Polyurethane elastic fiber for use in fabrics that can be cut arbitrarily, its manufacturing method and use

Abstract

This invention provides polyurethane elastic fibers for use in a face material that can be cut at will, a method for manufacturing the same, and a method for using the same. [Solution] The raw materials used in the production of the polyurethane elastic fiber include isocyanate, modified polyol, bifunctional compound, and composite additive. The polyurethane elastic fiber for arbitrary cutting produced by the present invention has excellent mechanical performance, with a strength of 2.01 to 2.18 d / g, a constant tensile stress of 13.0 to 13.7 cN, and a breaking elongation of 522 to 557%. High-efficiency heat setting can be achieved at 175°C or below, with a heat setting efficiency of 87 to 92%. Furthermore, the fiber of the present invention has good heat resistance stability, with a decrease in strength of only about 2% after heat treatment, and a decrease in breaking elongation of no more than 10%. In addition, the polyurethane elastic fiber obtained by the present invention has excellent adaptability, and even when blended with fibers with poor heat resistance such as cotton, silk, and wool, the material exhibits good dimensional stability during cutting, with no curling or thread pulling at the edges, and can be cut arbitrarily.

Description

Technical Field

[0001] The present invention belongs to the technical field of fibers, and particularly relates to a polyurethane elastic fiber used for arbitrarily cuttable fabric, a method for producing the same and use thereof.

Background Art

[0002] Conventional fiber clothing design has mainly attached importance to applicability and convenience. However, with the continuous improvement and upgrading of consumers' living quality and consumption concepts, textile products at the present stage have characteristics such as health, comfort, aesthetics, fashionability and functionality.

[0003] "Free-cut" fabric is an emerging fabric in recent years, which is usually an elastic woven fabric formed by adding spandex to chemical fibers. Due to its good cutting adaptability and edge stability, it can be cut freely and is less prone to edge curling. Therefore, it has broad application prospects in the development field of emerging fabrics.

[0004] At present, heat setting processing is generally used to achieve dimensional stability of fabrics during cutting to a certain extent. Conventional polyurethane elastic fibers require a relatively high temperature during heat setting. However, when spandex is blended with fibers with low heat resistance such as cotton, silk and wool, setting at the conventional temperature of 190 to 195°C will significantly damage the dimensional and performance stability of cotton, silk, wool and the like. Therefore, fabrics produced using these materials are prone to insufficient strength, edge curling and thread slipping during cutting, which greatly impairs processability.

[0005] On the other hand, when the setting temperature is lowered to protect the structure of cotton, silk and wool, the internal stress cannot be completely eliminated, and the heat setting efficiency (HSE) thereof is significantly reduced.

[0006] Therefore, in order to obtain a high-performance fabric that is dimensionally stable, offers high cutting flexibility, and is resistant to curling, it is necessary to strictly control the heat setting temperature, and furthermore, the temperature must be adjusted appropriately depending on the type of fiber being blended with spandex. This leads to waste of raw materials, time, and labor.

[0007] On the other hand, the strength of "Zuishinsai" fabric is also relatively low, which limits its practical application in the textile field.

[0008] Therefore, there is a need to develop polyurethane elastic fibers that have high thermal setting efficiency at low temperatures and excellent strength. Fabrics spun using such fibers will have excellent cutting adaptability and edge stability, and have a wide range of application prospects in the textile field. [Overview of the project] [Problems that the invention aims to solve]

[0009] To solve problems existing in the technology, the present invention provides polyurethane elastic fibers for use in arbitrarily cuttable faceting materials, a method for manufacturing the same, and a method for using the same, thereby achieving the objectives of the invention, which is that the woven fabric has good dimensional stability, high strength, is resistant to curling, does not shed threads, and can be arbitrarily cut. [Means for solving the problem]

[0010] To solve the above technical problems, the present invention employs the following technical solution.

[0011] The first part of the present invention provides polyurethane elastic fibers for use in arbitrarily cut faceting materials, the raw materials used in the production of the polyurethane elastic fibers comprising isocyanates, modified polyols, bifunctional compounds, and compound additives.

[0012] Preferably, the molar ratio of the isocyanate to the modified polyol is 1.8 to 2:1.

[0013] Preferably, the isocyanate is one or more of the symmetrical isocyanates and asymmetrical isocyanates.

[0014] Furthermore, the symmetrical isocyanate is selected from one or more of the following: 4,4'-diphenylmethane diisocyanate, 2,2'-bis(4-isobutylisoamyl)propane, and 3,5'-diethyl-4-isobutylisoamylmethane.

[0015] Furthermore, the asymmetrical isocyanate is selected from one or more of the following: 2,4-diphenylmethane diisocyanate, isophorone diisocyanate, and 1,4-phenylenediisocyanate.

[0016] More preferably, the isocyanate consists of 2,2'-bis(4-isobutylisoamyl)propane and 2,4-diphenylmethane diisocyanate, with a molar ratio of 3:7.

[0017] Preferably, the method for producing the modified polyol is as follows.

[0018] S11 (activation) Diglycerin is added to chloroform, then triethylamine and toluenesulfonyl chloride are added, and the reaction is carried out at 0-5°C for 12-16 hours to replace one of the terminal hydroxyl groups of diglycerin with a tosylate group. After the reaction is complete, 1 mol / L aqueous hydrochloric acid is added to the reaction mixture and extracted to obtain the organic phase. Excess anhydrous sodium carbonate is added to the organic phase, and after thorough stirring, the mixture is filtered. The filtrate is added to excess anhydrous diethyl ether and stirred thoroughly to precipitate a white precipitate, which is then filtered by suction and dried to obtain activated diglycerin.

[0019] S12 (Modification of silane) Add activated diglycerin to DMSO, further add potassium trimethylsilanolate, and perform nucleophilic substitution reaction at room temperature for 8 to 10 hours. After completion of the reaction, centrifuge to collect the supernatant, and concentrate under reduced pressure to obtain a crude product. The crude product is extracted, dried over anhydrous sodium sulfate, to obtain a diglycerin-silane product.

[0020] S13 (Modification of pyridine) Add the diglycerin-silane product to DMSO, further add 2-pyridyl dithiocarbonate and potassium carbonate, allow the reaction to proceed at 40 to 50°C for 6 to 8 hours, and graft a pyridyl group onto the other terminal hydroxy group of the diglycerin-silane product. After completion of the reaction, centrifuge to collect the supernatant, and concentrate under reduced pressure to obtain a crude product. The crude product is extracted, dried over anhydrous sodium sulfate, and distilled under reduced pressure to obtain a modified polyol containing silane groups and pyridyl groups.

[0021] Preferably, the molar ratio of diglycerin to p-toluenesulfonyl chloride in step S11 is 1:2 to 2.4.

[0022] Preferably, in step S11, triethylamine serves as a basic catalyst, and the addition amount thereof is 1 to 2% by mass of diglycerin.

[0023] Preferably, the addition amount of potassium trimethylsilanolate in step S12 is 20 to 30% by mass of the activated diglycerin.

[0024] Preferably, the addition amount of 2-pyridyl dithiocarbonate in step S13 is 23 to 28% by mass of the diglycerin-silane product.

[0025] Preferably, the addition amount of potassium carbonate in step S13 is an amount sufficient to adjust the pH of the reaction system to 8 to 9.

[0026] The distribution ratio of hard / soft segments in spandex directly affects its setting temperature. The present applicant unexpectedly found that when 2,2'-bis(4-isobutylisoamyl)propane and 2,4-diphenylmethane diisocyanate in a molar ratio of 3:7 are used in combination with a modified polyol, spandex molecules have a specific hard / soft segment distribution ratio. That is, (1) 2,2'-bis(4-isobutylisoamyl)propane and 2,4-diphenylmethane diisocyanate introduce a certain proportion of rigid structure into the molecular structure of spandex, ensure the constant elongation stress and heat resistance of spandex, and at the same time utilize the steric hindrance effect to reduce the crystallinity of hard segments in the molecular structure, alleviate the constraint effect of hard segments on the soft segment molecular chains, and improve the heat setting efficiency of spandex to a certain extent; (2) diglycerin contains four hydroxy groups, after modification, a silane group is grafted to one terminal hydroxy group, and a pyridyl group is grafted to the other terminal hydroxy group. The modified polyol acts as a soft segment of spandex molecular chains, wherein the nitrogen atom on the pyridine ring has high electronegativity and low electron cloud density, which reduces the interaction force between pyridine molecules and molecular chains, thereby reducing the crystallinity of molecules, comprehensively improving the heat setting efficiency of spandex, and improving the dimensional stability of fabrics during the cutting process.

[0027] Preferably, the difunctional compound is one or more of 2-methyl-1,5-pentanediamine, 1,4-cyclohexanediol, neopentyl glycol, diethanolamine, and 3,5-bis(methylthio)toluenediamine.

[0028] More preferably, the difunctional compound is 2-methyl-1,5-pentanediamine, and the molar fraction thereof is 40 to 50% based on the total amount of isocyanate and modified polyol.

[0029] The higher the hard segment crystallinity of the spandex molecule, the more heat is required for the melting and recrystallization process of the crystalline region, resulting in insufficient setting at low temperatures. The hard segment structure formed by the reaction of 2-methyl-1,5-pentanediamine with 2,2'-bis(4-isobutylisoamyl)propane and 2,4-diphenylmethane diisocyanate in a molar ratio of 3:7 in this solution has reduced intermolecular chain interaction forces and is less likely to form a complex hydrogen bond network structure. As a result, the hard segment has low crystallinity, enabling highly efficient thermal setting even under low temperature conditions. Consequently, even when blended with heat-resistant fibers such as cotton, silk, and wool, the resulting fabric exhibits good dimensional stability, does not curl up, does not experience thread shedding, and can be cut arbitrarily.

[0030] Preferably, the composite additive is one or more of sodium benzoate, nano silicon dioxide (nanoSiO2), and nano calcium carbonate (nanoCaCO3), and the amount of the composite additive added is 1 to 1.5% of the total mass of the spandex raw material.

[0031] Preferably, the composite additive is nanosilicon dioxide and nanocalcium carbonate in a mass ratio of 3:1.5, and the particle size of the nanosilicon dioxide and nanocalcium carbonate is 50 to 100 nm.

[0032] The applicant has found that when the above-mentioned isocyanate and 2-methyl-1,5-pentanediamine are used, the set temperature can be reduced by decreasing the crystallinity of the hard segments in the spandex molecular chain, but this decrease in crystallinity leads to a decrease in the strength of the spandex. Since a silane group is bonded to one end of the modified polyol, in the present invention, when predetermined amounts of nanosilicon dioxide and nanocalcium carbonate in a mass ratio of 3:1.5 are added, the hydroxyl groups present on the surface of these nanoparticles react with the silane groups on the surface of the modified polyol to form crosslinking points, thereby improving the strength and thermal stability of the spandex to some extent and providing the fabric with excellent cutting adaptability and edge stability.

[0033] The second part of the present invention provides a method for producing polyurethane elastic fibers for use in a face material that can be arbitrarily cut.

[0034] S21: After dehydrating the modified polyol under reduced pressure at 115-125°C for 2-3 hours, add the compound additive and stir uniformly. When the temperature drops to 80-85°C, add the isocyanate and stir thoroughly. Then add the dibutyltin dilaurate and react for 2-3 hours, then cool for 60-80 minutes to obtain the prepolymer.

[0035] The S22:S21 prepolymer is dissolved in DMF to make a 20% solution. A bifunctional compound is added, and the mixture is reacted at 30-35°C for 2-3 hours. After maturation, filtration, and defoaming, a spinning solution with a viscosity of 3000-4000 poise (40°C) is obtained.

[0036] S23: The spinning solution from S22 is measured using a metering pump and extruded from the spinneret into the spinning duct. Upon heating, the solvent evaporates and solidifies to form a tow (bundle of yarn). This is then stretched, lubricated, and heat-set to obtain the polyurethane elastic fiber.

[0037] Preferably, the amount of dibutyltin dilaurate added in S21 is 0.08 to 0.12% of the total mass of the raw materials.

[0038] Preferably, the maturation temperature in S22 is 50-70°C and the maturation time is 12-24 hours.

[0039] Preferably, the temperature of the spinning duct in S23 is 230-270°C and the speed is 700-800 m / min.

[0040] Preferably, the stretch ratio in S23 is 2 to 3 times.

[0041] Preferably, the temperature of the heat set in S23 is 170-175°C and the time is 40-50 s.

[0042] A third part of the present invention provides the use of polyurethane elastic fibers for use in arbitrarily cuttable faceting, the use of which is applicable to the clothing field, particularly underwear and loungewear. [Effects of the Invention]

[0043] By adopting the above technical solution, the technical effects achieved by this invention are as follows:

[0044] The arbitrarily cut polyurethane elastic fiber for faceting manufactured according to the present invention has excellent mechanical properties, with a strength of 2.01 to 2.18 d / g, a constant tensile stress of 13.0 to 13.7 cN, a breaking elongation of 522 to 557%, and a heat setting efficiency of 87 to 92%.

[0045] The spandex obtained by this invention can achieve highly efficient heat setting at temperatures below 175°C. On the one hand, it optimizes the elasticity of the fabric, making it more durable and stable, less prone to deformation even after multiple stretches, and meeting the individualized needs of "custom cutting." On the other hand, it enhances the dimensional stability of the fabric, preventing deformation due to the release of internal stress in the spandex after cutting, and ensuring that the shape after cutting is as intended. Furthermore, it has excellent compatibility, and even when blended with fibers that have poor heat resistance, such as cotton, silk, and wool, the fabric produced with these fibers has good dimensional stability when cut, does not curl up, does not shed threads, and can be cut arbitrarily.

[0046] The spandex obtained by this invention has good heat resistance and stability, with a strength reduction of only about 2% after heat treatment and a reduction in elongation at break of no more than 10%. [Modes for carrying out the invention]

[0047] The present invention will be further described below based on specific examples. [Examples]

[0048] This is a polyurethane elastic fiber used for a faceting material that can be arbitrarily cut, and the raw materials used in the manufacture of this polyurethane elastic fiber include isocyanate, modified polyol, bifunctional compound, and composite additive.

[0049] The molar ratio of the isocyanate to the modified polyol is 1.9:1.

[0050] The isocyanates are 2,2'-bis(4-isobutylisoamyl)propane and 2,4-diphenylmethane diisocyanate in a molar ratio of 3:7.

[0051] The method for producing the modified polyol is as follows.

[0052] S11 (activation) Diglycerin is added to chloroform, then triethylamine and toluenesulfonyl chloride are added, and the reaction is carried out at 3°C ​​for 14 hours to replace one of the terminal hydroxyl groups of diglycerin with a toluenesulfonate group. After the reaction is complete, 1 mol / L aqueous hydrochloric acid is added to the reaction mixture and extracted to obtain the organic phase. Excess anhydrous sodium carbonate is added to the organic phase, and after thorough stirring, the mixture is filtered. The filtrate is added to excess anhydrous diethyl ether and stirred thoroughly to precipitate a white precipitate, which is then filtered by suction and dried to obtain activated diglycerin.

[0053] S12 (Modification of silane) Activated diglycerin is added to DMSO, followed by potassium trimethylsilanolate, and a nucleophilic substitution reaction is carried out at room temperature for 9 hours. After the reaction is complete, the supernatant is collected by centrifugation and concentrated under reduced pressure to obtain the crude product. The crude product is extracted and dried over anhydrous sodium sulfate to obtain the diglycerin-silane product.

[0054] S13 (Pyridine modification) The diglycerin-silane product is added to DMSO, and then 2-pyridyldithiocarbonate and potassium carbonate are added. The reaction is carried out at 45°C for 7 hours to graft a pyridyl group onto the other terminal hydroxyl group of the diglycerin-silane product. After the reaction is complete, the supernatant is collected by centrifugation and concentrated under reduced pressure to obtain the crude product. The crude product is extracted, dried over anhydrous sodium sulfate, and distilled under reduced pressure to obtain a modified polyol containing silane and pyridyl groups.

[0055] The molar ratio of diglycerin to toluenesulfonyl chloride in S11 is 1:2.2.

[0056] In S11, triethylamine is a basic catalyst, and its amount added is 1.5% of the mass of diglycerin.

[0057] The amount of potassium trimethylsilanolate added in S12 is 25% of the activated diglycerin mass.

[0058] The amount of 2-pyridyldithiocarbonate added in S13 is 26% of the mass of the diglycerin-silane product.

[0059] The amount of potassium carbonate added in step S13 is the amount necessary to adjust the pH of the reaction system to 8.5.

[0060] The aforementioned bifunctional compound is 2-methyl-1,5-pentanediamine, and its mole fraction is 45% of the total amount of isocyanate and modified polyol.

[0061] The composite additive consists of nanosilicon dioxide and nanocalcium carbonate in a mass ratio of 3:1.5, with a particle size of 50 nm for the nanosilicon dioxide and nanocalcium carbonate.

[0062] The amount of the aforementioned compound additive added is 1.2% of the total mass of the spandex raw material.

[0063] A method for producing polyurethane elastic fibers for use in arbitrarily cuttable faceting, provided in the second part of the present invention, is as follows:

[0064] S21: After dehydrating the modified polyol under reduced pressure at 120°C for 2 hours, the compound additive is added and stirred uniformly. When the temperature drops to 80°C, the isocyanate is added and stirred thoroughly. Then dibutyltin dilaurate is added and the mixture is reacted for 2.5 hours, after which it is cooled for 70 minutes to obtain the prepolymer.

[0065] The S22:S21 prepolymer is dissolved in DMF to make a 20% solution. A bifunctional compound is added, and the mixture is reacted at 32°C for 2.5 hours. After maturation, filtration, and defoaming, a spinning solution with a viscosity of 3600 poise (40°C) is obtained.

[0066] S23: The spinning solution from S22 is measured using a metering pump and extruded from the spinneret into the spinning duct. Upon heating, the solvent evaporates and solidifies to form a tow (bundle of yarn). This is then stretched, lubricated, and heat-set to obtain the polyurethane elastic fiber.

[0067] The amount of dibutyltin dilaurate added in S21 is 0.1% of the total mass of the raw materials.

[0068] The maturation temperature in S22 is 60°C and the maturation time is 20 hours.

[0069] In step S23, the temperature of the spinning duct is 250°C and the speed is 750 m / min.

[0070] The stretch ratio in S23 is 2.5 times.

[0071] In step S23, the temperature of the heat set is 170°C and the time is 50 seconds. [Examples]

[0072] This is a polyurethane elastic fiber used for a faceting material that can be arbitrarily cut, and the raw materials used in the manufacture of this polyurethane elastic fiber include isocyanate, modified polyol, bifunctional compound, and composite additive.

[0073] The molar ratio of the isocyanate to the modified polyol is 2:1.

[0074] The isocyanates are 2,2'-bis(4-isobutylisoamyl)propane and 2,4-diphenylmethane diisocyanate in a molar ratio of 3:7.

[0075] The method for producing the modified polyol is as follows:

[0076] S11 (activation) Diglycerin is added to chloroform, then triethylamine and toluenesulfonyl chloride are added, and the reaction is carried out at 0°C for 12 hours to replace one of the terminal hydroxyl groups of diglycerin with a toluenesulfonate group. After the reaction is complete, 1 mol / L aqueous hydrochloric acid is added to the reaction mixture and extracted to obtain the organic phase. Excess anhydrous sodium carbonate is added to the organic phase, and after thorough stirring, the mixture is filtered. The filtrate is added to excess anhydrous diethyl ether and stirred thoroughly to precipitate a white precipitate, which is then filtered by suction and dried to obtain activated diglycerin.

[0077] S12 (Modification of silane) Activated diglycerin is added to DMSO, followed by potassium trimethylsilanolate, and a nucleophilic substitution reaction is carried out at room temperature for 8 hours. After the reaction is complete, the supernatant is collected by centrifugation and concentrated under reduced pressure to obtain the crude product. The crude product is extracted and dried over anhydrous sodium sulfate to obtain the diglycerin-silane product.

[0078] S13 (Pyridine modification) The diglycerin-silane product is added to DMSO, and then 2-pyridyldithiocarbonate and potassium carbonate are added. The reaction is carried out at 40°C for 6 hours to graft a pyridyl group onto the other terminal hydroxyl group of the diglycerin-silane product. After the reaction is complete, the supernatant is collected by centrifugation and concentrated under reduced pressure to obtain the crude product. The crude product is extracted, dried over anhydrous sodium sulfate, and distilled under reduced pressure to obtain a modified polyol containing silane and pyridyl groups.

[0079] In S11, the molar ratio of diglycerin to toluenesulfonyl chloride is 1:2.

[0080] In S11, triethylamine is a basic catalyst, and its amount added is 1% of the mass of diglycerin.

[0081] The amount of trimethylsilanolate potassium added in S12 is 20% of the activated diglycerin mass.

[0082] The amount of 2-pyridyldithiocarbonate added in S13 is 23% of the mass of the diglycerin-silane product.

[0083] The amount of potassium carbonate added in step S13 is the amount necessary to adjust the pH of the reaction system to 8.

[0084] The aforementioned bifunctional compound is 2-methyl-1,5-pentanediamine, and its mole fraction is 40% of the total amount of isocyanate and modified polyol.

[0085] The composite additive consists of nanosilicon dioxide and nanocalcium carbonate in a mass ratio of 3:1.5, with a particle size of 100 nm for the nanosilicon dioxide and nanocalcium carbonate.

[0086] The amount of the aforementioned compound additive added is 1% of the total mass of the spandex raw material.

[0087] The method for producing polyurethane elastic fibers used in the arbitrarily cut face material is as follows.

[0088] S21: After dehydrating the modified polyol under reduced pressure at 115°C for 3 hours, the compound additive is added and stirred uniformly. When the temperature drops to 85°C, the isocyanate is added and stirred thoroughly. Then dibutyltin dilaurate is added and the reaction is allowed to proceed for 2 hours, followed by cooling for 60 minutes to obtain the prepolymer.

[0089] The S22:S21 prepolymer is dissolved in DMF to make a 20% solution. A bifunctional compound is added, and the mixture is reacted at 30°C for 3 hours. After maturation, filtration, and defoaming, a spinning solution with a viscosity of 3000 poise (40°C) is obtained.

[0090] S23: The spinning solution from S22 is measured using a metering pump and extruded from the spinneret into the spinning duct. Upon heating, the solvent evaporates and solidifies to form a tow (bundle of yarn). This is then stretched, lubricated, and heat-set to obtain the polyurethane elastic fiber.

[0091] The amount of dibutyltin dilaurate added in S21 is 0.08% of the total mass of the raw materials.

[0092] In step S22, the maturation temperature was 50°C and the maturation time was 12 hours.

[0093] In step S23, the temperature of the spinning duct is 230°C and the speed is 700 m / min.

[0094] The stretch ratio in S23 is 3 times.

[0095] In step S23, the temperature of the heat set was 170°C and the time was 40 seconds. [Examples]

[0096] This is a polyurethane elastic fiber used for a faceting material that can be arbitrarily cut, and the raw materials used in the manufacture of this polyurethane elastic fiber include isocyanate, modified polyol, bifunctional compound, and composite additive.

[0097] The molar ratio of the isocyanate to the modified polyol is 1.8:1.

[0098] The isocyanates are 2,2'-bis(4-isobutylisoamyl)propane and 2,4-diphenylmethane diisocyanate in a molar ratio of 3:7.

[0099] The method for producing the modified polyol is as follows:

[0100] S11 (activation) Diglycerin is added to chloroform, then triethylamine and toluenesulfonyl chloride are added, and the reaction is carried out at 5°C for 16 hours to replace one of the terminal hydroxyl groups of diglycerin with a toluenesulfonate group. After the reaction is complete, 1 mol / L aqueous hydrochloric acid is added to the reaction mixture and extracted to obtain the organic phase. Excess anhydrous sodium carbonate is added to the organic phase, and after thorough stirring, the mixture is filtered. The filtrate is added to excess anhydrous diethyl ether and stirred thoroughly to precipitate a white precipitate, which is then filtered by suction and dried to obtain activated diglycerin.

[0101] S12 (Modification of silane) Activated diglycerin is added to DMSO, followed by potassium trimethylsilanolate, and a nucleophilic substitution reaction is carried out at room temperature for 10 hours. After the reaction is complete, the supernatant is collected by centrifugation and concentrated under reduced pressure to obtain the crude product. The crude product is extracted and dried over anhydrous sodium sulfate to obtain the diglycerin-silane product.

[0102] S13 (Pyridine modification) The diglycerin-silane product is added to DMSO, and then 2-pyridyldithiocarbonate and potassium carbonate are added. The reaction is carried out at 50°C for 8 hours to graft a pyridyl group onto the other terminal hydroxyl group of the diglycerin-silane product. After the reaction is complete, the supernatant is collected by centrifugation and concentrated under reduced pressure to obtain the crude product. The crude product is extracted, dried over anhydrous sodium sulfate, and distilled under reduced pressure to obtain a modified polyol containing silane and pyridyl groups.

[0103] The molar ratio of diglycerin to toluenesulfonyl chloride in S11 is 1:2.4.

[0104] In S11, triethylamine is a basic catalyst, and its amount added is 2% of the mass of diglycerin.

[0105] The amount of trimethylsilanolate potassium added in S12 is 30% of the activated diglycerin mass.

[0106] The amount of 2-pyridyldithiocarbonate added in S13 is 28% of the mass of the diglycerin-silane product.

[0107] The amount of potassium carbonate added in step S13 is the amount necessary to adjust the pH of the reaction system to 9.

[0108] The aforementioned bifunctional compound is 2-methyl-1,5-pentanediamine, and its mole fraction is 50% of the total amount of isocyanate and modified polyol.

[0109] The composite additive consists of nanosilicon dioxide and nanocalcium carbonate in a mass ratio of 3:1.5, with a particle size of 80 nm for the nanosilicon dioxide and nanocalcium carbonate.

[0110] The amount of the aforementioned compound additive added is 1.5% of the total mass of the spandex raw material.

[0111] The method for producing polyurethane elastic fibers used in the arbitrarily cut face material is as follows.

[0112] S21: After dehydrating the modified polyol under reduced pressure at 125°C for 2.5 hours, the compound additive is added and stirred uniformly. When the temperature drops to 80°C, the isocyanate is added and stirred thoroughly. Then dibutyltin dilaurate is added and the reaction is allowed to proceed for 3 hours, followed by cooling for 80 minutes to obtain the prepolymer.

[0113] The S22:S21 prepolymer is dissolved in DMF to make a 20% solution. A bifunctional compound is added, and the mixture is reacted at 35°C for 2 hours. After maturation, filtration, and defoaming, a spinning solution with a viscosity of 4000 poise (40°C) is obtained.

[0114] S23: The spinning solution from S22 is measured using a metering pump and extruded from the spinneret into the spinning duct. Upon heating, the solvent evaporates and solidifies to form a tow (bundle of yarn). This is then stretched, lubricated, and heat-set to obtain the polyurethane elastic fiber.

[0115] The amount of dibutyltin dilaurate added in S21 is 0.12% of the total mass of the raw materials.

[0116] The maturation temperature in S22 is 70°C and the maturation time is 12 hours.

[0117] In step S23, the temperature of the spinning duct is 270°C and the speed is 800 m / min.

[0118] The stretch ratio in S23 is 2 times.

[0119] In step S23, the temperature of the heat set was 175°C and the time was 45 seconds.

[0120] Ratio 1 The difference between this example and Example 1 is that the isocyanates are 2,2'-bis(4-isobutylisoamyl)propane and 2,4-diphenylmethane diisocyanate in a molar ratio of 1:1, and otherwise it is the same as Example 1. This ratio is set to 1.

[0121] Ratio Proportionality 2 The difference between this example and Example 1 is that the isocyanates are 2,2'-bis(4-isobutylisoamyl)propane and 2,4-diphenylmethane diisocyanate in a molar ratio of 2:6, and otherwise it is the same as Example 1. This ratio is set to 2.

[0122] Ratio Proportionality 3 Example 1, which is representative, was selected, and the modified polyol was prepared by modifying only the pyridyl group on the diglycerin without modifying the silane, with all other aspects being the same as in Example 1. This was designated as ratio 3.

[0123] Ratio Proportionality 4 Example 1, which is representative, was selected, and the modified polyol was prepared by modifying only the silane group on the diglycerin and not modifying the pyridyl group, with all other aspects being the same as in Example 1. This was designated as ratio 4.

[0124] The performance of polyurethane elastic fibers prepared using the examples and proportional methods was evaluated. Furthermore, after heat treatment at 140°C for 2 hours, the reduction in strength and elongation at break were measured. Details are shown in Table 1. Table 1 JPEG0007917940000001.jpg50165

[0125] As is clear from Table 1, Examples 1-3 exhibit excellent mechanical performance while also possessing good thermal set efficiency and thermal stability.

[0126] The performance of both the proportionality 1 and proportionality 2 models is slightly reduced due to the use of different molar ratios of isocyanates. This indicates that 2,2'-bis(4-isobutylisoamyl)propane and 2,4-diphenylmethane diisocyanate in a molar ratio of 3:7 provides superior mechanical performance, heat resistance, and thermal settling efficiency.

[0127] A ratio of 3 indicates that the silane groups on the modified polyol and the hydroxyl groups on the surface of the composite additive form a chemical crosslink, resulting in improved mechanical properties and thermal stability.

[0128] A ratio of 4 indicates that modified polyols with pyridyl groups improve the heat-setting efficiency of fibers, reduce the heat-setting temperature, and also provide good results in blending with heat-resistant materials such as wool and silk.

[0129] Unless otherwise specified, all ratios described in this invention refer to mass ratios, and all percentages mentioned refer to mass percent. Furthermore, all raw materials are commercially available.

[0130] Finally, it should be noted that the above description is merely a preferred embodiment of the present invention and does not limit it. Although the present invention has been described in detail based on the above embodiments, it is still possible for those skilled in the art to modify the technical solutions described in each of the above embodiments or to substitute some of the technical features with equivalent ones.

[0131] Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should all be included within the scope of protection of the present invention.

Claims

1. A method for manufacturing polyurethane elastic fibers to be used in fabrics that can be cut arbitrarily, The raw materials used in the production of the aforementioned polyurethane elastic fiber include isocyanate, modified polyol, difunctional compound, and composite additive. The following steps are included: S21. The modified polyol is dehydrated under reduced pressure at 115-125°C for 2-3 hours, then a compound additive is added and the mixture is uniformly stirred. When the temperature drops to 80-85°C, isocyanate is added and the mixture is stirred thoroughly. Then dibutyltin dilaurate is added and the mixture is reacted for 2-3 hours, after which it is cooled for 60-80 minutes to obtain a prepolymer. S22, the prepolymer obtained in S21 is dissolved in DMF to make a 20% solution, a bifunctional compound is added and the mixture is reacted at 30-35°C for 2-3 hours, followed by maturation, filtration and defoaming to obtain a spinning stock with a viscosity of 3000-4000 poise (40°C); S23, the process of measuring the spinning solution from S22 with a metering pump, extruding it from the spinneret and introducing it into the spinning duct, then heating to evaporate the solvent and solidify it to form a tow (bundle of yarn), and then stretching, applying an oil agent and heat setting the tow to obtain the polyurethane elastic fiber; Here, the amount of dibutyltin dilaurate added in S21 is 0.08 to 0.12% of the total mass of the raw materials. In S23, the temperature of the heat set was 170-175°C, and the time was 40-50 seconds. The isocyanate consists of 2,2'-bis(4-isobutylisoamyl)propane and 2,4-diphenylmethane diisocyanate in a molar ratio of 3:

7. A manufacturing method characterized by the following features.

2. The method for producing the modified polyol according to claim 1, characterized in that the modified polyol contains a silane group and a pyridyl group.

3. The molar ratio of the isocyanate to the modified polyol is 1.8 to 2:

1. The manufacturing method according to claim 2, characterized in that it

4. The method for producing the modified polyol includes activation, silane modification, and pyridine modification. The manufacturing method according to claim 2, characterized in that it

5. The activation process includes adding diglycerin to chloroform, adding triethylamine and toluenesulfonyl chloride, reacting at 0-5°C for 12-16 hours, and after the reaction is complete, adding a 1 mol / L aqueous hydrochloric acid solution to the reaction mixture to extract and obtain an organic phase. Adding an excess of anhydrous sodium carbonate to the organic phase, stirring thoroughly, and filtering, adding an excess of anhydrous diethyl ether to the filtrate, stirring thoroughly to precipitate a white precipitate, and obtaining activated diglycerin after suction filtration and drying. The molar ratio of diglycerin to toluenesulfonyl chloride is 1:2 to 2.

4. The triethylamine is a basic catalyst, and its amount added is 1-2% of the mass of diglycerin. The manufacturing method according to feature 4.

6. The modification of the silane includes the steps of adding activated diglycerin to DMSO, adding potassium trimethylsilanolate, carrying out a nucleophilic substitution reaction at room temperature for 8 to 10 hours, centrifugation after the reaction to obtain the supernatant, extracting the crude product obtained by concentrating under reduced pressure, and drying over anhydrous sodium sulfate to obtain the diglycerin-silane product. The amount of potassium trimethylsilanolate added is 20-30% of the mass of activated diglycerin. The manufacturing method according to feature 4.

7. The modification of pyridine includes the steps of adding the diglycerin-silane product to DMSO, adding 2-pyridyldithiocarbonate and potassium carbonate, reacting at 40-50°C for 6-8 hours, centrifugation after the reaction to obtain the supernatant, extracting the crude product obtained by vacuum concentration, drying over anhydrous sodium sulfate, and vacuum distillation to obtain a modified polyol containing silane and pyridyl groups. The amount of 2-pyridyldithiocarbonate added is 23-28% of the mass of the diglycerin-silane product. The amount of potassium carbonate added is the amount that adjusts the pH of the reaction system to 8-9. The manufacturing method according to feature 4.

8. The aforementioned bifunctional compound is one or more selected from the group consisting of 2-methyl-1,5-pentanediamine, 1,4-cyclohexanediol, neopentyl glycol, diethanolamine, and 3,5-bis(methylthio)toluenediamine. The manufacturing method according to claim 2, characterized in that it

9. The aforementioned compound additive is one or more selected from the group consisting of sodium benzoate, nano silicon dioxide, and nano calcium carbonate, and the amount of the compound additive added is 1 to 1.5% of the total mass of the spandex raw material. The manufacturing method according to claim 2, characterized in that it

10. Use of arbitrarily cuttable polyurethane elastic fibers for fabric, manufactured by the manufacturing method described in any one of claims 1 to 9, in the manufacture of underwear and home wear.

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