JP2008174848A - Core yarn sewing thread and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a core yarn sewing thread having an excellent strength, sewability, improved appearance of stitches and excellent qualities. <P>SOLUTION: In the core yarn sewing thread obtained by primarily twisting a substantially twistless core yarn composite yarn in which a short fiber bundle being a sheath yarn along the length direction is wound at a total weight ratio of 30-60% on the circumference of a filament yarn being a core yarn, collecting several composite yarns, secondarily twisting the collected composite yarns in a direction opposite to the primary twist direction, the core yarn sewing thread has an average tensile break strength of ≥4.0 cN/dtex, a bending rigidity of ≤0.005 gfcm<SP>2</SP>/piece and a bending recovery of ≤0.006 gfcm/piece. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a core yarn sewing thread excellent in sewability and seam cleanliness for industrial sewing and home sewing, and a method for producing the same.

  In recent years, as the sewing technology has been improved by increasing the speed and automation of the sewing machine, there has been a demand for a thinner or higher-strength thread while maintaining a conventional level of sewability. Conventionally, as a synthetic fiber sewing thread, one using 100% filament yarn, one using 100% staple fiber, and a core yarn sewing thread using filament yarn as a core thread and staple staple fiber as a sheath are known. ing.

  The core yarn sewing thread is composed of a core yarn fiber made of a filament yarn and a sheath yarn fiber made of a drafted short fiber bundle, which are aligned in a core / sheath shape and supplied to a front roller of a spinning machine, None, and then, a plurality of the composite spun yarns are aligned and subjected to an upper twist in a direction opposite to the twist direction of the composite spun yarns. This core yarn sewing thread is higher in strength than a spinning thread only, so it is used for sewing jeans that require durability, thin fabrics or suits that require a beautiful finish. Yes.

  On the other hand, since the fluff of the short fibers constituting the sheath yarn of the core yarn sewing thread is more conspicuous than the filament sewing thread having a filament yarn composition ratio of 100%, the quality of the seam when sewing a thin fabric using the filament yarn It was difficult to develop high-end clothing.

  As a technique for improving the fundamental problems of these core yarn sewing yarns, for example, filament yarn that has already undergone a lower twist and normal span yarn are aligned and twisted and twisted with a twister. A “polyester mixed twist sewing thread” composed of a composite yarn having a twisted structure has been proposed (see, for example, Patent Document 1).

  Although this sewing thread is a reasonably manufactured mixed twist sewing thread, the filament yarn is not completely covered with the span yarn due to the twisted structure, so that the sewing property is low, and the filament yarn and the short fiber yarn As a result, the quality of the core yarn sewing thread was low.

  In addition, the filament yarn of the core yarn that has been electrospread by static electricity is evenly distributed within the cross section of the short fiber group that becomes the sheath yarn, and a core yarn is manufactured by composite spinning, and a plurality of the core yarns are aligned. A “composite sewing thread” having a high strength and a high elongation at break with an upper twist has been proposed (see, for example, Patent Document 2).

  This composite sewing thread is excellent in terms of sewing properties and uniform dyeability between the core / sheath, but by passing through the electric opening process, the manufacturing cost increases and fluff is likely to occur during the process. Therefore, there is a problem in that the quality is low and the elongation tends to be high, so that the buckling of the seam is likely to occur.

  Furthermore, other core yarn manufacturing apparatuses and manufacturing methods thereof have been proposed (see, for example, Patent Document 3), and further, a two-layer structured yarn and a manufacturing method thereof have been proposed (see, for example, Patent Document 4).

  These devices and methods include a hollow guide shaft body in which a yarn passage is formed in the nozzle axis direction, and a spinning section including a spinning section including a swirling flow generating nozzle that causes a swirling flow to act on the tip portion thereof, and a drafted short fiber This is a core yarn technique in which a bundle is wound around a filament supplied to a spinning unit.

  However, none of the conventional techniques are mentioned as an application technique of core yarn spinning, and no mention is made about the development of sewing threads. In addition, high-strength, high-definition properties are satisfied, and the sewing thread is excellent in sewing and quality. No technology has been proposed.

  Further, as a measure for reducing the generation of fluff, a method of fluffing through an air nozzle after a draft portion in the spinning process has been proposed (see, for example, Patent Document 5). Although the method of pulling out is completely different, the fluff itself is surely turned down, but basically it becomes a spun yarn that does not have a real twist to give the yarn strength by binding the fibers, and has a real twist similar to a ring spinning machine Is completely different in structure, and has a drawback that the texture becomes stiffer than the ring yarn.

  Furthermore, a “covering sewing thread” (for example, see Patent Document 6) based on a bundling spinning method has been proposed, but the winding amount of the sheath yarn is extremely small compared to the total yarn amount and is intermittent in the yarn length direction. In addition, since the winding direction is bundled, there is a fatal defect that the core portion is exposed in some places because the winding is not uniform. For this reason, the finished sewing thread lacks softness and has the disadvantage that it cannot handle complicated seams such as zigzag.

  That is, none of the conventional techniques has been proposed as a manufacturing thread as a sewing thread which satisfies fineness and high strength characteristics and is excellent in quality such as sewability and softness.

As described above, as for the core yarn sewing thread having the performance excellent in the sewing property and the thread appearance, it is a fact that a sufficient one has not been obtained yet.
JP-A-2-33341 Japanese Patent Publication No. 63-3777 JP 2002-69760 A JP 2002-69774 A JP-A-8-158167 JP-A-2-160943

  An object of the present invention is to solve the problems of the prior art, and can provide a core yarn sewing thread that is excellent in strength and softness of the thread. Further, the present invention is an industrial sewing machine or home automatic sewing machine. It is an object of the present invention to provide a core yarn sewing thread which is excellent in sewnability and excellent in the appearance of a sewing thread and a method for producing the same.

  In order to solve the above problems, the present invention has the following configuration.

(1) After applying a sub-twist to a substantially untwisted core-yarn composite fiber in which a short fiber serving as a sheath yarn is wound at a total weight ratio of 30% to 60% around a filament yarn serving as a core yarn, A core yarn sewing thread in which a plurality of yarns are twisted in the direction opposite to the direction of the lower twist, the average tensile breaking strength is 4.0 cN / dtex or more, the bending hardness is 0.005 gfcm ² / string, and the bending recovery A core yarn sewing thread characterized by having a property of 0.006 gfcm / piece or less.

  (2) The filament yarn has an average tensile breaking strength of 6.5 to 8.0 cN / dtex, a 10% modulus of 5.5 cN / dtex to 7.0 cN / dtex, and a dry heat shrinkage rate at 150 ° C. of 5 The core yarn sewing thread according to (1) above, which is ˜8%.

  (3) The short fiber bundle has an average tensile strength at break of 6.0 to 8.0 cN / dtex, a single fiber fineness of 0.5 to 1.2 dtex, and a dry heat shrinkage at 180 ° C. of 2.0 to 6 The core yarn sewing thread according to (1) or (2) above, characterized in that it is 5%.

  (4) In the spinning process, the short fibers drafted by the swirling airflow are entangled around the filament yarns, and then subjected to a lower twist in the same twisting direction as the winding direction to obtain a core yarn composite fiber, and the core yarn The method for producing a core yarn sewing thread according to any one of (1) to (3), wherein a plurality of composite fibers are aligned and subjected to an upper twist.

  According to the present invention, a short fiber that becomes a sheath yarn can have a reduced fluff, and has a beautiful yarn surface that cannot be obtained by the prior art, and provides a fine count, high strength, soft core yarn sewing thread. Can do.

  In addition, it has been considered impossible to apply real twist while fuzzing with conventional spun yarn. However, yarn can be spun by using the technology of the present invention, and high-speed sewing and household use are possible. A high-performance core yarn sewing thread that has excellent machineability and can be reduced in the sewing process can be obtained. Furthermore, it has the effect that the surface of the seam after sewing looks beautiful and the quality becomes excellent.

  The present invention has solved the above-mentioned problems, and as a result of intensive studies on a high-performance core yarn sewing thread in which thread skipping and thread breakage are less during sewing and the sewing conditions of the sewing machine can be easily adjusted, a substantially untwisted core yarn fiber is obtained. In addition, it was found that the problem can be solved all at once by applying a lower twist, and further arranging a plurality of yarns and applying an upper twist to make a sewing thread.

  The best mode of the core yarn sewing thread of the present invention will be described below.

First, as described above, the core yarn sewing thread of the present invention is wound around 30% to 60% of the total weight of the short fiber bundle serving as the sheath thread along the longitudinal direction around the filament yarn serving as the core thread. A core yarn sewing thread obtained by further twisting a plurality of substantially untwisted core yarn composite fibers wound and wound in the above. In this core yarn sewing thread, the average tensile breaking strength is 4.0 cN / dtex or more using a method of processing a swirling air flow described later, and the bending hardness measured by the KES bending property measurement method is 0.005 gfcm ^{2 for} the softness of the thread. It is possible to realize that the bending recovery property is 0.006 gfcm / piece or less.

  First, the core yarn composite fiber in the present invention will be described.

  The filament yarn used in the core yarn composite fiber in the present invention can of course be any ordinary synthetic fiber, but among them, polyester yarn or polyamide fiber yarn is suitable. In addition, aromatic polyamide, polyethylene fiber, elastic fiber such as polyurethane, cellulosic fiber, etc., which are said to be highly functional fibers, can be preferably applied, and although not particularly limited, a high fiber of 6.5 cN / dtex or more is particularly preferable. Polyester yarn that can achieve strength is the most suitable. Polyester is preferred as polyethylene terephthalate.

  Further, in order to achieve the core yarn thread having the above average tensile strength of 4.0 cN / dtex, the average tensile breaking strength of the filament yarn is required to be 6.5 cN / dtex or more, and more preferably 7 cN / dtex or more. However, since it is difficult to produce a strength of 8 cN / dtex or more due to restrictions of the current technology, if the upper limit is deliberately set, it becomes 8 cN / dtex. Also, it is desirable that the filament yarn has a high strength at 10% elongation, that is, a so-called 10% modulus, which is related to the strong constitution of the core yarn thread. In other words, since the core yarn sewing thread is generally composed of filament yarns and sheath yarns consisting of short fibers, when determining the breaking strength of the core yarn sewing thread, the sheath yarn is first formed when the elongation is about 10%. Is broken, and then the core yarn with high elongation is broken. In short, the strength of the core yarn at the breaking elongation point (10% modulus) of the sheath yarn is related to the maximum strength of the core yarn, that is, the core yarn has a high strength of 10% modulus. The breaking strength as a sewing thread is also increased. The appropriate range of the 10% modulus is 5.5 to 7.0 cN / dtex, and if it is lower than this, the strength as a core yarn sewing thread naturally does not meet the requirement. On the other hand, if it is higher than this, it is technically possible, but the dry heat shrinkage rate is increased due to restrictions on the process conditions, and the shrinkage of the finished sewing thread also rises, so it is not preferable because puckering tends to occur during sewing. . The average tensile rupture strength and average tensile rupture elongation mentioned here are determined by the measurement method described later.

  Moreover, it is preferable that the dry heat shrinkage rate of the core yarn of the core-yarn composite fiber in the present invention is 5 to 8%. If the dry heat shrinkage is less than 5%, the 10% modulus of the core yarn cannot reach 5.5 cN / dtex or more. Further, if the dry heat shrinkage rate exceeds 10%, the above-described puckering problem is caused, which is not preferable.

  The total filament fineness of the filament yarn is preferably in the range of 30 to 200 dtex, and the number of single yarn filaments in the range of 12 to 200 is suitable. For example, it is more preferable that the filament yarn has a yarn configuration of 12 to 30 at 33 dtex, 15 to 28 at 44 dtex, 18 to 48 at 56 dtex, and 24 to 72 at 78 dtex. This is because when the single fiber fineness is increased, the core yarn sewing thread becomes harder and the seam is raised from the fabric. On the other hand, if it becomes thin, fluffing occurs or strength is reduced from the twisting process to the final finishing process, so it is necessary to select appropriately.

  Moreover, the cross-sectional shape of the filament yarn in the present invention is not particularly limited, and can be arbitrarily selected from known ones such as a round shape, a triangular shape, a hollow shape, and a bimetal type.

  As the sheath yarn of the core yarn composite fiber, not only the usual synthetic fiber as well as the core yarn, but polyester and polyamide are suitable among them, and natural fibers such as cotton, wool, silk or cellulose or acrylic fiber, etc. Can also be preferably applied. In the present invention, the short fiber constituting the sheath yarn is a raw material for spun yarn, a futon cotton, a stuffed cotton, etc., and as a specific form, a staple fiber or simply called a staple Etc.

  The average tensile breaking strength of the short fiber used in the present invention is preferably 6.0 to 8.0 cN / dtex. If the average tensile breaking strength of the short fibers is less than 6.0 cN / dtex, sufficient strength cannot be obtained, and this may cause a breakage of the stitches at the time of sewing or seams. On the contrary, if the average tensile strength at break of short fibers exceeds 8.0 cN / dtex, when the fluff generated by friction of the seams becomes pilling, the short fibers are too strong and the pilling is difficult to fall off, which is not preferable. The average tensile rupture strength mentioned here is obtained by a measurement method described later.

  As the short fiber, the single fiber fineness is preferably in the range of 0.5 to 1.2 dtex, and the range of 0.7 to 1.0 dtex is the spinning property such as card passing property, the covering property of the sheath yarn in the core yarn composite fiber, or The softness of the core yarn sewing thread leads to high sewability, which is more preferable. When the single fiber fineness is less than 0.5 dtex, fluff is likely to occur and the quality of the core yarn sewing thread is lowered, which is not preferable. On the other hand, when the single fiber fineness exceeds 1.2 dtex, the number of cross-sectional configurations of the sheath yarn is small, the covering property of the sheath yarn is deteriorated, and it is easy to be caused by a thread defect such as a slab. Therefore, it is not preferable.

  Moreover, the dry heat shrinkage rate of the short fiber used in the present invention is preferably 2.0 to 6.5%. If the dry heat shrinkage ratio is less than 2.0, the elongation is hardly changed by dyeing, which is not preferable because the initial elongation is small and causes stitch skip. On the contrary, if the dry heat shrinkage rate exceeds 6.5%, the initial elongation after dyeing becomes too large, and puckering tends to occur after sewing, which is not preferable. The dry heat shrinkage mentioned here is determined by the measurement method described later.

  In addition, the fiber length of the short fiber in the present invention is not particularly limited, and can be arbitrarily selected from normal fibers, particularly fiber lengths usually used as staple fibers.

The cross-sectional shape of the short fiber in the present invention is not particularly limited, and can be arbitrarily selected from known ones such as a round shape, a triangular shape, a Y shape, a hollow shape, and a bimetal (side-by-side) shape.
The short fiber that is the sheath yarn of the core yarn composite fiber of the present invention is preferably in the range of 30% to 60% with respect to the total weight of the core yarn composite fiber including the core yarn. If it is less than 30%, the core yarn is likely to be exposed, and the strength is also lowered, so that winding defects and unraveling are likely to occur, and formation when a core yarn sewing thread is made becomes insufficient. On the other hand, if it exceeds 60%, the core yarn is not exposed, but the strength reduction tends to be large.

  As a method for measuring the weight of the sheath yarn, a 1-inch (2.54 cm) long core yarn sewing thread is disassembled into a core yarn composite fiber using a magnifying glass as necessary, and then the core yarn composite fiber is used as a core yarn. It decomposes | disassembles into a sheath yarn, and also takes out only the short fiber around which a sheath yarn is wound, and measures the weight (g). The weight is calculated as a weight ratio with respect to the total weight of the core yarn sewing thread.

  Here, the form of the core yarn composite fiber in this invention is demonstrated in detail. As a method for winding the sheath yarn around the core yarn of the core yarn, it is preferable that the short fiber yarn of the sheath yarn is tightly wound in the length direction of the core yarn and swirled around the entire surface. In this case, there is almost no exposure of the core yarn, and the sheath yarn is uniformly wound in a certain direction and tightly wound on the entire surface, so that the binding force becomes strong and a preferable shape can be formed as a core yarn sewing thread. As described above, the core yarn composite fiber that is tightly wound around the entire surface in a certain direction has a feature that the core yarn composite fiber is substantially untwisted and has almost no torque although the sheath yarn is wound.

  As the winding direction of the sheath yarn, since the final use is a sewing thread, the S direction is preferable in the same way as the twisting direction of a general sewing thread. That is, the core yarn sewing thread of the present invention has a structure in which a plurality of core yarn composite fibers in which the lower twist is inserted in the same direction as the yarn winding direction are aligned and the upper twist is inserted in the Z direction opposite to the lower twist. A core yarn thread is a preferred embodiment.

A preferable range of the number of lower twists Ts (T / m) inserted in the core yarn composite fiber in the present invention is 0 ≦ Ts ≦ 12000 / D ^1/2 . A lower twist number Ts is more suitable as the softness of the yarn, but conversely, if it is too small, the fiber conjugation property is deteriorated and the sewing property is lowered. On the other hand, when the number of lower twists Ts exceeds 12000 / D1 / ² , it is possible to improve the sewability, but it is not preferable because the formed yarn becomes rigid. Therefore, a more preferable range is 2000 / D ^1/2 ≦ Ts ≦ 10000 / D ^1/2 . D is the fineness (dtex) of the core yarn composite fiber.

The core yarn sewing thread of the present invention is a core yarn sewing thread in which a plurality of yarns are combined and then an upper twist having a relationship of the following formula is further applied after the core yarn composite fiber is provided with a lower twist. The upper twist number Tu (T / m) is preferably in the range of 2000 / Dt ^1/2 ≦ Tu ≦ 20000 / Dt ^1/2 . If the number of upper twists Tu exceeds 20000 / D ^1/2 , the strength decreases greatly and the sewing property decreases. Conversely, if the number of upper twists Tu is less than 2000 / Dt ^1/2 , the gap between fibers becomes large, and the sewing needle during sewing This is not preferable because it causes thread breakage. A more preferable range is 6000 / Dt ^1/2 ≦ Tu ≦ 15000 / Dt ^1/2 . Here, Dt indicated here is the fineness of the sewing thread.

  Since the sheath yarn of the core yarn composite fiber is uniformly and tightly wound, the winding is strong, so that the convergence is higher than the conventional product. In addition, since the number of fluff is extremely small as compared with the conventional ring spinning core yarn, the core yarn has an excellent effect that the appearance and seam of the yarn are beautifully finished. Furthermore, the softness of the yarn that could not be realized by pneumatic spinning can be obtained, which solves the above problems at a stretch.

  Further, the number of fluffs of the core yarn sewing thread is preferably in the range of 500 pieces / 10 m or less. Here, the number of fluff means what was measured by the measuring method mentioned below. When the number is 500 pieces / 10 m or less, it is possible to prevent fuzz and the like from being conspicuous and to maintain the quality of the seam. Further, the lower limit is preferably as small as possible, but if it is too small, it is not preferable because the heat dissipated by the needle heat does not go well during sewing, which affects the high-speed stitchability. On the other hand, if it exceeds 500 pieces / 10 m, the slipping characteristics become unstable and the skipping and thread breakage tend to increase. Further, the sewing thread becomes too conspicuous due to fuzz and the like, and the quality of the seam is deteriorated. Furthermore, 15 pieces / 10 m or more is more preferable.

  Moreover, it is preferable that the number of fluff of 3 mm or more and less than 5 mm is 3/10 m or more. Moreover, it is preferable that it is 80 piece / 10m or less, More preferably, it is 50 piece / 10m or less. When the number of fluff of 3 mm or more and less than 5 mm is less than 3/10 m, the effect of dissipating needle heat at the time of sewing is low, which causes a thread breakage, which is not preferable. On the other hand, if the number of fluff of 3 mm or more and less than 5 mm is more than 80/10 m, the variation in strength is increased, which leads to troubles such as thread breakage during sewing, which is not preferable.

  Moreover, it is preferable that the fuzz of 5 mm or more is 50/10 m or less. When the number of fluffs of 5 mm or more exceeds 50/10 m, it is not preferable because strong variation increases and causes thread breakage during sewing or at the seam.

In addition, the softness of the sewing thread is also required in order to cope with a wide range of sewability that can be used not only for industrial purposes but also for household sewing threads. By producing the core yarn sewing thread of the present invention by the fine spinning method described above, it was possible to achieve a bending hardness of 0.005 gfcm ² / piece or less and a bending recovery of 0.006 gfcm / piece or less. Also, if it is too soft, complicated patterns such as zigzag stitches such as zigzag stitches will be sewn, and the upper thread will not be able to save the lower thread well, and a yarn jumping phenomenon will occur. Therefore, the normal bending hardness is 0.001 gfcm ² or more. The bending recovery property is preferably 0.001 gfcm / piece or more. The bending characteristics and bend recovery properties mentioned here are determined by the measurement method described later.

  Hereafter, the manufacturing method of the core yarn sewing thread of this invention is demonstrated in detail.

  As a spinning method for producing the core yarn composite fiber in the present invention, a general-purpose air fine fiber is formed by binding the staple sliver after the drawing process of the spinning process, that is, using a short fiber bundle, to form a spun yarn by the action of air flow. In the spinning machine, the filament is supplied to the center of the short fiber bundle before the yarn forming section through maintenance of long fibers such as an appropriate feed roller and yarn path guide, and the core yarn made of the filaments by the swirling airflow in the S direction. A method obtained by air spinning while the short fibers are entangled with each other can be preferably used.

  Particularly preferred is a method using “Murata Vortex Spinner” (Murata Machine Co., Ltd .: hereinafter referred to as MVS). Various spinning methods that utilize the action of airflow have been proposed, developed, and used. However, in order to obtain the core yarn composite fiber used in the present invention, it is important that the coverage is good, and MVS is used. The spinning method used is one of the spinning methods that can achieve this most.

Next, the obtained core yarn composite fiber is temporarily twisted in the same direction as the swirl direction, and a plurality of the obtained core yarn composite fibers are aligned, and an upper twist in the direction opposite to the lower twist direction is applied. The inventive core yarn thread can be produced. At this time, the preferred lower twist number Ts (T / m) and upper twist number Tu (T / m) are as described above.
0 ≦ Ts ≦ 12000 / D ^1/2
2000 / Dt ^1/2 ≦ Tu ≦ 20000 / Dt ^1/2
(Where D is the fineness (dtex) of the core yarn sewing thread, and Dt is the fineness (dtex) of the core yarn composite fiber)
It is.

Here, when the number of lower twists Ts exceeds 12000 / D1 / ² , the yarn becomes stiff and the bending property of the yarn tends to be high. When sewing, the slack of the lower thread is reduced, and the formed loop is also reduced. Therefore, there is a case where the tip of the kama sword does not pick up the lower thread, and skipping easily occurs, so that it is not possible to cope with a complicated sewing pattern.

In addition, when the preferred range of the number of upper twists is less than 2000 / Dt ^1/2 , the convergence is lowered, the strength is greatly lowered, and the sewability is lowered. On the other hand, insertion exceeding 20000 / Dt ^1/2 is not preferable because the thread becomes stiff and leads to deterioration of the sewing property.

  Here, when the upper twist is applied, it is preferable that two or three core yarn composite fibers are combined and subjected to an upper twist to obtain a twisted yarn. If the number is less than 2, it is not preferable because strength as a sewing thread cannot be obtained, and thread breakage may occur during sewing. On the other hand, if the number is 4 or more, it is difficult to apply the upper twist, and the uniformity of the yarn tends to be impaired and the sewing property tends to be lowered.

  The method for imparting the lower twist and the upper twist in the production method of the present invention is not particularly limited, and can be arbitrarily selected from ordinary methods such as a double twister and a down twister.

  In the production method of the present invention, it is preferable to dye the cheese after obtaining the core yarn sewing thread. The method of cheese dyeing is not particularly limited, and can be arbitrarily selected from methods such as dyeing with disperse dyes and cationic dyeing.

  Moreover, in the manufacturing method of this invention, it is preferable to provide a finishing oil agent after cheese dyeing. The method of applying the finishing oil is not particularly limited, but an oil applying method using an oiling roller that generates less fluff and does not have to worry about sucking up the excess oil is more preferable.

  In addition, the type of finishing oil in the production method of the present invention is not particularly limited and can be arbitrarily selected from known finishing oils, but a finishing oil mainly composed of silicon is used from the viewpoint of good smoothness and low cost. It is more preferable.

  Hereinafter, the present invention will be described in more detail with reference to examples.

  The measurement method was as follows.

(1) Apparent fineness (dtex)
Based on JIS L1013 (1999), it measured 20 times per level and calculated the average value.

(2) Average tensile breaking strength (cN), average tensile breaking strength (cN / dtex), average tensile breaking elongation (%)
The measurement was carried out 20 times per grabbing length of 200 mm, tensile speed of 100% / min, and the average tensile breaking strength and average tensile breaking elongation were obtained using STATIMA ME manufactured by Keiki Keiki Co., Ltd. Moreover, the average tensile breaking strength was calculated from the apparent fineness.

(3) 10% modulus (cN / dtex)
The 10% modulus can be obtained from the stress (vertical axis) -strain (horizontal axis) curve obtained by the above measurement. The method draws a vertical line to 10% strain on the horizontal axis indicating the strain, obtains the stress corresponding to the stress-strain curve, further calculates the strength from the apparent fineness, and the strength at that time is 10% modulus ( cN / dtex).

(4) Dry heat shrinkage (%), Boiling yield (%)
The dry heat shrinkage (%) was measured by shrinkage at 180 ° C. according to JIS L1013 (1999).

  Moreover, the boiling yield (%) measured shrinkage | contraction at 98 degreeC based on JISL1013 (1999).

(5) Number of fuzz (pieces / 10m)
Using an electrostatic capacitor while unwinding at a speed of 30 m / min, the number of surface fluff protruding from 1 mm, 3 mm, 5 mm or more was counted for each yarn diameter. The data in the table is the number of fluff per 10 m length (pieces / 10 m), and is an average value measured 10 times for each fluff length.

  In addition, according to JIS L1095 (1999) (general spun yarn test method) 9.22 B method, the measuring apparatus measured using Shikishima Techno Co., Ltd. F-INDEX TESTER.

(6) U%
Measurement was performed using an EVENNESS TESTER 80 manufactured by Keiki Co., Ltd.

(7) Amount of wrapping sheath yarn (% by weight)
Using a magnifying glass, 1 inch (2.54 cm) long core yarn is broken down into core yarn composite fiber, then the core yarn composite fiber is broken down into core yarn and sheath yarn, and only the short fiber wound with sheath yarn is wound. Take out and measure its weight (g). The weight is calculated as a weight ratio with respect to the total weight of the core yarn sewing thread.

(8) Coverability evaluation Evaluation was made by observing the side surfaces of the obtained long and short composite spun yarns with a 25-fold microscope and judging the number of locations where the filaments of the core portion can be confirmed from the surface layer portion per 1 m of yarn length.

  Judgment criteria were four-step evaluation: x: 10 or more places or occurrence of nude yarn, Δ: 5-9 places, ◯: 1-4 places, OO: 0 places.

(9) Bending properties (bending hardness, recoverability)
Measurement was performed using KES-FB manufactured by Kato Tech Co., Ltd. 60 yarns are used for one measurement, and the bending hardness and recoverability per piece are calculated by division.

(10) Sewing property evaluation method High-speed sewability (advanced sewing): The maximum number of rotations (needle / min) that can be sewn without thread breakage was measured with a sewing machine capable of sewing 10 sheets of T / C broad fabric and sewing 2m. Measurements were tested in the range of 1000 to 5000 (needle / min).

B. Back sewability (back stitching): Four T / C broad fabrics were stacked, and the number of thread breaks (average number / 10 times) when sewing 1 m at 1500 (needle / min) with a sewing machine was measured. The evaluation criteria were as follows.
×: Sewing is not possible or 6 times or more Δ: 3-5 times ○: 1-2 times ○○: 0 times.

C. Zigzag stitch sewing (household use): Two T / C broad fabrics are stacked, and the stitch defects (mesh skipping) when 0.5m is sewn with zigzag stitch (sewing pitch 1.4mm, zigzag width: 4mm) on a sewing machine. The number of occurrences of defective seams) was measured. The number of needle rotations was 300 spm (stitch / min). The evaluation criteria were as follows.
X: 6 times or more Δ: 3-5 times ○: 1-2 times ○○: 0 times.

D. Seam quality: Samples sewn at a rotational speed of 1000 (needle / min) were visually evaluated in the high-speed sewability (advanced stitching) evaluation in Section A.
Δ: Lots of fluff.
○: Fluff can be found.
○○: Fuzz is hardly noticeable.

Examples 1, 2 and 3
Using an average tensile breaking strength of 6.4 cN / dtex, a single fiber fineness of 0.8 dtex, a fiber length of 38 mm, and a dry heat shrinkage of 6%, using a polyethylene terephthalate polyester staple, a normal spinning method, A sliver was produced.

  Also, a homo-PET having an intrinsic viscosity (IV) of 0.67 ± 0.02 is melted, discharged at a spinning temperature of 300 ° C. with a 36-hole die, taken up at a spinning speed of 1000 m / min, and an undrawn yarn of 336T-36f UY was obtained. Furthermore, using a three-stage hot roll drawing machine, the hot roll temperature was 75 ° C. and the total draw ratio was 6 times. A drawn filament of 36 filaments was obtained. Both the spinning and the drawing had good yarn-making properties, and no yarn breakage occurred.

  The filament yarn obtained had an average tensile strength at break of 7.2 cN / dtex, a 10% modulus of 6.4 cN / dtex, and a dry heat shrinkage at 150 ° C. of 7%.

  Next, the obtained sliver is mounted on an MVS spinning machine, and the filament is fed from the front top roller to the second top roller to the center position in the width direction of the short fiber bundle through the filament feed roller device and the yarn path guide. A core yarn composite fiber having a cotton count of 60'S was obtained at a spinning speed of 200 m / min and a total draft of 184 times. This core yarn composite fiber had an appearance as shown in FIG. 1, was excellent in covering properties, had little yarn breakage, and had good spinnability.

  In order to produce a core yarn sewing thread by twisting three of the core yarn composite fibers, the core yarn composite fiber has a base twist number of 200 T / m (Example 1), 600 T / m (Example 2), 1000 T / m ( Example 3) Next, three yarns were aligned and the number of upper twists was 700 T / m in the Z direction to produce a triple yarn core yarn sewing thread.

  Next, a triple twisted core yarn is wound around cheese and subjected to a steam set at 95 ° C. for 30 minutes as a twist-preventing treatment, then wound onto soft cheese, scoured at 60 ° C. for 10 minutes, relaxed, and then at 130 ° C. The cheese is dyed for 40 minutes at the end, finished in black, and then finished with a finishing oil GS-100SH manufactured by Takamatsu Yushi Co., Ltd. at 3.0% o. w. The core yarn sewing thread was manufactured by applying f. The properties of the obtained core yarn sewing thread and the results of the sewability evaluation are shown in Table 1 described later.

Comparative Example 1
The single fiber fineness of polyester multifilament (44 dtex-18 filament) having an average tensile breaking strength of 6.2 cN / dtex of the long fiber yarn serving as the core yarn and the polyester raw cotton of the short fiber bundle serving as the sheath yarn is 1.3 dtex, A core yarn sewing thread was finished in the same manner as in Example 1 except that the fiber length was 38 mm. The properties of the obtained core yarn sewing thread and the results of the sewability evaluation are shown in Table 1 described later.

Comparative Example 2
A core yarn sewing thread was finished in the same manner as in Example 1 except that the single fiber fineness of the polyester raw cotton of the short fiber bundle serving as the sheath yarn was 1.3 dtex and the fiber length was 38 mm. The properties of the obtained core yarn sewing thread and the results of the sewability evaluation are shown in Table 1 described later.

Comparative Example 3
Next, using the same filament yarn and short fiber bundle as in Example 1, a core yarn composite fiber having a cotton count of 60S was obtained by ordinary ring spinning with the same number of twists as in Example 1, and Example 1 and A core yarn thread was finished in the same manner. The properties of the obtained core yarn sewing thread and the results of the sewability evaluation are shown in Table 1 described later.

  As shown in Table 1, Examples 1 to 3 have excellent performance in all industrial applications such as high-speed sewing and automatic machine compatibility. Furthermore, it was possible to cope with complicated zigzag stitches used for home use. Moreover, the finish of the seam was beautiful.

  In Comparative Example 1, since the average tensile breaking strength of the raw yarn used for the core yarn is relatively low at 6.2 cN / dtex, when the core yarn is finished, the strength as the sewing yarn is reduced, and high speed is possible. Sewability was slightly low. In Comparative Example 2, since the single fiber fineness of the raw cotton used for the sheath yarn is 1.3 dtex, the number of cross-sectional configurations of the sheath yarn is reduced in order to make a sewing thread as in Examples 1 to 3, and the sheath In the yarn coverage evaluation, some nude yarn was seen, which was a bad result. Therefore, during sewing, thread breakage occurred at a place where the covering was bad, and the operation was interrupted. In Comparative Example 3, since a normal spinning method is used, fluffs are conspicuous on the surface of the seam.

  For general garments that require high-speed sewing for industrial use, automatic machine-compatible sewing, back sewing, and clean seams that can handle complex patterns such as zigzag stitches for home use, for example, long and short composite yarns As a result, it can be applied to luxury women's clothing and men's pants that take advantage of its excellent elasticity and waist texture.

It is an external appearance schematic diagram of the core yarn composite fiber produced in the Example.

Explanation of symbols

1: Filament yarn (long fiber yarn) of core yarn part
2: Short fiber yarns in sheath 3: Fluff 4: Loop

Claims (4)

Around the filament yarn that becomes the core yarn, a short fiber that becomes the sheath yarn is wound at a total weight ratio of 30% to 60%. A core yarn sewing thread in which an upper twist is applied in the opposite direction to the lower twist direction, with an average tensile breaking strength of 4.0 cN / dtex or more, a bending hardness of 0.005 gfcm ² or less, and a bending recovery of 0 .006 gfcm / core or less. The filament yarn has an average tensile breaking strength of 6.5 to 8.0 cN / dtex, a 10% modulus of 5.5 to 7.0 cN / dtex, and a dry heat shrinkage at 150 ° C. of 5 to 8%. The core yarn sewing thread according to claim 1, wherein: The short fibers have an average tensile breaking strength of 6.0 to 8.0 cN / dtex, a single fiber fineness of 0.5 to 1.2 dtex, and a dry heat shrinkage at 180 ° C. of 2.0 to 6.5%. The core yarn sewing thread according to claim 1 or 2, wherein the core yarn sewing thread is provided. In the spinning process, the short fiber drafted by the swirling airflow is entangled around the filament yarn, and then twisted in the same twisting direction as the winding direction to obtain a core yarn composite fiber, and further the core yarn composite fiber The method for producing a core yarn sewing thread according to any one of claims 1 to 3, wherein a plurality of yarns are aligned and subjected to an upper twist.

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