Polyurethane urea elastic yarn with excellent heat resistance and rebound resilience and preparation method thereof

Abstract

The invention relates to a preparation method of polyurethane-urea elastic yarn, the polyurethane-urea elastic yarn is composed of polyol and diisocyanate polymer, and the preparation method is characterized in that the polyol and diisocyanate are adopted to prepare a prepolymer with an end-capping ratio (CR) of 1.30-1.65, the addition amount of trimethylolpropane is 0.2-5.0 wt% relative to the weight of the polyurethane-urea yarn, the addition amount of trimethylolpropane is 0.2-5.0 wt% relative to the weight of the polyurethane-urea yarn, and the addition amount of trimethylolpropane is 0.2-5.0 wt% relative to the weight of the polyurethane-urea yarn. According to the present invention, the present invention relates to a polyurethane urea elastic yarn having improved heat resistance and resilience while maintaining stretch properties (elongation), and to a method for preparing the same.

Description

Technical Field

[0001] The present invention relates to a polyurethane-urea elastic yarn having excellent heat resistance and resilience, and a method for producing the same. More specifically, the present invention relates to a polyurethane-urea elastic yarn and a method for producing the same, which improve the problems caused by the addition of trimethylolpropane, thereby improving heat resistance and resilience without causing a decrease in elongation. Background Art

[0002] Polyurethane-urea elastic yarns have excellent elastic properties and are therefore widely used in various products that require stretchability or close-fitting properties, such as underwear, stockings, sportswear, compression garments, and diapers.

[0003] Polyurethane-urea elastic yarns are generally produced by reacting a polyol with an excess of a diisocyanate compound to obtain a prepolymer having isocyanate groups at both ends of the polyol, adding a chain extender to a solution containing the obtained prepolymer, reacting with a chain terminator to form a polyurethane-urea spinning dope, and then subjecting it to dry-wet spinning.

[0004] Generally, when polyurethane-urea elastic yarns are used in the general apparel field, they are interwoven with other materials such as nylon, polyester, cotton, silk, and wool, and then processed through manufacturing processes such as cutting, sewing, and finishing to become products. In such a case of interweaving with other materials, after being woven with the corresponding yarns (nylon, cotton, silk, wool, etc.), problems such as a decrease in the strength and resilience of the fabric due to thermal brittleness at high temperatures occur during post-processing. In addition, due to the poor heat resistance of polyurethane-urea elastic yarns, it is difficult to dye them at a high temperature of about 130 °C when blended with other materials. Therefore, although they have a wide range of uses, their uses are also limited.

[0005] To solve this problem, the present applicant proposed a method for producing a polyurethane-urea elastic yarn in Korean Patent Publication No. 2014-0094357, in which the molecular chains are connected in a crosslinked manner so that the resilience to physical deformation is increased compared to conventional yarns. The method is characterized in that trimethylolpropane is added to a polyurethane-urea polymer to prepare a polyurethane-urea spinning dope, and then it is spun.

[0006] However, in this technology, when trimethylolpropane is added during the first polymerization, second polymerization, or after the second polymerization of the polyurethane-urea elastic yarn, due to crosslinking between polymer chains, its solubility in the solvent decreases, and during the curing process of the polymer, the viscosity increase rate of the polymer is relatively high, making process control difficult. At this time, although the viscosity increase rate of the polymer can be adjusted by reducing the solids content of the polymer, there is a problem of increased energy consumption during dry spinning or wet spinning as the solids content of the polymer decreases.

[0007] In addition, polyurethane-urea elastic yarns using trimethylolpropane have the advantage of improved yarn strength and resilience due to the cross-linking effect of trimethylolpropane in terms of physical properties. However, their elongation at break decreases, making it difficult to exhibit the unique properties of polyurethane-urea elastic yarns. Summary of the Invention

[0008] [Technical Problem]

[0009] In order to overcome the problems existing in the above-mentioned prior art, one object of the present invention is to provide a method for preparing a polyurethane-urea elastic yarn, which can maintain the unique physical properties of the polyurethane-urea elastic yarn while having excellent heat resistance and resilience by solving the problems existing when trimethylolpropane is applied to the polyurethane-urea elastic yarn.

[0010] Another object of the present invention is to provide a polyurethane-urea elastic yarn that not only ensures elongation at break but also has excellent heat resistance and resilience.

[0011] Another object of the present invention is to provide a fabric containing the polyurethane-urea elastic yarn.

[0012] [Technical Solution]

[0013] The present invention relates to a method for preparing a polyurethane-urea elastic yarn, which is characterized in that by solving the problems existing when trimethylolpropane is applied as an additive to a polyurethane-urea polymer, it is conventionally applied to the polyurethane-urea elastic yarn, thereby improving the heat resistance and resilience of the yarn.

[0014] That is, the present invention relates to a method for preparing a polyurethane-urea elastic yarn, wherein the polyurethane-urea elastic yarn is composed of a polyol and a diisocyanate polymer, and is characterized in that a prepolymer with a capping ratio (CR) of 1.30 to 1.65 is prepared by using the polyol and the diisocyanate, and the addition amount of trimethylolpropane is 0.2 to 5.0% by weight based on the weight of the polyurethane-urea yarn.

[0015] The method of the present invention includes:

[0016] A first polymerization step of mixing the polyol and the diisocyanate at a capping ratio (CR) of 1.30 to 1.65 to form a prepolymer;

[0017] After adding a solvent to the obtained prepolymer, contacting it with one or more chain extenders for a second polymerization to obtain a polyurethane-urea spinning dope; and

[0018] A step of spinning the polyurethane-urea spinning dope to form a polyurethane-urea elastic yarn,

[0019] In the method, trimethylolpropane is applied in the first polymerization step, in the second polymerization step, or after the second polymerization step.

[0020] In the present invention, the addition amount of trimethylolpropane makes the viscosity increase rate within 100%. The addition amount of trimethylolpropane makes the ratio of the hard segment to the soft segment within the range of 4:96 to 10:90 by weight.

[0021] Non-limiting examples of the diisocyanate that can be used in the present invention include one or more selected from the following group: 4,4'-diphenylmethane diisocyanate, 1,5'-naphthalene diisocyanate, 1,4'-phenylene diisocyanate, hexamethylene diisocyanate, 1,4'-cyclohexane diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, or isophorone diisocyanate.

[0022] The polyol that can be used in the present invention can be one or more selected from the following group: polytetramethylene ether glycol, polypropylene glycol, polyethylene glycol, polycarbonate diol, a copolymer of a mixture of alkylene oxides and lactone monomers and polytetramethylene ether glycol, or a copolymer of 3-methyl-tetrahydrofuran and tetrahydrofuran.

[0023] The chain extender is one or more selected from the following group: ethylenediamine, 1,2-propanediamine, 1,3-propanediamine, 1,4-butanediamine, 2,3-butanediamine, 1,5-pentanediamine, 1,6-hexanediamine, and 1,4-cyclohexanediamine, and the chain terminator is selected from the following group: diethylamine, monoethanolamine, cyclohexylamine, and dimethylamine.

[0024] The organic solvent used in the preparation of the polymer solution can be N,N'-dimethylformamide, N,N'-dimethylacetamide, dimethyl sulfoxide, or N-methylpyrrolidone (NMP), etc.

[0025] In the present invention, other additives can be further added to the polyurethane-urea spinning dope before spinning, and the additives are selected from a delustering agent, an ultraviolet stabilizer, an antioxidant, an NOx gas yellowing inhibitor, an anti-sticking agent, a dye accelerating agent, and an anti-chlorine agent.

[0026] On the other hand, the present invention relates to a polyurethane-urea elastic yarn prepared by the method of the present invention, which is characterized in that it contains 0.2 to 5.0% by weight of trimethylolpropane based on the weight of the polyurethane-urea yarn.

[0027] In the polyurethane-urea elastic yarn of the present invention, the elongation rate of the yarn is 450% or more, the heat resistance is 60% or more, and the elastic recovery rate is 26% or less.

[0028] The polyurethane-urea elastic yarn of the present invention may consist of the following: (a) polytetramethylene ether glycol; (b) 4,4'-methylenebis(phenyl isocyanate); and (c) a reaction product of a polyurethane-urea containing a mixture of chain extenders including ethylenediamine and diethylamine, and, relative to the weight of the polyurethane-urea yarn, contains 0.2 to 5.0 weight percent of trimethylolpropane.

[0029] Another aspect of the present invention relates to a fabric comprising the polyurethane-urea elastic yarn of the present invention.

[0030] [Effects of the Invention]

[0031] The polyurethane-urea elastic yarn of the present invention can improve the problems brought about by the addition of trimethylolpropane, and thus can provide a polyurethane-urea elastic yarn and a preparation method thereof that both improve heat resistance and resilience and maintain unique stretch properties (elongation).

[0032] The polyurethane-urea elastic yarn of the present invention has sufficient heat resistance to support elastic properties, so there are fewer restrictions on the heat conditions of processing, and it can provide products combined with all corresponding yarns commonly used in fiber products using polyurethane-urea elastic yarns. Detailed Embodiments

[0033] Hereinafter, the present invention will be described in more detail.

[0034] One aspect of the present invention relates to a method for preparing a polyurethane-urea elastic yarn, the polyurethane-urea elastic yarn being composed of a polyol and a diisocyanate polymer, characterized in that a prepolymer with a blocking ratio (CR) of 1.30 to 1.65 is prepared using a polyol and a diisocyanate, and the addition amount of trimethylolpropane is 0.2 to 5.0 weight percent relative to the weight of the polyurethane-urea yarn.

[0035] The method of the present invention specifically includes: a first polymerization step of mixing a polyol and a diisocyanate with a blocking ratio (CR) of 1.30 to 1.65 to form a prepolymer; a step of adding a solvent to the obtained prepolymer and then contacting it with one or more chain extenders for a second polymerization to obtain a polyurethane-urea spinning dope; and a step of spinning the polyurethane-urea spinning dope to form a polyurethane-urea elastic yarn. In the method of the present invention, trimethylolpropane can be added in the first polymerization step, in the second polymerization step, or after the second polymerization step.

[0036] In the first polymerization step, the polyol is reacted with an excess of diisocyanate to form an isocyanate-terminated polyurethane or polyurethane-urea prepolymer.

[0037] In the second polymerization step, the prepolymer is diluted in a solvent and chain-extended with a short-chain diol or diamine to increase the polymer chain length. At this time, there is no particular limitation on the types of solvents that can be used. For example, N,N'-dimethylformamide, N,N'-dimethylacetamide, dimethyl sulfoxide, N-methylpyrrolidone (NMP), or a mixed solvent thereof can be used.

[0038] A chain terminator can be used to control the molecular weight of the polymer. In this conventional process, the soft segment is formed during the prepolymer formation step, while the hard segment is formed during the chain extension step.

[0039] Next, the prepared polyurethane urea spinning dope is made into polyurethane urea elastic yarn by dry spinning, wet spinning, or melt spinning techniques. In a non-limiting example, the polyurethane urea elastic yarn is prepared by dry spinning.

[0040] In order to provide the desired molecular weight ratio of the hard segment to the soft segment, it is necessary to control the molecular weight of the chain-extending polyol and the capping ratio during the preparation of the prepolymer. In the present invention, the prepolymer is prepared by using a capping ratio (CR) of 1.30 to 1.65 for the polyol and the diisocyanate. When the capping ratio is less than 1.30, due to the high content of the soft segment, the viscosity does not increase after polymerization, resulting in difficulties in process application. When the capping ratio is greater than 1.65, due to excessive crosslinking, there are difficulties in the polymerization process application, and the elongation of the yarn is low. Therefore, there is a problem that the spandex characteristics cannot be demonstrated.

[0041] Trimethylolpropane has three hydroxyl (-OH) functional groups. The hydroxyl functional groups combine with the isocyanate groups (-NCO groups) of the spandex polymer to form a crosslinked structure, which plays a role in improving the heat resistance and resilience (elastic recovery rate) of the polyurethane urea elastic yarn.

[0042] When the capping ratio (CR) of the existing polyol and diisocyanate is about 1.7, it is difficult to apply the content of trimethylolpropane above 3.0 wt%. When the capping ratio is adjusted to the range of 1.30 to 1.65, the content of trimethylolpropane can be applied up to 5.0 wt%. When the capping ratio is 1.7, considering the increase in the viscosity aging rate and the decrease in the elongation rate, etc., it is difficult to apply the content of trimethylolpropane above 3.0 wt%. However, when the capping ratio is reduced to 1.30 to 1.65, the viscosity aging rate decreases and the elongation rate increases, leaving room for the increase in the viscosity aging rate and the decrease in the elongation rate caused by the application of trimethylolpropane. Therefore, the content of trimethylolpropane can be applied up to 5%.

[0043] In the present invention, the addition amount of trimethylolpropane is preferably about 0.2 to 5.0% by weight relative to the total solid content. When the content of trimethylolpropane is less than 0.2% by weight relative to the yarn weight, the improvement effects on the elastic recovery rate and heat resistance are extremely small. On the contrary, when the content of trimethylolpropane is greater than 5% by weight, the polymerization reaction cannot proceed normally.

[0044] When adding the trimethylolpropane, the viscosity increase rate after addition is within 100%.

[0045] Preferably, when adding the trimethylolpropane, the ratio of the hard segment to the soft segment is in the range of 4:96 to 10:90 by weight.

[0046] The polyol can be one or more selected from the following group: polytetramethylene ether glycol, polypropylene glycol, polyethylene glycol, polycarbonate diol, a copolymer of a mixture of an alkylene oxide and a lactone monomer and polytetramethylene ether glycol, or a copolymer of 3-methyl-tetrahydrofuran and tetrahydrofuran. As the polyol, polytetramethylene ether glycol is preferred due to its good stretching properties (elastic recovery rate and elongation) and high cost performance. These polyols can be used alone or in combination of two or more.

[0047] In the present invention, in order to achieve the required elongation, strength, heat resistance, etc. when making elastic yarns, the number average molecular weight of the polyol is preferably 1000 to 8000, more preferably 1800 to 6000. By using a polymer diol having a molecular weight in this range, elastic yarns with excellent elongation, strength, elastic recovery force, and heat resistance can be obtained.

[0048] The diisocyanate that can be used in the present invention is not particularly limited. For example, one or more selected from the following group can be used: 4,4'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, 1,5'-naphthalene diisocyanate, 1,4'-phenylene diisocyanate, hexamethylene diisocyanate, 1,4'-cyclohexane diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, isophorone diisocyanate, and their mixtures.

[0049] In the present invention, diamines can be used as chain extenders. For example, they can be one or more selected from the following group, but not limited to: ethylenediamine, 1,2-propanediamine, 1,3-propanediamine, 1,4-butanediamine, 2,3-butanediamine, 1,5-pentanediamine, 1,6-hexanediamine, 1,4-cyclohexanediamine, and their combinations.

[0050] As a chain terminator, amines having a single functional group can be used, such as diethylamine, monoethanolamine, cyclohexylamine, dimethylamine, etc. When preparing the polyurethane urea of the present invention, the chain extender and the chain terminator can be added at one time or added more than twice. Preferably, the chain extender and the chain terminator are dissolved in a suitable solvent.

[0051] In addition, in the present invention, in order to prevent the discoloration and deterioration of physical properties of the polyurethane urea due to ultraviolet rays, atmospheric haze, heat treatment processes accompanying the processing of polyurethane urea elastic yarns, etc., a combination of a sterically hindered phenolic compound, a benzofuranone compound, a semicarbazide compound, a benzotriazole compound, a high molecular weight tertiary amine stabilizer, etc. can be added to the spinning dope.

[0052] The polyurethane urea elastic yarn may contain additives such as stabilizers and pigments, but these additives should not reduce the advantages of the present invention. These additives include benzotriazole stabilizers, ultraviolet absorbers, other light-resistant agents, antioxidants, delustering agents, anti-sticking agents, dyes and mordants, lubricants (e.g., mineral oil and silicone oil), deodorants, and antistatic agents. Other examples of additives include Mexacryl( 2462 (DuPont (E.I. du Pont de Nemours and Company)), a polymer of bis(4-isocyanatocyclohexyl)methane and 3-tert-butyl-3-aza-1,5-pentanediol), titanium oxide, zinc oxide, magnesium stearate, barium sulfate, hydrotalcite, a mineral mixture of huntite and hydromagnesite, and fungicides containing silver, zinc or their compounds, etc. The addition method of these other additives is not particularly limited, and all conventional methods such as proper mixing can be adopted.

[0053] In addition, from the viewpoint of obtaining fibers with high durability and strength, the molecular weight of the polyurethane constituting the polyurethane urea elastic yarn of the present invention is preferably in the range of 40,000 or more and 150,000 or less in terms of number average molecular weight. And, the molecular weight is measured by GPC and converted by polystyrene.

[0054] Next, the prepared polyurethane urea spinning dope is dry-spun to obtain a polyurethane urea elastic yarn having an elongation of 450% or more, a heat resistance of 60% or more, and an elastic recovery rate of 26% or less. In the present invention, the elongation is measured using a MEL [Automatic Tensile Tester for Elastic Yarns STATIA MEL, Textechno] device according to the general method of ASTM D2731-72.

[0055] In the polyurethane-urea elastic yarn prepared by the present invention, an important physical property of the elastic fiber of the yarn is the "elastic recovery rate" (percent set), that is, the degree to which the fiber can return to its original length after being stretched. Any excess length is expressed as the degree of elastic recovery rate, and the smaller this value is, the better. The elastic recovery rate of the polyurethane-urea elastic yarn of the present invention is 26% or less.

[0056] The polyurethane-urea elastic yarn of the present invention can be compounded with other fiber materials to make fabrics such as knitted fabrics and woven fabrics. These fabrics can be clothing products, such as corsets, bras, underwear, leggings, pantyhose, bodysuits, swimsuits, sportswear, coats, elastic linings, etc. The fiber materials used in the fabrics made of the polyurethane-urea elastic yarn of the present invention are not particularly limited, and examples can be polyamide fibers such as nylon 6 or nylon 66; polyester fibers such as polyethylene terephthalate or polytrimethylene terephthalate; cuprammonium regenerated rayon, viscose rayon, acetate rayon; natural fibers such as cotton, silk, wool, and linen.

[0057] The present invention will be described in more detail below with reference to the examples. The following examples are only for illustrating the present invention and are not intended to limit the protection scope of the present invention.

[0058] Examples

[0059] Example 1

[0060] PTMG was mixed with 4,4'-methylenebis(phenyl isocyanate) at a capping ratio (CR) of 1.5, ethylenediamine was used as the chain extender, and diethylamine was used as the chain terminator. The ratio of the chain extender to the chain terminator was 10:1, and dimethylacetamide was used as the solvent. That is, 468.6 g of 4,4'-methylenebis(phenyl isocyanate) and 1926.0 g of polytetramethylene ether glycol (molecular weight 1800) were stirred and reacted for 150 minutes under a nitrogen stream at 90 °C to prepare a polyurethane-urea having isocyanate groups at both ends.

[0061] After the prepolymer was cooled to room temperature, 3350.7 g of dimethylacetamide was added to obtain a polyurethane-urea prepolymer solution. Then, 33.6 g (0.56 mol) of ethylenediamine and 5.1 g of diethylamine were dissolved in 651 g of dimethylacetamide and added to the prepolymer solution at 10 °C or lower to obtain a polyurethane-urea solution.

[0062] Based on the solid content of the polymer, 0.2 wt% of trimethylolpropane (TMP), 0.5 wt% of 5,7-di-tert-butyl-3-(3,4-dimethylphenyl)-3H-benzofuran-2-one, 1 wt% of 1,1,1',1'-tetramethyl-4,4'-(methylenedi-p-phenylene)diallophanate, 1 wt% of poly(N,N-diethyl-2-aminoethyl methacrylate), and 0.1 wt% of titanium dioxide were added as additives, and they were mixed evenly to obtain a polyurethaneurea spinning dope.

[0063] The obtained spinning dope was dry-spun at a speed of 900 m / min (spinning temperature: 260 °C) to prepare 40 denier, 3 filament polyurethaneurea elastic yarns, and their physical properties were evaluated, as shown in Table 1.

[0064] Examples 2 - 6

[0065] Polyurethaneurea elastic yarns were prepared in the same manner as in Example 1, except that the addition amount of trimethylolpropane (TMP) and the capping ratio (molar ratio of diisocyanate to polyol) relative to the solid content of the final polyurethaneurea polymer were changed as shown in Table 1, and their physical properties were evaluated, as shown in Table 1.

[0066] Comparative Example 1

[0067] Polyurethaneurea elastic yarns were prepared in the same manner as in Example 1, except that trimethylolpropane (TMP) was not added, and their physical properties were evaluated, as shown in Table 1.

[0068] Comparative Examples 2 - 6

[0069] Polyurethaneurea elastic yarns were prepared in the same manner as in Example 1, except that the addition amount of trimethylolpropane (TMP) and the capping ratio (molar ratio of diisocyanate to polyol) relative to the solid content of the final polyurethaneurea polymer were changed as shown in Table 1, and their physical properties were evaluated, as shown in Table 1.

[0070] Test Examples

[0071] In the examples, the physical properties of the polyurethaneurea elastic yarns were measured as follows.

[0072] *Elongation rate of yarn

[0073] Using an automatic tensile strength measurement device (MEL device, Textechno), a 10 cm long sample was stretched at a tensile speed of 100 cm / min to measure the elongation at break value.

[0074] *Strength of yarn (5th unload at 200%)

[0075] Using an automatic tensile strength measuring device (MEL device, Textechno), a sample with a length of 10 cm × 20 strands was repeatedly stretched to 300% 5 times at a stretching speed of 100 cm / min, and the strength in the 200% range during 5 recoveries was measured.

[0076] *Elastic recovery rate of yarn (Immediate recovery)

[0077] Using an automatic tensile strength measuring device (MEL device, Textechno), a sample with a length of 10 cm × 20 strands was repeatedly stretched to 300% 5 times at a stretching speed of 100 cm / min, and the ratio (%) of the initial length to the deformed length was measured.

[0078] *Heat resistance of yarn

[0079] Using an automatic tensile strength measuring device, after repeatedly stretching 5 times between 0 and 300%, the stress (P1) at 200% during the fifth recovery and the stress (P2) at 200% during the fifth recovery after heat treatment were measured, and the heat resistance of the yarn was evaluated according to the following formula. The heat treatment of the yarn was to expose the yarn to air, stretch it to 100%, dry heat treat it at 190 °C for 1 minute, cool it to room temperature, and then, in the relaxed state, wet heat treat it at 100 °C for 30 minutes and dry it at room temperature.

[0080] Heat resistance (%) = P2 / P1 × 100

[0081] [Table 1]

[0082]

[0083] From the results in Table 1 above, it can be seen that when trimethylolpropane is applied to the polyurethane urea polymer, by adjusting the capping ratio within the range of 1.30 to 1.65 and applying trimethylolpropane, there will be no problems in the process application, and excellent elastic recovery rate and good elongation can be ensured. At the same time, the heat resistance is improved, so that the thermal brittleness of the textile using the elastic yarn of the present invention during the post-processing process can be improved.

Claims

1. A method for preparing a polyurethane urea elastic yarn, the polyurethane urea elastic yarn being composed of a polyol and a diisocyanate polymer, characterized in that, A prepolymer with a blocking ratio CR of 1.30 to 1.65 is prepared using a polyol and a diisocyanate. The addition amount of trimethylolpropane is 0.2 to 5.0 weight percent based on the weight of the polyurethaneurea yarn.

2. The preparation method of the polyurethane-urea elastic yarn according to claim 1, characterized in that, The method includes: A first polymerization step of mixing the polyol and the diisocyanate with a blocking ratio CR of 1.30 to 1.65 to form a prepolymer; After adding a solvent to the obtained prepolymer, contacting it with one or more chain extenders for a second polymerization to obtain a polyurethaneurea spinning dope; and A step of spinning the polyurethaneurea spinning dope to form a polyurethaneurea elastic yarn, In the method, trimethylolpropane is added in the first polymerization step, in the second polymerization step, or after the second polymerization step.

3. The preparation method of the polyurethane urea elastic yarn according to claim 1, characterized in that, By adding the trimethylolpropane, the viscosity increase rate after addition is within 100%.

4. The preparation method of the polyurethane urea elastic yarn according to claim 1, characterized in that, By adding the trimethylolpropane, the ratio of the hard segment to the soft segment is in the range of 4:96 to 10:90 by weight.

5. The preparation method of the polyurethane-urea elastic yarn according to claim 1, characterized in that, The diisocyanate is one or more selected from the following group: 4,4'-diphenylmethane diisocyanate, 1,5'-naphthalene diisocyanate, 1,4'-phenylene diisocyanate, 2,4'-diphenylmethane diisocyanate, hexamethylene diisocyanate, 1,4'-cyclohexane diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, or isophorone diisocyanate.

6. The preparation method of the polyurethane urea elastic yarn according to claim 1, characterized in that, The polyol is one or more selected from the following group: polytetramethylene ether glycol, polypropylene glycol, polyethylene glycol, polycarbonate diol, a copolymer of a mixture of an alkylene oxide and a lactone monomer and polytetramethylene ether glycol, and a copolymer of 3-methyl-tetrahydrofuran and tetrahydrofuran.

7. The preparation method of the polyurethane urea elastic yarn according to claim 1, characterized in that, The chain extender is one or more selected from the following group: ethylenediamine, 1,2-propanediamine, 1,3-propanediamine, 1,4-butanediamine, 2,3-butanediamine, 1,5-pentanediamine, 1,6-hexanediamine, and 1,4-cyclohexanediamine.

8. The method for preparing the polyurethane urea elastic yarn according to claim 1, characterized in that, The chain terminator is selected from the following group: diethylamine, monoethanolamine, cyclohexylamine, and dimethylamine. The organic solvent used in the preparation of the polymer solution is N,N'-dimethylformamide, N,N'-dimethylacetamide, or dimethyl sulfoxide.

9. The preparation method of the polyurethane urea elastic yarn according to claim 1, characterized in that, After further adding an additive to the spinning dope, spinning is carried out. The additive is one or more selected from the following: delustering agent, ultraviolet stabilizer, antioxidant, NOx gas yellowing inhibitor, anti-sticking agent, accelerating agent, and anti-chlorine agent.

10. A polyurethaneurea elastic yarn prepared by the method according to any one of claims 1 to 9, characterized in that, Based on the weight of the polyurethaneurea yarn, it contains 0.2 to 5.0 weight percent of trimethylolpropane.

11. The polyurethane-urea elastic yarn according to claim 10, wherein, In the polyurethaneurea elastic yarn, the elongation rate of the yarn is 450% or more, the heat resistance is 60% or more, and the elastic recovery rate is 26% or less.

12. The polyurethane-urea elastic yarn according to claim 10, wherein, The polyurethaneurea elastic yarn consists of: (a) Polytetramethylene ether glycol; (b) 4,4'-methylenebis(phenyl isocyanate); and (c) A polyurethaneurea reaction product of a mixture of chain extenders containing ethylenediamine and diethylamine, And, based on the weight of the polyurethaneurea yarn, it contains 0.2 to 5.0 weight percent of trimethylolpropane.

13. A fabric, characterized in that, It contains the polyurethaneurea elastic yarn according to claim 10.

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