JP2918715B2 - Split polyester composite fiber - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates generally relates to splittable polyester conjugate fiber alkali easily soluble component has a fiber cross-sectional shape of the form is divided into a plurality of alkali-soluble component, more particularly, The present invention relates to a splittable polyester composite fiber from which a polyester fiber having an ultrafine size can be easily and efficiently obtained by treating with an aqueous alkali solution.

[0002]

2. Description of the Related Art Conventionally, a splittable conjugate fiber in which an alkali-soluble component is divided into a plurality of alkali-insoluble (or non-) soluble components is obtained by removing the alkali-soluble component. It is widely known that a yarn consisting of ultrafine single-fiber fibers can be obtained, and that when the composite fiber is made into a fabric and then alkali-treated, it exhibits a silky feeling. In addition, the polyethylene terephthalate fiber of ultrafine single fineness obtained by such a method has excellent properties such as high melting point, high strength, high Young's modulus, good electrical properties, and chemical resistance. Woven and knitted goods, sports clothing,
It is expected to be used in filters, other clothing, and industrial fields.

[0003] In producing such splittable conjugate fibers, it is required that the process stability during yarn production is excellent, the dissolution rate difference between the alkali-soluble component and the alkali-soluble component is sufficiently large, It is desirable to have characteristics such as that the hardly soluble alkali component is uniformly separated when the soluble component is dissolved and removed (the hardly soluble alkali component does not adhere to each other during the treatment). It has been. However, a conjugate fiber that can satisfy all of these characteristics has not been proposed yet.

For example, Japanese Patent Publication No. 47-42847 and Japanese Patent Application Laid-Open No. 48-9021 disclose a method in which polyethylene terephthalate (hereinafter sometimes referred to as PET) and nylon-6 or polystyrene are formed into a composite fiber. Although a method of dissolving and removing polystyrene or nylon-6, which is hardly soluble in alkali, has been proposed, this method requires the use of a specific organic solvent or a strong acid in order to dissolve and remove the same, which reduces safety and cost. It was not satisfactory in terms of face.

[0005] Also, many splittable conjugate fibers using a polyester obtained by copolymerizing various third components as an easily soluble component have been proposed. For example, JP-A-54-138620 discloses a polyester obtained by copolymerizing a 5-sodium sulfoisophthalic acid component, and JP-A-58-54022 discloses a polyester having an average molecular weight of 90 to 50 in addition to a 5-sodium sulfoisophthalic acid component. JP-A-59-36775 discloses polyester obtained by copolymerizing 6000 glycol components.
Polyester added and copolymerized with a sodium sulfoisophthalic acid component and an isophthalic acid component and / or a polyoxyalkylene glycol component, JP-A-63-15952
No. 3 discloses a polyester obtained by copolymerizing a 5-sodium sulfoisophthalic acid component and an aliphatic dicarboxylic acid component and / or an alicyclic dicarboxylic acid.
No. 25 proposes a method using a 5-sodium sulfoisophthalic acid component, an isophthalic acid component and / or an aliphatic dicarboxylic acid component, and a polyester obtained by adding and copolymerizing a polyoxyalkylene glycol having an average molecular weight of 400 to 6000. I have. According to these methods, the difference in alkali dissolution rate could be made sufficiently large, and the alkali treatment time was extremely reduced. However,
Although the detailed reason is unknown, single fibers consisting of the alkali-insoluble component after the alkali treatment behave closely together as a group, or the composite fibers before the alkali treatment are easily peeled and divided by external force. It had problems. In other words, even when dissolved and divided by alkali treatment, a soft feel or peach-like feel derived from ultrafine fibers is not obtained, and the above-mentioned adhered portion is peeled off during use, resulting in a change in feel and an increase in surface reflection. However, it has a drawback such that lightening, spotting, and a feeling of discomfort are observed.

On the other hand, a number of splittable conjugate fibers using a polyester blended with a polyester and a non-reactive easily soluble component as an alkali easily soluble component have been proposed. For example, Japanese Patent Publication No. 47-47532 discloses a method of blending a polyoxyalkylene glycol having an average molecular weight of 10,000 or more, and Japanese Patent Publication No. 47-47533 discloses a method of blending 6 to 16% by weight of an anionic surfactant. Proposed. However, according to these methods, although the adhesion of the hardly soluble alkali component at the time of the dissolution division treatment generated by the method using the copolymerized polyester is not recognized, the ultrafine single fiber of 0.3 denier or less by the former method is not observed. In order to obtain the above, it is necessary to increase the alkali weight loss rate of the alkali-soluble component, and the addition amount of the polyoxyalkylene glycol is required to be 10% by weight or more. Disappears. On the other hand, in the latter method, since the thermal stability of the anionic surfactant is insufficient, there is a problem that at a melting temperature of the polyester close to 300 ° C., thermal decomposition occurs and the spinnability decreases, and the spinning is problematic. Conventionally, it has been difficult to simultaneously achieve the property and the dividing property by the alkali solution treatment.

As described above, in the splittable conjugate fiber, the splitting property suitable for obtaining an ultrafine fiber having a single fiber fineness of 0.3 denier or less after splitting and the yarn production stability suitable for operation production are simultaneously obtained. Satisfactory conjugate fibers have not heretofore been proposed.

[0008]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and an object of the present invention is to provide an ultrafine fiber having a single fiber fineness of 0.3 denier or less, which is excellent in operation production stability and easily. An object of the present invention is to provide a novel splittable polyester composite fiber that can be obtained.

[0009]

The present inventors have conducted intensive studies to achieve the above-mentioned object. As a result, the method using a polymer obtained by copolymerizing a 5-sodium sulfoisophthalic acid component as an alkali-soluble component is not suitable for reducing the amount of alkali. This is presumed to be due to the action of static electricity due to ions or to the formation of a high-viscosity solution when the soluble components are dissolved. I knew it would stick. Further, in the method of blending the polyester and the non-reactive polyoxyalkylene glycol, the solution viscosity of the portion in which the polyoxyalkylene glycol is dissolved becomes high, and diffusion of the alkali component becomes difficult, so that the alkali weight loss rate is not sufficiently improved. That is, since the solution viscosity increases when the polyoxyalkylene glycol component dispersed in the polyester is dissolved, the moving speed of the alkali component to the polyester component surface is extremely reduced, and the effect of improving the alkali weight loss speed is reduced. I knew that. As a result of further diligent studies based on this knowledge, the rate of alkali weight loss is extremely high if a compound having a molecular weight high enough to allow fine streak dispersion during spinning and decomposing during alkali treatment and not increasing the solution viscosity is blended. The present inventors have found that they have become larger, and have reached the present invention.

That is, according to the present invention, alkali-soluble
Soluble component A (hereinafter sometimes referred to as component A or A component)
) By the poorly soluble alkali component B (hereinafter component B or
Component B) , wherein the component B is a polyester (I) having an ethylene terephthalate unit as a main repeating unit, and the component a is a polyether ester composed of a dicarboxylic acid component and a polyoxyalkylene glycol component polyethylene
Splittable polyester conjugate fiber which is a polyethylene <br/> ester compositions formulated 3 wt% or more ester (II), is provided.

In the present invention, the component A which divides the component B into a plurality of components is a polyetherester, which is a polymer of a dicarboxylic acid component and a polyoxyalkylene glycol, in an amount of 3% by weight or more based on the polyester (II). It is important to use a polyester composition blended in an amount of preferably 3 to 10% by weight, more preferably 4 to 8% by weight.

The dicarboxylic acid component of the polyetherester preferably used includes aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid, diphenyldicarboxylic acid, diphenoxyethanedicarboxylic acid, adipic acid, sebacic acid, and the like. And aliphatic and alicyclic dicarboxylic acids such as 2,4-cyclohexanedicarboxylic acid. On the other hand, preferably used polyoxyalkylene glycols include polyoxyethylene glycol, polyoxypropylene glycol, polyoxybutylene glycol, polyoxypentylene glycol, polyoxyhexylene glycol, and random or block copolymers thereof. Among them, polyethylene glycol is preferred. Further, if the molecular weight of the polyoxyalkylene glycol is too small or too large, the effect of increasing the rate of alkali weight loss is reduced, so it is desirable that the molecular weight is 1,000 to 50,000, preferably 3,000 to 20,000.

On the other hand, if the molecular weight of the polyetherester composed of the above components is too small, the polyetherester component will not disperse streaks during melt spinning, and the alkali weight loss rate will not sufficiently increase. Is preferably reduced to 10,000 to 80,000, and more preferably 4 to 50 dicarboxylic acid components are copolymerized per molecule of the polyetherester.

In order to produce such a polyetherester, a conventionally known method may be employed as it is.
It can be easily obtained by reacting the acid anhydride or acid chloride of the dicarboxylic acid with the polyoxyalkylene glycol. At this time, a small amount of low molecular weight glycol such as ethylene glycol or tetramethylene glycol may be copolymerized within a range not to impair the purpose of the present application.

It is important to incorporate the above-mentioned polyetherester in an amount of 3% by weight or more based on the polyester (II). If the amount is less than 3% by weight, a sufficiently high alkali weight loss rate cannot be obtained. Production of ultrafine fibers of 0.3 denier or less is also difficult, which is not preferable. In addition,
When the compounding amount is large, thread breakage is liable to occur due to the decomposition gas, which is a thermal decomposition product, and the spinnability tends to deteriorate. Therefore, the content is preferably 10% by weight or less.

On the other hand, the polyester (II) used for the component A is not particularly limited, but the polyester used for the component B described below is preferable in terms of good spinning properties during melt spinning and good handling of the conjugate fiber. (I)
The same is preferred.

Polyester (I) used for component B
Is a polyethylene terephthalate-based polyester having an ethylene terephthalate unit as a main repeating unit, and may be a polyester in which a part of a terephthalic acid component is replaced by another difunctional carboxylic acid component, and / or
Alternatively, it may be a polyester in which a part of the ethylene glycol component is replaced by another diol component.

The bifunctional carboxylic acids other than terephthalic acid used herein include, for example, isophthalic acid, naphthalene dicarboxylic acid, diphenyl dicarboxylic acid, diphenoxyethane dicarboxylic acid, adipic acid, sebacic acid,
Aromatic, aliphatic and alicyclic bifunctional carboxylic acids such as 1,4-cyclohexanedicarboxylic acid can be mentioned. Examples of diol compounds other than ethylene glycol include aliphatic, alicyclic and aromatic compounds such as tetramethylene glycol, hexamethylene glycol, cyclohexane-1,4-dimethanol, neopentyl glycol, bisphenol A and bisphenol S. Diol compounds can be mentioned.

In the present invention, a split fiber comprising a poorly soluble alkali component is obtained by the difference in the alkali weight loss rate between the component A and the component B. The larger the difference in solubility is, the more desirable. Is 10 of B component
It is desirably at least 20 times, preferably at least 20 times.
Accordingly, the polyester (I) constituting the component B is particularly preferably polyethylene terephthalate.

It is also desirable to add an anionic surfactant in order to increase the alkali weight loss rate of the component A. At that time, if the blending amount is too large, the spinning properties tend to decrease, while if the blending amount is too small, the improvement effect is not recognized, so the anionic surfactant is
0.2 to 2% by weight, especially 0.4 to 2% by weight based on the component A
It is preferable to add 1% by weight.

Next, the above-mentioned composite shape of the alkali-soluble component A and the alkali-poorly soluble component B and the cross-sectional shape of each component show the shape obtained by dividing the component B into a plurality by the component A. Is arbitrary and some examples are shown in FIGS. 1 (a) to 1 (i).

In FIG. 1, A is an alkali-soluble component (A component), and B is a poorly-soluble alkali component (B component). In (a)-(c), component B is divided into 16 by component A. (D) is a sea-island type splittable conjugate fiber in which A is the sea and B is the island, and the component B is divided into 26 by the component A. (E) to (f) have a flat cross-sectional shape, and (g) to (i) have cross-sectional shapes in which the outer peripheral portions of (a) to (c) are covered with the component A, respectively. . The splittable conjugate fiber having such a cross-sectional shape is
By performing an alkali treatment after forming the cloth, it is possible to form a fine fiber and to have a space between the fibers, so that it is suitable for obtaining a cloth having a bulky and soft feel.

The composite ratio of component A and component B in the splittable polyester composite fiber is such that the more component A, the easier the splitting by alkali treatment, but if too large, the fiber properties of the composite fiber are reduced and the post-process Passability deteriorates, and cost becomes disadvantageous. From such a viewpoint, the weight ratio of component A: component B is preferably in the range of 80:20 to 2:98,
The range of 60:40 to 5:95 is more preferable.

In the splittable polyester composite fiber of the present invention, the effect obtained when the constituent unit comprising the component B is set to 0.3 denier or less and the number of the constituent units is set to 16 or more, especially 24 or more. Remarkable and preferable.

To produce the splittable polyester composite fiber of the present invention described above, any conventionally known composite spinneret and composite spinning apparatus can be used, and any spinning conditions can be adopted without any trouble. For example, 500-2500m /
Melt spinning, stretching and heat treatment at a speed of 150 minutes
A method in which melt spinning is performed at a speed of 0 to 5000 m / min, and stretching and false twisting are performed simultaneously or successively, a method in which melt spinning is performed at a high speed of 5000 m / min or more, and a drawing step is omitted depending on the application. Can be adopted. Further, the obtained fiber or a woven or knitted fabric produced from this fiber may be heat-treated at a temperature of 100 ° C. or more to improve the stability of the structure, or may further be used together with a relaxation heat treatment if necessary. .

[0026]

The polyether ester blended in the component A of the present invention, like the polyoxyalkylene glycol, exists in a dispersed state instead of being dissolved in the polyester (II). In addition, since its molecular weight is as high as 10,000 or more, when it is formed into a composite fiber, it is dispersed in a streak shape in the fiber axis direction. As a result, an effect equivalent to an increase in the rate of alkali weight loss by blending polyoxyalkylene glycol can be obtained.

Further, in addition to the above effects, the polyetherester used in the present invention is different from the conventionally used polyoxyalkylene glycol in that the polyetherester is easily hydrolyzed at the time of alkali weight reduction treatment. It has the feature that the viscosity of the elution solution does not increase. As a result, it is presumed that the renewal of the alkali solution on the fiber surface or the diffusion of the alkali component to the fiber surface becomes easy, and the alkali weight loss rate is kept high without decreasing.

Therefore, according to the present invention having such characteristics, a good alkali weight reduction rate can be maintained even if the amount of the third component present in the component A is reduced, so that the process stability at the time of yarn production is improved. Thus, extremely remarkable effects such as easy production of polyester fibers of ultrafine size can be obtained without impairment, and its industrial significance is extremely large.

[0029]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the present invention is limited thereto.

[0030]

Example 1 Polyethylene terephthalate having an intrinsic viscosity of 0.63 (polyether ester and polyether) containing 6% by weight of a polyetherester compound shown in Table 1 as Component A
1) using a polyethylene terephthalate having an intrinsic viscosity of 0.64 as the component B and compound spinning and stretching according to a conventional method.
The hollow multi-layer bonded type composite fiber shown in FIG.
Layer, composite ratio 50/50, 75 denier / 20 filament).

A plain fabric is formed using the obtained composite fiber,
The alkali weight reduction treatment was performed in an aqueous sodium hydroxide solution (concentration: 30 g / liter) at the boiling temperature. Table 1 shows the weight loss rates required for the division.

[0032]

[Table 1]

As is evident from the above table, polyester (polyether) blended with the polyetherester referred to in the present invention.
Composition of polyester ester and polyethylene terephthalate
No. 1 ) as an alkali-soluble component. 1
In Nos. To 4, it can be seen that the alkali weight loss proceeds rapidly and the hardly soluble alkali component B (polyethylene terephthalate) can be divided into ultrafine fibers without decomposing much (that is, at a stage where the weight loss rate is low).

On the other hand, it can be seen that in No. 5 containing polyethylene glycol, an alkali weight loss rate of 75% was required, and more than half of the hardly soluble alkali component had to be dissolved and removed.

[0035]

Example 2 A composite fiber yarn of 75 denier / 20 filaments was obtained in the same manner as in Experiment No. 2 of Example 1 except that the amount of the polyetherester blended in the component A was changed. Table 2 shows the result of alkali treatment of the same plain weave.

[0036]

[Table 2]

As is clear from the above table, when the blending amount of the polyetherester is small as in Experiment No. 6, the alkali weight loss required for dividing the component B becomes extremely large. On the other hand, when the blending amount is large, thread breakage occurs, and the spinnability is slightly lowered.

[0038]

Example 3 In Experiment No. 4 of Example 1, component A
Table 3 shows the results obtained in the same manner except that sodium alkylsulfonate having an alkyl group having 8 to 20 carbon atoms and having an average carbon number of 14 is blended in the amount shown in Table 3.

[0039]

[Table 3]

As is clear from the above table, when the anionic surfactant is blended in the component A, the alkali weight loss required for dividing the component B is close to 50%, and the alkali weight loss of the component B itself is too small. You can see that it has not happened.

[Brief description of the drawings]

FIGS. 1A to 1I are cross-sectional model diagrams showing examples of a splittable polyester conjugate fiber of the present invention.

[Explanation of symbols]

A polyether ester polyester (II)
Formulated for poly ester composition B Polyester (I)

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hironori Yamada 77, Kitayoshida-cho, Matsuyama-shi, Ehime Teijin Co., Ltd. Matsuyama Works (72) Inventor Takeshi Fujita 114-9, Ono, Hirono-cho, Uji-shi, Kyoto (56 References JP-A-58-54022 (JP, A) JP-A-62-78213 (JP, A) JP-B-47-47533 (JP, B1) (58) Fields investigated (Int. Cl. ⁶ , DB Name) D01F 8/14 D06M 11/38

Claims (4)

(57) [Claims] 1. A alkali by alkaline easily soluble component A
In a splittable polyester composite fiber having a fiber cross-sectional shape in which the hardly soluble component B is split into a plurality of pieces, the component B
Is a polyester (I) having an ethylene terephthalate unit as a main repeating unit, and the component A is a polyester (II) comprising a polyether ester comprising a dicarboxylic acid component and a polyoxyalkylene glycol component.
Splittable polyester conjugate fiber which is a polyester composition formulated 3 wt% or more. 2. The compounding amount of the polyetherester is high.
2. The split-type polyester according to claim 1, which is 10% by weight.
Composite fiber. 3. The polyetherester is a polyester
(II) A method wherein the particles are dispersed in a streak shape along the fiber axis direction.
2. The splittable polyester composite fiber according to 1. 4. The method according to claim 1, wherein component A is
And 0.2 to 2% by weight of an anionic surfactant is blended.
The splittable polyester conjugate fiber according to claim 1.