JPH0784683B2 - Method for producing polyamide false twist textured yarn - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for producing a false-twisted polyamide yarn suitable for a woven or knitted fabric having a natural and fine bulging feeling and a good soft feeling.

2. Description of the Related Art Conventionally, in order to obtain a yarn used for a woven or knitted product having a swelling feeling, a method of giving a swelling feeling by relaxing heat treatment of a mixed yarn composed of two or more kinds of multifilaments having different heat shrinkage rates is known. However, the yarn obtained by this method has a drawback that it lacks in softness. In order to eliminate such a defect, a method of false-twisting a mixed filament yarn composed of two or more kinds of multifilaments having different heat shrinkage rates is known.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention In a method for obtaining a yarn suitable for a woven or knitted fabric having a feeling of swelling, a conventionally known mixed yarn composed of two or more kinds of multifilaments having different heat shrinkages is false twisted. In this method, the morphology of the mixed yarn before the false twisting process is uniform, and the difference in the heat shrinkage rate between the two or more multifilaments is small due to the heat received by the heat setting during the false twisting process, so it is natural and fine. There is a drawback that it is difficult to obtain a false twisted textured yarn having a swelling feeling.

The present invention is based on the finding that the above-mentioned drawbacks can be solved by false twisting a mixed yarn made of a specific polyamide multifilament and having an appropriate loop, based on the finding that a natural fine swelling and good softness are achieved. An object of the present invention is to provide a method for producing a false-twisted polyamide yarn, which is suitable for obtaining a woven or knitted fabric having a feeling.

Means for Solving the Problems In the method for producing a false-twisted polyamide yarn of the present invention, the natural shrinkage is 2.8% or less and the difference in the natural shrinkage is 0.8% or more.
A mixed yarn composed of more than one kind of polyamide multifilament and having 3 or more open loops per 10 cm has a twist angle calculated from the following formula of 43 at a temperature lower than the fusion temperature.
It is characterized in that false twisting is performed under the condition of ° to 50 °.

However, θ: twist angle D: fineness of multifilament (denier) T: false twist number of twists (times / m) First, in the present invention, the mixed yarns used for false twisting are two or more kinds having different natural shrinkage rates. It is required that the natural shrinkage rate of each polyamide multifilament is 2.8% or less. When the natural shrinkage ratio exceeds 2.8%, the yarn quality is likely to change with time, and the yarn quality becomes unstable when the yarn layer is strongly tightened, particularly in a package state such as a pan, which is not preferable.

Next, the difference in natural shrinkage between the above-mentioned two or more polyamide multifilaments must be 0.8% or more. If the difference in natural shrinkage is less than 0.8%, the number of open fiber loops that appear when the yarn is unwound from the package is small, and the false twisted yarn has a fine swelling feeling as described later. It is not preferable because it is difficult to form three or more open fiber loops per 10 cm required for the above.

The natural shrinkage ratio is calculated by the following formula, and is shown as an average value of 5 tests.

However, l ₀ : JIS L 1013 Hot water shrinkage ratio Sampled by the same method as A method, and measured ridge length (mm) l: l _{0 The} ridge was left for 120 hours under no load and then l ₀ The length of the ridge (mm) measured under the same load as that of the measurement was one example of a combination of two types of polyamide multifilaments satisfying the above-mentioned conditions, nylon 6 multifilament produced by high-speed spinning, ordinary spinning and drawing. The combination with Nylon 6 multifilament by the two-step method is mentioned. That is, when nylon 6 is spun at a high speed of about 4000 m / min, a natural shrinkage ratio of 1.2% or less can be easily obtained, while an undrawn yarn obtained by spinning nylon 6 at a spinning speed of about 1000 to 1800 m / min is used. If stretched by a conventional method, it is possible to easily obtain a material having a natural shrinkage rate of 2% or more, and it is possible to use a material that is industrially produced in large quantities as it is. Further, the above-mentioned two or more types of polyamide multifilament mixing treatment is performed by a conventionally known fluid ejection treatment device.
It is sufficient to entangle mixed fibers simultaneously. If there is a difference in natural shrinkage between the two types of yarns that make up the obtained mixed fiber,
As shown in the figure, the yarn 1 having a large natural shrinkage ratio forms a core portion, and the yarn 2 having a small natural shrinkage ratio forms a floating portion in a loop shape, and when unwound, an open fiber loop is developed. The number of manifestations can be adjusted by appropriately selecting the natural shrinkage ratios of the two types of yarns constituting the mixed fiber.

As described above, the number of open fiber loops that appear when the mixed fiber is unwound must be 3 or more per 10 cm,
If the number of open fiber loops is less than 3 per 10 cm, it is difficult to obtain a yarn that forms a woven or knitted fabric having a natural, fine bulging feeling and a good soft feeling.

The method for measuring the number of opened fiber-like loops is as follows. First, by the same method as JIS L 1013 hot water shrinkage A method,
After collecting the threads of the mixed fiber, leave it for 24 hours with no load and in a horizontal state, remove one thread randomly from 20 times of winding and strain it with a load of 10 mg / d, and then with the naked eye. The number of open fiber loops is measured with a length of 20 cm and the number of tests is 5 and the average value is taken as the number of open fiber loops.

Next, false twisting is applied to the mixed fiber. The false twisting process needs to be performed at a temperature lower than the fusion temperature of the polyamide multifilament, and if the false twisting process is performed at a temperature higher than the fusion temperature, it becomes a fused yarn or a partially fused yarn, which is a natural fine bulge. It is difficult to obtain a false twisted textured yarn. It is also necessary to perform false twisting under the condition that the twist angle is 43 ° to 50 °. If the twist angle is less than 43 °, a false twisted yarn having sufficient crimp cannot be obtained.
If it exceeds 0, double twisting phenomenon is likely to occur and yarn breakage easily occurs, and it is difficult to obtain a false twist textured yarn having uniform dyeability, which is not preferable. The twist angle is preferably 44 ° to 48 ° in order to obtain a false twisted yarn which can form a woven or knitted fabric having an excellent natural and fine bulging and soft feeling. The obtained false twisted yarn has a form in which the low crimp portion A and the high crimp portion B are mixed, as shown in FIG.

Action Natural shrinkage is 2.8% or less, the difference is 0.8% or more, two or more polyamide multifilaments are combined, entangled by fluid treatment, etc., and wound into a package such as a pan, and then naturally shrink when unwound. The polyamide multifilament having a high rate is strained, and the polyamide multifilament having a low natural shrinkage is relaxed to become a mixed fiber in which an open loop is expressed. By false twisting this mixed fiber,
The polyamide multifilament with a large natural shrinkage is heat set under high tension to be a high crimp, and the polyamide multifilament with a small natural shrinkage is heat set under a low tension to be a low crimp, resulting in a natural and fine crimp. A yarn capable of forming a woven or knitted product having a feeling of swelling is obtained.

Example Nylon 6 having an intrinsic viscosity [η] = 1.0 was spun at a spinning temperature of 280 ° C. and the number of holes was determined by a conventional two-step method of spinning and drawing nylon 6.
Using 12 spinnerets, melt-spun at a spinning speed of 1200 m / min, drawn at a draw ratio of 3.27, a draw speed of 950 m / min, brand 30d / 12f,
Polyamide multifilament 1 having a fineness of 29.6d, an elongation of 40% and a natural shrinkage of 2.4% was obtained.

On the other hand, nylon 6 with an intrinsic viscosity [η] = 1.0 is used at a spinning temperature of 280
Melt-spun using a spinneret with 34 holes at ℃ and wound at 4000 m / min, brand 40d / 34F, fineness 39.5d, elongation 66%, natural shrinkage
0.9% of polyamide multifilament 2 was obtained.

The above-mentioned two types of polyamide multifilaments 1 and 2
Are aligned, and a tension of 0.4 g / d is applied to the total fineness to form one bundled yarn, which is then mixed by air injection and the speed is 600 m /
In minutes, it was wound up in a pan to obtain a mixed yarn. The mixed filament yarn when unwinding the pan has a form as shown in Fig. 1 and expresses a portion in which the polyamide multifilament 2 floats in a loop, that is, an open loop, the number of which is 3.7 per 10 cm. Met.

Next, using a LS-6 type false twisting machine, the mixed fiber was rotated at a spindle speed of 40 × 10 ⁴ rpm, a twist angle of 47.0 °, and a false twist number of 3668.
False twisting was performed under the conditions of a twist / m, false twisting direction Z, and a heater temperature of 180 ° and an overfeed rate of −8.6% / 6.2%. The obtained false twisted yarn has a fineness of 65.8d, a strength of 3.93g / d and an elongation of 30.8%.
In the form as shown in the figure, the polyamide multifilament 1 having a large natural shrinkage occupies the core part as the high crimp portion A, and the polyamide multifilament 2 having a small natural shrinkage becomes the low crimp B to form a loop. The yarn was opened and had a bulge and softness.

When a plain weave fabric was woven using the above false twisted yarn by a conventional method, a fabric having a natural bulging feeling and a good soft feeling was obtained.

Comparative Example 1 Nylon 6 having an intrinsic viscosity [η] = 1.0 was spun at a spinning temperature of 280 ° C. and the number of holes was 34 by the two-step method of spinning and drawing in the same manner as in the example.
Melt spinning at a spinning speed of 1200 m / min, and stretching at a draw ratio of 3.0 and a drawing speed of 950 m / min.
A polyamide multifilament 3 having f, fineness of 39.1d, elongation of 52% and natural shrinkage of 1.8% was obtained. This natural shrinkage rate is 1.8%
The polyamide multifilament 3 in Example 1 and the polyamide multifilament 1 having a natural shrinkage ratio of 2.4% obtained in Example were aligned, and a mixed fiber was prepared under the same conditions as in Example. When the obtained mixed fiber was unwound from the pan, the number of open loops that appeared was only 2.2 per 10 cm. The mixed yarn was subjected to false twisting under exactly the same conditions as in Example, but no yarn capable of forming a woven or knitted fabric having a natural bulge and a soft feeling was obtained.

Comparative Example 2 Nylon 6 having an intrinsic viscosity [η] = 1.0 was melt-spun at a spinning speed of 1200 m / min using a spinneret having a spinning temperature of 280 ° C. and a hole number of 12 by the two-step method of spinning and drawing in the same manner as in Example. And draw at a draw ratio of 3.51 and a draw speed of 950 m / min.
A polyamide multifilament 4 having f, fineness of 28.2d, elongation of 33% and natural shrinkage of 2.9% was obtained. This natural shrinkage rate is 2.9%
The polyamide multifilament 4 of Example 1 and the polyamide multifilament 2 having a natural shrinkage of 0.9% obtained in Example were aligned, and a mixed fiber was prepared under the same conditions as in Example. The number of open loops that appeared when the obtained mixed yarn was unwound from the pan was 4.4 per 10 cm, and there were three or more, but the polyamide multifilament 4 with a natural shrinkage of 2.9% changed with time. , Especially in the part corresponding to the pan taper part, the shape of the open fiber loop that appears during unwinding greatly changes from the other parts, and even if false twisting is performed under the same conditions as in the example, the appearance cycle Abnormalities were observed, and when it was made into a woven or knitted product, it might appear as a defect, and it was not qualified.

EFFECTS OF THE INVENTION By knitting and weaving using the false-twisted polyamide yarn obtained in the present invention, it is possible to obtain a knitted fabric and a woven fabric having a natural and fine swelling feeling and a good soft feeling.

[Brief description of drawings]

FIG. 1 is a schematic view of the appearance of the mixed yarn in the present invention at the time of unwinding, and FIG. 2 is a schematic view of the appearance of the false-twisted polyamide yarn obtained in the present invention. 1 ... High natural shrinkage polyamide multifilament, 2
...... Low natural shrinkage polyamide multifilament

Claims (1)

[Claims] 1. A mixture comprising two or more polyamide multifilaments having a natural shrinkage of 2.8% or less and a natural shrinkage difference of 0.8% or more, and having an open loop number of 3 or more per 10 cm. A method for producing a false-twisted polyamide yarn, wherein the false-twisted yarn is subjected to false twisting at a temperature lower than the fusing temperature under the condition that the twist angle calculated from the following formula is 43 ° to 50 °. However, θ: twist angle D: fineness of multifilament (denier) T: false twist number (times / m)