Super weather-resistant nylon 6 resin as well as preparation method and application thereof

Abstract

The invention discloses super-weather-resistant nylon 6 resin as well as a preparation method and application thereof, and the super-weather-resistant nylon 6 resin is prepared by the following steps: carrying out salt forming reaction on aromatic dibasic acid containing hindered amine functional groups and aliphatic diamine to obtain nylon salt, compounding hindered phenol and phosphite antioxidants, and then copolymerizing with caprolactam to obtain the super-weather-resistant nylon 6 resin. The super-weather-resistant nylon 6 resin with ultraviolet resistance and thermo-oxidative aging resistance is obtained. The super-weather-resistant nylon 6 resin is excellent in product diversity, weather resistance, heat resistance and the like, the related preparation method has the advantages of being simple in technological process, capable of achieving industrial continuous production and the like, and the related product is widely applied to the fields of new energy automobiles, rail transit, electronics and electricity, film packaging and the like and especially suitable for outdoor places.

Description

Technical Field

[0001] The present invention relates to the technical field of nylon, and in particular to a super-weather-resistant nylon 6 resin and a preparation method and application thereof. Background Art

[0002] Nylon, scientifically known as polyamide, is a type of polymer containing amide bonds in its molecular chain. Initially used in fibers, nylon was introduced in 1952 by DuPont to replace traditional metal materials with nylon 66 in engineering plastics to meet the low-cost requirements of downstream industrial enterprises. Today, nylon holds a significant position in the engineering plastics sector, widely used in the manufacture of mechanical parts, automotive accessories, and electrical housings. However, due to the presence of amide bonds, nylon is susceptible to environmental influences such as light or heat and oxygen during use, resulting in reduced weather resistance and a significantly shortened product lifespan.

[0003] Chinese patent CN 112500700A relates to a blow-moldable weather-resistant nylon composition and its preparation method, comprising nylon resin, a tackifier, Surlyn resin, titanium dioxide, and other additives. By introducing a compound system of Surlyn resin and titanium dioxide, the weather resistance of the nylon material is significantly improved. The introduction of the tackifier further increases the resin melt viscosity, making the nylon material more conducive to blow molding and applicable to working conditions requiring long-term light exposure. However, the large proportion of Surlyn resin and the poor dispersion uniformity of the filler affect the mechanical strength of the weather-resistant nylon composition. Chinese patent CN 116478535A discloses a wear-resistant and weather-resistant nylon composite material, which is prepared from the following raw materials in parts by weight: 100-140 parts of nylon resin, 10-15 parts of functional material, 15-25 parts of filler, and 2-10 parts of auxiliary agent; the functional material is a mixture of 1 part of polysiloxane, 10 parts of thermoplastic elastomer TPAE and 1-2 parts of MoS2. The present invention forms the functional material by blending nylon resin, polysiloxane, thermoplastic elastomer TPAE and MoS2, and improves the wear resistance of the product by adding fillers. The heat resistance and aging resistance are improved by compounding stabilizers and fillers. Under the action of the auxiliary agent, the various components work synergistically to obtain a highly wear-resistant and weather-resistant nylon composite material. The wear resistance and weather resistance can be slightly improved by blending, but it is difficult to achieve an exponential improvement.

[0004] In summary, the currently reported methods for obtaining weather-resistant nylon resins are basically based on blending modification, but there are no reports in the prior art on obtaining super-weather-resistant nylon 6 resins with both weather resistance and heat resistance through copolymerization or in-situ polymerization, as well as their preparation methods and applications. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to overcome the above-mentioned defects of the prior art and provide a super-weather-resistant nylon 6 resin with a simple process flow and industrialized continuous production, as well as its preparation method and application. The specific technical solution is as follows: The inventive concept of the super-weather-resistant nylon 6 resin of the present invention is: an aromatic dibasic acid containing a hindered amine functional group and an aliphatic diamine are reacted to form a nylon salt, and a hindered phenol and a phosphite antioxidant are compounded, and then copolymerized with caprolactam to obtain a super-weather-resistant nylon 6 resin that is resistant to ultraviolet light, thermal oxidative aging and high heat.

[0006] A super weather-resistant nylon 6 resin, wherein the molecular side chain of the super weather-resistant nylon 6 resin has a hindered amine functional group; the molecular structure of the super weather-resistant nylon 6 resin is: Among them, a=1, 2, 5, 6, 8, 10, n=3~20, m=190~205.

[0007] A method for preparing super weather-resistant nylon 6 resin comprises the following steps: Step 1: An aromatic dibasic acid containing a hindered amine functional group and an aliphatic diamine are salted in pure water to obtain a nylon salt solution S1; Step 2: Add a certain ratio of nylon salt solution S1, caprolactam, compound hindered phenol antioxidant, phosphite antioxidant and catalyst into the reactor. After adding the materials, replace the air in the reactor with inert gas 3 to 4 times, carry out melt polycondensation, then fill in inert gas, discharge the materials, and obtain super weather resistant nylon 6 resin.

[0008] The aliphatic diamine includes one or more of pentamethylenediamine, hexamethylenediamine, nonamethylenediamine, decamethylenediamine, 1,12-diaminododecane or 1,14-diaminotetradecane.

[0009] The molar ratio of the aromatic dibasic acid containing hindered amine functional groups to the aliphatic diamine is 0.96-1.00:1.00, and the amount of water used is 40-50% of the total mass of the dibasic acid and the diamine.

[0010] The amount of nylon salt solution S1 used is 2.0-20.0% of the mass of caprolactam, more preferably 5.0-15.0%.

[0011] The amount of the hindered phenol antioxidant is 0.1 to 0.3% of the mass of caprolactam, and the hindered phenol antioxidant includes one or more of Irganox 245, Irganox 1010, Irganox 1035, Irganox 1076, Irganox 1098, Irganox 1330, Irganox 3114 or Irganox GX MD 1024.

[0012] The amount of the phosphite antioxidant is 0.1 to 0.3% of the mass of the caprolactam, and the phosphite antioxidant includes one or more of lrgafos 168, SARAFOS 2626, SARAFOS 2627, SARAFOS 2628 or SARAFOS 2628P5.

[0013] The amount of the catalyst used is 0.2-0.5% of the mass of caprolactam, and the catalyst includes one or more of sodium hypophosphite, potassium hypophosphite or magnesium hypophosphite.

[0014] Among them, the specific process of melt polycondensation is: first carry out a temperature-raising and pressure-maintaining reaction, slowly release the gas and carry out a second temperature-raising and pressure-maintaining reaction, release the gas to normal pressure, discharge the water in the system, and then gradually vacuumize and carry out a pressure reduction reaction; the first temperature-raising and pressure-maintaining reaction refers to: heating to 200-210 ° C, and maintaining the pressure in the kettle at 2.0-2.3 MPa, and reacting for 1.5-2.0 hours; the slow release and second temperature-raising and pressure-maintaining reaction refers to: continuing to heat to 240-255 ° C, slowly releasing the gas during the heating process to maintain the pressure in the kettle at 0.9-1.2 MPa, and reacting for 1.5-2.0 hours; the gradual vacuuming and pressure reduction The reaction refers to: first evacuating to -0.01 to -0.03 MPa, maintaining the pressure for 20 to 30 minutes, then evacuating to -0.03 to -0.05 MPa, maintaining the pressure for 20 to 30 minutes, and finally evacuating to -0.05 to -0.07 MPa, maintaining the pressure for 30 to 40 minutes; before the melt polycondensation, the air in the reactor is replaced with an inert gas 3 to 4 times and the inert gas is filled to 0.1 to 0.2 MPa; after the melt polycondensation, the inert gas is filled to 0.2 to 0.3 MPa; the inert gas includes one or more of carbon dioxide, nitrogen, argon or helium.

[0015] The above-mentioned super weather-resistant nylon 6 nylon resin is used in new energy vehicles, rail transportation, electronics and electrical, film packaging and other fields, especially suitable for outdoor places.

[0016] Compared with the closest existing technology, the technical solution provided by the present invention has the following beneficial effects: (1) The relative viscosity of the super weather-resistant nylon 6 resin of the present invention is as high as 2.5, the tensile strength is as high as 74.7 MPa, the flexural strength is as high as 94.6 MPa, and the impact strength is as high as 7.0 kJ / m 2 The initial decomposition temperature is as high as 390.5℃. After exposure to a xenon arc lamp aging test chamber for 1000h, its color change value (ΔE) is ≤5.8. After aging treatment at 150℃ for 1000h, its yellowing index (YI) is ≤5.5. There is almost no precipitation of antioxidants, and the service life of the product is significantly extended.

[0017] (2) The super weather-resistant nylon 6 resin of the present invention has diversified products. The copolymerization ratio of caprolactam and copolymer component S1 can be flexibly adjusted, and hindered phenols and phosphite antioxidants can be compounded to customize the production of nylon 6 resins with different heat resistance and weather resistance grades, so as to be suitable for special places with strict requirements on weather resistance and heat resistance.

[0018] (3) The production process involved in the method of the present invention is simple and can realize industrial continuous production. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a molecular structural diagram of the super weather-resistant nylon 6 resin of the present invention. DETAILED DESCRIPTION

[0020] The present invention is further described below with reference to the following examples. The inert gas used in the examples and comparative examples of the present invention is a high-purity gas with a purity of ≥99.999%. The raw materials or chemical reagents used in the examples and comparative examples of the present invention, unless otherwise specified, can be obtained through conventional commercial channels.

[0021] Example 1 (1) Weigh 348.2 g (1.0 mol) of an aromatic dibasic acid containing a hindered amine functional group and 116.2 g (1.0 mol) of hexamethylenediamine in 185.8 g (40%) of pure water to form a salt to obtain nylon salt solution S1; (2) 13004.0g caprolactam, 650.2g nylon salt solution S1, 14.0g hindered phenol antioxidant Irganox1010, 14.0g phosphite antioxidant SARAFOS 2626 and 28.0g of catalyst sodium hypophosphite were put into the reactor. After the feeding, the air in the reactor was replaced with nitrogen 3 to 4 times, and high-purity nitrogen was filled to 0.15MPa, and then melt polycondensation was carried out: first, the temperature was raised to 209°C, and the pressure in the reactor was maintained at 2.1MPa. A temperature-raising and pressure-maintaining reaction was carried out for 2.0h, and the temperature was continued to be raised to 248°C. During the heating process, the gas was slowly released to maintain the pressure in the reactor at 1.0MPa, and a second temperature-raising and pressure-maintaining reaction was carried out for 1.5h. The pressure in the reactor was released to normal pressure, and the water in the system was discharged. The vacuum pump was used to gradually evacuate the reactor for a reduced pressure reaction: first, the vacuum was evacuated to -0.02MPa, the pressure was maintained for 25min, then the vacuum was evacuated to -0.04MPa, the pressure was maintained for 25min, and finally the vacuum was evacuated to -0.06MPa, the pressure was maintained for 30min, and high-purity nitrogen was filled to 0.3MPa, and the material was discharged to obtain super weather-resistant nylon 6 resin.

[0022] Example 2 (1) Weigh 348.2 g (1.0 mol) of an aromatic dibasic acid containing a hindered amine functional group and 116.2 g (1.0 mol) of hexamethylenediamine in 185.8 g (40%) of pure water to form a salt to obtain nylon salt solution S1; (2) 8127.5g caprolactam, 650.2g nylon salt solution S1, 9.0g hindered phenol antioxidant Irganox 1076, 9.0g phosphite antioxidant SARAFOS 2628g and 18.0g catalyst sodium hypophosphite were put into the reactor. After the feeding, the air in the reactor was replaced with nitrogen 3 to 4 times, and high-purity nitrogen was filled to 0.15MPa, and then melt polycondensation was carried out: first, the temperature was raised to 208°C, and the pressure in the reactor was maintained at 2.0MPa. A temperature-raising and pressure-maintaining reaction was carried out for 2.0h, and the temperature was continued to be raised to 245°C. During the heating process, the gas was slowly released to maintain the pressure in the reactor at 1.0MPa, and a second temperature-raising and pressure-maintaining reaction was carried out for 1.5h. The pressure in the reactor was released to normal pressure, and the water in the system was discharged. The vacuum pump was gradually used to evacuate the reactor for a reduced pressure reaction: first, the vacuum was evacuated to -0.02MPa, the pressure was maintained for 25min, then the vacuum was evacuated to -0.04MPa, the pressure was maintained for 25min, and finally the vacuum was evacuated to -0.06MPa, the pressure was maintained for 30min, and high-purity nitrogen was filled to 0.3MPa, and the material was discharged to obtain super weather-resistant nylon 6 resin.

[0023] Example 3 (1) Weigh 348.2 g (1.0 mol) of an aromatic dibasic acid containing a hindered amine functional group and 116.2 g (1.0 mol) of hexamethylenediamine in 185.8 g (40%) of pure water to form a salt to obtain nylon salt solution S1; (2) 6502.0g caprolactam, 650.2g nylon salt solution S1, 7.0g hindered phenol antioxidant Irganox 245, 7.0g phosphite antioxidant lrgafos 168g and 14.0g of catalyst sodium hypophosphite were put into the reactor. After the feeding, the air in the reactor was replaced with nitrogen 3 to 4 times, and high-purity nitrogen was filled to 0.15MPa, and then melt polycondensation was carried out: first, the temperature was raised to 208°C, and the pressure in the reactor was maintained at 2.0MPa. A temperature-raising and pressure-maintaining reaction was carried out for 2.0h, and the temperature was continued to be raised to 245°C. During the heating process, the gas was slowly released to maintain the pressure in the reactor at 1.0MPa, and a second temperature-raising and pressure-maintaining reaction was carried out for 1.5h. The pressure in the reactor was released to normal pressure, and the water in the system was discharged. The vacuum pump was gradually used to evacuate the reactor for a reduced pressure reaction: first, the vacuum was evacuated to -0.02MPa, the pressure was maintained for 25min, then the vacuum was evacuated to -0.04MPa, the pressure was maintained for 25min, and finally the vacuum was evacuated to -0.06MPa, the pressure was maintained for 30min, and high-purity nitrogen was filled to 0.3MPa, and the material was discharged to obtain super weather-resistant nylon 6 resin.

[0024] Example 4 (1) Weigh 348.2 g (1.0 mol) of an aromatic dibasic acid containing a hindered amine functional group and 116.2 g (1.0 mol) of hexamethylenediamine in 185.8 g (40%) of pure water to form a salt to obtain nylon salt solution S1; (2) 4334.7g caprolactam, 650.2g nylon salt solution S1, 5.0g hindered phenol antioxidant Irganox 245, 5.0g phosphite antioxidant lrgafos 168g and 10.0g of catalyst sodium hypophosphite are put into the reactor. After the feeding, the air in the reactor is replaced with nitrogen 3 to 4 times, and high-purity nitrogen is filled to 0.15MPa, and then melt polycondensation is carried out: first, the temperature is raised to 208°C, and the pressure in the reactor is maintained at 2.0MPa. A temperature increase and pressure holding reaction is carried out for 2.0h, and the temperature is continued to be raised to 245°C. During the temperature increase process, the gas is slowly released to maintain the pressure in the reactor at 1.0MPa, and a second temperature increase and pressure holding reaction is carried out for 1.5h. The pressure in the reactor is released to normal pressure, and after discharging the water in the system, a vacuum pump is used to gradually evacuate the reactor for a reduced pressure reaction: first, evacuate to -0.02MPa, maintain the pressure for 25min, then evacuate to -0.04MPa, maintain the pressure for 25min, and finally evacuate to -0.06MPa, maintain the pressure for 30min, then fill with high-purity nitrogen to 0.3MPa, discharge the material, and obtain super weather resistant nylon 6 resin.

[0025] Comparative Example 1 6502.0g of caprolactam, 185.8g of pure water, 7.0g of hindered phenol antioxidant Irganox 245, 7.0g of phosphite antioxidant lrgafos 168 and 14.0g of catalyst sodium hypophosphite were added to a reactor. After the addition of the materials, the air in the reactor was replaced with nitrogen 3-4 times and filled with high-purity nitrogen to 0.15MPa. Melt polycondensation was carried out: first, the temperature was raised to 208℃ and the pressure in the reactor was maintained at 2.0MPa. A temperature-raising and pressure-holding reaction was carried out for 2.0h. The temperature was then raised to 245℃. During the temperature-raising process, the gas was slowly released to maintain the pressure in the reactor at 1.0MPa. A second temperature-raising and pressure-holding reaction was carried out for 1. After 5 hours, the pressure in the reactor was released to normal pressure. After the water in the system was discharged, a vacuum pump was used to gradually evacuate the system for a reduced pressure reaction: first evacuate to -0.02 MPa, maintain the pressure for 25 minutes, then evacuate to -0.04 MPa, maintain the pressure for 25 minutes, and finally evacuate to -0.06 MPa, maintain the pressure for 30 minutes, and then fill with high-purity nitrogen to 0.3 MPa, discharge the material, and obtain the antioxidant in situ polymerization modified nylon 6 resin.

[0026] Comparative Example 2 6502.0g of caprolactam, 85.8g of pure water and 14.0g of sodium hypophosphite catalyst were added to the reactor. After the addition of the materials, the air in the reactor was replaced with nitrogen for 3 to 4 times, and high-purity nitrogen was filled to 0.15MPa, and then melt polycondensation was carried out: first, the temperature was raised to 208℃, and the pressure in the reactor was maintained at 2.0MPa. The temperature was raised and the pressure was maintained for 2.0h. The temperature was continued to be raised to 245℃. During the heating process, the gas was slowly released to maintain the pressure in the reactor at 1.0MPa, and the reaction was continued. After a secondary temperature-raising and pressure-maintaining reaction for 1.5 hours, the pressure in the reactor was released to normal pressure. After the water in the system was discharged, a vacuum pump was used to gradually evacuate the system for a reduced pressure reaction: first evacuate the system to -0.02 MPa, maintain the pressure for 25 minutes, then evacuate the system to -0.04 MPa, maintain the pressure for 25 minutes, and finally evacuate the system to -0.06 MPa, maintain the pressure for 30 minutes, and then fill in high-purity nitrogen to 0.3 MPa, discharge the material, and obtain ordinary nylon 6 resin.

[0027] In order to evaluate the relative viscosity, mechanical properties, heat resistance, and weather resistance of the super-weather-resistant nylon 6 resin Examples 1 to 4 and the nylon 6 resins of Comparative Examples 1 to 2 of the present invention, tests were conducted according to the following test conditions: Relative viscosity test conditions: The samples of the embodiment and comparative example were placed in a vacuum drying oven at 120°C for 4 hours, and then prepared into a concentrated sulfuric acid solution with a concentration of 0.010 g / mL. The test was performed using an automatic viscometer in accordance with the standard GB / T 38138-2019. Tensile strength test conditions: The tensile specimens were placed in a constant temperature and humidity chamber for 24 hours and tested using a testing machine in accordance with the standard GB / T 1040.2-2006; Bending strength test conditions: Place the bending specimen in a constant temperature and humidity chamber for 24 hours and use a testing machine to test according to standard GB / T 9341-2008; Impact strength test conditions: Place the impact specimen in a constant temperature and humidity chamber for 24 hours and use a testing machine to test according to standard GB / T 1043.1-2008; Melting point test conditions: Weigh 5-10 mg of the sample of the example or comparative example, heat the sample to 300°C and melt for 3 minutes under a high-purity nitrogen atmosphere, quench with liquid nitrogen, then heat the quenched sample to 300°C, cool to room temperature, and then heat it back to 300°C at a heating rate of 10°C / min, referring to standard GB / T 19466.3-2004; Decomposition onset temperature test conditions: Weigh 3-8 mg of the sample of the embodiment or comparative example and heat the sample to 700°C under a high-purity nitrogen atmosphere. The temperature corresponding to 5% weight loss is the decomposition onset temperature, according to the standard GB / T 33047.1-2016. UV aging test method: Use a xenon arc lamp aging test chamber with a total exposure time of 1000 hours and test its color change value (ΔE). The test standard is GB / T 16422.3-2014. Thermal oxidative aging test method: Place the nylon sample in a high-temperature oven and age it at 150°C for 1000 hours. Then test its yellowing index (YI). The test standard is GB / T 39822-2021.

[0028] The above test results are shown in Table 1.

[0029] Table 1 Relevant performance parameters of super weather-resistant nylon 6 resin Examples 1 to 4 and Comparative Examples 1 to 2 of the present invention As shown in Table 1, the relative viscosity of the super-weather nylon 6 resin embodiments 1 to 4 of the present invention is as high as 2.5, the tensile strength is as high as 74.7 MPa, the flexural strength is as high as 94.6 MPa, and the impact strength is as high as 7.0 kJ / m 2 The initial decomposition temperature is as high as 390.5°C, the color change value (ΔE) is ≤5.8 after exposure to a xenon arc lamp aging test chamber for 1000 hours, and the yellowing index (YI) is ≤5.5 after aging treatment at 150°C for 1000 hours, indicating that the super weather-resistant nylon 6 resin embodiments 1 to 4 of the present invention are suitable for special places with strict weather resistance and heat resistance. Compared with the antioxidant in-situ polymerization-modified nylon 6 resin obtained in comparative example 1 and the ordinary nylon 6 resin obtained in comparative example 2, the super weather-resistant nylon 6 resin of the present invention introduces a benzene ring structure and a hindered amine functional group as a side group into its molecular main chain by copolymerization, and is compounded with hindered phenols and phosphite antioxidants, thereby obtaining a super weather-resistant nylon 6 resin with both weather resistance and heat resistance, further broadening the application field of ordinary nylon 6 resin. The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the same. Although the present invention has been described in detail with reference to the above embodiments, a person skilled in the art may still modify or make equivalent substitutions to the specific implementations of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention are within the scope of protection of the claims of the present invention to be approved.

Claims

1. A super weather-resistant nylon 6 resin, characterized in that: The hindered amine functional group in the molecular side chain of super weather resistant nylon 6 resin; the molecular structure of super weather resistant nylon 6 resin is: ； Among them, a=1, 2, 5, 6, 8, 10, n=3~20, m=190~205.

2. The method for preparing super weather-resistant nylon 6 resin according to claim 1, characterized in that: The following steps are involved: Step 1: An aromatic dibasic acid containing a hindered amine functional group and an aliphatic diamine are salted in pure water to obtain a nylon salt solution S1; Step 2: Add a certain ratio of nylon salt solution S1, caprolactam, compound hindered phenol antioxidant, phosphite antioxidant and catalyst into the reactor. After adding the materials, replace the air in the reactor with inert gas 3 to 4 times, carry out melt polycondensation, then fill in inert gas, discharge the materials, and obtain super weather resistant nylon 6 resin.

3. The method for preparing super weather-resistant nylon 6 resin according to claim 2, characterized in that: In the step 1, the aliphatic diamine includes one or more of pentamethylenediamine, hexamethylenediamine, nonamethylenediamine, decamethylenediamine, 1,12-diaminododecane or 1,14-diaminotetradecane.

4. The method for preparing super weather-resistant nylon 6 resin according to claim 2, characterized in that: In step 1, the molar ratio of the aromatic dibasic acid containing hindered amine functional groups to the aliphatic diamine is 0.96-1.00:1.00, and the amount of water used is 40-50% of the total mass of the dibasic acid and the diamine.

5. The method for preparing super weather-resistant nylon 6 resin according to claim 2, characterized in that: In the step 2, the amount of the nylon salt solution S1 is 2.0 to 20.0% of the mass of the caprolactam.

6. The method for preparing super weather-resistant nylon 6 resin according to claim 2, characterized in that: In step 2, the amount of the hindered phenol antioxidant is 0.1-0.3% of the mass of caprolactam, and the hindered phenol antioxidant includes one or more of Irganox 245, Irganox 1010, Irganox 1035, Irganox 1076, Irganox 1098, Irganox 1330, Irganox 3114 or Irganox GX MD 1024.

7. The method for preparing super weather-resistant nylon 6 resin according to claim 2, characterized in that: In the step 2, the amount of the phosphite antioxidant is 0.1 to 0.3% of the mass of caprolactam, and the phosphite antioxidant includes one or more of lrgafos 168, SARAFOS 2626, SARAFOS 2627, SARAFOS 2628 or SARAFOS 2628P5.

8. The method for preparing super weather-resistant nylon 6 resin according to claim 2, characterized in that: In the step 2, the amount of the catalyst used is 0.2-0.5% of the mass of caprolactam, and the catalyst includes one or more of sodium hypophosphite, potassium hypophosphite or magnesium hypophosphite.

9. The method for preparing super weather-resistant nylon 6 resin according to claim 2, characterized in that: In the step 2, the specific process of the melt polycondensation is: first perform a temperature-raising and pressure-maintaining reaction, slowly release the gas and perform a second temperature-raising and pressure-maintaining reaction, release the gas to normal pressure, discharge the water in the system, and then gradually vacuumize and perform a pressure reduction reaction; the first temperature-raising and pressure-maintaining reaction refers to: heating to 200-210°C and maintaining the pressure in the kettle at 2.0-2.3MPa, and reacting for 1.5-2.0h; the slow release and second temperature-raising and pressure-maintaining reaction refers to: continuing to heat to 240-255°C, slowly releasing the gas during the heating process to maintain the pressure in the kettle at 0.9-1.2MPa, and reacting for 1.5-2.0h; the gradual vacuuming The reduced pressure reaction means: first evacuating to -0.01 to -0.03 MPa, maintaining the pressure for 20 to 30 minutes, then evacuating to -0.03 to -0.05 MPa, maintaining the pressure for 20 to 30 minutes, and finally evacuating to -0.05 to -0.07 MPa, maintaining the pressure for 30 to 40 minutes; before the melt polycondensation, replacing the air in the reactor with an inert gas 3 to 4 times and filling it with inert gas to 0.1 to 0.2 MPa; after the melt polycondensation, filling it with inert gas to 0.2 to 0.3 MPa; the inert gas includes one or more of carbon dioxide, nitrogen, argon or helium.

10. The use of the super weather-resistant nylon 6 resin according to claim 2, characterized in that: The super weather-resistant nylon 6 nylon resin described in claim 2 is applied to new energy vehicles, rail transportation, electronics and electrical equipment, film packaging and other fields as well as outdoor places.

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