Method for producing a multicoat paint system on plastics substrates

Patent metadata

Field	Value
Publication number	US-2018141084-A1
Application number	US-201615571515-A
Country	US
Kind code	A1
Filing date	Mar 31, 2016
Priority date	May 6, 2015
Publication date	May 24, 2018
Grant date	—

Abstract

The present invention relates to a method for producing a multicoat paint system on a plastics substrate, in which a basecoat film or a plurality of directly successive basecoat films are produced on a plastics substrate, a clearcoat film is produced directly on the one basecoat film or on the topmost of the plurality of basecoat films, and subsequently the one or more basecoat films and the clearcoat film are jointly cured, this method being a method wherein at least one basecoat material used for the production of the basecoat films comprises at least one aqueous polyurethane-polyurea dispersion (PD) comprising polyurethane-polyurea particles, where the polyurethane-polyurea particles present in the dispersion (PD) comprise anionic groups and/or groups which can be converted into anionic groups, and have an average particle size of 40 to 2000 nm and also a gel fraction of at least 50%.

First claim

1 . A method for producing a paint system on a plastics substrate, comprising
(1) producing a basecoat film or a plurality of directly successive basecoat films on the plastics substrate by applying an aqueous basecoat material to the substrate or directly successively applying a plurality of basecoat materials to the substrate, (2) producing a clearcoat film directly on the basecoat film or a topmost basecoat film by applying a clearcoat material directly to the basecoat film or the topmost basecoat film, (3) jointly curing the basecoat film and the clearcoat film or the basecoat films and the clearcoat film, wherein the basecoat material or at least one of the basecoat materials comprises at least one aqueous polyurethane-polyurea dispersion comprising polyurethane-polyurea particles, where the polyurethane-polyurea particles present in the dispersion comprise anionic groups and/or groups which can be converted into anionic groups, and have an average particle size of 40 to 2000 nm and also a gel fraction of at least 50%.

2 . The method of claim 1 , wherein the polyurethane-polyurea particles comprise, in each case in reacted form,
at least one polyurethane prepolymer containing isocyanate groups and comprising anionic groups and/or groups which can be converted into anionic groups, and at least one polyamine comprising two primary amino groups and one or two secondary amino groups, and the dispersion comprises to an extent of at least 90 wt % of the polyurethane-polyurea particles and also water.

3 . The method of claim 1 , wherein the anionic groups and/or groups which can be converted into anionic groups are carboxylate and/or carboxylic acid groups.

4 . The method of claim 2 , wherein the polyamine consists of one or two secondary amino groups, two primary amino groups, and also aliphatically saturated hydrocarbon groups.

5 . The method of claim 1 , wherein the polyurethane-polyurea particles present in the dispersion have an average particle size of 110 to 500 nm and a gel fraction of at least 80%.

6 . The method of claim 1 , wherein the basecoat material or at least one of the basecoat materials additionally comprise(s) at least one hydroxy-functional polymer as binder, selected from the group consisting of polyurethanes, polyesters, polyacrylates, and copolymers of these polymers.

7 . The method of claim 1 , wherein the basecoat material or at least one of the basecoat materials, is/are one-component coating compositions.

8 . The method of claim 1 , wherein the joint curing (3) is carried out at a temperature between 40 and 100° C. for a period of 5 to 60 minutes.

9 . The method of claim 1 , wherein the plastics substrate comprises polypropylene/ethylene-propylene-diene copolymer blends.

10 . The method of claim 1 , wherein the basecoat material and the basecoat materials, if they comprise at least one crosslinking agent, have a solids content of at least 25% and, if the basecoat material and the basecoat materials (b.1.2.x) contain no crosslinking agent, have a solids content of at least 15%.

11 . The method of claim 10 , wherein the basecoat materials at 23° C. under a shearing load of 1000 l/s have a viscosity of 40 to 150 mPa·s.

12 . The method of claim 1 , wherein the basecoat material or at least one of the basecoat materials comprise(s) at least one crosslinking agent selected from the group consisting of blocked polyisocyanates and aminoplast resins.

13 . The method of claim 2 , wherein the prepolymer comprises at least one polyester diol prepared using diols and dicarboxylic acids, at least 50 wt %, preferably 55 to 75 wt %, of the dicarboxylic acids used in preparing the polyester diols being dimer fatty acids.

14 . The method of claim 1 , wherein the basecoat material or the basecoat materials are applied by electrostatic spray application or pneumatic spray application.

15 . A multicoat paint system which has been produced by the method of claim 1 .

Assignees

• Basf Coatings Gmbh

Inventors

• Bauer Juergen
• Andersen Audree
• Reuter Hardy
• Ratz Roland
• Buermann Marita
• Winnen Sina
• Diepenbrock Vera

Classifications

• C08G18/0823

  containing carboxylate salt groups or groups forming them · CPC title

• B05D2201/02

  Polymeric substrate · CPC title

• C09D175/00

  Coating compositions based on polyureas or polyurethanes; Coating compositions based on derivatives of such polymers · CPC title

• B05D7/02 Primary

  to macromolecular substances, e.g. rubber (treatment or coating of shaped articles made of macromolecular substances C08J7/00) · CPC title

• B05D7/532 Primary

  the two layers being cured or baked together, i.e. wet on wet · CPC title