Patent US3765690A successfully refreshed from Google Patents.
US4469746A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Silica coated absorbent fibers
Assignee: Procter and Gamble Co
•
Filing: 1982-06-01
•
Granted: 1984-09-04
•
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 17:49
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.
References Cited (Backward Citations)
US2443512A
Cited
US2658835A
Cited
US3381688A
Cited
US3720539A
Cited
US3775141A
Cited
US4049764A
Cited
US4307143A
Cited
US4311553A
Cited
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 |