JP4383955B2 - Polyamide extra fine fiber for false twist - Google Patents

Description

  The present invention relates to an extra fine polyamide fiber having a single yarn fineness of 1.2 dtex or less, and relates to a false twist polyamide extra fine fiber capable of obtaining a false twist crimped yarn excellent in softness by performing false twisting. It is.

  Conventionally, it has been practiced to obtain a false twisted crimped yarn having a soft texture and stretchability by subjecting a polyamide fiber to false twisting at high speed and imparting crimp (see, for example, Patent Document 1). When such false twisted crimped yarn is used, a soft and stretchable fabric can be obtained.

  Polyamide fibers used for the false twisting are generally those having a single yarn fineness of 1.8 to 3.8 dtex and a friction coefficient of 0.2 to 0.3. In other words, when the false twisting process is performed, if there is not a certain amount of friction, the false twisting process does not take a twist and the crimped yarn cannot be used. It was. This phenomenon was particularly remarkable when false twisting was performed at high speed.

  In order to obtain a polyamide fiber having a certain degree of friction coefficient, generally, a method of applying a spinning oil is adopted, but according to this method, a polyamide fiber having a fineness and a high friction coefficient is used. It was difficult to get. That is, when an ultrafine fiber is spun and an oil agent is applied, the friction coefficient becomes high and resistance is applied when the oil agent is applied. There was a problem of cutting.

  For this reason, a polyamide fiber for false twisting which is an ultrafine fiber of 1.2 dtex or less and has a friction coefficient to some extent has not been proposed.

In addition, if the polyamide fiber has a generally used single fiber fineness of about 1.8 to 3.8 dtex, the fabric obtained by applying false twisting and knitting or weaving has sufficient elasticity and soft wind. It did not have a combination.
Japanese Examined Patent Publication No. 7-84683

  The present invention solves the problems as described above, can provide sufficient false twist even in false twisting at high speed, has a small single yarn fineness, and is obtained by weaving and weaving. An object of the present invention is to provide a polyamide ultrafine fiber for false twisting that can provide sufficient stretchability and soft texture.

As a result of intensive studies to solve the above-mentioned problems, the present inventors have reached the present invention.
That is, according to the present invention, in a fiber made of a polyamide resin having a single yarn fineness of 1.2 dtex or less, the friction coefficient is 0.3 to 0.4, the elongation is 50 to 63%, and the hot water shrinkage is 10% or less. The gist of the present invention is a polyamide ultrafine fiber for false twisting.

  The polyamide ultrafine fiber of the present invention can provide a sufficient false twist even in false twisting at high speed, and can obtain a false twisted crimped yarn having a small single yarn fineness and excellent in softness. Further, when this false twisted crimped yarn is used, it becomes possible to obtain a woven or knitted fabric having sufficient stretchability and soft texture.

Hereinafter, the present invention will be described in detail.
The polyamide ultrafine fiber of the present invention is a fiber made of a polyamide resin having a single yarn fineness of 1.2 dtex or less and a friction coefficient of 0.3 to 0.4.

The single yarn fineness is a value obtained by dividing the fineness of the yarn by the number of single yarns. The smaller the value, the finer the single yarn, and the fabric obtained by weaving and knitting the false twisted yarn has a soft texture and stretch. Have sex. When the single yarn fineness exceeds 1.2 dtex, the softness of the obtained fabric is inferior and the stretchability is also inferior.
The coefficient of friction is an index of the frictional resistance on the surface of the yarn, and the larger the value, the greater the friction and the less slip. The friction coefficient in the present invention is a yarn / metal dynamic friction coefficient (F / Mμd), and is measured using the measuring apparatus of FIG. The take-up roller 1 causes the yarn to run at 500 m / min, and the entry side tension T1 to the metal friction body 2 is measured by the tension meter 3 and the exit side tension T2 is measured by the tension meter 4. Furthermore, as shown in FIG. 2, the depression angle θ (radian) between the yarn and the metal friction body 2 is measured, and the yarn / metal dynamic friction coefficient (F / Mμd) is calculated from the following equation using Amonton's law.
Amonton's Law T2 = T1e ^μθ
F / Mμd (μ) = (lnT2 / T1) / θ

  In the present invention, in the ultrafine fiber of 1.2 dtex or less as described above, the friction coefficient is set to 0.3 to 0.00 in order to provide sufficient false twist when false twisting is performed at high speed. 4

  When the coefficient of friction is less than 0.3, the false twisting process has little frictional resistance on the surface of the yarn, so that the twisted real twist is not completely untwisted but remains untwisted, The quality of twisted yarn is impaired.

  On the other hand, if the friction coefficient exceeds 0.4, friction resistance is applied at the stage where the oil agent is applied in order to obtain such a friction coefficient, single yarn breakage occurs in the vicinity of the oil agent application device, Fluffing occurs, the process until winding up, and even during false twisting, fuzz frequently occurs due to rubbing with various guides, and the operability is also deteriorated.

  Furthermore, the polyamide ultrafine fiber of the present invention has an elongation of 50 to 63% and a hot water shrinkage of 10% or less. If the elongation is less than 50%, the number of actual twists to be twisted in the false twisting process is reduced, so that sufficient crimps are not imparted to the obtained false twisted yarn. On the other hand, when the elongation exceeds 63%, the actual number of twists to be twisted becomes excessive, and the false twisted yarn obtained has fluff and the strength is lowered.

  Further, if the hot water shrinkage rate exceeds 10%, when heat is applied during false twisting, the texture becomes a hard false twisted yarn, and even if no heat is applied during false twist, The texture of the fabric obtained by weaving and dyeing is hardened.

  Examples of the polyamide resin that forms the polyamide ultrafine fiber of the present invention include nylon 6, nylon 11, nylon 12, nylon 46, nylon 66, nylon 610, and the like, and polyamides containing these as main components. Copolymerized or blended materials can be used. And, as long as the effect of the present invention is not impaired, various additives, ultraviolet absorbers, matting agents, modifiers, antistatic agents, pigments, silicon dioxide, etc. are added to the thermoplastic polyamide resin. Also good.

Next, the manufacturing method of the polyamide extra fine fiber of this invention is demonstrated.
First, the yarn spun from the spinneret of the melt spinning apparatus is cooled by blowing cooling air, and a spinning oil is applied and converged. The friction coefficient is adjusted by adding a spinning oil. Normally, as described above, if an oil that increases the friction coefficient is applied to an ultrafine fiber having a single yarn fineness of 1.2 dtex or less, yarn breakage occurs and winding is performed. It was difficult. In the present invention, the position where the oil agent is applied is made lower than usual, and by adjusting the cooling temperature, the type of the spinning oil, etc., the single yarn breakage at the spinning oil application position is reduced so that it can be converged well. And can be wound up.

  The yarns thus converged are taken up by the first godet roller, drawn between the second godet roller, and taken up by a winder. At this time, it is preferable that 2700 <S / D <5800 is satisfied between the single yarn fineness D (dtex) and the spinning speed S (m / min). When the S / D is less than 2700, the spinning operability is good, but the elongation of the resulting polyamide ultrafine fiber tends to exceed 63%. Also, if the S / D exceeds 5800, the frictional resistance in the spinning process increases, and single yarn breakage tends to occur, fluffing due to single yarn jumping out directly under the nozzle and rubbing with the guide occurs, and operability is improved. It is easy to get worse.

  The stretching condition between the first godet roller and the second godet roller is preferably about 1.01 to 1.15 times. Depending on the type of yarn, the stretching may be either hot stretching or cold stretching at room temperature. In the case of, it is preferable to carry out at about 50-110 degreeC.

Next, the present invention will be specifically described with reference to examples. Various values in the examples were measured and evaluated as follows.
(A) Friction coefficient It measured by the said method.
(B) Strong elongation Measured according to JIS L1090.
(C) Hot water shrinkage rate Measured according to JIS L1013.
(D) Relative viscosity Measured at a concentration of 1 g / dl and a temperature of 25 ° C. using 96% sulfuric acid as a catalyst.
(E) Untwisting at the time of false twisting Using a false twisting machine (HTS-1500) manufactured by Teijin Seiki Co., Ltd. Twist processing was performed. A tricot knitted fabric was knitted with 100 m of the obtained false twisted yarn as a mesh structure, and the number of untwisted yarns was measured and evaluated in the following three stages.
○ ・ ・ ・ 0 pieces △ ・ ・ ・ 1-5 pieces × ・ ・ ・ 6 pieces or more (f) Texture of fabric Using false twisted yarn obtained in the same manner as in (e), a mesh structure and tricot Knitted fabric was knitted. The knitted fabric was dyed and finished in a conventional manner, and the texture of the obtained knitted fabric was evaluated in terms of softness and stretchability by the following three steps in terms of touch.
○ ・ ・ ・ Good △ ・ ・ ・ Slightly bad × ・ ・ ・ Bad

Example 1
Using nylon 6 having a relative viscosity of 2.50, a spinneret was attached to a conventional melt spinning apparatus and melt spinning was performed at a polymer temperature of 255 ° C. The fiber was cooled by blowing cooling air at a temperature of 18 ° C. to give a spinning oil. At this time, a slit-type oil agent applying device was provided at a position 100 cm below from just below the spinneret, and an emulsion oil agent was used as the spinning oil agent, so that the amount of adhesion was 0.65% by mass with respect to the fibers.
Subsequently, it was pulled once on a first godet roller at a speed of 3845 m / min, and then pulled once on a second godet roller at a speed of 3922 m / min, and then picked up at a speed of 4000 m / min. A polyamide ultrafine fiber of 50 dtex / 48f was obtained.

Example 2
In Example 1, the first godet roller was set at a speed of 3980 m / min, the second godet roller was set at a speed of 4039 m / min, and the scraping speed was set at 4100 m / min, and the same as in Example 1 except that a polyamide ultrafine fiber of 78 dtex / 68f was obtained. Went to.

Example 3
Example 1 was the same as Example 1 except that the first godet roller had a speed of 3421 m / min, the second godet roller had a speed of 3558 m / min, and the scraping speed was 3700 m / min to obtain a 44 dtex / 68 f polyamide ultrafine fiber. Went to.

Example 4
In Example 1, the speed was 3514 m / min, pulled on the first godet roller at room temperature three times, and then the speed was 4041 m / min, pulled on the second godet roller at 110 ° C. four times, and then the speed was 3900 m / min. This was carried out in the same manner as in Example 1 except that a polyamide ultrafine fiber of 50 dtex / 48 f was obtained by scraping.

Comparative Example 1
In Example 1, the first godet roller was set at a speed of 3941 m / min, the second godet roller was set at a speed of 4039 m / min, and the scraping speed was set at 4020 m / min, and a polyamide fiber of 90 dtex / 24f was obtained in the same manner as in Example 1. went.

Comparative Example 2
The same operation as in Example 1 was performed except that the oil film strength was changed to be lower than that of the emulsion oil used in Example 1.

Comparative Example 3
In Example 4, the speed was 3564 m / min, pulled on the first godet roller at room temperature three times, and then the speed was 4456 m / min, pulled on the second godet roller at 110 ° C. four times and then pulled at a speed of 3900 m / min. This was carried out in the same manner as in Example 4 except that a polyamide ultrafine fiber of 50 dtex / 48 f was obtained.

Comparative Example 4
Example 1 was the same as Example 1 except that the first godet roller had a speed of 3921 m / min, the second godet roller had a speed of 3960 m / min, and the scraping speed was 4020 m / min, and a 44 dtex / 68f polyamide ultrafine fiber was obtained. Went to.

  Table 1 shows various physical property values and evaluation results of the fibers obtained in Examples 1 to 4 and Comparative Examples 1 to 4.

As is clear from Table 1, the polyamide ultrafine fibers obtained in Examples 1 to 4 were able to be obtained with good operability without occurrence of popping or fluff due to single yarn breakage. Further, the false twisting operability of the obtained polyamide ultrafine fiber was good without untwisting. Furthermore, the texture of the fabric obtained from the false twisted yarn was soft and excellent in stretchability.
On the other hand, the fiber of Comparative Example 1 had good spinning operability and false twist operability, but the fineness of the single yarn fineness was 3.75 dtex, so the texture of the resulting fabric was hard. Since the fiber of Comparative Example 2 had a low coefficient of friction, untwisting occurred during false twisting, false twist operability deteriorated, and the quality of the obtained false twisted yarn was poor. Since the fiber of Comparative Example 3 has a low elongation and a low hot water shrinkage rate, the obtained false twisted yarn was not imparted with sufficient crimp, and the resulting fabric was also hard in texture. . Since the fiber of Comparative Example 4 had an S / D exceeding 5800, single yarn breakage occurred, fluff due to jumping of the single yarn directly under the nozzle and rubbing with the guide occurred, and the spinning operability was poor. . Moreover, it became a fiber with low elongation, and the obtained false twisted yarn was not imparted with sufficient crimp, and the obtained fabric was also hard in texture.

It is a schematic explanatory drawing of the apparatus which measures the friction coefficient in the polyamide ultrafine fiber of this invention. It is a partially expanded view of the metal friction body 2 in FIG.

Claims (1)

A fiber made of a polyamide resin having a single yarn fineness of 1.2 dtex or less has a friction coefficient of 0.3 to 0.4, an elongation of 50 to 63%, and a hot water shrinkage of 10% or less. Polyamide extra fine fiber for false twist.