Emulsion Aggregation Process for Uniform Powder Coatings
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Solution Overview
Problem
Conventional powder coating processes produce coatings with irregularly shaped particles of varying sizes, leading to non-uniform thickness and economic inefficiencies, as they require pulverization and classification methods.
Innovation Solution
The emulsion aggregation and coalescence process creates powder coating compositions with uniformly sized, small particles by aggregating and coalescing resin particles, allowing for the formation of powders with a narrow size distribution without the need for pulverization or classification, and incorporating additives like curing agents and colorants.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional extrusion and pulverization methods are used to produce powder coating compositions, then the production process is established and can be implemented, but the resulting particles are irregularly shaped with wide size ranges leading to non-uniform coating thickness
Solution Approach 1:
Instead of starting with bulk resin and breaking it down into particles through pulverization, the invention inverts the approach by starting with liquid resin and building up particles through controlled aggregation and coalescence. This eliminates the need for complex pulverization and classification equipment while producing uniform particles.
Solution Approach 2:
The invention changes the physical state parameter of the resin from solid (requiring pulverization) to liquid (enabling direct particle formation). By controlling temperature, humidity, and aggregation conditions, uniform particles are formed directly without mechanical size reduction equipment.
2Manufacturing precision
If larger powder particles are used in coating applications, then the powder coating process can be simplified, but the coating thickness becomes unnecessarily thick and non-uniform
Solution Approach 1:
The invention segments the coating material into uniformly sized fine particles with narrow size distribution. This segmentation allows for controlled, thin film deposition with uniform thickness, eliminating the need for excessive material application that occurs with larger, irregular particles.
3Ease of manufacture
If conventional powder production methods are used, then existing manufacturing capabilities can be utilized, but economic inefficiencies arise due to material waste and additional processing steps
Solution Approach 1:
The invention performs preliminary particle formation during the resin liquidation process itself, rather than requiring separate pulverization and classification steps. This preliminary action integrates multiple operations into one process, improving economic feasibility by reducing material waste and processing steps.
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
This process results in more uniform, environmentally friendly coatings with higher solids loading and fewer imperfections, enabling thin film coatings of consistent thickness and improved economic feasibility.
Implementation Method 1
aggregating the particles to form aggregated particles
Implementation Method 2
coalescing the aggregated particles to form fused particles
Implementation Method 3
the powder coating particles are electrostatically charged by the spray gun
Implementation Method 4
The charge on the powder coating particles is normally applied by interaction of the particles with ionized air (corona charging)
Implementation Method 5
The powder particles that come into contact with the preheated surface melt and adhere to the work piece
Data Source
AI summary
A process for forming curable powder comprises providing an aqueous dispersion of particles of curable resin and optionally particles comprising at least one curing agent; aggregating the particles optionally with the curing agent to form aggregated particles; coalescing the aggregated particles to form fused particles; and removing the fused particles from the aqueous dispersion. By this process, a curable powder is formed. The curable powder may be used in powder coating.