Anti-warping reinforced PBT (polybutylene terephthalate) material and preparation method thereof

Abstract

The invention belongs to the technical field of PBT (polybutylene terephthalate) materials, and particularly relates to an anti-warping reinforced PBT material and a preparation method of the anti-warping reinforced PBT material. 5 to 10 parts of nano silicon dioxide; 8 to 12 parts of glass fiber; 3 to 7 parts of carbon nano tube; 0.5 to 1.5 parts of an antioxidant 1010; 1-2 parts of a lubricant calcium stearate; 2-4 parts of a toughening agent ethylene-methyl acrylate copolymer; 1-3 parts of a compatilizer maleic anhydride grafted polypropylene; and 2-5 parts of conductive filler silver powder. By optimizing the proportion of all the components and the preparation process, the good dispersity of the nano filler and the ideal interface interaction between the nano filler and a PBT matrix are ensured; therefore, the warping resistance of the material is remarkably improved, the excellent dielectric property of the material is also ensured, and a new solution is provided for the application of the PBT material.

Description

Technical Field

[0001] The invention belongs to the technical field of PBT materials, and particularly relates to an anti-warping reinforced PBT material and a preparation method thereof. Background Art

[0002] Polybutylene terephthalate (PBT), a high-performance engineering plastic, is widely used in the electronics, electrical, and automotive industries due to its excellent mechanical properties, chemical resistance, and thermal stability. However, traditional PBT is prone to warping during the molding process, primarily due to uneven shrinkage during cooling. Furthermore, as application requirements for material performance increase, enhancing PBT's warpage resistance while maintaining or improving its dielectric properties has become a pressing issue.

[0003] In existing technologies, glass fibers or other fillers are often added to improve the mechanical properties and dimensional stability of PBT materials. However, these methods often struggle to precisely control the dispersion of the nanofillers and their interfacial interactions with the PBT matrix, which can affect the overall performance of the material. For example, improper filler dispersion can lead to localized stress concentrations, exacerbating warping and potentially compromising the material's dielectric properties. Summary of the Invention

[0004] The purpose of the present invention is to provide a warpage-resistant reinforced PBT material and a preparation method thereof, which not only significantly improves the warpage resistance of the material but also ensures its excellent dielectric properties, so as to solve the problems raised in the above background technology.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: a warping-resistant reinforced PBT material, which is composed of 40-60 parts of polybutylene terephthalate; 5-10 parts of nano-silicon dioxide; 8-12 parts of glass fiber; 3-7 parts of carbon nanotubes; 0.5-1.5 parts of antioxidant 1010; 1-2 parts of lubricant calcium stearate; 2-4 parts of toughening agent ethylene-methyl acrylate copolymer; 1-3 parts of compatibilizer maleic anhydride grafted polypropylene; and 2-5 parts of conductive filler silver powder.

[0006] Preferably, the nano-silica is hydrophobic nano-silica.

[0007] Preferably, the glass fiber has a length of 3-5 mm and a diameter of 10-15 μm.

[0008] Preferably, the carbon nanotubes have a diameter of 10-20 nm and a length of 5-15 μm.

[0009] Preferably, the grafting rate of the compatibilizer maleic anhydride grafted onto polypropylene is 0.8%-1.2%.

[0010] On the other hand, the present invention provides a method for preparing a warpage-resistant reinforced PBT material, comprising the following steps:

[0011] Weighing polybutylene terephthalate, nano-silica, glass fiber, and carbon nanotubes according to their weights and mixing them evenly to obtain a mixture A;

[0012] Antioxidant 1010 and lubricant calcium stearate were added to a high-speed mixer for premixing to obtain a mixture B;

[0013] Mixtures A and B are melt-blended through a twin-screw extruder, and the temperature of the twin-screw extruder is controlled between 230°C and 260°C;

[0014] During the melt blending process, toughening agent ethylene-methyl acrylate copolymer and compatibilizer maleic anhydride grafted polypropylene are gradually added, and conductive filler silver powder is incorporated during the extrusion process;

[0015] The extruded material is cooled and cut into pellets of the desired size to complete the production process.

[0016] Preferably, the screw speed of the twin-screw extruder is 200-300 rpm.

[0017] Preferably, the temperature for adding the toughening agent ethylene-methyl acrylate copolymer is 240°C to 250°C.

[0018] Preferably, the particle size of the conductive filler silver powder is 1 μm to 5 μm.

[0019] Preferably, the cooling is carried out by air cooling, and the cooling time is 10 minutes to 15 minutes.

[0020] Technical effects and advantages of the present invention: The anti-warping reinforced PBT material and its preparation method proposed in the present invention have the following advantages over the prior art:

[0021] The anti-warpage reinforced PBT material proposed in the present invention not only contains appropriate amounts of reinforcing ingredients such as glass fiber and carbon nanotubes, but also adds maleic anhydride grafted polypropylene as a compatibilizer, ethylene-methyl acrylate copolymer as a toughening agent, and conductive filler silver powder. By optimizing the proportions of each component and the preparation process, the good dispersion of the nanofiller and its ideal interfacial interaction with the PBT matrix are ensured. This not only significantly improves the material's anti-warpage performance, but also ensures its excellent dielectric properties, providing a new solution for the application of PBT materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 The present invention is a flow chart of a method for preparing a warpage-resistant reinforced PBT material. DETAILED DESCRIPTION

[0023] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. The specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0024] Example 1

[0025] The present invention provides a warpage-resistant reinforced PBT material, which comprises the following materials by weight:

[0026] Polybutylene terephthalate (PBT): 40 parts;

[0027] Hydrophobic nano-silica: 5 parts;

[0028] Glass fiber (length 3 mm, diameter 10 μm): 8 parts;

[0029] Carbon nanotubes (diameter 10 nm, length 5 μm): 3 parts;

[0030] Antioxidant 1010: 0.5 parts;

[0031] Lubricant calcium stearate: 1 part;

[0032] Toughening agent ethylene-methyl acrylate copolymer (EMA): 2 parts;

[0033] Compatibilizer maleic anhydride grafted polypropylene (PP-g-MAH), grafting rate 0.8%: 1 part;

[0034] Conductive filler silver powder (particle size 1 μm): 2 parts.

[0035] In a preferred embodiment, the nano-silica is hydrophobic. This facilitates its uniform dispersion within the PBT matrix. Furthermore, the compatibilizer PP-g-MAH has a grafting rate of 0.8% to ensure it effectively improves the interfacial bonding between the PBT matrix and other components. This type of nano-silica exhibits improved dispersibility and stability, effectively preventing agglomeration and improving the overall performance of the material.

[0036] In a preferred embodiment, the grafting rate of the compatibilizer maleic anhydride grafted onto polypropylene is 0.8%. The specific grafting rate is selected to ensure that it can effectively improve the interfacial bonding between the PBT matrix and other components, thereby enhancing the mechanical properties and anti-warpage performance of the material.

[0037] The preparation method of the above-mentioned anti-warping reinforced PBT material is as follows: Figure 1 As shown, the following steps are included:

[0038] Weighing polybutylene terephthalate, nano-silica, glass fiber, and carbon nanotubes according to their weights and mixing them evenly to obtain a mixture A;

[0039] Antioxidant 1010 and lubricant calcium stearate were added to a high-speed mixer for premixing to obtain a mixture B;

[0040] Mixtures A and B were melt blended by a twin-screw extruder (screw speed was 200), and the temperature of the twin-screw extruder was controlled between 230°C;

[0041] During the melt blending process, the toughening agent ethylene-methyl acrylate copolymer and the compatibilizer maleic anhydride grafted polypropylene are gradually added, and the conductive filler silver powder (particle size of 1μm) is incorporated during the extrusion process; silver powder, as a high-efficiency conductive filler, can significantly improve the conductivity and dielectric properties of the material without affecting other properties of the material, and is suitable for application scenarios requiring high-precision electronic components.

[0042] In a preferred embodiment, the addition temperature of the toughening agent ethylene-methyl acrylate copolymer is 240°C.

[0043] The extruded material is cooled and cut into particles of a desired size to complete the preparation process. In a preferred embodiment, the cooling is performed by air cooling for 10 minutes.

[0044] Thanks to the precise control of the nanofiller's dispersion and its interfacial interaction with the PBT matrix, the material exhibits significantly reduced warping during the molding process. The introduction of glass fiber and carbon nanotubes significantly enhances the material's mechanical strength and toughness, making it more durable. The addition of conductive silver filler not only does not compromise the material's dielectric properties, but actually helps adjust its conductivity and dielectric constant, broadening its application range. The use of antioxidants and lubricants improves the material's thermal stability and processing fluidity, facilitating subsequent molding processes.

[0045] In summary, the anti-warping reinforced PBT material and its preparation method provided by the present invention can effectively overcome the warping problem existing in traditional PBT materials, while maintaining or improving their mechanical properties and dielectric properties, showing broad application prospects.

[0046] Example 2

[0047] The invention provides an anti-warping reinforced PBT material, characterized in that the anti-warping reinforced PBT material consists of 50 parts of polybutylene terephthalate; 7 parts of nano-silicon dioxide; 15 parts of glass fiber (length 4 mm, diameter 12 μm); 5 parts of carbon nanotubes (diameter 15 nm, length 15 μm); 1 part of antioxidant 1010; 1 part of lubricant calcium stearate; 3 parts of toughening agent ethylene-methyl acrylate copolymer; 2 parts of compatibilizer maleic anhydride grafted polypropylene; and 4 parts of conductive filler silver powder.

[0048] In a preferred embodiment, the nano-silica is hydrophobic nano-silica.

[0049] In a preferred embodiment, the grafting rate of the compatibilizer maleic anhydride grafted onto polypropylene is 1%.

[0050] The preparation method of the above-mentioned anti-warping reinforced PBT material is as follows: Figure 1 As shown, the following steps are included:

[0051] Weighing polybutylene terephthalate, nano-silica, glass fiber, and carbon nanotubes according to their weights and mixing them evenly to obtain a mixture A;

[0052] Antioxidant 1010 and lubricant calcium stearate were added to a high-speed mixer for premixing to obtain a mixture B;

[0053] Mixtures A and B were melt blended by a twin-screw extruder (screw speed was 250 rpm), and the temperature of the twin-screw extruder was controlled between 240 °C;

[0054] During the melt blending process, the toughening agent ethylene-methyl acrylate copolymer and the compatibilizer maleic anhydride grafted polypropylene are gradually added, and the conductive filler silver powder (particle size is 3 μm) is incorporated during the extrusion process; in a preferred embodiment, the toughening agent ethylene-methyl acrylate copolymer is added at a temperature of 24°C.

[0055] The extruded material is cooled and cut into particles of a desired size to complete the preparation process. In a preferred embodiment, the cooling is performed by air cooling for 13 minutes.

[0056] Example 3

[0057] The invention provides an anti-warping reinforced PBT material, characterized in that the anti-warping reinforced PBT material consists of 60 parts of polybutylene terephthalate; 10 parts of nano-silicon dioxide; 12 parts of glass fiber (length 5 mm, diameter 15 μm); 7 parts of carbon nanotube (diameter 20 nm, length 15 μm); 1.5 parts of antioxidant 1010; 2 parts of lubricant calcium stearate; 4 parts of toughening agent ethylene-methyl acrylate copolymer; 3 parts of compatibilizer maleic anhydride grafted polypropylene; and 5 parts of conductive filler silver powder.

[0058] In a preferred embodiment, the nano-silica is hydrophobic nano-silica.

[0059] In a preferred embodiment, the grafting rate of the compatibilizer maleic anhydride grafted onto polypropylene is 1.2%.

[0060] The preparation method of the above-mentioned anti-warping reinforced PBT material is as follows: Figure 1 As shown, the following steps are included:

[0061] Weighing polybutylene terephthalate, nano-silica, glass fiber, and carbon nanotubes according to their weights and mixing them evenly to obtain a mixture A;

[0062] Antioxidant 1010 and lubricant calcium stearate were added to a high-speed mixer for premixing to obtain a mixture B;

[0063] Mixtures A and B were melt blended by a twin-screw extruder (screw speed was 300 rpm), and the temperature of the twin-screw extruder was controlled between 260°C;

[0064] During the melt blending process, the toughening agent ethylene-methyl acrylate copolymer and the compatibilizer maleic anhydride grafted polypropylene are gradually added, and the conductive filler silver powder (particle size of 5 μm) is incorporated during the extrusion process; in a preferred embodiment, the toughening agent ethylene-methyl acrylate copolymer is added at a temperature of 250°C.

[0065] The extruded material is cooled and cut into particles of a desired size to complete the preparation process. In a preferred embodiment, the cooling is performed by air cooling for 15 minutes.

[0066] When implementing Examples 1-3, the contents of each component are as follows:

[0067]

[0068]

[0069] The anti-warpage reinforced PBT material and its preparation method proposed in this invention effectively alleviate the warpage problem of traditional PBT materials at various formulation ratios while maintaining or improving their mechanical and dielectric properties. By precisely controlling the dispersion of the nanofiller and its interfacial interaction with the PBT matrix, the material exhibits excellent overall performance during the molding process. These improvements not only expand the application range of PBT materials but also provide new solutions for the development of high-performance engineering plastics.

[0070] To better demonstrate the superiority of the warpage-resistant, reinforced PBT material provided in Example 1, a comparative example is provided. This comparative example utilizes the same ingredients as Example 1, but removes or modifies certain key components and optimized process parameters to observe their effects on the final material's properties.

[0071] Comparative Example 1 Material Composition:

[0072] Polybutylene terephthalate (PBT): 40 parts;

[0073] Nano silicon dioxide: 5 parts;

[0074] Glass fiber (length 3 mm, diameter 10 μm): 8 parts;

[0075] Carbon nanotubes (diameter 10 nm, length 5 μm): 3 parts;

[0076] Antioxidant 1010: 0.5 parts;

[0077] Lubricant calcium stearate: 1 part;

[0078] Toughening agent ethylene-methyl acrylate copolymer (EMA): 2 parts;

[0079] Maleic anhydride grafted polypropylene (PP-g-MAH) without adding compatibilizer;

[0080] Conductive filler silver powder: 2 parts.

[0081] Preparation method steps:

[0082] PBT, nano-silica, glass fiber and carbon nanotubes were weighed according to the above proportions and mixed evenly in a high-speed blender to form a mixture A.

[0083] In another high-speed mixer, antioxidant 1010 and lubricant calcium stearate were pre-mixed to ensure uniform distribution to form mixture B.

[0084] Mixtures A and B were melt blended by a twin-screw extruder with the temperature controlled at 230° C. and the screw speed at 200 rpm.

[0085] EMA was gradually added during the melt blending process, and conductive filler silver powder (particle size of 1 μm) was incorporated during the extrusion process. Since PP-g-MAH was not added, the interfacial bonding force was weak.

[0086] The extruded material is cooled by air cooling for 10 minutes and then cut into particles of the desired size to complete the entire preparation process.

[0087] Comparison of experimental data:

[0088] Test items Example 1 Comparative Example 1 Warpage resistance Significant improvement There is obvious warping Mechanical strength (tensile strength MPa) 120 95 Elongation at break (%) 6 4 Dielectric constant (@1MHz) 3.5 3.2 Surface resistivity (Ω / sq) 1E+6 1E+7

[0089] From the experimental data we can see that:

[0090] Warpage resistance: Example 1 exhibits significantly improved warpage resistance, while Comparative Example 1 exhibits significant warpage. This indicates that the compatibilizer PP-g-MAH plays an important role in improving the material's warpage resistance.

[0091] Mechanical strength: The tensile strength of Example 1 is 120 MPa, while that of Comparative Example 1 is only 95 MPa. This indicates that PP-g-MAH helps to enhance the interfacial bonding between the matrix and other components, thereby improving the overall mechanical strength.

[0092] Elongation at break: The elongation at break of Example 1 is 6%, which is higher than 4% of Comparative Example 1. This indicates that the toughness of the material is improved after adding PP-g-MAH.

[0093] Dielectric properties: Although the dielectric constants of the two samples are not much different, the surface resistivity of Example 1 is lower, indicating that it has better conductivity and the ability to adjust the dielectric constant.

[0094] In summary, by comparing Comparative Example 1 with Example 1, it can be clearly seen that adding an appropriate amount of compatibilizer PP-g-MAH and other optimization measures to the PBT composite material can significantly improve the comprehensive performance of the material, especially the anti-warping performance and mechanical strength, further verifying the effectiveness and innovation of the present invention.

[0095] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A warpage-resistant reinforced PBT material, characterized in that: The anti-warping reinforced PBT material is composed of 40-60 parts of polybutylene terephthalate, 5-10 parts of nano-silicon dioxide, and 8-12 parts of glass fiber. Carbon nanotubes: 3-7 parts; antioxidant 1010: 0.5-1.5 parts; lubricant calcium stearate: 1-2 parts; toughening agent ethylene-methyl acrylate copolymer: 2-4 parts; compatibilizer maleic anhydride grafted polypropylene: 1-3 parts; conductive filler silver powder: 2-5 parts.

2. The anti-warping reinforced PBT material according to claim 1, characterized in that: The nano-silica is hydrophobic nano-silica.

3. The anti-warping reinforced PBT material according to claim 1, characterized in that: The glass fiber has a length of 3-5 mm and a diameter of 10-15 μm.

4. The anti-warping reinforced PBT material according to claim 1, characterized in that: The carbon nanotubes have a diameter of 10-20 nm and a length of 5-15 μm.

5. The anti-warping reinforced PBT material according to claim 1, characterized in that: The grafting rate of the compatibilizer maleic anhydride grafted onto polypropylene is 0.8%-1.2%.

6. A method for preparing the anti-warpage reinforced PBT material according to any one of claims 1 to 5, characterized in that: The steps include: Weighing polybutylene terephthalate, nano-silica, glass fiber, and carbon nanotubes according to their weights and mixing them evenly to obtain a mixture A; Antioxidant 1010 and lubricant calcium stearate were added to a high-speed mixer for premixing to obtain a mixture B; Mixtures A and B are melt-blended through a twin-screw extruder, and the temperature of the twin-screw extruder is controlled between 230°C and 260°C; During the melt blending process, toughening agent ethylene-methyl acrylate copolymer and compatibilizer maleic anhydride grafted polypropylene are gradually added, and conductive filler silver powder is incorporated during the extrusion process; The extruded material is cooled and cut into pellets of the desired size to complete the production process.

7. The method according to claim 6, characterized in that: The screw speed of the twin-screw extruder is 200-300 rpm.

8. The method according to claim 6, wherein: The temperature for adding the toughening agent ethylene-methyl acrylate copolymer is 240°C to 250°C.

9. The method according to claim 6, wherein: The particle size of the conductive filler silver powder is 1 μm to 5 μm.

10. The method according to claim 6, wherein: The cooling is carried out by air cooling, and the cooling time is 10 minutes to 15 minutes.

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