JPS6356657A - Original plate for waterless lithographic printing plate - Google Patents

Abstract

PURPOSE:To increase the adhesive power between a photosensitive layer and silicone rubber layer and to improve the stability of the adhesive power with age by adhering the photosensitive layer and the silicone rubber layer by a specific silicon compd. CONSTITUTION:The photosensitive layer contg. a quinonediazide compd. and the silicone rubber layer are laminated in this order on a base consisting of an aluminum plate, etc., and the two layers are adhered by >=1 kinds of the silicon compds. expressed by the formulas I, II and III. The compd. may be added to the photosensitive layer or rubber layer and may be provided as an adhesive layer between the two layers. In the formula, R<1>, R<2>, R<5> denote an alkyl of 1-15C, aryl of 6-10C; R3, R4, R6 denote an alkyl of 1-15C, alkoxy, etc.; A1, A2 denote an org. group of 1-10C having an amino group; l, m denote 0-3, n, p denote 0-4, n+p>=1, l+m+n+p=4; s, t, u denote 2-5. The scratching resistance and solvent resistance of the rubber layer in the unexposed part and the printing performance of the plate are thereby improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a waterless lithographic printing plate, and particularly to a waterless lithographic printing plate with improved adhesion between a photosensitive layer and a silicone rubber layer.

[Conventional technology]

Various printing plates have been proposed that use silicone rubber as an ink repellent layer and perform planographic printing without using dampening water.

Among these, for example, JP-A-55-57 is used as a waterless lithographic printing plate for negative working, in which a silicone rubber layer is coated on a photosensitive layer lined with a support.
Japanese Patent No. 466 proposes a lithographic printing plate in which a silicone rubber layer is provided on a photodegradable photosensitive layer made of quinonediazide and backed by a support. In addition, JP-A-56
Japanese Patent No. 80046 discloses a presensitized lithographic printing plate comprising a silicone rubber layer provided on a photoreleasable photosensitive layer backed by a support.

However, these conventional waterless lithographic printing plates have the following problems in plate making and printing processes.

(1) Due to insufficient adhesion between the photosensitive layer and the silicone rubber layer, the silicone rubber layer in unexposed areas tends to peel off during development.

(2) During printing, non-image areas are easily scratched, and printing durability is insufficient.

Initially, it was thought that these problems were due to the weak strength of the silicone rubber layer, but as the study progressed, it became clear that the cause of the above problems was the poor adhesion between the photosensitive layer and the silicone rubber layer. It turned out to be insufficient.

For these reasons, attempts have been made to improve the adhesive strength between the photosensitive layer and the silicone rubber layer. For example, a method of mixing aminoalkylsilane, or another silane coupling agent, and a silicone primer in a silicone rubber layer (JP-A-49-86103, JP-A-49-77702, JP-A-55-110249), etc. It is. but,
When these adhesive components are added to the silicone rubber layer, the adhesion between the photosensitive layer and the silicone rubber layer immediately after manufacture is certainly improved. This has the disadvantage that the silicone rubber layer surface tends to be easily scratched during development as it decreases over time.

[Problem that the invention seeks to solve]

As a result of intensive studies to solve these problems, the present inventors found that a silicon compound having an amino group with a specific structure
The inventors have discovered that the adhesive force between the photosensitive layer and the silicone rubber layer can be improved and that the adhesive force does not deteriorate over time, and the present invention has been achieved.

Therefore, an object of the present invention is to provide a waterless lithographic printing plate which solves the above-mentioned problems of the prior art, improves the adhesive strength between the photosensitive layer and the silicone rubber layer, and prevents the adhesive strength from changing over time. It is.

[Means for solving problems]

That is, the present invention provides a waterless planographic plate comprising a support, a photosensitive layer containing a quinonediazide compound, and a silicone rubber layer laminated in this order, wherein the photosensitive layer and the silicone rubber layer have the following general formulas (I) to (I). (Here, R1, R2, and R5 are an alkyl group having 1 to 15 carbon atoms, an aryl group having 6 to 10 carbon atoms, and an aralkyl group.
3, R4, Re is an alkyl group or alkoxy group having 1 to 15 carbon atoms, or an aryl group or aryloxy group having 6 to 10 carbon atoms. A1. A2 has 1 to 10 carbon atoms and has an amino group
organic group. fire.

m is an integer of 0 to 3, n and p are integers of 0 to 4, n0p≧L, Q+m+n+p=4°s, t and u are integers of 2 to 5. The present invention relates to a waterless lithographic plate characterized in that it is bonded with at least one silicon compound shown in the following.

The silicon compound used in the present invention has an organic group having an amine group bonded to a silicon atom via an oxygen atom, and 5
It has two or more iOC bonds and has the general formulas (I) to (II) shown above, and these are used alone or in combination with 91.

The alkyl group, aryl group, aralkyl group, aryloxy group, and alkoxy group of the silicon compound used in the present invention are not particularly limited, but those with a simple structure are preferred from the viewpoint of cost.

Further, some of these substituents may include halogen, nitrile group, nitro group, amino group, silyl group, carbonyl group, carboxyl group, hydroxyl group, etc., within a range that does not impair the effects of the present invention.

The organic group having an amino group used in the present invention is not particularly limited, but a lower organic group is preferable. The @ group having an amino group is not limited to NH2, and various substituted amino groups can be used. Examples include N-alkylamino group, N,N-dialkylamino group, piperidino group, piperazino group, aminoethylamine group, and the like.

Examples of silicon compounds used in the present invention include 2-amine ethoxytrimethoxysilane, 3-aminopropoxytrimethoxysilane, 2-amino 3. (4)-Piperidinopropoxytrimethoxysilane, 2-aminoethoxytriethoxysilane, bis(3-aminopropoxy)
Dimethoxysilane, bis(3-(N,N-dimethyl)aminopropoxy)dimethoxysilane, tris(3-aminopropoxy)phenoxysilane, tetrakis(3-aminopropoxy)silane, 2.2.6-drimethyl-1
．． 3-dioxa-6-aza-2-silacyclooctane,
2,2-dimethoxy-6-methyl-1,3-dioxa-
Examples include 6-aza-2-silacyclooctane, methylsilatrane, ethylsilatrane, vinylsilatrane, methoxysilatrane, and the like.

Particularly preferred silicon compounds for use in the present invention are 2-aminoethoxytrimethoxysilane, 2,2-dimethoxy-6-methyl-1,3-dioxa-6-aza-
2-silacyclooctane and methylsilatrane.

The silicon compound used in the present invention may be added to the photosensitive layer or to the silicone rubber layer. Further, one layer may be provided as a contact layer between the photosensitive layer and the silicone rubber layer. Of course, these may be used in combination.

When the silicon compound of the present invention is added to the photosensitive layer, the amount added is 0.05 to 20% by weight, more preferably 0.
．． 1 to 10% by weight is selected, and if it exceeds 20% by weight, it is not only uneconomical but also reduces photosensitivity. Also, 0
．． If the amount is less than 0.05% by weight, the effect of improving adhesive strength will not be significant.

When added to the silicone rubber layer, 0.01 to 10
Heavy foot%, more preferably 0.1 to 5 heavy ω% is selected, 1
If it exceeds 0% by weight, it is not only uneconomical but also deteriorates the scratch resistance of the silicone rubber layer. Also, 0.0
If the amount is less than 1% by weight, the effect of improving adhesion will not be significant, so the amount added is preferably within the above range.

When the silicon compound used in the present invention is provided as an adhesive layer between the photosensitive layer and the silicone rubber layer, the coating thickness is 0.001 to 0.5 g/Tr12, more preferably 0.05 to 0.02q/Tr12. To be elected. When the thickness is increased, the developability deteriorates significantly.

Furthermore, if the thickness is less than 0.001 g/rn2, the effect of improving adhesive strength will be reduced, so the above range is desirable.

Examples of the quinonediazide compound used in the photosensitive layer of the present invention include quinonediazides normally used in positive PS plates, Wipon plates, photoresists, etc., such as benzoquinone-1,2-diazide-4- or -5-sulfone. Esters of acid and polyhydroxyphenyl, esters of naphthoquinone-1,2-diazide-4- or -5-sulfonic acid and pyrogallolacetylene resin, naphthoquinone-1,2-diazide-4- or -Esters of 5-sulfonic acid and phenol formaldehyde novolak resin, reaction products of quinone diazides and polyfunctional compounds such as polyfunctional isocyanates and polyfunctional epoxies as proposed in JP-A-56-80046@, etc. Can be mentioned.

Particularly preferable photosensitive layers in the present invention include an ester compound of naphthoquinone-1,2-diazide-5-sulfonic acid and phenol formaldehyde novolak resin, and a reaction between a complex of diazophenylamine and phosphotungstic acid and paraphenylene diisocyanate. It is a thing.

The thickness of the photosensitive layer is 0.1 to 100μ, more preferably 0.1μ to 100μ.
5-30μ is selected. If the thickness is not too thick, pinholes are likely to occur in the photosensitive layer, while if it is too thick, it is economically disadvantageous, so the above range is preferable.

The silicone rubber layer used in the present invention is mainly composed of a linear organic polysiloxane having several thousand to several hundred thousand molecules having repeating units as in the conventional method.

Here, n is an integer of 2 or more, R and R' are an alkyl group, an alkenyl group, or a phenyl group having 1 to 10 carbon atoms,
Preferably, 60% or more of R is a methyl group. A crosslinking agent is added to such a linear organic polysiloxane as necessary.

As a crosslinking agent, so-called room temperature (low temperature) #! These include acetoxysilane, oxime silane, alkoxysilane, aminosilane, amidosilane, etc., which are used in chemical-type silicone rubber, and are usually combined with linear organopolysiloxanes with hydroxyl groups at the terminals to produce acetic acid-removed type silicone rubber. , deoxime type, dealcoholized type, deamined type, and deamidated type silicone rubber. A small amount of an organic tin compound or the like may be added as a catalyst to these silicone rubbers.

The appropriate thickness of the silicone rubber layer is about 0.5 to 100μ, preferably about 0.5 to 30μ; if it is too thick, it is not only economically disadvantageous, but also difficult to remove during development. This results in a decrease in image reproducibility.

The support must be flexible enough to be set in a normal lithographic printing machine and must be able to withstand the load applied during printing. Typical examples include aluminum, copper,
Metal plates such as zinc and steel, polyethylene terephthalate,
Examples include a plus deck film or sheet such as polystyrene or polypropylene, a support having rubber elasticity such as chloroprene rubber or NBR, a support having such a rubber elastic layer, or coated paper. It is also possible to coat these supports with other substances for antihalation purposes and other purposes.

For the purpose of protecting the silicone rubber layer that forms the surface of the waterless lithographic printing plate constructed as described above, a thin protective film that has been subjected to a brain or uneven treatment is laminated to the surface of the silicone rubber layer, or a thin plastic sheet is used. A protective layer can also be formed by coating or transferring a similar material.

The waterless lithographic printing plate according to the present invention is manufactured, for example, as follows. First, a composition solution to form a photosensitive layer is applied onto the support using a conventional coater such as a reverse roll coater, air knife coater, or Meyer bar coater, or a rotary coater such as a Whaler, and then dried and coated as necessary. Heat up accordingly. If necessary, after applying an adhesive layer, a silicone gum solution is applied on the photosensitive layer in the same manner, and is heat-treated for several minutes at a temperature of usually 50 to 130°C to fully cure and form a silicone rubber layer. do. Further, if necessary, a protective layer may be further applied, and a protective film may be covered on the silicone rubber layer using a laminator or the like.

The waterless lithographic printing plate of the present invention thus produced is exposed to actinic light through, for example, a vacuum-adhesive negative film. The light source used in this exposure step is one that generates ultraviolet rays, and can be a mercury lamp, a carbon arc lamp, a xenon lamp, a methyl halide lamp, a tungsten lamp, a fluorescent lamp, or the like.

The printing plate is then rubbed with a developing pad containing a developer to remove at least the silicone layer in the image area, leaving the printing plate with the exposed surface of the photosensitive layer or support serving as the ink-receiving surface.

Hereinafter, the present invention will be explained in detail by giving Examples.

(Example) Example 1. Comparative Example 1 Aluminum plate with a thickness of 0.24 mm (manufactured by Sky Aluminum Co., Ltd.)
Coat the following photosensitive composition on top of the photosensitive composition.
A photosensitive layer having a thickness of 1.5 μm was formed by heat treatment for a second.

(1) 100 parts by weight (2>4.4' of naphthoquinone-1,2-diazide-5-sulfonic acid ester of phenol novolak resin (Sumilight Resin PR50731, manufactured by Sumitomo Duress Co., Ltd.) with a degree of esterification of 25%) -Diphenylmethane diisocyanate 35 parts by weight (3) Dibutyltin diacetate 0.2 parts by weight (4>
P-toluenesulfonic acid 0.8 parts by weight (5)
520 parts by weight of tetrahydrofuran Subsequently, a silicone gum composition having the following composition was spin-coated thereon, and 1
2.5 by moist heat curing at 20℃, dew point 30℃ for 3.5 minutes.
A waterless lithographic printing plate was prepared by providing a silicone rubber layer with a thickness of 8 μm, and then laminating a polypropylene film (8 μm thick, manufactured by Toshiku Co., Ltd.) as a cover film thereon.

(1) Polydimethylsiloxane (molecular weight approximately 2500
0゜Both ends are hydroxyl groups) 100 parts by weight (2)
Vinyltris(medylethylketoxime) silane 8 mm parts (3) Dibutyltin diacetate 0.1 parts by weight (4) 2-amine ethoxytrimethoxysilane 0.2 parts by weight (5) Isopar "E" (Exxon Chemical Co., Ltd.) aliphatic hydrocarbon solvent)/methyl isobutyl ketone (85
/15 weight ratio) After storing the waterless lithographic printing original plate containing 1800 parts by weight at room temperature for 2 weeks,
Using a metal halide lamp (Miyazaki Electric Co., Ltd. "Idol Fin 2000"),
The entire surface was exposed to UV402A> with an illuminance of 11 mW and 10 yf for 5 seconds.

A gradation negative film with halftone dots from 2% to 98% at 150 lines/inch was vacuum-adhered to the printing plate fully exposed as above, and the above metal halide lamp was used for 60 seconds at an illuminance of 11 mW/-. Image exposed.

Next, the cover film was peeled off, and the printing plate was treated with a pretreatment solution (Isoparpat 1/Butyl Calpitol/Ethyl Cellosolve/Monoethanolamine-90151510,
2 weight ratio) for 1 minute, take it out from the plate, soak the developing pad with the developing solution (water/butyl carbitol - 70/30 weight ratio), and rub the plate surface to easily remove the silicone rubber layer in the exposed area. A printing plate with an image faithful to the negative film was obtained. This printing plate was attached to an offset printing machine (manufactured by Shoshoku Spring Co., Ltd.) and printed using Toyo Ink Co., Ltd.'s "Ultra 70 Beni" without using dampening water. A printed matter with halftone dot reproducibility and no minute defects was obtained.

On the other hand, the silicone layer was obtained in the same manner as described in Example 1 except that 3-aminopropyltrimethoxysilane (0,2 parts of ffi) was used in place of the 2-aminoethoxytrimethoxysilane described in Example 1. The resulting printing plates also exhibited halftone dot reproducibility of 2% to 98%, but numerous scratches appeared on the surface of the silicone rubber layer in unexposed areas during development.

When a printing durability test was conducted using these printing plates under the following conditions, stains due to damage to the plate surface appeared on the printed matter after 1250 copies were printed.

On the other hand, similar stains appeared on the prints of the small sample after about 750 sheets, and there was a clear difference in the printing durability of the printing plates.

In this way, when 2-amine ethoxytrimethoxysilane was used, the adhesive strength between the photosensitive layer and the silicone rubber layer and the printing durability were improved.

Printing conditions Printing machine: Hamada Star 700 Modified machine Printing pressure: Underlay 500μ Ink: Osaka Ink Co., Ltd. 'I" OPI process red" Example 2 Same as Example 1 on an aluminum plate with a thickness of 0.3 mm A photosensitive layer was provided. On top of this, 2,2-dimethoxy-6-methyl-
0.5% of 1,3-dioxa-6-aza-2-silacyclooctane was applied to Isopar IT [the solution was applied and heated at 110°C].
It was dried in hot air to form a 0.05 μm thick tack layer. Subsequently, a silicone gum composition having the following composition was applied thereto using a Meyer bar coater, and then coated at 120'C1 dew point of 30°C, 3.
A silicone rubber layer having a thickness of 2.3 μm was provided by heating and curing in 5 minutes.

(1) Polydimethylsiloxane (molecule i25.0001
Hydroxyl groups at both ends) 100 parts by weight (2) Vinyltriacetoxysilane 8@middle (3) Dibutyltin diacetate 0.1 parts by weight (4>"Isopar" 6 430 parts by weight Printing obtained as above After storing the original plate at air temperature for two weeks, it was exposed imagewise using a metal halide lamp through a vacuum-adhesive negative film. When wet and lightly rubbed with a developing pad, the exposed areas are easily removed and the aluminum substrate is exposed, while the silicone rubber layer remains firmly in the unexposed areas, creating a printing plate that faithfully reproduces the negative film ( q. When this printing plate was attached to a normal proofing machine and printed on coated paper using waterless lithographic ink "Arbo" G (Eika Shiki Kagaku Kogyo Co., Ltd.), a sharp image was obtained. A print was obtained.

Example 3 The following photosensitive composition was coated on an aluminum plate with a thickness of 0.3 mm, and treated at 115° C. for 30 seconds to form a photosensitive layer with a thickness of 2 μm.

(1) 100 parts by weight (2>4,4°- Diphenylmethane diisocyanate 1 to 30 parts by weight (3) Dibutyltin diacetate 0.2 parts by weight (4)
P-Toluenesulfone M O, 8 parts by weight (5)
Methylsilatran 5 parts by weight (6)
1 part of tetrahydrofuran 520fflff Subsequently, the silicone rubber composition used in Example 2 was coated on this using a Meyer bar coater @120'C1 dew point 30°C, 3
．． A silicone rubber layer having a thickness of 2.5 μm was provided by heating and curing in 5 minutes.

After storing the waterless lithographic printing plate at room temperature for two weeks, the entire surface was exposed for 5 seconds at an illumination intensity of 11 mW/- using a UV meter (oak fabrication cut, UV402A>) using a metal halide lamp.

A negative film having a halftone image of 150 lines/inch was vacuum-adhered to the printing plate exposed entirely as described above in accordance with a conventional method, and imagewise exposed using a metal halide lamp. Next, this plate was immersed in a pretreatment solution (Isopar" l-1/Budilka J Levitol/Ethyl Cellosolve/Monoethanolamine = 90151510.21 ratio) for 1 minute, then taken out, and a developer solution (water/water/ When the printing plate was rubbed with butylcarpitol (70/30 ratio), the silicone rubber layer in the exposed areas was removed, exposing the surface of the photosensitive layer, and an image faithful to the original film was obtained.

Similar to Example 1, this printing plate also did not have any peeling of the silicone rubber layer in the unexposed areas during development or printing, nor did any scratches or the like occur on the surface of the silicone rubber layer.

Comparative Example 2 A printing plate obtained in the same manner as described in Example 3 except that 3-aminopropyltrimethoxysilane (5 Kawaguchi part) was used in place of methylsilatrane in Example 3.
Although the halftone dot reproducibility was 98%, numerous scratches were generated on the surface of the silicone rubber layer in the unexposed areas during development.

(Effects of the Invention) The present invention is configured as shown in the above (a) above, so that it is possible to increase the adhesive force between the photosensitive layer and the silicone rubber layer and to stabilize the adhesive force over time. The scratch resistance and solvent resistance of the silicone rubber layer and the printing durability of the printing plate can be dramatically improved.

Claims (1)

[Claims] In a waterless planographic plate formed by laminating a support, a photosensitive layer containing a quinonediazide compound, and a silicone rubber layer in this order, the photosensitive layer and the silicone rubber layer have the following general formula (
At least one of the silicon compounds represented by I) to (III)
A waterless lithographic printing original plate characterized by being bonded by seeds. ▲There are mathematical formulas, chemical formulas, tables, etc.▼...(I) ▲There are mathematical formulas, chemical formulas, tables, etc.▼...(II) ▲There are mathematical formulas, chemical formulas, tables, etc.▼...(III) (Here R_1, R_2, and R_5 are alkyl groups having 1 to 15 carbon atoms, aryl groups having 6 to 10 carbon atoms, and aralkyl groups. R_3, R_4, and R_6 are alkyl groups having 1 to 15 carbon atoms, alkoxy groups, or 6 carbon atoms. ~10 aryl group, aryloxy group. A_1, A_2 are organic groups having 1 to 10 carbon atoms and having an amino group. l and m are integers of 0 to 3, n
, p is an integer from 0 to 4, n+p≧1, 0+m+n+
p=4. s, t, and u are integers from 2 to 5. )