JPS62162038A - Polyamide 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 covered elastic yarn and a method for manufacturing the same.

More specifically, the polyurethane elastic yarn is coated with polyamide multifilament yarn, which has an extremely fine single fiber fineness and a high multifilament count compared to the covering yarn used in conventional similar covered elastic yarns. substantially untwisted false-twisted coated elastic yarn and its ￥A
It is related to the manufacturing method.

The coated elastic yarn according to the present invention can be used for leg accessories such as socks, tights, pantyhose, and body parts that can fully utilize surface effects such as softness when directly touching the skin due to its yarn characteristics and yarn structure. It can be optimally used as a foundation for suits and the like.

(Prior art) Conventionally, one of the methods for manufacturing covered elastic yarn is to arrange elastic yarn and polyamide multifilament yarn so that they form a core/sheath shape, and then twist them into composite plates to temporarily transform them into elastic yarn. A technique is known in which a twisted crimped yarn is twisted and reversed to obtain a yarn structure in which the yarn is covered with substantially no twist.

However, this technique has the following drawbacks.

In other words, if a multifilament yarn with a thin single fiber denier and a large number of filaments is used as a sheath yarn, when it is combined with a core yarn to complete the false twisting process, it will In this case, it becomes difficult for the thread that is to become the core to be inserted into the sheath thread, and the core/glass arrangement structure cannot be properly formed, resulting in the inability to form a coated elastic thread.

In other words, since the core yarn and the sheath layer yarn are subjected to the false twisting process while being separated, the result is a false twisted yarn in which both yarns are simply aligned.

In addition, as mentioned above, when the single fiber filament denier becomes thinner and the number of filaments increases, the method of inserting 12 to 18 actual twists per meter of yarn, which has been conventionally used as a method of bundling the constituent fibers in multifilament yarn, becomes fluffy. Recently, methods using air entanglement processing have been widely used as a method to provide convergence, and at the same time rationalization by increasing speed has also been carried out. There is. When such an air entanglement treatment system is used as a sheath yarn, the above-mentioned core/glass arrangement structure becomes even less likely to occur.

[Problem that the invention seeks to solve]

For the reasons mentioned above, it has been difficult to manufacture false-twisted covered elastic yarns using multifilament yarns with a thin single fiber denier and a large number of filaments as sheath yarns. Currently, the denier of single fiber filaments is at most as small as 2 denier.

However, in recent years, with the boom in natural fibers, there has been a strong desire in the industry to develop products using coated elastic yarns that have the characteristics of cotton, such as the soft texture, mild luster, transparency, and soft fit. I came.

In view of the above points, an object of the present invention is to improve the drawbacks of the prior art as described above, and to make it possible to obtain a knitted fabric that has a cotton-like appearance and feel and has excellent covering properties. The purpose of the present invention is to provide a false-twisted coated elastic yarn and a more rational manufacturing method.

[Means for solving problems]

The present invention, which achieves the above-mentioned objects, has the following configuration.

That is, the coated elastic yarn of the present invention has a substantially non-twisted structure in which a polyurethane elastic yarn is located in the core portion and a polyamide multifilament yarn is placed in the sheath portion to cover the core portion. In the twisted coated elastic yarn, the polyamide multifilament yarn has a single filament denier of 1.5 d or less, a number of filaments of 40 or more, and a boiling water shrinkage rate of 6% or less, and the stretch rate of the coated elastic yarn is The polyamide-coated elastic yarn is characterized in that the polyamide-coated elastic yarn is within a range of 40 to 80%.

In addition, in the method for producing a covered elastic yarn of the present invention, these elastic yarns and polyamide multifilament yarns are aligned and heated so that the drafted elastic yarn becomes a core yarn and the polyamide multifilament yarn becomes a sheath yarn. The false-twisting heating tension is set at 0.2 (J/d or more, the false-twisting temperature is set at 200~2
This is a method for producing a polyamide-coated elastic yarn, characterized in that false twisting is performed at 30° C. and with a false twist setting time of 0.7 seconds or more.

In the present invention having the above configuration, it is particularly preferable that the polyamide multifilament yarn is composed of a single fiber filament denier of 1.1 denier or less, and that the number of filaments is 60 or more. It is something that becomes.

Preferably, the boiling water shrinkage rate of the polyamide multifilament yarn is 4% or less, and a filament structure that satisfies these optimal conditions has better coverage, dimensional stability, and mildness. Gloss and anti-transparency can be obtained.

(effect) Hereinafter, the present invention will be roughly explained in detail.

First, to explain the coated elastic yarn of the present invention, the side profile of the yarn is a polyurethane elastic yarn as a core, surrounded by a high multifilament count of fine single filament filaments and denier, which are not found in conventional similar coated elastic yarns. The false twisted crimped polyamide filament yarn is twisted and reversed to continuously cover the yarn lengthwise in a sheath-like manner, and has a substantially non-twisted yarn structure.

In addition, the cross-sectional form of this covered elastic yarn is such that, as shown in the model diagram in FIG. The crimped yarn is coated concentrically, and a part of the crimped yarn is not structurally embedded in the elastic yarn, and has a yarn structure in which the elastic yarn and the crimped yarn can smoothly slide onto each other.

The stretch rate of the covered elastic yarn is preferably in the range of 40 to 80%, and by setting the stretch rate within this range, the stretch will not be too strong and cause discomfort to the body.

In the present invention, the polyurethane elastic thread 1 may be either a multifilament or a monofilament. Further, in order to keep the stretch rate within the above range, the draft rate of the elastic yarn and the composite plate twisting processing conditions can be appropriately set as described below.

In the covered elastic yarn of the present invention, the material of the sheath yarn may be fibers other than polyamide yarn, that is, for example, polyester yarn or other thermoplastic synthetic fiber yarn; When using fibers, the false twisting temperature of the sheath yarn must greatly exceed the melting point of the polyurethane elastic yarn, which causes the polyurethane to become brittle and result in an insufficient stretch rate. For this reason, polyamide filament yarn is practically the most suitable for the coated elastic yarn of the present invention.

If the single fiber filament denier of the filaments constituting the sheath yarn is greater than 1.5 d, the effects of the cotton-like appearance and feel that are the aim of the present invention will be diminished. Furthermore, if the number of single fiber filament yarns is less than 40, the effect of the present invention will be reduced. Therefore, the structure of the sheath yarn of the covered elastic yarn of the present invention used for clothing requires that the single fiber filament denier be 1.5 d or less and the number of filaments be 40 or more. Next, if the boiling water shrinkage rate of the filament yarn is too high, the shrinkage in the horizontal width will increase during the dyeing and finishing process after making it into a fabric, or it will be difficult to adjust the width, so it is preferable that the shrinkage rate is low. A preferred range is 6% or less, most preferably 4% or less.

Next, the method for manufacturing the covered elastic yarn of the present invention will be explained.

As already mentioned, the covered elastic yarn of the present invention is manufactured by aligning elastic yarn and polyamide multifilament yarn so that they form a core/sheath shape and twisting them into a composite plate.
Processing conditions for twisting the composite plate are particularly important requirements.

FIG. 2 is a process schematic diagram showing an embodiment of the method for manufacturing a covered elastic yarn of the present invention, in which a polyurethane filament yarn 1 and a polyamide multifilament yarn 2 stretched by a rolling roller 3 are aligned with a guide 4 and The material is arranged so as to be wrapped in a core/sheath shape and then fed to the feed roller 5 for false twisting processing.

Simultaneously heated with the false twisting spindle 7, heated with the heater 6, cooled and untwisted, then transferred from the delivery roller 8 to the cheese 9.
It is used to wind up the covered elastic yarn of the present invention. In addition, as a substitute for the rolling roller 3, a constant tension type, for example, a magnetic tension compensator may be used.

In the present invention, these elastic yarns and polyamide multifilament yarns are arranged so that the drafted elastic yarn becomes a core yarn and the polyamide multifilament yarn becomes a sheath yarn, and then supplied to a false twisting heating area. Twisting heating tension,
It is necessary to carry out false twisting at a temperature of 0.2 g/d or more, a false twisting temperature of 200 to 230'C, and a false twisting setting time of 0.7 seconds or more.

False twist heating tension is approximately determined by the draw ratio of the elastic yarn of the core yarn and the dry heat shrinkage stress of the polyamide yarn of the sheath yarn, but in order to construct a core/sheath arrangement, the core yarn tension per unit denier is determined by the sheath yarn tension. It is important to supply the product so that it is higher than the actual amount. However, when the single fiber denier of the sheath yarn to be supplied is thin and the number of sheath yarns is large, it is difficult to obtain a good false-twisted covering state only by the tension structure of both yarns, and the tension is controlled by the total heating tension of both yarns. . In terms of the specific range of false twist heating tension, it is 0.2 CI or more per unit denier, more preferably 0.25
CI or higher. In addition, when calculating the heating tension,
Since the polyurethane elastic yarn is drafted (stretched) and supplied to the heating area, the denier value is calculated by dividing the indicated denier of the polyurethane yarn by the draft ratio. In addition, the draft ratio is a value expressed as the ratio between the speed of the delivery roller in the false twisting region and the feeding speed of the polyurethane yarn, and in the process shown in FIG. The speed is the ratio of the surface speed of the rolling roller 3.

In the prior art, when using polyamide filament sheath yarn, the false twist setting temperature is usually in the range of 170 to 185 degrees Celsius, and at least 190 degrees Celsius or higher causes fusion or yarn breakage, resulting in the production of coated elastic yarns. It would have been impossible to do so. However, according to the studies of the present inventors, when the single fiber filament denier is thin in the system configuration of the sheath yarn and the number of filaments is increased at the same time, as in the present invention, it is necessary to set a high false twist heating tension. It has been found that the above-mentioned phenomena such as fusion or thread breakage become less likely to occur.

In the method of the present invention, the false twist setting temperature is suitably in the range of 200 to 230°C, more preferably about 215 to 220°C, which corresponds to the melting point of the polyamide yarn. When manufacturing false twisted covered elastic yarn, the heat setting time is usually about 0.5 seconds using conventional similar techniques, but with the same amount of time, a sufficient setting effect cannot be obtained in the present invention, and a good temporary setting time cannot be obtained. A twisted coated elastic yarn cannot be obtained. According to the findings of the present inventors, in the present invention, it is necessary to set the false twisting time to 0.7 seconds or more. However, according to various studies by the present inventors, even if the time exceeds 0.8 seconds, for example, about 1 to 2 seconds, the effect of the present invention does not increase proportionally, and the From a practical point of view such as productivity, it is most desirable to set the conditions to around 0.8 seconds.

In the method of the present invention, when both yarns are aligned and fed to the feed roller, even if the yarns are aligned, the two yarns are arranged in a merging type such that there is a large gap between the two yarns on the feed roller. It is not preferable if it is supplied. Therefore, it is possible to align both yarns on the feed roller so that there is no substantial gap between them, and to supply the yarns to the heating area while arranging them so that the elastic yarn of the core yarn is wrapped in a cylindrical shape by the sheath yarn. It is essential.

The draft ratio (stretching degree) of the polyurethane yarn should be set at around 2.5 to 4.0 times, with a focus on around 3.5 times, taking into account coverage and stretch power, and also including the false twisting feed rate. is suitable. By setting such a draft ratio, it becomes easier to realize a core-sheath structure in which the polyurethane elastic yarn becomes the core yarn and at the same time the polyamide multifilament yarn becomes the sheath yarn. Furthermore, the stretch rate of the obtained covered elastic yarn is also appropriate. Furthermore, the false twisting feed rate is -2 to -6, where the speed on the take-off side is faster than the speed on the supply side.
% underfeed range.

When the present invention is carried out using a polyamide multifilament yarn that has been subjected to air entanglement treatment as a convergence means, the coverage is slightly better than when a yarn with original twist is used as a convergence means. It may decrease. In such a case, as a solution, the covering property can be improved by applying static electricity to the filament yarn in the pulling guide 4 before feeding it to the false twisting feed roller to open the air-entangled portion and feeding it. can be improved. Static electricity can be applied electrically or by attaching fine powder made of an inorganic substance that easily absorbs moisture, such as zinc white or gypsum.

〔Effect of the invention〕

The coated elastic yarn of the present invention has a relatively low elastic recovery stress because the elastic yarn of the core yarn is subjected to sufficient heat setting at a relatively high temperature for a long period of time during false twisting, and when it becomes a product, it will be similar to the conventional one. The strong tightening of the coated elastic yarn provides a soft feel and a soft fit.

This is expressed in correspondence to the stretch rate of the covered elastic yarn, and if it is greater than 80%, which is outside the range specified by the present invention, it will be too tight, and if it is less than 40%, it will be insufficient in fit. In either case, comfortable stretchability cannot be obtained.

Further, since the sheath yarn has a single fiber filament denier of 1.5 denier or less and a large number of filaments of 40 or more, the elastic yarn of the core yarn is not visible through the sheath yarn. Therefore, when dyed, the difference in dyeing between the core thread and the sheath thread becomes less noticeable.

As for the texture, it uses ultra-fine high multifilament yarn, so it has a cotton-like soft feel and a smooth surface. As for the surface effect, it has a sparkling luster, making it ideal for applications such as tights and socks. Functionally, it has high water absorption and hygroscopicity, and is good with little "stuffy" feeling.

In addition, by using a full-dull type filament yarn, which has the lowest gloss, as the polyamide multifilament yarn, or by using a type of filament yarn with improved white skin, the anti-transparent properties can be further improved. becomes milder.

The covering form of the covered elastic yarn is such that the elastic yarn is used as the core yarn, and the monofilament filaments of the false twisted fiment yarn surround this like a concentric circle, but they substantially penetrate into the surface layer of the elastic yarn. Since the filament yarn does not impede the elongation or recovery stress of the elastic yarn, it can sufficiently exert the elongation and recovery action as a covered elastic yarn.

The coated elastic yarn of the present invention is most suitable for use in footwear such as socks, tights, pantyhose, foundations such as bodysuits, etc., where the softness and surface effect of direct contact with the skin can be taken advantage of.

(Example) Example 1 20 denier polyurethane elastic yarn stretched 3.5 times (
50 denier 40 filament polyamide multifilament yarn (boiling water shrinkage rate 5.5%) was used as the sheath yarn.
Set time: 0.8 seconds using TFT-5B type plate twisting machine manufactured by Co., Ltd.
Composite board twisting was performed under the conditions of false twist number 4500T/m, set temperature 220℃, and heating tension 0.239/d, resulting in a stretch rate of 74%, coverage index of 91%, and a good anti-transparent coating with grade 4. We were able to obtain elastic yarn.

Example 2 20 denier polyurethane elastic yarn stretched 3.4 times (
The same as in Example 1, using polyamide multifilament yarn of direct spun drawn yarn (70 denier 68 filament yarn (boiling water shrinkage rate: 4.0%)) (expressed denier) as the core yarn and air entangling treatment as the sheath yarn. The number of false twists is 32 using
00T/m, set temperature 225℃, set time 0.8 seconds,
Composite plate twisting was carried out under the conditions of a heating tension of 0.23 a/d, and it was possible to obtain a coated elastic yarn with a stretch rate of 68%, a covering index of 85%, and a transparency resistance of grade 4.

Comparative Example 20 denier polyurethane elastic yarn stretched 3.4 times (
A 70-denier 68-denier filament yarn of direct spun and drawn polyamide multifilament yarn subjected to the same air entanglement treatment as that used in Example 2 was used as the sheath yarn. False twist number 3200T/m1 using similar equipment, set temperature 185℃, set time 0
．． Composite plate twisting was carried out under the conditions of 6 seconds and heating tension of 0.15 g/d, but yarn breakage and core breakage occurred frequently and coated elastic yarn could not be obtained.

In each of the above examples, the coverage index, which is one of the evaluation factors, is practically desired to be 80% or more.

In addition, it is desirable that the anti-transparent property is level 3 or higher.

The twisting workability of the composite plate requires that yarn breakage, core breakage, fusion, etc. do not occur.

Regarding the method of measuring these values, first, the stretch rate is
Wrap the coated elastic thread 10 times in total of 4Qcm, apply a constant load of 0.1c+/d for 30 seconds, read the length Ql of the trial length, remove the load, leave it for 2 minutes, then apply a small load of 2mu/d for 30 seconds. Read the length a2 of the trial length. Stretch rate = (rLl-42>
/D, expressed as 1×100 (%). The coverage index is the length of a sample length of 1 m, hanging a load of 0.1 g/d, separating the crimped yarn and elastic yarn, and suspending a load of 0.1 g/d at the separation point. It is expressed as a percentage of redundancy.

To determine the transparency, coated elastic yarn is knitted into a 27G tubular knitted fabric, a white board and a blackboard are placed on the back side of the knitted tubular fabric, and a certain light source is applied from the front side, and the reflected light is measured using a colorimeter. Read the L value for each case, let the L value on the blackboard side be Lb, and let the L value on the whiteboard side be Lw, and use the following formula to calculate the following: 20 or more = Grade 5, 15 or more and less than 20: Classification is as follows: 4th grade, 10 or more and less than 15 = 3rd grade, 5 or more and less than 10 = 2nd grade, and less than 5 = 1st grade.

[Brief explanation of drawings]

FIG. 1 is a model diagram showing the cross-sectional shape of a covered elastic yarn according to the present invention. FIG. 2 is a process schematic diagram showing an example of the method for manufacturing the covered elastic yarn of the present invention. 1: Elastic yarn 2: Boryamide multifilament yarn 3: Elastic yarn supply roller 4: Alignment guide 5: Feed roller 6: Heater 7: False twist spindle 8: Delivery roller 9; Winding cheese patent applicant Higashi Shi Co., Ltd. Ceremony Company 1st

Claims (2)

[Claims] (1) A false-twist coated elastic yarn having a substantially non-twisted structure in which a polyurethane elastic yarn is located in the core portion and a polyamide multifilament yarn is located in the sheath portion to cover the core portion; The polyamide multifilament yarn has a single fiber filament denier of 1.5 d or less, a number of filaments of 40 or more, a boiling water shrinkage rate of 6% or less, and a stretch rate of the covered elastic yarn in the range of 40 to 80%. A polyamide-coated elastic yarn characterized by: (2) These elastic yarns and polyamide multifilament yarns are arranged so that the drafted elastic yarn becomes the core yarn and the polyamide multifilament yarn becomes the sheath yarn, and are supplied to the false twist heating area, and the false twist heating tension is applied. A method for producing a polyamide-coated elastic yarn, characterized in that false twisting is carried out at a rate of 0.2 g/d or more, a false twisting temperature of 200 to 230°C, and a false twisting set time of 0.7 seconds or more.