A kind of preparation method of ternary copolymerization polyimide fiber

Abstract

The present invention relates to a preparation method of a terpolymerized polyimide fiber of the present invention, comprising: (1) benzophenone tetraacid dianhydride, diisocyanate, NaOH aqueous solution and Mix solvents and react in a nitrogen atmosphere at 60-90°C to obtain ternary copolymerization polyimide slurry; (2) Filter the above ternary copolymerization polyimide solution and vacuum defoam, then use wet method fiber molding process to obtain ternary copolymerized polyimide primary fibers; (3) heat-treat and heat-stretch the above-mentioned ternary copolymerized polyimide primary fibers. The process of the present invention is mature, simple and flexible in operation, low in cost, and very beneficial to industrial production; the ternary copolymerized polyimide fiber prepared in the present invention has excellent mechanical properties, thermal properties and flame-retardant properties, and can be used at temperatures above 300°C Long-term use at high temperature.

Description

technical field

[0001] The invention belongs to the field of preparation of polyimide fibers, in particular to a preparation method of terpolymerized polyimide fibers. Background technique

[0002] Aromatic polyimide fibers have excellent properties such as high temperature resistance, flame retardancy, radiation resistance, high strength, high modulus, and chemical corrosion resistance, and are widely used in high-tech fields such as aviation, aerospace, and microelectronics. The preparation methods of ternary copolymerized polyimide fibers mainly include the following types: (1) melting method, the polyamic acid obtained by polycondensation is precipitated in water or ethanol solvent, and thermally imidized to obtain copolymerized polyimide Powder, and then melt spinning, that is. It is described in detail in patents US5840828, US5670256, W9800590 and JP2000129535. However, the molecular weight of the copolymerized polyimide resin is not high, and the obtained copolymeri...

Examples

Embodiment 1

[0029] At the beginning of polymerization, it is first necessary to ensure that the humidity of the environment where the polymerization system is located is lower than 40%. Weigh 0.5mol (about 161g) of benzophenone tetraacid dianhydride (ketone anhydride) and 597g of N,N-dimethylacetamide (DMAc) into a 1000ml four-necked flask equipped with a stirring device and a nitrogen inlet , and then add 0.3 grams of NaOH solid solution (NaOH: water mass ratio = 1:1) as a catalyst, 60 grams of solubilizer (anhydrous LiCl or CaCl 2 ). Under the action of continuous stirring, heat the reaction system to 80°C, then add 0.5mol diisocyanate mixture (0.4mol toluene diisocyanate + 0.1mol biphenyl diisocyanate) dropwise into the reaction system, wait for the diisocyanate to drop After the addition is complete, continue the reaction until there is no CO 2 until the gas is generated. A viscous liquid with a solid content of about 30% and a reduced viscosity of 0.75 dL / g (measured at 30°C with ...

Embodiment 2-6

[0031] The reaction process is the same as in Example 1, and the other conditions are shown in Table 1.

[0032] Table 1: Polymerization conditions for Examples 2-6

[0033]

[0034] Note: The solvent DMAc in Table 1 is N,N-dimethylacetamide; DMF is N,N-dimethylformamide; NMP is N-methylpyrrolidone; the diisocyanate molar ratio is toluene diisocyanate to biphenyl The molar ratio of diisocyanate.

Embodiment 7

[0036] The polyimide solution obtained in Example 1 was spun and shaped by wet process technology. Fill the storage tank with spinneret with about 500ml of spinning slurry, and keep the temperature of the storage tank at 30-80°C by using the circulating water passing into the jacket, and the absolute vacuum degree is 1×10 -3 MPa~50×10 -3Stand for defoaming under MPa for 2 to 4 days, and then spinning can be carried out. The diameter of the spinneret hole is 0.08 mm, the aspect ratio (L / D) of the spinneret hole is 10, the temperature of the coagulation bath is 25 °C, and the composition of the coagulation bath is DMAc / water (70 / 30 mass ratio). The negative stretch of the nozzle is -30%, the water bath is tap water, the temperature is 70-90°C, and the draft ratio is 1.2. Nitrogen is used to apply a pressure of 0.3 MPa to 0.5 MPa to the spinning slurry, and the spinning slurry passes through a 1000-mesh filter cloth to obtain terpolymerized polyimide primary fibers. The as-spu...

technical field

[0001] The invention belongs to the field of preparation of polyimide fibers, in particular to a preparation method of terpolymerized polyimide fibers. Background technique

[0002] Aromatic polyimide fibers have excellent properties such as high temperature resistance, flame retardancy, radiation resistance, high strength, high modulus, and chemical corrosion resistance, and are widely used in high-tech fields such as aviation, aerospace, and microelectronics. The preparation methods of ternary copolymerized polyimide fibers mainly include the following types: (1) melting method, the polyamic acid obtained by polycondensation is precipitated in water or ethanol solvent, and thermally imidized to obtain copolymerized polyimide Powder, and then melt spinning, that is. It is described in detail in patents US5840828, US5670256, W9800590 and JP2000129535. However, the molecular weight of the copolymerized polyimide resin is not high, and the obtained copolymeri...

Examples

Embodiment 1

[0029] At the beginning of polymerization, it is first necessary to ensure that the humidity of the environment where the polymerization system is located is lower than 40%. Weigh 0.5mol (about 161g) of benzophenone tetraacid dianhydride (ketone anhydride) and 597g of N,N-dimethylacetamide (DMAc) into a 1000ml four-necked flask equipped with a stirring device and a nitrogen inlet , and then add 0.3 grams of NaOH solid solution (NaOH: water mass ratio = 1:1) as a catalyst, 60 grams of solubilizer (anhydrous LiCl or CaCl 2 ). Under the action of continuous stirring, heat the reaction system to 80°C, then add 0.5mol diisocyanate mixture (0.4mol toluene diisocyanate + 0.1mol biphenyl diisocyanate) dropwise into the reaction system, wait for the diisocyanate to drop After the addition is complete, continue the reaction until there is no CO 2 until the gas is generated. A viscous liquid with a solid content of about 30% and a reduced viscosity of 0.75 dL / g (measured at 30°C with ...

Embodiment 2-6

[0031] The reaction process is the same as in Example 1, and the other conditions are shown in Table 1.

[0032] Table 1: Polymerization conditions for Examples 2-6

[0033]

[0034] Note: The solvent DMAc in Table 1 is N,N-dimethylacetamide; DMF is N,N-dimethylformamide; NMP is N-methylpyrrolidone; the diisocyanate molar ratio is toluene diisocyanate to biphenyl The molar ratio of diisocyanate.

Embodiment 7

[0036] The polyimide solution obtained in Example 1 was spun and shaped by wet process technology. Fill the storage tank with spinneret with about 500ml of spinning slurry, and keep the temperature of the storage tank at 30-80°C by using the circulating water passing into the jacket, and the absolute vacuum degree is 1×10 -3 MPa~50×10 -3Stand for defoaming under MPa for 2 to 4 days, and then spinning can be carried out. The diameter of the spinneret hole is 0.08 mm, the aspect ratio (L / D) of the spinneret hole is 10, the temperature of the coagulation bath is 25 °C, and the composition of the coagulation bath is DMAc / water (70 / 30 mass ratio). The negative stretch of the nozzle is -30%, the water bath is tap water, the temperature is 70-90°C, and the draft ratio is 1.2. Nitrogen is used to apply a pressure of 0.3 MPa to 0.5 MPa to the spinning slurry, and the spinning slurry passes through a 1000-mesh filter cloth to obtain terpolymerized polyimide primary fibers. The as-spu...

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