JPH0317935B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to nylon 66, which is made by doubly wrapping nylon 66 long fiber yarn around an elastic thread such as polyurethane.
Concerning improvements in double-covered elastic yarns. In particular, it relates to a nylon 66-coated elastic yarn useful as a material for socks, stockings, etc. [Conventional technology] Nylon 66 is used around elastic threads such as polyurethane.
Wrapping long fibers twice (double covering) is widely used to overcome the disadvantages of elastic yarns, such as dyeing properties, mechanical strength, and abrasion resistance. This double-covered covered elastic yarn is generally manufactured by wrapping a nylon covering yarn of 70 to 20 deniers twice around an elastic yarn of 20 to 70 deniers. For example, the number of twists of the bobbin thread is 2600 tons. /m, needle thread twist count 1800t/m
Wrapping is carried out to a degree of 100 degrees (Japanese Patent Application Laid-open No. 19146/1983, etc.), and it is widely used for socks, stockings, etc. The covering properties of this covered elastic yarn can be improved by increasing the yarn fineness of the covering yarn, increasing the number of single yarns, and increasing the number of windings (number of covering twists) of the covering yarn. can be improved. However, when the yarn fineness of the covering yarn is increased, there is a problem that the covering elastic yarn itself becomes thicker. Therefore, in fashion-oriented application fields such as stockings, where transparency of the resulting product is strongly required and the thickness of the covering elastic yarn itself cannot be increased, it is necessary to increase the covering yarn's thickness. Fineness
Make it as thin as 18 denier or less and reduce the number of wraps.
The amount must be increased to around 3000-4000t/m. However, when the number of windings of the covering yarn is increased in this way, there is the problem that the production speed of covering is significantly reduced, and as a result, the torque of the obtained covered elastic yarn increases, which causes problems such as during knitting. Problems arise in that snarls and stitch irregularities in the resulting knitted fabric increase. Therefore, in order to actually produce it industrially, it is necessary to reduce the torque by significantly increasing the number of twists in the inner covering and significantly decreasing the number of twists in the outer covering. It has been difficult to satisfy both productivity and quality. In addition, when using nylon 66 long fibers as coating threads, conventionally, so-called drawn threads (13-
(Has a high boiling water shrinkage rate of about 14%) was used to manufacture covered elastic yarn, so when this covered elastic yarn was knitted into products such as socks and finished with dyeing,
A phenomenon occurred in which the product itself contracted significantly. For this reason, conventionally, when knitting, the knitting length has been set to be long by an amount corresponding to this shrinkage. [Problems to be Solved by the Invention] Therefore, in order to solve the problem of increased torque that accompanies improvement in covering properties, the present invention significantly increases the number of twists in the inner covering,
It is possible to reduce the torque without reducing the number of outer covering twists, and to have sufficient covering twist to exhibit high coverage and a uniform appearance, yet still exhibit sufficiently low torque characteristics, and in addition, the covering process One objective is to provide an excellent nylon 66 coated elastic yarn that can be produced without significantly reducing the production rate. That is, one object of the present invention is to obtain a knitted fabric that has excellent coverage and uniformity, is easy to knit, and has a beautiful knitted surface, and can be produced without reducing the production speed in the covering process. Our objective is to provide a nylon 66 coated elastic yarn that can be used. Another objective is to reduce the amount of yarn used in the manufacture of final products by significantly suppressing the shrinkage that occurs during the dyeing process after producing coated elastic yarns or after producing products such as socks. That is, the object of the present invention is to provide a nylon 66-covered elastic yarn that can reduce the braid length when manufactured into a product. [Means for Solving the Problems] In order to achieve this object, the present invention provides a double-layer fabric made by wrapping a nylon 66 covering yarn twice around a core yarn made of elastic fibers in different twist directions. In the heavy-covered elastic yarn, both the outer wrapping and the inner wrapping of the covering yarn are made of nylon 66 double-covered elastic yarn made of nylon 66 long fibers having a Young's modulus of 15 to 22 g/d. The elastic fibers used in the present invention are preferably polyurethane elastic fibers commonly referred to as spandex fibers, but may be other types of elastic fibers. On the other hand, the long fibers constituting the covering yarn are nylon 66 fibers, which have excellent dyeing properties, mechanical strength, friction resistance, etc. and are suitable for the covering yarn.
A fiber having a Young's modulus of ~22 g/d, more preferably a boiling water shrinkage of 8% or less, is used. This fiber, for example,
It can be obtained by high-speed spinning at a low speed, or by drawing at a low speed and then drawing at a low magnification. In addition, the nylon 66 fiber referred to in the present invention only needs to have a polymer component that is substantially a nylon 66 unit, and may contain a copolymer component to an extent that does not impede the properties of nylon 66, for example, about 5% or less. Good too. [Function] The present invention uses conventional nylon 66 to reduce torque without reducing coverage or uniformity.
Nylon 66 long fibers having a Young's modulus of 15 to 22 g/d are used as the covering yarn, which has a Young's modulus significantly lower than that of the nylon 66 fiber of the covering yarn in the covered elastic yarn. In double-covered elastic yarns, the twist directions are reversed between the inner and outer windings, so that the torques due to the covering twists cancel each other out between the inner and outer windings. However, conventionally, nylon 66 long fibers with a high Young's modulus (for example, about 27 to 29 g/d) were used as the covering yarn, so even if the number of covering twists of the outer covering yarn was lowered, the resulting torque was considerably large, and it was difficult to completely offset both torques under conditions that provided sufficient coverage. As a result, in the conventional double-covered elastic yarn, the torque due to the outer covering twist appears as the torque of the covered elastic yarn. This torque can be reduced by significantly reducing the number of twists in the outer covering, but
At the same time, there is a drawback that the coverage is reduced and the appearance is impaired. On the other hand, it can be reduced by significantly increasing the number of twists in the inner covering, but at the same time there is a drawback that the production speed of the covering is significantly reduced. Therefore, we investigated ways to reduce the torque of the covered elastic yarn without significantly lowering the number of twists in the outer covering or increasing the number of twists in the inner covering.We found that fibers with a low Young's modulus were used as the covering yarn. The present invention was developed based on the knowledge that this is effective for reducing torque. In the present invention, since nylon 66 fibers having a Young's modulus of 15 to 22 g/d are used as the covering yarn used on the outside where large torque is generated, the helical bending stress due to the outer covering twist is low. Torque can be reduced without reducing the number of twists in the outer covering. 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. That is, in general, the production speed of double-covered elastic yarn is determined by the number of inner covering twists, which has a higher number of twists, and the number of outer covering twists is determined by the number of covering twists, which is lower, even at the expense of coverage for torque generation. However, according to the present invention, a coated elastic yarn with excellent coverage and uniformity and low torque can be obtained without reducing productivity. In order to obtain these effects, the Young's modulus of the nylon 66 fibers of the coating yarn must be 22 g/d or less, and preferably 21 g/d or less. This Young's modulus is practically required to be 15 g/d or more in order to handle the yarn in the covering process and to obtain the strength and elongation characteristics necessary for the covering yarn. Nylon 66 long fibers having such a Young's modulus level can be obtained by a high-speed spinning method at about 3,500 to 6,000 m/min, or by a method of drawing at a low speed and then drawing at a low magnification. Among these, fibers produced by high-speed spinning are preferred because of their excellent uniformity of yarn quality. Fibers obtained by these methods are generally
Although it is called an intermediately oriented yarn, in order to use it as a covering yarn, spinning conditions such as spinning speed and polymer viscosity are set so that the Young's modulus level is 22 g/d or less. The Young's modulus of the covering yarn in the present invention is determined by leaving the covering yarn under free shrinkage in an environment of 20°C x 65% RH for 24 hours, using a Tensilon tensile tester at an initial load of 1/30 g/d, The stress at 3% elongation of the S-S curve drawn at a test length of 20 cm and a tensile speed of 20 cm/min is 100/3.
This is the value obtained by multiplying the In addition, nylon 66 intermediately oriented yarns with a Young's modulus of 22 g/d or less generally tend to have a lower boiling water shrinkage rate than conventional drawn yarns, so it is important to note that nylon 66 intermediately oriented yarns with a Young's modulus of 22 g/d or less tend to have a lower shrinkage rate in boiling water than conventional drawn yarns. It is also effective in suppressing shrinkage during dyeing and finishing. In order to suppress this shrinkage, it is preferable to use fibers having a boiling water shrinkage rate of 8% or less. Furthermore, the yarn fineness D ₂ of the outer wrapping yarn and the yarn fineness D 1 of the inner wrapping yarn and the yarn fineness D ₁ are about the same as in the case of the conventional double-covered elastic yarn. , for example, D ₁ +D ₂ = about 12 to 50 deniers. In order to improve coverage, it is preferable that the yarn fineness of these fibers satisfies D ₁ <D ₂ , and more preferably D ₂ /D ₁ ≧1.5. Also,
In order to improve the covering properties, non-circular cross-section fibers may be used, especially as the outer covering yarn. The covering twist number T ₂ of the outer covering yarn may be, for example, about 1500 to 3500 t/m. On the other hand, the number of covering twists T ₂ of the outer covering yarn is preferably equal to or less than the covering twist number T ₁ of the inner covering yarn, and for example, T ₂ /T ₁ may be about 0.85 to 1.00. In the present invention, since the Young's modulus of the covering yarn is low, the torque due to the covering twist can be suppressed to a small level, so even within the range of the number of covering twists, a relatively low inner covering twist with T ₂ /T ₁ of 0.9 or more can be used. This twist number condition is preferable for improving productivity. The production of covered yarn, in which the covering yarn is wound around the core yarn, is carried out by the usual method of manufacturing covered yarn, that is, the two covering yarns are sequentially wound outward in a double manner by changing the twisting direction around the core yarn. This can be done by double coating. [Example and Comparative Example] A 20-denier, 3-filament spandex fiber yarn was stretched 3.2 times and spindle rotation was performed for first twist (inner covering twist) using a normal covering machine (maximum spindle rotation speed 16,000 rpm). Double covering (first twist in the Z direction, first twist in the S direction) was performed at a speed of 16,000 rpm. The coating yarn used in this case was a nylon 66 filament yarn of 15 denier and 5 filaments, and its Young's modulus and boiling water shrinkage were as shown in Table 1. In addition, the nylon 66 yarn with a Young's modulus of 28.0 g/d is a drawn yarn obtained by drawing in a normal method,
On the other hand, nylon 66 yarn with a Young's modulus of 19.5 g/d
21.5g/d nylon 66 yarn means polymer viscosity
Nylon 66 with a titanium content of 2.62 and 0.3%
Polymer is melt-spun at 290℃, cooled and oiled in the usual way, and spun at 4500m/min or 4200m/min.
This is an intermediately oriented yarn obtained by a high-speed spinning method in which the yarn is controlled by a roller and wound into a package. The torque value of the obtained covered elastic yarn is determined by applying a load of 1 g to the center of a 1 m long coated elastic yarn and letting it hang down to develop torque, and then calculating the number of twists (number of twists per 50 cm). It is measured and converted to the number of twists per meter. The quality of the torque was evaluated based on the following criteria. ◎: Excellent △: Slightly poor ○: Good ×: Poor Covering productivity was also evaluated using the same criteria as above. Furthermore, a sock fabric was knitted with the obtained covered elastic yarn, and the coverage and uniformity of the knitted sock fabric obtained by dyeing and finishing were evaluated visually using a magnifying glass according to the following criteria. (relative evaluation). ○: Good △: Slightly poor ×: Poor This sock knitted fabric was knitted with a basis weight so that the horizontal elongation dimension after dyeing was the same.

[Table] As can be seen from the results in Table 1, in the case of the conventional method using filament yarn with a high Young's modulus as the covering yarn (Comparative Examples 1, 2, 3, and 4), the number of twists of the outer covering was If it is high, the covering performance is good, but it has the disadvantage of high torque under the conditions that satisfy the covering productivity.Also, if the inner covering twist number is increased to 2750t/m and the torque is lowered, the covering productivity is Since the speed is significantly reduced to a level that is difficult for industrial production, it has been difficult to improve the torque without reducing covering productivity. On the other hand, as in Comparative Example 4, when the torque was improved by lowering the number of twists in the outer covering, there was a problem in that the covering properties and uniformity deteriorated. On the other hand, in Examples 1, 2, and 3 according to the present invention, the torque is reduced without significantly lowering the number of twists in the inner covering or increasing the number of twists in the outer covering, resulting in improved coverage and low torque. A coated elastic yarn with excellent properties and uniformity could be produced with high productivity. Furthermore, since the coated elastic yarn according to the present invention has small shrinkage during dyeing and finishing, in the case of Example 2, the sock knitted fabric with the same horizontal elongation dimension was made with approximately 8% less yarn length than the conventional (Comparative Example 3). was able to manufacture. In this case, approximately 15% of the increase in covering production speed
Together with this, the productivity improvement due to the present invention is approximately
It was 23%. [Effects of the Invention] Since the nylon 66 double-covered elastic yarn according to the present invention uses nylon 66 long fibers with a low Young's modulus as the covering yarn, the number of outer covering twists can be lowered to improve coverage and uniformity. It is possible to reduce the torque of the obtained covered elastic yarn without causing deterioration or significantly increasing the number of inner covering twists and reducing productivity. Therefore, it is possible to obtain an excellent coated elastic yarn that has high coverage, a uniform appearance, and low torque characteristics, and can be manufactured with high productivity suitable for industrial production. . Furthermore, this nylon 66 coated elastic yarn has a low shrinkage rate in boiling water, is easy to knit, and can significantly reduce the basis weight during knitting, so it has good covering properties.
It is useful for obtaining a knitted fabric with a beautiful knitting surface, and can also reduce the amount of yarn used during knitting.

Claims (1)

[Scope of Claims] 1. In a nylon 66 double-coated elastic yarn formed by wrapping a nylon 66 coating yarn twice around a core yarn made of elastic fibers with different twisting directions, the outer side of the coating yarn 15 for both wrapping and inner wrapping
A nylon 66 double coated elastic yarn characterized in that it consists of nylon 66 long fibers having a Young's modulus of ~22 g/d. 2. The double coated nylon 66 elastic yarn according to claim 1, wherein the nylon 66 long fibers have a boiling water shrinkage rate of 8% or less. 3 The number of covering twists of the outer wrapping yarn is
Claim 1, characterized in that the number of twists of the covering yarn wrapped inside is 0.9 times or more.
Nylon 66 double coated elastic thread as described in Section 1.