JPS63134293A - Desensitizer for lithographic printing plate - Google Patents

Abstract

PURPOSE:To remove toxicity and the necessity of professional skill for adjusting the amount of supply by preparing a desensitizer for a lithographic printing plate containing either of two kinds of water soluble surface active agents represented by specific formulas. CONSTITUTION:An anion surface active agent or the like is allowed to contain a surface active agent represented by a formula I or II [R1 and R3 represent hydrogen atom, alkyl group, aryl group or alkenyl group, R2 alkyl group or aryl group, (m) and (p) integers not less than 1, (n) and (q) 0 or integers not less than 1, and M alkaline metal or NHR4R5R6(R4, R5 and R6 represent hydrogen atom or hydrocarbon group)] to prepare a desensitizer for a lithographic printing plate. In this case, the content of the surface active agent represented by the formula I or II is preferably 0.0005 - 5 % by weight. As a selection criterion for dampening water, it is preferable to have 25 - 50 dyn/cm surface tension.

Description

[Detailed Description of the Invention] [Technical Field] The present invention relates to a desensitizing agent for lithographic printing plates,
The present invention relates to a desensitizing agent for lithographic printing plates that can be used as warming water for lithographic printing plates by further diluting with water.

[Conventional technology]

Lithographic printing is a printing method that skillfully takes advantage of the property that water and oil essentially do not mix, and the printing plate surface has two areas: one area that accepts water and repel oil-based ink, and the other area that repels water and accepts oil-based ink. It consists of two areas, the former being a non-image area and the latter being an image area. The desensitizing agent expands the surface chemical difference between the image area and the non-image area by wetting the non-image area with dampening water containing the desensitizing agent, and improves the ink repellency of the non-image area and the image area. It has the effect of increasing ink receptivity.

Conventionally known desensitizing agents include alkali metal salts or ammonia salts of dichromic acid, phosphoric acid or its salts, ammonium salts, gum arabic, colloidal substances such as carboxymethylcellulose (CMC), etc. There is an aqueous solution containing .

However, 1. These dampening waters containing desensitizing agents have the disadvantage that they do not uniformly wet the non-image areas of the plate, and as a result, printed matter is sometimes stained, and it is difficult to adjust the amount of dampening water supplied. Requires considerable skill.

In order to improve this drawback, the Dahlgren method has been proposed, in which an aqueous solution containing about 20-25% isopropyl alcohol is used as dampening water. This method allows better wetting of non-print areas and requires less dampening water.
It is easy to adjust the balance between the amount of printing ink and water supplied, and the amount of dampening water emulsified into the printing ink is small.
Furthermore, there are many advantages in terms of workability and accuracy of printed matter, such as improved transferability of printing ink onto the blanket.

However, since this isopropyl alcohol easily evaporates, a special device is required to keep the concentration of isopropyl alcohol in the dampening solution constant, which makes the dampening solution expensive. Furthermore, isopropyl alcohol has a unique unpleasant odor and is also problematic in terms of toxicity, making it unfavorable in terms of the working environment.

Furthermore, even if this dampening water containing isopropyl alcohol is applied to offset printing using a normal water rod, the isopropyl alcohol evaporates on the rollers and the plate surface, so it cannot exhibit its effect.

Furthermore, in recent years, social interest in industrial pollution has increased significantly, and regulations on the discharge of chromium ions in wastewater have become stricter, and the use of organic solvents such as isopropyl alcohol has tended to be regulated from the standpoint of health and safety. For this reason, a desensitizing agent that does not contain these has been desired.

In order to achieve these objectives, attempts have been made to include, for example, surfactants. For example, Tokuko Sho 55-2507
Publication No. 5 has Polyech! / N glycol and -OCo
A composition containing a surfactant containing CHx CHCOO-structure OJa was published in Japanese Patent Publication No. 55-19.
No. 757 discloses a composition containing Rz O+CIt t CHO+TI or R3 (R+, Rz is an alkyl group), and Japanese Patent Publication No. 5B-5797 discloses a composition containing -C formula R-0+R'-0
h, H (R2 aromatic hydrocarbon group having at least one alkyl substituent, R': alkylene group having 1 to 4 carbon atoms n: -(average number of moles added of -R' -0+)) However, when used as a dampening solution, desensitizing agents containing these surfactants have a surface tension of 35 to 35.
In order to obtain 50 dynes/(2), it is necessary to keep the surfactant concentration in the desensitizing agent considerably high. In addition, in actual planographic printing, the ink/water moves violently under the ink roll, printing plate, and dampening water supply roll that rotate at high speed, so water may adhere to the ink film. ,
There are problems such as ink spreading on the surface of water, but the combination of surfactants proposed above is not sufficient to completely eliminate these problems.

Furthermore, dampening solutions containing these surfactants have the disadvantage that they tend to foam during pumping or stirring.

[Problem that the invention seeks to solve]

The object of the present invention is to be free from the toxicity and disadvantages of the conventional desensitizers mentioned above, and when used as a dampening solution, the supply amount can be easily adjusted without the need for specialized skills. An object of the present invention is to provide a desensitizing agent for lithographic printing plates.

[Means for solving problems]

The present invention provides that the desensitizing agent for lithographic printing plates containing a water-soluble surfactant represented by the following general formula (I) or (IF) is non-toxic and does not require specialized skill to adjust the supply amount. This was done based on the knowledge that

In the general formulas (formulas (I) and (II), R5 and R8 are each a hydrogen atom, an alkyl group, an aryl group or an alkenyl group, R2 is an alkyl group or an aryl group, m and p
is an integer of 1 or more, n and q are O or an integer of 1 or more, M is Na
Alkali metals such as 5KSLi, or NH,, NH(CH
3) s, NH (CJs) 3, Nll (CToO)
1) Generally NH such as s, Ntl (CzH40H) 3, etc.
It is a group represented by R'R'R'(R',R' and R' represent a hydrogen atom or a hydrocarbon which may have a substituent).

The alkyl group represented by R1 and R1 includes an unsubstituted alkyl group and a substituted alkyl group, and the unsubstituted alkyl group is preferably an alkyl group of 01 to C11. Substituted alkyl groups include those having a substituent such as a hydroxyl group, a CI to C3 alkoxyl group, or a halogen atom on the C1 to C11 alkyl group shown above.

Oryl groups include unsubstituted and substituted aryl groups, including phenyl groups, naphthyl groups, and those having substituents such as hydroxyl groups, alkoxyl groups, halogen atoms, and C3 to C1 alkyl groups. included.

Examples of the alkenyl group include a vinyl group, a styryl group, a hydroxystyryl group, and the like.

The alkyl group for R2 is preferably in the range of 08 to CI8, and the aryl group is a phenyl group, a naphthyl group, and those having a substituent thereon such as a hydroxyl group, an alkoxyl group, a halogen atom, a C8 to C, alkyl group, etc. etc.

m and p are preferably integers of 1 to 100, particularly 10 to 100.
An integer of 50 is preferred.

n and q are contained within a range that allows the surfactant of general formula (1) or [II) to maintain water solubility, and n and q
Varies depending on the number of Generally, it is selected within the range of 100 or less.

The content of the surfactant represented by general formula CI) or (II) of the present invention is suitably 0.001 to 5% by weight, more preferably 0.001 to 1.0% by weight. ffi% range. In addition, as criteria for selecting an appropriate amount as a dampening water for printing machines, it is preferable to select a surface tension in the range of 25 to 50 dynes/cm, and it is particularly effective to select a viscosity in the range of 1 to 3 cps, which does not easily foam. It is true.

The surfactants of these compounds may be used alone or in combination of two or more (and may also be used in combination with the following surfactants. For example, as anionic surfactants, fatty acid salts, alkylbenzenes, Sulfonates, linear alkylbenzene sulfonates, alkyl sulfates, α
-Olefin sulfonates, alkyl phosphate ester salts, dialkyl sulfosuccinate ester salts, polyoxyethylene alkyl ether sulfates, polyoxydialkyl ether phosphates, N-lauroyl sarcosine salts, naphthalene formalin condensates, alkylnaphthalene sulfonic acids There are salts, diphenyl ether disulfonates, etc.

Nonionic surfactants include polyoxyethylene alkyl ethers, polyoxyethylene alkylphenol ethers, polyoxyethylene polyoxybrobylene block polymers, polyoxyethyl I/insorbitan fatty acid esters, polyoxyethylene glycerin fatty acid esters, polyethylene Examples include glycol fatty acid esters, polyoxyethylene fatty acid amines, fatty acid monoglycerides, sorbitan fatty acid esters, pentaerythritol fatty acid esters, sucrose fatty acid esters, and amine oxides. The nonionic surfactant preferably has an HL B of 8 or more.

A water-soluble polymer compound may be further added to the desensitizing agent of the present invention. Specific examples of such water-soluble polymer compounds include arabic dextrin, alginate 2,
Fiber conductors (e.g., carboxymethylcellulose, carboxyethylcellulose, hydroxyethylcellulose, methylcellulose, etc.) and their modified products; polyvinyl alcohol and its derivatives; polyvinylpyrrolidone; polyacrylamide and its copolymers; Acrylic acid and its copolymers, vinyl methyl ether/
Synthetic products such as maleic anhydride copolymer and vinyl acetate/maleic anhydride copolymer may be mentioned.

These polymer compounds may be used alone or in combination.1. It can be used as a desensitizing agent, and its concentration range is o, oo
oi~25 heavy fence%, more preferably 0°003~=15
Weight % is appropriate.

It is generally preferable to use the desensitizing agent in the acidic region around 113 to 6. If the desensitizing agent is less than 6pl+3, the etching effect on the support will be strong (and the rigidity will decrease. For adjustment, it is sufficient to add a mineral acid, an organic acid, or an inorganic salt.The appropriate amount of addition is 0.005 to 20% by weight.The mineral acids mentioned above include nitric acid, sulfuric acid, and phosphoric acid. etc., and organic acids and 1~ citric acid, acetic acid, oxalic acid, malon fi, p-toluenesulfone M
,? Examples include i1-taric acid, malic acid, lactic acid, levulinic acid, and organic phosphonic acid. These mineral acids, organic acids or inorganic salts may be used alone or in combination of two or more.

If necessary, in addition to the above-mentioned components, a wetting agent may be added to suppress dryness and improve suitability for use.

Suitable wetting agents include glycerin, ethylene glycol, butylene glycol, butylene glycol, bentanediol, hexylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, sorbitol, pentaerythritol. The appropriate amount of the wetting agent used is 0.05% by weight or less.

In addition to the above components, a chelate compound can also be added to the desensitizing agent of the present invention. Desensitizing agents usually have a concentrated composition, which is diluted by adding tap water, well water, etc., and mixed with dampening water. and use it. At this time, calcium L ions and the like contained in the tap water or well water to be diluted may have an adverse effect on printing and may cause printed matter to become easily stained. In such a case, the above-mentioned drawbacks can be overcome by adding a KiI/-) compound to the desensitizing agent. For example, preferable Kir-1 compounds include:
Ethylenediaminetetoacetic acid, its potassium salt, its [-lium salt; diethinone I-lyaminebentaacetic acid,
Its potassium salt, its sodium salt; triethyl/tetramine hexaacetic acid, its potassium salt, its thorium salt; hydroxyethylethylenediaminetriacetic acid, its potassium salt, its sodium salt; nitrilotriacetic acid, its potassium salt, its sodium salt; Aminopolycarboxylic acids such as 1,2-diaminocyclohexanetetoacetic acid, its potassium salt, and its sodium salt; -Phosbobutanetricarboxylic acid M-1,2,4, its potassium salt, its sodium salt; 2-phosphonobutanetricarboxylic acid-2,3,4, its potassium salt, its sodium salt; 1-phosphonoethanetricarboxylic acid -1,2,2, its potassium salt, its sodium salt; 1-hydroxyethane-1,1-diphosphonic acid, its potassium salt, its sodium salt; aminotri(methylenephosphonic acid), its potassium salt, its sodium salt, etc. Examples include organic phosphonic acids and phosphotricarboxylic acids such as. Salts of organic amines are also effective in place of the sodium salts or potassium salts of the above-mentioned chelating agents. These chelating agents were selected because they stably exist in dampening water and do not impede printability. The amount added to the dampening ice water solution is 0.01~
3% by weight, preferably 0.02-1% by weight is suitable.

Furthermore, coloring agents, preservatives, etc. can be added to the desensitizing agent of the present invention. For example, benzoic acid and its derivatives,
Phenol, formalin, sodium dehydroacetate, etc. may be added in the range of o, o o s to 5% by weight.

The desensitizing agent of the present invention can be used for various lithographic printing plates, but in particular, a photosensitive lithographic printing plate having an aluminum plate as a support and a photosensitive layer thereon (previously imparted with photosensitivity) It can be suitably used for a lithographic printing plate obtained by imagewise exposure and development of a lithographic printing plate (called a PS plate).

Preferred such PS versions are, for example, British Patent No.
, 350.521, in which a photosensitive layer made of a mixture of a 4-azo resin (salt of a condensate of p-diazodiphenylamine and paraformaldehyde) and shellac is provided on an aluminum plate, British Patent No. 1,
A photosensitive material comprising a mixture of a diazo resin and a polymer having hydroxyethyl methacrylate units or hydroxyethyl acrylate units as a main repeating unit as described in the specifications of No. 460,978 and No. 1.505.739. Negative type 28 plate, such as one in which the layer is provided on an aluminum plate, and JP-A-50-1258
This includes a positive type 28 plate in which a photosensitive layer made of a mixture of a 〇-quinone diazide photosensitive material and a novolac type phenol resin is provided on an aluminum plate as described in Japanese Patent No. 06. Further, there is 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, and U.S. Pat. No. 4,072,528. No. 4.072.527
PS plate in which a photosensitive layer of a photopolymerizable photopolymer composition as described in each specification of the British Patent No. 1,235.281 and British Patent No. 1,49 is provided on an aluminum plate.
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 the specifications of No. 5,861.

Next, an example of use when using the PS version will be described.

First, the PS plate is imaged exposed and then developed to create a lithographic printing plate. After washing the lithographic printing plate with water and squeezing out the water on the plate surface, pour an appropriate amount of the plate surface protectant onto the plate surface and rub it with a sponge so as to coat the entire surface of the plate. This results in
Non-image areas on the plate are protected and the lithographic printing plate can be stored.

To start printing, the gum on the printing plate is washed off with water, and then printing is carried out according to the normal procedure.

The desensitizing agent of the present invention can be used as a desensitizing agent for lithographic printing plates and as a dampening solution. When used as a dampening solution, it is generally diluted with water, and there is no background stain or oxidation stain, and printing is possible with a small amount of use, resulting in good prints, improving printing efficiency, It is possible to measure productivity improvement. It can also be used in conjunction with Dahlgren's alcohol dampening solution without any problems.

〔Example〕

Next, the present invention will be specifically explained using examples.

Note that % indicates weight % unless otherwise specified.

Example-1 Pure water 800
Parts by weight Phosphoric acid (85%) 20 Dibasic ammonium phosphate 40 Sodium nitrate 20 Gum arabic (14°
B6) Aqueous solution 80〃n, m=40 R+, Ry =C5ll+t n-propyl alcohol 15〃After making an aqueous solution with the above composition, formalin (37%
) 3 parts by weight was added to prepare a desensitizing agent. This desensitizing agent stock solution was diluted 100 times to make dampening water, and the solution was set in a Heidelberg KOR-D printing machine. On the other hand, as a printing plate, an offset printing plate was prepared by exposing and developing FPS-A (manufactured by Fuji Photo Film ■, photosensitive lithographic printing plate).

This printing plate was divided into two groups, one group was coated with regular gum,
It was puff dry. This is called plate A.

The other was placed in a dryer at 150°C for 3 hours before applying the gum.
Air oxidation was performed after holding for a certain period of time. Next, the entire plate surface was wiped with a sponge impregnated with the desensitizing agent stock solution, and after being left for 30 seconds, it was wiped off with water. This is called plate B.

Plates A and B thus obtained were each mounted on a Heidelberg KOR-D type printing machine and evaluated for the following items.

a. Desensitizing power when printing 8500-1000 sheets,
Compare the surface air oxidation stains on Plate B LJ with Plate 1-A.

There is no difference.　　　　　　　　　　　○There is a slight difference.

The Δ difference is obvious.
× Also, regarding the following items, ordinary plate A was attached to a printing machine and the characteristics of the dampening solution were evaluated.

b. Water stick stain: Examine the degree of ink adhesion to the water rod Mol I roll.

Good/ ○ Slightly inferior.
△Inferior.
×C, Brie F property: Using ink (Dainippon Ink Super HG Beni S), 5000 sheets and 1
After printing 0,000 sheets, stop the operation of the printing press and check the extent to which the ink in the printed area bleeds into the non-printed area.

There is almost no bleeding, and there is some bleeding. ΔThere is a lot of bleeding.
×d, Emulsifying property: When too many sheets are printed,
Check the ink emulsification state on the ink mixing roll.

good. ○Slightly bad,
△Bad.
, e. Continuous stability: Using fresh water as dampening water, print 10,000 sheets, determine the dampening water seal (minimum amount of watering) that does not cause stains, and apply each type of dampening water to this minimum amount of watering. The judgment is made based on the number of prints until stains appear on the prints.

10,000 sheets or more 010,000~3
000 sheets Δ Less than 3000 sheets Plate B gave excellent prints comparable to plate A, and no staining occurred even after printing 50,000 sheets. Therefore, it can be seen that the desensitizing agent of the present invention has an excellent desensitizing effect.

In addition, as a result of testing the dampening water permeability of the plate surface using Play) A, it was found that all of the following were excellent: Good prints were obtained. Therefore, it can be seen that the dampening solution obtained by diluting the desensitizing agent of the present invention with water has excellent dampening solution properties.

Examples 2 to 5 Desensitizing agents and dampening solutions having the following compositions were prepared in the same manner as in Example @1, and their desensitizing effects and dampening solution properties were evaluated.

Example-2 Pure water 892 parts by weight Carboxymethyl cellulose 20 (trade name Celogen 6A manufactured by Daiichi Kogyo Yakuhin ■) Magnesium nitrate
30〃Sodium hexametaphosphate
30 Citric acid 20
〃RO-(CHzCHtOh-COCHSOJa (
40χ) 5 ROCOCR2 n=30 R=C+zHzs Phenol 3N Example-3 Pure water 923.5 parts by weight Acrylic acid/methacrylic acid 1o Sodium salt of copolymer (70/30 molar ratio) Magnesium nitrate 3o Phosphorus Acid (8
5%) 1o〃 Second ammonium citrate 20〃mS
n=l~5 p=20~30 RMCH,CH,0h-COC)ISOJ (40X
) 5''RO(CHtCHzOh-COCHg n, m=60 asb is an integer of θ to 4, and a+b is selected from the range of 1 to 4.

4-Isothiazoline 3-one compound 1 Example-4 Pure water 906 parts by weight Nickel nitrate 2o Sodium hexametaphosphate 4o Sodium gluconate 10 Phosphoric acid (85%) 15 a+c=59 b=3-6 R engineering C9H19 Ethyl benzoate phenol 3 Example-5 Pure water 866 weight Magnesium nitrate 20 Magnesium sulfate 10 1-Hydroxy-ethane-1,110-diphosphonic acid (Product name: DEQUEST-2000 manufactured by Monsando Chemical Co., Ltd. ) Sodium malate 40〃n, m=6
0 R=Csfl+t Formalin (37%) 2 Gum Arabic (14°B6) 50 Comparative Example The results obtained are shown in Table 1.

[Efficacy of invention]

The desensitizing agent of the present invention is non-toxic, has no risk of environmental pollution, and exhibits excellent desensitizing effects. The amount of water-soluble surface-active organometallic compound used in this desensitizer is:
It costs about 1/10 of the amount of conventional surfactants and active agents. When this desensitizing agent is diluted with water and used as a dampening solution, a dampening solution having a surface tension of 35 to 50 dynes/effi can be easily obtained. This dampening solution has excellent dryness, brie-F properties, emulsifying properties, and continuous stability, and hardly foams during pumping or stirring.

Procedural amendment 62.1. -6 Showa year, month, day 1, case description 1985 patent application No. 282338
No. 2, Title of the invention: Desensitizing agent for lithographic printing plates 3
, Relationship to the case of the person making the amendment Applicant name (520) Fuji Photo Film Co., Ltd. 4,
Agent specification page 15, lines 12-14 “0.01-3% by weight,
Preferably 0.02 to 1% by weight is appropriate.
0001 to 1% by weight, preferably 0.0002 to 9.5
1% weight is appropriate.''

Claims (1)

[Scope of Claims] A desensitizing agent for lithographic printing plates, characterized by containing a water-soluble surfactant represented by the following general formula [I] or [II]. General formula: [I]▲There are mathematical formulas, chemical formulas, tables, etc.▼ [II]▲There are mathematical formulas, chemical formulas, tables, etc.▼ (In formulas [I] and [II], R_1 and R_3 are hydrogen atoms, alkyl groups, is an aryl group or an alkenyl group, R_2 is an alkyl group or an aryl group,
m and p are integers of 1 or more, n and q are 0 or integers of 1 or more, M is an alkali metal or NHR^4R
^5R^6 (R^4, R^5, R^6 represent a hydrogen atom or a hydrocarbon group which may have a substituent.). )