Dyeable polyurethane urea elastic yarn and preparation method thereof

Abstract

The present invention relates to a dyeable polyurethane urea elastic yarn comprising a mixed polyol comprising a polytetramethylene ether glycol (PTMG) and a polyethylene glycol having a number average molecular weight of 4100-6000, and an organic diisocyanate, characterized in that: the polyethylene glycol is contained in an amount of 3-15 mol% relative to the total mixed polyol; the polyurethane urea elastic yarn can be dyed through reactive dye, and when a polyester fiber or cellulose fiber and polyurethane blended product is dyed, the heat resistance can be improved, and the elongation weakening caused by using excessive polyethylene glycol can be improved, so that the problem of thread breakage or hole breaking on a fabric can be solved.

Description

Technical Field

[0001] The present invention relates to a dyeable polyurethane urea elastic yarn and a preparation method thereof, and more particularly to a dyeable polyurethane urea elastic yarn and a preparation method thereof, which can be dyed with reactive dyes and has improved heat resistance, thereby being used together with a relative yarn requiring a polar high-temperature heat treatment, and improving the problem of polyurethane urea elastic yarn breakage on fabrics by improving elongation. Background Art

[0002] Polyurethane urea elastic yarn is widely used in stretchable clothing such as stockings, underwear, sportswear, sanitary products, and various industrial materials due to its excellent stretchability and recovery properties.

[0003] Generally, polyurethane urea is prepared by reacting a polyol with an excess of a diisocyanate compound to obtain a prepolymer. This prepolymer is reacted appropriately to form a spinning dope for polyurethane urea fibers, which is then spun to obtain elastic yarns.

[0004] Depending on the application, polyurethane urea elastic yarn can be used in combination with various other relative yarns such as cotton, acrylic, wool, silk, etc. In particular, in the case of sportswear or underwear, it is often blended with cellulosic fibers such as cotton.

[0005] Polyurethane urea elastic yarn is hydrophobic and lacks dyeing sites in its molecular structure, making it difficult to dye. To improve the dyeability of polyurethane urea elastic yarn, Korean Patent No. 10-0580326 discloses a method for preparing polyurethane urea elastic yarn by adding a diester compound comprising a triazine compound and a tertiary amine to a polymer solution to produce polyurethane urea elastic fibers with excellent dyeability and lightfastness. Korean Patent Publication No. 2015-0074111 discloses dyeable thermoplastic polyurethane fibers prepared from a composition comprising a polyurethane, wherein the polyurethane comprises a reaction product of a polyol, one or more diisocyanates, one or more chain extenders, and a functional modifier that is a reaction product of an aminodiol and a Brönsted acid. While this technology is used to improve the dyeability of spandex, it is difficult to expect improved dyeability of polyurethane urea elastic yarn with reactive dyes.

[0006] As mentioned above, there are technologies that have previously been developed to improve the dyeability of spandex with acid dyes, but there are no technologies that can dye it with reactive dyes. Currently, there is no commercial production of spandex dyed with reactive dyes. Improving the dyeability of polyurethane urea-based elastic yarns with reactive dyes has remained a problem for decades, and it is widely believed that polyurethane fibers cannot be adequately dyed with reactive dyes. Currently, there is an urgent need to develop polyurethane urea elastic yarn products that can be dyed with reactive dyes. In particular, there is a pressing need to develop technologies that can improve the properties of the polyurethane polymer itself, rather than through coating or blending.

[0007] On the other hand, when using polyethylene glycol-based polyurethane urea elastic yarns, blended yarns of polyester and cellulose fibers require high-temperature salting on both sides. During this process, insufficient heat resistance reduces the fabric's strength, making it difficult to use. Furthermore, when using polyethylene glycol-based polyurethane urea elastic yarns, setting the end-capping ratio to 1.8 or higher to prevent a decrease in heat resistance reduces elongation. Even if the fabric is stretched in downstream processes, the heat setting process can cause breakage and micropores in the fabric, leading to more serious problems than anticipated. Summary of the Invention

[0008] Technical issues

[0009] The present invention aims to solve the problems of the prior art described above. An object of the present invention is to provide a dyeable polyurethane urea elastic yarn and a method for preparing the same, which improves the dyeability of polyurethane with reactive dyes, which is a problem in the dyeing process of blended products of polyurethane and other materials, while also exhibiting excellent heat resistance and high elongation.

[0010] Another object of the present invention is to provide a dyeable polyurethane urea elastic yarn and a method for preparing the same, which can be dyed with reactive dyes and improve heat resistance by mixing an excess of polyethylene glycol with polytetramethylene ether glycol. The yarn can be used with polyester fibers and other fibers that require high-temperature heat treatment, thereby improving the problem of breakage or holes in the polyurethane urea elastic yarn on fabrics.

[0011] Technical Solution

[0012] The present inventors discovered that during the preparation of the polymer used to make polyurethane urea elastic yarn, an excess of polyethylene glycol, one of the two polyols, can be used to dye the yarn with reactive dyes. The use of high-molecular-weight polyethylene glycol can overcome the reduced heat resistance caused by excess polyethylene glycol, leading to the completion of the present invention. Polyurethane urea elastic yarn typically cannot be properly dyed with reactive dyes and tends to lose its inherent physical properties after exposure to high temperatures, such as in high-temperature dyeing processes. Therefore, this discovery has extremely important technical implications.

[0013] One embodiment of the present invention for solving the above-mentioned technical problems relates to a dyeable polyurethane urea elastic yarn, comprising a mixed polyol formed from polytetramethylene ether glycol (PTMG) and polyethylene glycol having a number average molecular weight of 4100 to 6000, and an organic diisocyanate, characterized in that the polyethylene glycol is contained in an amount of 3 to 15 mol percent relative to the total mixed polyol.

[0014] The present invention is characterized in that the heat resistance of the raw yarn, as determined by the following equation 1, is greater than 45%, based on the stress P1 measured before heat treatment at a stretch ratio of 200% and the stress P2 measured after heat treatment at a stretch ratio of 200%. In this case, the heat treatment conditions are as described in the Examples.

[0015] [Mathematical formula 1]

[0016] Heat resistance (%) = P2 / P1×100

[0017] In the present invention, the intrinsic viscosity (IV) of the polyurethane urea polymer constituting the polyurethane urea elastic yarn may be 1.1 to 1.2, and the amine terminal concentration of the polyurethane urea elastic yarn may be 3 to 20 meq / kg.

[0018] When the polyurethane urea elastic yarn of the present invention is dyed with a reactive dye, it can exhibit an L* value of 25 or less. The above-mentioned dyeability refers to the L* value obtained by measuring the reflectance of the yarn using a spectrophotometer and calculating the color difference using the CIE laboratory color difference calculation formula after dyeing the reactive dye, CI Reactive Black 31, in a 3% dye solution at 60°C for 60 minutes.

[0019] Another embodiment of the present invention relates to a method for preparing polyurethane urea elastic yarn, characterized in that after preparing a polyurethane prepolymer by polymerizing polytetramethylene ether glycol and polyethylene glycol having a number average molecular weight of greater than 4100 and less than 6000 with a diisocyanate compound, the prepolymer is dissolved in a solvent to prepare a prepolymer solution, the prepolymer solution is subjected to a chain extension reaction with an amine solution containing a diamine chain extender and an amine chain terminator to obtain a polyurethane urea spinning solution containing a polyurethane urea polymer, and the obtained polyurethane urea spinning solution is spun to prepare the polyurethane urea elastic yarn, wherein the polyethylene glycol is used in an amount of 3 mol% to 15 mol% relative to the total polyol.

[0020] The intrinsic viscosity (IV) of the polyurethane urea polymer is 1.1 to 1.2, and the concentration of the amine terminals of the polyurethane urea elastic yarn is 3 to 20 meq / kg.

[0021] Another embodiment of the present invention relates to a stretchable fabric, which comprises a mixture of the polyurethane urea elastic yarn and polyester fiber or cellulose fiber.

[0022] Effects of the Invention

[0023] The polyurethane urea elastic yarn of the present invention has the following advantages: when the prepolymer of the polyurethane urea elastic yarn is polymerized, 3 to 15 mol percent of polyethylene glycol (PEG) having a molecular weight of 4100 to 6000 g / mol is mixed with polytetramethylene ether glycol (PTMG) to improve hydrophilicity, ensure dyeability with reactive dyes, and improve heat resistance. The yarn can also be used as a fabric for a blend of PET (polyethylene terephthalate) and cellulose in T / C or T / R spinning.

[0024] Furthermore, in the present invention, the intrinsic viscosity (IV) of the polyurethane polymer is limited to 1.1 to 1.2 to improve the elongation, thereby solving the problem of breakage and holes in the polyurethane urea elastic yarn in the fabric in the downstream process.

[0025] Furthermore, according to the present invention, the intrinsic viscosity of the polymer and the number of amine terminals of the precursor can be reduced, thereby making the polymerization working conditions smoother than before, thereby improving the stability of the polymerization working. DETAILED DESCRIPTION

[0026] Hereinafter, the present invention will be described in more detail.

[0027] In this specification, the term "polyurethaneurea elastic yarn" refers to a synthetic fiber whose fiber-forming material is a long-chain synthetic polymer composed of at least 85 weight percent segmented polyurethane or polyurethaneurea. In the context of the present invention, the term "polyurethaneurea elastic yarn" and the term "spandex" can be used interchangeably.

[0028] "meq / kg" refers to the total ingredient, ie, milliequivalents of a specified ingredient per kilogram of polymer solids.

[0029] One embodiment of the present invention relates to a dyeable polyurethaneurea elastic yarn, which is a polyurethaneurea elastic yarn comprising a mixed polyol composed of polytetramethylene ether glycol (PTMG) and polyethylene glycol having a number average molecular weight of 4100 to 6000, and an organic diisocyanate, characterized in that the polyethylene glycol is contained in an amount of 3 to 15 mol percent relative to the total mixed polyol.

[0030] The present invention provides a polyurethane urea elastic yarn having excellent dyeability for reactive dyes, improved heat resistance, and improved productivity, and a preparation method thereof. When a polyurethane prepolymer is polymerized, the heat resistance is improved by increasing the molecular weight of polytetramethylene ether glycol (PTMG) to polyethylene glycol (PEG) with a molecular weight of 4100 to 6000 g / mol. Thus, the yarn can be used together with PET blended yarns requiring heat resistance, such as T / C or T / R spinning.

[0031] In order to improve the heat resistance of polyurethane urea elastic yarn, preferably, the molecular weight of polyethylene glycol (PEG) is 4100-6000. When the molecular weight of polyethylene glycol is less than 4100, the heat resistance and elongation of the raw yarn are reduced. When it is difficult to use relative yarns such as T / C or T / R that require heat resistance, the physical properties of the fabric are reduced during the heat fixation and salt processing process, making it difficult to use. When the molecular weight of polyethylene glycol (PEG) is greater than 6000, the melting point of polyethylene glycol (PEG) is higher than 60°C, which makes it difficult to use in the process. Since the viscosity of the prepolymer is high, the temperature of the prepolymer needs to be maintained above 60°C to ensure fluidity. In a high temperature environment, gel is formed due to side reactions, resulting in poor polymerization stability and spinning workability.

[0032] High heat resistance is a crucial characteristic of polyurethane urea elastic yarn when used as polyester fiber yarn or in blended fabrics with cotton. Heat resistance is particularly crucial during dyeing. Specifically, when used in fabrics blended with polyester fibers or dyed with neutral colors, the dyeing temperature tends to be higher. Furthermore, to achieve excellent stretchability, dimensional stability, and surface quality, dry heat treatment at high temperatures is commonly performed before dyeing. Therefore, elastic yarns require high heat resistance.

[0033] As shown in the present invention, when polyethylene glycol (PEG) with a molecular weight of 4100 to 6000 g / mol is used, heat dissipation is improved compared to when polyethylene glycol (PEG) with a molecular weight of 2000 to 4000 g / mol is used at the same content (molar percentage). When the molecular weight of polyethylene glycol (PEG) is 4100 to 6000, the PEG content is 3 to 15 molar percentage. If the polyethylene glycol (PEG) content is less than 3 molar percentage, the dyeability of reactive dyes is insufficient. If the PEG content is greater than 15 molar percentage, the heat resistance of the raw yarn will be reduced, making it difficult to use with relative yarns such as T / C or T / R spinning that require heat resistance.

[0034] For the elastic yarn of the present invention, the heat resistance of the yarn, determined by measuring the stress P1 in a stretched state at a stretch ratio of 200% before heat treatment and the stress P2 in a stretched state at a stretch ratio of 200% after heat treatment and using the following mathematical formula 1, is preferably greater than 45%.

[0035] [Mathematical formula 1]

[0036] Heat resistance (%) = P2 / P1×100

[0037] During the heat treatment process of the above-mentioned raw silk, the raw silk was stretched 100% while exposed to the atmosphere, dry-heat treated at 190°C for 1 minute and then cooled to room temperature, treated in a 0.9 g / L NaOH solution at 90°C for 30 minutes and washed with water three times, treated in a 0.4 g / L acetic acid solution at 130°C for 40 minutes and washed with water three times, and then dry-heat treated at 170°C for 1 minute and cooled to room temperature and then relaxed.

[0038] Furthermore, to improve elongation, the intrinsic viscosity (IV) of the polyurethaneurea polymer is maintained within the range of 1.1 to 1.2, and the number of amine terminals of the precursor is 3 to 20 meq / kg. If the intrinsic viscosity (IV) of the polyurethaneurea polymer is greater than 1.2, the polymer chain length increases, and entanglement between the chains increases. This entanglement hinders the stretching of the polyurethaneurea elastic precursor, thereby reducing elongation. If the intrinsic viscosity (IV) of the polyurethaneurea polymer is less than 1.1, the molecular weight of the polymer chain decreases, thereby reducing the heat resistance of the precursor. Therefore, to improve elongation and maintain heat resistance, the intrinsic viscosity (IV) of the polyurethaneurea polymer is preferably 1.1 to 1.2.

[0039] Furthermore, in the present invention, when the intrinsic viscosity (IV) of the polyurethaneurea polymer is maintained at 1.2 or less, the reactive dye can easily penetrate into the molecular structure, thereby improving the dyeability even when the number of precursor ends is less than 10. Therefore, after the precursor is produced, post-polymerization due to the ends that may occur during storage is suppressed, thereby preventing a decrease in elongation.

[0040] To improve elongation, the polyurethane urea elastic yarn of the present invention preferably has a yarn amine terminal count of 3 to 20 meq / kg. Amine terminals in the yarn serve as dyeing sites that can bind to dyes. If the yarn amine terminal count is less than 3 meq / kg, insufficient dyeing sites are present, and sufficient dyeability with reactive dyes cannot be expected. Furthermore, if the yarn amine terminal count exceeds 20 meq / kg, post-polymerization may reduce elongation during storage.

[0041] The polyurethane urea elastic yarn of the present invention is easily accessible to reactive dyes due to the use of an excess of polyethylene glycol. At the same time, the number of amine terminals is adjusted to ensure a sufficient amount of dyeing sites, thereby enriching the functional groups that can bind to reactive dyes, thereby demonstrating the dyeability of the polyurethane urea elastic yarn with reactive dyes.

[0042] Preferably, for the dyeable polyurethane urea elastic yarn of the present invention, when dyeing with CI Reactive Black 31 as a reactive dye at 60°C for 60 minutes in an owf 3% concentration, the reflectance of the raw yarn is measured using a spectrophotometer and calculated using the CIE laboratory color difference calculation formula. The L* value is less than 25, more preferably less than 22, and most preferably less than 20.

[0043] Another embodiment of the present invention relates to a method for producing dyeable polyurethaneurea elastic yarn. In this method, polytetramethylene ether glycol (PTMG) and polyethylene glycol with a number average molecular weight of 4100 to 6000 are polymerized with a diisocyanate compound to prepare a polyurethane prepolymer. This prepolymer is then dissolved in a solvent to prepare a prepolymer solution. Next, the prepolymer solution is subjected to a chain extension reaction with an amine solution containing a diamine chain extender and an amine chain terminator to obtain a polyurethaneurea spinning solution containing a polyurethaneurea polymer. This resulting polyurethaneurea spinning solution is then spun to produce the polyurethaneurea elastic yarn. In this case, the polyethylene glycol is used in an amount of 3 to 15 mol percent relative to the total polyol content.

[0044] In the present invention, preferably, 3.0 to 15.0 mol % of polyethylene glycol is mixed with respect to the total polyol. Using less than 3.0 mol % of polyethylene glycol makes dyeing with reactive dyes difficult, while using more than 15.0 mol % of polyethylene glycol results in poor spinning performance and reduced raw yarn properties due to reduced heat resistance, making it difficult to use in the process.

[0045] Specific examples of the organic diisocyanate used in preparing the polyurethane urea elastic yarn of the present invention include 4,4'-diphenylmethane diisocyanate, 1,5'-naphthalene diisocyanate, 1,4'-phenylene diisocyanate, hexamethylene diisocyanate, 1,4'-cyclohexane diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, and isophorone diisocyanate. One of these organic diisocyanates or a mixture of two or more thereof may be used, but the present invention is not limited thereto.

[0046] As a chain extender for extending the chain of the prepolymer, a diamine can be used. Examples of such a diamine chain extender include hydrazine, ethylenediamine, 1,2-propylenediamine, 1,3-propylenediamine, 1,2-butylenediamine (1,2-diaminobutane), 1,3-butylenediamine (1,3-diaminobutane), 1,4-butylenediamine (1,4-diaminobutane), 1,3-diamino-2,2-dimethylbutane, 4,4'-methylenebiscyclohexylamine, 1-amino-3,3,5-trimethyl-5-aminomethylcyclohexane, 1,6-hexanediamine, 2,2- Dimethyl-1,3-diaminopropane, 2,4-diamino-1-methylcyclohexane, N-methylaminobis(3-propylamine), 2-methyl-1,5-pentanediamine, 1,5-diaminopentane, 1,4-cyclohexanediamine, 1,3-diamino-4-methylcyclohexane, 1,3-cyclohexanediamine, 1,1-methylenebis(4,4'-diaminohexane), 3-aminomethyl-3,5,5-trimethylcyclohexane, 1,3-pentanediamine (1,3-diaminopentane), m-xylenediamine, and mixtures thereof, but are not limited thereto.

[0047] In the present invention, a chain terminator is generally used in the chain extension reaction to control the molecular weight of the polyurethane. Any chain terminator known in the technical field of the present invention can be used. Examples of chain terminators include, but are not limited to, diethylamine (DEA), cyclohexylamine, butylamine, hexanol, butanol, and mixtures of two or more thereof.

[0048] Examples of solvents that improve spinnability by adjusting the polymer solids concentration include diethylacetamide, dimethylformamide, hexamethylphosphonium amide, dimethylnitrosamine, dimethylpropionamide, methoxydimethylacetamide, N-methylpyrrolidine, dimethyl sulfoxide, and tetramethylene sulfone. Dimethylformamide and dimethylacetamide are advantageous in terms of compatibility with the polymer, spinnability, and solvent recovery. The amount of solvent used is preferably adjusted to maintain a polymer solids concentration of 15 to 45%. A concentration below 15% or exceeding 45% may adversely affect spinnability.

[0049] In the spinning and winding steps, the spinning solution is degassed, dry-spinned at a spinning temperature of 230° C. to 300° C., and then wound at a winding speed of 500 m / min to 1500 m / min.

[0050] Another embodiment of the present invention relates to a stretch fabric comprising a polyurethane urea elastic yarn mixed with polyester fiber or cellulose fiber. The polyurethane urea elastic yarn of the present invention can be used alone or in combination with other fibers or as a covering.

[0051] The polyurethane urea elastic yarn of the present invention can be woven together with nylon fiber, polyester fiber, cotton, rayon or other cellulose fiber as a counter yarn to prepare a fabric. In particular, when a blended yarn of polyester fiber and cotton or a blended yarn of polyester fiber and cellulose fiber, such as a blended yarn of polyester fiber and rayon, is used as the counter yarn to weave the fabric, the improved hydrophilicity of the polyurethane urea elastic yarn makes it easier for dyes to come into contact, thereby improving the dyeability with reactive dyes. By improving the heat resistance and elongation, the physical properties of the original yarn are maintained during the salt processing process, thereby preventing the physical properties of the fabric from being degraded or the original yarn from being broken.

[0052] Hereinafter, the present invention will be described in more detail with reference to examples. Such examples are merely provided to illustrate the practice of the present invention and are not intended to limit the present invention to these examples.

[0053] Example

[0054] Example 1

[0055] After mixing 90.1 kg of polytetramethylene ether glycol (PTMG) with 10 mol% polyethylene glycol (molecular weight 4300), 26.4 kg of 4,4'-diphenylmethane diisocyanate was added and stirred at 90°C for 120 minutes under a nitrogen flow to allow reaction to occur. This produced a polyurethane prepolymer containing isocyanates at both ends. After cooling the prepolymer to room temperature, 229 kg of dimethylacetamide was added as a solvent to obtain a polyurethane prepolymer solution. Subsequently, 3.2 kg of ethylenediamine (chain extender) and 0.4 kg of diethylamine (chain terminator) were dissolved in 50 kg of dimethylacetamide and added to the prepolymer solution at a temperature below 10°C to obtain a polyurethaneurea solution with an IV of 1.15. Additionally, 1.5 weight percent of triethylene glycol-bis-3-(3-tert-butyl-4-hydroxyphenyl) propionate as an antioxidant and 4 weight percent of hydrotalcite (Mg4Al2(OH) 12 A polyurethane urea spinning solution was prepared using CO₃·3H₂O) as an inorganic antichloride agent and 0.5 weight percent titanium dioxide as a light stabilizer. This solution was dry-spun at 900 m / min to produce polyurethane urea elastic yarn with a denier of 40 and an amine terminal count of 10 meq / kg.

[0056] Example 2

[0057] During the preparation of the prepolymer of Example 1, a polyurethane urea elastic yarn was prepared in the same manner as in Example 1 except that polyethylene glycol with a molecular weight of 5500 was used.

[0058] Example 3

[0059] During the preparation of the prepolymer of Example 1, polyurethane urea elastic yarn was prepared in the same manner as in Example 1 except that 5 mol % of polyethylene glycol was added.

[0060] Example 4

[0061] During the preparation of the prepolymer of Example 1, a polyurethane urea elastic yarn was prepared in the same manner as in Example 1 except that 5 mol % of polyethylene glycol having a molecular weight of 5500 was mixed.

[0062] Examples 5 to 8

[0063] Polyurethane urea elastic yarns were prepared in the same manner as in Examples 1 to 4 except that the intrinsic viscosity (IV) of the polyurethane polymer was changed as shown in Table 1 below.

[0064] Examples 9 to 14

[0065] Polyurethane urea elastic yarns were prepared in the same manner as in Example 1 except that polyethylene glycol with a molecular weight of 5500 was used and the polyethylene glycol content, the intrinsic viscosity of the polymer, and the number of amine terminals of the precursor yarn were changed as shown in Table 1 below.

[0066] Comparative Examples 1 to 4

[0067] During the preparation of the prepolymer, the same procedures as in Example 1 were followed, except that the molecular weight of the polyethylene glycol was changed as shown in Table 1 below, to prepare polyurethane urea elastic yarns.

[0068] Comparative Examples 5 to 8

[0069] Polyurethane urea elastic yarn was prepared in the same manner as in Example 1 except that the content of polyethylene glycol was changed as shown in Table 1 below.

[0070] Comparative Examples 9 to 16

[0071] Polyurethane urea elastic yarn was prepared in the same manner as in Example 1 except that polyethylene glycol with a molecular weight of 5500 was used and the polyethylene glycol content, the intrinsic viscosity of the polymer, and the number of amine terminals of the raw silk were changed as shown in Table 1 below.

[0072] Experimental example

[0073] The physical properties of the polyurethane urea elastic yarns prepared in Examples and Comparative Examples were evaluated by the following methods, and the results are shown in Table 1 below.

[0074] (1) Heat resistance (strength retention before and after heat treatment): The heat resistance of the raw yarn was calculated by repeating stretching and relaxation between 0% and 300% for 5 times using an automatic strength-elongation measuring device, and then calculating the stress value at 200% when relaxing after the fifth stretching. The stress value P1 of the raw yarn before heat treatment and the stress P2 after heat treatment were measured, and the heat resistance of the raw yarn was evaluated according to the following mathematical formula 1. In this case, during the heat treatment of the raw yarn, the raw yarn was stretched 100% while exposed to the atmosphere, dry-heated at 190°C for 1 minute and cooled to room temperature, then treated in a 0.9 g / L NaOH solution at 90°C for 30 minutes and washed with water 3 times, treated in a 0.4 g / L acetic acid solution at 130°C for 40 minutes and washed with water 3 times, and then dry-heated at 170°C for 1 minute, cooled to room temperature, and then relaxed.

[0075] [Mathematical formula 1]

[0076] Heat resistance (%) = P2 / P1×100

[0077] (2) L* value: The L* value, which indicates the degree of dyeing, is calculated using the CIE laboratory color difference formula after measuring the reflectance of the raw yarn using a spectrophotometer. The L* value represents brightness. When dyed with the same dye, the darker the color, the smaller the L* value.

[0078] Staining method:

[0079] CI Reactive Black 31 was used as a reactive dye with an OF of 3% and a bath ratio of 1:20. The dye and sample were added to a dye bath prepared with 60 g / L of Na₂SO₄. The temperature was then raised to 60°C at a rate of 2°C / min. Once the temperature reached 60°C, 20 g / L of Na₂CO₃ was added and the bath maintained for 60 minutes. After cooling to room temperature, the bath was repeatedly rinsed with water and drained until no color remained in the drainage.

[0080] (3) Polymer Storage Stability: After sampling the prepared urethane urea solution into a glass bottle without generating bubbles, the turbidity is measured using a turbidity colorimeter. If the turbidity is 0.4 or higher, the polymer viscosity degradation rate per hour is 200 P / hr or higher, and the polymer storage stability is judged to be poor.

[0081] (4) Spinning workability: When the full bobbin rate (%) calculated by the following mathematical formula 2 during the spinning operation is less than 90%, the spinning workability is judged to be poor.

[0082] [Mathematical formula 2]

[0083] Full pipe rate (%) = (full pipe production / total production) × 100

[0084] [Table 1]

[0085]

[0086]

[0087] Referring to the results in Table 1 above, in the case of Comparative Examples 1 and 2, the PEG molecular weight is less than 4100, resulting in low heat resistance and difficulty in using with PET blended yarns such as T / C or T / R spinning that require heat resistance. In the case of Comparative Examples 3 and 4, the PEG molecular weight is greater than 6000, and the melting point of PEG is relatively high at above 60°C, resulting in poor impedance stability and spinning operability, making it difficult to apply to the process.

[0088] In the case of Comparative Examples 5 and 6, the PEG content is less than 3 mol percent, resulting in poor dyeability. In the case of Comparative Examples 7 and 8, the PEG content is greater than 15 mol percent, resulting in reduced heat resistance, making it difficult to use with PET blended yarns that require heat resistance, such as T / C or T / R spinning.

[0089] In Comparative Examples 9 to 10, the inherent viscosity (IV) of the polyurethane urea polymer is less than 1.1, and the polymer chain length is short, resulting in reduced heat resistance and poor spinning workability, making it difficult to apply to the process. In Comparative Examples 11 to 12, the polyurethane urea polymer has an IV greater than 1.2. Due to the increase in polymer chain length, entanglement between chains will increase, and the elongation of the raw yarn will decrease. As a result, it will be difficult to use due to holes in the fabric.

[0090] In Comparative Examples 13 to 14, the amine terminal concentration was less than 3 meq / kg, and the dyeing sites in the raw yarn were insufficient, so the dyeability was negligible. In Comparative Examples 15 to 16, the amine terminal concentration was 15 meq / kg or more, and during the storage of the raw yarn, the elongation decreased due to post-polymerization, and thus, it was difficult to use due to holes in the fabric.

[0091] The present invention described above is not limited to the above embodiments. A person skilled in the art can make various substitutions, modifications and changes without departing from the technical scope of the present invention.

Claims

1. A dyeable polyurethane urea elastic yarn comprising a mixed polyol consisting of polytetramethylene ether glycol and polyethylene glycol having a number average molecular weight of not less than 4100 and not more than 6000, and an organic diisocyanate, wherein: The polyethylene glycol is contained in an amount of 3 to 15 mol % relative to the entire mixed polyol.

2. The dyeable polyurethane urea elastic yarn according to claim 1, characterized in that: The stress of the elastic yarn at a stretch rate of 200% was measured before heat treatment (P1) and after heat treatment (P2). The heat resistance of the original yarn obtained by the following mathematical formula (1) was greater than 45%. [Mathematical formula 1] Heat resistance (%) = P2 / P1×100.

3. The dyeable polyurethane urea elastic yarn according to claim 1, characterized in that: The polyurethane urea polymer constituting the polyurethane urea elastic yarn has an intrinsic viscosity IV of 1.1 to 1.

2.

4. The dyeable polyurethane urea elastic yarn according to claim 1, characterized in that: The concentration of the amine terminal of the polyurethane urea elastic yarn is 3 to 20 meq / kg.

5. The dyeable polyurethane urea elastic yarn according to claim 1, characterized in that: When the polyurethane urea elastic yarn is dyed with a reactive dye, the L* value exhibits dyeability of 30 or less.

6. A method for preparing dyeable polyurethane urea elastic yarn, characterized in that: After preparing a polyurethane prepolymer by polymerizing polytetramethylene ether glycol and polyethylene glycol having a number average molecular weight of not less than 4100 and not more than 6000 with a diisocyanate compound, the prepolymer is dissolved in a solvent to prepare a prepolymer solution. The prepolymer solution is subjected to a chain extension reaction with an amine solution containing a diamine chain extender and an amine chain terminator to obtain a polyurethane urea spinning solution containing a polyurethane urea polymer. The obtained polyurethane urea spinning solution is spun to prepare a polyurethane urea elastic yarn, wherein the polyethylene glycol is used in an amount of 3 mol % to 15 mol % relative to the total polyol.

7. The method for preparing dyeable polyurethane urea elastic yarn according to claim 6, characterized in that: The intrinsic viscosity IV of the polyurethane urea polymer is 1.1 to 1.2, and the concentration of the amine terminals of the polyurethane urea elastic yarn is 3 to 20 meq / kg.

8. A stretchable fabric, characterized in that: The dyeable polyurethane urea elastic yarn according to any one of claims 1 to 5 is mixed with other fibers.

9. The stretch fabric according to claim 8, wherein: The other fibers are polyester fibers or cellulose fibers or blended yarns of polyester fibers and cellulose fibers.

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