Modified engineering plastic and method for preparing the same

Abstract

The application relates to the technical field of engineering plastics, in particular to a modified engineering plastic and a preparation method thereof. According to the weight parts, the raw materials comprise the following components: 55-72 parts of polycarbonate resin, 5-12 parts of a weather-resistant synergist, 4-8 parts of a toughening compatilizer, 1-3 parts of an antioxidant, 0.5-2 parts of a lubricant, and 2-5 parts of a corrosion-resistant filler; the preparation raw materials of the weather-resistant synergist comprise talcum powder, 2-(2-hydroxy-5-methylphenyl) benzotriazole, N,N-bis(2,2,6,6-tetramethyl-4-piperidyl) ethylenediamine and maleic anhydride grafted paraffin. In the modified engineering plastic, the weather-resistant synergist can provide long-acting weather-resistant promotion and thermal oxygen stability, the toughening compatilizer can optimize the interfacial bonding state, the antioxidant can inhibit thermal oxygen degradation, the lubricant can improve the processing fluidity, and the corrosion-resistant filler can improve the medium resistance, which is beneficial to improving the mechanical properties, weather-resistant aging properties and corrosion-resistant properties of the modified engineering plastic.

Description

Technical Field

[0001] This application relates to the field of engineering plastics technology, and in particular to a modified engineering plastic and its preparation method. Background Technology

[0002] Polycarbonate, as an engineering plastic with excellent comprehensive properties, possesses advantages such as high strength, impact resistance, and good dimensional stability, and has been widely used in home appliances, construction, automotive interiors, and other fields. However, pure polycarbonate is susceptible to ultraviolet radiation, temperature and humidity fluctuations, and corrosive media during long-term service in natural environments, resulting in defects such as yellowing, insufficient weather resistance, and weak corrosion resistance. At the same time, the matrix itself has limited toughness, and problems such as poor flowability and uneven component dispersion are prone to occur during processing.

[0003] Existing modification methods mostly employ simple physical blending of additives, leading to easy migration and precipitation of functional components and rapid degradation of long-term weather resistance. Furthermore, conventional fillers exhibit poor interfacial bonding with the resin, only improving a single property and failing to simultaneously address both weather resistance and impact strength. Therefore, it is necessary to provide a modified engineering plastic that can effectively meet performance requirements. Summary of the Invention

[0004] The technical problem to be solved by this application is to solve at least one of the technical problems mentioned above.

[0005] The solution to the technical problem in this application is: In a first aspect, this application provides a modified engineering plastic, wherein the raw material comprises the following components in parts by weight: 55-72 parts polycarbonate resin, 5-12 parts weather-resistant synergist, 4-8 parts toughening compatibilizer, 1-3 parts antioxidant, 0.5-2 parts lubricant, and 2-5 parts corrosion-resistant filler; The raw materials for preparing the weather-resistant synergist include talc, 2-(2-hydroxy-5-methylphenyl)benzotriazole, N,N-bis(2,2,6,6-tetramethyl-4-piperidinyl)ethylenediamine, and maleic anhydride-grafted paraffin.

[0006] Furthermore, the preparation method of the weather-resistant synergist includes the following steps: The talc powder was dried and then activated with a silane coupling agent solution, followed by separation and drying. The 2-(2-hydroxy-5-methylphenyl)benzotriazole, the N,N-bis(2,2,6,6-tetramethyl-4-piperidinyl)ethylenediamine and the maleic anhydride-grafted paraffin were dispersed in a solvent and reacted at 100-120°C for 1-2 hours to obtain an intermediate solution. The activated talc powder is dispersed in the intermediate solution and mixed. The mixture is stirred continuously at 150-180°C for 2-3 hours. After separation and drying, the weather-resistant synergist is obtained.

[0007] Furthermore, the particle size of the talc powder is 800-1250 mesh; The mass ratio of the talc powder to the silane coupling agent solution is 1:9-15, and the silane coupling agent solution is prepared with ethanol and has a weight concentration of 5-10%. The weight ratio of the 2-(2-hydroxy-5-methylphenyl)benzotriazole, the N,N-bis(2,2,6,6-tetramethyl-4-piperidinyl)ethylenediamine, and the maleic anhydride-grafted paraffin is 3:1-2:5; the solvent is toluene. The weight ratio of the activated talc powder to the intermediate solution is 1:2-4.

[0008] Furthermore, the polycarbonate resin is an aromatic polycarbonate with a weight-average molecular weight of 20,000-35,000 and a melt flow rate of 6-10 g / 10 min.

[0009] Furthermore, the toughening compatibilizer is a combination of EPDM rubber and maleic anhydride-grafted POE, wherein the weight ratio of EPDM rubber to maleic anhydride-grafted POE is 2-3:1.

[0010] Furthermore, the lubricant is a combination of pentaerythritol stearate, lignite wax, and oxidized polyethylene wax, wherein the weight ratio of pentaerythritol stearate, lignite wax, and oxidized polyethylene wax is 1:2:4-6.

[0011] Further, the antioxidant is a combination of pentaerythritol tetrakis(3,5-di-tert-butyl-4-hydroxyphenyl)propionate and bis(2,4-di-tert-butylphenyl)pentaerythritol diphosphite, wherein the weight ratio of the antioxidant to pentaerythritol tetrakis(3,5-di-tert-butyl-4-hydroxyphenyl)propionate and bis(2,4-di-tert-butylphenyl)pentaerythritol diphosphite is 2-5:1.

[0012] Furthermore, the corrosion-resistant filler is a combination of mica powder and kaolin, wherein the weight ratio of mica powder to kaolin is 2-4:1, and the particle size of both mica powder and kaolin is 800-1250 mesh.

[0013] Secondly, this application provides a method for preparing the modified engineering plastic as described in the first aspect, comprising the following steps: The polycarbonate resin, the toughening compatibilizer, the antioxidant, the lubricant, and the corrosion-resistant filler are mixed in proportion and mixed at 100-120°C for 8-12 minutes to obtain a premix. The premix and the weather-resistant synergist are mixed and melt-blended in a twin-screw extruder at an extrusion temperature of 240-270°C, a screw speed of 250-350 r / min, and a screw length-to-diameter ratio of 40-48:1. The modified engineering plastic is obtained by stretching, cooling, and pelletizing.

[0014] The beneficial effects of this application are as follows: In this application, by rationally combining polycarbonate resin, weather-resistant synergist, toughening compatibilizer, antioxidant, lubricant and corrosion-resistant filler, each functional component can form a stable and synergistic composite system in the resin matrix. Weather-resistant synergist can provide long-lasting weather resistance improvement and thermo-oxidative stabilization, toughening compatibilizer can optimize the interphase interface bonding state, antioxidant can inhibit thermo-oxidative degradation during processing and use, lubricant can improve processing fluidity, and corrosion-resistant filler can construct a physical barrier structure to improve media resistance, which is beneficial to improving the mechanical properties, weather aging resistance and corrosion resistance of modified engineering plastics. Detailed Implementation

[0015] The following will clearly and completely describe the concept and technical effects of this application in conjunction with embodiments, so as to fully understand the purpose, features and effects of this application. Obviously, the described embodiments are only a part of the embodiments of this application, not all of them. Other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are all within the scope of protection of this application. The various technical features in this application can be combined interactively without contradicting each other.

[0016] This application provides a modified engineering plastic, wherein the raw material comprises the following components in parts by weight: 55-72 parts polycarbonate resin, 5-12 parts weather-resistant synergist, 4-8 parts toughening compatibilizer, 1-3 parts antioxidant, 0.5-2 parts lubricant, and 2-5 parts corrosion-resistant filler; The raw materials for preparing the weather-resistant synergist include talc, 2-(2-hydroxy-5-methylphenyl)benzotriazole, N,N-bis(2,2,6,6-tetramethyl-4-piperidinyl)ethylenediamine, and maleic anhydride-grafted paraffin.

[0017] In this application, by rationally combining polycarbonate resin, weather-resistant synergist, toughening compatibilizer, antioxidant, lubricant, and corrosion-resistant filler, the functional components can form a stable and synergistic composite system in the resin matrix. The weather-resistant synergist can provide long-lasting weather resistance enhancement and thermo-oxidative stabilization, the toughening compatibilizer can optimize the interphase interface bonding state, the antioxidant can inhibit thermo-oxidative degradation during processing and use, the lubricant can improve processing fluidity, and the corrosion-resistant filler can construct a physical barrier structure to enhance media resistance. This is beneficial to improving the mechanical properties, weather aging resistance, and corrosion resistance of modified engineering plastics.

[0018] Furthermore, the preparation method of the weather-resistant synergist includes the following steps: After drying, talc powder is activated by adding a silane coupling agent solution, followed by separation and drying. 2-(2-hydroxy-5-methylphenyl)benzotriazole, N,N-bis(2,2,6,6-tetramethyl-4-piperidinyl)ethylenediamine and maleic anhydride grafted paraffin were dispersed in a solvent and reacted at 100-120℃ for 1-2 h to obtain an intermediate solution. The activated talc powder was dispersed in an intermediate solution and mixed. The mixture was stirred continuously at 150-180℃ for 2-3 hours. After separation and drying, the weather-resistant synergist was obtained.

[0019] In this application, by activating talc powder with a silane coupling agent solution, active silanol groups and reactive groups can be introduced onto the surface of talc powder, thereby improving its surface energy and organic compatibility and providing stable sites for the subsequent bonding of functional components. By heating 2-(2-hydroxy-5-methylphenyl)benzotriazole, N,N-bis(2,2,6,6-tetramethyl-4-piperidinyl)ethylenediamine and maleic anhydride-grafted paraffin in a solvent, the components form coordination intermediates, which are then reacted with activated talc powder at high temperature. This allows weather-resistant functional molecules to be loaded onto the surface of talc powder through chemical bonding and physical adsorption, reducing the migration and precipitation of small molecule functional additives during high-temperature processing and long-term use. This is beneficial for improving the long-term weather resistance, light stability, and service life of modified engineering plastics.

[0020] Furthermore, the particle size of talc is 800-1250 mesh; The mass ratio of talc powder to silane coupling agent solution is 1:9-15. The silane coupling agent solution is prepared with ethanol and has a weight concentration of 5-10%. The weight ratio of 2-(2-hydroxy-5-methylphenyl)benzotriazole, N,N-bis(2,2,6,6-tetramethyl-4-piperidinyl)ethylenediamine, and maleic anhydride-grafted paraffin is 3:1-2:5; the solvent is toluene. The weight ratio of activated talc powder to intermediate solution is 1:2-4.

[0021] In this application, by limiting the particle size of talc powder to 800-1250 mesh, the filler can achieve both good dispersibility and interfacial bonding in the matrix, balancing reinforcement effect and processing fluidity. By controlling the ratio and concentration of talc powder to silane coupling agent solution, sufficient surface activation of talc powder can be achieved, avoiding uneven dispersion caused by local over-modification or insufficient activation. By optimizing the weight ratio of 2-(2-hydroxy-5-methylphenyl)benzotriazole, hindered amine component, and maleic anhydride grafted paraffin, the UV absorption function and free radical scavenging function are synergistically combined, while maleic anhydride grafted paraffin provides sufficient reaction sites and lubrication and dispersion effects. By limiting the ratio of activated talc powder to intermediate solution, the functional component loading is moderate and well distributed, which helps the overall structure of the weather-resistant synergist to be stable and its function to last, improving weather resistance, stability, and long-term reliability.

[0022] Furthermore, the polycarbonate resin is an aromatic polycarbonate with a weight average molecular weight of 20,000-35,000 and a melt flow rate of 6-10 g / 10 min.

[0023] In this application, aromatic polycarbonate resins with specific parameters are used, which enable the resin matrix to possess good rigidity, strength, heat resistance, and melt processing fluidity. This ensures that the final product has excellent mechanical properties and dimensional stability, and can fully wet filler particles and additive molecules in the molten state. It also has good compatibility distribution with components such as weather-resistant synergists, reducing interfacial voids, stress concentration, and phase separation defects, which is beneficial to balancing the processing efficiency and long-term performance of the material.

[0024] Furthermore, the toughening compatibilizer is a combination of EPDM rubber and maleic anhydride-grafted POE, with a weight ratio of EPDM rubber to maleic anhydride-grafted POE of 2-3:1.

[0025] In this application, EPDM rubber and maleic anhydride-grafted POE are compounded in a specific ratio as a toughening compatibilizer. This allows the elastomer dispersion phase to form a reasonable particle size and morphology in the matrix, effectively absorbing impact energy, alleviating stress concentration, and significantly improving the brittleness of polycarbonate materials. At the same time, the polar anhydride groups contained in the maleic anhydride-grafted POE can form hydrogen bonds and chemical bonds with the polycarbonate molecular chains, fillers, and weather-resistant synergists, strengthening the interfacial bonding strength, reducing the risk of interfacial debonding and crack initiation. This allows the material to significantly improve impact toughness without significantly losing rigidity and strength, which is beneficial for significantly improving the notched impact strength, crack resistance, and low-temperature resistance of the material.

[0026] Furthermore, the lubricant is a combination of pentaerythritol stearate, lignite wax and oxidized polyethylene wax, with a weight ratio of pentaerythritol stearate, lignite wax and oxidized polyethylene wax of 1:2:4-6.

[0027] In this application, a lubrication system composed of pentaerythritol stearate, lignite wax and oxidized polyethylene wax in a specific ratio is used. This system can reduce the internal friction and entanglement resistance between polymer molecular chains, reduce melt viscosity and processing energy consumption, reduce the adhesion and friction between the melt and the metal surfaces of the screw, barrel and mold, improve melt flow and demolding effect, effectively avoid resin degradation, yellowing and mechanical property decline caused by shear overheating, improve the stability of the processing process, the surface smoothness of the product, and extend the service life of production equipment and molds.

[0028] Furthermore, the antioxidant is a combination of pentaerythritol tetrakis(3,5-di-tert-butyl-4-hydroxyphenyl)propionate and bis(2,4-di-tert-butylphenyl)pentaerythritol diphosphite, wherein the weight ratio of the antioxidant to pentaerythritol tetrakis(3,5-di-tert-butyl-4-hydroxyphenyl)propionate and bis(2,4-di-tert-butylphenyl)pentaerythritol diphosphite is 2-5:1.

[0029] In this application, a compound antioxidant system of pentaerythritol tetrakis(3,5-di-tert-butyl-4-hydroxyphenyl)propionate and bis(2,4-di-tert-butylphenyl)pentaerythritol diphosphite is used. This system enables the main and auxiliary antioxidants to form a highly efficient and synergistic thermo-oxidative protection mechanism. The hindered phenolic main antioxidant can quickly capture alkyl radicals, alkoxy radicals and peroxy radicals in the system, effectively blocking the thermo-oxidative degradation chain reaction. The phosphite auxiliary antioxidant can efficiently decompose the hydroperoxides generated during oxidation, reducing the generation of active degradation products. The combination of the two can significantly inhibit the molecular chain breakage, yellowing and strength decay of the resin during high-temperature extrusion and long-term service, which is beneficial to greatly improve the material's thermo-oxidative aging resistance, color stability and mechanical property retention.

[0030] Furthermore, the corrosion-resistant filler is a combination of mica powder and kaolin, with a weight ratio of mica powder to kaolin of 2-4:1, and the particle size of both mica powder and kaolin is 800-1250 mesh.

[0031] In this application, mica powder and kaolin are compounded in a specific ratio as corrosion-resistant fillers. This allows the flaky mica and granular kaolin to form a dense physical barrier structure with interlaced layers in the resin matrix, effectively delaying the penetration and diffusion of moisture, oxygen, and corrosive media into the material and reducing the erosive effect of the media on the matrix. Both have a particle size of 800-1250 mesh, which ensures uniform dispersion of the filler and tight interfacial bonding. This not only improves the resistance to media corrosion but also enhances the rigidity, hardness, and dimensional stability of the material, which is beneficial for improving the material's tolerance and long-term reliability in humid and corrosive environments.

[0032] This application also provides you with a method for preparing the modified engineering plastic as described above, wherein the method includes the following steps: Polycarbonate resin, toughening compatibilizer, antioxidant, lubricant and corrosion-resistant filler are mixed in proportion and mixed at 100-120℃ for 8-12 minutes to obtain a premix. The premix and weather-resistant synergist are mixed and added to a twin-screw extruder for melt blending. The extrusion temperature is 240-270℃, the screw speed is 250-350r / min, and the screw length-to-diameter ratio is 40-48:1. After stretching, cooling, and pelletizing, the modified engineering plastic is obtained.

[0033] In this application, the basic components are premixed first, then mixed with the weather-resistant synergist and granulated by twin-screw extrusion to avoid component segregation. The melt blending process ensures that the components are fully dispersed and the interface is fully bonded, effectively reducing problems such as agglomeration, material shortage and performance fluctuation.

[0034] The following specific examples provide further details.

[0035] The preparation method of the weather-resistant synergist used in the embodiments and comparative examples of this application includes the following steps: After drying, talc powder is activated by adding a silane coupling agent solution, followed by separation and drying. 2-(2-hydroxy-5-methylphenyl)benzotriazole, N,N-bis(2,2,6,6-tetramethyl-4-piperidinyl)ethylenediamine and maleic anhydride grafted paraffin were dispersed in toluene and reacted at 120°C for 2 h to obtain an intermediate solution. Talc powder was dispersed in an intermediate solution and mixed. The mixture was stirred continuously at 160°C for 3 hours. After separation and drying, the weather-resistant synergist was obtained.

[0036] The talc powder has a particle size of 1000 mesh; the mass ratio of talc powder to silane coupling agent solution is 1:12, the silane coupling agent solution is prepared with ethanol and has a weight concentration of 8%; the weight ratio of 2-(2-hydroxy-5-methylphenyl)benzotriazole, N,N-bis(2,2,6,6-tetramethyl-4-piperidinyl)ethylenediamine and maleic anhydride grafted paraffin is 3:2:5; and the weight ratio of activated talc powder to intermediate solution is 1:3.

[0037] The preparation method of the engineering plastics in the embodiments and comparative examples of this application includes the following steps: Aromatic polycarbonate, ethylene propylene diene monomer (EPDM) rubber, maleic anhydride-grafted POE, pentaerythritol tetrakis(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, bis(2,4-di-tert-butylphenyl)pentaerythritol diphosphite, pentaerythritol stearate, lignite wax, oxidized polyethylene wax, mica powder, and kaolin were mixed in proportion and mixed at 110°C for 10 min to obtain a premix. The premix and weather-resistant synergist are mixed and added to a twin-screw extruder for melt blending. The extrusion temperature is 150℃, the screw speed is 300r / min, and the screw length-to-diameter ratio is 44:1. After stretching, cooling, and pelletizing, the modified engineering plastic is obtained.

[0038] The aromatic polycarbonate has a weight-average molecular weight of 30,000 and a melt flow rate of 8 g / 10 min; the mica powder and kaolin both have a particle size of 1,000 mesh.

[0039] The component ratios of the modified engineering plastics in Examples 1-5 of this application are shown in Table 1: Table 1 The component ratios of the plastic alloys in Comparative Examples 1-6 of this application are shown in Table 2: Table 2 The component ratios and preparation methods of Comparative Example 6 are basically the same as those of Example 1, except that talc powder is used in Comparative Example 6 instead of weather-resistant synergists.

[0040] The component ratios of the plastic alloys in Comparative Examples 7-12 of this application are shown in Table 3: Table 3 The engineering plastics obtained in Examples 1-6 and Comparative Examples 1-11 were subjected to performance tests, including: (1) Notched impact strength test: The specimen was processed into a standard notched strip specimen with a notch depth of 1 / 3 of the specimen thickness. Before the test, the specimen was placed at room temperature for 24 hours and the ambient temperature was maintained at 23±2℃. The specimen was subjected to impact test using a pendulum impact testing machine, and the fracture absorption energy was recorded. Five specimens were tested in each group. The maximum and minimum values ​​were removed, and the average value was taken as the result. The pendulum energy was 2.75J, the specimen size was 80×10×4mm, the notch type was V, and the unit of notched impact strength was kJ / m. 2 ; (2) The sample was processed into a flat sample piece with a size of 50×50×2mm. The surface of the sample piece was wiped with anhydrous ethanol to remove oil and impurities. It was then air-dried naturally. The initial yellowness value of the sample was tested using a colorimeter and recorded as Y0. Three different points on the sample piece were selected during the test, and the average value was taken as the initial data. The sample was placed in a device simulating natural aging environment for long-term aging test, simulating the comprehensive aging conditions of natural light, temperature and humidity changes. After aging, the sample was taken out and placed in a room temperature environment for 2 hours. After the sample temperature was consistent with the ambient temperature, the yellowness value was tested again using a colorimeter and recorded as Y1. The yellowness change value was calculated according to the formula: ΔY=Y1-YY0. The smaller ΔY is, the better the weather resistance and yellowing performance of the material, and the more significant the weather resistance enhancer effect. The aging light source simulated natural light (including UVA and UVB bands) with a light intensity of 1.2W / m. 2 @340nm, temperature cycling (60℃ during the day, 30℃ at night), relative humidity 60±5%, aging time: 200h, colorimeter test mode: D65 light source, 10° standard observation angle, test result yellowness change value (ΔY). The closer the value is to 0, the better the material's weather resistance and yellowing performance.

[0041] (3) Test for resistance to corrosion by media: The initial mass of the test sample is recorded as M0. The sample is completely immersed in the simulated corrosive liquid and kept at a constant temperature. After the time is up, the sample is taken out, the surface droplets are dried with filter paper, and the weight is recorded as M1. The mass change rate (%) is calculated as: |M1−M0| / M0×100%. The corrosive medium is a 5% neutral salt solution. The immersion temperature is 40℃ and the immersion time is 72h. The smaller the mass change rate (%), the better the corrosion resistance.

[0042] The performance test results of Examples 1-6 and Comparative Examples 1-11 of this application are shown in Table 4: Table 4 Comparative test results show that the modified engineering plastics prepared in Examples 1-6 of this application have relatively balanced overall performance. Example 1 shows better overall performance, with higher notched impact strength, weather resistance, and resistance to media corrosion. Comparative Examples 1-5 are missing one key component: weather synergist, toughening compatibilizer, antioxidant, lubricant, and corrosion-resistant filler, respectively. The absence of the weather synergist significantly increases the yellowing difference and greatly deteriorates the weather resistance. The absence of the toughening compatibilizer causes a significant decrease in impact strength. The absence of the antioxidant exacerbates long-term weather yellowing. The absence of the corrosion-resistant filler leads to a significant increase in the rate of change in quality due to media corrosion. The absence of the lubricant has a relatively small impact on the overall performance, but it can easily affect the processing performance. Comparative Example 6 uses ordinary talc to replace the weather synergist of this application, and the weather resistance and corrosion resistance of the material are significantly worse than those of the examples. Therefore, the weather synergist in Comparative Example 6 has a weather-enhancing effect compared to ordinary talc. In Comparative Examples 7-11, excessive amounts of a single component did not lead to a simultaneous improvement in performance; instead, they resulted in slight decreases in toughness, weather resistance, or corrosion resistance to varying degrees. This indicates that each component in this application has an optimal mixing ratio range, and excessive addition can easily cause problems such as uneven dispersion and poor interfacial compatibility, which are detrimental to the overall performance of the material. The formulation and combination design provided in this application enable the material to achieve a synergistic improvement in impact strength and weather resistance.

[0043] The preferred embodiments of this application have been described in detail above, but the invention of this application is not limited to the embodiments described. Those skilled in the art can make various equivalent modifications or substitutions without departing from the spirit of this application, and these equivalent modifications or substitutions are all included within the scope defined by the claims of this application.

Claims

1. A modified engineering plastic, characterized in that, By weight, the raw materials comprise the following components: 55-72 parts polycarbonate resin, 5-12 parts weather-resistant synergist, 4-8 parts toughening compatibilizer, 1-3 parts antioxidant, 0.5-2 parts lubricant, and 2-5 parts corrosion-resistant filler; The raw materials for preparing the weather-resistant synergist include talc, 2-(2-hydroxy-5-methylphenyl)benzotriazole, N,N-bis(2,2,6,6-tetramethyl-4-piperidinyl)ethylenediamine, and maleic anhydride-grafted paraffin.

2. The modified engineering plastic according to claim 1, characterized in that, The preparation method of the weather-resistant synergist includes the following steps: The talc powder was dried and then activated with a silane coupling agent solution, followed by separation and drying. The 2-(2-hydroxy-5-methylphenyl)benzotriazole, the N,N-bis(2,2,6,6-tetramethyl-4-piperidinyl)ethylenediamine and the maleic anhydride-grafted paraffin were dispersed in a solvent and reacted at 100-120°C for 1-2 hours to obtain an intermediate solution. The activated talc powder is dispersed in the intermediate solution and mixed. The mixture is stirred continuously at 150-180°C for 2-3 hours. After separation and drying, the weather-resistant synergist is obtained.

3. The modified engineering plastic according to claim 2, characterized in that, The talc powder has a particle size of 800-1250 mesh; The mass ratio of the talc powder to the silane coupling agent solution is 1:9-15, and the silane coupling agent solution is prepared with ethanol and has a weight concentration of 5-10%. The weight ratio of the 2-(2-hydroxy-5-methylphenyl)benzotriazole, the N,N-bis(2,2,6,6-tetramethyl-4-piperidinyl)ethylenediamine, and the maleic anhydride-grafted paraffin is 3:1-2:5; the solvent is toluene. The weight ratio of the activated talc powder to the intermediate solution is 1:2-4.

4. The modified engineering plastic according to claim 2, characterized in that, The polycarbonate resin is an aromatic polycarbonate with a weight average molecular weight of 20,000-35,000 and a melt flow rate of 6-10 g / 10 min.

5. The modified engineering plastic according to claim 2, characterized in that, The toughening compatibilizer is a combination of EPDM rubber and maleic anhydride-grafted POE, wherein the weight ratio of EPDM rubber to maleic anhydride-grafted POE is 2-3:

1.

6. The modified engineering plastic according to claim 2, characterized in that, The lubricant is a combination of pentaerythritol stearate, lignite wax and oxidized polyethylene wax, wherein the weight ratio of pentaerythritol stearate, lignite wax and oxidized polyethylene wax is 1:2:4-6.

7. The modified engineering plastic according to claim 2, characterized in that, The antioxidant is a combination of pentaerythritol tetrakis(3,5-di-tert-butyl-4-hydroxyphenyl)propionate and bis(2,4-di-tert-butylphenyl)pentaerythritol diphosphite, wherein the weight ratio of the antioxidant to pentaerythritol tetrakis(3,5-di-tert-butyl-4-hydroxyphenyl)propionate and bis(2,4-di-tert-butylphenyl)pentaerythritol diphosphite is 2-5:

1.

8. The modified engineering plastic according to claim 2, characterized in that, The corrosion-resistant filler is a combination of mica powder and kaolin, with a weight ratio of mica powder to kaolin of 2-4:1, and both mica powder and kaolin have a particle size of 800-1250 mesh.

9. A method for preparing a modified engineering plastic as described in any one of claims 1-8, characterized in that, Includes the following steps: The polycarbonate resin, the toughening compatibilizer, the antioxidant, the lubricant, and the corrosion-resistant filler are mixed in proportion and mixed at 100-120°C for 8-12 minutes to obtain a premix. The premix and the weather-resistant synergist are mixed and melt-blended in a twin-screw extruder at an extrusion temperature of 240-270°C, a screw speed of 250-350 r / min, and a screw length-to-diameter ratio of 40-48:

1. The modified engineering plastic is obtained by stretching, cooling, and pelletizing.

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