JPH043455B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to a method for producing a covered elastic yarn by covering an elastic yarn with a filament yarn. [Prior Art] Conventionally, coated elastic yarns made by mixing and interlacing elastic yarns such as urethane and filament yarns (especially false twisted crimped yarns) have been disclosed in Japanese Patent Publications No. 40-21496, No. 44-6140, It is known from Publication No. 42-21303. However, when producing such a covered elastic yarn, an elastic yarn drafted (stretched) by several hundred percent and a filament yarn that has been overfed in contrast to the elastic yarn are introduced into a turbulent flow nozzle. Because this method was adopted, there were the following drawbacks. a The elastic yarn and filament yarn have poor mixing and entangling properties, and the number of entanglements does not particularly increase. b Even if the apparent number of confounds increases, the confounding strength of each confounding part is weak. c From the above points a and b, the covering elastic yarn does not have sufficient cohesiveness, and therefore has poor unwinding properties during knitting, and neps caused by filaments occur frequently. d As a result, fatal defects such as poor grain appearance occur in products such as knitted fabrics. Furthermore, in Japanese Patent Publication No. 56-25535, an elastic yarn that is untwisted and stretched to 100% in one step while being fed out from a package cage is supplied to the yarn during false twisting and crimp processing, and both yarns are combined and then relaxed. A method has also been proposed in which it is introduced into an entangling nozzle in a state in which it is present. As shown in Figure 2 of the same publication, the coated elastic yarn obtained by this method is not so entangled that when relaxed, the elastic yarn contracts in a substantially straight line independently of the false-twisted crimped yarn. The coating elasticity shown in the above-mentioned publication is not exclusive to this example. In addition, when using this method, the elastic yarn and the false-twisted crimped yarn are brought into a relaxed state after being combined, so that the surplus yarn of the false-twisted crimped yarn intermittently occurs due to the contraction of the elastic yarn. In the process, quality problems such as thread clogging in the nozzle, formation of neps, and variation in entanglement density due to tension fluctuations are unavoidable. Moreover, in this case, the elastic yarn is directly stretched to 100% and taken out from the bag cage by friction drive, so the pulling force increases and the unraveled yarn scrapes the surface of the bag cage, resulting in smooth unwinding. (drawing out) is not performed and the yarn is easily broken. For the reasons described above, a coated elastic yarn that exhibits a well-balanced and strong intertwined structure with good process passability has not yet been realized. [Objective of the Invention] The object of the present invention is to eliminate the drawbacks of the above-mentioned conventional methods, to provide a uniform appearance without unevenness such as neps, and to improve the number of interlaces and interlace strength, thereby eliminating any hindrances during knitting. It is an object of the present invention to provide a method for producing a coated elastic yarn that does not cause problems and gives a well-balanced product. [Structure of the Invention] In realizing a well-balanced and stable covered elastic yarn, the present inventors have discovered that the method of drafting the elastic yarn, the peculiar tension reduction behavior in the elongation recovery curve of the elastic yarn, and the false twist crimp yarn. The present invention was achieved by discovering that factors such as the manner in which the liquid is supplied to the fluid entangling nozzle are intertwined in a complex manner. Thus, according to the present invention, when producing the covered elastic yarn, the elastic yarn is
A draft zone that obtains a predetermined draft rate of 100% or more is provided following the preliminary draft zone extending to
The elastic yarn that has been drafted to a predetermined draft rate in the two-stage draft zone is then reduced to a draft rate of 5% to 30%.
% reduction to create an apparent overfeed state, the yarn is introduced into an interlacing treatment nozzle, and the false twisted crimped yarn is supplied to the interlacing nozzle independently from the elastic yarn to mix and entangle both yarns. A method of manufacturing a coated elastic yarn is provided. Hereinafter, the present invention will be described above with reference to the accompanying drawings. 1st
The figure is a side view of the coated elastic yarn according to the present invention when placed under no tension, in which 1 is the twisted inflection point, 2 is the flowering part formed by the constituent filaments of the false twisted crimped yarn, and 3
4 is an elastic yarn, and 4 is a false twisted crimped yarn. Here, the twist inflection point 1 corresponds to the intertwining part of the elastic yarn 3 and the false twisted crimped yarn 4, and in the present invention, since the intertwining strength of both yarns is significantly improved, both yarns are integrally formed. In particular, it forms an inflection point where it can be twisted by more than 90 degrees. On the other hand, when the conventional covered elastic yarn is placed under no tension, the situation is as shown in FIG. 2, and the characteristic feature is that the elastic yarn is compressed approximately in a straight line. In other words, when the conventional coated elastic yarn, like the one of the present invention, is placed under no tension, the elastic yarn does not meander or behave together with the filament yarn. It was not obtained. In addition, FIGS. 3 and 4 show that the coated elastic yarn of FIG. 1 (present invention) and FIG. 2 (conventional example) is
In the side view when a tension of g/1 de is applied, there is apparently no essential difference between the two, but the intertwined part 5 of the present invention is slightly longer, and this The essential difference from FIG. 4 is that the interlacing strength of the interlacing portion is extremely strong, so it has potentially strong interlacing characteristics that cause torsional inflection points. In the present invention, the elastic thread typically refers to a polyurethane thread (usually having a monofilament denier of 20 de to 140 de), and usually one thread is used. On the other hand, any type of kimono or false-twisted crimped yarn may be used, but those made of ordinary polyester, polyamide, etc. can be used. This type of false twisted crimped yarn has a thickness (de) of
It has a total denier of 0.4 to 7 times and the number of filaments. One composed of 3 to 68 pieces is preferably employed. In view of the texture of the knitted fabric, the coverage of the elastic yarn, etc., the false twisted crimped yarn preferably has a visible shrinkage ratio (VC) of 10% or more. Here, VC follows the following definition. It represents the amount of crimp that occurs at room temperature, and is expressed by the following formula. VC={(l ₀ −l ₁ )/l ₀ }×100 (%) l ₀ : Length of the skein after applying an initial load of 2 mg/de and a heavy load of 0.1 g/de and leaving it for 1 minute. l ₁ : From l ₀ above, 1 after removing the heavy load of 0.1 g/de
The length of the skein after minutes. Further, for such a covered elastic yarn, it is appropriate that the number of entangled portions is 50 to 250 per meter and the length thereof is 0.5 to 15 mm. If the number of intertwined portions is less than 50/m or 0.5 mm, the cohesiveness of the covered elastic yarn is insufficient, resulting in poor unraveling during knitting or weaving of neps. Also, if the number of entangled parts exceeds 250 pieces/m or 15 mm,
Because the convergence is too strong, it tends to affect the stretchability (especially when the initial elastic modulus is high) when it is made into a product. Next, a method for manufacturing the coated elastic yarn of the present invention will be described. FIG. 5 is a schematic diagram of a manufacturing apparatus suitable for obtaining the coated elastic yarn of the present invention, in which the elastic yarn 3 is transported between a friction (supply) roller 8 and a first draft roller 9, which frictionally drive the package. ~70% (preliminary draft with draft rate _D1 ), and then drafted to a predetermined draft rate ( _D2 ) in the draft zone formed by the roller 9 and the second draft roller 10 (second stage draft) ),
Subsequently, the fibers are supplied to a mixing/entangling treatment zone formed by the second draft roller 10, the relaxation/third draft roller 14 which rotates at a lower speed (peripheral speed) than the draft roller, and the turbulence nozzle 11 (the draft in this zone rate D ₃ is less than D ₂ ). The above-mentioned predetermined draft ratio D ₂ corresponds to the final stretching ratio in two-stage drawing of the filament, and the draft ratio (stretching ratio) of the preliminary draft zone is d ₁ (times), and the draft ratio of the draft zone is d 1 (times). When the magnification (stretching ratio) is d ₂ (times), d ₁
×d ₂ =D ₂ /100 (D ₁ and D ₂ are expressed as %). Predetermined draft rate (D ₂ ) in the above draft zone
The elongated elastic modulus is 5% or more lower than the “predetermined draft rate D ₂ ” in the mixed fiber/interlacing zone [(D ₂ −5)
≧D ₃ ]. In other words, if the draft rate in the draft zone is 200%, it is preferable to maintain the draft rate in the mixed fiber/entanglement zone at 5 to 30% lower than the above draft rate (195 to 170%). In this mixed/entangled zone, the elastic yarn is in a draft state of 195 to 170% (draft rate D ₃ ), but from the draft rate of 200% in the draft zone in advance, the above D ₃ is relatively ( (Apparently)
This means that the body has been relaxed by 5-30%. The effect in this respect will be explained in detail in the "effect" section below. Here, the prescribed draft rate of elastic yarn is usually
The draft rate is 150% to 300%, and on the other hand, it is preferable to set the draft rate to be 5% to 15% lower than the above draft rate in the mixed/entangled zone. Returning to FIG. 5 again, the false twisted crimped yarn 2 fed out from the supply roller 12 is simultaneously introduced into the turbulent flow nozzle 11, and both yarns are mixed and entangled in the nozzle and become relaxed and a third draft. It is taken up by the roller 14 and reaches the winder 13. The feature of this supply mode is that by providing a supply path for the false twisted and crimped yarn to the interlacing nozzle 11 separately from the drafting process of the elastic yarn, both yarns are supplied independently (immediately before the interlacing nozzle 11). This is the first time that both threads are in a doubling state. This prevents sagging of the false-twisted crimped yarn and fluctuations in tension within and between the yarns, which occur in the conventional method in which the yarn is initially plied. Furthermore, this independent supply system makes it possible to ensure the optimum tension for obtaining a good entangling effect (the optimum tension is completely different for elastic yarns and false twisted crimped yarns). Regarding the supply rate of this false twisted yarn, the relaxation and third draft roller 14
It is preferable to overfeed by 2% to 10%. Here, the overfeed rate (OF) is determined by the following formula. OF={(V ₁ − V ₂ )/V ₂ }×100% V ₁ ... Circumferential speed of the supply roller 12 V ₂ ... Circumferential speed of the relaxation and third draft roller 14 In addition, as a turbulent flow nozzle, in this world Commonly used interlace nozzles, taslan nozzles, etc.
Anything can be used. [Action of the invention] The coated elastic yarn obtained by the method of the invention is
There is virtually no thickness unevenness (neps due to excess yarn) along the longitudinal direction, and the elastic yarn and false twisted crimped yarn have an unprecedented tightly intertwined structure, even when the covered elastic yarn is relaxed. Both yarns behave as one, exhibiting an intertwined structure that exhibits twisting and inflection points. This structure is completely different from the conventional method. Specifically, (a) the elastic yarn is drafted in two stages, and the first stage has a draft of at most 70%.
% draft rate to stabilize the unwinding tension and the unwinding process. (b) The elastic yarn stretched to a predetermined draft ratio (D ₂ ) is relaxed by 5% to 30% in the entangling treatment zone to obtain the optimal tension for interlacing. For example 20de
For the polyurethane yarn, the preferred tension is around 2 g (1.0 to 3.0 g) in order to obtain a good entangling effect while maintaining stretch power. Figures 6 and 7 show the elongation recovery curves when the elastic yarn (20 de polyurethane yarn) was stretched to 200%, 238%, and 260%, respectively, and then gradually relaxed. can be seen. From Figure 6, the thread tension (stress) at 200% elongation is 4.8g, but if this is relaxed by only 5% (D ₃ =
225%), and the thread tension is extremely reduced to 3g. From Figure 7, the thread tension at 230% elongation is 8.6g, but when this is only relaxed by 15% (D ₃ = 215%)
The thread tension is extremely reduced to 3g. From Figure 8, the thread tension at 260% elongation is 6.7g, but this decreases to 2.9g with just 10% relaxation (D ₃ = 250%), and the ratio of stress reduction to relaxation rate can be compared. It's so huge that it's impossible. (c) However, the present invention cannot be realized only with the requirements (a) and (b) above, and it is further necessary to supply the false twisted crimped yarn separately from the elastic yarn. This is because the optimum entanglement tension of the crimped yarn is approximately 0.2 g, which is significantly lower than that of elastic yarn. Based on the above, the present invention can stably unwind elastic yarn while reducing the draft rate by 5% to 5% from the predetermined draft rate of the two-stage draft.
The elastic yarn in a 30% relaxed state, that is, the elastic yarn in a negative stress gradient, is intertwined with the false twisted crimped yarn while maintaining each under the optimal intertwining tension, so both yarns behave as one. By doing this, it is possible to obtain a coated elastic yarn which not only has entangled portions that are strong enough to cause twisting inflection points, but also has a uniform appearance. In this regard, when supplying the elastic yarn and the false twisted crimped yarn to the interlacing nozzle in a pre-combined state, there is an imbalance in the supply tension difference between the two yarns, and it is difficult to obtain the optimum interlacing tension for each yarn. The covering structure is undesirable. [Effects of the Invention] According to the present invention, the following excellent effects can be achieved. a. The blending and entangling properties of the elastic yarn and filament yarn are extremely good, and the number of entanglements increases in particular. b Not only is the number of interlaces increased, but the interlace strength of each interlace part is strong. c From the above points a and b, the covering elastic yarn has sufficient cohesiveness and therefore has good unwinding properties during knitting, and there is no concern that neps will occur frequently due to filaments. d As a result, a beautiful surface can be obtained in products such as knitted fabrics. e Appropriate stretchability can be achieved because the convergence can be controlled appropriately. [Examples and Comparative Examples] Using the process shown in FIG. 5, coated elastic yarns were obtained under the following yarn usage and processing conditions. A Thread usage ●Elastic thread 3...Polyurethane 20de 1 piece used ●Filament thread 4...Nylon 61-stage heater false twist crimped yarn Table below Experiment No. 1-2 40de/34fil 3-4 13de/5fil 5-6 20de/ 16fil 7-8 70de/24fil B Processing conditions and results As shown in the table below.

[Table] The coated elastic yarn of the present invention can be used at 600 r.pm on a pantyhose knitting machine.
It could be assembled without any problems even at high speeds. On the other hand, the comparative example has the above 600r.pm.
Under this, the crimped yarn was knitted in a knot shape at the start, and during running, there were frequent holes in the knitted fabric due to yarn breakage and abnormal tension.

[Brief explanation of drawings]

1 and 3 are side views showing covered elastic yarn obtained by the method of the present invention under no tension and under tension, respectively, and FIGS. 2 and 4 are coated elastic yarns obtained by the conventional method. A side view showing the state of the elastic yarn under no tension and under tension, respectively. Figure 5 is a schematic diagram showing an example of the manufacturing process of the covered elastic yarn according to the present invention. Figures 6 to 8 are the elastic yarn. It is a graph which shows the elongation recovery curve of. 1... Twisted inflection point, 2... Blossoming part of filament thread, 3... Elastic thread, 4... Filament thread,
8... Elastic yarn supply roller, 9... Elastic yarn first draft roller, 10... Elastic yarn second draft roller, 11... Entanglement nozzle, 12... Filament yarn supply roller, 14... Elastic Thread relaxation and third draft roller.

Claims (1)

[Claims] 1. When producing the covered elastic yarn, the elastic yarn is 5% to 70%
Preliminary draft zone continues to stretch to 100%
A draft zone that obtains a predetermined draft rate of % or more,
After that, an entanglement treatment zone equipped with an entanglement nozzle is provided, and the elastic yarn that has been drafted to a predetermined draft rate in the two-stage draft zone is reduced to 5%.
Introducing the yarn into an interlacing treatment nozzle while reducing the elastic yarn by ~30% to create an apparent overfeed state, and supplying the false twisted crimped yarn to the interlacing nozzle independently from the elastic yarn to mix and entangle both yarns. A method for producing a covered elastic yarn characterized by: 2. The method for producing a covered elastic yarn according to claim 1, wherein the draft rate is 200% or more. 3. The method for producing a covered elastic yarn according to claim 1, wherein the elastic yarn is a polyurethane yarn. 4. The method for producing a covered elastic yarn according to claim 1, wherein the false twisted crimped yarn is a polyester filament yarn. 5. The method for producing a covered elastic yarn according to claim 1, wherein the false twisted crimped yarn is a nylon filament yarn. 6. The method for producing a covered elastic yarn according to claim 1, wherein the false twisted crimped yarn has an apparent crimp rate of 10% or more.