PC / ABS composite material and preparation method thereof

Abstract

The invention belongs to the technical field of automobile materials, and discloses a PC / ABS composite material and a preparation method thereof, the PC / ABS composite material comprises the following components by weight: 40-80 parts of polycarbonate resin, 10-40 parts of an acrylonitrile-butadiene-styrene copolymer, 2-10 parts of a methyl methacrylate-butadiene-styrene copolymer, 0.5-5 parts of an odor adsorbent, 0.1-1 part of an antioxidant, and 0.2-1.5 parts of a lubricant. The polycarbonate resin and the acrylonitrile-butadiene-styrene copolymer are synergistically combined, the methyl methacrylate-butadiene-styrene copolymer is introduced, and the synergistic effect of the porous odor adsorbent, the antioxidant and the lubricant is matched, so that the mechanical property and the heat resistance are maintained, and meanwhile, the mechanical property and the heat resistance are improved. The release amount and the peculiar smell intensity of small molecule volatile matters in the processing and using processes of the material are reduced, and the long-term stability of the volatile release performance is enhanced.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of automobile materials, and particularly relates to a PC / ABS composite material and a preparation method thereof. BACKGROUND

[0002] Related composite materials for automobile interiors are modified by blending to improve their mechanical properties and processing characteristics, but it is often difficult to meet the requirements of low odor, low VOC release and high mechanical properties, and poor compatibility of components can easily lead to phase separation, resulting in high volatile organic compound release and poor odor performance of the material, and performance degradation due to heat and humidity aging during long-term use. SUMMARY

[0003] The purpose of the present application is to provide a PC / ABS composite material and a preparation method thereof, by using a synergistic combination of polycarbonate resin and acrylonitrile-butadiene-styrene copolymer, and introducing methyl methacrylate-butadiene-styrene copolymer as a toughening agent, and a multi-component synergistic effect of a porous odor adsorbent, an antioxidant and a lubricant, so that the composite material can maintain mechanical properties and heat resistance while reducing the release of small molecule volatile substances and odor intensity during processing and use. The preparation method of the present application eliminates the influence of moisture, degradation products and residual monomers during processing by multi-stage premixing, multi-stage vacuum devolatilization, synergistic control of melt temperature and residence time, and addition of an anti-hydrolysis agent, to inhibit the generation of odor substances and enhance the long-term stability of the volatile release performance of the composite material.

[0004] The specific scheme content is as follows:

[0005] A PC / ABS composite material, by weight, each component includes: polycarbonate resin 40-80 parts, acrylonitrile-butadiene-styrene copolymer 10-40 parts, methyl methacrylate-butadiene-styrene copolymer 2-10 parts, odor adsorbent 0.5-5 parts, antioxidant 0.1-1 parts, lubricant 0.2-1.5 parts, and the weight ratio of polycarbonate resin to acrylonitrile-butadiene-styrene copolymer is 1.5:1~4:1.

[0006] Further, the odor adsorbent is a composite adsorbent composed of microporous zeolite molecular sieve and mesoporous silica in a weight ratio of 1:1~3:1 after surface modification treatment.

[0007] Further, the polycarbonate resin is a low-volatility bisphenol A polycarbonate with a weight average molecular weight of 20000~30000, and the butadiene content in the acrylonitrile-butadiene-styrene copolymer is 10-20wt%.

[0008] Further, the antioxidant is tetra[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid]pentaerythritol ester or tris(2,4-di-tert-butylphenyl)phosphite.

[0009] Further, the lubricant is at least one of pentaerythritol stearate and ethylene bis-stearamide.

[0010] A preparation method of a PC / ABS composite material, for preparing the PC / ABS composite material, the steps comprising:

[0011] S1, preparing raw materials: preparing each raw material according to the ratio;

[0012] S2, pre-drying: blowing dry the polycarbonate resin at 110-130°C for 3-5 hours, and vacuum drying the odor adsorbent at 100-120°C for 2-4 hours;

[0013] S3, pre-mixing: adding the dried polycarbonate resin, acrylonitrile-butadiene-styrene copolymer, methyl methacrylate-butadiene-styrene copolymer, antioxidant and lubricant into a high-speed mixer, mixing at a speed of 300-600 rpm for 3-8 minutes to obtain a premix;

[0014] S4, melt blending and extrusion: adding the premix obtained in step S3 and the dried odor adsorbent into a twin-screw extruder through the main feeding port, melt mixing, extruding, drawing, cooling and pelletizing at a processing temperature of 220-260°C and a screw speed of 200-300 rpm to obtain a composite material;

[0015] S5, post-treatment: drying and standing the particles obtained in step S4 by hot air.

[0016] Further, in step S1, the preparation process of the surface-modified microporous zeolite molecular sieve is as follows: first, vacuum drying the microporous zeolite molecular sieve at 100-120°C for 2-4 hours to remove adsorbed water, then dispersing it in a solution prepared by mixing ethanol and deionized water at a volume ratio of 3:1, slowly adding γ-aminopropyltriethoxysilane accounting for 1.5%-2.5% of the mass of the zeolite under a constant temperature water bath at 60°C and mechanical stirring, and continuing the reaction for 4-6 hours; after the reaction is completed, removing the unreacted γ-aminopropyltriethoxysilane by suction filtration and ethanol washing three times, and finally vacuum drying the filter cake at 110°C for 6 hours to obtain a modified zeolite molecular sieve grafted with an aminopropyl functional group on the surface;

[0017] Furthermore, the dried polycarbonate resin, acrylonitrile-butadiene-styrene copolymer, methyl methacrylate-butadiene-styrene copolymer and antioxidant are first added to a high-speed mixer and mixed at 300-400 rpm for 3-5 minutes. Then, the lubricant is added and the mixture is continued to be mixed at 500-600 rpm for 1-2 minutes.

[0018] Furthermore, in step S4, the extrusion process includes at least two vacuum devouring sections, with the vacuum level controlled at -0.08 MPa to -0.095 MPa, controlling the melt extrusion process so that the melt temperature does not exceed 260°C, and the average residence time of the material in the extruder is 40-60 seconds. An anti-hydrolysis agent of 0.1%-0.5% of the total weight of the premix is ​​also added, wherein the anti-hydrolysis agent is polycarbodiimide, and the anti-hydrolysis agent is added in the middle of the melting section.

[0019] Furthermore, in step S5, the hot air drying temperature is 85-95℃, and the settling time is 4-6 hours.

[0020] Compared with the prior art, the present invention has the following advantages:

[0021] 1. This invention utilizes a synergistic combination of polycarbonate resin and acrylonitrile-butadiene-styrene copolymer, and introduces methyl methacrylate-butadiene-styrene copolymer as a toughening agent, along with the synergistic effect of porous odor adsorbent, antioxidant, and lubricant, thereby achieving the goal of reducing the release of small molecule volatiles and odor intensity during processing and use of the composite material while maintaining its mechanical properties and heat resistance.

[0022] 2. In this invention, a composite adsorbent is preferably made by combining surface-modified microporous zeolite molecular sieves and mesoporous silica in a specific ratio. By controlling the weight ratio of polycarbonate resin to acrylonitrile-butadiene-styrene copolymer, both the compatibility of the two phases is ensured to avoid phase separation, and a broad-spectrum adsorption of polar small molecules and hydrocarbon macromolecules is achieved. This can improve the odor suppression ability and VOC control performance of the composite material.

[0023] 3. The preparation method of the present invention eliminates the influence of moisture, degradation products and residual monomers during processing by multi-stage premixing, multi-stage vacuum devolatilization, synergistic control of melt temperature and residence time, and addition of anti-hydrolysis agent, thereby achieving the effect of inhibiting the generation of odor substances and enhancing the long-term stability of the volatile release performance of composite materials. Detailed Implementation

[0024] The technical solutions in the embodiments of the present invention will be described in detail below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] This invention proposes a PC / ABS composite material, which is a low-odor, low-VOC-emission PC / ABS composite material for automotive interiors. By weight, the components include: 40-80 parts of polycarbonate resin, 10-40 parts of acrylonitrile-butadiene-styrene copolymer, 2-10 parts of methyl methacrylate-butadiene-styrene copolymer, 0.5-5 parts of odor absorber, 0.1-1 parts of antioxidant, and 0.2-1.5 parts of lubricant.

[0026] By adopting the above technical solutions, polycarbonate resin, as the matrix, provides the required heat resistance and impact strength of the material. At the same time, acrylonitrile-butadiene-styrene copolymer improves the processing fluidity of polycarbonate resin, thereby reducing costs. Methyl methacrylate-butadiene-styrene copolymer, as a polymeric toughening agent, induces crazes and shear bands through its core-shell structure, thereby improving the toughness of the composite material. Furthermore, the odor adsorbent physically adsorbs small volatile molecules released during processing and use through its porous structure, while the antioxidant inhibits the thermo-oxidative degradation of the material under high-temperature processing by capturing free radicals and decomposing hydrogen peroxide. The lubricant reduces friction between polymer molecular chains and with the metal surface of the equipment during melt processing. Thus, the synergistic effect reduces the odor level and total volatile organic compound release of the material while ensuring the basic mechanical properties of the material.

[0027] The weight ratio of polycarbonate resin to acrylonitrile-butadiene-styrene copolymer is 1.5:1 to 4:1.

[0028] The odor adsorbent is a composite adsorbent composed of surface-modified microporous zeolite molecular sieve and mesoporous silica in a weight ratio of 1:1 to 3:1.

[0029] By adopting the above technical solution and controlling the ratio of polycarbonate resin to acrylonitrile-butadiene-styrene copolymer within this range, the composite material can retain the mechanical properties and heat resistance of the polycarbonate resin itself, and obtain the high processing performance brought by acrylonitrile-butadiene-styrene copolymer, avoiding phase separation and performance degradation caused by poor compatibility between the two phases. Furthermore, the use of surface-modified zeolite molecular sieves and mesoporous silica for compounding allows the surface modification to enhance the interfacial compatibility between the adsorbent and the polymer matrix and prevent agglomeration. Microporous zeolite molecular sieves adsorb small-molecule polar volatiles, while mesoporous silica has a strong adsorption capacity for larger-molecule hydrocarbons. The combination of the two achieves complementarity and synergy of adsorption spectra, thereby comprehensively and efficiently reducing the odor of the material.

[0030] The polycarbonate resin is a low-volatility bisphenol A type polycarbonate with a weight average molecular weight of 20,000 to 30,000, and the butadiene content in the acrylonitrile-butadiene-styrene copolymer is 10-20 wt%.

[0031] By adopting the above technical solutions, the polycarbonate resin in this molecular weight range has a moderate melt viscosity, which can ensure both high processability and high mechanical strength. The low volatility level means that the resin itself has a low content of small molecules such as residual monomers and oligomers, further reducing the source of VOCs. By controlling the butadiene content in the acrylonitrile-butadiene-styrene copolymer to 10-20wt%, the rubber phase particle size and distribution in the system within this content range cause energy dissipation, thereby achieving efficient toughening, while avoiding the risk of oxidative degradation and unpleasant odor caused by excessive butadiene content.

[0032] The antioxidant is pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] or tris(2,4-di-tert-butylphenyl)phosphite.

[0033] The lubricant is at least one of pentaerythritol stearate and ethylene bis-stearamide.

[0034] By adopting the above technical solution, pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] can capture free radicals generated during oxidation, while tris(2,4-di-tert-butylphenyl)phosphite can decompose hydrogen peroxide. Both can delay the thermal oxidative degradation of the material during melt extrusion, which leads to the generation of small molecule aldehydes and ketones with irritating odors, thereby inhibiting the generation of odor substances. Pentaerythritol stearate and ethylene bis-stearamide, as lubricants, can reduce the melt viscosity and the adhesion between the melt and the screw and barrel, reduce local overheating degradation caused by excessive shear heat, and promote uniform mixing of materials, which helps to disperse components such as odor adsorbents.

[0035] This invention also provides a method for preparing a PC / ABS composite material, comprising the following steps:

[0036] S1. Prepare raw materials: Prepare each raw material according to the proportions;

[0037] S2. Pre-drying: Dry the polycarbonate resin in a forced-air dryer at 110-130℃ for 3-5 hours, and vacuum dry the odor absorbent at 100-120℃ for 2-4 hours.

[0038] S3. Premixing: Add the dried polycarbonate resin, acrylonitrile-butadiene-styrene copolymer, methyl methacrylate-butadiene-styrene copolymer, antioxidant and lubricant into a high-speed mixer and mix at 300-600 rpm for 3-8 minutes to obtain the premix.

[0039] S4. Melt blending and extrusion: The premix obtained in step S3 and the dried odor adsorbent are fed into a twin-screw extruder through the main feed port. The mixture is melt-blended, extruded, drawn into strands, cooled, and pelletized at a processing temperature of 220-260℃ and a screw speed of 200-300rpm to obtain a composite material.

[0040] S5. Post-processing: The particles obtained in step S4 are dried by hot air and then left to stand.

[0041] This invention employs the technical solutions described in steps S1 to S5 above. Through raw material pretreatment, the moisture content in the base resin and adsorbent is reduced, preventing VOC generation through hydrolysis and degradation during high-temperature processing. The premixing process initially disperses trace additives within the resin matrix, laying the foundation for uniform dispersion in subsequent melt blending. Simultaneously, during melt blending extrusion, the strong shearing and kneading action provided by the twin-screw extruder disperses and mixes the components, while high temperature melts and plasticizes the polymer, uniformly coating and fixing the adsorbent and other components within the matrix. Subsequent hot air drying and settling remove trace amounts of moisture adsorbed on the particle surface and allow the extremely small molecules remaining within the particles to slowly diffuse and escape, thereby stabilizing the material's volatile release level.

[0042] In step S3, the premixing process is carried out in two steps: first, all components except the lubricant are mixed at 300-400 rpm for 3-5 minutes, and then the lubricant is added and the mixture is continued at 500-600 rpm for 1-2 minutes.

[0043] The above-mentioned technical solution is adopted in the premixing process. At medium speed, powdered additives such as antioxidants are initially adhered to the surface of resin particles to prevent dust from flying and improve the uniformity of mixing. Then, lubricant is added and mixed for a short time at a higher speed. This operation can avoid the lubricant from prematurely coating the surface of resin particles and hindering the dispersion of other additives, ensuring that all components are uniformly mixed, laying the foundation for micro-dispersion in the subsequent melt extrusion process.

[0044] In step S1, the preparation process of the surface-modified microporous zeolite molecular sieve is as follows: First, the microporous zeolite molecular sieve is vacuum dried at 100-120℃ for 2-4 hours to remove adsorbed water. Then, it is dispersed in a solution prepared by mixing ethanol and deionized water at a volume ratio of 3:1. Under constant temperature water bath at 60℃ and mechanical stirring, 1.5%-2.5% of γ-aminopropyltriethoxysilane by mass of zeolite is slowly added and the reaction is continued for 4-6 hours. After the reaction is completed, the unreacted γ-aminopropyltriethoxysilane is removed by filtration and washing with ethanol three times. Finally, the filter cake is vacuum dried at 110℃ for 6 hours to obtain the modified zeolite molecular sieve with aminopropyl functional groups grafted on its surface.

[0045] In step S4, the extrusion process includes at least two vacuum devouring sections, with the vacuum level controlled between -0.08 MPa and -0.095 MPa.

[0046] Multiple high-vacuum devolatilization sections are installed on the barrel of the twin-screw extruder. Their function is to continuously extract small molecule volatile substances such as water vapor, residual monomers, and degradation products contained in the melt during the melt blending process. Maintaining a high vacuum can reduce the partial pressure of volatiles and enhance the removal efficiency. This measure directly removes odors and VOCs from the melt.

[0047] In step S4, the melt extrusion process is controlled so that the melt temperature does not exceed 260°C and the average residence time of the material in the extruder is 40-60 seconds.

[0048] Controlling the upper limit of melt temperature is to prevent polycarbonate resin from undergoing thermal degradation. When the thermal stability threshold is exceeded, irritating odor substances such as phenol will be produced. At the same time, controlling the material residence time within a reasonable and short range reduces the time the material is in a high-temperature state, thereby inhibiting the occurrence of degradation side reactions such as thermal oxidation and hydrolysis. By controlling time and temperature in tandem, the new odor and VOCs introduced during processing can be reduced.

[0049] In step S4, an anti-hydrolysis agent of 0.1%-0.5% of the total weight of the premix is ​​added, wherein the anti-hydrolysis agent is polycarbodiimide, and the anti-hydrolysis agent is added in the middle of the melting section.

[0050] Polycarbodiimide anti-hydrolysis agents contain carbodiimide groups that can react with the terminal hydroxyl groups of polycarbonate chains and the carboxyl groups generated during hydrolysis. This reaction can terminate the hydrolysis chain reaction, prevent further decrease in molecular weight and the vicious cycle of carboxyl group-catalyzed accelerated hydrolysis, thereby improving the stability of composite materials in high temperature and high humidity environments and reducing VOCs generated by hydrolysis. At the same time, adding the anti-hydrolysis agent in the middle of the melting zone can avoid self-consumption or failure due to excessive residence time, ensuring its efficient function.

[0051] In step S5, the hot air drying temperature is 85-95℃, and the settling time is 4-6 hours.

[0052] After extrusion and pelletizing, the surface of the particles adsorbs trace amounts of moisture, and there may be processing stress and incompletely released volatile matter inside. Hot air drying at 85-95℃ can remove the surface adsorbed water without causing thermal deformation and adhesion of the resin particles. The subsequent static treatment provides a mild heat treatment process, which helps to remove residual stress and accelerates the slow diffusion and eventual escape of trace small molecules from the particles to the surface, so that the volatile release performance of the composite material reaches a stable state before leaving the factory.

[0053] The present invention will be further described below with reference to embodiments and comparative examples.

[0054] Example 1:

[0055] This embodiment provides a PC / ABS composite material, wherein the raw materials of each component, by weight, include:

[0056] 45 parts of polycarbonate resin,

[0057] 15 parts of acrylonitrile-butadiene-styrene copolymer

[0058] 3 parts of methyl methacrylate-butadiene-styrene copolymer

[0059] Odor absorbent 1.0 part,

[0060] Antioxidant 0.3 parts,

[0061] 0.5 parts lubricant;

[0062] The weight ratio of polycarbonate resin to acrylonitrile-butadiene-styrene copolymer is 3:1 (45 / 15=3); the odor adsorbent is a composite adsorbent composed of surface-modified microporous zeolite molecular sieve and mesoporous silica in a weight ratio of 1:1.

[0063] The polycarbonate resin is a low-volatility bisphenol A type polycarbonate with a weight average molecular weight of 20,000. The butadiene content in the acrylonitrile-butadiene-styrene copolymer is 10 wt%. The antioxidant is pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], and the lubricant is pentaerythritol stearate.

[0064] The preparation method of the above PC / ABS composite material is as follows:

[0065] S1. Prepare raw materials: Prepare each raw material according to the proportions;

[0066] S2. Pre-drying: Dry the polycarbonate resin at 110°C with forced air for 5 hours, and vacuum dry the odor absorbent at 100°C for 4 hours.

[0067] S3. Premixing: Add the dried polycarbonate resin, acrylonitrile-butadiene-styrene copolymer, methyl methacrylate-butadiene-styrene copolymer, antioxidant and lubricant into a high-speed mixer and mix at 300 rpm for 8 minutes to obtain a premix.

[0068] The premixing process is carried out in two steps: first, all components except the lubricant are mixed at 300 rpm for 5 minutes, and then the lubricant is added and mixed at 500 rpm for another 2 minutes.

[0069] S4. Melt blending and extrusion: The premix obtained in step S3 and the dried odor adsorbent are fed into a twin-screw extruder through the main feed port. The mixture is melt-blended, extruded, drawn into strands, cooled, and pelletized at a processing temperature of 220°C and a screw speed of 200 rpm to obtain a composite material.

[0070] The extrusion process includes two vacuum devouring sections with a vacuum level controlled at -0.08 MPa; the melt extrusion process is controlled to ensure that the melt temperature does not exceed 260°C and the average residence time of the material in the extruder is 60 seconds; polycarbodiimide, accounting for 0.1% of the total weight of the premix, is added as an anti-hydrolysis agent, and the anti-hydrolysis agent is added in the middle of the melting section through the side feed port;

[0071] S5. Post-processing: The particles obtained in step S4 are dried by hot air and then allowed to stand.

[0072] The hot air drying temperature is 85℃, and the settling time is 6 hours.

[0073] Example 2

[0074] This embodiment provides a PC / ABS composite material, wherein the raw materials of each component, by weight, include:

[0075] 75 parts of polycarbonate resin,

[0076] 35 parts of acrylonitrile-butadiene-styrene copolymer

[0077] 8 parts of methyl methacrylate-butadiene-styrene copolymer

[0078] Odor absorbent 4.0 parts,

[0079] Antioxidant 0.8 parts,

[0080] 1.2 parts lubricant;

[0081] The weight ratio of polycarbonate resin to acrylonitrile-butadiene-styrene copolymer is 75:35≈2.14:1; the odor adsorbent is a composite adsorbent composed of surface-modified microporous zeolite molecular sieve and mesoporous silica in a weight ratio of 3:1.

[0082] The polycarbonate resin is a low-volatility bisphenol A type polycarbonate with a weight average molecular weight of 30,000, and the butadiene content in the acrylonitrile-butadiene-styrene copolymer is 20wt%; the antioxidant is tris(2,4-di-tert-butylphenyl) phosphite, and the lubricant is ethylene bis-stearamide.

[0083] The preparation method of the above PC / ABS composite material is as follows:

[0084] S1. Prepare raw materials: Prepare each raw material according to the proportions;

[0085] S2. Pre-drying: Dry the polycarbonate resin in a forced-air dryer at 130°C for 3 hours, and vacuum dry the odor absorbent at 120°C for 2 hours.

[0086] S3. Premixing: Add the dried polycarbonate resin, acrylonitrile-butadiene-styrene copolymer, methyl methacrylate-butadiene-styrene copolymer, antioxidant and lubricant into a high-speed mixer and mix at 600 rpm for 3 minutes to obtain a premix.

[0087] The premixing process is carried out in two steps: first, all components except the lubricant are mixed at 400 rpm for 3 minutes, and then the lubricant is added and mixed at 600 rpm for 1 minute.

[0088] S4. Melt blending and extrusion: The premix obtained in step S3 and the dried odor adsorbent are fed into a twin-screw extruder through the main feed port. The mixture is melt-blended, extruded, drawn into strands, cooled, and pelletized at a processing temperature of 260°C and a screw speed of 300 rpm to obtain a composite material.

[0089] The extrusion process includes two vacuum devouring sections with a vacuum level controlled at -0.095 MPa; the melt extrusion process is controlled to ensure that the melt temperature does not exceed 260°C and the average residence time of the material in the extruder is 40 seconds; polycarbodiimide, accounting for 0.5% of the total weight of the premix, is added as an anti-hydrolysis agent, and the anti-hydrolysis agent is added in the middle of the melting section through the side feed port;

[0090] S5. Post-processing: The particles obtained in step S4 are dried by hot air and then allowed to stand.

[0091] The hot air drying temperature is 95℃, and the settling time is 4 hours.

[0092] Example 3

[0093] This embodiment provides a PC / ABS composite material, wherein the raw materials of each component, by weight, include:

[0094] 60 parts of polycarbonate resin

[0095] 25 parts of acrylonitrile-butadiene-styrene copolymer

[0096] 5 parts of methyl methacrylate-butadiene-styrene copolymer

[0097] Odor absorbent 2.5 parts,

[0098] 0.5 parts antioxidant,

[0099] 0.8 parts lubricant;

[0100] The weight ratio of polycarbonate resin to acrylonitrile-butadiene-styrene copolymer is 2.4:1 (60 / 25=2.4); the odor adsorbent is a composite adsorbent composed of surface-modified microporous zeolite molecular sieve and mesoporous silica in a weight ratio of 2:1.

[0101] The polycarbonate resin is a low-volatility bisphenol A type polycarbonate with a weight average molecular weight of 25,000, and the butadiene content in the acrylonitrile-butadiene-styrene copolymer is 15 wt%. The antioxidant is a compound composed of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] and tris(2,4-di-tert-butylphenyl) phosphite in a weight ratio of 1:1. The lubricant is a compound composed of pentaerythritol stearate and ethylene bis-stearamide in a weight ratio of 1:1.

[0102] The preparation method of the above PC / ABS composite material is as follows:

[0103] S1. Prepare raw materials: Prepare each raw material according to the proportions;

[0104] S2. Pre-drying: Dry the polycarbonate resin in a forced-air dryer at 120°C for 4 hours, and vacuum dry the odor absorbent at 110°C for 3 hours.

[0105] S3. Premixing: Add the dried polycarbonate resin, acrylonitrile-butadiene-styrene copolymer, methyl methacrylate-butadiene-styrene copolymer, antioxidant and lubricant into a high-speed mixer and mix at 450 rpm for 5 minutes to obtain a premix.

[0106] The premixing process is carried out in two steps: first, all components except the lubricant are mixed at 350 rpm for 4 minutes, and then the lubricant is added and the mixture is continued at 550 rpm for 1.5 minutes.

[0107] S4. Melt blending and extrusion: The premix obtained in step S3 and the dried odor adsorbent are fed into a twin-screw extruder through the main feed port. The mixture is melt-blended, extruded, drawn into strands, cooled, and pelletized at a processing temperature of 240°C and a screw speed of 250 rpm to obtain a composite material.

[0108] The extrusion process includes two vacuum devouring sections with a vacuum level controlled at -0.09 MPa; the melt extrusion process is controlled to ensure that the melt temperature does not exceed 260°C and the average residence time of the material in the extruder is 50 seconds; polycarbodiimide, accounting for 0.3% of the total weight of the premix, is added as an anti-hydrolysis agent, and the anti-hydrolysis agent is added in the middle of the melting section through the side feed port;

[0109] S5. Post-processing: The particles obtained in step S4 are dried by hot air and then allowed to stand.

[0110] The hot air drying temperature is 90℃, and the settling time is 5 hours.

[0111] Example 4

[0112] This embodiment provides a PC / ABS composite material, wherein the raw materials of each component, by weight, include:

[0113] 40 parts of polycarbonate resin

[0114] 26.7 parts of acrylonitrile-butadiene-styrene copolymer,

[0115] Two parts of methyl methacrylate-butadiene-styrene copolymer

[0116] Odor absorbent 0.5 parts,

[0117] 0.1 parts antioxidant,

[0118] 0.2 parts lubricant;

[0119] The weight ratio of polycarbonate resin to acrylonitrile-butadiene-styrene copolymer is 1.5:1 (40 / 26.7≈1.5); the odor adsorbent is a composite adsorbent composed of surface-modified microporous zeolite molecular sieve and mesoporous silica in a weight ratio of 1:1.

[0120] The polycarbonate resin is a low-volatility bisphenol A type polycarbonate with a weight average molecular weight of 20,000. The butadiene content in the acrylonitrile-butadiene-styrene copolymer is 10 wt%. The antioxidant is pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], and the lubricant is pentaerythritol stearate.

[0121] The preparation method of the above PC / ABS composite material is the same as that in Example 1.

[0122] Example 5

[0123] This embodiment provides a PC / ABS composite material, wherein the raw materials of each component, by weight, include:

[0124] 80 parts of polycarbonate resin

[0125] 20 parts of acrylonitrile-butadiene-styrene copolymer

[0126] 10 parts of methyl methacrylate-butadiene-styrene copolymer

[0127] 5 parts of odor absorbent

[0128] 1 part antioxidant

[0129] 1.5 parts lubricant;

[0130] The polycarbonate resin and acrylonitrile-butadiene-styrene copolymer are in a weight ratio of 4:1 (80 / 20=4); the odor adsorbent is a composite adsorbent composed of surface-modified microporous zeolite molecular sieve and mesoporous silica in a weight ratio of 3:1.

[0131] The polycarbonate resin is a low-volatility bisphenol A type polycarbonate with a weight average molecular weight of 30,000, and the butadiene content in the acrylonitrile-butadiene-styrene copolymer is 20wt%; the antioxidant is tris(2,4-di-tert-butylphenyl) phosphite, and the lubricant is ethylene bis-stearamide.

[0132] The preparation method of the above PC / ABS composite material is the same as that in Example 2.

[0133] Comparative Example 1

[0134] This comparative example is based on the content of Example 1, except that the amount of polycarbonate resin used is 35 parts and the amount of acrylonitrile-butadiene-styrene copolymer used is 25 parts, and the rest is the same as in Example 1.

[0135] Comparative Example 2

[0136] This comparative example is based on the content of Example 1, except that the butadiene content in the acrylonitrile-butadiene-styrene copolymer is 25wt%, and the rest is the same as in Example 1.

[0137] Comparative Example 3

[0138] This comparative example is based on the content of Example 1, except that the amount of methyl methacrylate-butadiene-styrene copolymer used is 1.5 parts, and the rest is the same as in Example 1.

[0139] Comparative Example 4

[0140] This comparative example refers to the content of Example 1, except that the odor adsorbent used is a microporous zeolite molecular sieve and mesoporous silica composite in the same weight ratio without surface modification treatment. The rest of the content is the same as in Example 1.

[0141] Comparative Example 5

[0142] This comparative example refers to the content of Example 1, except that a vacuum devolatilization section was not set in the melt blending extrusion process, and the rest is the same as Example 1.

[0143] Comparative Example 6

[0144] This comparative example is based on the content of Example 1, except that no polycarbodiimide anti-hydrolysis agent was added; otherwise, it is the same as Example 1.

[0145] Performance testing

[0146] The PC / ABS composite materials prepared in Examples 1-5 and Comparative Examples 1-6 were injection molded into specific specifications of specimens required for various performance tests under standard experimental conditions. All specimens were conditioned in a standard environment of 23°C and 50% relative humidity for no less than 24 hours before testing to ensure the uniformity of test conditions and the comparability of results.

[0147] Total volatile organic compound (TVOC) emission detection: The test was conducted in accordance with the international standard ISO12219-1. The sample of specified size was placed in a sampling bag of a specific volume and heated at 65°C for 2 hours. Gas samples were collected using a thermal desorption instrument and then qualitatively and quantitatively analyzed by gas chromatography-mass spectrometry (GC-MS).

[0148] Notched impact strength test of simply supported beam: The test is conducted in accordance with the international standard ISO179-1. A universal pendulum impact tester is used to impact the specimen with a standard size notch, and the energy value absorbed when the specimen breaks is recorded.

[0149] Melt mass flow rate test: The test was conducted in accordance with the international standard ISO1133. Under the specified temperature of 260℃ and load of 5.0kg, the mass of the melt passing through the standard die in 10 minutes was measured using a melt indexer. The final result is expressed as g / 10min.

[0150] Heat distortion temperature test: The test is conducted in accordance with the international standard ISO75-1. The standard sample is placed in a silicone oil bath and the temperature at which it reaches the standard deflection is measured under a heating rate of 2℃ / min and a bending stress of 1.80MPa. This temperature is the heat distortion temperature.

[0151] Volatile organic compound (VOC) release test after damp heat aging: The sample was placed in a constant temperature and humidity chamber at 85℃ and 85% relative humidity for 120 hours. Then, the total VOC release was tested according to the above ISO12219-2:2012 standard. The performance stability was evaluated by comparing the changes in data before and after aging.

[0152] Table 1 shows the performance test data for Examples 1-5 and Comparative Examples 1-6.

[0153]

[0154] As can be seen from Examples 1-5 and Comparative Example 1, and Table 1, maintaining the ratio of polycarbonate resin to acrylonitrile-butadiene-styrene copolymer within a certain range can ensure the compatibility of the two phases and avoid phase separation. This synergistic effect not only ensures that the material obtains high mechanical properties and high heat resistance, but also controls the release of volatile organic compounds, thereby improving the overall performance of the material.

[0155] As can be seen from Examples 1-5 and Comparative Example 2, and Table 1, controlling the rubber phase content in the acrylonitrile-butadiene-styrene copolymer within a certain range can achieve efficient toughening while suppressing the unpleasant odor caused by the oxidative degradation of the rubber phase, thereby improving the sensory quality and reliability of the material.

[0156] As can be seen from Examples 1-5 and Comparative Example 3 and Table 1, the addition of a certain amount of methyl methacrylate-butadiene-styrene copolymer toughening agent can ensure that the composite material induces shear bands, absorbs and dissipates energy when subjected to impact, thereby promoting the composite material to obtain high toughness and impact resistance.

[0157] As can be seen from Examples 1-5 and Comparative Example 4, and Table 1, surface modification of the microporous zeolite molecular sieve and mesoporous silica composite adsorbent enhances its interfacial compatibility and dispersion stability with the polymer matrix. This treatment synergistically captures volatiles of different polarities and molecular sizes through physical adsorption, thereby improving the material's odor purification ability and overall low volatility characteristics.

[0158] As can be seen from Examples 1-5 and Comparative Example 5 and Table 1, setting a high-vacuum devolatilization process in the melt blending extrusion process can remove small molecules such as water vapor, residual monomers and thermal degradation products contained in the melt in real time during the processing stage. This step reduces the generation and residue of odor and volatile organic compounds from the source, thereby obtaining a low-odor, low-VOC release product.

[0159] As can be seen from Examples 1-5 and Comparative Example 6, and Table 1, adding a polycarbodiimide anti-hydrolysis agent and adding it in the middle of the melting zone can terminate the hydrolytic chain reaction of polycarbonate. This measure enhances the chemical stability of the composite material under high temperature and high humidity conditions, thereby ensuring the long-term durability of the product's volatile release performance.

[0160] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

[0161] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A PC / ABS composite material, characterized in that, By weight, the components include: 40-80 parts polycarbonate resin, 10-40 parts acrylonitrile-butadiene-styrene copolymer, 2-10 parts methyl methacrylate-butadiene-styrene copolymer, 0.5-5 parts odor absorber, 0.1-1 part antioxidant, and 0.2-1.5 parts lubricant. The weight ratio of polycarbonate resin to acrylonitrile-butadiene-styrene copolymer is 1.5:1 to 4:

1.

2. The PC / ABS composite material according to claim 1, characterized in that, The odor adsorbent is a composite adsorbent composed of surface-modified microporous zeolite molecular sieve and mesoporous silica in a weight ratio of 1:1 to 3:

1.

3. The PC / ABS composite material according to claim 1, characterized in that, The polycarbonate resin is a low-volatility bisphenol A type polycarbonate with a weight average molecular weight of 20,000 to 30,000, and the butadiene content in the acrylonitrile-butadiene-styrene copolymer is 10-20 wt%.

4. The PC / ABS composite material according to claim 1, characterized in that, The antioxidant is at least one of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] and tris(2,4-di-tert-butylphenyl)phosphite.

5. The PC / ABS composite material according to claim 1, characterized in that, The lubricant is at least one of pentaerythritol stearate and ethylene bis-stearamide.

6. A method for preparing a PC / ABS composite material, characterized in that, The step for preparing the PC / ABS composite material as described in any one of claims 1-5 includes: S1. Prepare raw materials: Prepare each raw material according to the proportions; S2. Pre-drying: Dry the polycarbonate resin in a forced-air dryer at 110-130℃ for 3-5 hours, and vacuum dry the odor absorbent at 100-120℃ for 2-4 hours. S3. Premixing: Add the dried polycarbonate resin, acrylonitrile-butadiene-styrene copolymer, methyl methacrylate-butadiene-styrene copolymer, antioxidant and lubricant into a high-speed mixer and mix at 300-600 rpm for 3-8 minutes to obtain the premix. S4. Melt blending and extrusion: The premix obtained in step S3 and the dried odor adsorbent are fed into a twin-screw extruder through the main feed port. The mixture is melt-blended, extruded, drawn into strands, cooled, and pelletized at a processing temperature of 220-260℃ and a screw speed of 200-300rpm to obtain a composite material. S5. Post-processing: The particles obtained in step S4 are dried by hot air and then left to stand.

7. The method for preparing the PC / ABS composite material according to claim 6, characterized in that, In step S1, the preparation process of the surface-modified microporous zeolite molecular sieve is as follows: First, the microporous zeolite molecular sieve is vacuum dried at 100-120℃ for 2-4 hours to remove adsorbed water. Then, it is dispersed in a solution prepared by mixing ethanol and deionized water at a volume ratio of 3:

1. Under constant temperature water bath at 60℃ and mechanical stirring, 1.5%-2.5% of γ-aminopropyltriethoxysilane by mass of zeolite is slowly added and the reaction is continued for 4-6 hours. After the reaction is completed, the unreacted γ-aminopropyltriethoxysilane is removed by filtration and washing with ethanol three times. Finally, the filter cake is vacuum dried at 110℃ for 6 hours to obtain the modified zeolite molecular sieve with aminopropyl functional groups grafted on its surface.

8. The method for preparing PC / ABS composite material according to claim 6, characterized in that, In step S3, the dried polycarbonate resin, acrylonitrile-butadiene-styrene copolymer, methyl methacrylate-butadiene-styrene copolymer and antioxidant are first added to a high-speed mixer and mixed at 300-400 rpm for 3-5 minutes. Then, the lubricant is added and the mixture is continued to be mixed at 500-600 rpm for 1-2 minutes.

9. The method for preparing PC / ABS composite material according to claim 6, characterized in that, In step S4, the extrusion process includes at least two vacuum devouring sections, with the vacuum level controlled at -0.08MPa to -0.095MPa. The process of melt extrusion is controlled so that the melt temperature does not exceed 260°C and the average residence time of the material in the extruder is 40-60 seconds. An anti-hydrolysis agent of 0.1%-0.5% of the total weight of the premix is ​​also added, wherein the anti-hydrolysis agent is polycarbodiimide, and the anti-hydrolysis agent is added in the middle of the melt section.

10. The method for preparing the PC / ABS composite material according to claim 6, characterized in that, In step S5, the hot air drying temperature is 85-95℃, and the settling time is 4-6 hours.

Images