Anionic Electrodepositable Coatings for Low Gloss Durability
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Solution Overview
Problem
Existing electrodeposition coating methods struggle to produce low gloss coatings that retain their finish and corrosion resistance upon exterior exposure, as traditional flatting agents like silicas and alumina silicates discolor and chalk quickly, and require continuous recirculation to maintain paint homogeneity, leading to increased capital and energy costs.
Innovation Solution
An electrodepositable coating composition comprising an acrylic polymer and an anionic salt group containing polymeric dispersant, with a Z-average molecular weight of 200,000 to 2,000,000, which is used in conjunction with an anionic salt group containing polymer to achieve a low gloss coating that maintains performance and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If traditional flatting agents such as silicas and alumina silicates are added to electrodepositable coating compositions, then low gloss levels are achieved, but the finishes discolor and chalk quickly upon exposure to the elements
Solution Approach 1:
The invention changes the chemical composition parameters by replacing traditional inorganic flatting agents (silicas, alumina silicates) with specific organic polymer dispersants having controlled molecular weights (Mz of 200,000 to 2,000,000) and specific chemical structures (anionic salt group containing polymers). This parameter change maintains the gloss-reducing function while eliminating the durability problems of discoloration and chalking.
2Illumination intensity
If traditional flatting agents are added to electrodepositable coating compositions, then low gloss levels are achieved, but continuous recirculation must be employed to maintain paint homogeneity
Solution Approach 1:
The invention changes the density parameter of the dispersant by using organic polymers with molecular weights optimized for suspension stability. These polymers have densities closer to the coating composition matrix compared to dense inorganic flatting agents, eliminating the gravity-driven settlement that necessitates continuous recirculation systems.
3Illumination intensity
If traditional flatting agents are added to electrodepositable coating compositions, then low gloss levels are achieved, but higher capital equipment costs, higher maintenance costs, and higher energy costs result
Solution Approach 1:
The invention extracts and eliminates the need for continuous recirculation equipment by replacing dense inorganic flatting agents with polymer dispersants that maintain homogeneity through molecular interactions rather than mechanical agitation. This removal of the recirculation requirement directly reduces capital equipment costs, maintenance costs, and energy consumption.
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
The composition effectively produces low gloss coatings with improved durability and reduced maintenance costs by stabilizing the coating composition and preventing discoloration and chalking, while maintaining corrosion resistance and paint homogeneity.
Implementation Method 1
an acrylic polymer that is a polymerization product of a dispersion of a polymerizable ethylenically unsaturated monomer composition in a dispersing medium comprising water in the presence of an anionic salt group containing polymeric dispersant
Implementation Method 2
Electrodeposition as a coating application method involves the deposition onto a conductive substrate of a film-forming composition under the influence of an applied electrical potential
Data Source
AI summary
Disclosed herein are anionic electrodepositable coating compositions that are capable of providing cured coatings of low gloss.