JPS58199153A - Preparation of offset press plate - Google Patents

Abstract

PURPOSE:To obtain an offset press plate capable of being photoengraved by a simple apparatus without necessitating a light source and development treatment, by a method wherein a specific wax-containing layer is provided on a water resistant support and the surface thereof is subjected to thermal printing by thermal head. CONSTITUTION:On a water resistant support such as paper, a film or synthetic paper subjected to water resistance imparting treatment, a layer containing wax with a m.p. of 60-180 deg.C and a particle size of 0.1-10mum, a hydrophilic binder and a pigment is provided and the surface thereof is printed under heating by a thermal head to obtain an image part. The wax of the thermally printed part is melted and the surface of a press plate becomes oleophilic and comes to an ink receivable surface. On the other hand, because the wax of a non-image part is covered with the hydrophilic binder, said non-image part shows hydrophilicity and functions as the water holding surface of damping water in printing.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing offset printing plates. More specifically, the present invention relates to an offset printing plate manufacturing method using a thermal printing device that does not require a light source or development process.

Methods for obtaining offset printing plates used in offset printing include #1 (1) direct plating method, (2) negative and positive base method, and (3)
) camera plate making method, and (4) direct plate making method, but the direct plate making method, which can be completed in a few tens of seconds from setting the block to starting printing, is the most popular method due to its low cost. These O methods are widely used for small in-house printing and light printing.The direct plate making method is the KFi Beriris method, the silver halide photography method represented by the Silver one method, and the electrophotography method represented by the Electrofax wet method. The direct plate making machine used has been commercialized.

However, with the direct plate making method, the manufacturing machine itself is large because it involves forming a light-filled sickle, developing it, and handling the printing plate.Also, there are problems with using it in an office, such as getting your hands dirty when handling the developer. was there. Therefore, as a result of intensive research, the present inventors have discovered a method of directly obtaining printing plates using a thermal printer or thermal facsimile machine that is maintenance-free, relatively simple, and compact.

That is, a layer containing wax with a melting point of 60 to 180°C and a particle size of 0.1 to 10 microns is provided on a waterproof support such as waterproof paper, film, synthetic paper, metallized paper, or synthetic resin laminated paper. The present invention provides a method for obtaining an offset printing plate that does not require a light source or development process and can be made using a simple device by thermally printing this surface using a thermal head.

In the offset printing plate manufacturing method of the present invention, a layer containing a wax with a melting point of 60 to 180°C and a particle size of 0.1 to 10 <Kron, a hydrophilic binder, and a pigment is provided on a water-resistant support, and this surface is thermally coated. It is characterized by thermal printing with a head and by thermally melting the wax in the printed area to make it oleophilic and obtain an offset printing plate. Furthermore, if a finely ground leuco dye and a finely ground developer are added to the wax-containing layer, the printed area will develop color due to the reaction between the leuco dye and the developer, producing a positive image on the printing plate. It is also possible to have it come out.

The waxes used in the present invention include paraffins, polyolefins, microwaxes with melting points of 6 to 120°C, and fatty acid waxes with melting points of 60 to 180°C. Examples of the former wax include paraffin wax having a melting point of 60 to 73°C, microwax having a melting point (or softening point) of 60 to 120°C, or polyolefin wax such as polyethylene wax or polypropylene wax. It will be done. This polyethylene wax or polypropylene wax usually has a molecular weight of 100.
0 to 100,008 degrees, i.e., known as polyolefin waxes, these polyolefins are usually produced by high-pressure and low-pressure polymerization processes (i.e., low-density and low-density polyolefins), or high-molecular-weight polyolefins. It is caused by thermal decomposition of polyolefin. Furthermore, in order to facilitate emulsification, these waxes can be oxidized to introduce polar groups such as hydroxyl groups, ester groups, carboxyl groups, aldehyde groups, and peroxide groups. Further, in order to lower the softening point and improve confectionery making properties, it is also possible to use these waxes in combination. The latter include stearamide, lyrunamide, laurylamide, myristylamide, hydrogenated tallow acid amide, palmitamide, oleic acid amide, rice sugar fatty acid amide, coconut fatty acid and t or methylolated products of these fatty acid amides, methylene bis stearamide,
Examples include ethylene bisstearamide, and a combination of these is also possible.Also, the wax is dispersed in a hydrophilic binder, and these dispersed particles are crushed by a grinder such as a ball mill. It is preferable to grind the particles to a particle size of 0.1 to 10 microns. Further, waxes may be dispersed as described above, or may be added in the form of an emulsion using an emulsifier.

As the hydrophilic binder, water-soluble resins known in the art are suitable; specifically, polyvinyl alcohol, methyl cellulose, hydroxyethyl cellulose, gum arabic, carboxymethyl cellulose, fIA powder,
Gelatin, casein, polyvinylpyrrolidone, styrene anhydride V4 M copolymer, methyl vinyl ether maleic anhydride copolymer, polyacrylic UK salt, and polyacrylic acid copolymer are used. Also, latexes such as styrene getadiene latex can also be used.

Further, if necessary, melamine formaldehyde, urea formaldehyde, glyoxal, or a crosslinking agent may be added to impart water resistance.

Clay, zinc oxide, calcium carbonate, aluminum oxide, silica, *g-barium, etc. are used as materials.

Next, examples of leuco dyes used to produce a positive image on the printing plate include crystal violet lactone, 3-
Dieterium-7-chlorofluorane, 3-diethylamino-6-methyl-7-/rolofluorane, 2-(M
-7enyl-methylamino)-5-(M-1'-)
Lilloo-ethyl)amino-fluorane, 3-(N,
M-diethylamino)-5-methyl-7-(M,M-
dibenzylamino)-fluorane, malachite green lactone, 3,3-bis(l-ethyl-2-methylindol-3-yl)-7thalide, 3-diethylamino-
6-Methyl-7-anilino-fluorane, 2-7nilino-3-methyl-6-(M-ethyl-P-toluidino)fluoran, 3-(M-cycloheΦsil-methylamino)-6-methyl- Colorless or slightly pale lactones, sultones, such as 7-anilinofluorane, 3-pyrrolidino-6-methyl-7-7nilinoflu, 3-piperidino-6-methyl-7-anilinofluorane, Compounds include 2cutam and spiropyran.

As a color developer, it has a melting point of 60°C which can color leuco dye when heated.
The above phenolic compounds, especially phenolic compounds having two or more hydroxyl groups in one molecule, are preferred, specifically 4.4'-iso10pylidene diphenol, 4.4
Examples include '-isopropylidene bis(2-tert-butylphenol x4-phenylphenol), 4.4'-cyclohexylidene diphenol, 4.4'-cyclohexylitine bis(2-methylphenol), novolac wrinkled phenol resin, and the like.

When adding a leuco dye and a color developer to a layer containing wax, the leuco dye and developer are each separately placed in a medium containing an appropriate amount of water-soluble resin using a pulverizer such as a ball builder. It is necessary to crush and disperse the particles to 10 microns or less.

The water-resistant support used in the present invention is generally made of high-quality water-resistant paper, but PIC? Films such as, synthetic paper, vapor-deposited paper, synthetic resin laminated paper, etc. can also be used.

The offset printing plate of the present invention can be manufactured by the following method, but the present invention is not limited thereto. Melting point 60-1
K1. on a water-resistant support, which is a coating liquid at 80° C. and containing a wax and pigment having a particle size of 1 to 10 microns dispersed in a hydrophilic binder. ! Dry high.

The coated surface may be calendered if necessary.

The obtained offset printing plate precursor is thermally printed using a thermal printer (used as a word processor terminal) or a thermal printing wax device such as a thermal facsimile machine to obtain a line portion. The wax in the thermally printed area melts (7) and becomes lipophilic on the plate surface, making it receptive to ink.On the other hand, the wax in the non-printing area is covered with a hydrophilic binder, so it exhibits hydrophilic properties and is used to dehumidify printing. Acts as a water-retaining surface.If crushed leuco dye and crushed color developer are added to the wax-containing layer, the leuco dye and color developer react with each other during thermal printing, resulting in a positive color in the lined area. 0 appears on the printing plate as an image. Therefore, it is possible to easily modify the layout of the Iwaobe.

In order to further improve the printing durability of the offset printing plates obtained in this way, the non-image areas on the plate surface are subjected to a 1m hydrophilic treatment or the image areas are sometimes subjected to a 0-hydrophilic treatment. Kli! The processing liquid used is generally gum arabic,
Hydrophilic resins such as polyvinyl pyrrolide, phosphates, aluminum aluminium compounds, and at least one of acids (organic or inorganic acids), and hyferocyan compounds or ferricyan compounds. Treatment liquids used for 0 lipophilic treatment include:
For example, there are those mainly composed of polymers having hydrophilic groups or metal salts thereof.

Next, examples will be described to further specifically explain the present invention.

Implementation H1 Offset by applying the following composition of paint to one side of the high-quality paper 1401/d, which is mainly made of long-fiber pulp and has excellent size, water resistance, and smoothness, so that the electricity after drying is 817 wl. O from which the printing plate precursor was obtained (Paint formulation) 20 parts of sauce 100 parts of tivolivinyl alcohol aqueous solution 1 part of microwax emulsion (solid content: 40, starvation point: 80, average particle size: 3 microns) 50 parts: 80 thymelamine-formaldehyde resin Aqueous solution: 4 parts Water: 20 parts Next, the above-mentioned offset printing plate precursor was thermally printed using a thermal printer used as a terminal of a Watts processor to obtain a printing plate. This plate was immediately printed on an offset press.

Example 2 On one side of the same high-quality paper as in Example 1, blood of the following composition was applied so that the weight after drying was 1217 d, and further calendering was performed to obtain an offset printing plate precursor. ) Clay 20 parts 10% polyvinyl alcohol 100s stearic acid a!
Ide dispersion (solid content 3056, melting point 100 - average particle size 4 microns)
30 parts 50s ethylene urea aqueous solution 5 parts 3-diethylamino-6-methyl-7-anilinol second dispersion (solid content 40%, average particle size 3 microns) 5 parts bisphenol pentadispersion (solid content 301 g, (average particle size: 3 microns) 25 parts water 20 parts Next, the above offset printing plate precursor was thermally printed using a heat-sensitive facsimile to obtain an offset printing plate. At this time, a positive image appears on the printing plate due to the color development of the leuco dye and developer. This plate could be printed immediately on an offset printing machine.

Claims (1)

[Claims] (1) Melting point 60-180″ctP on a water-resistant support
A layer containing wax with a particle size of 0.1 to 10 microns is
This is an offset printing plate manufacturing method that allows thermal printing of this surface using a thermal head. (2) The water-resistant support is water-resistant paper, film, synthetic paper, metallized paper, or synthetic resin lamickey paper.
A method for producing an offset printing plate according to claim 1. (3) The offset printing plate manufacturing method according to claim 1m, in which the wax-containing layer contains a hydrophilic binder and a pigment (4) The wax-containing layer contains a leuco dye and a color developer A method for producing an offset printing plate according to claim 1. (5) The offset printing plate manufacturing island according to claim 3J or claim 4, which is subjected to hydrophilic release and/or lipophilic treatment after thermal printing.