JPS63139353A - Retouching liquid for printing plate - Google Patents

Abstract

PURPOSE:To permit faster and surer retouching, to maintain long-term retouching capacity and to improve the preservable stability of a retouching liquid by incorporating amino alcohol into the retouching liquid for printing with which a silver image is utilized as an ink receptor. CONSTITUTION:Primary - tertiary amine compd. contg. at least one hydroxyalkyl group expressed by the formula are used. In the formula, X, X' are H, hydroxyl group or amino group, l and m are 0 or >=1 integer, n is >=1 integer. More specifically, said compds. are ethanol amine, etc., which are added to the retouching liquid in a 0.5-2mol range per 1l of the retouching liquid. The amino alcohol prevents the silver image part, which is imparted with a hydrophilic property by the retouching agent, from changing to the ink receptor to maintain said silver image part stably. The retouching liquid is prepd. by dissolving said alcohol together with 0.1-0.5mol per 1l of the ferric salt of aminopolycarboxylic acid and >=0.3mol per 1l of potassium bromide into water. The extremely effective retouching liquid for printing for a retouching pen is thus obtd.

Description

Detailed Description of the Invention (A) Industrial Application Field The present invention is directed to an offset printing plate in which a silver image is made ink receptive and unnecessary portions of the silver image formed on the printing plate are made hydrophilic. The present invention relates to an image modifying agent for offset printing plates that eliminates ink receptivity by converting the ink receptivity to color, and more specifically, it eliminates unnecessary silver images on offset printing plates formed photographically or physically. This process involves treating the surface of a part with a specific treatment agent at any stage in the printing process to completely make it hydrophilic and eliminate ink receptivity without causing any problems to the printing properties or base material. be.

Since such processing is usually called "correction" in the printing field, the present inventors will follow this term hereinafter.

Furthermore, the processing agent used in the correction operation will be referred to as a "correction agent."

(B) Prior art and its problems In general, areas that require correction that occur in printing master plates manufactured by photolithography include those that already exist in the copy original, those that occur during exposure, and other irregularities. - There are some that occur during the development process.

This means, for example, if there are unwanted images in the reproduced original, if there are dust and dirt particles, fingerprints or other stains, or if the original is made by gluing together different originals, Shadows may appear during exposure.

In order to obtain good printed matter, all of these points must be corrected during the plate-making and printing stages.

Generally speaking, correction operations are essential, and it is desirable to be able to perform necessary corrections at any stage of the plate-making and printing processes.

Many attempts have been made to correct unwanted images in offset printing plates that utilize silver images for ink receptivity.

For example, JP-A-48-92101, JP-A-51-21901
Compounds having a mercapto or thione group and a hydrophilic group described in ``Sho 54-53002, ``Sho 59-9661, etc.'' can reliably and almost instantaneously make silver images hydrophilic. It is.

In addition, in JP-A No. 48-41808, blush salt and EDTA
A retardant consisting of a silver oxidizing agent such as a metal salt and a thiocyanate has been described.

In addition, the present inventors have separately proposed a modifying agent consisting of an organic acid ferric salt and a halide (eg, potassium bromide, ammonium bromide, potassium iodide, etc.).

By the way, these corrective agents used in lithographic printing plates that use silver images as ink receptive ones gradually lose their correcting ability over time or during printing after being corrected, and become ink receptive again. It has the disadvantage of causing stains. In particular, this drawback is more noticeable at the edges that have been corrected when the silver image area is lightly rubbed, as in a method commonly called matchstick correction or a correction pen method.

Therefore, it is required that the correction effect be stably maintained for as long as possible after correction.

(C) Object of the Invention The object of the present invention is to provide an offset printing plate that can be quickly and reliably corrected, retains the ability to correct for a long time after correction, and has excellent storage stability of the correction agent solution. It is to provide correction fluid.

Other objects of the invention will be understood from the following description.

(D> Constitution of the Invention The above object of the present invention has been achieved by a correction liquid for offset printing plates that utilizes a silver image as ink receptivity, and is characterized by containing an amino alcohol.

The amino alcohol used in the present invention is a primary, secondary or tertiary amine compound having at least one hydroxyalkyl group. Amino alcohol has the general formula (A
>Includes compounds represented by.

General formula (A) (X and X- represent a hydrogen atom, a hydroxyl group, or an amine group; β and m are O or an integer of 1 or more; n is 1
represents an integer greater than or equal to ) Specifically, ethanolamine, jetanolamine, triethanolamine, diisopropanoamine, N-methylethanolamine, N-
Aminoethylethanolamine, N,N-diethylethanolamine, N,N-dimethylethanolamine, N
-Methylgetanolamine 1, N-ethylgetanolamine, 3-aminopropanol, 1-amino-propan-2-ol, 4-aminobutanol, 5-amino-pentan-1-ol, 3.3-- Examples include iminocybrobanol and N-ethyl-2,2''-iminodiethanol.

Furthermore, 2-amino-2-(hydroxymethyl)propane-1,3-diol, 2-amino-2-methylpropane-1,3-diol, and the like can also be used.

Amino alcohol is correction fluid 1! The amount ranges from about 0.3 to about 3 moles, preferably from about 0.5 to about 2 moles.

The mechanism of action of amino alcohol is not clear, but it prevents the silver image areas made hydrophilic by the correcting agent, especially the silver image areas that have been rubbed off, from gradually changing to ink receptivity, and keeps them stable. considered to be a thing.

The correction fluid of the present invention containing an amino alcohol is particularly useful for use in so-called correction pen systems such as felt-tip pens. That is, it not only improves the stability of the corrected edge over time as described above, but also functions as a drying inhibitor to prevent the corrected pen from overdrying.

The correction fluid of the present invention containing amino alcohol can use various compounds as described above as correction agents.

Particularly preferred is the use of a silver oxidizing agent such as an organic acid ferric salt and a compound that converts silver ions into a silver complex salt or silver halide.

A preferred example of the organic acid ferric complex salt is an aminopolycarboxylic acid ferric salt, but a phosphonic acid ferric salt can also be used.

Organic acid ferric complex salts are usually used in the form of complex salts, but ferric salts such as ferric sulfate, ferric chloride, ferric nitrate, ferric ammonium sulfate, and ferric phosphate A ferric ion complex salt may be formed in a solution using diiron or the like and an organic acid.

The aminopolycarboxylic acid secondary complex salt is a mirror body of a ferric ion and an aminopolycarboxylic acid or a salt thereof.

Representative examples of aminopolycarboxylic acids and their salts include ethylenediaminetetraic acid 1 (EDTA), EDTA disodium salt, EDTA diammonium salt, EDTA tetra(trimethylammonium) salt, EDTA tetrapotassium salt, EDTA tetrasodium salt, EDTA trisodium salt, diethylenetriaminepentaacetic acid, diethylenetriaminepentaacetic acid pentasodium salt, ethylenediamine-N-(β-oxyethyl)-N, N-1N
'-Triacetic acid, ethylenediamine-N-(β-oxyethyl)-N, N=, N'-triacetic acid triammonium salt, propylenediaminetetraacetic acid, propylenediaminetetraacetic acid disodium salt, nitrilotriacetic acid, nitrilotriacetic acid trisodium salt , cyclohexanediaminetetraacetic acid, cyclohexanediaminetetraacetic acid disodium salt, iminodiacetic acid, dihydroxyethylglycine, ethyl etherdiaminetetraacetic acid, ethylenediaminetetrapropionic acid, and the like.

Further, typical examples of phosphonic acids or salts thereof include diethylenetriaminepentamethylenephosphonic acid, cyclohexanediaminetetramethylenephosphonic acid, triethylenetetraminehexamethylenephosphonic acid, glycol ether diaminetetramethylenephosphonic acid, and 1,2-diaminopropane. Tetramethylenephosphonic acid, methyliminodimethylenephosphonic acid, 1,3-diaminopropane-2
-All-tetramethylenephosphonic acid, ethylenediaminetetramethylenephosphonic acid, and the like.

Any combination of these organic acids and the above-mentioned ferric salts can be used.

Organic acid ferric salts are used to oxidize silver images used for ink receptivity, and oxidize silver images to which mercapto compounds, etc., which are generally used to enhance lipophilicity, are strongly adsorbed. It is recommended to use a relatively large amount. In general, the amount is preferably in the range of 0.05 to 1.0 mol, preferably 0.1 to 0.5 mol, per 11 of the modifier solution, and two or more types may be combined.

The compound to be combined with the organic acid ferric salt is preferably a soluble bromide or a soluble iodide.

Soluble bromide, soluble iodide means bromide and iodide that are soluble in the solvent of the corrector solution.

Usually, water is used as part or all of the solvent, so
Specific examples include water-soluble bromides or iodides such as potassium bromide, sodium bromide, ammonium bromide, potassium iodide, sodium iodide, and ammonium iodide.

The amount of soluble bromide or soluble iodide is required to be at least 0.3 mol per 111 of the corrector solution, preferably 0.
．． The amount is up to 5 mol or more and can be dissolved.

Two or more types may be combined.

Other examples of compounds for combination with organic acid ferric salts are silver halide complex formers, such as thiocyanates, thiosulfates, and the like.

The correction fluid of the present invention preferably uses water, various alcohols, or a mixed solvent thereof as a solvent.

It can also contain elements to make the liquid viscous, such as carboxymethylcellulose alcohol and glycerin, and elements to color the liquid, such as pigments, organic or inorganic pigments, but these are not essential elements. do not have.

Furthermore, fine particle powder as described in JP-A-51-2'1901 may also be included.

The modifier of the present invention is stable and odorless. In addition, it can be corrected quickly and completely, and even if it is rubbed strongly after correction, ink will not get on the correction area.

Therefore, a larger number of sheets can be printed.

Examples of offset printing plates using the silver image of the present invention as ink receptivity include Japanese Patent Publication No. 718-30562@, Japanese Patent Application Laid-Open No. 53-21602, and US Patent No. 3.

No. 721,559, No. 3,490,905, etc., as well as U.S. Patent No. 3,454,398, and Japanese Unexamined Patent Publication No. 1986-96.
Also included are offset printing plates that are ink receptive to silver halide images, such as No. 03.

(E) Examples Example 1 1.0 g/m of hydroquinone is contained in the physical image nucleus layer of the offset printing plate (Plate No. 3) described in Example 1 of JP-A-53-21602@Specification. A lithographic printing material was produced in the same manner except that

After the image-wise exposure of the lithographic printing material, transfer development was carried out by immersing it in a transfer developer having the following formulation for 30 seconds at 30°C, followed by immersion in a stop solution having the following formulation for 30 seconds (at 25°C). ) immersion, squeezing to remove excess liquid, and drying the material under atmospheric conditions.

A correction fluid was prepared using the compounds and amounts shown in Table 1 below and filled into felt correction pens. The areas to be corrected on the above planographic printing plate were corrected by rubbing them with these correction pens.

[Transfer developer]

[Stopping liquid] The printing plate thus obtained was processed using an offset printing machine Nie B. Dick 350CD (A.B.Dick350C).
D (trade name) was attached, and printing was performed after wiping the plate surface with a liquid called Prescription (E). The printing room was at 22°C and 60% humidity.

(E) After correction, printing was carried out immediately, 8 hours later, 24 hours later, and 48 hours later, and the results are shown in Table 2.

The revised evaluation of the revised part is as follows.

revised evaluation O: Does not accept ink at all.

Δ... Slight ink receptivity.

X: Perfect ink receptivity.

(Margin below) Table 1 Table 2 Example 2 The amino alcohol in the correction fluid of Example 1 is monoethanolamine, triethanolamine, N, N
Example 1 except that '-diethylethanolamine is used.
repeated. The results were similar.

In addition, since the correction pens containing amino alcohol of Examples 1 and 2 dry the pen tip very slowly, corrections could be made even if the cap was removed for a long time, resulting in improved workability.

(F) Effects of the Invention Since the correction liquid of the present invention contains amino alcohol, the correction effect can be stably maintained even if the time between correction operation and printing is long, and the correction pen method By doing so, work efficiency can also be improved due to the effect of suppressing drying of the pen tip.

Claims (2)

[Claims] (1) A correction liquid for offset printing plates that uses a silver image as ink receptivity, and is characterized by containing an amino alcohol. (2) Correction fluid for printing plates according to claim 1, which is for correction pens.