CN112342643A - High-thermal-conductivity carbon fiber powder and preparation method thereof - Google Patents
High-thermal-conductivity carbon fiber powder and preparation method thereof Download PDFInfo
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Abstract
本发明公开了一种高导热碳纤维粉及其制备方法，包括以下步骤：S10、进料：将短切高导热碳纤维通过料斗输送至粉碎腔；S20、分散：通入微正压气体并作用于粉碎腔，使短切高导热碳纤维均匀分散；S30、定向排列：在粉碎腔的两块电极板间施加高压电场作用，使短切高导热碳纤维定向有序排列；S40、高速气流粉碎：采用过滤后的压缩空气沿气流冲击板中的流道充入粉碎腔，将定向排布的短切高导热碳纤维精准粉碎，得到高导热碳纤维粉；S50、收集：释放电场，将高导热碳纤维粉进行收集。本发明提供的高导热碳纤维粉的制备方法中的气流压力可控，能有效防止纤维过度剪切粉碎；同时，纤维定向排列后研磨，粉碎效果能够满足所需的长度分布。
The invention discloses a high thermal conductivity carbon fiber powder and a preparation method thereof, comprising the following steps: S10, feeding: transporting chopped high thermal conductivity carbon fibers to a pulverizing cavity through a hopper; S20, dispersing: introducing a slightly positive pressure gas and acting on pulverization Cavity, so that the chopped high thermal conductivity carbon fibers are evenly dispersed; S30, directional arrangement: a high-voltage electric field is applied between the two electrode plates in the pulverizing cavity, so that the chopped high thermal conductivity carbon fibers are oriented and arranged in an orderly manner; S40, high-speed air pulverization: after filtering The compressed air is filled into the pulverizing cavity along the flow channel in the airflow impact plate, and the short-cut high thermal conductivity carbon fibers arranged in a direction are precisely pulverized to obtain high thermal conductivity carbon fiber powder; S50, collection: release the electric field, and collect the high thermal conductivity carbon fiber powder. In the preparation method of the high thermal conductivity carbon fiber powder provided by the present invention, the air pressure is controllable, which can effectively prevent the fibers from being excessively sheared and pulverized; meanwhile, the fibers are oriented and ground after being oriented, and the pulverizing effect can meet the required length distribution.
Description
Technical Field
The invention relates to a preparation method of special carbon fiber powder, in particular to high-thermal-conductivity carbon fiber powder and a preparation method thereof.
Background
With the rapid development of the 5G communication technology, the 5G product has the following characteristics: the high heat flow density (more than 50-100W/cm 2), the high power (a single chip is more than 1000W), the stability (continuous working time is 7 multiplied by 24h), the low time delay (microsecond level response), the appearance (product appearance is ultra-thin), and the high heat flow density puts higher requirements on the heat-conducting interface material. The traditional heat conducting pad material adopts spherical or flaky particles such as A12O3, AlN, BN and the like as heat conducting fillers, heat needs to be conducted through mutual contact among the particles, the particle filling amount is large, and the heat conductivity is generally 1-5W/m.K.
The novel heat-conducting interface material-carbon fiber heat-conducting pad can realize the highest heat conductivity of 50W/m.K and can meet the high heat dissipation requirement of the 5G industry. The high-thermal-conductivity mesophase pitch-based carbon fiber grinding powder used as the filler is directionally arranged in the silica gel matrix along the thickness direction, the requirement on the granularity (fiber length, length-diameter ratio and the like) of the carbon fiber powder is very high, the fiber length is too small, a good thermal conduction effect cannot be achieved, and the later-stage processing difficulty is increased due to the fact that the fiber length is too long. The heat-conducting interface material is made of high-heat-conducting carbon fiber grinding powder, and the common requirement is that the average length value is about hundreds of micrometers, the carbon fiber grinding powder is concentrated in a certain interval, and the length distribution is concentrated, so that the final product performance of the heat-conducting pad can be met.
The traditional particle grinding modes comprise planetary ball milling, jet milling, hobbing mill, wet grinding and the like, and the particle fineness is usually very small and is distributed below dozens of micrometers, but the traditional particle grinding mode is not suitable for grinding fibrous particles with the length-diameter ratio requirement. On one hand, the high-thermal-conductivity carbon fibers are very brittle and have poor bending and shearing resistance, so that the particle size requirement of the product cannot be met due to over-crushing even if the grinding time is short; on the other hand, because the fibers are in a random distribution state in the grinding cavity, the shearing and grinding process is basically uncontrollable, and bipolar differentiation of the fiber granularity is easily caused.
Disclosure of Invention
In order to solve the problems, the invention adopts the following technical scheme:
a preparation method of high-thermal-conductivity carbon fiber powder comprises the following steps:
s10, feeding: conveying the chopped high-heat-conductivity carbon fibers to a crushing cavity through a hopper;
s20, dispersing: introducing micro-positive pressure gas and acting on the crushing cavity to uniformly disperse the short-cut high-heat-conductivity carbon fibers;
s30, directional arrangement: applying a high-voltage electric field between the two electrode plates of the crushing cavity to ensure that the chopped high-heat-conductivity carbon fibers are directionally and orderly arranged;
s40, high-speed airflow crushing: filling filtered compressed air into the crushing cavity along a flow channel in the airflow impact plate, and accurately crushing the directionally arranged short-cut high-heat-conductivity carbon fibers to obtain high-heat-conductivity carbon fiber powder;
s50, collecting: releasing the electric field, and collecting the high-thermal-conductivity carbon fiber powder.
Further, in the step S10, the chopped high-thermal-conductivity carbon fibers have the axial thermal conductivity of 400-1100W/m.K, the modulus of 600-1000 GPa, the elongation at break of 0.1-0.5% and the length of 1-20 mm.
Further, in step S20, the pressure of the micro positive pressure gas is 5 to 50 kPa.
Further, in step S30, the voltage of the high voltage electric field is 10 to 50kV, and the distance between the electrode plates is 100 to 200 mm.
Further, in step S40, the airflow pressure of the compressed air is 0.2-0.8 MPa, the airflow impact plate is provided with a plurality of uniformly distributed flow channel grooves, and the distance between the central lines of the flow channel grooves is equal to the length average value of the required high-heat-conductivity carbon fiber powder.
Further, in step S50, a cyclone collector is used to collect the carbon fiber powder with high thermal conductivity.
Further, the length average value of the high-thermal-conductivity carbon fiber powder is 150-500 mu m; within the tolerance range of length mean value +/-100 mu m, the length number of the high-heat-conductivity carbon fiber powder accounts for >60 percent.
The high-thermal-conductivity carbon fiber powder used in the 5G field heat-conducting silica gel pad or heat-conducting glue is prepared by the preparation method of the high-thermal-conductivity carbon fiber powder.
Has the advantages that:
the preparation method of the high-thermal-conductivity carbon fiber powder provided by the invention has the advantages that the airflow pressure is controllable, and the excessive shearing and crushing of the fiber can be effectively prevented; meanwhile, the fibers are ground after being directionally arranged, and the crushing effect can meet the required length distribution; in addition, screening and subsequent repeated grinding through a grading wheel are not needed, and the production efficiency is improved.
Drawings
FIG. 1 is a flow chart of a preparation method of a carbon fiber powder with high thermal conductivity of the invention
FIG. 2 is a schematic view of the structure of the airflow impingement plate
Wherein, 1, airflow impact plate; 2. a runner groove.
Detailed Description
Example 1
A preparation method of high thermal conductivity carbon fiber powder (as shown in figure 1) comprises the following steps:
s10, selecting chopped high-heat-conductivity carbon fibers with the heat conductivity of 500W/m.K, the modulus of 750GPa, the elongation at break of 0.5 percent and the length of 3mm, and conveying the chopped high-heat-conductivity carbon fibers to a crushing cavity through a hopper;
s20, introducing micro-positive pressure gas of 20kPa into the crushing cavity to uniformly disperse the chopped high-heat-conductivity carbon fibers;
s30, applying a high-voltage electric field of 30kV between two electrode plates with the distance of 150mm in the crushing chamber to ensure that the chopped high-heat-conductivity carbon fibers are directionally and orderly arranged;
s40, filling compressed air with the air pressure of 0.6MPa after filtration into a crushing cavity along a flow channel groove in the airflow impact plate (the distance between the center lines of the flow channel grooves in the airflow impact plate is equal to 300 mu m), and accurately crushing the directionally arranged short high-heat-conductivity carbon fibers to obtain high-heat-conductivity carbon fiber powder;
and S50, releasing the electric field, and collecting the high-heat-conductivity carbon fiber powder by using a cyclone collector to obtain the high-heat-conductivity carbon fiber powder with the number ratio of 62% in the range of 200-400 mu m.
Example 2
S10, selecting short-cut high-heat-conductivity carbon fibers with the heat conductivity of 600W/m.K, the modulus of 800GPa, the elongation at break of 0.4% and the length of 5mm, and conveying the short-cut high-heat-conductivity carbon fibers to a crushing cavity through a hopper;
s20, introducing micro-positive pressure gas of 10kPa into the crushing cavity to uniformly disperse the chopped high-heat-conductivity carbon fibers;
s30, applying a 40kV high-voltage electric field effect between two electrode plates with the crushing chamber distance of 120mm to ensure that the chopped high-heat-conductivity carbon fibers are directionally and orderly arranged;
s40, filling compressed air with the air pressure of 0.4MPa after filtration into a crushing cavity along a flow channel groove in the airflow impact plate (the distance between the center lines of the flow channel grooves in the airflow impact plate is equal to 250 microns), and accurately crushing the directionally arranged short high-heat-conductivity carbon fibers to obtain high-heat-conductivity carbon fiber powder;
and S50, releasing the electric field, and collecting the high-heat-conductivity carbon fiber powder by using a cyclone collector to obtain 71% high-heat-conductivity carbon fiber powder within the range of 150-350 microns.
Example 3
S10, selecting chopped high-heat-conductivity carbon fibers with the heat conductivity of 800W/m.K, the modulus of 900GPa, the elongation at break of 0.3 percent and the length of 10mm, and conveying the chopped high-heat-conductivity carbon fibers to a crushing cavity through a hopper;
s20, introducing micro-positive pressure gas of 5kPa into the crushing cavity to uniformly disperse the chopped high-heat-conductivity carbon fibers;
s30, applying a 50kV high-voltage electric field between two electrode plates with the crushing chamber distance of 120mm to ensure that the chopped high-heat-conductivity carbon fibers are directionally and orderly arranged;
s40, filling compressed air with the air pressure of 0.35MPa after filtration into a crushing cavity along a flow channel groove in the airflow impact plate (the distance between the center lines of the flow channel grooves in the airflow impact plate is equal to 150 mu m), and accurately crushing the directionally arranged short high-heat-conductivity carbon fibers to obtain high-heat-conductivity carbon fiber powder;
and S50, releasing the electric field, and collecting the high-heat-conductivity carbon fiber powder by using a cyclone collector to obtain the high-heat-conductivity carbon fiber powder with the number percentage of 70% in the range of 50-250 microns.
Example 4
The high-thermal-conductivity carbon fiber powder used in the 5G field heat-conducting silica gel pad or heat-conducting glue is prepared by the preparation method of the high-thermal-conductivity carbon fiber powder in any one of the embodiment 1, the embodiment 2 or the embodiment 3.
The above description is only a preferred embodiment of the present invention, and is not intended to limit the technical scope of the present invention, so that any minor modifications, equivalent changes and modifications made to the above embodiment according to the technical spirit of the present invention are within the technical scope of the present invention.
Claims (8)
1. The preparation method of the high-thermal-conductivity carbon fiber powder is characterized by comprising the following steps of:
s10, feeding: conveying the chopped high-heat-conductivity carbon fibers to a crushing cavity through a hopper;
s20, dispersing: introducing micro-positive pressure gas and acting on the crushing cavity to uniformly disperse the short-cut high-heat-conductivity carbon fibers;
s30, directional arrangement: applying a high-voltage electric field between the two electrode plates of the crushing cavity to ensure that the chopped high-heat-conductivity carbon fibers are directionally and orderly arranged;
s40, high-speed airflow crushing: filling filtered compressed air into the crushing cavity along a flow channel in the airflow impact plate, and accurately crushing the directionally arranged short-cut high-heat-conductivity carbon fibers to obtain high-heat-conductivity carbon fiber powder;
s50, collecting: releasing the electric field, and collecting the high-thermal-conductivity carbon fiber powder.
2. The method for preparing the carbon fiber powder with high thermal conductivity according to claim 1, wherein in step S10, the chopped carbon fiber with high thermal conductivity has an axial thermal conductivity of 400-1100W/m.K, a modulus of 600-1000 GPa, an elongation at break of 0.1-0.5% and a length of 1-20 mm.
3. The method for preparing carbon fiber powder with high thermal conductivity according to claim 1, wherein in step S20, the pressure of the micro-positive pressure gas is 5 to 50 kPa.
4. The method for preparing carbon fiber powder with high thermal conductivity according to claim 1, wherein in step S30, the voltage of the high voltage electric field is 10-50 kV, and the distance between the electrode plates is 100-200 mm.
5. The method for preparing carbon fiber powder with high thermal conductivity according to claim 1, wherein in step S40, the airflow pressure of the compressed air is 0.2-0.8 MPa, the airflow impingement plate is provided with a plurality of uniformly distributed flow channel grooves, and the distance between the central lines of the flow channel grooves is equal to the length average value of the required carbon fiber powder with high thermal conductivity.
6. The method for preparing carbon fiber powder with high thermal conductivity as claimed in claim 5, wherein in step S50, a cyclone collector is used for collecting the carbon fiber powder with high thermal conductivity.
7. The method for preparing the carbon fiber powder with high thermal conductivity according to claim 6, wherein the average length of the carbon fiber powder with high thermal conductivity is 150-500 μm; within the tolerance range of length mean value +/-100 mu m, the length number of the high-heat-conductivity carbon fiber powder accounts for >60 percent.
8. A high thermal conductivity carbon fiber powder used in a thermal conductive silica gel pad or a thermal conductive adhesive in the 5G field, which is characterized by being prepared by the preparation method of the high thermal conductivity carbon fiber powder according to any one of claims 1 to 7.
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113564753A (en) * | 2021-07-05 | 2021-10-29 | 浙江大学 | Fiber dispersing and collecting device and method based on airflow impact and static electricity |
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| US5017312A (en) * | 1984-12-27 | 1991-05-21 | The Coe Manufacturing Company | Oriented chopped fiber mats and method and apparatus for making same |
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| US20170095981A1 (en) * | 2015-10-06 | 2017-04-06 | Florida State University Research Foundation, Inc. | Methods for Aligning Fibers with an Electrical Field and Composite Materials |
| US20170350048A1 (en) * | 2016-06-07 | 2017-12-07 | Hamilton Sundstrand Corporation | Short fiber composite material |
| JP2018193434A (en) * | 2017-05-12 | 2018-12-06 | Ａｃａ株式会社 | Press molding method of carbon fiber and press molded article |
| CN110230125A (en) * | 2019-05-21 | 2019-09-13 | 湖南东映碳材料科技有限公司 | A kind of preparation method of ultra-fine high thermal conductivity graphite fibre powder |
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Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5017312A (en) * | 1984-12-27 | 1991-05-21 | The Coe Manufacturing Company | Oriented chopped fiber mats and method and apparatus for making same |
| US20170095981A1 (en) * | 2015-10-06 | 2017-04-06 | Florida State University Research Foundation, Inc. | Methods for Aligning Fibers with an Electrical Field and Composite Materials |
| CN105482501A (en) * | 2015-11-26 | 2016-04-13 | 恩平燕怡新材料有限公司 | Wet airflow crushing dispersion method of nanometer calcium carbonate |
| US20170350048A1 (en) * | 2016-06-07 | 2017-12-07 | Hamilton Sundstrand Corporation | Short fiber composite material |
| JP2018193434A (en) * | 2017-05-12 | 2018-12-06 | Ａｃａ株式会社 | Press molding method of carbon fiber and press molded article |
| CN110230125A (en) * | 2019-05-21 | 2019-09-13 | 湖南东映碳材料科技有限公司 | A kind of preparation method of ultra-fine high thermal conductivity graphite fibre powder |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN113564753A (en) * | 2021-07-05 | 2021-10-29 | 浙江大学 | Fiber dispersing and collecting device and method based on airflow impact and static electricity |
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Address after: Room 2202, building F1, Lugu Yuyuan, No.27 Wenxuan Road, high tech Development Zone, Changsha City, Hunan Province Patentee after: Hunan Dongying Carbon Materials Technology Co.,Ltd. Patentee after: Hunan Dongying special carbon asphalt material Co.,Ltd. Address before: Room 2202, building F1, Lugu Yuyuan, No.27 Wenxuan Road, high tech Development Zone, Changsha City, Hunan Province Patentee before: HUNAN DONGYING CARBON MATERIAL TECHNOLOGY CO.,LTD. Patentee before: Hunan Dongying special carbon asphalt material Co.,Ltd. |
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Address after: 410000, No. 467 Xianjiahu West Road, Lugu Street, Xiangjiang New District, Changsha City, Hunan Province Patentee after: Hunan Dongying Carbon Materials Technology Co.,Ltd. Country or region after: China Patentee after: Hunan Dongying special carbon asphalt material Co.,Ltd. Address before: Room 2202, building F1, Lugu Yuyuan, No.27 Wenxuan Road, high tech Development Zone, Changsha City, Hunan Province Patentee before: Hunan Dongying Carbon Materials Technology Co.,Ltd. Country or region before: China Patentee before: Hunan Dongying special carbon asphalt material Co.,Ltd. |
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Effective date of registration: 20250529 Address after: 410000, No. 467 Xianjiahu West Road, Lugu Street, Xiangjiang New District, Changsha City, Hunan Province Patentee after: Hunan Dongying Carbon Materials Technology Co.,Ltd. Country or region after: China Address before: 410000, No. 467 Xianjiahu West Road, Lugu Street, Xiangjiang New District, Changsha City, Hunan Province Patentee before: Hunan Dongying Carbon Materials Technology Co.,Ltd. Country or region before: China Patentee before: Hunan Dongying special carbon asphalt material Co.,Ltd. |