JPS62257169A - Photoengraving method - Google Patents

Abstract

PURPOSE:To eliminate scumming and to improve the sensitization of an image part by coating an aq. soln. contg. a specific sulfate or the salt thereof on a lithographic printing plate after development and subjecting the plate to a burning process in the presence of such compd. CONSTITUTION:The sulfate expressed by ROSO3M or the salt thereof is used as the processing soln. to be coated in the lithographic printing plate prior to the burning process. In the formula, R denotes a straight chain or branched chain alkyl group of 4-11C or alkenyl group, M denotes a hydrogen atom, alkali metal, ammonium, amine. The need for making counter-etching after the burning process is thereby eliminated and the generation of scumming in the non-image part is nevertheless obviated. The lithographic printing plate having the high sensitization of the image part and excellent printing resistance power is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of the Invention] The present invention relates to a plate-making method using a photosensitive lithographic printing plate, and in particular, after imagewise exposure and development of a photosensitive lithographic printing plate using a metal as a support, burning is performed. This relates to a plate-making method when used as a plate.

[Prior art]

Lithographic printing is a printing method that skillfully takes advantage of the property that water and oil essentially do not mix.The printing plate surface has two areas: one area that accepts water and repels oil-based ink, and the other area that repels water and accepts oil-based ink. 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 the property of repelling water and accepting oil-based ink after image formation.

There are two types of photosensitive compositions used to create lithographic printing plates: positive type and negative type.
Those made of quinonediazide compounds are widely used.

Positive-working photosensitive lithographic printing plates are made by coating an 0-quinonediazide compound alone or in a mixture with an alkali-soluble resin such as novolak-type phenol (E1 fat, cresol resin, etc.) on a suitable support such as metal or plastic. When exposed to actinic light through a transparency, the O-quinonediazide compound in the exposed area decomposes and becomes alkali-soluble, so it is easily removed by an alkaline aqueous solution, giving a positive image. When a support is used, the hydrophilic surface of the support is exposed in the area removed by the alkaline aqueous solution, so this area accepts water and repels ink.On the other hand, the area remaining as an image is lipophilic and , apply ink.

On the other hand, many negative-working, photosensitive compositions use diazonium salts, azide compounds, or photopolymerizable compounds, and such photosensitive compositions are used alone or mixed with additives such as suitable resins, Painted on top. When a support with a hydrophilic surface is used, the unexposed areas are removed by a developer,
The hydrophilic surface of the support is exposed and this area receives water and repels ink. On the other hand, the portion that is cured by exposure and remains as an image upon development is lipophilic and accepts ink.

When the lithographic printing plate created in this way is printed on an offset printing machine, beautiful printed matter can be obtained. Planographic printing plates made from such photosensitive planographic printing plates can produce tens of thousands of beautiful prints by appropriately selecting the composition of the support and the photosensitive layer coated thereon.
In particular, by using a grained and anodized aluminum plate as a support, it is possible to obtain beautiful printed matter of up to 10,000 sheets.

However, there is also a desire to obtain many more printed sheets from a single printing plate. In this case, a photosensitive lithographic printing plate using a metal plate such as aluminum or zinc as a support is exposed and developed in the usual manner, and then heated at high temperature (so-called burning treatment) to strengthen the image area. The method is valid.

That is, by performing the burning process, the number of printed matter obtained from one lithographic printing plate can be increased several times compared to the case where the burning process is not performed.

Furthermore, when printing with a special printing ink containing a large amount of components that dissolve the image on the printing plate, such as ultraviolet curing ink or low-temperature drying ink, the printing plate made by the normal method without burning will cause the image area to disappear. The elution is severe and the number of prints is significantly lower than when using normal ink, but when the burning treatment is applied, the solvent resistance of the image area is greatly improved, so the above special printing ink is However, you can get a sufficient number of prints.

However, the non-image area of the printing plate (i.e., the area where the hydrophilic support surface is exposed by development), which was hydrophilic before the treatment, loses its hydrophilicity and becomes receptive to printing ink due to the burning treatment. As a result, stains (so-called background stains) occur in the background of printed matter. Heating to an extent that does not cause such background smearing does not produce a burning effect, and image reinforcement is not achieved. Therefore, it is necessary to carry out a surface preparation process to prevent staining of the non-image area caused by the burning process. Various proposals have been made in the past as a surface smoothing treatment used before and/or after this burning treatment step.

For example, after the burning process, a fluoride aqueous solution such as hydrofluoric acid, borohydrofluoric acid, silicohydrofluoric acid, etc. However, these fluorides are classified as poisonous and deleterious substances and pose many problems in terms of pollution control.

Furthermore, when this surface smoothing treatment is applied, the metal surface of the support corrodes, making the surface more susceptible to scratches and becoming more susceptible to abrasion. ) is lost, background smearing occurs, and further printing is no longer possible.

In addition, as a processing method to prevent the hydrophilicity of the non-image area from decreasing before the burning process, Japanese Patent Laid-Open No. 51
Publication No. 34001 discloses treatment with an aqueous solution of an organic sulfonic acid salt such as alkylnaphthalene sulfonic acid sorter, alkyldiphenyl ether sodium sulfonate, and lithium nitrate before burning. Among these, aqueous solutions of salts of organic sulfonic acids such as sodium alkylnaphthalene sulfonate and sodium alkyl diphenyl ether sulfonate have extremely high foaming properties.
It is unsuitable for use in the spray circulation type processors that are currently widely used, and has the drawback that it cannot automate the plate-making process. Furthermore, when treated with a solution containing lithium nitrate and burned, the prevention of scumming was not sufficient. Furthermore, Japanese Patent Publication No. 55-28062 discloses a method of treating with an aqueous solution containing sublimable boric acid and its salts before burning, and then performing burning in the presence of the compound. Prevention of scumming was not sufficient. In particular, scumming may occur due to conditions such as washing with water and gumming after burning treatment, i.e., if washing with water is insufficient or if a dextrin-based gum solution with weak hydrophilicity is used as the desensitized gum solution. The drawback was that it was easy to occur. Furthermore, JP-A No. 52-6205 discloses that water-soluble ta+2y substances such as gum arabic, cellulose ether, and polyacrylic acid, and/or borates, phosphates, sulfates, alkali metals, and alkaline earths are added before the burning process. Treatment with an aqueous solution of water-soluble inorganic salts such as halides of similar metals has been shown, but even with this method, it is not always possible to completely prevent background stains, and in particular, it is not possible to completely prevent background stains. When using an aqueous solution of a water-soluble polymer such as, there is a drawback that it becomes difficult for the image area to receive ink during printing, resulting in so-called inking failure. Furthermore, JP-A No. 57-52057 discloses a method of treating with an aqueous solution containing a carboxyl group-containing amine or a salt thereof, such as ethylenediaminetetraacetic acid or hydroquinoalkylethylenediaminetriacetic acid, before the burning treatment. There is. however,
This method also could not be said to be sufficiently effective in preventing background stains.

[Purpose of the invention]

An object of the present invention is to provide an improved plate-making method that includes a burning process. More specifically, it is an object of the present invention to provide a plate-making method including a burning process, which can produce a lithographic printing plate that is free from scumming and has excellent oil sensitivity in image areas.

Another object of the present invention is to provide a plate-making method including a burning process that can be automated by using a spray circulation type processing machine or the like.

[Structure of the invention]

The present inventor has solved the above problems by using an aqueous solution containing a specific sulfuric acid ester or its salt as a treatment liquid (hereinafter referred to as a burning pretreatment liquid) applied to a lithographic printing plate before burning treatment. We found that the target was achieved.

In the present invention, a sulfuric ester represented by general formula (I) or a salt thereof is used.

RO3○5M... (I) (in the formula, R
is a linear or branched alkyl group or alkenyl group having 4 to 11 carbon atoms, and M represents a hydrogen atom, an alkali metal, ammonium, or an amine. ) These compounds include, for example, 2-ethylbutyl sulfate, tetraamyl sulfate, n-heptyl sulfate, methylamyl sulfate, 3-heptyl sulfate, 1-octyl sulfate, 2-octyl sulfate, 3.5. 5-trino-7-ruhequinyl nysdel sulfate, 2-ethylhexyl sulfate, n-
Examples include denyl sulfate and undecyl sulfate either singly or in a mixture of two or more.

Salts include sodium salts, potassium salts, lithium salts, ammonium salts, amine salts, etc. of these compounds.

The above compounds can be used alone or in combination of two or more, and O, 1 to 30% by weight, more preferably 0.5 to 20% by weight, based on the total weight of the burning pretreatment liquid according to the present invention. It can be contained within a range of %.

The burning pretreatment liquid used in the present invention may further contain various additives.

Examples of such additives include surfactants, various salts, acids, alkalis, and the like.

The surfactant helps the burning pretreatment liquid used in the present invention to be uniformly applied to the surface of the lithographic printing plate, and also partially suppresses the occurrence of stains in non-image areas due to the burning process. There is. Preferred surfactants are anionic surfactants, among them alkylbenzene sulfonates, alkyldiphenyl ether disulfonates, alkylnaphthalene sulfonates, aldehyde condensates of alkylnaphthalene sulfonates, α-olefin sulfonate
Particularly preferred are sulfonic acid group-containing surfactants such as , -t, etc., and sulfate ester-based surfactants such as lauryl sulfate, polyoxyethylene alkylphenyl ether sulfate, and polyoxyethylene alkylphenyl ether sulfate. The amount of surfactant in the burning pretreatment liquid is approximately 0.05% by weight.
It is suitable to contain it in a range of about 10% by weight, preferably 0.1 to 5 weights.

Furthermore, an acid, alkali or salt can be used for pH adjustment in the burning pretreatment liquid used in the present invention, if necessary. As acids it is possible to use mineral acids and organic acids. For example, nitric acid, sulfuric acid, phosphoric acid, mineral acids, organic acids such as citric acid, phosphoric acid, M acid, tartaric acid, acetic acid, malic acid, potassium salts, lithium salts of these acids,
Examples include sodium salts or ammonium salts, alkali metal hydroxides, carbonates, and carbonated rock salts.

These acids, salts, and alkalis have a pll of 2 to 10, preferably 3 to 10 pll, of the burning pretreatment liquid used in the present invention.
It can be contained in an amount within a range of 8.

Furthermore, the burning pretreatment liquid used in the present invention contains water-soluble polymeric substances such as gum arabic, dextrin, carboquine methylcellulose, and polyacrylic acid, polymethacrylic acid, and salts thereof (such as sodium salts); Colorants, antifoaming agents, wetting agents, preservatives, etc. may also be added.

In the present invention, the burning pretreatment liquid is used to image-expose a photosensitive lithographic printing plate, develop it, wash it with water if necessary, and then remove unnecessary portions for printing with a correction agent. After it is created, it is dried if necessary and applied before the burning process. Methods for this include coating the planographic printing plate with a sponge or absorbent cotton impregnated with the pretreatment liquid, immersing the printing plate in a vat filled with the treatment liquid, and applying the coating automatically. Application with a coater etc. is applied. Also, after applying, use a squeegee or
To make the application amount uniform with a squeegee roller,
Gives more favorable results.

The lithographic printing plate coated with the burning pretreatment liquid is dried if necessary, and then heated to a high temperature in a burning processor (for example, Burning Processor 1300 sold by Fuji Photo Film ■).Heating in this case Although the temperature and time depend on the types of components forming the image, they are preferably in the range of 180 to 300°C for 1 to 20 minutes.

The burn-treated lithographic printing plate can be subjected to conventional treatments such as washing with water and gumming, if necessary. It is possible to omit so-called desensitization treatment such as.

The plate making method according to the present invention can be applied to various photosensitive planographic printing plates, but in particular, photosensitive planographic printing plates (printing plates to which photosensitization has been imparted in advance) using an aluminum plate as a support, PS
called a version. ) can be suitably used. Such P
A preferred S version is, for example, British Patent No. 1.350.
521, a photosensitive layer made of a mixture of a diazo resin (a salt of a condensate of p-diazodiphenylamine and rose formaldehyde) and shellac is provided on an aluminum plate, British Patent No. 1 .460.9
78 and No. 1.505.739, consisting of a mixture of diazo at t+ and a polymer having hydroxyethyl methacrylate units or hydroxyethyl acrylate units as main repeating units. Negative type 28 plate, such as one in which the layer is provided on an aluminum plate, and JP-A-50-12580
This includes a positive type 25 plate in which a photosensitive layer made of a mixture of an 0-quinonediazide photosensitive material and a novolak type phenol resin is provided on an aluminum plate as described in Japanese Patent No. 6. 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. No. 4,072,528 A PS plate in which a photosensitive layer of a photopolymerizable photopolymer composition as described in the specifications of No. 1 and No. 4.072.527 is provided on an aluminum plate,
British Patent No. 1.235.281 and British Patent No. 1.495
．． Also preferred is a PS plate in which a photosensitive layer made of a mixture of azide and a water-soluble polymer is provided on an aluminum plate as described in each specification of No. 861. Among these PS plates, a particularly preferred PS plate to be used in the plate making method of the present invention is a positive type 25 plate having a photosensitive layer consisting of an 0-naphthoquinonediazide compound and a 7-borac resin, and is disclosed in US Patent No. 4. This is explained in detail in the specification of No. 259.434, column 3, line 2 from the bottom to column 6, line 14 east.

〔Effect of the invention〕

According to the plate making method of the present invention, there is no need to perform a surface smoothing treatment after the burning treatment. Despite this, a lithographic printing plate with excellent printing durability and high oil sensitivity in the image area without staining in the non-image area can be obtained. Moreover, since the burning pretreatment liquid used in the present invention has a low foaming property, it can be applied to planographic printing plates using a spray circulation type processing machine, which has great advantages such as automation of plate making work.

Moreover, according to the plate making method of the present invention, desensitization treatment after burning can be omitted. After the burning process, it not only has the effect of not causing background smudges even if it is printed after being placed on the plate for a long time, but it also has the effect of preventing scratches from forming on the plate surface, thus making it difficult for scratches and stains to occur. .

〔Example〕

Hereinafter, the present invention will be explained in more detail with reference to Examples.

Example 1 Naphthoquinone (I) of 1,5-dihydroxynaphthalene
, 2)-Diazide (2)-5-sulfonic acid ester (2 parts by weight) and 4 parts by weight of novolak type cresol-formaldehyde resin were dissolved in 100 parts by weight of ethylene glycol monomethyl ether. Next, this solution was coated on a grained aluminum plate with a thickness of 0.24 mm so that the weight after drying was 2.5 g/m''. After placing the printing plate in close contact with the transparency and exposing it for 30 seconds from a distance of 1 m using a 3KW metal halide lamp, 5% by weight of sodium silicate was applied.
It was developed by immersing it in an aqueous solution for about 1 minute. Next, after washing with water,
A burning pretreatment liquid having the following composition was applied and dried.

Sodium hexyl sulfate 200 parts by weight Rumphytic acid (50%) 30 Potassium hydroxide lO Pure water
940 The printing plate thus treated was heated in a commercially available burning processor for 26 hours.
Heated for 6 minutes at a temperature of 0°C.

After cooling, it was gummed, and when this printing plate was attached to an offset printing machine and printed, beautiful prints were obtained in just a few prints, and when printing continued, 150,000 beautiful prints were awarded first prize. .

Comparative Example 1 A lithographic printing plate that had been treated under exactly the same conditions as in Example 1 up to one development treatment was treated with a 4% by weight ammonium borate aqueous solution instead of the burning pretreatment liquid used in Example 1, and was subjected to the same burning process. Processed and gummed. When this lithographic printing plate was used for printing, smearing occurred in the halftone dot image in a portion of the shadow from the beginning of printing, and it was necessary to remove the dirt from the smeared area with a plate cleaner.

Example 2 Graining and anodizing treatment (Anodizing was carried out in I5% sulfuric acid at a current density of 1.6 ampere/dm' for 2 minutes.)
A positive photosensitive lithographic printing plate was prepared by applying the same light wave as in Example 1 onto an aluminum plate having a thickness Q of 3 mm.

This was exposed to light for 40 seconds using a 3KW metal halide lamp from a distance of 1 m with a transparent hot water surface in close contact with the surface, and then developed by immersing it in a 7% by weight aqueous solution of sodium silicate for about 1 minute.

This lithographic printing plate is processed using an automatic through-type paring processor [
Process 1, 1. Co., Ltd., application of burning pre-treatment liquid,
Burning and gumming are performed continuously. ] was continuously processed. Here, the burning temperature settings are preheating 150℃,
Post-heating was carried out at 240° C., and the passing time through the filtration was about 3 minutes, and the burner pretreatment liquid used had the following composition.

Sodium hequinyl sulfate 15 parts by weight Salt Decyl sulfate sodium salt 5 Potassium hydroxide 12 Pure water
When the lithographic printing plate obtained by burning 943 parts by weight was directly attached to an offset printing machine and printed, beautiful prints were obtained in just a few prints, and 300,000 prints were obtained by continuing to print. Ta.

Comparative Example 2 The development process was carried out in the same manner as in Example 2, and the treatment liquid in the burning processor was treated with an 8ffii% aqueous solution of sodium alkyl diphenyl ether sulfonate, and the other conditions were the same as in Example 2. Significant foaming occurred from the spray pipe in the area where the liquid was applied and its tank, and the liquid overflowed from the tank, necessitating the operation of the automatic treatment machine to be stopped.

Example 3 In the same manner as in Example 1, except that an aqueous solution having the following composition was used as the burning pretreatment liquid, the same results as in Example 1 were obtained.

Sodium octyl sulfate 10 parts by weight Salt Sodium decyl sulfate 3 Phytic acid (50%) 30 Lithium hydroxide
10 〃Dipotassium citrate
10 Pure water
937 Example 4 By the condensation polymerization of acetone and pyrogallol as described in Example 1 of U.S. Pat. No. 3,635,709 (!
) broken polyhydroxyphenyl and naphthoquinone-1,
2-Diazide (2)-5-sulfonic acid ester 4-1 and 7-borac type cresol-form, aldehyde! ) and 4 parts by weight of fat were dissolved in 100 parts by weight of ethylene glycol monomethyl ether to give a dry weight of 2.5 parts to the grained and anodized aluminum plate used in Example 2.
g/m' to prepare a positive type 1 photosensitive lithographic printing plate.

After this positive photosensitive lithographic printing plate was exposed, developed and washed with water in the same manner as in Example 1, a pre-burning treatment solution having the following composition was applied, and then a burning treatment was performed at 260° C. for 5 minutes.

Malic acid 30 Phytic acid (50%) 10 Potassium hydroxide
13 Glycerin
10 Pure water
927 When the obtained lithographic printing plate was mounted on an offset printing machine without gumming and printed, beautiful printed matter was obtained in just a few prints, and it was continued as it was for two
We were able to obtain 00,000 prints.

Example 5 A solution was prepared by dissolving 20 parts by weight of shellac and 3 parts by weight of a diazo resin obtained by condensing p-)luenesulfonate of p-diazodiphenylamine with formaldehyde in 80 parts by weight of dimethylformamide. On the other hand, a grained aluminum plate was heated to 80°C with 0.2% potassium zirconium fluoride.
After being immersed in an aqueous solution for 3 minutes to make it hydrophilic,
Wash with water, dry, and add the above prepared solution to a weight of 2.0 after drying.
It was applied so that it was g/m'.

The negative photosensitive lithographic printing plate thus obtained was exposed through a transparent negative for 30 seconds from a distance of 1 m using a 3KW metal halide lamp, immersed in an aqueous solution of 20% by weight of isopropyl alcohol for about 1 minute, and then surfaced with absorbent cotton. When rubbed lightly, only the unexposed areas were peeled off and removed, exposing the surface of the support.

After washing with water, apply the burning pretreatment liquid used in Example [
After drying and performing a burning process under the same conditions as in Example 1, it was installed on an offset printing machine and printed. Beautiful prints were obtained in about 10 sheets from the beginning of printing, and when printing continued as it was, the results were as follows. We were able to obtain 150,000 pieces of printed matter with almost no change in condition.

Example 6 A pumice/water slurry and a nylon brush were used to sand the grain, anodized (anodized in 20% sulfuric acid at 2 A/dm' for 2 minutes), and then treated with 2.5 wt. of sodium silicate at 70°C. An aluminum plate with a thickness of 0.3 mm was prepared by treating it with a % aqueous solution for 1 minute.

A photosensitive liquid having the following composition was applied to this aluminum plate so that the weight after drying was 2.0 g/m''.

Methyl cell solve 95mj' water

5 ml of the thus obtained negative photosensitive planographic print was exposed through a transparent negative to a 3 KW metal halide lamp from a distance of 1 m for 30 seconds, and developed using the following developer.

Benzyl alcohol 30ml 1' diethanolamine 10g Sodium sulfite 5g Water
11 After washing with water, apply the burning pre-treatment liquid used in Example 2, dry it, perform the burning treatment under the same conditions as Example 2, and then install it on an offset printing machine and print. I was able to obtain beautiful prints, and when I continued printing, I was able to produce 200,000 prints with almost the same tone as the first print.

Example 7 In the same manner as in Example 6, the following photosensitive solution was applied to a plate that had been anodized and treated with sodium silicate in a grain chamber using a dry type f13.
．． It was coated to a coating weight of Og/m' and dried at 100°C for 2 minutes.

Fuclocyanine Blue 3g Ethylene dichloride 500g 2-methoxyethyl acetate 500g After drying, a 3% by weight aqueous solution of polyvinyl alcohol was applied to the surface of the photosensitive layer to a dry weight of 1.5 g/m'' and dried.

This plate was exposed and developed in the same manner as in Example 6. After washing with water, apply the burning pretreatment liquid used in Example 4,
After performing a burning process under the same conditions, the paper was attached to an offset printing machine and printed, and beautiful printed matter was obtained after just a few sheets.

Claims (1)

[Scope of Claims] In a plate-making method in which a photosensitive lithographic printing plate is subjected to image exposure and development and then subjected to a burning treatment, a sulfuric ester or sulfuric ester salt represented by the following general formula (I) is used after development and before the burning treatment. 1. A plate-making method comprising applying an aqueous solution containing the compound and performing a burning treatment in the presence of the compound. ROSO_3M...(I) (wherein, R is a linear or branched alkyl group or alkenyl group having 4 to 11 carbon atoms, and M represents a hydrogen atom, an alkali metal, ammonium, or an amine. )