Low-noise PBT (polybutylene terephthalate) alloy material as well as preparation method and application thereof

Abstract

The invention discloses a low-noise PBT alloy material as well as a preparation method and application thereof, and relates to the technical field of engineering plastics. The PBT alloy material is prepared from the following components in parts by mass: 45 to 55 parts of polybutylene terephthalate, 5 to 15 parts of polycaprolactone, 0 to 30 parts of glass fiber, 5 to 15 parts of hollow glass beads, 2 to 5 parts of epoxy polyolefin compatilizer and 0.2 to 0.4 part of ester exchange inhibitor. The PBT / PCL alloy disclosed by the invention has relatively good damping performance and noise reduction effect. Meanwhile, interfaces between PBT and PCL molecular chains are tightly combined to form a sea-island structure with a stable structure, so that the material has low noise performance, and meanwhile, the loss of mechanical properties of the material is reduced; the material is excellent in processability, shrinkage and warping are reduced, and the dimensional stability is improved.

Description

Technical Field

[0001] This application relates to the field of engineering plastics technology, and in particular to a low-noise PBT alloy material, its preparation method, and its application. Background Technology

[0002] Polybutylene terephthalate (PBT) is a semi-crystalline engineering plastic with comprehensive performance, excellent cost, and wide applications. It possesses excellent mechanical, electrical, and dimensional properties, while also exhibiting superior heat resistance, weather resistance, and chemical resistance, making it widely used in the automotive, home appliance, and electronics industries. However, excessive noise from PBT in some transmission components and parts of home appliances, such as motor shafts, refrigerator compressors, and washing machine rotors, can significantly disrupt daily life. Therefore, developing a low-noise PBT material is essential.

[0003] Currently, there is very little research in the industry on the development of noise-reducing PBT materials. The main noise reduction solutions involve adding specific noise-reducing additives. For example, patent CN104693695A describes a lightweight noise-reducing polybutylene terephthalate (PET) material and its preparation method. This involves adding glass microspheres and glass fibers to PET, along with lubricants, antioxidants, and coupling agents. The glass microspheres improve the material's mechanical properties while maintaining its low density. The unique structure of the hollow glass microspheres also gives the material a certain degree of noise reduction. However, the large addition of hollow particles leads to a decrease in mechanical properties, and the above solution only achieves cavity damping through the addition of hollow particles, resulting in a single noise reduction mechanism and extremely limited noise reduction effect on PBT materials. Summary of the Invention

[0004] The purpose of this invention is to overcome the defects and shortcomings of existing PBT and provide a low-noise PBT alloy material that simultaneously possesses excellent mechanical properties and low-noise performance.

[0005] Another objective of this invention is to provide a method for preparing PBT alloy materials.

[0006] Another object of the present invention is to provide the application of the above-mentioned PBT alloy material in the manufacture of transmission components.

[0007] The above-mentioned objective of this invention is achieved through the following technical solution: This invention protects a PBT alloy material comprising the following components by weight: 45-55 parts of polybutylene terephthalate, 5-15 parts of polycaprolactone, 0-30 parts of glass fiber, 5-15 parts of hollow glass microspheres, 2-5 parts of epoxy-based polyolefin compatibilizer, and 0.2-0.4 parts of transesterification inhibitor.

[0008] This invention utilizes a specific ratio of polybutylene terephthalate (PET) and polycaprolactone (PCL) to prepare a PBT / PCL alloy. The excellent flexibility of the PCL molecular chain helps reduce friction caused by slippage between molecular chains during vibration, resulting in superior damping performance and noise reduction in the PBT / PCL alloy system. Simultaneously, the epoxy groups in the compatibilizer react with the hydroxyl and carboxyl groups at the ends of the PBT and PCL molecular chains, strengthening the interfacial bond between PBT and PCL and forming a stable sea-island structure. This allows the PBT / PCL alloy system to exhibit low noise performance while minimizing the loss of mechanical properties. Furthermore, the addition of a specific amount of transesterification inhibitor reduces disordered transesterification reactions between the PBT and PCL molecular chains, minimizing interfacial disruption and maintaining the stability of the two-phase structure, thereby improving the material's mechanical properties and thermal stability. Furthermore, the introduction of low-density hollow glass microspheres creates a uniformly distributed closed-cell structure within the matrix, and the interface between them has a large acoustic impedance difference, which can reduce the propagation speed and intensity of sound waves. Through the synergy of a specific PBT / PCL system and hollow glass microspheres, a multi-level noise reduction mechanism is formed, which effectively increases the low-noise performance without significantly damaging the mechanical properties of the material. The low-noise stability and durability are high.

[0009] Furthermore, the present invention can incorporate a certain amount of glass fiber according to mechanical performance requirements, thereby improving mechanical performance while maintaining low noise performance.

[0010] In some embodiments, the content of polybutylene terephthalate that can achieve the purpose of the present invention can be any range between 45 parts, 46 parts, 47 parts, 48 ​​parts, 49 parts, 50 parts, 51 parts, 52 parts, 53 parts, 54 parts, 55 parts or more of the component content.

[0011] In some embodiments, the polycaprolactone content that can achieve the purpose of the present invention can be any range between 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, 10 parts, 11 parts, 12 parts, 13 parts, 14 parts, 15 parts or more of the component content.

[0012] In some embodiments, the content of hollow glass microspheres that can achieve the purpose of the present invention can be any range between 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, 10 parts, 11 parts, 12 parts, 13 parts, 14 parts, 15 parts or more of the component content.

[0013] In some embodiments, the content of the epoxy-based polyolefin compatibilizer that can achieve the purpose of the present invention can be any range between 2 parts, 2.5 parts, 3 parts, 3.5 parts, 4 parts, 4.5 parts, 5 parts or more of the component content.

[0014] In some embodiments, the mass ratio of polybutylene terephthalate (PBT) to polycaprolactone (PCL) is (3-8):1. By blending specific amounts of PBT and PCL, the overall heat resistance of the material is improved, resulting in better low-noise performance.

[0015] Optionally, the mass ratio of polybutylene terephthalate to polycaprolactone is any one of 3:1, 3.5:1, 4:1, 4.5:1, 5:1, 5.5:1, 6:1, 6.5:1, 7:1, 7.5:1, and 8:1.

[0016] In some embodiments, the intrinsic viscosity of the polybutylene terephthalate is 0.70-1.2 dL / g; the intrinsic viscosity test standard is ISO1628-5-2015, preferably, the intrinsic viscosity is 0.70-0.85 dL / g.

[0017] In some embodiments, the polycaprolactone has a melt index of 4-50 g / 10 min at 160°C and 2.16 kg; the melt index is tested according to ISO 1133-2022, and preferably, the melt index is 12-20 g / 10 min.

[0018] In some embodiments, the epoxy-based polyolefin compatibilizer is selected from at least one of ethylene octene copolymer grafted glycidyl methacrylate (POE-g-GMA) and ethylene methyl acrylate-glycidyl methacrylate block copolymer, wherein the mass content of glycidyl methacrylate in the epoxy-based polyolefin compatibilizer is 2%-6%.

[0019] In some embodiments, the hollow glass microspheres have a D90 particle size of 5-30 μm; preferably, the D90 particle size is 8-12 μm.

[0020] In some embodiments, the glass fiber has a diameter of 7-15 μm and a length of 3-5 mm.

[0021] In some embodiments, the transesterification inhibitor is selected from at least one of disodium dihydrogen pyrophosphate, sodium dihydrogen phosphate, or zinc dihydrogen phosphate.

[0022] The PBT alloy material of the present invention may be supplemented with commonly used additives in the art, including but not limited to at least one of lubricants and antioxidants.

[0023] In some embodiments, the mixture also includes 0.3-1 parts of lubricant and 0.1-0.3 parts of antioxidant.

[0024] The types of lubricants and antioxidants in this invention are not particularly limited; optionally, the lubricant includes at least one of ester lubricants, amide lubricants, polyethylene lubricants, or stearic acid lubricants. Preferably, the lubricant is an ester lubricant; specifically, it is at least one of lower alcohol esters, higher alcohol esters, polyol esters, or polyethylene glycol esters of fatty acids.

[0025] Optionally, the antioxidant includes at least one of hindered phenolic antioxidants, amine antioxidants, hydroxylamine antioxidants, or benzofuranone antioxidants, or a combination thereof with an auxiliary antioxidant; preferably, it is a hindered phenolic antioxidant, specifically, the hindered phenolic antioxidant may be selected from antioxidant 1010, antioxidant 1076, or antioxidant 264.

[0026] The auxiliary antioxidant includes phosphite antioxidants or thioester antioxidants. Specifically, the auxiliary antioxidant can be selected from antioxidant 168, antioxidant 626, antioxidant DLTDP, or antioxidant DSTDP.

[0027] This invention protects a method for preparing a PBT alloy material, comprising the following steps: mixing the raw materials of each component evenly, melting and extruding, granulating, to obtain the PBT alloy material.

[0028] Preferably, the method for preparing the PBT alloy material includes the following steps: 1) Mix PBT resin, PCL resin, compatibilizer, lubricant, transesterification inhibitor and antioxidant evenly; 2) The mixture obtained in step 1), along with glass fiber and hollow glass microspheres, are fed into a twin-screw extruder for mixing, melt extrusion, and granulation to obtain the PBT alloy material.

[0029] Preferably, the preparation method of the PBT alloy material employs a twin-screw extruder for melt extrusion processing. The temperature of the twin-screw extruder from the feed port to the die head is 200-230℃ in zone 1, 220-240℃ in zone 2, 225-245℃ in zone 3, 225-245℃ in zone 4, 225-245℃ in zone 5, 230-250℃ in zone 6, 230-250℃ in zone 7, 220-240℃ in zone 8, 220-240℃ in zone 9, and 230-250℃ in zone 10. The screw speed of the twin-screw extruder is 200-450 rpm.

[0030] This invention protects the application of a PBT alloy material in the manufacture of transmission components.

[0031] Optionally, the transmission components include, but are not limited to, the motor shaft, the refrigerator compressor components, and the stator and rotor of the washing machine.

[0032] Compared with the prior art, the beneficial effects of the present invention are: This invention provides a PBT alloy material. The PCL molecular chains in the PBT / PCL alloy exhibit excellent flexibility, which helps reduce friction caused by slippage between molecular chains during vibration, resulting in better damping performance and noise reduction. Simultaneously, the epoxy groups in the compatibilizer react with the hydroxyl and carboxyl groups at the ends of the PBT and PCL molecular chains, making the interface between the PBT and PCL molecular chains more tightly bonded, forming a stable sea-island structure. This allows the material to have low noise performance while minimizing the loss of its mechanical properties. Furthermore, the introduction of low-density hollow glass microspheres creates a uniformly distributed closed-cell structure within the matrix, and the interface has a large acoustic impedance difference, which can reduce the propagation speed and intensity of sound waves. Through the synergistic effect of the specific PBT / PCL system and hollow glass microspheres, a multi-layered noise reduction mechanism is formed, effectively increasing low noise performance without significantly damaging the material's mechanical properties, thus improving the stability and durability of the low noise performance. Detailed Implementation

[0033] The present invention will be further described below with reference to specific embodiments, but the embodiments do not limit the present invention in any way. Unless otherwise stated, the raw materials and reagents used in the embodiments of the present invention are conventionally purchased raw materials and reagents.

[0034] The raw materials for the examples and comparative examples are as follows: PBT resin: PBT-1: Intrinsic viscosity 0.83 dL / g, intrinsic viscosity test standard is ISO1628-5-2015; Changchun Chemical (Jiangsu) Co., Ltd., PBT 1200-211M.

[0035] PBT-2: Intrinsic viscosity 0.73 dL / g, intrinsic viscosity test standard is ISO1628-5-2015; Jiangsu Yizheng Chemical Fiber Co., Ltd., PBT GX111.

[0036] PCL resin: PCL-1: Melt flow index 17 g / 10min, its test standard is ISO 1133-2022, test conditions 160℃ / 2.16kg; Shenzhen Guanghua Weiye Co., Ltd., eSUN600C.

[0037] PCL-2: Melt flow index 42 g / 10min, its test standard is ISO 1133-2022, test conditions 160℃ / 2.16kg; Shenzhen Guanghua Weiye Co., Ltd., eSUN500C.

[0038] PCL-3: Melt flow index 6 g / 10 min, its test standard is ISO 1133-2022, test conditions 160℃ / 2.16 kg; Shenzhen Guanghua Weiye Co., Ltd., eSUN800C.

[0039] Hollow glass microspheres: Hollow glass microspheres-1: D90 particle size is 10μm; Zhengzhou Shenglait New Material Co., Ltd., HM10.

[0040] Hollow glass microspheres-2: D90 particle size is 15μm; Zhengzhou Shenglait New Material Co., Ltd., HM15.

[0041] Hollow glass microspheres-3: D90 particle size is 30μm; Zhengzhou Shenglait New Material Co., Ltd., HM30.

[0042] The D90 particle size was measured using a laser particle size analyzer according to the method in GB / T 19077-2008.

[0043] Fiberglass: Taishan Fiberglass Co., Ltd., HMG436S-10-4.0.

[0044] Compatibilizer-1: POE-g-GMA graft copolymer; Jia Yi Rong SOG-03.

[0045] Compatibilizer-2: POE-g-MAH graft copolymer, Shenyang Ketong KT-915.

[0046] Lubricant: Silicone lubricant; GT-300, commercially available.

[0047] Antioxidant: RIANOX 1076, commercially available.

[0048] Ester exchange inhibitor-1: Sodium dihydrogen pyrophosphate, Nagase (Hong Kong) Limited.

[0049] Ester exchange inhibitor-2: Sodium dihydrogen phosphate, Lianyungang Xidu Biochemical Co., Ltd.

[0050] The preparation methods of the PBT alloy materials in the following examples and comparative examples include the following steps: 1) Place all raw material components except glass fiber and hollow glass microspheres into a high-speed mixer and dry mix for 3 minutes at a speed of 700 rpm; 2) The mixture obtained in step 1), glass fiber and hollow glass microspheres are fed into a twin-screw extruder through a feeder for mixing, dispersing, melt extrusion and granulation. The glass fiber and hollow glass microspheres are fed through a side feeding method.

[0051] The twin-screw extruder has the following temperature zones from the feed inlet to the die head: Zone 1: 215℃; Zone 2: 230℃; Zone 3: 235℃; Zone 4: 235℃; Zone 5: 235℃; Zone 6: 240℃; Zone 7: 240℃; Zone 8: 230℃; Zone 9: 230℃; Zone 10: 240℃. The screw speed of the twin-screw extruder is 350 rpm.

[0052] Examples 1-13 This embodiment provides a series of PBT alloy materials, the composition of which by mass is shown in Table 1.

[0053] Table 1

[0054] Comparative Examples 1-5 This comparative example provides a series of PBT alloy materials, the composition of which by mass parts is shown in Table 2.

[0055] Table 2

[0056] Performance testing The PBT alloy materials of the above embodiments and comparative examples were subjected to the following performance tests, and the results are shown in Table 3.

[0057] 1. Noise Assessment: Based on industry standard VDA230 proposed by the German Association of the Automotive Industry (VDA). 206 Risk Factor for Abnormal Noise (RPN) Testing in 2005. Test conditions: The contact area between the test sample and the friction pair is 1250 mm². 2 The sliding distance is fixed at 50mm, the sliding speed is 4mm / s, and the load is 10N. Before the test, the sample is conditioned in an environment with a temperature of (23±2)℃ and a relative humidity of (50±5)% for more than 24 hours.

[0058] RPN is the product of the frequency, severity, and detection level of an event, and is known as the risk factor or risk order number. The higher the value, the more serious the potential problem. In noise assessment tests, when RPN ≤ 3, the material has a low risk of abnormal noise and exhibits low-noise performance; when 3 < RPN ≤ 6, the material has a moderate risk of abnormal noise; and when RPN > 6, the material has a high risk of abnormal noise.

[0059] 2. Noise assessment after aging: The sample was baked in an 80℃ oven for 1000 hours, and the RPN coefficient of the test material was taken out after aging.

[0060] Table 3

[0061] As shown in Table 3, the PBT alloy material of this invention has the characteristics of excellent low noise performance and good aging resistance. Its noise assessment RPN coefficient is ≤2, and the noise assessment RPN coefficient after aging at 80℃ for 1000h is ≤3.

[0062] In addition, the PBT alloy materials of Examples 1 and 12 were subjected to tensile strength (ISO 527-2025) and notched impact strength (ISO 180-2019) tests, respectively. The results showed that the tensile strength of the PBT alloy material of Example 12 was 58 MPa and the notched impact strength was 5.6 kJ / m. 2 Its mechanical properties meet the needs of most application scenarios and it has excellent low-noise performance. Example 1 shows that adding a specific amount of glass fiber further enhances its mechanical properties, achieving a tensile strength of 124 MPa and a notched impact strength of 12.6 kJ / m. 2 At the same time, it will not cause a significant decrease in low-noise performance.

[0063] Compared to Example 1, Comparative Examples 1-3, which do not contain PCL and / or hollow glass microspheres, have an RPN coefficient ≥4 in their noise assessments, indicating poor low-noise performance. In Comparative Example 4, excessive PCL content reduces the tensile strength and notched impact strength of the material, and also results in poor low-noise performance.

[0064] The compatibilizer in Comparative Example 5 is a POE-g-MAH graft copolymer, which does not contain crosslinking groups such as epoxy groups. This affects the tight interfacial bonding between PBT and PCL molecular chains, resulting in a decrease in the tensile strength and notched impact strength of the material, and also reduces the low-noise performance to some extent.

[0065] The above embodiments of the present invention are merely examples for clearly illustrating the present invention and are not intended to limit the implementation of the present invention. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively describe all possible implementations here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A PBT alloy material, characterized in that, Includes the following components by mass: 45-55 parts of polybutylene terephthalate, 5-15 parts of polycaprolactone, 0-30 parts of glass fiber, 5-15 parts of hollow glass microspheres, 2-5 parts of epoxy-based polyolefin compatibilizer, and 0.2-0.4 parts of transesterification inhibitor.

2. The PBT alloy material according to claim 1, characterized in that, The mass ratio of polybutylene terephthalate to polycaprolactone is (3-8):

1.

3. The PBT alloy material according to claim 1, characterized in that, The intrinsic viscosity of the polybutylene terephthalate is 0.70-1.2 dL / g; preferably, the intrinsic viscosity is 0.70-0.85 dL / g.

4. The PBT alloy material according to claim 1, characterized in that, The polycaprolactone has a melt index of 4-50 g / 10 min at 160 °C and 2.16 kg; preferably, the melt index is 12-20 g / 10 min.

5. The PBT alloy material according to claim 1, characterized in that, The epoxy-based polyolefin compatibilizer is selected from at least one of ethylene octene copolymer grafted glycidyl methacrylate and ethylene methyl acrylate-glycidyl methacrylate block copolymer.

6. The PBT alloy material according to claim 1, characterized in that, The hollow glass microspheres have a D90 particle size of 5-30 μm; preferably, the D90 particle size is 8-12 μm.

7. The PBT alloy material according to claim 1, characterized in that, The glass fiber has a diameter of 7-15 μm.

8. The PBT alloy material according to any one of claims 1-7, characterized in that, Also includes: Lubricant 0.3-1 part, antioxidant 0.1-0.3 part.

9. A method for preparing the PBT alloy material according to any one of claims 1-8, characterized in that, The process includes the following steps: mixing the raw materials of each component evenly, melting and extruding, and granulating to obtain the PBT alloy material.

10. The application of the PBT alloy material according to any one of claims 1-8 in the manufacture of transmission components.

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