JPH11323659A - Polyamide-based elastic fiber, its production, and woven or knitted fabric - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a polyamide-based elastic fiber capable of being produced by a melt spinning, and capable of providing a woven or knitted fabric having good elastic characteristics and dimensional stability. SOLUTION: This polyamide-based elastic fiber is composed of a polyamide elastomer having a hard segment derived from a polyamide, and a soft segment derived from a poly(alkylene oxide)glycol and/or poly(alkylene oxide)diamine, having 500-4,000 number average molecular weight, and produced by carrying out a chain extension of both segment by a 4-10C dicarboxylic acid, and containing 5-40 wt.% hard segment. The polyamide-based elastic fiber has >=90% elastic recovery after 100% elongation, <=4×10<-2> cN/dtex shrinking stress in dry heat, 1×10<-2> -5×10<-2> cN/dtex recovery stress at 60% elongation and <=60% hysteresis loss.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a polyamide-based elastic fiber, a method for producing the same, and a woven or knitted fabric. More specifically, a polyamide-based elastic fiber having good elastic properties obtained by melt-spinning a polyamide elastomer comprising a hard segment derived from polyamide, a soft segment derived from poly (alkylene oxide) glycol and / or poly (alkylene oxide) diamine, and The present invention relates to a method for producing the same and a woven or knitted fabric made of such elastic fibers.

[0002]

2. Description of the Related Art Conventionally, spandex (polyurethane elastic fiber) has been used in a wide range of applications from apparel to industrial materials because of its high elastic properties as an elastic fiber. Spandex is manufactured by a dry spinning method, a wet spinning method, and a melt spinning method. Of these, dry spinning,
Wet spinning can provide high-quality spandex with excellent elastic properties, but requires complicated equipment. On the other hand, in the melt spinning method that is simple and has high productivity, a low melting point polyurethane is used because the spinning temperature needs to be set to be equal to or lower than the urethane bond decomposition temperature. for that reason,
Only elastic fibers with low elastic properties can be obtained.

[0003] Also, Japanese Patent Application Laid-Open No. 61-289118,
JP-A-61-289119, JP-A-61-289
No. 120 discloses a polyamide-based elastic fiber which can be melt-spun and has excellent elastic properties. In that publication,
An undrawn yarn obtained by melt-spinning a polymer using nylon 6, nylon 12 or nylon 66 for the hard segment and poly (alkylene oxide) glycol for the soft segment, and an elastic fiber obtained by drawing or heat-relaxing the drawn or undrawn yarn. I have.

[0004] However, the undrawn yarn disclosed in this publication has insufficient elastic properties, and the elongation recovery rate deteriorates when used repeatedly. In the case of drawn yarn, after weaving and knitting,
Although the elastic properties are developed by the heat treatment, the elastic fibers greatly shrink during the heat treatment, so that only a low-grade woven or knitted material having poor dimensional stability can be obtained. Furthermore, even if the elastic fiber is subjected to a relaxation heat treatment after stretching, the elastic fiber shrinks greatly during the heat treatment, so that not only can a low-quality woven or knitted fabric with poor dimensional stability be obtained, but also after spinning, winding, stretching, and relaxation. It is obtained by two steps of heat treatment, and there is a problem in terms of productivity.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a polyamide-based elastic fiber which can be produced by melt spinning and has good elastic properties and dimensional stability when formed into a woven or knitted fabric. .

[0006]

In order to solve the above-mentioned problems, the polyamide elastic fiber of the present invention mainly has the following constitution. That is, a hard segment derived from polyamide,
It has a soft segment derived from poly (alkylene oxide) glycol and / or poly (alkylene oxide) diamine having a number average molecular weight of 500 to 4000, is chain-extended by a dicarboxylic acid having 4 to 10 carbon atoms, and has a weight ratio of a hard segment. Is a polyamide-based elastic fiber comprising a polyamide elastomer having 5 to 40%,
100% elongation recovery rate is 90% or more, dry heat shrinkage stress is 4 ×
10 ^-2 cN / dtex or less, 60% recovery stress is 1 × 10
^{-2 to} 5 × 10 ^-2 cN / dtex, hysteresis loss is 6
It is a polyamide-based elastic fiber characterized by being 0% or less.

The method for producing a polyamide elastic fiber of the present invention mainly has the following constitution. That is, polyamide-derived hard segments, number average molecular weight of 500 to 40
00 poly (alkylene oxide) glycol and / or
Alternatively, a polyamide elastomer having a soft segment derived from poly (alkylene oxide) diamine, chain-extended with a dicarboxylic acid having 4 to 10 carbon atoms, and having a hard segment weight ratio of 5 to 40% is obtained by melt spinning. A method for producing a polyamide-based elastic fiber, characterized in that the undrawn yarn is heat-treated in a relaxed or fixed-length state at a temperature of 40 ° C. or more and 10 ° C. or less lower than the polymer melting point (Tm).

Further, the woven or knitted fabric of the present invention mainly has the following constitution. That is, having a hard segment derived from polyamide, a soft segment derived from poly (alkylene oxide) glycol and / or poly (alkylene oxide) diamine having a number average molecular weight of 500 to 4000,
A polyamide-based elastic fiber made of a polyamide elastomer having a chain extension of 4 to 10 carbon atoms and a weight ratio of a hard segment of 5 to 40%, and a 100% elongation recovery rate of 90% or more, At least a part of polyamide-based elastic fiber having a heat shrinkage stress of 4 × 10 ^-2 cN / dtex or less, a 60% recovery stress of 1 × 10 ^{-2 to} 5 × 10 ^-2 cN / dtex and a hysteresis loss of 60% or less. A woven or knitted fabric characterized by being used for:

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The poly (alkylene oxide) glycol constituting the soft segment of the polyamide elastomer according to the present invention includes poly (ethylene oxide) glycol, poly (propylene oxide) glycol, poly (tetramethylene oxide) glycol and poly (tetramethylene oxide) glycol. Hexamethylene oxide) glycol and copolymers thereof are exemplified. Among them, poly (tetramethylene oxide) glycol is preferably used in view of heat resistance, water resistance, mechanical strength, and elastic properties.

The polyalkylene oxide glycol has a number average molecular weight of 500 to 4,000, preferably 600 to 2,000. When the number average molecular weight is less than 500, the elongation recovery rate of the elastic fiber obtained is insufficient. On the other hand, when it exceeds 4,000, the compatibility decreases during polymerization and a uniform polymer cannot be obtained.

As the poly (alkylene oxide) diamine having a number average molecular weight of 500 to 4000, hydrogen of a hydroxyl group (-OH) at both ends of the above-mentioned compound of poly (alkylene oxide) glycol is converted to an aminoalkyl group (- RNH ₂ ). In addition,
R means an alkylene group having 2 or more carbon atoms.

In the present invention, a dicarboxylic acid having 4 to 10 carbon atoms is used as a chain extender. A dicarboxylic acid having less than 4 carbon atoms has a problem in hydrolysis resistance, while a dicarboxylic acid having more than 10 carbon atoms has a problem in light resistance. In addition, chain extenders other than dicarboxylic acids have a problem in mechanical properties at high temperatures.

Examples of such dicarboxylic acids include terephthalic acid, isophthalic acid, 1,4-cyclohexanedicarboxylic acid, adipic acid, and sebacic acid. Among them, dicarboxylic acids such as terephthalic acid and adipic acid can be used to obtain elastic fibers. Are preferably used in terms of color tone and physical characteristics.

The weight ratio of the hard segment of the polyamide elastomer obtained by copolymerizing these components is 5 to 40.
%, Preferably 10 to 30%. If the weight ratio of the hard segment is less than 5%, the melting point of the polymer becomes too low, and the heat resistance deteriorates. On the other hand, when the weight ratio is 4
If it exceeds 0%, the flexibility and elastic properties will be reduced.

The polyamide which is the hard segment of the present invention includes nylon 6, nylon 66, nylon 6
10, nylon 10, nylon 11, nylon 12, and the like. Of these, nylon 6, nylon 66, or nylon 12 is preferable.

The polyamide elastic fiber of the present invention is 100%
The elongation recovery rate is 90% or more, preferably 95% or more. If the 100% elongation recovery rate is less than 90%, the recovery when the elastic fiber is woven and knitted and repeatedly elongated is insufficient.

Further, the polyamide elastic fiber of the present invention has a dry heat shrinkage stress of 4 × 10 ⁻² cN / dtex or less, preferably 3 × 10 ⁻² cN / dtex or less.
When the dry heat shrinkage stress exceeds 4 × 10 ^-2 cN / dtex,
For example, when a woven or knitted fabric using a covering yarn covered with nylon yarn with elastic fibers as the core yarn is heat-treated during heat setting at the time of dyeing or finishing, it shrinks greatly, resulting in poor dimensional stability as well as texture hardening. Also occurs. By setting the dry heat shrinkage stress to 4 × 10 ^-2 cN / dtex or less, the elastic fiber shrinks only to the same degree as the nylon fiber due to the restraining force due to the covering in the heat treatment step, so that the elastic properties and dimensional stability are stable. A stretch woven or knitted fabric having good properties and texture can be obtained.

The polyamide elastic fiber of the present invention has a 60% recovery stress of 1 × 10 ^{-2 to} 5 × 10 ^-2 cN / dtex, preferably 2 × 10 ^-2 to 4 × 10 ^-2 cN / dtex. Is what you do. In the present invention, the 60% recovery stress is
When the elastic fiber is stretched by 100% and then restored to the original test length position, it refers to the stress at the elongation of 60% of the curve at the time of restoration. 60% recovery stress is 5 × 10 ^-2 cN / dtex
When wearing a woven or knitted fabric using the elastic fiber,
I feel a strong sense of oppression because of the strong tension. In addition, 60%
When the recovery stress is less than 1 × 10 ⁻² cN / dtex, when a woven or knitted fabric using the elastic fiber is worn, the tightening force is reduced due to weak tension.

Further, the polyamide elastic fiber of the present invention has a hysteresis loss of 60% or less, preferably 50% or less. In the present invention, the hysteresis loss means that after elongating the elastic fiber by 100%, the elastic fiber is restored to the original test length position, a hysteresis curve is drawn, and the area sandwiched between the curve at the time of elongation and the curve at the time of recovery. Means the ratio between the curve at the time of elongation and the area sandwiched between the horizontal axis (axis of elongation). If the hysteresis loss is 60% or more, energy is greatly lost due to the destruction of the aggregated structure of the hard segments due to elongation. For this reason, when it is repeatedly used, the elongation recovery rate is deteriorated, and the elastic fiber becomes fully expanded, so that it cannot be used.

The polymerization method for producing the polyamide elastomer used in the present invention is not particularly limited. For example, a polyamide component, a poly (alkylene oxide) glycol component and a dicarboxylic acid are charged into a reaction vessel and reacted at a high temperature to terminate both ends. There is a method in which a polyamide prepolymer of carboxylic acid is prepared, and poly (alkylene oxide) glycol is reacted with the prepolymer under vacuum.

Further, in order to improve the heat resistance and weather resistance of the polymer, additives such as an antioxidant and a light stabilizer may be used alone or in combination of two or more.

In the method for producing a polyamide-based elastic fiber of the present invention, the unstretched yarn obtained by melt-spinning and winding the above-mentioned specific polyamide elastomer is subjected to 40
℃ or more, below 10 ° C below the polymer melting point (Tm),
Preferably 60 ° C. or higher, 20 ° C. below the polymer melting point (Tm)
Heat treatment in a relaxed or fixed-length state at a low temperature or lower. Here, the polymer melting point (Tm) means, of course, the melting point of the polyamide elastomer. By performing heat treatment in a relaxed or fixed-length state, microcrystals are generated in the fiber structure, and the cohesive structure of the hard segments is strengthened during elongation, so that the elastic properties can be improved as compared with the elastic fiber that has not been heat-treated. It is. On the other hand, when the temperature of the heat treatment is lower than 40 ° C., there is a problem that the formation of microcrystals in the fiber structure becomes insufficient.
If the temperature exceeds 10 ° C. lower than m), there is a problem that elastic fibers are welded and yarn breakage occurs.

Further, in the production method of the present invention, the relaxation rate when the undrawn elastic fiber yarn is heat-treated in a relaxed state is preferably 40% or less, more preferably 30% or less. By setting the relaxation rate to 40% or less, the process stability is improved, and the occurrence of yarn breakage can be effectively suppressed.

In the production method of the present invention, the spinning speed is 8
It is preferable to perform melt spinning at a relatively low speed of not more than 00 m / min, and more preferably not more than 500 m / min. By spinning at such a low speed, the orientation of the elastic fiber can be suppressed, and an elastic fiber having good elastic properties can be obtained. Further, in the method for producing an elastic fiber of the present invention, after the undrawn yarn is once wound as described above, the heat treatment is not limited to the two-step method. A one-step method of performing a heat treatment may be used.

[0025]

Next, the present invention will be described specifically with reference to examples. The yarn physical properties of the elastic fiber were measured by the following method.

(1) Elongation recovery rate Sample length 2 cm, tensile speed 2 by Tensilon tensile tester
After 100% elongation at 0 cm / min, the sample is left for 1 minute, recovered at the same speed to the original test length position, a hysteresis curve is drawn as shown in FIG. 1, and the length at 100% elongation (S0),
The length (S1) when the stress became 0 was determined, and the elongation recovery rate was determined by the following equation.

Elongation recovery rate (%) = (S0−S1) / S0 × 100 S0: Length at 100% elongation S1: Length when stress becomes 0 (2) Dry heat shrinkage stress Multifilament Take a single 10cm scalpel,
An initial load of 1.4 × 10 ⁻² cN / dtex was applied, the shrinkage stress was measured in a temperature range from room temperature to 200 ° C., and the maximum stress was taken as dry heat shrinkage stress.

(3) 60% recovery stress Sample length 2 cm, tensile speed 2 using a Tensilon tensile tester
After elongating 100% at 0 cm / min, it was restored to the original test length position at the same speed, a hysteresis curve was drawn as shown in FIG. 1, and the curve was obtained from the stress at 60% elongation at the time of recovery.

(4) Hysteresis loss A sample length of 2 cm and a tensile speed of 2 were measured with a Tensilon tensile tester.
After 100% elongation at 0 cm / min, it was restored to the original test length position at the same speed, a hysteresis curve was drawn as shown in FIG. 1, and the area interposed between the elongation curve and the recovery curve From (A ₁ ) and the area (A ₁ + A ₂ ) interposed between the curve at the time of elongation and the horizontal axis (axis of elongation), the hysteresis loss was determined by the following equation.

Hysteresis loss (%) = ｛A ₁ / (A ₁ +
A ₂ )｝ × 100 (Example 1, Comparative Example 1) 26.3 parts by weight of ε-caprolactam, 5.5 parts by weight of adipic acid, number average molecular weight 2,000
Of poly (tetramethylene oxide) glycol 75.2
Parts by weight, "Irganox 1098" (antioxidant)
After 0.5 part by weight was charged and reacted at 230 ° C. for 2 hours in a nitrogen atmosphere under normal pressure, the temperature was raised to 250 ° C., and polymerization was carried out at 1 mmHg or less for 3 hours. Relative viscosity (ηr) of the obtained polymer (orthochlorophenol 0.5
%, Measurement temperature 25 ° C) was 2.19, and the melting point by DSC was 178 ° C.

This polymer was melt-spun at a spinning temperature of 220 ° C. and wound at 400 m / min to obtain an undrawn yarn of 44 dtex and 3 filaments. Table 1 shows the physical properties of the obtained undrawn yarn.
(Comparative Example 1). The fiber has a 100% elongation recovery rate of 8
As low as 7%, the elastic properties were insufficient. On the other hand, a relaxation heat treatment was performed at a relaxation rate of 20% while the undrawn yarn was in contact with a hot plate at 70 ° C. Table 1 shows the physical properties of the obtained relaxed heat-treated yarn (Example 1). When the fiber was cross-knitted with a nylon fiber to form a stocking, it was found to be a product having an appropriate tightening feeling and a good texture, and also having excellent recoverability upon repeated use.

[0032]

[Table 1] Comparative Example 2 The physical properties of a drawn yarn obtained by melt-spinning a polymer polymerized in the same manner as in Example 1 and cold-drawing the undrawn yarn at a draw ratio of 4.0 times are shown in Table 1. When the drawn yarn was knitted with nylon fiber and made into stockings,
Since the 100% elongation recovery rate is as low as 74%, the elastic properties are insufficient, and the dry heat shrinkage stress is 9.7 × 10
Due to the high ^-2 cN / dtex, the product had poor dimensional stability and a hard texture.

(Comparative Example 3) A polymer polymerized by the same method as in Example 1 was melt-spun, and the undrawn yarn wound was cold-drawn at a draw ratio of 4.0 and then contacted with a hot plate at 70 ° C. While relaxing, a relaxation heat treatment was performed at a relaxation rate of 30%. The physical properties of the obtained drawn-relaxed heat-treated yarn are also shown in Table 1. The obtained fiber had a low elongation recovery rate of 85% and poor elastic properties.

(Example 2) In the same manner as in Example 1,
26.3 parts by weight of caprolactam, 5.5 parts by weight of adipic acid, 75.2 parts by weight of poly (tetramethylene oxide) glycol having a number average molecular weight of 650, "Irganox 10
Polymerization was carried out by charging 0.5 parts by weight of 98 ″ (antioxidant). Relative viscosity (ηr) of the obtained polymer (measurement solvent: orthochlorophenol 0.5%, measurement temperature: 25 ° C.)
Was 2.11 and the melting point by DSC was 166 ° C.

This polymer was melt-spun at a spinning temperature of 220 ° C. and wound at 400 m / min to obtain an undrawn yarn of 44 dtex and 3 filaments. The resulting undrawn yarn was subjected to a relaxation heat treatment at a relaxation rate of 20% while being in contact with a hot plate at 70 ° C. Table 1 also shows the physical properties of the obtained relaxed heat-treated yarn. When the fibers were cross-knitted with nylon fibers to form a stocking, it was a product having an appropriate tightening feeling and good texture.

(Example 3) In the same manner as in Example 1, ε-
26.3 parts by weight of caprolactam, 5.5 parts by weight of adipic acid, 75.2 parts by weight of poly (tetramethylene oxide) glycol having a number average molecular weight of 3,800, "Irganox 1
098 ″ (antioxidant) was added and 0.5 parts by weight were polymerized. The relative viscosity (ηr) of the obtained polymer (measuring solvent: orthochlorophenol 0.5%, measuring temperature: 25)
C) was 2.28 and the melting point by DSC was 187 ° C.

The polymer was melt-spun at a spinning temperature of 220 ° C. and wound at 400 m / min to obtain a 50 dtex, 3-filament undrawn yarn. The obtained undrawn yarn was subjected to a relaxation heat treatment at a relaxation rate of 10% while being in contact with a hot plate at 70 ° C. Table 1 also shows the physical properties of the obtained relaxed heat-treated yarn. When the fiber was cross-knitted with a nylon fiber to form a stocking, it was found to be a product having an appropriate tightening feeling and a good texture, and also having excellent recoverability upon repeated use.

(Example 4) In the same manner as in Example 1,
18.1 parts by weight of caprolactam, 3.9 parts by weight of adipic acid, 80.3 parts by weight of poly (tetramethylene oxide) glycol having a number average molecular weight of 2000, "Irganox 1
098 ″ (antioxidant) was added and 0.5 parts by weight were polymerized. The relative viscosity (ηr) of the obtained polymer (measuring solvent: orthochlorophenol 0.5%, measuring temperature: 25)
C) was 2.20 and the melting point by DSC was 171 ° C.

This polymer was melt-spun at a spinning temperature of 220 ° C. and wound at 400 m / min to obtain an undrawn yarn of 44 dtex and 3 filaments. The resulting undrawn yarn was subjected to a relaxation heat treatment at a relaxation rate of 20% while being in contact with a hot plate at 70 ° C. Table 1 also shows the physical properties of the obtained relaxed heat-treated yarn. When the fiber was cross-knitted with a nylon fiber to form a stocking, it was found to be a product having an appropriate tightening feeling and a good texture, and also having excellent recoverability upon repeated use.

(Example 5) In the same manner as in Example 1,
26.3 parts by weight of caprolactam, 5.5 parts by weight of glutaric acid, 75.2 parts by weight of poly (tetramethylene oxide) glycol having a number average molecular weight of 2000, "Irganox 1
098 ″ (antioxidant) was added and 0.5 parts by weight were polymerized. The relative viscosity (ηr) of the obtained polymer (measuring solvent: orthochlorophenol 0.5%, measuring temperature: 25)
C) was 2.26 and the melting point by DSC was 173 ° C.

This polymer was melt-spun at a spinning temperature of 220 ° C. and wound at 400 m / min to obtain an undrawn yarn of 55 dtex and 3 filaments. A constant length heat treatment was performed while bringing the obtained undrawn yarn into contact with a hot plate at 70 ° C. Table 1 also shows the physical properties of the obtained constant-length heat-treated yarn. When the fiber was cross-knitted with a nylon fiber to form a stocking, it was found to be a product having an appropriate tightening feeling and a good texture, and also having excellent recoverability upon repeated use.

(Embodiment 6) In the same manner as in Embodiment 1, ε-
26.3 parts by weight of caprolactam, 7.5 parts by weight of sebacic acid, 75.2 parts by weight of poly (tetramethylene oxide) glycol having a number average molecular weight of 2000, "Irganox 1
098 ″ (antioxidant) was added and 0.5 parts by weight were polymerized. The relative viscosity (ηr) of the obtained polymer (measuring solvent: orthochlorophenol 0.5%, measuring temperature: 25)
° C) was 2.08, and the melting point by DSC was 179 ° C.

This polymer was melt-spun at a spinning temperature of 220 ° C. and wound at 400 m / min to obtain a 55 dtex, 3-filament undrawn yarn. A constant length heat treatment was performed while bringing the obtained undrawn yarn into contact with a hot plate at 70 ° C. Table 1 also shows the physical properties of the obtained constant-length heat-treated yarn. When the fibers were cross-knitted with nylon fibers to form a stocking, it was a product having an appropriate tightening feeling and good texture.

(Examples 7 and 8) In the same manner as in Example 1,
9.7 parts by weight of ε-caprolactam, 2.3 parts by weight of adipic acid, 85.3 parts by weight of poly (tetramethylene oxide) glycol having a number average molecular weight of 2000, 0.5 parts by weight of “Irganox 1098” (antioxidant) Was charged to perform polymerization. Relative viscosity (ηr) of the obtained polymer (measurement solvent orthochlorophenol 0.5%, measurement temperature 25
C) was 1.99, and the melting point by DSC was 168 ° C.

This polymer was melt-spun at a spinning temperature of 210 ° C. and wound at 400 m / min to obtain an undrawn yarn of 44 dtex and 3 filaments. The resulting undrawn yarn was subjected to a relaxation heat treatment at a relaxation rate of 30% while being in contact with a hot plate at 70 ° C. Table 1 also shows the physical properties of the obtained relaxed heat-treated yarn. When the fibers were cross-knitted with nylon fibers to form stockings, it was a product having a good texture (Example 7). On the other hand, a relaxation heat treatment was performed at a relaxation rate of 45% while the undrawn yarn was in contact with a hot plate at 70 ° C. Although the process stability was somewhat problematic, the stockings obtained by knitting the fibers with nylon fibers were products having a good texture (Example 8).

(Embodiment 9) In the same manner as in Embodiment 1, ε-
31.3 parts by weight of caprolactam, 10.5 parts by weight of adipic acid, 65.2 parts by weight of poly (tetramethylene oxide) glycol having a number average molecular weight of 2000, and 0.5 parts by weight of "Irganox 1098" (antioxidant). The polymerization was carried out. Relative viscosity (ηr) of the obtained polymer (measurement solvent orthochlorophenol 0.5%, measurement temperature 25
° C) was 2.06, and the melting point by DSC was 183 ° C.

This polymer was melt-spun at a spinning temperature of 220 ° C. and wound at 400 m / min to obtain an undrawn yarn of 50 dtex and 3 filaments. The obtained undrawn yarn was subjected to a relaxation heat treatment at a relaxation rate of 10% while being in contact with a hot plate at 70 ° C. Table 1 also shows the physical properties of the obtained relaxed heat-treated yarn. When the fiber was cross-knitted with a nylon fiber to form a stocking, it was found to be a product having an appropriate tightening feeling and a good texture, and also having excellent recoverability upon repeated use.

(Embodiment 10) In the same manner as in Embodiment 1, ε
36.3 parts by weight of caprolactam, 15.5 adipic acid
5 parts by weight of poly (tetramethylene oxide) glycol having a number average molecular weight of 2,000 and 0.5 parts by weight of "Irganox 1098" (antioxidant) were charged to perform polymerization. Relative viscosity (ηr) of the obtained polymer
(Measurement solvent: orthochlorophenol 0.5%, measurement temperature: 25 ° C.) was 1.93, and the melting point by DSC was 187 ° C.

This polymer was melt-spun at a spinning temperature of 230 ° C. and wound at 400 m / min to obtain an undrawn yarn of 55 dtex and 3 filaments. A constant length heat treatment was performed while bringing the obtained undrawn yarn into contact with a hot plate at 70 ° C. Table 1 also shows the physical properties of the obtained constant-length heat-treated yarn. When the fibers were cross-knitted with nylon fibers to form stockings, the products had a good texture.

Comparative Example 4 In the same manner as in Example 1, ε-
26.3 parts by weight of caprolactam, 5.5 parts by weight of adipic acid, 75.2 parts by weight of poly (tetramethylene oxide) glycol having a number average molecular weight of 400, "Irganox 10
Polymerization was carried out by charging 0.5 parts by weight of 98 ″ (antioxidant). Relative viscosity (ηr) of the obtained polymer (measurement solvent: orthochlorophenol 0.5%, measurement temperature: 25 ° C.)
Was 2.25, and the melting point by DSC was 161 ° C.

The polymer was melt-spun at a spinning temperature of 210 ° C. and wound at 400 m / min to obtain a 44 dtex, 3-filament undrawn yarn. The resulting undrawn yarn was subjected to a relaxation heat treatment at a relaxation rate of 20% while being in contact with a hot plate at 70 ° C. Table 1 also shows the physical properties of the obtained relaxed heat-treated yarn. When the fibers were cross-knitted with nylon fibers to form a stocking, the product had a tight tightening feeling.

Comparative Example 5 In the same manner as in Example 1, ε-
26.3 parts by weight of caprolactam, 5.5 parts by weight of adipic acid, 75.2 parts by weight of poly (tetramethylene oxide) glycol having a number average molecular weight of 4,500, "Irganox 1
Polymerization was carried out by charging 0.5 parts by weight of 098 ″ (antioxidant), but no satisfactory polymer was obtained due to severe phase separation.

(Comparative Example 6) As in Example 1, ε-
26.3 parts by weight of caprolactam, 5.5 parts by weight of oxalic acid, 75.2 parts by weight of poly (tetramethylene oxide) glycol having a number average molecular weight of 2000, "Irganox 1
098 ″ (antioxidant) was added and 0.5 parts by weight were polymerized. The relative viscosity (ηr) of the obtained polymer (measuring solvent: orthochlorophenol 0.5%, measuring temperature: 25)
C.) was 2.25 and the melting point by DSC was 171 ° C.

This polymer was melt-spun at a spinning temperature of 220 ° C. and wound at 400 m / min to obtain an undrawn yarn of 44 dtex and 3 filaments. The resulting undrawn yarn was subjected to a relaxation heat treatment at a relaxation rate of 20% while being in contact with a hot plate at 70 ° C. Table 1 also shows the physical properties of the obtained relaxed heat-treated yarn. The fiber had a low 100% elongation recovery rate of 87%, and had insufficient elastic properties.

(Comparative Example 7) As in Example 1, ε-
26.3 parts by weight of caprolactam, 5.5 parts by weight of dodecanedioic acid, 75.2 parts by weight of poly (tetramethylene oxide) glycol having a number average molecular weight of 2000, and 0.5 parts by weight of "Irganox 1098" (antioxidant) The polymerization was carried out. Relative viscosity (ηr) of the obtained polymer (measurement solvent orthochlorophenol 0.5%, measurement temperature 25
C) was 1.93, and the melting point by DSC was 182 ° C.

This polymer was melt spun at a spinning temperature of 220 ° C. and wound at 400 m / min to obtain an undrawn yarn of 44 dtex and 3 filaments. The resulting undrawn yarn was subjected to a relaxation heat treatment at a relaxation rate of 20% while being in contact with a hot plate at 70 ° C. Table 1 also shows the physical properties of the obtained relaxed heat-treated yarn. This fiber had a low 100% elongation recovery rate of 79%, and had insufficient elastic properties.

(Comparative Example 8) As in Example 1, ε-
6.3 parts by weight of caprolactam, 1.4 parts by weight of adipic acid, 97.2 parts by weight of poly (tetramethylene oxide) glycol having a number average molecular weight of 2000, "Irganox 1
098 ″ (antioxidant) was added and 0.5 parts by weight were polymerized. The relative viscosity (ηr) of the obtained polymer (measuring solvent: orthochlorophenol 0.5%, measuring temperature: 25)
° C) was 2.31 and the melting point by DSC was 161 ° C.

This polymer was melt spun at a spinning temperature of 200 ° C. and wound at 400 m / min to obtain a 39 dtex, 3-filament undrawn yarn. The resulting undrawn yarn was subjected to a relaxation heat treatment at a relaxation rate of 30% while being in contact with a hot plate at 70 ° C. Table 1 also shows the physical properties of the obtained relaxed heat-treated yarn. The fibers had a low 60% recovery stress and had insufficient elastic properties.

(Comparative Example 9) As in Example 1, ε-
53.8 parts by weight of caprolactam, 14.8 parts by weight of adipic acid, 42.3 parts by weight of poly (tetramethylene oxide) glycol having a number average molecular weight of 2000, and 0.5 parts by weight of "Irganox 1098" (antioxidant) The polymerization was carried out. Relative viscosity (ηr) of the obtained polymer (measurement solvent orthochlorophenol 0.5%, measurement temperature 25
C) was 1.89, and the melting point by DSC was 196 ° C.

This polymer was melt-spun at a spinning temperature of 240 ° C. and wound at 400 m / min to obtain an undrawn yarn of 55 dtex and 3 filaments. A constant length heat treatment was performed while bringing the obtained undrawn yarn into contact with a hot plate at 70 ° C. Table 1 also shows the physical properties of the obtained constant-length heat-treated yarn. The fiber is 10
The 0% elongation recovery rate was as low as 45%, and the elastic properties were insufficient.

Example 11 26.4 parts by weight of an aqueous solution of hexamethylenediamine (concentration: 66.3% by weight), 54.2 parts by weight of adipic acid, 83.7 parts by weight of poly (tetramethylene oxide) glycol having a number average molecular weight of 2,000 And 0.5 parts by weight of “Irganox 1098” (antioxidant), and reacted at 240 ° C. for 1 hour in a nitrogen atmosphere under normal pressure, then heated to 260 ° C. and polymerized at 1 mmHg or less for 3 hours. Was. Relative viscosity (ηr) of the obtained polymer (measurement solvent orthochlorophenol 0.5%, measurement temperature 25
C) was 1.94 and the melting point by DSC was 198 ° C.

This polymer was melt-spun at a spinning temperature of 220 ° C. and wound at 400 m / min to obtain an undrawn yarn of 44 dtex and 3 filaments. Relaxation heat treatment was performed at a relaxation rate of 20% while the undrawn yarn was in contact with a hot plate at 70 ° C.
Table 1 also shows the physical properties of the obtained relaxed heat-treated yarn. When the fiber was cross-knitted with a nylon fiber to form a stocking, it was found to be a product having an appropriate tightening feeling and a good texture, and also having excellent recoverability upon repeated use.

Example 12 ω-Aminododecanoic acid 2
3.6 parts by weight, 5.2 parts by weight of adipic acid, 71.2 parts by weight of poly (tetramethylene oxide) glycol having a number average molecular weight of 2000, and 0.5 part by weight of "Irganox 1098" (antioxidant), Under normal pressure in nitrogen atmosphere 23
After reacting at 0 ° C for 2 hours, the temperature was raised to 250 ° C and 1 mm
Polymerization was carried out at Hg or lower for 3 hours. The relative viscosity (ηr) of the obtained polymer (measuring solvent orthochlorophenol 0.5%, measuring temperature 25 ° C.) was 2.09, and the melting point by DSC was 138 ° C.

This polymer was melt-spun at a spinning temperature of 220 ° C. and wound at 400 m / min to obtain an undrawn yarn of 44 dtex and 3 filaments. Relaxation heat treatment was performed at a relaxation rate of 20% while the undrawn yarn was in contact with a hot plate at 70 ° C.
Table 1 also shows the physical properties of the obtained relaxed heat-treated yarn. When the fiber was cross-knitted with a nylon fiber to form a stocking, it was found to be a product having an appropriate tightening feeling and a good texture, and also having excellent recoverability upon repeated use.

[0065]

The polyamide elastic fiber of the present invention can be produced by melt spinning and has excellent elastic properties and dimensional stability when formed into a woven or knitted fabric. Further, according to the production method of the present invention, the undrawn yarn wound by the melt spinning method is subjected to a heat treatment in a relaxed or fixed length state,
An elastic fiber having significantly improved elastic properties can be obtained.

[Brief description of the drawings]

FIG. 1 is a diagram showing a hysteresis curve of an elastic fiber of the present invention.

Claims (7)

[Claims] 1. A polyamide having a hard segment derived from polyamide, a soft segment derived from poly (alkylene oxide) glycol and / or poly (alkylene oxide) diamine having a number average molecular weight of 500 to 4000, and having 4 carbon atoms.
A polyamide-based elastic fiber comprising a polyamide elastomer having a chain extended by a dicarboxylic acid of 10 to 10 and a weight ratio of a hard segment of 5 to 40%,
00% elongation recovery rate is 90% or more, dry heat shrinkage stress is 4 × 1
0 ^-2 cN / dtex or less, 60% recovery stress of 1 × 10 ^-2
~ 5 × 10 ^-2 cN / dtex, hysteresis loss is 60
% Or less. 2. The polyamide elastic fiber according to claim 1, wherein the polyamide is nylon 6. 3. The polyamide elastic fiber according to claim 1, wherein the polyamide is nylon 66. 4. The polyamide-based elastic fiber according to claim 1, wherein the polyamide is nylon 12. 5. A polyamide having a hard segment derived from polyamide, a soft segment derived from poly (alkylene oxide) glycol and / or poly (alkylene oxide) diamine having a number average molecular weight of 500 to 4000, and having 4 carbon atoms.
The unstretched yarn obtained by melt-spinning a polyamide elastomer obtained by chain elongation with a dicarboxylic acid of 10 to 10 and having a hard segment weight ratio of 5 to 40% is 40 ° C. or more, and 10 ° C. from the polymer melting point (Tm). A method for producing a polyamide-based elastic fiber, comprising heat-treating in a relaxed or fixed-length state at a low temperature or lower. 6. The method for producing a polyamide-based elastic fiber according to claim 5, wherein the relaxed state has a relaxation rate of 40% or less. 7. A woven or knitted fabric comprising at least a part of the polyamide-based elastic fiber according to claim 1.