JP2600032B2 - Method for producing ultrafine polyester fiber - Google Patents

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 ultrafine polyester fiber having a thickness of 0.1 denier or less. More specifically, a polyester is obtained by mixing polyethylene and an acid-modified polyolefin into a mixed spun fiber, and then dissolving and removing the polyethylene and the acid-modified polyolefin to obtain an extremely fine polyester fiber stably and at low cost. It relates to a manufacturing method.

[0002]

2. Description of the Related Art In recent years, various types of ultrafine fibers have been developed, and their applications are expanding to high-performance synthetic paper, high-performance filters, high-grade artificial leather base fabrics, high-grade woven and knitted fabrics, and the like. Among such ultrafine fibers, particularly fine, a method for producing ultrafine fibers having a thickness of 0.1 denier or less is to form a mixed spun fiber from two or more incompatible polymer components, and then to form a mixed spun fiber in the mixed spun fiber. Methods for dissolving and removing at least one polymer component are known.

For example, Japanese Patent Publication No. 44-21167 discloses that a mixed spun fiber composed of nylon 6 or polyester and polyoxymethylene is formed, and then the nylon 6 or polyester in the mixed spun fiber is dissolved or decomposed and removed. Thus, a method for producing a microfilament made of polyoxymethylene is disclosed. However, such a method cannot obtain a polyester ultrafine fiber.

Further, Japanese Patent Publication No. 42-19518, Japanese Patent Publication No. 56-16235, and Japanese Patent Publication No. 58-38533
JP, JP-A-61-252362, JP-A-63
JP-A-243314 and the like describe the formation of a mixed spun fiber composed of polyester and polyethylene, but in these spinning steps, the spinning condition is unstable, yarn breakage frequently occurs, and workability is poor. , The cost is high, and the thickness irregularity of the island component of the obtained fiber is large,
In particular, when it is made into a leather-like sheet material as shown in JP-B-56-16235, the flexibility is low, and the strength performance such as tear strength, tensile strength, and kneading strength causes a defect,
There has been a problem that staining spots are generated and the quality is significantly reduced.

Further, when spinning a mixed spun fiber composed of polyester and polyethylene, Japanese Patent Publication No. 42-195
As described in Japanese Patent Publication No. 18, polyethylene depending on the melting method and spinning conditions, polyethylene to be eluted with a solvent such as xylene or toluene becomes an island component, and polyester to be made into a fine fibril becomes a sea component. After the elution treatment, it is easy to form fine porous hollow fibers of polyester,
There was a problem of being very unstable.

Japanese Patent Application Laid-Open No. 49-529 discloses that a mixed spun fiber is formed by using polyester, polyethylene and polyethylene glycol as a fiprilation-promoting agent, and thereafter the mixed spun fiber is beaten to obtain a fiprillized fiber. A method for doing so is disclosed.

Although it is possible to produce ultrafine polyester fibers by this method, it is easy for polyethylene glycol to absorb moisture, so that it is difficult to handle and the spinning quality tends to deteriorate. In addition, since the melting point is low, the melting characteristics in a melt spinning machine are poor, and there is a drawback that extrusion of a molten polymer becomes unstable. Therefore, there has been a demand for a solution to these problems in a method for producing an ultrafine polyester fiber.

On the other hand, in these publications, polyester,
There is no specific disclosure of a method for forming a mixed spun fiber from polyethylene and an acid-modified polyolefin, and dissolving and removing polyethylene and the acid-modified polyolefin from the obtained mixed spun fiber.

[0009]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and has as its object to provide excellent handling properties in a melt spinning process and excellent process stability during spinning and stretching. It is an object of the present invention to provide a method for producing ultrafine polyester fiber which can be produced at low cost.

[0010]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to achieve the above object, and as a result, when a specific modified polyolefin is used in combination with polyethylene when mixing with polyethylene, the viscosity characteristics of the molten mixture are reduced. At the same time, the spinning properties are extremely improved and polyethylene is not an island component at all, but is a stable sea component.Polyester is a stable, ultra-fine island component with little unevenness in thickness. I learned that polyester fibers can be produced stably and inexpensively. As a result of further study based on such findings, the present invention has been achieved.

That is, according to the present invention, a mixture comprising a polyester (A), a polyethylene (B) and an acid-modified polyolefin (C) and simultaneously satisfying the following and formulas is melt-spun and drawn to have a single fineness of 1%. process for producing a 15 denier mixed spun fibers, _{and, W a: W B = 30~60} : 70~40 W C / (W a + W B) = 0.01~0.30 [However, W _a, W _B, W _C is contained in each said mixture (a), (B), removing dissolved polyethylene (B) and acid-modified polyolefin (C) from the weight] obtained mixed spun fibers (C) A process for producing an ultrafine polyester fiber having a thickness of 0.1 denier or less.

The polyester (A) used in the present invention
Is terephthalic acid, isophthalic acid, naphthalene-2,6
-Aromatic dicarboxylic acids such as dicarboxylic acids, fumaric acid,
Aliphatic dicarboxylic acids such as adipic acid and sebacic acid or esters thereof, and ethylene glycol, diethylene glycol, 1,4-butanediol, neopentyl glycol, 1,6-hexanediol, cyclohexane-1,4-dimethanol, etc. And a polyester synthesized from a diol compound of the formula (1), and polyethylene terephthalate and polybutylene terephthalate are particularly preferable.

The above polyester component may be copolymerized with polyalkylene glycol, glycerin, pentaerythritol, methoxypolyalkylene glycol, bisphenol A, sulfoisophthalic acid, or the like. Further, polyesters synthesized by self-condensation of oxycarboxylic acids and polyesters in which 70% or more of the repeating structural units are oxycarboxylic acid polymers can also be used.

As the polyester (A) of the present invention, 3
The intrinsic viscosity measured in an o-chlorophenol solution at 5 ° C is preferably in the range of 0.3 to 1.5, particularly preferably 0.55 to
A range of 1.2 is more preferred. If the intrinsic viscosity is less than 0.3, the melt viscosity is too low, the spinning condition is poor, and the polyester (A) tends to be a sea component. If it exceeds 1.5, the melt viscosity becomes too high, and melt extrusion during spinning becomes difficult.

Further, as the polyethylene (B) used in the present invention, any polyethylene generally used industrially can be used, and a low-density polyethylene having a density of 0.910 to 0.925, and a density of 0.926 to 0.925 are also used. 0.940 medium density polyethylene, same density 0.941 ~ 0.96
5 may be any of the high-density polyethylenes. Among them, those marketed as low-density polyethylene,
It is particularly preferable from the viewpoints of handling properties, melting properties, spinnability, stretchability in a hot water bath, and dissolving and removing properties. Further, the melt index of such polyethylene is preferably in the range of 5 to 100.

The acid-modified polyolefin (C) used as a mixture with the polyester (A) and the polyethylene (B) is obtained by dispersing the polyester component finely in the polyethylene component and finally obtaining the diameter of the polyester fiber. In the present invention, it plays an important role in reducing the unevenness, reducing the spots, and improving the spinning drawability.

As the acid-modified polyolefin (C), a random copolymer, block copolymer or graft copolymer may be used as long as it is a polyolefin obtained by copolymerizing a monomer (D) having a carboxyl group or a carboxylic ester group in the molecule. Any copolymer may be used. In addition, the polyolefin targeted here is a polymer or a copolymer mainly composed of α-olefin such as ethylene, propylene, and butene-1 such as polyethylene,
Any of polypropylene, polybutene-1, polyethylene propylene copolymer and the like can be used.

The polyolefin-modifying monomer (D) may be any of unsaturated carboxylic acids and their esters or acid anhydrides. As the unsaturated carboxylic acid preferably used, acrylic acid, methacrylic acid, maleic acid, fumaric acid and the like can be mentioned,
Examples of unsaturated carboxylic acid esters include acrylates such as methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate and 2-hydroxyethyl acrylate; methyl methacrylate, ethyl methacrylate, butyl methacrylate; Methacrylic acid 2-
Examples include methacrylic acid esters such as ethylhexyl; diethyl maleate; diethyl fumarate; and unsaturated carboxylic anhydrides include maleic anhydride, itaconic anhydride and the like. The acid-modified polyolefin (C) used in the present invention uses one or more of these copolymer components.

The copolymerization ratio of the copolymer component to the olefin is preferably 0.1 to 15 mol% based on the olefin from the viewpoint of the effects and the effects of the modified polyolefin (improvement in dispersibility, spinning drawability, etc.). When the copolymerization ratio is less than 0.1 mol%, the polyester (A) cannot be finely dispersed in the polyethylene (B), and the polyester component (A) becomes a large island-like in the polyethylene (B). And the distribution unevenness of the diameter becomes large, so that the spinning drawability is extremely lowered. On the other hand, if the copolymerization ratio exceeds 15 mol%, the melting point or softening point of the acid-modified polyolefin (C) is extremely lowered, which is not preferable in terms of melting characteristics.

Further, the melt index value of the acid-modified polyolefin is preferably in the range of 1 to 100, and if it is less than 1, the fluidity during melt spinning becomes insufficient and the spinning speed must be reduced. Tend to be less. In addition, the effect of fine dispersion of the polyester (A) is reduced (because the melt viscosity of the acid-modified polyolefin (C) becomes too high and the mixing efficiency with other components is reduced), so that the finally obtained ultrafine polyester fiber The quality tends to be inferior. On the other hand, when the melt index value exceeds 100, the spinning condition is remarkably reduced, and the diameter of the obtained polyester fiber tends to be too large.

Among the above-mentioned acid-modified polyolefins (C) used in the present invention, the modified polyolefin obtained by copolymerizing methyl methacrylate and maleic anhydride and having a melt index value of 5 to 50 is the polyester (A). It is particularly preferable from the viewpoint of improving dispersibility, reducing and uniforming the fiber diameter of the polyester component, and improving spinnability.

In the present invention, the above-mentioned polyester (A), polyethylene (B), and acid-modified polyolefin (C) are melt-spun after being mixed so as to simultaneously satisfy the following and formula. _{W A: W B = 30~60:} 70~40 W C / (W A + W B) = 0.01~0.30

Preferably, the mixture is melt-spun after mixing to satisfy the following formulas (1) and (2). 'W _A : W _B = 35 to 45:65 to 55' W _C / (W _A + W _B ) = 0.02 to 0.25 [where W _A , W _B , and W _C are contained in the above mixture, respectively. Weight of (A), (B) and (C)

When the mixing ratio of (A) and (B) is out of the range of the formula, polyester ultrafine fibers cannot be obtained. On the other hand, when W _C / (W _A + W _B ) is less than 0.01,
Polyester (A) is unlikely to become ultrafine fibers, 0.30
In the case where the value exceeds, the spinning property of the mixed spun fiber is poor, so that it is inappropriate.

As a mixing method, a mixture obtained by mixing a polyester chip, a polyethylene chip and an acid-modified polyolefin with a chip blender or the like is introduced into an ordinary melt spinning apparatus, and a polyester, a molten polyester,
Any method such as a method of mixing polyethylene and an acid-modified polyolefin in a pack of a melt spinning apparatus can be adopted.

When mixing the components (A), (B) and (C), if necessary, an antistatic agent, a matting agent such as titanium dioxide, a coloring agent such as carbon black, a heat-stable antioxidant, etc. Can be added and mixed.

The temperature of the melt spinning is preferably from 265 to 300 ° C., and the winding speed of the undrawn yarn is preferably from 500 to 1,500 m / min. The obtained undrawn yarn is then drawn and has a thickness of 1-1.
It becomes a mixed spun fiber of 5 denier. Stretching temperature is 50 ~
95 ° C., stretching ratio 3-5 times, stretching speed 50-300
m / min is preferred.

Next, in the present invention, substantially all of the polyethylene (B) and the acid-modified polyolefin (C) are dissolved and removed from the mixed spun fiber obtained as described above. Polyethylene (B) and acid-modified polyolefin (C)
Can be easily performed by immersing the mixed spun fibers in a hydrocarbon solvent such as toluene, xylene, decalin, or tetralin at room temperature or while heating. The dissolution property by the solvent is greatly improved by the presence of the acid-modified polyolefin (C).

The removal of the component (B) and the component (C) may be performed in the state of the yarn of the mixed spun fiber, or may be performed after forming a nonwoven fabric, a woven fabric, a knitted fabric or the like from the mixed spun fiber. . Alternatively, it may be performed after the cloth is brushed or processed with a resin such as a polyurethane resin.

When the polyethylene (B) and the acid-modified polyolefin (C) are dissolved and removed from the mixed spun fiber as described above, the ultrafine polyester fiber of the present invention having a thickness of 0.1 denier or less is obtained.

[0031]

The present invention will be described in detail with reference to the following examples. In addition,
All parts in the examples mean parts by weight. In the examples, the spinning drawability and dispersibility of the mixed spun fibers were evaluated as follows. Spin drawability : indicates the ease of spinning and drawing of the mixed spun fiber. Excellent: The polyester (A) component and the polyethylene (B) component hardly peeled off, and spinning and stretching can be performed well. Good: A little peeling occurred, but spinning and stretching were possible. Poor (1): Difficulty of spinning and poor stretchability Poor (2): Very peeling occurred and difficult to spin and draw Poor (3): Melt softened too much and made spinning difficult

Dispersibility : indicates whether or not polyester (A) becomes ultrafine fibers when polyethylene (B) and acid-modified polyethylene (C) in the mixed spun fibers are completely dissolved and removed. ：: Extra fine fibers of polyester (A) separated from each other are obtained. ×: Porous fiber of polyester (A) (not very fine)
Is obtained.

Examples 1 to 5, Comparative Examples 1 to 4 Polyethylene terephthalate chips having an intrinsic viscosity of 0.64 measured at 35 ° C. in an o-chlorophenol solution,
4 parts each of methyl methacrylate and maleic anhydride
The mol-% and 0.2 mol-% copolymerized acid-modified polyethylene having a melt index of 30 were mixed in the amounts shown in Table 1 using a chip blender. Thereafter, high-pressure low-density polyethylene chips having a melt index of 30 were added and mixed in the amounts shown in Table 1 to obtain a mixture of polyester, polyethylene and acid-modified polyethylene.

This mixture was introduced into an ordinary melt spinning apparatus having 600 spinning holes, and spun at a spinning temperature of 290 ° C. and a spinning speed of 1,000 m / min to obtain an undrawn yarn. This end drawn yarn is drawn at a drawing temperature of 70 ° C. and a drawing speed of 100 m / min.
The fiber was drawn five times to obtain a drawn fiber of a mixed spun fiber having a single fiber denier of 2 denier.

The drawn yarn of this mixed spun fiber was immersed in xylene at 60 ° C. for 10 minutes to extract substantially all of the polyethylene and the acid-modified polyethylene. As a result, a yarn consisting of an aggregate of ultrafine polyester fibers was obtained. . The properties of the mixed spun fibers and the physical properties of the ultrafine polyester fibers obtained therefrom are shown in Table 1.

[0036]

[Table 1]

According to the method of the present invention (Examples 1 to 5),
It can be seen that the spun and stretchable properties of the mixed spun fibers are good, and that the obtained mixed spun fibers can be formed into ultrafine polyester fibers having a sufficient length. On the other hand, when the amount of the polyester is smaller than the range of the present invention (Comparative Example 1), the spinning of the mixed spun fiber is difficult and the stretchability is very poor. That is, it is very difficult to form the mixed spun fiber itself. When the amount of the polyester is larger than the range of the present invention (Comparative Example 2) and when the amount of the acid-modified polyethylene is smaller than the range of the present invention (Comparative Example 3), it can be seen that ultrafine polyester fibers cannot be obtained. On the other hand, when the amount of the acid-modified polyethylene is larger than the range of the present invention (Comparative Example 4), spinning is extremely difficult, and the moldability of the mixed spun fiber is poor, which is not suitable.

Comparative Example 5 In an o-chlorofernol solution, 40 parts of a polyethylene terephthalate chip having an intrinsic viscosity of 0.64 measured at 35 ° C. and 60 parts of a high-pressure low-density polyethylene chip having a melt index of 30 were mixed with a chip blender. Was mixed using. Thereafter, spinning and drawing were performed in the same manner as in Example 1 to obtain a mixed spun fiber having a single fiber denier of 10 denier. In this case, spinning breakage occurred remarkably, and continuous spinning and stretching were impossible. The mixed spun fiber thus obtained was immersed in xylene at 60 ° C. for 60 minutes, and substantially all of the polyethylene was extracted. As a result, a microporous polyester fiber was obtained and an ultrafine polyester fiber was not obtained.

COMPARATIVE EXAMPLE 6 Polyethylene terephthalate chip 4 having an intrinsic viscosity of 0.64 measured at 35 ° C. in an o-chlorophenol solution
Using a chip blender, 5 parts of an acid-modified polyethylene having a melt index of 30 and 60 parts of a polypropylene having a melt index of 30 were prepared by copolymerizing 0 parts, methyl methacrylate and maleic anhydride at 4 mol% and 0.2 mol%, respectively. And mixed. The obtained mixture was spun and stretched in the same manner as in Example 1 to obtain a mixed spun fiber having a single fiber denier of 5 denier. This mixed spun fiber is
When the polypropylene and the acid-modified polyethylene were substantially completely extracted by immersion in toluene at 60 ° C. for 60 minutes, a fine fibrous material of polyester having a very short fiber length was obtained. This material could not be used to form a fabric.

Examples 6 to 7 As acid-modified polyethylene, acid-modified polyethylene having a melt index of 7 in which 4 mol% of ethyl acrylate was copolymerized (Example 6), and a melt index of 7 in which 5 mol% of ethyl methacrylate was copolymerized. Example 7 was carried out in the same manner as in Example 1 except that the acid-modified polyethylene (Example 7) was used. Table 2 shows the results.

[0041]

[Table 2]

In both cases where the acid-modified polyethylene was ethyl acrylate copolymerized polyethylene (Example 6) and where the acid-modified polyethylene was ethyl methacrylate copolymerized polyethylene (Example 7), the spinning drawability and dispersibility were good, and the resulting products were obtained. The mixed spun fibers were ultrafine polyester fibers having a sufficient length.

Example 8 The same procedure as in Example 1 was carried out except that polybutylene terephthalate having an intrinsic viscosity of 0.88 measured at 35 ° C. in an o-chlorophenol solution was used. As a result, the spinning drawability was excellent. (“Excellent” level), the dispersibility was good (O mark level), and the monofilament denier in the ultrafine polybutylene terephthalate fiber bundle after immersion in xylene at 60 ° C. for 10 minutes to elute all sea components was 0. 0.0005 to 0.005
de and the length of those single fibers is 40 to 120 mm
It was an extremely soft material suitable for use in artificial leather base fabrics and high-grade woven and knitted fabrics.

[0044]

The thickness of the ultrafine polyester fiber obtained by the method of the present invention described above is 0.1 denier or less, and most of the fiber has a thickness of 0.0001 to 0.0
It is in the range of 1 denier. Most of the ultrafine polyester fibers have a length in the range of 20 to 100 mm.

Such an ultrafine polyester fiber is used alone,
Alternatively, a fabric such as a nonwoven fabric, a woven fabric, or a knitted fabric can be used in combination with a fiber having a normal thickness (a single fiber denier is about 0.5 denier or more).

Such a fabric has a very soft touch and is preferably used as a base fabric for artificial leather.
Further, such a fabric having one or both sides brushed has a suede-like texture, and can be used for applications such as a high-grade artificial leather base cloth or a high-grade woven or knitted fabric.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification number Agency reference number FI Technical display location D02J 1/22 D02J 1/22 N // D06M 101: 16

Claims (1)

(57) [Claims] 1. A mixture comprising a polyester (A), a polyethylene (B) and an acid-modified polyolefin (C), which simultaneously satisfies the following and formulas, is melt-spun and drawn, and has a single fineness of 1 to 15 denier. process for producing a fiber, _{and, W a: W B = 30~60} : 70~40 W C / (W a + W B) = 0.01~0.30 _{[However, W a, W B, W} C is Weight of (A), (B) and (C) respectively contained in the above mixture] and a step of dissolving and removing polyethylene (B) and acid-modified polyolefin (C) from the obtained mixed spun fiber. The thickness is 0.
A method for producing an ultrafine polyester fiber of 1 denier or less.