JPH08260268A - False-twisting method of polyester thick and thin yarn - Google Patents

Abstract

PURPOSE: To obtain a special false twist yarn having unevenness of dyed color tone in the fiber-axis direction and excellent in crimping property by applying a one-step process of drawing and false-twisting on a polyester thick and thin yarn under a special condition. CONSTITUTION: A polyester thick and thin yarn A is taken out through unreeling guides B, C, and it is subjected to a one-step process of drawing and false- twisting between a feeding roll D and the first delivery roll J by means of a non-contact heater E of >=300 deg.C and a friction false-twisting apparatus G under a condition which satisfying the following relations. 1.20+0.9DS×10-2 <=DR<=1.30+0.9DS×10-2 (DR is a draw ratio; DS is a processing speed). Further, a ratio of an average of untwisting tension T2 measured over 20m of a running yarn length with a pitch of 0.5m to its standard deviation, that is, CV% is 5-12% and a ratio of the untwisting tension T2 to twisting tension T1 , that is T2 /T1 , is 0.8-1.2. Furthermore, the processing speed DS is >=500m/min.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for false twisting polyester thick and thin yarns.
The present invention relates to a method for producing a special false twisted yarn having a crimpability which is excellent in crimping property at a high speed by subjecting a polyester thick and thin yarn to a friction false twisting process at the same time as being drawn, which has a difference in color density in the fiber axis direction. .

[0002]

2. Description of the Prior Art Conventionally, when false twisting is performed on a polyester thick and thin yarn in which chic and thin parts are alternately mixed in the fiber axis direction and which has a difference in color density, there is a range of conditions under which stable processing is possible. Narrow, for example, when false-twisting at high speed, crimp spots (untwisted) and fluff frequently occur, and sick and thin yarns with a small difference in density dyeing are produced, making it practically impossible to develop products. Normally, it was forced to process at a low speed of 400 m / min or less. Therefore, there is a problem that productivity is extremely poor.

[0003]

DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned problems of the prior art, has a good contrast between dark and light (thick and thin pattern), is excellent in crimping performance (TC), and is untwisted. It is an object of the present invention to provide a method for obtaining a special false twisted textured yarn having uniform crimps at a high speed of 500 m / min or more without causing the occurrence of heat.

[0004]

As a result of repeated studies to solve the above-mentioned problems, the inventor of the present invention uses a high-temperature non-contact heater instead of the conventional contact plate type heater and uses it for each part of thick and thin. The present invention found that stable high-speed processing, which was not found in the contact plate type heater, was possible by twisting and selecting a draw ratio corresponding to the processing speed for obtaining stable processing tension at high speed. Has been completed.

That is, according to the present invention, when false twisting a polyester thick and thin yarn in which a thick portion and a thin portion are alternately mixed in the fiber axis direction, a non-contact heater of 300 ° C. or higher is used and the following formula is satisfied. 500m under conditions
A false twisting method for polyester sick and thin yarns, characterized in that friction false twisting is performed simultaneously with stretching at a processing speed of at least 1 minute.

[0006]

[Equation 2]

In the formula, DR represents the draw ratio and DS is the addition.
Indicates the work speed (m / min). In addition, the running yarn length is 20 m
Just downstream of the friction false twisting device measured at a pitch of 0.5 m
Untwisting tension T₂Ratio of the average value of C and its standard deviation σ (C
V%: σ / T₂Average value × 100) is 5 to 12%,
Furthermore, the untwisting tension T on the downstream side of the friction false twisting device ₂And upstream
Twisting tension T₁Ratio T of₂/ T₁Is 0.8 to 1.2
Is preferred.

The polyester thick and thin yarn used in the present invention is a thick and thin yarn composed of polyester having an aromatic dicarboxylic acid as a main acid component and having a fiber-forming ability. Examples of such polyester include polyethylene terephthalate and Examples thereof include polytetramethylene terephthalate, polycyclohexane dimethylene terephthalate, polyethylene-2,6-naphthalene dicarboxylate and the like. Further, these polyesters may be copolymers obtained by copolymerizing other carboxylic acids such as isophthalic acid, 5-sodium sulfoisophthalic acid or other alcohols as the third component, and may be a mixture of these various polyesters. .
Above all, polyethylene terephthalate is the most suitable.

The polyester thick and thin yarn to be false twisted in the present invention has a diameter ratio of the thick portion to the thin portion of 1.2 to 1.5 and a length of the thick portion of 25 to 70 mm.
It is preferable that the thin portion is composed of a filament having a length of 25 to 70 mm. Such a polyester thick and thin yarn has an intrinsic viscosity [IV] of 0.55 to 0.55.
The polyester of 0.7 is melt-spun at 285 to 300 ° C., drawn at a speed of 1000 to 3500 m / min, and drawn at a temperature of the second transition point or lower at a draw ratio of less than the natural draw ratio (NDR), It can be obtained by heat treatment at 80 ° C.

The polyester thick and thin yarn thus obtained is subjected to false twisting simultaneously with stretching using a non-contact heater of 300 ° C. or higher, preferably 400 ° C. or higher. It is necessary to use a non-contact type heater, and it is difficult for the contact type heater to process at a high speed of 500 m / min or more, and the difference in dark and light dyeing (thick and thin pattern) deteriorates. Further, the temperature of the non-contact heater needs to be 300 ° C. or higher. If the temperature is lower than 300 ° C., untwisting occurs and the difference in dark and light dyeing (thick and thin pattern) is deteriorated. is there.

Further, in the present invention, under the condition that the draw ratio DR and the processing speed DS (m / min) satisfy the following equation,
It is necessary to carry out friction false twisting at the same time as drawing.

[0012]

(Equation 3)

When the draw ratio DR is higher than the range represented by the above formula, the crimping performance (TC) is deteriorated and the difference in dark and light dyeing (thick and thin pattern) is deteriorated. on the other hand,
If the draw ratio DR is lower than the range represented by the above formula, untwisting occurs and uniform crimping cannot be obtained.

FIG. 1 is a simplified side view showing an example of a false twisting apparatus for carrying out the method of the present invention. A polyester thick and thin yarn A in which thick portions and thin portions are alternately mixed in the fiber axis direction is shown. , Unwinding via the unwinding guides B and C, and drawn and false twisted between the supply roll D and the first delivery roll J. E is a high temperature non-contact heater in which a guide is provided in the yarn guide, and the twist twisted by the friction false twisting device G is quickly heat-set. The guide guide may be installed, for example, so that the yarn runs in a bowed arc when viewed from one direction perpendicular to the running direction of the yarn. Alternatively, the guide guide may be installed so that the yarn bends and runs. You may. F is a cooling plate, which cools the yarn set by twisting heat to fix its shape, and the yarn set by twisting by the friction false twisting device G is untwisted and expresses bulkiness. As the friction false twisting device G, for example, a triaxial circumscribed friction disc is used, and the material thereof is polyurethane, ceramic, ceramic coat, etc., and the number of discs is appropriately changed depending on the fineness and quality of the yarn to be processed. To use.

On the downstream side of the friction false twisting device G, the untwisting tension T
₂ disposed device H for detecting the tension T ₂ if it is detected is monitored by continuously monitoring apparatus I, this tension pattern, manages the thick and thin patterns of yarn of interest online that You can Furthermore, a non-contact heater K may be arranged between the first delivery roll J and the second delivery roll L to develop crimps on the filaments in accordance with the target crimp level. Therefore, the special false twisted yarn package O can be obtained through the winding guide M and the winding roll N.

Further, in the present invention, a friction false twisting device G
The untwisting tension T ₂ on the downstream side of the
The pitch is measured over 20 m, the standard deviation σ (n = 40) is calculated for the average value of each pitch, and the standard deviation σ
When the ratio (CV% = σ / T ₂ average value × 100) of the untwisting tension T _{2 to} the average value is 5 to 12%, the shade difference (thick and thin pattern) is stable, and false twisting is performed. It is preferable because there is no difference between the weights in the processing machine.

Conventionally, in order to manage the difference in color density (thick and thin pattern), the yarn after false twisting is
U% was measured with an Evenestaster, or it was dyed in a tubular knitting, and the dyeing pattern was visually observed, and the result was fed back to the false twisting processing conditions. There is a problem that the amount of defective products that occur before feedback increases, especially when high-speed processing is performed, and the thick and thin pattern difference between individual weights of the false twisting machine can be fully confirmed. There was a problem that I could not. However, in the present invention, it found that thick and thin patterns corresponds to the variation of the untwisting tension T _2, originally untwisting tension T ₂
The detection and monitoring system that was used to prevent the fluctuation of the untwisted yarn, on the contrary, is used to constantly change the untwisting tension T ₂ within a specific range. It is possible to control the thin pattern online, and it is possible to solve the above-mentioned problems of the conventional method all at once. In order to control the ratio of the average value of the untwisting tension T _{2 to} the standard deviation σ (n = 40) within the range of 5 to 12%, the false twist draw ratio may be adjusted.

Further, in the present invention, if the untwisting tension T ₂ becomes too small, the untwisted portion remains in the false twisted yarn, the crimping performance deteriorates, and uniform crimping cannot be obtained. untwisting the ratio T ₂ / T ₁ in the tension T ₂ and false twisting tension T ₁ is 0.8
It is preferable to control so as to be within the range of 1.2. Untwisting tension T ₂ and 0.8 the ratio T ₂ / T ₁ of the false twist tension T ₁
In order to control within the range of 1.2, the ratio between the false twist disc speed and the yarn running speed may be adjusted.

[0019]

The present invention will be described in more detail with reference to the following examples. Each characteristic value was measured and evaluated by the following methods. (1) Crimping performance (TC) The textured yarn is taken on the crepe, and a light load of 2 mg per denier is applied, and treated for 20 minutes in boiling water, then at 20 ° C, 65%
200 denier after air-drying overnight in the RH room
Applying a heavy load of mg, the length after standing for 1 minute is I ₀ , then removing the heavy load and changing to a light load, the length I after 1 minute
₁ was measured and TC was calculated by the following formula. TC (%) = (I ₀ −I ₁ ) × 100 / I ₀ The larger this value, the better the crimping performance.

(2) Dyeing / dyeing difference (thick and thin pattern) The false twisted yarn is tubular knitted, dyed in blue with Eastman polyester blue, and the dyeing difference pattern is visually observed, and the following criteria It was judged by. Grade 4: Very good Grade 3: Good Grade 2: Pattern is slightly thin and slightly defective Grade 1: Pattern is thin and defective (3) U% Uster Eveness Tester (manufactured by Keisokuki Kogyo KK) is used and the yarn speed is 100 m / Min, chart speed is 2.5 cm / min, and while performing false twisting at 5500 rpm with a false twisting machine, measurement is performed at 1/2 inert.

(4) Standard deviation σ of untwisting tension T ₂ A tension detecting device is provided on the downstream side of the friction false twisting device, and the tension (g) is continuously measured over a running yarn length of 20 m.
The average value was obtained at m pitches, and the standard deviation σ of the obtained 40 data was calculated. (5) Untwisted The false twisted textured yarn was visually observed and judged according to the following criteria. ◯: The untwisted portion does not exist at all, and the crimp is uniform. Δ: Untwisted portions are present in spots, and the crimp uniformity is slightly inferior. X: Non-crimped untwisted portion is present and crimps are non-uniform.

[Examples 1 to 13 and Comparative Examples 1 to 13] Polyethylene terephthalate having an intrinsic viscosity [IV] of 0.65 was melted at 295 ° C., taken at a speed of 1900 m / min and melt-spun, and then 50 Stretched 1.3 times between the supply roll heated to 70 ° C and the stretching roll heated to 70 ° C, and the thick portion (average length 35 mm) and the thin portion (average length 50 mm) are mixed in the fiber axis direction. 195de / 4
8 thick thick and thin yarn (diameter ratio of thick portion to thin portion of 1.3) was obtained.

This thick and thin yarn was subjected to simultaneous drawing and false twisting by the drawing and false twisting device shown in FIG. The draw ratio, the processing speed, and the temperature of the non-contact heater were changed as shown in Tables 1 and 2. The non-contact heater has an effective length of 1 m.
As the friction false twisting device, a device of 3 urethane disks × 3 axis circumscribing system was used.

[0024]

[Table 1]

[0025]

[Table 2]

The results are shown in Tables 3 and 4, and the relationship between the draw ratio DR and the processing speed DS (m / min) was analyzed for the good results and the poor results.
As shown in, it was revealed that good results can be obtained only when the draw ratio DR and the processing speed DS satisfy a specific relationship. In FIG. 2, ◯ indicates an example (a result is good), and x indicates a comparative example (a result is bad).
Indicates.

[0027]

[Table 3]

[0028]

[Table 4]

[Examples 14 to 16 and Comparative Example 14] In Example 8, the temperature of the non-contact heater was changed as shown in Table 5. The results are as shown in Table 6, and the non-contact heater temperature was If the temperature is less than 300 ° C., untwisting occurs, and the difference in dark and light dyeing (thick and thin pattern) becomes poor, but 3
Good results were obtained in the present invention at a temperature of 00 ° C. or higher.

[Comparative Example 15] In Example 8, a contact heater having an effective length of 2.5 m and a temperature of 220 ° C. was used in place of the non-contact heater. The results are as shown in Table 6, in which untwisting occurred and the difference in dark and light dyeing (thick and thin pattern) was also defective.

[0031]

[Table 5]

[0032]

[Table 6]

[0033]

EFFECTS OF THE INVENTION According to the present invention, the specific difference in shade difference (thick and thin pattern) is excellent, the crimping performance (TC) is excellent, the untwisting does not occur, and the crimping is uniform. The false twisted yarn can be manufactured with high productivity at a high speed of 500 m / min or more.

[Brief description of drawings]

FIG. 1 is a schematic side view showing an example of a false twisting apparatus used when carrying out the method of the present invention.

FIG. 2 is a graph showing the relationship between the draw ratio and the processing speed.

[Explanation of symbols]

 A Polyester Thick and Thin Yarn D Supply Roll E Non-contact Heater F Cooling Plate G Friction False Twisting Device H Untwisting Tension Detection Device J 1st Delivery Roll K Crimping Development Heater L 2nd Delivery Roll N N Winding Roll O Processed yarn package

Claims (3)

[Claims] 1. When false-twisting a polyester thick-and-thin yarn in which a thick portion and a thin portion are alternately mixed in the fiber axis direction, a non-contact heater of 300 ° C. or higher is used under the condition that the following formula is satisfied. A false twisting method for polyester sick and thin yarns, characterized in that friction false twisting is performed simultaneously with stretching at a processing speed of 500 m / min or more. [Equation 1] In the formula, DR represents the draw ratio, and DS is the processing speed (m /
Minutes). _{2. The} untwisting tension T ₂ on the downstream side of the friction false twisting device measured at a pitch of 0.5 m over a running yarn length of 20 m.
The ratio (CV%) between the average value of and the standard deviation σ is 5 to
It is 12%, and the false twist processing method of the polyester sick and thin yarn according to claim 1. 3. The untwisting tension T on the downstream side of the friction false twisting device.₂When
Twisting tension T on the upstream side ₁Ratio T of₂/ T₁However, 0.8-1.
3. The polyester sician according to claim 1, which is 2.
Dosing yarn false twisting method.