High-weather-resistance polycarbonate composite material and preparation method thereof

Abstract

The invention provides a high-weather-resistant polycarbonate composite material and a preparation method thereof, and relates to the technical field of composite material preparation, the high-weather-resistant polycarbonate composite material comprises the following components by weight: 70-90 parts of polycarbonate, 1-3 parts of a weather-resistant stable system, and 3-8 parts of a nano inorganic filler, the weather-resistant stable system comprises an ultraviolet light absorber, an antioxidant and a metal deactivator, the ultraviolet light absorber is a benzotriazole compound, the antioxidant is a compound of hindered phenol and phosphite ester compounds, and the metal deactivator is selected from N, N '-diphenyl oxamide; the nano inorganic filler is selected from one or more of nano titanium dioxide, nano silicon dioxide and nano aluminum oxide, and the polycarbonate composite material has excellent damp-heat aging resistance stability.

Description

Technical Field

[0001] This invention relates to the field of composite material preparation technology, specifically to high weather-resistant polycarbonate composite materials and their preparation methods. Background Technology

[0002] Polycarbonate (PC) is a thermoplastic engineering plastic with excellent comprehensive properties, including superior impact strength, transparency, dimensional stability, and electrical insulation. It is widely used in the automotive, electronics, construction, and medical equipment industries.

[0003] Polycarbonate products used in automobiles and construction are often applied outdoors. During outdoor use, they are exposed to environmental factors such as ultraviolet radiation, heat, oxygen, and humidity, which can cause polycarbonate to undergo photo-oxidative aging, leading to yellowing and a decline in mechanical properties. Especially under high temperature and high humidity conditions (such as D85 test conditions: 85℃ / 85% relative humidity), polycarbonate is prone to hydrolytic degradation and molecular chain breakage, resulting in a sharp decline in performance. Therefore, providing a highly weather-resistant polycarbonate composite material with excellent resistance to damp heat aging has become a pressing technical problem for those skilled in the art. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a high weather-resistant polycarbonate composite material and its preparation method, solving the technical problem of performance degradation of polycarbonate under high temperature and high humidity environments.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] In a first aspect, the present invention provides a high weather-resistant polycarbonate composite material, comprising the following components in parts by weight:

[0007] 70-90 parts polycarbonate;

[0008] 1-3 parts of weather-resistant stabilizing system;

[0009] 3-8 parts of nano-inorganic filler.

[0010] The weather-resistant stabilizing system includes an ultraviolet absorber, an antioxidant, and a metal passivator. The ultraviolet absorber is a benzotriazole compound, the antioxidant is a compound of hindered phenols and phosphites (compound ratio 1:1-3), and the metal passivator is N,N'-diphenyloxazone.

[0011] The nano-inorganic filler is selected from one or more of nano-titanium dioxide, nano-silica, and nano-alumina.

[0012] The aforementioned high weather-resistant polycarbonate composite material includes a weather-stabilizing system and nano-inorganic fillers. The weather-stabilizing system includes ultraviolet absorbers, antioxidants, and metal passivators. The nano-inorganic fillers are selected from one or more of nano-titanium dioxide, nano-silica, and nano-alumina. The weather-stabilizing system can effectively inhibit the photo-oxidative aging and hydrolytic degradation of polycarbonate under high temperature and high humidity environments, while the nano-inorganic fillers can improve the heat resistance of polycarbonate. Therefore, the synergistic effect of the weather-stabilizing system and the nano-inorganic fillers improves the stability of the polycarbonate composite material against damp heat aging.

[0013] Preferably, the weight ratio of the ultraviolet absorber, antioxidant and metal passivator is 0.4-1:0.3-0.5:0.1-0.5.

[0014] By controlling the weight ratio of ultraviolet absorbers, antioxidants, and metal passivators within a suitable range, the weather-resistant stabilizing system and nano-inorganic fillers can work synergistically to improve the hygrothermal aging stability of polycarbonate composites.

[0015] Preferably, the nano-inorganic filler has an average particle size of 20-80 nm and its surface is treated with a silane coupling agent.

[0016] By controlling the average particle size of the nano-inorganic filler within a suitable range, the weather-resistant stabilizing system and the nano-inorganic filler can work synergistically to improve the hygrothermal aging stability of polycarbonate composites.

[0017] Preferably, the high weather-resistant polycarbonate composite material further comprises a phosphorus-based flame retardant, 20% silicon-containing polydimethylsiloxane, and sulfonate, wherein the weight ratio of the phosphorus-based flame retardant, 20% silicon-containing polydimethylsiloxane, and sulfonate is 5-12:2-8:0.5-3.

[0018] Polycarbonate composites were prepared using phosphorus-based flame retardants, polydimethylsiloxane with 20% silicon content, and sulfonates. During combustion, these components simultaneously exert flame-retardant effects in both the gas and condensed phases, promoting char formation and inhibiting combustion. Furthermore, the flame-retardant material migrates to the surface of the polycarbonate composite to form a protective layer. Therefore, phosphorus-based flame retardants, polydimethylsiloxane with 20% silicon content, and sulfonates have a synergistic effect in improving the flame retardancy of polycarbonate composites. This results in the formation of a dense char layer during combustion, effectively suppressing dripping and achieving a UL94 V-0 flame retardant rating (1.6 mm) with a limiting oxygen index exceeding 32%.

[0019] Preferably, the phosphorus-based flame retardant is selected from one or more combinations of resorcinol bis(diphenyl phosphate) RDP, bisphenol A bis(diphenyl phosphate) BDP, and triphenyl phosphate TPP.

[0020] Preferably, the polydimethylsiloxane is a hydroxyl-terminated polydimethylsiloxane with a viscosity-average molecular weight of 5000-20000 g / mol.

[0021] Preferably, the sulfonate is selected from one or more of potassium perfluorobutyl sulfonate, sodium benzenesulfonate, and sodium 2,4,5-trichlorobenzenesulfonate.

[0022] Preferably, the high weather-resistant polycarbonate composite material further comprises a styrene-acrylonitrile-glycidyl methacrylate copolymer.

[0023] Choosing a styrene-acrylonitrile-glycidyl methacrylate copolymer improves the toughness of polycarbonate composites, enabling the notched impact strength of the polycarbonate composite to be no less than 25 kJ / m² at -40℃, thus overcoming the disadvantage of high low-temperature brittleness of traditional polycarbonate.

[0024] Preferably, in the styrene-acrylonitrile-glycidyl methacrylate copolymer, the weight ratio of styrene, acrylonitrile, and glycidyl methacrylate is (65-75):(20-30):(5-10), and its weight-average molecular weight is 80,000-150,000 g / mol. The glycidyl methacrylate groups can react with the polycarbonate end groups to form a synergistic compatibilizing network, improving interfacial bonding.

[0025] Preferably, the high weather-resistant polycarbonate composite material further includes processing aids, such as lubricants and anti-dripping agents.

[0026] Preferably, the polycarbonate is a bisphenol A type aromatic polycarbonate with a weight-average molecular weight of 25,000-35,000 g / mol and a melt volumetric flow rate (300°C, 1.2 kg load) of 8-15 cm³ / 10 min. Polycarbonates with too low a molecular weight have insufficient mechanical properties, while polycarbonates with too high a molecular weight have poor processing fluidity.

[0027] In a second aspect, the present invention provides a method for preparing the high weather-resistant polycarbonate composite material described in the first aspect, comprising the following steps:

[0028] Polycarbonate and styrene-acrylonitrile-glycidyl methacrylate copolymer are dried and then mixed with other components to obtain a premix. The premix is ​​melt-blended at 180-275℃ and cooled to obtain a high weather-resistant polycarbonate composite material.

[0029] Preferably, the preparation method of the high weather-resistant polycarbonate composite material includes the following steps:

[0030] (1) Raw material pretreatment: The polycarbonate was dried in a forced air at 120°C for 4-6 hours, and the styrene-acrylonitrile-glycidyl methacrylate copolymer was dried in a forced air at 80°C for 4-6 hours to remove moisture and prevent hydrolysis and degradation during processing;

[0031] (2) Premixing: The dried polycarbonate, styrene-acrylonitrile-glycidyl methacrylate copolymer and other components are placed in a high-speed mixer and mixed for 8-15 minutes to obtain a uniform premix.

[0032] (3) Melt blending: The premix is ​​melt blended through a twin-screw extruder. The extruder temperature range is 180-275℃ and the screw speed is 200-400 rpm.

[0033] (4) Granulation: The extruded melt is cooled in a water bath and granulated to obtain a high weather-resistant and flame-retardant polycarbonate composite material.

[0034] Preferably, the twin-screw extruder includes a feeding zone, a melting zone, a mixing zone, and a homogenizing zone arranged sequentially. The mixing zone is equipped with multiple sets of kneading blocks. The temperature of the melting zone is 240-260°C, and the temperature of the mixing zone is 250-270°C. This screw configuration and temperature setting ensures thorough melting and mixing of the material while avoiding excessive heat history that could lead to material degradation.

[0035] Compared with existing technologies, it has the following beneficial effects:

[0036] 1. The high weather-resistant polycarbonate composite material provided in this application includes a weather-stabilizing system and nano-inorganic fillers. The weather-stabilizing system includes ultraviolet absorbers, antioxidants, and metal passivators. The nano-inorganic fillers are selected from one or more of nano-titanium dioxide, nano-silica, and nano-alumina. The weather-stabilizing system can effectively inhibit the photo-oxidative aging and hydrolytic degradation of polycarbonate under high temperature and high humidity environments, while the nano-inorganic fillers can improve the heat resistance of polycarbonate. Therefore, the synergistic effect of the weather-stabilizing system and the nano-inorganic fillers improves the stability of the polycarbonate composite material under humid heat aging. After aging for 1000 hours in an environment of 85℃ / 85% relative humidity, the tensile strength retention rate of the polycarbonate composite material is not less than 90%, and the yellowing index ΔYI is less than 4.

[0037] 2. The high weather-resistant polycarbonate composite material provided in this application also includes a phosphorus-based flame retardant, 20% silicon-containing polydimethylsiloxane, and sulfonates. The weight ratio of the phosphorus-based flame retardant, 20% silicon-containing polydimethylsiloxane, and sulfonates is 5-12:2-8:0.5-3. Through the synergistic effect of the phosphorus-based flame retardant, 20% silicon-containing polydimethylsiloxane, and sulfonates, the polycarbonate composite forms a dense char layer during combustion, effectively suppressing dripping and achieving a UL94 V-0 flame retardant rating (1.6mm) with a limiting oxygen index of over 32%.

[0038] 3. The high weather-resistant polycarbonate composite material provided in this application also includes a styrene-acrylonitrile-glycidyl methacrylate copolymer, which improves the toughness of the polycarbonate composite material, ensuring that the notched impact strength of the cantilever beam of the polycarbonate composite material is not less than 25 kJ / m at -40℃. 2 This overcomes the shortcomings of traditional polycarbonate, such as high brittleness at low temperatures.

[0039] 4. The high weather-resistant polycarbonate composite material provided in this application maintains high flame retardancy and weather resistance while exhibiting excellent and balanced mechanical properties. The tensile strength of the material can reach over 55 MPa, the flexural strength can reach over 80 MPa, and the notched impact strength of the cantilever beam (23℃) can reach 45 kJ / m. 2 above. Detailed Implementation

[0040] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention are described clearly and completely. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0041] To better understand the above technical solution, the following will provide a detailed explanation of the above technical solution in conjunction with specific implementation methods.

[0042] I. Preparation Method

[0043] Example 1

[0044] This embodiment provides a method for preparing a high weather-resistant polycarbonate composite material, comprising the following steps:

[0045] (1) Raw material pretreatment: Polycarbonate was dried in a forced air at 120°C for 5 hours, and styrene-acrylonitrile-glycidyl methacrylate copolymer was dried in a forced air at 80°C for 5 hours;

[0046] (2) Premixing: The dried polycarbonate, styrene-acrylonitrile-glycidyl methacrylate copolymer and other components are mixed in a high-speed mixer for 10 minutes according to the amounts (parts by weight) in Table 1 to obtain the premix;

[0047] The surface of the nano-inorganic filler is treated with a silane coupling agent, which includes the following steps: the filler is vacuum dried at 110℃ for 4 hours; 1.0% of the silane coupling agent by weight of the filler is dissolved in an ethanol / water mixed solvent and hydrolyzed for 30 minutes to form a hydrolysate; the dried filler is added to the hydrolysate, and the mixture is mechanically stirred at 50℃ and ultrasonically dispersed for 2 hours; after the reaction, the mixture is centrifuged, the solid product is washed with ethanol, and vacuum dried at 80℃ for 8 hours to obtain the surface-treated nano-inorganic filler.

[0048] (3) Melt blending: The premix is ​​melt blended through a twin-screw extruder. The extruder temperature from the feed inlet to the die head is set as follows: 180℃, 255℃, 260℃, 262℃, 265℃, 262℃, 260℃, 258℃, 262℃, 268℃, the die head temperature is 270℃, and the screw speed is 300 rpm.

[0049] (4) Granulation: The extruded melt is cooled in a water bath and granulated to obtain a high weather-resistant polycarbonate composite material.

[0050] The polycarbonate is a bisphenol A type aromatic polycarbonate with a weight-average molecular weight of 25,000 g / mol and a melt volumetric flow rate (300℃, 1.2 kg load) of 8 cm⁻¹. 3 / 10min, model number TEIJIN LIMITED Panlite® L-1250Y;

[0051] The styrene-acrylonitrile-glycidyl methacrylate copolymer has a weight ratio of styrene, acrylonitrile, and glycidyl methacrylate of 70:25:5, and the manufacturer is JARYUNG.

[0052] The phosphorus-based flame retardant is resorcinol bis(diphenyl phosphate) RDP;

[0053] The ultraviolet absorber is a benzotriazole compound, UV-326;

[0054] The antioxidant is a compound of hindered phenolic and phosphite compounds, with a ratio of 1:2.

[0055] The metal passivating agent is N,N'-diphenyloxam;

[0056] The average particle size of nano-TiO2 is 20 nm;

[0057] The lubricant is dipentaerythritol stearate;

[0058] The anti-dripping agent is modified polytetrafluoroethylene;

[0059] Polydimethylsiloxane with 20% silicon content, manufactured by Cangzhou Dahua, model number CH9030LT.

[0060] Example 2-3

[0061] The difference between Examples 2-3 and Example 1 is that the amounts of each component are different, as shown in Table 1. Everything else is the same as in Example 1.

[0062] Comparative Examples 1-4

[0063] The difference between Comparative Examples 1-4 and Example 1 is that the amounts of each component in the weather-resistant stable system are different, as shown in Table 2. The rest is the same as in Example 1.

[0064] Comparative Examples 5-7

[0065] The difference between Comparative Examples 5-7 and Example 1 is that the amount of each component in the flame retardant system is different, as shown in Table 3. The rest is the same as in Example 1.

[0066] Comparative Example 8

[0067] The difference between Comparative Example 8 and Example 1 is that step (2) does not include styrene-acrylonitrile-glycidyl methacrylate copolymer, and the amount of polycarbonate is 90 parts, as shown in Table 3. The rest is the same as in Example 1.

[0068] Table 1. Components and dosages in Examples 1-3

[0069]

[0070] Table 2. Components and dosages in Comparative Examples 1-4

[0071]

[0072] Table 3. Components and dosages in Comparative Examples 5-8

[0073]

[0074] II. Testing Methods

[0075] The high weather-resistant polycarbonate composite materials prepared in Examples 1-3 and Comparative Examples 1-8 were poured into the feed port of an injection molding machine and injection molded into corresponding specimens and templates according to the required process parameters. The relevant properties of the specimens and templates were tested. The specific test items and methods are as follows:

[0076] 1. Flame retardant rating: UL94 standard, specifically, the sample (125mm×13mm) is pretreated under standard conditions (23℃, 50% RH) and aging conditions (70℃, 168h) and then subjected to a 20mm vertical burning test. If the total burning time (t1+t2) of the five samples is ≤50 seconds, the single burning time (t1 or t2) of any sample is ≤10 seconds, and the burning drips do not ignite the absorbent cotton below, it is judged as V-0 level; if the total burning time (t1+t2) of the five samples is ≤250 seconds, the single burning time (t1 or t2) of any sample is ≤30 seconds, and the burning drips do not ignite the absorbent cotton below, it is judged as V-1 level; if the total burning time (t1+t2) of the five samples is ≤250 seconds, the single burning time (t1 or t2) of any sample is ≤30 seconds, and the burning drips do not ignite the absorbent cotton below, it is judged as V-1 level, but it is allowed for the burning drips to ignite the absorbent cotton, and it is judged as V-2 level.

[0077] 2. Limiting oxygen index: Tested according to ASTM D2863 standard, with a sample size of 80mm×10mm×4mm, using an oxygen index meter and the top surface ignition method.

[0078] 3. Tensile strength: Tested according to ISO 527 standard, with a tensile speed of 50 mm / min.

[0079] 4. Bending strength: Tested according to ISO 178 standard, bending speed 2mm / min.

[0080] 5. Cantilever beam notched impact strength: Tested according to ISO 180 standard, the specimen is a standard notched specimen (size is 80mm x 10mm x 4mm, type A notch).

[0081] 6. Resistance to damp heat aging: The performance changes were tested after the sample was placed in a constant temperature and humidity chamber at 85℃ / 85% relative humidity for 1000 hours. Specifically:

[0082] (1) Tensile strength retention rate: The tensile strength retention rate is calculated based on the test values ​​before and after aging.

[0083] (2) Color change: Tested according to ASTM D2244 standard using a colorimeter.

[0084] (3) Impact strength retention rate: The impact strength retention rate is calculated based on the test values ​​before and after aging.

[0085] III. Test Results

[0086] The performance test results of the high weather-resistant polycarbonate composite materials prepared in Examples 1-3 and Comparative Examples 1-8 are shown in Table 4.

[0087] Table 4. Performance test results of high weather-resistant polycarbonate composite materials in the examples and comparative examples.

[0088]

[0089] As shown in Table 4, the polycarbonate composite material prepared in Example 1 retained 92.5% of its tensile strength, had a yellowing index ΔYI of 3.2, and an impact strength retention rate of 89.5% after D85 testing. In contrast, the polycarbonate composite materials prepared in Comparative Examples 1 (lacking UV absorber), 2 (lacking antioxidant), 3 (lacking metal passivator), and 4 (lacking nano-TiO2) only retained about 75.7% of their tensile strength, had a yellowing index ΔYI of 8.9, and an impact strength retention rate of only 66.0% after D85 testing. They could not achieve the excellent resistance to humid heat aging as in Example 1. Therefore, UV absorber, antioxidant, metal passivator, and nano-TiO2 have a synergistic effect in improving the resistance to humid heat aging of polycarbonate composite materials.

[0090] The polycarbonate composite material prepared in Example 1 has a UL94 rating of V-0 and a limiting oxygen index of 32.5%. The polycarbonate composite materials prepared in Comparative Example 5 (lacking phosphorus-based flame retardant), Comparative Example 6 (lacking polydimethylsiloxane with 20% silicon content), and Comparative Example 7 (lacking potassium perfluorobutylsulfonate) have a UL94 rating of V-1 or V-2 and a limiting oxygen index of approximately 27.5%. Therefore, phosphorus-based flame retardant, polydimethylsiloxane with 20% silicon content, and potassium perfluorobutylsulfonate have a synergistic effect in providing flame retardancy to polycarbonate composite materials.

[0091] The composite material prepared in Example 1 has a notched impact strength of 26.8 kJ / m at -40℃ for the cantilever beam. 2 The notched impact strength of the polycarbonate composite material prepared without the addition of styrene-acrylonitrile-glycidyl methacrylate copolymer in Comparative Example 8 was 16.5 kJ / m at -40°C. 2 Therefore, the technical solution of this application includes a styrene-acrylonitrile-glycidyl methacrylate copolymer, which improves the low-temperature impact toughness of the prepared polycarbonate composite material.

[0092] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0093] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

[0094] The present invention has been illustrated with the above embodiments to describe the detailed process flow of the present invention. However, the present invention is not limited to the above detailed process flow, that is, it does not mean that the present invention must rely on the above detailed process flow to be implemented. Those skilled in the art should understand that any improvements to the present invention, equivalent substitutions of the raw materials of the product of the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A highly weatherable polycarbonate composite material, characterized in that, The components include the following weight parts: Polycarbonate 70-90 parts; Weather-resistant stabilizing system 1-3 parts; Nano-inorganic filler 3-8 parts; The weather-resistant stabilizing system includes ultraviolet absorber, antioxidant and metal deactivator, the ultraviolet absorber is benzotriazole compound, the antioxidant is a compound of hindered phenol and phosphite, and the metal deactivator is selected from N, N'-diphenyl oxamide; The compound weight ratio of the hindered phenol compound and the phosphite compound is 1:1-3; The nano-inorganic filler is selected from one or more of nano-titanium dioxide, nano-silicon dioxide and nano-aluminum oxide.

2. The high-weatherable polycarbonate composite of claim 1, wherein, The weight ratio of the ultraviolet absorber, antioxidant and metal deactivator is 0.4-1:0.3-0.5:0.1-0.

5.

3. The high-weatherable polycarbonate composite of claim 1, wherein, The average particle size of the nano-inorganic filler is 20-80 nm, and the surface of the nano-inorganic filler is treated with silane coupling agent.

4. The high-weatherable polycarbonate composite of claim 1, wherein, The components of the high-weather-resistant polycarbonate composite further include phosphorus flame retardant, 20% silicon content polydimethylsiloxane, sulfonate, and the weight ratio of the phosphorus flame retardant, 20% silicon content polydimethylsiloxane, and sulfonate is 5-12:2-8:0.5-3.

5. The high-weatherable polycarbonate composite of claim 4, wherein, The phosphorus flame retardant is selected from one or more combinations of resorcinol bis(diphenyl phosphate), bisphenol A bis(diphenyl phosphate) and triphenyl phosphate.

6. The high-weatherable polycarbonate composite of claim 4, wherein, The 20% silicon content polydimethylsiloxane is hydroxyl-terminated polydimethylsiloxane with a viscosity-average molecular weight of 5000-20000 g / mol.

7. The high weather-resistant polycarbonate composite material as described in claim 4, characterized in that, The sulfonate is selected from one or more of potassium perfluorobutyl sulfonate, sodium benzenesulfonate and sodium 2,4,5-trichlorobenzenesulfonate.

8. The high-weatherable polycarbonate composite of claim 1, wherein, The components of the high-weather-resistant polycarbonate composite further include styrene-acrylonitrile-glycidyl methacrylate copolymer; In the styrene-acrylonitrile-glycidyl methacrylate copolymer, the weight ratio of styrene, acrylonitrile and glycidyl methacrylate is (65-75):(20-30):(5-10), and the weight-average molecular weight is 80000-150000 g / mol.

9. The high-weatherable polycarbonate composite of claim 1, wherein, The components of the high-weather-resistant polycarbonate composite further include processing aids, which include lubricants and anti-dripping agents.

10. A process for the production of the high weatherable polycarbonate composite material according to any one of claims 1 to 9, characterized in that, The steps include: The polycarbonate and styrene-acrylonitrile-glycidyl methacrylate copolymer are dried, then mixed with phosphorus flame retardant, 20% silicon content polydimethylsiloxane, sulfonate, weather-resistant stabilizing system and nano-inorganic filler to obtain a premix, and the premix is melt blended and extruded at 180-275°C to obtain a high-weather-resistant polycarbonate composite.

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