US4113580A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Steel sheet useful in forming foodstuff and beverage cans
Assignee: Toyo Kohan Co Ltd
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Filing: 1977-07-21
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Granted: 1978-09-12
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Expires: 1997-07-21
Abstract
Abstract A steel sheet which has been treated to form thereon a first layer of an iron-tin alloy and a second layer of hydrated chromium oxide. This treated steel sheet can be effectively coated with an organic coating, and is useful in forming cans for foodstuffs and carbonated beverages.
Inventors
- 👤 Nobuyuki Tsutsui
- 👤 Tsuneo Inui
- 👤 Hiroaki Kawamura
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 17:06
CPC Classifications
C; C25; C25D; C25D3/00; C25D3/02; C25D3/30; C25D11/00; C25D11/38
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
222 words
A process for producing a steel sheet containing a first layer of an iron-tin alloy and a second layer of hydrated chromium oxide which comprises electrolytically tin plating a substantially clean steel sheet base in an electrolyte containing stannous sulfate, stannous chloride, stannous fluoborate, sodium stannate or potassium stannate, to obtain a tin-plated steel sheet in which the amount of plated tin is 0.05-1.5 g/m 2 , heating said tin-plated steel sheet at a temperature sufficiently above the melting point of tin for a time sufficient to form a first layer containing an iron-tin alloy on the surface of said base, the amount of said iron-tin alloy being 0.05-1.0 g/m 2 , calculated as tin, the amount of any free tin in said first layer being less than one-third of the total amount of said plated tin, and subjecting the resultant steel sheet to an electrolytic treatment at 5-20 coulombs/dm 2 in an electrolyte containing chromic acid and at least one additive selected from the group consisting of sulfuric acid, a fluorine compound, an aromatic disulfonic acid and thiourea, to form a second layer consisting essentially of hydrated chromium oxide in an amount of 0.005-0.05 g/m 2 , calculated as chromium, any metallic chromium deposited between said first and second layers being present in an amount less than 0.005 g/m 2 .
Claim 2
Dependent Claim
222 words
A process for producing a steel sheet containing a first layer of an iron-tin alloy and a second layer of hydrated chromium oxide which comprises electrolytically tin plating a substantially clean steel sheet base in an electrolyte containing stannous sulfate, stannous chloride, stannous fluoborate, sodium stannate or potassium stannate, to obtain a tin-plated steel sheet in which the amount of plated tin is 0.05-1.5 g/m 2 , heating said tin-plated steel sheet at a temperature sufficiently above the melting point of tin for a time sufficient to form a first layer containing an iron-tin alloy on the surface of said base, the amount of said iron-tin alloy being 0.05-1.0 g/m 2 , calculated as tin, the amount of any free tin in said first layer being less than one-third of the total amount of said plated tin, and subjecting the resultant steel sheet to an electrolytic treatment at 5-20 coulombs/dm 2 in an electrolyte containing chromic acid and at least one additive selected from the group consisting of sulfuric acid, a fluorine compound, an aromatic disulfonic acid and thiourea, to form a second layer consisting essentially of hydrated chromium oxide in an amount of 0.005-0.05 g/m 2 , calculated as chromium, any metallic chromium deposited between said first and second layers being present in an amount less than 0.005 g/m 2 .
Claim 3
Dependent Claim
65 words
A process according to claim 1, wherein electrolytic tin plating is carried out in an acidic electrolyte at a temperature of 30°-60° C and a current density of 5-50 A/dm 2 , the concentration of stannous ions in the electrolyte being 1.5-20 g/l, the concentration of acid in the electrolyte being 1.0-15 g/l, the weight ratio of said stannous ions to said acid being 1-3:1.
Claim 4
Dependent Claim
53 words
A process according to claim 1, wherein electrolytic tin plating is carried out in an alkaline electrolyte at a temperature of 70°-90° C and a current density of 1-10 A/dm 2 , the concentration of stannic ions in the electrolyte being 30-70 g/l, the concentration of base in the electrolyte being 10-25 g/l.
Claim 5
Dependent Claim
24 words
A process according to claim 1, wherein heating said tin-plated steel sheet is carried out at a temperature of 232°-400° C for 0.5-10 seconds.
Claim 6
Dependent Claim
55 words
A process according to claim 1, wherein electrolytic treatment to form said second layer is carried out at a temperature of 35°-70° C and a current density of 5-50 A/dm 2 for 0.1-5 seconds in an electrolyte containing 30-100 g/l of chromic acid, the weight ratio of said chromic acid to said additive being 100-300:1.
Claim 7
Dependent Claim
80 words
A process according to claim 1, wherein said fluorine compound is selected from the group consisting of HF, NaF, KF, NH 4 F, H 2 SiF 6 , NaSiF 6 , KSiF 6 , NH 4 SiF 6 , HBF 4 , NaBF 4 , KBF 4 , NH 4 BF 4 , NaHF 2 , KHF 2 and NH 4 HF 2 and said aromatic disulfonic acid is selected from the group consisting of 2,4-disulfophenol, 3,5-disulfocatechol, 3,6-disulfonaphth-2-ol and 3,6-disulfo-1,8-dihydroxynaphthalene.
Claim 8
Dependent Claim
137 words
A process for producing a steel sheet containing a first layer of an iron-tin alloy and a second layer of hydrated chromium oxide which comprises electrolytically tin plating a substantially clean steel sheet base in an electrolyte containing stannous sulfate, stannous chloride, stannous fluoborate, sodium stannate or potassium stannate, to obtain a tin-plated steel sheet in which the amount of plated tin is 0.05-1.5 g/m 2 , heating said tin-plated steel at a temperature sufficiently above the melting point of tin for a time sufficient to form a first layer containing an iron-tin alloy on the surface of said base, the amount of said iron-tin alloy being 0.05-1.0 g/m 2 , calculated as tin, the amount of any free tin in said first layer being less than one-third of the total amount of said plated tin, and
Claim 9
Dependent Claim
137 words
A process for producing a steel sheet containing a first layer of an iron-tin alloy and a second layer of hydrated chromium oxide which comprises electrolytically tin plating a substantially clean steel sheet base in an electrolyte containing stannous sulfate, stannous chloride, stannous fluoborate, sodium stannate or potassium stannate, to obtain a tin-plated steel sheet in which the amount of plated tin is 0.05-1.5 g/m 2 , heating said tin-plated steel at a temperature sufficiently above the melting point of tin for a time sufficient to form a first layer containing an iron-tin alloy on the surface of said base, the amount of said iron-tin alloy being 0.05-1.0 g/m 2 , calculated as tin, the amount of any free tin in said first layer being less than one-third of the total amount of said plated tin, and
Claim 10
Dependent Claim
62 words
subjecting the resultant steel sheet to an electrolytic treatment at 8-140 coulombs/dm 2 in an electrolyte containing sodium dichromate, to form a second layer consisting essentially of hydrated chromium oxide in an amount of 0.005-0.05 g/m 2 , calculated as chromium any metallic chromium deposited between said first and second layers being present in an amount less than 0.005 g/m 2 .
Claim 11
Dependent Claim
62 words
subjecting the resultant steel sheet to an electrolytic treatment at 8-140 coulombs/dm 2 in an electrolyte containing sodium dichromate, to form a second layer consisting essentially of hydrated chromium oxide in an amount of 0.005-0.05 g/m 2 , calculated as chromium any metallic chromium deposited between said first and second layers being present in an amount less than 0.005 g/m 2 .
Claim 12
Dependent Claim
65 words
A process according to claim 7, wherein electrolytic tin plating is carried out in an acidic electrolyte at a temperature of 30°-60° C and a current density of 5-50 A/dm 2 , the concentration of stannous ions in the electrolyte being 1.5-20 g/l, the concentration of acid in the electrolyte being 1.0-15 g/l, the weight ratio of said stannous ions to said acid being 1-3:1.
Claim 13
Dependent Claim
53 words
A process according to claim 7, wherein electrolytic tin plating is carried out in an alkaline electrolyte at a temperature of 70°-90° C and a current density of 1-10 A/dm 2 , the concentration of stannic ions in the electrolyte being 30-70 g/l, the concentration of base in the electrolyte being 10-25 g/l.
Claim 14
Dependent Claim
24 words
A process according to claim 7, wherein heating said tin-plated steel sheet is carried out at a temperature of 232°-400° C for 0.5-10 seconds.
Claim 15
Dependent Claim
48 words
A process according to claim 7, wherein electrolytic treatment to form said second layer is carried out at a temperature of 35°-70° C and a current density of 8-40 A/dm 2 for 0.1-10 seconds in an electrolyte having a pH of 3.5-7.0 containing 20-60 g/l of sodium dichromate.
References Cited (Backward Citations)
US2974091A
Cited
US3890164A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1981-09-11 | 1982-03-13 | 1982-09-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-09-11 | 1986-03-13 | 1986-09-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-09-11 | 1990-03-13 | 1990-09-12 | $7700.00 | Window Closed / Lapsed |