JP2000289367A - Covering agent composition for ink roller of printing machine and protective method for ink roller using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the covering agent composition for an ink roller, with which a printing can be re-worked with almost no adjustment even after the interruption of the printing and which is environment-friendly, and the protective method for the ink roller, in which the composition is used. SOLUTION: This covering agent composition includes a binder resin for a lithographic ink and a kind of vegetable oils selected from the group consisting of semidrying oils and nondryhing oils. In this case, the above vegetable oil is set to occupy 5-80 wt.% of the whole covering agent composition. As the result, the change of viscosity of the roller is also small and the drying property of the composition can be retarded.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coating composition for an ink roller for coating an ink roller of a lithographic printing press to prevent the diameter from being reduced due to the release of a solvent from the roller and the like. The ink roller protection method.

[0002]

2. Description of the Related Art As shown in FIG. 1, a lithographic printing press generally has a rubber roller called an ink roller, such as an ink supply roller 2, an ink transfer roller 3, ink kneading rollers 4, 5 and an ink application roller 7. And a metal ink mixing roller 6. The printing ink supplied from the ink fountain 1 is transferred between the above-mentioned plurality of rollers, and is carried to the plate cylinder 8 to be a blanket cylinder (not shown).
Is transferred to a printing material such as paper through the substrate to obtain a printed material.

[0003] The lithographic printing method is a typical printing method which has good image reproducibility and can obtain a cosmetic print.
High precision is also required for adjustment of each part of the printing press used. For example, ink is supplied to the printing plate by pressing contact between the rotating ink roller and the plate cylinder, but if the pressing force is too low, the ink supply amount becomes insufficient immediately and the density becomes insufficient, and the printed matter becomes poor. It may cause rash and omission.

For this reason, it is necessary to sufficiently perform an initial adjustment of the ink supply amount before starting the actual printing, and this adjustment is a major cause of lowering the work efficiency.

Further, the solvent used in the printing ink composition has the property of swelling the ink roller. As the printing operation proceeds, as the roller temperature increases, the amount of swelling due to the solvent increases and the diameter of the ink roller increases.
Therefore, it is necessary to finely adjust the pressing force until the diameter does not change even after the start of the main printing.

[0006] When printing of the same printed material is performed for many days, if the first printing is completed and the printing is interrupted until the next day, the original temperature is lowered due to the temperature drop of the ink roller and the solvent is removed. As a result, the roller nip (the contact area between the rollers) becomes narrower than before the printing press stopped, and when the printing press was restarted, the proper ink transfer was not performed and various troubles occurred. appear.

Therefore, even if the initial adjustment and the fine adjustment are completed, the same work is required every time printing is interrupted thereafter, and this adjustment time affects the printing cost, which is a problem.

In order to solve this problem, a method of keeping a printing machine covered with a plastic sheet cover to keep it warm, and a method of applying machine oil to an ink roller before interruption have been tried. However, there is little effect. Is the current situation.

In order to solve these problems, the present applicant has already disclosed in JP-A-10-250256 a coating composition for an ink roller containing an ink binder resin, a high-boiling mineral oil and a drying inhibitor. Has been proposed.

[0010] The coating composition for an ink roller proposed by the present applicant is effective in solving the above problems. However, when higher performance is required, this coating composition for an ink roller is still insufficient as an ink roller protective agent because it has problems such as drying properties on a roller and a change in viscosity.

Further, in recent years, environmental issues have been regarded as important, and a coating composition for an ink roller has been demanded in response thereto.

[0012]

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned problems, and to provide an environment-friendly ink roller in which printing can be resumed with little adjustment even after printing has been interrupted. And a method for protecting an ink roller using the same.

[0013]

That is, the present invention provides:
(1) A coating composition for an ink roller comprising a binder resin for a lithographic ink and at least one vegetable oil selected from a semi-drying oil and a non-drying oil, wherein the vegetable oil is contained in a total coating composition. The present invention relates to a coating composition for an ink roller characterized by containing from 5 to 80% by weight.

Further, the present invention relates to (2) the coating composition for an ink roller according to the above (1), further comprising an inorganic pigment and / or an organic pigment.

Further, the present invention provides (3) an ink roller comprising applying the coating composition for an ink roller according to any of the above (1) or (2) to an ink roller of a lithographic printing press. Regarding protection methods.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.

As the binder resin of the coating composition for an ink roller of the present invention, a binder resin for a lithographic ink is used.
This is because the composition of the coating composition for an ink roller of the present invention is made as close as possible to the composition of the lithographic ink, and even if it is mixed with the lithographic ink to be used, the influence on the printed matter is reduced.

The lithographic ink binder resin used in the present invention includes petroleum resin, phenolic resin, rosin-modified phenolic resin, various alkyd resins, rosin-maleic acid resin, polyester resin, cyclized rubber and the like, or modified products thereof. can give. These binder resins can be used alone or in combination of two or more.

The binder resin for lithographic ink is usually contained in the entire ink roller coating composition in an amount of 5 to 40% by weight, preferably 15 to 40% by weight.

The at least one vegetable oil selected from the semi-drying oil and the non-drying oil used in the present invention includes soybean oil, rapeseed oil, cottonseed oil, olive oil, castor oil and the like. These vegetable oils can be used alone or
Two or more can be used in combination. Vegetable oil is usually 5 to 80% by weight, preferably 35 to 80% by weight in the coating composition for all ink rollers.
60% by weight is contained.

When the content of the vegetable oil is less than the above range,
The effect of preventing diameter reduction of the ink roller and the effect of preventing the coating composition for ink roller from being tacked up (rapid increase in viscosity) on the roller are not exhibited. On the other hand, when the content of the vegetable oil exceeds the above range, the viscosity of the coating composition for an ink roller becomes low, and it becomes difficult to coat the roller composition.

The coating composition for an ink roller of the present invention may optionally contain a mineral oil as long as the performance is not reduced. Among them, the boiling point temperature is 350 ° C. to 490 ° C.
Mineral oil can be suitably used.

As the mineral oil having a boiling point range of 350 ° C. to 490 ° C., a high boiling point petroleum fraction generally called machine oil can be used. For example, Sankyo Ink Oil 145 manufactured by Sankyo Yuka Kogyo Co., Ltd. (boiling point range of 398 ° C. to 488) C), Nippon Oil Co., Ltd. Nisseki Ink Oil 20 (boiling point range 352 ° C to 4 ° C)
85 ° C.).

When a mineral oil having a boiling point range lower than the above range is used, it is tacked up on a roller, and as described later, when the coating composition is removed by using a printing material such as paper at the start of reprinting, Problems such as paper wrapping and the like tend to occur. In addition, when a mineral oil having a boiling point range higher than the above range is used, the viscosity of the coating composition itself becomes high, and there is a problem that it takes too much time to remove this at the start of reprinting.

In the present invention, if necessary, an inorganic pigment and / or an organic pigment can be blended.

Examples of the inorganic pigments include calcium carbonate, precipitated barium sulfate, white carbon, silica, alumina white, aluminum hydroxide, kaolin, clay, talc, bentonite and the like; white pigments such as titanium oxide and zinc white; Colored pigments such as black, iron black, red iron, navy blue and the like can be mentioned.

Organic pigments such as insoluble azo pigments, azo lake pigments, condensed azo pigments, phthalocyanine pigments, quinacridone pigments, isoindolinone pigments, isoindoline pigments, and dioxazine pigments are generally used in lithographic inks. Available pigments are available.

When these pigments are used, they can be incorporated in the coating composition for all ink rollers at a ratio of 5 to 50% by weight, preferably 5 to 35% by weight. When a pigment is blended, it is preferable that the color be similar to the color of the printing ink to be used, so that even if it is mixed with the printing ink, the influence on the printed matter can be reduced.

In the present invention, if necessary, a drying inhibitor can be used in combination in the coating composition for an ink roller.

As drying inhibitors, phenolic antioxidants such as 2,6-di-tert-butyl-3-methylphenol (BHT), styrenated phenol, and n-octadecyl-3- (3,5- Examples thereof include (di-t-butyl-4-hydroxyphenyl) propionate, eugenol, pyrogallol, catechol, and guaiacol, and quinone-based compounds include 2-t-butylhydroquinone and hydroquinone; and amine-based compounds include alkylated diphenylamine. When a drying inhibitor is used, it is preferred that the content be 1% by weight or less in the coating composition for all ink rollers.

Among the coating compositions for ink rollers of the present invention, preferred compositions are binder resins 15 to 4 for ink.
0% by weight, 35 to 60% by weight of vegetable oil, 5 to 50% by weight of pigment, containing no mineral oil or containing 1 to 10% by weight of a mineral oil having a boiling range of 350 to 490 ° C when containing a mineral oil. , Further containing no drying inhibitor, or 1
% By weight or less.

One embodiment of the ink roller protecting method of the present invention will be described with reference to FIG. FIG. 1 is a schematic diagram of an ink supply unit of a lithographic printing apparatus. When printing is stopped, the pressure between the ink discharge roller 2 and the ink transfer roller 3 is released to bring the ink transfer roller 3 into a non-contact state, and the ink transfer roller 3 is coated with the ink roller coating composition with a spatula or the like. 5, 6, transfer to each roller while rotating the ink applying roller 7 at a low speed to coat.
In addition, a supply device 9 for a coating composition for an ink roller is installed on the ink transfer roller 3, and each of the rollers 4, 5, 6,
Another preferred embodiment is to coat the ink roller coating composition while transferring the coating composition to No. 7. The coating amount of the coating composition for an ink roller is not particularly limited, but is usually preferably in the range of 5 to 30 g / m ² .

Next, by performing a normal printing operation using a printing material such as paper at the time of resuming printing, a coating composition for an ink roller on an ink roller through a blanket together with a newly supplied printing ink. Transfer and remove. Since the coating composition for an ink roller of the present invention has a small tack-up, it can be easily removed from the ink roller in a short time without trouble such as wrapping of paper, and since the composition is close to the printing ink composition, it can be printed. Even if mixed into the ink, it has little effect on the printed matter, and a good printed matter can be obtained immediately without special removal work.

With the protection method of the present invention, the diameter of the ink roller is prevented from being reduced when the printing press is stopped, the change in the roller nip of each ink roller is small, and the tack-up of the coating composition for the ink roller is small. There is no need to readjust the pressure between the ink rollers at the time of restart, and if the ink supply roller 2 and the ink transfer roller 3 are brought into contact with each other and ink is supplied from the ink fountain 1, reprinting can be performed in a short time. Can be greatly reduced.

[0035]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples. In the examples, parts and% represent parts by weight and% by weight, respectively.

<Varnish Production Example> [Varnish A] In a four-necked flask equipped with a stirrer, a condenser and a thermometer, 40 parts of Tamanol 361 (rosin-modified phenol resin, manufactured by Arakawa Chemical Industries, Ltd.), No. 6 solvent ( 40 parts of mineral oil having a boiling point range of 294 ° C. to 345 ° C., manufactured by Nippon Petrochemical Co., Ltd., hereinafter referred to as “mineral oil A”, and 20 parts of polymerized linseed oil were charged. After stirring for 100 minutes, 100 parts of Varnish A was obtained.

[Varnish B] In a four-necked flask equipped with a stirrer, a condenser and a thermometer, 40 parts of Tamanol 361 (rosin-modified phenol resin, manufactured by Arakawa Chemical Industries, Ltd.)
No. 6 solvent (40 parts) and soybean oil (20 parts) were charged, and the mixture was heated and heated while blowing nitrogen gas, and stirred at 200 ° C. for 30 minutes to obtain 100 parts of varnish B.

[Varnish C] Forty parts of Tamanol 361 were placed in a four-necked flask equipped with a stirrer, a condenser and a thermometer.
60 parts of soybean oil was charged, the temperature was increased while blowing nitrogen gas, and the mixture was stirred at 200 ° C. for 30 minutes to obtain 100 parts of varnish C.

Example 1 Varnish A 25 parts, Varnish B3
0 parts, white gloss flower CC (calcium carbonate, Shiroishi Industry Co., Ltd.)
30 parts) and 7.5 parts of mineral oil A were preliminarily mixed and then ground with a three-roll mill. Next, Sankyo Ink Oil 145
(Boiling range 398 ° C to 488 ° C, Sankyo Yuka Kogyo Co., Ltd.)
(Hereinafter referred to as mineral oil B) 7 parts and BHT (drying inhibitor)
0.5 parts was added, and the mixture was continuously mixed with three rolls to obtain a coating composition 1 for an ink roller.

[Example 2] Varnish B 55 parts, white gloss flower CC
After preliminarily mixing 30 parts and 7.5 parts of mineral oil A, the mixture was kneaded with three rolls. Next, 7 parts of mineral oil B and 0.5 parts of BHT
Then, the mixture was added, and the mixture was continuously mixed with three rolls to obtain a coating composition 2 for an ink roller.

Example 3 55 parts of varnish C, white glossy flower CC
After preliminarily mixing 30 parts and 15 parts of mineral oil A, the mixture was kneaded with three rolls to obtain a coating composition 3 for an ink roller.

Example 4 In Example 3, mineral oil A
Was prepared in the same manner except that 7 parts were replaced with mineral oil B to obtain a coating composition 4 for an ink roller.

Example 5 In Example 3, mineral oil A
Adjusted in the same way except that 7 parts of was replaced with soybean oil,
Ink roller coating composition 5 was obtained.

Example 6 55 parts of varnish C, white glossy flower CC
After 30 parts of soybean oil and 8 parts of soybean oil were preliminarily mixed, the mixture was ground with three rolls. Next, 6.5 parts of mineral oil A and 0.5 part of BHT were added, and the mixture was continuously milled with three rolls to obtain a coating composition 6 for an ink roller.

Example 7 In Example 3, mineral oil A
Was replaced with soybean oil, and mineral oil A was replaced with 8 parts of mineral oil B, to prepare a coating composition 7 for ink roller.

Example 8 In Example 3, mineral oil A
Was replaced with soybean oil in the same manner to obtain a coating composition 8 for ink rollers.

[Example 9] In Example 3, the mineral oil A
Was prepared in the same manner except that rapeseed oil was used instead of 15 parts to obtain a coating composition 9 for an ink roller.

Example 10 Varnish B 15 parts, Varnish C
After premixing 80 parts and 5 parts of soybean oil, the mixture was adjusted with three rolls to obtain a coating composition 10 for an ink roller.

Comparative Example 1 Varnish A 55 parts, white gloss flower CC
After 30 parts of linseed oil and 15 parts of linseed oil were preliminarily mixed, the mixture was kneaded with three rolls to obtain a coating composition 11 for an ink roller.

Comparative Example 2 Varnish A 40 parts, Varnish B1
After preliminarily mixing 5 parts, 30 parts of white glossy flower CC and 7.5 parts of mineral oil A, the mixture was ground with a three-roll mill. Next, mineral oil B7
And 0.5 part of BHT were added, and the mixture was continuously milled with three rolls to obtain a coating composition 12 for an ink roller.

Comparative Example 3 55 parts of varnish A, white glossy flower CC
After preliminarily mixing 30 parts and 7 parts of mineral oil A, the mixture was ground with three rolls. Next, 7 parts of mineral oil B and 1 part of BHT were added, and the mixture was continuously milled with three rolls to obtain a coating composition 13 for an ink roller.

[Comparative Example 4] Varnish A 53 parts, white glossy flower CC
After premixing 23 parts and 7 parts of mineral oil A, the mixture was kneaded with three rolls. Subsequently, 7 parts of mineral oil B and 10 parts of BHT were added, and the mixture was continuously milled with three rolls to obtain a coating composition 14 for an ink roller.

Table 1 shows the compositions of the coating compositions 1 to 14 for the ink roller. Table 2 shows the content of each oil component in the coating composition for all ink rollers.

[Evaluation Method and Results] (1) Change in Roller Nip After printing with a lithographic printing machine, printing was interrupted, and the coating composition for ink roller 1 to 14 was applied to the ink roller at an amount of 5 g / m ^2. And left standing at room temperature for 10 days to confirm the state.

Evaluation ：: A state in which there is almost no reduction in the roller diameter and there is no need to adjust the pressure. ×: The roller diameter is thin and needs to be adjusted.

(2) Change in Viscosity on Roller Coating compositions 1 to 14 for ink rollers were applied on a rotating roller of an incometer.
Evaluation was performed by finger for 10 hours every hour.

[0057]

(3) Drying property Coating compositions 1 to 14 for ink rollers were coated on a glass plate using a 3-mils coating rod, and the drying property of each coating film at 35 ° C. was evaluated.

[0059] Table 1 shows the test results.

[0060]

[Table 1]

[0061]

[Table 2]

[0062]

The coating composition for an ink roller of the present invention is more environmentally friendly than the conventional one. By applying the coating composition to an ink roller when printing is interrupted in a lithographic printing machine, the roller diameter can be reduced at the start of reprinting. Thinning,
Although it took a lot of time to readjust the roller nip, reprinting can be started in a short time, and the working time can be greatly reduced. In addition, the coating composition for an ink roller of the present invention can reduce the change in viscosity on the roller and can also reduce the drying property as compared with the conventional coating composition for an ink roller. Furthermore, since the coating composition for an ink roller of the present invention is a composition close to a printing ink, even if mixed into the printing ink, the influence on the printed matter is small, and a good printed matter can be obtained immediately without special removal work. .

[Brief description of the drawings]

FIG. 1 is a schematic diagram illustrating an ink supply unit of a lithographic printing apparatus.

[Description of Signs] 1 Ink fountain 2 Ink ejection roller 3 Ink transfer roller 4, 5 Ink kneading roller 6 Ink kneading roller 7 Ink applying roller 8 Plate cylinder 9 Coating agent supply device

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Koji Miyao 1-23-23 Edobori, Nishi-ku, Osaka-shi F-term in Sakata Inks Co., Ltd. (reference) 2C250 DC12

Claims (3)

[Claims] A coating composition for an ink roller, comprising a binder resin for a lithographic ink and at least one vegetable oil selected from a semi-dry oil and a non-dry oil,
A coating composition for an ink roller, comprising 5 to 80% by weight of the vegetable oil in the total coating composition. 2. The coating composition for an ink roller according to claim 1, further comprising an inorganic pigment and / or an organic pigment. 3. The ink roller of a lithographic printing press according to claim 1.
Or a method for protecting an ink roller, comprising applying the coating composition for an ink roller according to 2 above.