JP2009068147A - Covered elastic yarn - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a covered elastic yarn providing a fabric having a flat surface feeling and excellent stretchability when used for clothes or the like by carrying out high-order processing. <P>SOLUTION: The covered elastic yarn is composed of a core yarn and a sheath yarn. In the covered elastic yarn, polyurethane-based elastic fibers are used as the core yarn and an actual crimped yarn is used as the sheath yarn. The actual crimped yarn is composed of polyester-based conjugated fibers which are a side-by-side type or an eccentric core-sheath type. In the polyester-based conjugated fibers, one of constituent components comprises polyethylene terephthalate as a main component and the other thereof comprises polytrimethylene terephthalate as a main component. The actual crimped yarn satisfies following (1) to (3): (1)≥100% stretch elongation, (2)≥25 peaks/25 mm number of crimps of single filaments and (3)≤10% shrinkage percentage in boiling water. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a coated elastic yarn in which an actual crimped yarn having a helical crimp structure with a small radius of curvature is wound around a polyurethane elastic yarn, and particularly relates to a coated elastic yarn excellent in elongation recovery.

Conventionally, many proposals regarding covered elastic yarns aimed at high stretchability have been made. For example, a method has been proposed in which a polyurethane elastic yarn and an inelastic yarn are twisted (first twisted) and then false twisted (see Patent Document 1). Although such a method improves elongation recovery, it has often been pointed out that after twisting, torque is generated in the yarn, handling is not good, and the cost is industrially high. Furthermore, a polyester-based composite having a polyurethane elastic fiber as the core yarn and one of the constituent components as the main component of the sheath yarn is polyethylene terephthalate, and the other component is a side-by-side type or an eccentric core-sheath type whose main component is polytrimethylene terephthalate. A coated elastic yarn using fibers has been proposed (see Patent Document 2). Although this method has improved the stretchability of the fabric, it cannot be said to be sufficient particularly in the field where the pressure and the motion following ability are required, such as a sports inner, and further improvement is required for the stretchability of the coated elastic yarn. It has been.
JP 11-241240 A JP 2003-119632 A

  An object of the present invention is to provide a coated elastic yarn that can be subjected to high-order processing to obtain a highly stretchable fabric when used for clothes or the like.

The actual crimped yarn of the present invention has the following configuration.
That is, it is a coated elastic yarn composed of a core yarn and a sheath yarn, and polyurethane-based elastic fibers are used for the core yarn. One of the constituent components of the sheath yarn is mainly composed of polyethylene terephthalate, and the other is mainly composed of polytrimethylene terephthalate. A coated elastic yarn comprising a polyester-based composite fiber which is a side-by-side type or an eccentric core-sheath type as a component, and which uses an actual crimped yarn satisfying the following (1) to (3).
-Stretch rate is 100% or more-Single filament has 25 crimps / 25mm or more-Hot water shrinkage rate is 10% or less

  The coated elastic yarn of the present invention is to provide a coated elastic yarn capable of obtaining a fabric excellent in stretchability when subjected to high-order processing and used for clothes or the like.

The coated elastic yarn of the present invention is a coated elastic yarn composed of a core yarn and a sheath yarn, and a polyurethane-based elastic fiber is used for the core yarn. One of the constituent components is polyethylene terephthalate as a main component and the other is a sheath yarn. It is made of a polyester-based composite fiber that is a side-by-side type or an eccentric core-sheath type mainly composed of polytrimethylene terephthalate, and is characterized by using an actual crimped yarn that satisfies the following (1) to (3). It is a coated elastic yarn.
(1) The stretch elongation rate is 100% or more, the number of crimps of a single filament is 25 peaks / 25 mm or more, and the hot water shrinkage rate is 10% or less. The coated elastic yarn of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic side view showing an example of the coated elastic yarn of the present invention.

  The coated elastic yarn (A) of the present invention shown in FIG. 1 is a side-by-side type or eccentric type in which one of the constituent components is a main component of polyethylene terephthalate and the other is a main component of polytrimethylene terephthalate. It has a structure in which an actual crimped yarn (c) made of a polyester-based composite fiber that is a core-sheath type is wound once or twice.

  The polyurethane elastic yarn (b) used in the present invention is obtained by spinning a polyurethane polymer obtained by reacting a polymer diol, an isocyanate mainly composed of an organic diisocyanate, and a polyfunctional active hydrogen compound. preferable.

  Examples of the polymer diol used in the present invention include polyether glycols such as polytetramethylene glycol, polyethylene glycol, and propylene ether glycol, ethylene glycol, 1,6-hexanediol, 1,4-butanediol, neopentyl glycol, and the like. Polyester glycols obtained by reacting at least one glycol with at least one dicarboxylic acid such as adipic acid, suberic acid, azelaic acid, sebacic acid, β-methyladipic acid, isophthalic acid, polycaprolactone glycol, polyhexamethylene Examples include one or a mixture or copolymer of two or more polymer diols such as dicarbonate glycol.

  Examples of the isocyanate mainly composed of organic diisocyanate used in the present invention include 4,4′-diphenylmethane diisocyanate, 1,5-naphthalene diisocyanate, 1,4-phenylene diisocyanate, 2,4-tolylene diisocyanate, hexamethylene diisocyanate, Examples thereof include one or a mixture of two or more organic diisocyanates such as 1,4-cyclohexane diisocyanate, 4,4′-dicyclohexylmethane diisocyanate, and isophorone diisocyanate. Further, a small amount of triisocyanate may be used in combination.

  Examples of the polyfunctional active hydrogen compound used in the present invention include ethylenediamine, 1,2-propylenediamine, hexamethylenediamine, xylylenediamine, 4,4′-diphenylmethanediamine, hydrazine, 1,4-diaminopiperazine, ethylene glycol, 1 1, 4-butanediol, 1,6-hexanediol, water and the like, or a mixture of two or more of these. If desired, these compounds may be used in combination with a terminator such as a monoamine or monoalcohol in a small amount.

  Polyurethane polymers include 2,6-ditetrabutylparacresol, antioxidants such as phosphites, light or ultraviolet absorbers such as hydroxybenzophenone or hydroxybenzothiazole, 1,1-dialkyl substituted Gas yellowing and degradation inhibitors such as semicarbazide and dithiocarbamate, and white pigments such as titanium oxide and zinc oxide may be used as appropriate.

  The polyethylene terephthalate used for the polyester composite fiber is composed of a polymer component having an ethylene terephthalate unit as a main repeating unit. That is, a polyester obtained using terephthalic acid as the main acid component and ethylene glycol as the main glycol component is preferable. The copolymerization component which can form another ester bond may be contained in the ratio of 20 mol% or less, Preferably it is contained in the ratio of 10 mol% or less. Examples of the copolymerizable compounds include isophthalic acid, succinic acid, cyclohexanedicarboxylic acid, adipic acid, diamic acid, sebacic acid, dicarboxylic acids such as 5-sodiumsulfoisophthalic acid, triethylene glycol, polyethylene glycol, propanediol, and butanediol. Diols such as pentanediol, hydroquinone and bisphenol A can be used. If necessary, titanium dioxide as a matting agent, fine particles of silica or alumina as a lubricant, hindered phenol derivatives, coloring pigments as an antioxidant may be added.

  The polytrimethylene terephthalate used for the polyester-based composite fiber is composed of a polymer component having a trimethylene terephthalate unit as a main repeating unit. That is, a polyester obtained using terephthalic acid as the main acid component and 1,3-propanediol as the main glycol component is preferable. The copolymerization component which can form another ester bond may be contained in the ratio of 20 mol% or less, Preferably it is contained in the ratio of 10 mol% or less. As copolymerizable compounds, dicarboxylic acids such as isophthalic acid, succinic acid, cyclohexanedicarboxylic acid, adipic acid, dimer acid, sebacic acid, 5-sodium sulfoisophthalic acid, ethylene glycol, diethylene glycol, butanediol, neopentyl glycol, cyclohexane Diols such as dimethanol, polyethylene glycol and polypropylene glycol can be used.

  Polytrimethylene terephthalate has the same mechanical and chemical properties as polyethylene terephthalate and polybutylene terephthalate, which are typical polyester filaments, and is extremely excellent in stretch recovery. This is because the methylene chain of the alkylene glycol part in the polytrimethylene terephthalate crystal structure has a Gauche-Gauche structure (the molecular chain bends at 90 degrees), and is further constrained by the interaction between benzene rings (stacking, parallel). It is thought that the molecular chain is easily stretched and recovered by the rotation of the methylene group because the point density is low and the flexibility is high.

  In the present invention, the polyester-based composite fiber contains the above-described polyethylene terephthalate as the maximum weight component (that is, the main component) of the one component, and the polytrimethylene terephthalate as described above is the other component. Contains as a maximum weight component in the component. In other words, if necessary, the polyester composite fiber may be added with titanium dioxide as a matting agent, silica or alumina fine particles as a lubricant, hindered phenol derivatives, coloring pigments as an antioxidant, and the like. Good.

  In the present invention, the polyester-based composite fiber as described above is a side-by-side type or an eccentric core-sheath type. If it is not a side-by-side type or an eccentric core-sheath type, there is a problem that when heat is applied to the yarn, a coiled helical crimp does not appear and the yarn cannot be provided with elasticity.

  Next, the actual crimped yarn will be described. Originally, a polyester-based composite fiber in which at least two kinds of polyester components are simply bonded to a side-by-side type or an eccentric core-sheath type is called a latent crimped yarn or a semi-crimped crimped yarn. A difference in thermal shrinkage occurs between the component and the low shrinkage component, and the high viscosity side shrinks greatly, so that distortion occurs in the single fiber, and a three-dimensional coiled helical crimp (d) appears. The actual crimped yarn (c) used in the present invention is a latent crimped yarn or a semi-explicit crimped yarn that is subjected to tension heat treatment or false twist to express a helical crimp (d), and is manifested. As a means of tension heat treatment, the polyester composite fiber bonded with the above-mentioned two kinds of polyester components is subjected to tension heat treatment at a temperature of about 75 to 190 ° C. at which the glass transition point or higher does not cause thermal embrittlement using a heater such as a hot pin or a hot plate. It is preferable to apply.

  The actual crimped yarn used in the present invention obtained as described above has a stretch / elongation rate of 100% or more. When the stretch / elongation rate is less than 100%, a desired stretch feeling cannot be obtained when the fabric is formed. On the other hand, the upper limit of the stretch / elongation rate is not particularly limited, but is generally about 230%.

  Further, the actual crimped yarn used in the present invention obtained as described above has a single filament crimp number of 25 threads / 25 mm or more. In the actual crimped yarn, it is indispensable to express a fine helical crimp in order to exhibit good stretchability and to obtain a beautiful surface feeling when formed into a fabric. That is, it is necessary that the number of crimps of the single filament is 25 peaks / 25 mm or more. On the other hand, the upper limit of the number of crimps of the single filament is not particularly limited, but is generally about 80 peaks / 25 mm.

  Furthermore, the actual crimped yarn used in the present invention obtained as described above has a hot water shrinkage of 10% or less. When the hot water shrinkage rate is greater than 10%, the shrinkage amount of the fabric increases in processes such as refining and dyeing after weaving, and the fabric surface is wrinkled, resulting in poor appearance quality or a fabric with a thick fabric.

  The coated elastic yarn of the present invention preferably has an elongation recovery rate of 80% or more at 20% elongation. When the stretch recovery rate at 20% elongation is less than 80%, desired stretch feeling and kickback feeling may not be obtained when fabric is produced. On the other hand, the upper limit of the elongation recovery rate at 20% elongation is not particularly limited, but is generally about 95%.

  Further, in the present invention, in order to obtain appropriate kickback properties and stretch properties, the intrinsic viscosity of each component of the polyester-based composite fiber is different, and the intrinsic viscosity [ηb] of the low-viscosity polyester and the high-viscosity side are different. The intrinsic viscosity ratio ([ηb] / [ηa]) to the polyester intrinsic viscosity [ηa] is preferably 0.3 to 0.8.

  By bonding two polymers having different intrinsic viscosities in this way, stress tends to concentrate on the high viscosity side during spinning and stretching, and the internal strain differs between the two components. Therefore, the high-viscosity side is greatly shrunk due to the difference in elastic recovery rate after stretching and the heat shrinkage difference in the heat treatment process of the fabric, so that distortion occurs in the single fiber, and a three-dimensional coiled helical crimp is likely to appear. It can be said that the diameter of the helical crimp and the number of crimps of the single filament are determined by the contraction difference (including the elastic recovery rate difference) between the high contraction component and the low contraction component. The larger the contraction difference, the larger the diameter of the helical crimp. Is small, and the number of crimps of the single filament increases. As a stretch material, the coil crimp has a small diameter of the helical crimp, a large number of crimps of the single filament (that is, excellent stretch characteristics and good appearance), and the helical crimp has good sag resistance. (The amount of helical crimp sag according to the number of expansions and contractions is small and the stretch retainability is excellent). Furthermore, since the stretch property of the helical crimp is dominated by the stretch property of the high shrinkage component with the low shrinkage component as a fulcrum, the polymer used for the high shrinkage component preferably has high extensibility and recoverability, Polyethylene terephthalate may be disposed as a low shrinkage component, and polytrimethylene terephthalate as a high shrinkage component.

  In the present invention, the intrinsic viscosity of polytrimethylene terephthalate is preferably 1.0 or more from the viewpoint of obtaining coiled crimps and obtaining desired stretchability when a knitted fabric is formed. More preferably, it is 2 or more.

  In the present invention, the weight ratio of polyethylene terephthalate / polytrimethylene terephthalate in the polyester-based composite fiber is in the range of 30/70 or more and 70/30 or less from the viewpoint of yarn production and dimensional uniformity of the coil in the fiber length direction. . Preferably it is 35/65 or more and 65/35 or less, More preferably, it is the range of 40/60 or more and 60/40 or less.

Furthermore, in the present invention, the twist coefficient K of the coated elastic yarn is preferably in the range of 3000 to 10,000. The twist coefficient K is a value calculated by the following equation: K = T × D ^1/2
However, T: the number of twists (times / m), D: the total fineness (decitex) of the yarn.

  When the twisting coefficient K is less than 3000, problems occur in the covering properties of the coated elastic yarn, and in particular, a phenomenon occurs in which the polyurethane elastic yarn as the core yarn is exposed in a stretched state after being formed into a fabric. It becomes easy to do. On the other hand, when the twist coefficient is more than 10,000, the sheath yarn restrains the core yarn, and it becomes difficult to obtain desired extensibility.

  The coated elastic yarn of the present invention preferably has a structure in which the sheath yarn is coated single or double. When performing double coating, it is preferable to reverse the twist direction of the lower twist and the upper twist in consideration of the torque balance of the coated elastic yarn. Generally, the lower twist is the S direction and the upper twist is the Z direction. And

  Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to these examples.

  In addition, the intrinsic viscosity [η] in the examples, the stretch elongation rate (%), the number of crimps of single filament (mountain / 25 mm), the hot water shrinkage rate (%), the elongation recovery rate at 20% elongation (%) Was determined by the following method.

<Intrinsic viscosity [η]>
A sample of 0.10 g was dissolved in 10 ml of orthochlorophenol and measured using an Ostwald viscometer at a temperature of 25 ° C.

<Expansion / extension rate (%)>
Under a load of 1.8 × 10 ⁻³ cN / decitex, a 10-turn casserole was made with a hand-held measuring scale with a circumference of 1 m, and this was loaded with a load of 1.8 × 10 ⁻³ cN / decitex Then, hot water treatment is performed at 90 ° C. for 20 minutes. Next, the load is removed and air-dried for one day and night. The length of the sample under 1.8 × 10 ⁻³ cN / decitex load is measured (L0). Thereafter, a load of 88.3 × 10 ⁻³ cN / dtex is applied, and the length of the sample is measured after 2 minutes (L1). And the expansion / contraction elongation rate is calculated by the following formula. The number of tests was 20 and the average value was obtained.
Expansion / contraction elongation (%) = [(L1-L0) / L0] × 100
<Number of crimps of single filament (mountain / mm)>
A single yarn was taken out from the sampled crimped yarn, and the number of crimps between 25 mm was measured under a load of 1.8 × 10 ⁻³ cN / dtex. The average value of 20 single yarns was defined as the number of crimps of the single filament.

<Hot water shrinkage (%)>
JIS-L-1013 (1999) 8.18.1 Hot water shrinkage rate a) Measurement was performed according to the skein shrinkage rate (Method A).
<Elongation recovery rate at 20% elongation (%)>
Using a constant speed extension type tensile tester with a self-recording device, with an initial load of 0.08826 cN per decitex, it is mounted at 20 cm grip intervals, 20% elongation at a tensile speed of 20 cm / min. And immediately deweighted at the same speed. Immediately after complete dewetting, the film was stretched to the initial load, and the recovery elongation at this time was defined as the elongation recovery rate.

<Appearance and stretch evaluation of tights>
The appearance and texture of the finished tights were subjected to sensory evaluation by 5 female monitors in their 20s to 50s wearing them. The average score of the external appearance and stretchability evaluation score results is shown as each evaluation score. The total score of each evaluation score is regarded as comprehensive evaluation, and the larger the comprehensive evaluation, the better.

  Appearance evaluation point 3: The tights surface is flat and beautiful.

              2: Slight irregularities can be confirmed on the tights surface.

              1: Unevenness can be clearly seen on the tights surface.

  Stretchability evaluation point 3: Excellent stretchability.

                    2: Slightly lacking in stretchability.

1: The stretch property is lacking.
[Example 1]
Polytrimethylene terephthalate with an intrinsic viscosity of 1.31 and polyethylene terephthalate with an intrinsic viscosity of 0.52 were melted separately, and a weight ratio of polyethylene terephthalate / polytrimethylene terephthalate from a composite spinneret with 24 holes at a spinning temperature of 260 ° C. Was discharged at a spinning speed of 1400 m / min to obtain an undrawn yarn of 165 dtex 24 filaments. Further, using a hot roll-hot plate drawing machine, drawing is performed at a hot roll temperature of 70 ° C., a hot plate temperature of 145 ° C., and a draw ratio of 3.0, and a side-by-side type polyester composite fiber (drawn yarn) of 56 dtex 24 filaments. Got.
The obtained polyester-based conjugate fiber was run while being in contact with a hot plate, and subjected to tension heat treatment under the following conditions to obtain an actual crimped yarn. Table 1 shows the stretch elongation rate (%) of the actual crimped yarn obtained, the number of crimps (crest / mm) of the single filament, and the hot water shrinkage rate (%). (Tension heat treatment conditions)
Yarn processing speed: 300 m / min
Hot plate temperature: 130 ° C
Stretch ratio: 1.03
Covering was carried out under the following conditions using a polyurethane elastic fiber having a total fineness of 22 dtex as a core yarn and the obtained crimped yarn as a sheath yarn to obtain a single-coated elastic yarn. Table 2 shows the elongation recovery rate (%) and the twist coefficient at 20% elongation of the obtained coated elastic yarn.
[Covering conditions]
Draft: 2.9
Number of twists: 600 T / m
Using a four-sock sock knitting machine KT-C4 manufactured by Nagata Seiki, two S and Z twists of the obtained coated elastic yarn were used, respectively, placed on the leg part and the pant part to knit tights. The obtained fabric was dyed with a disperse dye for polyester as usual, finished, and a template was set to obtain tights. The evaluation results of the appearance and stretchability of the tights obtained are shown in Table 3.
[Example 2]
Polytrimethylene terephthalate with an intrinsic viscosity of 1.31 and polyethylene terephthalate with an intrinsic viscosity of 0.52 were melted separately, and a weight ratio of polyethylene terephthalate / polytrimethylene terephthalate from a 48-hole composite spinneret at a spinning temperature of 260 ° C. Was discharged at a spinning speed of 1400 m / min to obtain an undrawn yarn of 165 dtex 48 filaments. Further, using a hot roll-hot plate drawing machine, drawing is performed at a hot roll temperature of 70 ° C., a hot plate temperature of 145 ° C., and a draw ratio of 3.0, and a 56 dtex 48 filament side-by-side type polyester composite fiber (drawn yarn). Got.

  The polyester-based composite fiber obtained in the same manner as in Example 1 was run while being in contact with a hot plate, and subjected to tension heat treatment under the following conditions to obtain an actual crimped yarn. Table 1 shows the stretch elongation rate (%) of the actual crimped yarn obtained, the number of crimps (crest / mm) of the single filament, and the hot water shrinkage rate (%).

[Tension heat treatment conditions]
Yarn processing speed: 300 m / min
Hot plate temperature: 130 ° C
Stretch ratio: 1.03
Covering was carried out under the following conditions using a polyurethane elastic fiber having a total fineness of 22 dtex as a core yarn and the obtained crimped yarn as a sheath yarn to obtain a single-coated elastic yarn. Table 2 shows the elongation recovery rate (%) and the twist coefficient at 20% elongation of the obtained coated elastic yarn.
[Covering conditions]
Draft: 2.9
Number of twists: 600 T / m
Using a four-sock sock knitting machine KT-C4 manufactured by Nagata Seiki, two S and Z twists of the obtained coated elastic yarn were used, respectively, placed on the leg part and the pant part to knit tights. The obtained fabric was dyed with a disperse dye for polyester as usual, finished, and a template was set to obtain tights. The evaluation results of the appearance and stretchability of the tights obtained are shown in Table 3.
[Example 3]
The 56 dtex 24-filament side-by-side polyester composite fiber obtained in Example 1 was wound once on a hot pin and allowed to run, and subjected to tension heat treatment under the following conditions to obtain an actual crimped yarn. Table 1 shows the stretch elongation rate (%) of the actual crimped yarn obtained, the number of crimps (crest / mm) of the single filament, and the hot water shrinkage rate (%).

[Tension heat treatment conditions]
Yarn processing speed: 300 m / min
Hot pin temperature: 120 ° C
Stretch ratio: 1.03
Covering was carried out under the following conditions using polyurethane elastic fibers having a total fineness of 22 dtex as core yarns and the obtained crimped yarns as sheath yarns to obtain double-coated elastic yarns. Table 2 shows the elongation recovery rate (%) and the twist coefficient at 20% elongation of the obtained coated elastic yarn.
[Covering conditions]
Draft: 3.4
Number of lower twists: S800T / m
Number of upper twists: Z680 T / m
Using a four-piece sock knitting machine KT-C4 manufactured by Nagata Seiki, it was placed on the leg and pants using four of the coated elastic yarns obtained, and tights were knitted. The obtained fabric was dyed with a disperse dye for polyester as usual, finished, and a template was set to obtain tights. The evaluation results of the appearance and stretchability of the tights obtained are shown in Table 3.
[Comparative Example 1]
Polyethylene terephthalate having intrinsic viscosities of 0.78 and 0.47 are melted separately so that the weight ratio of polyethylene terephthalate / polytrimethylene terephthalate is 50/50 from a composite spinneret with 24 holes at a spinning temperature of 260 ° C. The yarn was discharged and taken up at a spinning speed of 1400 m / min to obtain an undrawn yarn of 165 dtex 24 filaments. Further, using a hot roll-hot plate drawing machine, the hot roll temperature is 70 ° C., the hot plate temperature is 145 ° C., and the draw ratio is 3.0, and the side-by-side type polyethylene terephthalate composite fiber (drawn yarn) of 56 dtex 24 filaments. Got.

  The polyester-based composite fiber obtained in the same manner as in Example 1 was run while being in contact with a hot plate, and subjected to tension heat treatment under the following conditions to obtain an actual crimped yarn. Table 1 shows the stretch elongation rate (%) of the actual crimped yarn obtained, the number of crimps (crest / mm) of the single filament, and the hot water shrinkage rate (%).

[Tension heat treatment conditions]
Yarn processing speed: 300 m / min
Hot plate temperature: 130 ° C
Stretch ratio: 1.03
Covering was carried out under the following conditions using a polyurethane elastic fiber having a total fineness of 22 dtex as a core yarn and the obtained crimped yarn as a sheath yarn to obtain a single-coated elastic yarn. Table 2 shows the elongation recovery rate (%) and the twist coefficient at 20% elongation of the obtained coated elastic yarn.
[Covering conditions]
Draft: 2.9
Number of twists: 600 T / m
Using a four-sock sock knitting machine KT-C4 manufactured by Nagata Seiki, two S and Z twists of the obtained coated elastic yarn were used, respectively, placed on the leg part and the pant part to knit tights. The obtained fabric was dyed with a disperse dye for polyester as usual, finished, and a template was set to obtain tights.

The evaluation results of the appearance and stretchability of the tights obtained are shown in Table 3.
[Comparative Example 2]
The side-by-side type polyester composite fiber of 56 dtex 24 filaments obtained in Example 1 was not subjected to tension heat treatment and used as a latent crimped yarn. Table 1 shows the stretch elongation rate (%) of the polyester composite fiber (latent crimped yarn), the number of crimps (crest / mm) of the single filament, and the hot water shrinkage rate (%).

Using a polyurethane elastic fiber having a total fineness of 22 dtex as a core yarn and a polyester composite fiber (latent crimped yarn) as a sheath yarn, covering was performed under the following conditions to obtain a single-coated elastic yarn. Table 2 shows the elongation recovery rate (%) and the twist coefficient at 20% elongation of the obtained coated elastic yarn.
[Covering conditions]
Draft: 2.9
Number of twists: 600 T / m
Using a four-sock sock knitting machine KT-C4 manufactured by Nagata Seiki, two S and Z twists of the obtained coated elastic yarn were used, respectively, placed on the leg part and the pant part to knit tights. The obtained fabric was dyed with a disperse dye for polyester as usual, finished, and a template was set to obtain tights.

  The evaluation results of the appearance and stretchability of the tights obtained are shown in Table 3.

  When the coated elastic yarn of the present invention is used for clothes and the like, a fabric having a flat surface feeling and excellent stretchability can be obtained. For clothing, in particular, stretch materials such as inner and stockings can be provided, but the application range is not limited thereto.

It is a schematic side view which shows an example of the covering elastic yarn of this invention.

Explanation of symbols

(B): Covered elastic yarn (b): Polyurethane elastic yarn (c): Realized crimped yarn (d): Helical crimp

Claims (5)

A covered elastic yarn composed of a core yarn and a sheath yarn, using polyurethane-based elastic fibers as the core yarn, and one of the constituent components of the sheath yarn is composed mainly of polyethylene terephthalate and the other is composed mainly of polytrimethylene terephthalate. A coated elastic yarn comprising a polyester-based composite fiber that is a side-by-side type or an eccentric core-sheath type and that uses an actual crimped yarn that satisfies the following (1) to (3).
-Stretch rate is 100% or more-Single filament has 25 crimps / 25mm or more-Hot water shrinkage rate is 10% or less 2. The coated elastic yarn according to claim 1, wherein an elongation recovery rate at 20% elongation is 80% or more. The intrinsic viscosity of the constituent components of the polyester-based composite fiber is different, and the intrinsic viscosity ratio ([ηb] / [ηa]) between the intrinsic viscosity [ηb] of the low-viscosity polyester and the intrinsic viscosity [ηa] of the high-viscosity side The coated elastic yarn according to claim 1 or 2, wherein is from 0.3 to 0.8. The composite ratio (weight ratio) of the constituent components in the polyester-based composite fiber is in the range of polyethylene terephthalate / polytrimethylene terephthalate = 30/70 to 70/30. Coated elastic yarn. The coated elastic yarn according to any one of claims 1 to 4, wherein a twist coefficient is in a range of 3000 to 10,000.
However, twist coefficient K = T × D ^1/2
T: Number of twists (times / m), D: Total fineness (decitex) of yarn.

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