US4393103A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Erasable dense paper and improved method of manufacturing
Assignee: Individual
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Filing: 1981-08-28
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Granted: 1983-07-12
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Expires: 2001-08-28
Abstract
Abstract A paper which affords complete erasability of typewriter images is disclosed. The paper comprises a web of cellulosic fibers and a blend of a rigid polymeric material and a compatible filler together with a small but effective amount of tin carried by the web. A process for manufacturing the paper is also disclosed.
Inventors
- 👤 William G. Louden
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 09:20
CPC Classifications
D; D21; D21H; D21H17/00; D21H17/03; D21H17/05; D21H17/12; Y; Y10; Y10T; Y10T428/00; Y10T428/31504; Y10T428/31855; Y10T428/3188; Y10T428/31895; Y10T428/31906
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
189 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 in a range of between about 7 to about 14 lbs./mil.; applying to the advancing web 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, from about 10 to about 65% of said inorganic filler, and an organic compound of tin in a range of about 0.10% to about 2.0%, said percentages being by weight based on the non-tin portion of 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.; removing the excess dispersion from said web; and heating said web after the excess dispersion has been removed to fuse said blend to said web so that the resulting paper comprises 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
189 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 in a range of between about 7 to about 14 lbs./mil.; applying to the advancing web 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, from about 10 to about 65% of said inorganic filler, and an organic compound of tin in a range of about 0.10% to about 2.0%, said percentages being by weight based on the non-tin portion of 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.; removing the excess dispersion from said web; and heating said web after the excess dispersion has been removed to fuse said blend to said web so that the resulting paper comprises 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
35 words
The process according to claim 1 wherein said organic compound of tin is in a range of about 0.10% to about 2.0%, by weight, based on the combined weight of the polymeric material and filler.
Claim 4
Dependent Claim
16 words
The process according to claim 2 wherein said organic compound of tin includes dialkyl tin dicarboxylates.
Claim 5
Dependent Claim
21 words
The process according to claim 3 wherein said dialkyl tin dicarboxylates include an alkyl group having at least four carbon atoms.
Claim 6
Dependent Claim
15 words
The process according to claim 4 wherein said alkyl group has about eight carbon atoms.
Claim 7
Dependent Claim
24 words
The process according to claim 3 wherein said dialkyl tin dicarboxylates include a carboxyl group having a chain of at least twelve carbon atoms.
Claim 8
Dependent Claim
46 words
The process according to claim 3 wherein said dialkyl tin dicarboxylates are selected from the group consisting of dioctyl tin dilaurate, dibutyl tin distearate, dibutyl tin di 2-ethyl-hexoate, dibutyl tin di B-mercapto propionate, dibutyl tin dilaurate, dibutyl tin diacetate, and dioctyl tin di b-isooctyl mercapto acetate.
Claim 9
Dependent Claim
26 words
The process according to claim 1 wherein said compound of tin is selected from the group consisting of dilauryl tin dichloride and tri n-butyl tin oxide.
Claim 10
Dependent Claim
14 words
The process according to claim 1 wherein said blend is impregnated in said web.
Claim 11
Dependent Claim
18 words
The process according to claim 1 wherein said blend is carried predominately on the surface of said web.
Claim 12
Dependent Claim
31 words
The process according to claim 1 wherein the density of said paper web prior to application of said blend is in a range of between about 8.5 to about 10.5 lbs./mil.
Claim 13
Dependent Claim
20 words
The process according to claim 1 wherein said web is substantially free of sizing prior to application of said blend.
Claim 14
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 15
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 16
Dependent Claim
29 words
The process according to claim 1 wherein said aqueous dispersion includes between about 12.5 and 60%, by weight, of said blend, based on the total weight of said dispersion.
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) | 1986-07-11 | 1987-01-10 | 1987-07-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-07-11 | 1991-01-10 | 1991-07-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-07-11 | 1995-01-10 | 1995-07-12 | $7700.00 | Window Closed / Lapsed |