JPH06123008A - Polyurethane elastic fiber - Google Patents

Abstract

PURPOSE:To obtain a polyurethane elastic fiber excellent in chlorine resistance, light resistance and, in addition, in all properties of elastic recovery, heat resistance and hot water resistance, capable of high-temperature and high-pressure dyeing together with a polyester fiber and especially in strength elongation properties. CONSTITUTION:This polyurethane elastic fiber is characterized by constituting the fiber of a polyurethane obtained by polymerizing dicarboxylic acid components containing aromatic dicarboxylic acids in an amount of 10 to 60mol% based on the whole dicarboxylic acid components, a polymer diol satisfying the formula (I) mentioned below and exhibiting 1500 to 4000 molecular weight, an organic diisocyanate and a chain-lengthening agent, and satisfying the formulae (II) and (III) mentioned below: 5.1<= whole carbon aroms/number of ester bonding <=10.0...(I) 45%<=content of long chain hard segment <=70%... (II) retention of long chain hard segment content in melt heating >=85% (III).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyurethane elastic fiber which is capable of high-temperature and high-pressure dyeing, which is a dyeing condition for polyester fibers, and which is excellent in hot water resistance and excellent in elongation property. That is, the polyurethane elastic fiber of the present invention can be mixed not only with conventional nylon and cotton but also with polyester fiber.

[0002]

2. Description of the Related Art As a method for producing a polyurethane elastic fiber, a dry spinning method, a wet spinning method and a melt spinning method are known. Recently, polyurethane elastic fibers obtained by the melt spinning method have been attracting attention because of their ability to be finely denier, good transparency, and low cost. However, the polyurethane elastic fiber obtained by the melt-spinning method has an essential drawback that heat resistance, compared with the polyurethane elastic fiber obtained by the dry spinning method,
It is inferior in hot water resistance. Therefore, improvement of this heat resistance and hot water resistance has been a major issue for polyurethane elastic fibers obtained by the melt spinning method. The present inventors have proposed in JP-A-3-220311 a melt-spun polyurethane elastic fiber excellent in heat resistance and hot water resistance, which uses a polyester polymer diol having a side chain.

[0003]

According to the above method,
Although it is possible to obtain a certain level of performance at the laboratory level, it was difficult to secure sufficiently stable performance when attempting to carry out it on an industrial scale. The object of the present invention is excellent in chlorine resistance and light resistance and elastic recovery, heat resistance,
It is an object to provide a polyurethane elastic fiber which is excellent in all of hot water resistance, dyes at high temperature and high pressure at the same time as polyester fiber, and is particularly excellent in strength and elongation characteristics in an industrially stable manner.

[0004]

The present invention provides a polymeric diol (A), an organic diisocyanate (B) and a chain extender.
A polyurethane elastic fiber made of polyurethane obtained by polymerizing (C), wherein the polymer diol component (A) is a polyester diol having a molecular weight of 1500 to 4000 satisfying the following formula (I), and having the constitution: The component dicarboxylic acid contains aromatic dicarboxylic acid in an amount of 10 to 60 mol% with respect to the total dicarboxylic acid component, and the polyurethane constituting the elastic fiber satisfies the following relational expressions (II) and (III). It is a polyurethane elastic fiber characterized by the following. 5.1 ≦ total carbon number / ester bond number ≦ 10.0 (I) (The total carbon number is the carbon contained in the polymer diol excluding the carbon contained in the ester bond. 45% ≤ long-chain hard segment content rate ≤ 70% (II) (Here, the long-chain hard segment content rate means the polyurethane (A) that constitutes the elastic fiber. After the component was decomposed and removed with an alkali-methanol solution, the component composed of (B) and (C) and the component (A) linked to them with a urethane bond were taken out.
The ratio of the long chain hard segment in which the number of repeating units (B) and (C) is 3 or more with respect to all the hard segment constituent components consisting of the terminal diol component of (3) Melt heat retention rate of long chain hard segment content ≧ 85 % ………… (III) (Here, the melt heating retention ratio of the long-chain hard segment content means that the polyurethane that constitutes the elastic fiber is
Kneading in the molten state for 60 minutes and showing the change in long-chain hard segment content before and after that by the retention rate)

Polyurethane (A) constituting the elastic fiber,
Of the components (B) and (C), the hard segment components are
(B) and (C). However, the hard segment in the present invention means 0.01 NKO after swelling the polyurethane constituting the elastic fiber with a small amount of tetrahydrofuran (THF).
In a methanol solution of H at 50 ° C. under stirring for 7 days (A)
After completely decomposing the components, they were taken out (B) and (C).
A component containing a urethane bond and a terminal isocyanate group thereof reacts with the terminal diol of the component (A) and also contains a portion linked by a urethane bond. That is, it includes all compounds having an organic diisocyanate skeleton and its urethane bond after alkali decomposition under the above conditions. The long-chain hard segment content refers to the ratio of long-chain hard segments consisting of 3 or more repeating units of (B) and (C) to all the hard segments thus extracted.

In order to secure the heat resistance and hot water resistance of the elastic fiber, and to improve the elastic recovery property and the elongation, the content of the hard segment of the polyurethane should be decreased and the content of the long chain hard segment should be increased. is important. In the present invention, it is important that this ratio is 45% or more and 70% or less. If it is 45% or less, the properties such as heat resistance, hot water resistance and durability are significantly deteriorated. When it is 70% or more, the heat resistance is improved, but it becomes hard, the elongation and elastic recovery are low, the spinnability is lowered, and many problems occur in the processing step.

The melt heating retention of the long-chain hard segment content is 230 ° C. by plastograph (manufactured by Brabender) after dehydration of polyurethane constituting the elastic fiber.
After kneading in the molten state for 60 minutes, the long chain hard segment was taken out from the polyurethane before and after by the above alkali decomposition method, the content of the long chain hard segment was obtained, and the change is shown by the retention rate. Is.

When melt-spinning polyurethane, when the melt residence time is about 10 to 20 minutes, which is relatively short as in the pilot scale, even if elastic fibers excellent in heat resistance and hot water resistance are obtained, it is industrially used. When manufacturing elastic fibers on a large scale, the melt retention time is extended to about 40 to 60 minutes, which reduces fiber performance such as heat resistance and hot water resistance, and there is a large variation in quality and performance between yarn lots. It became clear. That is, in elastic fibers having a long-chain hard segment with a melt heat retention rate lower than 85%, even if the long-chain hard segment content is 45% or more by increasing the hard segment content of polyurethane, heat resistance and hot water resistance are increased. It was found that the yarn quality was not only poor, but also stiff, low in elongation, poor in elastic recovery, and the yarn quality varied.

As one means for achieving the relational expressions (II) and (III) of the present invention, there is a urethanization reaction rate constant of the polymer diol, and the polymer diol and 4,4'-diphenylmethane diisocyanate ( The apparent reaction rate constant (k) at 90 ° C. with MDI) is important. The long-chain hard segment content and the melt heating retention of the long-chain hard segment content are determined by the ester bond concentration in the polymer diol and the apparent reaction rate constant (k) of MDI of the polymer diol.

That is, if the catalyst used in the production of the polymeric diol, which is a raw material for polyurethane, is not completely deactivated, the long-chain hard segment content of the polyurethane decreases with time due to melt retention at high temperature. However, it was confirmed that the heat resistance and hot water resistance were also reduced. Therefore, the catalyst used during the production of the high molecular diol should be sufficiently deactivated,
The apparent reaction rate constant (k) between the polymer diol and 4,4′-diphenylmethane diisocyanate and the total number of carbon atoms / ester bond number (X) of the polymer diol are expressed by the following relational expression (IV) 0 ≦ k ≦ 0.0652X−0.152 ······················· (IV) by using a high-molecular diol, even if the melt residence time during polyurethane polymerization / spinning is a long time of 60 minutes or more, elastic yarn We have found that the quality and performance are stable. As a result, yarn unevenness and yarn breakage are greatly reduced, heat resistance and hot water resistance are improved, and high temperature processability during elastic fiber processing, high temperature dyeing stability due to disperse dyes, etc. are improved, and overall yarn The quality is greatly improved. This has made it possible to stably produce elastic fibers that can be mixed with polyester on an industrial scale.

In order for the above effects to be clearly and remarkably exhibited, the apparent reaction rate constant k is lowered and the molecular weight of the polymer diol is 1500 to 4000.
It was also clarified that the ester bond concentration was within the range of the present invention, that is, it was important to satisfy the formula (I). If the formula (I) is not satisfied, that is, (total carbon number / ester bond number) is smaller than 5.1, heat resistance and hot water resistance are lowered even if k is small. On the other hand, when it is more than 10, cold resistance, elastic recovery, elongation and spinnability deteriorate. Therefore, the elastic fiber of the present invention has a long-chain hard segment content of 85% or more even after melt kneading at 230 ° C. for 60 minutes. I am satisfied. That is, the apparent reaction rate constant
Polyurethanes using polymer diols in which (k) and polymer diol / ester bond number (X) do not satisfy formula (IV) have long-chain hard segment content decreased after melt spinning, and have heat resistance and hot water resistance. Is reduced.

The urethanization reaction rate is linearly proportional to the respective concentrations of hydroxyl groups and isocyanate groups. Therefore, the method for determining the apparent reaction rate constant in the present invention is
Polymeric diol and MDI were charged at a molar ratio of 3: 1, and 9
While maintaining the temperature at 0 ° C., stirring, a part of the reaction product was taken with the passage of time, and 1 / 100N di-n-butylamine DMF was added.
After a certain amount of the solution was added and dissolved, the residual amount of the isocyanate group was obtained by performing a neutralization titration with 1 / 100N hydrochloric acid in methanol using bromphenol blue as an indicator, and the following apparent second-order reaction rate constant was calculated. It was calculated according to the required formula. [1 / (ab)] · ln [b (ax) / a (bx)] = kt k: Reaction rate constant t: Reaction time (min) a: [OH] initial concentration b: [ NCO] initial concentration x: t [NHCOO] concentration at t

As a method for reducing the apparent reaction rate constant of the polymer diol, for example, 1.0 to 4.0% of water is added to the polymer diol, and the mixture is stirred at 80 to 150 ° C. for about 2 hours, 100 ° C. It can be carried out by stirring through steam at ˜150 ° C. or by adding a phosphorus compound generally used for deactivating the catalyst of polyester.

The molecular weight of these polymer diols is 1500 to 4 in order to improve heat resistance and hot water resistance.
The range of 000 is preferable, and 1800 or more is more preferable for further improving heat resistance and hot water resistance, and 3500 or less is more preferable for flexibility, elongation, elastic recovery and spinnability.

By using an aromatic dicarboxylic acid as the dicarboxylic acid used for the polymer diol, the strength of the elastic fiber is increased. It is important to use the aromatic dicarboxylic acid in an amount of 10 mol% or more, preferably 20 mol% or more, based on the total dicarboxylic acid components. If it exceeds 60 mol%, the strength increases but the elongation decreases. Examples of the aromatic dicarboxylic acid used in the polymer diol used in the present invention include isophthalic acid and terephthalic acid. From the viewpoint of cold resistance, isophthalic acid is particularly preferable.

Examples of the dicarboxylic acid which can be used in combination with the aromatic dicarboxylic acid include glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid and decanedicarboxylic acid. The diols used in the production of the polymeric diol include 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-
Octanediol, 1,9-nonanediol, 1,10
-Decanediol, 1,12-dodecanediol, 3-
Methyl-1,5-pentanediol, 2-methyl-1,
C4-C12 diols such as 8-octanediol may be used. These diols and dicarboxylic acids may be used alone, or two or more kinds of diols and dicarboxylic acids may be used in combination, as long as they satisfy the formula (I) of the present invention. In any case, if the (total carbon number / ester bond number) is less than 5.1, the heat resistance and hot water resistance are greatly reduced, and if it is more than 10, cold resistance, elastic recovery, elongation and spinnability are deteriorated.

When two or more kinds of polymer diols are used as the polymer diol, in addition to the case where the polymer diols are mixed and used, polyurethanes which are separately polymerized using the respective polymer diols are mixed and used. The case is also included in the scope of the present invention.

The method for producing the polyester diol used in the present invention is not particularly limited. For example, a method similar to the known method used in the production of polyethylene terephthalate or polybutylene terephthalate, that is, transesterification or direct esterification and It can be produced by the subsequent melt polycondensation reaction.

Suitable organic diisocyanates used in the present invention include aromatic, aliphatic or alicyclic diisocyanates, specifically 4,4'-diphenylmethane diisocyanate, p- Phenylene diisocyanate, toluylene diisocyanate, 1,5-
Examples thereof include diisocyanates having a molecular weight of 500 or less, such as naphthylene diisocyanate, xylylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, and 4,4′-dicyclohexylmethane diisocyanate. Preferred are 4,4'-diphenylmethane diisocyanate and / or p-phenylene diisocyanate.

In the present invention, the chain extender used is a chain growth agent commonly used in the polyurethane industry, that is, a low molecular weight compound having a molecular weight of 400 or less and containing at least two hydrogen atoms capable of reacting with an isocyanate, for example, Ethylene glycol, 1,4-butanediol, propylene glycol, 1,6-hexanediol, 3-
Methyl-1,5-pentanediol, 1,4-bis (2
Examples of diols include -hydroxyethoxy) benzene, 1,4-cyclohexanediol, bis- (β-hydroxyethyl) terephthalate, and xylylene glycol. These chain extenders may be used alone or in admixture of two or more. The most preferred chain extender is
1,4-butanediol and / or 1,4-bis (2-hydroxyethoxy) benzene.

As a method for polymerizing a polymeric diol, an organic diisocyanate and a chain extender to produce a polyurethane, a known urethanization reaction technique can be adopted. According to the research conducted by the present inventors, among others, it is preferable to perform melt polymerization in the substantial absence of an inert solvent, and particularly preferable is continuous melt polymerization using a multi-screw extruder. . The polyurethane used in the present invention consists essentially of a polymeric diol, an organic diisocyanate and a chain extender.

The polyurethane thus obtained is
A method in which pelletization is performed once and then melt spinning is performed, or a polyurethane obtained by melt polymerization is directly spun in a molten state through a spinneret can be adopted. From the viewpoint of spinning stability, polymerization direct binding spinning is preferable. When the polyurethane elastic fiber of the present invention is obtained by melt spinning, the spinning temperature is 250 ° C or lower, more preferably 200 ° C or higher and 235 ° C.
It is practical to spin below.

The polyurethane elastic yarn thus obtained can be used as a bare yarn as it is in actual use, or can be used as a coated yarn by being covered with other fibers. As the other fiber, conventionally known fibers such as polyamide fiber, wool, cotton and polyester fiber can be mentioned. Among them, polyester fiber is preferably used in the present invention.

Further, the polyurethane elastic fiber of the present invention is
Those containing 0.01% by weight or more of a dyeing type disperse dye are also included. As a method of incorporating a disperse dye, for example, polyurethane elastic fiber may be mixed with polyester fiber, and the disperse dye may be dyed at 110 to 130 ° C. Further, the polyurethane elastic fiber of the present invention is an epoch-making material in which the polyurethane elastic fiber is not cut even when dyed at 110 to 130 ° C., the heat resistance and the hot water resistance are good, and the good elasticity remains. Further, the polyurethane elastic fiber of the present invention has a great feature that it has very excellent dyeing fastness even when dyed in a light or dark color with a disperse dye.

Next, the disperse dye used in the present invention will be described. The disperse dye is used in order to obtain the same color property as that of the other fibers that are commonly used, and to prevent the eye blinding and enhance the color reproducibility. Quinone type and azo type are known as disperse dyes. The dyeing type disperse dye used in the present invention means that any one kind of polyurethane elastic yarn used in the present invention is dyed with 2% owf at 130 ° C. for 60 minutes for reduction washing. It is a dye that remains 40% by weight or more (measured from weight loss) after washing with water and drying.

That is, for any one type of polyurethane elastic yarn, dyeing is performed on the elastic yarn to determine whether it is a dyeing type disperse dye. Reduction cleaning conditions Hydrosulfide 3g / l Soda ash 2g / l Amylazine 1g / l Bath ratio 1:30 Temperature 80 ° C x 20 minutes

The polyurethane elastic yarn produced by the melt spinning method which is currently on the market has no resistance to high temperature and high pressure dyeing at 110 ° C. or higher and cannot be used together with polyester which requires high temperature and high pressure dyeing at least at 110 ° C. or higher. Also, 1
If the temperature is lower than 10 ° C, it is difficult to sufficiently darken the color or the dyeing fastness is poor. If there is nothing that can withstand high-temperature and high-pressure dyeing at 110 ° C or higher, it means that the high-temperature and high-pressure dyeing at 110 ° C or higher causes melting and loss of stretchability. In this respect, the ester polyurethane elastic fiber of the present invention is capable of high temperature and high pressure dyeing at 110 ° C. to 130 ° C. as described above, and thus has found a great combined effect that dyeing fastness is extremely excellent.

The polyurethane elastic fiber of the present invention makes it possible to mix the polyester elastic fiber which could not be mixed with the conventional polyurethane elastic yarn, and the coated elastic yarn made of polyester fiber which can be dyed at a high temperature and the cloth composed of the polyester fiber and the polyurethane elastic yarn. Can be done.

The following are examples of the fields of application in these industries. For clothing; swimwear, ski wear, cycling wear, leotards, lingerie, foundation, underwear. Miscellaneous goods: pantyhose, socks, supporters, hats, gloves, power nets, bandages. Non-clothing; gut for tennis racket, car seat ground yarn for integral molding, metal coated yarn for robot arm.

[0030]

The present invention will be described in detail below with reference to examples. The long-chain hard segment content, the melt heating retention rate of the long-chain hard segment content, the hot water resistance (stress = R), and the instantaneous elastic recovery rate ratio in the examples were measured by the following methods.

O Long-chain hard segment content 2 g of elastic thread was ultrasonically washed with 50 ml of n-hexane for 2 hours and dried, and then 1.50 g of the elastic thread was precisely weighed and THF was added.
Swell the sample by adding 5 ml. After 2 hours, 0.0
25 ml of 1N KOH in methanol was added,
The polymeric diol is completely decomposed under stirring for 7 days. After decomposition, the solvent is removed by evaporation within 2 hours at 50 ° C.
After putting in 000 ml of water, the precipitated hard segment is filtered with a filter paper. The thus-obtained hard segment was analyzed by GPC, and the content of the long-chain hard segment (hard segment having 3 or more repeating units consisting of an organic diisocyanate and a chain extender) with respect to all the hard segments (GPC peak area content) Rate).

O GPC analysis method of hard segment The hard segment taken out by the above method was thoroughly dried and homogenized, and 0.0200 g thereof was weighed and NMP 2.0 m
l and 6.0 ml of THF are added and dissolved. The following instruments and columns were used for GPC measurement. Shimadzu High Performance Liquid Chromatograph LC-9A Shimadzu Column Oven CTO-6A (40 ° C) Shimadzu High Performance Liquid Chromatograph Differential Refractometer Detector RI
D-6A Shimadzu Chromatopack C-R4A column Shodex GPC KF-802 Shodex GPC KF-802.5 20 μl sample (adjusted by injector) was measured, and the flow rate of the medium (THF) was 1.0 ml / min. For analysis after measurement, the area between the elution curve and the baseline is determined, and peaks that are not completely separated are vertically divided and processed. When two or more kinds of chain extenders or organic diisocyanates are mixed and used, a peak may have a shoulder portion, but usually the peak dividing treatment is not hindered.

Melt heating retention of long chain hard segment content Polyurethane elastic yarn was dried and dehydrated in vacuum at 90 ° C. for 24 hours, and then dried at 230 ° C. under a nitrogen atmosphere at 230 ° C. for 60 hours.
Kneading in a molten state for 1 minute, the hard segment was taken out from the polyurethane before and after the kneading by the above-mentioned alkali decomposition method, and the repeating unit among them showed a change in the content of long-chain hard segment of 3 or more in the retention rate. Is.

O Hot water resistance A sample (elastic yarn) was subjected to hot water treatment at 130 ° C for 30 minutes in a state of 200% elongation using a wooden frame, and the stress of 200% elongation was measured using an Instron. The stress is R (g /
dr)).

O Instantaneous elastic recovery rate ratio The instantaneous elastic recovery rates after 200% elongation at -10 ° C and 20 ° C were determined, respectively, and shown as the ratio. Instantaneous elasticity recovery means the reversion property immediately after removing stress by holding for 200 minutes after 200% elongation (applied JIS L-1096). Instantaneous elastic recovery rate = 100 × [nl− (l′−l)] / n
l (n is elongation ratio, l: initial length, l ′: length after stress removal, elongation and unloading speed is 500 mm / min) Instantaneous elastic recovery rate ratio = instantaneous elastic recovery rate at −10 ° C./20
Instantaneous elastic recovery rate at ℃

The compounds used are indicated by abbreviations, and the relationship between abbreviations and compounds is as shown in Table 1.

[Table 1]

Reference Example 1 (Production of Polyester Diol) Isophthalic acid 0.4 mol, adipic acid 0.6 mol and 1,
Esterification was carried out while distilling off water produced by condensation of 1.18 mol of 9-nonanediol at a temperature of about 195 ° C. while passing nitrogen gas under normal pressure. When the acid value of the polyester becomes about 10 or less, 20 ppm of tetraisopropyl titanate which is a catalyst is added to the polyester,
The degree of vacuum was gradually raised by a vacuum pump to carry out the reaction to obtain a polyester diol having an acid value of 0.2 and a molecular weight of 2000. After the temperature was lowered to 100 ° C., 3% of water was added to the produced polyester diol and stirred for 2 hours to deactivate the titanium catalyst. After deactivation, the added water was distilled off under reduced pressure to produce polyester diol A having a molecular weight of 2000. The apparent reaction rate constant between the produced polyester diol A and MDI at 90 ° C was 0.04 (l / l).
mol · min). The apparent reaction rate constant was determined according to the method described above.

Reference Example 2 A polyester diol having a molecular weight of 2000 was synthesized by the method described in Reference Example 1 except that the amount of water added for deactivating the titanium catalyst was 0.5% based on the produced polyester diol. The apparent reaction rate constant is 0.5 (l / mo
l · min) (polyester diol B)

Reference Examples 3 to 12 Polyester diols C to L were obtained in the same manner as in Reference Example 1 except that the acid component, the diol component and the amount of deactivated water were changed to those shown in Table 2. The apparent reaction rate constants are as shown in Table 2.

[0040]

[Table 2] X: total carbon number / carbonate bond number Water addition amount: wt% relative to polycarbonate diol

Example 1 Polyester diol A and 1,4-butane diol heated to 80 ° C. and M melted to 50 ° C.
DI was continuously supplied to a twin-screw extruder by a metering pump so as to have the composition shown in Table 3, and continuous melt polymerization was performed.
The produced polyurethane was extruded into water in a strand shape and cut into pellets. This pellet at 80 ℃
Vacuum dry for 20 hours, and spin at a spinning temperature of 215 ° C. and a spinning speed of 500 m / min with a conventional spinning machine equipped with a single-screw extruder.
An elastic yarn of 0 denier was obtained. The wound elastic yarn is aged at 80 ° C. for 20 hours under low humidity, and further at room temperature for 6 hours.
When aging was continued for 3 days in a humidity of 0% and various physical properties were measured, it was preferable as shown in Table 4. Further, this elastic yarn was decomposed with alkali, and the taken out hard segment was analyzed by GPC. The long-chain hard segment content and the melt heating retention of the long-chain hard segment were measured and are summarized in Table 4.

[0042]

[Table 3]

[0043]

[Table 4]

Examples 2 to 6 Polyurethanes having the compositions shown in Table 3 were synthesized in the same manner as in Example 1 and fed to the spinning head without pelletization,
Spinning was performed at 210 to 225 ° C. at a spinning speed of 500 m / min to obtain a polyurethane fiber having 80 denier / 2 filaments. These were aged under the same conditions as in Example 1, and various properties of the obtained elastic fiber were measured by the same method as in Example 1. The results were as favorable as in Example 1 as shown in Table 4.

Comparative Examples 1 to 6 In the same manner as in Example 1, polyurethane elastic fibers having the compositions shown in Table 3 were produced. As shown in Table 4, as compared with the polyurethane elastic fiber of the present invention, not only the hot water resistance but also the instantaneous elastic recovery rate and the elongation are very poor, and it is clear that it cannot be mixed with the polyester fiber.

[0046]

EFFECT OF THE INVENTION Since the polyurethane elastic fiber of the present invention can be dyed at 110 ° C. to 130 ° C. at high temperature and high pressure as described above, it can be mixed with the polyester fiber which could not be mixed with the conventional polyurethane elastic yarn, An elastic yarn covered with a polyester fiber which can be dyed at a high temperature and a fabric made of a polyester fiber and a polyurethane elastic yarn can be formed.
The polyurethane elastic yarn of the present invention is useful for the following applications. For clothing; swimwear, ski wear, cycling wear, leotards, lingerie, foundation, underwear miscellaneous goods: pantyhose, socks, supporters, hats, gloves, power nets, bandages, non-clothes; tennis racket gut, one piece Car seat ground yarn for molding, metal coated yarn for robot arm

Claims (2)

[Claims] 1. A polyurethane elastic fiber comprising polyurethane obtained by polymerizing a polymeric diol (A), an organic diisocyanate (B) and a chain extender (C), said polymeric diol component (A) Has a molecular weight of 1 which satisfies the following formula (I)
The dicarboxylic acid, which is a polyester diol of 500 to 4000 and its constituent component, contains an aromatic dicarboxylic acid in an amount of 10 to 60 mol% with respect to the total dicarboxylic acid component, and the polyurethane constituting the elastic fiber is as follows. I
Polyurethane elastic fiber characterized by satisfying the relational expressions (I) and (III). 5.1 ≦ total carbon number / ester bond number ≦ 10.0 (I) (The total carbon number is the carbon contained in the polymer diol excluding the carbon contained in the ester bond. 45% ≤ long-chain hard segment content rate ≤ 70% (II) (Here, the long-chain hard segment content rate means the polyurethane (A) that constitutes the elastic fiber. After the component was decomposed and removed with an alkali-methanol solution, the component composed of (B) and (C) and the component (A) linked to them with a urethane bond were taken out.
The ratio of the long chain hard segment in which the number of repeating units (B) and (C) is 3 or more with respect to all the hard segment constituent components consisting of the terminal diol component of (3) Melt heat retention rate of long chain hard segment content ≧ 85 % ………… (III) (Here, the melt heating retention ratio of the long-chain hard segment content means that the polyurethane that constitutes the elastic fiber is
Kneading in the molten state for 60 minutes and showing the change in long-chain hard segment content before and after that by the retention rate) 2. Apparent reaction rate constant (k) of polymeric diol and 4,4′-diphenylmethane diisocyanate (MDI) at 90 ° C. and total carbon number / ester bond number (X) of polymeric diol. The polyurethane elastic fiber according to claim 1, wherein a polymer diol satisfying the following relational expression (IV) is used. 0 ≦ k ≦ 0.0652X−0.152 (IV)