JP2691855B2 - Polyester fiber and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyester fiber and a method for producing the same, and more particularly to a polyester fiber having a high water absorbency, a unique rayon tone and a dry feeling, and a method for producing the same.

[0002]

2. Description of the Related Art Polyester fibers have many excellent properties and are widely used in various apparel applications. However, since they are produced by a melt spinning method, they generally have a smooth fiber surface and a hard feel. However, it has a drawback in terms of texture that it has a unique slimy feeling. As a method for producing a polyester fiber in which such drawbacks are improved, a method of blending polyester and an incompatible polymer with polyester and melt spinning (JP-A-55-16906, etc.) or a composite spinning of polyamide and polyester is performed. A method of treating with a swelling agent of polyamide has been proposed (Japanese Patent Publication No. 61-9427).

Polyester fibers also have the drawback of being inferior in water absorbency and sweat absorbability as compared with natural fibers such as cotton, silk and wool, and semi-synthetic fibers such as rayon and acetate. . In order to improve these, by treating a hollow fiber made of a polyester to which a metal salt of an organic sulfonic acid is added with an alkaline aqueous solution, a water-absorbent polyester fiber having fine pores partially communicating with the hollow portion on the fiber surface is obtained. It has been proposed (Japanese Patent Publication No. 61-60188, Japanese Patent Publication No. 62-44065, etc.).

[0004]

However, the method of simply blending different kinds of polymers improves the texture to some extent, but has the drawback of poor water absorption. In addition, the hollow polyester fiber whose fiber surface is microporous,
Although the water absorption was improved, the texture was not improved to a satisfactory degree, and further, a special spinneret was required to make the hollow polyester, and there was a drawback that the manufacturing cost increased. . INDUSTRIAL APPLICABILITY The present invention has a problem in the texture surface that a polyester fiber has conventionally, such as a hard touch and a peculiar slimy feeling on the fiber surface, and a problem in terms of water absorption and sweat absorption. SUMMARY OF THE INVENTION It is an object of the present invention to provide a polyester fiber having a high water absorbency and a unique rayon-like texture and dry feeling.

[0005]

The present invention comprises ethylene terephthalate as a main repeating unit, an organic sulfonic acid metal salt represented by the following formula (1) and an average molecular weight of 10,
A fiber made of polyester containing 000 or less polyethylene, which is a polyester fiber satisfying the following conditions (A) and (B): R-SO ₃ M (1) where R is the number of carbon atoms. 3 to 30 alkyl group or 7 carbon atoms
To 40 aryl groups or alkylaryl groups, M is an alkali metal (A): a large number of continuous streaky grooves oriented in the fiber axis direction are formed on the fiber surface, and the grooves have a width of 0. 1-3 μm, length 5
The distance between adjacent grooves is 5 μm or less (B): 5% of the total cross-sectional area in the fiber cross section inside the fiber
It has irregular voids occupying the above, at least a part of the voids communicates with the streak grooves on the fiber surface, and with respect to the polymer before completion of the polycondensation reaction of the polyester containing ethylene terephthalate as the main repeating unit. A mixture of the organic sulfonic acid metal salt represented by the above formula (1) and polyethylene having an average molecular weight of 10,000 or less, preferably a mixture having a weight ratio of 95: 5 to 50:50 was used.
The polyester polymer obtained by adding 1 to 8 wt% to complete the polycondensation reaction is melt-spun, and the obtained fiber is
This is a method for producing a polyester fiber, which comprises performing a dry heat treatment for 10 seconds or more at a temperature of not less than 0 ° C. and then performing a weight reduction treatment with an aqueous solution of an alkali compound at a weight reduction rate of 5 wt% or more.

The fiber of the present invention comprises ethylene terephthalate as a main repeating unit, and is composed of a polyester containing an organic sulfonic acid metal salt represented by the formula (1) and polyethylene having an average molecular weight of 10,000 or less.

The polyester, which is the main constituent of the fiber of the present invention, has ethylene terephthalate as a main repeating unit, and terephthalic acid or its ester-forming derivative is used as a dicarboxylic acid component, and ethylene glycol or its ester-forming derivative is used. A typical example is a polyester having a glycol component as a glycol component, but a part of the dicarboxylic acid component may be replaced with another dicarboxylic acid component, or a part of the glycol component may be replaced with another glycol component. .

Other dicarboxylic acid components include isophthalic acid and monoalkali metal salts of 5-sulfoisophthalic acid,
Dicarboxylic acids such as naphthalenedicarboxylic acid, diphenyldicarboxylic acid, diphenylsulfonedicarboxylic acid, adipic acid, sebacic acid and 1,4-cyclohexanedicarboxylic acid or esters thereof, and p-oxybenzoic acid, p
And oxycarboxylic acids such as -β-oxyethoxybenzoic acid and esters thereof.

As other glycol components, 1,
4-butanediol, alkylene glycol having 2 to 10 carbon atoms, 1,4-cyclohexanedimethanol, neopentyl glycol, 1,4-bis (β-oxyethoxy) benzene, bisglycol ether of bisphenol A, polyalkylene glycol, etc. Is mentioned.

Further, polycarboxylic acids such as trimellitic acid and pyromellitic acid, polyols such as pentaerythritol, trimethylolpropane and glycerin, monohydric polyalkylene oxides and phenyl are used as long as the polyester is substantially linear. It does not matter even if a polymerization terminator such as acetic acid is used.

The polyester may be synthesized by any known method. For example, in the case of polyethylene terephthalate, terephthalic acid and ethylene glycol are directly esterified, a lower alkyl ester of terephthalic acid such as dimethyl terephthalate is transesterified with ethylene glycol, or terephthalic acid is ethylene oxide. To synthesize a glycol ester of terephthalic acid and / or a low polycondensate thereof, followed by polycondensation of the product by a conventional method. Further, in synthesizing the polyester in the present invention, a known catalyst,
An antioxidant, a coloring inhibitor, an ether bond by-product inhibitor, a flame retardant, and other additives may be appropriately used.

Preferred examples of the organic sulfonic acid metal salt represented by the formula (1) contained in the polyester constituting the fiber of the present invention include butyl sulfonic acid, hexyl sulfonic acid, octyl sulfonic acid and decyl sulfone. Acid, sodium salt of lauryl sulfonic acid, myristyl sulfonic acid, palmityl sulfonic acid, stearyl sulfonic acid, etc., potassium salt, lithium salt, or toluene sulfonic acid, sodium salt of dodecylbenzene sulfonic acid,
Examples thereof include potassium salt, lithium salt, or a mixture thereof.

The organic sulfonic acid metal salt does not have to be a single compound, and may be a mixture of various organic sulfonic acid metal salts. However, these organic sulfonic acid metal salts which are usually commercially available contain impurities of inorganic salts such as sodium chloride and sodium sulfate. These impurities impair the stability of melt spinning. Therefore, it is desirable that the amount of the inorganic salt contained in the organic sulfonic acid metal salt used in the present invention is as small as possible, preferably 0.5 wt% or less of sodium chloride, and more preferably 0.2.
By setting the content to be not more than wt% and the content of sodium sulfate to be not more than 0.1 wt%, it is possible to suppress an increase in back pressure and yarn breakage during melt spinning.

The polyethylene contained in the polyester constituting the fiber of the present invention has an average molecular weight of 10,000 or less for the purpose of reducing the high melt viscosity of the organic sulfonic acid metal salt as a mixture with the organic sulfonic acid metal salt. A low-viscosity polyethylene having a viscosity of 5,000 or less is preferably used.

The polyester constituting the fiber of the present invention includes an organic sulfonic acid metal salt and an average molecular weight of 10,000.
The following polyethylene is contained, and the content thereof is an amount relative to the amount added in the production of the fiber of the present invention. The organic sulfonic acid metal salt is 0.5 to 5 wt.
%, Polyethylene is contained in an amount of 0.1 to 2 wt%, and a mixture of the two is included in an amount of 0.5 to 5 wt%.

In the present invention, the inclusion of the organic sulfonic acid metal salt and polyethylene in the polyester improves the water absorption of the polymer itself, and at the same time, forms voids and reduces alkali in the polyester fiber obtained by melt spinning. It is an essential requirement for forming a large number of streak grooves on the surface of the fiber after the treatment. Although it is possible to form streak grooves in the fiber even if only organic metal sulfonate is contained, the formation of streak grooves on the fiber surface is remarkably exhibited by the coexistence of polyethylene, and high water absorption and excellent Gives the fiber a nice texture.

Further, in the present invention, the above conditions (A) and (B) give a water absorbing property to the polyester fiber by the synergistic effect of both, and improve the texture to impart a rayon-like texture and a dry feeling. It is a necessary condition to do. Regarding the condition (A), the width of the streak groove is 0.1.
If the length is less than 3 μm or more than 3 μm, or if the length of the streak groove is less than 5 μm, it is not possible to impart water absorption to the fiber, which is the object of the present invention, and also the texture is improved and the slimy feel is reduced. Resolution is insufficient.

Referring to the condition (B), in the present invention, the polyester fiber has a large number of irregular voids, which makes it possible to impart an excellent texture to the polyester fiber. The voids alleviate the rigidity of the polyester fiber and give the fiber flexibility, and, in combination with the condition (A), give the fiber a soft touch and a dry feel. In addition, at least a part of the irregular voids communicates with the fiber surface through the recesses of the linear grooves, which makes it possible to impart a high degree of water absorption to the polyester fiber, and when the fiber is dried. The quick-drying property of can also be applied at the same time.
When there is no such void or the ratio of voids in the fiber cross section is less than 5%, the above-mentioned flexibility, water absorption,
Quick drying is not obtained.

In producing the polyester fiber of the present invention, at the stage of synthesizing a polyester polymer having ethylene terephthalate as a main repeating unit, an organic sulfone is added to a low polycondensate or a polymer before completion of the polycondensation reaction of polyester. Acid metal salt and average molecular weight of 10,
Mixture with polyethylene of 000 or less, preferably 95: 5 by weight ratio of organic sulfonic acid metal salt: polyethylene.
It is necessary to add a 50:50 mixture to the reaction system at 0.1 to 8 wt% to complete the polycondensation reaction. It is difficult to uniformly add the organic sulfonic acid metal salt alone because the organic sulfonic acid metal salt has a high melt viscosity, but by using the organic sulfonic acid metal salt as a mixture with polyethylene, the melt viscosity decreases, Facilitates the addition of polyester into the reaction system. The mixture may be added at any stage before the completion of the polyester polycondensation reaction, but it is preferably added during the polycondensation reaction.

A polyester containing a mixture of an organic sulfonic acid metal salt obtained by completing the polycondensation reaction and polyethylene having an average molecular weight of 10,000 or less is melt-spun and formed into fibers through a spinning process. However, in melt-spinning such polyester, it is not necessary to use a special method, and any melt-spinning method for producing polyester fibers can be used. The polyester fiber of the present invention is not only a fiber containing the polyester polymer of the present invention as a single component, but also a fiber having a structure capable of developing continuous streak grooves and irregular voids under the conditions (A) and (B). It suffices if it is present, and may be a core-sheath composite fiber or a side-by-side composite fiber having the polyester polymer of the present invention as a sheath component, a laminating component.

Further, in the present invention, after melt spinning, the obtained fiber is optionally subjected to drawing heat treatment and false twisting, and then at a temperature of 120 ° C. or higher, preferably 140 ° C. or higher, It is necessary to perform dry heat treatment for 10 seconds or longer, preferably 20 seconds or longer. This dry heat treatment is necessary mainly for forming irregular voids inside the fiber.
The dry heat treatment of less than 20 ° C. or less than 10 seconds does not form irregular voids inside the fiber which is the object of the present invention.
Here, this dry heat treatment is disadvantageous in terms of process speed if it is carried out in the processes of stretching heat treatment and false twisting, and it is industrially difficult, so it is preferable to apply it after forming it into a woven or knitted material.

Further, in the present invention, the yarns, preferably woven or knitted, are subjected to weight reduction treatment with an aqueous solution of an alkali compound. This weight reduction treatment with an alkaline compound is necessary as a treatment for communicating the fiber surface with the voids inside the fiber and for removing a part of the fiber surface to form many streak grooves on the fiber surface. In order to form the grooves on the fiber surface, the weight reduction treatment is performed at a weight reduction rate of 5 wt% or more, preferably 10 wt% or more.

Examples of the alkali compound used in the alkali reduction treatment of the present invention include sodium hydroxide, potassium hydroxide, tetramethylammonium hydroxide, sodium carbonate and potassium carbonate. Of these, sodium hydroxide and potassium hydroxide are particularly preferably used. Although the concentration of the aqueous solution of the alkaline compound varies depending on the type of the alkaline compound, the treatment conditions, etc., it is usually preferably in the range of 0.1 to 30 wt%. The treatment temperature is preferably room temperature to 100 ° C., and the treatment time is usually 1 minute to 4 hours.

The polyester fiber of the present invention obtained as described above has a large number of continuous streaky grooves oriented in the fiber axis direction over the entire circumference of the fiber surface, as shown in FIG. At the same time, a large number of random and irregular voids are present inside the fiber in the axial direction of the fiber, and at least a part of the voids is a fiber having a structure in which continuous voids are formed on the fiber surface. Due to the large number of continuous streaky grooves on the surface of the fiber and the large number of irregular voids inside the fiber, such polyester fibers have a rayon-like dry texture, water absorption performance, and sweat absorption that conventional polyester fibers do not have. Express performance.

[0025]

The present invention will be described below in more detail with reference to examples. The characteristic values in the examples are measured by the following methods. In addition,% and parts in the examples mean wt% and parts by weight, respectively. In addition, ◯, Δ, and × in the table represent good, slightly good, and bad, respectively.

Intrinsic viscosity: A sample was dissolved in a mixed solvent of phenol / tetrachloroethane = 50/50 and measured at 25 ° C. with an Ubbelohde viscometer. Melt viscosity: A sample (mixture for addition) was sufficiently melted at a predetermined temperature in a nitrogen atmosphere and measured by a B-type viscometer. Water absorption performance: After weaving the obtained raw yarn under the following conditions, warp: polyester normal yarn (50 denier / 18 filaments) weft: original yarn of the present invention (75 denier / 36 filaments) warp weave density: 39 0.5 yarns / cm Weft weave density: 33.9 yarns / cm Scouring and presetting were performed according to a conventional method, and weight reduction treatment was performed at a boiling temperature using a 2% sodium hydroxide aqueous solution. Attach the resulting fabric to a circular frame for embroidery with a diameter of 15 cm,
The water absorption performance was evaluated by measuring the disappearance time of water droplets on the fabric by the water droplet dropping method. Distilled water was used for the water droplets, the distance between the tip of the burette and the fabric surface was 1.0 cm, and one water droplet was dropped on the fabric, and the disappearance time was measured. The measurement was performed at a room temperature and a relative humidity of 55 to 60%, the measurement was repeated 5 to 7 times for each sample, and the average water droplet disappearance time was obtained.
The average amount of one water drop at this time was 0.039 ml.

Example 1 100 parts of terephthalic acid and 52 parts of ethylene glycol were charged into an esterification tank and 4 kg.
The esterification reaction was carried out at 260 ° C. under a pressure of / cm ² . Subsequently, trimethyl phosphate, antimony trioxide, and titanium dioxide were added to the obtained reaction product in an amount of substantially 0.01%, 0.04% with respect to the produced polymer, respectively.
It was added as an ethylene glycol dispersion so as to be 0.5%, and transferred to a polymerization tank. Then, a polycondensation reaction was carried out at 285 ° C. under high vacuum for 70 minutes, and at this time, sodium alkylsulfonate mainly composed of sodium pentadecylsulfonate (manufactured by Matsumoto Yushi Co., Ltd., containing sodium chloride and sodium sulfate as impurities). The amount is 0.02%,
0.05%) 70 parts and 30 parts of polyethylene having an average molecular weight of 2,000 (mixture C) are added to the reaction system so as to be 2% with respect to the produced polymer, and then polycondensation reaction is performed for a predetermined time. A polyester polymer having an intrinsic viscosity of 0.71 was obtained. The mixture C was melted at 170 ° C. and added, and the melt viscosity at 170 ° C. was 85 poise.

This polymer was made into chips by a conventional method, dried, and melt-spun at 285 ° C. through a spinneret having 36 circular spinning holes with a hole diameter of 0.25 mm. After the discharged yarn is cooled and solidified with a cooling air flow, an oil agent is applied and 1800 m
It was wound at a winding speed of 1 / min. Then, this undrawn yarn was drawn and heat-treated according to a conventional method to obtain a drawn yarn of 75 denier / 36 filament.

The drawn yarn obtained is knitted into a knitted fabric,
After performing a dry heat treatment at 180 ° C. for 60 seconds, an alkali weight reduction treatment was performed at a boiling temperature in a 2% sodium hydroxide aqueous solution. The state of void formation inside the fibers of the obtained knitted fabric was observed with a scanning electron microscope. The observation results are shown in FIG. 1 and Table 1. Further, the obtained drawn yarn is woven,
Similarly, as shown in Table 1, the texture of the woven fabric obtained by the dry heat treatment and the alkali weight loss treatment had a good texture and a rayon-like dry feeling.

[0030]

[Table 1]

Further, Table 2 shows the water absorption performance of the obtained polyester fiber drawn yarn.

[0032]

[Table 2]

(Examples 2 to 11, Comparative Examples 1 to 4) The same as Example 1 except that the addition amount of the mixture C in Example 1 and the temperature and time of the dry heat treatment were changed as shown in Table 1. Was carried out to obtain a knitted fabric which was subjected to dry heat treatment and alkali weight loss treatment. Table 1 shows the observation results of the fibers of the obtained knitted fabric and the texture of the woven fabric subjected to the alkali reduction treatment similar to the knitted fabric. The water absorption performance of the polyester fiber drawn yarns obtained in Examples 2 and 8 is shown in Table 2.

(Examples 12 to 16 and Comparative Examples 5 to 6) The mixture C of Example 1 was mixed with sodium alkylsulfonate and polyethylene at a mixing ratio of 90 parts: 10 parts (mixture A), 80 parts: 20 parts. Mixture (mixture B), 60
Parts: A knitted fabric subjected to dry heat treatment and alkali weight reduction treatment in the same manner as in Example 1 except that 40 parts of the mixture (mixture D) was added and the addition amounts thereof were changed as shown in Table 3. Got The melt viscosities of the mixtures A, B, and D at 170 ° C. were 190 poise, 130 poise, and 15 poise, respectively. Table 3 shows the observation results of the fibers of the obtained knitted fabric and the texture of the woven fabric. In Comparative Examples 5 and 6, the stability of the yarn-forming process was poor, and fiberization was not possible.

[0035]

[Table 3]

(Comparative Example 7) In Example 1, the mixture C was used.
Instead of sodium alkyl sulfonate, it was attempted to add it by melting it into the polycondensation reaction system.
It was extremely high at 0 poise, and it was difficult to quantitatively add it to the reaction system.

[0037]

As shown in FIG. 1, the polyester fiber of the present invention has a fiber surface composed of a large number of continuous streaky grooves highly oriented in the fiber axis direction, and has at least one of them. The polyester fiber of the present invention has a large number of irregular voids communicating with the surface of the fiber inside the fiber, and the polyester fiber of the present invention has a high water absorbency and a rayon-like unique characteristic based on the surface and internal structure of the fiber. It has a feeling of dryness. Therefore, when the polyester fiber of the present invention is obtained in the form of a woven or knitted fabric, it naturally gives the woven or knitted fabric a high water absorbency, a unique rayon-like texture and a dry feeling.

[Brief description of the drawings]

FIG. 1 is a scanning electron micrograph showing the surface and cross section of an example of a polyester fiber of the present invention at a magnification of 2,000.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location D01F 6/92 308 D01F 6/92 308H D06M 11/38 D06M 5/02 F // D06M 101: 32 (56) References JP-A-1-239159 (JP, A) JP-A-1-183574 (JP, A) JP-A-60-20963 (JP, A)

Claims (2)

(57) [Claims] 1. A fiber comprising a polyester containing ethylene terephthalate as a main repeating unit and containing an organic sulfonic acid metal salt represented by the following formula (1) and polyethylene having an average molecular weight of 10,000 or less, wherein ) And (B) are satisfied, the polyester fiber characterized by the above-mentioned. R-SO ₃ M (1) However, R is an alkyl group having 3 to 30 carbon atoms or 7 carbon atoms.
To 40 aryl groups or alkylaryl groups, M is an alkali metal (A): the fiber surface has a large number of continuous streak grooves oriented in the fiber axis direction, and the grooves have a width of 0. 1-3 μm, length 5
The distance between adjacent grooves is 5 μm or less (B): 5% of the total cross-sectional area in the fiber cross section inside the fiber
It has irregular voids occupying the above and at least part of the voids communicates with the streak-like grooves on the fiber surface. 2. A mixture of a metal salt of an organic sulfonic acid represented by the above formula (1) and polyethylene having an average molecular weight of 10,000 or less with respect to a polymer before completion of a polycondensation reaction of a polyester containing ethylene terephthalate as a main repeating unit. Of 0.1% to 8% by weight to complete the polycondensation reaction, the polyester polymer obtained is melt-spun, and the obtained fiber is dry heat treated for 10 seconds or more at a temperature of 120 ° C. or more,
The method for producing a polyester fiber according to claim 1, wherein the weight reduction treatment is performed with an aqueous solution of an alkali compound at a weight reduction rate of 5 wt% or more.