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US5128169A
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Method for forming hydroxyapatite coating film
Assignee: Sumitomo Chemical Co Ltd
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Filing: 1991-01-02
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Granted: 1992-07-07
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Expires: 2011-01-02
Abstract
Abstract A method for forming a hydroxyapatite coating film on a substrate which comprises coating a dispersion of flocculated colloids of hydroxyapatite on a substrate and drying. The coating method of this invention does not require heating of the coated substrate to high temperature and hence can also be applied to a substrate which is easily deteriorated with heat. The coated substrate of this invention has excellent strength and adhesion force and is useful in a variety of fields, particularly as an implant and as a material, adsorbing and separating agent.
Inventors
- 👤 Kenji Saita
- 👤 Shinji Fujiwara
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 18:18
CPC Classifications
A; A61; A61L; A61L27/00; A61L27/28; A61L27/30; A61L27/32; A61F; A61F2310/00; A61F2310/00389; A61F2310/00592; A61F2310/00796
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
65 words
A method for forming a hydroxyapatite coating film on a substrate, which comprises coating a dispersion of flocculated colloids of hydroxyapatite having a sedimentation volume of more than 27 ml/g onto a substrate, and drying the coated substrate, wherein the dispersion is prepared by forming sediment of flocculated colloids of hydroxyapatite in a supernatent liquor, removing said supernatant liquor, and, without drying, dispersing the sediment.
Claim 2
Independent Claim
65 words
A method for forming a hydroxyapatite coating film on a substrate, which comprises coating a dispersion of flocculated colloids of hydroxyapatite having a sedimentation volume of more than 27 ml/g onto a substrate, and drying the coated substrate, wherein the dispersion is prepared by forming sediment of flocculated colloids of hydroxyapatite in a supernatent liquor, removing said supernatant liquor, and, without drying, dispersing the sediment.
Claim 3
Dependent Claim
44 words
The method according to claim 1, wherein the flocculated colloids of hydroxyapatite are prepared by mixing an aqueous solution of a calcium salt at a concentration of 0.0005 to 0.6M, and an aqueous solution of a phosphate at a concentration of 0.0003 to 0.4M.
Claim 4
Dependent Claim
26 words
The method according to claim 2, wherein the calcium salt and the phosphate are mixed in an atomic ratio of Ca/P equal to 1.5 to 2.0.
Claim 5
Dependent Claim
25 words
The method according to claim 2, wherein the mixing of the calcium and phosphate salts is carried out at a pH of 6 to 13.
Claim 6
Dependent Claim
21 words
The method according to claim 1, wherein the dispersion of flocculated colloids has a sedimentation volume of 40 to 150 ml/g.
Claim 7
Dependent Claim
20 words
The method according to claim 1, wherein the coated substrate is dried at a temperature of 150° to 200° C.
Claim 8
Dependent Claim
36 words
The method according to claim 1, wherein the sediment of flocculated colloids of hydroxyapatite in a supernatant liquor is formed by mixing an aqueous solution of a calcium salt and an aqueous solution of a phosphate.
Claim 9
Dependent Claim
24 words
The method according to claim 1, wherein the hydroxyapatite has a particle size of 0.1 to 1 microns when measured by a sedimentation method.
Claim 10
Dependent Claim
18 words
The method according to claim 1, wherein the calcium salt is a chloride, nitrate, acetate or hydroxide salt.
Claim 11
Dependent Claim
17 words
The method according to claim 2, wherein the phosphate salt is a potassium, sodium or ammonium salt.
Claim 12
Dependent Claim
15 words
The method according to claim 2, wherein the calcium salt concentration is 0.003 to 0.06M.
Claim 13
Dependent Claim
15 words
The method according to claim 2, wherein the phosphate salt concentration is 0.002 to 0.04M.
Claim 14
Dependent Claim
27 words
The method according to claim 2, wherein the calcium salt and the phosphate salt are mixed in an atomic ratio of Ca/P equal to 1.6 to 1.7.
Claim 15
Dependent Claim
25 words
The method according to claim 2, wherein the mixing of the calcium and phosphate salts is carried out at a pH of 7 to 12.
Claim 16
Dependent Claim
29 words
The method according to claim 2, wherein the mixture of calcium and phosphate salts is treated by heating at a temperature in the range of 60° to 100° C.
Claim 17
Dependent Claim
29 words
The method according to claim 2, wherein the mixture of calcium and phosphate salts is treated by heating at a temperature in the range of 80° to 100° C.
Claim 18
Dependent Claim
15 words
The method according to claim 2, wherein the substrate has a surface which is hydrophilic.
Claim 19
Dependent Claim
14 words
The method according to claim 2, wherein the substrate is metallic, ceramic or glass.
Claim 20
Independent Claim
112 words
A method for forming a hydroxyapatite coating on a substrate, which comprises: preparing a dispersion by mixing an aqueous solution of a calcium salt at a concentration of 0.0005 to 0.6M with an aqueous solution of a phosphate at a concentration of 0.0003 to 0.4M at a pH of 6 to 13 so as to cause sedimentation of flocculated colloids of hydroxyapatite in a supernatant liquor, removing said supernatant liquor, and, without drying, dispersing the sediment so as to form a dispersion of flocculated colloids of hydroxyapatite having a sedimentation volume of more than 27 ml/g; coating said dispersion on a substrate to form a coated substrate; and drying said coated substrate.
Claim 21
Independent Claim
112 words
A method for forming a hydroxyapatite coating on a substrate, which comprises: preparing a dispersion by mixing an aqueous solution of a calcium salt at a concentration of 0.0005 to 0.6M with an aqueous solution of a phosphate at a concentration of 0.0003 to 0.4M at a pH of 6 to 13 so as to cause sedimentation of flocculated colloids of hydroxyapatite in a supernatant liquor, removing said supernatant liquor, and, without drying, dispersing the sediment so as to form a dispersion of flocculated colloids of hydroxyapatite having a sedimentation volume of more than 27 ml/g; coating said dispersion on a substrate to form a coated substrate; and drying said coated substrate.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1995-07-07 | 1996-01-06 | 1996-07-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1999-07-07 | 2000-01-06 | 2000-07-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2003-07-07 | 2004-01-06 | 2004-07-07 | $7700.00 | Window Closed / Lapsed |