Patent US4469746A successfully refreshed from Google Patents.
US4469746A
Expired / Lapsed
US
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Silica coated absorbent fibers
Assignee: Procter and Gamble Co
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Filing: 1982-06-01
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Granted: 1984-09-04
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Expires: 2002-06-01
Abstract
Abstract Fibrous webs comprising fibers coated with a continuous film comprising silica have excellent absorbent and wicking properties. The fibers themselves may be hydrophilic (e.g., cellulose) or hydrophobic (e.g., a polyolefin or a polyester).
Inventors
- 👤 Paul T. Weisman
- 👤 Herbert L. Retzsch
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 21:33
CPC Classifications
A; A61; A61L; A61L15/00; A61L15/16; A61L15/18; Y; Y10; Y10S; Y10S428/00; Y10S428/913; Y10T; Y10T428/00; Y10T428/29; Y10T428/2913; Y10T428/2933; Y10T428/31504; Y10T428/31652; Y10T428/31667; Y10T442/00; Y10T442/20; Y10T442/2484
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
27 words
A hydrophilic absorbent fibrous web comprising thermoplastic polymer fibers which are coated with a continuous film consisting essentially of positively charged silica and a crosslinkable cationic polyelectrolyte.
Claim 2
Dependent Claim
27 words
A hydrophilic absorbent fibrous web comprising thermoplastic polymer fibers which are coated with a continuous film consisting essentially of positively charged silica and a crosslinkable cationic polyelectrolyte.
Claim 3
Dependent Claim
110 words
A process for coating thermoplastic fibers with a continuous film comprising silica, said process comprising the step of immersing the fibers in a positively charged silica aquasol containing colloidal silica with average particle size in the range of from about 3 nm to about 150 nm, said aquasol having a pH of from about 1 to about 5 and an ionic strength of from about 0.003 to about 0.45, followed by the step of immersing the fibers in an aqueous solution of a water-soluble, cationic, crosslinkable polyelectrolyte, said solution having a pH of from about 1 to about 7 and an ionic strength of from about 0.003 to about 0.45.
Claim 4
Dependent Claim
110 words
A process for coating thermoplastic fibers with a continuous film comprising silica, said process comprising the step of immersing the fibers in a positively charged silica aquasol containing colloidal silica with average particle size in the range of from about 3 nm to about 150 nm, said aquasol having a pH of from about 1 to about 5 and an ionic strength of from about 0.003 to about 0.45, followed by the step of immersing the fibers in an aqueous solution of a water-soluble, cationic, crosslinkable polyelectrolyte, said solution having a pH of from about 1 to about 7 and an ionic strength of from about 0.003 to about 0.45.
Claim 5
Dependent Claim
23 words
The absorbent fibrous web of claim 1 wherein the crosslinkable cationic polyelectrolyte is a melamine-formaldehyde resin, a urea-formaldehyde resin or a polyvinylamide resin.
Claim 6
Dependent Claim
26 words
The process of claim 2 wherein the colloidal silica has an average particle size in the range of from about 3 nm to about 50 nm.
Claim 7
Dependent Claim
21 words
The process of claim 2 wherein the absolute air pressure over the silica aquasol is reduced to below 10 cm Hg.
Claim 8
Dependent Claim
23 words
The process of claim 2 wherein the concentration of the aqueous solution of the cationic polyelectrolyte is from about 0.5% to about 6%.
Claim 9
Dependent Claim
19 words
The process of claim 2 wherein the pH of the polyelectrolyte solution is from about 4 to about 6.
Claim 10
Dependent Claim
20 words
The process of claim 2 wherein the ionic strength of the polyelectrolyte solution is from about 0.015 to about 0.060.
Claim 11
Dependent Claim
20 words
The process of claim 2 wherein the cationic polyelectrolyte is a melamine-formaldehyde resin, a urea-formaldehyde resin or a polyvinylamide resin.
Claim 12
Dependent Claim
69 words
A process for coating hydrophilic fibers with a continuous film comprising silica, said process comprising the step of immersing the fibers in a silica aquasol containing from about 0.01% to about 2% positively charged colloidal silica, said aquasol having a pH of from about 2 to about 9, and the amount of aquasol being such as to result in a silica:fiber ratio of from about 1:40 to about 1:20.
Claim 13
Dependent Claim
69 words
A process for coating hydrophilic fibers with a continuous film comprising silica, said process comprising the step of immersing the fibers in a silica aquasol containing from about 0.01% to about 2% positively charged colloidal silica, said aquasol having a pH of from about 2 to about 9, and the amount of aquasol being such as to result in a silica:fiber ratio of from about 1:40 to about 1:20.
Claim 14
Dependent Claim
13 words
A process according to claim 10 wherein the hydrophilic fibers are cellulose fibers.
Claim 15
Dependent Claim
20 words
A process according to claim 10 wherein the silica aquasol has a pH of from about 6 to about 8.
Claim 16
Dependent Claim
36 words
A process according to claim 10 wherein the fibers are immersed in a silica aquasol at a pH of about 3 and the pH is subsequently raised to about 8 in the presence of the fibers.
Claim 17
Dependent Claim
8 words
The product of the process of claim 2.
Claim 18
Dependent Claim
8 words
The product of the process of claim 10.
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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) | 1987-09-04 | 1988-03-05 | 1988-09-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-09-04 | 1992-03-05 | 1992-09-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-09-04 | 1996-03-05 | 1996-09-04 | $7700.00 | Window Closed / Lapsed |