CN108484178A - 一种水溶性陶瓷型芯增塑剂的制备方法及其应用 - Google Patents
一种水溶性陶瓷型芯增塑剂的制备方法及其应用 Download PDFInfo
- Publication number
- CN108484178A CN108484178A CN201810171256.7A CN201810171256A CN108484178A CN 108484178 A CN108484178 A CN 108484178A CN 201810171256 A CN201810171256 A CN 201810171256A CN 108484178 A CN108484178 A CN 108484178A
- Authority
- CN
- China
- Prior art keywords
- ceramic core
- plasticizer
- water
- batch mixer
- ldpe
- 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
Classifications
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
- C04B35/622—Forming processes; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
- C04B35/626—Preparing or treating the powders individually or as batches ; preparing or treating macroscopic reinforcing agents for ceramic products, e.g. fibres; mechanical aspects section B
- C04B35/63—Preparing or treating the powders individually or as batches ; preparing or treating macroscopic reinforcing agents for ceramic products, e.g. fibres; mechanical aspects section B using additives specially adapted for forming the products, e.g.. binder binders
- C04B35/632—Organic additives
- C04B35/634—Polymers
- C04B35/63448—Polymers obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds
- C04B35/63488—Polyethers, e.g. alkylphenol polyglycolether, polyethylene glycol [PEG], polyethylene oxide [PEO]
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22C—FOUNDRY MOULDING
- B22C1/00—Compositions of refractory mould or core materials; Grain structures thereof; Chemical or physical features in the formation or manufacture of moulds
- B22C1/02—Compositions of refractory mould or core materials; Grain structures thereof; Chemical or physical features in the formation or manufacture of moulds characterised by additives for special purposes, e.g. indicators, breakdown additives
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
- C04B35/622—Forming processes; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
- C04B35/622—Forming processes; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
- C04B35/626—Preparing or treating the powders individually or as batches ; preparing or treating macroscopic reinforcing agents for ceramic products, e.g. fibres; mechanical aspects section B
- C04B35/63—Preparing or treating the powders individually or as batches ; preparing or treating macroscopic reinforcing agents for ceramic products, e.g. fibres; mechanical aspects section B using additives specially adapted for forming the products, e.g.. binder binders
- C04B35/632—Organic additives
- C04B35/634—Polymers
- C04B35/63404—Polymers obtained by reactions only involving carbon-to-carbon unsaturated bonds
- C04B35/63408—Polyalkenes
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
- C04B35/622—Forming processes; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
- C04B35/64—Burning or sintering processes
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B38/00—Porous mortars, concrete, artificial stone or ceramic ware; Preparation thereof
- C04B38/04—Porous mortars, concrete, artificial stone or ceramic ware; Preparation thereof by dissolving-out added substances
Abstract
本发明涉及一种陶瓷型芯增塑剂的制备方法,其目的在于一方面要解决现有的陶瓷型芯增塑剂烧成周期长、表面易产生鼓包、裂纹、流痕及污染环境问题;另一面是如何采用上述制备的增塑剂来制备新型的陶瓷型芯。增塑剂的制备:取聚乙二醇、聚丙烯纤维、低密度聚乙烯,先将混料机升温后加入低密度聚乙烯并搅拌,待其完全熔化后,将混料机温度降后加入聚乙二醇并搅拌熔化均匀,最后加入聚丙烯纤维,上述原料在混料机中搅拌4h,制得水溶性陶瓷型芯增塑剂,然后取出待用。其应用:称取水溶性增塑剂15‑18%,陶瓷型芯基体粉料85‑82%,经压制、溶解脱除等步骤得到多孔陶瓷型芯生坯,然后经焙烧得到陶瓷型芯。主要应用于熔模精密铸造技术领域。
Description
技术领域
本发明涉及一种陶瓷型芯增塑剂的制备方法以及采用此种增塑剂的陶瓷型芯的制备方法,主要应用于熔模精密铸造技术领域。
背景技术
陶瓷型芯作为形成精铸件空心内腔结构的转接件,其作用是:形成精铸件的内腔形状,并与外形模及模壳共同保证精铸件壁厚的尺寸精度。陶瓷型芯是将选定的基体材料和增塑剂,在加热状态下搅拌配成均匀的热塑性浆料,然后在专用设备上以某种方式按照所需形状和尺寸压制成型芯试样或零件生坯。为了使浆料的成形性能满足工艺要求,陶瓷型芯配料体系中增塑剂的含量一般为20%左右。增塑剂一般会通过高温烧成工艺排出(这一工序称为排蜡)。该工艺主要存在以下问题:(1)时间长,一般排蜡阶段的时间为10h以上,排蜡阶段的升温速度不能超过1℃/min;(2)排蜡过程中极易由于排蜡通道不畅,在陶瓷型芯表面产生鼓包、裂纹、流痕等缺陷;(3)排蜡过程产生大量蜡烟污染环境。
发明内容
鉴于此,本发明的目的在于一方面要解决上述现有的陶瓷型芯增塑剂存在的技术问题,而提供一种可将烧成排蜡变为水溶排蜡的技术方案;另一面是如何采用上述制备的增塑剂来制备新型的陶瓷型芯。
为实现上述目的,本发明采用的技术方案是:
1、制备水溶性陶瓷型芯增塑剂
按重量比例称取:聚乙二醇(PEG4000:PEG6000:PEG8000=2:7:1)80-85%,聚丙烯纤维1-2%,低密度聚乙烯10-20%。首先将混料机升温到120℃,然后加入低密度聚乙烯并搅拌,待其完全熔化后,将混料机温度降至90℃,然后加入聚乙二醇并搅拌熔化均匀,最后加入聚丙烯纤维,上述原料在混料机中,90℃下搅拌4h,制得水溶性陶瓷型芯增塑剂,然后取出待用;
2、上述水溶性陶瓷型芯增塑剂在制备陶瓷型芯中的应用
首先,按重量比例称取:水溶性增塑剂15-18%,陶瓷型芯基体粉料85-82%。采用常规工艺制备陶瓷型芯浆料并压制陶瓷型芯生坯。陶瓷型芯生坯从模具中取出后浸没入室温水中,将坯体中的聚乙二醇溶解脱除(坯体在水中的浸泡时间由陶瓷型芯的具体结构特点决定),得到以聚乙烯等为支撑骨架的多孔陶瓷型芯生坯。然后将其埋入氧化铝粉中焙烧。由于大部分增塑剂已经水溶脱除,因此可以将排蜡时间缩短至5小时以内,升温速度3-3.5℃/min。烧成温度为1200-1250℃,保温时间为2-4h。烧成完毕后,随炉冷却至200℃,打开炉门,冷却至60℃以下方可出窑得到陶瓷型芯。
本发明的特点及有益效果:
本发明能够显著缩短烧成周期,弥补了现有技术排蜡过程中容易在陶瓷型芯表面产生鼓包、裂纹、流痕等缺陷,并且由于大部分增塑剂已经通过水溶脱除,烧成过程中仅有少量蜡烟排出,可显著减少对环境的污染。
具体实施方式
实施例一
按重量比例称取:聚乙二醇(PEG4000:PEG6000:PEG8000=2:7:1)80%,聚丙烯纤维1%,低密度聚乙烯19%。首先将混料机升温到120℃,然后加入低密度聚乙烯并搅拌,待其完全熔化后,将混料机温度降至90℃,然后加入聚乙二醇并搅拌熔化均匀,最后加入聚丙烯纤维,上述原料在混料机中,90℃下搅拌4h,制得水溶性陶瓷型芯增塑剂,然后取出待用。
实施例二
按重量比例称取:聚乙二醇(PEG4000:PEG6000:PEG8000=2:7:1)85%,聚丙烯纤维2%,低密度聚乙烯13%。首先将混料机升温到120℃,然后加入低密度聚乙烯并搅拌,待其完全熔化后,将混料机温度降至90℃,然后加入聚乙二醇并搅拌熔化均匀,最后加入聚丙烯纤维,上述原料在混料机中,90℃下搅拌4h,制得水溶性陶瓷型芯增塑剂,然后取出待用;
实施例三
按重量比例称取:聚乙二醇(PEG4000:PEG6000:PEG8000=2:7:1)82%,聚丙烯纤维1.5%,低密度聚乙烯16.5%。首先将混料机升温到120℃,然后加入低密度聚乙烯并搅拌,待其完全熔化后,将混料机温度降至90℃,然后加入聚乙二醇并搅拌熔化均匀,最后加入聚丙烯纤维,上述原料在混料机中,90℃下搅拌4h,制得水溶性陶瓷型芯增塑剂,然后取出待用;
分别采用上述三个实例中的水溶性增塑剂配料应用于制备陶瓷型芯。具体工艺如下:按重量比例称取:水溶性增塑剂15-18%,陶瓷型芯基体粉料85-82%。采用常规工艺制备陶瓷型芯浆料并压制陶瓷型芯生坯。陶瓷型芯生坯从模具中取出后浸没入室温水中,将坯体中的聚乙二醇溶解脱除(坯体在水中的浸泡时间由陶瓷型芯的具体结构特点决定),得到以聚乙烯等为支撑骨架的多孔陶瓷型芯生坯。然后将其埋入氧化铝粉中焙烧。升温速度3-3.5℃/min,烧成温度为1200-1250℃,保温时间为2-4h。烧成完毕后,随炉冷却至200℃,打开炉门,冷却至60℃以下出窑得到陶瓷型芯。
Claims (5)
1.一种水溶性陶瓷型芯增塑剂的制备方法,其特征在于:按重量比例称取:聚乙二醇80-85%;聚丙烯纤维1-2%;低密度聚乙烯10-20%,首先将混料机升温到120℃,然后加入低密度聚乙烯并搅拌,待其完全熔化后,将混料机温度降至90℃,然后加入聚乙二醇并搅拌熔化均匀,最后加入聚丙烯纤维,上述原料在混料机中,90℃下搅拌4h,制得水溶性陶瓷型芯增塑剂,然后取出待用。
2.如权利要求1所述的水溶性陶瓷型芯增塑剂的制备方法,其特征在于该制备方法是通过下述具体步骤实现的:
按重量比例称取:聚乙二醇80%,聚丙烯纤维1%,低密度聚乙烯19%,首先将混料机升温到120℃,然后加入低密度聚乙烯并搅拌,待其完全熔化后,将混料机温度降至90℃,然后加入聚乙二醇并搅拌熔化均匀,最后加入聚丙烯纤维,上述原料在混料机中,90℃下搅拌4h,制得水溶性陶瓷型芯增塑剂,然后取出待用。
3.如权利要求1所述的水溶性陶瓷型芯增塑剂的制备方法,其特征在于该制备方法是通过下述具体步骤实现的:
按重量比例称取:聚乙二醇85%,聚丙烯纤维2%,低密度聚乙烯13%,首先将混料机升温到120℃,然后加入低密度聚乙烯并搅拌,待其完全熔化后,将混料机温度降至90℃,然后加入聚乙二醇并搅拌熔化均匀,最后加入聚丙烯纤维,上述原料在混料机中,90℃下搅拌4h,制得水溶性陶瓷型芯增塑剂,然后取出待用;
4.如权利要求1所述的水溶性陶瓷型芯增塑剂的制备方法,其特征在于该制备方法是通过下述具体步骤实现的:
按重量比例称取:聚乙二醇82%,聚丙烯纤维1.5%,低密度聚乙烯16.5%,首先将混料机升温到120℃,然后加入低密度聚乙烯并搅拌,待其完全熔化后,将混料机温度降至90℃,然后加入聚乙二醇并搅拌熔化均匀,最后加入聚丙烯纤维,上述原料在混料机中,90℃下搅拌4h,制得水溶性陶瓷型芯增塑剂,然后取出待用;
5.采用如权利要求1或2或3或4方法制备的水溶性陶瓷型芯增塑剂的应用,首先,按重量比例称取:水溶性增塑剂15-18%,陶瓷型芯基体粉料85-82%,采用常规工艺制备陶瓷型芯浆料并压制陶瓷型芯生坯,陶瓷型芯生坯从模具中取出后浸没入室温水中,将坯体中的聚乙二醇溶解脱除,得到以聚乙烯等为支撑骨架的多孔陶瓷型芯生坯,然后将其埋入氧化铝粉中焙烧,由于大部分增塑剂已经水溶脱除,因此可以将排蜡时间缩短至5小时以内,升温速度3-3.5℃/min,烧成温度为1200-1250℃,保温时间为2-4h,烧成完毕后,随炉冷却至200℃,打开炉门,冷却至60℃以下方可出窑得到陶瓷型芯。
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
CN201810171256.7A CN108484178A (zh) | 2018-03-01 | 2018-03-01 | 一种水溶性陶瓷型芯增塑剂的制备方法及其应用 |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
CN201810171256.7A CN108484178A (zh) | 2018-03-01 | 2018-03-01 | 一种水溶性陶瓷型芯增塑剂的制备方法及其应用 |
Publications (1)
Publication Number | Publication Date |
---|---|
CN108484178A true CN108484178A (zh) | 2018-09-04 |
Family
ID=63340916
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
CN201810171256.7A Pending CN108484178A (zh) | 2018-03-01 | 2018-03-01 | 一种水溶性陶瓷型芯增塑剂的制备方法及其应用 |
Country Status (1)
Country | Link |
---|---|
CN (1) | CN108484178A (zh) |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
RU2760139C1 (ru) * | 2021-04-26 | 2021-11-22 | Акционерное общество «ОДК-Авиадвигатель» | Способ изготовления керамических стержней в литье по выплавляемым моделям с использованием самотвердеющих смесей (варианты) |
RU2760460C1 (ru) * | 2021-04-26 | 2021-11-25 | Акционерное общество «ОДК-Авиадвигатель» | Способ изготовления безобжиговых керамических стержней в литье по выплавляемым моделям с использованием самотвердеющих смесей (варианты) |
Citations (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN1792498A (zh) * | 2005-11-29 | 2006-06-28 | 辽宁省轻工科学研究院 | 空心陶瓷型芯的制备方法 |
CN103286273A (zh) * | 2011-12-13 | 2013-09-11 | 丹阳市精密合金厂有限公司 | 机匣类环形铸件空心支板成型用陶瓷型芯的制备方法 |
CN104086161A (zh) * | 2014-04-29 | 2014-10-08 | 中国科学院金属研究所 | 一种可调节热膨胀系数的硅基陶瓷型芯的制备方法 |
US20150239037A1 (en) * | 2012-10-25 | 2015-08-27 | Beihang University | Calcium oxide-based ceramic core and preparation method thereof |
CN104907492A (zh) * | 2015-05-07 | 2015-09-16 | 西安交通大学 | 一种面向双层壁空心涡轮叶片的制造方法 |
CN105016725A (zh) * | 2015-07-24 | 2015-11-04 | 深圳市亿达光电技术有限公司 | 一种陶瓷插芯专用陶瓷颗粒及其制备方法 |
CN106977184A (zh) * | 2017-03-14 | 2017-07-25 | 深圳市星迪伟业科技有限公司 | 一种陶瓷零件及其生产工艺 |
CN107042309A (zh) * | 2017-03-07 | 2017-08-15 | 长沙理工大学 | 一种水溶性型芯部件及其制备方法 |
-
2018
- 2018-03-01 CN CN201810171256.7A patent/CN108484178A/zh active Pending
Patent Citations (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN1792498A (zh) * | 2005-11-29 | 2006-06-28 | 辽宁省轻工科学研究院 | 空心陶瓷型芯的制备方法 |
CN103286273A (zh) * | 2011-12-13 | 2013-09-11 | 丹阳市精密合金厂有限公司 | 机匣类环形铸件空心支板成型用陶瓷型芯的制备方法 |
US20150239037A1 (en) * | 2012-10-25 | 2015-08-27 | Beihang University | Calcium oxide-based ceramic core and preparation method thereof |
CN104086161A (zh) * | 2014-04-29 | 2014-10-08 | 中国科学院金属研究所 | 一种可调节热膨胀系数的硅基陶瓷型芯的制备方法 |
CN104907492A (zh) * | 2015-05-07 | 2015-09-16 | 西安交通大学 | 一种面向双层壁空心涡轮叶片的制造方法 |
CN105016725A (zh) * | 2015-07-24 | 2015-11-04 | 深圳市亿达光电技术有限公司 | 一种陶瓷插芯专用陶瓷颗粒及其制备方法 |
CN107042309A (zh) * | 2017-03-07 | 2017-08-15 | 长沙理工大学 | 一种水溶性型芯部件及其制备方法 |
CN106977184A (zh) * | 2017-03-14 | 2017-07-25 | 深圳市星迪伟业科技有限公司 | 一种陶瓷零件及其生产工艺 |
Non-Patent Citations (2)
Title |
---|
刘文等: "《药用高分子材料学》", 30 June 2017, 中国中医药出版社 * |
王程成等: ""注射成型水溶性陶瓷型芯技术"", 《航空材料学报》 * |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
RU2760139C1 (ru) * | 2021-04-26 | 2021-11-22 | Акционерное общество «ОДК-Авиадвигатель» | Способ изготовления керамических стержней в литье по выплавляемым моделям с использованием самотвердеющих смесей (варианты) |
RU2760460C1 (ru) * | 2021-04-26 | 2021-11-25 | Акционерное общество «ОДК-Авиадвигатель» | Способ изготовления безобжиговых керамических стержней в литье по выплавляемым моделям с использованием самотвердеющих смесей (варианты) |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
CN105732014B (zh) | 一种硅基陶瓷型芯制备方法 | |
CN102603275B (zh) | 硅基陶瓷型芯的制备方法 | |
CN105198449B (zh) | 一种光固化成型的高致密陶瓷的制备方法 | |
CN1326803C (zh) | 一种空心铸件陶瓷型芯及其制备方法 | |
US9603683B2 (en) | Method for producing a dental restoration by CAD casting | |
CN103360079B (zh) | 一种空心涡轮叶片一体化陶瓷铸型的型芯型壳定制方法 | |
CN109734425A (zh) | 一种复相陶瓷铸型的激光选区快速成型方法及其产品 | |
CN109734430A (zh) | 一种适用于双层壁叶片的多孔硅基陶瓷型芯及其制备方法 | |
CN108484178A (zh) | 一种水溶性陶瓷型芯增塑剂的制备方法及其应用 | |
WO2013018393A1 (ja) | セラミック中子およびその製造方法 | |
CN104043770B (zh) | 一种烧结陶瓷型芯用填料粉 | |
CN101429023A (zh) | 采用无机纤维复合的氧化锆陶瓷型芯材料 | |
CN102266906B (zh) | 一种易脱除陶瓷型芯的制备方法 | |
CN108275988A (zh) | 一种改进的硅基陶瓷型芯制备方法 | |
CN105732007B (zh) | 一种用于复杂零件制造的氧化钙基陶瓷铸型快速制备方法 | |
CN104692782B (zh) | 一种利用废料制作陶瓷型芯的方法 | |
US4591385A (en) | Die material and method of using same | |
CN106083005B (zh) | 高孔隙率易脱除硅基陶瓷型芯制备方法 | |
CN106007757A (zh) | 一种添加氧化铝纤维的氧化硅陶瓷型芯及其制备方法 | |
CN108188345A (zh) | 一种齿圈的成型方法 | |
CN113149671A (zh) | 轻质莫来石-氧化铝空心球-钛酸铝匣钵浇注成型工艺 | |
CN105884339A (zh) | 一种凝胶注模成型技术制备氧化铝直孔型供气元件的方法 | |
CN112047726A (zh) | 定向凝固用莫来石晶须增强铝基陶瓷型芯制备方法 | |
CN109928739A (zh) | 一种高温下高尺寸稳定性的硅基陶瓷型芯的制备方法 | |
CN106396342B (zh) | 制备玻璃测试样品的方法 |
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 | ||
WD01 | Invention patent application deemed withdrawn after publication |
Application publication date: 20180904 |
|
WD01 | Invention patent application deemed withdrawn after publication |