CN109049868A - 一种纳米纤维复合隔音材料 - Google Patents
一种纳米纤维复合隔音材料 Download PDFInfo
- Publication number
- CN109049868A CN109049868A CN201810720091.4A CN201810720091A CN109049868A CN 109049868 A CN109049868 A CN 109049868A CN 201810720091 A CN201810720091 A CN 201810720091A CN 109049868 A CN109049868 A CN 109049868A
- Authority
- CN
- China
- Prior art keywords
- sound
- layer
- complex
- insulation layer
- puigging
- 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- Withdrawn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
- 239000002121 nanofiber Substances 0.000 title claims abstract description 31
- 239000002131 composite material Substances 0.000 title claims abstract description 30
- 239000000463 material Substances 0.000 title claims abstract description 21
- 238000009413 insulation Methods 0.000 claims abstract description 31
- 230000030279 gene silencing Effects 0.000 claims abstract description 21
- 239000000835 fiber Substances 0.000 claims abstract description 15
- 239000010410 layer Substances 0.000 claims description 56
- 239000002344 surface layer Substances 0.000 claims description 13
- 239000004744 fabric Substances 0.000 claims description 6
- 238000000034 method Methods 0.000 claims description 6
- 238000010041 electrostatic spinning Methods 0.000 claims description 5
- 239000004626 polylactic acid Substances 0.000 claims description 5
- 239000011162 core material Substances 0.000 claims description 4
- 229920000747 poly(lactic acid) Polymers 0.000 claims description 4
- 239000004632 polycaprolactone Substances 0.000 claims description 4
- 239000004640 Melamine resin Substances 0.000 claims description 3
- 229920000877 Melamine resin Polymers 0.000 claims description 3
- 239000004698 Polyethylene Substances 0.000 claims description 3
- 230000001054 cortical effect Effects 0.000 claims description 3
- 239000006261 foam material Substances 0.000 claims description 3
- 238000000465 moulding Methods 0.000 claims description 3
- 229920001610 polycaprolactone Polymers 0.000 claims description 3
- -1 polyethylene Polymers 0.000 claims description 3
- 229920000573 polyethylene Polymers 0.000 claims description 3
- 239000002994 raw material Substances 0.000 claims description 3
- 239000004745 nonwoven fabric Substances 0.000 claims description 2
- 238000010521 absorption reaction Methods 0.000 abstract description 10
- 230000000694 effects Effects 0.000 abstract description 6
- 230000008030 elimination Effects 0.000 abstract description 3
- 238000003379 elimination reaction Methods 0.000 abstract description 3
- 239000012814 acoustic material Substances 0.000 description 5
- 238000010586 diagram Methods 0.000 description 3
- 230000008901 benefit Effects 0.000 description 2
- 229910052500 inorganic mineral Inorganic materials 0.000 description 2
- 239000011707 mineral Substances 0.000 description 2
- 239000004033 plastic Substances 0.000 description 2
- 229920003023 plastic Polymers 0.000 description 2
- 238000002360 preparation method Methods 0.000 description 2
- 240000007594 Oryza sativa Species 0.000 description 1
- 235000007164 Oryza sativa Nutrition 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 239000006071 cream Substances 0.000 description 1
- 238000013016 damping Methods 0.000 description 1
- 239000003814 drug Substances 0.000 description 1
- 230000005684 electric field Effects 0.000 description 1
- 230000005686 electrostatic field Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- 238000005098 hot rolling Methods 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 239000002086 nanomaterial Substances 0.000 description 1
- 239000002070 nanowire Substances 0.000 description 1
- 230000001473 noxious effect Effects 0.000 description 1
- 239000010451 perlite Substances 0.000 description 1
- 235000019362 perlite Nutrition 0.000 description 1
- 229920000642 polymer Polymers 0.000 description 1
- 239000000843 powder Substances 0.000 description 1
- 235000009566 rice Nutrition 0.000 description 1
- 238000007789 sealing Methods 0.000 description 1
- 239000002904 solvent Substances 0.000 description 1
- 238000009987 spinning Methods 0.000 description 1
- 239000012209 synthetic fiber Substances 0.000 description 1
- 229920002994 synthetic fiber Polymers 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
- 238000003911 water pollution Methods 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B27/00—Layered products comprising a layer of synthetic resin
- B32B27/06—Layered products comprising a layer of synthetic resin as the main or only constituent of a layer, which is next to another layer of the same or of a different material
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B27/00—Layered products comprising a layer of synthetic resin
- B32B27/42—Layered products comprising a layer of synthetic resin comprising condensation resins of aldehydes, e.g. with phenols, ureas or melamines
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B3/00—Layered products comprising a layer with external or internal discontinuities or unevennesses, or a layer of non-planar shape; Layered products comprising a layer having particular features of form
- B32B3/26—Layered products comprising a layer with external or internal discontinuities or unevennesses, or a layer of non-planar shape; Layered products comprising a layer having particular features of form characterised by a particular shape of the outline of the cross-section of a continuous layer; characterised by a layer with cavities or internal voids ; characterised by an apertured layer
- B32B3/266—Layered products comprising a layer with external or internal discontinuities or unevennesses, or a layer of non-planar shape; Layered products comprising a layer having particular features of form characterised by a particular shape of the outline of the cross-section of a continuous layer; characterised by a layer with cavities or internal voids ; characterised by an apertured layer characterised by an apertured layer, the apertures going through the whole thickness of the layer, e.g. expanded metal, perforated layer, slit layer regular cells B32B3/12
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B5/00—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts
- B32B5/02—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts characterised by structural features of a fibrous or filamentary layer
-
- G—PHYSICS
- G10—MUSICAL INSTRUMENTS; ACOUSTICS
- G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
- G10K11/00—Methods or devices for transmitting, conducting or directing sound in general; Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
- G10K11/16—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
- G10K11/162—Selection of materials
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B2262/00—Composition or structural features of fibres which form a fibrous or filamentary layer or are present as additives
- B32B2262/02—Synthetic macromolecular fibres
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B2262/00—Composition or structural features of fibres which form a fibrous or filamentary layer or are present as additives
- B32B2262/02—Synthetic macromolecular fibres
- B32B2262/0253—Polyolefin fibres
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B2307/00—Properties of the layers or laminate
- B32B2307/10—Properties of the layers or laminate having particular acoustical properties
- B32B2307/102—Insulating
Landscapes
- Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Acoustics & Sound (AREA)
- Multimedia (AREA)
- Nonwoven Fabrics (AREA)
- Laminated Bodies (AREA)
Abstract
本发明公开了一种纳米纤维复合隔音材料，包括消声层、复合隔音层和吸音层，消声层、复合隔音层和吸音层复合叠加在一起，复合隔音层位于中间；所述复合隔音层由相互叠加在一起的第一单隔音层和第二单隔音层组成，所述第一单隔音层和第二单隔音层的结构相同，均包括复合纤维层和纳米纤维层。本发明的复合隔音层对500Hz声源的吸收系数达到0.3以上，对1000Hz 声源的吸收系数达到0.6以上，吸音性能较好；且通过消声层和吸音层的设置，声波进入到消声层时，和无数的相互连通的孔洞壁摩擦，使声能转化为热能消化掉，从而起到消声作用，吸音层的结构使得它与声波的接触面积增大，具有更好的吸音效果。
Description
技术领域
本发明涉及纳米材料技术领域，具体是一种纳米纤维复合隔音材料。
背景技术
噪音污染已成为当代全球性的环境问题，与大气污染，水污染和固体废弃物污染一起被列为世界四大污染。随着经济及科技的发展，农业、工业越来越趋向机械化，交通运输业也日趋发达，但与此同时，噪音污染也越来越严重。人们对吸音隔音材料的需求越来越大，对其性能的要求也越来越高，特别是在建筑以及汽车领域，吸音隔音材料的市场不断发展壮大。汽车隔音产品在汽车领域的主要作用是隔音、减振、保暖。隔音产品所用的主体原料为各种天然纤维或者合成纤维，再加入部分热熔粉或热熔纤维加工而成。但是这种隔音毡吸音、隔音效果一般。而隔音材料在建筑工程中的应用主要在隔音板、隔音墙、密封圈等，常用膨胀珍珠岩、矿物纤维、泡沫塑料等材料。传统吸音隔音材料多为微米级的热熔纤维、矿物纤维以及泡沫塑料等，其孔洞较大，不利于吸音隔音材料对低频区噪音的吸收，限制了相关隔音产品的推广使用。
静电纺丝是一种简单、灵活的制备纤维直径为几十到几百纳米的纺丝方法，其基本原理是：毛细管出口的聚合物溶液或熔体，以及自由表面的液体局部点在高压静电场的作用下，变形成为泰勒锥，当静电排斥力超过液滴的表面张力时，泰勒锥的顶端处就会形成细流，并在电场的运动中得到进一步拉伸，同时随着溶剂挥发(或者熔体冷却)，得到纳米纤维。通过静电纺丝得到的纳米纤维有着极小的直径、高孔隙率、极大的比表面积以及潜在的优秀过滤效率等优点，这些特性使纳米纤维在生物医药、军工、过滤、降噪领域有着重要用途。
发明内容
本发明的目的在于提供一种纳米纤维复合隔音材料，以解决上述背景技术中提出的问题。
为实现上述目的，本发明提供如下技术方案：
一种纳米纤维复合隔音材料，包括消声层、复合隔音层和吸音层，消声层、复合隔音层和吸音层复合叠加在一起，复合隔音层位于中间；所述复合隔音层由相互叠加在一起的第一单隔音层和第二单隔音层组成，所述第一单隔音层和第二单隔音层的结构相同，均包括复合纤维层和纳米纤维层。
作为本发明进一步的方案：所述消声层和吸音层均为三聚氰胺树脂泡沫材料制成的多孔结构。
作为本发明进一步的方案：所述消声层背向复合隔音层的一侧表面设置有第一面层；所述吸音层背向复合隔音层的一侧表面设置有第二面层。
作为本发明进一步的方案：所述第一面层和第二面层均采用复合聚乙烯热轧无纺布制成。
作为本发明进一步的方案：所述复合纤维层的皮层材料为聚乳酸，芯层材料为聚己内酯，且为偏心结构，复合纤维层采用双螺杆工艺制得，通过纺粘形成非织造布，厚度为3mm。
作为本发明进一步的方案：所述纳米纤维层采用针头静电纺丝成型制得，以聚乳酸作为纳米纤维成纤原料，纳米纤维直径为200-800nm。
与现有技术相比，本发明的有益效果是：
本发明的复合隔音层对500Hz声源的吸收系数达到0.3以上，对1000Hz 声源的吸收系数达到0.6以上，吸音性能较好；且通过消声层和吸音层的设置，声波进入到消声层时，和无数的相互连通的孔洞壁摩擦，使声能转化为热能消化掉，从而起到消声作用，吸音层的结构使得它与声波的接触面积增大，具有更好的吸音效果。
附图说明
图1为一种纳米纤维复合隔音材料的结构示意图。
图2为一种纳米纤维复合隔音材料中复合隔音层的结构示意图。
图3为一种纳米纤维复合隔音材料中单隔音层的结构示意图。
图中：1-消声层，2-复合隔音，3-吸音层，4-第一面层，5-第二面层，21-第一单隔音层，22-第二单隔音层，211-复合纤维层，212-纳米纤维层。
具体实施方式
下面将结合本发明实施例中的附图，对本发明实施例中的技术方案进行清楚、完整地描述，显然，所描述的实施例仅仅是本发明一部分实施例，而不是全部的实施例。基于本发明中的实施例，本领域普通技术人员在没有做出创造性劳动前提下所获得的所有其他实施例，都属于本发明保护的范围。
请参阅图1～3，本发明实施例中，一种纳米纤维复合隔音材料，包括消声层1、复合隔音层2和吸音层3，消声层1、复合隔音层2和吸音层3复合叠加在一起，复合隔音层2位于中间，消声层1和吸音层3均为三聚氰胺树脂泡沫材料制成的多孔结构。
所述消声层1背向复合隔音层2的一侧表面设置有第一面层4，；所述吸音层3背向复合隔音层2的一侧表面设置有第二面层5；所述第一面层4和第二面层5均采用复合聚乙烯热轧无纺布制成。
所述复合隔音层2由相互叠加在一起的第一单隔音层21和第二单隔音层22组成，所述第一单隔音层21和第二单隔音层22的结构相同，均包括复合纤维层211和纳米纤维层212，所述复合纤维层211的皮层材料为聚乳酸(PLA)，芯层材料为聚己内酯 (PCL)，且为偏心结构，复合纤维层211采用双螺杆工艺制得，通过纺粘形成非织造布，厚度为3mm；所述纳米纤维层212采用针头静电纺丝成型制得，以聚乳酸作为纳米纤维成纤原料，纳米纤维直径为200-800nm。
本发明实施例中的复合隔音层对500Hz声源的吸收系数达到0.3以上，对1000Hz声源的吸收系数达到0.6以上，吸音性能较好；且通过消声层1和吸音层3的设置，声波进入到消声层1时，和无数的相互连通的孔洞壁摩擦，使声能转化为热能消化掉，从而起到消声作用，吸音层3的结构使得它与声波的接触面积增大，具有更好的吸音效果。
对于本领域技术人员而言，显然本发明不限于上述示范性实施例的细节，而且在不背离本发明的精神或基本特征的情况下，能够以其他的具体形式实现本发明。因此，无论从哪一点来看，均应将实施例看作是示范性的，而且是非限制性的，本发明的范围由所附权利要求而不是上述说明限定，因此旨在将落在权利要求的等同要件的含义和范围内的所有变化囊括在本发明内。不应将权利要求中的任何附图标记视为限制所涉及的权利要求。
此外，应当理解，虽然本说明书按照实施方式加以描述，但并非每个实施方式仅包含一个独立的技术方案，说明书的这种叙述方式仅仅是为清楚起见，本领域技术人员应当将说明书作为一个整体，各实施例中的技术方案也可以经适当组合，形成本领域技术人员可以理解的其他实施方式。
Claims (6)
1.一种纳米纤维复合隔音材料，其特征在于,包括消声层（1）、复合隔音层（2）和吸音层（3），其特征在于，消声层（1）、复合隔音层（2）和吸音层（3）复合叠加在一起，复合隔音层（2）位于中间；所述复合隔音层（2）由相互叠加在一起的第一单隔音层（21）和第二单隔音层（22）组成，所述第一单隔音层（21）和第二单隔音层（22）的结构相同，均包括复合纤维层（211）和纳米纤维层（212）。
2.根据权利要求1所述的一种纳米纤维复合隔音材料，其特征在于，所述消声层（1）和吸音层（3）均为三聚氰胺树脂泡沫材料制成的多孔结构。
3.根据权利要求1所述的一种纳米纤维复合隔音材料，其特征在于，所述消声层（1）背向复合隔音层（2）的一侧表面设置有第一面层（4）；所述吸音层（3）背向复合隔音层（2）的一侧表面设置有第二面层（5）。
4.根据权利要求3所述的一种纳米纤维复合隔音材料，其特征在于，所述第一面层（4）和第二面层（5）均采用复合聚乙烯热轧无纺布制成。
5.根据权利要求1所述的一种纳米纤维复合隔音材料，其特征在于，所述复合纤维层（211）的皮层材料为聚乳酸，芯层材料为聚己内酯，且为偏心结构，复合纤维层（211）采用双螺杆工艺制得，通过纺粘形成非织造布，厚度为3mm。
6.根据权利要求1所述的一种纳米纤维复合隔音材料，其特征在于，所述纳米纤维层（212）采用针头静电纺丝成型制得，以聚乳酸作为纳米纤维成纤原料，纳米纤维直径为200-800nm。
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201810720091.4A CN109049868A (zh) | 2018-07-03 | 2018-07-03 | 一种纳米纤维复合隔音材料 |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201810720091.4A CN109049868A (zh) | 2018-07-03 | 2018-07-03 | 一种纳米纤维复合隔音材料 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN109049868A true CN109049868A (zh) | 2018-12-21 |
Family
ID=64818545
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201810720091.4A Withdrawn CN109049868A (zh) | 2018-07-03 | 2018-07-03 | 一种纳米纤维复合隔音材料 |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN109049868A (zh) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110595052A (zh) * | 2019-09-20 | 2019-12-20 | 武汉源海博创科技有限公司 | 一种适应进风参数性能可调优的消声器 |
| CN112477316A (zh) * | 2020-11-25 | 2021-03-12 | 宜兴市泰宇汽车零部件有限公司 | 一种基于羽绒与纤维防脱落刚性骨架结构的超轻吸音材料 |
| CN112927668A (zh) * | 2019-12-05 | 2021-06-08 | 财团法人工业技术研究院 | 隔音构件 |
-
2018
- 2018-07-03 CN CN201810720091.4A patent/CN109049868A/zh not_active Withdrawn
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110595052A (zh) * | 2019-09-20 | 2019-12-20 | 武汉源海博创科技有限公司 | 一种适应进风参数性能可调优的消声器 |
| CN110595052B (zh) * | 2019-09-20 | 2022-03-18 | 宁波源海博创科技有限公司 | 一种适应进风参数性能可调优的消声器 |
| CN112927668A (zh) * | 2019-12-05 | 2021-06-08 | 财团法人工业技术研究院 | 隔音构件 |
| CN112477316A (zh) * | 2020-11-25 | 2021-03-12 | 宜兴市泰宇汽车零部件有限公司 | 一种基于羽绒与纤维防脱落刚性骨架结构的超轻吸音材料 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Cao et al. | Porous materials for sound absorption | |
| CN107675354B (zh) | 静电纺-熔喷-干法成网制备三组分吸音棉的方法及装置 | |
| CN107215046B (zh) | 一种三维卷曲皮芯复合纤维和纳米纤维复合隔音材料及其制备方法 | |
| Cao et al. | Hierarchically maze-like structured nanofiber aerogels for effective low-frequency sound absorption | |
| EP2467516B1 (en) | Apparatus, system, and method for forming nanofibers and nanofiber webs | |
| CN109049868A (zh) | 一种纳米纤维复合隔音材料 | |
| CN104918826B (zh) | 吸声性能优异的吸声材料及其制备方法 | |
| CN111376553B (zh) | 三明治结构互穿网络型弹性纤维吸音海绵及其制备方法 | |
| CN106149197B (zh) | 一种杂化结构可全生物降解复合隔音材料及其制备方法 | |
| CN103161032A (zh) | 一种无纺布及其制备方法和生产设备 | |
| CN107354587B (zh) | 一种空气过滤用二维网状极细纳米纤维材料及其制备方法 | |
| CN106048885B (zh) | 一种纤维素纤维和纳米纤维复合隔音材料及其制备方法 | |
| WO2014038722A1 (ja) | 不織布構造体およびその製造方法 | |
| JPH11152670A (ja) | カーペット材及びその製造方法 | |
| CN108859362A (zh) | 一种多层宽频吸声隔音材料及其制备方法 | |
| CN207207315U (zh) | 一种三维卷曲皮芯复合纤维和纳米纤维复合隔音材料 | |
| JP2016121426A (ja) | 吸音材 | |
| CN102174728B (zh) | 一种毛毡片材及其生产工艺 | |
| Liu et al. | A Fiber Sliding–Orientation Based Micromechanics Failure Model for Melt-Blown Nonwovens | |
| KR102612637B1 (ko) | 능동반응형 멀티스케일 흡음재 및 이의 제조방법 | |
| CN205272752U (zh) | 铝箔隔音棉 | |
| Ruello et al. | Excellent Wideband Acoustic Absorption of a Multifunctional Composite Fibrous Panel with a Dual-Pore Network from Milled Corrugated Box Wastes | |
| Rwawiire et al. | Empirical modeling of sound absorption properties of natural nonwoven fabric (Antiaris toxicaria Barkcloth) | |
| Zhu et al. | Recent advances on the fabrication and application of sound absorption coating-based textile composites | |
| Bai et al. | Flame-retardant, ultralight, and superelastic electrospun fiber sponges for effective sound absorption |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| WW01 | Invention patent application withdrawn after publication | ||
| WW01 | Invention patent application withdrawn after publication |
Application publication date: 20181221 |