JP2000019722A - Printing plate correction liquid for planographic printing plate not needing damping water and printing plate correcting method for planographic printing plate not needing damping water - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide printing plate correction liquid for a planographic printing plate, excelling in liquid preservation stability and not needing damping water. SOLUTION: This printing plate correction liquid is used for correcting a drawing part to a non-drawing part in a planographic printing plate not needing damping water and having a silicone rubber layer used as an ink repellent layer, and the correction liquid is a solution comprising, (a) a polyvalent hydrogen organic polysiloxane, (b) a polysiloxane compound having two or more ethylenic unsaturated bonds in one molecule, (c) an organic titanate compound, and (d) an organic solvent.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a correction liquid for a lithographic printing plate requiring no dampening solution and a method for correcting a plate surface of a lithographic printing plate requiring no dampening solution, in which a silicone rubber layer is used as an ink repellent layer.

[0002]

2. Description of the Related Art Various printing plates for performing lithographic printing using a silicone rubber layer as an ink repellent layer and using no fountain solution have been proposed. Among them, those obtained by sequentially coating a photosensitive resin layer and a silicone rubber layer on a substrate in this order have excellent performance, and such a constitution is commercially available under the trade name of "waterless planographic printing plate".

However, since the silicone rubber layer is relatively easily damaged, scratches are likely to occur during handling. For this reason, the scratches, pinhole-shaped defects, or defects based on the film edge generated in the silicone rubber layer are erased and corrected, and in some cases, a normal image portion is erased to a non-image portion. A plate correction liquid is required.

Some plate surface correcting liquids for such a waterless planographic printing plate have been proposed. For example, Japanese Patent Publication No. 61-3417 discloses a plate surface correcting liquid comprising a one-part curable silicone rubber solution containing triacetoxysilane as a crosslinking agent. Japanese Patent Application Laid-Open No. 62-29
Japanese Patent Publication No. 9854 discloses a plate surface correcting liquid comprising a one-part curable silicone rubber solution containing a vinyloxysilane compound as a crosslinking agent. Also, JP-B 63-23
No. 547 discloses a plate surface correcting solution in which a linear diorganopolysiloxane, polyacetoxysilane and a catalyst are dissolved in a solvent mainly composed of paraffinic / isoparaffinic hydrocarbons. Further, JP-A-4-163195 discloses a plate surface correcting solution using a linear organopolysiloxane having three alkoxy groups at both ends.

Although the plate surface correction liquids disclosed in these patents have excellent adhesion to the image area, do not generate print stains, and provide a coating with excellent printing durability, the curing speed is not always sufficient. Further improvements were desired.

[0006] Further, the plate surface correcting liquid is contained in a closed plastic container for blocking moisture in the air. However, in the case of the conventional plate surface correcting liquid, a plastic solution between the time of manufacture and the time of use by a user is used. The storage stability of the solution in the inside was not sufficient, and depending on the conditions, the solution sometimes gelled in the container within one year. Therefore, it has been desired to improve the storage stability of the correction fluid so that the correction fluid does not gel in the container during the distribution and storage and can be used for one year or more after production.

[0007] However, the problem of improving the curing speed of the correction liquid and the problem of improving the storage stability of the correction liquid are contradictory. That is, increasing the curing speed means increasing the reaction activity of the liquid, and the storage stability tends to deteriorate. Conversely, if the storage stability is improved, the curing rate of the liquid tends to decrease.

Conventionally, the plate surface correcting liquid is placed in a pen-shaped plastic container, a hole is formed in the pen tip with a needle, and the liquid is discharged by pressing the belly of the container, and applied to the plate surface. In this case, although the method is suitable for correcting a small area, the workability is extremely poor when correcting a large area, and it is difficult to apply the solution uniformly. Using a brush or a brush to apply the correction liquid to a large area improves workability, but the conventional condensation-type silicone rubber solution has extremely poor brush holding properties, There was a problem of being cured.

[0009]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a correction liquid which is suitable for correcting a relatively large area using a brush or a brush and has excellent brush durability in air, and a distribution and storage method. An object of the present invention is to provide a plate surface correcting solution which can be used for a long period of time and has improved storage stability without gelation in a container over time. Another object of the present invention is to provide a correction liquid which does not decrease the curing speed, has excellent adhesion to an image area, does not generate printing stains, and provides a coating excellent in printing durability.

[0010]

SUMMARY OF THE INVENTION The object of the present invention is as follows.
A plate surface correcting liquid for correcting an image area to a non-image area in a lithographic printing plate requiring no dampening solution using a silicone rubber layer as an ink repellent layer, wherein the correction liquid is (a) a polyvalent hydrogen organic poly 100 parts by weight of siloxane (b) 0.1 to 100,000 parts by weight of polysiloxane compound having two or more ethylenically unsaturated bonds per molecule (c) Organic titanate compound (d) A solution comprising an organic solvent This is achieved by a plate surface correcting solution for a lithographic printing plate which does not require dampening solution.

[0011] A plate surface correction method for correcting an image portion to a non-image portion in a fountain solution-free lithographic printing plate having a silicone rubber layer as an ink repellent layer, comprising: (a) a polyvalent hydrogen organic compound; 100 parts by weight of polysiloxane (b) 0.1 to 100,000 parts by weight of polysiloxane compound having two or more ethylenically unsaturated bonds in one molecule (c) Organic titanate compound (d) Modification comprising organic solvent This is achieved by a method of correcting the surface of a lithographic printing plate requiring no dampening solution, which comprises performing a heat treatment after applying the liquid.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The configuration of the present invention will be described below in detail.

In the present invention, "weight" means "mass".

The polyvalent hydrogen organic polysiloxane of the component (a) used in the present invention is an organic polysiloxane having a group represented by the following general formula (I), wherein the group represented by the general formula (I) May be at the terminal of the molecular chain or in the molecular chain.

[0015]

Embedded image Examples of the organic group other than the group of the general formula (I) include a group having 1 to 3 carbon atoms.
0 or more preferably a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, more preferably a substituted or unsubstituted alkenyl group having 2 to 20 carbon atoms, and a substituted or unsubstituted alkyl group having 5 to 30 carbon atoms more preferably 5 to 20 carbon atoms. Examples include an unsubstituted aryl group, but from the viewpoint of improving the ink repellency, those having a methyl group of 80% or more are particularly preferable. General formula (I)
The molecular weight of the organic polysiloxane having a group represented by is preferably 1,000 to 500,000, and 3,000 to 3
More preferably, the one of 100,000 is used.

The polysiloxane compound having two or more ethylenically unsaturated bonds in one molecule of (b) is a polysiloxane compound having a group represented by the following general formula (II). The group (II) may be at the terminal of the molecular chain or in the molecular chain.

[0017]

Embedded image (Wherein R1 and R2 each have 1 to 30 carbon atoms, more preferably 1
To 20 substituted or unsubstituted alkyl groups having 2 to 2 carbon atoms
It is at least one selected from the group of a substituted or unsubstituted alkenyl group having 2 to 20 carbon atoms, and a substituted or unsubstituted aryl group having 5 to 20 carbon atoms, more preferably 5 to 20 carbon atoms. May be. As the organic group other than the group represented by the general formula (II), a group having 1 to 3 carbon atoms
0 or more preferably a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, more preferably a substituted or unsubstituted alkenyl group having 2 to 20 carbon atoms, and a substituted or unsubstituted alkyl group having 5 to 30 carbon atoms more preferably 5 to 20 carbon atoms. Examples include an unsubstituted aryl group, but from the viewpoint of improving the ink repellency, those having a methyl group of 80% or more are particularly preferable. General formula (II)
The molecular weight of the polysiloxane compound having a group represented by is preferably 1,000 to 500,000, and 3,000 to 3
More preferably, the one of 100,000 is used.

The amount of the polysiloxane compound having two or more ethylenically unsaturated bonds in one molecule is as follows:
(A) 0.1 to 100,00 per 100 parts by weight of component
0 parts by weight, preferably 1 to 10,000 parts by weight, more preferably 10 to 5,000 parts by weight. 0.1 used
If the amount is less than 100 parts by weight or more than 100,000 parts by weight, the strength of the silicone rubber coating obtained by the addition reaction tends to decrease.

From the viewpoint of the adhesion of the plate surface correcting liquid to the printing plate surface, etc., the number of moles of the group of the general formula (I) in the component (a) is 1.1 of the number of moles of the group
It is preferably used so as to be at least twice, more preferably at least 1.2 to 10 times.

The molecular structure of component (a) and component (b) may be linear, cyclic or branched, and it is preferred that at least one of the molecular weights exceeds 1,000 from the viewpoint of rubber properties.

As the organic titanate compound of the component (c), tetrabutyl titanate, tetra-2-ethylhexyl titanate, triethanolamine titanate, tetraisopropenyloxy titanate, titanium bis (triethanolamine) diisopropoxide, titanium diisopropoxy (Bis-2,4-pentanedionate),
Titanium ethoxide, titanium diisopropoxide bis (ethyl acetoacetate), titanium 2-ethylhexoxide, titanium isobutoxide, titanium isopropoxide, titanium lactate, titanium methoxide, titanium methoxypropoxide, titanium methyl Phenoxide, titanium n-monooxide, titanium n-propoxide, titanium triisopropoxide tri-n-butylstannoxide and the like are exemplified. These titanium-based catalysts include polyvalent hydrogen organopolysiloxane and 1
It promotes an addition reaction with a polysiloxane compound having two or more ethylenically unsaturated bonds in a molecule, and enables curing of a silicone rubber coating at a low temperature.

The amount of the organic titanate compound used is not particularly limited, but is preferably 100 parts by weight or less, more preferably 1 to 80 parts by weight, per 100 parts by weight of the component (a).
Parts by weight.

Regarding the kind of the organic solvent of the component (d),
There is no particular limitation as long as it dissolves the above components (a) to (d), but those having good wettability when applied to the plate surface and those having a low boiling point are preferred. Although the amount of use is not particularly limited,
In order to obtain a good coating thickness, the organic solvent is (a) component 1
The amount is preferably 100 to 5,000 parts by weight, more preferably 500 to 3,000 parts by weight, based on 00 parts by weight.

In addition to these compositions, a dimethylpolysiloxane having a terminal trimethylsilyl group, a silicone oil formed by copolymerization of phenylmethylpolysiloxane, and the like may be added. Further, in order to improve rubber elasticity, a known filler such as silica may be added. Further, a known dye may be added so that the corrected portion can be seen at a glance.

[0025] The above-described plate surface correcting solution for a lithographic printing plate requiring no dampening solution is applied to a portion to be corrected on the lithographic printing plate requiring no dampening solution, and then heated to form a silicone rubber film. Let it.

Various methods can be adopted for the method of storing and applying the plate surface correction liquid. For example, a method of impregnating a bundle of fibers such as a brush in a container like an inkwell and applying it, a method of applying it by impregnating it into a cloth, a nonwoven fabric, a pad, etc., a method of sucking and dropping with a dropper, a sign pen The method of filling and using as ink, and the method of applying by spraying into a spray can, etc. are listed.However, from the point of ease of application, etc., it is applied by impregnating into a bundle of brushes and other fibers. It is preferable to use a method of performing the above.

At the time of application, the composition hardly cures in an atmosphere at room temperature, so that the brush durability is good and the application over a large area is easy.

When the correction liquid is applied and then heated, it quickly cures, and can eliminate scratches, pinhole-shaped defects, defects based on film edges, or normal image portions.

The heating temperature is preferably 50 ° C. or more, more preferably 50 ° C. to 140 ° C., from the viewpoint of the time required for the film to cure. As a method of heating,
For example, there are a method of heating in an oven and a method of blowing hot air using a dryer or the like.

[0030]

The present invention will be described in more detail with reference to the following examples.

Examples 1-2 A positive film was placed on a positive type lithographic printing plate precursor TAP manufactured by Toray Industries Co., Ltd., which did not require dampening solution, and brought into close contact with each other by vacuum. A metal halide lamp (Idol Fin 2000 manufactured by Iwasaki Electric Co., Ltd.) was used. , UV meter (UV-402A manufactured by Oak Manufacturing Co., Ltd.)
And image exposure was performed at an illuminance of 11 mW / cm ² for 120 seconds. Subsequently, the laminated film of the exposed plate was peeled off and developed using an automatic developing machine for a positive type waterless planographic printing plate manufactured by Toray Industries, Inc., and an image faithfully reproducing the positive film was obtained. .

Approximately 200 mL of a plate surface correcting solution comprising an addition type silicone rubber composition having the following composition was placed in a glass bottle having a diameter of 10 cm. Using a paint brush, a plate surface correcting solution having the following composition was applied on a solid image area of 30 cm × 40 cm of the developed printing plate. During the application, the correction liquid in the bottle and the correction liquid adhering to the tip of the brush did not gel, and the brush durability was good. This printing plate was heat-treated in an oven at 80 ° C. for 90 seconds to cure the coating film. 100 parts by weight of a Si-H group-containing cross-linking agent represented by the following (III) (number average molecular weight: about 10,000): dimethyl polysiloxane having a vinyl group at both ends (number average molecular weight: about 4,000) X parts by weight (X Are shown in Table 1.) Tetrabutyl titanate 5 parts by weight Isopar G (mixture of petroleum hydrocarbons: Exxon Chemical Co., Ltd.) 2,000 parts by weight

Embedded image This printing plate was attached to the Heidelberg GTO printing press,
TOYOING ULTRA T manufactured by Toyo Ink Co., Ltd.
When printing was performed with UK AQUALES G black ink, good prints were obtained for printing of 80,000 sheets or more.

Further, a container (0.5 mm thick, made of high-density polyethylene (density 0.958))
1.5 g in a volume of 2 mL) and sealed, 40 ° C / 80R
When the plate was stored in a constant temperature and humidity chamber of H% for 2 weeks and evaluated after forced storage, the plate surface correction liquid was still liquid.
No gel was found inside.

COMPARATIVE EXAMPLE 1 In Example 1, the amount of dimethylpolysiloxane having a vinyl group at both ends (number average molecular weight: about 4,000) was set at 0.1.
A printing durability test of the erased portion and a forced preservation test of the solution at 40 ° C./80 RH% for 2 weeks were performed in the same manner as in Example 1 except that the amount was changed to 01 parts by weight. As a result, the brush durability was good, but the printing durability was 500 to 1,000 sheets. The plate surface correction liquid remained liquid even after forced storage, and no gel was found therein.

Examples 3 and 4 The same procedures as in Example 1 were carried out except that a plate surface correcting solution comprising an addition type silicone rubber composition having the following composition was used. / 80R
A forced preservation test of the solution was performed at 2% H for 2 weeks. 100 parts by weight of a Si-H group-containing cross-linking agent represented by the following formula (IV) (number average molecular weight: about 10,000) X part by weight of dimethylpolysiloxane having both ends a vinyl group (number average molecular weight: about 10,000) X is shown in Table 1.) Tetrabutyl titanate 5 parts by weight Isopar G (mixture of petroleum hydrocarbons: Exxon Chemical Co., Ltd.) 2,000 parts by weight

Embedded image As a result, the brush durability was good, the printing durability was 80,000 sheets or more, and the plate surface correction liquid remained liquid even after forced storage, and no gel was found therein.

Examples 5 to 6 In the same manner as in Example 3, except that dimethylpolysiloxane having a number-average molecular weight of about 110,000 and both ends of which were vinyl groups was used in the plate surface correcting solution of Example 3, A printing durability test and a forced preservation test of the solution at 40 ° C./80 RH% for 2 weeks were performed. 100 parts by weight of a Si-H group-containing cross-linking agent represented by the formula (IV) (number average molecular weight: about 10,000) Dimethyl polysiloxane having a vinyl group at both ends (number average molecular weight: about 110,000) X parts by weight (X Are shown in Table 1.) Tetrabutyl titanate 5 parts by weight Isopar G (mixture of petroleum hydrocarbons: Exxon Chemical Co., Ltd.) 2,000 parts by weight As a result, the brush durability is good and the printing durability is good. More than 80,000 sheets were obtained, and the plate surface correction liquid remained liquid even after forced storage, and no gel was found in the liquid.

COMPARATIVE EXAMPLE 2 In Example 5, the amount of dimethylpolysiloxane having vinyl groups at both ends (number average molecular weight: about 110,000) was changed to 5
In the same manner as in Example 5 except that the amount was set to 00,000 parts by weight, the printing durability test of the erased portion and 40 ° C / 80 RH%
The solution was subjected to a weekly forced preservation test. As a result, the brush durability was good, but the printing durability was 500 to 1,000 sheets. The plate surface correction liquid remained liquid even after forced storage, and no gel was found therein.

Table 1 shows the results of Examples 1 to 6 and Comparative Examples 1 and 2.

[0039]

[Table 1] As shown in the results of Table 1, in Examples 1 to 6 in the claims of the present invention, the storage stability and brush durability are good,
A large area can be corrected using a brush or the like. Further, it is possible to obtain a film having excellent printing durability without lowering the curing speed.

On the other hand, Comparative Examples 1 and 2 of the present invention, which were out of the scope of the claims, had low strength of the silicone rubber film and poor press life.

Examples 7 to 12 In the same manner as in Example 3 except that the amount of tetrabutyl titanate and the amount of Isopar G used in the plate surface correcting solution of Example 3 were changed, the printing durability test of the erased portion and the 40 ° C
A forced preservation test of the solution at / 80 RH% for 2 weeks was performed. 100 parts by weight of a Si-H group-containing cross-linking agent represented by the formula (IV) (number average molecular weight: about 10,000) 100 parts by weight of dimethylpolysiloxane having both ends a vinyl group (number average molecular weight: about 110,000) X part by weight of titanate Isopar G (mixture of petroleum hydrocarbons: Exxon Chemical Co., Ltd.) Y part by weight (X and Y are shown in Table 2) As a result, the brush durability is good and the printing durability is good. More than 80,000 sheets were obtained, and the plate surface correction liquid remained liquid even after forced storage, and no gel was found in the liquid.

Table 2 shows the results of Examples 7 to 12.

[0043]

[Table 2] As shown in the above Table 2, in Examples 7 to 12 in the claims of the present invention, the storage stability and brush durability are good, and large areas can be corrected using a brush or the like. Further, it is possible to obtain a film having excellent printing durability without lowering the curing speed.

Examples 13 to 14 The same procedures as in Example 3 were carried out except that dimethylpolysiloxane having a methyl group at each end (average molecular weight: about 15,000) was added to the plate surface correcting solution of Example 3. A printing durability test of the erased portion and a forced preservation test of the solution at 40 ° C./80 RH% for 2 weeks were performed. 100 parts by weight of a Si-H group-containing cross-linking agent represented by the formula (IV) (number average molecular weight: about 10,000) 100 parts by weight of dimethylpolysiloxane having both ends a vinyl group (number average molecular weight: about 110,000) X is a methyl group (average molecular weight: about 15,000) X parts by weight (X is shown in Table 3) Tetrabutyl titanate 5 parts by weight Isopar G (mixture of petroleum hydrocarbons: Exxon Chemical ( )) 2,000 parts by weight As a result, the brush durability is good, the printing durability is 80,000 sheets or more, and this plate surface correction liquid remains liquid even after forcible preservation, and there is no gel substance in it. I couldn't see it.

Example 15 A printing durability test of an erased portion and a printing test of 4 were performed in the same manner as in Example 3 except that titanium isobutoxide was used in place of tetrabutyl titanate in the plate surface correcting solution of Example 3.
A forced preservation test of the solution at 0 ° C./80 RH% for 2 weeks was performed. 100 parts by weight of a Si—H group-containing cross-linking agent represented by the formula (IV) (number average molecular weight: about 10,000) 100 parts by weight of dimethylpolysiloxane having both ends a vinyl group (number average molecular weight: about 110,000) Butoxide, 5 parts by weight Isopar G (mixture of petroleum hydrocarbons: Exxon Chemical Co., Ltd.) 2,000 parts by weight As a result, brush durability is good and printing durability is 80,000 sheets or more. The plate surface correction liquid remained liquid after the forced preservation, and no gel was found therein.

Example 16 The same method as in Example 3 was carried out, except that 5 parts by weight of titanium isobutoxide was added to the plate surface-correcting solution of Example 3, and a printing durability test of the erased portion and a temperature of 40 ° C./80 RH% for 2 weeks were performed. The liquid was subjected to a forced preservation test. 100 parts by weight of a Si-H group-containing cross-linking agent represented by the formula (IV) (number average molecular weight: about 10,000) 100 parts by weight of dimethylpolysiloxane having both ends a vinyl group (number average molecular weight: about 110,000) Titanate 5 parts by weight Titanium isobutoxide 5 parts by weight Isopar G (mixture of petroleum hydrocarbons: Exxon Chemical Co., Ltd.) 2,000 parts by weight As a result, brush durability is good and printing durability is 80,000 sheets As described above, the plate surface correction liquid remained liquid even after forced storage, and no gel was found in the liquid.

Example 17 To the plate surface correcting solution of Example 3, 3 parts by weight of platinum chloride was added, and 1 part of tetracyclo (methylvinyl) siloxane was further added.
A printing durability test of the erased portion and a forced storage test of the solution at 40 ° C./80 RH% for 2 weeks were performed in the same manner as in Example 3 except that the parts by weight were added. 100 parts by weight of a Si-H group-containing cross-linking agent represented by the formula (IV) (number average molecular weight: about 10,000) 100 parts by weight of dimethylpolysiloxane having both ends a vinyl group (number average molecular weight: about 110,000) 5 parts by weight titanate 3 parts by weight platinum chloride 1 part by weight tetracyclo (methylvinyl) siloxane 1 part by weight Isopar G (mixture of petroleum hydrocarbons: Exxon Chemical Co., Ltd.) 2,000 parts by weight The printing power was 80,000 sheets or more, and the plate surface correction liquid remained liquid even after forced preservation, and no gel was found therein.

Example 18 In the same manner as in Example 3, except that 1 part by weight of crystal violet was added to the plate surface correcting solution of Example 3, a printing test of the erased portion and a solution at 40 ° C./80 RH% for 2 weeks were performed. Was tested. 100 parts by weight of a Si-H group-containing cross-linking agent represented by the formula (IV) (number average molecular weight: about 10,000) 100 parts by weight of dimethylpolysiloxane having both ends a vinyl group (number average molecular weight: about 110,000) Titanate 5 parts by weight Crystal violet 1 part by weight Isopar G (mixture of petroleum hydrocarbons: Exxon Chemical Co., Ltd.) 2,000 parts by weight As a result, the brush durability is good and the printing durability is 80,000 sheets or more. The plate surface correction liquid remained liquid even after forced storage, and no gel was found therein.

Example 19 The same method as in Example 3 was carried out except that Isopar E was used instead of Isopar G in the plate surface correcting solution of Example 3, and a printing durability test of the erased portion and 40 ° C./80 RH% 2 were carried out.
The solution was subjected to a weekly forced preservation test. 100 parts by weight of a Si-H group-containing cross-linking agent represented by the formula (IV) (number average molecular weight: about 10,000) 100 parts by weight of dimethylpolysiloxane having both ends a vinyl group (number average molecular weight: about 110,000) 5 parts by weight of titanate Isopar E (mixture of petroleum hydrocarbons: Exxon Chemical Co., Ltd.) 2,000 parts by weight As a result, the brush durability is good, the printing durability is 80,000 sheets or more, and the plate surface is modified. The liquid remained liquid after forced storage, and no gel was found in the liquid.

Example 20 The same method as in Example 3 was carried out except that n-hexane was used instead of Isopar G in the plate surface correcting solution of Example 3, and the printing durability test of the erased portion and 40 ° C./80 RH% 2 were carried out.
The solution was subjected to a weekly forced preservation test. 100 parts by weight of a Si-H group-containing cross-linking agent represented by the formula (IV) (number average molecular weight: about 10,000) 100 parts by weight of dimethylpolysiloxane having both ends a vinyl group (number average molecular weight: about 110,000) 5 parts by weight of titanate 2,000 parts by weight of n-hexane As a result, the brush durability is good, the printing durability is 80,000 sheets or more, and the plate surface correction liquid remains liquid even after forced storage. No gel was found at the same time.

Table 3 shows the results of Examples 13 to 20.

[0052]

[Table 3] As shown in Table 3, in Examples 13 to 20 in the claims of the present invention, the storage stability and brush durability are good, and a large area can be corrected using a brush or the like. Further, it is possible to obtain a film having excellent printing durability without lowering the curing speed.

Examples 21 to 24 In the plate surface correcting solution of Example 3, the same procedures as in Example 3 were carried out except that the heat treatment temperature and time were changed. Was subjected to a forced storage test.

As a result, the brush durability was good and the printing durability was 8
The number of prints was 10,000 or more, and the plate surface correction liquid remained liquid even after forced storage, and no gel was found in the liquid.

Example 25 The same method as in Example 3 was carried out except that the plate surface correction liquid of Example 3 was subjected to a heat treatment for 120 seconds with hot air (about 80 ° C.) from a dryer, and a printing durability test of an erased portion and 40 ° C. / 8
A forced preservation test of the solution at 0 RH% for 2 weeks was performed.

As a result, the brush durability was good and the printing durability was 8
The number of prints was 10,000 or more, and the plate surface correction liquid remained liquid even after forced storage, and no gel was found in the liquid.

Example 26 A negative film was superposed on a negative type lithographic printing plate precursor TAN manufactured by Toray Industries, Inc., and was brought into close contact with a vacuum, and UV was applied using a metal halide lamp (Idol Fin 2000 manufactured by Iwasaki Electric Co., Ltd.). Meter (UV-402A manufactured by Oak Works)
And image exposure was performed at an illuminance of 11 mW / cm 2 for 60 seconds.
Then, the laminated film of the exposed plate was peeled off and developed using an automatic developing machine for a negative waterless planographic printing plate manufactured by Toray Industries, Inc., and an image faithfully reproducing the negative film was obtained. .

In the same manner as in Example 3 except that the plate surface correction liquid of Example 3 was used, the printing durability test of the erased portion and 40 ° C./8
A forced preservation test of the solution at 0 RH% for 2 weeks was performed.

As a result, the brush durability was good and the printing durability was 8
The number of prints was 10,000 or more, and the plate surface correction liquid remained liquid even after forced storage, and no gel was found in the liquid.

Comparative Example 3 Erasing was carried out in the same manner as in Example 3 except that platinum chloride was used instead of tetrabutyl titanate and 1 part by weight of tetracyclo (methylvinyl) siloxane was added to the plate surface correcting solution of Example 3. Printing test and 40 ℃ / 8
A forced preservation test of the solution at 0 RH% for 2 weeks was performed. 100 parts by weight of a Si-H group-containing cross-linking agent represented by the formula (IV) (number average molecular weight: about 10,000) 100 parts by weight of dimethylpolysiloxane having both ends a vinyl group (number average molecular weight: about 110,000) 3 parts by weight Tetracyclo (methylvinyl) siloxane 1 part by weight Isopar G (mixture of petroleum hydrocarbons: Exxon Chemical Co., Ltd.) 2,000 parts by weight As a result, the brush durability was good, but the printing durability was poor. Thousand to two
It was a thousand. The plate surface correction liquid remained liquid even after forced storage, and no gel was found therein.

Comparative Example 4 In the same manner as in Example 3, except that tetrabutyl titanate was removed from the plate surface correcting solution of Example 3, the printing durability test of the erased portion and the test of the solution at 40 ° C./80 RH% for 2 weeks were performed. A forced storage test was performed. 100 parts by weight of a Si-H group-containing cross-linking agent represented by the formula (IV) (number average molecular weight: about 10,000) 100 parts by weight of dimethylpolysiloxane having both ends vinyl groups (number average molecular weight: about 110,000) Isopar G (Mixture of petroleum hydrocarbons: Exxon Chemical Co., Ltd.) 2,000 parts by weight As a result, brush durability is good, and this plate surface correction liquid remains liquid even after forced preservation, and gel material is not contained. Although not seen, the coating film did not cure when heated.

Comparative Example 5 On a printing plate exposed and developed in the same manner as in Example 1, a plate surface correcting solution comprising a condensed silicone rubber composition having the following composition was applied, and heated at 23 ° C./50 RH% for 90 seconds. Air dried and cured. Thereafter, in the same manner as in Example 1, the printing durability test of the erased portion and the temperature of 40 ° C./80 RH% 2
The solution was subjected to a weekly forced preservation test. 100 parts by weight of dimethylpolysiloxane having hydroxyl groups at both ends (average molecular weight of about 22,000) 100 parts by weight of dimethylpolysiloxane having an average molecular weight of about 15,000 at both ends of methyl group 40 parts by weight of methyltriacetoxysilane Dibutyltin acetate 5 parts by weight Isopar G (mixture of petroleum hydrocarbons: Exxon Chemical Co., Ltd.) 1,000 parts by weight n-butyl acetate 200 parts by weight As a result, while applying, the correction liquid in the bottle, The correction liquid adhering to the bristle tip of the brush both gelled, and the brush durability was poor. The printing durability was 80,000 or more. However, when this plate surface correction solution was forcibly stored, a gel was observed.

Results of Examples 21 to 27 and Comparative Examples 3 to
Table 4 shows the results of No. 5.

[0064]

[Table 4] As described above, when the condensed silicone rubber solution of Comparative Example 5 was used, although the adhesion to the image area was excellent and a coating excellent in printing durability was provided, the storage stability of the correction liquid
The brush life was poor.

In Comparative Examples 3 and 4 outside the scope of the claims of the present invention, the adhesion to the image area was poor, the printing durability was low, and the cured film was insufficient.

On the other hand, the present invention uses an addition type silicone rubber and uses a titanium catalyst, so that crosslinking proceeds only by heating, storage stability and brush durability are good, and a large area using a brush or brush is used. Can be modified. Further, since there is no leaving group as in the case of the condensation type silicone rubber solution, there is little off-flavor.

[0067]

According to the present invention, since the plate surface correcting liquid of the lithographic printing plate requiring no dampening solution is constituted as described above, the gel is not gelled in the container during distribution and storage, and the storage stability can be used for a long time. have. Further, it is suitable for correcting a relatively large area using a brush or a brush, and has excellent brush durability in the air. In addition, it has excellent adhesion to the image area, does not cause printing stains, and gives a film having excellent printing durability, and has a curing speed equivalent to that of the conventional condensation type.

Claims (3)

[Claims] A lithographic printing plate having a silicone rubber layer as an ink repellent layer, wherein the lithographic printing plate requires no dampening solution and is used to correct an image area to a non-image area. (B) 0.1 to 100,000 parts by weight of a polysiloxane compound having two or more ethylenically unsaturated bonds in one molecule (c) Organic titanate compound (d) Organic A plate surface correcting liquid for a lithographic printing plate requiring no dampening solution, which is a solution comprising a solvent. 2. A method for repairing a lithographic printing plate requiring no dampening solution, comprising heating after applying the correcting solution according to claim 1. 3. The method according to claim 2, wherein the heating temperature is set to 50 ° C. or higher.