CN104209879A - Method for manufacturing soluble fixed soft abrasive-polishing film - Google Patents
Method for manufacturing soluble fixed soft abrasive-polishing film Download PDFInfo
- Publication number
- CN104209879A CN104209879A CN201410461448.3A CN201410461448A CN104209879A CN 104209879 A CN104209879 A CN 104209879A CN 201410461448 A CN201410461448 A CN 201410461448A CN 104209879 A CN104209879 A CN 104209879A
- Authority
- CN
- China
- Prior art keywords
- polishing
- abrasive
- film
- bonding agent
- polishing film
- 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.)
- Granted
Links
Abstract
The invention relates to a soluble fixed soft abrasive-polishing film, which comprises an abrasive layer and a substrate layer and has the thickness of 0.3 to 5mm. A soluble high-molecular material is used as a bonding agent of the abrasive layer, and a certain proportion of multilayer particle-diameter soft microfine abrasives are distributed and coated on the elastic substrate according to a certain rule. Small-particle-diameter abrasive particles not only can directly participate in a polishing process, but also can be used as a filling material and achieves the effect of supporting large particles, so that the content of a resin bonding agent in the polishing film is decreased, and the problems of film surface cracking and breakage are effectively solved. A specific nonpoisonous and harmless aqueous solvent is adopted in the machining process to solve the bonding agent on the surface layer of the polishing film, so that the holding force of he bonding agent for the abrasive particles is decreased to enable the bonding agent to fall off; on one hand, the passivated abrasive particles on the surface layer can be removed, so that the polishing film has more lasting polishing performance; on the other hand, the abrasive particles which are fixed on the surface of the polishing film and the abrasive particles which fall off and are dispersed into a polishing solution jointly act on a workpiece, so that the ultra-smooth high-efficiency surface polishing of the workpiece can be realized.
Description
Technical field
The present invention relates to grinding/polishing field, is a kind of solubility set mild abrasives polishing film preparation method specifically.
Background technology
Along with improving constantly of properties of product, modern optoelectronic information field requires more and more high to the machining accuracy of material and surface quality.Polishing technology always is a kind of topmost method of ultraprecise processing, is to reduce surface roughness, removal damage layer, obtains the whole manufacturing process smooth, not damaged is surperficial.Traditional free abrasive polishing that at present advanced ceramics manufacture field adopts exists that working (machining) efficiency is low, abrasive particle waste is serious, polishing fluid processing cost is high and the problem such as environmental pollution is serious, how to overcome the above problems, realize the important problem that advanced ceramics device high-quality, efficient, green polishing have become ultraprecise manufacture field.
Fixed abrasive material polishing technology is that development in recent years a kind of is expected to realize that advanced ceramics device is efficient, the new method of high-quality processing.But general fixed abrasive material polishing mainly adopts between the uniform plane polishing pad of projection, fixation abrasive grain projection and has groove, be difficult to minor diameter part or the processing of on-plane surface part.Existing film polishing grinding tool exists resinoid bond to be easily attached to the problems such as polished surface, cannot meet the needs of the high-quality batch production of advanced ceramics material components and parts.Therefore, research and develop a kind of efficient, high-quality that is applied to that advanced ceramics devices in batches produces, low cost, green polishing film preparation method is particularly necessary.
Summary of the invention
In order to realize, advanced ceramics device is efficient, high-quality, low cost, green are finished to target, the present invention proposes a kind of solubility set mild abrasives polishing film preparation method.Soft abrasive particle refers to that hardness of the abrasive grain is lower than part material hardness.
To achieve these goals, the technical solution used in the present invention is a kind of solubility set mild abrasives polishing film preparation method, adopt a kind of soluble high-molecular material as the bonding agent of soft fine abrasive, the soft fine abrasive that multilayer particle diameter is distributed is by a certain percentage coated in flexible film-substrate, form the mild abrasives layer of polishing film, this mild abrasives layer comprises following component, below all by mass percentage: bonding agent 10～30%, mild abrasives 50～60%, paraffin wax emulsion 1～5%, salt 3～10%, abrasive material modification dispersant 1～5%, each forms mass percent sum is 100%, when making polishing film, elder generation in water, makes the gluey aqueous solution in connection with agent stirring and dissolving, add again acid to stir 5～20 minutes, then add soft fine abrasive, paraffin wax emulsion, salt, stir 5～30 minutes, finally add formalin, stir 5～30 minutes, require the slurry after stirring to go out micro-pore foam, and keep certain mobility, the slurry being stirred is evenly laid in to film-substrate surface, is placed in insulating box, 50～80 ℃ of steady temperatures, temperature retention time 0.5～3 hour, drying and moulding,
The described soluble high-molecular material as bonding agent is: the salt of polyvinyl alcohol, PEO, alkyd resins, Lauxite, melamine resin, resol, polyacrylic acid or polymethylacrylic acid, one or more combination;
Described thin film substrate material is: polyester fiber cloth, flaxen fiber cloth, nonwoven, paper and cloth form complex matrix, carbon fibre resin material, polyethylene, polypropylene, senior a-olefin polymer, coumarone-indene resin, EP rubbers, butene rubber, neoprene, butadiene-styrene rubber, SBS thermoplastic elastomer (TPE), SAN, ABS resin, poly-the third ethene, polyvinyl chloride, politef, polyvinyl acetate, (methyl) acrylics.
Further, the mild abrasives that mild abrasives layer is used is: one or more of cerium oxide, silica, iron oxide, magnesia, chromium oxide, aluminium oxide, carborundum, by a certain percentage the mixing particle diameter abrasive material of preparation; Described abrasive hardness is lower than workpiece material hardness; Described abrasive material can with workpiece material generation solid phase reaction, realize the nearly not damaged of material and efficiently remove.
Further, the polishing fluid that described mild abrasives layer is used in process forms in proportion for deionized water or pure water, alcohol solvent.
Technical conceive of the present invention is: with a kind of water-soluble high-molecular material, if polyvinyl alcohol, PEO, alkyd resins etc. are as bonding agent, the soft fine abrasive of multilayer particle diameter, as silica, cerium oxide etc., will distribute according to certain rules and be coated in flexible substrate base.Small particle diameter abrasive particle can participate in polishing process directly, can be used as again filler, play the oarse-grained effect of supporting, reduce the resin-bonded agent content in polishing film, thereby effectively avoided producing the physical property such as contraction due to resinoid bond in existing film polishing grinding tool, changed the film surface be full of cracks causing, the problem collapsing out.In process, adopt described polishing fluid to dissolve the bonding agent on polishing film top layer, reducing bonding agent comes off it to the hold of abrasive particle, can remove top layer passivation abrasive particle on the one hand, expose new abrasive particle, realize the self refresh of polishing film Abrasive Grain, make polishing film have comparatively lasting polishing performance; On the other hand, anchor at the lip-deep abrasive particle of polishing film and be distributed to abrasive particle in polishing fluid to workpiece acting in conjunction with coming off, can realize the efficient polishing of workpiece super-smooth surface.Meanwhile, because bonding agent is dissolved, reduced the pollution of bonding agent to polished surface.
Meanwhile, in grinding tool, make the mild abrasives of stating can produce solid phase reaction with ceramic material workpiece in process, realize workpiece material and efficiently remove.This is that the atomic binding energy of ceramic material plane of crystal is certain distribution because workpiece (ceramic material crystal) surface exists planar defect.Therefore, although thereby the hardness of abrasive material makes its ideal crystal in conjunction with being less than ceramic material lower than ceramic material, and still the combination of some atom can be lower than the combination energy of abrasive surface atom for ceramic material surfaces.When abrasive particle streaks in ceramic material surfaces, because of machinery and hot effect, the atom phase counterdiffusion of abrasive particle and ceramic material surfaces, some abrasive material atom is clamp-oned ceramic material top layer, has more reduced the combination energy of ceramic material surfaces; When next abrasive particle streaks ceramic material surfaces, due to the reduction of ceramic material top layer atomic binding energy, material is easy to be removed.Therefore, rely on the chemical machinery effect producing between mild abrasives and ceramic material to realize the removal of material, its machining unit can reach atom level, thereby can obtain extremely low machined surface roughness.
The specific embodiment
Embodiment 1:
A solubility set mild abrasives polishing film preparation method, its structure as shown in Figure 1.Mild abrasives layer 1 is adopted with the following method and is made: to make 100 grams of mild abrasives layers, take abrasive material composition quality, as follows by mass percentage: bonding agent (polyvinyl alcohol) quality is 10～25%, mild abrasives is 50～60%, alditol quality is 1～5%, paraffin wax emulsion quality is 1～5%, salt quality is 3～10%, abrasive material modification dispersant 0.5～1%, each forms mass percent sum is 100%.Mild abrasives is selected as silica, and particle diameter specification is respectively 300nm, 100nm, 40nm.Mass ratio is 5:2:3.
Make flow process: first deionized water is put into reaction pot, under agitation add polyvinyl alcohol, heated constant temperature to 85～95 degree Celsius, make polyvinyl alcohol all be dissolved in water; 10 grams of hydrochloric acid that add concentration 20～30%, stir 10～20 minutes; Add the abrasive material, the alditol that have prepared, paraffin wax emulsion, salt, stir 20～30 minutes again; Adding concentration is 35～40% formalin again, stirs 20～30 minutes.Require the slurry after stirring to go out micro-pore foam, and keep certain mobility.
The slurry being stirred is poured in mould, and die sleeve inwall is brushed with one deck suds in advance, the film-substrate 2 (as materials such as nonwoven, polyethylene) that on base plate, thickness of liner is 0.1～1mm.Tiling slurry is on film-substrate 2 surfaces, and stand abrasive material thickness is 0.2～4mm.The stand uniform mould of material is put into constant temperature oven, and steady temperature is 50～80 degrees Celsius, temperature retention time 1～3 hour.Dry, mould unloading.
The polishing film that adopts said method to prepare, polishing monocrystalline silicon piece, load is 0.3MPa, grinding tool rotating speed 100r/Min, polishing fluid adopts deionized water.After polishing, silicon chip surface roughness finally reaches below 10nm, and unit interval workpiece material clearance reaches 11 microns.
Embodiment 2:
A solubility set mild abrasives polishing film preparation method, its structure as shown in Figure 1.Mild abrasives layer 1 is adopted with the following method: to make 100 grams of mild abrasives layers, take abrasive material composition as follows by mass percentage: bonding agent (alkyd resins) quality 12～20%, mild abrasives quality are 40～60%, alditol quality is 1～3%, paraffin wax emulsion quality is 1～5%, salt quality is 3～8%, abrasive material modification dispersant 0.5～1%.Abrasive material is cerium oxide, and particle diameter specification is respectively 50 μ m, 15 μ m, 5 μ m.Mass ratio is 6:2:2.
Make flow process: first deionized water is put into reaction pot, under agitation add alkyd resins, heated constant temperature to 85～95 degree Celsius, make alkyd resins all be dissolved in water; 10 grams of hydrochloric acid that add concentration 20～30%, stir 10～15 minutes; Add the abrasive material, the alditol that have prepared, paraffin wax emulsion, salt, stir 10～20 minutes again; Adding concentration is 35～40% formalin again, stirs 15～20 minutes.Require the slurry after stirring to go out micro-pore foam, and keep certain mobility.
The slurry being stirred is poured in mould, and die sleeve inwall is brushed with one deck suds in advance, the film-substrate 2 (as nonwoven, polyethylene etc.) that on base plate, thickness of liner is 0.1～1mm.Tiling slurry is on film-substrate 2 surfaces, and stand abrasive material thickness is 0.2～4mm.The stand uniform mould of material is put into constant temperature oven, and steady temperature is 50～80 degrees Celsius, temperature retention time 1～3 hour.Dry, mould unloading.
The polishing film that adopts said method to prepare, polishing of optical glass, load is 0.4MPa, grinding tool rotating speed 100r/Min, polishing fluid adopts deionized water.After polishing, optical lens surface roughness finally reaches below 10nm, and workpiece material clearance reaches 25 micro-ms/min.
Content described in this description embodiment is only enumerating the way of realization of inventive concept; protection scope of the present invention should not be regarded as only limiting to the concrete form that embodiment states, protection scope of the present invention also comprises that those skilled in the art conceive the equivalent technologies means that can expect according to the present invention.
Claims (3)
1. a solubility set mild abrasives polishing film preparation method, it is characterized in that: adopt a kind of soluble high-molecular material as the bonding agent of soft fine abrasive, the soft fine abrasive that multilayer particle diameter is distributed is by a certain percentage coated in flexible film-substrate, form the mild abrasives layer of polishing film, this mild abrasives layer comprises following component, below all by mass percentage: bonding agent 10～30%, mild abrasives 50～60%, paraffin wax emulsion 1～5%, salt 3～10%, abrasive material modification dispersant 1～5%, each forms mass percent sum is 100%, when making polishing film, elder generation in water, makes the gluey aqueous solution in connection with agent stirring and dissolving, add again acid to stir 5～20 minutes, then add soft fine abrasive, paraffin wax emulsion, salt, stir 5～30 minutes, finally add formalin, stir 5～30 minutes, require the slurry after stirring to go out micro-pore foam, and keep certain mobility, the slurry being stirred is evenly laid in to film-substrate surface, is placed in insulating box, 50～80 ℃ of steady temperatures, temperature retention time 0.5～3 hour, drying and moulding,
The described soluble high-molecular material as bonding agent is: the salt of polyvinyl alcohol, PEO, alkyd resins, Lauxite, melamine resin, resol, polyacrylic acid or polymethylacrylic acid, one or more combination;
Described film-substrate is: polyester fiber cloth, flaxen fiber cloth, nonwoven, paper and cloth form complex matrix, carbon fibre resin material, polyethylene, polypropylene, senior a-olefin polymer, coumarone-indene resin, EP rubbers, butene rubber, neoprene, butadiene-styrene rubber, SBS thermoplastic elastomer (TPE), SAN, ABS resin, poly-the third ethene, polyvinyl chloride, politef, polyvinyl acetate, (methyl) acrylics.
2. a kind of solubility set mild abrasives polishing film preparation method according to claim 1, it is characterized in that: the mild abrasives that described mild abrasives layer is used is: one or more of cerium oxide, silica, iron oxide, magnesia, chromium oxide, aluminium oxide, carborundum, by a certain percentage the mixing particle diameter abrasive material of preparation; Described abrasive hardness is lower than workpiece material hardness; Described abrasive material can with described workpiece material generation solid phase reaction, realize the nearly not damaged of material and efficiently remove.
3. a kind of solubility set mild abrasives polishing film preparation method according to claim 1, is characterized in that: the polishing fluid that described mild abrasives layer is used in process forms in proportion for deionized water or pure water, alcohol solvent.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410461448.3A CN104209879B (en) | 2014-09-11 | 2014-09-11 | Method for manufacturing soluble fixed soft abrasive-polishing film |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410461448.3A CN104209879B (en) | 2014-09-11 | 2014-09-11 | Method for manufacturing soluble fixed soft abrasive-polishing film |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN104209879A true CN104209879A (en) | 2014-12-17 |
| CN104209879B CN104209879B (en) | 2017-04-12 |
Family
ID=52091994
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201410461448.3A Expired - Fee Related CN104209879B (en) | 2014-09-11 | 2014-09-11 | Method for manufacturing soluble fixed soft abrasive-polishing film |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN104209879B (en) |
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106519475A (en) * | 2016-11-09 | 2017-03-22 | 蚌埠学院 | Slot milling technology of steel plate blank |
| CN106944939A (en) * | 2017-03-17 | 2017-07-14 | 衢州学院 | It is a kind of add soluble resin material from superhard fine grinding tool pellet of dressing and preparation method thereof |
| CN107141673A (en) * | 2017-03-27 | 2017-09-08 | 湖北丽尔家日用品股份有限公司 | A kind of PVA polished silicon wafers and preparation method thereof |
| CN110052917A (en) * | 2019-04-27 | 2019-07-26 | 安徽工程大学 | A kind of sapphire polishing processing method based on concretion abrasive technology |
| CN110405649A (en) * | 2019-08-05 | 2019-11-05 | 衢州学院 | A kind of collosol and gel polishing pellet and preparation method thereof of addition with waterproof coating soluble filler |
| CN110405543A (en) * | 2019-08-05 | 2019-11-05 | 衢州学院 | A kind of ferrite substrate polishing method using acid polishing slurry and Metal Substrate polishing disk |
| CN112959233A (en) * | 2021-03-05 | 2021-06-15 | 南京航空航天大学 | Fixed abrasive polishing pad and deliquescent KDP crystal dry-type polishing method |
| US11292102B2 (en) * | 2017-12-29 | 2022-04-05 | Saint-Gobain Abrasives, Inc. | Abrasive buffing articles |
Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1088505A (en) * | 1993-08-23 | 1994-06-29 | 中国工程物理研究院流体物理研究所 | Fixed abrasive polishing sheet |
| US5782675A (en) * | 1996-10-21 | 1998-07-21 | Micron Technology, Inc. | Apparatus and method for refurbishing fixed-abrasive polishing pads used in chemical-mechanical planarization of semiconductor wafers |
| CN1486234A (en) * | 2001-01-10 | 2004-03-31 | 3M | Wiping film |
| CN101148034A (en) * | 2007-11-06 | 2008-03-26 | 浙江工业大学 | Multi-level grain size abrasive grain mixed semi-fixation abrasive grain grinding tool |
| CN101148035A (en) * | 2007-11-06 | 2008-03-26 | 浙江工业大学 | Soft/hard abrasive grain mixed semi-fixation abrasive grain grinding tool |
| CN101157198A (en) * | 2007-10-31 | 2008-04-09 | 浙江工业大学 | Semi-sessile abrasive grain of plane stainless steel polishing method |
| CN101176983A (en) * | 2007-11-28 | 2008-05-14 | 浙江工业大学 | Semi-fixing abrasive grain polishing method of brass sheet substrate |
| CN102085644A (en) * | 2009-12-02 | 2011-06-08 | 中国砂轮企业股份有限公司 | Polishing belt with modified polyester substrate and preparation method thereof |
-
2014
- 2014-09-11 CN CN201410461448.3A patent/CN104209879B/en not_active Expired - Fee Related
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1088505A (en) * | 1993-08-23 | 1994-06-29 | 中国工程物理研究院流体物理研究所 | Fixed abrasive polishing sheet |
| US5782675A (en) * | 1996-10-21 | 1998-07-21 | Micron Technology, Inc. | Apparatus and method for refurbishing fixed-abrasive polishing pads used in chemical-mechanical planarization of semiconductor wafers |
| CN1486234A (en) * | 2001-01-10 | 2004-03-31 | 3M | Wiping film |
| CN101157198A (en) * | 2007-10-31 | 2008-04-09 | 浙江工业大学 | Semi-sessile abrasive grain of plane stainless steel polishing method |
| CN101148034A (en) * | 2007-11-06 | 2008-03-26 | 浙江工业大学 | Multi-level grain size abrasive grain mixed semi-fixation abrasive grain grinding tool |
| CN101148035A (en) * | 2007-11-06 | 2008-03-26 | 浙江工业大学 | Soft/hard abrasive grain mixed semi-fixation abrasive grain grinding tool |
| CN101176983A (en) * | 2007-11-28 | 2008-05-14 | 浙江工业大学 | Semi-fixing abrasive grain polishing method of brass sheet substrate |
| CN102085644A (en) * | 2009-12-02 | 2011-06-08 | 中国砂轮企业股份有限公司 | Polishing belt with modified polyester substrate and preparation method thereof |
Non-Patent Citations (1)
| Title |
|---|
| 李东光: "《抛光剂配方与生产》", 30 September 2012, 化学工业出版社 * |
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106519475A (en) * | 2016-11-09 | 2017-03-22 | 蚌埠学院 | Slot milling technology of steel plate blank |
| CN106519475B (en) * | 2016-11-09 | 2018-12-18 | 蚌埠学院 | A kind of groove milling technique of steel plate embryo material |
| CN106944939A (en) * | 2017-03-17 | 2017-07-14 | 衢州学院 | It is a kind of add soluble resin material from superhard fine grinding tool pellet of dressing and preparation method thereof |
| CN107141673A (en) * | 2017-03-27 | 2017-09-08 | 湖北丽尔家日用品股份有限公司 | A kind of PVA polished silicon wafers and preparation method thereof |
| US11292102B2 (en) * | 2017-12-29 | 2022-04-05 | Saint-Gobain Abrasives, Inc. | Abrasive buffing articles |
| CN110052917A (en) * | 2019-04-27 | 2019-07-26 | 安徽工程大学 | A kind of sapphire polishing processing method based on concretion abrasive technology |
| CN110405649A (en) * | 2019-08-05 | 2019-11-05 | 衢州学院 | A kind of collosol and gel polishing pellet and preparation method thereof of addition with waterproof coating soluble filler |
| CN110405543A (en) * | 2019-08-05 | 2019-11-05 | 衢州学院 | A kind of ferrite substrate polishing method using acid polishing slurry and Metal Substrate polishing disk |
| CN112959233A (en) * | 2021-03-05 | 2021-06-15 | 南京航空航天大学 | Fixed abrasive polishing pad and deliquescent KDP crystal dry-type polishing method |
Also Published As
| Publication number | Publication date |
|---|---|
| CN104209879B (en) | 2017-04-12 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN104209879A (en) | Method for manufacturing soluble fixed soft abrasive-polishing film | |
| CN101451046B (en) | Polishing composition for silicon wafer polishing | |
| JP6586963B2 (en) | Ultrafine abrasive biopolymer flexible polishing film and method for producing the same | |
| CN100425405C (en) | Freezing nanometer abrasive polishing pad and its prepn. method | |
| JP6317842B1 (en) | Polishing pad and manufacturing method thereof | |
| CN101367189A (en) | Silicon slice glazed surface scuffing control method | |
| CN102516876A (en) | Polishing composition for silicon wafer polishing and preparation method thereof | |
| JP2016537439A (en) | Ceramic abrasive composite polishing solution | |
| CN101096080A (en) | Solidified abrasive lapping polishing pad having self-modifying function and preparation method | |
| JPWO2008117883A1 (en) | Synthetic whetstone | |
| CN100500375C (en) | Semi-sessile abrasive grain polishing method of plane stainless steel | |
| JP2017530210A (en) | Polishing liquid and method of using the same | |
| CN109880533A (en) | A kind of composite abrasive grain polishing solution and preparation method thereof | |
| CN104465363B (en) | A kind of single-crystal silicon carbide piece cmp method of utilization synthetic resin tin disk | |
| CN102059640B (en) | Method for polishing semiconductor wafer | |
| CN106147614A (en) | Hard ceramic polishing fluid and preparation method thereof | |
| CN105690240B (en) | A kind of flexible polishing pad | |
| Li et al. | Fixed abrasive lapping and polishing of hard brittle materials | |
| JP2006315110A (en) | Abrasive material, manufacturing method and polishing method | |
| JP2000301459A (en) | Grinding tool and polishing method using it | |
| CN101367194A (en) | Silicon slice grinding rate control method | |
| CN104227509A (en) | Soluble setting soft abrasive particle thin film polishing method of optical fiber connector | |
| CN109913133A (en) | A kind of high-effect high-quality chemical mechanical polishing liquid of yag crystal | |
| CN104479558B (en) | A kind of silicon wafer precise polishing solution that can extend polishing pad service life | |
| JP4167441B2 (en) | Abrasive and carrier particles |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20170412 Termination date: 20180911 |