JP7655522B2 - Double-layered spun yarn and woven/knitted fabrics - Google Patents

Description

The present invention relates to a novel two-layer structure spun yarn and a woven or knitted fabric obtained from the spun yarn.

In recent years, as development towards the SDGs (Sustainable Development Goals) progresses, the development of applications for natural fibers has been attracting attention as a sustainable textile material that leads to the reduction of carbon dioxide emissions. In addition to cotton and hemp, which have been used for a wide range of purposes, attempts have been made to use various fibers such as banana fiber and pineapple fiber, and kapok fiber is one such natural fiber.

Kapok is a deciduous tall tree belonging to the Malvaceae family that grows widely throughout the world, from Central America, the Caribbean Islands, northern South America, and the tropical West Africa to India and Southeast Asia. It is widely cultivated, mainly in Southeast Asia, for the fiber (fluff) extracted from its fruit.

More specifically, kapok fiber is a seed hair that grows on the inner surface of the fruit of the kapok tree, and is a fiber with an average fiber length of about 15 mm, mainly composed of cellulose. The morphological characteristics of kapok fiber are that it has a hollow structure (hollow ratio of about 70 to 80%) and the fiber surface is smooth and is covered with a certain type of wax.

It is known that spinning kapok fiber is difficult when used for textile applications. In other words, kapok fiber is difficult to spin because it is relatively short in length, does not crimp, and is a very light fiber that easily scatters during spinning. Even if a spun yarn containing kapok fiber is obtained, scattering of the kapok fiber due to friction during weaving or knitting is likely to be a problem.

As a method for solving the above problems, it is known to make a spun yarn by mixing kapok fiber with other fibers to suppress scattering of kapok fiber. For example, a spun yarn in which kapok fiber is unevenly distributed in the outer layer of a yarn has been proposed by selecting the raw cotton varieties or ratios of kapok fiber and other fibers and spun into a yarn by an open-end spinning machine (Patent Document 1). This method discloses that a spun yarn with less yarn breakage can be obtained by blending with other fibers, and that a spun yarn with kapok fiber unevenly distributed in the outer layer of a yarn can be obtained that has both sweat absorption and water repellency, and is bulky and has excellent heat retention.

In addition, a method has been proposed in which kapok fibers whose moisture content and length have been adjusted are blended with other fibers to produce spun yarn (Patent Document 2).

However, in spun yarns in which kapok fibers are simply blended with other fibers, or in spun yarns in which kapok fibers are unevenly distributed in the outer layer of the yarn as in Patent Document 1, the kapok fibers are present on the surface of the yarn, and therefore there is a problem that the kapok fibers fly off or fall off due to friction during weaving or knitting, making it difficult to maintain the fabric quality of the resulting woven or knitted fabric.

For example, in the spinning method of Patent Document 1, in order to prevent the kapok fibers from scattering, a method is adopted in which the kapok fibers are mixed with other fibers and then sliverized in a carding process, but the same problems as those described above occur.

Furthermore, if the strength of the spun yarn is insufficient, thread breakage or slippage occurs during weaving and knitting, resulting in a deterioration in fabric quality, and therefore a solution to the strength problem is desired for spun yarns using kapok fiber. Incidentally, slippage refers to the phenomenon in which, when a spun yarn is pulled with no twist or with a small amount of twist, the fibers in the spun yarn do not break but rather slip out, causing the yarn to break.

Japanese Patent Publication No. 55-36372 Special table 2022-510173

Therefore, the main object of the present invention is to solve the above-mentioned problems and to provide a kapok fiber-containing spun yarn which has practical strength, is less likely to scatter or fall off kapok fibers due to abrasion, particularly during weaving or knitting, and can be woven and knitted with good operability, while taking advantage of the characteristics of kapok fiber, such as light weight and bulkiness.

As a result of extensive research in light of the problems in the prior art, the inventors discovered that the above-mentioned object can be achieved by adopting a two-layer spun yarn having a core derived from a core sliver and a sheath derived from a sheath sliver, and thus completed the present invention.

That is, the present invention relates to the following two-layer spun yarn and woven/knitted fabric.
1. A spun yarn having a core derived from a core sliver and a sheath derived from a sheath sliver,
(1) In a cross section perpendicular to the longitudinal direction of the spun yarn, a core portion is disposed at the center of the cross section, and a sheath portion is disposed around the core portion,
(2) At least one of the core and the sheath contains kapok fiber;
(3) The content of kapok fiber in the spun yarn is 20 to 60% by mass.
A two-layer spun yarn characterized by:
2. The two-layer spun yarn according to item 1, wherein the core sliver contains kapok fiber, and the content of the kapok fiber in the spun yarn is 20 to 55 mass %.
3. The two-layer spun yarn according to claim 2, wherein the core sliver further contains at least one of a) chemical fibers and b) natural fibers other than kapok fibers.
4. The two-layer spun yarn according to claim 2, wherein the sheath sliver contains at least one of a) chemical fibers and b) natural fibers other than kapok fibers.
5. The two-layer spun yarn according to item 2, having a Worcester unevenness (U%) of 25.0% or less and a British cotton count of 5 to 60.
6. The following characteristics:
(a) Average strength: 120 cN or more,
(b) Strong fluctuation rate: 5-15%;
3. The two-layer spun yarn according to item 2, which satisfies both of (c) elongation: 4 to 20% and (d) twist coefficient K: 3.8 or more.
7. A woven or knitted fabric comprising the two-layer structure spun yarn according to item 2.
8. The two-layer spun yarn according to item 1, wherein the sheath sliver contains kapok fiber, and the content of the kapok fiber in the spun yarn is 20 to 60 mass %.
9. The two-layer spun yarn according to item 8, wherein the sheath sliver further contains at least one of a) chemical fibers and b) natural fibers other than kapok fibers.
10. The two-layer spun yarn according to item 8, wherein the core sliver contains at least one of a) chemical fibers and b) natural fibers other than kapok fibers.
11. The two-layer spun yarn according to item 10, wherein the chemical fibers have a fiber length of 20 to 50 mm.
12. The two-layer spun yarn according to item 10, wherein the chemical fiber has a hollow portion in the fiber cross-sectional shape.
13. The two-layer spun yarn according to item 8, having a Worcester unevenness (U%) of 25.0% or less and a British cotton count of 5 to 60.
14. The following characteristics:
(a) Average strength: 120 cN or more,
(b) Strong fluctuation rate: 4-20%;
The two-layer spun yarn according to claim 8, which satisfies both of (c) elongation: 4 to 20% and (d) twist coefficient K: 3.8 or more.
15. A woven or knitted fabric comprising the two-layer spun yarn according to item 8.
16. A method for producing a two-layer structure spun yarn, comprising the following steps (1) to (5):
(1) A process of producing a sheet-shaped wrap by a mixed-fibering process using a raw material containing kapok fiber and an oil agent, and obtaining a card sliver A1 from the wrap. (2) A process of producing a sheet-shaped wrap by a mixed-fibering process using a raw material containing fibers other than kapok fiber, and obtaining a card sliver A2 from the wrap.
(3) a step of combining a plurality of card slivers A1 and drawing them to obtain a drawn sliver S1, and a step of combining a plurality of card slivers A2 and drawing them to obtain a drawn sliver S2;
(4) a step of using a drawn sliver S1 as a core sliver and winding a drawn sliver S2 as a sheath sliver around the drawn sliver S1 while spinning to obtain a roving yarn having a two-layer structure; and (5) a step of drawing the roving yarn and then twisting it.
17. A method for producing a two-layer structure spun yarn, comprising the following steps (1) to (5):
(1) A process of using a raw material containing kapok fiber and an oil agent to prepare a sheet-like wrap by a mixed cotton process, and obtaining a carded sliver A2 from the wrap; (2) A process of using a raw material containing fibers other than kapok fiber and an oil agent to prepare a sheet-like wrap by a mixed cotton process, and obtaining a carded sliver A1 from the wrap; (3) A process of combining and drawing a plurality of carded slivers A2 to obtain a drawn sliver S2, and a process of combining and drawing a plurality of carded slivers A1 to obtain a drawn sliver S1; (4) A process of using the drawn sliver S1 as a core sliver, and spinning the drawn sliver S2 as a sheath sliver while winding it around the drawn sliver S1 to obtain a roving having a two-layer structure;
(5) A method for producing a two-layer spun yarn, comprising the step of twisting the roving after drawing the roving.

According to the present invention, it is possible to provide a two-layer spun yarn containing kapok fiber which has practical strength, is less susceptible to scattering or falling off of kapok fibers due to abrasion during weaving or knitting, enables weaving and knitting with good operability, and takes advantage of the inherent characteristics of kapok fiber, namely light weight and bulkiness.

More specifically, the spun yarn of the present invention has a two-layer structure derived from a core sliver and a sheath sliver, and at least one of the layers contains kapok fiber. This prevents the kapok fiber from scattering or falling off from the yarn surface due to friction during weaving and knitting, making it possible to weave and knit with good operability.

In particular, in the two-layer spun yarn containing kapok fiber in the core, in addition to the above-mentioned effects, uniform dyeability can be obtained. Generally, kapok fiber has a hollow portion and a relatively high hollow ratio of about 70 to 80%. Therefore, it is difficult to dye it to a desired color, and due to the above-mentioned weaving or knitting defects, woven and knitted fabrics obtained from spun yarn containing kapok fiber are difficult to obtain uniform dyeability and are prone to dye spots. In contrast, the two-layer spun yarn containing kapok fiber in the core of the present invention has a small amount of kapok fiber present on the spun yarn surface and relatively few yarn spots, and therefore can obtain good and uniform dyeability. As a result, such a two-layer spun yarn can provide a woven and knitted fabric with few weaving or knitting defects and excellent lightness, bulkiness, dyeability, etc. Such a woven and knitted fabric can be suitably used for clothing applications such as socks, underwear, innerwear, and outerwear.

In addition, in the case of a two-layer spun yarn containing kapok fiber in the sheath, thread breakage or slippage during weaving or knitting can be prevented, and there is relatively little unevenness in the thread, making it possible to weave and knit with good operability. As a result, the two-layer spun yarn containing kapok fiber in the sheath of the present invention can provide a woven or knitted fabric that has few defects in weaving or knitting, is high quality, and is also lightweight and bulky. Furthermore, the kapok fiber contained in the sheath can create a linen-like texture, and can be dyed to give it a casual appearance. Therefore, the above woven and knitted fabric can also be suitably used for clothing applications such as socks, underwear, innerwear, and outerwear.

FIG. 1 is a schematic cross-sectional view showing an example of a roving machine for obtaining a two-layer structure spun yarn of the present invention. FIG. 1 is a schematic cross-sectional view showing an example of a roving machine for obtaining a two-layer structure spun yarn of the present invention. FIG. 1 is a schematic diagram showing a layer structure of a preferred embodiment of a two-layer spun yarn of the present invention.

The two-layer structure spun yarn of the present invention (spun yarn of the present invention) is a spun yarn having a core derived from a core sliver and a sheath derived from a sheath sliver,
(1) In a cross section perpendicular to the longitudinal direction of the spun yarn, a core portion is disposed at the center of the cross section, and a sheath portion is disposed around the core portion,
(2) At least one of the core and the sheath contains kapok fiber;
(3) The content of kapok fiber in the spun yarn is 20 to 60% by mass.
It is characterized by:

As described above, the present invention is a two-layer structure spun yarn in which, in a cross section perpendicular to the longitudinal direction of the spun yarn, a core is disposed at the center of the cross section and a sheath is disposed around the core. That is, preferred embodiments of the present invention include two forms, namely, a form in which the core contains kapok fiber (hereinafter referred to as the "first invention") and a form in which the sheath contains kapok fiber (hereinafter referred to as the "second invention").

A sliver is a thread made by lining up individual strands of kapok fiber or the like that have been loosened and processed into a string-like shape.

FIG. 3 shows a schematic diagram of an embodiment of the spun yarn of the present invention. In the two-layer spun yarn 10 according to the first invention, a core 11 derived from a core sliver (yarn body) is formed, and a sheath 12 derived from a sheath sliver is formed so as to surround the periphery (side surface) of the core in the longitudinal direction. As in the two-layer spun yarn 10, in a cross section perpendicular to the longitudinal direction of the yarn, the central circle is substantially constituted by the cross section of the core 11, and the approximately doughnut-shaped area around it is constituted by the cross section of the sheath 12. That is, the core derived from the core sliver is an approximately solid yarn body, and the sheath 12 derived from the sheath sliver is an approximately tubular yarn body. In the two-layer spun yarn 10 according to the first invention, the core 11 contains kapok fiber, and the sheath 12 contains fibers other than kapok fiber, which is a preferred embodiment of the first invention.

On the other hand, in the two-layer spun yarn 10' according to the second invention, a core 11 derived from a core sliver (yarn body) is formed, and a sheath 12 derived from a sheath sliver is formed so as to surround the periphery (side surface) of the core in the longitudinal direction. As in the two-layer spun yarn 10', in a cross section perpendicular to the longitudinal direction of the yarn, the central circle is substantially formed by the cross section of the core 11, and the approximately doughnut-shaped area around it is formed by the cross section of the sheath 12. That is, the core derived from the core sliver is an approximately solid yarn body, and the sheath 12 derived from the sheath sliver is an approximately tubular yarn body. In the two-layer spun yarn 10' according to the second invention, the sheath 12 contains kapok fiber, and the core 11 contains at least chemical fiber, which is a preferred embodiment of the second invention.

In the present invention, as described later, the core sliver and the sheath sliver are combined in the form of a sliver (yarn body) in the manufacturing process, and then the sliver is stretched and twisted to obtain a two-layer spun yarn. That is, the core 11 derived from the core sliver refers to the core sliver that has been stretched, twisted, and other processes in the two-layer spun yarn in the above manufacturing process. Similarly, the sheath 12 derived from the sheath sliver refers to the sheath sliver that has been stretched, twisted, and other processes in the two-layer spun yarn in the above manufacturing process.

In the following, the first and second aspects of the present invention, which are preferred embodiments of the present invention, will be described in order.

A. First Invention A-1. Two-layered spun yarn of the first invention The two-layered spun yarn of the first invention is one in which at least the core contains kapok fiber. More specifically, it is a spun yarn formed from a core sliver and a sheath sliver, in which the core is formed from the core sliver containing kapok fiber in a manufacturing process described below, and the sheath is formed by winding the sheath sliver around the core sliver. In other words, the two-layered spun yarn of the first invention is a spun yarn whose cross section perpendicular to the longitudinal direction of the yarn is composed of two layers, a core and a sheath formed around it, the core contains kapok fiber, and the sheath contains fibers other than kapok fiber.

In the embodiment of the first invention, it is preferable that the core contains kapok fiber, and the sheath is composed of a fiber other than kapok fiber (particularly at least one of chemical fiber and natural fiber other than kapok fiber). It is more preferable that the sheath contains cotton. The sheath may contain kapok fiber, but it is preferable that it does not contain kapok fiber.

In the two-layer spun yarn of the first invention, the mass ratio between the core and sheath is not limited, but it is usually preferable that the core:sheath = 40% by mass:60%-85% by mass:15% by mass, with the total of the two being 100% by mass.

(1) Core The core is derived from the core sliver. The technical meaning of being derived from the core sliver is as explained above.

The core in the first invention contains kapok fiber, and the content of kapok fiber in the spun yarn of the present invention is set to 20 to 55% by mass (preferably 25 to 50% by mass). If the content is less than 20% by mass, the light weight, bulkiness, etc., of the kapok fiber cannot be fully obtained. On the other hand, if the content exceeds 55% by mass, it becomes difficult to produce the two-layered spun yarn of the first invention, and the kapok fiber will be present in large amounts on the yarn surface or will fall off from the yarn surface.

The content of the kapok fiber in the core is not limited, but is usually preferably 40% by mass or more, and more preferably 45% by mass or more. The upper limit of the content is not limited, and the core may be made of only kapok fiber (i.e., 100% by mass of kapok fiber), but from the viewpoint of operability, it is preferable that the content of the kapok fiber is 80% by mass or less, with the remainder being the second fiber described below.

The fiber length of the kapok fiber used in the first invention is not limited, but from the viewpoint of strength when spun into yarn and weaving and knitting properties, it is preferable that the fiber diameter is relatively small and the fiber length is relatively long. More specifically, the average fiber length is preferably 11 to 18 mm. Also, it is desirable that the average fiber diameter is 20 to 28 μm. Furthermore, it is preferable that the hollow rate is 70 to 80%. Such kapok fiber can be a commercially available product.

It is preferable that the kapok fiber raw cotton contains as little contaminants as possible, such as seeds, fruit skins, and polypropylene, which is a material used to form packaging materials.

The core may contain fibers other than kapok fibers (hereinafter, in the present invention, unless otherwise specified, fibers other than kapok fibers will be referred to as "second fibers").

The second fiber may be at least one organic fiber selected from chemical fibers and natural fibers other than kapok fibers. Commercially available products may also be used as the second fiber. It is preferable to use the second fiber in combination with kapok fibers from the viewpoint of improving dyeability and texture while taking advantage of the characteristics of kapok fibers, which are natural fibers. In other words, it is more preferable to use at least one of a) chemical fibers and b) natural fibers other than kapok fibers.

The chemical fibers include at least one of synthetic fibers, semi-synthetic fibers, and regenerated fibers.

Examples of synthetic fibers include polyester, polyamide (nylon), acrylic, polyolefin, para-aramid, meta-aramid, polyarylate, and the like.

The semi-synthetic fibers include, for example, cellulosic semi-synthetic fibers such as diacetate and triacetate.

Examples of regenerated fibers include cellulose-based regenerated fibers such as viscose rayon and Tencel (modal, lyocell).

As the natural fiber other than kapok fiber, plant fiber or animal fiber can be preferably used. Plant fiber includes, for example, cotton, hemp, etc. Animal fiber includes, for example, wool, silk, etc. In the present invention, for example, cotton can be preferably used as the second fiber.

From the viewpoint of making the two-layered spun yarn superior in strength and elongation, it is preferable to use a synthetic fiber as the second fiber. In particular, it is more preferable to use a polyester fiber among the synthetic fibers, from the viewpoint of improving strength and minimizing yarn unevenness.

The second fibers may be either long fibers or short fibers, but are particularly preferably short fibers, and the fiber length in this case may be appropriately adjusted depending on the type of short fibers used.

In particular, in the present invention, when the second fiber is a chemical fiber, the fiber length is usually about 20 to 50 mm, preferably 25 to 45 mm, and more preferably 30 to 40 mm. Also, it is preferable that the second fiber has a substantially uniform fiber length. By controlling the fiber length of the second fiber within the above range, the core sliver containing the kapok fiber and the second fiber can be more reliably uniform, and scattering of the kapok fiber can be effectively suppressed during the manufacturing process of the two-layer spun yarn, thereby making it possible to obtain a two-layer spun yarn with less yarn unevenness and superior strength.

For the same reasons as in the case of chemical fibers, when the second fiber is a natural fiber, the fiber length is usually preferably about 21.4 to 36.5 mm, more preferably 26.2 to 36.5 mm, and most preferably 28.6 to 36.5 mm.

Here, in the present invention, the fiber length of the chemical fiber is a value measured according to the method described in "a) Staple diagram method (Method A)" of "8.4.1 Average fiber length" of Japanese Industrial Standard JIS L 1015:2010 "Testing methods for staple fibers of chemical fibers." In addition, when the second fiber is a natural fiber, the fiber length is a value measured as an effective fiber length based on Japanese Industrial Standard JIS L1019 7.2.1 (Double sorter method).

When the second fiber is a chemical fiber, the single fiber fineness is not particularly limited, but is usually preferably in the range of 0.5 to 6.0 dtex, and more preferably 1.0 to 5.0 dtex. When the second fiber is a natural fiber, the average micronaire fineness is preferably 2.7 to 5.5 μg/2.54 cm, and more preferably 3.3 to 5.2 μg/2.54 cm.

Here, the fineness (average fineness) of the chemical fibers is a value measured based on the Japanese Industrial Standards JIS L1015 8.5.1 Correct Fineness Method A. The average fineness of the natural fibers is a value measured based on the Micronaire fineness (JIS L1019 7.4.1 (Micronaire method)).

When the core contains the second fiber, the mass ratio of the kapok fiber to the second fiber is not limited, but is preferably (kapok fiber):(second fiber)=40% by mass:60% to 80% by mass:20% by mass, assuming the sum of the two fibers to be 100% by mass. If the mass ratio satisfies the above range, the obtained two-layer spun yarn not only fully retains the excellent lightness and bulkiness of the kapok fiber, but also makes use of the properties of the second fiber. In addition, since the core is well-balanced, it is also possible to effectively prevent the kapok fiber from scattering or falling off during the manufacturing process.

(2) Sheath The sheath is derived from the sheath sliver. The technical meaning of being derived from the sheath sliver is as explained above.

In consideration of operability, dyeability, texture, etc., it is desirable for the fiber used in the sheath to contain the second fiber and a small amount of or no kapok fiber. More specifically, the kapok fiber is preferably present in an amount of about 0 to 5% by mass in the sheath, more preferably 0 to 1% by mass, and most preferably 0% by mass.

As the second fiber, at least one organic fiber selected from chemical fibers and natural fibers other than kapok fibers can be preferably used. Therefore, for example, cotton can be preferably used as the second fiber. When the second fiber is used in combination with the core, the second fiber used in the sheath may be the same as or different from the second fiber in the core.

The chemical fibers include at least one of synthetic fibers, semi-synthetic fibers, and regenerated fibers.

Examples of synthetic fibers include polyester, polyamide (nylon), acrylic, polyolefin, para-aramid, meta-aramid, polyarylate, and the like.

The semi-synthetic fibers include, for example, cellulosic semi-synthetic fibers such as diacetate and triacetate.

Examples of regenerated fibers include cellulose-based regenerated fibers such as viscose rayon and Tencel (modal, lyocell).

As the natural fiber other than kapok fiber, either plant fiber or animal fiber can be used. Examples of plant fiber include cotton and hemp. Examples of animal fiber include wool and silk. Examples of natural fiber include cotton. Therefore, in a preferred embodiment, in consideration of the dyeability or texture of the resulting woven or knitted fabric, cotton is used in the sheath, and the cotton content in the sheath is 20% by mass or more (preferably 40% by mass or more). In this case, the upper limit of the cotton content can be, for example, 100% by mass, but is not limited thereto. Therefore, for example, the cotton content in the sheath can be set to 90 to 100% by mass.

The second fibers may be either long fibers or short fibers, but it is particularly preferable to use short fibers. When short fibers are used, the fiber length may be appropriately adjusted depending on, for example, the type of short fibers used.

In particular, in the present invention, when the second fiber is a chemical fiber, the fiber length is usually about 20 to 50 mm, preferably 25 to 45 mm, and more preferably 30 to 40 mm. In addition, it is preferable that the second fiber has a substantially uniform fiber length. By controlling the fiber length of the second fiber within the above range, the sheath sliver containing the kapok fiber and the second fiber can be more reliably uniform, and scattering of the kapok fiber can be effectively suppressed during the manufacturing process of the two-layer spun yarn, thereby making it possible to obtain a two-layer spun yarn with less yarn unevenness and superior strength.

For the same reasons as in the case of chemical fibers, when the second fiber is a natural fiber, the fiber length is usually preferably 21.4 to 36.5 mm, more preferably 26.2 to 36.5 mm, and most preferably 28.6 to 36.5 mm.

Here, in the present invention, the fiber length of the chemical fiber is a value measured according to the method described in "a) Staple diagram method (Method A)" of "8.4.1 Average fiber length" of Japanese Industrial Standard JIS L 1015:2010 "Testing methods for staple fibers of chemical fibers." In addition, when the second fiber is a natural fiber, the fiber length is a value measured as an effective fiber length based on Japanese Industrial Standard JIS L1019 7.2.1 (Double sorter method).

When the second fiber is a chemical fiber, the single fiber fineness is not particularly limited, but is preferably in the range of 0.5 to 6.0 dtex, and more preferably 1.0 to 5.0 dtex. When the second fiber is a natural fiber, the average micronaire fineness is preferably 2.7 to 5.5 μg/2.54 cm, and more preferably 3.3 to 5.2 μg/2.54 cm.

Here, the fineness (average fineness) of the chemical fibers is a value measured based on the Japanese Industrial Standards JIS L1015 8.5.1 Correct Fineness Method A. The average fineness of the natural fibers is a value measured based on the Micronaire fineness (JIS L1019 7.4.1 (Micronaire method)).

(3) Characteristics of the two-layer spun yarn of the first invention The average tenacity of the two-layer spun yarn of the first invention is not limited, but is usually preferably 120 cN or more, and more preferably 140 to 500 cN. If it is less than 120 cN, the operability of weaving or knitting a woven or knitted fabric may deteriorate, and the resulting woven or knitted fabric may have poor durability. On the other hand, in order to achieve an average tenacity of more than 500 cN, the count of the two-layer spun yarn must be made small, which tends to make it unsuitable for clothing applications. As a method for setting the average tenacity within the above range, for example, a method of changing at least one of the type of fiber used, the single fiber fineness, etc. can be preferably adopted.

The tenacity variation rate of the two-layer spun yarn of the first invention is not limited, but is usually preferably 5 to 15%, and more preferably 8 to 12%. The elongation is not limited, but is usually preferably 4 to 20%, and more preferably 5 to 15%. By setting the tenacity variation rate and/or elongation rate within the above ranges, the uniformity of the yarn is improved, the operability during weaving or knitting of woven or knitted fabrics is improved, and the obtained woven or knitted fabrics are also more durable.

Furthermore, the two-layer spun yarn of the first invention is preferably a twisted yarn from the viewpoint of suppressing the falling off of the kapok fibers due to rubbing during weaving or knitting. Therefore, in the case of a twisted yarn, the twist coefficient K is preferably 3.8 or more, and more preferably 4.2 to 4.8. In this way, the two-layer spun yarn of the present invention has an appropriate twist, which suppresses the loss of kapok fibers during the subsequent weaving and knitting processes, and is excellent in weaving and knitting properties. If the twist coefficient K is too low, the yarn is likely to break due to the unevenness of the twist. On the other hand, if the twist coefficient K is too high, it may easily lead to defects such as deterioration of productivity, hardening of the texture, or poor seams and snare.

The twist coefficient K can be calculated as follows.
Twist factor (K) = number of twists (number of twists/2.54 cm)/√(British cotton count)

The two-layer spun yarn of the first invention preferably has a Worcester unevenness (U%) of 25.0% or less, more preferably 20% or less, and most preferably 17% or less. If U% is within the above range, yarn breakage or loose threads are reduced even when the two-layer spun yarn of the first invention is used for weaving or knitting, and knitting properties are good. In the present invention, a card sliver containing a large amount of kapok fiber can be obtained by carrying out a manufacturing method as described below, and therefore a two-layer spun yarn having the above-mentioned characteristic values, low U%, and no yarn unevenness can be obtained. In the present invention, for example, kapok fiber and polyester fiber other than kapok fiber are used for the core sliver, making it possible to further reduce U%. The lower limit of U% is usually about 10% in consideration of the range of British cotton counts of spun yarns used for clothing applications, but is not limited thereto.

When the two-layer structure spun yarn of the first invention is used for clothing applications such as socks, underwear, mid-layer clothing, and outerwear, it is particularly preferable that the British cotton count is 5 to 60, and more preferably 10 to 50.

<Preferred embodiment of the first aspect of the invention>
As a preferred embodiment of the two-layer spun yarn of the first invention, the following composition can be adopted. The composition of the core can be 1) 40 to 65% by mass of kapok fiber, 2) 0 to 60% by mass of chemical fiber, and 3) 0 to 60% by mass of natural fiber other than kapok fiber. The composition of the sheath can be 1) 90 to 100% by mass of natural fiber other than kapok fiber, 2) 0 to 10% by mass of chemical fiber, and 3) 0 to 5% by mass of kapok fiber.

A-2. Manufacturing method of the two-layer spun yarn of the first invention The manufacturing method of the two-layer spun yarn of the first invention is not particularly limited as long as it can form the desired two-layer structure, but the manufacturing method described below can more reliably obtain a two-layer spun yarn.

That is, the two-layer structure spun yarn of the first invention is produced by the following steps (1) to (5):
(1) A process of producing a sheet-shaped wrap by a mixed cotton processing using a raw material containing kapok fiber and an oil agent, and obtaining a card sliver A1 from the wrap (card sliver A1 production process);
(2) A process of producing a sheet-shaped wrap by a mixed cotton processing using a raw material containing fibers other than kapok fiber, and obtaining a card sliver A2 from the wrap (card sliver A2 production process);
(3) A process of combining a plurality of card slivers A1 and drawing them to obtain a drawn sliver S1, and a process of combining a plurality of card slivers A2 and drawing them to obtain a drawn sliver S2 (drawn sliver preparation process);
(4) a step of obtaining a roving having a two-layer structure by using a drawn sliver S1 as a core sliver and winding a drawn sliver S2 as a sheath sliver around the drawn sliver S1 while spinning (roving step); and (5) a step of drawing the roving and then twisting it (spinning step).
In the following, one embodiment of the method for obtaining the two-layer spun yarn of the first invention will be described with reference to the drawings.

In a preferred embodiment of the method for obtaining a two-layered spun yarn with a core-sheath structure by combining in a roving process, two types of slivers, a sliver S1 containing kapok fiber to be the sliver for the core and a sliver S2 to be the sliver for the sheath, are prepared, and in the roving process, the sliver S1 is roved to be the core, and the sliver S2 is wound around the sliver S1 to form the sheath, followed by fine spinning to obtain a two-layered spun yarn. Each of the above steps will be described below.

Carded Sliver A1 Production Step In the carded sliver A1 production step, a raw material containing kapok fiber and an oil agent is used to produce a sheet-like wrap by a cotton-blending process, and the carded sliver A1 is obtained from the wrap.

More specifically, to obtain the card sliver A1 containing kapok fiber, kapok fiber is mixed with a second fiber as required and fed into a blowing machine to obtain a sheet-shaped wrap. In this case, it is difficult to obtain a sheet-shaped wrap containing a relatively large amount of kapok fiber while suppressing the scattering of kapok fiber using a normal blowing method. In contrast, the manufacturing method of the present invention makes it possible to obtain a sheet-shaped wrap by selecting an optimal feed speed while spraying an appropriate amount of spinning oil suitable for kapok fiber.

As the oil, commercially available textile oils for spinning can be used. In particular, it is preferable to use a surfactant as the oil, and among them, it is more preferable to use a nonionic surfactant. As the nonionic surfactant, at least one of ester type, ether type, ester-ether type, etc. can be mentioned. In particular, in the present invention, ether type surfactants (particularly polyoxyethylene alkyl ether surfactants) are preferable. As such surfactants, commercially available products can also be used. For example, "Marpoteron LE" manufactured by Matsumoto Yushi Seiyaku Co., Ltd. can be suitably used.

The amount of the oil used is not limited, but is preferably 0.05 to 0.3 mass % based on the total mass of the kapok fibers and the second fibers, and more preferably 0.08 to 0.2 mass %. By setting the amount within this range, the friction between the fibers in the carding process can be increased, and the convergence can be further improved.

The method of applying the oil to the kapok fiber is not particularly limited, and for example, a method of preparing a dilution of the oil to a concentration of 1.0 to 5.0% and spraying the diluted solution evenly onto the fiber surface of the raw kapok fiber to oil the kapok fiber can be suitably adopted. The timing of applying the oil to the kapok fiber is not limited, but it is desirable to apply the oil at least before the kapok fiber is subjected to the mixed cotton treatment.

The method for producing the sheet-like wrap and the method for obtaining the carded sliver A1 from the wrap may be carried out in the same manner as in the known methods. They may also be carried out using known or commercially available devices. For example, the raw materials are fed into a mixing and punching machine to obtain a sheet-like wrap, and the obtained wrap is then fed into a carding machine, and a carding process is carried out in the carding machine. After that, a web is spun, bundled, and pressed with a calendar roll to obtain a carded sliver containing kapok fiber. In this manner, the core sliver A1 constituting the core can be suitably obtained.

Carded Sliver A2 Production Step In the carded sliver A2 production step, a raw material containing fibers other than kapok fiber is used, and a sheet-like wrap is produced by a mixed cotton processing, and the carded sliver A2 is obtained from the wrap.

The card sliver A2 production process may basically be carried out in the same manner as the card sliver A1 production process.

The raw material may contain a small amount of kapok fiber as an optional component. In such a case, an oil agent can be appropriately blended into the raw material. This makes it possible to more reliably obtain a sheet-shaped wrap even when the raw material contains kapok fiber. The type and amount of oil agent used may be the same as those of the card sliver A1.

In the drawing sliver producing process, a plurality of card slivers A1 are joined together and drawn to obtain a drawn sliver S1, and a plurality of card slivers A2 are joined together and drawn to obtain a drawn sliver S2.

The method of producing the drawn sliver may be carried out in the same manner as known methods. It may also be carried out using known or commercially available drawing machines. For example, in the drawing process, a plurality of card slivers containing kapok fiber alone are combined and drawn to obtain a core sliver S1 containing kapok fiber. On the other hand, to obtain a sheath sliver S2, a card sliver can be obtained in the same manner as above using, for example, natural fibers or chemical fibers other than kapok fiber.

When multiple types of fibers are used, they are mixed in a mixing and wiping process (i.e., the card sliver A1 production process or the card sliver A2 production process) to obtain a sheet-like wrap, and then a card sliver is obtained in the same manner as described above.

Roving Step In the roving step, a drawn sliver S1 is used as a core sliver, and a drawn sliver S2 is used as a sheath sliver while being wound around the drawn sliver S1, thereby obtaining a roving having a two-layer structure.

The roving step can be carried out by using a known or commercially available device. For example, using a roving frame having the structure shown in Fig. 1 (schematic cross-sectional view) and Fig. 2 (schematic cross-sectional view), a sliver S1 and a sliver S2 are supplied as shown in Fig. 2, and the sliver S1 is drawn through the back roller (A), the intermediate roller (B), the apron (C), and the front roller (D) in this order. The sliver S1 is then wound around the sliver S2 at an angle θ of 60° to the flyer head (E) relative to the draft direction in Fig. 2, and the sliver S2 is wound around the sliver S1 while being given a false twist effect by the flyer (F), thereby forming a two-layer structure yarn (roving yarn (G)) in which the sliver S1 serves as the core and the sliver S2 serves as the sheath.

The number of twists in the roving step is preferably set to an extent that does not cause poor drawing in the subsequent fine spinning step, and for example, the twist coefficient K can be adjusted to about 0.4 to 1.5. Here, the mass ratio of the core sliver to the sheath sliver is preferably adjusted to (core sliver):(sliver)=20:80 to 80:20, and it is particularly preferable to set the distribution in consideration of various factors such as the specific gravity, strength, and crimp of the fibers.

In the spinning process, the roving is stretched and then twisted. In this case, the spinning process can be carried out using a known or commercially available spinning machine. For example, the roving is passed through a trumpet (guide) of the spinning machine, passed through a back roller, an apron, and a front roller in this order, stretched, and then twisted to obtain the two-layered spun yarn of the first invention.

The number of twists in the spinning process is not limited, but from the viewpoint of suppressing the fall-off of kapok fibers due to abrasion during weaving or knitting, it is preferable that the twist coefficient K is 3.8 or more, and more preferably 4.2 to 4.8.

A-3. Woven/knitted fabrics The present invention includes woven/knitted fabrics containing the two-layer spun yarn of the first invention. The content of the two-layer spun yarn of the present invention contained in the woven/knitted fabric is usually preferably 50% by mass or more, and more preferably 70% by mass or more. Of these, it is most preferable that the content is 100% by mass (i.e., a woven/knitted fabric using only the two-layer spun yarn of the present invention).

The woven or knitted fabric is not particularly limited in structure. Examples of woven fabrics include plain, twill, satin, pile, and variations of these structures. Knitted fabrics may be either warp knitted fabrics or weft knitted fabrics. Examples of warp knitted fabrics include denby knitted fabrics, cord knitted fabrics, and atlas knitted fabrics, and more specifically, tricot half and tricot satin. Examples of weft knitted fabrics include plain knitted fabrics, rib knitted fabrics, purl knitted fabrics, and smooth knitted fabrics, and more specifically, jersey, pique, and smooth knitted fabrics.

The woven or knitted fabric of the present invention includes the two-layered spun yarn of the first invention, which is a spun yarn in which the longitudinal periphery of a core containing kapok fiber is covered with a sheath. Therefore, compared with spun yarns in which kapok fiber is present in large amounts on the yarn surface (such as ordinary blended yarns), the woven or knitted fabric has superior weaving, knitting, dyeability, etc. In other words, defects in weaving and knitting caused by scattering of kapok fiber, etc. can be suppressed, and the woven or knitted fabric of the present invention can have fewer fabric defects, dyeing spots, etc.

B. Second Invention B-1. Two-layered spun yarn of the second invention The two-layered spun yarn of the second invention is one in which at least the sheath contains kapok fiber. More specifically, it is a spun yarn formed from a core sliver and a sheath sliver, and the sheath is formed by winding the sheath sliver containing kapok fiber around the core sliver in a manufacturing process described below. In other words, it is a spun yarn whose cross section perpendicular to the longitudinal direction of the yarn is composed of two layers, a core and a sheath formed around it, the core containing the second fiber, and the sheath containing kapok fiber.

In the two-layer spun yarn of the second invention, the mass ratio of the core to the sheath is not limited, but when the sum of the two is taken as 100% by mass, it is usually preferable that the core:sheath ratio be 20-80% by mass:80-20% by mass, and particularly preferably 30-60% by mass:70-40% by mass.

(1) Core The core is derived from the core sliver. The technical meaning of being derived from the core sliver is as explained above.

In the second invention, the core contains chemical fibers, and the content of the chemical fibers in the core is usually preferably 50% by mass or more, more preferably 55 to 100% by mass, and most preferably 60 to 100% by mass. If the content of the chemical fibers in the core is less than 50% by mass, the two-layer spun yarn of the second invention will not have sufficient strength, and as will be described later, the uniformity of the core sliver supplied in the roving step during the production of the two-layer spun yarn will be poor, making the obtained spun yarn prone to yarn unevenness and causing phenomena such as yarn breakage, which may result in poor knitting properties.

There is no upper limit on the amount of chemical fiber contained, and for example, the core may contain 100% by mass of chemical fiber. However, from the viewpoint of improving the composite (covering property) between the core sliver and the sheath sliver during production, it is preferable that the core contains 60 to 90% by mass of chemical fiber, with the remainder being at least one type of natural fiber (including kapok fiber).

The content of chemical fibers in the two-layer spun yarn is not limited, but is usually preferably about 20 to 60% by mass, and more preferably 25 to 50% by mass. If the content of chemical fibers is within the above range, the two-layer spun yarn as a whole will have sufficient strength. In addition, since the amount of chemical fibers is not too large, the yarn surface can be appropriately covered by the kapok fiber of the sheath and fibers other than the kapok fiber.

Here, the chemical fiber may be at least one of synthetic fiber, semi-synthetic fiber, and regenerated fiber.

Examples of synthetic fibers include polyester, polyamide (nylon), acrylic, polyolefin, para-aramid, meta-aramid, polyarylate, and the like.

The semi-synthetic fibers include, for example, cellulosic semi-synthetic fibers such as diacetate and triacetate.

Examples of regenerated fibers include cellulose-based regenerated fibers such as viscose rayon and Tencel (modal, lyocell).

As the natural fiber, either plant fiber or animal fiber can be used. As the plant fiber, for example, cotton, hemp, kapok fiber, etc. can be mentioned. As the animal fiber, for example, wool, silk, etc. can be mentioned. As the natural fiber, for example, cotton can be preferably used.

In general, when kapok fiber is blended with other fibers to produce spun yarn, the fiber length of the kapok fiber is shorter than that of the other fibers, and this difference in fiber length results in yarn unevenness. Yarn unevenness refers to, for example, thick and thin portions (i.e., large and small average counts on the same spun yarn) in the longitudinal direction of the spun yarn, or the existence of such unevenness in thickness in multiple locations in the longitudinal direction of the yarn.

In spun yarn with yarn unevenness, the twist is concentrated in the small details when the yarn is twisted, so the twist is not applied properly to the thick parts, which can lead to problems such as fibers falling out of the spun yarn (a phenomenon known as "slip-out"). The thick parts can also get caught on the reed during weaving, causing the yarn to break, or seam marks can occur when the small details are knitted during knitting.

When using kapok fiber, which has a shorter fiber length than the cotton fiber or synthetic staple fiber used in general cotton spinning, the above-mentioned yarn unevenness is likely to occur in the spun yarn obtained by mixing the various fibers in the carding process or by mixing the various fiber slivers in the drawing process, which is usually carried out to obtain a blended yarn.

In the second invention, from the viewpoint of strength and less yarn unevenness, it is preferable to use synthetic fibers (particularly polyester fibers) as the constituent material of the core. In this case, the natural fibers used in combination with the synthetic fibers can be suitably selected from those exemplified above. That is, at least one of natural fibers (e.g., plant fibers such as cotton, hemp, and kapok fibers, and animal fibers such as wool and silk), semi-synthetic fibers, and regenerated fibers can be used. Among these, it is preferable to use fibers similar to those usable for the sheath portion described later, and at least one of kapok fibers, cotton, and lyocell can be suitably used, for example.

The chemical fibers, etc. used in the core are preferably short fibers, and the fiber length may be adjusted appropriately depending on the type of short fiber used. In particular, in the present invention, the fiber length is usually about 20 to 50 mm, particularly preferably 25 to 45 mm, and more preferably 30 to 40 mm. In addition, it is preferable that the fiber length is substantially uniform. If the fiber length of the chemical fibers, etc. is within the above range, the sliver containing the chemical fibers used in the core in the manufacturing process of the two-layered spun yarn described below will be uniform, have little yarn unevenness, and have excellent strength, so that the two-layered spun yarn of the present invention obtained by compounding kapok fiber also has sufficient strength and further has little yarn unevenness.

The fiber length is a value measured according to the method described in "a) Staple diagram method (Method A)" of "8.4.1 Average fiber length" of Japanese Industrial Standard JIS L 1015:2010 "Testing methods for staple chemical fibers".

The single fiber fineness of the chemical fiber is not particularly limited, but is usually preferably in the range of 0.5 to 6.0 dtex, and more preferably in the range of 1.0 to 5.0 dtex. The above-mentioned fineness (average fineness) of the chemical fiber is in accordance with Japanese Industrial Standard JIS L1015 8.5.1
This is a value measured based on the correct fineness A method.

When the core contains natural fibers, the fiber length, average fineness, etc. of the natural fibers may be the same as those in the first invention.

The above-mentioned chemical fibers may be solid or hollow, but in order to make the two-layered spun yarn of the second invention lighter and bulkier, the chemical fibers in the core may have a hollow cross section. Therefore, for example, hollow synthetic fibers (e.g., hollow polyester fibers) can be preferably used. Such hollow synthetic fibers may be commercially available.

(2) Sheath The sheath is derived from the sheath sliver. The technical meaning of being derived from the sheath sliver is as explained above.

The sheath contains kapok fiber, and the content of kapok fiber in the sheath is usually about 30 to 60% by mass, preferably 35 to 55% by mass. If the content of kapok fiber in the sheath is less than 30% by mass, the light weight and bulkiness of the kapok fiber may not be fully exhibited. On the other hand, if the content of kapok fiber exceeds 60% by mass, it becomes difficult to obtain a sliver for the sheath in the manufacturing method described below. Even if a sliver is obtained, the two-layer spun yarn may have many yarn irregularities, or the kapok fiber may easily fall off or scatter from the yarn surface.

The content of kapok fiber in the two-layer spun yarn is preferably 20 to 60% by mass, more preferably 25 to 50% by mass. If the content of kapok fiber is within the above range, the two-layer spun yarn will have less yarn breakage and will have excellent lightness and bulkiness.

The kapok fiber used in the second invention preferably has a small fiber diameter and a long fiber length from the viewpoint of strength when spun into yarn and ease of weaving and knitting. Specifically, the average fiber length is preferably 11 to 18 mm. The average fiber diameter is preferably 20 to 28 μm. The hollow ratio is preferably 70 to 80%. Commercially available kapok fibers can also be used.

In addition, it is preferable that the kapok fiber has little contaminants such as seeds and fruit skins, and little contaminant such as polypropylene, which is a material used to form packaging materials, in the raw cotton.

The sheath may contain a fiber other than kapok fiber. As such a fiber, the above-mentioned second fiber can be used. That is, at least one of chemical fibers and natural fibers other than kapok fiber can be suitably used. In particular, from the viewpoint of obtaining good texture and dyeability while taking advantage of the characteristics of kapok fiber, which is a natural fiber, it is preferable to use at least one of natural fibers other than kapok fiber and regenerated cellulose fiber as the second fiber, and it is more preferable to use at least one of cotton and lyocell.

The second fibers may be the same as those usable in the core portion.

In particular, it is preferable that the sheath contains cotton as a natural fiber other than kapok fiber in order to suppress scattering of kapok fiber or unevenness of the yarn surface, to facilitate obtaining a sliver for the sheath in the manufacturing method described below, and from the viewpoint of texture, etc. In this case, the content of cotton in the sheath is preferably 30% by mass or more, and more preferably 40% by mass or more. The upper limit of the content can be, for example, 50% by mass, but is not limited thereto.

The cellulose-based fiber, whether used for the core or the sheath, preferably has a fiber length of 20 to 51 mm, more preferably 30 to 40 mm, and the single fiber fineness is preferably in the range of 0.5 to 6.0 dtex, more preferably 1.0 to 5.0 dtex.

(3) Characteristics of the two-layer spun yarn of the second invention The average strength of the two-layer spun yarn of the second invention is 120 cN or more, preferably 140 to 500 cN, and more preferably 200 to 500 cN. If it is less than 120 cN, the operability of weaving or knitting a woven or knitted fabric may be poor, and the resulting woven or knitted fabric may be inferior in durability. On the other hand, in order to achieve an average strength of more than 500 cN, the count of the two-layer spun yarn must be small, which tends to make it unsuitable for clothing applications. The average strength also varies depending on the type of fiber used, the single fiber fineness, etc., and for example, the larger the single fiber fineness of the fiber used, the smaller the average strength tends to be.

The two-layer spun yarn of the second invention has a tenacity fluctuation rate of 5 to 20%, and more preferably 8 to 17%, and an elongation rate of 4 to 20%, and more preferably 5 to 15%. When the tenacity fluctuation rate and elongation rate are within the ranges specified in the present invention, the operability in weaving or knitting a woven or knitted fabric is improved, and a woven or knitted fabric having superior durability can be obtained.

Furthermore, the two-layered spun yarn of the second invention is preferably a twisted yarn from the viewpoint of preventing the kapok fibers from falling off due to friction during weaving or knitting. Therefore, when it is a twisted yarn, the twist coefficient K is preferably 3.8 or more, and more preferably 4.2 to 4.8. In this way, the two-layered spun yarn of the present invention has an appropriate twist, which suppresses the falling off of the kapok fibers during the subsequent weaving and knitting processes, and is excellent in weaving and knitting properties. If the twist coefficient K is too low, the spun yarn is prone to yarn breakage due to the unevenness of the twist. On the other hand, if the twist coefficient K is too high, it may easily lead to defects such as deterioration of productivity, hardening of the texture, or poor seams and snare.

The twist coefficient K can be calculated as follows.
Twist factor (K) = number of twists (number of twists/2.54 cm)/√(British cotton count)

Since the two-layer structure spun yarn of the second invention is suitable for clothing applications such as socks, underwear, mid-layer clothing, and outerwear, the British cotton count is preferably 5 to 60, and more preferably 10 to 50.

The two-layer spun yarn of the second invention preferably has a Worcester unevenness (U%) of 25.0% or less, particularly preferably 20% or less, and even more preferably 17% or less. If U% is 25% or less, particularly preferably 17% or less, yarn breakage or loose threads are reduced and good knitting properties can be obtained even when the two-layer spun yarn of the second invention is used for weaving or knitting. The lower limit of U% is usually about 10% in consideration of the range of British cotton counts of spun yarns used for clothing applications, but is not limited thereto.

In the second invention, by adopting a two-layer structure having a core containing a specific amount of chemical fibers with uniform fiber length and a sheath containing a specific amount of kapok fiber, it is possible to provide a two-layer spun yarn having the above-mentioned characteristic values, a low U% and little yarn unevenness. In addition, by carrying out the manufacturing method described below, it is possible to obtain a two-layer spun yarn having a low U% and little yarn unevenness even if the spun yarn contains a large amount of kapok fiber on the fiber surface.

<Preferred embodiment of the second aspect of the invention>
As a preferred embodiment of the two-layer spun yarn of the second invention, the following composition can be adopted. The composition of the core can be 1) 50 to 100% by mass of synthetic fiber, 2) 0 to 25% by mass of semi-synthetic fiber and/or regenerated fiber, and 3) 0 to 25% by mass of kapok fiber. The composition of the sheath can be 1) 40 to 60% by mass of kapok fiber, and 2) 40 to 60% by mass of at least one of natural fiber, semi-synthetic fiber, and regenerated fiber.

B-2. Manufacturing method of the two-layer spun yarn of the second invention The manufacturing method of the two-layer spun yarn of the second invention is not particularly limited as long as it can form the desired two-layer structure. In particular, the manufacturing method described below can more reliably produce a two-layer spun yarn.

That is, the two-layer structure spun yarn of the second invention is produced by the following steps (1) to (5):
(1) A process of producing a sheet-shaped wrap by a mixed cotton processing using a raw material containing kapok fiber and an oil agent, and obtaining a card sliver A2 from the wrap (card sliver A2 production process)
(2) A process of producing a sheet-shaped wrap by a mixed cotton processing using a raw material containing fibers other than kapok fiber, and obtaining a card sliver A1 from the wrap (card sliver A1 production process);
(3) A process of combining a plurality of card slivers A2 and drawing them to obtain a drawn sliver S2, and a process of combining a plurality of card slivers A1 and drawing them to obtain a drawn sliver S1 (drawn sliver preparation process);
(4) a step of using the drawn sliver S1 as a core sliver and winding the drawn sliver S2 as a sheath sliver around the drawn sliver S1 while spinning to obtain a roving having a two-layer structure (roving step); and (5) a step of drawing the roving and then twisting it (spinning step).
In the following, one embodiment of the method for obtaining the two-layer spun yarn of the second invention will be described with reference to the drawings.

In a method for obtaining a two-layer spun yarn with a core-sheath structure by combining in a roving process, as a preferred embodiment, two types of slivers, a sliver S1 containing chemical fibers and a sliver S2 containing kapok fibers, are prepared in the roving process, and sliver S1 is used as the core and sliver S2 is wound around sliver S1 to form a sheath portion, followed by roving to obtain a two-layer spun yarn of the second invention.

Card sliver A2 production process In the card sliver A2 production process, a short fiber raw material containing kapok fiber and an oil agent is used, and a sheet-like wrap containing 30% or more by mass of kapok fiber is produced by a mixed cotton processing, and card sliver A2 is obtained from the wrap.

More specifically, to obtain a card sliver containing kapok fiber, kapok fiber is mixed with a second fiber as required and fed into a blowing machine to obtain a sheet-shaped wrap. In this case, it is difficult to obtain a sheet-shaped wrap containing a relatively large amount of kapok fiber while suppressing the scattering of kapok fiber with a normal blowing method of spinning. In contrast, the manufacturing method of the present invention makes it possible to obtain a sheet-shaped wrap by selecting an optimal feed speed while spraying an appropriate amount of spinning oil suitable for kapok fiber.

As the oil, commercially available textile oils for spinning can be used, and it is particularly preferable to use a surfactant, and among them, it is more preferable to use a nonionic surfactant. As the nonionic surfactant, at least one of ester type, ether type, ester-ether type, etc. can be mentioned. In particular, in the present invention, ether type surfactants (particularly polyoxyethylene alkyl ether surfactants) are preferable. As such surfactants, commercially available products can also be used. For example, "Marpoteron LE" manufactured by Matsumoto Yushi Seiyaku Co., Ltd. can be preferably used.

The amount of the oil used is not limited, but is preferably 0.05 to 0.3 mass % based on the total mass of the kapok fibers and the second fibers, and more preferably 0.08 to 0.2 mass %. By setting the amount within this range, the friction between the fibers in the carding process can be increased, and the convergence can be further improved.

The method of applying the oil to the kapok fiber is not particularly limited, and for example, a method of preparing a diluted solution of the oil to a concentration of about 1.0 to 5.0% and spraying the diluted solution evenly onto the fiber surface of the raw kapok fiber to apply oil can be suitably adopted. The timing of applying the oil to the kapok fiber is not limited, but it is desirable to apply the oil at least before the fiber is subjected to the mixed cotton treatment.

The method for producing the sheet-like wrap and the method for obtaining the carded sliver A2 from the wrap may be carried out in the same manner as known methods. They may also be carried out using known or commercially available devices. For example, the raw materials are fed into a mixing and punching machine to obtain a sheet-like wrap, and the obtained wrap is then fed into a carding machine, and a carding process is carried out in the carding machine. After that, a web is spun, bundled, and pressed with a calendar roll to obtain a carded sliver containing kapok fibers. In this manner, the core sliver A2 constituting the core can be suitably obtained.

Carded Sliver A1 Production Step In the carded sliver A1 production step, a raw material containing fibers other than kapok fiber is used, and a sheet-like wrap is produced by a mixed cotton processing, and the carded sliver A1 is obtained from the wrap.

The card sliver A1 production process may basically be carried out in the same manner as the card sliver A2 production process.

The above "raw material containing fibers other than kapok fiber" means a raw material containing at least "fibers other than kapok fiber" and does not exclude the inclusion of kapok fiber. Therefore, the raw material may contain kapok fiber as an optional component. When the raw material contains kapok fiber, an oil agent can be appropriately blended into the raw material. This makes it possible to more reliably obtain a sheet-shaped wrap even when the raw material contains kapok fiber. The type and amount of oil agent used can be the same as those of the card sliver A1.

In the drawing sliver preparation process, a plurality of card slivers A2 are joined together and drawn to obtain a drawn sliver S2, and a plurality of card slivers A1 are joined together and drawn to obtain a drawn sliver S1.

The method for producing the drawn sliver may be carried out in the same manner as known methods. It may also be carried out using known or commercially available drawing machines. For example, in the drawing process, a plurality of card slivers containing kapok fiber alone are combined and drawn to obtain a sheath sliver S2 containing kapok fiber. On the other hand, to obtain a core sliver S1, a card sliver can be obtained in the same manner as above using natural or chemical fibers.

When multiple types of fibers are used, they are mixed in the blending process (i.e., the card sliver A1 production process or the card sliver A2 production process) to obtain a sheet-like wrap, and then a card sliver is obtained in the same manner as described above.

Roving Step In the roving step, a drawn sliver S1 is used as a core sliver, and a drawn sliver S2 is used as a sheath sliver while being wound around the drawn sliver S1, thereby obtaining a roving having a two-layer structure.

The roving step can be carried out by using a known or commercially available device. For example, a roving machine having a structure shown in FIG. 1 (schematic cross-sectional view) and FIG. 2 (schematic cross-sectional view) is used, and slivers S1 and S2 are supplied as shown in FIG. 2, and drawn through the back roller (A), intermediate roller (B), apron (C), and front roller (D). The angle θ of the sliver S1 to the flyer head (E) relative to the draft direction in FIG. 2 is set to 60°, and the sliver S2 is wound around the sliver S1. The sliver S1 is wound while being given a false twist effect by the flyer (F), to form a two-layer structure yarn (roving (G)) in which the sliver S1 is the core and the sliver S2 is the sheath. The two-layer structure spun yarn of the second invention can be obtained by passing this roving through the trumpet (guide) of the spinning machine, drawing through the back roller, apron, and front roller, and then twisting.

The number of twists in the roving step is preferably set to an extent that does not cause poor drawing in the subsequent fine spinning step, and for example, the twist coefficient K can be adjusted to about 0.4 to 1.5. Here, the mass ratio of the core sliver to the sheath sliver is preferably adjusted to (core sliver):(sliver)=20:80 to 50:50, and it is particularly preferable to set the distribution in consideration of various factors such as the specific gravity, strength, and crimp of the fibers.

In the spinning process, the roving is stretched and then twisted. In this case, the spinning process can be carried out using a known or commercially available spinning machine. For example, the roving is passed through a trumpet (guide) of the spinning machine, passed through a back roller, an apron, and a front roller in this order, stretched, and then twisted to obtain the two-layered spun yarn of the second invention.

The number of twists in the spinning process is not particularly limited, but from the viewpoint of preventing the kapok fibers from falling off due to friction during weaving or knitting, it is preferable that the twist coefficient K is 3.8 or more, and more preferably 4.2 to 4.8.

The two-layered spun yarn of the second invention has sufficient strength, and although the sheath contains a large amount of kapok fiber, with the content of kapok fiber in the sheath being 30 to 60% by mass, it is characterized by having few defects caused by yarn unevenness during weaving or knitting. The reason why it is possible to obtain a two-layered spun yarn having the above characteristics is considered to be as follows from the viewpoint of the manufacturing method.

Usually, when a blended spun yarn is obtained using a plurality of types of fibers, the fibers are blended in a blending process, or card slivers of each fiber are overlapped (doubling) in a drawing process.

In the drawing process, multiple card slivers with uneven thickness are stacked together and then stretched, which has the effect of making the thickness unevenness uniform. Meanwhile, in the roving and fine spinning processes following the drawing process, in a general spinning method, a single sliver obtained through the drawing process or a single roving obtained through the roving process is stretched and twisted in the roving or fine spinning process to obtain a general spun yarn.

In the above-mentioned drawing, roving and spinning processes, the fiber bundles such as slivers and rovings can be stretched by varying the rotation speeds of the rollers or aprons.

At this time, the distance between each roller or aprons must be appropriately set taking into consideration the maximum fiber length of the short fibers used. If the distance between each roller or aprons is shorter than the maximum fiber length of the short fibers used, this leads to breakage of the short fibers and poor stretching. Conversely, if the distance between each roller or aprons is too wide, there will be a lot of floating fibers that are not held by the rollers or aprons between the rollers or aprons, resulting in a fiber bundle with poor uniformity and large unevenness.

In particular, when using staple fibers with significantly different fiber lengths, it is necessary to set the distance between each roller or aprons to match the staple fibers with longer fiber lengths. Therefore, the staple fibers with shorter fiber lengths tend to become floating fibers between each roller or aprons at a higher rate, and the resulting fiber bundle may have poor uniformity and large irregularities.

For the reasons mentioned above, in a spinning method for obtaining a blended spun yarn using multiple types of fibers, fiber bundles such as card slivers of multiple types of fibers are usually doubled in the drawing process to obtain a drawn sliver with less fiber bundle unevenness and more uniformity than the card sliver from the previous process. However, when attempting to obtain a spun yarn that mixes short fibers such as kapok fibers and long fibers such as chemical fibers, as in the spun yarn of the present invention, the short fibers used are not uniform in fiber length, and therefore the short fibers become floating fibers due to drawing in the roving or fine spinning process following the drawing process, and the resulting blended yarn is prone to yarn unevenness.

The manufacturing method of the second invention is characterized in that the doubling and compounding of the sliver containing a large amount of chemical fiber and the sliver containing a large amount of kapok fiber to obtain a two-layered spun yarn is not performed in the drawing process, but each sliver is also doubling and compounded in the roving process. That is, in the drawing process, a sliver S1 containing a large amount of chemical fiber and a sliver S2 containing a large amount of kapok fiber, both of which have the same fiber length, are obtained, and in the subsequent roving process, the slivers S1 and S2 are each drawn and then compounded to form a core-sheath structure, thereby obtaining the same effect as doubling.

By manufacturing the yarn in this manner, the number of drawing steps required when chemical fibers and kapok fibers are combined, i.e., when there is a difference in the fiber length of the short fibers, can be reduced, resulting in a spun yarn with less yarn unevenness as a whole.

Furthermore, in the second invention, the core is made of a sliver containing at least 50% by mass of chemical fibers having uniform fiber length, and the sliver in the core has excellent strength and little unevenness in the yarn, so that the two-layered spun yarn of the present invention obtained by incorporating kapok fiber also has sufficient strength and little unevenness in the yarn. As a result, even when the obtained two-layered spun yarn is used for weaving or knitting, there is little breakage or slipping out of the yarn.

B-3. Woven/knitted fabrics The present invention encompasses woven/knitted fabrics containing the two-layer spun yarn of the second invention. The content of the two-layer spun yarn of the present invention contained in the woven/knitted fabric is preferably 50% by mass or more, more preferably 70% by mass or more, and most preferably 100% by mass (i.e., a woven/knitted fabric using only the two-layer spun yarn of the second invention).

The woven or knitted fabric is not particularly limited in terms of structure. Examples of the woven fabric include plain, twill, satin, pile, and variations of these structures. The knitted fabric may be either a warp knit or a weft knit. Examples of the warp knit include denby knit, cord knit, and atlas knit, and more specifically, tricot half and tricot satin. Examples of the weft knit include plain knit, rib knit, purl knit, and smooth knit, and more specifically, jersey, pique, and smooth.

The woven or knitted fabric of the second invention includes the two-layered spun yarn of the second invention, and the kapok fiber is present in a large amount on the surface of the yarn due to the kapok fiber arranged in the sheath. Therefore, the fabric is not only lightweight and bulky, but also has a linen-like texture and can be dyed to give it a casual appearance.

The present invention will be described in more detail below with reference to examples and comparative examples, although the present invention is not limited to these examples.
<A. Examples of the First Invention>
(1) Regarding characteristic values, etc. Various characteristic values and evaluation methods in the examples related to the first invention are as follows.

[Measurement of count]
The obtained spun yarn was used and measured in accordance with Japanese Industrial Standard JIS L-1095 9.4.1.

[Measurement of twist number]
The obtained spun yarn was used and measured in accordance with the method B of Japanese Industrial Standard JIS L-1095 9.15.1.

[Average strength and elongation]
The obtained spun yarn was subjected to a tensile test in accordance with Japanese Industrial Standard JIS L-1095 under the conditions of a tensile speed of 30 cm/min and a gripping distance of 50 cm using a tensile tester: Shikishima Boseki ST-2000.
Measured according to 9.5.
The number of measurement samples was 5 randomly selected cheeses, each of which was measured 10 times, and the average values of the 50 measurements were taken as the average strength and elongation.

[Strong fluctuation rate]
The strength variation rate was calculated from the total of 50 measured values when measuring the average strength described above using the following formula.
Strong fluctuation rate (%) = (strong standard deviation) / (strong average) x 100

[Worcester spots (U%)]
The obtained spun yarn was used to measure the unevenness in accordance with the method A of JIS L-1095 9.20.1 under the conditions of a measurement speed of 200 m/min and a measurement time of 2 minutes using a yarn unevenness tester (KET-80V/B manufactured by Keisokuki Kogyo Co., Ltd.).

[Knitting]
Using only the obtained spun yarn, knitting was carried out on a circular knitting machine, and the knitting properties were evaluated on the following three-level scale.
The circular knitting machine used had a bobbin diameter of 30 inches and a gauge of 22, and the number of yarns fed was 24. The knitting tension, stitch count, etc. were appropriately adjusted, and a 40 m length of grey fabric was knitted in a plain weave, after which the number of defects and penalty points was counted.
The defects and penalty points counted were limited to only splices, nicks, and needle marks, and did not include stains, sink marks, neps, joints, etc.
When the defect was within 20 ^cm2 , one point was given, and when the defect was not within 20 ^cm2 but was within the entire width of 20 cm in length, three points were given as penalty points. Based on the above criteria for defects and penalty points, the evaluation was made based on the total penalty points given when inspecting a 40 m length of the grey fabric.
◯: The total of defects and penalty points is less than 4 points. △: The total of defects and penalty points is 4 points or more but less than 7 points. ×: The total of defects and penalty points is 7 points or more.

[Lightweight and bulky]
The resulting processed fabric was evaluated by the evaluators based on the feel according to the following two-level scale.
◯: Excellent in lightness and bulkiness.
×: Lightness and bulkiness are normal or poor.

[Dyeability]
The resulting processed fabric was visually evaluated by an evaluator on the following two-level scale.
○: Dyed to the desired color.
×: Not dyed to the desired color (dye spots present).

(2) Regarding the fibers used, etc. The kapok fiber, cotton fiber and polyester staple fiber used in the examples are as follows.

[Kapok fiber (G1)]
Manufactured by PT Randu Indo Prima, produced in East Java, Indonesia, average fiber diameter 21.5 μm, average fiber length 14.6 mm.
The average fiber diameter is measured by the Boken Quality Evaluation Organization, a general incorporated foundation, in accordance with the Japanese Industrial Standards JIS L
1030 Applied mutatis mutandis The average long diameter of the kapok fiber was determined and calculated by measuring the width using a microscope.
The average fiber length was calculated by the Boken Quality Evaluation Organization, a general incorporated foundation, by determining the average fiber length of kapok fibers according to the Japanese Industrial Standard JIS L 1015 synthetic fiber staple test method.

[Cotton fiber (G2)]
Organic cotton from India, BUNNY BRAHMA medium-length cotton class (fiber length 1.1/8 to 1.5/16 inches (28.6 mm to 33.3 mm), cotton thickness 3.5 to 4.9 micronaires, fiber strength 28 GPT (g/tex) or more)

[Polyester staple fiber (G3)]
Indorama Polyester Industries PCL. 100% POLYESTER STAPLE FIBER 1.2D x 38mm SEMI DULL RAW WHITE, fiber length: 38mm, fineness: 1.2 Denier

(3) Examples and Comparative Examples [Example 1-1]
(Sliver S1: core sliver)
The kapok fiber (G1) and the cotton fiber (G2) were weighed to have the same mass and fed onto the lattice of a cotton-mixing machine. At this time, in order to prevent the kapok fiber from scattering, a spinning oil agent (Marpoteron LE, manufactured by Matsumoto Yushi Seiyaku Co., Ltd.), which increases the friction between the fibers and improves the convergence of the raw cotton, was diluted and sprayed onto the fibers (the final amount of oil applied was 0.1% by mass).
The raw cotton to which this oil agent had been applied was fed sequentially into each process of a cotton-mixing and punching machine, and the conditions of each machine were adjusted so that the feed speed of the raw cotton was appropriate, thereby obtaining a sheet-like wrap made of kapok fiber/cotton fiber.
This wrap was fed into a carding machine, and after undergoing a carding process in the carding machine, a web was spun, bundled, and pressed with a calendar roll to obtain a carded sliver of 340 gr/6 yd (hereinafter, gr: 1 grain = 0.06479891 grams, yd: 1 yard = 0.9144 meters).
Next, the card sliver was drawn twice in a drawing process, with the total of eight pieces being drawn 8.5 times, to obtain a sliver S1 of 300 gr/6 yd.
(Sliver S2: Sliver for sheath)
Cotton fibers (G2) were fed into a cotton-blending machine to obtain a sheet-like wrap made of cotton fibers. The wrap was fed into a carding machine, and after a carding process in the carding machine, a web was spun, bundled, and pressed with a calendar roll to obtain a carded sliver of 380 gr/6 yd.
Next, the card sliver was drawn twice in a drawing process to a total of 11.0 times the original length for all eight strands, to obtain a sliver S2 of 200 gr/6 yd.
A sliver S1 was prepared as the core sliver, and a sliver S2 was prepared as the sheath sliver.
Using a roving frame having the structure shown in Figure 1 (schematic cross-sectional view) and Figure 2 (schematic cross-sectional view), a core sliver S1 and a sheath sliver S2 were supplied and drawn 7.0 times, and the mass ratio of each sliver was set to S1:S2 = 60:40. The advance angle θ of the core sliver S1 to the flyer head relative to the draft direction in Figure 2 was set to 60°, and the sheath sliver S2 was wound around the core sliver S1 while twisting in the Z direction to give a twist coefficient of 1.6, thereby obtaining a core-sheath structured roving with a roving mass of 360 gr/30 yd and a twist number of 1.33 times/2.54 cm.
This roving was passed through the trumpet (guide) of a spinning machine, passed through a back roller, an apron, and a front roller in that order, and stretched 24.5 times. It was then twisted in the Z direction to a twist factor of 4.5 (twist count 18.0 times/2.54 cm), to obtain a two-layered spun yarn of 16.5 count (British cotton count).

[Example 1-2]
A two-layer spun yarn was obtained in the same manner as in Example 1-1, except that the same roving as in Example 1-1 was used, the roving was drawn 32.9 times using a spinning frame, and then twisted in the Z direction to a twist factor of 4.5 (twist number 20.6 times/2.54 cm).

[Examples 1-3]
Using the same sliver S1 and sliver S2 as in Example 1-1, a core-sheath roving was obtained in the same manner as in Example 1, except that the sliver S1 and sliver S2 were drawn 9.3 times in a roving frame and then twisted in the Z direction to give a twist coefficient of 1.7.
This roving was passed through the trumpet (guide) of a spinning machine, passed through a back roller, an apron, and a front roller in that order, and drawn 37.6 times. A two-layer spun yarn was obtained in the same manner as in Example 1-1, except that the roving was twisted in the Z direction to a twist factor of 4.5 (twist number 25.5 times/2.54 cm).

[Examples 1 to 4]
A two-layer spun yarn was obtained in the same manner as in Example 1-1, except that the same roving as in Example 1-1 was used, the roving was drawn 32.9 times using a spinning frame, and then twisted in the Z direction to a twist coefficient of 3.8 (twist number 17.4 times/2.54 cm).

[Examples 1 to 5]
A two-layer spun yarn was obtained in the same manner as in Example 1-1, except that the same roving yarn as in Example 1-1 was used, drawn 32.9 times in a spinning frame, and then twisted in the Z direction to a twist coefficient of 5.2 (twist number 23.8 times/2.54 cm).

[Examples 1 to 6]
(Sliver S1: core sliver)
Kapok fiber (G1) and cotton fiber (G2) were weighed out so that the mass ratio of raw cotton fed into the cotton-blending machine was G1:G2 = 62.5:37.5, and the procedure was then repeated in the same manner as in Example 1 to obtain a sheet-like wrap consisting of kapok fiber/cotton fiber.
This wrap was fed into a carding machine and carded therein, after which a web was spun, bundled and pressed with a calendar roll to obtain a carded sliver of 340 gr/6 yd.
Next, this card sliver was drawn twice in a drawing process to a total of 6.7 times the length of the eight strands, to obtain a sliver S1 of 480 gr/6 yd.
(Sliver S2: Sliver for sheath)
A 380 gr/6 yd card sliver made of the cotton fiber described in Example 1-1 was drawn twice in a drawing process to a total of 10.7 times the original length for all six fibers to obtain a 120 gr/6 yd sliver S2.
A roving having a core-sheath structure with a roving weight of 360 gr/30 yd and a twist number of 1.33 turns/2.54 cm was obtained in the same manner as in Example 1-1, except that the core sliver S1 and the sheath sliver S2 were used and drawn 8.4 times in the roving process.
This roving was passed through the trumpet (guide) of a spinning machine, passed through a back roller, an apron, and a front roller in that order, and drawn 32.9 times. A two-layer spun yarn was obtained in the same manner as in Example 1-1, except that the roving was twisted in the Z direction to a twist factor of 4.5 (twists 20.6 times/2.54 cm).

[Examples 1 to 7]
(Sliver S1: core sliver)
The same settings as in Example 1-1 were used except that the cotton fiber (G2) was changed to polyester staple fiber (G3), to obtain a 300 gr/6 yd sliver S1 made of kapok fiber/polyester staple fiber.
(Sliver S2: Sliver for sheath)
A 200 gr/6 yd sliver S2 made of cotton fibers was prepared similarly to that in Example 1-1.
A roving yarn having a core-sheath structure with a roving yarn mass of 360 gr/30 yd and a twist number of 1.03 turns/2.54 cm was obtained in the same manner as in Example 1-1, except that the slivers S1 and S2 were twisted in the Z direction by a roving frame to give a twist coefficient of 1.2.
This roving was passed through the trumpet (guide) of a spinning machine, passed through a back roller, an apron, and a front roller in that order, and drawn 24.5 times. A two-layer spun yarn was obtained in the same manner as in Example 1-1, except that the roving was twisted in the Z direction to a twist factor of 4.5 (twist number 18.0 turns/2.54 cm).

[Examples 1 to 8]
A two-layer spun yarn was obtained in the same manner as in Example 1-7, except that the same roving as in Example 1-7 was used, the roving was drawn 32.9 times using a spinning frame, and then twisted in the Z direction to a twist factor of 4.5 (twist number 32.9 times/2.54 cm).

[Examples 1 to 9]
The same slivers S1 and S2 as those in Example 1-7 were used, and after drawing them 9.3 times in a roving frame, they were twisted in the Z direction to give a twist coefficient of 1.3. In the same manner as in Example 1-7, a roving yarn having a core-sheath structure with a roving yarn mass of 270 gr/30 yd and a twist number of 1.29 times/2.54 cm was obtained.
This roving was passed through the trumpet (guide) of a spinning machine, passed through a back roller, an apron, and a front roller in that order, and drawn 37.6 times. A two-layer spun yarn was obtained in the same manner as in Example 1-7, except that the roving was twisted in the Z direction to a twist factor of 4.5 (twist number 25.5 times/2.54 cm).

[Examples 1-10]
A two-layer spun yarn was obtained in the same manner as in Example 1-9, except that the same roving yarn as in Example 1-9 was used, drawn 46.7 times in a spinning frame, and then twisted in the Z direction to a twist factor of 4.5 (twist number 28.5 times/2.54 cm).

[Examples 1-11]
A two-layer spun yarn was obtained in the same manner as in Example 1-1, except that the same roving as in Example 1-1 was used and twisted in the Z direction using a spinning frame to give a twist coefficient of 3.6 (twist number 16.5 times/2.54 cm).

[Comparative Example 1-1]
Five 340 grain/6 yard card slivers made of kapok fiber/cotton fiber described in Example 1-1 and three 380 grain/6 yard card slivers made of cotton fiber described in Example 1-1 were used, and the eight were drawn together 7.5 times in the drawing process to obtain a 379 grain/6 yard rough sliver. Eight of these rough slivers were used and drawn again 7.5 times in the drawing process to obtain a 400 grain/6 yard sliver S3.
The sliver S3 was fed to a roving frame, stretched 6.3 times, and then twisted in the Z direction to a twist coefficient of 1.7 to obtain a normal blended roving having a roving mass of 320 grains/30 yards and a twist number of 1.50 turns/2.54 cm, which was not a two-layer structure yarn.
This roving was passed through the trumpet (guide) of a spinning machine, passed through a back roller, an apron, and a front roller in this order, and drawn 28.5 times. A blended spun yarn was obtained in the same manner as in Example 1-1, except that the roving was twisted in the Z direction to a twist factor of 4.5 (twist number 20.6 times/2.54 cm).

[Comparative Example 1-2]
A card sliver of 380 grains/6 yards made of the cotton fiber described in Example 1-1 was drawn twice in a drawing process to a total of 8.7 times the original length, to obtain a sliver S4 of 320 gr/6 yds.
The sliver S4 was fed to a roving frame, stretched 6.3 times, and then twisted in the Z direction to a twist coefficient of 1.7 to obtain a roving consisting only of cotton fibers with a roving mass of 320 grains/30 yards and a twist number of 1.50 turns/2.54 cm.
This roving was passed through the trumpet (guide) of a spinning machine, passed through a back roller, an apron, and a front roller in this order, and drawn 28.5 times. A blended spun yarn was obtained in the same manner as in Example 1-1, except that the roving was twisted in the Z direction to a twist coefficient of 3.8 (twist number 17.4 times/2.54 cm).

[Processing Example 1]
The knitting properties were evaluated as described above using only the spun yarns obtained in each of the Examples and Comparative Examples, and a plain stitch greige was knitted.
The obtained grey fabric was subjected to the dyeing and finishing treatments (scouring, bleaching, drying, dyeing, soaping, and final setting) described below to obtain a processed fabric.
In addition, in Examples 1-1 to 1-6, Example 1-11, and Comparative Examples 1-1 to 1-2, dyeing was performed with reactive dyes. In Examples 1-7 to 1-10, two-bath dyeing with a disperse dye and a reactive dye was performed, specifically, dyeing with a disperse dye was performed first, and then dyeing with a reactive dye was performed.
(refining and bleaching)
Sunmol FL 1g/l, caustic soda 5g/l, hydrogen peroxide 5g/l, bath ratio 1:50, boil x 30 minutes (dry)
Pin tenter, 120℃ x 2 minutes (dispersion dyeing) *When polyester fiber is included Disperse dye: Dianix Black 15% o.m.f, Nikka Sunsalt SN-130 0.5g/L, acetic acid 0.2g/L, bath ratio 1:30, 135℃ x 30 minutes (reduction cleaning) *When polyester fiber is included Hydrosaliphite 1g/L, sodium hydroxide 1g/L, Sunmol FL 1g/L, bath ratio 1:30, 80℃ x 20 minutes (reactive dyeing)
Reactive dye: Remazol Black RL Gr 8% o. m. f. , Glauber's salt 60g/l, soda ash 20g/l, bath ratio 1:30, 60°C x 60 minutes (soaping)
Lipotol RK-5 1g/l, boil for 10 minutes (final set)
Pin tenter, 170℃ x 1 min

[Test Example 1]
The evaluation results of the two-layer structure spun yarn obtained in each Example and Comparative Example, and the processed fabric obtained in Processing Example 1 are shown in Table 1. The evaluation contents and evaluation methods are as described above in "(1) Characteristic values, etc."

As is clear from Table 1, the two-layer spun yarns obtained in Examples 1-1 to 1-6 and 1-11 contained kapok fiber and cotton in the core sliver and the sheath sliver was composed of cotton. Since these satisfy the characteristic values specified in the present invention, the obtained knitted fabrics had few knitting defects and were excellent in lightness, bulkiness and dyeability.

In addition, the two-layer structure spun yarns obtained in Examples 1-7 to 1-10 contained kapok fiber and polyester fiber in the core sliver and satisfied the characteristic values specified in the present invention, so they had excellent strength and little yarn unevenness, and the obtained knitted fabrics had few knitting defects and were excellent in lightness, bulkiness, dyeability, etc.

<B. Examples of the Second Invention>
(1) Characteristic Values, etc. Various characteristic values and evaluation methods in the examples related to the second invention are as follows.

[Measurement of count]
The obtained spun yarn was used and the measurement was carried out in accordance with Japanese Industrial Standards JIS L-1095 9.4.1.

[Measurement of twist number]
The obtained spun yarn was used and measured in accordance with the method B of Japanese Industrial Standards JIS L-1095 9.15.1.

[Average strength and elongation]
The obtained spun yarn was subjected to a tensile test in accordance with Japanese Industrial Standard JIS L-1095 under the conditions of a tensile speed of 30 cm/min and a gripping distance of 50 cm using a tensile tester: Shikishima Boseki ST-2000.
Measured according to 9.5.
The number of measurement samples was 5 randomly selected cheeses, each of which was measured 10 times, and the average values of the 50 measurements were taken as the average strength and elongation.

[Strong fluctuation rate]
The strength variation rate was calculated from the total of 50 measured values when measuring the average strength described above using the following formula.
Strong fluctuation rate (%) = (strong standard deviation) / (strong average) x 100

[Worcester spots (U%)]
The obtained spun yarn was used to measure the unevenness in accordance with the method A of JIS L-1095 9.20.1 under the conditions of a measurement speed of 200 m/min and a measurement time of 2 minutes using a yarn unevenness tester (KET-80V/B manufactured by Keisokuki Kogyo Co., Ltd.).

[Knitting]
Using only the obtained spun yarn, knitting was carried out on a circular knitting machine, and the knitting properties were evaluated on the following three-level scale.
The circular knitting machine used had a bobbin diameter of 30 inches and a gauge of 22, and the number of yarns fed was 24. The knitting tension, stitch count, etc. were appropriately adjusted, and a 40 m length of grey fabric was knitted in a plain weave, after which the number of defects and penalty points was counted.
The defects and penalty points counted were limited to only splices, nicks, and needle marks, and did not include stains, sink marks, neps, joints, etc.
When the defect was within 20 ^cm2 , one point was given, and when the defect was not within 20 ^cm2 but was within the entire width of 20 cm in length, three points were given as penalty points. Based on the above criteria for defects and penalty points, the evaluation was made based on the total penalty points given when inspecting a 40 m length of the grey fabric.
〇: The total of defects and penalty points is less than 4 points. △: The total of defects and penalty points is 4 points or more but less than 7 points. ×: The total of defects and penalty points is 7 points or more.

[Covering properties]
The plain knitted fabric obtained in the above evaluation of [knitting property] was dyed and finished under the following conditions (scouring, bleaching, drying, dyeing, soaping, final setting) using a reactive dye that only dyes kapok fiber and cellulose, to obtain a processed knitted fabric. The obtained processed knitted fabric was visually evaluated by an evaluator on the following three-level scale.
◯: Excellent covering; the undyed polyester fibers of the core are not visible on the surface of the spun yarn (knitted fabric).
Δ: The covering property is slightly poor; some of the undyed polyester fibers of the core are visible on the surface of the spun yarn (knitted fabric).
x: Poor covering property; the polyester fibers of the core part that are not dyed on the surface of the spun yarn (knitted fabric) are completely exposed.
(Dyeing and finishing conditions)
Scouring and bleaching: Sunmol FL 1g/l, caustic soda 5g/l, hydrogen peroxide 5g/l, bath ratio 1:50, boil x 30 minutes Drying: pin tenter, 120°C x 2 minutes Dyeing: reactive dye; Remazol Black RL Gr 8% o.m.f., Glauber's salt 60g/l, soda ash 20g/l, bath ratio 1:30, 60°C x 60 minutes Soaping: Lipotol RK-5 1g/l, boil x 10 minutes Final set: pin tenter, 170°C x 1 minute

[Lightweight and bulky]
The resulting processed fabric was evaluated by the evaluators based on the feel according to the following four-point scale.
: Particularly excellent in lightness and bulkiness.
◯: Excellent lightness and bulkiness.
Δ: Lightweight feel and bulkiness are normal.
×: Poor lightness and bulkiness.

[Texture]
The resulting processed fabric was evaluated by the evaluators based on the feel according to the following two-level scale.
〇: Excellent linen-like texture.
×: The texture is inferior to that of linen.

(2) Regarding the fibers used, etc. The kapok fiber, cotton fiber, polyester staple fiber, hollow polyester staple fiber, and lyocell staple fiber used in the examples are as follows.

[Kapok fiber (G1)]
Manufactured by PT Randu Indo Prima, produced in East Java, Indonesia, average fiber diameter 21.5 μm, average fiber length 14.6 mm.
The average fiber diameter is measured by the Boken Quality Evaluation Organization, a general incorporated foundation, in accordance with the Japanese Industrial Standards JIS L
1030 Applied mutatis mutandis The average long diameter of the kapok fiber was determined and calculated by measuring the width using a microscope.
The average fiber length was calculated by the Boken Quality Evaluation Organization, a general incorporated foundation, by determining the average fiber length of kapok fibers according to the Japanese Industrial Standard JIS L 1015 synthetic fiber staple test method.

[Cotton fiber (G2)]
Organic cotton from India, BUNNY BRAHMA medium-length cotton class (fiber length 1.1/8 to 1.5/16 inches (28.6 mm to 33.3 mm), cotton thickness 3.5 to 4.9 micronaires, fiber strength 28 GPT (g/tex) or more)

[Polyester staple fiber (G3)]
Indorama Polyester Industries PCL. 100% POLYESTER STAPLE FIBER 1.2D x 38mm SEMI DULL RAW WHITE, fiber length: 38mm, fineness: 1.2 Denier

[Hollow polyester staple fiber (G4)]
Manufactured by Unitika Ltd., brand: 2.2T38mm, type: HR30, fiber length: 38.6mm, fineness: 2.50 dtex, strength: 2.50 cN/tex, elongation: 42.8%.

[Lyocell staple fiber (G5)]
Lenzing Fibers GmbH, LENZING Lyocell LF, 1.3 dtex 38 mm bright raw white, fiber length: 38 mm, fineness: 1.3 dtex

(3) Examples and Comparative Examples [Example 2-1]
(Kapok/cotton card sliver)
The kapok fiber (G1) and the cotton fiber (G2) were weighed to have the same mass and fed onto the lattice of a cotton-mixing machine. At this time, in order to prevent the kapok fiber from scattering, a spinning oil agent (Marpoteron LE, manufactured by Matsumoto Yushi Seiyaku Co., Ltd.), which increases the friction between the fibers and improves the convergence of the raw cotton, was diluted and sprayed onto the fibers (the final amount of oil applied was 0.1% by mass).
The raw cotton to which this oil agent had been applied was fed sequentially into each process of a cotton-mixing and punching machine, and the conditions of each machine were adjusted so that the feed speed of the raw cotton was appropriate, thereby obtaining a sheet-like wrap made of kapok fiber/cotton fiber.
This wrap was fed into a carding machine, and after undergoing a carding process in the carding machine, a web was spun, bundled, and pressed with a calendar roll to obtain a carded sliver of 320 gr/6 yd (hereinafter, gr: 1 grain = 0.06479891 grams, yd: 1 yard = 0.9144 meters).
(Card sliver made from polyester staple fiber)
The polyester staple fiber (G3) was fed into a punching machine to obtain a sheet-like wrap made of polyester staple fiber. The wrap was fed into a carding machine and carded in the carding machine, after which a web was spun, bundled, and pressed with a calendar roll to obtain a carded sliver made of polyester staple fiber having a diameter of 370 gr/6 yd.
(Sliver S1: core sliver)
One 320gr/6yd card sliver made of kapok fiber/cotton fiber and seven 370gr/6yd card slivers made of polyester staple fiber were used, and the eight pieces were drawn together 11.37 times in the drawing process to obtain a 256r/6yd rough sliver. The eight pieces of the rough sliver were again drawn together 11.37 times in the drawing process to obtain a 180gr/6yd sliver S1.
(Sliver S2: Sliver for sheath)
The card sliver made of kapok fiber/cotton fiber described above was used in the drawing process, and the eight fibers in total were drawn 7.60 times twice to obtain a sliver S2 of 355 gr/6 yd.
A sliver S1 was prepared as a sliver for the core portion, and a sliver S2 was prepared as a sliver for the sheath portion.
Using a roving frame having the structure shown in Figure 1 (schematic cross-sectional view) and Figure 2 (schematic cross-sectional view), a core sliver S1 and a sheath sliver S2 were supplied and drawn 7.5 times, and the mass ratio of each sliver was set to S1:S2 = 34:66. The advance angle θ of the core sliver S1 to the flyer head with respect to the draft direction in Figure 2 was set to 60°, and the sheath sliver S2 was wound around the core sliver S1 while twisting in the Z direction to give a twist coefficient of 1.21, thereby obtaining a core-sheath structured roving with a roving mass of 360 gr/30 yd and a twist number of 1.01 times/2.54 cm.
This roving was passed through the trumpet (guide) of a spinning machine, passed through the back roller, apron, and front roller in that order, and stretched 44.1 times. It was then twisted in the Z direction to a twist coefficient of 4.5 (twist count 25.6 times/2.54 cm), to obtain a two-layered spun yarn with a count of 31.1 (British cotton count).

[Example 2-2]
(Sliver S1: core sliver)
Three 320gr/6yd card slivers made of kapok fiber/cotton fiber described in Example 2-1 and five 281gr/6yd card slivers made of polyester staple fiber obtained by changing the card draft ratio in the manner described in Example 1 were used, and eight of them were drawn 10.25 times in a drawing process to obtain a 231gr/6yd rough sliver. Eight of these rough slivers were again drawn 10.25 times in a drawing process to obtain a 180gr/6yd sliver S1. (Sliver S2: Sliver for sheath)
On the other hand, as the sliver for the sheath portion, the same sliver S2 as in Example 2-1 was prepared.
Using the above-mentioned slivers S1 and S2, a roving yarn having a core-sheath structure with a roving yarn mass of 360 gr/30 yd and a twist number of 1.08 turns/2.54 cm was obtained in the same manner as in Example 2-1, except that the slivers were twisted in the Z direction by a roving frame to give a twist coefficient of 1.30.
This roving was passed through the trumpet (guide) of a spinning machine, passed through a back roller, an apron, and a front roller in that order, and drawn 44.09 times. A two-layer spun yarn was obtained in the same manner as in Example 2-1, except that the roving was twisted in the Z direction to a twist factor of 4.5 (twists 25.5 times/2.54 cm).

[Example 2-3]
(Sliver S1: core sliver)
Using the card sliver made of polyester staple fiber described in Example 2-1, a process of drawing 8 fibers in total at 9.37 times was carried out twice in the drawing process to obtain a sliver S1 of 270 gr/6 yd.
(Sliver S2: Sliver for sheath)
Using the card sliver made of kapok fiber/cotton fiber described in Example 2-1, a process of drawing 8 fibers in total to 8.71 times was carried out twice in the drawing process, to obtain a sliver S2 of 270 gr/6 yd.
The above-mentioned slivers S1 and S2 were used, and after drawing 7.5 times in a roving frame, the mass ratio of each sliver was set to S1:S2 = 50:50, and twisting was performed in the Z direction to give a twist coefficient of 1.11. In the same manner as in Example 2-1, a roving having a core-sheath structure with a roving mass of 360 gr/30 yd and a twist number of 0.92 turns/2.54 cm was obtained.
This roving was passed through the trumpet (guide) of a spinning machine, passed through a back roller, an apron, and a front roller in that order, and drawn 44.09 times. A two-layer spun yarn was obtained in the same manner as in Example 2-1, except that the roving was twisted in the Z direction to a twist factor of 4.5 (twists 25.5 times/2.54 cm).

[Example 2-4]
A two-layer spun yarn was obtained in the same manner as in Example 2-1, except that the same roving as in Example 2-1 was used and twisted in the Z direction using a spinning frame to give a twist coefficient of 3.8 (twist number 21.6 times/2.54 cm).

[Example 2-5]
Except for changing the polyester staple fiber (G3) of Example 2-1 to a hollow polyester staple fiber (G4), the same procedure as in Example 2-1 was followed to obtain a card sliver made of hollow polyester staple fiber, and then a core sliver S1 of 180 gr/6 yd was obtained.
Next, a two-layer spun yarn was obtained in the same manner as in Example 2-1, except that a sliver S1 made of hollow polyester staple fiber was used.

[Example 2-6]
A 278 gr/yd card sliver made of kapok fiber/lyocell staple fiber was obtained in the same manner as in Example 2-1, except that the cotton fiber (G2) described in Example 2-1 was changed to lyocell staple fiber (G5).
(Sliver S1: core sliver)
Two 278gr/6yd card slivers made of kapok fiber/lyocell staple fiber and six 370gr/6yd card slivers made of polyester staple fiber described in Example 2-1 were used, and the eight were combined and stretched 10.05 times in the drawing process to obtain a 276gr/6yd rough sliver. The eight rough slivers were again combined and stretched 10.05 times in the drawing process to obtain a 220gr/6yd sliver S1.
(Sliver S2: Sliver for sheath)
The card sliver made of the above-mentioned kapok fiber/lyocell staple fiber was used in the drawing process, and the eight fibers in total were drawn 7.03 times twice to obtain a sliver S2 of 360 gr/6 yd.
The above-mentioned slivers S1 and S2 were used, and after drawing 8.1 times in a roving frame, the mass ratio of each sliver was set to S1:S2 = 38:62, and twisting was performed in the Z direction to give a twist coefficient of 1.088. In the same manner as in Example 2-1, a roving having a core-sheath structure with a roving mass of 360 gr/30 yd and a twist number of 0.907 times/2.54 cm was obtained.
This roving was passed through the trumpet (guide) of a spinning machine, passed through a back roller, an apron, and a front roller in that order, and drawn 44.61 times. A two-layer spun yarn was obtained in the same manner as in Example 2-1, except that the roving was twisted in the Z direction to a twist factor of 4.5 (twists 25.6 times/2.54 cm).

[Example 2-7]
(Sliver S1: core sliver)
Four 320gr/6yd card slivers made of kapok fiber/cotton fiber described in Example 2-1 and four 258gr/6yd card slivers made of polyester staple fiber obtained by changing the draft ratio of the card in Example 2-1 were used, and the eight slivers were drawn 10.14 times in a drawing process to obtain a 228gr/6yd rough sliver. The eight slivers were drawn 10.14 times in a drawing process again to obtain a 180gr/6yd sliver S1.
(Sliver S2: Sliver for sheath)
As the sliver for the sheath portion, the same sliver S2 as in Example 2-1 was prepared.
Using the above-mentioned sliver S1 and sliver S2, a core-sheath roving was obtained in the same manner as in Example 2-1, except that the sliver S1 and sliver S2 were drawn 7.5 times in a roving frame and then twisted in the Z direction to give a twist coefficient of 1.30. The twist coefficient was 1.30.
This roving was passed through the trumpet (guide) of a spinning frame, passed through a back roller, an apron, and a front roller in this order, and drawn 44.09 times. A two-layer spun yarn was obtained in the same manner as in Example 2-1, except that the roving was twisted in the Z direction to a twist factor of 4.5 (twists 25.5 times/2.54 cm).

[Example 2-8]
A two-layer spun yarn was obtained in the same manner as in Example 2-1, except that the same roving as in Example 2-1 was used and twisted in the Z direction using a spinning frame to give a twist coefficient of 3.6 (twist number 20.4 turns/2.54 cm).

[Comparative Example 2-1]
Six card slivers of 320 gr/6 yd made of kapok fiber/cotton fiber described in Example 2-1 and two card slivers made of polyester staple fiber of 300 gr/6 yd made by changing the draft ratio of the card in Example 1 were used, and the eight slivers in total were stretched 7.09 times in the drawing process to obtain a rough sliver A1 of 355 gr/6 yd.
Next, five 320 gr/6 yd card slivers made of kapok fiber/cotton fiber described in Example 2-1 and three 300 gr/6 yd card slivers made of cotton fiber described in Example 2-1 were used, and the eight slivers in total were stretched 7.09 times in a drawing process to obtain a 353 gr/6 yd rough sliver A2.
Four of the rough slivers A1 and four of the rough slivers A2 were used again in the drawing process, and the eight were combined and drawn 7.09 times to obtain a sliver S3 of 400 gr/6 yd.
The sliver S3 was fed to a roving frame, stretched 6.25 times, and then twisted in the Z direction to a twist coefficient of 1.21 to obtain a roving in a normal blended state without a two-layer structure, with a roving mass of 320 grains/30 yards and a twist number of 1.07 turns/2.54 cm.
This roving was passed through the trumpet (guide) of a spinning machine, passed through a back roller, an apron, and a front roller in this order, and drawn 40.0 times. A blended spun yarn was obtained in the same manner as in Example 2-1, except that the roving was twisted in the Z direction to a twist factor of 4.5 (twists 25.6 times/2.54 cm).

[Comparative Example 2-2]
A two-layered spun yarn made of cotton fiber and polyester staple fiber was obtained in the same manner as in Example 2-1, except that the kapok fiber (G1) in Example 2-1 was replaced with cotton fiber (G2).

[Test Example 2]
The evaluation results of the two-layer structure spun yarn and knitted fabric obtained in each of the Examples and Comparative Examples are shown in Table 2. The evaluation contents and evaluation methods are as explained above in "(1) Characteristic values, etc."

As is clear from Table 2, the two-layer structure spun yarns obtained in Examples 2-1 to 2-8 satisfied the characteristic values specified in the present invention, and there was little yarn breakage or slipping out during knitting. In addition, the obtained knitted fabrics had few defects in knitting and were excellent in lightness, bulkiness, and texture.

On the other hand, in Comparative Example 2-1, polyester fibers, kapok fibers, and cotton fibers having different fiber lengths were blended, and therefore the obtained spun yarn had a mixture of the various fibers on the yarn surface, which made it prone to yarn breakage or slippage during knitting, and the knitting properties and feel were poor.

In Comparative Example 2-2, since the sheath did not contain kapok fiber, the obtained spun yarn was inferior in lightness, bulkiness and feel.

Claims (9)

A spun yarn having a core derived from a core sliver and a sheath derived from a sheath sliver,
(1) In a cross section perpendicular to the longitudinal direction of the spun yarn, a core portion is disposed at the center of the cross section, and a sheath portion is disposed around the core portion,
(2) At least one of the core and the sheath contains kapok fiber;
(3) The content of kapok fiber in the spun yarn is 20 to 60% by mass,
(4) The sheath sliver contains kapok fiber.
A two-layer spun yarn characterized by: 2. The two-layer spun yarn according to claim 1 , wherein the sheath sliver further comprises at least one of a) chemical fibers and b) natural fibers other than kapok fibers. 2. The two-layer spun yarn according to claim 1 , wherein the core sliver contains at least one of a) chemical fibers and b) natural fibers other than kapok fibers. The two-layer spun yarn according to claim 3 , wherein the chemical fibers have a fiber length of 20 to 50 mm. The two-layer spun yarn according to claim 3 , wherein the chemical fiber has a hollow portion in a cross-sectional shape of the fiber. 2. The two-layer spun yarn according to claim 1 , wherein the Worcester unevenness (U%) is 25.0% or less and the British cotton count is 5 to 60. The following characteristics:
(a) Average strength: 120 cN or more,
(b) Strong fluctuation rate: 4-20%;
The two-layer spun yarn according to claim 1 , which satisfies both of (c) elongation: 4 to 20% and (d) twist coefficient K: 3.8 or more. A woven or knitted fabric comprising the two-layered spun yarn according to claim 1 . A method for producing a two-layer structure spun yarn, comprising the following steps (1) to (5):
(1) A process of using a raw material containing kapok fiber and an oil agent to prepare a sheet-like wrap by a mixed cotton process, and obtaining a carded sliver A2 from the wrap; (2) A process of using a raw material containing fibers other than kapok fiber and an oil agent to prepare a sheet-like wrap by a mixed cotton process, and obtaining a carded sliver A1 from the wrap; (3) A process of combining and drawing a plurality of carded slivers A2 to obtain a drawn sliver S2, and a process of combining and drawing a plurality of carded slivers A1 to obtain a drawn sliver S1; (4) A process of using the drawn sliver S1 as a core sliver, and spinning the drawn sliver S2 as a sheath sliver while winding it around the drawn sliver S1 to obtain a roving having a two-layer structure;
(5) A method for producing a two-layer spun yarn, comprising the step of twisting the roving after drawing the roving.

Images