Patent EP0423740A2 successfully refreshed from Google Patents.
EP0423740A2
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EP
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Organic composite coated steel strip having improved corrosion resistance and weldability
Assignee: JFE Steel Corp
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Filing: 1990-10-16
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Granted: —
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Expires: 2010-10-16
Abstract
Abstract Organic composite coated steel strips having improved corrosion resistance, weldability and coating adherence are obtained when an organic composite layer is applied to a chromate layer on a zinc or zinc base alloy plated steel substrate. The chromate layer containing up to 70% of Cr⁶⁺ based on the total chromium weight is coated in a weight of 5 to 500 mg/m² of Cr. The organic composite layer is formed to a dry weight of 0.2 to 3.0 g/m² from a coating composition comprising (A) a silica sol having silica dispersed in an organic solvent with a water content of up to 3.0%, the silica having an organic deposit on its surface in an amount of up to 5.0% of C based on the total silica weight, the silica having an average particle size of 0.05 to 3.0 µm and a specific surface area of 50 to 800 m²/g, and (B) an organic resin binder having a number average molecular weight of at least 2,000. The coated strips are suitable for use as automobile bodies by press forming.
Inventors
- 👤 Kenji C/O Technical Research Div. Takao
- 👤 Hideo C/O Technical Research Div. Ohgishi
- 👤 Hajime C/O Technical Research Div. Kimura
- 👤 Shuichi C/O Technical Research Div. Sakaguchi
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-04 14:00
CPC Classifications
C; C25; C25D; C25D5/00; C25D5/10; B; B05; B05D; B05D7/00; B05D7/50; B05D7/51; C09; C09D; C09D5/00; C09D5/08; C23; C23C; C23C22/00; C23C22/82; C23C22/83; C23C28/00; C23C28/30; C23C28/32; C23C28/322; C23C28/3225; C23C28/34; C23C28/345; B05D2202/00; B05D2202/10; B05D2350/00; B05D2350/20; B05D2701/00; B05D2701/40; Y; Y10; Y10T; Y10T428/00; Y10T428/12; Y10T428/12493; Y10T428/12535; Y10T428/12556; Y10T428/12569; Y10T428/12611; Y10T428/12771; Y10T428/12785; Y10T428/12792; Y10T428/12799
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
143 words
An organic composite coated steel strip having improved corrosion resistance and weldability, comprising a zinc or zinc base alloy plated steel substrate, a chromate layer on the substrate containing up to 70 % by weight of Cr⁶⁺ based on the total chromium quantity, said chromate layer being coated in a weight of 5 to 500 mg/m² of elemental chromium, and an organic composite layer coated on said chromate layer from a coating composition comprising (A) a silica and (B) an organic resin composition having a number average molecular weight of at least 2,000 such that (a) the silica primary particles agglomerate into secondary particles, (b) the number of the secondary particles ranges from 1x10⁴ to 1x10⁹ per square millimeter of a cross section of said organic composite layer, and (c) said organic composite layer has a dry weight of 0.2 to 3.0 g/m².
Claim 2
Dependent Claim
143 words
An organic composite coated steel strip having improved corrosion resistance and weldability, comprising a zinc or zinc base alloy plated steel substrate, a chromate layer on the substrate containing up to 70 % by weight of Cr⁶⁺ based on the total chromium quantity, said chromate layer being coated in a weight of 5 to 500 mg/m² of elemental chromium, and an organic composite layer coated on said chromate layer from a coating composition comprising (A) a silica and (B) an organic resin composition having a number average molecular weight of at least 2,000 such that (a) the silica primary particles agglomerate into secondary particles, (b) the number of the secondary particles ranges from 1x10⁴ to 1x10⁹ per square millimeter of a cross section of said organic composite layer, and (c) said organic composite layer has a dry weight of 0.2 to 3.0 g/m².
Claim 3
Dependent Claim
29 words
The steel strip of claim 1 wherein organic resin composition (B) is based on an epichlorohydrin-bisphenol A epoxy resin having a number average molecular weight of at least 2,000.
Claim 4
Dependent Claim
46 words
The steel strip of claim 1 wherein said coating composition contains silica (A) and organic resin composition (B) in such amounts that 10 to 100 parts by weight of silica is present per 100 parts by weight of the resin composition on a dry weight basis.
Claim 5
Dependent Claim
19 words
The steel strip of claim 1 wherein organic resin composition (B) has a hydroxyl number of at least 50.
Claim 6
Dependent Claim
23 words
The steel strip of claim 1 wherein said chromate layer is coated in a weight of 10 to 150 mg/m² of elemental chromium.
Claim 7
Dependent Claim
167 words
An organic composite coated steel strip having improved corrosion resistance and weldability, comprising a zinc or zinc base alloy plated steel substrate, a chromate layer on the substrate containing up to 70% by weight of Cr⁶⁺ based on the total chromium quantity, said chromate layer being coated in a weight of 5 to 500 mg/m² of elemental chromium, and an organic composite layer coated on said chromate layer from a coating composition comprising (A) a silica sol having silica dispersed in an organic solvent with a water content of up to 3 0% by weight, the silica having an organic deposit on its surface in an amount of up to 5.0% by weight, calculated as C, based on the total weight of the silica, the silica having a specific surface area of 50 to 800 m²/g, and (B) an organic resin composition having a number average molecular weight of at least 2,000, said organic composite layer being coated in a dry weight of 0.2 to 3.0 g/m².
Claim 8
Dependent Claim
167 words
An organic composite coated steel strip having improved corrosion resistance and weldability, comprising a zinc or zinc base alloy plated steel substrate, a chromate layer on the substrate containing up to 70% by weight of Cr⁶⁺ based on the total chromium quantity, said chromate layer being coated in a weight of 5 to 500 mg/m² of elemental chromium, and an organic composite layer coated on said chromate layer from a coating composition comprising (A) a silica sol having silica dispersed in an organic solvent with a water content of up to 3 0% by weight, the silica having an organic deposit on its surface in an amount of up to 5.0% by weight, calculated as C, based on the total weight of the silica, the silica having a specific surface area of 50 to 800 m²/g, and (B) an organic resin composition having a number average molecular weight of at least 2,000, said organic composite layer being coated in a dry weight of 0.2 to 3.0 g/m².
Claim 9
Dependent Claim
19 words
The steel strip of claim 6 wherein said silica has an average particle size of 0.05 to 3.0 µm.
Claim 10
Dependent Claim
26 words
The steel strip of claim 6 wherein the organic solvent of silica sol (A) has a total alkali metal content of up to 0.01% by weight.
Claim 11
Dependent Claim
41 words
The steel strip of claim 6 wherein the silica of silica sol (A) has Al³⁺ adhered to the surface of silica in an amount of 0.1 to 20.0% by weight of elemental Al based on the total weight of the silica.
Claim 12
Dependent Claim
29 words
The steel strip of claim 6 wherein organic resin composition (B) is based on an epichlorohydrin-bisphenol A epoxy resin having a number average molecular weight of at least 2,000.
Claim 13
Dependent Claim
48 words
The steel strip of claim 6 wherein said coating composition contains silica sol (A) and organic resin composition (B) in such amounts that 10 to 100 parts by weight of silica sol is present per 100 parts by weight of the resin composition on a dry weight basis.
Claim 14
Dependent Claim
19 words
The steel strip of claim 6 wherein organic resin composition (B) has a hydroxyl number of at least 50.
Claim 15
Dependent Claim
23 words
The steel strip of claim 6 wherein said chromate layer is coated in a weight of 10 to 150 mg/m² of elemental chromium.
Claim 16
Dependent Claim
23 words
The steel strip of claim 6 wherein the silica of silica sol (A) has a specific surface area of 100 to 400 m²/g.
Claim 17
Dependent Claim
26 words
The steel strip of claim 6 wherein said organic composite layer is coated by baking the coating composition at the maximum temperature of 100 to 200°C.
Claim 18
Dependent Claim
38 words
The steel strip of claim 6 wherein the organic solvent of silica sol (A) is selected from the group consisting of n-butanol, isobutanol, ethyl cellosolve, butyl cellosolve, xylene, ethylene glycol, ethylene glycol n-propyl ether, dimethylacetamide, and mixtures thereof.
References Cited (Backward Citations)
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