JPH05232713A - Plate surface correcting liquid for photosensitive planographic plate with no use of wetting water - Google Patents

Abstract

PURPOSE:To provide a surface correcting liquid for photo-sensitive planographic plate not requiring wetting water which does not wear easily and whose ink repulsiveness is not likely to degradate by using a silicone rubber composition containing linear diorgano-polysiloxane and specific silane compound. CONSTITUTION:A planographic plate surface correcting liquid includes at least a silicone rubber composition, catalyst, and solvent, wherein the silicone rubber composition contains at least linear diorgano-polysiloxane and silane compound as given by formula. In formula, R1, R2, R3 represent alkylene radicals such as methylene radical, ethylene radical, propylene radical, butylene radical, bentylene radical, hexylene radical, cyclohexylene, while A1, A2, A3 represent alkoxy radicals such as methoxy radical, ethoxy radical, propoxy radical. Favorable examples of oxym radical are dimethyl ketoxym radical, diethyl ketoxym radical, etc. The resultant product gives good hardening speed, excels in adhesion with the plate surface, and presents good ink repulsiveness.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plate surface correction liquid for a photosensitive lithographic printing plate which does not require fountain solution, and more specifically, has good ink repulsion and adhesiveness, excellent abrasion resistance and curing speed. The present invention relates to a favorable plate surface correction liquid for a photosensitive lithographic printing plate that does not require fountain solution.

[0002]

BACKGROUND OF THE INVENTION In the conventional printing method that requires dampening water, it is difficult to control the delicate balance between the dampening water and the ink, which causes emulsification of the ink or causes the ink to sprinkle in the dampening water, resulting in poor ink density. It had a big problem that it causes stains and scumming and becomes a major cause of waste paper, but a photosensitive lithographic printing plate that does not require a dampening water in which a primer layer, a photosensitive layer and a silicone layer are provided in this order on a support is It has numerous advantages because it does not require dampening water.

However, since the silicone layer is relatively vulnerable to scratches, scratches are likely to occur during handling, and it is suitable for correcting defects that have occurred once such as scratches, pinhole-like defects, defects due to film edges, etc. There was no means and it was inconvenient to use. On the other hand, there are cases where not only an unexpected defect but also a correction such as a mistakenly drawn image line portion is intentionally erased to make it a non-image line portion.

Various studies have been conducted on a correction fluid therefor. For example, to improve the curing speed,
It is also known that a correction liquid contains a filler such as a silane compound or fine powder silica in order to improve the adhesion to the plate surface and the abrasion resistance during printing.

However, since such a correction liquid contains a large amount of a filler, there is a problem in that the portion coated with the correction liquid is contaminated due to a decrease in ink repulsion.

[0006]

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is that the curing speed is good, the adhesiveness to the plate surface is excellent, and the abrasion is caused during printing. Another object of the present invention is to provide a plate surface correction liquid for a photosensitive lithographic printing plate that does not require dampening water and that does not deteriorate ink repulsion.

[0007]

The above object of the present invention is to provide a photosensitive lithographic plate not requiring a fountain solution having a silicone rubber composition containing at least a linear diorganopolysiloxane and a silane compound represented by the general formula (I). It is achieved by a plate surface correction liquid for printing plates.

[0008]

[Chemical 2]

The present invention will be described in more detail below.

The fountain solution-free photosensitive lithographic printing plate surface correcting solution of the present invention contains at least a silicone rubber composition, a catalyst and a solvent. The silicone rubber composition contains at least a linear diorganopolysiloxane and a silane compound represented by the general formula (I).

In the general formula (I), R ₁ , R ₂ or R ₃
The alkylene group represented by is, for example, a methylene group, an ethylene group, a propylene group, a butylene group, a pentylene group, a hexylene group, a cyclohexylene group, etc., and the alkoxy group represented by A ₁ , A ₂ or A ₃ is, for example, a methoxy group,
It is preferably an ethoxy group or a propoxy group, and the oxime group is preferably a dimethylketoxime group or a diethylketoxime group. These groups may have a substituent, and examples of the substituent include a phenyl group, a methyl group and an ethyl group. Specific examples of the silane compound represented by the general formula (I) preferably used in the present invention are shown below.

[0012]

[Chemical 3]

In the present invention, the silane compound represented by the general formula (I) is preferably contained in a proportion of 1.0 to 10 parts with respect to 100 parts of the linear diorganopolysiloxane in the correction liquid.

The linear diorganopolysiloxane used in the present invention is dimethylpolysiloxane having hydroxyl groups at both ends of the molecular chain.

The diorganopolysiloxane having hydroxyl groups at both ends of the molecular chain as referred to herein is an average composition formula And R is an alkyl group having 1 to 10 carbon atoms, an alkoxyl group, a vinyl group, a hydroxyl group or an aryl group, which may have an appropriate substituent. Generally R
It is preferable that 60% or more is a methyl group and 40% or less is a vinyl group, a phenyl group, a vinyl halide group, a halogenated phenyl group, or the like.

In the present invention, the number average molecular weight is 1,000 to 1,000.
It is preferred to use linear diorganopolysiloxanes in the range of 000.

In the present invention, it is preferable to contain a polyfunctional silane compound in addition to the silane compound represented by the general formula (I). Examples of the polyfunctional silane compound used in the present invention include a trimethoxysilyl group, an amino group,
The silane compound which has a glycidyl group, a methacryl group, an allyl group, a vinyl group etc. can be mentioned. In the present invention, the polyfunctional silane compound is preferably contained in an amount of 0.5 to 5 parts based on 100 parts of the linear diorganopolysiloxane.

In the present invention, a catalyst is used if necessary. Examples of the catalyst used include tin compounds such as dibutyltin acetate, dibutyltin octoate, stannas octoate and dibutyltin laurate. The amount used is preferably in the range of 0.5 to 10 parts based on 100 parts of linear diorganopolysiloxane.

In addition to the above-mentioned components, the plate surface correction liquid of the present invention may contain various fillers and additives, if necessary, as long as the object of the present invention is not impaired. As the filler, finely powdered silica, silica aerogel, precipitated silica, diatomaceous earth, iron oxide, zinc oxide, metal oxides such as titanium oxide, or those whose surfaces are silanized,
Examples include metal carbonates such as calcium carbonate, magnesium carbonate and zinc carbonate, asbestos, glass wool, carbon black, finely powdered mica and fused silica powder.

The correction fluid of the present invention may be obtained by diluting the silicone rubber composition with a volatile solvent, if necessary. As the volatile solvent used in the present invention,
Paraffinic hydrocarbons with boiling points in the range of 50-150 ° C,
Examples thereof include isoparaffin hydrocarbons, aromatic hydrocarbons and mixtures thereof. Specific examples thereof include hexane, cyclohexane, heptane, isopentane, octane, isooctane, toluene, xylene, isopentane, isooctane, etc. Among them, hexane, cyclohexane and a mixed solvent containing these solvents as main components are preferable.

The concentration of the correction liquid in the present invention depends on the molecular weight of the diorganopolysiloxane used and the coating method, but is in the range of 5 to 90% by weight, preferably 20 to 50% by weight. If the concentration of the correction fluid is too thin or too thick, it is difficult to apply, and a silicone rubber thin film having an appropriate thickness cannot be obtained.

Such a correction fluid can be used with an ordinary brush, sponge,
Tools such as pipettes, syringes and the like can be used to apply to the revision area.

The plate surface correction liquid of the present invention can be applied to known lithographic printing plates which do not require fountain solution. In particular, it can be applied to a photosensitive lithographic printing plate which does not require fountain solution in which a photosensitive layer and a silicone rubber layer are laminated on a substrate or a primer layer on the substrate. For example, as described in JP-B-44-23042 and JP-B-46-16044, a photosensitive lithographic printing plate which does not require a fountain solution is disclosed in which a photo-soluble or photo-insoluble photosensitive layer and a silicone rubber layer are laminated on a substrate. -94504, JP-A-50-50102, a photosensitive lithographic printing plate which does not require a fountain solution, wherein a photoadhesive photosensitive layer and a silicone rubber layer are laminated on a substrate, JP-A-55-55343
JP-A 2-63050 and JP-A 2-63051, a photosensitive lithographic printing plate not requiring a fountain solution having a protective layer having irregularities on a silicone rubber layer, JP-A-55-161244, Sho 63-1331
53, JP 62-50760, JP 1-172834, JP 2-
No. 34857, JP-A Nos. 1-118843 and 1-150142, a photosensitive lithographic printing plate which does not require a fountain solution is prepared by laminating a primer layer, a photosensitive layer and a silicone rubber layer on a substrate.
No. 56-80047, and a photolithographic photosensitive layer and a silicone rubber layer laminated on a substrate can be applied to a photosensitive lithographic printing plate which does not require fountain solution.

Further, the present invention can be preferably applied to a photosensitive lithographic printing plate which does not require a fountain solution and can be developed with water, an aqueous developer or an aqueous alkali developer. For example, JP-A-61-2
Organic solvent described in 75759, surfactant, dampening water unnecessary photosensitive lithographic printing plate developable with a developer consisting of 30% or more water, JP-A-63-253949, 63-257748, 63-280
No. 250, No. 63-280251, JP-A No. 1-159644, No. 1-214839
No. 1-235955, No. 1-235956, water- or alkaline water-soluble or swellable polymer compound, a photopolymerizable monomer, a dampening having a photosensitive layer containing a photopolymerization initiator Examples include waterless photosensitive lithographic printing plates. Further, as a photosensitive lithographic printing plate which does not require a dampening solution, a dampening water-free photosensitive lithographic printing plate described in JP-A Nos. 2-282257 and 2-282258 can be used, for example, on a substrate. Or on the primer layer on the substrate, a copolymer of a monomer having an aromatic hydroxyl group, for example, N- (4-hydroxyphenyl) acrylamide, p-hydroxystyrene, etc. and another monomer, and diazo. Examples include a photosensitive lithographic printing plate that does not require a fountain solution in which a photosensitive layer containing a resin, for example, a hexafluorophosphate salt of a condensate of p-diazodiphenylamine and formaldehyde is laminated, and a silicone rubber layer is laminated on the photosensitive layer. ..

The substrate used in the present invention can be appropriately selected from known support materials used in photosensitive lithographic printing plates that do not require fountain solution.

Further, as the developing solution used in the present invention,
A conventionally known water-based alkaline developer used for a photosensitive lithographic printing plate that does not require fountain solution can be appropriately used.

The aqueous alkaline developer is a developer containing water as a main component, and is described in, for example, JP-A-61-275759, and contains 30% by weight or more of water, preferably An aqueous alkaline developing solution containing 90% by weight or more and an organic solvent, a surfactant, an alkaline agent and the like can be mentioned.

As the organic solvent contained in the alkaline developing solution containing water as a main component, for example, aliphatic hydrocarbons (hexane, heptane, "Isopar EHG" (produced by Esso Kagaku, aliphatic hydrocarbons) can be used. Brand name) or gasoline, kerosene, etc.), aromatic hydrocarbons (toluene, xylene, etc.),
Alternatively, halogenated hydrocarbons (trichlene, etc.), alcohols (methanol, ethanol, 1-butoxy-2-propanol, 3-methyl-3-methoxybutanol, β
-Anilino ethanol, benzyl alcohol, etc.), ethers (methyl cellosolve, ethyl cellosolve, butyl cellosolve, phenyl cellosolve, methyl carbitol, ethyl carbitol, butyl carbitol, dioxane, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol dibutyl ether, ethylene) Glycol dibutyl ether, propylene glycol, dipropylene glycol butyl ether, tripropylene glycol methyl ether, polypropylene glycol methyl ether, etc.),
Ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone, diisobutyl ketone, 4-methyl-1,
3-dioxolan-2-one etc.), esters (ethyl acetate, propyl acetate, hexyl acetate, methyl acetate, propyl acetate, diethyl succinate, dibutyl oxalate, diethyl maleate, benzyl benzoate, methyl cellosolve acetate, cellosolve acetate, Carbitol acetate, etc.) and the like.

As the surfactant added to the developing solution used in the present invention, anionic surfactants, nonionic surfactants, cationic surfactants and zwitterionic surfactants are used. Japanese Patent Application No. 2-206041 The surfactants described in the specification of the publication are used. These surfactants may be used alone or in combination of two or more. The amount of the surfactant used in the present invention is appropriately 0.01 to 60% by weight, preferably 0.1 to 10% by weight.

Further, as the alkaline agent used in the present invention, (1) sodium silicate, potassium silicate,
Potassium hydroxide, sodium hydroxide, lithium hydroxide,
Inorganic alkaline agents such as secondary or tertiary sodium phosphate or ammonium salt, sodium metasilicate, sodium carbonate, and ammonia, (2) mono-, di- or trimethylamine, mono-, di- or triethylamine, mono- or diisopropylamine, n-butylamine, Examples include organic amine compounds such as mono-, di- or triethanolamine, mono-, di- or triisopropanolamine, ethyleneimine, and ethylenediimine. The amount of the alkaline agent used is 0.05 to 20% by weight, preferably 0.2 to 10% by weight.

The plate surface correcting solution of the present invention is imagewise exposed to the photosensitive lithographic printing plate prepared as described above and then developed with a developing solution to form a photosensitive layer together with a silicone rubber layer on the image area, or a silicone rubber. As a result of removing only the layer, the primer layer or the photosensitive layer is exposed as an image portion and applied to the formed lithographic printing plate requiring no fountain solution.

[0032]

EXAMPLES The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples.

Example 1 Preparation of a photosensitive lithographic printing plate requiring no fountain solution An aluminum plate having a thickness of 0.2 mm was immersed in a 3% aqueous solution of sodium hydroxide for degreasing, washed with water, and then heated in a 40% aqueous solution of sulfuric acid. Anodize at 30 ° C and 1.5 A / dm ² for 2 minutes, wash with water, immerse in 1% aqueous sodium metasilicate solution at 85 ° C for 37 seconds, and further in water at 90 ° C (pH 8.5).
It was immersed for 25 seconds, washed with water and dried to obtain an aluminum substrate a.

A primer layer composition having the following composition was applied to an aluminum substrate a and dried at 85 ° C. for 3 minutes, and then 3 k
w An exposure of 1000 mJ / cm ² was performed using an ultra-high pressure mercury lamp and further drying was performed at 100 ° C. for 4 minutes to form a primer layer having a thickness of 5.0 μm.

Primer layer composition diazo resin-1 9 parts (hexafluorofluorophosphate of polycondensation product of p-diazodiphenylamine and paraformaldehyde, synthesized according to the method disclosed in JP-A-1-150142) Copolymer resin -1 91 parts (copolymer resin of 2-hydroxyethyl methacrylate and methyl methacrylate in a molar ratio 34/66) Zinc oxide pigment 30 parts (FINEX-25 manufactured by Sakai Chemical Industry Co., Ltd.) Yellow pigment 20 parts (KET-Yellow- 402 Dainippon Ink and Chemicals, Inc. 3-methacryloxypropyltrimethoxysilane 3 parts Methyl lactate 847 parts

Next, a photosensitive composition having the following composition was coated on the primer layer and dried at 85 ° C. for 2 minutes to give a thickness of 0.3 μm.
To form a photosensitive layer.

Photosensitive composition Diazo resin-1 50 parts Copolymer resin-2 50 parts (2-hydroxyethyl methacrylate, N- (4-hydroxyphenyl) methacrylamide, methacrylic acid in a molar ratio of 35/60/5 Polymerized resin) Victoria Pure Blue BOH 1 part (Hodogaya Chemical Co., Ltd., dye) Methyl lactate 3900 parts

Next, the following silicone rubber composition was applied onto the above-mentioned photosensitive layer and dried at 85 ° C. for 10 minutes to form a 1.8 μm silicone layer.

Silicone rubber composition α, ω-dihydroxypolydimethylsiloxane 100 parts (molecular weight 80,000) 1,3,5-tris (3-trimethoxysilylpropyl) isocyanurate 3.5 parts Dibutyl Sn dilaurate 0.8 parts Isopar E 800 parts ( Esso Kagaku Co., Ltd. Isoparaffinic solvent) Toluene 100 parts

Next, a polypropylene film having a thickness of 6 μm, one surface of which was matted, was laminated on the above silicone layer to obtain a water-free photosensitive lithographic printing plate which was moistened.

Next, a positive film was brought into vacuum contact with the above silicone rubber layer, and then exposed using a metal halide lamp as a light source.

After the exposed plate material was immersed in the following developing solution for 1 minute, the surface of the plate material was rubbed with a pad impregnated with the developing solution to remove the silicone rubber layer and the photosensitive layer in the image area. Got the edition.

[Developer] β-anilinoethanol 0.5 part Propylene glycol 1.0 part p-tert-Butylbenzoic acid 1.0 part Potassium hydroxide 1.0 part Polyoxyethylene lauryl ether 0.1 part Potassium sulfite 2.0 parts Potassium metasilicate 3.0 parts Water 91 Department

Preparation of plate surface correction liquids-1 to 4 A plate surface correction liquid having the following composition was prepared . (Printing plate correction liquid-1) (a) Linear dimethylpolysiloxane having hydroxyl groups at both ends (number average molecular weight of about 20,000) 100 parts by weight (b) 1,3,5-tris [3- (trimethoxysilyl) propyl] isocyanate Nulate 4.0 parts by weight (c) N-glycidyl-N, N-bis [3- (trimethoxysilyl) propyl] amine 2.0 parts by weight (d) Dibutyltin acetate 2.0 parts by weight (e) n-Hexane 400 parts by weight Liquid-2) (a) (d) (e) Same as plate surface correction liquid-1 (b) 1,3,5-tris [3- (trimethoxysilyl) propyl] isocyanurate 3.0 parts by weight (c) Vinyltri Acetoxysilane 4.0 parts by weight (plate surface correction liquid-3) (a) (d) (e) same as plate surface correction liquid-1 (b) 1,3,5-tris [3- (trimethoxysilyl) propyl] isocyanurate 3.0 parts by weight (C) γ-glycidoxypropyltrimethoxysilane 2.0 parts by weight (plate surface correction liquid-4) (a) (d) (e) same as plate surface correction liquid-1 (b) 1,3,5-tris [3 -(Trimethoxysilyl) propyl] isocyanurate 4.0 parts by weight (c) 3- (N-allyl-N-glycidyl) aminopropyl trimethoxysilane 2.0 parts by weight Plate correction liquid-5 (comparative example) (a) Plate correction liquid Same as -1 100 parts by weight (b) 15 parts by weight of vinyltriacetoxysilane (c) 8 parts by weight of dibutyltin acetate (d) 400 parts by weight of n-hexane Plate surface correction liquid-6 (comparative example) (a) Plate surface correction liquid- 1 and the same 100 parts by weight (b) vinyl tri (isopropenyloxy) silane 4 parts by weight _{(c) [(CH 3)} 2 N] 2 C = NC 3 H 6 Si (OCH 3) 3 1 part by weight (d) 3 -Aminopropyltriethoxysilane 1.2 parts by weight (e) Specific surface Fumed silica 8 parts by weight of 200m ² / g (f) n- hexane 400 parts by weight

The adjusted plate surface correction liquids -1 to 6 were respectively dried and applied on the image areas of the photosensitive lithographic printing plate, which was prepared by exposing and developing, so that the thickness after curing was about 2 μm. Then
It was dried and cured at room temperature and touched with a finger to measure the time (curing time) at which tackiness disappeared. The obtained dampening water-free photosensitive lithographic printing plate was attached to a Heidel GTO printing machine (manufactured by Heidelberg, Germany), and the temperature of the plate surface when the smear occurred on the portion where the plate surface correction liquid was applied was measured. The results are shown in Table 1.

Also, 20,000 or 40,000 sheets are printed,
The degree of peeling, scratches and abrasion of the portion coated with the correction liquid after printing was observed. The results are shown in Table 2.

[0047]

[Table 1]

[0048]

[Table 2]

[0049]

As described in detail above, according to the present invention, a photosensitive lithographic plate requiring no dampening water, which has a good curing speed, excellent adhesiveness to the plate surface, is hard to be worn during printing, and does not deteriorate ink repulsion property. It was possible to provide a plate surface correction liquid for a printing plate.

Claims (1)

[Claims] 1. A plate surface correction liquid for a photosensitive lithographic printing plate which does not require a fountain solution and which has a silicone rubber composition containing at least a linear diorganopolysiloxane and a silane compound represented by the general formula (I). [Chemical 1]