A PC / ABS composite material resistant to stress and preventing paint biting and its preparation method

Abstract

The present invention discloses a PC / ABS composite material with stress resistance and anti-painting lifting and its preparation method, relating to the technical field of engineering plastic alloys. A PC / ABS composite material with stress resistance and anti-painting lifting comprises the following raw material components in parts by weight: 60-65 parts of polycarbonate; 20-25 parts of modified ABS resin; 5-8 parts of core-shell methyl methacrylate-butadiene-styrene polymer; 3-5 parts of fluorinated nano-silica; 0.5-1 part of fluorinated carbon nanotubes; 8-10 parts of phosphorus-nitrogen synergistic flame retardant; 0.3-0.5 part of zinc phenylphosphate; 0.3-0.5 part of bismaleimide; 0.5-1 part of silane coupling agent KH550. Through functional complementarity and interface synergy of each component, it takes into account stress resistance, anti-painting lifting, freeze-thaw resistance, flame retardancy, mechanical strength and environmental adaptability, providing a reliable solution for high-end engineering plastics in fields such as automobiles and electronics.

Description

Technical Field

[0001] The present invention relates to the technical field of engineering plastic alloys, and specifically to a PC / ABS composite material with stress resistance and anti-coating biting bottom and a preparation method thereof. Background Art

[0002] Alloy materials of polycarbonate (PC) and acrylonitrile-butadiene-styrene copolymer (ABS) (PC / ABS) are widely used in the fields of automobiles, electronics and consumer products due to their comprehensive performance advantages. The high strength and heat resistance of PC are complementary to the processability and impact resistance of ABS, but the insufficient compatibility between the two easily leads to phase separation and weak interfacial bonding, and problems such as mechanical property attenuation and poor dimensional stability are likely to occur 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, defects such as coating peeling, swelling and cracking are likely to occur.

[0003] In the prior art, flame retardant modification and anti-permeation design often rely on single functional components. For example, although halogen-based flame retardants have high efficiency, they have poor environmental friendliness, and although inorganic fillers can improve thermal stability, they exacerbate interfacial defects. In addition, conventional hydrophobic treatments mostly use physical coatings, which have shortcomings such as insufficient adhesion and poor durability, and it is difficult to cope with the microcrack propagation caused by freeze-thaw cycles or solvent erosion. The frequent occurrence of coating biting bottom phenomenon further restricts the application of materials in high-end scenarios. How to achieve the synergistic improvement of flame retardancy, anti-permeation, mechanical strength and interfacial stability through material system innovation has become a technical difficulty that the industry urgently needs to break through. Summary of the Invention

[0004] The purpose of the present invention is to provide a PC / ABS composite material with stress resistance and anti-coating biting bottom and a preparation method thereof to solve the problems raised in the background art.

[0005] To achieve the above purpose, the present invention provides the following technical solutions:

[0006] A PC / ABS composite material with stress resistance and anti-coating biting bottom comprises the following raw material components by weight:

[0007] 60-65 parts of polycarbonate;

[0008] 20-25 parts of modified ABS resin;

[0009] 5-8 parts of core-shell methyl methacrylate-butadiene-styrene polymer;

[0010] 3-5 parts of fluorinated nano-silica;

[0011] 0.5-1 part of fluorinated carbon nanotubes;

[0012] 8 - 10 parts of phosphorus - nitrogen synergistic flame retardant;

[0013] 0.3 - 0.5 parts of zinc phenylphosphate;

[0014] 0.3 - 0.5 parts of bismaleimide;

[0015] 0.5 - 1 part of silane coupling agent KH550;

[0016] Further, the preparation of the modified ABS resin is to modify the acrylonitrile - butadiene - styrene block copolymer, and the specific steps are as follows:

[0017] A1. Carry out ozone oxidation treatment on the acrylonitrile - butadiene - styrene block copolymer, with an ozone concentration of 50 - 100 ppm, a temperature of 25 - 40 °C, for 1 - 3 h, then transfer it to water with 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;

[0018] A2. Prepare a sodium dodecyl sulfate solution, add styrene, diisocyanate, and glycidyl methacrylate to the sodium dodecyl sulfate solution and mix them. Stir and react at a speed of 500 r / min at 25 °C for 10 - 15 min. Transfer the mixture to a high - pressure homogenizer, circulate and emulsify it 3 times under a pressure of 60 MPa, let it stand at 25 °C for 30 min, and adjust the pH value to 6.5 - 7 to obtain a monomer pre - emulsion;

[0019] Further, the mass ratio of the sodium dodecyl sulfate solution, styrene, diisocyanate, and glycidyl methacrylate is (270 - 310):(40 - 50):(13.5 - 16.5):(9 - 11); the sodium dodecyl sulfate solution is prepared from sodium dodecyl sulfate and deionized water, and the mass ratio of sodium dodecyl sulfate to deionized water is 1:(100 - 150);

[0020] A3. Under a nitrogen atmosphere, add the ABS particles to the reaction kettle, heat up to 75 °C, and dropwise add part of the monomer pre - emulsion and part of the potassium persulfate solution prepared in step A2 at a rate of 0.5 mL / min, and stir and react at a speed of 200 r / min for 40 - 80 min to obtain a seed polymerization liquid;

[0021] Further, the mass ratio of the ABS particles, monomer pre - emulsion, and 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).

[0022] 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;

[0023] 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.

[0024] 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;

[0025] 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.

[0026] 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.

[0027] It should be noted again that the unreacted isocyanate groups (-NCO) grafted on the modified ABS resin can form covalent bonds with the terminal hydroxyl groups of polycarbonate, and the epoxy groups can form hydrogen bonds with the amino groups of the silane coupling agent, 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 groups of triphenyl phosphate (TPP) in the phosphorus-nitrogen synergistic flame retardant to form phosphoramide ester bonds (-P(O)-NH-CO-), promoting carbonization. The PO· free radicals decomposed from TPP quench H· / OH· in the flame, synergistically with the nitrogen dilution effect of MCA, improving the flame retardancy efficiency. The unreacted epoxy groups grafted on the modified ABS resin undergo ring-opening reactions with the amino groups of the silane coupling agent KH550 to form secondary amine bonds, and the silanol formed by the hydrolysis of the silane coupling agent KH550 condenses with the surface hydroxyl groups of fluorinated nano-silica to form Si-O-Si bonds, forming a stable interfacial structure of ABS-KH550-SiO2. In summary, the interfacial bonding force between ABS and the PC matrix and fillers is significantly enhanced, phase separation is inhibited, and the secondary amine bonds and Si-O-Si bonds jointly construct a physical-chemical double barrier layer, blocking the solvent penetration path and preventing paint biting. In the freeze-thaw cycle, the stable interfacial structure of ABS-KH550-SiO2 has strong interfacial bonding force, inhibits the propagation of microcracks, and improves the freeze-thaw cycle resistance performance.

[0028] Further, the butadiene content in the core-shell methyl methacrylate-butadiene-styrene polymer is greater than 60%.

[0029] It should be noted that methyl methacrylate-butadiene-styrene not only plays a core role in toughening and improving the impact resistance of the composite material. On the one hand, it can also act as a compatibilizer. The shell layer (methyl methacrylate / styrene) of methyl methacrylate-butadiene-styrene reduces the interfacial tension with the ester groups (-COO-) of PC and the styrene phase (-Ph) of ABS through polar interactions and the similar compatibility mechanism, inhibits phase separation during processing and under stress, and improves the material homogeneity. On the other hand, it can optimize the processing performance. Its shell layer (methyl methacrylate / styrene) reduces the melt viscosity, improves the injection molding filling performance, reduces flow marks and warping, and avoids the processing temperature sensitivity caused by the toughening agent.

[0030] Further, the preparation steps of the fluorinated nano-silica are as follows:

[0031] Vacuum dry the nano-silica at 120 °C for 4 h, disperse it in anhydrous ethanol, add perfluorooctyltriethoxysilane, reflux at 80 °C for 6 h, centrifuge, filter, wash until neutral, and dry at 80 °C to obtain fluorinated nano-silica;

[0032] The dosage ratio of the nano-silica, absolute ethanol and perfluorooctyltriethoxysilane is 20 g: 200 mL: 1 g.

[0033] It should be noted that the perfluoro chains of the fluorinated nano-silica and the hydrophobic segments of the silane coupling agent KH550 cooperate to form a dense hydrophobic barrier. On the one hand, it significantly reduces the surface energy of the material, further blocks the penetration of solvents and moisture, and on the other hand, it significantly reduces the water absorption rate, reduces the moisture expansion stress during freeze-thaw cycles, and improves the freeze-thaw cycle resistance performance; after the nano-particles are evenly dispersed, the solvent diffusion path is extended through the maze effect, reducing the swelling of the composite material; as a filler dispersed in the matrix, the molecular chain slip is restricted through the pinning effect, enhancing the flexural modulus and tensile strength; cooperating with the bismaleimide cross-linked network, the energy is dissipated through the reversible bond breakage-recombination, reducing the creep rate; when the fluorinated SiO2 burns, it combines with the residual carbon of the phosphorus-nitrogen synergistic flame retardant to form a dense carbon layer, isolating the transfer of oxygen and heat, and the thermal stability of the perfluoro chain delays the thermal decomposition of the material and inhibits the smoke density.

[0034] Further, the phosphorus-nitrogen synergistic flame retardant is triphenyl phosphate and melamine cyanurate, and the mass ratio of the triphenyl phosphate and melamine cyanurate is 6:4.

[0035] It should be noted that, on the one hand, the phosphorus-nitrogen synergistic flame retardant can form gas flame retardancy during combustion. At high temperatures, triphenyl phosphate (TPP) decomposes to generate PO· free radicals, and PO· captures H· and OH· free radicals in the flame, interrupting the combustion chain reaction. Melamine cyanurate (MCA) burns to release N2, NH3 and H2O, diluting the oxygen concentration and reducing the combustion intensity; on the other hand, the phosphorus element of triphenyl phosphate promotes the dehydration carbonization of PC and ABS, forming an expanded carbon layer. The generated nitrogen and a small amount of ammonia cause the carbon layer to expand, forming a porous heat-insulating structure, blocking the transfer of heat and oxygen, and generating 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 phosphoramide ester bonds, forming a three-dimensional cross-linked network, improving the compactness of the residual carbon and enhancing the barrier property; the expanded carbon layer of triphenyl phosphate / melamine cyanurate and the superhydrophobic surface of the fluorinated nano-SiO2 are combined. The carbon layer isolates heat, and the fluorinated layer blocks the diffusion of oxygen and volatile components, forming a physical-chemical double fire prevention barrier.

[0036] It should be noted that the main function of zinc phenylphosphate is to act as a heterogeneous nucleating agent, providing regularly arranged crystal nucleation sites, inducing the local ordered arrangement of PC molecular chains, increasing the crystallinity, raising the heat distortion temperature of the material, reducing the free volume in the amorphous region, and inhibiting the penetration of solvents. In addition, Zn 2+ catalyzes the reaction of the decomposition product (phosphate ester) of triphenyl phosphate to generate zinc phosphate (Zn3(PO4)2), promoting the formation of a dense carbon layer and assisting in flame retardancy.

[0037] It should be noted that as a crosslinking agent, bismaleimide (BMI) can improve the creep resistance and high-temperature dimensional stability of PC / ABS.

[0038] A method for preparing a PC / ABS composite material with stress resistance and anti-priming is as follows:

[0039] S1. Add fluorinated nano-silica and fluorinated carbon nanotubes to a dry mixer, dry mix for 2 - 3 min, spray in a 10% silane coupling agent KH550 / ethanol solution at a spraying speed of 2 mL / min, mix for 3 - 5 min, discharge and let stand for 15 - 20 min, and let stand in a fume hood with an air flow rate of 0.5 - 1 m / s for 24 h to obtain a premix.

[0040] Furthermore, the dosage ratio of the fluorinated nano-silica, fluorinated carbon nanotubes, and silane coupling agent KH550 / ethanol solution is (3 - 5) g : (0.5 - 1) g : (5.7 - 11.4) mL.

[0041] S2. Add polycarbonate (PC), a phosphorus-nitrogen synergistic flame retardant, zinc phenylphosphate, and bismaleimide through the main feed port to a co-rotating twin-screw extruder, and synchronously add the modified ABS resin, core-shell methyl methacrylate-butadiene-styrene polymer, and the premix prepared in step S1 through the side feed port. Set the temperature at 50 - 260 °C, the screw speed at 300 r / min, control the torque at 60 - 70%, start vacuum exhaust at -0.08 MPa, cool and pelletize with 25 °C water, centrifuge, and screen to obtain blended pellets.

[0042] Furthermore, the mass ratio of the polycarbonate, phosphorus-nitrogen synergistic flame retardant, zinc phenylphosphate, 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).

[0043] S3. Add the blended pellets to a servo-electric injection molding machine, set the melt temperature at 250 °C, the mold temperature at 85 °C, the injection pressure at 80 MPa, the holding pressure time at 20 s, and the cooling time at 30 s. Demold after injection molding, anneal in a forced convection oven at 80 °C for 2 h, and treat with a 40 kHz atmospheric pressure plasma processor for 30 - 40 s to obtain a PC / ABS composite material with stress resistance and anti-priming.

[0044] Furthermore, the parameters of the atmospheric pressure plasma processor are set as follows: power 100 W, Ar / O2 mixed gas, and the electrode spacing 5 mm.

[0045] Compared with the prior art, the present invention has the following beneficial effects:

[0046] 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 interfacial bonding, ensuring the coating adhesion and long-term durability; the fluorinated nano-fillers combined with silane coupling agents form a dense hydrophobic barrier, effectively blocking moisture penetration, endowing the material with excellent freeze-thaw resistance, and avoiding microcrack problems caused by water expansion in low-temperature environments; the phosphorus-nitrogen flame retardant system synergistically inhibits the combustion process through dual mechanisms of free radical quenching and char formation, enhancing the fire safety of the material. Methyl methacrylate-butadiene-styrene improves the impact resistance while maintaining the matrix rigidity and processing fluidity, while the BMI cross-linked network optimizes the stress resistance and high-temperature stability through molecular chain movement regulation. Through functional complementarity and interfacial 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 fields such as automotive and electronics. Detailed implementation manners

[0047] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0048] The sources and parameters of some materials are shown in Table 1:

[0049]

[0050] (1) The preparation steps of the modified ABS are as follows:

[0051] A1. Perform ozone oxidation treatment on acrylonitrile-butadiene-styrene block copolymer, with an ozone concentration of 100 ppm, a temperature of 30 °C, and a treatment time of 2 h. Transfer it 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;

[0052] A2. Prepare a sodium dodecyl sulfate solution with a mass fraction of 0.8%. Add 45 g of styrene, 15 g of diisocyanate, and 10 g of glycidyl methacrylate to 302 g of the sodium dodecyl sulfate solution and mix. Stir and react at a rotation speed of 500 r / min at 25 °C for 12 min. Transfer the mixture to a high-pressure homogenizer, circulate and emulsify it 3 times under a pressure of 60 MPa, let it stand at 25 °C for 30 min, and adjust the pH value to 6.8 to obtain a monomer pre-emulsion;

[0053] A3. Add 138 g of ABS particles to the reaction kettle under a nitrogen atmosphere, heat up to 75 °C, and dropwise add 4.5 g of the monomer pre-emulsion prepared in step A1 and 1 g of a potassium persulfate solution with a mass fraction of 10% at a rate of 0.5 mL / min, and stir and react at a rotation speed of 200 r / min for 40 - 80 min to obtain a seed polymerization solution;

[0054] A4. Heat the reaction kettle to 80 °C, and add 85.5 g of the monomer pre-emulsion and 19 g of a potassium persulfate solution with a mass fraction of 30% in 3 - 4 batches under the stirring condition of a rotation speed of 150 r / min, with an interval of 30 min between each batch. After all are added, continuously stir and react for 3 - 4 h to obtain an emulsion;

[0055] A5. Heat the reaction kettle to 60 °C, add 4800 g of a calcium chloride solution with a mass fraction of 10% to 240 g of the emulsion, stir and react at a rotation speed of 200 r / min for 30 min, centrifuge at a rotation speed of 3000 r / min for 12 min, filter, wash 3 times with hot water at 60 °C, and perform drying treatment using a spray drying tower, with an inlet temperature of 180 °C, an outlet temperature of 80 °C, a feeding rate of 25 kg / h, and a rotation speed of the atomizing disk of 8000 r / min to obtain granular modified ABS resin.

[0056] (2) The preparation steps of fluorinated nano-silica are as follows:

[0057] Vacuum-dry 20 g of nano-silica at 120 °C for 4 h, disperse it in 200 mL of absolute ethanol, add 1 g of perfluorooctyltriethoxysilane, heat up to 80 °C, reflux at a rotation speed of 800 r / min for 6 h, turn off the oil bath, naturally cool to below 40 °C, keep stirring and cool to room temperature, centrifuge, filter, wash until neutral, and dry at 80 °C to obtain fluorinated nano-silica. Example 1

[0058] The preparation method of a PC / ABS composite material with stress resistance and anti-painting lifting is as follows:

[0059] S1. Add 4 g of fluorinated nano-silica and 0.75 g of fluorinated carbon nanotubes to a dry mixer, dry mix for 2 min, spray into 8.6 mL of a silane coupling agent KH550 / ethanol solution with a mass fraction of 10% at a spray speed of 2 mL / min, mix for 3 min, discharge and let stand for 15 min, and let stand in a fume hood with an air flow rate of 0.5 m / s for 24 h to obtain a premix;

[0060] S2. Add 62.5 g of polycarbonate, 9 g of phosphorus-nitrogen synergistic flame retardant, 0.4 g of zinc phenylphosphate, and 0.4 g of bismaleimide into a co-rotating twin-screw extruder through the main feeding port. Synchronously add 22.5 g of modified ABS resin, 6.5 g of core-shell methyl methacrylate-butadiene-styrene polymer, and 5.5 g of the premix prepared in step S1 through the side feeding port. The feeding zone is at 50 °C, the polycarbonate melting zone (zones 1 - 3) is at 255 - 260 °C, the modified ABS resin and core-shell methyl methacrylate-butadiene-styrene polymer zone (zones 4 - 5) is at 240 - 245 °C, the phosphorus-nitrogen synergistic flame retardant and premix zone (zones 6 - 7) is at 220 - 230 °C, and the die head is at 210 °C. The screw speed is 300 r / min, the torque is controlled at 60 - 70%, and vacuum exhaust is started under -0.08 MPa. Cut into 2 - 3 mm pellets by water cooling at 25 °C, centrifuge, and sieve with 10 - 20 meshes for standby to obtain the blended pellets;

[0061] S3. Add the blended pellets into a servo-electric injection molding machine. Set the melt temperature at 250 °C, the mold temperature at 85 °C, the injection pressure at 80 MPa, the holding pressure time at 20 s, and the cooling time at 30 s. Demold after injection molding and anneal in a forced convection oven at 80 °C for 2 h, and then treat with a 40 kHz atmospheric pressure plasma processor for 30 s, with a power of 100 W, an Ar / O2 mixed gas, and a pole pitch of 5 mm to obtain the PC / ABS composite material with stress resistance and anti-coating biting. Example 2

[0062] A preparation method of a PC / ABS composite material with stress resistance and anti-coating biting is as follows:

[0063] 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 into 5.7 mL of a 10% silane coupling agent KH550 / ethanol solution at a spraying speed of 2 mL / min, mix for 3 min, discharge and let stand for 15 min, and then let stand in a fume hood with an air flow rate of 0.5 m / s for 24 h to obtain the premix;

[0064] S2. Add 60 g of polycarbonate, 8 g of a phosphorus-nitrogen synergistic flame retardant, 0.3 g of zinc phenylphosphate, and 0.3 g of bismaleimide into a co-rotating twin-screw extruder through the main feed port. Synchronously add 20 g of modified ABS resin, 5 g of core-shell methyl methacrylate-butadiene-styrene polymer, and 4 g of the premix prepared in step S1 through the side feed port. The feeding zone is at 50 °C, the polycarbonate melting zone (zones 1 - 3) is at 255 - 260 °C, the modified ABS resin and core-shell methyl methacrylate-butadiene-styrene polymer zone (zones 4 - 5) is at 240 - 245 °C, the phosphorus-nitrogen synergistic flame retardant and premix zone (zones 6 - 7) is at 220 - 230 °C, and the die head is at 210 °C. The screw speed is 300 r / min, the torque is controlled at 60 - 70%, and vacuum exhaust is started at -0.08 MPa. After cutting into 2 - 3 mm pellets by water cooling at 25 °C, centrifuging, and screening with a 10 - 20 mesh sieve for standby, the blended pellets are obtained;

[0065] S3. Add the blended pellets into a servo-electric injection molding machine, set the melt temperature at 250 °C, the mold temperature at 85 °C, the injection pressure at 80 MPa, the holding pressure time at 20 s, and the cooling time at 30 s. After injection molding, demold, place it in a forced convection oven for annealing at 80 °C for 2 h, and then treat it with a 40 kHz atmospheric pressure plasma processor for 30 s, with a power of 100 W, an Ar / O2 mixed gas, and a pole spacing of 5 mm to obtain a PC / ABS composite material with stress resistance and anti-coating lifting. Example 3

[0066] A preparation method of a PC / ABS composite material with stress resistance and anti-coating lifting is as follows:

[0067] 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 in a 11.4 mL ethanol solution of 10% mass fraction of silane coupling agent KH550 at a spraying speed of 2 mL / min, mix for 3 min, discharge and let stand for 15 min, and then let stand in a fume hood with an air flow rate of 0.5 m / s for 24 h to obtain a premix;

[0068] S2. Add 65 g of polycarbonate (PC), 10 g of phosphorus-nitrogen synergistic flame retardant, 0.5 g of zinc phenylphosphate, and 0.5 g of bismaleimide into a co-rotating twin-screw extruder through the main feed port. Synchronously add 25 g of modified ABS resin, 8 g of core-shell methyl methacrylate-butadiene-styrene polymer, and 7 g of the premix prepared in step S1 through the side feed port. The feeding zone is at 50 °C, the polycarbonate melting zone (zones 1 - 3) is at 255 - 260 °C, the modified ABS resin and core-shell methyl methacrylate-butadiene-styrene polymer zone (zones 4 - 5) is at 240 - 245 °C, the phosphorus-nitrogen synergistic flame retardant and premix zone (zones 6 - 7) is at 220 - 230 °C, and the die head is at 210 °C. The screw speed is 300 r / min, the torque is controlled at 60 - 70%, and vacuum exhaust is started under -0.08 MPa. Cut into 2 - 3 mm pellets by water cooling at 25 °C, centrifuge, and sieve with 10 - 20 meshes for standby to obtain the blended pellets;

[0069] S3. Add the blended pellets into a servo-electric injection molding machine, set the melt temperature at 250 °C, the mold temperature at 85 °C, the injection pressure at 80 MPa, the holding pressure time at 20 s, and the cooling time at 30 s. Demold after injection molding, place in a forced convection oven for annealing at 80 °C for 2 h, and treat with a 40 kHz atmospheric pressure plasma processor for 30 s, with a power of 100 W, an Ar / O2 mixed gas, and a pole pitch of 5 mm to obtain the PC / ABS composite material with stress resistance and anti-coating lifting. Example 4

[0070] A preparation method of a PC / ABS composite material with stress resistance and anti-coating lifting is as follows:

[0071] 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 into 6.5 mL of a 10% silane coupling agent KH550 / ethanol solution at a spraying speed of 2 mL / min, mix for 3 min, discharge and let stand for 15 min, and let stand in a fume hood with an air flow rate of 0.5 m / s for 24 h to obtain the premix;

[0072] S2. Add 61.3 g of polycarbonate (PC), 8.5 g of a phosphorus-nitrogen synergistic flame retardant, 0.35 g of zinc phenylphosphate, and 0.35 g of bismaleimide into a co-rotating twin-screw extruder through the main feed port. Synchronously add 21.3 g of modified ABS resin, 5.8 g of core-shell methyl methacrylate-butadiene-styrene polymer, and 4.8 g of the premix prepared in step S1 through the side feed port. The feeding zone is at 50 °C, the polycarbonate melting zone (zones 1 - 3) is at 255 - 260 °C, the modified ABS resin and core-shell methyl methacrylate-butadiene-styrene polymer zone (zones 4 - 5) is at 240 - 245 °C, the phosphorus-nitrogen synergistic flame retardant and premix zone (zones 6 - 7) is at 220 - 230 °C, and the die head is at 210 °C. The screw speed is 300 r / min, the torque is controlled at 60 - 70%, and vacuum exhaust is started under -0.08 MPa. Cut into 2 - 3 mm pellets by water cooling at 25 °C, centrifuge, and sieve with 10 - 20 meshes for standby to obtain the blended pellets;

[0073] S3. Add the blended pellets into a servo-electric injection molding machine. Set the melt temperature at 250 °C, the mold temperature at 85 °C, the injection pressure at 80 MPa, the holding pressure time at 20 s, and the cooling time at 30 s. Demold after injection molding, place in a forced convection oven for annealing at 80 °C for 2 h, and treat with a 40 kHz atmospheric pressure plasma processor for 30 s, with a power of 100 W, an Ar / O2 mixed gas, and a pole spacing of 5 mm to obtain a PC / ABS composite material with stress resistance and anti-coating lifting. Example 5

[0074] A preparation method of a PC / ABS composite material with stress resistance and anti-coating lifting is as follows:

[0075] 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 into 8.9 mL of a 10% mass fraction silane coupling agent KH550 / ethanol solution at a spraying speed of 2 mL / min, mix for 3 min, discharge and let stand for 15 min, and let stand in a fume hood with an air flow rate of 0.5 m / s for 24 h to obtain the premix;

[0076] S2. Add 63.8 g of polycarbonate (PC), 9.5 g of a phosphorus-nitrogen synergistic flame retardant, 0.45 g of zinc phenylphosphate, and 0.45 g of bismaleimide into a co-rotating twin-screw extruder through the main feed port. Synchronously add 22.8 g of modified ABS resin, 7.3 g of core-shell methyl methacrylate-butadiene-styrene polymer, and 6.3 g of the premix prepared in step S1 through the side feed port. The feeding zone is at 50 °C, the polycarbonate melting zone (zones 1 - 3) is at 255 - 260 °C, the modified ABS resin and core-shell methyl methacrylate-butadiene-styrene polymer zone (zones 4 - 5) is at 240 - 245 °C, the phosphorus-nitrogen synergistic flame retardant and premix zone (zones 6 - 7) is at 220 - 230 °C, and the die head is at 210 °C. The screw speed is 300 r / min, the torque is controlled at 60 - 70%, and vacuum exhaust is started under -0.08 MPa. Cut into 2 - 3 mm pellets by water cooling at 25 °C, centrifuge, and sieve with 10 - 20 meshes for standby to obtain the blended pellets;

[0077] S3. Add the blended pellets into a servo-electric injection molding machine. Set the melt temperature at 250 °C, the mold temperature at 85 °C, the injection pressure at 80 MPa, the holding pressure time at 20 s, and the cooling time at 30 s. Demold after injection molding and anneal in a forced convection oven at 80 °C for 2 h, and then treat with a 40 kHz atmospheric pressure plasma processor for 30 s, with a power of 100 W, an Ar / O2 mixed gas, and a pole pitch of 5 mm to obtain the PC / ABS composite material with stress resistance and anti-coating lifting.

[0078] Comparative Example 1

[0079] A preparation method of a PC / ABS composite material with stress resistance and anti-coating lifting is as follows:

[0080] 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 into an 8.6 mL ethanol solution of 10% mass fraction of silane coupling agent KH550 at a spraying speed of 2 mL / min, mix for 3 min, discharge and let stand for 15 min, and then let stand in a fume hood with an air flow rate of 0.5 m / s for 24 h to obtain the premix;

[0081] S2. Add 62.5 g of polycarbonate (PC), 9 g of phosphorus-nitrogen synergistic flame retardant, 0.4 g of zinc phenylphosphate, and 0.4 g of bismaleimide into a co-rotating twin-screw extruder through the main feeding port. Synchronously add 22.5 g of ABS resin, 6.5 g of core-shell methyl methacrylate-butadiene-styrene polymer, and 5.5 g of the premix prepared in step S1 through the side feeding port. The feeding zone is at 50 °C, the polycarbonate melting zone (zones 1 - 3) is at 255 - 260 °C, the modified ABS resin and core-shell methyl methacrylate-butadiene-styrene polymer zone (zones 4 - 5) is at 240 - 245 °C, the phosphorus-nitrogen synergistic flame retardant and premix zone (zones 6 - 7) is at 220 - 230 °C, and the die head is at 210 °C. The screw speed is 300 r / min, the torque is controlled at 60 - 70%. Turn on the vacuum exhaust at -0.08 MPa, cool with water at 25 °C and cut into particles of 2 - 3 mm, centrifuge, and screen with 10 - 20 meshes for standby to obtain the blended pellets;

[0082] S3. Add the blended pellets into a servo-electric injection molding machine, set the melt temperature at 250 °C, the mold temperature at 85 °C, the injection pressure at 80 MPa, the holding pressure time at 20 s, and the cooling time at 30 s. Demold after injection molding, place in a forced convection oven and anneal at 80 °C for 2 h, and treat with a 40 kHz atmospheric pressure plasma processor for 30 s, with a power of 100 W, an Ar / O2 mixed gas, and a pole pitch of 5 mm to obtain a PC / ABS composite material with stress resistance and anti-coating lifting.

[0083] The difference between this comparative example and Example 1 is that unmodified ABS resin (acrylonitrile-butadiene-styrene copolymer) is used instead of modified ABS resin.

[0084] Comparative Example 2

[0085] A preparation method of a PC / ABS composite material with stress resistance and anti-coating lifting is as follows:

[0086] 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 into 8.6 mL of a 10% mass fraction silane coupling agent KH550 / ethanol solution at a spraying speed of 2 mL / min, mix for 3 min, discharge and let stand for 15 min, and let stand in a fume hood with an air flow rate of 0.5 m / s for 24 h to obtain the premix;

[0087] 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;

[0088] 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. After injection molding, demold the machine and place it in a forced convection oven for annealing at 80°C for 2h. Treat it with a 40kHz atmospheric pressure plasma processor for 30s, with a power of 100W, an Ar / O2 mixed gas, and an inter-electrode spacing of 5mm to obtain a stress-resistant and anti-coating bottoming PC / ABS composite material.

[0089] 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.

[0090] test:

[0091] 1. Stress resistance

[0092] Environmental stress cracking resistance: GB / T 43316.2-2023 Determination of environmental stress cracking resistance (ESC) of plastics Part 2: Constant tensile load method

[0093] Creep amount: GB / T 2567-2021 Test method for properties of resin castings

[0094] 2. Prevent coating from biting the bottom

[0095] 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;

[0096] Solvent resistance: GB / T 11547-2008 Determination of resistance of plastics to liquid chemical reagents

[0097] III. Flame Retardancy Performance

[0098] "Determination of Flammability of Plastics - Horizontal and Vertical Methods" (GB / T 2408 - 2021)

[0099] IV. Mechanical Properties

[0100] Impact Resistance: "Test Method for Impact Resistance of Plastics" (ASTM D256 - 97)

[0101] Flexural Property: "Determination of Flexural Properties of Plastics" (GB / T 9341 - 2008)

[0102] Tensile Property: "Determination of Tensile Properties of Plastics - Part 1: General Principles" (GB / T 1040.1 - 2018)

[0103] V. Frost - Thaw Cycle Resistance (Flexural Modulus Retention Rate)

[0104] Flexural Modulus: "Determination of Flexural Properties of Plastics" (GB / T 9341 - 2008)

[0105] Single Frost - Thaw Cycle: Spray and Immersion in Water for 1 h at a water temperature of 15 ± 5°C and a water flow rate of 1.0 - 1.5 L / (m²·min); Keep at a surface temperature of 20 ± 5°C and a humidity of ≥ 80% for 1 h for constant temperature and humidity control; Lower the surface temperature to - 20 ± 5°C (cool to the target temperature in 1 h) and freeze at low temperature for 5 h; Raise the surface temperature to 20 ± 5°C and thaw with a humidity of ≥ 80% for 1 h;

[0106] Repeat the cycle 12 times;

[0107] Flexural Property Retention Rate = E 冻融循环后 / E 初始 × 100%

[0108] VI. High - Temperature Stability (Tensile Strength Retention Rate)

[0109] "Test Method for Thermal Aging of Plastics" (GB / T 7141 - 2008)

[0110] For specimens with a nominal thickness of 0.3 ± 0.01 mm, test temperature: 120 - 150°C, time period: 500 h, air change rate: 10 ± 2 times / h;

[0111] Tensile Strength Retention Rate = σ 老化后 / σ 初始 × 100%

[0112] VII. Result Summary

[0113]

[0114] As can be seen from Table 2, the PC / ABS composite materials with stress resistance and anti-priming properties prepared in Examples 1-5 have excellent mechanical properties, flame retardancy, stress resistance, anti-priming ability, freeze-thaw cycle resistance and high temperature stability.

[0115] Although the embodiments of the present invention have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

[0116] 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 connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0117] The above content is only an example and illustration of the present invention. Those skilled in the art of the present technology can make various modifications or supplements to the specific embodiments described or use similar methods to substitute, as long as they do not deviate from the invention or exceed the scope defined by the claims of this patent, they should all belong to the protection scope of the present invention.

Claims

1. A PC / ABS composite material for resisting stress and preventing paint biting, characterized in that: Comprising the following raw material components by weight parts: 60 - 65 parts of polycarbonate; 20 - 25 parts of modified ABS resin; 5 - 8 parts of core - shell methyl methacrylate - butadiene - styrene polymer; 3 - 5 parts of fluorinated nano - silica; 0.5 - 1 part of fluorinated carbon nanotubes; 8 - 10 parts of phosphorus - nitrogen synergistic flame retardant; 0.3 - 0.5 part of zinc phenylphosphate; 0.3 - 0.5 part of bismaleimide; 0.5 - 1 part of silane coupling agent KH550; The preparation of the modified ABS resin is as follows: A1. Ozone - oxidize acrylonitrile - butadiene - styrene block copolymer with ozone concentration of 50 - 100 ppm, temperature of 25 - 40 °C for 1 - 3 h, transfer it to water with temperature of 40 - 60 °C and 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 sulfate solution, add styrene, diisocyanate and glycidyl methacrylate into the sodium dodecyl sulfate solution and mix. Stir - react at 25 °C with a rotation speed of 500 r / min for 10 - 15 min. Transfer the mixture to a high - pressure homogenizer, circulate and emulsify 3 times under a pressure of 60 MPa, let it stand at 25 °C for 30 min, and adjust the pH value to 6.5 - 7 to obtain a monomer pre - emulsion; A3. Under a nitrogen atmosphere, add the ABS particles into the reaction kettle, heat up to 75 °C, and drop - add part of the monomer pre - emulsion and part of the potassium persulfate solution prepared in step A1 at a rate of 0.5 mL / min, stir - react at a rotation speed of 200 r / min for 40 - 80 min to obtain a seed polymerization solution; A4. Heat up the reaction kettle to 80 °C, add the remaining monomer pre - emulsion and the remaining potassium persulfate solution in 3 - 4 portions under the stirring condition of a rotation speed of 150 r / min, with an interval of 30 min between each batch. After all are added, continuously stir - react for 3 - 4 h to obtain an emulsion; A5. Heat up the reaction kettle to 60 °C, add 10% calcium chloride solution into the emulsion, stir - react at a rotation speed of 200 r / min for 30 min, centrifuge at a rotation speed of 3000 r / min for 10 - 12 min, filter, wash 3 times with 60 °C hot water, and dry - treat with a spray drying tower to obtain granular modified ABS resin; The preparation steps of the fluorinated nano - silica are as follows: Vacuum - dry nano - silica at 120 °C for 4 h, disperse it in absolute ethanol, add perfluorooctyltriethoxysilane, reflux at 80 °C for 6 h, centrifuge, filter, wash until neutral, and dry at 80 °C to obtain fluorinated nano - silica.

2. The PC / ABS composite material for resisting stress and preventing paint biting according to claim 1, wherein: In step A2, the mass ratio of the sodium dodecyl sulfate solution, styrene, diisocyanate and glycidyl methacrylate is (270 - 310):(40 - 50):(13.5 - 16.5):(9 - 11); the sodium dodecyl sulfate solution is prepared from sodium dodecyl sulfate and deionized water, and the mass ratio of sodium dodecyl sulfate to deionized water is 1:(100 - 150).

3. The PC / ABS composite material for resisting stress and preventing paint biting according to claim 1, wherein: 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 PC / ABS composite material for resisting stress and preventing paint biting 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 potassium persulfate to deionized water is 3:(6 - 8).

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

1.

6. The PC / ABS composite material for resisting stress and preventing paint biting according to claim 1, wherein: 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: the inlet temperature is 180 °C, the outlet temperature is 80 °C, the feeding rate is 20 - 30 kg / h, and the rotation speed of the atomization disk is 6000 - 10000 r / min; the obtained granular modified ABS resin has a particle size of 1 - 3 mm.

7. An anti-stress and anti-priming 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. An anti-stress and anti-priming 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 triphenyl phosphate to melamine cyanurate is 6:

4.

9. A preparation method of a PC / ABS composite material with stress resistance and anti-coating biting bottom as described in any one of claims 1 - 8 is as follows: S1. Add fluorinated nano-silica and fluorinated carbon nanotubes to a dry mixer, dry mix for 2 - 3 min, spray in a 10% silane coupling agent KH550 / ethanol solution at a spray speed of 2 mL / min, mix for 3 - 5 min, discharge and let stand for 15 - 20 min, and let stand in a fume hood with an air flow rate of 0.5 - 1 m / s for 24 h to obtain a premix; The dosage 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. Add polycarbonate, phosphorus-nitrogen synergistic flame retardant, phenyl zinc phosphate, and bismaleimide through the main feeding port to a co-rotating twin-screw extruder, and synchronously add the modified ABS resin, the core-shell methyl methacrylate-butadiene-styrene polymer and the premix prepared in the step S1 through the side feeding port. Set the temperature at 50 - 260 °C, the screw speed at 300 r / min, control the torque at 60 - 70%, start vacuum exhaust at -0.08 MPa, and pelletize, centrifuge and screen with water cooling at 25 °C to obtain a blended pellet; 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 the 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 to a servo-electric injection molding machine, set the melt temperature at 250 °C, the mold temperature at 85 °C, the injection pressure at 80 MPa, the holding pressure time at 20 s, and the cooling time at 30 s. After injection molding, demold the product and anneal it in a forced convection oven at 80 °C for 2 h, and then treat it with a 40 kHz atmospheric pressure plasma processor for 30 - 40 s to obtain a PC / ABS composite material with anti-stress and anti-paint lifting properties.

10. The preparation method of a PC / ABS composite material for resisting stress and preventing paint from biting the substrate according to claim 9, characterized in that: In step S3, the parameters of the atmospheric pressure plasma processor are set as follows: power 100 W, Ar / O2 mixed gas, and the electrode spacing 5 mm.

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