High-temperature-resistant PBT composite material and preparation method thereof

Abstract

The application relates to the technical field of materials, and discloses a high-temperature-resistant PBT composite material and a preparation method thereof.The composite material is prepared through a mixing and melt extrusion process by taking polybutylene terephthalate as a base material and taking a toughening agent and a functional agent as auxiliary materials.The principle that the molecular chains of the functional agent can be connected with the molecular chains of PBT in a chain extension process can greatly increase the density of the PBT molecular chains, and further make the structure of the prepared composite material more compact, so that the mechanical strength of the composite material can be improved, the movement difficulty of the PBT molecular chains can be increased, and the high-temperature resistance of PBT can be improved.In addition, the functional agent has a large number of benzene rings and a rigid heterocyclic structure of norbornene, and further contains a high-energy Si-O structure.The existence of the structures can further enhance the high-temperature resistance of the composite material from the aspects of improving the stability of the PBT molecular chains and increasing the energy required for material decomposition.

Description

Technical Field

[0001] This invention relates to the field of materials technology, specifically to a high-temperature resistant PBT composite material and its preparation method. Background Technology

[0002] Polybutylene terephthalate (PBT) is a thermoplastic polyester material that is widely used in various fields such as electronics, automotive manufacturing, and precision instruments due to its good processability, electrical insulation, and certain heat resistance. However, the performance of PBT materials at high temperatures is not ideal, which limits its application under certain specific high-temperature conditions.

[0003] PBT is prone to oxidation, decomposition, or aging at high temperatures. These reactions damage the molecular structure of the material, thereby reducing its heat resistance and stability. Furthermore, as the temperature increases, the mechanical properties of PBT, such as strength and toughness, degrade, limiting its application in high-temperature environments, particularly in emerging industries like new energy. Therefore, modifying PBT for high-temperature resistance is of great significance for its further development.

[0004] The invention patent with publication number CN114539735B discloses a PBT / POK composite material and its application. By adding polycarbodiimide as a heat resistant agent and a specific compatibilizer, the compatibilizer and heat resistant agent can be used in combination to improve the compatibility between the components and make the prepared composite material have good high-temperature aging resistance. Therefore, the high-temperature resistance of PBT can be improved by starting with the formulation and adding additives with special effects. Summary of the Invention

[0005] (a) Technical problems to be solved

[0006] To address the shortcomings of existing technologies, this invention provides a high-temperature resistant PBT composite material and its preparation method.

[0007] (II) Technical Solution

[0008] A method for preparing a high-temperature resistant PBT composite material, wherein the composite material is made from the following raw materials measured in parts by weight:

[0009] 75-82 parts PBT, 10-15 parts toughening agent, 4-8 parts functional agent, 5-12 parts fiber filler, 0.1-0.4 parts chain extender, 0.1-0.3 parts antioxidant, 0.5-1.5 parts lubricant, 1-2 parts silane coupling agent;

[0010] The preparation method of the PBT composite material includes the following steps:

[0011] Step 1: Weigh out each ingredient according to the specified weight proportions and set aside.

[0012] The second step is to add all the raw materials into the mixing tank, control the temperature at 100-120℃, the stirring rate at 500-1000r / min, and mechanically mix for 10-20 minutes to form a premix.

[0013] The third step is to add the premixed material to a twin-screw extruder for melt extrusion to obtain the composite material.

[0014] As a further aspect of the present invention, the toughening agent is maleic anhydride-grafted POE or maleic anhydride-grafted SEBS.

[0015] As a further aspect of the present invention, the preparation method of the functional agent includes the following steps:

[0016] Step 1: Add 3-hydroxyglutaric acid, 5-norbornen-2-yl(ethyl)chlorodimethylsilane and toluene to a nitrogen-filled reactor, start stirring to form a homogeneous reaction solution, then start heating and gradually increase the temperature to 60-70℃. Add an acid-binding agent while stirring. After the addition is complete, keep the mixture warm and stir for 4-6 hours, then remove the solvent, stop heating, discharge the material, and purify it to obtain the norbornen derivative intermediate.

[0017] Step 2: Add norbornene derivative intermediate, N,N-di(glycidyl)aniline and N,N-dimethylformamide to the polymerization reactor, stir and mix well, purge with nitrogen, then add phase transfer catalyst to the polymerization reactor, turn on heating, control the heating rate at 3-6℃ / min, raise the temperature to 80-100℃, maintain stirring and polymerization at this temperature for 12-18h, stop the reaction, cool down and discharge the material to obtain the functional agent.

[0018] As a further aspect of the present invention, in step one, the molar ratio of 3-hydroxyglutaric acid and 5-norbornen-2-yl(ethyl)chlorodimethylsilane is 1:1.

[0019] As a further aspect of the present invention, in step one, the acid-binding agent is pyridine or triethylamine.

[0020] As a further aspect of the present invention, in step two, the molar ratio of the norbornene derivative intermediate to N,N-bis(glycidyl)aniline is 1-1.2:1.

[0021] As a further aspect of the present invention, in step two, the phase transfer catalyst is any one of tetrabutylammonium bromide, tetrabutylammonium bisulfate, tetramethylammonium bromide, or tetrabutylammonium chloride.

[0022] As a further aspect of the present invention, the fiber filler is at least one of glass fiber, basalt fiber or illite fiber.

[0023] As a further embodiment of the present invention, the chain extender is hydroquinone dihydroxyethyl ether; the antioxidant is at least one of antioxidant BHT, antioxidant 1010, or antioxidant 1076; the lubricant is at least one of polyethylene wax, paraffin wax, or stearic acid; and the silane coupling agent is 3-glycidyl etheroxypropyltrimethoxysilane or 3-glycidyl etheroxypropyltriethoxysilane.

[0024] A high-temperature resistant PBT composite material is prepared using the method described above.

[0025] (III) Beneficial Technical Effects

[0026] This invention modifies PBT by preparing functional agents. Utilizing the principle that the functional agent molecular chains can interconnect with PBT molecular chains during chain extension, the density of the PBT molecular chains is significantly increased, resulting in a more compact composite material structure. This not only improves the mechanical strength of the composite material but also increases the difficulty of PBT molecular chain movement, thereby improving the high-temperature resistance of PBT. Furthermore, the functional agents possess numerous rigid heterocyclic structures such as benzene rings and norbornene, as well as high-bond-energy Si-O structures. The presence of these structures further enhances the high-temperature resistance of the composite material by improving the stability of the PBT molecular chains and increasing the energy required for material decomposition. Attached Figure Description

[0027] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 This is an infrared analysis test image of the functional agent. Detailed Implementation

[0029] To facilitate understanding of the present invention, a more complete description will be provided below. Preferred embodiments of the invention are given below. However, the 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 thorough and complete understanding of the disclosure of the invention.

[0030] Example 1

[0031] A high-temperature resistant PBT composite material, said composite material being made from the following raw materials measured in parts by weight:

[0032] 75 parts PBT, 10 parts toughening agent maleic anhydride grafted POE, 4 parts functional agent, 5 parts fiber filler glass fiber, 0.1 parts chain extender hydroquinone dihydroxyethyl ether, 0.1 parts antioxidant BHT, 0.5 parts lubricant polyethylene wax, 1 part silane coupling agent 3-glycidyl etheroxypropyltriethoxysilane.

[0033] The preparation method of the PBT composite material includes the following steps:

[0034] Step 1: Weigh out each ingredient according to the specified weight proportions and set aside.

[0035] The second step is to add all the raw materials into the mixing tank, control the temperature at 100℃, the stirring speed at 500r / min, and mechanically mix for 20 minutes to form a premix.

[0036] The third step involves adding the premixed material into a twin-screw extruder, controlling the temperatures of zone 1 to be 220℃, zone 2 to be 250℃, zone 3 to be 245℃, zone 4 to be 240℃, zone 5 to be 240℃, zone 6 to be 240℃, zone 7 to be 240℃, zone 8 to be 230℃, and zone 9 to be 220℃, while maintaining the screw speed at 100 rpm, to perform melt extrusion and obtain the composite material.

[0037] Example 2

[0038] A high-temperature resistant PBT composite material, said composite material being made from the following raw materials measured in parts by weight:

[0039] 76 parts PBT, 12 parts toughening agent maleic anhydride grafted SEBS, 7.5 parts functional agent, 6 parts fiber filler glass fiber, 0.3 parts chain extender hydroquinone dihydroxyethyl ether, 0.2 parts antioxidant 1010, 1 part lubricant paraffin wax, 1.5 parts silane coupling agent 3-glycidyl etheroxypropyltriethoxysilane;

[0040] The preparation method of the PBT composite material includes the following steps:

[0041] Step 1: Weigh out each ingredient according to the specified weight proportions and set aside.

[0042] The second step is to add all the raw materials into the mixing tank, control the temperature at 110℃, the stirring speed at 800r / min, and mechanically mix for 15min to form a premix.

[0043] The third step involves adding the premixed material into a twin-screw extruder, controlling the temperatures of zone 1 to be 220℃, zone 2 to be 250℃, zone 3 to be 245℃, zone 4 to be 240℃, zone 5 to be 240℃, zone 6 to be 240℃, zone 7 to be 240℃, zone 8 to be 230℃, and zone 9 to be 220℃, while maintaining the screw speed at 100 rpm, to perform melt extrusion and obtain the composite material.

[0044] Example 3

[0045] A high-temperature resistant PBT composite material, said composite material being made from the following raw materials measured in parts by weight:

[0046] 82 parts PBT, 15 parts toughening agent maleic anhydride grafted POE, 8 parts functional agent, 12 parts fiber filler basalt fiber, 0.4 parts chain extender hydroquinone dihydroxyethyl ether, 0.3 parts antioxidant 1076, 1.5 parts lubricant stearic acid, 2 parts silane coupling agent 3-glycidyl ether oxypropyltrimethoxysilane;

[0047] The preparation method of the PBT composite material includes the following steps:

[0048] Step 1: Weigh out each ingredient according to the specified weight proportions and set aside.

[0049] The second step is to add all the raw materials into the mixing tank, control the temperature at 20℃, the stirring speed at 1000r / min, and mechanically mix for 10 minutes to form a premix.

[0050] The third step involves adding the premixed material into a twin-screw extruder, controlling the temperatures of zone 1 to be 220℃, zone 2 to be 250℃, zone 3 to be 245℃, zone 4 to be 240℃, zone 5 to be 240℃, zone 6 to be 240℃, zone 7 to be 240℃, zone 8 to be 230℃, and zone 9 to be 220℃, while maintaining the screw speed at 100 rpm, to perform melt extrusion and obtain the composite material.

[0051] The functional agents in the above embodiments were prepared using the following method:

[0052] Step 1: Add 0.5g of 3-hydroxyglutaric acid, 0.7g of 5-norbornen-2-yl(ethyl)chlorodimethylsilane and toluene to a nitrogen-filled reactor, start stirring to form a homogeneous reaction solution, then start heating and gradually increase the temperature to 65℃. Add 0.02g of triethylamine under stirring. After the addition is complete, keep the mixture warm and stir for 6 hours, then remove the solvent, stop heating, discharge the material, and purify it to obtain the norbornen derivative intermediate.

[0053] Step 2: Add 0.8g of norbornene derivative intermediate, 0.5g of N,N-di(glycidyl)aniline and N,N-dimethylformamide to the polymerization reactor, stir and mix well, and purge with nitrogen for protection. Then add 0.01g of tetrabutylammonium bromide to the polymerization reactor, turn on the heating, control the heating rate at 5℃ / min, raise the temperature to 100℃, and maintain stirring and polymerization at this temperature for 16h. Stop the reaction, cool down and discharge the material to obtain the functional agent.

[0054] Infrared analysis was performed on the functional agent. Figure 1 This is the infrared analysis test pattern of the functional agent, where 3431 cm⁻¹ -1 A characteristic absorption peak belonging to the hydroxyl group appeared at 3000-3100 cm⁻¹. -1 A hydrocarbon absorption peak belonging to the benzene ring skeleton appeared at 1779 cm⁻¹. -1 A characteristic C=O absorption peak belonging to the ester group appeared at 1748 cm⁻¹. -1 A characteristic C=O absorption peak belonging to the carboxyl group appeared at 1070 cm⁻¹. -1 Characteristic absorption peaks belonging to Si-O appeared at that location.

[0055] In step one, 3-hydroxyglutaric acid and 5-norbornen-2-yl(ethyl)chlorodimethylsilane are used as reactants. Under the action of triethylamine as an acid binder, the active hydroxyl substituents and Si-Cl groups in their structures can undergo a substitution reaction to form norbornen derivative intermediates linked by Si-O bonds.

[0056] In step two, using norbornene-derived intermediates and N,N-di(glycidyl)aniline as polymerization monomers, under the action of a phase transfer catalyst, the two equivalent carboxyl substituents in the norbornene-derived intermediate structure can undergo a continuous ring-opening esterification reaction with the two equivalent epoxy substituents in the N,N-di(glycidyl)aniline structure, to produce a macromolecular substance with an alternating norbornene-benzene ring structure linked by ester bonds, i.e., a functional agent. By controlling the ratio of the two, the functional agent can be made to exhibit carboxyl-terminated ends, where the hydroxyl groups are generated during the ring-opening esterification reaction. The presence of carboxyl and hydroxyl groups can participate in the chain extension reaction of PBT molecular chains during the melting process, thereby causing the molecular chains of the functional agent and PBT molecular chains to intertwine and crosslink, forming a three-dimensional crosslinked network structure.

[0057] Comparative Example 1

[0058] A high-temperature resistant PBT composite material, said composite material being made from the following raw materials measured in parts by weight:

[0059] 76 parts PBT, 12 parts toughening agent maleic anhydride grafted SEBS, 6 parts fiber filler glass fiber, 0.3 parts chain extender hydroquinone dihydroxyethyl ether, 0.2 parts antioxidant 1010, 1 part lubricant paraffin wax, 1.5 parts silane coupling agent 3-glycidyl etheroxypropyltriethoxysilane;

[0060] The preparation method of the PBT composite material includes the following steps:

[0061] Step 1: Weigh out each ingredient according to the specified weight proportions and set aside.

[0062] The second step is to add all the raw materials into the mixing tank, control the temperature at 110℃, the stirring speed at 800r / min, and mechanically mix for 15min to form a premix.

[0063] The third step is to add the premixed material into a twin-screw extruder, control the extrusion temperature at 260℃ and the screw speed at 100rpm, and perform melt extrusion to obtain the composite material.

[0064] Test case

[0065] The composite materials used in the examples and comparative examples were made into standard test specimens for performance testing, and the results are recorded in Table 1:

[0066] Table 1 - Performance Test Results

[0067] Example 1 Example 2 Example 3 Comparative Example 1 Tensile strength / MPa 38.1 38.6 38.5 33.9 <![CDATA[Impact strength / kJ / m 2 > 5.5 6.1 5.9 4.6 Phenomenon No phenomenon No phenomenon No phenomenon Yellowing, softening

[0068] The tensile strength test method refers to standard GB / T 1040.1-2018, and the tensile rate is set to 50 mm / min;

[0069] The test method for impact strength refers to standard GB / T 1843-2008;

[0070] The test method for high temperature resistance is as follows: the composite material is made into a test sample with a size of 2cm×2cm×1mm, placed in a constant temperature chamber at 150℃, and taken out after 72h. The specimen phenomenon is observed to evaluate the high temperature resistance.

[0071] Analysis of the test results shows that by adding functional agents, the prepared PBT composite material can exhibit excellent mechanical properties and high-temperature resistance, which is beneficial for its further application.

[0072] This document uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of these embodiments are merely to aid in understanding the method and core ideas of the present invention, including the best mode, and to enable any person skilled in the art to practice the present invention, including manufacturing and using any device or system, and implementing any combined method. It should be noted that those skilled in the art can make various improvements and modifications to the present invention without departing from its principles, and these improvements and modifications also fall within the scope of protection of the claims. The scope of protection of this patent is defined by the claims and may include other embodiments that can be conceived by those skilled in the art. If these other embodiments have structural elements similar to those expressed in the claims, or if they include equivalent structural elements that are not substantially different from those expressed in the claims, then these other embodiments should also be included within the scope of the claims.

[0073] Based on the preferred embodiments of the present invention, and through the above description, those skilled in the art can make various changes and modifications without departing from the inventive concept. The technical scope of this invention is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A method for preparing a high-temperature resistant PBT composite material, characterized in that, The composite material is made from the following raw materials measured in parts by weight: 75-82 parts PBT, 10-15 parts toughening agent, 4-8 parts functional agent, 5-12 parts fiber filler, 0.1-0.4 parts chain extender, 0.1-0.3 parts antioxidant, 0.5-1.5 parts lubricant, 1-2 parts silane coupling agent; The preparation method of the PBT composite material includes the following steps: Step 1: Weigh out each ingredient according to the specified weight proportions and set aside. The second step is to add all the raw materials into the mixing tank, control the temperature at 100-120℃, the stirring rate at 500-1000r / min, and mechanically mix for 10-20 minutes to form a premix. The third step is to add the premixed material to a twin-screw extruder for melt extrusion to obtain the composite material. The preparation method of the functional agent includes the following steps: Step 1: Add 3-hydroxyglutaric acid, 5-norbornen-2-yl(ethyl)chlorodimethylsilane and toluene to a nitrogen-filled reactor, start stirring to form a homogeneous reaction solution, then start heating and gradually increase the temperature to 60-70℃. Add an acid-binding agent while stirring. After the addition is complete, keep the mixture warm and stir for 4-6 hours, then remove the solvent, stop heating, discharge the material, and purify it to obtain the norbornen derivative intermediate. Step 2: Add norbornene derivative intermediate, N,N-di(glycidyl)aniline and N,N-dimethylformamide to the polymerization reactor, stir and mix well, purge with nitrogen, then add phase transfer catalyst to the polymerization reactor, turn on heating, control the heating rate at 3-6℃ / min, raise the temperature to 80-100℃, maintain stirring and polymerization at this temperature for 12-18h, stop the reaction, cool down and discharge the material to obtain the functional agent.

2. The method for preparing a high-temperature resistant PBT composite material according to claim 1, characterized in that, The toughening agent is maleic anhydride-grafted POE or maleic anhydride-grafted SEBS.

3. The method for preparing a high-temperature resistant PBT composite material according to claim 1, characterized in that, In step one, the molar ratio of 3-hydroxyglutaric acid and 5-norbornen-2-yl(ethyl)chlorodimethylsilane is 1:

1.

4. The method for preparing a high-temperature resistant PBT composite material according to claim 1, characterized in that, In step one, the acid-binding agent is pyridine or triethylamine.

5. The method for preparing a high-temperature resistant PBT composite material according to claim 1, characterized in that, In step two, the molar ratio of the norbornene derivative intermediate to N,N-bis(glycidyl)aniline is 1-1.2:

1.

6. The method for preparing a high-temperature resistant PBT composite material according to claim 1, characterized in that, In step two, the phase transfer catalyst is any one of tetrabutylammonium bromide, tetrabutylammonium bisulfate, tetramethylammonium bromide, or tetrabutylammonium chloride.

7. The method for preparing a high-temperature resistant PBT composite material according to claim 1, characterized in that, The fiber filler is at least one of glass fiber, basalt fiber, or illite fiber.

8. The method for preparing a high-temperature resistant PBT composite material according to claim 1, characterized in that, The chain extender is hydroquinone dihydroxyethyl ether; the antioxidant is at least one of antioxidant BHT, antioxidant 1010, or antioxidant 1076; the lubricant is at least one of polyethylene wax, paraffin wax, or stearic acid; and the silane coupling agent is 3-glycidyl etheroxypropyltrimethoxysilane or 3-glycidyl etheroxypropyltriethoxysilane.

9. A high-temperature resistant PBT composite material, characterized in that, It is prepared by the preparation method described in any one of claims 1-8.

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