JP6602144B2 - Rubber roller regeneration agent - Google Patents

Description

  The present invention relates to a rubber roller regenerating agent.

  Offset printing is a printing method that utilizes the property that an oil-based ink composition for offset printing (hereinafter abbreviated as “ink” as appropriate) repels water, and a relief printing method that uses a printing plate with irregularities. Unlike the above, a printing plate having an unevenness and having an oleophilic image portion and a hydrophilic non-image portion is used. When printing using this printing plate, first, a dampening solution is brought into contact with the printing plate to form a water film on the surface of the non-image area, and then the ink composition is supplied to the printing plate. Then, the supplied ink composition does not repel and adhere to the non-image area where the water film is formed, but adheres only to the oleophilic image area. Thus, an image of the ink composition is formed on the surface of the printing plate, and then printing is performed by sequentially transferring it to the blanket and paper.

  In a printing machine used in such offset printing, printing is performed by successively transferring ink from an ink supply source to a printing plate via a plurality of rollers. The roller used here includes a rubber roller and a metal roller. In printing, a rubber roller having rubber elasticity is combined in a state of being pressed strongly against the metal roller. Such pressing pressure of the rubber roller against the metal roller is called nip pressure. By applying an appropriate nip pressure between the rubber roller and the metal roller, the ink is kneaded between the two to make it suitable for printing, and the ink is properly transferred between the rollers. As a result, good printing can be realized. Similarly, the fountain solution is supplied to the printing plate by a roller group in which a metal roller and a rubber roller are combined.

  This rubber roller is formed by wrapping rubber around a metal or resin shaft. As rubber to be wound, for example, synthetic rubber such as nitrile rubber (NBR) is used. These rubbers contain a plasticizer in order to obtain appropriate rubber elasticity, and eventually the plasticizer contained in the rubber is extracted by the ink while it is kept in contact with the oily ink during printing. As a result, the proper amount of plasticizer in the rubber cannot be maintained. In such a state, the rubber hardness on the surface of the rubber roller increases from the initial set hardness and the rubber diameter decreases, making it difficult to apply an appropriate nip pressure during printing, and the rubber roller reaches the end of its life. become. Thus, the rubber roller which has been used for a certain period and has reached the end of its life can be recycled and used by replacing the rubber on the peripheral surface. However, the rewinding work of rubber in the rubber roller generates enormous parts costs and work costs.

  As a solution to such a problem, for example, in Patent Document 1 below, a urethane rubber single layer is formed on a roller core, and the rubber hardness of the urethane rubber single layer is 25 ° C. Inking rollers have been proposed that are sometimes set to 40-45 degrees. For example, Patent Document 2 below proposes a method for repairing a rubber roller, in which the surface of the rubber roller is polished with a minimum cutting allowance, and then a new unvulcanized rubber is wound and vulcanized and molded by a die press. ing.

Japanese Patent Laid-Open No. 10-272765 JP 09-155427 A

  However, although the rubber roller described in Patent Document 1 can be expected to have a longer life than that of the conventional one, the life of the rubber roller is not changed until the plasticizer is extracted from the rubber surface. Further, the procedure shown in the method for regenerating a rubber roller described in Patent Document 2 is not necessarily simple and still requires a corresponding cost.

  The present invention has been made in view of the above situation, and an object of the present invention is to provide a rubber roller regenerating agent that can regenerate the rubber roller by reducing the hardness of the rubber while suppressing an increase in the regeneration cost.

  As a result of diligent studies to solve the above-mentioned problems, the present inventors have swallowed them with mechanical pressure while supplying a liquid containing a predetermined ester compound to the surface of the rubber roller to be regenerated. As a result, it was found that the flexibility of rubber and the diameter of the thinned rubber roller can be recovered, and a rubber roller regenerating agent effective for such treatment was completed. The present invention has been made based on the above findings, and provides the following.

The present invention is seen containing at least one a compound identified compound (s) is selected from the group consisting of diester compounds of dicarboxylic acids and monoester compounds of the dicarboxylic acids, in contact with the surface of a processed rubber roller It is a rubber roller regenerating agent that is used.

  The specific compound (group) is preferably at least one compound selected from the group consisting of an aliphatic dicarboxylic acid diester compound and an aliphatic dicarboxylic acid monoester compound.

  The specific compound (group) is preferably at least one compound selected from the group consisting of diester compounds of aliphatic dicarboxylic acids.

  The aliphatic dicarboxylic acid is preferably at least one compound selected from the group consisting of malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid and sebacic acid.

  The specific compound (group) is preferably at least one compound selected from the group consisting of succinic acid dimethyl ester, glutaric acid dimethyl ester and adipic acid dimethyl ester.

  ADVANTAGE OF THE INVENTION According to this invention, the rubber roller regeneration agent which can reduce the hardness of rubber | gum and can reproduce | regenerate a rubber roller, suppressing the increase in regeneration cost is provided.

FIG. 1 is a cross-sectional view schematically showing an example of a method for using the rubber roller regenerating agent of the present invention.

  Hereinafter, an embodiment of the rubber roller regenerating agent according to the present invention will be described. The present invention is not limited to the following embodiments, and can be implemented with appropriate modifications within the scope of the present invention.

  The rubber roller regenerating agent of the present invention is used for regenerating a rubber roller that has lost its plasticizer and has increased hardness and poor elasticity. Typically, examples of such a rubber roller include an ink roller used in an offset printing machine and each roller of a fountain solution device, but are not particularly limited.

  The rubber roller regenerating agent of the present invention is characterized by comprising a specific compound (group) comprising at least one compound selected from the group consisting of diester compounds of dicarboxylic acids and monoester compounds of dicarboxylic acids. Here, “specific compound (group)” in the present invention means “specific compound or specific compound group”. That is, in the present invention, the compound designated as “specific compound (group)” is selected from the group consisting of a diester compound of dicarboxylic acid and a monoester compound of dicarboxylic acid, which may be one kind or two or more kinds, In this case, it means “specific compound”, and in the case of two or more types, it means “specific compound group”.

  The dicarboxylic acid is an organic compound having two carboxyl groups, and the diester compound of the dicarboxylic acid used in the present invention is obtained by esterifying both of the two carboxyl groups in the dicarboxylic acid. Is one in which either one of the two carboxyl groups in the dicarboxylic acid is esterified. Examples of such esters include alkyl esters having about 1 to 10 carbon atoms that may have a branch, and more specifically, methyl esters, ethyl esters, n-propyl esters, isopropyl esters, n-butyls. Examples include esters, isobutyl esters, tert-butyl esters, sec-butyl esters, pentyl esters, hexyl esters, 2-ethylhexyl esters, heptyl esters, octyl esters, and the like.

  The specific compound (group) is preferably at least one compound selected from the group consisting of an aliphatic dicarboxylic acid diester compound and an aliphatic dicarboxylic acid monoester compound. Examples of such aliphatic dicarboxylic acids include compounds in which two carboxyl groups are bonded to a divalent group consisting of an aliphatic chain and / or an alicyclic ring, and the aliphatic chain has a branch. Preferable examples are alkylene groups having 2 to 10 carbon atoms. Although not particularly limited, examples of such aliphatic dicarboxylic acids include malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, and the like.

  More preferably, the specific compound (group) includes at least one compound selected from the group consisting of diester compounds of aliphatic dicarboxylic acids. That is, it is preferable that both of the two carboxyl groups contained in the aliphatic dicarboxylic acid are esterified.

  The content of the specific compound (group) in the rubber roller regenerating agent of the present invention is preferably about 50% by mass to 100% by mass, more preferably about 70% by mass to 100% by mass. More preferably, about 80 mass%-100 mass% can be mentioned. When the content of the specific compound (group) in the rubber roller regenerative agent is within the above range, the rubber hardness of the rubber roller to be recycled is reduced and the diameter of the thin rubber roller is restored to regenerate the rubber roller. Can be made.

  More preferably, the specific compound (group) includes at least one compound selected from the group consisting of dimethyl succinate, dimethyl glutarate, and dimethyl adipic acid, and includes all three of these compounds. It is particularly preferred. When all of these three compounds are included as the specific compound (s), the mass ratio of succinic acid dimethyl ester, glutaric acid dimethyl ester and adipic acid dimethyl ester is as follows: succinic acid dimethyl ester: glutaric acid dimethyl ester: adipic acid dimethyl ester 1 to 2: 1 to 4: 1 to 2 is preferable, about 1: 1 to 3: 1 is more preferable, and about 1: 2: 1 is more preferable.

  In addition to the above specific compound group, the rubber roller regenerating agent of the present invention may further contain other components for the purpose of improving suitability such as removal of glaze adhered to the surface of the rubber roller and handling properties. Examples of such compounds include alcohols, ethers, esters, water and the like. Glaze is a hydrophilic substance that adheres to the surface of a rubber roller over time when the rubber roller is used for printing. It is used to protect printing paper coating agents, chemicals contained in dampening water, and printing plates. Gum arabic, fine paper powder, etc. fixed. The surface of the rubber roller to which the glaze is attached is hydrophilized, and the ink adherence is lowered.

  As alcohol, methanol, ethanol, n-propanol, isopropanol, ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, pentaethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, tetrapropylene glycol, pentapropylene glycol, Examples include glycerin and the like.

  Ethers include ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, tetraethylene glycol monomethyl ether, tetraethylene glycol monoethyl ether. , Pentaethylene glycol monomethyl ether, pentaethylene glycol monoethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, tripropylene glycol monomethyl ether, tripropylene glycol Monoethyl ether, tetrapropylene glycol monomethyl ether, tetrapropylene glycol monoethyl ether, pentaethylene glycol monomethyl ether, pentaethylene glycol monomethyl ether, 1-methoxy-2-propanol and the like.

  Esters are components added separately from the specific compound (group), which is also an ester compound, and examples include propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, monoalkyl esters of fatty acids derived from vegetable oils, and the like. can do. Preferred examples of the fatty acid constituting the fatty acid monoalkyl ester compound include saturated or unsaturated fatty acids having 16 to 20 carbon atoms. Examples of such saturated or unsaturated fatty acids include stearic acid, isostearic acid, hydroxystearic acid, and olein. Preferred examples include acid, linoleic acid, linolenic acid, and eleostearic acid. As the alkyl group constituting the fatty acid monoalkyl ester compound, an alkyl group having 1 to 10 carbon atoms is preferably exemplified, and more specifically, methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, Preferred examples include a tert-butyl group and 2-ethylhexyl group. As said fatty acid, what originates in soybean oil can be used preferably.

  As content of the said other component in a rubber roller regenerating agent, about 0-50 mass% is mentioned preferably, About 0-30 mass% is mentioned more preferably.

  Next, an example of a method for using the rubber roller regenerating agent of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view schematically showing an example of a method for using the rubber roller regenerating agent of the present invention. FIG. 1 shows a state in which the rubber roller 1 and the metal roller 2 that are long are viewed from the axial direction.

  The rubber roller 1 to be reproduced is fixed so as to be able to rotate in the circumferential direction with a pressing force applied to the metal roller 2 that can rotate in the circumferential direction. The rubber roller 1 is provided with power (not shown) for rotating the rubber roller 1 in the circumferential direction, and rotates in a direction in which the metal roller 2 is wound, as indicated by an arrow in FIG. Then, the metal roller 2 in contact with the rubber roller 1 in a pressed state rotates as indicated by the arrow in FIG. By rotating in this way, the rubber roller 1 is subjected to a pressing force at a location where it is in line contact with the metal roller 2, and at the next moment, the pressing force at that location is released by rotation and another line contact is made. A pressing force is applied to the part that is being performed. Therefore, the rubber roller 1 receives a pressing force from the metal roller 2 along its circumferential direction and receives a stagnation due to mechanical pressure, that is, an intermittent pressing force that is released. Instead of driving the rubber roller 1 as described above, the metal roller 2 may be driven.

  A liquid discharge port 4 is provided above the rubber roller 1 and the metal roller 2 that are in contact with each other, and the rubber roller regenerating agent 5 of the present invention is discharged from the liquid discharge port 4. The discharged rubber roller regenerating agent 5 spreads along the contact portion between the rubber roller 1 and the metal roller 2 that are in line contact, and spreads evenly on the surface of the rotating rubber roller 1. In order to spread the rubber roller regenerating agent 5 more quickly on the surface of the rubber roller 1, the metal roller 2 may be swung so as to reciprocate in the axial direction.

  As described above, the rubber roller 1 has the rubber roller regenerating agent 5 on the surface thereof, and the rubber contraction due to pressing is repeated intermittently. As a result, the specific compound (group) contained in the rubber roller regenerating agent 5 is ). The permeated specific compound (group) acts in the same manner as the plasticizer lost from the rubber roller 1 to compensate for this. For this reason, the rubber roller 1 that has undergone such a treatment has its hardness lowered moderately and its diameter is restored to its original size, so that it can be used again for printing.

  Further, in the process of undergoing such a process, the glaze that is fixed to the surface of the rubber roller 1 is peeled off and floats on the surface of the rubber roller 1. Such glaze is removed by a glaze removal plate 3 provided in contact with the length direction of the rubber roller 1. Inside the glaze removal plate 3, a removal material such as a non-woven fabric is accommodated in order to scrape the glaze.

  The rubber roller regenerating agent of the present invention will be described more specifically with reference to the following examples, but the present invention is not limited to these examples.

[Example 1]
23 parts by mass of dimethyl succinate, 46 parts by mass of dimethyl glutarate, 23 parts by mass of dimethyl ester adipate, 0.5 parts by mass of methanol, 3.5 parts by mass of n-propanol, and 4 parts by mass of pentaethylene glycol monomethyl ether The resulting mixture was used as a rubber roller regenerating agent of Example 1.

[Comparative Example 1]
87 parts by mass of cycloalkane (mixture of cyclohexane and cyclopentane), 1 part by mass of ethanol, 10 parts by mass of n-propanol, and 2 parts by mass of 1-methoxy-2-propanol were mixed, and the resulting mixture was compared with that of Comparative Example 1. It was set as the processing agent.

[Comparative Example 2]
68 parts by mass of water, 10 parts by mass of lactic acid, 16 parts by mass of tripropylene glycol monomethyl ether, and 6 parts by mass of gum arabic were mixed, and the resulting mixture was used as the treating agent of Comparative Example 2.

  A rubber roller 1 to be recycled is installed in the apparatus having the configuration shown in FIG. 1, and a regeneration test of the rubber roller 1 is performed for each of the rubber roller regenerating agent of Example 1, the treating agent of Comparative Example 1, and the treating agent of Comparative Example 2. It was. The apparatus used was one manufactured by Mitsubishi Heavy Industries Printing Paper Machine Co., Ltd. Further, the nip pressure between the rubber roller 1 and the metal roller 2 is 11 mm (corresponding to 7 kg as a tangential force on the surface of the metal roller), and the liquid is used so that the rubber roller regenerating agent or the processing agent is evenly distributed over the entire surface of the rubber roller 1. The rubber roller 1 and the metal roller 2 were rotated over 30 minutes while adjusting the discharge speed from the discharge port 4.

  As a result of the above test, only when the rubber roller treating agent of Example 1 was used, the rubber roller after the treatment was regenerated to a state where its hardness was reduced and it could be used for printing. However, when the processing agents of Comparative Examples 1 and 2 are used, the rubber roller after the processing is not observed in any state from the state before the processing, and is not in a state where it can be used for printing. There wasn't.

DESCRIPTION OF SYMBOLS 1 Rubber roller 2 Metal roller 3 Glaze removal plate 4 Liquid discharge port 5 Rubber roller regeneration agent

Claims (5)

See containing at least one specific compound consisting of compound (s) is selected from the group consisting of diester compounds of dicarboxylic acids and monoester compounds of the dicarboxylic acid, to be used in contact with the surface of the rubber roller to be processed Characteristic rubber roller regenerant.   The rubber roller regenerating agent according to claim 1, wherein the specific compound (group) is at least one compound selected from the group consisting of a diester compound of an aliphatic dicarboxylic acid and a monoester compound of an aliphatic dicarboxylic acid.   The rubber roller regenerating agent according to claim 1 or 2, wherein the specific compound (group) is at least one compound selected from the group consisting of diester compounds of aliphatic dicarboxylic acids.   4. The aliphatic dicarboxylic acid is at least one compound selected from the group consisting of malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid and sebacic acid. Rubber roller regenerant.   The rubber roller regenerating agent according to any one of claims 1 to 4, wherein the specific compound (group) is at least one compound selected from the group consisting of dimethyl succinate, dimethyl glutarate and dimethyl adipate. .

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