JPS6216200B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a developing ink composition for lithographic printing, and particularly to an emulsion type composition.

Lithographic printing is a printing method that skillfully takes advantage of the property that water and oil essentially do not mix. It consists of a receiving area, the former is called a non-image area and the latter is called an image area.

A developing ink composition for lithographic printing plates makes it easy to visually distinguish image areas and non-image areas of a lithographic printing plate, and at the same time attaches a lipophilic substance to the image areas to increase the receptivity of printing ink. It is applied to lithographic printing plates in order to protect the image areas during various subsequent operations such as gumming.

It goes without saying that such a developing ink composition must have the above-mentioned properties, but it also needs to have the following properties.

(1) Even when the developing ink composition is applied to a halftone image formed on a lithographic printing plate, there is so-called coloration (that is, lipophilic substances contained in the developing ink composition are located adjacent to each other). (Development that adheres so as to bridge between halftone dots or to cover minute non-image areas surrounded by image areas.)

(2) The colored image visualized by the developing ink composition faithfully reproduces the image area formed on the lithographic printing plate (for example, if the visualized halftone dots are thicker than the actual halftone dots) There should be no defects.)

(3) The developing ink composition itself has excellent stability over time (that is, the property that the performance immediately after manufacture is maintained even after a long period of time has passed).

(4) When applying the developing ink composition to a lithographic printing plate, it can be done with a simple tool such as a sponge without using special equipment.

Conventionally known developing ink compositions such as Tinctor have satisfied some of the above-mentioned properties, but none have satisfied all of them.

Therefore, an object of the present invention is to provide a developing ink composition that satisfies the above-mentioned properties.

That is, an object of the present invention is to provide a developing ink composition that does not cause staining.

Another object of the present invention is to provide a developer ink composition that provides a visible image that faithfully reproduces the image areas of a lithographic printing plate.

Another object of the present invention is to provide a developing ink composition with excellent stability over time.

Yet another object of the present invention is to provide a developer ink composition that can be applied onto a lithographic printing plate with simple tools.

In order to achieve the above objects, the inventors of the present invention have made the invention as a result of various studies. That is, the present invention comprises an aqueous phase having a pH in the acidic range, and (a) a volatile solvent that is immiscible with water, (b) a lipophilic resin that can be dissolved in the volatile solvent, (c) a colorant, and
(d) A developing ink composition for lithographic printing plates, characterized in that it is an emulsion consisting of an oil phase containing a surfactant having an HLB value of 1 to 8.

Each component contained in the developing ink composition of the present invention will be described in detail below.

The aqueous phase is water with a pH in the acidic range. Preferably, the aqueous phase further contains (e) a polyhydric alcohol and (f) at least one compound selected from the group consisting of alkali metal salts and ammonium salts.

The polyhydric alcohol as component (e) is a wetting agent that allows the developing ink composition of the present invention to dry at an appropriate speed on the lithographic printing plate, and also allows the developing ink composition to spread well on the plate surface. It is mainly responsible for the function of Preferred specific examples of such polyhydric alcohols include ethylene glycol,
Diethylene glycol, triethylene glycol, propylene glycol, butylene glycol, pentanediol, hexylene glycol,
Examples include tetraethylene glycol, polyethylene glycol, dipropylene glycol, tripropylene glycol, glycerin, sorbitol, and pentaesthritol, with glycerin being particularly preferred. The polyhydric alcohol as component (e) can be used alone or in combination of two or more, and should be contained in the developing ink composition of the present invention in an amount of about 1 to about 20% by weight based on the total weight. is suitable, and more preferably in a range of 5 to 10% by weight.

The alkali metal salt or ammonium salt, which is a compound of component (f) used in a preferred embodiment of the present invention, makes the non-image areas of the lithographic printing plate more hydrophilic, so that the oil phase of the developing ink remains in the non-image areas. This has the effect of preventing this from happening. Those that give particularly good results include water-soluble alkali metal and ammonium salts of acids such as acetic acid, molybdic acid, boric acid, nitric acid, sulfuric acid, phosphoric acid and polyphosphoric acid, specifically ammonium acetate, acetic acid Sodium, potassium acetate, sodium molybdate, potassium molybdate, sodium borate, ammonium borate, lithium nitrate, sodium nitrate, potassium nitrate, monobasic sodium phosphate, dibasic sodium phosphate, tribasic sodium phosphate, monobasic potassium phosphate, dibasic phosphate Potassium, potassium triphosphate,
Examples include triammonium phosphate, sodium polyphosphate, and the like. Among the above, particularly preferred are potassium acetate, sodium borate, ammonium borate, potassium nitrate, sodium molybdate, potassium molybdate, and potassium sulfate. The compound (f) can be used alone or in combination of two or more, and is added to the developing ink composition of the present invention in an amount of 0.1 to 10% by weight, preferably 0.2 to 5% by weight based on the total weight. It can be contained in

PH of the aqueous phase contained in the developing ink composition of the present invention
Even when it contains the above components (e) and (f), it is in the acidic range, more preferably PH 1 to 5, most preferably PH 2.
It should be adjusted to ~4. Therefore, if the pH of the dissolved components (e) and (f) is not in the acidic range, an acid is further added to bring the pH of the aqueous phase into the acidic range. Examples of acids that can be added as such PH adjusting agents include mineral acids such as phosphoric acid, sulfuric acid, and nitric acid, such as citric acid, phosphoric acid, malic acid,
Examples include organic acids such as glacial acetic acid, lactic acid, oxalic acid, and p-toluenesulfonic acid. This internal phosphoric acid not only functions as a pH adjuster but also has the effect of preventing stains in non-image areas, so it is particularly excellent.
The best effects are obtained when phosphoric acid is contained in an amount of 8% by weight, most preferably in the range of 0.5-5% by weight.

By further containing (e) a water-soluble polymer compound in the aqueous phase of the developing ink composition of the present invention, a developing ink composition having even more excellent performance can be obtained.
Preferred water-soluble polymer compounds include dextrin, gum arabic, alginates such as sodium alginate, celluloses such as carboxymethyl cellulose, hydroxyethyl cellulose, and methyl cellulose, polyvinyl alcohol, polyvinylpyrrolidone, polyacrylamide, and water-soluble polymers containing acrylamide units. copolymer,
Copolymers of vinyl methyl ether and maleic anhydride, and copolymers of vinyl acetate and maleic anhydride are included. Among these, particularly preferred are gum arabic, polyvinylpyrrolidone, carboxymethyl cellulose, and polyvinyl alcohol, and gum arabic is most preferred.

The above water-soluble polymer compound may be used alone or in combination.
The above can be used in combination, and the amount thereof can be within a range such that the viscosity of the aqueous phase is 5 to 300 centipoise, more specifically about 0.1 to about 25 centipoise based on the total weight of the developing ink composition. It is used in an amount of 1 to 20% by weight, preferably 1 to 20% by weight.

Next, the oil phase in the developing ink composition of the present invention will be explained.

The volatile solvent of component (a) can be one that is immiscible with water, but is more preferably selected from those that do not adversely affect the image area of the lithographic printing plate and have low toxicity. Preferred examples of such volatile solvents include turpentine, xylene, toluene, n-heptane, solvent naphtha, petroleum distillate hydrocarbon solvents with boiling points around 120°C to 250°C, such as kerosene, mineral spirits, etc. These can be used alone or in combination of two or more. In addition, together with these volatile solvents, ketones such as cyclohexanone and methyl ethyl ketone, glycol ethers such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, and ethylene glycol monophenyl ether, ethers such as phenyl glycol, e.g. Esters such as butyl acetate and amyl acetate, alcohols such as benzyl alcohol and amyl alcohol, and halogenated hydrocarbons such as ethylene chloride and trichloroethylene can be used in combination, thereby making the resin of component (b) It becomes easy to dissolve, or the aqueous phase and oil phase can be easily emulsified.

Component (a), the solvent, is used in an amount ranging from about 3 to about 30% by weight, more preferably from 5 to 25% by weight, based on the total weight of the developing ink composition of the present invention. Furthermore, the latter solvent (i.e., the solvent used in combination with the hydrocarbon solvent) is approximately 5% by weight based on the total weight of the solvent of component (a).
It is used in an amount of not more than 2% by weight, more preferably 2 to 3% by weight.

The lipophilic resin of component (b) may be any resin as long as it can be dissolved in the solvent of component (a), and those used as a vehicle in lithographic printing inks are particularly suitable. For example, rosin,
For example, modified rosins such as maleica rosin (rosin/maic anhydride adduct), water-added rosin, petroleum resins such as gilsonite, epoxy resins, polyvinyl formal, polyvinyl butyral, etc. can be used. Particularly useful binders are petroleum resins.

The resin of component (b) can be used alone or in combination of two or more, and the amount used is about 0.1 to about 10% by weight, more preferably 0.5% by weight based on the total weight of the developing ink composition of the present invention. ~8% by weight.

Component (c), the colorant, is produced by the oil phase contained in the developing ink of the present invention adhering to the image area of the lithographic printing plate.
They are used to provide visual contrast to non-image areas after the solvent in (a) has evaporated and can be selected from a wide range of dyes and pigments. A preferred example is carbon black.

Component (c), the colorant, is contained in the oil phase in such a range as to provide the desired concentration, but from about 0.5 to about 10% by weight based on the total weight of the developing ink composition of the present invention;
More preferably, it is used in a range of 1 to 7% by weight.

Component (d), the surfactant, is used to emulsify the aqueous phase and oil phase of the developing ink composition of the present invention to obtain a stable emulsion, but the surfactant substantially constitutes the oil phase. It can be said that it is one of the ingredients that Such surfactants can be used if their HLB value is in the range of 1 to 8. Among these, nonionic surfactants are excellent, and fatty acid esters of sorbitan are particularly excellent.
Specifically, sorbitan monolaurate, sorbitan monopalmylate, sorbitan monostearate, sorbitan trisstearate, sorbitan monooleate, sorbitan triolate, etc. can be mentioned, and among these, sorbitan monostearate is particularly effective. It has excellent effects.

Other preferred examples include polyoxyethylene higher alcohol ether condensates. By using it together with the fatty acid ester of sorbitan mentioned above in small amounts, for example in the range of about 0.1 to about 5% by weight based on the total weight of both, the stability of the emulsion which is the developing ink composition of the present invention can be improved. This can be further improved.

In addition to the above-mentioned components, the oil phase of the present invention includes plasticizers such as dihexyl phthalate and dioctyl phthalate, fats and oils such as beef tallow, such as oleic acid, lauric acid, valeric acid, nonylic acid, capric acid, Organic carboxylic acids having 5 to 25 carbon atoms such as mystilic acid and palmitic acid may be contained alone or in combination. These compounds have the effect of preventing the image areas of the printing plate from being adversely affected by the developing ink composition of the present invention. Therefore, when the developing ink composition of the present invention is applied to a lithographic printing plate having an image area particularly susceptible to adverse effects, it is preferable to include the above-mentioned compound. These compounds may be present in an amount of about 0.05 to about 8 based on the total weight of the developing ink composition of the present invention.
It can be used in an amount of 0.1 to 5% by weight.

Next, a typical method for preparing the developing ink composition of the present invention will be explained. Add acid first to desired pH
water or polyhydric alcohol of component (e), component (f)
The aqueous phase of the developing ink composition of the present invention is prepared by dissolving the compound and component (g) in water, and adding a PH adjuster if necessary. Separately, the solvent for component (a) contains the component
Dissolve the resin (b) and add the coloring agent (c) and the ingredients.
After adding the surfactant (d), mix thoroughly using a ball mill, roll mill, colloid mill, etc. to prepare an oil phase. The oil phase is added dropwise to the aqueous phase while stirring with a stirrer to obtain a dispersion, which is further emulsified with a homogenizer, thus obtaining the developing ink composition of the present invention.

The developing ink composition of the present invention can be effectively used for lithographic printing plates obtained by any method, but in particular, it can be used for photosensitive printing plates (presensitized plates, etc.) having an aluminum plate as a support. Particularly excellent effects can be obtained when using a lithographic printing plate obtained by imagewise exposure and development. It takes
A preferred PS version is, for example, British Patent No.
1350521, a photosensitive layer made of a mixture of a diazo resin (a salt of a condensate of p-diazodiphenylamine and formaldehyde) and silica is provided on an aluminum plate, British Patent No. A photosensitive layer made of a mixture of a diazo resin and a polymer having hydroxyethyl methacrylate units or hydroxyethyl acrylate units as main repeating units as described in the specifications of No. 1460978 and No. 1505739 is placed on an aluminum plate. Negative PS version like the one provided,
Also included is a positive-working PS plate in which a photosensitive layer made of a mixture of an 0-quinone diazide photosensitive material and a novolac type phenol resin is provided on an aluminum plate, as described in Japanese Patent Application Laid-open No. 125806/1983. Further, PS plates in which a photosensitive layer of a photocrosslinkable photopolymer is provided on an aluminum plate as specifically shown in US Pat. No. 3,860,426, and each of US Pat. No. 4,072,528 and US Pat. No. 4,072,527 A PS plate in which a photosensitive layer of a photopolymerizable photopolymer composition as described in the specification is provided on an aluminum plate, a PS plate as described in the specifications of British Patent No. 1235281 and British Patent No. 1495861; 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.

Next, an example of the use of the developing ink composition of the present invention in the case of using a PS plate 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 the water on the plate surface, an appropriate amount of the developing ink composition of the present invention is poured onto the plate surface, and the developing ink composition is rubbed with a sponge so as to coat the entire surface of the plate.
As a result, the oil phase of the developing ink composition uniformly adheres only to the image area on the printing plate, and the solvent of the oil phase evaporates, making the image area visible. Next, the printing plate is washed with water to complete the treatment process with the developing ink composition.
After this, if necessary, erase unnecessary image areas formed on the plate surface, and if printing will not start immediately, protect non-image areas by applying an aqueous solution of gum arabic, for example, and store the lithographic printing plate. be done. On the other hand, when starting printing immediately, the above component (a)
The developing ink adhering to the image area is removed using a solvent, etc., and printing is then started according to the normal procedure.

The developing ink composition of the present invention has the following features.

(1) There is no occurrence of karami. In particular, halftone image areas on planographic printing plates corresponding to areas with high image density in printed matter (in this area, the area of the non-image area per unit area is much smaller than that of the image area, and smearing is likely to occur). ) also has excellent performance in that there is no occurrence of scorch.

(2) Provide a visible image that faithfully reproduces the image area on the lithographic printing plate. Therefore, it is advantageous to examine the quality of the finished planographic printing plate by enlarging and observing the halftone image of the planographic printing plate using a magnifying glass or the like.

(3) Even if stored for a long time, the aqueous phase and oil phase will not separate and there will be no deterioration in performance.

(4) When applying it to the lithographic printing plate, it can be applied using a sponge, which makes the operation easy and improves work efficiency.

(5) It does not have an adverse effect on either the image area or the non-image area of the lithographic printing plate. For example, the printing ink receptivity of the image area does not deteriorate, and the non-image area does not become easily stained with printing ink.

Hereinafter, the present invention will be explained in more detail based on examples. In addition, "part" shall mean "part by weight."

Example 1 10 parts of petroleum resin (Petrozin #80 manufactured by Mitsui Petrochemicals, Inc.) was dissolved in a mixed solvent of 155 parts of turpentine oil and 30 parts of cyclohexanone. In this solution, 15 parts of sorbitan monostearate (trade name Span 60, manufactured by Kao Atlas Co., Ltd.) and 5 parts of sorbitan monooleate (trade name Nonion OP-80, manufactured by Nippon Oil & Fats Co., Ltd.) were dissolved in a porcelain container. and then asphalt powder 20
and 15 parts of carbon black were added and ball milled for 20 to 24 hours (Dispersion A).

Separately, dissolve 2 parts of carboxymethyl cellulose (Celogen 7A, Daiichi Kogyo Seiyaku Co., Ltd.) in 66.4 parts of water, mix with 5 parts of glycerin, and add 1 part of phosphoric acid (85% by weight).
1 part, 0.5 part of monobasic sodium phosphate and 0.5 part of ammonium acetate were dissolved (aqueous solution B).

While stirring the aqueous solution B (total amount) with a stirrer,
After slowly dropping and dispersing 25 parts of the completely dispersed dispersion liquid A, the mixture was passed through a homogenizer to form an emulsion, thereby producing the developing ink composition (1) of the present invention.

Japanese Unexamined Patent Publication No. 125806/1973 (Patent Application No. 33264/1973)
The positive-working photosensitive lithographic printing plate described in Example 1 of No. 1) was imagewise exposed, developed, and washed with water in the same manner as described in Example 1. A small amount of the above-mentioned developing ink composition was dropped onto the lithographic printing plate, and spread over the entire surface of the plate using a sponge. Upon subsequent washing with water, the developing ink composition in the non-image areas was washed away, and the oil phase of the developing ink composition was deposited only in the image areas, forming a black image on the white background of the aluminum.

There were no blemishes, and the original painting was faithfully reproduced. This plate was coated with a 14°Be' gum arabic aqueous solution, buff-dried, and stored for one month. After washing the preserved plate with water to remove gum arabic, and then using solvent naphtha to remove the developing ink adhering to the image area, this plate was installed in a printing machine and printed. A print was obtained. Place 1 of the above developing ink composition (1) in a sealed container.
I used it after storing it for a year and got exactly the same results.

Example 2 Both solutions with the following formulations were prepared in the same manner as in Example 1 to obtain a developing ink composition (2) of the present invention.

Solvent phase Turpentine 7.0 parts Toluene 8.0 parts Sorbitan monostearate (span-60,
Kao Atlas Co., Ltd.) 2.0 parts Sorbitan Tristearate (Span-65,
Kao Atlas Co., Ltd.) 0.3 parts petroleum resin (Petrogin #120, Mitsui Petrochemical
Co., Ltd.) 1.5 parts Rosin 0.5 parts Asphalt powder 1.0 parts Carbon black 2.2 parts Aqueous phase Part Water 60.0 parts Glycerin 5.0 parts Gum arabic 10.0 parts Phosphoric acid (85% by weight) 2.0 parts Sodium borate 0.5 parts This developing ink composition ( 2) was used on a lithographic printing plate obtained in the same manner as in Example 1, and results exactly the same as in Example 1 were obtained.

Example 3 A developing ink composition (3) having the following composition was prepared in the same manner as in Example 1.

Solvent phase solvent naphtha 15 parts ethylene glycol monophenyl ether
Tripartite sorbitan monostearate (Solgen)
50, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) 1.5 parts Sorbitan monooleate (Sorgen-80, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) 0.3 parts Petrozine #80 (see Example 1) 1.5 parts Hydrogenated rosin modified resin (Harcolin ) 0.5 parts Asphalt powder 1.0 parts Carbon black 3.0 parts Lauric acid 0.2 parts Aqueous phase Part Water 59.9 parts Glycerin 8 parts Polyvinylpyrrolidone-K30 4 parts Phosphoric acid (85% by weight) 3 parts Potassium nitrate 0.3 parts Sodium molybdate 0.3 parts JP-A-Sho Publication No. 50-118802 (Patent application 1972-23940)
The above developing ink composition was applied to the lithographic printing plate obtained by imagewise exposing and developing the negative photosensitive lithographic printing plate described in Example 1 of No. 1) by the method described in Example 1. Example 1
Similar results were obtained.

The same test was conducted using the developing ink composition (3) that had been stored for one year, but no change in performance was observed.

Example 4 In the same manner as in Example 1, a developing ink composition (4) having the following composition was obtained.

Solvent phase Part n-heptane 16.5 parts Cyclohexanone 3 parts Sorbitan monostearate (Sorgen-
50, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) 2 parts sorbitan sesquiolate (nonionic OP-
83, Nippon Oil & Fats Co., Ltd.) 0.2 parts petroleum resin (Petrogin #80, Mitsui Petrochemical Co., Ltd.)
1.8 parts Carbon black 3.0 parts Valeric acid 0.5 parts Aqueous phase Part Water 62.0 parts Polyvinyl alcohol (GH-17, Nippon Gosei)
Co., Ltd.) 2.0 parts Glycerin 5.0 parts Phosphoric acid (85% by weight) 3.0 parts Sodium sulfate 0.5 parts Potassium molybdate 0.5 parts The above developing ink composition ( 4), good results were obtained as in Example 1.

Example 5 A developing ink composition (5) having the following composition was obtained in the same manner as in Example 1.

Solvent phase: 1 part toluene 10 parts Petroleum distillate with a boiling point of 160 to 210°C (Swazole, manufactured by Maruzen Petrochemical Co., Ltd.) 5 parts ethylene glycol monophenyl ether
5 parts sorbitan monostearate (nonion sp
-60, manufactured by NOF Corporation) 1.8 parts Sorbitan monolaurate (Span-20, manufactured by Kao Atlas Co., Ltd.) 0.2 parts Oleic acid 1.0 parts Carbon black 4.0 parts Epoxy resin (#815, manufactured by Ciel Corporation) 0.3 parts Aqueous phase water 33.7 parts Glycerin 5.0 parts Gum Arabic (14°Be aqueous solution) 30.0 parts Phosphoric acid (85% by weight) 3.0 parts Ammonium borate 0.5 parts Potassium acetate 0.5 parts Lithographic printing plate used in Example 1 and Example 3 The above developing ink composition (5) was used for both of the lithographic printing plates obtained in Example 1.
Similar results were obtained.

Example 6 Positive PS sold by Kalle
A lithographic printing plate was obtained by making the plate Ozazol P-4 according to the method specified by the company. After washing this plate with water and removing excess water with a squeegee, the developing ink composition prepared in Example 2 was applied with a sponge.
Washed with water. The oil phase of the developing ink composition adhered neatly only to the image areas, while the non-image areas were free from stains due to adhesion of the developing ink composition.

This plate was coated with an aqueous solution of gum arabic in the same manner as in Example 1, stored for one month, washed with water, developed with turpentine oil, removed ink, and then mounted on a printing machine and printed. Good printed matter was obtained without any problems.

Example 7 The experiment was carried out in the same manner as in Example 6, except that a negative PS plate Ozazol N-21 manufactured by Carre was used, and the developing ink composition prepared in Example 4 was used.

Exactly the same results as in Example 6 were obtained.

Example 8 A developing ink composition of the present invention was obtained in the same manner as in Example 1, except that the aqueous phase had the following composition.

Aqueous phase water: 65.0 parts Gum arabic: 10.0 parts Citric acid: 2.0 parts When this developing ink composition was used on a lithographic printing plate obtained in the same manner as in Example 1, the results were almost the same as in Example 1. was gotten.

Claims (1)

[Claims] 1. An aqueous phase having a pH in the acidic range, and (a) a volatile solvent immiscible with water, (b) a lipophilic resin that can be dissolved in the volatile solvent, and (c) a coloring agent. and (d) an oil phase containing a surfactant having an HLB value of 1 to 8.