JPS6399993A - Treating liquid for planography - Google Patents

Abstract

PURPOSE:To obtain a treating liquid free of the possibility of precipitation of crystals in an apparatus and capable of maintaining a capability of imparting hydrophilic nature for a long time, by incorporating at least one copolymer containing at least one each of two kinds of specific repeating units and at least one specific compound. CONSTITUTION:A treating liquid for planography contains at least one copolymer containing at least one each of repeating units of general formulas (I) and (II) and at least one compound of general formula (III). The copolymer can be obtained by, for example, a method in which a copolymer of a monomer corresponding to the component of general formula (I) with maleic anhydride is subjected to hydrolysis or alcoholysis. The weight ratio of the repeating unit of general formula (I) to the repeating unit of general formula (II) in the copolymer thus obtained is preferably in the range of 9:1-5:5. The compound of general formula (III) is preferably used in an amount of 0.001-5 Wt.%. The treating liquid has excellent performance of preventing generation of crystals, scum, precipitation or the like, and a printed matter obtained by use of the treating liquid has excellent performance as to ink build-up properties and ground contamination.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to processing liquids, ie, etching liquids and dampening solutions, used for printing electrophotographic offset masters and PEi plates.

(Prior Art) In an electrophotographic offset master, a lipophilic image is first obtained by an electrophotographic method on a photosensitive layer formed by coating a photoconductive fine powder such as zinc oxide on a support together with an electrically insulating resin.

There are also methods of forming a printing plate by directly forming an image on the master using a lipophilic writing instrument or type, and methods of using an electrophotographic transfer method.

These are used as printing plates by converting the non-image areas from lipophilic to hydrophilic through an etching process. In order to maintain hydrophilicity during printing, the processing liquid is usually diluted several times and used as dampening water.

Many treatment solutions have been proposed so far. If they are classified according to their main components, they can be divided into yellow blood salt type and non-yellow blood salt type.

Yellow blood salts have been used for a long time. It is unstable to heat and light, and has disadvantages such as a decrease in etching power and the formation of precipitates even with natural aging. Therefore, many proposals have been attempted to improve these drawbacks. Efforts are being made mainly to improve the etching power of non-yellow blood salts. However, they are still not enough. Furthermore, in recent years, the scope of application of printing using electrophotographic offset masters has expanded, and more advanced performance than before has been required.

In other words, the non-image area should not have printing stains and the image area should have sufficient ink coverage (=good ink adhesion), and should be made hydrophilic with a lithographic printing treatment liquid immediately after plate making to prevent stains such as fingerprints. Even if you print several hours after processing, the fine lines and highlights of halftone dots will not fade or smear, and the ink will get on well (
= ink receptivity remains after being left to dry), normal prints can be obtained immediately after printing begins (= ink build-up is quick), background smear does not occur even when printing a large number of sheets, and non-image Even if ink accidentally adheres to a surface and causes stains, the stain can be easily removed by running the printing machine idly (excellent ability to remove ink adhesion stains), and the hydrophilicity does not change even after long-term use. It must also have good characteristics, such as not generating crystal scum.

(Problem to be solved by the invention) However, when a conventional processing solution is used in an etching machine that performs mechanical etching, crystals are deposited on a part of the squeeze roller and near the waterline. This has caused the problem that it adheres to the printing plate and becomes a stain, and that if crystals are deposited on ball bearings or the like, it can cause mechanical failure.

One way to prevent this is to reduce the content of the base agent, but in this case, crystal precipitation can be prevented, but stains may be formed in non-image areas during printing, and background stains may occur on printed matter.

On the other hand, when etching is performed using a conventional processing liquid and then dried, there is a drawback that ink adhesion to the image area deteriorates. This drawback becomes more noticeable when the plate is left for a long time (plate placement) after etching and drying.

To prevent this, there is a method of weakening the etching power (dilution, reducing the content of the main agent, etc.), but in this case as well, deterioration due to inking can be prevented as in the case above, but it may cause stains in non-image areas during printing, and This will cause stains on the surface.

Another method is to add a surfactant. In this case, it is possible to prevent the deterioration of the inking without causing background stains on the printed matter, but it is very easy to create bubbles.
When used in etching processors, etc., there are problems such as liquid leakage due to foaming and poor manufacturing suitability. There is a method of adding an antifoaming agent to eliminate foam, but if it is added until the antifoaming effect appears, the liquid stability deteriorates such as phase separation9, and side effects such as printing stains occur. , impractical.

The present invention solves the above-mentioned drawbacks and provides a processing liquid for lithographic printing that does not cause background stains on printed matter.

The first object of the present invention is to provide a treatment solution that does not cause crystal precipitation in equipment such as etching machines, is maintenance-free, and has a long-term hydrophilicity.

A second object of the present invention is to provide a processing liquid that has good ink receptivity under any conditions and is less likely to cause printing stains.

A third object of the present invention is to provide a processing liquid that has rapid ink multiplication and excellent ability to remove ink-attached stains.

(Means for Solving the Problems) An object of the present invention is to combine at least one copolymer containing at least one 9 repeating unit represented by the following general formulas (I) and (II), and at least It has been found that this can be achieved by a lithographic printing processing liquid containing 1. a compound represented by the following general formula (III);

General formula (I) General formula (n) In the formula (I1), R1%R1υco8 represents a hydrogen atom or a methyl group, R,
represents a hydrogen atom, an alkyl group, an aryl group, an aralkyl group, or an inorganic base, and 4 s Mv represents a hydrogen atom or an inorganic base.

General formula (2) In formula (2), R4-R1 each independently represent a hydrogen atom or a substituted or unsubstituted alkyl, alkenyl, aryl, or aralkyl group having 1 to 7 carbon atoms, or R4-R1 Two of them together form a ring which may optionally contain a heterotetraatom. However, R4~R,
All of them do not exhibit hydrogen atoms at the same time.

Mu0 represents a hydroxyl group or a monovalent acid residue.

Copolymers each containing at least one repeating unit represented by the general formula (I) 1jL and (n) will be described in detail.

When R3 represents an alkyl group, it preferably has 6 or less carbon atoms, such as methyl, ethyl, propyl, etc.; when it represents an aryl group, it preferably has 8 or less carbon atoms, such as phenyl, tolyl, etc.; When this is represented, those having 8 or less carbon atoms such as benzyl are preferred.

When R3, Ml and/or M represent an inorganic base, examples of the inorganic base include alkali metals, anthonium and the like.

The copolymer used in the present invention is, for example, a copolymer of a monomer corresponding to the component of general formula (I) (for example, acrylic acid, methacrylic acid, itanoic acid, etc.) and maleic anhydride. It can be obtained by known methods such as decomposition or alcoholysis.

What is the ratio by weight of the repeating units represented by general formula (I) to the repeating units represented by general formula (I) in this copolymer? :1 to 5:5 is preferred.

In addition, components other than those represented by general formulas (I) and (I) may be copolymerized as repeating units, such as hydroxyethyl methacrylate, acrylamide, N-acryloylmorpholine, hydroxyethyl acrylamide, It is preferable to introduce the hydrophilic group by further producing a copolymer using a water-soluble monomer such as styrene sulfonic acid, or by copolymerizing it as vinyl acetate, followed by hydrolysis, and introducing it as a hydrophilic group.

Further, the weight ratio of the components represented by general formulas (I) and (II) in the copolymer preferably does not exceed 60% by weight.

The molecular weight of these copolymers is suitably in the range of about 00 to 1000 and about 2.00 to 1.000. The range from Goo to a000 is 4I
K is preferred.

Examples of copolymers used in the present invention are shown below, but the present invention is not limited thereto.

Compound Example-1 Compound Example-2 (H3 Compound Example-3 Compound Example-4 H3 Coo)In2 COONH4COONH4 Compound Series-5 0H Tomi cooHoooon ooou Compound Compound Compound Example-7 The amount of these O used is α01 to 10 by weight, more preferably is 11-5 weight ratio.

Further, the above copolymers can be used alone or in combination of two or more, and the amount used is 101 to 10% by weight, more preferably α1 to 5% by weight.

The compound represented by the general formula (III) will be explained in detail below.

In the general formula (2), R4 and R1 each independently represent a hydrogen atom or a substituted or unsubstituted alkyl, alkenyl, aryl or aralkyl group having 1 to 7 carbon atoms.

Preferably it has 1 to 4 carbon atoms.

Preferred examples of these substituents include hydrophilic groups such as an amino group, an ammonio group, a hydroxy group, an acyloxy group, and an acylamino group.

Also, the total number of carbon atoms in R1 to R4 is 16 or less, especially 4 to 1.
2 is preferred. Further, all of KR4 to R1 do not simultaneously represent hydrogen atoms. Two of R1 may be bonded to R4 to form a ring.

The ring may optionally contain heteroatoms, such as nitrogen, oxygen and/or sulfur atoms.

mue is a hydroxyl group or a monovalent acid residue, preferably OL",
Br", Xe, HBOp %HPO4e, etc. (D Inorganic) Representative examples of compounds represented by the general formula (III) are shown below, but the present invention is not restricted or limited by these.

Compound IPII-8(aHs)3-OR” Compound IF
IJ-9(OHs)4toOAe compound fMJ-1o
(011,)4N-B2O,e Compound Example-12 (0,m
ig) 4"1i-On" compound fl+J-1s (c
l! Is), 'Bm-ate compound example-14 Φ (an, -), anlam, -on-cnsso3e
Compound example-15 C horse CHI-1+O horse OB, 0il)s-Br' compound 1Fl-16 (OE110]1iIO horse)4toO2e Compound row-17 1s Compound row-20 Compound example-21 Es Compound fP4-22 0E OIi Compound Example-23 (Can5)s N H-OL" (trimethylamine aqueous solution) Compound fMJ-2s an, Tm, -on" (methylamine aqueous solution) These compounds can be used alone or in combination, but The amount used (total amount when mixed) is preferably α001 to 5 weight ratio, preferably 1101 to 1
I am in charge of heavy R.

Further, the copolymer containing the repeating units represented by general formulas (I) and (!l) and the compound represented by general formula (III) can be arbitrarily combined, but in particular, the above-mentioned compound example 10 Polymer and the above compound 99-9.12 or 1
A combination with compound No. 3 can be preferably used.

As the main hydrophilizing agent, all conventionally known compounds such as yellow blood salt, phosphate, phytate, and hexamine cobalt salt can be used. Yellow blood salt may partially contain red blood salt produced by oxidizing yellow blood salt.

Furthermore, in addition to this, a pH adjuster and 1) H buffering agent can be used in combination. They use well-known inorganic acids, organic acids and their salts alone or in combination. For example, formic acid, acetic acid, butyric acid, valeric acid, lactic acid, tartaric acid, propionic acid, oxalic acid, malonic acid, succinic acid, glutaric acid,
Maleic acid, phthalic acid, citraconic acid, itaconic acid, fumaric acid, tricarballylic acid, glycolic acid, propionic acid, thioglycolic acid, malic acid, citric acid, gluconic acid, hiruvic acid, gelcholic acid, salicylic acid, adipic acid, Hydroacrylic acid, glyceric acid,? -) Luenesulfonic acid, metal salts thereof, organic amine salts, etc.

In addition, addition of a chelating agent such as WTA-2Na and a reducing agent such as sulfite is also preferred, particularly when the main hydrophilizing agent is yellow blood salt, in order to maintain the hydrophilic power and prevent precipitation.

In addition, when the main agent is phytate, JP-A-60-25
It is also desirable to add a water-soluble cationic polymer shown in No. 099 and a low molecular weight electrolyte compound to prevent staining.

In addition, ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, glycerin, gum arabic, carboxymethyl cellulose, acrylic polymer, methanol, ethanol, isopropylene normal propyl alcohol, triethanolamine, etc. can be added as wetting agents and wetting agents. .

Furthermore, preservatives such as salicylic acid, phenol, butyl phenol-parabenzoate, sodium dehydroacetate, and 4-isothiazolone-3-one compounds can be added.

In addition, rust preventives such as sodium nitrite and dicyclohexylammonium nitrite can also be added.

When applying the lithographic printing processing liquid of the present invention to printing plates, it may be used in any etching processor conventionally used in this field.

Furthermore, its characteristics can be fully utilized for hand etching and pre-etching for the purpose of preventing stains such as fingerprints.

Furthermore, this lithographic printing processing liquid can also be used as a dampening water for offset masters and PS plates by diluting it with water.

Examples of the present invention are shown below. However, the present invention is not limited by this.

Example 1 7 Potassium erocyanide 20P monoammonium phosphate 60P diammonium citrate 10P sodium sulfite
topIDT Mu-2 Sodium
α4P acrylic acid/maleic anhydride copolymer
10P sodium salt (weight ratio 80720) (molecular weight 翫ooo~1000) Tetraethylammonium chloride 2P water (total) 1000p Use this formulation as an etching solution, dilute it 7 times with water to make a dampening solution, and use Fuji Film E
The master made with the LF-1 Markl system is
It was printed with Hamada Star 800 using LF ink (black, quick drying). I was able to print 10,000 sheets clearly without any smudges from the beginning of the printing process. Further, the processing of 3000 plates was tested for one month while replenishing this etching solution. As a result, there was almost no difference in the quality of the printed matter between the first edition and the final 3000th edition, and no deterioration in hydrophilicity, ink receptivity, etc. was observed. Almost no crystals, scum, or precipitates were observed in the etching apparatus. Also,
No foam was observed during the treatment. Furthermore, when the master, which had been left indoors for two days after etching and drying, was similarly printed (drying test), the inking of the highlighted areas of fine lines and halftone dots was extremely good.

Comparative Example 1 A test was conducted in the same manner as in Example 1 except that the sodium salt of acrylic acid/maleic anhydride copolymer and tetraethylammonium chloride were excluded. In a one-month test of processing 3,000 plates while replenishing the etching solution, crystals, scum, and precipitates began to form inside the etching device from the third mound after starting, and after that, they continued to increase and adhere to the printing plates. The printing became smudged. Moreover, after one month, crystals were deposited on the bearing, which caused trouble in driving the device. Furthermore, in the drying test, it was found that the ink tended to be difficult to get on some parts of the image.

Example 2 In place of the acrylic acid/maleic anhydride copolymer sodium salt in Example 1, an equivalent amount of acrylic acid/methacrylic acid/maleic anhydride copolymer (weight ratio 70/10/
20, molecular weight 500 to 10,000), and in place of tetraethylammonium chloride, equimolar amount of tetran hydroxide was added.
The test was conducted in the same manner as in Example 1 except that -propyl was used. The results were as satisfactory as in Example 1.

Example 3 In place of the acrylic acid/maleic anhydride copolymer (S) + 7um salt in Example 1, the copolymer 8P shown in Compound Example-4 was used, and in place of tetraethylammonium chloride, the copolymer 8P shown in Compound Example-25 was used. Aqueous solution of compound (I0w
Plate making and printing were carried out in the same manner as in Example 1, except that 30 jl (t%) was used.

Furthermore, while replenishing this etching solution, 500
As a result of performing the zero plate processing, the same results as in Example 1 were obtained.

Further, when the master was left indoors for 2 days after etching and drying, no change was observed in the ink receptivity.

Example 4 In place of the acrylic acid/maleic anhydride copolymer sodium salt in Example 1, the copolymer 15P shown in Compound Example-6 was used, and in place of tetraethylammonium chloride, the compound shown in Compound Example-17 was used. Plate making and printing were carried out in the same manner as in Example 1, except that Compound 3P was used. .

Furthermore, while replenishing this etching solution, it became 300 ml in 2 weeks.
As a result of performing the zero plate processing, the same results as in Example 1 were obtained.

Next, after etching and drying, the master was left indoors for two days and no change was observed in the ink receptivity.

Example 5 In place of the acrylic acid/maleic anhydride copolymer sodium salt in Example 1, 155 g of the copolymer shown in Compound Example-7 and in place of tetraethylammonium chloride, compound 2F shown in Compound Example 18 was used. Plate making and printing were carried out in the same manner as in Example 1, except that .

Furthermore, while replenishing this etching solution, it became 300 ml in 2 weeks.
As a result of performing the zero plate processing, the same results as in Example 1 were obtained.

Further, when the master was left indoors for 2 days after etching and drying, no change was observed in the ink receptivity.

(Effects of the Invention) The processing liquid of the present invention has excellent manufacturing suitability and excellent performance in preventing the generation of crystals, scum, precipitation, etc. in an etching device, and furthermore, the processing liquid obtained by using the processing liquid It also has excellent performance in terms of ink receptivity, background smearing, etc.

The compounds contained in the processing liquid for lithographic printing of the present invention include commercially available products, and can be applied relatively easily, and the processing liquid having excellent performance can be prepared easily and economically.

Claims (1)

[Scope of Claims] 1) At least one type of copolymer containing at least one repeating unit each represented by the following general formulas (I) and (II) and at least one type represented by the following general formula (III). 1. A lithographic printing processing liquid characterized by containing a compound comprising: General formula (I) ▲ Contains mathematical formulas, chemical formulas, tables, etc. ▼ General formula (II) ▲ Contains mathematical formulas, chemical formulas, tables, etc. ▼ In formulas (I) and (II), R_1 and R_2 each represent a hydrogen atom or a methyl group. Show, R
_3 represents a hydrogen atom, an alkyl group, an aryl group, an aralkyl group, or an inorganic base, and M_1 and M_2 each represent a hydrogen atom or an inorganic base. General formula (III) ▲There are numerical formulas, chemical formulas, tables, etc.▼ In formula (III), R_4 to R_7 each independently represent a hydrogen atom, or a substituted or unsubstituted alkyl, alkenyl, aryl or alkyl having 1 to 7 carbon atoms. represents an aralkyl group or two of R_4 to R_7 together form a ring which may optionally contain heteroatoms. however,
All of R_4 to R_7 do not represent hydrogen atoms at the same time. ▲There are mathematical formulas, chemical formulas, tables, etc. ▼ indicates a hydroxyl group or a monovalent acid residue. 2) The processing liquid for lithographic printing according to claim 1, characterized in that it contains yellow blood salt as a main ingredient.