A semi-aromatic polyamide composite material, a preparation method and application thereof

Abstract

The application discloses a kind of semi-aromatic polyamide composite materials, by weight parts, including the following components: semi-aromatic polyamide 79-101 parts;Maleic anhydride grafting type toughening agent 5-30 parts;Amine electrolyte-resistant modifier 4-8 parts;Ethylene-vinyl alcohol copolymer 2-5 parts.Semi-aromatic polyamide composite material of the application has the advantages that good cooling liquid and electrolyte-resistant, and has the elongation at break of >150%, and is suitable for the preparation of new energy vehicle liquid cooling pipe.

Description

Technical Field

[0001] This invention relates to the field of polymer materials technology, and in particular to a semi-aromatic polyamide composite material, its preparation method, and its application. Background Technology

[0002] The fundamental changes in the power systems of new energy vehicles, especially pure electric vehicles, are reshaping the thermal management system architecture of automobiles. Compared to traditional fuel vehicles, electric vehicles need to further improve their thermal management efficiency. New energy vehicle cooling systems can be categorized by cooling medium into air cooling, liquid cooling, and phase change materials. Liquid cooling is currently the primary cooling method for new energy vehicles, including water cooling and oil cooling. As a crucial component of new energy vehicles, coolant piping needs to meet various requirements, including resistance to hydrolysis, oil, high temperatures, and lightweight design. In particular, when the battery leaks, the coolant piping needs to be resistant to electrolyte leakage to effectively prevent battery short circuits and fires caused by electrolyte leakage.

[0003] Currently, rubber hoses are rarely used due to their poor environmental adaptability or low cooling efficiency. Silicone hoses, for example, have low cooling efficiency, are heavy, and are prone to aging. Nylon hoses, due to their light weight and simple processing, have gradually become the main material used in coolant piping. Nylons used in coolant piping are mainly aliphatic and aromatic. Aliphatic nylons are represented by PA11, PA12, and PA612, while aromatic nylons are represented by PA9T and PA11T. Nylon plastic tubing can be used in motor compartments, chassis, and battery packs. The appropriate temperature resistance rating and structural type of nylon material are selected based on the different temperature, pressure, and assembly requirements of each location. However, these aliphatic nylons are not very resistant to coolants and electrolytes, and often need to be made into multi-layer structures. For example, PA11 and PA12 materials need to be made into three- or five-layer pipelines with barrier materials such as EVOH, ETFE, and EFEP to meet the requirements of long-term use. PA612 has even worse resistance to hydrolysis and alcoholysis, and can only be used as a cost reduction solution for PA11 and PA12, and is currently rarely used.

[0004] Meanwhile, for cooling pipes used in new energy electric vehicles, elongation at break is a key indicator of pipe materials, closely related to the elongation, burst, and dynamic fatigue performance of the molded pipes. It is generally believed in the industry that an elongation at break >150% is necessary to meet the requirements of elongation, burst, and dynamic fatigue testing for pipes, ensuring the production of qualified pipes; while when the elongation at break <20%, the material's service life has reached its limit. Therefore, testing the initial and coolant-resistant elongation at break can indicate whether the polyamide composition is suitable for pipes.

[0005] Patent CN118063957A discloses a flexible, hydrolysis-resistant extruded polyamide material, mainly comprising 20-52% polyamide resin, 20-50% polyphenylene ether resin, 3-7% compatibilizer, 8-14% toughening agent, 10-14% composite plasticizer, 0.3-0.6% antioxidant, and 0.4-0.7% lubricant. This patent primarily uses aliphatic polyamides such as PA6 and PA612 as the resin matrix, which exhibits poor electrolyte resistance. Summary of the Invention

[0006] The purpose of this invention is to provide a semi-aromatic polyamide composite material with good resistance to coolant and electrolyte and high elongation at break, as well as its preparation method and application.

[0007] This invention is achieved through the following technical solution:

[0008] A semi-aromatic polyamide composite material, characterized in that, by weight, it comprises the following components:

[0009] 79-101 parts of semi-aromatic polyamide;

[0010] 5-30 parts of maleic anhydride grafted toughening agent;

[0011] 4-8 parts of amine-based electrolyte-resistant modifier;

[0012] 2-5 parts of ethylene-vinyl alcohol copolymer;

[0013] The semi-aromatic polyamide, in molar percentage, is derived from the following units:

[0014] The diacid unit is derived from terephthalic acid and a straight-chain diacid containing at least 10 carbon atoms, wherein terephthalic acid accounts for 55-85 mol% of the diacid unit molar content, and the straight-chain diacid containing at least 10 carbon atoms is selected from at least one of 1,10-decanedioic acid, 1,12-dodecanoic acid, and 1,18-octadecanoic acid, wherein 1,10-decanedioic acid accounts for 50-100 mol% of the total molar percentage content of the straight-chain diacid containing at least 10 carbon atoms.

[0015] The diamine units are derived from 1,10-decanediamine and 1,12-dodecanediamine, with 1,10-decanediamine accounting for 50-100 mol% of the total diamine units.

[0016] The amine electrolyte-resistant modifier is selected from at least one of N-ethyl-p-toluenesulfonamide, dendritic polyamide amine, 4,4'-methylenebis(3-chloro-2,6-diethylaniline), N,N'-bis(2,6-diisopropylphenyl)carbodiimide, and diethyltoluenediamine.

[0017] In the semi-aromatic polyamide composite material of the present invention, the content of semi-aromatic polyamide can be 79 parts, 81 parts, 83 parts, 85 parts, 87 parts, 89 parts, 91 parts, 93 parts, 95 parts, 97 parts, 99 parts, or 101 parts; the content of maleic anhydride grafted toughening agent can be 5 parts, 7 parts, 9 parts, 11 parts, 13 parts, 15 parts, 17 parts, 19 parts, 21 parts, 23 parts, 25 parts, 27 parts, 29 parts, or 30 parts; the content of amine electrolyte-resistant modifier can be 4 parts, 4.5 parts, 5 parts, 5.5 parts, 6 parts, 6.5 parts, 7 parts, 7.5 parts, or 8 parts; and the content of ethylene-vinyl alcohol copolymer can be 2 parts, 2.5 parts, 3 parts, 3.5 parts, 4 parts, 4.5 parts, or 5 parts.

[0018] The molar content of ethylene in the ethylene-vinyl alcohol copolymer of the present invention can be in the range of 20-45 mol.

[0019] In the semi-aromatic polyamide composite material of the present invention, the semi-aromatic polyamide accounts for not less than 60 wt% of the total weight.

[0020] Preferably, terephthalic acid accounts for 65-75 mol% of the diacid unit.

[0021] Preferably, the amine electrolyte-resistant modifier is selected from at least one of N-ethyl-p-toluenesulfonamide and dendritic polyamide amine.

[0022] More preferably, the amine-based electrolyte-resistant modifier is selected from dendritic polyamide amines.

[0023] The maleic anhydride-grafted toughening agent is selected from at least one of maleic anhydride-grafted POE, maleic anhydride-grafted SEBS, and maleic anhydride-grafted EPDM.

[0024] In the aforementioned maleic anhydride grafted toughening agent, the grafting rate of maleic anhydride is 1-5 wt%.

[0025] Preferably, in the maleic anhydride grafted toughening agent, the grafting rate of maleic anhydride is 2-3 wt%.

[0026] Maleic anhydride grafted toughening agents can be commercially available products or obtained by self-production. Self-production methods include, but are not limited to: mixing initiator (diisopropylbenzene peroxide, benzoyl peroxide), unmodified toughening agent, and maleic anhydride in a designed ratio, and then mixing them in a mixing machine at a temperature range of 180-220°C.

[0027] The test method for maleic anhydride content can be acid-base titration. The specific procedure is as follows: dissolve the copolymer in xylene under reflux. After cooling, add a certain amount of 0.05 mol / L potassium hydroxide-ethanol solution, and then reflux for 8 hours. Using 0.1% phenolphthalein solution as an indicator, titrate with 0.05 mol / L HCl-isopropanol solution while hot to the endpoint. The weight content G is calculated using the following formula:

[0028] G = (N1 × Vl - N2 × V2) × M ÷ w ÷ 10

[0029] In the formula: N1: KOH—equivalent concentration of ethanol solution, N;

[0030] V1: Volume of KOH ethanol solution, ml;

[0031] N2: Equivalent concentration of HCl-isopropanol solution, N;

[0032] V2: Volume of HCl-isopropanol solution, in ml;

[0033] M: Equivalent mass of maleic anhydride, g;

[0034] w: Mass of the dried sample after extraction, in g.

[0035] The relative viscosity range of the semi-aromatic polyamide is 2.4-3.2. The test method is as follows: refer to GB12006.1-89, method for determining the viscosity of polyamide; the specific test method is: measure the relative viscosity ηr of polyamide with a concentration of 0.25 g / dl in 98% concentrated sulfuric acid at 25±0.01℃.

[0036] The semi-aromatic polyamide of the present invention can be a commercially available product or can be obtained by self-production. The self-production method includes, but is not limited to: adding the reaction monomer, benzoic acid, sodium hypophosphite and deionized water to a pressure vessel; the amount of benzoic acid is 1-3% of the total amount of diamine and diacid, the weight of sodium hypophosphite is 0.05-0.15% of the total weight of the other ingredients excluding deionized water, and the weight of deionized water is 20-40% of the total weight of the ingredients; evacuating and filling with high-purity nitrogen as a protective gas, heating to 190-210°C within 1.5-2.5 hours under stirring, stirring the reaction mixture at 190-210°C for 0.5-1.5 hours, and then raising the temperature of the reactants to 260-280°C under stirring; continuing the reaction at 260-280°C and a constant pressure of 3.0-3.4 MPa for 1-3 hours, maintaining a constant pressure by removing the formed water, and then gradually reducing the pressure to atmospheric pressure. After the reaction is completed, the product is discharged to obtain the polyamide resin. Depending on actual needs, 0-3 parts of additives may be added, wherein the additives are selected from at least one of UV stabilizers, heat stabilizers, and pigments.

[0037] The melting point range of the semi-aromatic polyamide of this invention is 250-290℃. It was tested using a differential scanning calorimeter (DSC) according to ISO 11357-3-2018 standard.

[0038] The preparation method of the semi-aromatic polyamide composite material of the present invention includes the following steps: mixing each component evenly according to the formula, and extruding and granulating it through a twin-screw extruder to obtain the semi-aromatic polyamide composite material.

[0039] The application of the semi-aromatic polyamide composite material of the present invention is for the preparation of liquid cooling pipelines.

[0040] The present invention has the following beneficial effects:

[0041] First, this invention copolymerizes diacid monomers with aromatic benzene rings with long-chain diacid and diamine monomers, and controls the molar ratio to regulate the proportion of diamine and diacid units, thereby obtaining long-chain semi-aromatic polyamides with specific structures. The long carbon chain structure in the molecular chain provides the resin with high toughness and easy processing properties; simultaneously, the benzene ring structure in the molecular chain provides the material with excellent chemical resistance.

[0042] Secondly, in this invention, by using amine-based electrolyte-resistant modifiers, it was found that the toughness and chemical resistance of the composite material were further improved. This is because, on the one hand, amine-based electrolyte-resistant modifiers can combine with the amino groups on the polyamide molecular chains to form hydrogen bonds, thereby reducing the interaction between molecular chains, improving the mobility of the molecular chains, increasing flexibility, and thus improving the toughness of the material; on the other hand, amine-based electrolyte-resistant modifiers can combine with acidic substances in the electrolyte that have penetrated into the material, thereby reducing the acid degradation caused by the attack of carboxyl groups on the polyamide molecular chains, thus improving the electrolyte resistance of the material.

[0043] Third, by adding ethylene-vinyl alcohol copolymer, the present invention utilizes the good chemical resistance of ethylene-vinyl alcohol copolymer itself and the barrier layer formed by orientation inside the material to increase the penetration path of electrolyte, thereby weakening the attack of electrolyte on the molecular chain inside the material and further improving the electrolyte resistance of the material. Detailed Implementation

[0044] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. 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. These all fall within the scope of protection of the present invention.

[0045] The raw materials used in this invention are sourced from the following sources:

[0046] The following polyamide resins were obtained in-house:

[0047] A-1 A-2 A-3 A-4 A-5 A-6 A-7 terephthalic acid mol 5.5 6.5 7.0 7.5 8.5 5.0 9.0 1,10-Sebacic acid mol 4.5 3.5 3.0 2.5 1.5 5.0 1.0 1,10-decanediamine mol 10 10 10 10 10 10 10 Melting point, °C 258 263 265 273 286 252 292 relative viscosity 2.5 2.6 2.6 2.7 2.5 2.6 2.6

[0048] B-1 B-2 B-3 B-4 B-5 B-6 terephthalic acid mol 7.0 7.0 5.5 7.0 7.0 5.5 1,10-Sebacic acid mol 1.5 1.5 3.0 1.0 1.5 3.0 1,12-Dodecanedioic acid mol 1.5 1.5 2.0 1.5 1.5 1,18-octadecanoic acid mol 1.5 1,10-decanediamine mol 5.0 5.0 7.0 5.0 3.0 1,12-Dodecanediamine mol 5.0 5.0 3.0 5.0 7.0 10 Melting point, °C 260 258 253 259 252 250 relative viscosity 2.6 2.6 2.6 2.5 2.6 2.7

[0049] N-Ethyl-p-Toluenesulfonamide: NEO / PTSA, Shouguang Nuomeng Chemical Co., Ltd.;

[0050] Dendritic polyamide amine: CYD-120C, Weihai Chenyuan Molecular New Materials Co., Ltd.;

[0051] 4,4'-Methylenebis(3-chloro-2,6-diethylaniline): MCDEA, Jinwotai Chemical Co., Ltd.;

[0052] N,N'-Di(2,6-Diisopropylphenyl)carbodiimide: BCM-011, Zhejiang Pukang Chemical Co., Ltd.;

[0053] Diethyltoluenediamine: E-100, Shandong Tonglan Chemical Co., Ltd.;

[0054] Ethylene-vinyl alcohol copolymer A: EVOH F101B, Kuraray Corporation, Japan;

[0055] Ethylene-vinyl alcohol copolymer B: OHBX-228, DuPont, USA;

[0056] Maleic anhydride-grafted POE-1: Maleic anhydride grafting rate of 1wt%, prepared by mixing;

[0057] Maleic anhydride-grafted POE-2: Maleic anhydride grafting rate of 2wt%, prepared by mixing;

[0058] Maleic anhydride-grafted POE-3: Maleic anhydride grafting rate of 3wt%, prepared by mixing;

[0059] Maleic anhydride-grafted POE-4: Maleic anhydride grafting rate of 5wt%, prepared by mixing;

[0060] The POE grafted with maleic anhydride mentioned above is derived from POE DF640, Mitsui Chemicals, Singapore.

[0061] Maleic anhydride-grafted SEBS: The maleic anhydride grafting rate is 2.5 wt%, and it is produced in-house through compounding. The SEBS is derived from Kraton G1652, Shell, USA.

[0062] Maleic anhydride-grafted EPDM: The maleic anhydride grafting rate is 2.5 wt%. The maleic anhydride grafting rate is increased by mixing and self-production. The maleic anhydride-grafted EPDM before further modification is derived from FUSABOND N416, DuPont, USA.

[0063] GMA grafted POE: POG-2821, Guangzhou Dongjin Plastics Technology Co., Ltd.;

[0064] GMA grafted SEBS: KT-2511, Shenyang Ketong Company;

[0065] POE: POE DF640, Mitsui Chemicals, Singapore.

[0066] Antioxidant: RIANOX 1098, Lianlong Company;

[0067] Carbon black: M717, Cabot Corporation;

[0068] Test methods:

[0069] (1) Coolant resistance: First, the initial elongation at break was tested. The semi-aromatic polyamide composition was heated and melted at 260~300℃ and injection molded into tensile specimens A and B. The tensile properties of specimen A were tested according to the international standard ISO 527-2019 to obtain the initial elongation at break. Specimen B was placed in an autoclave, and ethylene glycol and deionized water were mixed evenly at a volume ratio of 1:1 and poured into the autoclave until the tensile specimen was completely submerged. Then, the autoclave was placed in a high-temperature oven at 135℃ for 2000h and then taken out. The tensile properties of the aged tensile specimens were tested according to the international standard ISO 527-2019 to obtain the elongation at break after aging. The method for calculating the coolant resistance retention rate is: elongation at break after coolant test / initial elongation at break × 100%.

[0070] (2) Electrolyte resistance: First, the initial elongation at break was tested. The semi-aromatic polyamide composition was heated and melted at 260~300℃ and injection molded into tensile specimens A and B. The tensile properties of specimen A were tested according to the international standard ISO 527-2019 to obtain the initial elongation at break. Specimen B was placed in a sealed glass container, and the electrolyte (EC / EMC / DMC (volume ratio 1:1:1) mixed solvent system, with LiPF6 as the electrolyte and a concentration of 1.5mol / L) was poured into the container until the tensile specimen was completely submerged. Then, the container was placed in an 85℃ high-temperature oven for 2000h and taken out. The tensile properties of the aged tensile specimens were tested according to the international standard ISO 527-2019 to obtain the elongation at break after aging. The method for calculating the electrolyte resistance retention rate is: elongation at break after electrolyte test / initial elongation at break × 100%.

[0071] Table 1: Component content and test results of semi-aromatic polyamide composites in Examples 1-6

[0072] Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Polyamide resin A-1 80 90 100 90 90 90 Maleic anhydride grafted onto POE-1 5 15 30 Maleic anhydride grafted onto POE-2 15 Maleic anhydride grafted onto POE-3 15 Maleic anhydride grafted onto POE-4 15 N-Ethyl-p-toluenesulfonamide 4 6 8 6 6 6 Ethylene-vinyl alcohol copolymer A 2 3 5 3 3 3 antioxidants 0.5 carbon black 0.4 Initial elongation at break % 158 182 196 192 199 196 Coolant retention rate % 39 39 42 43 43 38 Electrolyte retention rate % 27 30 30 32 30 28

[0073] As can be seen from Examples 2 / 4-6, the retention rate of coolant and electrolyte is higher when the maleic anhydride content is optimized.

[0074] Table 2: Component content and test results of semi-aromatic polyamide composites in Examples 7-12

[0075] Example 7 Example 8 Example 9 Example 10 Example 11 Example 12 Polyamide resin grade A-1 A-1 A-2 A-3 A-4 A-5 polyamide resin content 90 90 90 90 90 90 Maleic anhydride grafted onto POE-1 15 15 15 15 maleic anhydride grafted SEBS 15 Maleic anhydride grafted onto EPDM 15 N-Ethyl-p-toluenesulfonamide 6 6 6 6 6 6 Ethylene-vinyl alcohol copolymer A 3 3 3 3 3 3 Initial elongation at break % 173 172 176 168 159 152 Coolant retention rate % 36 38 42 44 45 47 Electrolyte retention rate % 28 28 32 34 35 36

[0076] As can be seen from Examples 2 / 9-12, the resistance to coolant and electrolyte increases with the increase of benzene ring content. Combined with the initial elongation at break, the preferred molar content of terephthalic acid in the diacid unit is 65-75 mol.

[0077] Table 3: Component content and test results of semi-aromatic polyamide composites in Examples 13-16

[0078] Example 13 Example 14 Example 15 Example 16 Polyamide resin grade B-1 B-2 B-3 A-1 polyamide resin content 90 90 90 90 Maleic anhydride grafted onto POE-1 15 15 15 15 N-Ethyl-p-toluenesulfonamide 6 6 6 6 Ethylene-vinyl alcohol copolymer A 3 3 3 Ethylene-vinyl alcohol copolymer B 3 Initial elongation at break % 172 175 192 180 Coolant retention rate % 42 41 38 38 Electrolyte retention rate % 30 30 28 29

[0079] Table 4: Component content and test results of semi-aromatic polyamide composites in Examples 17-20

[0080] Example 17 Example 18 Example 19 Example 20 Polyamide resin A-1 90 90 90 90 Maleic anhydride grafted onto POE-1 15 15 15 15 Dendritic polyamide 6 4,4'-Methylenebis(3-chloro-2,6-diethylaniline) 6 N,N'-Di(2,6-diisopropylphenyl)carbodiimide 6 Diethyltoluenediamine 6 Ethylene-vinyl alcohol copolymer A 3 3 3 3 Initial elongation at break % 177 175 177 178 Coolant retention rate % 42 35 36 37 Electrolyte retention rate % 34 26 27 29

[0081] As can be seen from Examples 2 / 17-20, the preferred amine-based electrolyte-resistant modifier exhibits better coolant retention rate and electrolyte retention rate.

[0082] As can be seen from the above embodiments, the initial elongation at break of the semi-aromatic polyamide composite material of the present invention is >150%, the elongation at break after aging in coolant for 2000h is >34%, and the elongation at break after aging in electrolyte for 2000h is >25%.

[0083] Table 5: Component content and test results of semi-aromatic polyamide composites in Comparative Examples 1-5

[0084] Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Polyamide resin grade A-1 A-1 A-1 A-1 A-1 polyamide resin content 90 90 90 90 90 Maleic anhydride grafted onto POE-1 15 15 GMA grafted POE 15 GMA grafted with SEBS 15 POE 15 N-Ethyl-p-toluenesulfonamide 6 6 6 2 10 Ethylene-vinyl alcohol copolymer A 3 3 3 3 3 Initial elongation at break % 122 105 110 163 205 Coolant retention rate % 27 26 22 31 35 Electrolyte retention rate % 17 15 17 22 23

[0085] As can be seen from Comparative Examples 1-3, although the GMA-grafted toughening agent can also react with the end groups of polyamide compared to the ungrafted toughening agent, its effect on improving resistance to coolant and electrolyte is not significant enough.

[0086] As can be seen from Comparative Example 4 / 5, when the content of amine-based electrolyte-resistant modifier is too low or too high, it is impossible to simultaneously possess excellent coolant and electrolyte resistance properties.

[0087] Table 6: Component content and test results of semi-aromatic polyamide composites in Comparative Examples 6-12

[0088] Comparative Example 6 Comparative Example 7 Comparative Example 8 Comparative Example 9 Comparative Example 10 Comparative Example 11 Comparative Example 12 Polyamide resin grade A-1 A-5 A-6 A-7 B-4 B-5 B-6 polyamide resin content 90 90 90 90 90 90 90 Maleic anhydride grafted onto POE-1 15 15 15 15 15 15 15 N-Ethyl-p-toluenesulfonamide 6 6 6 6 6 6 6 Ethylene-vinyl alcohol copolymer A 0 10 3 3 3 3 3 Initial elongation at break % 188 136 192 126 187 195 198 Coolant retention rate % 36 43 33 50 34 35 32 Electrolyte retention rate % 20 32 24 38 24 21 22

[0089] Comparative Example 6 shows that the electrolyte resistance is insufficient when ethylene-vinyl alcohol copolymer is not present.

[0090] As shown in Comparative Example 7, when the content of ethylene-vinyl alcohol copolymer is too high, the initial elongation at break is too low.

[0091] As shown in Comparative Example 8, when the terephthalic acid content in the polyamide resin is too low, the retention rate of coolant and electrolyte resistance is low.

[0092] As shown in Comparative Example 9, when the terephthalic acid content in the polyamide resin is too high, the initial elongation at break is too low, making it unsuitable for manufacturing pipelines.

[0093] As shown in Comparative Example 10, even if the terephthalic acid content in the polyamide resin is within the specified range, the retention rate of coolant and electrolyte resistance is low when the proportion of 1,10-sebacic acid is too low.

[0094] As shown in Comparative Example 11 / 12, when the content of decanediamine is too low or even absent, the electrolyte retention rate is low.

Claims

1. A semi-aromatic polyamide composite material, characterized in that, By weight, it includes the following components: 79-101 parts of semi-aromatic polyamide; 5-30 parts of maleic anhydride grafted toughening agent; 4-8 parts of amine-based electrolyte-resistant modifier; 2-5 parts of ethylene-vinyl alcohol copolymer; The semi-aromatic polyamide, in molar percentage, is derived from the following units: The diacid unit is derived from terephthalic acid and a straight-chain diacid containing at least 10 carbon atoms, wherein terephthalic acid accounts for 55-85 mol% of the diacid unit molar content, and the straight-chain diacid containing at least 10 carbon atoms is selected from at least one of 1,10-decanedioic acid, 1,12-dodecanoic acid, and 1,18-octadecanoic acid, wherein 1,10-decanedioic acid accounts for 50-100 mol% of the total molar percentage content of the straight-chain diacid containing at least 10 carbon atoms. The diamine units are derived from 1,10-decanediamine and 1,12-dodecanediamine, with 1,10-decanediamine accounting for 50-100 mol% of the total diamine units. The amine electrolyte-resistant modifier is selected from at least one of N-ethyl-p-toluenesulfonamide, dendritic polyamide amine, 4,4'-methylenebis(3-chloro-2,6-diethylaniline), N,N'-bis(2,6-diisopropylphenyl)carbodiimide, and diethyltoluenediamine.

2. The semi-aromatic polyamide composite material according to claim 1, characterized in that, The amine electrolyte-resistant modifier is selected from at least one of N-ethyl-p-toluenesulfonamide and dendritic polyamide amine.

3. The semi-aromatic polyamide composite material according to claim 2, characterized in that, The amine-based electrolyte-resistant modifier is selected from dendritic polyamide amines.

4. The semi-aromatic polyamide composite material according to claim 2, characterized in that, Terephthalic acid accounts for 65-75 mol of the diacid unit.

5. The semi-aromatic polyamide composite material according to claim 1, characterized in that, The maleic anhydride-grafted toughening agent is selected from at least one of maleic anhydride-grafted POE, maleic anhydride-grafted SEBS, and maleic anhydride-grafted EPDM.

6. The semi-aromatic polyamide composite material according to claim 1, characterized in that, In the aforementioned maleic anhydride grafted toughening agent, the grafting rate of maleic anhydride is 1-5 wt%.

7. The semi-aromatic polyamide composite material according to claim 6, characterized in that, In the aforementioned maleic anhydride grafted toughening agent, the grafting rate of maleic anhydride is 2-3 wt%.

8. The semi-aromatic polyamide composite material according to claim 1, characterized in that, The relative viscosity range of the semi-aromatic polyamide is 2.4-3.

2. It is tested according to GB12006.1-89, the method for determining the viscosity of polyamide. The specific test method is as follows: the relative viscosity ηr of polyamide with a concentration of 0.25 g / dl is measured in 98% concentrated sulfuric acid at 25±0.01℃.

9. The semi-aromatic polyamide composite material according to claim 1, characterized in that, The product also includes 0-3 parts by weight of additives, wherein the additives are selected from at least one of UV stabilizers, heat stabilizers, and pigments.

10. A method for preparing the semi-aromatic polyamide composite material according to any one of claims 1-9, characterized in that, The process includes the following steps: mixing the components evenly according to the formula, and granulating them by extrusion through a twin-screw extruder to obtain a semi-aromatic polyamide composite material.

11. The application of the semi-aromatic polyamide composite material according to any one of claims 1-9, characterized in that, Used for manufacturing liquid cooling pipelines.

12. A pipe prepared using any one of the semi-aromatic polyamide composite materials according to claims 1-9.