Conductive particle, PC conductive composite material, preparation method, and plastic tape material

Abstract

Disclosed in the present application are a conductive particle, a PC conductive composite material, a preparation method and a plastic tape material. The conductive particle comprises a hard core body, a soft layer and a conductive layer, the soft layer coating the hard core body, and the conductive layer coating the surface of the soft layer. The conductive layer comprises carbon nanotubes, the carbon nanotubes being dispersed in the conductive layer. The core-shell structure of the different layers can enhance toughness, and improve the dispersity of the carbon nanotubes. Therefore, the conductive particle has good toughness, and good carbon nanotube dispersity, can uniformly conduct electricity, and can enhance toughness and avoid static electricity when being used for a plastic tape material. The preparation method comprises: carrying out first coating treatment of a paste containing a soft material on the surface of a hard core body so as to form a soft layer; and performing second coating treatment of a conductive material on the surface of the soft layer so as to form a conductive layer, thus obtaining a conductive particle, the conductive material comprising carbon nanotubes. The PC conductive composite material comprises PC and the conductive particles. The plastic tape material comprises a base layer and an anti-static layer, the anti-static layer containing the PC conductive composite material.

Description

Conductive particles, PC conductive composite material, preparation method, plastic leather Technical Field

[0001] The present application belongs to the technical field of composite materials, and specifically relates to conductive particles, PC conductive composite materials, preparation methods, and plastic leather materials. Background Art

[0002] Plastic leather, especially PC (polycarbonate) plastic leather, is a semi-finished sheet material used in the field of electronic packaging. The sheet can be made into carrier tape through a blister or slicing process. The carrier tape can be used in conjunction with a cover tape to carry and store electronic components such as resistors, capacitors, transistors, and diodes in the holes (also known as pockets) of the carrier tape, and the cover tape is sealed on top of the carrier tape to form a closed package to protect the electronic components from contamination and damage during storage and transportation. The leather or carrier tape can also be flame-retardant to better protect the electronic components. In addition, the leather or carrier tape also needs to have anti-static properties to protect the electronic components, so conductive additives are generally added to the plastic leather to make the plastic leather conductive and eliminate static electricity hazards in a timely manner.

[0003] Conductive additives used in existing plastic materials primarily include conductive carbon black, graphite, and carbon fiber. Carbon black is the mainstream filler due to its relatively low price and wide selection to meet conductivity requirements. However, to achieve an antistatic effect, high levels of carbon black are often added, which can significantly impact material performance and can easily lead to decarbonization during use, contaminating embedded components.

[0004] Carbon nanotubes with a high specific surface area only need to be added in a small amount to significantly improve the performance of plastic leather, such as mechanical properties, electrical conductivity and thermal stability, and the cleanliness of carbon nanotubes after application to plastic leather is higher than that of carbon black plastic leather. However, due to the high aspect ratio of carbon nanotubes, they are very easy to entangle and form agglomerates. During the preparation of composite materials, they are very easy to agglomerate into small particles, affecting the performance of the product and uneven conductivity. Therefore, the dispersion of carbon nanotubes in plastic leather composite materials has always been a bottleneck affecting the application of carbon nanotubes. In addition, when carbon nanotubes are directly applied to plastic leather, although the strength of the material will be improved, the toughness will also decrease, which is not conducive to processing, manufacturing and application scenarios. Technical issues

[0005] The purpose of this application is to overcome the above-mentioned deficiencies of the prior art and to provide a conductive particle, a PC conductive composite material, a preparation method, and a plastic leather material to solve the technical problem that the carbon nanotubes have poor dispersion, resulting in uneven conductivity and unsatisfactory toughness of the plastic leather material when applied to the plastic leather material. Technical Solutions

[0006] To achieve the above-mentioned application objectives, one aspect of the present application provides a conductive particle. The conductive particle of the present application comprises a hard core, a soft layer, and a conductive layer, wherein the soft layer covers the hard core, the conductive layer covers the surface of the soft layer facing away from the hard core, and the conductive layer comprises carbon nanotubes, which are dispersed in the conductive layer.

[0007] Furthermore, the particle size D50 of the hard core body is 0.1 to 3 μm.

[0008] Furthermore, the material of the hard core includes at least one of silicon dioxide, calcium carbonate, aluminum oxide, and magnesium oxide.

[0009] Furthermore, the hard core body includes a hard inner core and a flame retardant layer, and the flame retardant layer covers the hard inner core.

[0010] Furthermore, the surface of the hard inner core has a porous structure, and the flame retardant layer is partially embedded in the pores on the surface of the hard inner core.

[0011] Furthermore, the particle size D50 of the hard inner core is 0.1 to 2 μm.

[0012] Furthermore, the particle size D100 of the hard inner core is 1 to 4 μm.

[0013] Furthermore, the hard material of the hard inner core includes at least one of mesoporous silica, porous alumina, and porous magnesia.

[0014] Furthermore, the thickness of the flame retardant layer is 0.1 to 1 μm.

[0015] Furthermore, the flame retardant material of the flame retardant layer includes at least one of PTFE, FEP, PCTFE, and PVDF.

[0016] Furthermore, the mass ratio of the hard core to the soft layer is 2 to 5:1.

[0017] Furthermore, the thickness of the soft layer is 0.1 to 1 μm.

[0018] Furthermore, the soft material of the soft layer includes at least one of PET, silicone rubber, and styrene-butadiene rubber.

[0019] Furthermore, the thickness of the conductive layer is 0.1-1 μm.

[0020] Furthermore, the mass ratio of the carbon nanotubes to the conductive layer is 50% to 100%.

[0021] Furthermore, the carbon nanotubes are grafted onto the surface of the soft layer away from the hard core.

[0022] Furthermore, the aspect ratio of the carbon nanotubes is 5000-10000:1.

[0023] Furthermore, the inner diameter of the carbon nanotube is 1 to 2 nm.

[0024] Furthermore, the outer diameter of the carbon nanotube is 8 to 25 nm.

[0025] Furthermore, the length of the carbon nanotubes is 1 to 100 μm.

[0026] Furthermore, the specific surface area of ​​carbon nanotubes is 200-400 m 2 / g.

[0027] Furthermore, the ash content of the carbon nanotubes is ≤2%.

[0028] Furthermore, the particle size D90 of the conductive particles is 1 to 6 μm.

[0029] Furthermore, the conductive particles have a powder resistivity of 70 to 90 mΩ·cm.

[0030] Another aspect of the present application provides a method for preparing conductive particles. The method for preparing conductive particles of the present application comprises the following steps:

[0031] Performing a first coating treatment on the surface of the hard core body with a slurry including a soft material to form a soft layer;

[0032] A second coating treatment is performed on the surface of the soft layer away from the hard core body, comprising a conductive material, to form a conductive layer, thereby obtaining conductive particles; wherein the conductive material comprises carbon nanotubes.

[0033] Furthermore, the preparation method of the hard core body comprises the following steps:

[0034] The slurry including the flame retardant material is subjected to a third coating treatment on the surface of the hard inner core to form a flame retardant layer, thereby obtaining a hard core body.

[0035] Furthermore, the mass ratio of the hard inner core to the flame retardant material is 5 to 10:1.

[0036] Furthermore, the third coating process includes the following steps:

[0037] The flame retardant material, glacial acetic acid and solvent are prepared into a flame retardant material slurry, and the mixture slurry is prepared with the hard core. The pH value of the mixture slurry is adjusted to 5-7, and the hard core body is obtained after reaction.

[0038] Furthermore, the first coating process includes the following steps:

[0039] preparing a slurry of the soft material including the soft material, a solvent and a first surfactant;

[0040] After the slurry of the soft material is solidified on the surface of the hard core body, a soft layer is formed on the surface of the hard core body.

[0041] Furthermore, the first surfactant includes at least one of sodium lauryl sulfate, alkyl glucoside, and fatty acid glyceride.

[0042] Furthermore, the second coating process includes the following steps:

[0043] The carbon nanotubes are carboxylated, and the surface of the soft layer away from the hard core is aminoated. The carboxyl group and the amino group undergo amidation reaction through a coupling agent, so that the carbon nanotubes are grafted onto the surface of the soft layer.

[0044] Further, the carboxylation treatment comprises the following steps:

[0045] The carbon nanotubes were carboxylated by sulfuric acid and hydrochloric acid.

[0046] Furthermore, the amination treatment comprises the following steps:

[0047] The soft layer is subjected to an amination reaction by using an aminating agent, wherein the aminating agent includes at least one of N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane and 3-aminopropyltriethoxysilane.

[0048] Furthermore, the coupling agent includes at least one of diisopropylcarbodiimide, 1-hydroxybenzotriazole, and dimethylaminoethanol.

[0049] In another aspect of the present application, a PC conductive composite material is provided. The PC conductive composite material comprises PC resin and the conductive particles of the present application or the conductive particles prepared by the preparation method of the present application.

[0050] Furthermore, the PC conductive composite material includes the following components in parts by weight:

[0051] PC resin: 80-95 parts;

[0052] Conductive particles: 10-20 parts;

[0053] Auxiliary resin: 5-10 parts;

[0054] Inorganic filler: 1 to 5 parts;

[0055] Lubricant: 0.1-1 part;

[0056] Antioxidant: 0.1-1 part;

[0057] Compatibilizer: 0-2 parts;

[0058] Second surfactant: 0 to 2 parts.

[0059] Furthermore, the weight average molecular weight of the PC resin is 30,000 to 50,000 g / mol.

[0060] Furthermore, the melt index of the PC resin at 300° C. and 1.2 kg is 15 g / 10 min to 25 g / 10 min.

[0061] Furthermore, the auxiliary resin includes at least one of ABS resin and SBS resin.

[0062] Furthermore, the inorganic filler includes at least one of calcium carbonate, barium sulfate, talc, boron nitride powder, silicon dioxide, alum, titanium dioxide, calcium oxide, magnesium oxide, carbon black, and mica powder.

[0063] Furthermore, the inorganic filler includes barium sulfate and talc.

[0064] Furthermore, the lubricant includes at least one of calcium stearate, talc, and polyethylene wax.

[0065] Further, the antioxidant includes at least one of 1010, 168, 1076, 1330, 1035, 3144, 1024, and 126.

[0066] Furthermore, the compatibilizer includes maleic anhydride grafted methyl methacrylate.

[0067] Furthermore, the second surfactant includes at least one of sodium dodecyl sulfate, sodium dodecyl sulfonate, sodium dodecylbenzene sulfonate, sodium tetradecyl sulfate, sodium tetradecyl sulfonate, and sodium tetradecylbenzene sulfonate.

[0068] In another aspect of the present application, a method for preparing a PC conductive composite material is provided. The method for preparing the PC conductive composite material of the present application comprises the following steps:

[0069] The components including the PC conductive composite material of the present application are mixed to obtain the PC conductive composite material.

[0070] Furthermore, the mixing process includes the following steps:

[0071] The PC resin and the conductive particles are pretreated separately and then mixed together to obtain a PC conductive composite material.

[0072] Furthermore, the mixing process is carried out by a twin-screw extruder at an extrusion temperature of 260-300°C.

[0073] Furthermore, the method further comprises the following steps:

[0074] The obtained PC conductive composite material is granulated to obtain particles with a particle size of 2 to 3 mm.

[0075] In another aspect of the present application, a plastic leather material is provided. The plastic leather material of the present application comprises a base layer and an antistatic layer laminated with the base layer, wherein the antistatic layer comprises the PC conductive composite material of the present application, or comprises the PC conductive composite material prepared by the preparation method of the present application.

[0076] Furthermore, the antistatic layer has a thickness of 0.1 to 0.4 mm.

[0077] Furthermore, the thickness of the base layer is 1 to 1.6 mm. Beneficial effects

[0078] The conductive particles of this application are designed with different layers, using a core-shell structure to achieve toughness and improve the dispersion of carbon nanotubes. As a result, the conductive particles of this application have the beneficial effects of good toughness, good dispersion of carbon nanotubes, and uniform conductivity. They can be used in plastic leather to effectively toughen and prevent static electricity.

[0079] The present method for preparing conductive particles comprises first forming a soft layer coated on the surface of a hard core, and then forming a conductive layer coated on the surface of the soft layer to produce conductive particles with different layer structures. The resulting conductive particles have the beneficial effects of good toughness, good dispersion of carbon nanotubes, and uniform conductivity. They can be used in plastic leather to effectively provide toughness and anti-static properties. The preparation method is process-controllable, and the resulting conductive particles have stable structure and physicochemical properties.

[0080] The PC conductive composite material of the present application contains the conductive particles of the embodiment of the present application, which can give full play to the advantages of good toughness, good conductivity and uniform conductivity of the conductive particles. It can be compounded with PC resin to prepare a PC conductive composite material. Therefore, the plastic leather made of the PC conductive composite material of the present application can be well toughened and anti-static, and can be used for packaging and transportation of electronic components.

[0081] The present invention discloses a method for preparing a PC conductive composite material, which utilizes the advantages of conductive particles, such as good toughness, good conductivity, and uniform conductivity. The resulting PC conductive composite material can be used to effectively toughen plastic leather and provide antistatic properties, and can be used for packaging and transporting electronic components. The preparation method is process-controllable, and the resulting PC conductive composite material has stable physical and chemical properties.

[0082] The plastic leather material in the embodiment of the present application includes a base layer and an antistatic layer that are laminated, and the material of the antistatic layer includes the PC conductive composite material of the present application. Therefore, the plastic leather material has good toughness, good conductivity, and good conductive uniformity. It can be used for packaging and transportation of electronic components to protect electronic components well and can prevent static electricity. BRIEF DESCRIPTION OF THE DRAWINGS

[0083] In order to more clearly illustrate the specific implementation methods of the present application or the technical solutions in the prior art, the following is a brief introduction to the drawings required for use in the specific implementation methods or the description of the prior art. Obviously, the drawings described below are some implementation methods of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0084] FIG1 is a schematic diagram of the conductive particle structure according to an embodiment of the present application;

[0085] FIG2 is a schematic diagram of a conductive particle structure according to an embodiment of the present application;

[0086] FIG3 is a schematic diagram of the structure of a plastic leather material according to an embodiment of the present application;

[0087] FIG4 is a schematic diagram of the structure of a plastic leather material according to an embodiment of the present application;

[0088] The reference numerals are as follows:

[0089] 1-Hard core; 2-Soft layer; 3-Conductive layer; 4-Hard inner core; 5-Flame retardant layer; 6-Base layer; 7-Antistatic layer.

[0090] Implementation Methods of the Application

[0091] In order to make the technical problems, technical solutions and beneficial effects to be solved by this application more clearly understood, the present application is further described in detail below in conjunction with the 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.

[0092] 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.

[0093] In this application, "at least one" means one or more, and "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 items or plural items. For example, "at least one of a, b, or c", or "at least one of a, b, and c" can all mean: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can be single or multiple.

[0094] It should be understood that in the various embodiments of the present application, the size of the serial numbers of the above-mentioned processes does 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.

[0095] The terms used in the embodiments of the present application are for the purpose of describing specific embodiments only 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.

[0096] The weights of the relevant components mentioned in the examples of this application may not only refer to the specific content of each component, but also represent the weight ratio between the components. Therefore, as long as the content of the relevant components is proportionally enlarged or reduced according to the examples of this application, it is within the scope disclosed in the examples of this application. Specifically, the mass described in the examples of this application may be a mass unit known in the chemical industry, such as μg, mg, g, kg, etc.

[0097] 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.

[0098] On the one hand, as shown in Figure 1, an embodiment of the present application provides a conductive particle. The conductive particle of the embodiment of the present application includes a hard core 1, a soft layer 2, and a conductive layer 3. The soft layer 2 covers the hard core 1, and the conductive layer 3 is coated on the surface of the soft layer 2 facing away from the hard core 1. The conductive layer 3 includes carbon nanotubes, and the carbon nanotubes are dispersed in the conductive layer 3.

[0099] In the conductive particles of the embodiment of the present application, the hard core 1 refers to a core formed by a hard material. The hard material refers to a material with a hard texture, and the hardness should be greater than the hardness of the soft material contained in the soft layer 2. The core can be spherical, quasi-spherical, etc.

[0100] The soft layer 2 refers to a coating layer formed of a soft material and covers the hard core 1 . The soft material refers to a material with a soft texture, and its hardness should be less than the hard material contained in the hard core 1 .

[0101] The conductive layer 3 refers to a conductive coating layer that covers the soft layer 2. The materials contained therein can all be conductive materials, and the conductive materials can be at least one; it can also contain conductive materials and non-conductive materials, as long as the entire conductive layer 3 is conductive.

[0102] Wrapping means covering with a wrap.

[0103] The conductive particles in the embodiment of the present application are designed with a structure of different layers. From the inside to the outside, the particles are successively composed of a hard core 1, a soft layer 2 in the middle, and a conductive layer 3 on the outside. The particles are toughened by the mechanism of core-shell structure particles, and the core-shell layers are not easy to separate. Therefore, the conductive particles can be used in plastic leather materials. During the impact process, the internal hard core 1 can induce a large number of silver streaks, and the middle soft layer 2 can terminate the silver streaks (the silver streak phenomenon is that under the action of stress, stress concentration occurs in certain weak parts of the material, resulting in local plastic deformation and orientation, thereby appearing similar to fine grooves or "cracks" on the surface or inside of the material perpendicular to the stress direction). In this way, through the initiation of silver streaks in the hard core 1 inside the conductive particles and the termination of silver streaks in the soft layer 2, better impact resistance can be achieved, and application in plastic leather materials can significantly improve the toughness of plastic leather materials; and in the core-shell phase separation process, degranulation must first occur from the plastic leather material matrix, thereby forming cavities, inducing shear yield of the plastic leather material matrix and releasing more energy, significantly improving the toughness of the plastic leather material. Conductive layer 3 covers the surface of soft layer 2, and carbon nanotubes are dispersed in conductive layer 3, thereby achieving good dispersion of the carbon nanotubes in the conductive particles. Compared to the prior art, where carbon nanotubes are directly applied to plastic leather, which can cause agglomeration, dispersing the carbon nanotubes in conductive layer 3 of the conductive particles and then applying the conductive particles to the plastic leather prevents the carbon nanotubes on different conductive particles from interfering with or agglomerating with each other, thereby further improving the dispersion of the carbon nanotubes. Therefore, the conductive particles of the present embodiment have the beneficial effects of good toughness, good dispersion of carbon nanotubes, and uniform conductivity, and can be used in plastic leather to effectively toughen and prevent static electricity.

[0104] In the embodiment, the particle size D90 of the conductive particles is 1 to 6 μm. Examples include, but are not limited to, 1 μm, 3 μm, and 6 μm. These particle sizes D90 facilitate uniform dispersion of the conductive particles in the plastic material during application, and further improve the toughness of the conductive particles, the dispersion of carbon nanotubes, and the uniformity of conductivity.

[0105] In the embodiment, the conductive particles have a powder resistivity of 70 to 90 mΩ·cm. Examples include, but are not limited to, 70 mΩ·cm, 80 mΩ·cm, and 90 mΩ·cm. These powder resistivities provide excellent electrical conductivity and can be used in plastic leather to provide enhanced anti-static properties.

[0106] Hard core 1:

[0107] In the embodiment, the particle size D50 of the hard core 1 is 0.1 to 3 μm. Examples include, but are not limited to, 0.1 μm, 1 μm, and 3 μm. These particle sizes D50 of the hard core 1 are beneficial for improving the initiation and termination of silver streaking between the hard core 1 and the soft layer 2, further imparting a better toughening effect to the conductive particles.

[0108] In the embodiment, the material of the hard core 1 includes at least one of silicon dioxide, calcium carbonate, aluminum oxide, and magnesium oxide. Hard cores 1 made of these materials can improve the crazing initiation of the hard core 1 and the crazing termination of the soft layer 2. Furthermore, they can bond firmly with the soft layer 2, further enhancing the toughness of the conductive particles.

[0109] In the embodiment, as shown in FIG2 , the hard core body 1 includes a hard inner core 4 and a flame retardant layer 5, with the flame retardant layer 5 coating the hard inner core 4. By further dividing the hard core body 1 into the hard inner core 4 and the flame retardant layer 5 coating the hard inner core 4, the flame retardant effect of the conductive particles applied to plastic leather is improved, and the layer structure of the conductive particles is further enriched, which is conducive to further imparting a better toughening effect to the conductive particles.

[0110] In this embodiment, the surface of the hard core 4 is porous, with the flame-retardant layer 5 partially embedded in the pores on the surface of the hard core 4. This structure allows the hard core 4 and the flame-retardant layer 5 to be more tightly bonded, forming a layered hard core 1. Furthermore, when the conductive particles are impacted, the hard core 4 and the flame-retardant layer 5 within the hard core 1 can absorb some of the impact, further enhancing the toughness of the conductive particles.

[0111] In the embodiment, the particle size D50 of the hard core 4 is 0.1 to 2 μm. In the exemplary embodiment, D50 may include but is not limited to 0.1 μm, 0.5 μm, and 2 μm. In the embodiment, the particle size D100 of the hard core 4 is 1 to 4 μm. In the exemplary embodiment, D100 may include but is not limited to 1 μm, 2 μm, and 4 μm. The hard core 4 with these particle sizes D50 or D100 is conducive to the formation of a layered structure of the hard core 4 and the flame retardant layer 5. The hard core body 1 improves the silver streak initiation effect of the hard core body 1 and the silver streak termination effect of the soft layer 2, and further gives the conductive particles a better toughening effect.

[0112] In an embodiment, the hard material of the hard core 4 includes at least one of mesoporous silica, porous alumina, and porous magnesia. The hard core 4 of these hard materials has high strength, and the hard core body 1 formed in a layered structure in combination with the flame retardant layer 5 can improve the silver crazing initiation of the hard core body 1 and the silver crazing termination of the soft layer 2, further giving the conductive particles a better toughening effect. The porous surface structure of mesoporous silica, porous alumina, and porous magnesia facilitates the partial embedding of the flame retardant layer 5 into the pores on the surface of the hard core 4, further giving the conductive particles a better toughening effect. In the exemplary embodiment, the hard core 4 may include mesoporous silica.

[0113] In the embodiment, the thickness of the flame retardant layer 5 is 0.1 to 1 μm. Examples include, but are not limited to, 0.1 μm, 0.5 μm, and 1 μm. These thicknesses of the flame retardant layer 5 provide the conductive particles with a better flame retardant effect when used in plastic leather, and are beneficial for improving the bonding effect with the hard core 4 to form a layered hard core body 1, which further helps to give the conductive particles a better toughening effect.

[0114] In an embodiment, the flame retardant material of the flame retardant layer 5 includes at least one of PTFE (polytetrafluoroethylene), FEP (fluorinated ethylene propylene copolymer), PCTFE (polychlorotrifluoroethylene), and PVDF (polyvinylidene fluoride). The flame retardant layer 5 formed by these flame retardant materials imparts a better flame retardant effect to the conductive particles when used in plastic leather, and helps improve the bonding effect with the hard core 4 to form a layered hard core body 1, which further helps to impart a better toughening effect to the conductive particles. In this exemplary embodiment, the flame retardant material can be PTFE.

[0115] In the embodiment, the mass ratio of the hard core 1 to the soft layer 2 is 2 to 5:1. Examples include, but are not limited to, 2:1, 3:1, 4:1, and 5:1. These mass ratios are beneficial for enhancing the crazing initiation of the hard core 1 and the crazing termination of the soft layer 2, further imparting a better toughening effect to the conductive particles.

[0116] Soft layer 2:

[0117] In the embodiment, the thickness of the soft layer 2 is 0.1 to 1 μm. Examples include, but are not limited to, 0.1 μm, 0.5 μm, and 1 μm. These thicknesses of the soft layer 2 are beneficial for enhancing the crazing initiation of the hard core 1 and the crazing termination of the soft layer 2, further imparting a better toughening effect to the conductive particles.

[0118] In an embodiment, the soft material of the soft layer 2 includes at least one of PET (polyethylene terephthalate), silicone rubber, and styrene-butadiene rubber. The soft layer 2 formed by these soft materials is conducive to improving the silver streak initiation of the hard core 1 and the silver streak termination effect of the soft layer 2, further giving the conductive particles a better toughening effect. In addition, these soft materials have good compatibility with the carbon nanotubes and plastic leather matrix materials of the conductive layer 3, which is conducive to improving the dispersion of the carbon nanotubes. Therefore, the soft layer 2 of these soft materials is conducive to further giving the conductive particles a better toughening effect. In the exemplary embodiment, the soft material can be PET.

[0119] Conductive layer 3:

[0120] The conductive layer 3 may be made entirely of conductive materials, such as carbon nanotubes and conductive carbon black; or it may be a non-conductive material with conductive materials dispersed therein, such as carbon nanotubes dispersed in an organic material, or other conductive materials may be dispersed therein.

[0121] In the embodiment, the thickness of the conductive layer 3 is 0.1 to 1 μm. Examples include, but are not limited to, 0.1 μm, 0.5 μm, and 1 μm. These thicknesses of the conductive layer 3 are beneficial for improving the conductivity of the conductive layer 3, promoting uniform dispersion of the carbon nanotubes in the conductive layer 3, and improving the uniformity of the conductive particles. The use of conductive particles in plastic leather can better prevent static electricity.

[0122] In the embodiment, the mass ratio of carbon nanotubes to conductive layer 3 is 50% to 100%. Examples include, but are not limited to, 50%, 60%, 80%, and 100%. These carbon nanotube ratios are beneficial for improving the conductivity of conductive layer 3, promoting uniform dispersion of carbon nanotubes in conductive layer 3, and improving the uniformity of conductive particles. The use of conductive particles in plastic leather can provide better anti-static properties.

[0123] In the embodiment, carbon nanotubes are grafted onto the surface of the soft layer 2 facing away from the hard core 1. The carbon nanotubes grafted onto the surface of the soft layer 2 can be well dispersed in the conductive layer 3 and tightly bonded to the soft layer 2, which helps to improve the conductivity uniformity of the conductive particles. The use of conductive particles in plastic leather can better prevent static electricity.

[0124] In the embodiment, the aspect ratio of the carbon nanotube is 5000-10000:1; in the exemplary embodiment, it may include but is not limited to 5000:1, 6000:1, 8000:1, 10000:1. The inner diameter of the carbon nanotube is 1-2nm; in the exemplary embodiment, it may include but is not limited to 1nm, 1.3nm, 1.7nm, 2nm. The outer diameter of the carbon nanotube is 8-25nm; in the exemplary embodiment, it may include but is not limited to 8nm, 12nm, 18nm, 25nm. The length of the carbon nanotube is 1-100μm; in the exemplary embodiment, it may include but is not limited to 1μm, 20μm, 50μm, 70μm, 100μm. In the exemplary embodiment, the specific surface area is 200-400m 2 / g; may include but not limited to 200m 2 / g, 220m 2 / g, 250m 2 / g, 270m 2 / g、300m 2 / g、350m 2 / g、370m 2 / g, 400m 2 These carbon nanotubes with a certain aspect ratio, length, outer diameter, inner diameter, or specific surface area are beneficial for improving conductivity, uniformly dispersing in the conductive layer 3, reducing agglomeration, and improving the conductivity uniformity of the conductive particles. The use of the conductive particles in plastic leather can better prevent static electricity.

[0125] In the embodiment, the ash content of the carbon nanotubes is ≤2%. Such carbon nanotubes with high ash content have high cleanliness and are also beneficial for improving conductivity, so they are beneficial for ensuring the cleanliness of plastic belts after being applied to plastic leather materials, and can be used to package electronic components for storage or transportation.

[0126] On the other hand, accordingly, an embodiment of the present application further provides a method for preparing the above-mentioned conductive particles. The method for preparing the conductive particles comprises the following steps:

[0127] S10. A slurry comprising a soft material is first coated on the surface of the hard core body 1 to form a soft layer 2;

[0128] S20. Performing a second coating treatment on the surface of the soft layer 2 away from the hard core 1 including a conductive material to form a conductive layer 3 to obtain conductive particles; wherein the conductive material includes carbon nanotubes.

[0129] The preparation method of the present invention first forms a soft layer 2 coated on the surface of a hard core 1, and then forms a conductive layer 3 coated on the surface of the soft layer 2 to produce conductive particles with different layer structures. The resulting conductive particles have the beneficial effects of good toughness, good carbon nanotube dispersion, and uniform conductivity. They can be used in plastic leather to effectively toughen and prevent static electricity. The preparation method is process-controllable, and the structure and physicochemical properties of the resulting conductive particles are stable.

[0130] Step S10 is a step of forming a soft layer 2 on the surface of the hard core 1. The hard core 1 may include at least one of silicon dioxide, calcium carbonate, aluminum oxide, and magnesium oxide. The particle size D50 of the hard core 1 is 0.1 to 3 μm.

[0131] In the embodiment, a hard core body 1 may be prepared first in step S10. The hard core body 1 may be a hard core 4 coated with a flame retardant layer 5. The preparation method of the hard core body 1 includes the following steps:

[0132] S11 . Performing a third coating treatment on the surface of the hard core 4 with a slurry including a flame retardant material to form a flame retardant layer 5 , thereby obtaining a hard core body 1 .

[0133] Step S11 can produce a layered hard core body 1 with a flame-retardant layer 5 covering a hard core 4, which is beneficial for improving the flame retardant effect of the conductive particles when applied to plastic leather materials and enriching the layer structure of the conductive particles. This preparation method is beneficial for further giving the conductive particles a better toughening effect. The flame retardant material can include at least one of PTFE, FEP, PCTFE, and PVDF, and the hard core 4 can include at least one of mesoporous silica, porous alumina, and porous magnesium oxide. The particle size D50 of the hard core 4 is 0.1 to 2 μm, and the particle size D100 is 1 to 4 μm.

[0134] In this embodiment, the mass ratio of the hard core 4 to the flame retardant material is 5 to 10:1. In exemplary embodiments, the mass ratio may include, but is not limited to, at least one of 5:1, 6:1, 8:1, and 10:1. These mass ratios enable the hard core 4 and the flame retardant material to be produced in an appropriate mass ratio, resulting in a layered hard core 1. This improves the flame retardant effect of the conductive particles when applied to plastic leather, enriches the layer structure of the conductive particles, and further enhances the toughening effect of the conductive particles.

[0135] In the embodiment, the third coating process in step S11 includes the following steps:

[0136] A flame retardant material, glacial acetic acid and a solvent are prepared into a flame retardant material slurry, and the mixture slurry is prepared with the hard core 4 to form a mixture slurry. The pH value of the mixture slurry is set at 5-7, and the hard core body 1 is obtained after the reaction.

[0137] The third coating treatment in this step can produce a hard core body 1 in which the flame retardant layer 5 tightly coats the hard inner core 4, which is beneficial to improving the flame retardant effect of the conductive particles applied to plastic leather materials and enriching the layer structure of the conductive particles. This preparation method is beneficial to further give the conductive particles better toughening effect.

[0138] In an exemplary embodiment, PTFE and water are first prepared into a dispersion with a solid content of 60%. 100 parts by weight of this dispersion is poured into a thermostatically controlled stirred tank and stirred at a set temperature of 20-25°C and a stirring speed of 300-600 rpm. Glacial acetic acid is then added to the stirred tank to prepare a PTFE pre-dispersion. Silica powder is then added to a planetary ball mill. Deionized water is added and mixed thoroughly, and the mixture is poured into the planetary ball mill, where the volume ratio of water to the milling liquid is 10%-50%. The ball mill is turned on and milled at a rotational angular velocity of 600-800 rpm and an orbital angular velocity of 200-400 rpm for 2-3 hours to prepare a silica slurry (wherein the silica particle size is 0.1 μm ≤ D50 ≤ 2 μm and 1 μm ≤ D100 ≤ 4 μm). Finally, the silica slurry is slowly added to the PTFE pre-dispersion liquid, and glacial acetic acid is added at the same time to maintain the pH value of the mixed dispersion in the range of 5 to 7. After completion, stirring is continued for 30 to 60 minutes. After drying, the PTFE-loaded mesoporous silica, i.e., the flame retardant layer 5, is obtained to coat the hard core 4 as the hard core body 1.

[0139] After providing the hard core body 1, further performing a first coating treatment on the surface of the hard core body 1 to form a soft layer 2 may include the following steps:

[0140] S12. A slurry comprising a soft material, a solvent and a first surfactant is prepared into a soft material;

[0141] S13 . After the slurry of the soft material is solidified on the surface of the hard core body 1 , a soft layer 2 is formed on the surface of the hard core body 1 .

[0142] The soft material in step S12 may include at least one of PET, silicone rubber, and styrene-butadiene rubber, and the solvent may be acetone, ethyl acetate, ethanol, isopropyl alcohol, etc., which is used to disperse the soft material and the first surfactant. The first surfactant may include at least one of sodium lauryl sulfate, alkyl glucoside (APG), and fatty acid glyceride, which is used to improve the bonding effect between the soft material and the surface of the hard core body 1. After curing in step S13, a soft layer 2 is formed on the surface of the hard core body 1. This method is conducive to preparing conductive particles with the hard core body 1 and the soft layer 2 tightly bonded. In an exemplary embodiment, 100 parts by weight of PET can be weighed first, heated and melted in a high-temperature reaction equipment, and then the hard core body 1 is added thereto. The mass ratio of the hard core body 1 to PET can be 2 to 5:1. Then, the solvent and the first surfactant are added, the mixed slurry is stirred and dispersed, and finally dried to remove the solvent so that the slurry of the soft material is solidified on the surface of the hard core body 1, and the soft layer 2 is coated on the surface of the hard particles.

[0143] Step S20: is a step of forming a conductive layer 3 from a conductive material and finally obtaining conductive particles. The conductive material can be formulated into a slurry and solidified on the surface of the soft layer 2 away from the hard core 1 to form a conductive layer 3. The conductive material includes carbon nanotubes, and the carbon nanotubes can also be pretreated before use. For example, in an embodiment, the pre-dispersion treatment can be performed by ultrasonic dispersion treatment. Pre-dispersed carbon nanotubes obtained by pre-dispersion treatment can further improve the dispersion effect of the carbon nanotubes, thereby improving the dispersibility of the carbon nanotubes in the obtained product and improving the performance of the obtained product. In an embodiment, the second coating treatment can include the following steps:

[0144] S21. Carboxylating the carbon nanotubes;

[0145] S22. The surface of the soft layer 2 away from the hard core 1 is subjected to amino treatment;

[0146] S23. A coupling agent is used to cause an amidation reaction between the carboxyl group and the amino group, so that the carbon nanotubes are grafted onto the surface of the soft layer 2 .

[0147] In an embodiment, the carboxylation treatment in step S21 includes carboxylating the carbon nanotubes using sulfuric acid and hydrochloric acid. In an exemplary embodiment, the carbon nanotubes can be mixed with 98% by mass concentrated sulfuric acid and 38% by mass concentrated hydrochloric acid, then ultrasonically treated at 40-65°C for 3-10 hours. After the reaction is complete and cooled to room temperature, the mixture is diluted with deionized water and centrifuged. The solid product is then washed with deionized water and ethanol to a pH of 5-6. The solid product is then vacuum dried at 80-120°C for 6-24 hours and ground into powder to obtain the carboxylated carbon nanotubes.

[0148] The amination treatment in step S22 includes performing an amination reaction on the soft layer 2 using an amination agent. In an exemplary embodiment, the amination agent can be added to deionized water and stirred; then, the hard core 1 coated with the soft layer 2 is added and stirred for 1 to 4 hours to cause an amination reaction on the surface of the soft layer 2; the amination agent includes at least one of N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane and 3-aminopropyltriethoxysilane (APTES).

[0149] In step S23, the carboxylated carbon nanotubes obtained in step S21 and step S22 and the hard core body 1 coated with the amino soft layer 2 can be provided in a ratio of carboxyl groups to amino groups close to 1:1. Specifically, the carboxylated carbon nanotubes and the hard core body 1 coated with the amino soft layer 2 can be weighed in a mass ratio of 1:2 to 12, and the prepared carboxylated carbon nanotubes are added to a DMF solution and ultrasonically oscillated for 15 to 60 minutes to obtain a mixture 1; the prepared hard core body 1 coated with the amino soft layer 2 is added to another DMF solution and ultrasonically oscillated for 30 to 90 minutes to obtain a mixture 2; the mixture 1 and the mixture 2 are mixed, and a coupling agent is added, and the mixture is stirred and reacted at 75 to 125° C. for 2 to 8 hours to fully complete the amidation reaction, filtered, and the solid product is washed with deionized water and ethanol, and vacuum dried at 60 to 110° C. for 5 to 10 hours to obtain conductive particles. The coupling agent includes at least one of diisopropylcarbodiimide, 1-hydroxybenzotriazole, and dimethylaminoethanol, which is used to promote the amidation reaction between the amino group and the carboxyl group, and can reduce the reaction temperature and accelerate the reaction time.

[0150] By pre-treating the carbon nanotubes in steps S21, S22, and S23, followed by an amidation reaction using a coupling agent, the carbon nanotubes are firmly grafted onto the surface of the soft layer 2 to form a conductive layer 3. Furthermore, the carbon nanotubes are well dispersed within the conductive layer 3, thereby improving the uniformity of the conductive particles. The conductive particles can be used in plastic leather materials to provide enhanced anti-static properties. Finally, the resulting conductive particles can be ground to obtain a powder with a particle size of 1 μm ≤ D90 ≤ 6 μm for later use.

[0151] In another aspect, the present invention also provides a PC conductive composite material. The PC conductive composite material includes PC resin and conductive particles according to the present invention or conductive particles prepared by the preparation method according to the present invention.

[0152] The PC conductive composite material of the embodiment of the present application contains the conductive particles of the embodiment of the present application, which can give full play to the advantages of good toughness, good conductivity, and uniform conductivity of the conductive particles. It can be compounded with PC resin to prepare a PC conductive composite material. Therefore, the plastic leather prepared from the PC conductive composite material of the embodiment of the present application can be well toughened and anti-static, and can be used for packaging and transportation of electronic components.

[0153] In the embodiment, the PC conductive composite material of the present application includes the following components in parts by weight:

[0154] PC resin: 80-95 parts;

[0155] Conductive particles: 10-20 parts;

[0156] Auxiliary resin: 5-10 parts;

[0157] Inorganic filler: 1 to 5 parts;

[0158] Lubricant: 0.1-1 part;

[0159] Antioxidant: 0.1-1 part;

[0160] Compatibilizer: 0-2 parts;

[0161] Second surfactant: 0 to 2 parts.

[0162] The PC conductive composite material of the embodiment of the present application contains the conductive particles of the embodiment of the present application. When combined with PC resin and other components, the conductive particles can have the advantages of good toughness, good conductivity, and uniform conductivity. Therefore, the plastic leather made of the PC conductive composite material of the embodiment of the present application can be well toughened and anti-static, and can be used for packaging and transportation of electronic components.

[0163] PC resin: PC resin can be used as the main material of plastic leather materials and compounded with conductive particles to make PC conductive composite materials. In the embodiment, the weight average molecular weight of the PC resin is 30,000 to 50,000 g / mol, so as to have better processing performance, mechanical properties and thermal stability. The melt index of the PC resin at 300°C and 1.2 kg is 15 g / 10min to 25 g / 10min, so as to have better processing performance and ensure that the composite material is suitable for application in plastic leather materials. In the exemplary embodiment, the weight parts of PC resin may include but are not limited to 80 parts, 85 parts, 90 parts, and 95 parts.

[0164] Conductive particles: The conductive particles include the conductive particles of the embodiments of this application, or include the conductive particles produced by the preparation methods of the embodiments of this application. Thus, the PC conductive composite material of the embodiments of this application has the beneficial effects of good toughness, good conductivity, and good conductive uniformity. The weight content of the conductive particles may include, but is not limited to, 10 parts, 13 parts, 15 parts, 18 parts, and 20 parts.

[0165] Auxiliary resin: This can further improve the processing, mechanical properties, and thermal stability of the PC conductive composite material. In one embodiment, the auxiliary resin includes at least one of ABS resin (acrylonitrile-butadiene-styrene copolymer resin) and SBS resin (a triblock copolymer resin composed of styrene and butadiene). In an exemplary embodiment, ABS resin can be used. The weight ratio of the auxiliary resin can include, but is not limited to, 5 parts, 7 parts, 8 parts, or 10 parts.

[0166] Inorganic fillers can improve the strength, wear resistance, and heat resistance of the PC conductive composite material. In one embodiment, the inorganic filler includes at least one of calcium carbonate, barium sulfate, talc, boron nitride powder, silica, alum, titanium dioxide, calcium oxide, magnesium oxide, carbon black, and mica powder. In an exemplary embodiment, the inorganic fillers include barium sulfate and talc, which provide high dimensional stability and improve the heat resistance and brightness of the PC conductive composite material. The amount of inorganic filler by weight may include, but is not limited to, 1 part, 3 parts, or 5 parts.

[0167] Lubricants can improve fluidity, promote resin melting, and prevent adhesion. In the embodiments, the lubricant can be a high-temperature and migration-resistant lubricant, so that the resulting material does not precipitate or migrate at high temperatures. The lubricant includes at least one of calcium stearate, talc, and polyethylene wax. The weight ratio can include, but is not limited to, 0.1, 0.3, 0.5, 0.7, and 1 part.

[0168] Antioxidants: Antioxidants extend the service life of the PC conductive composite material and improve thermal stability and processing performance. In embodiments, the antioxidant includes at least one of 1010, 168, 1076, 1330, 1035, 3144, 1024, and 126. The weight content may include, but is not limited to, 0.1, 0.3, 0.5, 0.7, or 1 part.

[0169] Compatibilizer: This improves the processing properties of the PC conductive composite material and enhances the compatibility of its components. In this embodiment, the compatibilizer comprises maleic anhydride grafted methyl methacrylate. The weight percentages may include, but are not limited to, 0.5, 1, 1.5, and 2 parts. A value of 0 parts means that no compatibilizer is required in the PC conductive composite material.

[0170] A second surfactant can improve the processing properties of the PC conductive composite material and enhance the compatibility of its components. In embodiments, the second surfactant includes at least one of sodium dodecyl sulfate, sodium dodecyl sulfonate, sodium dodecylbenzene sulfonate, sodium tetradecyl sulfate, sodium tetradecyl sulfonate, and sodium tetradecylbenzene sulfonate. The amount by weight may include, but is not limited to, 0.5, 1, 1.5, or 2 parts. A value of 0 parts means that no second surfactant is required in the PC conductive composite material.

[0171] On the other hand, accordingly, the embodiments of the present application also provide a method for preparing the PC conductive composite material described above. The method for preparing the PC conductive composite material comprises the following steps:

[0172] Step S30: Mix the components of the PC conductive composite material according to the embodiment of the present application to obtain a PC conductive composite material.

[0173] The method for preparing the PC conductive composite material of the present invention can produce the PC conductive composite material of the present invention. Leveraging the advantages of the conductive particles' excellent toughness, good conductivity, and uniform conductivity, the resulting PC conductive composite material can be used to effectively toughen plastic leather and provide antistatic properties, and can be used for packaging and transporting electronic components. The preparation method is process-controllable, and the resulting PC conductive composite material has stable physical and chemical properties.

[0174] In the embodiment, the mixing process in step S30 includes the following steps:

[0175] The PC resin and conductive particles are pretreated separately and then mixed together to obtain a PC conductive composite material. The preparation method of this step can improve the dispersibility of each component and improve the toughness and conductive uniformity of the obtained PC conductive composite material. The mixing process can be carried out by a twin-screw extruder at an extrusion temperature of 260-300°C. In an exemplary embodiment, the conductive particles can be weighed and poured into a high-speed mixer, and then the weighed lubricant and antioxidant are poured into the mixer according to the proportion, and the mixture is stirred at a speed of 100-300 r / min for 2-5 minutes, and the mixture is stirred and mixed to obtain a first premix. The inorganic filler is then poured into the high-speed mixer and stirred at a high speed of 100-300 r / min for 10-15 minutes. A certain amount of PC resin and the first premix are then weighed and poured into the high-speed mixer at a speed of 100-300 r / min for 10-15 minutes, and the mixture is stirred and mixed to obtain a second premix. The second premix is ​​placed into the main feed port of a twin-screw extruder. The materials are then melt-mixed in the twin-screw extruder at an extrusion temperature of 260-300°C and a main engine speed of 350-500 rpm. The melt is pulled out through a shaped die at a constant speed and then cooled in a water tank to obtain a PC conductive composite material. Finally, it can be granulated by air drying and pelletizing to produce pellets with a particle size of 2-3 mm for later use. The particle size here refers to the actual particle size, not the statistical particle size.

[0176] On the other hand, as shown in Figures 3 and 4, the present invention also provides a plastic leather material. The plastic leather material of the present invention includes a base layer 6 and an antistatic layer 7 laminated with the base layer 6. The material of the antistatic layer 7 includes the PC conductive composite material of the present invention, or includes the PC conductive composite material prepared by the preparation method of the present invention.

[0177] The plastic leather material of the embodiment of the present application includes a base layer 6 and an antistatic layer 7 which are stacked together, and the material of the antistatic layer 7 includes the PC conductive composite material of the embodiment of the present application. Therefore, the plastic leather material has good toughness, good conductivity, and good conductive uniformity. It can be used for packaging and transporting electronic components to protect the electronic components well and can prevent static electricity.

[0178] The material of the base layer 6 can be PC resin, the number of base layers 6 can be more than one, and the thickness of each base layer 6 can be independently 1 to 1.6 mm, and in the exemplary embodiment, it can include but is not limited to 1 mm, 1.2 mm, 1.4 mm, and 1.6 mm. In the embodiment, the number of antistatic layers 7 can be more than one, and the thickness of each antistatic layer 7 can be independently 0.1 to 0.4 mm, and in the exemplary embodiment, it can include but is not limited to 0.1 mm, 0.2 mm, and 0.4 mm. The stacking combination method can be as shown in Figure 3, that is, base layer 6-antistatic layer 7-base layer 6 are stacked in sequence to form a sandwich structure, or as shown in Figure 4, that is, antistatic layer 7-base layer 6-antistatic layer 7 are stacked in sequence to form a sandwich structure.

[0179] The preparation method can be extrusion molding. In an exemplary embodiment, the PC conductive composite material can first be placed in the drying system of a casting machine and baked at 100-120°C for 2-4 hours. The baked PC conductive composite material and the base layer 6 material are placed in the corresponding positions and fed by an automatic feeder. The material enters the casting machine and is extruded into a sheet through intramold composite extrusion, or extruded into a carrier tape on a pelletizer, and then punched, slit, and wound up. The initially formed sheet is then rolled on a three-roll calender. The extruded sheet is 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 has no flow marks or spots. This is the plastic leather. The plastic leather can be used directly as a product, or it can be vacuum-formed to form a semi-finished carrier tape while the sheet is still cool. Finally, punching, slitting, and winding the finished product are performed to obtain the carrier tape. The carrier tape can be used to package electronic components and protect them during transportation and storage.

[0180] The following uses a number of specific embodiments to illustrate the conductive particles, PC conductive composite materials, preparation methods, plastic leather materials, etc. of the embodiments of the present application.

[0181] 1. Conductive particles and their preparation method:

[0182] Example A1

[0183] This embodiment provides a conductive particle and a preparation method thereof.

[0184] The structure of the conductive particles is shown in Figure 2, which is a multi-layer core-shell structure. From the inside to the outside, it consists of a hard core, a flame retardant layer, a soft layer, and a conductive layer. The hard core is mesoporous silica, the flame retardant layer is PTFE, the soft layer is PET, and the conductive layer is carbon nanotubes.

[0185] The preparation method of the PC conductive composite material in this embodiment includes the following steps:

[0186] S1. Preparation of hard core

[0187] First, PTFE and water are prepared into a dispersion with a solid content of 60%. 100 parts by weight are poured into a constant temperature stirring kettle for stirring, with the temperature set at 22°C and the stirring speed at 600 rpm. Glacial acetic acid is added to the stirring kettle to prepare a PTFE pre-dispersion. Then 480 parts by weight of silica powder are added to a planetary ball mill. Deionized water is added and mixed evenly, and the mixture is poured into a planetary ball mill, wherein the volume ratio of water to the ball milling liquid is 30%. The ball mill is turned on, and the rotation angular velocity is set to 700 rpm and the revolution angular velocity is set to 300 rpm for grinding for 3 hours to prepare silica slurry (wherein the particle size D50 of silica is 1 μm and D100 is 2 μm). Finally, the silica slurry is slowly added to the PTFE pre-dispersion, and glacial acetic acid is added to maintain the pH value of the mixed dispersion at 6. After completion, stirring is continued for 60 minutes. After drying, mesoporous silica loaded with PTFE is obtained as a hard core, which is recorded as SiO2@PTFE.

[0188] S2. Formation of a soft layer covering the hard core

[0189] First, 100 parts by weight of PET are weighed and melted in a high-temperature reaction device. Then, a hard core is added thereto. The mass ratio of the hard core to PET can be 3:1. Then, a solvent and alkyl glucoside are added. Finally, the mixed slurry is stirred and dispersed. Finally, the solvent is dried to remove the solvent so that the slurry of the soft material solidifies on the surface of the hard core. The soft layer is coated on the surface of the hard particles, which is recorded as SiO2@PTFE@PET.

[0190] S3. Forming a conductive layer covering a soft layer

[0191] First, carbon nanotubes, 98% concentrated sulfuric acid, and 38% concentrated hydrochloric acid were mixed, and then ultrasonically dispersed at 60°C for 8 hours. After the reaction was completed and cooled to room temperature, the mixture was diluted with deionized water and centrifuged. The solid product was washed with deionized water and ethanol to a pH of 5.5. The mixture was vacuum dried at 100°C for 18 hours and ground into powder to obtain carboxylated carbon nanotubes.

[0192] Then, N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane was added to deionized water and stirred; then, the finished SiO2@PTFE@PET prepared in step S2 was added and stirred for 4 hours to aminize the surface of the soft layer;

[0193] Finally, carboxylated carbon nanotubes and amino SiO2@PTFE@PET in a mass ratio of 1:4 were taken, and the prepared carboxylated carbon nanotubes were added to DMF solution and ultrasonically oscillated for 50 minutes to obtain mixture 1; the prepared amino SiO2@PTFE@PET was added to another DMF solution and ultrasonically oscillated for 30 to 90 minutes to obtain mixture 2; mixture 1 and mixture 2 were mixed, and diisopropylcarbodiimide and 1-hydroxybenzotriazole were added, and the mixture was stirred and reacted at 100°C for 6 hours, filtered, and the solid product was washed with deionized water and ethanol, and vacuum dried at 100°C for 8 hours to allow the amino group and the carboxyl group to undergo amidation reaction, and finally conductive particles were obtained.

[0194] Example A2

[0195] This embodiment provides a conductive particle and a preparation method thereof.

[0196] The only difference between the conductive particles and Example A1 is that the particle size D50 of the silicon dioxide hard core is 4 μm and D100 is 7 μm.

[0197] The preparation method of the PC conductive composite material in this embodiment is different from that in Example A1 only in that the hard silicon dioxide powder in step S1 is changed to have a particle size D50 of 4 μm and D100 of 7 μm.

[0198] Example A3

[0199] This embodiment provides a conductive particle and a preparation method thereof.

[0200] The only difference between the conductive particles in Example A1 is that the mass ratio of the hard core to the soft layer is 1:1.

[0201] The preparation method of the PC conductive composite material in this embodiment is different from that in Example A1 only in that the mass ratio of the hard core to PET in step S2 is changed to 1:1.

[0202] Example A4

[0203] This embodiment provides a conductive particle and a preparation method thereof.

[0204] The conductive particles differ from Example A1 only in that they do not include a flame retardant layer; their structure is shown in FIG1 , which is a multi-layer core-shell structure, comprising, from the inside to the outside, a hard core, a soft layer, and a conductive layer, wherein the hard core is calcium carbonate, the soft layer is PET, and the conductive layer is carbon nanotubes.

[0205] The preparation method of the PC conductive composite material in this embodiment differs from that in embodiment A1 only in that step S1 is not included, and steps S2 and S3 are directly performed using calcium carbonate as a hard core to obtain conductive particles.

[0206] Comparative Example A1

[0207] This comparative example provides a conductive particle and a preparation method thereof.

[0208] The structure of the conductive particles is a core-shell structure, which is different from Example A1 only in that the hard core is directly covered by the conductive layer without including the soft layer.

[0209] The preparation method of the PC conductive composite material in this embodiment differs from that in Example A1 only in that step S2 is not included, and the hard core prepared in step S1 is directly subjected to step S3, and the object of the amination treatment in step S3 is changed to the hard core, and finally conductive particles are obtained.

[0210] Comparative Example A2

[0211] This comparative example provides a conductive particle and a preparation method thereof.

[0212] The structure of the conductive particles is a core-shell structure, which is different from Example A1 only in that the hard core is not included and the soft core is directly covered by the conductive layer.

[0213] The preparation method of the PC conductive composite material in this embodiment differs from that in Example A1 only in that: Step S1 and Step S2 are not included, and PET particles with the same particle size as the hard core body in Example A1 are directly provided as soft core bodies for Step S3, and the object of the amination treatment in Step S3 is changed to the soft core body, and finally conductive particles are obtained.

[0214] 2. PC conductive composite material and preparation method:

[0215] Example B1

[0216] This embodiment provides a PC conductive composite material and a preparation method.

[0217] The PC conductive composite material comprises the following components in parts by weight:

[0218] PC resin: 82 parts;

[0219] Conductive particles: 11 parts;

[0220] ABS resin: 7 parts;

[0221] Inorganic filler: 3 parts;

[0222] Lubricant: 0.5 parts;

[0223] Antioxidant: 0.3 parts;

[0224] The conductive particles are those provided in Example A1, the inorganic filler is a compound of barium sulfate and talc, the lubricant is calcium stearate, and the antioxidant is 1010.

[0225] The preparation method of the PC conductive composite material in this embodiment includes the following steps:

[0226] S4. First weigh the conductive particles and pour them into the high-speed mixer, then pour the weighed lubricant and antioxidant into the mixer, process at a speed of 200r / min for 4 minutes, and stir and mix evenly to obtain the first premix. Then pour the inorganic filler into the high-speed mixer and stir at high speed, and process at a speed of 200r / min for 12 minutes; then weigh a certain amount of PC resin and the first premix and pour them into the high-speed mixer at a speed of 200r / min for 12 minutes, and stir and mix evenly to obtain the second premix. Put the second premix into the feed port of the main feed of the twin-screw extruder, and then the materials are melt-mixed through the twin-screw extruder, the extrusion temperature is 280℃, and the main engine speed is 450rpm. The melt obtained by melt mixing is pulled out through a shaping die at a constant moving speed, and then cooled in a water tank to obtain a PC conductive composite material. Finally, it can be granulated by air drying and pelletizing to obtain particles with a particle size of 3mm for standby use.

[0227] Example B2

[0228] This embodiment provides a PC conductive composite material and a preparation method.

[0229] The PC conductive composite material comprises the following components in parts by weight:

[0230] PC resin: 95 parts;

[0231] Conductive particles: 19 parts;

[0232] ABS resin: 8 parts;

[0233] Inorganic filler: 4 parts;

[0234] Lubricant: 1 part;

[0235] Antioxidant: 0.7 parts;

[0236] The conductive particles are those provided in Example A1, the inorganic filler is a compound of barium sulfate and talc, the lubricant is calcium stearate, and the antioxidant is 1010.

[0237] The preparation method of the PC conductive composite material in this embodiment is different from that in embodiment B1 only in that the weight parts in step S4 are adjusted accordingly.

[0238] Example B3

[0239] This embodiment provides a PC conductive composite material and a preparation method.

[0240] The PC conductive composite material comprises the following components in parts by weight:

[0241] PC resin: 90 parts;

[0242] Conductive particles: 16 parts;

[0243] ABS resin: 10 parts;

[0244] Inorganic filler: 5 parts;

[0245] Lubricant: 0.8 parts;

[0246] Antioxidant: 1 part;

[0247] The conductive particles are those provided in Example A1, the inorganic filler is a compound of barium sulfate and talc, the lubricant is calcium stearate, and the antioxidant is 1010.

[0248] The preparation method of the PC conductive composite material in this embodiment is different from that in embodiment B1 only in that the weight parts in step S4 are adjusted accordingly.

[0249] Example B4

[0250] This embodiment provides a PC conductive composite material and a preparation method.

[0251] The only difference between the PC conductive composite material of this embodiment and that of embodiment B3 is that the conductive particles are the conductive particles provided in embodiment A2.

[0252] The preparation method of the PC conductive composite material in this embodiment differs from that in embodiment B3 only in that the conductive particles in step S4 are adjusted accordingly.

[0253] Example B5

[0254] This embodiment provides a PC conductive composite material and a preparation method.

[0255] The only difference between the PC conductive composite material of this embodiment and that of embodiment B3 is that the conductive particles are the conductive particles provided in embodiment A3.

[0256] The preparation method of the PC conductive composite material in this embodiment differs from that in embodiment B3 only in that the conductive particles in step S4 are adjusted accordingly.

[0257] Example B6

[0258] This embodiment provides a PC conductive composite material and a preparation method.

[0259] The only difference between the PC conductive composite material of this embodiment and that of embodiment B3 is that the conductive particles are the conductive particles provided in embodiment A4.

[0260] The preparation method of the PC conductive composite material in this embodiment differs from that in embodiment B3 only in that the conductive particles in step S4 are adjusted accordingly.

[0261] Comparative Example B1

[0262] This comparative example provides a PC conductive composite material and a preparation method.

[0263] The only difference between the PC conductive composite material of this comparative example and Example B3 is that the conductive particles are the conductive particles provided in Comparative Example A1.

[0264] The preparation method of the PC conductive composite material in this comparative example differs from that in Example B3 only in that the conductive particles in step S4 are adjusted accordingly.

[0265] Comparative Example B2

[0266] This comparative example provides a PC conductive composite material and a preparation method.

[0267] The only difference between the PC conductive composite material of this comparative example and Example B3 is that the conductive particles are the conductive particles provided in Comparative Example A2.

[0268] The preparation method of the PC conductive composite material in this comparative example differs from that in Example B3 only in that the conductive particles in step S4 are adjusted accordingly.

[0269] Comparative Example B3

[0270] This comparative example provides a PC conductive composite material and a preparation method.

[0271] The only difference between the PC conductive composite material in this comparative example and Example B3 is that 16 parts of conductive particles are replaced by 16 parts of carbon nanotubes.

[0272] The preparation method of the PC conductive composite material in this comparative example differs from that in Example B3 only in that 16 parts of conductive particles in step S4 are replaced by 16 parts of carbon nanotubes.

[0273] Comparative Example B4

[0274] This comparative example provides a PC conductive composite material and a preparation method.

[0275] The only difference between the PC conductive composite material in this comparative example and Example B3 is that the 16 parts of conductive particles are replaced by 12 parts of SiO2@PTFE@PET (without conductive layer) prepared in step S2 of Example A1, and 4 parts of carbon nanotubes are added, and step S3 is omitted.

[0276] The preparation method of the PC conductive composite material in this comparative example differs from that in Example B3 only in that the 16 parts of conductive particles in step S4 are replaced with 12 parts of SiO2@PTFE@PET (without conductive layer) prepared in step S2 of Example A1, and 4 parts of carbon nanotubes are added.

[0277] Comparative Example B5

[0278] This comparative example provides a PC conductive composite material and a preparation method.

[0279] The only difference between the PC conductive composite material in this comparative example and Example B3 is that the 16 parts of conductive particles are replaced by 12 parts of SiO2@PTFE (without soft layer and conductive layer) obtained in step S1 of Example A1, and 4 parts of carbon nanotubes are added, and there is no step S3.

[0280] The preparation method of the PC conductive composite material in this comparative example differs from that in Example B3 only in that the 16 parts of conductive particles in step S4 are replaced with 12 parts of SiO2@PTFE (without soft layer and conductive layer) prepared in step S2 of Example A1, and 4 parts of carbon nanotubes are added.

[0281] The compositions of the PC conductive composite materials provided in Examples B1 to B6 and Comparative Examples B1 to B5 are shown in Table 1:

[0282] Table 1

[0283] Related characteristics test

[0284] The prepared PC conductive composite material samples were injection molded into test strips according to standard dimensions and then fabricated into carrier tapes. Physical properties were tested according to ASTM standards. Surface resistivity was tested using the DC comparison method. The test equipment and measurement error complied with GB / T 3048.5. The test results are shown in Table 2.

[0285] Table 2

[0286] As can be seen from Table 1, compared with Comparative Examples B1 to B5, Examples B1 to B6 of the present application prepare a hard core-soft layer-conductive layer of a core-shell structure as conductive particles, prepare PC conductive composite materials with PC resin and other materials, and then prepare plastic leather materials, and their conductivity, conductive uniformity, surface smoothness, and toughness performance are significantly improved.

[0287] It can be seen from Example B3 and Example B6 that by further preparing a hard core body with a hard inner core and a flame retardant layer, conductive particles with a richer layer structure can be finally prepared. Compared with directly coating the hard core body with a soft layer, in addition to improving the flame retardant effect, it can further improve the conductivity, conductive uniformity, surface smoothness and toughness when applied to plastic leather materials.

[0288] It can be seen from Examples B3, B4, and B5 that the toughening effect of the core-shell structured conductive particles on plastic leather can be improved by further selecting the particle size of the hard core or controlling the mass ratio of the hard core to the soft layer.

[0289] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present application should be included in the scope of protection of the present application.

Claims

1. A conductive particle, characterized in that: It comprises a hard core, a soft layer and a conductive layer, wherein the soft layer covers the hard core, the conductive layer covers the surface of the soft layer away from the hard core, and the conductive layer comprises carbon nanotubes, which are dispersed in the conductive layer.

2. The conductive particles according to claim 1, characterized in that The hard core body includes at least one of the following (1) to (3): (1) Particle size D50 is 0.1 to 3 μm; (2) The material of the hard core body includes at least one of silicon dioxide, calcium carbonate, aluminum oxide, and magnesium oxide; (3) The hard core body includes a hard inner core and a flame retardant layer, and the flame retardant layer covers the hard inner core.

3. The conductive particles according to claim 2, characterized in that The hard core or the flame retardant layer includes at least one of the following (1) to (6): (1) The surface of the hard inner core is porous, and the flame retardant layer is partially embedded in the pores on the surface of the hard inner core; (2) The particle size D50 of the hard inner core is 0.1 to 2 μm; (3) The particle size D100 of the hard inner core is 1 to 4 μm; (4) The hard material of the hard inner core includes at least one of mesoporous silica, porous alumina, and porous magnesia; (5) The thickness of the flame retardant layer is 0.1 to 1 μm; (6) The flame retardant material of the flame retardant layer includes at least one of PTFE, FEP, PCTFE, and PVDF.

4. The conductive particles according to any one of claims 1 to 3, characterized in that: The soft layer includes at least one of the following (1) to (3): (1) The mass ratio of the hard core to the soft layer is 2 to 5:1; (2) The thickness of the soft layer is 0.1 to 1 μm; (3) The soft material of the soft layer includes at least one of PET, silicone rubber, and styrene-butadiene rubber.

5. The conductive particle according to any one of claims 1 to 4, characterized in that: The conductive layer or the carbon nanotube includes at least one of the following (1) to (9): (1) The thickness of the conductive layer is 0.1 to 1 μm; (2) The mass ratio of the carbon nanotubes to the conductive layer is 50% to 100%; (3) the carbon nanotubes are grafted onto the surface of the soft layer away from the hard core; (4) The aspect ratio of the carbon nanotubes is 5000 to 10000:1; (5) The inner diameter of the carbon nanotube is 1 to 2 nm; (6) The outer diameter of the carbon nanotube is 8 to 25 nm; (7) The length of the carbon nanotubes is 1 to 100 μm; (8) The specific surface area of ​​the carbon nanotubes is 200 to 400 m 2 / g; (9) The ash content of the carbon nanotubes is ≤ 2%.

6. The conductive particle according to any one of claims 1 to 5, characterized in that: The conductive particles include at least one of the following (1) and (2): (1) The particle size D90 of the conductive particles is 1 to 6 μm; (2) The conductive particles have a powder resistivity of 70 to 90 mΩ·cm.

7. A method for preparing conductive particles, characterized in that: The steps include: Performing a first coating treatment on the surface of the hard core body with a slurry including a soft material to form a soft layer; A second coating treatment is performed on the surface of the soft layer away from the hard core body, including a conductive material, to form a conductive layer to obtain conductive particles; wherein the conductive material includes carbon nanotubes.

8. The preparation method according to claim 7, characterized in that: The preparation method of the hard core body comprises the following steps: Performing a third coating treatment on the surface of the hard inner core with a slurry including a flame retardant material to form a flame retardant layer to obtain the hard inner core; and / or The first coating process comprises the following steps: preparing a slurry of the soft material including the soft material, a solvent and a first surfactant; After the slurry of the soft material is solidified on the surface of the hard core body, the soft layer is formed on the surface of the hard core body; and / or The second coating process comprises the following steps: The carbon nanotubes are carboxylated, and the surface of the soft layer away from the hard core is aminoated. The carboxyl group and the amino group undergo an amidation reaction through a coupling agent, so that the carbon nanotubes are grafted onto the surface of the soft layer.

9. The preparation method according to claim 8, characterized in that: The third coating process comprises the following steps: The flame retardant material, glacial acetic acid and solvent are prepared into a slurry of the flame retardant material, and the mixture is prepared with the hard core to form a mixture slurry, and the pH value of the mixture slurry is made to be 5-7, and the hard core body is obtained after reaction; and / or In the third coating process, the mass ratio of the hard core to the flame retardant material is 5 to 10:1; and / or The first surfactant includes at least one of sodium lauryl sulfate, alkyl glucoside, and fatty acid glyceride; and / or The carboxylation treatment comprises the following steps: Carboxylating the carbon nanotubes by sulfuric acid and hydrochloric acid; and / or The amination treatment comprises the following steps: Performing an amination reaction on the soft layer by using an aminating agent, wherein the aminating agent includes at least one of N-β-(aminoethyl)-γ-aminopropyltrimethoxysilane and 3-aminopropyltriethoxysilane; and / or The coupling agent includes at least one of diisopropylcarbodiimide, 1-hydroxybenzotriazole, and dimethylaminoethanol.

10. A PC conductive composite material, characterized in that: The invention comprises PC resin and also comprises the conductive particles according to any one of claims 1 to 6 or the conductive particles prepared by the preparation method according to any one of claims 7 to 9.

11. The PC conductive composite material according to claim 10, characterized in that: The composition comprises the following components in parts by weight: The PC resin: 80-95 parts; The conductive particles: 10 to 20 parts; Auxiliary resin: 5-10 parts; Inorganic filler: 1 to 5 parts; Lubricant: 0.1-1 part; Antioxidant: 0.1-1 part; Compatibilizer: 0-2 parts; Second surfactant: 0 to 2 parts.

12. The PC conductive composite material according to any one of claims 10 or 11, characterized in that: The PC resin includes at least one of the following (1) and (2): (1) Weight average molecular weight is 30,000 to 50,000 g / mol; (2) The melt index at 300°C and 1.2 kg is 15 g / 10 min to 25 g / 10 min.

13. The PC conductive composite material according to claim 11 or 12, characterized in that: The auxiliary resin includes at least one of ABS resin and SBS resin; and / or The inorganic filler includes calcium carbonate, barium sulfate, talcum powder, boron nitride powder, silicon dioxide, alum, titanium dioxide, At least one of calcium oxide, magnesium oxide, carbon black, and mica powder; and / or The inorganic filler comprises barium sulfate and talc; and / or The lubricant comprises at least one of calcium stearate, talc and polyethylene wax; and / or The antioxidant includes at least one of 1010, 168, 1076, 1330, 1035, 3144, 1024, 126; and / or The compatibilizer comprises maleic anhydride grafted methyl methacrylate; and / or The second surfactant includes at least one of sodium dodecyl sulfate, sodium dodecyl sulfonate, sodium dodecylbenzene sulfonate, sodium tetradecyl sulfate, sodium tetradecyl sulfonate, and sodium tetradecylbenzene sulfonate.

14. A method for preparing a PC conductive composite material, characterized in that: The steps include: The components of the PC conductive composite material according to any one of claims 10 to 13 are mixed to obtain a PC conductive composite material.

15. The preparation method according to claim 14, characterized in that: The mixing process comprises the following steps: The PC resin and the conductive particles are pretreated separately and then mixed together to obtain the PC conductive composite material.

16. The preparation method according to claim 15, characterized in that: The mixing process is carried out by a twin-screw extruder at a temperature of 260 to 300°C.

17. The preparation method according to any one of claims 14 to 16, characterized in that: The following steps are also included: The obtained PC conductive composite material is granulated to obtain particles with a particle size of 2 to 3 mm.

18. A plastic leather material, characterized in that: It comprises a base layer and an antistatic layer laminated with the base layer, wherein the material of the antistatic layer comprises the PC conductive composite material described in any one of claims 10 to 13, or comprises the PC conductive composite material prepared by the preparation method described in any one of claims 14 to 17.

19. The plastic leather material according to claim 18, characterized in that: The thickness of the antistatic layer is 0.1 to 0.4 mm; and / or The thickness of the base layer is 1 to 1.6 mm.

Images