US3909277A
Expired / Lapsed
US
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Lead containing ceramic compositions which further contain a lead release inhibiting amount of a chromium compound
Assignee: Heritage Silversmiths Ltd
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Filing: 1973-06-26
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Granted: 1975-09-30
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Expires: 1993-06-26
Abstract
Abstract Lead release from copper oxide colored- and lead oxidecontaining glazes for pottery is lowered by incorporation in the glass of a small amount of certain chromium compounds, particuarly earth metal chromates.
Inventors
- 👤 Alfred Dube
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 11:23
CPC Classifications
C; C03; C03C; C03C3/00; C03C3/04; C03C3/062; C03C3/07; C03C3/072; C03C8/00; C03C8/02; C03C8/10; C03C8/14
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
193 words
IN A LEAD-RELEASING COLORED CEAMIC COMPOSITION FORMED FROM A PLURALITY OF GLASS-FORMING COMPONENTS INCLUDING A COPPER OXIDE-PROVIDING MATERIAL PRESENT IN AN AMOUNT SUFFICIENT TO PROVIDE UP TO ABOUT 3% BY WEIGHT OF COPPER OXIDE BASED ON THE TOTAL WEIGHT OF THE COMPOSITION, A LEAD OXIDEPROVIDING MATERIAL PRESENT IN AN AMOUNT SUFFICIENT TO PROVIDE UP TO ABOUT 40% BY WEIGHT OF LEAD OXIDE BASED ON THE TOTAL WEIGHT OF THE COMPOSITION, AT LEAST ONE FLUXING OXIDE-PROVIDING MATERIAL PRESENT IN SUFFICIENT AMOUNT TO PROVIDE UP TO ABOUT 25% BY WEIGHT OF FLUXING OXIDES, AND A SILICA-FORMING MATERIAL PRESENT IN AN AMOUNT SUFFICIENT TO PROVIDE THE BALANCE BY WEIGHT OF THE GLASS-ORMING COMPONENTS OF SILICA, THE IMPROVEMENT WHICH COMPRISES ADDING TO SAID PLURALITY OF GLASS-FORMING COMPONENTS A CHROMIUM COMPOUND SELECTED FROM THE GROUP CONSISTING OF BARIUM CHROMATE, CALCIUM CHROMATE, STRONTIUM CHROMATE, IRON CHROMATE, COBALT CHROMATE, SILVER CHROMATE, CUPRIC CHROMATE, ZINC CHROMATE AND CHROMIC OXIDE, SAID CHROMIUM COMPOUND BEING ADDED IN AN AMOUNT SUFFICIENT TO EFFECT A LEAD RELEASE OF LESS THAN 7 PPM AND IN AN AMOUNT INSUFFICIENT TO ALTER SUBSTANTIALLY THE COLOR AND VISUAL APPEARANCE OF SAID COMPOSITION IN THE ABSENCE OF SUCH CHROMIUM COMPOUND.
Claim 2
Dependent Claim
193 words
IN A LEAD-RELEASING COLORED CEAMIC COMPOSITION FORMED FROM A PLURALITY OF GLASS-FORMING COMPONENTS INCLUDING A COPPER OXIDE-PROVIDING MATERIAL PRESENT IN AN AMOUNT SUFFICIENT TO PROVIDE UP TO ABOUT 3% BY WEIGHT OF COPPER OXIDE BASED ON THE TOTAL WEIGHT OF THE COMPOSITION, A LEAD OXIDEPROVIDING MATERIAL PRESENT IN AN AMOUNT SUFFICIENT TO PROVIDE UP TO ABOUT 40% BY WEIGHT OF LEAD OXIDE BASED ON THE TOTAL WEIGHT OF THE COMPOSITION, AT LEAST ONE FLUXING OXIDE-PROVIDING MATERIAL PRESENT IN SUFFICIENT AMOUNT TO PROVIDE UP TO ABOUT 25% BY WEIGHT OF FLUXING OXIDES, AND A SILICA-FORMING MATERIAL PRESENT IN AN AMOUNT SUFFICIENT TO PROVIDE THE BALANCE BY WEIGHT OF THE GLASS-ORMING COMPONENTS OF SILICA, THE IMPROVEMENT WHICH COMPRISES ADDING TO SAID PLURALITY OF GLASS-FORMING COMPONENTS A CHROMIUM COMPOUND SELECTED FROM THE GROUP CONSISTING OF BARIUM CHROMATE, CALCIUM CHROMATE, STRONTIUM CHROMATE, IRON CHROMATE, COBALT CHROMATE, SILVER CHROMATE, CUPRIC CHROMATE, ZINC CHROMATE AND CHROMIC OXIDE, SAID CHROMIUM COMPOUND BEING ADDED IN AN AMOUNT SUFFICIENT TO EFFECT A LEAD RELEASE OF LESS THAN 7 PPM AND IN AN AMOUNT INSUFFICIENT TO ALTER SUBSTANTIALLY THE COLOR AND VISUAL APPEARANCE OF SAID COMPOSITION IN THE ABSENCE OF SUCH CHROMIUM COMPOUND.
Claim 3
Dependent Claim
26 words
The composition of claim 1, wherein said chromium compound is present in an amount of less than about 1% by weight of said plurality of components.
Claim 4
Dependent Claim
32 words
The composition of claim 1, wherein said chromium compound is present in an amount of from about 0.25 to about 0.75% by weight of the toTal weight of said plurality of components.
Claim 5
Dependent Claim
30 words
The composition of claim 1, wherein said chromium compound is selected from strontium chromate and calcium chromate present in an amount of from about 0.25 to about 0.75% by weight.
Claim 6
Dependent Claim
25 words
The composition of claim 1, wherein said chromium compound is barium chromate present in an amount of from about 0.50 to about 0.75% by weight.
Claim 7
Dependent Claim
25 words
The composition of claim 1, wherein said chromium compound is iron chromate present in an amount of from about 0.25 to about 0.50% by weight.
Claim 8
Dependent Claim
25 words
The composition of claim 1, wherein said chromium compound is cobalt chromate present in an amount of from about 0.50 to about 0.75% by weight.
Claim 9
Dependent Claim
24 words
The composition of claim 1, wherein said chromium compound is silver chromate present in an amount of about 0.25 to about 0.50% by weight.
Claim 10
Dependent Claim
21 words
The composition of claim 1, wherein said chromium compound is cupric chromate present in an amount of about 0.75% by weight.
Claim 11
Dependent Claim
21 words
The composition of claim 1, wherein said chromium compound is zinc chromate present in an amount of about 0.25% by weight.
Claim 12
Dependent Claim
23 words
The composition of claim 1, wherein said chromium compound is chromium oxide present in an amount of from about 0.38 to about 0.75%.
Claim 13
Dependent Claim
26 words
The composition of claim 1, wherein said copper oxide-providing material is cupric carbonate present in an amount of less than 5% by weight of said components.
Claim 14
Dependent Claim
25 words
The composition of claim 12, wherein said cupric carbonate is present in an amount from about 2% to about 4% by weight of said components.
Claim 15
Dependent Claim
32 words
The composition of claim 1 wherein said copper oxide-providing material is cuprous oxide or cupric oxide present in an amount of from about 1 to about 3% by weight of said components.
Claim 16
Dependent Claim
64 words
The composition of claim 1, wherein said colored ceramic composition is formed from a plurality of glassforming components including copper carbonate present in an amount from about 2 to about 3% by weight of said components, a lead oxide-providing material present in an amount sufficient to provide about 10 to about 37% by weight of the total weight of said composition of lead oxide.
Claim 17
Dependent Claim
24 words
The composition of claim 15, wherein said chromium compound is calcium chromate present in an amount of about 0.75% by weight of said components.
Claim 18
Dependent Claim
26 words
The composition of claim 15 wherein said chromium compound is strontium chromate present in an amount of about 0.50 to 0.75% by weight of said components.
Claim 19
Dependent Claim
24 words
The composition of claim 15 wherein said chromium compound is iron chromate present in an amount of about 0.50% by weight of said composition.
Claim 20
Dependent Claim
173 words
A glaze forming aqueous slip for pottery, said glaze after firing having a lead release less than 7 ppm, comprising: a. water; b. about 72 to 90% by weight of total solids of a particularized uncolored glass frit containing about 10 to about 37% by weight of lead oxide; c. from about 2% to about 3% by weight of total solids of powder copper carbonate; d. about 5 to about 15% by weight of clay in particulate form; and e. less than 1% by weight of the total solids weight of components (b), (c) and (d) of a chromium compound selected from the group consisting of: i. about 0.25 to about 0.75% by weight of calcium chromate; ii. about 0.50 to about 0.75% by weight of barium chromate; iii. about 0.25 to about 0.75% by weight of strontium chromate; iv. about 0.25 to about 0.50% by weight of iron chromate; v. about 0.25% to about 0.50% by weight of silver chromate, and vi. about 0.50% to about 0.75% by weight of cobalt chromate.
Claim 21
Dependent Claim
173 words
A glaze forming aqueous slip for pottery, said glaze after firing having a lead release less than 7 ppm, comprising: a. water; b. about 72 to 90% by weight of total solids of a particularized uncolored glass frit containing about 10 to about 37% by weight of lead oxide; c. from about 2% to about 3% by weight of total solids of powder copper carbonate; d. about 5 to about 15% by weight of clay in particulate form; and e. less than 1% by weight of the total solids weight of components (b), (c) and (d) of a chromium compound selected from the group consisting of: i. about 0.25 to about 0.75% by weight of calcium chromate; ii. about 0.50 to about 0.75% by weight of barium chromate; iii. about 0.25 to about 0.75% by weight of strontium chromate; iv. about 0.25 to about 0.50% by weight of iron chromate; v. about 0.25% to about 0.50% by weight of silver chromate, and vi. about 0.50% to about 0.75% by weight of cobalt chromate.
Claim 22
Dependent Claim
18 words
The slip of claim 19 wherein said glaze has a coefficient of expansion substantially that of the pottery.
References Cited (Backward Citations)
US748851A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-09-29 | 1979-03-31 | 1979-09-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-09-29 | 1983-03-31 | 1983-09-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-09-29 | 1987-03-31 | 1987-09-30 | $7700.00 | Window Closed / Lapsed |