Flame-retardant pbt / brominated polycarbonate compositions, process for their preparation and use

Abstract

The application discloses a kind of flame-retardant PBT / brominated polycarbonate compositions, by weight parts, including the following components: PBT 40-60 parts;Brominated polycarbonate 30-50 parts;Anti-dripping agent 0.2-0.5 parts;Glycidyl methacrylate grafting toughening agent 10-15 parts;The viscosity average molecular weight range of the brominated PC is 13000-30000, and the molar ratio of bisphenol A: tetra-bromobisphenol A is (55-40): (45-60).The application can realize V-0 flame retardancy while realizing high low-temperature toughness (notched impact performance of-30 DEG C test), the advantage of low shrinkage after baking by selecting brominated polycarbonate with specific parameters, glycidyl methacrylate grafting toughening agent.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of high polymer materials, in particular to a flame-retardant PBT / brominated polycarbonate composition, a preparation method and application thereof. BACKGROUND

[0002] Polybutylene terephthalate (PBT) is a crystalline thermoplastic plastic with the advantages of fast crystallization speed, good chemical resistance and flowability, but its main disadvantage is low toughness. Polycarbonate (PC) is a transparent and colorless thermoplastic plastic, and its biggest advantage is high toughness and good dimensional stability, but its flowability and solvent resistance are poor. PBT and PC can overcome the poor chemical resistance and poor molding process of PC, and make up for the low toughness of PBT, so that good comprehensive performance can be obtained. However, PBT and PC belong to polyester materials, and ester exchange reaction will occur under high temperature and high shear processing conditions, thereby affecting the performance of the alloy.

[0003] The prior art adds brominated PC to solve the defects of poor heat resistance and poor solvent resistance. For example, Chinese patent application CN116355367A discloses a flame-retardant PBT composition. The PBT composition comprises, by weight fraction: PBT 35-45 parts, brominated PC 20-30 parts, isosorbide copolymer PC 5-10 parts, antimony flame retardant 2-6 parts, ester exchange inhibitor 0.1-0.4 parts, and talc 2-5 parts. The glass transition temperature of the brominated PC is 160-175℃. However, the notched impact performance of the flame-retardant PBT composition at -30℃ still needs to be further optimized. SUMMARY

[0004] The present application aims to overcome the above technical defects and provide a flame-retardant PBT / polycarbonate composition with V-0 flame retardancy, good notched impact performance at -30℃ and low shrinkage.

[0005] The present application is achieved by the following technical solutions:

[0006] A flame-retardant PBT / brominated polycarbonate composition, comprising the following components by weight fraction:

[0007] PBT 40-60 parts;

[0008] Brominated polycarbonate 30-50 parts;

[0009] Anti-dripping agent 0.2-0.5 parts;

[0010] Glycidyl methacrylate grafted toughening agent 10-15 parts;

[0011] The viscosity average molecular weight of the brominated polycarbonate is in the range of 13000-30000, and the molar ratio of bisphenol A: tetrabromobisphenol A is (55-40):(45-60).

[0012] The viscosity average molecular weight of the brominated polycarbonate can be 13000, 14000, 15000, 16000, 17000, 18000, 19000, 20000, 21000, 22000, 23000, 24000, 25000, 26000, 27000, 28000, 29000, 30000, etc., and the molar ratio of bisphenol A: tetrabromobisphenol A can be 55:45, 54:46, 53:47, 52:48, 51:49, 50:50, 49:51, 48:52, 47:53, 46:54, 45:55, etc.

[0013] Preferably, the viscosity average molecular weight of the brominated PC is in the range of 17000-24000, and the molar ratio of bisphenol A: tetrabromobisphenol A is (50-45):(50-55).

[0014] In the flame-retardant PBT / brominated polycarbonate composition of the present application, the content of PBT is not less than 35wt% of the total weight. The content of PBT can be 40 parts, 42 parts, 44 parts, 46 parts, 48 parts, 50 parts, 52 parts, 54 parts, 56 parts, 58 parts, 60 parts, etc., the content of brominated polycarbonate can be 30 parts, 32 parts, 34 parts, 36 parts, 38 parts, 40 parts, 42 parts, 44 parts, 46 parts, 48 parts, 50 parts, etc., and the content of anti-dripping agent can be 0.2 parts, 0.3 parts, 0.4 parts, 0.5 parts, etc. The content of glycidyl methacrylate grafted toughening agent can be 10 parts, 11 parts, 12 parts, 13 parts, 14 parts, 15 parts, etc.

[0015] The brominated polycarbonate can be a commercially available product or obtained by a triphosgene method. The method specifically comprises: adding bisphenol A, tetrabromobisphenol A, and a solvent into a reactor provided with a stirrer, a condenser, a triphosgene and sodium hydroxide dropping device, adding a sodium hydroxide solution under stirring, and stirring until the tetrabromobisphenol A is completely dissolved after the addition. Then, a 1,2-dichloroethane solution of triphosgene is added dropwise. After the complete addition, the solution is stirred at 25-30℃ for 2-3 hours. After the reaction is completed, the solution is left to stand, the organic phase is separated, the organic phase is repeatedly washed with deionized water, and the organic phase is added into methanol for precipitation to obtain the brominated polycarbonate. The molar ratio of bisphenol A:tetrabromobisphenol A in the brominated PC is controlled by controlling the amount and molar ratio of bisphenol A and tetrabromobisphenol A.

[0016] The solvent can be 1,2-dichloroethane, chloroform, etc. The solvent is only used as a medium and does not participate in the reaction. The amount of solvent has no effect on the final result. It can be completely dissolved. The amount of solvent is not specified. Only economic efficiency needs to be considered.

[0017] The test method of the viscosity average molecular weight of the brominated polycarbonate is as follows: 4-10 mg of the sample is placed in a glass bottle, 1 mL of hexafluoroisopropanol is added for every 1 mg of the sample, and the sample is dissolved and left to stand for about 12 h. If the sample is not completely dissolved after standing, it is heated on a heating plate or in a steam bath until it is completely dissolved. Then the sample solution is filtered into a glass bottle using a needle tube and an organic nylon filter head. Then it is tested in a gel permeation chromatograph (GPC).

[0018] The glycidyl methacrylate grafted toughener is at least one selected from a glycidyl methacrylate grafted ethylene-methyl acrylate copolymer toughener and a glycidyl methacrylate grafted ethylene-butyl acrylate copolymer toughener.

[0019] In the glycidyl methacrylate grafted toughener, the grafting rate of glycidyl methacrylate is 0.4-2.1 wt%, preferably 0.8-1.3 wt%.

[0020] The glycidyl methacrylate grafted toughener can be obtained commercially or by self-preparation. The self-preparation method is as follows: glycidyl methacrylate, an initiator, and a toughener before grafting (an ethylene-methyl acrylate copolymer toughener or an ethylene-butyl acrylate copolymer toughener) are uniformly mixed, and then extruded and granulated by a twin-screw extruder (the screw temperature is 150-180°C, and the length-diameter ratio is greater than or equal to 40:1) to obtain the glycidyl methacrylate grafted toughener. The initiator is at least one selected from dicumyl peroxide, di-tert-butyl peroxide, tert-butyl hydroperoxide, and cumene hydroperoxide, and the addition amount is 0.2-0.8 wt% of the addition amount of the toughener before grafting.

[0021] The test method of the GMA grafting rate of the glycidyl methacrylate grafted toughener is acid-base titration. The specific operation method can be as follows: the grafting product is dissolved by heating and refluxing in xylene, a certain amount of 0.05 mol / L potassium hydroxide-ethanol solution is added after cooling, and then heated and refluxed for 8 h. With 0.1% phenolphthalein solution as an indicator, 0.05 mol / L HCl-isopropyl alcohol solution is added dropwise until the end point. The grafting rate G is calculated by the following formula:

[0022] G=(N1×Vl—N2×V2)×M÷w÷10

[0023] In the formula, N1 is the equivalent concentration of KOH-ethanol solution, N;

[0024] V1: volume of KOH-ethanol solution, ml;

[0025] N2: equivalent concentration of HCl-isopropanol solution, N;

[0026] V2: volume of HCl-isopropanol solution, ml;

[0027] M: equivalent mass of GMA, g;

[0028] w: mass of the weighed dried sample after extraction, g.

[0029] The PBT has an intrinsic viscosity of 1.1-1.5 dl / g.

[0030] The test method for the intrinsic viscosity of PBT is as follows: distilled phenol and o-dichlorobenzene are mixed in a ratio of 3:2 by mass to form a completely homogeneous state, 15 mL of the phenol-o-dichlorobenzene solution is filtered through a sand core funnel, and then filled into a viscometer, and placed in a water bath at 25±0.01℃, and kept for 10 min, then the outflow time of the phenol-o-dichlorobenzene solution is measured, and the average value of 5 measurement values is taken as the outflow time t0 of the pure solvent.

[0031] On an analytical balance, 0.1250±0.0002 g of the cut sample is accurately weighed and placed in a 25 mL volumetric flask. Then 15-20 mL of the mixed solvent of phenol-o-dichlorobenzene is added, heated on a heating plate or steam bath to completely dissolve, taken out, and placed in a water bath at 25±0.01℃ after cooling, kept at constant temperature for 10 min, then the solvent is added to the volumetric flask to the calibration line. The above solution is filtered through a sand core funnel and filled into a viscometer, placed in a constant temperature water bath (25±0.01℃) for 10 min, then the outflow time is measured, repeated three times, and the average value is taken as the outflow time t1 of the solution.

[0032] The calculation formula is as follows:

[0033]

[0034] In the formula: [η] is the intrinsic viscosity, in deciliters per gram (dL / g); t0 is the solvent flow time, in seconds (s); t1 is the solution flow time, in seconds (s); c is the solution concentration, in grams per hundred milliliters (g / 100 ml)

[0035] It also includes 0.05-0.5 parts by weight of an ester exchange inhibitor, which is selected from one or several of sodium hydrogen phosphate, triethanolamine, trimethyl stannate, disodium hydrogen pyrophosphate, triphenyl phosphate, zinc dihydrogen phosphate, etc.

[0036] The anti-dripping agent is selected from polytetrafluoroethylene.

[0037] 0-2 parts of an auxiliary selected from one or more of an antioxidant, a lubricant can be added according to actual needs.

[0038] The preparation method of the flame-retardant PBT / PC composition comprises the following steps: uniformly mixing the components according to the ratio, and extruding and granulating through a double-screw extruder to obtain the flame-retardant PBT / PC composition. The temperature of the first zone is 200-220 DEG C, the temperature of the second zone is 220-230 DEG C, the temperature of the third zone is 230-240 DEG C, the temperature of the fourth zone is 230-240 DEG C, the temperature of the fifth zone is 230-240 DEG C, the temperature of the sixth zone is 230-240 DEG C, the temperature of the seventh zone is 240-250 DEG C, the temperature of the eighth zone is 240-250 DEG C, the temperature of the ninth zone is 230-240 DEG C, and the rotation speed of the main machine is 300-400 r / min.

[0039] The flame-retardant PBT / PC composition is mainly applied in the field of electronic appliances, and is particularly applied in electronic appliances with flame-retardant and low-temperature toughness requirements, such as photovoltaic components and frequency converter shells.

[0040] The present application has the following beneficial effects:

[0041] The present application can reduce the ester exchange reaction with PBT resin to a certain extent by selecting the brominated polycarbonate with specific parameters, and meanwhile, the PBT / brominated polycarbonate / glycidyl methacrylate grafted toughening agent has better compatibility, so that the V-0 flame retardancy can be realized, high low-temperature toughness (notched impact performance at-30 DEG C) can be realized, and the advantage of anti-baking shrinkage is also achieved. DETAILED DESCRIPTION

[0042] The present application will be described in detail below in combination with specific embodiments. The following embodiments will help those skilled in the art to further understand the present application, but do not limit the present application in any form. It should be pointed out that, for those skilled in the art, a number of modifications and improvements can be made without departing from the concept of the present application. These all belong to the protection scope of the present application.

[0043] The raw materials used in the present application are as follows:

[0044] PBT resin-A: the grade is GX121, the intrinsic viscosity is 1.0 dl / g, and the raw material is from the Engineering Plastics Factory of Sinopec Group Asset Management Co., Ltd. Yizheng Branch;

[0045] PBT resin-B: the grade is GL236, the intrinsic viscosity is 1.3 dl / g, and the raw material is from the Engineering Plastics Factory of Sinopec Group Asset Management Co., Ltd. Yizheng Branch;

[0046] Brominated PC-1: molar ratio of bisphenol A: tetrabromobisphenol A is 55:45, viscosity average molecular weight is 26000, self-made;

[0047] Brominated PC-2: molar ratio of bisphenol A: tetrabromobisphenol A is 50:50, viscosity average molecular weight is 23000, self-made;

[0048] Brominated PC-3: molar ratio of bisphenol A: tetrabromobisphenol A is 45:55, viscosity average molecular weight is 18300, self-made;

[0049] Brominated PC-4: molar ratio of bisphenol A: tetrabromobisphenol A is 40:60, viscosity average molecular weight is 14600, self-made;

[0050] Brominated PC-5: molar ratio of bisphenol A: tetrabromobisphenol A is 65:35, viscosity average molecular weight is 43000, self-made;

[0051] Brominated PC-6: molar ratio of bisphenol A: tetrabromobisphenol A is 30:70, viscosity average molecular weight is 10500, self-made;

[0052] The preparation method of the above brominated PC is as follows: a reactor provided with a stirrer, a condenser, a three isocyanate and a sodium hydroxide dropping device is prepared, bisphenol A, tetrabromobisphenol A and 1,2-dichloroethane are added, a sodium hydroxide solution is added under stirring, and after the addition is completed, the solution is stirred until the tetrabromobisphenol A is completely dissolved. Then, a 1,2-dichloroethane solution of three isocyanate is added dropwise. After the dropwise addition is completed, the solution is stirred at 25-30°C for 2-3 hours. After the reaction is completed, the solution is allowed to stand, the organic phase is separated, the organic phase is repeatedly washed with deionized water, and the organic phase is added to methanol for precipitation to obtain the brominated PC. The molar ratio of bisphenol A: tetrabromobisphenol A in the brominated PC is controlled by controlling the amount and molar ratio of bisphenol A and tetrabromobisphenol A.

[0053] Brominated PC-7: tetrabromobisphenol A carbonate oligomer, brand BC-58, bromine content 58%, American Great Lakes Chemical Corporation;

[0054] Toughening agent A: GMA grafted ethylene-methyl acrylate copolymer, GMA grafting rate 0.5wt%, self-made;

[0055] Toughening agent B: GMA grafted ethylene-methyl acrylate copolymer, GMA grafting rate 0.8wt%, self-made;

[0056] Toughening agent C: GMA grafted ethylene-methyl acrylate copolymer, GMA grafting rate 1.3wt%, self-made;

[0057] Toughening agent D: GMA grafted ethylene-methyl acrylate copolymer, GMA grafting rate 2.0wt%, self-made;

[0058] Toughening agent E: Ethylene-methyl acrylate copolymer: ELVALOY AC 1125, DuPont USA;

[0059] Toughening agent F: GMA grafted ethylene-butyl acrylate copolymer: GMA grafting rate is 1.0wt%, self-made;

[0060] The method of the above self-made toughening agent is: glycidyl methacrylate, initiator (the addition amount is 0.3wt% of the total weight of the toughening agent before grafting) dicumyl peroxide, the toughening agent before grafting are uniformly mixed, and then extruded and granulated through a double screw extruder, the screw temperature is 150-180℃, the length-diameter ratio is 44:1, and the above toughening agents A / B / C / D / F are obtained by controlling the amount of glycidyl methacrylate.

[0061] Toughening agent G: Ethylene-butyl acrylate copolymer: ELVALOY AC34035, DuPont USA;

[0062] Zinc dihydrogen phosphate: BUDIT T21, Budenheim, Germany;

[0063] Polytetrafluoroethylene: Anti-dripping agent, commercially available;

[0064] Antioxidant: 1:1 compound of RIANOX 1010 and RIANOX 168, Tianjin Anlon New Material Co., Ltd.;

[0065] Preparation method of flame-retardant PBT / polycarbonate composition of examples and comparative examples: according to the ratio, the components are uniformly mixed, and then extruded and granulated through a double screw extruder to obtain the flame-retardant PBT / PC composition, wherein the temperature of the first zone is 200-220℃, the temperature of the second zone is 220-230℃, the temperature of the third zone is 230-240℃, the temperature of the fourth zone is 230-240℃, the temperature of the fifth zone is 230-240℃, the temperature of the sixth zone is 230-240℃, the temperature of the seventh zone is 240-250℃, the temperature of the eighth zone is 240-250℃, the temperature of the ninth zone is 230-240℃, and the main machine speed is 300-400r / min.

[0066] Test methods:

[0067] (1) Flame retardancy: according to the UL94 standard, 0.8mm sample was injection molded, and the flame retardancy was determined by using a burning box.

[0068] (2) Notched impact strength at-30℃: the PBT / PC alloy material was dried in a dehumidifying drying box at 120℃ for 4h, and then notched impact sample was injection molded according to the standard ASTM D256-2010. The sample was placed in a low temperature box at-30℃ for more than 4h, and then the notched impact strength of the sample was quickly determined after taking out.

[0069] (3) Shrinkage after baking test: injection molding of a rectangular square plate with a cross, the sample size is 220 mm x 60 mm x 2 mm, the length between the two ends of the cross in the mold is 200.07 mm; 200.07 is the length between the two ends of the cross in the shrinkage rate plate mold, the unit is mm, S is the shrinkage rate; Specifically, the cross shrinkage rate plate is placed in a 120°C oven for 2h, and after taking out and adjusting for 24h, the length L2 between the two ends of the cross of the shrinkage rate plate after baking is measured, and the post-shrinkage rate H is calculated according to the following formula; H = (L1-L2) / 200.07*100%; L1 is the length between the two ends of the cross of the shrinkage rate plate before baking.

[0070] Table 1: Weight parts of each component of flame-retardant PBT brominated polycarbonate compositions of Examples 1-6 and test results

[0071] Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 PBT resin-A 40 50 50 50 50 PBT resin-B 60 Brominated PC grade 1 1 1 2 3 4 Brominated PC content 50 35 30 35 35 35 Toughener grade A A A A A A Toughener content 10 13 15 13 13 13 Polytetrafluoroethylene 0.3 0.5 0.2 0.5 0.5 0.5 Zinc dihydrogen phosphate 0.1 0.3 0.5 0.3 0.3 0.3 Antioxidant 0.3 0.3 Flame retardancy V0 V0 V0 V0 V0 V0 -30 °C notched impact strength, kJ / m 2 ]] 8.5 9.6 11.4 9.7 10.1 10.7 Shrinkage H, % 0.36 0.49 0.41 0.34 0.31 0.40

[0072] As can be seen from Examples 2 / 4-6, the average molecular weight range of brominated PC and the molar ratio of bisphenol A: tetra-bromobisphenol A significantly affect the shrinkage and low-temperature toughness of the composition, and the preferred range has lower shrinkage and better low-temperature toughness.

[0073] Table 2: Weight parts of each component of flame-retardant PBT brominated polycarbonate compositions of Examples 7-10 and test results

[0074] Example 7 Example 8 Example 9 Example 10 PBT resin-A 50 50 50 50 Brominated PC grade 1 1 1 1 Brominated PC content 35 35 35 35 Toughener grade B C D F Toughener content 13 13 13 13 Polytetrafluoroethylene 0.5 0.5 0.5 0.5 Zinc dihydrogen phosphate 0.3 0.3 0.3 0.3 Flame retardancy V0 V0 V0 V0 -30 °C notched impact strength, kJ / m 2 ]] 10.2 9.7 9.1 9.6 Shrinkage H, % 0.41 0.38 0.44 0.35

[0075] As can be seen from Examples 2 / 7-10, the preferred content of toughening agent GMA has better low-temperature toughness and shrinkage.

[0076] Table 3: Weight parts of each component of flame-retardant PBT brominated polycarbonate compositions of Comparative Examples and test results

[0077] Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Comparative Example 6 Comparative Example 7 PBT resin-A 50 50 50 50 50 50 50 Brominated PC grade 5 6 7 1 1 1 1 Brominated PC content 35 35 35 35 35 35 35 Toughener grade A A A E G A A Toughener content 13 13 13 13 13 5 23 Polytetrafluoroethylene 0.5 0.5 0.5 0.5 0.5 0.5 0.5 Zinc dihydrogen phosphate 0.3 0.3 0.3 0.3 0.3 0.3 0.3 Flame retardancy V0 V0 V0 V0 V0 V0 V2 -30 °C notched impact strength, kJ / m 2 ]] 7.1 6.4 6.1 5.3 5.4 5.6 10.8 Shrinkage H, % 0.69 0.75 0.96 0.77 0.78 0.43 0.48

[0078] As can be seen from Comparative Examples 1-2, if the molar ratio of bisphenol A: tetra-bromobisphenol A in the brominated PC is not within the range defined in the present application, the low-temperature toughness and shrinkage are both poor.

[0079] As can be seen from Comparative Example 3, when a low-molecular-weight brominated PC is selected, the low-temperature toughness and shrinkage are both worse.

[0080] As can be seen from Comparative Examples 4 / 5, when there is no GMA grafted toughening agent, the low-temperature toughness and shrinkage are both poor.

[0081] As can be seen from Comparative Example 6, when the content of the toughening agent is too low, the low-temperature toughness is poor.

[0082] As can be seen from Comparative Example 7, when the content of the toughening agent is too high, the flame retardancy does not reach V-0.

[0083] From the above examples and comparative examples, it can be seen that the flame-retardant PBT brominated polycarbonate composition of the present application has a notched impact strength at -30°C > 8 kJ / m2 2 , and a shrinkage H less than 0.5%.

Claims

1. A flame retardant PBT / brominated polycarbonate composition characterized in that, By weight parts, comprising the following components: PBT 40-60 parts; Brominated polycarbonate 30-50 parts; Anti-dripping agent 0.2-0.5 parts; Glycidyl methacrylate grafted toughening agent 10-15 parts; The viscosity average molecular weight of the brominated polycarbonate is in the range of 13000-30000, and the molar ratio of bisphenol A: tetra-bromobisphenol A is (55-40): (45-60); The glycidyl methacrylate grafted toughening agent is at least one selected from glycidyl methacrylate grafted ethylene-methyl acrylate copolymer toughening agent, glycidyl methacrylate grafted ethylene-butyl acrylate copolymer toughening agent.

2. The flame retardant PBT / brominated polycarbonate composition according to claim 1, characterized in that, The viscosity average molecular weight of the brominated polycarbonate is in the range of 17000-24000, and the molar ratio of bisphenol A: tetra-bromobisphenol A is (50-45): (50-55).

3. The flame retardant PBT / brominated polycarbonate composition according to claim 1, characterized in that, The grafting rate of glycidyl methacrylate in the glycidyl methacrylate grafted toughening agent is 0.4-2.1wt%.

4. The flame retardant PBT / brominated polycarbonate composition according to claim 3, characterized in that, The grafting rate of glycidyl methacrylate in the glycidyl methacrylate grafted toughening agent is 0.8-1.3wt%.

5. The flame retardant PBT / brominated polycarbonate composition according to claim 1, characterized in that, The intrinsic viscosity of the PBT is 1.1-1.5dl / g.

6. The flame retardant PBT / brominated polycarbonate composition according to claim 1, characterized in that, By weight parts, further comprising 0.05-0.5 parts of transesterification inhibitor, the transesterification inhibitor is at least one selected from zinc dihydrogen phosphate, sodium hydrogen phosphate, triethanolamine, trimethyl tin acid ester, disodium pyrophosphate, triphenyl phosphate.

7. The flame retardant PBT / brominated polycarbonate composition according to claim 1, characterized in that, The anti-dripping agent is polytetrafluoroethylene.

8. The flame retardant PBT / brominated polycarbonate composition according to claim 1, characterized in that, By weight parts, further comprising 0-2 parts of auxiliary, the auxiliary is one or more selected from antioxidants, lubricants.

9. Process for the preparation of the flame-retardant PBT / brominated polycarbonate composition according to any one of claims 1 to 8, characterized in that, Comprising the following steps: according to the ratio, mix each component uniformly, extrude and granulate through a double screw extruder to obtain a flame-retardant PBT / brominated polycarbonate composition.

10. Use of the flame-retardant PBT / brominated polycarbonate composition according to any one of claims 1 to 8, characterized in that, For preparing a flame-retardant product. For preparing a flame-retardant product.