JPH07185045A - Racket gut and its manufacture - Google Patents

Abstract

PURPOSE:To provide a racket gut using a polyester monofilament which gives a comfortable ball striking feeling to a player, changes the relation between the setting tension and the striking feeling substantially parallel to each other, and is excellent in waterproof property and inexpensive, and never vertically cracked at laying or during play by setting the vertical cracking resistance degree of the gut to a specified value or more. CONSTITUTION:A polyester polymer is melt spun, cooled, drawn by heating, and thermally treated at a temperature of 350-550 deg.C under a drawing magnification of 0.90-1.05 times so that the product of the thermal treatment time (sec) and the thermal treatment temperature ( deg.C) is within the range of 1000-3000 deg.C.sec. Thus, a gut having a diameter of 0.6-1.5mm, a tensile strength of 3.5g/d or more, a knot strength of 2.5 g/d or more, a cutting elongation of 10-60%, and a vertical cracking resistance degree of 25g or more is provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a synthetic fiber gut for use in rackets for hard and soft tennis, badminton, squash and the like.

[0002]

2. Description of the Related Art Conventionally, a racket gut, which is the etymology of gut, is made from the intestines of cows and sheep, and is still used by some players because of the feel at impact. Although these have various characteristics such as hitting sound, they also have disadvantages such as poor water resistance and high cost. Therefore, synthetic fibers, especially nylon, are now predominant in the world.
This is because the problems of low water resistance and high price, which are the disadvantages of natural gut, are solved, and the durability against repeated use is greatly improved.

However, the strength / elongation curve of nylon is S
It has a V shape, which is different from the straight line of natural gut. The S-shape means that the relationship between tension and the feel at impact does not change in parallel, and some players have seen the emergence of synthetic fiber guts, although the strength / elongation curve is close to a straight line. It was strongly requested. For these requests,
Polyphenylene sulfide (PPS) fiber called super fiber and polyether ether ketone (PEE)
K) Textiles can also be used. These are also expensive and have problems with adhesion.

As a material which can meet the above demand at low cost, polyester fiber can be mentioned. However, the polyester fiber also has a problem of slackness related to stress relaxation, but the biggest drawback is a phenomenon of vertical cracking (fibrillation) related to high crystallinity. This is because when the racket gut is stretched around the racket at about 40-80 pounds, it is necessary to grasp the gut with a clamp in order to maintain these high tensions. It cannot be offered. Also, even if it can be installed without problems,
The phenomenon of vertical cracking may occur during repeated play.

From such a background, there is a demand for the appearance of a synthetic fiber racket gut which has a strength / elongation curve close to that of a natural gut, is inexpensive, and does not cause vertical cracks during play when stretched. Of. There are various proposals for such a problem. For example, Japanese Patent Laid-Open No. 61-5666.
In Japanese Patent Publication No. 9, it is proposed to mix and spin various copolymerized polyethylene terephthalates with polyethylene terephthalate.

[0006]

However, in the proposal of the conventional Japanese Patent Laid-Open No. 61-56669, although a certain improvement effect is recognized, it is required to further improve the problem of vertical cracking.

The present invention has been made in view of the above circumstances, and gives a player a pleasant feel at impact, the tension between tension and the feel at impact change in a substantially parallel relationship, and the water resistance is excellent. It is an object of the present invention to provide a racket gut that is inexpensive and prevents the gut from vertically cracking during tensioning or during play, and a method for manufacturing the same.

[0008]

In order to achieve the above object, the racket gut of the present invention is a racket gut using a polyester monofilament having a diameter of 0.6 to 1.5 mm and a tensile strength of 3.5 g / d or more,
Knot strength is 2.5g / d or more, cutting elongation is 10-60%
And the vertical crack resistance is 25 g or more.

A method for producing a racket gut according to the present invention is a method for producing a racket gut using a polyester monofilament, wherein the polymer is melt-spun, cooled, heat-stretched, and then 0.90. The product of heat treatment time (seconds) and heat treatment temperature (° C) is 1000 to 3000 ° C at a temperature of 350 to 550 ° C under a draw ratio of 1.05 times.
-Characterized by heat treatment in the range of seconds.

In the above structure, it is preferable that the cross section of the monofilament is a substantially circular cross section or a non-circular irregular cross section, and the twist is applied 50 times or more per 1 m.

In the above construction, the polyester monofilament is preferably a polymer selected from polyester or a polyester copolymer or a mixture of polyester and a polyester copolymer.

Further, in the above-mentioned constitution, the polyester is at least one selected from polyethylene terephthalate and polybutylene terephthalate, the polyester copolymer contains polyethylene terephthalate or polybutylene terephthalate as a main component, and an isophthalic acid component and 5-sodium salt. It is preferable that at least one component selected from the sulfoisophthalic acid component is copolymerized.

[0013]

According to the structure of the racket gut of the present invention described above, the racket gut using the polyester monofilament has a diameter of 0.6 to 1.5 mm and a tensile strength of 3.5 g / d or more, Knot strength is 2.5 g / d or more, cutting elongation is 10 to 60%, and vertical crack resistance is 2
A weight of 5 g or more gives the player a pleasant feel at impact, the tension between the tension and the feel at impact changes in a substantially parallel relationship, is excellent in water resistance, is inexpensive, and prevents the gut during tension or during play. The problem of vertical cracking can be improved.

According to the structure of the racket gut manufacturing method of the present invention, there is provided a racket gut manufacturing method using a polyester monofilament, wherein the polymer is melt-spun, cooled, heat-stretched, and then melt-spun. 0.90
At a temperature of 350 to 550 ° C. under a draw ratio of ˜1.05 times,
The product of heat treatment time (seconds) and heat treatment temperature (° C) is 1000-
By heat-treating in the range of 3000 ° C. · sec, the above racket gut without vertical cracking can be efficiently and rationally manufactured.

In the above-mentioned preferred structure, the monofilament has a substantially circular cross section or a non-circular irregular cross section, and the twist is applied 50 times or more per 1 m. Can be given. Here, the non-circular atypical cross section is, for example, a gear, an ellipse, an ellipse, a polygon such as a tri-octagon,
Refers to various cross-sectional shapes such as a star. Of course, a circular cross section may be used.

Further, in the above, when the polyester monofilament is a polymer selected from polyester or a polyester copolymer or a mixture of polyester and a polyester copolymer, there is a problem that the gut is longitudinally cracked especially during stretching or during play. Can be improved.

Further, in the above description, the polyester is at least one selected from polyethylene terephthalate and polybutylene terephthalate, and the polyester copolymer contains polyethylene terephthalate or polybutylene terephthalate as a main component and an isophthalic acid component, 5
According to a preferable constitution in which at least one component selected from the sodium sulfoisophthalic acid component is copolymerized, the relationship between the tension in tension and the feel at impact changes into a substantially parallel relationship, the water resistance is excellent, and the cost is low. Can be a gut that is.

[0018]

EXAMPLES The present invention will be described more specifically below with reference to examples. The polyester fiber in the present invention is at least one selected from polyethylene terephthalate and polybutylene terephthalate, and the polyester copolymer contains polyethylene terephthalate or polybutylene terephthalate as a main component, and an isophthalic acid component and a 5-sodium sulfoisophthalic acid component. Fibers that are copolymers of at least one component selected from are used. Other copolymerizable components include glycol components such as ethylene glycol, diethylene glycol, polyethylene glycol, ipropane-1,
Examples of the acid component include 3-diol, butane-1,4-diol, polytetramethylene glycol, and the like.
A copolymer of a polymer selected from adipic acid, dibenzoic acid, naphthalene 1,4-dicarboxylic acid and the like is used.

Particularly preferably used in the present invention is 100 parts by weight of polyethylene terephthalate, and the molar ratio of terephthalic acid component: isophthalic acid component is 97: 3 to 8.
It is a polyester fiber composed of a mixture of 5 to 150 parts by weight of an isophthalic acid component copolymer [polyethylene tere (iso) phthalate] of 0:20. When these polymers are used, high strength and high knot strength are easily obtained. However, it is not limited to this.

Using these polymers, melt spinning, water cooling, drawing, and relaxation heat treatment are carried out by a conventional method to produce a monofilament. These conditions are, for example, Japanese Patent Publication No. 60-
You may manufacture using the conditions of 14845 gazette. However, the stretching ratio is not limited to this.

The monofilament thus obtained has a diameter of 1.2 to 1.5 m for tennis, for example.
m, tensile strength of 3.5 g / d or more, knot strength of 2.5 g
/ D or more, and the cutting elongation is required to be 15 to 60%. For example, when the diameter is 1.25 mm, it becomes about 15,000 denier when converted to denier, the tensile strength is 60 kg or more, and the knot strength is 45 kg or more, which can be sufficiently used as a tennis gut.

If the tensile strength and knot strength are less than the above values, the durability is insufficient and it is not practical. Further, when the elongation is less than the above range, the shot feeling is deteriorated, and when it exceeds the above range, the slack is large and it cannot be put to practical use.

In the case of badminton and squash, the diameters are different from 0.6 to 0.8 mm and 1.0 to 1.3 mm, respectively, and the other conditions are the same as in the case of tennis.
The monofilament thus obtained is then heat-treated at high temperature for a short time. This heat treatment is carried out in a separate step after once producing the monofilament, but it may be carried out in the final relaxation heat treatment step of the above-mentioned monofilament producing step.

The heat treatment conditions and the effect of preventing vertical cracking will be described in detail below. It was also found that the higher the heat treatment temperature, the greater the effect of preventing vertical cracking, but at the same time, the particularly important physical properties of the racket gut deteriorate. Only when the treatment temperature is a high temperature for a short time, it is possible to prevent vertical cracking and maintain the physical properties related to strength. That is, 0.90 to 1.
When held at a temperature of 350 to 550 ° C. under a tension of 05 times so that the product of heat treatment time and temperature is 1000 to 3000 ° C./sec, physical properties such as strength are not deteriorated and the effect of preventing vertical cracking is remarkably exerted. Of. If the tension ratio is less than 0.90 or the product of the heat treatment temperature and the heat treatment time is less than 1000 ° C./second, the strength-related physical properties can be maintained, but the vertical crack preventing effect is insufficient, and It is difficult to set the crack resistance to 13 g or more. On the other hand, if the product of the heat treatment time and the temperature exceeds 3000 ° C. · sec, the effect of preventing vertical cracking is sufficient, but the physical properties related to strength are deteriorated and problems such as fusion breakage occur, which is not preferable.

The evaluation of the prevention of vertical cracking in the present invention is carried out by notching a notch with a blade at about the center of one end of the gut and tearing it.
The resistance at this time is obtained by a tensile tester and displayed in grams. Separately, by using an actual gut tensioning machine, the racket was actually stretched and the relationship with the vertical cracks generated at this time was investigated. As a result, it was confirmed that vertical cracks did not occur if the resistance was about 25 g or more. confirmed.

Specific examples will be described below. (Example 1) Polyethylene terephthalate (manufactured by Mitsubishi Kasei Co., Ltd.) 80 parts by weight of pellets having an intrinsic viscosity of 1.10 was polycondensed with a mixture of dimethyl terephthalate and dimethyl isophthalate in a molar ratio of 90:10 and ethylene glycol. Isophthalic acid copolymer having an intrinsic viscosity of 0.73 [polyethylene tere (iso) phthalate]
20 parts by weight of a mixture of the above pellets was melted at a temperature of 285 ° C., spun (substantially circular in cross section), water-cooled,
I wound up. The undrawn yarn was heated and drawn at a draw ratio of 3. The obtained monofilament has a diameter of 1.30 mm.
(Approximately 16,500 denier), Tensile strength 70 kg, Tensile strength 4.24 g / d, Knot strength 48 kg, Knot strength 2.
It had physical properties of 91 g / d and a cutting elongation of 27%.

This monofilament has a furnace length of about 30c
m electric furnace was heated to 450 ° C. and heat-treated at a rate of 6 m / min. The residence time was 3 seconds, and the product of the heat treatment temperature and the heat treatment time was 1350 ° · sec. The heat-treated monofilament has a diameter of 1.36 mm, about 18,0
00 denier, tensile strength 69 kg, tensile strength 3.83 g
/ D, knot strength 2.88 g / d, and cut elongation 33%.

The vertical cracking resistance of the gut before heat treatment is about 1
Although it was 3 g, it was 50 g after the heat treatment. Although it was actually stretched using a gut tensioning machine, vertical cracks on the gut were not observed. In addition, when a top-ranked player actually played tennis, he was able to give the player a pleasant feel at impact. Further, the tension between the tension and the feel at impact changed into a substantially parallel relationship, which was excellent in water resistance and was inexpensive.

Example 2 Using the same pellets and conditions as in Example 1, a monofilament having a gear-shaped cross section with 12 teeth was obtained. This product was treated at 400 ° C. for 6 seconds while applying a twist number of 60 times / m. The product of the heat treatment temperature and the heat treatment time was 2400 ° · sec.

The treated product had an apparent diameter of 0.69 mm, a tensile strength of 5.40 g / d, a knot strength of 3.28 g / d, a cutting elongation of 14.3% and a vertical cracking resistance of 47 g. Although it was actually stretched using a gut tensioning machine, vertical cracks on the gut were not observed. In addition, when a top-ranked player actually played tennis, he was able to give the player a pleasant feel at impact. Further, the tension between the tension and the feel at impact changed into a substantially parallel relationship, which was excellent in water resistance and was inexpensive.

[0031]

As described above, since the racket gut of the present invention has a specific physical property value, particularly a specific vertical cracking resistance, it goes without saying when the gut is stretched. Even during repeated play, the gut is not vertically cracked, and it is possible to enjoy playing with a gut in which the tension and the shot feeling are in a parallel relationship.

Further, according to the method of the present invention, under certain heat treatment conditions, it is possible to easily produce a racket gut in which vertical cracks are unlikely to occur, and almost no deterioration in the physical properties originally required as a gut is recognized. , Can be manufactured with high productivity.

Claims (5)

[Claims] 1. A racket gut using a polyester monofilament, having a diameter of 0.6 to 1.5 m.
m, tensile strength of 3.5 g / d or more, knot strength of 2.5 g
/ D or more, the cutting elongation is 10 to 60%, and the vertical cracking resistance is 25 g or more. 2. A method for producing a racket gut using a polyester monofilament, wherein the polymer is melt-spun, cooled, heat-stretched and then 0.90.
The product of heat treatment time (seconds) and heat treatment temperature (° C) is 1000 to 3 at a temperature of 350 to 550 ° C under a draw ratio of 1.05 times.
A method for producing a racket gut, characterized by heat-treating to a temperature range of 000 ° C./second. 3. The monofilament has a substantially circular cross section or a non-circular irregular cross section, and 5 per 1 m.
The method for manufacturing a racket gut according to claim 1 or a racket gut according to claim 2, wherein twisting is performed 0 or more times. 4. The racket gut according to claim 1 or the racket according to claim 2, wherein the polyester-based monofilament is a polymer selected from polyester or a polyester copolymer or a mixture of polyester and a polyester copolymer. Gut manufacturing method. 5. The polyester is at least one selected from polyethylene terephthalate and polybutylene terephthalate, and the polyester copolymer contains polyethylene terephthalate or polybutylene terephthalate as a main component, and an isophthalic acid component and a 5-sodium sulfoisophthalic acid component. The racket gut or the method for producing a racket gut according to claim 4, which is a copolymer of at least one component selected from the group consisting of: