JPH1067165A - Rubber printing body and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent mixing of colors even when a different ink is used for each printing part, and improve a labor environment and a hygienic environment in a manufacturing process. SOLUTION: A porous rubber 1 having continuous air bubbles and a non- porous rubber 2 are layered in one body, thereby to manufacture the rubber printing body. In this case, an adhesive 3 is applied onto a sheet of the non- porous rubber not vulcanized, onto which a sheet of the porous rubber not vulcanized and containing water-soluble fine particles is attached. The body is injected into a mold 4 and, valcanized and molded at 100-150 deg.C with 100-200kg/cm<2> . The water-soluble fine particles are cleaned out of the molded substance, whereby the porous rubber 1 of 0.1-1.0mm thickness is layered only at a surface of a printing part.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rubber print used for a stamp with a handle or a belt for a rotary rubber stamp.

[0002]

2. Description of the Related Art Conventionally, a porous rubber, which has been improved in ink transferability of a rubber stamp made of only a non-porous rubber, and has improved defects such as collapse of the imprint and stickiness, is laminated and integrated on the entire surface of the non-porous rubber. Rubber prints are known and are disclosed in JP-A-59-97065, JP-A-60-3060,
0-124249 and the like are disclosed. These rubber prints have a configuration in which a porous rubber having a thickness of about 0.1 to 0.5 mm is laminated not only on the non-porous rubber but also on the entire surface up to the non-printed portion on the non-porous rubber. As specified in the specification, the surface of an unvulcanized non-porous rubber sheet is coated with a readily soluble substance such as salts in a solvent such as toluene and a rubber substance obtained by melting unvulcanized rubber. Then, this is put into a mold and vulcanized and formed, and thereafter, a readily soluble substance is extracted to be prepared. However, in this manufacturing method, a large amount of a solvent such as toluene must be used in order to obtain a molten rubber substance, and mixing and stirring are performed for a long time to uniformly mix the easily soluble substance and the unvulcanized rubber. As a result, there was a problem in the working environment and hygiene related to odor. In addition, since the completed rubber printed body has a porous rubber layered on the entire surface, when a different color is applied to each printed portion, there is a disadvantage that color mixing occurs after a lapse of time.

[0003]

Accordingly, as a result of intensive studies, the present inventors have found a rubber printed body in which porous rubber is laminated only on the surface of the printed portion without using a molten rubber substance.

[0004]

SUMMARY OF THE INVENTION In a rubber printing body obtained by laminating and integrating a porous rubber having open cells and a non-porous rubber, only the surface of the printing portion has a porosity of 0.1 to 1.0 mm. A rubber printed body characterized by laminating rubber, and an unvulcanized porous material containing a water-soluble fine powder on which an adhesive is applied on an unvulcanized non-porous rubber sheet. Laminate a rubber sheet and put it in a mold.
The method for producing a rubber print, which is produced by vulcanizing at 100 to 150 ° C. and 100 to 200 kg / cm ² and washing the water-soluble fine powder from the molded material.

Hereinafter, the present invention will be described in detail. First, the raw materials used in the present invention will be described. Raw materials common to non-porous rubber and porous rubber include rubber, vulcanizing agents, fillers, additives, and the like. In addition, water-soluble fine powder is blended with porous rubber as a cell forming agent. The raw rubber of the present invention has a molecular weight of about 10,000 to 100,000 (JIS K
Natural rubber or synthetic rubber having a Mooney viscosity of 6300 (about 70 to 95) can be used. As the synthetic rubber, butadiene-styrene copolymer, butadiene-acrylonitrile copolymer, chloroprene, polyurethane rubber, ethylene-
Propylene-diene rubber and the like can be used. In particular, a butadiene-acrylonitrile copolymer (nitrile content of 31 to 31)
(42%) is excellent in oil resistance, aging resistance, elasticity and toughness, and is therefore most suitable as a material for a rubber print. As the vulcanizing agent usable in the present invention, sulfur, selenium,
Known vulcanizing agents such as tellurium and sulfur chloride can be used, and the use ratio thereof is about 2 to 30 parts per 100 parts of rubber. Examples of the filler that can be used in the present invention include known carbon black, finely divided silicic acid, artificial silicate, calcium carbonate, and the like. Particularly, carbon black is preferable because it has a strong bond with rubber and has a reinforcing effect. The usage ratio is about 40-6 for 100 parts of rubber.
0 parts, with a range of 45 to 55 parts being particularly preferred. When it is desired to obtain a white or chromatic printed body, silicic acid is preferably used. For example, nip seal VN3, nip seal LP, etc. (above, manufactured by Nippon Silica Industry Co., Ltd.), Leo seal (above, manufactured by Tokuyama Soda Co., Ltd.) and the like can be used. It is preferably used. Further, in the present invention, commonly used additives can be used. For example, anti-aging agents such as amines, softeners such as petrolatum, plasticizer, process oil,
Vulcanization aids such as stearic acid and zinc white, guanidines
An effective amount of a vulcanization accelerator such as thiazoles, tyriums, sulfenamides, dithiocarbamates and the like can be added.

Although not used for non-porous rubber, fine powders such as salts and sugars can be used as the water-soluble fine powder used for preparing the porous rubber. Salt is an inorganic compound that is easily pulverized, does not decompose into gas at the temperature of vulcanization of rubber (110 ° C. to 160 ° C.), and can be easily washed off with water after vulcanization. Are used such as sodium chloride, sodium sulfate and sodium nitrate. The diameter is usually 32 to 350 mesh (0.044
０．４0.498 mm), and the usage ratio is about 200 to 1200 parts with respect to 100 parts of rubber, and particularly preferably 400 to 600 parts. 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 further, these can be used in combination. The particle size is usually 150 mesh pass (0.010 to 0.103 mm). Among them, potato 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 to 300 parts for 100 parts of rubber,
Preferably it is 100 to 200 parts. During the vulcanization, these sugars are generated under the influence of heat as a trace of water contained therein. Then, this gas acts as a kind of blowing agent and gives good results for bubble formation. In the present invention, as the water-soluble fine powder, the salt and the sugar may be used alone or in combination, and may be appropriately selected depending on the use. When used together, the compounding weight ratio of salt and sugar is 9:
The ratio is preferably about 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 moldability during vulcanization deteriorates. On the other hand, if the amount of the 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.

Here, in the rubber printed body of the present invention, when the rubber hardness of the porous rubber is set so as to be not less than a spring hardness of 45 (measured value of a spring type hardness test C type hardness meter), it is particularly excellent. A rubber printed body was obtained, and chipping of the porous rubber and blurring of the imprint did not occur.

Next, the manufacturing method of the present invention will be described. Each of the above components is kneaded by a kneading rubber roller, and is sheeted out by a calender roll to prepare an unvulcanized rubber sheet. Here, a non-porous rubber sheet containing no water-soluble fine powder is a non-porous rubber sheet, and a porous rubber sheet containing no water-soluble fine powder is used. The thickness of the unvulcanized porous rubber sheet is set to about 0.1 to 1.0 mm so that the thickness of the porous rubber after vulcanization is 0.1 to 1.0 mm. Next, an adhesive such as methyl ethyl ketone or rubber glue is applied to the non-porous rubber sheet, and the porous rubber sheet is adhered thereon, and this is placed in a mold. Next, at 100 to 150 ° C and 100 to 200 kg / cm ² ,
After vulcanization for about 10 to 10 minutes, a porous rubber is left only in the printed portion, and a substance free of the porous rubber is left in the non-printed portion. Next, when the water-soluble fine powder is washed away from the material after molding, a rubber print body in which a porous rubber having open cells with a thickness of 0.1 to 1.0 mm is laminated only on the surface of the print portion is obtained. it can. In addition, after laminating non-porous rubber sheet and porous rubber sheet, plant-based natural fiber such as cotton, silk, rayon, nylon, polyester, acrylic, etc., animal-based natural fiber, regenerated fiber, semi-synthetic fiber, synthetic When the base fabric consisting of fibers and their combination is superposed and vulcanized and formed, and both ends of the formed material are bonded,
An endless belt rubber print for rotating rubber stamps can be created. When manufacturing the present invention, the step of bonding with the above-mentioned adhesive is omitted, and when the porous rubber sheet is directly placed on the non-porous rubber sheet and vulcanized and molded, the porous rubber at the tip of the printing portion is torn. As a result (see FIG. 3), the porous rubber cannot be laminated only on the printed portion as in the present invention.

[0009]

The reason why the porous rubber layer is formed only on the print portion surface is unknown, but is presumed to be as follows. It is thought that the water-soluble fine powder was blended, but the unvulcanized porous rubber of the present invention is easily softened by heat as compared with the non-porous rubber. Therefore, at the moment when the mold touches, it seems that the porous rubber is in a state where it easily flows due to the heat while the non-porous rubber is in a state where it does not easily flow (see FIG. 4). ).
When pressure is applied thereto, the portion of the porous rubber that is in contact with the mold tends to escape to the portion that is not in contact with the mold (printed portion forming recess) (see FIG. 5). Furthermore, when pressure is applied, the porous rubber that first comes into contact with the mold completely shifts to the printing portion forming recess, and at the same time, the non-porous rubber enters the printing portion forming recess and forms the printing portion. (See FIG. 6).
When pressure is further applied and vulcanization is performed for a certain period of time, a rubber print body in which porous rubber is thinly laminated only on the surface of the print portion can be produced (see FIG. 7). Since the rubber prints thus obtained have independent print portions, different colors can be applied to each print portion without causing color mixing.

Now, the present invention will be described in further detail with reference to Examples. However, the present invention is not limited by these examples. (Example 1) 100 parts of synthetic rubber (NBR), 5 parts of sulfur,
5 parts of zinc white, 5 parts of vulcanization accelerator, liquid rubber (low polymerization NB
R) 30 parts of a softening agent composed of Vaseline / DBP, 50 parts of silicic acid, 2 parts of an antioxidant, 200-350 mesh (0.044-0.074 mm) sodium chloride 70
0 parts, 150-250 mesh (0.062-0.10
A raw material composed of 30 parts each of fine powder of potato starch and fine powder of saccharose (3 mm) was kneaded well, and this was sheeted out to a thickness of 0.8 mm to obtain a porous rubber sheet. Separately, synthetic rubber (NBR) 100
Parts, 5 parts of sulfur, 5 parts of zinc white, 5 parts of vulcanization accelerator, 30 parts of softener composed of liquid rubber (low-polymerized NBR), petrolatum, DBP, etc., 50 parts of silicic acid, and 2 parts of antioxidant Was kneaded well, and this was sheeted out to a thickness of 3.0 mm to obtain a non-porous rubber sheet. Next, methyl ethyl ketone was slightly applied on the non-porous rubber sheet, and the porous rubber sheet was adhered to the non-porous rubber sheet. Then 15
Vulcanization molding was performed at a temperature of 150 ° C. for 10 minutes while applying a pressure of 0 kg / cm ² . Thereafter, it was released from the mold, washed thoroughly with water until the water-soluble fine powder was completely washed out, and then dehydrated and dried to obtain a rubber print having a thickness of 0.8 mm of porous rubber.
Since no porous rubber is present in the non-printed portion of the rubber printed body obtained in this way, color mixing does not occur even if different inks are applied to each printed portion and used. . (Example 2) 100 parts of synthetic rubber (NBR), 5 parts of sulfur,
5 parts of zinc white, 5 parts of vulcanization accelerator, liquid rubber (low polymerization NB
R) 30 parts of a softening agent composed of Vaseline / DBP, 50 parts of silicic acid, 2 parts of an antioxidant, 200-350 mesh (0.044-0.074 mm) sodium chloride 70
0 parts, 150-250 mesh (0.062-0.10
A raw material comprising 30 parts each of fine powder of potato starch and fine powder of saccharose (3 mm) was kneaded well, and this was sheeted out to a thickness of 0.5 mm to obtain a porous rubber sheet. Separately, synthetic rubber (NBR) 100
Parts, 5 parts of sulfur, 5 parts of zinc white, 5 parts of vulcanization accelerator, 30 parts of softener composed of liquid rubber (low-polymerized NBR), petrolatum, DBP, etc., 50 parts of silicic acid, and 2 parts of antioxidant Was kneaded well, and this was sheeted out to a thickness of 1.5 mm to obtain a non-porous rubber sheet. Next, methyl ethyl ketone was lightly applied on the non-porous rubber sheet, and the porous rubber sheet was stuck. After that, the 30th rayon yarn was 100 / inch and the 30th polyester yarn was 6
It was placed on a plain cloth woven at 0 / inch, and housed in a mold having a 1 mm printed portion forming recess on the inner bottom surface. Then, at 150 ° C. while applying a pressure of 150 kg / cm ^2.
At a temperature of 10 minutes. After vulcanization, mold release until sodium chloride and starch are completely washed away.
It was thoroughly washed with water and dehydrated and dried. Next, an unvulcanized rubber dissolved in a rubber solvent is applied to an adhesive portion formed by peeling off one end of the molded material, and then vulcanized and adhered to the adhesive portion at the other end to obtain an endless annular body, This was cut into a required width to obtain an endless belt rubber print of 0.5 mm in thickness of porous rubber. Since the porous rubber does not exist at all in the non-printed part of the endless belt rubber printed body obtained in this manner, color mixing may occur even if different inks are applied to each printed part and used. There is no.

[0011]

[Effect] 0.1-1.
Since a 0-mm porous rubber is laminated, color mixing does not occur even if different inks are applied to the respective printed portions and used. Also, since it is not necessary to use a solvent such as toluene to dissolve and disperse the easily soluble substance and the unvulcanized rubber, it is not necessary to be in contact with the organic solvent for a long time in the manufacturing process, and it is possible to improve the working environment and hygiene. The environment has improved.

[Brief description of the drawings]

FIG. 1 is a sectional view of the present invention.

FIG. 2 is a cross-sectional view of a conventional rubber print.

FIG. 3 is a cross-sectional view of a rubber print body manufactured without a step of bonding with an adhesive.

FIG. 4 is a manufacturing process A of the present invention.

FIG. 5 is a manufacturing process B of the present invention.

FIG. 6 is a manufacturing process C of the present invention.

FIG. 7 is a manufacturing process D of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Porous rubber 2 Non-porous rubber 3 Adhesive 4 Die 5 Printing part forming recess

Claims (2)

[Claims] In a rubber printing body obtained by laminating and integrating a porous rubber having open cells and a non-porous rubber, a porous rubber having a thickness of 0.1 to 1.0 mm is laminated only on the surface of a printing portion. A rubber printed body characterized in that: 2. An adhesive is applied onto an unvulcanized non-porous rubber sheet to produce a rubber printed body obtained by laminating and integrating a porous rubber having open cells and a non-porous rubber. An unvulcanized porous rubber sheet containing a water-soluble fine powder is adhered to a mold, which is put into a mold and
By vulcanizing and molding at 100 to 200 kg / cm ² at a temperature of 150 to 150 ° C. and washing the water-soluble fine powder from the material after the molding, a thickness of 0.1 to 1.0 mm is formed only on the surface of the printing portion. A method for producing a rubber print body in which a porous rubber is laminated.