Composite material, preparation method thereof and plastic shell

Abstract

The invention discloses a composite material, a preparation method of the composite material and a plastic shell, and the composite material comprises the following components in parts by mass: 30-40 parts of polyethylene glycol terephthalate; 10 to 20 parts of polyphenyl ether; 20 to 30 parts of glass fiber; 5-15 parts of a flame retardant A; 5-15 parts of a flame retardant B; the intrinsic viscosity of the polyphenyl ether is 0.35 to 0.55 dl / g; the flame retardant A is aluminum diethylphosphinate; and the flame retardant B is melamine polyphosphate. The composite material provided by the invention has good comprehensive mechanical property, flame retardant property and electrical insulation property.

Description

Technical Field

[0001] The present invention belongs to the field of engineering plastics, and in particular relates to a composite material, a preparation method thereof, and a plastic shell. Background Art

[0002] In recent years, the rapid development of my country's electronics and electrical industry, coupled with rising public awareness of environmental protection, has led to a growing demand for high-electrical-insulation, ultra-high-strength, halogen-free, flame-retardant reinforced engineering plastics. Applications such as low-voltage vacuum contactors, circuit breakers, residual current devices (RCDs), low-voltage switches, and thin-walled electronic and electrical components require engineering plastics with excellent combined mechanical, flame-retardant, and electrical-insulating properties. This is particularly true in areas where thermoset plastics have traditionally been used. Due to the complex molding process and lack of recycling, ultra-high-strength, heat-resistant alternatives are in high demand. Furthermore, with increasing awareness of safety and environmental protection, low-smoke, halogen-free flame-retardant systems are rapidly replacing halogen-containing flame-retardant systems that generate high smoke and are highly toxic. In this product segment, polyamide (PA) is the most widely used, followed by polyethylene terephthalate (PET). Because the development of flame retardants has lagged behind the industry's increasingly stringent material requirements, the addition of many flame retardants to materials can significantly reduce their mechanical and electrical-insulating properties. For example, compared with the tracking index (CTI) dropped from 600V to 200V or even lower, in addition, with the implementation of the EU RoHs and WEEE directives, the traditional brominated flame retardant system can no longer meet this requirement. Summary of the Invention

[0003] In order to solve the above technical problems, the purpose of the present invention is to provide a composite material and a preparation method thereof and a plastic shell, so that the composite material has good comprehensive mechanical properties, flame retardant properties and electrical insulation properties.

[0004] The present invention provides a composite material, which comprises the following components in parts by mass:

[0005]

[0006] The flame retardant A is aluminum diethylphosphinate; the flame retardant B is melamine polyphosphate.

[0007] The intrinsic viscosity of the polyphenylene ether is 0.35 to 0.55 dl / g, for example, 0.35 dl / g, 0.40 dl / g, 0.45 dl / g, 0.50 dl / g, and 0.55 dl / g, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0008] The composite material provided by the present invention utilizes PPO with an intrinsic viscosity of 0.35 to 0.55 dl / g and PET as a blend. The PPO can be fully melt-blended and evenly dispersed with the PET, forming stronger physical entanglements and interactions between the two, enhancing interfacial bonding. Furthermore, the PPO with an intrinsic viscosity of 0.35 to 0.55 dl / g can effectively enhance the tensile and flexural strength of the PET matrix. Furthermore, the PPO is evenly dispersed within the PET matrix, preventing the formation of conductive pathways while forming a good interface, reducing micropores and cracks and lowering the risk of leakage current. In addition, flame retardant A, aluminum diethylphosphinate, and flame retardant B, melamine polyphosphate, can also be uniformly dispersed in the blended dispersion system of PPO and PET with an intrinsic viscosity of 0.35 to 0.55 dl / g of the present invention. On the one hand, at high temperatures, the carbonization property of PPO can form a continuous carbon layer, and the uniformly dispersed flame retardant can uniformly absorb heat and decompose. The two work together to form a high-efficiency barrier layer; on the other hand, the uniform dispersion of flame retardant, PPO, and PET is not easily introduced into microscopic conductive paths, which is beneficial to improving the resistivity and improving the electrical insulation properties of the composite material.

[0009] Preferably, the intrinsic viscosity of the polyphenylene ether is 0.4 to 0.5 dl / g.

[0010] The intrinsic viscosity of the polyphenylene ether described in this solution is 0.4 to 0.5 dl / g, which can further improve the comprehensive mechanical properties, flame retardant properties and electrical insulation properties of the composite material.

[0011] Preferably, the mass ratio of the flame retardant A to the flame retardant B is (1:2) to (2:1), for example, 1:2, 1.5:2, 1:1, 1.5:1, 2:1, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0012] The mass ratio of the flame retardant A to the flame retardant B in this solution is (1:2) to (2:1), which can further improve the comprehensive mechanical properties, flame retardant properties and electrical insulation properties of the composite material.

[0013] Preferably, the glass fibers include surface-treated alkali-free chopped glass fibers.

[0014] Preferably, the composite material further comprises at least one of a toughening agent, a compatibilizer, an antioxidant, and a lubricant.

[0015] Preferably, the composite material further comprises a toughening agent, a compatibilizer, an antioxidant and a lubricant.

[0016] Preferably, by weight, it also includes:

[0017]

[0018] More preferably, the compatibilizer comprises maleic anhydride grafted polystyrene (PS-g-MAH).

[0019] The compatibilizer maleic anhydride grafted polystyrene (PS-g-MAH) in this scheme can improve the compatibility between the substrate polyethylene terephthalate and polyphenylene ether, thereby further improving the comprehensive mechanical properties, flame retardancy and electrical insulation properties of the composite material.

[0020] The present invention provides a method for preparing the composite material, which comprises the following steps:

[0021] S1. The components of the composite material are mixed uniformly;

[0022] S2. melt blending and extrusion molding by a parallel twin-screw extruder;

[0023] S3. After cooling, air-drying, pelletizing and drying, the composite material is obtained.

[0024] The preparation method of the composite material of the present invention adopts a parallel twin-screw extruder to process the composite material. On the one hand, the parallel twin-screw extruder has a strong shearing effect and a fast turning speed, which enables the material to be more fully mixed and plasticized during the extrusion process; on the other hand, the parallel twin-screw extruder adopts a multi-stage independent temperature control system, which can accurately control the temperature of each heating zone, ensuring the temperature stability of the material during the transportation, melting and homogenization processes, helping to avoid material degradation or uneven plasticization, thereby ensuring the quality of the composite material.

[0025] Preferably, the twin screw speed of the parallel twin screw extruder is 200-260 r / min

[0026] Preferably, the twin-screw speed of the parallel twin-screw extruder is 200-240 r / min.

[0027] The present invention also provides a plastic shell and the composite material. DETAILED DESCRIPTION

[0028] In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0029] Example 1

[0030] The composite material of this embodiment includes the following components in parts by mass:

[0031]

[0032] The preparation method of the composite material of this embodiment is as follows:

[0033] S1. The components of the composite material are mixed uniformly;

[0034] S2. Melt blending was performed by a parallel twin-screw extruder at a twin-screw speed of 240 r / min. The temperatures of the twin-screw extruder zones 1-10 were set to 200 ℃, 240 ℃, 270 ℃, 280 ℃, 280 ℃, 270 ℃, 260 ℃, 255 ℃, 255 ℃, and 270 ℃, and the die temperature was 280 ℃ for extrusion molding.

[0035] S3. After cooling, air-drying, pelletizing and drying, a composite material is obtained.

[0036] Example 2

[0037] The composite material of this embodiment includes the following components in parts by mass:

[0038]

[0039] The preparation method of the composite material in this embodiment is the same as that in Example 1.

[0040] Example 3

[0041] The polyphenylene ether in the composite material component of this embodiment is LXR035, purchased from Nantong Xingchen Synthetic Materials Co., Ltd., and the rest is the same as in Example 1.

[0042] The preparation method of the composite material in this embodiment is the same as that in Example 1.

[0043] Example 4

[0044] The composite material of this embodiment includes the following components in parts by mass:

[0045]

[0046]

[0047] The preparation method of the composite material in this embodiment is the same as that in Example 1.

[0048] Comparative Example 1

[0049] The polyphenylene ether in the composite material component of this embodiment was purchased from Dalian Zhongmu Chemical Co., Ltd., with the brand name ZM030 and an intrinsic viscosity of 0.3 dL / g. The rest was the same as in Example 1.

[0050] The preparation method of the composite material in this embodiment is the same as that in Example 1.

[0051] Comparative Example 2

[0052] The polyphenylene ether in the composite material component of this embodiment was purchased from Dalian Zhongmu Chemical Co., Ltd., with the brand name ZM060 and an intrinsic viscosity of 0.6 dL / g. The rest was the same as in Example 1.

[0053] The preparation method of the composite material in this embodiment is the same as that in Example 1.

[0054] Comparative Example 3

[0055] The flame retardant B in the composite material component of this embodiment is melamine cyanurate (MCA), and the rest is the same as in Example 1.

[0056] The preparation method of the composite material in this embodiment is the same as that in Example 1.

[0057] Performance Testing

[0058] (1) The glow wire ignition temperature (GWIT) test is carried out using the method of GB / T 5169.13-2006.

[0059] (2) The comparative tracking index (CTI) test was carried out using the method of GB / T4207-2012.

[0060] (3) The flammability test was carried out using the UL 94-2013 method.

[0061] (4) The tensile strength test was carried out using the method of GB / T 1040.2-2022.

[0062] (5) The bending strength test was carried out using the method of GB / T 9341-2008.

[0063] The composite materials prepared in the above examples and comparative examples were subjected to performance tests, and the test results are shown in Table 1 below:

[0064] Table 1

[0065]

[0066]

[0067] From Table 1 we can see that:

[0068] The composite materials of Examples 1 to 4 all fall within the scope of composite materials protected by the technical solution of the present invention, and exhibit good test results in performance tests of glow-wire ignition temperature (GWIT), comparative tracking index (CTI), flame retardancy, tensile strength, and flexural strength. In other words, the composite materials provided by the present invention have good flame retardancy, electrical insulation, and comprehensive mechanical properties. However, the composite materials of Comparative Examples 1 to 3 do not fall within the scope of composite materials protected by the technical solution of the present invention, and exhibit significant deterioration in at least one of the performance test results of glow-wire ignition temperature (GWIT), comparative tracking index (CTI), flame retardancy, tensile strength, and flexural strength. In other words, the composite materials of Comparative Examples 1 to 3 fail to simultaneously exhibit good flame retardancy, electrical insulation, and comprehensive mechanical properties.

[0069] Compared with the polyphenylene ether LXR045 (intrinsic viscosity 0.45 dl / g) used in the composite material of Example 1, the polyphenylene ether used in the composite material of Example 3 is LXR035 (intrinsic viscosity 0.35 dl / g), that is, the intrinsic viscosity of the polyphenylene ether used in the composite material of Example 3 is not in the further preferred range of 0.4 to 0.5 dl / g. The test results of the composite material of Example 3 in terms of glow wire ignition temperature (GWIT), comparative tracking index (CTI), tensile strength and flexural strength are worse than those of Example 1. This shows that when preparing the composite material of the present invention, using polyphenylene ether with an intrinsic viscosity of 0.4 to 0.5 dl / g can further improve the comprehensive mechanical properties, flame retardant properties and electrical insulation properties of the composite material.

[0070] Compared with the mass ratio of flame retardant A (aluminum diethylphosphinate) to flame retardant B (melamine polyphosphate) used in the composite material of Example 1 being 3:1, the mass ratio of flame retardant A (aluminum diethylphosphinate) to flame retardant B (melamine polyphosphate) used in the composite material of Example 4 is 1:3. The composite material of Example 4 showed good test results in performance tests of glow wire ignition temperature (GWIT), comparative tracking index (CTI), flame retardant grade, tensile strength and flexural strength. This indicates that the composite material of the present invention uses a mass ratio of flame retardant A to flame retardant B in the range of (3:1) to (1:3), which can improve the comprehensive mechanical properties, flame retardant properties and electrical insulation properties of the composite material.

[0071] Compared with the polyphenylene ether LXR045 (intrinsic viscosity 0.45 dl / g) used in the composite material of Example 1, the polyphenylene ether used in the composite materials of Comparative Examples 1 and 2 are ZM030 (intrinsic viscosity 0.30 dl / g) and ZM060 (intrinsic viscosity 0.60 dl / g), respectively. That is, the intrinsic viscosity of the polyphenylene ether used in the composite materials of Comparative Examples 1 and 2 is not within the range of 0.35 to 0.55 dl / g of the present invention. Compared with Example 1, the composite material of Comparative Example 1 has better comprehensive mechanical properties, flame retardant properties and electrical insulation properties. The results of the comparative example 2 composite material show significant degradation in terms of comprehensive mechanical properties and electrical insulation properties. This indicates that when blending PPO with an intrinsic viscosity of 0.35-0.55 dl / g with PET, PPO can be fully melt-blended and evenly dispersed with PET, forming stronger physical entanglements and interactions with PET, improving interfacial bonding. Furthermore, PPO with an intrinsic viscosity of 0.35-0.55 dl / g can effectively enhance the tensile and flexural strength of the PET matrix. Furthermore, the uniform dispersion of PPO in the PET matrix prevents the formation of conductive pathways while also forming a good interface, reducing micropores and cracks and lowering the risk of leakage current. In addition, flame retardant A, aluminum diethylphosphinate, and flame retardant B, melamine polyphosphate, can also be uniformly dispersed in the blended dispersion system of PPO and PET with an intrinsic viscosity of 0.35 to 0.55 dl / g of the present invention. When the composite material is at high temperature, the carbonizing property of PPO can form a continuous carbon layer, and the uniformly dispersed flame retardant can uniformly absorb heat and decompose. The two can work together to form a high-efficiency barrier layer. On the other hand, the uniform dispersion of flame retardant, PPO, and PET is not easily introduced into microscopic conductive paths, which is beneficial to improving the resistivity and the electrical insulation properties of the composite material.

[0072] Compared with the composite material of Example 1 in which the flame retardant B used is melamine polyphosphate, the composite material of Comparative Example 3 uses melamine cyanurate (MCA) as the flame retardant B, that is, the flame retardant B melamine cyanurate used in the composite material of Comparative Example 3 is not the specific melamine polyphosphate in the technical solution of the present invention. Compared with Example 1, the test results of the composite material of Comparative Example 3 in terms of glow wire ignition temperature (GWIT), comparative tracking index (CTI), flame retardancy grade, tensile strength and flexural strength are significantly deteriorated. This shows that although the flame retardants used as flame retardants in the composite materials of Example 1 and Comparative Example 3 are both melamine salts, when the flame retardant B melamine cyanurate in Comparative Example 3 is used in combination with the flame retardant A diethylphosphinate aluminum as a composite flame retardant of the composite material, the flame retardant properties, electrical insulation properties and comprehensive mechanical properties of the composite material of Comparative Example 3 are significantly deteriorated compared with Example 1.

[0073] The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents, but these modifications or replacements are all within the scope of protection of the present invention.

Claims

1. A composite material, characterized in that The composite material comprises the following components in parts by mass: The intrinsic viscosity of the polyphenylene ether is 0.35 to 0.55 dl / g; The flame retardant A is aluminum diethylphosphinate; the flame retardant B is melamine polyphosphate.

2. The composite material according to claim 1, characterized in that The intrinsic viscosity of the polyphenylene ether is 0.4 to 0.5 dl / g.

3. The composite material according to claim 1, characterized in that The mass ratio of the flame retardant A to the flame retardant B is (1:2) to (2:1).

4. The composite material according to claim 1, characterized in that The glass fibers include surface-treated alkali-free chopped glass fibers.

5. The composite material according to claim 1, characterized in that The composite material further comprises at least one of a toughening agent, a compatibilizer, an antioxidant, and a lubricant.

6. The composite material according to claim 5, characterized in that The composite material further comprises a toughening agent, a compatibilizer, an antioxidant and a lubricant.

7. The composite material according to claim 6, characterized in that Calculated by mass, it also includes:

8. A method for preparing the composite material according to any one of claims 1 to 7, characterized in that: The preparation method of the composite material comprises the following steps: S1. The components of the composite material are mixed uniformly; S2. melt blending and extrusion molding by a parallel twin-screw extruder; S3. After cooling, air-drying, pelletizing and drying, the composite material is obtained.

9. The method for preparing the composite material according to claim 8, characterized in that: The twin-screw speed of the parallel twin-screw extruder is 200-260 r / min.

10. A plastic shell, characterized in that: The plastic shell comprises the composite material according to any one of claims 1 to 7.

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