A flame resistant polycarbonate composition resistant to needle flame and a method of making the same

Abstract

The application 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 contains, in terms of weight parts, 100 parts of polycarbonate and 1-15 parts of a hyperbranched flame retardant; the hyperbranched flame retardant is obtained by reacting raw materials containing double-end hydroxyl polysiloxane and phosphorus oxychloride. The application adds the hyperbranched flame retardant to the polycarbonate, combines the characteristics of polysiloxane and organic phosphate, has good flame-retardant performance, and achieves needle flame resistance, flame retardation and UL-94 vertical combustion V-0 grade.

Description

Technical Field

[0001] This invention belongs to the technical field of flame-retardant polycarbonate materials, and relates to a needle flame resistant flame-retardant polycarbonate composition and its preparation method. Background Technology

[0002] Polycarbonate, or PC for short, possesses excellent properties such as ease of processing, high transparency, and high mechanical strength, leading to its wide application in various fields. However, its poor flame retardancy affects its safety during application. Therefore, flame retardants are generally added to polycarbonate to improve its flame retardancy. Commonly used flame retardants for polycarbonate include halogenated flame retardants, phosphate ester flame retardants, inorganic flame retardants, and organosilicon flame retardants. To further improve the flame retardant properties, two or more flame retardants are usually combined using physical and chemical composite methods, or hyperbranched flame retardants with hyperbranched structures may be employed. Chinese patent CN114479407A discloses a thin-walled flame-retardant polycarbonate material, which incorporates a compounded flame retardant, a phosphorus-based flame retardant, and a charring agent into polycarbonate. The compounded flame retardant consists of potassium diphenyl sulfonate, potassium perfluorobutyl sulfonate, and octaphenyl cage-like silsesquioxane, while the charring agent is a hyperbranched macromolecular flame-retardant charring agent. The above method requires the combined use of compound flame retardants and hyperbranched flame retardants.

[0003] Among the flame retardant performance testing methods, the needle flame test and the UL-94 vertical burning test (e.g., achieving a V-0 rating) have relatively high requirements. However, these two flame retardant tests have different methods and requirements, and the test results cannot be equated, and may even be contradictory. To achieve vertical flame retardancy, plastic products generally have anti-dripping agents (such as PTFE) added. However, excessive amounts of anti-dripping agents can cause the molten plastic to shrink during combustion, leading to burn-through and failing to meet the needle flame retardancy requirements. Currently, there are few reports of PC, after flame retardancy enhancement, simultaneously meeting both the needle flame retardancy test requirements and the UL-94 vertical burning test V-0 rating. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention provides a flame-retardant polycarbonate composition resistant to needle flames and its preparation method.

[0005] The technical solution of the present invention is as follows:

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

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

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

[0009] Preferably, the structure of the double-hydroxyl-terminated polysiloxane is shown in formula (1).

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

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

[0012] More preferably, when the molar ratio of the dihydroxyl-terminated polysiloxane to the phosphorus oxychloride is 3.2-3.8:2, the reactants further include maleic anhydride grafted polymer.

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

[0014] More preferably, the molar ratio of maleic anhydride groups in the maleic anhydride graft polymer to the molar ratio of the dihydroxyl-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] More 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, as well as combinations thereof.

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

[0018] A method for preparing a needle-flame resistant flame-retardant polycarbonate composition according to any of the above embodiments involves mixing the raw material components evenly, adding them to a screw extruder for melt extrusion and molding, thereby obtaining the composition.

[0019] The beneficial effects of this invention are:

[0020] (1) The hyperbranched flame retardant of the present invention combines the flame retardant properties of organosilicon and organophosphate, and adopts a hyperbranched structure to synergistically exert the flame retardant effect of the two flame retardants, thus having better flame retardant performance, and enabling PC to simultaneously meet the requirements of needle flame retardancy and the V-0 rating of UL-94 vertical burning.

[0021] (2) When maleic anhydride graft copolymer is further introduced into hyperbranched flame retardant, the compatibility between hyperbranched flame retardant and 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 Implementation

[0023] The technical solution of the present invention will be further explained and described below through specific embodiments.

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

[0025] The aforementioned hyperbranched flame retardant is obtained by reacting reactants containing dihydroxyl-terminated polysiloxane and phosphorus oxychloride.

[0026] Hyperbranched flame retardants possess a unique structure, exhibiting good flame retardant properties against polycarbonate even at relatively low dosages. This invention utilizes a hyperbranched flame retardant that combines the flame retardant properties of polysiloxanes and organophosphates, and features a hyperbranched structure, resulting in superior flame retardant effects compared to either polysiloxanes or organophosphates alone. The P-Cl group in phosphorus oxychloride exhibits high reactivity, reacting with the terminal hydroxyl groups of dihydroxyl-terminated polysiloxanes to obtain a hyperbranched structure. The phosphorus oxychloride structure contains three P-Cl groups (A3), while the dihydroxyl-terminated polysiloxane structure contains two OH groups (B2), resulting in an "A3+B2" type hyperbranched flame retardant.

[0027] For example, the weight parts of the hyperbranched flame retardant in the polycarbonate composition can be any value among 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 parts can be 3-15 parts.

[0028] In some embodiments, the molar ratio of hydroxyl-terminated polysiloxane to phosphorus oxychloride is 2.8-3.8:2. Within this range, a hyperbranched flame retardant with a hyperbranched structure can be obtained. For example, the molar ratio of hydroxyl-terminated polysiloxane to phosphorus oxychloride can be any value from 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 limitation. Furthermore, a molar ratio of hydroxyl-terminated polysiloxane to phosphorus oxychloride can be 3-3.8:2, which allows for a more complete reaction of the P-Cl groups in phosphorus oxychloride, preventing Cl residues in the hyperbranched flame retardant from causing excessive halogen content or unstable product quality in subsequent products.

[0029] In some embodiments, the structure of the hydroxyl-terminated polysiloxane is shown in formula (1).

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

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

[0032] In this invention, there are no particular limitations on the hydroxyl-terminated polysiloxane. Considering the reactivity of the terminal hydroxyl groups, the hydroxyl-terminated polysiloxane can be a hydroxyl-terminated alkyl polysiloxane, such as hydroxypropyl polydimethylsiloxane (R in formula (1) above). 1 For -(CH2)3, R 2 (R is methyl), dihydroxypropyl polymethylphenylsiloxane (in formula (1) above) 1 For -(CH2)3, R 2 It is a combination of methyl and phenyl, with the phenyl content being 5-20 mol%), and bihydroxybutyl polydimethylsiloxane (R in formula (1) above) 1 It is -(CH2)4, R 2(e.g., methyl). The degree of polymerization n should not be too high, as this will reduce the activity of the terminal hydroxyl groups and result in an excessively low content of organophosphate esters in the hyperbranched flame retardant. For example, n can be any value from 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 are no particular restrictions on the source of the bihydroxyl-terminated polysiloxane; it can be obtained directly from the market or prepared according to existing technologies, as is known to those skilled in the art. For example, 1,3-dihydroxypropyl-1,1,3,3-tetramethyldisiloxane can be used as the end-capping agent, and siloxane cyclic compounds (e.g., octamethylcyclotetrasiloxane D4, tetramethyltetraphenylcyclotetrasiloxane D4) can be used. Ph The above-mentioned preparation method for dihydroxyl-terminated polysiloxanes involves the ring-opening polymerization of dialkoxysilanes (e.g., methylphenyldimethoxysilane) and / or dialkoxysilanes (e.g., methylphenyldimethoxysilane) at a certain temperature (e.g., 110-120℃) using tetramethylammonium siloxane (commonly known as ammonium styrene or alkali styrene) as a catalyst. After the reaction, the temperature is raised to a higher temperature (e.g., 135-140℃) to decompose and destroy the catalyst, and then the low-boiling substances are removed under reduced pressure to obtain the final product. The average degree n can be determined based on the molar ratio of the end-capping agent to the siloxane ring. Alternatively, the preparation method of the above-mentioned dihydroxyl-terminated polysiloxanes can also use strong acids (e.g., concentrated sulfuric acid, acidic clay, strong acidic cation exchange resin, trifluoromethylbenzenesulfonic acid, etc.) as catalysts, and the ring-opening polymerization reaction is carried out at a certain temperature (e.g., 50-90℃). After the reaction, the acid catalyst is removed (e.g., by filtration or neutralization), and then the temperature is raised and the low-boiling substances are removed under reduced pressure to obtain the final product.

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

[0034] When the molar ratio of the aforementioned hydroxyl-terminated polysiloxane to phosphorus oxychloride is 3.2-3.8:2, in some embodiments, the hyperbranched flame retardant is obtained by reacting the hydroxyl-terminated polysiloxane and phosphorus oxychloride 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 the hydroxyl and carboxyl groups in polycarbonate, allowing the hyperbranched flame retardant to bond with polycarbonate through chemical bonds. As mentioned above, hyperbranched flame retardants contain a certain amount of hydroxyl groups at their end groups. After further reaction with maleic anhydride graft polymers, the maleic anhydride graft polymers are introduced into the structure of the hyperbranched flame retardant. Since maleic anhydride groups can also react with polycarbonate, the hyperbranched flame retardant can be chemically bonded to the polycarbonate. While maintaining good flame retardant properties, it can also optimize other properties of polycarbonate. For example, the polysiloxane structure, which provides good flexibility and low-temperature resistance, can improve the impact resistance and low-temperature resistance of the polycarbonate composition. Compared to physically mixing hyperbranched flame retardants into polycarbonate, grafting hyperbranched flame retardants into polycarbonate through chemical methods results in more outstanding performance. Although the addition of maleic anhydride graft polymers to hyperbranched flame retardants reduces the effective content of polysiloxanes and organophosphates in the hyperbranched flame retardants, resulting in a certain degree of decrease in flame retardant performance when the same weight ratio of hyperbranched flame retardants is added, the flame retardant performance is still good. Moreover, it can improve other properties of polycarbonate, and the flame retardant performance can be compensated for and improved by adding more hyperbranched flame retardants.

[0035] When the molar ratio of dihydroxyl-terminated polysiloxane to phosphorus oxychloride is 3.2-3.8:2, in some embodiments, the molar ratio of maleic anhydride groups in the maleic anhydride graft polymer to that of dihydroxyl-terminated polysiloxane is 0.05-0.2:1. If the molar ratio of maleic anhydride groups in the maleic anhydride graft polymer is too low, most or all of the maleic anhydride groups will be reacted, weakening or eliminating the effect of the maleic anhydride graft polymer; if the molar ratio of maleic anhydride groups in the maleic anhydride graft polymer is too high, it is equivalent to introducing too much maleic anhydride graft polymer, which will lead to a decrease in the flame retardant properties of the polycarbonate composition. For example, the molar ratio of maleic anhydride groups to dihydroxyl-terminated polysiloxane in a maleic anhydride-grafted polymer can be any of the following values: 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 1-8 wt%. The grafting rate of the maleic anhydride-grafted polymer refers to the ratio of the weight of maleic anhydride monomer successfully grafted onto the polymer backbone after the grafting reaction to the initial polymer weight. For example, the grafting rate can be any value among 1 wt%, 1.5 wt%, 2 wt%, 2.5 wt%, 3 wt%, 3.5 wt%, 4 wt%, 4.5 wt%, 5 wt%, 5.5 wt%, 6 wt%, 6.5 wt%, 7 wt%, 7.5 wt%, 8 wt%, etc., without particular limitation.

[0037] In some embodiments, the maleic anhydride-grafted polymer is selected from one or a combination of two or more 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). These maleic anhydride-grafted polymers are readily available from the market, such as those from companies like KOAS Chemical Co., Ltd. and Nanjing Feiteng New Material Technology Co., Ltd.

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

[0039] On the other hand, the present invention also proposes a method for preparing the needle-flame resistant flame-retardant polycarbonate composition described in any of the above embodiments, wherein the raw material components are mixed evenly, added to a screw extruder for melt extrusion and molding, and thus obtained. Specifically, in one method, the raw material components are pre-dried at 90-120°C until the water content does not exceed 0.1 wt%. The screw extruder used is a twin-screw extruder with a melt temperature of 230-280°C and an extruder head temperature of 270°C.

[0040] The polycarbonate composition obtained by this invention has good flame retardant properties and impact resistance, and can be used in many fields such as automotive parts, electronic products, medical devices, sports equipment, and aerospace.

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

[0042] Preparation Examples 1-4: Preparation of Hyperbranched Flame Retardants

[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 solution of dihydroxypropyl polydimethylsiloxane (0.152 mol of dihydroxypropyl polydimethylsiloxane (n = 5.5 in formula (1) above) was added dropwise to 300 ml of anhydrous tetrahydrofuran. After the addition was complete, the mixture was stirred in an ice-water bath for 6 h, then stirred at room temperature for 2 h, and then heated to 50 °C for 5 h. After cooling to room temperature, the mixture was filtered, and the filtrate was concentrated to about 200 ml and 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, denoted 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 dihydroxypropyl polymethylphenylsiloxane (n = 12.7 in the above formula (1) and the molar ratio of phenyl is 15%) was added dropwise (0.16 mol of dihydroxypropyl polydimethylsiloxane dissolved in 300 ml of anhydrous tetrahydrofuran). After the addition was complete, the mixture was stirred in an ice-water bath for 6 h, then stirred at room temperature for 2 h, and then heated to 50 °C for 5 h. After cooling to room temperature, the mixture was filtered, and the filtrate was concentrated to 300 ml and added to 3000 ml of methanol. The mixture was separated and the product was collected. The product was dried in an oven at 50 °C overnight to obtain a hyperbranched flame retardant, denoted as R-2.

[0047] Preparation Example 3

[0048] POE-g-MAH (grafting rate 2.2 wt%) and hyperbranched flame retardant R-2 obtained in Preparation Example 2 (molar ratio of maleic anhydride group and dihydroxypropyl polydimethylsiloxane is 0.05:1) were dried to a water content of no more than 0.1 wt%, mixed evenly, and added to a twin-screw extruder. The mixture was melt-extruded and granulated 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 dihydroxybutyl polydimethylsiloxane (n = 18.1 in formula (1) above) was added dropwise (0.19 mol of dihydroxybutyl polydimethylsiloxane dissolved in 500 ml of anhydrous tetrahydrofuran). After the addition was complete, the mixture was stirred in an ice-water bath for 6 h, then stirred at room temperature for 2 h, and then heated to 50 °C for 3 h. After cooling to room temperature, the mixture was filtered, and the filtrate was concentrated to about 400 ml and added to 5000 ml of methanol. The mixture was separated and the product was collected. The product was dried in an oven at 50 °C overnight to obtain the hyperbranched intermediate.

[0051] The above hyperbranched intermediate and ABS-g-MAH (grafting rate 4.5wt%) (molar ratio of maleic anhydride group and dihydroxypropyl polydimethylsiloxane is 0.2:1) were dried to a water content of no more than 0.1wt%, mixed evenly, and added to a twin-screw extruder. The mixture was then melt-extruded and granulated at 160-190℃ to obtain hyperbranched flame retardant R-4.

[0052] Example 1

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

[0054] Polycarbonate and hyperbranched flame retardant R-1 were dried at 110°C until the water content was less than 0.1 wt%. After being mixed evenly, they were added to a twin-screw extruder and melted at 230-280°C. After cooling and pelletizing, a polycarbonate composition was obtained.

[0055] Example 2

[0056] The difference between this embodiment and Embodiment 1 is that in Embodiment 1, the hyperbranched flame retardant R-1 was changed from 20g to 60g. The remaining steps remain unchanged.

[0057] Example 3

[0058] The difference between this embodiment and Embodiment 1 is that in Embodiment 1, the hyperbranched flame retardant R-1 was changed from 20g to 100g. 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 was replaced with 100g DOPO. The remaining steps remained unchanged.

[0061] Example 4

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

[0063] Prepared 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, hyperbranched flame retardant R-2 is replaced with an equal weight of 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 was replaced with an equal weight of DOPO. The remaining steps remained unchanged.

[0068] Example 6

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

[0070] Example 7

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

[0072] Example 8

[0073] The polycarbonate composition consists of 2000g of polycarbonate, 160g of hyperbranched flame retardant R-3 from Preparation Example 3, 6g of UV stabilizer UV327, 8g of antioxidant 168, and 0.5g of anti-dripping agent polytetrafluoroethylene micropowder.

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

[0075] Example 9

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

[0077] Needle flame retardancy test: The test is conducted according to the method of GB / T 5169.5-2020. The thickness of the color plate made of PC is 1mm. After 60s, observe the burning of the polycarbonate composition, whether the color plate is perforated or cracked, and whether the gauze is ignited.

[0078] UL-94 Flame Retardant Rating Test: The test is conducted according to the UL-94 flammability test standard. The sample thickness is 1.2 mm, and the flame is applied to the test sample for 60 seconds each time.

[0079] Limiting oxygen index (LOI): Tested according to the method in GB / T 2406.2-2009.

[0080] Impact strength: Tested at 23℃ according to the method of GB / T21189-2007.

[0081] Low temperature resistance: The impact strength at -30℃ was tested according to the above-mentioned impact strength test method.

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

[0083] Table 1 Performance Test Results

[0084]

[0085] Therefore, as shown in Table 1 above, adding the hyperbranched flame retardant of this invention to polycarbonate can significantly improve its flame retardant performance. Even adding 1% (relative to the weight of polycarbonate) can significantly improve the needle flame retardant effect, and adding 3% or more can achieve a needle flame retardant effect without perforation or cracking, while meeting the V-0 level of the UL-94 test. Comparing Examples 1-3, it can be seen that with 1%-5% hyperbranched flame retardant, the impact strength and low-temperature resistance are significantly improved with the increase of the amount of hyperbranched flame retardant. Comparing Examples 4-6, it can be seen that with the increase of the maleic anhydride graft polymer content in the hyperbranched flame retardant, the limiting oxygen index decreases at the same amount of hyperbranched flame retardant, but the impact strength and low-temperature resistance increase. Increasing the amount of hyperbranched flame retardant can further improve the flame retardant performance, limiting oxygen index, impact strength, and low-temperature resistance.

[0086] As described above, the basic principles, main features, and advantages of the present invention have been shown and described. Those skilled in the art should understand that the present invention is not limited to the above embodiments, which are merely preferred embodiments and should not be construed as limiting the scope of the invention. All equivalent changes and modifications made in accordance with the scope of the patent and the description should still fall within the scope of the present invention. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A flame retardant polycarbonate composition resistant to needle flame, characterized in that, The raw material components include, by weight parts, 100 parts of polycarbonate and 1-15 parts of hyperbranched flame retardant; The hyperbranched flame retardant is obtained by reacting reaction raw materials including double-end hydroxyl polysiloxane, phosphorus oxychloride and maleic anhydride grafted polymer; The molar ratio of the double-end hydroxyl polysiloxane to the phosphorus oxychloride is 3.2-3.8:2; The hyperbranched flame retardant is obtained by reacting the double-end hydroxyl polysiloxane and the phosphorus oxychloride and then reacting with the maleic anhydride grafted polymer.

2. The needle flame resistant flame-retardant polycarbonate composition of claim 1, wherein, The double-end hydroxyl polysiloxane has the following structure shown in formula (1), HOR 1 SiMe2O(SiOMeR 2 ) n SiMe2R 1 OH (1) wherein R 1 is absent, C2-C6divalent alkyl or substituted C3-C8divalent alkyl, R 2 is selected from C1-C4alkyl, C6-C14aromatic or C5-C12cycloalkyl, Me is methyl, and n = 3-20.

3. The needle flame resistant flame-retardant polycarbonate composition of claim 1, wherein, The molar ratio of the number of maleic anhydride groups in the maleic anhydride grafted polymer to the double-end hydroxyl polysiloxane is 0.05-0.2:

1.

4. The needle flame resistant flame-retardant polycarbonate composition of claim 1, wherein, The grafting rate of the maleic anhydride grafted polymer is 1-8 wt%.

5. The needle flame resistant flame-retardant polycarbonate composition of claim 1, wherein, 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.

6. The needle flame resistant flame-retardant polycarbonate composition of claim 1, wherein, The raw material components further include one or two or more of 0.2-1 parts of antioxidant, 0.2-1 parts of ultraviolet light resistant agent, 0.1-2 parts of pigment and 0-0.1 parts of anti-dripping agent and combinations thereof.

7. A process for the preparation of the flame resistant polycarbonate composition according to any one of claims 1 to 6, characterized in that, The raw material components are mixed uniformly and added to a screw extruder for melt extrusion and molding, thereby obtaining the product.

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