JP2003221744A - Core spun yarn and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a core spun yarn capable of affording a thin stretchable fabric having excellent burning, heat and wound resistances and a flat appearance and a method for producing the core spun yarn. <P>SOLUTION: This core spun yarn comprises a core yarn and a sheath yarn and is obtained by using polyester conjugated fibers of the side-by-side type or the eccentric sheath-core type comprising one of constituent components consisting essentially of polyethylene terephthalate and other constituent component consisting essentially of polytrimethylene terephthalate as the core yarn and aramid fibers as the sheath yarn. The method for producing the core spun yarn is provided. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a core spun yarn and a method for producing the same.

More specifically, the core-spun yarn of the present invention is used for higher-order processing and used for clothes and the like,
The present invention relates to a core-spun yarn that is excellent in combustion resistance, heat resistance, and cut resistance, and that can obtain a stretch fabric having a thin and flat appearance and a manufacturing method thereof.

[0003]

2. Description of the Related Art General-purpose thermoplastic synthetic fibers such as nylon and polyester fibers, which are widely used as clothing and industrial materials, melt at about 250 ° C. and have a limiting oxygen index of about 2
It is around 0 and burns well in the air. Therefore, these general-purpose thermoplastic synthetic fibers are used for clothing products used in situations where there is a high risk of exposure to flames and high heat, such as fire fighting clothing, racing suits for automobile races, workwear for steelmaking, workwear for welding and gloves. It cannot be said that it is suitable as a fiber material for protection such as.

Aramid fibers do not melt at around 250 ° C, and their decomposition temperature is high at around 500 ° C. Further, the limiting oxygen index is about 25 or more, and in the air, combustion is performed by bringing a flame, which is a heat source, close to it, but if the flame is moved away, the combustion cannot be continued.

As described above, the aramid fiber is a material excellent in heat resistance and flame retardancy. Therefore, for example, aramid fiber is used in clothing products in situations where there is a high risk of exposure to flames and high heat, such as fire fighting clothing, racing suits for automobile racing, iron workwear, welding workwear, and protective clothing such as gloves. Used favorably. Among them, the para-aramid fiber, which has both high heat resistance and high strength characteristics, is used for sports clothing, work clothes, ropes, tire cords, etc. that require tear strength and heat resistance, and because it is difficult to cut with a blade, it is a wound. It is also used as work gloves for prevention.

As the para-aramid fiber, polyparaphenylene terephthalamide fiber (hereinafter referred to as PPTA fiber) is well known, for example, US Pat. No. 3,767,75.
No. 6 specification, Japanese Patent Publication No. 56-128, 312, PP
A method of making TA fibers is disclosed.

On the other hand, the meta-aramid fiber is used for fire fighting clothes, heat insulating filters, heat resistant dust collecting filters, electric insulating materials and the like.

Heretofore, when these aramid fibers were used to manufacture textile products such as clothing products, these fibers were merely used in the form of filament yarns or spun yarns having no elasticity.

However, even if a non-stretchable yarn such as a filament yarn or a spun yarn is processed into a fabric to manufacture a clothing product such as a fire fighting suit, a racing suit or work clothes, the clothing product is inferior in stretchability. Therefore, there is a problem that it is uncomfortable to wear and it is difficult to carry out activities.

Similarly, the conventional work gloves made of non-stretchable yarns have a bad wearing feeling and have been a cause of lowering work efficiency.

In view of the demands of the market, many researches and proposals have been made on a method for providing a heat-resistant crimped yarn or a heat-resistant and high-performance fiber with crimps (JP-A-48-1981).
No. 8, JP-A-53-114923, and JP-A-3
No. 27117). Specifically, a method in which a general thermoplastic synthetic fiber crimping method such as nylon fiber or polyester fiber is applied can be used. For example, a method in which high elastic modulus fibers such as para-aramid fibers are mixed with low elastic modulus fibers and crimp is applied by an indentation method (Japanese Patent Laid-Open No. 1-1.
No. 92839), the aramid fiber is decomposed at a temperature above its decomposition temperature and below its decomposition temperature (390 in the case of meta-aramid fiber).
The crimped yarn (Japanese Patent Laid-Open No. 6-280120) produced by a false twisting method, in which a false twist crimping process is performed using a non-contact heater heated to a temperature of 1800 ° C. or higher but lower than 460 ° C., and a relaxation heat treatment is disclosed. ing.

However, by any of the conventional methods,
It was not possible to obtain a heat-resistant high-performance fiber having good stretchability.

[0013]

SUMMARY OF THE INVENTION It is an object of the present invention to solve the problems of the prior art and to provide a core spun yarn having good stretchability and a method for producing the same.

That is, the present invention (a) is excellent in stretchability, heat resistance, mechanical strength and appearance, and (b) when it is formed into a textile product such as a knitted fabric and gloves, it fits well on the body such as hands. An object is to provide a core-spun yarn having good workability and a method for producing the same.

[0015]

The corespun yarn of the present invention adopts the following means in order to solve the above-mentioned problems.

That is, a core-spun yarn composed of a core yarn and a sheath yarn, wherein one of the constituent components of the core yarn is polyethylene terephthalate as a main component and the other constituent component is a polytrimethylene terephthalate as a main component. An eccentric sheath / core type polyester-based composite fiber is used, and an aramid fiber is used for a sheath yarn, which is a core-spun yarn.

The corespun yarn manufacturing method of the present invention employs the following means in order to solve the above problems.

That is, a side-by-side type or eccentric sheath / core type polyester-based composite fiber in which one of the constituents contains polyethylene terephthalate as the main component and the other constituent contains polytrimethylene terephthalate as the main constituent is used as the core yarn. A method for producing a core spun yarn, characterized in that aramid fiber is used as a sheath yarn.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION The core spun yarn of the present invention will be described below. FIG. 1 is a schematic side view showing an example of the core spun yarn of the present invention. The core spun yarn (C) of the present invention is
A core-spun yarn having a core-sheath structure in which the polyester-based composite fiber (a) having an actual crimp as a core yarn is covered with an aramid fiber (b) as a sheath yarn while being twisted. Figure 2
FIG. 3 is a schematic side view of the core-spun yarn (he) of the present invention that has been treated with boiling water at 98 ° C. for 30 minutes under no load. By the boiling water treatment, the polyester-based conjugate fiber (d) develops a latent crimp while highly shrinking, so that the core-spun yarn of the present invention generates an appropriate yarn length difference and crimp, and has a high bulkiness. It will be highly stretchable.

The core yarn of the core-spun yarn of the present invention is a side-by-side type or an eccentric sheath / core type in which one of the constituent components contains polyethylene terephthalate as a main component and the other constituent component contains polytrimethylene terephthalate as a main component. A polyester-based composite fiber is used.

When the polymers having different intrinsic viscosities are bonded to each other in the polyester-based conjugate fiber, stress concentrates on the high viscosity side during spinning and drawing, so that the internal strain differs between the two components. Therefore, the high-viscosity side is largely shrunk due to the difference in elastic recovery rate after stretching and the difference in heat shrinkage in the heat treatment step of the cloth, and distortion occurs in the single fiber to take a three-dimensional coil crimp form. It can be said that the diameter of the three-dimensional coil and the number of coils per single fiber length are determined by the shrinkage difference (including the elastic recovery rate difference) between the high shrinkage component and the low shrinkage component. Is small, and the number of coils per unit fiber length is large.

The coil crimp required as a stretch material has a small coil diameter, a large number of coils per unit fiber length (excellent elongation characteristics and good appearance), and good coil settling resistance (expansion and contraction). The amount of coil fatigue depending on the number of times is small and the stretch retention property is excellent. Furthermore, the expansion and contraction characteristics of the coil are dominated by the expansion and contraction characteristics of the high contraction component with the low contraction component as the fulcrum. The polymer used for is required to have high extensibility and recoverability. Therefore, the inventors of the present invention have conducted extensive studies in order to satisfy the above properties without impairing the properties of polyester. As a result, the low shrinkage component contains polyethylene terephthalate as a main component, and the high shrinkage component contains polytrimethylene terephthalate as a main component. It was found to use the polyester composite fiber. The polytrimethylene terephthalate fiber has mechanical properties and chemical properties equivalent to those of polyethylene terephthalate fiber and polybutylene terephthalate fiber, which are typical polyester fibers, and is extremely excellent in elongation recovery. This is because the methylene chain of the alkylene glycol part in the crystal structure of polytrimethylene terephthalate is gauche-
The gauche structure (the molecular chain bends at 90 degrees), the density of constraint points due to the interaction between the benzene rings (stacking, parallel) is low, and the flexibility is high. We believe that it will easily grow and recover.

The polyethylene terephthalate, which is a constituent component of the core yarn in the core spun yarn of the present invention, is preferably a polymer component having an ethylene terephthalate unit as a main repeating unit. That is, as the polyethylene terephthalate in the present invention, a polyester obtained by using terephthalic acid as a main acid component and ethylene glycol as a main glycol component is preferable.
However, other copolymerizable components capable of forming an ester bond are 2
Those contained in a proportion of 0 mol% or less are preferable, and those contained in a proportion of 10 mol% or less are more preferable. As the copolymerizable compound, for example, sulfonic acid, sodium sulfonic acid, sulfuric acid, sulfuric ester, diethyl sulfate,
Dicarboxylic acids such as ethyl sulfate, aliphatic sulfonic acid, ethanesulfonic acid, chlorobenzenesulfonic acid, alicyclic sulfonic acid, isophthalic acid, sebacic acid, azelaic acid, dimer acid, adipic acid, oxalic acid and decanedicarboxylic acid, p- Dicarboxylic suns such as hydroxybenzoic acid and hydroxycarboxylic acids such as ε-caprolactone, diols such as triethylene glycol, polyethylene glycol, propanediol, butanediol, pentanediol, hydroquinone and bisphenol A are preferably used.

If desired, titanium dioxide as a matting agent, fine particles of silica or alumina as a lubricant, hindered phenol derivatives as antioxidants, color pigments, etc. may be added.

Polytrimethylene terephthalate, which is another constituent of the core yarn in the core spun yarn of the present invention, is
Those comprising a polymer component containing a trimethylene terephthalate unit as a main repeating unit are preferable.

That is, as the polytrimethylene terephthalate in the present invention, a polyester obtained by using terephthalic acid as a main acid component and 1,3 propanediol as a main glycol component is preferable. However, it is also preferable that the content of the other copolymerizable component capable of forming an ester bond is 20 mol% or less, and that of 10 mol% or less is more preferable. Examples of the copolymerizable compound include diphthalic acids such as isophthalic acid, succinic acid, cyclohexanedicarboxylic acid, adipic acid, dimer acid, sebacic acid and 5-sodium sulfoisophthalic acid, ethylene glycol, diethylene glycol,
Diols such as butanediol, neopentyl glycol, cyclohexanedimethanol, polyethylene glycol and polypropylene glycol are preferably used.

If desired, titanium dioxide as a matting agent, fine particles of silica or alumina as a lubricant, hindered phenol derivatives as antioxidants, color pigments and the like may be added.

In the present invention, the intrinsic viscosity of polytrimethylene terephthalate is 1. From the viewpoint of expressing a coiled crimp and obtaining desired stretchability when forming a knitted fabric.
It is preferably 0 or more, more preferably 1.2 or more.

The cross-sectional shape of the single fiber of the polyester composite fiber used in the present invention is a side-by-side type or an eccentric sheath / core type.

Unless the cross-sectional shape is a side-by-side type or an eccentric sheath / core type, when heat is applied to the yarn,
There is a problem that the coiled crimp does not appear and the yarn cannot be stretched.

The weight ratio of polyethylene terephthalate / polytrimethylene terephthalate in the polyester composite fiber is in the range of 30/70 or more and 70/30 or less from the viewpoint of spinnability and dimensional homogeneity of the coil in the fiber length direction. It is preferable.

The fineness of the polyester-based conjugate fiber is preferably in the range of 20 decitex or more and 1000 decitex or less depending on the purpose of use.

Further, the single yarn fineness of the polyester composite fiber is preferably in the range of 0.4 decitex or more and 25 decitex or less depending on the application.

It is indispensable to use aramid fiber as the sheath yarn of the core spun yarn of the present invention. If the aramid fiber is not used for the sheath yarn, there is a problem that it is not possible to obtain sufficient flame resistance, heat resistance, and tear strength when used for material applications such as knitted fabrics or ropes.

The aramid fibers used as the sheath yarn include meta-aramid fibers and para-aramid fibers, and the meta-aramid fibers are preferable from the viewpoint of having high strength properties.

Examples of the meta-aramid fibers include meta-aromatic polyamide fibers such as polymetaphenylene isophthalamide fiber (trade name "Nomex" manufactured by DuPont). Examples of the para-aramid fiber include polyparaphenylene terephthalamide fiber (trade name “Kevlar” manufactured by DuPont Toray Co., Ltd.) and copolyparaphenylene-3,4′-diphenyl ether terephthalamide fiber (trademark manufactured by Teijin Limited. Para-type wholly aromatic polyamide fibers such as the name "Technora").

The aramid fiber used as the sheath yarn is a short fiber bundle, a roving yarn or a spun yarn, which may be spun alone or mixed.

The fineness of the aramid fiber depends on the purpose of use.
It may be appropriately selected in consideration of surface appearance, combustion resistance, heat resistance, stretchability, texture, and the like.

The fineness of the sheath roving is 80 depending on the purpose of use.
The range of 0 decitex or more and 40,000 decitex or less is preferable, and the fineness of the sheath yarn after drafting is preferably 20 decitex or more and 1000 decitex or less.

The core-spun yarn in the present invention is a processed yarn in which the core yarn is a filament and the sheath yarn is a short fiber bundle, a roving yarn, or a spun yarn. For example, during the spinning process, the roving yarn is drafted on the core yarn. It is obtained by winding while winding.

Next, the method for producing the core spun yarn of the present invention will be described with reference to FIG.

FIG. 3 is a schematic diagram showing an example of producing the core spun yarn of the present invention using a commercially available spinning machine.

In the present invention, a polyester composite fiber and an aramid fiber are used. In this example, the polyester-based composite fibers are filament yarns, and the aramid fibers are spun yarn rovings.

In FIG. 3, the polyester-based conjugate fiber used as the core yarn 1 has a coil-shaped actual crimp, and is subjected to fine spinning by twisting the actual crimp in a stretched state, From the viewpoint of improving the coverage of the core spun yarn, a draft of 1.02 to 1.70 times may be applied between the feed roller 4 and the delivery roller 7 before the aramid fiber that is the sheath yarn 2 and the delivery roller 7 are aligned. preferable.

Alternatively, it is preferable to apply a tension of 0.01 cN / dtex or more.

As a method of applying tension, it is preferable to insert a washer tensor, a magnet tensor or the like. In FIG. 3, the washer tensor 3 is used.

On the other hand, the sheath yarn 2, which is a aramid fiber roving, is 25 to 50 before being aligned with the core yarn 1 by the delivery roller 7.
It is preferable to double the draft. The yarns aligned on the delivery roller 7 are twisted by rotating the spindle, and wound on the winding package 9 via the snell guide 8.

The number of twists in the fine spinning twist is such that after the fabric is formed and heat-treated, the covering property is sufficient to prevent the occurrence of the eye direction and to prevent the feeling of stickiness. From the viewpoint of preventing the core yarn from being restrained by the sheath yarn and greatly reducing the stretchability of the fabric and preventing the texture from becoming hard, it may be appropriately selected depending on the fineness of the sheath yarn and the number of filaments. It is preferably in the range of 100 to 2000 T / m.

The knitted fabric using the core spun yarn of the present invention is excellent in flame resistance, heat resistance and tear strength, has a flat appearance,
It has a soft texture and is excellent in stretchability and morphological stability, especially in fire fighting clothes, racing suits for automobile races, work clothes for steelmaking or work clothes for welding, sports clothing and work clothes, and other clothing products. It can be used for materials such as ropes, tire cords, etc.

[0050]

The present invention will be described in more detail with reference to the following examples.

The intrinsic viscosity (η) in the examples was determined by the following method. However, the present invention is not limited to these examples. [Intrinsic Viscosity (η)] 0.10 g of a sample was dissolved in 10 ml of orthochlorophenol and measured at a temperature of 25 ° C using an Ostwald viscometer. [Tensile strength] Using a constant-speed extension type tensile tester with a self-recording device, attached at a gripping interval of 10 cm with an initial load of 7 mg per decitex, and a tensile speed of 20 cm
/ Minute, the sheet was stretched until it was broken, and the strength at the time of breaking was measured. [Elongation and Residual Strain at 5cN Load] Using a constant-speed extension type tensile tester with a self-recording device, the initial load of 7 mg per decitex was applied at a gripping interval of 10 cm, and the pulling speed was 20 cm / As a minute, the sample was stretched to a load of 5 cN and the elongation under a load of 5 cN was measured. 5
Immediately after the loading of cN, the load was removed at the same speed, and the elongation at the time of complete removal was taken as the residual strain. [Stretchability] JIS L 1013: 1999 Chemical fiber filament yarn test method 8.11. Stretching elongation was measured by method A. As a pretreatment before the measurement, the measurement sample was skein-shaped and wrapped in gauze, followed by hot water treatment at 90 ° C. for 20 minutes, and naturally dried at room temperature. [Fineness] The fineness was measured according to JIS L 1013: 1999 Chemical Fiber Filament Yarn Test Method 8.3. [Limiting oxygen index] JIS K 7201: 1999 Measured by a combustion test method for polymer materials according to the oxygen index method. [Heat resistance] The heat melting property was measured and used as an index showing heat resistance.

Thermal melting property: When a 6 cm × 6 cm sample was brought into contact with the tip of a metal rod (diameter: 0.6 cm) heated to 500 ° C. horizontally for 5 seconds under its own weight, a cloth was formed by heat. The degree of perforation was compared with the cross-sectional area of the metal rod and judged by grade. Grade 5; No hole, Grade 4, 1/4 hole, Grade 3, 1/2 hole, Grade 2, 3/4 hole, Grade 1;
Completely perforated. [Combustion test] In accordance with JIS L 1091-1999 Flammability test method for textile products, according to 8.1.1A-1 method (45 micro burner method), the perforated area after heating for 1 minute with a specified burner was measured. [Cut resistance] ISO 1
3997: 1999 (Protective clothing-Mechanic
al properties-Determination of resistance to cut
ting by sharp objects). According to the principle of this measuring method, when a blade penetrates (cuts) a test piece at a constant moving distance, a heavier load is required for a material that is more difficult to cut. With the load L applied to the blade, when the blade penetrates the test piece at a moving distance of 20 mm, the load L is taken as the cut resistance value. Blade
American Safety Razor Co., product number No. 88-0121 was used. The measured value is represented by N (= Newton), and the larger the value, the more difficult it is to cut.

[Example 1] Polytrimethylene terephthalate having an intrinsic viscosity of 1.31 and polyethylene terephthalate having an intrinsic viscosity of 0.52 were separately melted and spun at a spinning temperature of 260 ° C through a 24-hole composite spinneret. / Polytrimethylene terephthalate is discharged at a weight ratio of 50/50, and the spinning speed is 14
It was taken up at 00 m / min to obtain an undrawn yarn of 500 dtex34 filament. Further, using a hot roll-hot plate stretching machine, hot roll temperature 70 ° C., hot plate temperature 145
Stretching was performed at a draw ratio of 3.0 ° C. to obtain a 168 dtex34 filament side-by-side type polyester-based composite fiber (drawn yarn). Using the obtained polyester-based composite fiber as a core yarn, PPTA fiber manufactured by Toray DuPont Co., Ltd. (trade name "Kevlar" (R), limiting oxygen index 28, thermal decomposition point 5
(37 ° C.) Using a roving as a sheath yarn, fine spinning twisting was performed under the following conditions using the fine spinning process shown in FIG. In addition,
The polyester-based composite fiber is a partner material, PPT.
The yarn was fed and pre-drafted via a washer tensor so that a pre-tension of 0.01 cN / dtex or more was applied before being aligned with the A roving yarn.

Pre-tension on polyester-based composite fiber side: 4 g Draft on polyester-based composite fiber side: 1.1 Draft on PPTA roving side: 40 Twist number: Z300 T / m The obtained core-spun yarn was 98 in an unweighted state. Those that have been subjected to boiling water treatment at 30 ° C for 30 minutes to develop crimp have a tensile strength of 10.3 cN / dtex and a limiting oxygen index of 26,5 cN.
It had an elongation under load of 4.0% and a residual strain of 1.9%, had good crimps, excellent combustion resistance, high strength and high elasticity. The obtained corespun yarn was knitted using a 20-gauge single-pitch knitting machine, scoured and finished, and was highly stretchable. The number of limit acid elements was 26, the heat melting property was grade 5, and the hole was obtained by a combustion test. The open area was 0 cm ² . The cut resistance of this knitted fabric was 1.2 N.
Thus, a knitted fabric having excellent combustion resistance, heat resistance, cut resistance, soft texture, thin fabric, and flat appearance was obtained.

[Example 2] The same side-by-side type polyester conjugate fiber of 168 dtex34 filament as that used in Example 1 was used as the core yarn and PP as the sheath yarn.
Using TA roving, fine spinning and twisting was performed under the following conditions in the same manner as in Example 1 to obtain a core spun yarn.

Pre-tension on polyester composite fiber side: 4 g Draft on polyester composite fiber side: 1.1 Draft on PPTA roving yarn side: 40 Twist number: Z550 T / m 0c
It was m ² . The cut resistance of this fabric is 1.3N.
Met. Thus, a knitted fabric having excellent flammability resistance, heat resistance, cut resistance, soft texture, thin fabric, and flat appearance was obtained.

[Comparative Example 1] Using 33 dtex polyurethane yarn and PPTA roving, fine spinning was conducted under the following conditions in the same manner as in Example 1 to obtain a core spun yarn. However, the polyurethane yarn is fed by rolling (positive feed), and only the polyurethane yarn is stretched 3.7 times in advance between the yarn feeding roller and the delivery roller, and then it is aligned with the PPTA fiber and finely spun. did.

Draft on polyurethane yarn side: 40 Twist number: Z300T / m The obtained corespun yarn was treated with boiling water at 98 ° C. for 30 minutes in an unloaded state, and had a tensile strength of 10.6 cN / dt.
ex, limiting oxygen index is 26, elongation at 5 cN load is 4.
8%, residual strain 1.6%, excellent in flame resistance,
It had high strength and high elasticity. When the obtained core-spun yarn was knitted using a 20-gauge single-knitting machine, it was highly stretchable, had a limiting number of acid elements of 26, and had a heat melting property of grade 5,
The perforated area by the combustion test was 0 cm ² . Also,
The cut resistance of this knitted fabric was 1.2 N. Flame resistance,
Although it had excellent heat resistance, a thick knit fabric with a thick texture was obtained.

Comparative Example 2 The same side-by-side type polyester conjugate fiber of 168 dtex34 filament as that used in Example 1 was used as the core yarn, and polyethylene terephthalate roving was used as the sheath yarn under the same conditions as in Example 1 under the following conditions. Fine spinning twist was applied.

Pre-tension on polyester-based composite fiber side: 4 g Draft on polyester-based composite fiber side: 1.1 Draft on polyethylene terephthalate roving side: 40 Twist number: Z300 T / m The obtained corespun yarn has a tensile strength of 4 .4 cN / dt
ex, the limiting oxygen index is 20, and the elongation at a load of 5 cN is 5.
It had 3% and residual strain of 1.5%, had good crimps, and had high elasticity, but had a limiting acid element number of 20, lacked in combustion resistance, and had insufficient strength. When the obtained corespun yarn was knitted using a 20-gauge single-pitch knitting machine, although it had excellent stretch-back properties, it had a limit acid element number of 20, thermal melting property of 1st class, and was punched by a combustion test. The area was 45 cm ² or more, which was insufficient in heat resistance and combustion resistance. The cut resistance of this knitted fabric was 0.5 N, which was about 50% of that of the knitted fabric of Example 1.

[0061]

EFFECT OF THE INVENTION By using the core spun yarn of the present invention, it is possible to obtain a stretch cloth having excellent flammability, heat resistance and cut resistance and having a thin and flat appearance.

[Brief description of drawings]

FIG. 1 is a schematic side view showing an example of a core spun yarn of the present invention.

FIG. 2 is a schematic side view showing an example of the core-spun yarn of the present invention that has been subjected to boiling water treatment under a no-load condition.

FIG. 3 is a schematic diagram showing an example of a method for producing a core spun yarn of the present invention.

[Explanation of symbols]

(A): Polyester composite fiber (B): Aramid fiber (C): Core spun yarn (D): Polyester composite fiber (E): Aramid fiber (F): Core spun yarn 1: Core thread 2: sheath yarn 3: Washer tensor 4: Feed roller 5: Feed roller 6: Guide 7: Delivery roller 8: Snell guide 9: Winding package

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Hironori Uranaka             1-2-2 Sonoyama, Otsu City, Shiga Prefecture             DuPont Co., Ltd. Shiga Plant F-term (reference) 4L036 MA04 MA15 MA33 MA39 PA12                       PA31 PA45 RA25 UA06 UA25

Claims (5)

[Claims] 1. A core-spun yarn comprising a core yarn and a sheath yarn, wherein one of the constituent components of the core yarn is polyethylene terephthalate as a main component, and the other constituent component is of polytrimethylene terephthalate as a main component. An eccentric sheath / core type polyester-based composite fiber is used, and a aramid fiber is used for the sheath yarn, which is a core-spun yarn. 2. The core-spun yarn according to claim 1, wherein the weight ratio of polyethylene terephthalate / polytrimethylene terephthalate of the polyester-based conjugate fiber is 30/70 to 70/30. 3. The core-spun yarn according to claim 1, wherein the aramid fiber is a para-aramid fiber. 4. The core-spun yarn according to claim 1, wherein the aramid fiber is a polyparaphenylene terephthalamide fiber. 5. A side-by-side type or eccentric sheath / core type polyester-based composite fiber, one of the constituents of which has polyethylene terephthalate as a main component and the other of which has polytrimethylene terephthalate as a main component, as a core yarn. A method for producing a core-spun yarn, which comprises using aramid fiber as a sheath yarn.