Anti-stress anti-coating bottom-biting PC / ABS (polycarbonate / acrylonitrile butadiene styrene) composite material and preparation method thereof

Abstract

The invention discloses a stress-resistant and coating-bottom-biting-resistant PC / ABS composite material and a preparation method thereof, and relates to the technical field of engineering plastic alloys. The invention relates to a stress-resistant and coating-bottom-biting-resistant PC / ABS (polycarbonate / acrylonitrile butadiene styrene) composite material, which comprises the following raw material components in parts by weight: 60-65 parts of polycarbonate; 20 to 25 parts of modified ABS resin; 5 to 8 parts of a core-shell methyl methacrylate-butadiene-styrene polymer; 3-5 parts of fluorinated nano silicon dioxide; 0.5 to 1 part of a fluorinated carbon nanotube; 8-10 parts of a phosphorus-nitrogen synergistic flame retardant; 0.3 to 0.5 part of phenyl zinc phosphate; 0.3 to 0.5 part of bismaleimide; and 0.5 to 1 part of a silane coupling agent KH550. Through functional complementation and interface synergy, all the components give consideration to stress resistance, coating bite resistance, freezing and thawing resistance, flame retardance, mechanical strength and environmental adaptability, and a reliable solution is provided for high-end engineering plastics in the fields of automobiles, electronics and the like.

Description

Technical Field

[0001] The invention relates to the technical field of engineering plastic alloys, in particular to a stress-resistant and coating-resistant PC / ABS composite material and a preparation method thereof. Background Art

[0002] The alloy material (PC / ABS) of polycarbonate (PC) and acrylonitrile-butadiene-styrene copolymer (ABS) is widely used in the fields of automobiles, electronics and consumer products due to its comprehensive performance advantages. The high strength and heat resistance of PC complement the processability and impact resistance of ABS, but the lack of compatibility between the two can easily lead to phase separation and weak interface bonding, which can easily lead to problems such as mechanical property degradation and poor dimensional stability during long-term use. Traditional modification methods mostly optimize the interface by adding compatibilizers or toughening agents, but it is still difficult to balance the requirements of environmental stress resistance, flame retardancy and surface functionalization, especially in high temperature, high humidity or coating processes, which can easily lead to defects such as coating peeling, swelling and cracking.

[0003] In the existing technology, flame retardant modification and anti-penetration design often rely on a single functional component. For example, halogen flame retardants are highly efficient but have poor environmental protection, and inorganic fillers can improve thermal stability but aggravate interface defects. In addition, conventional hydrophobic treatments mostly use physical coatings, which have shortcomings such as insufficient adhesion and poor durability, and are difficult to cope with microcrack propagation caused by freeze-thaw cycles or solvent erosion. The frequent occurrence of coating biting further limits the application of materials in high-end scenarios. How to achieve the coordinated improvement of flame retardancy, anti-penetration, mechanical strength and interface stability through material system innovation has become a technical difficulty that the industry urgently needs to break through. Summary of the invention

[0004] The object of the present invention is to provide a stress-resistant and anti-painting bottom biting PC / ABS composite material and a preparation method thereof, so as to solve the problems raised in the background technology.

[0005] To achieve the above object, the present invention provides the following technical solutions: A stress-resistant and coating-resistant PC / ABS composite material comprises the following raw material components by weight: Polycarbonate 60-65 parts; Modified ABS resin 20-25 parts; 5-8 parts of core-shell methyl methacrylate-butadiene-styrene polymer; 3-5 parts of fluorinated nano silicon dioxide; 0.5-1 part of fluorinated carbon nanotubes; 8-10 parts of phosphorus-nitrogen synergistic flame retardant; 0.3-0.5 part of phenyl zinc phosphate; 0.3-0.5 parts of bismaleimide; Silane coupling agent KH550 0.5-1 part; Furthermore, the preparation of the modified ABS resin is to modify the acrylonitrile-butadiene-styrene block copolymer, and the specific steps are as follows: A1. Treat acrylonitrile-butadiene-styrene block copolymer with ozone oxidation at an ozone concentration of 50-100 ppm and a temperature of 25-40° C. for 1-3 h, transfer to water at a temperature of 40-60° C. and a pH of 7-9 for hydrolysis for 0.5-2 h, rinse with deionized water, and dry to obtain ABS particles; A2, prepare sodium dodecyl sulfonate solution, add styrene, diisocyanate and glycidyl methacrylate into the sodium dodecyl sulfonate solution and mix, stir and react at 25°C at a speed of 500r / min for 10-15min, transfer the mixture to a high-pressure homogenizer, circulate emulsification 3 times at a pressure of 60MPa, stand at 25°C for 30min, adjust the pH value to 6.5-7, and obtain a monomer pre-emulsion; Furthermore, the mass ratio of the sodium dodecyl sulfonate solution, styrene, diisocyanate and glycidyl methacrylate is (270-310):(40-50):(13.5-16.5):(9-11); the sodium dodecyl sulfonate solution is prepared from sodium dodecyl sulfonate and deionized water, and the mass ratio of the sodium dodecyl sulfonate to deionized water is 1:(100-150); A3. Add ABS particles into a reactor under a nitrogen atmosphere, raise the temperature to 75° C., dropwise add part of the monomer pre-emulsion prepared in step A2 and part of the potassium persulfate solution at a rate of 0.5 mL / min, and stir at a speed of 200 r / min for 40-80 min to obtain a seed polymerization solution; Furthermore, the mass ratio of the ABS particles, the monomer pre-emulsion and the potassium persulfate solution is (135-140):(4-5):1; the potassium persulfate solution is prepared from potassium persulfate and deionized water, and the mass ratio of potassium persulfate to deionized water is 1:(9-11).

[0006] A4. Heat the reactor to 80°C, add the remaining monomer pre-emulsion and the remaining potassium persulfate solution in 3-4 batches at a stirring speed of 150 r / min, with an interval of 30 minutes between each batch. After all the pre-emulsion is added, continue stirring and reacting for 3-4 hours to obtain an emulsion; Furthermore, the potassium persulfate solution is prepared from potassium persulfate and deionized water, and the mass ratio of potassium persulfate to deionized water is 3:(6-8); the mass ratio of the monomer pre-emulsion added in step A4 to the monomer pre-emulsion added in step A3 is 19:1; the mass ratio of the potassium persulfate solution added in step A4 to the potassium persulfate solution added in step A3 is 19:1.

[0007] A5. Heat the reactor to 60°C, add 10% calcium chloride solution to the emulsion, stir at 200r / min for 30min, centrifuge at 3000r / min for 10-12min, filter, wash with 60°C hot water for 3 times, dry in a spray drying tower to obtain granular modified ABS resin; Furthermore, the mass ratio of the calcium chloride solution to the emulsion is 20:1; the spray drying tower parameters are set as: inlet temperature 180°C, outlet temperature 80°C, feed rate 20-30kg / h, atomizing disk speed 6000-10000r / min; the obtained granular modified ABS resin has a particle size of 1-3mm.

[0008] It should be noted that in the preparation process of the modified ABS resin, the sulfate radical generated by the decomposition of the potassium persulfate free radical initiator activates the double bond of the monomer and initiates chain growth. The high temperature reduces the activation energy of the reaction, and the isocyanate group (-NCO) of the diisocyanate (ADI) reacts with the hydroxyl group on the surface of the ABS particles to undergo a nucleophilic addition reaction to form a carbamate bond (-NHCOO-); at the same time, the potassium persulfate decomposes to generate free radicals, which capture the allyl hydrogen in the butadiene segment to form a chain free radical, which is grafted with the acrylate double bond of glycidyl methacrylate. The benzene ring of the added monomer styrene stabilizes the free radical intermediate through π-π conjugation, thereby increasing the grafting rate, forming a cross-linked network, inhibiting the penetration of solvent molecules, reducing the swelling rate, and improving the solvent resistance; the cross-linked network restricts the movement of the molecular chain, increases the heat deformation temperature, and improves the thermal stability.

[0009] It should be noted again that the unreacted isocyanate group (-NCO) grafted on the modified ABS resin can form a covalent bond with the terminal hydroxyl group of polycarbonate, and the epoxy group forms a hydrogen bond with the amino group of the silane coupling agent, thereby enhancing the interfacial bonding force, inhibiting the phase separation of PC / ABS, and improving the stress cracking resistance. At the same time, -NCO reacts with the phosphate group of triphenyl phosphate (TPP) in the phosphorus-nitrogen synergistic flame retardant to form a phosphoramidate bond (-P(O)-NH-CO-) to promote carbonization. The PO· free radicals generated by the decomposition of TPP quench the H· / OH· in the flame, and cooperate with the nitrogen dilution effect of MCA to improve the flame retardant efficiency. The unreacted epoxy group grafted on the modified ABS resin undergoes a ring-opening reaction with the amino group of the silane coupling agent KH550 to form a secondary amine bond, and the silane coupling agent KH550 is hydrolyzed to generate silanol, which condenses with the surface hydroxyl group of fluorinated nano-silica to form a Si-O-Si bond, forming ABS-KH550-SiO 2In summary, the interfacial bonding between ABS and PC matrix and filler is significantly enhanced, phase separation is inhibited, and the secondary amine bond and Si-O-Si bond jointly construct a physical-chemical dual barrier layer to block the solvent penetration path and prevent coating from biting the bottom. In the freeze-thaw cycle, ABS-KH550-SiO 2 The stable interface structure has strong interface bonding force, which inhibits the expansion of microcracks and improves the freeze-thaw cycle resistance.

[0010] Furthermore, the butadiene content in the core-shell methyl methacrylate-butadiene-styrene polymer is greater than 60%.

[0011] It should be noted that methyl methacrylate-butadiene-styrene not only plays a core role in toughening and improving the impact resistance of composite materials, but can also act as a compatibilizer. The shell layer of methyl methacrylate-butadiene-styrene (methyl methacrylate / styrene) interacts with the ester group (-COO-) of PC and the styrene phase (-Ph) of ABS through polar interactions and similar compatibility mechanisms, reduces interfacial tension, inhibits phase separation during processing and stress, and improves material uniformity. On the other hand, it can optimize processing performance. Its shell layer (methyl methacrylate / styrene) reduces melt viscosity, improves injection molding filling performance, reduces flow marks and warpage, and avoids processing temperature sensitivity caused by toughening agents.

[0012] Furthermore, the preparation steps of the fluorinated nano-silicon dioxide are as follows: The nano-silica was vacuum dried at 120°C for 4 hours, dispersed in anhydrous ethanol, perfluorooctyltriethoxysilane was added, refluxed at 80°C for 6 hours, centrifuged, filtered, washed to neutrality, and dried at 80°C to obtain fluorinated nano-silica; The usage ratio of the nano silicon dioxide, anhydrous ethanol and perfluorooctyltriethoxysilane is 20g:200mL:1g.

[0013] It should be noted that the perfluorinated chains of fluorinated nano-silica cooperate with the hydrophobic segments of the silane coupling agent KH550 to form a dense hydrophobic barrier, which significantly reduces the surface energy of the material and further blocks the penetration of solvents and water. On the other hand, it significantly reduces the water absorption rate, reduces the water expansion stress in the freeze-thaw cycle, and improves the freeze-thaw cycle resistance. After the nanoparticles are evenly dispersed, the maze effect prolongs the solvent diffusion path and reduces the swelling of the composite material. As a filler, it is dispersed in the matrix and limits the slippage of the molecular chain through the pinning effect, thereby improving the bending modulus and tensile strength. It cooperates with the bismaleimide cross-linked network to dissipate energy through reversible bond breakage-reorganization and reduce the creep rate. 2During combustion, it combines with the residual carbon of the phosphorus-nitrogen synergistic flame retardant to form a dense carbon layer, isolating oxygen and heat transfer. The thermal stability of the perfluorinated chain delays the thermal decomposition of the material and suppresses smoke density.

[0014] Furthermore, the phosphorus-nitrogen synergistic flame retardant is triphenyl phosphate and melamine cyanurate, and the mass ratio of triphenyl phosphate to melamine cyanurate is 6:4.

[0015] It should be noted that, on the one hand, phosphorus-nitrogen synergistic flame retardants can form gaseous flame retardants during combustion. At high temperatures, triphenyl phosphate (TPP) decomposes to generate PO· free radicals, which capture H· and OH· free radicals in the flame and interrupt the combustion chain reaction. Melamine cyanurate (MCA) burns to release N 2 NH 3 and H 2 O, dilute the oxygen concentration and reduce the combustion intensity; on the other hand, the phosphorus element of triphenyl phosphate promotes the dehydration and carbonization of PC and ABS to form an expanded carbon layer. The generated nitrogen and a small amount of ammonia expand the carbon layer to form a porous insulation structure, blocking the transfer of heat and oxygen, and producing a nitrogen foaming effect. At the same time, the phosphate group (-PO-OR) of triphenyl phosphate reacts with the -NCO group of the modified ABS resin to generate a phosphoramidate bond, forming a three-dimensional cross-linked network, improving the density of the residual carbon and enhancing the barrier properties; the expanded carbon layer of triphenyl phosphate / melamine cyanurate reacts with the fluorinated nano-SiO 2 The super hydrophobic surface is combined with the carbon layer to isolate heat and the fluorinated layer to block the diffusion of oxygen and volatiles to form a physical-chemical dual fire barrier.

[0016] It should be noted that the main function of phenyl zinc phosphate is to act as a heterogeneous nucleating agent, provide regularly arranged nucleation sites, induce local orderly arrangement of PC molecular chains, improve crystallinity, increase the thermal deformation temperature of the material, reduce the free volume of the amorphous region, and inhibit solvent penetration. 2+ Catalyze the reaction of triphenyl phosphate decomposition products (phosphate esters) to generate zinc phosphate (Zn 3 (PO 4 ) 2 ), promote the formation of dense carbon layer and assist in flame retardancy.

[0017] It should be noted that bismaleimide (BMI) as a cross-linking agent can improve the creep resistance and high temperature dimensional stability of PC / ABS.

[0018] A method for preparing a stress-resistant and coating-resistant PC / ABS composite material comprises the following steps: S1. Add fluorinated nano-silica and fluorinated carbon nanotubes into a dry mixer, dry mix for 2-3 minutes, spray 10% mass fraction of silane coupling agent KH550 / ethanol solution at a spray rate of 2 mL / min, mix for 3-5 minutes, let the material stand for 15-20 minutes, and let it stand in a fume hood with an air flow rate of 0.5-1 m / s for 24 hours to obtain a premix; Furthermore, the usage ratio of the fluorinated nano-silica, the fluorinated carbon nanotubes and the silane coupling agent KH550 / ethanol solution is (3-5) g: (0.5-1) g: (5.7-11.4) mL.

[0019] S2, adding polycarbonate (PC), phosphorus-nitrogen synergistic flame retardant, phenyl zinc phosphate, and bismaleimide into a co-rotating twin-screw extruder through a main feeding port, adding modified ABS resin, core-shell methyl methacrylate-butadiene-styrene polymer, and the premix prepared in step S1 simultaneously through a side feeding port, setting the temperature to 50-260° C., the screw speed to 300 r / min, the torque to 60-70%, and vacuum exhausting at -0.08 MPa, cooling with water at 25° C., pelletizing, centrifuging, and sieving to obtain a blended pellet; Furthermore, the mass ratio of the polycarbonate, the phosphorus-nitrogen synergistic flame retardant, the phenyl zinc phosphate, the bismaleimide, the modified ABS resin, the core-shell methyl methacrylate-butadiene-styrene polymer and the premix prepared in step S1 is (60-65):(8-10):(0.3-0.5):(0.3-0.5):(20-25):(5-8):(4-7); S3, adding the blended pellets into a servo electric injection molding machine, setting the melt temperature to 250°C, the mold temperature to 85°C, the injection pressure to 80MPa, the holding time to 20s, and the cooling time to 30s, demolding after injection molding, placing in a forced convection oven for annealing at 80°C for 2h, and treating with a 40kHz atmospheric pressure plasma processor for 30-40s to obtain a stress-resistant and anti-coating bottom-biting PC / ABS composite material; Furthermore, the parameters of the atmospheric pressure plasma processor are set as follows: power 100W, Ar / O 2 Mixed gas, inter-electrode distance 5mm.

[0020] Compared with the prior art, the present invention has the following beneficial effects: The chemical bonding of the active functional groups of the modified ABS resin with the PC matrix and fillers further inhibits phase separation and strengthens the interface bonding, ensuring the adhesion and long-term durability of the coating; the fluorinated nanofiller is combined with the silane coupling agent to form a dense hydrophobic barrier, effectively blocking water penetration, giving the material excellent freeze-thaw resistance, and avoiding the problem of microcracks caused by water expansion in low temperature environments; the phosphorus-nitrogen flame retardant system synergistically inhibits the combustion process through the dual mechanisms of free radical quenching and carbonization, enhancing the fire safety of the material. Methyl methacrylate-butadiene-styrene maintains the rigidity of the matrix and processing fluidity while improving the impact resistance, while the BMI cross-linked network optimizes stress resistance and high temperature stability through molecular chain movement regulation. Through functional complementarity and interface synergy, each component takes into account freeze-thaw resistance, flame retardancy, mechanical strength and environmental adaptability, providing a reliable solution for high-end engineering plastics in the automotive, electronics and other fields. DETAILED DESCRIPTION

[0021] The following will be described clearly and completely in conjunction with the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0022] Some material sources and parameters are shown in Table 1:

[0023] (1) The preparation steps of modified ABS are as follows: A1. Treat acrylonitrile-butadiene-styrene block copolymer with ozone oxidation at an ozone concentration of 100 ppm and a temperature of 30° C. for 2 h, transfer to water at a temperature of 50° C. and a pH of 7 for hydrolysis for 1 h, rinse with deionized water, and dry to obtain ABS particles; A2. Prepare a sodium dodecyl sulfonate solution with a mass fraction of 0.8%, add 45g of styrene, 15g of diisocyanate and 10g of glycidyl methacrylate to 302g of the sodium dodecyl sulfonate solution and mix, stir and react at a speed of 500r / min at 25°C for 12min, transfer the mixture to a high-pressure homogenizer, circulate emulsification 3 times at a pressure of 60MPa, stand at 25°C for 30min, adjust the pH value to 6.8, and obtain a monomer pre-emulsion; A3. Add 138 g of ABS particles into a reactor under a nitrogen atmosphere, raise the temperature to 75° C., dropwise add 4.5 g of the monomer pre-emulsion prepared in step A1 and 1 g of a 10% potassium persulfate solution at a rate of 0.5 mL / min, and stir at a speed of 200 r / min for 40-80 min to obtain a seed polymerization solution; A4. Heat the reactor to 80°C, add 85.5g of monomer pre-emulsion and 19g of 30% potassium persulfate solution in 3-4 batches at a stirring speed of 150r / min, with an interval of 30min between each batch. After all the pre-emulsions are added, continue stirring and react for 3-4h to obtain an emulsion. A5. The reactor was heated to 60°C, 4800g of 10% calcium chloride solution was added to 240g of emulsion, the mixture was stirred at 200r / min for 30min, centrifuged at 3000r / min for 12min, filtered, washed with hot water at 60°C for 3 times, and dried in a spray drying tower with an inlet temperature of 180°C, an outlet temperature of 80°C, a feed rate of 25kg / h, and an atomizing disk speed of 8000r / min to obtain a granular modified ABS resin.

[0024] (2) The preparation steps of fluorinated nano-silicon dioxide are as follows: 20 g of nano-silica was vacuum dried at 120°C for 4 h, dispersed in 200 mL of anhydrous ethanol, 1 g of perfluorooctyltriethoxysilane was added, the temperature was raised to 80°C, refluxed at 800 r / min for 6 h, the oil bath was closed, naturally cooled to below 40°C, cooled to room temperature while stirring, centrifuged, filtered, washed to neutrality, and dried at 80°C to obtain fluorinated nano-silica. Example 1

[0025] A method for preparing a stress-resistant and coating-resistant PC / ABS composite material comprises the following steps: S1. Add 4 g of fluorinated nano-silica and 0.75 g of fluorinated carbon nanotubes into a dry mixer, dry mix for 2 min, spray 8.6 mL of 10% mass fraction silane coupling agent KH550 / ethanol solution at a spray rate of 2 mL / min, mix for 3 min, let the material stand for 15 min, and let it stand in a fume hood with an air flow rate of 0.5 m / s for 24 h to obtain a premix; S2, 62.5g polycarbonate, 9g phosphorus nitrogen synergistic flame retardant, 0.4g phenyl zinc phosphate, 0.4g bismaleimide are added to the co-rotating twin-screw extruder through the main feeding port, 22.5g modified ABS resin, 6.5g core-shell methyl methacrylate-butadiene-styrene polymer and 5.5g premix prepared in step S1 are added through the side feeding port at the same time, the feeding zone is 50°C, the polycarbonate melting zone (1-3 zone) is 255-260°C, and the modified ABS resin is 22.5g. ABS resin and core-shell methyl methacrylate-butadiene-styrene polymer zone (4-5 zone) 240-245°C, phosphorus nitrogen synergistic flame retardant and premix zone (6-7 zone) 220-230°C, die head 210°C, screw speed 300r / min, torque control 60-70%, vacuum exhaust at -0.08MPa, cut into 2-3mm particles after 25°C water cooling, centrifuge, 10-20 mesh sieve for standby use, to obtain blended pellets; S3, add the blended pellets into the servo electric injection molding machine, set the melt temperature to 250℃, the mold temperature to 85℃, the injection pressure to 80MPa, the holding time to 20s, and the cooling time to 30s, demold after injection molding, place in a forced convection oven for annealing at 80℃ for 2h, and treat with a 40kHz atmospheric pressure plasma processor for 30s, power 100W, Ar / O 2 Mixed gas, inter-electrode distance 5mm, to obtain stress-resistant and paint-resistant PC / ABS composite material. Example 2

[0026] A method for preparing a stress-resistant and coating-resistant PC / ABS composite material comprises the following steps: S1. Add 3 g of fluorinated nano-silica and 0.5 g of fluorinated carbon nanotubes into a dry mixer, dry mix for 2-3 min, spray 5.7 mL of 10% mass fraction silane coupling agent KH550 / ethanol solution at a spray rate of 2 mL / min, mix for 3 min, let the material stand for 15 min, and let it stand in a fume hood with an air flow rate of 0.5 m / s for 24 h to obtain a premix; S2, 60g polycarbonate, 8g phosphorus nitrogen synergistic flame retardant, 0.3g phenyl zinc phosphate, 0.3g bismaleimide are added to the co-rotating twin-screw extruder through the main feeding port, 20g modified ABS resin, 5g core-shell methyl methacrylate-butadiene-styrene polymer and 4g premix prepared in step S1 are added through the side feeding port at the same time, the feeding zone is 50°C, the polycarbonate melting zone (1-3 zone) is 255-260°C, and the modified ABS is 100g. The temperature of the resin and core-shell methyl methacrylate-butadiene-styrene polymer zone (zone 4-5) is 240-245°C, the phosphorus nitrogen synergistic flame retardant and premix zone (zone 6-7) is 220-230°C, the die head is 210°C, the screw speed is 300r / min, the torque is controlled at 60-70%, and the vacuum exhaust is turned on at -0.08MPa. After cooling with water at 25°C, the pellets are cut into 2-3mm particles, centrifuged, and sieved with 10-20 mesh for standby use to obtain the blended pellets; S3, add the blended pellets into the servo electric injection molding machine, set the melt temperature to 250℃, the mold temperature to 85℃, the injection pressure to 80MPa, the holding time to 20s, and the cooling time to 30s, demold after injection molding, place in a forced convection oven for annealing at 80℃ for 2h, and treat with a 40kHz atmospheric pressure plasma processor for 30s, power 100W, Ar / O 2 Mixed gas, inter-electrode distance 5mm, to obtain stress-resistant and paint-resistant PC / ABS composite material. Example 3

[0027] A method for preparing a stress-resistant and coating-resistant PC / ABS composite material comprises the following steps: S1. Add 5 g of fluorinated nano-silica and 1 g of fluorinated carbon nanotubes into a dry mixer, dry mix for 2-3 min, spray 11.4 mL of a 10% mass fraction silane coupling agent KH550 / ethanol solution at a spray rate of 2 mL / min, mix for 3 min, let the material stand for 15 min, and let it stand in a fume hood with an air flow rate of 0.5 m / s for 24 h to obtain a premix; S2, 65g polycarbonate (PC), 10g phosphorus nitrogen synergistic flame retardant, 0.5g phenyl zinc phosphate, 0.5g bismaleimide are added to the co-rotating twin-screw extruder through the main feeding port, 25g modified ABS resin, 8g core-shell methyl methacrylate-butadiene-styrene polymer and 7g premix prepared in step S1 are added through the side feeding port at the same time, the feeding zone is 50°C, the polycarbonate melting zone (1-3 zone) is 255-260°C, and the modified A BS resin and core-shell methyl methacrylate-butadiene-styrene polymer zone (zone 4-5) 240-245°C, phosphorus nitrogen synergistic flame retardant and premix zone (zone 6-7) 220-230°C, die head 210°C, screw speed 300r / min, torque control 60-70%, vacuum exhaust at -0.08MPa, cut into 2-3mm pellets after 25°C water cooling, centrifuge, 10-20 mesh sieve for standby use, to obtain blended pellets; S3, add the blended pellets into the servo electric injection molding machine, set the melt temperature to 250℃, the mold temperature to 85℃, the injection pressure to 80MPa, the holding time to 20s, and the cooling time to 30s, demold after injection molding, place in a forced convection oven for annealing at 80℃ for 2h, and treat with a 40kHz atmospheric pressure plasma processor for 30s, power 100W, Ar / O 2 Mixed gas, inter-electrode distance 5mm, to obtain stress-resistant and paint-resistant PC / ABS composite material. Example 4

[0028] A method for preparing a stress-resistant and coating-resistant PC / ABS composite material comprises the following steps: S1. Add 3.5 g of fluorinated nano-silica and 0.62 g of fluorinated carbon nanotubes into a dry mixer, dry mix for 2-3 min, spray 6.5 mL of 10% mass fraction silane coupling agent KH550 / ethanol solution at a spray rate of 2 mL / min, mix for 3 min, let the material stand for 15 min, and let it stand in a fume hood with an air flow rate of 0.5 m / s for 24 h to obtain a premix; S2, 61.3g polycarbonate (PC), 8.5g phosphorus nitrogen synergistic flame retardant, 0.35g phenyl zinc phosphate, 0.35g bismaleimide are added to the co-rotating twin-screw extruder through the main feeding port, 21.3g modified ABS resin, 5.8g core-shell methyl methacrylate-butadiene-styrene polymer and 4.8g premix prepared in step S1 are added through the side feeding port at the same time, the feeding zone is 50°C, the polycarbonate melting zone (1-3 zone) is 255-26 0℃, modified ABS resin and core-shell methyl methacrylate-butadiene-styrene polymer zone (4-5 zone) 240-245℃, phosphorus nitrogen synergistic flame retardant and premix zone (6-7 zone) 220-230℃, die head 210℃, screw speed 300r / min, torque control at 60-70%, vacuum exhaust at -0.08MPa, cut into 2-3mm particles after 25℃ water cooling, centrifuge, 10-20 mesh sieve for standby use, to obtain blended pellets; S3, add the blended pellets into the servo electric injection molding machine, set the melt temperature to 250℃, the mold temperature to 85℃, the injection pressure to 80MPa, the holding time to 20s, and the cooling time to 30s, demold after injection molding, place in a forced convection oven for annealing at 80℃ for 2h, and treat with a 40kHz atmospheric pressure plasma processor for 30s, power 100W, Ar / O 2 Mixed gas, inter-electrode distance 5mm, to obtain stress-resistant and paint-resistant PC / ABS composite material. Example 5

[0029] A method for preparing a stress-resistant and coating-resistant PC / ABS composite material comprises the following steps: S1. Add 4.5 g of fluorinated nano-silica and 0.82 g of fluorinated carbon nanotubes into a dry mixer, dry mix for 2-3 min, spray 8.9 mL of 10% mass fraction silane coupling agent KH550 / ethanol solution at a spray rate of 2 mL / min, mix for 3 min, let the material stand for 15 min, and let it stand in a fume hood with an air flow rate of 0.5 m / s for 24 h to obtain a premix; S2, 63.8g polycarbonate (PC), 9.5g phosphorus nitrogen synergistic flame retardant, 0.45g phenyl zinc phosphate, 0.45g bismaleimide are added to the co-rotating twin-screw extruder through the main feeding port, 22.8g modified ABS resin, 7.3g core-shell methyl methacrylate-butadiene-styrene polymer and 6.3g premix prepared in step S1 are added through the side feeding port at the same time, the feeding zone is 50°C, the polycarbonate melting zone (1-3 zone) is 255-26 0℃, modified ABS resin and core-shell methyl methacrylate-butadiene-styrene polymer zone (4-5 zone) 240-245℃, phosphorus nitrogen synergistic flame retardant and premix zone (6-7 zone) 220-230℃, die head 210℃, screw speed 300r / min, torque control at 60-70%, vacuum exhaust at -0.08MPa, cut into 2-3mm particles after 25℃ water cooling, centrifuge, 10-20 mesh sieve for standby use, to obtain blended pellets; S3, add the blended pellets into the servo electric injection molding machine, set the melt temperature to 250℃, the mold temperature to 85℃, the injection pressure to 80MPa, the holding time to 20s, and the cooling time to 30s, demold after injection molding, place in a forced convection oven for annealing at 80℃ for 2h, and treat with a 40kHz atmospheric pressure plasma processor for 30s, power 100W, Ar / O 2 Mixed gas, inter-electrode distance 5mm, to obtain stress-resistant and paint-resistant PC / ABS composite material.

[0030] Comparative Example 1 A method for preparing a stress-resistant and coating-resistant PC / ABS composite material comprises the following steps: S1. Add 4 g of fluorinated nano-silica and 0.75 g of fluorinated carbon nanotubes into a dry mixer, dry mix for 2 min, spray 8.6 mL of 10% mass fraction silane coupling agent KH550 / ethanol solution at a spray rate of 2 mL / min, mix for 3 min, let the material stand for 15 min, and let it stand in a fume hood with an air flow rate of 0.5 m / s for 24 h to obtain a premix; S2, 62.5g polycarbonate (PC), 9g phosphorus nitrogen synergistic flame retardant, 0.4g phenyl zinc phosphate, 0.4g bismaleimide were added to the co-rotating twin-screw extruder through the main feed port, and 22.5g ABS resin, 6.5 g of core-shell methyl methacrylate-butadiene-styrene polymer and 5.5 g of the premix prepared in step S1 are added simultaneously through the side feeding port, the feeding zone is 50° C., the polycarbonate melting zone (zones 1-3) is 255-260° C., the modified ABS resin and core-shell methyl methacrylate-butadiene-styrene polymer zone (zones 4-5) is 240-245° C., the phosphorus nitrogen synergistic flame retardant and premix zone (zones 6-7) is 220-230° C., the die is 210° C., the screw speed is 300 r / min, the torque is controlled at 60-70%, vacuum exhaust is turned on at -0.08 MPa, the mixture is cooled in water at 25° C., cut into 2-3 mm particles, centrifuged, and sieved with 10-20 mesh for standby use to obtain blended pellets; S3, add the blended pellets into the servo electric injection molding machine, set the melt temperature to 250℃, the mold temperature to 85℃, the injection pressure to 80MPa, the holding time to 20s, and the cooling time to 30s, demold after injection molding, place in a forced convection oven for annealing at 80℃ for 2h, and treat with a 40kHz atmospheric pressure plasma processor for 30s, power 100W, Ar / O 2 Mixed gas, inter-electrode distance 5mm, to obtain stress-resistant and paint-resistant PC / ABS composite material.

[0031] The difference between this comparative example and Example 1 is that the modified ABS resin is not used, but the unmodified ABS resin (acrylonitrile-butadiene-styrene copolymer) is used.

[0032] Comparative Example 2 A method for preparing a stress-resistant and coating-resistant PC / ABS composite material comprises the following steps: S1. Add 4 g of nano-silica and 0.75 g of fluorinated carbon nanotubes into a dry mixer, dry mix for 2 min, spray 8.6 mL of 10% mass fraction silane coupling agent KH550 / ethanol solution at a spray rate of 2 mL / min, mix for 3 min, let the material stand for 15 min, and let it stand in a fume hood with an air flow rate of 0.5 m / s for 24 h to obtain a premix; S2, 62.5g polycarbonate, 9g phosphorus nitrogen synergistic flame retardant, 0.4g phenyl zinc phosphate, 0.4g bismaleimide are added to the co-rotating twin-screw extruder through the main feeding port, 22.5g modified ABS resin, 6.5g core-shell methyl methacrylate-butadiene-styrene polymer and 5.5g premix prepared in step S1 are added through the side feeding port at the same time, the feeding zone is 50°C, the polycarbonate melting zone (1-3 zone) is 255-260°C, and the modified ABS resin is 22.5g. ABS resin and core-shell methyl methacrylate-butadiene-styrene polymer zone (4-5 zone) 240-245°C, phosphorus nitrogen synergistic flame retardant and premix zone (6-7 zone) 220-230°C, die head 210°C, screw speed 300r / min, torque control 60-70%, vacuum exhaust at -0.08MPa, cut into 2-3mm particles after 25°C water cooling, centrifuge, 10-20 mesh sieve for standby use, to obtain blended pellets; S3, add the blended pellets into the servo electric injection molding machine, set the melt temperature to 250℃, the mold temperature to 85℃, the injection pressure to 80MPa, the holding time to 20s, and the cooling time to 30s, demold after injection molding, place in a forced convection oven for annealing at 80℃ for 2h, and treat with a 40kHz atmospheric pressure plasma processor for 30s, power 100W, Ar / O 2 Mixed gas, inter-electrode distance 5mm, to obtain stress-resistant and paint-resistant PC / ABS composite material.

[0033] The difference between this comparative example and Example 1 is that fluorinated nano-silica is not used, but nano-silica that is not modified by fluorination is used.

[0034] test: 1. Stress resistance Environmental stress cracking resistance: GB / T 43316.2-2023 Determination of environmental stress cracking resistance (ESC) of plastics Part 2: Constant tensile load method Creep amount: GB / T 2567-2021 Test method for properties of resin castings 2. Prevent coating from biting the bottom Coating adhesion: spray UV topcoat on clean ABS plastic plate, cure in UV machine for 5 minutes, test the cured coating according to GB / T 9286-1998 Cross-cut test for paint and varnish film, and observe its appearance; Solvent resistance: GB / T 11547-2008 Determination of resistance of plastics to liquid chemical reagents 3. Flame retardant properties GB / T 2408-2021 Determination of combustion performance of plastics - Horizontal and vertical methods 4. Mechanical properties Impact resistance: "ASTM D256-97 Plastics impact test method" Bending properties: GB / T 9341-2008 Determination of bending properties of plastics Tensile properties: GB / T 1040.1-2018 Determination of tensile properties of plastics Part 1: General principles 5. Freeze-thaw cycle resistance (flexural modulus retention rate) Flexural modulus: GB / T 9341-2008 Determination of flexural properties of plastics Single freeze-thaw cycle: water temperature 15±5℃, water volume 1.0~1.5 L / (m²·min), spraying and soaking for 1h; surface temperature 20±5℃, humidity ≥80%, constant temperature and moisturizing for 1h; surface temperature -20±5℃ (cooling to target temperature in 1h), low temperature freezing for 5h; surface temperature rises to 20±5℃, humidity ≥80%, heating and thawing for 1h; Repeat 12 times; Bending performance retention rate = E 冻融循环后 / E 初始 ×100% 6. High temperature stability (tensile strength retention rate) GB / T 7141-2008 Test methods for thermal aging of plastics Nominal thickness of the specimen: 0.3±0.01 mm, test temperature: 120-150℃, time period: 500h, ventilation rate: 10±2 times / h; Tensile strength retention rate = σ 老化后 / σ 初始 ×100% VII. Results Summary

[0035] It can be seen from Table 2 that the stress-resistant and paint-resistant PC / ABS composite materials prepared in Examples 1-5 have excellent mechanical properties, flame retardant properties, stress resistance, paint-resistant ability, freeze-thaw cycle resistance and high temperature stability.

[0036] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

[0037] In the description of the specification, the description with reference to the terms "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0038] The above contents are merely examples and explanations of the present invention. Those skilled in the art may make various modifications or additions to the specific embodiments described or replace them in a similar manner. As long as they do not deviate from the invention or exceed the scope defined by the claims, they shall all fall within the protection scope of the present invention.

Claims

1. A stress-resistant and anti-coating bottom-biting PC / ABS composite material, characterized by: The following raw material components are included by weight: Polycarbonate 60-65 parts; Modified ABS resin 20-25 parts; 5-8 parts of core-shell methyl methacrylate-butadiene-styrene polymer; 3-5 parts of fluorinated nano silicon dioxide; 0.5-1 part of fluorinated carbon nanotubes; 8-10 parts of phosphorus-nitrogen synergistic flame retardant; 0.3-0.5 part of phenyl zinc phosphate; 0.3-0.5 parts of bismaleimide; Silane coupling agent KH550 0.5-1 part; The preparation of the modified ABS resin comprises the following specific steps: A1. Treat acrylonitrile-butadiene-styrene block copolymer with ozone oxidation at an ozone concentration of 50-100 ppm and a temperature of 25-40° C. for 1-3 h, transfer to water at a temperature of 40-60° C. and a pH of 7-9 for hydrolysis for 0.5-2 h, rinse with deionized water, and dry to obtain ABS particles; A2, prepare sodium dodecyl sulfonate solution, add styrene, diisocyanate and glycidyl methacrylate into the sodium dodecyl sulfonate solution and mix, stir and react at 25°C at a speed of 500r / min for 10-15min, transfer the mixture to a high-pressure homogenizer, circulate emulsification 3 times at a pressure of 60MPa, stand at 25°C for 30min, adjust the pH value to 6.5-7, and obtain a monomer pre-emulsion; A3. Add ABS particles into a reactor under a nitrogen atmosphere, raise the temperature to 75° C., dropwise add part of the monomer pre-emulsion prepared in step A1 and part of the potassium persulfate solution at a rate of 0.5 mL / min, and stir at a speed of 200 r / min for 40-80 min to obtain a seed polymerization solution; A4. Heat the reactor to 80°C, add the remaining monomer pre-emulsion and the remaining potassium persulfate solution in 3-4 batches at a stirring speed of 150 r / min, with an interval of 30 minutes between each batch. After all the pre-emulsion is added, continue stirring and reacting for 3-4 hours to obtain an emulsion; A5. Heat the reactor to 60°C, add 10% calcium chloride solution into the emulsion, stir at 200r / min for 30min, centrifuge at 3000r / min for 10-12min, filter, wash with 60°C hot water for 3 times, dry in a spray drying tower to obtain granular modified ABS resin.

2. The stress-resistant and anti-painting bottom-biting PC / ABS composite material according to claim 1, characterized in that: In the step A2, the mass ratio of the sodium dodecyl sulfonate solution, styrene, diisocyanate and glycidyl methacrylate is (270-310):(40-50):(13.5-16.5):(9-11); the sodium dodecyl sulfonate solution is prepared from sodium dodecyl sulfonate and deionized water, and the mass ratio of the sodium dodecyl sulfonate to deionized water is 1:(100-150).

3. The stress-resistant and anti-painting bottom-biting PC / ABS composite material according to claim 1, characterized in that: In the step A3, the mass ratio of the ABS particles, the monomer pre-emulsion and the potassium persulfate solution is (135-140):(4-5):1; the potassium persulfate solution is prepared from potassium persulfate and deionized water, and the mass ratio of potassium persulfate to deionized water is 1:(9-11).

4. The stress-resistant and anti-painting bottom-biting PC / ABS composite material according to claim 1, characterized in that: In the step A4, the potassium persulfate solution is prepared from potassium persulfate and deionized water, and the mass ratio of the potassium persulfate to the deionized water is 3:(6-8).

5. The stress-resistant and anti-painting bottom-biting PC / ABS composite material according to claim 1, characterized in that: The mass ratio of the monomer pre-emulsion added in step A4 to the monomer pre-emulsion added in step A3 is 19:1; the mass ratio of the potassium persulfate solution added in step A4 to the potassium persulfate solution added in step A3 is 19:

1.

6. The stress-resistant and anti-painting bottom-biting PC / ABS composite material according to claim 1, characterized in that: In the step A5, the mass ratio of the calcium chloride solution to the emulsion is 20:1; the parameters of the spray drying tower are set as follows: inlet temperature 180°C, outlet temperature 80°C, feed rate 20-30kg / h, atomizing disk speed 6000-10000r / min; the particle size of the obtained granular modified ABS resin is 1-3mm.

7. The stress-resistant and anti-painting bottom-biting PC / ABS composite material according to claim 1, characterized in that: The butadiene content in the core-shell methyl methacrylate-butadiene-styrene polymer is greater than 60%.

8. The stress-resistant and anti-painting bottom-biting PC / ABS composite material according to claim 1, characterized in that: The phosphorus-nitrogen synergistic flame retardant is triphenyl phosphate and melamine cyanurate, and the mass ratio of the triphenyl phosphate to melamine cyanurate is 6:

4.

9. A method for preparing a stress-resistant and coating-resistant PC / ABS composite material as claimed in any one of claims 1 to 8 is as follows: S1. Add fluorinated nano-silica and fluorinated carbon nanotubes into a dry mixer, dry mix for 2-3 minutes, spray 10% mass fraction of silane coupling agent KH550 / ethanol solution at a spray rate of 2 mL / min, mix for 3-5 minutes, let the material stand for 15-20 minutes, and let it stand in a fume hood with an air flow rate of 0.5-1 m / s for 24 hours to obtain a premix; The usage ratio of the fluorinated nano-silica, the fluorinated carbon nanotubes and the silane coupling agent KH550 / ethanol solution is (3-5) g: (0.5-1) g: (5.7-11.4) mL; S2, adding polycarbonate, phosphorus-nitrogen synergistic flame retardant, phenyl zinc phosphate, and bismaleimide into a co-rotating twin-screw extruder through a main feeding port, and simultaneously adding modified ABS resin, core-shell methyl methacrylate-butadiene-styrene polymer, and the premix prepared in step S1 through a side feeding port, setting the temperature to 50-260° C., the screw speed to 300 r / min, the torque to 60-70%, and vacuum exhausting at -0.08 MPa, cooling with water at 25° C., pelletizing, centrifuging, and sieving to obtain a blended pellet; The mass ratio of the polycarbonate, the phosphorus-nitrogen synergistic flame retardant, phenyl zinc phosphate, bismaleimide, modified ABS resin, core-shell methyl methacrylate-butadiene-styrene polymer and the premix prepared in step S1 is (60-65):(8-10):(0.3-0.5):(0.3-0.5):(20-25):(5-8):(4-7); S3. Add the blended pellets into a servo electric injection molding machine, set the melt temperature to 250°C, the mold temperature to 85°C, the injection pressure to 80MPa, the holding time to 20s, and the cooling time to 30s. Demould the mixture after injection molding, place it in a forced convection oven for annealing at 80°C for 2h, and treat it with a 40kHz atmospheric pressure plasma processor for 30-40s to obtain a stress-resistant and anti-coating bottoming PC / ABS composite material.

10. The method for preparing a stress-resistant and paint-resistant PC / ABS composite material according to claim 9, characterized in that: In step S3, the parameters of the atmospheric pressure plasma processor are set as: power 100W, Ar / O2 mixed gas, and inter-electrode distance 5mm.

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