JP6744063B2 - Spun yarn and woven and knitted fabrics - Google Patents

Description

TECHNICAL FIELD The present invention relates to a spun yarn containing crimped high-strength aramid short fibers, and a woven or knitted fabric using the spun yarn.

Para-aramid fiber spun yarns are known as spun yarns having higher strength than spun yarns obtained by spinning natural fibers such as cotton and hemp. For example, the nominal tensile strength of Kevlar (registered trademark) soft spun yarn (yarn spun from short cut soft cotton) is 7.6 cN/dtex (see Patent Document 1). The para-aramid spun yarn can be produced in the same manner as the natural fiber, using short fibers (staples) obtained by cutting the para-aramid long fibers into a length suitable for the spinning process. Since the tensile strength of standard Kevlar (registered trademark) 29 type long fibers is 20.3 cN/dtex, the excellent characteristics of para-aramid fibers are not fully utilized when processed into spun yarn. There is a situation.

However, since para-aramid fiber has high strength and high rigidity, it is possible to make use of spun yarn by taking advantage of functionality such as texture, flexibility, feel, hygroscopicity, and blendability that cannot be obtained with long fibers. It has been used in various fields and expanded its applications. For example, protective materials such as gloves, arm covers, and aprons that use woven and knitted para-aramid fibers have better cut resistance than conventional gloves, arm covers, and apros that use cotton. Periodly high. Therefore, for example, in the automobile industry, in the home electric appliances industry such as washing machines and refrigerators, work that deals with sheet metal products with burrs, glass industry that handles fragile glass products, or metal pieces or glass pieces may be mixed. It has been widely used to protect a worker's hands and body in a work that is prone to a cut accident, such as a garbage collection work that handles general dust.

However, from the viewpoint of strength, spun yarn is generally composed of an aggregate of short fibers, the short fibers have crimps, the arrangement of the yarns is low, and the yarn has a twisted form. As described above, the strength of the yarn is apt to decrease as compared with the strength of the long fibers constituting the yarn, and it has been difficult to develop into a field requiring the strength.

As a method for obtaining a high-strength spun yarn, a draw-cut spun yarn (for example, Patent Document 2) in which short fiber yarns are aligned and then entangled with a fluid nozzle to be taken, and actions such as friction, bending, and elongation are performed. There is a core-sheath two-layer structure spun yarn (for example, Patent Document 3) in which the core part and the sheath part do not slip and the fibers of the sheath part are peeled off even when receiving the yarn. However, the stretch-spread spun yarn and the spun yarn having a two-layer core-sheath structure have a drawback that the manufacturing process is complicated and the economical efficiency is poor.

On the other hand, spinning methods other than the tow type (for example, cotton spinning type, worsted type, etc.) are characterized by the good texture of the fiber structure, so it is highly expected that they are high-strength spun yarns. It has not been. In addition, short fibers such as nylon and polyester have been studied for mixing aramid short fibers obtained by cutting aramid filaments (for example, Patent Document 4), but when improving cut resistance, abrasion resistance, etc. It is necessary to set the mixing ratio of aramid short fibers to 20% by weight or more, and the desired effect is not obtained at a low mixing ratio.

Special table 2005-537398 gazette JP, 2005-171453, A JP, 2006-161179, A JP-A-8-109530

In view of such background of the prior art, the present invention can be produced by a spinning equipment that performs a spinning method that is not a tow type (for example, a cotton spinning type, a worsted type, etc.), and aramid even if the mixing ratio in the spun yarn is low. An object of the present invention is to provide a spun yarn in which the effect possessed by fibers is exhibited, and a woven or knitted product using the spun yarn.

The present inventors have conducted extensive studies to solve such problems, and as a result, by mixing high-strength aramid short fibers having crimps, the strength of spun yarn is dramatically improved even at a low mixing ratio, The present inventors have found that a spun yarn exhibiting a behavior completely different from that of the spun yarn obtained by blending the aramid short fibers of (1) is obtained, and arrived at the present invention.

That is, the present invention is as follows.

(1) High-strength polyparaphenylene terephthalamide short fibers having a crimped short fiber having a tensile strength of 21 to 25 cN/dtex measured according to JIS L 1015, and other short fibers Which is a mixed yarn of
The high-strength polyparaphenylene terephthalamide short fibers have a strength retention of 90% or more with respect to the tensile strength of the polyparaphenylene terephthalamide long filament single yarn, and a mixing ratio of 5 to 95% by weight based on the total weight of the mixed spun yarn. A mixed spun yarn characterized by being contained in.
(2) In (1) above, the fineness of the high-strength polyparaphenylene terephthalamide short fibers is 1.0 to 5.0 dtex, the average fiber length is 25 to 200 mm, and the number of crimps is 3 to 12 peaks/25.4 mm. Blended spun yarn as described.
(3) The mixed spun yarn according to (1) or (2), wherein the high-strength polyparaphenylene terephthalamide short fibers are obtained by cutting the crimped yarn of the polyparaphenylene terephthalamide long fibers.
(4) The mixed spun yarn according to any one of (1) to (3), wherein the twist coefficient is 2.5 to 6.0 and the cotton count is 5 to 40 count.
(5) A woven or knitted fabric containing the mixed spun yarn according to any one of (1) to (4).

According to the present invention, by using high-strength aramid short fibers in a predetermined mixing ratio, high-strength, high-strength mixed spinning that cannot be obtained with conventional spun yarns such as nylon-based, polyester-based, acrylic-based or rayon-based fibers. It becomes possible to provide the yarn. Further, since the manufacturing process is simple, there is an advantage that the manufacturing can be performed at low cost. Further, by constructing a woven or knitted product using the spun yarn of the present invention, it becomes possible to develop the spun yarn for new applications.

The crimped high-strength aramid short fibers constituting the spun yarn of the present invention have a tensile strength of 21 to 25 cN/dtex.
Preferably, it is obtained by cutting a crimped yarn of polyparaphenylene terephthalamide (hereinafter sometimes abbreviated as PPTA) long fibers by a known method.
Here, in the present invention, the “tensile strength of a PPTA continuous fiber single yarn” (hereinafter sometimes referred to as “single yarn tensile strength”) means that one single yarn is taken out from a continuous fiber (multifilament). , "Tensile strength of high-strength aramid short fibers" means that one short fiber is taken out from an aggregate of short fibers and is specified in Annex C of JIS L 1015. It is the tensile strength measured based on the above.

In the above high-strength aramid short fiber, the fineness is preferably in the range of 1.0 to 5.0 dtex, more preferably 1.0 to 3.8 dtex, and particularly preferably 1.5 to 3.6 dtex. When the fineness is less than 1.0 dtex, it becomes difficult to achieve the tensile strength of the high-strength aramid short fiber of 21 cN/dtex or more, and it becomes difficult to obtain a spun yarn with high strength and high strength. On the other hand, when the fineness exceeds 5.0 dtex, when the thickness of the spun yarn is adjusted to the same count, the entanglement of the yarn is reduced due to the reduction of the short fibers constituting the spun yarn, and a high-strength spun yarn is obtained. It's hard to be beaten. In addition to the poor processability, texture, flexibility, and feel of the spun yarn using the spun yarn, the woven or knitted fabric made of the spun yarn is also hard and difficult to handle.

In order to obtain good spinnability, the fiber length of the high-strength aramid short fibers is preferably in the range of 25 to 200 mm, more preferably 30 to 110 mm as the average fiber length. Within this range, spun yarn can be easily manufactured by a spinning method other than the conventional tow type (for example, cotton spinning type, worsted type, etc.).

The number of crimps of the high-strength aramid short fibers is preferably 3 to 12 peaks/25.4 mm, more preferably 5 to 10 peaks/25.4 mm. When the number of crimps is less than 3 peaks/25.4 mm, it becomes difficult to obtain a spun yarn having texture and flexibility. On the other hand, when the number of crimps exceeds 12 peaks/25.4 mm, there is a concern that the strength may decrease due to buckling, rubbing, etc. of the PPTA long fibers.

The high-strength aramid short fibers preferably have 0.01 to 1.5% by weight of an oil agent attached to the fiber surface. It is more preferably 0.1 to 0.5% by weight. In particular, when producing spun yarn, it is necessary to cut a crimped continuous long fiber bundle (tow) to a predetermined length, perform a knitting cotton and a card process, and then carry out roving and spinning. When the aramid fiber is rubbed against a roller (particularly a spinning machine roller), it has a fiber structure which is originally prone to fibrillation, and thus a large number of fibrils are formed, and the fibers fall off in various steps. Since the oil agent is attached, the fibers are prevented from falling off during the spinning process, and high quality spun yarn is provided. A known compound can be used as the oil agent, and only the oil agent may be used, or an oil agent composition in which an antistatic agent and an antifoaming agent are further used in combination may be used.

The high-strength aramid short fibers having the above physical properties are obtained by collecting a plurality of PPTA long fibers that have no history of being dried to a moisture content of less than 15% by weight after spinning into a continuous long fiber bundle (tow). Are washed through the bath to wash out the raw thread oil agent to 0.5% by weight or less, and then passed through a steam bath at about 80°C. These tows are pressed in and crimped by a crimper to apply a spinning oil. Then, it can be suitably obtained by drying to a moisture content of 6% by weight or less and cutting it into a predetermined length.

Here, the PPTA continuous fiber having no history of being dried to have a water content of less than 15% by weight after spinning means that the water content of the fiber is less than 15% by weight after spinning the fiber and immediately before crimping. It means that there is no history of becoming. Further, the water content (R) in the PPTA long fiber is a value obtained by the following formula. The absolute dry weight means a weight measured after taking about 3 g of a sample and drying it in an oven at 105° C. for 4 hours.
R={(m ₁ −m ₂ )/m ₂ }×100
R: Moisture content [%]
m ₁ : Weight [g] when the sample was collected
m ₂ : absolute dry weight of sample [g]

Polyparaphenylene terephthalamide (PPTA) is a polymer obtained by polycondensing terephthalic acid and paraphenylenediamine, but a polymer obtained by copolymerizing a small amount of dicarboxylic acid and diamine can also be used. The molecular weight of is usually preferably 20,000 to 25,000.

The best mode for obtaining PPTA filaments having a moisture content after spinning of less than 15% by weight and having no history of drying is to dissolve polyparaphenylene terephthalamide (PPTA) in concentrated sulfuric acid to give 18 to 20 A viscous solution of wt% was discharged from the spinneret, spun into air for a short time, and then spun into water (at this time, the shear rate at the time of discharging the spinneret was 25,000 to 50,000 sec. ^-1 ), and then the fiber coagulated in the spinning bath is neutralized with an aqueous sodium hydroxide solution, and then dried at 100 to 160° C., preferably for 5 to 20 seconds to obtain a water content. A method of preparing the PPTA continuous fiber in a state of 15 to 100% by weight can be mentioned.

After that, the PPTA long fibers are stored in an atmosphere at room temperature until a plurality of PPTA long fibers are collected into a tow. At this time, the water content on the surface of the PPTA fibers evaporates and the water content becomes less than 15% by weight. Take measures to prevent this. More preferred is a PPTA long fiber prepared by preparing a PPTA long fiber having a water content of 15 to 100% by weight and storing it so as to keep the water content. When the moisture content when crimping by the indentation crimper by the indentation method is less than 15% by weight, the structure containing voids in the fiber is apt to be physically damaged by the crimper, while when it exceeds 100% by weight, the crimper However, it is difficult to handle in the process of winding the fiber, and the drying efficiency after crimping is also reduced. A more preferable water content is 15 to 50% by weight, and a particularly preferable water content is 20 to 45% by weight.

Further, the high-strength aramid short fibers used in the spun yarn of the present invention can be obtained by cutting the crimped yarn of the PPTA long fiber obtained by the above method by a conventional method. The fact that the strength of the high-strength aramid short fibers does not decrease is indicated by the strength retention rate calculated by the following formula. That is, the higher the value of the strength retention rate is, the less the strength is reduced. The high-strength aramid short fiber and the PPTA long fiber single yarn at the time of strength measurement have a water content of 6% or less.
Strength retention (%)=[tensile strength of high-strength aramid short fibers (cN/dtex)/tensile strength of PPTA long fiber single yarn (cN/dtex)]×100

The high-strength aramid short fibers used in the spun yarn of the present invention have a tensile strength retention rate of the short fibers of 90% or more with respect to the tensile strength of the long fiber single yarn having no crimp. Considering that the strength retention rate is 75%, it shows an epoch-making high value. Further, by appropriately selecting the fineness, the number of crimps, and the crimping processing conditions, it is possible to achieve 92% or more, further 95% or more. The high-strength aramid short fibers thus obtained have a tensile strength in the range of 21 to 25 cN/dtex, and show an epoch-making higher value than the conventional crimped aramid short fibers.

In the spun yarn of the present invention, the short fibers (blended cotton short fibers) used together with the high-strength aramid short fibers are not particularly limited, and examples thereof include polyester (polyethylene terephthalate, polyethylene naphthalate, wholly aromatic polyester, etc.) fibers, nylon ( Nylon 6, nylon 66 etc.) fiber, rayon fiber, acrylic fiber, polyethylene (high strength polyethylene etc.) fiber, aramid (meta aramid, para aramid) fiber, polyether sulfide (PPS) fiber, polyimide (PI) fiber, Short fibers of synthetic fibers such as polybenzimidazole (PBI) fibers, polybenzoxazole (PBO) fibers, polyamideimide (PAI) fibers and polyetherimide (PEI) fibers; natural fibers such as cotton, hemp and wool; flame retardant Short fibers of flame-retardant fibers such as acrylic (modacrylic) fibers, polyclar fibers, flame-retardant polyester fibers, flame-retardant rayon fibers, flame-retardant vinylon fibers, flame-retardant wool fibers, flame-retardant cotton fibers, flame-retardant fibers; metal fibers, carbon fibers , Short fibers of inorganic fibers and the like. These short fibers can be produced by a known method.
Among the above short fibers, synthetic fibers such as acrylic fibers, nylon fibers, polyester fibers and rayon fibers are required from the viewpoint of improvement in tensile strength, cut resistance, heat resistance or abrasion resistance of spun yarn. Of the above-mentioned short fibers and the short fibers of the flame-retardant fibers obtained by subjecting these synthetic fibers to the flame-retardant treatment are preferable.

The mixed cotton short fibers are not limited as long as they pass through the spinning process, such as fineness, fiber length, and the number of crimps when crimped. For example, the single fiber fineness is 0.6 to 6 Preferably, the fiber length is 0.0 dtex and the fiber length is 20 to 100 mm. The mixed cotton short fibers and the high-strength aramid short fibers may have the same single fiber fineness or fiber length, or may have different fiber lengths. In order to obtain a spun yarn having high tensile strength, it is preferable that the fiber length be long, but from the viewpoint of processability in the spinning process, 100 mm or less is desirable. From the viewpoint of processability in the spinning process, it is preferable that the mixed cotton short fibers and the high-strength aramid short fibers have the same fiber length.

In the spun yarn of the present invention, the mixing ratio of the high-strength aramid short fibers is 5 to 95% by weight based on the total weight of the spun yarn. It is more preferably 10 to 90% by weight, and particularly preferably 15 to 85% by weight. When the mixing ratio of the high-strength aramid short fibers is less than 5% by weight, it becomes difficult to obtain a high-strength and high-strength spun yarn, while when it exceeds 95% by weight, the characteristics of the mixed cotton short fibers are difficult to obtain. Become.

The spun yarn of the present invention can be produced by using the above-mentioned both short fibers in the existing cotton spinning, soft spinning or worsted spinning equipment. For example, it can be produced through each spinning process of carding, drawing, roving, and spinning, and the high-strength aramid short fibers and the mixed short cotton fibers are mixed with each other at a predetermined mixing ratio in, for example, a mixed-plied cotton process or a kneading process. Can be mixed with.

Although the thickness of the spun yarn depends on the application, it is usually preferably used in the range of 40s to 5s. The form of spun yarn used for knitting woven or knitted fabrics or gloves is a mixed spun yarn or a spun yarn twin yarn in which two spun yarn single yarns are aligned and twisted in the opposite direction to the spun yarn single yarn. The yarn count of the spun yarn twin yarn is preferably 40/2s to 5/2s, and within the above range, the workability is not significantly impaired.
It should be noted that the English cotton count has a yarn length of 768.10 m (840 yards) per 453.6 g (1 lb) is called 1st count, and the thinner the yarn, the larger the count.

As for the twist of the spun yarn, it is preferable that the twist coefficient (K ₂ ) obtained by the following equation is twisted in the range of 2.5 to 6.0. When the twisting coefficient (K ₂ ) is less than 2.5, the entanglement between the high-strength aramid short fibers becomes too weak, and the ends of the short fibers protrude from the spun yarn, and the woven or knitted fabric tends to have a stinging feeling. On the other hand, when the twist coefficient (K ₂ ) is more than 6.0, the strength becomes excessively strong and the double twist is strongly generated to deteriorate the workability, the tensile strength of the spun yarn is lowered, and the texture is deteriorated. Tend to do. A more preferable twist coefficient (K ₂ ) is in the range of 2.5 to 3.5. The twist direction of the spun yarn single yarn may be either S or Z.

Twisting coefficient K ₂ =T ₁ /s ^1/2
T ₁ : Number of twists (times/25.4 mm)
s: Cotton count

When weaving the spun yarn of the present invention into a woven fabric, the weave structure is plain weave, twill weave, satin weave, or when knitting into a knitted fabric, warp knitting, weft knitting, etc. according to the desired texture and design. Can be selected.

Further, the woven or knitted fabric of the present invention may be wholly composed of the spun yarn of the present invention, or may be partially used. For example, in a work glove, the woven or knitted fabric of the present invention can be used for a specific part such as only a fingertip part or a palm part depending on the work content. Moreover, the woven or knitted fabric may be coated with a resin, if necessary.

The spun yarn of the present invention and the woven or knitted fabric containing the spun yarn are particularly suitable for applications in which severe environmental conditions for use are required. This includes not only those used directly for protective purposes, but also those that result in a protective function, such as work or industrial work clothing, industrial gloves, arm covers, apron, In addition to ankle covers, work shoes, footwear, welding work clothing; sportswear such as sports outerwear, trousers, shoes, baseball and soccer socks, fencing uniforms; firefighting clothing, welding work curtains, firefighting Hoses, tire cords, upholstered fabrics, various reinforcing fabrics, and the like, but not limited to these.
Furthermore, the spun yarn of the present invention has a function of imparting the tensile strength, high elastic modulus, abrasion resistance, cut resistance, and heat resistance of the aramid fiber to the characteristics of the mixed cotton fiber (for example, flame retardancy). Therefore, there are great expectations for new industrial materials for which spun yarn has not been used until now.

Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples. In addition, the measuring method of each physical property value in the following Examples and Comparative Examples is as follows. In addition, "%" represents weight%.

[Tensile strength and elongation of PPTA long fiber single yarn and high strength aramid short fiber]
Conforms to JIS L 1015 "Chemical fiber staple test method" 8.7.1 Standard time test.

[Test method for spun yarn]
JIS L 1095:2010 "General spun yarn test method" 9.5 (tensile strength and elongation rate of single yarn) JIS method a) Evaluate the characteristics of spun yarns in accordance with 9.8 (hooking strength) at standard time. .. A tensile tester was used to measure the load (N) and elongation (cm) when the sample was cut at a grip interval of 200 mm and a pulling speed of 200 mm/min. Under the same conditions, the load (N) and the elongation (cm) when the hooking part was cut were measured.

(Examples 1 and 2)
Polyparaphenylene terephthalamide (PPTA) (intrinsic viscosity=6.5) was dissolved in 99.9% concentrated sulfuric acid to prepare a spinning dope with a polymer concentration of 19.5% and a temperature of 80° C. After spinning, it is introduced into water at 4°C for coagulation, guided to a Nelson roller, neutralized with an 8% aqueous sodium hydroxide solution, washed with water and dried while maintaining the temperature of the fiber at 90°C or less It was wound into a tube to obtain PPTA long fibers having a total fineness of 1,594 dtex (converted to dryness). The moisture content of this fiber was 35%.
A plurality of the obtained PPTA long fibers (single yarn fineness 1.67 dtex (absolute dry basis), moisture content 35%, single yarn tensile strength 23.7 cN/dtex) were collected to form a continuous long fiber bundle (tow). Was passed through the bath to wash off the raw thread oil, and subsequently passed through a steam bath at about 80°C. These tows were pushed in and crimped with a crimper to apply a spinning oil. Then, it was dried to a water content of 6% or less to obtain a crimped yarn of PPTA long fiber. The resulting crimped yarn was cut with a cutter to obtain a high-strength aramid short fiber (water content 5%) having a fiber length of 51 mm and a crimp number of 8 peaks/25.4 mm.

The obtained high-strength aramid short fibers (single-fiber fineness 1.67 dtex (absolute dry basis), fiber length 51 mm) and acrylic short-fiber (Toray Industries, Inc. "Trellon", single-fiber fineness 2.2 dtex, fiber length 51 mm 10% and 15% of high-strength aramid short fibers were mixed with the acrylic short fibers, and a sliver was made by passing through the card and the kneading order in this order.
Next, this was set in a ring spinning machine, and twists of 14 twists/25.4 mm and a twist of Z twist in the twisting direction were added to obtain a spun yarn single yarn of cotton count 16s.

(Comparative Examples 1-2)
Continuous long fibers by collecting multiple PPTA long fibers (single yarn fineness 1.67 dtex "Kevlar (R) 29" manufactured by Toray DuPont Co., Ltd., official moisture content of 7%, single yarn tensile strength 23.0 cN/dtex). A bundle (tow) was made, and this tow was passed through a bath to wash away the raw yarn oil agent, and subsequently passed through a steam tank at about 80°C. These tows were pushed in and crimped with a crimper to give a spinning oil, and then dried to a water content of 6% or less to obtain crimped PPTA filaments.
The obtained crimped yarn was cut to obtain crimped aramid short fibers (water content 6%) having a fiber length of 51 mm and a crimp number of 8 peaks/25.4 mm.
Using the obtained crimped aramid short fibers (single yarn fineness 1.67 dtex (absolute dry basis), fiber length 51 mm) and acrylic short fibers (single yarn fineness 2.2 dtex, fiber length 51 mm), the acrylic short fibers were obtained. 10% and 15% of crimped aramid short fibers were mixed, and a spun yarn single yarn of cotton count 16s was obtained in the same manner as in Example 1.

The properties of these spun yarns are shown in Table 1.

As shown in Table 1, the spun yarn of the present invention containing 10% (Example 1) and 15% (Example 2) of high-strength aramid short fibers has strength and tenacity of 10 to 13 as compared with 100% acrylic spun yarn. %, the spun yarn containing 15% of the comparative product (Comparative Example 2) has an increase rate of strength or tenacity of 5% or less, and the spun yarn containing 10% of cotton (Comparative Example 1) is 100% acrylic. % The strength and tenacity tended to be lower than those of the spun yarn.

(Examples 3 to 4)
The high-strength aramid short fibers (single yarn fineness 1.67 dtex, fiber length 51 mm) obtained in Example 1 and modacrylic short fibers (Kaneka's "Protex", single yarn fineness 2.2 dtex, fiber length 51 mm) are used. Other than that, in the same manner as in Example 1, a spun yarn single yarn with 14 twists/25.4 mm and a cotton count of 16 s was obtained.

(Comparative Examples 3 to 4)
The same method as in Example 3 except that the same crimped aramid short fibers as in Comparative Example 1 were used in place of the high-strength aramid short fibers, and the number of twists was 14 times/25.4 mm and the cotton yarn was 16s. I got a single yarn.

At the same time, spun yarn of 100% high-strength aramid short fibers obtained in Example 1 (Reference Example 2), spun yarn of 100% crimped aramid short fibers obtained in Comparative Example 1 (Reference Example 3), and modacrylic A spun yarn of 100% short fibers (Reference Example 4) was obtained.

The properties of these spun yarns are shown in Table 1.

From Table 2, the spun yarn of the present invention (Example 3) in which 10% of high-strength aramid short fiber is mixed is improved in strength and tenacity by 1 to 4% as compared with the modacrylic 100% spun yarn. On the contrary, in the spun yarn in which 10% of the cotton was mixed (Comparative Example 3), strength reduction was observed. Further, the spun yarn of the present invention (Example 4) in which 15% of high-strength aramid short fiber was mixed was improved in strength and tenacity by 12 to 13% as compared with the modacrylic 100% spun yarn. % Of the spun yarn (Comparative Example 4) mixed with each other, the strength and tenacity improvement rate was 5% or less.

By mixing the high-strength aramid short fibers of the present invention with other short fibers, a mixed spun yarn having the characteristics of aramid fibers can be obtained even in a low mixing ratio region. Therefore, the mixed spun yarn should be processed into a woven or knitted fabric or the like. As a result, it becomes possible to develop applications that could not be used conventionally due to insufficient strength or the like.

Claims (5)

A mixed fiber of short fibers having crimps and having a high strength of polyparaphenylene terephthalamide short fibers having a tensile strength measured according to JIS L 1015 of 21 to 25 cN/dtex and other short fibers. A thread,
The high-strength polyparaphenylene terephthalamide short fibers have a strength retention of 90% or more with respect to the tensile strength of the polyparaphenylene terephthalamide long filament single yarn, and a mixing ratio of 5 to 95% by weight based on the total weight of the mixed spun yarn. A mixed spun yarn characterized by being contained in. The blended spun fabric according to claim 1, wherein the high-strength polyparaphenylene terephthalamide short fibers have a fineness of 1.0 to 5.0 dtex, an average fiber length of 25 to 200 mm, and a crimp number of 3 to 12 peaks/25.4 mm. yarn. The mixed spun yarn according to claim 1 or 2, wherein the high-strength polyparaphenylene terephthalamide short fiber is obtained by cutting a crimped yarn of polyparaphenylene terephthalamide long fiber. The spun yarn according to any one of claims 1 to 3, wherein the twist coefficient is 2.5 to 6.0 and the cotton count is 5 to 40 count. A woven or knitted fabric containing the mixed spun yarn according to any one of claims 1 to 4.