JPH0316409B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a method for producing a single covering elastic yarn, which is formed by winding a thermoplastic synthetic fiber yarn such as polyamide around an elastic yarn such as polyurethane.
In particular, the present invention relates to a method for producing fine-grained single covering elastic yarn (SCY) useful as material for socks, stockings, and other socks. [Prior art] Elastic yarns are made by wrapping (covering) thermoplastic synthetic fibers (covering yarns) such as long fibers of polyamide or polyester around elastic yarns (core yarns) such as polyurethane yarns. It is widely used to cover the disadvantages of dyeing properties, mechanical strength, abrasion resistance, etc.
126335, etc.). These coated elastic yarns are generally
A flat yarn (drawn yarn that has not been subjected to any processing) is used as the covering yarn, and a crimped yarn obtained by false twisting is used as a type of covering elastic yarn. It has also been proposed (Special Publication No. 18063/1983). However, in coated elastic yarns used in fashion-oriented applications that require a high degree of transparency and uniformity, such as stockings, crimped yarns that significantly impair these properties cannot be used; The yarn used was exclusively flat yarn. For covered elastic yarns covered with flat yarns, the covering properties can be improved by increasing the number of windings (number of covering twists) of the covering yarn, but the number of windings of the covering yarn is As the torque of the coated elastic yarn increases, problems such as snarls occurring during knitting and irregularities in the resulting knitted fabric become more noticeable. It wasn't a good thing. [Problems to be Solved by the Invention] Therefore, in order to solve the problem of increased torque accompanying improved coverage, the present invention reduces torque without reducing the number of governing twists and increases the The main objective is to provide a method for producing an excellent coated elastic yarn that has sufficient governing twist to exhibit coverage and a uniform appearance, yet exhibits sufficiently low torque characteristics. That is, the main object of the present invention is to provide a fabric with excellent coverage and uniformity, easy knitting without snarling and frizz during knitting, and high transparency and a well-balanced knitted surface. The object of the present invention is to provide a method for obtaining an excellent single-covering elastic yarn that provides a knitted fabric with excellent elasticity and durability. Another object of the present invention is to obtain a single covered elastic yarn that can be made into a knitted fabric with excellent transparency and a flat and uniform appearance. [Means for solving the problem] In order to achieve this object, the present invention creates a single covering elastic yarn by winding a covering yarn made of long fibers of a thermoplastic polymer around a core yarn made of elastic fibers. The method for producing a single covering elastic yarn is characterized in that a non-bulky torque type false twisted yarn having a torque in the same direction as the winding direction is used as the covering yarn. Here, the torque in the same direction as the winding direction means that the torque of the false twisted yarn is reduced by winding and twisting. The elastic fibers used in the method of the present invention are preferably polyurethane elastic fibers commonly referred to as spandex fibers, but other types of elastic fibers may also be used. On the other hand, polyamide, polyester, polyolefin, polyacrylic fibers, etc. are used as the long fibers of thermoplastic polymers that make up the covering yarn.
Polyamide fibers with excellent dyeing properties, mechanical strength, abrasion resistance, etc. are preferred, and among polyamides, nylon 6 and nylon 66 fibers are particularly preferred as they have particularly excellent properties. The non-bulky torque type false twisted yarn used as the covering yarn refers to a false twisted yarn that does not substantially exhibit bulkiness in the covered state, and is generally referred to as torque type false twisted yarn. It is. For this torque type false twisted yarn, the normal woolly false twisting processing method has a false twist number (Tt/m)
25000~√ for its yarn fineness (D denier)
False twisting is carried out in the range of D~30000/√, while the range is 5000/√≦T≦20000~√, preferably in the range of 8000/√≦T≦18000/√, and furthermore, the heat setting is The temperature is 40 to 130 degrees Celsius lower than the melting point of the yarn,
Preferably, it can be obtained by false twisting at a lower temperature of 50 to 90°C. The torque-type false-twisted yarn obtained under these false-twisting conditions has almost no deformation of the single yarn cross section due to the false-twisting process (see Figure 1), so it prevents irritation caused by the covered elastic yarn and has excellent symmetry. preferred for retaining The winding direction of the covering yarn is a direction that reduces the torque of the false twisted yarn, which means that when using false twisted yarn with S direction torque obtained by S-twist false twisting, the winding direction (covering twist direction) is defined as the S direction, and on the other hand, when using a false twisted yarn with a Z direction torque obtained by Z twisting and false twisting, it means that the winding direction (covering twist direction) is the Z direction. In addition, single covering yarn production in which a covering yarn is wound around a core yarn is carried out by a normal single covering yarn manufacturing method, that is, single covering yarn in which a single covering yarn is wrapped around a core yarn in a single layer. Just do it. [Function] The present invention uses a non-bulky torque type false twisted yarn as a covering yarn in order to reduce torque without reducing coverage or uniformity.
Further, the winding direction of the covering yarn is the same as the torque of the false twisted yarn. In the case of a single covering elastic yarn (hereinafter simply referred to as covered elastic yarn), the torque due to the winding (covering twist) of the covering yarn appears as the torque of the covering elastic yarn, and this torque significantly reduces the number of covering twists. However, conversely, if the number of covering twists is reduced, the covering property is reduced and the appearance is impaired. Therefore, we investigated ways to reduce the torque of the covered elastic yarn without lowering the number of covering twists, and found that a torque-type false twisted yarn, which has torque in the same twist direction as the covering twist direction, was used as the covering yarn to create a covered elastic yarn. If refined, it is possible to reduce the torque caused by covering twist without impairing the covering properties or uniformity, and since it is non-bulky, it will not impair the transparency or uniformity of the resulting covered elastic yarn. The present invention was based on the knowledge that this is not the case. That is, in the present invention, a torque type false twisted yarn having a torque in the same direction as the covering twist direction is used as a covering yarn that generates a large torque, so that the torque of the torque type false twisted yarn is due to the covering twist. This allows the torque of the entire covered elastic yarn to be reduced without reducing the number of covering twists. As a result, even if a sufficient number of covering twists is applied to give the resulting covered elastic yarn good coverage and uniformity, the torque can still be reduced. On the other hand, crimped type false twisted yarn (Woolly type false twisted yarn) obtained by false twisting at a high false twist number (Tt/m) of about 25000/√ to 30000/√ shows bulkiness in the covered state. Therefore, when crimped type false twisted yarn is used as the covering yarn, the surface appearance of the obtained covered elastic yarn becomes uneven, making it impossible to obtain a knitted fabric with good transparency and a flat, uniform appearance, which is the objective of the method of the present invention. . Furthermore, since the crimped type false twisted yarn has a deformed single yarn cross section as shown in Figure 3, the resulting coated elastic yarn becomes irritated, which also hinders the uniformity of the knitted fabric. Become. [Examples and Comparative Examples] - Example 1 A 20-denier, 3-filament spandex fiber yarn was stretched 3.2 times and single covering was carried out in the winding direction S using a normal covering machine. The covering thread used at this time was 22 denier 7
The filament was a nylon 66 filament yarn, and the yarn form was a flat yarn, a torque type false twisted yarn, or a crimp type false twisted yarn, as shown in Table 1. The false twisted yarn used here was a false twisted yarn having a torque in the S direction obtained by performing S direction false twisting, heat setting, and untwisting at the number of false twists and the temperature shown in Table 1. The torque of the obtained covered elastic yarn is
Torque is developed by applying a load of 1 g to the center of 1 m of covered elastic yarn and letting it hang down.The number of twists produced (number of twists per 50 cm) is measured, and the value converted to the number of twists per 1 m (torque index) ), and its quality was evaluated using the same criteria as in the case of coverage below. Further, the coverage of the obtained covered elastic yarn was evaluated visually using a magnifying glass according to the following criteria. ◎: Excellent △: Slightly poor ○: Good ×: Poor Next, the false twisted yarn with torque in the S direction was
An S-covered elastic yarn formed by covering in the Z-direction, a Z-covered elastic yarn formed by covering a false-twisted yarn having a torque in the Z-direction in the Z-direction, and a 15-denier 3-filament nylon 66 flat yarn are combined into an S-covered elastic yarn. Yarn, flat yarn, Z-coated elastic yarn, and flat yarn were inter-knitted in the order of usual to form a knitted fabric, and its evenness was evaluated using the same criteria as in the case of coverage.

【table】

[Table] As can be seen from the results, the coated elastic yarns of Examples Nos. 1 to 8 obtained by the method of the present invention have reduced torque without reducing the number of covering twists, and have excellent covering properties and low torque properties. It was possible to obtain a coated elastic yarn with a high degree of uniformity, and it was possible to obtain a knitted fabric with excellent uniformity without any snarling caused by snarling during knitting. On the other hand, in the case of the conventional method using flat yarn as the covering yarn (Comparative Examples No. 11 and 12), when the number of covering twists is high, coverage and uniformity are good, but torque is high. There was a problem.
Further, as can be seen from the results of Comparative Example No. 13, when a crimped type false twisted yarn was used as the covering yarn, although the torque was improved, the evenness of the knitted fabric was significantly deteriorated. - Example 2 Single covering was carried out in the same manner as in Example 1 except that a nylon 6-filament yarn of 15 denier and 5 filaments was used as the covering yarn, and the results are shown in Table 2.

〔Effect of the invention〕

The single covering elastic yarn obtained by the method of the present invention uses a non-bulky torque type false twisted yarn as the covering yarn, and the direction in which the covering yarn is wound is set in such a direction that the torque of the false twisted yarn is reduced. Therefore, the torque of the covered elastic yarn can be reduced without reducing the number of covering twists. Therefore, it is possible to obtain an excellent single-covered elastic yarn that has high coverage, a uniform appearance, and exhibits low torque characteristics. This single covering elastic yarn is easy to knit, has good covering properties, and is useful for obtaining high-quality knitted fabrics with excellent transparency and a flat, uniform appearance.

[Brief explanation of drawings]

Figure 1 shows the torque-type false twisted yarn used as the covering yarn in the method of the present invention (torque-type false twist yarn in Example No. 3).
FIG. 2 is a cross-sectional view showing a single yarn cross-sectional form of a flat yarn used as a conventional covering yarn (flat yarn in Comparative Examples Nos. 11 and 12). It is a diagram. Moreover, FIG. 3 is a sectional view showing a single yarn cross-sectional form of the crimp type false twisted yarn used as the covering yarn in Comparative Example No. 13.

Claims (1)

[Claims] 1. In a method for producing a single covering elastic yarn by winding a covering yarn made of long fibers of a thermoplastic polymer around a core yarn made of elastic fibers, the covering yarn is made of a core yarn made of a core yarn made of elastic fibers, and a covering yarn made of long fibers of a thermoplastic polymer. 1. A method for producing a single covering elastic yarn, characterized in that a non-bulky torque type false twisted yarn having torque is used.