JPS58181692A - Lithographic plate - Google Patents

Abstract

PURPOSE:To obtain a printing plate with an excellent printability which enables a stable printing simply by providing a porous recording layer comprising pigments and resins on a supporting body and a hydrophelic slick layer thereon in a double-layer construction in direct drawing type lithographic plate. CONSTITUTION:A coat liquid comprising particles of an inoragnic or oranic pigment such as titanium oxide with a size of 0.5-5mum, a binder resin for binding it in dispersion and an organic solvent for dissolving the resin is applied on a supporting body 2 to provided a porous recording layer 3 with a film thickness 10-30mum. The composition ratio of the pigment and the resin shall be 1/3-1/4 by weight. Then, a hydrophilic slick layer containing solid lubricant particle such as boron nitride and sulfur and hydrophilic resin at a rate of 1/2-20/1 by weight is formed on the recording layer 2 with a film thickness of 10mu. In the lithographic plate 1 thus formed, as a head 6 is pressed on the surface of a hydrophilic slick layer 4 through an ink ribbon 5, ink penetrates into the porous recording layer 3 to form a permeation image 7, which is used for offset printing or the like.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a master plate for lithographic printing, and more particularly to a direct dissemination type lithographic printing plate.

Lithographic printing plates are usually produced by creating a lipophilic image on a support such as a hydrophilic aluminum plate. The image area is required to have lipophilicity and water repellency, and the non-image area is required to have properties such as hydrophilicity, water retention and ink repulsion.

Depending on the method of producing the parent image area, there are original plates for pointillist lithography, original plates for electrophotographic lithography, original plates for photolithographic printing (so-called 233 plate), and the like.

Conventionally, the hydrophilic layer of a pointillist lithographic printing plate has been formed by coating a cellulose acetate film or a suitable support (or saponifying cellulose acetate with an alkali and filtering it into an aqueous phase and an aqueous phase). A lithographic printing original plate having a layer mainly composed of an ethylene-vinyl alcohol copolymer as a hydrophilic layer is also known.

However, printing using these lithographic printing plates requires strict control of the amount of water and ink supplied, making it impossible to perform stable printing, and the printing force is only 500~1.
It was about 1,000 copies.

The present invention is intended to eliminate the above drawbacks.

An object of the present invention is to provide an original plate for lithographic printing, which allows even unskilled persons to perform stable printing easily and has a printing durability of 5,000 to 10,000 copies.

That is, the lithographic printing original plate of the present invention has a porous recording layer and a hydrophilic slipping layer on a support, and the image area after image formation is durable, and there is no background stain in the non-image area. It is characterized by

As shown in FIG.
Use plastic, metal, or strong paper as a support (2
), and a porous recording layer (
3), and further provided with a two-layered layer on which a hydrophilic slipping layer (4) made of solid lubricant particles-f/hydrophilic resin is provided. The most practical method for forming this layer is to apply a coating liquid, so the coating film will be described in detail below.

First, the method for forming a porous recording layer will be described below.

The basic composition of the coating liquid consists of particles, a resin that uniformly disperses and binds the particles, and an organic solvent that dissolves the resin. As specific examples of particles, any inorganic or organic pigment can be used. - Examples include acid IL titanium, calcium carbonate, lead oxide, silicon oxide, barium sulfate, lead carbonate,
Alumina, clay, etc. can be used. On the other hand, resin (・
For example, binder resins used in paints and dyes may be used, such as polyol-based, phenyl-based, alkyd-based, acrylic-based, epoxy-based, polyurethane-based, modified cellulose-based resins, and mixtures thereof.

Crosstalk dispersion to obtain a 1r liquid is performed by a well-known method.

The second coating solution is applied to a durable support such as glass, metal, or tough paper, and dried to form a porous 1'-1g recording layer. Form. As for coating, it is good to apply the well-known coating method.As a result of intensive studies to obtain good recording characteristics of this coating film, the following woman was found to be the one.

First, the pigment/resin composition ratio has a significant effect on recording properties (related to the abrasiveness of the coating film), coating strength, adhesion to the support, and 1111I abrasion resistance, but all In order to meet
Must be in the range 1.

In addition, depending on the material type of the pigment, the particle size and shape of the pigment, I-
Although the full range described above may not be applicable, the range is 1/1 to 4/1, which is common even for different material compositions.
Ru. Regarding the particle size and interparticle distribution of the pigment, the particle size distribution should be as narrow as possible within the particle size range of 05 to 5 μm (taking into consideration porosity and surface roughness). Further, the appropriate thickness of the coating film is about 10 to 50 tt.

In addition, in order to improve the strength and solvent resistance of the coating film,
It is even more preferable to use a crosslinked binder resin. For example, a well-known method such as selecting a resin containing an ester resin or a polyurethane resin having a polyol group as the resin, and using a binder resin composition in which a compound or resin containing an iso-7 atom group is added as a crosslinking agent. Technology can be applied as appropriate.

7 (If the adhesion between the support and the porous recording layer to be provided is weak (・)
Providing an undercoat layer to improve IR power is an obvious method.

Next, we will look at the coating film formation method for the hydrophilic and slippery layer.
Bell. The basic composition of the coating liquid consists of solid lubricant particles (preferably 1-< is hydrophilic), a 1- hydrophilic binder resin that uniformly disperses and binds the particles, and a 4-organic solvent that dissolves the resin. Specific examples of the solid lubricant particles include boron nitride, sulfur, mica, tartar, ester 1)/(g!aluminum,
Fine powders of calcium/ium stearate, titanium sulfate, molybdenum sulfide, polyethylene, polyacetal, polytetrafluoroethylene, etc. are suitable for a(3), while hydrophilic resins contain hydrophilic functional groups (e.g. - OH, -8o3H1-CO
OH, -Co, -"1iH2) and must be water-insoluble, such as modified cellulose, polyamide, polynisal, acrylic, epoxy,
Polyurethane resins and mixtures thereof can be used. Crosstalk dispersion to form a coating liquid is performed using the well-known method θ).

This coating liquid is applied onto the above-mentioned porous recording layer and dried to form a hydrophilic slipping layer. For coating, a well-known coating method may be applied.The hydrophilic and hydrophilic properties should allow the image forming material and water to pass through, and prevent background smearing. As a result of investigation, the following requirements were further clarified: First, the composition ratio of solid lubricant particles/resin should be determined based on the image forming material's permeability, coating strength, adhesion to the porous recording layer, and abrasion resistance. However, in order to satisfy all conditions, the solid lubricant/resin composition ratio must be in the range of 2/1 to 29/1 by weight.

Next, regarding the particle size of the particles, if it is too small, the permeability of the image forming material will decrease, and if it is too large, the surface roughness will become too large and the scumming prevention effect will decrease. The range should be 05-10μ. Next, regarding the thickness of the coating film, if it is too thin, it will not be able to adequately cover the surface of the porous recording material underneath, and if it is too thick, the permeability of the image forming material will be reduced. Taking into account that this may occur, the optimum film thickness range must be 2 to 10 μm.

As lipophilic image forming materials that can be applied to the lithographic printing original plate of the present invention, there are stamps 1' using a type rider, handwriting using oil-based ink, transfer using a thermal transfer recording method, paper printing, or electrophotographic transfer.

Here, an example of the method of forming an image on a lithographic printing original plate according to the present invention will be explained in detail with reference to the drawings. Moreover,
The ink ribbon (5) is placed close to the ink ribbon (5), and the ink is transferred into the hydrophilic slipping layer (4) and the porous recording layer (3) using a pressure-contact transfer means using the throat 16) of a wire dot impact printer or typewriter. Transference, infiltration, infiltration image (
7) is formed. This penetration image (7): i. Since the ink penetrates into the hydrophilic slipping layer (4) and the porous recording layer (3) at the same time as it is transferred, there is no need for any subsequent fixing means, and it can last for a long time. It is characterized by its ability to withstand harsh use.

When a lithographic printing master plate with an image formed in this way is attached to a printing machine on the way to the office and printed, the hydrophilic slipping layer contains solid lubricant particles (・), so it is resistant to mechanical wear. Moreover, since the image area is a penetrating image, the printing durability is uncertain, and the dampening water penetrates into both image areas and the hydrophilic lubricating layer and the first layer, the porous recording layer, are wetted. Since it has the ability to hold water in a sufficiently stable manner, it is easy to adjust the amount of water and ink supplied, and it is possible to obtain a large number of stable printed products of good quality without background stains.

Examples of the present invention will be shown below.

<Example 1> On a polyester film (thickness 100μ), 2 parts of powdered silica (manufactured by Mizusawa Kagaku ■/average particle size 2μ), (weight ratio below), polyurethane resin (manufactured by Nippon Polyurethane ■, polyester triol/isonor) A mixed solution consisting of 4 parts of methyl ethyl ketone, 8 parts of methyl ethyl ketone, and 2 parts of toluene was stirred for about 20 minutes using a screw stirring type disperser, and the uniformly dispersed coating liquid was applied using a roll coater. , and dried to form a porous recording layer. The film thickness was 20μ. in addition,
7 parts of powdered talc (average particle size 6μ), 1 part of polyurethane resin
A mixed solution consisting of 1 part, 8 parts of methyl ethyl ketone, and 2 parts of toluene was stirred for about 10 minutes using a screw agitation type disperser, and the coating solution was uniformly dispersed and coated using a roll coater, and dried to form a film with a thickness of 4 μm. A hydrophilic slippery layer was formed. This is used as a master plate for lithographic printing /2.

Next, this lithographic printing original plate was installed in a wire dot printer, and impact printing was performed using a commercially available nylon cloth carbon ribbon to form a clear permeation image on the hydrophilic slipping layer Lυ, thereby preparing a printing plate. Even when the printing plate was rubbed with two fingers immediately after the image was printed, the ink in the image area did not disappear or run.

When I printed this printing plate on the Off-Se-Noto printing machine (Rota Print Off-Se No-Ta), I found that the background was smudged.
・8,000 copies of printed materials were obtained.

<Example 2> 8 parts of calcium carbonate powder (manufactured by Shiroi Calcium ■) and polyester resin (Toyobo T4') were placed on high-quality paper (110 kp).
(manufactured by L) 1 ffi, 02 parts of nitrocellulose (Teisel Co., Ltd.), 15 parts of methyl ethyl ketone, 15 parts of toluene
A coating solution obtained by kneading a mixed solution consisting of 50% by volume in a ball mill for about 4 hours was applied with a roll coater and dried to form a porous recording layer. Furthermore, on top of that 0), 2 parts of boron nitride powder (manufactured by Denki Kagaku Kogyo ■), epoxy JJt resin (Ebico-L 828 / Ebicure H-2 manufactured by Yuka Ciel Epoki 7■)
system) 1 part, mercapto-based silane coupling agent KBM8
A mixed solution consisting of 1 part of 03 (manufactured by Shin-Etsu Chemical), 15 parts of isopropyl, 15 parts of toluene, and 5 parts of toluene was added to
Stir for about 1 hour using a knee stirring type disperser and apply the uniformly dispersed coating liquid using a gravure coater.1. The mixture was dried by heating to form a hydrophilic slipping layer having a thickness of 6 μm. This was placed in a predetermined manner and used as an original plate for lithographic printing.

Next, carnauba wax and carbon wax (weight ratio 4/1) were applied to this planographic printing original plate of 220μ Gra77 paper.
Using a thermal transfer ribbon on which a dry film and a filter ink layer were formed with a thickness of 65/l, transfer recording was performed using a thermal recording head using a thermal recording method, and a clear penetration image was formed. No heat fixing is performed immediately after recording, but this recording surface 2
Even if you rub it hard with your fingers, the ink won't disappear or run.)

When the printing plate was printed using an offset printing machine (Rotaprint Offsenota) K, 5,000 copies of clean printed matter with no blemishes were obtained.

[Brief explanation of drawings]

The drawings show one embodiment of the present invention, and Figure 21 is a diagram showing the configuration of the planographic printing original plate of the present invention, and Figure 2 is an explanatory diagram showing an example of a method for recording an image on the planographic printing original plate. be. 11)...Material plate for lithographic printing i21...Support
Body 13)... Porous recording layer (4)... Hydrophilic slipping layer (5)... Quick ribbon (6)...
Head (7) Penetration image patent applicant Toppan Printing Co., Ltd.

Claims (2)

[Claims] (1) Consisting of an inorganic or organic pigment with a particle size of 0.5 to 5μ and a resin that uniformly disperses and binds the pigment on a support,
After providing a porous recording layer with a pigment/resin composition ratio of 1A to 4/1 in weight ratio to a thickness of 10 to 3,071 mm, a hydrophilic slipping layer of 2 to 1 mm thick is formed on the porous recording layer. An original plate for lithographic printing characterized in that it is provided with a thickness of .tt. (2) The hydrophilic slipping layer is made of a hydrophilic gel [resin] that uniformly disperses and binds solid lubricant particles with a particle size of Q5 to 10 μm, and the composition ratio of particles/resin is 2/1 by weight. ~20/1
A lithographic printing original plate according to claim 1 to claim (1), characterized in that the original plate is provided so that: