POWDER COATING METHOD

• US 20120237775A1
• Filed: 01/17/2012
• Published: 09/20/2012
• Est. Priority Date: 03/18/2011
• Status: Active Grant

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: KOSUGI, Naofumi, Yui, Yasushi
• Granted Patent: US 8,889,231 B2
• Time in Patent Office: Days
• US Class Current: 428/418
• CPC Class Codes: B05D 1/06 Applying particulate materials
• CPC Class Codes: B05D 2202/00 Metallic substrate
• CPC Class Codes: C09D 5/032 characterised by a special effect of the produced film, e.g. wrinkle, pearlescence, matt finish
• CPC Class Codes: Y10T 428/31529 Next to metal

Abstract

A coating film is formed on a surface of a coating object by adhering a coating powder to the coating object by spraying the coating powder from an electrostatic gun together with a compressed gas. A voltage not smaller than 80 kV but not larger than 100 kV is applied between the electrostatic gun and the coating object. Moreover, a current flowed between the electrostatic gun and the coating object is set to be not smaller than 10 μA but not larger than 20 μA. Further, a pressure of the compressed gas for spraying the coating powder is set to be not smaller than 3 kgf/cm² but not larger than 6 kgf/cm².

Claims

1. A powder coating method comprising:

adhering a coating powder to a coating object by spraying the coating powder from an electrostatic gun together with a compressed gas,

wherein, in the adhering the coating powder to the coating object, the coating powder is sprayed from the electrostatic gun under conditions that a voltage applied between the electrostatic gun and the coating object is set to be not smaller than 80 kV but not larger than 100 kV, a current flowed between the electrostatic gun and the coating object is set to be not smaller than 10 μ

A but not larger than 20 μ

A, and a pressure for spraying the coating powder from the electrostatic gun is set to be not smaller than 3 kgf/cm² but not larger than 6 kgf/cm².

2. The powder coating method according to claim 1, further comprising:

forming a coating film on a surface of the coating object by subjecting the coating object with the coating powder adhered thereto to a heat treatment,

wherein, in the forming the coating film on the surface of the coating object, the coating object is subjected to the heat treatment at a temperature not lower than 180°

C. but not higher than 220°

C.

3. The powder coating method according to claim 1, wherein, in the adhering the coating powder to the coating object, in a graph taking applied voltage on a horizontal axis and current on a vertical axis, the voltage applied between the electrostatic gun and the coating object and the current flowed between the electrostatic gun and the coating object are set to satisfy conditions on a line segment connecting a point having 80 kV on the horizontal axis and 10 μ

A on the vertical axis and a point having 100 kV on the horizontal axis and 20 μ

A on the vertical axis.

4. The powder coating method according to claim 1, wherein a thickness of the coating film is not smaller than 40 μ

m but not larger than 70 μ

m.

5. A chassis comprising:

a coating film formed by

adhering a coating power to a coating object by spraying the coating powder from an electrostatic gun configured to spray the coating powder under conditions that a voltage applied between the electrostatic gun and the coating object is set to be not smaller than 80 kV but not larger than 100 kV, a current flowed between the electrostatic gun and the coating object is set to be not smaller than 10 μ

A but not larger than 20 μ

A, and a pressure for spraying the coating powder from the electrostatic gun is set to be not smaller than 3 kgf/cm² but not larger than 6 kgf/cm², and

subjecting the coating object with the coating powder adhered thereto to a heat treatment at a temperature not lower than 180°

C. but not higher than 220°

C.