ABS sheet and preparation method therefor, and modified carbon nanotube and preparation method therefor

Abstract

The present application belongs to the technical field of electronic packaging materials, and in particular relates to an ABS sheet and a preparation method therefor, and a modified carbon nanotube and a preparation method therefor. The ABS sheet comprises an ABS composite middle layer and a surface layer provided on at least one surface of the ABS composite middle layer, wherein the surface layer comprises the following components in parts by weight: 80-100 parts of polystyrene, 5-15 parts of modified carbon nanotubes, 2-10 parts of a toughening agent, 1-5 parts of an inorganic filler, 0-1 part of a first lubricant and 0-1 part of a first antioxidant; and the modified carbon nanotube comprises carbon nanotubes and polybutadiene connected with the carbon nanotubes by means of a chemical bond. The present application can achieve significant improvements in the overall antistatic performance and surface smoothness performance of the ABS sheet, and can be better applied to the electronic packaging field.

Description

ABS sheet and preparation method thereof, modified carbon nanotube and preparation method thereof Technical Field

[0001] The present application relates to the technical field of electronic packaging materials, and in particular to an ABS sheet and a preparation method thereof, and a modified carbon nanotube and a preparation method thereof. Background Art

[0002] Plastic leather is a semi-finished sheet material used in electronic packaging. This semi-finished sheet is manufactured into carrier tape through a blister or slicing process. The plastic leather or carrier tape contains a layer of polymer material and may contain fillers such as conductive carbon black, graphite, or carbon fiber.

[0003] ABS (Acrylonitrile Butadiene Styrene) plastic is a terpolymer of acrylonitrile (A), butadiene (B), and styrene (S). It is widely used in the mechanical, electrical, textile, automotive, aircraft, and shipbuilding industries, as well as in the chemical industry. ABS has excellent mechanical properties and impact strength, making it suitable for use as an intermediate layer material in carrier tapes. However, its antistatic properties are relatively low.

[0004] Polystyrene (PS) is a commonly used raw material for antistatic coatings, and carbon black is widely used as a conductive additive in these coatings. However, carbon black requires a relatively high dosage to achieve conductivity and is prone to dusting, which can affect the cleanliness of the finished product. High-surface-area carbon nanotubes (CNTs), on the other hand, offer excellent mechanical, electrical, and thermal stability properties, significantly improving material performance with just a small addition. However, CNTs are prone to agglomeration due to van der Waals forces, which limits the antistatic performance of ABS sheets. Technical issues

[0005] The purpose of the embodiments of the present application is to provide an ABS sheet and a preparation method thereof, and a modified carbon nanotube and a preparation method thereof. Technical Solutions

[0006] The technical solution adopted in the embodiment of this application is:

[0007] In a first aspect, an ABS sheet is provided, comprising an ABS composite material intermediate layer and a surface layer disposed on at least one surface of the ABS composite material intermediate layer; wherein the surface layer comprises the following components in parts by weight:

[0008] 80-100 parts of polystyrene; 5-15 parts of modified carbon nanotubes; 2-10 parts of toughening agent; 1-5 parts of inorganic filler; 0-1 part of first lubricant; 0-1 part of first antioxidant; the modified carbon nanotubes include carbon nanotubes and polybutadiene connected to the carbon nanotubes through chemical bonds.

[0009] In some embodiments, the modified carbon nanotube structure comprises:

[0010] CNT-NH-CO-NH-R-NH-CO-NH-(CH2CH=CHCH2) n -NH-CO-NH-R-NH-CO-NH-CNT; wherein CNT refers to carbon nanotube, and R includes at least one of a phenyl group and an alkyl group.

[0011] In some embodiments, the polystyrene comprises high impact polystyrene; and / or,

[0012] The toughening agent includes at least one of butadiene rubber, isoprene rubber, styrene-butadiene-styrene rubber, styrene-isoprene-styrene rubber, acrylonitrile-butadiene rubber, styrene-butadiene rubber, ethylene-propylene rubber, and styrene-ethylene-butadiene-styrene rubber; and / or,

[0013] The inorganic filler includes at least one of calcium carbonate, barium sulfate, boron nitride, silicon dioxide, alum, titanium dioxide, calcium oxide, magnesium oxide, carbon black, talc powder and mica powder; and / or,

[0014] The first lubricant includes at least one of calcium stearate, talc and polyethylene wax; and / or,

[0015] The first antioxidant includes at least one of antioxidant 1010 , antioxidant 168 , antioxidant 1076 , antioxidant 1330 , antioxidant 1035 , antioxidant 3144 , antioxidant 1024 , and antioxidant 126 .

[0016] In some embodiments, the ABS composite material middle layer includes the following components in parts by weight: 30-40 parts of a first ABS resin; 30-40 parts of a second ABS resin; 5-15 parts of nano-calcium carbonate; 0-0.05 parts of a second antioxidant; 0-3 parts of a second lubricant; and 0-5 parts of a compatibilizer.

[0017] In some embodiments, the first ABS resin has a weight average molecular weight of 150,000 to 200,000 g / mol and a melt flow rate of 8 to 18 g / 10 min; and / or

[0018] The second ABS resin has a weight average molecular weight of 150,000 to 200,000 g / mol and a melt flow rate of 4 to 8 g / 10 min; and / or

[0019] Nano calcium carbonate includes calcium carbonate surface-treated with stearic acid additives; and / or,

[0020] The second lubricant comprises at least one of calcium stearate, talc and polytetrafluoroethylene; and / or,

[0021] The second antioxidant includes at least one of antioxidant 1010, antioxidant 168, antioxidant 1076, antioxidant 1330, antioxidant 1035, antioxidant 3144, antioxidant 1024, and antioxidant 126; and / or,

[0022] The compatibilizer includes at least one of a terpolymer of methyl methacrylate-butadiene-styrene, a polyolefin elastomer, and an ethylene-methyl acrylate copolymer.

[0023] In some embodiments, the thickness of the ABS sheet is 0.2 to 1.0 mm; and / or,

[0024] The thickness of the middle layer of the ABS composite material accounts for greater than or equal to 80% of the total thickness of the ABS sheet.

[0025] In a second aspect, a method for preparing an ABS sheet is provided, comprising:

[0026] Providing the raw materials for the intermediate layer and the surface layer of the ABS composite material in the ABS sheet of the first aspect;

[0027] The raw materials of the middle layer and the surface layer of the ABS composite material are extruded and compression molded to obtain an ABS sheet.

[0028] In some embodiments, the extrusion compression molding conditions include: the extrusion temperature of the raw material of the middle layer of the ABS composite material is 200-240°C, and the extrusion temperature of the raw material of the surface layer is 180-230°C.

[0029] In some embodiments, the preparation method of the raw material of the surface layer includes:

[0030] Polystyrene, modified carbon nanotubes, a toughening agent, an inorganic filler, a first lubricant and a first antioxidant are mixed and melt-extruded and granulated to obtain raw materials for the surface layer.

[0031] In some embodiments, the method for preparing the raw materials of the ABS composite material middle layer includes:

[0032] The first ABS resin, the second ABS resin, nano calcium carbonate, the second antioxidant, the second lubricant and the compatibilizer are mixed and melt-extruded to form granules to obtain the raw material of the middle layer of the ABS composite material.

[0033] In a third aspect, a modified carbon nanotube is provided, comprising a carbon nanotube and polybutadiene connected to the carbon nanotube via a chemical bond.

[0034] In some embodiments, the modified carbon nanotube structure comprises:

[0035] CNT-NH-CO-NH-R-NH-CO-NH-(CH2CH=CHCH2) n -NH-CO-NH-R-NH-CO-NH-CNT; wherein CNT refers to carbon nanotube, and R includes at least one of a phenyl group and an alkyl group.

[0036] In some embodiments, the carbon nanotubes have an inner diameter of 1 to 4 nm, an outer diameter of 8 to 25 nm, a length of 1 to 100 μm, an aspect ratio of 5000 to 10000:1, and a specific surface area of ​​200 to 300 m 2 / g.

[0037] In a fourth aspect, a method for preparing modified carbon nanotubes is provided, comprising:

[0038] The carbon nanotubes with amino groups on the surface are mixed with an organic substance containing a diisocyanate group to carry out a first chemical reaction to obtain an intermediate product;

[0039] The intermediate product is mixed with amino-terminated polybutadiene to carry out a second chemical reaction to obtain modified carbon nanotubes.

[0040] In some embodiments, the organic compound containing a diisocyanate group includes at least one of diphenylmethane diisocyanate, diphenylpropane diisocyanate, diphenylbutane diisocyanate, toluene diisocyanate, and dimethyldiphenyl diisocyanate; and / or

[0041] The temperature of the first chemical reaction is 80-120°C; and / or,

[0042] The temperature of the second chemical reaction is 80~120℃. Beneficial effects

[0043] The ABS sheet provided in the embodiments of the present application has the following beneficial effects: by modifying the surface layer components of the ABS sheet to include a certain weight percentage of polystyrene, modified carbon nanotubes, a toughening agent, an inorganic filler, a first lubricant, and a first antioxidant; wherein the modified carbon nanotubes are carbon nanotubes grafted with polybutadiene, and the dispersibility of such modified carbon nanotubes in polystyrene is significantly improved, while the toughening agent can also improve the overall mechanical properties of the surface layer containing the polystyrene main material. Therefore, the ABS sheet of the present application forms a surface layer with a uniform dispersion of carbon nanotubes through the combined action of the various components in the surface layer formulation, which significantly improves the overall antistatic properties and surface smoothness of the ABS sheet, making it more suitable for application in the field of electronic packaging.

[0044] The beneficial effect of the ABS sheet preparation method provided in the embodiments of this application lies in that, by extruding and compression molding the raw materials for the intermediate layer and the surface layer of the ABS composite material, an ABS sheet with uniformly dispersed carbon nanotubes on the surface layer is obtained. This preparation method is not only easy to process, but also, due to the interaction of the various components in the surface layer raw materials, the resulting ABS sheet has excellent antistatic properties and surface smoothness, making it suitable for use in the preparation of electronic packaging materials.

[0045] The beneficial effect of the modified carbon nanotubes provided in the embodiments of the present application is that: by chemically grafting polybutadiene onto carbon nanotubes to form modified carbon nanotubes, the dispersibility of the carbon nanotubes can be improved. Such modified carbon nanotubes can be used as fillers in the surface layer of ABS sheets and can be evenly dispersed, thereby obtaining an antistatic ABS sheet with good surface conductivity uniformity.

[0046] The beneficial effect of the preparation method of modified carbon nanotubes provided in the embodiments of the present application is that: after reacting carbon nanotubes with surface amino groups with an organic substance containing diisocyanate groups, the carbon nanotubes are mixed with amine-terminated polybutadiene for reaction. The amine-terminated polybutadiene has terminal amine groups that are more active than hydroxyl groups and reacts faster with isocyanate-active groups. This allows the carbon nanotubes and polybutadiene to be connected through groups containing -NH-CO-NH- to obtain modified carbon nanotubes grafted with polybutadiene. Such a preparation method is simple, and the obtained modified carbon nanotubes can be used as a filler in the surface layer of ABS sheet, which can significantly improve the surface conductivity uniformity and antistatic properties of the ABS sheet. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the embodiments or exemplary technical descriptions. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0048] FIG1 is a schematic flow chart of a method for preparing an ABS sheet according to an embodiment of the present application;

[0049] FIG2 is a schematic flow chart of a method for preparing modified carbon nanotubes provided in one embodiment of the present application. Modes for Carrying Out the Invention

[0050] In order to make the purpose, technical solutions and advantages of this application more clear, the following further describes this application in detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0051] In this application, the term "and / or" describes the relationship between associated objects, indicating that three possible relationships exist. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. A and B can be singular or plural. The character " / " generally indicates that the associated objects are in an "or" relationship.

[0052] In this application, "at least one" means one or more, "more than one" means two or more. "At least one of the following" or similar expressions refers to any combination of these items, including any combination of single or plural items.

[0053] It should be understood that in the various embodiments of the present application, the serial numbers of the above-mentioned processes do not mean the order of execution. Some or all of the steps can be executed in parallel or sequentially. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0054] The terms used in the embodiments of the present application are only for the purpose of describing specific embodiments and are not intended to limit the present application. The singular forms "a", "an", "the" and "the" used in the embodiments of the present application and the appended claims are also intended to include plural forms unless the context clearly indicates otherwise.

[0055] The terms "first" and "second" are used solely for descriptive purposes to distinguish objects, such as substances, from one another and should not be understood to indicate or imply relative importance or to implicitly specify the quantity of the technical features being referred to. For example, without departing from the scope of the embodiments of this application, a first XX may also be referred to as a second XX, and similarly, a second XX may also be referred to as a first XX. Thus, features defined as "first" or "second" may explicitly or implicitly include one or more of such features.

[0056] Plastic leather is a semi-finished sheet material used in electronic packaging. This semi-finished sheet is manufactured into carrier tape through a blister or slicing process. Carrier tape is a packaging product used in electronic packaging. It is used in conjunction with cover tape to hold electronic components such as resistors, capacitors, transistors, and diodes within the carrier tape's cavities (also known as pockets). The cover tape is then sealed over the carrier tape to form a closed package, protecting the electronic components from contamination and damage during transportation. Plastic leather or carrier tape typically contains a non-conductive polymer material as a middle layer, while the upper and lower surface layers are conductive material. Polystyrene is commonly used as the base material for these conductive layers in the market.

[0057] ABS resin is a terpolymer of acrylonitrile (A), butadiene (B), and styrene (S). It combines the properties of all three components: acrylonitrile imparts chemical and heat resistance, along with a certain surface hardness; butadiene imparts high elasticity and toughness; and styrene enhances processing and molding capabilities, improving electrical properties. Therefore, ABS resin is a tough, hard, and rigid material with readily available raw materials, excellent overall performance, low price, and a wide range of applications. ABS resin is widely used in the manufacturing industries, including machinery, electrical equipment, textiles, automobiles, aircraft, and ships, as well as in the chemical industry. ABS possesses excellent mechanical properties and impact strength, can be used at low temperatures, and offers excellent wear resistance, good dimensional stability, and oil resistance. ABS can be used as the interlayer material for carrier tapes, and the performance advantages of various fillers can be utilized to enhance its overall performance.

[0058] Polystyrene is a commonly used raw material for antistatic surfaces, and carbon black is widely used in antistatic surfaces as a conductive additive. However, carbon black requires a large amount to achieve conductive properties and is prone to dusting, affecting the cleanliness of the product. Compared with traditional carbon black, carbon nanotubes with a high specific surface area can significantly improve the material's performance, such as mechanical properties, conductivity, and thermal stability, with only a small amount of addition. However, due to the high aspect ratio of carbon nanotubes, they are very easy to entangle and form agglomerates. During the composite process with other materials, they are very likely to agglomerate into small particles, affecting the performance of the product. Therefore, the dispersibility of carbon nanotubes in composite materials has always been a bottleneck affecting the application of carbon nanotubes. This means that even if carbon nanotubes are used in ABS sheets, their antistatic performance is limited.

[0059] To improve the dispersion of carbon nanotubes in the surface layer of ABS sheets, thereby obtaining antistatic ABS sheets with a uniform and smooth surface and good conductivity, this application investigates the dispersion properties of carbon nanotubes themselves and simultaneously improves their dispersion in polystyrene resin by grafting and modifying them, achieving unexpected results. In light of this, the present application provides the following technical solutions.

[0060] ABS sheet

[0061] In a first aspect, an embodiment of the present application provides an ABS sheet, comprising an ABS composite material middle layer and a surface layer provided on at least one surface of the ABS composite material middle layer; wherein the surface layer comprises the following components in parts by weight: 80 to 100 parts of polystyrene; 5 to 15 parts of modified carbon nanotubes; 2 to 10 parts of a toughening agent; 1 to 5 parts of an inorganic filler; 0 to 1 part of a first lubricant; and 0 to 1 part of a first antioxidant; the modified carbon nanotubes include carbon nanotubes and polybutadiene connected to the carbon nanotubes by chemical bonds.

[0062] The present embodiment improves the surface layer components of the ABS sheet to include a certain weight ratio of polystyrene, modified carbon nanotubes, a toughening agent, an inorganic filler, a first lubricant, and a first antioxidant. The modified carbon nanotubes are carbon nanotubes grafted with polybutadiene, significantly improving their dispersibility in the polystyrene, while the toughening agent also enhances the overall mechanical properties of the surface layer containing the polystyrene matrix. Therefore, the ABS sheet of the present application, through the combined action of the various components in the surface layer formulation, forms a surface layer with a uniform dispersion of carbon nanotubes. This significantly improves the overall antistatic properties and surface smoothness of the ABS sheet, making it more suitable for electronic packaging applications.

[0063] Specifically, the ABS composite middle layer of the ABS sheet comprises ABS composite material and includes two opposing surfaces. The surface layer is provided on one or both surfaces of the ABS composite middle layer. To improve practicality, the surface layer is provided on both surfaces of the ABS composite middle layer. The surface layer contains modified carbon nanotubes with good dispersion.

[0064] In some embodiments, the modified carbon nanotube structure comprises:

[0065] CNT-NH-CO-NH-R-NH-CO-NH-(CH2CH=CHCH2) n -NH-CO-NH-R-NH-CO-NH-CNT; where CNT refers to carbon nanotubes and R includes at least one of phenyl and alkyl groups. This is polybutadiene (CH2CH=CHCH2) n The carbon nanotubes are connected by two urea groups (-NH-CO-NH-) at both ends via R, forming a uniformly dispersed network of carbon nanotubes. The modified carbon nanotubes may comprise 5 to 15 parts by weight in the surface layer, and may be, for example, 5, 6, 8, 10, 12, or 14 parts.

[0066] In some embodiments, the carbon nanotubes modified with polybutadiene have an inner diameter of 1-4 nm, an outer diameter of 8-25 nm, a length of 1-100 μm, and an aspect ratio of 5000-10000:1; specifically, the aspect ratio can be 5000:1, 6000:1, 8000:1, 9000:1, 5000:1, etc. The specific surface area (BET) of the carbon nanotubes is 200-300 m 2 / g, for example, can be 200m 2 / g,240m 2 / g,260m 2 / g,280m 2 / g,300m 2 / g, etc. Furthermore, the ash content of the carbon nanotubes is ≤2%. The above carbon nanotubes have better dispersibility and conductivity.

[0067] In some embodiments, the polystyrene in the surface layer comprises high-impact polystyrene (HIPS). The weight-average molecular weight of HIPS is 30,000 to 50,000 g / mol, for example, 30,000 g / mol, 35,000 g / mol, 38,000 g / mol, 40,000 g / mol, 45,000 g / mol, 48,000 g / mol, 50,000 g / mol, etc. HIPS has excellent dimensional stability, impact strength, and rigidity. Its melt index at 300°C and 1.2 kg can reach 15 to 25 g / 10 min. The weight of the polystyrene in the surface layer is 80 to 100 parts by weight, for example, 82, 84, 86, 90, 95, etc.

[0068] In some embodiments, the toughening agent in the surface layer includes at least one of butadiene rubber, isoprene rubber, styrene-butadiene-styrene rubber, styrene-isoprene-styrene rubber, acrylonitrile-butadiene rubber, styrene-butadiene rubber, ethylene-propylene rubber, and styrene-ethylene-butadiene-styrene rubber. These toughening agents can improve the overall toughening properties of polystyrene. The toughening agent in the surface layer is present in an amount of 2 to 10 parts by weight, for example, 2, 3, 4, 6, 8, or 9 parts.

[0069] In some embodiments, the inorganic filler in the surface layer includes at least one of calcium carbonate, barium sulfate, boron nitride, silicon dioxide, alum, titanium dioxide, calcium oxide, magnesium oxide, carbon black, talc, and mica powder. Furthermore, the inorganic filler can be compounded with barium sulfate and talc. Such an inorganic filler exhibits high dimensional stability while also improving the heat resistance and brightness of the ABS sheet. The amount of inorganic filler in the surface layer is 1 to 5 parts by weight, for example, 2, 3, 4, or 5 parts.

[0070] In some embodiments, a first lubricant may or may not be added to the surface layer as needed. Specifically, when a first lubricant is added, the first lubricant in the surface layer comprises at least one of calcium stearate, talc, and polyethylene wax. The first lubricant is selected to be heat-resistant and migration-resistant, preventing precipitation and migration on the ABS sheet surface at high temperatures. Furthermore, the particle size of the first lubricant can range from 500 mesh to 10,000 mesh. The weight of the first lubricant in the surface layer of the ABS sheet ranges from 0 to 1 part, for example, 0.1 part, 0.2 part, 0.4 part, 0.6 part, 0.8 part, 1 part, etc.

[0071] In some embodiments, the surface layer may be added with or without a first antioxidant as needed. Specifically, when the first antioxidant is added, the first antioxidant in the surface layer includes antioxidant 1010 [i.e., pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate]], antioxidant 168 [i.e., tris[2,4-di-tert-butylphenyl] phosphite], antioxidant 1076 [i.e., β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate], At least one of: octadecyl alcohol ester, antioxidant 1330 (1,3,5-trimethyl-2,4,6-(3,5-di-tert-butyl-4-hydroxybenzyl)benzene), antioxidant 1035 (2,2'-thiobis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]), antioxidant 3144 (1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)isocyanuric acid), antioxidant 1024 (N,N'-bis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl]hydrazine), and antioxidant 126 (bis(2,4-di-tert-butylphenyl)pentaerythritol diphosphite). These antioxidants can improve the oxidation resistance of the ABS sheet surface, thereby extending its service life. The weight portion of the first antioxidant in the surface layer of the ABS sheet is 0-1 part, such as 0.1 part, 0.2 part, 0.4 part, 0.6 part, 0.8 part, 1 part, etc.

[0072] It should be noted that the weight parts of the above-mentioned polystyrene, modified carbon nanotubes, toughening agent, inorganic filler, first lubricant and first antioxidant refer to the weight parts in the surface layer of one or both sides of the ABS sheet.

[0073] In some embodiments, the ABS composite middle layer of the ABS sheet includes the following components by weight: 30-40 parts of a first ABS resin; 30-40 parts of a second ABS resin; 5-15 parts of nano-calcium carbonate; 0-0.05 parts of a second antioxidant; 0-3 parts of a second lubricant; and 0-5 parts of a compatibilizer. By optimizing the formulation of the ABS composite middle layer, the overall performance of the ABS sheet as a carrier tape for semiconductor packaging is improved.

[0074] In some embodiments, the weight average molecular weight of the first ABS resin is 150,000 to 200,000 g / mol, for example, 150,000 g / mol, 160,000 g / mol, 180,000 g / mol, 190,000 g / mol, 200,000 g / mol, etc., and the melt flow rate is 8 to 18 g / 10 min, for example, 8 g / 10 min, 10 g / 10 min, 12 g / 10 min, 16 g / 10 min, The first ABS resin has a weight-average molecular weight of 150,000 to 200,000 g / mol, for example, 150,000 g / mol, 160,000 g / mol, 180,000 g / mol, 190,000 g / mol, 200,000 g / mol, etc., and a melt flow rate of 4 to 8 g / 10 min, for example, 4 g / 10 min, 6 g / 10 min, 7 g / 10 min, 8 g / 10 min, etc. Combining these two ABS resins can further improve the overall mechanical properties and impact strength of the ABS sheet. Furthermore, the first ABS resin is ABS 533UT, and the second ABS resin is ABS A290X.

[0075] The first ABS resin in the ABS composite middle layer may be present in an amount of 30 to 40 parts by weight, for example, 30, 32, 35, 38, or 40 parts. The second ABS resin may be present in an amount of 30 to 40 parts by weight, for example, 30, 32, 35, 38, or 40 parts.

[0076] In some embodiments, the nano-calcium carbonate material refers to an ultrafine powder of calcium carbonate with primary particles (primary particles) ranging in size from 1 to 100 nm. The nano-calcium carbonate in the middle layer of the ABS composite material may be present in an amount of 5 to 15 parts by weight, for example, 5, 8, 10, 12, or 15 parts.

[0077] Nano-calcium carbonate includes calcium carbonate surface-treated with stearic acid additives. Calcium carbonate is an important nanofiller, but its dispersibility in ABS is generally poor. However, calcium carbonate surface-treated with stearic acid additives can better control its dispersion, orientation, and interactions within the ABS matrix.

[0078] In some embodiments, the preparation of calcium carbonate surface-treated with a stearic acid additive includes: mixing a stearic acid additive and nano-calcium carbonate, dissolving the mixture in water, and then drying the mixture to obtain the stearic acid-treated calcium carbonate, i.e., pre-dispersed nano-calcium carbonate. This improves the hydrophobicity of the nano-calcium carbonate and enhances its compatibility with ABS resin. The stearic acid additive includes at least one of stearic acid (octadecanoic acid) or a stearate salt, including calcium stearate, zinc stearate, and magnesium stearate. The amount of stearic acid additive-treated nano-calcium carbonate can be 0.1% to 5% by weight of the nano-calcium carbonate.

[0079] Specifically, the preparation steps of calcium carbonate surface-treated with a stearic acid additive include: adding a stearic acid additive to nano-calcium carbonate in a certain proportion; stirring the mixture with a high-speed mixer; and ultrasonically treating the mixture for 1 minute; then dispersing the mixture in water, ultrasonically mixing it uniformly, removing moisture, and then drying it in a vacuum oven overnight to obtain pre-dispersed nano-calcium carbonate.

[0080] In some embodiments, a second antioxidant may or may not be added to the ABS composite interlayer as needed. Specifically, when a second antioxidant is added, it includes at least one of antioxidant 1010, antioxidant 168, antioxidant 1076, antioxidant 1330, antioxidant 1035, antioxidant 3144, antioxidant 1024, and antioxidant 126. This can improve the antioxidant properties of the ABS sheet, thereby extending the overall service life of the ABS sheet. The amount of the second antioxidant added can be very small, ranging from 0 to 0.05 parts by weight, for example, 0.01, 0.02, 0.01, 0.05, etc.

[0081] In some embodiments, a second lubricant may or may not be added to the ABS composite interlayer as needed. Specifically, when a lubricant is added, the second lubricant includes at least one of calcium stearate, talc, and polytetrafluoroethylene. Furthermore, the particle size of the first lubricant may be 500-10,000 mesh. The weight percentage of the second lubricant is 0-3 parts, such as 0.1 part, 1 part, 2 parts, 2.5 parts, etc.

[0082] In some embodiments, a compatibilizer may or may not be added to the ABS composite interlayer as needed. When a compatibilizer is added, it comprises at least one of a core-shell terpolymer of methyl methacrylate-butadiene-styrene, a polyolefin elastomer, and an ethylene-methyl acrylate copolymer. This further improves the compatibility of the ABS composite interlayer. The weight percentage of the compatibilizer is 0 to 5 parts, for example, 1 part, 1.2 parts, 1.4 parts, 2 parts, 3 parts, 4 parts, etc.

[0083] In some embodiments, the thickness of the ABS sheet is 0.2 to 1.0 mm. Furthermore, the ABS sheet for electronic component packaging carrier tape provided in this embodiment can be composed of an ABS composite material intermediate layer and antistatic surface layers (including upper and lower surface layers disposed opposite each other). In the ABS sheet, the thickness of the ABS composite material intermediate layer can account for greater than or equal to 80% of the total thickness of the ABS sheet.

[0084] Preparation method of ABS sheet

[0085] In a second aspect, an embodiment of the present application provides a method for preparing an ABS sheet, as shown in FIG1 , comprising the following steps:

[0086] S01: providing raw materials for the intermediate layer and the surface layer of the ABS composite material in the ABS sheet of the first aspect;

[0087] S02: Extrusion and compression molding are performed on the raw materials of the middle layer and the surface layer of the ABS composite material to obtain an ABS sheet.

[0088] In this embodiment, the raw materials for the intermediate layer and the surface layer of the ABS composite material are extruded and compression molded to produce an ABS sheet with uniformly dispersed carbon nanotubes on the surface layer. This preparation method is not only easy to process, but also, due to the interaction of the various components in the surface layer raw materials, the resulting ABS sheet has excellent antistatic properties and surface smoothness, making it suitable for use in the preparation of electronic packaging materials.

[0089] In step S01, the raw materials for the surface layer can be surface layer raw material particles composed of polystyrene, modified carbon nanotubes, toughening agent, inorganic filler, first lubricant (optional), and first antioxidant (optional). The raw materials for the ABS composite middle layer can be raw material particles composed of the first ABS resin, second ABS resin, nano-calcium carbonate, second antioxidant (optional), second lubricant (optional), and compatibilizer (optional). The specific types and amounts of these components have been detailed above.

[0090] In some embodiments, the preparation method of the raw material of the surface layer includes:

[0091] Corresponding weight portions of polystyrene, modified carbon nanotubes, toughening agent, inorganic filler, first lubricant and first antioxidant are mixed and melt-extruded to form granules to obtain raw materials for the surface layer.

[0092] Specifically, the surface layer raw material preparation steps include: first preparing a blend (polystyrene resin, toughening agent, and modified carbon nanotubes), then adding an inorganic filler, a first lubricant, and a second antioxidant, and melt blending using an internal mixer. Key process parameters include a mixing time of 15-25 minutes and a temperature of 220-240°C. These mixing temperatures and times effectively improve dispersibility. The second step uses a twin-screw extruder, where high-speed shearing of the screws disperses the modified carbon nanotubes in the resin matrix. The composite masterbatch is then cooled and pelletized. The extrusion temperature is 200-240°C, and the main engine speed is 400-1000 rpm / min. The twin-screw extruder melt-extrudes and pelletizes the pellets. The twin-screw extruder comprises, in order, a melting section, an extrusion section, a shearing section, a pressurizing section, a melt-degassing section, an extrusion section, a shearing section, a pressurizing section, a melt-degassing section, and a die. The set process conditions of the twin-screw extruder are as follows: melting section: 200~210℃; extrusion section: 215~225℃; shearing section: 220~230℃; pressurization section: 225~235℃; melt exhaust section: 225~235℃; extrusion section: 230~240℃; shearing section: 230~240℃; pressurization section: 225~235℃; melt exhaust section: 220~230℃; die head temperature: 215~235℃; main engine speed 400~1000rpm / min, vacuum degree ≤-0.05MPa.

[0093] In some embodiments, the method for preparing the raw materials of the ABS composite material middle layer includes:

[0094] The first ABS resin, the second ABS resin, nano calcium carbonate, the second antioxidant, the second lubricant and the compatibilizer are mixed and melt-extruded to form granules to obtain the raw material of the middle layer of the ABS composite material.

[0095] Specifically, the raw material preparation steps for the ABS composite middle layer include: first preparing pre-dispersed nano-calcium carbonate (i.e., nano-calcium carbonate surface-treated with a stearic acid additive); then drying the first ABS resin, the second ABS resin, the compatibilizer, and the pre-dispersed nano-calcium carbonate in a vacuum oven; and finally, granulating the first ABS resin, the second ABS resin, the compatibilizer, the pre-dispersed nano-calcium carbonate, the compatibilizer, the second lubricant, and the second antioxidant via twin-screw extrusion to produce an ABS composite material, which serves as the raw material for the middle layer. The pre-dispersed nano-calcium carbonate exhibits excellent dispersibility, and the extrusion process utilizes a variety of feeding methods and a screw combination with enhanced dispersion, resulting in uniform dispersion of the ABS substrate and the pre-dispersed nano-calcium carbonate filler.

[0096] Furthermore, the prepared ABS composite material has a melt index of 7-15 g / 10 min (220°C / 5 kg) and a density of 1.13-1.15 g / cm3. Specifically, the first ABS resin is ABS 533UT, and the second ABS resin is ABS A290X.

[0097] Furthermore, the ABS sheet preparation steps provided in the embodiment of the present application include: drying, in-mold composite extrusion, and rolling. Among them, the drying step includes: placing the raw materials for preparing the middle layer and the raw materials for the surface layer of the ABS composite material in the drying system of the casting machine and baking at 100~120℃ for 2~4h. The in-mold composite extrusion step includes: placing the dried raw materials for the middle layer and the surface layer of the ABS composite material into the feed cylinder respectively, and extruding through the same die by two extruders to form a three-layer composite sheet, the extrusion temperature of the middle layer is 200~240℃, the extrusion temperature of the upper and lower surface layers is 180~230℃, and the thickness of the extruded sheet is 0.2~1.0mm. The rolling step includes: rolling the initially formed composite sheet through a three-roll calender, cooling at a suitable temperature and adjusting the thickness and flatness of the sheet to ensure that the sheet does not stick to the roller, is shiny and has no flow marks and spots, to obtain an ABS sheet. Finally, the ABS sheet made after rolling can be sold directly to manufacturers as leather. The ABS sheet can also be made into a carrier tape by vacuum forming before it cools down, and then punching, slitting and winding of the finished product are performed.

[0098] Modified carbon nanotubes

[0099] In a third aspect, an embodiment of the present application provides a modified carbon nanotube, comprising a carbon nanotube and polybutadiene connected to the carbon nanotube via a chemical bond.

[0100] The modified carbon nanotubes formed by chemically grafting polybutadiene in the embodiment of the present application can improve the dispersibility of the carbon nanotubes. Such modified carbon nanotubes are used as fillers in the surface layer of the ABS sheet and can be evenly dispersed, thereby obtaining an antistatic ABS sheet with good surface conductivity uniformity.

[0101] In some embodiments, the modified carbon nanotube structure comprises:

[0102] CNT-NH-CO-NH-R-NH-CO-NH-(CH2CH=CHCH2) n -NH-CO-NH-R-NH-CO-NH-CNT; wherein CNT refers to carbon nanotube, and R includes at least one of a phenyl group and an alkyl group.

[0103] From the above structural formula, we can know that: polybutadiene (CH2CH=CHCH2) nThe carbon nanotubes are connected by two urea groups (-NH-CO-NH-) at both ends, forming a uniformly dispersed network of carbon nanotubes. n corresponds to the degree of polymerization of polybutadiene, specifically n = 20-200.

[0104] In some embodiments, the carbon nanotubes have an inner diameter of 1 to 4 nm, an outer diameter of 8 to 25 nm, a length of 1 to 100 μm, an aspect ratio of 5000 to 10000:1, and a specific surface area of ​​200 to 300 m 2 / g. The carbon nanotubes have better dispersibility and conductivity.

[0105] Preparation method of modified carbon nanotubes

[0106] In a fourth aspect, an embodiment of the present application provides a method for preparing modified carbon nanotubes, as shown in FIG2 , the method comprising:

[0107] T01: Mixing carbon nanotubes with amino groups on their surfaces and organic matter containing diisocyanate groups to carry out a first chemical reaction to obtain an intermediate product;

[0108] T02: The intermediate product is mixed with amino-terminated polybutadiene to carry out a second chemical reaction to obtain modified carbon nanotubes.

[0109] In this embodiment, carbon nanotubes with surface amino groups react with an organic compound containing diisocyanate groups, and then react with amine-terminated polybutadiene. Amine-terminated polybutadiene, which has terminal amine groups that are more reactive than hydroxyl groups, reacts more rapidly with isocyanate-reactive groups. This allows the carbon nanotubes and polybutadiene to be linked via groups containing -NH-CO-NH-, yielding modified carbon nanotubes grafted with polybutadiene. This preparation method is simple, and the resulting modified carbon nanotubes, when applied to the surface layer of ABS sheets, can significantly improve the surface conductivity uniformity and antistatic properties of the ABS sheets.

[0110] In some embodiments, the organic matter containing a diisocyanate group can be represented by R-(NCO)2, where R includes at least one of a phenyl group and an alkyl group, and can be specifically selected according to the type of organic matter, and ultimately corresponds to R in the modified carbon nanotube structure: -NH-CO-NH-R-NH-CO-NH-.

[0111] For example, the organic substance containing a diisocyanate group includes at least one of diphenylmethane diisocyanate (corresponding to R being diphenylmethane), diphenylpropane diisocyanate (corresponding to R being diphenylpropane), diphenylbutane diisocyanate (corresponding to R being diphenylbutane), toluene diisocyanate (corresponding to R being toluene), and dimethylbiphenyl diisocyanate (corresponding to R being dimethylbiphenyl).

[0112] Furthermore, the preparation steps of carbon nanotubes with amino functional groups include: mixing carbon nanotubes, 98% concentrated sulfuric acid by mass, and 38% concentrated hydrochloric acid by mass, and ultrasonicating at 40-65°C for 3-10 hours; cooling to room temperature (25-27°C) after the reaction, diluting with deionized water, centrifuging, and washing the solid product with deionized water and ethanol to a pH of 5-6; vacuum drying at 80-120°C for 6-24 hours, grinding to obtain carboxylated carbon nanotubes; adding a polyamine in an amount 2-4 times the weight of the carbon nanotubes, and then heating to 70-90°C and reacting for 1-5 hours to obtain carbon nanotubes with amino groups on the surface (CNT-NH2); wherein the polyamine is selected from one of ethylenediamine, triethylamine, diethylenetriamine, hexamethylenetetramine, and isophoronediamine.

[0113] The first chemical reaction involves the reaction of CNT-NH2 with -NCO in an organic compound containing diisocyanate groups. Specifically, CNT-NH2 is dispersed in an organic compound containing diisocyanate groups, R-(NCO)2, with the -NH2 to -NCO molar ratio being 1:2-6. The mixture is reacted at 80-120°C under nitrogen, washed, and dried to obtain an intermediate product. The reaction equation is as follows:

[0114] CNT-NH2+R-(NCO)2→CNT-NH-CO-NH-R-NCO (i.e., the intermediate product).

[0115] The second chemical reaction is the reaction of the intermediate product with amino-terminated polybutadiene (ATPB): CNT-NH-CO-NH-R-NCO, ATPB, and toluene are uniformly mixed and ultrasonically dispersed under nitrogen protection. The mixture is refluxed in an oil bath at 80-120°C for 10-60 hours, washed, and dried to obtain CNT grafted with amino-terminated polybutadiene, which is denoted as CNT-NH-CO-NH-R-NH-CO-NH-(CH2CH=CHCH2). n -NH-CO- NH-R-NH-CO-NH-CNT. Furthermore, the amount of the amine-terminated polybutadiene can be mixed according to the molar ratio of -NH2 in the amine-terminated polybutadiene to -NCO in the intermediate product of 1:(1~2). In the amine-terminated polybutadiene, the terminal amine substitution rate is greater than 98%. The terminal amine substitution rate can refer to the polybutadiene (CH2CH=CHCH2) n The percentage of the molecular end substituted by the active group -NH2 can be detected by conventional analytical chemistry methods (such as formaldehyde titration).

[0116] Through the first and second chemical reactions, the generated -NH-CO-NH-R-NH-CO-NH- is connected to the carbon nanotube and polybutadiene at both ends. R corresponds to the R in the organic compound R-(NCO)2 containing a diisocyanate group, while the polybutadiene in the raw material terminal amino polybutadiene corresponds to (CH2CH=CHCH2). n , n is the degree of polymerization of polybutadiene, specifically n=20~200; amine-terminated polybutadiene can be purchased from the market.

[0117] In this embodiment, functionalized carbon nanotubes with -NCO functional groups are synthesized by reacting an organic compound containing diisocyanate groups with amino-group-bearing carbon nanotubes. Amine-terminated polybutadiene is then grafted onto the carbon nanotube surface. The polybutadiene-modified carbon nanotubes exhibit significantly improved dispersibility. The physical properties of the ABS sheet in this embodiment were tested according to ASTM standards. The surface resistivity was measured using the DC comparison method, with the test equipment and measurement error meeting the requirements of GB / T 3048.5. This is described below with reference to specific examples.

[0118] Example 1

[0119] An ABS sheet comprises an ABS composite middle layer and two surface layers on opposite sides of the ABS composite middle layer; wherein the material weights of the ABS composite middle layer and the individual surface layers are shown in Table 1. The ABS sheet is prepared as follows:

[0120] S1. Raw material preparation:

[0121] Preparation of raw material particles for the surface layer:

[0122] (1) CNT-NH2 was dispersed in diphenylmethane diisocyanate (with a molar ratio of -NH2 to -NCO of 1:2), reacted at 120°C for 1 hour under nitrogen protection, and then washed and dried to obtain an intermediate product; the intermediate product and terminal amino polybutadiene (wherein the average polymerization degree of polybutadiene was 80 and the terminal amino substitution rate was greater than 98%) were dispersed in toluene, ultrasonically dispersed under nitrogen protection, refluxed at an oil bath temperature of 120°C for 20 hours, washed and dried to obtain modified carbon nanotubes.

[0123] (2) According to the formula in Table 1, the modified carbon nanotubes, HIPS, and toughening agent (butadiene rubber) were blended, and then an inorganic filler (talc), a first lubricant (calcium stearate), and a first antioxidant (antioxidant 1010) were added. The mixture was melt-blended using an internal mixer for 25 min at a temperature of 230°C. A twin-screw extruder was used for melt extrusion and granulation. The modified carbon nanotubes were dispersed in the matrix by high-speed shearing of the screws. The raw material particles of the surface layer were obtained by cooling and pelletizing. The extrusion temperature was 240°C, and the main engine speed was 1000 rpm / min. The twin-screw extruder sequentially includes a melting section, an extrusion section, a shearing section, a pressurizing section, a melt exhaust section, an extrusion section, a shearing section, a pressurizing section, a melt exhaust section, and a die. The set process conditions of the twin-screw extruder are as follows: melting section: 210°C; extrusion section: 225°C; shearing section: 230°C; pressurization section: 235°C; melt exhaust section: 235°C; extrusion section: 240°C; shearing section: 240°C; pressurization section: 235°C; melt exhaust section: 230°C; head temperature: 235°C; main engine speed 1000rpm / min, vacuum degree ≤-0.05MPa.

[0124] Preparation of raw material particles for the middle layer of ABS composite materials:

[0125] (1) Stearic acid and inorganic nano-calcium carbonate were mixed in a mass ratio of 5:100, and then stirred with a high-speed mixer for 10 minutes. The mixture was ultrasonically treated for 40 minutes. Water was then added and ultrasonically mixed for 1 hour. After removing the moisture, the mixture was dried in a vacuum oven at 150°C overnight to obtain pre-dispersed modified nano-calcium carbonate.

[0126] (2) According to the formula in Table 1, the first ABS resin (ABS-1, product model 533UT 757 0215A), the second ABS resin (ABS-2, product model 290X 770 3001MG2A), the compatibilizer (a core-shell structured terpolymer of methyl methacrylate-butadiene-styrene), and the pre-dispersed modified nano-calcium carbonate were dried in a vacuum oven at 80°C for 2 h; then mixed with the second lubricant (talcum powder) and the second antioxidant (antioxidant 168) and granulated by twin-screw extrusion to obtain the raw material particles of the middle layer of the ABS composite material.

[0127] The prepared two raw material particles were placed in the drying system of the casting machine and baked at 120°C for 4 hours.

[0128] S2, In-mold composite extrusion

[0129] The dried middle layer raw material particles and surface layer raw material particles are placed in the feeding cylinder respectively, and extruded through the same die by two extruders to form a three-layer composite sheet. The extrusion temperature of the middle layer is 240℃, and the extrusion temperature of the upper and lower surface layers is 220℃. The thickness of the extruded ABS sheet is 0.5mm (the thickness of the middle layer is 0.4mm, and the thickness of the upper and lower surface layers are 0.05mm respectively).

[0130] Example 2

[0131] An ABS sheet, compared with Example 1, differs in that the weight portions of the raw materials in the formula are different, see Table 1 for details.

[0132] Example 3

[0133] An ABS sheet, compared with Example 1, differs in that the weight portions of the raw materials in the formula are different, see Table 1 for details.

[0134] Example 4

[0135] An ABS sheet, compared with Example 1, differs in that the weight portions of the raw materials in the formula are different, see Table 1 for details.

[0136] Example 5

[0137] An ABS sheet, which differs from Example 2 in that the modified nano-calcium carbonate is replaced by unmodified nano-calcium carbonate (ie, the nano-calcium carbonate is not pretreated with a stearic acid additive), see Table 1 for details.

[0138] Comparative Example 1

[0139] An ABS sheet, which differs from Example 2 in that the modified carbon nanotubes are replaced with unmodified carbon nanotubes (i.e., carbon nanotubes not grafted with polybutadiene), see Table 1 for details.

[0140] Performance Testing

[0141] 0.5 mm thick ABS sheet samples prepared in Examples 1-5 and Comparative Example 1 were tested for physical properties, surface flatness, and surface resistivity. Physical properties were measured according to ASTM standards, while surface flatness was observed visually. Surface resistivity was tested using the DC comparison method, with the test equipment and measurement error meeting the requirements of GB / T 3048.5. The results are shown in Table 2.

[0142] Table 1 Weight parts of each component of the examples and comparative examples Item Component Example 1 Example 2 Example 3 Example 4 Example 5 Comparative Example 1 Surface HIPS 8095100909595 Surface modified carbon nanotubes 5111510110 Surface unmodified carbon nanotubes 0000011 Surface toughening agent 5810788 Surface inorganic filler 245344 Surface first lubricant 0.20.810.50.80.8 Surface first antioxidant 0.20.7 10.60.70.7 Middle layer ABS-1303640353636 Middle layer ABS-2303540383535 Middle layer modified nano-calcium carbonate 5111512011 Middle layer unmodified nano-calcium carbonate 0000110 Middle layer second antioxidant 0.050.070.10.060.070.07 Middle layer second lubricant 0.51.632.11.61.6 Middle layer compatibilizer 125322

[0143] Table 2 Effect data of embodiments and comparative examples Test items Example 1 Example 2 Example 3 Example 4 Example 5 Comparative example 1 Tensile strength MPa 4851 4750 4850 Flexural strength MPa 7886 83 858 184 Impact strength kJ / m 2 18.013.015.013.01212 Average surface resistivity Ω / Sq 3.4×10 7 2.8×10 4 7.5×10 5 3.7×10 4 6.1×10 4 2.5×10 7 Carrier tape surface resistivity Ω / Sq (front and back) 2.7×10 7 ~ 8.3×10 7 1.1×10 4 ~ 7.4×10 4 5.3×10 5 ~ 2.1×10 6 1.2×10 4 ~ 8.6×10 4 2.2×10 4 ~ 9.8×10 4 4.8×10 4 ~ 8.5×10 10Surface smoothnessSurface smooth without pittingSurface smooth without pittingSurface smooth without pittingSurface smooth without pittingSurface smooth without pittingSurface rough surface with pitting

[0144] As can be seen from the data in Table 2, Examples 1-5 of the present application use modified carbon nanotubes grafted with polybutadiene, which makes the carbon nanotubes more evenly dispersed, thereby making the range of surface resistivity variation of the ABS sheet small, the conductivity uniformity good, and the surface flatness good; while Comparative Example 1 uses unmodified carbon nanotubes, which have poor dispersion performance, making the surface of the ABS sheet rough, with pitting, and poor surface flatness, and the surface resistivity of the formed carrier tape is between 4.8×10 4 ~8.5×10 10 The Ω / Sq ratio varied over a wide range, significantly reducing the uniformity of electrical conductivity. Furthermore, by adjusting the component content in Example 2 (selecting appropriate amounts of modified carbon nanotubes and modified nano-calcium carbonate), not only was the average surface resistivity low, but the tensile and flexural strengths were also improved. However, Example 5, which used unmodified nano-calcium carbonate, exhibited reduced tensile strength, flexural strength, and impact strength compared to Example 2 due to poor filler compatibility.

[0145] 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. An ABS sheet, comprising an ABS composite material middle layer and a surface layer provided on at least one surface of the ABS composite material middle layer; wherein: The surface layer comprises the following components in parts by weight: Polystyrene 80-100 parts; 5-15 parts of modified carbon nanotubes; 2~10 parts of toughening agent; 1~5 parts of inorganic filler; The first lubricant 0~1 part; The first antioxidant 0~1 part; The modified carbon nanotubes include carbon nanotubes and polybutadiene connected to the carbon nanotubes via chemical bonds.

2. The ABS sheet according to claim 1, wherein: The modified carbon nanotube structural formula includes: CNT-NH-CO-NH-R-NH-CO-NH-(CH2CH=CHCH2)n-NH-CO-NH-R-NH-CO-NH-CNT; wherein CNT refers to carbon nanotubes, and R includes at least one of phenyl and alkyl.

3. The ABS sheet according to claim 1, wherein: The polystyrene comprises high impact polystyrene; and / or, The toughening agent includes at least one of butadiene rubber, isoprene rubber, styrene-butadiene-styrene rubber, styrene-isoprene-styrene rubber, acrylonitrile-butadiene rubber, styrene-butadiene rubber, ethylene-propylene rubber, and styrene-ethylene-butadiene-styrene rubber; and / or, The inorganic filler comprises at least one of calcium carbonate, barium sulfate, boron nitride, silicon dioxide, alum, titanium dioxide, calcium oxide, magnesium oxide, carbon black, talc and mica powder; and / or, The first lubricant comprises at least one of calcium stearate, talc and polyethylene wax; and / or, The first antioxidant includes at least one of antioxidant 1010 , antioxidant 168 , antioxidant 1076 , antioxidant 1330 , antioxidant 1035 , antioxidant 3144 , antioxidant 1024 , and antioxidant 126 .

4. The ABS sheet according to claim 1, wherein: The ABS composite material middle layer comprises the following components in parts by weight: 30-40 parts of the first ABS resin; 30-40 parts of the second ABS resin; 5-15 parts of nano calcium carbonate; The second antioxidant 0-0.05 parts; The second lubricant 0-3 parts; Compatibilizer 0~5 parts.

5. The ABS sheet according to claim 4, wherein: The first ABS resin has a weight average molecular weight of 150,000 to 200,000 g / mol and a melt flow rate of 8 to 18 g / 10 min; and / or, The weight average molecular weight of the second ABS resin is 150,000-200,000 g / mol, and the melt flow rate is 4-8 g / 10 min; and / or, The nano calcium carbonate comprises calcium carbonate surface treated with stearic acid additives; and / or The second lubricant comprises at least one of calcium stearate, talc and polytetrafluoroethylene; and / or, The second antioxidant includes at least one of antioxidant 1010, antioxidant 168, antioxidant 1076, antioxidant 1330, antioxidant 1035, antioxidant 3144, antioxidant 1024, and antioxidant 126; and / or, The compatibilizer includes at least one of a terpolymer of methyl methacrylate-butadiene-styrene, a polyolefin elastomer, and an ethylene-methyl acrylate copolymer.

6. The ABS sheet according to claim 1, wherein: The thickness of the ABS sheet is 0.2-1.0 mm; and / or, The thickness of the middle layer of the ABS composite material accounts for more than or equal to 80% of the total thickness of the ABS sheet.

7. A method for preparing an ABS sheet, wherein: include: Providing the raw material of the ABS composite material middle layer and the raw material of the surface layer in the ABS sheet according to any one of claims 1 to 6; The raw material of the middle layer of the ABS composite material and the raw material of the surface layer are formed by extrusion compression molding to obtain the ABS sheet.

8. The method for preparing an ABS sheet according to claim 7, wherein: The extrusion compression molding conditions include: the extrusion temperature of the raw material of the middle layer of the ABS composite material is 200-240°C, and the extrusion temperature of the raw material of the surface layer is 180-230°C.

9. The method for preparing an ABS sheet according to claim 7, wherein: The preparation method of the raw material of the surface layer comprises: The polystyrene, the modified carbon nanotubes, the toughening agent, the inorganic filler, the first lubricant and the first antioxidant are mixed and melt-extruded and granulated to obtain the raw material of the surface layer.

10. The method for preparing an ABS sheet according to claim 7, wherein: The preparation method of the raw material of the intermediate layer of the ABS composite material comprises: The first ABS resin, the second ABS resin, nano calcium carbonate, the second antioxidant, the second lubricant and the compatibilizer are mixed and melt-extruded and granulated to obtain the raw material of the intermediate layer of the ABS composite material.

11. A modified carbon nanotube, wherein: The invention comprises carbon nanotubes and polybutadiene connected with the carbon nanotubes through chemical bonds.

12. The modified carbon nanotube according to claim 11, wherein: The modified carbon nanotube structural formula includes: CNT-NH-CO-NH-R-NH-CO-NH-(CH2CH=CHCH2)n-NH-CO-NH-R-NH-CO-NH-CNT; wherein CNT refers to carbon nanotubes, and R includes at least one of phenyl and alkyl.

13. The modified carbon nanotube according to claim 11, wherein: The carbon nanotube has an inner diameter of 1-4 nm, an outer diameter of 8-25 nm, a length of 1-100 μm, an aspect ratio of 5000-10000:1, and a specific surface area of ​​200-300 m 2 / g.

14. A method for preparing modified carbon nanotubes, wherein: include: The carbon nanotubes with amino groups on the surface are mixed with an organic substance containing a diisocyanate group to carry out a first chemical reaction to obtain an intermediate product; The intermediate product is mixed with terminal amine polybutadiene to carry out a second chemical reaction to obtain modified carbon nanotubes.

15. The method for preparing modified carbon nanotubes according to claim 14, wherein: The organic substance containing a diisocyanate group includes at least one of diphenylmethane diisocyanate, diphenylpropane diisocyanate, diphenylbutane diisocyanate, toluene diisocyanate, and dimethylbiphenyl diisocyanate; and / or, The temperature of the first chemical reaction is 80-120° C.; and / or, The temperature of the second chemical reaction is 80-120°C.

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