CN116875361A - Insulating cooling liquid for alpine region and preparation method thereof - Google Patents
Insulating cooling liquid for alpine region and preparation method thereof Download PDFInfo
- Publication number
- CN116875361A CN116875361A CN202310652822.7A CN202310652822A CN116875361A CN 116875361 A CN116875361 A CN 116875361A CN 202310652822 A CN202310652822 A CN 202310652822A CN 116875361 A CN116875361 A CN 116875361A
- Authority
- CN
- China
- Prior art keywords
- parts
- glycerol
- polyoxyethylene ether
- dodecanal
- dodecyl
- 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
- 239000000110 cooling liquid Substances 0.000 title claims abstract description 14
- 238000002360 preparation method Methods 0.000 title claims description 6
- 239000003921 oil Substances 0.000 claims abstract description 21
- CYEJMVLDXAUOPN-UHFFFAOYSA-N 2-dodecylphenol Chemical compound CCCCCCCCCCCCC1=CC=CC=C1O CYEJMVLDXAUOPN-UHFFFAOYSA-N 0.000 claims abstract description 17
- 229920000056 polyoxyethylene ether Polymers 0.000 claims abstract description 17
- 229940051841 polyoxyethylene ether Drugs 0.000 claims abstract description 17
- -1 dodecanal glycerol Chemical compound 0.000 claims abstract description 16
- 239000013530 defoamer Substances 0.000 claims description 15
- 125000003354 benzotriazolyl group Chemical group N1N=NC2=C1C=CC=C2* 0.000 claims description 14
- 239000003963 antioxidant agent Substances 0.000 claims description 11
- 230000003078 antioxidant effect Effects 0.000 claims description 11
- 239000002826 coolant Substances 0.000 claims description 11
- 230000007797 corrosion Effects 0.000 claims description 11
- 238000005260 corrosion Methods 0.000 claims description 11
- 239000003112 inhibitor Substances 0.000 claims description 11
- 238000010438 heat treatment Methods 0.000 claims description 9
- 239000004034 viscosity adjusting agent Substances 0.000 claims description 9
- 239000002184 metal Substances 0.000 claims description 8
- DURPTKYDGMDSBL-UHFFFAOYSA-N 1-butoxybutane Chemical compound CCCCOCCCC DURPTKYDGMDSBL-UHFFFAOYSA-N 0.000 claims description 7
- 239000004721 Polyphenylene oxide Substances 0.000 claims description 7
- 229920000570 polyether Polymers 0.000 claims description 7
- 238000003756 stirring Methods 0.000 claims description 7
- 229920002554 vinyl polymer Polymers 0.000 claims description 7
- 238000000034 method Methods 0.000 claims description 4
- 238000001816 cooling Methods 0.000 claims description 2
- 238000002156 mixing Methods 0.000 claims description 2
- HISQRFFCSVGSGI-UHFFFAOYSA-N pentadecane-1,2,3-triol Chemical compound CCCCCCCCCCCCC(O)C(O)CO HISQRFFCSVGSGI-UHFFFAOYSA-N 0.000 abstract description 6
- 239000002199 base oil Substances 0.000 abstract description 5
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical group [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 abstract description 4
- 238000013329 compounding Methods 0.000 abstract description 2
- 238000010907 mechanical stirring Methods 0.000 description 5
- 239000000203 mixture Substances 0.000 description 5
- 239000002518 antifoaming agent Substances 0.000 description 3
- 239000000126 substance Substances 0.000 description 3
- 125000000217 alkyl group Chemical group 0.000 description 2
- 230000008901 benefit Effects 0.000 description 2
- 230000000052 comparative effect Effects 0.000 description 2
- 230000007547 defect Effects 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000002508 compound effect Effects 0.000 description 1
- 238000009413 insulation Methods 0.000 description 1
- 230000007704 transition Effects 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
- C10M169/00—Lubricating compositions characterised by containing as components a mixture of at least two types of ingredient selected from base-materials, thickeners or additives, covered by the preceding groups, each of these compounds being essential
- C10M169/04—Mixtures of base-materials and additives
- C10M169/044—Mixtures of base-materials and additives the additives being a mixture of non-macromolecular and macromolecular compounds
-
- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
- C09K5/00—Heat-transfer, heat-exchange or heat-storage materials, e.g. refrigerants; Materials for the production of heat or cold by chemical reactions other than by combustion
- C09K5/08—Materials not undergoing a change of physical state when used
- C09K5/10—Liquid materials
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
- C10M177/00—Special methods of preparation of lubricating compositions; Chemical modification by after-treatment of components or of the whole of a lubricating composition, not covered by other classes
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
- C10M2207/00—Organic non-macromolecular hydrocarbon compounds containing hydrogen, carbon and oxygen as ingredients in lubricant compositions
- C10M2207/04—Ethers; Acetals; Ortho-esters; Ortho-carbonates
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
- C10M2209/00—Organic macromolecular compounds containing oxygen as ingredients in lubricant compositions
- C10M2209/10—Macromolecular compoundss obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds
- C10M2209/103—Polyethers, i.e. containing di- or higher polyoxyalkylene groups
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
- C10M2209/00—Organic macromolecular compounds containing oxygen as ingredients in lubricant compositions
- C10M2209/10—Macromolecular compoundss obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds
- C10M2209/103—Polyethers, i.e. containing di- or higher polyoxyalkylene groups
- C10M2209/104—Polyethers, i.e. containing di- or higher polyoxyalkylene groups of alkylene oxides containing two carbon atoms only
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
- C10M2215/00—Organic non-macromolecular compounds containing nitrogen as ingredients in lubricant compositions
- C10M2215/22—Heterocyclic nitrogen compounds
- C10M2215/223—Five-membered rings containing nitrogen and carbon only
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10N—INDEXING SCHEME ASSOCIATED WITH SUBCLASS C10M RELATING TO LUBRICATING COMPOSITIONS
- C10N2030/00—Specified physical or chemical properties which is improved by the additive characterising the lubricating composition, e.g. multifunctional additives
- C10N2030/08—Resistance to extreme temperature
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10N—INDEXING SCHEME ASSOCIATED WITH SUBCLASS C10M RELATING TO LUBRICATING COMPOSITIONS
- C10N2040/00—Specified use or application for which the lubricating composition is intended
- C10N2040/14—Electric or magnetic purposes
- C10N2040/16—Dielectric; Insulating oil or insulators
Landscapes
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Organic Chemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Combustion & Propulsion (AREA)
- Thermal Sciences (AREA)
- Materials Engineering (AREA)
- Lubricants (AREA)
Abstract
The invention discloses an insulating cooling liquid for alpine regions, which comprises the following components in parts by weight: 55-65 parts of No. 25 transformer oil, 20-28 parts of dodecanal glycerol, and 8-14 parts of dodecylphenol polyoxyethylene ether. According to the invention, the No. 25 transformer oil is compounded with the dodecanal glycerol, so that the three-dimensional twisted molecular structure of the dodecanal glycerol is fully utilized, the viscosity of the base oil at low temperature can be obviously reduced, and the fluidity of the base oil is enhanced. And then dodecyl phenol polyoxyethylene ether is added, the hydrophilic and lipophilic groups of the dodecyl phenol polyoxyethylene ether and the hydrophilic groups of the dodecyl glycerol are fully developed, the long carbon chain of the No. 25 transformer oil and the lipophilic groups of the dodecyl glycerol also form intermolecular forces, and the intermolecular forces formed by compounding the long carbon chain of the dodecyl phenol polyoxyethylene ether and the hydrophilic groups of the dodecyl glycerol can effectively enhance the stability of the three-component system, so that the low-temperature flowing property of the dodecyl phenol polyoxyethylene ether is better, and the pour point value is lower.
Description
Technical Field
The invention relates to the technical field of insulating cooling liquid, in particular to an insulating cooling liquid for alpine regions and a preparation method thereof.
Background
Currently, reliable operation of the converter requires adequate dielectric insulation and dissipation of heat released during voltage transitions. Because the cooling liquid directly contacts the electronic device, high requirements are placed on the insulativity, flowability, volatility, chemical stability and the like of the cooling liquid.
The existing insulating cooling liquid has the defects of poor low-temperature flow performance and higher pour point value, and is not suitable for working in alpine regions.
Disclosure of Invention
In order to overcome the defects in the prior art, the invention provides the insulating cooling liquid and the method for the alpine region, which have the advantages of better low-temperature flow property, lower pour point value and the like.
In order to achieve the above purpose, the present invention adopts the following technical scheme:
the insulating cooling liquid for the alpine region comprises the following components in parts by weight: 55-65 parts of No. 25 transformer oil, 20-28 parts of dodecanal glycerol, and 8-14 parts of dodecylphenol polyoxyethylene ether. According to the invention, the No. 25 transformer oil is adopted, the 3D structure is flat, and the 3D structure is compounded with the dodecanal glycerol, so that the three-dimensional twisted molecular structure of the dodecanal glycerol is fully utilized, the viscosity of the base oil (No. 25 transformer oil) at low temperature can be obviously reduced, and the fluidity of the base oil is enhanced. And then dodecyl phenol polyoxyethylene ether is added, the hydrophilic and lipophilic groups of the dodecyl phenol polyoxyethylene ether and the hydrophilic groups of the dodecyl glycerol are fully developed, the long carbon chain of the No. 25 transformer oil and the lipophilic groups of the dodecyl glycerol also form intermolecular forces, and the intermolecular forces formed by compounding the long carbon chain of the dodecyl phenol polyoxyethylene ether and the hydrophilic groups of the dodecyl glycerol can effectively enhance the stability of the three-component system, so that the low-temperature flowing property of the dodecyl phenol polyoxyethylene ether is better, and the pour point value is lower.
Preferably, the insulating coolant for alpine regions of the present invention further comprises 0.5 to 0.7 parts of an antioxidant.
Preferably, the antioxidant is a benzotriazole derivative.
Preferably, the insulating coolant for alpine regions of the present invention further comprises 0.2 to 0.4 parts of a metallic corrosion inhibitor.
Preferably, the metal corrosion inhibitor is a benzotriazole derivative.
Preferably, the insulating coolant for alpine regions of the present invention further comprises 0.8-1.0 parts of a viscosity modifier.
Preferably, the viscosity modifier is polyvinyl n-butyl ether.
Preferably, the insulating cooling liquid for the alpine region further comprises 0.5-0.7 part of defoaming agent, wherein the defoaming agent is polyether defoaming agent.
The invention also discloses a preparation method of the insulating cooling liquid for the alpine region, which comprises the following steps:
1) Adding No. 25 transformer oil into the reaction equipment, stirring and heating;
2) Then adding dodecanal glycerol, and fully stirring to uniformly mix the two;
3) Finally, adding the dodecylphenol polyoxyethylene ether, the antioxidant, the metal corrosion inhibitor, the viscosity regulator and the defoamer, fully and uniformly mixing, and naturally cooling to normal temperature.
Preferably, the temperature after heating in step 1) is maintained at 40.+ -. 2 ℃.
The beneficial effects of the invention are as follows: (1) The invention can effectively enhance the stability of a three-component system, so that the low-temperature flow property of the three-component system is better, and the pour point value is lower; (2) The product of long-chain alkyl and oil are better in compatibility than short-chain alkyl, so that the compound effect can be better exerted; (3) The unexpected benefit of the invention is that the molecular structure characteristics of the dodecanal glycerol can be utilized to obviously reduce the viscosity of the base oil and obviously improve the low-temperature fluidity.
Drawings
FIG. 1 is a chemical structural formula of dodecanal glycerol according to the present invention.
Detailed Description
The invention is further described below with reference to the drawings and specific embodiments. The chemical structural formula of the specific dodecanal glycerol is shown in figure 1.
Example 1
Adding 65 parts of No. 25 transformer oil into a reaction kettle, starting mechanical stirring and jacket heating, controlling the temperature of the transformer oil at 40 ℃, adding 28 parts of dodecanal glycerol, and fully stirring to uniformly mix the two; finally adding 14 parts of dodecylphenol polyoxyethylene ether and an antioxidant: 0.5 part of benzotriazole derivative, metal corrosion inhibitor: 0.2 part of benzotriazole derivative, viscosity modifier: 0.8 part of polyvinyl n-butyl ether and 0.5 part of defoamer, namely polyether defoamer, are fully and uniformly mixed and naturally cooled to normal temperature.
Example 2
60 parts of No. 25 transformer oil is added into a reaction kettle, mechanical stirring and jacket heating are started, the temperature of the transformer oil is controlled at 38 ℃, and then 24 parts of dodecanal glycerol is added into the reaction kettle, and the mixture is fully stirred to be uniformly mixed; finally, 11 parts of dodecylphenol polyoxyethylene ether and an antioxidant are added: 0.7 parts of benzotriazole derivative, metal corrosion inhibitor: 0.4 parts of benzotriazole derivative, viscosity modifier: 1.0 part of polyvinyl n-butyl ether and 0.7 part of defoamer, namely polyether defoamer, are fully and uniformly mixed and naturally cooled to normal temperature.
Example 3
Adding 55 parts of No. 25 transformer oil into a reaction kettle, starting mechanical stirring and jacket heating, controlling the temperature of the transformer oil at 42 ℃, adding 20 parts of dodecanal glycerol, and fully stirring to uniformly mix the two; finally adding 8 parts of dodecylphenol polyoxyethylene ether and an antioxidant: 0.6 part of benzotriazole derivative, metal corrosion inhibitor: 0.3 parts of benzotriazole derivative, viscosity modifier: 0.9 part of polyvinyl n-butyl ether and 0.6 part of defoamer, namely polyether defoamer, are fully and uniformly mixed and naturally cooled to normal temperature.
Comparative example 1
Adding 66 parts of No. 25 transformer oil into a reaction kettle, starting mechanical stirring and jacket heating, controlling the temperature of the transformer oil at 37 ℃, adding 29 parts of dodecanal glycerol, and fully stirring to uniformly mix the two; finally adding an antioxidant: 0.4 parts of benzotriazole derivative, metal corrosion inhibitor: 0.5 part of benzotriazole derivative, viscosity modifier: 0.7 part of polyvinyl n-butyl ether and 0.8 part of defoamer, namely polyether defoamer, are fully and uniformly mixed and naturally cooled to normal temperature.
Comparative example 2
54 parts of No. 25 transformer oil is added into a reaction kettle, mechanical stirring and jacket heating are started, the temperature of the transformer oil is controlled at 43 ℃, 13 parts of dodecylphenol polyoxyethylene ether and an antioxidant are added: 0.4 parts of benzotriazole derivative, metal corrosion inhibitor: 0.1 part of benzotriazole derivative, viscosity modifier: 1.1 parts of polyvinyl n-butyl ether and 0.4 part of defoamer, namely polyether defoamer, are fully and uniformly mixed and naturally cooled to normal temperature.
Experimental data for the product made according to the invention are given in the following table:
as can be seen from the above test data, the product of the present invention prepared according to the predetermined range of the ratio and process has a pour point of only-70 ℃ to-69 ℃ and a viscosity of only 19.4-20mm at-30 DEG C 2 S; for the products with the proportion and the temperature exceeding the range specified by the invention in the preparation process, the pour point reaches-52 ℃ and-26 ℃, and the viscosity reaches 80 and 180mm at the temperature of-30 DEG C 2 And/s, which is far higher than the pour point and viscosity values of the products prepared by the process according to the invention in the predetermined range.
The foregoing description is only of the preferred embodiments of the present invention, and is not intended to limit the scope of the invention, and all equivalent changes made in the description and drawings of the invention, directly or indirectly, are included in the scope of the invention.
Claims (10)
1. The insulating cooling liquid for the alpine region is characterized by comprising the following components in parts by weight: 55-65 parts of No. 25 transformer oil, 20-28 parts of dodecanal glycerol, and 8-14 parts of dodecylphenol polyoxyethylene ether.
2. The insulating coolant for alpine regions according to claim 1, further comprising 0.5-0.7 parts of an antioxidant.
3. An insulating coolant for alpine regions according to claim 2, wherein the antioxidant is a benzotriazole derivative.
4. The insulating coolant for alpine regions according to claim 1, further comprising 0.2-0.4 parts of a metallic corrosion inhibitor.
5. An insulating coolant for alpine regions according to claim 4, wherein the metallic corrosion inhibitor is a benzotriazole derivative.
6. The insulating coolant for alpine regions according to claim 1, further comprising 0.8-1.0 parts of viscosity modifier.
7. The insulating coolant for alpine regions according to claim 6, wherein the viscosity modifier is polyvinyl n-butyl ether.
8. The insulating coolant for alpine regions according to claim 1 or 2 or 3 or 4 or 5 or 6 or 7, further comprising 0.5-0.7 parts of defoamer, wherein the defoamer is polyether defoamer.
9. The preparation method of the insulating cooling liquid for the alpine region is characterized by comprising the following steps of:
1) Adding No. 25 transformer oil into the reaction equipment, stirring and heating;
2) Then adding dodecanal glycerol, and fully stirring to uniformly mix the two;
3) Finally, adding the dodecylphenol polyoxyethylene ether, the antioxidant, the metal corrosion inhibitor, the viscosity regulator and the defoamer, fully and uniformly mixing, and naturally cooling to normal temperature.
10. The method for preparing an insulating coolant for alpine regions according to claim 9, wherein the temperature after heating in step 1) is maintained at 40±2 ℃.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
CN202310652822.7A CN116875361A (en) | 2023-06-02 | 2023-06-02 | Insulating cooling liquid for alpine region and preparation method thereof |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
CN202310652822.7A CN116875361A (en) | 2023-06-02 | 2023-06-02 | Insulating cooling liquid for alpine region and preparation method thereof |
Publications (1)
Publication Number | Publication Date |
---|---|
CN116875361A true CN116875361A (en) | 2023-10-13 |
Family
ID=88270495
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
CN202310652822.7A Pending CN116875361A (en) | 2023-06-02 | 2023-06-02 | Insulating cooling liquid for alpine region and preparation method thereof |
Country Status (1)
Country | Link |
---|---|
CN (1) | CN116875361A (en) |
-
2023
- 2023-06-02 CN CN202310652822.7A patent/CN116875361A/en active Pending
Similar Documents
Publication | Publication Date | Title |
---|---|---|
CN102489049B (en) | Mineral oil type antifoaming agent and preparation method thereof | |
CN113861948B (en) | Cooling liquid and preparation method and application thereof | |
CN105861119B (en) | Low condensation point transformer oil of a kind of high-flash and preparation method thereof | |
EP3428930B1 (en) | Insulating liquid and electrical device for connection to a high-voltage grid | |
CN100590170C (en) | Automobile engine cooling liquid and its preparing process | |
CN111621266A (en) | Cooling liquid for electric automobile and preparation process thereof | |
CN101544919B (en) | Alcohol base gasoline solubilizer and preparation method thereof | |
CN116875361A (en) | Insulating cooling liquid for alpine region and preparation method thereof | |
CN111548774A (en) | Cooling liquid for plug-in hybrid electric vehicle and preparation process thereof | |
CN101665734B (en) | Oil antistatic agent and preparation method thereof | |
CN102260571B (en) | Novel aviation base oil | |
CN112521914B (en) | Heat management liquid and preparation method thereof | |
CN113604269B (en) | Preparation method of nano-magnesia modified palm insulating oil with high volume resistivity | |
WO2022089534A1 (en) | Method for preparing synthetic-organic-ester-type base oil and use thereof | |
CN111592864A (en) | High-boiling-point cooling liquid | |
CN112940692A (en) | Thermal management system fluid composition | |
CN112851915A (en) | Preparation method of waterborne organic silicon modified aliphatic polyamine epoxy curing agent | |
CN115820220B (en) | Anti-freezing cooling liquid for fuel cell and preparation method thereof | |
CN114464930B (en) | New energy automobile power battery cooling liquid, preparation method and application | |
CN115786021B (en) | Synthetic ester insulating oil and preparation method thereof | |
CN117143571B (en) | Battery cooling liquid, preparation method thereof and immersed energy storage battery | |
CN116948734A (en) | Bio-based capacitor insulating oil and preparation method thereof | |
CN109432829A (en) | One kind special-purpose polychloroethylene defoaming agent and preparation method thereof used in terminator soda bath | |
CN117050804A (en) | High-temperature furnace top lubricating grease and preparation method thereof | |
CN117448068B (en) | Brake fluid for severe cold areas 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 |