Waterborne Epoxy Coating Composition for Stable Particle Dispersion
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Solution Overview
Problem
Conventional water-based coating compositions face stability issues when inorganic materials are added to Part A due to the reaction of acrylic carboxylate groups of the acrylic polymer dispersant with oxirane groups of the epoxy, leading to increased difficulty in mixing the two components.
Innovation Solution
A water-based coating composition comprising Part A with a waterborne epoxy dispersion, polymeric dispersant containing anti-agglomerating functional groups unreactive with oxirane groups, and inorganic particles, and Part B with a curing agent, where the polymeric dispersant effectively disperses the inorganic particles in Part A.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a conventional acrylic polymer dispersant is used in Part A for grinding inorganic particles, then the inorganic particles can be dispersed, but colloidal stability deteriorates due to reaction between acrylic carboxylate groups and oxirane groups of epoxy
Solution Approach 1:
The harmful carboxylate groups are extracted/removed from the dispersant structure. The patent uses polymer dispersants with non-reactive functional groups (such as hydroxyl groups or inert hydrocarbon chains) instead of conventional acrylic carboxylate dispersants, eliminating the source of the harmful reaction while maintaining dispersant functionality.
Solution Approach 2:
A polymer dispersant with non-reactive functional groups acts as an intermediary between inorganic particles and epoxy resin. This mediator provides steric hindrance and electrostatic repulsion to maintain colloidal stability without chemically reacting with the epoxy oxirane groups, thus preventing coagulation.
2Stability of the object's composition
If inorganic materials and dispersants are added in Part B, then colloidal stability is maintained, but mixing difficulty increases due to increased amount of Part B
Solution Approach 1:
The dispersant function is extracted from Part B and relocated to Part A. By using a non-reactive polymer dispersant in Part A, the system eliminates the need to add dispersants in Part B, maintaining the original two-pack mixing ratio and ease of operation while ensuring colloidal stability.
Solution Approach 2:
The dispersant is pre-added in Part A before mixing with Part B. The non-reactive polymer dispersant is incorporated into the epoxy resin in advance, creating a stable dispersion system that remains stable during storage and mixing, eliminating the need for additional dispersant addition in Part B.
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 maintains stability during storage and mixing, ensuring effective application without coagulation, as demonstrated by low viscosity changes and stable in-can appearance even after heat aging.
Implementation Method 1
a polymeric dispersant which comprises anti-agglomerating functional groups that are unreactive with oxirane groups of the epoxy dispersion
Implementation Method 2
The polymeric dispersant comprises anti-agglomerating functional groups that are unreactive with oxirane groups of the epoxy dispersion
Implementation Method 3
the concentration of the anti-agglomerating functional groups in the acrylic polymer is sufficient to stabilize the epoxy resin under heat-age conditions
Implementation Method 4
the concentration of the anti-agglomerating functional groups in the acrylic polymer is sufficient to stabilize the epoxy resin under heat-age conditions
Data Source
AI summary
A water-based coating composition containing two parts (Parts A and B), (A) binder component containing a waterborne epoxy dispersion and dispersed inorganic particles with a polymeric dispersant and (B) hardener component. The polymeric dispersant contains anti-agglomerating functional groups that are unreactive with oxirane groups of the epoxy dispersion.