Polycarbonate composition and preparation method therefor

Abstract

Disclosed are a polycarbonate composition and a preparation method thereof. The product introduces a specific proportioning amount of an acrylate copolymer to serve as a component for improving processing fluidity, such that the product has excellent processing fluidity in thin-wall designing, and also has ideal mechanical properties and flame retardance.

Description

Polycarbonate composition and preparation method thereof Technical Field

[0001] The present application relates to the technical field of polymer materials, and in particular to a polycarbonate composition and a preparation method thereof. Background Art

[0002] Polycarbonate is a highly rigid molecular structure material, so materials or alloys synthesized based on polycarbonate generally have problems such as poor fluidity and difficulty in processing.

[0003] In the prior art, small molecule lubricants are often introduced as additives to improve the processing fluidity of polycarbonate compositions. However, this practice generally leads to a significant reduction in the toughness of the product, especially for some thin-walled products. Not only are the products unusable due to toughness issues, but they may even crack during processing. At the same time, the introduction of these small molecule lubricants may cause compatibility issues with other functional components in the polycarbonate composition (such as flame retardants, toughening agents, etc.), resulting in precipitation and ultimately causing appearance problems in the product. Summary of the Invention

[0004] The present application provides a polycarbonate composition, which introduces a specific ratio of acrylic copolymer as a processing fluidity improving component, thereby not only enabling the product to have excellent processing fluidity during thin-wall design, but also having ideal mechanical properties and flame retardant properties.

[0005] The present application provides a polycarbonate composition, comprising the following components in parts by weight: 60 to 90 parts of polycarbonate, 10 to 50 parts of ABS (acrylonitrile-butadiene-styrene terpolymer) resin, and 0.5 to 5 parts of a processing fluidity improver; the processing fluidity improver is an acrylic ester copolymer with a weight-average molecular weight ≥500,000.

[0006] In some embodiments, the acrylate copolymer has a weight average molecular weight of 500,000 to 4,500,000.

[0007] In some embodiments, the non-Newtonian index of the polycarbonate is 0.15 to 0.83. In some embodiments, the non-Newtonian index of the polycarbonate is 0.2 to 0.56.

[0008] In some embodiments, the polycarbonate has a melt flow rate of 0.6 to 70 g / 10 min at 300° C. and 1.2 kg load according to ISO 1133-2011. In some embodiments, the polycarbonate has a melt index of 2 to 26 g / 10 min at 300° C. and 1.2 kg load according to ISO 1133-2011.

[0009] In some embodiments, the polycarbonate composition further comprises the following components in parts by weight: 0.1 to 10 parts of a toughening agent, 0.01 to 5 parts of a flame retardant, and 0.1 to 5 parts of an anti-dripping agent.

[0010] In some embodiments, the toughening agent is at least one of SAN grafted PB rubber (styrene-acrylonitrile copolymer grafted polybutadiene rubber), MMA (methyl methacrylate) grafted silicone rubber, SAN (styrene-acrylonitrile copolymer) grafted silicone rubber, SEBS (styrene-ethylene-butylene-styrene block copolymer), and MBS (terpolymer of methyl methacrylate-butadiene-styrene).

[0011] In some embodiments, the weight portion of the processing fluidity improver is 1 to 4 parts.

[0012] In some embodiments, the acrylate copolymer is polymethyl methacrylate.

[0013] The present application also provides a method for preparing the polycarbonate composition, comprising the following steps: uniformly mixing the components, and then melt-extruding and granulating the components in a twin-screw extruder to obtain the polycarbonate composition.

[0014] The present application also provides use of the polycarbonate composition in preparing thin-walled portable electronic products.

[0015] The beneficial effect of the present application is that the present application provides a high-flow polycarbonate composition, which introduces a specific ratio of acrylic copolymer as a processing fluidity-improving component, thereby not only enabling the product to have excellent processing fluidity during thin-wall design, but also having ideal mechanical properties and flame retardant properties. DETAILED DESCRIPTION

[0016] The present application provides a polycarbonate composition comprising the following components in parts by weight:

[0017] 60-90 parts of polycarbonate, 10-50 parts of ABS resin, 0.5-5 parts of processing fluidity improver;

[0018] The processing fluidity improver is an acrylic acid ester copolymer with a weight average molecular weight of ≥500,000.

[0019] In some embodiments, the acrylate copolymer has a weight average molecular weight of 500,000 to 4,500,000.

[0020] In some embodiments, the acrylate copolymer is polymethyl methacrylate.

[0021] In some embodiments, the components of the polycarbonate composition further include 0.1 to 10 parts of a toughening agent, 0.01 to 5 parts of a flame retardant, and 0.1 to 5 parts of an anti-dripping agent.

[0022] In some embodiments, the weight portion of the processing fluidity improver is 1 to 4 parts.

[0023] In some embodiments, the polycarbonate composition comprises the following components in parts by weight: 65-85 parts of polycarbonate, 15-40 parts of ABS resin, 0.2-3 parts of toughening agent, 0.1-1 part of flame retardant, 1-4 parts of processing fluidity improver and 0.2-0.8 parts of anti-dripping agent.

[0024] While the introduction of small molecule lubricants into traditional polycarbonate compositions can improve the processing fluidity of the product, the toughness of the product decreases, and the decrease is particularly pronounced when preparing thin-walled products. Furthermore, the degree to which these lubricants improve processing fluidity is very limited, with the helix length of the prepared product unable to exceed 280°. Compatibility issues with other components can also cause product component separation, resulting in surface defects such as silver streaks. Based on these technical difficulties, the product described in this application uses a macromolecular acrylate copolymer with a weight-average molecular weight ≥500,000 (the weight-average molecular weight of a general acrylate copolymer additive is about 200,000) as a processing fluidity improver to improve the processing fluidity of the PC / ABS composition. It is well known to those skilled in the art that as the weight-average molecular weight increases, the acrylate copolymer will increase the viscosity of the composition. However, the inventors have discovered that under the action of the macromolecular acrylate copolymer, the molecular entanglement of polycarbonate and ABS resin will be greatly increased, and the phase distribution of the two will be refined. Not only will the processing fluidity be significantly improved, but the toughness of the product can also be maintained at a considerable level. On the other hand, since the acrylate copolymer is not a small molecule substance and the addition amount is small, it will not cause precipitation of the product, and the product appearance is good.

[0025] However, excessive amounts of this processing fluidity improver should be avoided, as this will rapidly deteriorate the product's processing fluidity and deteriorate its overall performance. The inventors have discovered that maintaining the weight-average molecular weight of the processing fluidity improver within the range of 500,000 to 4,500,000, and maintaining the added weight within the preferred range, allows the product to achieve both optimal processing fluidity and toughness under thin-wall conditions.

[0026] In some embodiments, the acrylate copolymer has a weight average molecular weight of 500,000 to 2,800,000.

[0027] In some embodiments, the weight average molecular weight of the acrylic ester copolymer is directly measured by a small-angle laser scattering method.

[0028] In some embodiments, the acrylate copolymer has a weight average molecular weight of 500,000, 600,000, 700,000, 800,000, 900,000, 1,000,000, 1,200,000, 1,500,000, 1,800,000, 2,000,000, 2,200,000, 2,500,000, 2,800,000, 3,000,000, 3,500,000, 4,000,000, or 4,500,000.

[0029] In some embodiments, the acrylate copolymer has a weight average molecular weight of 500,000 to 1,500,000.

[0030] In some embodiments, the weight percentage of the polycarbonate is in the range of 65 parts, 70 parts, 75 parts, 80 parts, 85 parts, or any two of them. In some embodiments, the weight percentage of the ABS resin is in the range of 15 parts, 20 parts, 25 parts, 30 parts, 35 parts, 40 parts, or any two of them. In some embodiments, the weight percentage of the toughening agent is in the range of 0.2 parts, 0.5 parts, 0.8 parts, 1 part, 1.2 parts, 1.5 parts, 1.8 parts, 2 parts, 2.5 parts, 3 parts, or any two of them. In some embodiments, the weight percentage of the flame retardant is in the range of 0.1 parts, 0.2 parts, 0.5 parts, 0.8 parts, 1 part, or any two of them. In some embodiments, the weight percentage of the processing flow improver is in the range of 1 part, 1.5 parts, 2 parts, 2.5 parts, 3 parts, 3.5 parts, or 4 parts, or any two of them. In some embodiments, the weight percentage of the anti-dripping agent is in the range of one or any two of 0.2 parts, 0.4 parts, 0.5 parts, 0.6 parts, and 0.8 parts.

[0031] The inventors have confirmed many times that the acrylic acid ester copolymer described in the present application can be a product prepared by conventional methods in the art, or a product directly purchased from the market.

[0032] In some embodiments, the polycarbonate composition comprises the following components in parts by weight: 70-80 parts of polycarbonate, 20-30 parts of ABS resin, 0.5-1 part of toughening agent, 0.2-0.5 part of flame retardant, 2-3 parts of processing fluidity improver and 0.3-0.5 part of anti-dripping agent.

[0033] In some embodiments, in the polycarbonate composition, the mass percentage of polycarbonate is ≥50 wt %.

[0034] In some embodiments, the polycarbonate is bisphenol A polycarbonate.

[0035] In some embodiments, the non-Newtonian index of the polycarbonate is 0.15 to 0.83;

[0036] In some embodiments, the non-Newtonian index of the polycarbonate is 0.18 to 0.64;

[0037] In some embodiments, the non-Newtonian index of the polycarbonate is 0.2 to 0.56;

[0038] In some embodiments, the non-Newtonian index of the polycarbonate is in the range of one or any two of 0.2, 0.21, 0.28, 0.3, 0.33, 0.37, 0.4, 0.45, 0.5, 0.55, and 0.56.

[0039] In some embodiments, the polycarbonate has a non-Newtonian index of ≤ 0.5.

[0040] In some embodiments, the polycarbonate has a non-Newtonian index of 0.21 to 0.45.

[0041] In some embodiments, the non-Newtonian index of the polycarbonate is tested by capillary rheometer testing: a die with an aspect ratio of 30:1, an inlet angle of 180°, and a shear rate γ of 100, 500, 1000, 2000, 3000, or 5000 s is selected. -1 ; The shear temperature T is fixed at 260°C; the constant temperature time is 6 minutes, and the melt is extruded from the capillary at a constant shear rate. The instrument automatically records the shear stress τ. For polymer melts, the shear rate and shear stress obey the power law formula (τ = Kγn; viscosity = Kγn-1). By plotting lgτ and lgγ, a straight line is obtained, and its slope is the non-Newtonian index.

[0042] When selecting the type of polycarbonate, the inventors found that when the non-Newtonian index of the polycarbonate is maintained in the range of ≤0.5, the processing rheological properties of the product can be further improved.

[0043] In some embodiments, the polycarbonate has a melt flow rate of 0.6 to 70 g / 10 min at 300° C. and a load of 1.2 kg according to ISO 1133-2011;

[0044] In some embodiments, the polycarbonate has a melt flow rate of 1 to 45 g / 10 min at 300° C. and a load of 1.2 kg according to ISO 1133-2011;

[0045] In some embodiments, the polycarbonate has a melt flow rate of 2 to 26 g / 10 min at 300° C. and a load of 1.2 kg according to ISO 1133-2011.

[0046] In some embodiments, the polycarbonate has a melt flow rate of 2.17 to 19.8 g / 10 min at 300° C. and a load of 1.2 kg according to ISO 1133-2011.

[0047] In some embodiments, the polycarbonate has a melt flow rate at 300° C. and 1.2 kg load according to ISO 1133-2011 of 2.1 g / 10 min, 2.17 g / 10 min, 2.5 g / 10 min, 2.8 g / 10 min, 2.83 g / 10 min, 3 g / 10 min, 3.43 g / 10 min, 4 g / 10 min, 5 g / 10 min, 8 g / 10 min, 9 g / 10 min, 9.82 g / 10 min, 10 g / 10 min, 12 g / 10 min, 12.4 g / 10 min, 13 g / 10 min, 15 g / 10 min, 18 g / 10 min, 19 g / 10 min, or 19.8 g / 10 min, or any two thereof.

[0048] After multiple verifications by the inventors, the polycarbonate described in this application can be a homemade product using conventional methods, or a product purchased directly from the market. The homemade product can be a product of the same system, or a product prepared by different system methods.

[0049] In some embodiments, the ABS resin has a melt index of 7 to 30 g / 10 min at 220° C. and a load of 10 kg according to ISO 1133-2011.

[0050] In some embodiments, the ABS resin has a melt index of 7.8 to 28.7 g / 10 min at 220° C. and a load of 10 kg according to ISO 1133-2011.

[0051] In some embodiments, the relative contents of acrylonitrile, butadiene, and styrene in the ABS resin can be conventionally selected by those skilled in the art and are not limited or elaborated herein.

[0052] In some embodiments, in the polycarbonate composition, the total mass content of polycarbonate and ABS resin is not less than 60 wt %.

[0053] In some embodiments, the toughening agent is at least one of SAN grafted PB rubber, MMA grafted silicone rubber, SAN grafted silicone rubber, SEBS, and MBS.

[0054] In some embodiments, the toughening agent has a melt index of 0.1 to 5 g / 10 min at 300° C. and a load of 1.2 kg according to ISO 1133-2011.

[0055] In some embodiments, the flame retardant is a halogen-free flame retardant.

[0056] In some embodiments, the halogen-free flame retardant is at least one of a phosphorus-based flame retardant, a sulfonate flame retardant, an organosilicon flame retardant, and an inorganic filler flame retardant.

[0057] In some embodiments, the halogen-free flame retardant is a phosphorus-based flame retardant, and the phosphorus content in the phosphorus-based flame retardant can be conventionally selected, for example, ≥9.0 wt %, or for example ≥10 wt %.

[0058] In some embodiments, the phosphorus-based flame retardant is at least one of DOPO (also known as DOP, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide), TPP (triphenyl phosphate), BDP (bisphenol A bis(diphenyl phosphate)), RDP (resorcinol(diphenyl phosphate)), phosphazene, and phosphate. In some embodiments, the phosphorus-based flame retardant is 1,3-ylidenephosphotetrakis(2,6-dimethyl)phosphate.

[0059] In some embodiments, the anti-drip agent is at least one of polytetrafluoroethylene and styrene-acrylonitrile copolymer.

[0060] In some embodiments, the components of the polycarbonate further include at least one of 0.01 to 1 parts by weight of an antioxidant, 0.01 to 1 parts by weight of a lubricant, 0.01 to 1 parts by weight of a light stabilizer, and 0.01 to 1 parts by weight of a colorant.

[0061] Based on the actual needs of the product, those skilled in the art can appropriately introduce some components commonly introduced into polycarbonate products without affecting the performance of the product, such as antioxidants to improve the aging resistance of the product, lubricants to improve the processing performance of the product, light stabilizers to improve the light aging resistance of the product when thin-walled, and colorants to give the product various colors, etc.

[0062] The present application also provides a method for preparing the polycarbonate composition, comprising the following steps:

[0063] After the components are uniformly mixed, they are melt-extruded and granulated in a twin-screw extruder to obtain the polycarbonate composition.

[0064] The preparation method of the polycarbonate composition described in the present application has simple operating steps and can realize industrial-scale production.

[0065] In some embodiments, the temperature range of the twin-screw extruder is set to: 220-280° C., the screw speed is 200-600 r / min, and the screw aspect ratio is 35-60:1 (eg, 48:1).

[0066] In some embodiments, all components are fed into a twin-screw extruder from a main feeding port for melt blending, extrusion and granulation.

[0067] In some embodiments, when the components are melt-blended and extruded, the temperature zones of the twin-screw extruder are set as follows: zone 1 200-220°C, zone 2 210-230°C, zone 3 215-235°C, zone 4 215-235°C, zone 5 215-235°C, zone 6 220-245°C, zone 7 220-245°C, zone 8 220-245°C, zone 9 220-240°C, zone 10 220-240°C, zone 11 210-230, zone 12 200-220°C.

[0068] The present application also provides use of the polycarbonate composition in preparing thin-walled portable electronic products.

[0069] In some embodiments, the thin-walled portable electronic product includes a tablet computer and a mobile phone.

[0070] In some embodiments, the polycarbonate composition is used to prepare a housing of the thin-walled portable electronic product or a protective device for internal integrated circuit electronic components.

[0071] The polycarbonate composition described in the present application has extremely high processing fluidity and a long spiral length (in some embodiments, it can reach more than 280). At the same time, it can achieve ideal flame retardancy and toughness at a thin-walled level, has a good appearance, and excellent comprehensive performance. It is particularly suitable for the preparation of some thin-walled and lightweight portable electronic products, and has been verified to be able to achieve normal use at a thickness of 1.5 mm or less.

[0072] In order to better illustrate the purpose, technical solutions and advantages of the present application, the present application will be further described below in conjunction with specific embodiments and comparative examples. Its purpose is to understand the content of the present application in detail, rather than to limit the present application. All other embodiments obtained by those of ordinary skill in the art without making creative work are within the scope of protection of the present application. The experimental reagents and instruments involved in the implementation of this application are all commonly used ordinary reagents and instruments unless otherwise specified.

[0073] Examples 1 to 17

[0074] The present application discloses a polycarbonate composition and an embodiment of its application. The components of the polycarbonate composition are shown in Table 1.

[0075] The preparation method of the polycarbonate composition comprises the following steps:

[0076] All the components in the formula are mixed uniformly in a high-speed mixer, and then fed into a twin-screw extruder from a main feeding port for melt blending, extrusion and granulation to obtain the polycarbonate composition.

[0077] When the components are melt-blended and extruded, the temperature zones of the twin-screw extruder are set to 200-220°C in zone 1, 210-230°C in zone 2, 215-235°C in zone 3, 215-235°C in zone 4, 215-235°C in zone 5, 220-245°C in zone 6, 220-245°C in zone 7, 220-245°C in zone 8, 220-240°C in zone 9, 220-240°C in zone 10, 210-230 in zone 11, and 200-220°C in zone 12. The screw speed is 400 rpm and the screw aspect ratio is 48:1.

[0078] Comparative Examples 1 to 9

[0079] The difference between the comparative examples and the examples is only in the types and proportions of the components, as shown in Table 2.

[0080] Among the components described in each embodiment and comparative example,

[0081] The polycarbonate 1 is 2100, produced by Wanhua Chemical, with a melt flow rate (ISO1133-2011) of 9.82 g / 10 min at 300°C and a load of 1.2 kg, and a non-Newtonian index of 0.45;

[0082] The polycarbonate 2 is 7030PJ, produced by Mitsubishi, Japan, with a melt flow rate (ISO1133-2011) of 3.43 g / 10 min at 300° C. and a load of 1.2 kg, and a non-Newtonian index of 0.33;

[0083] The polycarbonate 3 is WY111BR, produced by Lihuayi, with a melt flow rate (ISO1133-2011) of 12.4 g / 10 min at 300° C. and a load of 1.2 kg, and a non-Newtonian index of 0.37;

[0084] The polycarbonate 4 is 2220, produced by Wanhua Chemical, with a melt flow rate of 19.8 g / 10 min at 300°C and a load of 1.2 kg, and a non-Newtonian index of 0.56;

[0085] The polycarbonate 5 is FB2560, produced by Idemitsu, Japan, with a melt flow rate (ISO1133-2011) of 2.83 g / 10 min at 300° C. and a load of 1.2 kg, and a non-Newtonian index of 0.28;

[0086] The polycarbonate 6 is 3026, produced by Mitsubishi of Japan, with a melt flow rate (ISO1133-2011) of 2.17 g / 10 min at 300° C. and a load of 1.2 kg, and a non-Newtonian index of 0.21;

[0087] The ABS resin 1 is ABS3504, produced in Shanghai Gaoqiao, and has a melt index of 7.8 g / 10 min at 220° C. and 10 kg load according to ISO 1133-2011;

[0088] The ABS resin 2 is KF730-PC, produced by Liaoning Jinfa, and has a melt index of 20.7 g / 10 min at 220°C and 10 kg load according to ISO 1133-2011;

[0089] The toughening agent 1 is M521, MBS, produced by Kaneka, Japan, and has a melt index of 1.3 g / 10 min at 300° C. and 1.2 kg load according to ISO1133-2011;

[0090] The toughening agent 2 is S2501, MMA grafted silicone rubber, produced by Mitsubishi Chemical of Japan, with a melt index of 4.4 g / 10 min at 300°C and 1.2 kg load according to ISO1133-2011;

[0091] The flame retardant is a halogen-free phosphorus flame retardant phosphate 1,3-ylidenephosphorus tetrakis (2,6-dimethyl) ester, with a phosphorus content of 9.1 wt%, and is a PX200 product produced by Daihachi, Japan.

[0092] The anti-dripping agent is commercially available polytetrafluoroethylene;

[0093] The processing fluidity improver 1 is P-570 produced by Mitsubishi Chemical, an acrylate copolymer polymethyl methacrylate, with a weight average molecular weight of 500,000;

[0094] The processing fluidity improver 2 is P-551 produced by Mitsubishi Chemical, an acrylate copolymer polymethyl methacrylate, with a weight average molecular weight of 1500000;

[0095] The processing fluidity improver 3 is P-530 produced by Mitsubishi Chemical, an acrylate copolymer polymethyl methacrylate, with a weight average molecular weight of 2800000;

[0096] The processing fluidity improver 4 is PMMA V150 produced by Arkema, France, an acrylate copolymer polymethyl methacrylate with a weight average molecular weight of 200,000;

[0097] The processing fluidity improver 5 is EMI 100 produced by Shanghai Rizhisheng, a styrene-acrylonitrile copolymer with a weight-average molecular weight of 1800;

[0098] The processing fluidity improver 6 is C100 produced by Wuhan Hyperbranched Resin Technology, with a weight-average molecular weight of 3200.

[0099] The processing fluidity improver 7 is GPPS123P produced by Shanghai Secco, polystyrene, with a weight average molecular weight of 500,000.

[0100] Unless otherwise specified, the components and raw materials used in the examples and comparative examples of the present application are all commercially available raw materials, and the components and raw materials used in each parallel experiment are all of the same kind.

[0101] Table 1

[0102] Table 2

[0103] In order to verify the performance of the polycarbonate composition described in this application, the products prepared in each embodiment and comparative example were subjected to the following performance tests. The specific steps are as follows:

[0104] (1) Room temperature thin-wall notched impact strength test: According to ASTM D256, a 1.5 mm × 12.7 mm × 64 mm test plate with a V-notch was injection molded. The pendulum energy was 5.5 kJs. The test environment temperature was room temperature (25°C) and the humidity was 50%. After 48 hours of conditioning, the impact test was performed. The test values ​​of 5 pieces were recorded and the average value was calculated as the final evaluation result.

[0105] (2) 1.5mm flame retardant grade test: tested and determined according to UL94-2023 standard;

[0106] (3) Spiral length test: The injection molding temperature is fixed at 260°C, the injection pressure is 50%, the injection speed is 50%, the holding time is 3s, the cooling time is 5s, and the mold temperature is 80°C. After 20 consecutive injections, the spiral length scale from the 15th to the 20th mold is read and recorded, and the average value is calculated as the final result. Under the same test conditions, the longer the spiral length, the better the injection molding processability and the more suitable it is for thin-wall injection molding applications.

[0107] (4) Appearance performance test: Each product was injection molded with a fixed injection temperature of 280°C, injection pressure of 90%, injection speed of 90%, holding time of 3s, cooling time of 5s, mold temperature of 80°C, and a 1.5mm large plate splash mold. The defects at the end and on the surface of the large plate were observed. When the large plate had no defects or only sporadic short defects appeared at the end and the number was less than 5, it was rated as Level 1; when sporadic defects appeared on the large plate and at the end and the number was between 5 and 15, it was rated as Level 2; when sporadic defects appeared on the large plate and at the end and the number was between 15 and 25, it was rated as Level 3; when the defects were clustered into blocks or the surface was foggy, it was rated as Level 4.

[0108] The test results are shown in Tables 3 and 4.

[0109] Table 3

[0110] Table 4

[0111] As can be seen from Tables 3 and 4, the polycarbonate composition of the present invention has a spiral length of more than 280 and high processing fluidity, making it very suitable for processing thin-walled parts used in some portable electronic products. In the thin-walled state, it can reach at least 550 J / m 2 The notched impact strength and flame retardancy at 1.5 mm can all reach V-0, and the appearance grade can reach grade 2 or above, with excellent comprehensive performance. Among the components of the product described in this application, the processing fluidity improver is extremely important. As shown in Comparative Examples 3 to 5, if some low molecular weight acrylate copolymers or the fluidity improving components used in the prior art are used, they cannot achieve the same improvement effect. However, according to Comparative Example 1, Examples 12 to 13, Example 1, Examples 14 to 16 and Comparative Example 2, it can be seen that as the amount of processing fluidity improver added gradually increases, the processing fluidity of the product is significantly improved, but if too much is added, the degree of entanglement of the alloy molecules in the product is too high, and the spiral length and appearance performance of the product will be significantly deteriorated, and need to be maintained within an appropriate range; further, when the number of added portions of the processing fluidity improver is maintained at 1 to 4 parts, preferably 2 to 3 parts, the comprehensive performance of the product is best. On the other hand, it can be seen from Example 1, Examples 10-11, and Comparative Examples 3-6 that the weight-average molecular weight of the acrylate copolymer must be above 500,000 for the product to achieve the desired effect, and when it is maintained within the range of 500,000 to 1,500,000, the overall performance is even better. On the other hand, it can be seen from Example 1 and Examples 5-8 that when the non-Newtonian index of the polycarbonate in the product is maintained within the range of ≤0.5 and the melt flow rate is maintained within a certain range, the product can achieve both optimal processing fluidity and appearance performance, and there is a certain difference between the non-Newtonian index and the melt flow rate properties of the polycarbonate.

[0112] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application and are not intended to limit the scope of protection of the present application. Although the present application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present application may be modified or replaced by equivalents without departing from the essence and scope of the technical solutions of the present application.

Claims

1. A polycarbonate composition, characterized in that The composition comprises the following components in parts by weight: 60-90 parts of polycarbonate, 10-50 parts of ABS (terpolymer of acrylonitrile-butadiene-styrene) resin, and 0.5-5 parts of processing fluidity improver; The processing fluidity improver is an acrylic acid ester copolymer with a weight average molecular weight of ≥500,000.

2. The polycarbonate composition according to claim 1, characterized in that The weight average molecular weight of the acrylic ester copolymer is 500,000 to 4,500,000.

3. The polycarbonate composition according to claim 1, wherein The non-Newtonian index of the polycarbonate is 0.15 to 0.83; preferably, the non-Newtonian index of the polycarbonate is 0.2 to 0.

56.

4. The polycarbonate composition according to claim 1, wherein The polycarbonate has a melt flow rate of 0.6 to 70 g / 10 min at 300° C. and a load of 1.2 kg according to ISO 1133-2011; preferably, the polycarbonate has a melt index of 2 to 26 g / 10 min at 300° C. and a load of 1.2 kg according to ISO 1133-2011.

5. The polycarbonate composition according to claim 1, wherein The components also include the following components in parts by weight: 0.1 to 10 parts of a toughening agent, 0.01 to 5 parts of a flame retardant, and 0.1 to 5 parts of an anti-dripping agent.

6. The polycarbonate composition according to claim 5, characterized in that The toughening agent is at least one of SAN grafted PB rubber (polybutadiene rubber grafted with styrene-acrylonitrile copolymer), MMA (methyl methacrylate) grafted silicone rubber, SAN (styrene-acrylonitrile copolymer) grafted silicone rubber, SEBS (styrene-ethylene-butylene-styrene block copolymer), and MBS (terpolymer of methyl methacrylate-butadiene-styrene).

7. The polycarbonate composition according to claim 1, wherein The weight proportion of the processing fluidity improver is 1 to 4 parts.

8. The polycarbonate composition according to claim 1, wherein The acrylic ester copolymer is polymethyl methacrylate.

9. The method for preparing the polycarbonate composition according to any one of claims 1 to 8, characterized in that: The following steps are involved: After the components are uniformly mixed, they are melt-extruded and granulated in a twin-screw extruder to obtain the polycarbonate composition.

10. Use of the polycarbonate composition according to any one of claims 1 to 8 in the preparation of thin-walled portable electronic products.

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