JP4362409B2 - Porous rubber stamp with open cells - Google Patents

Description

  The present invention relates to a printing material used for an ink built-in type rubber permeation stamp.

A permeation stamp that uses porous rubber having countless open cells as a stamping material and can be continuously stamped without using a stamp stand each time it is used is widely used. Disclosure. Such a permeation mark of porous rubber can contain a large amount of ink even if it is a pigment ink having a relatively high viscosity, and boasts a good ink discharge amount.
However, the conventional porous rubber has innumerable open cells, so the hardness is low, and when excessive pressing force is applied to the penetrating mark at the time of stamping, the stamping surface is crushed, and the occluded stamp ink flows out excessively, In addition to the fact that the mark to be printed becomes thicker or smeared and it is difficult to perform clear marking, the stamp ink is consumed and the surface of the stamp is worn out, and continuous printing over a long period of time is impossible.
Therefore, in order to solve such drawbacks, the present applicant has increased the amount of sulfur or carbon black compounded in the rubber to increase the rubber hardness to 40 degrees or more and 80 degrees or less, and the phenol resin in the rubber. Japanese Unexamined Patent Publication No. 50-000919 comprising the second invention in which a synthetic resin powder such as xylene resin, epoxy resin, vinyl chloride, and styrene resin is blended to make the rubber hardness 40 degrees or more and 80 degrees or less is disclosed.
However, if a large amount of a vulcanizing agent such as sulfur or a filler such as carbon black or silica is used and kneaded with a raw rubber or other material using a kneader as in the first invention, a considerable hardness is already obtained at this point. As a result, it does not mix evenly with the raw rubber and other materials, but it also has to apply a considerable load when kneading with a kneader, or with a calender roll or an extruder, resulting in damage to the manufacturing machine. It was.
Also, the porous rubber obtained by blending the synthetic resin powder described in the second invention together with the raw rubber and other materials cannot be put into practical use because it shrinks with time or is affected by the solvent in the ink. There were drawbacks. Furthermore, when a thermosetting resin is used, it is difficult to control the reaction of the curing agent or the crosslinking agent, and the physical properties of the porous rubber are large, such as excessive curing with time, resulting in a decrease in spring properties. There was a downside.
Therefore, in order to simplify the manufacturing process when mixing raw rubber and other materials, it is sufficiently soft between the unvulcanized rubber mixture, and has sufficient hardness when made into a vulcanized porous rubber Printing materials were requested.

Japanese Utility Model Publication No. 31-002912 JP 50-000919 A

  Therefore, the present invention is easy to manufacture, and even if an excessive pressing force is applied to the penetrating stamp at the time of stamping, the stamped surface is not crushed, and the stamp ink stored is not excessively discharged. An object of the present invention is to provide a porous rubber stamping material having open cells that can be prevented from being consumed, can be clearly printed, can be prevented from wearing the marking surface, and has no deterioration in physical properties over a long period of time.

The porous rubber stamping material having open cells according to the first aspect of the invention made to solve the above-mentioned problem is a mixture of at least a raw rubber, an engineering plastic containing a benzene ring in the main chain, a water-soluble foam forming agent, and a vulcanizing agent. A porous rubber stamping material having open cells obtained by vulcanizing the master batch obtained and then removing the water-soluble foam-forming agent, wherein the engineering plastic containing a benzene ring in the main chain is polyarylate It is selected from resin, polyphenylene ether resin, modified polyphenylene ether resin, polysulfone resin, polyether sulfone resin, polycarbonate resin, and polybutylene terephthalate resin.
According to a second aspect of the present invention, the engineering plastic containing a benzene ring in the main chain is selected from polyarylate resin, polyphenylene ether resin, and modified polyphenylene ether resin. It is a quality rubber stamp.
The third invention is that the engineering plastic containing a benzene ring in the main chain has a particle size of 200 μm or less, and the usage ratio is 0.1 to 100 parts with respect to 100 parts of the raw rubber. A porous rubber stamp material having open cells according to the first or second aspect of the invention.

Since the hardness of the porous rubber could be improved by blending the specific engineering plastic with the raw rubber, the penetrating seal created using the porous rubber stamping material of the present invention has an excessive pressing force during the stamping. Even if it is added, the stamping surface is not crushed, it is possible to prevent consumption due to excessive outflow of the stored stamp ink, and the stamped print can be clearly printed without thickening or bleeding, and the hardness As a result, the wear of the stamp face could be prevented.
Also, the physical properties did not deteriorate due to shrinkage or curing of the porous rubber stamp material over time.
Further, since the unvulcanized rubber mixture is sufficiently soft, the manufacturing process when mixing the raw rubber and other materials is easy, and the manufacturing machine is not damaged.

The present invention will be described in detail below.
Examples of the raw rubber that can be used in the present invention include natural rubber (NR) or synthetic rubber having a molecular weight of about 20,000 to 1,000,000 (JIS K6300 Mooney viscosity center value = about 70 to 95). As the synthetic rubber, acrylonitrile-butadiene rubber (NBR), styrene-butadiene (SBR), chloroprene (CR), butadiene rubber (BR), polyurethane rubber (UR) and the like can be used. In particular, acrylonitrile-butadiene rubber (nitrile content: 30 to 50%) is excellent as oil resistance, aging resistance, elasticity and toughness, and is therefore optimal as a raw material for porous rubber stamps.

Next, in the present invention, it is essential to blend an engineering plastic containing a benzene ring in the main chain, polyarylate resin, polyphenylene ether resin, modified polyphenylene ether resin, polysulfone resin, polyether sulfone resin, Examples thereof include polycarbonate resin, polyethylene terephthalate resin, polybutylene terephthalate resin, and the like. Among them, polyarylate resin, polyphenylene ether resin, and modified polyphenylene ether resin are excellent in compatibility with raw material rubber, increase the hardness of porous rubber stamping material, maintain stable physical properties, and improve foamability. Therefore, it is preferably used. As polyarylate resin, U polymer U-100, P-1001, P-3001, P5001, U8000, U-8400H, AX-1500 (trade name: manufactured by Unitika Ltd.), as polyphenylene ether resin, PPO (product) Name: manufactured by General Electric Co., Ltd.), modified polyphenylene ether resins include Iupiace AN20 / AN30 / AN45 / AN60 / AN70 / AN80 / AN91 / AV20 / AV30 / AV40 / AN60 / AN70 / AN80 / AN90 / AH40 / AH50 / AH60 / AH70 / AH80 / AH90 (trade name: manufactured by Mitsubishi Engineering Plastics Co., Ltd.) can be exemplified. Among these, a combination in which an engineering plastic selected from a polyarylate resin, a polyphenylene ether resin, and a modified polyphenylene ether resin and an acrylonitrile-butadiene copolymer as a raw rubber are most preferable.
Engineering plastics containing a benzene ring in the main chain are thermoplastic polymers that are highly compatible with raw rubber and can improve the foamability while increasing the hardness of the porous rubber stamping material. . Further, since the unvulcanized rubber mixture is not cured when mixed with the raw rubber or other materials, the unvulcanized rubber mixture is sufficiently soft and facilitates the manufacturing process.
The engineering plastic containing a benzene ring in the main chain used in the present invention has a particle size of 200 μm or less, and preferably has a particle size of 0.1 to 60 μm. Those having a particle diameter exceeding 200 μm are not preferable because the compatibility is deteriorated.
Moreover, 0.1-100 parts are used with respect to 100 parts of raw material rubbers, and especially 1-40 parts are used preferably as a usage ratio of the engineering plastic which contains a benzene ring in the main chain. When the amount is too small, a sufficient effect cannot be obtained. When the amount is too large, rubber physical properties such as tensile strength are deteriorated.

Examples of the water-soluble foam-forming agent that can be used in the present invention include fine powders such as salts and sugars.
Examples of the water-soluble foam-forming agent that can be used in the present invention include fine powders such as salts and sugars.
The salt is an inorganic compound that is easily finely powdered, does not decompose and gasify at the rubber vulcanization temperature (110 ° C. to 160 ° C.), and can be easily removed by water after heating. Salts such as sodium sulfate and sodium nitrate are used. The diameter is usually 1 to 500 μm, and the use ratio is about 100 to 2000 parts, preferably 200 to 1500 parts, with respect to 100 parts of the raw rubber.
As the sugar, any of monosaccharides such as pentose and hexose, disaccharides such as saccharose and maltose, and polysaccharides such as starch and glycogen can be used, and these can be used in combination. The particle size is usually 1 to 500 μm. Among these, starch is excellent in solubility, and a powder having a uniform required particle diameter can be easily obtained, and is preferably used because it is inexpensive. The use ratio is about 10 to 300 parts, preferably 50 to 200 parts, with respect to 100 parts of the raw rubber. During vulcanization, these sugars swell under the influence of heat and generate a trace amount of moisture as a gas. This gas acts as a kind of foaming agent and gives a good result for bubble formation.
In the present invention, as the water-soluble foam-forming agent, 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 blending weight ratio of the salt and sugar is preferably about 9: 1 to 3: 1, particularly preferably 4: 1. In the present invention, the reason why the blending weight ratio of the salt and the sugar is in such a range is that if the amount of the sugar is too large, generation of moisture and carbon dioxide gas is increased during vulcanization, and these excessively create bubbles. This is because the bubbles of the porous rubber may become non-uniform, and the decomposition of the saccharide itself may proceed too much, making it impossible to mold the mixture in the mold. On the other hand, if the amount of sugar is too small, the sugar particles are not properly interposed between the salt particles, and the effect of the sugar cannot be sufficiently exhibited.

  Examples of the vulcanizing agent that can be used in the present invention include known vulcanizing agents such as precipitated sulfur, sulfur, selenium, tellurium, sulfur chloride, and the use ratio thereof is about 100 parts of the raw rubber. 1 to 30 parts can be used, with 2 to 10 parts being particularly preferred.

Furthermore, in the present invention, fillers, additives and the like which are usually used in rubber production can be used as necessary.
Examples of the filler that can be used in the present invention include known carbon black, silica, finely divided silicic acid, artificial silicate, calcium carbonate, and the like. It is preferable because it has a strong connection and a reinforcing action. The use ratio is about 10 to 100 parts with respect to 100 parts of the raw rubber, and the range of 40 to 70 parts is particularly preferable.
Additives that can be used in the present invention include amine-based anti-aging agents, softeners such as petroleum jelly and plasticizers, vulcanization aids such as zinc white, and guanidine-based vulcanization accelerators. can do.
An appropriate amount of organic synthetic fiber can also be added to adjust the rubber hardness. Organic synthetic fibers include polyethylene terephthalate fibers, polyacrylonitrile fibers, acrylic fibers, aliphatic polyamide fibers such as nylon 6, nylon 6/6, nylon 4/6, nylon 6/10, nylon 11, etc., polypropylene fibers, polyethylene Fiber, polyvinyl alcohol fiber, polyvinyl chloride fiber, polyvinylidene chloride fiber, polyurethane fiber, polyalkyl paraoxybenzoate fiber, polytetrafluoroethylene fiber, aramid fiber, wholly aromatic polyester fiber, poly-p-phenylenebenzobisthiazole fiber, Poly-p-phenylenebenzbisoxazole fiber, polybenzimidazole fiber, polyoxymethylene fiber, and the like can be used, and staples having a fiber length of 0.2 to 2 mm are used. Further, those organic synthetic fibers having a fineness of 0.1 to 100d are particularly preferably used.

Next, the manufacturing method of the porous rubber stamp material of this invention is demonstrated.
The raw materials are put into a kneader and kneaded to obtain a master batch. Next, an unvulcanized sheet is created with a calendar roll or the like. Next, the sheet-formed master batch is placed in a mold and heated and vulcanized at a temperature of about 80 ° C. to 160 ° C. for 10 minutes to 2 hours. A well-known thing can be used as a heating means. For example, electric heating or steam heating can be used. Next, it is taken out from the mold, and the water-soluble foam forming agent is washed while repeatedly compressing and expanding using cold water or hot water. Thus, the porous rubber stamping material having open cells of the present invention can be obtained.
The porous rubber stamping material of the present invention is used not only as a single layer, but also as an upper layer portion and / or a lower layer portion of a porous rubber stamping material comprising two layers of an upper layer portion (ink holding portion) and a lower layer portion (printing portion). can do. However, the water-soluble bubble forming agent for the upper layer is slightly larger than the water-soluble bubble forming agent for the lower layer. This is because the bubble diameter of the upper layer portion becomes larger than the bubble diameter of the lower layer portion, and when impregnated with ink, stable ink supply to the lower layer portion can be achieved by capillary action.
Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to these examples. “Parts” means parts by weight.

Example 1
100 parts of acrylonitrile-butadiene rubber, 5 parts of sulfur, 5 parts of zinc oxide, 5 parts of vulcanization accelerator, 30 parts of softener comprising petrolatum / DBP, 50 parts of carbon black, 2 parts of anti-aging agent, 100-200 μm chloride Add 800 parts of sodium, 200 parts of 50-150 μm starch and 20 parts of 0.1-60 μm polyarylate resin (poly 4,4′-isopropylidenediphenylene terephthalate / isophthalate copolymer) and knead to make a masterbatch This was a flat sheet having a thickness of 7 mm.
Next, the sheet was accommodated in a smooth mold, and then a pressure of about 200 kg / cm ² was applied to sandwich the sheet between hot plates and vulcanized at a temperature of 120 ° C. for 60 minutes. After vulcanization, the mold was released and washed sufficiently until sodium chloride and starch were completely removed, and this was dehydrated and dried to obtain a porous rubber stamp of this example.
Next, the porous rubber stamping material was engraved with a YAG laser processing machine, and then cut into a required size to obtain a permeation stamp.
When the oil-based pigment ink having a viscosity of 500 to 2000 mPa · S (20 ° C., 65%, 60 rpm) containing a castor oil derivative as a main solvent is occluded and printed, the ink occlusion amount is sufficient and excessive pressure is applied. Even when the mark is added, the printing surface is not crushed, and the ink can be prevented from excessively flowing out, and can be printed clearly over a long period of time without becoming thick or bleeding. In addition, the ink ejection property was good and clear marking without fading could be performed over a long period of time. In addition, the wear of the stamp face could be prevented by improving the hardness. Further, the physical properties of the penetrating stamp did not deteriorate with time, and the spring property did not deteriorate or became brittle, and the stamp surface was not damaged.

(Example 2)
100 parts of acrylonitrile-butadiene rubber, 5 parts of sulfur, 5 parts of zinc oxide, 5 parts of vulcanization accelerator, 30 parts of softener comprising petrolatum / DBP, 50 parts of carbon black, 2 parts of anti-aging agent, 100-200 μm chloride 800 parts of sodium, 100 parts of 50-150 μm starch, 100 parts of 10-100 μm saccharose, and 20 parts of polyphenylene ether resin modified with 0.1-60 μm high impact polystyrene are added and kneaded to form a master batch. It was set as the flat sheet of thickness 7mm.
Next, the sheet was accommodated in a smooth mold, and then a pressure of about 200 kg / cm ² was applied to sandwich the sheet between hot plates and vulcanized at a temperature of 120 ° C. for 60 minutes. After vulcanization, the mold was released and washed sufficiently until sodium chloride, starch and saccharose were completely removed, and this was dehydrated and dried to obtain a porous rubber stamping material of this example.
Next, the porous rubber stamping material was engraved with a YAG laser processing machine, and then cut into a required size to obtain a permeation stamp.
When the oil-based pigment ink having a viscosity of 500 to 2000 mPa · S (20 ° C., 65%, 60 rpm) containing a castor oil derivative as a main solvent is occluded and printed, the ink occlusion amount is sufficient and excessive pressure is applied. Even when the mark is added, the printing surface is not crushed, and the ink can be prevented from excessively flowing out, and can be printed clearly over a long period of time without becoming thick or bleeding. In addition, the ink ejection property was good and clear marking without fading could be performed over a long period of time. In addition, the wear of the stamp face could be prevented by improving the hardness. Further, the physical properties of the penetrating stamp did not deteriorate with time, and the spring property did not deteriorate or became brittle, and the stamp surface was not damaged.

(Example 3)
100 parts of acrylonitrile-butadiene rubber, 5 parts of sulfur, 5 parts of zinc oxide, 5 parts of vulcanization accelerator, 30 parts of softener comprising petrolatum / DBP, 50 parts of carbon black, 2 parts of anti-aging agent, 100-200 μm chloride 400 parts of sodium, 100 parts of 50 to 150 μm starch, 100 parts of 10 to 100 μm saccharose and 20 parts of 0.1 to 60 μm polyphenylene ether resin were added and kneaded to make master batch A, which was a 2 mm thick flat plate A sheet A was obtained.
Separately, 100 parts of acrylonitrile-butadiene rubber, 5 parts of sulfur, 5 parts of zinc oxide, 5 parts of vulcanization accelerator, 30 parts of softener comprising petrolatum / DBP, 50 parts of carbon black, 2 parts of anti-aging agent, 800 parts of sodium chloride of 150 to 500 μm, 100 parts of starch of 50 to 150 μm, and 100 parts of sucrose of 10 to 100 μm were added and kneaded to prepare a master batch B, which was a flat sheet B having a thickness of 5 mm.
Next, the sheet B is overlaid on the sheet A and accommodated in a smooth mold, and then a pressure of about 200 kg / cm ² is applied to sandwich it between the heating plates, and the sheet is heated at 120 ° C. for 60 minutes. Sulfurated. After the vulcanization, the mold is released, washed thoroughly until sodium chloride, starch and saccharose are completely removed, dehydrated and dried, and the porous material of this embodiment in which the ink holding part (sheet B) is integrated. A rubber stamp was obtained.
Next, after the sheet A and the sheet B are integrated into a single sheet, the porous rubber stamping material is engraved from the sheet A side with a carbon dioxide laser processing machine and then cut into a required size. Formed an ink holding part capable of occluding a large amount of ink, and a sheet A portion was able to obtain a penetrating mark on which a marking surface was formed.
When the oil-based pigment ink having a viscosity of 500 to 2000 mPa · S (20 ° C., 65%, 60 rpm) containing a castor oil derivative as a main solvent is occluded and printed, the ink occlusion amount is sufficient and excessive pressure is applied. Even when the mark is added, the printing surface is not crushed, and the ink can be prevented from excessively flowing out, and can be printed clearly over a long period of time without becoming thick or bleeding. In addition, the ink ejection property was good and clear marking without fading could be performed over a long period of time. In addition, the wear of the stamp face could be prevented by improving the hardness. Further, the physical properties of the penetrating stamp did not deteriorate with time, and the spring property did not deteriorate or became brittle, and the stamp surface was not damaged.

(Comparative Example 1)
A comparative example 1 prepared in exactly the same manner except that the polyarylate resin blended in Example 1 was changed to the same amount of silica was further processed to obtain a permeation mark.
(Comparative Example 2)
A modified polyphenylene ether resin blended in Example 2 was used in the same manner except that the same amount of silica was used, and this was further processed to obtain a permeation mark.
(Comparative Example 3)
A comparative example 3 prepared in exactly the same manner except that the polyphenylene ether resin blended in Example 3 was changed to the same amount of silica was further processed to obtain a permeation mark.

The test results are shown in the table below.
(hardness)
Spring hardness test Measured using a C-type hardness tester. In Example 3 and Comparative Example 3, the printing part side was measured.
(Shrinkage factor)
An oil pigment ink having a viscosity of 700 mPa · S (20 ° C., 65%, 60 rpm) using a castor oil derivative as a main solvent was occluded, and the shrinkage rate of the penetrating mark was measured.
(Stamp bleeding)
Assembling a penetrating mark with a viscosity of 700 mPa · S (20 ° C, 65%, 60 rpm) containing castor oil derivative as the main solvent into Xstamper name 9 (trade name: manufactured by Shiachihata Co., Ltd.) The imprint imprinted was observed.
(Continuous seal)
Assembled penetrants with a viscosity of 700 mPa · S (20 ° C, 65%, 60 rpm) containing castor oil derivative as the main solvent and assembled into Xstamper name 9 (trade name: manufactured by Shiachihata Co., Ltd.), 5000 times consecutively The imprint at the time of stamping was observed.

(Table 1)
┌───────┬┬────┬────┬────┬────┬┬────┬────┐
| | Example 1 | Example 2 | Example 3 | Comparative Example 1 | Comparative Example 2 | Comparative Example 3 |
├───────┼┼────┼────┼────┼────┼┼────┼────┤
│ Hardness │ 51 │ 55 │ 53 │ 45 │ 44 │ 44 │
├───────┼┼────┼────┼────┼────┼┼────┼────┤
│ Shrinkage │0-2% │0-2% │0-2% │3-4% │3-4% │3-4% │
├───────┼┼────┼────┼────┼────┼┼────┼────┤
│ Stamp bleeding │ No │ No │ No │ Yes │ Yes │ Yes │
├───────┼┼────┼────┼────┼────┼┼────┼────┤
│ Continuous imprintability │ Good │ Good │ Good │ Rub │ Rub │ Rub │
└───────┴┴────┴────┴────┴────┴┴────┴────┘

Claims (3)

Continuously obtained by vulcanizing a master batch obtained by kneading at least raw rubber, engineering plastics containing a benzene ring in the main chain, water-soluble foam former, and vulcanizing agent, and then removing the water-soluble foam former. A porous rubber stamp having air bubbles, and an engineering plastic containing a benzene ring in the main chain is a polyarylate resin, a polyphenylene ether resin, a modified polyphenylene ether resin, a polysulfone resin, a polyether sulfone resin, a polycarbonate resin, A porous rubber stamping material having open cells, which is selected from butylene terephthalate resins. 2. The porous rubber stamp material having open cells according to claim 1, wherein the engineering plastic containing a benzene ring in the main chain is selected from polyarylate resin, polyphenylene ether resin, and modified polyphenylene ether resin. The engineering plastic containing a benzene ring in the main chain has a particle size of 200 µm or less, and the use ratio thereof is 0.1 to 100 parts with respect to 100 parts of the raw rubber. A porous rubber stamping material having open cells according to Item 2.