Patent EP0245108A2 successfully refreshed from Google Patents.
EP0245108A2
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EP
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Process and apparatus for productionof a non-woven fiber sheet
Assignee: Toray Industries Inc
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Filing: 1987-05-08
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Granted: —
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Expires: 2007-05-08
Abstract
Abstract A process and apparatus for producing a non-woven, especially a non-woven electret, fiber sheet provides for directing the non-woven fibers at a collecting surface and into an electric field between at least one electrode and the collecting surface. This process, in which the fibers are collected in the electric field, enables economical production of a non-woven electret fiber sheet of a single layer structure having a large amount of polarized charges (giving a total electric charge per unit area of at least 7 x 10- 11 Coulomb/cm 2 ), and a weight per unit area of at least 60 g/m 2 , preferably greater than 80 g /m 2 . The non-woven electret sheet may have the large amount of electret charge throughout its thickness and/or a uniform weight distribution and thus have excellent dust collecting properties.
Inventors
- 👤 Ryoichi Togashi
- 👤 Katsutoshi Ando
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-28 21:39
CPC Classifications
D; D01; D01D; D01D10/00; B; B01; B01D; B01D39/00; B01D39/10; B01D39/14; B01D39/16; B01D39/1607; B01D39/1623; B03; B03C; B03C3/00; B03C3/28; B05; B05B; B05B5/00; B05B5/08; B05B5/087; D01D5/00; D01D5/08; D01D5/098; D01D5/0985; D04; D04H; D04H1/00; D04H1/40; D04H1/54; D04H1/56; D04H1/70; D04H1/72; D04H1/724; D04H3/00; D04H3/08; D04H3/16; H; H01; H01G; H01G7/00; H01G7/02; H01G7/021; H01G7/023; B01D2239/00; B01D2239/04; B01D2239/0435; B01D2239/0471; B01D2239/0478; B01D2239/06; B01D2239/0604; B01D2239/0622; B01D2239/065; B01D2239/10; B01D2239/12; B01D2239/1233; B01D2239/1291
Claims Analysis
Total Claims: 35
Claim 1
Independent Claim
45 words
An electret fiber sheet having a total electric charge per unit area, as measured using a thermally stimulated depolarization current apparatus, of at least 7 x 10-11 Coulomb/cm 2 , which sheet is a single layer structure having a weight of at least 60 g/m
Claim 2
Dependent Claim
45 words
An electret fiber sheet having a total electric charge per unit area, as measured using a thermally stimulated depolarization current apparatus, of at least 7 x 10-11 Coulomb/cm 2 , which sheet is a single layer structure having a weight of at least 60 g/m
Claim 3
Dependent Claim
20 words
An electret fiber sheet according to claim 1, having a weight per unit area greater than 80 g/m 2 .
Claim 4
Dependent Claim
21 words
An electret fiber sheet according to claim 2, having a weight per unit area of at least 100 g/m 2 .
Claim 5
Dependent Claim
33 words
An electret fiber sheet according to any preceding claim, having a weight variation, defined as a standard derivation, expressed as a percentage of average weight of the sheet, of not more than 8%.
Claim 6
Dependent Claim
27 words
An electret fiber sheet according to any preceding claim, having a total electric charge per unit area of at least 1 x 10 -10 Coulomb/cm 2 .
Claim 7
Dependent Claim
18 words
An electret fiber sheet according to any preceding claim, wherein the fiber sheet is a melt-blown fiber sheet.
Claim 8
Dependent Claim
28 words
An electret fiber sheet according to any preceding claim, wherein the electric charge is provided by polarized charges having an ordered orientation across the thickness of the sheet.
Claim 9
Dependent Claim
19 words
An electret fiber sheet according to any preceding claim, wherein the peak temperature of depolarization is at least 50°C.
Claim 10
Dependent Claim
18 words
An electret fiber sheet according to claim 8, wherein the peak temperature of depolarization is at least 80°C.
Claim 11
Dependent Claim
26 words
An electret fiber sheet according to any preceding claim, wherein the fibers are of a material having a volume resistivity of at least 10 -10 Ω.cm.
Claim 12
Dependent Claim
21 words
An electret fiber sheet according to any preceding claim, wherein the fibers have an average diameter of not more than 5pm.
Claim 13
Dependent Claim
46 words
A process for producing a non-woven fiber sheet in which the fibers are passed through an electric field and directed at a collecting surface, characterized in that the fibers are collected in a said electric field formed between at least one electrode and the collecting surface.
Claim 14
Dependent Claim
46 words
A process for producing a non-woven fiber sheet in which the fibers are passed through an electric field and directed at a collecting surface, characterized in that the fibers are collected in a said electric field formed between at least one electrode and the collecting surface.
Claim 15
Dependent Claim
21 words
A process according to claim 12, wherein the said non-woven fiber sheet has electret properties provided by the said electric field.
Claim 16
Dependent Claim
29 words
A process according to claim 12 or 13, wherein the material of the fibers is an organic polymer having a volume resistivity of not less than 10 10 Ω.cm.
Claim 17
Dependent Claim
16 words
A process according to claim 12, 13 or 14, which includes continuously rotating the collecting surface.
Claim 18
Dependent Claim
17 words
A process according to any one of claims 12 to 15, wherein the collecting surface is metallic.
Claim 19
Dependent Claim
49 words
A process according to any one of claims 12 to 15, wherein the collecting surface is provided by a metallic surface covered with a material having a volume resistivity which is either (a) from 10 -3 to 10 9 Ω.cm inclusive, or (b) not less than 10 12 Ω.cm.
Claim 20
Dependent Claim
38 words
A process according to any one of claims 12 to 17, wherein the electric field is formed between the electrode and the collecting surface by applying a high DC voltage to the electrode and grounding the collecting surface.
Claim 21
Dependent Claim
55 words
A process according to any one of claims 12 to 17, wherein the electric field is formed between the electrode and the collecting surface by applying to the electrode a high DC voltage of one polarity and to the collecting surface a high DC voltage of a polarity opposite to that applied to the electrode.
Claim 22
Dependent Claim
25 words
A process according to any one of claims 12 to 19, wherein the electric field has a field strength of not less than 1 kV/cm.
Claim 23
Dependent Claim
25 words
A process according to any one of claims 12 to 20, which additionally includes forming the fibers to be collected by a melt-blow spinning process.
Claim 24
Dependent Claim
31 words
A process according to any one of claims 13 to 21, wherein the resultant electret fiber sheet has a total electric charge per unit area of at least Ix 10-10 Coulomb/cm2.
Claim 25
Dependent Claim
46 words
A fiber sheet produced by a process according to any one of claims 12 to 22, having a weight per unit area variation, defined as a standard deviation, expressed as a percentage of average weight per unit area of the sheet, of not more than 8%.
Claim 26
Dependent Claim
24 words
A fiber sheet according to claim 23, having a particle collecting efficiency of at least 65% after removal therefrom of any electric charge present.
Claim 27
Dependent Claim
16 words
A fiber sheet according to claim 24, having a particle collecting efficiency of at least 95%.
Claim 28
Independent Claim
73 words
An apparatus for producing a non-woven fiber sheet, which apparatus comprises a collector for providing a fiber collecting surface, means for directing fibers at the collecting surface and at least one electrode, characterized in that the or each electrode is arranged, relative to the collecting surface, so as to be capable of providing an electric field between the or each electrode and the collector, whereby the fibers are collected in the electric field.
Claim 29
Independent Claim
73 words
An apparatus for producing a non-woven fiber sheet, which apparatus comprises a collector for providing a fiber collecting surface, means for directing fibers at the collecting surface and at least one electrode, characterized in that the or each electrode is arranged, relative to the collecting surface, so as to be capable of providing an electric field between the or each electrode and the collector, whereby the fibers are collected in the electric field.
Claim 30
Dependent Claim
12 words
An apparatus according to claim 26, wherein the collector is continuously rotatable.
Claim 31
Dependent Claim
14 words
An apparatus according to claim 26, wherein the collector provides a metallic collecting surface.
Claim 32
Dependent Claim
53 words
An apparatus according to claim 26, 27 or 28, wherein the collector comprises an element providing a metallic surface and a cover, covering the metallic surface, of a material having a volume resistivity which is either (a) from 10 -3 to 10 9 Ω.cm. inclusive or (b) not less than 10 12 Ω.cm.
Claim 33
Independent Claim
23 words
An apparatus according to any one of claims 26 to 29 having a plurality of electrodes, each of which is a needle electrode.
Claim 34
Independent Claim
19 words
An apparatus according to any one of claims 26 to 30, which includes suction apparatus disposed behind the collector.
Claim 35
Independent Claim
17 words
An apparatus according to any one of claims 26 to 31, which additionally includes melt-blow spinning apparatus.
References Cited (Backward Citations)
No citation records indexed.
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