JPH10279872A - Lithographic printing ink - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a dampening-water-free lithographic printing ink having improved printability and excellent printing effect by using an aliphatic hydrocarbon resin having a specified softening point and extracted from gilsonite as a component of the vehicle resin. SOLUTION: This ink contains an aliphatic hydrocarbon resin having a softening point of 120-125 deg.C and extracted from gilsonite, a synthetic resin and a petroleum-derived solvent having an aromatic hydrocarbon content of 1 wt.% or below. Desirably, the ink has a composition: 0.5-20 wt.% aliphatic hydrocarbon resin extracted from gilsonite, 5-40 wt.% synthetic resin and 25-50 wt.% petroleum-derived solvent. The synthetic resin used in combination with the gilsonite resin is exemplified by a rosin-modified phenolic resin, a petroleum resin, an alkyd resin, a rosin-modified alkyd resin or a rosin ester and is desirably a rosin-modified phenolic resin.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for obtaining excellent carbon black wettability by using an aliphatic hydrocarbon resin having a softening point of 120 ° C. to 125 ° C. extracted from Gilsonite as one component of a vehicle resin. High performance inks such as drastic improvement in flowability, low tack, excellent tack stability, and printability improvement such as background stain resistance and transfer between rollers. The present invention relates to a lithographic printing ink excellent in printing effects such as gloss, gloss and dot reproducibility.

[0002]

2. Description of the Related Art In lithographic printing, which is the mainstream of current printing, a dampening solution is supplied to a non-image area, and an image is formed by utilizing ink repulsion. In recent years, a lithographic printing method without water has been proposed as a method for solving the problem relating to the dampening solution. In particular, a silicone rubber is provided in a non-image area for the purpose of showing ink repellency in place of the dampening solution. Printing methods have been put to practical use.

[0003] In such waterless lithographic printing, it has been known that when printing is performed using a conventional oil-based ink, sufficient ink repulsion in a non-image area cannot be obtained, and background stains are generated, which is not preferable. I have. The phenomenon of background contamination in waterless printing is caused by the temperature rise caused by the friction of the drive unit and rollers of the printing press during printing and the fact that the plate cooling effect due to the evaporation of water is lost because no dampening water is used. As the temperature rises, the cohesive force of the ink itself decreases,
The ink adheres to the non-image area where ink should be repelled.

In order to solve the problems peculiar to waterless printing, the binder resin component is increased in molecular weight to increase cohesion, a silicone oil is added, and a silicone-modified resin is used. Although the resistance is improved, the so-called printability, such as the transferability of the ink between rollers during printing and the stability on a printing press, is deteriorated, and it is sometimes difficult to obtain a good printed matter.

[0005] Waterless lithographic printing inks using carbon black have poor wettability and poor flowability of the carbon black, so that the ink is too tight over time, and has problems with the inking property and gloss, which is preferable. Absent.

On the other hand, among various solvents that have been widely used in the past, aromatic components such as benzene, toluene and xylene are irritating to the human body as regulated by the Industrial Safety and Health Law. Strict regulations are imposed to cause sexual and neurological disorders. Also recently ILO
Just as the (International Labor Organization) has chosen a treaty to protect the safety of workers handling chemicals, there is a growing international momentum to protect humans from the harm of chemicals. The conventional solvent for printing ink contains 15 to 15 aromatic components in addition to the aromatic component in addition to the paraffinic and naphthenic components.
It contained 20% by weight, which caused problems such as odor and contamination of the working environment.

[0007] In order to alleviate such a problem as much as possible, among solvents for printing inks, a solvent containing no aromatic component is used, compared with a conventional 100% normal paraffinic solvent or a recently developed naphthenic component. A method of using such a solvent in combination with a conventional solvent has been adopted. Even in that case, the problem of contamination of the working environment was not solved, and the printing suitability and printing effect as a waterless lithographic printing ink were also insufficient.

[0008]

SUMMARY OF THE INVENTION The present invention provides an excellent high-performance ink by using an aliphatic hydrocarbon resin having a softening point of 120 ° C. to 125 ° C. extracted from Gilsonite as one component of a vehicle resin. In addition, the printability can be improved, and an excellent printing effect can be obtained.

[0009]

[Means for Solving the Problems]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention relates to an aliphatic hydrocarbon resin having a softening point of 120 ° C. to 125 ° C. extracted from Gilsonite, a synthetic resin and an aromatic hydrocarbon content of 1% by weight. The present invention relates to a lithographic printing ink comprising the following petroleum solvent.

The aliphatic hydrocarbon resin having a softening point of 120 ° C. to 125 ° C. extracted from Gilsonite used in the present invention is Gilsonite, a resin extracted from natural asphaltum. The aliphatic hydrocarbon resin having a softening point of 120 ° C. to 125 ° C. extracted from the Gilsonite of the present invention does not contain aromatic hydrocarbons, ash, and light fractions in Gilsonite, and has excellent carbon black wettability. It has the property of instability of viscosity, which is a problem with Gilsonite, clogging at the time of filtration due to agglomerates, odor and other problems are solved,
In addition, it has excellent solubility in Aliphatic ink solvents and vegetable oils, and it is in the form of flakes without worrying about dust,
Excellent safety with no adverse effects on the human body.

The synthetic resin used in the lithographic printing ink together with the Gilsonite resin used in the present invention includes:
A rosin-modified phenol resin, a petroleum resin, an alkyd resin, a rosin-modified alkyd resin, and a rosin ester are considered, and a rosin-modified phenol resin is preferable.

The rosin-modified phenolic resin of the present invention has a weight average molecular weight (hereinafter simply referred to as molecular weight) of 80,000 to 50.
10,000, preferably 80,000 to 300,000, and the cloudiness point (shown in the following formula) for normal tetradecane is 20 to
70%, preferably 30 to 50%. If the molecular weight is less than 80,000, the varnish will have insufficient cohesive force, and thus will not have sufficient background stain resistance as an ink, and will have a molecular weight of 50.
If it exceeds 10,000, the fluidity of the ink becomes insufficient and the transferability of the ink on a printing press is poor, which is not preferable. On the other hand, when the cloudiness point is less than 20%, the solubility of the resin is too good, and the setting property of the ink is poor, which is not preferable.
Further, when the cloudiness point exceeds 70%, not only is the pigment dispersibility of the varnish insufficient, but also the fluidity, gloss and inking property of the ink are unfavorable. Cloud point (%) = resin (2 g) / [resin (2 g) + solvent (Xg)] × 100 (where X is a solution obtained by adding normal tetradecane to 2 g of resin, dissolving by heating, and then cooling to 25 ° C.) Is the minimum value of normal tetradecane that becomes cloudy.

The rosin-modified phenolic resin may be of any type and composition such as rosins, phenols, polyhydric alcohols, and other dibasic acids as a modifier. That is, as rosins, gum rosin, wood rosin, polymerized rosin, tall oil rosin, disproportionated rosin, and the like, and phenols such as butyl phenol, aluminum phenol, octyl phenol, nonyl phenol, dodecyl phenol, and the like,
Polyhydric alcohols include glycerin, pentaerythritol, trimethylolpropane, diethylene glycol, and the like. Dibasic acids include phthalic acid, adipic acid, and maleic acid.

Known methods can be used for producing the rosin-modified phenolic resin, such as a method in which a rosin is reacted with a resole-type phenolic resin and then esterified with a polyhydric alcohol, or the rosin is converted into a polyhydric alcohol. And then reacting with a resole-type phenol resin after esterification. The ink solvent used in the present invention has an aromatic hydrocarbon content of 1% by weight or less and an aniline point of 75 to 95 ° C, preferably 80 to 95 ° C.
° C and a boiling point of 260-350 ° C, preferably 280-35.
It is a petroleum solvent in the range of 0 ° C. Aniline point is 75
If the temperature is lower than ℃, the ability to dissolve the resin is too high,
Ink setting property is remarkably inferior and not preferable.
When the temperature exceeds ℃, the dissolving power of the resin is poor, so that the fluidity of the ink is inferior, and as a result, only a printed matter having poor gloss and poor adhesion cannot be obtained. If the boiling point is lower than 260 ° C., the evaporation of the solvent in the ink on the printing press increases, and the flowability of the ink deteriorates, so that the ink is easily deposited on the blanket.
When the temperature exceeds 0 ° C., the drying property of the heat-set type ink is inferior, so that it is not preferable.

The ink solvent according to the present invention is contained in the ink in an amount of 25 to 50% by weight, preferably 30 to 45% by weight, and a petroleum solvent containing 1% by weight or more of another aromatic hydrocarbon. It is preferable not to use them in the ink. If the content of the ink solvent of the present invention is less than 25% by weight, the fluidity of the ink is insufficient, which is not preferable. If it exceeds 50% by weight, the viscosity of the ink becomes too low, and the background stain resistance becomes insufficient. Absent. Naturally, when other petroleum solvents containing aromatic hydrocarbons are used in combination, the effects of improving the odor and working environment are not sufficient, which is not preferable.

Examples of the ink solvent used in the present invention include AF Solvents 5, 6, and 7 manufactured by Nippon Oil Co., Ltd. The waterless lithographic printing ink of the present invention is produced by a conventional method using a varnish obtained by dissolving the rosin-modified phenol resin in the petroleum solvent. The varnish used in the present invention can be produced by a conventionally known method, and includes a resin, a drying oil (linseed oil, thermally polymerized linseed oil, air-blown polymerized oil, etc.), a solvent for ink, and, if necessary, aluminum stearate. Together with a gelling agent such as an aluminum chelate compound at 180 to 200 ° C. to cause a reaction.

[0017]

Now, the present invention will be described in further detail with reference to specific examples. Hereinafter, “part” indicates “part by weight” and “%” indicates “% by weight”.

Production Example of Phenol Resin In a four-necked flask equipped with a stirrer, a reflux condenser equipped with a water separator and a thermometer, 1000 parts of P-nonylphenol, 850 parts of 35% formalin, 60 parts of 93% sodium hydroxide 60 parts tap water 5
After adding 00 parts and heating to 90 ° C. and reacting for 6 hours,
1000 parts of toluene was added to dissolve the phenolic resin in toluene, 125 parts of 6N hydrochloric acid and a hydrochloric acid solution of 1000 parts of tap water were added, and the mixture was stirred and allowed to stand. The supernatant layer having a pH of 5 to 6 was taken out and washed with water. Then, 2000 parts of a toluene solution of a resol type phenol resin having a nonvolatile content of 49% was obtained, and this was used as a resol solution.

Production Example 1 of Rosin-Modified Phenol Resin 1000 parts of gum rosin was charged into a four-necked flask equipped with a stirrer, a Liebig condenser and a thermometer, and dissolved and stirred at 200 ° C. while blowing nitrogen gas.
0 parts was added and the mixture was heated at 230 ° C.
After reacting for ~ 4 hours, 110 parts of glycerin was charged,
The reaction was performed at 260 ° C. for 8 hours to obtain a resin A having an acid value of 20 or less and a molecular weight of 86,000 and a cloudiness point of 35%.

Rosin-Modified Phenol Resin Preparation Example 2 The procedure of Preparation Example 1 was repeated except that the resol solution was changed to 2900 parts to obtain a rosin-modified phenol resin having a molecular weight of 350,000.
Resin B having a cloudiness point of 60% was obtained.

Varnish Production Example 1 Resins A and B obtained in the rosin-modified phenol resin production example, linseed oil and a solvent were blended as shown in Table 1 and heated and stirred at 190 ° C. for 1 hour to prepare varnishes 1-2 and 4-8. Obtained.

[0022]

[Table 1]

Note) The numbers in the table indicate%. AF Solvent 7: Nippon Oil Corp. solvent, aniline point 83.5 ° C., boiling point 260-281 ° C., aromatic component content 0.3% No. 7 Solvent: Nippon Oil Corp., solvent aniline point 6
9.8 ° C, boiling point 255-283 ° C, aromatic component content 1
7.2% ER-125RESIN: Resin manufactured by American Gilsonite Co., Ltd. ALCH: Gelling agent manufactured by Kawaken Fine Chemical Co., Ltd.

Varnish Production Example 2 An aliphatic hydrocarbon resin having a softening point of 120.degree. C. to 125.degree. C. (hereinafter referred to as ER-125RESIN) extracted from Gilsonite is further blended with the material in the production process of Varnish 1 for 190.
Heating and stirring at 1 ° C. for 1 hour gave Varnish 3.

Inks were prepared according to the formula shown in Table 2 using three rolls according to a conventional method so that the tack value was 6 to 9, and Examples 1 to 7 and Comparative Examples 1 to 3 were prepared.

[0026]

[Table 2]

Note) The numbers in the table indicate%. Printing Test Evaluation The inks of the examples were subjected to waterless printing at 13,000 rpm using a TAP plate manufactured by Toray Industries Co., Ltd. with a printing machine Lithrone 26 manufactured by Komori Corporation.
Table 3 shows the results of evaluation of gloss and odor.

[0028]

[Table 3]

[0029] Gloss value Gloss meter GM-26D manufactured by Murakami Color Research Laboratory (60 °
-60 °)

Examples 1 to 7 according to the present invention are excellent in inking property and gloss. On the other hand, it can be seen that Comparative Examples 1 to 3 are unsatisfactory in the inking property and gloss. Further, Comparative Examples 2 and 3 had a strong odor.

As described above, the waterless lithographic printing ink obtained by the method of the present invention is excellent in background soil temperature, inking property, gloss and odor, and is sufficient as a waterless lithographic printing ink. It provides excellent printability and printing effect.

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[Procedure amendment]

[Submission date] April 30, 1997

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0030

[Correction method] Change

[Correction contents]

Examples 1 to 4 according to the present invention are excellent in inking property and gloss. On the other hand, it can be seen that Comparative Examples 1 and 2 are insufficient in the inking property and gloss. Further, Comparative Examples 1 and 2 had a strong odor.

Claims (3)

[Claims] 1. Softening point 12 extracted from Gilsonite
A lithographic printing ink comprising an aliphatic hydrocarbon resin at 0 ° C. to 125 ° C., a synthetic resin, and a petroleum solvent having an aromatic hydrocarbon content of 1% by weight or less. 2. Softening point 12 extracted from Gilsonite
When the aliphatic hydrocarbon resin at 0 ° C to 125 ° C is 0.5 to 20
% By weight, 5-40% by weight of synthetic resin, 25% of petroleum solvent
The lithographic printing ink according to claim 1, wherein the amount is from 50 to 50% by weight. 3. The lithographic printing ink according to claim 1, wherein the synthetic resin is a rosin-modified phenol resin.