Bio-based polyamide composition material for automobile air conditioner pipe and preparation method of bio-based polyamide composition material

Abstract

The invention relates to the technical field of high polymer materials, in particular to a bio-based polyamide composition material for an automobile air conditioner pipe and a preparation method thereof.The bio-based polyamide composition material for the automobile air conditioner pipe is prepared from, by mass, 30-70 parts of bio-based copolyamide resin, 0-40 parts of PA6 resin and 0-8 parts of plasticizer, the composite material comprises the following components in parts by weight: 15-40 parts of a toughening agent, 0.2-1 part of an antioxidant, 0.2-1 part of a lubricant and 0.1-1 part of a heat stabilizer. According to the method, renewable biomass is adopted as a raw material, the method is green and environment-friendly, the highest bio-based content can reach 62.7%, and the method has very positive significance for reducing carbon emission and reducing the greenhouse effect; and the bio-based copolyamide composition can effectively reduce the permeability of a refrigerant and improve the water absorption rate.

Description

Technical Field

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

[0002] The media permeability of the nylon barrier layer is only 1 / 10 that of the rubber layer, and it exhibits excellent resistance to refrigeration oil. Therefore, nylon is often used as the main material for the anti-leakage barrier layer of air conditioning hoses. Currently, most common automotive air conditioning hoses are aluminum tubes with multi-layer braided rubber / PA6 tubing. However, this type of hose is complex to manufacture, heavy, and prone to refrigerant leakage. Meanwhile, due to the greenhouse effect, automotive air conditioning is being used more frequently and for longer periods. The European F-Gas Directive plans to gradually phase out refrigerant gases with high global warming potential (GWP) from the market. Since January 2017, new cars sold in Europe must be equipped with R1234yf-based air conditioning systems from the outset. Therefore, developing all-plastic automotive air conditioning hose materials based on bio-based polyamide is of great significance for reducing refrigerant leakage and lowering CO2 emissions.

[0003] Patent CN119242031A discloses an automotive air conditioning pipe material and its preparation method. This automotive air conditioning pipe uses a copolyamide as the base material, incorporating an MXD6 structure into the copolyamide resin. The introduction of numerous benzene ring structures into the molecular chain strengthens the intermolecular interactions, resulting in a dense structure that effectively blocks the passage of gas molecules and reduces refrigerant permeation. However, base materials such as PA610 / MXD6, PA612 / MXD6, PA614 / MXD6, PA1010 / MXD6, PA1012 / MXD6, and PA1014 / MXD6 are expensive, and due to their benzene ring structure, they have low water absorption, resulting in weak adhesion to the compressor and easy detachment. Therefore, to expand the development of polyamide in specific application areas, developing bio-based copolyamide compositions for automotive air conditioning pipes with high water absorption and good flexibility is of great significance. Summary of the Invention

[0004] Based on this, the purpose of this invention is to provide a bio-based polyamide composition material for automotive air conditioning pipes and its preparation method. The bio-based content of this bio-based polyamide composition material for automotive air conditioning pipes can reach up to 62.7%, which not only has a very positive significance for reducing carbon emissions and mitigating the greenhouse effect, but also has advantages such as high water absorption and good flexibility.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: The present invention provides a bio-based polyamide composition material for automotive air conditioning pipes, which is prepared from the following components in parts by weight: 30-70 parts of bio-based copolyamide resin, 0-40 parts of PA6 resin, 0-8 parts of plasticizer, 15-40 parts of toughening agent, 0.2-1 parts of antioxidant, 0.2-1 parts of lubricant, and 0.1-1 parts of heat stabilizer.

[0006] As a further improvement to the above-mentioned scheme of the present invention, the bio-based copolyamide resin is obtained by polymerization reaction of one of bio-based PA510 salt and bio-based PA610 salt with bio-based PA56 salt.

[0007] As a further improvement to the above-mentioned scheme of the present invention, the preparation method of the bio-based PA510 salt is as follows: under nitrogen conditions, bio-based 1,5-pentanediamine, bio-based sebacic acid and deionized water are mixed and stirred at 60-80°C to obtain a salt solution of bio-based polyamide 510; wherein, the molar ratio of the bio-based 1,5-pentanediamine and the bio-based sebacic acid is (1-1.2):1.

[0008] As a further improvement to the above-mentioned scheme of the present invention, the preparation method of the bio-based PA610 salt is as follows: under nitrogen conditions, 1,6-hexanediamine, bio-based sebacic acid and deionized water are mixed and stirred at 60-80°C to obtain a salt solution of bio-based polyamide 610; wherein, the molar ratio of the 1,6-hexanediamine and the bio-based sebacic acid is (1-1.2):1.

[0009] As a further improvement to the above-mentioned scheme of the present invention, the preparation method of the bio-based PA56 salt is as follows: under nitrogen conditions, bio-based 1,5-pentanediamine, bio-based adipic acid and deionized water are mixed and stirred at 60-80°C to obtain a salt solution of bio-based polyamide 56; wherein, the molar ratio of the bio-based 1,5-pentanediamine and the bio-based adipic acid is (1-1.2):1.

[0010] As a further improvement to the above-described scheme of the present invention, the 1,5-pentanediamine is produced by bio-fermentation (e.g., by decarboxylation of lysine under the action of decarboxylase). The bio-based sebacic acid is a dicarboxylic acid produced from castor oil through processes such as hydrolysis, pyrolysis, neutralization, decolorization, crystallization, drying, or granulation; the bio-based adipic acid is produced using renewable carbon sources (such as glucose or lignocellulose) through bio-fermentation. The main monomers (bio-based 1,5-pentanediamine, bio-based sebacic acid, and bio-based adipic acid) contain at least a portion of organic carbon from renewable sources that conform to ASTM D6866 standards, thus not relying on petroleum resources and not causing serious environmental pollution, thereby reducing carbon emissions and mitigating the greenhouse effect.

[0011] As a further improvement to the above-mentioned scheme of the present invention, the polymerization reaction method is as follows: one of the bio-based PA510 salt and bio-based PA610 salt is mixed with bio-based PA56 salt to obtain a bio-based copolyamide salt solution. The bio-based copolyamide salt solution is poured into a reaction vessel and heated. When the pressure in the reaction system rises to 0.5-2.0 MPa, the pressure is vented and maintained. After the pressure maintenance is completed, the pressure is reduced until the pressure in the reaction system reaches 0.1-0.25 MPa. The system is then evacuated to a vacuum degree of 0.01-0.08 MPa to obtain a bio-based copolyamide melt. The melt is then pelletized and dried to obtain a bio-based copolyamide resin.

[0012] As a further improvement to the above-described scheme of the present invention, the temperature of the reaction system at the end of the pressure holding is 180-250°C, the temperature of the reaction system at the time of pressure reduction until the pressure of the reaction system reaches 0.1-0.25 MPa is 200-270°C, and the temperature of the reaction system at the time of vacuuming until the vacuum degree reaches 0.01-0.08 MPa is 240-280°C. The pressure is gauge pressure.

[0013] As a further improvement to the above-described scheme of the present invention, in the bio-based copolyamide salt solution, the mass ratio of the bio-based PA56 salt to another bio-based copolyamide salt is 0.5-4:1; the viscosity of the bio-based copolyamide resin is 2.0-4.0; when the viscosity is below 2.0, the mechanical properties of the material are poor, and when the viscosity is above 4.0, the material is difficult to process and mold using existing equipment. Preferably, the viscosity of the bio-based copolyamide resin is 2.4-3.0, more preferably 2.6-2.8. The number average molecular weight of the bio-based copolyamide resin is 20-45 kg / mol, the molecular weight distribution is 1.0-3.0, and the water content is 500-5000 ppm. Preferably, the water content of the bio-based copolyamide resin is 1000-3000 ppm, more preferably 1000-1500 ppm.

[0014] As a further improvement to the above-described scheme of the present invention, the plasticizer is N-butylbenzenesulfonamide; and / or, the toughening agent is at least one of maleic anhydride-grafted POE, ethylene-methyl acrylate-glycidyl methacrylate random terpolymer, and isocyanate resin of ethylene acid copolymer; and / or, the antioxidant is at least one of antioxidant 168, antioxidant N445, antioxidant 1098, and antioxidant S9228; and / or, the lubricant is at least one of silicone powder, lignite wax Wax-OP, vinyl bis-stearamide EBS, and stearate; and / or, the heat stabilizer is at least one of Brügmann H318 and Brügmann H3336.

[0015] The present invention also provides a method for preparing the bio-based polyamide composition material for automotive air conditioning pipes as described above, comprising the following steps: mixing bio-based copolyamide resin, PA6 resin, toughening agent, antioxidant, lubricant, and heat stabilizer in proportion to obtain a mixture; feeding the mixture into zone one of an extruder via a loss-in-weight weighing device; feeding a plasticizer into zone six of the extruder via a liquid metering weighing device in proportion; melting, extruding, granulating, and drying to obtain the bio-based polyamide composition material for automotive air conditioning pipes.

[0016] 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: 210-270℃; Zone 3: 210-270℃; Zone 4: 210-270℃; Zone 5: 210-270℃; Zone 6: 210-270℃; Zone 7: 210-270℃; Zone 8: 210-270℃; Zone 9: 210-270℃; Zone 10: 210-270℃; Die head temperature: 210-270℃; The main rotation speed of the twin-screw extruder is 200-500 r / min.

[0017] Compared with the prior art, the present invention has the following beneficial effects: This invention provides a bio-based copolyamide composition for automotive air conditioning pipes, using renewable biomass as raw material, making it green and environmentally friendly. The bio-based content can reach up to 62.7%, which is of great significance for reducing carbon emissions and mitigating the greenhouse effect. Furthermore, the bio-based copolyamide composition of this invention can effectively reduce refrigerant permeability and increase water absorption. When used to prepare all-plastic polyamide air conditioning pipes, compared with currently common rubber / aluminum pipe combination air conditioning pipes, the bio-based copolyamide composition of this invention reduces weight by 55%, lowers cost by 40%, and significantly reduces refrigerant permeability.

[0018] This invention adds an ionomer sarin resin of ethylene-methyl acrylate-glycidyl methacrylate (PTW) and ethylene acid copolymer to the traditional POE-MAH toughening agent, which has a very good effect on inhibiting refrigerant R1234yf penetration and resisting refrigerant / compressor oil aging.

[0019] The bio-based copolyamide composition for automotive air conditioning pipes provided by this invention, through the synergistic effect of toughening agents and plasticizers, endows the material with excellent flexibility, facilitating pipe installation and meeting the low-temperature operation requirements of -40°C. Simultaneously, through the synergistic effect of antioxidants and heat stabilizers, the material meets the requirements for high-temperature use, especially long-term refrigerant / compressor oil aging. Detailed Implementation

[0020] 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.

[0021] 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.

[0022] The specific information of the raw materials used in the following examples and comparative examples is as follows: (1) Plasticizer BBSA, namely Proviplast 024 from Belgium; (2) Ethylene-methyl acrylate-glycidyl methacrylate random terpolymer, which is DuPont Elvaloy® PTW; (3) The ionomer of ethylene glycol copolymer, Salin resin, is Dow Chemical SURLYN 9910; (4) Maleic anhydride grafted with POE, which is Dow Chemical FUSABOND N493; (5) Silicone powder, purchased from Chengdu Silike Technology, brand name LYSI-300C; (6) Lignite wax, purchased from Clariant Chemicals, brand name WAX-OP; (7) The main antioxidant is a hindered phenolic antioxidant: 4,4'-bis(α,α-dimethylbenzyl)diphenylamine, purchased from Saint-Lecter under the trademark NAUGARD® N445; (8) Auxiliary antioxidants, using phosphite antioxidants: DOWEN's high-temperature auxiliary antioxidant S9228 was selected; (9) Heat stabilizer, purchased from Brüggemann GmbH, Germany, brand name H3336; (10) PA6, purchased from Hangzhou Juhua Shun Co., Ltd., brand name J2700; (11) PA6 / PA66 copolyamide resin, purchased from Hangzhou Juhua Shun Co., Ltd., brand name J400266.

[0023] 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.

[0024] Unless otherwise specified, the reagents, methods and equipment used in this invention are all conventional reagents, methods and equipment in this technical field.

[0025] Preparation Example 1 Preparation of bio-based copolyamide resin 1: Under nitrogen atmosphere, bio-based 1,5-pentanediamine, bio-based adipic acid, and deionized water were mixed evenly, with a molar ratio of 1:1 between bio-based 1,5-pentanediamine and bio-based adipic acid, and stirred at 60°C to obtain a 60% concentration bio-based polyamide 56 salt solution; Under nitrogen atmosphere, bio-based 1,5-pentanediamine, bio-based sebacic acid, and deionized water were mixed evenly, with a molar ratio of 1:1 between bio-based 1,5-pentanediamine and bio-based sebacic acid, and stirred at 60°C to obtain a 50% concentration bio-based polyamide 510 salt solution; The bio-based polyamide 56 salt solution... Bio-based polyamide 510 salt solution was added to the polymerization reactor in a weight ratio of 3:1. The temperature was raised, and when the pressure in the reaction system reached 1.2 MPa, the pressure was vented and maintained for 2 hours. After the pressure maintenance, the temperature of the reaction system was about 245°C. The pressure was then reduced to 0.2 MPa, and the temperature of the reaction system was about 255°C. A vacuum was then drawn to a vacuum degree of 0.01-0.08 MPa and maintained for 1 hour. After the vacuum was drawn, the temperature of the reaction system was about 260°C, and a bio-based copolyamide melt was obtained. The melt was then stretched, granulated, and dried to obtain a bio-based copolyamide resin 1 with a relative viscosity of 2.7.

[0026] Preparation Example 2 Preparation of bio-based copolyamide resin 2: Under nitrogen atmosphere, bio-based 1,5-pentanediamine, bio-based adipic acid, and deionized water were mixed evenly, with a molar ratio of 1:1 between bio-based 1,5-pentanediamine and bio-based adipic acid, and stirred at 60°C to obtain a 60% concentration bio-based polyamide 56 salt solution; Under nitrogen atmosphere, bio-based 1,6-hexanediamine, bio-based sebacic acid, and deionized water were mixed evenly, with a molar ratio of 1:1 between bio-based 1,6-hexanediamine and bio-based sebacic acid, and stirred at 60°C to obtain a 50% concentration bio-based polyamide 610 salt solution; The bio-based polyamide 56 salt solution... Bio-based polyamide 610 salt solution was added to the polymerization reactor in a mass ratio of 4:1, and the temperature was raised. When the pressure in the reaction system reached 1.2 MPa, the pressure was vented and maintained for 2 hours. After the pressure maintenance, the temperature of the reaction system was about 250°C. The pressure was then reduced to 0.2 MPa, and the temperature of the reaction system was about 260°C. The vacuum was then evacuated to a vacuum degree of 0.01-0.08 MPa and maintained for 1 hour. After the vacuum was evacuated, the temperature of the reaction system was about 265°C. A bio-based copolyamide melt was obtained. After being stretched, granulated, and dried, a bio-based copolyamide resin 2 with a relative viscosity of 2.7 was obtained.

[0027] Example 1 This embodiment proposes a bio-based copolyamide composition material for automotive air conditioning pipes, which is prepared from the following components in parts by weight: 62.7 parts bio-based copolyamide resin, 1 part plasticizer BBSA, 22 parts maleic anhydride grafted POE, 8 parts ethylene-methyl acrylate-glycidyl methacrylate, 0.3 parts silicone powder, 0.3 parts lignite wax, 0.2 parts primary antioxidant, 0.2 parts secondary antioxidant, and 0.3 parts heat stabilizer.

[0028] The preparation method of the bio-based copolyamide composition material for automotive air conditioning pipes in this embodiment includes the following steps: Bio-based copolyamide resin 1, maleic anhydride grafted POE, ethylene-methyl acrylate-glycidyl methacrylate, silicone powder, lignite wax, primary antioxidant, secondary antioxidant, and heat stabilizer are added to a high-speed mixer in proportion and mixed for 5 minutes to obtain material one; material one is fed into zone one of a twin-screw extruder through a loss-in-weight weigher, and plasticizer BBSA is fed into zone six of the twin-screw extruder in proportion through a liquid metering weigher; the mixture is melted, extruded, granulated, and dried to obtain the bio-based copolyamide composition material for automotive air conditioning pipes. The twin-screw 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: 180℃, Zone 2: 220℃, Zone 3: 220℃, Zone 4: 230℃, Zone 5: 240℃, Zone 6: 240℃, Zone 7: 250℃, Zone 8: 250℃, Zone 9: 260℃, Zone 10: 260℃; the die head temperature is 260℃; and the main engine speed of the twin-screw extruder is 350 r / min.

[0029] Example 2 The difference between this embodiment and Embodiment 1 is that the bio-based copolyamide composition material for automotive air conditioning pipes in this embodiment is prepared from the following components in parts by weight: 32.7 parts bio-based copolyamide resin 1, 32 parts PA6, 6 parts plasticizer BBSA, 20 parts maleic anhydride grafted POE, 8 parts ethylene-methyl acrylate-glycidyl methacrylate, 0.3 parts silicone powder, 0.3 parts lignite wax, 0.2 parts primary antioxidant, 0.2 parts secondary antioxidant, and 0.3 parts heat stabilizer.

[0030] Example 3 The difference between this embodiment and Embodiment 1 is that the bio-based copolyamide composition material for automotive air conditioning pipes in this embodiment is prepared from the following components in parts by weight: 61.7 parts bio-based copolyamide resin, 1 part plasticizer BBSA, 20 parts maleic anhydride grafted POE, 8 parts ethylene-methyl acrylate-glycidyl methacrylate, 5 parts ionomer of ethylene-acrylic acid copolymer saline resin, 0.3 parts silicone powder, 0.3 parts lignite wax, 0.2 parts primary antioxidant, 0.2 parts secondary antioxidant, and 0.3 parts heat stabilizer.

[0031] Example 4 The difference between this embodiment and Embodiment 1 is that the bio-based copolyamide composition material for automotive air conditioning pipes in this embodiment is prepared from the following components in parts by weight: 30 parts bio-based copolyamide resin 1, 28.7 parts bio-based copolyamide resin 2, 6 parts plasticizer BBSA, 24 parts maleic anhydride grafted POE, 5 parts ethylene-methyl acrylate-glycidyl methacrylate, 5 parts ionomer of ethylene-acrylic acid copolymer saline resin, 0.3 parts silicone powder, 0.3 parts lignite wax, 0.2 parts primary antioxidant, 0.2 parts secondary antioxidant, and 0.3 parts heat stabilizer.

[0032] Example 5 The difference between this embodiment and Embodiment 1 is that the bio-based copolyamide composition material for automotive air conditioning pipes in this embodiment is prepared from the following components in parts by weight: 53.7 parts bio-based copolyamide resin 1, 25 parts maleic anhydride grafted POE, 10 parts ethylene-methyl acrylate-glycidyl methacrylate, 10 parts isocyanate saridin resin of ethylene-acrylic acid copolymer, 0.3 parts silicone powder, 0.3 parts lignite wax, 0.2 parts primary antioxidant, 0.2 parts secondary antioxidant, and 0.3 parts heat stabilizer.

[0033] Comparative Example 1 The difference between this comparative example and Example 1 is that the polyamide composition material of this comparative example is prepared from the following components in parts by weight: 63 parts PA6, 6 parts plasticizer BBSA, 22 parts maleic anhydride grafted POE, 8 parts ethylene-methyl acrylate-glycidyl methacrylate, 0.3 parts silicone powder, 0.3 parts lignite wax, 0.2 parts primary antioxidant, and 0.2 parts secondary antioxidant.

[0034] Comparative Example 2 The difference between this comparative example and Example 1 is that the polyamide composition material of this comparative example is prepared from the following components in parts by weight: 62.7 parts PA6, 32.7 parts PA6 / PA66 copolyamide resin, 6 parts plasticizer BBSA, 20 parts maleic anhydride grafted POE, 8 parts ethylene-methyl acrylate-glycidyl methacrylate, 0.3 parts silicone powder, 0.3 parts lignite wax, 0.2 parts primary antioxidant, 0.2 parts secondary antioxidant, and 0.3 parts heat stabilizer.

[0035] Comparative Example 3 The difference between this comparative example and Example 1 is that the polyamide composition material of this comparative example is prepared from the following components in parts by weight: 62.7 parts of bio-based copolymer polyamide resin 1, 36 parts of maleic anhydride grafted POE, 0.3 parts of silicone powder, 0.3 parts of lignite wax, 0.2 parts of primary antioxidant, 0.2 parts of secondary antioxidant, and 0.3 parts of heat stabilizer.

[0036] The amounts of each component used in Examples 1-5 and Comparative Examples 1-3 are shown in Table 1.

[0037] Table 1. Amounts (parts by mass) of each component in Examples 1-5 and Comparative Examples 1-3

[0038] Test case The polyamide composition materials obtained in Examples 1-5 and Comparative Examples 1-3 were used to manufacture mechanical property test strips: the polyamide composition materials were dried in a vacuum drum drying oven at 110°C for 8 hours to make the moisture content between 500-800 ppm; standard mechanical property test strips were injection molded at a temperature of 270°C; the injection molded mechanical property test strips were placed in a standard laboratory environment (23°C, 50%RH) for 24 hours, and mechanical property tests were performed after the condition was adjusted. The following tests were conducted: Tensile strength was tested according to ISO 527-2, with a specimen size of 170*10*4mm and a test speed of 50mm / min; Elongation at break was tested according to ISO 527-2, with a specimen size of 170*10*4mm and a test speed of 1mm / min; Flexural strength and modulus were tested according to ISO 178-1, with a specimen size of 80*10*4mm and a test speed of 2mm / min; Notched impact performance of simply supported beams was tested according to ISO 1179, with a specimen size of 80*10*4mm and a notch type of 1eA; Melt flow index was tested according to ISO 1133, with test conditions of 230℃-5kg. Refrigerant / compressor oil resistance test: Refrigerant and compressor oil were mixed in a 10:1 ratio, and a 170*10*4mm specimen was immersed in refrigerant / compressor oil PAG at 140℃ for 168 h before testing tensile strength.

[0039] The polyamide compositions obtained in Examples 1-5 and Comparative Examples 1-3 were extruded to form Φ8*1.5mm air conditioning hoses, and then the following performance tests were performed: Permeability measurement: The air conditioning hose is placed at 100℃ for 24 hours and then weighed. The weight is then calculated from the weighing data from 24 hours to 96 hours. The initial weight is the 24-hour weighing data for permeability measurement, and subsequent weighings are performed every 24 hours.

[0040] The high-temperature resistance test method for air conditioning hoses is as follows: the air conditioning hose is bent around a mandrel and placed at 135°C for 168 hours. After that, it is cooled to room temperature, and the surface of the air conditioning hose is observed for cracks. Then, the air conditioning hose is pressurized at 3.5MPa for 5 minutes and then checked for leaks.

[0041] The method for testing low-temperature resistance is as follows: After filling the air conditioning hose with refrigerant, place it in a -40℃ low-temperature chamber for 24 hours. Then, bend the air conditioning hose around the mandrel 180° and observe whether there are cracks or defects on the surface of the air conditioning hose. After recovering the refrigerant, pressurize the air conditioning hose at 3.5MPa for 5 minutes and check for leakage.

[0042] The water absorption rate test method is as follows: the air conditioning hose is filled with 3A molecular sieve and sealed, and placed in an environmental chamber at 85℃ and 85RH for 240h. After the test, the weight of the molecular sieve is weighed and its weight change is calculated. The water absorption rate is obtained by dividing the weight by the surface area of ​​the air conditioning hose.

[0043] Burst pressure: Characterizes the maximum pressure that an air conditioning hose can withstand, and the test shall be conducted in accordance with GB 16897.

[0044] The test results are shown in Table 2.

[0045] Table 2 Performance Test Results

[0046] According to the results in Table 2: Compared with Comparative Example 1, Example 1 used bio-based copolyamide resin 1, and the refrigerant permeability of Example 1 was 5.5 kg / (m²). 2 The annual rate decreased to 1.2 kg / (m²). 2 In [year], it was confirmed that bio-based copolyamide resin can effectively reduce refrigerant permeation. Refrigerant permeation rate is an important factor affecting the cooling effect of air conditioning systems. Low permeation can significantly reduce the frequency of refrigerant refills, reduce the impact of refrigerant on the atmospheric environment, and improve the service life of air conditioning systems. This is one of the key performance characteristics of air conditioning hoses. Furthermore, the water absorption rate of Example 1 increased from 2.5% in Comparative Example 1 to 3.5%. Water absorption rate characterizes the hygroscopicity of the hose. Low hygroscopicity can reduce the oxidation and deterioration of compressor lubricating oil caused by moisture absorption, thereby affecting the cooling effect and causing heat dissipation obstruction, greatly reducing the compressor's service life and the operating effect of the air conditioning system. The flexural modulus of Example 1 decreased from 710 MPa in Comparative Example 1 to 570 MPa, indicating that bio-based copolyamide resin can improve the product's flexibility and greatly improve the assembly adaptability of the parts.

[0047] Compared with Comparative Example 2, Example 2 used a heat stabilizer, which can meet the high temperature resistance requirements, and the bio-based copolyamide resin-based hose has significantly improved burst pressure and refrigerant / compressor oil resistance compared with the traditional PA6 / PA66 copolyamide resin-based hose.

[0048] Compared with Comparative Example 3, Example 3, based on the traditional POE-MAH toughening agent, additionally added ionomer sarin resin of ethylene-methyl acrylate-glycidyl methacrylate PTW and ethylene acid copolymer, which has a very good effect on inhibiting the penetration of refrigerant R1234yf and resisting the aging of refrigerant / compressor oil. After aging at 140°C for 168 hours, the tensile strength of refrigerant / compressor oil increased from 18.4 MPa to 34.4 MPa.

[0049] In summary, Embodiments 1, 2, 3, 4, and 5 of this application exhibit good overall performance and can meet the requirements for air conditioning pipelines in new energy vehicles with low refrigerant permeation and long-term resistance to refrigerant / refrigeration oil aging. Furthermore, their high bio-based content is of great significance in reducing CO2 emissions.

[0050] 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.

[0051] 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 bio-based polyamide composition material for automotive air conditioning pipes, characterized in that, It is prepared from the following components in parts by weight: 30-70 parts of bio-based copolyamide resin, 0-40 parts of PA6 resin, 0-8 parts of plasticizer, 15-40 parts of toughening agent, 0.2-1 parts of antioxidant, 0.2-1 parts of lubricant, and 0.1-1 parts of heat stabilizer.

2. The bio-based polyamide composition material for automotive air conditioning pipes according to claim 1, characterized in that, The bio-based copolyamide resin is obtained by polymerization of one of bio-based PA510 salt and bio-based PA610 salt with bio-based PA56 salt.

3. The bio-based polyamide composition material for automotive air conditioning pipes according to claim 2, characterized in that, The preparation method of the bio-based PA510 salt is as follows: under nitrogen conditions, bio-based 1,5-pentanediamine, bio-based sebacic acid and deionized water are mixed and stirred at 60-80℃ to obtain a salt solution of bio-based polyamide 510; wherein, the molar ratio of the bio-based 1,5-pentanediamine and the bio-based sebacic acid is (1-1.2):

1.

4. The bio-based polyamide composition material for automotive air conditioning pipes according to claim 2, characterized in that, The preparation method of the bio-based PA610 salt is as follows: under nitrogen conditions, 1,6-hexanediamine, bio-based sebacic acid and deionized water are mixed and stirred at 60-80°C to obtain a salt solution of bio-based polyamide 610; wherein, the molar ratio of the 1,6-hexanediamine and the bio-based sebacic acid is (1-1.2):

1.

5. The bio-based polyamide composition material for automotive air conditioning pipes according to claim 2, characterized in that, The preparation method of the bio-based PA56 salt is as follows: under nitrogen conditions, bio-based 1,5-pentanediamine, bio-based adipic acid and deionized water are mixed and stirred at 60-80℃ to obtain a salt solution of bio-based polyamide 56; wherein, the molar ratio of the bio-based 1,5-pentanediamine and the bio-based adipic acid is (1-1.2):

1.

6. The bio-based polyamide composition material for automotive air conditioning pipes according to claim 2, characterized in that, The polymerization reaction method is as follows: one of the bio-based PA510 salt and bio-based PA610 salt is mixed with bio-based PA56 salt to obtain a bio-based copolyamide salt solution. The bio-based copolyamide salt solution is poured into a reaction vessel and heated. When the pressure in the reaction system rises to 0.5-2.0 MPa, the pressure is released and maintained. After the pressure maintenance is completed, the pressure is reduced until the pressure in the reaction system reaches 0.1-0.25 MPa. The system is then evacuated to a vacuum degree of 0.01-0.08 MPa to obtain a bio-based copolyamide melt. The melt is then pelletized and dried to obtain a bio-based copolyamide resin.

7. The bio-based polyamide composition material for automotive air conditioning pipes according to claim 6, characterized in that, When the pressure holding ends, the temperature of the reaction system is 180-250℃. When the pressure is reduced until the pressure of the reaction system reaches 0.1-0.25MPa, the temperature of the reaction system is 200-270℃. When the vacuum is evacuated until the vacuum degree reaches 0.01-0.08MPa, the temperature of the reaction system is 240-280℃.

8. The bio-based polyamide composition material for automotive air conditioning pipes according to claim 6, characterized in that, In the bio-based copolyamide salt solution, the mass ratio of the bio-based PA56 salt to another bio-based copolyamide salt is 0.5-4:1; the viscosity of the bio-based copolyamide resin is 2.0-4.

0.

9. The bio-based polyamide composition material for automotive air conditioning pipes according to claim 1, characterized in that, The plasticizer is N-butylbenzenesulfonamide; and / or, the toughening agent is at least one of maleic anhydride-grafted POE, ethylene-methyl acrylate-glycidyl methacrylate random terpolymer, and isocyanate resin of ethylene-acrylic acid copolymer; and / or, the antioxidant is at least one of antioxidant 168, antioxidant N445, antioxidant 1098, and antioxidant S9228; and / or, the lubricant is at least one of silicone powder, lignite wax, vinyl bis-stearamide, and stearate; and / or, the heat stabilizer is at least one of Brügmann H318 and Brügmann H3336.

10. A method for preparing a bio-based polyamide composition material for automotive air conditioning pipes as described in any one of claims 1-9, characterized in that, It includes the following steps: Bio-based copolyamide resin, PA6 resin, toughening agent, antioxidant, lubricant, and heat stabilizer are mixed in proportion to obtain a mixture. The mixture is fed into zone one of the extruders through a loss-in-weight weigher, and the plasticizer is fed into zone six of the extruders through a liquid metering weigher in proportion. The mixture is melted, extruded, granulated, and dried to obtain a bio-based polyamide composition material for automotive air conditioning pipes.

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