US3989416A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Dense paper and method of manufacturing
Assignee: Individual
•
Filing: 1975-04-03
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Granted: 1976-11-02
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Expires: 1995-04-03
Abstract
Abstract A dense paper comprising a web of cellulosic fibers and an impregnant dispersed throughout the web, the impregnant consisting essentially of a blend of a rigid polymeric material and an inorganic filler, in stated proportions, with the impregnant constituting a minor portion of the finished weight of the paper. A process for producing the paper is disclosed.
Inventors
- 👤 William G. Louden
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 08:34
CPC Classifications
D; D21; D21H; D21H17/00; D21H17/20; D21H17/33; D21H17/34
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
203 words
A process for manufacturing dense paper comprising the steps, performed in the following sequence, of: advancing a web of paper having a dry uncalendered density between opposite surfaces in a range of between about 7 to about 11 lbs/mil; impregnating the advancing web by applying to both of said surfaces an excess amount of an aqueous dispersion containing a blend of a rigid polymeric material and an inorganic filler, said blend consisting essentially of from about 35 to about 90% of said polymeric material and from about 10 to about 65% of said inorganic filler, said percentages being by weight based on the weight of the blend, said rigid polymeric material having a glass transition temperature in a range of between about 15 to about 60° C., and passing said advancing web between opposed squeeze rolls to ensure penetration of said web by said dispersion and to remove excess dispersion from said surfaces; and heating said web after it passes between said rolls and said excess dispersion has been removed to fuse said blend in said web in a range of between about 8.5% to about 50%, by weight, of the blend, said weight being based on the dry weight of the web.
Claim 2
Dependent Claim
203 words
A process for manufacturing dense paper comprising the steps, performed in the following sequence, of: advancing a web of paper having a dry uncalendered density between opposite surfaces in a range of between about 7 to about 11 lbs/mil; impregnating the advancing web by applying to both of said surfaces an excess amount of an aqueous dispersion containing a blend of a rigid polymeric material and an inorganic filler, said blend consisting essentially of from about 35 to about 90% of said polymeric material and from about 10 to about 65% of said inorganic filler, said percentages being by weight based on the weight of the blend, said rigid polymeric material having a glass transition temperature in a range of between about 15 to about 60° C., and passing said advancing web between opposed squeeze rolls to ensure penetration of said web by said dispersion and to remove excess dispersion from said surfaces; and heating said web after it passes between said rolls and said excess dispersion has been removed to fuse said blend in said web in a range of between about 8.5% to about 50%, by weight, of the blend, said weight being based on the dry weight of the web.
Claim 3
Dependent Claim
31 words
The process according to claim 1 wherein the density of said paper web prior to impregnation with said blend is in a range of between about 8.5 to about 10.5 lbs./mil.
Claim 4
Dependent Claim
17 words
The process according to claim 1 wherein said web prior to impregnation is substantially free of sizing.
Claim 5
Dependent Claim
28 words
The process according to claim 1 wherein said polymeric material of said blend is selected from the group of materials consisting of polyvinyl acetate, polyacrylate, and polyvinyl chloride.
Claim 6
Dependent Claim
25 words
The process according to claim 1 wherein said inorganic filler is selected from the group of fillers consisting of clay, calcium carbonate, mica, and talc.
Claim 7
Dependent Claim
29 words
The process according to claim 1 wherein said aqueous dispersion contains between about 12.5 and 60%, by weight, of said blend, based on the total weight of said dispersion.
References Cited (Backward Citations)
US3338736A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-11-02 | 1980-05-03 | 1980-11-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-11-02 | 1984-05-03 | 1984-11-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-11-02 | 1988-05-03 | 1988-11-02 | $7700.00 | Window Closed / Lapsed |