Polyurethane elastic yarn and production method thereof

Abstract

[Problem] To provide a polyurethane elastic yarn which has the high strength and ductility sought in polyurethane elastic yarn, and also has excellent durability and heat resistance, as well as little fatigue at low temperature; and a production method thereof. [Means of Resolution] A polyurethane elastic yarn made from polyurethane which has polymer diol and diisocyanate as starting substances, wherein said polyurethane comprises a polyurethane A containing a polybutadiene structure in which the proportion of 1,2-bonded butadiene structure to 1,4-bonded butadiene structure in the molecule is in the range from 91:9 to 20:80.

Claims

1. A polyurethane elastic yarn made from polyurethane which has polymer diol and diisocyanate as starting substances, wherein said polymer diol comprises polytetramethylene ether glycol (PTMG) or modified PTMG, and said polyurethane comprises a blend of (i) polyurethane A containing a polybutadiene structure in which the proportion of 1,2-bonded butadiene structure to 1,4-bonded butadiene structure in the molecule is in the range from 70:30 to 40:60; and (ii) polyurethane B made from a polymer diol other than said polybutadiene diol or polyisoprenediol and diisocyanate, wherein said polyurethane elastic yarn exhibits increased chemical resistance as measured by strength as compared to polyurethane yarns outside the range from 70:30 to 40:60 of the polybutadiene structure.

2. The polyurethane elastic yarn according to claim 1, wherein said polyurethane A is polyurethane obtained by copolymerization of a polydiene diol selected from the group consisting of polybutadiene diol, polyisoprene diol, and mixtures thereof, a polymer diol other than said polydiene diol and diisocyanate.

3. A method of producing a polyurethane elastic yarn by spinning a spinning starting solution containing polyurethane having polymer diol and diisocyanate as starting substances, wherein said polymer diol comprises polytetramethylene ether glycol (PTMG) or modified PTMG, and said polyurethane comprises a blend of (i) polyurethane A containing a polybutadiene structure in which the proportion of 1,2-bonded butadiene structure to 1,4-bonded butadiene structure in the molecule is in the range from 70:30 to 40:60 and prepared from a polybutadiene dial and diisocyanate; and (ii) polyurethane B made from a polymer diol other than said polybutadiene diol or polyisoprenediol and diisocyanate, wherein said polyurethane elastic yarn exhibits increased chemical resistance as measured by strength as compared to polyurethane yarns outside the range from 70:30 to 40:60 of the polybutadiene structure.

4. The method of producing a polyurethane elastic yarn according to claim 3, wherein the spinning method is dry spinning.

5. A polyurethane elastic yarn made from polyurethane which has polymer diol and diisocyanate as starting substances, wherein said polymer diol comprises polytetramethylene ether glycol (PTMG) or modified PTMG, and said polyurethane comprises a blend of (i) polyurethane A containing a polybutadiene structure in which the proportion of 1,2-bonded butadiene structure to 1,4-bonded butadiene structure in the molecule is in the range from 70:30 to 40:60; and (ii) polyurethane B made from a polyether-based diol and a diisocyanate, wherein said polyurethane elastic yarn exhibits increased chemical resistance as measured by strength as compared to polyurethane yarns outside the range from 70:30 to 40:60 of the polybutadiene structure.

6. The polyurethane elastic yarn of claim 5, wherein said diisocyanate is selected from the group consisting of diphenylmethane diisocyanate, tolylene diisocyanate, 1,4 diisocyanate benzene, xylylene diisocyanates, 2,6-naphthalene diisocyanates, methylenebis(cyclohexyl isocyanate), isophorone diisocyanate, methylcyclohexane 2,4-diisocyanate, methylcyclohexane 2,6-diisocyanate, cyclohexane 1,4-diisocyanate, hexahydro xylylene diisocyanate, hexahydro tolylene diisocyanate and octahydro 1,5-naphthalene diisocyanate.

Description

EXAMPLES

(1) The present invention is explained in further detail by means of examples. First, the evaluation methods of the various characteristics in the present invention are explained.

(2) Analysis Method of Polymer Diol Having a Polybutadiene Structure in which the Proportion of 1,2-Bonded Butadiene Structure to 1,4-Bonded Butadiene Structure in the Yarn is in the Range from 91:9 to 20:80

(3) The polyurethane elastic yarn was measured by an IR meter. The contained amounts in the yarn were determined from absorption near 907 cm.sup.1, by a calibration curve using polyurethane containing a known concentration of polybutadiene diol.

(4) Permanent Set, Stress Relaxation, Fracture Strength, Fracture Ductility

(5) The permanent set, stress relaxation, fracture strength and fracture ductility of the polyurethane elastic yarn were measured using an Instron model 4502 tensile testing machine. The number of measurements was n=3, and the average of these was used. Stress relaxation, fracture strength and fracture ductility were measured at 22 C., while permanent set was measured at both 22 C. and 5 C.

(6) These are defined as follows.

(7) A sample 5 cm long (L1) was stretched 300% at a pulling speed of 50 cm/minute five times repeatedly, and the stress when stretched 300% for the fifth time was taken as G1. Then, the length of the sample was held for 30 seconds in the 300% stretched state. The stress after being held for 30 seconds was taken as G2. Then, the length of the sample when the sample length was allowed to recover and stress returned to 0 was taken as L2. In addition, the sixth time, the sample was stretched until fracture. The stress at fracture was taken as G3, and the sample length at fracture was taken as L3. The aforementioned characteristics are calculated by the equations below.

(8) Fracture strength (cN)=G3

(9) Stress relaxation (%)=100(G1G2)/G1

(10) Permanent set (%)=100(L2L1)/L1

(11) Fracture ductility (%)=100(L3L1)/L1

(12) Chemical Resistance

(13) The yarn was affixed in the 100% stretched state, and the following three exposure treatments were performed. First, the yarn was immersed for 1 hour in a hexane solution of oleic acid (5 wt %), then it was immersed for 2 hours in hypochlorous acid solution (chlorine concentration 500 ppm), and then it was exposed to UV for 2 hours. The UV exposure treatment was performed at 63 C., 60% relative humidity using a carbon arc fadometer made by Suga Test Instruments Co., Ltd. After this exposure treatment was performed a total of two times, the yarn was left free for 24 hours at room temperature, and fracture strength (G4) was measured by the same method as above. The proportion of fracture strength after treatment (G4) with respect to fracture strength of the untreated yarn (G3) was taken as the chemical resistance. The number of measurements was n=3, and the average of these was used.

(14) Chemical resistance (%)=100G4/G3

(15) Alkali Resistance

(16) Treatment which is expected in a weight reduction process of polyester fiber was performed, and the fracture strength retention rate of the yarn was evaluated as an index of the alkali resistance of the polyurethane yarn.

(17) The yarn was affixed in the 100% stretched state, and it was sealed in a pressure vessel, which was then filled with an aqueous solution containing 8.0 wt % each of a cation-based weight reduction promoter (DXN-10 made by Ipposha) and sodium hydroxide. After being treated for 120 minutes at 100 C., the yarn was left free for 24 hours at room temperature, and fracture strength (G5) was measured by the same method as above. The proportion of fracture strength after treatment (G5) with respect to fracture strength of the untreated yarn (G3) was taken as the alkali resistance. The number of measurements was n=3, and the average of these was used.

(18) Alkali resistance (%)=100G5/G3

(19) Heat Softening Point

(20) Heat softening point was measured as an index of heat resistance of the polyurethane yarn. The temperature distribution of dynamic storage modulus E of the polyurethane yarn was measured at a heating rate of 10 C./minute, using a dynamic storage modulus measurement machine model RSA II made by Rheometrics. The heat softening point was determined from the intersection between the tangent of the E curve in the region between 80 C. and 130 C. and the tangent of the E curve produced when E was reduced by softening at 160 C. and above. Furthermore, E was on a logarithmic axis, and temperature was on a linear axis. The number of measurements was n=3, and the average of these was used.

(21) Melting Point

(22) High-temperature melting pointthat is, the melting point of the hard segment crystalswas measured as an index of heat resistance of the polyurethane yarn. The irreversible heat flow of the polyurethane yarn was measured at a heating rate of 3 C./minute using a model 2920 modulated DSC made by TA Instruments, and its peak was taken as the melting point. The number of measurements was n=3, and the average of these was used.

(23) Quality of Appearance of Dyed Stretch Fabric

(24) Dyed stretch fabric was left still on a flat work surface so that wrinkles could be seen. It was observed visually, and evaluated at the following three levels.

(25) O: No slackening, crimping or broken yarns, and no problems at all in actual use

(26) : Usable, but there is partial slackening

(27) x: There are slackening, crimping and broken yarns, and it is unusable

Example 1

(28) A DMAc solution of 35 wt % polyurethane polymer (a1) made from PTMG of molecular weight 2900, MDI and ethylene glycol was polymerized by ordinary methods, thereby making polymer solution A1. Then, for a polyurethane containing a polybutadiene structure in which the proportion of 1,2-bonded butadiene structure to 1,4-bonded butadiene structure was 65:35, a DMAc solution of 35 wt % polyurethane polymer (b1) made from LBH 2000 made by Idemitsu Kosan Co., Ltd. having the structure shown in compound 1, MDI and ethylene glycol was polymerized, thereby making polymer solution B1. As an antioxidant, a polyurethane solution produced by the reaction of t-butyldiethanolamine and methylene-bis(4-cyclohexylisocyanate) (Methacrol 2462 made by DuPont (c1)) and a condensation polymer of p-cresol and divinylbenzene (Methacrol 2390 made by DuPont (c2)) were mixed in a weight ratio of 2 to 1, and a DMAc solution of the antioxidant (concentration 35 wt %) was prepared, and this was used as other additive solution C1 (35 wt %).

(29) Then, 92 wt % of the polymer solution A1, 5 wt % of the polymer solution B1 and 3 wt % of the other additive solution C1 were uniformly mixed, thereby making spinning solution D1. This spinning solution was dry-spun and wound at a spinning speed of 540 m/minute and a speed ratio of the godet roller and winder of 1.4, thereby producing 20 dtex/monofilament polyurethane elastic yarn (200 g spool).

(30) The composition (wt %) of the obtained polyurethane elastic yarn was as shown in Table 1.

(31) The fracture ductility, fracture strength, permanent strain rate, stress relaxation, chemical resistance, alkali resistance, heat softening point and melting point of this polyurethane elastic yarn are shown in Table 2. Fracture ductility and strength were both greater than those in comparative example 1 (described below). Relaxation stress and permanent strain rate at 22 C. were lower than in comparative example 1, and permanent strain rate at 5 C. was reduced to about of that in comparative example 1, indicating that recoverability improved. Chemical resistance and alkali resistance were at least twice those in comparative example 1. Heat softening point and melting point, which are indices of heat resistance, both improved over comparative example 1.

(32) Additionally, a stretch weave was created by the following method, and the quality of its appearance was evaluated.

(33) First, a covering process was performed on the obtained polyurethane elastic yarn. Using regular 168 dtex/48-filament polyester fiber as the covering yarn, it was processed with 450 twists per meter and a draft of 3.0 using a covering machine, thereby making a covering yarn for the woof yarn. Similarly, using regular 168 dtex/48-filament polyester fiber as the covering yarn, it was processed with 700 twists per meter and a draft of 3.5 using a covering machine, thereby making a covering yarn for the warp yarn.

(34) Next, warping and weaving were performed. To do this, 5100 warp yarns (rough winding warp 1100 yarns) were starched and warped, and they were woven with a 2/1 twill form using a rapier weaver.

(35) After that, a dying process was performed. The product obtained by weaving was put through the following processes by ordinary methods, in this order: scouring, intermediate setting (185 C.), alkali weigh reduction (N treatment), embossing (190 C.), dying (130 C.), drying, finishing agent treatment and finishing setting (180 C., fabric speed 20 m/minute, set zone 24 m).

(36) The obtained stretch weave had an excellent quality of appearance without flaws.

Example 2

(37) For a polyurethane containing a polybutadiene structure in which the proportion of 1,2-bonded butadiene structure to 1,4-bonded butadiene structure was 65:35, a DMAc solution of 35 wt % polyurethane urea polymer (b2) made from LBH 3000 made by Idemitsu Kosan Co., Ltd., MDI and ethylenediamine was polymerized by ordinary methods, thereby making polymer solution B2. Then, 77 wt % of the polymer solution A1 prepared in example 1, 20 wt % of the polymer solution B2 prepared here and 3 wt % of the other additive solution C1 prepared in example 1 were uniformly mixed, thereby making spinning solution D2.

(38) This spinning solution D2 was dry-spun and wound at a spinning speed of 540 m/minute and a speed ratio of the godet roller and winder of 1.40, thereby producing 20 dtex/monofilament polyurethane elastic yarn (200 g spool).

(39) The composition (wt %) of the obtained polyurethane elastic yarn was as shown in Table 1.

(40) The fracture ductility, fracture strength, permanent strain rate, stress relaxation, chemical resistance, alkali resistance, heat softening point and melting point of this polyurethane elastic yarn are shown in Table 2. Fracture ductility and breaking fracture strength were both greater than those in comparative example 1 (described below). Relaxation stress and permanent strain rate at 22 C. were lower than in comparative example 1, and permanent strain rate at 5 C. was reduced to less than of that in comparative example 1, indicating that recoverability improved. Chemical resistance and alkali resistance were at least twice those in comparative example 1. Heat softening point and melting point, which are indices of heat resistance, both improved over comparative example 1.

(41) Also, a stretch weave was produced by the same method as in example 1, and when quality of appearance was evaluated, the obtained stretch weave had an excellent quality of appearance without flaws.

Example 3

(42) A DMAc solution of 35 wt % polyurethane urea polymer (a2) made from PTMG of molecular weight 1800, MDI, ethylenediamine and diethylamine as a terminal blocking agent was polymerized by ordinary methods, thereby making polymer solution A2. Then, 87 wt % of this polymer solution A2, 10 wt % of the polymer solution B2 prepared in example 2 and 3 wt % of the other additive solution C1 prepared in example 1 were uniformly mixed, thereby making spinning solution D3.

(43) This spinning solution D3 was dry-spun and wound at a spinning speed of 600 m/minute and a speed ratio of the godet roller and winder of 1.20, thereby producing 20 dtex/2-filament multifilament polyurethane elastic yarn (500 g spool).

(44) The composition (wt %) of the obtained polyurethane elastic yarn was as shown in Table 1.

(45) The fracture ductility, fracture strength, permanent set, stress relaxation, chemical resistance, alkali resistance, heat softening point and melting point of this polyurethane elastic yarn are shown in Table 2. Fracture ductility and fracture strength were both greater than those in comparative example 2 (described below). Relaxation stress and permanent set at 22 C. were lower than in comparative example 2, and permanent strain rate at 5 C. was reduced to less than of that in comparative example 1, indicating that recoverability improved. Chemical resistance and alkali resistance were 2 times and 3 times, respectively, those in comparative example 2. Heat softening point and melting point, which are indices of heat resistance, both improved over comparative example 2.

(46) Also, a stretch weave was produced by the same method as in example 1, and when quality of appearance was evaluated, the obtained stretch weave had an excellent quality of appearance without flaws.

Example 4

(47) 67 wt % of the polymer solution A2 prepared in example 3, 30 wt % of the polymer solution B1 prepared in example 1 and 3 wt % of the other additive solution C1 prepared in example 1 were uniformly mixed, thereby making spinning solution D4.

(48) This spinning solution D4 was dry-spun and wound at a spinning speed of 600 m/minute and a speed ratio of the godet roller and winder of 1.30, thereby producing 20 dtex/2-filament multifilament polyurethane elastic yarn (500 g spool).

(49) The composition (wt %) of the obtained polyurethane elastic yarn was as shown in Table 1.

(50) The fracture ductility, fracture strength, permanent set, stress relaxation, heat softening point, melting point and chemical resistance of this polyurethane elastic yarn are shown in Table 2. Fracture ductility and fracture strength were both greater than those in comparative example 2 (described below). Relaxation stress and permanent set at 22 C. were lower than in comparative example 2, and permanent set at 5 C. was reduced to less than of that in comparative example 2, indicating that recoverability improved. Chemical resistance and alkali resistance were 2.5 or more times and 3 times, respectively, those in comparative example 2. Heat softening point and melting point, which are indices of heat resistance, both improved over comparative example 2.

(51) Also, a stretch weave was produced by the same method as in example 1, and when quality of appearance was evaluated, the obtained stretch weave had an excellent quality of appearance without flaws.

Example 5

(52) 97 wt % of the polymer solution B1 prepared in example 1 and 3 wt % of the other additive solution C1 prepared in example 1 were uniformly mixed, thereby making spinning solution D5.

(53) This spinning solution D5 was dry-spun and wound at a spinning speed of 540 m/minute and a speed ratio of the godet roller and winder of 1.40, thereby producing 20 dtex/monofilament polyurethane elastic yarn (200 g spool).

(54) The composition (wt %) of the obtained polyurethane elastic yarn was as shown in Table 1.

(55) The fracture ductility, fracture strength, permanent set, stress relaxation, chemical resistance, alkali resistance, heat softening point and melting point of this polyurethane elastic yarn are shown in Table 2. Fracture ductility and fracture strength were both greater than those in comparative example 1 (described below). Relaxation stress and permanent set at 22 C. were lower than in comparative example 1, and permanent set at 5 C. was reduced to less than of that in comparative example 1, indicating that recoverability improved. Chemical resistance and alkali resistance were 2 or more times and 2.5 or more times, respectively, those in comparative example 1. Heat softening point and melting point, which are indices of heat resistance, both improved over comparative example 1.

(56) Also, a stretch weave was produced by the same method as in example 1, and when quality of appearance was evaluated, the obtained stretch weave had an excellent quality of appearance without flaws.

Example 6

(57) 97 wt % of the polymer solution B2 prepared in example 2 and 3 wt % of the other additive solution C1 prepared in example 1 were uniformly mixed, thereby making spinning solution D6.

(58) This spinning solution D6 was dry-spun and wound at a spinning speed of 600 m/minute and a speed ratio of the godet roller and winder of 1.30, thereby producing 20 dtex/2-filament multifilament polyurethane elastic yarn (500 g spool).

(59) The composition (wt %) of the obtained polyurethane elastic yarn was as shown in Table 1.

(60) The fracture ductility, fracture strength, permanent set, stress relaxation, heat softening point, melting point and chemical resistance of this polyurethane elastic yarn are shown in Table 2. Fracture ductility and fracture strength were both greater than those in comparative example 2 (described below). Relaxation stress and permanent set at 22 C. were lower than in comparative example 2, and permanent set at 5 C. was reduced to less than of that in comparative example 2, indicating that recoverability improved. Chemical resistance and alkali resistance were 2.5 or more times and 3 or more times, respectively, those in comparative example 2. Heat softening point and melting point, which are indices of heat resistance, both improved over comparative example 2.

(61) Also, a stretch weave was produced by the same method as in example 1, and when quality of appearance was evaluated, the obtained stretch weave had an excellent quality of appearance without flaws.

Example 7

(62) For a polyurethane containing a polybutadiene structure in which the proportion of 1,2-bonded butadiene structure to 1,4-bonded butadiene structure was 90:10, a DMAc solution of 35 wt % polyurethane polymer (b3) made from G-2000 made by Nippon Soda Co., Ltd. having the structure shown in compound 1, MDI and ethylene glycol was polymerized by ordinary methods, thereby making polymer solution B3. Then, 92 wt % of the polymer solution A1 prepared in example 1, 5 wt % of the polymer solution B3 prepared here and 3 wt % of the other additive solution C1 prepared in example 1 were uniformly mixed, thereby making spinning solution D7.

(63) This spinning solution D7 was dry-spun and wound at a spinning speed of 600 m/minute and a speed ratio of the godet roller and winder of 1.30, thereby producing 20 dtex/2-filament multifilament polyurethane elastic yarn (500 g spool).

(64) The composition (wt %) of the obtained polyurethane elastic yarn was as shown in Table 1.

(65) The fracture ductility, fracture strength, permanent set, stress relaxation, heat softening point, melting point and chemical resistance of this polyurethane elastic yarn are shown in Table 2. Fracture ductility and fracture strength were both greater than those in comparative example 1 (described below). Relaxation stress and permanent set at 22 C. were lower than in comparative example 1, and permanent set at 5 C. was reduced to less than of that in comparative example 1, indicating that recoverability improved. Chemical resistance and alkali resistance were each 1.5 or more times those in comparative example 1. Heat softening point, which is an index of heat resistance, was the same as in comparative example 1, and melting point improved over comparative example 1.

(66) Also, a stretch weave was produced by the same method as in example 1, and when quality of appearance was evaluated, the obtained stretch weave had an excellent quality of appearance without flaws.

Example 8

(67) For a polyurethane containing a polybutadiene structure in which the proportion of 1,2-bonded butadiene structure to 1,4-bonded butadiene structure was 20:80, a DMAc solution of 35 wt % polyurethane urea polymer (b4) made from R-45HT made by Idemitsu Kosan Co., Ltd. having the structure shown in compound 1, MDI and ethylenediamine was polymerized by ordinary methods, thereby making polymer solution B4. Then, 87 wt % of the polymer solution A2 prepared in example 3, 10 wt % of the polymer solution B4 prepared here and 3 wt % of the other additive solution C1 prepared in example 1 were uniformly mixed, thereby making spinning solution D8.

(68) This spinning solution D8 was dry-spun and wound at a spinning speed of 600 m/minute and a speed ratio of the godet roller and winder of 1.30, thereby producing 20 dtex/2-filament multifilament polyurethane elastic yarn (500 g spool).

(69) The composition (wt %) of the obtained polyurethane elastic yarn was as shown in Table 1.

(70) The fracture ductility, fracture strength, permanent set, stress relaxation, heat softening point, melting point and chemical resistance of this polyurethane elastic yarn are shown in Table 2. Fracture ductility and fracture strength were both greater than those in comparative example 2 (described below). Relaxation stress and permanent set at 22 C. were lower than in comparative example 2, and permanent set at 5 C. was reduced to less than of that in comparative example 2, indicating that recoverability improved. Chemical resistance and alkali resistance were each 2 or more times those in comparative example 2. Heat softening point and melting point, which are indices of heat resistance, both improved over comparative example 2.

(71) Also, a stretch weave was produced by the same method as in example 1, and when quality of appearance was evaluated, the obtained stretch weave had an excellent quality of appearance without flaws.

Example 9

(72) For a polyurethane containing a polybutadiene structure in which the proportion of 1,2-bonded butadiene structure to 1,4-bonded butadiene structure was 65:35, PTMG of molecular weight 1800 and LBH 3000 made by Idemitsu Kosan Co. were mixed in a mole ratio of 1:1, and this was used as polymer diol B. Then, a DMAc solution of 35 wt % of polyurethane polymer (b5) made from polymer diol B, MDI and ethylene diglycol was polymerized by ordinary methods, thereby making polymer solution B5. Then, 97 wt % of this polymer solution B5 and 3 wt % of the other additive solution C1 prepared in example 1 were uniformly mixed, thereby making spinning solution D9.

(73) This spinning solution D9 was dry-spun and wound at a spinning speed of 600 m/minute and a speed ratio of the godet roller and winder of 1.20, thereby producing 20 dtex/2-filament multifilament polyurethane elastic yarn (500 g spool).

(74) The composition (wt %) of the obtained polyurethane elastic yarn was as shown in Table 1.

(75) The fracture ductility, fracture strength, permanent set, stress relaxation, chemical resistance, alkali resistance, heat softening point and melting point of this polyurethane elastic yarn are shown in Table 2. Fracture ductility and fracture strength were both greater than those in comparative example 1 (described below). Relaxation stress and permanent set at 22 C. were lower than in comparative example 1, and permanent set at 5 C. was reduced to less than of that in comparative example 1, indicating that recoverability improved. Chemical resistance and alkali resistance were each 2 or more times those in comparative example 1. Heat softening point and melting point, which are indices of heat resistance, both improved over comparative example 1.

(76) Also, a stretch weave was produced by the same method as in example 1, and when quality of appearance was evaluated, the obtained stretch weave had an excellent quality of appearance without flaws.

Example 10

(77) For a polyurethane containing a polybutadiene structure in which the proportion of 1,2-bonded butadiene structure to 1,4-bonded butadiene structure was 65:35, a DMAc solution of 35 wt % of polyurethane urea polymer (b6) made from the polymer diol B stated in example 9, MDI, ethylenediamine and diethylamine as a terminal blocking agent was polymerized by ordinary methods, thereby making polymer solution B6. Then, 97 wt % of this polymer solution B6 and 3 wt % of the other additive solution C1 prepared in example 1 were uniformly mixed, thereby making spinning solution D10.

(78) This spinning solution D10 was dry-spun and wound at a spinning speed of 600 m/minute and a speed ratio of the godet roller and winder of 1.20, thereby producing 20 dtex/2-filament multifilament polyurethane elastic yarn (500 g spool).

(79) The composition (wt %) of the obtained polyurethane elastic yarn was as shown in Table 1.

(80) The fracture ductility, fracture strength, permanent set, stress relaxation, chemical resistance, alkali resistance, heat softening point and melting point of this polyurethane elastic yarn are shown in Table 2. Fracture ductility and fracture strength were both greater than those in comparative example 2 (described below). Relaxation stress and permanent set at 22 C. were lower than in comparative example 2, and permanent set at 5 C. was reduced to less than of that in comparative example 2, indicating that recoverability improved. Chemical resistance and alkali resistance were 2 or more times and 3 or more times, respectively, those in comparative example 2. Heat softening point and melting point, which are indices of heat resistance, both improved over comparative example 2.

(81) Also, a stretch weave was produced by the same method as in example 1, and when quality of appearance was evaluated, the obtained stretch weave had an excellent quality of appearance without flaws.

Comparative Example 1

(82) 97 wt % of the polymer solution A1 prepared in example 1 and 3 wt % of the other additive solution C1 prepared in example 1 were uniformly mixed, thereby making spinning solution E1. This spinning solution E1 was dry-spun and wound at a spinning speed of 540 m/minute and a speed ratio of the godet roller and winder of 1.40, thereby producing 20 dtex/monofilament polyurethane elastic yarn.

(83) The composition (wt %) of the obtained polyurethane elastic yarn was as shown in Table 1.

(84) The fracture ductility, fracture strength, permanent set, stress relaxation, chemical resistance, alkali resistance, heat softening point and melting point of this polyurethane elastic yarn are shown in Table 2. Chemical resistance and alkali resistance were both worse than in examples 1 and 2. Also, a stretch weave was produced by the same method as in example 1, and when quality of appearance was evaluated, the occurrence of partial billowing caused by fatigue of the polyurethane yarn due to its various processing history was seen in 15 places per 20 m.

Comparative Example 2

(85) 97 wt % of the polymer solution A2 prepared in example 3 and 3 wt % of the other additive solution C1 prepared in example 1 were uniformly mixed, thereby making spinning solution E2.

(86) This spinning solution E2 was dry-spun and wound at a spinning speed of 600 m/minute and a speed ratio of the godet roller and winder of 1.20, thereby producing 20 dtex/2-filament multifilament polyurethane elastic yarn (500 g spool).

(87) The composition (wt %) of the obtained polyurethane elastic yarn was as shown in Table 1.

(88) The fracture ductility, fracture strength, permanent set, stress relaxation, chemical resistance, alkali resistance, heat softening point and melting point of this polyurethane elastic yarn are shown in Table 2. Chemical resistance and alkali resistance were both worse than in examples 3 and 4. Also, a stretch weave was produced by the same method as in example 1, and when quality of appearance was evaluated, the occurrence of partial billowing caused by fatigue of the polyurethane yarn due to its various processing history was seen in 4 places per 20 m.

Comparative Example 3

(89) For a polyurethane containing a polybutadiene structure in which the proportion of 1,2-bonded butadiene structure to 1,4-bonded butadiene structure was 92.4:7.6, a DMAc solution of 35 wt % of polyurethane polymer (f1) made from PBD (made by Nippon Soda Co., Ltd.) stated in patent document 1 having the structure shown in compound 1, MDI and ethylene glycol was polymerized by ordinary methods, thereby making polymer solution F1. Then, 92 wt % of the polymer solution A1 prepared in example 1, 5 wt % of the polymer solution F1 prepared here and 3 wt % of the other additive solution C1 prepared in example 1 were uniformly mixed, thereby making spinning solution E3.

(90) This spinning solution E3 was dry-spun and wound at a spinning speed of 600 m/minute and a speed ratio of the godet roller and winder of 1.30, thereby producing 20 dtex/2-filament multifilament polyurethane elastic yarn (500 g spool).

(91) The composition (wt %) of the obtained polyurethane elastic yarn was as shown in Table 1.

(92) The fracture ductility, fracture strength, permanent set, stress relaxation, heat softening point, melting point and chemical resistance of this polyurethane elastic yarn are shown in Table 2. Permanent strain rate at 5 C. was lower than in comparative example 1, and chemical resistance and alkali resistance were greater than in comparative example 1, but they were worse than in examples 1, 5, 7 and the like. Also, a stretch weave was produced by the same method as in example 1, and when quality of appearance was evaluated, billowing due to fatigue, which was thought to be due to an increased permanent set of the polyurethane yarn, was seen all over, and the product was unsatisfactory.

Comparative Example 4

(93) For a polyurethane containing a polybutadiene structure in which the proportion of 1,2-bonded butadiene structure to 1,4-bonded butadiene structure was 92.4:7.6, a DMAc solution of 35 wt % of polyurethane urea polymer (f2) made from PBD (made by Nippon Soda Co., Ltd.) stated in patent document 1, MDI and ethylenediamine was polymerized by ordinary methods, thereby making polymer solution F2. Then, 87 wt % of the polymer solution A1 prepared in example 1, 10 wt % of the polymer solution F2 prepared here and 3 wt % of the other additive solution C1 prepared in example 1 were uniformly mixed, thereby making spinning solution E4.

(94) This spinning solution E4 was dry-spun and wound at a spinning speed of 600 m/minute and a speed ratio of the godet roller and winder of 1.30, thereby producing 20 dtex/2-filament multifilament polyurethane elastic yarn (500 g spool).

(95) The composition (wt %) of the obtained polyurethane elastic yarn was as shown in Table 1.

(96) The fracture ductility, fracture strength, permanent set, stress relaxation, heat softening point, melting point and chemical resistance of this polyurethane elastic yarn are shown in Table 2. Permanent strain rate at 5 C. was lower than in comparative example 2, and chemical resistance and alkali resistance were greater than in comparative example 2, but they were worse than in examples 3, 6, 8 and the like. Also, a stretch weave was produced by the same method as in example 1, and when quality of appearance was evaluated, billowing due to fatigue, which was thought to be due to an increased permanent set of the polyurethane yarn, was seen all over, and the product was unsatisfactory.

Comparative Example 5

(97) 97 wt % of the polymer solution F1 prepared in comparative example 3 and 3 wt % of the other additive solution C1 prepared in example 1 were uniformly mixed, thereby making spinning solution E5.

(98) It was attempted to dry-spin this spinning solution E5 at a spinning speed of 450 m/minute and a speed ratio of the godet roller and winder of 1.20, but it did not result in a yarn-like form, and a polyurethane elastic yarn was not obtained.

Comparative Example 6

(99) 97 wt % of the polymer solution F2 prepared in comparative example 4 and 3 wt % of the other additive solution C1 prepared in example 1 were uniformly mixed, thereby making spinning solution E6.

(100) It was attempted to dry-spin this spinning solution E6 at a spinning speed of 450 m/minute and a speed ratio of the godet roller and winder of 1.20, but it did not result in a yarn-like form, and a polyurethane elastic yarn was not obtained.

(101) Furthermore, the compositions (wt %) of the polyurethane elastic yarns obtained in the above examples 1-8 and comparative examples 1-4 as well as the compositions (wt %) of the polyurethanes prepared in comparative examples 5 and 6 are compiled in Table 1. Also, the fracture ductility, fracture strength, permanent set, stress relaxation, chemical resistance, alkali resistance, heat softening point and melting point of each of the polyurethane elastic yarns obtained in the above examples 1-8 and comparative examples 1-4 are compiled in Table 2.

(102) TABLE-US-00001 TABLE 1 Polyurethane containing polybutadiene structure b1 b2 b3 b4 b5 Polyurethane not Proportion of 1,2- Proportion of 1,2- Proportion of 1,2- Proportion of 1,2- containing polybutadiene bonded type to 1,4- bonded type to 1,4- bonded type to 1,4- bonded type to 1,4- structure bonded type bonded type bonded type bonded type a1 a2 65:35 90:10 20:80 65:35 Polyurethane Polyurethane Polyurethane Polyurethane Polyurethane Polyurethane Polyurethane polymer urea polymer polymer urea polymer polymer urea polymer polymer Example 1 92 5 Example 2 77 20 Example 3 87 10 Example 4 87 30 Example 5 97 Example 6 97 Example 7 92 5 Example 8 87 10 Example 9 97 Example 10 Comp. ex. 1 97 Comp. ex. 2 97 Comp. ex. 3 92 Comp. ex. 4 87 Comp. ex. 5 Comp. ex. 6 Polyurethane containing polybutadiene structure b6 f1 f2 Other additives Proportion of 1,2- Proportion of 1,2- c1 bonded type to 1,4- bonded type to 1,4- Polyurethane produced by c2 bonded type bonded type reaction of t-butyl- Condensation 65:35 92.4:7.6 diethanol-amine and polymer of Was dry Polyurethane Polyurethane Polyurethane methylene-bis(4-cyclohexyl- p-cresol and spinning urea polymer polymer urea polymer isocyanate) divinyl-benzene possible? Example 1 2 1 Yes Example 2 2 1 Yes Example 3 2 1 Yes Example 4 2 1 Yes Example 5 2 1 Yes Example 6 2 1 Yes Example 7 2 1 Yes Example 8 2 1 Yes Example 9 2 1 Yes Example 10 97 2 1 Yes Comp. ex. 1 2 1 Yes Comp. ex. 2 2 1 Yes Comp. ex. 3 5 2 1 Yes Comp. ex. 4 10 2 1 Yes Comp. ex. 5 97 2 1 No Comp. ex. 6 97 2 1 No

(103) TABLE-US-00002 TABLE 2 Heat Breaking Breaking Permanent set Stress Chemical Alkali softening elongation strength (%) relaxation resistance resistance point Melting point Quality of appearance (%) (cN) 22 C. 5 C. (%) (%) (%) ( C.) ( C.) of dyed stretch fabric example1 425 23 22 24 34 71 75 181 229 X example2 416 25 18 19 34 80 91 190 231 X example3 513 43 17 22 26 75 90 215 268 X example4 514 39 14 22 27 85 90 210 278 X example5 410 23 22 22 33 87 92 185 234 X example6 505 40 15 15 26 88 95 212 265 X example7 420 23 23 40 34 55 61 180 229 X example8 510 38 17 38 26 69 68 213 268 X example9 414 23 22 22 34 75 90 184 230 X example10 510 40 17 21 26 81 91 215 268 X comp. ex. 1 400 21 25 96 35 35 35 180 225 Y comp. ex. 2 460 25 20 90 28 29 30 205 265 Y comp. ex. 3 420 23 26 78 34 45 42 181 228 Z comp. ex. 4 510 38 19 74 26 55 44 210 267 Z

INDUSTRIAL USABILITY

(104) The polyurethane elastic yarn of the current invention has high strength and ductility, high durability, high heat resistance and good low-temperature characteristics. Therefore, clothing and the like that uses this elastic yarn has excellent desorption characteristics, fit, feel, ability to be dyed, fade resistance and quality of appearance, and the environment in which it is used is not limited.

(105) Also, because the polyurethane elastic yarn according to the present invention has these excellent characteristics, it can be used alone or in combination with various fibers to obtain an excellent stretch fabric, and it is suitable for knitting, weaving and braiding. Specific applications in which it can be used include various textile products such as socks, stockings, circular knits, tricot, swimwear, ski pants, work clothes, golf pants, wet suits, brassieres, girdles and gloves, elastic materials, waterproof elastic materials of sanitary products such as paper diapers, elastic materials for waterproof materials, imitation food, artificial flowers, electrical insulation materials, wiping cloth, copy cleaners, gaskets and the like.