JPS58183298A - Direct drawing type planographic printing base plate - Google Patents

Abstract

PURPOSE:To obtain the hydrophilicity and the water resistance of an image receiving layer and to reduce the irregularity in quality, by providing a specific image receiving layer on a water resistant support. CONSTITUTION:A direct drawing type planographic printing base plate is formed by providing an image receiving layer containing an acrylhydrazide polymer and an inorg. pigment on a water resistant support. As the water resistant support, wet strength high grade paper and one prepared by providing water resistant layer to one surface or both surfaces of the high grade paper are designated. The water resistant layer is formed by coating and drying a resin solution prepared by dissolving alkyd resin or acrylic resin in a solvent.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a planographic printing original plate, and more particularly to a direct-plating planographic printing original plate in which a specific material is applied to an image-receiving layer.

Currently, the planographic printing master plates used in office printing include (1) one with a single layer of markings (th key receiving layer) on the base paper, and (2) a photoconductive layer on the cover. Typical examples include an electrophotographic type with (I!lIglI coral layer) and (3) PB board. Among them, in the master plate mentioned in 1 above, the K to be formed on the printing plate by forming @ on it is KI on the printing layer! ? This is advantageous compared to the other original plates mentioned in 2.3 above because it can be handwritten with 1B ink, type-printed, or xerographically done more easily than K.

By the way, the image-receiving layer in this direct-plated lithographic printing original plate, like that of other types of lithographic printing original plates, is desensitized and then made hydrophilic enough to repel ink during printing with a lithographic printing surface. At the same time, # during printing
11. It must be water resistant enough to withstand the dampening water supplied in return.

In order to satisfy both hydrophilicity and water resistance, conventional direct-plated lithographic printing original plates contain K.

It is known that an image-receiving layer in which a melamine formaldehyde resin is added as a crosslinking agent to an aqueous resin such as polyvinyl alcohol, and an inorganic pigment is further added thereto is provided on a support (U.S. Pat. No. 2,532,865). It is being However, in such original plates, either the hydrophilicity or the water resistance of this layer may be insufficient due to the mixing ratio of the water-soluble resin and the crosslinking agent, or due to slight fluctuations in the drying conditions after the formation of the image-receiving layer. The selection range of conditions for achieving both water resistance at the same time has been narrow, and there has been a tendency for the quality of the products (original planographic printing plates) to vary widely.

An object of the present invention is to provide an original plate for drawing-type lithographic printing, in which the hydrophilicity and water resistance of an image-receiving layer are stably obtained, and the quality of the image-receiving layer is small in variation.

Another object of the present invention is to provide an original plate for drawing-type lithographic printing, which prevents background smearing during printing and improves printing durability, and allows a large number of clear printed matter to be obtained at all times.

The lithographic printing original plate of the present invention has an LDJ image-receiving layer containing an inorganic pigment and a binder as main components on a water-resistant support, and the binder is made of a cross-linked polyacrylic hydrazide. It is characterized by this.

Note that the above-mentioned and later-described "master plate for drawing-type lithographic printing" refers to a method in which an image is directly formed on the surface image-receiving layer of the master plate using oil-based ink, a typewriter, etc., or a dry toner is applied on the image-receiving layer. Alternatively, when a toner image is transferred by a plain paper copying machine using wet toner, after forming a ms from K, the non-image area is desensitized with an etchant (desensitizing liquid 1, etc.) to form a printing plate. This refers to the original plate used to produce printed matter by applying it to an offset printing machine.

As described above, the original plate of the present invention has a configuration in which an image-receiving layer is provided on a water-resistant support. Water-resistant supports used here include (a) moisture-strengthened high-quality paper itself, (high-quality paper with a water-resistant layer on one side or the flesh side,
Examples include (e) a moisture-strengthened high-quality paper with a water-resistant layer provided on one or both sides, and (d) a plastic film. The water-resistant layer here is made by applying a resin bath solution prepared by dissolving alkyd resin, acrylic resin, cellulose acetate, etc. in an appropriate solvent, or applying a ψ~ type emulsion of alkyd resin, acrylic resin, vinyl chloride side, etc. and drying it. formed by Some examples of producing these water-resistant supports are as follows.

Mu-11 Pulp slurry consisting of 30 parts by weight of MBKP and 70 parts by weight of I, BKP was refined by a super refiner to 35 parts by weight.
Add 1.5 parts of cationic colloidal melamine resin (all solid content ratios) to the beaten 6BRK, and then add an appropriate amount of (lilC acid band) to adjust the pH of this slurry.
After adjusting the weight to 5.6, the weight of the Fourdrinier paper machine K was about 7.
A wet-strengthened fine paper of 0 t/d was made. This is used as a water-resistant support.

Mu-2) Pulp slurry consisting of 40 parts by weight of NBKP and 60 parts by weight of LBKP was reduced to 38@8 using a super refiner.
Add 1 part of rosin (all solid content ratios) to the RK beaten product, add an appropriate amount of sulfuric acid, adjust the pH of this slurry to 6.5 K, and then dry it on a fourdrinier paper machine K. A high quality paper with a length of about 80 f/d was obtained. Apply 451s O/V type emulsion (Hytaloid 8011, manufactured by Hitachi Chemical Co., Ltd.) of acrylic m fat to both sides of this high-quality paper.
A water-resistant support was prepared by drying and forming a water-resistant layer with an adhesion of 10 t/*''.

A-3) On both sides of the wet-strengthened high-quality paper obtained in A-1, a 48-inch O/W type emulsion of alkyd resin (phthalkyd W7) was applied.
40, Hitachi Chemical Co., Ltd. 11i, was applied and dried to form a water-resistant layer of 12 f/wl.
A water-resistant support was created.

A-4) A polypropylene film with a thickness of 80 μm is used as a water-resistant support.

A-5) Synthetic paper mainly composed of polypropylene and having a thickness of 90 μm is used as a water-resistant support.

A-6) A polyester film with a thickness of 60 pm is used as a water-resistant support.

A-7) A polyester film with a thickness of 70 ptfm and matted on both sides is used as a water-resistant support.

Mu-8) 50 parts by weight of rutile If titanium oxide on both sides of the Mu-6 above,
48% of alkyd resin. /W-type Emulsion Symphony (manufactured by Hitachi Chemical, 7 Talkyd 74o) 100111 [tM] and 60 parts by weight of water were applied and dried to give a total of approximately 8 parts by weight each.
A 17d pigeon is provided and then calendered and used as a water-resistant support.

The appropriate ratio of the pigment and the binder constituting the image-receiving layer is 1 to 5111 parts by weight of the pigment to 1 part by weight of the binder. The pigments (inorganic pigments) used here are not particularly limited, but include clay, calcium carbonate, Merck, zinc oxide, titanium oxide, and more! iron oxide, magnesium carbonate,
Examples include barium carbonate, barium chloride, lithopone, silica, and aluminum oxide. These pigments may be used alone or in combination of two or more.

The polyacrylic hydrazide according to the present invention retains hydrophilicity and has water resistance by reacting with a crosslinking agent such as glyoxal.

The ratio of polyacrylic hydrazide and crosslinking agent is 10% by weight.
0:5 to 10G:5G is preferred.

The image-receiving layer is preferably coated to a thickness of 51/d to 30 f/d.

In addition, a water-resistant intermediate layer is provided between the substrate (water-resistant support) and the image-receiving layer to further improve printing durability.
Alternatively, a back coat layer may be provided on the back surface of the substrate to prevent curling. .

The intermediate layer (0.5-10μ steel thickness) is acrylic resin,
8BR% MBR% 11BR, emulsion type resin such as vinyl acetate-ethylene copolymer, or S* fat that can be used as a bath agent such as epoxy resin, polyvinyl butyral, acrylic resin, polyvinyl acetate, polyvinyl chloride, etc. alone. Or 2 or more strokes are used together. Also, a suitable amount of pigment may be added to this intermediate layer.

The back coat layer (0.5 to 30μ steel thickness) includes starch or starch derivatives, OMO% Mmc throat @seha derivatives, polyvinyl alcohol, casein, vinyl acetate-crotonic acid copolymer, polyacrylic acid. Water-soluble resin such as ammonium or acrylic resin, 81R% MBR
.

Emulsion type resins such as vinyl acetate-ethylene copolymers are used alone or in combination with two or more pigments and other additives. Further, an appropriate amount of pigment may be added to this pack coat layer, and furthermore, the back coat layer may be of the same composition as the intermediate layer or the image receiving layer,
A stacked type of these may also be used.

As described above, since the lithographic printing original plate of the present invention uses a specific substance as a binder in the image-receiving layer, an image-receiving layer having good water resistance and hydrophilicity is formed.

Furthermore, the image-receiving layer of the present invention has strong resistance to organic solvents such as hydrocarbons, alcohols, ketones, ethers, and esters, so it can be directly applied with an oil-based writing instrument, or an oil-based toner image can be transferred using a plain paper copying machine. Even if you do,
1IIIi image receiving 1m does not melt or change in quality, so a master made from this lithographic printing original plate can produce many clear prints.

Next, examples will be shown. Note that all parts are parts by weight.

Example 1 Polyacrylic hydrazide (M manufactured by Nippon Hydrazide Co., Ltd.)
L) Add glyoxal 2f to a solution of 10f and water 90fO, then add clay 20f and zinc oxide 10F, disperse in a ball mill for 4 hours, apply this to one side of the support of the above Mo-1), and add 120@O Dry for 3 minutes with 16t
An original plate for lithographic printing was prepared by forming an image-receiving layer of /m.

This original plate was transferred to a conventional copying machine (FT-6) using a dry developer.
400 (manufactured by Ricoh) and then etched it with a commercially available desensitizing solution (Ricoh Fax Etch Solution (Ricoh M) K), the non-IdIi image areas blended with the desensitizing solution and had the desired desensitization properties. Admitted. The circular printing plate made in this way is then printed on a lithographic printing machine (MuP-2600).
When printed using Ricoh (manufactured by Ricoh) K, more than 500 good quality prints with no background smear were obtained. In addition, when the drying conditions during the formation of the th image-receiving layer were varied from 120"02 minutes to 10 minutes to prepare a lithographic printing original plate, this was printed on the #i plate in the same manner as above, and the results were similarly good. 1 and 9.

Example 2 A printing original plate was prepared in the same manner as in Example 1 except that 10 tf of anatase-type titanium oxide and 10 tf of silica were used instead of clay in Example I, and a printing plate was prepared using a commercially available typewriter (
When drawing was performed using IJTTKRA3910 (manufactured by Oriperati) and subjected to the same desensitizing treatment and printing as in Example 1, more than 800 clear prints without background smear were obtained.

Applicant: Ajishiki Company Ricoh

Claims (1)

[Claims] A one-stroke lithographic printing original plate, characterized in that an ij image-receiving layer containing an acrylic hydrazide polymer and an inorganic pigment is provided on a water-resistant support.