High-heat-resistance nylon resin as well as preparation method and application thereof

Abstract

The invention relates to high-heat-resistance nylon resin and a preparation method and application thereof, and the high-heat-resistance nylon resin is mainly prepared from the following components: 2, 5-di (phenylamino)-1, 4-phthalic acid, linear or branched aliphatic diamine, a catalyst, an end-capping reagent and an anti-yellowing agent, and water is used as a reaction medium. The preparation method comprises the following steps: (1) stirring 2, 5-di (phenylamino)-1, 4-phthalic acid, linear or branched aliphatic diamine and water to form a salt; and (2) adding a catalyst, an end-capping reagent and an anti-yellowing agent, introducing inert gas, carrying out condensation polymerization reaction, introducing inert gas, and discharging to obtain the anti-yellowing polyurethane resin. The high-heat-resistance nylon resin is applied to the technical fields of surface mounting, electronic and electric appliances or automobile industry and the like. The high-heat-resistance nylon resin product is diversified, easy to process, high in mechanical strength, high in temperature resistance grade, low in water absorption and excellent in weather resistance. The product obtained by the method has few byproducts, and the process is simple and suitable for industrial continuous production.

Description

Technical Field

[0001] The invention relates to a nylon resin and a preparation method and application thereof, and in particular to a high-heat-resistant nylon resin and a preparation method and application thereof. Background Art

[0002] Polyamide (PA), commonly known as nylon, is obtained by polycondensation of dibasic acid and diamine or amino acid. It is a general term for resins containing repeated amide groups on the molecular chain. Nylon is the base resin with the largest output, the most varieties, the widest application and excellent comprehensive performance among the five general engineering plastics. The reason why nylon ranks first among the five major engineering plastics is mainly because it has many excellent properties and has outstanding advantages in mechanical properties, chemical properties, thermal properties, etc. After more than 70 years of development, the application of nylon has gradually expanded from spinning fibers to films, engineering plastics and other fields. With the rapid development of modern science and technology, the mechanical industry, automobile industry and electronic and electrical industry have higher requirements for the mechanical properties and heat resistance of nylon materials, especially the application demand in technical fields such as surface mounting, electronic appliances, and automobile industry is increasingly strong, which has promoted the rapid development of research and industrialization of high-temperature resistant nylon products.

[0003] The melting point of pure nylon 6T is higher than its decomposition temperature, and pure nylon 6T resin cannot be obtained by melt polymerization. A third monomer must be introduced to obtain copolymer modified nylon 6T resin with a melting point lower than the decomposition temperature by co-condensation. US5516882, US5981692 and US962628 disclose methods for synthesizing nylon 6T copolymers by high temperature melt polymerization at above 300°C using terephthalic acid, isophthalic acid, 1,6-hexanediamine, 1,6-hexanediamine and 2-methyl-1,5-pentanediamine as main raw materials; US6140459 discloses a method for synthesizing nylon 6T copolymers by melt polymerization using terephthalic acid, 1,6-hexanediamine and another aliphatic long chain dicarboxylic acid as raw materials. However, when melt polymerization is used to prepare semi-aromatic nylon, the temperature of the later polymerization reaction will exceed the melting point of the polymer, and the residence time at high temperature is too long, various side reactions and polymer degradation reactions are violent, which can easily cause the polymer's color tone to deteriorate, mechanical strength to decrease, and formability to deteriorate.

[0004] CN106928451A discloses a high temperature resistant PA6T copolymer and a preparation method thereof, wherein the raw materials for production mainly include: 100 parts of terephthalic acid, 67-70 parts of hexamethylenediamine, 55-157 parts of aliphatic nylon salt, 0.3-0.55 parts of nucleating agent, 0.1-0.3 parts of catalyst and 160-220 parts of deionized water; the preparation method includes: adding the above components to a reactor, stirring continuously at a stirring speed of 75-150r / min during the reaction process, heating the reactor for the first time, keeping warm, heating for the second time and releasing pressure in sequence under the protection of an inert gas, and then filling the reactor with an inert gas and discharging the material to obtain a high temperature resistant nylon 6T copolymer. However, since the post-condensation process of the method does not involve a decompression stage, the viscosity of the obtained nylon 6T copolymer resin is low, resulting in poor mechanical strength, especially tensile strength, which is only about 50MPa.

[0005] CN111087611A discloses a semi-aromatic high temperature resistant PA6T copolymer and its synthesis method, which is mainly made of the following raw materials in parts by weight: 100 parts of terephthalic acid, 67-70 parts of hexamethylenediamine, 55-157 parts of aliphatic nylon salt, 10-15 parts of isophthalic acid, 0.3-0.55 parts of nucleating agent, 0.1-0.3 parts of catalyst, and 160-220 parts of deionized water. However, its synthesis process includes two processes, prepolymerization and solid phase viscosity enhancement, and the production efficiency is low, and industrial continuous production cannot be achieved.

[0006] In summary, it is urgent to find a high heat-resistant nylon resin and its application with diversified products, easy processing, high mechanical strength, high temperature resistance, low water absorption, and excellent weather resistance, as well as a preparation method of high heat-resistant nylon resin with few by-products, simple production process, and suitable for industrial continuous production. Summary of the invention

[0007] The technical problem to be solved by the present invention is to overcome the above-mentioned defects of the prior art and provide a high heat-resistant nylon resin and its application which has product diversification, is easy to process, has high mechanical strength, high temperature resistance grade, low water absorption and excellent weather resistance.

[0008] The technical problem further to be solved by the present invention is to overcome the above-mentioned defects of the prior art and provide a method for preparing a high heat-resistant nylon resin with less by-products, simple production process and suitable for industrial continuous production.

[0009] The technical solution adopted by the present invention to solve its technical problem is as follows: a high heat-resistant nylon resin is mainly made of the following components: 2,5-di(phenylamino)-1,4-phthalic acid, a linear or branched aliphatic diamine, a catalyst, a capping agent and an anti-yellowing agent, and water is used as the reaction medium.

[0010] The inventive concept of the present invention is as follows: the aromatic diacid 2,5-di(phenylamino)-1,4-phthalic acid containing bulky side groups ensures that the main chain and side chain of the obtained nylon molecule have a high-density benzene ring content, and shows excellent high heat resistance on a macro scale. The presence of bulky side groups can break the tight stacking between molecular chains to a certain extent, and avoid the melting point of the obtained high-heat-resistant nylon resin exceeding its decomposition temperature. By introducing straight-chain or branched aliphatic diamines with different carbon chain lengths, the melting point and mechanical properties of the polymer can be balanced and precisely controlled, and the product performance can be customized to meet specific application sites with different performance requirements.

[0011] Preferably, the molar ratio of the 2,5-di(phenylamino)-1,4-phthalic acid to the linear or branched aliphatic diamine is 1:1.0 to 1.10. When the ratio of the dibasic acid to the diamine is within the above range, the viscosity of the obtained nylon resin is moderate, and the viscosity of the nylon resin is avoided to be low.

[0012] Preferably, the amount of the catalyst, end-capping agent, anti-yellowing agent, and water is 0.09-0.3% (more preferably 0.09-0.2%), 0.3-0.8% (more preferably 0.3-0.5%), 0.1-0.5% (more preferably 0.1-0.3%), and 38-50% of the total mass of 2,5-di(phenylamino)-1,4-phthalic acid and linear or branched aliphatic diamine, respectively. If the amount of the catalyst is too small, the reaction activity of the system may be reduced, thereby affecting the viscosity of the nylon resin; if the amount of the end-capping agent is too large, the viscosity of the nylon resin will be low; if the amount of the anti-yellowing agent is too small, it will be difficult to achieve the expected weather resistance, and if the amount of the anti-yellowing agent is too large, the production cost will increase; if the amount of water is too small, it will be difficult to obtain a clear nylon salt solution, and if the amount of water is too large, when the system reaches a predetermined temperature, the pressure in the system will exceed the standard, posing a safety hazard.

[0013] Preferably, the linear aliphatic diamine includes one or more of 1,6-hexanediamine, 1,8-octanediamine, 1,9-nonanediamine, 1,10-decanediamine, 1,11-undecanediamine or 1,12-dodecanediamine.

[0014] Preferably, the branched aliphatic diamine includes one or more of 2-methyl-1,5-pentanediamine, 3-methyl-1,5-pentanediamine, 2,4-dimethyl-1,6-hexanediamine, 2,2,4-trimethyl-1,6-hexanediamine, 2,4,4-trimethyl-1,6-hexanediamine, 2-methyl-1,8-octanediamine or 5-methyl-1,9-nonanediamine.

[0015] Preferably, the catalyst includes one or more of sodium hypophosphite, potassium hypophosphite, calcium hypophosphite or magnesium hypophosphite, etc. The catalyst can improve the reaction activity to obtain a high heat-resistant nylon resin with a desired relative viscosity.

[0016] Preferably, the end-capping agent includes 4-amino-2,2,6,6-tetramethylpiperidine and / or 4-aminomethyl-2,2,6,6-tetramethylpiperidine, etc. The end-capping agent can adjust the relative viscosity of the high heat-resistant nylon resin to avoid excessive viscosity affecting the melt discharging process. At the same time, introducing such end-capping agents into the ends of the main chains of the high heat-resistant nylon resin molecules can improve its weather resistance.

[0017] Preferably, the anti-yellowing agent includes 1,3,5-trimethyl-2,4,6-(3,5-di-tert-butyl-4-hydroxybenzyl)benzene and / or 3,9-di(2,4-dicumylphenoxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5.5]undecane, etc. The anti-yellowing agent can work synergistically with the end-capping agent to further optimize the weather resistance of the high heat-resistant nylon resin.

[0018] The technical solution adopted by the present invention to further solve the technical problem is as follows: A method for preparing a high heat-resistant nylon resin comprises the following steps: (1) Add 2,5-di(phenylamino)-1,4-phthalic acid, a linear or branched aliphatic diamine and water into a reaction kettle, stir at room temperature to form a salt, and obtain a nylon salt solution; (2) Adding a catalyst, a capping agent and an anti-yellowing agent to the nylon salt solution obtained in step (1), replacing the air in the reaction kettle with an inert gas and filling the reaction kettle with the inert gas, performing a polycondensation reaction, and then filling the reaction kettle with the inert gas and discharging the reaction kettle to obtain a high heat-resistant nylon resin.

[0019] Preferably, in step (2), the specific reaction process of the polycondensation reaction is: firstly carry out a temperature-raising and pressure-maintaining reaction, slowly release the gas and carry out a second temperature-raising and pressure-maintaining reaction, then release the gas to normal pressure, discharge the water in the system, and gradually evacuate the system to carry out a pressure-reducing reaction.

[0020] Preferably, the one-time temperature-raising and pressure-maintaining reaction refers to: raising the temperature to 215-225°C, maintaining the pressure in the kettle at 2.0-2.5MPa (more preferably 2.1-2.4MPa), and reacting for 1.5-2.0h (more preferably 1.7-2.0h). The purpose of the one-time temperature-raising and pressure-maintaining reaction is to perform prepolymerization to obtain a low molecular weight, high heat-resistant nylon resin prepolymer.

[0021] Preferably, the slow release and secondary temperature and pressure maintenance reaction means: continue to heat up to 310-330°C (more preferably 320-330°C), slowly release gas during the heating process to keep the pressure in the kettle at 1.0-1.5MPa (more preferably 1.0-1.3MPa), and react for 1-2h (more preferably 1.2-1.8h). The purpose of the secondary temperature and pressure maintenance reaction is to discharge the water inside the system and slowly increase the molecular weight of the high heat-resistant nylon resin prepolymer.

[0022] Preferably, the stepwise vacuuming means: first vacuuming to -0.01~-0.03MPa, then maintaining the pressure reaction for 10~20min, then vacuuming to -0.03~-0.05MPa, then maintaining the pressure reaction for 10~20min, and finally vacuuming to -0.05~-0.07MPa, then maintaining the pressure reaction for 12~30min. The vacuum degree of the latter vacuuming is greater than the previous one. Before gradually vacuuming, venting to normal pressure can further discharge the moisture inside the system. The purpose of gradual vacuuming is to discharge the moisture generated by the post-condensation process, i.e., the decompression reaction process in the reactor, so that the post-condensation reaction proceeds in the positive direction, thereby further increasing the molecular weight of the high heat-resistant nylon resin; the vacuum degree of the early vacuuming is relatively small, in order to avoid the reaction as violent as possible, resulting in the blockage of the vacuum pipe by the extracted moisture and oligomers, and then gradually increase the vacuum degree to extract as much moisture as possible to obtain the nylon resin with the expected molecular weight.

[0023] More preferably, the stepwise vacuuming means: first vacuuming to -0.01 to -0.02 MPa, then maintaining the pressure for 15 to 20 minutes, then vacuuming to -0.03 to -0.04 MPa, then maintaining the pressure for 15 to 20 minutes, and finally vacuuming to -0.05 to -0.06 MPa, then maintaining the pressure for 20 to 30 minutes.

[0024] Preferably, in step (2), before the polycondensation reaction, the air in the reactor is replaced with an inert gas for 3 to 4 times and the inert gas is filled to 0.1 to 0.2 MPa. The purpose of filling the inert gas is to replace the air in the reactor to prevent the residual air in the reactor from oxidizing the high heat-resistant nylon resin during the high temperature stage, causing the resin to turn yellow.

[0025] Preferably, in step (2), after the polycondensation reaction, an inert gas is charged to a pressure of 0.2 to 0.3 MPa.

[0026] Preferably, in step (2), the inert gas includes one or more of carbon dioxide, nitrogen, argon or helium, etc. The inert gas used in the present invention is a high-purity gas with a purity of ≥99.999%.

[0027] The technical solution adopted by the present invention to further solve its technical problem is as follows: an application of a high heat-resistant nylon resin, wherein the high heat-resistant nylon resin is used in technical fields such as surface mounting, electronic appliances or automobile industry.

[0028] The beneficial effects of the present invention are as follows: (1) The high heat-resistant nylon resin products of the present invention are diversified, easy to process, and have high mechanical strength: relative viscosity up to 2.45, tensile strength up to 89 MPa, flexural strength up to 129 MPa, and notched impact strength up to 11.2 kJ / m 2 , high temperature resistance: melting point up to 323 ℃, initial decomposition temperature up to 401 ℃, water absorption as low as 0.10%, and excellent weather resistance. After 500h UV aging treatment, the yellowness index is between 5 and 8; suitable for surface mounting, electronic appliances or automotive industry and other technical fields; (2) The product obtained by the method of the present invention has few by-products, a simple production process, and is suitable for industrial continuous production. DETAILED DESCRIPTION

[0029] The present invention will be further described below in conjunction with the embodiments.

[0030] 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, are obtained through conventional commercial channels.

[0031] A high heat-resistant nylon resin embodiment 1 to 8 A high heat-resistant nylon resin embodiment 1 to 8 is made of the following components: 2,5-di(phenylamino)-1,4-phthalic acid, a linear or branched aliphatic diamine, a catalyst, a capping agent and an anti-yellowing agent, and water is used as the reaction medium; the components and their amounts are shown in Table 1.

[0032] The components and dosages of Comparative Examples 1 and 2 are shown in Table 1.

[0033] Table 1 Components and dosages of Examples 1 to 8 and Comparative Examples 1 and 2 of the high heat-resistant nylon resin of the present invention

[0034] Note: “ / ” in the table means not added.

[0035] A method for preparing a high heat-resistant nylon resin Example 1 (1) 3.484 kg (10.00 mol) of 2,5-di(phenylamino)-1,4-benzenedicarboxylic acid, 1.168 kg (10.05 mol) of linear aliphatic diamine 1,6-hexanediamine and 1.861 kg (water / (dibasic acid + diamine) = 40%, the same below) of water were added into a reaction kettle and stirred at room temperature to form a salt to obtain a 2,5-di(phenylamino)-1,4-benzenedicarboxylic acid hexanediamine salt (nylon 6-DATA salt) solution; (2) 5.000 g of catalyst sodium hypophosphite, 15.000 g of end-capping agent 4-amino-2,2,6,6-tetramethylpiperidine and 10.000 g of anti-yellowing agent 1,3,5-trimethyl-2,4,6-(3,5-di-tert-butyl-4-hydroxybenzyl)benzene were added to the nylon 6-DATA salt solution obtained in step (1), and the air in the reactor was replaced with high-purity nitrogen for 3 times and filled with inert gas to 0.15 MPa, and then a polycondensation reaction was carried out: first, the temperature was raised to 225°C, and the pressure in the reactor was maintained at 2.4 MPa, and a temperature-raising and pressure-maintaining reaction was carried out for 2.0 h, and then the temperature was continued to be raised to 330°C. During the heating process, the gas was slowly released to maintain the pressure in the reactor at 1.0 MPa, and a second temperature-raising and pressure-maintaining reaction was carried out for 1.5 h later, 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 -0.02MPa, and then maintain the pressure for 15min. Then evacuate the system to -0.04MPa, and then maintain the pressure for 15min. Finally, evacuate the system to -0.06MPa, and then maintain the pressure for 30min. Then, high-purity nitrogen was introduced to 0.3MPa, and the material was released to obtain the high heat-resistant nylon resin Nylon6-DATA.

[0036] A method for preparing a high heat-resistant nylon resin Example 2 (1) 3.484 kg (10.00 mol) of 2,5-di(phenylamino)-1,4-benzenedicarboxylic acid, 1.592 kg (10.06 mol) of linear aliphatic diamine 1,9-nonanediamine and 2.284 kg (45%) of water were added into a reaction kettle and stirred at room temperature to form a salt to obtain a 2,5-di(phenylamino)-1,4-benzenedicarboxylic acid nonanediamine salt (nylon 9-DATA salt) solution; (2) 5.500 g of catalyst sodium hypophosphite, 16.000 g of end-capping agent 4-amino-2,2,6,6-tetramethylpiperidine and 11.000 g of anti-yellowing agent 1,3,5-trimethyl-2,4,6-(3,5-di-tert-butyl-4-hydroxybenzyl)benzene were added to the nylon 9-DATA salt solution obtained in step (1). The air in the reactor was replaced with high-purity nitrogen three times and the inert gas was filled to 0.15 MPa, and then a polycondensation reaction was carried out: first, the temperature was raised to 222° C. and the pressure in the reactor was maintained at 2.3 MPa. A temperature-raising and pressure-maintaining reaction was carried out for 1.8 h. The temperature was further raised to 325° C. During the heating process, the gas was slowly released to maintain the pressure in the reactor at 1.1 MPa. A second temperature-raising and pressure-maintaining reaction was carried out for 1.6 h later, 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 -0.01 MPa, and maintain the pressure for 17 min. Then, evacuate the system to -0.03 MPa, and maintain the pressure for 17 min. Finally, evacuate the system to -0.06 MPa, and maintain the pressure for 30 min. High-purity nitrogen was then introduced to 0.3 MPa, and the material was released to obtain the high heat-resistant nylon resin Nylon9-DATA.

[0037] A method for preparing a high heat-resistant nylon resin Example 3 (1) 3.484 kg (10.00 mol) of 2,5-di(phenylamino)-1,4-benzenedicarboxylic acid, 1.735 kg (10.07 mol) of linear aliphatic diamine 1,10-decanediamine and 2.349 kg (45%) of water were added into a reaction kettle and stirred at room temperature to form a salt to obtain a 2,5-di(phenylamino)-1,4-benzenedicarboxylic acid decanediamin salt (nylon 10-DATA salt) solution; (2) 6.000 g of catalyst sodium hypophosphite, 16.500 g of end-capping agent 4-amino-2,2,6,6-tetramethylpiperidine and 12.000 g of anti-yellowing agent 1,3,5-trimethyl-2,4,6-(3,5-di-tert-butyl-4-hydroxybenzyl)benzene were added to the nylon 10-DATA salt solution obtained in step (1), and the air in the reactor was replaced with high-purity nitrogen for 3 times and filled with inert gas to 0.15 MPa, and then a polycondensation reaction was carried out: first, the temperature was raised to 220°C, and the pressure in the reactor was maintained at 2.2 MPa, and a temperature-raising and pressure-maintaining reaction was carried out for 2.0 h, and then the temperature was continued to be raised to 320°C. During the heating process, the gas was slowly released to maintain the pressure in the reactor at 1.0 MPa, and a second temperature-raising and pressure-maintaining reaction was carried out for 1.8 h later, 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 -0.02MPa, and then maintain the pressure for 18min. Then, evacuate the system to -0.04MPa, and then maintain the pressure for 18min. Finally, evacuate the system to -0.06MPa, and then maintain the pressure for 25min. Then, high-purity nitrogen was introduced to 0.3MPa, and the material was released to obtain the high heat-resistant nylon resin Nylon10-DATA.

[0038] A method for preparing a high heat-resistant nylon resin Example 4 (1) 3.484 kg (10.00 mol) of 2,5-di(phenylamino)-1,4-benzenedicarboxylic acid, 1.878 kg (10.08 mol) of linear aliphatic diamine 1,11-undecanediamine and 2.413 kg (45%) of water were added into a reaction kettle and stirred at room temperature to form a salt to obtain a 2,5-di(phenylamino)-1,4-benzenedicarboxylic acid undecanediamine salt (nylon 11-DATA salt) solution; (2) 6.000 g of catalyst sodium hypophosphite, 16.500 g of end-capping agent 4-amino-2,2,6,6-tetramethylpiperidine and 15.000 g of anti-yellowing agent 1,3,5-trimethyl-2,4,6-(3,5-di-tert-butyl-4-hydroxybenzyl)benzene were added to the nylon 11-DATA salt solution obtained in step (1), and the air in the reactor was replaced with high-purity nitrogen for 3 times and filled with inert gas to 0.15 MPa, and then a polycondensation reaction was carried out: first, the temperature was raised to 218°C, and the pressure in the reactor was maintained at 2.1 MPa, and a temperature-raising and pressure-maintaining reaction was carried out for 2.0 h, and then the temperature was continued to be raised to 320°C. During the heating process, the gas was slowly released to maintain the pressure in the reactor at 1.0 MPa, and a second temperature-raising and pressure-maintaining reaction was carried out for 1.5 h later, release the air to make the pressure in the reactor return to normal pressure, discharge the water in the system, and use a vacuum pump to gradually evacuate the system for a reduced pressure reaction: first evacuate the system to -0.01MPa, maintain the pressure for 20min, then evacuate the system to -0.03MPa, maintain the pressure for 20min, and finally evacuate the system to -0.05MPa, maintain the pressure for 30min, then fill in high-purity nitrogen to 0.3MPa, release the material, and obtain the high heat-resistant nylon resin Nylon11-DATA.

[0039] A method for preparing a high heat-resistant nylon resin Example 5 (1) 3.484 kg (10.00 mol) of 2,5-di(phenylamino)-1,4-benzenedicarboxylic acid, 2.024 kg (10.10 mol) of linear aliphatic diamine 1,12-dodecanediamine and 2.754 kg (50%) of water were added into a reaction kettle and stirred at room temperature to form a salt to obtain a 2,5-di(phenylamino)-1,4-benzenedicarboxylic acid dodecanediamine salt (nylon 12-DATA salt) solution; (2) 6.000 g of catalyst sodium hypophosphite, 17.000 g of end-capping agent 4-amino-2,2,6,6-tetramethylpiperidine and 10.000 g of anti-yellowing agent 3,9-di(2,4-dicumylphenoxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5.5]undecane were added to the nylon 12-DATA salt solution obtained in step (1), and the air in the reactor was replaced with high-purity nitrogen three times and filled with inert gas to 0.15 MPa, and then a polycondensation reaction was carried out: first, the temperature was raised to 215° C. and the pressure in the reactor was maintained at 2.3 MPa, and a temperature-raising and pressure-maintaining reaction was carried out for 2.0 h, and then the temperature was continued to be raised to 320° C., and the gas was slowly released during the heating process to maintain the pressure in the reactor at 1.0 MPa, and a second temperature-raising and pressure-maintaining reaction was carried out for 1.8 h later, release the air to make the pressure in the reactor return to normal pressure, discharge the water in the system, and use a vacuum pump to gradually evacuate the system for a reduced pressure reaction: first evacuate to -0.02MPa, maintain the pressure for 15min, then evacuate to -0.04MPa, maintain the pressure for 15min, and finally evacuate to -0.06MPa, maintain the pressure for 30min, then fill in high-purity nitrogen to 0.3MPa, release the material, and obtain the high heat-resistant nylon resin Nylon12-DATA.

[0040] A method for preparing a high heat-resistant nylon resin Example 6 (1) 3.484 kg (10.00 mol) of 2,5-di(phenylamino)-1,4-benzenedicarboxylic acid, 1.174 kg (10.10 mol) of branched aliphatic diamine 2-methyl-1,5-pentanediamine (DytekA) and 1.863 kg (40%) of water were added into a reaction kettle and stirred at room temperature to form a salt to obtain a 2,5-di(phenylamino)-1,4-benzenedicarboxylic acid 2-methyl-1,5-pentanediamine salt (nylon DytekA-DATA salt) solution; (2) 5.000 g of catalyst calcium hypophosphite, 16.000 g of end-capping agent 4-aminomethyl-2,2,6,6-tetramethylpiperidine and 12.000 g of anti-yellowing agent 3,9-di(2,4-dicumylphenoxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5.5]undecane were added to the nylon Dytek A-DATA salt solution obtained in step (1), and the subsequent operation was the same as step (2) of method example 1, and finally a high heat-resistant nylon resin Nylon Dytek A-DATA was obtained.

[0041] A method for preparing a high heat-resistant nylon resin Example 7 (1) 3.484 kg (10.00 mol) of 2,5-di(phenylamino)-1,4-benzenedicarboxylic acid, 1.615 kg (10.20 mol) of branched aliphatic diamine 2,2,4-trimethyl-1,6-hexanediamine (2,2,4-TMHA) and 2.040 kg (40%) of water were added into a reaction kettle and stirred at room temperature to form a salt to obtain a solution of 2,5-di(phenylamino)-1,4-benzenedicarboxylic acid 2,2,4-trimethyl-1,6-hexanediamine salt (nylon 2,2,4-TMHA-DATA salt); (2) 5.000 g of catalyst calcium hypophosphite, 16.500 g of end-capping agent 4-aminomethyl-2,2,6,6-tetramethylpiperidine and 15.000 g of anti-yellowing agent 3,9-di(2,4-dicumylphenoxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5.5]undecane were added to the nylon 2,2,4-TMHA-DATA salt solution obtained in step (1), and the subsequent operation was the same as step (2) of method example 1, and finally a high heat-resistant nylon resin Nylon2,2,4-TMHA-DATA was obtained.

[0042] Example 8 of a method for preparing a high heat-resistant nylon resin (1) 3.484 kg (10.00 mol) of 2,5-di(phenylamino)-1,4-benzenedicarboxylic acid, 1.731 kg (10.94 mol) of branched aliphatic diamine 5-methyl-1,9-nonanediamine and 2.347 kg (45%) of water were added into a reaction kettle and stirred at room temperature to form a salt to obtain a 2,5-di(phenylamino)-1,4-benzenedicarboxylic acid 5-methyl-1,9-nonanediamine salt (nylon 5-M-9-DATA salt) solution; (2) 5.500 g of catalyst potassium hypophosphite, 25.000 g of end-capping agent 4-aminomethyl-2,2,6,6-tetramethylpiperidine and 15.000 g of anti-yellowing agent 3,9-di(2,4-dicumylphenoxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5.5]undecane were added to the nylon 5-M-9-DATA salt solution obtained in step (1), and the subsequent operation was the same as step (2) of method example 2, and finally a high heat-resistant nylon resin Nylon5-M-9-DATA was obtained.

[0043] Application Examples 1 to 8 of a High Heat Resistant Nylon Resin The high heat-resistant nylon resin embodiments 1 to 8 are respectively used in the field of surface mounting, electronic appliances or automobile industry technology.

[0044] Comparative Example 1 (1) 1.661 kg (10.00 mol) of terephthalic acid, 1.591 kg (10.05 mol) of 1,9-nonanediamine and 1.463 kg (45%) of water were added into a reaction kettle and stirred at room temperature to form a salt to obtain a nylon 9T salt solution; (2) Add 5.000 g of catalyst potassium hypophosphite and 15.000 g of end-capping agent benzoic acid to the nylon 9T salt solution obtained in step (1), and perform the subsequent operation in the same manner as step (2) of method example 2 to finally obtain high heat-resistant nylon resin Nylon 9T.

[0045] Comparative Example 2 (1) Same as step (1) in Example 2; (2) 5.500 g of catalyst sodium hypophosphite and 16.000 g of end-capping agent 4-amino-2,2,6,6-tetramethylpiperidine were added to the nylon 9-DATA salt solution obtained in step (1), and the subsequent operation was the same as step (2) of method example 2 to finally obtain high heat-resistant nylon resin Nylon 9-DATA.

[0046] Comparative Example 3 The difference between this comparative example and method example 2 is that: in step (2), polycondensation reaction: firstly, the temperature is raised to 222°C, and the pressure in the kettle is maintained at 2.3 MPa, and a temperature-raising and pressure-maintaining reaction is carried out for 0.9 h, and then the temperature is further raised to 325°C, and the gas is slowly released during the temperature-raising process to maintain the pressure in the kettle at 1.1 MPa, and a second temperature-raising and pressure-maintaining reaction is carried out for 0.8 h, and then the pressure in the reaction kettle is released to normal pressure, and after the water in the system is discharged, a vacuum pump is used for a decompression reaction: after vacuuming to -0.05 MPa, the pressure is maintained for 30 min, and then high-purity nitrogen is charged to 0.3 MPa, and the material is discharged to obtain a low-viscosity, high-heat-resistant nylon resin Nylon9-DATA. The rest is the same as method example 2.

[0047] In order to evaluate the relative viscosity, mechanical properties, heat resistance and water absorption properties of high heat-resistant nylon resin embodiments 1 to 8 and comparative examples 1 to 3 of the present invention, the tests were carried out according to the following test conditions: Relative viscosity test conditions: The samples of the embodiment and the comparative example were placed in a vacuum drying oven at 120° C. for 4 h, and prepared into a concentrated sulfuric acid solution with a concentration of 0.010 g / mL, and tested using an automatic viscometer in accordance with 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 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; Notched 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 samples of the embodiments and comparative examples, and heat the samples to 340°C for 3 min under the protection of high-purity nitrogen, quench with liquid nitrogen, and then heat the quenched samples to 350°C, cool to room temperature, and then heat to 350°C, with a heating rate of 10°C / min, referring to standard GB / T 19466.3-2004; Initial decomposition temperature test conditions: weigh 3-8 mg of the samples of the embodiments and comparative examples, and heat the samples to 700°C under the protection of high-purity nitrogen. The temperature corresponding to 5% weight loss is the initial decomposition temperature, refer to standard GB / T 33047.1-2016; Water absorption test conditions: The samples of the embodiment and the comparative example were dried in an oven at 100°C, cooled in the oven, and tested according to the standard ASTM D570-98; Yellowness index test conditions: After the samples of the embodiment and comparative example were subjected to 500 hours of UV aging, the yellowness index was measured according to the standard GB / T 2409-1980; The results are shown in Table 2.

[0048] Table 2 Comparison of relevant performance data of high heat resistant nylon resin examples 1 to 8 and comparative examples 1 to 3 of the present invention

[0049] As shown in Table 2, the high heat-resistant nylon resin embodiments 1 to 8 of the present invention have diversified products, are easy to process, have high mechanical strength, have a relative viscosity of up to 2.45, a tensile strength of up to 89 MPa, a flexural strength of up to 129 MPa, and a notched impact strength of up to 11.2 kJ / m 2, high temperature resistance: melting point up to 323 ℃, initial decomposition temperature up to 401 ℃, water absorption rate as low as 0.10%, and excellent weather resistance. After 500h UV aging treatment, the yellowness index is between 5 and 8. Comparative Example 1 uses terephthalic acid as the diacid, and the melting point of the obtained high heat-resistant nylon resin Nylon9T is 308 ℃. Compared with Comparative Example 1, the diacid used in Example 2 is 2,5-di(phenylamino)-1,4-phthalic acid, and the melting point of the obtained high heat-resistant nylon resin Nylon9-DATA is 301 ℃. First, this reduces the high melting point of the high heat-resistant nylon resin to a certain extent and improves its processing performance. On the other hand, the mechanical strength of Nylon9-DATA is significantly better than that of Nylon9T, and the yellowness index and water absorption rate are further improved. Compared with Example 2, since no anti-yellowing agent is added, no synergistic effect is formed in the system, and its yellowness index is significantly increased to 14, and the weather resistance is significantly reduced. Compared with Example 2, due to the different polycondensation reaction processes, the relative viscosity of the obtained high heat-resistant nylon resin Nylon9-DATA is lower, and the comprehensive performance parameters are all reduced. The high heat-resistant nylon resin of the present invention is suitable for surface mounting, electronic appliances or automotive industry and other technical fields due to its excellent mechanical strength, heat resistance, low water absorption and weather resistance.

Claims

1. A high heat-resistant nylon resin, characterized in that: The invention is mainly prepared from the following components: 2,5-di(phenylamino)-1,4-phthalic acid, straight-chain or branched-chain aliphatic diamine, catalyst, end-capping agent and anti-yellowing agent, and water is used as the reaction medium.

2. The high heat-resistant nylon resin according to claim 1, characterized in that: The molar ratio of the 2,5-di(phenylamino)-1,4-phthalic acid to the linear or branched aliphatic diamine is 1:1.0-1.10; the amounts of the catalyst, the end-capping agent, the anti-yellowing agent and the water are 0.09-0.3%, 0.3-0.8%, 0.1-0.5% and 38-50% of the total mass of the 2,5-di(phenylamino)-1,4-phthalic acid and the linear or branched aliphatic diamine, respectively.

3. The high heat-resistant nylon resin according to claim 1 or 2, characterized in that: The linear aliphatic diamine includes one or more of 1,6-hexanediamine, 1,8-octanediamine, 1,9-nonanediamine, 1,10-decanediamine, 1,11-undecanediamine or 1,12-dodecanediamine; the branched aliphatic diamine includes 2-methyl-1,5-pentanediamine, 3-methyl-1,5-pentanediamine, 2,4-dimethyl-1,6-hexanediamine, 2,2,4-trimethyl-1,6-hexanediamine, 2,4,4-trimethyl-1,6-hexanediamine, 2-methyl-1,8-octanediamine or 5-methyl-1,9-nonanediamine. The invention relates to a method for preparing an alkyl iodine-containing compound of claim 1 , wherein the alkyl iodine comprises one or more of diamines; the catalyst comprises one or more of sodium hypophosphite, potassium hypophosphite, calcium hypophosphite or magnesium hypophosphite; the end-capping agent comprises 4-amino-2,2,6,6-tetramethylpiperidine and / or 4-aminomethyl-2,2,6,6-tetramethylpiperidine; the anti-yellowing agent comprises 1,3,5-trimethyl-2,4,6-(3,5-di-tert-butyl-4-hydroxybenzyl)benzene and / or 3,9-bis(2,4-dicumylphenoxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro[5.5]undecane.

4. A method for preparing a high heat-resistant nylon resin as claimed in any one of claims 1 to 3, characterized in that: The following steps are involved: (1) Add 2,5-di(phenylamino)-1,4-phthalic acid, a linear or branched aliphatic diamine and water into a reaction kettle, stir at room temperature to form a salt, and obtain a nylon salt solution; (2) Adding a catalyst, a capping agent and an anti-yellowing agent to the nylon salt solution obtained in step (1), replacing the air in the reaction kettle with an inert gas and filling the reaction kettle with the inert gas, performing a polycondensation reaction, and then filling the reaction kettle with the inert gas and discharging the reaction kettle to obtain a high heat-resistant nylon resin.

5. The method for preparing the high heat-resistant nylon resin according to claim 4, characterized in that: In step (2), the specific reaction process of the polycondensation reaction is: firstly carry out a temperature-raising and pressure-maintaining reaction, slowly release the gas and carry out a second temperature-raising and pressure-maintaining reaction, then release the gas to normal pressure, discharge the water in the system, and gradually evacuate the system to carry out a pressure-reducing reaction; the first temperature-raising and pressure-maintaining reaction refers to: heating to 215-225°C, and maintaining the pressure in the autoclave at 2.0-2.5MPa, and reacting for 1.5-2.0h; the slow release and second temperature-raising and pressure-maintaining reaction refers to: continuing to heat to 310-330°C, slowly releasing the gas during the heating process to maintain the pressure in the autoclave at 1.0-1.5MPa, and reacting for 1-2h; the gradual extraction Vacuum means: first evacuate to -0.01~-0.03MPa, then maintain the pressure for 10~20min, then evacuate to -0.03~-0.05MPa, then maintain the pressure for 10~20min, finally evacuate to -0.05~-0.07MPa, then maintain the pressure for 12~30min; before the polycondensation reaction, replace the air in the reaction kettle with inert gas 3~4 times and fill it with inert gas to 0.1~0.2MPa; after the polycondensation reaction, fill it with inert gas to 0.2~0.3MPa; the inert gas includes one or more of carbon dioxide, nitrogen, argon or helium.

6. An application of the high heat-resistant nylon resin as claimed in any one of claims 1 to 3, characterized in that: The high heat-resistant nylon resin according to any one of claims 1 to 3 is used in the field of surface mounting, electronic appliances or automobile industry technology.

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