Aqueous Polymer Dispersion with Reactive Flow Promoter
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Solution Overview
Problem
Coatings based on unsaturated oils suffer from durability limitations, while aqueous dispersions of polymers formed from ethylenically unsaturated monomers offer superior durability but lack desirable performance characteristics that come from curing reactions after application.
Innovation Solution
Aqueous compositions with high levels of unsaturated flow promoters and polymer particles that include copolymers formed by polymerizing ethylenically unsaturated nonionic monomers and monomers with pendant functionality, which react with the flow promoters upon drying and exposure to oxygen, enhancing penetration and crosslinking in porous substrates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If coatings based on unsaturated oils are used, then desirable performance properties such as film hardness are achieved, but durability is limited
Solution Approach 1:
The patent combines aqueous dispersion polymers (providing durability) with unsaturated flow promoters containing reactive pendant functionality (providing film hardness through oxidative curing). This merging allows the coating to simultaneously achieve the durability of water-based systems and the hardness of oil-based curing systems.
Solution Approach 2:
The invention creates a composite coating system where polymer particles with pendant functional groups (acetoacetate, hydroxyl, or carboxyl groups) are combined with unsaturated flow promoters (drying or semi-drying oils). The resulting composite material exhibits both the weathering resistance of aqueous polymers and the crosslinked hardness of oxidized oil films.
2Reliability
If aqueous dispersions of polymers formed from ethylenically unsaturated monomers are used, then superior durability is achieved, but desirable performance characteristics from curing reactions are lost
Solution Approach 1:
The polymer particles are equipped with pendant functional groups (acetoacetate, hydroxyl, or carboxyl groups) that automatically react with unsaturated flow promoters upon application and drying. This self-service mechanism enables the aqueous dispersion to autonomously develop curing characteristics without requiring additional chemical additives or complex processing steps.
Solution Approach 2:
The invention modifies the chemical parameters of the aqueous polymer by incorporating pendant functional groups that can undergo oxidation and crosslinking reactions. This parameter change transforms the inert aqueous dispersion into a reactive system capable of forming crosslinked networks similar to traditional oil-based coatings.
3Length of moving object
If high levels of unsaturated flow promoters are incorporated into polymer particles, then deep penetration into porous substrates is achieved, but the composition complexity increases
Solution Approach 1:
The flow promoter is segmented into two functional components: (1) unsaturated hydrocarbon chains that provide low viscosity and penetration capability, and (2) reactive pendant functionality that enables crosslinking for durability. This segmentation allows each component to perform its specific function while maintaining overall system simplicity.
Solution Approach 2:
The unsaturated flow promoter serves multiple functions simultaneously: (1) acts as a plasticizer to reduce polymer viscosity and enhance flow into porous substrates, (2) provides reactive groups for oxidative curing to develop film hardness, and (3) contributes to the overall durability of the coating system. This multi-functionality reduces the need for separate additives.
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 compositions achieve deep penetration into porous substrates, providing superior substrate protection and durability while maintaining an environmentally friendly approach, overcoming the limitations of latex polymer flow and tackiness in coatings for wood and masonry.
Implementation Method 1
monomers bearing a pendant functionality which can react with the unsaturated flow promoter upon drying and exposure to oxygen
Data Source
AI summary
An aqueous composition comprising dispersed particles comprising: at least one unsaturated flow promoter and at least one copolymer formed by the polymerization of at least one ethylenically unsaturated nonionic monomer and at least one monomer bearing a pendant functionality which can react with the unsaturated flow promoter upon drying and exposure to oxygen.