JPH0560954B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for producing synthetic resin guts used mainly for various rackets for hard tennis, as well as soft tennis, badminton, squash, and racquetball.

[Conventional technology]

There are three main characteristics required of guts used in various rackets: high durability, appropriate resilience, and flexibility.

High durability requires high tensile strength as well as high abrasion resistance.

When I recently obtained some of the world's representative guts for tennis, I found that the average weight of 14 kinds of natural guts made from cow intestines was 64.7 kg. Similarly, the average value for 11 types of nylon was 66.5Kg, while for polyester it was 66.5Kg.
It weighed 69.2Kg.

In order to be recognized by players as having extremely high durability, it is thought that the tensile strength must have a value of approximately 100 kg or more.

Repulsion, another required characteristic, has improved significantly since the racket was changed from the traditional wooden racket to a carbon racket, which increased the racket's elasticity and face area. Beginners still desire even greater repulsion, but for top-class players, excessive repulsion means a loss of control.

For this reason, top-class players
It was hoped that Gatsuto would emerge with repulsive properties that could be controlled by his own will.

The resilience is mainly controlled by the tensile elongation of the gut. With conventional natural guts, it is approximately 20-25%,
For synthetic fiber gutts, it is around 27-33%. A tensile elongation of 10% or less is considered to be a range that can be controlled by one's will. If it is less than 2%, no repulsion can be expected at all, and the firmness function is completely lost. For example, when a carbon fiber product such as that shown in Japanese Patent Publication No. 13990/1983 is used as a stringer for a tennis racket, it can only be expected to have a carbon fiber content of less than 2%, and cannot be applied to stringers for the above-mentioned reasons.

The third necessary property, flexibility, is also important, and even if the durability and resilience are satisfactory, if it is not flexible, it will not be able to serve the purpose. For example, Utsukai 59-
Guttu made of a core-sheath type composite fiber with a sheath made of low melting point nylon as shown in Japanese Patent Publication No. 5958, and
It goes without saying that high durability and low elongation cannot be obtained with the gutt made by fusing the core yarn and skin yarn immediately after spinning, as shown in Publication No. 55-26903, and the former has a low melting point nylon content. There were too many, and since the latter was essentially one monofilament, it did not have sufficient flexibility.

[Problem that the invention seeks to solve]

This invention solves the above-mentioned problems, and is aimed mainly at top-class players, including professional players, who play a large number of competitions. It provides a manufacturing method.

Another purpose is that in general, when professional players play a match, they have natural guts as well as natural guts.
To provide a method for producing a gut that is durable enough to at least require one racket for each match, since even synthetic fiber guts cannot be completed in time unless at least several rackets with strung guts are prepared.

Furthermore, the other objective is to improve controllability because if the ball flies too far beyond the player's will, controllability will be lost, and controlling the ball according to the player's will is the key to gaining an advantage in the game. The present invention provides a method for producing gatsuto.

Furthermore, other objectives are that the characteristics required for Guttu, in addition to those related to hitting the ball, cannot be fully demonstrated unless the handling such as tensioning is good.
The present invention provides a method for producing guttu that is flexible and easy to handle.

[Means and actions for solving the problem]

In order to achieve the above object, the method for manufacturing gutt according to the present invention involves mixing a plurality of aramid fiber multifilaments and several low melting point nylon filaments, heating the converged mixture and melting the nylon filaments. A core material is made by fusing a plurality of aramid fibers together, and a plurality of aramid fiber filaments and several nylon filaments are wound or braided around the outer circumferential surface of the core material, and then this outer circumferential surface is covered with nylon. It is coated with resin.

The aramid fiber used in this invention is a multifilament of para-aromatic polyamide.
The tensile strength is about 18 to 22 g/d, and the tensile elongation is about 2 to 5%. Compared to nylon fibers traditionally used for guts, it has two to three times the strength and one-tenth the elongation.

It has a tensile modulus of about 10 times and is rigid, and unless it is a multifilament, it cannot be flexible and cannot be used for guts.

A plurality of the above multifilaments are aligned to have several thousand deniers, and then twisted or braided. This is because the desired tensile elongation of the string cannot be obtained only by the elongation of the raw yarn, and elongation is given by structural factors. A number of twists of several hundred twists/m or less is sufficient.

Repulsion and controllability are compatible when the elongation of the gatsuto is between 2 and 10%, but the desirable elongation of the gatsuto is 5.
~8% can be achieved with these means.

In addition, it is necessary to mix low melting point nylon filament for the above alignment.
The low melting point nylon is melted by subsequent heat treatment,
It is used to bond aramid fibers together. If it is not glued, it will easily break when it becomes stiff.
Quality and performance cannot be fully demonstrated.

Low melting point nylon is made by copolymerizing various nylons, such as nylon 6, 66, 610, 11, and 12. The melting point can be changed depending on the type and copolymerization ratio.

A melting point of 110 to 120°C is preferable from the viewpoints of flexibility, permeability, and handleability.

It is important to mix low melting point nylon when aligning multiple aramid fibers in a filament. Therefore, unlike when using a solution adhesive, it can fully penetrate into the multifilament of aramid fibers.

For this reason, even when the string is made into a string, it does not bend easily, does not lose its flexibility, and has reasonable flexibility.

Next, the string-like body thus obtained is used as a core material, and a plurality of aramid fiber filaments and several nylon filaments are wound or braided around the outer periphery thereof.

The aramid fiber filament used here is thinner than that used for the core material. 100～
A material of about 300 denier is used as it is or heated.

At the same time, ordinary nylon monofilament of about 100 to 700 deniers is also used.

The aramid fiber filament here not only contributes to improving the tensile strength of the entire gut, but also greatly contributes to improving the abrasion resistance, which is essential for high durability.

Further, the nylon monofilament is used to enhance the effect of the nylon adhesive used in winding with an anchor effect.

After that, the entire surface is coated with nylon resin. The wound product is coated with molten nylon, but from the viewpoint of wear resistance, nylon is coated.
It is more advantageous to use 66. It is advantageous for the appearance of braided materials to be treated with a nylon solution.

After this, a smoothing agent such as silicone or paraffin wax is applied to create a firm finish.

〔Example〕

Aramid fiber 1500 denier multifilament 1 (Kevlar manufactured by Dupont) has a melting point of 110~
Mix 100 denier multifilament 2 (Elder manufactured by Toray Industries, Inc.), a low melting point nylon, at 120℃.
It was twisted in the S direction with a twist number of 220T/m. The mixing ratio of aramid fiber at this time was 6.7%.

Next, these three pieces were twisted together in the Z direction at a twist rate of 110 T/m.

Thereafter, heat treatment was performed in an atmosphere at 130° C. for 2 minutes to melt the low melting point nylon 2 and fuse the aramid fibers to form a single body A. Three pieces of this single yarn A were twisted together and twisted yarn B was used as a core material.

Twenty-four strands of 200 denier Kepler Multifilament 3 and four 450 denier nylon 6 monofilament 4 were wrapped around the outer periphery using a nylon adhesive.

Next, this outer peripheral portion was coated with molten nylon 66.

A silicone solution was applied and the product was cut into 12m lengths.

The physical properties of this gut were that the tensile strength was 150 kg, the knot strength was 51.2 kg, the tensile elongation was 5.0%, and the diameter was 1.35 mm.

This gut was stretched on the vertical string of a carbon racket with a tension of approximately 30 kg. In the horizontal direction, normal nylon gutters were stretched with a tension of approximately 27 kg.

When this racket was tested by several world-class professionals, it was proven that it has controllability and durability that cannot be obtained with conventional gutts.

〔Effect of the invention〕

This invention involves mixing and converging a plurality of aramid fiber multifilaments and several low melting point nylon filaments, heating the mixture to melt the nylon filaments, and creating a core in which a plurality of aramid fibers are fused together. A string for a racket, characterized in that a plurality of aramid fiber filaments and several nylon filaments are wound or braided around the outer peripheral surface of the core material, and the outer peripheral surface is further coated with a nylon resin. Because it is related to the manufacturing method, it has become possible to achieve high durability and controllability, which was difficult with conventional gutts.

High durability is achieved by extremely high tensile strength and high abrasion resistance due to the aramid fibers wound or braided around the outer periphery of the core material.

The high controllability is due to the tensile elongation being set at 5 to 8%.

By mixing a specific amount of low-melting point nylon and fusing the aramid fibers, we were able to achieve flexibility that is difficult to obtain with high-elasticity and high-strength guts, and also solved the problem of bending.

These effects have been proven by world-class professional athletes.

[Brief explanation of the drawing]

The drawings show an embodiment of the gut according to the present invention, and FIG. 1 is a perspective view thereof, and FIG. 2 is an enlarged sectional view thereof. 1... Aramid fiber multifilament, 2... Low melting point nylon filament, 3... Aramid fiber multifilament, 4... Nylon monofilament, D... Nylon coating layer.

Claims (1)

[Claims] 1. Mixing a plurality of aramid fiber multifilaments and several low melting point nylon filaments,
The converged material is heated to melt the nylon filaments, and a plurality of aramid fibers are fused together to form a core material, and a plurality of aramid fiber filaments and several nylon filaments are placed on the outer peripheral surface of the core material. A method for manufacturing racket guts, which comprises winding or braiding the strings, and further coating the outer peripheral surface with nylon resin. 2 The melting point of low melting point nylon filament is 110~
The method for producing guttu according to claim 1, characterized in that the temperature is 120°C. 3. The method for manufacturing gutt according to claim 1, wherein the gutt has a tensile strength of 120 to 150 kg and a tensile elongation of 5% to 8%.