CN114318931A - Method for preparing high-thermal-conductivity mica paper based on electric field orientation - Google Patents
Method for preparing high-thermal-conductivity mica paper based on electric field orientation Download PDFInfo
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- CN114318931A CN114318931A CN202111560131.1A CN202111560131A CN114318931A CN 114318931 A CN114318931 A CN 114318931A CN 202111560131 A CN202111560131 A CN 202111560131A CN 114318931 A CN114318931 A CN 114318931A
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Abstract
The invention discloses a preparation method of oriented high-thermal-conductivity mica paper, which comprises the following steps: 1) mixing and stirring heat-conducting filler, mica powder, water and adhesive, and placing prepared slurry with proper concentration into a head box; 2) making mica paper pulp under the action of a direct current electric field; 3) and squeezing, drying and cooling the paper material made by the paper, and finally performing calendaring modification. According to the invention, a direct current electric field is applied in the process of making the mica paper, so that the prepared mica paper has the excellent electrical property and air permeability, and the heat-conducting property is greatly improved.
Description
Technical Field
The invention belongs to the technical field of production and manufacture of main insulation mica paper of medium and large motors, and particularly relates to a method for manufacturing high-thermal-conductivity mica paper.
Technical Field
The conventional mica paper is made by beating the broken mica sheets into paper pulp by a chemical method or a hydraulic mechanical method, and then the paper pulp is processed into insulating paper which can be used in industry by papermaking, pressing, drying and calendaring on a paper machine. The prepared mica paper has uniform thickness and small dielectric strength fluctuation range, maintains various excellent characteristics of natural mica, and is a main material for stator insulation of high-voltage motors in China. In order to meet the new high-requirement standard continuously proposed by the national development for the motor industry, two methods are mainly used for improving the heat conductivity of the insulating layer at present: firstly, the thickness of the insulating layer is reduced, but the electric performance of the insulating layer is reduced due to the thinning of the insulating layer; secondly, the heat dissipation performance of the insulating material is improved under the condition of unchanged thickness, and the heat conductivity coefficient of the insulating material can be improved by adding a proper amount of heat-conducting filler into mica insulation. However, if the amount of the heat conductive filler is insufficient, the filler particles cannot contact with each other to form heat conductive paths, but the increase of the filler will result in the decrease of the electrical properties of the mica paper. Therefore, how to greatly improve the thermal conductivity of the mica paper insulating material with less filler and maintain good pressure resistance is an urgent problem to be considered and solved.
Disclosure of Invention
The invention provides a preparation method of a high-thermal-conductivity mica paper material for a high-voltage motor, aiming at solving the defect that the existing motor main insulation mica paper has low insulation level and poor thermal conductivity. By applying a uniform electric field to the mica pulp in the papermaking dehydration process, the mica paper filler forms a directional heat conduction channel in the direction vertical to the paper surface under the action of the electric field, and the finally prepared mica paper material has good heat conduction performance and air permeability and simultaneously keeps excellent electrical performance.
The invention is realized by the following technical scheme: a method for preparing oriented high-thermal-conductivity mica paper under the action of an electric field comprises the following steps:
(1) weighing a certain mass proportion of the heat-conducting filler, the binder and the dispersant, mixing and stirring uniformly.
(2) And (2) adding a proper amount of mica powder and the solution obtained in the step (1) into a certain mass of water, and stirring until the slurry is uniform.
(3) Polar plates are arranged on the upper part and the lower part of a lower blanket at the papermaking part of the cylinder paper machine, and direct current is supplied to the upper polar plate and the lower polar plate, so that a more uniform electric field is formed.
(4) And (4) feeding the slurry obtained in the step (3) into a slurry pool, and extracting the slurry onto a lower felt of a cylinder paper machine for papermaking. During the dewatering of the pulp, the heat conductive fillers are gradually arranged along the direction of the electric field, and heat conductive channels are formed thereby.
(5) And (4) carrying out squeezing and compacting treatment on the mica paper made and formed in the step (4), so that the density and the contact area of the heat-conducting filler in the direction vertical to the paper surface are increased while the mica scales are closely overlapped, and the heat-conducting property is increased. And finally, drying, cooling and coiling to obtain the required high-thermal-conductivity mica paper.
The binder is one or more of polyvidone, polyethylene glycol, methylcellulose, carboxymethylcellulose sodium or polyvinyl alcohol.
The high heat conductivity inorganic powder is one or more of boron nitride, silicon nitride, aluminum nitride, magnesium oxide, silicon oxide or aluminum oxide.
The dispersing agent is one or more of methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, sec-butanol, tert-butanol, acetic acid, acetone or toluene.
The mass ratio of the filler solution raw materials is as follows: heat-conducting filler: dispersant 1: 1-2: 1 to 10.
The mass ratio of the heat-conducting filler to the mica powder in the mica slurry is 1: 2-19, and adding water to adjust the solid content to 0.5% -1%.
In the papermaking process, polar plates are placed above and below the blanket, and the range of applied direct current voltage is 220V-1 kV.
Compared with the prior art, the invention has the beneficial effects that:
in the invention, the filler forms a good heat conduction channel vertical to the paper surface in the mica paper pulp dewatering and papermaking process, and the contact area of the heat conduction filler is increased after the pressing and compacting treatment. The prepared mica paper has higher thermal conductivity under the condition of less added fillers, and the original excellent performance of the mica paper is maintained to a certain extent. The heat dissipation capability of the motor insulation is effectively improved after the impregnation.
Detailed Description
Example (b): the following description is given by way of specific embodiments, and the advantages and effects of the present invention will be readily apparent to those skilled in the art from the disclosure herein.
(1) 1kg of polyvinyl alcohol and 2kg of boron nitride powder were weighed into 7kg of acetone, and the mixed filler solution was stirred at 1000 revolutions using a disperser.
(2) Weighing 7kg of mica powder, adding the mica powder and the uniformly mixed filler solution into 1000kg of water, and fully stirring to prepare mica slurry with the concentration of 1%.
(3) Polar plates are arranged on the upper and lower parts of a lower blanket at the papermaking position of the cylinder paper machine, and the upper and lower polar plates are electrified with 500V direct current voltage.
(4) And extracting the mica paper pulp to a paper machine, and papermaking under the action of an electric field. During the dewatering of the pulp, the heat conductive fillers are gradually arranged along the direction of the electric field, and heat conductive channels are formed thereby.
(5) The manufactured mica paper is pressed and compacted, so that the density and the contact area of the heat-conducting filler in the direction vertical to the paper surface are increased while the mica scales are closely overlapped, and the heat-conducting property is increased. And finally, drying, cooling and coiling to obtain the required high-thermal-conductivity mica paper.
In conclusion, compared with the existing products, the high-thermal-conductivity mica paper prepared by the invention has the advantages of low cost and simple preparation method. Under the condition of not changing a papermaking process, a direct current electric field is applied in the papermaking process of the mica paper, so that the heat-conducting fillers are arranged along the direction vertical to the paper surface, and a good heat-conducting channel is formed. The mica paper has higher heat conductivity under the condition of less filler consumption, simultaneously keeps excellent electrical performance, and can effectively improve the equipment maintenance time interval and prolong the service life.
It is to be understood that the invention is not limited to the specific embodiments described above, but is intended to cover various insubstantial modifications of the inventive process concepts and solutions, or its application to other applications without modification.
Claims (7)
1. The preparation method of the mica paper with high thermal conductivity is characterized by comprising the following steps:
(1) weighing a certain mass proportion of heat-conducting filler, a binder and a dispersant, mixing and uniformly stirring;
(2) adding a proper amount of mica powder and the solution obtained in the step (1) into water with a certain mass, and stirring until the slurry is uniform;
(3) polar plates are arranged on the upper part and the lower part of a lower blanket at the papermaking part of the cylinder paper machine, and direct current is supplied to the upper polar plate and the lower polar plate, so that a more uniform electric field is formed;
(4) feeding the pulp obtained in the step (3) into a pulp tank, extracting the pulp onto a lower felt of a cylinder paper machine for papermaking, and gradually arranging heat-conducting fillers along the direction of an electric field in the process of paper pulp dehydration to form a heat-conducting channel;
(5) and (4) carrying out squeezing and compacting treatment on the mica paper made and formed in the step (4), so that the density and the contact area of the heat-conducting filler in the direction vertical to the paper surface are increased while the mica scales are closely superposed, the heat-conducting property is increased, and finally, drying, cooling and coiling treatment are carried out to obtain the required high-heat-conducting mica paper.
2. The method for preparing mica paper with high thermal conductivity according to claim 1, wherein the binder in step (1) is one or more of povidone, polyethylene glycol, methylcellulose, carboxymethylcellulose, sodium carboxymethylcellulose, or polyvinyl alcohol.
3. The method for preparing mica paper with high thermal conductivity according to claim 1, wherein the inorganic powder with high thermal conductivity in step (1) is one or more of boron nitride, silicon nitride, aluminum nitride, magnesium oxide, silicon oxide or aluminum oxide.
4. The method for preparing mica paper with high thermal conductivity according to claim 1, wherein the dispersant in step (1) is one or more of methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, sec-butanol, tert-butanol, acetic acid, acetone or toluene.
5. The method for preparing mica paper with high thermal conductivity according to claim 1, wherein the mass ratio of the raw materials in the step (1) is binder: heat-conducting filler: dispersant 1: 1-2: 1 to 10.
6. The method for preparing mica paper with high thermal conductivity according to claim 1, wherein the mass ratio of the thermal conductive filler to the mica powder in the step (2) is 1: 2-19, and adding water to adjust the solid content to 0.5% -1%.
7. The method for preparing mica paper with high thermal conductivity according to claim 1, wherein in the papermaking process of step (3), polar plates are placed above and below a felt and a direct current voltage ranging from 500V to 1kV is applied.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111560131.1A CN114318931A (en) | 2021-12-20 | 2021-12-20 | Method for preparing high-thermal-conductivity mica paper based on electric field orientation |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202111560131.1A CN114318931A (en) | 2021-12-20 | 2021-12-20 | Method for preparing high-thermal-conductivity mica paper based on electric field orientation |
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Citations (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2001062850A (en) * | 1999-08-26 | 2001-03-13 | Tokai Rubber Ind Ltd | Manufacture of heat-conductive sheet and heat- conductive sheet obtained by the manufacturing method |
| US20020050585A1 (en) * | 2000-08-31 | 2002-05-02 | Tobita Masayuki | Heat conductive adhesive film and manufacturing method thereof and electronic component |
| US20050274774A1 (en) * | 2004-06-15 | 2005-12-15 | Smith James D | Insulation paper with high thermal conductivity materials |
| US20060234576A1 (en) * | 2005-04-15 | 2006-10-19 | Siemens Power Generation, Inc. | Patterning on surface with high thermal conductivity materials |
| US20110175259A1 (en) * | 2010-01-15 | 2011-07-21 | Lih-Sheng Turng | Method of Orientating Fillers in Composite Materials |
| CN103384743A (en) * | 2010-12-15 | 2013-11-06 | 康达利恩股份公司 | Method for forming an anisotropic conductive paper and a paper thus formed |
| CN103757977A (en) * | 2014-01-02 | 2014-04-30 | 雅安兴美云母工业有限责任公司 | Inorganic powder mica paper and preparation method and use thereof |
| US20160027549A1 (en) * | 2013-03-18 | 2016-01-28 | Siemens Aktiengesellschaft | Resistance covering for a dc insulation system |
| CN113416332A (en) * | 2021-06-23 | 2021-09-21 | 青岛科技大学 | Preparation method of high-thermal-conductivity three-phase composite film under assistance of electric field |
-
2021
- 2021-12-20 CN CN202111560131.1A patent/CN114318931A/en active Pending
Patent Citations (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2001062850A (en) * | 1999-08-26 | 2001-03-13 | Tokai Rubber Ind Ltd | Manufacture of heat-conductive sheet and heat- conductive sheet obtained by the manufacturing method |
| US20020050585A1 (en) * | 2000-08-31 | 2002-05-02 | Tobita Masayuki | Heat conductive adhesive film and manufacturing method thereof and electronic component |
| US20050274774A1 (en) * | 2004-06-15 | 2005-12-15 | Smith James D | Insulation paper with high thermal conductivity materials |
| US20060234576A1 (en) * | 2005-04-15 | 2006-10-19 | Siemens Power Generation, Inc. | Patterning on surface with high thermal conductivity materials |
| US20110175259A1 (en) * | 2010-01-15 | 2011-07-21 | Lih-Sheng Turng | Method of Orientating Fillers in Composite Materials |
| CN103384743A (en) * | 2010-12-15 | 2013-11-06 | 康达利恩股份公司 | Method for forming an anisotropic conductive paper and a paper thus formed |
| US20160027549A1 (en) * | 2013-03-18 | 2016-01-28 | Siemens Aktiengesellschaft | Resistance covering for a dc insulation system |
| CN103757977A (en) * | 2014-01-02 | 2014-04-30 | 雅安兴美云母工业有限责任公司 | Inorganic powder mica paper and preparation method and use thereof |
| CN113416332A (en) * | 2021-06-23 | 2021-09-21 | 青岛科技大学 | Preparation method of high-thermal-conductivity three-phase composite film under assistance of electric field |
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