US4474949A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Freeze dried microfibrilar cellulose
Assignee: Personal Products Co
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Filing: 1983-05-06
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Granted: 1984-10-02
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Expires: 2003-05-06
Abstract
Abstract Absorbent retentive pulp, produced by mechanically treating a dispersion of cellulose fiber to the disintegrated and outer secondary walls to microfibrillar form. The beaten dispersion is then freeze dried.
Inventors
- 👤 Pronoy K. Chatterjee
- 👤 Kambiz B. Makoui
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 07:58
CPC Classifications
C; C08; C08L; C08L1/00; C08L1/02; A; A61; A61L; A61L15/00; A61L15/16; A61L15/22; A61L15/28; Y; Y10; Y10S; Y10S241/00; Y10S241/37; Y10S604/00; Y10S604/904
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
41 words
An absorbent product comprising as an absorbent element therein fibrous cellulose pulp having been beaten and freeze dried, said beaten, freeze dried cellulose pulp comprising sheet like particles of microfibrils, said sheet like particles arranged as discontinuous walls surrounding void volumes.
Claim 2
Dependent Claim
41 words
An absorbent product comprising as an absorbent element therein fibrous cellulose pulp having been beaten and freeze dried, said beaten, freeze dried cellulose pulp comprising sheet like particles of microfibrils, said sheet like particles arranged as discontinuous walls surrounding void volumes.
Claim 3
Dependent Claim
32 words
The absorbent product of claim 1 wherein said beaten, freeze dried cellulose pulp has a Porous Plate Capacity of at least 15 g/g with a testing fluid of 1% NaCl aqueous solution.
Claim 4
Dependent Claim
41 words
The absorbent product of claim 1 wherein said beaten, freeze dried cellulose pulp has a Porous Plate Retention of at least 10 g/g with a testing fluid of 1% NaCl aqueous solution under a hydraulic head of 35.5 cm of liquid.
Claim 5
Dependent Claim
37 words
The absorbent product of claim 1 wherein said beaten, freeze dried cellulose pulp comprises said sheets having a largest dimension of from about 2 microns to about 130 microns and a thickness of less than five microns.
Claim 6
Dependent Claim
13 words
The absorbent product of claim 1 wherein said product is a sanitary napkin.
Claim 7
Dependent Claim
13 words
The absorbent product of claim 1 wherein said product is a catamenial tampon.
Claim 8
Dependent Claim
13 words
The absorbent product of claim 1 wherein said product is a disposable diaper.
Claim 9
Dependent Claim
13 words
The absorbent product of claim 1 wherein said product is a wound dressing.
Claim 10
Dependent Claim
13 words
The product of claim 1 wherein the starting cellulose fibers are wood pulp.
Claim 11
Dependent Claim
70 words
An absorbent product comprising as an absorbent element therein highly absorbent, retentive cellulose pulp, said cellulose pulp having been provided by: forming a dilute aqueous dispersion of cellulose fibers; extensively beating said slurry to a degree such that at least the outermost of the secondary walls of said cellulose fibers are essentially completely disintegrated into microfibrillar form; and freeze drying said slurry; whereby said highly absorbent, retentive cellulose pulp results.
Claim 12
Dependent Claim
70 words
An absorbent product comprising as an absorbent element therein highly absorbent, retentive cellulose pulp, said cellulose pulp having been provided by: forming a dilute aqueous dispersion of cellulose fibers; extensively beating said slurry to a degree such that at least the outermost of the secondary walls of said cellulose fibers are essentially completely disintegrated into microfibrillar form; and freeze drying said slurry; whereby said highly absorbent, retentive cellulose pulp results.
Claim 13
Dependent Claim
23 words
The product of claim 10 wherein said aqueous dispersion has a solid content ranging from about 0.5 to about 10.0% solids, by weight.
Claim 14
Dependent Claim
23 words
The product of claim 11 wherein said aqueous dispersion has a solid content ranging from about 1.5 to about 6.0% solids, by weight.
Claim 15
Dependent Claim
28 words
The product of claim 10 wherein beating is carried out to an extent to reduce said cellulose fibers to a Canadian Standard Freeness value of less than 100.
Claim 16
Dependent Claim
28 words
The product of claim 13 wherein beating is carried out to an extent to reduce said cellulose fibers to a Canadian Standard Freeness value of less than 50.
Claim 17
Dependent Claim
12 words
The product of claim 10 wherein said product is a sanitary napkin.
Claim 18
Dependent Claim
12 words
The product of claim 10 wherein said product is a catamenial tampon.
Claim 19
Dependent Claim
12 words
The product of claim 10 wherein said product is a disposable diaper.
Claim 20
Dependent Claim
12 words
The product of claim 10 wherein said product is a wound dressing.
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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) | 1987-10-02 | 1988-04-02 | 1988-10-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-10-02 | 1992-04-02 | 1992-10-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-10-02 | 1996-04-02 | 1996-10-02 | $7700.00 | Window Closed / Lapsed |