JPH0461099B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to nylon 6, which is made by doubly wrapping nylon 6 long fiber yarn around an elastic thread such as polyurethane.
Concerning improvements in double-covered elastic yarns. In particular, the present invention relates to a nylon 6-coated elastic yarn useful as a material for socks, stockings, and the like. [Conventional technology] Nylon 6 is wrapped 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 double wrapping a 70-20 denier straight nylon covering yarn around a 20-70 denier elastic yarn, for example, by twisting the lower thread. Winding is carried out at a rate of several 2,600 t/m and a twisting rate of 1,800 t/m.
47-19146), socks, stockings, etc. In addition, covered elastic yarn, which is made of straight nylon long fibers (also called flat yarn) that have not been crimped, is not sublime, has high transparency, and has a smooth knitted surface. Since a beautiful knitted fabric can be obtained, it is suitably used for 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 covered elastic yarn itself cannot be increased, it is necessary to increase the coverage of the covering yarn. 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, if the number of windings of the covering yarn is increased in this way, there is a 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 6 filaments as coating threads, conventionally, so-called drawn threads (14-
(Has a high boiling water shrinkage rate of about 15%) was used to manufacture coated elastic yarn, so when this coated elastic yarn was used to knit and dye products such as socks,
A phenomenon occurred in which the product itself contracted significantly. For this reason, conventionally, the knitting length has been set to be long to correspond to this shrinkage during knitting. [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 6-coated elastic yarn that can be produced without significantly reducing production speed. That is,
One object of the present invention is to have excellent coverage and uniformity,
Another object of the present invention is to provide a nylon 6-covered elastic yarn that is easy to knit, provides a knitted fabric with a beautiful knitted surface, and can be produced without reducing the production speed in the covering process. 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 6-covered elastic yarn that can reduce the braid length when manufactured into a product. [Means for Explaining the Problems] In order to achieve this object, the present invention has developed a double-layer fabric made by wrapping a covering yarn of nylon 6 twice around a core yarn made of elastic fibers in different twist directions. In the heavily covered elastic yarn, both the outer wrapping and the inner wrapping of the covering yarn are made of straight nylon 6 long fibers having a Young's modulus of 12 to 18 g/d,
and the yarn fineness (D ₂ ) and the number of covering twists (T ₂ ) of the covering yarn wound on the outside, the yarn fineness (D ₁ ) of the covering yarn wound on the inside, and the number of covering twists (T _{1 )} . ) is the following formula (1) to (3) D ₁ + D ₂ = 12 to 50 denier...(1) T ₂ = 1500 to 3500 t/m...(2) T ₂ /T ₁ = 0.85 to 1.00...(3) It is made of nylon 6 double coated elastic yarn that satisfies the following requirements at the same time. The elastic fibers used in 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, even if the long fibers forming the covering yarn are straight fibers of nylon 6, which has excellent dyeing properties, mechanical strength, abrasion resistance, etc. and is suitable for the covering yarn, A fiber having a Young's modulus of , and more preferably a water conduction shrinkage rate of 11% or less is used. This fiber is, for example, 3500
By spinning at high speed of ~6000m/min,
Alternatively, it can be obtained by drawing at a low speed and then drawing at a low magnification, and is a straight nylon 6 long fiber that has not been crimped or the like. In addition, the nylon 6 fiber referred to in the present invention is
The polymer component only needs to be substantially nylon 6 units, and may contain a copolymer component to an extent that does not impair the properties of nylon 6, for example, about 5% or less. [Function] The present invention uses conventional nylon 6 to reduce torque without reducing coverage or uniformity.
Covering yarn in covered elastic yarn Nylon 6 long fibers, which have a Young's modulus significantly lower than that of nylon 6 fibers and have a Young's modulus of 12 to 18 g/d, are used as the covering yarn. In the double-covered elastic yarn, since the twisting directions are reversed between the inner winding and the outer winding, the torques due to the covering twists are in a relationship that cancels each other out between the inner and outer windings. However, conventionally, nylon 6 long fibers with a high Young's modulus (for example, about 24 to 26 g/d) were used for the covering, 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, nylon 6 fibers having a Young's modulus of 12 to 18 g/d are used as the covering yarn used on the outside where a large torque is generated, so 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 6 fibers of the coating yarn must be 18 g/d or less, and preferably 17 g/d or less. The Young's modulus is practically required to be 12 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. Such straight nylon 6 long fibers having 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. The fibers obtained by these methods are generally referred to as intermediately oriented yarns, but in order to be used as coating yarns, spinning conditions such as spinning speed and polymer viscosity are set so that the Young's modulus level is 18 g/d or less. and spin it into yarn. 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 6 intermediately oriented yarns with a Young's modulus of 18 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 6 intermediately oriented yarns with a Young's modulus of 18 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 with a boiling water shrinkage rate of 11% or less. Thread fineness (D ₂ ) of these outer covering yarns
The sum of the inner wrapping covering yarn and the yarn fineness (D ₁ ) is about the same as that of the conventional double covering elastic yarn, that is, D ₁ +D ₂ =12 to 50 deniers. If the yarn fineness sum is so thick as to exceed 50 deniers, it is difficult to obtain a thin coated elastic yarn suitable for stockings, etc. In order to improve coverage, the yarn fineness of these
It is preferable that D ₁ <D ₂ and furthermore, D ₂ /D ₁ ≧
It is preferable to set it to 1.5. Furthermore, in order to improve the covering properties, non-circular cross-section fibers may be used, especially as the outer covering yarn. The number of covering twists (T ₂ ) of the outer covering yarn is:
It is 1500-3500t/m. The value (T ₂ /T ₁ ) of the number of covering twists (T ₂ ) of the outer covering yarn and the number of covering twists (T ₁ ) of the inner covering yarn is 0.85 to
It is 1.00. These twist number conditions are necessary for production without reducing the production speed in the covering process. 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 value. This twist number condition is preferable for further 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 producing covered yarn, that is, the two covering yarns are wound twice around the core yarn by sequentially changing the twisting direction to the outside. This can be done by double covering. [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 covering yarn used in this case was a 15-denier 5-filament nylon 6-filament yarn, and its Young's modulus and boiling water shrinkage were as shown in Table 1. In addition, the nylon 6 yarn with a Young's modulus of 24.5 g/d is a drawn yarn obtained by drawing in a normal method,
On the other hand, nylon 6 yarn with a Young's modulus of 17.0 g/d is obtained by melt spinning a nylon 6 polymer with a polymer viscosity of 2.62 and a titanium oxide content of 0.3% at 265°C.
This is an intermediately oriented yarn obtained by a high-speed spinning method, which is cooled and lubricated in the usual manner, taken up by rollers at 4200 m/min, and wound into a package. The torque value of the obtained covered elastic yarn is calculated 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 using the harvested 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 using the following criteria. (based on relative evaluation). ○: Good △: Slightly poor This sock knitted fabric was knitted with a basis weight so that the horizontal elongation dimension after dyeing was the same.

【table】

[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 coverage is good, but it has the disadvantage of high torque under 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 production speed will be reduced. Since the torque decreases significantly 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 is improved by lowering the number of twists in the outer covering, there is a problem in that coverage and uniformity deteriorate. On the other hand, in Examples 1 and 2 according to the present invention,
Manufacture coated elastic yarn with reduced torque and excellent covering properties, low torque properties, and uniformity at high productivity without significantly lowering the number of inner covering twists or increasing the number of outer covering twists. I was able to do that. Furthermore, since the coated elastic yarn according to the present invention has a small shrinkage during dyeing and finishing, in the case of Example 2, the yarn length was approximately 7% less than that of the conventional (Comparative Example 3), and the sock knitting with the same horizontal elongation dimension was performed. was able to manufacture soil.
In this case, the increase in production rate of the covering is approximately 15
%, the productivity improvement due to the present invention is:
It was about 22%. [Effects of the Invention] Since the nylon 6 double-covered elastic yarn according to the present invention uses nylon 6 long fibers with a low Young's modulus as the covering yarn, the number of outer covering twists is lowered and coverage and uniformity are deteriorated. Furthermore, the torque of the resulting covered elastic yarn can be reduced without significantly increasing the number of twists in the inner covering and reducing productivity. Therefore, it is possible to obtain a thin and excellent coated elastic yarn that has high covering properties, a uniform appearance, low torque characteristics, and is suitable for stockings, etc., and has high productivity suitable for industrial production. It can be manufactured in Furthermore, this nylon 6-covered 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 double-covered elastic yarn formed by wrapping a covering yarn of nylon 6 twice around a core yarn made of elastic fibers with different twisting directions, the outer wrapping of the covering yarn is 12 to 18 g/d for both inner and inner wrapping
It is made of straight nylon 6 _long fibers having _a Young's modulus of The yarn fineness (D ₁ ) and the number of covering twists (T ₁ ) are calculated using the following formulas (1) to (3) D ₁ + D ₂ = 12 to 50 denier...(1) T ₂ = 1500 to 3500 t/m...(2 ) T ₂ /T ₁ = 0.85 to 1.00...(3) A nylon 6 double-covered elastic yarn. 2. The nylon 6 double-covered elastic yarn according to claim 1, wherein the nylon 6 long fibers have a boiling water shrinkage rate of 11% or less. 3. The value ( _T2 / _T1 ) of the number of covering twists ( _{T2 )} of the covering yarn wound on the outside relative to the number of covering twists (T1) of the covering yarn wound on the inside is 0.9 to 1.00. A nylon 6 double coated elastic yarn according to claim 1, characterized by: