Needle-flame-resistant flame-retardant polycarbonate composition and preparation method thereof

Abstract

The invention provides a needle-flame-resistant flame-retardant polycarbonate composition and a preparation method thereof, and relates to the technical field of flame-retardant polycarbonate materials. The needle-flame-resistant flame-retardant polycarbonate composition is prepared from the following raw material components in parts by weight: 100 parts of polycarbonate and 1 to 15 parts of hyperbranched flame retardant, the hyperbranched flame retardant is obtained by reaction of reaction raw materials containing double-terminal hydroxyl polysiloxane and phosphorus oxychloride. The hyperbranched flame retardant is added into polycarbonate, the characteristics of polysiloxane and organophosphate are combined, and the polycarbonate material has good flame retardance and meanwhile achieves needle flame resistance flame retardance and UL-94 vertical combustion V-0 grade.

Description

Technical Field

[0001] The invention belongs to the technical field of flame-retardant polycarbonate materials and relates to a needle-flame-resistant flame-retardant polycarbonate composition and a preparation method thereof. Background Art

[0002] Polycarbonate, referred to as PC, has good properties, such as easy processing, high transparency, high mechanical strength, etc., and is widely used in many fields, but its flame retardant performance is poor, which affects its safety during application. Therefore, it is generally necessary to add flame retardants to polycarbonate to improve its flame retardancy. Flame retardants commonly used in polycarbonate include halogen flame retardants, phosphate flame retardants, inorganic flame retardants and silicone flame retardants. In order to further improve the flame retardant performance of flame retardants, two or more flame retardants are generally compounded and used. There are physical compounding methods and chemical compounding methods, or there are also hyperbranched flame retardants with hyperbranched structures. Chinese patent CN114479407A discloses a thin-walled flame retardant polycarbonate material, in which a compound flame retardant, a phosphorus flame retardant and a carbon-forming agent are added to the polycarbonate. The compound flame retardant is composed of potassium diphenylsulfone sulfonate, potassium perfluorobutyl sulfonate and octaphenyl cage-shaped silsesquioxane, and the carbon-forming agent is a hyperbranched macromolecular flame retardant carbon-forming agent. The above method requires the combined use of a compound flame retardant and a hyperbranched flame retardant.

[0003] Flame retardancy testing methods with relatively high requirements include the needle flame test and the UL-94 vertical burn test (for example, achieving a V-0 rating). However, these two flame retardancy tests have different methods and requirements, and the test results are not equivalent, and there are even certain contradictions. To achieve vertical flame retardancy, plastic products generally add anti-drip agents (such as PTFE). However, excessive levels of anti-drip agents will cause the melted plastic product to shrink during combustion, causing the plastic to burn through, failing to meet the needle flame flame retardancy requirements. However, there are currently few reports that PC can meet both the needle flame test requirements and the UL-94 vertical burn test V-0 rating after flame retardancy enhancement. Summary of the Invention

[0004] In order to solve the above technical problems, the present invention provides a needle flame retardant polycarbonate composition and a preparation method thereof.

[0005] The technical solutions of the present invention are as follows:

[0006] A needle flame retardant polycarbonate composition, comprising, by weight, 100 parts of polycarbonate and 1-15 parts of a hyperbranched flame retardant;

[0007] The hyperbranched flame retardant is obtained by reacting reaction raw materials containing dihydroxyl-terminated polysiloxane and phosphorus oxychloride.

[0008] Preferably, the molar ratio of the dihydroxy-terminated polysiloxane to the phosphorus oxychloride is 2.8-3.8:2.

[0009] Preferably, the structure of the dihydroxylated polysiloxane is as shown in the following formula (1):

[0010] HOR 1 SiMe2O(SiOMeR 2 ) n SiMe2R 1 OH(1)

[0011] Among them, R 1 is absent, C2-C6 divalent alkyl, substituted C3-C8 divalent alkyl, R 2 Selected from C1-C4 alkyl, C6-C14 aromatic or C5-C12 cycloalkyl, Me is methyl, and n=3-20.

[0012] More preferably, when the molar ratio of the dihydroxy-terminated polysiloxane to the phosphorus oxychloride is 3.2-3.8:2, the reaction raw materials further comprise a maleic anhydride grafted polymer.

[0013] More preferably, the hyperbranched flame retardant is obtained by reacting the dihydroxy-terminated polysiloxane with the phosphorus oxychloride and then reacting with the maleic anhydride grafted polymer.

[0014] More preferably, the molar ratio of the number of moles of maleic anhydride groups in the maleic anhydride grafted polymer to the dihydroxy-terminated polysiloxane is 0.05-0.2:1.

[0015] More preferably, the grafting rate of the maleic anhydride grafted polymer is 1-8 wt %.

[0016] Further preferably, the maleic anhydride grafted polymer is selected from one or two of maleic anhydride grafted PE, maleic anhydride grafted PP, maleic anhydride grafted POE, maleic anhydride grafted EVA, maleic anhydride grafted ABS, maleic anhydride grafted SEBS and maleic anhydride grafted SAN, and combinations thereof.

[0017] Preferably, the raw material components further comprise one or a combination of two or more of 0.2-1 parts of antioxidant, 0.2-1 parts of anti-ultraviolet agent, 0.1-2 parts of pigment and 0-0.1 parts of anti-dripping agent.

[0018] A method for preparing the needle flame retardant polycarbonate composition according to any of the above embodiments comprises mixing the raw material components uniformly, adding the components into a screw extruder, melting and extruding, and forming the components.

[0019] The beneficial effects of the present invention are:

[0020] (1) The hyperbranched flame retardant of the present invention combines the flame retardant properties of silicone and organophosphate, and adopts a hyperbranched structure to synergistically exert the flame retardant effects of the two flame retardants, has better flame retardant properties, and enables PC to simultaneously meet the needle flame retardant requirements and the UL-94 vertical combustion V-0 grade.

[0021] (2) When maleic anhydride graft copolymer is further introduced into the hyperbranched flame retardant, the compatibility of the hyperbranched flame retardant with polycarbonate can be further improved and the flame retardancy can be further enhanced.

[0022] (3) The polysiloxane segments in the hyperbranched structure of the present invention can further improve the impact resistance and low-temperature resistance of polycarbonate. DETAILED DESCRIPTION

[0023] The technical solution of the present invention is further illustrated and described below through specific implementation methods.

[0024] In order to improve the flame retardant properties of polycarbonate and enhance its safety in application, the present invention provides a needle flame retardant polycarbonate composition, wherein the raw material components, calculated by weight, comprise: 100 parts of polycarbonate and 1-15 parts of a hyperbranched flame retardant;

[0025] The hyperbranched flame retardant is obtained by reacting reaction raw materials including dihydroxyl-terminated polysiloxane and phosphorus oxychloride.

[0026] Hyperbranched flame retardants have a special structure and have good flame retardant properties for polycarbonate at low dosages. The present invention adopts a hyperbranched flame retardant that combines the flame retardant properties of polysiloxanes and the flame retardant properties of organophosphates. In addition, the hyperbranched flame retardant has a hyperbranched structure and has a better flame retardant effect than separate polysiloxanes and separate organophosphates. The P-Cl in phosphorus oxychloride has a high reactivity and can react with the terminal hydroxyl groups of dihydroxy-terminated polysiloxanes to obtain a hyperbranched structure. There are three P-Cl groups (A3) in the phosphorus oxychloride structure and two OH groups (B2) in the dihydroxy-terminated polysiloxane structure. The resulting hyperbranched flame retardant has an "A3+B2" structure.

[0027] For example, the weight percentage of the hyperbranched flame retardant in the polycarbonate composition can be 1 part, 2 parts, 3 parts, 4 parts, 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, 10 parts, 11 parts, 12 parts, 13 parts, 14 parts, 15 parts, etc., and further, the weight percentage can be 3-15 parts.

[0028] In certain embodiments, the mol ratio of dihydroxy polysiloxane and phosphorus oxychloride is 2.8-3.8:2. The mol ratio of dihydroxy polysiloxane and phosphorus oxychloride is within the above range, and a hyperbranched flame retardant with a hyperbranched structure can be obtained. For example, the mol ratio of dihydroxy polysiloxane and phosphorus oxychloride can be any value in 2.8:2, 2.9:2, 3:2, 3.1:2, 3.2:2, 3.3:2, 3.4:2, 3.5:2, 3.6:2, 3.7:2, 3.8:2 etc., without particular restrictions. Further, the mol ratio of dihydroxy polysiloxane and phosphorus oxychloride can be 3-3.8:2, which can react the P-Cl group in phosphorus oxychloride more completely, and avoids Cl from remaining in the hyperbranched flame retardant, causing halogen content to exceed the standard or unstable product quality in subsequent products.

[0029] In some embodiments, the structure of the dihydroxylated polysiloxane is shown in the following formula (1):

[0030] HOR 1 SiMe2O(SiOMeR 2 ) n SiMe2R 1 OH(1)

[0031] Among them, R 1 is absent, C2-C6 divalent alkyl, substituted C3-C8 divalent alkyl, R 2 Selected from C1-C4 alkyl, C6-C14 aromatic or C5-C12 cycloalkyl, Me is methyl, and n=3-20.

[0032] In the present invention, the bihydroxyl-terminated polysiloxane is not particularly limited. Considering the reactivity of the terminal hydroxyl groups, the bihydroxyl-terminated polysiloxane may be a bihydroxyalkyl polysiloxane, such as a bihydroxypropyl polydimethylsiloxane (R in the above formula (1) is 1 -(CH2)3, R 2 is methyl), double-terminal hydroxypropyl polymethylphenylsiloxane (R in the above formula (1) 1 -(CH2)3, R 2 is a combination of methyl and phenyl groups, the phenyl group content can be 5-20 mol%), double-terminal hydroxybutyl polydimethylsiloxane (R in the above formula (1) 1 -(CH2)4, R 2is methyl), etc. The degree of polymerization n should not be too high. If it is too high, the activity of the terminal hydroxyl group will be reduced and the content of the organic phosphate in the hyperbranched flame retardant will be too low. For example, n can be any value among 3, 3.5, 5, 6.5, 7, 7.5, 8, 9.5, 10, 10.5, 11, 12, 12.5, 13, 14, 15, 16.5, 17, 17.5, 18, 18.5, 20, etc. There is no special restriction on the source of the double-terminal hydroxyl polysiloxane. It can be directly obtained from the market or prepared according to the existing technology, which is known to those skilled in the art. For example, 1,3-dihydroxypropyl-1,1,3,3-tetramethyldisiloxane is used as the end-capping agent, and the siloxane ring body (such as octamethylcyclotetrasiloxane D4, tetramethyltetraphenylcyclotetrasiloxane D4) is used. Ph The above-mentioned bihydroxy polysiloxane can also be prepared by using a strong acid (such as concentrated sulfuric acid, acidic clay, strong acid cation exchange resin, trifluoromethylbenzenesulfonic acid, etc.) as a catalyst to carry out a ring-opening polymerization reaction at a certain temperature (such as 50-90°C), removing the acid catalyst (such as filtration and neutralization), and then heating to a higher temperature (such as 135-140°C) to decompose and destroy the catalyst, and then removing low-boiling substances under reduced pressure to obtain the product.

[0033] In some embodiments, when the molar ratio of the dihydroxyl-terminated polysiloxane to phosphorus oxychloride is 3.2-3.8:2, the reaction raw materials further include a maleic anhydride grafted polymer. When the molar ratio of the dihydroxyl-terminated polysiloxane to phosphorus oxychloride is 3.2-3.8:2, the dihydroxyl-terminated polysiloxane is in excess relative to the phosphorus oxychloride, the phosphorus oxychloride reacts completely, and the resulting hyperbranched flame retardant has a relatively small molecular weight. Furthermore, the end groups contain a certain amount of hydroxyl groups, which can react with other compounds or polymers, further optimizing the performance of the hyperbranched flame retardant, such as further improving its compatibility with polycarbonate.

[0034] When the molar ratio of the dihydroxy-terminated polysiloxane to phosphorus oxychloride is 3.2-3.8:2, in some embodiments, a hyperbranched flame retardant is obtained by reacting the dihydroxy-terminated polysiloxane with phosphorus oxychloride and then reacting it with a maleic anhydride grafted polymer. The maleic anhydride grafted polymer has good compatibility with polycarbonate, and the maleic anhydride groups can also chemically react with hydroxyl groups, carboxyl groups, etc. in the polycarbonate, allowing the hyperbranched flame retardant to be chemically bonded to the polycarbonate. As described above, the hyperbranched flame retardant contains a certain amount of hydroxyl groups at its end groups. After further reaction with a maleic anhydride grafted polymer, the maleic anhydride grafted polymer is introduced into the structure of the hyperbranched flame retardant. Since the maleic anhydride groups can also react with polycarbonate, the hyperbranched flame retardant can be chemically bonded to the polycarbonate. While maintaining good flame retardancy, it can also bring other performance optimizations to the polycarbonate. For example, the polysiloxane structure with good flexibility and low-temperature resistance can improve the impact resistance and low-temperature resistance of the polycarbonate composition. Compared with physically mixing the hyperbranched flame retardant into the polycarbonate, chemically grafting the hyperbranched flame retardant into the polycarbonate has more outstanding performance. Although the addition of maleic anhydride grafted polymer to the hyperbranched flame retardant reduces the effective content of polysiloxane and organic phosphate in the hyperbranched flame retardant, and the flame retardant performance decreases to a certain extent when the same weight ratio of hyperbranched flame retardant is added, the flame retardant performance is still good, and other properties of polycarbonate can be improved, and the flame retardant performance can be compensated and improved by adding more hyperbranched flame retardant.

[0035] When the molar ratio of the dihydroxy-terminated polysiloxane to phosphorus oxychloride is 3.2-3.8:2, in some embodiments, the molar ratio of the number of maleic anhydride groups in the maleic anhydride grafted polymer to the dihydroxy-terminated polysiloxane is 0.05-0.2:1. If the molar ratio of the maleic anhydride groups in the maleic anhydride grafted polymer is too low, most or all of the maleic anhydride groups will react, weakening or even rendering the maleic anhydride grafted polymer ineffective. If the molar ratio of the maleic anhydride groups in the maleic anhydride grafted polymer is too high, it is equivalent to introducing too much maleic anhydride grafted polymer, resulting in a decrease in the flame retardant properties of the polycarbonate composition. For example, the molar ratio of the number of moles of maleic anhydride groups in the maleic anhydride grafted polymer to the dihydroxy-terminated polysiloxane can be any value among 0.05:1, 0.07:1, 0.08:1, 0.1:1, 0.12:1, 0.14:1, 0.15:1, 0.16:1, 0.18:1, 0.2:1, etc.

[0036] In some embodiments, the grafting rate of the maleic anhydride grafted polymer is 1-8wt%. The grafting rate of the maleic anhydride grafted polymer refers to the ratio of the weight of the maleic anhydride monomer successfully grafted onto the polymer backbone after the grafting reaction to the weight of the initial polymer. For example, the grafting rate can be any value in the range of 1wt%, 1.5wt%, 2wt%, 2.5wt%, 3wt%, 3.5wt%, 4wt%, 4.5wt%, 5wt%, 5.5wt%, 6wt%, 6.5wt%, 7wt%, 7.5wt%, 8wt%, etc., without particular limitation.

[0037] In some embodiments, the maleic anhydride grafted polymer is selected from one or two of maleic anhydride grafted PE (PE-g-MAH), maleic anhydride grafted PP (PP-g-MAH), maleic anhydride grafted POE (POE-g-MAH), maleic anhydride grafted EVA (EVA-g-MAH), maleic anhydride grafted ABS (ABS-g-MAH), maleic anhydride grafted SEBS (SEBS-g-MAH) and maleic anhydride grafted SAN (SAN-g-MAH) and combinations thereof. These maleic anhydride grafted polymers can be directly obtained from the market, such as Coais Chemical Co., Ltd., Nanjing Feiteng New Material Technology Co., Ltd., etc.

[0038] In some embodiments, the raw material components further include one or a combination of two or more of 0.2-1 parts of an antioxidant, 0.2-1 parts of an anti-ultraviolet agent, 0.1-2 parts of a pigment, and 0-0.1 parts of an anti-dripping agent. Antioxidants can be directly obtained from the market, such as Antioxidant 1010 and Antioxidant 168; anti-ultraviolet agents can be directly obtained from the market, such as Anti-ultraviolet agents UV327, UV328, and UV-P; pigments can be directly obtained from the market, such as iron oxide red, phthalocyanine blue, and phthalocyanine green; and anti-dripping agents can be directly obtained from the market, such as polytetrafluoroethylene powder, silicone resin powder, and silicone rubber powder.

[0039] The present invention also provides a method for preparing the needle-flame-resistant, flame-retardant polycarbonate composition described in any of the aforementioned embodiments. The method comprises uniformly mixing the raw material components, adding the components to a screw extruder, and then melt-extruding and molding the components. Specifically, the raw material components are pre-dried at 90-120°C to a water content of no more than 0.1wt%. The screw extruder is a twin-screw extruder with a melt temperature of 230-280°C and an extrusion head temperature of 270°C.

[0040] The polycarbonate composition obtained by the present invention has good flame retardancy, impact resistance and the like, and can be used in various fields such as automotive parts, electronic products, medical equipment, sports equipment, aerospace and the like.

[0041] The technical solution of the present invention is further described and illustrated below based on various preparation examples and embodiments.

[0042] Preparation Example 1-4 Preparation of Hyperbranched Flame Retardant

[0043] Preparation Example 1

[0044] Under nitrogen protection, 0.1 mol of phosphorus oxychloride and 0.31 mol of triethylamine were added to 400 ml of anhydrous tetrahydrofuran and cooled in an ice-water bath. A dihydroxypropyl polydimethylsiloxane solution (0.152 mol of dihydroxypropyl polydimethylsiloxane (n=5.5 in the above formula (1)) dissolved in 300 ml of anhydrous tetrahydrofuran) was added dropwise. After the addition, stirring was continued in an ice-water bath for 6 h, then stirred at room temperature for 2 h, then heated to 50° C. and reacted for 5 h. The mixture was cooled to room temperature and filtered. The filtrate was concentrated to about 200 ml and then added to 2000 ml of methanol. The precipitate was collected and dried in an oven at 50° C. overnight to obtain a hyperbranched flame retardant, which was recorded as R-1.

[0045] Preparation Example 2

[0046] Under nitrogen protection, 0.1 mol of phosphorus oxychloride and 0.31 mol of triethylamine were added to 400 ml of anhydrous tetrahydrofuran and cooled in an ice-water bath. A solution of bihydroxypropyl polymethylphenylsiloxane (n = 12.7 in the above formula (1), and the molar ratio of phenyl groups is 15%) (0.16 mol of bihydroxypropyl polydimethylsiloxane dissolved in 300 ml of anhydrous tetrahydrofuran) was added dropwise. After the addition, stirring was continued in an ice-water bath for 6 h, and then stirred at room temperature for 2 h. The temperature was then raised to 50° C. and reacted for 5 h. The mixture was cooled to room temperature and filtered. The filtrate was concentrated to 300 ml and then added to 3000 ml of methanol. The liquid was separated and the product was collected and dried in an oven at 50° C. overnight to obtain a hyperbranched flame retardant, which was recorded as R-2.

[0047] Preparation Example 3

[0048] POE-g-MAH (grafting rate 2.2 wt%) and the hyperbranched flame retardant R-2 obtained in Preparation Example 2 (the molar ratio of maleic anhydride group to double-terminated hydroxypropyl polydimethylsiloxane is 0.05:1) are dried to a water content of no more than 0.1 wt%, mixed evenly, and added to a twin-screw extruder. Melt extrusion and granulation are performed at 160-190 ° C to obtain hyperbranched flame retardant R-3.

[0049] Preparation Example 4

[0050] Under nitrogen protection, 0.1 mol of phosphorus oxychloride and 0.31 mol of triethylamine were added to 400 ml of anhydrous tetrahydrofuran and cooled in an ice-water bath. A solution of bihydroxybutyl polydimethylsiloxane (n=18.1 in the above formula (1)) (0.19 mol of bihydroxybutyl polydimethylsiloxane dissolved in 500 ml of anhydrous tetrahydrofuran) was added dropwise. After the addition, stirring was continued in an ice-water bath for 6 h, and then stirred at room temperature for 2 h. The temperature was then raised to 50° C. and reacted for 3 h. The mixture was cooled to room temperature and filtered. The filtrate was concentrated to about 400 ml and then added to 5000 ml of methanol. The liquid was separated and the product was collected and dried in an oven at 50° C. overnight to obtain a hyperbranched intermediate.

[0051] The hyperbranched intermediate and ABS-g-MAH (grafting rate 4.5 wt%) (molar ratio of maleic anhydride group to double-terminated hydroxypropyl polydimethylsiloxane is 0.2:1) were dried to a water content of no more than 0.1 wt%, mixed evenly, and then added to a twin-screw extruder. Melt extrusion and granulation were performed at 160-190° C. to obtain hyperbranched flame retardant R-4.

[0052] Example 1

[0053] The polycarbonate composition consists of 2000 g of polycarbonate and 20 g of the hyperbranched flame retardant R-1 of Preparation Example 1.

[0054] The polycarbonate and hyperbranched flame retardant R-1 were dried at 110° C. to a water content of less than 0.1 wt %, mixed evenly, and then added into a twin-screw extruder for melting at 230-280° C., cooled, and pelletized to obtain a polycarbonate composition.

[0055] Example 2

[0056] The difference between this embodiment and embodiment 1 is that in embodiment 1, the amount of hyperbranched flame retardant R-1 is adjusted from 20 g to 60 g, while the other steps remain unchanged.

[0057] Example 3

[0058] The difference between this embodiment and embodiment 1 is that in embodiment 1, the amount of hyperbranched flame retardant R-1 is adjusted from 20 g to 100 g, while the remaining steps remain unchanged.

[0059] Comparative Example 1

[0060] The difference between this comparative example and Example 3 is that in Example 3, the hyperbranched flame retardant R-1 is replaced with 100 g of DOPO. The other steps remain unchanged.

[0061] Example 4

[0062] The polycarbonate composition consists of 2000 g of polycarbonate and 160 g of the hyperbranched flame retardant R-2 of Preparation Example 2.

[0063] Prepare according to the preparation method of Example 1.

[0064] Example 5

[0065] The difference between this embodiment and embodiment 4 is that in embodiment 4, the hyperbranched flame retardant R-2 is replaced by an equal weight of the hyperbranched flame retardant R-3. The remaining steps remain unchanged.

[0066] Comparative Example 2

[0067] The difference between this comparative example and Example 4 is that in Example 4, the hyperbranched flame retardant R-2 is replaced by an equal weight of DOPO. The remaining steps remain unchanged.

[0068] Example 6

[0069] The difference between this example and Example 4 is that in Example 4, the hyperbranched flame retardant R-2 is replaced with 220 g of hyperbranched flame retardant R-3. The remaining steps remain unchanged.

[0070] Example 7

[0071] The difference between this example and Example 4 is that in Example 4, the hyperbranched flame retardant R-2 is replaced with 300 g of hyperbranched flame retardant R-4. The remaining steps remain unchanged.

[0072] Example 8

[0073] The polycarbonate composition is composed of 2000 g of polycarbonate, 160 g of the hyperbranched flame retardant R-3 of Preparation Example 3, 6 g of the anti-ultraviolet agent UV327, 8 g of the antioxidant 168 and 0.5 g of anti-dripping agent polytetrafluoroethylene powder.

[0074] Prepare according to the preparation method of Example 1.

[0075] Example 9

[0076] The difference between this example and Example 8 is that in Example 8, the hyperbranched flame retardant R-3 in Preparation Example 3 is replaced by 160 g of the hyperbranched flame retardant R-1 in Preparation Example 1. The remaining steps remain unchanged.

[0077] Needle flame retardancy test: The test is conducted in accordance with the method of GB / T 5169.5-2020. The thickness of the color plate made of PC is 1mm. The combustion of the polycarbonate composition is observed after 60 seconds to check whether the color plate has perforations or cracks and whether the gauze is ignited.

[0078] UL-94 flame retardant rating test: The test is conducted in accordance with the UL-94 combustion test standard, the sample thickness is 1.2mm, and the flame is applied to the test sample for 60 seconds each time.

[0079] Limiting Oxygen Index LOI: Tested according to the method of GB / T 2406.2-2009.

[0080] Impact strength: tested at 23°C according to the method of GB / T21189-2007.

[0081] Low temperature resistance: Test the impact strength at -30°C according to the above impact strength test method.

[0082] The results are shown in Table 1 below.

[0083] Table 1 Performance test results

[0084]

[0085] Therefore, as can be known from the data results of above-mentioned Table 1, in polycarbonate, adding hyperbranched flame retardant of the present invention can obviously improve flame retardancy, even adding 1% (relative to the weight of polycarbonate) can also obviously improve needle flame flame retardant effect, adding 3% and above just can reach the needle flame retardant effect of no perforation, no crack, and meet the V-0 level of UL-94 test. Comparative Examples 1-3 can be known, under 1%-5% hyperbranched flame retardant, along with the increase of hyperbranched flame retardant consumption, impact strength and low temperature resistance all obviously improve. Comparative Examples 4-6 can be known, along with the increase of maleic anhydride grafted polymer content in hyperbranched flame retardant, under the same hyperbranched flame retardant consumption, limiting oxygen index descends, but impact strength and low temperature resistance improve, improve hyperbranched flame retardant consumption, can continue to improve flame retardancy, limiting oxygen index, impact strength and low temperature resistance.

[0086] As described above, the basic principles, main features, and advantages of the present invention are shown and described. Those skilled in the art should understand that the present invention is not limited to the above-described embodiments. The above-described embodiments are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. In other words, equivalent changes and modifications made within the scope of the present invention and the contents of the specification should still fall within the scope of the present invention. The scope of protection claimed in the present invention is defined by the appended claims and their equivalents.

Claims

1. A needle flame retardant polycarbonate composition, characterized in that: The raw material components, calculated by weight, include: 100 parts of polycarbonate and 1-15 parts of hyperbranched flame retardant; The hyperbranched flame retardant is obtained by reacting reaction raw materials containing dihydroxyl-terminated polysiloxane and phosphorus oxychloride.

2. The needle flame retardant polycarbonate composition according to claim 1, characterized in that: The molar ratio of the dihydroxy-terminated polysiloxane to the phosphorus oxychloride is 2.8-3.8:

2.

3. The needle flame retardant polycarbonate composition according to claim 1 or 2, characterized in that: The structure of the dihydroxylated polysiloxane is shown in the following formula (1): HOR 1 SiMe2O(SiOMeR 2 ) n SiMe2R 1 OH(1) Among them, R 1 is absent, C2-C6 divalent alkyl, substituted C3-C8 divalent alkyl, R 2 Selected from C1-C4 alkyl, C6-C14 aromatic or C5-C12 cycloalkyl, Me is methyl, and n=3-20.

4. The needle flame retardant polycarbonate composition according to claim 2, characterized in that: When the molar ratio of the dihydroxy-terminated polysiloxane to the phosphorus oxychloride is 3.2-3.8:2, the reaction raw materials further include a maleic anhydride grafted polymer.

5. The needle flame retardant polycarbonate composition according to claim 4, characterized in that: The hyperbranched flame retardant is obtained by reacting the dihydroxyl-terminated polysiloxane with the phosphorus oxychloride and then reacting with the maleic anhydride grafted polymer.

6. The needle flame retardant polycarbonate composition according to claim 4, characterized in that: The molar ratio of the number of moles of maleic anhydride groups in the maleic anhydride grafted polymer to the dihydroxy-terminated polysiloxane is 0.05-0.2:

1.

7. The needle flame retardant polycarbonate composition according to claim 4, characterized in that: The grafting rate of the maleic anhydride grafted polymer is 1-8 wt %.

8. The needle flame retardant polycarbonate composition according to claim 4, characterized in that: The maleic anhydride grafted polymer is selected from one or two of maleic anhydride grafted PE, maleic anhydride grafted PP, maleic anhydride grafted POE, maleic anhydride grafted EVA, maleic anhydride grafted ABS, maleic anhydride grafted SEBS and maleic anhydride grafted SAN, and combinations thereof.

9. The needle flame retardant polycarbonate composition according to claim 1, characterized in that: The raw material components further include one or a combination of two or more of 0.2-1 parts of antioxidant, 0.2-1 parts of anti-ultraviolet agent, 0.1-2 parts of pigment and 0-0.1 parts of anti-dripping agent.

10. A method for preparing the needle flame retardant polycarbonate composition according to any one of claims 1 to 9, characterized in that: The raw material components are mixed evenly, added into a screw extruder for melting, extrusion and molding to obtain the product.

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