PBT / brominated PC alloy, its preparation method and application

Abstract

The application discloses a PBT / brominated PC alloy which comprises the following components in parts by weight: PBT 40-50 parts; brominated PC 30-40 parts; anti-ultraviolet agent 2-10 parts; toughening agent 10-15 parts; anti-dripping agent 0.2-0.5 parts; the viscosity average molecular weight of the brominated PC ranges from 13000 to 80000, and the molar ratio of bisphenol A to tetrabromobisphenol A is (80-40):(20-60); the anti-ultraviolet agent is selected from a copolymer of styrene-N-phenyl maleimide and maleic anhydride. The application has the advantages of good UV resistance and V-0 flame retardance by selecting the brominated PC with specific parameters and the anti-ultraviolet agent.

Description

Technical Field

[0001] This invention relates to the field of polymer materials technology, and in particular to a PBT / brominated PC alloy, its preparation method, and its application. Background Technology

[0002] Polybutyl terephthalate (PBT) is a crystalline thermoplastic with advantages such as rapid crystallization, chemical resistance, and good flowability, but its main drawback is low toughness. Polycarbonate (PC) is a transparent and colorless thermoplastic with high toughness and good dimensional stability, but it has poor flowability and solvent resistance. Blending PBT and PC can overcome the shortcomings of PC, such as poor chemical resistance and poor processability, while compensating for PBT's poor toughness, resulting in good overall performance. However, since both PBT and PC are polyester materials, they undergo severe transesterification reactions under high temperature and high shear processing conditions, affecting the alloy's properties and causing significant yellowing during molding, thus impacting its use.

[0003] Existing technologies address the shortcomings in heat resistance and solvent resistance by adding brominated PC. For example, Chinese patent application CN116355367A discloses a flame-retardant PBT composition. This PBT composition comprises, by weight, 35-45 parts PBT, 20-30 parts brominated PC, 5-10 parts isosorbide copolymerized PC, 2-6 parts antimony-based flame retardant, 0.1-0.4 parts transesterification inhibitor, and 2-5 parts talc. The glass transition temperature of the brominated PC is 160-175℃. However, this flame-retardant PBT composition still requires further optimization regarding its resistance to UV yellowing. Summary of the Invention

[0004] The purpose of this invention is to overcome the above-mentioned technical defects and provide a flame-retardant PBT / brominated PC alloy that is resistant to ultraviolet yellowing.

[0005] This invention is achieved through the following technical solution:

[0006] A PBT / brominated PC alloy, comprising the following components by weight:

[0007] 40-50 copies of PBT;

[0008] 30-40 parts of brominated PC;

[0009] 2-10 parts of UV protectant;

[0010] 10-15 parts toughening agent;

[0011] Anti-dripping agent 0.2-0.5 parts;

[0012] The viscosity-average molecular weight range of the brominated PC is 13,000-80,000, and the molar ratio of bisphenol A to tetrabromobisphenol A is (80-40):(20-60).

[0013] The UV resistant material is selected from a copolymer of styrene-N-phenylmaleimide and maleic anhydride.

[0014] The viscosity-average molecular weight range of the brominated PC of this invention can be 13000, 15000, 20000, 25000, 30000, 35000, 40000, 45000, 50000, 55000, 60000, 65000, 70000, 75000, 80000, etc., and the molar ratio of bisphenol A to tetrabromobisphenol A can be 80:20, 75:25, 70:30, 65:35, 60:40, 55:45, 50:50, 45:55, 40:60, etc.

[0015] In the PBT / brominated PC alloy of the present invention, the content of PBT can be 40 parts, 42 parts, 44 parts, 46 parts, 48 ​​parts, 50 parts, etc.; the content of brominated PC can be 30 parts, 32 parts, 34 parts, 36 parts, 38 parts, 40 parts, etc.; the content of UV stabilizer can be 2 parts, 3 parts, 4 parts, 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, 10 parts, etc.; the content of toughening agent can be 10 parts, 11 parts, 12 parts, 13 parts, 14 parts, 15 parts, etc.; and the content of anti-dripping agent can be 0.2 parts, 0.3 parts, 0.4 parts, 0.5 parts, etc.

[0016] Preferably, the viscosity-average molecular weight of the brominated PC is in the range of 20,000-60,000, and the molar ratio of bisphenol A to tetrabromobisphenol A is (70-50):(30-50).

[0017] More preferably, the viscosity-average molecular weight of the brominated PC is in the range of 25,000-45,000, and the molar ratio of bisphenol A to tetrabromobisphenol A is (65-55):(35-45).

[0018] Brominated polycarbonate can be a commercially available product or obtained via the triphosgene method. The method involves adding bisphenol A, tetrabromobisphenol A, and a solvent to a reactor equipped with a stirrer, condenser, triphosgene, and sodium hydroxide dropping apparatus. Sodium hydroxide solution is then added while stirring until all tetrabromobisphenol A is dissolved. Next, a triphosgene solution in 1,2-dichloroethane is added dropwise. After all additions are complete, the reaction is stirred at 25-30°C for 2-3 hours. After the reaction, the solution is allowed to stand, the organic phase is separated, and repeatedly washed with deionized water. The organic phase is then added to methanol to precipitate the brominated polycarbonate. The molar ratio of bisphenol A to tetrabromobisphenol A in brominated PC is controlled by adjusting the amounts and molar ratio of bisphenol A and tetrabromobisphenol A.

[0019] The solvent can be 1,2-dichloroethane, chloroform, etc. The solvent serves only as a medium and does not participate in the reaction. The amount of solvent has no effect on the final result; it only needs to be sufficient to completely dissolve the substance. There is no specific requirement for the amount of solvent; only economic considerations are necessary.

[0020] The method for determining the viscosity-average molecular weight of brominated PC is as follows: Weigh 4-10 mg of sample and place it in a glass bottle. Add 1 mL of hexafluoroisopropanol according to the 1 mg sample ratio to dissolve the sample and let it stand for about 12 hours. If the sample is not completely dissolved after standing, heat it in a hot plate or steam bath until it is completely dissolved. Then filter the sample solution using a syringe with an organic nylon filter and place it in a glass bottle. Then perform the test using a gel permeation chromatography (GPC) instrument.

[0021] The toughening agent is selected from at least one of the following: ethylene-methyl acrylate-glycidyl methacrylate terpolymer, ethylene-n-butyl acrylate-glycidyl methacrylate terpolymer, organosilicon acrylate toughening agents, and methyl methacrylate-butadiene-styrene copolymer toughening agents.

[0022] Preferably, the toughening agent is selected from silicone acrylate toughening agents.

[0023] The product also includes 0.05-0.5 parts by weight of an ester exchange inhibitor, wherein the ester exchange inhibitor is selected from zinc dihydrogen phosphate.

[0024] The anti-dripping agent is selected from polytetrafluoroethylene.

[0025] By weight, those skilled in the art may choose to add 0-2 parts of additives as needed, wherein the additives are selected from one or more of antioxidants and lubricants. The antioxidants are one or more of hindered phenolic antioxidants, phosphite antioxidants, or thioester antioxidants.

[0026] The preparation method of the PBT / brominated PC alloy of the present invention includes the following steps: mixing the components evenly according to the formula, and granulating by extrusion through a twin-screw extruder to obtain the PBT / brominated PC alloy. The screw temperature is set as follows: Zone 1 temperature 200-220℃, Zone 2 temperature 220-230℃, Zone 3 temperature 230-240℃, Zone 4 temperature 230-240℃, Zone 5 temperature 230-240℃, Zone 6 temperature 230-240℃, Zone 7 temperature 240-250℃, Zone 8 temperature 240-250℃, Zone 9 temperature 230-240℃, and the main extruder speed is 300-400 rpm.

[0027] The application of the PBT / brominated PC alloy of the present invention is used to prepare flame-retardant parts, such as electrical appliance housings and automotive parts.

[0028] The present invention has the following beneficial effects:

[0029] This invention effectively reduces transesterification between PBT and PC by selecting brominated PC with specific parameters, thereby reducing the transesterification reaction between the PBT and polycarbonate molecular chains and improving UV resistance. This is because the brominated PC molecular chain contains a specific amount of tetrabromobisphenol A units, which reduces the molecular chain mobility and thus reduces transesterification. Simultaneously, the addition of UV stabilizers further enhances UV resistance. Therefore, the PBT / brominated PC alloy of this application simultaneously possesses the advantages of V-0 flame retardancy and UV resistance. Detailed Implementation

[0030] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention. These all fall within the scope of protection of the present invention.

[0031] The raw materials used in this invention are sourced from the following sources:

[0032] PBT Resin-A: Grade GX121, intrinsic viscosity 1.0 dl / g, Engineering Plastics Plant, Yizheng Branch, China Petrochemical Corporation Asset Management Co., Ltd.

[0033] PBT resin-B: grade GL236, intrinsic viscosity 1.3 dl / g, engineering plastics plant of Yizheng branch of China Petrochemical Corporation Asset Management Co., Ltd.

[0034] The molar ratio of brominated PC-1:bisphenol A:tetrabromobisphenol A is 80:20, and the viscosity-average molecular weight is 70,000. It was prepared in-house.

[0035] The molar ratio of brominated PC-2:bisphenol A:tetrabromobisphenol A is 70:30, and the viscosity-average molecular weight is 58,500. It was prepared in-house.

[0036] The molar ratio of brominated PC-3:bisphenol A:tetrabromobisphenol A is 65:35, and the viscosity-average molecular weight is 43,000. It was prepared in-house.

[0037] The molar ratio of brominated PC-4:bisphenol A:tetrabromobisphenol A is 55:45, and the viscosity-average molecular weight is 26,000. It was prepared in-house.

[0038] The molar ratio of brominated PC-5:bisphenol A:tetrabromobisphenol A is 50:50, and the viscosity-average molecular weight is 23,000. It was prepared in-house.

[0039] The molar ratio of brominated PC-6:bisphenol A:tetrabromobisphenol A is 40:60, and the viscosity-average molecular weight is 14600. It was prepared in-house.

[0040] The molar ratio of brominated PC-7:bisphenol A:tetrabromobisphenol A is 90:10, and the viscosity-average molecular weight is 75,000. It is self-made.

[0041] The molar ratio of brominated PC-8:bisphenol A:tetrabromobisphenol A is 30:70, and the viscosity-average molecular weight is 10500. It was prepared in-house.

[0042] The preparation method of the above-mentioned brominated PC is as follows: Prepare a reactor equipped with a stirrer, condenser, triphosgene, and sodium hydroxide dropping device. Add bisphenol A, tetrabromobisphenol A, and 1,2-dichloroethane. Add sodium hydroxide solution while stirring, and continue stirring until tetrabromobisphenol A is completely dissolved. Then, add a solution of triphosgene in 1,2-dichloroethane dropwise. After all the addition is complete, stir the reaction at 25-30℃ for 2-3 hours. After the reaction is complete, allow the solution to stand, separate the organic phase, wash the organic phase repeatedly with deionized water, and precipitate the organic phase in methanol to obtain brominated PC. The molar ratio of bisphenol A to tetrabromobisphenol A in brominated PC is controlled by adjusting the amount and molar ratio of bisphenol A and tetrabromobisphenol A.

[0043] Brominated PC-9: Tetrabromobisphenol A carbonate oligomer, brand name BC-58, bromine content 58%, Great Lakes Chemical Company, USA;

[0044] UV stabilizer A: A copolymer of styrene-N-phenylmaleimide and maleic anhydride, brand name DENKA IPMS-NB, manufactured by Nippon Denka Co., Ltd.

[0045] UV stabilizer B: A copolymer of styrene-N-phenylmaleimide and maleic anhydride, brand name HW-330, manufactured by Jiaxing Huawen Chemical Co., Ltd.

[0046] Styrene-N-phenylmaleimide: brand name MS-NIP, Shanghai Better Chemical Co., Ltd.

[0047] Styrene-maleic anhydride copolymer: grade SMA-700, Jiaxing Huawen Chemical Co., Ltd.

[0048] Toughening agent A: Ethylene-methyl acrylate-glycidyl methacrylate terpolymer, brand name LOTADERAX8900, GMA content 8%, Arkema, France.

[0049] Toughening agent B: Ethylene-n-butyl acrylate-glycidyl methacrylate terpolymer, brand name Elvaloy® PTW, GMA content 5%, DuPont, USA.

[0050] Toughening agent C: Organosilicon acrylate toughening agent, brand name METABLEN S-2001, Mitsubishi Corporation;

[0051] Toughening agent D: Methyl methacrylate-butadiene-styrene copolymer toughening agent, brand name EM500, LG Corporation of South Korea;

[0052] Zinc dihydrogen phosphate: grade BUDIT T21, manufactured by Budenheim GmbH, Germany;

[0053] Polytetrafluoroethylene (PTFE): Anti-dripping agent, commercially available;

[0054] Antioxidant: A 1:1 blend of RIANOX1010 and RIANOX 168, Tianjin Anlong New Materials Co., Ltd.

[0055] Preparation method of PBT / brominated PC alloy in the examples and comparative examples: The components were mixed evenly according to the formula, and then extruded and granulated using a twin-screw extruder to obtain the PBT / brominated PC alloy. The screw temperatures were set as follows: Zone 1: 200-220℃; Zone 2: 220-230℃; Zone 3: 230-240℃; Zone 4: 230-240℃; Zone 5: 230-240℃; Zone 6: 230-240℃; Zone 7: 240-250℃; Zone 8: 240-250℃; Zone 9: 230-240℃; and the main extruder speed was 300-400 rpm.

[0056] Test methods:

[0057] (1) Flame retardancy: According to UL94 standard, 0.8mm specimens were injection molded and flame retardancy was determined using a combustion chamber.

[0058] (2) Resistance to UV yellowing: The sample was injection molded into a square plate according to ASTM G155-2013 standard, with a blackboard temperature of 63±2.5℃ and a light intensity of 0.35W / m. 2 @340nm, 102min illumination, 18min illumination + spray, irradiation time 1200h. The testing equipment was manufactured by ATLAS (USA), model CI4000. The color difference change value was calculated using the following formula:

[0059]

[0060] L1,a1,b1: Test values ​​before xenon lamp aging;

[0061] L2,a2,b2: Test values ​​after xenon lamp aging;

[0062] The color difference testing equipment was manufactured by X-Rite, USA, model Color-Eye 7000A.

[0063] Table 1: Component content and test results of PBT / brominated PC alloys in Examples 1-7

[0064] Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 PBT Resin-A 40 45 40 40 40 40 PBT resin-B 50 Brominated PC designation 1 1 1 2 3 4 5 Brominated PC content 40 35 40 40 40 40 40 UV protectant A 5 10 2 5 5 5 5 Toughening agent A 13 15 10 13 13 13 13 Zinc dihydrogen phosphate 0.2 0.5 0.1 0.2 0.2 0.2 0.2 polytetrafluoroethylene 0.3 0.4 0.5 0.3 0.3 0.3 0.3 antioxidants 0.3 0.3 0.3 0.3 0.3 0.3 Flame retardancy V-0 V-0 V-0 V-0 V-0 V-0 V-0 UV resistance to yellowing 2.59 1.92 3.63 2.45 2.37 2.40 2.50

[0065] As can be seen from Examples 1 / 4 / 5 / 6 / 7 / 8, brominated PC with preferred repeating units exhibits better resistance to UV yellowing.

[0066] Table 2: Component content and test results of PBT / brominated PC alloys in Examples 8-12

[0067] Example 8 Example 9 Example 10 Example 11 Example 12 PBT Resin-A 40 40 40 40 40 PC-1 bromide 40 40 40 40 brominated PC-6 40 UV protectant A 5 5 5 5 UV protectant B 5 Toughening agent A 13 13 Toughening agent B 13 Toughening agent C 13 Toughening agent D 13 Zinc dihydrogen phosphate 0.2 0.2 0.2 0.2 0.2 polytetrafluoroethylene 0.3 0.3 0.3 0.3 0.3 antioxidants 0.3 0.3 0.3 0.3 0.3 Flame retardancy V-0 V-0 V-0 V-0 V-0 UV resistance to yellowing 2.69 2.49 2.57 2.46 2.63

[0068] As can be seen from Examples 1 / 10-12, the toughening agent is preferably an organosilicon acrylate toughening agent.

[0069] As can be seen from the above embodiments, the PBT / brominated PC alloy of the present invention has V-0 flame retardancy and UV yellowing resistance ΔE less than 3.8.

[0070] Table 3: Component content and test results of the comparative PBT / brominated PC alloy

[0071] Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Comparative Example 6 Comparative Example 7 PBT Resin-A 40 40 40 40 40 50 40 Brominated PC designation 7 8 9 1 1 1 1 Brominated PC content 40 40 40 40 40 20 50 UV protectant A 5 5 5 0 1 5 5 Toughening agent A 13 13 13 13 13 13 13 Zinc dihydrogen phosphate 0.2 0.2 0.2 0.2 0.2 0.2 0.2 polytetrafluoroethylene 0.3 0.3 0.3 0.3 0.3 0.3 0.3 antioxidants 0.3 0.3 0.3 0.3 0.3 0.3 0.3 Flame retardancy V-0 V-0 V-0 V-0 V-0 V-2 V-0 UV resistance to yellowing 2.94 3.12 5.65 4.37 4.36 2.11 4.68

[0072] As can be seen from Comparative Example 1 / 2, if the molar content of the monomer of brominated PC is not within the range of the present invention, the resistance to UV yellowing is poor.

[0073] As can be seen from Comparative Example 3, the low molecular weight brominated PC commonly used in this field is prone to transesterification with PBT, resulting in a severe decrease in yellowing resistance.

[0074] As shown in Comparative Example 4, the resistance to UV yellowing is poor when it does not contain anti-yellowing agents.

[0075] As shown in Comparative Example 5, when the content of anti-yellowing agent is too low, the resistance to ultraviolet yellowing is insufficient.

[0076] As shown in Comparative Example 6, if the content of brominated PC is too low, the flame retardancy of V0 cannot be achieved.

[0077] As shown in Comparative Example 7, if the content of brominated PC is too low, the resistance to UV yellowing will be severely reduced.

Claims

1. A PBT / brominated PC alloy, characterized in that, By weight, it includes the following components: 40-50 copies of PBT; 30-40 parts of brominated PC; 2-10 parts of UV protectant; 10-15 parts toughening agent; Anti-dripping agent 0.2-0.5 parts; The viscosity-average molecular weight range of the brominated PC is 13,000-80,000, and the molar ratio of bisphenol A to tetrabromobisphenol A is (80-40):(20-60). The UV stabilizer is a copolymer of styrene-N-phenylmaleimide and maleic anhydride.

2. The PBT / brominated PC alloy according to claim 1, characterized in that, The viscosity-average molecular weight range of the brominated PC is 20,000-60,000, and the molar ratio of bisphenol A to tetrabromobisphenol A is (70-50):(30-50).

3. The PBT / brominated PC alloy according to claim 2, characterized in that, The viscosity-average molecular weight range of the brominated PC is 25,000-45,000, and the molar ratio of bisphenol A to tetrabromobisphenol A is (65-55):(35-45).

4. The PBT / brominated PC alloy according to claim 1, characterized in that, The toughening agent is selected from at least one of the following: ethylene-methyl acrylate-glycidyl methacrylate terpolymer, ethylene-n-butyl acrylate-glycidyl methacrylate terpolymer, organosilicon acrylate toughening agents, and methyl methacrylate-butadiene-styrene copolymer toughening agents.

5. The PBT / brominated PC alloy according to claim 4, characterized in that, The toughening agent is a silicone acrylate toughening agent.

6. The PBT / brominated PC alloy according to claim 1, characterized in that, The product also includes 0.05-0.5 parts by weight of an ester exchange inhibitor, wherein the ester exchange inhibitor is selected from zinc dihydrogen phosphate.

7. The PBT / brominated PC alloy according to claim 1, characterized in that, The anti-dripping agent is polytetrafluoroethylene.

8. The PBT / brominated PC alloy according to claim 1, characterized in that, The product also includes 0-2 parts by weight of additives, which are selected from one or more antioxidants and lubricants.

9. The method for preparing the PBT / brominated PC alloy according to any one of claims 1-8, characterized in that, The process includes the following steps: mixing the components evenly according to the formula, and granulating them by extrusion through a twin-screw extruder to obtain a PBT / brominated PC alloy.

10. The application of the PBT / brominated PC alloy according to any one of claims 1-8, characterized in that, Used to manufacture flame-retardant components, such as appliance housings or automotive parts.