JP2946702B2 - Lithographic printing plate, method for producing the same, and lithographic printing plate material used therefor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial application field> The present invention relates to a lithographic printing plate that does not require a dampening solution and does not require a process such as a wet development process, and can be easily made only by thermal printing. In particular, the present invention relates to a lithographic printing plate for so-called direct plate making that can directly make a plate from a digital signal of a computer or the like.

<Conventional technology> Conventionally, as a system for making a plate directly from digital data of a computer, a combination of laser scanning exposure and electrophotography, a resin layer or the like is changed by scanning with a high-power laser such as CO ₂ . There is a type in which a photosensitive resin and a silver salt photosensitive material are laminated and scanning exposure with an Ar laser is performed, and a type in which a semiconductor or a He-Ne laser is used to expose the silver master type.

In the method of (2), charging, exposure,
This requires at least a process of phenomena, and makes the device complicated and large. Further, the dry developing method has poor image quality and is not suitable for printing, while the wet developing method is not preferable in terms of occupational health and danger.

Further, a method of removing a non-image area by using a toner image as a resist is not preferable because a wet process is further increased.

In the method, a large output laser such as a CO ₂ or YAG laser itself is large, and the apparatus becomes huge and energy consumption increases. Further, the reliability such as the life of these lasers was not sufficient.

In this method, the silver halide photosensitive material is exposed to an Ar laser, the exposed area is blackened by wet development, and the entire surface is irradiated with UV to develop the photosensitive resin layer by a wet phenomenon. In addition to being complicated, there is a disadvantage that the cost of the plate material is high.

However, the method of (1) has a drawback that the cost is high due to the use of a silver salt and that it is a wet development.

On the other hand, a heat-sensitive melt transfer using a support having a hydrophilic surface as disclosed in JP-A-58-193154, JP-A-59-76260, JP-A-63-222857, and plate making by a wire dot method or thermal transfer. The method is widely used in printer applications because it can be processed in a dry manner and the process is simple, so that the apparatus is small and requires no maintenance. However, in these methods, thermal printing is performed on a thin substrate via a transfer layer made of wax, resin, pigment, and the like.

Furthermore, the above-mentioned printing plates are all offset printing plate materials that use water, and have various problems caused by water, such as the balance between ink and water, emulsification of ink, and the effect of temperature. It had been.

Further, Japanese Patent Application No. 02-086216 discloses a simple plate making method in which an ink repellent thermosensitive recording layer is thermally printed from above a protective sheet, and an ink receptive image portion is formed by removing the protective sheet. We have proposed a lithographic printing plate that does not require dampening water.However, there is a problem that the printing density is low and the image quality is poor because the minute uneven surface generated by destroying the fused part of the heat-sensitive recording layer becomes the ink receiving part. At present, there is no waterless printing plate that can be directly printed from digital data, and only the PS plate that combines photosensitive resin and silicone rubber is in practical use.

<Problems to be solved by the invention> An object of the present invention is to provide a small-sized apparatus and a dry process.
An object of the present invention is to provide an offset printing plate capable of making a plate directly from a digital signal of a computer or the like, a method of manufacturing the same, and a lithographic printing plate used for the method.

<Means for Solving the Problems> The present invention that achieves the above objects is achieved by providing a thermoplastic resin having a glass transition temperature in the range of 50 ° C. to 110 ° C. on a support and a hot-melt resin containing a silicone-based primer as a main component. A lithographic printing plate characterized by laminating a layer and a silicone rubber layer. In the production of a lithographic printing plate, a lithographic printing plate comprising a support, a hot-melt layer mainly composed of a thermoplastic resin having a glass transition temperature in the range of 50 ° C to 110 ° C and a silicone-based primer, and a silicone rubber layer is further laminated. Using a printing plate material, heat-print the non-image area from the silicone rubber side, then attach an adhesive sheet to the silicone rubber side of the printing plate, press and peel off the adhesive surface, and support the non-heat-printed part. A method of manufacturing a lithographic printing plate, characterized in that an image portion is formed by removing an upper laminate.

The printing plate thus obtained is placed on an ink-receiving support through a hot-melt layer mainly composed of a thermoplastic resin having a glass transition temperature of 50 ° C to 110 ° C and a silicone primer. Thus, a planographic printing plate having a silicone rubber ink repellent layer provided in a pattern is obtained.

<Function> The heat-sensitive recording layer of the printing plate of the present invention can be easily formed by a general method.

In addition, since a thermal recording method is used as a plate making method, plate making can be made directly from digital data, and does not include a wet process such as development. In addition, since thermal printing is performed from the silicone rubber side and the hot-melt layer containing the thermoplastic resin and silicone-based primer in the printed portion is hot-melted and simultaneously fused to the support and the silicone rubber, high printing durability can be obtained. In addition, when the non-printed part is removed with the adhesive sheet after printing, an ink-receptive support serving as an image area appears, so the non-printed part shows good ink receptivity, and a high resolution can be achieved by reducing the thickness of each layer. Is obtained. As a result, a printed matter having high image density and high image quality can be obtained.

In addition, in the non-image area where the thermal printing is performed, the silicone rubber layer remains on the surface, and the surface tension is extremely small, so that it has a property of repelling ink, and offset printing without using dampening water, that is, waterless lithographic printing. Becomes possible.

<Detailed Description of the Invention> Hereinafter, the present invention will be described in detail.

The plate material for a lithographic printing plate of the present invention is generally obtained by laminating a hot-melt layer and a silicone rubber layer on a support.

The support only needs to have ink receptivity,
Metals such as paper, plastic, for example, a polymer such as polyvinyl chloride or a metal plate such as brass, copper, stainless steel, and aluminum treated with lipophilicity, or a treated steel plate can be used.

The thermoplastic resin having a glass transition temperature in the range of 50 ° C. to 110 ° C. can be selected from polyester resins, PVC resins, acrylic resins, and vinyl resins. For example, a saturated polyester resin as a polyester resin, a polyvinyl chloride resin, a polyvinyl chloride acetate resin as a PVC resin, and polyethyl acrylate, polymethyl methacrylate, polymethyl methacrylate, polymethacrylonitrile, and poly as acrylic resin. Acrylonitrile, ethylene-ethyl acrylate copolymer,
Examples of the acrylic-styrene copolymer and vinyl resin include polystyrene, polydivinylbenzene, polyvinyltoluene, and styrene-butadiene copolymer.

In the case of a resin having a glass transition temperature of 110 ° C. or higher, the sensitivity cannot be sufficiently obtained under normal printing conditions of a thermal head, so that the resin cannot be easily melted by heat and the printing energy must be increased.
However, increasing the printing energy is not preferable because the silicone rubber on the surface is deteriorated, which may cause background stains during printing and may cause deformation of the printing plate. Also 50
If the temperature is lower than ℃, the adhesive strength is insufficient and sufficient printing durability cannot be obtained.

As the primer, a primer for silicone rubber is preferable, and specific examples include ME-151, ME-152, and ME-12.
1, ME-123 (all of which are trade names manufactured by Toshiba Silicone Co., Ltd.) and the like.

The content of the silicone primer is 35 to 70% by weight, preferably 40 to 65% by weight based on the solid content of the thermoplastic resin.
Is appropriate. In this case, if the content is more than this range, the adhesiveness between the hot-melt layer and the support becomes too strong, and when the non-printed portion is removed with an adhesive tape, no peeling is performed and no image is formed. On the other hand, if it is less than this range, the adhesion to the silicone rubber layer becomes weak, and sufficient printing durability cannot be obtained, which is not preferable.

Further, a lubricant can be added to the hot melt layer in order to improve the resolving power and the releasability of the non-printed portion from the support. Specifically, for example, Teflon powder, polyethylene powder, carnauba wax, polyethylene wax, paraffin wax, microclostalin wax, ester wax, candelilla wax,
Examples thereof include natural waxes such as hydrocarbon-based synthetic waxes, synthetic waxes, and various resins.

As for the silicone rubber, various thermosetting silicone rubbers containing dimethylpolysiloxane as a main component are used. The thermosetting silicone rubber includes a one-part type and a two-part type. In the one-part type, usually, a deacetic acid type, a deamine type, and a deamination type, which are obtained by reacting with moisture in the air under a small amount of an organotin compound, are usually used. Silicone rubbers such as alcohol type and deoxime type are exemplified. In two-pack type, Si-OH, Si-OR, Si
-H, Si-CH = CH ₂ siloxanes having reactive groups such as catalysts, specifically, silicone rubbers obtained by dehydration condensation, dealcohol condensation, dehydrogenation condensation, addition polymerization and the like. .

The method for producing a lithographic printing plate according to the present invention will be described below. 1 (a) to 1 (f) show the steps of producing a lithographic printing plate according to the present invention.

First, as shown in FIG.
A mixture of a thermoplastic resin having a temperature in the range of from 110 ° C. to 110 ° C. and a suitable organic solvent such as a primer and toluene is mixed by a disperser such as a ball mill, a paint shaker, an ultrasonic homogenizer, and a sand mill. The obtained mixture is applied on the support (1) by a conventionally known applicator such as an applicator, a spray coater, a bar coater, a dip coater, a doctor blade, and the like, and then heated and dried to form a hot melt layer (2). Then, silicone rubber is applied by a well-known applicator, and then heated and dried to provide a silicone rubber layer (3), thereby obtaining a lithographic printing plate material. The thickness of the hot melt layer (2) can be arbitrarily set, but is preferably 3 μm or more, and more preferably 5 to 100 μm. If the thickness of the silicone rubber layer (3) is too thick, the hot melt layer (2)
The heat energy is insufficient, so that the thickness is 50 μm or less, preferably 30 μm or less.

Next, as shown in FIG. 1 (b), the obtained lithographic printing plate material is scanned according to digital information by using a thermal head (4) such as a thermal printer or a thermal facsimile, and thermal printing is performed. At this time, the pressure is 0.1 ~ 10kg / cm
^{2. The} temperature is preferably 110 ° C. or higher.

As a heating method, laser scanning or photothermal conversion using a flash can be used instead of using a thermal head. After the thermal printing, as shown in FIG. 1 (c), an adhesive tape (7) is applied to the silicone rubber layer (3) side, and pressure is applied as shown in (d).

The pressure-sensitive adhesive sheet (7) used here is preferably a pressure-sensitive adhesive sheet (7) having a silicone-based pressure-sensitive adhesive (6) having adhesiveness to silicone rubber.

Further, a general adhesive may be applied to the support.

Next, as shown in FIG. 1 (e), when the adhesive tape (7) adhered is peeled off, the heat-melted layer (2) 'of the thermally printed portion is fused to the support (1), so It remains as an image area. In the non-printed area, the hot-melt layer (2) is peeled off from the support (1) together with the adhesive (6), and the ink-accepting support (1) is exposed to form a printed image area. A lithographic printing plate as shown in (f) is obtained.

In the lithographic printing plate thus obtained, the heat-melted layer (2) 'of the thermally printed portion is melted and firmly fused to the support (1). The presence of the silicone rubber layer (3) having a small tension makes the ink repellent. In addition, high printing durability is obtained due to strong adhesion of each layer. On the other hand, the non-printed portion shows good ink receptivity because the ink receptive support (1) appears after peeling,
High image density can be obtained.

For printing using the lithographic printing plate, a normal offset printing machine can be used, and if no dampening solution is supplied, waterless printing can be performed.

In addition, ordinary offset printing presses require a large number of rollers and controls to finely change the printing state of the ink and water balance. And the number of places to be controlled can be reduced.

<Example> Hereinafter, the present invention will be described in more detail with reference to examples.

(Example 1) Composition as heat-fusible substance, Is mixed with 50 g of 4 mmφ glass beads for 30 minutes using a paint conditioner to form a coating liquid for a hot-melt layer, and a 6 μm dry film thickness is formed on an oleophilic aluminum plate.
m with a bar coater. After drying, the composition as silicone rubber on it Was applied with a bar coater so as to have a dry film thickness of 7 μm to obtain a lithographic printing plate material.

Next, the lithographic printing plate material was thermally printed by a thermal printer, the silicone-based pressure-sensitive adhesive sheet was pressed, and then the pressure-sensitive adhesive sheet was removed. Thus, a lithographic printing plate having a good printed image was prepared.

This was printed with a commercially available offset printing machine (AD-80, manufactured by RYOBI MAGICS Co., Ltd.) using AQUALES V manufactured by Toyo Ink Mfg. Co., Ltd. without dampening water. As a result, the background area ratio of the thermally printed portion of the printout was 0.1% or less (Viewback III manufactured by Toyo Ink Mfg. Co., Ltd.), and the print image density of the non-thermally printed portion after printing 2,000 sheets was 1.2 or more ( A very high-quality printed material called Macbeth reflection densitometer RD-914) was obtained.

(Example 2) Composition as silicone rubber In addition, a silicone-based primer of a hot-melt substance was used for ME-
A planographic printing was prepared in the same procedure as in Example 1 except that 151 (primer manufactured by Toshiba Silicone Co., Ltd.) was used, and printing was performed in the same manner.
As a result, a high-quality printed matter free from background smear similar to that of Example 1 was obtained.

(Comparative Example 1) The following composition was used for the thermoplastic resin of the hot-melt layer of Example 1 using the thermoplastic resin Pylon GK590 (a polyester resin manufactured by Toyobo Co., Ltd.) having a glass transition temperature of 15 ° C. A lithographic printing plate was prepared in the same procedure as in Example 1, and printing was performed in the same manner. After printing 50 sheets, a part of the coating on the image area was peeled off, making printing impossible. Only printed copies were obtained.

(Comparative Example 2) The following composition was used for the thermoplastic resin of the hot-melt layer of Example 1 using the thermoplastic resin BY-139 (butyral resin manufactured by Denki Kagaku Kogyo KK) having a glass transition temperature of 110 ° C or higher. , A lithographic printing plate was prepared in the same procedure as in Example 1 except that the heat-sensitive recording layer of the printing plate was insufficiently melted due to insufficient energy applied to the thermal head. When the same printing was performed using this printing plate, the print image density was 0.4%.
Below, only very low quality printed matter was obtained.

<Effects> As described above, according to the planographic printing plate and the method of manufacturing the planographic printing plate of the present invention, an offset printing plate can be easily produced directly from digital data by dry processing using a thermal plate making method. In addition, the surface of the non-image area of the printing plate has high ink repellency, and can be used as a waterless plate that does not require etching treatment before printing or fountain solution during printing, and has high quality and high printing durability with no background contamination. Was obtained.

[Brief description of the drawings]

1 (a) to 1 (f) are explanatory views showing one embodiment of a method of manufacturing a lithographic printing plate according to the present invention in the order of steps. (1) ... support (2) ... hot melt layer (3) ... silicone rubber layer

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-3-281390 (JP, A) JP-A-61-118295 (JP, A) JP-A-4-113895 (JP, A) JP-A-3-11895 286899 (JP, A) JP-A-63-54286 (JP, A) JP-A-62-50760 (JP, A) JP-A-60-9799 (JP, A) (58) Fields investigated (Int. ⁶ , DB name) B41N 1/14

Claims (3)

(57) [Claims] A silicone rubber ink is provided on an ink-receiving support via a hot-melt layer mainly composed of a thermoplastic resin having a glass transition temperature in the range of 50 ° C. to 110 ° C. and a silicone primer. A lithographic printing plate comprising a repulsion layer provided in a pattern. 2. A lithographic plate comprising a heat-melting layer mainly composed of a thermoplastic resin having a glass transition temperature in the range of 50 ° C. to 110 ° C. and a silicone primer, and a silicone rubber layer laminated on an ink-receiving support. After performing thermal printing from the silicone rubber side using the printing plate material, an adhesive sheet is adhered to the silicone rubber side of the printing plate, the adhesive surface is peeled off after pressing, and the non-thermal printing portion on the support is printed. A method for producing a lithographic printing plate, comprising forming an image portion by removing a laminate. 3. A hot-melt layer mainly composed of a thermoplastic resin having a glass transition temperature in the range of 50 ° C. to 110 ° C. and a silicone-based primer, and a silicone rubber layer are laminated on an ink-receiving support. A lithographic printing plate material characterized in that: