Preparation process of maleic anhydride grafted POE compatible modified high-temperature-resistant flame-retardant PC / ABS alloy resin

Abstract

The invention relates to the technical field of flame-retardant high-molecular polymer materials, in particular to a preparation process of maleic anhydride grafted POE (Polyolefin Elastomer) compatible modified high-temperature-resistant flame-retardant PC / ABS (Polycarbonate / Acrylonitrile In the modification process of high heat resistance and halogen-free flame retardancy of PC / ABS alloy, the technical problem that the heat resistance, toughness and flame retardancy are difficult to synergistically improve is often caused. The invention adopts a collaborative optimization preparation process. A specific step-by-step charging melt blending extrusion strategy is adopted, PC and heat-resistant ABS are used as maleic anhydride grafted POE of a core compatilizer for melt mixing, after the PC and the heat-resistant ABS are fully plasticized and a stable phase structure is preliminarily formed, a heat-sensitive halogen-free phosphorus flame retardant and an anti-dripping agent are injected, premature decomposition and failure of the flame retardant at a high temperature are avoided, and the flame-retardant and anti-dripping composite material is prepared. The POE-g-MAH is introduced into the PC / ABS alloy resin, so that full reaction of the POE-g-MAH at the PC / ABS phase interface is ensured, the dispersed phase form is optimized, the low-temperature impact toughness and stress cracking resistance of the PC / ABS alloy resin are enhanced, and the problem of material brittleness caused by introduction of a flame retardant is solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of high molecular polymer materials, in particular to a preparation process of a maleic anhydride grafted POE compatibly modified high-temperature-resistant flame-retardant PC / ABS alloy resin. BACKGROUND

[0002] PC / ABS alloy, as an engineering plastic with excellent comprehensive performance, has become one of the platform materials in the modified plastic field because it naturally combines the excellent impact toughness, heat resistance and dimensional stability of polycarbonate (PC) and the good processing fluidity, rigidity and surface gloss of ABS resin. Based on its advantages in high toughness and processability, it has become an ideal choice for the fields of automotive interior and exterior parts, 5G communication equipment and high-end electronic and electrical equipment shells, etc. which require higher heat resistance and environmentally friendly halogen-free flame retardancy. In the prior art, phosphorus-based flame retardants (such as BDP) are usually added to achieve halogen-free flame retardation, and maleic anhydride grafted elastomers (such as POE-g-MAH) are introduced as compatibilizers to compensate for the loss of the ability to resist fracture when subjected to external impact due to the complexity of the blended system. Although these technical routes are theoretically feasible, there are still unresolved process contradictions in actual industrial production, especially in continuous melt blending extrusion processes.

[0003] In the melt blending process of industrialized continuous production of the above components, there is a technical problem of how to design an extrusion process that can provide sufficient energy and reaction time for the compatibilizer system which needs high temperature to occur effective chemical reaction in the same processing flow, while avoiding the premature decomposition of other functional additives (such as phosphorus-based flame retardants) in the system which are sensitive to heat and shear due to long time in the processing environment. The traditional one-step blending process often cannot reconcile this contradiction. High temperature and strong shear are beneficial to the compatibilization reaction, but they can easily lead to the degradation of the flame retardant, resulting in unstable flame retardant performance, appearance defects and even mechanical property reduction of the final product. If mild process conditions are used to protect the flame retardant, the interfacial compatibilization effect of the compatibilizer will be greatly reduced, and the toughness of the material cannot be effectively solved. Therefore, developing a new preparation process that can skillfully balance the different needs of different components in the processing process has become a key technical bottleneck for the stable production of high-performance PC / ABS alloy. SUMMARY

[0004] In view of the above existing problems, the present application is proposed.

[0005] Therefore, in order to solve the technical problems that PC / ABS alloy is difficult to synergistically achieve high heat resistance, high impact toughness and high-efficiency halogen-free flame retardancy in the prior art, the present application provides a preparation process of a maleic anhydride grafted POE compatibly modified high-temperature-resistant flame-retardant PC / ABS alloy resin.

[0006] To solve the above technical problems, the present application provides the following technical solutions: The application provides a preparation process of a maleic anhydride grafted POE compatible modified high-temperature-resistant flame-retardant PC / ABS alloy resin, which comprises the following steps and raw materials: high-temperature-resistant polycarbonate, high-temperature-resistant acrylonitrile-butadiene-styrene copolymer, maleic anhydride grafted polyolefin elastomer, bisphenol A bis(diphenyl phosphate), polytetrafluoroethylene, antioxidant 1076, antioxidant 168 and pentaerythritol stearate, characterized in that the process comprises the following steps: S1, drying treatment of raw materials: drying high-temperature-resistant polycarbonate, high-temperature-resistant acrylonitrile-butadiene-styrene copolymer resin, maleic anhydride grafted polyolefin elastomer, antioxidant 1076, antioxidant 168, polytetrafluoroethylene powder and pentaerythritol stearate; S2, accurate feeding: feeding the dried high-temperature-resistant polycarbonate particles, high-temperature-resistant acrylonitrile-butadiene-styrene copolymer particles, maleic anhydride grafted polyolefin elastomer toughening agent, antioxidant 1076, antioxidant 168 and pentaerythritol stearate into the main feeding port of an extruder, feeding bisphenol A bis(diphenyl phosphate) and polytetrafluoroethylene into the side feeding port to obtain polymer raw materials; S3, melt blending and extrusion: controlling a co-rotating twin-screw extruder to melt and shear mix the polymer raw materials, promoting micro-dispersion and interfacial compatibility of the components; performing vacuum exhaust on the formed melt to remove volatile substances; performing homogenization treatment on the melt and establishing a stable pressure for extrusion molding; S4, pulling, cooling and granulating: extruding the homogenized melt through the porous template of a die head for molding, then cooling and setting, and then drying and granulating; S5, post-treatment and packaging: screening and homogenizing the cut particles, and packing and storing the qualified particles.

[0007] As a preferred scheme of the preparation process of the maleic anhydride grafted POE compatible modified high-temperature-resistant flame-retardant PC / ABS alloy resin, the following raw materials are prepared by weight parts: high-temperature-resistant polycarbonate 50-75 parts; heat-resistant acrylonitrile-butadiene-styrene copolymer 15-35 parts; maleic anhydride grafted polyolefin elastomer 5-12 parts; bisphenol A bis(diphenyl phosphate) 10-18 parts; polytetrafluoroethylene 0.3-1.0 parts; the amount of antioxidant 1076 is 0.1-0.3 parts, the amount of antioxidant 168 is 0.2-0.5 parts; pentaerythritol stearate 0.5-1.5 parts; wherein, the specific weight parts of raw materials: high-temperature-resistant polycarbonate 65 parts; heat-resistant acrylonitrile-butadiene-styrene copolymer 25 parts; maleic anhydride grafted polyolefin elastomer 8 parts; bisphenol A bis(diphenyl phosphate) 15 parts; polytetrafluoroethylene 0.5 parts; antioxidant 1076 is 0.17 parts, antioxidant 168 is 0.33 parts; pentaerythritol stearate 1.0 parts.

[0008] As a preferred scheme of the preparation process of the maleic anhydride grafted POE compatible modified high-temperature-resistant flame-retardant PC / ABS alloy resin, the melt index (300℃, 1.2kg) of the high-temperature-resistant polycarbonate is 5-15g / 10min, and the softening point is not less than 145℃; the Vicat softening point of the heat-resistant ABS resin is not less than 105℃; the grafting rate of maleic anhydride in the maleic anhydride grafted polyolefin elastomer is between 0.8-1.5wt%.

[0009] As a preferred scheme of the preparation process of the maleic anhydride grafted POE compatible modified high-temperature-resistant flame-retardant PC / ABS alloy resin, wherein: the high-temperature-resistant polycarbonate, heat-resistant acrylonitrile-butadiene-styrene copolymer resin, maleic anhydride grafted polyolefin elastomer, antioxidant 1076, antioxidant 168, polytetrafluoroethylene powder and pentaerythritol stearate are subjected to drying treatment, and the specific steps are as follows: After drying treatment, the water content of each raw material is: high-temperature-resistant polycarbonate is less than 0.02%; heat-resistant acrylonitrile-butadiene-styrene copolymer is less than 0.01%; maleic anhydride grafted polyolefin elastomer is less than 0.01%; polytetrafluoroethylene is less than 0.05%.

[0010] As a preferred scheme of the preparation process of the maleic anhydride grafted POE compatible modified high-temperature-resistant flame-retardant PC / ABS alloy resin, wherein: the dried high-temperature-resistant polycarbonate particles, heat-resistant acrylonitrile-butadiene-styrene copolymer particles, maleic anhydride grafted polyolefin elastomer toughener, antioxidant 1076, antioxidant 168 and pentaerythritol stearate are added to the main feeding port of the extruder, and bisphenol A bis(diphenyl phosphate) and polytetrafluoroethylene are added to the side feeding port to obtain polymer raw materials, and the specific steps are as follows: The dry high-heat-resistant polycarbonate, heat-resistant ABS resin, maleic anhydride grafted polyolefin elastomer, antioxidant 1076, antioxidant 168 and pentaerythritol stearate are pre-mixed in a high-speed mixer for 5-10 minutes to form a pre-mixed material A; the pre-mixed material A is added to the main feeding port of the co-rotating twin-screw extruder; the liquid bisphenol A bis(diphenyl phosphate) and polytetramethylene ether glycol powder are pre-sheared and dispersed in a shearing tank for 15-30 minutes, the rotating speed of the shearing tank is controlled at 800-1200 rpm, and a uniform suspension B is formed and added to the side feeding port of the extruder.

[0011] As a preferred scheme of the preparation process of the maleic anhydride grafted POE compatibly modified high-heat-resistant flame-retardant PC / ABS alloy resin, in the co-rotating twin-screw extruder, the screw rotating speed is controlled at 400-600 rpm; from the self-feeding port to the die head of the extruder, the temperature of each heating zone is set as follows: zone 1 (feeding section): 200-220℃; zones 2-4 (melting and plasticizing section): 240-260℃; zone 5 (side feeding port section): 230-250℃; zones 6-7 (reaction and dispersion section): 260-280℃; zone 8 (vacuum exhaust section): 250-270℃; zones 9-10 (homogenization and pressure building section): 240-260℃; die head temperature: 250-270℃; wherein, the residence time of the material in the high-temperature and strong-shearing reaction section of zones 6-7 is 15-25 seconds, ensuring that the maleic anhydride groups fully react with the end groups in PC and ABS; vacuum exhaust is set in zone 8, and the vacuum degree is not less than -0.08 MPa.

[0012] As a preferred scheme of the preparation process of the maleic anhydride grafted POE compatibly modified high-heat-resistant flame-retardant PC / ABS alloy resin, in the co-rotating twin-screw extruder, the screw rotating speed is controlled at 400-600 rpm; from the self-feeding port to the die head of the extruder, the temperature of each heating zone is set as follows: zone 1 (feeding section): 200-220℃; zones 2-4 (melting and plasticizing section): 240-260℃; zone 5 (side feeding port section): 230-250℃; zones 6-7 (reaction and dispersion section): 260-280℃; zone 8 (vacuum exhaust section): 250-270℃; zones 9-10 (homogenization and pressure building section): 240-260℃; die head temperature: 250-270℃; wherein, the residence time of the material in the high-temperature and strong-shearing reaction section of zones 6-7 is 15-25 seconds, ensuring that the maleic anhydride groups fully react with the end groups in PC and ABS; vacuum exhaust is set in zone 8, and the vacuum degree is not less than -0.08 MPa.

[0013] As a preferred scheme of the preparation process of the maleic anhydride grafted POE compatibly modified high-heat-resistant flame-retardant PC / ABS alloy resin, in the co-rotating twin-screw extruder, the screw rotating speed is controlled at 400-600 rpm; from the self-feeding port to the die head of the extruder, the temperature of each heating zone is set as follows: zone 1 (feeding section): 200-220℃; zones 2-4 (melting and plasticizing section): 240-260℃; zone 5 (side feeding port section): 230-250℃; zones 6-7 (reaction and dispersion section): 260-280℃; zone 8 (vacuum exhaust section): 250-270℃; zones 9-10 (homogenization and pressure building section): 240-260℃; die head temperature: 250-270℃; wherein, the residence time of the material in the high-temperature and strong-shearing reaction section of zones 6-7 is 15-25 seconds, ensuring that the maleic anhydride groups fully react with the end groups in PC and ABS; vacuum exhaust is set in zone 8, and the vacuum degree is not less than -0.08 MPa.

[0014] As a preferred scheme of the preparation process of the maleic anhydride grafted POE compatible modified high-temperature-resistant flame-retardant PC / ABS alloy resin, the post-processing and packaging specifically comprises: post-drying the cut particles at 80-100 DEG C for 2-4 hours to eliminate internal stress and further reduce the water content, and then screening, homogenizing and mixing, and then vacuum packaging and warehousing.

[0015] The present application has the following advantages: The stepwise feeding strategy adopted in the present application first mixes PC, ABS and the compatilizer in a high-temperature environment, and then adds the heat-sensitive flame retardant in a relatively mild environment for mixing, thereby providing respective "optimal processing windows" for materials with different requirements, ensuring that the compatilizer can fully react with PC / ABS at high temperature to strengthen the interfacial bonding force, thereby solving the brittleness problem of the material; by injecting the flame retardant into the formed melt, the thermal decomposition of the flame retardant under processing conditions is effectively avoided, thereby ensuring the stable flame-retardant performance and excellent heat resistance of the final product. Therefore, the present application solves the technical contradiction that toughness, heat resistance and flame retardance are difficult to be considered simultaneously in the modification process of PC / ABS alloy from the process aspect. BRIEF DESCRIPTION OF DRAWINGS In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed in the embodiment description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor. Figure 1 The preparation flow chart of the alloy resin of the present application. DETAILED DESCRIPTION

[0016] In order to make the above-mentioned purposes, features and advantages of the present application more apparent and easy to understand, the specific embodiments of the present application will be described in detail below with reference to the drawings.

[0017] In the following description, many specific details are set forth in order to provide a thorough understanding of the present application, but the present application can also be implemented in other ways different from those described herein, and those skilled in the art can make similar generalizations without departing from the connotation of the present application, therefore the present application is not limited to the specific embodiments disclosed below.

[0018] Secondly, the term "one embodiment" or "embodiments" herein refers to a specific feature, structure or property that can be included in at least one implementation of the present application. The term "in one embodiment" appearing in different places in the specification does not refer to the same embodiment, nor is it an embodiment that is separate or alternative to other embodiments.

[0019] The following examples of the present application and comparative examples of maleic anhydride grafted POE compatible modified high temperature resistant flame retardant PC / ABS alloy resin preparation method, as shown below:

[0020] Reference Figure 1 For an embodiment of the present application, the present embodiment provides a preparation process of maleic anhydride grafted POE compatible modified high temperature resistant flame retardant PC / ABS alloy resin, and the preparation method comprises the following steps: Step one, raw material preparation: the following raw materials are weighed according to the weight parts: high heat resistant grade polycarbonate (PC) 65 parts; heat resistant grade acrylonitrile-butadiene-styrene copolymer (ABS) 25 parts; maleic anhydride grafted polyolefin elastomer (POE-g-MAH) 8 parts; bisphenol A bis (diphenyl phosphate) (BDP) 15 parts; polytetrafluoroethylene (PTFE) 0.5 parts; antioxidant 1076 is 0.17 parts, antioxidant 168 is 0.33 parts; pentaerythritol stearate 1.0 parts. Among them, the Vicat softening point of high heat resistant grade polycarbonate is 148℃; the Vicat softening point of heat resistant grade ABS resin is 107℃; the grafting rate of maleic anhydride in maleic anhydride grafted polyolefin elastomer is 1.0wt%.

[0021] Step two, raw material treatment and feeding: the high heat resistant grade polycarbonate is dried at 125℃ for 5 hours; the heat resistant grade ABS resin and the maleic anhydride grafted polyolefin elastomer are dried at 85℃ for 4 hours. After drying, the polycarbonate, ABS, maleic anhydride grafted polyolefin elastomer and powdered antioxidants, pentaerythritol stearate are mixed together in a high-speed mixer for 5 minutes, and then added to the main feeding port of the co-rotating twin screw extruder through the weight loss feeder. The liquid bisphenol A bis (diphenyl phosphate) and polytetrafluoroethylene powder are pre-sheared in a shearing tank at 1000 rpm for 20 minutes to form a suspension, and then added to the side feeding port of the extruder through a metering pump.

[0022] Step three, melt blending extrusion: control the screw speed of the co-rotating twin screw extruder (length-diameter ratio L / D=40) at 450 rpm, and set the temperature of each zone as follows: zone one 220℃, zones two to four 250℃, zone five 240℃, zones six to seven (reaction and dispersion section) 275℃, zone eight 265℃, zones nine to ten 255℃, and die head 260℃. The material completes melting, dispersion and interfacial compatibility reaction under high temperature and strong shear, and removes volatile matter through a vacuum degassing section with a vacuum degree of-0.08MPa.

[0023] Step four, post-treatment: the extruded strip is cooled in a 60℃ water tank, blown dry and then pelletized. The obtained particles are post-dried at 90℃ for 3 hours, After detection, the alloy resin particles prepared in the present embodiment are uniform and milky white, and the surface is smooth. The Izod notched impact strength (-30℃) is , and the heat distortion temperature was 118℃, and the sample passed the UL94 V-0 level combustion test. The sample was used as a benchmark to evaluate the comprehensive performance of subsequent examples and comparative examples.

[0024] A preparation method of a maleic anhydride grafted POE compatible modified high-temperature-resistant flame-retardant PC / ABS alloy resin, which comprises the following steps: Step one, raw material preparation: the following raw materials are weighed according to weight parts: high-temperature-resistant polycarbonate 55 parts; heat-resistant acrylonitrile-butadiene-styrene copolymer 35 parts; maleic anhydride grafted polyolefin elastomer 12 parts; bisphenol A bis (diphenyl phosphate) 12 parts; polytetrafluoroethylene 0.5 parts; 0.5 parts of antioxidant 1076 and antioxidant 168; pentaerythritol stearate 1.0 part. Among them, the key parameters of each raw material are the same as in example 1, and the remaining step conditions are the same as in example 1.

[0025] It is detected that, by increasing the content of ABS and POE-g-MAH, the possibility of higher toughness is explored. The cantilever beam notched impact strength (-30℃) of the obtained alloy resin is increased to , which shows more excellent toughness, but the heat distortion temperature is slightly decreased to 115℃, and the sample still passes the UL94 V-0 level combustion test.

[0026] A preparation method of a maleic anhydride grafted POE compatible modified high-temperature-resistant flame-retardant PC / ABS alloy resin, which comprises the following steps: Step one, raw material preparation: the following raw materials are weighed according to weight parts: high-temperature-resistant polycarbonate 55 parts; heat-resistant acrylonitrile-butadiene-styrene copolymer 35 parts; maleic anhydride grafted polyolefin elastomer 12 parts; bisphenol A bis (diphenyl phosphate) 12 parts; polytetrafluoroethylene 0.5 parts; 0.5 parts of antioxidant 1076 and antioxidant 168; pentaerythritol stearate 1.0 part. Among them, the key parameters of each raw material are the same as in example 1, and the remaining step conditions are the same as in example 1.

[0027] It is detected that, by increasing the content of PC, the possibility of higher heat resistance is explored. The heat distortion temperature of the obtained alloy resin is increased to 122℃, and the heat resistance is extremely prominent, and the cantilever beam notched impact strength (-30℃) is , which still maintains a good toughness level, and passes the UL94 V-0 level combustion test.

[0028] A preparation method of a PC / ABS alloy resin, which comprises the following steps: The preparation method is basically the same as that of example 1, and the difference lies in that the grafting rate of maleic anhydride in the maleic anhydride grafted polyolefin elastomer in the raw material ratio of step one is only 0.3wt%. All the remaining conditions are the same as in example 1.

[0029] It is detected that the compatibility effect is very poor due to the too low grafting rate (0.3wt%) of the maleic anhydride grafted polyolefin elastomer, and the notched Charpy impact strength of the obtained alloy resin at -30℃ is only The injection molded sample is broken in the impact test, and shows the brittle fracture characteristics.

[0030] A PC / ABS alloy resin is prepared by the following steps: The preparation method is basically the same as that of Example 1, except that the grafting rate of the maleic anhydride in the maleic anhydride grafted polyolefin elastomer used in step one is increased to 2.5wt%. All the other raw materials, proportions and process parameters remain the same as those of Example 1.

[0031] It is detected that the slight crosslinking of POE-g-MAH itself occurs due to the too high grafting rate (2.5wt%) of the maleic anhydride, and the dispersibility is poor. Meanwhile, the excessive active points can also cause the side reaction of PC. The low temperature impact toughness of the final product is obviously decreased , and the melt index of the material is reduced, and the processing fluidity is poor.

[0032] A PC / ABS alloy resin is prepared by the following steps: The preparation method is basically the same as that of Example 1, except that in step three, the melt blending extrusion: the screw speed of the co-rotating twin-screw extruder (length-diameter ratio L / D=40) is controlled to be 450rpm, and the temperature of each zone is set to be: zone one 220℃, zones two to four 250℃, zone five 240℃, zones six to seven 240℃, zone eight 235℃, zones nine to ten 230℃, and the die 235℃. The material is melted and dispersed under shearing, and the volatile matter is removed through the vacuum degassing section with a vacuum degree of -0.08MPa.

[0033] It is detected that the interface reaction is insufficient due to the insufficient temperature (240℃) of the reaction section, and the notched Charpy impact strength of the obtained alloy resin at -30℃ is greatly decreased to , which also shows obvious brittleness.

[0034] A PC / ABS alloy resin is prepared by the same method as that of Example 1, except that in the raw material preparation of step one: the same raw materials as those of Example 1 are weighed by weight parts, and the grafting rate of POE-g-MAH is also 1.0wt%. The raw materials used are ordinary polycarbonate (Vicat softening point 142℃) and ordinary ABS resin (Vicat softening point 94℃), and the ordinary polycarbonate is dried at 120℃ for 5 hours, and the ordinary ABS resin and the maleic anhydride grafted polyolefin elastomer are dried at 80℃ for 4 hours in the raw material treatment and feeding of step two. The rest of the feeding operation and step conditions remain the same as those of Example 1.

[0035] The detection shows that the heat distortion temperature of the obtained alloy resin is only 101℃, far lower than the high temperature resistance requirement of the present application, although the impact performance is acceptable.

[0036] A PC / ABS alloy resin is prepared by the same method as in Example 1, with the only difference being that the amount of high heat-resistant polycarbonate in the raw material ratio in Step 1 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 consistent with those in Example 1.

[0037] The detection shows that due to the excessive amount of BDP (22 parts) resulting in strong plasticizing effect, the heat distortion temperature (HDT) of the obtained alloy resin is significantly reduced from 118℃ in Example 1 to 108℃, which cannot meet the high heat resistance requirement.

[0038] A PC / ABS alloy resin is prepared by the same method as in Example 1, with the only difference being that the amount of high heat-resistant polycarbonate in the raw material ratio in Step 1 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 consistent with those in Example 1.

[0039] The detection shows that due to the insufficient amount of BDP (8 parts), the obtained alloy resin cannot pass the V-0 level in the vertical burning test, and can only reach the V-1 level, failing to achieve the goal of high-efficiency flame retardation.

[0040] A PC / ABS alloy resin is prepared by the same method as in Example 1, with the only difference being that the amount of high heat-resistant polycarbonate in the raw material ratio in Step 1 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 consistent with those in Example 1.

[0041] The detection shows that due to the insufficient amount of compatibilizer (3 parts), an effective interface network cannot be formed, and the cantilever beam notched impact strength of the obtained alloy resin at -30℃ is sharply reduced to , and the burning level is reduced to V-2, indicating that the compatibility also has an impact on the stability of the flame retardation system.

[0042] A PC / ABS alloy resin is prepared by the same method as in Example 1, with the only difference being that the amount of high heat-resistant polycarbonate in the raw material ratio in Step 1 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 consistent with those in Example 1.

[0043] It was found that the 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 obtained alloy resin, and its heat distortion temperature (HDT) dropped to 105°C.

[0044] A PC / ABS alloy resin was prepared by substantially the same method as in Example 1, except that the screw rotation speed in the melt blending extrusion process of Step 3 was increased to 700 rpm. All other conditions were kept the same as in Example 1.

[0045] It was observed during the extrusion process that the excessively high rotation speed of 700 rpm resulted in a rough surface of the melt strip, with a "shark skin" phenomenon. It was found that the excessive shear heat had caused polymer degradation, resulting in a decrease in the heat distortion temperature of the obtained alloy resin to 110°C, and a significant decrease in the low-temperature impact toughness.

[0046] A PC / ABS alloy resin was prepared by substantially the same method as in Example 1, except that the screw rotation speed in the melt blending extrusion process of Step 3 was decreased to 200 rpm.

[0047] It was found that the excessively low rotation speed of 200 rpm provided insufficient shear force, resulting in uneven dispersion of the components, especially PTFE. Although the mechanical properties of the final product were acceptable, it failed the vertical burning test due to the inability of PTFE to form an effective network, and the flame retardant rating was reduced to V-2.

[0048] A PC / ABS alloy resin was prepared by substantially the same method as in Example 1, except that the feeding method in Step 2 was changed: all the dried raw materials, including PC, ABS, POE-g-MAH, BDP, PTFE, and all additives, were pre-mixed in a high-speed mixer for 5 minutes, and then fed into the extruder together from the main feeding port. All other conditions, including raw material ratios and extrusion process parameters, were kept the same as in Example 1.

[0049] This comparative example was intended to simulate the traditional "one-step" process. It was observed during the extrusion process that the melt color slightly darkened. It was found that due to the premature thermal decomposition of the heat-sensitive BDP and interference with the compatibilization reaction, the heat distortion temperature of the obtained alloy resin decreased to 112°C, and the low-temperature impact toughness was also significantly lower than that of Example 1. .

[0050] A PC / ABS alloy resin was prepared by substantially the same method as in Example 1, except that no polytetrafluoroethylene (PTFE) was added in the raw material preparation of Step 1. The amounts of all other components and the preparation conditions were kept the same as in Example 1.

[0051] It is detected that, although the material has good mechanical and thermal properties, the sample melts and drips and ignites the underlying cotton wool in the vertical burning test, so that the combustion rating can only be rated as V-2.

[0052] Performance detection: The alloy resin particles prepared in Examples 1-3 and Comparative Examples 1-12 are injection molded into standard samples by an injection molding machine, and the performance tests are carried out according to the standard, and the comprehensive results are shown in the following table.

[0053] Izod notched impact strength: tested according to ASTM D256 standard; (2) Heat distortion temperature (HDT): tested according to ASTM D648 standard (1.8 MPa load); (3) Vertical combustion rating: tested according to UL94 standard (1.6 mm thickness), V-0 rating is higher than V-2 rating, and the flame retardant performance is better, and the combustion degree is lighter.

[0054]

[0055] Comprehensive analysis and determination of the final preferred scheme: Through the above series of examples and comparative example experiments, the present application now comprehensively analyzes and weighs all experimental results, and finally determines the preferred technical scheme of the present application.

[0056] I. Comprehensive analysis The core of the present application is to solve the performance balance problem between high heat resistance, high toughness and high efficiency halogen-free flame retardant by selecting specific raw materials, ratio range and innovative step-by-step feeding process.

[0057] 1. Analysis of synergistic effect of raw material selection and ratio: Main resin (comparative example 4): the results show that using high heat-resistant PC (Vicat softening point not less than 145℃) and heat-resistant ABS (Vicat softening point not less than 105℃) is the necessary prerequisite to realize high heat distortion temperature (HDT> 110℃) of the final product.

[0058] Compatibilizer POE-g-MAH (comparative examples 1, 2, 7, 8): data confirms that the grafting rate of maleic anhydride is between 0.8-1.5wt%, and the amount is in the range of 5-12 parts by weight, which is the best technical window to build strong and tough interface phase, realize excellent low temperature impact toughness Without sacrificing the rigidity and heat resistance of the material.

[0059] Flame retardant system (comparative examples 5, 6, 12): the amount of BDP in 10-18 parts by weight is the key to achieve UL94 V-0 level flame retardant and avoid excessive plasticization leading to HDT decrease; while the addition of PTFE is necessary to prevent burning dripping and pass V-0 level test.

[0060] Ratio balance (examples 1-3): the results of examples 1-3 clearly show that by adjusting the PC / ABS ratio, high heat resistance (such as example 3, HDT up to 122℃) and ultra-high toughness (such as example 2, impact strength at -30℃ up to 30kJ / m2) can be controlled, while example 1 represents the best balance point of the two.

[0061] 2. Analysis of the decisive role of the preparation process: Stepwise feeding process (comparative example 11): comparative example 11 uses the traditional "one-step" blending, even if the raw material formula is exactly the same as example 1, its low-temperature impact toughness is far inferior to that of example 1 . This proves that the "main resin and compatibilizer are first melted, and the heat-sensitive flame retardant is then injected" stepwise feeding strategy adopted in the present application is the core technology to avoid degradation of the flame retardant and ensure sufficient compatibilization reaction, and is the decisive factor to achieve the final high performance.

[0062] Process parameters (comparative examples 3, 9, 10): the results show that the reaction dispersion section temperature 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.

[0063] II. Determination of preferred schemes Based on the above analysis, a preferred technical scheme of the present application is as follows: 1. Preferred formula (in parts by weight): High heat-resistant polycarbonate 65 parts; heat-resistant acrylonitrile-butadiene-styrene copolymer 25 parts; maleic anhydride grafted polyolefin elastomer with a grafting rate of about 1.0wt% 8 parts; bisphenol A-bis(diphenyl phosphate) 15 parts; polytetrafluoroethylene 0.5 parts; antioxidant 1076 and antioxidant 168 together 0.5 parts; pentaerythritol stearate 1.0 part.

[0064] 2. Preferred process flow: ​The stepwise feeding co-rotating twin-screw extrusion process is adopted. The dried PC, ABS, POE-g-MAH and solid additives are added from the main feeding port; the suspension of BDP and PTFE pre-dispersed is injected from the side feeding port in the middle section of the cylinder. The temperature of the extruder reaction dispersion section is controlled at 270-275 DEG C, the screw rotation speed is controlled at about 450 rpm, and the vacuum exhaust of no less than -0.08 MPa is set. The extruded material is water-cooled, granulated, and then subjected to post-drying treatment at 90-100 DEG C.

[0065] The alloy resin prepared in the preferred scheme (i.e. Example 1) achieves a comprehensive balance among the heat distortion temperature (118 DEG C), low-temperature impact toughness and halogen-free flame retardancy (UL94 V-0 grade), embodies the technical concept and beneficial effects of the present application, and is the best implementation mode for realizing stable and efficient industrialized production of the high-performance alloy resin.

[0066] In summary, the stepwise feeding strategy adopted in the present application provides respective "optimal processing windows" for materials with different requirements by first mixing PC, ABS and the compatibilizer in a high-temperature environment and then adding the heat-sensitive flame retardant in a relatively mild environment for mixing, ensures that the compatibilizer can fully react with PC / ABS at high temperature to strengthen the interfacial bonding force, and solves the brittleness problem of the material; by injecting the flame retardant into the formed melt, the thermal decomposition of the flame retardant under processing conditions is effectively avoided, and the stable flame retardant performance and excellent heat resistance of the final product are ensured. Therefore, the present application solves the technical contradiction that toughness, heat resistance and flame retardancy are difficult to be considered simultaneously in the modification process of PC / ABS alloy from the process aspect.

[0067] It should be noted that the above examples are only used to illustrate the technical solutions of the present application and not to limit it. Although the present application has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that the technical solutions of the present application can be modified or replaced equivalently without departing from the spirit and scope of the technical solutions of the present application, and they should be covered in the scope of the claims of the present application.

Claims

1. A preparation process of a maleic anhydride grafted POE compatible modified high-temperature-resistant flame-retardant PC / ABS alloy resin, raw materials comprising the following components: high-temperature-resistant polycarbonate, high-temperature-resistant acrylonitrile-butadiene-styrene copolymer, maleic anhydride grafted polyolefin elastomer, bisphenol A bis(diphenyl phosphate), polytetrafluoroethylene, antioxidant 1076, antioxidant 168, pentaerythritol stearate, characterized in that, It comprises the following steps: S1 raw material drying treatment: high heat-resistant grade polycarbonate, heat-resistant grade acrylonitrile-butadiene-styrene copolymer resin, maleic anhydride grafted polyolefin elastomer, antioxidant 1076, antioxidant 168, polytetrafluoroethylene powder and pentaerythritol stearate are subjected to drying treatment; S2 precise feeding: the dried high heat-resistant grade polycarbonate particles, heat-resistant grade acrylonitrile-butadiene-styrene copolymer particles, maleic anhydride grafted polyolefin elastomer toughening agent, antioxidant 1076, antioxidant 168 and pentaerythritol stearate are added to the main feeding port of the extruder, and bisphenol A bis(diphenyl phosphate) and polytetrafluoroethylene are added to the side feeding port to obtain polymer raw materials; S3 melt blending and extrusion: control the co-rotating twin screw extruder to melt and shear mix the polymer raw materials, promote the micro-dispersion and interfacial compatibility of each component; the formed melt is subjected to vacuum exhaust to remove volatile substances; the melt is subjected to homogenization treatment and stable pressure is established for extrusion molding; S4 stretching, cooling and granulation: the homogenized melt is extruded into a shape through the multi-hole template of the die head, and after cooling and setting, it is dried and then granulated; S5 post-treatment and packaging: the cut particles are screened and homogenized, and the qualified particles 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, Prepare the following raw materials by weight parts: high heat-resistant grade polycarbonate 50-75 parts; heat-resistant grade ABS resin 15-35 parts; maleic anhydride grafted polyolefin elastomer 5-12 parts; bisphenol A bis(diphenyl phosphate) 10-18 parts; polytetrafluoroethylene 0.3-1.0 parts; the amount of antioxidant 1076 is 0.1-0.3 parts, the amount of antioxidant 168 is 0.2-0.5 parts; pentaerythritol stearate 0.5-1.5 parts.

3. 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, Specific weight parts of raw materials: high heat-resistant grade polycarbonate 65 parts; heat-resistant grade acrylonitrile-butadiene-styrene copolymer 25 parts; maleic anhydride grafted polyolefin elastomer 8 parts; bisphenol A bis(diphenyl phosphate) 15 parts; polytetrafluoroethylene 0.5 parts; antioxidant 1076 is 0.17 parts, antioxidant 168 is 0.33 parts; Pentaerythritol stearate 1.0 parts.

4. 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 melt index (300℃, 1.2kg) of the high heat-resistant grade polycarbonate is 5-15g / 10min, and the Vicat softening point is not less than 145℃; the Vicat softening point of the heat-resistant grade ABS resin is not less than 105℃; the grafting rate of maleic anhydride in the maleic anhydride grafted polyolefin elastomer is between 0.8-1.5wt%.

5. 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 raw material drying treatment of step S1 specifically includes: after drying treatment, the water content of each raw material is less than 0.02% for high heat-resistant grade polycarbonate; less than 0.01% for heat-resistant grade acrylonitrile-butadiene-styrene copolymer; less than 0.01% for maleic anhydride grafted polyolefin elastomer; and less than 0.05% for polytetrafluoroethylene.

6. 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 step S2 precisely feeding specifically includes: pre-mixing the 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 a pre-mixed material A; adding the pre-mixed material A into a main feeding port of a co-rotating twin-screw extruder; pre-shearing and dispersing liquid bisphenol A bis(diphenyl phosphate) and polytetrafluoroethylene powder in a shearing tank for 15-30 minutes, the shearing tank is controlled at a rotation speed of 800-1200 rpm to form a uniform suspension B, and adding the suspension B into a side feeding port of the extruder.

7. 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 step S3 melt blending and extruding specifically includes: controlling the screw rotation speed of the co-rotating twin-screw extruder at 400-600 rpm; setting the temperature of each heating zone from the feeding port to the die head of the extruder as follows: zone 1 (feeding section): 200-220℃; zones 2-4 (melt plasticizing section): 240-260℃; zone 5 (side feeding port section): 230-250℃; zones 6-7 (reaction and dispersion section): 260-280℃; zone 8 (vacuum exhaust section): 250-270℃; zones 9-10 (homogenization and pressure building section): 240-260℃; die head temperature: 250-270℃; wherein, the residence time of the material in the high-temperature and strong-shearing reaction section of zones 6-7 is 15-25 seconds, so as to ensure that the maleic anhydride groups fully react with the end groups in the high-heat-resistant polycarbonate and the heat-resistant acrylonitrile-butadiene-styrene copolymer; setting a vacuum exhaust in zone 8, and the vacuum degree is not less than -0.08 MPa.

8. The process for preparing a maleic anhydride grafted POE compatibilized modified high temperature resistant flame retardant PC / ABS alloy resin according to claim 7, characterized in that, In zone 1, the main solid raw materials such as PC and ABS are first fed and preheated to prepare for subsequent melting, reaction and side-port addition of additives; in zone 5, after the PC / ABS melt is formed, the heat-sensitive flame retardant is injected, which can protect the flame retardant from decomposition and ensure the best reaction effect of the compatibilizer; in zone 8, after the melt is fully reacted, volatile substances such as moisture, air and reaction by-products are removed before extrusion molding, so as to ensure that the final product is free of bubbles and defects.

9. 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 step S4 stretching, cooling and pelletizing specifically includes: extruding the homogeneous melt through the perforated die plate of the die head into a strip shape, cooling and shaping in a cold water tank with water temperature of 50-70℃, removing surface moisture through a blow-drying device, and then pelletizing.

10. 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 step S5 post-treatment and packaging specifically includes: drying the cut particles at 80-100℃ for 2-4 hours to eliminate internal stress and further reduce the moisture content, and then screening, homogenizing and mixing, and then vacuum packaging and warehousing.

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