Composite nano-conductive particle for high-voltage semi-conductive shielding material and preparation method of semi-conductive shielding material

Abstract

This invention relates to a composite nano-conductive particle for high-voltage semiconductor shielding materials and a method for preparing the semiconductor shielding material. The composite nano-conductive particle comprises: a resin matrix, a polyhydroxyalkanoate carbon black composite nano-conductive filler, and optional processing aids. The composite nano-conductive particle of this invention improves the compatibility between carbon black and the resin matrix, effectively disperses carbon black in the resin matrix, significantly improves the voltage withstand rating of the semiconductor shielding material, noticeably enhances the dispersion effect of carbon black in the resin, reduces the amount of carbon black added in the production of high-voltage shielding materials, and greatly improves production efficiency.

Description

Technical Field

[0001] This invention belongs to the field of polymer composite materials and relates to a composite nano-conductive particles for use in high-voltage semiconductor shielding materials and a method for preparing semiconductor shielding materials. Background Technology

[0002] Semiconducting shielding materials are semiconducting materials with shielding effects, widely used in the cable industry. However, the dispersion requirements of carbon black in the system are extremely stringent. Due to its large specific surface area, carbon black exhibits severe agglomeration when added to the matrix resin, and its interaction with the matrix is ​​weak, resulting in poor dispersion. High proportions of carbon black are extremely difficult to disperse in the matrix resin system, easily agglomerating and causing severe surface protrusions and reduced smoothness. Therefore, improving the dispersibility of carbon black in the polymer matrix, while ensuring conductivity, is crucial to reducing the impact of carbon black addition on the viscosity of the matrix prepolymer. In existing semiconducting shielding material production processes, carbon black is used in powder form, directly added to the extruder. This carbon black processing and dispersion process has significant shortcomings.

[0003] Chinese patents CN103739929A, CN104356487A, CN101942142A, CN106883505A, and CN110079004A improve the dispersibility of carbon black by simply adding carbon black, highly conductive carbon black, or additional dispersants. However, the addition of compatibilizers disrupts the secondary structure of carbon black within the material, leading to a decrease in the uniformity of the conductive secondary structure of carbon black, which in turn reduces the uniformity of the material. Furthermore, the testing of protrusions in the semiconductor shielding material after the addition of new substances is also a challenge. Summary of the Invention

[0004] To address the aforementioned problems, this invention provides composite nano-conductive particles for high-voltage semiconductor shielding materials. By modifying the surface of carbon black with polyhydroxyalkanoates, a carbon black-polyhydroxyalkanoates-resin interface is constructed, significantly improving the dispersibility of carbon black and thus enhancing the interfacial bonding between carbon black and resin. This approach balances mechanical and electrical properties, thereby solving the bottleneck problem in the production and application of carbon black in shielding materials. Because this invention directly improves the functional group structure of the carbon black interface, it greatly enhances the dispersion effect of carbon black in the resin system without reducing the conductivity of the material or the smoothness of the shielding layer.

[0005] To achieve the above-mentioned objectives, the technical solution adopted by this invention is as follows:

[0006] A composite nano-conductive particle for use as a shielding material in high-voltage semiconductors, comprising the following components:

[0007] 10-80 parts by weight of resin matrix;

[0008] 20-90 parts by weight of polyhydroxyalkanoate carbon black composite nano-conductive filler;

[0009] 0-3 parts by weight of processing aid.

[0010] As a preferred embodiment, the resin matrix comprises one or more of ethylene-vinyl acetate copolymer, polyvinyl acetate, ethylene-butyl acrylate copolymer, and ethylene-acrylic acid copolymer.

[0011] As a preferred embodiment, the preparation method of the polyhydroxyalkanoate carbon black composite nano-conductive filler includes the following steps:

[0012] (1) Carbon black is dissolved in chloroform and mixed to form a carbon black dispersion solution, thus preparing carbon black dispersion-1;

[0013] (2) Add polyhydroxy fatty acid ester to carbon black dispersion-1, mix, and after solid-liquid separation and post-treatment, obtain polyhydroxy fatty acid ester carbon black composite nano conductive filler.

[0014] As a preferred embodiment, the carbon black is contact carbon black, furnace carbon black, or pyrolysis carbon black. Preferably, the carbon black is pyrolysis carbon black, and more preferably, the carbon black is acetylene black. Acetylene black is produced by the thermal decomposition of acetylene gas as a raw material. Acetylene black has a well-developed branched structure, good electrical conductivity, and is suitable for manufacturing conductive products.

[0015] As a preferred embodiment, the polyhydroxy fatty acid ester comprises one or more of poly-β-hydroxybutyrate, poly(3-hydroxybutyrate-co-3-hydroxyvalerate), poly(3-hydroxybutyrate-co-3-hydroxyhexanoate), poly(3-hydroxybutyrate-co-4-hydroxybutyrate), and poly(3-hydroxypropionic acid), with a number average molecular weight of 50,000 to 80,000 and an ester group content of 5 wt% to 20 wt%; preferably, the polyhydroxy fatty acid ester is poly-β-hydroxybutyrate, with a number average molecular weight of 63,000 to 70,000 and an ester group content of 10 wt% to 15 wt%.

[0016] As a preferred embodiment, in step (1), the carbon black dispersion solution-1 contains 1%-50% carbon black by mass, preferably 1%-15%.

[0017] As a preferred option, the mixing time for preparing the carbon black dispersion solution-1 in step (1) is 0.5-4 hours.

[0018] As a preferred embodiment, the stirring speed during the preparation of the carbon black dispersion solution-1 in step (1) is 600RPM-2000RPM.

[0019] As a preferred embodiment, in step (2), the polyhydroxyalkanoate accounts for 1%-60% of the carbon black mass, preferably 5%-40%.

[0020] As a preferred embodiment, in step (2), the mixing time is 0.5-4 hours and the mixing temperature is 55-90℃.

[0021] As a preferred embodiment, in step (2), the stirring speed during mixing is 600RPM-2000RPM.

[0022] As a preferred embodiment, in step (2), the post-processing includes the following steps: centrifugal washing followed by drying at a temperature of 40-100℃.

[0023] Furthermore, as a preferred embodiment, the preparation method of the composite conductive nanoparticles includes the following steps: according to a certain proportion,

[0024] (a) The resin matrix, polyhydroxy fatty acid ester carbon black composite nano-conductive filler and optional processing aids are dispersed in an organic solvent to obtain a resin matrix dispersion and a polyhydroxy fatty acid ester carbon black composite nano-conductive filler dispersion.

[0025] (b) Mix and disperse the two dispersions obtained in step (a) evenly, cool to room temperature to precipitate, and then perform post-treatment.

[0026] As a preferred embodiment, in the preparation method of the composite conductive nanoparticles, the organic solvent is selected from one or more of toluene, xylene, tetrahydrofuran, and acetone; xylene is preferred.

[0027] As a preferred embodiment, the post-processing of the method for preparing the composite conductive nanoparticles includes the following steps: washing with deionized water, filtering, and drying.

[0028] As a preferred embodiment, in the preparation method of the composite conductive nanoparticles, the mixing and dispersion time in step (b) is 2-4 hours.

[0029] This invention also provides a method for preparing a semiconductor shielding material, comprising the following steps: according to a ratio,

[0030] (1) Premixing: Add the polymer, composite nano-conductive particles and optional processing aids to a mixer and stir to obtain a premix;

[0031] (2) Extrusion: The obtained premix is ​​granulated using a twin-screw extruder;

[0032] (3) Post-absorption: Add DCP at 0.13% to 0.25 wt% of the raw material mass in step (1), shake well, let stand and absorb for 1 to 2 hours to obtain the semiconductor shielding material.

[0033] As a preferred embodiment, the polymer comprises one or more of ethylene-vinyl acetate copolymer, polyvinyl acetate, ethylene-butyl acrylate copolymer, and ethylene-acrylic acid copolymer.

[0034] As a preferred embodiment, the mass ratio of the polymer to the composite conductive nanoparticles is 0–90:10–100.

[0035] As a preferred option, in step (1), the premixing mixer uses a high-speed mixer with a speed of 1000-1500 RPM and a premixing time of 5 min.

[0036] As a preferred option, in step (2), the extruder processing temperature is 160-200℃, the screw speed is controlled at 200-600rpm, and the vacuum degree of the vacuum device is between -0.9 bar and -0.5 bar.

[0037] The processing aids described in this invention are selected from one or more of antioxidants, lubricants, ultraviolet absorbers, heat stabilizers, and flow modifiers.

[0038] As a preferred embodiment, the antioxidant is one or more of phosphites, thioesters, and acryloyl-modified phenols. Preferably, one or more of the following BASF antioxidants are used: Irganox 1076, Irganox 1010, Irganox 168, Irgafos 126, Irgafos P-EPQ, and Irganox B900.

[0039] As a preferred embodiment, the lubricant is one or more of the following: fatty alcohols, metallic soaps, ester lubricants, organosilicon and silicone powders, and organofluorine compounds. Ester lubricants, such as PETS from Lonza, are preferred.

[0040] As a preferred embodiment, the ultraviolet absorber is one or more of benzotriazoles and triazines. Preferably, Tinuvin 234, Tinuvin 360, Tinuvin 1577, etc., from BASF are used.

[0041] The principle of preparing composite conductive nanoparticles in this invention is explained as follows: Polyhydroxyalkanoates (PHA) are pure natural and non-toxic substances. Due to their abundant hydroxyl groups, PHAs also possess some special chemical properties, such as reacting with free radicals, undergoing chelation reactions, and forming hydrogen bonds. PHAs can be adsorbed onto fillers containing benzene ring structures through hydrogen bonds or π-π adsorption between benzene rings. Simultaneously, PHAs can be oxidized to ortho-quinone structures. These ortho-quinone structures can undergo covalent reactions with polar groups in the polymer under high-temperature conditions, resulting in a certain degree of cross-linking. The content of highly polar ester groups has a significant impact on the formation of these quinone structures. A higher ester group content leads to more quinone structures, resulting in higher material hardness and extrusion failure at the customer's cable extrusion point. Conversely, a lower ester group content prevents effective interfacial bonding with the polar groups on the carbon black surface.

[0042] Carbon black possesses the ability to capture free radicals. Its condensed benzene rings contain quinone oxygen groups and unsaturated hydrogen atoms, which free radicals can attack the double bonds at these positions, thus bonding to the carbon black surface. The carbon black oil absorption value (DBP value) is an important indicator of the degree of carbon black aggregation. Under specified test conditions, the DBP value, representing the volume of dibutyl phthalate (DBP) absorbed by 100g of carbon black, can be used to calculate the void volume between carbon black aggregates. Therefore, it is a measure of the degree of carbon black aggregation and agglomeration, reflecting the specific surface area of ​​the carbon black. A larger specific surface area indicates more quinone oxygen groups and unsaturated hydrogen atoms on the surface, resulting in stronger interactions with the polar groups of polyhydroxyalkanoates. However, a larger specific surface area also indicates poorer flowability, which is detrimental to processing.

[0043] The core idea of ​​this invention is that the phenolic hydroxyl groups in polyhydroxyalkanoates can lose hydrogen to generate two free radicals, which can then be captured by carbon black and bonded to the carbon black surface. Based on this mechanism, one end of the polyhydroxyalkanoate can adsorb carbon black, while the other end chemically binds to the resin matrix molecular chain, thereby constructing a carbon black-polyhydroxyalkanoate-resin matrix interface, as shown below:

[0044]

[0045] The beneficial effects of this invention are as follows:

[0046] (1) The present invention first prepared a polyhydroxyalkanoate / carbon black composite nano-conductive filler. The introduction of polyhydroxyalkanoate greatly improved the interfacial interaction between carbon black and resin matrix, making carbon black easier to disperse. The material performance is reflected in the significant decrease in electrical conductivity of the material under low carbon black filling. For the above reasons, the present invention achieves a significant reduction in the amount of carbon black added while ensuring that the electrical conductivity meets the requirements of high voltage shielding material. It achieves mechanical and electrical properties that meet the performance requirements of high voltage shielding material under the condition of low carbon black addition. The low amount of carbon black added and good dispersibility also make the shielding layer surface smoother, greatly reduce protrusions, and greatly broaden the production process window of shielding material.

[0047] (2) The electrostatic forces between the branches of carbon black are very large, making it easy to agglomerate, which makes it very difficult to disperse during processing. The introduction of polyhydroxy fatty acid esters improves the surface compatibility of carbon black, increases the spatial distance between carbon black molecules and between aggregates, reduces the interaction force between carbon black particles, reduces the tendency of carbon black to agglomerate, and reduces the difficulty of carbon black dispersion in downstream processing. Detailed Implementation

[0048] To better understand and implement the invention, the present invention will be further described below with reference to the embodiments. However, the present invention is not limited to the listed embodiments, but should also include any other known modifications within the scope of the claims of the present invention.

[0049] Performance tests are as follows:

[0050] Sample preparation: The particle molding method shall be adopted, and the procedure shall be performed in accordance with the provisions of 6.2.1 in JB / T 10738-2007. The test pieces shall be flat, smooth, uniform in thickness, and free of air bubbles. The thickness of the test pieces shall meet the requirements of each test item.

[0051] Tensile strength and elongation at break: shall be performed in accordance with GB / T 1040.1 and GB / T 1040.2. The specimen shall be a 5A type specimen with a thickness of 1.0±0.1 mm and a tensile speed of 200±20 mm / min.

[0052] Heat extension test: It shall be performed in accordance with GB / T 2951.5, and the sample preparation shall be performed in accordance with GB / T 1040.2.

[0053] Volume resistivity: The volume resistivity at 23℃ shall be determined in accordance with GB / T 3048.3. The sample shall be acclimatized in an environment with a temperature of 23±3℃ and a relative humidity of 50±5% for no less than 24 hours.

[0054] Surface protrusions: Comply with Appendix A of Q / GDW 11883.2—2018; the resolution of protrusion height by the detector should be better than 25 μm. Sampling and testing standards: Class 1000 cleanroom.

[0055] The components of the comparative examples and embodiments are as follows:

[0056] Ethylene-vinyl acetate copolymer: Dow Chemical, grade 40W, melt index 10.5 ± 0.5 under ASTM D-1238 test conditions.

[0057] Polyhydroxy fatty acid ester: poly-β-hydroxybutyrate, CAS: 26744-04-7, Shanghai Yuanye Biotechnology Co., Ltd., purity 98%, number average molecular weight 68000, ester group content 12%~14%.

[0058] Ethanol: Tianjin Xinbote, laboratory grade, analytical grade.

[0059] Carbon tetrachloride: Produced by Hsiung-Ta Chemical Co., Ltd., laboratory grade, analytical grade, density 1.595 g / cm³ at 20°C. 3 .

[0060] Carbon black: Produced by Cabot, grade VULCAN XC500, nano-conductive grade, oil absorption value 120.

[0061] DCP: Dicumyl peroxide, manufactured by AkzoNobel, analytical grade, grade UN-3106.

[0062] Antioxidant: Irganox B900, manufactured by BASF.

[0063] Lubricant: PETS, pentaerythritol stearate, manufactured by Lonza Corporation, USA.

[0064] Carbon black dispersion-1:

[0065] Step 1: Add 1 kg of carbon black to chloroform in batches, start stirring, set the speed to 800 RPM, and stir at room temperature for 1 hour; prepare a 5% carbon black chloroform solution to obtain carbon black dispersion-1.

[0066] Polyhydroxyalkanoate carbon black composite nano-conductive filler:

[0067] Step 1: Add 100g of polyhydroxyalkanoate to carbon black dispersion-1 and ultrasonically disperse for 0.5 hours;

[0068] Step 2: Transfer the mixed solution of polyhydroxy fatty acid ester and carbon black from step 1 to a stirrer, set the temperature to 80℃ and stir for 2 hours to complete the reaction, with a stirring speed of 1500 RPM.

[0069] Step 3: After the reaction is complete, the temperature is raised to remove chloroform, and the solid after solid-liquid separation is dried in an oven at 80°C to obtain polyhydroxyalkanoate carbon black composite nano-conductive filler.

[0070] Preparation of composite conductive nanoparticles:

[0071] Step 1: Dissolve 10 parts by weight of ethylene-vinyl acetate copolymer in 90 parts by weight of carbon tetrachloride at 165°C; add 10 parts by weight of polyhydroxyalkanoate carbon black conductive filler to 90 parts by weight of carbon tetrachloride and sonicate at room temperature for 2 hours to disperse it evenly.

[0072] Step 2: Slowly pour the mixture of polyhydroxyalkanoate carbon black composite conductive filler and carbon tetrachloride into the carbon tetrachloride solution of ethylene-vinyl acetate copolymer, and continue stirring for 4 hours; precipitate is formed, and after washing with deionized water, filtering, drying, crushing and grinding, composite nano-conductive particles with a carbon black mass content of 45% are obtained.

[0073] Example 1

[0074] Step 1: Add 8 kg of ethylene-vinyl acetate copolymer, 2 kg of composite nano-conductive particles, 30 g of antioxidant, and 30 g of lubricant to a high-speed mixer;

[0075] Step 2: Start the high-speed mixer at 1200 RPM and stir for 5 minutes to prepare premix A;

[0076] Step 3: Set the extruder processing temperature to 180℃ and control the screw speed to 350 rpm; control the reciprocating machine capacity to 10 kg / H; set the vacuum level of the devolatilization system vacuum device to between -0.9 bar and -0.5 bar;

[0077] Step 4: Feed premix A into a reciprocating extruder for granulation;

[0078] Step 5: Mix 10kg of granulated particles with 20g of DCP by hand and let stand for 2 hours;

[0079] Step 6: After the particles have been left to stand in step 5, test them according to the test standard requirements.

[0080] Example 2

[0081] Step 1: Add 6 kg of ethylene-vinyl acetate copolymer, 4 kg of composite nano-conductive particles, 30 g of antioxidant, and 30 g of lubricant to a high-speed mixer;

[0082] Step 2: Start the high-speed mixer at 1200 RPM and stir for 5 minutes to prepare premix B;

[0083] Step 3: Set the extruder processing temperature to 180℃ and control the screw speed to 350 rpm; control the reciprocating machine capacity to 10 kg / H; set the vacuum level of the devolatilization system vacuum device to between -0.9 bar and -0.5 bar;

[0084] Step 4: Feed premix B into a reciprocating extruder for granulation;

[0085] Step 5: Mix 10 kg of granulated particles with 20 g of DCP by hand and let stand for 2 hours.

[0086] Step 6: After the particles have been left to stand in step 5, test them according to the test standard requirements.

[0087] Example 3

[0088] Step 1: Add 4 kg of ethylene-vinyl acetate copolymer, 6 kg of composite nano-conductive particles, 30 g of antioxidant, and 30 g of lubricant to a high-speed mixer;

[0089] Step 2: Start the high-speed mixer at 1200 RPM and stir for 5 minutes to prepare premix C;

[0090] Step 3: Set the extruder processing temperature to 180℃ and control the screw speed to 350 rpm; control the reciprocating machine capacity to 10 kg / H; set the vacuum level of the devolatilization system vacuum device to between -0.9 bar and -0.5 bar;

[0091] Step 4: Feed the premix C into a reciprocating extruder for granulation;

[0092] Step 5: Mix 10 kg of granulated particles with 20 g of DCP by hand and let stand for 2 hours.

[0093] Step 6: After the particles have been left to stand in step 5, test them according to the test standard requirements.

[0094] Example 4

[0095] Step 1: Add 2 kg of ethylene-vinyl acetate copolymer, 8 kg of composite nano-conductive particles, 30 g of antioxidant, and 30 g of lubricant to a high-speed mixer;

[0096] Step 2: Start the high-speed mixer at 1200 RPM and stir for 5 minutes to prepare premix D;

[0097] Step 3: Set the extruder processing temperature to 180℃ and control the screw speed to 350 rpm; control the reciprocating machine capacity to 10 kg / H; set the vacuum level of the devolatilization system vacuum device to between -0.9 bar and -0.5 bar;

[0098] Step 4: Feed the premix D into a reciprocating extruder for granulation;

[0099] Step 5: Mix 10 kg of granulated particles with 20 g of DCP by hand and let stand for 2 hours.

[0100] Step 6: After the particles have been left to stand in step 5, test them according to the test standard requirements.

[0101] Example 5

[0102] Step 1: Add 10kg of composite nano-conductive particles, 30g of antioxidant, and 30g of lubricant to a high-speed mixer;

[0103] Step 2: Start the high-speed mixer at 1200 RPM and stir for 5 minutes to prepare premix E;

[0104] Step 3: Set the extruder processing temperature to 180℃ and control the screw speed to 350 rpm; control the reciprocating machine capacity to 10 kg / H; set the vacuum level of the devolatilization system vacuum device to between -0.9 bar and -0.5 bar;

[0105] Step 4: Feed the premix E into a reciprocating extruder for processing and granulation;

[0106] Step 5: Mix 10 kg of granulated particles with 20 g of DCP by hand and let stand for 2 hours.

[0107] Step 6: After the particles have been left to stand in step 5, test them according to the test standard requirements.

[0108] Comparative Example 1

[0109] Step 1: Add 8.94 kg of ethylene-vinyl acetate copolymer, 30 g of antioxidant, and 30 g of lubricant to a high-speed mixer;

[0110] Step 2: Start the high-speed mixer at 1200 RPM and stir for 5 minutes to prepare a premix F containing all components except carbon black;

[0111] Step 3: Set the extruder processing temperature zone to 180℃ and control the screw speed to 350rpm; control the reciprocating machine capacity to 10kg / H.

[0112] Step 4: Feed the premix F into the reciprocating extruder, and at the same time feed 1.0 kg of carbon black powder into the reciprocating extruder for processing and granulation by side feeding.

[0113] Step 5: Mix 10 kg of granulated particles with 20 g of DCP by hand and let stand for 2 hours.

[0114] Step 6: After the particles have been left to stand in step 5, test them according to the test standard requirements.

[0115] Comparative Example 2

[0116] Step 1: Add 7.94 kg of ethylene-vinyl acetate copolymer, 30 g of antioxidant, and 30 g of lubricant to a high-speed mixer;

[0117] Step 2: Start the high-speed mixer at 1200 RPM and stir for 5 minutes to prepare a premix G containing all components except carbon black.

[0118] Step 3: Set the extruder processing temperature zone to 180℃ and control the screw speed to 350rpm; control the reciprocating machine capacity to 10kg / H.

[0119] Step 4: Feed the premix G into the reciprocating extruder, and at the same time feed 2kg of carbon black powder into the reciprocating extruder for processing and granulation by side feeding.

[0120] Step 5: Mix 10 kg of granulated particles with 20 g of DCP by hand and let stand for 2 hours.

[0121] Step 6: After the particles have been left to stand in step 5, test them according to the test standard requirements.

[0122] Comparative Example 3

[0123] Step 1: Add 6.94 kg of ethylene-vinyl acetate copolymer, 30 g of antioxidant, and 30 g of lubricant to a high-speed mixer;

[0124] Step 2: Start the high-speed mixer at 1200 RPM and stir for 5 minutes to prepare a premix of components other than carbon black, H.

[0125] Step 3: Set the extruder processing temperature zone to 180℃ and control the screw speed to 350rpm; control the reciprocating machine capacity to 10kg / H.

[0126] Step 4: Feed the premix H into the reciprocating extruder, and at the same time feed 3 kg of carbon black powder into the reciprocating extruder for processing and granulation by side feeding.

[0127] Step 5: Mix 10 kg of granulated particles with 20 g of DCP by hand and let stand for 2 hours.

[0128] Step 6: After the particles have been left to stand in step 5, test them according to the test standard requirements.

[0129] Comparative Example 4

[0130] Step 1: Add 5.94 kg of ethylene-vinyl acetate copolymer, 30 g of antioxidant, and 30 g of lubricant to a high-speed mixer;

[0131] Step 2: Start the high-speed mixer at 1200 RPM and stir for 5 minutes to prepare premix I of components other than carbon black;

[0132] Step 3: Set the extruder processing temperature zone to 180℃ and control the screw speed to 350rpm; control the reciprocating machine capacity to 10kg / H.

[0133] Step 4: Feed premix I into the reciprocating extruder, and at the same time feed 4 kg of carbon black powder into the reciprocating extruder for processing and granulation by side feeding.

[0134] Step 5: Mix 10 kg of granulated particles with 20 g of DCP by hand and let stand for 2 hours.

[0135] Step 6: After the particles have been left to stand in step 5, test them according to the test standard requirements.

[0136] Table 1 shows a comparison of the material properties of the examples and comparative examples:

[0137] Table 1. Material properties of examples and comparative examples

[0138]

[0139] Examples 1 and 2 show that effective dispersion of carbon black and a low conductivity level can be achieved at a low addition ratio (10%–20%). Comparison of Examples 2, 3, 4, and 5 with Comparative Examples 1, 2, 3, and 4 demonstrates that the use of composite nano-conductive particles significantly improves product performance, resulting in lower volume resistivity, fewer surface protrusions, and better mechanical properties. This proves that this addition method can significantly improve the dispersion effect of carbon black. Comparison of Examples 4 and 5 with Comparative Example 4 shows that adding carbon black using composite nano-conductive particles allows for a larger proportion of carbon black to be added, significantly improving production efficiency. Furthermore, when the carbon black proportion is high, there is no significant change in surface protrusions, further proving that the composite nano-conductive particle scheme of this invention can greatly improve the dispersion ability of carbon black in shielding materials.

[0140] As can be seen from the various embodiments and comparative examples, the preparation of composite conductive nanoparticles using the process route and formulation system of the present invention can greatly improve the dispersion effect of carbon black in polymer systems, improve product quality, and enable the products to meet the application requirements of high voltage levels; at the same time, this process route breaks through existing production bottlenecks and greatly improves production efficiency.

[0141] Those skilled in the art should understand that this invention is not limited to the above embodiments. Various changes and modifications can be made to this invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the invention as claimed. The scope of protection of this invention is defined by the appended claims.

Claims

1. A composite nano-conductive particle for use as a shielding material in high-voltage semiconductors, comprising the following components: 10-80 parts by weight of resin matrix; 20-90 parts by weight of polyhydroxyalkanoate carbon black composite nano-conductive filler; 0-3 parts by weight of processing aid.

2. The composite conductive nanoparticles according to claim 1, characterized in that, The resin matrix comprises one or more of ethylene-vinyl acetate copolymer, polyvinyl acetate, ethylene-butyl acrylate copolymer, and ethylene-acrylic acid copolymer.

3. The composite conductive nanoparticles according to claim 1 or 2, characterized in that, The preparation method of the polyhydroxyalkanoate carbon black composite nano-conductive filler includes the following steps: (1) Carbon black is dissolved in chloroform and mixed to form a carbon black dispersion solution, thus preparing carbon black dispersion-1; (2) Add polyhydroxy fatty acid ester to carbon black dispersion-1, mix, and after solid-liquid separation and post-treatment, obtain polyhydroxy fatty acid ester carbon black composite nano conductive filler.

4. The composite conductive nanoparticles according to any one of claims 1-3, characterized in that, The polyhydroxy fatty acid ester comprises one or more of poly-β-hydroxybutyrate, poly(3-hydroxybutyrate-co-3-hydroxyvalerate), poly(3-hydroxybutyrate-co-3-hydroxyhexanoate), poly(3-hydroxybutyrate-co-4-hydroxybutyrate), and poly(3-hydroxypropionic acid), with a number average molecular weight of 50,000 to 80,000 and an ester group content of 5 wt% to 20 wt%; preferably, the polyhydroxy fatty acid ester is poly-β-hydroxybutyrate, with a number average molecular weight of 63,000 to 70,000 and an ester group content of 10 wt% to 15 wt%.

5. The composite conductive nanoparticles according to any one of claims 1-4, characterized in that, In step (1), the carbon black dispersion solution-1 has a carbon black mass fraction of 1%-50%, preferably 1%-15%.

6. The composite conductive nanoparticles according to any one of claims 1-5, characterized in that, In step (2), polyhydroxyalkanoates account for 1%-60% of the mass of carbon black, preferably 5%-40%.

7. The composite conductive nanoparticles according to any one of claims 1-6, characterized in that, The preparation method of the composite conductive nanoparticles includes the following steps: according to the proportion, (a) The resin matrix, polyhydroxy fatty acid ester carbon black composite nano-conductive filler and optional processing aids are dispersed in an organic solvent to obtain a resin matrix dispersion and a polyhydroxy fatty acid ester carbon black composite nano-conductive filler dispersion. (b) Mix and disperse the two dispersions obtained in step (a) evenly, cool to room temperature to precipitate, and then perform post-treatment.

8. A method for preparing a semiconductor shielding material, comprising the following steps: according to a ratio, (1) Premixing: The polymer, the composite nano-conductive particles according to any one of claims 1-7, and optional processing aids are added to a mixer and stirred to obtain a premix; (2) Extrusion: The obtained premix is ​​granulated using a twin-screw extruder; (3) Post-absorption: Add DCP at 0.13% to 0.25 wt% of the raw material mass in step (1), shake well, let stand and absorb for 1 to 2 hours to obtain the semiconductor shielding material.

9. The method according to claim 8, characterized in that, The polymer comprises one or more of the following: ethylene-vinyl acetate copolymer, polyvinyl acetate, ethylene-butyl acrylate copolymer, and ethylene-acrylic acid copolymer.

10. The method according to claim 8 or 9, characterized in that, The mass ratio of the polymer to the composite conductive nanoparticles is 0–90:10–100.

Images