JPH10245780A - Production of moisture absorbing antistatic polyester fiber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a moisture absorbing antistatic polyester fiber excellent in moisture absorption and antistatic properties, and also in mechanical properties such as a strength and an elongation, in a good working efficiency. SOLUTION: This method for producing a moisture absorbing antistatic polyester fiber is constituted by using a highly oriented and non-stretch yarn composed of a polyester consisting of a main repeating unit of an alkylene terephthalate with which <=3.0mol% 5-sodium sulfoisophthalic acid based on acid component thereof is copolymerized, and having >=0.02 birefringence (Δn), applying a heat-treatment for a relaxation at a constant length or <=5% at a temperature of >= (Tg of the non-stretched yarn + 50 deg.C), applying a polyalkylene glycol having 200-1,000 mean molecular weight so as to attain >=5.0wt.% amount of penetration thereof into the inside of the fiber, then heat- treating at >=100 deg.C temperature and then stretching. here, Tg is a glass transition temperature.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a polyester fiber having excellent hygroscopicity and antistatic properties.

[0002]

2. Description of the Related Art Polyester fibers represented by polyethylene terephthalate have excellent weather (light) resistance, chemical resistance and the like, and are widely used. However, various attempts have been made to obtain fibers excellent in these properties due to poor hygroscopicity and antistatic properties.

For example, Japanese Patent Publication No. 58-39926 proposes a method in which a water-soluble polyester is added before the spinning step to form a filament, and then the water-soluble polyester is removed. Japanese Patent No. -24431 proposes a method in which a fiber product containing a polyethylene oxide and an alkali metal salt of a polyalkylene glycol phosphate polymer is treated with an aqueous alkali solution and then treated with a polyethylene glycol derivative.

[0004] However, in the former, since other substances are kneaded in the spinning process, only fibers having poor mechanical properties such as high elongation can be obtained, and the additive may be decomposed during spinning. In such a case, the fiber is discolored.

[0005] In the latter case, the polyethylene glycol derivative is simply adhered to the fiber surface by post-treatment.
There is a problem that the adhered material is easily removed during the post-process, and the performance is not long-lasting.

[0006]

DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned problems, and is excellent in hygroscopicity and antistatic properties, and excellent in mechanical properties such as strong elongation and the like. An object of the present invention is to provide a method for producing fibers with good operability.

[0007]

Means for Solving the Problems As a result of intensive studies to solve the above-mentioned problems, the present inventors have made it possible to attach polyalkylene glycol to the spun yarn, and to carry out relaxation heat treatment, drawing and the like under appropriate conditions. By doing so, the polyalkylene glycol can be penetrated into the fiber, and without impairing mechanical properties such as high elongation, it has been found that a fiber excellent in hygroscopicity and antistatic properties can be obtained. Reached. That is, the present invention provides a highly oriented polyester having a main repeating unit of alkylene terephthalate, a polyester obtained by copolymerizing 3.0% by mole or less of 5-sodium sulfoisophthalic acid with an acid component, and having a birefringence (Δn) of 0.02 or more. The undrawn yarn is subjected to a relaxation heat treatment of a fixed length or 5% or less at a temperature of Tg + 50 ° C. or more of the undrawn yarn, and the permeation amount of the polyalkylene glycol having an average molecular weight of 200 to 1000 into the fiber is 5.0% by weight or more. After attaching so that
The gist of the present invention is a method for producing a moisture-absorbing and antistatic polyester fiber, which comprises performing a heat treatment at a temperature of 00 ° C. or higher and then drawing. Here, Tg is a glass transition temperature.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail. In the polyester of the present invention, the main repeating unit is composed of alkylene terephthalate, and mainly includes ethylene terephthalate and butylene terephthalate. And it is obtained by copolymerizing 3.0 mol% or less of 5-sodium sulfoisophthalic acid with respect to all the acid components. In addition, a copolymer component such as adipic acid, isophthalic acid, sebacic acid, diethylene glycol, triethylene glycol, or neopentyl glycol may be contained as long as the effects of the present invention are not impaired.

[0009] The copolymerization amount of 5-sodium sulfoisophthalic acid must be not more than 3.0 mol% with respect to all the acid components. When the copolymerization amount exceeds 3.0 mol%, the operability is deteriorated, and the physical properties such as the high elongation of the obtained fiber are reduced. By copolymerizing 5-sodium sulfoisophthalic acid, the polyalkylene glycol can easily penetrate into the fiber. Therefore, if the copolymerization amount of 5-sodium sulfoisophthalic acid is too small, it is necessary to perform a heat treatment for a long time after the adhesion of the polyalkylene glycol in order to sufficiently infiltrate the polyalkylene glycol into the interior of the fiber. As the quality worsens, the physical properties of the fiber also tend to decrease. For this reason, the copolymerization of 5-sodium sulfoisophthalic acid is preferably 1.0 to 3.0 mol%.
It is.

Next, a polyester highly oriented undrawn yarn having a birefringence (Δn) of 0.02 or more is used. Birefringence is
If it is less than 0.02, the swelling due to the polyalkylene glycol adhered in the subsequent step becomes too large, and the resulting fiber has reduced physical properties such as high elongation. The upper limit of the birefringence is not particularly limited, but if the birefringence is too high, the fiber is less likely to swell, and the polyalkylene glycol is less likely to penetrate into the fiber. preferable. In order to obtain an undrawn yarn having a birefringence of 0.02 or more, the winding speed during spinning is generally 2500 m /
It should be at least minutes.

In the present invention, such a highly oriented unstretched yarn is added to the unstretched yarn at a temperature equal to or higher than the Tg of the unstretched yarn plus 50 ° C.
% Of relaxation heat treatment. In this step, the boiling water shrinkage of the undrawn yarn is reduced so that the polyalkylene glycol can easily penetrate into the fiber. That is, the undrawn yarn is subjected to a fixed length or relaxation heat treatment and a treatment of adhering the polyalkylene glycol, and then subjected to a heat treatment at 100 ° C. or more, so that the polyalkylene glycol penetrates into the fiber. At the time of heat treatment at a temperature of 100 ° C. or more, the fiber shrinks greatly and cannot penetrate into the fiber.

[0012] The temperature at the time of heat treatment of constant length or relaxation is Tg + 50 °
If it is less than 30, the shrinkage rate of boiling water cannot be reduced, and the fiber shrinks when polyalkylene glycol is adhered and heat-treated, so that the polyalkylene glycol does not penetrate into the fiber. Further, yarn breakage frequently occurs in the subsequent drawing step. The upper limit of the temperature is not particularly limited, but if the temperature is too high, troubles such as fusion of single yarns may occur.
Preferably, the temperature is about g + 80 ° C.

The relaxation rate during the relaxation heat treatment is 5% or less.
If the relaxation rate exceeds 5%, the orientation is reduced, and troubles such as yarn breakage occur in the subsequent stretching step. On the other hand, if the heat treatment is performed in a tension state exceeding the fixed length, the boiling water shrinkage rate cannot be reduced, and after the polyalkylene glycol is attached, the fiber shrinks during the heat treatment, and the polyalkylene glycol does not penetrate into the fiber. In the subsequent drawing step, yarn breakage frequently occurs.

In the step of attaching the polyalkylene glycol, even if the polyalkylene glycol is attached alone, it is used in combination with an antistatic agent such as a metal salt of a sulfonate compound or a metal salt of a phosphate compound, and a smoothing agent such as a fatty acid ester. May be. Further, it may be attached in the form of an aqueous solution or an emulsion. Among them, it is preferable to mix it with an oil agent and attach it together with the oil agent using an oiling device.

As the polyalkylene glycol, those having an average molecular weight of 200 to 1,000 are used. In the present invention, since a highly oriented undrawn yarn is used as the supply yarn, it is necessary to use a low molecular weight polyalkylene glycol to penetrate the inside of the fiber. However, it is released to the outside of the fiber in a later step, and the effect of hygroscopicity and antistatic property is reduced. If the average molecular weight is larger than 1000, it will be difficult to penetrate the fiber, and the obtained fiber will not be excellent in hygroscopicity and antistatic property. Therefore, it is necessary to use a polyalkylene glycol having an average molecular weight of 200 to 1000 in order to impart excellent hygroscopicity and antistatic property to the fiber. Since it can be easily dissolved or dispersed in water, it can be easily mixed with an oil agent and adhered thereto.

Examples of such a polyalkylene glycol include polyethylene glycol (PEG), polypropylene glycol (PPG), a copolymer of ethylene glycol and propylene glycol (PO / EO), and the terminal or esterification of these compounds. And the like.

The polyalkylene glycol is adhered by the above-mentioned method, but the amount of permeation into the fiber is 5.0% by weight or more, preferably 7.0 to 10.0% by weight. The amount of permeation refers to the amount of permeation into the interior of a fiber obtained by drawing an undrawn yarn.

When the amount of permeation is less than 5.0% by weight, the fiber has poor hygroscopicity and antistatic properties. The higher the permeation amount of the polyalkylene glycol, the more excellent the fiber absorbs and absorbs electricity.However, in order to increase the permeation amount, it is necessary to increase the adhesion amount. Soil adheres to the rollers and other equipment in the post-process, which causes trouble. Therefore, in order to obtain a penetration amount of 7.0 to 10.0% by weight, the amount of adhesion to the undrawn yarn is preferably about 10 to 25% by weight (weight of only polyalkylene glycol).

In the present invention, the permeation amount into the fiber is
The drawn fiber is shaken in n-hexane (bath ratio 1: 100), and the polyalkylene glycol adhered to the surface is washed (when the polyalkylene glycol is mixed with the oil agent, the oil agent is washed together), and then air-dried. Then, the weight (Wa) is measured. Subsequently, using a Soxhlet extractor, the polyalkylene glycol permeated into the fiber is extracted with dimethylformamide, air-dried, the weight (Wb) is measured, and the permeation amount (Ws) is calculated by the following equation. Ws (%) = [(Wa−Wb) / Wb] × 100

In the present invention, the step of subjecting the undrawn yarn to a relaxation heat treatment of a fixed length or 5% or less is carried out in a short time by regulating the relaxation rate to reduce the boiling water shrinkage of the undrawn yarn. However, the fibers themselves do not shrink. Therefore, either of this step and the step of attaching the polyalkylene glycol may be carried out first, but it is more preferable to carry out the fixed-length or relaxation heat treatment step first in order to carry out the workability.

The undrawn yarn to which the above-mentioned fixed length or relaxation heat treatment and polyalkylene glycol are adhered is applied at 100 ° C.
Heat treatment is performed at the above temperature. If the heat treatment temperature is lower than 100 ° C., the polyalkylene glycol cannot penetrate into the fibers. The upper limit of the heat treatment temperature is not particularly limited, but is preferably about 150 ° C. or less in order not to deteriorate the physical properties of the fiber. As the method of heat treatment, after the fixed length or relaxation heat treatment and the polyalkylene glycol are attached to the undrawn yarn, it is once wound up and wound into a shape such as cheese, and introduced into a hot air dryer or a pressure treatment device. And the like. In order to allow the attached polyalkylene glycol to penetrate into the fiber, the heat treatment time is preferably set to about 0.5 to 1 hour.

Further, the undrawn yarn subjected to the above-mentioned heat treatment is drawn. The drawing may be carried out by a conventional method using a roller. The drawing may be carried out at a temperature of about Tg to Tg + 30 ° C. and a magnification of about 1.2 to 1.8 times. Good.

As described above, according to the production method of the present invention,
Polyester fibers having excellent hygroscopicity and antistatic properties, strength of 3.0 to 5.0 g / d and elongation of about 20 to 50% can be obtained.

[0024]

Next, the present invention will be described in detail with reference to examples. In addition, each evaluation in an Example was performed by the following method. (1) Birefringence (Δn) Measured with a POH-type polarizing microscope manufactured by Nikon Corporation. (2) Tg Using a differential scanning calorimeter DSC-7 manufactured by PerkinElmer,
The measurement was performed at a heating rate of 10 ° C./min. (3) Permeation amount of polyalkylene glycol Measured and calculated by the above method. (4) Moisture absorption (%) As in the measurement of the permeation amount of (3), after removing the polyalkylene glycol on the fiber surface, the tube-knitted sample was washed with water, dried at 105 ° C. for 1 hour, and weighed (W). ₀ ) measure,
Then, after being left for 1 hour in a thermo-hygrostat at 50 ° C. and 90% RH, the weight (W ₁ ) was measured, and the moisture absorption was calculated by the following equation. A case where the amount of moisture absorption was 2% or more was regarded as acceptable. Moisture absorption (%) = [(W ₁ −W ₀ ) / W ₀ ] × 100 (5) Electric resistance After removing the polyalkylene glycol on the fiber surface in the same manner as the measurement of the permeation amount of (3), the yarn is removed. Were adjusted to 200,000 denier, and measured in a room at 20 ° C. and 40% RH with a sample length of 5 cm using an electrometer manufactured by Takeda Riken Co., Ltd. A case where the electric resistance was 10 ¹² Ωcm or less was regarded as a pass.

Examples 1 to 8 and Comparative Examples 1 to 8 Using polyethylene terephthalate chips in which the copolymerization amount of 5-sodium sulfoisophthalic acid was changed as shown in Table 1, at a spinning temperature of 295 ° C., as shown in Table 1. By changing the spinning speed, undrawn yarns of various birefringences (Δn) and Tg were obtained. At this time, a spinneret having a circular spinning hole and 36 holes was used.

[0026]

[Table 1]

While taking out the undrawn yarn at a speed of 300 m / min, a contact type heat treatment plate having a length of 30 cm is provided between the rollers, and a relaxation heat treatment (in Example 1, a fixed length heat treatment) is performed.
Polyalkylene glycols of the type and average molecular weight shown in Table 2 were adhered and wound into a cheese shape. At this time, an emulsion oil containing 30% by weight of polyalkylene glycol was applied and applied using an oiling roller, and the amount of adhesion (the amount of adhesion of only polyalkylene glycol) was varied by changing the rotation speed of the oiling roller. Next, while being wound in a cheese shape, a heat treatment is performed for 30 minutes using a hot air drier, and the temperature is taken between the rollers at a speed of 500 m / min.
Drawing was performed at 95 ° C. and a magnification of 1.3 times to produce a 75d / 36f drawn yarn. At this time, as shown in Table 2, the temperature during the relaxation heat treatment (the temperature of the contact heat treatment plate), the relaxation rate, the type of polyalkylene glycol, the average molecular weight, the adhesion amount, and the heat treatment temperature (the temperature of the hot air of the hot air dryer) are shown in Table 2. Various changes were made. Table 2 also shows the measurement results of the permeation amount, moisture absorption, electric resistance, strength, and elongation of the obtained fiber with polyalkylene glycol.

[0028]

[Table 2]

As apparent from Table 2, the fibers obtained by the methods of Examples 1 to 8 have excellent hygroscopicity and antistatic properties,
Performance such as strong elongation was also good. On the other hand, Comparative Example 1
Since the amount of the copolymer component of sodium sulfoisophthalic acid was large, the obtained fiber had low strength. In Comparative Example 2, since an undrawn yarn having a low birefringence was used, the swelling due to the polyalkylene glycol was large, and the obtained fiber was inferior in both strength and elongation. In Comparative Example 3, since the relaxation heat treatment temperature was too low, the boiling water shrinkage rate of the fiber could not be reduced, and in Comparative Example 4, the fiber orientation became low because the relaxation rate was too high, and when both were heat-treated. The fiber shrunk too much, and the yarn was frequently broken in the stretching step, resulting in a fiber having poor strength and elongation. In Comparative Examples 5 and 6, since low-molecular-weight tetraethylene glycol or diethylene glycol was used as the polyalkylene glycol, even if it once penetrated inside the fiber, it was separated from the outside of the fiber by heat treatment or the like, and the obtained fiber was used. Had poor antistatic and hygroscopic properties.
In Comparative Example 7, the amount of permeated polyalkylene glycol was too small, and in Comparative Example 8, the polyalkylene glycol did not sufficiently penetrate into the fibers because the heat treatment temperature was too low. It was inferior in electric conductivity and hygroscopicity.

[0030]

According to the present invention, it is possible to stably produce a moisture-absorbing antistatic polyester fiber which is excellent in hygroscopicity and antistatic properties and excellent in mechanical properties such as strong elongation. It becomes possible.

Claims (1)

[Claims] The main repeating unit is composed of an alkylene terephthalate, a polyester obtained by copolymerizing 3.0% by mole or less of 5-sodium sulfoisophthalic acid with respect to an acid component, and has a birefringence (Δn) of 0.02 or more. The stretched yarn is subjected to a relaxation heat treatment of a fixed length or 5% or less at a temperature not lower than Tg + 50 ° C. of the undrawn yarn and has an average molecular weight of 200 to 1000.
5.The permeation amount of the polyalkylene glycol into the fiber is 5.
A method for producing a moisture-absorbing antistatic polyester fiber, comprising: applying a heat treatment at a temperature of 100 ° C. or higher after adhering so as to be 0% by weight or more, and then drawing. However, Tg
Is the glass transition temperature.