Powder paints, method for production and use thereof

• US 20040082715A1
• Filed: 10/24/2003
• Published: 04/29/2004
• Est. Priority Date: 06/01/2001
• Status: Active Grant

• Current Assignee: BASF Coatings AG (BASF SE)
• Original Assignee: BASF Coatings AG (BASF SE)
• Inventors: Polke, Reinhard, Bayer, Robert, Wolf, Heiko, Stang, Michael, Jung, Werner-Alfons, Mauss, Michael, Berg, Jan, Weintz, Hans-Joachim
• Granted Patent: US 7,449,516 B2
• Time in Patent Office: Days
• US Class Current: 525/50
• CPC Class Codes: C08J 3/16 by coagulating dispersions C08J3/122 takes precedence
• CPC Class Codes: C09D 5/03 Powdery paints

Abstract

Powder coating materials preparable by

(1) mixing at least two liquid components comprising in each case at least one liquid starting product in a static mixer, to give a molecularly disperse and/or finely dispersed liquid mixture,

(2) emulsifying the liquid mixture (1) in an aqueous medium in a dispersing unit, to give an aqueous emulsion of liquid particles,

(3) cooling the emulsion (2) so that a suspension of dimensionally stable particles is formed,

(4) isolating the dimensionally stable particles from the suspension (3)

or alternatively

(3) isolating the dimensionally stable particles directly from the emulsion (2);

and also processes for preparing them and their use as coating materials, adhesives, and sealing compounds or to prepare such compositions.

Claims

1. A powder coating material preparable by

(1) mixing at least two liquid components comprising in each case at least one liquid starting product in a static mixer, to give a molecularly disperse and/or finely dispersed liquid mixture,

(2) emulsifying the liquid mixture (1) in an aqueous medium in a dispersing unit, to give an aqueous emulsion of liquid particles,

(3) cooling the emulsion (2) so that a suspension of dimensionally stable particles is formed, and

(4) isolating the dimensionally stable particles from the suspension (3)

or alternatively

(3) isolating the dimensionally stable particles directly from the emulsion (2).

2. The powder coating material as claimed in claim 1, wherein at least one of the liquid components is a melt.

3. The powder coating material as claimed in claim 1 or 2, wherein at least one of the liquid components comprises or consists of a binder melt.

4. The powder coating material as claimed in any of claims 1 to 3, wherein at least one of the melts comprises or consists of a crosslinking agent melt.

5. The powder coating material as claimed in any of claims 1 to 4, wherein at least one of the liquid components comprises liquid or solid additives.

6. The powder coating material as claimed in any of claims 1 to 5, wherein the residence time of the melts in the static mixer is from 0.5 to 20 seconds.

7. The powder coating material as claimed in any of claims 1 to 6, wherein an inline dissolver is used as dispersing unit.

8. The powder coating material as claimed in claim 7, wherein the inline dissolver is a toothed-ring dispersing unit comprising at least one cylindrical arrangement of at least two comminutor rings (stator and rotor) which are seated on holders, are in mutual embrace, and are rotatable in opposite directions relative to one another, the working gap produced by the relative movement between stator and rotor having walls which extend nonparallelwise with respect to one another.

9. The powder coating material as claimed in any of claims 1 to 8, wherein the residence time of the liquid mixture (1) and of the aqueous medium in the dispersing unit is from 0.5 to 20 seconds.

10. The powder coating material as claimed in any of claims 1 to 9, wherein the dimensionally stable particles are isolated from the suspensions (3) by spray drying or freeze drying.

11. The powder coating material as claimed in any of claims 1 to 10, wherein the dimensionally stable particles are isolated from the emulsions (2) by pressure relief.

12. The powder coating material as claimed in any of claims 1 to 11, wherein at least of the liquid components and/or the aqueous medium comprise at least one emulsifier.

13. The powder coating material as claimed in claim 12, wherein the aqueous solution of the emulsifier at the critical micelle concentration (CMC) has a surface tension >

30 mN/m.

14. The powder coating material as claimed in claim 12 or 13, wherein the emulsifier is selected from the group of copolymers preparable by single-stage or multistage free-radical copolymerization in an aqueous medium of

(a) at least one olefinically unsaturated monomer and

(b) at least one olefinically unsaturated monomer different than the olefinically unsaturated monomer (a) and of the general formula I

R¹R²C═

CR³R⁴ 

 

(I)

 

in which the radicals R¹, R², R³, and R⁴ each independently of one another are hydrogen atoms or substituted or unsubstituted alkyl, cycloalkyl, alkylcycloalkyl, cycloalkylalkyl, aryl, alkylaryl, cycloalkylaryl, arylalkyl or arylcycloalkyl radicals with the proviso that at least two of the variables R¹, R², R³ and R⁴ are substituted or unsubstituted aryl, arylalkyl or arylcycloalkyl radicals, especially substituted or unsubstituted aryl radicals.

15. The powder coating material as claimed in claim 14, wherein the aryl radicals R¹, R², R³ and/or R⁴ of the monomers (b) are phenyl or naphthyl radicals.

16. The powder coating material as claimed in claim 14, wherein the radicals are phenyl radicals.

17. The powder coating material as claimed in any of claims 14 to 16, wherein the substituents in the radicals R¹, R², R³ and R⁴ of the monomers (b) are selected from the group consisting of electron-withdrawing or electron-donating atoms or organic radicals.

18. The powder coating material as claimed in claim 17, wherein the substituents are selected from the group consisting of halogen atoms, nitrile, nitro, partially or fully halogenated alkyl, cycloalkyl, alkylcycloalkyl, cycloalkylalkyl, aryl, alkylaryl, cycloalkylaryl, arylalkyl, and arylcycloalkyl radicals;

aryloxy, alkyloxy, and cycloalkyloxy radicals;

arylthio, alkylthio, and cycloalkylthio radicals, and primary, secondary and/or tertiary amino groups.

19. The powder coating material as claimed in any of claims 14 to 18, wherein at least one monomer (a) is selected from the group of the carboxyl-containing monomers (a3).

20. The powder coating material as claimed in any of claims 12 to 19, wherein the emulsifier is present in the aqueous medium.

21. The powder coating material as claimed in any of claims 1 to 20, curable physically or thermally and/or with actinic radiation.

22. The powder coating material as claimed in any of claims 1 to 21, which is a one-component system.

23. The powder coating material as claimed in any of claims 12 to 22, which is pigmented.

24. A process for preparing a pigmented powder coating material as claimed in any of claims 1 to 23, which comprises

(1) mixing at least two liquid components comprising in each case at least one liquid starting product in a static mixer, to give a molecularly disperse and/or finely dispersed liquid mixture,

(2) emulsifying the liquid mixture (1) in an aqueous medium in a dispersing unit, to give an aqueous emulsion of liquid particles,

(3) cooling the emulsion (2) so that a suspension of dimensionally stable particles is formed, and

(4) isolating the dimensionally stable particles (3) from the suspension,

or alternatively

(3) isolating the dimensionally stable particles directly from the emulsion (2).

25. The process as claimed in claim 24, wherein the aqueous medium in step (2) consists in whole or in part of an aqueous pigment preparation (pigment paste).

26. The use of a powder coating material as claimed in any of claims 1 to 23 as a coating material, adhesive or sealing compound or to prepare a coating material, adhesive, or sealing compound.

27. The use as claimed in claim 26, wherein the coating material, adhesive or sealing compound is curable physically or thermally and/or with actinic radiation.

28. The use as claimed in claim 27, wherein the coating material, adhesive or sealing compound is used to coat, bond, and seal motor vehicle bodies and parts thereof, the interior and exterior of motor vehicles, doors, windows, furniture, and also for coating, bonding, and sealing as part of the industrial coating of small parts, coils, containers, packaging, electrical components, and white goods.