CN119053734A - Thermoplastic polyurethane elastic fiber - Google Patents

Abstract

The problem to be solved by the present invention is to provide a thermoplastic polyurethane elastic fiber having excellent resistance to yellowing of NOx gas and heat resistance. The present invention relates to a thermoplastic polyurethane elastic fiber, characterized in that it contains at least one metal compound selected from the group consisting of metal hydroxides, metal carbonates and metal oxides in an amount of 0.05wt% to 5.00wt%, and the metal compound contains an alkali metal or an alkaline earth metal.

Description

Thermoplastic polyurethane elastic fiber

Technical Field

The present invention relates to thermoplastic polyurethane elastic fibers.

Background

Generally, polyurethane elastic fibers are used for clothing and sanitary materials. Polyurethane elastic fibers used in clothing and sanitary materials are required to have yellowing resistance and heat resistance.

Patent document 1 below discloses that a polyurethane elastic fiber obtained by dry spinning containing a hindered amine compound can improve yellowing resistance against NOx gas.

Patent document 2 discloses that the yellowing resistance of polyurethane resins against NOx gas can be improved by using a combination of a phenolic antioxidant, a hindered amine light stabilizer, a polyester compound, and a benzotriazole light stabilizer.

Patent document 3 discloses that heat resistance of polyurethane elastic fibers can be improved by melt-spinning a thermoplastic polyurethane resin obtained by reacting a two-terminal isocyanate-based prepolymer obtained by reacting a polyol with a diisocyanate and a two-terminal hydroxyl-based prepolymer obtained by reacting a polyol with a diisocyanate with a low-molecular-weight diol.

Patent document 4 discloses that the heat resistance of polyurethane elastic fiber can be improved by using an oil agent made of polydimethylsiloxane in combination with a phenolic antioxidant.

Prior art literature

Patent literature

Patent document 1 Japanese patent laid-open No. 2006-342448

Patent document 2 Japanese patent application laid-open No. 2009-19062

Patent document 3 Japanese patent laid-open No. 2006-307409

Patent document 4 Japanese patent laid-open publication No. 2003-20521

Disclosure of Invention

Problems to be solved by the invention

However, thermoplastic polyurethane elastic fibers having resistance to yellowing by NOx gas and heat resistance are not disclosed in references 1 to 4.

In view of the foregoing problems of the prior art, the present invention has been made to solve the problems of providing thermoplastic polyurethane elastic fibers having excellent resistance to yellowing by NOx gas and heat resistance.

Solution for solving the problem

The present inventors have conducted intensive studies and repeated experiments in order to solve the aforementioned problems, and as a result, have unexpectedly found that a thermoplastic polyurethane elastic fiber characterized in that it contains at least 1 metal compound selected from the group consisting of metal hydroxides, metal carbonates and metal oxides in an amount of 0.05wt% or more and 5.00wt% or less and that the metal compound contains an alkali metal or alkaline earth metal, can solve the aforementioned problems, and have completed the present invention.

Namely, the present invention is as follows.

[1] Thermoplastic polyurethane elastic fiber characterized in that it comprises at least 1 metal compound selected from the group consisting of metal hydroxide, metal carbonate and metal oxide in an amount of 0.05wt% or more and 5.00wt% or less, and that the metal compound comprises an alkali metal or alkaline earth metal.

[2] The thermoplastic polyurethane elastic fiber according to the above [1], wherein the metal compound contains an alkaline earth metal.

[3] The thermoplastic polyurethane elastic fiber according to the above [2], wherein the alkaline earth metal is magnesium.

[4] The thermoplastic polyurethane elastic fiber according to any one of the above [1] to [3], wherein the metal compound is magnesium hydroxide.

[5] The thermoplastic polyurethane elastic fiber according to any one of the above [1] to [4], wherein the polyurethane constituting the thermoplastic polyurethane elastic fiber is a polyurethane obtained by polymerizing a polymer polyol, a diisocyanate and a chain extender containing an active hydrogen compound.

[6] The thermoplastic polyurethane elastic fiber according to the above [5], wherein the chain extender is a diol having a molecular weight of 60 or more and 120 or less.

[7] The thermoplastic polyurethane elastic fiber according to the above [5] or [6], wherein the diisocyanate is 4,4' -diphenylmethane diisocyanate (MDI).

[8] The thermoplastic polyurethane elastic fiber according to any one of the above [5] to [7], wherein the proportion (Mh fraction) of the hard segment formed by the chain extender and the diisocyanate is 20% or more and 40% or less.

[9] The thermoplastic polyurethane elastic fiber according to any one of the above [5] to [8], wherein the total mole number of the chain extender and the polymer polyol is 1.001 to 1.100 times the mole number of the diisocyanate.

[10] The thermoplastic polyurethane elastic fiber according to any one of the above [1] to [9], wherein the total fineness is 160dtex or more and 2000dtex or less.

[11] The thermoplastic polyurethane elastic fiber according to any one of the above [1] to [10], which is multifilament.

[12] The thermoplastic polyurethane elastic fiber according to any one of the above [1] to [11], wherein the variation coefficient of the fineness unevenness in the filament length direction is 3.0% or more and 10.0% or less.

[13] The thermoplastic polyurethane elastic fiber according to any one of the above [1] to [12], wherein the difference between the maximum fineness and the minimum fineness in the filament length direction is 10dtex or more and 150dtex or less.

[14] The thermoplastic polyurethane elastic fiber according to any one of the above [1] to [13], wherein the flow initiation temperature of the thermoplastic polyurethane elastic fiber by a flow tester is 150 ℃ or more and 220 ℃ or less.

ADVANTAGEOUS EFFECTS OF INVENTION

The thermoplastic polyurethane elastic fiber which is one embodiment of the present invention is a thermoplastic polyurethane elastic fiber which has the above-described constitution and is excellent in resistance to yellowing by NOx gas and heat.

Detailed Description

Hereinafter, embodiments for carrying out the present invention (hereinafter referred to as "the present embodiment") will be described in detail. The present invention is not limited to the following embodiment, and can be modified and implemented within the scope of the present invention.

[ Metal Compound ]

The thermoplastic polyurethane elastic fiber of the present embodiment is characterized in that it contains at least 1 metal compound selected from the group consisting of metal hydroxide, metal carbonate and metal oxide in an amount of 0.05wt% or more and 5.00wt% or less, preferably 0.10wt% or more and 1.00wt% or less, more preferably 0.30wt% or more and 0.50wt% or less. By containing at least 1 metal compound selected from the group consisting of metal hydroxide, metal carbonate and metal oxide at 0.05wt% or more and 5.00wt% or less, resistance to yellowing by NOx gas and heat resistance become excellent. The reason why the yellowing resistance and heat resistance against NOx gas can be improved by containing at least 1 metal compound selected from the group consisting of metal hydroxides, metal carbonates and metal oxides at 0.05wt% or more and 5.00wt% or less is not clear, but the inventors have speculated as follows. The metal compound is contained in an amount of 0.05wt% or more of at least 1 selected from the group consisting of metal hydroxide, metal carbonate and metal oxide, whereby effective resistance to yellowing by NOx gas can be exhibited, and the polymer ratio in the polyurethane elastic fiber is not excessively lowered by the content of 5.00wt% or less, whereby heat resistance can be maintained.

The metal element of the foregoing metal compound preferably contains an alkali metal or an alkaline earth metal. In addition, alkaline earth metals are more preferably contained. The alkaline earth metal is preferably calcium or magnesium, and more preferably magnesium. If the metal element is an alkali metal or an alkaline earth metal, the effect of improving yellowing resistance against NOx gas becomes higher. The reason why the yellowing resistance against NOx gas can be improved by using the metal element of the metal compound as an alkaline earth metal is not clear, but the present inventors can estimate as follows. It is presumed that since the alkaline earth metal has a large charge, it is easy to adsorb NOx gas and inhibit the attack of NOx gas on the thermoplastic polyurethane elastic fiber, and therefore, the yellowing resistance of NOx gas of the thermoplastic polyurethane elastic fiber is improved.

The metal compound is particularly preferably magnesium hydroxide, since the effect of improving yellowing resistance against NOx gas becomes higher. The reason why the yellowing resistance against NOx gas can be improved by using magnesium hydroxide as the metal compound is not clear, but the present inventors have estimated as follows. It is presumed that magnesium hydroxide is a solid alkali having a high alkali strength and is likely to react with acidic NOx gas, and therefore, the yellowing resistance of NOx gas is improved.

[ Thermoplastic polyurethane ]

In the present embodiment, the thermoplastic polyurethane constituting the thermoplastic polyurethane elastic fiber is not particularly limited as long as it has a structure obtained by polymerization of, for example, diisocyanate, polymer polyol, diol, diamine, and the like, and has thermoplasticity. The polymerization method is not particularly limited. The thermoplastic polyurethane may be, for example, a polyurethane obtained by polymerizing a diisocyanate, a polymer polyol, and a low-molecular-weight diamine as a chain extender containing an active hydrogen compound, or a polyurethane obtained by polymerizing a diisocyanate, a polymer polyol, and a low-molecular-weight diol as a chain extender containing an active hydrogen compound (hereinafter, also referred to as "polyurethane urethane"). Diols and isocyanates having a trifunctional structure or more may be used within a range that does not interfere with the desired effect of the present invention. In the present specification, "thermoplastic" means a material which has reversible properties such that it can be melted by heating at a temperature equal to or lower than the decomposition temperature, shows plastic flow during a period when it is in a molten state, and solidifies by cooling. Generally, polyurethane resins begin to decompose above 230 ℃.

[ Polymer polyol ]

The polymer polyol is not limited to the following, and examples thereof include polymer diols such as polyether diols, polyester diols, and polycarbonate diols. From the viewpoint of hydrolysis resistance, polyether polyols are preferable as the polymer polyol.

Examples of the polyether polyol include polyethylene glycol, polypropylene glycol, polytetramethylene ether glycol, copolymer glycol which is a copolymer of Tetrahydrofuran (THF) and neopentyl glycol, and copolymer glycol which is a copolymer of THF and 3-methyltetrahydrofuran. These polyether polyols may be used alone or in combination of 1 or more than 2. In addition, from the viewpoint that elastic fibers excellent in elongation, stretch recovery and heat resistance can be easily obtained, the number average molecular weight of the polymer diol is preferably 1000 or more and 8000 or less. From the standpoint of light embrittlement, the polyether polyol is preferably polytetramethylene ether glycol, a copolymer glycol which is a copolymer of THF and neopentyl glycol, or a polyol obtained by blending these.

[ Diisocyanate ]

Examples of the diisocyanate include aromatic diisocyanate, alicyclic diisocyanate, and aliphatic diisocyanate. Examples of the aromatic diisocyanate include, but are not limited to, diphenylmethane diisocyanate (hereinafter also referred to as "MDI"), toluene diisocyanate, 1, 4-diisocyanatobenzene, xylylene diisocyanate, and 2, 6-naphthalene diisocyanate. Examples of the alicyclic diisocyanate and the aliphatic diisocyanate include methylenebis (cyclohexyl isocyanate) (hereinafter also referred to as "H12 MDI"), isophorone diisocyanate, methylcyclohexane 2, 4-diisocyanate, methylcyclohexane 2, 6-diisocyanate, cyclohexane 1, 4-diisocyanate, hexahydroxylylene diisocyanate, hexahydrotoluene diisocyanate, octahydro-1, 5-naphthalene diisocyanate, and the like. These diisocyanates may be used alone or in combination of 2 or more. In particular, from the viewpoint of the stretch recovery properties of the elastic fiber, the diisocyanate is preferably an aromatic diisocyanate, and more preferably MDI. In addition, MDI is produced to introduce a cyclic structure into the polymer skeleton, so that rigidity is improved and heat resistance is improved.

[ Chain extender ]

As the chain extender containing an active hydrogen compound, at least 1 selected from the group consisting of low molecular weight diamines and low molecular weight diols is preferable. In addition, as the chain extender, both hydroxyl groups and amino groups may be present in the molecule like ethanolamine. From the viewpoint of obtaining thermoplastic polyurethane suitable for melt spinning, a low molecular weight diol is preferable as the active hydrogen compound.

Examples of the low molecular weight diamine that is a chain extender containing an active hydrogen compound include hydrazine, ethylenediamine, 1, 2-propylenediamine, 1, 3-propylenediamine, 2-methyl-1, 5-pentylene diamine, 1, 2-diaminobutane, 1, 3-diaminobutane, 1-amino-3, 5-trimethyl-5-aminomethylcyclohexane, 2-dimethyl-1, 3-diaminopropane, 1, 3-diamino-2, 2-dimethylbutane, 2, 4-diamino-1-methylcyclohexane, 1, 3-pentylene diamine, 1, 3-cyclohexanediamine, bis (4-aminophenyl) phosphine oxide, hexamethylenediamine, 1, 3-cyclohexyldiamine, hexahydrometaphenylene diamine, 2-methylpentamethylene diamine, bis (4-aminophenyl) phosphine oxide, and the like.

Examples of the low molecular weight diol as the chain extender containing an active hydrogen compound include ethylene glycol, 1, 3-propanediol, 1, 4-butanediol, dihydroxyethoxybenzene, dihydroxyethylene terephthalate, 1-methyl-1, 2-ethylene glycol, 1, 6-hexanediol, and 1, 8-octanediol. These low molecular weight diols may be used alone or in combination of 1 or more than 2.

The chain extender is preferably a diol having a molecular weight of 60 to 120 from the viewpoint of elastic fiber stretch recovery and from the viewpoint of improving heat resistance and NOx gas yellowing resistance. The active hydrogen compound of the diol having a molecular weight of 60 to 120 is preferably ethylene glycol, 1, 3-propanediol, 1, 4-butanediol, 1, 6-hexanediol, 1, 8-octanediol, more preferably 1, 3-propanediol, 1, 4-butanediol, 1, 6-hexanediol, and most preferably 1, 4-butanediol.

[ Method for synthesizing thermoplastic polyurethane ]

The thermoplastic polyurethane can be obtained by a known polyurethane reaction technique, and can be produced by any of a one-pot method and a prepolymer method. In the case of the prepolymer method, a polymer polyol and a diisocyanate are added and reacted to a reaction tank having a nitrogen purge, a warm water jacket, and a stirrer, preferably at a molar ratio of 1.0:1.8 to 3.0, more preferably 1.0:2.0 to 2.5, to thereby obtain a prepolymer having isocyanate groups at both ends. Next, a chain extender is added to the isocyanate-terminated prepolymer to carry out a chain extension reaction. Thereafter, solid-phase polymerization is performed, and polyurethane having a predetermined molecular weight can be obtained. After the prepolymer and the chain extender are uniformly mixed, the solid-phase polymerization may be carried out after continuously or semi-continuously obtaining the polymer using a twin-screw extruder in the form of a cylindrical tube.

It is preferable that the total mole number of the chain extender and the polymer polyol is 1.001 to 1.100 times the mole number of the diisocyanate, since heat resistance and yellowing with NOx gas resistance can be achieved at the same time. The reason why the yellowing resistance against NOx gas and the heat resistance can be improved by setting the total mole number of the chain extender and the polymer polyol to 1.001 to 1.100 times the mole number of the diisocyanate is not clear, but the present inventors have estimated as follows. If the total mole number of the chain extender and the polymer polyol is 1.001 times or more the mole number of the diisocyanate, the amount of the diisocyanate-derived structure in the molecule that easily adsorbs NOx gas can be reduced, and therefore, the yellowing resistance of NOx gas is improved. On the other hand, if the total mole number of the chain extender and the polymer polyol is 1.100 times or less the mole number of the diisocyanate, ligand exchange between the hydroxyl group of the thermoplastic polyurethane and the metal salt is less likely to occur, and the NOx gas yellowing resistance of the metal salt is likely to be exerted, and thus the NOx gas yellowing resistance is improved. In addition, if the total mole number of the chain extender and the polymer polyol is 1.001 times or more relative to the mole number of the diisocyanate, the molecular weight of the thermoplastic polyurethane tends to increase, and thus the heat resistance also improves.

[ Method for producing thermoplastic polyurethane elastic fiber ]

The spinning method is not particularly limited as long as desired physical properties can be obtained, and examples of the method include a method of melting the pellets of thermoplastic polyurethane, mixing the polyisocyanate compound and spinning the pellets, and a method of adding a reactant of the both terminal isocyanate-based prepolymer and the active hydrogen compound to the both terminal isocyanate-based prepolymer and continuously spinning the pellets without subjecting the pellets to miniaturization, in addition to a method of feeding the pellets into an extruder and heating and melt-spinning the pellets.

The polyurethane charged into the extruder was metered by a metering pump and introduced into a spinneret. Foreign matter is removed by filtration using a metal mesh, glass beads, or the like in a spinneret as needed, and then discharged from a tube head, air-cooled in a cold air chamber, and then wound up via a godet after a treatment agent is applied.

In the spinning process, the temperature of a die, the cold air speed, the cold air temperature, the converging position and the spinning speed are regulated, and the temperature curve and the spinning tension of the fiber are tightly controlled. The temperature of the mold is preferably 180 ℃ to 220 ℃, more preferably 200 ℃ to 210 ℃. The cooling method of usual melt spinning such as a method of blowing cold air perpendicularly to the advancing direction of the yarn from just below the spinning opening is used, the air speed of the cold air is preferably 0.2m/s to 2.0m/s, more preferably 0.5m/s to 1.2m/s, and the temperature of the cold air is preferably 5 ℃ to 20 ℃, more preferably 7 ℃ to 15 ℃. As a method for forming the multifilament yarn, there is a method in which a false twister is provided between a tube head and a godet, the twisting is propagated from the lower portion by the strength of the twisting, filaments are mutually gathered, and the height of the gathering point is controlled. The false twisting method may be a general method, and an air false twisting method using an air nozzle, a ring false twisting machine that comes into contact with a rotating ring, or the like may be used.

The method of adding at least 1 metal compound selected from the group consisting of metal hydroxide, metal carbonate and metal oxide to the thermoplastic polyurethane elastic fiber of the present embodiment in an amount of 0.05wt% or more and 5.00wt% or less is not particularly limited, and examples thereof include a method of adding the thermoplastic polyurethane elastic fiber at the time of charging a raw material before the reaction of the prepolymer of the polymer polyol and the diisocyanate, a method of adding the thermoplastic polyurethane elastic fiber during the step of chain extension reaction of the prepolymer and the active hydrogen compound, and a method of adding a masterbatch containing the metal compound during spinning.

The thermoplastic polyurethane elastic fiber of the present embodiment may contain polymers other than polyurethane, additives, for example, antioxidants, light-resistant agents, ultraviolet absorbers, anti-gas discoloration agents, dyes, active agents, matting agents, pigments, lubricants, and the like, as long as the desired effects of the present invention are not lost.

From the viewpoints of ease of unwinding, workability, and the like, the thermoplastic polyurethane elastic fiber of the present embodiment may contain a treating agent such as an oil agent. Examples of the treating agent include, but are not limited to, silicone-based oils such as dimethyl silicone, mineral-oil-based oils, and combinations thereof. The method of applying the treating agent is not particularly limited, and examples thereof include a method of applying the treating agent by using an oil-impregnated roller or the like.

In the thermoplastic polyurethane elastic fiber of the present embodiment, the proportion of the hard segment formed by the chain extender and the diisocyanate (hereinafter referred to as Mh fraction) is preferably 20% or more and 40% or less, more preferably 20% or more and 35% or less, and still more preferably 22% or more and 30% or less. If the Mh fraction is 20% or more and 40% or less, the heat resistance and the yellowing resistance against NOx gas can be improved at the same time. The reason why the yellowing resistance and heat resistance against NOx gas can be improved by setting the Mh fraction to 20% or more and 40% or less is not clear, but the present inventors have estimated as follows. When the Mh fraction is 20% or more, hydrogen bonding between urethane bonds increases, heat resistance increases, and the presence rate of a metal salt around the hard segment increases, thereby improving yellowing resistance against NOx gas. On the other hand, if the Mh fraction is 40% or less, the amount of aromatic rings that adsorb NOx gas and cause yellowing is reduced when the diisocyanate contains aromatic rings, and thus the yellowing resistance of NOx gas is improved. The detailed calculation method of the Mh score is described below.

The total fineness of the polyurethane elastic fiber of the present embodiment is preferably 160dtex or more and 2000dtex or less, more preferably 300dtex or more and 1500dtex or less, and still more preferably 600dtex or more and 1000dtex or less.

The polyurethane elastic fiber of the present embodiment may be any of a monofilament and a multifilament, and is preferably a multifilament. When the polyurethane elastic fiber is multifilament, the number of filaments is preferably 14 or more and 140 or less.

The coefficient of variation in fineness unevenness in the filament length direction of the thermoplastic polyurethane elastic fiber of the present embodiment is preferably 3.0% or more and 10.0% or less, more preferably 3.0% or more and 9.5% or less, and still more preferably 3.5% or more and 9.0% or less. When the fineness variation coefficient is 3% or more and 10% or less, the yellowing resistance against NOx gas and the heat resistance can be improved at the same time. The reason why the yellowing resistance against NOx gas and the heat resistance are improved is not clear by setting the fineness fluctuation coefficient to 3.0% or more and 10.0% or less, but the present inventors have estimated as follows. If the fineness variation coefficient is 3.0% or more, light is likely to be diffusely reflected on the fiber surface, and the fiber appears opaque, so that yellowing inside the fiber is not easily recognized, and the yellowing appears slight. If the variation coefficient of fineness unevenness is 10.0% or less, yarn breakage due to heat at the fine fineness portion can be suppressed, and heat resistance can be improved. The method for controlling the variation coefficient of the fineness unevenness is not particularly limited as long as desired physical properties can be obtained, and examples thereof include a method for expanding the caliber of a spinning port used in melt spinning to generate tensile resonance, a method for increasing the ejection amount to generate shark Pi Ban (sharkkkin) and melt fracture, and a method for changing the cooling strength in the spinning step to induce yarn shaking.

The difference between the maximum fineness and the minimum fineness in the filament length direction of the thermoplastic polyurethane elastic fiber of the present embodiment is preferably 10dtex or more and 150dtex or less, more preferably 15dtex or more and 100dtex or less, and still more preferably 20dtex or more and 80dtex or less. If the difference between the maximum fineness and the minimum fineness is 10dtex or more and 150dtex or less, the yellowing resistance and heat resistance against NOx gas can be improved at the same time. The reason why the NOx gas yellowing resistance and the heat resistance are improved is not clear by making the difference between the maximum fineness and the minimum fineness be 10dtex or more and 150dtex or less is estimated as follows. If the difference between the maximum fineness and the minimum fineness is 10dtex or more, light is likely to be diffusely reflected on the fiber surface, and the fiber appears opaque, so that yellowing inside the fiber is not easily recognized, and the yellowing appears slight. If the difference between the maximum fineness and the minimum fineness is 150dtex or less, breakage of the fine fineness due to heat can be suppressed, and heat resistance can be improved. The method for controlling the fineness difference is not particularly limited as long as desired physical properties can be obtained, and examples thereof include a method for expanding the caliber of a spinning port used in melt spinning to generate tensile resonance, a method for increasing the ejection amount to generate shark marks and melt cracks, and a method for changing the cooling strength in the spinning step to induce shaking of filaments.

In the thermoplastic polyurethane elastic fiber of the present embodiment, the outflow start temperature based on the flow tester is preferably 150 ℃ or more and 220 ℃ or less, more preferably 150 ℃ or more and 200 ℃ or less, from the viewpoint of improving heat resistance and NOx gas yellowing resistance. The reason why the heat resistance and the yellowing resistance against NOx gas can be improved by setting the outflow start temperature to 150 ℃ to 220 ℃ both inclusive is not clear, and the present inventors have estimated as follows. The heat resistance can be improved by reducing the structural change of the thermoplastic polyurethane by heat by setting the outflow start temperature to 150 ℃ or higher, while the NOx gas yellowing resistance can be improved by setting the outflow start temperature to 220 ℃ or lower, whereby the viscosity at the time of melting is reduced and the wettability is improved, whereby the metal salt is uniformly dispersed.

Examples

The present invention will be specifically described with reference to the following examples and comparative examples, but the scope of the present invention is not limited to the examples.

First, the evaluation methods of physical properties and the like used in examples and comparative examples will be described.

< Quantification of constituent Components of thermoplastic polyurethane >

The structures of the chain extender containing an active hydrogen compound and the diisocyanate constituting the thermoplastic polyurethane contained in the thermoplastic polyurethane elastic fiber were determined using NMR. Specifically, NMR was measured under the following conditions to determine the structures of the diisocyanate and the chain extender. The structures of the diisocyanate and the chain extender can be judged from the peak positions determined based on NMR.

Measuring device Bruker Biospin Avance600,600

Determination of the core ¹ H

Resonance frequency 600MHz

The cumulative number of times is 256 times

Measuring temperature, room temperature

Solvent deuterated dimethylformamide

Measured concentration 1.5 wt%

Reference to chemical shift dimethylformamide (8.0233 ppm)

< Method of calculating the ratio of the total mole number of the chain extender to the polymer polyol to the mole number of diisocyanate (hereinafter referred to as OH/NCO)

The OH/NCO of the thermoplastic polyurethane elastic fiber is calculated from the integral value of this peak measured based on NMR, using the following formula (1):

OH/nco= { (hh+hs)/4 }/(Hi/x)..formula (1)

In the formula,

Hh integral value of methylene-derived active hydrogen Compound adjacent to urethane bond

Hs integral value derived from methylene of Polymer polyol adjacent to urethane bond

Hi Integrated value derived from hydrogen Compound in diisocyanate

X is the total hydrogen content of the diisocyanate.

< Method for quantifying the proportion of hard segment (Mh fraction) >)

The Mh fraction of the thermoplastic polyurethane elastic fiber is calculated by solving the simultaneous equations of the following formulas (2) to (5):

ms= { Mdo+ Mdi (N1-N0) }/(N1-N0-1) -2 Mdi..formula (2)

Mh= { Mda (N1-1) + Mdi xn0 }/(N1-N0-1) +2 Mdi..formula (3)

N0= 0.03806N1 ⁴-0.3997N1³+1.617N1²-2.144N1¹ +0.8795 once again, the method (4)

Mh fraction (%) = { Mh/(ms+mh) } ×100..formula (5)

In the formula,

Ms number average molecular weight of the Soft segment fraction

Mdo number average molecular weight of Polymer polyol

Mdi molecular weight of isocyanate

N1 molar ratio of isocyanate to Polymer polyol

N0 molar ratio of unreacted isocyanate to Polymer polyol

Mh number average molecular weight of hard segment portion

Mda, molecular weight of chain extender (number average molecular weight when more than 2 are used in combination)

Mdi molecular weight of isocyanate.

< Method for identifying and quantifying Metal Compounds >

The thermoplastic polyurethane elastic fiber is wound around a glass plate, analyzed by XRD (physical um-IV), and the chemical composition of the metal compound contained therein can be identified by comparing the analysis spectrum with the data in the database. After the identification of the metal compound by XRD, a sample was produced by winding a PP film having a hole formed around a thermoplastic polyurethane elastic fiber without any gap, and analysis was performed by XRF (physical ZSX-100 e), whereby the content of the metal compound was quantified based on the detection intensity of the element constituting the metal compound. In the quantitative analysis, a standard curve obtained using the same metal compound as that contained therein can be used as needed.

< Measurement of flow-out initiation temperature of thermoplastic polyurethane elastic fiber >

The flow-out initiation temperature of the thermoplastic polyurethane elastic fiber was measured using a flow tester CFT-500D (manufactured by Shimadzu corporation). The thermoplastic polyurethane elastic fiber was sampled 1.5g at a time without performing a preliminary treatment such as removal of a treating agent such as an oil agent, and the outflow start temperature was measured. The die (nozzle) was a die having a diameter of 0.5mm and a thickness of 1.0mm, an extrusion load of 49N was applied, the temperature was raised to 250℃at a constant speed of 3℃/min after a preheating time of 240 seconds at an initial set temperature of 120℃and a curve of the stroke length (mm) and the temperature at that time was obtained. As the temperature increases, the polymer within the toner is heated, and begins to flow out of the mold. The temperature at this time was set as the outflow start temperature.

< Method for measuring variation coefficient of fineness unevenness >

In the measurement of the coefficient of variation in fineness, the rotation speed of the two godets was adjusted so that the thermoplastic polyurethane elastic fiber was stretched 2 times, and the following devices were installed between the godets. The outer diameter of the elastic fiber was measured by a laser beam from two directions perpendicular to each other, and the ratio of the average deviation of the diagonal length calculated according to the Pythagorean theorem to the average value was set as the fineness unevenness coefficient. The measured data used an average of 50000 data measured at 160 points/sec.

LS9006D (manufactured by Kien Co., ltd.)

Measuring species, outer diameter

Minimum display unit 0.0001mm

Number of measurements 50000

Accumulation period:. Times.100

< Method for measuring fineness >

In the measurement of fineness, a thermoplastic polyurethane elastic fiber was vertically cut, a yarn cross section was observed using the following apparatus/conditions, the total cross section of the yarn was calculated by automatic area measurement, and the fineness per unit length was calculated using the following formula (6):

d=d×1.1 (g/cm ³)×10⁶..formula (6))

In the formula {, D is fineness (dtex), and D is total cross-sectional area of the yarn (cm ²). }

Measurement device VHX-7000 (manufactured by Kien's Co., ltd.)

Using lenses VH-Z100R

Multiplying power 500 times

Measurement automatic area measurement

Extraction method of brightness

< Method for measuring the difference between the maximum and minimum deniers of polyurethane elastic fiber >

In the measurement of the difference between the maximum fineness and the minimum fineness, the thermoplastic polyurethane elastic fiber was cut vertically, the yarn cross section was observed using the following apparatus/conditions, the total cross section of the yarn was calculated by automatic area measurement, the fineness per unit length at 10 positions was calculated by the above formula (6) at intervals of 5mm in the yarn length direction, and the difference between the maximum fineness and the minimum fineness at this time was calculated.

Measurement device VHX-7000 (manufactured by Kien's Co., ltd.)

Using lenses VH-Z100R

Multiplying power 500 times

Measurement automatic area measurement

Extraction method of brightness

< Method for evaluating Heat resistance >

The thermoplastic polyurethane elastic fiber was held in a state stretched to 2 times, and the time (number of thermal cutting seconds) until yarn breakage occurred when pressed to a heat source of 110 ℃ was evaluated as an index of heat resistance.

< Method for evaluating yellowing resistance to NOx gas >

1. Delta YI value

The yellowing was evaluated by using a thermoplastic polyurethane elastic fiber according to JIS-L-0855, a method for testing the color fastness to nitrogen oxide, and a method for testing the weakness. In the determination, the yellow YI value by a Macbeth color measuring machine (manufactured by Macbeth Co.) was compared with the untreated sample YI0, and evaluated in accordance with the DeltaYI value obtained by the following formula (7):

Δyi=yi-yi0..formula (7)

The smaller the Δyi value, the less likely to yellow, and the larger the Δyi value, the more likely to yellow.

2. Identification of yellowing

The thermoplastic polyurethane elastic fiber which had been subjected to yellowing by the method of the above 1 was compared with a color scale, and an evaluation score was marked on 10 scale. Specifically, the color scale closest to the color of the thermoplastic polyurethane elastic fiber having yellowing was selected by 10 persons aged 20 years, 2 persons aged 30 to 60 years, and 18 persons in total, and the average value was set as the evaluation score of the yellowing identification. The color scale and the evaluation score used are as follows, and a larger evaluation score indicates less yellowing.

1 Min FFD500

# FFD91A 2 min

# FFDD33:3 min

4 Minutes of # FFE14D

# FFE666:5 min

# FFEA80:6 min

# FFEE99:7 min

# FFF2B3:8 minutes

# FFF7CC:9 min

# FFFBE6:10 min

The Δyi value and the yellowing resistance were evaluated as NOx gas yellowing resistance. Since the Δyi value is not affected by the human visibility, but the yellowing is affected by the human visibility, the yellowing resistance of the NOx-resistant gas can be evaluated based on the human visibility by comparing the yellowing resistance of the samples having the same Δyi value.

Example 1

< Synthesis of thermoplastic polyurethane resin >

2400G of polytetramethylene ether glycol having a number average molecular weight of 1800 was reacted with 750.78g of 4,4' -diphenylmethane diisocyanate under dry nitrogen atmosphere at 60℃with stirring for 3 hours to give a polyurethane prepolymer terminated with terminal isocyanate. To the polyurethane prepolymer was added 151.20g of 1, 4-butanediol and stirred for 15 minutes to give a polyurethane having a viscosity of 2000 poise (30 ℃).

Thereafter, the polyurethane was discharged to a teflon (registered trademark) tray, and annealed in a hot air oven at 110 ℃ for 16 hours in a state where the polyurethane was put into the tray, to obtain a thermoplastic polyurethane resin.

< Preparation of masterbatch >

The thermoplastic polyurethane resin thus obtained was pulverized into powder of about 3mm by a pulverizer UG-280 manufactured by HORIE. After drying the crushed chips to a water content of 100ppm by a dehumidification dryer at a temperature of 110 ℃, polyurethane resin powder and magnesium hydroxide are charged into a hopper at a predetermined ratio, melted in an extruder to prepare strands, and cooled in a water bath at a temperature of 20 ℃, and granulated by a plastic processing machine SCF-100 type from the company of the chemical engineering machine to obtain a master batch containing 10wt% of magnesium hydroxide as an active ingredient.

< Production of thermoplastic polyurethane elastic fiber >

The polyurethane resin powder containing magnesium hydroxide obtained by mixing the thermoplastic polyurethane resin powder and the master batch of magnesium hydroxide at a weight ratio of 95:5 was measured and pressurized by a gear pump provided at the head, and after filtration by a filter, the polyurethane resin powder was discharged from a nozzle having a diameter of 0.23mm and 60 holes at a discharge amount of 620dtex under the condition that the die temperature was 210 ℃. Thereafter, the melt spinning is performed by blowing off cold air from a cold air chamber in which a cold air temperature is adjusted to 15 to 17 ℃ and a cold air speed is adjusted to 0.8 to 1.0m/s, and vertically contacting the fibers. Thereafter, the multifilament was spread and twisted using a ring false twister, and a treatment agent containing polydimethylsiloxane and mineral oil as main components was applied to the multifilament and wound around a paper tube to obtain a filament body of a thermoplastic polyurethane elastic fiber of 620dtex/60 filaments. The thermoplastic polyurethane elastic fiber contained 0.50wt% of magnesium hydroxide, 24% of Mh fraction, 4.0% of variation coefficient of fineness unevenness, 1.010% of OH/NCO, 600 seconds or more of thermal cutting, 8% of DeltaYI value of the thermoplastic polyurethane elastic fiber, 30dtex of difference between maximum fineness and minimum fineness, 160 ℃ of outflow start temperature, and 10 minutes of yellowing resistance evaluation. The results are also shown in table 1 below.

Examples 2 to 6

A thermoplastic polyurethane elastic fiber was obtained in the same manner as in example 1, except that the ratio of the polyurethane resin to the master batch was adjusted to increase or decrease the amount of magnesium hydroxide contained in the polyurethane elastic fiber. The results are shown in table 1 below.

Examples 7 to 12

Thermoplastic polyurethane elastic fibers were obtained in the same manner as in example 1, except that the metal compound was changed to magnesium carbonate (example 7), magnesium oxide (example 8), calcium hydroxide (example 9), calcium carbonate (example 10), sodium carbonate (example 11), and potassium carbonate (example 12). The results are shown in table 1 below.

Examples 13 to 17

Thermoplastic polyurethane elastic fibers were obtained in the same manner as in example 1, except that the chain extender containing an active hydrogen compound was changed to ethylene glycol (example 13), 1, 3-propylene glycol (example 14), 1, 6-hexanediol (example 15), 1, 8-octanediol (example 16), and 1, 10-decanediol (example 17). The results are shown in table 1 below.

Examples 18 and 19

Thermoplastic polyurethane elastic fibers were obtained in the same manner as in example 1, except that methylene bis (cyclohexyl isocyanate) (H12 MDI) (example 18) and 1, 6-Hexamethylene Diisocyanate (HDI) (example 19) were used instead. The results are shown in table 1 below.

Examples 20 to 26

Thermoplastic polyurethane elastic fibers were obtained in the same manner as in example 1, except that the molar ratio of the polymer polyol to the diisocyanate was adjusted to increase or decrease the Mh fraction of the thermoplastic polyurethane elastic fibers. The results are shown in table 1 below.

TABLE 1

Examples 27 to 33

Thermoplastic polyurethane elastic fibers were obtained in the same manner as in example 1, except that the molar ratio of the polymer polyol, diisocyanate, and diol was changed to OH/NCO of the thermoplastic polyurethane elastic fibers. The results are shown in table 2 below.

Examples 34 to 41

Thermoplastic polyurethane elastic fibers were obtained in the same manner as in example 1, except that the yarn-spinning temperature, the yarn-spinning diameter, the ejection amount, the cooling conditions, and the winding conditions during the spinning were adjusted to change the coefficient of variation in fineness of the thermoplastic polyurethane elastic fibers. The results are shown in table 2 below.

Examples 42 to 49

Thermoplastic polyurethane elastic fibers were obtained in the same manner as in example 1, except that the difference in fineness (maximum fineness-minimum fineness) of the thermoplastic polyurethane elastic fibers was changed by adjusting the spinning temperature, the spinning opening diameter, the ejection amount, the cooling condition, and the winding condition during spinning. The results are shown in table 2 below.

TABLE 2

Examples 50 to 54

Thermoplastic polyurethane elastic fibers were obtained in the same manner as in example 1, except that the molecular weight of the thermoplastic polyurethane was adjusted by adjusting the molecular weight of the polymer polyol, and the outflow starting temperature of the thermoplastic polyurethane elastic fibers was changed. The results are shown in Table 3 below.

Comparative example 1

Thermoplastic polyurethane elastic fibers were obtained in the same manner as in example 1, except that no metal compound was added. The results are shown in Table 3 below.

Comparative example 2

Thermoplastic polyurethane elastic fibers were obtained in the same manner as in example 1, except that the amount of magnesium hydroxide contained in the polyurethane elastic fibers was changed to 10.0wt% by adjusting the addition amount of the master batch. The results are shown in Table 3 below.

Comparative examples 3 to 6

Thermoplastic polyurethane elastic fibers were obtained in the same manner as in example 1, except that the metal compound was changed to magnesium stearate (comparative example 3), calcium stearate (comparative example 4), zinc oxide (comparative example 5), and aluminum hydroxide (comparative example 6). The results are shown in Table 3 below.

TABLE 3

Industrial applicability

The thermoplastic polyurethane elastic fiber of the present invention can be suitably used for clothing such as underwear, socks, tights, and sanitary materials such as gather members and diapers.

Claims (14)

1. Thermoplastic polyurethane elastic fiber characterized in that it comprises at least 1 metal compound selected from the group consisting of metal hydroxide, metal carbonate and metal oxide in an amount of 0.05wt% or more and 5.00wt% or less, and that the metal compound comprises an alkali metal or alkaline earth metal.

2. The thermoplastic polyurethane elastic fiber according to claim 1, wherein the metal compound comprises an alkaline earth metal.

3. The thermoplastic polyurethane elastic fiber according to claim 2, wherein the alkaline earth metal is magnesium.

4. The thermoplastic polyurethane elastic fiber according to any one of claims 1 to 3, wherein the metal compound is magnesium hydroxide.

5. The thermoplastic polyurethane elastic fiber according to any one of claims 1 to 3, wherein the polyurethane constituting the thermoplastic polyurethane elastic fiber is a polyurethane obtained by polymerizing a polymer polyol, a diisocyanate and a chain extender containing an active hydrogen compound.

6. The thermoplastic polyurethane elastic fiber according to claim 5, wherein the chain extender is a diol having a molecular weight of 60 or more and 120 or less.

7. The thermoplastic polyurethane elastic fiber according to claim 5, wherein the diisocyanate is 4,4' -diphenylmethane diisocyanate (MDI).

8. The thermoplastic polyurethane elastic fiber according to claim 5, wherein a proportion (Mh fraction) of a hard segment formed by the chain extender and the diisocyanate is 20% or more and 40% or less.

9. The thermoplastic polyurethane elastic fiber according to claim 5, wherein the total number of moles of the chain extender and the polymer polyol is 1.001 times or more and 1.100 times or less relative to the number of moles of the diisocyanate.

10. The thermoplastic polyurethane elastic fiber according to any one of claims 1 to 3, wherein the total fineness of the thermoplastic polyurethane elastic fiber is 160dtex or more and 2000dtex or less.

11. The thermoplastic polyurethane elastic fiber according to any one of claims 1 to 3, which is multifilament.

12. The thermoplastic polyurethane elastic fiber according to any one of claims 1 to 3, wherein the coefficient of variation of fineness unevenness in the filament length direction is 3.0% or more and 10.0% or less.

13. The thermoplastic polyurethane elastic fiber according to any one of claims 1 to 3, wherein a difference between a maximum fineness and a minimum fineness in a filament length direction is 10dtex or more and 150dtex or less.

14. The thermoplastic polyurethane elastic fiber according to any one of claims 1 to 3, wherein the flow initiation temperature of the thermoplastic polyurethane elastic fiber based on a flow tester is 150 ℃ or more and 220 ℃ or less.