JP2006132038A - Core yarn sewing thread - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a high-quality core yarn sewing thread that is suitable for sewing by using an industrial lock-stitch sewing machine, has high-speed sewability, unnoticed difference in dyeing between a core yarn and fibers of a sheath part, unnoticed fluff of seam after sewing and proper stretchability. <P>SOLUTION: The core yarn sewing thread is obtained by using a plurality of core yarns in which an inside sheath part which staple fibers enclose in a cylindrical state in parallel in the length direction of the core yarn composed of an elastic filament is formed and an outside sheath part which comprises staple fibers winding and enclosing the outside layer of the inside sheath part is formed. A core yarn in which the outside sheath part is composed of a part of the staple fibers of the inside sheath part is suitably used. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a core yarn sewing thread excellent in stretchability and sewability.

  Conventionally, core yarn sewing yarns are composed of core yarn fibers made of long fibers and sheath yarn fibers made of drafted short fiber yarns, which are fed to the front roller of the spinning machine, where compound spinning and lower twisting yarns are simultaneously applied. A long and short composite yarn core yarn is manufactured, and a plurality of the core yarns are aligned, and an upper twist is applied in a direction opposite to the twist direction of the composite spinning.

  The core yarn has a high strength and good stitchability compared to a span thread having a span thread ratio of 100%, and its production volume has increased rapidly in recent years. However, since the short fiber ends are conspicuous as fluff because the short fiber is used for the sheath thread, the quality of the seam is low, especially when used as a sewing thread for sewing filament filament fabrics, etc. Has a problem that the cost is not torn because the raw material cost of the core yarn sewing thread is added due to the lack of quality and the use of long fibers as the core yarn.

  Therefore, "polyester mixed twist sewing thread" consisting of composite yarns with a twisted structure in which long fiber yarns that have already been twisted and spun yarns that have already been spun are aligned and twisted together with a joint machine. It has been proposed (see Patent Document 1). This polyester mixed twist sewing thread is a reasonably manufactured mixed twist sewing thread, but because the long fiber yarn may be arranged in the outer layer on the combined twist structure, the sewing property is low, and the long fiber yarn Since there are differences in dyeing and gloss with the spun yarn, the quality of the core yarn sewing thread was low.

  In addition, core filaments that have been electrospread by static electricity are evenly distributed within the cross section of the short fibers that form the sheath yarn, and core yarns are produced by composite spinning, and several core yarns are aligned. A “composite sewing thread” with an upper twist has been proposed (see Patent Document 2). This composite sewing thread is excellent in sewing properties and uniform dyeing properties, but has a low production quality because it passes through an electric opening process, resulting in an increase in manufacturing cost and a conspicuous fluff.

  In recent years, the development of sewing threads, the speeding up of sewing machines and the automation of sewing machines have progressed, and the sewing technology for items of sewing products has also improved. Under such circumstances, for example, sewing of jeans and the like, durability of seam strength is required, and in thin blouses and the like, stretchability is required in addition to the beautifulness of seams. The above-mentioned seam strength is strong and good-looking, and the required characteristics of the sewing thread to achieve this are high strength, fine count and stretchability.

  Furthermore, a core yarn manufacturing apparatus and a core yarn manufacturing method (see Patent Document 3), a two-layer structure yarn and a manufacturing method thereof (see Patent Document 4) have been proposed. These proposals use a core yarn manufacturing apparatus provided with a spinning section including a hollow guide shaft body in which a yarn passage is formed in the nozzle axial direction and a swirl flow generating nozzle that causes a swirl flow to act on the tip portion thereof. This is a technique for producing a core yarn while bundling short fibers around the long fibers supplied to the spinning section together with the drafted short fiber bundles.

None of these proposals, however, mentions core yarn spinning as an applied technology, especially with regard to the development of sewing threads, and there is no suggestion, and the sewing thread has excellent fineness, high strength characteristics, and excellent sewing properties and quality. This technology has not been developed.
Japanese Patent Laid-Open No. 02-33341 Japanese Patent Publication No. 63-3777 JP 2002-69760 A JP 2002-69774 A

  Therefore, in view of the background of the prior art, the object of the present invention is particularly suitable when sewing using an industrial lockstitch machine, is excellent in high-speed sewing, and the dyeing difference between the core yarn and the sheath yarn is not noticeable. An object of the present invention is to provide a high-quality core yarn sewing thread in which the fluff of a stitch after sewing is not conspicuous and has an appropriate stretch property.

  The present invention employs the following means in order to solve such problems.

  That is, in the core yarn sewing thread of the present invention, in the length direction of the core yarn made of elastic long fibers, the short fibers are surrounded in a cylindrical shape to form an inner sheath portion, and the short fibers are wound around the outer layer to surround the outer side. A core yarn sewing thread comprising a plurality of core yarns having sheath portions formed therein.

  One of the preferred embodiments of the core yarn sewing thread of the present invention is that the outer sheath portion is constituted by a part of the short fibers of the inner sheath portion.

One of the preferred embodiments of the core yarn sewing thread of the present invention is that the weight ratio of the outer sheath portion is 10 to 30% by weight of the total weight of the core yarn.
Moreover, one of the preferable aspects of the core yarn sewing thread of the present invention is that the elongation rate is 20 to 50% and the elongation elastic modulus is 40 to 90%.

According to the present invention, when sewing using an industrial lockstitch sewing machine, it is excellent in high-speed sewing, the dyeing difference between the core thread and the sheath thread is not noticeable, and the fluff of the stitches after sewing is not noticeable. In addition, it is possible to provide a high-quality stretch core yarn sewing thread having an appropriate stretch property.
As an article to be sewn, it is suitable for applications requiring particularly stretch properties such as jeans and uniforms for general clothing.

  The inventors of the present invention have intensively studied and identified a core yarn sewing thread that has few yarn breaks during high-speed sewing, a difference in dyeing between the core yarn and the sheath yarn of the core yarn is inconspicuous, has high fluff quality, and has an appropriate stretch property. When a plurality of substantially twisted core yarns having a structure are stretched and twisted together to create a sewing thread, it has been found that a sewing thread that can solve such a problem can be provided at once.

  The components of the stretchable core yarn sewing thread of the present invention will be described. First, the stretchable core yarn that constitutes the stretchable core yarn sewing thread is characterized in that the long and short composite yarns are substantially twisted and have no actual twist.

  In the core yarn used in the present invention, as the elastic long fibers used for the core yarn, synthetic fibers such as polyester and polyamide are preferable, and polyester-based synthetic fibers such as polyethylene terephthalate, polytrimethylene terephthalate, and polybutylene terephthalate are particularly suitable. Yes. Further, as the polyamide-based synthetic fiber, those having a high elastic property such as nylon 6 or nylon 66 are suitable. Moreover, a polyurethane-type synthetic fiber can be used as a highly elastic long fiber.

  In the present invention, the elasticity of the elastic long fiber refers to a fiber having an elastic recovery rate of at least 50% at 10% elongation.

  On the other hand, as the short fibers constituting the sheath, synthetic fibers such as polyethylene terephthalate and polyamide, cellulosic fibers such as rayon, bamboo fiber and acetate, natural fibers such as cotton, silk and wool, or biodegradable Fiber etc. are mentioned. Moreover, you may use for the short fiber which comprises a sheath part, combining the elastic short fiber of the same material as a core thread | yarn.

  When using a polyester fiber for the core yarn, it is preferable to use the same polyester-based short fiber or natural fiber for the sheath yarn from the viewpoint of dyeing conditions. This is advantageous in that the same bath dyeing is possible, the same recipe is possible, and the same color can be dyed.

  Next, the yarn structure of the core yarn used in the present invention will be described. The core yarn used in the present invention forms an inner sheath portion in which short fibers are surrounded in parallel with a core yarn made of elastic long fibers in a core portion. Here, “parallel” means a state in which the short fibers of the inner sheath part are arranged substantially in the same direction as the length direction of the core yarn and surround the core yarn.

  On the outside of the two-layer structure thus configured, the remaining single fibers of the short fibers wrap around the entire inner sheath part to surround the inner sheath part to form the outer sheath part, thereby forming a three-layer structure as a whole. To do. That is, the cross-sectional configuration of the core yarn used in the present invention has a core yarn in the center, and the core fiber is covered with the short fibers of the inner sheath portion in parallel, and the outer sheath portion is wound around the outer sheath of the inner sheath portion. Is a substantially twisted structure with no actual twist as a whole. Here, the substantially twisted structure is a structure that does not contain actual twist.

  “Substantially no twist” generally means that the twist becomes zero per unit length even if the thread has a slight twist or twist in the thread length direction. Per unit length generally refers to 1 m.

  The core yarn sewing thread of the present invention is a core yarn sewing thread that is formed by aligning a plurality of substantially twisted core yarns and further applying an upper twist.

  The winding state of the short fiber of the outer sheath part in the present invention will be described more specifically. The angle between the short fiber of the outer sheath part and the winding direction is preferably 20 to 70. Wound in a range of degrees. When the winding angle is less than 20 degrees on the average, the winding and binding force is lowered and unplugging occurs, and the spinning property tends to be greatly reduced. In addition, when the winding angle exceeds 70 degrees on average, the winding and binding force increases, but the winding thickness unevenness occurs and the spinning property tends to decrease. The most preferable winding angle for spinning and yarn formation is in the range of 30 to 60 degrees on average.

  In addition, it is preferable that the short fibers are wound at substantially the same angle in the same direction and wound at substantially the same pitch and have no randomness.

  The measurement of the wrapping angle is obtained by measuring 10 angles of wrapping fibers contained per inch from a yarn form photograph taken at a magnification of 40 times with a scanning electron microscope, and calculating an average value thereof.

  In the present invention, it is preferable that the short fiber of the outer sheath portion is tightly wound. The state of tight winding is that the entire surface is uniformly coated to the extent that the core yarn is hardly visible through the outer sheath portion. This is because no dyeing irregularity is observed between the elastic long fibers of the core yarn and the short fibers of the sheath when dyed.

  Furthermore, although the short fiber of the outer sheath portion is wound, the actual twist is not inserted, and the wound core-sheath structure is formed substantially without twisting.

In the core yarn used in the present invention, the weight ratio of the short fibers of the outer sheath portion to be wound is preferably 10 to 30% by weight of the total weight of the core yarn. When the weight ratio of the short fibers of the outer sheath portion to be wound is less than 10%, the covering property is poor and the core yarn is exposed or visible from the short fiber gaps of the sheath portion group. It becomes a conspicuous problem as the color difference and irritability of the core yarn of the part and the fiber of the sheath part. On the other hand, when the weight ratio exceeds 30%, the amount of sheath yarn is increased, and there is no problem of color difference or irritation, but the strength against the thickness of the core yarn sewing thread is reduced, and the thread processability is lowered. Moreover, the ratio of the short fiber of an inner sheath part becomes larger than the ratio of an outer sheath part.
The core yarn sewing thread of the present invention is formed by arranging a plurality of the above core yarns and twisting them. Specifically, the core yarn is subjected to a lower twist, a plurality of core yarns are aligned, and the upper twist is applied to form a sewing thread.

  The elongation percentage of the core yarn sewing thread of the present invention is preferably 20 to 50%, and the elongation elastic modulus is preferably 40 to 90%. Normally, the core yarn sewing thread is designed to have an appropriate rigidity and little elongation from the viewpoint of forming a sewing loop, but if there is stretchability, the rigidity becomes low and the loop formability is lowered, so the sewing property is low. Generally, it tends to decrease. However, the stretchable core yarn sewing thread of the present invention has characteristics of moderate hardness, stretchability and high elongation elastic modulus.

  Specifically, the core yarn sewing thread of the present invention is suitable for an elongation of 20 to 50%, and when the elongation is less than 20%, the elongation is small and the stretchability of the seam is insufficient, and the elongation is 50. If it exceeds%, it will be stretched too much, so the sewing properties will tend to deteriorate.

    Further, the elongation elastic modulus at which the elongation is recovered after the core yarn sewing thread is once stretched is preferably 40 to 90%. If the elongation elastic modulus is less than 40%, the elastic modulus is too low, so that the seam may be stretched out. is there. Further, if the elastic modulus of elasticity exceeds 90%, the recoverability of the stitches by the sewing thread is better than the recoverability of the fabric, and puckering may occur in a thin ground. In short, it is most preferable to have a stretch / elastic property that is compatible with the fabric and that stretches with the fabric and elastically recovers with the fabric.

  Next, if the mode for carrying out the present invention is described more preferably, since the core yarn does not have an actual twist, in order to obtain a normal thread structure, it is intended to prevent twist cracking and improve the yarn strength. The lower twist to be applied is preferably in a very small range of half or less of a normal sewing thread. In addition, the stretchable core yarn sewing thread in which a plurality of core yarns are aligned and twisted is more entangled between the core yarns as the number of lower twists inserted into the core yarn is smaller, and the phenomenon called twisting back and twisting is known. In particular, the back stitching and the automatic machine sewing are excellent in terms of sewing properties.

  If the lower twist applied to the core yarn is inserted to the same extent as the core yarn manufactured by ordinary ring spinning, the core yarn is already focused, which is not preferable because it easily hardens and significantly reduces the sewing property. However, in consideration of the upper twist processability and the further uniformity of the thread after the upper twist, it is possible to insert a certain amount of the lower twist.

That is, the lower twist number T is preferably such that the lower twist is inserted as 8000 / D ^1/2 ≧ T ≧ 0 (t / m), where D is the total fineness (dtex) of the core yarn. The sewing is more suitable.

Here, if the lower twist is inserted more than 8000 / D ^1/2 , the sewing performance is significantly reduced, and particularly in back sewing and automatic machine sewing, thread breakage frequently occurs or high-speed sewing is reduced. Show the trend.

  For example, in a core yarn having a total fineness of the core yarn of 70 dtex and a total fineness of the sheath portion equivalent to 130 dtex of 200 dtex, the sewing property is lowered when the lower twist number is 570 T / m or more, but less than 500 t / m. If it becomes, sewing property will improve. Speaking of preferred sewing properties, the lower the number of lower twists, the better. The condition that zero, that is, the number of lower twists is not applied is the best. In consideration of the uniformity, it is practically preferable to insert about 50 to 100 t / m.

As for the upper twist, the upper twist in the range applied to the normal sewing thread is applied. For example, in the same core yarn as described above, the total fineness of the core yarn is 70 dtex, the total fineness of the sheath yarn is equivalent to 130 dtex, and the total fineness is 200 dtex, and 500 t / m to 900 t in the Z direction opposite to the lower twist direction. The upper twist of / m is inserted.

  As for the twist direction inserted into the core yarn sewing thread of the present invention, the lower twist is inserted more smoothly in the direction in which the short fibers of the outer sheath part are wound around the elastic long fiber core thread. Therefore, the insertion direction of the upper twist is preferably inserted in the direction opposite to the lower twist because the torque balance is balanced.

  Normally, the combination of the lower twist and upper twist of the sewing thread from the needle rotating mechanism of the sewing machine is superior from the viewpoint of the sewing property that the lower twist is usually twisted in the S direction and the upper twist is twisted in the Z direction. When S is in the S direction, thread breakage during sewing may occur frequently.

  A multifilament is suitable for the elastic long fibers constituting the core yarn. The total fineness of the elastic long fibers constituting the core yarn is preferably in the range of 30 to 200 dtex, and the number of filaments in the range of 12 to 200 is suitable. For example, when the total fineness of the core yarn is 33 dtex, the number of filaments is 12 to 30, and when the total fineness of the core yarn is 78 dtex, the number of filaments is 24 to 72 and the total fineness of the core yarn is When the number of filaments is 200 dtex, the number of filaments is preferably 50 to 200 dtex.

  In relation to the total fineness and the number of filaments, if the filament single fiber fineness becomes thicker, the thread becomes harder and the stitches rise from the fabric, and if it becomes thinner, fluffing occurs and the strength decreases from the twisting process to the final finishing winding process. Therefore, the above range is a balanced condition.

  In addition, the larger the number of filaments, the more preferable the use of the core yarn, such as softening the bending and twisting properties of the core yarn, increasing the sewability and improving the puckering of the stitches. It may be difficult to be confused.

  Of course, it is possible to carry out with single fiber fineness and total fineness outside the above range, but it may cause various problems such as the beauty of the seam, durability or color matching with the fabric, so depending on the purpose and application Is to design.

  The elastic long fiber of the core yarn may be a single yarn made of 100% elastic fiber or a composite yarn obtained by compositely spinning an elastic fiber yarn and an inelastic fiber yarn, and may also be a side-by-side type or a core / sheath type composite yarn. Either is applicable. Specific examples include a side-by-side type composite yarn of elastic polypropylene terephthalate and inelastic polyethylene terephthalate, and a core / sheath concentric composite yarn using elastic polypropylene terephthalate fiber as the core yarn and non-elastic polyethylene terephthalate fiber as the sheath yarn. is there. When the above-mentioned side-by-side type composite yarn or core / sheath concentric type composite yarn is applied to the core yarn sewing yarn of the present invention, the former has a slightly better sewability than the latter, but the stretchability tends to be slightly inferior.

  The yarn structure of the core yarn uses elastic long fibers in the core portion as described above, and thus has high stretchability and high elasticity characteristics while being a core yarn, and therefore has high stretchability.

  As the characteristic of the elastic long fiber of the core yarn, the higher the cutting strength, the higher the sewing property. Therefore, the cutting strength is preferably at least 3 cN / dtex or more, more preferably 4 cN / dtex or more. Further, the boiling water shrinkage is preferably 6% or less, more preferably 3% or less in order to prevent puckering after sewing.

  In the raw cotton characteristics of the short fibers constituting the inner sheath portion and the outer sheath portion, the single fiber fineness is preferably in the range of 0.1 to 3 dtex, and the range of 0.5 to 1.5 dtex is the core yarn spinnability. Further, the smoothness of the thread lines of the core yarn sewing thread or the softness of the core yarn sewing thread leads to high sewability, which is a more preferable range.

  The fiber length of the short fiber may be either a short spinning type of 25 mm to 40 mm or a long spinning type of 38 mm to 70 mm, but the former is preferable in view of the cleanness of the core yarn sewing thread, and the high strength From the characteristics, the latter spinning method is preferable, and can be appropriately selected depending on the purpose.

  The number of short fibers in the inner sheath portion that are surrounded in parallel and the number in which the short fibers in the outer sheath portion are bundled and wound are preferably at least 40 in view of spinning process passability, spun yarn formation, spun yarn strength, etc. It is preferable that In addition, when the number exceeds 500, a phenomenon may occur in which the binding force decreases conversely. This number is the total number of short fibers of the inner sheath portion and the outer sheath portion in an arbitrary cross section of the core yarn sewing thread of the present invention.

  Next, the configuration of the core yarn sewing thread of the present invention will be described in detail with reference to the drawings. FIG. 1 is a side view showing an example of an appearance model of a core yarn used in the present invention.

FIG. 1 is an example of a yarn form of a core yarn before being subjected to a lower twist, and a short fiber 2 of an inner sheath portion around the elastic long fiber 1 of the core yarn forms a core yarn of the elastic long fiber 1 in a cylindrical shape. Surrounding in parallel, the short fiber 3 of the outer sheath is wound around the outside. There are fluff 4, sagging 5, and loop 6 on the surface of the core yarn.
FIG. 2 shows an example of the core yarn sewing thread of the present invention of the present invention in which two yarns having a lower twist are aligned on the core yarn and the upper twist is applied. The surface of the core yarn sewing thread is the outer side. Covered with short fibers 3 in the sheath, fluff 4 is shown. When the upper twist is twisted, the slack and loop disappear or become extremely small.

  Next, a method for producing the core yarn sewing thread of the present invention will be described. First, a staple fiber after the spinning step of the spinning process, that is, a bundle of short fibers, is used to sandwich a short fiber bundle disposed in the center of the feeding section of the spinning machine, and the short fiber bundle. Draft a short fiber bundle consisting of another short fiber bundle placed below the bundle, and then align the drafted short fiber bundle with the core of elastic long fibers released from the creel A stretchable core yarn is manufactured by supplying air to a spinning member using a swirling air flow, and performing an air spinning process without a short fiber bundle being entangled with a core yarn made of elastic long fibers. The processing speed in this spinning can be reasonably manufactured at a speed 10 to 30 times faster than that of a conventional ring spinning machine, and the manufacturing cost can be greatly reduced.

  Next, align the obtained core yarns and add an upper twist in the direction opposite to the direction wound by the swirling air flow, or lower the obtained core yarn in the same direction as the direction wound by the swirling air flow. The core yarn of the present invention can be manufactured by twisting, aligning a plurality of the stretchable core yarns obtained, and applying an upper twist in the direction opposite to the lower twist direction.

  The core yarn sewing thread of the present invention may be heat set for the purpose of stopping shrinkage or eliminating residual torque after the upper twist after the upper twist is applied. Subsequently, soft-wound cheese is prepared, cheese-dyed and cheese-dyed, and a stretch-dyed core yarn sewing thread is produced.

  The core yarn sewing thread of the present invention is particularly suitable as a sewing thread for sewing using an industrial main sewing machine.

  Hereinafter, the core yarn thread of the present invention will be described in more detail by way of examples. The characteristics used in the present invention are determined by the following measurement method.

(1) Fineness and strength:
Conforms to JIS L 1090 (1992).

(2) Elongation rate:
The length when the initial load of 0.1 CN / dtex is hung is measured and set as L1, and then the length when the constant load of 3 CN / dtex is hung is measured and set as L2, and the elongation is calculated by the following equation.
Elongation rate (%) = {(L2-L1) / L2} × 100.

(3) Elongation elastic modulus:
The length when the constant load 3CN / dtex is hung is measured and set to S1, and then the length when the initial load 0.1CN / dtex is hung is measured and set to S2, and the elongation elastic modulus is calculated by the following equation. Elongation elastic modulus (%) = {(S1-S2) / S1} × 100.

(4) Wound weight ratio of sheath yarn:
A 1-inch long core yarn sewing thread is collected, the upper twist is unwound, the lower twist thread is removed, the wound short fibers of the outer sheath portion are removed, and the weight W1 is measured. Separately, the weight WO of the core yarn sewing thread itself is measured, and the weight ratio is calculated by the following formula.
Weight ratio (%) = {(WO-W1) / WO} × 100.

(5) Sewing property:
Using a polyester fiber / cotton blend (T / C) broad cloth, the needle rotation speed of the sewing machine was changed, and forward stitching, back stitching and automatic machine sewing were tested. The sewing evaluation method is as follows.

・ High speed sewing:
Ten T / C broad fabrics are stacked, and a sewing test is performed in a range of maximum rotation of 1000 to 5000 (needle / min) by a sewing machine capable of sewing 2 m. High speed sewing
Evaluation was based on the number of thread breaks during sewing.
△; Thread break 2-5 times / 2m
○: Yarn break 1-2 times / 2m
・ Back stitching:
Four T / C broad fabrics are stacked, and this is evaluated by the number of thread breaks in 1m sewing (average number / n number = 10) at 1500 (needle / min).
×: Not sewing △; 2 to 5 times ○; ○ to 2 times ・ Automatic machine compatibility:
Four T / C broad fabrics are stacked, and this is evaluated in a tension range where sewing can be performed at 1500 (needle / minute) for 2 m.
×; Sewing not possible △; Sewing possible (tension range indefinite)
○: 100 to 200 g (the range in which the thread tension easily breaks when the sewing tension range is out of this range and cannot be sewn in the above figure)
-Seam quality: Visually evaluated.
×: Fluff can be found Δ; Fluff is hardly noticeable ○;

・ Stitch elongation:
When the seam was pulled with both hands in the lateral direction, the case where the seam was stretched by 10% or more was marked with ◯, the case where the seam was hardly stretched was marked with x, and the middle was marked with Δ.

-Comprehensive evaluation x: Unusable as a stretch sewing thread Δ; For example, even if the stitch quality for jeans is low, it does not matter if it has stretchability.
○: Practical (Example 1)
Using Murata Vortex Spinner Machine (Murata Machine Co., Ltd.), the core yarn has a strength of 4.4 cN / dtex, and the elastic modulus is 95% at 10% elongation and 91% at 20% elongation. Using a polytrimethylene terephthalate multifilament (78 dtex, 24 filament) long filament yarn and a polyester short fiber sliver with a single fiber fineness of 1.2 dtex and a fiber length of 38 mm as a sheath fiber. / Min, Nozzle pressure 0.55Mpa, Spindle diameter φ1.2, Overfeed rate 1-2%, Main draft 40 times, Total draft 140 times, Nozzle gauge 21mm, core yarn by swirling airflow spinning method wound in S direction Manufactured. In the obtained core yarn, polytrimethylene terephthalate multifilament yarn is present in the core yarn, and the outer peripheral portion of the core yarn is surrounded in a cylindrical shape substantially in parallel with the longitudinal direction of the yarn, and S is formed in the outermost layer. The winding angle in the direction was 55 to 60 degrees, forming a three-layer structure in which the above-described polyester short fibers wound around the entire surface were wound substantially without twisting.
In order to produce the obtained stretchable core yarn into a two-thread twisted thread, the lower twist number was set to 100 t / m, and the upper twist number was applied in the Z direction to 700 t / m in all to produce a two-core twisted core yarn thread. This two-core twist core yarn thread is rolled up on cheese to prevent twisting, steam set at 105 ° C for 20 minutes, then rolled onto soft cheese, washed with water and hot water at 60 ° C for 10 minutes. And then dyed cheese for 40 minutes at a temperature of 120 ° C., reduced to wash, washed with hot water and washed with water, finished in black, and produced an average winding angle of 55 to 57 degrees and a stretchable core yarn sewing thread of No. 36 2 . Table 1 shows the composition, characteristics, and sewability evaluation results of the stretchable core yarn thread.

(Comparative Example 1)
Elastic filaments of polytrimethylene terephthalate multifilament (78 dtex, 24 filaments) with a core yarn strength of 4.4 cN / dtex, elongation modulus of 95% at 10% elongation and 91% at 20% elongation I prepared the yarn. On the other hand, using a polyester short fiber sliver with a single fiber fineness of 1.2 dtex and a fiber length of 38 mm, a 60th single yarn spun yarn of 850 t / m in the S direction manufactured by ring spinning was manufactured. The obtained single yarn spun yarn was subjected to a wet heat treatment at 90 ° C. for 20 minutes to perform a twist setting. The resulting single yarn spun yarn and the above-mentioned elastic long fiber yarn are aligned, and a twist of 750 t / m in the Z direction is applied with a joint machine, followed by wet heat treatment at 105 ° C. for 20 minutes to stop the twist. Set. Subsequently, it is rolled up on soft cheese, washed with water and hot water at a temperature of 60 ° C for 10 minutes, dyed with cheese at a temperature of 120 ° C for 40 minutes, then washed with reduction, washed with water and washed with water to produce a black mixed yarn. However, the core yarn was visible between the spun yarns of the sheath yarn, and the coverage was poor. Table 1 shows the yarn configuration, characteristics, and sewability evaluation results of the mixed twist sewing yarn.

(Comparative Example 2)
Using a normal drawn yarn of polyethylene terephthalate multifilament (78 dtex, 24 filament) as the core yarn and a sliver similar to that in Example 1, a twist of 850 t / m in the S direction and a normal core yarn by ring spinning is used. Manufactured. The core yarn in the state where the pipe yarn was raised was subjected to wet heat treatment at 90 ° C. for 20 minutes to perform a twist setting. Two of the obtained core yarns were aligned and subjected to an upper twist of 820 t / m in the Z direction, and subjected to a wet heat treatment at 105 ° C. for 20 minutes to set the twist. Next, it is rolled up on soft cheese, washed with water and hot water for 10 minutes at a temperature of 60 ° C, dyed with cheese at a temperature of 130 ° C for 40 minutes, washed with reduction, washed with water and washed with water, and finished in black. A considerable amount of core yarn was produced, but there was little elasticity. Table 1 shows the thread configuration, characteristics, and sewability evaluation results of the core yarn sewing thread.

  The core yarn sewing thread of Example 1 is particularly excellent in stitch quality compared to the core yarn sewing thread of Comparative Example 1. This is because the core yarn is sufficiently covered with the short fibers of the sheath and is not exposed on the surface of the core yarn sewing thread. Therefore, the core yarn sewing thread of Example 1 is a high-quality stretch core yarn sewing thread that is unlikely to cause core / sheath irritation and dyeing differences due to dyeing. Further, in terms of seam elongation, the core yarn sewing thread of Comparative Example 2 hardly shows any stretch, and there is almost no seam elongation after sewing.

  Comparative Example 2 is a conventional ring-type core yarn sewing thread that is completely different from the thread structure of Example 1 and Comparative Example 1. However, the core thread is easily exposed from the fibers of the sheath, and the quality of the seam is low. It is low. Moreover, since it is based on a normal ring type, the fluff becomes conspicuous, leading to a decline in quality.

  According to the present invention, when sewing using an industrial lockstitch machine, excellent high-speed sewing is possible, the dyeing difference between the core yarn and the short fibers of the sheath portion is not noticeable, and the fluff of the stitches after sewing is conspicuous. It is possible to provide a high-quality stretch core yarn sewing which is difficult and has an appropriate stretch property.

  As an article to be sewn, it is suitable for applications requiring particularly stretch properties such as jeans and uniforms for general clothing.

FIG. 1 is a side view showing an example of an appearance model of a core yarn used in the present invention. FIG. 2 is a side view showing an example of an appearance model of the core yarn sewing thread of the present invention.

Explanation of symbols

1: Elastic long fiber of core yarn 2: Short fiber of inner sheath portion 3: Short fiber of outer sheath portion 4. Fluff 5: Slack 6: Loop

Claims (4)

In the length direction of the core yarn made of elastic long fibers, short fibers are surrounded in parallel in a cylindrical shape to form an inner sheath, and further, outer fibers are wound around the outer layer to form an outer sheath. A core yarn sewing thread characterized by using a plurality of yarns.   2. The core yarn sewing thread according to claim 1, wherein the outer sheath portion is constituted by a part of the short fibers of the inner sheath portion.   3. The core yarn sewing thread according to claim 1, wherein the weight ratio of the outer sheath portion is 10 to 30% by weight of the total weight of the core yarn. The core yarn sewing thread according to any one of claims 1 to 3, wherein an elongation percentage is 20 to 50% and an elongation elastic modulus is 40 to 90%.

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