Epoxy Viscous Agent for Cationic Electrodeposition Coatings
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Solution Overview
Problem
Existing cationic electrodeposition coating materials face issues with insufficient film thickness at sharp edges, leading to inadequate corrosion resistance due to low compatibility between resin components, resulting in poor smoothness and edge coverage.
Innovation Solution
A method for producing an epoxy viscosity agent by reacting an amine compound with a chain-extended epoxy resin, followed by dispersion and high molecular weight achievement, to enhance film thickness and edge corrosion resistance in cationic electrodeposition coatings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If silica particles are used to enhance edge covering property, then edge corrosion resistance is improved, but coating film smoothness deteriorates due to aggregation
Solution Approach 1:
The invention extracts and removes the silica particles component from the coating system. Instead of using silica particles to provide viscosity and edge coverage, the patent uses a different mechanism based on the specific molecular weight distribution of the epoxy resin itself to achieve the same functional benefits without the aggregation problems that silica particles cause.
Solution Approach 2:
The invention changes the parameter of epoxy resin molecular weight distribution, specifically controlling the proportion of high molecular weight fraction (100,000 or more) to be 13.0 to 18.0% by mass. This parameter change allows the resin to provide sufficient viscosity and edge coverage without requiring silica particles, thereby maintaining smoothness while improving edge corrosion resistance.
2Reliability
If resin components are used to form coating film, then corrosion resistance is provided, but compatibility is low causing aggregation and poor smoothness
Solution Approach 1:
The invention changes the molecular weight distribution parameters of the epoxy resin, specifically controlling the high molecular weight fraction (100,000 or more) to be 13.0 to 18.0% by mass. This parameter optimization improves the compatibility and structural viscosity behavior of the resin components, preventing aggregation while maintaining corrosion resistance and smoothness.
3Quantity of substance
If conventional epoxy resin is used, then coating formation is achieved, but edge coverage is insufficient due to low film thickness at sharp portions
Solution Approach 1:
The invention changes the molecular weight distribution of the epoxy resin by controlling the proportion of high molecular weight fraction (100,000 or more) to be 13.0 to 18.0% by mass. This creates structural viscosity that prevents shrinkage during curing, ensuring sufficient film thickness at edge portions and improving edge corrosion resistance while maintaining overall coating 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
The method results in a thicker film with improved edge corrosion resistance, ensuring better coverage and corrosion protection at sharp edges without compromising smoothness.
Implementation Method 1
reacting an amine compound with a chain-extended epoxy resin
Implementation Method 2
neutralizing some or all of the amino groups of the resulting amine-modified epoxy resin with an acid and dispersing the resin in a water solvent
Implementation Method 3
a high molecular weight achievement step of mixing and reacting the resulting dispersion with a polyphenol polyglycidyl ether type epoxy resin to obtain an epoxy viscosity agent
Data Source
Figure 1
AI summary
The objective of the present invention is to improve the edge corrosion resistance of a cationic electrodeposition coating composition. The present invention provides a method for producing an epoxy viscous agent for a cationic electrodeposition coating material, the method comprising: (1) an amine modification step in which an amine-modified epoxy resin is obtained by reacting an amine compound and a chain-extended epoxy resin that is obtained by extending a chain of a polyphenol polyglycidyl ether-type epoxy resin and has a material having a relative molecular weight of 100,000 or more in a proportion of 13.0-18.0 mass%, (2) a dispersion step in which a portion or the entirety of an amine group of the obtained amine-modified epoxy resin is neutralized with an acid and dispersed in an aqueous solvent, and (3) a high molecular weight obtaining step in which an obtained dispersion is mixed and reacted with a polyphenol polyglycidyl ether-type epoxy resin to obtain an epoxy viscous agent. Also provided is a cationic electrodeposition coating composition including said epoxy viscous agent.