JP2006009180A - Organic fiber cord for reinforcing rubber article and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an organic fiber cord for reinforcing rubber articles, capable of preventing catching in a connection part when passing through an inserter and preventing occurrence of breaking of filaments arising from the connection part by suppressing increase of cord cross section in the connection part and to provide a method for producing the organic fiber cord. <P>SOLUTION: The organic fiber cord for reinforcing rubber articles is obtained by twisting two multifilaments and has the connection part 2A. In the organic fiber cord, the connection end part 3 of multifilament in the connection part 2A is formed in a tapered shape. The method for producing the organic fiber cord for reinforcing rubber articles comprises a step for mutually connecting an organic fiber cord in which two multifilaments are twisted to each other at the ends. In the production method, the connected end parts of the multifilament are formed in a tapered shape and the end parts formed in the tapered shaped are together joined. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  TECHNICAL FIELD The present invention relates to an organic fiber cord for reinforcing rubber articles (hereinafter also simply referred to as “reinforcing cord”) and a method for producing the same, and more specifically, an organic fiber cord for reinforcing rubber articles used as a reinforcing material for rubber articles such as tires. And a manufacturing method thereof.

  In various rubber products such as pneumatic tires, conveyor belts and hoses, reinforcing cords using organic fibers (textiles) or metal fibers are used as reinforcing materials. Among these, as the organic fiber cord, generally, a twisted cord formed by twisting a multifilament that is an aggregate of a plurality of monofilaments and twisting two or three of them is used. When manufacturing the cable, the length may vary, and depending on the application, a very long twisted cord may be required. Therefore, in such a case, it is necessary to connect the organic fiber cords at the ends.

  Conventionally, as a general method for manually connecting organic fiber cords, sewing and connecting by an electric sewing machine has been performed. However, in this method, terminal yarns are generated at both ends of the sewing portion, and the device is stopped or the cord is cut. Sometimes there was a problem. Moreover, although the cord connection method using the apparatus called a notter is also known, work was inferior, for example, a long time was required for the work and a twisting work was further required after the connection.

On the other hand, in Patent Document 1, when connecting the ends of two wire assemblies formed by twisting a multifilament yarn, the ends are freely twisted back so that the yarns are separated from each other. Forming the ends, forming the same number of yarn joint pairs at the free ends of each wire assembly, twisting back at least some of the filaments in each joint pair, and joining the untwisted portions together Forming a joint area juxtaposed and offset in the axial direction, combining filaments of two yarns in each joint area, and twisting all the yarns in the same direction as the twist direction of the wire assembly A coupling method comprising the steps of: According to this connecting method, there is no generation of terminal yarns, the connecting time can be shortened, and the joining area serving as the connecting portion is dispersed in two places, so that the bulge of the connecting portion can be reduced. It is done.
Japanese Patent No. 3241377 (Claims)

  By the way, when the rubber coating is performed on the organic fiber cord using an extruder, the organic fiber cord is usually arranged through an inserter (hole) after being subjected to a dipping process to an adhesive, and the rubber coating. It is introduced into an extruder for carrying out. However, in the organic fiber cords connected by the conventional connecting method, the cross-sectional area at the connecting part is inevitably increased to about twice the original, so that the organic fiber cord 31 is inserted into the inserter as shown in FIG. In some cases, the connecting portion 32 is caught when passing through 30 and resistance is generated, thereby causing breakage of the filament.

  Like the connection method described in Patent Document 1, it is possible to reduce the cross-sectional area of the connection part to 1.5 times the original code cross-sectional area by dividing the connection part into two parts. The hole diameter cannot be made so large due to the necessity of fixing the cord position so that it does not move due to rubber pressure in the coating process, and is usually set to about 1.2 times the organic fiber cord diameter (see FIG. 3). . Accordingly, the cross-sectional area can only allow up to about 1.44 times the original cord diameter, and the connecting portion having a cross-sectional area of 1.5 times cannot prevent the disconnection problem.

  Therefore, the object of the present invention is to solve the above-mentioned problems of the prior art and suppress an increase in the cross-sectional area of the cord at the connecting portion, thereby preventing the connecting portion from being caught when passing the inserter. An object of the present invention is to provide an organic fiber cord for reinforcing rubber articles that can prevent the filaments from being disconnected, and a method for producing the same.

  In order to solve the above-mentioned problems, the present inventors have intensively studied and found that the above problems can be solved by prescribing the end shapes of the multifilaments connected to each other to complete the present invention. It came.

That is, the organic fiber cord for reinforcing rubber articles according to the present invention is an organic fiber cord for reinforcing rubber articles, in which two multifilaments are twisted and have a connecting portion.
The connecting end of the multifilament in the connecting portion is formed in a taper shape.

  In this invention, it is preferable that the taper angle of the said connection end part is 30-45 degrees with respect to the longitudinal direction of a cord. Further, the cross-sectional area of the connecting portion is preferably 1.2 times or less of the cross-sectional area of the cord. Furthermore, the multifilament is preferably composed of one or both of a polyamide fiber and a polyester fiber.

Moreover, the manufacturing method of the organic fiber cord for reinforcing rubber articles of the present invention includes an organic fiber cord for reinforcing rubber articles that includes a step of connecting organic fiber cords formed by twisting two multifilaments together at ends. In the manufacturing method,
The end portions to which the multifilaments are connected are formed in a taper shape, and the end portions formed in a taper shape are joined to each other. The joining of the end portions can be suitably performed by welding, for example.

  According to the present invention, the above configuration can suppress an increase in the cross-sectional area of the cord in the connecting portion, thereby resulting in the hooking in the connecting portion when passing through the inserter and the increase in the resistance of the connecting portion. It became possible to prevent the filament from being disconnected. Therefore, according to the present invention, it is possible to perform a process such as rubber coating with a high yield even when a reinforcing cord having a connecting portion is used.

Hereinafter, preferred embodiments of the present invention will be described in detail.
FIG. 1A is a schematic cross-sectional view of a connecting portion according to a preferred example of the organic fiber cord for reinforcing rubber articles of the present invention. The reinforcing cord 10 of the present invention is an organic fiber cord formed by twisting two multifilaments, and has a connecting portion 2A. As shown in the drawing, the connecting ends of the multifilaments 11a and 11c in the connecting portion 2A. The part 3 is characterized in that it is formed in a tapered shape.

  In the present invention, since the connecting end 3 is formed in a tapered shape, an increase in the cross-sectional area (BB cross section in the figure) in the connecting part 2A can be suppressed, and the cord cross-sectional area (A in the figure) can be suppressed. -A cross-section) and the cross-sectional area of the connecting portion 2A can be made equal, so that there is no change in the cross-sectional area of the cord along the longitudinal direction, and the hooked portion at the connecting portion when passing through the inserter has been a problem in the past Can be eliminated and the resistance can be reduced. Therefore, even if it is a cord which has a connection part, an inserter can be made to pass through without producing breakage of a filament, and it can contribute to the yield improvement of a rubber coating process.

  Here, in the example shown in FIG. 1A, the multifilaments 11a and 11c are connected in a state where the respective tapered portions are overlapped with each other to form the connecting portion 2A, but FIG. As shown in FIG. 5, it is possible to connect the multifilaments 11a and 11c in a state where they are overlapped with each other beyond the respective taper portions. As shown in the drawing, in this case, the cross-sectional area (C-C cross section in the drawing) of the connecting portion 2A 'is larger than the original code cross-sectional area (A-A cross section in FIG. 1A). However, considering the resistance when passing through the inserter, and including the variation of the connecting portion, an increase in the cross-sectional area up to 1.2 times the original code cross-sectional area can achieve the effect of the present invention. It is considered to be within an acceptable range. Note that the strength of the connecting portion 2A in which the tapered portions shown in FIG. 1A are overlapped is about ½ of the original cord strength and tends to be insufficient, but the tapered portion shown in FIG. In the case of the connecting portion 2A ′ superposed over the upper limit, the strength is slightly increased. Therefore, the degree of multifilament superposition is preferably determined in terms of the balance between the effect of reducing the cross-sectional area and ensuring the strength.

  In the present invention, if the multifilament connection end 3 is formed in a tapered shape, the effect of reducing the cross-sectional area can be obtained, and the taper angle α is not particularly limited. However, it can be set to about 30 to 45 ° with respect to the longitudinal direction of the cord. If the taper angle α is too small, it is difficult to process the connecting end 3. On the other hand, if the taper angle α is too large, the connecting portion protrudes, and there is a risk of being caught when passing through the inserter.

  FIGS. 2A and 2B are explanatory views of the manufacturing process of the reinforcing cord of the present invention. The two organic fiber cords 1A and 1B shown in the figure are formed by twisting two multifilaments 11a, 11b and 11c, 11d, respectively. As shown in FIG. 2 (a), in the present invention, the ends of these organic fiber cords 1A and 1B are twisted back, and the ends are joined to each other. FIG. 1 corresponds to a schematic diagram of the connecting portion 2A related to the multifilaments 11a, 11b, and 11c in FIG.

  In the manufacturing method of the present invention, when the ends of the organic fiber cords 1A and 1B are connected to each other, it is necessary to form the ends 3 to which the multifilaments 11a to 11d that have been twisted back are connected in a tapered shape. As a result, an increase in the cross-sectional area at the connecting portions 2A and 2B can be prevented. At this time, as shown in the figure, the connecting portions 2A and 2B are preferably formed at appropriate intervals in the longitudinal direction of the cord, thereby further suppressing an increase in cross-sectional area at the connecting portion.

  The method of forming the end portions of the multifilaments 11a to 11d in a tapered shape is not particularly limited, and for example, a method of cutting obliquely with a cutting machine can be used. Preferably, the end portions of the multifilaments 11a to 11d are cut at a taper angle in the preferred range.

  Thereafter, by joining the end portions 3 of the multifilaments 11a to 11d formed in a tapered shape, the organic fiber cords 1A and 1B can be connected as illustrated. The method for joining the end portions 3 is not particularly limited, but for example, a method such as welding using ultrasonic waves, high frequencies, vibrations, lasers, or the like can be suitably used. In particular, it is preferable to weld the end portions of the multifilaments 11a to 11d while forming the end portions in a tapered shape.

  Then, as shown in FIG. 2B, the reinforcing cord 10 of the present invention can be obtained by twisting the connected multifilaments 11a and 11c and the multifilaments 11b and 11d again. As shown in the figure, the connecting portions 2A and 2B in the reinforcing cord 10 have a cross-sectional area substantially equal to that of the original organic fiber cords 1A and 1B.

  As the multifilament used in the present invention, organic filament multifilament yarns having a predetermined denier, for example, 840D, 1000D, 1260D, and 1890D yarns can be used. For example, cords of 840D / 2, 1000D / 2, 1260D / 2, and 1890D / 2 can be used. Examples of the multifilament yarn include nylon fiber, nylon 66, polyamide fiber such as Kevlar (aromatic polyamide), and polyester fiber yarn.

  Further, the reinforcing cord of the present invention can be suitably applied to, for example, a carcass as a reinforcing member of a pneumatic tire by coating a rubber through a dipping process. These dip process and rubber coating process may be carried out in accordance with conventional methods and are not particularly limited in the present invention. However, the present invention particularly aligns the reinforcing cords using an inserter in the rubber coating process. It is more effective when using a technique of introducing into an extruder and coating with rubber.

Hereinafter, the present invention will be described specifically by way of examples.
EXAMPLE Organic fiber cords 1A and 1B (material: polyester, denier: 1100 dtex / 2) formed by twisting two multifilaments 11a, 11b and 11c, 11d, respectively, as shown in FIG. Were connected to each other to produce a reinforcing cord having a connecting portion. Specifically, first, the end portions of the organic fiber cords 1A and 1B were twisted back, and the end portions 3 to which the multifilaments 11a to 11d were connected were tapered using a cutting machine. The taper angle α was 30 °. Next, the taper-shaped end portions 3 were bonded together by welding in a state where they were overlapped with each other as shown in FIG. The cross-sectional area (BB cross section in the figure) of the formed connecting portions 2A and 2B was substantially the same as the original code cross-sectional area (AA cross section in the figure).

Conventional Example Each of the two multifilaments 21a, 21b and 21c, 21d is twisted together, and the organic fiber cords 20A and 20B having the same material and the same denier as in the embodiment are formed at the ends as shown in FIG. Reinforcing cords having a connecting portion were produced by being connected to each other. Specifically, the end portions of the organic fiber cords 20A and 20B are twisted back, and the end portions 23 to which the multifilaments 21a to 21d are connected are overlapped with each other as shown in FIG. Then, bonding was performed. The cross-sectional area (cross-section bb in the figure) of the formed connecting portions 22A and 22B was approximately 1.5 times the original cross-sectional area of the cord (cross-section aa in the figure) (FIG. 4 (b). )).

  When the reinforcing cord 10 having the connecting portion obtained in the above embodiment is introduced into an extruder for performing rubber coating by aligning via an inserter after the dipping process, occurrence of catching in the connecting portions 2A and 2B is as follows. I was able to work smoothly. On the other hand, when the reinforcing cord obtained in the comparative example was subjected to the same process, the connecting portions 22A and 22B were caught when the inserter passed and the filament was broken.

(A), (b) is an expanded partial sectional view of the connection part of the organic fiber cord for rubber article reinforcement of the present invention. (A), (b) is explanatory drawing which shows the connection process of the organic fiber cord which concerns on this invention. It is explanatory drawing which shows the catching state of the connection part in an inserter. (A), (b) is explanatory drawing which shows the connection process of the conventional organic fiber cord.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1A, 1B Organic fiber cord 2A, 2B Connection part 3 Connection end part 11a-11d Multifilament 10 Organic fiber cord for rubber article reinforcement

Claims (6)

Two multifilaments are twisted together, and the organic fiber cord for reinforcing rubber articles having a connecting part,
An organic fiber cord for reinforcing rubber articles, wherein a connecting end portion of the multifilament in the connecting portion is formed in a taper shape.   The organic fiber cord for reinforcing rubber articles according to claim 1, wherein a taper angle of the connecting end portion is 30 to 45 ° with respect to a longitudinal direction of the cord.   The organic fiber cord for reinforcing rubber articles according to claim 1 or 2, wherein a cross-sectional area of the connecting portion is 1.2 times or less of a cross-sectional area of the cord.   The organic fiber cord for reinforcing rubber articles according to any one of claims 1 to 3, wherein the multifilament is composed of one or both of a polyamide fiber and a polyester fiber. In the method for producing an organic fiber cord for reinforcing rubber articles, comprising a step of connecting organic fiber cords formed by twisting two multifilaments together at the ends,
A method for producing an organic fiber cord for reinforcing rubber articles, wherein the end portions to which the multifilaments are connected are formed in a taper shape, and the end portions formed in a taper shape are joined to each other.   The manufacturing method according to claim 5, wherein the joining of the end portions is performed by welding.

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