JP2005220497A - Elastic cylindrical weft knitted braid and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an elastic braid, having a good touch feeling, without showing any uncomfortable feeling even on making a contact with the skin directly, and further capable of being produced by using a usual cylindrical weft knitter in a good productivity. <P>SOLUTION: This elastic cylindrical weft-knitted braid is knitted by using a side by side type or sheath core type composite polyester-based fiber having an eccentric core and containing a layer consisting mainly of a polytrimethylene terephthalate at least as one layer, or a composite elastic yarn constituted by using a polyurethane elastic fiber and a non-elastic yarn as the elastic material, and also has ≥30 % elongation rate. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a cylindrical horizontal knitted string having an elongation rate of 30% or more. More specifically, as a stretchable material, a polyester-based composite fiber of a side-by-side type composite or an eccentric seascore type composite including at least one layer mainly composed of polytrimethylene terephthalate and / or polyurethane elastic fiber and non-stretchable The present invention relates to a stretchable tubular weft braid knitted by a small diameter tubular weft knitting machine of 5 inches or less using a composite stretchable elastic yarn composed of a stretchable yarn.

  Conventionally, as an elastic string, a polyester-type polyurethane extruded into a film and then slit into an elastomer tape, a rubber thread or a core of a polyurethane elastic fiber, a synthetic fiber such as a polyester fiber or a polyamide fiber, Processed yarn strings such as multiple covering yarns and twisted yarns wound with modified cellulose fibers or the like as sheath yarns, braided cords manufactured by a string making machine using polyurethane elastic fibers, and the like have been used.

  Of these elastic cords that have been produced in the past, elastomer tape cords made of polyester polyurethane film in the form of tapes are used in applications that come in direct contact with the human body, such as mask cords. The skin was congested after prolonged contact. In addition, the sticky tactile sensation was uncomfortable.

  Further, in the case of a processed yarn string such as a multiple covering yarn using rubber yarn or polyurethane elastic fiber as a core yarn, the elongation rate is large, but there are various problems.

  That is, the multiple covering yarn was obtained after double covering with a normal covering machine a synthetic yarn such as polyester fiber or polyamide fiber or a sheath yarn of modified cellulose fiber on the core yarn of polyurethane elastic fiber. This is a multi-covered elastic yarn obtained by further covering the covered elastic yarn with the sheath yarn or the like, which requires a multi-step covering process and has a problem of low productivity. In addition, twisted unevenness (yarn shift) of the coated yarn is likely to occur, and the twist balance is likely to be non-uniform so that snare is likely to occur. Further, when the winding tension of the coated yarn around the core yarn is increased to prevent twist unevenness (yarn deviation), there arises a problem that the texture of the obtained coated elastic yarn becomes hard. Further, since the sheath yarn is easily untwisted from the yarn end, there is a problem that the use loss is large.

  Further, in the case of a string made of twisted yarn, there is a problem that uneven coating tends to occur, and rubber threads and polyurethane elastic fibers are exposed on the surface of the string, and the skin contact tends to deteriorate.

  Further, in the case of an elastomer tape, a rubber thread, or a coated thread string coated on the core of polyurethane elastic fiber, there has been a problem that the elastomer tape itself or the core thread deteriorates due to use and deterioration over time. In addition, in the case of a string of rubber yarn covering yarn or polyurethane elastic fiber covering yarn, there has been a problem that the core rubber yarn or polyurethane elastic fiber is exposed on the surface of the cord due to use or poor coating, and the cord strength is greatly reduced.

  In addition, stretchable braids manufactured by a string making machine using polyurethane elastic fibers have very good stretchability and texture, but only one cord can be produced per head, resulting in poor production efficiency and cost. There was the inconvenience of becoming high.

  Further, Patent Document 1 proposes a method of improving the knitting method to increase the stretch rate of the knitted fabric and further producing a stretchable tubular knitted string using a wooly processed yarn. However, this method increases stretchability by the way of knitting, and the knitting method introduces an eyelet guide through which the yarn is fed out after being guided to the knitting cord machine body through a tension guide that gives the yarn a certain needle condition. In conjunction with the left and right guide headers turning alternately, a plurality of spatula needles located at the bottom of the guide header move up and down to knit a cylindrical braid.

However, since this method increases stretchability by adopting a special knitting method, there is a problem that knitting work is not easy and productivity and workability are inferior. In addition, since the yarn used is a woolen processed yarn, the stretchability is not so high, and it has been difficult to obtain a stretchability that can be replaced by an elastic elastic string of rubber or polyurethane.
Japanese Patent Laid-Open No. 9-158812

Elastic strings are used in a wide range of applications, and various properties are required.
For example, in the case of use where the human skin is in direct contact with a thin part such as a mask string or a head cap rubber string, there is an elongation rate of 30% or more, and the tightening force is soft, and the skin To make the contact surface soft, the string diameter or width is 1 mm or more, the texture of the string is soft, yellowing does not change during storage and use, and processing agents and resins that cause skin damage when contacting the skin adhere Furthermore, it is required not to give a sense of incongruity or discomfort during use.

However, it has been difficult for the above-described conventional stretchable cords to satisfy these required characteristics.
Therefore, the present invention can solve the problems of the conventional stretchable string, has a good texture, does not feel uncomfortable even when directly touching the skin, and is produced using a normal cylindrical weft knitting machine. An object of the present invention is to provide an elastic string that can be manufactured with good performance. In particular, an object of the present invention is to provide a stretchable string that can satisfy the required characteristics such as the mask string and the head cap rubber string described above.

  In order to achieve the above object, the present invention provides a polyester-based composite fiber of a side-by-side type composite or an eccentric seascore type composite containing at least one layer mainly composed of polytrimethylene terephthalate as a stretchable material, and / or Alternatively, by using a composite elastic elastic yarn composed of polyurethane elastic fibers and other non-stretchable yarns, and having a horizontal knitting machine with an ordinary cylindrical weft knitting machine, it has a stretchability of 30% or more. A cylindrical horizontal braided string is manufactured.

  That is, the above-described composite fibers and composite elastic elastic yarns are suitable as elastic materials for increasing the elasticity of the cylindrical horizontal knitted string to a desired level from the viewpoint that the elongation rate can be easily adjusted. In addition, in the case of stretchable cords that are used under conditions that are subject to abrasion and are subject to wear in harsh environments and require durability, the polyester-based composite fibers excellent in durability, heat resistance, etc. Particularly suitable as a material, and in the case of a stretchable cord used in applications requiring a soft texture and a high elongation rate, the composite stretchable elastic yarn is particularly suitable as a stretchable material.

  As described above, the stretchable cord of the present invention is a side-by-side composite or eccentric structure that is a knitted cord that is knitted in a cylindrical shape, and includes at least one layer mainly composed of polytrimethylene terephthalate as a stretchable material. It is knitted using a seascore-type composite polyester-based composite fiber or a composite stretch elastic yarn composed of polyurethane elastic fiber and non-stretch yarn, and has an elongation of 30% or more. To do.

  The stretchable cylindrical weft braid of the present invention is sufficiently stretchable, has a good texture, and does not feel uncomfortable even if it comes into direct contact with the skin, and is produced using a normal tubular weft knitting machine. It is an elastic string that can be manufactured with good performance. Furthermore, by selecting the knitting density, the number of needles, and the diameter of the knitting machine, it is possible to adjust the elongation ratio, texture, and string diameter to a desired level. Furthermore, at the time of knitting, knitting is performed by combining yarns having different properties, such as stretchable material for imparting elongation, water-absorbing yarn for imparting water absorption, yarn for imparting surface change, and the like. It is also possible to devise the string form and string function according to the application. Furthermore, the stretchable cylindrical weft braid of the present invention can be easily produced because it can be manufactured by a normal cylindrical weft knitting machine.

  The stretchable cylindrical weft braid of the present invention is a stretchable braid knitted by a tubular weft knitting machine, and includes at least one layer containing polytrimethylene terephthalate as a main component as a stretchable material side by side Polyester type composite fiber of type composite or eccentric sea core type composite and / or composite elastic elastic yarn composed of polyurethane elastic fiber and other non-elastic yarns are used.

  The polyester composite fiber used as the stretchable material is a polyester composite fiber of a side-by-side type composite or an eccentric sea core type composite containing at least one layer mainly composed of polytrimethylene terephthalate. The polyester-based composite fiber is a polyester-based composite fiber in which a layer mainly composed of polyethylene terephthalate and a layer mainly composed of polytrimethylene terephthalate are combined in a side-by-side type or an eccentric sea core type. preferable.

  The polyester-based composite fiber is a combination of polyethylene terephthalate and polytrimethylene terephthalate, and different polymers having different intrinsic viscosities η are bonded together. Therefore, stress is concentrated on the high viscosity side in the spinning and drawing processes. The internal distortion between the two components is different, and it is latent crimpable. Therefore, the high-viscosity side is greatly shrunk due to the difference in elastic recovery rate after stretching and the heat shrinkage difference in the heat treatment process of the fabric, and distortion occurs in the single fiber to develop a form of three-dimensional coil crimp. The diameter of this three-dimensional coil and the number of coils per single fiber length largely depend on the shrinkage difference (including the elastic recovery rate difference) between the high shrinkage polymer layer and the low shrinkage polymer layer, and the coil diameter increases as the shrinkage difference increases. Smaller and more coils per unit fiber length.

  The coil crimping characteristics required for stretchable materials include a small coil diameter and a large number of coils per unit fiber length (because of excellent stretch characteristics and good appearance), and good coil sag resistance. (Since the amount of coil sag according to the number of expansions and contractions is small and the stretch retention is excellent). Furthermore, since the expansion / contraction characteristics of the coil are dominated by the expansion / contraction characteristics of the high contraction component with the low contraction component as a fulcrum, the polymer used for the high contraction component is required to have high extensibility and recoverability.

  In order to obtain excellent coil crimp characteristics without detracting from the excellent characteristics of polyester, it is effective that the low shrinkage polymer layer is mainly composed of polyethylene terephthalate and the high shrinkage polymer layer is mainly composed of polytrimethylene terephthalate. It is. This is because polytrimethylene terephthalate fibers have mechanical properties and chemical properties equivalent to those of typical polyester fibers such as polyethylene terephthalate fibers and polybutylene terephthalate fibers, and are extremely excellent in stretch recovery. This is because in the crystal structure of polytrimethylene terephthalate, the methylene chain of the alkylene glycol part has a gouache Gauche structure (the molecular chain bends at 90 degrees), and is further constrained by the interaction between benzene rings (stacking, parallel) This is probably because the molecular chain easily expands and recovers due to the rotation of the methylene group because the point density is low and the flexibility is high.

  Polyethylene terephthalate, which is the main component of the low-shrinkage polymer layer in the polyester-based composite fiber, is a polymer having ethylene terephthalate units as main repeating units. That is, this polyethylene terephthalate is a polyester obtained using terephthalic acid as the main acid component and ethylene glycol as the main glycol component. However, the copolymerization component which can form another ester bond may be contained in the ratio of 20 mol% or less. What is contained in the ratio of 10 mol% or less is more preferable. Examples of the copolymerizable compound include sulfonic acid, sodium sulfonic acid, sulfuric acid, sulfuric acid ester, ethyl sulfate, ethyl sulfate, aliphatic sulfonic acid, ethanesulfonic acid, chlorobenzenesulfonic acid, alicyclic sulfonic acid, isophthalic acid, sebacin Acid, azelaic acid, dimer acid, adipic acid, oxalic acid, decanedicarboxylic acid and other dicarboxylic acids, p-hydroxybenzoic acid, ε-caprolactone and other hydroxycarboxylic acids, triethylene glycol, polyethylene glycol, propanediol, butanediol, Diols such as pentanediol, hydroquinone and bisphenol A are preferably used.

  Further, if necessary, titanium dioxide serving as a matting agent, fine particles of silica or alumina as a lubricant, hindered phenol derivatives, coloring pigments or the like as an antioxidant may be added.

  Polytrimethylene terephthalate, which is a main constituent of the high-shrinkage polymer layer in the polyester-based composite fiber, is a polymer having trimethylene terephthalate units as main repeating units. That is, this polytrimethylene terephthalate is a polyester obtained using terephthalic acid as the main acid component and 1,3 propanediol as the main glycol component. However, the copolymerization component which can form another ester bond may be contained in the ratio of 20 mol% or less. What is contained in the ratio of 10 mol% or less is more preferable. Examples of copolymerizable compounds include dicarboxylic acids such as isophthalic acid, succinic acid, cyclohexanedicarboxylic acid, adipic acid, dimer acid, sebacic acid, and 5-sodium sulfoisophthalic acid, ethylene glycol, diethylene glycol, butanediol, and neopentyl glycol. Diols such as cyclohexanedimethanol, polyethylene glycol and polypropylene glycol are preferably used.

  Further, if necessary, titanium dioxide serving as a matting agent, fine particles of silica or alumina as a lubricant, hindered phenol derivatives, coloring pigments or the like as an antioxidant may be added.

  The polyester-based conjugate fiber used in the present invention is obtained by compounding the above-described two types of polymers into a side-by-side type or an eccentric sheath / core type at the time of melt spinning. If it is not a composite of such a side-by-side type or an eccentric sea core type, when heat is applied to the yarn, coiled crimps do not appear, and the yarn cannot be provided with elasticity.

  In the case of a side-by-side type composite, the single yarn cross-sectional shape may be a round cross-section, but is preferably a deformed cross-sectional shape. Examples of the deformed cross-sectional shape include a non-circular shape such as an eyebrow shape and a snowman shape, and a deformed circular shape such as an ellipse. In the case of an eyebrows-shaped or snowman-shaped cross-sectional shape, a composite shape in which approximately round polymer layers are connected is taken.

  In addition, the weight ratio of polyethylene terephthalate / polytrimethylene terephthalate in the polyester-based composite fiber is (30/70) or more and (70/30) or less from the viewpoint of yarn production and dimensional uniformity of the coil in the fiber length direction. A range is preferable.

  The yarn composed of the polyester composite fiber generally has a yarn fineness of 15 dtex or more and 660 dtex or less, and the single yarn fineness of the polyester composite fiber is 0.4 dtex or more and 25 dtex or less. A range is preferred.

  When supplying the yarn composed of this polyester composite fiber to the cylindrical weft knitting machine as a knitting yarn, one yarn composed of a plurality of filaments may be used as it is, or a yarn in which two or more yarns are aligned. Alternatively, a twisted yarn may be used. The yarn fineness of the knitting yarn may be appropriately selected depending on the intended use of the string to be produced, but is generally preferably 15 to 660 decitex.

  Further, the yarn composed of the polyester-based composite fiber may be a raw yarn or a processed yarn subjected to Woolley processing for the purpose of fine crimping, and further subjected to relaxation heat treatment, that is, DDW processing for the purpose of improving the elongation rate. A processed yarn may be used, and there is no restriction on the presence or absence of the processing and the form. Further, a colored yarn such as a yarn dyed by yarn dyeing may be used.

  As the composite stretchable elastic yarn composed of polyurethane elastic fiber and other non-stretchable yarn used as a stretchable material in the stretchable cylindrical weft braid of the present invention, the polyurethane elastic yarn has other non-stretchable yarn. Those twisted by a covering machine, a twisting machine or a spinning machine are preferred. That is, it may be a covering yarn such as a single covering yarn or a double covering yarn in which polyurethane elastic fibers are covered with other non-stretch yarns in a covering machine. It may be a twisted yarn that has been made, or a core-spun yarn manufactured by a spinning machine.

  The polyurethane elastic fiber used here may be a general polyurethane elastic fiber, and a polyester-based or polyether-based polyurethane elastic fiber is preferably used.

  In addition, there is no particular limitation on the non-stretchable yarn used together with the polyurethane elastic fiber, natural vegetable fiber such as cotton and hemp, natural animal fiber such as wool, regenerated fiber such as rayon, semi-synthetic fiber such as cellulose acetate, Synthetic fibers such as modified cellulose, polyester fibers, and polyamide fibers can be used. These may be long fibers or short fibers, and a single type of yarn or a plurality of types of yarns may be used.

  When these non-stretchable yarns are long fibers, the state of use may be either raw yarn (raw yarn), temporary twisted yarn or yarn dyed yarn. In the case of a short fiber, it may be a spun yarn or a dyed yarn.

  The fineness of the polyurethane elastic fiber, the draft, the fineness of the other non-stretchable yarn, the number of twists, and the like may be appropriately set according to the necessary stretchability and texture.

  For example, when it is desired to increase the power feeling of the stretchable cylindrical weft braid obtained, the fineness of the polyurethane elastic fiber may be increased, or the draft may be increased within a range not causing yarn breakage. The fineness of the polyurethane elastic fiber may be appropriately set as described above, but is preferably in the range of 15 to 235 dtex. The draft is also preferably in the range of 2.8 to 4.8, more preferably in the range of 3.0 to 4.5, and still more preferably in the range of 3.5 to 4.0.

  In addition, since the stretchable cylindrical weft braid of the present invention is a cord manufactured by weft-knitting into a tubular shape, even with a fine yarn, a stretchable cord having a relatively large cross-sectional diameter can do. In addition, when using a covering yarn in which polyurethane elastic fibers are covered with long fibers, if the number of single yarns of the covering long fiber yarns is increased and the single yarn fineness is reduced, the softness of the large cross-sectional diameter is increased. It can be an elastic string. For example, when using 83 dtex yarn of polyester long fiber as the covering yarn, the feeling of swelling, cross-sectional diameter, and softness is greater when using a filament number of 72 filaments than using a filament number of 24 filaments. growing.

  The stretchable cylindrical weft braid of the present invention may be knitted by the above-described stretchable material alone, or may be knitted by mixing other yarns for the purpose of providing a function.

  That is, the polyester-based composite fiber may be knitted alone, or the polyurethane elastic fiber and another non-stretchable yarn may be knitted alone, or the polyurethane elastic fiber may be knitted. Two types of composite elastic elastic yarns composed of other non-stretchable yarns and the polyester-based composite fibers may be mixed for knitting. Further, at least one of the elastic materials and other non-stretchable yarns may be used. You may knit together using strips.

  The stretchable cylindrical weft braid of the present invention may generally have a constituent yarn in the range of 1 to 5, but in this case, at least one of them may be the stretchable material. .

  There are no particular restrictions on the type of other non-stretchable yarns used in combination with the above stretchable materials. Natural vegetable fibers such as cotton and hemp, natural animal fibers such as wool, regenerated fibers such as rayon, cellulose acetate, etc. Semi-synthetic fibers, modified cellulose, synthetic fibers such as polyester fibers and polyamide fibers can be used. Further, these may be long fibers or short fibers, and in the case of long fibers, processed yarns subjected to processing such as Woolley processing may be used. A single type of yarn or a mixture of a plurality of types of yarn may be used. Furthermore, these other non-stretchable yarns may be pre-dyed yarns.

  For example, when cotton fibers and hemp are mixed as other non-stretchable yarns, water absorption can be imparted to the stretchable cylindrical weft braid of the present invention. The advantage that it absorbs can be given.

  When the elastic material and other yarns are mixed, it is preferable that the mixing ratio of the elastic material is 20% or more so as not to impair the excellent elasticity of the elastic cylindrical horizontal knitted string. More specifically, when the polyester-based composite fiber is used as an elastic material, the mixing ratio is preferably 50% or more. When a composite elastic elastic yarn composed of polyurethane elastic fiber and other non-elastic yarn is used, The mixing ratio is preferably 20% or more.

  The stretchable cylindrical weft braid of the present invention can be manufactured by a normal cylindrical weft knitting machine, and by setting the knitting conditions of the tubular weft knitting appropriately, the stitches of the knitted string are dense, texture, and stretched. The rate, thickness, etc. can be designed arbitrarily. In order to form a cylindrical weft braid, the number of knitting needles is preferably in the range of 50 or less, the cam diameter is preferably in the range of 5 inches or less, and the number of yarn feeding ports is preferably in the range of 5 or less. Various weft braids can be designed by increasing / decreasing within the range or increasing / decreasing the winding speed. Moreover, the performance of the stretchable cylindrical weft braid obtained by changing the number of cams to one or more can be changed.

  Moreover, although the diameter of a cylindrical horizontal braided string should just be decided according to the use, it is generally 1 mm or more, for example, should just be 1-5 mm.

  The stretchable tubular horizontal knitted cord of the present invention has sufficient stretchability even when it is knitted, but it is also possible to develop stretchability by applying relaxation heat treatment. In addition, in the state where the relaxation heat treatment is not performed, the relaxation heat treatment is performed after unwinding from the wound state of cheese, corn, etc., and therefore it is preferable to perform the relaxation heat treatment from the viewpoint of reducing the shrinkage rate. The relaxation heat treatment in this case may be dry heat treatment, wet heat treatment, or in-liquid treatment, and the heat treatment mode and heat treatment method are not particularly limited as long as the stretchability of the stretchable material is not impaired.

  For example, when a composite elastic elastic yarn composed of polyurethane elastic fibers and other non-elastic yarn is used as the elastic material, the dry heat treatment temperature is preferably 120 ° C. or higher in order to exert the effect of producing elasticity by heat treatment. In order not to cause thermal deterioration of the polyurethane elastic fiber, the temperature is preferably 160 ° C. or lower. The dry heat treatment time is preferably 10 seconds or more and 60 seconds or less. This is because if the treatment time is less than 10 seconds, the relaxation heat treatment effect cannot be obtained, and if it exceeds 60 seconds, there is a concern about power reduction.

  When a composite elastic elastic yarn composed of polyurethane elastic fiber and other non-elastic yarn is used as the elastic material, the wet heat treatment temperature is in the range of 100 ° C. or higher and 130 ° C. or lower from the same viewpoint as the dry heat treatment. preferable. The wet heat treatment time is preferably 1 second or more and 20 seconds or less.

  When using a composite elastic elastic yarn composed of polyurethane elastic fiber and other non-elastic yarn as an elastic material, the treatment temperature in liquid is in the range of 60 ° C. or higher and 100 ° C. or lower from the same viewpoint as dry heat treatment. Is preferred. The treatment time in the liquid is preferably 1 second or more and 120 seconds or less.

  The relaxation rate in the relaxation heat treatment is preferably in the range of 40% to 120%.

  In order to develop a uniform heat treatment effect on the stretchable cylindrical weft braid of the present invention, it is preferable to perform heat treatment in a relaxed state of free or casserole rather than a tension state wound around corn or cheese. In addition, when heat treatment is performed in a tension state, the stretchability is reduced due to the heat set effect, and therefore, relaxation heat treatment that does not apply a load is preferable.

  Moreover, when using the said polyester-type composite fiber as an elastic | stretch material, what is necessary is just to give relaxation heat processing on the conditions equivalent to the composite elastic elastic yarn comprised with the polyurethane elastic fiber and the other non-expandable thread.

  The stretchable cylindrical weft braid of the present invention that can be obtained in this way is excellent in stretchability with an elongation rate of 30% or more.

The measurement of the elongation rate of this cylindrical weft braid was performed under the following conditions.
One end of the cylindrical weft braid was gripped, and marking was performed at a position 50 cm in length from the gripping position with a 0.2 g load applied to the other end. Next, the length L to the marking position 60 seconds after the load on the other end side was changed to a load of 100 g was measured. The elongation rate was determined by the following formula. In addition, the result was obtained as an average value of 10 at each level.

  Elongation rate = [(L-50) / 50] × 100 (%)

  Examples of the present invention will be described below, but the present invention is not limited thereto.

[Example 1]
Using a string knitting machine (3 mm diameter × 4 needles × 1 neck) manufactured by Sakurai Textile Machinery Co., Ltd., Toray Co., Ltd. polyester-based composite fiber T-400 (polytrimethylene terephthalate / polyethylene terephthalate composite ratio = 50 / 50. Side-by-side composite. The same applies to the following.) Using two double yarns of 56 dtex yarn as the constituent yarns, a normal cylindrical weft knitting was performed, and a cylindrical weft braid was knitted.

  Various characteristics of the obtained stretchable cylindrical weft braid were as shown in Table 1. That is, it was a stretchable cylindrical weft braid with a high bulkiness index, a low bending resistance, and a soft bulkiness. The elongation rate was maintained at 80% and had sufficient stretchability.

[Example 2]
Using a twin knitting yarn of 56 dtex of polyester-based composite fiber T-400 made by Toray Industries, Ltd. as a constituent yarn using a string knitting machine (3 mm diameter × 6 needles × 1 neck) manufactured by Sakurai Textile Machinery Using 100%, a normal cylindrical weft knitting was performed, and a cylindrical weft braid was knitted.

  Various characteristics of the obtained stretchable cylindrical weft braid were as shown in Table 1. That is, it was a stretchable cylindrical weft braid having a high bulkiness index and a low bending resistance and being bulky and soft. The elongation rate was maintained at 50% and had sufficient stretchability.

[Example 3]
Using a string knitting machine (3 mm diameter × 4 needles × 1 neck) manufactured by Sakurai Textile Machinery Co., Ltd., 56% of Toray Co., Ltd. polyester-based composite fiber T-400 56 dtex yarn is used as the constituent yarn. Used, 44% cotton spun yarn was used as a constituent yarn, and knitted alternately to form a tubular horizontal knitted string.

  Various characteristics of the obtained stretchable cylindrical weft braid were as shown in Table 1. That is, it was a bulky and soft cylindrical weft braid with a high bulkiness index and a low bending resistance. The elongation rate was kept at 40% and had sufficient stretchability. Moreover, since the cotton yarn was knitted as the constituent yarn, an elastic tubular horizontal knitted string having water absorption could be obtained.

[Example 4]
Using a string knitting machine (3 mm diameter × 6 needles × 1 neck) manufactured by Sakurai Textile Machinery Co., Ltd., a 44 dtex yarn of polyurethane elastic fiber (LYCRA (registered trademark) manufactured by Operontex Co., Ltd.) and polyethylene manufactured by Toray Industries, Inc. Covering yarn (SCY), which is a single covering of terephthalate filament yarn (83 dtex, 24 filaments), was used as a constituent yarn 100%, and ordinary cylindrical weft knitting was performed to form a tubular weft braid.

  Various characteristics of the obtained stretchable cylindrical weft braid were as shown in Table 1. That is, it was a stretchable cylindrical weft braid having a high bulkiness index and a low bending resistance and being bulky and soft. The elongation rate was maintained at 90% and had sufficient elasticity.

[Example 5]
Using a string knitting machine (3 mm diameter × 4 needles × 1 neck) manufactured by Sakurai Textile Machinery Co., Ltd., polyurethane elastic fiber (LYCRA (registered trademark) 44 dtex manufactured by Operontex Co., Ltd.) and polyethylene terephthalate manufactured by Toray Industries, Inc. A covering yarn (SCY), which is a single covering of filament yarn (83 dtex, 72 filaments), was used as a constituent yarn, and a normal cylindrical weft knitting was performed, and a cylindrical weft braid was knitted.

  Various characteristics of the obtained stretchable cylindrical weft braid were as shown in Table 1. That is, it was a stretchable cylindrical weft braid having a high bulkiness index and a low bending resistance and being bulky and soft. The elongation rate was 360%, and it had high stretchability.

[Example 6]
The cylindrical weft braid knitted in Example 5 was subjected to a relaxation heat treatment with steam at 120 ° C. for 30 seconds.
Various characteristics of the obtained relaxation heat-treated cylindrical weft braid were as shown in Table 1. That is, it was a stretchable cylindrical weft braid having a high bulkiness index and a low bending resistance and being bulky and soft. The elongation was 420%, and it had high stretchability.

[Comparative Example 1]
Using a covering machine manufactured by Kataoka Machine Industry Co., Ltd., 920 dtex yarn of polyurethane elastic fiber (LYCRA (registered trademark) manufactured by Operontex Co., Ltd.), nylon filament yarn (235 dtex) at the lower twist, and polyethylene terephthalate filament yarn at the upper twist (330 dtex) was double covered with a draft 3.5, and a polyethylene terephthalate filament yarn (330 dtex) was further covered thereon to produce a triple covered elastic composite elastic yarn.

  The obtained stretchable composite elastic yarn had a string-like thickness and had good stretchability. However, the bulkiness index was low, the bending resistance was high, and the string was hard. Although the elongation was very large at 140%, the twist unevenness was conspicuous and the appearance quality was inferior.

  In Table 1, the string diameter describes the diameter under a load of 0.20 g. The bulk height index was obtained by (diameter / weight per unit area). The bending resistance was measured according to the 45 ° cantilever method (JIS-L1096 6.19 bending resistance A method).

  The stretchable cylindrical weft braid of the present invention is a stretchable cord having a bulkiness and an elongation rate of 30% or more, is soft to the skin, and can be applied to a direct contact with the human body. It can be used for a string, a cap string and the like.

Claims (10)

A side-by-side composite or eccentric seascore composite polyester-based composite fiber that is a knitted string that is knitted in a cylindrical shape and includes at least one layer mainly composed of polytrimethylene terephthalate as an elastic material. Stretchable cylindrical weft braid characterized by having a stretch rate of 30% or more. The stretchable cylindrical weft braid according to claim 1, wherein the polyester-based composite fiber is a composite fiber composed of a polytrimethylene terephthalate layer and a polyethylene terephthalate layer. The stretchable cylindrical weft knitting according to claim 1 or 2, wherein a weight ratio of the polytrimethylene terephthalate layer and the polyethylene terephthalate layer of the polyester composite fiber is in a range of 70/30 to 30/70. string. A braided string knitted in a cylindrical shape, knitted using a composite elastic elastic yarn composed of polyurethane elastic fiber and non-elastic yarn as an elastic material, and an elongation rate of 30% or more An elastic tubular horizontal braided string characterized by comprising: The composite stretchable elastic yarn is a single covering yarn or double covering yarn in which a polyurethane elastic fiber is covered with a non-stretchable yarn, a twisted yarn composed of a polyurethane elastic fiber yarn and a non-stretchable yarn, or a polyurethane elastic fiber is not a non-stretchable yarn. The stretchable cylindrical weft braid according to claim 4, wherein the stretchable tubular weft braid is one of core-spun yarns coated with stretchable short fibers. The elastic cylindrical weft braid according to any one of claims 1 to 5, wherein the fineness of the knitting yarn made of an elastic material is 15 to 660 dtex. The stretchable cylindrical weft according to any one of claims 1 to 6, wherein the number of knitting yarns constituting the knitted string is in the range of 1 to 5 and at least one is a knitting yarn made of the stretchable material. Braided string. A yarn composed of a polyester-based composite fiber of a side-by-side type composite or an eccentric sea core type composite containing at least one layer mainly composed of polytrimethylene terephthalate, and / or a polyurethane elastic fiber and a non-stretchable yarn A stretchable cylindrical weft braid characterized by knitting with a small-diameter cylindrical weft knitting machine using a configured composite elastic elastic yarn and having 50 or fewer needles and a cylinder diameter of 5 inches or less Production method. The method for producing a stretchable tubular weft braid according to claim 8, wherein the number of yarns fed to the tubular weft knitting machine is 5 or less. A method for producing a stretchable cylindrical weft braid, comprising subjecting a cord knitted by the method according to claim 8 or 9 to a relaxation heat treatment.