A method for preparing high-performance polyamide fiber

Abstract

The invention relates to the field of environmental protection, and in particular to a method for preparing high-performance polyamide fiber. The invention prepares the high-performance polyamide fiber through dry swelling, degassing, spinning, coagulation, drawing, decomplexation, heat setting and other process processes. The invention shields the hydrogen bonds between PA6 molecules through a method of local complexation with a complexing agent, changes the crystallization properties of PA6, and then stretches PA6 and decomplexes to restore the hydrogen bonds, thereby obtaining the high-performance polyamide fiber. The high-performance polyamide fiber prepared by the invention has significantly improved mechanical properties, further improved fiber orientation and crystallinity, and a denser fiber microstructure. The finished fiber can be stretched up to 10 times, has a maximum modulus of 32.33 GPa, and a strength of 0.53 GPa.

Description

Technical Field

[0001] The invention relates to the field of environmental protection, and in particular to a method for preparing high-performance polyamide fiber. Background Art

[0002] Polyamide fiber is commonly known as nylon in my country. It has excellent mechanical properties, wear resistance and chemical corrosion resistance, and is widely used in clothing, home textiles and industrial fields. At present, the production technology of conventional polyamide fiber filaments and staple fibers has been relatively complete. With the continuous improvement of people's quality of life, the demand for polyamide fiber products with high sensitivity such as fine denier, ultrafine denier and special-shaped cross-section, high functionality such as moisture absorption and perspiration, antibacterial, anti-ultraviolet and other improved wearing performance will grow rapidly; secondly, by utilizing the excellent properties of polyamide fibers, they are modified to give them special functions such as high temperature resistance, flame retardancy, high strength and high modulus, etc. The application of these high-functional and high-performance polyamide fibers in the growing national economy and national defense construction is increasing.

[0003] CN201711091330.6: Preparation method of chlorine-containing high-performance heterocyclic aromatic polyamide fiber. The present invention belongs to the field of organic fiber materials. It aims to solve the problem that the thermal stability and flame retardancy of existing heterocyclic aromatic fibers need to be improved. Preparation method: 1. Add p-phenylenediamine, 2-(4-aminophenyl)-5-aminobenzimidazole, chlorine-containing p-phenylenediamine and 2,2'-butylenebis[5-aminobenzoxazole] to a reactor filled with a composite solvent. After complete dissolution, reduce the temperature in the reactor to -10 to 10°C, add terephthaloyl chloride, react for 0.5 to 2 hours, heat to 60 to 90°C, react for 2 to 5 hours, and obtain chlorine-containing heterocyclic aromatic polyamide; 2. Degassing and wet spinning. The chlorine-containing high-performance heterocyclic aromatic polyamide fiber of the present invention introduces heterocyclic rings and chlorine-containing side groups into the polymer main chain, thereby improving its surface activity, achieving a breaking strength of 3.50-5.0 GPa, and a limiting oxygen index of 30%-50%.

[0004] CN201811593274.0: A method for producing a continuous polymerization melt-spun functional polyamide fiber and the functional polyamide fiber are disclosed. The method comprises: continuously conveying a functional powder slurry pre-dispersed material prepared by water, caprolactam and functional powder to a functional powder slurry multi-stage grinding device for grinding and dispersion; the obtained functional powder slurry is uniformly mixed with the caprolactam melt and the catalyst by a dynamic mixer, and then the temperature is adjusted by a heat exchanger and then enters a hydrolysis reactor for ring-opening reaction; the obtained functional caprolactam oligomer melt is removed from the oligomer melt dehydrator to remove excess water and then enters a pre-polymerization reactor for addition polymerization reaction; the obtained functional polyamide prepolymer melt is removed from the prepolymer melt dehydrator to remove residual water and then enters a post-polymerization reactor for condensation reaction; the obtained functional polyamide melt is directly conveyed to a spinning box for spinning after the caprolactam monomer is removed by a thin film evaporation devolatilization system to obtain a functional polyamide fiber. The functional powder in the functional polyamide fiber is highly uniformly dispersed.

[0005] CN202011331181.8: The present invention relates to a method for preparing a flame-retardant polyamide fiber material, which uses a flame-retardant polyamide fiber material preparation device, the flame-retardant polyamide fiber material preparation device includes a base and a pelletizing device, and the upper surface of the base is provided with a pelletizing device. The present invention can solve the problems currently existing in the preparation of flame-retardant polyamide fiber materials: the existing pelletizing process of the raw material polyamide fiber for preparing flame-retardant polyamide fiber materials is difficult to ensure the uniformity of the size of the polyamide fiber pellets, and there is also a problem of material clamping between the cutter and the polyamide fiber pellets, which also makes the size of the pellets uneven. In this way, when the polyamide fiber pellets are mixed with other materials to prepare the flame-retardant polyamide fiber material, it is difficult to fully mix with other materials, so the functional effect of the prepared flame-retardant polyamide fiber material will be reduced, which not only wastes time but also wastes materials.

[0006] The above patents and prior art mainly use various small molecule organic or inorganic complexes to plasticize polyamide to inhibit its intermolecular hydrogen bonds. Common complexes include iodine, anhydrous ammonia, metal chlorides and rare earths to modify polyamide. These methods can reduce the crystallinity of polyamide to varying degrees and increase its stretch multiple. However, it should be pointed out that most of the modification methods have certain defects, such as anhydrous ammonia and iodine are volatile, gallium trichloride is too active and toxic, and the degree of complex modification of lithium chloride and zinc chloride is limited, etc. Summary of the invention

[0007] In order to solve the above problems, the present invention provides a method for preparing high-performance polyamide fiber, and the operating steps are as follows:

[0008] S1: According to the mass fractions, weigh 55-80 parts of solvent, 3-7 parts of complexing agent, and 32-38 parts of PA6, swell at room temperature under nitrogen protection, dissolve evenly, and degas by centrifugation;

[0009] S2: After passing through a spinneret, a coagulation bath and then winding, a complexed raw fiber is obtained;

[0010] S3: The complexed raw yarn is initially drawn at room temperature, and then decomplexed and heat-set to obtain high-performance polyamide fiber.

[0011] The solvent is formic acid or acetone or dichloromethane or chloroform or acetone.

[0012] The decomplexation is performed by placing the complexed raw silk into 30-45 parts of ethanol and 40-60 parts of water for 3-5 hours.

[0013] The heat setting temperature is 160-175° C. and the time is 1-2 minutes.

[0014] The complexing agent preparation method is:

[0015] According to weight, 0.05-0.7 parts of lithium acrylate, 100-120 parts of amino ionic liquid, 5-12 parts of cerium methacrylate, and 0.8-2.5 parts of tetramethylguanidine are added to a reaction kettle, nitrogen is introduced, and the mixture is stirred at 60-80° C. for 2-4 hours to obtain a complexing agent.

[0016] The amino-type ionic liquid is a mixture of one or more of 1-aminopropyl-3-methylimidazolium nitrate, 1-aminopropyl-3-methylimidazolium tetrafluoroborate, 1-aminopropyl-3-methylimidazolium bromide, and 1-aminoethyl-3-methylimidazolium nitrate in any ratio.

[0017] The preparation method of PA6 is as follows:

[0018] S1: Add caprolactam in the polymerization reactor according to the mass fraction, raise the temperature to 80-90°C, and after the caprolactam in the reactor is completely melted, evacuate to -0.06-0.08Mpa and stir;

[0019] S2: Add the catalyst, continue to raise the temperature to 90-100°C, continue to evacuate for 1-2 hours, and stir;

[0020] S3: Add activator and thermal dispersant, continue to heat to 120-140°C, stir for 1-3h;

[0021] S4: After the reaction is completed, the material is placed in a container, washed with boiling water three times, each time boiling for 45-60 minutes, vacuum filtered, and dried to obtain PA6.

[0022] The catalyst is sodium hydroxide.

[0023] The activator is diisocyanate.

[0024] The heat dispersant is kerosene.

[0025] Reaction mechanism:

[0026] The prior art uses ionic liquid as a complexing agent, but still has the disadvantage of limited degree of complexing modification. The present invention uses lithium acrylate, amino-type ionic liquid, and cerium methacrylate to undergo amino-ene Michael addition reaction to obtain a complexing agent with more prominent complexing effect.

[0027] Technical effects:

[0028] Compared with the prior art, the method for preparing high-performance polyamide fiber of the present invention has the following significant advantages:

[0029] 1. The present invention shields the hydrogen bonds between PA6 molecules by a method of local complexation with a complexing agent, changes the crystallization properties of PA6, and then stretches PA6 and then decomplexes to restore the hydrogen bonds, thereby obtaining high-performance polyamide fibers; the high-performance polyamide fibers prepared by the present invention have good strength, wear resistance, elastic recovery rate, hygroscopicity and other properties;

[0030] 2. The high-performance polyamide fiber prepared by the present invention has significantly improved mechanical properties, the fiber orientation and crystallinity are further improved, the fiber microstructure is denser, the finished fiber can be stretched up to 10 times, the maximum modulus reaches 32.33GPa, and the strength reaches 0.53GPa. DETAILED DESCRIPTION

[0031] The invention will be further described below by means of specific embodiments:

[0032] Testing standard reference: High and low temperature mechanical properties test guideline for fiber reinforced plastics GB / T9979-2005.

[0033] Example 1

[0034] A method for preparing high-performance polyamide fiber, the operating steps are:

[0035] S1: Weigh 55g solvent, 3g complexing agent, and 32g PA6, swell at room temperature under nitrogen protection, dissolve evenly, and degas by centrifugation;

[0036] S2: After passing through a spinneret, a coagulation bath and then winding, a complexed raw fiber is obtained;

[0037] S3: The complexed raw yarn is initially drawn at room temperature, and then decomplexed and heat-set to obtain high-performance polyamide fiber.

[0038] The solvent is formic acid.

[0039] The decomplexation is performed by placing the complexed raw silk into 30g of ethanol and 40g of water for 3h.

[0040] The heat setting temperature is 160° C. and the time is 1 minute.

[0041] The complexing agent preparation method is:

[0042] 0.05 g of lithium acrylate, 100 g of amino-type ionic liquid, 5 g of cerium methacrylate, and 0.8 g of tetramethylguanidine were added into a reaction kettle, nitrogen was introduced, and the mixture was stirred at 60° C. for 2 h to obtain a complexing agent.

[0043] The amino-type ionic liquid is 1-aminopropyl-3-methylimidazole nitrate.

[0044] The preparation method of PA6 is as follows:

[0045] S1: Add caprolactam into the polymerization reactor, raise the temperature to 80°C, and after the caprolactam in the reactor is completely melted, evacuate to -0.06Mpa and stir;

[0046] S2: Add the catalyst, continue to raise the temperature to 90°C, continue to evacuate for 1 hour, and stir;

[0047] S3: Add activator and thermal dispersant, continue to heat to 120°C, stir for 1 hour;

[0048] S4: After the reaction is completed, the material is placed in a container, washed with boiling water three times, each time boiling for 45 minutes, vacuum filtered, and dried to obtain PA6.

[0049] The catalyst is sodium hydroxide.

[0050] The activator is diisocyanate.

[0051] The heat dispersant is kerosene.

[0052] Example 2

[0053] A method for preparing high-performance polyamide fiber, the operating steps are:

[0054] S1: Weigh 60g solvent, 4g complexing agent, and 34g PA6, swell at room temperature under nitrogen protection, dissolve evenly, and degas by centrifugation;

[0055] S2: After passing through a spinneret, a coagulation bath and then winding, a complexed raw fiber is obtained;

[0056] S3: The complexed raw yarn is initially drawn at room temperature, and then decomplexed and heat-set to obtain high-performance polyamide fiber.

[0057] The solvent is acetone.

[0058] The decomplexation is performed by placing the complexed raw silk into 35g of ethanol and 45g of water for 4h.

[0059] The heat setting temperature is 165° C. and the time is 1 minute.

[0060] The complexing agent preparation method is:

[0061] 0.2 g of lithium acrylate, 105 g of amino-type ionic liquid, 7 g of cerium methacrylate, and 1.5 g of tetramethylguanidine were added into a reaction kettle, nitrogen was introduced, and the mixture was stirred at 65° C. for 3 h to obtain a complexing agent.

[0062] The amino-type ionic liquid is 1-aminopropyl-3-methylimidazolium tetrafluoroborate.

[0063] The preparation method of PA6 is as follows:

[0064] S1: Add caprolactam into the polymerization reactor, raise the temperature to 85°C, and after the caprolactam in the reactor is completely melted, evacuate to -0.07Mpa and stir;

[0065] S2: Add the catalyst, continue to raise the temperature to 95°C, continue to evacuate for 1.5 hours, and stir;

[0066] S3: Add activator and thermal dispersant, continue to heat to 125°C, stir for 2h;

[0067] S4: After the reaction is completed, the material is placed in a container, washed with boiling water three times, each time for 50 minutes, vacuum filtered, and dried to obtain PA6.

[0068] The catalyst is sodium hydroxide.

[0069] The activator is diisocyanate.

[0070] The heat dispersant is kerosene.

[0071] Example 3

[0072] A method for preparing high-performance polyamide fiber, the operating steps are:

[0073] S1: Weigh 70g solvent, 6g complexing agent, and 36g PA6, swell at room temperature under nitrogen protection, dissolve evenly, and degas by centrifugation;

[0074] S2: After passing through a spinneret, a coagulation bath and then winding, a complexed raw fiber is obtained;

[0075] S3: The complexed raw yarn is initially drawn at room temperature, and then decomplexed and heat-set to obtain high-performance polyamide fiber.

[0076] The solvent is dichloromethane.

[0077] The decomplexation is performed by placing the complexed raw silk into 40g of ethanol and 55g of water for 4h.

[0078] The heat setting temperature is 170° C. and the time is 1.5 minutes.

[0079] The complexing agent preparation method is:

[0080] 0.5 g of lithium acrylate, 115 g of amino-type ionic liquid, 10 g of cerium methacrylate, and 2 g of tetramethylguanidine were added into a reaction kettle, nitrogen was introduced, and the mixture was stirred at 75° C. for 3 h to obtain a complexing agent.

[0081] The amino-type ionic liquid is 1-aminoethyl-3-methylimidazole nitrate.

[0082] The preparation method of PA6 is as follows:

[0083] S1: Add caprolactam into the polymerization reactor, raise the temperature to 85°C, and after the caprolactam in the reactor is completely melted, evacuate to -0.08Mpa and stir;

[0084] S2: Add the catalyst, continue to raise the temperature to 95°C, continue to evacuate for 1.5 hours, and stir;

[0085] S3: Add activator and thermal dispersant, continue to heat to 135°C, stir for 2h;

[0086] S4: After the reaction is completed, the material is placed in a container, washed with boiling water three times, each time boiling for 55 minutes, vacuum filtered, and dried to obtain PA6.

[0087] The catalyst is sodium hydroxide.

[0088] The activator is diisocyanate.

[0089] The heat dispersant is kerosene.

[0090] Example 4

[0091] A method for preparing high-performance polyamide fiber, the operating steps are:

[0092] S1: Weigh 80g solvent, 7g complexing agent, and 38g PA6, swell at room temperature under nitrogen protection, dissolve evenly, and degas by centrifugation;

[0093] S2: After passing through a spinneret, a coagulation bath and then winding, a complexed raw fiber is obtained;

[0094] S3: The complexed raw yarn is initially drawn at room temperature, and then decomplexed and heat-set to obtain high-performance polyamide fiber.

[0095] The solvent is acetone.

[0096] The decomplexation is performed by placing the complexed raw silk into 45g of ethanol and 60g of water for 5 hours.

[0097] The heat setting temperature is 175° C. and the time is 2 minutes.

[0098] The complexing agent preparation method is:

[0099] 0.7 g of lithium acrylate, 120 g of amino-type ionic liquid, 12 g of cerium methacrylate, and 2.5 g of tetramethylguanidine were added into a reaction kettle, nitrogen was introduced, and the mixture was stirred at 80° C. for 4 h to obtain a complexing agent.

[0100] The amino-type ionic liquid is 1-aminoethyl-3-methylimidazole nitrate.

[0101] The preparation method of PA6 is as follows:

[0102] S1: Add caprolactam into the polymerization reactor, raise the temperature to 90°C, and after the caprolactam in the reactor is completely melted, evacuate to -0.08Mpa and stir;

[0103] S2: Add the catalyst, continue to raise the temperature to 100°C, continue to evacuate for 2 hours, and stir;

[0104] S3: Add activator and thermal dispersant, continue to heat to 140°C, stir for 3 hours;

[0105] S4: After the reaction is completed, the material is placed in a container, washed with boiling water three times, each time for 60 minutes, vacuum filtered, and dried to obtain PA6.

[0106] The catalyst is sodium hydroxide.

[0107] The activator is diisocyanate.

[0108] The heat dispersant is kerosene.

[0109] Comparative Example 1

[0110] A method for preparing high-performance polyamide fiber, the operating steps are:

[0111] S1: Weigh 55g solvent and 32g PA6, swell at room temperature under nitrogen protection, dissolve evenly, and degas by centrifugation;

[0112] S2: After passing through a spinneret, a coagulation bath and then winding, a complexed raw fiber is obtained;

[0113] S3: The complexed raw yarn is initially drawn at room temperature and then heat-set to obtain high-performance polyamide fiber.

[0114] The solvent is formic acid.

[0115] The heat setting temperature is 160° C. and the time is 1 minute.

[0116] The preparation method of PA6 is as follows:

[0117] S1: Add caprolactam into the polymerization reactor, raise the temperature to 80°C, and after the caprolactam in the reactor is completely melted, evacuate to -0.06Mpa and stir;

[0118] S2: Add the catalyst, continue to raise the temperature to 90°C, continue to evacuate for 1 hour, and stir;

[0119] S3: Add activator and thermal dispersant, continue to heat to 120°C, stir for 1 hour;

[0120] S4: After the reaction is completed, the material is placed in a container, washed with boiling water three times, each time boiling for 45 minutes, vacuum filtered, and dried to obtain PA6.

[0121] The catalyst is sodium hydroxide.

[0122] The activator is diisocyanate.

[0123] The heat dispersant is kerosene.

[0124] Comparative Example 2

[0125] A method for preparing high-performance polyamide fiber, the operating steps are:

[0126] S1: Weigh 55g solvent, 3g complexing agent, and 32g PA6, swell at room temperature under nitrogen protection, dissolve evenly, and degas by centrifugation;

[0127] S2: After passing through a spinneret, a coagulation bath and then winding, a complexed raw fiber is obtained;

[0128] S3: The complexed raw yarn is initially drawn at room temperature, and then decomplexed and heat-set to obtain high-performance polyamide fiber.

[0129] The solvent is formic acid.

[0130] The decomplexation is performed by placing the complexed raw silk into 30g of ethanol and 40g of water for 3h.

[0131] The heat setting temperature is 160° C. and the time is 1 minute.

[0132] The complexing agent preparation method is:

[0133] 0.05 g of lithium acrylate, 5 g of cerium methacrylate and 0.8 g of tetramethylguanidine were added into a reaction kettle, nitrogen was introduced, and the mixture was stirred at 60° C. for 2 h to obtain a complexing agent.

[0134] The preparation method of PA6 is as follows:

[0135] S1: Add caprolactam into the polymerization reactor, raise the temperature to 80°C, and after the caprolactam in the reactor is completely melted, evacuate to -0.06Mpa and stir;

[0136] S2: Add the catalyst, continue to raise the temperature to 90°C, continue to evacuate for 1 hour, and stir;

[0137] S3: Add activator and thermal dispersant, continue to heat to 120°C, stir for 1 hour;

[0138] S4: After the reaction is completed, the material is placed in a container, washed with boiling water three times, each time boiling for 45 minutes, vacuum filtered, and dried to obtain PA6.

[0139] The catalyst is sodium hydroxide.

[0140] The activator is diisocyanate.

[0141] The heat dispersant is kerosene.

[0142] Comparative Example 3

[0143] A method for preparing high-performance polyamide fiber, the operating steps are:

[0144] S1: Weigh 55g solvent, 3g complexing agent, and 32g PA6, swell at room temperature under nitrogen protection, dissolve evenly, and degas by centrifugation;

[0145] S2: After passing through a spinneret, a coagulation bath and then winding, a complexed raw fiber is obtained;

[0146] S3: The complexed raw yarn is initially drawn at room temperature, and then decomplexed and heat-set to obtain high-performance polyamide fiber.

[0147] The solvent is formic acid.

[0148] The decomplexation is performed by placing the complexed raw silk into 30g of ethanol and 40g of water for 3h.

[0149] The heat setting temperature is 160° C. and the time is 1 minute.

[0150] The complexing agent preparation method is:

[0151] 0.05 g of lithium acrylate, 100 g of amino-type ionic liquid, and 0.8 g of tetramethylguanidine were added into a reaction kettle, nitrogen was introduced, and the reaction mixture was stirred at 60° C. for 2 h to obtain a complexing agent.

[0152] The amino-type ionic liquid is 1-aminopropyl-3-methylimidazole nitrate.

[0153] The preparation method of PA6 is as follows:

[0154] S1: Add caprolactam into the polymerization reactor, raise the temperature to 80°C, and after the caprolactam in the reactor is completely melted, evacuate to -0.06Mpa and stir;

[0155] S2: Add the catalyst, continue to raise the temperature to 90°C, continue to evacuate for 1 hour, and stir;

[0156] S3: Add activator and thermal dispersant, continue to heat to 120°C, stir for 1 hour;

[0157] S4: After the reaction is completed, the material is placed in a container, washed with boiling water three times, each time boiling for 45 minutes, vacuum filtered, and dried to obtain PA6.

[0158] The catalyst is sodium hydroxide.

[0159] The activator is diisocyanate.

[0160] The heat dispersant is kerosene.

[0161] Stretching ratio Breaking strength(GPa) Initial modulus (GPa) Example 1 8 0.47 26.52 Example 2 8 0.49 29.17 Example 3 10 0.53 32.33 Example 4 9 0.51 30.96 Comparative Example 1 3 0.17 15.13 Comparative Example 2 4 0.23 18.63 Comparative Example 3 6 0.31 20.55

Claims

1. A method for preparing high-performance polyamide fiber, the operating steps of which are: S1: According to the mass fractions, weigh 55-80 parts of solvent, 3-7 parts of complexing agent, and 32-38 parts of PA6, swell at room temperature under nitrogen protection, dissolve evenly, and degas by centrifugation; S2: After passing through a spinneret, a coagulation bath and then winding, a complexed raw fiber is obtained; S3: initially drawing the complexed raw silk at room temperature, then decomplexing and heat setting to obtain high-performance polyamide fiber. The complexing agent preparation method is as follows: According to weight, 0.05-0.7 parts of lithium acrylate, 100-120 parts of amino ionic liquid, 5-12 parts of cerium methacrylate, and 0.8-2.5 parts of tetramethylguanidine are added to a reaction kettle, nitrogen is introduced, and the mixture is stirred at 60-80° C. for 2-4 hours to obtain a complexing agent.

2. The method for preparing a high-performance polyamide fiber according to claim 1, characterized in that: The solvent is formic acid, acetone, dichloromethane or chloroform.

3. The method for preparing a high-performance polyamide fiber according to claim 1, characterized in that: The decomplexation is performed by placing the complexed raw silk into 30-45 parts of ethanol and 40-60 parts of water for 3-5 hours.

4. The method for preparing a high-performance polyamide fiber according to claim 1, characterized in that: The heat setting temperature is 160-175° C. and the time is 1-2 minutes.

5. The method for preparing a high-performance polyamide fiber according to claim 1, characterized in that: The amino-type ionic liquid is a mixture of one or more of 1-aminopropyl-3-methylimidazolium nitrate, 1-aminopropyl-3-methylimidazolium tetrafluoroborate, 1-aminopropyl-3-methylimidazolium bromide, and 1-aminoethyl-3-methylimidazolium nitrate in any ratio.

6. The method for preparing a high-performance polyamide fiber according to claim 1, characterized in that: The preparation method of PA6 is as follows: S1: Add caprolactam in the polymerization reactor according to the mass fraction, raise the temperature to 80-90°C, and after the caprolactam in the reactor is completely melted, evacuate to -0.06-0.08Mpa and stir; S2: Add the catalyst, continue to raise the temperature to 90-100°C, continue to evacuate for 1-2 hours, and stir; S3: Add activator and thermal dispersant, continue to heat to 120-140°C, stir for 1-3h; S4: After the reaction is completed, the material is placed in a container, washed with boiling water three times, each time boiling for 45-60 minutes, vacuum filtered, and dried to obtain PA6.

7. The method for preparing a high-performance polyamide fiber according to claim 6, characterized in that: The catalyst is sodium hydroxide.

8. The method for preparing a high-performance polyamide fiber according to claim 6, characterized in that: The activator is diisocyanate.

9. The method for preparing a high-performance polyamide fiber according to claim 6, characterized in that: The heat dispersant is kerosene.