High-temperature-resistant and cooling-liquid-resistant flexible pipeline PA612 material and preparation method thereof
By optimizing the composition and preparation process of PA612 material, a stable three-dimensional network structure and surface barrier layer are formed, which solves the performance degradation problem of traditional PA612 material in high-temperature coolant environment, realizes the long-term heat aging resistance and coolant resistance performance of the material, and has excellent flame retardant properties and low-temperature flexibility.
Patent Information
- Application Number
- CN202511496024.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-10-20
- Publication Date
- 2025-12-16
AI Technical Summary
Traditional PA612 materials exhibit insufficient resistance to thermo-oxidative aging and hydrolysis under high temperature and coolant environments, resulting in decreased mechanical properties and poor dimensional stability, which limits their application in high-end automotive cooling systems.
By adding specific components such as barrier agents, hydrolysis resistant agents, hindered phenolic antioxidants, phosphite antioxidants, lignite wax, nylon masterbatch, DCP-40, powdered TAIC, flame retardants, maleic anhydride grafted elastomers, and N-butylbenzene cycloamide plasticizers, a stable three-dimensional network structure and surface barrier layer are formed. Combined with self-synthesized reactive flame retardants, the preparation process is optimized to improve material performance.
It achieves significant improvements in the material's long-term heat aging resistance and coolant resistance at high temperatures, maintains good mechanical integrity and low-temperature flexibility, and also possesses excellent flame retardant properties, making it suitable for flexible piping applications in high-temperature, high-humidity, and coolant environments.
Smart Images
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Abstract
Description
Technical Field
[0001] This invention belongs to the field of polymer materials technology, specifically relating to a high-temperature resistant and coolant-resistant flexible pipeline PA612 material and its preparation method. Background Technology
[0002] Polyamide 612 (PA612) has a broad application base in automotive cooling system piping due to its good mechanical properties, chemical corrosion resistance, and low water absorption. However, as the automotive industry develops towards higher efficiency and higher power density, the ambient temperature in the engine compartment has increased significantly, placing more stringent demands on cooling systems. Their operating temperature range has generally increased to 125°C or even higher. Under these harsh conditions, traditional PA612 materials exhibit significant performance limitations: prolonged exposure to high temperatures makes the material susceptible to thermo-oxidative aging, leading to a significant decline in mechanical properties; simultaneously, during continuous contact with high-temperature coolant, the material's insufficient resistance to hydrolysis easily triggers molecular chain degradation, accompanied by significant swelling, resulting in a decrease in key mechanical properties and poor dimensional stability. These inherent defects severely restrict the reliable application and long-term development of traditional PA612 materials in high-end and next-generation automotive cooling piping systems.
[0003] Therefore, developing a PA612 material that combines excellent long-term high-temperature resistance and coolant resistance has become a key issue that urgently needs to be addressed in this technical field. Summary of the Invention
[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a high-temperature resistant and coolant-resistant flexible pipeline PA612 material and its preparation method.
[0005] The objective of this invention can be achieved through the following technical solutions: A method for preparing a high-temperature resistant and coolant-resistant flexible piping PA612 material includes the following steps: Step 1: Add PA612, barrier agent, hydrolysis resistant agent, hindered phenolic antioxidant 1790, phosphite antioxidant 168, lignite wax, nylon color masterbatch, DCP-40, powdered TAIC, and flame retardant to a high-speed mixer and mix for 5-8 minutes to obtain a premix. Step 2: The premixed material is melt-blended with maleic anhydride grafted elastomer and N-butylbenzene cycloamide plasticizer, extruded, granulated, and then injection molded after drying to obtain PA612 material.
[0006] More preferably, the premix comprises the following components by weight: 65-70 parts PA612, 4-8 parts barrier agent, 1-2 parts hydrolysis resistant agent, 0.05-0.2 parts hindered phenolic antioxidant 1790, 0.1-0.3 parts phosphite antioxidant 168, 0.1-0.3 parts lignite wax, 0.5-2 parts nylon masterbatch, 0.1-0.3 parts DCP-40, 0.05-0.1 parts powdered TAIC, 8-10 parts flame retardant, 8-12 parts maleic anhydride grafted elastomer, and 10-15 parts N-butylbenzene cycloamide plasticizer.
[0007] In a more optimized manner, the extrusion temperature is set as follows: Zone 1 220℃, Zone 2 235℃, Zone 3 245℃, Zone 4 250℃, Zone 5 245℃, Zone 6 240℃, Zone 7 240℃, Zone 8 235℃, Zone 9 235℃, Zone 10 230℃, Zone 11 230℃, and the die head 235℃.
[0008] The optimal injection molding process parameters are: injection temperature 235-250℃, mold temperature 70-90℃, and injection pressure 60-80MPa.
[0009] In a more optimized manner, the preparation process of the flame retardant is as follows: S1: Under a protective atmosphere, 4-hydroxybenzaldehyde, triethylamine and dichloromethane were mixed and phenylphosphonodichloro was slowly added dropwise over 30 min in an ice bath at 0 °C. After the addition was complete, the mixture was stirred at room temperature for 20 h. After the reaction was completed, the organic phase was washed sequentially with saturated sodium carbonate solution and saturated brine. Then, the solvent dichloromethane was removed by rotary evaporator. The crude product was dried under vacuum at 50 °C for 12 h to obtain intermediate A. S2: Mix intermediate A, 5-amino-2-benzimidazolone, ethanol and hydrochloric acid, raise the temperature to 80°C, reflux and stir for 8 hours. After the reaction is completed, cool to room temperature, filter, wash and dry to obtain flame retardant.
[0010] In this scheme, 4-hydroxybenzaldehyde first undergoes a nucleophilic substitution reaction with phenylphosphonic dichloro under a low-temperature protective atmosphere. Triethylamine acts as an acid-binding agent to neutralize the generated HCl, yielding an intermediate containing a phosphonate ester and an aldehyde group. Then, under reflux in ethanol, the aldehyde group of the intermediate undergoes a condensation dehydration reaction with the amino group of 5-amino-2-benzimidazolone, forming a stable aromatic Schiff base structure under the catalysis of a small amount of hydrochloric acid, ultimately obtaining the target flame retardant. The specific synthetic process is shown below: In a more optimized manner, the raw materials for preparing intermediate A include the following components: by weight, 37-38 parts of 4-hydroxybenzaldehyde, 31-32 parts of triethylamine, 200-250 parts of dichloromethane, and 30-32 parts of phenylphosphonodichloro.
[0011] In a more optimized manner, the raw materials for preparing the flame retardant include the following components: by weight, 30-32 parts of intermediate A, 24-25 parts of 5-amino-2-benzimidazolone, 500-550 parts of ethanol, and 0.1-0.2 parts of hydrochloric acid; wherein the concentration of hydrochloric acid is 37 wt%.
[0012] The beneficial effects of this invention are: The high-temperature resistant and coolant-resistant flexible piping PA612 material provided by this invention achieves synergistic improvements in multiple properties through component design and preparation process. Its beneficial effects are mainly reflected in the following aspects: The material of this invention exhibits excellent long-term heat aging resistance. The crosslinking system composed of DCP-40 and powdered TAIC works synergistically with the maleic anhydride-grafted elastomer to form a stable three-dimensional network structure between the PA612 molecular chains. This structure not only enhances the binding force between the molecular chains, but more importantly, it provides effective spatial protection for the hydrolysis-sensitive amide bonds, significantly increasing the difficulty of their contact with high-temperature water and oxygen molecules, thereby fundamentally delaying the process of thermo-oxidative aging and hydrolysis reactions.
[0013] Regarding coolant resistance, the material effectively resists coolant erosion through the combined action of a surface barrier layer (a barrier agent migrating to the surface and some small-molecule additives) and an internal stabilizing structure. The hydrophobic barrier layer on the surface greatly inhibits the penetration of small coolant molecules, while the internal cross-linked network limits the material's swelling tendency as a whole. Simultaneously, specific hydrolysis-resistant agents actively neutralize the acidic substances produced by hydrolysis, disrupting its autocatalytic cycle, allowing the material to maintain an extremely low volume change rate and good mechanical integrity even after long-term immersion.
[0014] The material's low-temperature flexibility is ensured through the synergistic plasticization of elastomer toughening and plasticizer. N-Butylbenzenecycloamide plasticizer effectively improves the low-temperature mobility of polymer segments, while maleic anhydride-grafted elastomers act as efficient stress absorption centers, together ensuring that the material still possesses excellent impact resistance and brittle fracture resistance at harsh low temperatures of -30°C.
[0015] Furthermore, the self-synthetic reactive flame retardant used in this invention imparts highly efficient and stable flame-retardant properties to the material. This flame retardant molecule is ingeniously designed, integrating gas-phase and condensed-phase flame-retardant mechanisms: during combustion, it releases phosphorus-containing free radicals, effectively quenching combustion-active free radicals in the gas phase; simultaneously, the benzimidazolone heterocycle and Schiff base structure in its molecule serve as highly stable char-forming cores, promoting the formation of a dense and stable char layer in the condensed phase, which efficiently isolates heat and mass transfer. This synergistic effect of phosphorus-nitrogen heterocycles endows the material with excellent flame retardancy while avoiding negative impacts on its long-term thermal stability and mechanical properties. Detailed Implementation
[0016] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.
[0017] It should be noted that the following parts are by weight, and there are no special restrictions on the manufacturers of the raw materials involved in this invention. For example, in the following embodiments, the barrier agent is MC413, purchased from Nengzhiguang; the hydrolysis resistant agent is HyMax® 213, purchased from Langyi New Materials.
[0018] Example 1: A method for preparing a high-temperature resistant and coolant-resistant flexible piping PA612 material, comprising the following steps: Step 1: Add 65 parts PA612, 4 parts barrier agent, 1 part hydrolysis resistant agent, 0.05 parts hindered phenolic antioxidant 1790, 0.1 parts phosphite antioxidant 168, 0.1 parts lignite wax, 0.5 parts nylon masterbatch, 0.1 parts DCP-40, 0.05 parts powdered TAIC, and 8 parts flame retardant to a high-speed mixer and mix for 5 minutes to obtain a premix. Step 2: The premixed material is melt-blended with 8 parts of maleic anhydride grafted elastomer and 10 parts of N-butylbenzene cycloamide plasticizer, extruded (zone 1 220℃, zone 2 235℃, zone 3 245℃, zone 4 250℃, zone 5 245℃, zone 6 240℃, zone 7 240℃, zone 8 235℃, zone 9 235℃, zone 10 230℃, zone 11 230℃, die head 235℃), granulated, and after drying, injection molded (injection temperature 235℃, mold temperature 70℃, injection pressure 60MPa) to obtain PA612 material; The preparation process of the flame retardant is as follows: S1: Under a protective atmosphere, 37 parts of 4-hydroxybenzaldehyde, 31 parts of triethylamine and 200 parts of dichloromethane were mixed and 30 parts of phenylphosphonic dichloromethane were slowly added dropwise over 30 min in an ice bath at 0 °C. After the addition was complete, the mixture was stirred at room temperature for 20 h. After the reaction was completed, the organic phase was washed sequentially with saturated sodium carbonate solution and saturated brine. Then, the solvent dichloromethane was removed by rotary evaporator. The crude product was dried under vacuum at 50 °C for 12 h to obtain intermediate A. S2: Mix 30 parts of intermediate A, 24 parts of 5-amino-2-benzimidazolone, 500 parts of ethanol and 0.1 parts of hydrochloric acid (concentration of 37wt%), raise the temperature to 80℃, reflux and stir for 8 hours. After the reaction is completed, cool to room temperature, filter, wash and dry to obtain flame retardant.
[0019] Example 2: A method for preparing a high-temperature resistant and coolant-resistant flexible piping PA612 material, comprising the following steps: Step 1: Add 70 parts PA612, 8 parts barrier agent, 2 parts hydrolysis resistant agent, 0.2 parts hindered phenolic antioxidant 1790, 0.3 parts phosphite antioxidant 168, 0.3 parts lignite wax, 2 parts nylon masterbatch, 0.3 parts DCP-40, 0.1 parts powdered TAIC, and 10 parts flame retardant to a high-speed mixer and mix for 8 minutes to obtain a premix. Step 2: The premixed material is melt-blended with 12 parts of maleic anhydride grafted elastomer and 15 parts of N-butylbenzene cycloamide plasticizer, extruded (zone 1 220℃, zone 2 235℃, zone 3 245℃, zone 4 250℃, zone 5 245℃, zone 6 240℃, zone 7 240℃, zone 8 235℃, zone 9 235℃, zone 10 230℃, zone 11 230℃, die head 235℃), granulated, and after drying, injection molded (injection temperature 250℃, mold temperature 90℃, injection pressure 80MPa) to obtain PA612 material; The preparation process of the flame retardant is as follows: S1: Under a protective atmosphere, 38 parts of 4-hydroxybenzaldehyde, 32 parts of triethylamine and 250 parts of dichloromethane were mixed and 32 parts of phenylphosphonic dichloromethane were slowly added dropwise over 30 min in an ice bath at 0 °C. After the addition was complete, the mixture was stirred at room temperature for 20 h. After the reaction was completed, the organic phase was washed sequentially with saturated sodium carbonate solution and saturated brine. Then, the solvent dichloromethane was removed by rotary evaporator. The crude product was dried under vacuum at 50 °C for 12 h to obtain intermediate A. S2: Mix 32 parts of intermediate A, 25 parts of 5-amino-2-benzimidazolone, 550 parts of ethanol and 0.2 parts of hydrochloric acid (concentration of 37wt%), raise the temperature to 80℃, reflux and stir for 8 hours. After the reaction is completed, cool to room temperature, filter, wash and dry to obtain flame retardant.
[0020] Example 3: A method for preparing a high-temperature resistant and coolant-resistant flexible piping PA612 material, comprising the following steps: Step 1: Add 69.68 parts PA612, 5 parts barrier agent, 1.5 parts hydrolysis resistant agent, 0.1 parts hindered phenolic antioxidant 1790, 0.2 parts phosphite antioxidant 168, 0.2 parts lignite wax, 1 part nylon masterbatch, 0.25 parts DCP-40, 0.07 parts powdered TAIC, and 9 parts flame retardant to a high-speed mixer and mix for 6.5 minutes to obtain a premix. Step 2: The premixed material is melt-blended with 10 parts of maleic anhydride grafted elastomer and 12 parts of N-butylbenzene cycloamide plasticizer, extruded (zone 1 220℃, zone 2 235℃, zone 3 245℃, zone 4 250℃, zone 5 245℃, zone 6 240℃, zone 7 240℃, zone 8 235℃, zone 9 235℃, zone 10 230℃, zone 11 230℃, die head 235℃), granulated, and after drying, injection molded (injection temperature 242.5℃, mold temperature 80℃, injection pressure 70MPa) to obtain PA612 material; The preparation process of the flame retardant is as follows: S1: Under a protective atmosphere, 37.5 parts of 4-hydroxybenzaldehyde, 31.5 parts of triethylamine and 225 parts of dichloromethane were mixed and 31 parts of phenylphosphonic dichloromethane were slowly added dropwise over 30 min in an ice bath at 0 °C. After the addition was complete, the mixture was stirred at room temperature for 20 h. After the reaction was completed, the organic phase was washed sequentially with saturated sodium carbonate solution and saturated brine. Then, the solvent dichloromethane was removed by rotary evaporator. The crude product was dried under vacuum at 50 °C for 12 h to obtain intermediate A. S2: Mix 31 parts of intermediate A, 24.5 parts of 5-amino-2-benzimidazolone, 525 parts of ethanol and 0.15 parts of hydrochloric acid (concentration of 37wt%), raise the temperature to 80℃, reflux and stir for 8 hours. After the reaction is completed, cool to room temperature, filter, wash and dry to obtain flame retardant.
[0021] Comparative Example 1: No flame retardant added, as detailed below: A method for preparing a high-temperature resistant and coolant-resistant flexible piping PA612 material includes the following steps: Step 1: Add 69.68 parts PA612, 5 parts barrier agent, 1.5 parts hydrolysis resistant agent, 0.1 parts hindered phenolic antioxidant 1790, 0.2 parts phosphite antioxidant 168, 0.2 parts lignite wax, 1 part nylon masterbatch, 0.25 parts DCP-40, and 0.07 parts powdered TAIC to a high-speed mixer and mix for 6.5 minutes to obtain a premix. Step 2: The premixed material is melt-blended with 10 parts of maleic anhydride grafted elastomer and 12 parts of N-butylbenzene cycloamide plasticizer, extruded (zone 1 220℃, zone 2 235℃, zone 3 245℃, zone 4 250℃, zone 5 245℃, zone 6 240℃, zone 7 240℃, zone 8 235℃, zone 9 235℃, zone 10 230℃, zone 11 230℃, die head 235℃), granulated, and after drying, injection molded (injection temperature 242.5℃, mold temperature 80℃, injection pressure 70MPa) to obtain PA612 material.
[0022] Testing experiment: The materials obtained from the examples and comparative examples were tested, and the data are shown in the table below: Conclusion: This invention successfully developed a high-temperature and coolant-resistant flexible piping material, PA612, and its preparation method. Through reasonable component design and process optimization, the overall performance of the material was significantly improved. Experimental results show that the material exhibits excellent performance in terms of hardness, tensile strength, elongation at break, low-temperature impact strength, and water absorption, especially demonstrating outstanding advantages in flame retardancy. The flame retardant performance of the example is significantly better than that of the comparative example without flame retardant. After rigorous testing with 125°C hot air aging for 1000 hours and G40 coolant at 125°C for 1000 hours, the material still maintains high tensile strength and elongation at break retention, while exhibiting low volume change, demonstrating excellent long-term heat aging resistance and coolant corrosion resistance. This material possesses good low-temperature flexibility and stable mechanical integrity, making it suitable for flexible piping applications in high-temperature, high-humidity, and coolant environments, and has broad application prospects.
[0023] In the description of this specification, the references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.
[0024] The above description is merely an example and illustration of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described, or use similar methods to replace them, as long as they do not deviate from the invention or exceed the scope defined in the claims, all of which should fall within the protection scope of the present invention.
Claims
1. A method for preparing a high-temperature resistant and coolant-resistant flexible piping material PA612, characterized in that, Includes the following steps: Step 1: Add PA612, barrier agent, hydrolysis resistant agent, hindered phenolic antioxidant 1790, phosphite antioxidant 168, lignite wax, nylon color masterbatch, DCP-40, powdered TAIC, and flame retardant to a high-speed mixer and mix for 5-8 minutes to obtain a premix. Step 2: The premixed material is melt-blended with maleic anhydride grafted elastomer and N-butylbenzene cycloamide plasticizer, extruded, granulated, and then injection molded after drying to obtain PA612 material.
2. The method for preparing a high-temperature resistant and coolant-resistant flexible pipeline PA612 material according to claim 1, characterized in that, The premix comprises the following components by weight: 65-70 parts PA612, 4-8 parts barrier agent, 1-2 parts hydrolysis resistant agent, 0.05-0.2 parts hindered phenolic antioxidant 1790, 0.1-0.3 parts phosphite antioxidant 168, 0.1-0.3 parts lignite wax, 0.5-2 parts nylon masterbatch, 0.1-0.3 parts DCP-40, 0.05-0.1 parts powdered TAIC, 8-10 parts flame retardant, 8-12 parts maleic anhydride grafted elastomer, and 10-15 parts N-butylbenzene cycloamide plasticizer.
3. The method for preparing a high-temperature resistant and coolant-resistant flexible pipeline PA612 material according to claim 1, characterized in that, The extrusion temperatures are set as follows: Zone 1 220℃, Zone 2 235℃, Zone 3 245℃, Zone 4 250℃, Zone 5 245℃, Zone 6 240℃, Zone 7 240℃, Zone 8 235℃, Zone 9 235℃, Zone 10 230℃, Zone 11 230℃, and the die head 235℃.
4. The preparation method of PA612 material for high-temperature resistant and coolant-resistant flexible pipelines according to claim 1, characterized in that, The injection molding process parameters are: injection temperature 235-250℃, mold temperature 70-90℃, and injection pressure 60-80MPa.
5. The method for preparing a high-temperature resistant and coolant-resistant flexible pipeline PA612 material according to claim 1, characterized in that, The preparation process of the flame retardant is as follows: S1: Under a protective atmosphere, 4-hydroxybenzaldehyde, triethylamine and dichloromethane were mixed and phenylphosphonodichloro was slowly added dropwise over 30 min in an ice bath at 0 °C. After the addition was complete, the mixture was stirred at room temperature for 20 h. After the reaction was completed, the organic phase was washed sequentially with saturated sodium carbonate solution and saturated brine. Then, the solvent dichloromethane was removed by rotary evaporator. The crude product was dried under vacuum at 50 °C for 12 h to obtain intermediate A. S2: Mix intermediate A, 5-amino-2-benzimidazolone, ethanol and hydrochloric acid, raise the temperature to 80°C, reflux and stir for 8 hours. After the reaction is completed, cool to room temperature, filter, wash and dry to obtain flame retardant.
6. The method for preparing a high-temperature resistant and coolant-resistant flexible pipeline PA612 material according to claim 1, characterized in that, The raw materials for preparing intermediate A include the following components: by weight, 37-38 parts of 4-hydroxybenzaldehyde, 31-32 parts of triethylamine, 200-250 parts of dichloromethane, and 30-32 parts of phenylphosphonic dichloride.
7. The method for preparing a high-temperature resistant and coolant-resistant flexible pipeline PA612 material according to claim 1, characterized in that, The raw materials for preparing the flame retardant include the following components: by weight, 30-32 parts intermediate A, 24-25 parts 5-amino-2-benzimidazole, 500-550 parts ethanol, and 0.1-0.2 parts hydrochloric acid; wherein the concentration of hydrochloric acid is 37 wt%.
8. The PA612 material obtained by the preparation method of the high temperature resistant and coolant resistant flexible pipeline PA612 material according to any one of claims 1-7.