US3898356A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of deacidifying paper
Assignee: Library of Congress
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Filing: 1974-02-28
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Granted: 1975-08-05
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Expires: 1994-02-28
Abstract
Abstract A method of deacidifying paper wherein paper in serial order is contacted with a saturated aqueous solution of a group II metal salt and another aqueous solution capable of forming a substantially insoluble buffer material in situ with the group II metal and subsequently washing out soluble reaction products in a controlled wash.
Inventors
- 👤 John C Williams
- 👤 Jr George B Kelly
- 👤 Richard L Best
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 23:08
CPC Classifications
D; D21; D21H; D21H25/00; D21H25/18; D21H11/00; D21H11/02; D21H11/04; D21H11/14; D21H17/00; D21H17/03; D21H17/05; D21H17/06; D21H17/62; D21H17/63; D21H17/66; D21H17/70; D21H21/00; D21H21/14; D21H21/36
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
91 words
A METHOD OF NEUTRALIZING THE ACIDITY OF PAPER AND BUFFERING IT ON THE ALKALINE SIDE WHEREIN THE PAPER TO BE TREATED IN SERIAL ORDER IS CONTACTED WITH AN AQUEOUS SOLUTION OF A GROUP II METAL SALT AND AN AQUEOUS SOLUTION OF A REACTANT MATERIAL CAPABLE OF INTERACTING WITH THE GROUP II METAL TO FORM A RELATIVELY WATER-INSOLUBLE BUFFERING MATERIAL, PERMITTING INTERACTION OF SAID SOLUTIONS TO FORM SAID BUFFERING MATERIAL, WASHING THE TREATED PAPER WITH A CONTROLLED WASH TO REMOVE EXCESS TREATING AGENTS AND SOLUBLE REACTION PRODUCTS AND DRYING SAID TREATED PAPER.
Claim 2
Independent Claim
91 words
A METHOD OF NEUTRALIZING THE ACIDITY OF PAPER AND BUFFERING IT ON THE ALKALINE SIDE WHEREIN THE PAPER TO BE TREATED IN SERIAL ORDER IS CONTACTED WITH AN AQUEOUS SOLUTION OF A GROUP II METAL SALT AND AN AQUEOUS SOLUTION OF A REACTANT MATERIAL CAPABLE OF INTERACTING WITH THE GROUP II METAL TO FORM A RELATIVELY WATER-INSOLUBLE BUFFERING MATERIAL, PERMITTING INTERACTION OF SAID SOLUTIONS TO FORM SAID BUFFERING MATERIAL, WASHING THE TREATED PAPER WITH A CONTROLLED WASH TO REMOVE EXCESS TREATING AGENTS AND SOLUBLE REACTION PRODUCTS AND DRYING SAID TREATED PAPER.
Claim 3
Dependent Claim
16 words
The method of claim 1 wherein the controlled wash has a pH of 7 or above.
Claim 4
Dependent Claim
15 words
The method of claim 2 wherein the controlled wash is saturated with the buffering material.
Claim 5
Dependent Claim
25 words
The method of claim 1 wherein the group II metal salt is selected from the group of an alkaline earth halide and alkaline earth acetate.
Claim 6
Dependent Claim
11 words
The method of claim 4 wherein the halide is the chloride.
Claim 7
Dependent Claim
13 words
The method of claim 4 wherein the alkaline earth halide is calcium chloride.
Claim 8
Dependent Claim
13 words
The method of claim 1 wherein the reactant solution is a soluble carbonate.
Claim 9
Dependent Claim
11 words
The method of claim 7 wherein the carbonate is ammonium carbonate.
Claim 10
Dependent Claim
19 words
The method of claim 2 wherein the first solution is calcium chloride and the second solution is ammonium carbonate.
Claim 11
Dependent Claim
19 words
The method of claim 3 wherein the first solution is calcium chloride and the second solution is ammonium carbonate.
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) | 1978-08-04 | 1979-02-03 | 1979-08-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-08-04 | 1983-02-03 | 1983-08-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-08-04 | 1987-02-03 | 1987-08-05 | $7700.00 | Window Closed / Lapsed |