JPS61193155A - Manufacture of dry offset printing plate - Google Patents

Abstract

PURPOSE:To obtain an offset plate requiring no dampening water by coating a support with microcapsules contg. a photopolymerizable monomer, imagewise exposing the coated support to harden the exposed capsules, overlaying a base plate having a surface coated with a silicone resin layer on said support, and pressing them to transfer the contents of the unexposed capsules to the base plate. CONSTITUTION:The support is coated with the microcapsules contg. the photopolymerizable monomer, and imagewise exposed to harden the exposed capsules, and the silicone resin layer formed on the base plate is overlaid on the support and pressed to transfer the contents of the unexposed capsules to the base plate, and then, this plate is uniformly exposed. The microcapsules can be controlled in pressure collapsibility by light irradiation, and when the contents are wanted to be taken out, the contents can be released by applying the external force or the like to the capsules to break the outer shells like ordinary capsules.

Description

Detailed Description of the Invention "Industrial Application Field" The present invention relates to a method for producing a so-called dry offset printing plate without using dampening water, and in particular, a method for producing a printing plate using a dry process 11. It is related to.

``Prior art'' Various printing methods are used in the field known as light printing, but offset printing, which is superior in terms of image quality and printing durability, has become widely used. Also. Conventionally, in offset printing, dampening water and oil-based ink are alternately supplied to the plate surface, and the dampening water is applied to the hydrophilic non-image areas.
Printing is performed by supplying ink to the lipophilic image area. This method requires a high level of skill to control dampening water, such as suppressing the flow of dampening water during printing.

Aiming to overcome the above drawbacks, Tokukai Sho! ! -32
Various offset printing plates that do not require dampening water have been proposed in Reference 14 and Japanese Patent Application Laid-open No. 11-10, etc., but most of them involve wet development processing and require large-scale equipment. It has some undesirable points, such as problems such as oxidation and troublesome developer management.

In addition, although it is not related to offset printing plates that do not require dampening water, JP-A-Sho I! published a method using photocuring disk capsules as a method to eliminate the complicated process of wet processing. ---Thing 7! It is disclosed in Publication No. This method involves coating a layer containing photocurable microcapsules, subjecting the coated layer to pattern exposure, applying pressure, and exposing it again to obtain an offset printing plate, and does not involve wet processing. However, this method utilizes the hydrophilicity of the microcapsule wall and the lipophilicity of the photocurable resin, and dampening water is required for printing, and the microcapsule wall needs to be hydrophilic. be. Therefore, there are restrictions in selecting the wall material for the microcapsules. Even if the wall of Maku microcapsules is hydrophilic, if the lipophilic properties of the photocurable resin are similar, dampening water and oil-based ink may mix during printing, making the printed image unclear. Garai.

``Problem to be Solved by the Invention'' Therefore, the problem to be solved is to provide a method for producing a dry offset printing plate in a component process using dry processing without using dampening water.

"Elaborate Means for Solving the Problems" The present invention relates to a method for producing a dry offset printing plate that can solve the above-mentioned problems. A capsule is applied, image exposure is performed on the coated layer surface, and after the exposed part of the capsule is cured, it is overlapped with a substrate having a silicone resin layer on the surface and pressurized, and the contents of the capsule in the unexposed part are transferred to the substrate. This makes it easier to expose the entire surface of the transferred substrate.

The photopolymerizable monomer-containing microcapsules used in the present invention are microcapsules whose pressure rupture can be controlled by light, and when it is desired to expel the contents, pressure can be applied from the outside in the same way as with ordinary microcapsules. The microcapsule wall can be ruptured and the contents released. 17t. When the contents are encapsulated in the microcapsules as they are, the microcapsules are exposed to light, and if necessary, the contents are hardened through heating or other steps.

Therefore, the microcapsules after photocuring are not destroyed by normal pressure, and no release of the contents occurs. Such photosensitive microcapsules are coated on a support, subjected to image exposure, and after curing the capsules in the exposed areas, they are stacked on a substrate having a silicone resin layer on the surface and pressurized to release the contents of the capsules in the unexposed areas. transferred to the substrate. When the image is then transferred and the entire surface of the substrate is exposed to light, the polymerizable monomer is photopolymerized onto the substrate having an oil-repellent silicone resin surface, resulting in an oleophilic image that can be used as a dry offset printing plate. can.

Examples of the photopolymerizable monomer used in the present invention include compounds having an acryloyl group, a methacryloyl group, a vinyl group, an allyl group, an unsaturated polyester group, a vinyloxy group, an acrylamide group, a maleic acid residue, and the like.

The most typical examples include reaction products of polyols, polyamines, amino alcohols, etc. and unsaturated carboxylic acids, and reaction products of acrylates or methacrylates having hydroxyl groups and polyisocyanates.

These monomers usually have absorption in the ultraviolet region below Joanm, so in order to impart photosensitivity to ultraviolet to visible light sources, a photosensitive material that absorbs ultraviolet to visible light and superimposes seven monomers is used. It is desirable to use them together. Examples thereof include those generally known as photopolymerization initiators, such as aromatic ketones, quinone compounds, hexaarylbiimitasole, and the like. In particular, the photopolymerization initiators described in Japanese Patent Application No. 1431 are preferred because of their high sensitivity.

Additionally, an adhesive may be used in combination to strengthen the adhesion of the monomer polymer to the silicone resin layer.

Examples include adhesive silicone resins, vinyl acetate or copolymers thereof, acrylic resins, rubber materials, and the like.

In addition, known thermal polymerization inhibitors, patent application Shozy-/2/L
The components that cause the color-forming reaction described in the specification of No. Jr. can be contained in the microcapsules.

When encapsulating the above ethylenically unsaturated compound, photopolymerization initiator, etc., a solvent can be used in combination.

As the solvent, natural or synthetic oils can be used alone or in combination. Examples of solvents include cottonseed oil, kerosene, aliphatic ketone J aliphatic esters, loughine, naphthenic oils, alkylated biphenyls, alkylated terphenyls, chlorinated paraffins, alkylated naphthalenes, and! -phenyl-7-xylylethane, l-phenyl-/
Examples include diarylethanes such as -D-ethylphenylethane and /,/'-ditolylethane.

Any known encapsulation method can be used to encapsulate these compounds. For example, as a method for manufacturing capsules, US Pat.
0, a method using coacervation found in YSR, British patent Tata 0゜4A4A3, US patent 3.
17,118, U.S. Patent J, A/I.

No. 210, same! , 440. US patent for polymer precipitation method seen in JO Gogo! , 72t.

There is polymerization of glue actant from inside the oil droplet as seen in No. 10 Tei and US Pat. No. 7.7PJ, No. 472.

41, when a method by polymer precipitation and an encapsulation method by polymerization of actant from inside the oil droplet are used.
The effect is great. That is, capsules suitable for use as a photosensitive material having a uniform particle size can be obtained in a short time.

The particle size of the capsules is preferably 20μ or less, particularly 7θμ or less from the viewpoint of handling during storage.

As the support, a plastic film, synthetic paper, metal such as aluminum or iron, paper, or a composite of these can be used.

When coating the support, a protective agent such as a binder starch such as PVA or latex is used. Further, various additives, binders, antioxidants, anti-smearing agents, surfactants, coating methods, usage methods, etc. conventionally used in recording systems are well known, and are disclosed in U.S. Patent λ, 71/ , 37! , Same J, 4! , 73 Haruka, British Patent l.

Ko3ko, Jg7, Tokukai Sho J-04!4! , 0/λ issue, same! θ-10, 11 Ko, 10-/core, 71 Haruka, same! 0-J0.4/! No., U.S. Patent J, IJt, 313, Ir4L4. There are disclosures in JJ/ issues, etc., and those methods can be used.

As a substrate having a silicone resin layer used in the present invention, for example, JP-A-Sho! Kokode No. 30j, JP-A-Sho J-4-4
Here! It is sufficient to form an organopolysiloxane-containing layer on a substrate as described in the 3rd bulletin, and usually an organopolysiloxane having a terminal hydroxyl group is used, a cross-linking agent such as alkoxysilane is present, and the layer is coated and dried. Cross-linking is performed by post-heat treatment to form a silicone resin layer.

Substrates include paper, plastic films, metal sheets, synthetic papers, rubber-like sheets, and composites of these materials.

The thickness of the silicone resin layer is less than ionμ, preferably 0.1.10μ, and the heat treatment temperature is room temperature to 3.
Preferably within a range of 10°C or less! 0,100°C%
More preferably, the temperature is 100 to 0°C.

The specific heat treatment time is 0.1 to 10 minutes, preferably 7 to 3 minutes.
It is 0 minutes.

The method for producing an offset printing plate of the present invention includes exposing a layer containing microcapsules to light using a light source such as a tungsten lamp, a halogen lamp, a xenon lamp, or a mercury lamp, and then forming a layer containing microcapsules and a silicone resin layer. The silicone resin layer may be exposed to light using a light source such as a tungsten lamp, a halogen lamp, a xenon lamp, or a mercury lamp.

"Example" Examples of the present invention will be shown below, but the present invention is not limited thereto.

Example 1 (1) Photosensitive microcapsules were produced as follows.

Trimethylolpro/R triacrylate! 4 to t
C, 4c/-bis(diethylamino)benzophenone o
, zt and Cormel Capto! -Methylthio-/,!
, 4A-thiadiazole 0. ! Dissolve f. Also λ
, J'-bis(0-chloro6 phenyl 1-g, l, z
, z'-tetraphenylbiimidazole1. If 11
Dissolve in methylene chloride and mix with the above monomer, and then mix into the oil phase.

On the other hand, 70% gum arabic aqueous solution 17. If % l co-isobutylene/maleic anhydride aqueous solution lr.

If, distilled water-A, tf mixture to pH 3 with sulfuric acid,!
and further add urea 1. ≦t, resorcinol, ttt-
In addition, the previous oil phase was emulsified and dispersed in this solution. Next, add JA% formalin and add 5f while stirring.
Raise the temperature to c and 1 hour later! Add 2 ft of ammonium thiosulfate aqueous solution, stir for 1 hour while maintaining the temperature at 0°C, and then cool. Then change Na0HVc to CpH to 2. O Toshitomo.

(2) Thus obtained capsule liquid jfVc/1% PVA aqueous solution 1. jJf, distilled water! , 4A7f, -1:: 0. j7f was added to prepare a coating liquid. This was applied to art paper using coating rod #1O1 and dried for 2 minutes at /DO°C to obtain a photosensitive sheet.

(3) An aluminum plate made by applying silicone F3P and JOtj to the surface and drying it after printing the image of the reflective original onto the above-mentioned photosensitive sheet using an exposure device consisting of a /r0W ultra-high pressure mercury lamp, lens, and mirror. Then, the capsules were stacked so that the coating layer side and the silicone resin side were facing each other, and passed through a pressure roller. The unexposed portion of the capsule was destroyed and its contents were transferred.

Then, the entire surface was exposed to light to obtain dry offset printing.

(4) Using the t'L dry offset printing plate thus obtained, a clear image was obtained as a result of printing with waterless lithographic ink (manufactured by Toyo Ink). Also, the printing durability is more than s, ooo sheets.

Claims (1)

[Claims] Microcapsules containing a photopolymerizable monomer are coated on a support, image exposure is performed on the coated layer surface, and after the exposed portions of the capsules are cured, they are stacked with a substrate having a silicone resin layer on the surface and pressurized. A method for producing a dry offset printing plate, which comprises transferring the contents of a capsule in an exposure area onto the substrate and exposing the entire surface of the transferred substrate.