KR960015090B1 - Extractive Composite Fiber - Google Patents

Abstract

None.

Description

Extractive Composite Fiber

1 is a relationship between the amount of polyethylene glycol and a metal sulfonate-containing ester showing a range satisfying the present invention.

The present invention relates to an extractable composite fiber which is excellent in solubility in alkali, hot water, and the like, which is complex, so that the extractable copolyester can be easily dissolved and removed with hot water or the like to be made of an ultrafine fiber and a special release section yarn.

As a method of manufacturing a conventional microfiber, the direct spinning method is difficult in handling at the time of spinning and at the fine quality of the microfiber and in the post-processing, there is a limit in the current technical stage. Therefore, a means for dissolving, removing, or swelling and dividing at least a part of a composite fiber of different components (cross-sectional shape is island-in-sea type, blend type, split type, etc.) is known.

In general, a composite fiber is a multicomponent system such as a microfiber-generating composite fiber which obtains an ultrafine fiber by dissolving and removing one of its components, more specifically, an island-in-sea composite fiber, a mixed spun composite fiber, and a peeled-off composite fiber. By the removal of the composite fiber and one component refers to a composite fiber to form each deformation cross-section, a composite fiber that gives a special sublime property by removing one component from the knitted fabric after the set.

The composite fiber produced by the composite spinning of the heterogeneous component is roughly divided into the split type composite fiber and the extractable composite fiber according to the presence or absence of the heterogeneous component. Split-type composite fibers are microfibers of heterogeneous components. The splitting method is known as a forced splitting method by mechanical treatment such as flammable and a chemical splitting method by dissolving or swelling at least one component by chemical treatment. .

Extractive composite fibers dissolve and remove the soluble polymer component from the solvent, and microfiberize only the poorly soluble polymer component. Polymers usable as usable components include modified polyesters, polystyrenes, polyethylenes, etc. Among these, polystyrenes and polyethylenes can be dissolved by organic solvents, but solvents and facilities are expensive, and there are risks in working. Alkali-soluble modified polyesters are suitable.

In extractable composite fibers, polyamide and polyester are mainly used as poorly soluble polymers. In case of using polyamide for poorly soluble portion, it is necessary to extract with alkaline hot water to dissolve and remove polyester. However, since the extraction speed is slow, it is a problem for productivity. Sodium sulfoiso It is modified and used with the same material as phthalic acid.

When polyester is used for the soluble portion and ordinary polyester or modified polyester is used for the poorly soluble portion, when the elution rate of the modified polyester, which is the soluble portion during the production, weaving and knitting of the nonwoven fabric is low, the separation of the poorly soluble portion does not occur. Soluble parts are also damaged, resulting in a sharp decrease in physical properties. Even when the copolyester modified with 5-sodium sulfoisophthalic acid is used as one component of the composite fiber, the existing polyester, which is another component, is infringed, and thus the mechanical strength of the final product becomes weak.

In Japanese Patent Publication No. 58-39926, water-soluble polyesters are dissolved and removed during stretching from a composite fiber prepared by spinning a blend containing 20 to 60 mol% of a water-soluble polyester of 5-sodium sulfoisophthalic acid copolymer. Has been proposed a method for producing ultrafine fibers. However, when a large amount of 5-sodium sulfoisophthalic acid is added in this way, it is difficult to obtain a sufficient degree of polymerization due to foaming and thickening in the polymerization reaction, and it is not satisfactory in sacrificial properties.

In addition, many water-soluble polyesters have been proposed for use in adhesives, sizing agents, paints, and the like (for example, Japanese Patent Application Laid-Open Nos. 47-40873, 57-26309, and 60-1334). It was unsuitable as desired extractable polyester.

In a series of patents (Japanese Patent Publication Nos. 63-152624, 63-1665516, 63-273634, etc.) filed recently by Toray Industries, Japan, the content of isophthalic acid and 5-sodium sulfoisophthalic acid exceeds 30 mol%. However, if this happens, the melting point of the polymer is lost and only the softening point becomes amorphous, which causes a lot of problems in the ritual stage, such as making sand formation difficult during spinning. In addition, the physical properties of the formed yarns become weak, which leads to problems in post-processing. In addition, since the third component is used in an excessive amount, the manufacturing cost is increased and it is not economical.

Accordingly, the present invention is to provide a composite fiber suitable for the production of ultrafine fibers having excellent final mechanical strength by incorporating an extractable copolyester which is easily eluted in alkaline hot water or the like, in view of various problems of the popular technology.

According to the present invention for solving the above problems, an extractable composite fiber composed of a water-soluble extractable polyester component and a poorly water-soluble fiber-forming polymer, wherein the extractable polyaryl ester component mainly comprises an ester unit of ethylene terephthalic acid. The number average molecular weight (A) in the polyester which was functional and the A sulf% copolymerized metal sulfonate-containing ester units A) and B are prepared by modifying by adding B% by weight of polyalkylene glycols of 8,000 or more, wherein A and B satisfy the following formulas (1) and (2), and are 95% in a 5% aqueous sodium hydroxide solution for 10 minutes. Provided is an extract-type composite fiber characterized in that it has a solubility of 50 times higher than the general polyester solubility at the time of dissolution.

0.24B + 3≤A≤-0.05B + 15 (1)

A≤-2.05B + 71.75 (2)

In the composite fiber of the present invention, the extractable polyester component eluted and removed by alkaline treatment of the composite fiber is composed mainly of terephthalic acid and ethylene glycol, and is a metal sulfonate-containing ester unit and a polyalkyl having a number average molecular weight of 8,000 or more. The copolymer in which the len glycol is copolymerized in a specific amount is used. In other words, the extractable foryl ester used in the present invention has a number average molecular weight (A) in a polyester in which an ester unit of ethylene terephthalic acid is the main component and a metal sulfonate-containing ester unit is A mol% copolymerized. ) Is modified by adding B% by weight of 8,000 or more polyalkylene glycols.

As the metal sulfonate-containing ester unit copolymerized to the polyester in the present invention, an acid ethylene glycol derivative which is stable in an aqueous alkali solution and advantageous in radioactivity and post-processing, in particular, or 5-sodium sulfoisophthalate is preferable.

Polyalkylene glycols added as a modifying component to increase the usability is preferably polyethylene glycol, polypropylene glycol, polybutylene glycol, and the like. In order to rapidly increase the solubility in an aqueous alkali solution, polyalkyl having a number average molecular weight of 8,000 or more is used. It is necessary to include alkylene glycol as one component. Even better than 10,000 is good.

In general, the sulfonate in the metal sulfonate-containing ester unit is a hydrophilic group, thereby assisting hydrolysis by water, and the hydrolysis rate is significantly different depending on the sulfonate content.

For example, when dissolution test is carried out in a 1N sodium hydroxide aqueous solution, a co-polyester containing 2.5 mol% of a metal sulfonate unit and a polyester containing 5 mol%, the dissolution rate is 2.5 mol% when compared at the same time. It is only about 1/5 of 5 mol%. In addition, it is relatively poor in dissolving stones 5 times compared to the general PET. Therefore, the content of metal sulfonate containing ester units should be at least 3 mol% or more in the polymer backbone.

On the other hand, when the content of the metal sulfonate-containing ester unit exceeds 15 mol%, the solubility is excellent, but the resulting polymer is eluted even in cold water, which makes it difficult to handle and chip breakage occurs during chip cutting after polymerization. Is uneven, which causes malfunctions such as feeding failure during spinning. In addition, difficulties in the production of polymers arise due to the generation of viscous bubbles during the polymerization, an increase in viscosity, and the like.

The higher the amount of the polyalkylene glycol, the higher the elution rate. However, if the amount exceeds 35% by weight, the heat resistance is insufficient, the melt viscosity of the polymer is sharply dropped, and the radioactivity is poor, and the polymerization is difficult. Therefore, the amount of polyalkylene glycol added is preferably 30% by weight or less.

On the other hand, the content of the metal sulfonate-containing ester unit and the amount of the polyalkylene glycol added are correlated, so that the content more than necessary is poor in operability and uneconomical.

Therefore, the content of the two compounds is preferably adjusted within the range to satisfy the above formula (1) and (2) at the same time. The hatched portion in Fig. 1 is a region that satisfies the above formulas (1) and (2) simultaneously.

Next, a synthesis example of the extractable polymer will be described. The extractable polyester is known by using known methods using, for example, terephthalic acid, ethylene glycol, 5-sodiumsulfoisophthalana or 5-sodiumsulfoisophthalate, polyalkylene glycol having a number average molecular weight of 8,00-20,000. It can manufacture by superposing | polymerizing.

In the case of direct polycondensation, for example, the point of incorporation of each of the above substances can be added simultaneously. Terephthalic acid and ethylene glycol can be added at the same time, and 5-sodium sulfoisophthalic acid whose terminal is dicarboxylic acid is the initial esterification reaction. In the case of 5-sodium sulfoisophthalate, for example, 5-sodium sulfoisophthalic acid hydroxyethyl ester, it is preferable to add at the end of the esterification or at the beginning of the polymerization. In the polycondensation, known compounds such as alkali metal compounds, alkaline earth metal compounds, cobalt, antimony, titanium, manganese, zinc, phosphorus and the like can be employed as reaction catalysts and additives.

For example, the preparation of extractable polyester by direct polycondensation is described according to the reaction process sequence. At least 1.2 mol% of ethylene glycol is added to the esterification reaction tube with respect to terephthalic acid and its acid component to about 1.7 kg / cm. _2, the water generated by the reaction is collected while stirring at a pressure of about 250 ° C and a temperature of about 250 ° C, and when the amount of the spilled water reaches 90 to 95% of the theoretical value, the esterification reaction is stopped and the resulting oligomer is transferred to the polymerization tube. Hydroxyethyl ester of 5-sodium sulfoisophthalic acid and polyalkylene oxide were added to the transferred esterification product, and a polymerization catalyst and a thermal stabilizer were added. Glycol can flow out of the reaction system to obtain an extractable polyester.

Thus, the extractable polyester which selected and comprised the metal sulfonate containing ester unit by water-soluble component, and polyalkylene glycol as a crystallization support or dissolution promoting component, satisfy | fills the correlation of Formula (1) and (2) is hot water. And it exhibits a property that is quickly dissolved and extracted from weak alkali, maintains heat resistance even at high temperatures and does not lower the melt viscosity.

Such extractable polyesters may, for example, comprise polyethylene terephthalate (regular PET) in a constant composite ratio. Such a composite fiber can be prepared by extractable microfiber by treating with alkaline water. In this case, the extractable polyester has a solubility at 95 ° C. in a 5% aqueous sodium hydroxide solution for 10 minutes and is 50 times higher than that of general PET. The general polyester, the soluble portion, is not violated and the mechanical strength of the final microfiber is excellent.

The present invention will be described in detail with reference to the following Examples. However, the present invention is not limited to the examples. In addition, in a following example and a comparative example, a part refers to a weight part. In addition, in the following Example and the comparative example, solubility and a dissolution ratio are the result of having performed by the following method.

1) Solubility

Each polymer was made into a film having a thickness of about 160 ± 5 μm using a hot press, dissolved in 2.5% sodium hydroxide solution and 5% sodium hydroxide solution at about 95 ° C. for 10 minutes, and washed three times with excess distilled water. After drying for 10 hours in a 50 ℃ vacuum oven, the weight was measured to determine the solubility based on the following formula.

2) dissolution ratio

The solubility measured by the above solubility measuring method divided by the solubility with general PET is taken as the dissolution ratio.

Example 1

100 parts of dimethyl terephthalate, 7.6 parts of 5-sodium sulfoisophthalate (DMIS), 40 parts of ethylene glycol and 0.06 parts of zinc acetate were placed in an autoclave and subjected to transesterification with distillation of methanol produced at 150 to 230 ° C. . 5 parts of polyethylene glycol (PEG), 0.067 parts of antimony trioxide, and 0.02 parts of phosphoric acid were added thereto, followed by reaction for about 3 hours in a vacuum of about 1 mmHg or less while raising the temperature from 230 ° C to 280 ° C. . The solubility, dissolution ratio and cutting properties of the polymers obtained in Table 1 are shown.

EXAMPLES 2-3, COMPARATIVE EXAMPLES 1-2

The same procedure as in Example 1 was carried out except that the molecular weight of polyethylene glycol was changed as in Table 1.

Examples 4 to 8 and Comparative Examples 3 to 5

The same procedure as in Example 1 was carried out except that the polyethylene glycol content and the metal sulfonate-containing ester unit content were changed as shown in Table 1.

* Outside the conditions of the present invention

Cutting property: ○… No chip breaking during cutting

? Some chips break when cutting

×… Many chips break during cutting

From the above Table 1, the extractable polyester of the embodiment according to the present invention has a solubility of 50% or more than that of general PET at 95 ° C. for 10 minutes in a 5% sodium hydroxide aqueous solution. It can be seen that it is possible to manufacture the microfiber with excellent mechanical strength by quickly eluting removal without giving.

Claims (2)

An extractable composite fiber composed of a soluble extractable polyester component and a poorly soluble fiber-forming polymer, wherein the extractable polyester component comprises an ester unit of ethylene terephthalic acid as a main function and a metal sulfonate-containing ester unit Number average molecular weight (Amol% copolymerized polyester) A) and B satisfy the following formulas (1) and (2), wherein the extractable polyester component is added to 5% aqueous sodium hydroxide solution. Extraction type composite fiber, characterized in that having a solubility 50 times higher than the general polyester solubility when eluted at ℃, 10 minutes. 0.24 + 3≤A≤-0.05B + 15 (1) A≤-2.05B + 71.75 (2) The extractable composite fiber according to claim 1, wherein the content of polyalkylene glycols having a molecular weight of 8,000 or more is 35% by weight or less.