Fluidized-bed coating method and fluidized-bed coating apparatus

Patent metadata

Field	Value
Publication number	US-2021299699-A1
Application number	US-202016932855-A
Country	US
Kind code	A1
Filing date	Jul 20, 2020
Priority date	Mar 27, 2020
Publication date	Sep 30, 2021
Grant date	—

Abstract

A fluidized-bed coating method includes: immersing at least part of a workpiece in a powder coating material contained in a fluidized-bed vessel while air is introduced from a bottom of the fluidized-bed vessel at an average air flow rate of 5 mm/min or higher and 20 mm/min or lower per unit area of the bottom so that a floating ratio of the powder coating material is 5% or higher and 20% or lower, the workpiece having a temperature higher than or equal to a softening temperature of the powder coating material and lower than or equal to a melting temperature of the powder coating material; taking the workpiece out of the powder coating material; and heating the powder coating material attached to the workpiece.

First claim

What is claimed is:

1 . A fluidized-bed coating method comprising:
immersing at least part of a workpiece in a powder coating material contained in a fluidized-bed vessel while air is introduced from a bottom of the fluidized-bed vessel at an average air flow rate of 5 mm/min or higher and 20 mm/min or lower per unit area of the bottom so that a floating ratio of the powder coating material is 5% or higher and 20% or lower, the workpiece having a temperature higher than or equal to a softening temperature of the powder coating material and lower than or equal to a melting temperature of the powder coating material; taking the workpiece out of the powder coating material; and heating the powder coating material attached to the workpiece.

2 . The fluidized-bed coating method according to claim 1 , wherein the workpiece is preheated at a temperature in a range of from a temperature 20° C. higher than the softening temperature of the powder coating material to a temperature 5° C. higher than the melting temperature of the powder coating material and then immersed in the powder coating material.

3 . The fluidized-bed coating method according to claim 1 , wherein the powder coating material has a volume average particle diameter D50v of 5 μm or more and 20 μm or less, and
the powder coating material has an aerated flowability energy AE of 5 mJ or higher and lower than 100 mJ, where the AE is measured with a powder rheometer using a vessel having a cross-sectional area with ø 50 mm under conditions of a rotary blade tip speed of 100 mm/sec, a rotary blade helix angle of −5°, and an air flow rate of 20 ml/min.

4 . The fluidized-bed coating method according to claim 1 , wherein the powder coating material has a volume particle size distribution index GSDv of 1.15 or higher and 1.40 or lower.

5 . The fluidized-bed coating method according to claim 4 , wherein the powder coating material has a volume particle size distribution index GSDv of 1.15 or higher and 1.25 or lower.

6 . The fluidized-bed coating method according to claim 1 , wherein the floating ratio is 10% or higher and 20% or lower.

7 . The fluidized-bed coating method according to claim 1 , wherein the powder coating material includes powder particles and an external additive on the powder particles.

8 . The fluidized-bed coating method according to claim 7 , wherein the external additive is a hydrophobic external additive.

9 . The fluidized-bed coating method according to claim 7 , wherein the external additive has a volume average particle diameter of 5 nm or more and 30 nm or less.

10 . A fluidized-bed coating apparatus comprising:
a fluidized-bed vessel that contains a powder coating material and has a bottom from which air is introduced at an average air flow rate of 5 mm/min or higher and 20 mm/min or lower per unit area of the bottom; an immersing unit that immerses at least part of a workpiece in the powder coating material while a floating ratio of the powder coating material in the fluidized-bed vessel is 5% or higher and 20% or lower, the workpiece having a temperature higher than or equal to a softening temperature of the powder coating material and lower than or equal to a melting temperature of the powder coating material; a taking-out unit that takes the workpiece out of the powder coating material; and a heating unit that heats the powder coating material attached to the workpiece.

11 . The fluidized-bed coating apparatus according to claim 10 , further comprising:
a preheating unit that preheats the workpiece at a temperature in a range of from a temperature 20° C. higher than the softening temperature of the powder coating material to a temperature 5° C. higher than the melting temperature of the powder coating material, wherein the immersing unit immerses, in the powder coating material, the workpiece preheated by the preheating unit.

12 . The fluidized-bed coating apparatus according to claim 10 , wherein the powder coating material has a volume average particle diameter D50v of 5 μm or more and 20 μm or less, and
the powder coating material has an aerated flowability energy AE of 5 mJ or higher and lower than 100 mJ, where the AE is measured with a powder rheometer using a vessel having a cross-sectional area with ø 50 mm under conditions of a rotary blade tip speed of 100 mm/sec, a rotary blade helix angle of −5°, and an air flow rate of 20 ml/min.

13 . The fluidized-bed coating apparatus according to claim 10 , wherein the powder coating material has a volume particle size distribution index GSDv of 1.15 or higher and 1.40 or lower.

14 . The fluidized-bed coating apparatus according to claim 13 , wherein the powder coating material has a volume particle size distribution index GSDv of 1.15 or higher and 1.25 or lower.

15 . The fluidized-bed coating apparatus according to claim 10 , wherein the floating ratio is 10% or higher and 20% or lower.

16 . The fluidized-bed coating apparatus according to claim 10 , wherein the powder coating material includes powder particles and an external additive on the powder particles.

17 . The fluidized-bed coating apparatus according to claim 16 , wherein the external additive is a hydrophobic external additive.

18 . The fluidized-bed coating apparatus according to claim 16 , wherein the external additive has a volume average particle diameter of 5 nm or more and 30 nm or less.

Assignees

• Fujifilm Business Innovation Corp

Inventors

• Furuki Makoto
• Yoshino Susumu
• Saegusa Hiroshi
• Yoshida Satoshi

Classifications

• C09D133/068

  containing glycidyl groups · CPC title

• C08K2003/164

  Aluminum halide, e.g. aluminium chloride · CPC title

• B05C19/06

  Storage, supply or control of the application of particulate material; Recovery of excess particulate material · CPC title

• B05C19/02 Primary

  using fluidised-bed techniques (fluidised-bed technique in general B01J8/24) · CPC title

• C09D167/00

  Coating compositions based on polyesters obtained by reactions forming a carboxylic ester link in the main chain (based on polyester-amides C09D177/12; based on polyester-imides C09D179/08); Coating compositions based on derivatives of such polymers · CPC title