JPS61163343A - Waterless lithographic printing plate - Google Patents

Abstract

PURPOSE:To improve printing resistance and scratching strength by laminating and disposing successively a primer layer, photosensitive layer and silicon rubber layer on a substrate, using a quinonediazide compd. as the constituting component for the photosensitive layer and incorporating a specific ratio of a rubber component into the primer layer. CONSTITUTION:The primer layer, photosensitive layer and silicon rubber layer are laminated and disposed in this order on the substrate. The quinonediazide compd. is used for the constituting component of the photosensitive layer and the rubber component, for example, polyurethane is incorporated at about 30wt% into the primer layer. The photosensitive layer consists preferably of the photostrippable photosensitive layer formed by crosslinking a quinonediazide by a multifunctional compd. The convenience is better as the photosensitive layer is thinner and the result obtd is better as the primer layer is thicker. The effect is therefore higher as the ratio between the film thickness of the photosensitive layer and the thickness of the primer layer is smaller, Said ratio is preferably set at <=1.0, more preferably <=0.5. The waterless lithographic printing plate having the excellent scratching strength and printing resistance is obtd. by such constitution.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a waterless planographic printing plate.

In particular, it relates to a waterless lithographic printing plate that has excellent printing durability and scratch strength.

[Prior art]

As a photosensitive compound for a waterless lithographic printing plate, an ester compound of 0-naphthoquinonediazide sulfonic acid and a phenol novolac resin is excellent in terms of photosensitive characteristics, storage stability, etc., and several proposals have been made in the past.

For example, Japanese Patent Application Laid-Open No. 55-59466 discloses that it is lined with an aluminum plate. A waterless lithographic printing plate is disclosed in which a silicone rubber layer is provided on a photoreleasable photosensitive layer made of a quinonediazide compound via an adhesive layer. In addition, JP-A-56
Publication No. 80046 discloses a waterless lithographic plate in which a silicone rubber layer is provided on a photosensitive layer made of a partially esterified product of naphthoquinone-1,2-diazide-5-sulfonic acid chloride and a phenol novolac resin crosslinked with a polyfunctional incyanate. A printed version is disclosed.

[Problem that the invention seeks to solve]

These conventional waterless lithographic printing plates.

There are the following problems in the plate making and printing process.

(1) Non-image areas are easily scratched during development or handling of printing plates.

(2) Printing durability is insufficient. For normal printing, 40.
When the OO0 sheet is printed repeatedly, fine dot-like defects occur in the non-image areas, and the surface of the silicone rubber layer partially picks up ink.

Initially, these problems were thought to be due to the inherently weak strength of the silicone rubber layer.

As we proceeded with the investigation, we found out what was the cause of the above problem.

It turns out that this is because the photosensitive layer is hard and brittle.

If the photosensitive layer is hard and brittle, scratching the plate surface with a hard object such as a sapphire needle will concentrate stress at the interface between the photosensitive layer and the silicone rubber layer, making it easy for only the silicone rubber layer to peel off. Also, during printing, we can reduce the impact force during printing.
The photosensitive layer is not completely relaxed and the silicone rubber layer falls off from the interface between the silicone rubber layer and the photosensitive layer.

For these reasons, various attempts have been made to soften the photosensitive layer. - For example, a method of softening the photosensitive layer by adding a binder polymer or a plasticizer to the photosensitive layer (
(Japanese Patent Application No. 58-73462) or a method using a quinone azide compound synthesized from a Kash-modified novolak resin in the photosensitive layer (Japanese Patent Application No. 129251-1982).

Regarding the former, adding polymers and plasticizers to the extent that they improve printing durability and scratch strength results in a loss of image characteristics, and the current situation is that satisfactory results have not yet been obtained. . Regarding the latter, although we have achieved some success, it is still difficult to say that its effects are sufficient.

An object of the present invention is to eliminate the above-mentioned drawbacks of the prior art and to provide a waterless lithographic printing plate that has excellent printing durability and scratch strength.

[Means for solving problems]

The present invention provides a waterless lithographic printing plate comprising a primer layer, a photosensitive layer and a silicone rubber layer laminated in this order on a substrate, wherein the photosensitive layer contains a quinone diazide compound as a constituent component, and the primer layer contains a rubber component of 30% by weight. The present invention relates to a waterless lithographic printing plate characterized by comprising the following.

The quinonediazide compound used in the photosensitive layer of the present invention is 9
For example, normal positive type PS version, Wipon version.

Refers to quinonediazides used in photoresists, etc. Specific compounds include 1, for example, benzoquinone-1,2-diazide-4- or -5-sulfonate ester with polyhydroxyphenyl, naphthoquinone-1
, ester of 2-diazide-4- or -5-sulfonic acid and pyrogallolacetone resin, naphthoquinone-1,
Esters of 2-diazide-4 or -5-sulfonic acid and phenol formaldehyde novolac resins or cashew-modified novolak resins may be mentioned. In particular, as a photosensitive layer preferably used in the present invention, JP-A-56-
Examples include a light-peelable photosensitive layer in which quinone diazides are crosslinked with a polyfunctional compound, as proposed in Japanese Patent No. 80046.

As a quinonediazide compound in the present invention.

Particularly preferred is a partially esterified product of naphthoquinone-1,2-diazide-5-sulfonic acid and phenol formaldehyde novolak resin.

It is also possible to add other components such as polymers and plasticizers to the photosensitive layer for the purpose of improving coating film forming properties and adhesion.

The composition for forming the above photosensitive layer is prepared by dissolving it in a suitable organic solvent (eg, dioxane, tetrahydrofuran, cellosolve, cellosolve acetate, etc.).

The thickness of the photosensitive layer is 0.1 to 100μ, more preferably 0.1μ to 100μ.
5-20μ is selected. If it is too thin, pinholes are likely to occur, while if it is too thick, it is economically disadvantageous.

The silicone rubber layer used in the present invention usually has as a main component a linear organic polysiloxane having a molecular weight of several thousand to several hundred thousand and having the following repeating units.

Here, n is an integer of 2 or more, R is an alkyl group, alkenyl group, or phenyl group having 1 to 10 carbon atoms, and 6
Preferably, 0 or more groups are methyl groups. Such linear organopolysiloxane.

It is sparsely crosslinked to form silicone rubber. Examples of crosslinking agents include acetoxysilane, ketoxime silane, and alkoxy 7-lane, which are used in so-called room temperature (low temperature) curing silicone rubber.

In combination with aminosilane, amidosilane, etc. 9, which is usually a linear organic polysiloxane with a hydroxyl group at the end, 7 IJ cone rubber of the acetic acid-removed type, oxime-eliminated type, alcoholicated type, deamined type, deamidated type, etc. Become. Generally, a small amount of an organic tin compound or the like is further added as a catalyst to these silicone rubbers.

The thickness of the silicone rubber layer is approximately 0.5-100μ.

Preferably, the thickness is about 0.5 to 30μ; if it is too thin, problems may occur in terms of printing durability and ink repellency; if it is too thick, it is not only economically disadvantageous; It becomes difficult to remove the silicone rubber layer during development, resulting in a decrease in image reproducibility.

In the waterless lithographic printing original plate of the present invention, adhesion between the photosensitive layer and the silicone rubber layer is very important for basic plate performance such as image reproducibility and ITPI printability. An adhesive layer is provided or an adhesive component is added to each layer. In particular, for adhesion between the photosensitive layer and the silicone rubber layer, a known silicone primer, silane coupling agent, or titanate coupling agent layer may be provided between the eyebrows, or a silicone primer, silane coupling agent, or titanate coupling agent layer may be provided on the silicone rubber layer or photosensitive layer. It is effective to add a titanate coupling agent.

The primer layer used in the present invention contains a rubber component of 50% by weight or more, more preferably 50% by weight or more. As a material for rubber components.

Examples include, but are not limited to, the following: Natural rubber, polybutadiene, styrene-butadiene copolymer, 2) IJ A/rubber, acrylic rubber, butyl rubber, polyurethane.

polyester elastomer, polyamide elastomer,
polyether ester amitoelas) -r +.

Examples include polyvinyl butyral, and particularly preferred is polyurethane. As for rubber hardness.

It is preferable that the hardness is 95 or less when measured using a spring-type hardness tester A-type tester specified in JIS K6301-1975. If the primer layer contains more than 95, the effect of improving #4 printability and scratch strength is small. These rubber components may be used alone or in combination of two or more. Furthermore, these rubber components are generally used after being cured with thermosetting resins such as epoxy resins, urea resins, phenol resins, and melamine resins, polyfunctional incyanate compounds, and the like. Furthermore, there is no limitation to the addition of white pigments or yellow pigments such as titanium oxide or calcium carbonate for the purpose of preventing halation from the substrate or improving plate inspection properties.

The thicker the primer layer, the greater the effect of mitigating the impact force during printing, but it becomes disadvantageous in terms of coatability and economical efficiency, and is from 0.57μ to 50μ.

More preferably, it is in the range of 1μ to 20P. From the viewpoint of printing durability and scratch strength, the thinner the photosensitive layer is, the better the thickness, and the thicker the primer layer, the better. Therefore, the smaller the ratio between the photosensitive layer thickness and the primer layer thickness, the more effective it is, and it is usually desirable to set the ratio to 1.0 or less, more preferably 0.5 or less.

The substrate used in the present invention must be flexible enough to be set in a normal lithographic printing machine and capable of withstanding the load applied during printing. Typical examples include metal plates such as aluminum, copper, zinc, and steel, plastic films or sheets such as polyethylene terephthalate and polypropylene, coated paper, and composites thereof.

For the purpose of protecting the silicone rubber layer forming the surface of the waterless lithographic printing plate constructed as described above, a thin protective film treated with a blank or uneven surface may be laminated on the surface of the silicone rubber layer. .

〔Example〕

The present invention will be explained in more detail with reference to Examples below. In addition, although the results of the scratch strength test are shown in this text, the test method is a continuous load type scratch strength tester (TYPE!-HBIDO).
N-18), use a sapphire needle with an R element of 0,1-
Scan at cm/min and scratch the non-image area of the printing plate while applying continuous load. The scratched printing plate is printed using a flatbed proofing machine, and the load at the part where the ink is receptive is measured. This means that a printing plate with a large load that causes ink receptivity has excellent scratch strength. In addition, the subprinting test method in Section 9 was conducted under the following forced conditions, and the number of prints where stains due to damage to the plate surface appeared on the printed matter was recorded.

Printing conditions Printing machine: Hamada Star 700 direct printing modified machine Printing pressure: Underlay 500μ Ink: Osaka Ink "OPI Process" Example 1
~6. Comparative Examples 1 to 4 A primer layer having the composition shown in Table 1 was coated on an aluminum plate with a thickness of 0.2 van using a bar coater,
Heat treatment was performed at 250°C for 6 minutes.

Next, a photosensitive layer having the following composition was applied onto each primer layer using a bar coater, and the photosensitive layer was coated in hot air at 110°0.
A photosensitive layer having a thickness of 2 μm was provided by drying for 1 minute.

(1) Naphthoquinone-1,2-diazide-5-sulfonic acid ester (degree of esterification: 45%) of phenol novolak resin (Sumilite Resin PR5025', manufactured by Sumitomo Duress).

100 parts by weight (2) 20 parts by weight of 4,4'-diphenylmethane diisocyanate (3) 0.2 parts by weight of dibutyltin dilaurate Then, on this photosensitive layer, a silicone rubber layer having the following composition was coated with a bar coater, and then 120℃.

A silicone rubber layer having a thickness of 2 μm was provided by heating and curing for 3 minutes at a dew point of 30°0.

(1) Polydimethylsiloxane (molecular weight approximately 25.0
00, terminal hydroxyl group) 100 parts by weight (2)
Vinyltri(methylethylketoxime)silane
8 parts by weight (3) Dibutyltin diacetate 0.1 parts by weight (4) γ-
0.5 parts by weight of aminopropyltrimethoxysilane The thus prepared laminate was laminated with a 10 micron thick polypropylene film (manufactured by Bundle) using a calendar roller to obtain a printing plate. Ta.

Iwasaki Electric's metal halide lamp "Idol Fin 2"
000J, and image exposure was carried out for 60 seconds with a UV meter (Oak Seisakusho Light Measure Type UV402A). Next, the 1 trepan” was peeled off and the pretreatment liquid (
After immersing it in a developer solution (100 parts of polypropylene glycol with a molecular weight of 400, 5 parts of monoethanolamine, 5 parts of monoethanolamine) for 1 minute, using a nylon brush,
When the photosensitive layer was developed in the exposed area, the silicone rubber layer peeled off, forming an image area in which the photosensitive layer was exposed.

A printing plate was obtained in which a non-image area was formed in which the silicone rubber layer remained in the non-exposed area.

The results of the scratch strength test and forced printing durability test of the printing plates obtained here are summarized in Table 1. As shown in Examples 1 to 6, when a primer containing 500 parts by weight or more of a rubber component was used in the primer layer, compared to the case where the rubber component was not included as in Comparative Examples 1 to 4.

The effect of improving scratch strength and printing durability is remarkable. Also.

As for the film thickness of the primer layer, the thicker the better, but if the film thickness ratio of the photosensitive layer and the primer layer is set to 1.0 or less, the effect of improving scratch strength and printing durability can be recognized.

〔Effect of the invention〕

According to the waterless planographic printing plate of the present invention, the following effects are achieved.

(1) Scratches during development and handling of printing plates are reduced.

(2) Printing durability is improved.

Patent applicant Higashi Shikaisha Ltd. -'417-

Claims (3)

[Claims] (1) In a waterless planographic printing plate formed by laminating a primer layer, a photosensitive layer, and a silicone rubber layer in this order on a substrate, the photosensitive layer contains a quinone diazide compound as a constituent component, and the primer layer contains a rubber component of 30% by weight. A waterless lithographic printing plate characterized by comprising the above. (2) The waterless lithographic printing plate according to claim 1, wherein the photosensitive layer is a photoreleasable photosensitive layer. (3) The waterless lithographic printing plate according to claim 1, wherein the rubber component is polyurethane.