JP2003237205A - Porous rubber printing body - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a porous rubber printing body generating no tar-like rubber refuse at the time of carving due to laser processing and capable of performing sufficient carving having depth in various laser processings. <P>SOLUTION: A master batch is prepared by kneading a rubber composition, 1-3 phr of carbon black, a water soluble compound, a vulcanizer, a filler and, if necessary, additives and, after this master batch is vulcanized, the water soluble compound is removed to obtain the porous rubber printing body. <P>COPYRIGHT: (C)2003,JPO

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a porous rubber printed body having open cells used for a penetrating mark of a built-in ink type. The present invention relates to a porous rubber print. 2. Description of the Related Art Penetration stamps, which can be continuously printed without using a stamp table each time they are used by using a porous rubber having countless open cells as a printing body, are widely used. From the applicant, Japanese Patent Publication No. 59-281
93, and JP-B-59-29606. Such a porous rubber can contain a large amount of ink even with a pigment ink having a relatively high viscosity, and boasts a good ink ejection amount. Recently, a method of engraving a stamped surface with a laser beam machine using a carbon dioxide gas laser or a YAG laser has been proposed as a method for processing the stamped surface of such a penetrating mark. 161183 and JP-A-2000-52075. However, since a printing body usually used in laser processing is made of porous rubber containing a large amount of carbon black, there is a disadvantage that a large amount of tar-like rubber scum is generated during engraving of a stamp surface. This rubber residue may be ignited by a laser, and may cause ink discoloration as well as clogging of the ink when it is made into a printed body. Therefore, a suction, cleaning and drying treatment device for removing the rubber residue. Had to be installed separately. On the other hand, a transparent or white porous rubber for laser processing that does not use carbon black at all is known. However, since this porous rubber cannot sufficiently absorb a carbon dioxide gas laser, it has a sufficient depth of engraving. Could not. Further, this porous rubber could not be engraved at all because it transmitted YAG laser. [0003] Accordingly, the present invention is directed to a porous rubber printed body that does not generate tar-like rubber scum when engraving by laser processing, and has a large depth in various laser processing. It is an object of the present invention to provide a porous rubber printed body capable of performing engraving with sufficient quality. [0004] In order to solve the above-mentioned problems, a rubber composition, 1 to 3 phr of carbon black, a water-soluble compound, a vulcanizing agent, a filler and, if necessary, an additive. The present invention provides a porous rubber print body obtained by kneading a master batch, vulcanizing the master batch, and removing a water-soluble compound. In the porous rubber printed body for laser processing according to the present invention, almost no rubber residue is generated or only a very small amount of rubber residue is generated during laser processing. Therefore, it is possible to remove all the rubber residue only by sucking the surface of the printed body. it can. Therefore, a cleaning device and a drying device for the printed body are not required. In addition, since the carbon black that is slightly dispersed absorbs the laser beam sufficiently and efficiently, engraving with a sufficient depth can be performed in various types of laser processing. Hereinafter, the present invention will be described in detail. As the rubber composition that can be used in the present invention, natural rubber,
Styrene-butadiene rubber, acrylonitrile-butadiene rubber, chloroprene rubber, polyurethane rubber, acrylic rubber, ethylene-propylene-diene rubber, dimethyl silicone rubber, methylphenyl silicone rubber, methyl vinyl silicone rubber, and the like can be used. In the present invention, 1 to 3 phr of carbon black is blended. The thus formed porous rubber print for laser processing hardly generates any rubber scum or generates only a very small amount of rubber scum during laser processing. Therefore, it is possible to remove all the rubber scum by merely suctioning the print body surface. Therefore, a cleaning device and a drying device for the printed body are not required. If the amount of carbon black is less than 1 phr, the absorption amount of the laser beam is not sufficient, and the processing amount and engraving depth of the porous rubber print are insufficient. If it exceeds 3 phr, steps for washing and drying are required, which is not preferable. [0008] Examples of the water-soluble compound that can be used in the present invention include fine powders such as salts and sugars. Salt is easy to pulverize, and the vulcanization temperature of rubber (110 ° C)
(160 ° C. to 160 ° C.), which means an inorganic compound which does not decompose into gas and can be easily removed with water after heating. Specifically, metal salts such as sodium chloride, sodium sulfate and sodium nitrate are preferably used. The diameter is usually 32
３５０350 mesh (0.044〜0.498 mm), and the usage ratio is about 20 parts per 100 parts of rubber.
0 to 1200 parts are used, and particularly 400 to 600 parts are preferably used. The sugar can be any of monosaccharides such as pentose and hexose, disaccharides such as saccharose and maltose, and polysaccharides such as starch and glycogen.
Further, these can be used in combination. The particle size is usually 150 mesh pass (0.010 to 0.103
mm). Among them, starch is particularly preferably used because it is excellent in solubility, a powder having a uniform required particle size can be easily obtained, and it is inexpensive. The usage ratio is about 50-3 for 100 parts of rubber.
00 parts, preferably 100 to 200 parts. These sugars swell under the influence of heat during vulcanization and generate the contained trace moisture as a gas. Then, this gas acts as a kind of blowing agent and gives good results for bubble formation. As the water-soluble compound, a salt and a sugar may be used alone or in combination, and may be appropriately selected depending on the application. When used in combination, the compounding weight ratio of salt to sugar is preferably about 9: 1 to 3: 1, particularly preferably 4: 1. In the present invention, the reason why the mixing weight ratio of the salt and the sugar is set in such a range is that if the amount of the sugar is too large, the amount of moisture and carbon dioxide gas generated during vulcanization increases, and these excessively generate bubbles. This is because the bubbles of the porous rubber may become non-uniform, and the decomposition of the sugar itself may proceed too much to render the mixture impossible to mold in the mold. On the other hand, if the amount of sugar is too small, the sugar particles do not intervene properly between the salt particles, and the effect of the sugar cannot be sufficiently exhibited. The vulcanizing agent that can be used in the present invention includes sulfur vulcanizing agents such as precipitated sulfur, sulfur, selenium, tellurium, and sulfur chloride, t-butylcumyl peroxide, dicumyl peroxide, 5-dimethyl-2,5-di- (t-butylperoxy) hexane, 1,3 bis (t
Publicly known vulcanizing agents (sometimes referred to as crosslinking agents) such as peroxides such as -butylperoxy-i-propyl) benzene, which can be used alone or in combination of two or more. You can also. About 2 to 5 parts of vulcanizing agent can be used with respect to 100 parts of rubber.
Four parts are particularly preferred. [0010] Fillers which can be used in the present invention include clay, talc, silica, mica, silicic acid, magnesium silicate, calcium silicate, calcium carbonate, magnesium carbonate, titanium dioxide, silicon oxide, antimony oxide, tin oxide, Examples include metal oxide-coated mica in which mica is coated with black iron oxide, red iron oxide, or the like. The usage ratio is about 0.1 to 60 parts per 100 parts of rubber. Further, in the present invention, additives and the like usually used in rubber production can be used as required.
For example, an effective amount of an amine-based anti-aging agent, a softening agent such as petrolatum or a plasticizer, a vulcanization aid such as zinc white, a guanidine-based vulcanization accelerator, or the like can be added. Further, as a lubricant, polyethylene glycol, polypropylene glycol, polyethylene glycol-polypropylene glycol copolymer, polyethylene glycol alkyl ether, polypropylene glycol alkyl ether, polyvinyl alcohol, polyallylamine, paraffin,
Effective amounts of waxes, higher fatty acids, fluorine-based surfactants, silicone-based surfactants, nonionic surfactants and the like can also be added. Also, an appropriate amount of organic synthetic fibers can be added. Examples of the organic synthetic fibers include polyethylene terephthalate fiber, polyacrylonitrile fiber, acrylic fiber, aliphatic polyamide fiber such as nylon 6, nylon 6/6, nylon 4/6, nylon 6/10, nylon 11, polypropylene fiber, and polyethylene. Fiber, polyvinyl alcohol fiber, polyvinyl chloride fiber,
Polyvinylidene chloride fiber, polyurethane fiber, polyalkylparaoxybenzoate fiber, polytetrafluoroethylene fiber, aramid fiber, wholly aromatic polyester fiber, poly-p-phenylenebenzobisthiazole fiber,
Poly-p-phenylene benzobisoxazole fiber, polybenzimidazole fiber, polyoxymethylene fiber or the like can be used, and staples having a fiber length of 0.2 to 2 mm are used. In addition, as these organic synthetic fibers, those having a fineness of 0.1 to 100 d are particularly preferably used. Next, a method for producing a porous rubber printed body will be described. The respective raw materials are put into a kneader and kneaded to form a master batch. Next, an unvulcanized sheet is prepared by adjusting the shape using a calender roll or a press. Next, the sheeted masterbatch is put into a mold, and is placed for about
The composition is heated and vulcanized at a temperature of from 1 to 160C. Known heating means can be used. For example, electric heating or steam heating can be used. Next, the water-soluble compound is taken out from the mold, and the water-soluble compound is washed out while repeating compression and expansion restoration using cold water or hot water. Then, a porous rubber sheet having open cells can be obtained. Next, after engraving a stamped surface on the porous rubber sheet using a carbon dioxide laser processing machine or a YAG laser processing machine, the porous rubber printed body of the present invention can be obtained by cutting into an appropriate size. The porous rubber print of the present invention can be used not only as a single-layer rubber print, but also as an upper layer (ink holding portion) and a lower layer (print portion).
It can also be used as an upper layer (ink holding portion) and / or a lower layer (printing portion) of a rubber printed body composed of layers. However, the water-soluble compound for the upper layer is slightly larger than the water-soluble compound for the lower layer. This is because the diameter of the bubbles in the upper layer becomes larger than the diameter of the bubbles in the lower layer. Therefore, when the ink is impregnated, the ink can be stably supplied to the lower layer by capillary action. Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited by these examples. (Example 1) Synthetic rubber (NBR) 100 parts, sulfur 3.5
Parts, zinc white 5 parts, vulcanization accelerator 5 parts, liquid rubber (low polymerization N
Softener 30 consisting of BR molecular weight), petrolatum, DBP, etc.
Parts, 2 parts of carbon black (2 phr), silica 28
Part, antioxidant 2 parts, 80-100 mesh (0.14
9 to 0.176 mm) sodium chloride 800 parts, 15 parts
200 parts of starch of 0 to 250 mesh (0.062 to 0.103 mm) is added and kneaded to form a master batch,
This was made into a flat sheet having a thickness of 5 mm using a calender roll. Next, the sheet was accommodated in a smooth mold. Next, a pressure of about 200 kg / cm ² was applied to sandwich the plate between hot plates, and vulcanized at a temperature of 100 ° C. for 60 minutes.
After vulcanization, the mold was released, washed thoroughly with water until sodium chloride and starch were completely removed, and dehydrated and dried to obtain a porous rubber sheet. A YAG laser processing machine (output: 60 W, processing speed: 500 mm / sec) is applied to the porous rubber sheet body.
When engraved in c), almost no rubber residue was generated,
There was no need to clean the stamp. The engraving depth is 1m
m were obtained. After that, the porous rubber print obtained by cutting into an appropriate size was 500 to 2000 mPa · s (25
° C), and the ink was absorbed and pigmented. The ink was discolored, the amount of ink absorbed was sufficient, and clear printing without bleeding or blurring could be performed over a long period of time. (Example 2) Synthetic rubber (NBR) 100
Parts, 3.5 parts of sulfur, 5 parts of zinc white, 5 parts of vulcanization accelerator, 30 parts of a softening agent composed of liquid rubber (low polymerization NBR), vaseline, DBP, etc., 3 parts of carbon black (3 phr), 27 parts of silica 2 parts of antioxidant, 200-350 mesh (0.044-0.074 mm) sodium chloride 40
0 parts, 200 mesh (0.010-0.074mm)
100 parts of starch, fiber length 0.9mm, diameter 0.01
10 parts of 1 mm aramid fiber was added and kneaded to obtain a master batch A, which was formed into a flat sheet A having a thickness of 2 mm by a calender roll. Separately, synthetic rubber (N
BR) 100 parts, sulfur 3.5 parts, zinc white 5 parts, vulcanization accelerator 5 parts, liquid rubber (low polymerization NBR), petrolatum, DBP
30 parts of a softening agent, 50 parts of carbon black, 2 parts of an antioxidant, 32 to 100 mesh (0.149 to
0.498 mm) of sodium chloride, 800 parts of aramid fiber having a fiber length of 1.1 mm and a diameter of 0.013 mm were treated with ultra-high NBR to 10 phr and kneaded to obtain a master batch B, which was calendered. A flat sheet B having a thickness of 5 mm was formed using a roll. Next, the sheet B was superimposed on the sheet A and housed in a smooth mold. Next, a pressure of about 200 kg / cm ² was applied to sandwich the platens between hot plates, and vulcanized at a temperature of 150 ° C. for 15 minutes.
After vulcanization, the mold was released, washed thoroughly with water until sodium chloride and starch were completely removed, and dehydrated and dried to obtain a porous rubber sheet. The porous rubber sheet body manufactured in this way becomes a printed body in which the sheet A and the sheet B are integrated, and the sheet A is a printing section and the sheet B is an ink holding section. From the sheet A (printing portion) side of the porous rubber sheet body, a YAG laser processing machine (output: 60 W, processing speed: 50)
When engraving was performed at 0 mm / sec), almost no rubber residue was generated, and there was no need to clean the stamp face. The engraving depth was 1 mm. Thereafter, the porous rubber printed body obtained by cutting into an appropriate size is 500-2000.
When a pigment ink with a high viscosity of mPa · s (25 ° C) is absorbed and printed, the ink is not discolored, the ink absorption amount is sufficient, and clear printing without bleeding or blurring is performed over a long period of time. I was able to. (Example 3) 100 parts of methyl vinyl silicone rubber, 5 parts of t-butylcumyl peroxide, 10 parts of silica, 10 parts of polyethylene glycol, 2 parts of carbon black (2 phr), 80 to 100 mesh (0.
149-0.176 mm) of sodium chloride,
150-250 mesh (0.062-0.103m
100 parts of the starch of m) were added and kneaded to form a masterbatch, which was once pulverized and formed into a flat sheet having a thickness of 5 mm by pressing. Next, the sheet was accommodated in a smooth mold. Then, a pressure of about 200 kg / cm ² is applied to press the platens between the hot plates, and at a temperature of 100 ° C., 60
Vulcanized for minutes. After vulcanization, the mold was released, washed thoroughly with water until sodium chloride and starch were completely removed, and dehydrated and dried to obtain a porous rubber sheet. A YAG laser processing machine (output: 60 W, processing speed: 50)
When engraving was performed at 0 mm / sec), almost no rubber residue was generated, and there was no need to clean the stamp face. The engraving depth was 1 mm. Thereafter, the porous rubber printed body obtained by cutting into an appropriate size is 500-2000.
When a pigment ink with a high viscosity of mPa · s (25 ° C) is absorbed and printed, the ink is not discolored, the ink absorption amount is sufficient, and clear printing without bleeding or blurring is performed over a long period of time. I was able to. The porous rubber print of the present invention does not generate tar-like rubber scum when engraving by laser processing.
There is no danger of the rubber residue being ignited by the laser, and there is no danger of the ink filling the rubber print after laser processing being clogged and discoloring the ink. Further, there is no need to separately install a cleaning device and a drying device for removing the rubber residue. In addition, since the carbon black slightly dispersed in the porous rubber printing material absorbs the laser beam sufficiently and efficiently, the porous rubber printing material has an excellent effect that sufficient depth engraving can be obtained in various laser processing. It is.

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Claims (1)

Claims: 1. A master batch is prepared by kneading a rubber composition, 1 to 3 phr of carbon black, a water-soluble compound, a vulcanizing agent, a filler, and additives as necessary. And a porous rubber print obtained by vulcanizing the master batch and removing water-soluble compounds.