SURFACE-TREATED METAL SHEET AND ORGANIC RESIN-COVERED SURFACE-TREATED METAL SHEET

• US 20180291232A1
• Filed: 05/18/2016
• Published: 10/11/2018
• Est. Priority Date: 05/21/2015
• Status: Active Grant

• Current Assignee: Toyo Seikan Group Holdings, Ltd.
• Original Assignee: Toyo Seikan Group Holdings, Ltd.
• Inventors: KASHIWAKURA, Takuya, FUNAGI, Yuji, MIYAI, Tomohiro, SAKURAGI, Arata
• Granted Patent: US 10,457,832 B2
• Time in Patent Office: Days
• CPC Class Codes: B05D 1/40 Distributing applied liquids or other fluent materials by members moving relatively to surface
• CPC Class Codes: B05D 3/0272 with ovens
• CPC Class Codes: B05D 7/14 to metal, e.g. car bodies involving a chemical reaction between the metal and the coating C23
• CPC Class Codes: B05D 7/544 the first layer is let to dry at least partially before applying the second layer
• CPC Class Codes: B32B 15/08 of synthetic resin
• CPC Class Codes: B32B 15/09 comprising polyesters
• CPC Class Codes: B32B 15/20 comprising aluminium or copper B32B15/016 and B32B15/017 take precedence
• CPC Class Codes: B32B 2255/06 on metal layer
• CPC Class Codes: B32B 2255/26 Polymeric coating
• CPC Class Codes: B32B 2439/66 Cans, tins
• CPC Class Codes: B65D 1/00 Containers having bodies formed in one piece, e.g. by casting metallic material, by moulding plastics, by blowing vitreous material, by throwing ceramic material, by moulding pulped fibrous material, by deep-drawing operations performed on sheet material by winding, bending, or folding paper B65D3/00, B65D5/00; specially constructed to be opened by cutting, piercing, or tearing of wall portions B65D17/00; pallets B65D19/00; details of bottles or of jars B65D23/00; bundles of articles held together by packaging elements for convenience of storage or transport, e.g. portable segregating carriers for plural receptacles such as beer cans, pop bottles, B65D71/00
• CPC Class Codes: B65D 1/12 Cans, casks, barrels, or drums
• CPC Class Codes: B65D 17/02 of curved cross-section, e.g. cans of circular or elliptical cross-section
• CPC Class Codes: C09D 167/02 Polyesters derived from dicarboxylic acids and dihydroxy compounds C09D167/06 takes precedence
• CPC Class Codes: C09D 7/61 inorganic
• CPC Class Codes: C23C 22/08 Orthophosphates
• CPC Class Codes: C23C 22/48 not containing phosphates, hexavalent chromium compounds, fluorides or complex fluorides, molybdates, tungstates, vanadates or oxalates
• CPC Class Codes: C23C 22/50 Treatment of iron or alloys based thereon
• CPC Class Codes: C23C 22/56 Treatment of aluminium or alloys based thereon
• CPC Class Codes: C23C 28/00 Coating for obtaining at least two superposed coatings either by methods not provided for in a single one of groups C23C2/00 - C23C26/00 or by combinations of methods provided for in subclasses C23C and C25C or C25D

Abstract

A chromium-free surface-treated metal sheet includes a metal sheet, a surface-treatment coating that contains a polycarboxylic acid type polymer and a zirconium compound and that is formed on at least one surface of the metal sheet, and a coating that contains a polyester resin, a phenol resin and an acid catalyst and that is formed on the surface-treatment coating. The surface-treated metal sheet can be used for producing cans and can lids maintaining excellent dent resistance even for acidic beverages, without permitting the organic resin film formed on the coating to be peeled even under high-temperature and wet environments during a sterilization treatment or the like, and maintaining excellent hot water-resistant adhering property.

Claims

1. A surface-treated metal sheet comprising a metal sheet, a surface-treatment coating that contains a polycarboxylic acid type polymer and a zirconium compound and that is formed on at least one surface of said metal sheet, and a coating that contains a polyester resin, a phenol resin and an acid catalyst and that is formed on said surface-treatment coating.

2. The surface-treated metal sheet according to claim 1, wherein when said surface-treatment coating is measured for its infrared absorption spectra, a peak height ratio (β

/α

) of a maximum absorption peak height (α

) in a wave number range of 1660 to 1760 cm<sup>−

1</sup> and a maximum absorption peak height (β

) in a wave number range of 1490 to 1659 cm<sup>−

1</sup> is from 0.20 to 2.54.

3. The surface-treated metal sheet according to claim 1, wherein said polycarboxylic acid type polymer is a polymer or a copolymer obtained by polymerization of at least one kind of polymerizable monomer selected from acrylic acid, methacrylic acid, itaconic acid and maleic acid, or is a mixture thereof.

4. The surface-treated metal sheet according to claim 1, wherein said zirconium compound is a zirconium compound derived from an oxyzirconium salt.

5. The surface-treated metal sheet according to claim 1, wherein in said surface-treatment coating, the content of said polycarboxylic acid type polymer is 10 to 100 mg/m² calculated as carbon and the content of said zirconium compound is 2 to 80 mg/m² calculated as zirconium.

6. The surface-treated metal sheet according to claim 1, wherein said polyester resin has a glass transition temperature (Tg) of 15°

C. to 80°

C.

7. The surface-treated metal sheet according to claim 1, wherein said polyester resin contains an aromatic dicarboxylic acid and an aliphatic dicarboxylic acid having 6 to 14 carbon atoms as the dicarboxylic acid components for constituting the polyester resin, the molar ratio of the aromatic dicarboxylic acid and the aliphatic dicarboxylic acid having 6 to 14 carbon atoms being 95:

5 to 80;

20.

8. The surface-treated metal sheet according to claim 1, wherein said phenol resin is the one in which a methylol group of the phenol resin derived from the m-cresol is alkoxymethylated with an n-butanol.

9. The surface-treated metal sheet according to claim 1, wherein said phenol resin is contained in an amount in a range of 5 to 50 parts by mass per 100 parts by mass of said polyester resin.

10. The surface-treated metal sheet according to claim 1, wherein said coating is formed by using an aqueous coating composition that contains a water-soluble and/or a water-dispersible polyester resin, a phenol resin, an acid catalyst and an aqueous medium.

11. An organic resin-covered surface-treated metal sheet obtained by forming an organic resin film on the coating formed on the surface-treatment coating of the surface-treated metal sheet described in claim 1.

12. The organic resin-covered surface-treated metal sheet according to claim 11, wherein said organic resin film is a polyester resin film.

13. A can body made from the organic resin-covered surface-treated metal sheet of claim 11.

14. A can lid made from the surface-treated metal sheet described in claim 1.

15. A can lid made from the organic resin-covered surface-treated metal sheet of claim 11.