JPH1184684A - Burning pretreating liquid for lithographic printing plate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a lithographic printing plate which has low foaming property, no contamination on the base and excellent sensitivity of an image part by incorporating a specified org. silicon compd. and an anion surfactant into a treating liquid. SOLUTION: This treating liquid contains at least one kind of compd. expressed by formula I or formula II and an anion surfactant. In formula I and formula II, A represents formula III and B represents formula IV, x is an integer 1 to 20, y is an integer 1 t 10, and R<5> , R<6> are hydrogen atoms or 1 to 10C alkyl group. The sequences of -AO- and -BO- as the repeating units may be at random, or same units may be continuously bonded. In formula III, R<1> , R<2> are 1 to 3C alkyl groups. In formula IV, R is 1 to 3C alkyl group, R<4> is a hydrogen atom or 1 to 3C alkyl group, X is methylene, ethylene, propylene or trimethylene, m is an integer 1 to 20.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pretreatment solution for burning which is used after exposing and developing a photosensitive lithographic printing plate and before performing a burning process.

[0002]

2. Description of the Related Art Lithographic printing is a printing method that skillfully utilizes the property that water and oil are not essentially mixed. The printing plate surface receives water and repels oil-based ink and water. The former is a non-image area and the latter is an image area. Therefore, the photosensitive composition used for preparing a lithographic printing plate is required to have a property of repelling water and receiving oily ink after image formation. A photosensitive composition used for preparing a lithographic printing plate includes a positive type and a negative type, and the positive type photosensitive composition generally comprises an o-quinonediazide compound. The positive-type photosensitive lithographic printing plate is an o-quinonediazide compound alone or mixed with an alkali-soluble resin such as a novolak-type phenolic resin or cresol resin and coated on a suitable support such as metal or plastic, and is transparent. When exposed to actinic rays through a positive image, the exposed portion of the o-quinonediazide compound decomposes and changes to alkali-soluble, and is easily removed by an aqueous alkali solution to give a positive image. Therefore, when a support having a hydrophilic surface is used, the portion removed with the aqueous alkali solution exposes the hydrophilic surface of the support, and this portion receives water and repels the ink. On the other hand, the portion remaining as an image is lipophilic and accepts ink. On the other hand, negative photosensitive compositions often use a diazonium salt, an azide compound or a photopolymerizable compound, and such a photosensitive material is used alone or mixed with an additive such as a suitable resin, and is coated on a support. Is painted on. When a support having a hydrophilic surface is used, the unexposed portion is removed with a developer to expose the hydrophilic surface of the support, and this portion accepts water and repels the ink. On the other hand, the portion that is cured by exposure and remains as an image during development is lipophilic and accepts ink.

When the lithographic printing plate thus prepared is printed by an offset printing machine, a beautiful printed matter can be obtained. A lithographic printing plate prepared from such a photosensitive lithographic printing plate can provide tens of thousands of beautiful printed matter by appropriately selecting the composition of a support and a photosensitive layer applied thereon. In particular, by using a grained and anodized aluminum plate as a support, it is possible to obtain up to 100,000 beautiful printed matters. However, there is also a demand for obtaining a larger number of printed materials from one printing plate. In such a case, a photosensitive lithographic printing plate using a metal plate such as aluminum or zinc as a support is exposed and developed by a usual method, and then heated at a high temperature (so-called burning treatment) to strengthen the image area. Is valid. That is, by performing the burning process, the number of prints obtained from one lithographic printing plate can be increased several times as compared with the case where the burning process is not performed. Furthermore, when printing with a special printing ink that contains many components that dissolve the image on the printing plate, such as UV-curable ink or low-temperature drying ink, the image portion is eluted in the printing plate made by the usual method without burning treatment. Although the number of printings is significantly lower than when ordinary inks are used, the burning resistance greatly improves the solvent resistance of the image area. A sufficient number of prints can be obtained.

However, the non-image area of the printing plate which was hydrophilic before the processing (that is, the area where the surface of the hydrophilic support was exposed by development) is subjected to the burning treatment so that the hydrophilic property is lost. Since the ink is accepted, a stain (so-called background stain) occurs on the background of the printed matter. If the heating is performed to such an extent that the background stain does not occur, the burning effect cannot be obtained, and the image cannot be reinforced. Therefore, it is necessary to always perform surface adjustment processing to prevent the non-image portion from being stained due to the burning processing. Conventionally, various proposals have been made as surface conditioning treatments used before and / or after the burning treatment step. Prior to the burning treatment, Japanese Patent Application Laid-Open No. 51-34001 discloses a treatment method for preventing the hydrophilicity of the non-image portion from being reduced.
For example, it is disclosed that the treatment is carried out before burning with an aqueous solution of sodium alkylnaphthalenesulfonate, sodium alkyldiphenylethersulfonate and lithium nitrate. Of these, when an aqueous solution of an organic sulfonic acid salt such as sodium alkylnaphthalenesulfonate or sodium alkyldiphenylethersulfonate is used, the foaming properties are remarkably high, so that it can be used in a spray circulation type processing machine that is currently widely used. Was inadequate and could not automate the plate making operation. In addition, when treated with a solution containing lithium nitrate and burned, prevention of background fouling was not sufficient.

Further, DE 2530422 C2 and JP-A-64-4
No. 9687 discloses a perfluoroalkyl sulfonate, a perfluoroalkyl carboxylate, a perfluoroalkyl phosphate, a perfluoroalkyltrimethylammonium chloro compound, a perfluoroalkyl alcohol, a perfluoroalkylpolyoxyethylene oxide adduct and the like. Is described. However, these compounds are disadvantageous in that when they are subjected to the burning treatment, their ability to prevent the non-image area from becoming dirty and the halftone dot shadow area from becoming desensitized are poor, so that stains and ink blemishes tend to occur. Also, when applying using an automatic applicator, a large amount of an antifoaming agent is required because the foam easily forms and overflows from the tank. In addition, the foam of the foamed fine particles collects on the image area, and when dried and subjected to a burning treatment, fine ring-shaped marks become uneven in ink, so-called poor ink deposition, and 500 or more sheets must be printed to obtain normal printing. There is a problem that a normal printed matter cannot be obtained.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide an improved burning pretreatment solution which does not have the above-mentioned disadvantages. More specifically, an object of the present invention is to provide a burning pretreatment liquid having a low foaming property, and further, to obtain a lithographic printing plate having high printing durability, which does not generate background stain, and has excellent oil sensitivity in an image area. It is to provide a burning pretreatment liquid that can be used. Another object of the present invention is to provide a burning pretreatment liquid which can be preferably applied to a lithographic printing plate using a spray circulation type processing machine or the like.

[0007]

Means for Solving the Problems The inventors of the present invention added a specific organic silicon compound and an anionic interface to a processing solution (hereinafter, referred to as a burning pretreatment solution) applied to a lithographic printing plate before performing a burning process. By containing an activator,
The inventors have found that the above objects can be achieved, and have completed the present invention. Accordingly, the present invention provides the following general formula (I)
And a burning pretreatment liquid for a lithographic printing plate, comprising at least one compound represented by the formula (II) and an anionic surfactant.

[0008]

Embedded image

[Where A is

Embedded image (Wherein, R ¹ and R ² represent an alkyl group having 1 to 3 carbon atoms), and B is

[0010]

Embedded image

Wherein R ³ represents an alkyl group having 1 to ³ carbon atoms, R ⁴ represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, and X represents methylene, ethylene, propylene or trimethylene. And m represents an integer of 1 to 20), x represents an integer of 1 to 20, and y represents 1 to 1.
Represents an integer of 0, R ⁵ and R ⁶ represent a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, and is a repeating unit −
The order of AO- and -BO- may be random or the same may be continuous. ]

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION The following are specific examples of the organosilicon compound represented by the above general formula (I) or (II) used in the present invention.

[0013]

Embedded image

The compound represented by the general formula (I) or (II) is not limited to the above, but a compound having a solubility in water of 1% or less can be preferably used. Among the above organosilicon compounds (a) to (d), in particular, (a) and
(d) can be preferably used. These compounds are generally available on the market, and commercial products can be used in the present invention. Two or more of these compounds can be used in combination. In the burning pretreatment liquid of the present invention, the content of at least one compound represented by the general formula (I) or (II) is based on the total weight of the burning pretreatment liquid.
0.001 to 3.0% by weight is suitable, and preferably 0.001 to 3.0% by weight.
5 to 1.0% by weight. If the content is less than 0.001% by weight, the coated surface quality deteriorates, and it takes time to obtain a normal printed matter,
In addition, bubbles may be spilled from the stock tank of the automatic coater, making it impossible to make a plate. On the other hand, 3.0% by weight
Exceeding the formula (3), spot-like unevenness occurs in the coating surface quality, and this unevenness may hinder ink deposition.

[0015] The burning pretreatment liquid of the present invention also contains an anionic surfactant. Such a surfactant assists in evenly applying the burning pretreatment liquid to the surface of the lithographic printing plate, and also has a part of an effect of suppressing the generation of stains in a non-image area due to the burning treatment. Examples of the anionic surfactant used in the present invention include alkyl benzene sulfonate, alkyl diphenyl ether disulfonate, alkyl naphthalene sulfonate, aldehyde condensate of alkyl naphthalene sulfonate,
α-olefin sulfonate, sulfonic acid group-containing surfactant such as alkyl sulfonate, lauryl sulfate, polyoxyethylene alkyl ether sulfate,
Sulfate surfactants such as polyoxyethylene alkylphenyl ether sulfate are particularly preferred. Two or more anionic surfactants may be used in combination. The anionic surfactant is suitably contained in the range of 0.05 to 30% by weight, and preferably in the range of 0.1 to 20% by weight, based on the total weight of the burning pretreatment liquid.

The burning pretreatment liquid of the present invention may further contain various acids, alkalis and salts for adjusting pH. Mineral acids and organic acids can be used as the acid. For example, nitric acid, sulfuric acid, mineral acids such as phosphoric acid, citric acid, succinic acid, oxalic acid, tartaric acid, acetic acid, malic acid, phytic acid, organic phosphonic acid, p-toluenesulfonic acid, organic acids such as xylenesulfonic acid, Potassium, lithium, sodium or ammonium salts of these acids;
Alternatively, hydroxides, carbonates, hydrogencarbonates and the like of alkali metals may be mentioned. These acids, salts and alkalis adjust the pH of the burning pretreatment solution of the present invention to 2 to 10, preferably 3 to 10.
-8 can be contained.

Further, the burning pretreatment liquid of the present invention includes:
A polymer compound having a film forming property can also be added. For example, gum arabic, starch derivatives (eg, dextrin, enzymatically decomposed dextrin, hydroxypropylated enzymatically degraded starch, carboxymethylated starch, phosphorylated starch, etc.), alginates, and fibrin derivatives (eg, carboxymethylcellulose, carboxyethylcellulose, hydroxyethylcellulose) Natural products such as methylcellulose, hydroxypropylcellulose, hydroxypropylmethylcellulose, and their modified glyoxals) and their modified products, polyethylene glycol and its copolymers, polyvinyl alcohol and its derivatives, polyvinylpyrrolidone, polyacrylamined and its copolymers. Polymer, polyacrylic acid and its copolymer, vinyl methyl ether / maleic anhydride copolymer, vinyl acetate / maleic anhydride copolymer It compounds such as polystyrene sulfonic acid and copolymers thereof. These polymer compounds may be used alone or in combination of two or more. The range of use is suitably from 0.0001 to 3% by weight based on the total weight of the burning pretreatment liquid.

The pretreatment solution for burning of the present invention may further contain a preservative, an antifoaming agent, a coloring agent and the like. Preferable preservatives include phenol or derivatives thereof, formalin, imidazole derivatives, sodium dehydroacetate, 4-isothiazolin-3-one derivatives,
Benztriazole derivatives, amidizing anidine derivatives, quaternary ammonium salts, derivatives such as pyridine, quinoline, guanidine, etc., thiocarbamic acid derivatives, diazines, triazole derivatives, oxazoles, oxazine derivatives, 2-bromo-2-nitropropane-1,3- Diols and the like. The preferable addition amount is an amount that exerts a stable effect on bacteria, mold, yeast and the like, and varies depending on the kind of bacteria, mold and yeast, but is 0.001 to 3.0 with respect to the burning pretreatment liquid. It is preferably in the range of% by weight, and it is preferable to use two or more kinds in combination so as to exert effects on various molds and bacteria. In addition, a silicone antifoaming agent is preferable as the antifoaming agent. Specifically, any of an emulsified dispersion type and a solubilized type can be used. The amount used is 0.001 to 0.001% of the total weight of the burning pretreatment liquid.
0.1% by weight is suitable. The colorant is used to impart a desired color tone to the burning pretreatment liquid of the present invention and to give visual contrast, and can be selected from a wide range of dyes. Particularly preferred dyes are blue,
Indicator dyes having dyeings such as purple, red, and yellow exhibit excellent effects. For example, dyes such as crystal violet, safranin, brilliant blue, malachite green, and acid rhodamine B can be suitably used.

The burning pretreatment liquid of the present invention is obtained by subjecting a photosensitive lithographic printing plate to image exposure, development and, if necessary, washing with water.
Unnecessary parts for printing are removed with a correction agent, and a printing plate with no room for further correction is created.
Apply before burning. As a method, a sponge or absorbent cotton impregnated with a burning pretreatment liquid is applied on a lithographic printing plate, or a printing plate is immersed in a vat filled with a treatment liquid, or is applied automatically. Coating with a coater or the like is applied. Further, making the amount of the coating uniform with a squeegee or a squeegee roller after the coating gives more preferable results. The lithographic printing plate coated with the burning pretreatment liquid is dried, if necessary, and then burned (for example, a burning processor 13 sold by Fuji Photo Film Co., Ltd.).
00). The heating temperature and time in this case depend on the type of the component forming the image,
The temperature is preferably in the range of 180 to 300 ° C. for 1 to 20 minutes. The lithographic printing plate subjected to the burning treatment can be subjected to a conventional treatment such as washing with water or gumming as needed.

The burning pretreatment liquid of the present invention can be applied to various lithographic printing plates. In particular, a photosensitive lithographic printing plate using an aluminum plate as a support (a printing plate to which photosensitivity has been previously added, and a PS plate, ). A preferred PS plate is a photosensitive layer comprising a mixture of a diazo resin (a salt of a condensate of p-diazodiphenylamine and paraformaldehyde) and shellac as described in, for example, British Patent No. 1,350,521. On an aluminum plate, a diazo resin and a polymer having a hydroxyethyl methacrylate unit or a hydroxyethyl acrylate unit as a main repeating unit as described in UK Patent Nos. 1,460,978 and 1,505,739. Negative PS plates such as those having a photosensitive layer comprising a mixture of
No. 806 discloses a positive PS plate in which a photosensitive layer comprising a mixture of an o-quinonediazide photosensitive material and a novolak-type phenol resin is provided on an aluminum plate. Further, a PS plate in which a photosensitive layer of a photocrosslinkable photopolymer is provided on an aluminum plate, as specifically shown in U.S. Pat. No. 3,860,426, U.S. Pat.
PS plate in which a photosensitive layer of a photopolymerizable photopolymer composition as described in the specifications of 4,072,528 and 4,072,527 is provided on an aluminum plate, UK Patent No. 1,235,
Also preferred are PS plates having a photosensitive layer comprising a mixture of azide and a water-soluble polymer provided on an aluminum plate as described in the specifications of JP-A-281 and JP-A-1,495,861. Among these PS plates, a particularly preferred PS plate is a positive PS plate having a photosensitive layer composed of an o-naphthoquinonediazide compound and a novolak resin, and is disclosed in U.S. Pat.
No. 434, from column 3 bottom line to column 6 line 14 is described in detail.

[0021]

The use of the pre-burning treatment liquid of the present invention eliminates the need for surface conditioning after the burning treatment. Nevertheless, a lithographic printing plate having no stain on the non-image area, high oil sensitivity in the image area, and excellent printing durability can be obtained. In addition, since the burning pretreatment liquid of the present invention has a low foaming property, it can be applied to a lithographic printing plate using a spray circulation type processing machine, and there is a great advantage that the plate making operation can be automated.

[0022]

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

Example 1 100 parts by weight of naphthoquinone- (1,2) -diazide (2) -5-sulfonic acid ester of 1,5-dihydroxynaphthalene and 4 parts by weight of a novolak-type cresol-formaldehyde resin in 100 parts by weight of ethylene Dissolved in glycol monomethyl ether. Next, 0.24 thickness
This solution was applied on a grained aluminum plate having a thickness of 2.5 mm to a dry weight of 2.5 g / m ² . The positive photosensitive lithographic printing plate thus prepared was brought into close contact with the transparent positive and exposed for 30 seconds with a 3 KW metal halide lamp from a distance of 1 m, followed by sodium silicate 5% by weight.
It was immersed in an aqueous solution for about 1 minute and developed. Then after washing with water,
A burning pretreatment liquid having the following composition was applied by a coater and dried. Phytic acid (50%) 5.0 g Sodium dodecylbenzenesulfonate (60% aqueous solution) 192 g 4-isothiazolin-3-one derivative 0.1 g 2-bromo-2-nitropropanediol 0.1 g The above organosilicon compound (a 0.28 g Sodium hydroxide Adjust the pH to 6.0 to 6.5.

The printing plate thus treated was heated in a commercial burning processor at a temperature of 260 ° C. for 6 minutes. After cooling, the surface of the plate was observed. As a result, there were almost no thick coating portions unique to the coater on the left and right sides of the plate, and a good surface quality burning treatment was performed. Then, GU-7
(Gum solution manufactured by Fuji Photo Film Co., Ltd.) was applied, and this printing plate was attached to an offset printing machine, Heidelberg SOR-M, and printing was performed. 200,000 sheets were printed.

[0024]

EXAMPLE 2 Example 1 on a 0.3 mm thick aluminum plate which was grained and anodized (anodized in 15% by weight sulfuric acid at a current density of 1.6 amps / dm ² for 2 minutes).
A positive photosensitive lithographic printing plate was prepared by applying the same photosensitive liquid as described above. A transparent positive image is adhered to this, and from a distance of 1 m 3
After exposing for 40 seconds with KW's metal halide lamp,
It was immersed in a 7% by weight aqueous solution of sodium silicate for about 1 minute for development. This lithographic printing plate is subjected to continuous application of a pretreatment solution for burning, burning and gumming by an automatic integrated burning processor [Process Materials Co., Ltd.]. ] Was continuously processed. Here, the burning temperature is set to 150
℃, post-heating 240 ℃, the passage time of the furnace is about 3 minutes,
The burning pretreatment liquid used had the following composition.

Ammonium citrate 5.0 g Sodium alkyl diphenyl ether sulfonate (50% aqueous solution) 140.0 g 4-isothiazolin-3-one derivative 0.2 g Benzoic acid methyl ester 0.2 g The above organosilicon compound (d) 0.2 g pure water Make the whole 1000 ml. As in Example 1, the coated surface quality after burning was observed. As a result, good surface quality without coating unevenness was obtained. When the printing plate was directly attached to a printing machine Heidelberg SOR-M and printed, a beautiful printed matter was obtained on several sheets from the start of printing, and 300,000 sheets of printed matter could be continuously obtained.

[0026]

Example 3 Example 1 of US Pat. No. 3,635,709
Polyhydroxyphenyl and naphthoquinone obtained by condensation polymerization of acetone and pyrogallol
4 parts by weight of 1,2-diazide (2) -5-sulfonic acid ester and novolak-type cresol formaldehyde resin 4
Parts by weight of ethylene glycol monomethyl ether 10
0 parts by weight, and the dry weight was 2.5 g / m ^{2 on} the grained and anodized aluminum plate used in Example ^2.
And a positive photosensitive lithographic printing plate was prepared. This positive photosensitive lithographic printing plate was exposed, developed and washed with water under the same conditions as in Example 1, then a burning pretreatment liquid having the following composition was applied, and then subjected to a burning treatment at 260 ° C. for 5 minutes.

2-phosphonobutane-1,2,4-tricarboxylic acid (50%) 5.0 g sodium isopropylnaphthalenesulfonate 50 g sodium metaxylenesulfonate 10.0 g 1,1-dibromo-1-nitro-2-ethanol 0 0.2 g of the above organosilicon compound (c) 0.2 g of sodium hydroxide Adjust the pH to 6.0 to 6.5.

The lithographic printing plate obtained had a uniform and good coating surface quality. When printing was performed by attaching it to a printing machine Heidelberg SOR-M without gumming, beautiful prints were obtained on several sheets from the start of printing, and 200,000 sheets of prints could be continuously obtained.

[0029]

COMPARATIVE EXAMPLE A burning pretreatment liquid having a composition obtained by removing the organosilicon compound from each of the burning pretreatment liquids of Examples 1 to 3 above was prepared, and was used as Comparative Examples 1 to 3, which were the same as in Examples. To obtain a lithographic printing plate. The following items were tested for the performance of each burning pretreatment liquid and the performance of each lithographic printing plate. The results are summarized in Table 1. Coated surface quality Plate 600 × 500cm Size was set to half the non-image area to determine the coatability. ○ ‥‥ Good △ ‥‥ Slight unevenness × ‥‥ Some unevenness The number of papers used until normal printing The number of papers required for normal printing with the ink roller (ink adhesion). Stain on Non-Image Area Ink adhesion on non-image areas of up to 3000 prints was observed. ○ ‥‥ Good △ ‥‥ Slightly poor × ‥‥ Poor

[0030]

[Table 1] Example Comparative Example 1 2 3 1 2 3 Coated surface quality ○ ○ ○ △ × × ─────────────────────────── 22 Until normal printing 22 25 25 270 145 220 Number of sheets used ─────────────────────────────汚 れ Stain on non-image area ○ ○ ○ △ △ △ ───────────────────────────────── ──

Claims (1)

[Claims] 1. A lithographic printing plate burning pretreatment solution containing at least one compound represented by the following general formula (I) or (II) and an anionic surfactant. Embedded image [Wherein A is Wherein R ¹ and R ² each represent an alkyl group having 1 to 3 carbon atoms, and B represents (Wherein, R ³ represents an alkyl group having 1 to ³ carbon atoms,
R ⁴ represents a hydrogen atom or an alkyl group having 1 to 3 carbon atoms, X represents methylene, ethylene, propylene or trimethylene, and m represents an integer of 1 to 20. ) And x
Represents an integer of 1 to 20, y represents an integer of 1 to 10,
R ⁵ and R ^{6 each} represent a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, and repeating units —AO— and —BO—
May be random or the same may be continuous. ]