JPS6226118Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a racket string used for tennis, badminton, etc.

In order to catch a batted ball with the gut and apply force such as cutting or driving, the surface of the gut needs to have an appropriate amount of unevenness. However, since the surface of synthetic fiber guttets is too smooth, a thin thread is wound around a thick core wire to create a winding wire, and the twist-like unevenness that appears on the surface of the winding wire captures the ball. It is designed to add force such as cut and drive to the body.

Such conventional gutts are shown in Figures 1 and 2.
As shown in the figure, a fixing agent 3 such as adhesive or resin is applied or dipped onto the winding 2 wound around the core wire 1 to fix the winding 2 to the core wire 1. There is. For this reason, winding 2 and winding 2
The twists 4 formed between are crushed by the adhesive 3,
The drawback was that the original burning effect of Gatsuto was lost. Furthermore, when the winding is multi-layered, the above-mentioned fixing must be carried out for each layer, making the process complicated and difficult. Furthermore, if polyamide fibers are used for the core wire or winding wire, if a phenolic resin is used as the fixing resin for the core wire and winding wire, the surface of the yarn will be attacked by the phenol, resulting in a significant decrease in strength. At the same time, the working environment deteriorates due to the phenol odor. Furthermore, this phenol odor has the drawback of giving an unpleasant feeling to players, and there are also problems in that there are restrictions on the selection of fixing resins.

The present invention has been made in consideration of the above circumstances, and aims to provide a racket string which is easy to cut and drive and has sufficient strength and durability to withstand the strong impact when hitting the ball.

This idea uses a thermoplastic resin A as a sheath component, and a thermoplastic resin B having a higher melting point than the thermoplastic resin A.
A racket stringer made by twisting together a plurality of synthetic fibers including at least one sheath-core composite fiber having a core component of the fibers, and fusing and fixing the fibers to each other by the sheath component of the sheath-core composite fiber. The gist is:

Hereinafter, this will be explained in detail based on drawings showing examples thereof.

Figure 3 is a schematic cross-sectional view of the sheath-core composite fiber used in the gutt of this invention, Figure 4 is a partial perspective view showing a part of the gutt of this invention in cross section, and Figure 5 is the invention. FIG. 6 is a sectional view of a racket string according to another embodiment of this invention. The sheath-core composite fiber used as a material has a thermoplastic resin A as a sheath component and a thermoplastic resin B having a higher melting point than the thermoplastic resin A as a core component, as shown in FIG. The difference in melting point between resin A for sheath component and resin B for core component occurs when resin B for core component or sheath-core composite fiber and non-sheath-core composite fiber are fixed to each other by melting resin A for sheath component. , is selected to such an extent that there is no substantial change in the shape, properties, etc. of the core component resin B or other fibers. The thickness of the layer constituting the sheath component may be sufficient to adhere the core components or other fibers to each other by melting, but it may be thicker. For example, when the sheath-core composite fiber has a diameter of about 0.7 mm, the thickness of the sheath component is selected to be about 10 μm. The cross-sectional shape of the core component is not limited to a circle.

Examples of the thermoplastic resin A that is the sheath component (low melting point) of the sheath-core composite fiber include polyamide,
Copolyamides, polyesters, copolyesters, polyethers, polyvinylidene fluoride, and the like are used. As the thermoplastic resin B which is the core component (high melting point), for example, polyamide, polyester (polyethylene terephthalate, polybutylene terephthalate), etc. are used. The resins for the sheath component and the core component can be selected from the above-mentioned resins in an appropriate combination. When thermoplastic resins of the same type are used for the sheath component and the core component, the compatibility between the two improves, and a strong product that is less likely to cause peeling phenomena is obtained, which is preferable. The volume ratio of the sheath component and the core component, the copolymerization composition and copolymerization ratio of the sheath component, etc., including the combination of the sheath component and the core component, are selected as appropriate, taking into consideration the various properties required for the gut. There is no particular limitation, and it may be adopted as appropriate.

Twisted wires containing at least one sheath-core composite fiber as shown in Figure 3 are twisted together, and the melting point is higher than the melting point of the sheath component of the sheath-core composite fiber and higher than the melting point of the core component (or other fibers). By heating at a low temperature, the sheath component is melted and each stranded wire is fused and fixed. When a plurality of sheath-core type composite fibers are used, the types may be different. FIGS. 4 and 5 show the racket string according to this invention obtained in this way. In this example 3
Since the actual sheath-core type conjugate fibers were twisted together, the twisted yarns 5, 5, and 5 all originate from the core component of the sheath-core type conjugate fibers. Then, each sheath component of the three sheath-core type composite fibers is melted to form a thin sea layer (resin layer for fusing and fixing) 6, which surrounds the twisted core components 5, 5, 5. . Core component 5
A fusion fixing resin 6 is also interposed in the joint portion 7 between the two,
In this way, three strands (core component) 5, 5,
5 is firmly fixed. In the case of the embodiment shown in FIG. 6 as another example, two of the sheath-core composite fibers are
The book core components 5, 5 and two other single fibers 8, 8 are twisted together. The sheath component is melted to form the core component 5,
5 and also extends to a part of the periphery of other single fibers 8, 8 to form a thin sea layer 6. The joints between the fibers 5, 5, 8, and 8 are fixed by fusion of the sheath components. With such a structure, due to the effect of the twisting, strength and durability enough to withstand strong impact when hitting a ball are maintained. Moreover, the twisted structure appears almost as is on the surface, and valleys 9 are also formed that create deep unevenness necessary for cutting, driving, etc.

In addition, as for the material of the other single fibers 8 used for twisting, as long as it can withstand the impact when hitting the ball,
It is not particularly limited. If possible, it is preferable to use a fiber having the same core component as the core component of the sheath-core type composite fiber, since this will reduce variations in the strength and durability of the strings. In addition, when using a resin with a melting point similar to that of the sheath component for other single fibers, both the sheath component and the other single fibers will melt, and a relatively wide sea layer will surround the core component, causing melting. Since it is fixed, the strength is further improved.

The thickness of the fibers to be twisted is preferably similar to that of the sheath-core composite fiber and other single fibers as much as possible. Usually, the thickness of the sheath-core type composite fibers and other single fibers is preferably 0.1 to 0.8 mm. When a plurality of these strings are twisted together, the thickness of the string is in the range of 1.0 to 1.5 mm. The twisting is done using a conventional twisting machine. Furthermore, it is preferable to fuse and fix the sheath components while twisting them in a heated atmosphere in order to make the weld and fixation uniform.
The temperature for fusing the sheath components is, for example, nylon 6 (melting point 215°C) for the core component and nylon 6/6 for the sheath component.
When using 66/610 (melting point 150℃), approx.
The temperature is around 160℃, but in cases where polybutylene terephthalate (melting point 224℃) is used as the core component and a copolymer of polybutylene terephthalate and polybutylene inphthalate (melting point 130℃) is used as the sheath component, the temperature is approximately 150℃.
If the front and rear parts use polyethylene terephthalate (melting point 260°C) for the core component and a copolymer of polybutylene terephthalate and polybutylene isophthalate (melting point 130°C) for the sheath component, a temperature of around 155°C is appropriate. .

In the gutt of this invention, the sheath-core composite fibers and other single fibers are twisted together as necessary, and the joints between the threads are fused and fixed by the sheath component of the sheath-core composite fibers, making it easier to hit the ball. It has enough strength and durability to withstand strong impacts over time. Due to the twisting, the surface of the string has a structure similar to a twisted structure with deep unevenness, making it easier to cut, drive, etc. The gut of this invention has the advantage that the process can be streamlined because the fibers can be twisted together and continuously heat-fused to fix the threads together.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional view of the conventional product, Figure 2 is the cross-sectional view of the conventional product.
3 is a cross-sectional view of the sheath-core type composite fiber used in the gutt according to this invention; FIG. 4 is a partial perspective view showing a part of the gutt according to this invention in cross section; FIG. 5 is a sectional view of the gutt according to this invention, and FIG. 6 is a sectional view showing another embodiment of the gutt according to this invention. 5... Core component, 6... Sea layer (resin layer for fusion and fixation) 7... Joint portion, 8... Other single fibers, 9... Valley portion.

Claims (1)

[Scope of utility model registration request] A plurality of synthetic fibers including at least one sheath-core composite fiber having a thermoplastic resin A as a sheath component and a thermoplastic resin B having a higher melting point than the thermoplastic resin A as a core component are twisted together, and A racket gutt made of fibers fused and fixed together by a sheath component of sheath-core type composite fibers.