Method of forming a passivated pigment slurry for an aqueous topcoat coating composition

Patent metadata

Field	Value
Publication number	US-9777180-B2
Application number	US-201514612954-A
Country	US
Kind code	B2
Filing date	Feb 3, 2015
Priority date	Feb 3, 2015
Publication date	Oct 3, 2017
Grant date	Oct 3, 2017

Abstract

A method of forming a passivated pigment slurry includes combining a resin and a pigment to form a pigment-resin slurry, wherein the pigment includes a plurality of flakes each having a surface. After combining, the method includes mixing the pigment-resin slurry and an orthosilicate to form a coated pigment-resin slurry. The coated pigment-resin slurry includes the resin and a coated pigment including the plurality of flakes each encapsulated by a first layer formed from silica and disposed on the surface. The method further includes reacting the coated pigment-resin slurry and an organosilane compound having a hydrolysable group and an organic functional group to coat the first layer and thereby form the passivated pigment slurry. The passivated pigment slurry includes the resin and a passivated pigment including the plurality of flakes each coated with a second layer disposed on the first layer.

First claim

The invention claimed is:

1. A method of forming a passivated pigment slurry for an aqueous topcoat coating composition, the method comprising:
combining a resin and a pigment to form a pigment-resin slurry, wherein the pigment includes a plurality of flakes each having a surface;
after combining, mixing the pigment-resin slurry and an orthosilicate to form a coated pigment-resin slurry, wherein the coated pigment-resin slurry includes:
the resin; and
a coated pigment including the plurality of flakes each encapsulated by a first layer formed from silica and disposed on the surface; and

reacting the coated pigment-resin slurry and an organosilane compound having a hydrolysable group and an organic functional group to coat the first layer and thereby form the passivated pigment slurry, wherein the passivated pigment-resin slurry includes:
the resin; and
a passivated pigment including the plurality of flakes each coated with a second layer disposed on the first layer.

2. The method of claim 1 , wherein combining includes slurrying the pigment and the resin at a weight ratio of parts by weight pigment to parts by weight resin of from about 0.1:100 to about 50:100.

3. The method of claim 1 , wherein combining further includes slurrying a solvent, a first amine having a logarithmic acid dissociation constant, pK a , of greater than or equal to 9, a second amine having a pK a of less than 9, the pigment, and the resin such that the pigment-resin slurry is a single-phase mixture.

4. The method of claim 1 , wherein mixing includes blending the pigment-resin slurry and the orthosilicate at a temperature of from about 10° C. to about 150° C. for a duration of from about 30 minutes to about 200 hours.

5. The method of claim 1 , wherein mixing includes blending about 60 parts by weight of the orthosilicate and about 100 parts by weight of the pigment.

6. The method of claim 1 , wherein mixing includes forming the first layer such that the first layer is present in the coated pigment in an amount of from about 10 parts by weight to about 15 parts by weight based on 100 parts by weight of the coated pigment.

7. The method of claim 1 , wherein reacting includes blending the coated pigment-resin slurry and the organosilane compound in a weight ratio of parts by weight organosilane compound to parts by weight plurality of flakes of from about 0.05:100 to about 10:100.

8. The method of claim 1 , wherein reacting includes blending the coated pigment-resin slurry and the organosilane compound at a temperature of from about 10° C. to about 150° C. for a duration of from about 30 minutes to about 200 hours.

9. The method of claim 1 , wherein the surface is formed from aluminum.

10. The method of claim 1 , wherein the surface is formed from titanium dioxide disposed on a mica.

11. The method of claim 1 , wherein mixing includes forming the first layer so that the first layer has a thickness of from about 0.5 nm to about 50 nm.

12. A method of forming an aqueous topcoat coating composition, the method comprising:
combining a resin and a pigment to form a pigment-resin slurry, wherein the pigment includes a plurality of flakes each having a surface;
after combining, mixing the pigment-resin slurry and an orthosilicate to form a coated pigment-resin slurry, wherein the coated pigment-resin slurry includes:
the resin; and
a coated pigment including the plurality of flakes each encapsulated by a first layer formed from silica and disposed on the surface;

reacting the coated pigment-resin slurry and an organosilane compound having a hydrolysable group and an organic functional group to coat the first layer and thereby form a passivated pigment slurry, wherein the passivated pigment slurry includes:
the resin; and
a passivated pigment including the plurality of flakes each coated with a second layer disposed on the first layer; and

blending the passivated pigment slurry, water, and at least one water-miscible film-forming binder to form the aqueous topcoat coating composition.

13. The method of claim 12 , further including, prior to blending, storing the passivated pigment slurry in a container for longer than 15 consecutive days without agitating the passivated pigment slurry.

14. The method of claim 13 , wherein the container has a volume, and further including, prior to blending, storing the passivated pigment slurry in the container for longer than 30 consecutive days such that the passivated pigment slurry settles to define a first portion that is substantially free from the plurality of flakes and a second portion that includes the plurality of flakes, and further wherein the second portion occupies greater than or equal to 75% of the volume.

15. The method of claim 12 , further including blending a colloidal layered silicate, the passivated pigment slurry, water, and the at least one water-miscible film-forming binder.

16. The method of claim 12 , further including, prior to blending, exposing the passivated pigment slurry to water without corroding the passivated pigment slurry.

17. The method of claim 12 , wherein blending includes adding to water from about 0.1 part by weight passivated pigment to about 30 parts by weight passivated pigment based on 100 parts by weight of the at least one water-miscible film-forming binder.

18. A method of forming an aqueous topcoat coating system, the method comprising:
combining a resin and a pigment to form a pigment-resin slurry, wherein the pigment includes a plurality of flakes each having a surface;
after combining, mixing the pigment-resin slurry and an orthosilicate to form a coated pigment-resin slurry, wherein the coated pigment-resin slurry includes:
the resin; and
the plurality of flakes each encapsulated by a first layer formed from silica and disposed on the surface;

reacting the coated pigment-resin slurry and an organosilane compound having a hydrolysable group and an organic functional group to coat the first layer and thereby form a passivated pigment slurry, wherein the passivated pigment slurry includes:
the resin; and
the plurality of flakes each coated with a second layer disposed on the first layer;

blending the passivated pigment slurry, water, and at least one water-miscible film-forming binder to form an aqueous topcoat coating composition;
applying a film formed from the aqueous topcoat coating composition to a substrate; and
curing the film to form the aqueous topcoat coating system.

19. The method of claim 18 , wherein the aqueous topcoat coating system includes the substrate and a cured film formed from the aqueous topcoat coating composition and disposed on the substrate, and further including, after curing, exposing the cured film to light without photo-degrading the cured film.

Assignees

• Basf Coatings Gmbh

Inventors

• Campbell Donald H
• Thanki Paragkumar
• Rathod Rajesh

Classifications

• C09D5/36 Primary

  Pearl essence, e.g. coatings containing platelet-like pigments for pearl lustre · CPC title

• C08K13/06

  Pretreated ingredients and ingredients covered by the main groups C08K3/00 - C08K7/00 · CPC title

• C08K9/10

  Encapsulated ingredients · CPC title

• C09D7/70

  characterised by shape, e.g. fibres, flakes or microspheres · CPC title

• C09D17/004 Primary

  containing an inorganic pigment · CPC title