Waterborne Base Coat Additives for Light Metallic Color
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Solution Overview
Problem
Current automotive coating processes for base coat/clear coat two-layer coatings with light metallic colors require an additional pneumatic spray-application step, leading to significant overspray paint loss and compromising the lightness flop performance.
Innovation Solution
Incorporating a specific additive combination of poly(meth)acrylic acid thickener and non-ionically emulsified EVA copolymer wax with a drop point of 80 to 110°C into the waterborne base coat, allowing for electrostatically assisted high-speed rotary atomization of the base coat layer without the need for pneumatic application, while maintaining the lightness flop performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If pneumatic spray-application is used to achieve optimum orientation of special-effect pigments, then lightness flop performance is improved, but overspray paint loss increases significantly
Solution Approach 1:
The patent changes the physical-chemical parameters of the base coat composition by incorporating specific additives (poly(meth)acrylic acid thickener and non-ionically emulsified EVA copolymer wax) that modify the coating's flow and leveling properties. This allows the coating to achieve proper pigment orientation and lightness flop performance through electrostatically assisted high-speed rotary atomization alone, without requiring pneumatic spray-application, thereby reducing overspray loss.
2Productivity
If electrostatically assisted high-speed rotary atomization is used for base coat application, then productivity is improved, but lightness flop performance deteriorates
Solution Approach 1:
The patent modifies the base coat composition by adding poly(meth)acrylic acid thickener and non-ionically emulsified EVA copolymer wax, which change the coating's rheological properties and leveling characteristics. This enables the coating to maintain proper pigment orientation and achieve lightness flop performance even when applied solely by electrostatically assisted high-speed rotary atomization, thus preserving both productivity and quality.
Solution Approach 2:
The patent creates a composite base coat system combining traditional binder components with specific functional additives (poly(meth)acrylic acid thickener and non-ionically emulsified EVA copolymer wax). This composite formulation enhances the coating's ability to level and orient pigments during electrostatic spray-application, ensuring lightness flop performance is maintained while using only the high-speed rotary atomization process.
3Manufacturing precision
If additional pneumatic spray-application step is added to achieve optimum pigment orientation, then lightness flop performance is improved, but device complexity increases
Solution Approach 1:
The patent extracts and eliminates the unnecessary pneumatic spray-application step from the conventional two-step process. By formulating the base coat with specific additives (poly(meth)acrylic acid thickener and non-ionically emulsified EVA copolymer wax), the coating achieves proper pigment orientation and lightness flop performance through electrostatically assisted high-speed rotary atomization alone, simplifying the application process while maintaining quality.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables the spray-application of base coat layers with light metallic colors using only electrostatically assisted high-speed rotary atomization, reducing overspray loss and ensuring the desired lightness flop performance, thus meeting the specifications of car manufacturers.
Implementation Method 1
non-ionically emulsified EVA copolymer wax with a drop point of the wax portion of 80 to 110°C
Implementation Method 2
poly(meth)acrylic acid thickener
Implementation Method 3
electrostatically assisted high-speed rotary atomization
Data Source
AI summary
A waterborne base coat having a light metallic color and containing 0.5 to 2 wt.-% of poly(meth)acrylic acid thickener and 2 to 7 wt.-% of non-ionically emulsified EVA copolymer wax with a drop point of the wax portion of 80 to 110°C, the wt.-% in each case calculated as solids and relative to the solids content of the waterborne base coat.