Fluoride-free halogen-free flame-retardant polycarbonate material as well as preparation method and application thereof

Abstract

The invention relates to the technical field of high polymer materials, and particularly discloses a fluoride-free halogen-free flame-retardant polycarbonate material and a preparation method and application thereof.The fluoride-free halogen-free flame-retardant polycarbonate material is prepared from, by weight, 70-90 parts of polycarbonate resin, 8-15 parts of phosphorus-nitrogen flame retardant and 3-8 parts of silicon flame-retardant synergist, the composite material is prepared from the following raw materials in parts by weight: 20-30 parts of polypropylene, 2-5 parts of nano reinforcing filler, 0.1-0.5 part of hindered phenol antioxidant, 0.1-0.5 part of phosphite ester antioxidant and 0.1-0.5 part of pentaerythritol stearate. Through the synergistic effect of the composite flame-retardant system and the nanofiller, high flame retardance (UL94 V-0 level, 1.5 mm thickness), high heat resistance (the heat distortion temperature is greater than or equal to 130 DEG C) and excellent mechanical property are realized, the control is easy, the processing is stable, good balance of flame retardance and mechanical property is achieved on the premise of environmental protection, and the composite flame-retardant material is suitable for the fields of high-end household appliances and consumer electronics.

Description

Technical Field

[0001] This invention relates to the field of polymer materials technology, and in particular to a fluorine-free and halogen-free flame-retardant polycarbonate material, its preparation method, and its application. Background Technology

[0002] Polycarbonate (PC), one of the five major general-purpose engineering plastics, is renowned for its excellent optical transparency, outstanding impact resistance, good dimensional stability, excellent heat resistance, and superior dielectric properties. This material not only possesses low water absorption and is non-toxic and environmentally friendly, but also exhibits excellent low-temperature impact resistance and creep resistance. Currently, PC materials are increasingly widely used in electronics, automotive manufacturing, medical devices, building decoration, and safety protection. Simultaneously, PC materials are also demonstrating enormous application potential in high-tech industries such as military aerospace, information technology, and fiber optic communications.

[0003] It is worth noting that although PC materials achieve a V-2 rating in the UL-94 test and have a limiting oxygen index (LOI) of approximately 25%, indicating certain flame-retardant properties, they still fall short of the higher requirements for flame-retardant performance in fields such as electronics and electrical engineering. Furthermore, molten drips generated during PC combustion can trigger secondary combustion; therefore, in practical applications, it is often necessary to add both flame retardants and anti-dripping agents to improve fire safety. In the PC material field, commonly used flame retardants such as potassium perfluorobutyl sulfonate (PFBS) and anti-dripping agents such as polytetrafluoroethylene (PTFE) are both classified as restricted substances, posing new challenges to the flame-retardant modification of PC materials.

[0004] Existing halogen-free flame retardant technologies face the following challenges: 1. Insufficient flame retardant efficiency: For example, a low internal stress fluorine-free flame retardant polycarbonate material disclosed in Chinese patent CN117511167A uses oxidized polyethylene wax and can only achieve V-0 rating at a thickness of 1.5mm, which cannot meet the requirements of thin-walled parts. 2. Deterioration of mechanical properties: For example, Chinese patent CN118834513B discloses a halogen-free flame-retardant high-strength polycarbonate composite material, which uses a siloxane flame retardant, resulting in a 30-50% decrease in impact strength; 3. Poor thermal stability: For example, Chinese patent CN117567852A discloses a halogen-free flame-retardant modified polycarbonate anti-acetic acid metal inlay injection molded part. This material uses phosphorus-based flame retardants, which are prone to hydrolysis in humid and hot environments, resulting in significant strength reduction. 4. Complex process: Some solutions require multiple modification steps or high-cost nanofillers, making them difficult to industrialize. Summary of the Invention

[0005] Based on this, the purpose of this invention is to provide a fluorine-free and halogen-free flame-retardant polycarbonate material, its preparation method and application. Through the synergistic effect of the phosphorus-nitrogen synergistic flame-retardant system and nanofillers, excellent flame retardancy is achieved while ensuring the mechanical properties of the material, which can be applied to the fields of home appliances and consumer electronics.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: This invention provides a fluorine-free and halogen-free flame-retardant polycarbonate material, which is prepared from the following components in parts by weight: 70-90 parts of polycarbonate resin, 8-15 parts of phosphorus-nitrogen flame retardant, 3-8 parts of silicon-based flame retardant synergist, 2-5 parts of nano-reinforcing filler, 0.1-0.5 parts of hindered phenolic antioxidant, 0.1-0.5 parts of phosphite antioxidant, and 0.1-0.5 parts of pentaerythritol stearate.

[0007] As a further improvement of the above-mentioned solution of the present invention, the phosphorus-nitrogen flame retardant is composed of aluminum hypophosphite and melamine cyanurate in a mass ratio of (1-3):1; in the phosphorus-nitrogen flame retardant, the particle size of aluminum hypophosphite is ≤10μm and the purity of melamine cyanurate is ≥99%.

[0008] As a further improvement of the above-mentioned solution of the present invention, the silicon-based flame retardant synergist is a compound of phenylsilsesquioxane and polysiloxane in a mass ratio of 1:(1-3); in the silicon-based flame retardant synergist, the viscosity of the polysiloxane is 3000-10000cp.

[0009] As a further improvement to the above-mentioned scheme of the present invention, the nano-reinforcing filler is at least one of surface-modified nano-silica, surface-modified nano-kaolin, hydroxylated boron nitride, surface-modified nano-potassium titanate whiskers, and nano-silicon carbide, and the particle size of the nano-reinforcing filler is 20-100 nm.

[0010] As a further improvement to the above-mentioned solution of the present invention, the polycarbonate resin has a melt index of 8-15 g / 10 min at 300℃ / 1.2 kg, preferably a linear aromatic polycarbonate with a melt index of 8-15 g / 10 min (300℃ / 1.2 kg), preferably Mitsubishi E2000 or Covestro Makrolon 2805.

[0011] The hindered phenolic antioxidant is β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate octadecyl ester; the phosphite antioxidant is bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphate. Preferably, the hindered phenolic antioxidant is BASF's Irganox 1076 or Jinhaiyabao AT-76; the phosphite antioxidant is preferably BASF's Irganox 168 or Jinhaiyabao AT-168; and the pentaerythritol stearate is preferably PETS-HS (Italy or Germany).

[0012] The present invention also provides a method for preparing the fluorine-free and halogen-free flame-retardant polycarbonate material as described above, which includes the following steps: The polycarbonate resin, phosphorus-nitrogen flame retardant, silicone flame retardant synergist, nano-reinforcing filler, hindered phenolic antioxidant, phosphite antioxidant, and pentaerythritol stearate were dried separately. Phosphorus-nitrogen flame retardant, silicon-based flame retardant synergist, nano-reinforcing filler, hindered phenolic antioxidant, phosphite antioxidant, and pentaerythritol stearate are premixed in proportion; then polycarbonate resin is added in proportion for final mixing, fed into a twin-screw extruder, melted, extruded, and granulated to obtain fluorine-free and halogen-free flame-retardant polycarbonate material.

[0013] As a further improvement to the above-mentioned solution of the present invention, the polycarbonate resin is vacuum dried in a vacuum oven at 100-120°C for 4-6 hours until the moisture content of the polycarbonate resin is ≤0.02%; the phosphorus-nitrogen flame retardant, silicon-based flame retardant synergist, nano-reinforcing filler, hindered phenolic antioxidant, phosphite antioxidant, and pentaerythritol stearate are dried in a forced-air drying oven at 80-100°C for 2-4 hours.

[0014] As a further improvement to the above-mentioned solution of the present invention, the premixing speed is 600-900 r / min and the mixing time is 5-10 min; the final mixing speed is 800-1200 r / min and the mixing time is 5-10 min.

[0015] As a further improvement to the above-mentioned solution of the present invention, the temperatures of each zone of the twin-screw extruder are as follows: Zone 1 240-260℃, Zone 2 250-270℃, Zone 3 260-280℃, Zone 4 270-280℃, and Die head 270-290℃; the screw speed is 200-400 rpm; the screw length-to-diameter ratio (L / D) is 36-44; the pressure control is: Die head pressure 5-8 MPa, with a fluctuation range ≤ ±2 MPa; the feeding rate is 10-20 kg / h; the melting process adopts gradient heating control, with a temperature fluctuation range ≤ ±5℃, and the die head pressure is controlled at 5-8 MPa. The screw element configuration of the twin-screw extruder includes: 3-5 kneading blocks, the length of which is 1.5-2 times the screw diameter; and 2-3 reverse thread elements located at the junction of the melting section and the mixing section, with a thread lead of 0.8-1.3 times the screw diameter.

[0016] The present invention also provides an application of the fluorine-free and halogen-free flame-retardant polycarbonate material as described above in the field of home appliances and consumer electronics.

[0017] Unlike traditional flame-retardant modification of polycarbonate compositions, the flame-retardant system involved in this invention overcomes the limitations of traditional halogen-free flame-retardant technologies in selecting anti-dripping agents through a triple synergistic effect of gas-phase flame retardancy, condensed-phase flame retardancy, and nano-reinforcement. The specific mechanism of action is as follows: (1) Gas-phase flame retardancy: Melamine cyanurate (MCA) undergoes thermal decomposition in the temperature range of 240-300℃, producing NH3, H2O and nitrogen-containing free radicals. The released NH3 and H2O can effectively reduce the oxygen concentration in the combustion zone, while nitrogen-containing free radicals (such as ·NH2) significantly inhibit the spread of flame by capturing active free radicals (H·, HO·) in the combustion chain reaction.

[0018] (2) Condensed-phase flame retardancy: Aluminum hypophosphite (AHP) decomposes under high temperature conditions to form aluminum metaphosphate (Al(PO3)3) and polyphosphoric acid. The generated polyphosphoric acid can promote the dehydration of polycarbonate to form carbon, while the cage structure of phenylsilsesquioxane (POSS) is transformed into a three-dimensional network silica framework at 500-600℃, forming a "ceramic-carbon" composite structure (thickness > 100 μm) with the carbon layer. This composite layer has the following characteristics: 1. Thermal insulation: Thermal conductivity ≤0.15 W / (m·K) (ASTM E1461), which is 40% lower than that of pure carbon layer; 2. Antioxidant: The silicon-oxygen network structure inhibits the oxidative decomposition of the carbon layer at high temperatures (carbon residue ≥25% at 800℃). 3. Anti-dripping: The melt strength is increased to 1200 Pa·s (280℃, 1000s⁻¹), effectively eliminating dripping.

[0019] (3) Nano-reinforcement mechanism: Surface-modified nano-silica (20-50nm), kaolin (50-100nm), and hydroxylated boron nitride (particle size 20-50nm) enhance flame retardant efficiency through the following pathways: 1. Carbon layer reinforcement: Nanoparticles are embedded in the pores of the carbon layer, increasing the density of the carbon layer; 2. Free radical adsorption: The hydroxyl groups on the surface of the nanofiller combine with free radicals, prolonging the quenching time of the free radicals; 3. Thermal buffering: The high specific surface area of ​​the nanoparticles absorbs the heat of combustion, thus delaying the thermal degradation of the matrix.

[0020] Through the synergistic effect of the above material selection and mechanism, the material was made fluorine-free while maintaining excellent flame retardant properties.

[0021] This invention maintains good mechanical properties through interface optimization. A silane coupling agent (KH-550) is used to treat the surface of the nanofiller, forming a chemically bonded interface of "filler-coupling agent-matrix". The methoxy group of the silane hydrolyzes to generate Si-OH, which undergoes a condensation reaction with the hydroxyl groups on the filler surface, significantly enhancing stress transfer and thus achieving better toughening properties.

[0022] This invention also achieves precise control of melt rheological behavior through the synergistic design of the gradient temperature field and screw elements. This is because the combination of the kneading block and the anti-threading element allows the shear rate to be controlled within 3000-5000 s. -1 This avoids excessive shear that could lead to molecular chain breakage. The composition exhibits a uniform molecular weight distribution, good molecular chain strength and melt strength, playing a crucial role in maintaining mechanical properties and anti-dripping properties.

[0023] The antioxidant used in this invention is β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate octadecyl ester, which exhibits excellent thermal stability during the mixing of polycarbonate blends. The hindered piperidine groups contained in this antioxidant not only provide antioxidant effects but also enhance the colorability of the copolymer. Bis(2,6-di-tert-butyl-4-methylphenyl) pentaerythritol diphosphate has a high melting point of 239°C and a thermal decomposition temperature exceeding 350°C, exhibiting excellent heat resistance and hydrolysis resistance. This substance provides excellent color stability and melt stability when rapidly mixing modified polycarbonate materials, effectively preventing thermal degradation of polycarbonate, flame retardants, and other small molecule additives during high-temperature processing, and inhibiting long-term thermo-oxidative discoloration. Furthermore, this antioxidant also imparts color stability to the material in a nitrogen oxide (NOx) gas environment, avoiding the problem of discoloration caused by gas fumes.

[0024] The pentaerythritol stearate in this invention has a dual effect of improving the material's release properties and thermal stability. When used alone as a lubricant, it can significantly reduce the shear force exerted by the screw on the material, while also reducing the performance damage suffered by the material during physical shearing.

[0025] Compared with the prior art, the present invention has the following beneficial effects: This invention ingeniously combines phosphorus-nitrogen flame retardants, silicon-based flame retardant synergists, and surface-modified nano-reinforcing fillers to achieve blend modification of polycarbonate. This unique formulation not only achieves a dual flame retardant mechanism of both gas-phase and condensed-phase flame retardancy, but also realizes a triple synergistic effect through the addition of surface-modified nano-reinforcing fillers. This triple synergistic effect effectively overcomes the limitations of traditional halogen-free flame retardant technology in the selection of anti-dripping agents, significantly improving the flame retardant performance of the material without using fluorinated substances. Simultaneously, this invention also ensures improved processing performance, maintaining good mechanical properties while enhancing flame retardant performance. In addition to the aforementioned blend modification strategy of phosphorus-nitrogen flame retardants, silicon-based flame retardant synergists, and surface-modified nano-reinforcing fillers, this invention further stabilizes and enhances these modified properties through interface optimization technology, precise control of the gradient temperature field, and synergistic design of screw components. These combined measures work together to ensure that polycarbonate materials can still achieve excellent flame retardancy and mechanical properties without the use of fluorine-containing components, providing new possibilities for the application of polycarbonate materials.

[0026] This invention achieves high flame retardancy (UL94 V-0 rating, 1.5mm thickness), high heat resistance (heat distortion temperature ≥130℃), and excellent mechanical properties through the synergistic effect of a composite flame retardant system and nanofillers.

[0027] The method for preparing fluorine-free and halogen-free flame-retardant polycarbonate materials provided by this invention is easy to control and has stable processing. It achieves a good balance between flame retardant performance and mechanical properties under the premise of environmental protection and can be used in high-end home appliances and consumer electronics. Attached Figure Description

[0028] Figure 1 This is a flowchart of the preparation method of the fluorine-free and halogen-free flame-retardant polycarbonate material of the present invention. Detailed Implementation

[0029] To facilitate understanding of the present invention, a more comprehensive description will be given below with reference to specific embodiments. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the disclosure of the present invention.

[0030] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0031] The specific information of the raw materials used in the following examples and comparative examples is as follows: The polycarbonate resin, a linear aromatic polycarbonate with a melt index of 10 g / 10 min at 300℃ / 1.2 kg, is selected from Covestro Makrolon 2805; Aluminum hypophosphite, sourced from Guangzhou Rongda Chemical Co., Ltd.; Melamine cyanurate, selected from Henan Weitixi Chemical Technology Co., Ltd.; Phenylsilsesquioxane, selected from Forsmann Technology (Beijing) Co., Ltd.; Polysiloxane, selected from Guangzhou Fantai New Materials Technology Co., Ltd.; Surface-modified nano-silica: self-made, prepared by means of: drying nano-silica at 105℃ for 5h, sieving and grinding, preparing a nano-silica suspension with an initial concentration of 15%, and adding 3wt% (relative to the nano-silica suspension) of KH-550 anhydrous ethanol solution. The mixture is stirred in a magnetically stirred reaction bath at 95℃ and a stirring rate of 1000 r / min for 25 min. The resulting mixed solution is filtered while hot, and the resulting filter cake is dried at 105℃ for 10h, followed by sieving and grinding. The sieved powder is dried at 105℃ for 3h and then allowed to stand in air for 48h to obtain surface-modified nano-silica. The nano-silica is selected from Shanghai Aladdin Biochemical Technology Co., Ltd.; KH-550 is selected from Shandong Fengpan New Materials Co., Ltd. Surface-modified nano-kaolin: self-made, prepared by the following method: nano-kaolin was dried at 105℃ for 6 hours, then sieved and ground. A nano-kaolin suspension with an initial concentration of 15% was prepared, along with a 3wt% KH-550 anhydrous ethanol solution (relative to the nano-silica suspension). The mixture was stirred in a magnetically stirred reaction bath at 95℃ and a stirring rate of 1000 r / min for 25 minutes. The resulting mixed solution was filtered while hot, and the resulting filter cake was dried at 105℃ for 10 hours, followed by sieving and grinding. The sieved powder was dried at 105℃ for 4 hours and then allowed to stand in air for 48 hours to obtain the surface-modified nano-kaolin. The nano-kaolin was selected from Shanghai Yuanye Biotechnology Co., Ltd., and KH-550 was selected from Shandong Fengpan New Materials Co., Ltd. Surface-modified potassium titanate nano whiskers: self-made, prepared by means of: drying potassium titanate nano whiskers at 105℃ for 6h, sieving and grinding, preparing a potassium titanate nano whisker suspension with an initial concentration of 15%, and a KH-550 anhydrous ethanol solution with a doping amount of 3wt% (relative to the nano silica suspension), and stirring in a magnetically stirred reaction bath at 95℃ and a stirring rate of 1000 r / min for 25 min, filtering the resulting mixed solution while hot, and drying the resulting filter cake at 105℃ for 10h, followed by sieving and grinding; drying the sieved powder at 105℃ for 4h, and then allowing it to stand in air for 48h to obtain surface-modified potassium titanate nano whiskers; wherein the potassium titanate nano whiskers are selected from Otsuka Chemicals, Japan, and KH-550 is selected from Shandong Fengpan New Materials Co., Ltd. Nano-silicon carbide, selected from Shanghai Fantanxi Biochemical Technology Co., Ltd.; Decabromodiphenyl ethane, selected from Taizhou Baili Chemical Co., Ltd.; Antimony trioxide, Guangdong Yuxing Flame Retardant New Materials Co., Ltd. The hindered phenolic antioxidant is β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate octadecyl ester, selected from BASF GmbH, Germany; The phosphite antioxidant is bis(2,6-di-tert-butyl-4-methylphenyl) pentaerythritol diphosphate, selected from BASF GmbH, Germany; Pentaerythritol stearate, selected from Zhaoqing Sendeli Chemical Industry Co., Ltd.

[0032] The above-mentioned raw materials are only for illustrating the source and composition of the reagents used in the experiments of this invention, so as to fully disclose them, and do not imply that the invention cannot be achieved by using other similar reagents or reagents provided by other suppliers.

[0033] Unless otherwise specified, the reagents, methods and equipment used in this invention are all conventional reagents, methods and equipment in this technical field.

[0034] Example 1 This embodiment proposes a fluorine-free and halogen-free flame-retardant polycarbonate material, which comprises the following components in parts by weight: 84 parts polycarbonate resin, 6 parts aluminum hypophosphite, 3 parts melamine cyanurate, 2 parts phenylsilsesquioxane, 2 parts polysiloxane, 1.5 parts surface-modified nano silica, 1.5 parts surface-modified nano kaolin, 0.1 parts hindered phenolic antioxidant, 0.1 parts phosphite antioxidant, and 0.3 parts pentaerythritol stearate.

[0035] The fluorine-free and halogen-free flame-retardant polycarbonate material in this embodiment is prepared according to the following steps: S1. Place polycarbonate resin in a vacuum oven and dry at 100℃ for 5 hours; place aluminum hypophosphite, melamine cyanurate, phenyl silsesquioxane, polysiloxane, surface-modified nano silica, surface-modified nano kaolin, hindered phenolic antioxidant, phosphite antioxidant, and pentaerythritol stearate in a forced-air drying oven and dry at 80℃ for 2 hours.

[0036] S2. Add the dried aluminum hypophosphite, melamine cyanurate, phenyl silsesquioxane, polysiloxane, surface-modified nano silica, surface-modified nano kaolin, hindered phenolic antioxidant, phosphite antioxidant, and pentaerythritol stearate from step S1 into a high-speed mixer according to the proportion, and mix at 700 r / min for 7 min.

[0037] S3. Add the vacuum-dried polycarbonate from step S1 into the high-speed mixer of step S2 according to the proportion, and continue mixing at a speed of 900 r / min for 8 min.

[0038] S4. The mixture obtained in step S3 is fed uniformly into a twin-screw extruder via a feed hopper, and then melt-extruded and granulated in the twin-screw extruder to obtain a fluorine-free and halogen-free flame-retardant polycarbonate material. The granulation process parameters include: zone 1 240℃, zone 2 250℃, zone 3 260℃, zone 4 270℃, zone 5 265℃, die head 270℃, and screw speed 300 rpm. The twin-screw extruder has a single-thread screw, a length-to-diameter ratio (L / D) of 40, pressure control: die head pressure 6 MPa, fluctuation range ≤ ±2 MPa, and a feed rate of 18 kg / h. The twin-screw extruder's screw element configuration includes: 3 kneading blocks and 2 reverse thread elements. The length of the kneading blocks is 1.5 times the screw diameter, and the reverse thread elements are located at the junction of the melting and mixing sections, with a thread lead of 1 time the screw diameter.

[0039] Example 2 This embodiment proposes a fluorine-free and halogen-free flame-retardant polycarbonate material, which comprises the following raw materials in parts by weight: 81 parts polycarbonate resin, 9 parts aluminum hypophosphite, 3 parts melamine cyanurate, 2 parts phenylsilsesquioxane, 2 parts polysiloxane, 1.5 parts surface-modified nano silica, 1.5 parts surface-modified nano kaolin, 0.1 parts hindered phenolic antioxidant, 0.1 parts phosphite antioxidant, and 0.3 parts pentaerythritol stearate.

[0040] The fluorine-free and halogen-free flame-retardant polycarbonate material in this embodiment is prepared according to the following steps: S1. Place polycarbonate resin in a vacuum oven and dry at 100℃ for 5 hours; place aluminum hypophosphite, melamine cyanurate, phenyl silsesquioxane, polysiloxane, surface-modified nano silica, surface-modified nano kaolin, hindered phenolic antioxidant, phosphite antioxidant, and pentaerythritol stearate in a forced-air drying oven and dry at 80℃ for 2 hours.

[0041] S2. Add the dried aluminum hypophosphite, melamine cyanurate, phenyl silsesquioxane, polysiloxane, surface-modified nano silica, surface-modified nano kaolin, hindered phenolic antioxidant, phosphite antioxidant, and pentaerythritol stearate from step S1 into a high-speed mixer according to the proportion, and mix at 700 r / min for 7 min.

[0042] S3. Add the vacuum-dried polycarbonate from step S1 into the high-speed mixer of step S2 according to the proportion, and continue mixing at a speed of 900 r / min for 8 min.

[0043] S4. The mixture obtained in step S3 is fed uniformly into a twin-screw extruder via a feed hopper, and then melt-extruded and granulated in the twin-screw extruder to obtain a fluorine-free and halogen-free flame-retardant polycarbonate material. The granulation process parameters include: zone 1 240℃, zone 2 250℃, zone 3 260℃, zone 4 270℃, zone 5 265℃, die head 270℃, and screw speed 300 rpm. The twin-screw extruder has a single-thread screw, a length-to-diameter ratio (L / D) of 40, pressure control: die head pressure 6 MPa, fluctuation range ≤ ±2 MPa, and a feed rate of 18 kg / h. The twin-screw extruder's screw element configuration includes: 3 kneading blocks and 2 reverse thread elements. The length of the kneading blocks is 1.5 times the screw diameter, and the reverse thread elements are located at the junction of the melting and mixing sections, with a thread lead of 1 time the screw diameter.

[0044] Example 3 This embodiment proposes a fluorine-free and halogen-free flame-retardant polycarbonate material, which comprises the following components in parts by weight: 84 parts polycarbonate resin, 6 parts aluminum hypophosphite, 3 parts melamine cyanurate, 2 parts phenylsilsesquioxane, 2 parts polysiloxane, 1.5 parts surface-modified nano silica, 1.5 parts hydroxylated boron nitride, 0.1 parts hindered phenolic antioxidant, 0.1 parts phosphite antioxidant, and 0.3 parts pentaerythritol stearate.

[0045] The fluorine-free and halogen-free flame-retardant polycarbonate material in this embodiment is prepared according to the following steps: S1. Place polycarbonate resin in a vacuum oven and dry at 100°C for 5 hours; place aluminum hypophosphite, melamine cyanurate, phenyl silsesquioxane, polysiloxane, surface-modified nano silica, hydroxylated boron nitride, hindered phenolic antioxidants, phosphite antioxidants, and pentaerythritol stearate in a forced-air drying oven and dry at 80°C for 2 hours.

[0046] S2. Add the dried aluminum hypophosphite, melamine cyanurate, phenyl silsesquioxane, polysiloxane, surface-modified nano silica, hydroxylated boron nitride, hindered phenolic antioxidant, phosphite antioxidant, and pentaerythritol stearate to a high-speed mixer according to the proportion, and mix at 700 r / min for 7 min.

[0047] S3. Add the vacuum-dried polycarbonate from step S1 into the high-speed mixer of step S2 according to the proportion, and continue mixing at a speed of 900 r / min for 8 min.

[0048] S4. The mixture obtained in step S3 is fed uniformly into a twin-screw extruder via a feed hopper, and then melt-extruded and granulated in the twin-screw extruder to obtain a fluorine-free and halogen-free flame-retardant polycarbonate material. The granulation process parameters include: zone 1 240℃, zone 2 250℃, zone 3 260℃, zone 4 270℃, zone 5 265℃, die head 270℃, and screw speed 300 rpm. The twin-screw extruder has a single-thread screw, a length-to-diameter ratio (L / D) of 40, pressure control: die head pressure 6 MPa, fluctuation range ≤ ±2 MPa, and a feed rate of 18 kg / h. The twin-screw extruder's screw element configuration includes: 3 kneading blocks and 2 reverse thread elements. The length of the kneading blocks is 1.5 times the screw diameter, and the reverse thread elements are located at the junction of the melting and mixing sections, with a thread lead of 1 time the screw diameter.

[0049] Example 4 This embodiment proposes a fluorine-free and halogen-free flame-retardant polycarbonate material, which comprises the following components in parts by weight: 84 parts polycarbonate resin, 6 parts aluminum hypophosphite, 3 parts melamine cyanurate, 1 part phenylsilsesquioxane, 3 parts polysiloxane, 1.5 parts surface-modified nano silica, 1.5 parts surface-modified nano kaolin, 0.1 parts hindered phenolic antioxidant, 0.1 parts phosphite antioxidant, and 0.3 parts pentaerythritol stearate.

[0050] The fluorine-free and halogen-free flame-retardant polycarbonate material in this embodiment is prepared according to the following steps: S1. Place polycarbonate resin in a vacuum oven and dry at 100℃ for 5 hours; place aluminum hypophosphite, melamine cyanurate, phenyl silsesquioxane, polysiloxane, surface-modified nano silica, surface-modified nano kaolin, hindered phenolic antioxidant, phosphite antioxidant, and pentaerythritol stearate in a forced-air drying oven and dry at 80℃ for 2 hours.

[0051] S2. Add the dried aluminum hypophosphite, melamine cyanurate, phenyl silsesquioxane, polysiloxane, surface-modified nano silica, surface-modified nano kaolin, hindered phenolic antioxidant, phosphite antioxidant, and pentaerythritol stearate from step S1 into a high-speed mixer according to the proportion, and mix at 700 r / min for 7 min.

[0052] S3. Add the vacuum-dried polycarbonate from step S1 into the high-speed mixer of step S2 according to the proportion, and continue mixing at a speed of 900 r / min for 8 min.

[0053] S4. The mixture obtained in step S3 is fed uniformly into a twin-screw extruder via a feed hopper, and then melt-extruded and granulated in the twin-screw extruder to obtain a fluorine-free and halogen-free flame-retardant polycarbonate material. The granulation process parameters include: zone 1 240℃, zone 2 250℃, zone 3 260℃, zone 4 270℃, zone 5 265℃, die head 270℃, and screw speed 300 rpm. The twin-screw extruder has a single-thread screw, a length-to-diameter ratio (L / D) of 40, pressure control: die head pressure 6 MPa, fluctuation range ≤ ±2 MPa, and a feed rate of 18 kg / h. The twin-screw extruder's screw element configuration includes: 3 kneading blocks and 2 reverse thread elements. The length of the kneading blocks is 1.5 times the screw diameter, and the reverse thread elements are located at the junction of the melting and mixing sections, with a thread lead of 1 time the screw diameter.

[0054] Example 5 This embodiment proposes a fluorine-free and halogen-free flame-retardant polycarbonate material, which comprises the following components in parts by weight: 84 parts polycarbonate resin, 6 parts aluminum hypophosphite, 3 parts melamine cyanurate, 2 parts phenylsilsesquioxane, 2 parts polysiloxane, 1.5 parts nano-silicon carbide, 1.5 parts hydroxylated boron nitride, 0.1 parts hindered phenolic antioxidant, 0.1 parts phosphite antioxidant, and 0.3 parts pentaerythritol stearate.

[0055] The fluorine-free and halogen-free flame-retardant polycarbonate material in this embodiment is prepared according to the following steps: S1. Place polycarbonate resin in a vacuum oven and dry at 100°C for 5 hours; place aluminum hypophosphite, melamine cyanurate, phenyl silsesquioxane, polysiloxane, nano silicon carbide, hydroxylated boron nitride, hindered phenolic antioxidants, phosphite antioxidants, and pentaerythritol stearate in a forced-air drying oven and dry at 80°C for 2 hours.

[0056] S2. Add the dried aluminum hypophosphite, melamine cyanurate, phenyl silsesquioxane, polysiloxane, nano silicon carbide, hydroxylated boron nitride, hindered phenolic antioxidant, phosphite antioxidant, and pentaerythritol stearate to a high-speed mixer according to the proportion, and mix at 700 r / min for 7 min.

[0057] S3. Add the vacuum-dried polycarbonate from step S1 into the high-speed mixer of step S2 according to the proportion, and continue mixing at a speed of 900 r / min for 8 min.

[0058] S4. The mixture obtained in step S3 is fed uniformly into a twin-screw extruder via a feed hopper, and then melt-extruded and granulated in the twin-screw extruder to obtain a fluorine-free and halogen-free flame-retardant polycarbonate material. The granulation process parameters include: zone 1 240℃, zone 2 250℃, zone 3 260℃, zone 4 270℃, zone 5 265℃, die head 270℃, and screw speed 300 rpm. The twin-screw extruder has a single-thread screw, a length-to-diameter ratio (L / D) of 40, pressure control: die head pressure 6 MPa, fluctuation range ≤ ±2 MPa, and a feed rate of 18 kg / h. The twin-screw extruder's screw element configuration includes: 3 kneading blocks and 2 reverse thread elements. The length of the kneading blocks is 1.5 times the screw diameter, and the reverse thread elements are located at the junction of the melting and mixing sections, with a thread lead of 1 time the screw diameter.

[0059] Example 6 This embodiment proposes a fluorine-free and halogen-free flame-retardant polycarbonate material, which comprises the following components in parts by weight: 84 parts polycarbonate resin, 6 parts aluminum hypophosphite, 3 parts melamine cyanurate, 2 parts phenylsilsesquioxane, 2 parts polysiloxane, 1.5 parts surface-modified nano silica, 1.5 parts surface-modified nano potassium titanate whiskers, 0.1 parts hindered phenolic antioxidant, 0.1 parts phosphite antioxidant, and 0.3 parts pentaerythritol stearate.

[0060] The fluorine-free and halogen-free flame-retardant polycarbonate material in this embodiment is prepared according to the following steps: S1. Place polycarbonate resin in a vacuum oven and dry at 100℃ for 5 hours; place aluminum hypophosphite, melamine cyanurate, phenyl silsesquioxane, polysiloxane, surface-modified nano silica, surface-modified nano kaolin, hindered phenolic antioxidant, phosphite antioxidant, and pentaerythritol stearate in a forced-air drying oven and dry at 80℃ for 2 hours.

[0061] S2. Add the dried aluminum hypophosphite, melamine cyanurate, phenyl silsesquioxane, polysiloxane, surface-modified nano silica, surface-modified nano kaolin, hindered phenolic antioxidant, phosphite antioxidant, and pentaerythritol stearate from step S1 into a high-speed mixer according to the proportion, and mix at 700 r / min for 7 min.

[0062] S3. Add the vacuum-dried polycarbonate from step S1 into the high-speed mixer of step S2 according to the proportion, and continue mixing at a speed of 900 r / min for 8 min.

[0063] S4. The mixture obtained in step S3 is fed uniformly into a twin-screw extruder via a feed hopper, and then melt-extruded and granulated in the twin-screw extruder to obtain a fluorine-free and halogen-free flame-retardant polycarbonate material. The granulation process parameters include: zone 1 255℃, zone 2 265℃, zone 3 275℃, zone 4 280℃, zone 5 285℃, die head 290℃, and screw speed 400 rpm. The twin-screw extruder has a single-thread screw shape, a screw length-to-diameter ratio (L / D) of 40, pressure control: die head pressure 6 MPa, fluctuation range ≤ ±2 MPa, and a feed rate of 18 kg / h. The twin-screw extruder's screw element configuration includes: 3 kneading blocks and 2 reverse thread elements. The length of the kneading blocks is 1.5 times the screw diameter, and the reverse thread elements are located at the junction of the melting section and the mixing section, with a thread lead of 1.3 times the screw diameter.

[0064] Comparative Example 1 The present comparative example presents a fluorine-free and halogen-free flame-retardant polycarbonate material comprising the following components in parts by weight: 84 parts polycarbonate resin, 12 parts decabromodiphenyl ethane, 4 parts antimony trioxide, 0.1 parts hindered phenolic antioxidant, 0.1 parts phosphite antioxidant, and 0.3 parts pentaerythritol stearate.

[0065] The fluorine-free and halogen-free flame-retardant polycarbonate material of this comparative example was prepared according to the following steps: S1. Place polycarbonate resin in a vacuum oven and dry at 100°C for 5 hours; place decabromodiphenyl ethane, antimony trioxide, hindered phenolic antioxidants, phosphite antioxidants, and pentaerythritol stearate in a forced-air drying oven and dry at 80°C for 3 hours.

[0066] S2. Add the decabromodiphenyl ethane, antimony trioxide, hindered phenolic antioxidant, phosphite antioxidant, and pentaerythritol stearate that have been dried in step S1 to a high-speed mixer in proportion, and mix at a speed of 700 r / min for 7 min.

[0067] S3. Add the vacuum-dried polycarbonate from step S1 into the high-speed mixer of step S2 according to the proportion, and continue mixing at a speed of 900 r / min for 8 min.

[0068] S4. The mixture obtained in step S3 is fed uniformly into a twin-screw extruder via a feed hopper, and then melt-extruded and granulated in the twin-screw extruder to obtain a fluorine-free and halogen-free flame-retardant polycarbonate material. The granulation process parameters include: zone 1 240℃, zone 2 250℃, zone 3 260℃, zone 4 270℃, zone 5 265℃, die head 270℃, and screw speed 300 rpm. The twin-screw extruder has a single-thread screw, a length-to-diameter ratio (L / D) of 40, pressure control: die head pressure 6 MPa, fluctuation range ≤ ±2 MPa, and a feed rate of 18 kg / h. The twin-screw extruder's screw element configuration includes: 3 kneading blocks and 2 reverse thread elements. The length of the kneading blocks is 1.5 times the screw diameter, and the reverse thread elements are located at the junction of the melting and mixing sections, with a thread lead of 1 time the screw diameter.

[0069] Comparative Example 2 This comparative example presents a fluorine-free and halogen-free flame-retardant polycarbonate material, which comprises the following components in parts by weight: 85 parts polycarbonate resin, 9 parts aluminum hypophosphite, 0.1 parts hindered phenolic antioxidant, 0.1 parts phosphite antioxidant, and 0.3 parts pentaerythritol stearate.

[0070] The fluorine-free and halogen-free flame-retardant polycarbonate material of this comparative example was prepared according to the following steps: S1. Place the polycarbonate resin in a vacuum oven and dry it at 100°C for 5 hours; place the aluminum hypophosphite, hindered phenolic antioxidant, phosphite antioxidant, and pentaerythritol stearate in a forced-air drying oven and dry them at 80°C for 2 hours.

[0071] S2. Add the dried aluminum hypophosphite, hindered phenolic antioxidant, phosphite antioxidant, and pentaerythritol stearate from step S1 to a high-speed mixer in proportion, and mix at 700 r / min for 7 min.

[0072] S3. Add the vacuum-dried polycarbonate from step S1 into the high-speed mixer of step S2 according to the proportion, and continue mixing at a speed of 900 r / min for 8 min.

[0073] S4. The mixture obtained in step S3 is fed uniformly into a twin-screw extruder via a feed hopper, and then melt-extruded and granulated in the twin-screw extruder to obtain a fluorine-free and halogen-free flame-retardant polycarbonate material. The granulation process parameters include: zone 1 240℃, zone 2 250℃, zone 3 260℃, zone 4 270℃, zone 5 265℃, die head 270℃, and screw speed 300 rpm. The twin-screw extruder has a single-thread screw, a length-to-diameter ratio (L / D) of 40, pressure control: die head pressure 6 MPa, fluctuation range ≤ ±2 MPa, and a feed rate of 18 kg / h. The twin-screw extruder's screw element configuration includes: 3 kneading blocks and 2 reverse thread elements. The length of the kneading blocks is 1.5 times the screw diameter, and the reverse thread elements are located at the junction of the melting and mixing sections, with a thread lead of 1 time the screw diameter.

[0074] Comparative Example 3 This comparative example presents a fluorine-free and halogen-free flame-retardant polycarbonate material, comprising the following components in parts by weight: 88 parts polycarbonate resin, 6 parts aluminum hypophosphite, 3 parts melamine cyanurate, 1.5 parts surface-modified nano silica, 1.5 parts surface-modified nano kaolin, 0.1 parts hindered phenolic antioxidant, 0.1 parts phosphite antioxidant, and 0.3 parts pentaerythritol stearate.

[0075] The fluorine-free and halogen-free flame-retardant polycarbonate material of this comparative example was prepared according to the following steps: S1. Place polycarbonate resin in a vacuum oven and dry at 100℃ for 5 hours; place aluminum hypophosphite, melamine cyanurate, surface-modified nano silica, surface-modified nano kaolin, hindered phenolic antioxidants, phosphite antioxidants, and pentaerythritol stearate in a forced-air drying oven and dry at 80℃ for 2 hours.

[0076] S2. Add the dried aluminum hypophosphite, melamine cyanurate, surface-modified nano silica, surface-modified nano kaolin, hindered phenolic antioxidant, phosphite antioxidant, and pentaerythritol stearate from step S1 into a high-speed mixer according to the proportion, and mix at 700 r / min for 7 min.

[0077] S3. Add the vacuum-dried polycarbonate from step S1 into the high-speed mixer of step S2 according to the proportion, and continue mixing at a speed of 900 r / min for 8 min.

[0078] S4. The mixture obtained in step S3 is fed uniformly into a twin-screw extruder via a feed hopper, and then melt-extruded and granulated in the twin-screw extruder to obtain a fluorine-free and halogen-free flame-retardant polycarbonate material. The granulation process parameters include: zone 1 240℃, zone 2 250℃, zone 3 260℃, zone 4 270℃, zone 5 265℃, die head 270℃, and screw speed 300 rpm. The twin-screw extruder has a single-thread screw, a length-to-diameter ratio (L / D) of 40, pressure control: die head pressure 6 MPa, fluctuation range ≤ ±2 MPa, and a feed rate of 18 kg / h. The twin-screw extruder's screw element configuration includes: 3 kneading blocks and 2 reverse thread elements. The length of the kneading blocks is 1.5 times the screw diameter, and the reverse thread elements are located at the junction of the melting and mixing sections, with a thread lead of 1 time the screw diameter.

[0079] Comparative Example 4 This comparative example presents a fluorine-free and halogen-free flame-retardant polycarbonate material, comprising the following components in parts by weight: 79 parts polycarbonate resin, 6 parts aluminum hypophosphite, 3 parts melamine cyanurate, 2 parts phenylsilsesquioxane, 2 parts polysiloxane, 4 parts surface-modified nano silica, 4 parts surface-modified nano kaolin, 0.1 parts hindered phenolic antioxidant, 0.1 parts phosphite antioxidant, and 0.3 parts pentaerythritol stearate.

[0080] The fluorine-free and halogen-free flame-retardant polycarbonate material of this comparative example was prepared according to the following steps: S1. Place polycarbonate resin in a vacuum oven and dry at 100℃ for 5 hours; place aluminum hypophosphite, melamine cyanurate, phenyl silsesquioxane, polysiloxane, surface-modified nano silica, surface-modified nano kaolin, hindered phenolic antioxidant, phosphite antioxidant, and pentaerythritol stearate in a forced-air drying oven and dry at 80℃ for 2 hours.

[0081] S2. Add the dried aluminum hypophosphite, melamine cyanurate, phenyl silsesquioxane, polysiloxane, surface-modified nano silica, surface-modified nano kaolin, hindered phenolic antioxidant, phosphite antioxidant, and pentaerythritol stearate from step S1 into a high-speed mixer according to the proportion, and mix at 700 r / min for 7 min.

[0082] S3. Add the vacuum-dried polycarbonate from step S1 into the high-speed mixer of step S2 according to the proportion, and continue mixing at a speed of 900 r / min for 8 min.

[0083] S4. The mixture obtained in step S3 is fed uniformly into a twin-screw extruder via a feed hopper, and then melt-extruded and granulated in the twin-screw extruder to obtain a fluorine-free and halogen-free flame-retardant polycarbonate material. The granulation process parameters include: zone 1 240℃, zone 2 250℃, zone 3 260℃, zone 4 270℃, zone 5 265℃, die head 270℃, and screw speed 300 rpm. The twin-screw extruder has a single-thread screw, a length-to-diameter ratio (L / D) of 40, pressure control: die head pressure 6 MPa, fluctuation range ≤ ±2 MPa, and a feed rate of 18 kg / h. The twin-screw extruder's screw element configuration includes: 3 kneading blocks and 2 reverse thread elements. The length of the kneading blocks is 1.5 times the screw diameter, and the reverse thread elements are located at the junction of the melting and mixing sections, with a thread lead of 1 time the screw diameter.

[0084] Comparative Example 5 This embodiment proposes a fluorine-free and halogen-free flame-retardant polycarbonate material, which comprises the following components in parts by weight: 84 parts polycarbonate resin, 6 parts aluminum hypophosphite, 3 parts melamine cyanurate, 2 parts phenylsilsesquioxane, 2 parts polysiloxane, 1.5 parts surface-modified nano silica, 1.5 parts surface-modified nano kaolin, 0.1 parts hindered phenolic antioxidant, 0.1 parts phosphite antioxidant, and 0.3 parts pentaerythritol stearate.

[0085] The fluorine-free and halogen-free flame-retardant polycarbonate material of this comparative example was prepared according to the following steps: S1. Place polycarbonate resin in a vacuum oven and dry at 100℃ for 5 hours; place aluminum hypophosphite, melamine cyanurate, phenyl silsesquioxane, polysiloxane, surface-modified nano silica, surface-modified nano kaolin, hindered phenolic antioxidant, phosphite antioxidant, and pentaerythritol stearate in a forced-air drying oven and dry at 80℃ for 2 hours.

[0086] S2. Add the dried aluminum hypophosphite, melamine cyanurate, phenyl silsesquioxane, polysiloxane, surface-modified nano silica, surface-modified nano kaolin, hindered phenolic antioxidant, phosphite antioxidant, and pentaerythritol stearate from step S1 into a high-speed mixer according to the proportion, and mix at 700 r / min for 7 min.

[0087] S3. Add the vacuum-dried polycarbonate from step S1 into the high-speed mixer of step S2 according to the proportion, and continue mixing at a speed of 900 r / min for 8 min.

[0088] S4. The mixture obtained in step S3 is fed uniformly into a twin-screw extruder via a feed hopper, and then melt-extruded and granulated in the twin-screw extruder to obtain a fluorine-free and halogen-free flame-retardant polycarbonate material. The granulation process parameters include: zone 1 270℃, zone 2 275℃, zone 3 280℃, zone 4 285℃, zone 5 290℃, die head 300℃, and screw speed 400 rpm. The twin-screw extruder has a single-thread screw shape, a screw length-to-diameter ratio (L / D) of 40, pressure control: die head pressure 6 MPa, fluctuation range ≤ ±2 MPa, and a feed rate of 18 kg / h. The twin-screw extruder's screw element configuration includes: 3 kneading blocks and 2 reverse thread elements. The length of the kneading blocks is 1.5 times the screw diameter, and the reverse thread elements are located at the junction of the melting section and the mixing section, with a thread lead of 1 time the screw diameter.

[0089] Comparative Example 6 This embodiment proposes a fluorine-free and halogen-free flame-retardant polycarbonate material, which comprises the following components in parts by weight: 84 parts polycarbonate resin, 7 parts phenylsilsesquioxane, 6 parts polysiloxane, 1.5 parts surface-modified nano silica, 1.5 parts surface-modified nano kaolin, 0.1 parts hindered phenolic antioxidant, 0.1 parts phosphite antioxidant, and 0.3 parts pentaerythritol stearate.

[0090] The fluorine-free and halogen-free flame-retardant polycarbonate material of this comparative example was prepared according to the following steps: S1. Place polycarbonate resin in a vacuum oven and dry at 100°C for 5 hours; place phenyl silsesquioxane, polysiloxane, surface-modified nano silica, surface-modified nano kaolin, hindered phenolic antioxidant, phosphite antioxidant, and pentaerythritol stearate in a forced-air drying oven and dry at 80°C for 2 hours.

[0091] S2. Add the dried phenyl silsesquioxane, polysiloxane, surface-modified nano silica, surface-modified nano kaolin, hindered phenolic antioxidant, phosphite antioxidant, and pentaerythritol stearate from step S1 into a high-speed mixer according to the proportion, and mix at 700 r / min for 7 min.

[0092] S3. Add the vacuum-dried polycarbonate from step S1 into the high-speed mixer of step S2 according to the proportion, and continue mixing at a speed of 900 r / min for 8 min.

[0093] S4. The mixture obtained in step S3 is fed into a twin-screw extruder at a uniform speed through a feed hopper, and then melt-extruded and granulated in the twin-screw extruder to obtain a fluorine-free and halogen-free flame-retardant polycarbonate material. The granulation process parameters include: zone 1 240℃, zone 2 250℃, zone 3 260℃, zone 4 270℃, zone 5 265℃, die head 270℃, and screw speed 300 rpm. The twin-screw extruder has a single-thread screw shape, a screw length-to-diameter ratio (L / D) of 40, pressure control: die head pressure 6 MPa, fluctuation range ≤ ±2 MPa, and a feed rate of 18 kg / h. The twin-screw extruder's screw element configuration includes: 3 kneading blocks and 2 reverse thread elements. The length of the kneading blocks is 1.5 times the screw diameter, and the reverse thread elements are located at the junction of the melting section and the mixing section, with a thread lead of 1 time the screw diameter.

[0094] Test case The polycarbonate compositions obtained in Examples 1-6 and Comparative Examples 1-6 were subjected to the following performance tests: Impact performance: Tested according to ISO 180 standard, sample size 80mm×10mm×4mm (V notch); Tensile strength: Tested according to ISO 527-2 standard, sample size 150mm×10mm×4mm; Bending strength: Tested according to ISO 178 standard, sample size 80mm×10mm×4mm; Heat distortion temperature: tested according to ISO 75-1 (1.8MPa) standard, sample size 80mm×10mm×4mm; Melt flow index: Tested according to ISO 1133 (300℃ / 1.2kg) standard. The sample is granular with a particle size of 3-4mm. Vertical flammability rating: Tested according to ASTM D3801 UL 94 standards, sample size 125mm×13mm×1.5mm.

[0095] The performance test results are shown in Tables 1 and 2.

[0096] Table 1. Performance overview of the halogen-free flame-retardant polycarbonate materials of the examples and comparative examples.

[0097] Table 2. Performance overview of the halogen-free flame-retardant polycarbonate materials of the examples and comparative examples.

[0098] Examples 1-6 involve adjusting the flame retardant, silicone-based flame retardant synergist, filler type, and process parameters. Observing the data in the table, it can be seen that Example 1 performs best in terms of flame retardant properties, with its UL94 V-0 rating (burning time of 27 seconds at a thickness of 1.5 mm) placing it in the upper-middle range of Examples 1-6. Although Example 4 shortened the burning time to 19 seconds by increasing the proportion of siloxane (phenylsilsesquioxane to polysiloxane mass ratio 1:3), its flowability (melt index 13.4 g / 10 min) was slightly inferior to Example 1. Example 5 had the lowest burning time, but its formulation, which combined boron nitride and silicon carbide, significantly increased costs (filler cost increased by 200%), limiting its industrial application. Example 6, due to the limitations of the extrusion process, achieved a melt index as high as 18.0 g / 10 min, making it suitable for high-speed injection molding, but the burning time was extended to 40 seconds, resulting in a significant decrease in flame retardant efficiency. Overall, Example 1 achieved the best balance in terms of flame retardant efficiency, cost controllability, and process stability.

[0099] In terms of mechanical properties, the notched impact strength of Example 1 is 58 kJ / m. 2 The tensile strength (65 MPa) and flexural strength (92 MPa) are close to the upper limits of each embodiment, and exhibit excellent isotropy (difference between transverse and longitudinal properties <5%). In Example 6, the flexural strength was increased to 98 MPa and the impact strength reached 60 kJ / m² through a "bridging-pull-out" toughening mechanism using potassium titanate whiskers. 2 Furthermore, the tensile strength fluctuated significantly (±3 MPa). Example 3 used a boron nitride and silica composite filler, which improved thermal conductivity, but the flexural strength (88 MPa) and notched impact strength (55 kJ / m²) were both lower than in Example 1, and the cost increased significantly, reflecting the trade-off between functional modification and basic mechanical properties. In Example 2, due to the increased proportion of phosphorus-nitrogen flame retardant (aluminum hypophosphite to melamine cyanurate mass ratio 3:1), the impact strength decreased to 56 kJ / m². 2 The tensile strength decreased to 63 MPa, verifying the destructive effect of excessive flame retardant on the matrix. The mechanical properties of Examples 4 and 5 were similar to those of Example 1, but the melt flowability of Example 4 was slightly reduced due to the adjustment of the siloxane ratio, and Example 5 sacrificed part of the processing window (melt index 11.9 g / 10 min) due to the optimization of the filler system and the use of nano-silicon carbide.

[0100] In terms of thermal properties, Example 1 exhibits an excellent heat distortion temperature (HDT) of 138°C. Example 3 increases the HDT to 140°C using boron nitride filler, but its flexural strength (88 MPa) and cost (filler unit price $200 / kg) become major drawbacks. Example 5 optimizes the filler system by using nano-silicon carbide, further increasing the HDT to 143°C, but the melt index decreases to 11.9 g / 10 min, limiting processing adaptability. Example 6 maintains an HDT of 137°C under extreme process conditions (high temperature and high shear), but its flame retardant efficiency decreases significantly (burning time 40 seconds). In Example 4, the HDT is slightly reduced due to adjustments in the siloxane ratio. Overall, Example 1 achieves the optimal balance between thermal stability, weather resistance, and cost control.

[0101] In terms of process and cost, Example 1 has a melt index of 12.5 g / 10 min, a wide process window, twin-screw extrusion pressure fluctuation < ±2 MPa, a yield rate ≥ 95%, and controllable raw material costs (total flame retardant addition ≤ 15%). Example 3, due to the use of expensive boron nitride ($200 / kg), increased filler costs to three times that of Example 1. Although its thermal performance is outstanding, it is difficult to promote on a large scale. Example 6, to adapt to high-speed injection molding, increased the melt index to 18.0 g / 10 min, but required customized screw components (reverse thread lead 1.3D), increasing equipment modification costs by 20%. Examples 2 and 4, due to adjustments in the proportion of flame retardant or filler, resulted in raw material costs increasing by 16% and 10% respectively, while performance improvements were limited. Although Example 5 had the best thermal and flame retardant performance, the use of more expensive fillers increased the overall cost by 15%.

[0102] Compared to Comparative Example 1, Example 1 employs a fluorine-free and halogen-free phosphorus-nitrogen-silicon synergistic flame retardant system, demonstrating significant environmental advantages over the bromine-based flame retardant system of Comparative Example 1. Although Comparative Example 1 achieved a UL94 V-0 flame retardant rating (1.5mm thickness) through the compounding of decabromodiphenyl ethane and antimony trioxide, it dripped during combustion, thus only achieving a V-2 flame retardant rating overall. Furthermore, combustion produces dibenzofuran-like toxic substances, failing to meet RoHS regulations. Regarding mechanical properties, Example 1 exhibits a notched impact strength (58kJ / m²). 2 Comparison ratio 1 (48kJ / m 2The 21% improvement is attributed to the chemical bonding interface between the silane coupling agent-modified nanofiller and the matrix, which generates a large amount of Si-OC to achieve toughening. In contrast, the brominated flame retardant in Comparative Example 1 forms 10-20 μm aggregates, becoming stress concentration sources and leading to brittle fracture. Regarding processing performance, Example 1 has a significantly higher melt index (12.5 g / 10 min) than Comparative Example 1 (9.8 g / 10 min), exhibiting superior flowability and a 15% shorter injection molding cycle. In summary, Example 1 comprehensively surpasses traditional brominated systems in terms of environmental friendliness, flame retardancy efficiency, and processing performance.

[0103] Compared to Comparative Example 2, Example 2, which used only aluminum hypophosphite (9 parts) as a flame retardant, saw its UL94 rating drop to V-1. This is because a single phosphorus-based flame retardant relies solely on condensed-phase charring and lacks the gas-phase dilution effect of melamine cyanurate (MCA) (MCA decomposes to generate NH3, reducing oxygen concentration). Furthermore, the melt index of Comparative Example 2 (7.3 g / 10 min) decreased by 42% compared to Example 1 (12.5 g / 10 min). The high aluminum hypophosphite content increased melt rigidity, leading to processing difficulties. In Example 1, the introduction of polysiloxane (2 parts) not only improved charring efficiency but also reduced melt viscosity through lubrication, completely eliminating dripping (Comparative Example 2 still exhibited a dripping tendency). This demonstrates the indispensable dual effect of phosphorus-nitrogen synergy and silicon-based modification.

[0104] Compared to Comparative Example 3, Example 1, which did not contain phenylsilsesquioxane (POSS) or polysiloxane and relied solely on a phosphorus-nitrogen flame retardant compound, had a UL94 rating reduced to V-2 (burning time 45 seconds, dripping). This is because the SiO2 network generated by the silicon-based synergist significantly improves melt strength and char formation during combustion, thereby increasing the oxygen index. Furthermore, Comparative Example 3, due to insufficient melt strength, was prone to flow marks on the injection molded parts surface, while Example 1 avoided such defects through the melt-strengthening effect of the siloxane.

[0105] Compared to Comparative Example 4, Example 1 showed a significant decrease in melt flow index (MFI) due to the increased filler content (8 parts) compared to Comparative Example 4 (12.5 g / 10 min in Example 1). Excess filler caused van der Waals agglomeration, resulting in a 34% decrease in impact strength and a deterioration in flexural strength to 65 MPa (92 MPa in Example 1). Example 1, through treatment with a silane coupling agent (KH-550), achieved uniform filler dispersion and improved interfacial shear strength. Furthermore, Comparative Example 4 exhibited reduced flame retardant performance due to filler agglomeration hindering continuous char layer formation. Additionally, the extruded strands of Comparative Example 4 showed a rough surface with visible undispersed particles, while the surface of Example 1 was smooth and defect-free, highlighting the importance of filler content.

[0106] Compared to Comparative Example 5, Example 1, which employed a high-temperature extrusion process of 270-300°C, resulted in premature decomposition of aluminum hypophosphite and loss of flame-retardant efficiency. Although the addition of bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphate antioxidant could decompose the hydroperoxides generated at high temperatures, the high temperature also triggered β-splitting of the polycarbonate backbone, generating quinone chromophores and causing significant yellowing. Example 1, through the dual protection of gradient temperature control (240-270°C) and the bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphate antioxidant, inhibited thermal degradation and exhibited excellent color stability.

[0107] Compared to Comparative Example 6, Example 1 relied solely on a silicon-based flame retardant without adding phosphorus and nitrogen components, resulting in a significant reduction in its flame retardant performance, with the UL94 rating dropping to V-1 (burning time 58 seconds). The lack of phosphorus and nitrogen synergy led to a noticeably insufficient char layer thickness. In terms of mechanical properties, the flexural strength of Comparative Example 6 (75 MPa) was lower than that of Example 1 (92 MPa) due to the absence of potassium titanate whiskers or interface optimization mechanisms, resulting in low filler reinforcement efficiency. Although the melt flow index of Comparative Example 6 (17.7 g / 10 min) was close to that of Example 1 (12.5 g / 10 min), its process stability was poor.

[0108] Comparison reveals that the fluorine-free and halogen-free flame-retardant polycarbonate material prepared using the raw materials described in this invention has excellent mechanical properties, flame-retardant properties, and processing stability. Moreover, it can be adapted to different application scenarios by adjusting the flame retardant, silicone flame retardant synergist, filler type, and process parameters, exhibiting strong scalability. Its greatest advantage lies in the fact that its components are fluorine-free and halogen-free, and are not subject to relevant policy restrictions, making it applicable to materials fields such as home appliances and consumer electronics.

[0109] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0110] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A fluorine-free and halogen-free flame-retardant polycarbonate material, characterized in that, It is prepared from the following components in parts by weight: 70-90 parts polycarbonate resin, 8-15 parts phosphorus-nitrogen flame retardant, 3-8 parts silicone flame retardant synergist, 2-5 parts nano-reinforcing filler, 0.1-0.5 parts hindered phenolic antioxidant, 0.1-0.5 parts phosphite antioxidant, and 0.1-0.5 parts pentaerythritol stearate.

2. The fluorine-free and halogen-free flame-retardant polycarbonate material according to claim 1, characterized in that, The phosphorus-nitrogen flame retardant is composed of aluminum hypophosphite and melamine cyanurate in a mass ratio of (1-3):1; in the phosphorus-nitrogen flame retardant, the particle size of aluminum hypophosphite is ≤10μm and the purity of melamine cyanurate is ≥99%.

3. The fluorine-free and halogen-free flame-retardant polycarbonate material according to claim 1, characterized in that, The silicon-based flame retardant synergist is a compound of phenylsilsesquioxane and polysiloxane in a mass ratio of 1:(1-3); in the silicon-based flame retardant synergist, the viscosity of the polysiloxane is 3000-10000cp.

4. The fluorine-free and halogen-free flame-retardant polycarbonate material according to claim 1, characterized in that, The nano-reinforcing filler is at least one of surface-modified nano-silica, surface-modified nano-kaolin, hydroxylated boron nitride, surface-modified nano-potassium titanate whiskers, and nano-silicon carbide, and the particle size of the nano-reinforcing filler is 20-100 nm.

5. The fluorine-free and halogen-free flame-retardant polycarbonate material according to claim 1, characterized in that, The polycarbonate resin has a melt index of 8-15 g / 10 min at 300℃ / 1.2 kg; the hindered phenolic antioxidant is β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate octadecyl alcohol ester; the phosphite antioxidant is bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphate ester.

6. A method for preparing a fluorine-free and halogen-free flame-retardant polycarbonate material as described in any one of claims 1-5, characterized in that, It includes the following steps: The polycarbonate resin, phosphorus-nitrogen flame retardant, silicone flame retardant synergist, nano-reinforcing filler, hindered phenolic antioxidant, phosphite antioxidant, and pentaerythritol stearate were dried separately. Phosphorus-nitrogen flame retardant, silicon-based flame retardant synergist, nano-reinforcing filler, hindered phenolic antioxidant, phosphite antioxidant, and pentaerythritol stearate are premixed in proportion; then polycarbonate resin is added in proportion for final mixing, fed into a twin-screw extruder, melted, extruded, and granulated to obtain fluorine-free and halogen-free flame-retardant polycarbonate material.

7. The method for preparing fluorine-free and halogen-free flame-retardant polycarbonate materials according to claim 6, characterized in that, The polycarbonate resin is vacuum dried in a vacuum oven at 100-120℃ for 4-6 hours until the moisture content of the polycarbonate resin is ≤0.02%; the phosphorus-nitrogen flame retardant, silicon-based flame retardant synergist, nano-reinforcing filler, hindered phenolic antioxidant, phosphite antioxidant, and pentaerythritol stearate are dried in a forced-air drying oven at 80-100℃ for 2-4 hours.

8. The method for preparing fluorine-free and halogen-free flame-retardant polycarbonate materials according to claim 6, characterized in that, The premixing speed is 600-900 r / min, and the mixing time is 5-10 min; the final mixing speed is 800-1200 r / min, and the mixing time is 5-10 min.

9. The method for preparing fluorine-free and halogen-free flame-retardant polycarbonate materials according to claim 6, characterized in that, The temperatures of each zone of the twin-screw extruder are: Zone 1 240-260℃, Zone 2 250-270℃, Zone 3 260-280℃, Zone 4 270-280℃, and the die head 270-290℃. The screw speed is 200-400 rpm.

10. The application of a fluorine-free and halogen-free flame-retardant polycarbonate material as described in any one of claims 1-5 in the field of home appliances and consumer electronics.

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