US4898619A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Pigment compositions
Assignee: Vesuvius Holdings Ltd
•
Filing: 1988-12-19
•
Granted: 1990-02-06
•
Expires: 2008-12-19
Abstract
Abstract A pigment which comprises crystallites of iron oxide having an average particle size of less than 100 nanometers doped with from 10% to 80% by weight of aluminium as Al 3+ based on the weight of iron, having the general formula (Al x Fe 2-x )O 3 , where x=0.34 to 1.24 and having an orange color with the following color measurements: L (Lightness)>45° C (Strength)>40° H (Hue) 50° to 60° A pigment precursor composition is also provided which, on firing, produces the pigment as defined above.
Inventors
- 👤 John F. Clifford
- 👤 Fiona C. R. Morrison
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 08:06
CPC Classifications
C; C01; C01G; C01G49/00; C01G49/0018; C01G49/0045; B; B82; B82Y; B82Y30/00; C09; C09C; C09C1/00; C09C1/22; C09C1/24; C09C1/40; C01P; C01P2002/00; C01P2002/50; C01P2002/52; C01P2002/54; C01P2004/00; C01P2004/01; C01P2004/60; C01P2004/64; C01P2006/00; C01P2006/60; C01P2006/62; C01P2006/65; C01P2006/66
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
42 words
A pigment precursor composition which consists essentially of crystallites of an iron aluminium oxyhydroxide complex having an average particle size of less than 100 nanometres and containing from 10% to 80% by weight of aluminium as Al 3+ based on the iron.
Claim 2
Dependent Claim
42 words
A pigment precursor composition which consists essentially of crystallites of an iron aluminium oxyhydroxide complex having an average particle size of less than 100 nanometres and containing from 10% to 80% by weight of aluminium as Al 3+ based on the iron.
Claim 3
Dependent Claim
22 words
A pigment precursor composition according to claim 1 which contains from 60 to 80% by weight of aluminium as Al 3+ .
Claim 4
Dependent Claim
16 words
A pigment precursor composition according to claim 1 which includes therein a white burning carrier material.
Claim 5
Dependent Claim
26 words
A pigment precursor composition according to claim 3 wherein the carrier material is selected from the group consisting of a white burning clay, silica and alumina.
Claim 6
Dependent Claim
26 words
A pigment precursor composition according to claim 1 wherein the crystallites of the iron aluminium complex have an average particle size of less than 75 nanometers.
Claim 7
Dependent Claim
17 words
A pigment precursor composition according to claim 1 which is in the form of a dry powder.
Claim 8
Dependent Claim
75 words
A pigment which consists essentially of crystallites of iron oxide having an average particle size of less than 100 nanometers doped with from 10% to 80% by weight of aluminium as Al 3+ based on the weight of iron, having the general formula (Al x Fe 2-x )O 3 , where x=0.34 to 1.24 and having an orange colour with the following colour measurements: L (Lightness) >45° C (Strength) >40° H (Hue) 50° to 60°
Claim 9
Dependent Claim
75 words
A pigment which consists essentially of crystallites of iron oxide having an average particle size of less than 100 nanometers doped with from 10% to 80% by weight of aluminium as Al 3+ based on the weight of iron, having the general formula (Al x Fe 2-x )O 3 , where x=0.34 to 1.24 and having an orange colour with the following colour measurements: L (Lightness) >45° C (Strength) >40° H (Hue) 50° to 60°
Claim 10
Dependent Claim
39 words
A pigment according to claim 7 which is doped with from 60 to 80% by weight of aluminium as Al 3+ and has the general formula (Al x Fe 2-x O 3 , where x = 1.10 to 1.24.
Claim 11
Dependent Claim
14 words
A pigment according to claim 7 which includes therein a white burning carrier material.
Claim 12
Dependent Claim
24 words
A pigment according to claim 9 wherein the carrier material is selected from the group consisting of a white burning clay, silica and alumina.
Claim 13
Dependent Claim
22 words
A pigment according to claim 7 wherein the crystallites of iron oxide have an average particle size of less than 75 nanometers.
Claim 14
Dependent Claim
16 words
A pigment according to claim 7 wherein the aluminium as dopant is present as aluminium oxide.
Claim 15
Dependent Claim
64 words
A method for the preparation of a pigment precursor composition according to claim 1, which method comprises, forming an aqueous solution containing aluminium (Al 3+ ) cations and iron (Fe 3+ ) cations, optionally in the presence of a white burning carrier material, and raising the pH of the aqueous solution to above pH 1.5 in order to precipitate an iron aluminium complex therefrom.
Claim 16
Dependent Claim
26 words
A method according to claim 13 wherein a solution containing aluminium (Al 3+ ) cations is added to a solution containing iron (Fe 3+ ) cations.
Claim 17
Dependent Claim
42 words
A method according to claim 13 wherein the pH of the solution containing Al 3+ and Fe 3+ cations is adjusted by the addition of a base selected from the group consisting of an organic base and an alkali metal hydroxide thereto.
Claim 18
Dependent Claim
25 words
A method according to claim 13 wherein the pH of the mixture is raised to a pH in the range of from 1.5 to 6.5.
Claim 19
Dependent Claim
54 words
A method according to claim 13 wherein the Fe 3+ cations are provide by a ferric salt selected from the group consisting of ferric chloride, ferric sulphate and ferric acetate and the Al 3+ cations are provided by an aluminium salt selected from the group consisting of aluminium chloride, aluminium sulphate and aluminium acetate.
Claim 20
Dependent Claim
24 words
A method according to claim 13 wherein the precipitate is separated from the suspension and dried in air at a temperature below 200° C.
Claim 21
Dependent Claim
56 words
A method for the preparation of a pigment according to claim 7 which comprises firing a pigment precursor composition according to claim 1 at a temperature in the range of from 700° to 1200° C. to provide an orange pigment with the following colour measurements: L (Lightness) >45° C (Strength) >40° H (Hue) 50° to 60°.
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) | 1993-02-05 | 1993-08-07 | 1994-02-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-02-05 | 1997-08-07 | 1998-02-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-02-05 | 2001-08-07 | 2002-02-06 | $7700.00 | Window Closed / Lapsed |