JPH0796053A - String - Google Patents

Abstract

PURPOSE:To provide the string having excellent durability without impairing the ball fitting feel and repulsive property of the string by using a nylon resin having excellent wear resistance for the side yarn and resin coating layer of the string to be used for tennis, etc. CONSTITUTION:This string is formed by forming a side yarn layer 2 tightly and spirally wound with a side yarn consisting of plural pieces of monofilaments on the circumference of core yarn 1 consisting of a relatively bold monofilament and fixing this layer with an adhesive. The surface is provided with the resin coating layer 3 consisting of the 'nylon 46' resin to intensify fixing of the core yarn 1 and the side yarn layer 2 and to reform the surface. The 'nylon 46' resin used for the resin coating layer 3 is a crystalline polyamide obtd. by polycondensation of a 1, 4-diaminobutane and adipic acid, and its m.p. is 290 deg.C and is higher than the m.p. of most of the polyamide resins. In addition, this resin has extremely high wear resistance and, therefore, such 'nylon 46R' resin ms preferably used for the side yarn of the string as well.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a string used for badminton, tennis and the like.

[0002]

2. Description of the Related Art Conventionally, animal fibers such as sheep intestines have been used as strings. However, although the string made of animal fiber is excellent in shot feeling and resilience, it is expensive and inferior in durability. Therefore, strings made of synthetic fibers, which are cheaper and more durable than those of animal fibers, are often used. As a string made of synthetic fibers, a surface of synthetic fiber monofilament is coated with smooth oil or fat, or coated with a resin such as silicone, Teflon, or olefin, or a synthetic fiber monofilament is used as a core yarn and as a side yarn around the core yarn. A synthetic fiber monofilament is wound and a resin coating layer is further provided on the surface thereof.

As synthetic fibers constituting the strings, those made of polyamide resin and those made of polyester resin are mainly used. Among them, they are excellent in tensile strength, resilience, durability and workability. Polyamide resin used is often used. Further, a polyamide resin, which is excellent in durability and workability, is often used as a coating resin for strings. As the polyamide resin, a resin composed of nylon 6, nylon 66, nylon 6-10, nylon 6-12, or a copolymer resin of these resins is used, and nylon 6 is the best among these. Has been done. In recent years, the quality of strings made of synthetic fibers has been improved, and the shot feeling and the resilience have been considerably improved. However, players are demanding even greater durability.

As a measure for improving the durability, a smooth oil or fat is applied to the surface of the string, or a resin such as silicon, Teflon or olefin is coated, and fine particles such as carbon disulfide and molybdenum sulfide are mixed with these resins. And resin coating is applied. However, in the method of applying the smooth resin to the surface of the string, it is necessary to constantly apply the smooth resin because the smooth oil and fat is easily removed. The addition of a leveling agent to the resin also has the drawback of impairing the resin properties, so the amount added is limited. Therefore, under the present circumstances, the durability of the string has not been dramatically improved.

[0005]

In the above-mentioned method, the use of a synthetic fiber obtained by adding a durability improver to nylon 6 resin is the limit of the string having excellent durability. An object of the present invention is to provide a string with excellent durability.

[0006]

The present invention achieves the above object and has the following constitution. That is, according to the present invention, in a string having a side thread layer in which a plurality of side threads are wound around a core thread, and having a resin coating layer on the surface of the side thread layer, the resin coating layer is made of nylon 46 resin. The gist is a string that is characterized by
Further, the gist of the string is that the side yarn is a monofilament made of nylon 46 resin.

The present invention will be described in detail below. Figure 1
FIG. 1 is a cross-sectional view of a string showing an example of the present invention, in which a side yarn layer (2) in which side yarns made of a plurality of monofilaments are densely wound spirally around a core yarn (1) made of a relatively thick monofilament. ) Is formed and fixed with an adhesive. Further, a coating resin layer (3) made of nylon 46 resin is provided on the surface to strengthen fixation and surface modification of the core yarn (1) and the side yarn layer (2).

Durability, an important characteristic of the string,
It has resilience and shot feeling. Durability is evaluated by the usage time until the string is cut. The disconnection is caused by the string and wear and fatigue deterioration of the string due to the repeated impacts of the ball and the shuttlecock, resulting in a strong decrease in strength. The easiest way to improve durability is to thicken the string. Thick strings wear out and take a long time to be cut, which improves durability, but thick strings increase air resistance and slow the swinging of the racket by the player. Moreover, a thick string has a problem that the resilience and the shot feeling are deteriorated.

In the present invention, nylon 46 resin is used as the resin coating layer on the surface of the string. The nylon 46 resin used in the present invention is a crystalline polyamide obtained by polycondensing 1,4-diaminobutane and adipic acid, and can be used alone or by copolymerizing with other resins. Nylon 46 resin has a melting point of 290 ° C., which is the highest among polyamide resins, and has excellent abrasion resistance. The surface resin layer of the string of the present invention can be obtained by a coating process of a resin liquid in which a nylon 46 resin is dissolved in a solvent or a hot melt extrusion coating process.

It is also preferable to use nylon 46 resin as the side thread of the string. The side threads of the string can be wound in one layer or in two layers. For double-layer winding, use a slightly thinner side thread. The core yarn of the string of the present invention is a synthetic filament monofilament or multifilament bundle. The improvement in durability is greatly affected by the materials of the side threads and the surface resin layer. Therefore, there is no need to limit the material of the core thread, and there is no problem in using nylon 46 resin for the core thread.

[0011]

When nylon 46 resin is used for the surface resin layer and side threads of the string as in the present invention, nylon 46 resin is flexible, has a high melting point, and is excellent in wear resistance and heat resistance. It is possible to improve durability without damaging it.

[0012]

EXAMPLES Next, the present invention will be specifically described with reference to examples. In the example, the evaluation of the durability of the string is
The obtained string was attached to a hard tennis racket, a hard tennis ball was hit by an ordinary hitter, and the number of hits until the string was cut was measured.

Example 1 A monofilament made of nylon 6 resin and having a diameter of 0.91 mmφ was used as a core thread, and 18 monofilaments made of nylon 46 resin and having a diameter of 0.17 mmφ were formed on the surface of the core thread.
While applying a 0% phenol aqueous solution adhesive, it is densely wound around the core yarn and processed at a number of 85 T / M to form a side yarn layer, followed by heat treatment to integrate the core yarn and the side yarn. A resin solution prepared by dissolving nylon 46 resin in a xylene-phenol solution was coated on the surface of the side yarn layer and heat-treated to obtain a string of the present invention having a diameter of 1.30 mmφ.

Example 2 A string of the present invention having a diameter of 1.30 mmφ was obtained in the same manner as in Example 1 except that a monofilament made of nylon 6 resin and having a diameter of 0.17 mmφ was used as the side yarn.

Comparative Example 1 A diameter of 1.3 was obtained in the same manner as in Example 2 except that nylon 6 resin was used as the base resin of the coating resin layer on the side yarn surface.
A 0 mmφ string of the comparative example was obtained.

Comparative Example 2 A comparative string having a diameter of 1.30 mmφ was obtained in the same manner as Comparative Example 1 except that a monofilament made of nylon 46 resin and having a diameter of 0.91 mmφ was used as the core yarn. Table 1 shows the results of the durability test by the ordinary hitter together with the constituent resins of each layer of the obtained Examples 1-2 and Comparative Examples 1-2.

[0017]

[Table 1]

As is clear from Table 1, Examples 1 and 2 in which nylon 46 resin was used for the surface resin coating layer were compared with Comparative Examples 1 and 2 in which nylon 6 resin was used for the surface resin coating layer, The number of hits until string cutting was overwhelmingly large, and Example 1 had an improvement in durability of about 35% over the comparative example, and Example 2 had an improvement of about 20% over the comparative example.
The results were almost the same as Comparative Example 2 using Nylon 6 for the core yarn and Comparative Example 1 using Nylon 46. There was almost no difference between the shot feeling and the resilience in each Example and Comparative Example.

[0019]

According to the present invention, by using nylon 46 resin having excellent wear resistance for the side threads and the coating resin layer, a string having excellent durability without impairing the feel at impact and the resilience of the string. Can be provided.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a string showing an example of the present invention.

[Explanation of symbols]

 1 core yarn 2 side yarn 3 coating resin

Claims (2)

[Claims] 1. A string having a side thread layer in which a plurality of side threads are wound around a core thread, and having a resin coating layer on the surface of the side thread layer, wherein the resin coating layer is made of nylon 46 resin. A string that is characterized. 2. The string according to claim 1, wherein the side threads are made of nylon 46 resin.