Painted metal plate and method for producing same

Patent metadata

Field	Value
Publication number	US-12110409-B2
Application number	US-201917282019-A
Country	US
Kind code	B2
Filing date	Apr 10, 2019
Priority date	Oct 3, 2018
Publication date	Oct 8, 2024
Grant date	Oct 8, 2024

Abstract

The present invention addresses the problem of providing a painted metal plate having rain-streak-stain resistance and a good appearance, and a method for producing the same. To solve this problem, the method for producing a painted metal plate includes a step for forming a coating by applying a paint containing a silicone resin and a fluorine-containing resin to the surface of a metal plate and curing the paint, and a step for performing flame treatment on the coating. The silicone resin contains 5 to 50 mol % of a silanol group with respect to the total molar mass of Si atoms.

First claim

The invention claimed is:

1. A coated metal sheet, comprising: a metal sheet; and a fluorinated coating film formed on the metal sheet, wherein
the coating film contains a cured product of a silicone resin, and a fluorine-containing resin;
an amount of the cured product of the silicone resin is 1 to 10 parts by mass of a total mass of the coating film;
the silicone resin contains Si atoms derived from trialkoxysilane in an amount of 50 to 100 mol % relative to the total number of moles of Si atoms;
a weight average molecular weight of the silicone resin is 1000 to 10000;
when a surface of the coating film is analyzed with X-ray electron spectroscopy using an A1Kα ray as an X-ray source, Si a and x satisfy the following expressions respectively, wherein Si a is a proportion of Si atoms based on a total amount of Si atoms, F atoms, C atoms, and O atoms, and x is a ratio of an amount of O atoms to an amount of C atoms:
Si a ≥8 atm %

x≥0.8; and

when a C1s peak top in an X-ray photoelectron spectroscopic spectrum obtained through the analysis with X-ray electron spectroscopy is corrected to be 285 eV and a Si 2p spectrum is separated into a peak corresponding to 103.5 eV and a peak corresponding to 102.7 eV, y satisfies the following expression, wherein y is a ratio of a peak area of 103.5 eV to a peak area of the entire Si 2p spectrum:
y≥0.6.

2. The coated metal sheet according to claim 1 , wherein a methylene iodide sliding angle on the surface of the coating film is 15° or more and 50° or less.

3. The coated metal sheet according to claim 1 , wherein the cured product of a silicone resin comprises a structure derived from methyltrialkoxysilane or phenyltrialkoxysilane.

4. The coated metal sheet according to claim 1 , wherein the metal sheet is a zinc-based plated steel sheet.

5. A method for producing the coated metal sheet according to claim 1 , comprising:
forming a coating film on a surface of a metal sheet by applying and curing a coating material containing a silicone resin and a fluorine-containing resin; and
subjecting the coating film to a flame treatment,
wherein the silicone resin contains silanol groups in an amount of 5 to 50 mol % relative to a total number of moles of Si atoms.

6. The method for producing a coated metal sheet according to claim 5 , wherein the silicone resin contains Si atoms derived from trialkoxysilane in an amount of 50 to 100 mol % relative to the total number of moles of Si atoms.

7. The method for producing a coated metal sheet according to claim 5 , wherein a proportion of a number of moles of aryl groups directly bonded to Si atoms based on a number of moles of alkyl groups directly bonded to Si atoms is 20 to 80% in the silicone resin.

Assignees

• Nippon Steel Corp

Inventors

• Takiguchi Keiko
• Satou Masaki
• Suzuki Seiju
• Sugita Shuichi

Classifications

• C23C2/26

  After-treatment (C23C2/14 takes precedence) · CPC title

• C23C26/00

  Coating not provided for in groups C23C2/00 - C23C24/00 · CPC title

• B05D7/14

  to metal, e.g. car bodies (involving a chemical reaction between the metal and the coating C23) · CPC title

• B05D3/08 Primary

  by flames · CPC title

• C09D183/04

  Polysiloxanes · CPC title