JPS63159525A - Production of conjugate fiber having water-soluble component - Google Patents

Abstract

PURPOSE:To obtain the titled fibers, capable of removing water-soluble components with hot water and useful as ultrafine fibers, etc., by melt spinning a copolymer containing terephthalic acid as a principal component and 5-sodium sulfoisophthalate, polyalkylene glycol, etc., as one component, drawing the resultant fibers and heat- treating the drawn fibers. CONSTITUTION:A copolyester containing terephthalic acid as a principal acid compo nent and 5-sodium sulfoisophthalate in an amount of 5-15mol% based on the total acid component, isophthalic acid and/or 3-20C aliphatic dicarboxylic acid in an am ount of 5-50mol% based on the total acid component and a polyacid anhydride from a 3-20C aliphatic dicarboxylic acid and/or polyalkylene glycol (derivative) having 400-6,000 average molecular weight and/or polyalkylene glycol (derivative) having 400-6,000 average molecular weight in an amount of 0-20wt.% based on the total polymer as copolymerization components is used as one component and subjected to melt conjugate spinning to provide fibers, which are drawn and heat-treated at a temperature of >=20 deg.C lower than the softening temperature [(Ts) deg.C] of the copoly mer without causing mutual melt sticking of the conjugate fibers to afford the aimed conjugate fibers.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention uses a water-soluble copolymerized polyester as one component,
The present invention relates to an I-manufacturing method for composite fibers that can easily produce ultrafine fibers, special irregular cross-section yarns, etc. by treatment with hot water, hot water, or even dilute alkaline water (hereinafter referred to as hot water, etc.).

[Conventional technology] Directly producing ultra-fine fibers using the melt-spinning method has many problems, such as operability during spinning and drawing and ease of handling during higher processing steps. It is considered difficult to directly produce ultrafine fibers with good quality by melt spinning.

For this reason, ultra-fine fibers can be made by dissolving and removing one component, at least a part of which occupies the surface of the i-fiber, by making the different components into a composite am with a cross-sectional shape such as a sea-island type, a blend type, or a splittable multilayer type. Alternatively, it is produced by a method of swelling and dividing. At this time, chemicals are used to dissolve and remove or swell and divide. For example, trichlorethylene is used to dissolve and remove polystyrene. These chemicals are dangerous to handle and require special equipment to dissolve and remove them.

For this reason, single component removal methods using chemicals still have problems in terms of worker safety and health, equipment, and wastewater treatment.

On the other hand, in Japanese Patent Publication No. 58-39926, 20 to 60
A method is disclosed in which a water-soluble polyester obtained by copolymerizing 5-sulfoisophthalic acid sodium salt in an amount of mol % is blend-spun and then dissolved and removed during stretching. However, when such a large amount of 5-sulfoisophthalic acid sodium salt is added, it is difficult to obtain a sufficient degree of polymerization due to foaming and thickening effects during the polycondensation reaction, and the spinning properties during composite spinning are also affected. It wasn't satisfying. Moreover, the water-soluble polyester used here has the problem of not being able to use water for discharging the molten polymer after the polymerization reaction and cooling it when forming into a string because it dissolves even in cold water. However, since it is deformed by moisture in the air, it is difficult to handle during post-processing.

Therefore, we improved this water-soluble copolyester and
15 mol% of 5-sodium sulfoinphthalate and 5-
It was previously proposed to use a copolymerized polyester containing 40 mol% of isophthalic acid and/or aliphatic dicarboxylic acid, with the main acid component being terephthalic acid, and to use this copolymerized polyester as at least one component of the composite fiber. .

However, although the water-soluble components of this composite fiber exhibit good hot water solubility in the undrawn yarn stage, when the water-insoluble components are stretched to crystallize their molecular chains in order to improve their physical properties. In some cases, the water-soluble components were unable to fully exhibit their original hot water solubility.

[Problems to be Solved by the Invention] Therefore, the present invention provides that the water-insoluble components in the composite fiber exhibit good physical properties such as crystal orientation, and the water-soluble components have sufficiently high hot water solubility. The present invention provides a manufacturing method for obtaining a composite fiber exhibiting the following properties. In other words, water-soluble components can be easily dissolved and removed using hot water, etc., and furthermore, V with excellent physical properties can be obtained after the water-soluble components are removed.
The main purpose of this invention is to provide a method for producing composite fibers that can obtain fibers.

[Means for Solving the Problems] To achieve this objective, the present invention provides the following copolymerization components: A: 5-15 mol% of 5-sodium sulfoisophthalic acid based on the total acid component; B: Total acid. Isophthalic acid and/or aliphatic dicarboxylic acid having 3 to 20 carbon atoms in an amount of 5 to 50 mol% based on the components, and C: O to 2 Qwt% based on the total polymer having 3 to 2 carbon atoms.
polyanhydrides from aliphatic dicarboxylic acids of 0 and/or
or by melt-composite spinning a copolyester containing a polyalkylene glycol or a derivative thereof having an average molecular weight of 400 to 6,000 and whose main acid component is terephthalic acid as at least one component of the composite fiber, and then drawing it. , in the method for producing a composite fiber having a water-soluble component, after the stretching, the softened portion U (T3° C.) of the copolyester
A method for producing composite m-fibers having a water-soluble component, which is heat-treated at a temperature 20 degrees lower [(TS-20>''01 or higher) and at a temperature that does not cause fusion of the composite fibers.

The method of the present invention includes at least a specific water-soluble copolyester obtained by copolymerizing polyethylene terephthalate with at least 5-sodium sulfoisophthalic acid, isophthalic acid, and/or C3-20 aliphatic dicarboxylic acid in a specific ratio. When manufacturing the composite fiber used as one component, it is characterized by heat treatment at a specific temperature after crystal orientation.

The copolymerized polyester of the composite fiber targeted by the present invention is
The above-mentioned A-C components are included as copolymerization components.

Of these, the A component, 5-sodium sulfoisophthalic acid, is 5 to 15 mol%, preferably 8 to 12% by mole, based on the total acid components.
．． 5 mol% is good.

If it is less than 5 mol %, it is difficult to sufficiently dissolve and remove the polymer with hot water. On the other hand, if it exceeds 15 mol%, it will be eluted even with cold water, so cooling of the manufactured polymer,
It becomes difficult to handle during melt spinning and stretching, making it unsuitable for industrial production.

In general, along with the above-mentioned 5-sodium sulfoisophthalic acid, the B component: 5 to 50 mol% of isophthalic acid and/or C3 to 20 aliphatic dicarboxylic acid (hereinafter referred to as isophthalic acid, etc.) may also be copolymerized. is necessary. Preferably, it is 5 to 40 mol%. Here, as the aliphatic dicarboxylic acid, adipic acid, sebacic acid, dodecanniic acid, azelaic acid, etc. are used. If the above-mentioned isophthalic acid and the like are less than 5 mol %, the solubility in hot water decreases, and flaky insoluble matter remains when dissolved in hot water. On the other hand, if there is too much of the above-mentioned isophthalic acid, etc., the softening point of the obtained polymer will be too low, and drying before melt spinning may not be carried out sufficiently, and the wound yarn during spinning or drawing may be mixed between single filaments or Fusion occurs between yarns.

This copolyester has a main acid component (i.e.
About 50% or more of the total acid components) is terephthalic acid. If the proportion of terephthalic acid is too small, the softening point of the polymer will be too low, causing problems with chip drying before melt spinning and with yarn wound during spinning and stretching.

In addition to the above-mentioned essential copolymerization components, this copolyester also contains the C component: a polyacid anhydride from an aliphatic dicarboxylic acid having 3 to 20 carbon atoms, and/or a polyester having an average molecular weight of 400 to 6000. Alkylene glycol or its derivatives may be copolymerized in an amount of, for example, 20 wt % or less, as long as the excellent properties such as insolubility in cold water and easy solubility in hot water are not impaired. When the polyalkylene glycols mentioned above are copolymerized, they can be made solubilized in dilute alkaline water without impairing the properties of being insoluble in cold water and soluble in hot water/warm water.

When this copolymerized polyester is dissolved in hot water, warm water, or even dilute alkaline water, it can be made into a transparent liquid or a liquid in an emulsified finely dispersed state. Can be dissolved without leaving any residue.

In the composite fiber targeted by the method of the present invention, as the other composite component used together with the above-mentioned water-soluble copolyester, a conventional melt-spun water-insoluble polymer can be used. The water-insoluble polymer is not particularly limited as long as it has fiber-forming properties and is insoluble in water, and its melting point and softening point are approximately the same or higher than those of the copolyester. Available for use.

For example, polyamides such as nylon 4, nylon 6, nylon 7, nylon 11, nylon 12, and nylon 66, polyesters such as polyethylene terephthalate and polybutylene terephthalate, polyolefins such as polyethylene and polypropylene, and water-insoluble Copolymers, modified products, and the like are preferably used. This other composite component is not limited to one component, but may be two or more components.

The composite form of the composite fiber according to the present invention is an ultrafine fiber generation type composite form in which ultrafine fibers are obtained by removing one component of the composite fiber, specifically a sea-island type composite type, a mixed spinning composite type, and a peel-splitting type composite type. A multi-component composite form, such as a composite form that can form various deformed cross sections by removing one component, or a composite form that can create special bulkiness and elasticity by removing one component from the knitted fabric after setting. It can take a complex form that can be given. In order to sufficiently dissolve and remove the copolymerized polyester, it is preferable that at least a portion of the fiber surface be made into a composite form in which the copolymerized polyester occupies.

Such composite fibers can be produced, for example, by a spinning method in which the composite fiber is melt-spun, once wound into a package, and then stretched, a spinning method in which spinning and stretching are performed continuously, or a spinning method in which the fiber is spun at high speed and mechanically stretched. It is possible to spin the yarn by winding it up as it is and then stretching it at a low magnification. In other words, this composite fiber is made by melt-spinning, cooling, oiling, and stretching to crystallize the water-insoluble components! ! ! However, in the method of the present invention, it is important to perform heat treatment at a specific temperature after this stretching.

This heat treatment may be performed at any time after the stretching point during stretching and before the copolymerized polyester component removal treatment using hot water or the like. contact with a heating roller, or
This can be done by passing through heated steam or heated air. In addition, after stretching, once rolled up,
Heat treatment may be performed again. Furthermore, this heat treatment may be performed on the fibers after they are made into textile products such as fabrics, as long as they are before treatment with hot water or the like. In this case, for example, i
An example of this method is to heat the product by placing it in an oven or the like.

Note that the softening temperature (T, ) of the copolymerized polyester is a value measured by the following method.

Softening point: Heat treatment of polymer chip (70°C x 3hr)
Shun, measured with a penetrometer. Temperature increase rate 10℃/
The softening point was defined as the temperature at which a chip with a thickness of 3 mm deformed by 0.1 in minutes.

This heat treatment is performed at the softening temperature (T, ) of the copolymerized polyester.
The temperature must be at least 20 degrees lower than that of the conjugate fibers, and the temperature must be at least 20 degrees Celsius at which conjugate fibers do not fuse together (that is, the temperature at which conjugate fibers begin to fuse together is less than Tll1° C.). Preferably, (T −15) to (
TIll-3)'C is better.

If this temperature is too low, the decrease in water solubility caused by crystal orientation cannot be sufficiently recovered. On the other hand, if it is too high, fusion will occur between single yarns or yarns of the composite 11t, which will worsen the unwinding of the yarn from the wound package and reduce workability and productivity in higher processing steps. , even 1
of textile products.

This results in quality deterioration. In addition, when a textile product is heat-treated after being made into a textile product, the fusion of the fibers inhibits the elution of water-soluble components and deteriorates the quality of the product, such as the feel of the product.

Moreover, the time for this heat treatment should be such that the temperature of the fiber itself to be treated reaches the above-mentioned temperature range. for example,
In the case of a contact type hot plate, the contact time may be about 0.005 to 0.5 seconds. Additionally, when high-level processed textile products such as fabrics and knitted fabrics are placed in or passed through an oven or the like and are heat-treated with warm air, it takes some time for the fibers themselves to reach the above temperature range, so generally , a few seconds to 10
It only takes about a minute.

[Function] The conjugate fiber to which the method of the present invention is applied has, as at least one component thereof, a copolymerized polyester that is insoluble in cold water and soluble in hot water and the like. This property of being insoluble in cold water and soluble in hot water is very important in producing composite fibers by melt spinning. In other words, if it is soluble in cold water, the generally used method of cooling the molten polymer into a water bath after the completion of the polycondensation reaction cannot be used, and chips and fibers cannot be exposed to air. It is difficult to industrially produce stable composite fibers because they are deformed by moisture.

Copolymerization of a specific amount of 5-sulfoisophthalic acid is essential for making polyester water-soluble, but in order to make it easily soluble in hot water and insoluble in cold water, a specific amount of isophthalic acid and/or C3-20 aliphatic acid is required to make polyester water-soluble. It is necessary to also copolymerize dicarboxylic acids.

In the method of the present invention, the molecular chains of the water-insoluble component are crystallized by stretching to improve the strength characteristics of the fiber. This crystal orientation by stretching improves the handling properties of composite LLI fibers during high-order processing, and is necessary for the water-insoluble component fibers that remain after dissolving and removing the water-soluble copolyester component with hot water, etc. This is necessary to impart strong strength characteristics.

However, with this stretching alone, the water-soluble copolyester component becomes poorly soluble in hot water, so in order for this copolyester component to fully exhibit its original solubility in hot water,
It is necessary to perform heat treatment at the specific temperature mentioned above. This heat treatment can sufficiently restore the solubility of water-insoluble components in hot water, etc., and can increase the solubility to the level at the chip or undrawn yarn stage. However, even by this heat treatment, the crystallization and orientation of the molecular chains on the water-insoluble component side are hardly disturbed, and the strength characteristics are not substantially deteriorated.

The copolymerized polyester component in the 1q composite fiber can be dissolved and removed by treatment with hot water or the like by immersing it in hot water or the like. For example, when this copolymerized polyester is used as the sea component of a sea-island type composite fiber, it is possible to extremely easily reduce the ultrafine fiber to 1q by treatment with hot water, etc. In the case of arranged conjugate fibers, it is possible to obtain irregular cross-section yarns with special shapes. Furthermore, it may be used to produce special mixed yarns as splittable conjugate fibers. In this way, hot water treatment etc. can be carried out at the yarn stage. Alternatively, it may be made into a knitted fabric or the like to produce a product with unique bulkiness, elasticity, texture, etc.

The water-insoluble fiber obtained by this hot water treatment has excellent physical properties because the molecular chains are in a crystal oriented state.

[Example] Hereinafter, the present invention will be explained in more detail with reference to Examples.

Note that parts in the examples mean parts by weight.

- Examples 1 to 3 and Comparative Examples 1 to 4 Dimethyl terephthalate, which is a methyl ester of terephthalic acid (TPA), 87.6? iIP, isophthal fly (
37.1 parts of dimethyl isophthalate, which is a methyl ester of IPA), 93.3 parts of ethylene glycol, and 0.135 parts of calcium acetate were charged into a reaction vessel and the mixture was heated to 130-2.
The transesterification reaction was carried out at 30° C. while distilling off the by-product methanol. Then, 5-sodium sulfoisophthal M
(27.2 parts of dimethyl 5-sodium sulfoisophthalate, the methyl ester of 31>, 0 antimony trioxide)
．． 0.03 parts, phosphoric acid 0.0075 parts and lithium acetate 0
．． After collecting 3 parts and reacting for 1 hour at 230-250°C, condensation polymerization was carried out for 3 hours under reduced pressure at 250-275°C. After polymerization, in a water bath at room temperature. The polymer was discharged, cooled, made into guts, and cut into chips.The jqed polymer (polymer No. 1) was
It has the composition shown in Table 1, and its IV (intrinsic viscosity in orthochlorophenol solution) is 0.68 and softening point is 129.
It was ℃.

In addition, the copolymerization components and their proportions in the above copolymerized polyester were changed as shown in Table 1, and the above polymer No.
Copolymerized polyesters of Polymer No. 26 and Polymer No. 3 were polymerized in the same manner as in the case of Polymer No. 26 and Polymer No. 3. Its characteristics were as shown in Table 1.

On the other hand, 1q of the dried chips were vacuum-dried at the temperature and time shown in Table 1 to obtain dry copolymerized polyesters, and each of these dried copolyesters and homopolyethylene terephthalate (PET) chips with an IV of 0.70 were mixed into 150%
℃, dried PET for 6 hours under vacuum was melted separately using a screw extruder (285℃), and using a gear pump,
A split-type composite spinneret with a composite form in which T is divided into 8 parts (24
Hall) for composite spinning. At this time, the copolyester has a cross-sectional shape that extends in eight radial directions from the fiber center, and its discharge m is 6. ．． It was 75g/min. On the other hand, PET occupies 8 ffl (island component) divided by copolymerized polyester, and its discharge amount is 20.750
It was a part. The composite yarn spun from the spindle hole is air-cooled,
After oiling with modified olefins, it was wound at 900 m/min. The obtained undrawn yarn was passed through a hot pin and a hot plate at the temperatures shown in Table 2 and drawn 3.98 times to obtain a drawn yarn of 70 denier and 24 filaments. Note that the heat treatment time on the hot plate was about 0.06 seconds.

The water properties of the obtained undrawn yarns and drawn yarns, as well as the strength and elongation of the drawn yarns, fusion initiation temperature (TIII), and winding condition were evaluated using the following methods, and the results are shown in Table 2. .

Change in cold water: Approximately 10 total composite yarns in water at 30℃
After immersing the composite yarn for 20 hours, changes in the surface and cross section of the copolymerized polyester layer in the composite yarn were examined by observation and cross-sectional micrographs. In addition, the change in fiber weight was examined, and the reduction rate was expressed as a percentage of the weight of the copolyester component.

Changes in hot water 2 After immersing approximately 19 total composite yarns in 100CI of 95°C hot water for 20 minutes, changes in the surface and cross section of the copolyester layer in the composite yarns were examined by observation and cross-sectional micrographs. Ta. In addition, the change in fiber weight was investigated, and the reduction rate was expressed as a percentage of the weight of the copolyester component.

Melting start temperature of drawn yarn (T, ): sample composite yarn at 20
The temperature at which fusion begins to occur (TIIl ) was measured.

Winding condition of the drawn yarn: The surface fuzz of the obtained package and the unwinding property of the yarn from the package were examined by observation.

From the results in Table 2, when heat treated under the temperature conditions specified in the method of the present invention, the copolymerized polyester component of the drawn yarn had high hot water solubility and could be completely dissolved in hot water.

On the other hand, when the heat treatment temperature is too low (Comparative Example 1.2
．． In case 4), the decrease in hot water solubility of the copolyester component due to stretching could not be recovered, and when the gross sample used for the solubility test in hot water was examined, it was found that the elution of the copolyester was incomplete. Some of the PET monofilaments were glue-like and others were swollen and only partially eluted, and both were unsuitable for the intended ultra-fine multi-single threads.

In addition, when the heat treatment temperature was too high (Comparative Example 3), the hot water solubility of the copolymerized polyester component was good, but the heat treatment caused the fibers to fuse together, making it difficult to unwrap them from the wound package. It was bad sex.

Next, using the drawn yarn of Example 1, a @knitted fabric was knitted,
It was immersed in clear water for 20 minutes and then dried.

The knitted fabric weighs 6.90g (about 1m long) before dipping.
By dipping, the weight is reduced to 5.180, making it extremely soft and supple to the touch, and at the same time, the 24-filament drawn yarn has an ultra-fine 192-filament yarn.
! It was roughly divided.

- Example 4 and Comparative Example 5 Using the vacuum-dried copolyester of polymer No. 2 used in Example 2 and dry PET, the copolymer polyester discharge amount was 7.94Q1 minute, and the PET discharge amount was 31 minutes. ．．
Composite spinning was carried out in the same manner as in Example 2 except that the spinning speed was 760/min. The composite yarn spun from the spinneret hole was air-cooled and oiled, then taken up at high speed and wound at 3500 m/min without being stretched.

The obtained intermediately oriented yarn was heated with a heat pin at 60°C and
The yarn was drawn by -1.48 times by passing through a hot plate at 60°C or 60°C to obtain a drawn yarn of 71 denier and 24 filaments.

The properties of the obtained intermediately oriented yarns and drawn yarns are as shown in Table 3. Even when intermediately oriented yarns are drawn by high-speed spinning, heat treatment under the temperature conditions specified by the method of the present invention does not affect the quality of the drawn yarns. This was effective for increasing the hot water solubility of copolymerized polyester.

- Example 5 Using the drawn yarn prepared in Comparative Example 1, a tubular knitted fabric was knitted. This cylindrical knitted fabric was heat-treated in an oven at 170° C. for 5 minutes, immersed in clear water for 20 minutes, and then dried.

When we measured the weight of the cylindrical knitted fabric obtained by dipping it in this clean water, we found that the weight and amount of the fabric had decreased by an amount corresponding to the copolyester component (approximately 25%) compared to before the dipping treatment. Moreover, the touch became very soft and supple, and at the same time, the drawn yarn of 24 filaments was divided into ultra-fine 111M of 192 filaments.

As described above, the heat treatment specified by the method of the present invention is effective even when performed at the stage of producing textile products.

[Effects of the Invention] The composite fiber produced by the method of the present invention (9) has its water-insoluble components sufficiently crystal-oriented by stretching and exhibits good physical properties, and the water-soluble components are Since it is soluble in water, etc., the above-mentioned water-soluble components can be sufficiently and easily removed by treatment with hot water, etc., and as a result, ultrafine fibers and irregular cross-section fibers with favorable physical properties can be produced. can be easily obtained.

Moreover, since the water-soluble component of this composite 1IitIL is insoluble in cold water, it is not deformed in steps such as high-order processing, is easy to handle, and is suitable for industrial production.

In addition, water-soluble components can be easily removed from this composite fiber by treatment with hot water, warm water, or even dilute alkaline water, so it is advantageous in terms of safety in this treatment and wastewater treatment.

Claims (1)

[Claims] As a copolymerization component, 5 to 15 mol% of 5 to the total acid component.
- Sodium sulfoisophthalic acid, 5 to 5 to total acid components
50 mol% isophthalic acid and/or 3-2 carbon atoms
0 aliphatic dicarboxylic acid and 0 to 0 for all polymers.
20 wt% of polyanhydrides from aliphatic dicarboxylic acids having 3 to 20 carbon atoms and/or an average molecular weight of 400 to
6,000 polyalkylene glycol or its derivative, and whose main acid component is terephthalic acid, is melt-spun as at least one component of a composite fiber, and then stretched to have a water-soluble component. In the method for producing composite fibers, after the stretching, the softening temperature (T_
at a temperature not less than [(T_S-20) °C] that is 20 degrees lower than S °C) and at a temperature that does not cause fusion of the composite fibers,
A method for producing a composite fiber having a water-soluble component, the method comprising heat-treating the fiber.