US6267252B1
Expired / Lapsed
US
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Fine particle filtration medium including an airlaid composite
Assignee: Kimberly Clark Worldwide Inc
•
Filing: 1999-12-08
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Granted: 2001-07-31
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Expires: 2019-12-08
Abstract
Abstract The present invention pertains to a filter medium including an airlaid composite, which is made of pulp fibers, at least about 2% by weight bicomponent fiber, and moisture. This airlaid composite is unique in that, when used as a filter medium, it exhibits advantageous filtering properties as well as physical strength. The bicomponent fibers of the present invention include a first polymer component and a second polymer component, and the first polymer component melts at a temperature lower than the melting temperature of the second polymer component. Mixing of the pulp fibers with the bicomponent fibers is done in such a way that the fibers are evenly dispersed in the airlaid composite. This airlaid composite is then heated such that at least a portion of the first polymer component of the bicomponent fiber is melted, which bond the bicomponent fibers to many of the pulp and other bicomponent fibers when cooled. Moisture is added to the composite to further facilitate bonding when the composite is subsequently subjected to calendering. Optionally, a support structure may be used to supplement the strength of the airlaid composite. The filter medium of the present invention is characterized by a drape stiffness of at least about 6 cm, and tensile strength of at least about 4 kg. It may also exhibit relatively low average pore size and bubble point.
Inventors
- 👤 Nicole Michele Amsler
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 04:39
CPC Classifications
B; B01; B01D; B01D39/00; B01D39/14; B01D39/16; B01D39/18; B01D39/1607; B01D39/1623; B01D39/163; Y; Y10; Y10T; Y10T428/00; Y10T428/249921; Y10T428/249924; Y10T428/249933; Y10T428/249938; Y10T428/24994
Claims Analysis
Total Claims: 31
Claim 1
Independent Claim
127 words
A filtration medium comprising: a thin, calendered airlaid composite further comprising: a) pulp fibers; b) at least about 11% by weight bicomponent fiber comprising a first polymer component and a second polymer component, wherein said first polymer component melts at a temperature lower than the melting temperature of said second polymer component, and further wherein said bicomponent fibers are integrally mixed and evenly dispersed with said pulp fibers and said first polymer component is bonded to many of said pulp fibers and bicomponent fibers; and c) moisture; wherein percent by weight is based on the total weight of a) and b), and further wherein said airlaid composite has a drape stiffness of at least about 6 cm, and a tensile strength of at least about 4 kg.
Claim 2
Dependent Claim
127 words
A filtration medium comprising: a thin, calendered airlaid composite further comprising: a) pulp fibers; b) at least about 11% by weight bicomponent fiber comprising a first polymer component and a second polymer component, wherein said first polymer component melts at a temperature lower than the melting temperature of said second polymer component, and further wherein said bicomponent fibers are integrally mixed and evenly dispersed with said pulp fibers and said first polymer component is bonded to many of said pulp fibers and bicomponent fibers; and c) moisture; wherein percent by weight is based on the total weight of a) and b), and further wherein said airlaid composite has a drape stiffness of at least about 6 cm, and a tensile strength of at least about 4 kg.
Claim 3
Dependent Claim
20 words
The filtration medium of claim 1 wherein the medium is effective as a filtering device for gas and liquid fluids.
Claim 4
Dependent Claim
17 words
The filtration medium of claim 2 wherein the medium is effective as a filtering device for liquids.
Claim 5
Dependent Claim
17 words
The filtration medium of claim 1 wherein said airlaid composite comprises about 11-30% by weight bicomponent fiber.
Claim 6
Dependent Claim
17 words
The filtration medium of claim 1 wherein said airlaid composite comprises about 20-30% by weight bicomponent fiber.
Claim 7
Dependent Claim
18 words
The filtration medium of claim 1 wherein said medium is corrugated to maximize surface area and filtration efficiency.
Claim 8
Dependent Claim
20 words
The filtration medium of claim 1 wherein said medium has an average pore size of less than about 100 microns.
Claim 9
Dependent Claim
20 words
The filtration medium of claim 4 wherein said medium has an average pore size of less than about 25 microns.
Claim 10
Dependent Claim
21 words
The filtration medium of claim 1 wherein said medium has an average pore size of about 5 to about 10 microns.
Claim 11
Dependent Claim
22 words
The filtration medium of claim 1 wherein said medium is effective for filtering fine particles having a size of about 0-10 microns.
Claim 12
Dependent Claim
133 words
A filtration medium comprising: a) a thin, calendered airlaid composite further comprising: i) pulp fibers; ii) at least about 2% by weight bicomponent fiber comprising a first polymer component and a second polymer component, wherein said first polymer component melts at a temperature lower than the melting temperature of said second polymer component, and further wherein said bicomponent fibers are integrally mixed and evenly dispersed with said pulp fibers and said first polymer component is bonded to many of said pulp fibers and bicomponent fibers; wherein percent by weight is based on the total weight of i) and ii), and further wherein said airlaid composite has a drape stiffness of at least about 6 cm, and a dry tensile strength of at least about 4 kg; iii) moisture; and b) a support structure.
Claim 13
Dependent Claim
133 words
A filtration medium comprising: a) a thin, calendered airlaid composite further comprising: i) pulp fibers; ii) at least about 2% by weight bicomponent fiber comprising a first polymer component and a second polymer component, wherein said first polymer component melts at a temperature lower than the melting temperature of said second polymer component, and further wherein said bicomponent fibers are integrally mixed and evenly dispersed with said pulp fibers and said first polymer component is bonded to many of said pulp fibers and bicomponent fibers; wherein percent by weight is based on the total weight of i) and ii), and further wherein said airlaid composite has a drape stiffness of at least about 6 cm, and a dry tensile strength of at least about 4 kg; iii) moisture; and b) a support structure.
Claim 14
Dependent Claim
19 words
The filtration medium of claim 11 wherein said airlaid composite comprises at least about 2-30% by weight bicomponent fiber.
Claim 15
Dependent Claim
16 words
The filtration medium of claim 12 wherein said support structure comprises a matrix of fibrous material.
Claim 16
Dependent Claim
19 words
The filtration medium of claim 13 wherein said matrix of fibrous material comprises woven, scrim, knit or nonwoven fabrics.
Claim 17
Dependent Claim
14 words
The filtration medium of claim 12 wherein said support structure comprises a frame-like structure.
Claim 18
Dependent Claim
15 words
The filtration medium of claim 14 wherein said support structure further comprises a frame-like structure.
Claim 19
Dependent Claim
11 words
The filtration medium of claim 12 wherein said medium is corrugated.
Claim 20
Dependent Claim
20 words
The filtration medium of claim 12 wherein said medium has an average pore size of less than about 100 microns.
Claim 21
Dependent Claim
20 words
The filtration medium of claim 12 wherein said medium has an average pore size of less than about 25 microns.
Claim 22
Dependent Claim
21 words
The filtration medium of claim 12 wherein said medium has an average pore size of about 5 to about 10 microns.
Claim 23
Dependent Claim
22 words
The filtration medium of claim 12 wherein said medium is effective for filtering fine particles having a size of about 0-10 microns.
Claim 24
Dependent Claim
142 words
A filtration medium comprising: a) a thin, calendered airlaid composite further comprising: i) pulp fibers; ii) at least about 2% by weight bicomponent fiber comprising a first polymer component and a second polymer component, wherein said first polymer component melts at a temperature lower than the melting temperature of said second polymer component, and further wherein said bicomponent fibers are integrally mixed and evenly dispersed with said pulp fibers and said first polymer component is bonded to many of said pulp fibers and bicomponent fibers; iii) moisture; and b) a support structure; wherein percent by weight is based on the total weight of i) and ii), and further wherein said airlaid composite has a drape stiffness of at least about 6 cm, a bubble point of less than about 27 microns, and a dry tensile strength of at least about 4 kg.
Claim 25
Dependent Claim
142 words
A filtration medium comprising: a) a thin, calendered airlaid composite further comprising: i) pulp fibers; ii) at least about 2% by weight bicomponent fiber comprising a first polymer component and a second polymer component, wherein said first polymer component melts at a temperature lower than the melting temperature of said second polymer component, and further wherein said bicomponent fibers are integrally mixed and evenly dispersed with said pulp fibers and said first polymer component is bonded to many of said pulp fibers and bicomponent fibers; iii) moisture; and b) a support structure; wherein percent by weight is based on the total weight of i) and ii), and further wherein said airlaid composite has a drape stiffness of at least about 6 cm, a bubble point of less than about 27 microns, and a dry tensile strength of at least about 4 kg.
Claim 26
Dependent Claim
17 words
The filtration medium of claim 22 wherein said airlaid composite comprises about 2-30% by weight bicomponent fiber.
Claim 27
Dependent Claim
16 words
The filtration medium of claim 22 wherein said support structure is a matrix of fibrous material.
Claim 28
Dependent Claim
19 words
The filtration medium of claim 24 wherein said matrix of fibrous material comprises woven, scrim, knit or nonwoven fabrics.
Claim 29
Dependent Claim
14 words
The filtration medium of claim 23 wherein said support structure comprises a frame-like structure.
Claim 30
Dependent Claim
21 words
The filtration medium of claim 23 wherein said airlaid composite has a bubble point of less than or equal to 22.
Claim 31
Dependent Claim
22 words
The filtration medium of claim 22 wherein said medium is effective for filtering fine particles having a size of about 0-10 microns.
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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) | 2004-07-30 | 2005-01-29 | 2005-07-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2008-07-30 | 2009-01-29 | 2009-07-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2012-07-30 | 2013-01-29 | 2013-07-31 | $7700.00 | Window Closed / Lapsed |