JPH09278281A - Polyurethane elastic fiber wind and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the occurrence of density groups or stripes when cross weaving with nylon or polyester fibers is performed and high-temperature or high-temperature and high-pressure dyeing is performed by setting a relative viscosity difference between the innermost layer and the outermost layer of a wind after heating and aging to a specified value and storage elasticity in the specified temperatures of the innermost and outermost layers to a specified value or over. SOLUTION: When a melted and spun polyurethane fiber is subjected to heat treatment and solid polymerization is performed, by considering not only a moisture content but also a temperature/atmosphere heat treatment condition or the like, a polyurethane elastic fiber more uniform in material quality is obtained. Even for high-temperature and high-pressure dyeing when cross weaving is performed with other fibers such as nylon or polyester fibers, the occurrence of density groups or stripes is prevented. In other words, when a fabric obtained by cross weaving with a fiber such as nylon having a high melting point is dyed in a high temperature or in a high temperature and by a high pressure, a relative viscosity difference between the innermost layer and the outermost layer of the wind is set to 0.10 to -0.10, or preferably 0.05 to -0.10, and a storage elasticity in a temperature of 130 deg.C is set to 4.5×10<7> dyn/cm<2> or over, preferably 6.0×10<7> dyn/cm<2> or over.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a polyurethane elastic fiber wound body obtained by melt spinning of polyurethane. More specifically, it relates to a polyurethane elastic fiber wound body having excellent homogeneity of various physical properties such as heat resistance and elastic recovery.

[0002]

2. Description of the Related Art As a method for producing a polyurethane elastic fiber, methods such as a dry spinning method, a wet spinning method and a melt spinning method are known. Among them, the polyurethane elastic fiber obtained by the melt spinning method has a heat setting property. In addition, because of its excellent wear resistance and transparency, and its low manufacturing cost, its production amount has been increasing in recent years. However, the polyurethane elastic fiber obtained by the melt spinning method is stronger than the polyurethane elastic fiber obtained by the dry spinning method.
It is difficult to form de-segments, so that it tends to be inferior in hot water resistance and heat resistance.

Various proposals have been made to solve such problems. For example, after melt-spinning polyurethane and winding it on a yarn tube or the like, heat treatment is performed at a temperature of 60 to 150 ° C. for 1 to 48 hours. Solid phase polymerization to accelerate the formation of hard segments. However,
Polyurethane elastic fiber obtained by using the solid phase polymerization method has a problem of homogeneity in the same cheese.
When high-temperature dyeing or high-temperature high-pressure dyeing is performed by knitting with a fiber having a high melting point such as polyester fiber, density spots and meridian lines are generated.

In order to solve such a problem, the present inventors have adopted a method of performing heat aging under the condition that the amount of water in the polyurethane elastic fiber is suppressed to a certain amount or less, whereby the same cheese can be used. The homogeneity of the fibers in the fiber is improved, and when the fibers are knitted with other fibers such as nylon fiber and polyester fiber and dyed at high temperature and at high temperature and high pressure, the warp caused by the heterogeneity of various physical properties of polyurethane elastic fiber We found that it could be improved, and filed a prior application (Japanese Patent Application No. 5-315109).
issue). However, the polyurethane elastic fiber obtained by this method has a large physical property of polyurethane elastic fiber such as warp generated when it is knitted with other fibers such as nylon fiber and polyester fiber and dyed at high temperature and at high temperature and high pressure. Although the inhomogeneity is eliminated, it was found that there is still room for improvement because it is not sufficient to eliminate density unevenness that requires strict homogeneity.

[0005]

In order to solve the above-mentioned problems, the present inventors have further studied the solid-state polymerization method of polyurethane elastic fibers obtained by the melt spinning method, and as a result, found that a conventionally known thermoplastic polyurethane was obtained. By controlling the amount of water contained in the yarn during solid state polymerization and specifying the conditions during heat aging, the homogeneity of various physical properties such as hot water resistance and elastic recovery within the same cheese can be achieved. It was found to be excellent, and it is possible to suppress the occurrence of density spots and meridians when high-temperature dyeing or high-temperature high-pressure dyeing is performed by interwoven with nylon or polyester fibers,
The present invention has been reached.

[0006]

[Means for Solving the Problems] That is, the present invention relates to a polyurethane elastic fiber that is melt-spun and wound, and has a relative viscosity difference between the innermost layer portion and the outermost layer portion of the wound body after heat aging. 0.10 to -0.10, and the storage elastic modulus at 130 ° C. of the innermost layer portion and the outermost layer portion of the wound body is 4.5 × 10 ⁷ dyn / cm ² or more. It is a polyurethane elastic fiber wound body and is a manufacturing method thereof.

Hereinafter, the present invention will be described in detail. In the present invention, the polyurethane elastic fiber is a polyurethane elastic fiber obtained by melt spinning a thermoplastic polyurethane obtained by reacting a polymer polyol, an organic diisocyanate and a chain extender. When melt-spinning polyurethane, a part of the polyurethane is NCO group and O in the molten state.
It is dissociated into H groups, and the recombination reaction in the dissociated state progresses after spinning, and the thread quality and thermal properties change over time.
This is because the dissociated NCO group reacts with alcohol, water, etc. to form a urethane bond and a urea bond, and further dissociated NCO
The CO group reacts with a urethane bond and a urea bond to form a primary structure such as an alohanate bond and a buret bond, and at the same time forms a higher-order structure such as microphase separation property and hard segment cohesive property of polyurethane. For this reason, after spinning, it is necessary to carry out a heat treatment under certain conditions to complete the reaction, and the progress of this reaction improves improvements in elastic recovery and hot water resistance.

Polyurethane elastic fiber is generally 200
It has a water content of 0 to 5000 ppm,
When the amount of water contained in polyurethane elastic fiber increases,
In each layer in the same wound body, the moisture content of the fibers is different, and the moisture content varies, and the NCO group and water react with each other in the portion having a large moisture content to cause chain extension, resulting in microseparability of polyurethane, hard The progress of the cohesiveness of the segment is hindered, the heat resistance and the hot water resistance become poor, and the homogeneity of the physical properties of the wound body is lacking. Therefore, physical properties such as hot water resistance vary in each layer in the same wound body, and density unevenness and warp are generated when high temperature dyeing is performed by interwoven with nylon or polyester fibers.
Even if the moisture content of the polyurethane elastic fiber immediately after melt spinning is lowered, if the relative humidity of the atmosphere during temporary storage until heat treatment or transfer to the heat treatment chamber is high, the polyurethane elastic fiber easily absorbs moisture and the interlayer The water content in the
The above problems occur.

However, when the melt-spun polyurethane fiber is heat-treated for solid phase polymerization, attention is paid not only to the moisture content in the polyurethane elastic fiber, but also to the temperature,
By paying attention to heat treatment conditions such as atmosphere, polyurethane elastic fibers having even more uniform physical properties can be obtained, and density unevenness can be obtained even at high temperature and high pressure dyeing of a knitted fabric with other fibers such as nylon and polyester. The present inventors have found that the generation of the meridian muscles does not occur.

As described above, as an index for evaluating the nonuniformity of the reaction and the nonuniformity of the agglomeration state of the hard segments, the innermost layer and outermost layer of the polyurethane elastic fiber wound body after heat treatment are used. Relative viscosity difference (Δη: relative viscosity of fibers in innermost layer-relative viscosity of fibers in outermost layer) and 1
The storage elastic modulus at 30 ° C. (dynamic elastic modulus) is used.
That is, when dyeing a knitted fabric with a fiber having a high melting point such as nylon or polyester at a high temperature and at a high temperature and a high pressure,
The relative viscosity difference between the fibers of the innermost layer and the outermost layer of the wound body is 0.10 to -0.10, preferably 0.05 to -0.0.
5, and the storage elastic modulus at 130 ° C. is 4.5 × 10 ⁷
dyne / cm ² or more, preferably 6.0 × 10 ⁷ dyne / cm ²
It is important that this is the case.

The above relative viscosity difference is 0.10 to -0.10.
If the range is not satisfied, the physical properties of the fibers of the same wound body will be lacking in homogeneity.When dyed by knitting or weaving with fibers such as nylon and polyester, the physical properties of polyurethane elastic fibers will be inhomogeneous. Density spots and meridians are generated due to the sex, and the quality deteriorates, resulting in poor practicability.

Even if the above relative viscosity difference is satisfied, the storage elastic modulus at 130 ° C. is 4.5 × 10 ⁷ dyne.
If it is less than / cm ^2, the homogeneity of various physical properties of the fiber of the wound body is improved, but when it is subjected to high temperature and high pressure dyeing by interwoven with fibers such as nylon and polyester, the heat resistance and hot water resistance are Insufficient to withstand mixing with such fibers.

The polyurethane elastic fiber having the above-mentioned properties can be obtained by heat-treating a wound body wound after melt spinning under specific conditions. The conditions will be described in detail. First, the water content of the wound fiber is 1000 ppm or less, preferably 500 ppm or less, and particularly 300 ppm.
It is to do the following. There are several methods for reducing the moisture content of the fiber, for example, a method of performing low temperature from spinning to a heat treatment step, a method of dehydrating before the heat treatment step,
Examples include a method of performing heat treatment under reduced pressure at a low temperature of 50 to 70 ° C. As described above, since the polyurethane elastic fiber easily absorbs moisture, even if the moisture content of the fiber immediately after melt spinning is lowered, when the relative humidity of the atmosphere is high during temporary storage until the heat treatment or transfer to the heat treatment chamber, Care must be taken because the moisture content between the layers of the thread becomes non-uniform and the moisture content of the fiber increases. When the heat treatment is performed while the water content in the polyurethane elastic fiber exceeds 1000 ppm, the progress of phase microseparability of polyurethane and the hard segment cohesiveness of polyurethane is hindered, and heat resistance,
The fiber has poor hot water resistance.

The heat treatment temperature and heat treatment atmosphere are also important factors. Conventionally, in the heat treatment step, for the purpose of improving heat resistance and hot water resistance, for example, a heat treatment condition of 50 to 120 ° C. in a low dew point atmosphere of −30 ° C. or lower is generally used, but in a heat treatment simply at low humidity, The heterogeneity of physical properties of polyurethane elastic fiber was not improved. After reducing the water content in the polyurethane elastic fiber to 1000 ppm or less, the gas dew point is −20 to 25 ° C. and the temperature is 50 to 10
Strictly speaking, it is necessary to select the gas dew point of the heat aging step within the above range in accordance with the moisture content of the elastic fiber immediately before heat aging by heating and aging it in an atmosphere of 0 ° C. is there. For example, under heat aging conditions of 90 ° C. and 20 hours, when the moisture content of the fiber is 500 ppm, the gas dew point is −10 to 10 ° C., and the moisture content of the fiber is 200 pp.
When m, the gas dew point is -20 to 0 ° C. When the gas dew point does not satisfy the above range, the physical properties such as heat resistance and hot water resistance in each layer of the same wound body become non-uniform. In the heat aging step, the moisture content of the polyurethane elastic fiber and the gas dew point of the atmosphere are not necessarily low, and if the value is low, the physical properties such as heat resistance and hot water resistance in each layer of the same wound body are improved. If the gas dew point during the heating and aging process is not appropriate, the physical properties of the fiber will be inhomogeneous.

The temperature of the heat aging step is in the range of 50 to 100 ° C. When the heating temperature is less than 50 ° C., it is preferable in terms of homogeneity of various physical properties between layers of the same wound body, but heat resistance,
It is very inferior in hot water resistance. On the other hand, if the heating temperature exceeds 100 ° C., it is preferable in terms of heat resistance and hot water resistance, but coloring and sticking of the elastic fiber, and further, homogeneity of various physical properties between layers of the same wound body are deteriorated. The heat aging time is preferably 1 to 48 hours from the viewpoint of heat resistance, hot water resistance, and homogeneity of various physical properties between layers of the same wound body. Especially 3
~ 36 hours is preferred. Further, when the elastic fiber is wound up using a hygroscopic thread tube, the inner layer portion of the wound thread is affected by the water content in the thread tube. Therefore, it is preferable to use a thread tube that has been dehydrated in advance. It is more desirable to use a thread tube that does not easily absorb moisture. In this way, the moisture content of the elastic fiber before heat aging is reduced, and the adjustment of the gas atmosphere dew point and the heating temperature during heat aging improves the physical properties of the polyurethane elastic fiber and also improves the homogeneity of the physical properties. It is important above.

In the present invention, known thermoplastic polyurethane can be used. The high molecular diol constituting the polyurethane has an average molecular weight of 1,000 to 600.
It is possible to use at least one of 0, preferably 1000 to 5000 polyester polyols, polycarbonate polyols, polyester polycarbonate polyols, polyether polyols and polyether ester polyols. The polyester polyol will be described. As the diol component, 1,4-butane diol, 1,5-pentane diol, 1,6-hexane diol, 1,8-octane diol, 1,9-nonane diol, etc. Diol; Branched diol such as 2-methyl-1,3-propanediol, neopentyl glycol, 3-methyl-1,5-pentanediol, 2-methyl-1,8-octanediol, etc. Alicyclic diols such as cyclohexane dimethanol and the like. Further, polyfunctional polyols such as glycerin, trimethylolpropane, butanthol, hexanetriol, trimethylolbutane and pentaerythritol may be used in combination.

As the dicarboxylic acid constituting the polyester polyol, linear dicarboxylic acids such as glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid and decanedicarboxylic acid, or esters thereof. Aromatic dicarboxylic acids such as terephthalic acid, phthalic acid, isophthalic acid, and naphthalenedicarboxylic acid or ester-forming derivatives thereof; alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid or ester-forming derivatives thereof; branching Examples thereof include dicarboxylic acids or ester-forming derivatives thereof. Furthermore, polycarboxylic acids such as trimellitic acid may be used in combination.

Heat resistance of the resulting polyurethane elastic fiber,
From the viewpoint of hot water resistance, 3-methyl-
C6-10 having one methyl branch such as 1,5-pentanediol and 2-methyl-1,8-octanediol
A diol; a mixture of the diol and a linear diol having 6 to 10 carbon atoms is used, and a dicarboxylic acid having 4 to 10 carbon atoms such as azelaic acid, sebacic acid and adipic acid is used as the dicarboxylic acid component. It is preferable. The polyester polyol used for producing the polyurethane may be a single polyester polyol or a mixture of two or more kinds of polyester polyols, which are separately polymerized using two or more kinds of polyester polyols. You may mix and use polyurethane.

The organic diisocyanate used in the synthesis of polyurethane in the present invention includes 4,4'-diphenylmethane diisocyanate, p-phenylene diisocyanate, toluylene diisocyanate and 1,5-naphthylene diisocyanate. There are diisocyanates having a molecular weight of 500 or less, such as nato, xylylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, and 4,4'-dicyclohexylmethane diisocyanate, but the molecular weight is preferably. It is an organic diisocyanate of 200 to 500, and 4,4'-diphenylmethane diisocyanate is particularly preferable. As the organic diisocyanate, a compound having a blocked isocyanate group that is converted into a free isocyanate may be used.

As the chain extender, a low molecular weight compound having at least two hydrogen atoms capable of reacting with an isocyanate, for example, ethylene glycol having a molecular weight of 400 or less is used.
, Propylene glycol, 1,4-butanediol,
1,4-bis (2-hydroxyethoxy) benzene,
Examples include diol such as 1,6-hexanediol and 3-methyl-1,5-pentanediol; diamines such as hydrazine and propylenediamine. These chain extenders may be used alone or in combination of two or more kinds. In particular, the heat resistance of the resulting polyurethane,
1,4-butanediol, 1,4 in terms of hot water resistance
It is preferred to use -bis (2-hydroxyethoxy) benzene.

Each component of the polyurethane used to obtain the polyurethane elastic fiber of the present invention, such as polymer diol (A), organic isocyanate (B), chain extender (
The composition ratio of (C) is such that the molar ratio of (B) / [(A) + (C)] is 0.99 or more in terms of heat resistance and hot water resistance of the fiber.
It is preferably 1.20, more preferably 1.00 to 1.15. The polyurethane elastic fiber in the present invention can be obtained by thermoplastically polymerizing at the above composition ratio, or by adding and mixing a polyisocyanate compound at the time of spinning, and melt-spinning polyurethane at the above composition ratio. Further, from the viewpoint of improving the polymerization or spinning speed, a small amount of a tin-based catalyst having urethanization reaction activity may be contained for polymerization and spinning.

[0022]

EXAMPLES The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples. Each measured value in the examples was measured and evaluated by the following method. (1) Moisture Content of Fiber (ppm) The moisture content of the fiber immediately after spinning was measured by the Cal-Fisher method. Then put the wound body of the fiber in a closed container,
It was dried under reduced pressure with a vacuum pump. Two traps (refrigerant: acetone and dry ice) were installed between the vacuum pump and the container to collect evaporated water and oil. After that, take out the water and the oil from the trap and separate only the water,
The weight was measured, and the amount of water remaining in the bobbin was calculated from the water content immediately after spinning. It should be noted that a paper thread tube (bobbin)
Contains a considerable amount of water, so a bobbin made of Beclat, which contained almost no water, was used for the measurement wound body. Similarly, a closed container made of polycarbonate containing almost no water was used. Furthermore, it was confirmed that the water content of all the devices was low, and that it did not affect the water content of the wound body. (2) Relative viscosity of fiber 0.5 g / d of polyurethane elastic fiber of each layer of the wound body
N, N containing 1% by weight of n-butylamine such that
-Dissolved in dimethylformamide, stirred at 20 ° C for 24 hours, then measured with an Ubbelohde viscometer in a constant temperature bath at 30 ° C, and calculated from the following formula to obtain the difference. ηr = t / t ₀ Here, t is the number of fall seconds measured for the sample solution, and t ₀ is the drop measured for N, N-dimethylformamide containing 1% by weight of the solvent n-butylamine as a solvent with the same Ubbelohde viscometer. Is the number of seconds.

(3) Elastic recovery rate The sample was stretched by 300% and held at room temperature for 2 minutes, the tension was removed, and the elastic recovery rate was measured after standing for 2 minutes. Elastic recovery rate = {1- (L−L ₀ / L ₀ )} × 100
(%) However, L: Length of sample after leaving for 2 minutes after tension removal L ₀ : Length of sample before elongation (4) Storage elastic modulus (evaluated by dynamic viscoelasticity) 40 denier 100 samples are evenly arranged, both ends are adhered with an adhesive, and using a dynamic viscoelasticity measuring device (DVE Rheospectler manufactured by Rheology Co., Ltd.), automatic static load, displacement amplitude 10 micro, frequency 11 Hz, rising Temperature rate 3 ℃
The temperature dispersion of the storage elastic modulus E ′ was measured in 1 / min. (5) Evaluation of density unevenness and warp after dyeing As the yarn for a 40-denier nylon fiber or polyester fiber two-weight ricott, the outermost layer and the innermost layer of the polyurethane elastic fiber of the same wound body were inserted in order. The knitted fabric was knitted. The degree of density spots and warps after high-temperature dyeing or high-temperature high-pressure dyeing of these knitted fabrics was evaluated under the following conditions. High temperature dyeing conditions (nylon fiber): Dyeing temperature 95 ° C Dyeing time 30 minutes Bath ratio 1/20 Dye Suminol Milling Brilliant Red BS

High-temperature and high-pressure dyeing conditions (polyester fiber): Dyeing temperature 125 ° C. Dyeing time 60 minutes Bath ratio 1/30 Dye Sumikaron Navy Blue
SE-RPD

Evaluation Criteria for Density Spots ⊚: There is no density spots and there is a feeling of power. ◯: Almost no density unevenness is seen and there is a power feeling. Δ: Density unevenness is slightly observed. X: Many density spots are seen. *: The density is remarkably decreased as a whole and the power feeling is insufficient. Evaluation criteria for meridians ◎: No occurrence of meridians. ○: Almost no occurrence of meridian muscles. Δ: Generation of meridian muscles is slightly observed. X: Many meridian muscles are observed.

For each measurement, two layers, that is, the outermost layer and the innermost layer of the same wound body of the sample were measured. The sampling points of each layer of the same wound body of the measured sample will be described. 2m from the outermost part of the cheese outer periphery when the fiber is wrapped with full cheese
The outermost layer was within m, and the innermost layer was within 2 mm from the yarn tube inside the cheese closest to the yarn tube. However, within 5 mm from the end face of the cheese end face portion was excluded from the measurement. The size of the full cheese is such that the cheese diameter from the thread tube to the outermost layer is 30 mm and the cheese width is 40 mm.

The compounds used are indicated by abbreviations, and the relationships of the abbreviation compounds are as follows. MPD: 3-methyl-1,5-pentanediol AD: adipic acid AZ: azelaic acid BD: 1,4-butanediol PMPA: number average molecular weight 2000 composed of MPD and AD
Polyester Polyol PMAZ: Number average molecular weight 2000 composed of MPD and AZ
Polyester polyol PBMA: Polyester polyol having a number average molecular weight of 2000 consisting of a mixture of MPD / BD (3/1) and AD MDI: 4,4′-diphenylmethane diisocyanate

Example 1 A mixture of PMAZ and BD heated to 80 ° C. and MDI heated to 50 ° C. were melted into PMAZ / MD.
I / BD was continuously fed to a twin-screw extruder with 30φ and L / D = 36 by a metering pump so that the used composition molar ratio was as shown in Table 1, and continuous melt polymerization was performed at 240 to 260 ° C. This is supplied as it is to a spinning machine with a single-screw extruder,
Spinning was carried out at a spinning temperature of 215 to 235 ° C., a cooling air dew point of 10 ° C. and a spinning speed of 500 m / min to obtain a polyurethane elastic fiber wound body having a moisture content of 4000 ppm of 40 denier / filament. This fiber (rolled body) was dehydrated at 40 ° C. for 5 hours with a vacuum dryer at a pressure of 1 Torr to obtain a fiber-containing water content of 50.
After adjusting to 0ppm, the dew point is 0 ℃ under the humidity of 90 ℃ × 24
It was heat-treated for an hour and then left to stand at 25 ° C. and 50% relative humidity for 7 days. The physical properties of the fiber and the fabric knitted with the polyester fiber were evaluated. Table 2 shows the results.

Example 2 In Example 1, the wound body was wound at 40 ° C. for 1 hour at a pressure of 1T.
Dewatered with a vacuum dryer at orr and the water content in the fiber is 900p
After setting to pm, it was heat-treated at a dew point of 10 ° C. for 90 hours at 90 ° C. for 24 hours, and further left at a temperature of 25 ° C. and 50% relative humidity for 7 days. The physical properties of the fiber and the fabric knitted with the polyester fiber were evaluated. Table 2 shows the results.

Example 3 In Example 1, the wound body was wound at 40 ° C. for 5 hours at a pressure of 0.
Dehydrated with a 5 Torr vacuum dryer to reduce the fiber water content to 25
After setting to 0ppm, dew point is 90 ℃ under humidity of 10 ℃ × 2
Heat-treat for 4 hours, then 7 hours at 25 ° C and 50% relative humidity.
Left for days. The physical properties of the fiber and the fabric knitted with the polyester fiber were evaluated. Table 2 shows the results.

Examples 4 to 6 Polyurethane elastic fiber wound bodies were obtained in the same manner as in Example 1 except that the composition ratios of polyester polyol, diisocyanate and chain extender were as shown in Table 1. . This wound body is heated at 40 ° C. for 5 hours at a pressure of 1.0 Torr.
After dehydration with a vacuum dryer of No. 1 to make the fiber-containing water content 500 ppm, heat treatment was performed at 90 ° C. for 24 hours at a dew point of 10 ° C., and further left at 25 ° C. and 50% relative humidity for 7 days. The physical properties of the fiber and the fabric that was interwoven with polyester fiber or nylon fiber were evaluated. Table 2 shows the results.

Comparative Example 1 A polyurethane elastic fiber wound body having a moisture content of 4000 ppm in Example 1 was directly subjected to a dew point of −30 ° C. under a humidity of 9
It was heat-treated at 0 ° C. for 24 hours and then left to stand at 25 ° C. and 50% relative humidity for 7 days. The physical properties of the fiber and the fabric knitted with the polyester fiber were evaluated. Table 2 shows the results. The outermost layer and the innermost layer of the wound yarn had irregularities in the physical properties, the knitted fabric had irregularities in density, and many occurrences of warp lines were observed.

Comparative Example 2 In Example 1, the wound body was heated at 40 ° C. for 5 hours at a pressure of 1.
Dehydrated with a vacuum dryer at 0 Torr to reduce the water content in the fiber to 50
After adjusting to 0 ppm, the dew point is −30 ° C. and the humidity is 90 ° C. ×
It was heat-treated for 24 hours and then left standing at 25 ° C. and 50% relative humidity for 7 days. The physical properties of the fiber and the fabric knitted with the polyester fiber were evaluated. Table 2 shows the results. Since the dew point was low, the density of the knitted fabric was severe and it was not suitable as a product.

Comparative Example 3 In Example 1, the wound body was heated at 40 ° C. for 5 hours at a pressure of 1.
Dehydrated with a vacuum dryer at 0 Torr to reduce the water content in the fiber to 50
After adjusting to 0ppm, 90 ℃ × 2 under the humidity of 30 ℃
Heat-treat for 4 hours, then 7 hours at 25 ° C and 50% relative humidity.
Left for days. The physical properties of the fiber and the fabric knitted with the polyester fiber were evaluated. Table 2 shows the results. The uneven density of the knitted fabric was severe and the power feeling of the fabric was slightly insufficient.

Comparative Example 4 In Example 1, the wound body was wound at 40 ° C. for 1 hour at a pressure of 5.
Dehydrated with a vacuum dryer at 0 Torr to reduce the water content in the fiber to 20
After making it to 00ppm, under dew point of humidity of 20 ℃, 90 ℃ ×
It was heat-treated for 24 hours and then left standing at 25 ° C. and 50% relative humidity for 7 days. The physical properties of the fiber and the fabric knitted with the nylon fiber were evaluated. Table 2 shows the results. The density of the knitted fabric was severe and many warp lines were observed. Furthermore, the power feeling of the fabric was inferior.

Comparative Example 5 In Example 1, the wound body was heated at 40 ° C. for 5 hours at a pressure of 1.
Dehydrated with a vacuum dryer at 0 Torr to reduce the water content in the fiber to 50
After setting to 0ppm, dew point is 20 ℃ under humidity, 40 ℃ × 3
Heat-treat for 6 hours, then heat at 25 ° C and 50% relative humidity for 7 hours.
Left for days. The physical properties of the fiber and the fabric knitted with the polyester fiber were evaluated. Table 2 shows the results. Since the heat treatment temperature was low, the texture of the fabric was inferior.

Comparative Example 6 In Example 1, the wound body was heated at 40 ° C. for 5 hours under a pressure of 1.
Dehydrated with a vacuum dryer at 0 Torr to reduce the water content in the fiber to 50
After adjusting to 0ppm, 120 ℃ x under dew point humidity of 20 ℃
Heat-treat for 3 hours, then 7 hours at 25 ° C and 50% relative humidity.
Left for days. The physical properties of the fiber and the fabric knitted with the polyester fiber were evaluated. Table 2 shows the results. Since the heat treatment temperature was too high, there were many density spots on the fabric.

Comparative Examples 7 to 8 Polyurethane elastic fiber wound bodies were obtained in the same manner as in Example 1 except that the composition ratios of polyester polyol, diisocyanate and chain extender were as shown in Table 1. . This wound body is heated at 40 ° C. for 5 hours at a pressure of 1.0 Torr.
After dehydration with a vacuum dryer of No. 1 to make the water content in the fiber 500 ppm, heat treatment was performed at 90 ° C. for 24 hours under a humidity with a dew point of 0 ° C., and then the mixture was allowed to stand at 50% relative humidity of 25 ° C. for 7 days. The physical properties of the fiber and the fabric knitted with the nylon fiber were evaluated. Table 2 shows the results.

[0039]

[Table 1]

[0040]

[Table 2]

[0041]

EFFECT OF THE INVENTION The polyurethane elastic fiber wound body of the present invention has excellent homogeneity of various physical properties such as hot water resistance, and has a high density when it is subjected to high temperature dyeing or high temperature high pressure dyeing by knitting with nylon fibers or polyester fibers. Generation of spots, streaks, and streaks does not occur, and the feeling of power is sufficient. Therefore, it is possible to obtain a mixed knitted or dyed product with high added value.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Hirokazu Okuma, 1621 Sakazu, Kurashiki, Okayama Prefecture, Kuraray Co., Ltd.

Claims (2)

[Claims] 1. A polyurethane elastic fiber that is melt-spun and wound up, and has a relative viscosity difference between the innermost layer and the outermost layer of the wound body after heat aging of 0.10 to −0.10. A polyurethane elastic fiber wound body having a storage elastic modulus at 130 ° C. of 4.5 × 10 ⁷ dyne / cm ² or more in the innermost layer and the outermost layer of the wound body. 2. A polyurethane elastic fiber melt-spun and wound is subjected to a heat aging treatment under the conditions of a water content of 1000 ppm or less, a gas dew point of -20 to 25 ° C., and a temperature of 50 to 100 ° C. A method for producing a polyurethane elastic fiber wound body, which is characterized in that: