Flame-retardant polycarbonate and preparation method thereof

Abstract

The invention discloses flame-retardant polycarbonate and a preparation method thereof, and belongs to the technical field of high polymer materials, by introducing compound siloxane copolymerized polycarbonate and a flame retardant into polycarbonate resin, not only can the initial flame retardant property of a thin wall be guaranteed, but also the flame-retardant polycarbonate has high transparency and heat and humidity resistance, and the flame-retardant polycarbonate has good flame retardant property. And relatively high flame-retardant and transparency effects can still be maintained in a long-term humid and hot environment.

Description

Technical Field

[0001] The present invention relates to the technical field of polymer materials, and particularly relates to a flame-retardant polycarbonate and a preparation method thereof. Background Art

[0002] Polycarbonate has the characteristics of high mechanical strength and good electrical insulation. And based on the addition of flame retardants, most polycarbonate products have ideal flame retardancy, so they are widely used in many fields with high safety requirements such as electrical components, batteries, household appliances, new energy, etc. At present, polycarbonate products with a thin-wall V-0 flame retardant grade below 1 mm basically use anti-dripping agents such as PTFE as functional additives, but such additives will seriously affect the transparency of the products, and the processability of the products is significantly reduced, and the application range is limited.

[0003] At the same time, the current flame-retardant polycarbonate products have low resistance to heat and humidity. In a long-term humid and hot environment, their flame retardant performance will gradually decrease or even fail, and the transparency will further decrease. Summary of the Invention

[0004] Based on the defects existing in the prior art, the purpose of the present invention is to provide a flame-retardant polycarbonate. By introducing a compounded silicone copolymer polycarbonate and a flame retardant into the polycarbonate resin, not only can the initial flame retardant performance of the thin wall be ensured, but also it has high transparency and heat and humidity resistance, and can still maintain high flame retardant and transparency effects after a long-term humid and hot environment.

[0005] In order to achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0006] A flame-retardant polycarbonate, comprising the following components in parts by weight:

[0007] 100 parts of polycarbonate, 15-95 parts of silicone copolymer polycarbonate, 0.1-1 part of flame retardant;

[0008] The silicone copolymer polycarbonate includes silicone copolymer polycarbonate 1 and silicone copolymer polycarbonate 2;

[0009] The polycarbonate flame-retardant polycarbonate satisfies |a1 - a2| ≥ 4% and |b1 - b2| ≤ 15°C;

[0010] Wherein a1 is the silicone mass content of silicone copolymer polycarbonate 1, and b1 is the heat distortion temperature of silicone copolymer polycarbonate 1;

[0011] a2 is the silicone mass content of silicone copolymer polycarbonate 2, and b2 is the heat distortion temperature of silicone copolymer polycarbonate 2;

[0012] The flame retardant is a sulfonic acid-based flame retardant and a phenyl silicone-based flame retardant.

[0013] Polycarbonate has good mechanical strength and processing performance, but its own flame retardancy and resistance to heat and humidity are not ideal. At the same time, its transparency is easily affected by external factors and composition components, and thus whitening or fogging phenomena occur during processing or use. Therefore, in the technical solution of the present invention, in order to improve the hydrolysis resistance and flame retardancy of the product, silicone copolymer polycarbonate and sulfonic acid-based flame retardants are used to compound polycarbonate. The former significantly improves the hydrolysis resistance and oxidation resistance of polycarbonate, and the latter does not cause the transparency of the product to be weakened on the premise of achieving good flame retardancy; at the same time, the inventor noticed during the research and development process that if only one kind of silicone copolymer polycarbonate is used for compounding the product, the environmental stability resistance of the product at different stages (processing, humid and hot environment) requires the introduction of silicone copolymer polycarbonates with different amounts of silicone to achieve gradient in the hydrolysis oxidation activity of heat and humidity resistance; after setting the gradient, the compatibility and dispersibility need to be considered when different silicone copolymer polycarbonates are compounded, so the processing characteristics cannot have large differences. Therefore, in the technical solution of the present invention, the silicone copolymer polycarbonates for compounding need to control the silicone content to have a certain gap to form a gradient, and at the same time, the difference in the heat distortion temperature of the two needs to be controlled within a specific range to avoid the non-coincidence of the component homogeneity due to too large differences in processing characteristics during processing, resulting in the extrusion of the sulfonic acid-based flame retardant on the surface of the product during processing, and finally ensuring that the product can maintain high transparency and flame retardant performance whether after processing or in a humid and hot environment for a long time;

[0014] On the other hand, in order to ensure that the flame retardant can fully exert its characteristics, ensure the initial flame retardancy of the product, and at the same time the flame retardant component can maintain low migration and high compatibility stability during heat and humidity treatment, it is necessary to further introduce phenyl silicone-based flame retardants containing silicon in the sulfonic acid-based flame retardant and the PC / silicone copolymer PC system. This component can not only act as a bridge between the sulfonic acid-based flame retardant and the matrix resin, enabling high compatibility of each component, but also can coat the sulfonic acid-based flame retardant to prevent the precipitation and failure of the sulfonic acid-based flame retardant (including sulfonic acid and its salts), so that the product still has a high flame retardancy after heat and humidity treatment. If other types of flame retardants or combinations are selected, not only the transparency effect and flame retardant effect of the product cannot be guaranteed, but also the performance retention rate of the product may be at a low level after heat and humidity treatment.

[0015] Preferably, in the flame retardant polycarbonate, the weight proportion of siloxane copolymer polycarbonate is one of 15 parts, 20 parts, 25 parts, 30 parts, 40 parts, 50 parts, 60 parts, 70 parts, 80 parts, 85 parts, 90 parts, 95 parts or any two of the range values; the weight proportion of the flame retardant is one of 0.1 parts, 0.2 parts, 0.3 parts, 0.4 parts, 0.5 parts, 0.6 parts, 0.7 parts, 0.8 parts, 0.9 parts, 1 part or any two of the range values.

[0016] Preferably, in the flame retardant polycarbonate, the total mass content of polycarbonate and siloxane copolymerized polycarbonate is ≥ 90%, more preferably ≥ 95%.

[0017] Preferably, the |a1-a2|=4-15%, and / or the |b1-b2|=1-15°C.

[0018] Further preferably, the range value of |a1-a2|=4, 5, 6, 8, 10, 11, 12, 13, 13.5, 14, 14.5, 15 or any two of them.

[0019] Further preferably, the |b1-b2|=one or any two of the range values ​​of 1°C, 2°C, 4°C, 5°C, 8°C, 9°C, 10°C, 12°C, 13°C, and 15°C.

[0020] Preferably, the polycarbonate includes at least one of bisphenol A polycarbonate, bisphenol F polycarbonate, and bisphenol S polycarbonate, and more preferably bisphenol A polycarbonate.

[0021] The polycarbonate composition product of the present invention can achieve excellent moisture and heat resistance, flame retardancy and transparency with relatively low additive addition, which can not only effectively control production costs but also expand the subsequent processing range of the product, and the product has high processing plasticity.

[0022] Preferably, the siloxane mass content of the siloxane copolymer polycarbonate 1 and 2 can be measured and confirmed by but not limited to the following method: Referring to "Determination of the Content of Low Molecular Polysiloxane in Room Temperature Vulcanized Silicone Rubber by Gas Chromatography" in "Chemical Technology and Development" 2018-47-3, 5 g of the sample was ultrasonically dissolved in 20 mL of cyclohexane for 20 minutes, then condensed and refluxed at 50°C for 10 hours, 10 g of the obtained clear solution was weighed and 1 drop of n-hexadecane was added, and then the content of siloxane in the sample was determined by direct injection gas chromatography with an FID detector according to the parameter settings in the reference.

[0023] Preferably, the heat distortion temperatures of the siloxane copolymer polycarbonates 1 and 2 are tested according to ASTM D648-2007 under the condition of 1.82 MPa. During the test, the specimen (127 mm×13 mm×6.4 mm) is placed vertically on the simply supported beam bracket, a bending stress of 1.82 MPa is applied perpendicular to the edge of the specimen, and then the specimen is immersed in silicone oil. The temperature is uniformly increased at a rate of 2±0.2 °C / min while keeping the medium fully stirred. When the midpoint bending deformation of the specimen reaches 0.25 mm, the temperature at this time is immediately recorded, which is the heat distortion temperature.

[0024] Preferably, in the flame-retardant polycarbonate, the weight parts of the siloxane copolymer polycarbonate 1 and / or the siloxane copolymer polycarbonate 2 are 4 to 50 parts.

[0025] Preferably, the mass content of siloxane in the siloxane copolymer polycarbonate 1 and the siloxane copolymer polycarbonate 2 is ≥3%;

[0026] More preferably, the mass content of siloxane in the siloxane copolymer polycarbonate 1 / or the siloxane copolymer polycarbonate 2 is 6 to 20%. More preferably, it is one of 6%, 7%, 8%, 10%, 12%, 15%, 18%, 20% or the range value of any two of them.

[0027] Preferably, the heat distortion temperatures of the siloxane copolymer polycarbonate 1 and the siloxane copolymer polycarbonate 2 are ≤130 °C;

[0028] More preferably, the heat distortion temperature of the siloxane copolymer polycarbonate 1 / or the siloxane copolymer polycarbonate 2 is 105 to 125 °C. More preferably, it is one of 105 °C, 108 °C, 110 °C, 112 °C, 115 °C, 118 °C, 120 °C, 122 °C, 125 °C or the range value of any two of them.

[0029] When the siloxane copolymer polycarbonates 1 and 2 of the present invention are compounded, there is no need to specifically set the heat distortion temperature or the silicon content of each. It is only necessary to ensure that there is a gradient in the moisture-resistant hydrolysis performance of the two and the processing characteristics gap is within a certain range. Those skilled in the art can select appropriate types based on the application scenario during actual selection.

[0030] Preferably, the melt index of the siloxane copolymer polycarbonate is 1 to 15 g / 10 min according to ASTM D1238-2010 at 300 °C and 1.2 kg load.

[0031] Preferably, the melt index of the polycarbonate is 3 to 20 g / 10 min according to ASTM D1238-2010 at 300 °C and 1.2 kg load.

[0032] More preferably, the melt index at 300 °C and a load of 1.2 kg is one of 3 g / 10 min, 5 g / 10 min, 7 g / 10 min, 10 g / 10 min, 12 g / 10 min, 15 g / 10 min, 18 g / 10 min, 19 g / 10 min, 20 g / 10 min or a range value of any two of them.

[0033] More preferably, the melt index of the polycarbonate at 300 °C and a load of 1.2 kg is 7 to 15 g / 10 min.

[0034] Generally speaking, the melt index of the matrix polycarbonate in the polycarbonate composition is related to the fluidity, which in turn leads to different mechanical properties of the product. Those skilled in the art can select a polycarbonate with a suitable melt index as the matrix according to the actual mechanical requirements of the product. In the technical solution of the present invention, when the melt index of the polycarbonate is preferably within the above range, the product has better resistance to humidity and heat, and the haze of the product is lower after long-term humidity and heat treatment.

[0035] Preferably, the sulfonic acid-based flame retardant includes at least one of potassium 3-benzenesulfonylbenzenesulfonate, sodium 2,4,5-trichlorobenzenesulfonate, and HES (hydroxyethylsulfonic acid).

[0036] Preferably, the phenylsiloxane-based flame retardant includes at least one of phenylcyclosiloxane and phenylpolysilsesquioxane.

[0037] It should be noted that the specific types of the sulfonic acid-based flame retardant and the phenylsiloxane-based flame retardant described in the present invention are not limited to the above. Those skilled in the art can also select other types of sulfonate-based flame retardants and / or phenylsiloxane-based flame retardants based on the actual situation, as long as the product has the expected transparency, flame retardancy, and resistance to humidity and heat, there is no limitation.

[0038] More preferably, the mass ratio of the sulfonic acid-based flame retardant to the phenylsiloxane-based flame retardant is (9:1) to (1:1).

[0039] Preferably, the flame-retardant polycarbonate further includes 0.1 to 5 parts of functional additives or processing aids;

[0040] Further preferably, the functional aids include, but are not limited to, at least one of antistatic agents and antibacterial agents, and the processing aids include at least one of lubricants and mold release agents. Those skilled in the art can add various different functional aids or processing aids according to actual needs without affecting the transparency, flame retardancy, and moisture and heat resistance of the products of the present invention. For example, in order to also give the product antistatic properties during application, those skilled in the art can add antistatic agents to the product; in order to make the demolding effect of the product better during processing, those skilled in the art can add a small amount of lubricants or mold release agents to lubricate the product.

[0041] Another object of the present invention also lies in providing a method for preparing the flame-retardant polycarbonate, comprising the following steps:

[0042] Adding each component into a screw extruder for melt extrusion and pelletizing to obtain the flame-retardant polycarbonate.

[0043] Preferably, the temperature zones of the screw extruder are set as follows: zone 1: 270 - 280 °C, zone 2: 270 - 280 °C, zone 3: 280 - 260 °C, zone 4: 280 - 260 °C, zone 5: 280 - 260 °C, zone 6: 270 - 260 °C, zone 7: 270 - 260 °C, zone 8: 265 - 250 °C, zone 9: 260 - 250 °C, zone 10: 260 - 250 °C, the screw rotation speed is 400 - 600 rpm, and the screw length-diameter ratio is (45 - 50):1.

[0044] The method for preparing the flame-retardant polycarbonate of the present invention is simple, has low requirements for equipment, and can achieve industrial-scale production.

[0045] Another object of the present invention lies in providing the application of the flame-retardant polycarbonate in the preparation of transparent electronic device components.

[0046] More preferably, the transparent electronic device components include an electronic device housing and an electronic device insulating sheath.

[0047] Another object of the present invention lies in providing a transparent electronic device component, which comprises the flame-retardant polycarbonate of the present invention.

[0048] The flame-retardant polycarbonate of the present invention is based on the co - blending of a specific type of silicone - oxygen - alkane copolymer polycarbonate and a flame retardant, which can ensure high component compatibility and chemical inertness of each component at all stages from product processing to handling in a humid and hot environment. This enables the product to have persistent stability in terms of transparency and flame retardancy on the premise of a relatively high initial level, and is very suitable for transparent electronic device components that not only require transparency for observing the internal circuit conditions but also need to have moisture and heat resistance and flame retardancy.

[0049] The beneficial effects of the present invention are as follows. The present invention provides a flame-retardant polycarbonate. By introducing a compounded silicone copolymer polycarbonate and a flame retardant into the polycarbonate resin, not only can the initial flame-retardant performance of the thin-walled structure be ensured, but also high transparency and resistance to heat and humidity are achieved. Even after being in a long-term humid and hot environment, relatively high flame-retardant and transparency effects can still be maintained. Detailed Embodiments

[0050] To better illustrate the objectives, technical solutions, and advantages of the present invention, the following will further explain the present invention in combination with specific examples and comparative examples. The purpose is to understand the content of the present invention in detail, rather than limiting the present invention. All other examples obtained by those of ordinary skill in the art without creative efforts fall within the protection scope of the present invention. The experimental reagents and instruments involved in the implementation of the present invention are all common ordinary reagents and instruments unless otherwise specified.

[0051] Examples 1 - 16

[0052] Examples of the flame-retardant polycarbonate of the present invention and its preparation method. The component composition of the flame-retardant polycarbonate is shown in Table 1.

[0053] The preparation method of the flame-retardant polycarbonate includes the following steps:

[0054] Mix all components evenly, and then melt and extrude them into pellets in a twin-screw extruder to obtain the flame-retardant polycarbonate.

[0055] When the components are melt-extruded, the temperature zones of the screw extruder are set as follows: Zone 1: 280°C, Zone 2: 280°C, Zone 3: 270°C, Zone 4: 270°C, Zone 5: 270°C, Zone 6: 265°C, Zone 7: 265°C, Zone 8: 260°C, Zone 9: 250°C, Zone 10: 250°C. The screw rotation speed is 500 rpm, and the screw length-diameter ratio is 48:1.

[0056] Comparative Examples 1 - 11

[0057] The differences between each comparative example and the example are only in the types and ratios of the components, as shown in Table 2.

[0058] Among the components of each example and comparative example,

[0059] The polycarbonate 1 is PC2100 produced by Wanhua Chemical, and its melt index at 300°C and 1.2 kg load is 10 g / 10 min;

[0060] The polycarbonate 2 is PC7030PJ produced by Mitsubishi Gas, and its melt index at 300°C and 1.2 kg load is 3 g / 10 min;

[0061] The polycarbonate 3 is PC2070 produced by Wanhua Chemical, with a melt index of 7 g / 10 min at 300 °C and a load of 1.2 kg;

[0062] The polycarbonate 4 is PCS3000VR produced by Mitsubishi Gas, with a melt index of 15 g / 10 min at 300 °C and a load of 1.2 kg;

[0063] The polycarbonate 5 is PC2220 produced by Wanhua Chemical, with a melt index of 19 g / 10 min at 300 °C and a load of 1.2 kg;

[0064] The silicone copolymer polycarbonate 1 is PC8000-05 produced by LG Chemical, with a silicone content of 6.5 wt% and a heat distortion temperature of 118 °C;

[0065] The silicone copolymer polycarbonate 2 is PC8010-10 produced by LG Chemical, with a silicone content of 10 wt% and a heat distortion temperature of 108 °C;

[0066] The silicone copolymer polycarbonate 3 is PCFG1760 produced by Idemitsu Kosan of Japan, with a silicone content of 6 wt% and a heat distortion temperature of 125 °C;

[0067] The silicone copolymer polycarbonate 4 is PCS1240 produced by Wanhua Chemical, with a silicone content of 6 wt% and a heat distortion temperature of 120 °C;

[0068] The silicone copolymer polycarbonate 5 is PCS2060 produced by Wanhua Chemical, with a silicone content of 20 wt% and a heat distortion temperature of 116 °C;

[0069] The flame retardant 1 is KSS-FR, potassium 3-benzenesulfonylbenzenesulfonate, produced by Arichem of the United States;

[0070] The flame retardant 2 is sodium 2,4,5-trichlorobenzenesulfonate produced by Hubei Xinyuhong Biomedical Technology Co., Ltd.;

[0071] The flame retardant 3 is a sulfonate flame retardant, HES, produced by Arichem;

[0072] The flame retardant 4 is WSFR-BDP-N2, bisphenol A-bis(diphenyl phosphate), produced by Wansheng;

[0073] The flame retardant 5 is SP206, octaphenylcyclotetrasiloxane, produced by Liaoning Xinbang New Materials Co., Ltd.;

[0074] The flame retardant 6 is POSS, octaphenyl polyhedral oligomeric silsesquioxane, produced by Hubei Maidehao Biotechnology Co., Ltd.;

[0075] The flame retardant 7 is Dow Corning 40-001, a polysiloxane.

[0076] Unless otherwise specified, the component raw materials used in the examples and comparative examples of the present invention are all commercially available raw materials, and the component raw materials used in each parallel experiment are the same.

[0077] Among them, a represents the difference in the siloxane content of the two siloxane copolymer polycarbonate components in each example or comparative example, and b represents the difference in the heat distortion temperature of the two siloxane copolymer polycarbonate components in each example or comparative example.

[0078] Table 1

[0079]

[0080] Table 2

[0081]

[0082]

[0083] In order to verify the performance of the polypropylene composition of the present invention, the products prepared in each example and comparative example were subjected to the following performance tests, and the specific steps are as follows:

[0084] (1) After drying the products of each example and comparative example at 120 °C for 4 h, they were pre-injected into square plates with a thickness of 100 * 100 * 1 mm at 280 °C. Subsequently, according to the standard of GB2680-1944, a visible light transmittance meter was used to test the visible light transmittance and haze. Then, the samples were placed in a constant temperature and humidity chamber at 85 °C and a relative humidity of 85% and left standing for 1000 h. The visible light transmittance and haze were tested again using the same method. The higher the visible light transmittance and the lower the haze, the better the transparency of the product.

[0085] (2) After drying the products of each example and comparative example at 120 °C for 4 h, they were pre-injected into test specimens with a thickness of 127 * 13 * 1 mm at 280 °C. Subsequently, the test standard was UL94. The specimens were placed in an environment with a temperature of 23 ± 2 °C and a humidity of 50 ± 5% for temperature and humidity adjustment for 48 h. Then, according to the UL 94 vertical burning standard, the specimens were subjected to two 10 ± 1 s flame applications, and the time t1 and t2 required for the specimen to extinguish after each flame application and whether there was a situation where dripping ignited the cotton wool below were recorded. Five specimens were tested for each sample. If the total burning time of the five specimens t1 + t2 did not exceed 50 s and there was no dripping ignition phenomenon, it was judged as V-0; if there was no dripping ignition and the total burning time was between 50 - 250 s, it was judged as V-1; if there was a dripping ignition and the total burning time was between 50 - 250 s, it was judged as V-2.

[0086] The test results are shown in Tables 3 and 4.

[0087] Table 3

[0088]

[0089] Table 4

[0090]

[0091] As can be seen from Table 3 and Table 4, the flame-retardant polycarbonate described in the present invention has ideal flame retardancy, transparency and resistance to heat and humidity. Specifically, the initial light transmittance of the product can reach 85% or more, the haze can be maintained below 1.5%, and the initial flame retardant grade is V-0; after long-term heat and humidity treatment, the light transmittance can still be maintained at 84% or more, the haze is within 2.2%, and the flame retardant grade remains unchanged, with excellent comprehensive performance. This is mainly due to the introduction of a specific compounded siloxane copolymer polycarbonate and a specific combination of flame retardants into the polycarbonate resin matrix of the product described in the present invention, and excellent synergistic compounding effects can be achieved among the components. In contrast, only one kind of siloxane copolymer polycarbonate was used for compounding in the products described in Comparative Examples 1 and 2, and it was impossible to achieve a good environmental resistance activity gradient. At the same time, it was difficult to achieve good flame retardant dispersion and compatibility effects in the obtained composite resin matrix. Not only the initial flame retardancy could not be guaranteed, but also the transparency and flame retardancy of the products decreased significantly after heat and humidity treatment. Although Comparative Examples 3-8 used compounded siloxane copolymer polycarbonates, and the types were the same as those of the products in the examples, due to the gradient setting during compounding not meeting the requirements defined in the present invention, the flame retardant grade of some products could only reach V-2 at the initial state, and after heat and humidity treatment, the light transmittance of the products was only 81% at the lowest, and the haze reached 4.2% at the highest, and the flame retardant performance was also significantly weakened; only sulfonic acid-based flame retardants were used as flame retardants in the products of Comparative Example 9, and the types of compounded flame retardants in the products of Comparative Examples 10-11 were not the same as those defined in the products of the present invention. The initial flame retardant grades of the products were relatively low. Most importantly, these inappropriate flame retardants would seriously affect the heat and humidity resistance of the products. After heat and humidity treatment, the light transmittance of the products was only 79% at the lowest, and the haze even reached 11.5% at the highest.

[0092] It can be seen from Example 1 and Examples 8-11 that in addition to the compounding selection of siloxane copolymer polycarbonates and the specific combination of flame retardants, when the melt index of the matrix polycarbonate changes, the fluidity changes, and there are certain differences in the component creep degree of the products in the processing and heat and humidity environments. When the melt index of the polycarbonate is further preferably 7-15 g / 10 min, the initial haze of the products is lower, but all the products are still superior to the control products of each comparative example.

[0093] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit the protection scope of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A flame retardant polycarbonate, characterized in that: The composition comprises the following components in parts by weight: 100 parts of polycarbonate, 15-95 parts of siloxane copolymer polycarbonate, 0.1-1 part of flame retardant; The siloxane copolymer polycarbonate comprises siloxane copolymer polycarbonate 1 and siloxane copolymer polycarbonate 2; The flame retardant polycarbonate satisfies |a1-a2|≥4% and |b1-b2|≤15°C; Wherein a1 is the siloxane mass content of the siloxane copolymer polycarbonate 1, and b1 is the heat deformation temperature of the siloxane copolymer polycarbonate 1; a2 is the siloxane mass content of the siloxane copolymer polycarbonate 2, and b2 is the thermal deformation temperature of the siloxane copolymer polycarbonate 2; The flame retardant is a sulfonic acid flame retardant and a phenylsiloxane flame retardant.

2. The flame retardant polycarbonate according to claim 1, characterized in that: The siloxane mass content of the siloxane copolymer polycarbonate 1 and the siloxane copolymer polycarbonate 2 is ≥3%; and / or the heat deformation temperature of the siloxane copolymer polycarbonate 1 and the siloxane copolymer polycarbonate 2 is ≤130°C.

3. The flame retardant polycarbonate according to claim 1, characterized in that: The |a1-a2|=4-15%, and / or the |b1-b2|=1-15°C.

4. The flame retardant polycarbonate according to claim 1, characterized in that: The sulfonic acid flame retardant includes at least one of potassium 3-phenylsulfonylbenzenesulfonate, sodium 2,4,5-trichlorobenzenesulfonate, and isethionic acid, and / or the phenylsiloxane flame retardant includes at least one of phenylcyclosiloxane and phenyl polysilsesquioxane.

5. The flame retardant polycarbonate according to claim 1, characterized in that: The mass ratio of the sulfonic acid flame retardant to the phenylsiloxane flame retardant is (9:1) to (1:1).

6. The flame retardant polycarbonate according to claim 1, characterized in that: The polycarbonate has a melt index of 3 to 20 g / 10 min at 300° C. and a load of 1.2 kg, and / or the siloxane copolymer polycarbonate has a melt index of 1 to 15 g / 10 min at 300° C. and a load of 1.2 kg.

7. The method for preparing the flame retardant polycarbonate according to any one of claims 1 to 6, characterized in that: The following steps are involved: The various components are added into a screw extruder for melt extrusion and granulation to obtain the flame retardant polycarbonate.

8. Use of the flame retardant polycarbonate according to any one of claims 1 to 6 in the preparation of transparent electronic device parts.

9. A transparent electronic device component, characterized in that: The invention comprises the flame retardant polycarbonate according to any one of claims 1 to 6.

10. The transparent electronic device component according to claim 9, characterized in that: The transparent electronic device parts include an electronic device housing and an electronic device insulating sheath.

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