CN110980717A - Method for preparing graphene oxide by using vermicular graphite - Google Patents
Method for preparing graphene oxide by using vermicular graphite Download PDFInfo
- Publication number
- CN110980717A CN110980717A CN201911037483.1A CN201911037483A CN110980717A CN 110980717 A CN110980717 A CN 110980717A CN 201911037483 A CN201911037483 A CN 201911037483A CN 110980717 A CN110980717 A CN 110980717A
- Authority
- CN
- China
- Prior art keywords
- mixed solution
- temperature
- prepared
- filter cake
- solution prepared
- 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.)
- Withdrawn
Links
Images
Classifications
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B32/00—Carbon; Compounds thereof
- C01B32/15—Nano-sized carbon materials
- C01B32/182—Graphene
- C01B32/198—Graphene oxide
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B2204/00—Structure or properties of graphene
- C01B2204/04—Specific amount of layers or specific thickness
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B2204/00—Structure or properties of graphene
- C01B2204/20—Graphene characterized by its properties
- C01B2204/32—Size or surface area
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2004/00—Particle morphology
- C01P2004/01—Particle morphology depicted by an image
- C01P2004/03—Particle morphology depicted by an image obtained by SEM
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2004/00—Particle morphology
- C01P2004/01—Particle morphology depicted by an image
- C01P2004/04—Particle morphology depicted by an image obtained by TEM, STEM, STM or AFM
Abstract
A method for preparing graphene oxide by using vermicular graphite comprises the following steps: 1: crushing a plurality of 600 times of worm graphite by using a wall breaking machine into worm graphite powder; 2: 0.4-0.5g of sodium nitrate is put into 60-63ml of concentrated sulfuric acid, and the mixture is stirred in an ice water bath for 1 hour and dispersed; 3: putting 1g of graphite powder into a concentrated sulfuric acid-sodium nitrate mixed solution, putting 2-3g of potassium permanganate, and stirring at 9-10 ℃ for 3 hours to prepare a mixed solution; 4: placing the mixed solution in an oil bath kettle at 35 ℃ and stirring for 2 hours; 5: adding 180ml of deionized water with the temperature of 80 ℃ into the mixed solution, raising the temperature of the mixed solution to 95 ℃, and keeping the temperature for 0.5 hour; 6: adding 10ml of hydrogen peroxide into the mixed solution; 7: filtering the mixed solution, washing with deionized water to obtain a filter cake, and performing ultrasonic and centrifugal treatment; preparing graphene powder after freeze drying; the method has the advantages of high oxidation efficiency and simple process, and is suitable for industrial production.
Description
Technical Field
The invention relates to the technical field of graphene manufacturing, in particular to a method for preparing graphene oxide by using vermicular graphite.
Background
Graphene is a transparent material with a two-dimensional network structure of a single atomic layer developed in the last decade, and has good electrical conductivity, thermal conductivity and light transmittance, and the mechanical strength of the material is better than that of other existing materials; since the graphene lamella is obtained from experiments for the first time in 2004, the application of the graphene lamella in biology, medicine, photoelectric materials, semiconductors and conductors is developed unprecedentedly, and the graphene has excellent performance, so the graphene lamella is expected to be the most important novel material in the 21 st century; at present, methods for preparing graphene include a mechanical exfoliation method, a vapor deposition method, an epitaxial growth method, and a redox method; among these methods, the redox method has advantages of simple preparation process and low production cost, and is considered to be the most suitable method for industrial production; the graphene prepared by the currently common Hummers method mostly uses graphite micro powder (the particle size is less than 43 um) as a raw material, and large flake graphite as a raw material to prepare graphite oxide, so that the oxidation efficiency is low, and the stripping degree of the graphite oxide is poor.
Disclosure of Invention
The invention aims to prepare large graphene oxide with high oxidation degree by using vermicular graphite as a raw material and adopting an improved Hummers method, so as to solve the problems of high difficulty and low oxidation efficiency in preparing graphene oxide from large-scale graphite.
The technical scheme of the invention is as follows: a method for preparing graphene oxide by using vermicular graphite comprises the following steps:
step 1: crushing a plurality of 600 times of worm graphite by using a wall breaking machine into worm graphite powder;
step 2: 0.4-0.5g of sodium nitrate is put into 60-63ml of concentrated sulfuric acid, and the mixture is stirred in an ice water bath for 1 hour to be dispersed and turbid;
and step 3: 1g of the graphite powder prepared in the step 1 is put into the concentrated sulfuric acid-sodium nitrate mixed solution prepared in the step 2, 2-3g of potassium permanganate is slowly put into the mixed solution, the temperature is controlled to be 9-10 ℃ in an ice water bath, and the mixed solution is prepared after stirring for 3 hours;
and 4, step 4: placing the mixed solution prepared in the step 3 in an oil bath kettle at the temperature of 35 ℃ and stirring for 2 hours;
and 5: adding 180ml of deionized water with the temperature of 80 ℃ into the mixed solution prepared in the step 4, raising the temperature of the mixed solution to 95 ℃, and keeping the temperature for 0.5 hour;
step 6: adding 10ml of hydrogen peroxide into the mixed solution prepared in the step 5;
and 7: filtering the mixed solution prepared in the step 6, and washing with deionized water to prepare a filter cake;
and 8: taking the filter cake obtained in the step 7 down, and treating the filter cake with ultrasonic waves;
and step 9: treating the filter cake prepared in the step 8 by using a centrifugal machine, separating acid liquor, and reserving solid;
step 10: and (4) freeze-drying the solid obtained in the step (9) to obtain powder.
As a preferred technical scheme, a method for preparing graphene oxide by using vermicular graphite comprises the following steps:
step 1: crushing a plurality of 600 times of worm graphite by using a wall breaking machine into worm graphite powder;
step 2: 0.4g of sodium nitrate is put into 60ml of concentrated sulfuric acid, and the mixture is stirred in an ice water bath for 1 hour to be dispersed and turbid;
and step 3: 1g of the graphite powder prepared in the step 1 is put into the concentrated sulfuric acid-sodium nitrate mixed solution prepared in the step 2, 2g of potassium permanganate is slowly put into the mixed solution, the temperature is controlled to be 9-10 ℃ in an ice water bath, and the mixed solution is prepared after stirring for 3 hours;
and 4, step 4: placing the mixed solution prepared in the step 3 in an oil bath kettle at the temperature of 35 ℃ and stirring for 2 hours;
and 5: adding 180ml of deionized water with the temperature of 80 ℃ into the mixed solution prepared in the step 4, raising the temperature of the mixed solution to 95 ℃, and keeping the temperature for 0.5 hour;
step 6: adding 10ml of hydrogen peroxide into the mixed solution prepared in the step 5;
and 7: filtering the mixed solution prepared in the step 6, and washing with deionized water to prepare a filter cake;
and 8: taking the filter cake obtained in the step 7 down, and treating the filter cake with ultrasonic waves;
and step 9: treating the filter cake prepared in the step 8 by using a centrifugal machine, separating acid liquor, and reserving solid;
step 10: and (4) freeze-drying the solid obtained in the step (9) to obtain powder.
As a preferred technical scheme, a method for preparing graphene oxide by using vermicular graphite comprises the following steps:
step 1: crushing a plurality of 600 times of worm graphite by using a wall breaking machine into worm graphite powder;
step 2: 0.5g of sodium nitrate is put into 63ml of concentrated sulfuric acid, and the mixture is stirred in an ice water bath for 1 hour to be dispersed and turbid;
and step 3: 1g of the graphite powder prepared in the step 1 is put into the concentrated sulfuric acid-sodium nitrate mixed solution prepared in the step 2, and then 3g of potassium permanganate is slowly put into the mixed solution, the temperature is controlled to be 9-10 ℃ in an ice water bath, and the mixed solution is prepared after stirring for 3 hours;
and 4, step 4: placing the mixed solution prepared in the step 3 in an oil bath kettle at the temperature of 35 ℃ and stirring for 2 hours;
and 5: adding 180ml of deionized water with the temperature of 80 ℃ into the mixed solution prepared in the step 4, raising the temperature of the mixed solution to 95 ℃, and keeping the temperature for 0.5 hour;
step 6: adding 10ml of hydrogen peroxide into the mixed solution prepared in the step 5;
and 7: filtering the mixed solution prepared in the step 6, and washing with deionized water to prepare a filter cake;
and 8: taking the filter cake obtained in the step 7 down, and treating the filter cake with ultrasonic waves;
and step 9: treating the filter cake prepared in the step 8 by using a centrifugal machine, separating acid liquor, and reserving solid;
step 10: and (4) freeze-drying the solid obtained in the step (9) to obtain powder.
The invention has the beneficial effects that: compared with the prior art, the method has the advantages that 1, the crushed worm graphite is adopted, and the graphene oxide with large sheet diameter can be prepared from raw materials with larger particle diameter; 2. the prepared graphene oxide is in a thin yarn shape under an electron microscope, has high oxidation degree, contains functional groups such as-OH, -COOH, -CO, -CHOCH and the like, and has strong hydrophilicity; 3. the distance between the worm graphite layers is larger than that of the flake graphite, so that the contact area of the graphite sheet layer and an oxidant in the oxidation process is increased, and the problems of high difficulty and low oxidation efficiency in preparation of graphene oxide by using large-flake graphite are solved; 4. the method has simple process, and can provide a new way for the industrial production of the graphene oxide; as can be seen from AFM detection, the thickness of the graphene can be about 0.5-1.0 nm.
Drawings
Fig. 1 is an Atomic Force Microscope (AFM) examination of graphene oxide prepared according to the present invention.
Fig. 2 is an electron microscopy (SEM) examination of graphene oxide prepared according to the present invention.
Detailed Description
The following describes the embodiments of the present invention in detail with reference to fig. 1 and 2.
Example 1: a method for preparing graphene oxide by using vermicular graphite is characterized by comprising the following steps:
step 1: crushing a plurality of 600 times of worm graphite by a wall breaking machine into worm graphite powder.
Step 2: 0.4g of sodium nitrate was put into 60ml of concentrated sulfuric acid, and the mixture was stirred in an ice-water bath for 1 hour to disperse and become cloudy.
And step 3: and (3) putting 1g of the graphite powder prepared in the step (1) into the concentrated sulfuric acid-sodium nitrate mixed solution prepared in the step (2), slowly putting 2g of potassium permanganate, controlling the temperature to be 9-10 ℃ in an ice water bath, and stirring for 3 hours to prepare a mixed solution.
And 4, step 4: the mixed solution prepared in step 3 was stirred in an oil bath pan at 35 ℃ for 2 hours.
And 5: 180ml of deionized water having a temperature of 80 ℃ was added to the mixed solution obtained in step 4, and the temperature of the mixed solution was raised to 95 ℃ for 0.5 hour.
Step 6: and (5) adding 10ml of hydrogen peroxide into the mixed solution prepared in the step (5).
And 7: and (4) filtering the mixed solution prepared in the step (6), and washing with deionized water to prepare a filter cake.
And 8: the filter cake obtained in step 7 was removed and treated with ultrasound.
The sonication is intended to open the lamella gap.
And step 9: and (4) treating the filter cake prepared in the step (8) by using a centrifugal machine, separating acid liquor, and keeping solid.
Step 10: and (4) freeze-drying the solid obtained in the step (9) to obtain powder.
As shown in fig. 1, the effect obtained by detecting graphene oxide under an Atomic Force Microscope (AFM) is shown, and the thickness of the graphene is 6.0 nm.
As shown in fig. 2, the effect obtained by scanning graphene oxide with an electron microscope (SEM) is shown.
Example 2: a method for preparing graphene oxide by using vermicular graphite comprises the following steps:
step 1: crushing a plurality of 600 times of worm graphite by a wall breaking machine into worm graphite powder.
Step 2: 0.5g of sodium nitrate was put into 63ml of concentrated sulfuric acid, and the mixture was stirred in an ice-water bath for 1 hour to disperse and become cloudy.
And step 3: and (3) putting 1g of the graphite powder prepared in the step (1) into the concentrated sulfuric acid-sodium nitrate mixed solution prepared in the step (2), slowly putting 3g of potassium permanganate, controlling the temperature to be 9-10 ℃ in an ice water bath, and stirring for 3 hours to prepare a mixed solution.
And 4, step 4: the mixed solution prepared in step 3 was stirred in an oil bath pan at 35 ℃ for 2 hours.
And 5: 180ml of deionized water having a temperature of 80 ℃ was added to the mixed solution obtained in step 4, and the temperature of the mixed solution was raised to 95 ℃ for 0.5 hour.
Step 6: and (5) adding 10ml of hydrogen peroxide into the mixed solution prepared in the step (5).
And 7: and (4) filtering the mixed solution prepared in the step (6), and washing with deionized water to prepare a filter cake.
And 8: the filter cake obtained in step 7 was removed and treated with ultrasound.
The sonication is intended to open the lamella gap.
And step 9: and (4) treating the filter cake prepared in the step (8) by using a centrifugal machine, separating acid liquor, and keeping solid.
Step 10: and (4) freeze-drying the solid obtained in the step (9) to obtain powder.
As shown in fig. 1, the effect obtained by detecting graphene oxide under an Atomic Force Microscope (AFM) is shown, and the thickness of the graphene is 6.0 nm.
As shown in fig. 2, the effect obtained by scanning graphene oxide with an electron microscope (SEM) is shown.
The above description is only a preferred embodiment of the present invention, and all equivalent substitutions and deductions made by those skilled in the art according to the above embodiments should fall within the scope of the present invention.
Claims (3)
1. A method for preparing graphene oxide by using vermicular graphite is characterized by comprising the following steps:
step 1: crushing a plurality of 600 times of worm graphite by using a wall breaking machine into worm graphite powder;
step 2: 0.4-0.5g of sodium nitrate is put into 60-63ml of concentrated sulfuric acid, and the mixture is stirred in an ice water bath for 1 hour to be dispersed and turbid;
and step 3: 1g of the graphite powder prepared in the step 1 is put into the concentrated sulfuric acid-sodium nitrate mixed solution prepared in the step 2, 2-3g of potassium permanganate is slowly put into the mixed solution, the temperature is controlled to be 9-10 ℃ in an ice water bath, and the mixed solution is prepared after stirring for 3 hours;
and 4, step 4: placing the mixed solution prepared in the step 3 in an oil bath kettle at the temperature of 35 ℃ and stirring for 2 hours;
and 5: adding 180ml of deionized water with the temperature of 80 ℃ into the mixed solution prepared in the step 4, raising the temperature of the mixed solution to 95 ℃, and keeping the temperature for 0.5 hour;
step 6: adding 10ml of hydrogen peroxide into the mixed solution prepared in the step 5;
and 7: filtering the mixed solution prepared in the step 6, and washing with deionized water to prepare a filter cake;
and 8: taking the filter cake obtained in the step 7 down, and treating the filter cake with ultrasonic waves;
and step 9: treating the filter cake prepared in the step 8 by using a centrifugal machine, separating acid liquor, and reserving solid;
step 10: and (4) freeze-drying the solid obtained in the step (9) to obtain powder.
2. The method for preparing graphene oxide from vermicular graphite according to claim 1, which is characterized by comprising the following steps:
step 1: crushing a plurality of 600 times of worm graphite by using a wall breaking machine into worm graphite powder;
step 2: 0.4g of sodium nitrate is put into 60ml of concentrated sulfuric acid, and the mixture is stirred in an ice water bath for 1 hour to be dispersed and turbid;
and step 3: 1g of the graphite powder prepared in the step 1 is put into the concentrated sulfuric acid-sodium nitrate mixed solution prepared in the step 2, 2g of potassium permanganate is slowly put into the mixed solution, the temperature is controlled to be 9-10 ℃ in an ice water bath, and the mixed solution is prepared after stirring for 3 hours;
and 4, step 4: placing the mixed solution prepared in the step 3 in an oil bath kettle at the temperature of 35 ℃ and stirring for 2 hours;
and 5: adding 180ml of deionized water with the temperature of 80 ℃ into the mixed solution prepared in the step 4, raising the temperature of the mixed solution to 95 ℃, and keeping the temperature for 0.5 hour;
step 6: adding 10ml of hydrogen peroxide into the mixed solution prepared in the step 5;
and 7: filtering the mixed solution prepared in the step 6, and washing with deionized water to prepare a filter cake;
and 8: taking the filter cake obtained in the step 7 down, and treating the filter cake with ultrasonic waves;
and step 9: treating the filter cake prepared in the step 8 by using a centrifugal machine, separating acid liquor, and reserving solid;
step 10: and (4) freeze-drying the solid obtained in the step (9) to obtain powder.
3. The method for preparing graphene oxide from vermicular graphite according to claim 1, which is characterized by comprising the following steps:
step 1: crushing a plurality of 600 times of worm graphite by using a wall breaking machine into worm graphite powder;
step 2: 0.5g of sodium nitrate is put into 63ml of concentrated sulfuric acid, and the mixture is stirred in an ice water bath for 1 hour to be dispersed and turbid;
and step 3: 1g of the graphite powder prepared in the step 1 is put into the concentrated sulfuric acid-sodium nitrate mixed solution prepared in the step 2, and then 3g of potassium permanganate is slowly put into the mixed solution, the temperature is controlled to be 9-10 ℃ in an ice water bath, and the mixed solution is prepared after stirring for 3 hours;
and 4, step 4: placing the mixed solution prepared in the step 3 in an oil bath kettle at the temperature of 35 ℃ and stirring for 2 hours;
and 5: adding 180ml of deionized water with the temperature of 80 ℃ into the mixed solution prepared in the step 4, raising the temperature of the mixed solution to 95 ℃, and keeping the temperature for 0.5 hour;
step 6: adding 10ml of hydrogen peroxide into the mixed solution prepared in the step 5;
and 7: filtering the mixed solution prepared in the step 6, and washing with deionized water to prepare a filter cake;
and 8: taking the filter cake obtained in the step 7 down, and treating the filter cake with ultrasonic waves;
and step 9: treating the filter cake prepared in the step 8 by using a centrifugal machine, separating acid liquor, and reserving solid;
step 10: and (4) freeze-drying the solid obtained in the step (9) to obtain powder.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201911037483.1A CN110980717A (en) | 2019-10-29 | 2019-10-29 | Method for preparing graphene oxide by using vermicular graphite |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201911037483.1A CN110980717A (en) | 2019-10-29 | 2019-10-29 | Method for preparing graphene oxide by using vermicular graphite |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN110980717A true CN110980717A (en) | 2020-04-10 |
Family
ID=70082713
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201911037483.1A Withdrawn CN110980717A (en) | 2019-10-29 | 2019-10-29 | Method for preparing graphene oxide by using vermicular graphite |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN110980717A (en) |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103408000A (en) * | 2013-07-25 | 2013-11-27 | 黑龙江科技大学 | Preparation method for oxidized grapheme in large sheet |
| CN103787317A (en) * | 2014-01-02 | 2014-05-14 | 上海应用技术学院 | Preparation method of graphene oxide dispersion liquid |
| CN106629673A (en) * | 2016-09-13 | 2017-05-10 | 钢铁研究总院 | Preparation method for graphene oxide |
| US20180339906A1 (en) * | 2015-11-16 | 2018-11-29 | Fudan University | Preparation method for large-size graphene oxide or graphene |
| CN110104633A (en) * | 2019-04-27 | 2019-08-09 | 北京鼎臣石墨科技有限公司 | A kind of preparation method of graphene oxide and graphene |
-
2019
- 2019-10-29 CN CN201911037483.1A patent/CN110980717A/en not_active Withdrawn
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103408000A (en) * | 2013-07-25 | 2013-11-27 | 黑龙江科技大学 | Preparation method for oxidized grapheme in large sheet |
| CN103787317A (en) * | 2014-01-02 | 2014-05-14 | 上海应用技术学院 | Preparation method of graphene oxide dispersion liquid |
| US20180339906A1 (en) * | 2015-11-16 | 2018-11-29 | Fudan University | Preparation method for large-size graphene oxide or graphene |
| CN106629673A (en) * | 2016-09-13 | 2017-05-10 | 钢铁研究总院 | Preparation method for graphene oxide |
| CN110104633A (en) * | 2019-04-27 | 2019-08-09 | 北京鼎臣石墨科技有限公司 | A kind of preparation method of graphene oxide and graphene |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| WO2015109916A1 (en) | Method for preparing graphene | |
| CN103539108B (en) | A kind of method preparing graphene oxide | |
| US10472243B2 (en) | Industrial method for preparing large-sized graphene | |
| CN102153077A (en) | Method for preparing single-layer graphene with high carbon-oxygen ratio | |
| CN110723737B (en) | Wool ball type Ti3C2Preparation method and application of (MXene) nano material | |
| CN103288069A (en) | Method for preparing fluorinated graphene through microwave hydrothermal method | |
| CN104071777B (en) | A kind of preparation method of Graphene | |
| CN104386678B (en) | A kind of preparation method of Graphene | |
| CN112758950B (en) | Boron alkene nanosheets and preparation method thereof | |
| CN104556221A (en) | TiO2/lamellar graphite nano composite material as well as preparation method thereof | |
| CN105585003B (en) | A kind of large-scale continuous preparation method and its equipment of graphene oxide and graphene nanometer sheet | |
| CN105060288A (en) | Method for preparing graphene from biomass waste | |
| CN106629689B (en) | Graphene oxide or the efficient catalytic magnanimity preparation method of its compound are removed based on microwave reduction | |
| CN107555423B (en) | Stripping solution for preparing two-dimensional nano material and application thereof | |
| CN110255548B (en) | Method for preparing water-dispersible graphene slurry | |
| CN112142101A (en) | Preparation method of single-layer two-dimensional nano material MXene | |
| CN105944721A (en) | Hydrothermal preparation method of flaky nano copper oxide/graphene composite materials | |
| CN103072980A (en) | Method for quickly preparing graphene sheets | |
| CN106629676A (en) | Alkaline-electrolyte-based graphene preparation method | |
| CN111792669B (en) | TiO 22Nano-rod/multilayer graphene composite material and preparation method thereof | |
| CN105671611B (en) | A kind of method that graphene surface directly loads nano-oxide | |
| CN111320150A (en) | Method for preparing hexagonal boron nitride nanosheets by ion insertion ultrasonic stripping of alkali metal salt | |
| CN111389316B (en) | Sea urchin-like microsphere and preparation method thereof | |
| CN110980717A (en) | Method for preparing graphene oxide by using vermicular graphite | |
| CN110937584A (en) | Boron nitride nanosheet 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 | ||
| WW01 | Invention patent application withdrawn after publication | ||
| WW01 | Invention patent application withdrawn after publication |
Application publication date: 20200410 |