JPS58105231A - Agent for correcting printing plate - Google Patents

Abstract

PURPOSE:To turn a corrcted part perfectly hydrophilic in a short time, and to obtain a printing print superior in printing resistance in a nonodorous condition, by using a correcting agent contg. a specified s-triazine compd. for correction of a printing plate having a silver image receiving a printing ink. CONSTITUTION:A triazine compd. represented by the shown formula in which R1, R2 are mercapto or hydroxy is dissolved in an org. solvent, water, or a mixture of them by 0.1-20wt% to prepare a nonodorous correcting soln. Said compd. is nonvolatile and stable, and the corrected part of the silver image part of an offset plate having the silver image receiving a printing ink is turned hydrophilic by wiping it with absorbent cotton soaked with said correcting soln. to obtain a corrected plate immediately usable, and besides, the corrected part is superior in printing resistance, and ink stains do not occur even over 5,000 times of printing.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is made by converting the unnecessary portions of the silver image formed on the offset printing plate into hydrophilic ones in the offset printing order of the chain is* from the ink station 11K to 11M. , relates to an image modifying agent for offset printing plates that eliminates ink receptivity, and more specifically, it is used to remove unwanted portions of silver images on offset printing plates formed by photographic or physical methods during the printing process. As appropriate at any stage,
It is concerned with completely making the surface hydrophilic and eliminating ink receptivity without causing any problems to printing properties, substrates, etc., by treating the surface with a specific treatment agent.

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

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

In general, areas that require correction that occur in printing master plates manufactured by photolithography include those that already exist in the original copy, those that occur during exposure, and those that occur due to other uneven development processes. There is.

This means, for example, when using originals in which unwanted images were present in the reproduced original, dust and dirt particles, fingerprints or other stains were present, or originals made by gluing together various 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 make 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 by utilizing the silver image as ink receptive.

For example, hydrophilic metal salts, rubber, latex,
Methods such as precipitation of gelatin or other hydrophilic polymers or pigments, or mechanical removal of the silver image using an eraser, knife, etc., or oxidizing agents and sulphites such as dichromate, red blood salt, etc. For example, the metallic silver in the image area is removed by treatment with a so-called silver image bleach-fixing composition solution containing , thiosulfate, and thiosulfate. However, with the above methods, it is difficult to completely correct the image, the lipophilic image may be exposed again during printing, dirt may cause other problems, and the processing time may be too long, reducing work efficiency. The correction fluid itself is not stable enough and its performance deteriorates during storage. After the film has been formed, erasing the image, that is, correcting it, is practically difficult.

A modifier consisting of a compound having a mercapto or thione group and a hydrophilic group (for example, a hydroxyl group, a carboxyl group, a sulfonic acid group, etc.) in the same molecule, as described in JP-A-48-92101; Improved JP-A-5
Both of the correction agents disclosed in No. 1-21901 and No. 54-53002 are excellent products that have considerably solved the drawbacks of the prior art described above, and are capable of reliably and almost instantaneously correcting silver images. It was possible to make it hydrophilic.

However, despite their excellent modifying ability, these modifiers still have drawbacks. The reason for this is that mercapto compounds have a characteristic bad odor and are easily oxidized like reeds and cysteine, making them unstable when used as a correction solution.Furthermore, since they are made into a strongly acidic solution, they may not have any negative effects on the human body. , ease of handling and workability, etc.

Therefore, there is a strong demand for the development of an odorless correction agent that satisfies the conditions required for a correction agent as described above.

Therefore, it is an object of the present invention to avoid the above-mentioned disadvantages and to
Quick and complete image correction is possible, the correction area will not be exposed again even when printing a large number of sheets, and the correction ability will not deteriorate even during long-term storage.Uses odorless and harmless correction agents. It is to provide.

It has been found that the above objects of the invention are achieved by using S-) lyazine compounds having at least one mercapto group as modifiers.

One specific example of S-) riazine having a mercapto group is 3
It is trithiocyanuric acid with two mercapto groups. The fact that trithiocyanuric acid is effective as a correcting agent for offset printing plates that make silver images ink receptive is based on the fact that trithiocyanuric acid is effective as a correcting agent for offset printing plates that make silver images ink receptive. , It's unpredictable, but 1. S-triazine compounds in which one or two of the mercapto groups of trithiocyanuric acid are substituted with hydrophilic groups include trithiocyanuric acid and the above-mentioned JP-A-48-1999-1.
It has also been found that it has various advantages over the compounds described in No. 92101 and the like.

The S-triazine compound having a mercapto group used in the present invention can be represented by the following general formula.

(In the formula, R1 and R2 each represent a mercapto group or a hydroxyl group.) Compounds in which R1 and FL2 are both mercapto groups, and compounds in which at least one of R□ and R2 is a hydroxyl group are included.

Examples of these compounds are trithiocyanuric acid, ditheocyanuric acid, monothiocyanuric acid.

These compounds are well known, and their synthesis methods and physical properties are described in the book The Chemistry Opheterocyclic Compounds Series published by Interscience Publishers, written by B, M, Smolin Tori, and Labo Boat S-).
Reasins and Derivatives page 105-1
Details are on page 11.

The correction agent of the present invention can be used as a correction fluid using an organic solvent, water, or a mixed solvent thereof. A concentration range of the correcting agent from 0.1 to 20% by weight is sufficient, preferably from 1.0 to 10% by weight.

Also, carboxymethyl cellulose, an element for polyvinyl,
In addition, dyes, organic or inorganic pigments, etc. can be included as elements for coloring the liquid, but these are not essential elements.

Furthermore, fine particle powder as described in JP-A-51-21901 may also be included.

The modifier of the present invention is non-volatile, 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.

Offset printing plates using the toned image of the present invention as ink receptivity include Japanese Patent Publication No. 48-30562, Japanese Patent Publication No. 53-21602, U.S. Patent No. 3.721.559, and U.S. Pat. In addition to U.S. Patent No. 3,
454,398, JP-A No. 53-9603, etc.
Included are offset printing plates that are ink receptive to silver halide images.

Examples will be described below.

Example 1 After subbing a polyethylene terephthalate film (100μ) base with a known aqueous solution containing gelatin, nitrocellulose and Hino(laflorphenol) as main components, a top coating solution prepared with the following composition was applied thereon. After drying, an offset printing plate was obtained.

0.29c nitric acid 1[water WI solution 10'' IX potassium bromide aqueous solution 1ω2X formalin solution 10CCo, oal constant sodium hydroxide aqueous solution Bring the total volume to 2000H with 1000C water.

This was previously subjected to contact treatment with an alkaline reducing agent solution (transfer developer) together with the negative image on the photosensitive negative sheet using the principle of silver complex diffusion transfer using a known method to obtain a positive image on an offset printing plate.

Then, as a correction agent, a correction solution was prepared using the compounds and amounts shown in Table 1 below, each with 80 mmol of caustic soda and water to make a total volume of 100 ml, and the correction solution for the above-mentioned offset printing layer was adjusted. Wipe off the sensitivity layer with scissors correction fluid soaked with 111JIK.

1111 chemical compound shows the number h ditheocyanur concentration in the present invention O correcting agent, the ratio @a shows the thiodyl alcohol concentration, and the comparison shows the theoligoic acid.

After the off-cut mark S* arrives at the printing machine ICIII, the next o
m-formation o-ttavats lipophilization 1m) t, nine and d
Remove m5eca by rubbing and wiping.
1m<give.

3-mercapto-◆-attrikai-5-1-hebutyl-
1, 4-triazole LIP isopbano, Ru
l! IOsg water
250 - Immediately after that, printing was started and the ink stain on the corrected area was observed. Comparison a was 2. OO0 pieces,
In comparison, stains occurred after printing 3,000 sheets, but with Compound A of the present invention, no stains occurred at all even after printing 5,000 sheets or more. Further, correction liquid part 2 and Na3 had a mercapto odor, but the correction liquid mt of the present invention had no odor at all.

Example 2 Hydroquinone 1. A lithographic printing material was prepared in the same manner except that Ofed was contained.

After the imagewise exposure of the lithographic printing material, transfer development is carried out by immersion 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 (25°C). After soaking and squeezing to remove excess liquid, the material was dried under atmospheric conditions.

(Stop It) Water! The printing order obtained in this way is
Otsuset printing machine knee Φbi, -O dick $80. CD
(Mu・B・D%・kl!l0CD product name),
In the direction @Fukiro, I did the Otori - Kaiwi % A nine-post stamp. Printing room gss°C, once 110X'e 9.

(IA) Water 400111 Taenoic Acid.

Taenjun natrichum Lit-mercapto-5-hebuty #-1,8,1 oquinacyazole
O,If Etereno Gricool
When I stopped the printing machine and restarted printing, I was able to obtain over 1,000 sheets of high-quality printed matter with no ink stains.

Similar results were obtained by using the F-O modified f/IL at the start of printing.

Example 3 Example 1 was repeated except using monothiocyanuric acid or trithiocyanuric acid as the modifier. Similar results were obtained.

Example 4 Example 2 was repeated except using monothiocyanuric acid or trithiocyanuric acid as the modifier. Similar results were obtained.

Claims (1)

[Claims] (1) Chain-IIt- In the printing ink receptivity used as an ink layer modifier Km, it is specified that the armpit modifier contains an 8-triazine compound represented by the following general formula.
Marked as l - wear corrector. General formula (wherein and a each represent a hydroxyl group before a mercapto group)