Epoxy Imbibed Polymer Particles Latex Stability
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Solution Overview
Problem
Existing polymer latexes face challenges in incorporating high concentrations of thermosettable compounds while maintaining particle stability, especially under heat-age stability testing, due to reactivity issues with carboxylate salts and the limitations of incorporating epoxy resins.
Innovation Solution
A stable aqueous dispersion of thermoplastic polymer particles imbibed with a thermosettable compound, characterized by anti-agglomerating functional groups such as amide, acetoacetoxy, and strong protic acids, allowing for high concentrations of thermosettable compounds like novolac resins or glycidyl ethers, without a hardener, and maintaining stability at elevated temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If carboxylic acid or carboxylate groups are included in the polymer to enhance stability, then latex stability is improved, but reactivity toward thermosettable compounds causes particle instability
Solution Approach 1:
The patent changes the chemical nature of the stabilizing groups from carboxylic acid/carboxylate groups to amide, acetoacetoxy, or strong protic acid groups. These alternative groups provide the necessary colloidal stability through electrostatic or steric mechanisms without the harmful nucleophilic reactivity toward epoxy rings that characterizes carboxylate salts, thereby resolving the contradiction between stability enhancement and reactivity-induced instability.
Solution Approach 2:
The patent employs sacrificial stabilizing groups (amide, acetoacetoxy, or strong protic acid groups) that can be present in high concentrations without causing crosslinking. These groups serve their stabilizing function during storage and application, and their temporary presence is acceptable since the final cured product achieves superior performance through the epoxy-hardener reaction.
2Stability of the object's composition
If concentration of acid monomer is increased to improve stability, then latex stability is enhanced, but film blistering and increased associative thickener demand occur
Solution Approach 1:
The patent fundamentally changes the type of stabilizing functional groups from carboxylic acid groups to amide, acetoacetoxy, or strong protic acid groups. This parameter change allows achieving the same colloidal stability function without the harmful side effects of film blistering and excessive thickener demand that are associated with high acid monomer concentrations.
3Strength
If concentration of thermosettable compound is increased to improve handling performance and wet strength, then performance is enhanced, but latex particle instability occurs due to reactivity with carboxylate salts
Solution Approach 1:
The patent changes the chemical composition of the polymer particles to include amide, acetoacetoxy, or strong protic acid groups instead of carboxylate salts. This allows incorporating high concentrations of thermosettable compounds (20-60 weight percent) to achieve improved handling performance and wet strength while maintaining particle stability during storage and application.
4Object-generated harmful factors
If pH is lowered to suppress reactivity of acid groups, then reactivity is reduced, but colloidal stability of the latex is compromised
Solution Approach 1:
Instead of adjusting pH to suppress reactivity, the patent changes the chemical identity of the stabilizing groups to amide, acetoacetoxy, or strong protic acid groups. These groups inherently provide stability through non-nucleophilic mechanisms (electrostatic repulsion or steric hindrance) and do not require pH suppression to prevent unwanted reactions with thermosettable compounds, thus maintaining colloidal stability across a broader pH range.
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 solution enables the formation of a heat-age stable polymer latex with high thermosettable compound concentrations, suitable for coatings, adhesives, and sealants, without VOCs and with improved chemical and wet strength, overcoming previous stability limitations.
Implementation Method 1
the polymer particles are characterized by having a sufficient concentration of anti-agglomerating functional groups... having at least two oxirane groups, which polymer particles are characterized by having a sufficient concentration of anti-agglomerating functional groups
Implementation Method 2
stable aqueous dispersion of thermoplastic polymer particles imbibed with a thermosettable compound... characterized by anti-agglomerating functional groups such as amide, acetoacetoxy, and strong protic acids
Implementation Method 3
contacting the composition of any of Claims 1 to 7 with a hardener to form a curable composition... curing the applied composition... thermosettable compound having at least two oxirane groups
Data Source
AI summary
The present invention relates to a stable aqueous dispersion of thermoplastic polymer particles imbibed with a thermosettable compound. The polymer particles are characterized by having a sufficient concentration of anti-agglomerating functional groups to stabilize the latex against agglomeration. The dispersion is useful as one part of a two-pack formulation.