Chemically modified high-strength high-temperature-resistant polyurethane fiber and preparation method thereof

Abstract

The invention relates to a chemically modified high-strength high-temperature-resistant polyurethane fiber and a preparation method thereof.The preparation method comprises the following steps that 1, oligomer mixed polyol and diisocyanate are subjected to a full prepolymerization reaction, a solvent is added for full dissolution, and a-NCO-terminated prepolymer polyurethane formate solution is obtained; 2) adding hydroxyalkyl silane and a catalyst into the prepared prepolymer, and fully reacting to obtain a modified prepolymer; (3) carrying out chain extension reaction and chain termination reaction on the prepared modified prepolymer to obtain a polyurethane urea solution; (4) adding an antioxidant, an ultraviolet light absorber, an anti-yellowing agent, a delustering agent and a lubricating and releasing agent into the polyurethane urea solution to prepare a polyurethane spinning solution; and (5) preparing the high-strength high-temperature-resistant polyurethane from the prepared polyurethane spinning solution by virtue of a dry spinning system. According to the invention, a polyurethane molecular chain is subjected to functional chemical modification, so that the product has the characteristics of high temperature resistance and high strength.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of high polymer material modification, and particularly relates to a chemically modified high-strength high-temperature-resistant polyurethane fiber and a preparation method thereof. BACKGROUND

[0002] Polyurethane (PU) is widely used in the fields of textiles, automobiles, medical treatment and the like due to its excellent elasticity, wear resistance and processability. However, the traditional polyurethane has problems of insufficient heat resistance (thermal decomposition temperature < 300℃), low-temperature brittleness (-40℃ elongation at break < 50%), high water absorption (> 3%) and the like, which limit its application in extreme environments and high-value-added fields.

[0003] In order to realize the high-strength and high-temperature-resistant characteristics of polyurethane fibers, polyurethane modification technology is proposed. The existing modification technology is mainly divided into two categories:

[0004] (1) Physical blending: such as adding nano materials (such as nano SiO2) or flame retardants, which can partially improve the performance, but easily leads to phase separation or mechanical performance decline; for example, the patent CN105420844B improves the heat resistance by adding metal hydroxide, but leads to too strong rigidity of the material and loss of elasticity.

[0005] (2) Single chemical modification: for example, the patent CN119285899A improves the hydrophobicity by using a fluorine-containing monomer, but does not solve the problems of heat resistance and biocompatibility; the patent CN117801209A improves the toughness by modifying the epoxy resin with polyurethane, but the compatibility is still limited; the patent CN109183188A uses imide structure copolymerization modification, which improves the heat resistance, but the synthesis process is complex and the cost is high. The existing technology focuses on single performance optimization, lacks a systematic solution for the synergistic modification of the multifunctional polyurethane, and has insufficient feasibility for industrial production. Therefore, there is an urgent need for an efficient and low-cost chemical modification method to significantly improve the thermal stability and tensile property of the polyurethane without sacrificing the original performance of the polyurethane. SUMMARY

[0006] The application aims to solve the problem of insufficient comprehensive performance of the traditional polyurethane material, and simultaneously improves the high-temperature resistance and high-strength property of the polyurethane by using a composite chemical modification technology, and simplifies the process flow to adapt to industrial production.

[0007] In one aspect, the application provides a preparation method of a chemically modified high-strength high-temperature-resistant polyurethane fiber, which comprises the following steps:

[0008] Step 1. Reacting the oligomer mixed polyol with excess diisocyanate at 90℃ for 2 hours to generate a -NCO terminated prepolymer, preparing a -NCO terminated urethane prepolymer, and obtaining a prepolymer;

[0009] Step 2. Add the hydroxyl alkyl silane modifier (6.0wt%-12.0wt%) and catalyst (0.05wt%-0.2wt% dibutyl tin dilaurate) to the prepolymer prepared above, and react at 80°C for 3 hours to obtain a modified prepolymer;

[0010] Step 3. Add N,N-dimethylacetamide to the modified prepolymer prepared above to form a solution, the concentration of the solution being 25wt%-40wt%; cool the solution to below 15°C, and add a mixed amine solution to carry out chain extension and chain termination reactions to obtain a polyurethane urea solution;

[0011] Step 4. Add antioxidants, ultraviolet absorbers, anti-yellowing agents, flatting agents, lubricity agents, and other functional additives to the polyurethane urea solution prepared above, the content of each functional additive being 0.1wt%-2.0wt%, and after thoroughly mixing, a polyurethane spinning dope is prepared;

[0012] Step 5. Use a dry spinning system to spray and draw the polyurethane spinning dope prepared above into a fiber, and as the solvent evaporates and dries, a high-strength high-temperature resistant polyurethane fiber is obtained.

[0013] The oligomer mixed polyols include at least one polypropylene glycol, and the content of the polypropylene glycol is 40wt%-70wt% of all the mixed polyols.

[0014] The oligomer mixed polyols are a mixture of polytetramethylene ether glycol (PTMG1800) and polypropylene glycol with a number average molecular weight of 400-2000.

[0015] The hydroxyl alkyl silane modifier is 6.0wt%-12.0wt% of hydroxyl alkyl terminated polydimethylsiloxane and / or hydroxyl alkyl double terminated polydimethylsiloxane.

[0016] The mixed amine solution is a mixed solution of a chain extender and a chain terminator, the chain extender being selected from ethylenediamine, 1,2-propanediamine, 2-methylpentanediamine, and / or polyetheramine D230, and the chain terminator being selected from diethylamine, dibutylamine, aliphatic secondary amine, and / or N-phenyl-3-aminopropyl trimethoxysilane.

[0017] At least one of the chain extenders is 2-methylpentanediamine, and the content of the 2-methylpentanediamine is 10mol%-30mol% of all the chain extenders.

[0018] The diisocyanate is 4,4-diisocyanate or 2,4-diisocyanate, or a mixture of the two.

[0019] The mass concentration of the polyurethane spinning dope is 30wt%-50wt%.

[0020] The high-strength high-temperature-resistant polyurethane fiber prepared by the method has high heat resistance, and can prevent the product from losing elasticity at high temperature when used in a high-demand field.

[0021] In another aspect, the application also provides a chemically modified high-strength high-temperature-resistant polyurethane fiber prepared by the method.

[0022] Beneficial effects: The application uses high-content polypropylene glycol as a main raw material for polymerization, and simultaneously performs chemical modification by adding hydroxylalkyl silane to the prepolymer, uses a siloxane network to enhance thermal stability and hydrophobicity, and obtains a modified prepolymer; rigid 2-methylpentanediamine is introduced into the chain extender to greatly improve the rigidity of the high-molecular hard segment and the hydrogen bond content, and thus improve the heat resistance and high-strength value of the product, the cost is low, the product is easy to prepare, has good chemical stability, ensures the spinnability of the dope, and does not affect the conventional performance of the fiber.

[0023] The high-strength high-temperature-resistant polyurethane fiber prepared by the application solves the problems of insufficient breaking strength and high-temperature resistance, belongs to a high-value-added functional polyurethane fiber, and has high application prospects in the market. DETAILED DESCRIPTION

[0024] The application will be described in detail below with examples, but the examples should not be understood as limiting the application in any sense.

[0025] The application provides a preparation method of a chemically modified high-strength high-temperature-resistant polyurethane fiber, which comprises the following steps:

[0026] Step 1. Reacting oligomer mixed polyol and excess diisocyanate at 90℃ for 2 hours to generate an -NCO terminated prepolymer, preparing a -NCO terminated urethane prepolymer, and obtaining a prepolymer;

[0027] Step 2. Adding hydroxylalkyl silane modifier (6.0wt%-12.0wt%) and catalyst (0.05wt%-0.2wt% dibutyltin dilaurate) to the prepared prepolymer, and reacting at 80℃ for 3 hours to obtain a modified prepolymer;

[0028] Step 3. Adding N,N-dimethylacetamide to the prepared modified prepolymer to form a solution, the concentration of the solution is 25wt%-40wt%; cooling the solution to below 15℃, adding a mixed amine solution to perform chain extension reaction and chain termination reaction, and obtaining a polyurethane urea solution;

[0029] Step 4. To the polyurethane urea solution prepared above, antioxidant, ultraviolet absorber, anti-yellowing agent, flatting agent, lubricant and other functional additives are added, the content of each functional additive is 0.1wt%-2.0wt%, after fully stirring and mixing, the polyurethane spinning dope is prepared;

[0030] Step 5. The polyurethane spinning dope prepared above is sprayed and stretched into filaments by means of dry spinning system, and high-strength high-temperature-resistant polyurethane fibers are obtained after solvent evaporation and drying.

[0031] Example 1:

[0032] 10.0Kg of polytetramethylene ether glycol (PTMG1800) and 10.0Kg of polypropylene glycol are added to a reaction kettle, then 5.0Kg of 4,4-diphenyl methane diisocyanate is added, and the reaction is carried out at 90℃ for 2h under high-speed stirring to prepare a urethane prepolymer capped with -NCO, and a prepolymer is obtained.

[0033] 2.0Kg of modified hydroxyalkyl-capped polydimethylsiloxane and 2.5Kg of dibutyltin dilaurate are added to the prepared prepolymer, and the reaction is carried out at 80℃ for 3h to obtain a modified prepolymer;

[0034] 40Kg of N,N-dimethylacetamide is added to the modified prepolymer to prepare a prepolymer solution, the solution is cooled to below 15℃, and a N,N-dimethylacetamide solution containing 0.45Kg of ethylenediamine, 0.040Kg of 2-methylpentanediamine and 0.064Kg of diethylamine (the mass concentration of amine is 6%) is gradually added to carry out chain extension reaction and chain termination reaction, and a polyurethane urea solution is obtained;

[0035] Antioxidant, anti-yellowing agent, ultraviolet absorber and lubricant are added to the obtained polyurethane urea solution to obtain a polyurethane spinning dope;

[0036] The polyurethane spinning dope prepared above is sprayed and stretched into filaments by means of dry spinning system, and high-strength high-temperature-resistant polyurethane fibers are obtained after solvent evaporation and drying.

[0037] Example 2:

[0038] The experimental method is the same as that in Example 1, 2Kg of hydroxyalkyl-capped polydimethylsiloxane is changed to 2Kg of hydroxyalkyl-capped polydimethylsiloxane, and then antioxidant, anti-yellowing agent, ultraviolet absorber and lubricant are added to obtain a polyurethane spinning dope;

[0039] The polyurethane spinning dope prepared above is sprayed and stretched into filaments by means of dry spinning system, and high-strength high-temperature-resistant polyurethane fibers are obtained after solvent evaporation and drying.

[0040] Example 3:

[0041] The experimental method is the same as that of Example 1, 1 Kg of hydroxyalkyl-terminated polydimethylsiloxane and 1 Kg of hydroxyalkyl-terminated polydimethylsiloxane are changed to 0.5 Kg of hydroxyalkyl-terminated polydimethylsiloxane and 1.5 Kg of hydroxyalkyl-terminated polydimethylsiloxane, and then antioxidants, anti-yellowing agents, ultraviolet absorbers, and lubricating and softening agents are added to obtain a polyurethane spinning solution;

[0042] The above-prepared polyurethane spinning solution is sprayed, stretched into a filament, and dried with the solvent evaporating by means of a dry spinning system, and a high-strength and high-temperature-resistant polyurethane fiber is obtained.

[0043] Example 4:

[0044] The experimental method is the same as that of Example 1, 1 Kg of hydroxyalkyl-terminated polydimethylsiloxane and 1 Kg of hydroxyalkyl-terminated polydimethylsiloxane are changed to 0.5 Kg of hydroxyalkyl-terminated polydimethylsiloxane and 1.5 Kg of hydroxyalkyl-terminated polydimethylsiloxane, and then antioxidants, anti-yellowing agents, ultraviolet absorbers, and lubricating and softening agents are added to obtain a polyurethane spinning solution;

[0045] The above-prepared polyurethane spinning solution is sprayed, stretched into a filament, and dried with the solvent evaporating by means of a dry spinning system, and a high-strength and high-temperature-resistant polyurethane fiber is obtained.

[0046] Example 5:

[0047] The experimental method is the same as that of Example 1, 0.5 Kg of hydroxyalkyl-terminated polydimethylsiloxane and 1.5 Kg of hydroxyalkyl-terminated polydimethylsiloxane are changed to 1.5 Kg of hydroxyalkyl-terminated polydimethylsiloxane and 0.5 Kg of hydroxyalkyl-terminated polydimethylsiloxane, and then antioxidants, anti-yellowing agents, ultraviolet absorbers, and lubricating and softening agents are added to obtain a polyurethane spinning solution;

[0048] The above-prepared polyurethane spinning solution is sprayed, stretched into a filament, and dried with the solvent evaporating by means of a dry spinning system, and a high-strength and high-temperature-resistant polyurethane fiber is obtained.

[0049] Comparative Example:

[0050] 10.0 Kg of polytetramethylene ether glycol (PTMG1800) and 10.0 Kg of polypropylene glycol are added to a reaction kettle, and then 5.0 Kg of 4,4-diphenylmethane diisocyanate is added, and the mixture is stirred at 90°C for 2 h to prepare a urethane prepolymer terminated with -NCO, and a prepolymer is obtained.

[0051] The modified prepolymer is added with 42 Kg of N, N-dimethylacetamide to prepare a prepolymer solution, the solution is cooled to below 15℃, and a solution containing 0.45 Kg of ethylenediamine, 0.040 Kg of 2-methylpentanediamine and 0.064 Kg of diethylamine in N, N-dimethylacetamide (mass concentration of amine is 6%) is gradually added to carry out chain extension reaction and chain termination reaction, to obtain a polyurethane urea solution;

[0052] An antioxidant, an anti-yellowing agent, an ultraviolet absorber and a lubricant are added to the obtained polyurethane urea solution to obtain a polyurethane spinning dope;

[0053] The polyurethane spinning dope prepared above is sprayed and stretched into filaments by means of a dry spinning system, and the solvent is volatilized and dried, to obtain high-strength high-temperature-resistant polyurethane fibers.

[0054] Table 1: Physical property indexes and high-strength high-temperature-resistant data of polyurethane elastic fibers of each example

[0055]

[0056] As can be seen from Table 1, the high-temperature-resistant polyurethane of the present application has excellent heat resistance and high-strength performance, and has no adverse effect on the conventional performance of the fibers, and has a wide market application prospect.

[0057] The above only illustrates the exemplary embodiments of the present application, and is not intended to limit the present application, and any modification, equivalent replacement and improvement within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for preparing chemically modified high-strength, high-temperature resistant polyurethane fiber, characterized in that, The method includes the following steps: Step 1. Mix the oligomer with polyol and excess diisocyanate and react at 90°C for 2 hours to generate -NCO-terminated prepolymer, prepare urethane prepolymer with -NCO-terminated prepolymer, and obtain the prepolymer; Step 2. Add hydroxyalkylsilane (6.0-12.0 wt%) and catalyst (0.05 wt%-0.2 wt% dibutyltin dilaurate) to the prepolymer prepared above, and react at 80°C for 3 hours to obtain the modified prepolymer; Step 3. Add N,N-dimethylacetamide to the modified prepolymer prepared above and dissolve it completely into a solution with a concentration of 25wt%-40wt%. Cool the solution to below 15°C and add a mixed amine solution to carry out chain extension and chain termination reactions to obtain a polyurethane urea solution. Step 4. Add antioxidants, ultraviolet absorbers, anti-yellowing agents, matting agents, lubricants and solubilizers to the above polyurethane urea solution. The content of each functional additive is 0.1wt%-2.0wt%. After thorough stirring and mixing, a polyurethane spinning solution is prepared. Step 5. The polyurethane spinning solution prepared above is sprayed and stretched into filaments using a dry spinning system, and then dried as the solvent evaporates to obtain high-strength, high-temperature resistant polyurethane fibers.

2. The method for preparing chemically modified high-strength, high-temperature resistant polyurethane fiber according to claim 1, characterized in that, At least one of the oligomeric polyols is polypropylene glycol, and its content is 40wt%-70wt% of all the mixed polyols.

3. The method for preparing chemically modified high-strength, high-temperature resistant polyurethane fiber according to claim 2, characterized in that, The oligomer mixed polyol is a mixture of polytetramethylene ether glycol (PTMG1800) and polypropylene glycol with a number average molecular weight of 400-2000.

4. The method for preparing chemically modified high-strength, high-temperature resistant polyurethane fiber according to claim 1, characterized in that, The hydroxyalkyl silane modifier is 6.0wt%-12.0wt% of hydroxyalkyl-terminated polydimethylsiloxane and / or hydroxyalkyl-dual-terminated polydimethylsiloxane.

5. The method for preparing chemically modified high-strength, high-temperature resistant polyurethane fiber according to claim 1, characterized in that, The mixed amine solution is a mixture of chain extender and chain terminator. The chain extender is selected from ethylenediamine, 1,2-propanediamine, 2-methylpentanediamine and / or polyetheramine D230; the chain terminator is selected from diethylamine, dibutylamine, aliphatic secondary amine and / or N-phenyl-3-aminopropyltrimethoxysilane.

6. The method for preparing chemically modified high-strength, high-temperature resistant polyurethane fiber according to claim 5, characterized in that... At least one of the chain extenders is 2-methylpentanediamine, and the content of 2-methylpentanediamine is 10 mol%-30 mol% of all chain extenders.

7. The method for preparing chemically modified high-strength, high-temperature resistant polyurethane fiber according to claim 1, characterized in that, The diisocyanate is 4,4-diisocyanate or 2,4-diisocyanate, or a mixture of both.

8. The method for preparing chemically modified high-strength, high-temperature resistant polyurethane fiber according to claim 1, characterized in that, The polyurethane spinning solution has a mass concentration of 30wt%-50wt%.

9. A chemically modified high-strength, high-temperature resistant polyurethane fiber prepared according to any one of claims 1-8.

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