High-cost-performance, high-transparency and flame-retardant reinforced polycarbonate composite material as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of polymer composite materials, and discloses a high-cost-performance, high-transparency and flame-retardant reinforced polycarbonate composite material as well as a preparation method and application thereof. The composite material with high performance and high cost performance is successfully developed through multi-element collaborative innovation of the PC / PETG low-cost matrix, the functional nanoparticles, the low-refraction C-glass fibers and the core-shell flame retardant. The material perfectly solves the contradiction between the cost and the performance, provides an ideal material solution for the application of the material in large-scale markets of consumer electronics, household appliances, new energy automobiles and the like, and has a wide market prospect.

Description

Technical Field

[0001] This invention belongs to the field of polymer composite material technology, specifically relating to a high-performance, high-transparency, flame-retardant reinforced polycarbonate composite material, its preparation method, and its application. Background Technology

[0002] Polycarbonate (PC) is widely used due to its high light transmittance, high impact strength, and good dimensional stability. However, its inherent flame retardant properties only reach the UL94 HB level, and its flexural modulus (approximately 2.4 GPa) is insufficient for electronic products that strive for thinness and lightness. Although the modulus can be increased by adding glass fiber (GF glass fiber) and V-0 flame retardancy can be achieved by using sulfonate flame retardants, these additions often introduce severe scattering points, leading to a sharp increase in material haze, a decrease in light transmittance, and a loss of optical value.

[0003] To reduce costs while maintaining optical performance, existing technologies often employ blends of PC and the cheaper PETG. PETG, as an amorphous copolyester, exhibits good compatibility with PC and possesses high transparency and excellent chemical resistance. However, pure PC / PETG blends suffer from insufficient modulus and flame retardancy. Even with the introduction of reinforcing fibers and flame retardants, the differences between PETG's refractive index (~1.57) and E-glass fiber's (~1.55), as well as the flame retardant and multiphase interface compatibility issues, still lead to increased haze, making it difficult to simultaneously meet the comprehensive requirements of high transparency, low haze, high modulus, and flame retardancy. Furthermore, the ester bonds in PETG are prone to hydrolysis and degradation during high-temperature processing and in the presence of flame retardants, further affecting performance stability.

[0004] Therefore, developing a composite material that offers significant cost advantages while ensuring excellent overall performance (transmittance > 87%, haze < 5%, modulus > 4.5 GPa, UL94 V-0) is crucial for promoting its large-scale application in the consumer electronics and automotive sectors. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention provides a high-performance, high-transparency, flame-retardant reinforced polycarbonate composite material, its preparation method, and its applications. This composite material possesses characteristics such as high transparency, low haze, high modulus, and high flame retardancy. The above-mentioned preparation method features stable processes and low cost.

[0006] To achieve the above-mentioned objectives, the technical solution of the present invention includes: A high-performance, high-transparency, flame-retardant reinforced polycarbonate composite material, based on the total weight of the composite material, comprises the following components: 50-65 wt% polycarbonate resin, 25-35 wt% copolyester resin, 4-6 wt% surface-sulfonated zirconium oxide nanoparticles, 4-6 wt% surface-modified C-glass fiber, 0.08-0.12 wt% core-shell structured flame retardant, 0.05-0.08 wt% composite of potassium perfluorobutyl sulfonate and ionic liquid, 0.3-0.5 wt% epoxy chain extender, 0.2-0.5 wt% anti-dripping agent, and 0.5-1.5 wt% additives; wherein the core-shell structured flame retardant is a hollow SiO2 particle with hollow silica as the shell and potassium benzenesulfonate as the potassium benzenesulfonate coating.

[0007] Potassium perfluorobutyl sulfonate is a type of ionic liquid that can be used in combination with other anionic liquids. Composite flame retardants based on potassium perfluorobutyl sulfonate can be selected.

[0008] Furthermore, the thickness of the hollow silica shell is 30-50 nm, and the refractive index is 1.540-1.550.

[0009] Furthermore, the adjuvant is one or more of antioxidants, hydrolysis stabilizers, and ultraviolet absorbers. The adjuvant is selected from a combination of phosphite antioxidant 168 and hindered phenolic antioxidant 1076 or 1790, ultraviolet absorber UV360, and polycarbodiimide anti-hydrolysis agent S9000.

[0010] Furthermore, the inner layer of the surface-modified C-glass fiber is zirconium phosphate, and the outer layer is a mixed layer of silica and a small amount of titanium dioxide. Both the zirconium phosphate and silica layers are present on the surface of the C-glass fiber, forming an intermediate layer. Zirconium phosphate is a porous medium, and its refractive index can be adjusted. By filling the outer layer with silica and titanium dioxide, the refractive index can be matched between that of the C-glass fiber and PETG / PCTG, thereby reducing interface reflection and haze when light passes through.

[0011] Furthermore, the surface-modified C-glass fiber has an average diameter of 6-9 μm and a refractive index of 1.520-1.530.

[0012] Furthermore, the surface of the sulfonated zirconium oxide nanoparticles is bonded with -SO3H groups through sulfonation treatment, with an average particle size of 25-35 nm and a refractive index adjusted to 1.570-1.575.

[0013] Furthermore, the copolyester resin is PETG or PCTG.

[0014] Another aspect of the present invention provides a method for preparing such a cost-effective, highly transparent, flame-retardant reinforced polycarbonate composite material, comprising the following steps: S1: Surface-modified C-glass fiber pretreatment and flame retardant pretreatment: S1-1: An acid-resistant-refractive transition coating is constructed on the surface of C-glass fiber using sol-gel technology to obtain surface-modified C-glass fiber; S1-2: Preparation of hollow SiO2 particles coated with potassium benzenesulfonylbenzenesulfonate via microemulsion polymerization; S1-3: RIMAR is combined with the ionic liquid [BMIM]PF6 to obtain a composite of potassium perfluorobutyl sulfonate and the ionic liquid; S2: Premixing and drying: Place polycarbonate resin, PETG or PCTG resin, surface sulfonated ZrO2 nanoparticles, epoxy chain extender, anti-dripping agent and additives into a high-speed mixer and mix at low speed for 5-10 minutes to obtain a uniform premix. Place the premix in an oven at 100-120℃ and dry for 4-6 hours to remove moisture and prevent hydrolysis of PETG or PCTG. S3: Melt blending and granulation: The premix obtained in step S2 is fed into the twin-screw extruder through the main feed port, and the surface-modified C-glass fiber is fed into the side feed port. The hollow SiO2 particles coated with potassium benzenesulfonate obtained in step S1-2 and the RIMAR composite obtained in step S1-3 are injected into the melting section through a liquid injection pump. Melt extrusion is carried out under the conditions of 245-260℃, screw speed 200-300rpm, and vacuum degree ≥-0.09 MPa. The particles are then water-cooled, drawn into strips, and granulated to obtain composite material particles. S4: Molding: The composite material particles obtained in step S3 are dried again at 100-120℃ for 2-4 hours, and then molded into products by injection molding machine under low temperature and low pressure conditions of mold temperature 70-85℃ and injection pressure 30-45 MPa.

[0015] Another aspect of the present invention provides the application of this high-performance, high-transparency, flame-retardant reinforced polycarbonate composite material in the preparation of smartphone casings, tablet protective cases, transparent covers for home appliances, translucent signage for new energy vehicles, and battery pack observation windows.

[0016] Compared with the prior art, the beneficial effects of the present invention are reflected in: (1) The composite material of the present invention has excellent comprehensive performance. Specifically, the optical properties of the composite material in the present invention are as follows: by matching the refractive index of the PC / PETG matrix, selecting low-refractive C-glass fiber and designing its surface transition coating, and filling and adjusting the refractive index of the interface micro-defects with surface sulfonated ZrO2 nanoparticles (n≈1.572), extremely low interface light scattering is achieved. The final composite material has a transmittance of over 87.5% and a haze of less than 4.5%.

[0017] The mechanical properties of the composite material in this invention are as follows: Through the reinforcement of 4-6 wt% C-glass fiber and the rigidity enhancement effect of nanoparticles, the flexural modulus of the material is increased to 4.5-5.0 GPa, meeting the rigidity requirements of thin-walled structural components. The addition of chain extender effectively inhibits hydrolytic degradation during processing, ensuring the stability of molecular weight and impact strength.

[0018] The flame retardant properties of the composite material in this invention are achieved by employing an ultra-low addition amount (total <0.2 wt%) of a compound sulfonate flame retardant system. The KSS@hollow SiO2 core-shell structure effectively inhibits KSS agglomeration, solving the problem of increased haze; the ionic liquid composite promotes the dispersion and catalytic efficiency of RIMAR; and sulfonated ZrO2 nanoparticles and flame retardants synergistically catalyze char formation. Ultimately, a UL94 V-0 (1.8 mm) rating is achieved with no dripping.

[0019] (2) The composite material in this invention has a significant cost advantage.

[0020] Specifically, PETG or PCTG, which are significantly cheaper than PC and COC (cost reduction of 20%-30%), are introduced into the matrix resin, greatly reducing raw material costs. Through ingenious multi-component synergistic design, the target performance is achieved with extremely low amounts of flame retardant and glass fiber, further saving on the cost of expensive additives. The processing temperature window (245-260℃) is lower than that of the pure PC system, reducing production energy consumption, increasing equipment life, and facilitating large-scale production.

[0021] Excellent process stability and weather resistance: The intrinsic acid resistance of C-glass fiber avoids corrosion from sulfonates. Special surface treatment processes, strict drying regimes, and the introduction of chain extenders effectively overcome the shortcomings of easy hydrolysis of PETG or PCTG, ensuring the stability of material performance during processing and use. Detailed Implementation

[0023] The technical solution of the present invention will be further described in detail below with reference to specific embodiments.

[0024] Example 1 This embodiment presents a high-performance, high-transparency, flame-retardant reinforced polycarbonate composite material, comprising the following components based on the total weight of the composite material: 50-65 wt% polycarbonate resin, 25-35 wt% copolyester resin, 4-6 wt% surface-sulfonated zirconium oxide nanoparticles, 4-6 wt% surface-modified C-glass fiber, 0.08-0.12 wt% core-shell structured flame retardant, 0.05-0.08 wt% a composite of potassium perfluorobutyl sulfonate and ionic liquid, 0.3-0.5 wt% epoxy chain extender, 0.2-0.5 wt% anti-dripping agent, and 0.5-1.5 wt% additives; the core-shell structured flame retardant consists of hollow SiO2 particles coated with potassium benzenesulfonate as the potassium benzenesulfonate shell.

[0025] This embodiment describes a method for preparing a high-performance, high-transparency, flame-retardant reinforced polycarbonate composite material, comprising the following steps: S1: Surface-modified C-glass fiber pretreatment and flame retardant pretreatment: S1-1: An acid-resistant-refractive transition coating is constructed on the surface of C-glass fiber using sol-gel technology to obtain surface-modified C-glass fiber; S1-2: Preparation of hollow SiO2 particles coated with potassium benzenesulfonylbenzenesulfonate via microemulsion polymerization; S1-3: RIMAR is combined with the ionic liquid [BMIM]PF6 to obtain a composite of potassium perfluorobutyl sulfonate and the ionic liquid; S2: Premixing and drying: Place polycarbonate resin, PETG or PCTG resin, surface sulfonated ZrO2 nanoparticles, epoxy chain extender, anti-dripping agent and additives into a high-speed mixer and mix at low speed for 5-10 minutes to obtain a uniform premix. Place the premix in an oven at 100-120℃ and dry for 4-6 hours to remove moisture and prevent hydrolysis of PETG or PCTG. S3: Melt blending and granulation: The premix obtained in step S2 is fed into the twin-screw extruder through the main feed port, and the surface-modified C-glass fiber is fed into the side feed port. The hollow SiO2 particles coated with potassium benzenesulfonate obtained in step S1-2 and the RIMAR composite obtained in step S1-3 are injected into the melting section through a liquid injection pump. Melt extrusion is carried out under the conditions of 245-260℃, screw speed 200-300rpm, and vacuum degree ≥-0.09 MPa. The particles are then water-cooled, drawn into strips, and granulated to obtain composite material particles. S4: Molding: The composite material particles obtained in step S3 are dried again at 100-120℃ for 2-4 hours, and then molded into products by injection molding machine under low temperature and low pressure conditions of mold temperature 70-85℃ and injection pressure 30-45 MPa.

[0026] Example 2 This embodiment describes a method for preparing a high-performance, high-transparency, flame-retardant reinforced polycarbonate composite material, comprising the following steps: S1: Surface-modified C-glass fiber pretreatment and flame retardant pretreatment.

[0027] S2: Pour PC, PETG, sulfonated ZrO2, chain extender, PTFE and additives into a high-speed mixer and mix at 600 rpm for 8 minutes.

[0028] The premix was dried at 110°C for 5 hours.

[0029] S3: The dried premix is ​​fed into the twin-screw extruder through the main feed port, and the modified C-glass fiber is added through the side feed port. Both flame retardants are injected into zone five via a liquid injection pump. The temperatures for each zone are set as follows: Zone 1 220℃, Zone 2 240℃, Zones 3-7 255℃, and the die head 250℃. The screw speed is 250 rpm, and vacuum devolatilization is used.

[0030] The extruded strips are cooled with water, air-dried, and then granulated to obtain composite material particles.

[0031] S4: The granules are dried at 105°C for 3 hours, and then molded into standard test strips and mobile phone shell samples using an injection molding machine (barrel temperature 250°C, mold temperature 80°C, injection pressure 38 MPa). Comparative Example Compared to the previous examples, ordinary E-glass fiber (unmodified, n=1.558) was used, and the flame retardant was a simple mixture of uncoated KSS and RIMAR, without the use of sulfonated nanoparticles and chain extenders. The amount of PETG was the same, while the amount of PC was increased accordingly to compensate for missing components. The rest of the process was the same.

[0033] Table performance and cost testing Test Project Test Standards Example 2 Comparative Example Pure PC Reference Light transmittance (%) ASTM D1003 88.2 75.4 90.5 Haze (%) ASTM D1003 3.9 25.6 0.9 Flexural modulus (GPa) ISO 178 4.70 4.95 2.40 Notched impact strength (kJ / m²) ISO 179 / 1eA 52 35 65 UL94 rating (1.8 mm) UL94 V-0 V-2 (Melting Droplet) HB Material cost index - 100 105 135 Processing temperature (°C) - 255 275 300 As shown in the table, the sample in Example 2 exhibits outstanding overall performance and cost advantages. Compared to the comparative example, Example 2, through innovation in components and processes, achieves superior optical performance (88.2% transmittance, 3.9% haze) and flame retardant performance (V-0) at a lower cost, while maintaining high modulus and good toughness. The comparative example, due to poor interfacial compatibility, flame retardant agglomeration, and easy hydrolysis, fails to meet the standards for both optical and flame retardant performance. Compared to pure PC, Example 2 achieves a doubling of modulus and V-0 flame retardancy at the cost of a small sacrifice in transmittance, while significantly reducing cost.

[0034] Application Example 1 The granules obtained in the examples were injection molded. Smartphone casing: The casing is 0.7mm thick, with a transparent texture that reveals the internal design. It is high-strength, scratch-resistant, and has passed the stringent flame-retardant certifications of all domestic and international operators. Its overall cost is highly competitive in the market. Application Example 2 The granules obtained in the examples are injection molded. Illuminated door railings for new energy vehicles: As a light-transmitting identification component, the light is soft and uniform, resistant to wiping by chemicals inside the vehicle (such as alcohol and cleaning agents), and flame-retardant and safety meets automotive-grade requirements.

[0036] Application Example 3 The granules obtained in the examples are injection molded. Transparent air purifier shell: The overall appearance is high-end and transparent, allowing the internal structure to be displayed. The rigidity of the material ensures that the product is not easily deformed, and the flame-retardant properties provide a guarantee for the safety of household appliances.

[0037] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any simple modifications, equivalent changes and alterations made based on the technical essence of the present invention shall still fall within the scope of the technical solution of the present invention.

Claims

1. A high-performance, high-transparency, flame-retardant reinforced polycarbonate composite material, characterized in that, Based on the total weight of the composite material, it comprises the following components: 50-65 wt% polycarbonate resin, 25-35 wt% copolyester resin, 4-6 wt% surface-sulfonated zirconium oxide nanoparticles, 4-6 wt% surface-modified C-glass fiber, 0.08-0.12 wt% core-shell structured flame retardant, 0.05-0.08 wt% composite of potassium perfluorobutyl sulfonate and ionic liquid, 0.3-0.5 wt% epoxy chain extender, 0.2-0.5 wt% anti-dripping agent, and 0.5-1.5 wt% additives.

2. The high-performance, high-transparency, flame-retardant reinforced polycarbonate composite material as described in claim 1, characterized in that, The core-shell structure flame retardant consists of hollow SiO2 particles coated with hollow silica as the shell and potassium benzenesulfonate as the potassium benzenesulfonate.

3. The high-performance, high-transparency, flame-retardant reinforced polycarbonate composite material as described in claim 2, characterized in that, The hollow silica shell has a thickness of 30-50 nm and a refractive index of 1.540-1.

550.

4. The high-performance, high-transparency, flame-retardant reinforced polycarbonate composite material as described in claim 1, characterized in that, The additive is one or more of antioxidants, hydrolytic stabilizers, and ultraviolet absorbers.

5. The high-performance, high-transparency, flame-retardant reinforced polycarbonate composite material as described in claim 1, characterized in that, The inner layer of the surface-modified C-glass fiber is zirconium phosphate, and the outer layer is a mixture of silicon dioxide and a small amount of titanium dioxide.

6. The high-performance, high-transparency, flame-retardant reinforced polycarbonate composite material as described in claim 1, characterized in that, The surface-modified C-glass fiber has an average diameter of 6-9 μm and a refractive index of 1.520-1.

530.

7. The high-performance, high-transparency, flame-retardant reinforced polycarbonate composite material as described in claim 1, characterized in that, The surface of the sulfonated zirconium oxide nanoparticles is bonded with -SO3H groups through sulfonation treatment, with an average particle size of 25-35 nm and a refractive index adjusted to 1.570-1.

575.

8. The high-performance, high-transparency, flame-retardant reinforced polycarbonate composite material as described in claim 1, characterized in that, The copolyester resin is PETG or PCTG.

9. The method for preparing the high-performance, high-transparency, flame-retardant reinforced polycarbonate composite material as described in claims 1-7, characterized in that, Includes the following steps: S1: Surface-modified C-glass fiber pretreatment and flame retardant pretreatment: S1-1: An acid-resistant-refractive transition coating is constructed on the surface of C-glass fiber using sol-gel technology to obtain surface-modified C-glass fiber; S1-2: Preparation of hollow SiO2 particles coated with potassium benzenesulfonylbenzenesulfonate via microemulsion polymerization; S1-3: RIMAR is combined with the ionic liquid [BMIM]PF6 to obtain a composite of potassium perfluorobutyl sulfonate and the ionic liquid; S2: Premixing and drying: Place polycarbonate resin, PETG or PCTG resin, surface sulfonated ZrO2 nanoparticles, epoxy chain extender, anti-dripping agent and additives into a high-speed mixer and mix at low speed for 5-10 minutes to obtain a uniform premix. Place the premix in an oven at 100-120℃ and dry for 4-6 hours to remove moisture and prevent hydrolysis of PETG or PCTG. S3: Melt blending and granulation: The premix obtained in step S2 is fed into the twin-screw extruder through the main feed port, and the surface-modified C-glass fiber is fed into the side feed port. The potassium benzenesulfonate-coated hollow SiO2 particles obtained in step S1-2 and the composite of potassium perfluorobutyl sulfonate and ionic liquid obtained in step S1-3 are injected into the melting section through a liquid injection pump. Melt extrusion is carried out under the conditions of 245-260℃, screw speed 200-300 rpm, and vacuum degree ≥-0.09 MPa. The particles are then water-cooled, drawn into strips, and granulated to obtain composite material particles. S4: Molding: The composite material particles obtained in step S3 are dried again at 100-120℃ for 2-4 hours, and then molded into products by injection molding machine under low temperature and low pressure conditions of mold temperature 70-85℃ and injection pressure 30-45 MPa.

10. The application of the high-performance, high-transparency, flame-retardant reinforced polycarbonate composite material as described in claims 1-7 in the preparation of smartphone casings, tablet protective cases, transparent covers for home appliances, translucent identification plates for new energy vehicles, and observation windows for battery packs.