Polyamide composition material for automotive air conditioning pipes and preparation method and application thereof

Abstract

This invention relates to a polyamide composition material for automotive air conditioning pipes, its preparation method, and its application. The polyamide composition material for automotive air conditioning pipes is prepared from the following components in parts by weight: 80-93.7 parts polyamide resin, 0.1-2 parts chain extender, 0-6 parts plasticizer, 3-15 parts toughening agent, 0.1-3 parts antioxidant, 0.1-2 parts lubricant, 0-3 parts light stabilizer, and 0-3 parts color masterbatch. The polyamide composition material for automotive air conditioning pipes of this invention is used to prepare all-plastic polyamide air conditioning pipes. Compared with commonly used rubber / aluminum pipe combination air conditioning pipes, it reduces weight by 50%, lowers cost by 25%, reduces the number of crimped connections, reduces leakage, eliminates the need for processing aids during pipe manufacturing, and significantly reduces refrigerant permeability, allowing for refrigerant pipe usage requirements even with thinner pipe wall thicknesses.

Description

Technical Field

[0001] This invention relates to the field of polymer materials technology, and in particular to a polyamide composition material for automotive air conditioning pipes, its preparation method, and its application. Background Technology

[0002] With the rapid development of the new energy vehicle industry, the requirements for automotive thermal management systems are increasing. Among them, air conditioning cooling pipes are an important part of the thermal management system. Currently, commonly used automotive air conditioning refrigerant pipes are mostly aluminum pipes with multi-layer braided rubber / PA6 tubing. However, this type of pipe is complex to process, heavy, and prone to refrigerant leakage.

[0003] Currently, both OEMs and material manufacturers are actively developing all-plastic air conditioning pipe solutions. Because long-chain nylon has better refrigerant permeability resistance than rubber and PA6, some long-chain nylon all-plastic pipe solutions have been disclosed. For example, patent CN113502050A discloses an automotive air conditioning pipe material and its preparation method. This automotive air conditioning pipe material uses PA1012 resin, with added compatibilizers, polypropylene resin, and other additives. The resulting automotive air conditioning pipe is lightweight and has a small inner surface roughness, which can effectively improve refrigerant flow efficiency. However, PA1012 resin itself has poor refrigerant permeability resistance, which can easily cause rapid refrigerant loss. Summary of the Invention

[0004] Based on this, the purpose of this invention is to provide a polyamide material for automotive air conditioning pipes, its preparation method, and its application. This polyamide composition material for automotive air conditioning pipes is used to prepare all-plastic polyamide air conditioning pipes. Compared with the commonly used rubber / aluminum pipe combination air conditioning pipes, it reduces weight by 50%, costs by 25%, reduces the number of crimped connections, reduces leakage, does not require processing aids during pipe manufacturing, and can greatly reduce refrigerant permeability. It can meet the refrigerant pipe usage requirements under thinner pipe wall thickness conditions.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] The present invention provides a polyamide composition material for automotive air conditioning pipes, which is prepared from the following components in parts by weight: 80-93.7 parts of polyamide resin, 0.1-2 parts of chain extender, 0-6 parts of plasticizer, 3-15 parts of toughening agent, 0.1-3 parts of antioxidant, 0.1-2 parts of lubricant, 0-3 parts of light stabilizer, and 0-3 parts of color masterbatch.

[0007] As a further improvement to the above-described scheme of the present invention, the polyamide resin is a copolymer polyamide resin, and the relative viscosity of the copolymer polyamide resin is 2.2-3.6.

[0008] As a further improvement to the above-described scheme of the present invention, the copolyamide resin is at least one of PA610 / MXD6, PA612 / MXD6, PA614 / MXD6, PA1010 / MXD6, PA1012 / MXD6, and PA1014 / MXD6.

[0009] As a further improvement to the above-mentioned scheme of the present invention, the preparation method of the copolymer polyamide resin is as follows: a polyamide salt solution and an MXD6 salt solution are added to a polymerization reactor, heated to 230-260°C, and then the reaction is carried out under normal pressure with nitrogen purging for 2-5 hours. Then, the reaction is carried out under vacuum for 1-2 hours at a pressure lower than 400Pa to obtain the polymerization product. The copolymer polyamide resin is obtained by stretching, pelletizing, and drying. The polyamide salt solution is at least one of PA610 salt solution, PA612 salt solution, PA614 salt solution, PA1010 salt solution, PA1012 salt solution, and PA1014 salt solution.

[0010] As a further improvement to the above-mentioned scheme of the present invention, the weight ratio of polyamide salt in the polyamide salt solution to MXD6 salt in the MXD6 salt solution is 4-30:1.

[0011] As a further improvement to the above-mentioned scheme of the present invention, the concentration of the polyamide salt solution and the MXD6 salt solution is 30-70%.

[0012] As a further improvement to the above-mentioned solution of the present invention, the PA610 salt solution is prepared by weighing hexamethylenediamine and sebacic acid in an equimolar ratio, adding them to deionized water, and then heating and stirring.

[0013] And / or, the PA612 salt solution is prepared by adding ethylenediamine and dodecanoic acid to deionized water and then heating and stirring.

[0014] And / or, the PA614 salt solution is prepared by weighing ethylenediamine and tetradecanoic acid in an equimolar ratio, adding them to deionized water, and then heating and stirring.

[0015] And / or, the PA1010 salt solution is prepared by weighing decanediamine and sebacic acid in an equimolar ratio, adding them to deionized water, and then heating and stirring.

[0016] The PA1012 salt solution is prepared by weighing decanediamine and dodecanoic acid in an equimolar ratio, adding them to deionized water, and then heating and stirring.

[0017] The PA1014 salt solution is prepared by weighing decanediamine and tetradecanoic acid in an equimolar ratio, adding them to deionized water, and then heating and stirring.

[0018] As a further improvement to the above-mentioned solution of the present invention, the chain extender is a copolymer of ethylene and maleic anhydride, preferably ZeMac E60P;

[0019] And / or, the plasticizer is N-butylbenzenesulfonamide;

[0020] And / or, the toughening agent is at least one of maleic anhydride-grafted POE, maleic anhydride-grafted SEBS, and maleic anhydride-grafted EPDM;

[0021] And / or, the antioxidant is one or two of BASF Irganox 245, BASF Irganox 1098, and BASF Irganox 168;

[0022] And / or, the lubricant is one or both of calcium stearate and pentaerythritol stearate;

[0023] And / or, the light stabilizer is one or both of BASF Tinuvin 234 and BASF Tinuvin 770;

[0024] And / or, the color masterbatch is at least one of PA color masterbatch, PP color masterbatch, and PE color masterbatch.

[0025] The present invention also provides a method for preparing the polyamide composition material for automotive air conditioning pipes as described above. The method involves mixing polyamide resin, chain extender, toughening agent, antioxidant, lubricant, light stabilizer, and color masterbatch in proportion to obtain material one; feeding material one into zone one of an extruder through a loss-in-weight weigher; feeding plasticizer into zone six of the extruder in proportion through a liquid metering weigher; melting, extruding, granulating, and drying to obtain the polyamide composition material for automotive air conditioning pipes.

[0026] As a further improvement to the above-mentioned solution of the present invention, the extruder is a twin-screw extruder with a ten-section barrel. The temperatures of each zone of the twin-screw extruder are as follows: Zone 1: 120-200℃; Zone 2: 230-290℃; Zone 3: 230-290℃; Zone 4: 230-290℃; Zone 5: 230-290℃; Zone 6: 230-290℃; Zone 7: 230-290℃; Zone 8: 230-290℃; Zone 9: 230-290℃; Zone 10: 230-290℃; Die head temperature: 230-290℃; The main rotation speed of the twin-screw extruder is 200-1000 r / min.

[0027] The present invention also provides the application of the polyamide composition material for automotive air conditioning pipes as described above in the preparation of automotive air conditioning pipes.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] 1. The polyamide composition material for automotive air conditioning pipes provided by the present invention can be used to prepare all-plastic polyamide air conditioning pipes. Compared with the commonly used rubber / aluminum pipe combination air conditioning pipes, it reduces weight by 50%, costs by 25%, reduces the number of crimped connections, reduces leakage, and does not require processing aids during pipe manufacturing.

[0030] 2. The polyamide composition material for automotive air conditioning pipes provided by the present invention, due to the copolymerization of MXD6 structure in the copolymer polyamide resin, introduces a large number of benzene ring structures into the molecular chain. This structure makes the intermolecular interaction force strong, thereby forming a dense structure that effectively blocks the passage of gas molecules and reduces refrigerant permeation.

[0031] 3. The polyamide composition material for automotive air conditioning pipes provided by the present invention contains a chain extender, which reduces the viscosity requirement of long-chain nylon resin, expands the application range of long-chain nylon, and improves the stability of product extrusion.

[0032] 4. The polyamide composition material for automotive air conditioning pipes provided by the present invention can significantly improve the low-temperature impact performance of the pipe by adding toughening agents such as maleic anhydride-grafted POE, maleic anhydride-grafted SEBS, and maleic anhydride-grafted EPDM; it also has good weather resistance due to the addition of antioxidants and light stabilizers; and it improves the surface brightness of the pipe by adding lubricants. Detailed Implementation

[0033] To facilitate understanding of the present invention, a more comprehensive description will be given below with reference to specific embodiments. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the disclosure of the present invention.

[0034] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0035] The specific information on the raw materials used in the following examples and comparative examples is as follows:

[0036] (1) Self-made copolyamide resin

[0037] Copolymer polyamide resin 1: Hexamethylenediamine and dodecanoic acid were weighed in an equimolar ratio, added to deionized water, and heated and stirred to prepare a 70% concentration PA612 salt solution; m-phenylenediamine and adipic acid were weighed in an equimolar ratio, added to deionized water, and heated and stirred to prepare a 30% concentration MXD6 salt solution; the weight ratio of hexamethylenediamine dodecanoic acid salt to MXD6 salt was controlled at 30:1 based on the weight of the salt in the salt solution; the two salt solutions were added to the polymerization reactor in sequence, heated to 230-260℃, and then purged with nitrogen at normal pressure for 2-5 hours. The reaction was then carried out under vacuum for 1-2 hours at a pressure below 400Pa to obtain the polymerization product. The viscosity was controlled by controlling the stirring current. After pelletizing and drying, a copolymer resin 1 with a relative viscosity of 2.8 was obtained.

[0038] Copolymer polyamide resin 2: Hexamethylenediamine and sebacic acid were weighed in an equimolar ratio, added to deionized water, and heated and stirred to prepare a 50% concentration PA610 salt solution; m-phenylenediamine and adipic acid were weighed in an equimolar ratio, added to deionized water, and heated and stirred to prepare a 50% concentration MXD6 salt solution; the weight ratio of hexamethylenediamine sebacic acid salt to MXD6 salt was controlled at 20:1 based on the weight of salt in the salt solution; the two salt solutions were added to the polymerization reactor in sequence, heated to 230-260℃, and then purged with nitrogen at normal pressure for 2-5 hours. Then, the reaction was carried out under vacuum for 1-2 hours at a pressure below 400Pa to obtain the polymerization product. The viscosity was controlled by controlling the stirring current. After pelletizing and drying, a copolymer resin 2 with a relative viscosity of 2.2 was obtained.

[0039] Copolymer polyamide resin 3: Decanediamine and dodecanoic acid were weighed in an equimolar ratio, added to deionized water, and heated and stirred to prepare a 70% concentration PA1012 salt solution; m-phenylenediamine and adipic acid were weighed in an equimolar ratio, added to deionized water, and heated and stirred to prepare a 50% concentration MXD6 salt solution; the weight ratio of dodecanoic acid decanediamine salt to MXD6 salt was controlled at 10:1 based on the weight of the salt in the salt solution; the two salt solutions were added to the polymerization reactor in sequence, heated to 230-260℃, and then purged with nitrogen at normal pressure for 2-5 hours. Then, the reaction was carried out under vacuum for 1-2 hours at a pressure below 400Pa to obtain the polymerization product. The viscosity was controlled by controlling the stirring current. After pelletizing and drying, a copolymer resin 3 with a relative viscosity of 3.2 was obtained.

[0040] Copolymer polyamide resin 4: Decanediamine and sebacic acid were weighed in an equimolar ratio and added to deionized water. The mixture was heated and stirred to prepare a 30% PA1010 salt solution. m-Phenylenediamine and adipic acid were weighed in an equimolar ratio and added to deionized water. The mixture was heated and stirred to prepare a 70% MXD6 salt solution. The weight ratio of sebacic acid-decanediamine salt to MXD6 salt was controlled at 4:1 based on the weight of the salt in the salt solution. The two salt solutions were added to the polymerization reactor in sequence, heated to 230-260℃, and then purged with nitrogen at normal pressure for 2-5 hours. The reaction was then carried out under vacuum for 1-2 hours at a pressure below 400Pa to obtain the polymerization product. The viscosity was controlled by controlling the stirring current. After pelletizing and drying, a copolymer resin 4 with a relative viscosity of 3.6 was obtained.

[0041] (2) Chain extender: Vantrus ZeMac E60P;

[0042] (3) Plasticizer BBSA, which is Proviplast 024 from Belgium;

[0043] (4) Maleic anhydride grafted POE is Dow Chemical FUSABONDN N216;

[0044] (5) Maleic anhydride grafted SEBS is Kraton polymer FG1901;

[0045] (6) Maleic anhydride-grafted EPDM was ExxonMobil EXXELOR VA1803;

[0046] (7) Calcium stearate is Italian-based calcium stearate;

[0047] (8) Pentaerythritol stearate PETS is Italian-made PETS-AP;

[0048] (9) PA612 is produced by Shandong Dongchen Ruisen New Material Technology Co., Ltd., with a relative viscosity of 2.8;

[0049] (10) Antioxidant 245, antioxidant 1098, PA black masterbatch, light stabilizer BASF Tinuvin 234, and light stabilizer BASF Tinuvin 770 are all commercially available.

[0050] The above-mentioned raw materials are only for illustrating the source and composition of the reagents used in the experiments of this invention, so as to fully disclose them, and do not imply that the invention cannot be achieved by using other similar reagents or reagents provided by other suppliers.

[0051] Unless otherwise specified, the reagents, methods and equipment used in this invention are conventional reagents, methods and equipment in this technical field.

[0052] Example 1

[0053] This embodiment proposes a polyamide composition material for automotive air conditioning pipes, comprising the following components in parts by weight: 86.8 parts of copolyamide resin 1, 0.5 parts of chain extender ZeMac E60P, 2 parts of plasticizer BBSA, 7 parts of maleic anhydride grafted POE, 0.5 parts of antioxidant 245, 0.5 parts of antioxidant 1098, 0.5 parts of antioxidant 168, 0.2 parts of calcium stearate, 1 part of light stabilizer BASF Tinuvin 234, and 1 part of PA black masterbatch.

[0054] The preparation method of the polyamide composition material for automotive air conditioning pipes in this embodiment includes the following steps: adding polyamide resin, chain extender, toughening agent, antioxidant, lubricant, light stabilizer and color masterbatch into a high-speed mixer in proportion, mixing for 2-10 minutes to obtain material one; feeding material one into zone one of a twin-screw extruder through a loss-in-weight weigher, feeding plasticizer into zone six of the twin-screw extruder in proportion through a liquid metering weigher, melting, extruding, granulating, and drying to obtain the polyamide composition material for automotive air conditioning pipes. The twin-screw extruder is a ten-section barrel extruder. The temperatures of each zone of the twin-screw extruder are as follows: Zone 1: 120-200℃, Zone 2: 230-290℃, Zone 3: 230-290℃, Zone 4: 230-290℃, Zone 5: 230-290℃, Zone 6: 230-290℃, Zone 7: 230-290℃, Zone 8: 230-290℃, Zone 9: 230-290℃, Zone 10: 230-290℃; Die head temperature: 230-290℃; The main engine speed of the twin-screw extruder is 200-1000 r / min.

[0055] Example 2

[0056] This embodiment uses the same implementation method as Embodiment 1. The difference from Embodiment 1 is that the polyamide composition material for automotive air conditioning pipes in this embodiment includes the following components in parts by weight: 85.8 parts of copolyamide resin 2, 2 parts of chain extender ZeMac E60P, 6 parts of plasticizer BBSA, 3 parts of maleic anhydride grafted EPDM, 0.1 parts of antioxidant 245, 0.1 parts of PETS, and 3 parts of PA black masterbatch.

[0057] Example 3

[0058] This embodiment uses the same implementation method as Embodiment 1, but differs from Embodiment 1 in that: the polyamide composition material for automotive air conditioning pipes in this embodiment includes the following components in parts by weight: 80 parts of copolyamide resin 3, 0.2 parts of chain extender ZeMac E60P, 15 parts of maleic anhydride grafted SEBS, 1 part of antioxidant 245, 1 part of antioxidant 1098, 1 part of antioxidant 168, 0.1 parts of calcium stearate, and 1.7 parts of PA black masterbatch.

[0059] Example 4

[0060] This embodiment uses the same implementation method as Embodiment 1. The difference from Embodiment 1 is that the polyamide composition material for automotive air conditioning pipes in this embodiment includes the following components in parts by weight: 93.7 parts of copolyamide resin 4, 0.1 parts of chain extender ZeMac E60P, 3 parts of maleic anhydride grafted SEBS, 0.1 parts of antioxidant 245, 0.1 parts of calcium stearate, and 3 parts of light stabilizer BASF Tinuvin 770.

[0061] Example 5

[0062] This embodiment uses the same implementation method as Embodiment 1, except that the polyamide composition material for automotive air conditioning pipes in this embodiment includes the following components in parts by weight: 72.7 parts copolyamide resin 1, 15 parts copolyamide resin 3, 0.3 parts chain extender ZeMac E60P, 4 parts plasticizer BBSA, 3 parts maleic anhydride grafted POE, 2 parts maleic anhydride grafted EPDM, 1 part antioxidant 245, 1 part calcium stearate, and 1 part PETS.

[0063] Comparative Example 1

[0064] This comparative example uses the same implementation method as Example 1, except that the polyamide composition material for automotive air conditioning pipes in this example includes the following components in parts by weight: 86.8 parts PA612, 0.5 parts chain extender ZeMac E60P, 2 parts plasticizer BBSA, 7 parts maleic anhydride grafted POE, 0.5 parts antioxidant 245, 0.5 parts antioxidant 1098, 0.5 parts antioxidant 168, 0.2 parts calcium stearate, 1 part BASF Tinuvin 234, and 1 part PA black masterbatch.

[0065] Comparative Example 2

[0066] This comparative example uses the same implementation method as Example 1, except that the polyamide composition material for automotive air conditioning pipes in this example includes the following components in parts by weight: 86.8 parts copolyamide resin, 1 part plasticizer BBSA, 7 parts maleic anhydride grafted POE, 0.5 parts antioxidant 245, 0.5 parts antioxidant 1098, 0.5 parts antioxidant 168, 0.2 parts calcium stearate, 1 part BASF Tinuvin 234, and 1 part PA black masterbatch.

[0067] Comparative Example 3

[0068] This comparative example uses the same implementation method as Example 1, except that the polyamide composition material for automotive air conditioning pipes in this example includes the following components in parts by weight: 86.8 parts copolyamide resin 1, 0.5 parts chain extender ZeMac E60P, 2 parts plasticizer BBSA, 0.5 parts antioxidant 245, 0.5 parts antioxidant 1098, 0.5 parts antioxidant 168, 0.2 parts calcium stearate, 1 part BASF Tinuvin 234, and 1 part PA black masterbatch.

[0069] The amounts of each raw material in the polyamide composition materials for automotive air conditioning pipes in the above embodiments and comparative examples are shown in Table 1.

[0070] Table 1. Amounts of each raw material in the polyamide composition for automotive air conditioning pipes of the examples and comparative examples.

[0071]

[0072]

[0073] Test case

[0074] The polyamide compositions obtained in Examples 1-5 and Comparative Examples 1-3 were extruded into injection molded strips and pipes, and their mechanical properties were tested; the test results are shown in Table 2. Tensile strength and elongation at break were tested according to ISO 527-1A at a tensile speed of 50 mm / min; -30°C notched impact test was conducted according to ISO 179; melt index test was conducted according to ISO 1133; burst pressure test was conducted according to GB 16897; and permeability test was conducted according to GB / T 20025.

[0075] Table 2 Performance Test Results

[0076]

[0077]

[0078] The results in Table 2 show that:

[0079] Compared with Comparative Example 1, Example 1 used copolyamide resin 1, and the refrigerant permeability of Example 1 was 1.8 kg / (m³). 2 *year) decreased to 0.25kg / (m 2 *year), confirming that the copolymer MXD6 structure can reduce refrigerant permeation performance;

[0080] Compared with Comparative Example 2, Example 1 used a chain extender, and the melt index of Example 1 was reduced from 9.8 to 3.1, thereby enabling stable extrusion of pipes;

[0081] Compared with Comparative Example 3, Example 1 used a toughening agent, and the low-temperature notched impact strength of the simply supported beam in Example 1 was increased from 2.5 KJ / m. 2 Rising to 9.3 KJ / m 2 The pipe can withstand impact at -40℃ without cracking.

[0082] In summary, Embodiments 1, 2, 3, 4, and 5 of this application exhibit good overall performance and can meet the requirements for high-explosiveness and low-permeability air conditioning pipeline applications in new energy vehicles.

[0083] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0084] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A polyamide composition material for automotive air conditioning pipes, characterized in that, It is prepared from the following components in parts by weight: 80-93.7 parts polyamide resin, 0.1-2 parts chain extender, 0-6 parts plasticizer, 3-15 parts toughening agent, 0.1-3 parts antioxidant, 0.1-2 parts lubricant, 0-3 parts light stabilizer, and 0-3 parts color masterbatch; The polyamide resin is a copolymer polyamide resin, and the relative viscosity of the copolymer polyamide resin is 2.2-3.6; the copolymer polyamide resin is at least one of PA610 / MXD6, PA612 / MXD6, PA614 / MXD6, PA1010 / MXD6, PA1012 / MXD6, and PA1014 / MXD6.

2. The polyamide composition material for automotive air conditioning pipes according to claim 1, characterized in that, The preparation method of the copolymer polyamide resin is as follows: a polyamide salt solution and an MXD6 salt solution are added to a polymerization reactor, heated to 230-260°C, and then purged with nitrogen at normal pressure for 2-5 hours. The reaction is then carried out under vacuum for 1-2 hours at a pressure below 400 Pa to obtain the polymerization product. The copolymer polyamide resin is obtained by stretching, pelletizing, and drying. The polyamide salt solution is at least one of PA610 salt solution, PA612 salt solution, PA614 salt solution, PA1010 salt solution, PA1012 salt solution, and PA1014 salt solution.

3. The polyamide composition material for automotive air conditioning pipes according to claim 2, characterized in that, The weight ratio of polyamide salt in the polyamide salt solution to MXD6 salt in the MXD6 salt solution is 4-30:1; And / or, the concentration of the polyamide salt solution or MXD6 salt solution is 30-70%.

4. The polyamide composition material for automotive air conditioning pipes according to claim 2, characterized in that, The PA610 salt solution is prepared by weighing hexamethylenediamine and sebacic acid in an equimolar ratio, adding them to deionized water, and then heating and stirring. And / or, the PA612 salt solution is prepared by weighing ethylenediamine and dodecanoic acid in an equimolar ratio, adding them to deionized water, and then heating and stirring. And / or, the PA614 salt solution is prepared by weighing ethylenediamine and tetradecanoic acid in an equimolar ratio, adding them to deionized water, and then heating and stirring. And / or, the PA1010 salt solution is prepared by weighing decanediamine and sebacic acid in an equimolar ratio, adding them to deionized water, and then heating and stirring. The PA1012 salt solution is prepared by weighing decanediamine and dodecanoic acid in an equimolar ratio, adding them to deionized water, and then heating and stirring. The PA1014 salt solution is prepared by weighing decanediamine and tetradecanoic acid in an equimolar ratio, adding them to deionized water, and then heating and stirring.

5. The polyamide composition material for automotive air conditioning pipes according to claim 1, characterized in that, The chain extender is a copolymer of ethylene and maleic anhydride; And / or, the plasticizer is N-butylbenzenesulfonamide; And / or, the toughening agent is at least one of maleic anhydride-grafted POE, maleic anhydride-grafted SEBS, and maleic anhydride-grafted EPDM; And / or, the antioxidant is one or two of BASF Irganox 245, BASF Irganox 1098, and BASF Irganox 168; And / or, the lubricant is one or both of calcium stearate and pentaerythritol stearate; And / or, the light stabilizer is one or both of BASF Tinuvin 234 and BASF Tinuvin 770; And / or, the color masterbatch is at least one of PA color masterbatch, PP color masterbatch, and PE color masterbatch.

6. A method for preparing a polyamide composition material for automotive air conditioning pipes as described in any one of claims 1-5, characterized in that, After mixing polyamide resin, chain extender, toughening agent, antioxidant, lubricant, light stabilizer and color masterbatch in proportion, material one is obtained. Material one is fed into zone one of the extruder through a loss-in-weight weigher. Plasticizer is fed into zone six of the extruder through a liquid metering weigher in proportion. After melting, extrusion, granulation and drying, the polyamide composition material for automotive air conditioning pipes is obtained.

7. The method for preparing the polyamide composition material for automotive air conditioning pipes according to claim 6, characterized in that, The extruder is a twin-screw extruder with a ten-section barrel. The temperatures of each zone of the twin-screw extruder are as follows: Zone 1: 120-200℃, Zone 2: 230-290℃, Zone 3: 230-290℃, Zone 4: 230-290℃, Zone 5: 230-290℃, Zone 6: 230-290℃, Zone 7: 230-290℃, Zone 8: 230-290℃, Zone 9: 230-290℃, Zone 10: 230-290℃; the die head temperature is 230-290℃; and the main engine speed of the twin-screw extruder is 200-1000 r / min.

8. The use of a polyamide composition material for automotive air conditioning pipes as described in any one of claims 1-5 in the preparation of automotive air conditioning pipes.

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