CN111019160A - Super-lyophobic polydimethylsiloxane microsphere and preparation method thereof - Google Patents
Super-lyophobic polydimethylsiloxane microsphere and preparation method thereof Download PDFInfo
- Publication number
- CN111019160A CN111019160A CN201911215023.3A CN201911215023A CN111019160A CN 111019160 A CN111019160 A CN 111019160A CN 201911215023 A CN201911215023 A CN 201911215023A CN 111019160 A CN111019160 A CN 111019160A
- Authority
- CN
- China
- Prior art keywords
- polydimethylsiloxane
- injection device
- microspheres
- water
- preparation
- 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
Images
Classifications
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
- C08J3/00—Processes of treating or compounding macromolecular substances
- C08J3/12—Powdering or granulating
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
- C08J2383/00—Characterised by the use of macromolecular compounds obtained by reactions forming in the main chain of the macromolecule a linkage containing silicon with or without sulfur, nitrogen, oxygen, or carbon only; Derivatives of such polymers
- C08J2383/04—Polysiloxanes
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
- C08J2383/00—Characterised by the use of macromolecular compounds obtained by reactions forming in the main chain of the macromolecule a linkage containing silicon with or without sulfur, nitrogen, oxygen, or carbon only; Derivatives of such polymers
- C08J2383/04—Polysiloxanes
- C08J2383/07—Polysiloxanes containing silicon bound to unsaturated aliphatic groups
Landscapes
- Chemical & Material Sciences (AREA)
- Health & Medical Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Medicinal Chemistry (AREA)
- Polymers & Plastics (AREA)
- Organic Chemistry (AREA)
- Processes Of Treating Macromolecular Substances (AREA)
- Manufacturing Of Micro-Capsules (AREA)
Abstract
The invention belongs to the technical field of high polymer materials, and particularly relates to an ultralyophobic polydimethylsiloxane microsphere and a preparation method thereof. The preparation method comprises the following steps: respectively preparing an oil phase and a water phase; bidirectional injection, mixing and emulsification; curing and drying to obtain the microsphere. The invention also provides the polydimethylsiloxane microsphere prepared by the method. The preparation method of the invention overcomes the defects of low surface tension and high fluid viscosity, and the particle size of the prepared microsphere breaks through the limit of 1 μm, and can reach 0.2 μm at least; meanwhile, the materials used by the microspheres prepared by the preparation method are all environment-friendly materials and are environment-friendly; the preparation method is also suitable for various end-capped polydimethylsiloxanes and polydimethylsiloxy derivatives besides vinyl and hydroxyl.
Description
Technical Field
The invention belongs to the technical field of high polymer materials, and particularly relates to an ultralyophobic polydimethylsiloxane microsphere and a preparation method thereof.
Background
Ultralyophobic refers to the action of strongly repelling spreading on liquid media, including aqueous to oily, small to large molecules, fluid to non-fluid, mono-to multi-component, non-biological to biological. The super-lyophobic surface can be widely applied to self-cleaning clothes, anti-adhesion medical catheters, oil-water separation, rail transit corrosion prevention, ship pollution prevention and the like. The polydimethylsiloxane substances comprise polydimethylsiloxane and polydimethylsiloxane derivatives with different end capping, have low surface energy, good chemical stability and strong mechanical flexibility, and have wide application prospect on the surface of super lyophobic liquid. Polydimethylsiloxane-type microspheres can self-provide microstructures and lower surface energy, and are extremely ideal units for forming ultralyophobic surfaces.
The chinese patent application No. 201610662946.3 discloses that the emulsion microspheres of polydimethylsiloxane prepolymer/curing agent mixture are formed by stirring and emulsification, and then heated to cure/dry to obtain the polydimethylsiloxane microspheres with labyrinth or dimple-like corrugated structure on the surface. The Chinese patent application No. 201711172189.2 discloses that the polydimethylsiloxane hollow nano-microsphere is obtained by polymerizing oil-soluble polydimethylsiloxane prepolymer in water-in-oil microemulsion and removing oil phase solvent, surfactant and water. The technical methods disclosed in the chinese patent application nos. 201610662946.3 and 201711172189.2 use non-environmental organic solvents or oily auxiliaries, and the low surface tension and high fluid viscosity of polydimethylsiloxane can only control the particle size of the microspheres to be more than 1 μm at the lowest, and is only suitable for polydimethylsiloxane end-capped with vinyl or hydroxyl groups.
Disclosure of Invention
In view of the above, it is necessary to provide a polydimethylsiloxane microsphere and a preparation method thereof.
The invention is realized by the following technical scheme:
a preparation method of super lyophobic polydimethylsiloxane microspheres comprises the following operations:
respectively preparing an oil phase and a water phase; mixing and emulsifying; curing and drying to prepare the microspheres.
Further, the operation of "separately preparing the oil phase and the water phase" includes:
mixing polydimethylsiloxane or derivatives thereof and a curing agent according to the mass ratio of 100: 3-15 (preferably 100:10) to form an oil phase; mixing a water-soluble surfactant and water according to a mass ratio of 1: 40-150 stirring and dissolving to form a water phase.
Preferably, the dimethyl siloxane or the derivative thereof and the curing agent form an oil phase without stirring; the water-soluble surfactant and water are stirred and dissolved at 300-800 rpm to form a water phase.
Further, the end capping of the polydimethylsiloxane is one of trimethylsiloxane, vinyl, methoxy, aminopropyl and hydroxyl.
Further, the derivative of the polydimethylsiloxane is one of polydimethylsiloxane-isophorone diisocyanate, polydimethylsiloxane-4, 4' -diphenylmethane diisocyanate, polydimethylsiloxane-polyarylether and polydimethylsiloxane-polyvinyl acetate.
Further, the curing agent is one of dibutyl tin dilaurate, hydrogen-containing silicone oil, ethyl orthosilicate, polyalkoxysilane and polyaminosilane.
Further, the water-soluble surfactant is one of cationic fluorine-containing polyacrylate, anionic fluorine-containing polyacrylate, nonionic fluorine-containing polyacrylate, polyvinylpyrrolidone, polyvinyl alcohol and polyethylene glycol.
Further, the mixing emulsification is mixing emulsification in a bidirectional injection mode, and emulsification is realized through fluid shear stress shock.
Further, the operation of "bi-directional injection" includes:
filling the obtained oil phase into a first injection device, filling the obtained water phase into a second injection device, wherein the first injection device and the second injection device are communicated with each other;
injecting the aqueous phase in the second injection device into the oil phase of the first injection device, and mixing the oil phase and the aqueous phase; and then injecting the mixed liquid in the second injection device into the first injection device, and repeatedly circulating to form emulsion.
Further, the injection device is an injector or a device capable of achieving the same or equivalent function as the injector plays in the bidirectional injection operation; the syringe model is preferably one of 15G, 17G, 19G, 21G and 23G.
Further, the repeated cycle is 10-70 times.
Further, the operation of "curing and drying" includes: stirring the obtained emulsion at 200-700 rpm, and injecting the emulsion into high-temperature water for a period of time; and (3) transferring the obtained solution into a centrifugal tube to be washed and dried at 800-5000 rpm, and obtaining the polydimethylsiloxane microsphere.
Further, the temperature of the high-temperature water is 70-100 ℃, and the duration time is 5-60 min.
Further, the drying conditions are as follows: the temperature is 50-100 ℃, and the duration is 30-100 min.
Furthermore, the particle size of the polydimethylsiloxane microsphere prepared by the method is 0.2-100 μm, preferably 0.2-20 μm.
The invention has the beneficial effects that:
the invention respectively prepares a polydimethylsiloxanyl oil phase and an environment-friendly water phase; the emulsion is formed by mixing the oil phase and the water phase in a sudden change way of fluid shear stress generated by bidirectional injection, and the polydimethylsiloxane microspheres are formed after solidification and drying, so that the low surface tension and high fluid viscosity are overcome, and the particle size of the prepared microspheres breaks through the limit of 1 mu m and can reach 0.2 mu m at minimum.
According to the method for preparing the polydimethylsiloxane microspheres, the used oil phase raw materials and water phase medium raw materials are environment-friendly materials, and besides vinyl and hydroxyl, the method is also suitable for other types of end-capped polydimethylsiloxane and various polydimethylsiloxane derivatives.
Drawings
FIG. 1 is a scanning electron microscope image of the ultralyophobic polydimethylsiloxane-based microspheres of the present invention.
Detailed Description
In order to better explain the problems to be solved, the technical solutions adopted and the beneficial effects achieved by the technical solutions of the present invention, further description will be given with reference to specific embodiments. It should be noted that the technical solutions of the present invention include, but are not limited to, the following embodiments.
The specific techniques or conditions not specified in the examples of the present invention are performed according to the techniques or conditions described in the literature in the art or according to the product specification. The reagents or instruments used are not indicated by manufacturers, and are all conventional products which can be obtained by commercial purchase and the like.
Example one
Mixing vinyl-terminated polydimethylsiloxane and a curing agent dibutyl tin dilaurate according to a mass ratio of 100: 9 forming an oil phase without stirring; stirring and dissolving environment-friendly anionic fluorine-containing polyacrylate and water according to the mass ratio of 1: 100400 rpm to form a water phase; filling the obtained oil phase into a syringe A (a first injection device) of an injector, filling the obtained water phase into a syringe B (a second injection device), and connecting the syringe A and the syringe B through a 19G double-guide needle; pushing the piston of the needle cylinder B to inject the water phase into the needle cylinder A, then pushing the piston of the needle cylinder A to inject the mixed solution into the needle cylinder B, and repeating the cycle for 30 times to form emulsion; the obtained emulsion is stirred at 300rpm and then injected into high-temperature water with the temperature of 100 ℃ for 5 min; the obtained solution is transferred into a centrifuge tube with 900rpm for washing and dried at 80 ℃ for 60min, and then the polydimethylsiloxane microsphere with the particle size of about 0.3 mu m is obtained (as shown in figure 1).
Example two
The preparation method comprises the following steps of (1) mixing polydimethylsiloxane blocked as hydroxyl and curing agent poly-alkoxy silane according to the mass ratio of 100: 11 forming an oil phase without stirring; stirring and dissolving environment-friendly polyvinyl alcohol and water according to the mass ratio of 1: 80500 rpm to form a water phase; filling the obtained oil phase into a syringe A (a first injection device) of an injector, filling the obtained water phase into a syringe B (a second injection device), and connecting the syringe A and the syringe B through a 21G double-guide needle; pushing the piston of the needle cylinder B to inject the water phase into the needle cylinder A, then pushing the piston of the needle cylinder A to inject the mixed solution into the needle cylinder B, and repeating the cycle for 40 times to form emulsion; the obtained emulsion is stirred at 300rpm and then injected into high-temperature water with the temperature of 80 ℃ for 60 min; and (3) transferring the obtained solution into a centrifugal tube of 2000rpm for washing, and drying at 100 ℃ for 30min to obtain the polydimethylsiloxane microspheres with the particle size of about 20 mu m.
EXAMPLE III
And (2) mixing polydimethylsiloxane blocked by methoxyl with curing agent tetraethoxysilane according to the mass ratio of 100: 14 forming an oil phase without stirring; stirring and dissolving the environment-friendly nonionic fluorine-containing polyacrylate and water according to the mass ratio of 1: 150700 rpm to form a water phase; filling the obtained oil phase into a syringe A (a first injection device) of an injector, filling the obtained water phase into a syringe B (a second injection device), and connecting the syringe A and the syringe B through a 15G double-guide needle; pushing the piston of the needle cylinder B to inject the water phase into the needle cylinder A, then pushing the piston of the needle cylinder A to inject the mixed solution into the needle cylinder B, and repeating the cycle for 70 times to form emulsion; the obtained emulsion is stirred at 600rpm and then injected into high-temperature water with the temperature of 70 ℃ for 35 min; and (3) transferring the obtained solution into a centrifuge tube with 3000rpm for washing, and drying at 50 ℃ for 100min to obtain the polydimethylsiloxane microspheres with the particle size of about 8 mu m.
The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the present invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.
Claims (10)
1. A preparation method of super lyophobic polydimethylsiloxane microspheres is characterized by comprising the following steps: respectively preparing an oil phase and a water phase; mixing and emulsifying are realized through fluid shear stress shock; curing and drying to obtain the microsphere.
2. The method of preparing ultralyophobic polydimethylsiloxane-type microspheres according to claim 1, wherein the operation of separately preparing the oil phase and the water phase comprises:
mixing polydimethylsiloxane or derivatives thereof and a curing agent according to the mass ratio of 100: 3-15 forming an oil phase; stirring and dissolving a water-soluble surfactant and water according to a mass ratio of 1: 40-150 to form a water phase.
3. The method of preparing an ultralyophobic polydimethylsiloxane type microsphere according to claim 2, wherein the endcapping of the polydimethylsiloxane is one of trimethylsiloxane, vinyl, methoxy, aminopropyl, hydroxyl;
the derivative of the polydimethylsiloxane is one of polydimethylsiloxane-isophorone diisocyanate, polydimethylsiloxane-4, 4' -diphenylmethane diisocyanate, polydimethylsiloxane-polyarylether and polydimethylsiloxane-polyvinyl acetate;
the curing agent is one of dibutyl tin dilaurate, hydrogen-containing silicone oil, tetraethoxysilane, polyalkoxysilane and polyaminosilane;
the water-soluble surfactant is one of cationic fluorine-containing polyacrylate, anionic fluorine-containing polyacrylate, nonionic fluorine-containing polyacrylate, polyvinylpyrrolidone, polyvinyl alcohol and polyethylene glycol.
4. The method of preparing ultralyophobic polydimethylsiloxane-type microspheres according to claim 1, wherein the "two-way injection" comprises:
filling the obtained oil phase into a first injection device, filling the obtained water phase into a second injection device, wherein the first injection device and the second injection device are communicated with each other;
injecting the aqueous phase in the second injection device into the oil phase of the first injection device, and mixing the oil phase and the aqueous phase; and then injecting the mixed liquid in the second injection device into the first injection device, and repeatedly circulating to form emulsion.
5. The method of claim 4, wherein the injection device is a syringe or a device capable of performing the same or equivalent function as a syringe in a two-way injection operation.
6. The method of claim 4, wherein the number of cycles is 10 to 70.
7. The method of preparing ultralyophobic polydimethylsiloxane-type microspheres according to claim 1, wherein the "curing and drying" comprises: injecting the obtained emulsion into high-temperature water of 70-100 ℃ for a period of time under the condition of stirring at 200-700 rpm; and (3) transferring the obtained solution into a centrifugal tube to be washed and dried at 800-5000 rpm, and obtaining the ultra-lyophobic polydimethylsiloxane microspheres.
8. The method of claim 7, wherein the holding time is 5-60 min.
9. The method of claim 7, wherein the drying conditions are as follows: the temperature is 50-100 ℃, and the duration is 30-100 min.
10. Polydimethylsiloxane microspheres prepared according to the preparation method of the ultralyophobic polydimethylsiloxane microspheres of any one of claims 1 to 9, wherein the particle size of the microspheres is 0.2 to 100 μm.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201911215023.3A CN111019160A (en) | 2019-12-02 | 2019-12-02 | Super-lyophobic polydimethylsiloxane microsphere and preparation method thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201911215023.3A CN111019160A (en) | 2019-12-02 | 2019-12-02 | Super-lyophobic polydimethylsiloxane microsphere and preparation method thereof |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN111019160A true CN111019160A (en) | 2020-04-17 |
Family
ID=70203852
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201911215023.3A Pending CN111019160A (en) | 2019-12-02 | 2019-12-02 | Super-lyophobic polydimethylsiloxane microsphere and preparation method thereof |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN111019160A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111500067A (en) * | 2020-05-29 | 2020-08-07 | 长兴特殊材料（珠海）有限公司 | Porous organosilicon elastic microsphere and preparation method thereof |
Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106188582A (en) * | 2016-08-12 | 2016-12-07 | 四川大学 | Surface has the preparation method of the polydimethylsiloxane microsphere of pleated structure |
| CN106928476A (en) * | 2017-02-28 | 2017-07-07 | 江苏晨光涂料有限公司 | A kind of preparation method of the silicon rubber microballoon for light diffusing agent |
| CN107688015A (en) * | 2017-07-13 | 2018-02-13 | 北京工业大学 | A kind of preparation method for being used to strengthen the transparent dielectric microballoon fexible film of Raman diffused light spectral intensity |
| CN107903363A (en) * | 2017-11-21 | 2018-04-13 | 天津工业大学 | A kind of dimethyl silicone polymer hollow nanospheres and its preparation method and application |
| CN108359106A (en) * | 2018-03-26 | 2018-08-03 | 浙江新安化工集团股份有限公司 | A kind of preparation method of silicones microballoon lotion |
| CN109134909A (en) * | 2018-08-06 | 2019-01-04 | 浙江工业大学 | A kind of preparation method on the surface PDMS of pH response |
| CN110016149A (en) * | 2019-05-05 | 2019-07-16 | 中国科学院兰州化学物理研究所 | A kind of preparation method of high intensity organosilicon composite polyvinyl alcohol hydrogel |
| CN110387126A (en) * | 2019-06-12 | 2019-10-29 | 袁庆华 | A kind of preparation method of intumescent composite flame-retardant agent |
-
2019
- 2019-12-02 CN CN201911215023.3A patent/CN111019160A/en active Pending
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106188582A (en) * | 2016-08-12 | 2016-12-07 | 四川大学 | Surface has the preparation method of the polydimethylsiloxane microsphere of pleated structure |
| CN106928476A (en) * | 2017-02-28 | 2017-07-07 | 江苏晨光涂料有限公司 | A kind of preparation method of the silicon rubber microballoon for light diffusing agent |
| CN107688015A (en) * | 2017-07-13 | 2018-02-13 | 北京工业大学 | A kind of preparation method for being used to strengthen the transparent dielectric microballoon fexible film of Raman diffused light spectral intensity |
| CN107903363A (en) * | 2017-11-21 | 2018-04-13 | 天津工业大学 | A kind of dimethyl silicone polymer hollow nanospheres and its preparation method and application |
| CN108359106A (en) * | 2018-03-26 | 2018-08-03 | 浙江新安化工集团股份有限公司 | A kind of preparation method of silicones microballoon lotion |
| CN109134909A (en) * | 2018-08-06 | 2019-01-04 | 浙江工业大学 | A kind of preparation method on the surface PDMS of pH response |
| CN110016149A (en) * | 2019-05-05 | 2019-07-16 | 中国科学院兰州化学物理研究所 | A kind of preparation method of high intensity organosilicon composite polyvinyl alcohol hydrogel |
| CN110387126A (en) * | 2019-06-12 | 2019-10-29 | 袁庆华 | A kind of preparation method of intumescent composite flame-retardant agent |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111500067A (en) * | 2020-05-29 | 2020-08-07 | 长兴特殊材料（珠海）有限公司 | Porous organosilicon elastic microsphere and preparation method thereof |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN104624132B (en) | Epoxy resin self-repairing microcapsule and preparation method thereof | |
| JP3213035B2 (en) | Emulsion gelled silicone antifoaming composition and foaming system defoaming method using the same | |
| US20060063882A1 (en) | Process for preparing microrods using liquid-liquid dispersion | |
| CN111019160A (en) | Super-lyophobic polydimethylsiloxane microsphere and preparation method thereof | |
| KR20110058827A (en) | Article formed from electrospinning a dispersion | |
| CN111116975B (en) | Pickering emulsion gel based on mutual attraction of liquid drops and preparation method thereof | |
| CN106245138B (en) | A kind of preparation method of high recovery stress shape memory complex fiber material | |
| CN103421253A (en) | Preparation method of polystyrene hollow microballs and applications thereof | |
| CA1317074C (en) | Agent for the treatment of fibers | |
| JP2004131913A (en) | Fabric-coating synthetic having latent heat effect and method for forming the same | |
| CN101270551B (en) | Polylactic acid fibre disperse dyeing accelerant | |
| Wang et al. | Stable encapsulated air nanobubbles in water | |
| CN109569344B (en) | Method for preparing suspended micro-droplets by using micro-fluidic device | |
| KR20170038056A (en) | Process for making an aminosiloxane polymer nanoemulsion | |
| CN100473673C (en) | Acrylamide crosslinking copolymer emulsion and preparation method thereof | |
| CN103757728A (en) | Method for preparing fibers in linear structure through pickering emulsion electrospinning | |
| CN105131313B (en) | A kind of preparation method of hydroxypropyl methyl cellulose nanosphere | |
| CN103585936B (en) | A kind of preparation method of plastic hollow bead and its product prepared and application | |
| EP1251923B1 (en) | Formulation and production process of a compound for reducing foam | |
| CN109627499B (en) | Preparation method of biomass composite gel with shear thickening effect | |
| JPH10140480A (en) | Textile treating agent | |
| CN107151301A (en) | A kind of preparation method of polyureas porous carrier ball | |
| CN111454488A (en) | Bacterial cellulose-based composite protective material and preparation method thereof | |
| CN107266635B (en) | A kind of nano-cellulose compound temperature-sensitive type hydrogel and preparation method thereof | |
| CN111648044A (en) | Super-absorbent nanofiber membrane 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 | ||
| TA01 | Transfer of patent application right | ||
| TA01 | Transfer of patent application right |
Effective date of registration: 20220228 Address after: 412000 No. 01, open office, first floor, enterprise club, No. 9, Zhongda Road, Tianyuan District, Zhuzhou City, Hunan Province Applicant after: Zhuzhou Lvzhi New Material Technology Co.,Ltd. Address before: 511458 building a, 1121 Haibin Road, Nansha District, Guangzhou City, Guangdong Province Applicant before: GUANGZHOU INSTITUTE OF ADVANCED TECHNOLOGY, CHINESE ACADEMY OF SCIENCES |
|
| RJ01 | Rejection of invention patent application after publication | ||
| RJ01 | Rejection of invention patent application after publication |
Application publication date: 20200417 |