CN115045140A - Aramid fiber insulating paper reinforced by inorganic nano material and preparation method and application thereof - Google Patents
Aramid fiber insulating paper reinforced by inorganic nano material and preparation method and application thereof Download PDFInfo
- Publication number
- CN115045140A CN115045140A CN202210474616.7A CN202210474616A CN115045140A CN 115045140 A CN115045140 A CN 115045140A CN 202210474616 A CN202210474616 A CN 202210474616A CN 115045140 A CN115045140 A CN 115045140A
- Authority
- CN
- China
- Prior art keywords
- aramid
- paper
- layer
- inorganic nano
- nano material
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 239000002086 nanomaterial Substances 0.000 title claims abstract description 130
- 229920006231 aramid fiber Polymers 0.000 title claims abstract description 49
- 238000002360 preparation method Methods 0.000 title claims abstract description 23
- 229920003235 aromatic polyamide Polymers 0.000 claims abstract description 122
- 239000004760 aramid Substances 0.000 claims abstract description 118
- 239000010410 layer Substances 0.000 claims abstract description 101
- 238000005507 spraying Methods 0.000 claims abstract description 33
- 238000009413 insulation Methods 0.000 claims abstract description 32
- 239000006185 dispersion Substances 0.000 claims abstract description 30
- 239000002356 single layer Substances 0.000 claims abstract description 24
- 238000000034 method Methods 0.000 claims abstract description 20
- 238000003825 pressing Methods 0.000 claims abstract description 20
- 238000007731 hot pressing Methods 0.000 claims abstract description 18
- 238000009826 distribution Methods 0.000 claims abstract description 17
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 17
- 238000001035 drying Methods 0.000 claims abstract description 13
- 238000013329 compounding Methods 0.000 claims abstract description 10
- 230000008021 deposition Effects 0.000 claims abstract description 5
- 239000000835 fiber Substances 0.000 claims description 15
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 9
- 239000007788 liquid Substances 0.000 claims description 9
- 239000002245 particle Substances 0.000 claims description 9
- 239000007921 spray Substances 0.000 claims description 9
- 239000000377 silicon dioxide Substances 0.000 claims description 6
- 239000000843 powder Substances 0.000 claims description 4
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 claims description 3
- XLOMVQKBTHCTTD-UHFFFAOYSA-N Zinc monoxide Chemical compound [Zn]=O XLOMVQKBTHCTTD-UHFFFAOYSA-N 0.000 claims description 3
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 claims description 3
- 238000004519 manufacturing process Methods 0.000 claims description 3
- 239000005543 nano-size silicon particle Substances 0.000 claims description 3
- PZNSFCLAULLKQX-UHFFFAOYSA-N Boron nitride Chemical compound N#B PZNSFCLAULLKQX-UHFFFAOYSA-N 0.000 claims description 2
- 239000010445 mica Substances 0.000 claims description 2
- 229910052618 mica group Inorganic materials 0.000 claims description 2
- 229910010271 silicon carbide Inorganic materials 0.000 claims description 2
- 239000011787 zinc oxide Substances 0.000 claims description 2
- HBMJWWWQQXIZIP-UHFFFAOYSA-N silicon carbide Chemical compound [Si+]#[C-] HBMJWWWQQXIZIP-UHFFFAOYSA-N 0.000 claims 1
- 239000002131 composite material Substances 0.000 abstract description 7
- 230000015556 catabolic process Effects 0.000 abstract description 6
- 230000000694 effects Effects 0.000 description 10
- 239000000463 material Substances 0.000 description 9
- 230000008569 process Effects 0.000 description 8
- 238000010586 diagram Methods 0.000 description 5
- 239000012466 permeate Substances 0.000 description 5
- 238000009792 diffusion process Methods 0.000 description 4
- 239000000945 filler Substances 0.000 description 4
- 239000011810 insulating material Substances 0.000 description 4
- 238000012423 maintenance Methods 0.000 description 4
- 230000036961 partial effect Effects 0.000 description 4
- 230000002829 reductive effect Effects 0.000 description 4
- 239000002002 slurry Substances 0.000 description 4
- 239000000243 solution Substances 0.000 description 4
- 239000004840 adhesive resin Substances 0.000 description 3
- 229920006223 adhesive resin Polymers 0.000 description 3
- 230000008901 benefit Effects 0.000 description 3
- 230000000052 comparative effect Effects 0.000 description 3
- 230000006378 damage Effects 0.000 description 3
- 238000010292 electrical insulation Methods 0.000 description 3
- 230000004048 modification Effects 0.000 description 3
- 238000012986 modification Methods 0.000 description 3
- 238000011160 research Methods 0.000 description 3
- 239000000126 substance Substances 0.000 description 3
- 230000009471 action Effects 0.000 description 2
- 239000000654 additive Substances 0.000 description 2
- 239000000853 adhesive Substances 0.000 description 2
- 230000001070 adhesive effect Effects 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 2
- 230000007547 defect Effects 0.000 description 2
- 230000018044 dehydration Effects 0.000 description 2
- 238000006297 dehydration reaction Methods 0.000 description 2
- 239000002270 dispersing agent Substances 0.000 description 2
- 238000003912 environmental pollution Methods 0.000 description 2
- 238000002156 mixing Methods 0.000 description 2
- 238000001556 precipitation Methods 0.000 description 2
- 239000002994 raw material Substances 0.000 description 2
- 238000005096 rolling process Methods 0.000 description 2
- 230000035882 stress Effects 0.000 description 2
- 239000000725 suspension Substances 0.000 description 2
- 229920001187 thermosetting polymer Polymers 0.000 description 2
- 239000012790 adhesive layer Substances 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 238000004220 aggregation Methods 0.000 description 1
- 230000002776 aggregation Effects 0.000 description 1
- 230000032683 aging Effects 0.000 description 1
- 239000007864 aqueous solution Substances 0.000 description 1
- 238000010009 beating Methods 0.000 description 1
- 239000003153 chemical reaction reagent Substances 0.000 description 1
- 230000001010 compromised effect Effects 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 238000005485 electric heating Methods 0.000 description 1
- 239000002657 fibrous material Substances 0.000 description 1
- 238000005098 hot rolling Methods 0.000 description 1
- 230000002401 inhibitory effect Effects 0.000 description 1
- 238000011031 large-scale manufacturing process Methods 0.000 description 1
- 230000000670 limiting effect Effects 0.000 description 1
- 239000011259 mixed solution Substances 0.000 description 1
- 238000005457 optimization Methods 0.000 description 1
- 230000035515 penetration Effects 0.000 description 1
- 230000000704 physical effect Effects 0.000 description 1
- 230000002035 prolonged effect Effects 0.000 description 1
- 230000001737 promoting effect Effects 0.000 description 1
- 238000011084 recovery Methods 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
- 235000012239 silicon dioxide Nutrition 0.000 description 1
- 239000004094 surface-active agent Substances 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
- 238000009210 therapy by ultrasound Methods 0.000 description 1
- 238000003878 thermal aging Methods 0.000 description 1
- 230000008646 thermal stress Effects 0.000 description 1
- 230000003313 weakening effect Effects 0.000 description 1
Images
Classifications
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
- D21H27/00—Special paper not otherwise provided for, e.g. made by multi-step processes
- D21H27/30—Multi-ply
- D21H27/32—Multi-ply with materials applied between the sheets
- D21H27/34—Continuous materials, e.g. filaments, sheets, nets
- D21H27/36—Films made from synthetic macromolecular compounds
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B29/00—Layered products comprising a layer of paper or cardboard
- B32B29/002—Layered products comprising a layer of paper or cardboard as the main or only constituent of a layer, which is next to another layer of the same or of a different material
- B32B29/005—Layered products comprising a layer of paper or cardboard as the main or only constituent of a layer, which is next to another layer of the same or of a different material next to another layer of paper or cardboard layer
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B29/00—Layered products comprising a layer of paper or cardboard
- B32B29/06—Layered products comprising a layer of paper or cardboard specially treated, e.g. surfaced, parchmentised
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
- D21H13/00—Pulp or paper, comprising synthetic cellulose or non-cellulose fibres or web-forming material
- D21H13/10—Organic non-cellulose fibres
- D21H13/20—Organic non-cellulose fibres from macromolecular compounds obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds
- D21H13/26—Polyamides; Polyimides
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
- D21H15/00—Pulp or paper, comprising fibres or web-forming material characterised by features other than their chemical constitution
- D21H15/02—Pulp or paper, comprising fibres or web-forming material characterised by features other than their chemical constitution characterised by configuration
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
- D21H19/00—Coated paper; Coating material
- D21H19/36—Coatings with pigments
- D21H19/38—Coatings with pigments characterised by the pigments
- D21H19/385—Oxides, hydroxides or carbonates
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
- D21H19/00—Coated paper; Coating material
- D21H19/36—Coatings with pigments
- D21H19/38—Coatings with pigments characterised by the pigments
- D21H19/40—Coatings with pigments characterised by the pigments siliceous, e.g. clays
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
- D21H21/00—Non-fibrous material added to the pulp, characterised by its function, form or properties; Paper-impregnating or coating material, characterised by its function, form or properties
- D21H21/50—Non-fibrous material added to the pulp, characterised by its function, form or properties; Paper-impregnating or coating material, characterised by its function, form or properties characterised by form
- D21H21/52—Additives of definite length or shape
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B2250/00—Layers arrangement
- B32B2250/03—3 layers
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B2250/00—Layers arrangement
- B32B2250/26—All layers being made of paper or paperboard
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P20/00—Technologies relating to chemical industry
- Y02P20/10—Process efficiency
Landscapes
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Dispersion Chemistry (AREA)
- Insulating Bodies (AREA)
- Chemical Or Physical Treatment Of Fibers (AREA)
- Laminated Bodies (AREA)
Abstract
The invention provides an inorganic nano material reinforced aramid fiber insulation paper and a preparation and application method thereof. The aramid insulating paper reinforced by the inorganic nano material is applied to motor electrical equipment and comprises a plurality of aramid paper layers and an inorganic nano material doping distribution layer positioned between every two adjacent aramid paper layers; the inorganic nano material doping distribution layer is a deposition layer of inorganic nano material aqueous dispersion. The preparation method comprises the following steps: uniformly spraying a layer of inorganic nano material water dispersion on the upper surface of single-layer aramid base paper, and performing vacuum suction on the surface which is not sprayed with the inorganic nano material water dispersion to obtain double-layer aramid paper with one layer of an inorganic nano material doped distribution layer and the other layer of a pure aramid paper layer; and carrying out cold pressing compounding on the other single-layer aramid raw paper and the obtained inorganic nano material spraying surface of the double-layer aramid paper, and then drying and hot pressing to obtain the composite aramid paper. The aramid fiber insulation paper has stronger corona resistance and higher dielectric breakdown strength.
Description
Technical Field
The invention belongs to the field of aramid fiber materials, and particularly relates to an inorganic nano material reinforced aramid fiber insulating material as well as a preparation method and application thereof.
Background
The aramid fiber insulation paper is special fiber paper made by mixing aramid fiber chopped fibers and aramid fiber fibrids according to a certain proportion, and is widely applied as an insulation protection material in various types of electrical equipment such as medium-high voltage motors, reactors, transformers and the like due to excellent mechanical, chemical, electrical and thermal aging resistance physical properties.
In recent years, as devices such as new energy motors, reactors, and transformers are being made lighter, smaller, higher frequency, and higher power, the internal components of the motors are subjected to higher pulse voltage stress, mechanical stress, and thermal stress. After the motor is frequently started and used for a long time, an insulation system is more easily damaged and fails, and frequent maintenance is needed, so that the requirement on the insulation structure material of the motor is higher and higher. As one of important insulating materials, the dielectric protection performance of aramid insulating paper directly influences the service life, maintenance cost and enterprise benefit of motor electrical equipment. In order to further improve the service life of electrical equipment, many researchers have developed the electrical insulation property optimization and modification research on aramid insulation paper. Researches show that the inorganic nano material has excellent electrical insulation characteristics in the aspects of inhibiting space charge aggregation, reducing carrier movement rate and weakening overload pulse voltage, and researchers make a great deal of research work on the aspect of doping the inorganic nano material with modified aramid paper. The invention discloses a preparation method of nano-silica reinforced meta-aramid paper, which is characterized in that meta-aramid chopped fibers are treated by a surfactant aqueous solution and then mixed with meta-aramid pulp according to a certain proportion to prepare aramid fiber pulp, then nano-silica subjected to ultrasonic treatment is added into the pulp to obtain mixed suspension, the mixed suspension is subjected to dehydration forming, wet pressing and drying to obtain aramid base paper, and the aramid base paper is subjected to hot pressing to obtain the inorganic nano-material reinforced aramid paper. The method mixes the inorganic nano material with the aramid fiber slurry, and easily causes the loss of the inorganic nano filler and other dispersant chemical additives along with the loss of the slurry and the harm of environmental pollution in the dehydration forming process of the mixed solution, so the method still needs to be improved; the second method is, for example, application No. 202110293897.1 entitled composite aramid paper with high dielectric property, and is characterized in that single-layer aramid paper is bonded and combined into a whole through an adhesive layer containing inorganic nano filler, and finally the inorganic nano material reinforced modified composite aramid paper is formed.
Disclosure of Invention
In order to meet the requirement of high electrical performance of insulating materials in electrical equipment, the aramid fiber insulating paper reinforced by inorganic nano materials is prepared, has stronger corona resistance and higher dielectric breakdown strength than common aramid fiber insulating paper, can enable a motor to have better protection effect on overload pulse voltage, and can effectively protect electrical equipment such as the motor, a reactor, a transformer and the like; the service life of the electrical equipment is prolonged, and the maintenance cost is reduced.
The technical scheme adopted by the invention is as follows:
the aramid insulating paper reinforced by the inorganic nano material comprises a plurality of aramid paper layers and an inorganic nano material doping distribution layer between every two adjacent aramid paper layers; the inorganic nano material doping distribution layer is a deposition layer of inorganic nano material aqueous dispersion.
Preferably, in the technical scheme, the content of the inorganic nano material in the aramid fiber insulating paper reinforced by the inorganic nano material is 0.01-10 g/m 2 。
Preferably, the aramid paper layer is a meta-aramid paper layer or a para-aramid paper layer.
Preferably, the meta-aramid paper layer contains 40-70 parts of precipitation fiber and 30-60 parts of chopped fiber; the para-aramid paper layer comprises 50-80 parts of fibrids and 20-50 parts of chopped fibers. The meta-aramid fiber adopts precipitation fiber with large specific surface area and chopped fiber with compromised mechanical property, and makes full use of the performance advantages of the respective fibers, so that the prepared aramid fiber insulating paper has excellent mechanical strength and dielectric property comprehensive properties.
Based on the same technical idea, the invention also provides a preparation method of the inorganic nano-material reinforced aramid fiber insulation paper, and the preparation process comprises the following steps:
(1) uniformly spraying a layer of inorganic nano material water dispersion on the upper surface of the single-layer aramid raw paper to obtain aramid raw paper with an initial hybrid structure;
(2) carrying out vacuum suction on the aramid raw paper with the initial hybrid structure obtained in the step (1) from the side which is not sprayed with the inorganic nano material aqueous dispersion to obtain aramid paper with a double-layer structure, wherein one layer is an inorganic nano material doped distribution layer, and the other layer is a pure aramid paper layer;
(3) carrying out cold pressing compounding on the other single-layer aramid base paper and the inorganic nano material spraying surface of the double-layer aramid paper obtained in the step (2) to obtain three-layer aramid paper with the middle layer containing the inorganic nano material;
(4) and (4) drying and hot-pressing the aramid fiber paper with the intermediate layer containing the aramid fiber three-layer structure of the inorganic nano material obtained in the step (3) to obtain the aramid fiber insulating paper reinforced by the inorganic nano material.
Preferably, in the preparation processes (1) and (3), the gram weight of the single-layer aramid base paper is 10-180 g/m 2 . The gram weight of the single-layer aramid raw paper has influence on the composite hot pressing effect and the paper forming performance; the gram weight of the base paper is too low, holes and needle paper defects are easy to generate, and the hot-pressing composite forming is not facilitated; the gram weight is too high, heat is difficult to penetrate during hot-pressing compounding, the hot-pressing compounding effect is influenced, and finally the performance of the paper is influenced.
Preferably, in the preparation processes (1) and (3), the gram weight of the single-layer aramid base paper is 12-120 g/m 2 . Generally, the larger the gram weight is, the higher the mechanical properties of the paper are, but the flexibility and application processability of the paper are reduced, so the single-layer aramid base paper in the gram weight range is further preferred by the invention through comprehensive balance.
Preferably, in the technical scheme, the tightness of the single-layer aramid base paper is 0.20-0.68 g/cm 3 . Because the inorganic nano material is applied by spraying, the diffusion and permeation degree of the nano material in the base paper can be influenced by the tightness, the tightness is too high, the inorganic nano material is not favorably permeated and distributed in the aramid base paper, and the inorganic nano material is easy to permeate excessively to cause material overflow and leakage when the tightness is too low.
Preferably, in the technical scheme, the moisture content of the single-layer aramid base paper is 1.0-20.0%. The water content of the base paper can influence the spraying, permeating and diffusing effect of the inorganic nano material aqueous dispersion in the aramid base paper, the water content of the base paper is too high, the diffusion and permeation of the inorganic nano material aqueous dispersion in the aramid base paper are not facilitated, the water content is too low, the material is easy to be too dry and brittle, and the drawing and the breaking are easy to occur, so that the water content range of the base paper is limited.
Preferably, in the above technical solution, the inorganic nano-material in the inorganic nano-material aqueous dispersion is one or a combination of two or more of nano-zinc oxide, nano-silica, nano-alumina, nano-titania, nano-silicon carbide, nano-boron nitride and nano-mica powder.
Preferably, in the above-mentioned technical means, the particle size of the inorganic nanomaterial in the aqueous dispersion of inorganic nanomaterial is 10 to 100 nm. The particle size of the inorganic nano material body is selected in such a range to facilitate the penetration and diffusion of the inorganic nano material body to the inner layer of the aramid paper.
Preferably, in the above technical solution, the inorganic nanomaterial aqueous dispersion comprises 0.1 to 30 parts of inorganic nanomaterial and 70 to 99.9 parts of water.
Preferably, in the step (1), the spraying is carried out by using a high-pressure air spray gun, the spraying hydraulic pressure of the high-pressure air spray gun is 0.01-1.0 MPa, the spraying air pressure is 0.1-5.0 MPa, and the particle size of the sprayed liquid drop is 2-10 μm. The spraying air pressure and hydraulic pressure of the spray gun have important influence on the permeation and diffusion effect of the inorganic nano material in the paper and the final performance of the paper, the pressure is too low, the inorganic nano material is difficult to deeply permeate into the paper base material, the uniform dispersion is not facilitated, the pressure is too high, the impact damage to the paper machine material is easy to cause, and therefore the parameter range is confirmed according to the actual test effect.
Preferably, in the step (2), the vacuum suction is performed by using a vacuum guide roller, and the vacuum degree of the vacuum guide roller is-0.1 to-100 kPa.
Preferably, in the step (3), a cold pressing roller is adopted during cold pressing compounding, the cold pressing temperature is 0-50 ℃, and the cold pressing pressure is 0.2-30 MPa.
Preferably, in the step (4), the drying temperature in the drying process is 100-300 ℃; the hot pressing temperature is 250-400 ℃, and the hot pressing pressure is 5-50 MPa.
Preferably, in the step (1), the spraying process of the inorganic nano-materials is performed in a semi-closed box, and a negative pressure suction recovery device is communicated with the semi-closed box, so that the surplus inorganic nano-material dispersion liquid which is not absorbed by the aramid paper is sprayed and absorbed and recycled.
Based on the same technical idea, the invention also provides an application method of the aramid fiber insulation paper reinforced by the inorganic nano material, which is characterized in that the aramid fiber insulation paper reinforced by the inorganic nano material is applied to track traction motors, transformers, wind motors, reactors, new-energy high-frequency high-voltage light motors and other motor and electrical equipment; the application thickness of the inorganic nano material reinforced aramid fiber insulating paper is 0.03-0.8 mm.
Compared with the prior art, the invention has the beneficial effects that:
(1) the aramid fiber insulating paper disclosed by the invention is enhanced by adopting the inorganic nano material, so that the aramid fiber insulating paper has stronger corona resistance and higher dielectric breakdown strength. And because the aramid fiber insulating paper reinforced by the inorganic nano material is of a multilayer structure, and an inorganic nano material doping distribution layer is arranged between two adjacent aramid fiber paper layers, a proper aramid fiber paper layer can be arranged according to the requirement on the electrical performance of the insulating material in electrical equipment, and the aramid fiber insulating paper is convenient to prepare and has higher flexibility. The inorganic nano material doping distribution layer is a deposition layer of inorganic nano material aqueous dispersion. Because the aramid base paper is in a loose porous structure, the inorganic nano material water dispersion liquid is easy to permeate and diffuse to the inner layer of the aramid base paper in the compounding process of the aramid base paper, so that the deposition layer of the inorganic nano material water dispersion liquid is used as the inorganic nano material doping distribution layer to strengthen the combination effect of the inorganic nano material and the aramid base paper, and the prepared inorganic nano material reinforced aramid insulation paper is more stable in performance. The inorganic nano material doped distribution layer also avoids the problem that the composite of an adhesive and an aramid raw paper layer in the prior art is easy to become hard and brittle after thermosetting.
(2) According to the invention, the aramid paper is sprayed and doped with the inorganic nano material by using the high-pressure air spray gun, so that the problems that the loss of the inorganic nano filler and other dispersant chemical additives along with the loss of the slurry and the harm of environmental pollution are easily caused by a slurry mixing, dehydrating and doping forming mode can be avoided, and the production process is more environment-friendly and economical;
(3) the inorganic nano material reinforced aramid fiber insulation paper only consists of pure aramid fiber paper materials and inorganic nano materials, does not contain low-heat-resistance adhesive resin components or other doped modified low-dielectric organic components, reduces the risk that the material is easy to generate electric heating aging breakdown in a high-frequency high-voltage electrical application environment, is beneficial to promoting the electrical insulation performance of the aramid fiber insulation paper to be optimized and improved, and simultaneously avoids the adverse effect that volatile organic matters are easy to generate in the curing process of the adhesive. In addition, because the aramid paper does not contain thermosetting adhesive resin materials, the defect that the aramid paper is hard and brittle easily caused by containing adhesive resin components after composite curing is avoided, and the aramid paper has better flexibility and process adaptability.
(4) The doping amount of the inorganic nano material in the aramid fiber insulating paper can be flexibly regulated and controlled by the spraying hydraulic pressure and the air pressure of a high-pressure spray gun, the preparation process is simple to operate, the process is environment-friendly, large-scale production is facilitated, and the number of the inorganic nano filler can be changed by adjusting the number of single-layer aramid fiber paper layers and the number of inorganic nano material doping distribution layers according to actual conditions, so that the aramid fiber insulating paper meets higher dielectric property requirements.
Drawings
In order to more clearly illustrate the embodiments or technical solutions in the prior art of the present invention, the drawings used in the description of the embodiments or prior art will be briefly described below, and it is obvious for those skilled in the art that other drawings can be obtained based on these drawings without creative efforts.
FIG. 1 is a schematic view of a structure of an inorganic nano-material reinforced aramid insulation paper;
fig. 2 is a schematic diagram of a preparation process of the inorganic nano-material reinforced aramid insulation paper.
Wherein: 1. an aramid paper layer; 2. the inorganic nanomaterial-doped distribution layer.
Detailed Description
In order to facilitate an understanding of the invention, the invention is described more fully and in detail below, but the scope of the invention is not limited to the following specific examples.
Unless otherwise defined, all terms of art used hereinafter have the same meaning as commonly understood by one of ordinary skill in the art. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of the present invention.
Unless otherwise specifically stated, various raw materials, reagents, instruments, equipment and the like used in the present invention are commercially available or can be prepared by existing methods.
Example 1:
a preparation method of aramid fiber insulating paper reinforced by inorganic nano materials is shown in a schematic process flow diagram of figure 2 and comprises the following steps:
(1) under the conditions that the spraying hydraulic pressure is 0.15MPa, the spraying air pressure is 0.3MPa and the particle size of spraying droplets is 6 microns, uniformly spraying a layer of uniformly stirred inorganic nano material water dispersion on the upper surface of the single-layer meta-aramid raw paper by using a high-pressure air spray gun, and allowing the inorganic nano material to permeate and diffuse to the inner layer of the aramid paper under the high-pressure spraying action to obtain the aramid raw paper with the initial hybrid structure; wherein the meta-aramid base paper has a moisture content of 4.5 percent and a gram weight of 45.1g/m 2 55 parts of precipitated fibers, 45 parts of chopped fibers and 0.36g/cm of tightness in the paper 3 The inorganic nano material in the inorganic nano material water dispersion liquid is inorganic nano silicon dioxide, the particle size of the powder is 50nm, and the inorganic nano material accounts for 15 parts by mass in the dispersion liquid;
(2) carrying out vacuum suction on the surface, which is not sprayed with the inorganic nano material aqueous dispersion, of the aramid base paper with the initial hybrid structure obtained in the step (1) through a vacuum guide roller under the condition that the vacuum degree is-30 kPa, and further permeating and diffusing the inorganic nano material to the inner layer of the aramid paper layer under the vacuum suction effect, so that the aramid paper with the double-layer structure, wherein the upper layer is an inorganic nano material doped distribution layer, and the lower layer is a pure aramid paper layer, is obtained;
(3) under the conditions that the cold pressing temperature is 30 ℃ and the cold pressing pressure is 1.5MPa, the other gram weight is 49.8g/m 2 Carrying out cold pressing compounding on the single-layer meta-aramid base paper and the inorganic nano material spraying surface of the double-layer structure aramid paper obtained in the step (2) through a cold pressing roller to obtain a three-layer structure aramid paper with a compact structure and an inorganic nano material contained in the middle layer;
(4) and (3) drying, hot-pressing and rolling the aramid fiber paper containing the inorganic nano material aramid fiber three-layer structure obtained in the step (3) to obtain the three-layer structure inorganic nano material reinforced aramid fiber insulation paper of claim 1. Wherein the drying temperature is 150 ℃, the hot pressing temperature is 320 ℃, and the hot pressing pressure is 25 MPa.
The structural schematic diagram of the inorganic nano-material reinforced aramid insulation paper prepared in the embodiment is shown in fig. 1, the thickness is 98.2 microns, the quantitative content is 92.3g/m2, and the content of inorganic nano-silica in the paper is 2.4g/m 2 。
Example 2:
a preparation method of aramid fiber insulation paper reinforced by inorganic nano materials is shown in a process flow schematic diagram of figure 2, and comprises the following steps:
(1) under the conditions that the spraying hydraulic pressure is 0.15MPa, the spraying air pressure is 0.3MPa and the particle size of spraying droplets is 6 microns, uniformly spraying a layer of uniformly stirred inorganic nano material water dispersion on the upper surface of the single-layer meta-aramid raw paper by using a high-pressure air spray gun, and allowing the inorganic nano material to permeate and diffuse to the inner layer of the aramid paper under the high-pressure spraying action to obtain the aramid raw paper with the initial hybrid structure; wherein the meta-aramid base paper has a moisture content of 4.5 percent and a gram weight of 44.5g/m 2 50 portions of precipitated fiber, 50 portions of chopped fiber and 0.36g/cm tightness in the paper 3 The inorganic nano material in the inorganic nano material water dispersion liquid is inorganic nano alumina, the particle size of the powder is 40nm, and the inorganic nano material accounts for 13 parts by mass in the dispersion liquid;
(2) carrying out vacuum suction on the surface, which is not sprayed with the inorganic nano material aqueous dispersion, of the aramid base paper with the initial hybrid structure obtained in the step (1) through a vacuum guide roller under the condition that the vacuum degree is-30 kPa, and further permeating and diffusing the inorganic nano material to the inner layer of the aramid paper layer under the vacuum suction effect, so that the aramid paper with the double-layer structure, wherein the upper layer is an inorganic nano material doped distribution layer, and the lower layer is a pure aramid paper layer, is obtained;
(3) under the conditions that the cold pressing temperature is 30 ℃ and the cold pressing pressure is 1.5MPa, the other gram weight is 44.6g/m 2 The single-layer meta-aramid raw paper and the inorganic nano-material spraying surface of the double-layer structure aramid paper obtained in the step (2) are compounded through cold pressing of a cold pressing roller, and the three-layer structure aramid paper with a compact structure and an inorganic nano-material-containing middle layer is obtained;
(4) and (3) drying, hot-pressing and rolling the aramid fiber paper containing the inorganic nano material aramid fiber three-layer structure obtained in the step (3) to obtain the three-layer structure inorganic nano material reinforced aramid fiber insulation paper of claim 1. Wherein the drying temperature is 150 ℃, the hot pressing temperature is 320 ℃, and the hot pressing pressure is 25 MPa.
The structural schematic diagram of the inorganic nano-material reinforced aramid insulation paper prepared in the embodiment is shown in fig. 1, the thickness is 98.2 microns, the quantitative amount is 91.5g/m2, and the content of inorganic nano-silica in the paper is 2.3g/m 2 。
Comparative example 1:
the aramid fiber raw material with the same gram weight as that of the inorganic nano material reinforced aramid insulation paper in the example 1 is adopted, and the thick single-layer meta-aramid paper is prepared by beating, flow forming, squeezing, drying and hot rolling forming which are the same as those of the example 1, so that the comparative example 1 is obtained.
The results of comparing the gram weight, tensile strength, electrical strength, initial partial discharge voltage, and partial discharge capacity at rated voltage for the above examples 1, 2, and 1 are shown in the following table:
from the above-mentioned detection results, it can be seen that the tensile strength of the inorganic nano material reinforced aramid insulation paper prepared in examples 1 and 2 is slightly reduced compared with that of comparative example 1, but the reduction degree is not large and is basically at the same level, which indicates that the strength of the aramid insulation paper is not significantly affected by adding a proper amount of the inorganic nano material by a spraying method, and at the same time, the electrical breakdown strength of the inorganic nano material reinforced aramid insulation paper prepared in examples 1 and 2 is increased from 18.8MV/m of the pure aramid paper to more than 21.9MV/m, the initial partial discharge voltage is increased from 4.2kv to more than 5.7kv, and the partial discharge amount is reduced by more than 40%, which indicates that the electrical breakdown performance and the high-frequency pulse dielectric performance of the aramid paper can be significantly improved by spraying and doping modification of the inorganic nano material, and can be used for a track traction motor, Motor equipment such as a transformer, a wind power motor, a reactor, a new energy high-frequency high-voltage light motor and the like provides higher dielectric protection performance, and the purposes of prolonging the service life of the motor, reducing the maintenance cost and improving the production benefit are achieved.
In addition, in actual use, a proper amount of single-layer aramid base paper, such as two layers, four layers and the like, can be selected according to the required thickness and dielectric property of the aramid paper, and the high-performance aramid insulation paper doped with the inorganic nano material can be prepared by spraying the inorganic nano material between every two layers and then carrying out hot-press compounding. The similar spraying doping method is adopted to prepare more layers of the inorganic nano material reinforced aramid fiber insulating paper, and the method is also in the protection range of the patent.
The above embodiments are provided for illustrative purposes only and not for limiting the present invention, and those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention, and therefore all equivalent technical solutions should fall within the scope of the present invention, and the scope of the present invention should be defined by the claims.
Claims (15)
1. The aramid insulating paper reinforced by the inorganic nano material is characterized by comprising a plurality of aramid paper layers and an inorganic nano material doping distribution layer positioned between every two adjacent aramid paper layers; the inorganic nano material doping distribution layer is a deposition layer of inorganic nano material aqueous dispersion.
2. The aramid insulation paper as claimed in claim 1, wherein the content of the inorganic nano-material in the aramid insulation paper reinforced by the inorganic nano-material is 0.01-10 g/m 2 。
3. The aramid insulation paper as claimed in claim 2, wherein the aramid paper layer is a meta-aramid paper layer or a para-aramid paper layer.
4. The aramid insulation paper as claimed in claim 3, wherein the meta-aramid paper layer contains 40-70 parts of fibrids and 30-60 parts of chopped fibers; the para-aramid paper layer comprises 50-80 parts of fibrids and 20-50 parts of chopped fibers.
5. A method for preparing the inorganic nano material reinforced aramid insulating paper as claimed in any one of claims 1 to 4, wherein the preparation process comprises the following steps:
(1) uniformly spraying a layer of inorganic nano material water dispersion on the upper surface of the single-layer aramid raw paper to obtain aramid raw paper with an initial mixed structure;
(2) carrying out vacuum suction on the aramid raw paper with the initial hybrid structure obtained in the step (1) from the side which is not sprayed with the inorganic nano material aqueous dispersion to obtain aramid paper with a double-layer structure, wherein one layer is an inorganic nano material doped distribution layer, and the other layer is a pure aramid paper layer;
(3) carrying out cold pressing compounding on the other single-layer aramid base paper and the inorganic nano material spraying surface of the double-layer aramid paper obtained in the step (2) to obtain three-layer aramid paper with the middle layer containing the inorganic nano material;
(4) and (4) drying and hot-pressing the aramid fiber paper with the intermediate layer containing the inorganic nano material aramid fiber three-layer structure obtained in the step (3) to obtain the inorganic nano material reinforced aramid fiber insulation paper.
6. The preparation method of claim 5, wherein the grammage of the single-layer aramid base paper prepared in the preparation processes (1) and (3) is 10-180 g/m 2 。
7. The preparation method of claim 6, wherein the grammage of the single-layer aramid base paper prepared in the preparation processes (1) and (3) is 12-120 g/m 2 。
8. The preparation method of claim 5, wherein the tightness of the single-layer aramid base paper is 0.20-0.68 g/cm 3 。
9. The preparation method of claim 5, wherein the moisture content of the single-layer aramid base paper is 1.0-20.0%.
10. The preparation method according to claim 5, wherein the inorganic nanomaterial in the inorganic nanomaterial water dispersion is one or a combination of more than two of nano zinc oxide, nano silica, nano alumina, nano titania, nano silicon carbide, nano boron nitride and nano mica powder.
11. The method according to claim 10, wherein the particle size of the inorganic nanomaterial in the aqueous dispersion of inorganic nanomaterials is 10 to 100 nm.
12. The method according to claim 11, wherein the inorganic nanomaterial aqueous dispersion comprises 0.1 to 30 parts of inorganic nanomaterial and 70 to 99.9 parts of water.
13. The preparation method according to claim 5, wherein the spraying in the step (1) is performed by using a high-pressure air spray gun, the spraying hydraulic pressure of the high-pressure air spray gun is 0.01-1.0 MPa, the spraying air pressure is 0.1-5.0 MPa, and the particle size of the sprayed liquid drop is 2-10 μm.
14. The manufacturing method according to claim 5, wherein the vacuum suction in the step (2) is performed by using a vacuum guide roller with a vacuum degree of-0.1 to-100 kPa; a cold pressing roller is adopted during cold pressing compounding in the step (3), the cold pressing temperature is 0-50 ℃, and the cold pressing pressure is 0.2-30 MPa; the drying temperature in the drying process in the step (4) is 100-300 ℃; the hot pressing temperature is 250-400 ℃, and the hot pressing pressure is 5-50 MPa.
15. An application method of the aramid insulation paper reinforced by the inorganic nano material is characterized in that the aramid insulation paper reinforced by the inorganic nano material according to any one of claims 1 to 4 is applied to track traction motors, transformers, wind motors, reactors, new energy high-frequency high-voltage light motors and other motor and electrical equipment; the application thickness of the inorganic nano material reinforced aramid fiber insulating paper is 0.03-0.8 mm.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210474616.7A CN115045140A (en) | 2022-04-29 | 2022-04-29 | Aramid fiber insulating paper reinforced by inorganic nano material and preparation method and application thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210474616.7A CN115045140A (en) | 2022-04-29 | 2022-04-29 | Aramid fiber insulating paper reinforced by inorganic nano material and preparation method and application thereof |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN115045140A true CN115045140A (en) | 2022-09-13 |
Family
ID=83158125
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202210474616.7A Pending CN115045140A (en) | 2022-04-29 | 2022-04-29 | Aramid fiber insulating paper reinforced by inorganic nano material and preparation method and application thereof |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN115045140A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116892129A (en) * | 2023-09-11 | 2023-10-17 | 四川大学 | Corona-resistant N-level insulating paper for variable frequency motor and preparation method thereof |
Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106245411A (en) * | 2016-08-30 | 2016-12-21 | 烟台民士达特种纸业股份有限公司 | A kind of production method of meta-aramid fibers paper base material |
| JP2017025458A (en) * | 2015-07-28 | 2017-02-02 | 王子ホールディングス株式会社 | Method for manufacturing inorganic fiber sheet, fired body, and honeycomb filter |
| CN109468882A (en) * | 2018-10-18 | 2019-03-15 | 华南理工大学 | A kind of manufacturing method of gradient-structure nanometer aramid paper |
| CN110939008A (en) * | 2019-12-17 | 2020-03-31 | 株洲时代华先材料科技有限公司 | Method for manufacturing meta-aramid raw paper with high insulation performance |
| CN111304955A (en) * | 2020-02-20 | 2020-06-19 | 陕西科技大学 | Method for in-situ reinforcement of paper base material performance by aramid nano-fiber |
| CN111519473A (en) * | 2020-03-25 | 2020-08-11 | 株洲时代新材料科技股份有限公司 | High-dielectric-property composite aramid paper |
| CN112609493A (en) * | 2020-12-28 | 2021-04-06 | 山东聚芳新材料股份有限公司 | Composite papermaking nano reinforced aramid fiber paper and preparation method thereof |
| CN113293640A (en) * | 2021-06-28 | 2021-08-24 | 山东聚芳新材料股份有限公司 | Para-aramid nanofiber and high-performance carbon fiber composite paper and preparation method thereof |
-
2022
- 2022-04-29 CN CN202210474616.7A patent/CN115045140A/en active Pending
Patent Citations (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2017025458A (en) * | 2015-07-28 | 2017-02-02 | 王子ホールディングス株式会社 | Method for manufacturing inorganic fiber sheet, fired body, and honeycomb filter |
| CN106245411A (en) * | 2016-08-30 | 2016-12-21 | 烟台民士达特种纸业股份有限公司 | A kind of production method of meta-aramid fibers paper base material |
| CN109468882A (en) * | 2018-10-18 | 2019-03-15 | 华南理工大学 | A kind of manufacturing method of gradient-structure nanometer aramid paper |
| CN110939008A (en) * | 2019-12-17 | 2020-03-31 | 株洲时代华先材料科技有限公司 | Method for manufacturing meta-aramid raw paper with high insulation performance |
| CN111304955A (en) * | 2020-02-20 | 2020-06-19 | 陕西科技大学 | Method for in-situ reinforcement of paper base material performance by aramid nano-fiber |
| CN111519473A (en) * | 2020-03-25 | 2020-08-11 | 株洲时代新材料科技股份有限公司 | High-dielectric-property composite aramid paper |
| CN112746522A (en) * | 2020-03-25 | 2021-05-04 | 株洲时代新材料科技股份有限公司 | High-dielectric-property composite aramid paper |
| CN112609493A (en) * | 2020-12-28 | 2021-04-06 | 山东聚芳新材料股份有限公司 | Composite papermaking nano reinforced aramid fiber paper and preparation method thereof |
| CN113293640A (en) * | 2021-06-28 | 2021-08-24 | 山东聚芳新材料股份有限公司 | Para-aramid nanofiber and high-performance carbon fiber composite paper and preparation method thereof |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116892129A (en) * | 2023-09-11 | 2023-10-17 | 四川大学 | Corona-resistant N-level insulating paper for variable frequency motor and preparation method thereof |
| CN116892129B (en) * | 2023-09-11 | 2023-11-14 | 四川大学 | Corona-resistant N-level insulating paper for variable frequency motor and preparation method thereof |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US10011951B2 (en) | Method for producing meta-aramid fiber paper-based material | |
| CN109265879B (en) | High-orientation-arrangement core-shell-structure fiber polyvinylidene fluoride-based composite medium and preparation method thereof | |
| CN111546722B (en) | Reinforced high-thermal-conductivity mica tape and preparation method thereof | |
| CN111732746B (en) | Aramid nanofiber based laminated composite film, preparation method thereof and recycling method thereof | |
| CN111900418B (en) | Preparation method of carbon paper precursor for gas diffusion layer of fuel cell | |
| CN111576079B (en) | Conductive carbon paper and preparation method thereof | |
| CN111519473A (en) | High-dielectric-property composite aramid paper | |
| KR101392227B1 (en) | Carbon fiber web comprising polymer nanofiber | |
| CN112663382B (en) | High-mechanical-strength aramid fiber insulation paper and preparation method and application thereof | |
| CN115045140A (en) | Aramid fiber insulating paper reinforced by inorganic nano material and preparation method and application thereof | |
| Xie et al. | Toward high-performance nanofibrillated cellulose/aramid fibrid paper-based composites via polyethyleneimine-assisted decoration of silica nanoparticle onto aramid fibrid | |
| CN105568774A (en) | High-performance oil-immersed insulation paper and preparation method and application thereof | |
| CN111549567A (en) | Modified preparation method of high-thermal-conductivity mica paper | |
| CN105603802A (en) | Method for preparing high-smoothness poly-m-phenyleneisophthalamide paper for insulation | |
| CN114214867A (en) | Corona-resistant aramid/mica insulation paper and preparation method thereof | |
| CN111560793A (en) | Little-glue mica paper reinforced by fibers | |
| CN107354808A (en) | Aramid fiber/polyimide fiber composite-insulating paper of excellent performance and preparation method thereof is worn in a kind of resistance | |
| CN111088715A (en) | Preparation method of high-temperature-resistant insulating paper | |
| CN110670392B (en) | Processing technology for producing refractory plate by modified kraft paper | |
| CN110247065B (en) | Low-cost continuous industrial production process of gas diffusion layer of fuel cell | |
| CN111856227A (en) | Method for improving thermal aging resistance of converter transformer oil paper insulation and testing method | |
| CN115198567B (en) | High-performance aramid laminate and preparation method and application thereof | |
| CN110746746A (en) | Medium-density aramid fiber paper laminated board and preparation method thereof | |
| CN113584948B (en) | Preparation method of low-dielectric-constant insulating paper based on nano MgO modification | |
| CN107740204A (en) | A kind of basalt fibre for cable insulation and preparation method thereof |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| RJ01 | Rejection of invention patent application after publication |
Application publication date: 20220913 |