JP2005042406A - Method of manufacturing elastic column - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an elastic column inexpensively manufacturable at a quick delivery. <P>SOLUTION: An external facing body is formed by winding and covering the outside with thin tape-like unvulcanized rubber by winding and covering the periphery of a core body with a cushioning material composed of the unvulcanized rubber mixed with short fiber. A vulcanizing molding time is shortened by heating and molding these in a short time during which at least the external facing body is vulcanized and molded. In this case, the intermediate cushioning material is put in an unvulcanized state, and since the short fiber is mixed with the unvulcanized rubber, a flow of the rubber is restrained when external facing rubber is vulcanized, the foaming restraining effect by half-heating is exhibited, and deformation by being naturally left as it is can be restrained. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

 The present invention relates to an elastic column used for marking a separation line between upper and lower roadways or a boundary line between a roadway and a sidewalk, and other markings such as parks and streets, and a method for manufacturing the same.

Even when this type of elastic column collides as a sign such as a partition, it is required to quickly restore the colliding object without causing harm to the elastic column itself. Patent Document 1 includes an exterior body, a rigid core pillar that is housed in the center of the exterior body, a foamed elastic material and an exterior body holder filled between them, and a pedestrian or the like may collide accidentally. An elastic column formed by filling a shock absorbing cushioning material that suppresses the vehicle's entry effectively by using a rigid core column to minimize damage when the vehicle is simply in contact Is disclosed.
JP 2000-282428 (see paragraph 0061)

    By the way, in the elastic column as shown in Patent Document 1, when the exterior body and the intermediate cushioning material are made of rubber, it is advantageous in that the durability becomes very high under conditions where a sudden and large load or impact force is applied. However, since the intermediate cushioning material is thick, it takes a long time for vulcanization molding, which increases the production cost and also makes it difficult to meet short delivery times.

  In view of the above, an object of the present invention is to provide an elastic column that can be delivered quickly and can be manufactured at low cost, and a method for manufacturing the same.

 As a result of intensive research conducted by the present inventors in order to achieve the above object, when both an exterior body that exhibits a shock-absorbing shock absorbing function and an intermediate shock absorbing material are made of rubber, a place where rubber characteristics are inherently necessary Is only the exterior body, and the intermediate buffer material only needs to exhibit the function of joining the core body and the exterior body and the deformation following performance, and is not necessarily vulcanized rubber. For this reason, the intermediate cushioning material may be used in an unvulcanized state. However, when the cushioning material is in an unvulcanized state, foaming occurs due to mid-heating when the rubber of the exterior body is vulcanized, resulting in a decrease in durability. In addition, there is a problem that the permanent set is large at the time of deformation, and further, the material is deformed by being left alone.

 Therefore, the present invention has been solved by mixing short fibers with unvulcanized rubber and arranging them in the circumferential direction of the elastic column. That is, the present invention is a method of manufacturing an elastic column comprising an exterior body, a core body provided in the center of the exterior body, and a shock absorbing cushioning material filled between the core body and the exterior body. A buffer material made of unvulcanized rubber mixed with short fibers is coated around the core body, and a thin-walled exterior body made of unvulcanized rubber is further coated on the outside, and at least these are coated with the exterior body. Is characterized by being heat-molded in a short time that can be vulcanized.

 According to the said structure, since the vulcanization time of a thin-walled exterior body may be short, a vulcanization molding time is shortened and it can respond to a short delivery date. At this time, although the intermediate cushioning material is in an unvulcanized state, since short fibers are mixed in the unvulcanized rubber, the rubber flow is suppressed during rubber vulcanization of the exterior body, and also due to midway heating. Demonstrates the effect of suppressing foaming and can suppress deformation due to natural standing.

 In particular, when the unvulcanized rubber mixed with short fibers used for the cushioning material is wound around the core while being extruded in a tape form from an extruder, the short fibers are oriented in the longitudinal direction of the tape as the unvulcanized rubber is extruded. Therefore, it is not necessary to take a special arrangement method in the circumferential direction, and problems due to the unvulcanized state of the buffer material can be solved.

 Here, the short fiber is a short cotton-like fiber (staple) having a length of about 30 mm to 100 mm. This short fiber acts as a binder for the unvulcanized rubber due to its characteristics such as fuzzing, and can suppress the flow of rubber. The material of the short fiber is not particularly limited, but from the viewpoint of reinforcing the unvulcanized rubber, a fiber having high strength and small elongation such as an aramid fiber is preferable.

 It was found that the mixing ratio of the short fibers to the unvulcanized rubber is preferably 1 to 20 parts by weight with respect to 100 parts by weight of the unvulcanized rubber, and more preferably 1 to 5 parts by weight. When the amount exceeds 20 parts by weight, there is a problem that the orientation at the time of extrusion is lost, and even a slight blending of about 1 part by weight is effective in suppressing rubber flow.

 Further, as the exterior body, a rubber-like elastic body is used in order to provide durability when a sudden and large load or impact force is applied. As this rubber component, various soft rubbers such as NR, EPDM, or blended rubber thereof can be used. The exterior body can be molded by vulcanizing and molding an unvulcanized rubber. The form of the unvulcanized rubber at this time is not particularly limited, such as a sheet shape, a cylindrical shape, or a tape shape, but a method of wrapping and covering the tape-shaped unvulcanized rubber around the buffer material may be adopted. Thus, it is possible to easily deal with orders for elastic columns having various outer diameters.

 Here, heat molding in a short time during which the exterior body can be vulcanized and molded means a time shorter than the time during which vulcanization molding is possible including the intermediate buffer material, and at least the time during which the exterior body can be vulcanized and molded. As the minimum time, and a more preferable embodiment, it means the time during which the outer portion of the exterior body and the intermediate cushioning material in contact with the exterior body are vulcanized. This time is not constant depending on the rubber material and wall thickness of the outer package, but normally, when the time required for the entire vulcanization requires 90 minutes at a heating temperature of 150 ° C., the heating time of about 15 minutes at the same temperature. It can be illustrated.

 Moreover, a thin-walled outer body indicates that the wall thickness is thinner than that of an intermediate cushioning material. Specifically, a thickness of 2 mm to 3 mm that can prevent damage at the time of impact can be exemplified.

 As is apparent from the above description, according to the present invention, a thin-walled exterior body made of unvulcanized rubber is coated on the outside with a buffer material made of unvulcanized rubber mixed with short fibers around the core body. Since these are heat-molded in a short time in which at least the exterior body can be vulcanized, the vulcanization molding time can be shortened and the short delivery time can be accommodated. At this time, although the intermediate cushioning material is in an unvulcanized state, since short fibers are mixed in the unvulcanized rubber, the rubber flow is suppressed during rubber vulcanization of the exterior body, and also due to midway heating. Demonstrates the effect of suppressing foaming and can suppress deformation due to natural standing.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view showing an installed state of an elastic column showing an embodiment of the present invention.

  As shown in the drawing, the elastic column 1 of the present embodiment includes a cylindrical bag-shaped exterior body 2, a core body 3 installed in the center portion thereof, and an impact filled between the exterior body 2 and the core body 3. And a buffer material 4 for absorption.

 The exterior body 2 is formed in a cylindrical bag shape from a dome-shaped or hemispherical cap portion 2a at the tip and a cylindrical body portion 2b continuous to the lower end portion of the cap portion. And it forms in a long thing about 20 to 80 cm in length with an outer diameter of about 130 mm so that it may function as a sign for a partition. As the material of the outer package 2, soft EPDM and NR blend rubber is used, and its hardness is 40 to 60 in terms of JISA hardness, and brown rubber is used. Furthermore, the thickness of the exterior body 2 is set to a thin thickness of about 2 mm to 3 mm so as to prevent damage at the time of impact and to form an uneven pattern on the surface.

 As shown in FIG. 2, the exterior body 2 is molded by wrapping a tape-like unvulcanized rubber 2c around the buffer material 4 to form a body portion 2b, and then a tip cap made of unvulcanized rubber. The part 2a is joined to the tip of the body part 2b to form a cylindrical bag, and these are vulcanized to form. In addition, shaping | molding of an exterior body is not restricted to this, After vulcanizing the trunk | drum 2b, you may attach the vulcanized front-end | tip cap part 2a, and may shape | mold in a cylindrical bag shape.

 The core body 3 is made of a long rod-like or tubular synthetic resin material that exhibits a large bending allowance, and is capable of absorbing a large impact energy by bending when the vehicle collides. The diameter of the core body 3 is selected in accordance with the required strength and resilience. For example, a water pipe polyethylene pipe 75A (inner diameter 71.7 mm, outer diameter 89 mm) can be used. The length of the core 3 can be a length that can be embedded and fixed in the ground, for example, about 80 cm.

 The core body 3 is not limited to the synthetic resin tube, and can be configured by a metal cylinder or a combination of a metal cylinder and a coil. Moreover, although the core 3 is kept hollow, you may fill the hollow part with the buffer material 4 by the length of the underground exposure part from the front-end | tip.

 The shock absorbing shock absorbing material 4 is filled in the space between the core body 3 and the exterior body 2. The intermediate cushioning material 4 is obtained by wrapping and covering the core body 3 while extruding the unvulcanized rubber 4b mixed with the short fibers 4a from the extruder 11 (see FIG. 2) in a tape shape, and the elastic column 1 is short. Since it is vulcanized over time, it is commercialized in an unvulcanized state.

 Various rubbers such as NR, NBR, SBR, EPDM, and BR can be used as the unvulcanized rubber 4b forming the buffer material 4, and a blend of various rubber components may be used. Further, the thickness of the unvulcanized rubber 4b when extruded into a tape shape is not particularly limited, and can be appropriately selected according to required characteristics. In the present embodiment, tape-shaped unvulcanized rubber having a thickness of about 19 mm is used.

 Further, the extruded shape of the unvulcanized rubber 4b is not particularly required to be accurate, and it is only necessary to ensure an approximate outer shape. Therefore, non-standard rubber generated frequently in rubber factories can be used. Of course, rubber that has been pre-cured (burned) can also be used. Further, recycled rubber mixed with rubber chips collected from used products can also be used.

 The short fibers 4a mixed in the unvulcanized rubber are aramid fibers having a length of about 30 mm to 100 mm, and 1 to 5 parts by weight are blended with 100 parts by weight of the unvulcanized rubber.

 FIG. 2 is a process diagram showing the manufacturing process of the elastic column. As shown in FIG. 2, the elastic column is manufactured by fixing the core 3 to the mandrel 10, while rotating the mandrel 10, and rotating the unvulcanized rubber 4 b mixed with the short fibers 4 a into the die 11 a of the extruder 11. Then, it is extruded into a tape shape and wound around the core body 3 to form the cushioning material 4.

 Further, the body 2b of the exterior body 2 is formed by wrapping and covering a tape-like unvulcanized rubber 2c around the outside of the cushioning material 4. Thereafter, the tip cap portion 2a made of unvulcanized rubber is joined to the tip of the body portion 2b to form a cylindrical bag shape, which is inserted into the cavity of the molding die 12, so that at least the exterior body 2 can be vulcanized. The elastic column 1 is obtained by heat-molding in a short time (15 minutes at 150 ° C.) and pulling out the mandrel 10 after vulcanization molding.

 In this manufacturing process, when the cushioning material 4 is wound, the short fibers 4a are oriented in the longitudinal direction of the tape together with the extrusion of the unvulcanized rubber 4b, and eventually the short fibers 4a are oriented in the circumferential direction of the core body 3. In the range of 5% to 10% of the deformation strain, a displacement reaction force equivalent to that of the vulcanized rubber can be obtained, so there is no need for vulcanization. Further, the exterior body 2 requires vulcanization, but at this time, the buffer material 4 of the intermediate layer is heated in the middle, and does not cause the foaming phenomenon seen in the middle of heating in normal rubber. This is because the short fibers 4a suppress or disperse the phenomenon. Accordingly, the product vulcanization is changed from a heating condition of 150 ° C. for 90 minutes required for a general vulcanization to a heating condition of 15 minutes at 150 ° C., and the productivity can be greatly improved.

  Further, by disposing unvulcanized rubber as the buffer material 4 serving as an intermediate layer, there is concern about separation between the respective layers, but the buffer material 4 and the exterior body 2 are vulcanized and bonded at the interface. ,there is no problem. The buffer material 4 and the core body 3 do not need a large joining force from the beginning, but are sufficient due to the shrinkage of the expanded rubber due to the temperature during extrusion and the temperature during vulcanization, and the heat shrinkage of the short fibers themselves. The joint tightening force worked, and no separation of each part was observed even in repeated bending.

 Furthermore, as an effect of using unvulcanized rubber as the buffer material 4, followability to large deformation can be mentioned. This is because the vulcanized rubber has a breaking elongation of about 300%, whereas the unvulcanized rubber exhibits a breaking elongation of 700%.

 In addition, when the cushioning material 4 is commercialized in an unvulcanized state, there is a concern that natural deformation during use may occur, but actually, the cushioning material 4 has the core 3 and the exterior body 2 inside and outside. This is not a problem because the short fibers are arranged in the circumferential direction to prevent deformation in the unvulcanized rubber.

Sectional drawing which shows the installation state of the elastic column which shows one Embodiment of this invention Process chart showing the manufacturing process of elastic columns

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Elastic pillar 2 Exterior body 2a Cap part 2b Trunk part 2c Tape-like unvulcanized rubber 3 Core body 4 Buffer material 4a Short fiber 4b Tape-like unvulcanized rubber 10 Mandrel 11 Extruder

Claims (9)

A method of manufacturing an elastic column comprising an exterior body, a core body provided in a central portion of the exterior body, and a shock absorbing cushioning material filled between the core body and the exterior body,
A buffer material made of unvulcanized rubber mixed with short fibers is coated around the core body, and a thin-walled exterior body made of unvulcanized rubber is further coated on the outside, and at least the exterior body is vulcanized. A method for producing an elastic column, characterized by heat-molding in a short time for molding. 2. The method for producing an elastic column according to claim 1, wherein the unvulcanized rubber mixed with short fibers used for the cushioning material is wound around and coated on the core while being extruded in a tape shape from an extruder. The method for producing an elastic column according to claim 1 or 2, wherein a mixing ratio of the short fibers is 1 to 5 parts by weight with respect to 100 parts by weight of unvulcanized rubber. 4. The method for producing an elastic column according to claim 1, wherein the short fibers are aramid fibers. The unvulcanized rubber used for the exterior body is formed in a tape shape, and the tape-shaped unvulcanized rubber is wound around and covered around the cushioning material. Method. The method for producing an elastic column according to claim 1, wherein the core is a thermoplastic resin. An exterior body made of vulcanized rubber, a core body provided in the center of the exterior body, and a shock absorbing cushioning material made of a rubber component filled between the core body and the exterior body,
An elastic column, wherein the cushioning material is mixed with short fibers arranged in the outer circumferential direction of the core. The elastic column according to claim 7, wherein the cushioning material is molded in an unvulcanized state. The elastic column according to claim 7 or 8, wherein a mixing ratio of the short fibers is 1 to 5 parts by weight with respect to 100 parts by weight of a rubber component constituting the buffer material.

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