A high temperature resistant nylon block copolymer and a method for preparing the same

Abstract

The application discloses a kind of high-temperature-resistant nylon block copolymer and preparation method thereof, belong to high-temperature-resistant nylon technical field.The application provides preparation method including steps: binary acid, binary amine, antioxidant, end-capping agent, catalyst are added in water, after being mixed uniformly, salt making reaction is carried out, obtain salt solution;Salt solution is added into polymerization kettle, and a certain amount of PA56 or PA66 / PA6 copolymer is added, air in polymerization kettle is replaced into protective gas, and then heating is carried out, when pressure reaches 2.4-3.0MPa, pressure maintaining is carried out, when temperature reaches 240-260 DEG C, pre-polymerization is carried out for 1-3 hours, continue to heat to 280-300 DEG C, and then pressure relief is carried out to normal pressure, and the target product is obtained after discharging and pelletizing.The high-temperature-resistant nylon block copolymer with good appearance, stable product performance and good toughness is prepared by improving the preparation process.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of high-temperature-resistant nylon and particularly relates to a high-temperature-resistant nylon block copolymer and a preparation method thereof. BACKGROUND

[0002] Since the melting point of the high-temperature-resistant nylon is relatively high, the polymerization threshold is relatively high, the heat medium is easy to degrade during polymerization, the polymer appearance is easy to turn yellow, and the like. Meanwhile, the melting point of the high-temperature-resistant nylon salt is relatively high, the solubility in the aqueous solution is relatively low, the solution is crystallized and caked during the heating process, the proportion in the polymerizer is imbalanced, the uniformity of the product is finally affected, and the material retention in the polymerizer is serious in severe cases.

[0003] Patent with publication number CN104774454A discloses a high-temperature-resistant nylon PA66T material and a preparation method thereof. The patent directly adds the dried nylon 6T salt and PA66 for high-pressure polymerization reaction, and the PA6T / 66 high-temperature-resistant nylon material is prepared by the melting method. Since the polymerization temperature is relatively high, the material appearance turns yellow, and the precipitation of the high-temperature-resistant nylon salt during the heating stage causes the product to have nodular materials and the discharge to be not smooth.

[0004] In the high-temperature-resistant nylon copolymer reported in the current patent, mainly PA66 copolymerization or copolymerization with PA6I, the high-temperature-resistant nylon prepared by the one-step melting polymerization method generally has the problems of yellow appearance, unsmooth discharge, and the like. Since the copolymerization with PA66, the carboxyl group of adipic acid is easy to decarboxylate, the material is easy to turn yellow, and the nodular materials appear, the discharge is not smooth, and the slivers are easy to break; in addition, the nylon material produced by the prior art also has the defects of poor toughness and low elongation at break. SUMMARY

[0005] In view of the problems in the production process of the high-temperature-resistant nylon copolymer in the prior art, the purpose of the application is to provide a high-temperature-resistant nylon block copolymer and a preparation method thereof. The high-temperature-resistant nylon material with good appearance, stable product performance, good toughness, and easy modification and processing is prepared by improving the synthesis process.

[0006] To achieve the above purpose, the technical scheme adopted by the application is as follows:

[0007] A preparation method of a high-temperature-resistant nylon block copolymer, comprising the following steps:

[0008] The binary acid, the binary amine, the antioxidant, the end-capping agent and the catalyst are added into water, mixed uniformly, and then a salt reaction is carried out to obtain a salt solution; preferably, the molar ratio of the binary acid to the binary amine is (0.98-1.05):1; the amounts of the antioxidant, the end-capping agent and the catalyst are 0.01-1%, 1-3% and 0.01-1% respectively based on the total mass of the binary acid and the binary amine; water serves as a solvent, and the amount of water can be determined according to the need of fully dispersing the reaction raw materials; preferably, the mass of water is the same as the total mass of the reaction raw materials.

[0009] The salt solution is added into a polymerization kettle, and 20-40% of PA56 or PA66 / PA6 copolymer resin based on the total mass of the materials is added; air in the polymerization kettle is replaced by a protective gas, and then the temperature is raised; when the pressure reaches 2.4-3.0 MPa, pressure maintaining is carried out; when the temperature reaches 240-260℃, pre-polymerization is carried out for 1-3 hours; the temperature is continuously raised to 280-300℃, and then pressure maintaining is carried out for 1-3 hours; then the temperature is continuously raised to 320℃, and the pressure is released to normal pressure; the product is discharged and granulated to obtain a high-temperature-resistant nylon block copolymer. Preferably, the protective gas is nitrogen or an inert gas. In the present application, the melting point of the high-temperature-resistant nylon is adjusted by controlling the amount of PA56 or PA66 / PA6 copolymer added, and therefore the amount of PA56 or PA66 / PA6 copolymer added has a great influence on the performance of the product; when the amount of PA56 or PA66 / PA6 copolymer added is too low, the melting point of the high-temperature-resistant nylon is relatively high, and the high-temperature-resistant nylon is not easy to process; when the amount of PA56 or PA66 / PA6 copolymer added is too high, the melting point of the high-temperature-resistant nylon is relatively low, and the high-temperature-resistant nylon does not have the advantages of high-temperature-resistant nylon, and the temperature resistance is relatively poor.

[0010] As a preferred technical solution, the temperature of the salt reaction is 105-160℃, and more preferably 120-150℃; the reaction time is 1-3 hours, and more preferably 1.5-2.5 hours.

[0011] As a preferred technical solution, the relative viscosity of the PA56 or PA66 / PA6 copolymer resin is 2.0-2.7, and more preferably the relative viscosity is 2.4-2.6.

[0012] As a preferred technical solution, the binary acid is an aromatic binary acid. Further preferably, the aromatic binary acid is at least one of terephthalic acid and isophthalic acid.

[0013] As a preferred technical solution, the binary amine is an aliphatic diamine. Further preferably, the aliphatic diamine is at least one of butanediamine, pentanediamine, hexanediamine, nonanediamine, decanediamine, dodecanediamine and dimethylpentanediamine.

[0014] Preferably, the antioxidant is at least one of beta-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid n-octadecyl ester, N,N-bis-(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl)hexylenediamine, and tris[2,4-di-tert-butylphenyl] phosphite.

[0015] Preferably, the end-capping agent is at least one of benzoic acid, acetic acid, propionic acid, and phthalic anhydride.

[0016] Preferably, the catalyst is at least one of sodium phosphate, magnesium phosphate, calcium phosphate, sodium phosphite, magnesium phosphite, calcium phosphite, zinc phosphite, sodium hypophosphite, magnesium hypophosphite, calcium hypophosphite, and zinc hypophosphite.

[0017] The present application also provides a high-temperature-resistant nylon block copolymer prepared by the above method.

[0018] Compared with the prior art, the present application has the following advantages:

[0019] In the preparation of the high-temperature-resistant nylon block copolymer, a salt-making reaction is first performed, and then the obtained salt solution is subjected to a high-temperature high-pressure reaction with PA56 or PA66 / PA6 copolymer resin. PA56 or PA66 / PA6 copolymer will be chain-broken and rearranged in the high-temperature aqueous solvent, and the resin has higher stability and better material uniformity, and the product has better appearance, is stable and easy to modify and process. DETAILED DESCRIPTION

[0020] The present application will be further described below in conjunction with examples so that those skilled in the art can better understand the present application and implement it. However, the examples are not intended to limit the present application.

[0021] In addition, in the preparation process in the following examples, if not specifically stated, it is a conventional means in the prior art in the art, and therefore, will not be described in detail.

[0022] Comparative Example 1

[0023] A preparation method of a high-temperature-resistant nylon copolymer includes the following steps:

[0024] Take 2696g hexanediamine, 2203g terephthalic acid, 1586g adipic acid, 10g tri[2,4-di-tert-butylphenyl] phosphite, 100g benzoic acid and 10g sodium phosphite into the polymerization kettle to carry out salt making reaction, the reaction temperature is 120℃, and the reaction time is 1.5 hours;

[0025] The salt solution generated by the reaction is pumped into the polymerization kettle, the air in the polymerization kettle is replaced by nitrogen, then the temperature is raised, the pressure is kept to 2.6MPa after the temperature reaches 240℃, the prepolymerization reaction is carried out for 1.5 hours, the temperature is continuously raised to 290℃, the temperature is kept for 1.5 hours, then the temperature is continuously raised to 320℃, the pressure is released to normal pressure, and the high-temperature resistant nylon block copolymer can be obtained by discharging and granulating.

[0026] Comparative Example 2

[0027] A preparation method of a high-temperature resistant nylon copolymer, comprising the following steps:

[0028] Take 1435g hexanediamine, 1106g pentanediamine, 2203g terephthalic acid, 1586g adipic acid, 10g tri[2,4-di-tert-butylphenyl] phosphite, 100g benzoic acid and 10g sodium phosphite into the polymerization kettle to carry out salt making reaction, the reaction temperature is 120℃, and the reaction time is 1.5 hours;

[0029] The salt solution generated by the reaction is pumped into the polymerization kettle, the air in the polymerization kettle is replaced by nitrogen, then the temperature is raised, the pressure is kept to 2.6MPa after the temperature reaches 240℃, the prepolymerization reaction is carried out for 1.5 hours, the temperature is continuously raised to 290℃, the temperature is kept for 1.5 hours, then the temperature is continuously raised to 320℃, the pressure is released to normal pressure, and the high-temperature resistant nylon block copolymer can be obtained by discharging and granulating.

[0030] Comparative Example 3

[0031] A preparation method of a high-temperature resistant nylon block copolymer, comprising the following steps:

[0032] Take 2696g hexanediamine, 3850g terephthalic acid, 10g tri[2,4-di-tert-butylphenyl] phosphite, 100g benzoic acid and 10g sodium phosphite into the polymerization kettle to carry out salt making reaction, the reaction temperature is 120℃, and the reaction time is 1.5 hours;

[0033] The salt solution generated by the reaction is pumped into the polymerization kettle, and 1860g PA56 resin with a relative viscosity of 2.5 is added;

[0034] The air in the polymerization kettle is replaced by nitrogen, and the temperature is raised. After the pressure reaches 2.6 MPa, pressure maintaining is performed. The temperature is raised to 290 DEG C for 1.5 hours of pressure maintaining. After the pressure maintaining is completed, the temperature is continuously raised to 320 DEG C. The pressure is released to normal pressure. The material is discharged and granulated to obtain the high-temperature-resistant nylon block copolymer.

[0035] Example 1

[0036] A preparation method of a high-temperature-resistant nylon block copolymer comprises the following steps:

[0037] 2696 g of hexanediamine, 3850 g of terephthalic acid, 10 g of tris[2,4-di-tert-butylphenyl] phosphite, 100 g of benzoic acid, and 10 g of sodium phosphite are weighed and added to a polymerization kettle for salt-making reaction. The reaction temperature is 120 DEG C, and the reaction time is 1.5 hours.

[0038] The salt solution generated in the reaction is pumped into the polymerization kettle, and 1860 g of PA56 resin with a relative viscosity of 2.5 is added.

[0039] The air in the polymerization kettle is replaced by nitrogen, and the temperature is raised. After the pressure reaches 2.6 MPa, pressure maintaining is performed. The temperature is raised to 240 DEG C for 1.5 hours of pre-polymerization. The temperature is continuously raised to 290 DEG C for 1.5 hours of pressure maintaining. After the pressure maintaining is completed, the temperature is continuously raised to 320 DEG C. The pressure is released to normal pressure. The material is discharged and granulated to obtain the high-temperature-resistant nylon block copolymer.

[0040] Example 2

[0041] A preparation method of a high-temperature-resistant nylon block copolymer comprises the following steps:

[0042] 2696 g of hexanediamine, 3850 g of terephthalic acid, 10 g of tris[2,4-di-tert-butylphenyl] phosphite, 100 g of benzoic acid, and 10 g of sodium phosphite are weighed and added to a polymerization kettle for salt-making reaction. The reaction temperature is 120 DEG C, and the reaction time is 1.5 hours.

[0043] The salt solution generated in the reaction is pumped into the polymerization kettle, and 1860 g of PA56 resin with a relative viscosity of 2.5 is added.

[0044] The air in the polymerization kettle is replaced by nitrogen, and the temperature is raised. After the pressure reaches 2.6 MPa, pressure maintaining is performed. The temperature is raised to 240 DEG C for 1.5 hours of pre-polymerization. The temperature is continuously raised to 290 DEG C for 1.5 hours of pressure maintaining. After the pressure maintaining is completed, the temperature is continuously raised to 320 DEG C. The pressure is released to normal pressure. The material is discharged and granulated to obtain the high-temperature-resistant nylon block copolymer.

[0045] Example 3

[0046] A preparation method of a high-temperature-resistant nylon block copolymer comprises the following steps:

[0047] Take 2696g hexanediamine, 3880g terephthalic acid, 15g tris[2,4-di-tert-butylphenyl] phosphite, 80g benzoic acid and 5g sodium phosphite into the polymerization kettle for salt making reaction, the reaction temperature is 130℃, and the reaction time is 3 hours;

[0048] Pump the salt solution generated by the reaction into the polymerization kettle, and add 1800g PA66 / PA6 copolymer resin with a relative viscosity of 2.5;

[0049] Replace the air in the polymerization kettle with nitrogen, heat, and after the pressure reaches 2.6MPa, keep the pressure, when the temperature reaches 260℃, carry out prepolymerization for 1 hour, continue to heat to 290℃, keep the temperature and pressure for 1.5 hours, after the temperature and pressure keeping is finished, continue to heat to 320℃, release the pressure to normal pressure, discharge and granulate to obtain the high-temperature-resistant nylon block copolymer.

[0050] Example 4

[0051] A method for preparing a high-temperature-resistant nylon block copolymer, comprising the following steps:

[0052] Take 2750g hexanediamine, 3850g terephthalic acid, 10g tris[2,4-di-tert-butylphenyl] phosphite, 100g benzoic acid and 10g sodium phosphite into the polymerization kettle for salt making reaction, the reaction temperature is 120℃, and the reaction time is 2 hours;

[0053] Pump the salt solution generated by the reaction into the polymerization kettle, and add 2000g PA66 / PA6 copolymer resin with a relative viscosity of 2.5;

[0054] Replace the air in the polymerization kettle with nitrogen, heat, and after the pressure reaches 2.6MPa, keep the pressure, when the temperature reaches 250℃, carry out prepolymerization for 3 hours, continue to heat to 290℃, keep the temperature and pressure for 1.5 hours, after the temperature and pressure keeping is finished, continue to heat to 320℃, release the pressure to normal pressure, discharge and granulate to obtain the high-temperature-resistant nylon block copolymer.

[0055] Example 5

[0056] A method for preparing a high-temperature-resistant nylon block copolymer, comprising the following steps:

[0057] Take 2696g hexanediamine, 3850g terephthalic acid, 10g tris[2,4-di-tert-butylphenyl] phosphite, 150g benzoic acid and 10g sodium phosphite into the polymerization kettle for salt making reaction, the reaction temperature is 120℃, and the reaction time is 1.5 hours;

[0058] Pump the salt solution generated by the reaction into the polymerization kettle, and add 1860g PA56 resin with a relative viscosity of 2.5;

[0059] The air in the polymerization kettle is replaced by nitrogen, heated, and the pressure is maintained to 2.6 MPa. When the temperature reaches 245℃, the prepolymerization reaction is carried out for 2.5 hours. Continue to heat to 290℃ and maintain pressure for 1.5 hours. After maintaining pressure, continue to heat to 320℃, depressurize to normal pressure, discharge and granulate to obtain a high-temperature-resistant nylon block copolymer.

[0060] The products prepared in the above respective comparative examples and examples are tested for performance, wherein the tensile strength is tested according to standard ISO 527-1-2019, the tensile modulus is tested according to standard ISO 527-1-2019, the bending strength is tested according to standard ISO 178-2019, the notched Charpy impact strength is tested according to standard ISO 179-1-2023, the melting point is tested according to standard ISO 1133, and the yellow index is tested according to standard ISO 17223; the test results are shown in Table 1 below:

[0061] Table 1

[0062]

[0063] As can be seen from Table 1, the high-temperature-resistant nylon block copolymer prepared in the examples of the present application has a more optimal appearance, and the yellow index is within 10. However, the conventional high-temperature-resistant nylon copolymer has PA66 salt, and the carboxyl group of adipic acid is not resistant to temperature and is prone to decarboxylation, resulting in yellow material. In addition, the process provided by the present application is to first perform semi-aromatic nylon prepolymerization at 240-260℃, and then perform aliphatic nylon chain extension at 280-300℃. After depressurization at 320℃, the high-temperature-resistant nylon prepolymer and the low molecular weight aliphatic nylon after chain scission are subjected to polycondensation to form a block copolymer. As can be seen from the comparison between Example 1 and Comparative Example 3, the product prepared by the process of the present application has better performance. The high-temperature-resistant nylon block copolymer prepared by the present application not only retains the high strength and high modulus of semi-aromatic nylon, but also has the toughness of aliphatic nylon, and has a high elongation at break.

[0064] It is obvious to a person skilled in the art that the present application is not limited to the details of the above exemplary embodiments, but can be implemented in other specific forms without departing from the spirit or essential characteristics of the present application. Therefore, the examples should be considered exemplary and non-limiting in any respect, and the scope of the present application is defined by the appended claims rather than the above description, and all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be encompassed by the present application.

[0065] Furthermore, it should be understood that although the specification is described in terms of embodiments, not every embodiment includes every feature or implementation described herein. The specification can include implicit combinations of explicitly mentioned features and / or implicit combinations of implicitly mentioned features. Such combinations are also expressly included within the scope of the specification and an embodiment.

Claims

1. A process for the preparation of a high temperature resistant nylon block copolymer characterized by: Includes the following steps: Dicarboxylic acid, diamine, antioxidant, capping agent, and catalyst are added to water, mixed evenly, and then a salt-making reaction is carried out to obtain a salt solution. Add the salt solution to the polymerization reactor, and add 20-40% of PA56 or PA66 / PA6 copolymer resin by weight of the total material. Replace the air in the polymerization reactor with a protective gas and then raise the temperature. When the pressure reaches 2.4-3.0 MPa, maintain the pressure and carry out the prepolymerization reaction for 1-3 hours at 240-260℃. Continue to raise the temperature to 280-300℃ and maintain the temperature and pressure for 1-3 hours. Then continue to raise the temperature to 320℃, release the pressure to atmospheric pressure, discharge the material, and granulate to obtain the high-temperature resistant nylon block copolymer. The dicarboxylic acid is an aromatic dicarboxylic acid; the aromatic dicarboxylic acid is terephthalic acid. The diamine is an aliphatic diamine; the aliphatic diamine is hexamethylenediamine.

2. The method for preparing the high-temperature resistant nylon block copolymer according to claim 1, characterized in that: The molar ratio of the dicarboxylic acid to the diamine is (0.98-1.05):

1.

3. The method for preparing the high-temperature resistant nylon block copolymer according to claim 1, characterized in that: The salt-making reaction is carried out at a temperature of 105-160℃ for 1-3 hours.

4. The method for preparing the high-temperature resistant nylon block copolymer according to claim 1, characterized in that: The relative viscosity of the PA56 or PA66 / PA6 copolymer resin is 2.0-2.

7.

5. The method for preparing the high-temperature resistant nylon block copolymer according to claim 1, characterized in that: The antioxidant is at least one of β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, N,N-bis-(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl)hexamethylenediamine, and tris[2,4-di-tert-butylphenyl]phosphite.

6. The method for preparing the high-temperature resistant nylon block copolymer according to claim 1, characterized in that: The capping agent is at least one of benzoic acid, acetic acid, propionic acid, and phthalic anhydride.

7. The method for preparing the high-temperature resistant nylon block copolymer according to claim 1, characterized in that: The catalyst is at least one of sodium phosphate, magnesium phosphate, calcium phosphate, sodium phosphite, magnesium phosphite, calcium phosphite, zinc phosphite, sodium hypophosphite, magnesium hypophosphite, calcium hypophosphite, and zinc hypophosphite.

8. A high temperature resistant nylon block copolymer characterized by: The high-temperature resistant nylon block copolymer is prepared by the preparation method according to any one of claims 1 to 7.

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