JPH05339817A - Polyurethane elastic fiber - Google Patents

Abstract

PURPOSE:To obtain a polyurethane elastic fiber excellent in chlorine fastness and lightfastness and also excellent in all of elastic recovery, heat resistance and hot water resistance and capable of being dyed at high temperature and high pressure with a polyester fiber at the same time. CONSTITUTION:This polyurethane elastic fiber is obtained by melt spinning a polyurethane obtained by polymerizing a polycarbonate diol containing an organic diisocyanate (B), a chain extender (C) and >=30 mole % 3-methyl-1,5- pentane diol based on the total diol component, satisfying the following relation I and having 2300-5000 molecular weight (M). The polyurethane of the elastic fiber satisfies the following relations of (II) and (III). (I) 5.1 <= number of the total carbon/number of the ester bonds <= 5.35. (II) 54% <= content of long chain hard segments having >= 3 number of repeating units of (B) and (C) <=75%. (III) content retention ratio of the long chain hard segment at melt heating >=80%.

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 having excellent hot water resistance and capable of high temperature and high pressure dyeing which is a dyeing condition for polyester fiber. 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 denilated, good transparency, and low cost, and the production volume has been increasing. 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 inventors of the present invention have proposed in JP-A-3-220311 a melt-spun polyurethane elastic fiber having excellent heat resistance and hot water resistance, which uses a polyester-prone molecular diol having a side chain. The elastic fiber described herein was intended to secure heat resistance, hot water resistance and the like by lowering the ester group concentration by using azelaic acid, sebacic acid or the like as the carboxylic acid component of the polyester diol.

[0003]

Although the above-mentioned polyester polyurethanes using azelaic acid and sebacic acid have some excellent performances, these acid components are expensive and the elastic fibers obtained are also expensive. It became expensive and there was a practical problem. The present invention uses a cheaper acid component such as adipic acid as a raw material, and has excellent chlorine resistance and light resistance and elastic recovery, heat resistance, and excellent hot water resistance,
It is to provide industrially stable polyurethane elastic fibers capable of dyeing at high temperature and high pressure at the same time as polyester fibers.

[0004]

The present invention relates to a polyurethane elastic fiber comprising polyurethane obtained by polymerizing polyester diol (A), organic diisocyanate (B) and chain extender (C). Polyester diol component
(A) satisfies the following formula (I) and has a molecular weight (M) of 2300 to 5
000 polyester diol, and the diol as a constituent thereof is a polyester diol containing 3-methyl-1,5-pentanediol in an amount of 30 mol% or more based on all diol components, and further constitutes an elastic fiber. The polyurethane elastic fiber is characterized in that the polyurethane satisfies the following relational expressions (II) and (III). 5.1 ≦ total carbon number / ester bond number ≦ 5.35 (I) (Here, the total carbon number is the remainder of the carbon contained in the polyester diol excluding the carbon contained in the ester bond. 54% ≤ long chain hard segment content ≤ 75% (II) (Here, the long chain hard segment content is the component (A) of the polyurethane that constitutes the elastic fiber. Was decomposed and removed with an alkali-methanol solution, and then taken out from the components composed of (B) and (C) and the components (A) linked to them with a urethane bond.
The ratio of the long chain hard segment in which the number of repeating units of (B) and (C) is 3 or more based on all the hard segment constituent components consisting of the terminal diol component of (4) Melt heat retention of long chain hard segment content ≧ 80 % ………… (III) (Here, the melt heating retention of the long-chain hard segment content is the polyurethane that constitutes the elastic fiber
Kneading in a molten state for 60 minutes and showing the change in the content of the long-chain hard segment 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 that the polyurethane constituting the elastic fiber is swollen with a small amount of tetrahydrofuran (THF), and
After completely decomposing the component (A) in a methanol solution of 50 ° C. under stirring for 7 days, the component containing the urethane bond composed of the components (B) and (C) and their terminal isocyanate groups are taken out. Includes a portion which reacts with the terminal diol of the component (A) and is 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 means 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. This ratio is 54
% And 75% or less is important. 54%
If it is below, the performance such as heat resistance, hot water resistance, and durability is significantly deteriorated. If it exceeds 75%, the heat resistance will improve,
Elongation and elastic recovery are low, and many problems occur in the processing process.

[0006] Further, the melt heating retention of the long chain hard segment content means that after the polyurethane constituting the elastic fiber is dehydrated, it is kneaded in a molten state for 60 minutes at 230 ° C with a Labo Plastomill (manufactured by Toyo Seiki Co., Ltd.). The long-chain hard segment content of the polyurethane before and after that was determined by the above-mentioned alkali decomposition method, and the change was shown as a retention rate.

In order to secure the heat resistance and hot water resistance of the elastic fiber, it is necessary to increase the content of the hard segment of polyurethane, but the content of the long chain hard segment is particularly important. At the same time, it is required that the long-chain hard segment content does not easily decrease during melt spinning. With elastic fibers having a long-chain hard segment retention of less than 80% by melting and heating, the heat resistance and hot water resistance are inferior even if the long-chain hard segment content is increased to 54% or more by increasing the hard segment content of polyurethane. In addition, they found that the yarn quality was stiff, had low elongation and poor elastic recovery, and the yarn quality varied. Especially, the elastic thread is 200
% In order to ensure the hot water resistance and the heat resistance after the residual stress R after hot water treatment at 130 ° C. for 30 minutes at 0.0075 g / dr or more, the long chain hard segment content is at least 54%. It is important that the melt heating retention of the long-chain hard segment content is 80% or more.

As one means for achieving the relational expressions (II) and (III) of the present invention, there is a urethane formation reaction rate constant of the polyester diol, and the polyester diol and 4,4'-diphenylmethane diisocyanate (MDI) 90 ℃ with
The apparent reaction rate constant (k) 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 polyester diol and the apparent reaction rate constant (k) of MDI of the polyester diol.

That is, if the catalyst used in the production of the polyester 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, At the same time, it was confirmed that the heat resistance and hot water resistance were decreasing. Therefore, the catalyst used during the production of the polyester diol was sufficiently deactivated, and the apparent reaction rate constant between the polyester diol and 4,4'-diphenylmethane diisocyanate
By using a polyester diol in which (k) and the molecular weight (M) of the polyester diol satisfy the relational expression 0 <k ≦ 0.0000588M-0.035 (IV),
It was found that the quality and performance of the elastic yarn are stabilized even when the melt residence time during polyurethane polymerization to spinning is a long time of 60 minutes or more. As a result, yarn unevenness and yarn breakage are greatly reduced, heat resistance and hot water resistance are improved, 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.
A polyurethane using a polyester diol that does not satisfy the relational expression (IV) has a low long-chain hard segment content after melt spinning, and has poor heat resistance and hot water resistance.

In order for the above effects to be clearly and remarkably exhibited, the apparent reaction rate constant is lowered and the molecular weight of the polyester diol is 2300 to 5000, and the ester bond concentration thereof is within the range of the present invention. That is, that is, that the formula (I) is satisfied and that the diol as a constituent component thereof is a polyester diol containing 3-methyl-1,5-pentanediol in an amount of 30 mol% or more based on all diol components. It became clear that it was important. If the content of 3-methyl-1,5-pentanediol is less than 30 mol% based on the total diol components, the elongation and the elastic recovery property at low temperature decrease.

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
Polyester diol and MDI were charged in a molar ratio of 3: 1 and stirred at 90 ° C. with stirring to take a part of the reaction product, and a certain amount of 1 / 100N di-n-butylamine DMF solution was added to dissolve it. After that, the residual amount of the isocyanate group was determined by performing neutralization titration with a methanol solution of 1/100 N hydrochloric acid using bromphenol blue as an indicator, and the following apparent second-order reaction rate constant was calculated according to the equation. [1 / (a-b)] · ln [b (a-x) / a (b-
x)] = kt k: Reaction rate constant t: Reaction time (minutes) a: [OH] initial concentration b: [NCO] initial concentration x: [NHCOO] concentration at t

As a method for reducing the apparent reaction rate constant of polyester diol, for example, water of 1.0 to 4.0% is added to polyester diol at 80 to 150 ° C.
It can be performed by stirring for about 2 hours, stirring at 100 ° C. to 150 ° C. through steam, or the like.

The molecular weight of these polyester diols is 2300 in order to improve heat resistance and hot water resistance.
The above is preferable, and 5000 or less is more preferable, and 4000 or less is more preferable from the viewpoint of elongation, elastic recovery, spinnability and the like.

The polyester diol used in the present invention is
A diol unit represented by the formula: —O—R ₁ —O— (wherein R ₁ represents a divalent organic group);

[Chemical 1] (Wherein R ₂ represents a divalent organic group) is a polyester diol having a dicarboxylic acid unit.

In order to improve heat resistance, hot water resistance, cold resistance, elastic recovery property, and melting heat retention of the long-chain hard segment content, 3-methyl-1,5-pentanediol is used as the above diol unit. Is required to be 30 mol% or more. As the diol used together with 3-methyl-1,5-pentanediol, 1,4-butanediol, 1,5-pentanediol, neopentyl glycol, 1,6-hexanediol, 1,7-heptanediol, 1 , 8-octanediol, 2-methyl-1,8-octanediol, 1,9-nonanediol,
Examples thereof include diols having 4 to 11 carbon atoms such as 1,10-decanediol.

Aliphatic dicarboxylic acids are preferred as the compound giving the dicarboxylic acid unit, and adipic acid is particularly preferred. If it is 50 mol% or less, there is no problem even if a dicarboxylic acid such as a saturated aliphatic or aromatic dicarboxylic acid having 5 to 12 carbon atoms is copolymerized. Specific examples thereof include glutaric acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, decanedicarboxylic acid, isophthalic acid and terephthalic acid. In any case, it is essential that the combination of diols is in the range of 5.1 ≦ total carbon number / ester bond number ≦ 5.35, and if it is less than 5.1, heat resistance and hot water resistance are deteriorated. When it is larger than 5.35, the elastic recovery property at low temperature, the elongation and the spinnability are extremely deteriorated and the yarn breaks frequently. Preferably, 5.2 ≦ total carbon number / ester bond number ≦ 5.3.

When two or more types of polyester diols are used as the polyester diol, the present invention is applicable not only when the polyester diols are mixed but also when the polyurethanes separately polymerized using the respective polyester diols are mixed and used. It is included in the range of.

The polyester diol used in the present invention can be obtained, for example, by a method similar to the known method used in the production of polyethylene terephthalate or polybutylene terephthalate, that is, transesterification or direct esterification followed by melt polycondensation reaction. It can be manufactured.

Suitable organic diisocyanates used in the present invention include aromatic, aliphatic or alicyclic diisocyanates, specifically 4,4'-diphenylmethane diisocyanate, p- Molecular weight of phenylene diisocyanate, toluylene diisocyanate, 1,5-naphthylene diisocyanate, xylylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, etc. 500 or less The diisocyanate of is illustrated. Preferred is 4,4'-diphenylmethane diisocyanate.

The chain extender used in the present invention 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 thereof include diols such as 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.

Regarding the method for polymerizing the polyester diol, the organic diisocyanate and the chain extender to produce polyurethane, a known urethanization reaction technique can be adopted. According to the research conducted by the present inventors, among others, it is preferable that the melt polymerization is carried out in the substantially absence of an inert solvent, and particularly, the continuous melt polymerization using a multi-screw extruder is preferable. .. The polyurethane used in the present invention is substantially composed of (a) a polyester diol, a divalent structural unit in which two hydrogen atoms in hydroxyl groups at both terminals of the molecule are removed,

(B) General formula derived from organic diisocyanate

[Chemical 2] (In the formula, R ₃ is a divalent organic group.) Two hydrogen atoms capable of reacting with the organic diisocyanate at both ends of the molecule of the chain extender (c) are removed. It consists of a divalent structural unit of shape. Here, the structural units of (a) and (c) form a urethane bond with the structural unit of (b), and some of the structural units of (b) are other structural units of (b). It is considered that there is a case in which an alohanate bond is formed with a part of.

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 through a spinneret in a molten state 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 is used as it is as a bare yarn in actual use, or is covered with another fiber to be used as a coated yarn. As the other fiber, conventionally known fibers such as polyamide fiber, wool, cotton and polyester fiber can be mentioned. Among them, polyester fiber is used in the present invention.

Further, the polyurethane elastic fiber of the present invention is
It also includes those containing 0.01% by weight or more of a dyeing type disperse dye. As a method of containing a disperse dye, for example, polyurethane elastic fiber may be mixed with polyester fiber and dyed with a disperse dye 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 does not cut even when dyed at 110 to 130 ° C., has good heat resistance and hot water resistance, and retains good elasticity. Further, the polyurethane elastic fiber of the present invention has a great feature that the dyeing fastness is very excellent even when dyed with a disperse dye in a light color or a dark color.

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 blinding and improve 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. After being washed with water and dried, 40% by weight or more (measured from weight loss) of the dye remains.

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

Polyurethane elastic yarns obtained by the melt spinning method which are currently on the market have 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 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. Nothing that can withstand high-temperature and high-pressure dyeing at 110 ° C. or higher 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 polyester elastic fibers which could not be mixed with conventional polyurethane elastic yarns, and is coated with polyester fibers which can be dyed at high temperature, and a cloth composed of polyester fibers and polyurethane elastic yarns. Can be done. The fields of application in these industries include the following. 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 yarn was ultrasonically washed with 50 ml of n-hexane for 2 hours and dried, and then 1.50 g of the elastic yarn was precisely weighed and THF was added.
Swell the sample by adding 5 ml. 2 hours later, 0.0
Add 25 ml of 1N KOH in methanol and
The polyester diol is completely decomposed under stirring for 5 days. After the decomposition, the solvent is removed by evaporation within 2 hours at 50 ° C., the mixture is further put into 1000 ml of water, and 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) 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 out, and NMP of 2.0 ml,
Dissolve by adding 6.0 ml of THF. 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. In the analysis after the measurement, the area between the elution curve and the baseline is obtained, and the peaks that are not completely separated are vertically divided and processed as shown in FIG. When two or more kinds of chain extenders or organic diisocyanates are mixed and used, a shoulder portion may occur at each peak, but usually the peak dividing treatment is not hindered.

O Melting heat retention of long chain hard segment content The melting heat retention of long chain hard segment content means the polyurethane elastic yarn obtained by ultrasonically washing 100 g of elastic fiber with 5000 cc of n-hexane for 10 minutes. 90 g to 90 ° C
After drying and dehydration in a vacuum for 24 hours, the mixture was kneaded in a molten state at 230 ° C. for 60 minutes in a Labo Plastomill (manufactured by Toyo Seiki Co., Ltd.) under a nitrogen atmosphere, and the polyurethane before and after kneading was treated with the same alkali decomposition method as above. The hard segment was taken out according to, and the change in the content of the long-chain hard segment having the number of repeating units of 3 or more is shown by the retention rate.

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

O Instantaneous elastic recovery rate ratio The instantaneous elastic recovery rates after 200% elongation at -10 ° C and 20 ° C were obtained, and the ratios were obtained. Instantaneous elastic recovery means a 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 ratio ratio = instantaneous elastic recovery at -10 ° C / 20
Instantaneous elastic recovery at ℃

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

[Table 1] Abbreviation Compound EG Ethylene glycol BD 1,4-butanediol HD 1,6-hexanediol MPD 3-Methyl-1,5-pentanediol AD Adipic acid MDI 4,4′-diphenylmethane diisocyanate

Reference Example 1 (Production of polyester diol) MPD 1416 g and adipic acid 1460 g (MPD / A
Esterification was carried out while distilling off water produced by condensation at a temperature of about 200 ° C. while passing nitrogen gas at a molar ratio of D = 1.2 / 1) under normal pressure. Acid value of polyester is about 10
When the amount became the following, 20 ppm of tetraisopropyl titanate as a catalyst was added to the polyester, the degree of vacuum was gradually raised by a vacuum pump to carry out the reaction, and an acid value of 0.
2, polyester diol having a molecular weight of 2500 was obtained. After the temperature was lowered to 100 ° C., 3% of water was added to the produced polyester diol and stirred for 2 hours,
The titanium catalyst was deactivated. After deactivation, the added water was distilled off under reduced pressure to produce polyester diol A having a molecular weight of 2500 and an acid value of 0.2. The apparent reaction rate constant of the produced polyester diol A and MDI at 90 ° C. is 0.0
It was 5 (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 2500 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 0.55 (l / m
ol · min) (polyester diol B)

Reference Examples 3 to 8 Except that the diol components shown in Table 2 were used,
Polyester diols C to H were obtained in the same manner as in Reference Example 1. 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 each heated to 80 ° C. and M heated to 50 ° C.
DI and DI were 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 resulting 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 using a conventional spinning machine equipped with a single-screw extruder, and
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,
When aging was continued for 3 days under a humidity of 60% and various physical properties were measured, it was preferable as shown in Table 3.
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 3.

[0042]

[Table 3]

The hard segment chain length distribution (GPC chart) of the obtained elastic fiber is shown in FIG. Each peak number in the figure is the basic component of the hard segment 4,
It is the number of repetitions of 1,4-butanediol (BD) bound to 4'-diphenylmethane diisocyanate (MDI), and the peak of 5 includes those having a number of repetitions of 5 or more. That is, the hard segment structures of the peaks indicated by 0 to 5 in the figure are as follows. 0: MPD-MDI-MPD (n = 0) 1: MPD- (MDI-BD) ₁ -MDI-MPD (n = 1) 2: MPD- (MDI-BD) ₂ -MDI-MPD (n = 2) 3: MPD- (MDI-BD) ₃ -MDI-MPD (n = 3) 4: MPD- (MDI-BD) ₄ -MDI-MPD (n = 4) 5: MPD- (MDI-BD) _n -MDI -MPD (n ≧ 5) The peak area fraction (%) of the hard segment chain length distribution of the elastic fiber is And the long chain hard segment content (%) is 40+
It is 12 + 14 = 66 (%).

Examples 2 to 4 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.

Comparative Examples 1 to 4 In the same manner as in Example 1, polyurethane elastic fibers having the compositions shown in Table 3 were produced. Two or more of hot water resistance, instantaneous elastic recovery rate, and elongation are inferior to the polyurethane elastic fiber of the present invention.

Example 5 The elastic fiber obtained in Example 1 was knitted by a 20 gauge tubular knitting machine and dyed under the following conditions. Scouring Relax: 80 ° C x 1 min Dyeing machine: Drum dyeing machine Dye: Sumikaron Red E-RPD (Quinone-based Sumitomo Chemical Co., Ltd.) 2.0% owf Dispersion aid: Disper TL (Meisei Chemical Co., Ltd.) 1 g / l PH adjuster: Ammonium sulfate 1 g / l Acetic acid 1 g / l Bath ratio: 1:30 Temperature: Temperature rise from 40 ° C. to 130 ° C. over 30 minutes and maintain at 130 ° C. for an additional 30 minutes Reduction cleaning Reducing agent composition: Hydrosulfide 3 g / L soda ash 2g / l amylazine (Daiichi Pharmaceutical Co., Ltd.) 1g / l Bath ratio: 1:30 Temperature: 80 ° C x 20 minutes

Then, after thoroughly washing with water and drying, the dyeing fastness was measured. As a result, all the dyeing fastnesses measured as follows were good, and all of the 3rd grades, which are usually required for clothing, were cleared, and it was very good. Washing fastness (JIS L-0844A2 method): Level 4
(Pollution) Water fastness (JIS L-0846B method): Grade 4
(Staining) Sweat fastness (JIS L-0848A method): Grade 4
(Pollution) Light fastness (JIS L-0842 Carbon Arc No. 3
Exposure method): Grade 4 to 5 The power feeling of this fabric was also good.

Examples 6 to 8, Comparative Examples 5 to 8 The elastic fibers obtained in Examples 2 to 4 and Comparative Examples 1 to 4 were dyed in the same manner as in Example 5 to evaluate the dyeing fastness and the feeling of power. The results are shown in Table 4. The comparative examples are inferior to the polyurethane elastic fiber of the present invention in dyeing fastness and power feeling of the fabric.

[0049]

[Table 3]

[0050]

As described above, the polyurethane elastic fiber of the present invention can be dyed at 110 ° C. to 130 ° C. under high temperature and high pressure, and thus can be mixed with a polyester fiber which could not be mixed with a 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 thread for molding, metal coated thread for robot arm

[Brief description of drawings]

FIG. 1 is an example (of Example 1) of a hard segment chain length distribution (GPC chart) of an elastic fiber according to the present invention.

[Explanation of symbols]

0 The peak where the number of BD repeats bound to MDI, which is the basic constituent of the hard segment, is 0 (structural unit MPD-M
(Equivalent to DI-MPD) 1 Peak with 1 repeat number of BD bound to MDI which is a basic constituent of hard segment (structural unit MPD-
(Equivalent to (MDI-BD) ₁ -MDI-MPD) 2 Peak of 2 repeats of BD bound to MDI which is a basic constituent of hard segment (structural unit MPD-
(Equivalent to (MDI-BD) ₂ -MDI-MPD) 3 Peak with 3 repeats of BD bound to MDI which is the basic constituent of hard segment (Structural unit MPD-
(Equivalent to (MDI-BD) ₃ -MDI-MPD) 4 Peak with 4 repeats of BD bound to MDI which is the basic constituent of hard segment (Structural unit MPD-
(Equivalent to (MDI-BD) ₄ -MDI-MPD) 5 Peaks in which the number of BD repeats bound to MDI, which is the basic constituent of the hard segment, is 5 or more (structural unit M
PD- (MDI-BD) _n -MDI-MPD (n ≧ 5) equivalent)

[Table 4]

Claims (2)

[Claims] 1. A polyurethane elastic fiber comprising polyurethane obtained by polymerizing a polyester diol (A), an organic diisocyanate (B) and a chain extender (C),
The polyester diol component (A) is a polyester diol having a molecular weight (M) of 2300 to 5000 satisfying the following formula (I), and the diol as a constituent thereof is 3-
A polyester diol containing methyl-1,5-pentanediol in an amount of 30 mol% or more based on all diol components, and further, a polyurethane constituting an elastic fiber is
A polyurethane elastic fiber characterized by satisfying the relational expressions (II) and (III). 5.1 ≦ total carbon number / ester bond number ≦ 5.35 (I) (Here, the total carbon number is the remainder of the carbon contained in the polyester diol excluding the carbon contained in the ester bond. 54% ≤ long chain hard segment content ≤ 75% (II) (Here, the long chain hard segment content is the component (A) of the polyurethane that constitutes the elastic fiber. Was decomposed and removed with an alkali-methanol solution, and then taken out from the components composed of (B) and (C) and the components (A) linked to them with a urethane bond.
The ratio of the long chain hard segment in which the number of repeating units of (B) and (C) is 3 or more based on all the hard segment constituent components consisting of the terminal diol component of (4) Melt heat retention of long chain hard segment content ≧ 80 % ………… (III) (Here, the melt heating retention of the long-chain hard segment content is the polyurethane that constitutes the elastic fiber
Kneading in a molten state for 60 minutes and showing the change in the content of the long-chain hard segment before and after that by the retention rate) 2. The apparent reaction rate constant (k) of polyester diol with 4,4′-diphenylmethane diisocyanate (MDI) at 90 ° C. and the molecular weight (M) of polyester diol are expressed by the following relational expression (IV): 2. A polyurethane elastic fiber according to claim 1, wherein a polyester diol satisfying the condition (1) is used. 0 <k ≦ 0.0000588M-0.035 ………… (IV)