JPS6167864A - Original plate for waterless lithographic printing - Google Patents

Abstract

PURPOSE:To obtain stable and excellent image reproducibility without receiving the influence of the temp. and oxygen concn. in the stage of photoengraving and exposing by providing a photosetting adhesive layer on a substrate and forming a silicone rubber layer thereon. CONSTITUTION:The photosetting adhesive layer 2 is formed on the substrate 1 and further the silicone rubber layer 3 is provided thereon. The layer 2 is formed of a mixture contg. a monomer, oligomer or polymer having >=2 carbon- carbonunsatd. bonds for each one molecule and a compd. contg. >=2 mercapto groups for each one molecule. The layer 3 is formed of the silicone rubber having a carbon-carbon unsatd. bond. A protective film 4 is provided to the surface if necessary. If such original plate for lithographic printing is used, the printed matter having the stable and excellent image reproducibility is obtd. without receiving the influence of the temp. and oxygen concn. in the stage of photoengraving and exposing as the layer 2 is set by the addition reaction of the mercapto groups and the carbon-carbon unsatd. bond.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an original plate for waterless planographic printing that can be printed without using dampening water.

[Conventional technology]

Regarding lithographic printing plates that can be printed without using dampening water,
Several inventions have been made in the past.

For example, Special Publication No. 54-26923. Special Public Service 1986-231
The lithographic printing plate and lithographic printing original plate disclosed in No. 50 provide a lithographic printing plate that has excellent printing durability and is highly practical and does not require dampening water.

[Problem that the invention seeks to solve]

In Japanese Patent Publication No. 54-26925, the composition of the photosensitive layer is (1) a photopolymerizable composition containing an ethylenically unsaturated monomer, (2) a photocurable diazo resin, an azide resin, or a composition containing an azide resin; However, in these photosensitive layer compositions, printing plates using azide resin components have
There are problems such as the tendency to change over time and the narrow development latitude and poor workability in the plate development process during printing plate creation (Photopolymerizable composition containing 11 ethylenically unsaturated monomers) Those having this as a photosensitive layer component are excellent in practicality.

Also, in Japanese Patent Publication No. 56-26150, substrates.

A photopolymerizable adhesive layer containing an ethylenically unsaturated monomer or oligomer and a photoinitiator provided on the substrate, and a silicone rubber layer obtained by condensation type crosslinking provided on the photopolymerizable adhesive layer. These basic configurations provide waterless planographic printing plates that are particularly highly practical.

However, when such ethylenically unsaturated monomers or oligomers are used as components of the photopolymerizable adhesive layer, the speed of the photocuring reaction is affected by temperature and oxygen concentration;
If the temperature is too low or the oxygen concentration is too high in the plate-making exposure process, there is a problem that sufficient sensitivity and halftone dot reproducibility cannot be obtained.

The object of the present invention is to provide a waterless lithographic printing original plate that is not affected by temperature and oxygen concentration during the plate-making exposure process, without compromising the advantages of this original printing plate.

[Failure to solve the problem]

The present invention provides a waterless planographic original plate comprising a substrate, a photocurable adhesive layer provided on the substrate, and a silicone rubber layer provided on the photocurable adhesive layer, in which the photocurable adhesive layer is .

(1) Monomers, oligomers, or polymers having two or more carbon-carbon unsaturated bonds per molecule, and (2) compounds containing two or more mercapto groups per molecule.

The silicone rubber layer consists of a mixture containing.

A waterless lithographic printing original plate made of silicone rubber having carbon-carbon unsaturated bonds. In particular, photo-curing and photo-adhesion are achieved by the reaction between mercapto groups and carbon-carbon unsaturated bonds, which are not affected by temperature or oxygen. The present invention relates to a waterless lithographic printing original plate characterized in that:

The present invention will be explained in detail according to the drawings. FIG. 1 shows a lithographic printing original plate according to the present invention, and shows a substrate 1. Photocurable adhesive layer 2
and a silicone rubber layer 6 provided thereon, and a protective film 4 may be further provided thereon if necessary.

As shown in FIG. 2, when exposed through the positive film 5, the photocurable adhesive layer in the non-image area is cured and firmly bonded to the upper silicone rubber layer. On the other hand, since the photoadhesive layer in the image area is not exposed to light, its bond with the upper silicone rubber layer is weak.

After exposure, the unexposed area of the silicone rubber layer is peeled off by dipping it in a developer that reduces the adhesive strength between the silicone rubber and the photoadhesive layer and rubbing it lightly, and the underlying layer is photocured as shown in Figure 3. The surface 2' of the adhesive layer is exposed to provide sharp image areas with excellent ink receptivity. On the other hand, the silicone rubber layer 3' in the exposed area is strongly adhered by the curing of the photocurable adhesive layer, and remains on one plate surface to provide an ink-repellent non-image area.

The substrate 1 in the present invention is made of plastic such as aluminum, steel, polyester, and polyamide.

Rubber, coated paper, or a composite material thereof is used.

The photocurable adhesive layer 2 used in the present invention is:

It is photocured by irradiation with active light and has the property of strongly adhering to the upper silicone rubber layer. The photocurable adhesive layer can have any thickness as long as it is uniformly applied to the substrate and is in close contact with the substrate.

Preferably it is 100 microns or less, with 50 microns or less being more useful. If necessary.

It is also useful to provide an anchor coat layer between the substrate and the photocurable adhesive layer for the purpose of improving the adhesion between the photocurable adhesive layer and the substrate or preventing halation during plate-making exposure.

The photocurable adhesive layer used in the present invention preferably has the composition shown below.

(1) Monomers, oligomers, or polymers having two or more carbon-carbon unsaturated bonds in the same molecule
100 parts by weight (2) Compound having two or more mercapto groups in the same molecule 1
0 to 1000 parts by weight (3) If necessary, a monomer, oligomer, or polymer having one or more carbon-carbon unsaturated bonds and one or more mercapto groups in the same molecule 0 to 1000 parts by weight Part (4)
If necessary, add sensitizer fi+, (0 to 2 for the sum of 21 and (3))
0% by weight (5) If necessary, polymer or inorganic powder il+ as a filler, +21 and 0 to 1% relative to the sum of (3)
000% by weight of the above carbon-carbon unsaturated bond-containing compound.

The mercapto group-containing compound is essential as a photocurable adhesive component of the present invention, and contributes to increasing the adhesive force with the upper silicone rubber layer upon irradiation with actinic rays.

A carbon-carbon unsaturated bond is one that is reactive with a mercapto group, and has the general formula (where R, R, R, and R are hydrogen or halogen atoms.

(respectively means a substituted or unsubstituted alkyl group, aryl group, aralkyl group, or alkoxy group having 1 to 10 carbon atoms), and does not include aromatic unsaturated bonds.

The above carbon-carbon unsaturated bond-containing monomers, oligomers, and polymers include:

(1) Diene monomer and its oligomer.

Polymer (2) Polymer of monomers having two unsaturated bonds in one molecule (3) Reaction product of unsaturated bond-containing alcohol and polyvalent incyanate compound (4) Unsaturated bond-containing incyanate and Reaction product with a compound containing a polyvalent hydroxyl group or a polyvalent amine (5) Reaction product between an epoxy compound containing an unsaturated bond and a polyvalent carboxylic acid or a polyvalent amine (6) A reaction product between an unsaturated bond-containing alcohol and a polyvalent carboxylic acid Reaction products with acids (7) Reaction products with unsaturated bond-containing carboxylic acids and polyhydric alcohols (8) Reaction products with unsaturated bond-containing compounds and polyhydric amines.

What is a mercapto group-containing compound in the present invention?

It has a structure represented by the general formula below.

R5+5H) 111 (In the formula, n is an integer of 2 or more, R5 is a polyvalent organic group having 2 or more carbon atoms, and can contain a heteroatom such as N, S, O, P, etc.) Compounds include polyvalent mercapto group-containing aliphatic hydrovalents such as 1,6-dimercaptohexane and 1,10-dimercaptodecane, and thio-F IJ cholic acid, α-mercaptopropionic acid, β-mercaptopropionic acid and the like. Examples include esters with polyhydric alcohols.

A sensitizer is added to these compositions as necessary, and such a sensitizer is benzophenone.

Acetophenone, acenaphthoquinone, etc. can be found.

The silicone rubber 6 used in the present invention is.

Useful silicone rubbers have a thickness of 0.5 to 50 microns, preferably 0.5 to 10 microns, and transparency that allows actinic rays to pass through.Useful silicone rubbers include linear organopolysiloxanes represented by the following general formula. Obtained by crosslinking.

(In the formula, Rl and R2 are substituted or unsubstituted alkyl groups, alkenyl groups, and aryl groups having 1 to 10 carbon atoms, and those in which the total of methyl groups and vinyl groups exceeds 60 groups are particularly preferred.) The structure may optionally have a branched or cyclic structure.

A general method for crosslinking linear organopolysiloxanes includes a method of crosslinking linear organopolysiloxanes using a silicon compound containing a hydrolyzable functional group directly bonded to a silicon atom.

In particular, organopolysiloxanes with a molecular weight of several thousand to several million having a silanol structure at the end, alkoxy groups, acyloxy groups, ketoximate groups, amide groups, aminooxy groups, amino groups, alkenyloxy groups, and hydrogen directly bonded to silicon atoms. A commonly used method is to cure the rubber by reaction with a silicon compound having two or more functional groups such as the following. However, it is also possible to cure the organopolysiloxane to form a rubber using a radical initiator. It is optional to add a known crosslinking solvent during these cures.

The carbon-carbon unsaturated bond in the silicone rubber layer in the present invention is reactive with mercapto groups, and has the role of increasing the adhesive force with the photocurable adhesive layer in the exposed area.
Examples of the functional group include substituted or unsubstituted alkenyl groups. As a method for introducing these carbon-carbon unsaturated bonds into a silicone rubber layer.

(1) A group containing an alkenyl group such as a vinyl group.

Method for crosslinking organopolysiloxane having xane units to make rubber (2) Hinyltriacetoxysilane, vinyl) Alkenyl directly bonded to silicon atoms such as IJs (methyl ethyl ketoxime) silane, vinyl trimethoxy heptane, allyltriethoxysilane, etc. Examples include a method of crosslinking a linear organopolysiloxane to form a rubber using a silicon compound having a group.

In the laminated printing master plate described herein.

It is optional to further provide various silicone rubber layers on the silicone rubber layer, and an organic film laminate or a plastic coating may be applied on the silicone rubber layer for the purpose of surface protection.

The lithographic printing original plate as a laminate according to the present invention as explained above is manufactured, for example, in the following manner.

First, a composition for a photocurable adhesive layer is applied onto the substrate 1 and dried.Next, a silicone solution is applied onto the photocurable adhesive layer 2, dried, and sufficiently cured to form a silicone rubber layer 6. form. A protective film 4 is pasted on this as needed.

The lithographic printing original plate of the present invention manufactured in this way is
As shown in FIG. 2, the film is exposed to actinic rays through a positive film 5 which is sealed in vacuum. In FIG. 2, an arrow 6 indicates a light ray, and a two-image line portion is indicated by 7. As the light source used in this exposure process, a high pressure mercury lamp, a carbon arc lamp, a xenon lamp, a metal halide lamp, a fluorescent lamp, etc. can usually be used.

It is dipped into the exposed printing plate. developer.

The developing method is known (Japanese Patent Application Laid-open No. 54-89805.
-156947) can be used, and when one plate surface is dried after development, a waterless lithographic printing plate having a plate surface as shown in FIG. 6 is obtained.

〔Example〕

Examples are described below. The number 2 parts in the examples indicates parts by weight. In addition, in the examples, the reaction product of incyanate and alcohol is described, but the two reactions were conducted at a concentration of 10% in dioxane and 0.01% by weight based on the incyanate compound.
The reaction was carried out at 30° C. using dibutyltin silaurylate as a catalyst.

Example 1 (a) Triisocyanate “T-1” manufactured by Toshi Co., Ltd.
00j 55.46g (0.2 mol) of aliphatic polyester with hydroxyl groups at both ends, "Plaxel 2" manufactured by Chisso Corporation
08J 85. Og (0.1 mol).

Allyl alcohol 23.2 g (0.4 mol) Compound obtained by total reaction 40 parts (b) 1.
10-Dimercapto normal decane 20 parts (C) Pe/Zofeno 7 5 parts (d)
Bayer's polyurethane "Inplanil ELNj"
40 parts as a dioxane solution,
It was coated on a grained aluminum plate using a rotary coating machine to form a photocurable adhesive layer (thickness: 6 microns). on this photocurable adhesive layer.

(e) α, ω-Dihydrox-7 boridimethylsiloxane (number average molecular weight 40,000) ioo parts (f) vinyltriacetoxysilane 10 parts (ω) A composition consisting of 0.5 parts of diptyltin diacetate was dissolved in n-hexane. It was coated using a rotary coater and cured to form a silicone rubber layer (thickness: 3 microns).

A polypropylene film with a thickness of 6 microns was applied to the surface of the silicone rubber layer thus obtained.
"Torefan" was laminated using a calendar roller to obtain a printing plate master plate.

A positive film was vacuum-adhered onto the printing plate master plate thus obtained, and exposed for 1 minute at 39°C from a distance of 1 m using a metal halide lamp and Idol Fin 2000J manufactured by Iwasaki Electric Co., Ltd. Protective film When the original printing plate used as the exposure source was immersed in a developer consisting of 95 parts of n-hebutane and 5 parts of polypropylene glycol (molecular weight 400) and developed with "Sofpad" manufactured by Dynic Co., Ltd., the unexposed areas were removed. Only the silicone rubber layer was peeled off, exposing the photocurable adhesive layer. on the other hand.

The silicone rubber layer in the exposed area was strongly photo-adhesive.

When the developed printing plate was set in an offset printing machine and printed using Toyo Ink Co., Ltd.'s printing ink "TKU Aquares G" without adding dampening water, printed matter with excellent image reproducibility was obtained. Ta.

Further, the obtained printing original plate was exposed to light at an ambient temperature of 15° C., developed, and printed.

A printed matter with excellent image reproducibility was obtained. The gray scale sensitivity decreased by only 0.3 steps compared to when the exposure temperature was 30° C., and it was confirmed that the image reproducibility hardly changed even when the temperature changed during exposure.

When the obtained printing original plate was exposed to light at 30° C. in an air atmosphere, developed, and printed, printed matter with excellent image reproducibility was obtained. Therefore, it was confirmed that the oxygen concentration during exposure did not affect image reproducibility.

Comparative example 1 On a grained aluminum plate.

(a) Bayer polyurethane “Inplanil gbN”
J 60 parts (b) 4:1 molar reaction product of glycidyl methacrylate and xylylene diamine 40 parts (C) Michler's ketone
An ethyl cellosolve solution having a composition of 5 parts was applied using a spin coater to form a photocurable adhesive layer (
6 microns thick). on this photocurable adhesive layer.

(d) α,ω-Dihydroxypolydimethylsiloxane (number average molecular weight 40,000) 100 parts (8) Ethyltriacetoxysilane 10 parts (f) A composition consisting of 0.5 parts of dibutyltin diacetate was rotated as an n-hexane solution. It was coated with a coating machine and cured to form a silicone rubber layer (thickness: 3 microns). The obtained laminate was laminated with "Trephan" in the same manner as in Example 1.

A printing original plate was obtained.

The obtained printing original plate was heated under reduced pressure in the same manner as in Example 1.
When exposed and developed under the conditions of 0°C and 15°C, the grayscale sensitivity of the image exposed at 15°C was 1.8 steps lower than that of the image exposed at 30°C.

Further, when the obtained printing original plate was exposed to light at 30° C. in an air atmosphere and developed, the silicone rubber layer was peeled off in the exposed areas, and a printing plate that could not be used as a printing plate was obtained.

Example 2 The composition of the silicone rubber layer in Example 1.

(a) 100 parts of α,ω-dihydroxypolydimethylsiloxane (number average molecular weight approximately 40,000) (b) 10 parts of allyltrimethoxysilane (C) 0.5 part of dibutyltin diacetate in the same manner as in Example 1. When a printing original plate was prepared, exposed, developed and printed, a printed matter with excellent single image reproducibility was obtained.

Example 6 The composition of the silicone rubber layer in Example 1.

(a) Random copolymer of dimethylsiloxane-methylvinylsiloxane (weight ratio 9/1) with hydroxyl groups at both ends (number average molecular weight approximately 10,000) (b) 5 parts ethyltriacetoxysilane (C) dibutyltin diacetate) A printing original plate was prepared as 0.2 parts, and exposed, developed, and printed in the same manner as in Example 1, and a printed matter with excellent image reproducibility was obtained.

Example 4 The composition of the photocurable adhesive layer in Example 1.

(a) Compound (a) in Example 1 40 parts (b) Pentaerythritol tetra(β-mercaptopropiotate) 20 parts (C)
Benzophenone 5 parts (d) /
<Polyurethane manufactured by Inil Co., Ltd. “Inplanil ELNJ
In the same manner as in Example 1, except for the composition consisting of 40 parts.

When a printing plate original plate was prepared, exposed, developed, and printed, a printed matter with excellent image reproducibility was obtained.

Example 5 In the composition of the photoadhesive layer in Example 4, (1)) A printing plate precursor was prepared using pentaerythritotetetra (bentaerythritotetetrathioglycolate instead of β-mercaptopropionate), and Example 4 When exposed, developed and printed in the same manner as above, a printed matter with excellent image reproducibility was obtained.

Example 6 In Example 1, the composition of the photocurable adhesive layer.

Ca> Toshi Co., Ltd. Exhibition Triisocyanate “T-1
00'' 53.5 g (0.2 mol) and 40.0 g (0.1 mol) of nopholyethylene glycol having a molecular weight of 400.

Allyl alcohol 23.2 g (0.4 mol) Totally reacted compound 30 parts (b) 1.
10-dimercapto-normal decane 20 parts <C) Benzophenone 5 parts (d
) Poly(n-butyl acrylic) with a molecular weight of 60.000
)

A printing original plate was prepared as 50 copies, and when exposed, developed and printed in the same manner as in Example 1, a printed matter with excellent image reproducibility was obtained.

Example 7 In Example 1, (a) as a photocurable adhesive layer component
40 parts (b) of a reaction product of 13.6 g (0.1 mol) of pentaerythritol and 33.2 g (0.4 mol) of allyl isocyanate.1.
10-Dimercapto normal decane 20 parts (C) Benzophenone 5 parts (d
) Molecular weight 50. A printing plate blank was prepared in the same manner as in Example 1 using a composition consisting of 60 parts of OOO polylauryl methacrylate, and when exposed, developed and printed, a printed matter with excellent image reproducibility was obtained.

Example 8 In Example 1, as a photocurable adhesive layer.

(a) Polyallyl methacrylate (molecular weight 15.0
00) 60 copies (b) 1. i
A printing plate precursor was prototyped with a composition consisting of o-dimercaptodecane 40 parts (e) and benzophenone 5 parts, and exposed, developed, and exposed in the same manner as in Example 1.
Just printed.

A printed matter with excellent image reproducibility was obtained.

Example 9 In Example 1, as a photocurable adhesive layer.

(a) Polybutadiene 1J manufactured by Japan Synthetic Rubber Co., Ltd.
sR-BR○1” 60 copies (b) 1.10-
A printing plate precursor was prepared with a composition of 35 parts of dimercaptodecane (C and 5 parts of benzophenone), and exposed, developed and printed in the same manner as in Example 1 to obtain a printed matter with excellent image reproducibility.

Example 10 As a photocurable adhesive layer in Example 1.

(a) 20 parts of 1.2.4.5-tetrakis(diallylamino)benzene (b)
-1,10-dimercapto-normaldecane 20 parts (C) Benzophenone 5 parts (d
) A printing plate precursor was prepared with a composition consisting of 40 parts of polyurethane "IMPRANIL zLNj" and exposed, developed and printed in the same manner as in Example 1 to obtain printed matter with excellent image reproducibility.

〔Effect of the invention〕 According to the original plate for waterless planographic printing according to the present invention.

Because the photocurable adhesive layer is based on an addition reaction between a mercapto group and a carbon-carbon unsaturated bond, it is less sensitive to temperature and oxygen during plate-making exposure than the previously proposed polymerization using ethylenically unsaturated monomers or oligomers. without being affected by concentration.

Printed matter with stable and excellent image reproducibility can be obtained.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional structural diagram of a planographic printing original plate based on the present invention. FIG. 2 is a conceptual diagram of the exposure process of the lithographic printing original plate. FIG. 6 is a cross-sectional view of the present lithographic printing plate obtained after plate making. 1: Substrate 2: Photocurable adhesive layer 3: Silicone rubber layer 4: Protective film 5: Positive film '31g

Claims (1)

[Scope of Claims] A photocurable adhesive layer in a waterless planographic original plate comprising a substrate, a photocurable adhesive layer provided on the substrate, and a silicone rubber layer provided on the photocurable adhesive layer. is from a mixture containing (1) a monomer, oligomer, or polymer having two or more carbon-carbon unsaturated bonds per molecule, and (2) a compound containing two or more mercapto groups per molecule. A waterless lithographic printing original plate characterized in that the silicone rubber layer is made of silicone rubber having a carbon-carbon unsaturated bond.