阅读说明：本技术 一种三元共聚耐高温尼龙及其制备方法 (Terpolymer high-temperature-resistant nylon and preparation method thereof ) 是由 徐惠祥 王文志 于 2019-03-15 设计创作，主要内容包括：本发明公开了一种三元共聚耐高温尼龙及其制备方法,该三元共聚耐高温尼龙具有如式(I)所示的结构部分,式(I)中,a为6～13,优选为6、9、10、11、12或13,b为4～11,优选为4、8、10或11,c为6～10,优选为6、9或10,d为4～10,优选为4、8或10,R<Sub>1</Sub>选自如式(1)-(7)中所示结构的一种或几种。该耐高温尼龙由以下方法制得：将具有R<Sub>1</Sub>结构的二元酸与脂肪族二元胺反应,得到A；对苯二甲胺与脂肪族二元酸反应,得到B；A、B和脂肪族尼龙盐反应,制得三元共聚耐高温尼龙。本发明的三元共聚耐高温尼龙具有优异的力学性能、耐热性能、阻燃性能和抗熔滴性能,低吸水率,应用于电子电器、LED领域、汽车领域、航空航天和军工领域。(The invention discloses a terpolymer high-temperature-resistant nylon and a preparation method thereof, wherein the terpolymer high-temperature-resistant nylon has a structural part shown in a formula (I), in the formula (I), a is 6-13, preferably 6, 9, 10, 11, 12 or 13, b is 4-11, preferably 4, 8, 10 or 11, c is 6-10, preferably 6, 9 or 10, d is 4-10, preferably 4, 8 or 10, R is 1 Is selected from one or more of the structures shown in formulas (1) to (7). The high-temperature resistant nylon is prepared by the following method: will have R 1 Reacting dibasic acid with aliphatic diamine to obtain A; p-xylylenediamine reacts with aliphatic dibasic acid to obtain B; A. b, reacting with aliphatic nylon salt to obtain the ternary polymerization high temperature resistant nylon. The ternary polymerization high-temperature-resistant nylon has excellent mechanical property, heat resistance, flame retardance, anti-dripping property and low water absorption rate, and is applied to the fields of electronic and electric appliances, LEDs, automobiles, aerospace and war industry.)

1. The terpolymer high-temperature-resistant nylon is characterized by comprising a structural part shown in a formula (I):

in the formula (I), a is 6-13, preferably 6, 9, 10, 11, 12 or 13, b is 4-11, preferably 4, 8, 10 or 11, c is 6-10, preferably 6, 9 or 10, d is 4-10, preferably 4, 8 or 10,

R₁one or more selected from the group consisting of structures shown in formulas (1) to (7):

2. the terpolymer high temperature nylon of claim 1, wherein a is 6, 10 or 12, b is 4 or 8, c is 6 or 10, and d is 4 or 8.

3. The high temperature resistant terpolymer nylon of claim 1 or 2,

4. The high temperature terpolymer nylon according to one of claims 1 to 3, characterized in that in formula (I),

the catalyst is prepared from aliphatic dibasic acid and p-xylylenediamine, wherein the molar ratio of the aliphatic dibasic acid to the p-xylylenediamine is (0.95-1): 1, preferably (0.97 to 1): 1,

from aliphatic dibasic acids and fatsThe aliphatic diamine is prepared from aliphatic dibasic acid and aliphatic diamine in a molar ratio of (0.95-1): 1, preferably (0.97 to 1): 1.

5. the terpolymer high-temperature-resistant nylon is characterized by being prepared by the following method:

step 1, having R₁Reacting dibasic acid with aliphatic diamine to obtain A;

step 2, reacting p-xylylenediamine with aliphatic dibasic acid to obtain B;

and 3, reacting A, B with aliphatic nylon salt to obtain the ternary polymerization high temperature resistant nylon.

6. The high temperature nylon of claim 5, wherein R is the same as R in step 1₁One or more selected from the group consisting of the structures represented in the formulae (1) to (8) as set forth in claim 1.

7. The high temperature resistant terpolymer nylon of claim 5 or 6,

said has R₁The dibasic acid with the structure is salified with aliphatic diamine in water and has R₁The molar ratio of the novel dibasic acid with the structure to the aliphatic diamine is (0.95-1): 1, preferably (0.97 to 1): 1;

salifying an aliphatic dibasic acid and p-xylylenediamine in water, wherein the molar ratio of the aliphatic dibasic acid to the p-xylylenediamine is (0.95-1): 1, preferably (0.97 to 1): 1.

8. the terpolymer high temperature resistant nylon according to one of claims 4 to 7, wherein in step 1, A has a structure represented by the following formula (II);

in formula (II), a is 6, 9, 10, 11, 12 or 13; and/or

B has a structure represented by the following formula (III):

in the formula (III), b is 4, 8, 10 or 11,

the aliphatic nylon salt has a structure represented by the following formula (IV):

in the formula (IV), c is 6, 9 or 10, d is 4, 8 or 10,

in the step 3, a catalyst and an initiator are added in the reaction, wherein the catalyst is selected from one or more of phosphoric acid, hypophosphorous acid, phosphite, hydrogen phosphate, hypophosphite and hypophosphite, and the initiator is water.

9. The terpolymer high temperature resistant nylon according to one of claims 4 to 8, wherein step 3 comprises:

adding A, B and aliphatic nylon salt into a reaction kettle, adding a catalyst and an initiator simultaneously, replacing air in the reaction kettle with inert gas for 3-10 times, heating to 160-220 ℃, and keeping the pressure in the kettle at 1.0-3.0 MPa;

and (2) continuously heating to 230-380 ℃, keeping the pressure in the kettle at 1.0-2.8 MPa, maintaining the pressure for 0.5-5 h, then discharging the gas to normal pressure, discharging the water in the system, gradually vacuumizing to reduce the pressure of the system to-0.03-0.07 MPa, and discharging to obtain the ternary polymerization high temperature resistant nylon.

10. A method for preparing terpolymer high-temperature-resistant nylon, preferably a method for preparing the terpolymer high-temperature-resistant nylon of any one of claims 1 to 9.

Technical Field

The invention relates to the field of high polymer materials, in particular to terpolymer high-temperature-resistant nylon and a preparation method thereof.

Background

Polyamide (PA), commonly known as nylon, is a generic name for resins containing recurring amide groups in the molecular chain. The nylon is the basic resin with the maximum yield, the maximum variety, the widest application and the excellent comprehensive performance in five general engineering plastics. The high-temperature resistant nylon is nylon engineering plastic which can be used at the temperature of more than 150 ℃ for a long time. The high-temperature resistant nylon has good wear resistance, heat resistance, oil resistance and chemical resistance, greatly reduces the water absorption rate and shrinkage rate of raw materials, and has excellent dimensional stability and excellent mechanical strength. The varieties which are industrialized at present are PA46, PA6T, PA9T and the like. The Dutch DSM company in 1990 realizes the industrialization of the high temperature resistant nylon PA46 for the first time, and pulls open the curtain of the high temperature nylon research.

High temperature resistant polyamides are typically prepared by the polycondensation of aliphatic diamines or diacids with aromatic ring containing diamines or diacids. Chinese patent 201510582636 discloses a high temperature resistant branched polyamide block copolymer and a method for preparing the same, wherein the high temperature resistant branched polyamide block copolymer is composed of 20-50 mol% of lactam, 25-40 mol% of aromatic dibasic acid and/or alicyclic dibasic acid, 25-40 mol% of aromatic diamine and/or aliphatic diamine, and 0.2-0.5 mol% of a compound containing three or more functional groups capable of reacting with acid or amine. Chinese patent 201510890733 discloses a high temperature resistant polyamide and a synthesis method thereof, wherein the high temperature resistant polyamide is obtained by copolymerizing semi-aromatic polyamide and polyesteramide. Chinese patent 201110279156 discloses a high temperature resistant semi-aromatic polyamide, a preparation method and an application thereof, which mainly comprises 20-60 wt% of nylon salt formed by isophthalic acid and aliphatic diamine, 30-70 wt% of nylon salt formed by terephthalic acid and aliphatic diamine and 1-15 wt% of polyfunctional group active monomer substance. However, the existing preparation method of the high-temperature resistant nylon has a series of problems of few monomer types, complex synthetic route, low monomer activity, little development of the functionalized high-temperature resistant nylon and the like.

Disclosure of Invention

In order to overcome the problems, the inventors of the present invention have made intensive studies to develop a terpolymer high temperature resistant nylon, which is a triblock copolymer, the main molecular chain of which comprises imide rings and benzene rings with a high density, so that the terpolymer has a high glass transition temperature, a high char yield, excellent flame retardant properties and heat resistance, and the main molecular chain of which further comprises an aliphatic chain, so as to adjust the melting point of the terpolymer and reduce the production cost of the high temperature resistant nylon.

The invention aims to provide a terpolymer high-temperature-resistant nylon which has a structural part shown as a formula (I):

in the formula (I), a is 6-13, preferably 6, 9, 10, 11, 12 or 13, b is 4-11, preferably 4, 8, 10 or 11, c is 6-10, preferably 6, 9 or 10, d is 4-10, preferably 4, 8 or 10,

wherein R is₁One or more selected from the group consisting of structures shown in formulas (1) to (7):

the invention also provides ternary polymerization high-temperature-resistant nylon which is prepared by the following method:

step 1, reacting novel dibasic acid with an R1 structure with aliphatic diamine to obtain A;

step 2, reacting p-xylylenediamine with aliphatic dibasic acid to obtain B;

and 3, reacting A, B with aliphatic nylon salt to obtain the ternary polymerization high temperature resistant nylon.

The third aspect of the invention provides a method for preparing terpolymer high-temperature-resistant nylon, preferably a method for preparing the high-temperature-resistant nylon of the first aspect and the second aspect of the invention.

The invention has the following beneficial effects:

(1) the macromolecular main chain of the terpolymer high-temperature-resistant nylon comprises a rigid structure, such as a rigid structure benzene ring with higher density, and also comprises an imide ring, so that the heat resistance, the mechanical property and the flame retardant property of the high-temperature-resistant nylon are improved, for example, the tensile strength of the terpolymer high-temperature-resistant nylon can reach 123.6 MPa; the bending strength can reach 180.9 MPa; the limit oxygen index can reach 30%; the glass transition temperature can reach 184.2 ℃;

(2) the macromolecular main chain of the ternary polymerization high-temperature-resistant nylon comprises a flexible chain part, such as a copolymerization structure obtained by aliphatic nylon salt, so that the melting point of the high-temperature-resistant nylon can be adjusted, and the production cost can be reduced by adopting the aliphatic nylon salt copolymerization component, thereby being beneficial to the industrial production of the high-temperature-resistant nylon.

(3) The ternary polymerization high-temperature-resistant nylon is prepared from a plurality of different monomers, including binary acid containing benzene rings and imide rings, aliphatic binary acid, aliphatic diamine and p-xylylenediamine, and the ternary polymerization high-temperature-resistant nylon is endowed with multiple functions.

(4) The ternary polymerization high temperature resistant nylon of the invention has the advantages of multiple monomer types, high monomer activity, simple synthetic route and capability of obtaining multifunctional high temperature resistant nylon.

Drawings

FIG. 1 shows an infrared spectrum of a terpolymer thermostable nylon obtained in example 1.

Detailed Description

The invention is explained in more detail below with reference to the drawings and preferred embodiments. The features and advantages of the present invention will become more apparent from the description.

The invention provides a ternary polymerization high-temperature resistant nylon, which has a structural part shown in a formula (I):

in the invention, the terpolymer high-temperature-resistant nylon has a structural part shown as a formula (I), wherein values of a, b, c and d have important influence on the heat resistance, the thermal stability and the mechanical property of the terpolymer high-temperature-resistant nylon.

According to the invention, in the formula (I), a is 6-13, preferably 6, 9, 10, 11, 12 or 13, more preferably 6 or 10, and more preferably 6; b is 4-11, preferably 4, 8, 10 or 11, more preferably 4 or 8, and more preferably 4; c is 6-10, preferably 6, 9 or 10, more preferably 6 or 10, and more preferably 6; d is 4-10, preferably 4, 8 or 10, more preferably 4 or 10, and more preferably 4.

According to the invention, R₁One or more selected from the group consisting of structures shown in formulas (1) to (7):

in the present invention, R₁The structure contains at least two benzene rings, and the benzene rings are rigid structures, so that the high-temperature-resistant nylon can be endowed with excellent heat resistance and mechanical properties, such as higher glass transition temperature; in addition, R₁The structure contains imide rings, the imide rings can endow the high-temperature-resistant nylon with excellent flame retardant property and heat resistance, and the imide rings are easy to form carbon and have higher carbon forming rate, so that the high-temperature-resistant nylon can be endowed with anti-dripping performance.

In the invention, the formula (I) comprises a copolymerization component A, a copolymerization component B and a copolymerization component C, wherein the copolymerization component A is

The copolymerization component B isThe copolymerization component C is

According to the invention, in the formula (I), the weight of the copolymerization component A accounts for 10-30%, preferably 15-30%, and more preferably 20-30% of the weight of the terpolymer high temperature resistant nylon.

In the present invention, R is present in the copolymerization component A₁Structure R₁The nylon has a benzene ring and an imide ring with higher density, and endows the terpolymer high-temperature-resistant nylon with excellent heat resistance, flame retardant property and higher char yield.

According to the invention, in the formula (I), the copolymerization component A consists of a polymer having R₁Prepared from structural dibasic acids and aliphatic diamines, preferably with R₁The dibasic acid with the structure is prepared by salifying the dibasic acid with aliphatic diamine in water, wherein R is contained₁The molar ratio of the dibasic acid with the structure to the aliphatic diamine is (0.95-1): 1, preferably (0.97 to 1): 1, e.g. 0.98: 1.

According to the invention, in the copolymerization component A, a is 6, 9, 10, 11, 12 or 13, preferably 6 or 10.

According to a preferred embodiment of the invention, a in the copolymerization component A is 6, i.e.the copolymerization component A is composed of hexamethylenediamine and has R₁The dibasic acid with the structure is polymerized.

According to the invention, when R₁When the structure is represented by the formula (1), has R₁The diacid with the structure is 2, 4-diphenyl symmetrical triazine-N-carboxyl phenyl phthalimide; when R is₁When it is a structure represented by the formula (2), it has R₁The diacid with the structure is 3,3 ', 4, 4' -m-terphenyl-N-carboxyphenylphthalimide; when R is₁When it is a structure represented by the formula (3), it has R₁The diacid with the structure is 3,3 ', 4, 4' -p-terphenyl-N-carboxyphenylphthalimide; when R is₁When it is a structure represented by the formula (4), it has R₁The diacid with the structure is 2,3,6, 7-anthracene-N-carboxyphenylphthalimide; when R is₁When it is a structure represented by the formula (5), it has R₁The diacid with the structure is 3,3 ', 4, 4' -para-biphenyl-N-carboxyphenylphthalimide; when R is₁When it is a structure represented by the formula (6), it has R₁The diacid with the structure is 3,3 ', 4, 4' -para-terphenyl-N-carboxyphenylphthalimide; when R is₁When it is a structure represented by the formula (7), it has R₁The diacid with the structure is 3,3 ', 4, 4' -para-quaterphenyl-N-carboxyphenylphthalimide.

In the invention, the copolymerization component B accounts for the largest proportion in the ternary polymerization high-temperature resistant nylon, so that the ternary polymerization high-temperature resistant nylon has higher benzene ring density in a macromolecular main chain of the ternary polymerization high-temperature resistant nylon, and a benzene ring is in a rigid structure, thereby endowing the ternary polymerization high-temperature resistant nylon with excellent heat resistance.

According to the invention, in the formula (I), the weight of the copolymerization component B accounts for 30-60%, preferably 40-60%, and more preferably 50-60% of the weight of the terpolymer high temperature resistant nylon.

According to the invention, the copolymerization component B is prepared by polymerizing p-xylylenediamine and aliphatic dibasic acid, wherein the molar ratio of p-xylylenediamine to aliphatic dibasic acid is (0.95-1): 1, preferably (0.97 to 1): 1, for example 0.98:1 or 1: 1.

According to the invention, in the copolymerization component B, B is 4, 8, 10 or 11, preferably 4 or 8.

According to a preferred embodiment of the invention, B is 4 in the copolymerization component B, i.e. the copolymerization component B is prepared from adipic acid and p-xylylenediamine, preferably from adipic acid and p-xylylenediamine salified in water.

According to the invention, the sum of the proportions by weight of copolymerization component A, copolymerization component B and copolymerization component C in formula (I) is 100%.

According to the invention, the copolymerization component C is aliphatic nylon salt prepared from aliphatic dibasic acid and aliphatic diamine, preferably aliphatic nylon salt prepared from aliphatic dibasic acid and aliphatic diamine through salt formation in water, wherein the molar ratio of the aliphatic dibasic acid to the aliphatic diamine is (0.95-1): 1, preferably (0.97 to 1): 1, for example 0.98:1 or 1: 1.

According to a preferred embodiment of the present invention, in the copolymerization component C, C is 6 and d is 4, i.e. the copolymerization component C is prepared from adipic acid and hexamethylenediamine, preferably from adipic acid and hexamethylenediamine by salification in water.

The invention also provides ternary polymerization high-temperature resistant nylon which is prepared by the following method:

step 1, having R₁Reacting the dibasic acid with aliphatic diamine to obtain a copolymerization component A;

according to the invention, having R₁The dibasic acid of structure may be represented as HOOC-R₁-COOH, wherein R₁Selected from the group described in the first aspect of the present inventionOne or more of the structures shown in formulas (1) - (8).

According to the invention, in step 1, the resulting copolymer component A has a structural moiety represented by the following formula (II):

according to the invention, in formula (II), a is 6, 9, 10, 11, 12 or 13, preferably 6 or 10, more preferably 6. That is, in step 1, the aliphatic diamine is hexamethylenediamine, nonanediamine, decanediamine, undecanediamine, dodecanediamine, or tridecanediamine.

According to the invention, in step 1, R is present₁Reacting the dibasic acid with the structure and aliphatic diamine in water to form salt to obtain the compound A.

In the present invention, R is₁The dibasic acid monomers with the structure are various, the carboxyl is directly connected to the benzene ring, the monomer activity is high, the reaction activity is high when the melt polycondensation is carried out, and the copolymerization high-temperature-resistant nylon resin with high relative viscosity (for example, the relative viscosity is 2.2-2.8, preferably 2.2-2.5, and more preferably 2.2-2.3) can be obtained.

The inventors have found that₁The reaction system for the salt formation of the dibasic acid and the aliphatic diamine needs to be in an alkaline environment, the pH value of the reaction system is preferably 7.5-8.5, the diamine can be lost in the polymerization heating process, the use amount of the diamine can be properly increased to ensure that the molar ratio of the dibasic acid to the diamine is 1:1 to carry out polymerization reaction, the molar amount of the diamine is slightly higher than that of the dibasic acid, the reaction system is in an alkaline environment, the dibasic acid and the diamine are polymerized in a ratio of 1:1, and the copolymerization component A with higher molecular weight is obtained.

According to the invention, in step 1, R is present₁The molar ratio of the dibasic acid with the structure to the aliphatic diamine is (0.95-1): 1, preferably (0.97 to 1): 1, for example 0.98:1 or 1: 1.

In the present invention, A is represented by R₁The copolymer obtained by the reaction of dibasic acid with aliphatic diamine has a molecular main chain containing R₁Structure R₁Benzene ring and acyl in the structureThe ternary polymerization high-temperature resistant nylon obtained by taking the imine ring endowing agent A as a copolymerization component has excellent mechanical property (such as tensile strength reaching 123.6MPa), heat resistance (such as glass transition temperature reaching 184.2 ℃), excellent flame retardant property (such as limited oxygen index reaching 30%) and anti-dripping property (such as higher char yield).

Step 2, reacting p-xylylenediamine with aliphatic dibasic acid to obtain B;

according to the invention, in step 2, B has a structure as shown in formula (III):

in formula (III), b is 4, 8, 10 or 11, preferably 4 or 8, more preferably 4. Namely, in step 2, the aliphatic dibasic acid is adipic acid, sebacic acid, dodecanedioic acid or tridecanedioic acid.

According to a preferred embodiment of the invention, step 2, adipic acid is salified with p-xylylenediamine in water to give B.

The inventor finds that salifying of aliphatic dibasic acid and p-xylylenediamine requires that a reaction system is in an alkaline environment, the pH of the reaction system is preferably 7.5-8.5, diamine is lost in the polymerization temperature rise process, the use amount of diamine can be properly increased to ensure that the molar weight of the diamine is slightly higher than that of the dibasic acid in order to ensure that the dibasic acid and the diamine are subjected to polymerization reaction in a molar ratio of 1:1, so that the reaction system is in the alkaline environment, and the dibasic acid and the diamine are polymerized into salt in a ratio of 1:1 to obtain the copolymerization component B with higher molecular weight.

According to the invention, in the step 2, the molar ratio of adipic acid to p-xylylenediamine is (0.95-1): 1, preferably (0.97 to 1): 1, for example 0.98:1 or 1: 1.

According to the invention, the copolymerization component B contains benzene rings, and when the terpolymer high-temperature-resistant nylon is prepared, the high-temperature-resistant nylon macromolecule main chain has higher benzene ring density and the molecular chain is endowed with certain rigidity by virtue of the rigid structure of the benzene rings, so that the high-temperature-resistant nylon has excellent heat resistance and mechanical properties, especially higher glass transition temperature.

And 3, reacting A, B with aliphatic nylon salt to obtain the ternary polymerization high temperature resistant nylon.

According to the invention, in the step 3, A, B and aliphatic nylon salt are subjected to melt polycondensation in a reaction kettle to obtain the ternary polymerization high temperature resistant nylon.

According to the invention, different proportions of A, B and aliphatic nylon salt have important influence on the comprehensive performance of the high-temperature resistant nylon, and the component A ensures that the terpolymer high-temperature resistant nylon has excellent mechanical property, heat resistance, flame retardance, anti-dripping property and the like; the component B is used as a main component of the terpolymer to ensure that a macromolecular main chain of the terpolymer has higher benzene ring density, so that the obtained terpolymer has excellent heat resistance; the component C mainly plays a role in adjusting the melting point of the terpolymer and reducing the cost. The change of the addition amount of the three components leads to the change of the rigidity and flexibility of the molecular main chain of the copolymer, thereby leading to the change of the mechanical property, the crystallization property, the flame retardance, the melting point and other properties of the copolymer.

According to the invention, in step 3, a catalyst and an initiator are added to the reaction to catalyze and initiate the reaction.

According to the invention, the catalyst is selected from one or more of phosphoric acid, hypophosphorous acid, phosphites, hydrogen phosphates, hypophosphites and hypophosphites.

According to the invention, the phosphite is selected from one or more of potassium phosphite, sodium phosphite, magnesium phosphite, calcium phosphite, aluminum phosphite, zinc phosphite.

According to the invention, the hydrogen phosphate is selected from one or more of magnesium hydrogen phosphate, potassium hydrogen phosphate and sodium hydrogen phosphate.

According to the invention, the hypophosphite is selected from one or more of sodium hypophosphite, calcium hypophosphite and magnesium hypophosphite.

According to the invention, the hypophosphite is selected from one or more of sodium hypophosphite, magnesium hypophosphite, calcium hypophosphite and zinc hypophosphite.

According to a preferred embodiment of the invention, the catalyst is one or more of phosphoric acid, phosphorous acid and sodium hypophosphite, such as sodium hypophosphite.

According to the invention, in the step 3, the addition amount of the catalyst is 0.1-2%, preferably 0.1-1%, and more preferably 0.1-0.5% of the total weight of the copolymerization component A, the copolymerization component B and the aliphatic nylon salt.

According to the invention, the initiator is water, preferably deionized or distilled water.

According to the invention, in the step 3, the addition amount of the initiator is 1-10%, preferably 1.5-8%, and more preferably 2-5% of the total weight of the copolymerization component A, the copolymerization component B and the aliphatic nylon salt.

According to the invention, step 3 comprises:

adding A, B and aliphatic nylon salt into a reaction kettle, adding a catalyst and an initiator simultaneously, replacing air in the reaction kettle with inert gas for 3-10 times, heating to 160-220 ℃, and keeping the pressure in the kettle at 1.0-3.0 MPa.

In the invention, the step (1) is a prepolymerization process, the water in the reaction kettle is preliminarily discharged, and the salt solution is further concentrated.

According to the invention, in the step (1), A, B and aliphatic nylon salt are added into a reaction kettle, and simultaneously a catalyst and an initiator are added, so that the reaction kettle needs to be filled with inert gas because the melt polycondensation reaction needs to be carried out in an inert environment.

According to the present invention, in step (1), the air in the reaction vessel is replaced with an inert gas 3 to 10 times, preferably 3 to 7 times, and more preferably 3 to 4 times, thereby ensuring an inert atmosphere in the reaction vessel.

According to the invention, the inert gas is preferably nitrogen or argon.

According to the invention, the temperature of the reaction kettle is increased to 180-210 ℃, and the pressure in the reaction kettle is kept at 1.2-2.8 MPa; preferably, the temperature of the reaction kettle is raised to 190-200 ℃, and the pressure in the reaction kettle is kept at 1.5-2.5 MPa.

And (2) continuously heating to 230-380 ℃, keeping the pressure in the kettle at 1.0-2.8 MPa, maintaining the pressure for 0.5-5 h, then discharging the gas to normal pressure, discharging the water in the system, gradually vacuumizing to reduce the pressure of the system to-0.03-0.07 MPa, and discharging to obtain the ternary polymerization high temperature resistant nylon.

In the invention, the reduced pressure polycondensation in the step (2) enables the polymerization reaction to proceed forward and backward, and the molecular weight is increased, so that the copolymerized high temperature resistant nylon obtained by polymerization has better relative viscosity (for example, the relative viscosity is 2.2-2.8).

Preferably, in the step (2), the temperature of the reaction kettle is continuously increased to 250-350 ℃, the pressure in the reaction kettle is kept at 1.2-2.5 MPa, the pressure is kept for 1-4 h,

more preferably, the temperature of the reaction kettle is continuously increased to 290-320 ℃, the pressure in the kettle is kept at 1.5-2.0 MPa, and the pressure keeping time is 1-2 h.

According to the invention, the copolymerization component A, the copolymerization component B and the aliphatic nylon salt are subjected to melt polycondensation to prepare the ternary polymerization high-temperature-resistant nylon, the high-temperature-resistant nylon molecular chain comprises a triblock structure of the copolymerization component A, the copolymerization component B and the aliphatic nylon salt, the three block units enable the high-temperature-resistant nylon to be multifunctional, and the structure and the performance of the high-temperature-resistant nylon can be adjusted by adjusting the structure and the content of the three block units.

According to the invention, the ternary polymerization high temperature resistant nylon has excellent mechanical property, heat resistance, flame retardant property and low water absorption, for example, the tensile strength is higher than 92.9MPa, and even can reach 123.6 MPa; the bending strength is higher than 154.8MPa and can reach 180.9 MPa; the notch impact strength is higher than 4MPa and can reach 6.5 MPa; the limiting oxygen index is more than or equal to 28 percent and can even reach 30 percent; the glass transition temperature is higher than 166.9 ℃, and can even reach 184.2 ℃; the water absorption is less than or equal to 1.6 percent, even as low as 0.9 percent.