or the like.

The lithographic printing original plate provided with a photosensitive layer sensitive to infrared laser according to the present invention may be any lithographic printing original plate provided with a photosensitive layer sensitive to infrared laser. 29292 and JP-A-7-20629.

[0011]

Next, examples of the present invention will be described in detail with reference to comparative examples. All percentages in the following Examples and Comparative Examples are% by weight unless otherwise specified.

Example 1 A bundle was prepared by laminating 30 digital thermal negative plates (LH-NI manufactured by Fuji Photo Film Co., Ltd.) with a photosensitive layer protective interleaf sandwiched between the plates. Pulp board paper of the same size as the plate
A pulp board paper [a] was prepared by laminating low-density polyethylene having a thickness of 10 μm on both surfaces of a contact ball described in Example 3 of JP-A-3898 (water content: 10.6%) by dry lamination. This pulp board paper was set above and below the digital thermal negative plate bundle with the bundle interposed therebetween, and this was wrapped with a moisture-proof sheet to obtain a package [A]. After leaving the package body [A] in the environment of 45 ° C. for 3 days, return to the normal temperature environment, open the moisture-proof sheet, and place the first plate of the bundle in contact with the pulp board paper via interleaving paper. Thermal Plate Setter (Creo Trendsette
After exposing the image under the specified conditions in r), heat it with a preheat oven (SPC Mini manufactured by Wisconsin), develop it with an automatic developing machine (LH-900H manufactured by Fuji Photo Film Co., Ltd.), and visually check the image formation state. evaluated. Table 1 shows the evaluation results.

Example 2 The procedure of Example 1 was repeated except that low-density polyethylene having a thickness of 40 μm was provided on both sides of the pulp board paper by extrusion coating. A package [B] was prepared and evaluated in the same manner as in Example 1. Table 1 shows the results.

[Example 3] The digital thermal positive plate of Example 2 was changed to LH-PI manufactured by Fuji Photo Film Co., Ltd., and pulp board paper [b] was used in the same manner as in Example 2 to obtain a package [ C], and the same process was carried out using a positive developer except that heating in a preheat oven was not performed in the process after exposure after standing and left under predetermined conditions, and the image formation state was visually evaluated. The evaluation results are shown in Table 1.

Comparative Example 1 A pulp board paper [d] was prepared in the same manner as in Example 2 except that the water vapor barrier layer was not provided.
A package [D] was prepared. Thereafter, all evaluations were performed in the same manner as in Example 1. Table 1 shows the results.

[0016]

[Table 1]

Evaluation of image formation ○: Good image formation ×: Poor image formation

As is evident from the above results, a lithographic printing plate precursor package made from pulp board paper provided with a water vapor barrier layer and preserved has good image forming properties after development. (Examples 1 to 3). On the other hand, those using the conventional pulp board paper were poor in image formability.

[0019]

EFFECT OF THE INVENTION The lithographic printing plate package of the present invention, in which pulp board paper having a water vapor barrier layer is laminated on the upper and lower surfaces of the lithographic printing plate precursor, provides excellent image formation without lowering sensitivity. A lithographic printing plate precursor having good properties is obtained.

[Brief description of the drawings]

FIG. 1 shows a sectional view of a package of a lithographic printing original plate of the present invention.

FIG. 2 is a cross-sectional view of a lithographic printing plate precursor package of the present invention.

FIG. 3 is a cross-sectional view of a conventional lithographic printing plate precursor package.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Pulp board paper 2 ... Water vapor barrier layer 3 ... Photosensitive planographic printing plate 4 ... Photosensitive layer

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2H025 AA00 AB03 AC08 AD01 AD03 CC20 DA18 2H096 AA07 BA16 CA20 EA04 LA30 2H114 AA04 EA10

Claims (1)

[Claims] A lithographic printing plate precursor comprising: a lithographic printing plate precursor having a pulp board paper laminated on an upper surface and a lower surface of a lithographic printing plate precursor having a photosensitive layer exposed to an infrared laser on an aluminum support; The above-mentioned package, wherein a water vapor barrier layer is provided on at least a surface of the board paper which is in contact with the photosensitive layer.