US4363682A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for the superficial treatment of a fibrous filtering layer, which is non-woven and highly aerated, forming electret
Assignee: Seplast
•
Filing: 1981-04-06
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Granted: 1982-12-14
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Expires: 2001-04-06
Abstract
Abstract The process of the invention consists in smoothing the or each fluffy surface of the layer by exerting a slight friction under low pressure so that the projecting fibers are flattened on the subjacent fibrous mass without the latter being compressed, the friction being exerted at a softening temperature such that the superficial fibers are welded together to form a skin or porous glaze. The smoothing is preferably effected by means of a metal mass whose temperature is between 115° and 150° C. This process may be applied to the outer face of a filtering breathing mask constituted by an envelope made of this fibrous material covering a relatively rigid porous shell for protection of the skin; it may also be applied to at least one of the faces of filtering layers equipping filters of any type.
Inventors
- 👤 Bernard Thiebault
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 17:06
CPC Classifications
D; D04; D04H; D04H1/00; D04H1/40; D04H1/54; D04H1/542; D04H1/544; A; A41; A41D; A41D13/00; A41D13/05; A41D13/11; A41D13/1107; A41D13/1138; A41D13/1146; B; B01; B01D; B01D39/00; B01D39/14; B01D39/16; B01D39/1607; B01D39/1623; B03; B03C; B03C3/00; B03C3/28; B01D2239/00; B01D2239/04; B01D2239/0435; B01D2239/0471; B01D2239/0478; B01D2239/06; B01D2239/065; B01D2239/0672; B01D2239/08; B01D2239/086; Y; Y10; Y10T; Y10T156/00; Y10T156/17; Y10T156/1702; Y10T156/1712; Y10T156/1741; Y10T428/00; Y10T428/24; Y10T428/24942; Y10T428/24992; Y10T442/00; Y10T442/60; Y10T442/69
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
104 words
A process for superficially treating a highly aerated, fluffy, fibrous electret, air filtering fabric layer having fibers projecting above a subjacent mass, which comprises smoothing at least one fluffy surface of the layer by exerting a light friction under low pressure to flatten the projected fibers on the subjacent fiber mass without substantial compression of said mass, and at a softening temperature to weld the superficial fibers together and to form a skin or pourous glaze which will be unclogged and by a surface effect adds to the filtering power of the electrostatic filtering layer without reducing the gaseous flow passing through the layer.
Claim 2
Dependent Claim
104 words
A process for superficially treating a highly aerated, fluffy, fibrous electret, air filtering fabric layer having fibers projecting above a subjacent mass, which comprises smoothing at least one fluffy surface of the layer by exerting a light friction under low pressure to flatten the projected fibers on the subjacent fiber mass without substantial compression of said mass, and at a softening temperature to weld the superficial fibers together and to form a skin or pourous glaze which will be unclogged and by a surface effect adds to the filtering power of the electrostatic filtering layer without reducing the gaseous flow passing through the layer.
Claim 3
Dependent Claim
25 words
The process of claim 1 wherein the smoothing is effected by means of a metal mass having a temperature is between 115° and 150° C.
Claim 4
Dependent Claim
61 words
The process of claim 1 wherein the fluffy filtering layer is advanced passed heating and friction means, the relative speed and the pressure applied therebetween and the duration of contact are determined as a function of the heat supplied to produce a partial self-adhesive fusion of the surface fibres while avoiding the propagation of this effect in the subjacent fibrous mass.
Claim 5
Dependent Claim
23 words
The process of claim 2, wherein the heating means is a heating mirror and the filtering layer advances abutting on the heating mirror.
Claim 6
Dependent Claim
58 words
The process of claim 2 wherein the filtering layer is driven by calender passes through a smoothing device comprising a subjacent fixed or rotary support and a heating cylinder producing a speed of tangential flattening of the projecting fibers of the layer, which speed is different from the speed of advance of said layer produced by the calender.
Claim 7
Dependent Claim
16 words
The process of claims 1, 2, 3, 4 or 5, wherein the filtering layer comprises polypropylene.
References Cited (Backward Citations)
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DE2249138A1
Cited
US3936337A
Cited
US4093763A
Cited
US4178157A
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1985-12-13 | 1986-06-14 | 1986-12-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-12-13 | 1990-06-14 | 1990-12-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-12-13 | 1994-06-14 | 1994-12-14 | $7700.00 | Window Closed / Lapsed |