Patent US5647902A successfully refreshed from Google Patents.
US5647902A
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Stabilized calcium carbonate composition using sodium carbonate and mixtures of acids and uses therefor
Assignee: Imerys Minerals USA Inc
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Filing: 1995-10-20
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Granted: 1997-07-15
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Expires: 2015-10-20
Abstract
Abstract An improved form of calcium carbonate which is acid resistant to enable its use as a filler material in the making of neutral to weakly acid paper, and a process for producing this acid resistant calcium carbonate are provided. This acid resistant calcium carbonate comprises a mixture of at least about 0.1 percent, based on the dry weight of the calcium carbonate, of sodium carbonate, together with at least about 0.1 percent, based on the dry weight of the calcium carbonate, of a mixture of weak acids in admixture with the calcium carbonate.
Inventors
- 👤 Kuan-Ting Wu
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 01:58
CPC Classifications
C; C09; C09C; C09C1/00; C09C1/02; C09C1/021; C01; C01F; C01F11/00; C01F11/18; C01F11/185; C09C3/00; C09C3/10; C01P; C01P2004/00; C01P2004/30; C01P2006/00; C01P2006/22; C01P2006/60
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
58 words
An acid resistant calcium carbonate comprising a mixture of about 1 to about 6 percent, based on the dry weight of the calcium carbonate, of sodium carbonate together with at least about 0.1 percent, based on the dry weight of the calcium carbonate, of a mixture of two or more weak acids, in admixture with the calcium carbonate.
Claim 2
Dependent Claim
58 words
An acid resistant calcium carbonate comprising a mixture of about 1 to about 6 percent, based on the dry weight of the calcium carbonate, of sodium carbonate together with at least about 0.1 percent, based on the dry weight of the calcium carbonate, of a mixture of two or more weak acids, in admixture with the calcium carbonate.
Claim 3
Dependent Claim
26 words
The acid resistant calcium carbonate of claim 1 wherein the weak acids are selected from the group consisting of polyacrylic acid, polymaleic acid and phosphoric acid.
Claim 4
Dependent Claim
22 words
The acid resistant calcium carbonate of claim 2 wherein the mixture of weak acids is comprised of polyacrylic acid and phosphoric acid.
Claim 5
Dependent Claim
22 words
The acid resistant calcium carbonate of claim 2 wherein the mixture of weak acids is comprised of polymaleic acid and phosphoric acid.
Claim 6
Dependent Claim
35 words
The acid resistant calcium carbonate of claim 1 wherein the mixture of weak acids is present in an amount of about 1 to about 8 percent, based on the dry weight of the calcium carbonate.
Claim 7
Dependent Claim
77 words
A process for the preparation of an acid resistant calcium carbonate which comprises: a) forming a mixture of calcium carbonate with about 1 to about 6 percent, based on the dry weight of the calcium carbonate, of sodium carbonate: b) adding at least about 0.1 percent, based on the dry weight of the calcium carbonate, of a mixture of two or more weak acids to the mixture; and c) blending the resultant mixture to ensure uniform mixing.
Claim 8
Dependent Claim
77 words
A process for the preparation of an acid resistant calcium carbonate which comprises: a) forming a mixture of calcium carbonate with about 1 to about 6 percent, based on the dry weight of the calcium carbonate, of sodium carbonate: b) adding at least about 0.1 percent, based on the dry weight of the calcium carbonate, of a mixture of two or more weak acids to the mixture; and c) blending the resultant mixture to ensure uniform mixing.
Claim 9
Dependent Claim
27 words
The process according to claim 6 wherein the weak acids of the mixture are selected from the group consisting of polyacrylic acid, polymaleic acid and phosphoric acid.
Claim 10
Dependent Claim
20 words
The process according to claim 7 wherein the mixture of weak acids is comprised of polyacrylic acid and phosphoric acid.
Claim 11
Dependent Claim
20 words
The process according to claim 7 wherein the mixture of weak acids is comprised of polymaleic acid and phosphoric acid.
Claim 12
Dependent Claim
33 words
The process according to claim 7 wherein the mixture of weak acids is present in an amount of about 1 to about 8 percent, based on the dry weight of the calcium carbonate.
Claim 13
Independent Claim
74 words
A method of improving the optical properties of neutral to weakly acidic paper by the addition of an acid resistant calcium carbonate comprising a mixture of at least about 0.1 percent, based on the dry weight of the calcium carbonate, of sodium carbonate together with at least about 0.1 percent, based on the dry weight of the calcium carbonate, of a mixture of two or more weak acids, in admixture with the calcium carbonate.
Claim 14
Independent Claim
74 words
A method of improving the optical properties of neutral to weakly acidic paper by the addition of an acid resistant calcium carbonate comprising a mixture of at least about 0.1 percent, based on the dry weight of the calcium carbonate, of sodium carbonate together with at least about 0.1 percent, based on the dry weight of the calcium carbonate, of a mixture of two or more weak acids, in admixture with the calcium carbonate.
References Cited (Backward Citations)
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| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2000-07-14 | 2001-01-13 | 2001-07-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2004-07-14 | 2005-01-13 | 2005-07-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2008-07-14 | 2009-01-13 | 2009-07-15 | $7700.00 | Window Closed / Lapsed |