CN117264197A - Continuous production method and device for high-temperature-resistant nylon - Google Patents

Abstract

The invention relates to the field of high polymer material synthesis, and provides a continuous production method of high temperature resistant nylon, which aims at the problems of poor hue and poor uniformity of copolymerized nylon prepared by high temperature polymerization, and comprises the following steps of (1) mixing dibasic acid, diamine, lactam, a reaction auxiliary agent and water, and carrying out salt formation reaction to obtain nylon salt solution; 2, carrying out a prepolymerization reaction on the nylon salt solution in a tubular polymerization reactor, and drying after the reaction to obtain a powdery prepolymer; 3, carrying out primary polycondensation on the powdery prepolymer in a primary polycondensation device, and then carrying out secondary polycondensation in a secondary polycondensation device to obtain powdery high-temperature-resistant nylon; the reaction temperature of the prepolymerization and the polycondensation is 200-250 ℃, the polycondensation stage is carried out below the melting point of the materials, and the second-stage polycondensation temperature is higher than the first-stage polycondensation. The reaction temperature of the whole polymerization pipeline is relatively close to and lower than 250 ℃, so that the uniformity and the hue of the copolymerization component can be greatly improved. The invention also provides a device matched with the production method.

Description

A kind of high temperature resistant nylon continuous production method and device

Technical field

The invention relates to the field of polymer material synthesis, and in particular to a high-temperature resistant nylon continuous production method and device.

Background technique

High temperature resistant nylon has the advantages of high strength, solvent resistance, wear resistance, and easy processing and molding. As an important engineering plastic, it is widely used in automotive parts, electronic appliances, engineering parts and other fields. Traditional high-temperature resistant nylon production uses a batch kettle melt polymerization method (such as patent CN105330846A). This method is very easy to produce residual materials in the kettle, and too much transition material is produced when changing varieties, seriously affecting product quality, and the production efficiency is low. Different batches There is a big difference in product performance between them.

Invention patent CN115873236A provides a method for preparing high-temperature resistant nylon through continuous polymerization. However, the reaction temperature in the polycondensation stage of this method is high, and through screw extrusion, the equipment cost is high, the production capacity is limited, and the product hue is easily affected by adverse effects at high temperatures. Invention patent CN113698288A discloses the use of nylon salt solid-state polymerization to produce high-temperature-resistant nylon, which can effectively solve problems such as residues in high-viscosity melt reactors and oxidation at high temperatures that affect product quality. However, this method of using nylon salt solid-state polymerization has a negative impact on PA6T /6, PA6T/66 and other types of nylon copolymerized with low melting point monomers have certain effects. It is difficult to achieve uniform mixing of the two nylon salts at the molecular level. Moreover, due to the large difference in the melting points of the two nylon salt raw materials, it is easy to Phase separation occurs during the heating process, which affects the uniformity and comprehensive performance of the final copolymer product. An ideal solution is therefore required.

Contents of the invention

In order to overcome the problems of poor hue and poor uniformity of copolymerized nylon prepared by high-temperature polymerization, the present invention provides a high-temperature resistant nylon continuous production method, which includes the following steps: (1) Salt formation: combining dibasic acid, diamine, Lactam, reaction aid and water are mixed, and a nylon salt solution is obtained through a salt-forming reaction;

(2) Ring-opening prepolymerization: The nylon salt solution is prepolymerized in a tubular polymerization reactor, and dried after the reaction to obtain a powdery prepolymer;

(3) Solid phase polycondensation: The powder prepolymer is first subjected to primary polycondensation in a primary condensation polymerizer, and then secondary polycondensation is performed in a secondary condensation polymerizer to obtain powdered high-temperature resistant nylon;

The reaction temperatures of the prepolymerization reaction in step (2) and the primary polycondensation and secondary polycondensation in step (3) are 200-250°C. The polycondensation stages are all performed below the melting point of the material, and the secondary polycondensation temperature is higher than the primary polycondensation.

The polycondensation stage of the present invention is carried out below the melting point of the material, and the material is not prone to adhesion. It solves the problem of the long-term high-temperature oxidation of the residual material on the color of the product and the problem of excessive transition materials between different batches, and facilitates real-time online adjustment and formula replacement. Variety, reducing the production of transition materials, low start-up costs. The reaction temperatures of the entire polymerization (including prepolymerization and polycondensation) pipelines are relatively close, and there is no need for a higher heat media system, which can significantly reduce energy consumption and reduce equipment requirements.

Preferably, the temperature of the prepolymerization reaction in step (2) is 210-250°C, the reaction temperature of the primary polycondensation in step (3) is 200-230°C, and the reaction temperature of the second-level polycondensation is 230-250°C.

Preferably, the high-temperature resistant nylon obtained in step (3) is PA6T/6, PA5T/6, or PA6T/66. When using solid-state polymerization of nylon salts to prepare this type of nylon copolymerized with low-melting point monomers, it is difficult to achieve uniform mixing of the two nylon salts at the molecular level. Moreover, due to the large difference in the melting points of the two nylon salt raw materials, it is easy to occur during the heating process. Phase separation affects the uniformity and comprehensive properties of the final copolymer product. The prepolymerization stage of the present invention is carried out in a tubular polymerization reactor, which can greatly improve the uniformity of copolymer components, ensure the uniformity and stability of product quality, and is conducive to improving the ring-opening/prepolymerization reaction efficiency under high temperature and high pressure, and reducing reaction time.

Preferably, the high-temperature resistant nylon obtained in step (3) is PA5T. PA5T is a bio-based high-temperature resistant nylon that is prone to side reactions during the polymerization process because pentanediamine cyclizes at high temperatures (>250°C) to form piperidine, and then piperidine and terephthalic acid condense to form terephthalic acid. Dipiperidine, and finally it is further oxidized to form a new carbonyl structure - di(2-carbonyl substituted piperidine) terephthalate on the α-methylene group next to the amine group. The existence of this α-ketoamide group Causes the product to turn yellow. As the residence time of the polymerization reaction at high temperature is prolonged, more bis(2-carbonyl-substituted piperidine) terephthalate is produced, and the color of PA5T will gradually become darker. In addition, the molar ratio of dibasic acid and diamine monomers is unbalanced, and the condensation of piperidine and active oligomers leads to the deactivation of the polyamide growing chain, which makes it difficult to increase the molecular weight of the polymer. Moreover, since pentanediamine is easily cyclized to form a stable six-membered ring structure - piperidine, its thermal degradation mechanism is mainly based on the amide bond cleavage reaction pathway. There are also piperidine and piperidine derivatives in the pyrolysis products, which affects the color of the product. quality. The reaction temperatures of the entire polymerization (including prepolymerization and polycondensation) pipelines of the present invention are relatively close and lower than 250°C, which can avoid side reactions of pentanediamine during the production process and obtain PA5T with good performance.

Preferably, the mixing conditions in step (1) are stirring at 50-70°C for 1-3 hours.

Preferably, the conditions for the salt-forming reaction in step (1) are 120-160°C and 0.5-1.5MPa for 1-2 hours. The present invention adopts high temperature and high pressure to form salt, which improves the reaction efficiency, eliminates the need for concentration process and reduces energy consumption.

Preferably, the temperature of the prepolymerization reaction in step (2) is 220-250°C, the pressure is 1.5-2.5MPa, and the reaction time is 3-8 hours. The salt formation and prepolymerization stages of the present invention are both solution systems, with low viscosity and difficulty in residues.

Preferably, the product of the prepolymerization reaction in step (2) is sprayed into the drying tower under a pressure of 1.0-2.0MPa, and then separated through a cyclone separator to obtain a powdery prepolymer.

Preferably, the reaction pressure of the first-stage polycondensation in step (3) is an absolute pressure of 1000-500 mbar, and the reaction time is 1-6 h. The first-level polycondensation stage of the present invention is carried out under solid materials, which reduces adhesion residues, reduces oxidation, and improves product quality.

Preferably, the reaction pressure of the secondary polycondensation in step (3) is absolute pressure ≤ 1 mbar, and the reaction time is 2-6 h.

Preferably, the entire production process is operated under the protection of nitrogen or inert gas, and materials are also transported through nitrogen or inert gas. Ensure that materials are not easily oxidized at high temperatures and ensure product quality.

The invention also provides a high-temperature resistant nylon continuous production device, which is a supporting device for the above-mentioned production method, including a mixing tank, a salt-forming kettle, a storage tank, an open-loop prepolymerization kettle, a drying tower, a cyclone separator and a Condensation polymerization system, the ring-opening prepolymerization tank is a tubular polymerization reactor.

Preferably, the polycondensation system includes a storage tank, a primary condensation unit, a buffer tank, a secondary condensation unit and a finished product tank connected in sequence, and the cyclone separator is connected to the storage tank.

Therefore, the beneficial effects of the present invention are: (1) The reaction temperature of the entire polymerization pipeline is not higher than 250°C, which can effectively avoid the side reaction of the bio-based monomer pentanediamine; (2) The salt is formed using high temperature and high pressure. Improve reaction efficiency, eliminate the need for concentration process, and reduce energy consumption; (3) The prepolymerization stage is carried out in a tubular polymerization reactor, which can greatly improve the uniformity of copolymerization components, ensure uniformity and stability of product quality, and high temperature Under high pressure, it is beneficial to improve the ring-opening/prepolymerization reaction efficiency and reduce the reaction time; (4) the salt formation/prepolymerization stage is a solution system with low viscosity and is not easy to remain; (5) the first-level polycondensation stage is carried out under solid materials, Reduce adhesion residue, reduce oxidation, and improve product quality; (6) The polycondensation stage is carried out below the melting point of the material, and the material is not prone to adhesion. This solves the impact of long-term high-temperature oxidation of the residual material on the color of the product and the transition of materials between different batches. Many problems can be solved, which facilitates real-time online adjustment of formula and replacement varieties, reduces the generation of transition materials, and lowers start-up costs; (7) The reaction temperature of the entire polymerization pipeline is relatively close, and there is no need for a higher heat media system, which can significantly reduce energy consumption and reduce the impact on equipment. Requirements; (8) The entire polymerization pipeline and container are operated under the protection of inert gas, and the materials are also transported through inert gas to ensure that the materials are not easily oxidized at high temperatures and ensure product quality.

Description of the drawings

Figure 1 is a schematic diagram of the device of the present invention.

In the picture, 1. Mixing tank, 2. Salt-forming kettle, 3. Storage tank, 4. Tubular polymerization reactor, 5. Drying tower, 6. Cyclone separator, 7. Storage tank, 8. First-level polycondensation device, 9. Buffer tank, 10. Secondary condensation polymerizer, 11. Finished product tank.

Detailed ways

The technical solution of the present invention will be further described below through specific examples.

In the present invention, unless otherwise specified, the raw materials and equipment used can be purchased from the market or are commonly used in the art. The methods in the examples, unless otherwise specified, are all conventional methods in the art.

General embodiment

A continuous production method of high temperature resistant nylon, including the following steps:

(1) Salt formation: Add dibasic acid, diamine, lactam, reaction aid and deionized water into the mixing tank, mix and transfer to the salt-forming kettle to react to obtain a nylon salt solution. The reaction conditions are 120- React at 160℃, 0.5-1.5MPa for 1-2h.

(2) Ring-opening prepolymerization: The nylon salt solution is prepolymerized in a ring-opening prepolymerization kettle to ring-open the lactam and prepolymerize the nylon salt. The reaction conditions are 210-250°C and 1.5-2.5MPa. Reaction 3 -8h; after the reaction, it is sprayed into the drying tower under a pressure of 1.0-2.0MPa, and separated through a cyclone separator to obtain a powdery prepolymer.

(3) Solid phase polycondensation: The powder prepolymer is first transported to the first-level polycondensation vessel through nitrogen or inert gas for preliminary viscosity increase. The absolute pressure is controlled to 900-500mbar, the reaction temperature is 200-230°C, and the residence time is 1-6h. ; Then it enters the secondary condensation polymerizer through the buffer tank to obtain powdered high-temperature resistant nylon. The absolute pressure is controlled within 1 mbar, the reaction temperature is 230-250°C, and the residence time is 2-6 hours.

Preferably, the present invention also provides the above-mentioned high-temperature resistant nylon continuous production device, as shown in Figure 1, including a mixing tank, a salt-forming kettle, a storage tank, an open-loop prepolymerization kettle, a drying tower, a cyclone separator and a A polycondensation system includes a storage tank, a primary condensation unit, a buffer tank, a secondary condensation unit and a finished product tank connected in sequence, and the cyclone separator is connected to the storage tank. The ring-opening prepolymerization tank is a tubular polymerization reactor.

Example 1

A high-temperature resistant nylon continuous production device is shown in Figure 1, which consists of a mixing tank 1, a salt-forming kettle 2, a storage tank 3, a tubular polymerization reactor 4, a drying tower 5, a cyclone separator 6, and a storage tank connected in sequence. Material tank 7, primary condensation unit 8, buffer tank 9, secondary condensation unit 10 and finished product tank 11.

A continuous production method of high temperature resistant nylon PA6T/6, the steps are:

(1) Salt formation: Add 249.20kg terephthalic acid, 174.30kg hexamethylenediamine, 113.16kg caprolactam, 1.2kg phosphoric acid catalyst and 200kg desalted water into mixing tank 1, raise the temperature to 60°C, continue stirring for 1 hour, and transfer to In the salt-forming kettle 2, the temperature is raised to 150°C, the pressure is controlled to 0.5MPa, and the reaction is carried out for 1 hour to obtain the PA6T/6 salt solution, which is transferred to the storage tank 3 for storage.

(2) Ring-opening prepolymerization: The nylon salt solution is prepolymerized in a ring-opening prepolymerization tank, that is, the tubular polymerization reactor 4, to ring-open the lactam and prepolymerize the nylon salt. The reaction conditions are 220°C (upper end temperature) and 1.5 MPa for 5 hours; after the reaction, it is sprayed into the drying tower 5 under a pressure of 1.0 MPa, separated by the cyclone separator 6 to obtain the dry powdery prepolymer, and transferred to the storage tank 7 for storage.

(3) Solid-phase polycondensation: The powder prepolymer is first transported to the first-stage polycondensation vessel 8 through nitrogen for preliminary viscosity increase. The control pressure is a slightly negative pressure state, with an absolute pressure of 800 mbar, a reaction temperature of 230°C, and a residence time of 2 hours; Then it enters the secondary condensation polymerizer 10 through the buffer tank 9, controls the absolute pressure to 0.5 mbar, the reaction temperature to 250°C, and the residence time to 3 hours to obtain powdered high-temperature resistant nylon PA6T/6, which is transferred to the finished product tank 11 for storage.

Example 2

The difference from Example 1 is that the residence time in the secondary polycondensation vessel in step (3) is 6 hours.

Example 3

A continuous production method of high temperature resistant nylon PA5T/6, the steps are:

(1) Salt formation: Add 249.20kg terephthalic acid, 153.27kg pentanediamine, 113.16kg caprolactam, 1.15kg phosphoric acid catalyst and 200kg desalted water into mixing tank 1, raise the temperature to 60°C, continue stirring for 1 hour, and transfer to In the salt-forming kettle 2, the temperature is raised to 150°C, the pressure is controlled to 0.5MPa, and the reaction is carried out for 1 hour to obtain the PA5T/6 salt solution, which is transferred to the storage tank 3 for storage.

(2) Ring-opening prepolymerization: The nylon salt solution is prepolymerized in a ring-opening prepolymerization tank, that is, the tubular polymerization reactor 4, to ring-open the lactam and prepolymerize the nylon salt. The reaction conditions are 220°C (upper end temperature) and 1.5 MPa for 5 hours; after the reaction, it is sprayed into the drying tower 5 under a pressure of 1.0 MPa, separated by the cyclone separator 6 to obtain the dry powdery prepolymer, and transferred to the storage tank 7 for storage.

(3) Solid-phase polycondensation: The powder prepolymer is first transported to the first-stage polycondensation vessel 8 through nitrogen for preliminary viscosity increase, and the pressure is controlled to a slightly negative pressure state, with an absolute pressure of 800 mbar, a reaction temperature of 220°C, and a residence time of 2 hours; Then it enters the secondary condensation polymerizer 10 through the buffer tank 9, controls the absolute pressure to 0.5 mbar, the reaction temperature to 250°C, and the residence time to 3 hours to obtain powdered high-temperature resistant nylon PA5T/6, which is transferred to the finished product tank 11 for storage.

Example 4

The difference from Example 3 is that the residence time in the secondary polycondensation vessel in step (3) is 6 hours.

Example 5

A continuous production method of high temperature resistant nylon PA6T/66, the steps are:

(1) Salt formation: Add 249.20kg terephthalic acid, 146.10kg adipic acid, 290.50kg hexamethylenediamine, 1.5kg phosphoric acid catalyst and 270kg desalted water into mixing tank 1, raise the temperature to 60°C, and continue stirring for 1 hour. Transfer to the salt-forming kettle 2, raise the temperature to 150°C, control the pressure to 0.5MPa, and react for 1 hour to obtain the PA6T/66 salt solution, which is transferred to the storage tank 3 for storage.

(2) Ring-opening prepolymerization: The nylon salt solution is prepolymerized in a ring-opening prepolymerization tank, that is, the tubular polymerization reactor 4, to ring-open the lactam and prepolymerize the nylon salt. The reaction conditions are 220°C (upper end temperature) and 1.5 MPa for 5 hours; after the reaction, it is sprayed into the drying tower 5 under a pressure of 1.0 MPa, separated by the cyclone separator 6 to obtain the dry powdery prepolymer, and transferred to the storage tank 7 for storage.

(3) Solid-phase polycondensation: The powder prepolymer is first transported to the first-stage polycondensation vessel 8 through nitrogen for preliminary viscosity increase. The control pressure is a slightly negative pressure state, with an absolute pressure of 800 mbar, a reaction temperature of 230°C, and a residence time of 2 hours; Then it enters the secondary condensation polymerizer 10 through the buffer tank 9, controls the absolute pressure to 0.5 mbar, the reaction temperature to 250°C, and the residence time to 3 hours to obtain powdered high-temperature resistant nylon PA6T/66, which is transferred to the finished product tank 11 for storage.

Example 6

The difference from Example 5 is that the residence time in the secondary polycondensation vessel in step (3) is 6 hours.

Example 7

A continuous production method of high temperature resistant nylon PA10T, the steps are:

(1) Salt formation: Add 249.20kg terephthalic acid, 258.46kg decanediamine, 1.2kg phosphoric acid catalyst and 300kg desalted water into the mixing tank 1, raise the temperature to 60°C, continue stirring for 1 hour, and transfer to the salt formation kettle 2 , raise the temperature to 150°C, control the pressure to 0.5MPa, and react for 1 hour to obtain the PA10T salt solution, which is transferred to storage tank 3 for storage.

(2) Ring-opening prepolymerization: The nylon salt solution is prepolymerized in a ring-opening prepolymerization tank, that is, the tubular polymerization reactor 4, to ring-open the lactam and prepolymerize the nylon salt. The reaction conditions are 220°C (upper end temperature) and 1.5 MPa for 5 hours; after the reaction, it is sprayed into the drying tower 5 under a pressure of 1.0 MPa, separated by the cyclone separator 6 to obtain the dry powdery prepolymer, and transferred to the storage tank 7 for storage.

(3) Solid-phase polycondensation: The powder prepolymer is first transported to the first-stage polycondensation vessel 8 through nitrogen for preliminary viscosity increase, and the pressure is controlled to a slightly negative pressure state, with an absolute pressure of 800 mbar, a reaction temperature of 220°C, and a residence time of 3 hours; Then it enters the secondary condensation polymerizer 10 through the buffer tank 9, controls the absolute pressure to 0.5 mbar, the reaction temperature to 250°C, and the residence time to 4 hours to obtain powdered high-temperature resistant nylon PA10T, which is transferred to the finished product tank 11 for storage.

Example 8

The difference from Example 7 is that the residence time in the secondary polycondensation vessel in step (3) is 7 hours.

Comparative example 1

A continuous production method of high-temperature resistant nylon PA6T/6. The difference from Example 1 is that the method described in patent CN112979941A is adopted.

Comparative example 2

A continuous production method of high-temperature resistant nylon PA5T/6. The difference from Example 3 is that the method described in patent CN112979941A is adopted.

Comparative example 3

A continuous production method of high-temperature resistant nylon PA6T/66. The difference from Example 5 is that PA6T/66 is prepared using the method described in patent CN112979941A. The types and amounts of raw materials are the same as those in Example 5.

Comparative example 4

A continuous production method of high-temperature resistant nylon PA10T. The difference from Example 7 is that the method described in patent CN112979941A is adopted.

Comparative example 5

A continuous production method of high-temperature resistant nylon PA5T/6. The difference from Example 3 is that the method described in patent CN105330846A is adopted.

Performance Testing

Perform performance tests on the products of the above embodiments and comparative examples. The test equipment and test standards used are:

The characterization results are shown in the table below.

As can be seen from the above table, the present invention is suitable for the production of various types of high-temperature resistant nylon, especially bio-based high-temperature resistant nylon PA5T. The product has excellent thermal and mechanical properties, and its relative viscosity can be controlled by the reaction time. Comparative Examples 1, 2, and 3 used patent CN112979941A to prepare PA6T/6, PA5T/6, and PA6T/66. High-temperature resistant nylon prepared by caprolactam copolymerization showed multiple melting peaks, and its mechanical strength was significantly lower than that of Examples 1 and 3. , 5, indicating that it is difficult to achieve uniform mixing and copolymerization of the two components by the method described in the comparative example, and obvious inhomogeneity occurs, while the high-temperature resistant nylon prepared by the method of the present invention has a single melting point and good uniformity. , the performance is even better. The performance of Comparative Example 4 and Example 7 are basically consistent, indicating that both inventive methods can be applied to the production of single-component high-temperature resistant nylon. The bio-based high-temperature resistant nylon PA5T prepared by the method in Examples 3 and 4 has good hue and high relative viscosity, and can meet the needs of subsequent use, because the present invention controls the entire reaction process so that the reaction temperature in the polymerization pipeline is not higher than 250°C. PA5T can be produced under the conditions, effectively avoiding the side reaction of the bio-based monomer pentanediamine; Comparative Example 5 uses the existing technology to produce PA5T, which has a different color, low relative viscosity of the product, and its performance is far inferior to that of the present invention.

The above are only preferred embodiments of the present invention and are not intended to limit the present invention in any form. Although the present invention has been disclosed above in preferred embodiments, they are not intended to limit the present invention. Anyone familiar with this field will Skilled persons, without departing from the scope of the technical solution of the present invention, can use the technical content disclosed above to make some changes or modifications to equivalent embodiments with equivalent changes. Technical Essence Any simple modifications, equivalent changes and modifications made to the above embodiments still fall within the scope of the technical solution of the present invention.

Claims (10)

1. The continuous production method of the high-temperature-resistant nylon is characterized by comprising the following steps of:

(1) Salt formation: mixing dibasic acid, diamine, lactam, reaction auxiliary agent and water, and carrying out salt forming reaction to obtain nylon salt solution;

(2) Ring opening prepolymerization: the nylon salt solution is subjected to prepolymerization reaction in a tubular polymerization reactor, and is dried after the reaction to obtain powdery prepolymer;

(3) Solid phase polycondensation: the powder prepolymer is subjected to primary polycondensation in a primary polycondensation device, and then is subjected to secondary polycondensation in a secondary polycondensation device, so that powdery high-temperature resistant nylon is obtained;

the temperature of the prepolymerization reaction in the step (2) and the reaction temperature of the first-stage polycondensation in the step (3) are 200-250 ℃, the polycondensation stage is carried out below the melting point of the material, and the second-stage polycondensation temperature is higher than the first-stage polycondensation.

2. The continuous production method of high-temperature-resistant nylon according to claim 1, wherein the temperature of the prepolymerization reaction in the step (2) is 210-250 ℃, the reaction temperature of the first-stage polycondensation in the step (3) is 200-230 ℃, and the reaction temperature of the second-stage polycondensation is 230-250 ℃.

3. The continuous production method of high-temperature-resistant nylon according to claim 1 or 2, wherein the high-temperature-resistant nylon obtained in the step (3) is PA6T/6, PA5T/6 or PA6T/66.

4. The continuous production method of high-temperature-resistant nylon according to claim 1 or 2, wherein the high-temperature-resistant nylon obtained in the step (3) is PA5T.

5. The continuous production method of high-temperature-resistant nylon according to claim 1, wherein the salt forming reaction condition of the step (1) is 120-160 ℃ and 0.5-1.5MPa for 1-2h.

6. The continuous production method of high-temperature-resistant nylon according to claim 2, wherein the temperature of the prepolymerization reaction in the step (2) is 220-250 ℃, the pressure is 1.5-2.5MPa, and the reaction time is 3-8h.

7. The continuous production method of high-temperature-resistant nylon according to claim 1, wherein the reaction pressure of the first-stage polycondensation in the step (3) is 1000-500mbar absolute pressure, and the reaction time is 1-6h.

8. The continuous production method of high-temperature-resistant nylon according to claim 1 or 7, wherein the reaction pressure of the secondary polycondensation in the step (3) is less than or equal to 1mbar absolute pressure, and the reaction time is 2-6h.

9. The apparatus for use in the production process according to any one of claims 1 to 8, comprising a mixing tank, a salifying kettle, a storage tank, an open-loop prepolymerization kettle, a drying tower, a cyclone separator and a polycondensation system which are connected in this order, wherein the open-loop prepolymerization kettle is a tubular polymerization reactor.

10. The apparatus of claim 9, wherein the polycondensation system comprises a storage tank, a primary polycondenser, a buffer tank, a secondary polycondenser, and a finishing tank connected in sequence, and wherein the cyclone is connected to the storage tank.