JP2011206177A - Gut for racket - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gut for a racket whose characteristics are hard to change by the environment, which creates a soft feeling when it hits a ball, has an excellent ball controlling property and a high durability at the same time and also exhibits a high stretching property over the racket.SOLUTION: A polyester gut is braided by using at least partly polyester monofilaments which are 0.05-1.0 mm in diameter. The elongation of the gut for the racket under a tension of 220 N is within 2.0-5.0% and its elongation under a tension of 500 N is within 8.0-20%.

Description

  The present invention relates to a racket gut for use in tennis, badminton, squash, etc. More specifically, it does not easily change characteristics due to the environment, and has a soft shot feeling, excellent ball controllability, and excellent durability. Further, the present invention relates to a racket gut that is excellent in stretchability to a racket.

  Conventionally, a natural gut made of animal fibers represented by sheep intestine and whale muscle has been used as a gut for a sports racket.

  However, natural gut is excellent in resilience, ball control, impact resistance, etc., but since it is inferior in water resistance, it has a short service life and is expensive, so in recent years it has become durable, mass-productive and economical. An excellent synthetic resin gut is used.

  As these synthetic resin guts, polyamide guts are used relatively frequently due to their soft shot feeling and excellent ball control. However, polyamide guts are sufficient for environmental changes such as temperature and humidity. There was a problem that it was difficult to give the player stable ball control because they could not cope and the elongation, strength, elastic modulus, etc. changed.

  Under such circumstances, polyester guts that are less likely to cause characteristic changes due to environmental changes, have a strong elongation curve that is very close to natural gut, and are excellent in ball control are being put to practical use.

  However, due to its rigidity, polyester guts do not always have sufficient resilience, impact resistance and ball control, and are not easily stretched on rackets, making them easier to fibrillate and durable. Since there is also a disadvantage of being inferior, there is an increasing demand for improvement on these.

  As a method for improving the fibrillation of the polyester gut, a method of performing heat treatment under special conditions (for example, see Patent Document 1) has been proposed, but this method improves the fibrillation to some extent, Since the tension to the racket, resilience, impact resistance, etc. have not been improved, it was insufficient as a racket gut.

  On the other hand, as a method for improving the shock absorption of the racket gut, a mono-multi type racket gut in which three or more hexagonal cross-section monofilaments are bonded (for example, see Patent Document 2), a polyester resin And a method of making a sea-island composite of a polyamide resin, a fluorine resin, and a polyolefin resin (see, for example, Patent Document 3), etc. Although improved, there is a problem that when used as a racket gut, the adhesive surface peels off or the interface between the sea and island components of the sea-island composite peels off, resulting in low durability. Was left.

  Moreover, as a method for improving the stretchability, resilience, and impact resistance of the racket gut, a method using a monofilament that uses a specific polyester raw material and clears specified parameters (for example, see Patent Document 4). Although proposed, this method uses the monofilament as a racket gut as it is, so the gut surface is smooth and it is difficult to spin the ball, resulting in poor ball controllability. There was room for improvement.

JP-A-7-185045 JP 2006-345963 A JP 2007-330772 A Japanese Patent Laid-Open No. 2003-239134

  The present invention has been achieved as a result of studying the solution of the problems in the prior art as an object.

  Accordingly, an object of the present invention is to provide a racket gut that is difficult to cause characteristic changes due to the environment, has a soft shot feeling, excellent ball controllability, excellent durability, and has excellent stretchability to the racket. There is.

  In order to achieve the above object, according to the present invention, a polyester gut formed by using a polyester monofilament having a diameter of 0.05 to 1.0 mm for at least a part and having an elongation at a tension of 220 N is 2. There is provided a racket gut characterized by having an elongation of 0 to 5.0% and a tensile strength of 500 N in a range of 8.0 to 20%.

In the racket gut of the present invention,
The polyester monofilament is used for at least a part, and is formed by a blade.
The polyester monofilament is 50% or more of the entire racket gut,
The component other than the polyester monofilament is a pseudo monofilament in which at least one monofilament or multifilament selected from a polyamide resin, a polyolefin resin, a fluorine resin, and a polyphenylene sulfide resin is formed, and It is preferable that the polyester gut is bonded with at least one adhesive selected from a thermoplastic resin adhesive, a photocurable resin adhesive, and a thermosetting resin adhesive. As a condition.

  According to the present invention, as described below, it is difficult to cause characteristic changes due to the environment, and has a soft feel at impact, excellent ball controllability, excellent durability, and excellent rackability to the racket. You can get a gut.

  The racket gut of the present invention will be described below.

  The racket gut of the present invention is formed by using at least a portion of a polyester monofilament having a diameter of 0.05 to 1.0 mm, preferably 0.1 to 0.9 mm, and the racket gut has a tension of 220 N. When the elongation is 2.0 to 5.0% and the tension is 500N, the elongation is 8.0 to 20%, preferably the elongation when the tension is 220N is 2.5 to 4.5% and the tension is 500N. It is important that the elongation is in the range of 10-15%.

  Here, if the polyester monofilament diameter is thinner than 0.05 mm, the single yarn diameter is too thin and extremely weak against the friction between the guts, and as with the racket gut using multifilaments, it is durable. It is not preferable because it will be inferior to. On the other hand, if the monofilament diameter is larger than 1.0 mm, the gut diameter is too large, and the gut will not pass through the grommet.

  In addition, when the elongation of the racket gut of the present invention when the tension is 220N and 500N is smaller than the above range, not only the rebound is deteriorated when the ball is hit, but a fast serve cannot be launched. This is not preferable because the vibration when hitting the ball cannot be absorbed and a burden is placed on the elbow. On the other hand, when the elongation at a tension of 220 N and 500 N exceeds the above range, the ball controllability is deteriorated, which is not preferable.

  Another feature of the racket gut of the present invention is that at least a portion of the polyester monofilament is used for stringing. When the polyester monofilament is used as it is as a racket gut, the surface of the gut is smooth. For this reason, the frictional force with the ball is lowered, and the spin property when the ball is spun or the spin of the spun ball is stopped to make it non-rotated is not preferable.

  Here, the polyester monofilament stringing method is not particularly limited, and examples include a method of aligning monofilaments and covering them with side yarns, a method of twisting polyester monofilaments, and a method of braiding polyester monofilaments like braids. However, a bladed method is preferably employed because the shape of the completed racket gut is stable.

  Examples of the polyester used as a material in the present invention include polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polypropylene terephthalate, polymethylene naphthalate, polybutylene naphthalate, polypropylene naphthalate, or a copolymer or blend of two or more thereof. Polyester and the like can be mentioned, among which polyethylene terephthalate is preferably used.

  In the racket gut of the present invention, the polyester monofilament is 50% or more, preferably 60% or more of the whole racket gut. When the polyester monofilament is less than 50% of the entire racket gut, there is a tendency that it is difficult to maintain the difficulty of property change due to the environment, which is characteristic of the polyester gut.

  Here, as a component other than the polyester monofilament constituting the racket gut of the present invention, a monofilament made of a polyamide resin, a polyolefin resin, a fluorine resin, a polyphenylene sulfide resin, or a pseudo monofilament made by stringing a multifilament, etc. It is preferable that the player who wants flexibility is made of polyamide monofilament and the hard hitter that is durable is made of polyphenylene sulfide.

  Furthermore, the racket gut of the present invention is an adhesive selected from thermoplastic resin-based adhesives, photo-curable resin-based adhesives, and thermosetting resin-based adhesives when stringing a monofilament or after stringing. By performing adhesive coating using an agent, further excellent durability can be exhibited.

  The monofilament used for the racket gut of the present invention includes, for example, a pigment, a dye, a weathering agent, a light resistance agent, an ultraviolet absorber, an antioxidant, a heat resistance agent, a fluorescent whitening agent, and a crystallization inhibitor, if necessary. Various additives such as a plasticizer and a terminal group blocking agent can be added within the range of not impairing the object of the present invention, after the raw material polymerization step, after the polymerization, or just before spinning.

  Furthermore, the cross-sectional shape of the monofilament constituting the racket gut of the present invention is substantially circular, polygonal such as triangle, quadrilateral, pentagon, clover shape, petal shape, star-shaped irregular cross section, track shape, rectangular shape, etc. For example, a flat shape obtained by connecting atypical cross sections can be appropriately selected within a range that does not impair the object of the present invention.

  The thus obtained racket gut of the present invention combines the difficulty of changing the characteristics of polyester gut due to the environment, the soft feel of nylon gut, excellent ball controllability, and excellent durability. Since the structure is also improved, application as a racket gut for tennis, badminton, squash, etc. is highly expected.

  Hereinafter, the racket gut of the present invention will be described in more detail based on examples. Note that the racket gut in the examples was evaluated by the following method.

[Intermediate elongation]
According to the definition of JIS L1013. That is, after the sample taken in the shape of a bowl is left in a temperature / humidity adjustment chamber at 20 ° C. and 65% RH for 24 hours, a “Tensilon” RTM500 type tensile tester manufactured by Orientec Co., Ltd. is used. Yarn length: 250 mm Tensile speed: 300 mm The strength elongation curve until breakage was measured under the conditions of / min, and the elongation (%) at 220 N and the elongation (%) at 500 N were read from the strength elongation curve.

[diameter]
The diameter of the monofilament was randomly measured at 5 points with a digital micrometer (manufactured by MITUTOMO) and displayed as the average value.
Moreover, about the diameter of the gut, the major axis and the minor axis were each measured at five points and displayed as an average.

[Durability evaluation of racket gut]
The racket gut of the present invention was actually stretched on a tennis racket with a tension of 50 pounds.
The tennis ball hits the face of the tennis racket at a speed of 100 km / h, a launching interval of 15 times / minute, a launching distance of 50 cm, and a launching angle of 40 °. Sex was evaluated. (Unit: times)

[Racket evaluation of racket gut]
A high-level tennis player actually tried out a tennis ball, causing rebound, ball control, impact resistance, and environmental changes compared to using natural gut and conventional synthetic resin gut. The difficulty was evaluated in the following two stages.
○: It was equivalent to or close to natural gut.
X: It was equal to or less than the conventional synthetic resin gut.

[Evaluation of stretchability of racket gut]
The ease of tension when the racket gut was actually stretched on the racket with a tension of 50 pounds was evaluated in the following two stages as compared with the case where the natural gut was stretched.
○: Equivalent to natural gut or easier to stretch than natural gut,
X: It was cut off during the tensioning or could not be tensioned. Or it was harder to lay than natural gut.

[Example 1]
Mitsui Chemicals polyethylene terephthalate resin (J055: Intrinsic viscosity 1.37) is supplied to an extruder type spinning machine, melted and kneaded at a spinning temperature of 290 ° C., then passed through a filtration layer in a spinning pack through a gear pump. A polyester undrawn yarn spun from a spinning nozzle for cross-sectional yarn and immediately cooled and solidified in a warm water bath at 75 ° C. was obtained. Subsequently, the obtained unstretched yarn was first stretched 3.0 times in a hot water bath at 90 ° C., and then secondary stretched 1.8 times in a dry heat atmosphere at 180 ° C. to give a total draw ratio of 5.4. The polyester monofilament having a diameter of 0.205 mm was manufactured by doubling and further relaxing treatment by 0.95 times in a dry heat atmosphere at 240 ° C.

  The produced monofilament was stringed by a 16-punch stringing machine to create a blade gut having an outer diameter of 1.26 mm. Table 1 shows the evaluation results when the prepared gut is used as a racket gut.

[Example 2]
Four polyester monofilaments prepared in Example 1 were made by SZ twisting to produce four twisted pseudo monofilaments, and four pseudo monofilaments were further made by SZ twisting to produce a twisted yarn gut having an outer diameter of 1.25 mm. . Table 1 shows the evaluation results when the prepared gut is used as a racket gut.

[Example 3]
Toray polyphenylene sulfide resin (E2080: MFR = 90) is supplied to an extruder type spinning machine, melted and kneaded at a spinning machine temperature of 330 ° C., then passed through a filtration layer in a spinning pack through a gear pump, and a circular cross section. Immediately after spinning from the yarn spinning nozzle, polyphenylene sulfide undrawn yarn was obtained by cooling and solidifying in warm water at 80 ° C.

  Subsequently, the obtained undrawn yarn was subjected to primary drawing 3.0 times in a warm water bath at 95 ° C., followed by secondary drawing 1.25 times in a dry heat atmosphere at 130 ° C. to obtain a total draw ratio of 3. The polyphenylene sulfide monofilament having a diameter of 0.205 mm was manufactured by heat setting under constant tension under a dry heat atmosphere of 150 ° C.

  Twelve polyester monofilaments prepared in Example 1 and four polyphenylene sulfide monofilaments were evenly arranged and made by a 16-placing machine to make a blade gut having an outer diameter of 1.27 mm. Table 1 shows the evaluation results when the prepared gut is used as a racket gut.

[Example 4]
Copolymer polyamide resin (M6021H4: relative viscosity 4.65) manufactured by Toray was supplied to extruder type spinning, melted and kneaded at a spinning temperature of 270 ° C., passed through a filtration layer in a spinning pack through a gear pump, and circular. A polyamide undrawn yarn was obtained by spinning from a spinning nozzle for cross-sectional yarn and immediately solidifying by cooling in a warm water bath at 10 ° C.

  Subsequently, the obtained undrawn yarn was subjected to primary drawing at 3.8 times in a steam drawing bath at 100 ° C., and then subjected to secondary drawing at 1.74 times in a dry heat atmosphere at 180 ° C. to give a total draw ratio of 6. A polyamide monofilament having a diameter of 0.205 mm was manufactured by carrying out a relaxation heat treatment of 0.9 times in a dry heat atmosphere at 170 ° C.

  Twelve polyester monofilaments produced in Example 1 and four polyamide monofilaments were arranged evenly and made by a 16-placing machine to make a blade gut having an outer diameter of 1.20 mm. Table 1 shows the evaluation results when the prepared gut is used as a racket gut.

[Comparative Example 1]
Mitsui Chemicals polyethylene terephthalate resin (J055: Intrinsic viscosity 1.37) is supplied to an extruder type spinning machine, melted and kneaded at a spinning temperature of 290 ° C., then passed through a filtration layer in a spinning pack through a gear pump. A PET undrawn yarn spun from a spinning nozzle for cross-sectional yarn and immediately cooled and solidified in a warm water bath at 75 ° C. was obtained. Subsequently, the obtained unstretched yarn was first stretched 3.0 times in a hot water bath at 90 ° C., and then secondary stretched 1.8 times in a dry heat atmosphere at 180 ° C. to give a total draw ratio of 5.4 times. Furthermore, a PET monofilament having a diameter of 1.25 mm was manufactured by performing a relaxation treatment of 0.95 times in a dry heat atmosphere at 240 ° C.

  Table 1 shows the evaluation results when the monofilament is used as a gut as it is.

[Comparative Example 2]
The polyamide monofilament having a diameter of 0.205 mm manufactured in Example 4 was stringed by a 16-punch stringing machine to create a blade gut having an outer diameter of 1.25 mm. Table 1 shows the evaluation results when the created gut is used as a racket gut.

[Comparative Example 3]
Four Toray polyethylene terephthalate multifilaments (1100T-72-702C) were made from SZ with four pseudo monofilaments, and the four pseudo monofilaments were further made from SZ to create an outer shape of 1.31 mm. A multifilament gut was prepared.

Table 1 shows the evaluation results when the prepared gut is used as a racket gut.

  As is clear from the results in Table 1, the racket guts (Examples 1 to 4) satisfying the conditions of the present invention are less susceptible to property changes due to the environment of the polyester gut and the softness of the polyamide gut. It can be seen that this is a highly practical racket gut that has both a shot feeling, excellent ball controllability, and excellent durability, and further improved tensioning to the racket.

  On the other hand, the racket guts (Comparative Examples 1 to 3) that do not satisfy the conditions of the present invention are only those that cannot sufficiently exhibit the effect as a racket gut.

  For example, a racket gut (Comparative Example 1) in which the diameter of the polyester monofilament is 1.25 mm and the stringing process is omitted is low in elongation at 500 N and the rebound of the gut is deteriorated. Not only was the shock absorption worsen, but the spinability to control the rotation of the ball also worsened, and it was not practical. In addition, the racket gut (Comparative Example 2), in which the gut material is changed to polyamide monofilament, increased in both elongation at 220N and elongation at 500N, and the tension was not stable when stretched on the racket. In addition, the ball hitting performance and durability deteriorated, and further, the characteristics changed due to the environment, which lacked practicality. Furthermore, the racket gut using the polyester multifilament instead of the polyester monofilament (Comparative Example 3) had good stretchability and hitting performance. As a result, it was poor in durability and lacked practicality.

  As described above, the racket gut of the present invention has both the difficulty of changing characteristics due to the environment of the polyester gut, the soft shot feeling of nylon gut, excellent ball controllability, and excellent durability. Since the racket has been improved, it is highly expected to be used as a racket gut for tennis, badminton, squash and the like.

Claims (4)

A polyester gut made of polyester monofilaments having a diameter of 0.05 to 1.0 mm, at least partially. The elongation is 2.0 to 5.0% at a tension of 220 N and the elongation at a tension of 500 N. A racket gut having a degree in the range of 8.0 to 20%. 2. The racket gut according to claim 1, wherein the polyester monofilament is used for at least a part and is formed by a braid. The racket gut according to claim 1 or 2, wherein the polyester monofilament is 50% or more of the entire racket gut. The component other than the polyester monofilament is a pseudo monofilament in which at least one monofilament or multifilament selected from a polyamide resin, a polyolefin resin, a fluorine resin, and a polyphenylene sulfide resin is formed. The racket gut according to any one of claims 1 to 3.