US3923968A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of preparing titanium dioxide pigment
Assignee: Dow Chemical Co
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Filing: 1973-03-01
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Granted: 1975-12-02
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Expires: 1993-03-01
Abstract
Abstract Elongate monocrystalline rutile nucleus crystals are mixed with an acidic titanium chloride solution which contains from 0.1 to 60 grams of dissolved titanium per liter, from 0.004 to 9 gram ions of chloride per liter and little or no phosphate, sulphate or bisulphate. The mixture is heated at a temperature of from 80* to 150*C., thereby producing composite titanium dioxide pigment particles consisting each of one or more nucleus crystals surrounded by elongate rutile crystallites in generally parallel array together with interstitial non-rutile titanium dioxide. The pigment particles have aspect ratios of from 3 to 150, effective diameters of from 0.05 to 0.3 microns and contain not more than about 10 weight percent of the non-rutile titanium dioxide.
Inventors
- 👤 Max G Basque
- 👤 James E Magner
- 👤 Joseph P Surls
- 👤 Ben F West
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 12:23
CPC Classifications
C; C01; C01G; C01G23/00; C01G23/04; C01G23/047; C01G23/053; C01G23/0536; C01G23/0538; B; B82; B82Y; B82Y30/00; C01P; C01P2004/00; C01P2004/54; C01P2004/60; C01P2004/61; C01P2004/62; C01P2004/64; C01P2006/00; C01P2006/60
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
246 words
A PROCESS FOR THE PREPARATION OF COMPOSITE TITANIUM DIOXIDE PIGMENT PARTICLES, EACH CONSISTING OF ONE OR MORE ELONGATE RUTILE MONOCRYSTALS HAVING LENGTHS WITHIN THE RANGE OF FROM 0.15 TO 15 MICRONS, DIAMETERS WITHIN THE RANGE OF 0.01 TO 0.1 MICRONS AND ASPECT RATIOS OF FROM 5 TO 200, SURROUNDED BY SIMILARLY ELONGA!ED RUTILE CRYSTALLITES HAVING LENGTHS WITHIN THE RANGE OF 0.005 TO 0.05 MICRONS, DIAMETERS WITHIN THE RANGE OF 0.01 TO 0.1 MICRONS AND ASPECT RATIOS OF FROM 5 TO 50 AND FROM 1 TO 10 VOLUME PERCENT OF INTERSTITIAL NON-RUTILE TITANIUM DIOXIDE, WHICH COMPRISES: CONTACTING SAID RUTILE MONOCRYSTALS FOR AT LEAST 3 MINUTES WITH AN ACIDIC AQUWOUA TITANIUM CHLORIDE SOLUTION UNDER AT LEAST AUTOGENOUS PRESSURE AND AT A TEMPERATURE OF FROM 80* TO 150*C., THEREBY CAUSING CROSS-SECTIONAL PARTICLES GROWTH BY DEPOSITION ON SID MONOCRYSTALS OF TITANIUM DIOXIDE HYDROLYSATE IN THE FORM OF SAID CRYSTALLITIES DISPOSED WITH SAID INTERSTITIAL TITANIUM DIOXIDE AROUND SAID MONOCRYSTALS IN A CONFIGURATION GENERALLY PARALLEL THERETO AND CONTAINUING SAID CONTACT UNTIL A GROWTH RATIO OF UP TO ABOUT 18 HAS BEEN ACHIEVED; SAID SOLUTION CONTAINING FROM 0.1 TO 60 GRAMS OF DISSOLVED TITANIUM PER LITER, FROM 0.004 TO 9 GRAM IONS OF CHLORIDE PER LITER, NOT MORE THAN 0.001 GRAMS IONS OF PHOSPHATE PER LITER AND NOT MORE THAN 0.01 GRAM IONS OF SULPHATE AND/OR BISULPHATE PER LITER; AND THE WIEGHT OF TITANIUM PRESENT IN SAID MONOCRYSTALS BEING FROM 1 TO 50 PERCENT OF THE WEIGHT OF DISSOLVED TITANIUM IN SAID SOLUTION
Claim 2
Dependent Claim
246 words
A PROCESS FOR THE PREPARATION OF COMPOSITE TITANIUM DIOXIDE PIGMENT PARTICLES, EACH CONSISTING OF ONE OR MORE ELONGATE RUTILE MONOCRYSTALS HAVING LENGTHS WITHIN THE RANGE OF FROM 0.15 TO 15 MICRONS, DIAMETERS WITHIN THE RANGE OF 0.01 TO 0.1 MICRONS AND ASPECT RATIOS OF FROM 5 TO 200, SURROUNDED BY SIMILARLY ELONGA!ED RUTILE CRYSTALLITES HAVING LENGTHS WITHIN THE RANGE OF 0.005 TO 0.05 MICRONS, DIAMETERS WITHIN THE RANGE OF 0.01 TO 0.1 MICRONS AND ASPECT RATIOS OF FROM 5 TO 50 AND FROM 1 TO 10 VOLUME PERCENT OF INTERSTITIAL NON-RUTILE TITANIUM DIOXIDE, WHICH COMPRISES: CONTACTING SAID RUTILE MONOCRYSTALS FOR AT LEAST 3 MINUTES WITH AN ACIDIC AQUWOUA TITANIUM CHLORIDE SOLUTION UNDER AT LEAST AUTOGENOUS PRESSURE AND AT A TEMPERATURE OF FROM 80* TO 150*C., THEREBY CAUSING CROSS-SECTIONAL PARTICLES GROWTH BY DEPOSITION ON SID MONOCRYSTALS OF TITANIUM DIOXIDE HYDROLYSATE IN THE FORM OF SAID CRYSTALLITIES DISPOSED WITH SAID INTERSTITIAL TITANIUM DIOXIDE AROUND SAID MONOCRYSTALS IN A CONFIGURATION GENERALLY PARALLEL THERETO AND CONTAINUING SAID CONTACT UNTIL A GROWTH RATIO OF UP TO ABOUT 18 HAS BEEN ACHIEVED; SAID SOLUTION CONTAINING FROM 0.1 TO 60 GRAMS OF DISSOLVED TITANIUM PER LITER, FROM 0.004 TO 9 GRAM IONS OF CHLORIDE PER LITER, NOT MORE THAN 0.001 GRAMS IONS OF PHOSPHATE PER LITER AND NOT MORE THAN 0.01 GRAM IONS OF SULPHATE AND/OR BISULPHATE PER LITER; AND THE WIEGHT OF TITANIUM PRESENT IN SAID MONOCRYSTALS BEING FROM 1 TO 50 PERCENT OF THE WEIGHT OF DISSOLVED TITANIUM IN SAID SOLUTION
Claim 3
Dependent Claim
29 words
maintaining said mixture at a temperature of from 100* to 150*C. under at least autogenous pressure from from 1 to 2 hours, thereby producing a polycrystalline titanium dioxide hydrolysate,
Claim 4
Dependent Claim
29 words
maintaining said mixture at a temperature of from 100* to 150*C. under at least autogenous pressure from from 1 to 2 hours, thereby producing a polycrystalline titanium dioxide hydrolysate,
Claim 5
Dependent Claim
12 words
The process of claim 1 additionally comprising preparing said rutile monocrystals by
Claim 6
Dependent Claim
25 words
The process of claim 1 in which the rutile monocrystals have diameters of from 0.01 to 0.04 microns and lengths of at least 1 micron.
Claim 7
Dependent Claim
65 words
converting the polycrystalline hydrolysate formed in the preceding step (2) to said rutile monocrystals by contacting it at a temperature of from 200* to 250*C. under at least autogenous pressure for from 1/4 to 4 hours with an aqueous acid selected from the group consisting of 0.01 to 5.5 molar hydrochloric acid, 0.01 to 20 molar nitric acid and 0.01 to 20 molar perchloric acid.
Claim 8
Dependent Claim
65 words
converting the polycrystalline hydrolysate formed in the preceding step (2) to said rutile monocrystals by contacting it at a temperature of from 200* to 250*C. under at least autogenous pressure for from 1/4 to 4 hours with an aqueous acid selected from the group consisting of 0.01 to 5.5 molar hydrochloric acid, 0.01 to 20 molar nitric acid and 0.01 to 20 molar perchloric acid.
Claim 9
Dependent Claim
27 words
The process of claim 1 in which said contacting is discontinued when said resultant particles have attained an average effective diameter of from 0.08 to 0.12 microns.
Claim 10
Dependent Claim
73 words
The process of claim 1 in which the chloride concentration in said solution is from 5 to 7 gram ions per liter, the dissolved titanium concentration is from 5 to 30 grams per liter, the weight of titanium in the monocrystals is from 5 to 20 percent of the weight of the dissolved titanium and the contacting is continued for from 1/2 to 2 hours at a temperature of from 130* to 150*C.
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) | 1978-12-01 | 1979-06-02 | 1979-12-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-12-01 | 1983-06-02 | 1983-12-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-12-01 | 1987-06-02 | 1987-12-02 | $7700.00 | Window Closed / Lapsed |