WO2024013790A1

WO2024013790A1 - Multilayer-structured spun yarn, method for producing same, heat-resistant cloth, and heat-resistant protective garment

Info

Publication number: WO2024013790A1
Application number: PCT/JP2022/027218
Authority: WO
Inventors: 岡部孝之; 高田卓也; 田先慶多; 安田智則
Original assignee: 日本毛織株式会社
Priority date: 2022-07-11
Filing date: 2022-07-11
Publication date: 2024-01-18
Also published as: CN117693616A

Abstract

Provided is a multilayer-structured spun yarn (20) in which each of core component fibers (21) comprises a p-aramid fiber draft-cut yarn and each of sheath component fibers (25) comprises a polybenzimidazol fiber and an aramid fiber, in which the aramid fiber in the sheath component fibers (25) comprises a p-aramid fiber and a m-aramid fiber, and, when the amount of the sheath component fibers (25) is defined as 100% by mass, the polybenzimidazol fiber, the p-aramid fiber and the m-aramid fiber are blended in amounts of 50 to 65% by mass, 18 to 35% by mass and 3 to 18% by mass, respectively. As one embodiment, the multilayer-structured spun yarn (20) has such a configuration that some of the sheath component fibers (25) are surface-layer-wound fibers (23) and the remaining fibers of the sheath component fibers (25) are arranged in the direction of the length of the multilayer-structured spun yarns (20), the surface-layer-wound fibers (23) are in such an actual twisted form that the fibers are twisted in one direction and bundle the fibers together. According to this configuration, a multilayer-structured spun yarn having improved frictional strength, burning/bursting strength and discoloration resistance to washing and friction, a method for producing the multilayer-structured spun yarn, a heat-resistant cloth, and a heat-resistant protective garment are provided.

Description

Multilayer spun yarn, its manufacturing method, heat-resistant fabric, and heat-resistant protective clothing

The present invention relates to a multilayer spun yarn in which the core component fiber is a tension-cut spun yarn of heat-resistant fibers and the sheath component fibers include heat-resistant short fibers, a method for producing the same, a heat-resistant fabric, and a heat-resistant protective clothing.

Protective clothing is used as work clothes by firefighters, emergency personnel, lifesaving personnel, maritime rescue workers, the military, oil-related facility workers, chemical factory workers, etc. In recent years, polybenzimidazole fibers with excellent heat resistance and flame retardancy have been used in firefighting suits in the United States, Canada, Australia, and some parts of Europe. Since this fiber has a weak strength of about 2.4 cN/decitex (hereinafter abbreviated as dtex), a woven fabric interwoven with p-aramid fiber is usually used. This woven fabric is composed of warps or wefts, one of which is a spun yarn made of polybenzimidazole fiber, and the other yarn is a filament yarn made of p-aramid fiber. As another fabric with excellent heat resistance and flame retardancy, the present inventors used a tension-cut spun yarn of p-aramid fiber for the core and m-aramid fiber, flame-retardant acrylic fiber, or polyetherimide fiber for the sheath. have proposed core-sheath spun yarns using such materials (Patent Documents 1 and 2). Furthermore, in Patent Document 3, the present inventors used a tension-cut spun yarn of p-aramid fiber for the core, and used a blended fiber of flame-retardant fiber other than p-aramid fiber and polybenzimidazole fiber for the sheath. Patent Document 4 proposes a multilayer spun yarn using a tension-cut spun yarn of p-aramid fiber for the core and a blended fiber of p-aramid fiber and polybenzimidazole fiber for the sheath. is proposed.

WO2009/014007 publication WO2012/137556 publication Patent No. 5972420 Patent No. 6599496

However, all of the above conventional techniques have problems with frictional strength, combustion bursting strength, and discoloration and fading due to washing.

In order to solve the above-mentioned conventional problems, the present invention provides a multilayer spun yarn with improved frictional strength, combustion bursting strength, and washing friction discoloration, a method for producing the same, a heat-resistant fabric, and a heat-resistant protective clothing.

The multilayered spun yarn of the present invention is a multilayered spun yarn in which the core component fiber is a p-aramid fiber tension-cut yarn, and the sheath component fiber includes polybenzimidazole fiber and aramid fiber, wherein the sheath component fiber is aramid fiber. The fibers include p-aramid fibers and m-aramid fibers, and when the sheath component fiber is 100% by mass, polybenzimidazole fibers are 50 to 65% by mass, p-aramid fibers are 18 to 35% by mass, m- The aramid fibers are characterized by being blended at a ratio of 3 to 18% by mass.

The method for producing a multilayered spun yarn of the present invention is the method for producing a multilayered spun yarn described above, in which a sliver of heat-resistant staple fibers to be a sheath component fiber is supplied to a draft zone and drafted. A tension-cut spun yarn of a heat-resistant fiber serving as a core component fiber is supplied to a front roller, and is combined with the drafted short fiber bundle, and the combined yarn is placed on a spindle located away from the discharge section of the front roller. It is characterized by supplying a tension-cut spun yarn and a drafted short fiber bundle, false twisting it using a swirling flow, and then winding it up.

The heat-resistant fabric of the present invention is characterized by using the multilayered spun yarn described above. Moreover, the heat-resistant protective clothing of the present invention is characterized by containing the above-mentioned heat-resistant fabric.

The multilayered spun yarn of the present invention has a multilayered spun yarn that has acceptable levels of frictional strength, combustion bursting strength, and washing friction discoloration by optimizing the composition of heat-resistant fibers, its manufacturing method, and heat resistance. We can provide fabrics and heat-resistant protective clothing. Since the method for producing the multilayer spun yarn of the present invention is a bundle spinning method, it can be spun at about 20 times faster than the ring spinning method, and can be produced efficiently, rationally, and at low cost.

FIG. 1 is a schematic perspective view showing the main parts of a binding spinning device for producing a core-sheath structured spun yarn in an embodiment of the present invention. FIG. 2 is a schematic perspective view of a core-sheath structured spun yarn in one embodiment of the present invention. FIG. 3 is a side view photograph (magnification: 200 times) of a spun yarn with a core-sheath structure in one embodiment of the present invention. FIG. 4 is a side photograph (magnification: 200 times) of a core-sheath structured spun yarn in another embodiment of the present invention. FIG. 5 is a weave structure diagram of a fabric in an embodiment of the present invention. FIG. 6 is a weave structure diagram of a fabric in another embodiment of the present invention. FIG. 7 is a schematic perspective view of a wear test device according to an embodiment of the present invention. Figure 8 is a schematic cross-sectional view of the combustion rupture device according to the JIS L 1096 B method.

The multilayered spun yarn of the present invention is a multilayered spun yarn in which the core component fibers are p-aramid fibers and the sheath component fibers include polybenzimidazole fibers and aramid fibers. The aramid fibers of the sheath component fibers include p-aramid fibers and m-aramid fibers, and when the sheath component fibers are 100% by mass, the polybenzimidazole fibers (hereinafter also referred to as "PBI") are 50 to 65% by mass. , p-aramid fibers are blended at a ratio of 18 to 35% by mass, and m-aramid fibers are blended at a ratio of 3 to 18% by mass. As a result, the friction strength, combustion bursting strength, and washing friction discoloration and fading all reach acceptable levels.
The multilayered spun yarn of the present invention may be a bundled spun yarn or a ring spun yarn, but a bundled spun yarn is preferable because it has excellent productivity. In the case of a bundled spun yarn, the surface of the core component fiber is coated with the sheath component fiber, some of the fibers of the sheath component are wrapped around the surface layer, and the remaining fibers are the same as the length of the multilayered spun yarn. The wrapped fibers on the surface layer are twisted in one direction, forming a real twist, and the whole is bundled. In the case of ring-spun yarn, the surface of the core component fiber is covered with the sheath component fiber, and the yarn is actually twisted. Due to this structure, the yarn has high strength, low elongation, and high heat resistance.

When the multilayer structure spun yarn is 100% by mass, the core component fiber is preferably 20 to 40% by mass, and the sheath component fiber is preferably 60 to 80% by mass. Furthermore, when the sheath component fiber is 100% by mass, PBI fibers are 50 to 65% by mass, p-aramid fibers are 18 to 35% by mass, and m-aramid fibers are blended fibers of 3 to 18% by mass. preferable. As a result, the friction strength, combustion bursting strength, and washing friction discoloration and fading all reach acceptable levels.

PBI fiber is a fiber made from a polymer such as 2,2'-(m-phenylen)-5,5'-bibenzimidazole, and has a thermal decomposition temperature of over 600°C, a deflection temperature under load of 410°C, and a glass transition temperature of 410°C. The temperature is 427° C., and the oxygen index (OI) value is 41 or more. This fiber has a strength retention rate of 95% even after being exposed to air at 230°C for two weeks, maintains its fiber performance up to 1000°C in nitrogen, is essentially nonflammable, and has high heat resistance. "Encyclopedia of Textiles," p. 848, Maruzen, March 25, 2002). Products manufactured by PBI Performance Products, Inc. in the United States are known as PBI fibers.

The copolymerized p-aramid fiber used for the core component fiber is manufactured by Teijin Co., Ltd. and has the trade name "Technora". The "Technora" is copolyparaphenylene-3,4'-oxydiphenylene-terephthalamide. These fibers have a tensile strength of 24.5-24.7 cN/dtex, a thermal decomposition onset temperature of about 500° C., and an oxygen index (OI) value of 25.

The m-aramid fibers used for the sheath component fibers are, for example, manufactured by Du Pont in the United States under the trade name "Nomex" (same trade name as manufactured by Toray DuPont in Japan), manufactured by Teijin Corporation under the trade name "Conex", Manufactured by Yantai Taihe Co., Ltd. in China, with product names such as "New Star". The product name "Nomex" has a tensile strength of 3.6 cN/decitex, a thermal decomposition onset temperature of about 400°C, and an oxygen index (OI) value of 29-30.

The p-aramid fibers used for the sheath component fibers are homopolymerized manufactured by Du Pont in the United States under the trade name "Kevlar" (the same trade name is manufactured by Toray DuPont in Japan), and manufactured by Teijin under the trade name "Twaron". (Registered Trademark), There is a product name "Taparan" made by Yantai Taiwa.

The copolymerized p-aramid fiber is manufactured by Teijin and has the trade name "Technora". These fibers have a tensile strength of 20.3-24.7 cN/decitex, a thermal decomposition onset temperature of about 500-550° C., and an oxygen index (OI) value of 25-29. Heat resistance and flame retardancy are high compared to normal fibers.

It is preferable that the core component fiber is a copolymerized p-aramid fiber tension-cut spun yarn, and the sheath component fiber p-aramid fiber is a homopolymerized p-aramid fiber. Copolymer para-aramid has excellent strength, so it is used in the core to increase the strength of the yarn, and monopolymer para-aramid has excellent flame retardant properties, so it is used in the sheath to prevent the yarn from burning. It's set.

The multilayer spun yarn has a structure in which some of the fibers in the sheath component are wrapped fibers in the surface layer, and the wrapped fibers in the surface layer are twisted in one direction and are tied together as a whole. be. Here, the whole refers to fibers other than the tension-cut spun yarn of the core component fibers and the wrapped fibers of the sheath component fibers.

When the multilayer structure spun yarn is 100% by mass, the core component fiber is preferably 20 to 40% by mass, the sheath component fiber is preferably 60 to 80% by mass, and more preferably the core component fiber is 22 to 38% by mass. , the sheath component fiber is 62 to 78% by mass. If the core component fiber is less than 20% by mass, the stretch-cut spun yarn of the core component fiber must be made extremely fine, and it is difficult to produce the stretch-cut spun yarn. Moreover, when the core component fiber exceeds 40% by mass, the covering property of the sheath component fiber becomes low. Further, if the sheath component fiber is less than 60% by mass, the coverage will not be good, and if it exceeds 80% by mass, the fineness of the entire multilayered spun yarn will be undesirable.

The copolymerized p-aramid fiber tension-cut spun yarn of the core component fiber is preferably a tow-broken cut spun yarn. Since the tow-broken stretch-cut fibers are torn fibers, the core component fibers and the sheath component fibers have good affinity, resulting in a multilayered spun yarn with good integrity. This stretch-cut spun yarn may be spun by a direct spinning method in which drafting and twisting is performed in one spinning machine, or it may be made into a slurbar and twisted in two or more steps (purlock method or converter method). good. Preferably, a direct spinning method is used. By using the tension-cut spun yarn, a core-sheath structured spun yarn that can maintain high strength and has excellent integrity with the sheath fibers can be obtained.

The preferred fineness of the tension-cut spun yarn is preferably in the range of 5.56 to 20.0 tex (single yarn in metric count of 50 to 180), more preferably in the range of 6.67 to 16.7 tex (in metric count of single yarn). The range is from 60 to 150 single yarn). If the fineness is within the above range, it will have high strength and will be suitable for heat-resistant protective clothing in terms of feel and the like. Further, the number of twists is preferably 350 to 550 twists/m, more preferably 400 to 500 twists/m for a single yarn with a metric count of 125. If the number of twists is within the above range, the integrity with the coated fibers will be even higher. Further, the preferable fiber length is distributed in the range of 30 to 180 mm, and the average fiber length is in the range of 45 to 150 mm, preferably 50 to 125 mm. Within this range, the power can be maintained even higher.

The PBI fiber of the sheath component fiber is preferably a square cut product. A square cut involves repeating only right-angled cuts of a certain length, so for example, if a 51 mm square cut is made, all fiber lengths will be uniformly 51 mm. The single fiber fineness is preferably in the range of 1 to 5 dtex, more preferably in the range of 1.5 to 4 dtex.

The sheath component fibers are processed into short fiber bundles with the optimal shape and form using a spinning method according to their fineness and fiber length. Here, the hue and the mixing of different types of fibers can be achieved by passing multiple types of fiber bundles (slivers), each of which has a 100% composition, through an intersecting gill box, and then doubling in the subsequent combing or pre-spinning process. and parallelization and symmetry by drafting action. Hereinafter, this method will be referred to as "sliver blending". This method has a high yield and is suitable for high-mix, low-volume production. Here, the mixing of hues and different types of fibers is mainly done by a carding machine during the mixing and carding process. Hereinafter, this method will be referred to as "card blending", and although the yield is low, it is suitable for mass production of small products.

The multilayered spun yarn preferably has a metric count (single yarn) of 28 to 52 (fineness: 357 to 192 decitex). Within this range, protective clothing with good workability can be obtained. The multilayered spun yarn is a double yarn made of two twisted yarns, and the metric count of the double yarn may be 14 to 26 (fineness: 714 to 384 decitex). Using double threads not only makes the surface of the fabric cleaner, but also increases the strength of the fabric.

The twist coefficient K of the double yarn is preferably 100 to 200. However, the coefficient K is calculated using the following formula (1).
K=T/√C...Formula (1)
T: Number of twists of double yarn (twists/m)
C: Double thread count (m/g)

The heat-resistant protective clothing containing the heat-resistant fabric of the present invention is suitable not only as firefighting clothing but also as work clothing for emergency personnel, life-saving personnel, marine relief personnel, the military, workers at oil-related facilities, workers at chemical plants, etc. be. In the case of firefighting suits, it is preferable to use the heat-resistant fabric of the present invention in the outer layer. This is because it has high heat resistance.

Next, the apparatus and method for manufacturing the core-sheath structured yarn of the present invention will be explained using the drawings. FIG. 1 is a perspective view showing the main parts of a binding and spinning device 1 according to an embodiment of the present invention.
(1) Draft process The draft zone 6 of the binding spinning device 1 is composed of a pair of front rollers 2, 2', a pair of second rollers 3 having an apron, a pair of third rollers 4, and a pair of back rollers 5. ing. A sliver 7 made of a blend of polybenzimidazole fiber and aramid fiber serving as a sheath component fiber is passed through a sliver guide 8, supplied from a back roller 5, and drafted in a draft zone 6.
(2) Process of combining the core component fiber and the covering component fiber The p-aramid fiber drag-cut spun yarn 9, which will become the core component fiber, is supplied in front of the front rollers 2, 2' (upstream side) of the draft zone 6, and the sliver is 7 is combined with the drafted fiber bundle.
(3) Spun yarn forming process The combined tension-cut spun yarn 9 of the core component fibers and the fiber bundle of the sheath component fibers are supplied to the spindle 10 which is arranged away from the discharge part of the front rollers 2, 2', A multilayered spun yarn 11 is obtained by false twisting using a swirling flow.
(4) Winding process The obtained multilayer spun yarn 11 passes through the slab catcher 12, is taken up by the friction roller 13, and is driven by the winding drum 14 of the winding section 17 and packaged in a package supported by the cradle arm 15. It is wound up at 16.

FIG. 2 shows a multilayered spun yarn (bound spun yarn) 20 as an example of the present invention. In FIG. 2, the core component fiber 21 is a copolymerized p-aramid fiber yarn that has been tension-cut spun, and the sheath component fiber 25 is a blended fiber of PBI fiber, homopolymerized p-aramid fiber, and m-aramid fiber. The sheath component fibers 25 include inner layer fibers 22 arranged in the longitudinal direction of the multilayer spun yarn, surface layer wrapped fibers 23, and slack fibers 24, and fuzz 26 is also observed. The wound fibers 23 in the surface layer are twisted in one direction and are in the form of a real twist, and are bundled as a whole. As a result, there is little fuzz and the fibers do not fall off even when subjected to abrasion, maintaining a strong thread state. In the above, unidirectional refers to S-twist wrapped fibers or Z-twist wrapped fibers, and does not mean that the twist angles are the same. The S-twist wrapped fiber or the Z-twist wrapped fiber is determined by the direction of the compressed air swirl flow of the spinner of the binding spinning machine. This multilayer structured spun yarn (bound spun yarn) 20 includes core component fibers (stretch-cut spun yarn) 21, inner layer fibers 22 arranged in the length direction of the sheath component fibers 25, and surface layer wrapped fibers 23. It has a three-layer structure. This yarn structure provides high yarn strength.

FIG. 3 is a side view photograph (200x magnification) of a core-sheath structure spun yarn in one embodiment of the present invention, and FIG. 4 is a side view photograph (200x magnification) of a core-sheath structure spun yarn in another embodiment of the present invention. . In each case, there are inner layer fibers arranged in the length direction of the sheath component fibers, surface layer wrapped fibers, and slack fibers, and fluff is also observed.

The protective clothing fabric of the present invention is preferably made by twisting two of the core-sheath spun yarns (single yarn) into a double yarn, and making this into a woven fabric. The reason for using twin yarns is that they have more than twice the strength of single yarns, giving them a cohesive force that prevents yarn breakage during weaving, and also canceling out the uneven thickness of single yarns, creating a beautiful pattern in the fabric. This is to do so. For example, double yarn is manufactured using a twisting machine such as a double twister. The double twister has high productivity because it can twist twice in one rotation of the spindle. However, since there are as many as six abrasion points on the long twisting yarn path, the coating tends to be peeled off and disturbed, exposing the core. Preferably, it is a ring twister with two rubbing points, and most preferably an up twister with two rubbing points and a very short twisting thread path.

The obtained twin yarns are untwisted and used as warp and weft yarns to make a woven fabric. As the textile structure, plain weave, twill weave, satin weave, and other variable weave structures can be used. When knitting, flat knitting, circular knitting, or warp knitting can be used. The organization may be of any type. If air is to be included in the knitted fabric, it is knitted into a double-bound pile fabric. Among the textile structures, the mat weave shown in FIG. 5 is preferred, and this mat weave is a flat + 3/3 mat weave. The plain weave part has a plain structure consisting of eight warp and weft threads, while the 3/3 mat weave part has three warp and weft threads aligned, and this part protrudes from the surface. Another example of mat weave is shown in FIG. This mat weave structure is a flat+2/2 mat weave. The plain weave part has a plain structure consisting of two warp and weft threads, while the 2/2 mat weave part has two warp threads and two weft threads aligned, and this part protrudes from the surface. Such a woven fabric has an anti-slip effect, and even if the plain weave is torn, it will stop at the matte weave, making it difficult to tear. This is called Rip Stop structure because it prevents it from tearing.

The mass per unit (fabric weight) of the protective clothing fabric of the present invention is preferably in the range of 100 to 340 g/m ² . Within the above range, work clothes that are even lighter and more comfortable to wear can be obtained. More preferably, it is in the range of 140 to 300 g/m ² , particularly preferably in the range of 150 to 260 g/m ² .

The multilayer spun yarn of the present invention and the heat-resistant fabric and heat-resistant protective clothing using the same do not necessarily contain antistatic fibers or antistatic fibers. This is because PBI fibers easily absorb moisture and are less likely to be charged with static electricity. If antistatic fibers are mixed according to the customer's request, metal fibers, carbon fibers, fibers kneaded with metal particles or carbon particles, etc. are used. The antistatic fiber is preferably added in an amount of 0.1 to 1% by mass, more preferably 0.3 to 0.7% by mass, based on the spun yarn. Antistatic fiber yarns can also be added during weaving. For example, it is preferable to add 0.1 to 1% by mass of "Beltron" manufactured by KB Seiren, "Kura Carbo" manufactured by Kuraray, carbon fiber, metal fiber, etc.

The present invention will be explained in more detail below using Examples. The present invention is not limited to the following examples.
The measurement methods in Examples and Comparative Examples of the present invention were as follows.
<Abrasion test>
FIG. 7 is a schematic perspective view of an abrasion test apparatus 30 specified in ASTM D 3884-09 Taber method, H-18, according to an embodiment of the present invention. In this abrasion test device 30, a sample cloth 32 is placed on a rotary table 31 and rotated in the direction of the arrow. The rotation speed of the rotary table 31 is 60 rpm, and the

friction wheels

33a and 33b also rotate accordingly.

Friction wheels

33a and 33b are placed above the sample cloth 32 and rotated in opposite directions as shown by the arrows. The total load on the

friction wheels

33a and 33b is 500g. It continues to rotate while sucking up wear particles. The wear mark 34 is annular, with an outer diameter L1 of about 88 mm and an area of about 30 cm ² . Measure the number of rotations until the thread breaks and a hole with a diameter of 1 to 2 mm is created. The passing level is 300 times or more.
<Combustion burst test based on JIS L 1096 B method>
FIG. 8 is a schematic cross-sectional view of a constant velocity elongation type combustion rupture device 35 according to JIS L 1096 B method. A sample cloth 37 with a diameter of 80 mm is attached to the clamp of the sample mounting table 36. The clamp has an inner diameter L2=44 mm. The push rod 38 has a tip radius of 12.5 mm and a diameter L3 of 25 mm. After irradiating the sample cloth with 80 kW of heat for 8 seconds in the ISO 9151 flame exposure test, the tip of the push rod 38 is pressed against the burning part at a pressure rate of 10 cm per minute, and the strength to break through the sample cloth 37 is determined. (N) is measured. A passing level is 140N or higher.
<Washing abrasion discoloration test>
Washing was repeated 10 times according to the method specified in ISO6330 6N-F, and evaluation was made. The evaluation criteria are visually judged on a five-point scale, with the least discolored being grade 5 and the most discolored being grade 1. Level 3 or higher is considered a passing level.
<Other physical properties>
Measured according to JIS or industry standards.

(Examples 1-2, Comparative Examples 1-2)
1. Fiber used (1) Core component fiber The core component fiber is copolymer p-aramid fiber, Teijin Co., Ltd. trade name "Technora" tension-cut spun yarn (number of twists in Z direction 45 times/10cm), yarn fineness 8.0 tex (Metric count: 1/125) (single fiber fineness 1.7 dtex, average fiber length 100 mm, unfinished product (yellow)) was used.
(2) Sheath component fiber The following three types of fibers were blended.
(i) PBI fiber PBI fiber (square cut fiber length 51 mm, fineness 1.7 dtex) manufactured by PBI Performance Products, Inc. in the United States was used.
(ii) Homopolymer p-aramid fiber Manufactured by Yantai Taihe Co., Ltd., China, trade name "Taparan" (square cut fiber length 51 mm, fineness 1.7 dtex, black product) was used.
(iii) M-Aramid fiber: Made by Yantai Taihe Co., Ltd., China, product name "New Star BL3" (square cut fiber length 51 mm, fineness 1.7 dtex) was used.
The above PBI fibers, homopolymer p-aramid fibers, and m-aramid fibers were uniformly mixed at predetermined ratios shown in Table 1.
2. Preparation of spun yarn (1) Bundled spun yarn By the method shown in Figure 1, tension-cut spun yarn of copolymer p-aramid fiber is used as the core component fiber, and PBI fiber, homopolymer p-aramid fiber, and m-aramid fiber are combined. Using the blended fiber bundle (sliver) as the sheath component fiber and using Murata Kikai Co., Ltd.'s product name "No. 870, MURATA VORTEX SPINNER" as shown in Figure 1, a single bound spun yarn was produced at a speed of 300 m/min. did. The metric count of the obtained yarn was No. 40.
(2) Preparation of double yarn Two single bundled spun yarns were twisted using a double twister to form a double yarn. The number of twists was 670 turns/m, and the twist coefficient K was 150.
3. Production of woven fabric Using the double yarns as the warp and weft, a rapier loom was used to fabricate a 2/2 mat weave structure shown in FIG. 6 with a mass of 225 g/m ² and a warp direction yarn density of 216.5 threads/10 cm. , with a weft direction thread density of 206.7 threads/10 cm.
The conditions and results are summarized in Tables 1 and 2.

As is clear from Table 2, in Examples 1 and 2, it was confirmed that the friction strength, combustion bursting strength, and washing friction discoloration and fading were all at acceptable levels.

The heat-resistant protective clothing using the heat-resistant fabric of the present invention is suitable not only as firefighting clothing but also as work clothing for emergency personnel, lifesaving personnel, marine relief personnel, the military, workers at oil-related facilities, workers at chemical plants, etc. It is. In particular, it is possible to provide heat-resistant fabrics and heat-resistant protective clothing that have acceptable levels of friction strength, combustion bursting strength, and washing friction discoloration.

1 Binding spinning device 2, 2' Front roller 3 Second roller 4 Third roller 5 Back roller 6 Draft zone 7 Sliver 8 Sliver guide 9 Tension-cut spun yarn 10 Spindle 11 Multilayer spun yarn 12 Slab catcher 13 Friction roller 14 Friction roller 15 Cradle Arm 16 Package 20 Multilayer structure spun yarn (bound spun yarn)
21 Core component fiber (stretch cut spun yarn)
22 Inner layer fibers of sheath component fibers 23 Wrapped fibers 24 Slack fibers 25 Sheath component fibers 26 Fluff 30 Wear test device 31 Turntable 32

Sample cloths

33a, 33b Friction ring 34 Wear marks

Claims

The core component fiber is a p-aramid fiber stretch-cut yarn, and the sheath component fiber is a multilayer spun yarn containing polybenzimidazole fiber and aramid fiber,
The aramid fibers of the sheath component fibers include p-aramid fibers and m-aramid fibers,
When the sheath component fibers are 100% by mass, polybenzimidazole fibers are blended in a proportion of 50 to 65% by mass, p-aramid fibers in 18 to 35% by mass, and m-aramid fibers in a proportion of 3 to 18% by mass. A multi-layered spun yarn characterized by:
Some of the fibers of the sheath component fibers are wound fibers in the surface layer, and the remaining fibers are arranged in the length direction of the multilayered spun yarn,
2. The multilayered spun yarn according to claim 1, wherein the wound fibers in the surface layer are twisted in one direction, and are bundled as a whole.
The multilayered spun yarn according to claim 1 or 2, wherein the core component fiber is a copolymerized p-aramid fiber drag-cut yarn, and the sheath component p-aramid fiber is a homopolymerized p-aramid fiber.
The multilayer according to any one of claims 1 to 3, wherein when the multilayer structured spun yarn is 100% by mass, the core component fiber is 20 to 40% by mass, and the sheath component fiber is 60 to 80% by mass. Structural spun yarn.
The multilayered spun yarn according to any one of claims 1 to 4, wherein the multilayered spun yarn has a metric count of 28 to 52 (fineness: 357 to 192 decitex).
The multilayer according to any one of claims 1 to 5, wherein the multilayer structured spun yarn is a double yarn made of two twisted yarns, and the metric count of the double yarn is 14 to 26 (fineness: 714 to 384 decitex). Structural spun yarn.
The multilayered spun yarn according to claim 6, wherein the twist coefficient K of the double yarn is 100 to 200.
However, the coefficient K is calculated using the following formula (1).
K=T/√C...Formula (1)
T: Number of twists of double yarn (twists/m)
C: Double thread count (m/g)
A method for producing a multilayered spun yarn according to any one of claims 1 to 7, comprising:
A sliver made of a blend of polybenzimidazole fiber and aramid fiber, which will become the sheath component fiber, is supplied to the draft zone and drafted.
Supplying a p-aramid fiber tension-cut thread serving as a core component fiber to the front roller of the draft zone to form a fiber bundle that is combined with the sliver;
A method for producing a multilayered spun yarn, characterized in that the fiber bundle is supplied to a spindle disposed away from the discharge part of the front roller, false twisted by swirling flow, and then wound.
A heat-resistant fabric comprising the multilayer spun yarn according to any one of claims 1 to 7.
The heat-resistant fabric according to claim 9, wherein the heat-resistant fabric is a fabric that combines a plain weave structure and a 2/2 or 3/3 matte weave structure.
Heat-resistant protective clothing comprising the heat-resistant fabric according to claim 9 or 10.