JP2006161227A - Long/short composite spun yarn and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide long/short composite spun yarn of high cohesive force even under hard twist, and to provide a method for stably producing the composite spun yarn. <P>SOLUTION: The long/short composite spun yarn comprises multifilaments as the core and staple fibers as the sheath. The composite spun yarn has a twist multiplier of 3.5-4.5 and a cohesive force frequency of 250-450. The method for producing the long/short composite spun yarn by feeding a common front roller with the multifilaments and staple fiber bundles by a ring spinning frame comprises setting the draft ratio(D) between the front roller and a second roller so as to meet the relationship:0.96≤D<1.00, feeding the staple fiber bundles to the front roller to superimpose both the staple fiber bundles and the multifilaments on each other followed by twisting them together with a twist multiplier of 3.5-4.5. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a long / short composite spun yarn and a method for producing the same.

  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 satisfied under certain conditions, the properties are often disadvantageous under other conditions. For this purpose, these fibers are combined, woven or blended as necessary to compensate for the disadvantages of the characteristics and to be used for a desired application.

  One example is long and short composite spun yarns obtained by spinning and twisting short fibers such as cotton, wool and synthetic short fibers and synthetic multifilaments in the spinning process, which is the final step of the spinning process. Various manufacturing methods are known.

  For example, as a long-standing technique, when a multifilament is mixed and spun with a spinning fiber, a tension fluctuation device is provided in the multifilament supply passage, and a core yarn that is twisted and spun while changing the tension of the multifilament. A manufacturing method is known (see, for example, Patent Document 1). According to this method, the multifilament is partially opened just before being nipped by the front roller, the spinning fiber enters the opening, and the entanglement between the multifilament and the spinning fiber bundle is promoted. A core yarn having an excellent frictional resistance can be obtained.

However, in this method, since the tension of the multifilament fluctuates, there is a problem that spots are easily generated in the covering state of the core yarn. Therefore, by setting the yarn feeding tension to the front roller of the multifilament as a specific condition and uniforming the stress relaxation near the front roller exit of the multifilament, a long and short composite spun yarn with no unevenness in the covering state can be obtained. A method of obtaining is proposed (see, for example, Patent Document 2).
Japanese Patent Publication No. 40-8743 Japanese Patent Laid-Open No. 10-195721

  However, the above-mentioned long / short composite spun yarn is obtained by twisting with a ring spinning machine immediately after being spun from the front roller in a state where the multifilament and the short fiber bundle are overlapped in parallel. For this reason, in this long and short composite spun yarn, there is a problem that the multifilament and the short fiber group are easily separated, and the short fiber is easily cut by an external force such as friction, twisting, etc. received during spinning finishing and / or weaving. . In order to solve this problem, it is generally sufficient to increase the conjugation force of the long / short composite spun yarn. Since the conjugation force of the above-mentioned long and short composite spun yarn is determined only by the strength of twisting, the problem can be easily solved as long as twisting is strengthened, that is, strong twisting is applied. However, when a strong twist is applied, a new problem arises that the texture of the woven or knitted fabric becomes hard.

  The present invention solves such problems, and provides a long / short composite spun yarn excellent in conjugation force without being subjected to strong twisting, and a method for stably producing the long / short composite spun yarn. It is the purpose.

  As a result of intensive studies to solve the above-mentioned problems, the present inventor has obtained a long and short composite spun yarn excellent in conjugation force without twisting, if twisted in a state where the multifilament and the short fiber bundle are entangled. And the present invention has been achieved.

  That is, the first invention is a long / short composite spun yarn in which multifilaments are arranged in the core portion and short fiber groups are arranged in the sheath portion, and the twist coefficient represented by the following formula (1) is 3.5 to 4 And a short and long composite spun yarn characterized in that the number of conjugation forces is 250 to 450 times.

The second invention is a method for producing a long / short composite spun yarn in which a multifilament is arranged in a core portion and a short fiber group is arranged in a sheath portion, and the multifilament and the short fiber bundle are shared by a ring spinning machine. In a method for producing a long and short composite spun yarn by feeding to a front roller, a draft ratio (D) between the second roller and the front roller is set to 0.96 ≦ D <1.00, and the short fiber bundle is The main point is a method for producing a long and short composite spun yarn, characterized in that after being fed to a roller and superposed on each other, the twist coefficient represented by the following formula (1) is twisted as 3.5 to 4.5. Is.

  Since the long and short composite spun yarn of the present invention has excellent conjugation force, short fibers are difficult to cut even when subjected to external forces such as friction and twist during spinning finishing and / or weaving. Further, since the twist applied to the long and short composite spun yarn of the present invention is not strong twist, a woven or knitted fabric having a soft feeling can be obtained by using the long and short composite spun yarn.

  Furthermore, according to the method for producing a long / short composite spun yarn of the present invention, it is possible to stably obtain a long / short composite spun yarn having an excellent conjugation force without being subjected to strong twisting.

  Hereinafter, the present invention will be described in detail.

  The long and short composite spun yarn of the present invention is a yarn having a core-sheath structure in which a multifilament is arranged in a core part and a short fiber group is arranged in a sheath part.

  The multifilament used in the present invention is, for example, a thermoplastic synthetic fiber such as aromatic polyester, aliphatic polyester, polyamide, polyolefin, polyacrylonitrile, filament of chemical fiber such as viscose rayon, solvent-spun cellulose fiber, acetate, etc. Yes, various forms such as untwisted, twisted, or processed yarn can be used. The single filament fineness, the number of filaments, etc. of the multifilament can be appropriately selected depending on the use of the long / short composite spun yarn.

  On the other hand, the short fiber group includes, for example, natural fibers such as cotton and wool, or chemical / synthetic fibers such as aromatic polyester, aliphatic polyester, polyamide, polyolefin, polyacrylonitrile, viscose rayon, solvent-spun cellulose fiber, and acetate. There are no particular limitations on the single yarn fineness and fiber length.

  The long and short composite spun yarn of the present invention is required to have a twist coefficient of 3.5 to 4.5 represented by the following formula (1), and preferably 3.8 to 4.2.

When the twist coefficient is less than 3.5, not only the short fibers are removed and the weaving and knitting properties are hindered, but also the knitting results in pilling and the quality is impaired. On the other hand, if it exceeds 4.5, the long and short composite spun yarn becomes too dense, and the texture of the woven or knitted fabric becomes hard.

  Further, the long and short composite spun yarn of the present invention needs to have a conjugation force number of 250 to 450 times, preferably 300 to 400 times. The number of conjugation forces is an index that quantitatively represents the conjugation force of long and short composite spun yarns. Specifically, the number of times of conjugation force referred to in the present invention is measured by the following method using a conjugation force tester, and is the friction until the short filament group is cut and the multifilament at the core is exposed. It is the number of times. That is, a long and short composite spun yarn was set on a warp conjugation force tester (manufactured by Iwata Riken Co., Ltd., model number: INSERT No0072) according to the case of the spun yarn test, the rotational speed of the friction plate was 100 rpm, and the load was 50 g. The number of times that the short fiber group of the long and short composite spun yarn sheath part is cut and the multifilament in the same core is exposed is measured for 10 long and short composite spun yarns, and the average value is defined as the number of conjugation forces. .

  The higher the conjugation force, the more closely the multifilament and the short fiber group are in close contact with each other. Therefore, even if the long and short composite spun yarn receives an external force, the short fiber tends to be difficult to cut.

  When the number of conjugation forces is less than 250, the multifilament and the short fiber group are separated, and the short fibers are easily cut by an external force such as friction, twisting, or the like that is received during spinning finishing and / or weaving / knitting. On the other hand, when it exceeds 450 times, the long and short composite spun yarn becomes too dense, and the texture of the woven or knitted fabric becomes hard.

  Next, a method for producing the long and short composite spun yarn of the present invention will be described.

  FIG. 1 is a schematic explanatory view showing one embodiment of a method for producing a long / short composite spun yarn of the present invention.

  The roving yarn 1 supplied to the ring spinning machine shown in FIG. 1 is drafted at a predetermined magnification through back rollers 2, 2 ', aprons 3, 3' and second rollers 4, 4 ' Become. Then, the short fiber bundle 8 is supplied to the front rollers 5, 5 'in a relaxed state.

  On the other hand, the multifilament 6 is supplied to the front rollers 5, 5 'via the press rollers 7, 7'.

  In the front roller, the multifilament 6 and the short fiber bundle 8 are overlapped so that the multifilament 6 is arranged in the core portion and the short fiber bundle 8 is arranged in the sheath portion. That is, while the short fiber bundle 8 is in a relaxed state, since the multifilament 6 is in a stretched state, the multifilament 6 is inevitably disposed in the core portion and the short fiber bundle 8 is disposed in the sheath portion. is there. In addition, it is preferable that the tension | tensile_strength of the multifilament 6 is 0.1-0.2 cN / dtex. If it is less than 0.1 cN / dtex, the multifilament 6 and the short fiber bundle 8 may be twisted or the core portion and the sheath portion may be reversed. On the other hand, if it exceeds 0.2 cN / dtex, the entanglement between the multifilament 6 and the short fiber bundle 8 may be hindered.

  After the multifilament 6 and the short fiber bundle 8 are superposed as described above, the multifilament 6 and the short fiber bundle 8 pass through the snell wire guide 9, and the twist coefficient 3.5 represented by the following formula (1) by the spindle 11 and the ring traveler 10. Twist of -4.5 is given and it becomes the long and short composite spun yarn 12 of this invention.

In the present invention, it is necessary to set the draft ratio (D) between the second roller and the front roller to 0.96 ≦ D <1.00. Thereby, the short fiber bundle is supplied to the front roller in a relaxed state. As a result, the yarn path of the short fiber bundle is swung left and right, and at the same time, the short fiber bundle is opened, and the entanglement between the multifilament and the short fiber bundle is promoted.

  The draft ratio (D) between the second roller and the front roller in the present invention refers to a so-called mechanical draft, and is calculated by the following formula (2).

If the draft ratio is less than 0.96, the yarn path of the short fiber bundle swings too much to the left and right, causing unevenness in the covering state of the long and short composite spun yarn, and in extreme cases, the multifilament and the short fiber bundle It becomes impossible to superimpose. On the other hand, when it is 1.00 or more, the short fiber bundle is stretched without being loosened, and thus the entanglement between the multifilament and the short fiber bundle is not promoted.

  In the present invention, the upper limit of the draft ratio is preferably set to 0.99 in consideration of the covering state and the degree of entanglement.

  In the present invention, twisting is performed in a state where the multifilament and the short fiber bundle are entangled in this way, so that a long and short composite spun yarn excellent in conjugation force can be obtained without applying strong twisting.

  Next, the present invention will be described specifically by way of examples. In addition, the frequency | count of the conjugation force of the long and short composite spun yarn in an Example and a comparative example was measured by the above-mentioned method.

Example 1
A cotton coarse yarn 180 gr / 30 yd as the coarse yarn 1 is supplied to the ring spinning machine shown in FIG. 1, and the coarse yarn 1 is passed through the back rollers 2, 2 ′ apron 3, 3 ′ and second rollers 4, 4 ′. After drafting 6 times to obtain a short fiber bundle 8, the short fiber bundle 8 was supplied to the front rollers 5, 5 'in a relaxed state. The surface speed of the second rollers 4 and 4 ′ is 10.39 m / min, and the surface speed of the front rollers 5 and 5 ′ is 0 when the draft ratio between the second rollers 4 and 4 ′ and the front rollers 5 and 5 ′ is 0. It was set to 10.08 m / min to be .97. On the other hand, nylon 6 multifilament 44dtex / 48f as multifilament 6 was supplied to the same ring spinning machine and supplied to front rollers 5, 5 'via press rollers 7, 7'. Then, after the multifilament 6 and the short fiber bundle 8 are superposed on the front roller, a twist of 3.9 is applied at a spindle rotation speed of 11000 rpm, and the core sheath of 50th (English cotton count) is applied. A long and short composite spun yarn 12 of the present invention having a structure was obtained.

  The number of conjugation forces of the obtained long / short composite spun yarn was measured and found to be 363.7 times.

(Comparative Example 1)
By changing the surface speed of the front rollers 5 and 5 'to 10.39 m / min, the draft ratio between the second rollers 4 and 4' and the front rollers 5 and 5 'was set to 1.00, and twisting A comparative long and short composite spun yarn was obtained in the same manner as in Example 1 except that the spindle speed was changed to 11300 rpm in order to make the coefficient 3.9.

  The number of conjugation forces of the obtained long and short composite spun yarn was measured and found to be 135.9.

(Comparative Example 2)
By changing the surface speed of the front rollers 5 and 5 'to 9.87 m / min, the draft ratio between the second rollers 4 and 4' and the front rollers 5 and 5 'was set to 0.95, and twisting Except that the spindle rotation speed was changed to 10800 rpm in order to make the coefficient 3.9, the same procedure as in Example 1 was performed, and an attempt was made to collect comparatively long and short composite spun yarns. However, since the start of the collection, the yarn path of the short fiber bundle is too large to cause unevenness in the covering state of the long and short composite spun yarn. After a while, the yarn path of the short fiber bundle is detached from the front roller, and the multifilament and the short fiber bundle are short. The collection was stopped because the fiber bundle could not be overlapped.

  As is clear from the above results, the long and short composite spun yarn of the present invention has excellent conjugation force, and can prevent the short fibers from being cut by external forces such as friction and twisting during spinning finishing and / or weaving. It was a thing.

  On the other hand, in Comparative Example 1, although the twisting coefficient was 3.9, which was the same as that in Example 1, the result of poor conjugation force was obtained. This is because the draft ratio between the second roller and the front roller is set to 1.00, so that the short fiber bundle is supplied to the front roller in a stretched state without loosening, and the multifilament and the short fiber bundle are entangled. It is presumed that it was not promoted.

It is a schematic explanatory drawing which shows one embodiment of the manufacturing method of the long and short composite spun 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 Multifilament 7, 7 'Press roller 8 Short fiber bundle 9 Snell wire guide 10 Ring traveler 11 Spindle 12 Long and short Composite spun yarn

Claims (2)

A long / short composite spun yarn in which a multifilament is arranged in a core part and a short fiber group is arranged in a sheath part, and a twist coefficient represented by the following formula (1) is 3.5 to 4.5, and the number of conjugation times Is a long and short composite spun yarn characterized by having 250 to 450 times.
A method for producing long and short composite spun yarn in which a multifilament is arranged in the core and a short fiber group is arranged in the sheath, and the multifilament and the short fiber bundle are supplied to a common front roller by a ring spinning machine. In the method of manufacturing a composite spun yarn, the draft ratio (D) between the second roller and the front roller is set to 0.96 ≦ D <1.00, and the short fiber bundle is supplied to the front roller to overlap the two. After combining, the method of producing a long / short composite spun yarn is characterized by twisting the twist coefficient represented by the following formula (1) as 3.5 to 4.5.