A modified pc / abs alloy and a method for producing the same

Abstract

This application belongs to the field of polymer materials technology, specifically disclosing a modified PC / ABS alloy and its preparation method. By weight, it comprises: polycarbonate: 50-80 parts; ABS resin: 15-40 parts; comb-shaped reactive compatibilizer: 3-8 parts; halogen-free flame retardant: 8-18 parts; nano-talc powder: 3-10 parts; core-shell toughening agent: 2-8 parts; antistatic agent: 0.5-3 parts; antioxidant: 0.2-0.8 parts; lubricant: 0.2-1.0 parts. The tensile strength (56.3-66.8 MPa), flexural strength (88.4-98.5 MPa), flexural modulus (2480-2780 MPa), and notched impact strength (23℃: 52.4-62.5 kJ / m) are also disclosed. 2 -30℃: 28.5~36.2kJ / m 2 Heat distortion temperature (110~125℃), limiting oxygen index (30.0~32.0%), flame retardant rating (V-0), and surface resistivity (5.2×10⁻⁶) are also specified. 9 ~2.5×10 10 In terms of Ω), it is better, and the high performance of PC / ABS alloy is achieved by using reactive compatibilizers, nano talc powder, phosphorus-nitrogen-silicon ternary synergistic flame retardant system, core-shell toughening agent and polymeric antistatic agent.

Description

Technical Field

[0001] This application relates to the field of polymer materials technology, and in particular to a modified PC / ABS alloy and its preparation method. Background Technology

[0002] Polycarbonate (PC) possesses excellent impact resistance, heat resistance, and dimensional stability, but it suffers from drawbacks such as high melt viscosity and poor resistance to stress cracking. Acrylonitrile-butadiene-styrene copolymer (ABS) exhibits good processing fluidity and chemical resistance. PC / ABS alloys combine the advantages of both, making them one of the most widely used engineering plastic alloys.

[0003] However, existing PC / ABS alloys still have the following technical problems:

[0004] First, poor compatibility. PC and ABS are thermodynamically partially compatible systems, and phase separation easily occurs after blending, leading to a decrease in mechanical properties. Existing linear compatibilizers (such as SMA and MBS) have limited compatibilization efficiency and are difficult to stably distribute at the interface between the two phases under shear.

[0005] Second, insufficient heat resistance. The introduction of ABS will reduce the heat distortion temperature of the alloy, especially under high temperature (>100℃) conditions, the mechanical properties will be significantly reduced, which limits its application in high-temperature environments such as automobile engine compartments and electronic appliances.

[0006] Third, the flame retardant properties are poor. PC itself has limited flame retardancy, while ABS is a flammable material. When the two are blended, the flame retardant properties decrease. Although halogenated flame retardants are effective, they produce toxic fumes when burned, which does not meet environmental protection requirements. Halogen-free flame retardant systems (phosphorus-based, nitrogen-based) often sacrifice mechanical properties, and high addition amounts affect processing fluidity.

[0007] Fourth, it has poor low-temperature impact resistance. The polybutadiene rubber phase in ABS undergoes a glass transition at low temperatures, causing the alloy's impact strength to drop sharply below -20°C, which limits its application in outdoor equipment (such as charging piles and communication cabinets) in cold regions.

[0008] Fifth, insufficient antistatic properties. Both PC and ABS are insulating materials with high surface resistivity, making them prone to static electricity buildup, which can lead to dust accumulation and even damage to precision electronic components. Traditional conductive fillers require large amounts and negatively impact mechanical properties; small-molecule antistatic agents are prone to migration and precipitation, resulting in short-lasting effects.

[0009] Therefore, developing a modified PC / ABS alloy that combines excellent compatibility, high heat resistance, efficient halogen-free flame retardancy, good low-temperature impact resistance, and long-lasting antistatic properties has significant industrial application value. Summary of the Invention

[0010] The purpose of this application is to provide a modified PC / ABS alloy and its preparation method to solve the above-mentioned problems.

[0011] To achieve the above objectives, the technical solution of this application is as follows:

[0012] A modified PC / ABS alloy, comprising the following components by weight:

[0013] Polycarbonate: 50-80 parts;

[0014] ABS resin: 15-40 parts;

[0015] Comb-like reactive compatibilizer: 3-8 parts;

[0016] Halogen-free flame retardant: 8-18 parts;

[0017] Nano talc: 3-10 parts;

[0018] Core-shell toughening agent: 2-8 parts;

[0019] Antistatic agent: 0.5–3 parts;

[0020] Antioxidant: 0.2–0.8 parts;

[0021] Lubricant: 0.2 to 1.0 parts.

[0022] Furthermore, the comb-shaped reactive compatibilizer is a comb-shaped copolymer with reactive groups grafted onto its main chain, wherein the reactive groups are selected from at least one of epoxy groups, acid anhydride groups, or oxazoline groups; the main chain of the comb-shaped reactive compatibilizer is a polystyrene-acrylonitrile copolymer, and the side chains are polymethyl methacrylate or polyglycidyl methacrylate; its number average molecular weight is 20,000 to 80,000, and the grafting rate is 5% to 20%.

[0023] Furthermore, the halogen-free flame retardant is a compound system of phosphorus-based flame retardant and nitrogen-based flame retardant, wherein the mass ratio of phosphorus-based flame retardant to nitrogen-based flame retardant is (1-3):1; the phosphorus-based flame retardant is selected from at least one of resorcinol bis, bisphenol A bis or triphenyl phosphate; the nitrogen-based flame retardant is selected from at least one of melamine cyanurate and melamine polyphosphate.

[0024] Furthermore, the halogen-free flame retardant also contains a silicone-based flame retardant synergist, the amount of which is 5% to 15% of the total mass of the halogen-free flame retardant; the silicone-based flame retardant synergist is selected from at least one of polysiloxane, organosilicon resin or silicone rubber powder.

[0025] Furthermore, the nano-talc powder is nano-talc powder with surface modification by a coupling agent, and its average particle size is 100-800 nm. The coupling agent is a silane coupling agent or a titanate coupling agent.

[0026] Furthermore, the core-shell toughening agent is a methyl methacrylate-butadiene-styrene copolymer or an acrylate core-shell toughening agent, with a core layer of butadiene rubber or butyl acrylate rubber and a shell layer of methyl methacrylate polymer, and a particle size of 100-300 nm.

[0027] Furthermore, the antistatic agent is a polyether ester amide antistatic agent or a quaternary ammonium salt polymeric permanent antistatic agent.

[0028] Furthermore, the antioxidant is a mixture of hindered phenolic antioxidants and phosphite antioxidants in a mass ratio of (1-2):1; the lubricant is selected from at least one of pentaerythritol stearate, ethylene bis-stearamide, or silicone powder.

[0029] A method for preparing the above-mentioned modified PC / ABS alloy includes:

[0030] (1) Raw material drying: Dry polycarbonate at 100-120℃ for 3-5 hours, and dry ABS resin at 80-90℃ for 2-4 hours;

[0031] (2) Premixing: Weigh the dried components according to the proportions, put them into a high-speed mixer, and mix them at 500-1500 rpm for 5-15 minutes at room temperature to 60°C to obtain the premix.

[0032] (3) Melt extrusion: The premixed material is added to a twin-screw extruder for melt blending and extrusion. The temperature settings of the twin-screw extruder are: Zone 1 200~220℃, Zone 2 220~240℃, Zone 3 230~250℃, Zone 4 230~250℃, Zone 5 220~240℃, Die head temperature 220~240℃, and screw speed 200~500rpm.

[0033] (4) Granulation: The extrudate is cooled and shaped in a cooling water tank, introduced into a pelletizer for granulation, and the pellets are collected to obtain the modified PC / ABS alloy.

[0034] Furthermore, in step (3), the length-to-diameter ratio of the twin-screw extruder is (36-48):1, and the vacuum degree is -0.04 to -0.08 MPa.

[0035] The modified PC / ABS alloy disclosed in this application exhibits improved tensile strength (56.3–66.8 MPa), flexural strength (88.4–98.5 MPa), flexural modulus (2480–2780 MPa), and notched impact strength (52.4–62.5 kJ / m² at 23°C). 2 -30℃: 28.5~36.2kJ / m 2 Heat distortion temperature (110~125℃), limiting oxygen index (30.0%~32.0%), flame retardant rating (V-0), and surface resistivity (5.2×10⁻⁶) are also specified. 9 ~2.5×10 10 The PC / ABS alloy exhibits excellent performance in all aspects (Ω), with overall performance significantly superior to the comparative examples. This indicates that the present invention successfully achieves high performance by employing a multi-dimensional synergistic design of comb-structured reactive compatibilizers, nano-talc powder, a phosphorus-nitrogen-silicon ternary synergistic flame retardant system, a core-shell toughening agent, and a polymeric antistatic agent. This allows it to meet the stringent requirements for comprehensive material performance in high-end applications such as automobiles, electronics, and communication equipment. Detailed Implementation

[0037] Example 1

[0038] This embodiment provides a modified PC / ABS alloy and its preparation method.

[0039] Weigh the following raw materials according to the following parts by weight:

[0040] PC (Bisphenol A type, melt index 10g / 10min, weight average molecular weight 30000): 65 parts;

[0041] ABS resin (rubber content 20wt%, melt index 18g / 10min): 25 parts;

[0042] Comb-shaped reactive compatibilizer (number average molecular weight 50,000, grafting rate 12%, epoxy group content 3.5wt%): 5 parts;

[0043] Halogen-free flame retardant: 12 parts, wherein the mass ratio of phosphorus-based flame retardant RDP to nitrogen-based flame retardant MPP is 2:1;

[0044] Silicon-based flame retardant synergist (polysiloxane): The addition amount is 10% of the total mass of the halogen-free flame retardant, i.e., 1.2 parts;

[0045] Nano-talc powder (average particle size 300nm, modified with silane coupling agent): 6 parts;

[0046] Core-shell toughening agent (MBS, particle size 200nm): 5 parts;

[0047] Antistatic agent (polyether ester amide block copolymer): 1.5 parts;

[0048] Antioxidant: 0.4 parts, wherein the mass ratio of antioxidant 1010 to antioxidant 168 is 1:1;

[0049] Lubricant (PETS): 0.5 parts;

[0050] The preparation method is as follows:

[0051] (1) Raw material drying: PC is dried at 110°C for 4 hours and ABS resin is dried at 85°C for 3 hours.

[0052] (2) Premixing: Weigh the dried components according to the above proportions, put them into a high-speed mixer, and mix them at 1000 rpm for 10 minutes at 50°C to obtain the premix.

[0053] (3) Melt extrusion: Add the premixed material to a twin-screw extruder with a length-to-diameter ratio of 40:1, set the screw speed to 350 rpm, the feeding frequency to 10 Hz, the vacuum degree to -0.06 MPa, and set the temperature of each section of the extruder as follows: Zone 1 210℃, Zone 2 230℃, Zone 3 240℃, Zone 4 240℃, Zone 5 230℃, and the die head temperature to 230℃.

[0054] (4) Granulation: The extrudate is cooled and shaped in a cooling water tank, introduced into a pelletizer for granulation, and the pellets are collected to obtain the modified PC / ABS alloy of this embodiment.

[0055] In step (3), the twin-screw extruder is divided into five zones along the material conveying direction: zone 1 (feeding section), zone 2 (conveyor section), zone 3 (melting section), zone 4 (homogenization section), zone 5 (metering section), and the die head zone. Among these:

[0056] Zone 1 (feeding section): The temperature is lower to prevent the material from melting and bridging too early at the feed inlet;

[0057] Zone 2 (Conveying Section): The temperature gradually rises, and the material begins to soften;

[0058] Zone 3 (Melting Section): This zone has the highest temperature, allowing the polymer to fully melt and plasticize.

[0059] Zone 4 (Homogenization Section): Maintain high temperature to ensure uniform mixing of all components;

[0060] Zone 5 (Metering Section): Temperature is moderately reduced to avoid overheating and degradation, and to ensure the stability of melt delivery;

[0061] The temperature in the die head area is similar to that in zone five, ensuring a smooth flow of melt.

[0062] Resorcinol bis refers to diphenyl phosphate, and bisphenol A bis refers to diphenyl phosphate.

[0063] Example 2

[0064] This embodiment provides a modified PC / ABS alloy and its preparation method.

[0065] Weigh the following raw materials according to the following parts by weight:

[0066] PC (Bisphenol A type, melt index 8g / 10min, weight average molecular weight 35000): 70 parts;

[0067] ABS resin (rubber content 18wt%, melt index 15g / 10min): 20 parts;

[0068] Comb-shaped reactive compatibilizer (number average molecular weight 40,000, grafting rate 10%, epoxy group content 3.0 wt%): 4 parts

[0069] Halogen-free flame retardant: 10 parts, wherein the mass ratio of phosphorus-based flame retardant BDP to nitrogen-based flame retardant MPP is 2:1;

[0070] Silicon-based flame retardant synergist (organic silicone resin): The addition amount is 10% of the total mass of the halogen-free flame retardant, i.e., 1.0 part;

[0071] Nano-talc powder (average particle size 400nm, modified with titanate coupling agent): 5 parts;

[0072] Core-shell toughening agent (acrylate core-shell toughening agent, particle size 250nm): 4 parts;

[0073] Antistatic agent (polyether ester amide block copolymer): 1.0 part;

[0074] Antioxidant: 0.4 parts, wherein the mass ratio of antioxidant 1076 to antioxidant 168 is 1:1;

[0075] Lubricant (EBS): 0.4 parts;

[0076] The preparation method is the same as in Example 1.

[0077] Example 3

[0078] This embodiment provides a modified PC / ABS alloy and its preparation method.

[0079] Weigh the following raw materials according to the following parts by weight:

[0080] PC (Bisphenol A type, melt index 12g / 10min, weight average molecular weight 25000): 55 parts;

[0081] ABS resin (rubber content 25wt%, melt index 20g / 10min): 30 parts;

[0082] Comb-shaped reactive compatibilizer (number average molecular weight 60,000, grafting rate 15%, epoxy group content 4.0 wt%): 6 parts;

[0083] Halogen-free flame retardant: 15 parts, wherein the mass ratio of phosphorus-based flame retardant TPP to nitrogen-based flame retardant MCA is 1.5:1;

[0084] Silicone-based flame retardant synergist (silicone rubber powder): The addition amount is 8% of the total mass of the halogen-free flame retardant, i.e., 1.2 parts;

[0085] Nano-talc powder (average particle size 200nm, modified with silane coupling agent): 8 parts;

[0086] Core-shell toughening agent (MBS, particle size 150nm): 6 parts;

[0087] Antistatic agent (polyether ester amide block copolymer): 2.0 parts;

[0088] Antioxidant: 0.5 parts, wherein the mass ratio of antioxidant 1010 to antioxidant 626 is 1.5:1;

[0089] Lubricant (silicone powder): 0.6 parts;

[0090] The preparation method is the same as in Example 1.

[0091] Example 4

[0092] This embodiment provides a modified PC / ABS alloy and its preparation method.

[0093] Weigh the following raw materials according to the following parts by weight:

[0094] PC (Bisphenol A type, melt index 6 g / 10 min, weight average molecular weight 38000): 75 parts;

[0095] ABS resin (rubber content 15wt%, melt index 12g / 10min): 15 parts;

[0096] Comb-shaped reactive compatibilizer (number average molecular weight 30,000, grafting rate 8%, epoxy group content 2.5wt%): 3 parts;

[0097] Halogen-free flame retardant: 8 parts, wherein the mass ratio of phosphorus-based flame retardant RDP to nitrogen-based flame retardant MCA is 3:1;

[0098] Silicon-based flame retardant synergist (polysiloxane): The addition amount is 5% of the total mass of the halogen-free flame retardant, i.e., 0.4 parts;

[0099] Nano-talc powder (average particle size 600nm, modified with titanate coupling agent): 3 parts;

[0100] Core-shell toughening agent (MBS, particle size 280nm): 3 parts;

[0101] Antistatic agent (polyether ester amide block copolymer): 0.8 parts;

[0102] Antioxidant: 0.3 parts, wherein the mass ratio of antioxidant 1010 to antioxidant 168 is 1.5:1;

[0103] Lubricant (PETS): 0.3 parts;

[0104] The preparation method is the same as in Example 1.

[0105] Example 5

[0106] This embodiment provides a modified PC / ABS alloy and its preparation method.

[0107] Weigh the following raw materials according to the following parts by weight:

[0108] PC (Bisphenol A type, melt index 14g / 10min, weight average molecular weight 22000): 50 parts;

[0109] ABS resin (rubber content 30wt%, melt index 22g / 10min): 35 parts;

[0110] Comb-shaped reactive compatibilizer (number average molecular weight 70,000, grafting rate 18%, epoxy group content 4.5wt%): 7 parts;

[0111] Halogen-free flame retardant: 16 parts, wherein the mass ratio of phosphorus-based flame retardant BDP to nitrogen-based flame retardant MPP is 1.2:1;

[0112] Silicon-based flame retardant synergist (organic silicone resin): The addition amount is 12% of the total mass of the halogen-free flame retardant, i.e., 1.92 parts;

[0113] Nano-talc powder (average particle size 150nm, modified with silane coupling agent): 9 parts;

[0114] Core-shell toughening agent (acrylate core-shell toughening agent, particle size 120nm): 7 parts;

[0115] Antistatic agent (polyether ester amide block copolymer): 2.5 parts;

[0116] Antioxidant: 0.7 parts, wherein the mass ratio of antioxidant 1076 to antioxidant 168 is 1.2:1;

[0117] Lubricant (EBS): 0.8 parts;

[0118] The preparation method is the same as in Example 1.

[0119] Comparative Example 1

[0120] This comparative example provides a modified PC / ABS alloy and its preparation method, differing from Example 1 only in that: no comb-like reactive compatibilizer is added, and instead, an equal weight portion of commercially available styrene-maleic anhydride copolymer (SMA, number average molecular weight approximately 50,000, maleic anhydride content 8 wt%) is used as the compatibilizer. The remaining components and preparation method are the same as in Example 1.

[0121] Comparative Example 2

[0122] This comparative example provides a modified PC / ABS alloy and its preparation method, differing from Example 1 only in that: nano-talc powder is not added, and the missing weight portion is made up by PC. The remaining components and preparation method are the same as in Example 1.

[0123] Comparative Example 3

[0124] This comparative example provides a modified PC / ABS alloy and its preparation method. The only difference from Example 1 is that no silicon-based flame retardant synergist is added to the halogen-free flame retardant. The other components and preparation methods are the same as in Example 1.

[0125] Comparative Example 4

[0126] This comparative example provides a modified PC / ABS alloy and its preparation method, differing from Example 1 only in that: no core-shell toughening agent is added, and the missing weight portion is made up by PC. The remaining components and preparation method are the same as in Example 1.

[0127] Comparative Example 5

[0128] This comparative example provides a modified PC / ABS alloy and its preparation method, differing from Example 1 only in that the antistatic agent is replaced with an equal weight portion of a commercially available nonionic small molecule antistatic agent (ethoxylated alkylamine). The remaining components and preparation method are the same as in Example 1.

[0129] Performance testing

[0130] The modified PC / ABS alloys obtained in Examples 1-5 and Comparative Examples 1-5 were subjected to performance tests, and the test methods are as follows:

[0131] (1) Tensile property test: The test was conducted in accordance with GB / T1040-2018 standard, using type I specimens, tensile rate of 50 mm / min, and ambient temperature of 23±2℃.

[0132] The test was conducted according to the national standard GB / T1040-2018, "Determination of Tensile Properties of Plastics". Type I (dumbbell-shaped) specimens were used, with a total length ≥150 mm, a narrow section width of 10 mm, and a thickness of 4 mm. The test was performed on a universal testing machine at an ambient temperature controlled at 23±2℃. The tensile rate was 50 mm / min. During the test, the specimen was clamped at both ends and stretched at a constant rate until fracture. The following parameters were recorded:

[0133] Tensile strength (MPa): The maximum tensile stress that a specimen can withstand during the tensile process, expressed by the formula σ=F max A calculates, where F max The maximum tensile force is N, and A is the initial cross-sectional area of ​​the specimen (mm²).

[0134] Elongation at break (%): The relative elongation of the gauge length when the specimen breaks.

[0135] (2) Bending performance test: conducted in accordance with GB / T9341-2018 standard, with sample size of 80mm×10mm×4mm, bending rate of 2mm / min, and span of 64mm.

[0136] The test was conducted according to the national standard GB / T9341-2018, "Determination of Flexural Properties of Plastics". The specimen dimensions were 80mm × 10mm × 4mm (length × width × thickness), with a span of 64mm (span-to-thickness ratio of 16:1). The test was performed on a universal testing machine at a bending rate of 2mm / min. A three-point bending loading method was used, with the indenter moving downwards at a constant speed until the specimen broke or reached maximum deformation. The following parameters were recorded:

[0137] Bending strength (MPa): The maximum bending stress that the specimen withstands during bending, expressed by the formula σ. f =3FL / (2bh 2 The calculation is performed, where F is the maximum bending force (N), L is the span (mm), b is the specimen width (mm), and h is the specimen thickness (mm).

[0138] Flexural modulus (MPa): The slope of the initial linear portion of the flexural stress-strain curve, reflecting the material's resistance to flexural deformation.

[0139] (3) Notched impact strength test: The test was conducted in accordance with GB / T1843-2018 standard, with a type A notch and a sample size of 80mm×10mm×4mm. The impact strength was tested at 23℃ and -30℃ respectively.

[0140] The impact strength of plastic cantilever beams was determined according to the national standard GB / T1843-2018. A type A notch was used, with a notch depth of 2 mm and a notch root radius of curvature of 0.25 mm. The specimen dimensions were 80 mm × 10 mm × 4 mm, with a standard notch machined in the middle. Impact strength was tested at 23℃ (room temperature) and -30℃ (low temperature). For the low-temperature test, the specimen needed to be placed in a -30℃ constant temperature chamber for at least 4 hours, and the impact was completed within 5 seconds of removal.

[0141] The impact test uses a cantilever beam impact testing machine. The pendulum energy is selected based on the material's toughness (typically 2.75 J or 5.5 J). The pendulum is released from a fixed height, breaking the notched specimen in one strike. Notched impact strength (kJ / m²) 2 The impact energy is calculated using the formula a=E / (h×b), where E is the impact energy (J), h is the remaining thickness of the sample (mm), and b is the width of the sample (mm).

[0142] This indicator is used to evaluate the toughness of materials under high-speed impact loads, especially low-temperature toughness, which is crucial for equipment used in cold regions.

[0143] (4) Heat distortion temperature test: conducted in accordance with GB / T1634-2019 standard, with sample size of 80mm×10mm×4mm, loading stress of 1.82MPa, and heating rate of 120℃ / h.

[0144] The heat deflection temperature was determined according to the national standard GB / T1634-2019, "Determination of Deflection Temperature of Plastics under Load". The sample size was 80mm × 10mm × 4mm, and a flat loading method was used (the sample width direction was perpendicular). The loading stress was 1.82MPa (i.e., high load method). The heating medium was methyl silicone oil, and the heating rate was 120℃ / h. The initial temperature was controlled to be approximately 50℃ lower than the expected deflection temperature. When the midpoint of the sample reached the specified deflection change (usually 0.34mm, corresponding to the standard deflection value), the temperature of the oil bath at this point was recorded as the heat deflection temperature.

[0145] Heat distortion temperature characterizes the heat resistance of a material under the combined action of heat and load, and is a key indicator for evaluating the dimensional stability of a material in a high-temperature environment.

[0146] (5) Flame retardant performance test: conducted according to UL94 standard, with sample size of 125mm×13mm×1.6mm, vertical burning test, and limiting oxygen index (LOI) tested according to GB / T2406-2009 standard.

[0147] Vertical burning tests were conducted according to the US UL94 standard, "Tests for the flammability of plastic materials used in equipment and appliance components." The sample dimensions were 125mm × 13mm × 1.6mm (1.6mm thickness). Before testing, the samples were placed in an environment of 23±2℃ and 50±5% relative humidity for 48 hours. During testing, the samples were fixed vertically with absorbent cotton placed underneath. A Bunsen burner was applied for 10 seconds, and the afterflame time (t1) was recorded. After removing the burner, the burner was applied again for 10 seconds, and the second afterflame time (t2) and afterglow time (t3) were recorded. Simultaneously, it was recorded whether dripping material ignited the absorbent cotton. The flame retardancy rating (V-0, V-1, V-2, or NR) was determined based on the afterflame time, afterglow time, and dripping. V-0 rating requirements: t1 or t2 ≤ 10 seconds for each sample, t1 + t2 ≤ 50 seconds for all samples, t3 ≤ 30 seconds, and no dripping material igniting the cotton.

[0148] Simultaneously, the limiting oxygen index (LOI) was tested according to the national standard GB / T2406-2009 "Determination of Combustion Behavior of Plastics by Oxygen Index Method". The sample size was 80mm×10mm×4mm. During the test, the sample was vertically fixed in the combustion chamber, and the mixed flow of oxygen and nitrogen was adjusted to maintain the minimum oxygen concentration (volume fraction) required for combustion. The higher the LOI value, the more difficult the material is to burn and the better its flame retardancy.

[0149] (6) Surface resistivity test: The test shall be conducted in accordance with GB / T1410-2017 standard, with a test voltage of 500V, a test ambient temperature of 23±2℃, and a relative humidity of 50±5%. The sample shall be placed in a standard environment for 24 hours before the test.

[0150] The test was conducted according to the national standard GB / T1410-2017, "Test Methods for Volume Resistivity and Surface Resistivity of Solid Insulating Materials". The test voltage was 500V, and a three-electrode system (protective electrode, measuring electrode, and high-voltage electrode) was used. The sample was a circular disc with a diameter of 100mm and a thickness of 2mm, and its surface was clean and dry. The ambient temperature was 23±2℃, and the relative humidity was 50±5%. Before the test, the sample was placed in this environment for 24 hours to allow for moisture absorption equilibration.

[0151] Surface resistivity (Ω) is defined as the ratio of the DC electric field intensity to the linear current density on the surface of an insulating material, reflecting the material's ability to resist electrostatic accumulation. Surface resistivity <10 Ω 12 Materials with an Ω ohm rating are generally considered to have antistatic properties; <10 10 At Ω, it exhibits excellent antistatic effect. Polyether ester amide antistatic agents reduce the surface resistivity to 10 by forming a hydrophilic conductive layer on the surface. 9 ~10 11 Ω range.

[0152] The test results are shown in Tables 1 and 2 below:

[0153] Test Project Example 1 Example 2 Example 3 Example 4 Example 5 Tensile strength (MPa) 62.5 64.2 58.9 66.8 56.3 Bending strength (MPa) 95.6 97.8 90.2 98.5 88.4 Flexural modulus (MPa) 2650 2720 2520 2780 2480 <![CDATA[Izod impact strength (23 °C, kJ / m 2 )]]> 58.5 56.8 60.2 52.4 62.5 <![CDATA[Izod impact strength (-30 °C, kJ / m 2 ).]]> 32.6 31.2 34.8 28.5 36.2 Heat distortion temperature (1.82 MPa, °C) 118 121 114 125 110 Limiting oxygen index (%) 31.5 32.0 30.5 30.0 31.8 UL94 flame retardant rating (1.6mm) V-0 V-0 V-0 V-0 V-0 Surface resistivity (Ω) <![CDATA[8.5×10 9 ]]> <![CDATA[9.2×10 9 ]]> <![CDATA[6.8×10 9 ]]> <![CDATA[2.5×10 10 ]]> <![CDATA[5.2×10 9 ]]>

[0154] Table 1

[0155] Test Project Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Tensile strength (MPa) 52.3 60.1 61.8 63.0 60.5 Bending strength (MPa) 82.5 88.3 94.2 96.0 92.8 Flexural modulus (MPa) 2380 2350 2600 2620 2580 <![CDATA[Izod impact strength (23 °C, kJ / m 2 ).]]> 42.6 55.2 57.5 38.2 56.0 <![CDATA[Notched impact strength (-30 °C, kJ / m 2 )]]> 21.5 30.5 32.0 18.5 30.8 Heat distortion temperature (1.82 MPa, °C) 112 102 116 119 116 Limiting oxygen index (%) 31.0 31.2 28.5 31.5 31.2 UL94 flame retardant rating (1.6mm) V-0 V-0 V-2 V-0 V-0 Surface resistivity (Ω) <![CDATA[1.2×10 13 ]]> <![CDATA[8.8×10 9 ]]> <![CDATA[8.2×10 9 ]]> <![CDATA[8.5×10 9 ]]> <![CDATA[8.5×10 11 ]]>

[0156] Table 2

[0157] Results Analysis and Discussion

[0158] (1) Verification of the effect of comb-structured reactive compatibilizer

[0159] Comparing the test results of Example 1 and Comparative Example 1, it can be seen that Example 1, which uses the comb-shaped reactive compatibilizer of the present invention, exhibits better tensile strength (62.5 MPa vs. 52.3 MPa), flexural strength (95.6 MPa vs. 82.5 MPa), and notched impact strength at 23°C (58.5 kJ / m² vs. 42.6 kJ / m²). 2 ) and -30℃ notched impact strength (32.6kJ / m 2 Comparison of 21.5 kJ / m 2 In terms of both aspects, it is significantly superior to Comparative Example 1, which uses a traditional SMA compatibilizer. This indicates that the comb-structured reactive compatibilizer, through its unique "double comb" type interface structure, forms a more stable and efficient interfacial bonding layer at the PC / ABS two-phase interface, effectively enhancing the interfacial bonding force and thus significantly improving the mechanical properties of the alloy.

[0160] (2) Heat resistance modification effect of nano-talc

[0161] Comparing the test results of Example 1 and Comparative Example 2, it can be seen that the heat distortion temperature of Example 1 with added nano-talc is 118℃, while the heat distortion temperature of Comparative Example 2 without added nano-talc is only 102℃, a decrease of 16℃. Simultaneously, the flexural modulus of Example 1 (2650MPa) is also significantly higher than that of Comparative Example 2 (2350MPa). This indicates that nano-talc, as rigid particles, is uniformly dispersed in the PC / ABS matrix, effectively improving the heat resistance and rigidity of the material. It is worth noting that the addition of nano-talc did not significantly sacrifice the impact toughness of the alloy, which is attributed to its nanoscale composition and the surface modification treatment with the coupling agent.

[0162] (3) Flame retardant synergistic effect of silicon-based flame retardant synergists

[0163] Comparing the test results of Example 1 and Comparative Example 3, it can be seen that: Example 1, with the addition of a silicon-based flame retardant synergist, has a limiting oxygen index of 31.5% and a UL94 flame retardancy rating of V-0; while Comparative Example 3, without the addition of a silicon-based flame retardant synergist, has a limiting oxygen index of 28.5% and a UL94 flame retardancy rating of only V-2. This indicates that the introduction of the silicon-based flame retardant synergist forms a phosphorus-nitrogen-silicon ternary synergistic flame retardant system. The silicon-based flame retardant synergist forms a ceramic protective layer during combustion, synergistically promoting the formation of a dense char layer with the phosphorus and nitrogen-based flame retardants, significantly improving flame retardant efficiency.

[0164] (4) Toughening effect of core-shell toughening agent

[0165] Comparing the test results of Example 1 and Comparative Example 4, it can be seen that the notched impact strength of Example 1 with MBS core-shell toughening agent added is 58.5 kJ / m at 23℃ and -30℃. 2 and 32.6 kJ / m 2 The impact strength of Comparative Example 4, without the addition of toughening agent, was 38.2 kJ / m. 2 and 18.5 kJ / m 2 The reduction was significant. Particularly noteworthy is that, at -30°C, the impact strength retention rate of Example 1 (relative to 23°C) was 55.7%, while that of Comparative Example 4 was only 48.4%. This indicates that the MBS core-shell toughening agent maintains excellent toughening performance even at low temperatures, and its core butadiene rubber retains good flexibility at low temperatures, effectively absorbing impact energy through cavitation and shear yielding mechanisms.

[0166] (5) Antistatic effect of polymeric antistatic agents

[0167] Comparing the test results of Example 1 and Comparative Example 5, it can be seen that the surface resistivity of Example 1, which uses a polyether ester amide polymeric antistatic agent, is 8.5 × 10⁻⁶. 9 Ω, meeting the standards for antistatic materials (typically requiring a surface resistivity of <10). 12 The surface resistivity of Comparative Example 5, which uses a small-molecule antistatic agent, is 8.5 × 10⁻⁶ Ω); while the surface resistivity of Comparative Example 5 is 8.5 × 10⁻⁶ Ω. 11 Although Ω also meets the antistatic standard, according to the mechanism of action of antistatic agents, small molecule antistatic agents are more likely to migrate and precipitate during long-term use, leading to a decrease in antistatic effect. Meanwhile, the tensile strength and impact strength of Comparative Example 5 are both lower than those of Example 1, indicating that small molecule antistatic agents have a greater negative impact on the mechanical properties of the matrix.

[0168] The test results of Examples 1-5 above show that the modified PC / ABS alloy prepared by the present invention exhibits good tensile strength (56.3-66.8 MPa), flexural strength (88.4-98.5 MPa), flexural modulus (2480-2780 MPa), and notched impact strength (23℃: 52.4-62.5 kJ / m). 2 -30℃: 28.5~36.2kJ / m 2 Heat distortion temperature (110~125℃), limiting oxygen index (30.0%~32.0%), flame retardant rating (V-0), and surface resistivity (5.2×10⁻⁶) are also specified. 9 ~2.5×10 10 The PC / ABS alloy exhibits excellent performance in all aspects (Ω), with overall performance significantly superior to the comparative examples. This indicates that the present invention successfully achieves high performance by employing a multi-dimensional synergistic design of comb-structured reactive compatibilizers, nano-talc powder, a phosphorus-nitrogen-silicon ternary synergistic flame retardant system, a core-shell toughening agent, and a polymeric antistatic agent. This allows it to meet the stringent requirements for comprehensive material performance in high-end applications such as automobiles, electronics, and communication equipment.

[0169] Industrial applicability

[0170] The modified PC / ABS alloy provided by this invention possesses excellent mechanical properties, heat resistance, halogen-free flame retardant properties, low-temperature impact resistance, and antistatic properties. Its comprehensive performance is outstanding, and it can be widely used in the following fields:

[0171] (1) Automotive industry: automotive dashboards, center consoles, door panel interior parts, seat guards, air conditioning vents, engine compartment parts, etc., especially suitable for new energy vehicle charging pile housings with high requirements for heat resistance and low temperature impact resistance.

[0172] (2) Electronic appliances: laptop casings, monitor bezels, printer casings, copier parts, and household appliance casings, etc.

[0173] (3) Communication equipment: 5G communication base station shells, antenna covers, router shells, server chassis, etc., in application scenarios with high requirements for flame retardancy and antistatic properties.

[0174] (4) Financial equipment: ATM casing, POS machine casing, banknote detector parts, etc.

[0175] (5) Medical devices: medical equipment housings, diagnostic instrument housings, etc.

[0176] The preparation method of the present invention is simple, easy to operate, and easy to industrialize, and has good economic benefits and market application prospects.

[0177] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this application.

Claims

1. A modified PC / ABS alloy, characterized in that, By weight, it includes the following components: Polycarbonate: 50-80 parts; ABS resin: 15-40 parts; Comb-like reactive compatibilizer: 3-8 parts; Halogen-free flame retardant: 8-18 parts; Nano talc: 3-10 parts; Core-shell toughening agent: 2-8 parts; Antistatic agent: 0.5–3 parts; Antioxidant: 0.2–0.8 parts; Lubricant: 0.2 to 1.0 parts.

2. The modified PC / ABS alloy according to claim 1, characterized in that, The comb-shaped reactive compatibilizer is a comb-shaped copolymer with reactive groups grafted onto its main chain. The reactive groups are selected from at least one of epoxy groups, acid anhydride groups, or oxazoline groups. The main chain of the comb-shaped reactive compatibilizer is a polystyrene-acrylonitrile copolymer, and the side chains are polymethyl methacrylate or polyglycidyl methacrylate. Its number average molecular weight is 20,000 to 80,000, and the grafting rate is 5% to 20%.

3. The modified PC / ABS alloy according to claim 1, characterized in that, The halogen-free flame retardant is a compound system of phosphorus-based flame retardant and nitrogen-based flame retardant, wherein the mass ratio of phosphorus-based flame retardant to nitrogen-based flame retardant is (1-3):1; the phosphorus-based flame retardant is selected from at least one of resorcinol bis, bisphenol A bis or triphenyl phosphate; the nitrogen-based flame retardant is selected from at least one of melamine cyanurate and melamine polyphosphate.

4. The modified PC / ABS alloy according to claim 1, characterized in that, The halogen-free flame retardant also contains a silicon-based flame retardant synergist, the amount of which is 5% to 15% of the total mass of the halogen-free flame retardant; the silicon-based flame retardant synergist is selected from at least one of polysiloxane, organosilicon resin or silicone rubber powder.

5. The modified PC / ABS alloy according to claim 1, characterized in that, The nano-talc powder is a nano-talc powder with a surface modified by a coupling agent, and its average particle size is 100-800 nm. The coupling agent is a silane coupling agent or a titanate coupling agent.

6. The modified PC / ABS alloy according to claim 1, characterized in that, The core-shell toughening agent is a methyl methacrylate-butadiene-styrene copolymer or an acrylate core-shell toughening agent, with a core layer of butadiene rubber or butyl acrylate rubber and a shell layer of methyl methacrylate polymer, and a particle size of 100-300 nm.

7. The modified PC / ABS alloy according to claim 1, characterized in that, The antistatic agent is a polyether ester amide antistatic agent or a quaternary ammonium salt polymeric permanent antistatic agent.

8. The modified PC / ABS alloy according to claim 1, characterized in that, The antioxidant is a mixture of hindered phenolic antioxidants and phosphite antioxidants in a mass ratio of (1-2):1; the lubricant is selected from at least one of pentaerythritol stearate, ethylene bis-stearamide, or silicone powder.

9. A method for preparing the modified PC / ABS alloy according to any one of claims 1-8, comprising: (1) Raw material drying: Dry polycarbonate at 100-120℃ for 3-5 hours, and dry ABS resin at 80-90℃ for 2-4 hours; (2) Premixing: Weigh the dried components according to the proportions, put them into a high-speed mixer, and mix them at 500-1500 rpm for 5-15 minutes at room temperature to 60°C to obtain the premix. (3) Melt extrusion: The premixed material is added to a twin-screw extruder for melt blending and extrusion. The temperature settings of the twin-screw extruder are: Zone 1 200~220℃, Zone 2 220~240℃, Zone 3 230~250℃, Zone 4 230~250℃, Zone 5 220~240℃, Die head temperature 220~240℃, and screw speed 200~500rpm. (4) Granulation: The extrudate is cooled and shaped in a cooling water tank, introduced into a pelletizer for granulation, and the pellets are collected to obtain the modified PC / ABS alloy.

10. The preparation method according to claim 9, characterized in that, In step (3), the length-to-diameter ratio of the twin-screw extruder is (36-48):1, and the vacuum degree is -0.04 to -0.08 MPa.