JPH0374593B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a synthetic fiber string used for rackets for hard tennis, soft tennis, badminton, squash, and the like. [Conventional technology] Conventionally, racket guts were made using cow or sheep intestines,
Animal fibers such as whale muscle were used. For example, when using cow intestines, first cut the cow's intestines into linear bodies, twist 15 to 20 of these linear bodies and glue them with gelatin or urethane resin to obtain twisted threads. It was used as a gut. The main reason why natural gutt made of twisted yarns of animal fibers is still favored by some professional players is that it has excellent resilience. Here, the repulsion of Guttu will be explained. As shown in FIG. 3a, the tension applied to one string 11 stretched on the racket frame 10 is generally 20 to 40 kg, but for convenience of calculation, let us assume that this is 30 kg. When the ball 12 collides with the string 11 which is stretched under such tension, the string 11 is bent as shown in FIG. 3b. Here, if the speed of the ball is 150 km, the contact time between the ball and the gut is 0.004 seconds, and the impact force per racket is 64 kg, and this is received by 6 guts, then the force acting on each gut is The impact force is about 10 kg. The ball 12 that hit Guttu 11 moves to the position shown in Fig. 3c due to Gutt's repulsive force.
It rebounds as shown in the figure, and Gatsuto 11 recovers as shown in the figure. However, natural gut has a serious drawback of poor water resistance and is very expensive, so it has not achieved widespread public demand. For this reason, synthetic fiber guts such as nylon guts, which have excellent water resistance and are inexpensive, are currently the mainstream in the market. These synthetic fiber guts have inferior resilience compared to natural guts, but the conventional reality is that they have been used unavoidably at the expense of their resilience. Table 1 below shows the ΔE of various guts. Here, ΔE is the elongation shown in FIG. 3b above expressed as a percentage of the length of the gut in a state where there is no elongation.

[Problem to be solved by the invention]

In view of the above circumstances, it is an object of the present invention to provide a racket gutt made of synthetic fibers with excellent resilience. The gut with excellent repulsion properties intended by this invention refers to one that can easily return from the stretched state as shown in FIG. 3b to the restoring state as shown in FIG. 3c. Therefore, for example, it can be said that the greater the elongation when a further load is applied under a constant load tension, the better the resilience is. [Means for Solving the Problems] In order to solve the above problems, the inventor thought that it would be sufficient to use synthetic fibers with excellent resilience as the material for the gutt, and created a synthetic fiber with superior resilience. As a result of researching and examining new materials,
The material is polyphenylene sulfide (hereinafter referred to as
It is written as “PPS”. ). Gut made of PPS fibers is highly water resistant, and as shown in Table 2, it exhibits almost the same resilience as natural gut. Table 2 also shows the resilience of polyetheretherketone, which is recently known as a functional polymer along with PPS. As shown in Table 2, polyether ether ketone gutt is inferior to PPS gutt in resilience.

[Effect]

By having the structure as described above, the present invention exhibits excellent resilience and is also able to enhance the soft feel. [Example] Below, the synthetic fiber racket gutt according to the present invention will be described in detail with reference to drawings showing one example thereof. The synthetic fiber racket gutt according to the present invention is made of five or more (preferably seven or more) PPS monofilaments obtained by spinning PPS resin, as shown in example A in FIG. Together, they constitute a core portion 1. That is, the core 1
In this example, a large diameter PPS monofilament 1a is at the center, and a plurality of slightly smaller diameter PPS monofilaments 1b are wound around it, as illustrated in FIG. 14 leather threads 2 made of nylon monofilament are wound around this core 1. When manufacturing the core 1 and arranging the leather thread 2, a nylon adhesive or the like is used as an adhesive, which allows the PPS monofilaments and the leather threads to be bonded and fixed together, and the leather thread and the core are bonded together. is fixed with adhesive. The leather threads 2 are coated with a resin coating layer 3 from above. The leather thread 2 is used to improve wear resistance, etc., but is not essential. As the leather thread 2, in addition to nylon fibers such as nylon monofilament,
Polyester fibers, aramid fibers, etc. are used,
It is possible to improve the convergence of each PPS monofilament constituting the core 1, prevent loosening, maintain desired resilience, and improve dyeability. Note that PPS resin does not have good adhesive properties, so it lacks processability. Therefore, use a nylon adhesive with good adhesive properties to secure the PPS mono (multi) filament and leather thread sufficiently. Nylon adhesives, for example, are made by dissolving nylon resin in a solvent such as phenol or formic acid, and diluting it with a solvent such as trichlorethylene, perchloroethylene, or dichloroethane as necessary, and it has extremely adhesive properties. Get rich. The resin coating layer 3 is also not essential. This resin coating layer 3 may directly cover the core portion 1. The resin coating layer 3 is formed by melting and adhering a resin, for example, to form a film. This layer 3 can prevent fiber fatigue during tensioning and ball hitting, improve durability, abrasion resistance, etc., and improve quality. As the resin, nylon, urethane, etc. are preferable from the viewpoint of water resistance and abrasion resistance. When using a PPS monofilament and a PPS multifilament together, for example, the PPS multifilament may be used as a core, and the PPS monofilament may be arranged as a skin thread around the core. When using PPS multifilament alone or when using PPS monofilament and PPS multifilament together, it is best to fix the filaments together with a nylon adhesive or the like. In this invention, PPS used as a material
Resin is a resin that has been attracting attention recently, and has a structure in which benzene nuclei and sulfur are bonded alternately in a linear chain, and the PPS fiber obtained by spinning this resin has excellent mechanical strength. It also exhibits high rigidity. Examples of the present invention will be described in more detail below. As shown in Figure 2, the diameter is 0.361mm and the strength is 7.04mm.
Kg, centered on PPS monofilament 1a with an elongation of 24.2%, and around it, a diameter of 0.241 mm, a strength of 2.84 Kg,
7 pieces of PPS monofilament 1b with elongation of 31.3%,
The core portion 1 was prepared by winding it with an S twist. At that time, the PPS monofilaments were fixed to each other using a nylon adhesive. Next, as shown in FIG. 1, 14 nylon 6 monofilaments each having a diameter of 0.235 mm were used as leather threads 2 and wound around the core 1 with a Z twist. At that time, a nylon adhesive was used to fix the PPS monofilament and the leather threads, and to fix the leather threads to each other. Furthermore, leather thread 2...
A resin coating layer 3 was formed on the outer periphery of the sample by jetting nylon 6 resin from a nozzle with a diameter of 1.37 mm. This racket has a diameter of 1.375mm and is powerful.
It was 53.1Kg, elongation was 27.1%, and knot strength was 32.0Kg.
ΔE was 5.2%. In addition, the ball had a soft feel at impact. The elastic recovery rate was determined as a percentage of the recovery of elongation when a load of 30 kg was applied in advance and a load of 10 kg was applied 20 times intermittently. As a result, the elastic recovery rate of natural gutt (1.39mmφ) was
While the elastic recovery rate of natural gutt (1.16 mmφ) was 98.1%, the elastic recovery rate of PPS gutt according to this example is 96.8%, which is slightly inferior, but is almost close to natural guttud. It was a value. When stress relaxation, which is a measure of slack, was determined as the stress retention rate when a load of 30 kg was continuously applied for 1 hour, it was 82.7% for natural gut (1.39 mmφ), whereas for this example In the case of PPS Gatsuto, it was 78.7%. When the PPS gut according to this example was actually stretched on a racket and trial hits were made with both soft and hard tennis balls, it was found that it had excellent rebound and controllability not found in conventional synthetic fiber guts. I understand. In addition, the hitting sound was pleasant, and there was little slack due to use. [Effects of the Invention] The synthetic fiber racket gutt according to claims 1 to 3 is constructed as described above, and therefore has excellent water resistance, excellent resilience, and a soft feel at impact. . Because it has excellent repulsion,
Makes a pleasant hitting sound. In terms of price, it is also cheaper than natural gutt.

[Brief explanation of drawings]

FIG. 1 is a schematic cross-sectional view showing an embodiment of the synthetic fiber racket gutt according to the present invention, FIG. 2 is a partial perspective view of the core, and FIGS. 3 a to c illustrate the repulsion properties of the gutt. FIG. A...Synthetic fiber racket gutt, 1...Core, 2...Leather thread, 3...Resin coating layer.

Claims (1)

[Scope of Claims] 1. A synthetic fiber racket stringer having at least a core portion of five or more polyphenylene sulfide monofilaments. 2. A synthetic fiber racket stringer whose core portion is at least composed of a polyphenylene sulfide monofilament and a polyphenylene sulfide multifilament. 3. A racket made of synthetic fiber, at least the core of which is made of polyphenylene sulfide multifilament.