Patent US4163679A successfully refreshed from Google Patents.
US4163679A
Expired / Lapsed
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Aluminum treatment with alkaline solution and tannin
Assignee: Henkel Corp
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Filing: 1978-03-30
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Granted: 1979-08-07
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Expires: 1998-03-30
Abstract
Abstract A chromium-free treatment for aluminum imparts corrosion resistance and paint receptivity to the surface. The process is sequential and includes a first contact with an aqueous alkaline solution (pH above 10) containing complexed iron ion, water rinsing, and then contact with an aqueous acidic organic tannin-containing composition.
Inventors
- 👤 Yoshio Nagae
- 👤 Takashi Utsumi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 19:58
CPC Classifications
C; C23; C23C; C23C22/00; C23C22/05; C23C22/60; C23C22/66
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
72 words
A chromium-free process for imparting corrosion resistance to a surface of aluminum and its alloys, comprising: (a) contacting the surface with an aqueous alkaline solution having a pH value of at least 10 and comprising complexed iron ions in a concentration of at least 0.01 g/l iron; (b) rinsing the surface with water; and (c) contacting the surface with an aqueous acidic solution containing at least 0.01 g/l of an organic tannin.
Claim 2
Dependent Claim
72 words
A chromium-free process for imparting corrosion resistance to a surface of aluminum and its alloys, comprising: (a) contacting the surface with an aqueous alkaline solution having a pH value of at least 10 and comprising complexed iron ions in a concentration of at least 0.01 g/l iron; (b) rinsing the surface with water; and (c) contacting the surface with an aqueous acidic solution containing at least 0.01 g/l of an organic tannin.
Claim 3
Dependent Claim
18 words
The process of claim 1 wherein the alkaline solution exhibits a pH value of from 11.5 to 13.5.
Claim 4
Dependent Claim
18 words
The process of claim 1 wherein the acidic solution exhibits a pH value of from 1.5 to 6.0.
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) | 1982-08-06 | 1983-02-05 | 1983-08-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-08-06 | 1987-02-05 | 1987-08-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-08-06 | 1991-02-05 | 1991-08-07 | $7700.00 | Window Closed / Lapsed |