JP3052663B2 - Printing aid - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a printing aid. The present invention relates to a printing aid particularly useful as a plate surface protective agent, a plate surface cleaning agent, an image disinfectant, and the like.

[0002]

2. Description of the Related Art Lithographic printing is a printing method that makes effective use of the property that water and oil are not essentially mixed. The printing plate surface has a portion that receives water and repels oily ink, and a portion that repels water and repels oil. The former is formed from a non-image portion, and the latter is formed from an image portion.

Usually, lithographic printing plate auxiliaries such as a plate surface protective agent, a plate surface cleaning agent, an image erasing agent, a sensitizing protective agent and a gum remover are used to protect the non-image areas. As the auxiliary agent, a water-soluble polymer having a film forming property has been conventionally used as an essential component.

For example, in a final step of lithographic printing, a plate surface protective agent is applied (usually called gumming) to protect a non-image area.

[0005] The plate surface protective agent not only maintains the hydrophilicity of the non-image area by utilizing the film-forming properties, but also modifies the image area by adding or erasing, and preserves or reuses the period from plate making until printing. Used to prevent contamination caused by the attachment of fingerprints, oils and fats, dust, etc. during the storage and handling during installation on the printing press, to protect from scratching, etc., and to further suppress the occurrence of contamination due to oxidation. Can be

Heretofore, as such a plate surface protective agent, almost in general, an aqueous solution of gum arabic, cellulose gum or a water-soluble polymer having a carboxyl group in a molecule has been used. Those containing agents and the like have been used.

[0007] When gum arabic, which is a natural plant gum, is used as the water-soluble polymer for such a plate surface protective agent, gum arabic exhibits excellent film-forming properties.

On the other hand, as is well known, when making a photosensitive lithographic printing plate, a so-called image erasing operation for removing an unnecessary image is performed after the image forming step. Particularly in the case of a positive planographic printing plate, an unnecessary image is easily generated due to a foreign matter such as an edge mark of a film original plate or dust, so that an image erasing operation is an essential step.

[0009] In such an image erasing operation of a lithographic printing plate, the surface of the support from which the image has been removed must be made hydrophilic at the same time as the removal of the unnecessary image so that the ink is not accepted during printing. However, there are very few known effective erasure methods therefor.

For example, a method of physically shaving off unnecessary images with a stone stick, a method of corroding and removing an image and a support with a strong alkaline solution, or a method of dissolving an image with an organic solvent capable of dissolving the image and hydrofluoric acid. There is a method in which an unnecessary image is dissolved by a solution containing an acidic substance, and at the same time, the support is corroded to make it hydrophilic. Although these methods are effective, the former method has a drawback that a large area cannot be processed or stains occur at the time of printing, and the latter two methods may damage a required image in a fine portion. This method is not always satisfactory because it has several drawbacks, such as high risk to human body or skin, and problems with wastewater treatment.

Recently, a method using an image erasing agent containing a water-soluble polymer, an organic solvent, a surfactant and a mineral acid has been exclusively adopted as an effective method for solving the above-mentioned disadvantages. In the method using the image erasing agent, when natural gum arabic, which is a vegetable gum, is used as the water-soluble polymer, the gum arabic exhibits excellent suitability for forming a film.

[0012] In addition, as described above, gum arabic can also be used in the case where gum arabic is used as a water-soluble polymer used in a plate surface washing agent, a sensitizing protective agent or a gum remover for protecting non-image areas. Shows excellent suitability for film formation.

In order to perform lithographic printing, a fountain solution for lithographic printing is used. The fountain solution for lithographic printing wets the non-image area, thereby increasing the surface chemistry difference between the image area and the non-image area to increase the ink repellency of the non-image area and the ink receptivity of the image area. It has a function to make it work.

In such a fountain solution for lithographic printing, a water-soluble polymer having a film-forming ability is used as an essential component. When gum arabic, which is a natural plant gum, is used as the water-soluble polymer, gum arabic exhibits excellent suitability for forming a film as a fountain solution for lithographic printing.

As described above, gum arabic, which has been conventionally used as a water-soluble polymer in a lithographic printing aid, shows excellent suitability in any case, but its supply amount is easily affected by the weather in the producing country. Therefore, the price fluctuates drastically, and a natural vegetable gum that can be stably supplied has recently been desired.

As a substitute for gum arabic, a modified starch such as a modified starch has been developed, but it has a disadvantage that the non-image area has a poor desensitizing power and is not always satisfactory.

[0017]

SUMMARY OF THE INVENTION An object of the present invention is to provide a printing aid which has a stable film forming property over a long period of time, is inexpensive and can be supplied stably.

[0018]

Means for Solving the Problems As a result of intensive studies in view of the above points, the present inventors have found that when water-soluble hemicellulose derived from soybean is used as a water-soluble polymer component used for a lithographic printing aid, It has been found that a lithographic printing aid having a strong film-forming property can be obtained. The present invention has been completed based on such findings.

Accordingly, the present invention provides a printing aid comprising a water-soluble soybean-derived hemicellulose as an active ingredient.

The water-soluble hemicellulose in the present invention is preferably derived from beans, particularly soybeans, and especially from cotyledons.

The water-soluble hemicellulose may have any molecular weight, but preferably has an average molecular weight of tens of thousands to several millions, specifically 50,000 to 1,000,000. . The average molecular weight of this water-soluble hemicellulose is a value determined by an intrinsic viscosity method using a standard pullulan (available from Showa Denko KK) as a standard substance and measuring the viscosity in a 0.1 M NaNO3 solution. Also, uronic acid is measured by Blumenk
The neutral sugar was measured by GLC (gas-liquid chromatography) after alditol acetate conversion.

The water-soluble hemicellulose can be obtained by extracting with water from a raw material containing hemicellulose, or in some cases by heating and eluting under acid or alkaline conditions, or by decomposing and eluting with an enzyme. An example of a method for producing water-soluble hemicellulose is as follows.

Oil seeds, such as soybean, palm, palm, corn, cottonseed, etc., are usually made of shells from which oils and fats have been removed, or cereals, such as rice, wheat, etc., and plants, such as lees, from which starches are usually removed. be able to. If the raw material is soybean, it is possible to use okara which is a by-product when producing tofu, soymilk, and isolated soybean protein.

These raw materials are thermally decomposed under acidic or alkaline conditions, preferably at a pH near the isoelectric point of each protein, preferably at 130 ° C or lower and 80 ° C or higher, more preferably 130 ° C or lower and 100 ° C or higher. Then, the water-soluble fraction is fractionated and then dried as it is, or, for example, activated carbon treatment, resin adsorption treatment or ethanol precipitation treatment to remove a hydrophobic substance or a low-molecular substance, followed by drying to obtain a water-soluble hemicellulose. be able to.

When such a water-soluble hemicellulose is used as a lithographic printing plate aid and a water-soluble polymer which is a raw material of a fountain solution for lithographic printing, the use of gum arabic and modified starch is more effective. A film formation state with excellent stability is obtained. In addition, when the lithographic printing plate aid is in an emulsified state, than when gum arabic or modified starch is used,
Further, a product having excellent emulsifiability can be obtained.

In the present invention, water-soluble hemicellulose can be used alone as a water-soluble polymer, but by using it in combination with an existing water-soluble polymer, the drawbacks of the existing water-soluble polymer can be compensated. .

Existing natural product water-soluble polymers include gum arabic, tragacanth gum, carrageenan, xanthan gum, gelatin, sodium caseinate, guar gum,
Examples include tara gum, cloth nori, agar, furceleran, tamarind seed polysaccharide, karaya gum, trollooi, pectin, sodium alginate, pullulan, gellan gum, locust bean gum, albumin such as whey, various starches, and the like.

On the other hand, as semi-natural water-soluble polymers, modified starches represented by carboxymethyl cellulose (CMC), methyl cellulose (MC), ethyl cellulose (EC), hydroxyethyl cellulose (HEC), propylene glycol alginate, and soluble starch Etc.

The existing synthetic water-soluble polymers include polyethylene glycol and its copolymer, polyvinyl alcohol and its copolymer, polyvinylpyrrolidone, polyacrylamide and its copolymer, polyacrylic acid and its copolymer. And vinyl methyl ether-maleic anhydride copolymer, vinyl acetate-maleic anhydride copolymer, polystyrene sulfonic acid and copolymers thereof.

The water-soluble hemicellulose in the present invention comprises:
In some cases, the effect can be further improved by using one or more of the above-mentioned various water-soluble polymers in combination, and the drawbacks of the various water-soluble polymers can be compensated.

When the water-soluble hemicellulose used in the present invention is used as a plate surface protective agent for a lithographic printing plate, the amount of the water-soluble hemicellulose is suitably 0.1 to 35% by weight based on the total amount of the plate surface protective agent, more preferably 0.3 to 25% by weight. %.

The plate surface protective agent is generally used in an acidic region, that is, a pH range.
It is advantageous to use a value in the range from 3 to 6. In order to adjust the pH value of the plate surface protective agent to a range of 3 to 6, it is appropriate to use a mineral acid, an organic acid, an inorganic salt or the like in the protective agent.

Preferred mineral acids include sulfuric acid, nitric acid, phosphoric acid, and metharin. Examples of organic acids include acetic acid, citric acid, oxalic acid, malonic acid, p-toluenesulfonic acid, tartaric acid, malic acid, lactic acid, and levulinic acid. , Organic sulfonic acid, ascorbic acid, gluconic acid, hydroxyacetic acid, sulfanilic acid, phytic acid and the like are useful. Further, alkali metal salts, alkaline earth metal salts, and ammonium salts of these mineral acids and organic acids are preferably used. At least one kind or two or more kinds of mineral acids, organic acids, and salts thereof may be used in combination.

Further, a surfactant can be added to the plate surface protective agent of the present invention for the purpose of improving the surface condition of the coating film.

The surfactant which can be used includes an anionic surfactant and a nonionic surfactant. Examples of the anionic surfactant include aliphatic alcohol sulfates, aliphatic alcohol phosphates, sulfonates of dibasic fatty acid esters, fatty acid amide sulfonates, alkylaryl sulfonates, formaldehyde condensed naphthalene sulfonates, and the like. There are, as nonionic surfactants, polyethylene glycol alkyl ether, polyethylene glycol alkyl ester,
Sorbitan alkyl esters, polyoxypropylene polyoxyethylene ethers and the like are used. Two or more surfactants may be used in combination. The amount used is not particularly limited, but is preferably added in the range of 0.01 to 10% by weight of the plate surface protective agent.

[0036] In addition to the above components, wetting agents, preservatives and the like can be added as necessary. Lower polyhydric alcohols such as glycerin, ethylene glycol and triethylene glycol can also be used as wetting agents. The use amount of these wetting agents is suitably from 0.1 to 5% by weight of the plate surface protective agent, and a more preferred range is from 0.5 to 3% by weight. Benzoic acid and its derivatives, phenol, formalin and sodium dehydroacetate are used as preservatives in an amount of 0.005 to 2
It can be added in the range of weight%.

The plate surface protective agent of the present invention can be used for various lithographic printing plates. In particular, a photosensitive lithographic printing plate (PS plate) having an aluminum plate as a support and having a photosensitive layer thereon Can be suitably used for a lithographic printing plate obtained by image exposure and development.

When the water-soluble hemicellulose in the present invention is used as an image erasing agent for a lithographic printing plate, the content of the water-soluble polymer in the image erasing agent is suitably from 0.1 to 5% by weight, and a more preferable range is 0.5 to 3% by weight.

The organic solvent used in the image erasing agent of the present invention dissolves or swells the photosensitive layer to which the erasing agent is applied, and the ketones include acetone, methyl ethyl ketone, methyl isopropyl ketone, diisobutyl ketone, and cyclohexanone. Hydrocarbons such as benzene, toluene and xylene; ethers such as methyl glycol, ethyl glycol and butyl glycol;
Examples of esters include methyl glycol acetate and ethyl glycol acetate, and examples of aromatic alcohols include propyl alcohol, butyl alcohol, benzyl alcohol, and ethylene glycol, and organic solvents such as dimethylformamide and butyrolactone. A mixture of more than one species is used.

Of these organic solvents, dimethylformamide, cyclohexanone, xylene, ethyl glycol acetate and the like are preferred.

The organic solvent is used in the range of 50 to 90% by weight, and more preferably in the range of 60 to 80% by weight, in the image erasing agent.

Examples of the surfactant used in the present invention include known nonionic surfactants, anionic surfactants, cationic surfactants, and amphoteric surfactants. Among them, these are dissolved or dispersed in an organic solvent used. You can choose what you want to use.

Particularly preferred are nonionic surfactants, such as polyoxyethylene alkyl ether, polyoxyethylene alkyl allyl ether, polyoxyethylene alkyl ester, polyoxyethylene sorbitan alkyl ester, and polyoxyethylene polyoxypropylene. And polymers. Surfactants may be used in combination of at least one kind or two or more kinds. The content of the surfactant is 3 to 20% by weight, preferably 5 to 15% by weight in the image erasing agent.

The image erasing agent is generally used in an acidic region, ie, a pH range.
It is advantageous to use a value in the range from 3 to 6. In order to adjust the pH value of the image erasing agent to a range of 3 to 6, it is appropriate to use a mineral acid, an organic acid, an inorganic salt or the like in the erasing agent.

As the above-mentioned various acids and salts, it is appropriate to use those exemplified for pH adjustment in the above-mentioned plate surface protective agent. In addition to the above components, a dye, a thickener and the like can be added as necessary.

The image erasing agent of the present invention can be easily prepared by mixing the above-mentioned various components. The purpose of the prepared image erasing agent can be easily achieved by including it in a brush or the like and applying it to a required portion of the image to be erased, and then washing with water. Further, it is possible to prevent the erased image from being recontaminated during printing.

The lithographic printing plate that has been treated with the image erasing agent of the present invention can maintain a good storage state thereafter by applying a plate surface protective agent, ie, by gumming.

The image erasing agent of the present invention can be used for both negative-working and positive-working lithographic printing plates, and can be suitably used particularly for positive-working lithographic printing plates.

When the water-soluble hemicellulose in the present invention is used in a fountain solution composition for lithographic printing, the amount of the water-soluble hemicellulose is suitably 0.001 to 10% by weight based on the total amount of the fountain solution composition, and more preferably in the range. Is 0.005 to 1% by weight.

As the pH buffer substance contained in the fountain solution composition of the present invention, a mineral acid, an organic acid or a salt thereof can be used.
It is effective for moderate edging and anticorrosion of the lithographic printing plate support.

The addition amount of the pH buffer substance is preferably in the range of 0.001 to 1% by weight, and is preferably used in an acidic region having a pH value of 3 to 7, but may be an alkali metal hydroxide, an alkali metal phosphate, It can also be used in an alkali region having a pH value of 7 to 11 containing an alkali metal carbonate, a silicate or the like.

The fountain solution composition of the present invention may contain a solvent, a humectant, a preservative, an antifoaming agent and the like, if necessary.

Specific examples of the wetting agent include polyols, glycol ethers, alcohols and surfactants. For example, polyol and glycol ether are 2
-Ethyl-1,3-hexadiol, hexyl carbitol, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, hexylene glycol, tetraethylene glycol, 1,5-
Pentadiol, hexyl cellosolve, glycerin, diglycerin, ethylene glycol monomethyl ether,
Diethylene glycol monomethyl ether, triethylene glycol monomethyl ether, polyethylene glycol monomethyl ether, propylene glycol monomethyl ether, dipropylene glycol monomethyl ether, ethylene glycol monopropyl ether, diethylene glycol monopropyl ether, propylene glycol monopropyl ether, dipropylene glycol monopropyl ether, Ethylene glycol monoisopropyl ether, diethylene glycol monoisopropyl ether, ethylene glycol monobutyl ether, diethylene glycol monobutyl ether, triethylene glycol monobutyl ether, propylene glycol monobutyl ether, dipropylene glycol monobutyl ether, Polypropylene glycol (molecular weight
200-10000), ethylene glycol monoisobutyl ether, diethylene glycol monoisobutyl ether, ethylene glycol monoallyl ether, ethylene glycol monophenyl ether, diethylene glycol monophenyl ether, ethylene oxide adduct of 2-ethyl-1,3-hexadiol, Examples include acetylene glycol and its ethylene oxide adduct.

As the alcohol, ethyl alcohol,
n-propyl alcohol, isopropyl alcohol, n
-Butyl alcohol, isobutyl alcohol, n-amyl alcohol, benzyl alcohol and the like.

As the surfactant, an anionic surfactant,
Nonionic surfactants and cationic surfactants are exemplified.

As the anionic surfactant, fatty acid salts,
Abietate, alkane sulfonate, hydroxyalkane sulfonate, dialkyl sulfosuccinate, linear alkylbenzene sulfonate, branched alkylbenzene sulfonate, alkyl naphthalene sulfonate,
Alkylphenoxy polyoxyethylene propyl sulfonate, polyoxyethylene alkyl sulfophenyl ether salt, N-methyl-N-oleyltaurine sodium salt, N-alkyl sulfosuccinic acid monoamide disodium salt, petroleum sulfonate, sulfated castor oil, Sulfated tallow oil, sulfate of fatty acid alkyl ester, alkyl sulfate, polyoxyethylene alkyl ether sulfate, fatty acid monoglyceride sulfate, polyoxyethylene alkyl phenyl ether sulfate, polyoxyethylene styryl phenyl ether sulfate Ester salt, alkyl phosphate ester salt, polyoxyethylene alkyl ether phosphate ester salt,
Examples thereof include polyoxyethylene alkylphenyl ether phosphate ester salts, partially saponified styrene-maleic anhydride copolymers, partially saponified olefin-maleic anhydride copolymers, and naphthalene sulfonate formalin condensates.

Of these, dialkyl sulfosuccinates, alkyl sulfates and alkyl naphthalene sulfonates are preferred.

Examples of the nonionic surfactant include polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, polyoxyethylene polystyryl phenyl ether, polyoxyethylene polyoxypropylene alkyl ether, glycerin fatty acid partial ester, and sorbitan fatty acid partial ester. Pentaerythritol fatty acid partial ester, propylene glycol monofatty acid ester, sucrose fatty acid partial ester, polyoxyethylene sorbitan fatty acid partial ester, polyoxyethylene sorbitol fatty acid partial ester, polyethylene glycol fatty acid ester, polyglycerin fatty acid partial ester, polyoxy Ethylene castor oil, polyoxyethylene glycerin fatty acid partial ester, fatty acid diethanolamide, N N- bis-2-hydroxyalkylamines, polyoxyethylene alkylamines, triethanolamine fatty acid esters, trialkylamine oxides and the like.

Of these, polyoxyethylene alkylphenyl ether, polyoxypropylene block polymer and the like are preferred. As the anionic surfactant,
Examples thereof include an alkylamine salt, a quaternary ammonium salt, a polyoxyethylene alkylamine salt, and a polyethylene polyamine derivative.

These wetting agents can be used alone or in combination of two or more, preferably 0.03 to 5% by weight, more preferably 0.05 to 5% by weight, based on the total weight of the fountain solution composition.
It is appropriate to use 3% by weight.

Specific examples of preservatives usable in the present invention include phenol and its derivatives, imidazole derivatives, formalin, sodium dehydroacetate, 4-isothiazolin-3-one derivatives, benzotriazole derivatives, amidizing anidine derivatives, and quaternary ammonium. Preferred are salts, derivatives such as pyridine, quinoline and guanidine, diazines, triazole derivatives, oxazoles, oxazine derivatives and the like.

The preservative is added in such an amount that it can exert its effect stably on bacteria, mold, yeast and the like.
Although it depends on the type of microorganism such as mold and yeast, it is preferably 0.001 to 1 based on the total weight of the fountain solution composition at the time of use.
%, And it is preferable to use two or more preservatives in combination so as to obtain an effect on various microorganisms such as bacteria, molds, and yeasts.

As the defoaming agent which can be used in the present invention, any defoaming agent can be used as long as it has a defoaming effect, but a silicon-based compound is preferable. Silicon-based compounds include emulsified type and one-pack type, but both exhibit effective effects with small amounts, so the amount of defoamer used is 0.001 with respect to the total weight of the fountain solution composition at the time of use.
A range of .about.0.3% by weight is preferred.

A chelating compound may be added to the fountain solution composition of the present invention, if necessary, in addition to the above compounds. The purpose of adding the chelate compound is to eliminate the drawback that tap water used for dilution when using the dampening solution composition, calcium ions and the like contained in well water and the like adversely affect printing. is there.

The chelate compound which can be suitably used is not particularly limited as long as it is stably present in the fountain solution composition and does not inhibit printability. Specific examples thereof include ethylenediaminetetraacetic acid and potassium salt of ethylenediaminetetraacetic acid. , The sodium salt of ethylenediaminetetraacetic acid,
Diethylenetriaminepentaacetic acid, potassium salt of diethylenetriaminepentaacetic acid, sodium salt of diethylenetriaminepentaacetic acid, triethylenetetraminehexaacetic acid, potassium salt of triethylenetetraminehexaacetic acid, sodium salt of triethylenetetraminehexaacetic acid, hydroxyethylethylenediaminetriacetic acid, hydroxyethyl Potassium salt of ethylenediaminetriacetic acid,
Hydroxyethylethylenediaminetriacetic acid sodium salt, nitrilotriacetic acid, nitrilotriacetic acid sodium salt, 1-hydroxyethane 1,1-diphosphonic acid,
-Hydroxyethane 1,1-diphosphonic acid potassium salt, 1-hydroxyethane 1,1-diphosphonic acid sodium salt, aminotri (methylenephosphonic acid), aminotri (methylenephosphonic acid) potassium salt, aminotri (methylenephosphonic acid) Organic phosphonic acid or phosphonoalkanetricarboxylic acid such as sodium salt of Also, instead of the above-mentioned potassium salts and sodium salts of the chelate compounds, salts of organic amines are also suitable.

The addition amount of these chelate compounds is preferably 0.001 to 0.001 to the total weight of the fountain solution composition at the time of use.
It is in the range of 5% by weight, more preferably in the range of 0.005 to 1% by weight.

In the fountain solution composition of the present invention, various colorants, rust inhibitors, antioxidant agents for non-image areas, etc. are stably present in the fountain solution composition and do not impair printability. Can be added.

Examples of the coloring agent that can be preferably used include food coloring matters, and specific examples thereof include CI No. 1 as a yellow coloring matter. 19140, 15985, CI Red No. 16185, 45430, 16255,
45380, 45100, CI N as blue pigment
o. 42090, 73015, CIN as green pigment
o. 42095 and the like.

As rust preventives that can be suitably used, benzotriazole, tolyltriazole, benzimidazole and 2-mercaptobenzimidazole can be mentioned.
As the oxidation stain preventive agent for the non-image area that can be suitably used,
Zinc nitrate, magnesium nitrate, sodium nitrate and the like.

The method of preparing the fountain solution composition of the present invention as a concentrated solution, and diluting it with tap water, well water or the like 10- to 1000-fold at the time of use is economical and preferred.

The lithographic printing plate using the fountain solution composition of the present invention includes a photosensitive lithographic printing plate (PS plate), a lithographic printing plate, a bimetallic metal plate, a bimetallic metal plate, a trimetallic metal plate, a direct drawing master, and an electrophotographic lithographic plate. Various lithographic printing plates such as printing plates can be used.

[0072]

The embodiments of the present invention will be described below with reference to examples, but these are only examples, and the spirit of the present invention is not limited by these examples. In addition, in an example, all parts and% mean a weight basis.

Preparation of soybean hemicellulose Two times the amount of water was added to the raw okara obtained in the isolated soybean protein production process, and the pH was adjusted to 4.5 with hydrochloric acid.
Hydrolyzed for 5 hours. After cooling, centrifuge (10000 G x 30
Min), and separated into a supernatant and a precipitate. The precipitate thus separated was further washed with water of an equal weight, centrifuged, and the supernatant was treated with an activated carbon column together with the supernatant, followed by drying to obtain water-soluble hemicellulose (a).

Further, 0.5% of this water-soluble hemicellulose was added.
It was dissolved in saline and the reprecipitation was repeated three times so that the ethanol concentration became 50%. The ion exchange resin (Organo Co., Ltd.)
Desalted using "Amberlite IR-120 B", manufactured by Toshiba, to obtain water-soluble hemicellulose (b).

On the other hand, a water-soluble hemicellulose (c) was obtained in the same manner as described above without treatment with an activated carbon column.

The above results are summarized as follows. Composition ratio (%)----------------------------------------------------------------------------- ) −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−− Water 5.71 7.75 5.10 Crude protein 1.93 1.03 5.43 Crude ash 5.29 0.22 5.30 Many Saccharides 87.07 91.00 84.17 --- --- ----------------Average molecular weight 178,000 207,000 114,000------ −−−−−−−−−−−−−−−−−−−−−−−−−−−−−

Next, the sugar composition of the water-soluble hemicellulose of (a), (b) and (c) was analyzed by the following method. Uronic acid was measured by the Blumenkrantz method, and neutral sugar was measured by the alditol acetate method using GLC.

The results are as follows. Sugar composition (% by weight)----------------------type of sugar (a) (b) (C) −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−− uronic acid 20.4 16.9 19.4 rhamnose 1.6 2.7 2.1 fucose 2.7 5.2 3.9 arabinose 19.9 19.2 23.1 Xylose 6.4 8.4 5.8 Galactose 47.3 46.8 43.4 Glucose 1.8 0.9 2.3 −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−

Example 1 Water-soluble soybean hemicellulose (a) 10.0 parts 40% aqueous solution of anionic surfactant * 0.5 part Sodium dehydroacetate 0.1 part Phosphoric acid (85%) 0.3 part Pure water 89. 1 part-----------------------sodium dialkyl diphenyl ether disulfonate (manufactured by Sanyo Chemical Co., Ltd.) The mixture was uniformly mixed to obtain a lithographic printing plate surface protective agent.

Example 2 A plate surface protective agent was obtained in the same manner as in Example 1 except that water-soluble soybean hemicellulose (a) was used instead of water-soluble soybean hemicellulose (a).

Example 3 A plate surface protective agent was obtained in exactly the same manner as in Example 1 except that water-soluble soybean hemicellulose (C) was used instead of water-soluble soybean hemicellulose (A).

Comparative Example 1 A plate surface protective agent was obtained in the same manner as in Example 1 except that gum arabic was used instead of water-soluble soybean hemicellulose (a).

Comparative Example 2 A plate surface protective agent was obtained in exactly the same manner as in Comparative Example 1, except that dextrin was used instead of gum arabic.

In order to evaluate the effects of the plate surface protective agents obtained in the above Examples and Comparative Examples, photosensitive lithographic printing plates were prepared.

That is, an aluminum plate having a thickness of 0.241 mm was
It was immersed in a 7% aqueous solution of tribasic sodium phosphate at 60 ° C., degreased, washed with water, and rubbed with a nylon brush while pouring pumice in a liquid suspended in water. Potassium silicate kept at 70 ° C after water washing (SiO2 / K2O molar ratio 2.0)
Was immersed in a 5% aqueous solution for 30 to 60 seconds, washed sufficiently with water, and dried.

6.2 parts of 2-hydroxyethyl methacrylate copolymer (synthesized by the method of Example 1 in British Patent No. 1505739), 2-methoxy-condensate of p-diazodiphenylamine and paraformaldehyde
A photosensitive solution comprising 0.4 parts of 4-hydroxy-5-benzoylbenzenesulfonate, 0.1 part of Oil Blue # 603 (manufactured by Orient Chemical Industry Co., Ltd.), 46.7 parts of 2-methoxyethanol, 31.1 parts of methanol, and 15.5 parts of ethylene chloride was used. The composition was applied to the above support to obtain a photosensitive lithographic printing plate having a coating dry weight of 1.8 g / m2.

The printing plate was exposed to light using a dot negative film, and 0.3 parts of sodium sulfite and benzyl alcohol 2.
The film was developed with an aqueous developer comprising 8 parts, 1.9 parts of triethanolamine, 0.5 parts of monoethanolamine, 1.0 part of sodium t-butylnaphthalenesulfonate and 93.5 parts of pure water, washed with water and dried.

The printing plate was divided into six parts, and the plate surface protective agents obtained in Examples and Comparative Examples were applied to five of these plates, and excess was wiped off with a cloth. No plate surface protective agent was used for the remaining one printing plate.

After storing these samples in a thermo-hygrostat at a temperature of 45 ° C. and a humidity of 85% for 3 days, Heidelberg KOR-D was used.
Printing was carried out on a printing press according to the usual method. Observations were made on the number of defective prints until a clear print was obtained and on the ease of contamination during printing.

The results are shown below in comparison. Easiness of smearing until a clear print is obtained * Number of defective prints-----------------------------Examples 1 12 ○ −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−− Example 2 18 ○ −−−−−−−−−−−− −−−−−−−−−−−−−−−−−−−−−−−−− Example 3 15 ○ −−−−−−−−−−−−−−−−−−−−−−−−− −−−−−−−−−− Comparative Example 1 36 ○ −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−− Comparative Example 2 55 △ −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−− Plate surface protective agent not used 10 × −−−−−−−−−−− −−−−−−−−−−−−−−−−−−−−−−−−− * ○ Not dirty △ Slightly dirty × Extremely dirty

As described above, when water-soluble soybean hemicellulose was used, a plate surface protective agent for a lithographic printing plate excellent in both oil sensitivity in the image area and insensitivity in the non-image area could be prepared.

As described above, a plate surface protective agent for a lithographic printing plate using water-soluble hemicellulose as a water-soluble polymer can be easily applied on a plate using a sponge, cotton tampon, automatic gum coater, or the like. It is excellent in both the oil sensitivity of the part and the desensitizing property of the non-image part, and can be easily removed by washing with water or contact with a humidifying roller even after long-term storage. Further, since the hydrophilicity of the non-image portion and the lipophilicity of the image portion can be maintained, no printing loss occurs in the lithographic printing plate treated thereby.

Example 4 Solution A 5% aqueous soybean hemicellulose (a) aqueous solution 61.70 parts Sulfamic acid 3.00 parts 85% phosphoric acid 1.00 part Neugen ET-120 2.00 parts (polyethylene glycol oleyl ether, Glycerin 9.90 parts Magnesium nitrate 0.50 parts Liquid B n-heptane 19.90 parts Epan-450 2.00 parts (Block copolymer of polypropylene glycol and polyethylene glycol ether, Daiichi Kogyo) Pharmaceutical Co., Ltd.)

The solution B was dropped and dispersed in the solution A prepared as described above while stirring, and then homogenized (GAUL
(In Co., Inc.) to obtain a plate cleaning agent for a lithographic printing plate.

Example 5 A plate surface cleaner was obtained in the same manner as in Example 4 except that water-soluble soybean hemicellulose (c) was used instead of water-soluble soybean hemicellulose (a).

Comparative Example 3 A plate surface cleaner was obtained in the same manner as in Example 4 except that gum arabic was used instead of water-soluble soybean hemicellulose (a).

In order to efficiently determine the effect of each plate surface cleaning agent obtained in the above Examples and Comparative Examples, it is described in Example 1 of JP-B-51-33444, similarly to the case of the image erasing agent. A positive photosensitive lithographic printing plate obtained by the above method was prepared.

A part of the non-image area on the obtained printing plate was damaged with a needle, and oleic acid was rubbed in. When printing was performed on 100 sheets using the scratched printing plate, the scratched portions were all stained. The contaminated area was wiped off from the scratched printing plate using each plate surface cleaning agent, and printing was further performed on 60,000 sheets to confirm whether the contaminated area was completely cleaned.

The results are shown below in comparison. Number of prints with incomplete erasure of contaminated spots wiped off by the plate cleaning agent --- --- --- --- --- --- --- --- --- ---
−−−−−−− Example 4 0 −−−−−−−−−−−−−−−−−−−−−−−−−−−
−−−−−−− Example 5 0 −−−−−−−−−−−−−−−−−−−−−−−−−−−
−−−−−−− Comparative Example 3 29 −−−−−−−−−−−−−−−−−−−−−−−−−−−
−−−−−−−−

As described above, when water-soluble hemicellulose was used, a plate surface cleaning agent having excellent emulsifying properties, detergency against contamination in the hydrophilic region, and reproducibility in the hydrophilic region was obtained.

Example 6 30% aqueous soybean hemicellulose (a) aqueous solution 7.00 parts Dimethylformamide 46.00 parts Cyclohexanone 24.00 parts Methoxycellulose 2.00 parts Nonionic surfactant * 13.00 parts 85% phosphoric acid 5.00 parts Colored dye (Safranine) 0.01 parts Silicic acid fine powder 2.99 parts -------------------------------------------------------------------------- --- Polyoxyethylene-polyoxypropylene copolymer (manufactured by Asahi Denka Co., Ltd.) The above components were uniformly mixed to obtain an image erasing agent for a lithographic printing plate.

Example 7 An image erasing agent was obtained in the same manner as in Example 6, except that water-soluble soybean hemicellulose (b) was used instead of water-soluble soybean hemicellulose (a).

Example 8 An image erasing agent was obtained in the same manner as in Example 6, except that the water-soluble soybean hemicellulose (A) was used instead of the water-soluble soybean hemicellulose (A).

Comparative Example 4 An image erasing agent was obtained in the same manner as in Example 6 except that gum arabic was used instead of water-soluble soybean hemicellulose (A).

In order to efficiently determine the effect of each image erasing agent obtained in the above Examples and Comparative Examples, Japanese Patent Publication No. Sho 51-3
A positive photosensitive lithographic printing plate obtained by the method described in Example 1 of JP-A-3344 was prepared.

That is, a positive photosensitive lithographic printing plate was prepared by applying a mixture of a diazo oxide resin and a phenol resin as a photosensitive layer on a grained and anodized aluminum plate. Next, an image was formed on the printing plate by exposing the image through a mesh positive film and developing with an alkali developing solution. An appropriate amount of each of the above-described image erasing agents was applied to a part of this image with a brush and left for 2 minutes. Thereafter, the erasing agent was washed away with running water, and after draining, a gumming treatment was performed.

The printing plate was used to print 30,000 sheets.
It was checked whether the image was completely erased without receiving the printing ink for the image portion to which each image erasing agent was applied.

The results are shown below in comparison. Number of prints with incomplete image erasure for the image portion to which the image erasing agent has been applied ------------------------------------
−−−−−−− Example 6 5 −−−−−−−−−−−−−−−−−−−−−−−−−−−
Example 7 2-----------------------------------------------------
−−−−−−− Example 8 8 −−−−−−−−−−−−−−−−−−−−−−−−−−
−−−−−−− Comparative Example 4 35 −−−−−−−−−−−−−−−−−−−−−−−−−−−
−−−−−−−−

As described above, when the water-soluble hemicellulose was used, an image erasing agent having an excellent ability to prevent unwashed and excellent image erasing stability was obtained.

As described above, an image erasing agent for a lithographic printing plate using water-soluble hemicellulose as a water-soluble polymer can be easily prepared only by mixing the respective components, and is applied to an image portion to be erased. It was confirmed that the film was excellent in the effect of preventing residual washing and the erasing stability of an image and was effective.

Example 9 Pure water 98.24 parts Water-soluble soybean hemicellulose (a) 0.20 parts Magnesium nitrate 0.30 parts Phosphoric acid 0.13 parts Primary ammonium citrate 0.13 parts Isopropyl alcohol 1.00 parts −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−− The above components were prepared to obtain a fountain solution composition for lithographic printing. .

Example 10 A fountain solution composition was obtained in the same manner as in Example 9 except that water-soluble soybean hemicellulose (a) was used instead of water-soluble soybean hemicellulose (a). Was.

Example 11 A dampening solution composition was obtained in the same manner as in Example 9 except that water-soluble soybean hemicellulose (C) was used instead of water-soluble soybean hemicellulose (C). Was.

Example 12 Pure water 98.980 parts Water-soluble soybean hemicellulose (a) 0.050 parts Dibasic sodium phosphate 0.030 parts Monoammonium citrate 0.020 parts 4-isothiazolin-3-one compound 0 0.0002 parts Ethylene glycol monoisopropyl ether 0.600 parts 2-ethyl-1,3-hexanediol ethylene oxide 1-4 mol adduct 0.300 parts Silicone resin 0.018 parts ----------- The above-mentioned components were prepared to obtain a fountain solution composition for lithographic printing.

Comparative Example 5 A fountain solution composition was obtained in the same manner as in Example 9 except that gum arabic was used instead of water-soluble soybean hemicellulose (a).

Comparative Example 6 A dampening solution composition was obtained in exactly the same manner as in Comparative Example 5, except that dextrin was used instead of gum arabic.

Comparative Example 7 The procedure of Example 12 was repeated, except that gum arabic was used instead of using water-soluble soybean hemicellulose (a).
A fountain solution composition was obtained in exactly the same manner as in 12.

Each fountain solution composition obtained in the above Examples and Comparative Examples was set in an offset printing machine Heidel SORM (manufactured by Heidel Printing Co., Ltd.) (Kalcolor water supply device).

On the other hand, as a lithographic printing plate, FPS-2 (anodized multi-grain type positive PS plate, manufactured by Fuji Photo Film Co., Ltd.) was exposed, and a PS automatic developing machine 800E was used.
2. Positive developer DP-4 (Fuji Photo Film Co., Ltd.)
(Made 8 times with water), Positive Finisher FP
(Diluted 2 times with water) Developed and gummed using Fuji Photo Film Co., Ltd.
The characteristics of the dampening solution were evaluated for the following items.

A. Metering roll dirt. Investigate and evaluate the degree of ink contamination on the watering metering roll. Very small amount ○ Small amount △ Dirty ×

B. Bleedability. After printing 5000 to 10000 sheets using ink (Dai Nippon Ink Co., Ltd. Apex G Beni S), the operation of the printing press was suspended, and the degree of ink in the image area bleeding into the non-image area was investigated and evaluated. I do. No bleeding ○ Some bleeding △ Bleeding ×

C. Emulsion stability. Investigate and evaluate the emulsified state of the ink on the ink kneading roll after printing 10,000 sheets. Good ○ Somewhat bad △ Bad ×

D. Continuous stability. Using fresh water as the dampening water, determine the amount of dampening water (minimum water level) that does not cause stains when printing 10,000 sheets, and print using various dampening water with this minimum water level. Evaluation is made based on the number of printed sheets until stains on printed matter are generated. 10,000 sheets or more ○ 10,000 to 3000 sheets △ Less than 3000 sheets ×

The results are shown below in comparison. Characteristic evaluation items of dampening solution a. b. c. d. −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−− Example 9 ○ ○ ○ ○ −−−−−−−−−−− −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−− −−−−−−−−−−−−− Example 11 ○ ○ ○ ○ −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−− − Example 12 ○ ○ ○ ○ −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−− Comparative Example 5 ○ ○ △ ○ −−− −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−− Comparative Example 6 ○ ○ △ △ −−−−−−−−−−−−−−−− −−−−−−−−−−−−−−−−−−− Comparative Example 7 ○ ○ △ ○ −−−−−−−−−−−−−−−−−−−−−−−−−− −−−−−−−−

As described above, the suitability of the fountain solution composition obtained according to this example was examined. As a result, it was found that all of the soiling of the metering roll, bleeding property, emulsion stability and continuous stability were good. .

As described above, the fountain solution composition for lithographic printing obtained using the water-soluble hemicellulose can be easily prepared as a concentrated solution simply by mixing the respective components. It can be used simply by diluting with. Furthermore, these were excellent in the properties as a dampening solution composition, such as stain resistance of metering rolls, bleeding property, emulsion stability and continuous stability.

[0127]

As described above, the lithographic printing plate surface protective agent obtained by using water-soluble hemicellulose as a lithographic printing plate aid can be easily applied onto a plate using a sponge, a cotton tampon, an automatic gum coater or the like. It is excellent in both the oil sensitivity of the image area and the desensitizing property of the non-image area. Even if stored for a long time, it can be easily removed by washing with water or contact with a humidifying roller. it can. Further, since the hydrophilicity of the non-image portion and the lipophilicity of the image portion can be maintained, no printing loss occurs in the lithographic printing plate treated thereby.

The lithographic printing plate image erasing agent obtained by using water-soluble hemicellulose as a lithographic printing plate aid can be easily prepared only by mixing the respective components, and is used for the image portion to be erased. When applied, it has an excellent effect of preventing unwashing and an image erasing stability. Further, the fountain solution composition for lithographic printing obtained using the water-soluble hemicellulose is excellent as a fountain solution composition such as a stain-proofing property for metering rolls, bleeding property, emulsion stability, and continuous stability. It has an effect.

As described above, the printing aid containing water-soluble hemicellulose as an active ingredient has a film-forming property, a long-term storage property, an emulsifying property and a non-image area even when compared with known water-soluble polymers. It has excellent desensitizing properties.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B41N 3/00-3/08 G03F 7/40

Claims (5)

(57) [Claims] 1. A printing aid comprising water-soluble soybean-derived hemicellulose as an active ingredient. 2. The printing auxiliary according to claim 1, wherein the auxiliary is a plate surface protective agent for a lithographic printing plate. 3. The printing auxiliary according to claim 1, wherein the auxiliary is a plate cleaning agent for a lithographic printing plate. 4. The printing auxiliary according to claim 1, wherein the auxiliary is an image erasing agent for a lithographic printing plate. 5. The printing auxiliary according to claim 1, wherein the auxiliary is a fountain solution composition for lithographic printing.