Claims
- 1. A steel plate with an organic coating having improved corrosion resistance in its as-worked state, comprising:
- a steel substrate;
- a zinc or zinc alloy-plated layer on the steel substrate;
- a chromate film deposited on the zinc or zinc alloy-plated layer to a coating weight of 5 to 500 mg/m.sup.2 in terms of metallic chromium; and
- a solid organic film deposited on the chromate film to a coating weight of 0.3 to 4.0 g/m.sup.2 by applying an organic coating composition on the chromate film;
- said organic coating composition having been prepared by
- mixing 100 parts by weight of epichlorohydrin-bisphenol A epoxy resin and 10 to 100 parts by weight of an isocyanate compound to produce a urethanated epoxy resin having an epoxy equivalent of 1,000 to 5,000,
- adding 0.5 to 1.0 mole of a dialkanolamine per equivalent of the epoxy group of the urethanated epoxy resin to produce a dialkanolamine-modified urethanated epoxy resin, and
- mixing 100 parts by weight of the dialkanolamine-modified urethanated epoxy resin with 10 to 150 parts by weight of silica on a solid basis to produce the organic coating composition.
- 2. A steel plate according to claim 1 wherein said chromate film is deposited to a coating weight of 10 to 200 mg/m.sup.2 in terms of metallic chromium.
- 3. A steel plate according to claim 1 wherein said solid organic film is deposited to a coating weight of 0.5 to 2.0 g/m.sup.2.
- 4. A steel plate according to claim 1 wherein said dialkanolamine is at least one member selected from the group consisting of diethanolamine, dipropanolamine and dibutanolamine.
Priority Claims (1)
Number |
Date |
Country |
Kind |
1-80759 |
Mar 1989 |
JPX |
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Parent Case Info
This application is a continuation of application Ser. No. 07/502,066, filed Mar. 29, 1990, abandoned.
US Referenced Citations (4)
Number |
Name |
Date |
Kind |
4407899 |
Hara et al. |
Oct 1983 |
|
4775600 |
Adaniya et al. |
Oct 1988 |
|
4889775 |
Adaniya et al. |
Dec 1989 |
|
4959277 |
Saeki et al. |
Sep 1990 |
|
Foreign Referenced Citations (4)
Number |
Date |
Country |
230320 |
Jul 1987 |
EPX |
62-289274 |
Dec 1987 |
JPX |
63-35798 |
Feb 1988 |
JPX |
1-8033 |
Jan 1989 |
JPX |
Continuations (1)
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Number |
Date |
Country |
Parent |
502066 |
Mar 1990 |
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