A low-dust PVDF master batch based on a supported micro-nano conductive network and a preparation method and application thereof

Abstract

This application discloses a method for preparing low-dust-generating PVDF masterbatch based on a loaded micro / nano conductive network, specifically disclosing the preparation method as follows: Transition metal carbides are synthesized in situ on multi-walled carbon nanotubes in a solid phase, and a platinum shell is deposited to obtain a conductive building agent; then, 65%-80% of PVDF resin, 8%-15% of the conductive building agent, 5%-15% of PMMA-co-PMAA compatibilizer, and 1%-5% of fluorosilicone composite additive are mixed, melt-extruded, and continuously quenched in a constant-temperature water bath at 20℃-25℃ to lock crystal formation. The resulting PVDF masterbatch exhibits extremely low particle release, stable electrostatic dissipation, and high rigidity, and its metal ion precipitation meets the SEMI F57 ion precipitation requirements, making it suitable for ultra-clean equipment such as semiconductor wafer carriers. This application synthesizes transition metal carbides in situ on multi-walled carbon nanotubes and coats them with a platinum shell. The conductive network is locked by the coordination bond between the platinum shell and the compatibilizer, reducing filler shedding and achieving zero dust generation. A high-efficiency conductive pathway is constructed with a low filler ratio. A rapid cooling crystal-locking process and fluorosilicone additives are used to balance high rigidity, high rheological properties and mirror-like flatness.

Description

Technical Field

[0001] This application relates to the field of advanced engineering plastic materials technology that require high purity and high strength in semiconductors, and more specifically to a low-dust-generating PVDF masterbatch based on a loaded micro-nano conductive network, its preparation method, and its application. Background Technology

[0002] In semiconductor manufacturing processes such as wet etching, cleaning, and wafer transfer, the carrier equipment must simultaneously possess excellent chemical corrosion resistance, precise and stable electrostatic dissipation capabilities, and extremely high cleanliness, meaning that no particles must detach during use.

[0003] Vinylidene fluoride (PVDF) is considered the preferred substrate for load-bearing equipment in this field due to its good chemical resistance and mechanical strength; however, PVDF itself is an insulating material with a high volume resistivity, which cannot meet the functional requirements of electrostatic dissipation.

[0004] To impart electrical conductivity to PVDF, existing technologies commonly employ the method of blending conductive fillers into the PVDF matrix. Commonly used conductive fillers include carbon black and carbon nanotubes. This type of direct blending can reduce the volume resistivity of the material to some extent, but it reveals the following technical drawbacks in practical applications:

[0005] First, dust pollution is a prominent issue. When the equipment is exposed to a high-flow-rate chemical scouring environment for a long time, the filler particles are very easy to peel off and fall off from the substrate surface, forming particulate pollution, i.e., dust generation, which seriously threatens the cleanliness of the wafer and does not meet the ultra-clean requirements of semiconductor manufacturing.

[0006] Secondly, uneven packing dispersion leads to deterioration of overall mechanical properties. Conductive packing is prone to agglomeration in the PVDF matrix, making uniform dispersion difficult. This results in localized insulating or conductive overload areas within the material, compromising the uniformity and reliability of electrostatic dissipation performance. More importantly, the introduction of a large amount of rigid packing significantly disrupts the crystalline structure and crystallinity of PVDF, causing a sharp drop in the material's flexural modulus and elongation at break, severely weakening the mechanical load-bearing capacity and long-term reliability of the load-bearing equipment. Summary of the Invention

[0007] To address the aforementioned problems, this application provides a low-dust-generating PVDF masterbatch based on a loaded micro / nano conductive network, its preparation method, and its application.

[0008] Firstly, the method for preparing low-dust-generating PVDF masterbatch based on a loaded micro / nano conductive network provided in this application adopts the following technical solution:

[0009] A method for preparing low-dust-generating PVDF masterbatch based on a loaded micro / nano conductive network includes the following steps:

[0010] 1) Multi-walled carbon nanotubes are mixed with transition metal precursors and heat-treated in an inert atmosphere under solvent-free solid-phase conditions to synthesize transition metal carbide nanoparticles in situ and attach them to the conductive carrier of the multi-walled carbon nanotubes, thus obtaining a supported micro / nano conductive network building agent.

[0011] 2) Using the total mass of the final blended system as a calculation basis of 100%, weigh the following raw materials by mass percentage:

[0012] PVDF resin matrix: 65.0%-80.0%;

[0013] Step 1) The loaded micro / nano conductive network building agent obtained: 8.0%-15.0%;

[0014] Methyl methacrylate-methyl methacrylate copolymer (PMMA-co-PMAA) compatibilizer: 5.0%-15.0%;

[0015] Fluorosilicone composite processing modifier: 1.0%-5.0%;

[0016] 3) Add all the raw materials weighed in step 2) to a co-rotating twin-screw extruder for mixing and melt extrusion, and control the temperature of the melt shear zone of the extruder to be 210℃-220℃;

[0017] 4) The material extruded from the extruder die in step 3) is continuously introduced into a constant temperature water bath for cooling and crystal locking. The water temperature of the constant temperature water bath is controlled at 20℃-25℃. Then, after traction and pelletizing, the low dust-generating conductive PVDF masterbatch is obtained.

[0018] Further, in step 1), the transition metal precursor is selected from organometallic compounds or inorganic salts containing tungsten, molybdenum or titanium.

[0019] Furthermore, in step 1), the surface of the in-situ synthesized transition metal carbide nanoparticles is also coated with a platinum shell layer with a thickness of 0.25-0.5 nm.

[0020] Further, in step 1), the multi-walled carbon nanotube has an outer diameter of 10-20 nm, a length of 10-50 μm, and an aspect ratio ≥ 500.

[0021] Further, in step 2), the fluorosilicone composite processing modifier is compounded from a fluorinated elastomer and an ultra-high molecular weight silicone powder in a mass ratio of 1:1 to 3:1, wherein the fluorinated elastomer is selected from the polymer processing aid powder FE2650 of Taipuda New Materials; the high molecular weight silicone powder is preferably silicone powder with MW>50w, and in some embodiments it is selected from Chengdu Silike Technology LYSI-100A.

[0022] Further, in step 3), the co-rotating twin-screw extruder is provided with a feeding zone, a melt shearing zone, a vacuum exhaust zone and a die head zone in sequence along the material conveying direction; wherein the temperature of the vacuum exhaust zone is controlled at 225℃-235℃ and the vacuum degree is maintained at ≤-0.09MPa, and the screw speed is set to 280-320rpm.

[0023] Furthermore, there are no special restrictions on the molecular weight or the ratio of methyl methacrylate to methacrylic acid in the methyl methacrylate-methacrylic acid copolymer used in step 2).

[0024] Secondly, the low-dust-generating PVDF masterbatch based on a loaded micro / nano conductive network provided in this application adopts the following technical solution:

[0025] A low-dust-generating PVDF masterbatch based on a loaded micro / nano conductive network is prepared by the aforementioned method for preparing a low-dust-generating PVDF masterbatch based on a loaded micro / nano conductive network.

[0026] Furthermore, the test plate, which was injection molded after diluting the low-dust-generating conductive PVDF masterbatch with pure PVDF resin at a mass ratio of 1:3, exhibited a flexural modulus ≥1600MPa at 23°C and a volume resistivity of 10⁻⁶ MPa. 4 -10 5 The particle size distribution is 100 ohms·cm; and under the condition of pure water flushing at a flow rate of 2.5 m / s, the release rate of particles with a diameter ≥ 0.1 μm is ≤ 5 particles / mL·h, and the metal ion precipitation meets the relevant requirements of SEMI F57 ion precipitation.

[0027] Thirdly, the application of the low-dust-generating PVDF masterbatch based on a loaded micro / nano conductive network provided in this application adopts the following technical solution:

[0028] The application of the low-dust-generating PVDF masterbatch prepared by the above method in the preparation of wafer carriers, wherein the wafer carriers include wafer carriers.

[0029] In summary, this application has the following beneficial effects:

[0030] 1. This application adopts a structural design of in-situ solid-phase synthesis of transition metal carbides on multi-walled carbon nanotubes and coating them with an ultrathin platinum shell. The extremely stable "strong coordination complex" formed by the atomic vacancy d orbitals on the surface of the platinum shell and the lone pair electrons of the ester and carboxyl groups in the amphiphilic compatibilizer PMMA-co-PMAA is used to lock the inorganic conductive network into the polymer chain segment of the PVDF matrix. This reduces the peeling and shedding of conductive fillers under high-flow-rate chemical agents or ultrapure water rinsing environment, and the particle release rate drops sharply, which meets the stringent ultra-clean requirements of zero dust generation for wafer carriers in semiconductor manufacturing processes. At the same time, the metal ion precipitation of the material is controlled at a low level, which meets the high purity standards of semiconductors such as SEMI F57.

[0031] 2. The ultrathin platinum shell deposited by the ALD process in this application significantly reduces the barrier contact resistance between inorganic carbide nanoparticles and carbon nanotube carrier nodes due to the excellent metallic properties of platinum. Combined with the geometric overlap effect of high aspect ratio carbon nanotubes, this system only requires a low proportion of inorganic fillers to open up an efficient and continuous three-dimensional conductive path inside the matrix, reducing the risk of local insulation or large fluctuations in resistivity caused by general physical blending.

[0032] 3. This application utilizes a "rapid cooling and crystal locking" molding process to instantly freeze the deformation of the PVDF macromolecular chains after extrusion, locking in a dense, fine, and uniformly distributed α-phase microcrystalline state. This effectively avoids the displacement and damage to the inorganic conductive network caused by the growth of coarse spherulites during slow cooling, eliminates internal stress concentration, and maintains the material's flexural modulus at a high rigidity level of over 1600 MPa. Simultaneously, with the addition of a certain proportion of compounded fluorosilicone composite modifiers, the highly filled masterbatch is endowed with excellent rheological properties and mirror-level surface smoothness without the release of pollution sources. Detailed Implementation

[0033] The present invention will be described in detail below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention.

[0034] Unless otherwise specified, the experimental methods used in the following examples are conventional methods. Unless otherwise specified, the materials and reagents used in the following examples are all available through conventional commercial channels.

[0035] Example 1

[0036] A method for preparing low-dust-generating PVDF masterbatch based on a loaded micro / nano conductive network includes the following steps:

[0037] 1) Weigh out MWCNTs powder and ammonium heptamolybdate ((NH4)6Mo7O 24·4H2O) powder was added to a planetary ball mill at a mass ratio of 5:1 and ball milled at 300 rpm for 4 hours under solvent-free dry conditions to make the precursor uniformly and tightly adhered to the outer wall of the carbon nanotubes, thus obtaining a mixed powder.

[0038] The above mixed powder was transferred into a tube furnace, high-purity argon was introduced as a protective gas, and sponge titanium was placed in it. The furnace was heated to 900°C at a heating rate of 5°C / min and calcined at a constant temperature for 2 hours. During this high-temperature solid-state process, ammonium heptamolybdate decomposed into molybdenum oxide and was reduced in situ by carbon atoms on the surface of carbon nanotubes. Molybdenum carbide nanoparticles with a size of 5-10 nm were directly epitaxially grown on the carbon nanotube framework.

[0039] The above-mentioned carbon nanotube powder loaded with molybdenum carbide was placed in a fluidized bed atomic layer deposition reactor. MeCpPtMe3 was selected as the platinum precursor, and high-purity oxygen was used as the reaction gas. The ALD cycle was controlled as follows: the reaction chamber temperature was set at 250℃, the system substrate pressure was maintained at 1.0 Torr, MeCpPtMe3 gas was pulsed in for 2 seconds to achieve chemical adsorption saturation on the support surface; nitrogen gas was purged for 10 seconds to remove unreacted precursors; O2 reaction gas was pulsed in for 2 seconds to decompose the adsorbed precursors and generate a single atomic layer of Pt; nitrogen gas was purged again for 10 seconds. This constituted a complete ALD cycle. The thickness of Pt grown in a single cycle was about 0.1 nm. The number of ALD cycles was set to 3-5 times. After the reaction was completed, the supported micro-nano conductive network builder was obtained.

[0040] The MWCNTs have a specification of OD×L, 10-20nm×10-50μm; the fluorosilicone composite processing modifier is a compound of Taipuda New Materials FE2650 and Chengdu Silike Technology LYSI-100A in a mass ratio of 2:1.

[0041] 2) Using the total mass of the final blended system as a calculation basis of 100%, weigh the following raw materials by mass percentage:

[0042]

[0043] 3) Add all the raw materials weighed in step 2) to a co-rotating twin-screw extruder for mixing and melt extrusion, and control the temperature of the melt shear zone of the extruder to 210°C.

[0044] 4) The material extruded from the extruder die in step 3) is continuously introduced into a constant temperature water bath for cooling and crystal locking. The water temperature of the constant temperature water bath is controlled at 25°C. Then, the material is drawn and pelletized to obtain the low dust-generating conductive PVDF masterbatch.

[0045] Examples 2-4

[0046] A method for preparing low-dust-generating PVDF masterbatch based on a loaded micro / nano conductive network is described. The only difference from Example 1 is that the amount of each component in the mixing system in step 2) is different, as shown in the table below.

[0047]

[0048] Example 5

[0049] A method for preparing low-dust-generating PVDF masterbatch based on a loaded micro / nano conductive network, the only difference from Example 1 is that the MWCNTs have a specification of OD×L, 25-30nm×3-12μm.

[0050] Example 6

[0051] A method for preparing low-dust-generating PVDF masterbatch based on a loaded micro / nano conductive network, the only difference from Example 1, is that the fluorosilicone composite processing modifier is compounded by Taipuda New Materials FE2650 and Chengdu Silike Technology LYSI-100A in a mass ratio of 4:1.

[0052] Example 7

[0053] A method for preparing low-dust-generating PVDF masterbatch based on a loaded micro / nano conductive network, the only difference from Example 1, is that the fluorosilicone composite processing modifier is compounded by Taipuda New Materials FE2650 and Chengdu Silike Technology LYSI-100A in a mass ratio of 1:2.

[0054] Example 8

[0055] A method for preparing low-dust-generating PVDF masterbatch based on a loaded micro / nano conductive network, differing from Example 1 only in step 1), as detailed below:

[0056] Weigh out MWCNTs powder and ammonium heptamolybdate ((NH4)6Mo7O) 24 ·4H2O) powder was added to a planetary ball mill at a mass ratio of 5:1 and ball milled at 300 rpm for 4 hours under solvent-free dry conditions to make the precursor uniformly and tightly adhered to the outer wall of the carbon nanotubes, thus obtaining a mixed powder.

[0057] The above mixed powder was transferred into a tube furnace, and high-purity argon was introduced as a protective gas. The temperature was increased to 900°C at a heating rate of 5°C / min, and then calcined at a constant temperature for 2 hours. During this high-temperature solid-state process, ammonium heptamolybdate decomposed into molybdenum oxide and was reduced in situ by carbon atoms on the surface of carbon nanotubes. Molybdenum carbide nanoparticles with a size of 5-10 nm were directly epitaxially grown on the carbon nanotube framework, thus obtaining the supported micro-nano conductive network building agent.

[0058] Comparative Example 1

[0059] A method for preparing low-dust-generating PVDF masterbatch based on a loaded micro / nano conductive network, the only difference from Example 1 is that an equal amount of conventional conductive agent is used instead of the loaded micro / nano conductive network builder.

[0060] The conventional conductive agent is a physical mixture of free multi-walled carbon nanotubes and conductive carbon black, with a mass ratio of 5:1 between the free multi-walled carbon nanotubes and conductive carbon black, and the specifications of the conventional free multi-walled carbon nanotubes are consistent with those in Example 1.

[0061] Comparative Example 2

[0062] A method for preparing low-dust-generating PVDF masterbatch based on a supported micro / nano conductive network, the only difference from Example 1, is that the PMMA-co-PMAA compatibilizer was not added to the mixing system in step 2), and the mass percentages of other raw material components were adjusted accordingly, as follows:

[0063]

[0064] Comparative Example 3

[0065] A method for preparing low-dust-generating PVDF masterbatch based on a loaded micro / nano conductive network, differing from Example 1 only in the extrusion cooling molding process of step 4), as detailed below:

[0066] In step 4), the high-temperature strip material extruded from the twin-screw extruder die in step 3) is directly supported by the conveyor belt and exposed to the air environment at room temperature of 25°C for natural and slow cooling. After the strip material has naturally dissipated heat in the air and completely cooled and solidified, it is then pulled by the traction machine and sent to the pelletizer for pelletizing to obtain the conductive PVDF masterbatch of Comparative Example 3.

[0067] Performance testing

[0068] Before injection molding, the PVDF masterbatches prepared in each embodiment and comparative example were uniformly mixed with pure PVDF resin at a mass ratio of 1:3. The mixture was then added to the injection molding machine and injection molded into standard mechanical test strips and flat samples with dimensions of 100mm×100mm×3mm under the condition of a set temperature of 210℃-230℃. After being placed in a constant temperature and humidity environment (23℃, relative humidity 50%) for 48 hours for conditioning, the samples were tested.

[0069] 1. Electrical performance testing

[0070] Referring to the IEC60093 standard, a high-resistivity meter and a three-electrode test fixture were used to apply a test voltage and measure the volume resistivity (unit: ohms·cm) and surface resistivity (unit: ohms) of the sample.

[0071] 2. Mechanical performance testing

[0072] Tensile strength (yield) and elongation: according to ISO 527 standard, the test speed is 50 mm / min and the test temperature is 23℃;

[0073] Flexural modulus: According to ISO 178 standard, the test speed is 2 mm / min and the test temperature is 23℃;

[0074] Notched impact strength of simply supported beams: Tested according to ISO 180 standard at a test temperature of 23℃;

[0075] Shore hardness (Shore D): Tested according to ISO 868 standard at a test temperature of 23℃.

[0076] 3. Thermal properties

[0077] Melting temperature (DSC): Tested according to ISO 3146 standard;

[0078] Limiting Oxygen Index (LOI): Based on ASTM D2863, it measures the minimum oxygen concentration required to maintain stable combustion.

[0079] 4. Dynamic particulate matter release rate (dust generation) test

[0080] The flat sample was placed in an ultra-clean flow channel and the surface was continuously rinsed with ultrapure water (UPW) at a flow rate of 2.5 m / s for 2 hours. The release rate of solid particles with a diameter ≥ 0.1 μm in the rinsing liquid was detected in real time using a liquid particle counter (LPC).

[0081] 5. Metal ion precipitation test

[0082] The ultrapure water immersion extraction method specified in SEMI F57 standard was used to analyze the trace metal ion leaching of the sample and test whether the concentration of metal ion precipitation met the ultra-clean requirements related to semiconductor high-purity equipment materials.

[0083] The test results are shown in the table below.

[0084]

[0085] As can be seen from the data in Examples 1-4 above, the low-dust-generating conductive PVDF masterbatches prepared in Examples 1 to 4 all meet the stringent requirements of semiconductor-grade conductive substrates in terms of their various physical, mechanical, thermal, and cleanliness performance indicators. This indicates that the present application has high feasibility and excellent comprehensive technical effects within the defined formulation ratio range. By dynamically adjusting the absolute mass ratio of each component, the final macroscopic properties of the material can be controlled.

[0086] Example 1, with its component ratios of 70% PVDF resin, 15% conductive agent, 13% compatibilizer, and 2% additives, achieved a balance between mechanical rigidity, electrostatic dissipation, and extremely low dust generation. Its flexural modulus reached 1600 MPa, tensile yield strength was 40.0 MPa, and volume resistivity was maintained at a stable 2.5 × 10⁻⁶. 4 The dust emission rate is extremely low, at 1.2 particles / mL·h.

[0087] In Example 2, when the proportion of compatibilizer and fluorosilicone processing aid is increased, the interfacial slip and macromolecular flexible entanglement inside the system increase, and the particle release rate is further compressed to 0.8 particles / mL·h. However, due to the increase in the proportion of soft components, its flexural modulus decreases slightly to 1550MPa.

[0088] In Example 3, when the compatibilizer was significantly reduced to 5%, although the flexural modulus increased to 1680 MPa due to the increased continuity of the PVDF resin crystal regions, the particle release rate increased to 2.8 particles / mL·h due to the reduction in the total number of microscopic "chemical anchors".

[0089] In Example 4, when the conductive agent content decreased to 8%, it was likely approaching the percolation threshold of the micronetwork overlap, and the volume resistivity increased to 1.8 × 10⁻⁶. 5 The concentration of inorganic matter was 10 ohms·cm, but the lower inorganic content resulted in better interfacial integrity, and the amount of dust generated was reduced to 0.5 particles / mL·h.

[0090] In Example 5, the dimensions of the multi-walled carbon nanotubes were changed to a short, stout structure with a low aspect ratio. Test results showed that its volume resistivity deteriorated to 3.5 × 10⁻⁶. 5 The flexural modulus dropped to 1480 MPa, and the elongation at break plummeted from 23% to 14%. This indicates that the high aspect ratio carbon nanotube framework plays a key role in the system through a "geometric overlap effect," enabling efficient overlapping of continuous paths with extremely low volume fractions. If short and coarse fillers are used, the filler content must be forcibly increased in order to maintain the same conductivity level, which inevitably leads to severe stress concentration and thus degrades the inherent strong and tough mechanical properties of PVDF.

[0091] Example 1 uses a fluorine-silicon mass ratio of 2:1, and the sample surface exhibits a high degree of mirror flatness. In Example 6, when the proportion of fluorinated elastomer is too high, there is excessive external lubrication and slight insufficient internal lubrication. The apparent viscosity inside the screw increases slightly, and the resistivity fluctuates slightly.

[0092] In Example 7, when the proportion of ultra-high molecular weight silicone powder is too high, the excessive silicone molecular chains are over-lubricated inside the melt. Although this reduces energy consumption, the surface of the extruded sheet will show slight micro-extrusion texture because a sufficiently thick external lubricating dynamic protective film cannot be formed at the extrusion die. This indicates that a component blending ratio of 1:1 to 3:1 is the optimal range for maintaining continuous extrusion stability and a flawless surface morphology.

[0093] Furthermore, in Example 8, only the in-situ solid-state synthesis of the transition metal carbide molybdenum carbide was performed during the preparation of the supported micro / nano conductive network builder, omitting the step of atomic layer deposition to prepare the platinum shell. As can be seen from the data in Table 1, compared to the preferred Example 1, the material properties of Example 8 decreased: its volume resistivity increased by orders of magnitude (from 2.5 × 10⁻⁶). 4 Increased to 4.8×10 6 The dynamic particle release rate increased significantly to 18.5 particles / mL·h, which could no longer meet the stringent cleanliness requirements of advanced semiconductor processes for Wafer Cassette.

[0094] The possible reasons are:

[0095] 1) The ultrathin platinum shell, with its excellent metallic properties, greatly reduces the contact barrier between inorganic carbide nanoparticles and carbon nanotube carrier nodes, thus enabling the efficient electrostatic dissipation network to be established even with only 15% or even lower addition.

[0096] 2) The vacant d orbitals on the surface of platinum atoms may form extremely stable strong coordination complexes with the lone pairs of ester and carboxyl groups of the PMMA-co-PMAA amphiphilic compatibilizer in the system. In Example 8, due to the lack of the "key anchor point" of the platinum shell, the surface of the carbide particles is chemically inert and cannot form a strong interfacial lock with the compatibilizer and the matrix polymer chain. Therefore, when subjected to shearing and scouring of ultrapure water at a high flow rate of 2.5 m / s, the conductive network is very prone to peeling and detachment of the micro-interface, resulting in a sharp increase in dust generation.

[0097] Comparative Example 1 uses traditional physical blending of free multi-walled carbon nanotubes and conductive carbon black. Due to the lack of interfacial bonding, under continuous flushing with ultrapure water at a high flow rate of 2.5 m / s, the free filler particles undergo large-scale macroscopic exfoliation, with a particle release rate as high as 165.0 particles / mL·h. This cannot meet the cleanliness requirements of semiconductor process materials. Furthermore, at high filler content, the lack of compatibilizer and in-situ growth anchoring leads to severe macroscopic agglomeration of the free carbon nanotubes. A large amount of filler is encapsulated in the insulating polymer phase, failing to form an effective conductive path on a macroscopic scale. Therefore, the resistivity remains high and extremely unstable, while its flexural modulus drops significantly to 1320 MPa. Further analysis of Comparative Example 2 (complete removal of PMMA-co-PMAA compatibilizer) reveals that even with a platinum layer inside the filler, the dust emission of the sample after losing the compatibilizer still increases dramatically to 92.0 particles / mL·h, which precisely demonstrates the previously proposed viewpoint.

[0098] Comparative Example 3 employed natural slow cooling at the extrusion die. Test results showed that the flexural modulus of Comparative Example 3 dropped significantly to 1260 MPa. During the slow cooling process, the polymer chain segments inside the PVDF melt had sufficient time for long-range arrangement, thereby inducing the formation of coarse and non-uniform α-phase spherulites. These coarse grains exhibited a strong extrusion effect during growth, forcibly squeezing the inorganic conductive network to the grain boundary edge, resulting in severe local internal stress concentration and microscopic micropore defects. Under macroscopic mechanical stress, they were prone to cracking along the grain boundary. In contrast, Example 1 implemented continuous rapid cooling in a constant temperature water bath at 25°C, instantly freezing the chain segment deformation and forcibly locking the dense, fine, and highly uniformly distributed microcrystalline state, enabling the overall macroscopic framework to perfectly bear the high rigidity and high tensile yield strength of 1600 MPa.

[0099] The above are all modifications that can be made to this embodiment without contributing any inventive step, or solutions that clearly constitute technical teaching, after reading this specification. However, as long as they are within the scope of the claims of this application, they should be protected by patent law.

Claims

1. A method for preparing low-dust-generating PVDF masterbatch based on a loaded micro / nano conductive network, characterized in that, Includes the following steps: 1) Multi-walled carbon nanotubes are mixed with transition metal precursors and heat-treated in an inert atmosphere under solvent-free solid-phase conditions to synthesize transition metal carbide nanoparticles in situ and attach them to the conductive carrier of the multi-walled carbon nanotubes, thus obtaining a supported micro / nano conductive network building agent. 2) Using the total mass of the final blended system as a calculation basis of 100%, weigh the following raw materials by mass percentage: PVDF resin matrix: 65.0%-80.0%; Step 1) The loaded micro / nano conductive network building agent obtained: 8.0%-15.0%; Methyl methacrylate-methyl methacrylate copolymer (PMMA-co-PMAA) compatibilizer: 5.0%-15.0%; Fluorosilicone composite processing modifier: 1.0%-5.0%; The total mass of the system is the absolute sum of the amounts of the above-mentioned materials added. 3) Add all the raw materials weighed in step 2) to a co-rotating twin-screw extruder for mixing and melt extrusion, and control the temperature of the melt shear zone of the extruder to be 210℃-220℃; 4) The material extruded from the extruder die in step 3) is continuously introduced into a constant temperature water bath for cooling and crystal locking. The water temperature of the constant temperature water bath is controlled at 20℃-25℃. Then, after traction and pelletizing, the low dust-generating conductive PVDF masterbatch is obtained.

2. The method for preparing low-dust-generating PVDF masterbatch based on a loaded micro / nano conductive network according to claim 1, characterized in that, In step 1), the transition metal precursor is selected from organometallic compounds or inorganic salts containing tungsten, molybdenum or titanium.

3. The method for preparing low-dust-generating PVDF masterbatch based on a loaded micro / nano conductive network according to claim 1, characterized in that, In step 1), the surface of the in-situ synthesized transition metal carbide nanoparticles is also coated with a platinum shell layer with a thickness of 0.25-0.5 nm; the platinum shell layer is formed by 3-5 cycles of fluidized bed atomic layer deposition at 250 °C.

4. The method for preparing low-dust-generating PVDF masterbatch based on a loaded micro / nano conductive network according to claim 1, characterized in that, In step 1), the multi-walled carbon nanotubes have an outer diameter of 10-20 nm, a length of 10-50 μm, and an aspect ratio ≥ 500.

5. The method for preparing low-dust-generating PVDF masterbatch based on a loaded micro / nano conductive network according to claim 1, characterized in that, The fluorosilicone composite processing modifier is composed of a fluorinated elastomer and an ultra-high molecular weight silicone powder in a mass ratio of 1:1 to 3:1; wherein the ultra-high molecular weight silicone powder has a molecular weight > 500,000.

6. The method for preparing low-dust-generating PVDF masterbatch based on a loaded micro / nano conductive network according to claim 1, characterized in that, In step 3), the co-rotating twin-screw extruder is provided with a feeding zone, a melt shearing zone, a vacuum exhaust zone and a die head zone in sequence along the material conveying direction; wherein the temperature of the vacuum exhaust zone is controlled at 225℃-235℃ and the vacuum degree is maintained at ≤-0.09MPa, and the screw speed is set to 280-320rpm.

7. A low-dust-generating PVDF masterbatch based on a loaded micro / nano conductive network, characterized in that, The PVDF masterbatch is prepared by any one of the preparation methods described in claims 1-6.

8. The low-dust-generating PVDF masterbatch based on a loaded micro / nano conductive network according to claim 7, characterized in that, The test plate, formed by injection molding after diluting the low-dust-generating conductive PVDF masterbatch and pure PVDF resin at a mass ratio of 1:3, exhibits a flexural modulus ≥1600MPa at 23℃ and a volume resistivity of 10⁻⁶. 4 -10 5 The release rate of particles with a diameter ≥ 0.1 μm is ≤ 5 particles / mL·h under pure water flushing conditions at a flow rate of 2.5 m / s.

9. The application of the low-dust-generating PVDF masterbatch based on a load-type micro / nano conductive network as described in claim 7 or 8 in the preparation of antistatic bearing components for semiconductor wafer carriers or integrated circuit wet cleaning equipment.

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