JPH06218081A - String for racket - Google Patents

Abstract

PURPOSE:To provide a string having a good balance together with excellent hitting performance, long durability and high stretchability are provided by using fibers containing fluorine as fibers at least in a part constituting a sheath section in a gut of core sheath structure made of nylon. CONSTITUTION:This string is composed of a core component fibers 4 and covering component fibers 5 which are wound around the core component, and both the fibers 4 and fibers 5 are made of nylon filaments, and at least in a part of fibers constituting a sheath, fibers 3 containing fluorine are used. And the fibers 4 and 5 are fixed by means of an adhesive layer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a racket string (gut) for tennis, badminton, squash, etc.
Regarding More particularly, it relates to a racket string having a core-sheath structure and using fibers of a specific polymer.

[0002]

2. Description of the Related Art Three functions required for a racket string are hitting performance, durability and stretchability.
The hitting property includes resilience, controllability, easiness of rotation on the ball, hit feeling at hitting, hit feeling including hitting sound, and the like. In terms of durability, the stretched string has two types: loosening due to stress relaxation and cutting due to frictional wear of each hit ball. The stretchability is the ease with which the string can be stretched on the racket, and no matter how excellent the performance is, if the stretchability has a problem, the practicality is poor. For example, in the case of a string having high rigidity, loosening due to stress relaxation may occur over time even if the tension is set immediately after the string is stretched on the racket. However, the above-mentioned three functions have different degrees of importance, and the importance is positioned in the order of hitting performance, durability, and stretchability, and in some cases, 3: 2: 1 weighting is performed.

Conventionally, racket strings are generally
It has been developed and commercialized with emphasis on hitting ability, and in fact,
There are many products on the market that explain that they have good hitting properties.

Another trend is that the number of strings having a small diameter has been increasing in recent years in the world. This is also the result of emphasizing hitting performance. For example, in tennis, the diameter is 1.41 to 1.49 mm for several years.
No. 15 gauge and 1.33 to 1.41 mm 15 L gauge were mainly used, but recently, diameters of 1.26 to 1.
Most of them are 34 mm 16 gauge ones.

Furthermore, most recently, some have diameters of 1.
22-1.30 16L gauge and 1.16-1.24m
The number of meters of 17 gauge is also increasing. In addition, some users have begun to request even 18 gauges with a diameter of 1.06 to 1.16 mm. These tendencies are evidence that the user attaches great importance to hitting. In other words, the smaller the diameter of the string, the greater the flexibility when hitting a ball with the same speed, and the more repulsive the ball is, which improves the hitting performance.

In addition, the hitting sound, which is an important factor for the refreshing feeling of sports, is also improved to satisfy the hitting feeling. BACKGROUND ART Conventionally, a racket string having a core-sheath structure, which is composed of at least a core component made of filament fibers and a shoe component made of filament fibers wound around the outer peripheral surface of the core component or braided, is known. (Actual development 60
No. 168857, Japanese Utility Model Publication No. 1-42069). It is also known to use a vinylidene fluoride resin (fiber) having an irregular cross section for a racket string (Japanese Patent Laid-Open Nos. 56-166863 and 56-70).
772 publication).

[0007]

However, the above-mentioned tendency of hitting performance is adversely affected from the viewpoint of durability. That is, not only the natural gut which is said to have good hitting properties, but also the synthetic fiber string which is considered to have good hitting properties, such as those made of polyetheretherketone fiber or nylon multifilament fiber, has poor durability. The reality is that many are sufficient. In addition, a fine gauge nylon filament fiber string generally has a smaller durability as its diameter becomes smaller, particularly, the durability is greatly reduced due to abrasion.

For example, when comparing the durability of two types of strings made of nylon filament fibers having almost the same structure and having different diameters, the number of hits until the racket is stretched and cut is 1.28 mm and 1.35 mm. That is about 40% lower than that of the above. Therefore, under the current circumstances, the string for racket is becoming the main body of the world under the priority of hitting property at the expense of durability.

However, even if a person who is engaged in racket sports or a person who can afford it is satisfied with these tendencies, it is not satisfied with students, school children, and people in developing countries who cannot afford it, and endurance. There is a great demand for a good string.

On the other hand, as a durable gut, an aramid fiber string is commercially available, and some users are satisfied with it, and it is ranked as the most durable string in the world every year. However, the elongation of this string is only a few percent and the hitting property is insufficient, so that it cannot satisfy the requirements of general average players together with the thick gauge string.

Regarding the stretchability, at present, silicon,
Although it is dealt with by applying a smoothing agent such as wax, it is not always sufficiently satisfied at the sports shop where the actual work is performed.

As described above, no string has hitherto existed which simultaneously satisfies the hitting property, durability and stretchability, which are important required properties of the string for a racket. That is, if the hitting ability is emphasized, it is a normal phenomenon that the durability is lowered, and if the durability is emphasized, there is a problem that the hitting ability and the stretchability are lowered.

In order to solve the above-mentioned conventional problems, the present invention does not sacrifice any of the three functions required for the racket string, and all of them are excellent strings, that is, excellent hitting performance and durability. An object of the present invention is to provide a string for a racket having good tension and good balance.

[0014]

In order to achieve the above object, a racket string of the present invention is wound or braided around a core component made of filament fiber and an outer peripheral surface of the core component made of filament fiber. A racket string having a core-sheath structure composed of at least a footwear component, wherein the core component fiber and the footwear component fiber both contain a nylon filament fiber as a main component, and at least one of which constitutes the sheath portion. The part of the fibers is a fiber made of a polymer containing fluorine.

In the present invention, the fiber made of a polymer containing fluorine means a fiber made of a resin containing a fluorine atom in the molecule, and the resin is polytetrafluoroethylene (PTFE) or tetrafluoroethylene. Copolymer (PFA) with perfluoroalkyl vinyl ether,
Tetrafluoroethylene-hexafluoropropylene copolymer (FEP), ethylene-tetrafluoroethylene copolymer (ETFE), polychlorotrifluoroethylene (PCTFE), trifluorochloroethylene resin (PCT)
FE), tetrafluoroethylene-ethylene copolymer (ETF
E), polyvinylidene fluoride (PVDF), polyvinyl fluoride (PVF) and the like.

[0016]

According to the above-mentioned racket string of the present invention, at least a core component made of filament fiber and a wearing component made of filament fiber wound or braided on the outer peripheral surface of the core component are constituted. A core-sheath structure racket string, wherein the core component fiber and the underwear component fiber both contain a nylon filament fiber as a main component, and at least a part of the fibers constituting the sheath portion contains a fluorine-containing polymer. By using the fiber made of, it is possible to obtain a well-balanced string having excellent hitting performance, durability and stretchability.

[0017]

EXAMPLES The present invention will be described in more detail with reference to the following examples. PTFE, PFA, FEP, and ETF which are easily formed into fibers among the fibers made of the above-mentioned polymer containing fluorine
E, PCTFE and PVDF are preferred. Of these fibers, monofilaments with a diameter of 50 to 300 microns are preferred. Also, a multifilament having a denier of about 50 to 300 can be used.

It is desirable that the strength is high, but the elongation is important, and the elongation at break of about 25 to 40% is desirable. These fluorine fibers are used as a shoe component in which one to several fibers are wound or braided around the outer peripheral surface of a core component made of filament fibers together with nylon fibers.

This is because, if used in a too large amount, the fluorine fiber may not be adhered well and may be peeled off during use, which may lower the durability. From this point of view 1
It is desirable to use 0 or less.

After the fluorine fiber is wound around the outer peripheral surface of the core component, it is processed or coated with a resin solution or a molten resin. This further improves the durability. 1 to 4 schematically show examples of the cross section of the gut 1 according to one embodiment of the present invention. In FIG. 1, as a gut 1, a twisted multifilament is wound around a core component fiber and a plurality of sheath component filament fibers 2 are wound.
Further, the fiber 3 containing fluorine is used for at least a part of the filament fibers of the synthetic resin filament fiber 2 of the sheath component. Other filament fibers include nylon (for example, nylon-
6 or 6,6-nylon, etc.) is used. Reference numeral 6 denotes an internal adhesive portion. FIG. 2 shows a core component fiber 4 made of a filament fiber and a coating component fiber 5 made of a filament fiber and wound around the outer peripheral surface of the core component. Both the core component fiber 4 and the coating component fiber 5 are nylon filaments. 1 shows a gut 1 that is made of fibers and at least a part of the fibers that form the sheath is a fiber 3 containing fluorine. The core component fiber 4 and the covering component fiber 5 may be fixed by the adhesive portion 6. Although FIG. 2 illustrates a monofilament as the core component fiber, a multifilament may be used.

FIG. 3 shows a gut 1 having a structure further including a coating layer 7 around the coating component fiber 5 of FIG. Figure 4
FIG. 4 is a cutaway perspective view of FIG. 3. In the above, Gut 1
It is preferable that the outer diameter of is about 0.5 to 2.0 mm. The fiber 2 and the core component fiber 4 are 1000 to 200.
The coating component fiber 5 is 30 to 10
About 00 denier is preferable. Here, denier means the weight (gram) per fiber length of 9000 m.

In FIGS. 1 to 4, the fluorine-containing fiber 3 shows two single fibers each, but two or more single fibers may be used, and a plurality of elastic fibers are present side by side. May be.

Next, a concrete example will be described. Example 1 In this example, a string for tennis will be described.

Nylon 6 monofilament having a diameter of 1.0 mm was used as the core component fiber, and nylon 6 monofilament having a diameter of 0.115 mm was used as the component fiber to be worn.
PF which is a copolymer of one and tetrafluoroethylene with a diameter of 0.140 mm and perfluoroalkyl vinyl ether
Four A-fluorine fibers were wound in a spiral shape and simultaneously fixed with a nylon adhesive. The surface was then coated with hot melt nylon 6. A sectional view of this product is shown in FIG.

The resulting string has a tensile strength of 8
The strength was 2.2 kg, the knot strength was 45.7 kg, the elongation was 29.8 percent, and the diameter was 1.299 mm. This string was stretched on a carbon fiber reinforced resin racket having a face area of 110 square inches with a vertical and horizontal tension of 60 pounds. The stretchability was very good.

Then, an actual tennis ball was shot at a launch speed of 127 Km / hour, a launch interval of 15 times / minute,
The shot was continued at a launch distance of 50 cm until the string was cut.

Two tests, 1,150 and 1, respectively
It was 164 times. As a comparative example, nylon fiber was used in place of the PFA, all of the component fibers of the footwear were nylon fibers, and 25 fibers were used in the same manner, and the durability was examined in the same manner. The result was 538 times. A good shot feeling was obtained even when the ball was actually hit.

Example 2 In this example, an example of a string for badminton will be described.

A multifilament of nylon-6,6 of 1500 denier was twisted at a rate of 80 turns / m, and this was used as a core component fiber, and the outer peripheral portion was two nylon 6 monofilaments having a diameter of 0.060 mm and a diameter of 0. 0.049 mm
ET, which is a copolymer of ethylene tetrafluoride and ethylene
One FE was aligned, wound on a small bobbin, and braided on a total of 8 bobbins to make a component fiber for the footwear.

This string state was resin-processed with an alcohol-soluble nylon resin solution, and then the surface was coated with hot-melt nylon 6. The obtained string has a tensile strength of 26.7 Kg and a knot strength of 1
4.1Kg, Elongation 26.8%, Diameter 0.748
It was mm.

This string was tensioned on a real badminton racket with a tension of 25 pounds. The stretchability was very good. 25.5m in diameter on this string surface
m, a plastic ball of 11 g in weight, launch speed, 64.8 Km / hour, launch interval, 15 times / minute,
At the launch distance, 15 cm, the string was continued to be cut.

The number of ejections before cutting was 1,250. Change ETFE to the same as other nylon,
As a result of the same test, cutting was performed 512 times. The racket in which the string of this example was stretched had a good hitting property even when actually hitting.

[0033]

As described above, according to the racket string of the present invention, the core component made of filament fiber and the component of the wound fiber which is made of filament fiber and is wound or braided on the outer peripheral surface of the core component. A racket string having a core-sheath structure composed at least of, wherein the core component fibers and the underwear component fibers both contain a nylon filament fiber as a main component, and at least a part of the fibers constituting the sheath portion is By using a fiber made of a polymer containing fluorine, it is possible to form a well-balanced string having excellent hitting performance, durability and stretchability. Moreover, the manufacturing cost can be reduced.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a racket string according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of a racket string according to another embodiment of the present invention.

FIG. 3 is a cross-sectional view of a racket string according to still another embodiment of the present invention.

FIG. 4 is a cutaway perspective view of FIG.

[Explanation of symbols]

 1 Gut 2 Synthetic Resin Filament Fiber of Sheath Component 3 Fiber Containing Fluorine 4 Core Component Fiber 5 Covering Component Fiber 6 Adhesive Part 7 Covering Layer

Claims (1)

[Claims] 1. A racquet string having a core-sheath structure, comprising at least a core component made of filament fibers and a shoe component wound or braided on the outer peripheral surface of the filament fibers. In addition, both the core component fiber and the footwear component fiber contain nylon filament fiber as a main component, and at least a part of the fibers constituting the sheath portion are fibers made of a polymer containing fluorine. Racket string.