Antistatic spun yarn

Abstract

To provide an antistatic spun yarn having excellent antistatic properties for removing static electricity and excellent handleability in a yarn-making process, a weaving process, a dyeing process, a sewing process, etc.SOLUTION: The antistatic spun yarns contain 5 to 30% by mass of conductive short fibers based on 100% by mass of all fibers constituting the antistatic spun yarns, and the conductive short fibers have a fiber length of 25 to 55mm and a frictional voltage resistance of 800 or less in both warp and weft directions.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to an antistatic spun yarn that contains a specific amount of conductive short fibers having a fiber length of 25 to 55 mm and has excellent static electricity removal performance. [Background technology]

[0002] Among uniforms, work clothes worn in factories in particular require explosion-proof properties from a safety standpoint, and anti-static properties are also required to prevent accidents caused by static electricity adhering to the clothing.

[0003] Recently, antistatic properties are also being required for the white coats worn by doctors and nurses, for example, in consideration of the impact on medical electronic devices. This is because if static electricity attached to the white coat affects medical electronic devices, it could have a significant impact on the health and life of patients receiving treatment using medical electronic devices.

[0004] To impart antistatic properties, it is generally sufficient to weave conductive filament fibers (conductive filament fibers) into a woven fabric. However, because conductive filament fibers have low strength, using them alone results in frequent thread breakage during weaving, making weaving undesirable. Therefore, by combining them with other fibers and processing them into conductive composite yarns, thread breakage during weaving is prevented and weaving properties are improved. For example, a yarn in which another fiber is wound around a conductive filament fiber is known as such a conductive composite yarn (for example, Patent Document 1).

[0005] The conductive composite yarn described in Patent Document 1 was able to improve weaving properties to a certain extent, but had the problem that the conductive filament fibers were prone to breakage during the process of producing the conductive composite yarn, resulting in a decrease in conductive performance at the locations where the conductive filaments were broken.In addition, the appearance of the fabric after the weaving, dyeing, sewing, and other processes was poor, and problems caused by breakage of the conductive filament fibers could not be fully improved. Furthermore, there is room for improvement in the anti-static performance for removing static electricity. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 3-269131 Summary of the Invention [Problem to be solved by the invention]

[0007] The present invention is intended to solve the above-mentioned problems, and has as its technical object to provide an antistatic spun yarn that has excellent antistatic properties for removing static electricity and also has excellent handleability in spinning, weaving, dyeing, sewing, and other processes. [Means for solving the problem]

[0008] As a result of research conducted by the inventor to solve the above-mentioned problems, it was discovered that while conventionally conductive filament fibers have been used as conductive threads to achieve antistatic properties in fabrics, by making a spun yarn containing a specific amount of conductive short fibers of a specific fiber length, deterioration in processability due to thread breakage of the conductive filament fibers can be prevented and, further, antistatic performance can be improved, leading to the present invention.

[0009] That is, the present invention is summarized as follows (1) to (3). (1) An antistatic spun yarn containing conductive staple fibers made of a thermoplastic resin containing a conductive substance, wherein when the mass of all fibers constituting the antistatic spun yarn is taken as 100 mass%, the conductive staple fibers account for 5 to 30 mass%, and the fiber length of the conductive staple fibers is 25 to 55 mm; Antistatic spun yarn with a friction withstand voltage of 800 or less in both the warp and weft directions. The frictional withstand voltage is measured using antistatic spun yarn that has been cylindrically knitted and then scoured under the following conditions: 80°C x 20 minutes, Sunmol FL 1g / l, bath ratio 1:50, using wool as an abrasive cloth according to Method B of JIS L 1094: Test method for electrostatic properties of woven and knitted fabrics. (2) An antistatic spun yarn according to (1), which contains polyester staple fibers and cellulose staple fibers as fibers other than the conductive staple fibers, and the polyester staple fibers are contained in an amount of 20 to 40% by mass and the cellulose staple fibers are contained in an amount of 40 to 65% by mass. (3) A woven or knitted fabric containing the antistatic spun yarn described in (1). [Effects of the Invention]

[0010] The antistatic spun yarn of the present invention is resistant to yarn breakage during spinning, weaving, dyeing, sewing and other processes, has excellent handleability, and also has excellent antistatic properties including excellent static elimination performance. Therefore, the woven or knitted fabric obtained using the antistatic spun yarn of the present invention can be suitably used in uniform applications where explosion-proof properties are particularly required. DETAILED DESCRIPTION OF THE INVENTION

[0011] The present invention will be described in detail below. The antistatic spun yarn of the present invention contains conductive short fibers made of a thermoplastic resin containing a conductive substance.

[0012] First, the conductive staple fiber made of a thermoplastic resin containing a conductive substance will be described. The conductive staple fiber constituting the antistatic spun yarn in the present invention is preferably a composite fiber made of a non-conductive component made of a thermoplastic resin and a conductive component made of a thermoplastic resin containing conductive particles, and in a cross section of the conductive staple fiber cut perpendicular to the longitudinal direction of the fiber, it is preferable that the conductive component portion is present in the non-conductive component and that at least a part of the conductive component is exposed on the fiber surface.

[0013] As the thermoplastic resin that constitutes the conductive component and non-conductive component of the conductive short fiber, melt-spinnable resins such as polyamide, polyester, and polyolefin can be used, but polyester is preferred among them, and the non-conductive component is preferably a polyester resin in which ethylene terephthalate repeating units account for 50 mol % or more, and more preferably 80 mol % or more of all repeating units constituting the polyester resin. Copolymerization components other than ethylene terephthalate include isophthalic acid and adipic acid. Examples include: On the other hand, the conductive component is preferably a resin composition containing 20 to 35 mass % of conductive particles in polybutylene terephthalate.

[0014] Examples of conductive particles used in the present invention include conductive carbon black, metal powders (silver, nickel, copper, iron, tin, or alloys thereof), and metal compounds such as copper sulfide, copper iodide, zinc sulfide, and cadmium sulfide. Other examples include conductive particles obtained by adding a small amount of antimony oxide to tin oxide or a small amount of aluminum oxide to zinc oxide. Furthermore, conductive particles obtained by coating the surface of titanium oxide with tin oxide and then mixing and baking antimony oxide can also be used. Among these, conductive carbon black (e.g., acetylene black, ketjen black, etc.) is preferred from the viewpoint of improving the performance of the conductive fiber and being less likely to inhibit the fluidity of the polymer than metal particles.

[0015] The antistatic spun yarn uses conductive staple fibers as part of the staple fibers that make up the antistatic spun yarn, and the conductive staple fibers have a fiber length of 20 to 55 mm, preferably 25 to 52 mm, and more preferably 25 to 45 mm. If the fiber length is less than 25 mm, the single filament strength of the antistatic spun yarn will decrease, resulting in poor weaving and knitting properties, and the increased number of fluffs will result in poor fabric quality, such as pilling.

[0016] On the other hand, if the fiber length exceeds 55 mm, the number of conductive short fiber ends per unit length of the antistatic spun yarn decreases, resulting in a decrease in the antistatic effect (increase in frictional withstand voltage).In addition, the difference in fiber length from other fibers such as cellulose short fibers tends to increase yarn unevenness, and twist unevenness can cause partial reductions in single yarn strength and deterioration of fabric quality.

[0017] The antistatic spun yarn of the present invention is characterized in that it uses short fiber-type conductive fibers rather than filament-type fibers, but the use of short fiber-type conductive yarns results in a lower frictional withstand voltage and superior antistatic properties. This is presumably because corona discharge of conductive materials occurs at the electrode ends, i.e., at both ends of the conductive fibers, and corona discharge is more likely to occur when the conductive fibers are in the form of short fibers than when the conductive fibers are in the form of filaments, due to the greater amount of both ends. Therefore, it is thought that a spun yarn containing conductive fibers in the form of short fibers, which have many electrode ends, will have a lower frictional withstand voltage and will have excellent antistatic properties.

[0018] The antistatic spun yarn of the present invention preferably contains polyester staple fibers and cellulose staple fibers as fibers other than the conductive staple fibers that constitute the antistatic spun yarn. First, polyester staple fibers will be described. The polyester resin constituting the polyester staple fibers is preferably a polyester resin in which ethylene terephthalate repeating units account for 50 mol % or more, more preferably 80 mol % or more, and even more preferably 95 mol % or more of all repeating units constituting the polyester resin. Examples of copolymerization components other than ethylene terephthalate include isophthalic acid and adipic acid.

[0019] The fiber length of the polyester short fibers is 25 to 55 mm, preferably 25 to 52 mm, and more preferably 25 to 45 mm. If the fiber length is less than 25 mm, the single filament strength of the antistatic spun yarn will decrease, resulting in poor weaving and knitting properties, and the increased number of fluffs will result in poor fabric quality, such as pilling. On the other hand, if the fiber length exceeds 55 mm, the difference in fiber length from other fibers such as short cellulose fibers tends to increase yarn unevenness, resulting in partial reduction in single yarn strength due to uneven twist and deterioration of fabric quality.

[0020] The cellulose staple fibers in the present invention include plant fibers such as cotton and hemp, regenerated cellulose fibers such as viscose rayon and Tencel (modal, lyocell), acetate fibers, etc. Among these, cotton is preferred, and the fiber length is preferably 55 mm or less.

[0021] When the mass of all fibers constituting the antistatic spun yarn is taken as 100 mass %, the content of the conductive short fibers is 5 to 30 mass %, and preferably 10 to 25 mass %. The content of polyester short fibers is preferably 20 to 40% by mass, and the content of cellulose short fibers is preferably 40 to 65% by mass. If the content of conductive short fibers in the antistatic spun yarn is less than 5% by mass, the antistatic spun yarn will have poor static electricity removal performance, while if the content of conductive short fibers exceeds 30% by mass, yarn breakage will be more likely to occur during the spinning, weaving, dyeing, sewing, and other processes.

[0022] In order for the antistatic spun yarn of the present invention to have excellent static electricity removal performance, the frictional withstand voltage must be 800 or less in both the warp and weft directions, and in particular, 600 or less in both the warp and weft directions is preferable, and 400 or less in both the warp and weft directions is even more preferable. In the present invention, the frictional withstand voltage is measured by using conductive spun yarn only, which is cylindrically knitted, and then scouring it under the following conditions: 80°C x 20 minutes, 1 g / l of Sunmol FL, and a bath ratio of 1:50, in accordance with JIS L 1094: Test method for electrostatic properties of woven and knitted fabrics, Method B, using wool as an abrasive cloth.

[0023] The antistatic spun yarn of the present invention may take the form of a blended yarn obtained from a sliver containing conductive staple fibers, polyester staple fibers, and cellulose staple fibers; a sheath-core (two-layer) spun yarn having a sliver containing conductive staple fibers and polyester staple fibers as the core and cellulose staple fibers as the sheath; a sheath-core (two-layer) spun yarn having a sliver containing polyester staple fibers as the core and conductive staple fibers and cellulose staple fibers as the sheath; and a spun twisted yarn consisting of a roving containing conductive staple fibers, polyester staple fibers, and cellulose staple fibers on one side and a roving containing polyester staple fibers and cellulose staple fibers on the other side.

[0024] In the antistatic spun yarn of the present invention, it is preferable to use conductive carbon black for the conductive particles from the viewpoint of improving the conductive performance of the conductive short fibers, but since conductive carbon black is black, the conductive short fibers also turn black. Therefore, in the case of the blended yarn described above, there will be variations in the ratio of the number of filaments of the conductive short fibers that make up the blended yarn present in the longitudinal direction of the spun yarn, which will tend to result in a black spun yarn with color spots in the longitudinal direction of the spun yarn. In order to reduce yarn unevenness in the longitudinal direction of the spun yarn, it is important to reduce variation in the composition ratio of the black conductive staple fibers in the longitudinal direction of the spun yarn, and it is preferable to use a core-sheath (two-layer structure) spun yarn or a spun twisted yarn in which the above-mentioned conductive staple fibers are arranged in the core.

[0025] The method for producing the antistatic spun yarn of the present invention will now be described. The antistatic spun yarn of the present invention can be obtained by preparing conductive short fibers by cutting conductive filaments having a predetermined electrical resistance value to a predetermined fiber length, and then subjecting these conductive short fibers to a known spinning process.

[0026] Conductive filaments can be obtained by melt spinning using conventional methods. Specifically, when ethylene terephthalate is the main repeating unit and the acid component is 100 mol%, a polyester resin containing 1 to 15 mol% isophthalic acid (IPA) as a copolymerization component is used for the core, and a PBT resin containing 20 to 35 mass% carbon black is used for the sheath. These materials are kneaded and melted using a conventional conjugate spinning device, for example, an extruder, and extruded through a core-sheath spinneret to perform melt spinning to obtain undrawn yarns. The wound undrawn yarn is stretched 1.2 to 2.0 times while heated at 50 to 100°C, and then heat-treated at 130 to 150°C before being wound up to obtain conductive filaments.

[0027] A plurality of the obtained conductive filaments are bundled together to form a tow of conductive filaments. The tow of conductive filaments is crimped by gear crimping or the like, and a spinning oil is applied, followed by drying. The tow of crimped and spinning-oiled conductive filaments is cut to a predetermined length with a cutter and then opened to obtain conductive staple fibers for spinning.

[0028] The resulting conductive staple fibers are mixed with other fibers and fed into a punching machine to obtain a sheet-like wrap. The resulting wrap is then fed into a carding machine and carded into a web, which is then spun and bundled and pressed with a calendar roll to obtain a carded sliver containing the conductive staple fibers.

[0029] Next, in the drawing process, a card sliver containing only conductive short fibers or a plurality of slivers consisting of fibers other than conductive short fibers are combined and repeatedly drawn to obtain a sliver M containing a predetermined amount of conductive short fibers.

[0030] Next, in the roving step, the sliver M containing the conductive short fibers is supplied, stretched between rollers, and then wound up while being twisted to obtain a roving containing the conductive short fibers. The roving containing the conductive staple fibers is further drawn and twisted in a predetermined twisting direction in a spinning process to obtain an antistatic spun yarn containing the conductive staple fibers of the present invention. The antistatic spun yarn obtained after the spinning process is wound up to a predetermined weight and length in the next finishing process.

[0031] At this time, residual defects (neps, slub, fine threads, waste threads, etc.) contained in the spun yarn during the finishing process are usually checked by running the yarn between defect detection sensors before winding. The defect detection sensor detects residual defects in a set specific range, and yarns that do not contain defects are joined together while being wound, thereby obtaining spun yarn from which residual defects in the specific range have been removed.

[0032] The woven or knitted fabric of the present invention is a woven or knitted fabric that at least partially contains the antistatic spun yarn of the present invention. The content of the antistatic spun yarn in the woven or knitted fabric of the present invention is preferably 0.03% by mass or more, more preferably 0.15% by mass or more. The upper limit of the content of the antistatic spun yarn varies depending on the use of the woven or knitted fabric, but for example, for clothing use, it is preferably approximately 30% by mass or less. The woven or knitted fabric of the present invention can be used, for example, for clothing applications (such as work clothes, dustproof clothing, and clean room clothing) or industrial materials applications (such as gloves for smartphones, smart textiles, and charging brushes for electronic devices).

[0033] The woven or knitted fabric of the present invention is not particularly limited in terms of weave, but it is preferable from the viewpoint of antistatic performance to use a weave in which the antistatic spun yarn is exposed on the surface of the fabric or to use antistatic spun yarn for both the warp and weft. In the case of woven fabrics, examples include plain weave, twill weave, satin weave, dobby weave, and double weave, and it is preferable to use the antistatic spun yarn of the present invention for either the warp or weft or both, and to use the antistatic spun yarn so that it is arranged in the woven fabric at intervals of 10 mm or less, preferably at intervals of 8 to 1 mm. In the case of knitted fabrics, any of circular knitting, weft knitting, and warp knitting may be used. In the case of circular knitting and weft knitting, it is preferable to insert the antistatic spun yarn of the present invention at intervals of 10 mm or less, and it is preferable to use it so that it is arranged at intervals of 8 to 1 mm. [Example]

[0034] The present invention will now be described in more detail with reference to examples, in which various property values ​​and evaluations are as follows:

[0035] [Friction voltage resistance (antistatic)] Measurement was carried out by the above-mentioned method. After knitting was carried out on a cylindrical knitting machine, the obtained knitted fabric was subjected to a scouring treatment to prepare a measurement sample for evaluating antistatic properties. The cylindrical knitting machine used had a bobbin diameter of 40 inches and a gauge of 20. The knitting tension, stitch count, etc. were adjusted appropriately, and the fabric was knitted in a jersey weave. The refining treatment conditions were: treatment temperature x time: 80°C x 20 minutes, prescription: Sunmol FL 1g / l, bath ratio 1:50.

[0036] The cellulose staple fibers (cotton fibers) and polyester staple fibers used in the examples were as follows: [Cotton fiber] Australian cotton, ANDY medium-length cotton class (effective fiber length 1 1 / 8 inch (29.4 mm)) [Polyester staple fiber] Indorama Polyester Industries PCL. 100% Polyester Staple Fiber 1.2D x 38mm Semi-Dull Raw White, Fiber Length: 38mm, Fineness: 1.2 Denier

[0037] Example 1 (conductive filament) Polyester resin in the core: A slurry of terephthalic acid (TPA) and ethylene glycol (EG) was supplied to an esterification reactor and reacted at a temperature of 250°C and a pressure of 50 hPa to obtain a reaction product with an esterification reaction rate of 95%. A slurry of isophthalic acid (IPA) and ethylene glycol was charged into another esterification reactor, and the esterification reaction was carried out at a temperature of 200° C. for 3 hours to obtain a reaction solution of isophthalic acid and ethylene glycol. The reaction product of TPA and EG, the reaction solution of isophthalic acid and ethylene glycol, and the polymerization catalyst were added, and the reactor was decompressed to carry out a melt polymerization reaction, producing a copolymer polyester resin (copolymerized with 8 mol% IPA as the acid component, melting point 234°C, melt viscosity 1340 dPa s -1 ) was obtained. Polyester resin for the sheath: Polybutylene terephthalate (PBT) mixed with 25% conductive carbon black by mass, melting point 223°C, melt viscosity 1450 dPa·s -1 Resin of 1000 kJ / g was obtained.

[0038] The above-mentioned polyester resin for the core and the polyester resin for the sheath were prepared and fed into a composite spinning apparatus. These resins were melt-spun using a spinneret designed to produce a fiber with a cross-sectional shape as shown in Figure 1. The area ratio of the core to the sheath (core / sheath) was 85 / 15, and the sheath was arranged to cover the entire surface of the core. The spinning temperature was 270°C. The melt-spun yarn from the spinneret nozzle was cooled by blowing cooling air (temperature 24°C) at a position 120 mm from the bottom of the spinneret nozzle, and after bundling and oiling, it was taken up at a speed of 2700 m / min on a take-up roller to obtain a partially undrawn yarn. A heater plate at 140°C was placed between the first roller (temperature 90°C) and the second roller (room temperature). The resulting partially undrawn yarn was stretched at a draw ratio of 1.7 while being heat-treated between the first and second rollers, and a conductive filament (28 dtex / 6 f) was wound up.

[0039] (Conductive short fibers) A tow with a total fineness of 11,200 dtex was prepared by repeatedly bundling multiple conductive filaments described above using an RT winder. After crimping this tow, it was passed through an oil bath for applying spinning oil and then dried in a hot air dryer to obtain a tow that had been crimped and treated with spinning oil. Finally, this tow that had been crimped and treated with spinning oil was cut while being wound with a rotary cutter to obtain conductive staple fibers with a length of 38 mm.

[0040] The measured physical properties of the raw cotton of the conductive short fibers obtained above were as follows. Apparent fineness: 5.32 dtex, average fiber length: 39.4 mm, tensile strength: 3.01 cN / dtex, elongation: 79.5%, number of crimps: 7.7 / 25 mm, crimp rate: 7.3%, dry heat dimensional change: -5.3%, oil extractables: 0.62%. Here, the measurement methods for each raw cotton physical property value were in accordance with JIS L 1015, with apparent fineness measured using correct fineness method A, average fiber length measured using method C, tensile strength and elongation measured using a testing machine: constant speed extension type, grip spacing: 20 mm, and pulling speed: 20 mm / min, dry heat dimensional change measured at 180°C for 15 minutes, and oil extract measured using diethyl ether as the extracted oil.

[0041] (Antistatic spun yarn) The conductive staple fibers obtained above were fed into a punching machine and passed through each punching process to obtain a sheet-like wrap made of the conductive staple fibers. The wrap made of this conductive short fiber was fed into a carding machine, and after undergoing a carding process in the carding machine, the web was spun, bundled, and pressed with a calendar roll to obtain a carded sliver of 300 gr / 6 yd (hereinafter, gr: 1 grain = 0.06479891 grams, yd: 1 yard = 0.9144 meters). In addition, a 300 gr / 6 yd card sliver made of cotton fibers and a 300 gr / 6 yd card sliver made of polyester staple fibers were prepared in the same manner.

[0042] Next, using each of the obtained card slivers consisting of conductive staple fibers, cotton fibers, and polyester staple fibers, the number of each sliver fed into the drawing frame was adjusted, and the drawing process was repeated twice to obtain a drawn sliver containing 15% by mass of conductive staple fibers, 30% by mass of polyester staple fibers, and 55% by mass of cotton fibers. The obtained drawn sliver was fed into a roving frame, stretched 7.4 times, and then twisted in the Z direction to obtain a roving containing conductive short fibers with a roving mass of 270 gr / 30 yd and a twist number of 0.96 times / 2.54 cm. This roving was passed through the trumpet (guide) of a spinning frame, passed through the back roller, apron, and front roller in that order, and stretched 37.2 times. After that, it was twisted in the Z direction to a twist number of 22.2 times per 2.54 cm, and an antistatic spun yarn of 34 count (British cotton count) was obtained.

[0043] Example 2 Using card slivers consisting of the same conductive staple fibers, cotton fibers, and polyester staple fibers as in Example 1, the number of slivers fed into the drawing frame was adjusted, and the drawing process was repeated twice to obtain a drawn sliver containing 25% by mass of conductive staple fibers, 30% by mass of polyester staple fibers, and 45% by mass of cotton fibers. Except for using this drawing sliver, the same roving and fine spinning processes as in Example 1 were carried out to obtain an antistatic spun yarn having the same British cotton count as in Example 1.

[0044] Example 3 Using card slivers consisting of the same conductive staple fibers, cotton fibers, and polyester staple fibers as in Example 1, the number of slivers fed into the drawing machine was adjusted, and the drawing process was repeated twice to obtain a drawn sliver S1 containing 30% by mass of conductive staple fibers, 25% by mass of polyester staple fibers, and 45% by mass of cotton fibers. The obtained drawn sliver S1 was fed into a roving frame, stretched 7.4 times, and then twisted in the Z direction to obtain a roving L1 containing conductive short fibers with a roving mass of 135 gr / 30 yd and a twist number of 1.36 times / 2.54 cm. Similarly, using card slivers made of the same cotton fibers and polyester staple fibers as in Example 1, the number of slivers fed into the drawing frame was adjusted, and the drawing process was repeated twice to obtain a drawn sliver S2 containing 35% by mass of polyester staple fibers and 65% by mass of cotton fibers. The obtained drawn sliver S2 was fed into a roving frame, stretched 7.4 times, and then twisted in the Z direction to obtain a roving L2 containing no conductive short fibers, with a roving mass of 135 gr / 30 yd and a twist number of 1.36 times / 2.54 cm. The roving L1 containing the conductive staple fibers and the roving L2 not containing the conductive staple fibers were simultaneously fed to the trumpet (guide) of a spinning frame, passed through the back roller, apron, and front roller in that order, and stretched 37.2 times. After that, the rovings were combined while being twisted in the Z direction to give a twist number of 22.2 turns / 2.54 cm, to obtain an antistatic spun yarn of 34 count (British cotton count) containing 15% by mass of conductive staple fibers, 30% by mass of polyester staple fibers, and 55% by mass of cotton fibers.

[0045] Comparative Example 1 The conductive filament described in Example 1 and a polyester / cotton blended yarn (British cotton count: 34) containing 65% by mass of polyester staple fiber and 35% by mass of cotton fiber were prepared. This conductive filament and polyester / cotton blended yarn were used to doubling the yarn in a doubling machine, and then twisted in the S direction in a twisting machine so that the final twist number was 15.5 times / 2.54 cm, resulting in a doubled-twisted yarn containing 14% by mass of conductive filament, 56% by mass of polyester staple fiber, and 30% by mass of cotton fiber.

[0046] Comparative Example 2 Using the same card sliver made of cotton fiber and card sliver made of polyester staple fiber as in Example 1, the number of slivers fed into the drawing frame was adjusted, and the drawing process was repeated twice to obtain a drawn sliver containing 30% by mass of polyester staple fiber and 70% by mass of cotton fiber. Except for using this drawing sliver, the same roving and fine spinning processes as in Example 1 were carried out to obtain a spun yarn containing no conductive short fibers and having the same British cotton count as in Example 1.

[0047] Table 1 shows the raw cotton compositions of the spun yarns obtained in Examples 1 to 3 and Comparative Examples 1 and 2, and the measurement results of the frictional withstand voltage.

[0048] [Table 1]

[0049] As is clear from Table 1, the antistatic spun yarns obtained in Examples 1 to 3 contained a specified mass percent of conductive short fibers and had excellent antistatic properties because their frictional withstand voltage was within the range specified in the present invention.

[0050] The effects of the present invention will be explained individually using each example and comparative example. Comparing Example 1 and Comparative Example 1, the conductive fiber used in Comparative Example 1 is in the form of a filament, while the conductive fiber used in Example 1 is in the form of a short fiber, and the composition ratio of the conductive fiber is also similar. Furthermore, the conductive fiber used in Example 1 and Comparative Example 1 is crimped to form the short fiber in Example 1, but the same original conductive filament is used, and the composition as a single filament is the same.

[0051] The plied and twisted yarn of Comparative Example 1 did not satisfy the frictional withstand voltage specified in the present invention and had poor antistatic properties. The antistatic spun yarn of Example 1 has excellent antistatic properties because it contains conductive fibers in the form of staple fibers, but this is because corona discharge of conductive materials occurs at the start of the electrode, that is, at both ends of the conductive fibers, and therefore Example 1, which contains conductive fibers in the form of staple fibers, has a greater amount of conductive fibers at both ends than Comparative Example 1, which contains conductive fibers in the form of filaments, making the corona discharge effect more likely to occur, resulting in a lower frictional withstand voltage and excellent antistatic properties.

[0052] Comparing Example 2 with Examples 1 and 3, Example 2 had a higher proportion of conductive short fibers than Examples 1 and 3, and therefore had an even lower frictional withstand voltage than Examples 1 and 3 and was excellent in antistatic properties. Furthermore, the spun yarn of Example 3 was made into a spinned twisted yarn in consideration of the occurrence of color unevenness due to the conductive short fibers, and therefore had a superior color tone with no yarn unevenness in the longitudinal direction of the spun yarn compared to the spun yarns of Examples 1 and 2.

[0053] Comparative Example 2 did not contain conductive short fibers, and therefore had a high friction withstand voltage and poor antistatic properties.

Claims

1. An antistatic spun yarn containing conductive short fibers made of a thermoplastic resin containing a conductive substance, When the mass of all fibers constituting the antistatic spun yarn is 100 mass%, the conductive short fibers are 5 to 30 mass%, The conductive short fibers have a fiber length of 25 to 55 mm, Antistatic spun yarn with a friction withstand voltage of 800 or less in both warp and weft directions. The frictional withstand voltage is measured by cylindrically knitting only using antistatic spun yarn, scouring the cylindrical knitted fabric under the following conditions: 80°C x 20 minutes, 1 g / l of Sunmol FL, bath ratio 1:50, and using wool as an abrasive cloth according to Method B of JIS L 1094: Test method for electrostatic properties of woven and knitted fabrics.

2. The antistatic spun yarn according to claim 1, wherein the fibers other than the conductive staple fibers constituting the antistatic spun yarn include polyester staple fibers and cellulose staple fibers, and the polyester staple fibers are contained in an amount of 20 to 40 mass % and the cellulose staple fibers are contained in an amount of 40 to 65 mass %.

3. A woven or knitted fabric comprising the antistatic spun yarn according to claim 1.

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