JP4433681B2 - Covering elastic yarn, stretch knitted fabric using the same, stockings and method for producing the same - Google Patents

Description

【００７０】
得られたストッキングの横断面を顕微鏡写真にとり、多葉断面糸の横断面の葉の頂点のなす角度αを測定した。
【００７１】
【表２】

【００７２】
表２の結果から明らかなように、本発明のカバリング弾性糸を用いたストッキングは、ソフトでさらっとした触感、軽量感、保温性に効果があることがわかる。
【００７３】
【発明の効果】
本発明によれば、ソフトでさらっとした触感、軽量感および保温性に良好なカバリング弾性糸および、ストレッチ編地、ストッキングを提供することができる。
【図面の簡単な説明】
【図１】本発明が提供する多葉断面糸の横断面形状の一例を示す横断面図であり、（ａ）は８葉、（ｂ）は６葉の例を示す。
【図２】本発明で定義した多葉断面糸の横断面形状を示す記号を説明する横断面図であり、（ａ）は８葉、（ｂ）は６葉の例を示す。
【図３】本発明で定義した多葉断面糸の葉部分形状を示す記号を説明する横断面図である。
【図４】本発明の実施例で用いた芯鞘複合糸の断面概略図である。
【符号の説明】
１：葉[0001]
BACKGROUND OF THE INVENTION
[0002]
[Field of the Invention]
TECHNICAL FIELD The present invention relates to a covering elastic yarn, a stretch knitted fabric comprising the same, a stocking, and a method for producing the same, and in particular, a covering elastic yarn excellent in lightness, heat retention, soft and smooth touch and a stretch knitted fabric comprising the same. The present invention relates to a stocking and a manufacturing method thereof.
[0003]
[Prior art]
In recent years, stretch materials using elastic yarn have gained popularity due to their good comfort. One of the stretch materials, covering elastic yarns that wrap polyamide fibers around polyurethane elastic yarns are widely used in socks, stockings, innerwear and the like.
[0004]
In order to give these products unique characteristics, the polyamide fiber, which is a wound yarn, has a modified cross-section to give it a change in texture and surface feel and to provide functionality such as water absorption and heat retention. The method has been taken.
[0005]
For example, it has been proposed to obtain a fabric having good gloss, transparency, flatness, etc. by using a deformed cross-section directly spun as a wound yarn for covering elastic yarn (Patent Document 1). Thus, it has been proposed to obtain a fabric with good heat retention (Patent Document 2).
[0006]
[Patent Document 1]
Japanese Patent Laid-Open No. 2001-181935
[Patent Document 2]
Japanese Patent Laid-Open No. 8-134701
[Problems to be solved by the invention]
However, with the covering elastic yarn according to the prior art having a modified cross section, a soft texture can be obtained, but a smooth touch and heat retention cannot be obtained. In addition, with the covering elastic yarn according to the prior art of hollow cross-section, heat retention is obtained, but it is difficult to produce a polyamide hollow fiber with a single yarn fineness of 1.5 dtex or less, so the single yarn fineness becomes thick and soft texture is obtained. Couldn't get.
[0009]
On the other hand, when using a modified cross-section yarn such as Y-type or T-type to obtain a light touch, the conventional method of direct spinning from a deformed die has a low surface viscosity due to the low viscosity of the polymer immediately after the die is discharged. The cross-sectional shape is rounded by the action of lowering the thickness, and satisfaction with the smooth touch is not obtained.
[0010]
In view of the background of the prior art, the present invention provides a new technique in which a deformed cross-sectional yarn that is more effective in tactile feel than before has been developed for the first time in a high-order processing step, and a cross-sectional shape that cannot be obtained at the spinning stage can be obtained. It is intended to provide a covering elastic yarn excellent in smooth touch, heat retention and light weight, a stretch knitted fabric comprising the same, a stocking and a method for producing the same.
[0011]
[Means for Solving the Problems]
In order to solve the above problems, the present invention mainly comprises the following configuration. That is, the covering elastic yarn of the present invention is a covering elastic yarn in which a polyamide fiber is wound around a core yarn made of an elastic fiber, wherein the polyamide fiber is a multi-leaf section filament yarn, and the multi-leaf The cross-section of the cross-section filament yarn has a shape having three or more leaves whose angle α formed by the apex of the leaf is 90 ° or less, and the multi-leaf cross-section filament yarn has the following formulas (1) to (2) It is characterized by satisfying.
(1) 0.5r ≦ a _max
(However, the circumscribed circle radius of the filament cross-section is r, and each leaf of the filament cross-section shares two points B _i (common to C _i -1), C _i (common to B _{i + 1} )) There is the longest ones a _max of line segments are connected by apexes T _i of each leaf, respectively.)
(2) Σ2S _i / K _i L _i N ≦ 1.5
(However, the length of the line segment B _i C _i connecting the two points B _i (common to C _i -1) and C _i (common to B _{i + 1} ) that each leaf of the filament cross section constitutes the adjacent leaf. K _i , the area of the portion where each leaf is cut out by the line segment B _i C _i is S _i , the distance between the vertex of each leaf and the line segment B _i C _i is L _i, and the leaf of the filament cross section The number of N is assumed to be N).
[0012]
In addition, the stretch knitted fabric and stockings of the present invention are configured using such a covering elastic yarn. Such a stretch knitted fabric and stocking manufacturing method includes a core-sheath type composite filament yarn having a core component of nylon 6 or nylon 66, a multi-leaf cross-sectional shape, and a sheath component of polyester, and a core of elastic fiber. Wrapping around the yarn to produce a covering elastic yarn, then knitting a stretch knitted fabric using this covering elastic yarn, or knitting a stocking, and then subjecting them to alkali weight reduction processing It is.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
The present invention has been eagerly studied for such problems, that is, a covering elastic yarn excellent in soft and smooth tactile sensation, heat retention and lightness, and a stretch knitted fabric and stockings, and has a modified cross section that is more effective for tactile sensation than before. When a new technique was adopted in which the yarn was first expressed in the high-order processing step and a cross-sectional shape that could not be obtained at the spinning stage was adopted, it was clarified that this problem could be solved for the first time.
[0014]
Hereinafter, the present invention will be described in detail.
[0015]
The covering elastic yarn that is the subject of the present invention may be a single covering elastic yarn or a double covering elastic yarn. The single covering elastic yarn is a composite elastic yarn in which a covering yarn is wound around the elastic fiber yarn in a single layer. The double covering elastic yarn is a composite elastic yarn obtained by wrapping a covering yarn around the elastic fiber yarn twice in different directions or in the same direction.
[0016]
In addition, as the elastic fiber serving as the core yarn of the covering elastic yarn, polyurethane elastic fiber, polyamide elastic fiber, polyester elastic fiber, natural rubber fiber, synthetic rubber fiber, butadiene fiber, etc. are used. From the viewpoint of elastic properties, thermal properties, durability, etc., polyurethane elastic fibers and polyamide elastic fibers are preferred.
[0017]
The fineness of these elastic fibers is not particularly limited. For example, in the case of stockings, the fineness varies depending on the setting of the tightening pressure, but may generally be in the range of about 8 to 80 dtex. Within such a range, the yarn strength is sufficient, and troubles such as core yarn breakage are unlikely to occur during covering and knitting, and the stretchability and durability as stockings are sufficient, while the tightening force does not become too strong.
[0018]
In the present invention, this elastic fiber is used as a core yarn, and a polyamide fiber is wound around it to form a covering elastic yarn.
[0019]
The polyamide fiber constituting the covering elastic yarn of the present invention has a multi-leaf cross-sectional shape in which the cross section thereof has three or more leaves having an angle α formed by the apex of the leaves of 90 ° or less, and preferably the number of leaves is 5 or more. Here, the leaf refers to a portion that is a convex protrusion in the cross section, as indicated by reference numeral 1 in FIG. In addition, the angle α is an angle B _i T _i formed by the vertex T _i of the leaf and two points B _i (common to C _i -1) and C _i (common to B _{i + 1} ) that each leaf shares with the adjacent leaf. Define C _i .
[0020]
When the angle α formed by the apex of the leaf is less than 90 °, the number of the leaves is 2 or less, and when the woven or knitted fabric is formed, the protruding portion does not sufficiently protrude to the surface, and the soft touch is impaired. . The angle formed by the apex of the leaf can be obtained by taking a cross section of the yarn in a photomicrograph and measuring the angle.
[0021]
The radius of the circumscribed circle of the filament cross-section is r, and each leaf of the filament cross-section shares two points B _i (common to C _i -1) and C _i (common to B _{i + 1} ). The longest line segment connected by the vertices T _i is defined as a _max as shown in FIGS. At this time, the filament in the present invention is
(1) 0.5r ≦ a _max
Is to satisfy
Preferably 0.6r ≦ a _max , more preferably 0.7r ≦ a _max .
[0022]
When 0.5r> a _max , since the leaf length is small, it is not possible to obtain a soft and crisp feel, lightness and heat retention.
[0023]
In addition, the length of a line segment B _i C _i connecting two points B _i (common to C _i -1) and C _i (common to B _{i + 1} ) that each leaf of the filament cross-section configures with the adjacent leaf Let K _i be the area of the portion where each leaf is cut by line segment B _i C _i , S _i , the distance between the apex of each leaf and line segment B _i C _{i be} L _i, and let the number of leaves in the filament cross section be When N, the filament in the present invention is (2) Σ2S _i / K _i L _i N ≦ 1.5
Is to satisfy
Preferably, Σ2S _i / K _i L _i N ≦ 1.35, and more preferably, Σ 2S _i / K _i L _i N ≦ 1.2.
[0024]
When the _{Σ2S i / K i L i N} > 1.5 , because the leaves rounded, it is impossible to obtain a tactile and smooth soft.
[0025]
For S _i , K _i , L _i , and N, the yarn is cut perpendicularly to the fiber length direction, the cut surface is observed with an SEM, photographed, and the copied cross-section has the area and length It can be obtained by actually measuring the thickness. From the actually measured values, S _i / K _i L _i N is calculated for i = 1 to N, respectively, and the sum is calculated to obtain Σ2S _i / K _i L _i N. For example, in the case of Figure 2 _{(a), S 1, K} 1, L 1, S 2, K 2, L 2 ···· actually measuring the _{S 8, K 8, L 8} , S 1 / K 1 L ₁ N, S ₂ / K ₂ L ₂ N... S ₈ / K ₈ L ₈ N are calculated and summed to obtain Σ2S _i / K _i L _i N. The number of leaves is 3 or more, and preferably the number of leaves is 5 or more. Here, the leaf refers to a portion that is a convex protrusion in the cross section, as indicated by reference numeral 1 in FIG. In addition, the angle α is an angle B _i T _i formed by the vertex T _i of the leaf and two points B _i (common to C _i -1) and C _i (common to B _{i + 1} ) that each leaf shares with the adjacent leaf. Define C _i .
[0026]
There is no particular limitation on the single yarn fineness and the yarn fineness of the polyamide fiber constituting the covering elastic yarn of the present invention, but it is preferable that the single yarn fineness is 2 dtex or less in order to obtain a soft and smooth feel.
[0027]
Although the manufacturing method of the covering elastic yarn of this invention is not specifically limited, For example, it manufactures using the following methods.
[0028]
In the production method, polyamide is arranged in a multi-leaf cross-sectional shape at the core, and a spinneret designed to arrange polyester in the sheath is used. After melt spinning, refueling and entanglement are performed, and 1000 m / Spinning-up at a speed of at least min, and then stretching and winding, or after melt spinning, refueling and entanglement treatment, spinning at a speed of at least 1000 m / min and winding without substantial stretching It is preferable to carry out by a method. More preferably, the winding speed is 3000 m / min or more in terms of productivity. Thereafter, various yarn processing such as false twisting and blending may be performed within a range not impairing the object of the present invention.
[0029]
Moreover, the polymer which comprises a sheath component will not be specifically limited if it is a polymer which melt | dissolves by an alkali elution process, For example, polyesters, such as a polyethylene terephthalate, a polybutylene terephthalate, a polypropylene terephthalate, a polylactic acid, are preferable. In addition, these polymers can be copolymerized or contain additives as necessary in order to accelerate the alkali elution rate.
[0030]
Moreover, the polymer which comprises a core component will not be specifically limited if it is a polyamide, For example, nylon 6 and nylon 66 are preferable. Various additives may be included as long as the object of the present invention is not impaired. Examples of this additive include antioxidants, heat stabilizers, plasticizers, flame retardants, conductivity-imparting agents, hygroscopic agents, and antibacterial agents.
[0031]
In the covering elastic yarn of the present invention, the polyester / polyamide core-sheath composite fiber described above is wound around the elastic yarn by a normal covering machine. The number of windings (hereinafter referred to as the number of twists) is not particularly limited. For example, in the case of a single covering elastic yarn, 500 to 4000 t / m is preferable from the viewpoint of softness. More preferably, it is 600-2500 t / m.
[0032]
Then, after knitting, the sheath component polyester can be dissolved by alkali elution treatment to leave a multi-leaf cross-section core component. The type of alkali used for the alkali elution treatment is not particularly limited as long as it is a strong alkali such as sodium hydroxide, potassium hydroxide or lithium hydroxide, but sodium hydroxide is preferably used. Alkaline treatment conditions are determined by the alkali concentration, treatment time, and treatment temperature, but it is desirable that the alkali concentration is 30 to 40 g / L and the treatment temperature is in the range of 80 to 120 ° C. Further, weight loss accelerators such as quaternary ammonium salts and cationic activators are known for increasing the alkali elution rate, and they may be used in combination as long as they do not impair the properties of the covering elastic yarn.
[0033]
The merit of using such a method is that the core component is surrounded by the sheath component, so that the core component is prevented from being rounded to reduce the surface tension and maintains a sharp shape. There is something you can do.
[0034]
Further, from the viewpoint of preventing the core component from becoming round, it is desirable that the polymer used for the sheath component has a higher viscosity than the polymer used for the core component. Further, the cross section of the yarn before elution of the sheath component may be round, square, flat, Y-shaped or any other shape, but a circle is preferable from the viewpoint of maintaining the shape of the core component.
[0035]
The stretch knitted fabric targeted by the present invention is not particularly limited, but a single circular knitted fabric or double circular knitted fabric which is a circular knitted fabric, a single tricot knitted fabric or double tricot knitted fabric which is a warp knitted fabric, a single There are raschel knitted fabrics and double raschel knitted fabrics, and these can be knitted by each dedicated knitting machine. The knitting structure is not particularly limited, such as a circular knitted fabric, interlock structure, jacquard structure, warp knitted fabric half structure, satin structure, jacquard structure, and the like.
[0036]
The stockings which are the subject of the present invention are stockings products represented by pantyhose, long stockings, short stockings and tights.
[0037]
In the stocking of the present invention, it is preferable that the knitted fabric of at least the leg portion of such a stocking is knitted only with the covering elastic yarn or the covering elastic yarn and the polyamide fiber are alternately knitted in order to obtain a good fit. The leg knitted fabric may be provided with a knitted pattern made of other materials or a one-point decoration.
[0038]
The stockings of the present invention are knitted by a known manufacturing method. For example, when knitting with only covering elastic yarns, a knitting machine with two or four ports may be used, and knitting may be performed by a normal method in which only covering elastic yarns are supplied for knitting. In the case of the single covering elastic yarn, the single covering elastic yarn of S direction covering and the single covering elastic yarn of Z direction covering are knitted alternately. What is necessary is just to make it the stocking product of this invention by heat-treating the obtained knitted fabric.
[0039]
【Example】
Hereinafter, the present invention will be described in more detail with reference to examples. The physical properties are measured as follows.
A. It was left for 2 hours in a room adjusted to a soft feeling temperature of 25 ° C. and a humidity of 50%, and the sensory evaluation was performed on ten persons with respect to the soft feeling of the knitted fabric. Evaluation was performed as follows.
[0040]
There is a soft feeling: ○, soft feeling is not enough: Δ, soft feeling is not good: ×.
B. The knitted fabric was left to stand for 2 hours in a room adjusted to a temperature of 25 ° C. and a humidity of 50%. Evaluation was performed as follows.
[0041]
There is a crisp feeling: ◯, the crisp feeling is not enough: △, there is no wiping feeling: x.
C. The knitted fabric was left for 2 hours in a room adjusted to a light weight temperature of 25 ° C. and a humidity of 50%. Evaluation was performed as follows.
[0042]
There is a feeling of lightness: ○, the feeling of lightness is not enough: Δ, there is no feeling of lightness: ×.
D. The sample was left for 2 hours in a room adjusted to a heat retention temperature of 10 ° C. and a humidity of 30%. Evaluation was performed as follows.
[0043]
There is heat insulation: ○, heat insulation is not sufficient: Δ, heat insulation is not good: ×.
[0044]
Example 1
Using a spinneret designed to place nylon 6 with 98% sulfuric acid relative viscosity of 2.6 in the 8-leaf star core and polyethylene terephthalate in the sheath, a weight ratio of 30:70, spinning temperature of 290 ° C. , Melted and discharged, cooled, lubricated, entangled, taken up with a non-heated roller, drawn 1.4 times with a roller heated to 160 ° C., taken up at a take-up speed of 4000 m / min, 56 dtex A core-sheath composite yarn having the shape shown in FIG. 4 having 18 filaments was obtained.
[0045]
The obtained core-sheath composite yarn is made of Toray DuPont's “Lycra” 20 dtex, and is single-covered in the S direction or Z direction with a draft of 2.9 and a twist number of 1000 t / m, and the S direction single covering elasticity Yarn and Z-direction single covering elastic yarn were produced.
[0046]
Using the obtained single-covering elastic yarn, the S-direction single covering elastic yarn and the Z-direction single covering elastic yarn are fed alternately to the super 4-knitting machine (400 needles) manufactured by Nagata Seiki Co., Ltd. The yarn was supplied to the yarn mouth, and the leg knitted fabric was knitted only with the covering elastic yarn.
[0047]
The obtained knitted fabric was completely dissolved in polyethylene terephthalate using caustic soda 60 g / L.
[0048]
Table 1 shows the eight-leaf cross-sectional shape thus obtained.
[0049]
Subsequently, dyeing with a drum dyeing machine at 3% by weight of acidic dye (Lanasyn S Black S-DL 120 (manufactured by Clariant Japan Co., Ltd.)), a heating rate of 1 ° C./min, a dyeing temperature of 95 ° C., and a dyeing time of 30 minutes. Next, FIX treatment was performed with 3% by weight of Dimafix ESH (manufactured by Meisei Chemical Co., Ltd.), a treatment temperature of 80 ° C., and a treatment time of 20 minutes. Subsequently, 4% by weight of Nikka Silicon AMO (manufactured by Nikka Chemical Co., Ltd.) was subjected to a flexible finishing process at a processing temperature of 40 ° C. and a processing time of 20 minutes, followed by a foot shape finishing set at 110 ° C. to obtain a stocking product.
[0050]
Table 2 shows the results of evaluating the softness, lightness, and heat retention of the leg part of the obtained stocking product.
[0051]
Example 2
Spinning was performed in the same manner as in Example 1 except that the discharge weight ratio of nylon 6 and polyethylene terephthalate was set to 45:55, and a covering elastic yarn was produced to obtain a stocking.
[0052]
Table 1 shows the obtained Yaba cross-sectional shape, and Table 2 shows the results of evaluation of the knitted fabric.
[0053]
Example 3
Spinning was performed in the same manner as in Example 1 except that the discharge weight ratio of nylon 6 and polyethylene terephthalate was set to 35:65, and a covering elastic yarn was produced to obtain a stocking.
[0054]
Table 1 shows the obtained Yaba cross-sectional shape, and Table 2 shows the results of evaluation of the knitted fabric.
[0055]
Example 4
Spinning was performed in the same manner as in Example 1 except that the core component polymer was nylon 66 having a 98% sulfuric acid relative viscosity of 2.6, and a covering elastic yarn was produced to obtain a stocking.
[0056]
Table 1 shows the obtained Yaba cross-sectional shape, and Table 2 shows the results of evaluation of the knitted fabric.
[0057]
Example 5
Spinning was performed in the same manner as in Example 1 except that the polymer of the sheath component was poly L-lactic acid (L-form ratio: 95%, D-form ratio: 5%), and a covering elastic yarn was produced to obtain a stocking.
[0058]
Table 1 shows the obtained Yaba cross-sectional shape, and Table 2 shows the results of evaluation of the knitted fabric.
[0059]
Comparative Example 1
Changing the shape of the hole through which the core component of the spinneret is discharged, spinning is performed in the same manner as in Example 1 except that the discharge weight ratio of nylon 6 and polyethylene terephthalate is 45:55, to produce a covering elastic yarn, Got stockings.
[0060]
Table 1 shows the obtained Yaba cross-sectional shape, and Table 2 shows the results of evaluation of the knitted fabric.
[0061]
Comparative Example 2
Changing the shape of the hole through which the core component of the spinneret is discharged, spinning is performed in the same manner as in Example 1 except that the discharge weight ratio of nylon 6 and polyethylene terephthalate is 50:50 to produce a covering elastic yarn, Got stockings.
[0062]
Table 1 shows the obtained Yaba cross-sectional shape, and Table 2 shows the results of evaluation of the knitted fabric.
[0063]
Comparative Example 3
Nylon 6 with a 98% sulfuric acid relative viscosity of 2.6 is melted and discharged at a spinning temperature of 270 ° C. using a + bore spinneret, cooled, lubricated, entangled, and taken up with a non-heated roller. Spinning was carried out in the same manner as in Example 1 except that a convex square section yarn of 33 dtex 36 filament was obtained by drawing 1.5 times between them and winding at a winding speed of 4000 m / min. Manufactured and got stockings.
[0064]
Table 2 shows the results of evaluating the obtained knitted fabric.
[0065]
Comparative Example 4
Nylon 6 of 98% sulfuric acid relative viscosity 2.6 is melted and discharged at a spinning temperature of 270 ° C. using a Y-hole spinneret, cooled, lubricated, entangled, and taken up by a non-heated roller. A covered elastic yarn was produced by spinning in the same manner as in Example 1 except that the yarn was stretched 1.5 times and wound at a winding speed of 4000 m / min, and a Y-shaped cross-section yarn of 33 dtex 36 filament was obtained. And got stockings.
[0066]
Table 2 shows the results of evaluating the obtained knitted fabric.
[0067]
Comparative Example 5
Nylon 6 with 98% sulfuric acid relative viscosity 2.9 is melted and discharged at a spinning temperature of 270 ° C. using a spinneret composed of eight slits in a round hole. Spinning in the same manner as in Example 1 except that it was stretched 1.5 times with a heating roller at 155 ° C. and wound at a winding speed of 4000 m / min to obtain a hollow section yarn of 28 dtex 12 filaments. Then, a covering elastic yarn was manufactured to obtain a stocking.
[0068]
Table 2 shows the results of evaluating the obtained knitted fabric.
[0069]
[Table 1]

[0070]
The cross section of the stocking obtained was taken as a photomicrograph, and the angle α formed by the apex of the leaf of the cross section of the multileaf section yarn was measured.
[0071]
[Table 2]

[0072]
As is apparent from the results in Table 2, it can be seen that the stockings using the covering elastic yarn of the present invention are effective in soft and light touch, lightness and heat retention.
[0073]
【The invention's effect】
According to the present invention, it is possible to provide a covering elastic yarn, a stretch knitted fabric, and a stocking that are soft and smooth in touch, lightweight, and have good heat retention.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing an example of the cross-sectional shape of a multi-leaf cross-section yarn provided by the present invention, where (a) shows 8 leaves and (b) shows 6 leaves.
FIGS. 2A and 2B are cross-sectional views for explaining symbols indicating the cross-sectional shape of a multi-leaf cross-sectional yarn defined in the present invention. FIG. 2A shows an example of 8 leaves, and FIG. 2B shows an example of 6 leaves.
FIG. 3 is a cross-sectional view for explaining symbols indicating the leaf shape of a multi-leaf section thread defined in the present invention.
FIG. 4 is a schematic cross-sectional view of a core-sheath composite yarn used in an example of the present invention.
[Explanation of symbols]
1: leaves

Claims (6)

In a covering elastic yarn in which a polyamide fiber is wound around a core yarn made of an elastic fiber, the polyamide fiber is a multi-leaf section filament yarn, and the cross-section of the multi-leaf section filament yarn is a leaf It has a shape having three or more leaves whose angle α formed by the apex is 90 ° or less, and the multi-leaf section filament yarn satisfies the following formulas (1) to (2): Covering elastic yarn.
(1) 0.5r ≦ a _max
(However, the circumscribed radius of the filament cross section is r, and each leaf of the filament cross section shares two points B _i (common to C _i -1) and C _i (common to B _{i + 1} )). and a _max longest ones of line segments are connected by apexes T _i of each lobe.)
(2) Σ2S _i / K _i L _i N ≦ 1.5
(However, the length of the line segment B _i C _i connecting the two points B _i (common to C _i -1) and C _i (common to B _{i + 1} ) that each leaf of the filament cross section constitutes the adjacent leaf is represented by K and _i, the area of a portion where each leaf is cut at the line segment B _i C _i S _i, the number of distance leaves with was L _i. the filament cross section of the vertices and segments B _i C _i of each lobe Is N.) A stretch knitted fabric comprising the covering elastic yarn according to claim 1. At least a leg part is comprised using the covering elastic yarn of Claim 1, The stocking characterized by the above-mentioned. At least a leg part is comprised by knitting | covering the covering elastic yarn and polyamide continuous fiber of Claim 1 alternately, The stocking characterized by the above-mentioned. The core component is nylon 6 or nylon 66, has a multi- leaf cross-sectional shape, and has a shape having three or more leaves having an apex angle α of 90 ° or less. 1) to (2) are satisfied, and a covering elastic yarn is manufactured by wrapping a core-sheath type composite filament yarn having a sheath component made of polyester around a core yarn made of elastic fiber, and then the covering elasticity. A method for producing a stretch knitted fabric, comprising knitting a stretch knitted fabric using yarn and then subjecting the stretch knitted fabric to an alkali weight reduction process.
(1) 0.5r ≦ a _max
(However, the circumscribed radius of the cross section of nylon 6 or nylon 66 is r, and two points B _i ( common to C _i -1) that each leaf in the cross section shares with the adjacent leaf ), C _i (B _{i + 1} and common) each of which the longest ones a _max of line segments are connected by apexes T _i of each lobe.)
(2) Σ2S _i / K _i L _i N ≦ 1.5
(However, the line segment B _i C _i connecting two points B _i ( common to C _i -1) and C _i ( common to B _{i + 1} ) each leaf of the nylon 6 or nylon 66 cross section constitutes the adjacent leaf . The length is K _i , the area of the portion where each leaf is cut off by line segment B _i C _i is S _i , and the distance between the apex of each leaf and line segment B _i C _i is L _i, and nylon 6 or nylon 66. Let N be the number of leaves in the cross section. The core component is nylon 6 or nylon 66, has a multi- leaf cross-sectional shape, and has a shape having three or more leaves having an apex angle α of 90 ° or less. 1) to (2) are satisfied, and a covering elastic yarn is manufactured by wrapping a core-sheath type composite filament yarn having a sheath component made of polyester around a core yarn made of elastic fiber, and then the covering elasticity. A method of manufacturing a stocking, comprising knitting a stocking using a thread and then subjecting the stocking to an alkali weight reduction process.
(1) 0.5r ≦ a _max
(However, the circumscribed radius of the cross section of nylon 6 or nylon 66 is r, and two points B _i ( common to C _i -1) that each leaf in the cross section shares with the adjacent leaf ), C _i (B _{i + 1} and common) each of which the longest ones a _max of line segments are connected by apexes T _i of each lobe.)
(2) Σ2S _i / K _i L _i N ≦ 1.5
(However, the line segment B _i C _i connecting two points B _i ( common to C _i -1) and C _i ( common to B _{i + 1} ) each leaf of the nylon 6 or nylon 66 cross section constitutes the adjacent leaf . The length is K _i , the area of the portion where each leaf is cut off by line segment B _i C _i is S _i , and the distance between the apex of each leaf and line segment B _i C _i is L _i, and nylon 6 or nylon 66. Let N be the number of leaves in the cross section.

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