JPS62250239A - Low revolving coated elastic yarn and its production - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a false-twist coated elastic yarn and a method for producing the same, and more specifically, it has excellent covering properties, low turning torque, and when used in jersey knitted fabrics. However, the present invention relates to a false-twist coated elastic yarn with a small diagonal knitted fabric and a rational manufacturing method thereof.

[Prior art and problems to be solved by the invention] The coated elastic yarns that are currently widely used have a core made of elastic yarns such as rubber yarns or polyurethane elastic fibers, and other short fiber rovings are twisted around this core. There are core spun yarns entangled with each other, or elastic yarns such as polyurethane elastic fibers as a core, and covered with other long and short fiber yarns by twisting, or covering yarns made by pulling these yarns together and twisting them together. . Furthermore, in the turbulent region of the jetted fluid, it is possible to use elastic threads such as rubber threads or polyurethane elastic fibers as a core, and to disturb and entangle other long fibers, or to align elastic threads and thermoplastic filament threads. There are thread-twisted yarns that are crimped as a set.

However, although each of these yarns has its own merits, it also has the following drawbacks. First, a hollow spindle rotates with a cover bobbin made of inelastic yarn, and is wound around the stretched rubber or polyurethane elastic fiber passed through the spindle, or in a ring twisting machine, the inelastic yarn is wrapped around the stretched rubber or polyurethane elastic fiber. So-called single covered yarns, which are made by combining and twisting polyurethane elastic fibers, have fairly good coverage, but the twisting torque is strong and the stretching power is larger than necessary, so they are often used to fix the twisting torque and reduce the power. In addition, there is a natural limit to the spindle rotation speed, and the productivity calculation for 90 denier cotton yarn has a spindle rotation speed of 110.
Even if 00Orp and heating number of 500 times/m are used, the processing speed is 2
It never exceeded 0m/win.

In addition, the polyurethane elastic yarn under elongation and other long fiber yarns are passed through a jet fluid turbulence area, and the other fibers are disturbed and entangled around the polyurethane elastic yarn.The cover yarn is twisted. Since the threads are not twisted, the entangling properties are poor, the core thread may be exposed, and the air cost is relatively high. Although it has good properties, it still requires the usual twisting process, so its productivity is no better than single covered yarn, and the number of processing steps increases, making it expensive, so it is rarely used. .

That is, as mentioned above, the conventional techniques relating to coated elastic yarns include those that have real twist or have poor entanglement properties due to fluid disturbance, and there has been no one that can be called a non-twist coated elastic yarn.

False-twisted coated elastic yarns are made by processing elastic yarns and thermoplastic synthetic filament yarns in a core/sheath shape and twisting them into a composite plate, and the elastic yarns are crimped multifilament yarns that are essentially untwisted to form a core/sheath. This is a technique that covers the sheath. However, in the past, elastic thread was used as the core.
In order to restrain the core yarn with the false-twisted crimped yarn, the core yarn is elongated, and a low tension (0) is applied so that the non-crimped multifilament fibers that form the sheath can easily be arranged around the core yarn as if wrapping around the outside. ,001~0.004 g/d tension), the core yarn and sheath yarn are aligned and supplied to the false twisting area, and then heated using a nip roller, guide, etc. between the supply roller and the false twist heater. Do not let it start suddenly, or
Alternatively, it is possible to arrange the core/sheath using a U-shaped or V-shaped groove guide near the heating start point to align the elastic yarn and sheath yarn fibers, and then immediately introduce the yarn to the false twisting area. Instead, the idea was to keep the core threads aligned for a certain period of time to suppress the propagation of heat twisting and thereby insert the core threads into the sheath threads.

However, in order to obtain good coverage, it is necessary to increase the false twisting temperature and partially fuse the thermoplastic fiber threads of the sheath yarn, thereby strengthening the action of the sheath yarn to restrain the core yarn. there were. As a result, the resulting knitted fabric has a reduced elongation recovery strength due to deterioration of the elastic yarn, and the supplied thermoplastic fiber yarn is
Since it is a multifilament yarn without crimps, the sheath yarn crimped yarn of the obtained covered elastic yarn has the turning torque of normal false twisted yarn, and such conventional covered elastic yarn is not suitable for jersey knitted fabrics. It is knitted and heat lux treatment is #! When applied, the knitted fabric appears to be slanted due to the large turning torque. In addition, a snarl structure occurs in the single fiber filaments of the false-twisted crimped multifilament yarn that constitutes the sheath portion due to the turning torque, and the appearance of the knitted fabric has the disadvantage that it becomes uneven due to the occurrence of snarl knobs. . Furthermore, according to the prior art, it is necessary to supply the sheath thread tension at a very low tension before supplying it.
Variations in this supply tension (0,0014 to 0.004 g/d), variations in the core/sheath arrangement due to the U-shaped and ■-shaped guides after supply, and variations in the guide effect that suppresses the propagation of heating distortion during false twisting. This results in variations in coverage,
Furthermore, when high-temperature false-twisting processing in which the sheath yarns are subjected to filament fusion in order to improve coverage, there is a problem in that the dyeability of the sheath yarns also increases.

The present invention is a coated elastic yarn with excellent covering properties, no deterioration of the elastic yarn, excellent elongation recovery properties, and low turning torque, and which provides a rational and diagonal stable knitted fabric made using the yarn. The purpose is to provide a manufacturing method.

[Means for solving problems]

The above-mentioned object of the present invention is to provide a covered elastic yarn having a polyurethane elastic fiber as a core yarn and a low-turning false twisted crimped yarn made of a thermoplastic fiber multifilament yarn as a sheath yarn,
), the core yarn is located approximately at the center of the covered elastic yarn, and the sheath fibers are twisted to cover the core yarn so as to uniformly wrap the outer periphery of the core yarn; Each single fiber of the swirlable false-twisted crimped yarn intermittently and randomly reverses its twisting direction in the length direction and intertwines with the core yarn, causing the single filaments of the core yarn and sheath yarn to stick together partially. and maintain convergence, and the degree of confounding is at least 80%, ■.

Each single filament constituting the core yarn and the sheath yarn is arranged in the yarn axis direction in a substantially untwisted state, (4)
When the composite yarn is relaxed by 50% from the tensioned state after dry heat relaxation treatment at 90°C for 10 minutes, the length of the snarl filament loop formed by the single fibers of the sheath-like multifilament is 1 fl or less. This is achieved by a coated elastic yarn with a characteristic low swirl.

To produce the above-mentioned low-twirl coated elastic yarn, polyurethane elastic fibers and thermoplastic false-twisted crimped multifilament yarns in an elongated state are simultaneously fed to a false-twisting device, and at that time, the direction of the false-twisting heating is It is preferable to use a manufacturing method in which heating, heat fixing, and untwisting are performed in a continuous manner so that the following conditions are satisfied, with the direction of heating being opposite to the direction of false twisting and heating of the false twisted crimped multifilament yarn in the supply system.

■　0.7T+≦T2≦1.2T.

■ T-+ 70 "C≦tl;!i;T120"
C■ 170℃≦Lz≦T,%z 10'CTI
; Number of false twists (-number of plate twists) of the false twisted crimped yarn to be supplied, T2; Number of false twists during composite false twisting (number of secondary false twists), t;; Twist number (-plate twisting heater temperature), t2; false twist number during composite false twisting (secondary false twist number), twisting heater temperature), T Ph I; melting point of thermoplastic multifilament yarn, T1; Melting point of polyurethane elastic fiber, D: denier of thermoplastic multifilament.

The present inventors have discovered that in a composite false-twisting method of elastic yarn and inelastic thermoplastic multifilament yarn, which is a method for producing false-twisted coated elastic yarn, the elastic yarn forms a core yarn to firmly restrain the core yarn. As a result of repeated consideration of the formation of a core/sheath structure between the yarn feeding roller and the false twisting heater, we found that a composite plate of conventional elastic yarn and non-crimped multifilament yarn that serves as the sheath yarn was developed. In the twisting process, the opening of the sheath yarn immediately after the false twisting yarn feeding roller is small, and (because the fiber packing density of the heated sheath yarn is high), the elastic yarn cuts into the inside of the sheath yarn, causing the core/sheath to separate. It has been found that it is difficult to form an array and that the resulting elastic yarns have insufficient coverage. To improve this, it is necessary to improve the fiber opening immediately after the yarn feeding roller (
As a result of considering a sheath yarn with good opening properties, we decided to use a false twisted crimped yarn and We discovered that by applying the composite plate twisting process in the opposite direction to the false twisting direction, the opening of the sheath yarn immediately after the yarn feeding roller was increased, and the effect of forming the core/sheath arrangement was increased. Thus, the present invention has been achieved. The reason why the action of wrapping the core yarn by the sheath yarn became greater is considered to be that the torque force was increased after the sheath yarn was crimped immediately after the supply roller. In addition, in order to improve the opening property of the sheath yarn immediately after the yarn feeding roller, it is preferable that the heating tension in the composite plate twisting process is low, and the heating tension of only the sheath yarn fiber is 0.06 to 0. .1g/d
In this range, the core yarn and sheath yarn have high entangling properties, and a good coated elastic yarn can be obtained.

In the method for producing covered elastic yarn, the thermoplastic multifilament supply system serving as the sheath yarn is subjected to false twisting and crimping, and false twisting is performed in the composite plate twisting process with the elastic yarn. direction,
By setting the sheath yarn in the opposite direction to the false twisting direction of the crimped yarn to be supplied, the opening property (increase in torque) of the sheath yarn immediately after the yarn feeding roller in the composite plate twisting process is improved, and the core/elastic yarn is bonded with the elastic yarn. A major feature is that the sheath structure can be easily formed. Conventional composite plate twisting involves controlling the feeding tension of the sheath yarn to a low level, using special guides before and after the yarn feeding roller to form a core/sheath arrangement, and fusing the single fibers of the sheath yarn. In order to achieve this, it was necessary to increase the entanglement of the core yarn and sheath yarn by processing the sheath yarn at a temperature higher than the melting start temperature of the sheath yarn. These problems are caused by the lack of stability in the quality of the core in the spindle in industrial production, the variation in dyeability near the temperature at which the sheath yarn begins to fuse, and the quality of the elastic yarn that is the core yarn. In order to prevent the covered elastic yarn from elongating due to thermal deterioration and to improve entangling properties, it is necessary to use fibers with a low melting start temperature as the sheath yarn fibers. In contrast to such prior art, in the present invention, the core/sheath arrangement of the elastic yarn and sheath yarn is made easy to intertwine, which increases the entanglement of the core yarn and elastic yarn, so that it is possible to fuse the sheath yarn fibers. In addition, it has become possible to easily produce the sheath fiber without using low tension yarn feeding or special guides. False twisting the sheath yarn supplied to the composite plate twisting process ′p/
! By processing the fiber in the opposite direction to the false twisting direction of the sheath yarn that supplies the false twisting direction in the composite plate twisting process, the torque of the single filament of the sheath yarn fiber of the obtained covered elastic yarn becomes small. When the coated elastic yarn is relaxed under no load at 90°C for 20 minutes and then relaxed by 50% from the tensioned state, the length of the snarl filament loop formed by the single filament of the sheath yarn is 1 inch. It becomes less than l. As a result, the knitted fabric obtained using the yarn of the present invention has a very beautiful knitted fabric with a flat appearance and no Snarl filament loops protruding onto the knitted surface.

Furthermore, the yarn according to the present invention has a smaller torque than the conventional yarn, and the diagonal of the knitted fabric is small even when used on jersey fabrics.

Note that the draft rate of the elastic yarn is appropriately selected depending on the desired elongation rate of the covered elastic yarn, and is usually set in the range of 2.0 to 4.0 times.

The tension of the sheath yarn fibers supplied to the composite plate twisting can be within the range of 0.03 to 0.1 g/d, which is the same as in normal false twisting, but the sheath yarn fibers cannot be crimped. In order to supply it in an elongated manner, around 0.1 g/d is preferable.

Next, a covered elastic yarn and a method for manufacturing the same according to the present invention will be explained with reference to the drawings.

FIG. 1 shows an example of a false twisting device used to carry out the method for producing covered elastic yarn of the present invention.

The polyurethane elastic yarn package 2 is rotated in the direction of the arrow by the positive yarn feeding roller 3 and stretched to a certain extent between the yarn feeding roller 4 and the active yarn feeding roller 3 . The polyurethane elastic fibers that have come out of the positive yarn feeding roller 3 are fed in the form of a sheath yarn crimped yarn 1 and a yarn feeding roller 4 in the form of aligned gold threads, which are mostly released in a tension-free state. This composite yarn is heated with a false twisting spinner 6, heat treated with a false twisting heater 5, and thermally fixed after heating.

It is cooled between the false-twisting heater 5 and the false-twisting spinner 6, untwisted by the false-twisting spinner 6, passes from the delivery roller 7 through the guides 8 and 9, and is wound up into a rolled cheese by the winding roller 10 to make the coated elastic material. A thread 20 is obtained.

FIGS. 2 and 3 are model diagrams when the covered elastic yarn is relaxed by 50%. As shown in FIGS. 2(A) and 3, the coated elastic yarn obtained according to the present invention is good because even when loosened, the filaments 11 of the sheath yarn around the elastic yarn 2 do not form snarl filament loops. However, as shown in Fig. 2 (B), the conventional product shows a covering property of
The filaments 11 of the sheath yarn around form a snarl filament loop 12 and cover it.

FIG. 4 is a cross-sectional view of the covered elastic yarn 20 of the present invention, where the large cross-sectional shape at the center is the elastic yarn 2, and the many small ones around it are the single fibers 11 of the sheath yarn.

〔Example〕

Examples of the coated elastic yarn with low swirling properties according to the present invention will be shown below, and a comparison will be made in terms of physical properties with comparative examples.

Before explaining the examples, each measurement method used to evaluate the physical properties of the coated elastic yarn with low swirling property will be explained.

◎ Degree of entanglement A load of 1 g/d is suspended for 1 minute on the coated elastic yarn according to the present invention, a mark is made between 50 CO1, the load is removed, and after leaving it for 30 seconds, a load of 1 g/d is suspended for 1 minute again. After that, the load was removed and the load was left for 30 seconds, and then a load of 1 g/d was applied again, and the elastic thread and sheath thread were separated with a thin bottle to the upper mark of the 50 cm mark, and 0.1 g/d was applied to the branch point. suspending the load of
The length that this load pulled both threads! ! , and the degree of entanglement is expressed by the following formula: ◎ After the torque processing, the yarn was left in an atmosphere at a greenhouse temperature of 20°C x 65% for one week, and the coated elastic yarn 20 of the present invention was attached to the thin pin 21 in this atmosphere. As shown in FIG. 5A, a load W of 0.1 g/d is hung on this, and then a load W of 0.025 g/d is placed 1 m from the pin 21 as shown in FIG. 5B.
Add a load W2 of d and remove the previous load W1 of 0.1 g/d, and apply a load W2 of 0.025 g/d.
As shown in FIG. 5C, the yarn is allowed to rotate freely in a suspended state, and when the rotation stops and stabilizes, the number of twists in the yarn is read and used as torque. The unit is T/2 m
shall be.

◎ Length of the Snarl Filament Loop After the coated elastic yarn of the present invention is made into a general shape and subjected to heat relaxation treatment under dry heat at 90°C and no load for 20 minutes, as shown in FIG. 6A, the elastic yarn 20 is Grip one end with the clip 23 and attach 0.1 to the other end.
Hang a load W of g / d, and mark the distance between 1 m as 22a.
, 22b, excluding the load W, mark 22a, 22b
When the length of the loop 12 is 50 m, the length l of the loop 12 formed by the Snarl filament protruding around the covered elastic yarn 20 is measured, as shown in FIG. 6B.

◎ Elongation recovery rate The coated elastic yarn of the present invention was subjected to heat relaxation treatment under dry heat at 90°C for 20 minutes under no load, and then the yarn was placed in a Tensilon type tensile tester at an initial load of 100cm. 100%
A constant elongation cycle is given, and the elongation recovery rate at the 10th repetition is determined.

In this example, changes in the characteristics of the covered elastic yarn of the present invention are understood by changing various manufacturing conditions of the covered elastic yarn. That is, polyurethane elastic yarn (T-t=23
0℃) 20d/4f as the core thread, nylon 66 multifilament ('r,,=255℃) 40d/34f
Using a false twisted crimped yarn consisting of the following as a sheath yarn, coated elastic yarns were manufactured using a false twisting machine with a heater length of 1 m at a processing speed of Loom/min under various manufacturing conditions. Table 1 shows the manufacturing conditions that were changed and the properties of the coated elastic yarns obtained.

The changes in manufacturing conditions in this example can be broadly classified into the following six types.

1st group -- 1 --- When a yarn that has not been false twisted is used for the sheath yarn, 2nd group --- -- When the direction of false twisting of the primary and secondary (composite) is the same, 3rd group --- If the number of false twists during secondary (composite) false twisting is changed, 4th group --- -- If the false twisting temperature during plate twisting is changed, 5th group --- ---When the number of primary false twists is changed, 6th group ---When the false-twisting temperature during secondary (composite) false-twisting is changed, each group will be explained below.

◎ As shown in Comparative Examples A and B in Group 1 Table 1, when a yarn that has not been false twisted is used as the sheath yarn, the properties of the covered elastic yarn are inferior in all items.

■ As shown in Comparative Example C in Group 2 Table 1, even if false twisted crimped yarn is used as the supply system, the false twisting direction in the composite plate twisting process is the same as the false twisting direction of the sheath yarn crimped yarn. When the sheath yarn is in the direction of The covering properties, that is, the entangling properties of the obtained covered elastic yarn were low.

◎ 3rd group In this group, the composite plate twist number T2 is Z 2800 T
/M (=0.66TI), Z2960T/M (
=0.70T, ), 23800T/M (=0.90
T, ) and Z 5200 T/M (=1.24
The test was conducted by changing to TI). Inventive products 1 and 2 shown in Table 1 use false twisted crimped yarn as the sheath yarn fibers to be supplied to the composite plate twisting process, and the false twisting direction in the composite plate twisting process is the same as the false twisting direction of the sheath yarn. By processing in the opposite direction and setting the number of false twists in the composite plate twisting process to 170°C or higher, where the adhesiveness of the elastic yarn is exhibited, and meeting the conditions of the present invention, the special guide that was performed in the prior art can be removed. By using this method and controlling the supply tension to a low level, it was possible to obtain a coated elastic yarn with excellent covering properties.

0 for the number of twists T in one plate of the supplied false twisted yarn. Below TXTI, the entanglement of the obtained covered elastic yarn is low as in the comparison example, and the core yarn and elastic yarn are likely to separate due to the action of external force (repeated stretching, frictional resistance with guides, etc.). This is thought to be because the migration of the sheath filaments in the false twisting region is small, and the random twisting of the sheath filaments with respect to the core yarn is reduced.On the other hand, as in Comparative Example E, <1.2X
Covered elastic yarns obtained at TI or higher are susceptible to so-called core yarn breakage, in which the elastic yarns are cut. This is thought to be because the migration in the heating region becomes large and the elastic yarn is also pushed out to the outside of the heating yarn, and the elastic yarn that comes out to the outside of the heating yarn comes into contact with the heating heater and is cut. In addition, when it is 1.2XT1 or more, the opening property of the sheath yarn filament immediately after the yarn feeding roller becomes low, and the covering property of the obtained covered elastic yarn also becomes poor.

■ As shown in Comparative Example F in Table 1 of the 4th group, when the temperature of the primary false-twisting heater is below the melting point (T-+) of thermoplastic fibers (70°C), the torque force immediately after the false-twisting yarn feeding roller is small; On the other hand, as shown in Comparative Example G, at T-+ 20°C or higher, inter-filament fusion occurs, the fibrillation property of the composite plate twisting immediately after the yarn feeding roller is small, and the entangling property of the resulting covered elastic yarn is poor. becomes worse.

◎ 5th Group In this group, tests were conducted with various changes in the number of primary false twists, T. In this example, 40 d/34 f nylon 6
Since 6 is used, 2960T/M (=4229X O,7) ~ 4652
T/M (=4229X 1.1 ) is within the scope of the present invention (Inventive product 3 and Inventive product 4). - When the plate twist number is 2960 T/M or less, the entangling properties of the obtained covered elastic yarn deteriorate as shown in Comparative Example H. On the other hand, if the number of primary false twists is 4650 T/M or more, as shown in Comparative Example 1, the entangling properties of the obtained covered elastic yarn deteriorate. The reason for this is that if the number of false twists is too low, the torque force immediately after the yarn feeding roller during the composite board twisting process is large, but the opening properties are poor due to coarse crimp, and the number of false twists is too high. The torque force immediately after the yarn feeding roller is small, and the fiber opening performance is poor due to the fine crimp.

■ 6th Group In this group, tests were conducted by varying the temperature t2 of the twisted composite plates. That is, as shown in Comparative Example J in Table 1,
If the false twist number is below 170°C, the adhesion between the polyurethane elastic yarn of the core yarn and the thermoplastic fiber multifilament yarn of the sheath yarn is insufficient, and the core/sheath structure formed immediately after the yarn feeding roller is untwisted. It cannot be maintained until later, the intertwining of the core yarn and sheath yarn becomes poor, and the temperature of the heater during composite board twisting is 17.
A temperature of 0°C or higher is required. On the other hand, when the false-twisting temperature in the comparative example exceeds the melting point (T-z) of the polyurethane elastic yarn (T-z) -10°C, the elastic yarn deteriorates significantly (the elongation recovery of the obtained yarn is poor, and the elastic yarn is coated). Since some parts of the yarn may break inside the yarn or a so-called core yarn phenomenon may occur, the number of false twists in the composite plate twisting process, such as products 5 and 6 of the present invention, is 170°C or higher, and T m t-1.
The preferred range is 0''C or less.

Below is the remaining O Heaven I Tsumu Sheath yarn is 40 denier of nylon 66 (melting point 255℃), 34 filament yarn is false twisted in the S direction, and the number of false twists is 42
00T/M, a crimped yarn that has been false-twisted at a false twisting temperature of 210°C is used, and a 20-denier 3 filament of polyurethane yarn (melting point 230°C) is used as the elastic yarn as the core yarn, and the draft rate of the elastic yarn is 0.1g/d while stretching at 3.0 times
The sheath yarn was pulled together with the crimped yarn with a yarn feeding tension of M
Processing was carried out at a false twisting temperature of 200° C., a false twisting feed rate of ±0%, and a winding feed rate of +5%.

The degree of entanglement of the obtained covered elastic yarn was 90%, the torque was 737/2 M in the Z direction, the length of the snarl filament after thermal relaxation of the covered elastic yarn was 0.7 m, and the elongation recovery rate was 9.
0%, and there was no core yarn breakage of the elastic yarn (good results).

In addition, when a tights fabric was knitted using this coated elastic yarn, the appearance of the fabric was flat with no protruding loops due to snarl loops, a soft texture was obtained, and the fabric was of good quality with no oblique direction. Quality tights products, now available.

Example 3 A 20 denier 7 filament yarn of nylon 66 was used as M yarn, the false twist direction was the S direction, the number of false twists was 6000 T/M, the crimped yarn was subjected to friction false twisting at a false twist temperature of 210°C, and the core was The elastic yarn is a polyurethane elastic yarn of 20 denier 4 filaments, and while the elastic yarn is stretched at a draft rate of 3.0 times, it is aligned with the sheath yarn crimped yarn with a yarn feeding tension of 0.15 g/d. The yarn was then guided to a false twist feed roller and subjected to a composite plate twisting process. The speed of twisting composite plate is 80m/min.
The false twisting direction is the Z direction, the number of false twists is 4200 T/M,
Processing was carried out at a false twisting temperature of 210° C., a false twisting feed rate ±0%, and a winding feed rate +5%.

The degree of entanglement of the obtained covered elastic yarn was 95%, the torque was 100T/2M in the Z direction, the length of the snarl filament after thermal relaxation of the covered elastic yarn was 0.4 Tsuru, and the elongation recovery rate was 85.
% coated elastic yarn with no breakage of the core yarn. When this yarn was used to knit pantyhose, a product with good knitting properties, a comfortable fit, and a beautiful appearance was obtained.

The sheath thread is 70 denier nylon 6 (melting point 220℃).
4 filament yarn, false twist direction is S direction, number of false twists is 340
0T/M, a crimped yarn that has been false-twisted at a false-twisting temperature of 180°C is used, and the elastic yarn that is the core yarn is polyurethane elastic yarn 4.
Using a 0 denier 5 filament, the elastic yarn was drawn at a draft rate of 3.3 times and aligned with the sheath yarn crimped yarn with a yarn feeding tension of 0.1 g/d, and guided to a false twist yarn feeding roller to form a composite plate. Twisted. Increased speed of composite board twisting to 10
0 m/min, false twist direction is Z direction, number of false twists is 3000 T
/M, false twisting temperature 175℃, false twisting feed rate +0%
, the winding feed rate was +5%. The processing tension was 5 g for the false twisting cuff, and 17 g for the untwisting tension.

The degree of entanglement of the obtained covered elastic yarn was 85%, the torque was 307/2 M in the Z direction, the length of the snarl filament after heating the covered elastic yarn was 0.5 m, and the elongation recovery rate was 95%.
A good coated elastic yarn was obtained without any breakage of the core yarn of the elastic yarn.

When we created a cross-knit circular knitted fabric using the coated elastic yarn and 60 count cotton yarn, there were no troubles during the knitting process, and the dyed finished fabric had no protruding loops due to snarl lube, and the stitches were beautiful and flat. A knitted fabric with a soft texture was obtained.

〔Effect of the invention〕

Since the low-turning coated elastic yarn according to the present invention is configured as described above, it has excellent covering properties, no deterioration of the elastic yarn, excellent elongation recovery properties, and low turning torque. As a result, the knitted fabric made using the covered elastic yarn according to the present invention does not slant even on jersey fabric, has a flat appearance, and has excellent bulk. Furthermore, if the production method according to the present invention is used, the coated elastic yarn with low swirling property according to the present invention can be obtained simply by using a conventionally known false twisting machine and appropriately selecting the processing conditions.
A coated elastic yarn having the aforementioned excellent performance can be stably and economically produced.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing an example of a false twisting machine used to carry out the manufacturing method according to the present invention, and FIG. 2 shows a coated elastic yarn according to the present invention (FIG. 2A) and a conventional coated elastic yarn. (Fig. 2B) is a model diagram showing the appearance in a 50% relaxed state, and Fig. 3 shows the coated elastic yarn according to the present invention in
FIG. 4 is an enlarged front view showing the yarn in a 0% relaxed state; FIG. 4 is a cross-sectional view of the yarn shown in FIG. 3; FIG. FIG. 6 is an explanatory diagram illustrating a method for measuring the length of a Snarl filament loop of a covered elastic yarn. 1... Sheath yarn crimped yarn, 2... Polyurethane elastic yarn, 5... False twist heater, 6... False twist spinner,
11...Single filament of sheath yarn crimped yarn, 12...
Snarl filament lube, 20... coated elastic thread. Figure 11 No. 4 20 Figure 5

Claims (1)

[Scope of Claims] 1. A coated elastic yarn whose core yarn is polyurethane elastic fiber and whose sheath yarn is a low-turning false twisted crimped yarn made of thermoplastic fiber multifilament yarn, comprising (1) The core yarn is located almost at the center of the covered elastic yarn, and the sheath fibers twist and cover the core yarn so as to uniformly wrap the outer periphery of the core yarn. Each single fiber of the twisted crimped yarn intermittently and randomly reverses its twisting direction in the length direction and intertwines with the core yarn, and the single filaments of the core yarn and sheath yarn partially adhere and converge. (3) each single filament constituting the core yarn and sheath yarn is arranged in the yarn axis direction in a substantially untwisted state; 4) When the composite yarn is relaxed by 50% from the tensioned state after dry heat relaxation treatment at 90°C for 10 minutes, the length of the snarl filament loop formed by the single fibers of the multifilament of the sheath yarn is 1 mm or less. A coated elastic yarn with low swirling properties. 2. In a composite false-twisting method in which stretched polyurethane elastic fibers and thermoplastic false-twisted crimped multifilament yarn are fed into the same false-twisting device, the false-twisted crimped multifilament yarn of the feeding system is set in the direction of false-twisting heating. A method for producing a coated elastic yarn with low swirlability, characterized by successively performing heating, heat setting, and untwisting under the following conditions in the direction opposite to the heating direction of false twisting of the yarn: (1) {0.7 [(23000 /√D)+590〕≦T
_1≦1.1 [(23000/√D)+590]}(2
)0.7T_1≦T_2≦1.2T_1(3)T_m_
1-70℃≦t_1≦T_m_1-20℃ (4) 170
°C≦t_2≦T_m_2−10°CT_1; Number of false twists (number of primary false twists) of false twisted crimped yarn to be supplied, T_2; Number of false twists during composite false twist (number of secondary false twists), t_1:
false-twisting heater temperature (primary false-twisting heater temperature) of the supplied false-twisted crimped yarn, t_2; false-twisting heater temperature during composite false-twisting (secondary false-twisting heater temperature), T_m_1; melting point of thermoplastic multifilament yarn; T
_m_2: melting point of polyurethane elastic fiber, D: denier of thermoplastic multifilament.