Polycarbonate composite material and preparation method therefor, polycarbonate antistatic sheet, and polycarbonate antistatic carrier tape

Abstract

The present application discloses a polycarbonate composite material and a preparation method therefor, a polycarbonate antistatic sheet, and a polycarbonate antistatic carrier tape. In the polycarbonate composite material, polycarbonate is used as a main component, and is used in conjunction with carbon nanotubes, a compound dispersant, an antioxidant, a lubricant, and a toughening agent, the carbon nanotubes are used as conductive agents to replace conventional conductive materials, ensuring that no die ash will be generated in the process of manufacturing a sheet or a carrier tape, and cleanliness is high, and use of a compound dispersant system containing a mixture of a hydroxyl-terminated organic lubricant and an inorganic dispersant can improve the dispersion effect of the carbon nanotubes in the polycarbonate material, reduce surface resistivity, and ensure that the material has uniform conductivity; in addition, the toughening agent can improve mechanical properties, the antioxidant and the lubricant can ensure stable material properties, processing is easy, and the polycarbonate composite material having a low crystal point, uniform electric conduction and high cleanliness is obtained, thus facilitating wide application.

Description

Polycarbonate composite material and preparation method thereof, polycarbonate antistatic sheet and polycarbonate antistatic carrier tape Technical Field

[0001] The present application relates to the field of semiconductor packaging technology, and in particular to a polycarbonate composite material and a preparation method thereof, a polycarbonate antistatic sheet, and a polycarbonate antistatic carrier tape. Background Art

[0002] Plastic sheet is a semi-finished sheet material used in electronics packaging. This sheet is manufactured into carrier tape through a blister or slicing process. Carrier tape is a packaging product used in electronics packaging. It is used with cover tape to hold electronic components such as chips, resistors, capacitors, transistors, and diodes within its cavities (also known as pockets). The cover tape is then sealed over the carrier tape to create a closed package, protecting the components from contamination and damage during transport.

[0003] Currently, most sheets used to mount semiconductor chips use polycarbonate (PC) as a base material, with conductive carbon black and conductive graphite added as conductive agents at a dosage of 10%-25%. When the conductive agent dosage is less than 10%, the required surface resistivity cannot be achieved. Conversely, when it exceeds 25%, strength and fluidity decrease, and the carbon black can cause shedding, easily generating carbon dust. This carbon dust falls onto the sheet or carrier tape, further contaminating and damaging semiconductor components.

[0004] However, composite materials made from polycarbonate and a conductive agent (conductive carbon black or conductive graphite) often present the following challenges when used as sheet materials: The addition of large amounts of conductive agent can lead to poor fluidity during processing; mold dust is generated during sheet or carrier tape extrusion, which can easily contaminate the sheet or carrier tape during production; carbon dust is easily lost due to friction, which can contaminate electronic components; and excessive sulfur content in conductive carbon black in semiconductor sheets can cause oxidation, resulting in chip blackening and even scrap. Therefore, there is an urgent need to provide a composite material with a low surface crystal point, uniform conductivity, and high purity as a raw material for sheet production, so that the resulting sheets can be widely used in packaging products in the semiconductor packaging field. Technical issues

[0005] One of the purposes of the embodiments of the present application is to provide a polycarbonate composite material and a preparation method thereof, a polycarbonate antistatic sheet and a polycarbonate antistatic carrier, aiming to solve the problems of low purity and uneven conductivity of polycarbonate composite materials in the prior art. Technical Solutions

[0006] To solve the above technical problems, the technical solutions adopted in the embodiments of the present application are:

[0007] In a first aspect, a polycarbonate composite material is provided, which includes the following components in percentage by weight, based on the total weight of the polycarbonate composite material as 100%: 70-97.2 wt% of polycarbonate; 1-10 wt% of carbon nanotubes; 0.2-3 wt% of a compounded dispersant; 0.1-0.5 wt% of an antioxidant; 0.5-2 wt% of a lubricant; and 1-2 wt% of a toughening agent; wherein the compounded dispersant is selected from a mixture of an organic lubricant containing terminal hydroxyl groups and an inorganic dispersant.

[0008] In some embodiments, in the compound dispersant, the mass ratio of the organic lubricant containing terminal hydroxyl groups to the inorganic dispersant is 1:1-1.2.

[0009] In some embodiments, the organic lubricant containing terminal hydroxyl groups includes Wuhan hyperbranched HBP-160.

[0010] In some embodiments, the inorganic dispersant includes at least one of calcium carbonate, barium sulfate, talc, boron nitride, silicon dioxide, alum, titanium dioxide, calcium oxide, magnesium oxide, carbon black, and mica powder.

[0011] In some embodiments, the particle size of the inorganic dispersant is 5000-10000 mesh.

[0012] In some embodiments, the carbon nanotubes include acidified carbon nanotubes; the diameter of the carbon nanotubes is 2-20 nm; the length of the carbon nanotubes is 2-50 μm; the aspect ratio of the carbon nanotubes is 1000-5000:1; and the specific surface area of ​​the carbon nanotubes is 200-280 m 2 / g.

[0013] In some embodiments, the polycarbonate is selected from a combination of a low viscosity polycarbonate having a melt index of 20 to 30 g / 10 min and a high viscosity polycarbonate having a melt index of 5 to 8 g / 10 min.

[0014] In some embodiments, in the polycarbonate, the mass ratio of the low-viscosity polycarbonate to the high-viscosity polycarbonate is 2-3:7.

[0015] In some embodiments, the antioxidant comprises a phosphate antioxidant.

[0016] In some embodiments, the lubricant includes at least one of pentaerythritol stearate and N,N'-ethylenebis-12-hydroxystearamide.

[0017] In some embodiments, the toughening agent includes at least one of a terpolymer of methyl methacrylate-butadiene-styrene, a polyolefin elastomer, and an ethylene-methyl acrylate copolymer.

[0018] In some embodiments, the phosphate antioxidant includes bis(2,4-dicumylphenyl)pentaerythritol diphosphite.

[0019] In a second aspect, a method for preparing a polycarbonate composite material is provided, comprising the following steps:

[0020] Provide raw materials of various components according to polycarbonate composite materials;

[0021] The compound dispersant, antioxidant, lubricant and toughening agent are dispersed separately and then mixed to obtain an additive mixture;

[0022] The polycarbonate, carbon nanotubes and an auxiliary agent mixture are melt-mixed to obtain a polycarbonate composite material.

[0023] In some embodiments, the melt mixing process includes: performing the melt mixing process using a twin-screw extruder under double vacuum conditions.

[0024] In some embodiments, the conditions for melt mixing using a twin-screw extruder include: a melt temperature of 310-325°C; a main engine speed of 400-500 rpm; an extrusion temperature from zone 1 to zone 2 of 200-260°C, an extrusion temperature from zone 3 to zone 6 of 250-260°C, an extrusion temperature from zone 7 to zone 10 of 230-250°C, and a temperature from zone 11 to the die head of 240-260°C.

[0025] In some embodiments, the preparation method further comprises: pulling out the melt obtained after the melt mixing process through a shaping die at a constant moving speed, cooling it in a water tank, and pelletizing it after air drying to obtain a polycarbonate composite material.

[0026] In a third aspect, a polycarbonate antistatic sheet is provided, including a polycarbonate composite material or a polycarbonate composite material prepared by a method for preparing a polycarbonate composite material.

[0027] In a fourth aspect, a polycarbonate antistatic carrier tape is provided, which is prepared from a polycarbonate antistatic sheet. Beneficial effects

[0028] The beneficial effects of a polycarbonate composite material provided in an embodiment of the present application are as follows: the polycarbonate composite material provided in the present application uses polycarbonate as a main component, and is used in conjunction with carbon nanotubes, a compound dispersant, an antioxidant, a lubricant and a toughening agent. Carbon nanotubes are used as a conductive agent instead of traditional conductive materials such as conductive carbon black, ensuring that mold dust is not generated during the production of sheets or carriers, and the material cleanliness is high. The use of a compound dispersant system containing a mixture of an organic lubricant and an inorganic dispersant containing terminal hydroxyl groups can help improve the dispersion effect of carbon nanotubes in the polycarbonate material, reduce the surface resistivity, and ensure that the material has uniform conductivity; avoid the uneven surface of the obtained sheet or carrier resulting in uneven conductivity; in addition, the toughening agent can improve the overall mechanical properties of the polycarbonate composite material, and the antioxidant and lubricant can ensure that the material properties are stable and easy to process; therefore, the present application uses polycarbonate as a main component, and by using carbon nanotubes and a compound dispersant system to modify polycarbonate, a polycarbonate composite material with a low crystal point, uniform conductivity and high cleanliness is obtained, which is conducive to wide application.

[0029] The beneficial effect of a preparation method of a polycarbonate composite material provided in an embodiment of the present application is that: the preparation method of the polycarbonate composite material provided in the present application includes first dispersing each auxiliary agent to obtain an auxiliary agent mixture, and then mixing it with polycarbonate and carbon nanotubes and melting it to obtain a polycarbonate composite material; the preparation method is simple and easy to operate, and can ensure that the various components are evenly dispersed, and ensure that the obtained polycarbonate composite material has a smooth surface and uniform conductivity. Therefore, the preparation method is suitable for industrial applications.

[0030] The beneficial effect of a polycarbonate antistatic sheet provided in an embodiment of the present application is that: the polycarbonate antistatic sheet provided in the present application includes the polycarbonate composite material provided in the first aspect above or the polycarbonate composite material prepared by the polycarbonate composite material preparation method provided in the second aspect above. Therefore, the obtained polycarbonate antistatic sheet has excellent antistatic properties, low crystal point, uniform conductivity, and high purity, which is conducive to its wide application in the field of electronic packaging.

[0031] The beneficial effect of a polycarbonate antistatic carrier provided in an embodiment of the present application is that: the polycarbonate antistatic carrier provided in the present application is prepared by processing the above-mentioned polycarbonate antistatic sheet, and the obtained polycarbonate antistatic carrier has a low surface crystal point, uniform conductivity, high cleanliness and high mechanical properties, good recyclability, and reuse does not affect the conductive properties, and has good application in electronic packaging materials. Modes for Carrying Out the Invention

[0032] In order to make the purpose, technical solutions and advantages of this application more clear, the following is a further detailed description of this application in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit this application.

[0033] In a first aspect, an embodiment of the present application provides a polycarbonate composite material, which, based on the total weight of the polycarbonate composite material being 100%, comprises the following components in percentage by weight: 70-97.2 wt% of polycarbonate; 1-10 wt% of carbon nanotubes; 0.2-3 wt% of a compounded dispersant; 0.1-0.5 wt% of an antioxidant; 0.5-2 wt% of a lubricant; and 1-2 wt% of a toughening agent; wherein the compounded dispersant is selected from a mixture of an organic lubricant containing terminal hydroxyl groups and an inorganic dispersant.

[0034] The polycarbonate composite material provided in the first aspect of the embodiment of the present application uses polycarbonate as the main component, and is used in conjunction with carbon nanotubes, compound dispersants, antioxidants, lubricants and toughening agents. Carbon nanotubes are used as conductive agents instead of traditional conductive carbon black and other conductive materials to ensure that mold ash is not generated in the process of manufacturing sheets or carriers, and the material cleanliness is high. The use of a compound dispersant system containing a mixture of an organic lubricant and an inorganic dispersant containing terminal hydroxyl groups can help improve the dispersion effect of carbon nanotubes in polycarbonate materials, reduce surface resistivity, ensure that the material has uniform conductivity, and avoid uneven conductivity caused by the uneven surface of the obtained sheet or carrier; in addition, the toughening agent can improve the overall mechanical properties of the polycarbonate composite material, and the antioxidant and lubricant can ensure that the material properties are stable and easy to process; therefore, the present application uses polycarbonate as the main component, and modifies polycarbonate by using carbon nanotubes and a compound dispersant system to obtain a polycarbonate composite material with low crystal point, uniform conductivity and high cleanliness, which is conducive to wide application.

[0035] This application uses polycarbonate as the base material. Based on the total weight of the polycarbonate composite material being 100%, the amount of polycarbonate added is 70 to 97.2 wt%. In some specific embodiments, the amount of polycarbonate added includes but is not limited to 70 wt%, 71 wt%, 72 wt%, 73 wt%, 74 wt%, 75 wt%, 76 wt%, 77 wt%, 78 wt%, 79 wt%, 80 wt%, 81 wt%, 82 wt%, 83 wt%, 84 wt%, 85 wt%, 86 wt%, 87 wt%, 88 wt%, 89 wt%, 90 wt%, 91 wt%, 92 wt%, 93 wt%, 94 wt%, 95 wt%, 96 wt%, and 97 wt%.

[0036] In some embodiments, the polycarbonate is selected from a combination of a low-viscosity polycarbonate having a melt index of 20-30 g / 10 min and a high-viscosity polycarbonate having a melt index of 5-8 g / 10 min. The low-viscosity polycarbonate and the high-viscosity polycarbonate are blended together to facilitate neutralization between the two materials, thereby improving the mechanical strength, heat aging resistance, solvent resistance, and stability of the polycarbonate composite material. More importantly, it enhances processing fluidity.

[0037] In some embodiments, the mass ratio of the low-viscosity polycarbonate to the high-viscosity polycarbonate in the polycarbonate is 2 to 3:7. In some specific embodiments, the mass ratio of the low-viscosity polycarbonate to the high-viscosity polycarbonate in the polycarbonate is 3:7.

[0038] Since the conductive agent used in most polycarbonate composite substrates is conductive carbon black or conductive graphite, the addition amount is 10%-25%. When the conductive agent is added below 10%, the required surface resistivity cannot be achieved. Conversely, when the conductive agent exceeds 25%, the strength and fluidity are reduced, and the carbon black will cause shedding, which easily produces carbon dust. The carbon dust falls on the sheet or carrier, contaminating and damaging semiconductor components. Therefore, to ensure that the polycarbonate composite material has excellent conductivity and high surface crystallinity, this application uses carbon nanotubes as the conductive agent.

[0039] Furthermore, the amount of carbon nanotubes added is 1-10 wt % based on the total weight of the polycarbonate composite material as 100%. Due to their extremely high specific surface area and specific strength, carbon nanotubes can form a conductive network when mixed with the polycarbonate substrate. When used in place of conductive graphite or conductive carbon black, the amount added is less than that of conductive graphite or conductive carbon black, while achieving the same conductive effect. Furthermore, the carbon nanotubes have high chemical stability and do not generate carbon powder during use, thus resolving the issue of carbon powder generated by conductive carbon black or conductive graphite falling onto the sheet or carrier tape, contaminating and damaging semiconductor components. Using carbon nanotubes as a conductive agent ensures that mold dust is not generated during the production of the sheet or carrier tape, resulting in high material cleanliness and excellent conductive properties.

[0040] In some specific embodiments, the added amount of carbon nanotubes includes but is not limited to 1 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt%, 6 wt%, 7 wt%, 8 wt%, 9 wt%, and 10 wt%.

[0041] In some embodiments, the carbon nanotubes include acidified carbon nanotubes.

[0042] In some specific embodiments, the carbon nanotubes include but are not limited to at least one of single-walled carbon nanotubes, multi-walled carbon nanotubes, and arrayed carbon nanotubes.

[0043] In some embodiments, the carbon nanotubes are selected from multi-walled carbon nanotubes, and the multi-walled carbon nanotubes are subjected to an acidic pretreatment to obtain acidic multi-walled carbon nanotubes. The selection of multi-walled carbon nanotubes can increase the specific surface area of ​​the carbon nanotubes, thereby improving the electrical conductivity of the material.

[0044] In some specific embodiments, acidic multi-walled carbon nanotubes are obtained by subjecting the multi-walled carbon nanotubes to an acidic pretreatment, wherein the acidic pretreatment comprises soaking the multi-walled carbon nanotubes in a concentrated sulfuric acid solution for 15 to 30 minutes. Since polycarbonate itself is a weakly alkaline substance, providing acidic carbon nanotubes for compounding facilitates neutralization with the polycarbonate, ensuring that bubbles are not generated during the production process and that the resulting product has a smooth surface.

[0045] In some embodiments, the carbon nanotubes have a diameter of 2 to 20 nm. If the carbon nanotubes have a diameter that is too small, they may not disperse well during mixing and may agglomerate, resulting in bumps and pits on the composite material surface and uneven conductivity. In some specific embodiments, the carbon nanotubes have diameters including, but not limited to, 2 nm, 4 nm, 6 nm, 8 nm, 10 nm, 12 nm, 14 nm, 16 nm, 18 nm, and 20 nm.

[0046] In some embodiments, the carbon nanotubes are 2 to 50 μm in length. If the carbon nanotubes are too short, mixing them into the matrix will not be conducive to forming a conductive network, affecting the conductivity of the composite material. If the carbon nanotubes are too long, they will not be easily dispersed evenly, which may result in an uneven surface of the resulting composite material, making it difficult to use. In some specific embodiments, the length of the carbon nanotubes includes, but is not limited to, 2 μm, 5 μm, 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm, and 50 μm.

[0047] In some embodiments, the carbon nanotubes have an aspect ratio of 1000 to 5000:1. Controlling the aspect ratio of the added carbon nanotubes to 1000 to 5000:1 ensures excellent conductivity of the carbon nanotubes, ensuring that the added amount is less than that of conductive graphite or conductive carbon black while achieving the same conductive effect. In some specific embodiments, the aspect ratio of the carbon nanotubes is 1000:1.

[0048] In some embodiments, the specific surface area of ​​the carbon nanotubes is 200-280 m 2 / g. Controlling the specific surface area of ​​carbon nanotubes to a moderate level is beneficial to ensuring that adding a small amount of carbon nanotubes can ensure high electrical conductivity and good stability, which can better improve the performance of polycarbonate. In some specific embodiments, the specific surface area of ​​carbon nanotubes includes but is not limited to 200 m 2 / g, 210 m 2 / g, 220 m 2 / g, 230m 2 / g, 240m 2 / g, 250m 2 / g, 260m 2 / g, 270 m 2 / g, 280 m 2 / g.

[0049] However, because carbon nanotubes are nanometer-sized, they exhibit many nanometer-sized effects. When the size of the provided carbon nanotubes reaches the nanometer scale, their agglomeration effect increases significantly, the mutual attraction of the agglomerate particles also increases significantly, and the difficulty of dispersion becomes greater, exhibiting a strong agglomeration effect at the nanometer scale. Therefore, during use, because carbon nanotubes easily form agglomerates, the surface of the resulting composite material may form convex points and concave portions, which may affect the smoothness of the material. Therefore, the polycarbonate composite material provided by the present application provides a compound dispersant for mixing treatment to address the characteristic that carbon nanotubes easily aggregate, thereby ensuring that the carbon nanotubes can be evenly dispersed.

[0050] Furthermore, the amount of the compounded dispersant added is 0.2 to 3 wt% based on the total weight of the polycarbonate composite material as 100%. The compounded dispersant is selected from a mixture of an organic lubricant containing terminal hydroxyl groups and an inorganic dispersant. Using a compounded dispersant system comprising a mixture of an organic lubricant containing terminal hydroxyl groups and an inorganic dispersant can improve the dispersion of carbon nanotubes in the polycarbonate material, reduce surface resistivity, ensure uniform conductivity of the material, and avoid uneven conductivity caused by uneven surfaces of the resulting sheet or carrier tape.

[0051] In some specific embodiments, the added amount of the compound dispersant includes but is not limited to 0.2 wt%, 0.4 wt%, 0.6 wt%, 0.8 wt%, 1.0 wt%, 1.2 wt%, 1.4 wt%, 1.6 wt%, 1.8 wt%, 2.0 wt%, 2.2 wt%, 2.4 wt%, 2.6 wt%, 2.8 wt%, and 3.0 wt%.

[0052] Among them, organic lubricants containing terminal hydroxyl groups refer to lubricants that have organic functional groups grafted onto polymers and integrate the functions of dispersion, compatibility, coupling, and lubrication, and generally have high temperature resistance. The addition of organic lubricants containing terminal hydroxyl groups has a strong affinity for inorganic fillers, enabling them to be fully activated and modified, destroying and preventing the agglomeration of inorganic matter, thereby more evenly dispersing them into the polymer. At the same time, it relies on strong interfacial bonding to achieve the effect of toughening and strengthening. In addition, the provided organic lubricant containing terminal hydroxyl groups has an initial decomposition temperature of 340°C and does not decompose to produce small molecules during the preparation process of polycarbonate composite materials and subsequent product processing.

[0053] In some embodiments, the organic lubricant containing terminal hydroxyl groups includes Wuhan hyperbranched HBP-160.

[0054] The compound dispersant includes not only an organic lubricant containing terminal hydroxyl groups but also an inorganic dispersant. The inorganic dispersant can generate greater surface energy during the dispersion process, promote the dispersion of carbon nanotubes, and help maintain the stability of the material and improve its temperature resistance.

[0055] In some embodiments, the inorganic dispersant includes at least one of calcium carbonate, barium sulfate, talc, boron nitride, silicon dioxide, alum, titanium dioxide, calcium oxide, magnesium oxide, carbon black, and mica powder. In some specific embodiments, the inorganic dispersant is selected from talc.

[0056] In some embodiments, the particle size of the inorganic dispersant is 5000-10000 mesh. In some specific embodiments, the particle size of the inorganic dispersant includes but is not limited to 5000 mesh, 6000 mesh, 7000 mesh, 8000 mesh, 9000 mesh, and 10000 mesh.

[0057] In some embodiments, the inorganic dispersant is first subjected to a separate dispersion treatment in order to break up the solid particles condensed inside the inorganic dispersant to facilitate mixing with other components.

[0058] In some embodiments, the mass ratio of the organic lubricant containing terminal hydroxyl groups to the inorganic dispersant in the compound dispersant is 1:1 to 1.2. The purpose of controlling the mass ratio of the organic lubricant containing terminal hydroxyl groups to the inorganic dispersant is to improve the dispersibility of the carbon nanotubes.

[0059] Furthermore, the polycarbonate composite material may include 0.1 to 0.5 wt% of an antioxidant, based on the total weight of the polycarbonate composite material as 100%. The addition of the antioxidant helps to prevent aging caused by high-temperature processing during the preparation and use of the material. In some specific embodiments, the amount of antioxidant added includes, but is not limited to, 0.1 wt%, 0.2 wt%, 0.3 wt%, 0.4 wt%, and 0.5 wt%.

[0060] In some embodiments, the antioxidant includes a phosphate antioxidant. The selected phosphate antioxidant exhibits good high-temperature resistance, high molecular weight, low volatility at high temperatures, resistance to high-temperature degradation, stability during extrusion, and ease of processing. In some specific embodiments, the phosphate antioxidant includes but is not limited to bis(2,4-dicumylphenyl)pentaerythritol diphosphite.

[0061] Furthermore, the polycarbonate composite material further comprises 0.5-2 wt% of a lubricant, based on the total weight of the polycarbonate composite material being 100%. In some specific embodiments, the amount of the lubricant added includes, but is not limited to, 0.5 wt%, 1 wt%, 1.2 wt%, 1.4 wt%, 1.6 wt%, 1.8 wt%, and 2 wt%.

[0062] In some embodiments, the lubricant includes at least one of pentaerythritol stearate and N,N'-ethylenebis-12-hydroxystearamide. Preferably, N,N'-ethylenebis-12-hydroxystearamide is compounded with a high-temperature-resistant lubricant containing terminal hydroxyl groups to ensure that the polycarbonate composite material does not precipitate or migrate when processed into sheets at high temperatures. This prevents the sheets from generating gas and migrating due to high-temperature decomposition, which could result in pitting on the surface of the finished product.

[0063] In some specific embodiments, the lubricant is selected from a mixture of pentaerythritol stearate and N,N'-ethylenebis-12-hydroxystearamide in a mass ratio of 1:1.

[0064] Furthermore, the polycarbonate composite material may include 1 to 2 wt% of a toughening agent, based on the total weight of the polycarbonate composite material as 100%. The addition of the toughening agent can improve the overall mechanical properties of the polycarbonate composite material. In some specific embodiments, the amount of toughening agent added includes, but is not limited to, 1 wt%, 1.2 wt%, 1.4 wt%, 1.6 wt%, 1.8 wt%, and 2 wt%.

[0065] In some embodiments, the toughening agent includes at least one of a terpolymer of methyl methacrylate-butadiene-styrene, a polyolefin elastomer, and an ethylene-methyl acrylate copolymer.

[0066] A second aspect of the present invention provides a method for preparing a polycarbonate composite material, comprising the following steps:

[0067] S01 provides raw materials for each component according to the polycarbonate composite material;

[0068] S02 The compound dispersant, antioxidant, lubricant and toughening agent were dispersed and mixed to obtain an additive mixture;

[0069] S03. Melt-mixing the polycarbonate, carbon nanotubes, and additive mixture to obtain a polycarbonate composite material.

[0070] The preparation method of the polycarbonate composite material provided in the second aspect of the embodiment of the present application includes first dispersing each auxiliary agent to obtain an auxiliary agent mixture, and then mixing it with polycarbonate and carbon nanotubes and melting it to obtain a polycarbonate composite material; the preparation method is simple and easy to operate, and can ensure that the various components are evenly dispersed, and ensure that the obtained polycarbonate composite material has a smooth surface and uniform conductivity. Therefore, the preparation method is suitable for industrial applications.

[0071] In step S01, various raw materials are provided according to the polycarbonate composite material. The selection and addition amount of the various raw materials of the polycarbonate composite material are as described above, and will not be repeated here to save space.

[0072] In step S02, the compound dispersant, antioxidant, lubricant and toughening agent are dispersed separately and then mixed to obtain an additive mixture.

[0073] In some embodiments, the dispersion treatment includes: stirring the inorganic dispersant in the compound dispersant at high speed in a high-speed stirrer for a first dispersion treatment to obtain a first dispersion; mixing the organic lubricant containing terminal hydroxyl groups, lubricant, antioxidant, toughening agent and the first dispersion in the compound dispersant, and then stirring at high speed in a high-speed stirrer for a second dispersion treatment to obtain an additive mixture.

[0074] In some embodiments, the speed of the medium-high speed stirring is 100-300 r / min, the purpose of which is to ensure that the granular additives can be completely dispersed, which is conducive to uniform mixing of the components.

[0075] In some embodiments, the first dispersion treatment lasts for 10 to 15 minutes. Since the inorganic dispersant particles are dense and relatively solid, a longer dispersion treatment time is required to ensure that the inorganic dispersant is loose inside, which is conducive to uniform mixing with other components.

[0076] In some embodiments, the second dispersion treatment lasts for 2 to 5 minutes. The second dispersion treatment is mainly used to mix the components uniformly.

[0077] In step S03, the polycarbonate, carbon nanotubes and the additive mixture are melt-mixed to obtain a polycarbonate composite material.

[0078] In some embodiments, the melt mixing process includes: performing the melt mixing process using a twin-screw extruder under double vacuum conditions. The double vacuum conditions can remove excess small molecule impurities and prevent the small molecule impurities from decomposing into gases at the rear end to form pits.

[0079] In some embodiments, the conditions for melt mixing using a twin-screw extruder include: a melt temperature of 310-325°C; a main engine speed of 400-500 rpm; an extrusion temperature from zone 1 to zone 2 of 200-260°C, an extrusion temperature from zone 3 to zone 6 of 250-260°C, an extrusion temperature from zone 7 to zone 10 of 230-250°C, and a temperature from zone 11 to the die head of 240-260°C.

[0080] In some embodiments, a medium-strength screw combination is used for processing, mainly using multiple shear blocks at the front end of the screw combination, and compounding several shear blocks to ensure that the carbon nanotubes are well dispersed in the twin-screw extruder; at the same time, the strength of the screw combination cannot be too strong, otherwise the main substrate polycarbonate will be carbonized, and small particles will be generated when the sheet is extruded at the rear end, affecting the use. The rear end of the screw combination needs to be weakened, and more mixing blocks should be added to fully ensure the plasticizing time of the plastic in the screw.

[0081] Specific examples of screw combinations are as follows:

[0082] The front-end combination order of the screw assembly is K30° / 5 / 64, K45° / 5 / 56, K45° / 5 / 44, 44 / 44, K45° / 4 / 56, K60° / 4 / 64, K60° / 6 / 44, K90° / 5 / 56, 44 / 44, K45° / 4 / 56, K60° / 4 / 44, K90° / 5 / 56, 44 / 44L, and the rear-end screw combination order is K30° / 6 / 56, K45° / 5 / 56, K60° / 5 / 56, 56 / 56, C18, C18, 44 / 44, K60° / 5 / 56, K45° / 5 / 36 L, 44 / 44, C18, C18, 56 / 56, K60° / 5 / 56.

[0083] The screw assembly described above is divided into conveying elements, shearing elements, and special elements (such as tensile elements, dispersing element toothed discs, and transition pieces). The components are as follows: The conveying element consists of a lead and a length, with forward and reverse directions indicated by two digits, while reverse directions are indicated by the two digits followed by an "L." For example, in a designation like 44 / 44, the first "44" represents the lead (i.e., the axial length of the material traveling one revolution around the screw thread), and the second "44" represents the length of the screw element (i.e., the axial length of the element).

[0084] Common components of conveyor blocks are:

[0085] 128 / 128,96 / 96,72 / 72,64 / 64,56 / 56,44 / 44,48 / 48,32 / 32,22 / 22,72 / 36,44 / 22L,22 / 11L.

[0086] Shear elements are composed of multiple shear blades kneaded together, ranging from 4 to 7 blades with varying thicknesses. Different kneading types are selected based on specific needs. Thicker blades provide greater distribution, while thinner blades provide greater dispersion. A larger angle between blades increases shear capacity, and this is also categorized as positive or negative. This is expressed as: K angle / number of blades / element length. For the reverse direction, it's expressed as K angle / number of blades / element length L. For example, a shear block model might be: K90° / 5 / 56L, where 90 indicates the kneading angle of the blades, 5 indicates the number of blades, 56 indicates the length, and L indicates left-hand direction.

[0087] Special shearing elements include toothed discs and stretching blocks. The toothed disc mainly plays a dispersing role and is usually used in the homogenizing section at the rear end of the screw. The thickness is expressed as C, such as C18, which refers to a toothed disc with a thickness of 18mm.

[0088] In some embodiments, the main engine speed is 400~500rpm. The main engine speed should not be too high, otherwise it will cause carbonization of the product and produce small particles. At the same time, the main engine speed should not be too low, otherwise the plastic cannot be fully plasticized and melted in the screw, and large particles will be produced, which are unplasticized plastic particles, thereby affecting the finished product.

[0089] The melt temperature is controlled between 310 and 325°C; the extrusion temperature from zone 1 to zone 2 is between 200 and 260°C, from zone 3 to zone 6 is between 250 and 260°C, from zone 7 to zone 10 is between 230 and 250°C, and from zone 11 to the die head is between 240 and 260°C. By controlling the overall temperature, high melt temperatures prevent the polycarbonate and other additives from decomposing and affecting the preparation of polycarbonate composites.

[0090] In this preparation process, twin-screw extrusion and a special screw combination process are used to make antistatic polycarbonate composite materials. The melt temperature is controlled by the process at the extrusion granulation end, and only extrusion is required at the back end. It has the advantages of simple operation and mass production.

[0091] In some embodiments, the preparation method further comprises: pulling out the melt obtained after the melt mixing process through a shaping die at a constant moving speed, cooling it in a water tank, and pelletizing it after air drying to obtain a polycarbonate composite material.

[0092] In some embodiments, the obtained polycarbonate composite material has a particle diameter of 2-3 mm.

[0093] In a third aspect, a polycarbonate antistatic sheet is provided, including a polycarbonate composite material or a polycarbonate composite material prepared by a method for preparing a polycarbonate composite material.

[0094] The polycarbonate antistatic sheet provided in the third aspect of the embodiment of the present application includes the polycarbonate composite material provided in the first aspect above or the polycarbonate composite material prepared by the polycarbonate composite material preparation method provided in the second aspect above. Therefore, the obtained polycarbonate antistatic sheet has excellent antistatic properties, low crystal point, uniform conductivity, and high purity, which is conducive to its wide application in the field of electronic packaging.

[0095] In some embodiments, the method for preparing a polycarbonate antistatic sheet comprises the following steps:

[0096] G01 The prepared smooth polycarbonate composite particles and pure polycarbonate were placed in the casting machine baking process;

[0097] G02 The baked polycarbonate composite particles and pure polycarbonate, placed in their respective positions, using an automatic feeder to feed the material into the casting machine through the film composite extrusion into a sheet;

[0098] G03. The preformed sheet is rolled on a three-roll calender. The extruded sheet is cooled at an appropriate temperature and its thickness and flatness are adjusted to ensure it does not stick to the rollers, is glossy, has no flow marks, and has a low crystal point.

[0099] G04. The sheet material produced by roller pressing is polycarbonate antistatic sheet.

[0100] In step G01, the baking temperature is 110-120°C for 2-4 hours. If the baking temperature is lower than 110°C, the moisture cannot be dried out, resulting in water splashes and bubbles on the sheet. If the baking temperature is too high, the small molecules in the material will be decomposed during baking, resulting in bubbles and particles on the sheet. The baking time can be further adjusted according to the baking temperature during the specific processing process.

[0101] In a fourth aspect, a polycarbonate antistatic carrier tape is provided, which is prepared from a polycarbonate antistatic sheet.

[0102] The polycarbonate antistatic carrier provided in the fourth aspect of the embodiment of the present application is prepared by processing the above-mentioned polycarbonate antistatic sheet. The obtained polycarbonate antistatic carrier has a low surface crystal point, uniform conductivity, high cleanliness and high mechanical properties, good recyclability, and reuse does not affect the conductive properties. It has great application in electronic packaging materials.

[0103] In some embodiments, a method for preparing a polycarbonate antistatic carrier tape comprises the following steps:

[0104] J01. The smooth polycarbonate composite particles and pure polycarbonate were placed in a drying system of a casting machine and baked at 100-120°C for 2-4h.

[0105] J02. The baked polycarbonate composite pellets and pure polycarbonate are placed in their respective positions and fed by an automatic feeder. The pelletizer extrudes the carrier tape, punches the holes, slits the pellets, and winds the finished product.

[0106] Alternatively, the uncooled sheet can be made into a carrier tape by vacuum forming, and finally punched, slit and rolled into a finished product.

[0107] The following describes the details in conjunction with specific embodiments. Example 1

[0108] Polycarbonate composite material and preparation method thereof, polycarbonate antistatic material

[0109] ① Polycarbonate composite material, the raw material components include: polycarbonate 93.7wt%; carbon nanotubes 1wt%; compound dispersant 2wt%; antioxidant 0.5wt%; lubricant 1.8wt%; toughening agent 1wt%; wherein the carbon nanotubes are acidic carbon nanotubes, the diameter of the carbon nanotubes is 10 nm, the length is 10 μm, the aspect ratio is 1000:1, and the specific surface area is 200 m 2 / g, maximum particle size (Dmax) ≤50μm; the compound dispersant is selected from a mixture of an organic lubricant containing terminal hydroxyl groups and an inorganic dispersant, the mass ratio of the organic lubricant containing terminal hydroxyl groups to the inorganic dispersant is 1:1, the organic lubricant containing terminal hydroxyl groups is Wuhan hyperbranched HBP, and the inorganic dispersant is talc; the antioxidant is bis(2,4-dicumylphenyl) pentaerythritol diphosphite; the lubricant is a mixture of pentaerythritol stearate PETS and EBH, the mass ratio of the two is 1:1; the toughening agent is a terpolymer of methyl methacrylate-butadiene-styrene.

[0110] ② A method for preparing a polycarbonate composite material, comprising the following steps: pouring an inorganic dispersant into a high-speed stirrer and stirring at a high speed of 300 r / min for 15 minutes to obtain a first premix; breaking up the solid filler for better dispersion; mixing a lubricant, an antioxidant, an organic lubricant containing a terminal hydroxyl group, a toughening agent, and the first premix, and stirring and mixing them at a speed of 200 r / min for 5 minutes to uniformly disperse the additives to obtain an additive mixture; pouring the polycarbonate into a No. 1 loss-in-weight scale of a twin-screw extruder, then pouring the additive mixture into a No. 2 loss-in-weight scale, and finally pouring the carbon nanotubes into a No. 3 scale, according to the weight loss scale formula ratio of 93.7:5.3:1, Under double vacuum conditions, the materials are melt-mixed in a twin-screw extruder. The conditions for melt-mixing treatment using the twin-screw extruder include: using a medium-strength screw combination for treatment, a melt temperature of 310°C; a main engine speed of 460rpm; an extrusion temperature of 200-260°C from zone 1 to zone 2, an extrusion temperature of 250-260°C from zone 3 to zone 6, an extrusion temperature of 230-250°C from zone 7 to zone 10, and a temperature of 240-260°C from zone 11 to the die head; the melt obtained after the melt-mixing treatment is pulled out through a shaping die at a constant moving speed, then cooled in a water tank, air-dried and pelletized to obtain a polycarbonate composite material, wherein the particle diameter of the composite material is 2-3mm.

[0111] The surface resistivity of the prepared polycarbonate composite material color plate is 10 9 Ω / Sq, the resistance does not meet the standard.

[0112] ③ Polycarbonate antistatic materials include polycarbonate antistatic sheets or polycarbonate antistatic carrier tapes.

[0113] ④ A method for preparing a polycarbonate antistatic material, comprising: baking a smooth polycarbonate composite material and pure polycarbonate in a drying system of a casting machine at 120°C for 4 hours to remove moisture, forming the polycarbonate composite material as the upper and lower surface layers (two layers), and pure polycarbonate as the middle layer; placing the baked polycarbonate composite material and pure polycarbonate in their respective positions, feeding the materials using an automatic feeder, and feeding the materials into the casting machine through intramold co-extrusion to form a sheet. Alternatively, the sheet can be extruded into a carrier tape using a pelletizer, followed by punching, slitting, and winding. The initially formed sheet is rolled on a three-roll calender, cooled at an appropriate temperature, and the thickness and flatness of the sheet are adjusted to ensure that the sheet does not stick to the rollers, is glossy, and free of flow marks and crystal points. The sheet formed after rolling is the final sheet, which can be slit or sold directly to manufacturers. Alternatively, the sheet can be formed into a carrier tape using vacuum forming while still cool, and then punched, slit, and wound.

[0114] The prepared sheet / carrier has glossy and no flow marks and low crystal point, no pits on the back, no particles, but the surface resistivity is 10 10 Ω / Sq, is not within the required range. Example 2

[0115] Polycarbonate composite material and preparation method thereof, polycarbonate antistatic material and preparation method thereof

[0116] The polycarbonate composite material comprises the following raw materials: 92.2 wt% polycarbonate; 2.5 wt% carbon nanotubes; 2 wt% compound dispersant; 0.5 wt% antioxidant; 1.8 wt% lubricant; and 1 wt% toughening agent. The carbon nanotubes are acidic carbon nanotubes with a diameter of 20 nm, a length of 20 μm, an aspect ratio of 1000:1, and a specific surface area of ​​220 m 2 / g, maximum particle size (Dmax) ≤50μm; the compound dispersant is selected from a mixture of an organic lubricant containing terminal hydroxyl groups and an inorganic dispersant, the mass ratio of the organic lubricant containing terminal hydroxyl groups to the inorganic dispersant is 1:1, the organic lubricant containing terminal hydroxyl groups is Wuhan hyperbranched HBP, and the inorganic dispersant is talc; the antioxidant is bis(2,4-dicumylphenyl) pentaerythritol diphosphite; the lubricant is a mixture of pentaerythritol stearate PETS and EBH, the mass ratio of the two is 1:1; the toughening agent is a terpolymer of methyl methacrylate-butadiene-styrene.

[0117] The preparation method of the polycarbonate composite material and the preparation method of the polycarbonate antistatic material are consistent with the “Preparation method of the polycarbonate composite material and the preparation method of the polycarbonate antistatic material” provided in Example 1.

[0118] The prepared sheet / carrier is glossy, has no flow marks and low crystal point, has no pits on the back, and is basically free of particles. Example 3

[0119] Polycarbonate composite material and preparation method thereof, polycarbonate antistatic material and preparation method thereof

[0120] The polycarbonate composite material comprises the following raw materials: 90.7 wt% polycarbonate; 4 wt% carbon nanotubes; 2 wt% compound dispersant; 0.5 wt% antioxidant; 1.8 wt% lubricant; and 1 wt% toughening agent. The carbon nanotubes are acidic carbon nanotubes with a diameter of 30 nm, a length of 30 μm, an aspect ratio of 1000:1, and a specific surface area of ​​240 m 2 / g, maximum particle size (Dmax) ≤50μm; the compound dispersant is selected from a mixture of an organic lubricant containing terminal hydroxyl groups and an inorganic dispersant, the mass ratio of the organic lubricant containing terminal hydroxyl groups to the inorganic dispersant is 1:1, the organic lubricant containing terminal hydroxyl groups is Wuhan hyperbranched HBP, and the inorganic dispersant is talc; the antioxidant is bis(2,4-dicumylphenyl) pentaerythritol diphosphite; the lubricant is a mixture of pentaerythritol stearate PETS and EBH, the mass ratio of the two is 1:1; the toughening agent is a terpolymer of methyl methacrylate-butadiene-styrene.

[0121] The preparation method of the polycarbonate composite material is compared with the “preparation method of the polycarbonate composite material” provided in Example 1, wherein the “melt temperature of 310° C.” provided in Example 1 is modified to “melt temperature of 325° C.”, and the other steps are the same.

[0122] The preparation method of the polycarbonate antistatic material is consistent with the “Preparation method of the polycarbonate antistatic material” provided in Example 1.

[0123] The prepared sheet or carrier is glossy, has no flow marks and a few crystal points, has no pits on the back, and has a few particles less than 0.02 mm. Comparative Example 1

[0124] Polycarbonate composite material and preparation method thereof, polycarbonate antistatic material and preparation method thereof

[0125] The polycarbonate composite material comprises the following raw materials: 92.2 wt% polycarbonate; 2.5 wt% carbon nanotubes; 2 wt% compound dispersant; 0.5 wt% antioxidant; 1.8 wt% lubricant; and 1 wt% toughening agent. The carbon nanotubes are acidic carbon nanotubes with a diameter of 20 nm, a length of 20 μm, an aspect ratio of 1000:1, and a specific surface area of ​​220 m 2 / g, maximum particle size (Dmax) ≤50μm; the compound dispersant is selected from a mixture of an organic lubricant containing terminal hydroxyl groups and an inorganic dispersant, the mass ratio of the organic lubricant containing terminal hydroxyl groups to the inorganic dispersant is 1:1, the organic lubricant containing terminal hydroxyl groups is Wuhan hyperbranched HBP, and the inorganic dispersant is barium sulfate; the antioxidant is bis(2,4-dicumylphenyl) pentaerythritol diphosphite; the lubricant is a mixture of pentaerythritol stearate PETS and EBH, the mass ratio of the two is 1:1; the toughening agent is a terpolymer of methyl methacrylate-butadiene-styrene.

[0126] The preparation method of the polycarbonate composite material is compared with the “preparation method of the polycarbonate composite material” provided in Example 1, wherein the “melt temperature of 310° C.” provided in Example 1 is modified to “melt temperature of 322° C.”, and the other steps are the same.

[0127] The preparation method of the polycarbonate antistatic material is consistent with the “Preparation method of the polycarbonate antistatic material” provided in Example 1.

[0128] The prepared sheet or carrier has a bright appearance with some crystal points, and pitting formed by the magnified crystal points can be seen under a microscope. Comparative Example 2

[0129] Polycarbonate composite material and preparation method thereof, polycarbonate antistatic material and preparation method thereof

[0130] The polycarbonate composite material comprises the following raw materials: 92.2 wt% polycarbonate; 2.5 wt% carbon nanotubes; 2 wt% compound dispersant; 0.5 wt% antioxidant; 1.8 wt% lubricant; and 1 wt% toughening agent. The carbon nanotubes are acidic carbon nanotubes with a diameter of 20 nm, a length of 20 μm, an aspect ratio of 1000:1, and a specific surface area of ​​220 m 2 / g, maximum particle size (Dmax) ≤50μm; the compound dispersant is selected from a mixture of a common lubricant and an inorganic dispersant, the mass ratio of the common lubricant to the inorganic dispersant is 1:1, the common lubricant is pentaerythritol stearate, and the inorganic dispersant is talc; the antioxidant is bis(2,4-dicumylphenyl)pentaerythritol diphosphite; the lubricant is a mixture of pentaerythritol stearate PETS and EBH, the mass ratio of the two is 1:1; the toughening agent is a terpolymer of methyl methacrylate-butadiene-styrene.

[0131] The preparation method of the polycarbonate composite material is compared with the “preparation method of the polycarbonate composite material” provided in Example 1, in which the “melt temperature of 310° C.” provided in Example 1 is modified to “melt temperature of 339° C.”, and the other steps are the same.

[0132] The prepared polycarbonate composite material has poor effects in all aspects.

[0133] The preparation method of the polycarbonate antistatic material is consistent with the “Preparation method of the polycarbonate antistatic material” provided in Example 1.

[0134] The prepared sheet or carrier is dull, has flow marks, many crystal points, and many pits and particles on the back, wherein the particle size is 0.2-0.5 mm. Comparative Example 3

[0135] Polycarbonate composite material and preparation method thereof, polycarbonate antistatic material and preparation method thereof

[0136] The polycarbonate composite material comprises the following raw materials: 91.5 wt% polycarbonate; 3.2 wt% carbon nanotubes; 2 wt% compound dispersant; 0.5 wt% antioxidant; 1.8 wt% lubricant; and 1 wt% toughening agent. The carbon nanotubes are neutral carbon nanotubes with a diameter of 6 nm, a length of 6 μm, an aspect ratio of 1000:1, and a specific surface area of ​​220 m 2 / g, maximum particle size (Dmax) ≤50μm; the compound dispersant is selected from a mixture of an organic lubricant containing terminal hydroxyl groups and an inorganic dispersant, the mass ratio of the organic lubricant containing terminal hydroxyl groups to the inorganic dispersant is 1:1, the organic lubricant containing terminal hydroxyl groups is Wuhan hyperbranched HBP, and the inorganic dispersant is talc; the antioxidant is bis(2,4-dicumylphenyl) pentaerythritol diphosphite; the lubricant is a mixture of pentaerythritol stearate PETS and EBH, the mass ratio of the two is 1:1; the toughening agent is a terpolymer of methyl methacrylate-butadiene-styrene.

[0137] The preparation method of the polycarbonate composite material is compared with the “preparation method of the polycarbonate composite material” provided in Example 1, wherein the “melt temperature of 310° C.” provided in Example 1 is modified to “melt temperature of 322° C.”, and the other steps are the same.

[0138] The preparation method of the polycarbonate antistatic material is consistent with the “Preparation method of the polycarbonate antistatic material” provided in Example 1.

[0139] The prepared sheet or carrier tape has no flow marks, low crystal point and no pits. Comparative Example 4

[0140] Polycarbonate composite material and preparation method thereof, polycarbonate antistatic material and preparation method thereof

[0141] The polycarbonate composite material comprises the following raw materials: 91.5 wt% polycarbonate; 3.2 wt% carbon nanotubes; 2 wt% compound dispersant; 0.5 wt% antioxidant; 1.8 wt% lubricant; and 1 wt% toughening agent. The carbon nanotubes are weakly alkaline carbon nanotubes with a diameter of 6 nm, a length of 6 μm, an aspect ratio of 1000:1, and a specific surface area of ​​220 m 2 / g, maximum particle size (Dmax) ≤50μm; the compound dispersant is selected from a mixture of an organic lubricant containing terminal hydroxyl groups and an inorganic dispersant, the mass ratio of the organic lubricant containing terminal hydroxyl groups to the inorganic dispersant is 1:1, the organic lubricant containing terminal hydroxyl groups is Wuhan hyperbranched HBP, and the inorganic dispersant is talc; the antioxidant is bis(2,4-dicumylphenyl) pentaerythritol diphosphite; the lubricant is a mixture of pentaerythritol stearate PETS and EBH, the mass ratio of the two is 1:1; the toughening agent is a terpolymer of methyl methacrylate-butadiene-styrene.

[0142] The preparation method of the polycarbonate composite material was compared to the "Preparation Method of the Polycarbonate Composite Material" provided in Example 1, except that the "melt temperature of 310°C" in Example 1 was modified to "melt temperature of 330°C." The other steps were identical. The resulting polycarbonate composite material was a rough polycarbonate composite material.

[0143] The preparation method of the polycarbonate antistatic material is consistent with the “Preparation method of the polycarbonate antistatic material” provided in Example 1.

[0144] The prepared sheet or carrier is dull, has flow marks, many crystal points, and many pits and particles on the back, with a particle size of 0.15-0.5 mm. Comparative Example 5

[0145] Polycarbonate composite material and preparation method thereof, polycarbonate antistatic material and preparation method thereof

[0146] The polycarbonate composite material comprises the following raw materials: 92.2 wt% polycarbonate; 2.5 wt% carbon nanotubes; 2 wt% compound dispersant; 0.5 wt% antioxidant; 1.8 wt% lubricant; and 1 wt% toughening agent. The carbon nanotubes are acidic carbon nanotubes with a diameter of 6 nm, a length of 6 μm, an aspect ratio of 1000:1, and a specific surface area of ​​220 m 2 / g, maximum particle size (Dmax) ≤50μm; the compound dispersant is selected from a mixture of an organic lubricant containing terminal hydroxyl groups and an inorganic dispersant, the mass ratio of the organic lubricant containing terminal hydroxyl groups to the inorganic dispersant is 1:1, the organic lubricant containing terminal hydroxyl groups is Wuhan hyperbranched HBP, and the inorganic dispersant is talc; the antioxidant is bis(2,4-dicumylphenyl) pentaerythritol diphosphite; the lubricant is a mixture of pentaerythritol stearate PETS and EBH, the mass ratio of the two is 1:1; the toughening agent is a terpolymer of methyl methacrylate-butadiene-styrene.

[0147] The preparation method of the polycarbonate composite material is compared with the “preparation method of the polycarbonate composite material” provided in Example 1, in which the “melt temperature is 310°C” provided in Example 1 is modified to “melt temperature is 326°C”, and the “double vacuuming” provided in Example 1 is modified to “single vacuuming”, and the other steps are the same.

[0148] The overall effect of the prepared polycarbonate composite material is average.

[0149] The preparation method of the polycarbonate antistatic material is consistent with the “Preparation method of the polycarbonate antistatic material” provided in Example 1.

[0150] The prepared sheet or carrier has gloss, no flow marks, low crystal point and many small particles and a few pits, and the particle size is 0.15-0.20 mm. Performance testing and result analysis

[0151] The density, tensile strength, flexural strength, flexural modulus, impact strength, melt temperature, surface resistivity of the polycarbonate composite materials obtained in Examples 1 to 3 and Comparative Examples 1 to 5, as well as the surface resistivity and surface morphology of the polycarbonate antistatic material (sheet) were tested. The results are shown in Table 1 below. It can be found that: Example 1, Example 2, and Example 3 are comparisons of different acidic carbon nanotube contents. As can be seen from Table 1, as the content of the conductive agent acidic CNT increases, the conductivity gradually increases, and the tensile strength, flexural strength, and flexural modulus also increase accordingly, but the impact strength decreases accordingly; from the appearance of the sheet: as the content of the conductive agent acidic CNT increases, the CNT content in the entire system increases, causing the CNTs to agglomerate and form crystal points; crystal points begin to appear on the surface of the sheet, and these crystal points can only be seen under a microscope. The difference between Example 2 and Comparative Example 1 lies in the inorganic filler dispersant. Comparative Example 1 uses high-mesh barium sulfate. The barium sulfate has a granular structure, resulting in a shiny sheet with some crystal points. These crystal points are aggregates of barium sulfate and CNTs. The maximum particle size of the barium sulfate is greater than 0.015 mm, making it easy to form white crystal points on the sheet surface. The difference between Example 2 and Comparative Example 2 lies in the lubricant. Comparative Example 2 uses a common high-temperature lubricant. Although both are high-temperature lubricants, the compounded high-temperature lubricant in Example 2 uses terminal hydroxyl groups, which have special functionality and interact synergistically with the acidic carbon nanotubes. This reduces the melt temperature during production, reducing the decomposition of other additives and low-viscosity polycarbonate. The special lubricant system combined with the dispersant allows the acidic carbon nanotubes to be evenly dispersed in the polycarbonate matrix. This results in a sheet with low surface resistivity, a smooth surface, and low crystal points, suitable for use as a semiconductor sheet. The difference between Example 2 and Comparative Example 3 lies in the carbon nanotubes. The neutral carbon nanotubes used in Comparative Example 3, compared to the acidic carbon nanotubes obtained by acid treatment in Example 2, remove surface impurities and oxides, resulting in highly pure, oxidized acidic carbon nanotubes. While achieving the same resistance and surface energy, the addition amount of neutral multi-walled carbon nanotubes is higher than that of acidic carbon nanotubes. The increased carbon nanotube content leads to an increase in melt temperature and a decrease in impact strength. The difference between Example 2 and Comparative Example 4 lies in the different acidity and alkalinity of the carbon nanotubes, which depends on the acidity and alkalinity of the catalyst. As shown in Table 1, polycarbonate is weakly acidic. If weakly alkaline carbon nanotubes are used, an acid-base neutralization reaction will occur, generating gas and causing pits in the extruded sheet. The difference between Example 2 and Comparative Example 5 is that Comparative Example 5 uses a single vacuum pump, which is less powerful than a double vacuum pump, resulting in some small molecules not being removed, resulting in a small number of hollow particles in the extruded sheet.

[0152] Table 1 Test items Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Density g / cm 31.2121.2151.2191.2161.2151.2161.2161.215Tensile strengthMPa5558605856595558Flexural strengthMPa95991029795969598Flexural modulusMPa25002700285026502600280026002780Impact strengthkJ / m 2 19.017.012.014149.59.013 Melt temperature / °C 310319325322339322330326 (color plate) Surface resistivity Ω / Sq10 9 10 4 10 3 10 5 10 6 10 4 10 6 10 5 Sheet surface resistivity Ω / Sq (front and back) 10 10 -10 13 10 5 -10 8 10 4 -10 7 10 5 -10 8 10 6 -10 9 10 4 -10 8 10 6 -10 10 10 5 -10 10 The surface of the sheet has no crystal points, low crystal points, a few crystal points, and a bright surface. Some crystal points have many particles and pits. Low crystal points have many particles and pits. There are a few small hollow particles and a small number of pits.

[0153] In summary, the polycarbonate composite material provided in the present application uses polycarbonate as the main component, and is used in conjunction with carbon nanotubes, compound dispersants, antioxidants, lubricants and toughening agents. Carbon nanotubes are used as conductive agents instead of traditional conductive carbon black and other conductive materials to ensure that mold ash will not be generated in the process of manufacturing sheets or carriers, and the material cleanliness is high. The use of a compound dispersant system containing a mixture of an organic lubricant and an inorganic dispersant containing terminal hydroxyl groups can help improve the dispersion effect of carbon nanotubes in polycarbonate materials, reduce surface resistivity, ensure that the material has uniform conductivity, and avoid uneven conductivity caused by the uneven surface of the obtained sheet or carrier; in addition, the toughening agent can improve the overall mechanical properties of the polycarbonate composite material, and the antioxidant and lubricant can ensure that the material properties are stable and easy to process; therefore, the present application uses polycarbonate as the main component, and modifies polycarbonate by using carbon nanotubes and a compound dispersant system to obtain a polycarbonate composite material with low crystal point, uniform conductivity and high cleanliness, which is conducive to wide application.

[0154] The above are merely optional embodiments of the present application and are not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present application should be included within the scope of the claims of the present application.

Claims

1. A polycarbonate composite material, characterized in that: Taking the total weight of the polycarbonate composite material as 100%, the polycarbonate composite material includes the following components in weight percentage: 70-97.2wt% of polycarbonate; 1-10wt% of carbon nanotubes; 0.2-3wt% of compound dispersant; 0.1-0.5wt% of antioxidant; 0.5-2wt% of lubricant; and 1-2wt% of toughening agent. The compound dispersant is selected from a mixture of an organic lubricant containing terminal hydroxyl groups and an inorganic dispersant.

2. The polycarbonate composite material according to claim 1, characterized in that: In the compound dispersant, the mass ratio of the organic lubricant containing terminal hydroxyl groups to the inorganic dispersant is 1:1-1.2; and / or, the organic lubricant containing terminal hydroxyl groups includes Wuhan hyperbranched HBP-160; and / or, the inorganic dispersant includes at least one of calcium carbonate, barium sulfate, talc, boron nitride, silicon dioxide, alum, titanium dioxide, calcium oxide, magnesium oxide, carbon black, and mica powder.

3. The polycarbonate composite material according to claim 1, characterized in that: The particle size of the inorganic dispersant is 5000-10000 mesh.

4. The polycarbonate composite material according to claim 1, characterized in that: The carbon nanotubes include acidified carbon nanotubes.

5. The polycarbonate composite material according to claim 1, characterized in that: The diameter of the carbon nanotube is 2-20 nm; and / or, the length of the carbon nanotube is 2-50 μm; and / or, the aspect ratio of the carbon nanotube is 1000-5000:1; and / or, the specific surface area of ​​the carbon nanotube is 200-280 m 2 / g.

6. The polycarbonate composite material according to claim 1, characterized in that: The polycarbonate is selected from a combination of a low-viscosity polycarbonate having a melt index of 20 to 30 g / 10 min and a high-viscosity polycarbonate having a melt index of 5 to 8 g / 10 min.

7. The polycarbonate composite material according to claim 6, characterized in that: In the polycarbonate, the mass ratio of the low-viscosity polycarbonate to the high-viscosity polycarbonate is 2-3:

7.

8. The polycarbonate composite material according to claim 1, characterized in that: The antioxidant includes a phosphate antioxidant; and / or the lubricant includes at least one of pentaerythritol stearate and N,N'-ethylenebis-12-hydroxystearamide; and / or the toughening agent includes at least one of a terpolymer of methyl methacrylate-butadiene-styrene, a polyolefin elastomer, and an ethylene-methyl acrylate copolymer.

9. The polycarbonate composite material according to claim 8, characterized in that: The phosphate antioxidant includes bis(2,4-dicumylphenyl)pentaerythritol diphosphite.

10. A method for preparing a polycarbonate composite material, characterized in that: The steps include: Providing raw materials of various components according to the polycarbonate composite material according to any one of claims 1 to 9; The compound dispersant, the antioxidant, the lubricant and the toughening agent are dispersed separately and then mixed to obtain an auxiliary agent mixture; The polycarbonate, the carbon nanotubes and the auxiliary agent mixture are melt-mixed to obtain a polycarbonate composite material.

11. The method for preparing the polycarbonate composite material according to claim 10, characterized in that: The melt mixing process comprises: performing melt mixing process by using a twin-screw extruder under double vacuum conditions.

12. The method for preparing the polycarbonate composite material according to claim 10, characterized in that: The conditions for melt mixing treatment using a twin-screw extruder include: a melt temperature of 310-325°C; a main engine speed of 400-500rpm; an extrusion temperature from zone 1 to zone 2 of 200-260°C, an extrusion temperature from zone 3 to zone 6 of 250-260°C, an extrusion temperature from zone 7 to zone 10 of 230-250°C, and a temperature from zone 11 to the die head of 240-260°C.

13. The method for preparing the polycarbonate composite material according to claim 10, characterized in that: The preparation method further comprises: pulling out the molten body obtained after the melt mixing process through a shaping die at a constant moving speed, cooling it in a water tank, and pelletizing it through air drying to obtain a polycarbonate composite material.

14. A polycarbonate antistatic sheet, characterized in that: The invention comprises the polycarbonate composite material according to any one of claims 1 to 9 or the polycarbonate composite material prepared by the method for preparing the polycarbonate composite material according to any one of claims 10 to 13.

15. A polycarbonate antistatic carrier tape, characterized in that: Prepared from the polycarbonate antistatic sheet according to claim 14.