A preparation process for maleic anhydride-grafted POE-compatible modified high-temperature flame-retardant PC / ABS alloy resin

Abstract

This invention relates to the field of flame-retardant polymer materials technology, specifically a process for preparing high-temperature flame-retardant PC / ABS alloy resin modified with maleic anhydride-grafted POE. The modification of PC / ABS alloys to achieve high heat resistance and halogen-free flame retardancy often presents the technical challenge of synergistically improving heat resistance, toughness, and flame retardancy. This invention employs a synergistically optimized preparation process. A specific step-feeding melt-blending extrusion strategy is used, where PC and heat-resistant ABS, with maleic anhydride-grafted POE as the core compatibilizer, are melt-blended. After sufficient plasticization and the initial formation of a stable phase structure, a heat-sensitive halogen-free phosphorus-based flame retardant and an anti-dripping agent are injected. This avoids premature decomposition and failure of the flame retardant at high temperatures, ensures sufficient reaction of POE-g-MAH at the PC / ABS phase interface, optimizes the dispersed phase morphology, enhances the low-temperature impact toughness and stress cracking resistance of the PC / ABS alloy resin, and solves the material brittleness problem caused by the introduction of flame retardants.

Description

Technical Field

[0001] This invention relates to the field of polymer materials technology, and in particular to the preparation process of high-temperature flame-retardant PC / ABS alloy resin modified with maleic anhydride grafted with POE. Background Technology

[0002] PC / ABS alloy, as a high-performance engineering plastic, naturally combines the excellent impact toughness, heat resistance, and dimensional stability of polycarbonate (PC) with the good processing flow, rigidity, and surface gloss of ABS resin, making it one of the platform materials in the field of modified plastics. Based on its inherent advantages in high toughness and processability, it has become an ideal choice for automotive interior and exterior parts, 5G communication equipment, and high-end electronic appliance housings, where higher heat resistance and environmentally friendly halogen-free flame retardancy are required. Current technologies typically employ the addition of phosphorus-based flame retardants (such as BDP) to achieve halogen-free flame retardancy, and introduce maleic anhydride-grafted elastomers (such as POE-g-MAH) as compatibilizers to compensate for the loss of fracture resistance under external impact due to the increased complexity of the blending system. While these technical approaches are theoretically feasible, in actual industrial production, especially in continuous melt blending extrusion processes, there are still insurmountable process contradictions.

[0003] In the industrial-scale continuous production of the above components through melt blending, a key challenge arises: how to design an extrusion process that provides sufficient energy and reaction time for the compatibilizer system, which requires high temperatures for effective chemical reactions, while simultaneously preventing other heat- and shear-sensitive functional additives (such as phosphorus-based flame retardants) from prematurely decomposing and failing due to prolonged exposure to the processing environment. Traditional one-step blending processes often struggle to balance this contradiction. While high temperatures and strong shear are beneficial for compatibilization reactions, they can easily lead to flame retardant degradation, resulting in unstable flame retardant performance, appearance defects, and even decreased mechanical properties in the final product. Conversely, using milder process conditions to protect the flame retardant significantly reduces the interfacial compatibilization effect of the compatibilizer, failing to effectively address the material's toughness issues. Therefore, developing a novel preparation process that cleverly balances the varying processing requirements of different components has become a critical technological bottleneck for achieving stable production of high-performance PC / ABS alloys. Summary of the Invention

[0004] In view of the aforementioned existing problems, the present invention is proposed.

[0005] Therefore, in order to solve the technical problem that PC / ABS alloys are difficult to achieve high heat resistance, high impact toughness and efficient halogen-free flame retardancy in the existing technology, the present invention provides a preparation process for high temperature flame retardant PC / ABS alloy resin modified with maleic anhydride grafted with POE.

[0006] To solve the above-mentioned technical problems, the present invention provides the following technical solution:

[0007] This invention provides a process for preparing a high-temperature flame-retardant PC / ABS alloy resin with maleic anhydride-grafted POE compatibility modification, comprising the following steps. The raw materials include the following components: high-heat-resistant polycarbonate, heat-resistant acrylonitrile-butadiene-styrene copolymer, maleic anhydride-grafted polyolefin elastomer, bisphenol A bis(diphenyl phosphate), polytetrafluoroethylene, antioxidant 1076, antioxidant 168, and pentaerythritol stearate. The invention is characterized by the following steps:

[0008] S1 Raw Material Drying Treatment: High heat-resistant polycarbonate, heat-resistant acrylonitrile-butadiene-styrene copolymer resin, maleic anhydride grafted polyolefin elastomer, antioxidant 1076, antioxidant 168, polytetrafluoroethylene powder, and pentaerythritol stearate are dried.

[0009] S2 Precision Feeding: Dry high heat-resistant polycarbonate granules, heat-resistant acrylonitrile-butadiene-styrene copolymer granules, maleic anhydride grafted polyolefin elastomer toughening agent, antioxidant 1076, antioxidant 168 and pentaerythritol stearate are added to the main feed port of the extruder, and bisphenol A bis(diphenyl phosphate) and polytetrafluoroethylene are added to the side feed port to obtain polymer raw materials;

[0010] S3 melt blending extrusion: Controlling a co-rotating twin-screw extruder to melt and shear the polymer raw materials, promoting the micro-dispersion and interfacial compatibility of each component; vacuum degassing the formed melt to remove volatiles; homogenizing the melt and establishing stable pressure for extrusion molding;

[0011] S4 Pelletizing, Cooling and Pelletizing: The homogeneous melt is extruded through a multi-hole template in the die head, then cooled and shaped, dried and pelletized.

[0012] S5 Post-processing and Packaging: The cut granules are screened and homogenized, and qualified granules are bagged and stored.

[0013] As a preferred embodiment of the preparation process of the maleic anhydride-grafted POE-compatible modified high-temperature flame-retardant PC / ABS alloy resin described in this invention, the following raw materials are prepared in parts by weight: 50-75 parts of high heat-resistant polycarbonate; 15-35 parts of heat-resistant acrylonitrile-butadiene-styrene copolymer; 5-12 parts of maleic anhydride-grafted polyolefin elastomer; 10-18 parts of bisphenol A bis(diphenyl phosphate); 0.3-1.0 parts of polytetrafluoroethylene; and 0.1-0 parts of antioxidant 1076. 0.3 parts; antioxidant 168 is 0.2-0.5 parts; pentaerythritol stearate is 0.5-1.5 parts; wherein, the specific weight parts of raw materials are: 65 parts of high heat-resistant polycarbonate; 25 parts of heat-resistant acrylonitrile-butadiene-styrene copolymer; 8 parts of maleic anhydride grafted polyolefin elastomer; 15 parts of bisphenol A bis(diphenyl phosphate); 0.5 parts of polytetrafluoroethylene; antioxidant 1076 is 0.17 parts, antioxidant 168 is 0.33 parts; pentaerythritol stearate is 1.0 part.

[0014] As a preferred embodiment of the preparation process of the maleic anhydride-grafted POE-compatible modified high-temperature flame-retardant PC / ABS alloy resin described in this invention, the melt index (300℃, 1.2kg) of the high heat-resistant polycarbonate is 5-15g / 10min, and the Vicat softening point is not lower than 145℃; the Vicat softening point of the heat-resistant ABS resin is not lower than 105℃; and the grafting rate of maleic anhydride in the maleic anhydride-grafted polyolefin elastomer is between 0.8-1.5wt%.

[0015] As a preferred embodiment of the preparation process of the maleic anhydride-grafted POE-compatible modified high-temperature flame-retardant PC / ABS alloy resin described in this invention, the following steps are taken: Heat-resistant polycarbonate, heat-resistant acrylonitrile-butadiene-styrene copolymer resin, maleic anhydride-grafted polyolefin elastomer, antioxidant 1076, antioxidant 168, polytetrafluoroethylene powder, and pentaerythritol stearate are dried.

[0016] After drying, the moisture content of each raw material is as follows: less than 0.02% for high heat-resistant polycarbonate; less than 0.01% for heat-resistant acrylonitrile-butadiene-styrene copolymer; less than 0.01% for maleic anhydride-grafted polyolefin elastomer; and less than 0.05% for polytetrafluoroethylene.

[0017] As a preferred embodiment of the preparation process of the maleic anhydride-grafted POE compatibility-modified high-temperature flame-retardant PC / ABS alloy resin described in this invention, the following steps are taken: dried high-heat-resistant polycarbonate particles, heat-resistant acrylonitrile-butadiene-styrene copolymer particles, maleic anhydride-grafted polyolefin elastomer toughening agent, antioxidant 1076, antioxidant 168, and pentaerythritol stearate are added to the main feed port of the extruder, and bisphenol A bis(diphenyl phosphate) and polytetrafluoroethylene are added to the side feed port to obtain the polymer raw material. The specific steps are as follows:

[0018] Dry high-heat-resistant polycarbonate, heat-resistant ABS resin, maleic anhydride-grafted polyolefin elastomer, antioxidant 1076, antioxidant 168, and pentaerythritol stearate are premixed in a high-speed mixer for 5-10 minutes to form premix A. Premix A is added to the main feed port of a co-rotating twin-screw extruder. Liquid bisphenol A bis(diphenyl phosphate) and polytetrafluoroethylene powder are pre-dispersed in a shear tank for 15-30 minutes, with the rotation speed of the shear tank controlled at 800-1200 rpm, to form a uniform suspension B, which is then added to the side feed port of the extruder.

[0019] As a preferred embodiment of the preparation process of maleic anhydride-grafted POE-compatible modified high-temperature flame-retardant PC / ABS alloy resin according to the present invention, wherein: the screw speed of the co-rotating twin-screw extruder is controlled at 400-600 rpm; the temperature of each heating zone of the extruder from the feeding port to the die head is set as follows: Zone 1 (feeding section): 200-220℃; Zones 2 to 4 (melting and plasticizing section): 240-260℃; Zone 5 (side feeding port section): 230-250℃; Zones 6 and 7 (reaction and dispersion section): 260-280℃; Zone 8 (vacuum exhaust section): 250-270℃; Zones 9 and 10 (homogenization and pressure building section): 240-260℃; Die head temperature: 250-270℃; The residence time of the material in the high-temperature and high-shear reaction section of Zones 6 and 7 is 15-25 seconds to ensure that the maleic anhydride groups and the end groups in PC and ABS undergo sufficient interfacial reaction; Vacuum exhaust is set in Zone 8, and the vacuum degree is not lower than -0.08MPa.

[0020] As a preferred embodiment of the preparation process of maleic anhydride-grafted POE compatibility-modified high-temperature flame-retardant PC / ABS alloy resin described in this invention, the process includes: feeding in zone one, where the main solid raw materials such as PC and ABS are first fed in and preheated to prepare for subsequent melting, reaction, and the addition of additives at the side opening; feeding in zone five, where after the PC / ABS melt base is formed, a heat-sensitive flame retardant is injected, which protects the flame retardant from decomposition and ensures the best reaction effect of the compatibility agent; and vacuuming in zone eight, where, after the melt has fully reacted and before extrusion molding, moisture, air, and volatile substances such as reaction byproducts are removed to ensure that the final product is free of bubbles and defects.

[0021] As a preferred embodiment of the preparation process of maleic anhydride-grafted POE-compatible modified high-temperature flame-retardant PC / ABS alloy resin described in this invention, the process of strip drawing, cooling and pelletizing specifically includes: extruding the homogeneous melt into strips through a multi-hole template of the die head, cooling and shaping it in a cold water bath at a water temperature of 50-70℃, removing surface moisture through a drying device, and then pelletizing it.

[0022] As a preferred embodiment of the preparation process of maleic anhydride-grafted POE-compatible modified high-temperature flame-retardant PC / ABS alloy resin described in this invention, the post-processing and packaging specifically include: drying the cut granules at 80-100℃ for 2-4 hours to eliminate internal stress and further reduce moisture content, and then screening, homogenizing and mixing before vacuum packaging and warehousing.

[0023] The beneficial effects of this invention are:

[0024] This invention employs a step-by-step feeding strategy, first thoroughly mixing PC, ABS, and a compatibilizer in a high-temperature environment, then adding a heat-sensitive flame retardant in a relatively milder environment. This provides an "optimal processing window" for materials with different requirements, ensuring that the compatibilizer can undergo a sufficient interfacial chemical reaction with PC / ABS at high temperatures, thereby strengthening the interfacial bonding and solving the material brittleness problem. By injecting the flame retardant into the formed melt, thermal decomposition under processing conditions is effectively avoided, ensuring stable flame retardant properties and excellent heat resistance in the final product. Therefore, this invention resolves the technical contradiction of simultaneously achieving toughness, heat resistance, and flame retardancy in the modification process of PC / ABS alloys. Attached Figure Description

[0025] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 This is a flowchart illustrating the preparation process of the alloy resin of this invention. Detailed Implementation

[0027] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0028] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0029] Secondly, the term "one embodiment" or "example" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the invention. The appearance of an embodiment in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that mutually excludes other embodiments.

[0030] The following embodiments of the present invention and the comparative examples illustrate the preparation methods of maleic anhydride-grafted POE-compatible modified high-temperature flame-retardant PC / ABS alloy resin, as shown below:

[0031] Reference Figure 1 As one embodiment of the present invention, this embodiment provides a preparation process for maleic anhydride-grafted POE-compatible modified high-temperature flame-retardant PC / ABS alloy resin, the preparation method comprising the following steps:

[0032] Step 1: Raw Material Preparation: Weigh the following raw materials according to weight: 65 parts of high heat-resistant polycarbonate (PC); 25 parts of heat-resistant acrylonitrile-butadiene-styrene copolymer (ABS); 8 parts of maleic anhydride-grafted polyolefin elastomer (POE-g-MAH); 15 parts of bisphenol A bis(diphenyl phosphate) (BDP); 0.5 parts of polytetrafluoroethylene (PTFE); 0.17 parts of antioxidant 1076; 0.33 parts of antioxidant 168; and 1.0 part of pentaerythritol stearate. The Vicat softening point of the high heat-resistant polycarbonate is 148℃; the Vicat softening point of the heat-resistant ABS resin is 107℃; and the grafting rate of maleic anhydride in the maleic anhydride-grafted polyolefin elastomer is 1.0 wt%.

[0033] Step 2, Raw Material Processing and Feeding: High-heat-resistant polycarbonate is dried at 125°C for 5 hours; heat-resistant ABS resin and maleic anhydride-grafted polyolefin elastomer are dried at 85°C for 4 hours. The dried polycarbonate, ABS, maleic anhydride-grafted polyolefin elastomer, powdered antioxidant, and pentaerythritol stearate are added to a high-speed mixer and premixed for 5 minutes. Then, the mixture is fed into the main feed port of a co-rotating twin-screw extruder via a loss-in-weight feeder. Liquid bisphenol A (diphenyl phosphate) and polytetrafluoroethylene powder are pre-dispersed in a shear tank at 1000 rpm for 20 minutes to form a suspension, which is then added to the side feed port of the extruder via a metering pump.

[0034] Step 3: Melt Blending Extrusion: Control the screw speed of the co-rotating twin-screw extruder (L / D ratio L / D=40) at 450 rpm. Set the temperatures for each zone as follows: Zone 1 220℃, Zones 2-4 250℃, Zone 5 240℃, Zones 6-7 (reaction and dispersion section) 275℃, Zone 8 265℃, Zones 9-10 255℃, and the die head 260℃. The material undergoes melting, dispersion, and interfacial compatibility reactions under high temperature and strong shear, and volatiles are removed through a vacuum exhaust section with a vacuum degree of -0.08 MPa.

[0035] Step 4, Post-processing: The extruded strips are cooled and dried in a 60°C water bath, then granulated. The resulting particles are then dried at 90°C for 3 hours.

[0036] Testing revealed that the alloy resin particles obtained in this embodiment were uniformly milky white with a smooth surface. Their cantilever beam notched impact strength (-30℃) was... The heat distortion temperature was 118°C, and it passed the UL94V-0 flammability test. This sample was used as a benchmark for evaluating the overall performance of subsequent examples and comparative examples.

[0037] The preparation method of a maleic anhydride-grafted POE-compatible modified high-temperature flame-retardant PC / ABS alloy resin includes the following steps:

[0038] Step 1: Raw Material Preparation: Weigh the following raw materials according to weight: 55 parts high heat-resistant polycarbonate; 35 parts heat-resistant acrylonitrile-butadiene-styrene copolymer; 12 parts maleic anhydride-grafted polyolefin elastomer; 12 parts bisphenol A bis(diphenyl phosphate); 0.5 parts polytetrafluoroethylene; 0.5 parts of antioxidant 1076 and antioxidant 168 combined; 1.0 part pentaerythritol stearate. The key parameters of each raw material are the same as in Example 1, and the conditions of the remaining steps are consistent with those in Example 1.

[0039] Testing revealed that this embodiment explored the possibility of achieving higher toughness by increasing the content of ABS and POE-g-MAH. The resulting alloy resin exhibited an increased cantilever beam notched impact strength (-30°C) to [value missing]. It exhibits superior toughness, but the heat distortion temperature drops slightly to 115℃, and it also passes the UL94V-0 flammability test.

[0040] The preparation method of a maleic anhydride-grafted POE-compatible modified high-temperature flame-retardant PC / ABS alloy resin includes the following steps:

[0041] Step 1: Raw Material Preparation: Weigh the following raw materials according to weight: 70 parts high heat-resistant polycarbonate; 18 parts heat-resistant acrylonitrile-butadiene-styrene copolymer; 6 parts maleic anhydride-grafted polyolefin elastomer; 17 parts bisphenol A bis(diphenyl phosphate); 0.5 parts polytetrafluoroethylene; 0.5 parts of antioxidant 1076 and antioxidant 168 combined; 1.0 part pentaerythritol stearate. The key parameters of each raw material are the same as in Example 1, and the conditions of the remaining steps are consistent with those in Example 1.

[0042] Testing revealed that this embodiment explored the possibility of achieving higher heat resistance by increasing the PC content. The resulting alloy resin exhibited a heat distortion temperature increased to 122°C, demonstrating exceptionally high heat resistance. Its cantilever beam notched impact strength (-30°C) was [missing value]. It still maintains a good level of toughness and has passed the UL94V-0 flammability test.

[0043] A method for preparing a PC / ABS alloy resin includes the following steps:

[0044] The preparation method is basically the same as in Example 1, except that in the raw material ratio of step one, the grafting rate of maleic anhydride in the maleic anhydride-grafted polyolefin elastomer is only 0.3 wt%. All other conditions are consistent with those in Example 1.

[0045] Testing revealed that due to the excessively low grafting rate (0.3wt%) and extremely poor compatibility, the cantilever beam notched impact strength (-30℃) of the resulting alloy resin was only [value missing]. The injection-molded specimen showed a smooth fracture surface during the impact test, exhibiting brittle fracture characteristics.

[0046] A method for preparing a PC / ABS alloy resin includes the following steps:

[0047] The preparation method is basically the same as in Example 1, except that the grafting rate of maleic anhydride in the maleic anhydride-grafted polyolefin elastomer used in step one is increased to 2.5 wt%. All other raw materials, proportions and process parameters are consistent with those in Example 1.

[0048] Testing revealed that the excessively high grafting rate (2.5 wt%) caused slight cross-linking of POE-g-MAH itself, resulting in poor dispersibility. Furthermore, the excessive number of active sites may have caused side reactions in the PC. Consequently, the low-temperature impact toughness of the final product significantly decreased. Furthermore, the melt flow index of the material decreases, resulting in poorer processing fluidity.

[0049] A method for preparing a PC / ABS alloy resin includes the following steps:

[0050] The preparation method is basically the same as in Example 1, except for step three, melt blending extrusion: the screw speed of the co-rotating twin-screw extruder (L / D ratio L / D=40) is controlled at 450 rpm, and the temperatures of each zone are set as follows: Zone 1 220℃, Zones 2-4 250℃, Zone 5 240℃, Zones 6-7 240℃, Zone 8 235℃, Zones 9-10 230℃, and the die head 235℃. The material is melted and dispersed under shear, and volatiles are removed by a vacuum exhaust section with a vacuum degree of -0.08MPa.

[0051] Testing revealed that due to insufficient reaction temperature (240℃) and incomplete interfacial reaction, the cantilever beam notched impact strength (-30℃) of the resulting alloy resin decreased significantly. It also exhibits obvious brittleness.

[0052] The preparation method of a PC / ABS alloy resin is basically the same as that in Example 1, except that in the raw material preparation in step one: the same raw materials as in Example 1 are weighed according to the weight parts, and the POE-g-MAH grafting rate is also 1.0 wt%. The raw materials used are ordinary polycarbonate (Vicat softening point 142℃) and ordinary ABS resin (Vicat softening point 94℃). In the raw material treatment and feeding step two, the ordinary polycarbonate is dried at 120℃ for 5 hours, and the ordinary ABS resin and maleic anhydride grafted polyolefin elastomer are dried at 80℃ for 4 hours. The remaining feeding operations and step conditions are consistent with those in Example 1.

[0053] Testing revealed that, due to the use of ordinary grade PC and ABS, the heat distortion temperature of the resulting alloy resin was only 101°C, far below the high-temperature resistance requirement of this invention, although its impact performance was acceptable.

[0054] The preparation method of a PC / ABS alloy resin is basically the same as that in Example 1, except that in the raw material ratio of step one, the amount of high heat-resistant polycarbonate is adjusted to 58 parts, and the amount of bisphenol A bis(diphenyl phosphate) (BDP) is increased to 22 parts. The amounts of all other components and the preparation conditions are the same as in Example 1.

[0055] Testing revealed that due to the strong plasticizing effect of excessive BDP (22 parts), the heat distortion temperature (HDT) of the resulting alloy resin decreased significantly from 118°C in Example 1 to 108°C, failing to meet the high heat resistance requirements.

[0056] The preparation method of a PC / ABS alloy resin is basically the same as that in Example 1, except that in the raw material ratio of step one, the amount of high heat-resistant polycarbonate is adjusted to 72 parts, and the amount of bisphenol A bis(diphenyl phosphate) (BDP) is reduced to 8 parts. The amounts of all other components and the preparation conditions are the same as in Example 1.

[0057] Testing revealed that due to insufficient BDP dosage (8 parts), the resulting alloy resin could not pass the V-0 rating in the vertical combustion test and could only reach the V-1 rating, thus failing to achieve the goal of high-efficiency flame retardancy.

[0058] The preparation method of a PC / ABS alloy resin is basically the same as that in Example 1, except that in the raw material ratio of step one, the amount of high heat-resistant polycarbonate is adjusted to 70 parts, and the amount of maleic anhydride grafted polyolefin elastomer (POE-g-MAH) is reduced to 3 parts. The amounts of all other components and the preparation conditions are the same as in Example 1.

[0059] Testing revealed that due to insufficient compatibilizer (3 parts), an effective interfacial network could not be formed, resulting in a sharp decrease in the cantilever beam notched impact strength (-30℃) of the obtained alloy resin. Furthermore, the flammability rating dropped to V-2, indicating that compatibility also affects the stability of the flame retardant system.

[0060] The preparation method of a PC / ABS alloy resin is basically the same as that in Example 1, except that in the raw material ratio of step one, the amount of high heat-resistant polycarbonate is adjusted to 55 parts, and the amount of maleic anhydride grafted polyolefin elastomer (POE-g-MAH) is increased to 18 parts. The amounts of all other components and the preparation conditions are the same as in Example 1.

[0061] Testing revealed that excessive POE-g-MAH (18 parts) had a significant plasticizing effect on the matrix resin, resulting in a substantial decrease in the rigidity and heat resistance of the resulting alloy resin, with its heat distortion temperature (HDT) dropping to 105℃.

[0062] The preparation method of a PC / ABS alloy resin is basically the same as that in Example 1, except that the screw speed is increased to 700 rpm in the melt blending extrusion process of step three. All other conditions are consistent with those in Example 1.

[0063] During the extrusion process, an excessively high rotation speed of 700 rpm was observed, resulting in a rough surface on the melt strip, exhibiting a "sharkskin" effect. Testing revealed that excessive shear heat had caused polymer degradation, leading to a drop in the heat distortion temperature of the resulting alloy resin to 110°C, and a significant decrease in low-temperature impact toughness.

[0064] The preparation method of a PC / ABS alloy resin is basically the same as that in Example 1, except that the screw speed is reduced to 200 rpm in the melt blending extrusion process in step three.

[0065] Testing revealed that the excessively low rotation speed of 200 rpm provided insufficient shear force, resulting in uneven dispersion of the components (especially PTFE). Although the final product's mechanical properties were acceptable, it melted and dripped during vertical burning tests because the PTFE failed to form an effective network, causing the flame retardant rating to drop to V-2.

[0066] The preparation method of a PC / ABS alloy resin is basically the same as that in Example 1, except for the feeding method in step two: all dried raw materials, including PC, ABS, POE-g-MAH, BDP, PTFE and all additives, are premixed in a high-speed mixer for 5 minutes, and then fed into the extruder together from the main feed port. All other conditions, including raw material ratios and extrusion process parameters, are consistent with those in Example 1.

[0067] This comparative example aims to simulate the traditional "one-step" process. A slight darkening of the melt color was observed during extrusion. Testing revealed that due to the premature thermal decomposition of the heat-sensitive BDP, which interfered with the compatibility reaction, the heat distortion temperature of the resulting alloy resin decreased to 112°C, and its low-temperature impact toughness was significantly lower than that of the example. .

[0068] The preparation method of a PC / ABS alloy resin is basically the same as that in Example 1, except that polytetrafluoroethylene (PTFE) is not added in the raw material preparation step one. The amounts and preparation conditions of all other components are consistent with those in Example 1.

[0069] Testing revealed that although the material had good mechanical and thermal properties, it melted and dripped during the vertical burning test, igniting the degreased cotton below. Therefore, its flammability rating could only be V-2.

[0070] Performance testing:

[0071] The alloy resin particles obtained in Examples 1-3 and Comparative Examples 1-12 were injection molded into standard specimens using an injection molding machine, and their performance was tested according to the standard. The comprehensive results are summarized in the table below.

[0072] Notched impact strength of cantilever beam: tested according to ASTM D256 standard;

[0073] (2) Heat distortion temperature (HDT): Tested according to ASTM D648 standard (1.8 MPa load);

[0074] (3) Vertical flammability rating: According to the UL94 standard (1.6mm thickness), the V-0 rating is higher than the V-2 rating, with better flame retardant performance and lighter burning.

[0075]

[0076] Comprehensive analysis and determination of the final optimal solution:

[0077] Through the above series of embodiments and comparative experiments, the present invention now conducts a comprehensive analysis and weighing of all experimental results, and finally determines the preferred technical solution of the present invention.

[0078] I. Comprehensive Analysis

[0079] The core of this invention lies in systematically solving the performance balance problem between high heat resistance, toughness and high efficiency halogen-free flame retardancy through specific raw material selection, proportion range and innovative step-by-step feeding process.

[0080] 1. Synergistic effect analysis of raw material selection and proportioning:

[0081] Main resin (Comparative Example 4): The results show that using high heat-resistant PC (Vicat softening point not lower than 145℃) and heat-resistant ABS (Vicat softening point not lower than 105℃) is a necessary prerequisite for achieving a high heat distortion temperature (HDT>110℃) in the final product.

[0082] Compatibilizer POE-g-MAH (Comparative Examples 1, 2, 7, 8): Data confirms that maleic anhydride grafting rates between 0.8-1.5 wt% and dosages between 5-12 parts by weight are effective in constructing strong and tough interfacial phases and achieving excellent low-temperature impact toughness. The optimal technical window without excessively sacrificing material rigidity and heat resistance.

[0083] Flame retardant system (comparative examples 5, 6, 12): The amount of BDP used is 10-18 parts by weight, which is the key to stably achieving UL94V-0 flame retardancy and avoiding excessive plasticization that leads to a decrease in HDT; while the addition of PTFE is a necessary guarantee to prevent burning drips and pass the V-0 test.

[0084] Formula Balance (Examples 1-3): The results of Examples 1-3 clearly demonstrate that by adjusting the PC / ABS ratio, it is possible to achieve both high heat resistance (e.g., Example 3, HDT reaches 122℃) and ultra-high toughness (e.g., Example 2, impact strength at -30℃ reaches...). The two are regulated between each other, while Example 1 represents the optimal balance between the two.

[0085] 2. Analysis of the decisive role of preparation process:

[0086] Stepwise feeding process (Comparative Example 11): Comparative Example 11 uses the traditional "one-step" blending method. Even though the raw material formulation is exactly the same as that of Example 1, its low-temperature impact toughness is... It is also far inferior to Example 1. This proves that the stepwise feeding strategy adopted in this invention, which involves melting the main resin and compatibilizer first and then injecting the heat-sensitive flame retardant, is the core technology to avoid flame retardant degradation and ensure sufficient compatibility reaction, and is the decisive factor in achieving the final high performance.

[0087] Process parameters (Comparative Examples 3, 9, 10): The results show that the temperature of the reaction dispersion section needs to reach 260-280℃ to ensure the efficiency of the interfacial reaction; the screw speed needs to be between 400-600 rpm to provide sufficient dispersion shear force and avoid degradation.

[0088] II. Determination of the Optimal Solution

[0089] Based on the above analysis, a preferred technical solution of the present invention is as follows:

[0090] 1. Preferred formula (by weight):

[0091] 65 parts of high heat-resistant polycarbonate; 25 parts of heat-resistant acrylonitrile-butadiene-styrene copolymer; 8 parts of maleic anhydride-grafted polyolefin elastomer with a maleic anhydride grafting rate of approximately 1.0 wt%; 15 parts of bisphenol A-bis(diphenyl phosphate); 0.5 parts of polytetrafluoroethylene; 0.5 parts of antioxidant 1076 and antioxidant 168 combined; 1.0 part of pentaerythritol stearate.

[0092] 2. Optimized process flow:

[0093] A co-rotating twin-screw extrusion process with step-feeding is employed. Dried PC, ABS, POE-g-MAH, and solid additives are added through the main feed port; a suspension formed by pre-dispersed BDP and PTFE is injected through a side feed port in the middle section of the barrel. The temperature of the extruder's reaction and dispersion section is controlled at 270-275℃, the screw speed at approximately 450 rpm, and a vacuum of at least -0.08 MPa is maintained for exhaust. After water cooling and pelletizing, the extruded material undergoes post-drying at 90-100℃.

[0094] The alloy resin prepared by this preferred embodiment (i.e., Example 1) exhibits excellent heat distortion temperature (118°C) and low-temperature impact toughness. A comprehensive balance is achieved between the three properties: halogen-free flame retardancy (UL94V-0 rating), which embodies the technical concept and beneficial effects of the present invention and is the best implementation method for achieving stable and efficient industrial production of this high-performance alloy resin.

[0095] In summary, the step-by-step feeding strategy employed in this invention involves first thoroughly mixing PC, ABS, and the compatibilizer in a high-temperature environment, and then adding a heat-sensitive flame retardant in a relatively milder environment. This provides an "optimal processing window" for materials with different requirements, ensuring that the compatibilizer can undergo a sufficient interfacial chemical reaction with PC / ABS at high temperatures, thereby strengthening the interfacial bonding and solving the material brittleness problem. By injecting the flame retardant into the formed melt, thermal decomposition under processing conditions is effectively avoided, ensuring stable flame retardant properties and excellent heat resistance in the final product. Therefore, this invention resolves the technical contradiction of simultaneously achieving toughness, heat resistance, and flame retardancy in the modification process of PC / ABS alloys.

[0096] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A process for the preparation of a maleic anhydride grafted POE compatibilized modified high temperature resistant flame retardant PC / ABS alloy resin, characterized in that, By weight, the raw materials comprise the following components: 65 parts of high heat-resistant polycarbonate; 25 parts of heat-resistant acrylonitrile-butadiene-styrene copolymer; 8 parts of maleic anhydride-grafted polyolefin elastomer; 15 parts of bisphenol A bis(diphenyl phosphate); 0.5 parts of polytetrafluoroethylene; 0.17 parts of antioxidant 1076; 0.33 parts of antioxidant 168; and 1.0 part of pentaerythritol stearate. The high heat-resistant polycarbonate has a Vicat softening point of not less than 145°C, and the heat-resistant acrylonitrile-butadiene-styrene copolymer has a Vicat softening point of not less than 105°C. The process includes the following steps: S1 Raw Material Drying Treatment: High heat-resistant polycarbonate, heat-resistant acrylonitrile-butadiene-styrene copolymer resin, maleic anhydride grafted polyolefin elastomer, antioxidant 1076, antioxidant 168, polytetrafluoroethylene powder, and pentaerythritol stearate are dried. S2 Precision Feeding: Dry high heat-resistant polycarbonate granules, heat-resistant acrylonitrile-butadiene-styrene copolymer granules, maleic anhydride grafted polyolefin elastomer, antioxidant 1076, antioxidant 168 and pentaerythritol stearate are added to the main feed port of the extruder, and bisphenol A bis(diphenyl phosphate) and polytetrafluoroethylene are added to the side feed port to obtain polymer raw materials; S3 melt blending extrusion: Controlling a co-rotating twin-screw extruder to melt and shear the polymer raw materials, promoting the micro-dispersion and interfacial compatibility of each component; vacuum degassing the formed melt to remove volatiles; homogenizing the melt and establishing stable pressure for extrusion molding; S4 Pelletizing, Cooling and Pelletizing: The homogeneous melt is extruded through a multi-hole template in the die head, cooled and shaped, then dried and pelletized. S5 Post-processing and Packaging: The cut granules are screened and homogenized, and qualified granules are bagged and stored.

2. The process for preparing a maleic anhydride grafted POE compatibilized modified high temperature resistant flame retardant PC / ABS alloy resin according to claim 1, characterized in that, The high heat-resistant polycarbonate has a melt index of 5-15 g / 10 min at 300℃ and 1.2 kg, and a Vicat softening point of not less than 145℃; the heat-resistant acrylonitrile-butadiene-styrene copolymer has a Vicat softening point of not less than 105℃; and the maleic anhydride grafting rate in the maleic anhydride grafted polyolefin elastomer is between 0.8-1.5 wt%.

3. The preparation process of maleic anhydride-grafted POE-compatible modified high-temperature flame-retardant PC / ABS alloy resin according to claim 1, characterized in that, The specific steps of the raw material drying process in step S1 include: after drying, the moisture content of each raw material is as follows: less than 0.02% for high heat-resistant polycarbonate; less than 0.01% for heat-resistant acrylonitrile-butadiene-styrene copolymer; less than 0.01% for maleic anhydride-grafted polyolefin elastomer; and less than 0.05% for polytetrafluoroethylene.

4. The preparation process of maleic anhydride-grafted POE-compatible modified high-temperature flame-retardant PC / ABS alloy resin according to claim 1, characterized in that, The precise feeding step S2 specifically includes: premixing dried high heat-resistant polycarbonate, heat-resistant acrylonitrile-butadiene-styrene copolymer, maleic anhydride grafted polyolefin elastomer, antioxidant 1076, antioxidant 168 and pentaerythritol stearate in a high-speed mixer for 5-10 minutes to form premix A; adding premix A to the main feed port of a co-rotating twin-screw extruder; pre-dispersing liquid bisphenol A bis(diphenyl phosphate) and polytetrafluoroethylene powder in a shear tank for 15-30 minutes, with the rotation speed of the shear tank controlled at 800-1200 rpm, to form a uniform suspension B, which is then added to the side feed port of the extruder.

5. The preparation process of maleic anhydride-grafted POE-compatible modified high-temperature flame-retardant PC / ABS alloy resin according to claim 1, characterized in that, The specific steps of step S3, melt blending extrusion, include: controlling the screw speed of the co-rotating twin-screw extruder at 400-600 rpm; setting the temperature of each heating zone of the extruder from the feed port to the die head as follows: Zone 1 feeding section: 200-220℃; Zones 2 to 4 melt plasticizing sections: 240-260℃; Zone 5 side feed port section: 230-250℃; Zones 6 to 7 reaction and dispersion sections: 260-280℃; Zone 8 vacuum exhaust. Section 1: 250-270℃; Homogenization and pressure building section 9 to 10: 240-260℃; Die head temperature: 250-270℃; Among them, the residence time of the material in the high temperature and strong shear reaction section of zone 6 to 7 is 15-25 seconds to ensure that the maleic anhydride groups and the end groups in the high heat-resistant polycarbonate and heat-resistant acrylonitrile-butadiene-styrene copolymer undergo sufficient interfacial reaction; Vacuum exhaust is set in zone 8, and the vacuum degree is not lower than -0.08MPa.

6. The preparation process of maleic anhydride-grafted POE-compatible modified high-temperature flame-retardant PC / ABS alloy resin according to claim 1, characterized in that, The steps S4, stretching, cooling, and pelletizing, specifically include: extruding the homogeneous melt into strips through a multi-hole template in the die head, cooling and shaping it in a cold water bath at a temperature of 50-70℃, removing surface moisture with a drying device, and then pelletizing it.

7. The preparation process of maleic anhydride-grafted POE-compatible modified high-temperature flame-retardant PC / ABS alloy resin according to claim 1, characterized in that, The post-processing and packaging of step S5 specifically includes: drying the cut granules at 80-100℃ for 2-4 hours to eliminate internal stress and further reduce the moisture content, and then screening, homogenizing and mixing them before vacuum packaging and warehousing.

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