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

Abstract

The present invention relates to the field of polymer material synthesis. Aiming at the problem that nylon prepared by high temperature polymerization has poor hue and poor uniformity of copolymerized nylon, a continuous production method of high temperature resistant nylon is provided, comprising the steps of 1 mixing dibasic acid, diamine, lactam, reaction aid and water, and performing salt-forming reaction to obtain nylon salt solution; 2 the nylon salt solution is subjected to prepolymerization reaction in a tubular polymerization reactor, and dried after the reaction to obtain a powdered prepolymer; 3 the powdered prepolymer is first subjected to primary polycondensation in a primary polycondenser, and then to secondary polycondensation in a secondary polycondenser to obtain powdered high temperature resistant nylon; the reaction temperature of prepolymerization and polycondensation is 200-250°C, the polycondensation stage is carried out below the melting point of the material, and the secondary polycondensation temperature is higher than the primary polycondensation. The reaction temperature of the entire polymerization pipeline of the present invention is close to and lower than 250°C, which can greatly improve the uniformity and hue of the copolymer components. The present invention also provides a device supporting the above production method.

Description

Technical Field

[0001] The invention relates to the field of polymer material synthesis, and in particular to a continuous production method and device for high temperature resistant nylon. Background Art

[0002] 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 the fields of automotive parts, electronic appliances, and engineering parts. The traditional production of high temperature resistant nylon adopts the intermittent reactor melt polymerization method (such as patent CN105330846A). This method is very easy to produce residual materials in the reactor, and excessive transition materials are produced when changing varieties, which seriously affects the product quality. In addition, the production efficiency is low, and the product performance varies greatly between different batches.

[0003] Invention patent CN115873236A provides a method for preparing high temperature resistant nylon by continuous polymerization, but the reaction temperature in the polycondensation stage of this method is high, and the equipment cost is high and the production capacity is limited by screw extrusion, and the product color is easily affected at high temperature. Invention patent CN113698288A discloses the use of nylon salt solid phase polymerization to produce high temperature resistant nylon, which can effectively solve the problems of residue in the high viscosity melt reactor and oxidation at high temperature affecting product quality. However, this method of using nylon salt solid phase polymerization has a certain impact on the preparation of nylon copolymerized with low melting point monomers such as PA6T / 6 and PA6T / 66. It is difficult to achieve uniform mixing of the two nylon salts at the molecular level, and due to the large difference in the melting points of the two nylon salt raw materials, phase separation is easy to occur during the heating process, affecting the uniformity and comprehensive performance of the final copolymer product. Therefore, an ideal solution is needed. Summary of the invention

[0004] In order to overcome the problems of poor hue of nylon prepared by high temperature polymerization and poor uniformity of copolymerized nylon, the present invention provides a continuous production method of high temperature resistant nylon, comprising the following steps: (1) salt formation: mixing a dibasic acid, a diamine, a lactam, a reaction aid and water, and performing a salt formation reaction to obtain a nylon salt solution;

[0005] (2) Ring-opening prepolymerization: the nylon salt solution is subjected to a prepolymerization reaction in a tubular polymerization reactor, and dried after the reaction to obtain a powdered prepolymer;

[0006] (3) solid phase polycondensation: the powder prepolymer is first subjected to primary polycondensation in a primary polycondensation vessel, and then subjected to secondary polycondensation in a secondary polycondensation vessel to obtain powdered high temperature resistant nylon;

[0007] The temperature of the prepolymerization reaction in step (2) and the reaction temperature of the primary polycondensation and the secondary polycondensation in step (3) are 200-250° C. The polycondensation stages are all carried out below the melting point of the materials, and the secondary polycondensation temperature is higher than the primary polycondensation temperature.

[0008] The polycondensation stage of the present invention is carried out below the melting point of the material, the material is not easy to stick together, and the influence of the residual material on the product color due to long-term high-temperature oxidation and the problem of excessive transition materials between different batches are solved. It is convenient to adjust the formula and change the variety online in real time, reduce the generation of transition materials, and reduce the start-up cost. The reaction temperature of the entire polymerization (including prepolymerization and polycondensation) pipeline is relatively close, and no high heat medium system is required, which can greatly reduce energy consumption and reduce the requirements for equipment.

[0009] Preferably, the temperature of the prepolymerization reaction in step (2) is 210-250°C, the temperature of the primary polycondensation reaction in step (3) is 200-230°C, and the temperature of the secondary polycondensation reaction is 230-250°C.

[0010] Preferably, the high temperature resistant nylon obtained in step (3) is PA6T / 6, PA5T / 6, and PA6T / 66. It is difficult to achieve uniform mixing of the two nylon salts at the molecular level by solid phase polymerization of nylon salts to prepare such nylons copolymerized with low melting point monomers. In addition, due to the large difference in melting points of the two nylon salt raw materials, phase separation is likely to occur during the heating process, affecting the uniformity and comprehensive performance 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 the copolymer components, ensure the uniformity and stability of the product quality, and is conducive to improving the efficiency of the ring opening / prepolymerization reaction and reducing the reaction time under high temperature and high pressure.

[0011] Preferably, the high temperature resistant nylon obtained in step (3) is PA5T. PA5T is a bio-based high temperature resistant nylon, and side reactions are very likely to occur during the polymerization process, because pentamethylenediamine cyclizes at high temperature (>250°C) to form piperidine, and then piperidine and terephthalic acid condense to form terephthalic acid dipiperidine, which is further oxidized to form a new carbonyl structure - terephthalic acid di(2-carbonyl substituted piperidine) on the α-methylene next to the amino group. The presence of this α-ketoamide group causes the product to turn yellow. As the residence time of the polymerization reaction at high temperature increases, more terephthalic acid di(2-carbonyl substituted piperidine) is generated, and the color of PA5T will gradually darken. In addition, the molar ratio of dibasic acid to diamine monomer is unbalanced, and the condensation of piperidine with active oligomers leads to the inactivation of the polyamide growth chain, which makes it difficult to increase the molecular weight of the polymer. Moreover, since pentamethylenediamine 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 path, and the pyrolysis products also contain piperidine and piperidine derivatives, which affect the color quality of the product. The reaction temperature of the entire polymerization (including prepolymerization and polycondensation) pipeline of the present invention is relatively close and is lower than 250°C, which can avoid the occurrence of side reactions of pentamethylenediamine in the production process and obtain PA5T with good performance.

[0012] Preferably, the mixing condition in step (1) is stirring at 50-70° C. for 1-3 h.

[0013] Preferably, the conditions for the salt formation reaction in step (1) are 120-160° C. and 0.5-1.5 MPa for 1-2 hours. The salt formation of the present invention adopts high temperature and high pressure to improve the reaction efficiency, omit the concentration process, and reduce energy consumption.

[0014] Preferably, the temperature of the prepolymerization reaction in step (2) is 220-250°C, the pressure is 1.5-2.5 MPa, 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 less residue.

[0015] Preferably, the product of the prepolymerization reaction in step (2) is sprayed into a drying tower at a pressure of 1.0-2.0 MPa, and then separated by a cyclone separator to obtain a powdered prepolymer.

[0016] Preferably, the reaction pressure of the primary polycondensation in step (3) is 1000-500 mbar absolute pressure, and the reaction time is 1-6 hours. The primary polycondensation stage of the present invention is carried out under solid material to reduce adhesion residue, reduce oxidation, and improve product quality.

[0017] Preferably, the reaction pressure of the secondary polycondensation in step (3) is an absolute pressure ≤ 1 mbar, and the reaction time is 2-6 h.

[0018] As a preferred method, the entire production process is run under the protection of nitrogen or inert gas, and the materials are also transported by nitrogen or inert gas, so as to ensure that the materials are not easily oxidized at high temperatures and ensure product quality.

[0019] The present invention also provides a high-temperature resistant nylon continuous production device, which is a supporting device for the above-mentioned production method, comprising a mixing tank, a salt-forming kettle, a storage tank, an open-loop prepolymerization kettle, a drying tower, a cyclone separator and a condensation system connected in sequence, wherein the open-loop prepolymerization kettle is a tubular polymerization reactor.

[0020] Preferably, the polycondensation system comprises a storage tank, a primary polycondensation vessel, a buffer tank, a secondary polycondensation vessel and a finished product tank which are connected in sequence, and the cyclone separator is connected to the storage tank.

[0021] Therefore, the beneficial effects of the present invention are as follows: (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 pentamethylenediamine; (2) the salt formation adopts high temperature and high pressure salt formation, which improves the reaction efficiency, eliminates the concentration process, and reduces energy consumption; (3) the prepolymerization stage is carried out in a tubular polymerization reactor, which can greatly improve the uniformity of the copolymer components, ensure the uniformity and stability of the product quality, and is conducive to improving the efficiency of the ring-opening / prepolymerization reaction and reducing the reaction time under high temperature and high pressure; (4) the salt formation / prepolymerization stage are both solution systems with low viscosity and less residue; (5) the primary polycondensation stage is carried out under solid material to reduce adhesion residues. Retention, reducing oxidation and improving product quality; (6) The polycondensation stage is carried out below the melting point of the material, and the material is not easy to stick together, which solves the problem of the influence of long-term high-temperature oxidation of residual materials on the product color and the problem of excessive transition materials between different batches. It is convenient to adjust the formula and change the variety in real time online, reduce the generation of transition materials, and reduce the start-up cost; (7) The reaction temperature of the entire polymerization pipeline is relatively close, and no high heat medium system is required, which can greatly reduce energy consumption and reduce the requirements for equipment; (8) The entire polymerization pipeline and container are operated under the protection of inert gas, and the material is also transported by inert gas to ensure that the material is not easy to oxidize at high temperature and ensure product quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 Schematic diagram of the device of the present invention.

[0023] In the figure, 1. mixing tank, 2. salt forming kettle, 3. storage tank, 4. tubular polymerization reactor, 5. drying tower, 6. cyclone separator, 7. storage tank, 8. primary polycondenser, 9. buffer tank, 10. secondary polycondenser, 11. finished product tank. DETAILED DESCRIPTION

[0024] The technical solution of the present invention is further described below through specific embodiments.

[0025] 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 embodiments, unless otherwise specified, are all conventional methods in the art.

[0026] Overall embodiment

[0027] A continuous production method for high temperature resistant nylon comprises the following steps:

[0028] (1) Salt formation: Add dibasic acid, diamine, lactam, reaction aid and deionized water into a mixing tank, mix and transfer to a salt forming kettle to react to obtain a nylon salt solution. The reaction conditions are 120-160°C and 0.5-1.5 MPa for 1-2 hours.

[0029] (2) Ring-opening prepolymerization: The nylon salt solution is subjected to a prepolymerization reaction in a ring-opening prepolymerization reactor to cause the lactam to open its ring and the nylon salt to prepolymerize. The reaction conditions are 210-250°C and 1.5-2.5 MPa for 3-8 hours. After the reaction, the solution is sprayed into a drying tower at a pressure of 1.0-2.0 MPa and separated by a cyclone separator to obtain a powdered prepolymer.

[0030] (3) Solid-phase polycondensation: The powder prepolymer is first transported to a primary polycondensation vessel by nitrogen or inert gas for preliminary viscosity increase, with the absolute pressure controlled at 900-500 mbar, the reaction temperature at 200-230°C, and the residence time at 1-6 h; then it passes through a buffer tank into a secondary polycondensation vessel to obtain powdered high-temperature resistant nylon, with the absolute pressure controlled within 1 mbar, the reaction temperature at 230-250°C, and the residence time at 2-6 h.

[0031] As a preferred embodiment, the present invention also provides the above-mentioned high temperature resistant nylon continuous production device, such as Figure 1 As shown, it includes a mixing tank, a salt forming kettle, a storage tank, an open-loop prepolymerization kettle, a drying tower, a cyclone separator and a polycondensation system connected in sequence, wherein the polycondensation system includes a storage tank, a primary polycondensation vessel, a buffer tank, a secondary polycondensation vessel and a finished product tank connected in sequence, and the cyclone separator is connected to the storage tank. The open-loop prepolymerization kettle is a tubular polymerization reactor.

[0032] Example 1

[0033] A high temperature resistant nylon continuous production device Figure 1 As shown, 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, a storage tank 7, a primary polycondenser 8, a buffer tank 9, a secondary polycondenser 10 and a finished product tank 11 are connected in sequence.

[0034] A continuous production method of high temperature resistant nylon PA6T / 6, comprising the following steps:

[0035] (1) Salt formation: 249.20 kg of terephthalic acid, 174.30 kg of hexamethylenediamine, 113.16 kg of caprolactam, 1.2 kg of phosphoric acid catalyst and 200 kg of deionized water were added to mixing tank 1, heated to 60°C, stirred for 1 hour, transferred to salt-forming kettle 2, heated to 150°C, controlled the pressure to 0.5 MPa, reacted for 1 hour, and obtained PA6T / 6 salt solution, which was transferred to storage tank 3 for storage.

[0036] (2) Ring-opening prepolymerization: The nylon salt solution is subjected to a prepolymerization reaction in a ring-opening prepolymerization kettle, i.e., a tubular polymerization reactor 4, to cause the lactam to open its ring and the nylon salt to prepolymerize. The reaction conditions are 220° C. (upper end temperature) and 1.5 MPa for 5 hours. After the reaction, the solution is sprayed into a drying tower 5 at a pressure of 1.0 MPa, separated by a cyclone separator 6 to obtain a dry powdered prepolymer, which is then transferred to a storage tank 7 for storage.

[0037] (3) Solid-phase polycondensation: The powder prepolymer is first transported to the primary polycondensation vessel 8 by nitrogen for preliminary viscosity increase, and the pressure is controlled to be slightly negative, with an absolute pressure of 800 mbar, a reaction temperature of 230°C, and a residence time of 2 h; then it enters the secondary polycondensation vessel 10 through the buffer tank 9, with an absolute pressure of 0.5 mbar, a reaction temperature of 250°C, and a residence time of 3 h, to obtain powdered high-temperature resistant nylon PA6T / 6, which is then transferred to the finished product tank 11 for storage.

[0038] Example 2

[0039] The difference from Example 1 is that the residence time in the secondary polycondenser in step (3) is 6 hours.

[0040] Example 3

[0041] A continuous production method for high temperature resistant nylon PA5T / 6, comprising the following steps:

[0042] (1) Salt formation: 249.20 kg of terephthalic acid, 153.27 kg of pentamethylenediamine, 113.16 kg of caprolactam, 1.15 kg of phosphoric acid catalyst and 200 kg of deionized water were added to mixing tank 1, heated to 60° C., stirred for 1 h, transferred to salt-forming kettle 2, heated to 150° C., controlled the pressure to 0.5 MPa, reacted for 1 h, and obtained PA5T / 6 salt solution, which was transferred to storage tank 3 for storage.

[0043] (2) Ring-opening prepolymerization: The nylon salt solution is subjected to a prepolymerization reaction in a ring-opening prepolymerization kettle, i.e., a tubular polymerization reactor 4, to cause the lactam to open its ring and the nylon salt to prepolymerize. The reaction conditions are 220° C. (upper end temperature) and 1.5 MPa for 5 hours. After the reaction, the solution is sprayed into a drying tower 5 at a pressure of 1.0 MPa, separated by a cyclone separator 6 to obtain a dry powdered prepolymer, which is then transferred to a storage tank 7 for storage.

[0044] (3) Solid-phase polycondensation: The powder prepolymer is first transported to the primary polycondensation vessel 8 by nitrogen for preliminary viscosity increase, and the pressure is controlled to be slightly negative, with an absolute pressure of 800 mbar, a reaction temperature of 220°C, and a residence time of 2 h; then it enters the secondary polycondensation vessel 10 through the buffer tank 9, with an absolute pressure of 0.5 mbar, a reaction temperature of 250°C, and a residence time of 3 h, to obtain powdered high-temperature resistant nylon PA5T / 6, which is then transferred to the finished product tank 11 for storage.

[0045] Example 4

[0046] The difference from Example 3 is that the residence time in the secondary polycondenser in step (3) is 6 hours.

[0047] Example 5

[0048] A continuous production method of high temperature resistant nylon PA6T / 66, comprising the following steps:

[0049] (1) Salt formation: 249.20 kg of terephthalic acid, 146.10 kg of adipic acid, 290.50 kg of hexamethylenediamine, 1.5 kg of phosphoric acid catalyst and 270 kg of deionized water were added to mixing tank 1, heated to 60° C., stirred for 1 h, transferred to salting kettle 2, heated to 150° C., controlled pressure at 0.5 MPa, reacted for 1 h, and PA6T / 66 salt solution was obtained, which was transferred to storage tank 3 for storage.

[0050] (2) Ring-opening prepolymerization: The nylon salt solution is subjected to a prepolymerization reaction in a ring-opening prepolymerization kettle, i.e., a tubular polymerization reactor 4, to cause the lactam to open its ring and the nylon salt to prepolymerize. The reaction conditions are 220° C. (upper end temperature) and 1.5 MPa for 5 hours. After the reaction, the solution is sprayed into a drying tower 5 at a pressure of 1.0 MPa, separated by a cyclone separator 6 to obtain a dry powdered prepolymer, which is then transferred to a storage tank 7 for storage.

[0051] (3) Solid-phase polycondensation: The powder prepolymer is first transported to the primary polycondensation vessel 8 by nitrogen for preliminary viscosity increase, and the pressure is controlled to be slightly negative, with an absolute pressure of 800 mbar, a reaction temperature of 230°C, and a residence time of 2 h; then it enters the secondary polycondensation vessel 10 through the buffer tank 9, with an absolute pressure of 0.5 mbar, a reaction temperature of 250°C, and a residence time of 3 h, to obtain powdered high-temperature resistant nylon PA6T / 66, which is then transferred to the finished product tank 11 for storage.

[0052] Example 6

[0053] The difference from Example 5 is that the residence time in the secondary polycondensation vessel in step (3) is 6 hours.

[0054] Example 7

[0055] A continuous production method of high temperature resistant nylon PA10T, comprising the following steps:

[0056] (1) Salt formation: 249.20 kg of terephthalic acid, 258.46 kg of decanediamine, 1.2 kg of phosphoric acid catalyst and 300 kg of deionized water were added to mixing tank 1, heated to 60° C., stirred continuously for 1 hour, transferred to salt-forming kettle 2, heated to 150° C., controlled pressure at 0.5 MPa, reacted for 1 hour to obtain PA10T salt solution, which was transferred to storage tank 3 for storage.

[0057] (2) Ring-opening prepolymerization: The nylon salt solution is subjected to a prepolymerization reaction in a ring-opening prepolymerization kettle, i.e., a tubular polymerization reactor 4, to cause the lactam to open its ring and the nylon salt to prepolymerize. The reaction conditions are 220° C. (upper end temperature) and 1.5 MPa for 5 hours. After the reaction, the solution is sprayed into a drying tower 5 at a pressure of 1.0 MPa, separated by a cyclone separator 6 to obtain a dry powdered prepolymer, which is then transferred to a storage tank 7 for storage.

[0058] (3) Solid-phase polycondensation: The powder prepolymer is first transported to the primary polycondensation vessel 8 by nitrogen for preliminary viscosity increase, and the pressure is controlled to be slightly negative, with an absolute pressure of 800 mbar, a reaction temperature of 220°C, and a residence time of 3 h; then it enters the secondary polycondensation vessel 10 through the buffer tank 9, with an absolute pressure of 0.5 mbar, a reaction temperature of 250°C, and a residence time of 4 h, to obtain a powdered high-temperature resistant nylon PA10T, which is then transferred to the finished product tank 11 for storage.

[0059] Example 8

[0060] The difference from Example 7 is that the residence time in the secondary polycondenser in step (3) is 7 hours.

[0061] Comparative Example 1

[0062] A continuous production method for high temperature resistant nylon PA6T / 6, which differs from Example 1 in that the method described in patent CN112979941A is adopted.

[0063] Comparative Example 2

[0064] A continuous production method for high temperature resistant nylon PA5T / 6, which differs from Example 3 in that the method described in patent CN112979941A is adopted.

[0065] Comparative Example 3

[0066] A continuous production method for high temperature resistant nylon PA6T / 66, which is different from Example 5 in that PA6T / 66 is prepared by the method described in patent CN112979941A. The types and amounts of raw materials are the same as those in Example 5.

[0067] Comparative Example 4

[0068] A continuous production method for high temperature resistant nylon PA10T, which differs from Example 7 in that the method described in patent CN112979941A is adopted.

[0069] Comparative Example 5

[0070] A continuous production method for high temperature resistant nylon PA5T / 6, which differs from Example 3 in that the method described in patent CN105330846A is adopted.

[0071] Performance Testing

[0072] The performance tests were carried out on the products of the above embodiments and comparative examples, and the test equipment and test standards used were as follows:

[0073]

[0074] The characterization results are shown in the following table.

[0075]

[0076] As can be seen from the above table, the present invention is applicable to the production of various types of high temperature resistant nylons, especially bio-based high temperature resistant nylon PA5T, and the product has excellent thermal and mechanical properties, and its relative viscosity can be regulated by the reaction time. Comparative Examples 1, 2, and 3 use PA6T / 6, PA5T / 6, and PA6T / 66 prepared by caprolactam copolymerization using patent CN112979941A to produce high temperature resistant nylons that have multiple melting peaks, and their mechanical strength is significantly lower than that of Examples 1, 3, and 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 nylons prepared by the method described in the present invention all have a single melting point, good uniformity, and more excellent performance. The performance of Comparative Example 4 and Example 7 is basically the same, indicating that both inventive methods are applicable to the production of single-component high temperature resistant nylons. The bio-based high temperature resistant nylon PA5T prepared by the present method in Examples 3 and 4 has good hue and high relative viscosity, and can meet the subsequent use requirements. This is because the present invention controls the entire reaction process and can produce PA5T under the condition that the reaction temperature of the polymerization pipeline is not higher than 250°C, which effectively avoids the side reaction of the bio-based monomer pentamethylenediamine. The PA5T prepared by the prior art in Comparative Example 5 has poor hue and low relative viscosity, and its performance is far inferior to that of the present invention.

[0077] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technician familiar with this profession can make some changes or modifications to equivalent embodiments of equivalent changes using the technical contents disclosed above without departing from the scope of the technical solution of the present invention. However, any simple modification, equivalent change and modification made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. A continuous production method for high temperature resistant nylon, characterized in that: Included steps (1) Mix the dibasic acid, diamine, lactam, reaction aid and water, and perform salt formation reaction at 120-160°C and 0.5-1.5 MPa for 1-2 hours to obtain a nylon salt solution; (2) Prepolymerizing the nylon salt solution in a tubular polymerization reactor at 220-250°C and 1.5-2.5 MPa for 3-8 hours, and drying to obtain a powdered prepolymer; (3) Solid phase polycondensation: The powder prepolymer is firstly polycondensed in a primary polycondensation vessel at an absolute pressure of 1000-500 mbar for 1-6 hours, and then polycondensed in a secondary polycondensation vessel at an absolute pressure of ≤1 mbar for 2-6 hours to obtain powdered high temperature resistant nylon; The reaction temperatures of the prepolymerization, primary polycondensation and secondary polycondensation are 200-250°C, and the polycondensation stages are all carried out below the melting point of the materials. The secondary polycondensation temperature is higher than the primary polycondensation temperature.

2. A method for continuous production of high temperature resistant nylon according to claim 1, characterized in that: The mixing condition in step (1) is stirring at 50-70°C for 1-3 h.

3. The method for continuous production of high temperature resistant nylon according to claim 1, characterized in that: The temperature of the prepolymerization reaction in step (2) is 210-250°C.

4. The method for continuous production of high temperature resistant nylon according to claim 1, characterized in that: The reaction temperature of the primary polycondensation in step (3) is 200-230°C.

5. The method for continuous production of high temperature resistant nylon according to claim 1, characterized in that: The reaction temperature of the secondary polycondensation in step (3) is 230-250°C.

6. A method for continuous production of high temperature resistant nylon according to claim 1 or 3 or 4 or 5, characterized in that: The high temperature resistant nylon obtained in step (3) is PA6T / 6, PA5T / 6, and PA6T / 66.

7. A method for continuous production of high temperature resistant nylon according to claim 1 or 3 or 4 or 5, characterized in that: The high temperature resistant nylon obtained in step (3) is PA5T.

8. The method for continuous production of high temperature resistant nylon according to claim 1, characterized in that: The product of the prepolymerization reaction in step (2) is sprayed into a drying tower at a pressure of 1.0-2.0 MPa, and then separated by a cyclone separator to obtain a powdered prepolymer.

9. The device used in the production method according to any one of claims 1 to 8, characterized in that: The invention comprises a mixing tank, a salt forming kettle, a storage tank, a ring-opening prepolymerization kettle, a drying tower, a cyclone separator and a polycondensation system which are connected in sequence, wherein the ring-opening prepolymerization kettle is a tubular polymerization reactor.

10. The device according to claim 9, characterized in that The polycondensation system comprises a storage tank, a primary polycondensation device, a buffer tank, a secondary polycondensation device and a finished product tank which are connected in sequence, and the cyclone separator is connected to the storage tank.

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