JP2004202000A - String - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a string whose wearing is suppressed for a long period and by which good ball-hitting feel appears. <P>SOLUTION: The string uses one nylon monofilament of 1.05 mm diameter as a core string 2. As an outer layer string 4, 16 nylon monofilaments of 0.1 mm diameter are wound spirally around the core string 2 and fixed simultaneously by using a nylon-based adhesive to obtain a string core component of 1.25 mm diameter. By using thermal melting polyurethane which has 200 nm average fiber diameter, 10 nm average fiber length and 50 aspect ratio (average fiber length/average fiber diameter) and which contains 2 wt. % carbon nanofiber whose heat conductivity shows characteristic of 1,500 W/(m K) at 15°C as a micro carbon fiber 6, coating treatment is performed to the core component at ordinary temperature for obtaining the string. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

【００４２】
又、上記の試験に付け加え、これらのストリングをラケットフレームに２５０Ｎのテンションで張設して実打試験を行った。この実打試験では、一般のアマチュアプレーヤーを対象にして、実際に、実施例１、２と、比較例１〜４のストリングを張設したラケットフレームでボールを打撃し、その際、プレーヤーが体感した打撃時の打球感（プレーヤーの手に伝播する振動の抑制効果）を評価した。この時の結果を以下の表２に示す。
【００４３】
【表２】

【００４４】
このような試験結果より、本実施例１、２のストリングでは、比較例１〜４のストリングに比し、耐磨耗効果が大幅に優れると共に、ボール打撃時の振動減衰性が高く、良好な打球感が得られるものであることが確認できた。
【００４５】
【発明の効果】
以上のように、本発明では、合成樹脂製モノフィラメント及び／又は、合成樹脂製マルチフィラメントから構成されるストリングにおいて、表面コーティング樹脂層及び／又は、接着剤層に、炭素六角網面の結晶が円筒形に巻かれる単層構造或いは、多層構造を成し、その中心部に微細な中空部を有する結晶素材であって、熱伝導率が５〜３０℃の温度状態下で１０００〜３０００Ｗ／（ｍ・Ｋ）の範囲内にあり、且つその繊維径が１０〜３００ｎｍの範囲内に設定される微細炭素繊維が混入されていることにより、ストリング表面の摺動性を大幅に高める（摩擦抵抗を大幅に低減させる）ことができる。又、前記微細炭素繊維は熱伝導率が極めて高く、ストリングの交差部分で生じる摩擦熱を該交差部分以外の周辺部へ素早く分散させ放熱させることができるため、前記摩擦熱による表面コーティング樹脂層の摩耗を予防できる。更に、ストリング自体の熱伝導率が高められるため、ボール打撃時に生じるストリングの振動が熱エネルギーとして消費されるようになり、この結果、ストリングの振動減衰性が高まり、良好な打球感を得ることが可能となる。
【図面の簡単な説明】
【図１】本実施例のストリングの構成説明図。
【図２】図１のＡ−Ａ線端面説明図。
【図３】その他の実施形態に表すストリングの構成説明図。
【図４】その他の実施形態に表すストリングの構成説明図。
【図５】その他の実施形態に表すストリングの構成説明図。
【図６】その他の実施形態に表すストリングの構成説明図。
【図７】ストリングの摩耗試験方法を表す説明図。
【符号の説明】
１ ストリング
２ 芯糸
３ 接着剤層
４ 外層糸
５ 表面コーティング樹脂層
６ 微細炭素繊維
７ 錘
８ プーリー
９ モーター
１０ 連結片
１１ ストリング
１２ ストリング
１３ ストリング
２１ 芯糸
４１ 外層糸[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a string (also called gut) used for rackets such as tennis, badminton, and squash.
[0002]
[Prior art]
Heretofore, strings of natural fibers such as whale muscle and sheep intestine have been used as such strings. The strings made of such natural fibers have excellent resilience characteristics and also excellent feeling characteristics when hitting a ball. However, there is a problem that the mass productivity is poor and the durability is inferior because it is easily affected by moisture.
[0003]
In recent years, strings made of inexpensive synthetic resin excellent in water resistance, durability and mass productivity have been generally used instead of strings made of such natural fibers. As a string made of such a synthetic resin, a monofilament monofilament or a monofilament type formed by winding a thin monofilament called an outer layer yarn around a monofilament serving as a core yarn so as to surround the monofilament and bonding with a surface coating resin. Many types of strings are generally known, such as a string called a multifilament type, which is a bundle of multifilaments composed of an aggregate of single yarns having an extremely small diameter, and bonded by a surface coating resin. I have.
[0004]
Polyamide resins, polyester resins, and the like are used as the filaments constituting such strings. Among them, polyamide resins, which are particularly excellent in tensile strength, resilience, durability, and the like, are widely used. As the surface coating resin, a polyamide resin excellent in durability and a polyurethane resin excellent in weather resistance are often used.
[0005]
By the way, a string is stretched with a relatively large tension on a hitting portion of a racket. When a ball is repeatedly hit, a string stretched vertically (a vertical string) and a string stretched horizontally are stretched. There is a problem that the intersection with the (horizontal string) is worn and broken.
Therefore, conventionally, various measures for improving durability have been taken to prevent such abrasion of the strings.
[0006]
For example, the smoothness of the string surface is enhanced by applying a smooth oil such as silicone oil or wax to the surface of the string, the frictional resistance generated between the vertical string and the horizontal string is reduced, and wear is prevented. Such improved strings are generally known.
[0007]
Further, in a gut in which a plurality of synthetic fiber monofilaments are wound around a core yarn made of a single fiber of a synthetic fiber monofilament and integrally fixed by an adhesive, an appropriate amount of carbon powder is contained in the adhesive. Patent Literature 1 proposes a gut that is improved to improve wear resistance.
[0008]
Further, various proposals have been made to include whiskers in a synthetic resin layer forming the surface layer of the string in order to improve the wear resistance of the string.
[0009]
For example, a synthetic resin layer covering the outer periphery of a gut mainly composed of a synthetic resin monofilament contains potassium titanate whiskers having a fiber diameter of 0.2 to 0.5 μm and an average fiber length of 10 to 20 μm. A proposal is disclosed in Patent Document 2.
[0010]
Further, in a string for a multifilament type racket made of a polyamide-based synthetic fiber, Patent Document 3 proposes that a surface resin coating layer contains aluminum borate whiskers, and further, in a string for a monofilament type racket made of a nylon monofilament, A proposal for incorporating aluminum borate whiskers into a surface resin coating layer is disclosed in Patent Document 4 and is known.
[0011]
[Patent Document 1]
Japanese Utility Model Publication No. 59-4680 [Patent Document 2]
Japanese Patent Publication No. 2-56110 [Patent Document 3]
Japanese Patent No. 2921560 [Patent Document 4]
Japanese Patent No. 3025431
[Problems to be solved by the invention]
However, such conventionally known strings have the following disadvantages.
[0013]
That is, in the case of applying a smooth oil such as silicone oil or wax to the surface of the string, there is a problem that the smooth resin is easily removed from the surface of the string. Wear could not be prevented.
[0014]
Further, as disclosed in Patent Document 1, in a gut configured to include a carbon powder in an adhesive for fixing a plurality of synthetic fiber monofilaments, the carbon powder reinforces the adhesive. Although acting as a filler, it can suppress gut wear to some extent, but since the fiber diameter of the carbon fiber itself constituting the carbon powder is usually as large as about 5 μm to 10 μm, the carbon powder is exposed on the surface of the gut. Then, there was a problem that the smoothness of the gut surface was lost and the slidability was deteriorated (frictional resistance was increased), and the abrasion of the gut could not be sufficiently suppressed.
[0015]
On the other hand, as disclosed in Patent Document 2, in a case where a potassium titanate whisker is contained in a synthetic resin layer covering an outer periphery of a gut main body, unlike the case where the carbon powder is used, the potassium titanate is not used. Since the fiber diameter of the whisker is extremely small and the average fiber length is short, the slidability of the gut surface can be enhanced (friction resistance can be reduced). However, the potassium titanate whisker has a low thermal conductivity (5.0 to 6.0 W / (m · K) at a temperature of 5 to 30 ° C. (the temperature at which gut is used during the operation)), Since the heat dissipation is poor, the frictional heat generated at the intersection of the guts is not dissipated and tends to be intensively accumulated in the intersection region. As a result, there is a problem that the synthetic resin layer containing the potassium titanate whisker is melted and relatively easily worn due to the accumulation of the frictional heat, and it is not possible to suppress gut wear for a long period of time. .
[0016]
Further, since the thermal conductivity of the gut itself is reduced by containing the potassium titanate whisker, the vibration of the gut generated at the time of hitting the ball is hardly consumed as heat energy, and as a result, the vibration damping property of the gut is reduced. There is also a disadvantage that the golf ball is inferior and it is difficult to obtain a good shot feeling.
[0017]
Further, as disclosed in Patent Literature 3 and Patent Literature 4, in a multifilament type racket string made of a polyamide-based synthetic fiber or a monofilament type racket string made of a nylon monofilament, a surface resin coating layer has a hoof. Even in a string configured to contain aluminum oxide whiskers, similar to Patent Document 2, although the slidability of the string surface can be greatly improved (friction resistance is reduced), the boric acid is used. Since the thermal conductivity of the aluminum whisker itself is low (4.0 to 6.0 W / (m · K) under the condition of 5 to 30 ° C. (the temperature at which the string is used in the practice)), the intersection of the strings occurs. It is difficult to dissipate the frictional heat generated in the portion, and the aluminum borate whisker is included. Is expected that the surface resin coating layer will be easily worn by the accumulation of the frictional heat, it is difficult to suppress the abrasion of the gut over a long period.
[0018]
Further, since the thermal conductivity of the string itself is reduced by containing the aluminum borate whisker, there is a problem that the shot feeling is deteriorated.
[0019]
Accordingly, an object of the present invention is to provide a string capable of suppressing wear of the string for a long period of time and exhibiting a good feel at impact in view of such conventional problems.
[0020]
[Means for Solving the Problems]
In order to achieve the above object, the present invention has the following configuration.
That is, the string according to claim 1 of the present invention is a string in which a surface coating resin layer is arranged around a synthetic resin monofilament or a synthetic resin multifilament serving as a core yarn, wherein the surface coating resin layer is A crystal material having a single-layer structure or a multilayer structure in which a crystal of a carbon hexagonal mesh is rolled into a cylindrical shape, having a fine hollow portion at the center thereof, and having a thermal conductivity of 5 to 30 ° C. It is characterized in that fine carbon fibers having a fiber diameter within a range of 1000 to 3000 W / (m · K) under a condition and a fiber diameter of 10 to 300 nm are mixed.
[0021]
A second aspect of the present invention is the string according to the first aspect, wherein a synthetic resin monofilament or a synthetic resin multifilament serving as a core thread is surrounded by a plurality of synthetic resin monofilaments serving as an outer layer thread or a synthetic resin monofilament. In a string in which a resin multifilament is fixedly arranged via an adhesive layer and a surface coating resin layer is arranged around the string, the fine carbon fiber is applied to the surface coating resin layer and / or the adhesive layer. It is characterized by being mixed.
[0022]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is an explanatory diagram of a configuration of a string of the present embodiment, and FIG. 2 is an explanatory diagram of an end face taken along line AA of FIG.
[0023]
That is, the string 1 of the present embodiment comprises a core yarn 2 made of a synthetic resin monofilament, and a plurality of synthetic resin monofilaments helically wound around the core yarn 2 via an adhesive layer 3. A monofilament type string composed of an outer layer yarn 4 composed of: and a surface coating resin layer 5 covering the periphery of the outer layer yarn 4, wherein the surface coating resin layer 5 forming the surface layer of the string 1 has fine carbon It has a configuration in which the fibers 6 are mixed.
[0024]
The fine carbon fiber 6 is formed by, for example, a vapor deposition method, an arc discharge method, a laser abrasion method, a plasma synthesis method, or the like, and has a single-layer structure or a multilayer structure in which a crystal of a carbon hexagonal mesh is wound in a cylindrical shape. It is a crystalline material having a structure and a fine hollow portion at the center thereof, and is made of a very fine carbon fiber material having a fiber diameter on the order of nanometers. As such fine carbon fibers 6, carbon nanofibers or carbon nanotubes are used.
This kind of fine carbon fiber 6 has excellent slidability, and when mixed into the surface coating resin layer 5 forming the surface layer of the string 1, greatly improves the slidability of the surface of the string 1 (friction resistance). Can be greatly reduced). Further, the fine carbon fiber 6 has an extremely high thermal conductivity as compared with other known materials, so that the frictional heat generated at the intersection of the strings 1 can be quickly dispersed to the periphery other than the intersection to radiate heat. Thereby, abrasion of the surface coating resin layer 5 due to the frictional heat can be prevented. Further, since the thermal conductivity of the string itself is increased, the vibration of the string 1 generated at the time of hitting the ball is consumed as heat energy. As a result, the vibration damping property of the string 1 is increased, and a good shot feeling is obtained. It is possible to obtain.
[0025]
The finer the carbon fiber 6, the smaller the fiber diameter, the more excellent the slidability and the higher the thermal conductivity. In the present embodiment, the fiber diameter is set in the range of 10 to 300 nm, particularly in the range of 20 to 200 nm, and the average fiber length is in the range of 2 to 30 μm, particularly 5 to 20 μm as suitable for the string 1. Is used. Further, the thermal conductivity is in the range of 1000 to 3000 W / (m · K) under the condition of 5 to 30 ° C. (the temperature at which the string 1 is used in the implementation), particularly 1500 to 2000 W / (m · K). Those within the range of K) are used.
[0026]
In the above description, the upper limit of the fiber diameter of the fine carbon fibers 6 is set to 300 nm. If the fiber diameter is larger than this, good slidability cannot be provided on the string surface, and the heat resistance may be reduced. This is because the conductivity is low and the heat radiation is inferior. Also, the lower limit is set to 10 nm, because if the fiber diameter is smaller than this, handling becomes difficult, and the fiber cannot be evenly contained in the surface coating resin layer 5 without unevenness. This is because variation may occur.
[0027]
Further, the upper limit of the average fiber length is set to 30 μm because if the average fiber length is longer than this, the string surface cannot have good slidability and the surface coating resin layer 5 The reason for this is that it is difficult to make the average fiber length evenly contained, and the lower limit is set to 2 μm because if the average fiber length is smaller than this, handling becomes difficult.
[0028]
The reason why the upper limit of the thermal conductivity is set to 3000 W / (m · K) is that, in the currently known fine carbon fiber 6, the upper limit that can be obtained in the setting range of the fiber diameter is this value. The reason why the lower limit is set to 1000 W / (m · K) is that when the thermal conductivity is lower than this, frictional heat is difficult to disperse, and the wear of the string 1 is reduced over a long period of time. This is because it is not possible to suppress the vibration, and the vibration damping property of the string 1 is inferior, so that a good shot feeling cannot be exhibited.
[0029]
The amount of the fine carbon fiber 6 used in the surface coating resin layer 5 is in the range of 0.5% by weight or more and 10% by weight or less, particularly in the range of 1% by weight or more and 5% by weight or less. Preferably, it is mixed.
According to various experimental results, when the use amount of the fine carbon fibers 6 is less than 0.5% by weight, the wear resistance and the vibration damping property of the string 1 cannot be sufficiently increased, and 10% by weight. If the amount is more than the above, there is a problem that it is difficult to mix the string 1 evenly into the surface coating resin layer 5. No good evaluation was obtained.
[0030]
The core yarn 2 and the outer yarn 4 constituting the string 1 of this embodiment are made of a polyamide synthetic resin such as nylon 6, nylon 66, nylon 6-10, nylon 6-12, and the like. The adhesive layer 3 for fixing the outer yarn 4 to the core yarn 2 is made of a polyamide synthetic resin.
Further, as the surface coating resin layer 5, a polyamide-based synthetic resin excellent in adhesion to the outer layer yarn 4, a urethane-based synthetic resin excellent in abrasion resistance and weather resistance, and the like are preferably used.
[0031]
As described above, in the present embodiment, as the structure of the string 1, the core yarn 2 made of a synthetic resin monofilament, the outer yarn 4 made of a plurality of synthetic resin monofilaments, and the periphery of the outer yarn 4 are formed. Although the present invention has been described by taking as an example the structure composed of the covering surface coating resin layer 5 and the present invention, the present invention is not limited to this. For example, as shown in FIG. A string 11 having a structure in which a surface coating resin layer 5 is coated around a core yarn 2 made of a monofilament, or as shown in FIG. A string 12 having a structure in which an outer layer yarn 41 composed of a filament is arranged and a surface coating resin layer 5 is coated around the outer yarn 41 or a synthetic resin as shown in FIG. The surface coating resin layer 5 on the core yarn 21 around consisting multifilaments may be a string 13 of the coated structure.
[0032]
Further, in the present embodiment, an example is shown in which the fine carbon fibers 6 are mixed only into the surface coating resin layer 5 constituting the surface layer of the string 1, but as shown in FIG. It can also be mixed in the layer 3. In this case, the thermal conductivity of the string itself is further increased, and the vibration damping property is greatly improved.
[0033]
【Example】
In order to confirm the effects of the present invention, strings of Examples 1 and 2 and Comparative Examples 1 to 4 below were prepared.
[0034]
(Example 1)
One nylon monofilament having a diameter of 1.05 mm is used as the core yarn 2, and 16 nylon monofilaments having a diameter of 0.1 mm are helically wound around the core yarn 2 as the outer layer yarn 4, and simultaneously a nylon-based adhesive is used. It was fixed using an agent to obtain a string core component having a diameter of 1.25 mm.
In this core component, as fine carbon fibers 6, a temperature state in which the average fiber diameter is 200 nm, the average fiber length is 10 nm, the aspect ratio (average fiber length / average fiber diameter) is 50, and the thermal conductivity is 15 ° C. Using a hot-melt polyurethane containing 2% by weight of carbon nanofiber (trade name: VGCF-H type, manufactured by Showa Denko KK) exhibiting a characteristic of 1500 W / (m · K) below, coating treatment is performed at room temperature. A string was obtained.
[0035]
(Example 2)
In the string forming process of Example 1 above, a string containing 3% by weight of the fine carbon fibers 6 in an adhesive for winding and fixing the outer layer yarn 4 around the core yarn 2 was obtained.
[0036]
(Comparative Example 1)
A string having a structure in which the fine carbon fibers 6 were omitted was prepared as Comparative Example 1 while the basic string structure was the same as in Examples 1 and 2 described above.
[0037]
(Comparative Example 2)
Instead of the fine carbon fiber 6 of Example 1, a temperature state where the average fiber diameter was 7 μm, the average fiber length was 1400 μm, the aspect ratio (average fiber length / average fiber diameter) was 200, and the thermal conductivity was 15 ° C. A string coated with a hot-melt polyurethane containing 2% by weight of carbon powder (trade name: Torayca, manufactured by Toray Industries, Inc.) having a property of 8.0 W / (m · K) below was used as a comparative example 2 Prepared as.
[0038]
(Comparative Example 3)
Instead of the fine carbon fibers 6 of Example 1, the average fiber diameter was 1 μm, the average fiber length was 50 μm, the aspect ratio (average fiber length / average fiber diameter) was 50, and the thermal conductivity was 15 ° C. A string coated with a hot-melt polyurethane containing 2% by weight of potassium titanate whiskers (trade name: Teismo D, manufactured by Otsuka Chemical Co., Ltd.) having a property of 5.3 W / (m · K) below Was prepared as Comparative Example 3.
[0039]
(Comparative Example 4)
Instead of the fine carbon fiber 6 of Example 1, the average fiber diameter was 0.8 μm, the average fiber length was 20 μm, the aspect ratio (average fiber length / average fiber diameter) was 25, and the thermal conductivity was 15 ° C. Coating using a hot-melt polyurethane containing 2% by weight of aluminum borate whiskers (trade name: Arbolex, manufactured by Shikoku Kasei Kogyo Co., Ltd.) exhibiting a property of 5.6 W / (m · K) under temperature conditions The processed string was prepared as Comparative Example 4.
[0040]
The strings of Examples 1 and 2 and Comparative Examples 1 to 4 were subjected to the following wear tests.
That is, as shown in FIG. 7, a string A, which is the same sample, is wrapped around a string A, which is a sample, a weight 7 having a weight of 10 kg is fixed to one end of the string B, and the string B is hung down. Is rotatably connected to the tip of a connecting piece 10 fixed to the rotating shaft of a motor 9 via a pulley 8, and the motor 9 rotates to make a reciprocating motion of 10 cm per second at a rate of one reciprocation per second. The number of times until A and B were cut by abrasion was measured. The measurement results at this time are shown in Table 1 below.
[0041]
[Table 1]

[0042]
In addition to the above test, these strings were stretched on a racket frame with a tension of 250 N to perform an actual hitting test. In the actual hitting test, the ball was hit with a racket frame in which strings of Examples 1 and 2 and Comparative Examples 1 to 4 were stretched, targeting a general amateur player. The shot feeling at the time of hitting (the effect of suppressing the vibration transmitted to the player's hand) was evaluated. The results at this time are shown in Table 2 below.
[0043]
[Table 2]

[0044]
From these test results, the strings of Examples 1 and 2 have significantly better abrasion resistance and higher vibration damping properties at the time of hitting a ball than the strings of Comparative Examples 1 to 4, and have good performance. It was confirmed that the shot feeling was obtained.
[0045]
【The invention's effect】
As described above, according to the present invention, in a string composed of a synthetic resin monofilament and / or a synthetic resin multifilament, a crystal having a hexagonal carbon face of a cylinder is formed on a surface coating resin layer and / or an adhesive layer. A crystalline material having a single-layer structure or a multilayer structure wound into a shape and having a fine hollow portion in the center thereof, and having a thermal conductivity of from 1,000 to 3,000 W / (m) at a temperature of 5 to 30 ° C.・ The fine carbon fiber whose fiber diameter is in the range of K) and whose fiber diameter is set in the range of 10 to 300 nm is mixed, so that the slidability of the string surface is greatly improved (friction resistance is greatly increased). Can be reduced). In addition, the fine carbon fibers have extremely high thermal conductivity, and the frictional heat generated at the intersections of the strings can be quickly dispersed and radiated to peripheral portions other than the intersections, so that the surface coating resin layer due to the frictional heat can be used. Wear can be prevented. Furthermore, since the thermal conductivity of the string itself is increased, the vibration of the string generated at the time of hitting the ball is consumed as heat energy. As a result, the vibration damping property of the string is increased, and a good shot feeling can be obtained. It becomes possible.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating the configuration of a string according to an embodiment.
FIG. 2 is an explanatory diagram of an end face taken along line AA of FIG. 1;
FIG. 3 is a diagram illustrating a configuration of a string according to another embodiment.
FIG. 4 is a diagram illustrating a configuration of a string according to another embodiment.
FIG. 5 is a diagram illustrating a configuration of a string according to another embodiment.
FIG. 6 is a diagram illustrating a configuration of a string according to another embodiment.
FIG. 7 is an explanatory view showing a string wear test method.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 String 2 Core thread 3 Adhesive layer 4 Outer thread 5 Surface coating resin layer 6 Fine carbon fiber 7 Weight 8 Pulley 9 Motor 10 Connecting piece 11 String 12 String 13 String 21 Core thread 41 Outer thread

Claims (2)

In a string in which a surface coating resin layer is arranged around a synthetic resin monofilament or a synthetic resin multifilament serving as a core yarn, a crystal of a carbon hexagonal mesh plane is wound around the surface coating resin layer in a cylindrical shape. A crystalline material having a single-layer structure or a multilayer structure and having a fine hollow portion in the center thereof, and having a thermal conductivity of 1000 to 3000 W / (m · K) at a temperature of 5 to 30 ° C. A string containing fine carbon fibers having a diameter within a range and a fiber diameter set within a range of 10 to 300 nm. Around a synthetic resin monofilament or a synthetic resin multifilament serving as a core yarn, a plurality of synthetic resin monofilaments or a synthetic resin multifilament serving as an outer layer is fixedly arranged via an adhesive layer, and the periphery thereof. 2. The string according to claim 1, wherein the fine carbon fibers are mixed in the surface coating resin layer and / or the adhesive layer. 3.

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