Low VOC Aqueous Coating Mixer System with Segmented Components
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Solution Overview
Problem
Existing mixer systems for producing aqueous coating materials have high VOC content, which is not suitable for the refinish sector, and lack sufficient storage stability and shade accuracy.
Innovation Solution
A mixer system comprising an aqueous pigment paste A with anionically or nonionically stabilized binders and a pigment-free component B with an acrylate-based microgel dispersion, both with VOC content of less than or equal to 250 g/L, ensuring high storage stability and shade accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If high-solids basecoat systems with solids content greater than 35% are used, then VOC reduction is achieved, but storage stability and effect stability deteriorate
Solution Approach 1:
The coating system is divided into separate components: a water-free base paint containing effect pigments and a water-based mixing varnish. This segmentation allows each component to be optimized independently - the base paint can have high solids content for VOC reduction while the mixing varnish provides the necessary stability when combined
Solution Approach 2:
The invention changes the physical state parameters of the components. The base paint is completely water-free (0% water) while the mixing varnish is aqueous. This parameter change enables the high-solids formulation to achieve low VOC content while maintaining stability through the specific composition of the mixing varnish
2Object-generated harmful factors
If water-thinnable systems with high solids content are used, then VOC content is reduced, but shade accuracy and lightness deteriorate
Solution Approach 1:
By separating the effect pigment-containing base paint from the water-based mixing varnish, the invention maintains shade accuracy. The water-free base paint preserves the optical properties of effect pigments, while the mixing varnish is formulated to not interfere with color matching
Solution Approach 2:
The final coating is a composite of the water-free base paint and the water-based mixing varnish. This composite structure allows the system to combine the VOC-reduction benefits of high solids content with the shade accuracy benefits of proper formulation
3Strength
If crosslinking agents are added to water-thinnable systems, then coating performance is improved, but gassing stability deteriorates
Solution Approach 1:
The invention extracts crosslinking agents from the aqueous component and places them exclusively in the water-free base paint. This extraction eliminates the reaction between water and crosslinking agents that causes gassing, while still providing crosslinking functionality for improved coating performance
4Reliability
If medium-solids basecoat systems with solids content between 20-30% are used, then storage stability is maintained, but VOC content is high
Solution Approach 1:
The invention changes the water content parameter to 0% in the base paint component, transforming it from a medium-solids to a high-solids formulation. This parameter change reduces VOC content while the stability is maintained through the separate component architecture and specific formulation of the mixing varnish
Data Source
AI summary
Described herein is a mixer system for producing aqueous coating materials from at least one aqueous pigment paste A, including at least one color pigment, and at least one pigment-free component B, including an aqueous, acrylate-based microgel dispersion having a glass transition temperature Tg of 50 to 60° C., where both the aqueous pigment paste A and the component B each have a VOC value of less than or equal to 250 g/L. Further described herein is a method for producing aqueous coating materials having a VOC content of 0 to 250 g/L, in which the individual components A and B are stored separately and not mixed until shortly before application, to give the aqueous coating material. Further described herein is a method of using the mixer system for producing aqueous coating materials for refinishing and/or for coating automobile bodies and/or plastics parts.