JP7286122B2 - Spun yarn and its manufacturing method - Google Patents

Description

The present invention relates to a spun yarn containing polyimide short fibers and a method for producing the same.

Conventionally, work clothes (tops and bottoms) used in places exposed to fire, high heat, etc. In addition to bottoms, gloves, socks, etc.) are used fabrics made of heat-resistant fibers such as aramid fibers.

In the above-mentioned various work clothes, flame resistance, flame retardancy, high strength, chemical resistance, fatigue resistance (fabric strength, tear strength retention property), heat resistance, etc. are required, so meta-aramid fiber, para-aramid fiber , blended yarns or spun yarns of these fibers and other fibers are used (see, for example, Patent Documents 1 and 2).

Polyimide fibers are known as fibers having excellent chemical resistance and heat resistance as well as aramid fibers as described above. Patent Document 3 describes a manufacturing method for obtaining polyimide multifilament, and describes that it can be used for various industrial materials such as electrical insulating materials, flameproof clothing, tire cords, and FRP.

Furthermore, in Patent Document 4, under severe conditions such as high temperature stress and acidic conditions, a laminate that is suitably used as a filter cloth that is excellent in all of heat resistance, chemical resistance, dimensional stability and strength , describes a laminate obtained by laminating a fabric made of polyimide multifilament yarn and a web made of polyimide staple.

Further improvement in performance can be expected by using polyimide fibers with excellent heat resistance, chemical resistance, etc. in work clothes used in situations where there is a great danger of being exposed to fire, high heat, etc. as described above. However, the polyimide fiber has a problem of poor flexibility due to its high rigidity.

For this reason, in various woven and knitted fabrics mainly used for clothing, the spun yarn can provide woven and knitted fabrics having a soft feel while making full use of the inherent heat resistance and chemical resistance of polyimide fibers. has not yet been developed.

JP-A-1-221537 JP-A-4-50340 JP-A-1-292120 JP-A-9-52308

A main object of the present invention is to provide a polyimide short fiber-containing spun yarn that uses a predetermined amount of polyimide short fibers and can be used to produce a woven or knitted fabric that has excellent heat resistance, chemical resistance, and abrasion resistance and has a soft feel. That's what it is.

In order to obtain the above woven and knitted fabrics, the present inventors studied knitting and weaving using spun yarns using polyimide short fibers (staple fibers). In particular, the inventors thought that the above object could be achieved by using a spun yarn containing a polyimide short fiber bundle having a polyimide short fiber content of 50% by mass or more.

In general, spun yarns include, for example, yarns obtained by spinning fibers such as cotton, wool, cotton, wool, hemp, etc., and short fibers such as polyester, polyamide, acrylic, etc. as chemical fibers are used together with the above yarns. spun yarns are widely used.

However, almost no spun yarn using polyimide short fibers has been proposed. The reason for this is that, unlike the above-mentioned chemical fibers, polyimide fibers have high rigidity and greatly differ in the amount of water and oil content, so polyimide short fibers are used instead of the short fibers used in the normal spinning process. It is presumed that this is because the desired spun yarn cannot be obtained even if the

Therefore, the present inventors reviewed the general spinning process, particularly in the following points. In the process of manufacturing spun yarn, a cotton blending machine is used to untangle raw cotton and at the same time remove dust adhering to the raw cotton to obtain a sheet-like "wrap". The sheet of wrap is then supplied to the carding process. In the carding process, a carding machine is used to card the wrap to separate the fibers one by one, align them parallel, and remove small debris and short fibers. The remaining long fibers are arranged parallel to some extent to form a web, which is bundled and pressed with a calender roll to obtain a string-like "card sliver".

Polyimide fibers have high rigidity and, as mentioned above, are different from chemical fibers such as polyesters and polyamides in terms of water content and oil content. When the batting process is performed, the obtained sheet-like wrap has poor uniformity. Furthermore, in the carding process, the lap is carded to separate the fibers one by one, and the web is drawn in a parallel state and spun. is not converged, and a curling phenomenon occurs. As a result, the web is not introduced into the calender rolls and no card sliver can be obtained. Moreover, even when the curling phenomenon is small and the web is introduced into the calender rolls, it is not possible to obtain a card sliver with a high degree of uniformity in which the fibers are aligned in parallel.

In the case of obtaining a spun yarn, after obtaining a card sliver, in the drawing process, 6 to 8 card sliver are combined and stretched 6 to 8 times using a drawing machine to straighten the fiber to a thickness. Obtains a 'Renjyo Sliver' that has no spots. In other words, in the drawing process, in order to obtain a roving with no unevenness in thickness in the next roving process, the drawing sliver should be drawn with a high degree of uniformity in which the fibers are aligned in parallel and drawn. is required. In this case, if a carded sliver with a low degree of uniformity is used, it is not possible to obtain a carded sliver with a high degree of uniformity, and consequently, it is impossible to obtain a roving yarn without unevenness in thickness.

Therefore, as a result of further studies, the inventors of the present invention have found that, particularly in the carding process, a short fiber raw material containing a predetermined amount of oil is used, and then the raw material is mixed and beaten to produce a card wrap. By performing carding while adjusting the amount of static electricity generated in the web spun after carding to ±0.2 kv or less, even if polyimide short fibers account for 50% by mass or more of the total mass, uniformity The inventors have found that a card sliver with a high yield can be obtained, and have completed the present invention.

That is, the present invention relates to the following spun yarn and method for producing the same.
1. A spun yarn containing polyimide short fibers,
(1) including a polyimide short fiber bundle having a polyimide short fiber content of 50% by mass or more,
(2) The content of polyimide short fibers in the spun yarn is 20% by mass or more.
A spun yarn characterized by:
2. 2. The spun yarn containing polyimide short fibers, having a core and a sheath in a cross section perpendicular to the longitudinal direction of the yarn, wherein the sheath is the polyimide short fiber bundle. spun yarn.
3. 1. The spun yarn containing polyimide short fibers, having a core and a sheath in a cross section perpendicular to the longitudinal direction of the yarn, wherein the core is the polyimide short fiber bundle. spun yarn.
4. 4. The spun yarn according to Item 3, wherein the sheath contains 50% by mass or more of cellulosic fibers.
5. 5. Any one of items 2 to 4 above, wherein the area ratio of the core portion and the sheath portion in a cross section perpendicular to the longitudinal direction of the yarn is core:sheath=80:20 to 20:80. spun yarn.
6. 6. The spun yarn according to any one of Items 1 to 5, which has a Worcester spot (U%) of 13% or less.
7. A woven or knitted fabric comprising the spun yarn according to any one of Items 1 to 6.
8. A method for producing a spun yarn, comprising the following steps (1) and (2):
(1) Using a short fiber raw material containing 100 parts by mass of polyimide short fibers and 0.05 to 0.3 parts by mass of an oil agent, a sheet-like wrap containing 50% by mass or more of polyimide short fibers is obtained by a mixed cotton process. and (2) when carding the sheet-shaped wrap, the card sliver is adjusted while adjusting the static electricity generation amount of the web obtained after the carding treatment within the range of -0.2 to +0.2 kv. A method for producing a spun yarn, comprising a step of obtaining a spun yarn.
9. Further, in the roving step (3), a plurality of drawn sliver obtained from the card sliver is used, and at least one drawn sliver is used as a sliver for the core portion, and the other drawn sliver is used as a sheath sliver for the core. 9. The manufacturing method according to item 8, comprising a step of obtaining a roving having a two-layer structure by spinning while winding it around a sliver for a part.

ADVANTAGE OF THE INVENTION According to this invention, the spun yarn which is excellent in heat resistance, chemical resistance, and wear resistance, and can produce the woven or knitted fabric with which a soft touch is required can be provided. In particular, since the spun yarn of the present invention contains a polyimide short fiber bundle having a polyimide short fiber content of 50% by mass or more, it has excellent heat resistance, chemical resistance, and abrasion resistance, which are inherent properties of polyimide fibers. In addition, it can impart a soft texture to the obtained woven or knitted fabric.

In addition, the spun yarn of the present invention has excellent heat resistance, chemical resistance and resistance, especially when it has a two-layer structure containing polyimide staple fibers in the core and cellulosic fibers in the sheath. It has abrasion resistance and the like, and can impart a soft texture and high dyeability to the resulting woven or knitted fabric.

For this reason, the woven or knitted fabric obtained from the spun yarn of the present invention is used in applications where there is a high risk of being exposed to flames or high heat, such as firefighting clothing, work clothing for iron or steel mills, work clothing for welding work, and the like. Suitable for working clothes, working gloves, etc.

1 is a schematic diagram showing one embodiment of a carding machine for obtaining the spun yarn of the present invention. FIG. 1 is a schematic view showing one embodiment of a roving machine for obtaining the spun yarn of the present invention having a core and a sheath; FIG. 1 is a schematic view showing one embodiment of a roving machine for obtaining the spun yarn of the present invention having a core and a sheath; FIG. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view including a cross-sectional configuration example of a two-layer structure spun yarn of the present invention; BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram of a cross-sectional configuration example of the spun yarn of the present invention;

41 Calender roller 42 Can 43 Doffer 44 Cylinder 45 Flat 46 Taker roller 47 Feed roller 48 Feed table 49 Wrap roller 51 Sliver 52 Web 53 Measuring position 54 Wrap A Back roller B Middle roller C Apron D Front roller E Flyer head F Flyer G Coarse Yarn S1 Core sliver S2 Sheath sliver

1. Spun yarn The spun yarn of the present invention is a spun yarn containing polyimide short fibers,
(1) A polyimide short fiber bundle having a polyimide short fiber content of 50% by mass or more (hereinafter sometimes simply referred to as "short fiber bundle P"),
(2) The content of polyimide short fibers in the spun yarn is 20% by mass or more.
It is characterized by

(A) Configuration of spun yarn The spun yarn of the present invention is not particularly limited in its form, structure, etc., as long as it contains the short fiber bundle P. For example, a single type (single layer type), or a double-layered spun yarn having a core-sheath structure in which the staple fiber bundle P forms a core or a sheath. In particular, a two-layer structure spun yarn is preferable in order to give a woven or knitted fabric properties suitable for use in clothing, such as soft texture, dyeability, and water absorbency, depending on the application.

A single-type spun yarn is a spun yarn substantially composed only of a short fiber bundle P having a polyimide short fiber content of 50% by mass or more. The spun yarn is a single layer (single phase) in a cross section perpendicular to the longitudinal direction of the yarn as shown in FIG. 5A.

In addition, in a single-type spun yarn, when the content of polyimide staple fibers in the staple fiber bundle P is 100% by mass, the spun yarn of the present invention is a spun yarn consisting essentially of polyimide staple fibers. . In addition, in a single-type spun yarn, when fibers other than polyimide staple fibers (hereinafter sometimes referred to as "second staple fibers") are included in the staple fiber bundle P, the polyimide staple fibers and the second short fibers are The spun yarn of the present invention is the blended yarn containing the fibers.

A two-layer structure spun yarn has a staple fiber bundle P as a core portion or a sheath portion, and has a core portion and a sheath portion in a cross section perpendicular to the longitudinal direction of the yarn. For example, there is a spun yarn 10 as shown in FIG. This spun yarn 10 is composed of a core portion 11 which is a staple fiber bundle P and a sheath portion 12 formed so as to cover the periphery thereof. FIG. 5C shows a schematic diagram of a cross section of the spun yarn 10 perpendicular to the longitudinal direction of the yarn. Also, the present invention may have a structure in which the core and the sheath are arranged opposite to that in FIG. 5C. The present invention also includes a spun yarn in which the short fiber bundle P is the sheath portion 12, as shown in the cross-sectional view of FIG. 5B, for example. As the two-layer structure spun yarn of the present invention, as shown in FIGS. 5B and 5C, the sheath portion 12 is a staple fiber bundle P (hereinafter sometimes referred to as “spun yarn A”); Two types of spun yarn are preferred, one in which the core portion 11 is a staple fiber bundle P (hereinafter sometimes referred to as “spun yarn B”).

The two-layer structure spun yarn of the present invention uses a plurality of drawn sliver with a high degree of uniformity obtained in the above-described drawing step, uses at least one drawing sliver as a core sliver in the roving step, and It is preferably obtained by a method including a step of obtaining a roving having a two-layer structure by winding the drawing sliver of (1) as a sheath sliver around a core sliver and spinning while forming a sheath. A detailed method for producing the two-layer structure spun yarn will be described later.

In the present invention, the content of polyimide short fibers in the spun yarn is 20% by mass or more, preferably 25% by mass or more. Therefore, for example, it can be set to 30% by mass or more, or can be set to 50% by mass or more. Thereby, the physical properties (heat resistance, chemical resistance, abrasion resistance, etc.) inherent in the polyimide short fibers can be more effectively exhibited. The upper limit of the above content can be, for example, about 90% by mass, but is not limited to this.

In the case of the two-layer structure spun yarn as described above, as long as the short fiber bundle P contains a predetermined amount of polyimide short fibers, the polyimide short fibers may be contained in both the core portion and the sheath portion. Alternatively, it may be contained only in the short fiber bundle P.

(B) Short fiber bundle P
The spun yarn of the present invention essentially contains the short fiber bundle P as described above. One or two or more short fiber bundles P may be included in the spun yarn of the present invention. In the present invention, one short fiber bundle P generally consists of one drawing sliver just before it is introduced into the roving machine. 5A to 5C, the number of short fiber bundles P is one.

The polyimide short fibers in the short fiber bundle P are not limited as long as they are handled as short fibers, but it is usually preferred that the fiber length is 20 to 80 mm. Further, the single fiber fineness is preferably in the range of 0.5 to 10.0 dtex, more preferably in the range of 0.8 to 3.0 dtex. If it is less than 0.5 dtex, the fiber itself may be inferior in strength. On the other hand, if the thickness exceeds 10.0 dtex and is excessively thick, the strength of the spun yarn tends to decrease due to less entanglement between fibers, and the quality of workability, texture, etc. in the post-process may be inferior. .

The polyimide short fibers contained in the short fiber bundle P preferably have a limiting oxygen index (LOI value) of 36 to 38, which is an index of heat resistance (flame retardancy).

The content of the polyimide short fibers contained in the short fiber bundle P is usually 50% by mass or more, preferably 60% by mass or more, and more preferably 70% by mass or more. The upper limit of the content can be, for example, 100% by mass, but is not limited to this. If the above content is less than 50% by mass, the original physical properties of the polyimide fiber may not be obtained.

When the content of polyimide short fibers is less than 100% by mass, short fibers other than polyimide short fibers (hereinafter, short fibers other than polyimide short fibers are also referred to as "second short fibers") are present in the short fiber bundle P. will be included. The second short fibers may be of one type or two or more types.

The second short fibers are not particularly limited as long as they do not interfere with the effects of the present invention, and may be synthetic fibers, semi-synthetic fibers or natural fibers. For example, at least one of polyamide fibers, polyester fibers, acrylic fibers, cellulose fibers, polyvinyl alcohol fibers, and the like can be preferably used. Among these, it is preferable to include cellulose fibers (short cellulose fibers) as the second short fibers from the standpoint of dyeability and texture. Moreover, it is preferable that the second short fibers have flame retardancy.

Cellulosic fibers are not particularly limited, and for example, natural cellulose fibers such as cotton and hemp, regenerated cellulose fibers such as viscose rayon and solvent-spun cellulose fibers, and modal fibers can be used. In particular, from the viewpoint of making a spun yarn excellent in flame retardancy and heat resistance, it is preferable to include flame-retardant cellulose fibers (flame-retardant cellulose fibers such as flame-retardant rayon fibers). Cellulose fibers having flame retardancy include, for example, regenerated cellulose fibers containing a flame retardant containing a phosphorus compound as a main component. This regenerated cellulose fiber can be easily obtained by applying the existing viscose method or the like. For example, if known wet spinning is performed by adding a flame retardant to the spinning solution, a regenerated cellulose fiber having flame retardancy can be easily obtained.

The cellulosic fiber is not limited as long as it is treated as short fiber, but it is usually preferred that the fiber length is 20 to 80 mm. The single fiber fineness is preferably in the range of 0.5 to 6.0 dtex, and more preferably in the range of 1.0 to 5.0 dtex. If it is less than 0.5 dtex, the fiber itself may be inferior in strength. On the other hand, if the thickness exceeds 6.0 dtex and the thickness is excessively large, entanglement between the fibers is reduced, so that the strength of the spun yarn tends to decrease, and the workability, texture, etc. in the post-process may deteriorate.

An embodiment in which the short fiber bundle P contains the second short fibers includes, for example, a composition in which the polyimide short fibers are 60 to 100 mass % and the second short fibers are 0 to 40 mass %. Furthermore, the proportion of cellulose fibers in the second short fibers can be, for example, about 90 to 100% by mass, but is not limited to this.

(C) Short fiber bundles other than the short fiber bundles P The spun yarn of the present invention contains the short fiber bundles P. In the case of the two-layer structure spun yarn as described above, staple fibers other than the short fiber bundles P are used. One type or two or more types of bundles (hereinafter also referred to as "short fiber bundles Q") are included.

As the type of fibers constituting the short fiber bundle Q, the same polyimide short fibers and second short fibers used in the short fiber bundle P can be used. It can be adopted as appropriate. In particular, in the spun yarn of the present invention, the short fiber bundle Q containing 50% by mass or more (preferably 60% by mass or more) of cellulosic fibers can be suitably used. This makes it possible to impart desired properties to the spun yarn more reliably.

An embodiment of the short fiber bundle Q includes, for example, a composition containing 60 to 100% by mass of the second short fibers and 0 to 40% by mass of the polyimide short fibers. In the present invention, the proportion of cellulose fibers in the second short fibers can be, for example, about 85 to 100% by mass, but is not limited to this.

(D) Properties of the spun yarn of the present invention The spun yarn of the present invention contains staple fiber bundles P. Then, even though the spun yarn has the staple fiber bundles P, by adopting the production method described later, it is possible to obtain a spun yarn that does not have unevenness in thickness (small Worcester spots (U%)). With such a spun yarn, the resulting woven or knitted fabric has a soft texture and improved quality, and can be used for a wide range of clothing applications. From this point of view, the spun yarn of the present invention preferably has a Worcester spot (U%) of 13% or less, more preferably 12% or less. The lower limit of the Worcester spots (U%) can be, for example, about 8%, but is not limited to this.

The spun yarn of the present invention preferably has a limiting oxygen index (LOI value) of 25 or more, more preferably 26 to 41, which is an index of heat resistance (flame retardancy).

Abrasion strength (measured according to the standard time of 9.10.1 A method of Japanese Industrial Standards JIS L1095 and indicated by the average number of reciprocating frictions) is preferably 350 or more. 9.10 Abrasion strength of JIS L1095 9.10.1 A method and A method are according to the following procedure. a) Standard time A metal cylinder with a diameter of 7.6 cm is wrapped with abrasive paper of Cw-C-P 1000 specified in JIS R 6253, and the sample prepared according to Clause 7 is subjected to 0.00265 N / tex as shown in Figure 5. Make contact with a load applied. Next, the metal cylinder is reciprocated over a distance of 10 cm at a reciprocating speed of 130 times/min, and the number of times of reciprocating friction until the sample is cut by abrasion is measured. The number of tests was 30, and the wear strength was expressed by rounding the average value and variation rate of the number of frictions to one decimal place. If the load is different, and if the load and the number of tests are increased, the number of tests shall be added to the test report.

<Embodiment of Spun Yarn>
The spun yarn of the present invention is particularly suitable for use in clothing, and in order to impart properties such as soft texture, dyeability, and water absorbency to woven and knitted fabrics, it is particularly necessary to use a two-layer structure spun yarn as described below. preferably. Therefore, the two-layer structure spun yarn (especially the above-mentioned spun yarns A and B) will be described more specifically as a preferred embodiment.

Spun yarn A
The spun yarn A, for example, as shown in FIG. 5B, is composed of a short fiber bundle P arranged as a sheath portion 12 and a short fiber bundle Q arranged as a core portion 11 in the space of the sheath portion 12. .

The sheath portion is a polyimide short fiber bundle (short fiber bundle P) having a polyimide short fiber content of 50% by mass or more. Among them, the short fiber bundle P of the sheath preferably contains 60% by mass or more of polyimide short fibers, more preferably 70% by mass or more of polyimide short fibers.

As the second short fibers other than the polyimide short fibers contained in the sheath, those having excellent heat resistance, chemical resistance, abrasion resistance, etc. are preferable. Examples thereof include flame-retardant rayon fiber, flame-retardant modal fiber, flame-retardant vinylon fiber, flame-retardant polyester fiber, flame-retardant acrylic fiber, and aramid fiber. A plurality of types of these fibers may be contained. They can also be used as the second short fibers of the core.

The core portion is a short fiber bundle Q containing 60% by mass or more of the second short fibers. The second short fibers preferably contain cellulose fibers. Cellulosic fibers are preferably contained in the core in an amount of 60% by mass or more.

The second staple fibers other than the cellulosic fibers contained in the core are preferably those that do not interfere with the mechanical properties of the two-layer structure spun yarn and the effect of imparting a soft texture by the cellulosic fibers, such as acrylic fibers and polyesters. Fibers and the like can be used.

The content of polyimide short fibers in the entire spun yarn A is preferably 20% by mass or more, more preferably 25% by mass or more.

The content of the second staple fibers in the entire spun yarn A is preferably 20 to 80% by mass, more preferably 25 to 75% by mass.

When the content of the second staple fibers constituting the spun yarn A is less than 20% by mass, or when the proportion of the second staple fibers in the core is less than 50% by mass, the properties of the second staple fibers are difficult to give. The second short fibers in the core preferably contain cellulose fibers as described above, and the proportion of the cellulose fibers in the core is 60% by mass or more, especially 80% by mass or more, and further 90% by mass or more. Preferably. The use of cellulosic fibers as the second short fibers makes it possible to impart a soft texture or water absorbency to the resulting woven or knitted fabric, and can be suitably used for clothing.

As such a two-layer structure spun yarn, for example, a draw sliver containing 50% by mass or more of polyimide short fibers is used as the sheath sliver, and 50% by mass or more (especially 60% by mass) of cellulosic fiber is used as the core sliver. % or more) is preferably used to form a two-layer structure spun yarn.

By configuring the spun yarn A as described above, a large amount of polyimide short fibers are exposed on the surface of the fiber, so that the spun yarn A is excellent in heat resistance, chemical resistance, abrasion resistance, and the like. Since the second short fibers are contained in a relatively large amount in the core portion, the fiber can have the performance of the second short fibers. For example, in the case of cellulosic fibers, they are excellent in softness and water absorbency.

The spun yarn A preferably has a limiting oxygen index (LOI value) of 36 or more, more preferably 37 or more, which is an index of heat resistance (flame resistance). In addition, the abrasion strength (measured according to the standard time of 9.10.1 A method of JIS L1095, indicated by the average value of the number of reciprocating abrasions) is preferably 3000 or more, and more preferably 3500 or more. .

In the spun yarn A, the area ratio of the core to the sheath in the cross section perpendicular to the longitudinal direction of the yarn is preferably core:sheath=80:20 to 20:80, especially core:sheath. Part=60:40 to 20:80 is preferred.

The area ratio of the core portion to the sheath portion in the two-layer structure spun yarn of the present invention can be determined by photographing a cross section perpendicular to the longitudinal direction of the two-layer structure spun yarn with an optical microscope. area ratio can be measured.

As an example of an embodiment of the composition of the spun yarn A, the core portion is composed of 0 to 40% by mass of polyimide staple fibers, the composition is 60 to 100% by mass of second staple fibers, and the sheath portion is composed of 90% polyimide staple fibers. to 100% by mass, and the second short fibers are 0 to 10% by mass. In this case, as an example of the composition of the second short fibers, the cellulose fiber is 90 to 100% by mass, and at least one of acrylic fiber, polyester fiber, polyvinyl alcohol fiber, etc. is 0 to 10% by mass. can.

Spun Yarn B
The spun yarn B, for example, as shown in FIG. 5C, is composed of a short fiber bundle Q arranged as a sheath portion 12 and a short fiber bundle P arranged as a core portion 11 in the space of the sheath portion 12. .

The spun yarn B is a polyimide short fiber bundle (short fiber bundle P) in which the core portion contains 50% by mass or more of polyimide short fibers. Among them, the short fiber bundle P of the core preferably contains 60% by mass or more of polyimide short fibers, more preferably 70% by mass or more of polyimide short fibers.

As the second staple fibers contained in the core, those having excellent heat resistance, chemical resistance, wear resistance, etc. are preferable. At least one of flame-retardant acrylic fiber and the like is included. They can also be used as secondary staple fibers in the sheath.

Moreover, the second staple fibers contained in the core preferably contain the same type of fibers as the second staple fibers contained in the sheath.

The sheath is a short fiber bundle Q containing 60 mass % or more (preferably 80 mass % or more, more preferably 90 to 100 mass % or more) of the second short fibers.

As the second staple fibers contained in the sheath, it is preferable to use cellulosic fibers, preferably containing 50% by mass or more of cellulosic fibers in the sheath, more preferably containing 60% by mass or more, and furthermore The one containing 90% by mass or more is most preferable. Therefore, the content can be set to 90 to 100% by mass. In particular, by using cellulosic fibers as the second staple fibers, it is possible to impart a soft texture or water absorbency to the resulting woven or knitted fabric, which can be suitably used for clothing.

As the second staple fibers of the sheath, it is preferable to contain cellulosic fibers as described above. It is preferably used within a range that does not interfere with the effect of imparting soft texture or dyeability. For example, at least one of acrylic fiber, polyester fiber, vinylon fiber and the like can be preferably used.

The content of the polyimide short fibers in the entire spun yarn B is generally preferably 20% by mass or more, more preferably 25% by mass or more.

Furthermore, the content of the second staple fibers in the entire spun yarn B is generally preferably 20 to 80% by mass, more preferably 25 to 75% by mass.

When the content of the second staple fibers constituting the spun yarn B is less than 20% by mass, or when the ratio of the second staple fibers in the sheath is less than 60% by mass, the second staple fibers are placed on the fiber surface The characteristics (e.g., soft texture, dyeability, water absorbency, etc.) that can be obtained by using it cannot be sufficiently imparted, and it may be difficult to use it widely, especially for general clothing applications.

As such a two-layer structure spun yarn, a draw sliver containing 50% by mass or more (particularly 60% by mass or more) of cellulosic fibers is used as the sheath sliver, and 50% by mass of polyimide staple fiber is used as the core sliver. % or more is preferably used to form a two-layer structure spun yarn.

By configuring the spun yarn B as described above, the short polyimide fibers are not exposed on the surface of the fiber, so that the spun yarn B has a heat resistance while covering the poor rigidity or dyeability of the polyimide fiber. It is possible to impart excellent properties such as toughness, chemical resistance, and abrasion resistance. In particular, by containing 50% by mass or more of cellulosic fibers in the sheath, the spun yarn can be made excellent in dyeability or soft texture.

The spun yarn B preferably has a limiting oxygen index (LOI value) of 26 or more, which is an index of heat resistance (flame retardancy), as the characteristic value as described above. In addition, the abrasion strength (measured according to the standard time of 9.10.1 A method of JIS L1095, expressed as the average value of the number of reciprocating abrasions) is preferably 350 or more, more preferably 450 or more. .

In the spun yarn B, the area ratio of the core to the sheath in the cross section perpendicular to the longitudinal direction of the yarn is preferably core:sheath=80:20 to 20:80, especially core:sheath. Part=60:40 to 30:70 is more preferred. This area ratio can be measured in the same manner as the method described for the spun yarn A.

As an example of an embodiment of the composition of the spun yarn B, the core portion is composed of 60 to 80% by mass of polyimide staple fibers, the second staple fibers are of 20 to 40% by mass, and the sheath portion is composed of polyimide staple fibers. 0 to 10% by mass, and those having a composition of 90 to 100% by mass of the second short fibers. In this case, as an example of the composition of the second short fibers, the cellulose fiber is 90 to 100% by mass, and at least one of acrylic fiber, polyester fiber, polyvinyl alcohol fiber, etc. is 0 to 10% by mass. can.

As described above, the two-layer structure spun yarn of the present invention uses at least one drawn sliver as a core sliver, and another drawn sliver as a sheath sliver is spun while being wound around the core sliver. It is preferable to obtain a roving having a two-layer structure having a core portion and a sheath portion by a method including a step of extracting. In this case, in the above process, a two-layer structure spun yarn having a plurality of core portions can be obtained. That is, the two-layer structure spun yarn of the present invention may have two or more core portions.

A two-layer structure spun yarn having one core (short fiber bundle P or short fiber bundle Q) can be produced by using the apparatus shown in FIGS. For example, in order to manufacture a product having 2 to 4 cores, 2 to 4 drawn sliver forming the core are supplied, and the drawn sliver forming the sheath is wound. .

2. Method for producing spun yarn The spun yarn of the present invention is produced by, for example, the following steps (1) and (2):
(1) Using a short fiber raw material containing 100 parts by mass of polyimide short fibers and 0.05 to 0.3 parts by mass of an oil agent, a sheet-like wrap containing 50% by mass or more of polyimide short fibers is obtained by a mixed cotton process. and (2) when carding the sheet-shaped wrap, the amount of static electricity generated in the web obtained after the carding is within the range of -0.2 to +0.2 kv. The process of obtaining card sliver while adjusting (carding process)
It can be suitably produced by a method for producing a spun yarn characterized by comprising

In the cotton blending process, a short fiber raw material containing 100 parts by mass of polyimide short fibers and 0.05 to 0.3 parts by mass of an oil agent is used, and a sheet-like material containing 50% by mass or more of polyimide staple fibers is produced by the cotton blending process. get a rap

In the blending process, a short fiber raw material containing 100 parts by mass of polyimide short fibers and 0.05 to 0.3 parts by mass of an oil agent is used. That is, a sheet-like wrap is obtained by using surface-treated polyimide short fibers obtained by applying an oil agent to the surface of the fiber by controlling the type and amount of the oil agent as a short fiber raw material (starting material). Then, in the carding process, the carding process is carried out while adjusting the static electricity generation amount of the web spun from the carding machine to ±0.2 kv or less by adjusting the ambient temperature, humidity, etc. near the carding process, and the card sliver. obtain.

As the oil, commercially available textile oils for spinning can be used, and textile oils used for spinning synthetic fibers are particularly preferred. Among them, surfactants are preferably used, and nonionic surfactants are more preferably used. The nonionic surfactant may be of an ester type, an ether type, an ester/ether type, or the like. In particular, in the present invention, ether type (especially polyoxyethylene/alkyl ether) is preferred. A commercially available product can also be used as such a surfactant. For example, "Marpoteron LE" manufactured by Matsumoto Yushi Seiyaku Co., Ltd. can be preferably used.

The oil agent is preferably added in an amount of 0.05 to 0.3% by mass, more preferably 0.08 to 0.2% by mass, based on the fiber mass of the polyimide short fibers. By setting it within this range, the amount of static electricity generated on the web in the carding process can be controlled more reliably.

The method of applying the oil agent to the polyimide short fibers is not particularly limited. For example, a diluted solution is prepared by diluting the oil agent to a concentration of about 1.0 to 5.0%, and it is sprayed on the fiber surface of the raw cotton of the polyimide short fibers. A method of refueling by spraying uniformly can be preferably adopted. The timing of applying the oil agent to the polyimide short fibers is not particularly limited, but it is desirable to apply the oil agent at least before the cotton blend treatment.

The conditions for the cotton blending treatment are not particularly limited as long as a sheet-like wrap can be obtained by unraveling the polyimide short fibers that are the raw cotton. can also be carried out within the scope of

In the carding step, carded sliver is obtained while adjusting the amount of static electricity generated in the web obtained after the carding process within the range of -0.2 to +0.2 kv when carding the sheet-like wrap. That is, the carding process is carried out so that the amount of electricity generated in the web obtained in the carding process is within the range of -0.2 to +0.2 kv. One of the particularly important steps in the method for producing the spun yarn of the present invention is the carding step in which sliver is obtained from the lap obtained by the cotton blending machine.

In the present invention, it is necessary to obtain a card sliver containing 50% by mass or more of short polyimide fibers. As a result of various investigations while considering the characteristics of polyimide fibers, the carding process was carried out while adjusting the amount of static electricity generated in the web spun after being carded by a carding machine to ±0.2 kv or less. It was found that a card sliver with a high degree of uniformity can be obtained even when the polyimide short fibers in the short fiber bundle P account for 50% by mass or more.

Here, the carding process will be described with reference to FIG. First, polyimide short fibers, which are raw cotton, are unraveled using a cotton blending machine, and at the same time, dust adhering to the raw cotton is removed to obtain a sheet-like wrap 54 . The wrap is passed through a plurality of rollers and introduced into the card machine. Even when polyimide short fibers and second short fibers are used as raw cotton, the same procedure is performed.

Next, the wrap is carded in a carding machine to separate the fibers one by one, and the fibers are aligned in parallel to form a web. It is then collected and introduced into calender rolls. The amount of static electricity generated on the web 52 at this time is preferably measured at the measurement position 53 shown in FIG.

The amount of static electricity generated in the web spun from the carding machine is measured directly above the web (25 mm above the web) using Simco-Ion static electricity meter ELECTROSTATIC FIELDMETER FMX-003 manufactured by Simco Japan.

If the amount of static electricity generated is outside the above range, the web spun after carding the wrap in the carding process will curl up and cannot be introduced into the calender rolls. Moreover, even if it can be introduced into a calender roll, it is not possible to obtain a cord-like card sliver with a high degree of uniformity.

In order to keep the amount of static electricity generated in the web spun from the carding machine within the above range, it is possible to control the amount of static electricity generated in the web by, for example, adjusting the ambient temperature or humidity near the carding process. is. In particular, the atmospheric temperature is preferably within the range of 15 to 45°C. Also, the humidity is preferably within the range of 45 to 75%.

In addition, as described above, by using polyimide short fibers to which 0.05 to 0.3% by mass of oil is applied with respect to the fiber mass as polyimide short fibers to be supplied to the cotton blending process, It becomes possible to more reliably control the amount of static electricity generated on the web.

In this way, for example, by adjusting the amount of oil applied to the polyimide short fibers in the cotton blending process, the amount of static electricity generated in the web in the carding process, etc. to appropriate values, the fibers are arranged in a parallel state one by one. A curd sliver with a high degree of uniformity can be obtained.

Furthermore, in order to obtain high-quality spun yarn without unevenness in thickness, finer and shorter fibers are removed from the carded sliver after the carding process, and the fibers are made parallel by combing them. It is preferable to pass through the combing process to do. The combing process is performed using a combing machine, and can further improve the parallelism and uniformity of the fibers in the sliver. This makes it possible to obtain a spun yarn with less unevenness in thickness and higher quality.

In the above production method, a method for obtaining a sliver containing 50% by mass or more of polyimide short fibers is shown, but 50% by mass or more (especially 60% by mass or more) of second fibers (cellulosic fibers, etc.) When obtaining sliver, it can also be produced by a known method.

The carded sliver obtained above can be drawn in a drawn step by drawing a plurality of carded sliver together to obtain a carded sliver with no unevenness in thickness. As a result, it is possible to obtain a high-quality spun yarn with no unevenness in thickness. The drawing step can be carried out according to the conditions and the like in a known drawing step.

In the case of producing a two-layer structure spun yarn using the drawn sliver obtained as described above, a plurality of drawn sliver are further used, and at least one drawn sliver is used as the core sliver, and the other A step of obtaining a roving having a two-layer structure (roving step) is performed by spinning a drawing sliver as a sheath sliver while winding it around the core sliver.

More specifically, after obtaining a drawing sliver (sliver S1) containing 50% by mass or more of the polyimide short fibers and a drawing sliver (sliver S2) containing 50% by mass or more of the second fibers, respectively, manufacturing method example 1 The two-layer structure spun yarn of the present invention (spun yarn A is exemplified) can be obtained.

Production method example 1: Sliver S1 and sliver S2 are prepared, sliver S1 is used as a core, sliver S2 is wound around sliver S1 to form a sheath, and then roving is performed. A double-layered spun yarn can be obtained.

The two-layer structure spun yarn of the present invention (spun yarn A is exemplified) can also be obtained by Production Method Example 2 shown below.

Production method example 2: After supplying sliver S1 and sliver S2 to a roving machine to form rovings (roving S1 and roving S2), the roving S1 is used as the core, and the roving S2 is wound around the roving S1. The two-layer structure spun yarn of the present invention can be obtained by spinning so as to form a sheath.

A method for producing the spun yarn A according to Production Method Example 1 will be described below with reference to the drawings. 2 (schematic diagram) and FIG. 3 (schematic diagram) are used to supply sliver S1 and sliver S2 as shown in FIG. is 60°, the sliver S2 is wound around the sliver S1, and the sliver S2 is wound while giving a false twisting effect by a flyer, so that the sliver S1 is the core and the sliver S2 is the sheath. thread) can be formed.

When the spun yarn B is produced by Production Method Example 1, the sliver S1 and the sliver S2 are exchanged and supplied, so that the sliver S2 is the core portion and the sliver S1 is the sheath portion. A two-layer structure yarn (roving). can be formed. At this point, the yarn is twisted for the first time and the roving is wound around the bobbin.

Although the number of twists in these roving processes is not limited, it is preferable to set the number so as not to cause poor drawing in the subsequent spinning process. For example, the twist coefficient can be adjusted to about 0.4 to 1.5. Here, it is preferable to adjust the mass ratio of the sliver to be the core and the sliver to be the sheath so that (core): (sheath) = 20:80 to 80:20. It is preferable to set the distribution in consideration of various factors such as specific gravity, strength, and crimp.

The roving produced in the roving process can be further subjected to the spinning process. In this step, the roving is stretched while being twisted to obtain a spun yarn having a predetermined strength.

The number of twists in the spinning process is not particularly limited, but from the viewpoint of physical properties (strength, fluff, etc.) or texture, the twist coefficient K is preferably in the range of 3.0 to 6.0, particularly 3.4. It is more preferably within the range of ~5.0. A loose twist such that the twist coefficient K is less than 3.0 may cause the yarn to come loose, or deteriorate the physical properties (especially pilling) of a woven or knitted product. Conversely, if the twist coefficient K is increased, a certain increase in strength and crispness can be achieved, but if it exceeds 6.0, defects such as deterioration of productivity, hardening of texture, defective seams, and snares will occur. It can be easy to connect.

The twist coefficient K is obtained by the following formula.
Twist factor (K) = Number of twists (number of times/2.54 cm)/√ (British cotton count)

3. Woven or Knitted Fabric The woven or knitted fabric of the present invention contains the spun yarn of the present invention as described above. The content of the spun yarn of the present invention in the woven or knitted fabric of the present invention is preferably 60% by mass or more, and is preferably 80% by mass or more when heat resistance, chemical resistance, abrasion resistance, etc. are more important. More preferably, it is most preferably 100% by mass.

In addition, when the woven or knitted fabric of the present invention is used for applications requiring high heat resistance, chemical resistance, abrasion resistance, etc., polyimide short fibers are used in the sheath so that the polyimide short fibers are on the fiber surface. It is preferable to use a two-layer structure spun yarn (spun yarn A) in which On the other hand, when emphasizing soft texture or dyeability, use a two-layer structure spun yarn (spun yarn B) in which a polyimide fiber is arranged in the core and the second short fibers are arranged on the surface of the fiber. is preferred.

Then, the structure, basis weight, etc. of the woven or knitted fabric may be appropriately selected according to the purpose of use, application, and the like.

Plain weave, gauze weave (twill), double weave, ripstop, and the like are preferred for textiles in which heat resistance, chemical resistance, abrasion resistance, etc. are important. These fabrics have little thread floating, are difficult to ventilate, and can prevent the passage of heat or flame. Too light (too thin) results in poor performance, and too heavy (too thick) impairs comfort.

Therefore, although the basis weight of the woven or knitted fabric of the present invention is not limited, it is usually preferably in the range of 100 to 500 g/m ² . Also, for flameproof clothing, the range of 250 to 350 g/m ² is particularly preferred.

In addition, as the spun yarn of the present invention, the fabric obtained by using at least one of the single-type spun yarn and the spun yarn A for the warp and weft has excellent heat resistance. It has excellent transmission performance and excellent abrasion strength.

The spun yarn or woven or knitted fabric of the present invention may be subjected to various treatments (for example, calendering, raising, water absorption, water repellency, antistatic, shrink-proof, antibacterial, deodorant processing, etc.) may be applied.

EXAMPLES The present invention will be described in more detail below with reference to examples and comparative examples. In addition, the measuring method or evaluation method of each physical property is as follows.

[Characteristic values of spun yarn]
<Limited oxygen index (LOI value)>
Using the obtained spun yarn, it was measured according to E method of JIS L1091.
<Abrasion strength>
Using the obtained spun yarn, the initial load was set to 11 g according to the standard time of 9.10.1 A method of JIS L1095, and the abrasive paper P1000 was used for measurement. The number of tests was 30, and the wear strength is indicated by the average value of the number of times of friction.
<Worcester spots (U%)>
Keisokki's EVENNESS TESTER (MODEL: KET-80 V/B) is used to express the degree of uniformity of the spun yarn, and the thickness variation of the obtained spun yarn is expressed as U% (mass per unit length of yarn). mean standard deviation). The smaller the U% value, the more even the spun yarn is, the less thick and thin the yarn is, and the higher the quality of the woven or knitted fabric can be obtained.

[Textile Characteristic Values and Evaluation]
<Combustibility>
Using the obtained woven fabric, afterflame time, afterflame time and combustion length were evaluated according to A-4 method of JIS L1091.
<Heat transferability>
Using the obtained woven fabric, a test piece is fixed to a free-standing frame (test piece holder) and exposed to a certain level of radiant heat according to JIS T8020, Method B. Evaluation was made by the time (t12) required for the temperature of the calorimeter to rise by 12°C and the time (t24) required for the temperature to rise by 24°C.
<Abrasion Strength>
Using the obtained woven fabric, evaluation was made by the number of times until the fabric was broken at a pressing load of 4.45 N according to JIS L 1096:2010 A method (universal type method) A-1 method (flat method).
<Hand Feel> Using the obtained woven fabric, the presence or absence of a soft feel was evaluated by panelists according to the following 3-grade scale.
◯: It has a smooth touch and excellent softness that can be used for clothing.
Δ: Although it has softness, it has a stiff feeling.
×: It does not have softness and is unsuitable for use in clothing.
<Dyeability>
Using the woven fabrics obtained in Examples and Comparative Examples, visual evaluation was performed by panelists according to the following two grades.
◯; dyed in a desired color.
×; Not dyed to desired color (light color).

[Fiber used]
Fibers used in the following examples and comparative examples are shown below.
(a) Polyimide staple fiber; JIANGSU AOSHEN HI-TECH NEW MATERIALS CO., LTD. LTD, 1.67dtex x 38mm, LOI value 38
(b) Flame-retardant rayon fiber; "NEXT-FR" manufactured by Omikenshi Co., Ltd., 1.40 dtex x 38 mm, LOI value 29
(c) Flame-retardant vinylon fiber; "T18" manufactured by Kuraray Co., Ltd., 1.70 dtex x 38 mm, LOI value 32
(d) Flame-retardant acrylic fiber; manufactured by KANEKA, 1.70 dtex x 38 mm, LOI value 32
(e) Aramid fiber; meta-aramid fiber manufactured by Kermel, 1.70 dtex × 51 mm, LOI value 33

Example 1
(sliver S1)
A mixture of 62.5% by mass of polyimide short fibers and 37.5% by mass of flame-retardant rayon fibers was put into a cotton blending machine to obtain a sheet-like wrap. At this time, 0.1% by mass of a polyoxyethylene/alkyl ether-based nonionic surfactant "Marpoteron LE" (manufactured by Matsumoto Yushi Seiyaku Co., Ltd.) was added as an oil to the polyimide short fibers before being put into the cotton blending machine. It was applied so that the amount of adhesion would be .
Then, the ambient temperature and humidity near the carding process are maintained at 25-27°C and 58-60% humidity, and the wrap obtained in the mixed cotton process is put into the carding machine as shown in Fig. 1, and the inside of the carding machine is After the carding process, the web was spun. At this time, the amount of static electricity generated in the web spun from the carding machine was -0.05 to -0.01 kv.
The web spun from the carding machine was well bundled and pressed by calender rolls to obtain a highly uniform carded sliver.
Next, the card sliver was introduced into a combing machine, and finer and shorter fibers were removed from the card sliver, and a combing process was performed to increase the parallelism and uniformity of the fibers.
Eight combed slivers thus obtained were combined in the drawing step and stretched 8.94 times to obtain sliver S1.
(sliver S2)
Using only flame-retardant rayon fibers, a sliver S2 was obtained through a cotton blending process, a carding process, and a drawing process.
A sliver S1 was prepared as a core sliver, and a sliver S2 was prepared as a sheath sliver.
A core sliver S1 and a sheath sliver S2 are supplied using a roving machine having a structure shown in FIG. 1 (schematic cross-sectional view) and FIG. : S2 = 40: 60, and the advancing angle θ of the core sliver S1 to the flyer head with respect to the draft direction in Fig. 2 is 60 °, and the roving mass is 240 gr / 30 yd (1 gr = 0.65 g, 1 yd = 0.9144 m) and a twist number of 0.977 times/2.54 cm.
This roving yarn is passed through the trumpet (guide) of the spinning machine, passed through the back roller, the apron, and the front roller in that order, and after being drawn 30.95 times, it is twisted 20.8 times / 2.54 cm in the Z direction. was twisted to obtain a two-layer structure spun yarn (spun yarn B) of 30 count (British cotton count). Two of these yarns were combined and twisted 16 times/2.54 cm in the S direction to obtain a two-ply yarn of a two-layer structure spun yarn (30/2 count).
Using the two-ply yarn of this two-layer structure spun yarn, a 2/1 right twill green fabric having a warp density of 67/2.54 cm and a weft density of 66/2.54 cm was obtained by an air jet loom. After desizing under the following desizing conditions, a woven fabric was produced by reactive dyeing under the following dyeing conditions.
(Desizing conditions)
Using 5 g/L of Biotex and 1 g/L of Sunmol FL as enzymatic desizing, the bath ratio was 1:50, and the conditions were 60° C. for 90 minutes.
(Staining conditions)
20 g/L of mirabilite and 30 g/Lm of caustic soda were added to the reactive dye "Remazol Brill B Blue 3% (owf)", and the fabric after desizing was immersed therein and dyed at 60° C. for 60 minutes. Then, after soaping (using "Lipotol RK-5" 1 g / L, performed under the conditions of 90 ° C. x 10 minutes), fixing (using Chelcut CF-2 2% (owf), 60 ° C. x 10 minutes (implemented under the following conditions). Next, 0.5% by mass of "RIKEN RESIN M-3", 0.05% by mass of ACX (catalyst), and the remainder as water were added, and the mixture was treated with a tenter at 175°C for 90 seconds to finish.

Example 2
(sliver S1)
80% by mass of polyimide short fibers and 20% by mass of flame-retardant rayon fibers were mixed and put into a cotton blending machine to obtain a sheet-like wrap. At this time, the short polyimide fibers to be fed into the cotton blending machine were pre-applied with the same oil solution as in Example 1 at a rate of 0.2% by mass with respect to the total amount of the fibers.
Then, the carding process, combing process, and drawing process were performed under the same conditions as in Example 1 to obtain sliver S1. At this time, the amount of static electricity generated in the web spun from the carding machine was -0.05 to -0.01 kv.
(sliver S2)
The same one as in Example 1 was used.
A sliver S1 was prepared as a core sliver, and a sliver S2 was prepared as a sheath sliver. Spinning was carried out in the same manner as in Example 1 to obtain a 30-count (British cotton count) two-layer structure spun yarn (spun yarn B). Two of these yarns were combined and twisted 16 times/2.54 cm in the S direction to obtain a two-ply yarn of a two-layer structure spun yarn (30/2 count). A woven fabric was obtained in the same manner as in Example 1, except that the obtained two-ply yarn was used.

Example 3
(sliver S1)
62.5% by mass of polyimide fiber and 37.5% by mass of flame-retardant rayon fiber were mixed, and put into a cotton blending machine to obtain a sheet-like wrap. At this time, the polyimide short fibers to be fed into the cotton blending machine were pre-applied with the same oil solution as in Example 1 at a rate of 0.05% by mass with respect to the total amount of the fibers. Then, the carding process, combing process, and drawing process were performed under the same conditions as in Example 1 to obtain sliver S1. At this time, the amount of static electricity generated in the web spun from the carding machine was -0.20 to -0.10 kv.
(sliver S2)
The same one as in Example 1 was used.
A sliver S1 was prepared as a core sliver, and a sliver S2 was prepared as a sheath sliver. Spinning was carried out in the same manner as in Example 1 to obtain a 30-count (British cotton count) two-layer structure spun yarn (spun yarn B). Two of these yarns were combined and twisted 16 times/2.54 cm in the S direction to obtain a two-ply yarn of a two-layer structure spun yarn (30/2 count). A woven fabric was obtained in the same manner as in Example 1, except that the obtained two-ply yarn was used.

Example 4
(sliver S1)
A mixture of 62.5% by mass of polyimide fiber and 37.5% by mass of flame-retardant vinylon fiber was put into a cotton blending machine to obtain a sheet-like wrap. At this time, the short polyimide fibers to be fed into the cotton blending machine were pre-applied with the same oil solution as in Example 1 at a rate of 0.1% by mass with respect to the total amount of the fibers.
Then, the carding process, combing process, and drawing process were performed under the same conditions as in Example 1 to obtain sliver S1. At this time, the amount of static electricity generated in the web spun from the carding machine was -0.05 to -0.01 kv.
(sliver S2)
Using only flame-retardant vinylon fibers, a sliver S2 was obtained through a cotton blending process, a carding process, and a drawing process.
A sliver S1 was prepared as a core sliver, and a sliver S2 was prepared as a sheath sliver.
A core sliver S1 and a sheath sliver S2 are supplied using a roving machine having a structure shown in FIG. 1 (schematic cross-sectional view) and FIG. : S2 = 40: 60, and the advancing angle θ of the core sliver S1 to the flyer head with respect to the draft direction in Fig. 2 is 60 °, and the roving mass is 240 gr / 30 yd (1 gr = 0.65 g, 1 yd = 0.9144 m ) to obtain a roving with a twist number of 0.758 turns/2.54 cm. Spinning was carried out under the same conditions as in Example 1, except that this roving was used, to obtain a 30-count (British cotton count) two-layer structure spun yarn (spun yarn B). Two of these yarns were combined and twisted 16 times/2.54 cm in the S direction to obtain a two-ply yarn of a two-layer structure spun yarn (30/2 count). A woven fabric was obtained in the same manner as in Example 1, except that the obtained two-ply yarn was used.

Example 5
(sliver S1)
A mixture of 62.5% by mass of polyimide fiber and 37.5% by mass of flame-retardant acrylic fiber was put into a cotton blending machine to obtain a sheet-like wrap. At this time, the short polyimide fibers to be fed into the cotton blending machine were pre-applied with the same oil solution as in Example 1 at a rate of 0.2% by mass with respect to the total amount of the fibers. Then, the carding process, combing process, and drawing process were performed under the same conditions as in Example 1 to obtain sliver S1. At this time, the amount of static electricity generated in the web spun from the carding machine was -0.10 to -0.05 kv.
(sliver S2)
Using only the flame-retardant acrylic fiber, a sliver S2 was obtained through a cotton blending process, a carding process, and a drawing process.
A sliver S1 was prepared as a core sliver, and a sliver S2 was prepared as a sheath sliver.
A core sliver S1 and a sheath sliver S2 are supplied using a roving machine having a structure shown in FIG. 1 (schematic cross-sectional view) and FIG. : S2 = 40: 60, and the advancing angle θ of the core sliver S1 to the flyer head with respect to the draft direction in Fig. 2 is 60 °, and the roving mass is 240 gr / 30 yd (1 gr = 0.65 g, 1 yd = 0.9144 m ) to obtain a roving with a twist number of 0.709 turns/2.54 cm. Spinning was carried out under the same conditions as in Example 1, except that this roving was used, to obtain a 30-count (British cotton count) two-layer structure spun yarn (spun yarn B). Two of these yarns were combined and twisted 16 times/2.54 cm in the S direction to obtain a two-ply yarn of a two-layer structure spun yarn (30/2 count). A woven fabric was obtained in the same manner as in Example 1, except that the obtained two-ply yarn was used.

Example 6
(sliver S1)
37.5% by mass of polyimide fiber and 62.5% by mass of flame-retardant rayon fiber were mixed and put into a cotton blending machine to obtain a sheet-like wrap. At this time, the short polyimide fibers to be fed into the cotton blending machine were pre-applied with the same oil solution as in Example 1 at a rate of 0.1% by mass with respect to the total amount of the fibers.
Then, the carding process, combing process, and drawing process were performed under the same conditions as in Example 1 to obtain sliver S1. At this time, the amount of static electricity generated in the web spun from the carding machine was -0.05 to -0.01 kv.
(sliver S2)
A sheet-like wrap was obtained by using 100% by mass of polyimide fiber and putting it into a cotton blending machine. At this time, the short polyimide fibers to be fed into the cotton blending machine were pre-applied with the same oil solution as in Example 1 at a rate of 0.2% by mass with respect to the total amount of the fibers.
Then, the carding process, the combing process, and the drawing process were performed under the same conditions as in Example 1 to obtain a sliver S2. At this time, the amount of static electricity generated in the web spun from the carding machine was 0 kv.
A sliver S1 was prepared as a core sliver, and a sliver S2 was prepared as a sheath sliver.
A core sliver S1 and a sheath sliver S2 are supplied using a roving machine having a structure shown in FIG. 1 (schematic cross-sectional view) and FIG. : S2 = 40: 60, and the advancing angle θ of the core sliver S1 to the flyer head with respect to the draft direction in Fig. 2 is 60 °, and the roving mass is 240 gr / 30 yd (1 gr = 0.65 g, 1 yd = 0.9144 m ) to obtain a roving with a twist number of 0.659 turns/2.54 cm. Spinning was carried out under the same conditions as in Example 1, except that this roving was used, to obtain a 30-count (British cotton count) two-layer structure spun yarn (spun yarn A). Two of these yarns were combined and twisted 16 times/2.54 cm in the S direction to obtain a two-ply yarn of a two-layer structure spun yarn (30/2 count). A woven fabric was obtained in the same manner as in Example 1, except that the obtained two-ply yarn was used.

Example 7
(sliver S1)
The sliver S2 (100% flame-retardant rayon fiber) used in Example 1 was used.
(sliver S2)
The sliver S2 (100% polyimide short fiber) used in Example 6 was used.
A sliver S1 was prepared as a core sliver, and a sliver S2 was prepared as a sheath sliver. Spinning was carried out in the same manner as in Example 6, except that the mass ratio of each sliver after drawing was set to S1:S2=20:80, and a two-layer structure spun yarn (spun yarn A ).
Two of these yarns were combined and twisted 16 times/2.54 cm in the S direction to obtain a two-ply yarn of a two-layer structure spun yarn (30/2 count). A woven fabric was obtained in the same manner as in Example 1, except that the obtained two-ply yarn was used.

Example 8
A sheet-like wrap was obtained by using 100% by mass of polyimide fiber and putting it into a cotton blending machine. At this time, the short polyimide fibers to be fed into the cotton blending machine were pre-applied with the same oil solution as in Example 1 at a rate of 0.1% by mass with respect to the total amount of the fibers.
Then, the carding process, the combing process, and the drawing process were performed under the same conditions as in Example 1 to obtain a curd sliver. At this time, the amount of static electricity generated in the web spun from the carding machine was -0.10 to -0.05 kv.
Eight of these card sliver were aligned in the drawing process, stretched 7.5 times to obtain sliver S, and then under the conditions of a sliver mass of 340 gr/6 yd (1 gr = 0.65 g, 1 yd = 0.9144 m). Fed to the roving machine. In the roving machine, the supplied sliver S is drawn (7.08 times), the twist number is 0.728 times / inch, and the roving weight is 240 gr / 30 yd (1 gr = 0.65 g, 1 yd = 0.9144 m). A rough yarn was obtained. This roving yarn was subjected to a spinning machine in the same manner as in Example 1 to obtain spun yarn of 30 count (British cotton count). Two of these yarns were combined and twisted 16 times/2.54 cm in the S direction to obtain a spun yarn (30/2 count). A woven fabric was obtained in the same manner as in Example 1, except that the obtained two-ply yarn was used.

Example 9
(sliver S1)
In the production of sliver S1 of Example 1, sliver S1 was obtained in the same manner as in Example 1, except that after obtaining the card sliver, it was subjected to the drawing step without undergoing the combing step.
(sliver S2)
The same sliver S2 of Example 1 was used.
A sliver S1 was prepared as a core sliver and a sliver S2 was prepared as a sheath sliver. .
Two of these yarns were combined and twisted 16 times/2.54 cm in the S direction to obtain a two-ply yarn of a two-layer structure spun yarn (30/2 count). A woven fabric was obtained in the same manner as in Example 1, except that the obtained two-ply yarn was used.

Example 10
(sliver S1)
The sliver S2 (flame-retardant rayon fiber 100%) of Example 1 was used.
(sliver S2)
In the production of sliver S1 of Example 6, sliver S2 (polyimide short fibers 100%) was obtained in the same manner as in Example 6, except that after obtaining the card sliver, it was subjected to the drawing step without the combing step. rice field.
A sliver S1 was prepared as a core sliver and a sliver S2 was prepared as a sheath sliver. to obtain a two-layer structure spun yarn (spun yarn A) of 30 count (British cotton count).
Two of these yarns were combined and twisted 16 times/2.54 cm in the S direction to obtain a two-ply yarn of a two-layer structure spun yarn (30/2 count). A woven fabric was obtained in the same manner as in Example 1, except that the obtained two-ply yarn was used.

Comparative example 1
(sliver S1)
62.5% by mass of polyimide fiber and 37.5% by mass of flame-retardant rayon fiber were mixed and put into a cotton blending machine to obtain a sheet-like wrap. No oil was previously applied to the fibers.
Then, the ambient temperature and humidity in the vicinity of the carding process were set to the same conditions as in Example 1, and the wrap obtained in the mixed cotton process was put into the carding machine.
For this reason, when the fibers combed from the doffer portion of the carding machine become a sheet (web), the ends of the web are curled up by static electricity, causing poor convergence (spots due to cutting and folding), and the card sliver. couldn't get. As a countermeasure, the same phenomenon occurred even when the humidity was set to about 70 to 90% (using a sprayer), and the problem could not be improved.
At this time, the amount of static electricity generated in the web spun from the carding machine was -2.0 to -1.5 kV.

Comparative example 2
(sliver S1)
80% by mass of polyimide fiber and 20% by mass of flame-retardant rayon fiber were mixed and put into a cotton blending machine to obtain a sheet-like wrap. At this time, the polyimide short fibers to be fed into the cotton blending machine were preliminarily applied with the same oil solution as in Example 1 at a rate of 0.02% by mass with respect to the total amount of the fibers. Then, the ambient temperature and humidity in the vicinity of the carding process were set to the same conditions as in Example 1, and the wrap obtained in the mixed cotton process was put into the carding machine. At this time, the amount of static electricity generated in the web spun from the carding machine was -0.50 to -0.30 kV.
As a result, as in Comparative Example 1, the web was not properly converged in the carding machine, and a card sliver could not be obtained.

Comparative example 3
(sliver S1)
62.5% by mass of polyimide fiber and 37.5% by mass of flame-retardant rayon fiber were mixed, and put into a cotton blending machine to obtain a sheet-like wrap. At this time, the polyimide short fibers to be introduced into the cotton blending machine were preliminarily applied with the same oil solution as in Example 1 at a rate of 0.4% by mass with respect to the total amount of the fibers.
Then, the ambient temperature and humidity in the vicinity of the carding process were set to the same conditions as in Example 1, and the wrap obtained in the mixed cotton process was put into a carding machine to obtain a card sliver. At this time, the amount of static electricity generated in the web spun from the carding machine was 0.00 kV, and a card sliver was obtained.
When the obtained card sliver was subjected to the drawing process, the fibers were frequently rolled up to the top roller (made of rubber) from about 20 kg of passing cotton, and the operation failure occurred frequently. When observing the surface of the top roller, it was found to be discolored and sticky due to the influence of the oil, which affected the passing fibers. For this reason, it was not possible to obtain a drawn sliver.

Comparative example 4
(sliver S1)
The sliver S2 (100% flame-retardant rayon fiber) used in Example 1 was used.
(sliver S2)
40.0% by mass of polyimide fiber and 60.0% by mass of flame-retardant rayon fiber were mixed and put into a cotton blending machine to obtain a sheet-like wrap. At this time, the short polyimide fibers to be fed into the cotton blending machine were pre-applied with the same oil solution as in Example 1 at a rate of 0.1% by mass with respect to the total amount of the fibers.
Then, the carding process, the combing process, and the drawing process were performed under the same conditions as in Example 1 to obtain a sliver S2. At this time, the amount of static electricity generated in the web spun from the carding machine was -0.03 to 0.00 kv.
A sliver S1 was prepared as a core sliver, and a sliver S2 was prepared as a sheath sliver.
1 (schematic cross-sectional view) and FIG. 2 (schematic cross-sectional view) are used to supply a sliver S1 for the core portion and a sliver S2 for the sheath portion, and the mass ratio of each sliver after stretching. are set to S1:S2=60:40, and the advancing angle θ of the core sliver S1 to the flyer head with respect to the draft direction in FIG. 0.9144 m) and a twist number of 0.984 turns/2.54 cm.
Spinning was carried out under the same conditions as in Example 1, except that this roving was used, to obtain a 30-count (British cotton count) two-layer structure spun yarn (spun yarn A).
Two of these yarns were combined and twisted 16 times/2.54 cm in the S direction to obtain a two-ply yarn of a two-layer structure spun yarn (30/2 count). A woven fabric was obtained in the same manner as in Example 1, except that the obtained two-ply yarn was used.

Comparative example 5
(sliver S1)
A sheet-like wrap was obtained by mixing 62.5% by mass of aramid fiber and 37.5% by mass of flame-retardant rayon fiber and putting the mixture into a cotton blending machine without applying oil. Otherwise, under the same conditions as in Example 1, the lap obtained in the mixed cotton step was put into a carding machine to obtain a card sliver.
(sliver S2)
The sliver S2 used in Example 1 was used.
A sliver S1 was prepared as a core sliver and a sliver S2 was prepared as a sheath sliver, and spun in the same manner as in Example 1 to obtain a two-layer structure spun yarn of 30 count (British cotton count). .
Two of these yarns were combined and twisted 16 times/2.54 cm in the S direction to obtain a two-ply yarn of a two-layer structure spun yarn (30/2 count). A woven fabric was obtained in the same manner as in Example 1, except that the obtained two-ply yarn was used.

Comparative example 6
A card sliver was obtained by using 100% by mass of aramid fiber and putting it into a cotton blending machine and a carding machine. Otherwise, under the same conditions as in Example 1, the lap obtained in the mixed cotton step was put into a carding machine to obtain a card sliver.
In the drawing process, this card sliver was drawn into 8 strands and stretched 7.5 times to obtain a sliver S. Then, the sliver mass was 340 gr/6 yd (1 gr = 0.65 g, 1 yd = 0.9144 m). Fed to the roving machine. In the roving machine, the supplied sliver S is drawn (7.08 times), the twist number is 0.728 times / inch, and the roving weight is 240 gr / 30 yd (1 gr = 0.65 g, 1 yd = 0.9144 m). A rough yarn was obtained.
This roving yarn was subjected to a spinning machine in the same manner as in Example 1 to obtain spun yarn of 30 count (British cotton count). Two of these yarns were combined and twisted 16 times/2.54 cm in the S direction to obtain a spun yarn (30/2 count). A woven fabric was obtained in the same manner as in Example 1, except that the obtained two-ply yarn was used.

Comparative example 7
A mixture of 25% by mass of polyimide fiber and 75% by mass of flame-retardant rayon fiber was put into a cotton blending machine to obtain a sheet-like wrap. At this time, the polyimide short fibers to be fed into the cotton blending machine were pre-applied with the same oil solution as in Example 1 at a rate of 0.05% by mass with respect to the total amount of the fibers.
Then, a card sliver was obtained through a carding process in the same manner as in Example 1. At this time, the amount of static electricity generated in the web spun from the carding machine was -0.05 to -0.01 kv.
Eight of this card sliver were aligned in the drawing process and stretched 7.5 times to obtain sliver S. Then, the sliver mass was 340 gr / 6 yd (1 gr = 0.65 g, 1 yd = 0.9144 m). supplied to the roving loom. In the roving machine, the supplied sliver S is drawn (7.08 times), the number of twists is 0.977 times / 2.54 cm, and the roving mass is 240 gr / 30 yd (1 gr = 0.65 g, 1 yd = 0.9144 m ) was obtained. This roving yarn was subjected to a spinning machine in the same manner as in Example 1 to obtain spun yarn of 30 count (British cotton count). Two of these yarns were combined and twisted 16 times/2.54 cm in the S direction to obtain a spun yarn (30/2 count). A woven fabric was obtained in the same manner as in Example 1, except that the obtained two-ply yarn was used.

Test example 1
The spun yarns and woven fabrics obtained in Examples and Comparative Examples were measured or evaluated according to the above measuring method and evaluation method. The results are shown in Tables 2 and 3. Table 1 also shows the manufacturing conditions and composition of each spun yarn and fabric.

As is clear from these results, the spun yarns obtained in Examples 1 to 8 have excellent heat resistance, chemical resistance, and abrasion resistance, which are excellent characteristics of polyimide fibers. It was possible to impart a soft texture to the resulting woven or knitted fabric.
Among them, the fabrics obtained from the spun yarns obtained in Examples 1 to 5 were excellent in dyeability in addition to soft touch. Moreover, since the spun yarns obtained in Examples 6 to 8 were particularly excellent in heat resistance and abrasion strength, the obtained fabrics were sufficiently endowed with these properties.

Claims (10)

A spun yarn containing polyimide short fibers,
(1) The content of polyimide short fibers having a fiber length of 20 to 80 mm is 50% by mass or more, and at least one of polyamide fibers, polyester fibers, acrylic fibers, cellulose fibers and polyvinyl alcohol fibers. Containing a polyimide short fiber bundle with a content of 0 to 50% by mass ,
(2) The content of polyimide short fibers in the spun yarn is 20% by mass or more,
(3) the spun yarn is a twisted yarn,
A spun yarn characterized by: 2. The spun yarn containing polyimide short fibers, having a core portion and a sheath portion in a cross section perpendicular to the longitudinal direction of the yarn, wherein the sheath portion is the polyimide short fiber bundle. spun yarn. 2. The spun yarn containing polyimide short fibers, having a core portion and a sheath portion in a cross section perpendicular to the longitudinal direction of the yarn, wherein the core portion is the polyimide short fiber bundle. spun yarn. 4. The spun yarn according to claim 3, wherein the sheath contains 50% by mass or more of cellulosic fibers. 5. The area ratio of the core portion and the sheath portion in a cross section perpendicular to the longitudinal direction of the yarn is 80:20 to 20:80. spun yarn. The spun yarn according to any one of claims 1 to 5, which has a Worcester spot (U%) of 13% or less. The spun yarn according to any one of claims 1 to 6, having a twist coefficient K of 3.0 to 6.0. A woven or knitted fabric comprising the spun yarn according to any one of claims 1 to 7. A method for producing a spun yarn, comprising the following steps (1) and (2):
(1) Using a short fiber raw material containing 100 parts by mass of polyimide short fibers having a fiber length of 20 to 80 mm and 0.05 to 0.3 parts by mass of a surfactant as an oil agent , the polyimide short fibers are processed by a mixed cotton treatment. obtaining a sheet-like wrap containing 50% by mass or more and 0 to 50% by mass of at least one of polyamide fibers, polyester fibers, acrylic fibers, cellulose fibers and polyvinyl alcohol fibers; and (2) the above. The method is characterized by including a step of obtaining a card sliver while adjusting the amount of static electricity generated in the web obtained after the carding treatment within the range of -0.2 to +0.2 kv when carding the sheet-like wrap. A method for producing a spun yarn. Further, in the roving step (3), a plurality of drawing sliver obtained from the card sliver is used, at least one drawing sliver is used as a core sliver, and other drawing sliver is wound around the core sliver. 10. The manufacturing method according to claim 9, comprising the step of obtaining a roving having a two-layer structure by spinning together.

Images