Spun twisted yarn and its manufacturing method

Abstract

To provide a spun yarn made of cotton fiber, which exhibits high stretchability after alkali treatment (mercerization) and also has excellent stretch-back properties. [Solution] A spun yarn made of cotton fibers, the spun yarn being a single yarn, having an elongation of 12% or more after immersion in an alkaline solution at 20°C for 2 minutes under no tension, and an elongation recovery of 61% or more after immersion in an alkaline solution at 20°C for 2 minutes under no tension. The spun yarn contains cotton fiber A and cotton fiber B having different average finenesses in micronaire fineness, and is preferably obtained by spun-twisting a roving made of cotton fiber A with a roving made of cotton fiber B, and has a twist coefficient K of 4.2 to 8.0.

Description

[Technical Field]

[0001] The present invention relates to a spun cross-twisted yarn that exhibits excellent stretchability and stretch-back properties after alkali treatment, and to a woven or knitted fabric using the spun cross-twisted yarn. [Background technology]

[0002] Cotton-containing spun yarns have poor stretchability when made into woven or knitted fabrics, and various improvements have been proposed, including the widely known method of using cotton spun yarns in combination with polyurethane elastic fibers. However, polyurethane elastic fibers have different dyeability from cotton spun yarns, which means that defects are likely to occur during dyeing, and there are problems such as poor texture and lightfastness.

[0003] Therefore, various means for imparting stretchability to woven or knitted fabrics using only cotton spun yarn have been disclosed. For example, Patent Document 1 proposes a core-sheath composite yarn in which a 100% cotton hard-twist spun yarn with a twist coefficient K of 5 or more is used as the core yarn and a 100% cotton sheath yarn is wrapped around the surface of this core yarn. It describes that the hard-twist spun core yarn shrinks more than the sheath yarn when heated by heat setting or hot water heating, thereby imparting stretchability to the composite yarn. It also proposes that a spun-twisted composite yarn can be obtained by spun-twisting a 100% cotton hard-twist spun yarn with a twist coefficient K of 5 or more with staple roving, thereby achieving excellent elasticity. In other words, Patent Document 1 discloses a spun yarn made by combining yarns with different twist strengths, and the difference in shrinkage allows the yarn to be stretchable.

[0004] However, in the case of sheath-core composite yarns or two-ply yarns, the spun single yarn itself is twisted (first twist in the case of ply yarns). Therefore, compared to the case of spun ply yarns, even if the fiber raw material, count, and twist number (corresponding to the twist number during spinning in the case of spun ply yarns, and the twist number during final twist in the case of two-ply yarns) are the same, the resulting woven or knitted fabric tends to have a higher amount of fuzz and inferior texture, such as a fluffy feel and bulkiness. Furthermore, in the spun ply composite yarn of Patent Document 1, additional twist is added during the spun ply and staple roving spinning process. The twist coefficient of the strong twist spun yarn in the composite yarn is very high, making it difficult to shrink. Therefore, the stretchability (extensibility) is not fully exhibited, and the stretch-back property (stretch recovery) is also insufficient. Furthermore, the need to prepare a strong twist spun yarn poses productivity problems.

[0005] Furthermore, spun yarns and woven / knitted fabrics containing cotton fibers are often subjected to mercerization (alkali treatment) to improve the texture, luster, and dyeability. Mercerization involves treating woven / knitted fabrics containing cotton fibers with caustic soda to swell the cross-sections of the cotton fibers and change them to a rounded state. During this process, tension is usually applied in the warp and weft directions to prevent excessive shrinkage of the woven / knitted fabric due to shrinkage caused by the swelling of the cotton fibers. However, taking into account the characteristics of cotton fibers and the implementation of mercerization, a spun yarn that provides excellent stretchability and stretch-back properties in the processed spun yarns and woven / knitted fabrics has not yet been proposed. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2005-146472 Summary of the Invention [Problem to be solved by the invention]

[0007] Therefore, an object of the present invention is to solve the above problems and to obtain a spun yarn made of cotton fibers that exhibits high stretchability after alkali treatment (mercerization) and also has excellent stretch-back properties. [Means for solving the problem]

[0008] As a result of extensive research, the present inventors have found that by using cotton fiber A and cotton fiber B, which have different average finenesses in Micronaire fineness, to prepare a roving made of cotton fiber A and a roving made of cotton fiber B, and then spinning and twisting these rovings, the resulting spun and twisted yarn exhibits high stretchability and stretch-back properties after alkali treatment, and has these excellent properties even without using a hard twist spun yarn, thereby arriving at the present invention.

[0009] That is, the present invention provides the following A to E. (i) A spun yarn made of cotton fibers, the spun yarn being a single yarn, having an elongation rate of 12% or more after immersion in an alkaline solution at 20°C for 2 minutes under no tension, and an elongation recovery rate of 61% or more after immersion in an alkaline solution at 20°C for 2 minutes under no tension. (b) A spun cross-twisted yarn according to (a), which contains cotton fiber A and cotton fiber B having different average finenesses in micronaire fineness, and is obtained by cross-twisting a roving made of cotton fiber A with a roving made of cotton fiber B, and has a twist coefficient K of 4.2 to 8.0. (c) The spun twisted yarn according to (b), wherein the difference in average micronaire fineness between cotton fiber A and cotton fiber B is 0.5 or more. A woven or knitted fabric comprising the spun twisted yarn according to any one of (ii), (iii), (iv), (v), and (iii). A method for producing the spun twisted yarn described in (e) and (i), which contains cotton fiber A and cotton fiber B having different average micronaire finenesses, and comprises the following steps (1) to (3): (1) A step of preparing a roving A containing 80% by mass or more of cotton fiber A having an average micronaire fineness of 4.0 to 6.0 (2) A step of preparing roving B containing 80% by mass or more of cotton fiber B having an average micronaire fineness of 3.0 to 5.0 and smaller than the average micronaire fineness of cotton fiber A. (3) A process in which roving A and roving B are supplied to the drafting area of ​​a ring spinning frame, drafted, and then twisted to a twist coefficient of 4.2 to 8.0. [Effects of the Invention]

[0010] The spun cross-twisted yarn of the present invention is a spun yarn made from cotton fibers that exhibits excellent stretchability and stretch-back properties after alkali treatment (mercerization). Furthermore, woven or knitted fabrics obtained using the spun cross-twisted yarn can be mercerized to impart stretchability and stretch-back properties to the woven or knitted fabrics. This invention focuses on the property of cotton fibers that shrink when mercerized, thereby developing stretchability (extensibility). While typical mercerization processes involve strong tension on yarns or woven or knitted fabrics to suppress cotton fiber shrinkage, this invention aims to impart stretchability to spun cotton fibers by processing with no or low tension. Furthermore, by using cotton fibers A and B with different average micronaire finenesses and spinning and twisting them to produce a spun cross-twisted yarn, it becomes possible to obtain a spun yarn that exhibits excellent stretchability and stretch-back properties (elongation recovery) when mercerized with no or low tension.

[0011] Therefore, by using the spun twisted yarn of the present invention, woven and knitted fabrics having excellent stretchability and stretch-back properties, and having a low number of fluffs and an excellent smooth texture can be obtained, and therefore can be suitably used in clothing applications such as socks, underwear, mid-layers, outerwear, etc. Furthermore, since there is no need to prepare single yarns such as hard twisted spun yarns, the fabrics can be obtained with good operability. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a schematic perspective view showing the main parts of an example of a ring spinning machine used in the manufacturing method of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0013] The present invention will be described in detail below.

[0014] The spun twisted yarn of the present invention is made of cotton fibers and has the form of a single yarn. The cotton fibers include two types of cotton fibers with different average Micronaire finenesses. Hereinafter, the one with the relatively larger average Micronaire fineness will be referred to as Cotton Fiber A, and the one with the smaller average Micronaire fineness will be referred to as Cotton Fiber B.

[0015] Here, cotton fibers have the property that they swell and shrink when subjected to alkali treatment, and it has been found that cotton fibers with a larger average micronaire fineness tend to shrink more. By making the average fineness of cotton fiber A greater than that of cotton fiber B in the spun cross-twisted yarn of the present invention, cotton fiber A shrinks more than cotton fiber B after alkali treatment, and cotton fiber A has greater stretchability. Meanwhile, cotton fiber B shrinks less than cotton fiber A after alkali treatment, and its stretchability is also less than cotton fiber A.

[0016] The average Micronaire fineness of cotton fiber A is preferably 4.0 to 6.0, more preferably 4.2 to 5.5, and even more preferably 4.2 to 4.8, while that of cotton fiber B is preferably 3.0 to 5.0, more preferably 3.1 to 4.5, and even more preferably 3.1 to 3.9.

[0017] In the present invention, it is important to use two types of cotton fibers with different average micronaire finenesses. By utilizing the difference in the degree of shrinkage (fiber swelling) between cotton fiber A and cotton fiber B when subjected to alkali treatment under no tension, a spun and twisted yarn with excellent stretchability and stretch-back properties can be obtained. Generally, cotton spun yarns are considered to have almost no stretch-back properties. For example, a spun yarn consisting only of cotton fiber A will shrink significantly after alkali treatment, and even if it exhibits stretchability, it will not recover (stretch-back) and will retain its elongated state. Therefore, in the present invention, cotton fiber A and cotton fiber B, which have different finenesses, are used in combination. The difference in shrinkage allows the entire yarn to form a coil spring-like crimped structure after alkali treatment, and the stretch caused by cotton fiber A is appropriately suppressed by cotton fiber B, thereby imparting stretch-back properties to the spun and twisted yarn. This allows for a well-balanced and excellent stretchability and stretch-back properties.

[0018] From the viewpoint of achieving excellent stretchability and stretch-back properties of the spun cross-twisted yarn, the difference in average Micronaire fineness between cotton fiber A and cotton fiber B is preferably 0.5 or more, more preferably 1.0 or more, and the upper limit of the difference in average fineness is preferably about 2.0. If the difference in average Micronaire fineness is 0.5 or more, the difference in shrinkage between cotton fiber A and cotton fiber B after alkali treatment will be sufficient, and the spun cross-twisted yarn can have excellent stretchability and stretch-back properties.

[0019] Examples of cotton fibers with an average Micronaire fineness of 4.0 to 6.0 include cotton from the United States, Peru, Australia, and China. Examples of cotton fibers with an average Micronaire fineness of 3.0 to 4.0 include cotton from India, the United States, China, and Egypt. Combinations of cotton fibers A and B are not limited, but a preferred example is a combination of Australian cotton with an average fineness of approximately 4.4 and Indian cotton with an average fineness of approximately 3.1. Furthermore, cotton fiber A preferably has an effective fiber length of 25.0 mm or more, more preferably 27.0 to 33.0 mm. Meanwhile, cotton fiber B preferably has an effective fiber length of 27.0 mm or more, more preferably 28.0 to 45.0 mm, and even more preferably 33.0 to 42.0 mm.

[0020] The average Micronaire fineness is measured based on JIS L1019 7.4.1 (Micronaire method), and the effective fiber length is measured based on JIS L1019 7.2.1 (Sorter method).

[0021] The spun cross-twisted yarn of the present invention has the form of a single yarn obtained by cross-twisting two rovings. It differs from a doubled-twisted yarn obtained by twisting together a single yarn of cotton fiber A, which is a spun yarn obtained through a spinning process, and a single yarn of cotton fiber B, which is a spun yarn obtained in the same manner, or a covered yarn obtained by preparing two or more of the above single yarns to form a core-sheath configuration. The spun cross-twisted yarn can be obtained by simultaneously inserting two fiber bundles (slivers or rovings) into a two-hole trumpet (with a spacing of 2 to 15 mm) of a spinning frame and passing them parallel between the back roller and the front roller. Furthermore, during the manufacturing process, the two rovings act to cover each other's fuzz, resulting in less fuzz on the yarn surface than a spun yarn made of a single ordinary roving. Therefore, the spun cross-twisted yarn of the present invention is a spun yarn with excellent stretchability and stretch-back properties, and also has the advantage of having less fuzz and a better texture than doubled-twisted yarns or covered yarns.

[0022] The spun cross-twisted yarn of the present invention contains cotton fiber A and cotton fiber B, and the fiber content is not limited as long as the spun cross-twisted yarn has a specific or higher elongation percentage and elongation recovery percentage after alkali treatment under no tension. That is, the spun cross-twisted yarn may be made of a roving obtained by mixing raw cotton fibers A and B, but it is preferable that the roving A made of cotton fiber A and the roving B made of cotton fiber B are spun cross-twisted and contained. In this embodiment of the present invention, the fiber bundles of fiber A and the fiber bundles of fiber B are contained in the spun cross-twisted yarn so that they are each appropriately cohesive, and as a result, the stretchability and stretch-back properties due to the synergistic effect of cotton fiber A and cotton fiber B are easily exhibited. Furthermore, when raw cotton fiber A and raw cotton fiber B are mixed and beaten in advance to prepare a roving, which is then spun and twisted to obtain a spun and twisted yarn, the spun and twisted yarn will not contain fiber A and fiber B in the form of properly gathered fiber bundles, but will instead contain both fibers uniformly dispersed, which may result in reduced stretchability and stretch-back properties. Therefore, it is necessary to select the types of cotton fibers A and B and adjust the manufacturing conditions, etc.

[0023] From the viewpoint of imparting a good balance between stretchability and stretch-back properties, the mass ratio of cotton fiber A to cotton fiber B contained in the spun twisted yarn of the present invention is preferably cotton fiber A / cotton fiber B=30 / 70 to 70 / 30, more preferably 40 / 60 to 60 / 40. Furthermore, the total content of cotton fiber A and cotton fiber B in the spun twisted yarn is preferably 80 mass% or more, more preferably 85 mass% or more, and particularly preferably 100 mass% (i.e., a spun twisted yarn consisting only of cotton fiber A and cotton fiber B).

[0024] The spun twisted yarn of the present invention has an elongation percentage of 12.0% or more, preferably 13.0% or more, and more preferably 14.5% or more, after immersion in an alkaline solution at 20°C for 2 minutes under no tension. Furthermore, the elongation recovery percentage of 61% or more, preferably 62% or more, and more preferably 63% or more, after immersion in an alkaline solution at 20°C for 2 minutes under no tension. If the elongation percentage is 12.0% or more and the elongation recovery percentage is 61% or more, it can be used as a spun yarn made of cotton fibers that has both stretchability and stretch-back properties and can be used for woven and knitted fabrics. In the present invention, the elongation percentage and elongation recovery percentage are values ​​measured by the following method, mutatis mutandis, in accordance with JIS L1013 8.11 Elasticity Method B. (Measurement method) First, a spun twisted yarn is cut into a 5-winding skein using a measuring machine with a frame circumference of 1.125 m. The skein is then immersed in a 25°Be' (Baume) sodium hydroxide solution (20°C) for 2 minutes without tension to obtain an alkali-treated skein yarn sample. Next, an initial load (0.176 mN x 10 x indicated tex (tex = 590.5 / converted to cotton count)) is applied to the skein yarn sample, and after 30 seconds, the skein length A is measured. The initial load is removed, and a heavy load (8.82 mN x 10 x indicated tex (tex = 590.5 / converted to cotton count)) is applied, and after 30 seconds, the skein length B is measured. Next, the heavy load is removed, and after 2 minutes, the initial load is applied again, and after 30 seconds, the skein length C is measured. The stretching elongation rate (elongation rate) and stretching elastic modulus (stretching recovery rate) are calculated using the following formulas. Stretching elongation rate (%) = (BA) / A x 100 Elastic modulus (%) = (BA) / (B-C) x 100

[0025] When cotton fibers are immersed in an alkaline solution, the longer the immersion time, the greater the fiber shrinkage. For example, at a treatment temperature of 20°C, it is known that the fibers shrink most after immersion for approximately 10 minutes. While fiber shrinkage leads to the formation of crimps and improved elongation, excessive shrinkage also tends to reduce elongation recovery. Furthermore, mercerization, a processing method for woven and knitted fabrics containing cotton fibers, typically involves immersion in an alkaline solution for approximately 1 to 2 minutes. In consideration of the above, the spun cross-twisted yarn of the present invention has an elongation of 12.0% or more and an elongation recovery of 61% or more after immersion in an alkaline solution at 20°C for 2 minutes under no tension. This allows the resulting woven and knitted fabrics to have excellent stretchability and stretch-back properties after mercerization. Methods for achieving the elongation and elongation recovery within the above ranges include selecting the type of cotton fiber constituting the cross-twisted yarn, or adjusting the twist coefficient K of the cross-twisted yarn or the alkali shrinkage rate (described below).

[0026] In order to impart stretchability and stretch-back properties to the spun twisted yarn of the present invention, it is preferable to carry out the alkali treatment without tension, from the viewpoint of increasing the swelling and shrinkage of the cotton fibers A and B.

[0027] The spun twisted yarn of the present invention preferably has a shrinkage rate (alkali shrinkage rate) of 13 to 24%, more preferably 13 to 20%, after immersion in an alkaline solution at 20°C for 2 minutes under no tension. The cotton fibers constituting the spun twisted yarn of the present invention have the property of swelling and shrinking when subjected to alkaline treatment. In the present invention, this property is utilized to impart an appropriate elongation rate and elongation recovery rate to the spun twisted yarn. An alkali shrinkage rate of 13 to 24% ensures that the spun twisted yarn has an elongation rate and elongation recovery rate within the above-mentioned specific range. Methods for adjusting the alkali shrinkage rate within the above-mentioned range include selecting the type of cotton fiber constituting the spun twisted yarn and adjusting the twist coefficient K of the spun twisted yarn.

[0028] The spun twisted yarn may contain fibers other than cotton fiber A and cotton fiber B as long as the above-mentioned effects are not impaired. Examples of other fibers include cotton fibers other than fibers A and B, other natural fibers, synthetic fibers, semi-synthetic fibers, and regenerated fibers, and a combination of these may be included. Natural fibers other than cotton can be either plant or animal fibers. Plant fibers include hemp and kapok fibers. Animal fibers include wool and silk. Synthetic fibers include polyester, polyamide (nylon), acrylic, polyolefin, para-aramid, meta-aramid, and polyarylate. Semi-synthetic fibers include cellulose-based semi-synthetic fibers such as diacetate and triacetate. Regenerated fibers include cellulose-based regenerated fibers such as viscose rayon and Tencel (modal, lyocell). The method for incorporating other fibers is not limited, but for example, they may be included as part of the roving A or roving B, or they may be incorporated as a roving other than rovings A and B by being subjected to spinning and twisting together with rovings A and B.

[0029] The twist coefficient K of the spun cross-twisted yarn of the present invention is preferably 4.2 to 8.0, more preferably 5.0 to 7.0, and even more preferably 5.3 to 6.5. If the twist coefficient K is less than 4.2, the twist of the yarn as a whole is low, resulting in small crimps of cotton fiber A and cotton fiber B due to shrinkage after alkali treatment, resulting in poor stretchability and stretch-back properties. On the other hand, if the twist coefficient K exceeds 8.0, the twist of the yarn as a whole is too strong, causing excessive restraint between the fibers, resulting in small shrinkage after alkali treatment and poor stretchability, which is undesirable. As will be described later, in the method for producing the spun cross-twisted yarn of the present invention, two or more rovings are supplied to a spinning frame and cross-twisted. Therefore, the twist structure of the resulting spun cross-twisted yarn is the same overall, and the twist coefficient K of all fibers contained therein is substantially the same. For example, the twist coefficient K and twist angle of the fibers in the inner and outer layers of the yarn do not differ significantly.

[0030] The twist factor K can be calculated as follows. Twist factor (K) = number of twists (twists / 2.54cm) / √(British cotton count)

[0031] The thickness of the spun twisted yarn of the present invention is not limited, but is preferably 10 to 120 count in British cotton count, and more preferably 20 to 60 count. Generally, spun twisted yarns are indicated as "(British cotton count x 2) / 2" or "(British cotton count x 2) / T." For example, a spun twisted yarn with a spun yarn count of 120 is written as "spun twisted 240 / 2" or "240 / T."

[0032] Because the spun twisted yarn of the present invention is a spun yarn obtained by spun twisting, it can be made to have less fuzz than single yarns, doubled yarns, or covered yarns. Therefore, when made into woven or knitted fabrics, it has an excellent soft cotton feel, and as a secondary effect, it also has good anti-pilling properties. The number of fuzz particles is not limited, but for example, it is preferable that the number of fuzz particles of 3 mm or more is 200 particles / 10 m or less, and that the number of fuzz particles of 5 mm or more is 40 particles / 10 m or less.

[0033] The spun cross-twisted yarn of the present invention can also be made into a plied yarn by plying multiple strands of the yarn together. The plied yarn may be any of two-ply yarn, three-ply yarn, four-ply yarn, etc. Furthermore, it may be plied with other yarns as needed. From the viewpoint of reducing torque, the twist direction of the plied yarn is preferably opposite to that of the first twist (twist of the spun yarn). Yarns with high torque tend to cause the structure of woven or knitted fabrics to be oblique. When making a plied yarn, it is preferable to adjust the number of twists in the plied twist so as not to excessively impair the elongation and elongation recovery of the spun cross-twisted yarn of the present invention.

[0034] Next, the method for producing the spun twisted yarn of the present invention will be described. The method for producing the spun twisted yarn of the present invention is not limited to a method in which the elongation rate and elongation recovery rate after alkali treatment under no tension are at least specific levels, but a method for producing the spun twisted yarn containing cotton fiber A and cotton fiber B having different average micronaire finenesses and including the following steps (1) to (3) can be suitably adopted. (1) A step of preparing a roving A containing 80% by mass or more of cotton fiber A having an average micronaire fineness of 4.0 to 6.0 (2) A step of preparing roving B containing 80% by mass or more of cotton fiber B having an average micronaire fineness of 3.0 to 5.0 and smaller than the average micronaire fineness of cotton fiber A. (3) A process in which roving A and roving B are supplied to the drafting area of ​​a ring spinning frame, drafted, and then twisted to a twist coefficient of 4.2 to 8.0. Hereinafter, one embodiment of the method for obtaining spun twisted yarn of the present invention will be described with reference to the drawings.

[0035] In steps (1) and (2), roving A made of cotton fiber A and roving B made of cotton fiber B that will constitute the spun twisted yarn are prepared. Specifically, roving A preferably contains 80% by mass or more, more preferably 85% by mass or more, and particularly preferably 100% by mass (i.e., a roving made only of cotton fiber A) of cotton fiber A having an average Micronaire fineness of 4.0 to 6.0. Roving B contains cotton fiber B having an average Micronaire fineness of 3.0 to 5.0 that is smaller than that of cotton fiber A, and preferably contains 80% by mass or more, more preferably 85% by mass or more, and particularly preferably 100% by mass (i.e., a roving made only of cotton fiber B).

[0036] In the step (3), the two rovings A and B prepared in steps (1) and (2) are fed into a ring spinning frame for spinning. The spinning step can be carried out using a known or commercially available spinning frame, and one embodiment will be described with reference to FIG.

[0037] The rovings A and B fed to the spinning frame are fed in parallel to a draft area consisting of a back roller 13, an apron 14, and a front roller 15 via a guide bar 11 and a regulating guide 12, where they are drafted at a predetermined draft ratio. Next, the rovings A and B spun from the draft area are joined together and sent to a ring 17 via a snail guide 16, where they are twisted by a ring traveler 17a that rotates along the ring 17, and wound around a bobbin 18 as a spun twisted yarn Y.

[0038] When twisting in the spinning process, the twist coefficient K is preferably 4.2 to 8.0, more preferably 5.0 to 7.0, and even more preferably 5.3 to 6.5.

[0039] Furthermore, a compact spinning system can be introduced during ring spinning to further reduce the number of fuzz fibers by increasing the density of the fiber bundles during the spinning process. The compact spinning system is a means for suppressing fuzz by improving the uniformity of the fiber bundles and improving fiber convergence, which is achieved by an air suction type focusing mechanism, and the air suction type focusing mechanism is usually installed between the drafting zone and the twisting zone. By introducing a compact spinning system, the spun yarn becomes dense with less fuzz, and as a result, improvements in strength and elongation can be expected. Air suction type focusing mechanisms include a perforated apron system and a perforated drum system, and either system can be used in the present invention.

[0040] The woven or knitted fabric of the present invention contains the spun twisted yarn of the present invention. In order to impart stretchability and stretch-back properties to the woven or knitted fabric, it is necessary to subject the spun twisted yarn to an alkali treatment (mercerization). Mercerization may be applied to the supplied yarn before weaving and knitting, or to the entire woven or knitted fabric after weaving and knitting. From the viewpoint of ease of processing, however, it is more preferable to apply mercerization to the woven or knitted fabric after weaving and knitting.

[0041] In the present invention, from the viewpoint of imparting stretchability and stretch-back properties to woven and knitted fabrics, it is preferable that mercerization be performed with no or low tension in at least one of the warp and weft directions of the woven and knitted fabric. Conventional mercerization is performed with strong tension applied to the woven and knitted fabric in both the warp and weft directions to suppress shrinkage due to swelling of the cotton fibers, with the aim of improving texture, luster, and dyeability. However, when mercerizing a woven or knitted fabric containing the spun twisted yarn of the present invention, it is necessary to shrink the cotton fibers A and B in the spun twisted yarn by alkali treatment in order to impart stretchability and stretch-back properties. Therefore, it is preferable that the woven and knitted fabric be processed with low or no tension, without strong tension, at least in the direction in which stretchability is desired, so that the desired elongation and stretch recovery are achieved.

[0042] For example, when using a clip-type mercerizing machine or a chainless mercerizing machine used in conventional mercerization (mercerization), a woven or knitted fabric having the spun twisted yarn of the present invention arranged at least in the weft direction is prepared. The woven or knitted fabric is then immersed in an alkaline aqueous solution bath, squeezed with a mangle, and passed between rollers while applying tension in the warp direction. The woven or knitted fabric is then passed through rollers with no or low tension in the weft direction while adjusting its width, thereby shrinking the spun twisted yarn in the woven or knitted fabric and imparting stretchability and stretch-back properties to the woven or knitted fabric. Note that when using the above-mentioned device, tension in the warp direction can cause the woven or knitted fabric to arch or become uneven in width in the weft direction. Therefore, it is preferable to apply low tension in the weft direction to a level that achieves the desired elongation and stretch recovery rate in order to achieve a uniform width. The formulation of the processing agent and processing conditions during mercerization, as well as the crosslinking treatment after mercerization, may be any known method.

[0043] The content of the spun twisted yarn of the present invention in the woven or knitted fabric is preferably 30% by mass or more, more preferably 50% by mass or more, even more preferably 70% by mass or more, and may be 100% by mass (i.e., a woven or knitted fabric using only the spun twisted yarn of the present invention). In particular, the spun twisted yarn of the present invention may be arranged in the direction in which it is desired to impart stretchability and stretch-back properties to the woven or knitted fabric, and it is preferable that the content be 50% by mass or more in that direction.

[0044] The woven and knitted fabrics are not particularly limited in terms of weave. Examples of woven fabrics include plain weave, twill weave, satin weave, pile weave, and variations thereof. Knitted fabrics may be either warp knitted or weft knitted. Examples of warp knitted fabrics include denbigh knit, cord knit, and atlas knit, and specific examples include tricot half and tricot satin. Examples of weft knitted fabrics include plain knit, rib knit, purl knit, and smooth knit, and specific examples include jersey, pique, and smooth. The elongation percentage and elongation recovery percentage of woven or knitted fabrics are not particularly limited and will vary depending on the content of the spun twisted yarn of the present invention in the woven or knitted fabric, but for example, in the case of woven fabrics, the elongation percentage is preferably 10% or more, more preferably 15% or more, to have stretchability. Also, in the case of stretch-back fabrics, the elongation recovery percentage is preferably 80% or more, more preferably 82% or more.

[0045] The spun twisted yarn of the present invention has a specific or higher elongation rate and elongation recovery rate after alkali treatment under no tension, and therefore can exhibit stretchability and stretch-back properties even when used in woven or knitted fabrics.

[0046] The woven or knitted fabric of the present invention can be used mainly for clothing applications, and is particularly suitable for use in socks, underwear, innerwear, outerwear, etc. [Example]

[0047] The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.

[0048] 1. Various characteristic values ​​and evaluations (a) Number The obtained spun twisted yarn was used and measured in accordance with JIS L-1095 9.4.1. (b) Number of twists The obtained spun twisted yarn was used and measured in accordance with JIS L-1095 9.15.1, Method B.

[0049] (c) Elongation and elongation recovery of spun twisted yarn after alkali treatment The obtained spun twisted yarn was measured by the above-mentioned method. (d) Alkali shrinkage rate (shrinkage rate after alkali treatment) The resulting spun twisted yarn was used to measure the shrinkage upon alkali treatment according to JIS L1013 8.18.1, Hot Water Dimensional Change (Method A). Specifically, the resulting spun twisted yarn was first cut into a 5-winding skein using a measuring machine with a frame circumference of 1.125 m, and the skein length A was measured under a load 10 times the cotton count load (see the initial load listed in JIS L1095 6.1 Table 2). Next, after removing the load, the skein was immersed in a 25°Be' (Baume) sodium hydroxide solution (20°C) for 2 minutes under no tension to perform an alkali treatment. After the alkali treatment, the skein was removed and dried horizontally in a dryer at 40°C. The skein length B was again measured under a load 10 times the cotton count load. The shrinkage was calculated using the following formula: Alkali shrinkage rate (%) = (BA) ÷ A × 100

[0050] (e) Fabric elongation The resulting woven fabric was used as a sample, and the elongation in the weft direction (the direction in which the spun twisted yarn of the present invention was arranged) was measured by the method specified in JIS L 1096 A (constant rate elongation method) under a load of 14.7 N and a gauge length of 200 mm. (f) Elongation recovery rate of fabric The obtained woven fabric was used as a sample, and the elongation recovery in the weft direction (the direction in which the spun twisted yarn of the present invention was arranged) was measured by the method specified in JIS L 1096 Method A (constant rate elongation method) under the same conditions as in (e) above, where the load was removed and the initial load was applied one hour later, and the recovery was determined from the length between the benchmark lines. (g) Fluff count evaluation The number of 3mm (3mm or more) and 5mm (5mm or more) fluffs (pieces / 10m) of the obtained spun twisted yarn was measured according to the "Fluff" 9.22.2B method in JIS-L-1095 General Spun Yarn Testing Method.

[0051] 2. Short fibers used The physical properties, sources, etc. of the short fibers used in the examples and comparative examples are as follows: Cotton fiber 1: Australian cotton with a micronaire fineness of 4.4 μg / inch and an effective fiber length of 28.6 mm Cotton fiber 2: Indian cotton with a micronaire fineness of 3.1 μg / inch and an effective fiber length of 36.5 mm Cotton fiber 3: Giza cotton with a micronaire fineness of 4.1 μg / inch and an effective fiber length of 33.4 mm Cotton fiber 4: Supima Gold cotton with a micronaire fineness of 3.1 μg / inch and an effective fiber length of 38.9 mm

[0052] Example 1 Cotton fiber 1 and cotton fiber 2 were separately fed into a cotton mixing machine to form a mixed cotton wrap, and then the mixed cotton wrap was introduced into a carding machine to obtain carded sliver 1 composed of cotton fiber 1 and carded sliver 2 composed of cotton fiber 2. Next, carded slivers 1 and 2 were each doubled to form a wrapped sheet, which was then combed to obtain combed sliver 1 and combed sliver 2. The obtained combed slivers 1 and 2 were drawn to obtain drawn slivers 1 and 2 of 400 gr / 6 yd, and drawn slivers 1 and 2 were roving spun to obtain rovings 1 and 2 of 240 gr / 30 yd. Then, roving 1 and roving 2 were simultaneously introduced into the spinning frame at a mass ratio (cotton fiber A / B) of 50 / 50, and after drafting at approximately 40 times, a twist of 24.6 times / 2.54 cm was given to obtain a spun twisted yarn with a total count of 20 (40 / T). The twist coefficient of this spun twisted yarn was measured and found to be 5.5.

[0053] Next, an air-jet loom was used to weave a plain weave fabric with a greige density (warp x weft) of 58 threads / 2.54 cm x 56 threads / 2.54 cm, using a blended warp yarn containing 65% polyester and 35% cotton by weight and the above-mentioned spun cross-twisted yarn as the weft. The greige fabric was then scoured and bleached, and then mercerized using a mercerizing machine (SANDO TECH, Model OSS-MT) under conditions of an alkali concentration of 25°Be' (Baume), a temperature of 20°C, and a time of 2 minutes. During processing, the warp direction of the fabric passed through the machine under the same tension as in a conventional mercerizing process, while the weft direction, containing the spun cross-twisted yarn, passed through the machine under a lower tension to adjust the width by approximately +2 to 5 cm relative to the fabric passing under the same tension. This resulted in a woven fabric.

[0054] Example 2 Cotton fiber 1 and cotton fiber 2 were fed into the same cotton blowing machine at a mass ratio (cotton fiber A / B) of 50 / 50 to form a mixed cotton lap. The mixed cotton lap was then introduced into a carding machine to obtain carded sliver 5 composed of cotton fiber 1 and cotton fiber 2. Next, carded sliver 5 was doubled to form a wrapped sheet, which was then combed to obtain combed sliver 5. The resulting combed sliver 5 was drawn into a drawn sliver 5 of 400 gr / 6 yd. The drawn sliver 5 was then roved to obtain a roving 5 of 240 gr / 30 yd. Two rovings 5 ​​were prepared and introduced simultaneously into a spinning frame. After being drafted at approximately 40 times, they were twisted 24.6 times / 2.54 cm to obtain a spun twisted yarn with a total count of 20 (40 / T). The twist coefficient of this spun twisted yarn was measured and found to be 5.5. The resulting spun twisted yarn was then woven, scoured and bleached in the same manner as in Example 1, and then mercerized to obtain a woven fabric.

[0055] Example 3 A spun twisted yarn having a total count of 20 (40 / T) was obtained in the same manner as in Example 1, except that roving 1 and roving 2 were introduced into the spinning frame and twisted at 18.8 turns / 2.54 cm. The twist coefficient of this spun twisted yarn was measured and found to be 4.2. The resulting spun twisted yarn was then woven, scoured and bleached in the same manner as in Example 1, and then mercerized to obtain a woven fabric.

[0056] Example 4 A spun twisted yarn having a total count of 20 (40 / T) was obtained in the same manner as in Example 1, except that roving 1 and roving 2 were introduced into the spinning frame and twisted at 35.8 turns / 2.54 cm. The twist coefficient of this spun twisted yarn was measured and found to be 8.0. The resulting spun twisted yarn was then woven, scoured and bleached in the same manner as in Example 1, and then mercerized to obtain a woven fabric.

[0057] Example 5 A spun twisted yarn having a total count of 20 (40 / T) was obtained in the same manner as in Example 1, except that a compact spinning frame (RX300, manufactured by Toyota Industries Corporation) was used as the spinning frame. The twist coefficient of this spun twisted yarn was measured and found to be 5.5. The resulting spun twisted yarn was then woven, scoured and bleached in the same manner as in Example 1, and then mercerized to obtain a woven fabric.

[0058] Example 6 Cotton fiber 3 and cotton fiber 4 were separately fed into a cotton mixing machine to form a mixed cotton wrap, and then the mixed cotton wrap was introduced into a carding machine to obtain carded sliver 3 composed of cotton fiber 3 and carded sliver 4 composed of cotton fiber 4. Next, carded slivers 3 and 4 were each doubled to form a wrapped sheet, which was then combed to obtain combed sliver 3 and combed sliver 4. The obtained combed slivers 3 and 4 were drawn to obtain drawn slivers 3 and 4 of 300 gr / 6 yd, and drawn slivers 3 and 4 were roving spun to obtain rovings 3 and 4 of 180 gr / 30 yd. Then, roving 3 and roving 4 were simultaneously introduced into the spinning frame at a mass ratio (cotton fiber A / B) of 50 / 50, and after drafting at approximately 40 times, a twist of 30.1 times / 2.54 cm was given to obtain a spun twisted yarn with a total count of 30 (60 / T). The twist coefficient of this spun twisted yarn was measured and found to be 5.5. The resulting spun twisted yarn was then woven, scoured and bleached in the same manner as in Example 1, and then mercerized to obtain a woven fabric.

[0059] (Comparative Example 1) Combed sliver 1 was obtained using only cotton fiber 1 in the same manner as in Example 1, and the resulting combed sliver 1 was then drawn to form a 440 gr / 6 yd drawn sliver 1'. The drawn sliver 1' was then roving spun to obtain a 360 gr / 30 yd roving 1'. Two rovings 1' were prepared and simultaneously introduced into a spinning frame. After being drafted at approximately 31.0 times, they were twisted 17 times / 2.54 cm to obtain a spun twisted yarn with a total count of 20 (40 / T). The twist coefficient of this spun twisted yarn was measured and found to be 3.8. The resulting spun twisted yarn was then woven, scoured and bleached in the same manner as in Example 1, and then mercerized to obtain a woven fabric.

[0060] (Comparative Example 2) A roving 1' was obtained using only cotton fiber 1 in the same manner as in Comparative Example 1, and then two rovings 1' were simultaneously introduced into a spinning frame, and a twist of 24.6 turns / 2.54 cm was imparted to the roving 1' after drafting, and a spun twisted yarn having a total count of 20 (40 / T) was obtained in the same manner as in Comparative Example 1. The twist coefficient of this spun twisted yarn was measured and found to be 5.5. The resulting spun twisted yarn was then woven, scoured and bleached in the same manner as in Example 1, and then mercerized to obtain a woven fabric.

[0061] (Comparative Example 3) Cotton fiber 2 and cotton fiber 4 were separately fed into a cotton mixing machine to form a mixed cotton wrap, and then the mixed cotton wrap was introduced into a carding machine to obtain carded sliver 2 composed of cotton fiber 2 and carded sliver 4 composed of cotton fiber 4. Next, carded slivers 2 and 4 were each doubled to form a wrapped sheet, which was then combed to obtain combed sliver 2 and combed sliver 4. The obtained combed slivers 2 and 4 were drawn to obtain drawn slivers 2 and 4 of 400 gr / 6 yd, and drawn slivers 2 and 4 were roving spun to obtain rovings 2 and 4 of 240 gr / 30 yd. Then, roving 2 and roving 4 were simultaneously introduced into the spinning frame at a mass ratio (cotton fiber A / B) of 50 / 50, and after drafting at approximately 40 times, a twist of 24.6 times / 2.54 cm was given to obtain a spun twisted yarn with a total count of 20 (40 / T). The twist coefficient of this spun twisted yarn was measured and found to be 5.5. The resulting spun twisted yarn was then woven, scoured and bleached in the same manner as in Example 1, and then mercerized to obtain a woven fabric.

[0062] Comparative Example 4 Roving 1 obtained in the same manner as in Example 1 using only fiber 1 was introduced into a roving frame, and after about 40 times drafting, was given a twist of 26.5 times / 2.54 cm to produce a single yarn of 40 count. The twist coefficient of this single yarn was measured and found to be 4.2. Next, two of these single yarns were doubled, and then introduced into a twisting machine and given a second twist (S twist) of 30.6 times / 2.54 cm to produce a two-ply yarn of 40 count. Next, the obtained two-fold yarn was woven, scoured, bleached, and then mercerized in the same manner as in Example 1 to obtain a woven fabric.

[0063] (Comparative Example 5) Cotton fiber 1 and cotton fiber 3 were fed into the same cotton blending machine at a mass ratio (cotton fiber A / B) of 50 / 50 to form a mixed cotton wrap. The mixed cotton wrap was then introduced into a carding machine to obtain carded sliver 6 composed of cotton fiber 1 and cotton fiber 3. Next, carded sliver 6 was doubled to form a wrapped sheet, which was then combed to obtain combed sliver 6. The resulting combed sliver 6 was drawn into a drawn sliver 6 of 400 gr / 6 yd. The drawn sliver 6 was then roved to obtain a roving 6 of 240 gr / 30 yd. Two rovings 6 were prepared and introduced simultaneously into a roving frame. After being drafted at approximately 40 times, they were twisted 17 times / 2.54 cm to obtain a single spun yarn with a cotton count of 20. The twist coefficient of this spun yarn was measured and found to be 3.8. The resulting spun yarn was then woven, scoured and bleached in the same manner as in Example 1, and then mercerized to obtain a woven fabric.

[0064] The results of the spun yarns and woven fabrics obtained in Examples 1 to 6 and Comparative Examples 1 to 5 are shown in Table 1.

[0065] [Table 1]

[0066] As is clear from Table 1, the spun twisted yarns obtained in Examples 1 to 4 were excellent in both elongation and elongation recovery after alkali treatment, and the woven fabrics obtained by weaving the spun twisted yarns and then alkali treating them had sufficient stretch and stretch-back properties. On the other hand, the spun twisted yarn obtained in Comparative Example 1 was made using only one type of cotton fiber, had a small twist coefficient K, and did not have a coil spring-like crimped structure formed throughout the yarn as in the spun twisted yarn of the present invention, so had a poor elongation recovery rate after alkali treatment. The spun twisted yarn obtained in Comparative Example 2 was made using only one type of cotton fiber, and although it had a large twist coefficient K, it did not have a coil spring-like crimped structure formed throughout the yarn, as in the spun twisted yarn of the present invention. Therefore, although it had an excellent elongation rate after alkali treatment, it had a poor elongation recovery rate. The spun twisted yarn obtained in Comparative Example 3 had insufficient elongation and elongation recovery after alkali treatment because the difference in average micronaire fineness between the two types of cotton fibers was not large. The two-ply yarn obtained in Comparative Example 4 had an excellent elongation rate after alkali treatment because it used cotton fibers with a large Micronaire fineness, but because it was made by plying and twisting two single yarns and did not have a coil spring-like crimped structure formed throughout the yarn as in the spun and twisted yarn of the present invention, it had a poor elongation recovery rate after alkali treatment.In addition, it was necessary to prepare a hard twist yarn in the manufacturing process, which resulted in poor operability. The spun yarn obtained in Comparative Example 5 had insufficient elongation and elongation recovery after alkali treatment because the difference in average micronaire fineness between the two types of cotton fibers was not large. In addition, since it was a single-filament spun yarn, a lot of fluff was generated and the feel was poor. [Explanation of symbols]

[0067] 11 Guide bar 12 Regulatory Guide 13 Back roller 14 Apron 15 Front roller 16 Snail Guide 17 Ring 17a Ring Traveler 18 bobbins Y spun cross-twisted yarn

Claims

1. A spun twisted yarn made of cotton fibers, the spun yarn being a single yarn, having an elongation percentage of 12% or more after immersion in an alkaline solution at 20°C for 2 minutes under no tension, and an elongation recovery percentage of 61% or more after immersion in an alkaline solution at 20°C for 2 minutes under no tension.

2. 2. The spun cross-twisted yarn according to claim 1, which is a spun yarn comprising cotton fiber A and cotton fiber B having different average finenesses in Micronaire fineness, wherein a roving made of cotton fiber A and a roving made of cotton fiber B are cross-twisted by spun cross-twisting, and the twist coefficient K is 4.2 to 8.

0.

3. 3. The spun cross-twisted yarn according to claim 2, wherein the difference in average micronaire fineness between cotton fiber A and cotton fiber B is 0.5 or more.

4. A woven or knitted fabric comprising the spun cross-twisted yarn of claim 1.

5. A method for producing the spun twisted yarn according to claim 1, comprising cotton fiber A and cotton fiber B having different average finenesses in micronaire fineness, and comprising the following steps (1) to (3): (1) A step of preparing a roving A containing 80% by mass or more of cotton fiber A having an average micronaire fineness of 4.0 to 6.

0. (2) A step of preparing a roving B containing 80% by mass or more of cotton fiber B having an average Micronaire fineness of 3.0 to 5.0 and smaller than the average Micronaire fineness of cotton fiber A. (3) A step of supplying roving A and roving B to the drafting area of ​​a ring spinning frame, drafting them, and then twisting them so that the twist coefficient is 4.2 to 8.0.

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