JP4916818B2 - Method for producing double layer yarn - Google Patents

Description

The present invention relates to a method of manufacturing a multi-layer yarn.

  Conventionally, many chemical fibers / synthetic fibers have been produced and used in various fields by taking advantage of their respective fiber characteristics together with natural fibers. However, while the properties of each fiber are satisfactory in certain applications, the properties are often disadvantageous in other applications. For this purpose, these fibers are woven or blended as necessary to supplement the disadvantages of the characteristics and provide them for a desired use.

  A representative example is a multi-layer yarn obtained by spinning and twisting two kinds of short fiber groups in a spinning process which is the final process of the spinning process. For example, as an old multi-layered yarn, there is a multi-layered yarn in which a core portion is a polyester short fiber and a sheath portion is made of cotton (for example, see Patent Document 1). The woven or knitted fabric using the multi-layered yarn has a texture similar to that of the cotton woven knitted fabric and has iron setability, form stability and the like, and can be suitably used for uniform clothing.

The multi-layer yarn is not limited to one in which two types of fibers having different raw materials are arranged in the core portion and the other in the sheath portion, and fibers having the same raw material but different characteristics are arranged in the core portion and the sheath portion. There are also things. For example, Patent Document 2 discloses a multi-layer yarn in which one of two types of polyester short fibers having different single yarn fineness is arranged in the core portion and the other in the sheath portion. If this multi-layer yarn is used, A woven or knitted fabric with a soft feeling as well as a tight feeling can be obtained.
Japanese Patent Publication No.56-11775 Japanese Patent No. 2976790

  The spun yarn generally has a torque because it maintains the yarn form by twisting. Torque is a torsional moment generated in the untwisting direction. Generally, when the torque is strong, the form and quality of the woven or knitted fabric are adversely affected. Specifically, examples of adverse effects on the form include curling, skewing, and the like, such as curling, skew, traverse, and the like.

  The multi-layered yarn obtained by the above production method is common in structure with a general spun yarn made of a single raw material except that the short fibers constituting the core portion and the sheath portion are not the same. For this reason, the multi-layer yarn also has a torque like a general spun yarn.

  In order to reduce the torque of the spun yarn, it is a common means to use a twisted yarn so that the torque is offset between the upper twist and the lower twist. However, the yarn tends to be thicker by using the twisted yarn, and it tends to be difficult to obtain a woven or knitted fabric having an supple texture.

  On the other hand, non-twisted spun yarn having substantially no torque is known. Non-twisted spun yarn is obtained by using a twisted yarn obtained by cross-twisting a spun yarn made of water-insoluble fiber and a water-soluble fiber yarn in the direction opposite to the twisted direction of the spun yarn, and then water-soluble. It can be obtained by dissolving and removing the conductive fiber yarn. However, since such a twisted yarn has a torque, a problem similar to the above also occurs in a living machine made of the yarn. Such a problem cannot be solved by dissolving and removing the water-soluble fiber yarn to produce a non-twisted spun yarn.

  The present invention solves such problems, and can obtain a woven or knitted fabric having a stable form and excellent quality, and at the same time, has a multi-layered yarn that can contribute to improving the texture of the woven or knitted fabric while also providing excellent coverage. An object of the present invention is to provide a method for stably producing the multi-layer yarn.

  As a result of intensive studies to solve the above problems, the inventors of the present invention are multi-layer yarns composed of short fiber groups in both the core part and the sheath part, and the twist direction and twist coefficient of each fiber group are specified. As a result, the torque of each fiber group offset each other, and as a result, the torque of the multi-layer yarn was dramatically reduced, and the present invention was reached.

That is, the present invention has a two-layer structure with a core-sheath cross section, and both the core part and the sheath part are composed of a short fiber group, and the sheath part short fiber group is wound in a direction opposite to the twisting direction of the core part short fiber group. The twisting coefficient Ks of the sheath part short fiber group is 1.30 to 1.80, and the absolute value of the difference between the Ks and the twisting coefficient Kc of the core part short fiber group is 0. A method for producing a multi- layer yarn of 80 or less, wherein a spun yarn and a short fiber bundle are simultaneously supplied to a front roller of a ring spinning machine to produce a multi-layer yarn, comprising a second roller and a front roller. While setting the draft ratio (D) between 0.960 <D <1.000 and supplying the short fiber bundle to the front roller, the spun yarn having a twist coefficient of 2.50 to 4.00 is the same front roller. And then spinning the two on the front roller. Method for producing a multi-layer yarn, characterized in that the twisting in the range of twist coefficient 2.30 to 3.00 in a direction opposite that in which the gist of the.

  Since the multilayer yarn of the present invention has a small torque, it can stabilize the form of the woven or knitted fabric and improve the quality. Further, the multi-layer yarn of the present invention is excellent in covering properties, and it is difficult to cause defects such as irritating feeling and wrinkle feeling in the woven or knitted fabric. Furthermore, a woven or knitted fabric with high flexibility can be obtained using the multilayer yarn of the present invention.

  According to the production method of the present invention, it is possible to stably obtain a multi-layer yarn having a small torque and excellent coverage.

  Hereinafter, the present invention will be described in detail.

  The multi-layer yarn of the present invention has a two-layer structure with a core-sheath cross section, and both the core and the sheath are composed of a short fiber group. The term “short fiber” as used herein refers to a short fiber (staple) that is not a continuous fiber.

  Examples of such short fibers include natural fibers such as cotton, wool, hemp, and bamboo, synthetic fibers such as polyester, polylactic acid, polyamide, polyolefin, and polyacrylonitrile, recycled fibers such as viscose rayon and solvent-spun cellulose fibers, Examples thereof include semisynthetic fibers such as acetate and triacetate. In the present invention, these are used singly or as a mixture, and among these, cotton, solvent-spun cellulose fiber, and wool are preferably used. The single yarn fineness and fiber length of the short fiber are not particularly limited, but in the case of cotton and solvent-spun cellulose fiber, the single yarn fineness is 0.6 to 4.2 dtex. The fiber length is preferably 10 to 50 mm, and in the case of wool, the average diameter of short fibers is preferably 15 to 30 μm, and the fiber length is preferably 64 to 102 mm.

  In the present invention, the short fibers to be arranged in the core part and the sheath part may be the same or different, and may be appropriately selected according to the application. Specifically, when making both short fibers different, use of fibers having different raw materials, use of fibers having the same raw materials but different characteristics, and the like can be mentioned.

  In the multi-layer yarn of the present invention, the sheath short fiber group needs to be wound in a direction opposite to the twisting direction of the core short fiber group. If the winding direction of the sheath part is the same as that of the core part, the torque between the fiber groups cannot be offset.

  The mass ratio of each short fiber group is not particularly limited, and may be appropriately set depending on the application.

  Furthermore, the twist coefficient Ks of the sheath portion short fiber group in the multi-layer yarn of the present invention needs to be 1.30 to 1.80. When the twisting coefficient Ks is less than 1.30, the binding force is insufficient, and there is a tendency to generate a large amount of cutting of the sheath fiber group and fluffing during spinning or weaving. On the other hand, when it exceeds 1.80, it becomes difficult to obtain a woven or knitted fabric with high flexibility.

  The twisting coefficient is a numerical value representing the strength of twisting while associating the thickness of the yarn and the number of twists, and the twisting coefficient Ks of the sheath short fiber group is calculated by the following formula (1).

  In the multi-layer yarn of the present invention, the absolute value of the difference between the twist coefficient Ks of the sheath part short fiber group and the twist coefficient Kc of the core part short fiber group needs to be 0.80 or less. Thereby, the torque in the core short fiber group and the sheath short fiber group cancel each other, and as a result, the torque of the multi-layer yarn is greatly reduced.

  In general, the strength of torque depends largely on the twist coefficient, but also depends on the raw material, shape, single yarn fineness, fiber length, thermal history, and the like of the short fiber. The present inventors have found that the reason is not clear, but if the difference in the twisting coefficient of each short fiber group is within the above specific range, any requirement other than the twisting coefficient is complicated. The torque of the multilayer yarn can be reduced.

  In addition, the twist coefficient Kc of the core short fiber group is calculated by the following formula (2).

  The multi-layer yarn of the present invention is basically preferably used as a single yarn, but may be a double yarn if necessary.

  Here, the appearance of the multi-layer yarn of the present invention will be described. The double-layer yarn of the present invention, a single covered yarn obtained using a covering machine, a double-layer yarn obtained by spinning a composite roving having a core-sheath structure, and two rovings are simultaneously spun. When compared with a conventionally known yarn such as the obtained multilayer yarn, the former (multilayer yarn of the present invention) and the latter (conventional known yarn) are common in that they have a core-sheath type two-layer structure. However, the structural features are clearly different. That is, in the former, the sheath short fibers are in a state where the short fibers in the sheath short fibers are scattered, that is, as if the short fibers are uniformly stacked around the core short fibers. While the group is wound, the latter is strong in twisting of the sheath part short fiber group itself, and the short fibers converge. In other words, the former has a very small portion of the core short fiber group exposed on the surface of the yarn, whereas the latter has a core from the gap of the sheath spirally wound around the core short fiber group. The short fiber group is exposed.

  As described above, the multi-layer yarn of the present invention and the conventionally known yarn have completely different appearances.

  The multi-layer yarn of the present invention is excellent in covering property and looks very similar to a spun yarn consisting only of short fibers arranged in the core portion. The knitted or knitted fabric using the multi-layer yarn of the present invention is less likely to cause defects such as irritation and wrinkle even when dyed. The use of the woven and knitted fabrics is wide-ranging, and specific examples include underwear, baby clothes, women's clothes, sportswear, casual wear, work clothes, office clothes, school clothes, business apron, bedding and the like.

  Next, the manufacturing method of the multilayer yarn of this invention is demonstrated.

  In the method for producing a multi-layer yarn of the present invention (hereinafter referred to as “the production method of the present invention”), first, a spun yarn and a coarse yarn obtained by a known method are prepared. Of these, the spun yarn is for forming the core of the multi-layer yarn. As a matter of course, the spun yarn is twisted, and the twist coefficient is preferably 2.50 to 4.00.

  On the other hand, the roving is for forming a sheath.

  Of the two yarns prepared, first, the roving yarn is introduced into a spinning machine to form a short fiber bundle. Next, the short fiber bundle is supplied to the front roller while the draft ratio between the second roller and the front roller is within a specific range, and at the same time, the spun yarn is supplied to the same front roller, and the two are overlapped. And the multilayer yarn of the present invention can be obtained by twisting in the opposite direction to the spun yarn. The “short fiber bundle” refers to an aggregate in which a plurality of short fibers are arranged in a substantially constant direction to form a belt shape.

  The production method of the present invention will be described more specifically with reference to the drawings.

  FIG. 1 is a schematic explanatory view showing one embodiment of the production method of the present invention.

  The roving 1 supplied to the ring spinning machine shown in FIG. 1 is drafted through back rollers 2, 2 ′, aprons 3, 3 ′ and second rollers 4, 4 ′ to form a short fiber bundle 8. The draft ratio (D) between the second roller and the front roller is set to 0.960 <D <1.000 in order to supply the short fiber bundle 8 to the front rollers 5, 5 ′ in a relaxed state. Is preferred. Thereby, the yarn path of the short fiber bundle is swung left and right, and at the same time, the short fiber bundle is opened. As a result, the short fibers are wound around the spun yarn as if they are uniformly stacked one by one, and the coverage of the multi-layer yarn is greatly improved.

  Here, the draft ratio (D) between the second roller and the front roller indicates a so-called mechanical draft, and is calculated by the following equation (3).

  When the draft ratio is 0.960 or less, the yarn path of the short fiber bundle is swung too much to the left and right, and the coating of the core portion is uneven. In some cases, the spun yarn and the short fiber bundle are overlapped. Can not be. On the other hand, when it is 1.000 or more, since the short fiber bundle is stretched without being loosened, the entanglement between the spun yarn and the short fiber bundle tends not to be promoted. In consideration of the degree of entanglement between the spun yarn and the short fiber bundle, the upper limit of the draft ratio is preferably 0.990.

  On the other hand, the spun yarn 6 is supplied to the front rollers 5, 5 'via the press rollers 7, 7'. The supply tension of the spun yarn 6 is not particularly limited as long as the yarn path can be formed. However, if the tension is set too low, the core portion and the sheath portion may be reversed or may have a twisted shape, which is not preferable. On the other hand, if it is too high, the thread may break.

  Thereafter, the front rollers 5 and 5 'are overlapped with each other so that the spun yarn 6 is arranged on the inner side and the short fiber bundle 8 is arranged on the outer side. When the spun yarn 6 and the short fiber bundle 8 are overlapped, no special thing is necessary, and the short fiber bundle 8 is in a relaxed state, whereas the spun yarn 6 is in a stretched state, so that the core is inevitably cored. The spun yarn 6 is arranged in the part, and the short fiber bundle 8 is arranged in the sheath part.

  After the spun yarn 6 and the short fiber bundle 8 are superposed, the snell wire guide 9 is passed through and twisted by the spindle 11 and the ring traveler 10 to obtain the multilayer yarn 12 of the present invention. However, this twisting must be performed in the direction opposite to the spun yarn 6 as the twisting direction. If it goes to the same direction, the twist direction of both short fiber groups of a core part and a sheath part will become the same, and the torque of a multilayer yarn will increase. As this twisting, it is preferable that the twist coefficient α calculated by the following formula (4) is 2.30 to 3.00.

  In the above formula (4), the twist number T is substantially equal to Ts because it corresponds to the twist number when the spun yarn 6 and the short fiber bundle 8 are twisted, that is, the upper twist number. The thickness N is substantially equal to the sum of Ss and Sc (N = 1 / (1 / Ss + 1 / Sc)).

  Since the obtained multi-layered yarn is usually wound up as a fine spinning tube yarn, it is preferable to put it into a finishing process to make cheese.

Next, the present invention will be described specifically by way of examples. The properties of the multi-layer yarns in Examples and Comparative Examples were evaluated by the following methods.
(1) Average single yarn tensile strength and average elongation rate Based on JIS L1095 9.5.1, single yarn tensile strength and elongation rate were measured at a grip interval of 25 cm and a tensile speed of 30 cm / min. The number of tests was 60, and the average values were the average single yarn tensile strength and average elongation.
(2) Minimum 5 tensions Among the single yarn tensile strengths measured in (1) above, the average value from the lowest value to 5 was defined as the minimum 5 tensions.

Example 1
As the roving yarn 1, 160 gr / 30 yd of a cotton roving made of short cotton fibers having a single yarn fineness of 1.15 dtex is supplied to the ring spinning machine shown in FIG. 1, and the roving yarn 1 is fed to the back roller 2, 2 'apron 3, 3'. Then, after drafting 50.4 times into the short fiber bundle 8 through the second rollers 4 and 4 ', the short fiber bundle 8 was supplied to the front rollers 5 and 5' in a relaxed state. The surface speed of the second rollers 4, 4 'is 15.95 m / min, and the draft speed between the second rollers 4, 4' and the front rollers 5, 5 'is 0 for the surface speed of the front rollers 5, 5'. It was set to 15.63 m / min to be .980.

  On the other hand, the spun yarn 6 is made of cotton short fiber having a single yarn fineness of 1.15 dtex, and the 40th cotton spun yarn having a twist direction of S direction and a twisting coefficient of 3.60 is passed through the press rollers 7 and 7 'to the front. Feeded to rollers 5, 5 '. Then, after the spun yarn 6 and the short fiber bundle 8 are superposed on the front roller, at a spindle rotation speed of 8000 rpm, the twist direction Z direction, the twist number 13.0 times / 2.54 cm (twist coefficient 2.55) Was twisted to obtain a double layer yarn 12 of the present invention of 26th (English cotton count).

  In addition, the mass ratio of the short fiber group of the core part and the sheath part in this multi-layered yarn was core part / sheath part = 65/35.

(Comparative Example 1)
By changing the spindle rotation speed to 8000 rpm and 6150 rpm, the twist number in twisting after superposing the spun yarn and the short fiber bundle is changed to 13.0 times / 2.54 cm and changed to 10.0 times / 2. A multilayer yarn was obtained in the same manner as in Example 1 except that the thickness was .54 cm (twist coefficient 1.96).

(Comparative Example 2)
By changing the spindle rotation speed to 8000 rpm and 11700 rpm, the number of twists in twisting after superposing the spun yarn and the short fiber bundle is changed to 13.0 times / 2.54 cm and 19.0 times / 2. A multi-layer yarn was obtained in the same manner as in Example 1 except that the thickness was .54 cm (twist coefficient 3.73).

(Comparative Example 3)
A multi-layer yarn was obtained in the same manner as in Example 1 except that the twist coefficient of the spun yarn was changed to 3.6 and changed to 4.5.

  Table 1 below shows the strength and twist characteristics of the multilayer yarns obtained in the above Examples and Comparative Examples.

  Further, using a cylindrical knitting machine having a needle density of 28 / 2.54 cm, each knitted fabric was produced using each of the multi-layer yarns obtained in the above Examples and Comparative Examples, and after relaxing for 30 minutes with boiling water Directly dyed in a bath containing the dye. Then, the obtained dyed knitted fabric was subjected to a sensory test to evaluate the coverage of each multilayer yarn and the influence on the texture and quality of the multilayer yarn on the fabric.

  As a result, in Example 1, the texture of the knitted fabric is rich in flexibility, and the surface of the knitted fabric is free from defects such as irritation, curling, skewing, and weft, and the multi-layer yarn is coated. It was excellent in properties and could have a positive effect on the texture and quality of the knitted fabric.

  On the other hand, in Comparative Example 1, although the coverage of the multi-layer yarn was good, the tensile strength of the multi-layer yarn was lowered because the twist coefficient Ks of the sheath short fiber group was too low. For this reason, yarn breakage occurred during knitting, and efficient knitting could not be performed. Further, the difference between the twist coefficients Ks and Kc was large, and skew was observed on the surface of the knitted fabric. Even in Comparative Example 2, the coverage of the multi-layer yarn was good. However, since the twist coefficient Ks in the multi-layer yarn is too high, the texture of the knitted fabric is lacking in flexibility, and further, the difference between the twist coefficients Ks and Kc is too large, so that the knitted fabric surface is skewed. Curling was allowed. Even in Comparative Example 3, the coverage of the multi-layer yarn was good. However, the difference between the twist coefficients Ks and Kc was large, and skew was observed on the surface of the knitted fabric.

It is a schematic explanatory drawing which shows one embodiment of the manufacturing method of the multilayer yarn of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Coarse yarn 2, 2 'Back roller 3, 3' Apron 4, 4 'Second roller 5, 5' Front roller 6 Spinning yarn 7, 7 'Press roller 8 Short fiber bundle 9 Snell wire guide 10 Ring traveler 11 Spindle 12 Duplex Layered yarn

Claims (1)

A multi-layered yarn in which the cross-section has a core-sheath type two-layer structure, the core part and the sheath part are both short fiber groups, and the sheath short fiber groups are wound in the opposite direction to the twist direction of the core short fiber groups. The sheath portion short fiber group has a twist coefficient Ks of 1.30 to 1.80, and the absolute value of the difference between the Ks and the core portion short fiber group twist coefficient Kc is 0.80 or less. In the method for producing a multilayer yarn, a spun yarn and a short fiber bundle are simultaneously supplied to a front roller of a ring spinning machine to produce a multilayer yarn, and a draft ratio (D between the second roller and the front roller (D ) 0.960 <set to D <1.000 wherein while supplying the short fiber bundle to the front roller, the twist coefficient is supplied spun yarn from 2.50 to 4.00 to the same front roller, the front roller after superposition of both in, twisting the spun yarn and a reverse coefficient 2 Method for producing a multi-layer yarn, characterized in that the twisting in the range of from 30 to 3.00.