JPH0252018B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention is directed to a double covered elastic yarn (also simply referred to as a covered elastic yarn), which is made by doubly wrapping thermoplastic synthetic fiber yarn such as polyamide around an elastic yarn such as polyurethane yarn. Regarding improvements. In particular, the present invention relates to a coated elastic yarn useful as a material for socks, stockings, and the like. [Prior art] By double wrapping thermoplastic synthetic fibers such as polyamide long fibers around elastic threads such as polyurethane threads (double covering), the dyeing properties and mechanical strength, which are disadvantages of elastic threads, can be improved. It is widely used to cover friction resistance and other properties.
This double covered coated elastic yarn has 20 to 70
It is generally manufactured by wrapping a covering thread of 70 to 20 deniers twice around a denier elastic yarn.
Wrapping was carried out at a rate of about 1800t/m (Japanese Patent Laid-Open No. 1973)
-19146), socks, stockings, etc.). As the covering thread, the same yarn made of the same long fibers was used for both the inner wrapping and the outer wrapping. 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.
Increase it to around 3000-4000t/m, and
It is necessary to increase the number of single threads of the covering thread. However, if the number of wrappings of the covering thread is increased,
This will significantly reduce the production speed, and furthermore, the torque of the resulting covered elastic yarn will increase, making it more likely that snarls will occur during knitting, and the resulting knitted fabric will have more irregular stitches. There is. Furthermore, increasing the number of single yarns for the covering yarn requires the use of ultra-fine single yarns, but these ultra-fine single yarns are not easy to spin, are expensive, and cannot be used for practical purposes. Moreover, there is a problem in that fuzz is likely to occur during winding. As described above, each method has its advantages and disadvantages, and is not preferred for industrially obtaining coated elastic yarns with a fineness. [Problems to be Solved by the Invention] Therefore, the present invention solves the above-mentioned problems by increasing the number of windings of the covering yarn, and by increasing the yarn fineness sum (total) of the inner and outer covering yarns. One object of the present invention is to provide a covered elastic yarn that can provide sufficiently high coverage without increasing the fineness. That is, one object of the present invention is to provide a covered elastic yarn that can sufficiently improve the covering properties without impeding the yarn fineness of the covered elastic yarn and has good productivity. Another object of the present invention is to provide an excellent covered elastic yarn that reduces the torque of the covered elastic yarn, is easy to knit, and can yield a knitted fabric with a beautiful knitted surface. [Means for Solving the Problems] In order to achieve this object, the present invention is formed by doubly wrapping a covering thread made of long fibers of a thermoplastic polymer around a core thread made of elastic fibers. The covered elastic yarn is characterized in that the single fiber fineness of the long fibers constituting the covering yarn wound on the outside is 0.8 times or less of the single filament fineness of the long fibers forming the covering yarn wound on the inside. Made of double covering elastic yarn. 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, 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. [Function] In order to improve coverage and reduce torque, the present invention uses two types of covering yarns with different filament finenesses of 1:0.8 or less of the long fibers, and a yarn with a thick single filament fineness among them. It is characterized by winding the yarn with the smaller fineness on the inside, and the yarn with the smaller fineness on the outside. On the other hand, conventionally, both the inner covering yarn and the outer covering yarn use the same yarn consisting of long fibers having the same single yarn fineness and the like. However, there is a difference in the covering efficiency of the core yarn between the inner covering yarn and the outer covering yarn, and the covering efficiency of the outer covering yarn is considerably higher than that of the inner covering yarn. From this, we learned that it is important to increase the coverage of the outer-wrapped covering yarn in order to improve the coverage of the resulting covered elastic yarn, and that the torque of the coated elastic yarn increases the covering of the outer-wrapped covering yarn. The present invention was based on the knowledge that this is caused by the torque caused by twisting. In the present invention, as the covering yarn used for the outer side with good covering efficiency, a yarn with a fineness of fineness d ₂ of which is 0.8 times or less than the single yarn fineness d ₁ of the inner wrapping yarn and high covering ability is used. Therefore, the covering properties can be improved without increasing the number of covering twists or increasing the fineness of the covering yarn to increase the diameter of the covering elastic yarn. In general, with double-covered elastic yarns, trouble occurs during knitting due to the generation of torque, so the number of twists in the outer covering must be reduced to approximately 0.7 to 0.8 times the number of twists in the inner covering. However, in the method of the present invention, the number of twists in the outer covering Even if the number of covering twists is set to 0.9 times or more of the inner twist value to improve coverage without impeding productivity, it is still possible to show low torque as a covered elastic yarn. As a result, the covering properties can be improved without impeding the thinness or productivity of the obtained covered elastic yarn, that is,
A coated elastic yarn with excellent thinness and covering properties can be obtained with high productivity. In addition, in the case of a covered elastic yarn that has the same level of coverage and torque as the conventional method, the number of inner twists, which restricts the covering production speed due to the high number of covering twists, can be lowered to increase the covering speed. It is also possible to significantly improve productivity during covering. In addition, since the single yarn fineness of the outer covering yarn is small, the helical bending stress due to the covering twist of the outer wrapping yarn is reduced, and as a result, the torque of the covering elastic yarn is reduced, causing problems during knitting. This means that defects in the knitting surface and knitting surface can be improved. In order to obtain these effects, the difference in single yarn fineness d ₂ /d ₁ must be 0.8 times or less,
Furthermore, it is preferably 0.75 times or less. However, if the single yarn of the outer wrapped yarn is too thin compared to the single yarn of the inner wrapped yarn, there will be a lot of fuzz during production and it will be difficult to spin the yarn. The single yarn fineness is preferably 0.7 denier or more. In addition, the yarn fineness of these outer covering yarns
D ₂ and the inner wrapping covering yarn and yarn fineness D ₁ are:
It is sufficient that the sum of these values is about the same as in the case of conventional double-covered elastic yarns, for example, about D ₁ +D ₂ =15 to 50 deniers. In order to further improve the covering properties, it is preferable that the yarn fineness of these fibers satisfies D ₁ <D ₂ , and more preferably D ₂ /D ₁ ≧1.5. Furthermore, in order to further 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. The number of covering twists T ₂ of the outer covering yarn is equal to the number of covering twists of the inner covering yarn in order to keep the torque low.
It is preferable to make T smaller than ₁ , for example,
It is sufficient if T ₂ /T ₁ is about 0.75 to 0.95. In the present invention, since the single yarn fineness of the outer covering yarn is made small, the torque is low, and it is also possible to apply a relatively high covering twist with T ₂ /T ₁ of 0.9 or more to the outside. 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 twist direction outward. This can be done by attaching a double covering. [Example and Comparative Example] A 20 denier, 3 filament spandex fiber yarn was stretched 3.2 times and double covered using a normal covering machine (lower twist Z direction, upper twist S direction).
direction). The covering yarn used in this case and its covering conditions are as shown in Table 1. For the covering yarn, two types of nylon 6 filament yarns with different yarn finenesses were used in combination. , the number of single yarns and the number of covering twists were varied. The coverage of the obtained covered elastic yarn was evaluated visually using a magnifying glass according to the following criteria. ◎: Excellent △: Slightly poor 〇: Good ×: Poor In addition, the torque value of the obtained covered elastic yarn was determined by applying a load of 1 g to the center of a 1 m long coated elastic yarn and letting it hang down. express,
Measure the number of twists that occurred (number of twists per 50 cm), and
It is converted into the number of twists per m. The quality of the torque was evaluated using the same criteria as in the case of the coverage. Furthermore, productivity was evaluated in terms of yarn spinning performance when producing covering yarn and occurrence of fuzz and yarn breakage during double covering. The evaluation was written using the same symbols as in the case of the above-mentioned coatability.

【table】

[Table] As can be seen from this result, in the case of the conventional method using the same yarn with the same single yarn fineness and yarn fineness (Comparative Examples 1, 2, and 3), the single yarn fineness was made finer, By increasing the number of single yarns, coverage and torque can be improved, but conversely, fuzzing and yarn breakage increase, and the spinning performance deteriorates, resulting in poor productivity. In contrast, Examples 1, 2, and 3 according to the present invention
With the coated elastic yarn, the covering properties and torque were improved without reducing productivity, and both the covering properties, low torque properties, and productivity were excellent. Further, in Example 3, even if the total fineness was reduced to 25 deniers, covered elastic yarn with excellent covering properties could be obtained with good productivity without increasing the number of twists. On the other hand, when the single yarn fineness of the outer covering yarn was made thicker than the single yarn fineness of the inner covering yarn, the torque significantly increased, contrary to the present invention (Comparative Example 4). [Effects of the Invention] The double covering elastic yarn according to the present invention uses a covering yarn with a high covering effect and wrapping it on the outside with a high covering efficiency. The coverage can be improved without increasing the amount. Therefore,
A coated elastic yarn with good productivity and excellent coating effect can be obtained. Furthermore, since only the single yarn of the outer covering yarn is made thinner, torque can be improved without impeding productivity. Furthermore, coverage can be improved by reducing only the fineness of the single yarn of the outer wrapped yarn (to 0.8 times or less than the single yarn fineness of the inner wrapped yarn), so it is also possible to improve coverage when obtaining thin covered elastic yarns. The invention is valid. For example, it is possible to improve the covering properties of high-grade coated elastic yarns having a total fineness of 30 deniers or less, and to produce fine-grained coated elastic yarns with excellent covering properties with good productivity.

Claims (1)

[Claims] 1. In a double covering elastic yarn formed by doubly wrapping a covering yarn made of long fibers of a thermoplastic polymer around a core yarn made of elastic fiber, the long fibers forming the covering yarn wound on the outside are The single yarn fineness is the single yarn fineness of the long fibers that make up the covering yarn wrapped inside.
Double covering elastic yarn characterized by less than 0.8 times.