JPS60168694A - Treating liquid for blank printing plate - Google Patents

Abstract

PURPOSE:To enhance scumming-preventive property and plate-placing property, by incorporating at least one selected from phytic acid, a metallic salt thereof and a phytic acid derivative together with sorbitan and/or sorbitol and a fluoro surfactant into the titled liquid. CONSTITUTION:The treating liquid for a blank printing plate is prepared by adding (A) at least one selected from phytic acid, a metallic salt thereof and a phytic acid derivative, (B) sorbitan and/or sorbitol and (C) a fluoro surfactant to water. The component (C) is a surfactant having the so-called fluorocarbon chain as a water-repellent group, and may be of the anion type, the cation type or the like. The amount of the component (C) is 4-200pts.wt. per 1,000pts.wt. of the liquid. In using the component (A), it is necessary to maintain the pH of the treating liquid in a neutral or acidic region, and a preferable pH value is 3-6.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application II-) The present invention relates to improvement of a desensitizing treatment liquid used for each nu lithographic printing original plate. More specifically, the present invention relates to an improvement in a fat treatment solution containing phytic acid, phytic acid, or a derivative thereof.

(Prior art) As is well known in the past, offset printing original plates based on the basic principle of electrophotography are made of a paint Tr: photosensitive layer in which a photoconductive substance such as zinc oxide, which is an inorganic fine powder, is dispersed in a binder. The printing plate is coated on a support and then developed with an oil-sensitive developer to obtain a printing plate.

In addition, using an original plate in which an image-receiving layer in which inorganic pigments are dispersed in resin is coated on a sheet-like base material, a separately created electrophotographic image can be transferred onto this layer, or it can be directly written or typed with oil-based ink. The so-called direct image offset master, which prints and creates a printing plate, is also well known.

However, when performing offset printing using these original plates, a desensitizing treatment is required to make the non-image areas on the plate hydrophilic, and in particular, it is difficult to stably obtain clear prints without background smudges over several dozen sheets. For this reason, this desensitization treatment is an extremely important step.

The processing liquid for desensitization treatment, that is, the etchant, is particularly required to have (1) background smudge prevention (no background smear occurs from the beginning to the end of printing); (2) 1
These include one-plate properties (the desensitized state is maintained even if the printing plate after etching is left as it is for at least several minutes and then printed, and printing without background smearing is possible).

In particular, due to printing operations, it is often necessary to first etch a large number of sheets and then print using them, and in this case, an etchant with good printing properties is required. Furthermore, even if the plate after etching is immediately mounted on a printing press, some time may elapse due to adjustments and the like before printing begins, and in this case too, plate setting performance is important.

In addition, automatic printing machines have become popular in recent years, and in these cases as well, it usually takes several minutes from etching to the time when printing actually begins with the plate, and plate placement is still required.

At present, the following types of desensitizing liquids are known:

(1) Those whose main constituents are organic acids, inorganic acids, their salts, etc. (for example, Japanese Patent Publication No. 43-28404) (2) Those whose main constituents are ferrocyanate and ferricyanide salts (for example, Japanese Patent Publication No. 28404/1989). No. 39-8416) (3
) The main component is a compound of phytic acid or a salt thereof (for example, JP-A-51-103501).

However, among these, treatment liquids that fall into category (1) have a weak desensitizing ability and cannot be said to be practical. Commercially, processing solutions that fall into category (2) are often used, but they have drawbacks such as ferrocyan ions and 7-elysian ions being unstable to light and heat, and containing cyanide ions. .

(Object of the Invention) The present invention has the drawbacks of the desensitizing liquids (1) and (2), and furthermore, the desensitizing liquid (3) has the following disadvantages:
The purpose of the present invention is to provide a desensitizing treatment liquid with improved scumming prevention properties and plate placement properties.

(Structure of the Invention) The present invention comprises: (5) one or more selected from phytic acid, phytate gold i salt, and phytic acid derivatives; (c) sorbitan and/or sorbitol; 0 fluorine-based surfactant; A printing original plate processing liquid characterized by containing:

(Detailed Description of the Invention) Phytic acid or its salt compounds are all substances that are derived from natural products, and are completely harmful to the human body due to heat. Moreover, its desensitizing power shows the same effect as the conventional treatment solution containing 7 erocyan salts and ferricyan salts, and organic acids,
Compared to treatment solutions containing inorganic acids and their salts as main components, which have a desensitizing power that is hardly practical, the desensitizing power is significantly superior. Further, the hydrophobicity of the image area, that is, the ink receptivity is not hindered at all. Phytic acid, phytic acid metal salts, and phytic acid derivatives react with the photoconductive fine powder component in the photosensitive layer and the fine powder component on the direct image offset master to form hydrophilic and dissolvable compounds on the printing plate. It is thought that this leads to desensitization of the non-image areas.

The phytic acid used in the present invention is a substance also known as inositol hexalinic acid, myo-inositol hexalin r11, etc., and is obtained by desalting phytin, which is contained in large amounts in plant seeds.

Examples of the metal salts of phytic acid used in the present invention include alkali metal salts such as sodium and potassium, alkaline earth metal salts such as calcium, magnesium, and barium, and metal salts such as zinc, aluminum, iron, and titanium. It may be a double salt of

The equivalent ratio of phytic acid and metal ions is 1 for alkali metals.
:1 to 1 : 10 (phytic acid: metal ion), preferably 1:1 to 1 nia, and 1: for other metal ions.
The ratio is 1 to 1:5, preferably 1:1 to 1:3.

In addition, the derivatives of phytic acid used in the present invention include alkyl groups, alkylcarboxine groups, alkylhydroxyl groups, alkylamido groups, alkylamino7 groups, alkyl epoxy groups, ethylene oxide groups, alkoxy groups, acetyl groups, acetamido groups, and amino acid groups. Examples include phytic acid derivatives having one or more substituents such as acrylamide group or acrylamide group. The above substances are, for example, 2-monosodium phytate, 3.5-mo/magnesium phytate, 3,6-dipotassium phytate, phytin 1φ
2-monomethyl ester, phytic acid 5-acetoxy ester, phytic acid 6-methylcarboxyester,
Examples include phytic acid 2-sodium 3,5-magnesium, phytic acid 2-sodium 5-aceto A oxyester, phytic acid 3-potassium 6-methylcarboxyester, etc. Lermo (1) Te is 4c. The present inventors further found that by using sorbitan and/or sorbitol in combination with fluorine-containing surfactant 1, the uniform wettability of the processing liquid to plate C61 was significantly improved as a synergistic effect, and the same effect as that of etching processor 1 was found. However, we have discovered that it is possible to print without background smudges. Also, same 11. It was found that the If\ version performance was also significantly improved. Sorbitan is obtained by intramolecular dehydration of sorbitol (also known as sorbitol). It is usually produced industrially as a mixture of 1,4-sorbitan, 3,6-sorbitan, 1,5-sorbitan, which are one-molecule dehydrates, and 1,4,3,6-sorbitan, which is two-molecule dehydrates. many. Sorbitol is widely distributed in nature and is found in fruits and seaweeds. Pure glucose is a white, odorless, crystalline powder, but an industrial method for producing it by reducing glucose has been established, and it is generally supplied as a concentrated aqueous solution.

The fluorine-based surfactant is a general term for surfactants having a so-called fluorocarbon chain which is fluorinated as a hydrophobic group. Fluorine surfactants, like ordinary surfactants, come in four types: anionic, nonionic, cationic, and amphoteric. and fluoroalkyl (02-C1o) carboxylic acid, heperfluorooctane sulponyl glutamate disodium, 3-
[fluoroalkyl(C6-C11)oxy]-1-alkyl(c3-C4) sodium sulfonate, 3-[ω
-Fluoroalkanoyl (06-(4) -N -x
Sodium thi/l/amino]-1-propanesulfonate, N-(3-(perflumerooctane sulfonamide)
propyl)-N,N-dimethyl-N-carboxymethylene ammonium betaine, fluoroalkyl (011-
C20) Carboxylic acid, perfluoroalkyl carbon #
(C7-C13), perfluorooctane sulfonic acid jetanolamide, perfluoroalkyl N-propyl-N-(2-hydroxyethyl) perfluorooctane sulfonamide, perfluoroalkyl (
C6-C1o) Sulfonamidopropyltrimethylammonium salt, perfluoroalkyl (C4-C12)
N-ethylsulfonylglycine salt (10, phosphorus t9 bis(N-perfluoromerooctylsulfonyl-N-ethylaminoenalne, monoverfluora7rukyl (C4-
C12) Ethyl phosphorus ester, Nato, is particularly suitable as the fluorine-based stabilizing agent in the present invention. One or more selected from phytic acid, phytic metal salts, and phytic acid Jy=vii forms are added to the aqueous solution as a water-soluble compound. The amount added is not limited to ~, but preferably 1,000 to 200 ft- of the fat-filtration treatment liquid in Tokyo,
Particularly preferably 6 to 100 parts by weight, most preferably 20 to 60 parts by weight. As for the upper limit of addition of λ, it can be used in solution form and can be added almost unlimitedly, but as for the lower limit, if it is 4* parts by weight or less per iooo weight part of the desensitizing treatment liquid, the desensitizing power will be significant. It becomes insufficient and becomes impractical. When using phytic acid, phytic acid metal salts, and phytic acid i-conductors, the pH of the desensitizing solution greatly affects the ability to desensitize IJts, so it is necessary to keep it in a neutral to acidic range. Preferably.

It is highly effective in the pH range of 3 to 6, but the optimum pH varies depending on the type of phytic acid or its salt and the type of additive auxiliary agent. Adjustment of pH is carried out by neutralizing with alkali, using the buffering power of inorganic and organic acids and their salts, etc., and by combining sodium hydroxide with acids such as phosphoric acid, formic acid, sucrose, sucrose, succinate, tartaric acid, etc. PH adjustment method is preferred. Both sorbitan and sorbitol are water-soluble, and the amount added to the processing solution can be determined as appropriate without any particular limitations. On the other hand, if the amount is too low, the effects of the present invention may be lost, so it is most desirable to set the amount to 10 to 50 parts per 1000 parts by weight of the processing liquid. The amount of fluorosurfactant to be added may be determined as appropriate within the range of its solubility, and it is usually used in the range of 0.018B to lθ2 in 1000 weight 1 part of the processing solution. The amount ranges from 0.05 part to 1 part per 1000 parts. When using a fluorine-based surfactant, it may be added directly to the processing solution, but in the case of IT+, it is diluted in water or alcohol before being added. The pure concentration of the treatment liquid, which is the sum of the components of phytic acid and/or its salt, sorbitan and/or sorbitol, and fluorosurfactant, is usually used in the range of 2% to 20%. It is most preferably in the range of 5% to 10%.

Conventionally, inorganic or organic resistant agents or salts thereof have been added as auxiliary additives and bombarding agents to the desensitizing solution, and alcohol has been added to the desensitizing solution to improve its adhesion to the coated surface. In addition, hydrophilic polymeric substances such as gum arabic, Na salt of carboxymethylcellulose, gelatin, and polyvinyl alcohol are used in combination to coat the lipid surface of the offset printing plate with a hydrophilic thin film and increase printing durability. It is also well known that It is also well known to use a rust preventive agent, preservative, etc. in combination. In the composition according to the present invention, there is no problem even if these substances are used in combination.

In addition, when printing, it goes without saying that if the desensitizing liquid of the present invention is diluted with water to a certain amount, it can also be used as a dampening solution.

Example 1 Phytic acid 40. A 10% NaOH aqueous solution was added dropwise to an aqueous solution of li+water 3001 to give a pH of 5.0. To this was added sorbitan 10.9 and a fluorine surfactant (manufactured by 3M, Florado FC-430) 0.
Dissolve 5.9 and add water to make a total of 10009.

Example 2 A 10% aqueous NaOH solution was added dropwise to an aqueous solution of 300 g of phytic acid monosodium salt 459 water to adjust the pH to 5.0. Add to this 10 g of sorbitan and 0.5 fluorine surfactant (manufactured by 3M, Florado FC-430).
g) Dissolve i and add water to make a total of 1000p.

Example 3 Phytic acid 309 Phytic acid monocalcium salt 20 g Water 10% aqueous NaOH solution was added dropwise to an aqueous solution of 300 g to adjust the pH to 5.0. 15 g of sorbitol, 5y1 of isopropyl alcohol, and 0.5 g of a fluorine-based surfactant (Florado I''C-430, manufactured by 3M) were dissolved in this, water was added, and the whole was mixed with iodine.

Let it be g.

Example 4 A product prepared in the same manner as in Example 1 except that phytic acid-resistant mo/methyl ester was used in place of phytic acid.

(Comparative Example 1) In Example 1, the total weight was 1000 g without adding sorbitan and fluorine-based surfactant.

(Comparative Example 2) In Example 1, only sorbitan was excluded, and the rest was prepared in the same manner as in Example 1.

(Comparative Example 3) A sample was prepared in the same manner as in Example 1 except that only the fluorosurfactant was not added.

A printing test was conducted on each of the above sides as follows. First, a commercially available offset master (Itic Co., Ltd., trade name: Blue Label) was made into a plate using an Iticic 175 plate making machine. This plate was treated with the above-mentioned processing solutions either by impregnating absorbent cotton and applying it manually (hand etching) or by applying it using an etching processor manufactured by Itic Co., Ltd. Next, this was printed using a Ryobi 2800 type printing machine, and stains on the printed matter were observed.

2,000 sheets of each were printed, and the condition of background stains from the first sheet to the last was judged, and the results are summarized in Table 1.
It is.

Table 1 (Effects of the invention) The desensitizing treatment liquid of the present invention is not a sham that can be used for various lithographic printing original plates to stably provide clear printed matter without background smearing, but is particularly required for printing work. This has an excellent effect on plate placement properties.

Patent applicant: Oji Paper Co., Ltd. Agent Masaaki Kobayashi

Claims (1)

[Scope of Claims] (a) Phytic acid, gold phytate f[, one or more selected from phytic acid derivatives] sorbitan and/or sorbitol 0 fluorine-based surfactant, characterized by containing: Processing liquid for printing original plates.