JP3964071B2 - Coating composition for ink roller of printing press and method of protecting ink roller using the same - Google Patents

Description

【００６１】
【表２】

【００６２】
【発明の効果】
本発明のインキローラー用被覆剤組成物は従来のものに比べ環境にやさしく、これを平版印刷機の印刷中断時にインキローラーに塗布することによって、これまで再印刷開始時にローラー径の細りが生じ、ローラーニップの再調整に多大な時間を要していたものが、短時間で再印刷が開始でき、作業時間が大幅に短縮できる。また、本発明のインキローラー用被覆剤組成物は、従来のインキローラー用被覆剤組成物に比べて、ローラー上の粘度変化も少なく、また乾燥性も遅くすることができる。さらに、本発明のインキローラー用被覆組成物は印刷インキに近い組成であることから、印刷インキに混入しても印刷物への影響が少なく、特別な除去作業なしで良好な印刷物がすぐに得られる。
【図面の簡単な説明】
【図１】平版印刷装置のインキ供給部を示す模式図である。
【符号の説明】
１ インキ壷
２ インキ出しローラー
３ インキ移しローラー
４、５ インキ練りローラー
６ インキ練りローラー
７ インキ着けローラー
８ 版胴
９ 被覆剤供給装置[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a coating composition for an ink roller for coating an ink roller of a lithographic printing machine to prevent diameter thinning caused by detachment of a solvent from the roller, and an ink roller protection method using the same.
[0002]
[Prior art]
In general, as shown in FIG. 1, a lithographic printing machine has a rubber roller called an ink roller such as an ink discharge roller 2, an ink transfer roller 3, an ink kneading roller 4, 5 and an ink form roller 7, and a metal roller. An ink kneading roller 6 is provided. The printing ink supplied from the ink fountain 1 is transferred between the above-mentioned many rollers, is transferred to the plate cylinder 8, and is transferred to a printing material such as paper via a blanket cylinder (not shown), whereby a printed material is obtained. .
[0003]
The lithographic printing method is a typical printing method with good image reproducibility and capable of obtaining a cosmetic print, but high accuracy is required for adjustment of each part of the printing press used accordingly. For example, the ink is supplied to the printing plate by the pressing contact between the rotating ink roller and the plate cylinder. However, if the pressing force is too low, the ink supply amount is insufficient and the density is insufficient. It may cause scumming or missing.
[0004]
For this reason, the ink supply amount must be sufficiently adjusted before the actual printing is started, and this adjustment is a major cause of reducing the work efficiency.
[0005]
Furthermore, the solvent used in the printing ink composition has the property of causing the ink roller to swell. When the roller temperature increases as the printing operation proceeds, 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]
Here, when printing of the same printed matter takes many days, when the first printing is finished and the printing is interrupted until the next day, the original diameter is reduced due to the temperature drop of the ink roller or the removal of the solvent during that time. As a result, the roller nip (the contact area between the rollers) becomes narrower than before the stop of the printing press, and proper ink transfer is not performed when the printing press is restarted, and various troubles occur.
[0007]
Therefore, even if the initial adjustment and fine adjustment are completed, the same operation is required every time printing is interrupted, and this adjustment time is problematic because it affects the printing cost.
[0008]
In order to solve this problem, attempts have been made to cover the printing press with a plastic sheet cover to keep the temperature warm, and to apply machine oil to the ink roller before interruption, but it is currently ineffective. is there.
[0009]
In order to solve these problems, the present applicants have already proposed a coating composition for an ink roller containing an ink binder resin, a high-boiling-point mineral oil, and a drying inhibitor in JP-A-10-250256. ing.
[0010]
The ink roller coating composition proposed by the present applicant is effective in solving the above-mentioned problems. However, this coating composition for an ink roller is still insufficient as an ink roller protective agent because it has problems such as drying on the roller and viscosity change when higher performance is required.
[0011]
In recent years, environmental issues have been regarded as important, and a coating composition for an ink roller corresponding to the environmental problem has been demanded.
[0012]
[Problems to be solved by the invention]
SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems, and even after printing is interrupted, printing can be resumed with little adjustment, and an environmentally friendly coating composition for an ink roller, and It is to provide an ink roller protection method used.
[0013]
[Means for Solving the Problems]
That is, the present invention is (1) a coating composition for an ink roller comprising a binder resin for a lithographic ink and at least one vegetable oil selected from semi-drying oil and non-drying oil, wherein the vegetable oil is fully coated. It is related with the coating composition for ink rollers characterized by containing 5 to 80weight% in an agent composition.
[0014]
Furthermore, the present invention relates to (2) a coating composition for an ink roller as described in the above item (1), which further contains an inorganic pigment and / or an organic pigment.
[0015]
Furthermore, the present invention relates to (3) an ink roller protection method, wherein the ink roller coating composition according to any one of (1) and (2) above is applied to an ink roller of a lithographic printing press. .
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail.
[0017]
The binder resin for the ink roller coating composition of the present invention is a lithographic ink. This is to make the composition of the coating composition for an ink roller of the present invention as close as possible to the composition of the lithographic ink, and to reduce the influence on the printed matter even if it is mixed in the lithographic ink to be used.
[0018]
Examples of the lithographic ink binder resin used in the present invention include petroleum resins, phenol resins, rosin-modified phenol resins, various alkyd resins, rosin maleic acid resins, polyester resins, cyclized rubber, and the like, or modified products thereof. These binder resins can be used alone or in combination of two or more.
[0019]
The binder resin for lithographic ink is usually contained in the total ink roller coating composition in an amount of 5 to 40% by weight, preferably 15 to 40% by weight.
[0020]
Examples of at least one vegetable oil selected from semi-drying oil and non-drying oil used in the present invention include soybean oil, rapeseed oil, cottonseed oil, olive oil, castor oil and the like. These vegetable oils can be used alone or in combination of two or more. The vegetable oil is usually contained in the entire ink roller coating composition in an amount of 5 to 80% by weight, preferably 35 to 60% by weight.
[0021]
When the content of the vegetable oil is less than the above range, the effect of preventing the diameter reduction of the ink roller and the effect of preventing the tackiness (abrupt increase in viscosity) of the coating composition for the ink roller 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 the ink roller becomes low, and it becomes difficult to coat the roller.
[0022]
Mineral oil can be used in combination with the coating composition for an ink roller of the present invention as long as the performance does not deteriorate as required. Among these, mineral oil having a boiling point temperature of 350 ° C. to 490 ° C. can be preferably used.
[0023]
As a 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 Oil Co., Ltd. Sankyo Ink Oil 145 (boiling range 398 ° C. to 488 ° C.), Nippon Oil Co., Ltd. Nisseki Ink Oil 20 (boiling point range 352 ° C. to 485 ° C.) and the like can be mentioned.
[0024]
When mineral oil having a boiling range lower than the above range is used, it is tucked up on a roller, and, as will be described later, when the coating composition is removed by using a printing material such as paper at the start of reprinting, paper wrapping Problems such as troubles are likely to occur. Moreover, when the mineral oil whose boiling point range is 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 it at the start of reprinting.
[0025]
In this invention, an inorganic pigment and / or an organic pigment can be mix | blended as needed.
[0026]
Inorganic pigments include calcium carbonate, precipitated barium sulfate, white carbon, silica, alumina white, aluminum hydroxide, kaolin, clay, talc, bentonite and other white pigments, titanium oxide, zinc white and other white pigments, carbon black, iron Colored pigments such as black, red bean, and bitumen.
[0027]
As organic pigments, insoluble azo pigments, azo lake pigments, condensed azo pigments, phthalocyanine pigments, quinacridone pigments, isoindolinone pigments, isoindoline pigments, dioxazine pigments and the like are generally used in lithographic inks. Pigments can be used.
[0028]
When these pigments are used, they can be blended in a ratio of 5 to 50% by weight, preferably 5 to 35% by weight, in the coating composition for all ink rollers. When a pigment is blended, it is preferable to use a color similar to the color of the printing ink to be used, so that even if it is mixed in the printing ink, the influence on the printed matter can be reduced.
[0029]
In the present invention, if necessary, a drying inhibitor can be used in combination in the coating composition for an ink roller.
[0030]
Examples of the drying inhibitor include phenolic antioxidants such as 2,6-di-t-butyl-3-methylphenol (BHT), styrenated phenol, and n-octadecyl-3- (3,5-di-t. -Butyl-4-hydroxyphenyl) propionate, eugenol, pyrogallol, catechol, guaiacol and the like. Examples of quinone include 2-t-butylhydroquinone and hydroquinone. Examples of amines include alkylated diphenylamine. When using a drying inhibitor, it is preferable to contain 1% by weight or less in the coating composition for all ink rollers.
[0031]
Among the ink roller coating composition of the present invention, a preferred composition comprises 15-40% by weight of an ink binder resin, 35-60% by weight of vegetable oil, 5-50% by weight of pigment, and does not contain mineral oil. When mineral oil is contained, it contains 1 to 10% by weight of mineral oil having a boiling range of 350 to 490 ° C., and further contains no drying inhibitor or 1% by weight or less.
[0032]
One embodiment of the ink roller protection 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 make a non-contact state, and the ink transfer roller 3 is placed on the ink transfer roller 3 with a spatula or the like. 5, 6 and the ink form roller 7 are transferred to each roller while rotating at a low speed to coat. It is also preferable to install a supply device 9 for the ink roller coating composition on the ink transfer roller 3 and transfer the ink roller coating composition to each of the rollers 4, 5, 6, and 7. This is one of the embodiments. The coating amount of the ink roller for coating composition is not particularly limited, and is usually in the range of 5 to 30 g / m ² is preferred.
[0033]
Next, when printing is resumed, normal printing operation is performed using a printing medium such as paper, thereby transferring the coating composition for the ink roller on the ink roller along with the newly supplied printing ink through the blanket. Remove. Since the coating composition for 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 paper wrapping, and it is a composition close to the printing ink composition, so printing Even if it is mixed in ink, there is little influence on the printed matter, and a good printed matter can be obtained immediately without any special removal operation.
[0034]
The protection method of the present invention prevents the diameter of the ink roller from being reduced when the printing machine is stopped, the change in the roller nip of the various ink rollers is small, and the tack-up of the coating composition for the ink roller is also small. There is no need to readjust the pressure between the rollers, and if the ink discharge 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 is possible in a short time, and the work time is greatly increased. Can be shortened.
[0035]
【Example】
EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to these Examples. In the examples, parts and% represent parts by weight and% by weight, respectively.
[0036]
<Examples of varnish production>
[Varnish A]
A four-necked flask equipped with a stirrer, condenser and thermometer, 40 parts Tamanol 361 (rosin-modified phenolic resin, Arakawa Chemical Industries, Ltd.), No. 6 solvent (mineral oil with a boiling range of 294 ° C to 345 ° C, Japan 40 parts of Petrochemical Co., Ltd. (hereinafter referred to as “mineral oil A”) and 20 parts of polymerized linseed oil were charged, heated with heating while blowing nitrogen gas, and stirred at 200 ° C. for 30 minutes to obtain 100 parts of varnish A.
[0037]
[Varnish B]
A four-necked flask equipped with a stirrer, condenser and thermometer was charged with 40 parts of Tamanol 361 (rosin-modified phenolic resin, Arakawa Chemical Industries, Ltd.), 40 parts of No. 6 solvent and 20 parts of soybean oil, and nitrogen gas. And heated at 200 ° C. for 30 minutes to obtain 100 parts of varnish B.
[0038]
[Varnish C]
A four-necked flask equipped with a stirrer, condenser and thermometer was charged with 40 parts of Tamanol 361 and 60 parts of soybean oil, heated with heating while blowing nitrogen gas, and stirred at 200 ° C. for 30 minutes to obtain 100 parts of varnish C. It was.
[0039]
[Example 1]
After premixing 25 parts of varnish A, 30 parts of varnish B, 30 parts of white glaze CC (calcium carbonate, manufactured by Shiraishi Kogyo Co., Ltd.) and 7.5 parts of mineral oil, the mixture was kneaded with three rolls. Next, 7 parts of Sankyo ink oil 145 (boiling range: 398 ° C. to 488 ° C., manufactured by Sankyo Oil Chemical Co., Ltd., hereinafter referred to as “mineral oil B”) and 0.5 part of BHT (drying inhibitor) were added to continue the kneading. The kneaded meat was adjusted with three rolls to obtain a coating composition 1 for an ink roller.
[0040]
[Example 2]
After 55 parts of varnish B, 30 parts of white luster CC and 7.5 parts of mineral oil A were premixed, the mixture was kneaded with three rolls. Subsequently, 7 parts of mineral oil and 0.5 part of BHT were added, the meat was continued and the meat was adjusted with 3 rolls to obtain a coating composition 2 for an ink roller.
[0041]
[Example 3]
After preliminarily mixing 55 parts of varnish C, 30 parts of white luster CC and 15 parts of mineral oil A, the mixture was adjusted with three rolls to obtain a coating composition 3 for an ink roller.
[0042]
[Example 4]
In Example 3, it adjusted similarly except having replaced 7 parts of mineral oil A with mineral oil B, and obtained the coating composition 4 for ink rollers.
[0043]
[Example 5]
In Example 3, it adjusted similarly except having substituted 7 parts of mineral oil A with soybean oil, and obtained the coating composition 5 for ink rollers.
[0044]
[Example 6]
After premixing 55 parts of varnish C, 30 parts of white luster CC and 8 parts of soybean oil, the mixture was kneaded with three rolls. Next, 6.5 parts of mineral oil A and 0.5 part of BHT were added, the meat was continued and the meat was adjusted with three rolls to obtain a coating composition 6 for an ink roller.
[0045]
[Example 7]
A coating composition 7 for ink roller was obtained in the same manner as in Example 3, except that 7 parts of mineral oil A was replaced with soybean oil and 8 parts of mineral oil A were replaced with mineral oil B.
[0046]
[Example 8]
In Example 3, it adjusted similarly except having replaced 15 parts of mineral oil A with soybean oil, and obtained the coating composition 8 for ink rollers.
[0047]
[Example 9]
In Example 3, adjustment was carried out in the same manner except that 15 parts of the mineral oil A was replaced with rapeseed oil to obtain a coating composition 9 for an ink roller.
[0048]
[Example 10]
After 15 parts of varnish B, 80 parts of varnish C and 5 parts of soybean oil were preliminarily mixed, the kneaded meat was adjusted with three rolls to obtain a coating composition 10 for an ink roller.
[0049]
[Comparative Example 1]
After premixing 55 parts of varnish A, 30 parts of white glaze CC and 15 parts of linseed oil, the mixture was adjusted with three rolls to obtain a coating composition 11 for an ink roller.
[0050]
[Comparative Example 2]
After 40 parts of varnish A, 15 parts of varnish B, 30 parts of white gloss flower CC and 7.5 parts of mineral oil were premixed, the mixture was kneaded with three rolls. Subsequently, 7 parts of mineral oil and 0.5 part of BHT were added, the meat was continued and the meat was adjusted with three rolls to obtain a coating composition 12 for an ink roller.
[0051]
[Comparative Example 3]
After premixing 55 parts of varnish A, 30 parts of white luster CC and 7 parts of mineral oil A, the mixture was kneaded with three rolls. Next, 7 parts of mineral oil and 1 part of BHT were added, the meat was continued and the meat was adjusted with three rolls to obtain a coating composition 13 for an ink roller.
[0052]
[Comparative Example 4]
After premixing 53 parts of varnish A, 23 parts of white luster CC and 7 parts of mineral oil A, the mixture was kneaded with three rolls. Subsequently, 7 parts of mineral oil and 10 parts of BHT were added, the meat was continued and the meat was adjusted with three rolls to obtain a coating composition 14 for an ink roller.
[0053]
The compositions of the ink roller coating compositions 1 to 14 are shown in Table 1. Table 2 shows the content of each oil component in the coating composition for all ink rollers.
[0054]
[Evaluation methods and results]
(1) After printing on a roller nip change lithographic printing machine, the printing is interrupted, and the ink roller coating composition 1-14 is coated on the ink roller at a coating amount of 5 g / m ² , and at room temperature for 10 days. The condition was confirmed after being left.
[0055]
Evaluation ○: The roller diameter is hardly thin and there is no need for pressure adjustment.
X: The roller diameter is narrow and needs to be adjusted.
[0056]
(2) Viscosity change on roller Coating compositions 1 to 14 for ink rollers were applied on a rotating roller of an incometer, and changes in the viscosity of each coating film were evaluated by touch for 10 hours every hour.
[0057]
Evaluation ◯: Unchangeable △: Feeling a little sticky ×: Hardly changing [0058]
(3) The coating composition 1-14 for ink rollers was coated on a drying glass plate using a 3 mils application rod, and the drying property of each coating film at 35 ° C. was evaluated.
[0059]
Evaluation ○: No drying even after 30 days ×: Drying after 30 days or less The test results are shown in Table 1.
[0060]
[Table 1]

[0061]
[Table 2]

[0062]
【The invention's effect】
The coating composition for the ink roller of the present invention is more environmentally friendly than the conventional one, and by applying this to the ink roller at the time of printing interruption of the lithographic printing machine, the roller diameter is reduced so far at the start of reprinting, Although it took a long 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 ink roller coating composition of the present invention has less change in viscosity on the roller and can be dried more slowly than conventional ink roller coating compositions. Furthermore, since the coating composition for an ink roller of the present invention is a composition close to printing ink, even if mixed in printing ink, there is little influence on the printed matter, and a good printed matter can be obtained immediately without any special removal operation. .
[Brief description of the drawings]
FIG. 1 is a schematic diagram showing an ink supply unit of a lithographic printing apparatus.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Ink fountain 2 Ink taking-out roller 3 Ink transfer roller 4, 5 Ink kneading roller 6 Ink kneading roller 7 Inking roller 8 Plate cylinder 9 Coating agent supply apparatus

Claims (3)

A coating composition for an ink roller containing a binder resin for lithographic ink and at least one vegetable oil selected from semi-drying oil and non-drying oil, wherein the vegetable oil is contained in the total coating composition in an amount of 5 to 80 A coating composition for an ink roller, comprising: wt%. Furthermore, the coating composition for ink rollers of Claim 1 containing an inorganic pigment and / or an organic pigment. A method for protecting an ink roller, comprising applying the coating composition for an ink roller according to claim 1 or 2 to an ink roller of a lithographic printing machine.

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