PFAS-free flame-retardant polycarbonate composition as well as preparation method and application thereof

Abstract

The invention discloses a PFAS-free flame-retardant polycarbonate composition as well as a preparation method and application thereof. The PFAS-free flame-retardant polycarbonate composition is prepared from the following components in parts by weight: 49 to 71 parts of polycarbonate resin, 9 to 41 parts of polyphenylene sulfone resin, 10 to 30 parts of glass fiber and 0.5 to 2 parts of compatilizer, the weight-average molecular weight of the polycarbonate resin is 20000 to 36000; the weight-average molecular weight of the polyphenylene sulfone resin is 20000 to 40000; the average retention length of the glass fibers is 180-310 [mu] m, and the compatilizer is selected from at least one of maleic anhydride grafted polystyrene and epoxy group grafted SAN. The flame-retardant polycarbonate composition has excellent flame retardant property, anti-dripping property and mechanical property on the premise of no PFAS (PolyfluoroAcrylonitrile Styrene).

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of engineering plastics, and more particularly relates to a PFAS-free flame-retardant polycarbonate composition and a preparation method and application thereof. BACKGROUND

[0002] Due to the aromatic carbonate bond structure in the molecular chain and the unique Fries rearrangement reaction in the combustion process, polycarbonate (PC) can produce a small amount of char during combustion, reduce the combustion time, and reduce the melt viscosity through the Fries rearrangement reaction to produce large particle melt drops to completely take away the combustion material, thereby achieving the UL94 flame retardant level of PC intrinsic flame retardant V-2.

[0003] In the actual application scenario of PC, the flame retardant level of PC material often needs to meet the V-0 of the actual thickness of the corresponding product, and therefore the PC needs to be flame-retardant modified. However, the unique Fries rearrangement reaction of PC can cause a large drop in the melt viscosity and cause dripping, and therefore a perfluoro and polyfluoro alkyl substance (PFAS) such as polytetrafluoroethylene is added as an anti-dripping agent to inhibit the dripping behavior of PC in the mainstream flame-retardant PC scheme.

[0004] However, with the update and implementation of the EU PFAS substance regulation, PFAS is about to be completely banned. Therefore, how to provide a PFAS-free flame-retardant polycarbonate composition has become a technical problem to be solved. SUMMARY

[0005] In view of the above technical problems, the primary purpose of the present application is to provide a PFAS-free flame-retardant polycarbonate composition, which has excellent flame-retardant performance, anti-dripping performance and mechanical properties under the premise of being PFAS-free.

[0006] The second purpose of the present application is to provide a preparation method of the PFAS-free flame-retardant polycarbonate composition.

[0007] The third purpose of the present application is to provide an application of the PFAS-free flame-retardant polycarbonate composition in electrical appliances and consumer electronics.

[0008] The fourth purpose of the present application is to provide a power charger or adapter.

[0009] In order to achieve the above purposes, the present application is implemented by the following technical scheme: The present application claims a PFAS-free flame-retardant polycarbonate composition, which comprises the following components in parts by weight: polycarbonate resin 49-71 parts, polyphenylene sulfone resin 9-41 parts, glass fiber 10-30 parts, and compatibilizer 0.5-2 parts. The weight average molecular weight of the polycarbonate resin is 20000-36000; The weight average molecular weight of the polyphenylene sulfone resin is 20000-40000; The average retention length of the glass fiber is 180-310 μm; The compatibilizer is selected from at least one of maleic anhydride grafted polystyrene and epoxy group grafted SAN.

[0010] The PFAS-free flame-retardant polycarbonate composition provided by the present application is filled by introducing a polyphenylene sulfone resin (PPSU) and glass fibers, realizing PFAS-free flame-retardant performance without conventional flame retardants and anti-dripping agents. The conjugated π bond of the aromatic ring in the PPSU molecular structure and the bond energy of the S=O bond in the sulfone group are extremely strong, so that the stability of the PPSU molecular chain is extremely high, which makes it difficult to produce flammable small molecules during the combustion process, thereby reducing the amount of flammable substances from the source. At the same time, the sulfur atom in the sulfone group is in a high oxidation state and is difficult to further oxidize during combustion, which makes it need to burn in a higher concentration of oxygen atmosphere. When PPSU is introduced into the PC resin matrix, the limiting oxygen index of the system is significantly improved, and the total combustion time of the material is greatly shortened.

[0011] Further, the inventors found through research that the molecular weight of the PPSU resin and the PC resin greatly affects the anti-dripping performance and flame-retardant performance of the polycarbonate composition; when the molecular weight is too low, the melt viscosity of the material is also low, and during the combustion process, the low melt viscosity cannot bear the gravity of the end combustion area, thereby causing dripping. When the molecular weight is too high, the dispersion uniformity of the PPSU resin after blending is poor, which cannot uniformly improve the limiting oxygen index of the material, causing the material to fluctuate during combustion. At the same time, the high viscosity significantly enhances the shear force during the extrusion process, thereby reducing the average retention length of the glass fiber and affecting the construction of the glass fiber "skeleton network". Therefore, the specific compatibilizer used in the present application improves the dispersion uniformity of the PPSU resin and the PC resin, and enhances the interfacial compatibility between the glass fiber and the resin matrix, so that they uniformly disperse to form a "skeleton network" and inhibit the dripping phenomenon caused by the large decrease in melt viscosity during PC combustion. Finally, a PFAS-free flame-retardant V-0 polycarbonate composition is obtained.

[0012] Further, the inventors found through research that the average retention length of the glass fiber in the system determines the formation of the skeleton network. When the average retention length is too short, the glass fiber in the matrix material presents an "island-sea" dispersion phase state, at which time the glass fibers cannot contact and connect each other to form a network structure, so they cannot prevent the dripping behavior during the combustion of the material. When the average retention length is too long, the candle core effect is significantly enhanced, causing the material to continue to burn along the glass fiber, which does not reach the V-0 flame-retardant grade.

[0013] Specifically, the fraction of the polycarbonate resin can be 50 parts, 55 parts, 60 parts, 65 parts, 70 parts, etc., or an interval range formed by any of the above values, and the present application is not limited thereto. The fraction of the polyphenylene sulfone resin can be 10 parts, 15 parts, 20 parts, 25 parts, 30 parts, 35 parts, 40 parts, etc., or an interval range formed by any of the above values, and the present application is not limited thereto. The fraction of the glass fiber can be 10 parts, 15 parts, 20 parts, 25 parts, etc., or an interval range formed by any of the above values, and the present application is not limited thereto. The fraction of the compatilizer can be 0.8 parts, 1 part, 1.2 parts, 1.4 parts, 1.6 parts, 1.8 parts, etc., or an interval range formed by any of the above values, and the present application is not limited thereto.

[0014] Specifically, in the present application, the mass percentage of the polycarbonate resin in the polycarbonate composition is not less than 40.1%; more specifically, the mass percentage is not less than 49.2%. Specifically, in the present application, the mass percentage of the polyphenylene sulfone resin in the polycarbonate composition is not less than 8.0%; more specifically, the mass percentage is not less than 9.9%. Specifically, in the present application, the mass ratio of the polycarbonate resin and the polyphenylene sulfone resin is (1-8):1; specifically, the mass ratio is (1.25-7):1. More specifically, the mass ratio of the polycarbonate resin and the polyphenylene sulfone resin can be 1:1, 2:1, 3:1, 4:1, 5:1, 6:1, 7:1, etc., or an interval range formed by any of the above values, and the present application is not limited thereto.

[0015] Specifically, the weight average molecular weight of the polycarbonate resin is 21000-35000. Specifically, the weight average molecular weight of the polycarbonate resin can be 20000, 23000, 25000, 28000, 30000, 33000, 35000, etc., or an interval range formed by any of the above values, and the present application is not limited thereto. Specifically, the test method of the weight average molecular weight of the polycarbonate resin is GB / T 36214.4-2018, the solvent is chloroform, and the weight average molecular weight standard sample is polystyrene.

[0016] Specifically, the weight average molecular weight of the polyphenylene sulfone resin is 22000-40000. Specifically, the weight average molecular weight of the polyphenylene sulfone resin can be 25000, 28000, 30000, 32000, 35000, 38000, etc., or an interval range formed by any of the above values, and the present application is not limited thereto. Specifically, the test method of the weight average molecular weight of the polyphenylene sulfone resin is GB / T 36214.4-2018, the solvent is chloroform, and the weight average molecular weight standard sample is polystyrene.

[0017] Specifically, the average retention length of the glass fiber is 200-300 μm. More specifically, the average retention length of the glass fiber can be 210 μm, 220 μm, 230 μm, 240 μm, 250 μm, 260 μm, 270 μm, 280 μm, 290 μm, etc., or an interval range formed by any of the above values, and the application is not limited thereto. Specifically, the test method for the average retention length of the glass fiber is ISO 22314:2006. More specifically, in some specific test methods, the polycarbonate composition sample is calcined in a muffle furnace at 650-750 ℃ for 2 h, the calcined sample is taken out, placed on a glass slide and flattened, and then placed under a microscope to select 300 glass fibers, measure their retention length, and calculate the average value to obtain the average retention length of the glass fiber.

[0018] Specifically, the average retention length of the glass fiber can be adjusted by those skilled in the art through conventional methods in the art, including but not limited to: adjusting the average retention length of the glass fiber by feeding the glass fiber into the twin-screw extruder through the main feeding or side feeding during processing; adjusting the speed or temperature of the feeding and other preparation conditions; using glass fiber raw materials of different lengths; adjusting the weight average molecular weight of the polycarbonate resin and the polyphenylene sulfone resin, etc.

[0019] Preferably, in the maleic anhydride grafted polystyrene, the grafting rate of maleic anhydride is 10-24%; the grafting rate is 16-20%. More specifically, the grafting rate of maleic anhydride can be 12%, 14%, 16%, 18%, 20%, 22%, etc., or an interval range formed by any of the above values, and the application is not limited thereto. Specifically, the test method for the grafting rate of maleic anhydride is infrared spectroscopy.

[0020] Preferably, in the epoxy group grafted SAN (styrene-acrylonitrile-glycidyl methacrylate copolymer), the content of the epoxy group is 0.5-3%; the content of the epoxy group is 1.5-2.5%. More specifically, the content of the epoxy group can be 0.5%, 0.8%, 1.0%, 1.2%, 1.5%, 1.8%, 2.0%, 2.2%, 2.5%, 2.8%, etc., or an interval range formed by any of the above values, and the application is not limited thereto. Specifically, the test method for the epoxy group is infrared spectroscopy.

[0021] Preferably, the compatibilizer is selected from at least one of maleic anhydride grafted polystyrene, styrene-acrylonitrile-glycidyl methacrylate. Under the preferred compatibilizer conditions, the polycarbonate composition prepared has a higher limiting oxygen index and has more excellent flame retardant performance.

[0022] Preferably, the melt flow rate of the polycarbonate resin under the condition of 300℃, 1.2kg is 5-35g / 10min. Specifically, the melt flow rate of the polycarbonate resin under the condition of 300℃, 1.2kg can be 10g / 10min, 15g / 10min, 25g / 10min, 35g / 10min, etc., or an interval range formed by any of the above values, and the present application is not limited thereto. Specifically, the test method of the melt flow rate of the polycarbonate resin is GB / T 3682.1-2018.

[0023] Preferably, the melt flow rate of the polyphenylene sulfone resin under the condition of 365℃, 10kg is 20-45g / 10min. The melt flow rate of the polyphenylene sulfone resin under the condition of 365℃, 10kg can be 20g / 10min, 30g / 10min, 35g / 10min, 45g / 10min, etc., or an interval range formed by any of the above values, and the present application is not limited thereto. Specifically, the test method of the melt flow rate of the polyphenylene sulfone resin is GB / T 3682.1-2018.

[0024] Preferably, the polycarbonate resin is a bisphenol A type polycarbonate resin.

[0025] Preferably, the PFAS-free flame-retardant polycarbonate composition further comprises at least one of an antioxidant, a lubricant, a toughening agent.

[0026] Preferably, at least one selected from the following (a) to (c) is selected: (a) the antioxidant is a phosphite antioxidant; (b) the lubricant is at least one selected from pentaerythritol ester lubricants, stearate lubricants, paraffin lubricants, amide lubricants; (c) the toughening agent is at least one selected from silicon-based toughening agents, styrene-based block copolymers, acrylate polymers, ethylene copolymers.

[0027] More specifically, the phosphite antioxidant includes but is not limited to bis(2,4-dicumylphenyl)pentaerythritol-diphosphite, tris[2.4-di-tert-butylphenyl]phosphite, etc. More specifically, the lubricant includes but is not limited to pentaerythritol tetrastearate, pentaerythritol tetrapalmitate, pentaerythritol tetraoleate, pentaerythritol tetralaurate, etc. More specifically, the toughening agent includes but is not limited to SBS, SEBS, MBS, ethylene-vinyl acetate copolymer, etc.

[0028] Further, the application claims a preparation method of the PFAS-free flame-retardant polycarbonate composition, which uniformly mixes the raw materials of each component, uses a side feeding method to feed the glass fiber, and melts and extrudes to obtain the PFAS-free flame-retardant polycarbonate composition.

[0029] Preferably, the temperature of the melt extrusion is 280-330℃. Further preferably, the temperature of the melt extrusion is 300-320℃.

[0030] Preferably, the extrusion is performed by using a double-screw extruder. The length-diameter ratio of the double-screw extruder is 40-50:1.

[0031] Preferably, the rotation speed of the double-screw extruder is 200-500 r / min. Further preferably, the rotation speed of the double-screw extruder is 300-400 r / min.

[0032] Further, the application claims an application of the PFAS-free flame-retardant polycarbonate composition in electrical appliances and consumer electronics.

[0033] Specifically, the content of fluorine element in the PFAS-free flame-retardant polycarbonate composition of the application is less than 1 ppm; more specifically, the content of fluorine element is less than 50 ppb.

[0034] More specifically, the specific application scenarios in the field of electrical appliances refer to electrical appliances that need to be exposed to heating or high temperature for a long time, such as electrical equipment circuit boards, peripheral structural supports, etc. More specifically, the specific application scenarios in the field of consumer electronics refer to internal electronic component supports of power chargers, power adapters, sound equipment, earphones, etc.

[0035] Further, the application claims a power charger or adapter using the above-mentioned PFAS-free flame-retardant polycarbonate composition.

[0036] Compared with the prior art, the application has the following beneficial effects: The application provides a PFAS-free flame-retardant polycarbonate composition, which controls the molecular weight of PPSU resin and PC resin, controls the average retention length of glass fiber, and combines specific compatibilizers, so that the prepared polycarbonate composition has excellent flame-retardant performance, anti-dripping performance, and mechanical properties under the premise of being PFAS-free. DETAILED DESCRIPTION

[0037] The application is further illustrated below in combination with the specification and specific examples, but the examples do not limit the application in any form. Unless otherwise specified, the reagents, methods, and equipment used in the application are conventional reagents, methods, and equipment in the technical field.

[0038] Polycarbonate Resin 1, melt flow rate at 300℃, 1.2kg condition is 30g / 10min, weight average molecular weight is 21000, PC 1350, Wanhua Chemical.

[0039] Polycarbonate Resin 2, melt flow rate at 300℃, 1.2kg condition is 5g / 10min, weight average molecular weight is 35000, PC 2050, Wanhua Chemical.

[0040] Polycarbonate Resin 3, melt flow rate at 300℃, 1.2kg condition is 60g / 10min, weight average molecular weight is 17000, PC 2600, Wanhua Chemical.

[0041] Polycarbonate Resin 4, melt flow rate at 300℃, 1.2kg condition is 3g / 10min, weight average molecular weight is 40000, PC 7030PJ, Mitsubishi.

[0042] Polyphenylene sulfone Resin 1, melt flow rate at 365℃, 10kg condition is 40g / 10min, weight average molecular weight is 22000, G-KFSU15B, Zhuhai Wantongte Plastic.

[0043] Polyphenylene sulfone Resin 2, melt flow rate at 365℃, 10kg condition is 20g / 10min, weight average molecular weight is 40000, G-KFSU11B, Zhuhai Wantongte Plastic.

[0044] Polyphenylene sulfone Resin 3, melt flow rate at 365℃, 10kg condition is 60g / 10min, weight average molecular weight is 15000, G-KFSU20B, Zhuhai Wantongte Plastic.

[0045] Polyphenylene sulfone Resin 4, melt flow rate at 365℃, 10kg condition is 15g / 10min, weight average molecular weight is 43000, G-KFSU10B, Zhuhai Wantongte Plastic.

[0046] Compatibilizer 1, maleic anhydride grafted polystyrene, grafting rate of maleic anhydride is 18%, SMA-700, Huawen New Material.

[0047] Compatibilizer 2, styrene-acrylonitrile-glycidyl methacrylate, content of epoxy group is 2%, SAG-002, Jiaiyirong.

[0048] Compatibilizer 3, maleic anhydride grafted polypropylene, grafting rate of maleic anhydride is 1.0%, EPA-830P, Haifeng New Material.

[0049] Glass fiber, length is 4.5mm, ECS13-4.5-510H, Jushi Glass Fiber.

[0050] Lubricant, pentaerythritol stearate, PETS-AP, Italian FAG.

[0051] Antioxidant, bis(2,4-dicumylphenyl)pentaerythritol-diphosphite, RIANOX 686, Tianjin Lialong.

[0052] Toughening agent, silicon-based toughening agent, S-2501, Mitsubishi, Japan.

[0053] Unless otherwise specified, all components used in the parallel embodiments and comparative examples are the same commercially available products.

[0054] Examples 1-8 A PFAS-free flame-retardant polycarbonate composition is prepared according to the formulation weight parts in Table 1-2 and the preparation method including the following steps: after uniformly mixing all raw materials except glass fiber, the glass fiber is fed in a side-feed manner and melt-extruded through a twin-screw extruder (length-to-diameter ratio of 48:1) (320℃, 300 r / min) to obtain the PFAS-free flame-retardant polycarbonate composition.

[0055] Table 1

[0056] Table 2

[0057] Comparative Examples 1-10 The weight proportions of raw materials used in the following comparative examples are shown in Table 3. The preparation method is the same as that in Example 1 above.

[0058] The difference between Comparative Example 5 and Example 1 is that the length-to-diameter ratio of the twin-screw extruder is 60:1.

[0059] The difference between Comparative Example 6 and Example 1 is that the length-to-diameter ratio of the twin-screw extruder is 32:1.

[0060] Table 3

[0061] Test case The PFAS-free flame-retardant polycarbonate compositions obtained in the above examples and comparative examples were tested as follows.

[0062] (1) Flame retardancy rating: Flame retardancy test was conducted according to the procedure of "Flammability Test of Plastic Materials, UL94". The flame retardancy rating was determined based on the burning rate, extinguishing time, whether it dripped, and whether the dripping ignited the cotton wool. The sample used for testing was 125 mm in length, 13 mm in width, and 1.0 mm in thickness.

[0063] (2) Limiting oxygen index (%): The limiting oxygen index is tested according to ISO 4589-2:1996.

[0064] (3) Bending modulus (MPa): Bending strength is tested according to ASTM D790 standard.

[0065] (4) Bending strength (MPa): Bending modulus is tested according to ASTM D790 standard.

[0066] Tables 4 and 5 show the test data for the PFAS-free flame-retardant polycarbonate compositions prepared in the examples and comparative examples, respectively.

[0067] Table 4

[0068] Table 5

[0069] As shown in Tables 4 and 5 above, the PFAS-free flame-retardant polycarbonate compositions provided by this invention possess excellent anti-dripping ignition properties, flame-retardant properties, and mechanical properties. Specifically, the flame-retardant rating of all polycarbonate compositions reaches V-0, they do not drip and ignite, their limiting oxygen index is ≥37%, their flexural modulus is ≥3400 MPa, and their flexural strength is ≥95 MPa.

[0070] As can be seen from Examples 1, 5, and Comparative Examples 1-2, when the weight-average molecular weight of the polycarbonate resin is within a specific range, the prepared polycarbonate composition can achieve a flame retardant rating of V-0 and will not drip and ignite; in addition, it also has superior mechanical properties.

[0071] As can be seen from Examples 1, 6, and Comparative Examples 3-4, only when the weight-average molecular weight of polyphenylene sulfone resin is within a specific range can the prepared polycarbonate composition achieve a flame retardant rating of V-0 and not drip and ignite.

[0072] As can be seen from Examples 1, 7, and Comparative Example 7, when maleic anhydride-grafted polypropylene is used as the compatibilizer, the polycarbonate composition prepared cannot achieve the technical effect.

[0073] As shown in Examples 1, 5-6, and 8, when the average retention length of the glass fibers is short, the polymer burns to charcoal, which is insufficient to connect the glass fibers to form a network. Furthermore, because glass fibers are dense, they are more prone to dripping and igniting. In addition, the polycarbonate composition exhibits low flexural modulus and flexural strength, failing to achieve the technical effects of this invention. When the average retention length of the glass fibers is long, the polymer burns continuously along the glass fibers, making it difficult to extinguish and significantly prolonging the burning time, thus degrading the flame retardant rating. The resulting polycarbonate composition fails to achieve the technical effects of this invention. Similarly, the technical effects of this invention cannot be achieved when glass fibers are not added to the system.

[0074] As can be seen from Examples 1, 9, and 10, the technical effects of the present invention cannot be achieved when the system does not contain polyphenylsulfone resin or when the mass ratio of polycarbonate resin to polyphenylsulfone resin is not within the specified range.

[0075] The foregoing examples are merely illustrative, used to explain some features of the method described in this invention. The appended claims are intended to claim the broadest possible scope, and the embodiments presented herein are demonstrated by the applicant's actual experimental results. Therefore, the applicant intends that the appended claims are not limited by the selection of examples illustrating the features of the invention. Some numerical ranges used in the claims also include sub-ranges within them, and variations within these ranges should also be interpreted as being covered by the appended claims where possible.

Claims

1. A PFAS-free flame-retardant polycarbonate composition, characterized in that, By weight, it comprises the following components: 49-71 parts polycarbonate resin, 9-41 parts polyphenyl sulfone resin, 10-30 parts glass fiber, and 0.5-2 parts compatibilizer. The weight-average molecular weight of the polycarbonate resin is 20,000-36,000; The weight-average molecular weight of the polyphenylene sulfone resin is 20,000-40,000. The average retention length of the glass fiber is 180-310 μm; The compatibilizer is selected from at least one of maleic anhydride-grafted polystyrene and epoxy group-grafted SAN.

2. The PFAS-free flame-retardant polycarbonate composition according to claim 1, characterized in that, In maleic anhydride-grafted polystyrene, the grafting rate of maleic anhydride is 10-24%; and / or In epoxy-grafted SAN, the content of epoxy groups is 0.5-3%.

3. The PFAS-free flame-retardant polycarbonate composition according to claim 1, characterized in that, The polycarbonate resin is a bisphenol A type polycarbonate resin.

4. The PFAS-free flame-retardant polycarbonate composition according to claim 1, characterized in that, The polycarbonate resin has a melt flow rate of 5-35 g / 10 min at 300°C and 1.2 kg.

5. The PFAS-free flame-retardant polycarbonate composition according to claim 1, characterized in that, The polyphenylene sulfone resin has a melt flow rate of 20-45 g / 10 min at 365°C and 10 kg.

6. The PFAS-free flame-retardant polycarbonate composition according to claim 1, characterized in that, The PFAS-free flame-retardant polycarbonate composition also includes at least one of an antioxidant, a lubricant, and a toughening agent.

7. The PFAS-free flame-retardant polycarbonate composition according to claim 6, characterized in that, Selected from at least one of (a) to (c) below: (a) The antioxidant is a phosphite antioxidant; (b) The lubricant is selected from at least one of pentaerythritol ester lubricants, stearate lubricants, paraffin lubricants, and amide lubricants; (c) The toughening agent is selected from at least one of silicon-based toughening agents, styrene block copolymers, acrylate polymers, and ethylene copolymers.

8. A method for preparing the PFAS-free flame-retardant polycarbonate composition according to any one of claims 1-7, characterized in that, The raw materials are mixed evenly, and the glass fiber is fed by side feeding and melt extrusion to prepare the PFAS-free flame-retardant polycarbonate composition.

9. The use of the PFAS-free flame-retardant polycarbonate composition according to any one of claims 1-7 in electrical appliances and consumer electronics.

10. A power charger or adapter, characterized in that, It is prepared using the PFAS-free flame-retardant polycarbonate composition according to any one of claims 1-7.

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