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US5454946A
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Filter material for filtering leucocytes from blood
Assignee: Charter Medical Ltd
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Filing: 1994-02-22
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Granted: 1995-10-03
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Expires: 2014-02-22
Abstract
Abstract A filter material for filtering leucocytes from a fraction of or whole human blood, comprises a web having a thickness of at least about 1 millimeter and a bulk density of about 0.05 to 0.4 g/cm 3 . The web has a plurality of interlocked matrix fibers distributed in the web to form a matrix thereof with spaces between adjacent interstices of interlocked fibers. The matrix fibers are composed mainly of about 1 to 3 micron diameter glass fibers, i.e. at least 75% of the weight of the web being the glass fibers. A plurality of fibrillated particles of textile fiber material, having a surface area of between 5 and 100 square meters per gram are disposed within the spaces of the matrix. The weight ratio of the fibrillated particles to the matrix fibers is between about 1:99 and 40:60. A thermoplastic binder is disposed at least at cross-over portions of the matrix fibers, with the amount of the binder being about 0.1% to 10% by weight of the web.
Inventors
- 👤 David G. Heagle
- 👤 John J. Hiers
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 04:52
CPC Classifications
B; B01; B01D; B01D39/00; B01D39/08; B01D39/083; B01D39/14; B01D39/16; B01D39/1607; B01D39/1623; B01D39/163; D; D04; D04H; D04H1/00; D04H1/40; D04H1/54; D04H1/58; D04H1/587; D04H1/64; A; A61; A61M; A61M2202/00; A61M2202/04; A61M2202/0413; A61M2202/0439; B01D2239/00; B01D2239/02; B01D2239/0216; B01D2239/0225; B01D2239/04; B01D2239/0407; B01D2239/06; B01D2239/065; B01D2239/0654; B01D2239/08; B01D2239/086; B01D2239/12; B01D2239/1225; B01D2239/1233; B01D2239/1291; Y; Y10; Y10T; Y10T428/00; Y10T428/25; Y10T428/254; Y10T442/00; Y10T442/60; Y10T442/699
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
177 words
A filter material for filtering leucocytes from a fraction of or whole blood, comprising: a shape-sustaining laid web having a thickness of at least about 1 millimeter and a bulk density of between about 0.05 and 0.4 g/cm 3 said web having: (i) a plurality of interlocked, matrix fibers substantially uniformly distributed in said web so as to form a matrix of the fibers with spaces between adjacent interstices of interlocked fibers and the matrix fibers containing at least 75% by weight of the web of glass matrix fibers having an average diameter of between about 1.0 and about 3 microns; (ii) a plurality of fibrillated particles of polymeric material having fibrils and a surface area of at least about 5 square meters per gram substantially disposed within said spaces and the weight ratio of the fibrillated particles to matrix fibers is between about 1:99 and 40:60; and (iii) a thermoplastic binder disposed at least at cross-over positions of said matrix fibers, the amount of the binder being about 0.1% to 10% by weight of the web.
Claim 2
Dependent Claim
177 words
A filter material for filtering leucocytes from a fraction of or whole blood, comprising: a shape-sustaining laid web having a thickness of at least about 1 millimeter and a bulk density of between about 0.05 and 0.4 g/cm 3 said web having: (i) a plurality of interlocked, matrix fibers substantially uniformly distributed in said web so as to form a matrix of the fibers with spaces between adjacent interstices of interlocked fibers and the matrix fibers containing at least 75% by weight of the web of glass matrix fibers having an average diameter of between about 1.0 and about 3 microns; (ii) a plurality of fibrillated particles of polymeric material having fibrils and a surface area of at least about 5 square meters per gram substantially disposed within said spaces and the weight ratio of the fibrillated particles to matrix fibers is between about 1:99 and 40:60; and (iii) a thermoplastic binder disposed at least at cross-over positions of said matrix fibers, the amount of the binder being about 0.1% to 10% by weight of the web.
Claim 3
Dependent Claim
22 words
The filter material of claim 1 wherein said diameter of the glass matrix fibers is between about 1.0 and about 2.5 microns.
Claim 4
Dependent Claim
18 words
The filter material of claim 2 wherein said diameter of the glass matrix fibers is about 1.8 microns.
Claim 5
Dependent Claim
21 words
The filter material of claim 1 wherein the average length of the glass fibers is between about 0.3 to 6.0 millimeters.
Claim 6
Dependent Claim
23 words
The filter material of claim 4 wherein the matrix fibers contain at least 85% by weight of the web of glass matrix fibers.
Claim 7
Dependent Claim
18 words
The filter material of claim 1 wherein the binder has a softening temperature of below about 400° F.
Claim 8
Dependent Claim
20 words
The filter material of claim 6 wherein the binder is emulsifiable and is applied to the web as an emulsion.
Claim 9
Dependent Claim
17 words
The filter material of claim 1 wherein the add-ons of binder solids is about 1% to 10%.
Claim 10
Dependent Claim
17 words
The filter material of claim 8 wherein the add-ons of binder solids is about 5% to 10%.
Claim 11
Dependent Claim
23 words
The filter material of claim 1 wherein the binder is flexible at room temperature and has a glass transition temperature above 100° F.
Claim 12
Dependent Claim
18 words
The filter material of claim 1 wherein the binder is selected from polyacrylics and acrylates and mixtures thereof.
Claim 13
Dependent Claim
53 words
The filter material of claim 1 wherein the matrix fibers are so interlocked together and the fibrillated particles are so interlocked to the matrix fibers that said filter material can withstand a filtering blood pressure drop of at least 2 feet of head without substantial displacement of the fibrillated particles from the web.
Claim 14
Dependent Claim
68 words
The filter material of claim 1 wherein at least a portion of the matrix fibers are sheath/core fibers having a sheath of low melt temperature polymer and a core of higher melt temperature polymer and the web has experienced a temperature sufficient to at least soften said low melt polymer and cause at least some adherence of the matrix fibers and to the fibrils of the fibrillated particles.
Claim 15
Dependent Claim
23 words
The filter material of claim 13 wherein from about 1% to about 20% of the weight of the web is the sheath/core fibers.
Claim 16
Dependent Claim
51 words
The filter material of claim 14 wherein from about 5% to about 20% of the weight of the web is the sheath/core fibers and the filter material can withstand a filtering blood pressure drop of at least 5 feet of head without substantial displacement of the fibrillated particles from the web.
Claim 17
Dependent Claim
39 words
The filter material of claim 1 wherein the fibrillated particles are particles of a textile fiber material selected from the group consisting of polyester fiber material, acrylic textile material, nylon fiber material, polyolefin fiber material and cellulosic fiber material.
Claim 18
Dependent Claim
20 words
The filter material of claim 16 wherein the textile fiber material of the fibrillated particles is predominantly cellulosic fiber material.
Claim 19
Dependent Claim
14 words
The filter material of claim 17 wherein the cellulosic fiber material is cellulose acetate.
Claim 20
Dependent Claim
26 words
The filter material of claim 1 wherein the fibrillated particles have lengths of less than about 1000 microns and widths of about 0.1 to 50 microns.
Claim 21
Dependent Claim
46 words
The filter material of claim 1 wherein said surface area of the fibrillated particles is at least 10 square meters per gram and up to 100 square meters per gram and the surface area of the filter material is at least 1.5 square meters per gram.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1998-10-02 | 1999-04-03 | 1999-10-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2002-10-02 | 2003-04-03 | 2003-10-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2006-10-02 | 2007-04-03 | 2007-10-03 | $7700.00 | Window Closed / Lapsed |