JPH0635217B2 - Processing liquid for lithographic printing - Google Patents

Description

The present invention relates to an electrophotographic offset master, a processing liquid used for printing a PS plate, that is, an etching liquid and a fountain solution.

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

Further, there are a method of forming an image directly on the master by using an oleophilic writing instrument or type to form a printing plate, and a method of using an electrophotographic transfer method.

These are subjected to etching treatment to convert the non-image area from lipophilic to hydrophilic to form a printing plate. In order to maintain hydrophilicity during printing, the treatment liquid is usually diluted several times and used as fountain solution.

Many treatment solutions have been proposed so far. When they are classified by main component, they are divided into yellow blood salt system and non-yellow blood salt system.
The yellow blood salt system has been used for a long time. This is unstable with respect to heat and light, and has drawbacks such as a decrease in etching force and the occurrence of precipitation even after natural aging. Therefore, many proposals have been attempted to improve these drawbacks. Further, with respect to the non-yellow blood salt system, efforts are continuing mainly for improving the etching power. However, they are still not enough. Further, in recent years, the range of application of printing by the electrophotographic offset master has expanded, and higher performance than ever has been required.

That is, printing stains do not occur on the non-image area and ink is sufficiently applied on the image area (= good inking property), and to prevent stains such as fingerprints, it is made hydrophilic with a planographic printing treatment liquid immediately after plate making. Even after printing for several hours after the treatment, the highlights of fine lines and halftone dots do not fade and ink is sufficiently applied (= good ink receptivity after being left to dry), and normal printed matter immediately after printing. Is obtained (= ink is applied quickly), and background stain does not occur even when printing a large number of sheets.
Even if ink is mistakenly attached to the non-image area and it becomes dirty, it can be easily removed by spinning the printer (excellent in removing ink adhesion dirt), and it has hydrophilicity even after long-term use. However, it must have the characteristics that it does not generate crystals and debris.

(Problems to be solved by the invention) However, when the conventional treatment liquid is put into an etching machine that mechanically etches and used, crystals are precipitated in the squeeze roller portion or in the vicinity of the water line, There is a problem in that it adheres to the printing plate and becomes dirty, and if crystals are deposited on the ball bearings or the like, mechanical failure occurs.

As a method of preventing this, there is a method of reducing the content of the main agent. In this case, although crystal precipitation can be prevented, stains are generated in the non-image area at the time of printing, which causes background stains on the printed matter.

On the other hand, when etching treatment is performed using a conventional treatment liquid and drying is performed, there is a drawback that the ink receptivity to the image area is deteriorated. This drawback becomes more remarkable when left to stand for a long time (plate setting) after etching and drying.

As a method of preventing this, there is a method of weakening the etching power (dilution, reduction of the content of the main agent, etc.), but in this case as well, deterioration of inking can be prevented as in the above case, but stains on the non-image area at the time of printing, It causes dirt on the ground.

Another method is to add a surfactant. In this case, although it is possible to prevent the inking deterioration without causing scumming on the printed matter, it becomes very easy to cause bubbles, and when used in an etching processor or the like, liquid leakage due to foaming occurs, and the manufacturing suitability is low. There are problems such as getting worse. There is a method of adding an antifoaming agent to eliminate bubbles, but when added until the appearance of the defoaming effect, liquid stability is deteriorated such as phase separation, and side effects such as printing stains are shown. Not practical.

The present invention solves the above-mentioned drawbacks and provides a processing solution for lithographic printing that does not cause scumming of printed matter.

A first object of the present invention is to provide a treatment liquid which does not cause crystals to precipitate in an etching machine or the like, is maintenance-free, and has the same hydrophilicity for a long period of time.

A second object of the present invention is to provide a treatment liquid which has good ink receptivity and does not easily cause print stains under any conditions.

A third object of the present invention is to provide a treatment liquid which is capable of quickly applying ink and is excellent in removing stains adhering to ink.

(Means for Solving Problems) An object of the present invention is to provide at least one copolymer containing at least one repeating unit represented by the following general formulas (I) and (II), and at least one copolymer. The following general formula (II
It has been found that this can be achieved by a lithographic printing treatment liquid containing a compound represented by I) and a yellow blood salt.

General formula (I) General formula (II) In formulas (I) and (II), R ₁ and R ₂ each represent a hydrogen atom or a methyl group, 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 represent Each represents a hydrogen atom or an inorganic base.

General formula (III)In formula III, R_Four~ R₇Are each independently hydrogen atom or carbon
Substituted or unsubstituted alkyl or alkene having a prime number of 1 to 7
Represents a nyl, aryl or aralkyl group, or
R_Four~ R₇Two of them together optionally contain heteroatoms
It forms an optional ring. However, R_Four~ R₇Out of
Not all represent hydrogen atoms at the same time. Furthermore R_Four~
R₇When the is substituted, the substituent is amino
Group, ammonio group, hydroxyl group, acyloxy group
And an acylamino group. A Is a hydroxyl group or
A monovalent acid residue is shown.

The copolymer containing at least one repeating unit represented by the general formulas (I) and (II) will be described in detail.

When R ₃ represents an alkyl group, it preferably has 6 or less carbon atoms such as methyl, ethyl and propyl, and when it represents an aryl group, preferably it has 8 or less carbon atoms such as phenyl and tolyl, and aralkyl. When representing a group, those having 8 or less carbon atoms such as benzyl are preferred.

When R ₃ , M ₁ and / or M ₂ represents an inorganic base,
Examples of inorganic bases include alkali metals and ammonium.

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

The weight ratio of the repeating unit represented by the general formula (I) to the repeating unit represented by the general formula (II) in this copolymer is preferably 9: 1 to 5: 5.

Further, other than the components represented by the general formulas (I) and (II) may be copolymerized as a repeating unit, but they are hydroxyethyl methacrylate, acrylamide, N
-Introduced by producing a copolymer by further using a water-soluble monomer such as acryloylmorpholine, hydroxyethyl acrylamide, styrene sulfonic acid or the like or copolymerized as vinyl acetate and then hydrolyzed,
It is preferably introduced as a hydrophilic group.

Further, the sum of the components represented by the general formulas (I) and (II) in the copolymer is preferably not less than 60% by weight.

The molecular weight of these copolymers is preferably in the range of about 1,000 to 10,000, particularly preferably in the range of about 2,000 to 8,000.

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

Compound Example-1 Compound Example-2 Compound Example-3 Compound Example-4 Compound Example-5 Compound Example-6 Compound Example-7 The amount of these used is 0.01 to 10% by weight, more preferably 0.
It is 1 to 5% by weight.

The above copolymers may be used alone or in combination of two or more, and the amount thereof used is 0.01 to 10% by weight, more preferably 0.1 to 5% by weight.

The compound represented by formula (III) is described in detail below.

In formula (III), R _{4 to} R ₇ are each independently a hydrogen atom or a substituted or unsubstituted alkyl group having 1 to 7 carbon atoms,
It represents an alkenyl, aryl or aralkyl group. It preferably has 1 to 4 carbon atoms. These substituents are selected from an amino group, an ammonio group, a hydroxyl group, an acyloxy group and an acylamino group.

The total number of carbon atoms of R _{4 to} R ₇ is 16 or less, particularly 4 to 1
2 is preferred. Furthermore, not all of R _{4 to} R ₇ simultaneously represent hydrogen atoms. Further, two of R _{4 to} R ₇ may combine to form a ring. The ring may optionally contain heteroatoms such as nitrogen, oxygen and / or sulfur atoms.

A Is a hydroxyl group or a monovalent acid residue, preferably Cl , Br
, I , HSO_Four , HPO_Four Inorganic acid or CH₃-S
O₃ ,HOCOCOO Represents an acid residue of an organic acid such as.

Typical examples of the compound represented by the general formula (III) are shown below, but the invention is not restricted or limited by these.

Compound Example-8 (CH₃)_Four N ・ OH  Compound Example-9 (CH₃)_Four N ・ Cl  Compound Example-10 (CH₃)_Four N ・ HSO_Four  Compound Example-11Compound Example-12 (C₂H_Five)_Four N ・ OH  Compound Example-13 (C₂H_Five)_Four N ・ Cl  Compound Example-14Compound Example-15Compound Example-16Compound Example-17Compound Example-18Compound Example-19Compound Example-20Compound Example-21Compound Example-22Compound Example-23 (C₂H_Five)₃ NH / Cl  Compound Example-24 (CH₃)₃ NH / OH  (Aqueous trimethylamine solution) Compound Example-25(Methylamine aqueous solution) Compound Example-26These compounds can be used alone or in a mixture.
However, the amount used (total amount when mixed) is preferable.
0.001 to 5% by weight, more preferably 0.01 to 1% by weight
Is.

Further, the copolymer containing the repeating unit represented by the general formula (I) and (II) and the compound represented by the general formula (III) can be arbitrarily combined, but especially the copolymer of the compound example-1 A combination of the polymer and the compound of Compound Example-9, 12 or 13 can be preferably used.

As the main agent for hydrophilization, yellow blood salt and phosphate can be used, and the red blood salt can be partially contained in the yellow blood salt, which is generated by oxidation of the yellow blood salt.

In addition to this, a pH adjusting agent and a pH buffering agent can be used in combination. They use the well-known inorganic acids, organic acids and salts thereof alone or as a mixture. 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,
Pyruvic acid, glycolic acid, salicylic acid, adipic acid,
Hydroacrylic acid, glyceric acid, p-toluene sulfonic acid and their metal salts, organic amine salts and the like.

It is also preferable to add a chelating agent such as EDTA-2Na and a reducing agent such as sulfite, especially when the main agent for hydrophilicity is yellow blood salt, in order to maintain the hydrophilicity and prevent precipitation.

When the main agent is phytate, it is further disclosed in JP-A-60-23.
It is also desirable to add a water-soluble cationic polymer shown in No. 099 and a low molecular weight electrolyte compound in order to prevent stains from occurring.

Further, as a wetting agent and a wetting agent, ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, glycerin, gum arabic, carboxymethyl cellulose, acrylic polymer, methanol, ethanol, iso- and normal propyl alcohol, triethanolamine and the like can be added.

Further, a preservative such as salicylic acid, phenol, butyl phenol parabenzoate, sodium dehydroacetate, or a 4-isothiazolone-3-one compound can be added.

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

In applying the processing solution for lithographic printing according to the present invention to a printing plate, it may be used in any processing machine of an etching processor conventionally used in this field.

Further, the characteristics can be sufficiently utilized for both hand etching and pre-etching for the purpose of preventing stains such as fingerprints.

The processing solution for lithographic printing can also be diluted with water to be used as fountain solution for the offset master or PS plate.

Examples of the present invention will be shown below. However, this does not restrict the present invention.

Example 1 Potassium ferrocyanide 20 g Ammonium phosphate 60 g Diammonium citrate 10 g Sodium sulfite 6.0 g EDTA-2 sodium 0.4 g Acrylic acid / maleic anhydride copolymer 10 g Sodium salt (weight ratio 80/20) (Molecular weight 5,000- 10,000) Tetraethylammonium chloride 2 g Water (total) 1000 g This formulation was used as an etching solution and further diluted 7 times with water to make fountain solution. The master made by Fujifilm ELP-, Mark II system was used as an ELP ink (ink, It was printed with a Hamada Star 800 using a quick drying method. It was possible to print clearly from the print start to 10,000 sheets without getting dirty. Further, the 3000 plate treatment was tested for one month while replenishing the etching liquid. As a result, the first 1st edition and the last 300
There was almost no difference in the quality of the printed matter of the 0th plate, and no deterioration in hydrophilicity, ink receptivity, etc. was observed. Almost no crystals, debris, or precipitates were found in the etching equipment. In addition, no foam was observed during the treatment. Further, when the master that had been left for 2 days in the room after etching and drying was printed in the same manner (drying and leaving test), the inking of the highlight portions of thin lines and halftone dots was extremely good.

Comparative Example 1 Tests were carried out in the same manner except that the acrylic acid / maleic anhydride copolymer sodium salt and tetraethylammonium chloride were omitted from the formulation of Example 1. 1 of 3000 plate processing while replenishing the etching liquid
In the monthly test, crystals, debris, and precipitation started to be generated in the etching device on the third day after the start, and after that, the crystals further increased and adhered to the printing plate to cause printing stains. Further, after one month, crystals were deposited and deposited on the bearing portion, which hindered the drive of the device. Furthermore, in the dry standing test, it was found that the ink did not easily get on a part of the image.

Comparative Example 2 All tests were carried out in the same manner as in Example 1 except that the same amount of sodium polyacrylate was used instead of the sodium salt of acrylic acid / maleic anhydride copolymer in Example 1 and tetraethylammonium chloride was excluded. Was done.

In the 1-month test of 3000 plate processing while replenishing the etching liquid, crystals, debris, and precipitation started to appear in the etching device from the 7th day after the start, and after that, the number of the crystals further increased and adhered to the printing plate to cause printing stains. Became. Further, after one month, crystals were deposited and deposited on the bearing portion.

Example 2 Instead of the sodium salt of acrylic acid / maleic anhydride copolymer sodium salt in Example 1, an equal amount of acrylic acid / methacrylic acid / maleic anhydride copolymer (weight ratio 70/10 /
20 and a molecular weight of 5,000 to 10,000), and the same test as in Example 1 was carried out except that equimolar tetra-n-propyl hydroxide was used instead of tetraethylammonium chloride. The results were as satisfactory as those of Example 1 and were satisfactory.

Example 3 In place of the acrylic acid / maleic anhydride copolymer sodium salt in Example 1, 8 g of the copolymer shown in the above compound example-4 and in place of tetraethylammonium chloride, the compound shown in the above compound example-25 was used. Aqueous solution (10wt
%) 30 g was used, and the plate was made and printed in the same manner as in Example 1.

Furthermore, while replenishing this etching solution, 300 in 2 weeks
As a result of performing the 0th plate treatment, the same results as in Example 1 were obtained.

Further, as a result of printing the master left for 2 days in the room after etching drying, no change was observed in the inking property.

Example 4 15 g of the copolymer shown in the above compound example-6 in place of the sodium salt of the acrylic acid / maleic anhydride copolymer in example 1 and 3 g of the compound shown in the above compound example-17 in place of the tetraethylammonium chloride. A plate was made and printed in the same manner as in Example 1 except that was used.

Furthermore, while replenishing this etching solution, 300 in 2 weeks
As a result of performing the 0th plate treatment, the same results as in Example 1 were obtained.

Further, as a result of printing the master left in the room for 2 days after etching drying, no change was observed in the inking property.

Example 5 Instead of the sodium salt of the acrylic acid / maleic anhydride copolymer in Example 1, 15 g of the copolymer shown in the above compound example-7 and 2 g of the compound shown in the compound example 18 were used in place of tetraethylammonium chloride. Other than that, the plate was made and printed in the same manner as in Example 1.

Furthermore, while replenishing this etching solution, 300 in 2 weeks
As a result of performing the 0th plate treatment, the same results as in Example 1 were obtained.

Further, as a result of printing the master left in the room for 2 days after etching drying, no change was observed in the inking property.

(Effect of the Invention) The treatment liquid of the present invention has excellent production suitability and excellent performance for preventing the formation of crystals, dust, precipitation, etc. in an etching apparatus, and a printed matter obtained by using the same. Also has excellent properties in terms of ink receptivity and scumming.

The compounds contained in the lithographic printing treatment liquid of the present invention include commercially available products and the like, which can be taken in relatively easily, and the present treatment liquid having excellent performance can be easily and economically prepared.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Sadao Osawa, 4000, Kawajiri, Yoshida-cho, Hara-gun, Shizuoka Prefecture, Fujisha Shin Film Co., Ltd. Incorporated company (72) Inventor Eiji Era 4,000 Kawajiri, Yoshida-cho, Haibara-gun, Shizuoka Prefecture Fuji Shashin Film Co., Ltd. (56) Reference JP-A-58-215399 (JP, A)

Claims (1)

[Claims] 1. A repeating unit represented by the following general formulas (I) and (II):
At least one type including at least one return unit
Of at least one of the following general formula (III)
Compound and a yellow blood salt
Processing liquid for lithographic printing. General formula (I)General formula (II)In formulas (I) and (II), R₁, R₂Are hydrogen atom or methyl
R group₃Is hydrogen atom, alkyl group, aryl
Group, aralkyl group or inorganic base, M₁, M₂Are each
Indicates a hydrogen atom or an inorganic base. General formula (III)In formula (III), R_Four~ R₇Are each independently a hydrogen atom or
C1-7 substituted or unsubstituted alkyl, ar
May or may not represent a kenyl, aryl or aralkyl group
Is R_Four~ R₇Two of them together optionally contain heteroatoms.
Forms a ring that may have. However, R_Four~ R₇Out of
Not all of them represent hydrogen atoms at the same time. Furthermore R_Four
~ R₇Is substituted, the substituent is
Group, ammonio group, hydroxyl group, acyloxy group
And an acylamino group. A Represents a hydroxyl group or a monovalent acid residue.