Method of producing powder coating material

Patent metadata

Field	Value
Publication number	US-11708496-B2
Application number	US-202016912790-A
Country	US
Kind code	B2
Filing date	Jun 26, 2020
Priority date	Dec 27, 2017
Publication date	Jul 25, 2023
Grant date	Jul 25, 2023

Abstract

The present invention relates to a method of producing a powder coating material containing a fluororesin and a non-fluororesin. The method of producing a powder coating material includes kneading a raw material containing the fluororesin and the non-fluororesin with a kneading extruder equipped with a screw having a kneading zone, wherein a ratio of a length L K of the kneading zone to an effective length L S of the screw (L K /L S ×100) is 21.0 to 50.0%.

First claim

The invention claimed is:

1. A method of producing a powder coating material containing a fluororesin and a non-fluororesin, the method comprising:
kneading a raw material containing the fluororesin and the non-fluororesin with a kneading extruder equipped with at least one screw having a kneading zone,
wherein
a ratio of a length L K of the kneading zone to an effective length L S of the screw (L K /L S ×100) is 21.0 to 50.0%,
a value of a ratio of the effective length L S of the screw to an outer diameter D S of the screw (L S /D S ) is 10 to 30,
the kneading zone includes a neutral zone equipped with at least one neutral kneading segment, and
a ratio of a length L N of the neutral zone to the length L K of the kneading zone (L N /L K ×100) is 30% or more.

2. The method according to claim 1 , wherein the screw is rotated at a rotational speed of 10 to 1,000 rpm.

3. The method according to claim 1 , wherein the neutral kneading segment is equipped with a plurality of kneading discs.

4. The method according to claim 1 , wherein the kneading extruder is a twin-screw extruder or a multi-screw extruder having three or more screws.

5. The method according to claim 1 , wherein the raw material is kneaded at a temperature above either a glass transition temperature of the fluororesin or a glass transition temperature of the non-fluororesin and below a temperature at which curing of the raw material initiates.

6. The method according to claim 1 , wherein the raw material is kneaded at a temperature of 100° C. or above and 300° C. or below.

7. The method according to claim 1 , wherein the non-fluororesin is one or more selected from the group consisting of a polyester resin, an acrylic resin, an epoxy resin, and a polyethylene resin.

8. The method according to claim 1 , wherein the fluororesin contains a fluoropolymer containing units based on a fluoroolefin and units based on monomers not containing a fluorine atom.

9. The method according to claim 1 , wherein
the fluororesin contains a fluoropolymer containing units based on a fluoroolefin and units based on monomers not containing a fluorine atom, and
the units based on monomers not containing a fluorine atom includes units based on monomers having a crosslinkable group.

10. The method according to claim 1 , wherein the fluororesin and non-fluororesin have one of a hydroxyl value and an acid value, or have both.

11. The method according to claim 1 , wherein a content of the fluororesin in the raw material is 5 to 95% by mass.

12. The method according to claim 1 , wherein a mass ratio of the fluororesin and the non-fluororesin in the raw material is 70/30 to 10/90.

13. The method according to claim 1 , wherein the raw material contains a curing agent.

14. The method according to claim 1 , wherein the L N /L K ratio is 60% or more.

15. The method according to claim 1 , wherein the kneading zone further includes a non-neutral zone equipped with at least one non-neutral kneading segment.

16. The method according to claim 15 , wherein the non-neutral kneading segment is equipped with a plurality of discs and is at least one selected from the group consisting of a forward feed type screw and a reverse feed type screw.

17. A method of producing a powder coating material containing a fluororesin and a non-fluororesin, the method comprising: kneading a raw material containing the fluororesin and the non-fluororesin with a kneading extruder equipped with at least one screw having a kneading zone and a metering zone downstream of the kneading zone, wherein the screw is rotated at a rotational speed of 100 to 1,000 rpm, a ratio of a length L K of the kneading zone to an effective length Ls of the screw (LK/Ls×100) is 21.0 to 50.0%, and a value of a ratio of the effective length Ls of the screw to an outer diameter Ds of the screw (Ls/Ds) is 10 to 30.

18. A method of producing a powder coating material containing a fluororesin and a non-fluororesin, the method comprising:
kneading a raw material containing the fluororesin and the non-fluororesin with a kneading extruder equipped with at least one screw having a kneading zone,
wherein
the screw is rotated at a rotational speed of 100 to 1,000 rpm,
a ratio of a length L K of the kneading zone to an effective length L S of the screw (L K /L S ×100) is 21.0 to 50.0%,
the kneading zone includes a neutral zone equipped with at least one neutral kneading segment, and
a ratio of a length L N of the neutral zone to the length L K of the kneading zone (L N /L K ×100) is 30% or more.

Assignees

• Agc Inc

Inventors

• Luo Lei
• Wang Zhehong
• Iruya Ken

Classifications

• C09D5/03 Primary

  Powdery paints · CPC title

• B29B7/42

  with screw or helix · CPC title

• B29B7/421

  with screw and additionally other mixing elements on the same shaft, e.g. paddles, discs, bearings, rotor blades of the Banbury type · CPC title

• B29B7/48

  with intermeshing devices, e.g. screws · CPC title

• B29B7/482

  provided with screw parts in addition to other mixing parts, e.g. paddles, gears, discs · CPC title