CN109467926A - Wear-resisting slurry is preparing the application in abrasion-resistant bearing materials - Google Patents
Wear-resisting slurry is preparing the application in abrasion-resistant bearing materials Download PDFInfo
- Publication number
- CN109467926A CN109467926A CN201811311163.6A CN201811311163A CN109467926A CN 109467926 A CN109467926 A CN 109467926A CN 201811311163 A CN201811311163 A CN 201811311163A CN 109467926 A CN109467926 A CN 109467926A
- Authority
- CN
- China
- Prior art keywords
- wear
- stirring
- minutes
- abrasion
- added
- 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- Withdrawn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
Classifications
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L79/00—Compositions of macromolecular compounds obtained by reactions forming in the main chain of the macromolecule a linkage containing nitrogen with or without oxygen or carbon only, not provided for in groups C08L61/00 - C08L77/00
- C08L79/04—Polycondensates having nitrogen-containing heterocyclic rings in the main chain; Polyhydrazides; Polyamide acids or similar polyimide precursors
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
- C08K3/00—Use of inorganic substances as compounding ingredients
- C08K3/32—Phosphorus-containing compounds
- C08K2003/321—Phosphates
- C08K2003/327—Aluminium phosphate
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L2205/00—Polymer mixtures characterised by other features
- C08L2205/03—Polymer mixtures characterised by other features containing three or more polymers in a blend
- C08L2205/035—Polymer mixtures characterised by other features containing three or more polymers in a blend containing four or more polymers in a blend
Abstract
The present invention provides wear-resisting slurries to prepare the application in abrasion-resistant bearing materials, and resin system is added in organic solvent, and micron filler, polycaprolactone diols are added after stirring；Wear-resisting slurry is obtained after being again stirring for；Wear-resisting slurry is coated on the steel plate with copper powder, heat treatment obtains abrasion-resistant bearing materials.The present invention is by process choice, and during the reaction, the probability to contact with each other between raw material is higher, avoids overreact from causing thermal response uneven in mixed process, faster, cross-linked network production rate is higher for reaction speed when hot；By adjusting stirring, thermal response temperature and time, extent of reaction when mixing is controlled, method is ingenious in design and reasonable；Include inorganic material, metallic compound etc. by addition additive, increases the wear-resistant strength of resin matrix composite material.
Description
Technical field
The invention belongs to technical field of composite materials, and in particular to wear-resisting slurry is preparing answering in abrasion-resistant bearing materials
With.
Background technique
Composite material has in fields such as metallurgy, non-ferrous metal, machinery, petrochemical industry, electric power to be extremely widely applied.Composite wood
Material has the characteristics such as density small, flexibility is high, waterproof, collects waste heat, random good, no cavity can avoid negative wind pressure
It tears and falls off.Self-lubricating bearing due to be suitable for lubricating it is unreliable or can not place and start to be valued by people.It is single
The self-lubricating bearing of one material generally has copper powders to control gold and two kinds of structures of plastics.Copper powder metallurgy structural strength is relatively low, difficult
To be suitble to the operating condition of top load, also easily cause to pull in running-in period.Existing bearing material requires addition curing
Molybdenum etc. is used as wear phase, is not otherwise available.
Summary of the invention
The present invention provides wear-resisting slurries to prepare the application in abrasion-resistant bearing materials, with epoxy combination cyanate, passes through
The selection compatibility of resin matrix and small-molecule substance obtains wear-resisting slurry in conjunction with reasonable preparation process, prepared therefrom wear-resisting
Bearing material has excellent wear-resisting property, while having good processing performance.
To achieve the above object of the invention, the present invention adopts the following technical scheme:
Wear-resisting slurry is preparing the application in abrasion-resistant bearing materials, the preparation method of the wear-resisting slurry, including following step
It is rapid:
(1) Nickelous nitrate hexahydrate, ruthenium trichloride, urea are added to the water, mica powder is added after stirring；Add after being again stirring for
Enter SODIUM PERCARBONATE, third time obtains filler mixture after stirring；Then by vacuum heat treatment behind mixture merging square position, powder is obtained
Material；Then powder is calcined to obtain block；Finally block is crushed to obtain a micron filler；
(2) allyl ylboronic acid is added in cyanate, diethylbenzene phosphate and tetraethoxy-silicane is added after heating stirring
Triglycidyl group cyamelide ester monomer, isotridecyl acrylate is added in alkane after being again stirring for, add after continuing stirring
Enter benzaldehyde, manganese acetate；It is placed in square position after finally stirring, breaks into pieces to obtain resin system after natural cooling；
(3) resin system is added in organic solvent, micron filler, polycaprolactone diols is added after stirring；It stirs again
Wear-resisting slurry is obtained after mixing.
In above-mentioned technical proposal, wear-resisting slurry is coated on the steel plate with copper powder, heat treatment obtains wear-resisting shaft corbel
Material.
In above-mentioned technical proposal, Nickelous nitrate hexahydrate, ruthenium trichloride, urea, water, mica powder, SODIUM PERCARBONATE mass ratio
It is 10: 8: 12: 100: 35: 2；Allyl ylboronic acid, cyanate, diethylbenzene phosphate, tetraethoxysilane, triglycidyl group
Cyamelide ester monomer, isotridecyl acrylate, benzaldehyde, manganese acetate mass ratio be 10: 100: 8: 10: 80: 15:
25:2；Resin system, micron filler, polycaprolactone diols mass ratio be 100: 30: 10.
In above-mentioned technical proposal, the solid content of wear-resisting slurry is 82~83%；It can be obtained by solvent usage and volatilization
To the wear-resisting slurry of suitable solid content, the present invention limits high solids content slurry, it is possible to reduce reaction defect, when post-processing
Reduce solvent volatilization bring such as stomata, it is uneven the problems such as, it is often more important that, by the design of resin system and gather oneself
The addition of lactone dihydric alcohol solves the problems, such as that existing slurry could can only effectively solidify using lower than 65% solid content, and subtracts
Few solvent contamination reduces cost, improves controllability.
In above-mentioned technical proposal, the partial size of micron filler is micron order, preferably 200~350 microns, overcomes the prior art
Think the prejudice that nanofiller is just applicable in, the filler of 200~350 micron grain size of limiting sense obtains good dispersibility, phase
Capacitive and play excellent wearability.
In above-mentioned technical proposal, in step (1), the time that SODIUM PERCARBONATE is added is 10~15 minutes；The time of stirring is
30 minutes；The time being again stirring for is 15 minutes；The time of third time stirring is 50 minutes；The temperature of vacuum heat treatment is 120
DEG C, vacuum degree is without limitation；The temperature of calcining is 550 DEG C, and the time is 1.5 hours；Block crushes to obtain powder when micron filler
Broken is the prior art.The addition of SODIUM PERCARBONATE can provide bubble mixed effect, can be improved compared to other sodium salts are directly added into
Each element mixes performance, can also provide sodium element, help the reaction of resin.The newly-designed filler of the present invention is not advise after crushing
Then shape, and non-existing regular (circle etc.) filler, preferable interface interaction can be generated with the Micron Copper Powder on steel plate, is increased
Abrasion resistant effect, and filler contains ruthenium element, and the wearability of filler and the performance of resin system can be improved, to obtain resistance to
Grind excellent composite layer.
In above-mentioned technical proposal, in step (2), the temperature of heating stirring is 95 DEG C, and the time is 30 minutes；It is again stirring for
Temperature is 115 DEG C, and the time is 90 minutes；The temperature for continuing stirring is 115 DEG C, and the time is 30 minutes；Finally churned temperature is
135 DEG C, the time is 20 minutes；It breaks into pieces as the prior art.It is added in macromolecule matrix using several small molecule compounds, Ke Yiti
The respond of system and the adhesive property after solidification when height heat treatment, and theoretically, allyl ylboronic acid and benzaldehyde can
It is advantageous to mixing, the reaction of epoxy and cyanate to generate alcohol；The addition of manganese dioxide can improve reaction in heat treatment
Property.
In above-mentioned technical proposal, in step (3), organic solvent is the mixed solvent of acetone and ethyl alcohol, preferably acetone and second
The mass ratio of alcohol is 2: 1；The time of stirring is 30 minutes；The time being again stirring for is 75 minutes.In the case where limiting resin system, this
Invention can use hypotoxicity, easy volatile solvent, not only meet environment-protecting industrial demand for development, but also improve production controllability, it is important to
In composite material coated in surface of steel plate, solvent residual amount is few, volatilization is easy, and various defects can be generated by solving existing heat treatment
The problem of.
In above-mentioned technical proposal, applied to spraying, specific spraying is the prior art；Process of thermal treatment is 75 DEG C/10 points
+ 250 DEG C of+150 DEG C of clock/20 minute/15 minute may be implemented composite material and be bonded in the solidification of surface of steel plate, prior art heat
Treatment temperature is too high, sacrifices macromolecule and has saved some inorganic wear resistant components such as molybdenum disulfide etc. from damage.The another Case road of the present invention,
Polymer composite is introduced in Copper Powder Surface and gap, has given full play to the adhesive property, wear-resisting of polymer composite
Performance；Wherein the steel plate with copper powder can be sintered to obtain using the prior art.
The present invention is by process choice, and during the reaction, the probability to contact with each other between raw material is higher, in mixed process
Overreact is avoided to cause thermal response uneven, faster, cross-linked network production rate is higher for reaction speed when hot；Stirred by adjusting,
Thermal response temperature and time, extent of reaction when control mixes, method are ingenious in design and reasonable；It include inorganic by addition additive
Material, metallic compound etc. increase the wear-resistant strength of resin matrix composite material.
Specific embodiment
The wear-resisting slurry of embodiment one is preparing the application in abrasion-resistant bearing materials, comprising the following steps:
(1) 100g Nickelous nitrate hexahydrate, 80g ruthenium trichloride, 120g urea are added in 1Kg water, are added after stirring 30 minutes
Enter 35g mica powder；20g SODIUM PERCARBONATE is added after being again stirring for 15 minutes, adds within 15 minutes, third time stirring obtains after 50 minutes
Filler mixture；Then 120 DEG C of vacuum heat treatment behind square position is poured the mixture into, vacuum environment is conventional vacuum baking oven, is obtained
Powder；Then 550 DEG C of powder calcinings are obtained into block in 1.5 hours；Finally block is crushed to obtain partial size to be 200~350 microns
Micron filler；
(2) 100g allyl ylboronic acid is added in 1000g cyanate, 95 DEG C 80g diethyl is added after heating stirring 30 minutes
Base benzenephosphonic acid ester and 100g tetraethoxysilane, 115 DEG C be again stirring for 90 points after 800g triglycidyl group trimerization isocyanide is added
Acid ester monomer, 150g isotridecyl acrylate, 115 DEG C are continued that 250g benzaldehyde, 20g acetic acid is added after stirring 30 minutes
Manganese；Last 135 DEG C of stirrings are poured into square position after twenty minutes, break into pieces to obtain resin system after natural cooling；
(3) 1000g resin system is added to the in the mixed solvent of 1000g acetone and 500g ethyl alcohol, is added after stirring 30 minutes
Enter 300g microns of fillers, 100g polycaprolactone diols；The wear-resisting slurry that solid content is 82% is obtained after being again stirring for 75 minutes,
By addition solvent or mixing speed control can be adjusted；
(4) wear-resisting slurry is sprayed on the existing steel plate with copper powder, heat treatment obtains abrasion-resistant bearing materials, is heat-treated
Technique be+250 DEG C/15 minutes+150 DEG C/20 minutes 75 DEG C/10 minutes.
Comparative example one
The micron filler of embodiment one is replaced with to the mixing of existing anti-friction bearing molybdenum disulfide, silica, graphite
Object, remaining is consistent with embodiment one.
Comparative example two
The SODIUM PERCARBONATE of embodiment one is removed, remaining is consistent with embodiment one.
Comparative example three
The ruthenium trichloride of embodiment one is removed, remaining is consistent with embodiment one.
Comparative example four
The manganese acetate of embodiment one is removed, remaining is consistent with embodiment one.
Comparative example five
The polycaprolactone diols of embodiment one is removed, remaining is consistent with embodiment one.
Comparative example six
The process of thermal treatment of embodiment one is revised as 120 DEG C/30 minutes+250 DEG C/15 minutes, remaining and embodiment
One is consistent.
1 bearing material performance characterization of table
Table 1 is bearing material correlated performance prepared by embodiment and comparative example, wherein using Brinell hardness analyzer pair
Sintered steel plate hardness measures, and measures at every plate centre and quadrangle totally five；, it is apparent that product of the invention
Have excellent comprehensive performance, especially wearability；Simultaneously with 3mol/L sodium hydroxide solution, 3mol/L sodium chloride solution and
The acetum of 3mol/L carries out corrosion-resistant test respectively, and the time is 50 hours, and embodiment product wearing face, which does not have, to be become
Change, maintain original state, there is good anticorrosion effect, obvious corrosion phenomenon, face occurs in one product surface of comparative example
Color slightly turns to be yellow, and two product surface of comparative example is unchanged, the faint corrosion of three product surface of comparative example, and four product surface of comparative example is slight
Corrosion, five product surface slight erosion of comparative example, six product surface slight erosion of comparative example.
Claims (9)
1. wear-resisting slurry is preparing the application in abrasion-resistant bearing materials, which is characterized in that the preparation method of the wear-resisting slurry, packet
Include following steps:
(1) Nickelous nitrate hexahydrate, ruthenium trichloride, urea are added to the water, mica powder is added after stirring；It was added after being again stirring for
Sodium carbonate, third time obtain filler mixture after stirring；Then by vacuum heat treatment behind mixture merging square position, powder is obtained；
Then powder is calcined to obtain block；Finally block is crushed to obtain a micron filler；
(2) allyl ylboronic acid is added in cyanate, diethylbenzene phosphate and tetraethoxysilane is added after heating stirring, then
Triglycidyl group cyamelide ester monomer, isotridecyl acrylate are added after secondary stirring, benzene is added after continuing stirring
Formaldehyde, manganese acetate；It is placed in square position after finally stirring, breaks into pieces to obtain resin system after natural cooling；
(3) resin system is added in organic solvent, micron filler, polycaprolactone diols is added after stirring；After being again stirring for
Obtain wear-resisting slurry.
2. wear-resisting slurry is preparing the application in abrasion-resistant bearing materials according to claim 1, which is characterized in that six hydration nitre
Sour nickel, ruthenium trichloride, urea, water, mica powder, SODIUM PERCARBONATE mass ratio be 10: 8: 12: 100: 35: 2；Allyl ylboronic acid, cyanogen
Acid esters, diethylbenzene phosphate, tetraethoxysilane, triglycidyl group cyamelide ester monomer, isotridecyl propylene
Acid esters, benzaldehyde, manganese acetate mass ratio be 10: 100: 8: 10: 80: 15: 25: 2；Resin system, micron filler, polycaprolactone
The mass ratio of dihydric alcohol is 100: 30: 10.
3. wear-resisting slurry is preparing the application in abrasion-resistant bearing materials according to claim 1, which is characterized in that wear-resisting slurry
Solid content be 82~83%；The partial size of micron filler is 200~350 microns.
4. wear-resisting slurry is preparing the application in abrasion-resistant bearing materials according to claim 1, which is characterized in that step (1)
In, the time that SODIUM PERCARBONATE is added is 10~15 minutes；The time of stirring is 30 minutes；The time being again stirring for is 15 minutes；
The time of third time stirring is 50 minutes；The temperature of vacuum heat treatment is 120 DEG C；The temperature of calcining is 550 DEG C, the time 1.5
Hour.
5. wear-resisting slurry is preparing the application in abrasion-resistant bearing materials according to claim 1, which is characterized in that step (2)
In, the temperature of heating stirring is 95 DEG C, and the time is 30 minutes；The temperature being again stirring for is 115 DEG C, and the time is 90 minutes；Continue
The temperature of stirring is 115 DEG C, and the time is 30 minutes；Finally churned temperature is 135 DEG C, and the time is 20 minutes.
6. wear-resisting slurry is preparing the application in abrasion-resistant bearing materials according to claim 1, which is characterized in that step (3)
In, organic solvent is the mixed solvent of acetone and ethyl alcohol；The time of stirring is 30 minutes；The time being again stirring for is 75 minutes.
7. wear-resisting slurry is preparing the application in abrasion-resistant bearing materials according to claim 6, which is characterized in that acetone and second
The mass ratio of alcohol is 2: 1.
8. wear-resisting slurry is preparing the application in abrasion-resistant bearing materials according to claim 1, which is characterized in that by resistance to defibrination
Material is coated on the steel plate with copper powder, and heat treatment obtains abrasion-resistant bearing materials.
9. wear-resisting slurry is preparing the application in abrasion-resistant bearing materials according to claim 8, which is characterized in that heat treatment
Technique is+250 DEG C/15 minutes+150 DEG C/20 minutes 75 DEG C/10 minutes.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201811311163.6A CN109467926A (en) | 2018-10-31 | 2018-10-31 | Wear-resisting slurry is preparing the application in abrasion-resistant bearing materials |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201811311163.6A CN109467926A (en) | 2018-10-31 | 2018-10-31 | Wear-resisting slurry is preparing the application in abrasion-resistant bearing materials |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN109467926A true CN109467926A (en) | 2019-03-15 |
Family
ID=65671702
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201811311163.6A Withdrawn CN109467926A (en) | 2018-10-31 | 2018-10-31 | Wear-resisting slurry is preparing the application in abrasion-resistant bearing materials |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN109467926A (en) |
Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3170003A (en) * | 1958-10-01 | 1965-02-16 | Bayer Ag | Process of producing polyurethane plastics and resulting products |
| CN106941151A (en) * | 2016-01-05 | 2017-07-11 | 中国石油大学(北京) | A kind of graphene composite graphite negative electrode material and its preparation method and application |
| CN107140612A (en) * | 2017-06-26 | 2017-09-08 | 北京石油化工学院 | A kind of method for preparing phosphorus alkene nitrogen-doped carbon composite |
| CN107293705A (en) * | 2017-05-10 | 2017-10-24 | 华南农业大学 | Lithium ion battery bamboo charcoal/metal oxide composite cathode material and its preparation method and application |
| CN107383764A (en) * | 2017-07-28 | 2017-11-24 | 嘉兴立新材料有限公司 | A kind of compound low Heat Conduction Material and preparation method thereof |
| CN108130076A (en) * | 2016-12-01 | 2018-06-08 | 中国科学院大连化学物理研究所 | A kind of dry combustion method preparation method of transient metal doped carbon fluorescence quantum |
| CN108295861A (en) * | 2017-01-11 | 2018-07-20 | 龙岩紫荆创新研究院 | A kind of denitrating catalyst and preparation method thereof of two-stage active component |
| CN108440907A (en) * | 2018-01-27 | 2018-08-24 | 嘉兴立新材料有限公司 | A kind of preparation method of composite material with high dielectric property |
-
2018
- 2018-10-31 CN CN201811311163.6A patent/CN109467926A/en not_active Withdrawn
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3170003A (en) * | 1958-10-01 | 1965-02-16 | Bayer Ag | Process of producing polyurethane plastics and resulting products |
| CN106941151A (en) * | 2016-01-05 | 2017-07-11 | 中国石油大学(北京) | A kind of graphene composite graphite negative electrode material and its preparation method and application |
| CN108130076A (en) * | 2016-12-01 | 2018-06-08 | 中国科学院大连化学物理研究所 | A kind of dry combustion method preparation method of transient metal doped carbon fluorescence quantum |
| CN108295861A (en) * | 2017-01-11 | 2018-07-20 | 龙岩紫荆创新研究院 | A kind of denitrating catalyst and preparation method thereof of two-stage active component |
| CN107293705A (en) * | 2017-05-10 | 2017-10-24 | 华南农业大学 | Lithium ion battery bamboo charcoal/metal oxide composite cathode material and its preparation method and application |
| CN107140612A (en) * | 2017-06-26 | 2017-09-08 | 北京石油化工学院 | A kind of method for preparing phosphorus alkene nitrogen-doped carbon composite |
| CN107383764A (en) * | 2017-07-28 | 2017-11-24 | 嘉兴立新材料有限公司 | A kind of compound low Heat Conduction Material and preparation method thereof |
| CN108440907A (en) * | 2018-01-27 | 2018-08-24 | 嘉兴立新材料有限公司 | A kind of preparation method of composite material with high dielectric property |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN104480342A (en) | Anti-corrosion copper-based brake material with high friction coefficient and preparation method of anti-corrosion copper-based brake material | |
| CN107603420A (en) | Graphene corrosion-resistant epoxy paint and preparation method thereof | |
| CN101891415B (en) | Corrosion resistance coating for steel and preparation method thereof | |
| CN106810995B (en) | Nanometer alumina modified boron phenolic epoxy-organic silicon wear-and corrosion-resistant material and preparation | |
| CN105948755A (en) | Production method of silicon carbide micro powder applied to pressureless sintering | |
| CN109401592A (en) | A kind of preparation method of abrasion-resistant bearing materials | |
| CN102634320B (en) | Material of high-wear-resistance ceramic automobile brake block and preparation method thereof | |
| CN101021268A (en) | Light hard alloy seal ring and producing method thereof | |
| CN105086355A (en) | Slag powder reinforced resin matrix composite material for automobile braking | |
| CN103357867B (en) | A kind of Scale-like multi-component zinc aluminum silicon alloy powder and preparation method thereof | |
| CN110183896A (en) | Technique red mud modified composite modifier and its be surface-treated in coating filling with red mud | |
| CN109467926A (en) | Wear-resisting slurry is preparing the application in abrasion-resistant bearing materials | |
| CN110272650A (en) | Improve the composite modifier of compatibility and its in the application for preparing powdery paints | |
| CN103627918A (en) | High-density boron carbide composite material and preparation method thereof | |
| CN109504148A (en) | A kind of abrasion-resistant bearing materials | |
| CN109456679A (en) | A kind of anti-friction bearing slurry | |
| CN109385202A (en) | A kind of preparation method of anti-friction bearing slurry | |
| CN107033732B (en) | A kind of graphene coating and preparation method thereof | |
| CN109504149A (en) | A kind of preparation method of flame-proof abrasion-resistant bearing slurry | |
| CN109467927A (en) | A kind of flame-proof abrasion-resistant bearing slurry | |
| CN109401606A (en) | Flame-retardant slurry is preparing the application in flame-proof abrasion-resistant bearing material | |
| CN109385203A (en) | A kind of flame-proof abrasion-resistant bearing material | |
| CN109536033A (en) | A kind of preparation method of flame-proof abrasion-resistant bearing material | |
| CN108425059B (en) | A kind of Fe-A12O3Cermet sealing ring and preparation method thereof | |
| CN105060866A (en) | Ceramic cutting tool material with high mechanical strength and preparation method therefor |
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 |
Application publication date: 20190315 |
|
| WW01 | Invention patent application withdrawn after publication |