Polyamine Additive Side-Chains for Stable, Fast Film Formation
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Solution Overview
Problem
Existing polyamine additives in waterborne coating compositions face issues with shelf-life stability and slow film formation, leading to undesirable interactions with polymer binder particles during storage and prolonged drying times, especially in thick applications.
Innovation Solution
Incorporating poly(alkylene oxide) side-chains into the polyamine additive, which sterically hinders amine groups from interacting with anionic groups on polymer particles at high pH, allowing for faster film formation and improved moisture permeability, resulting in a water-resistant film surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If conventional polyamine additives are used in waterborne coating compositions, then film formation is accelerated, but shelf-life stability deteriorates due to undesirable interactions with polymer binder particles during storage
Solution Approach 1:
The patent introduces poly(alkylene oxide) side-chains as an intermediary structural element between the amine groups and anionic groups on polymer particles. These side-chains act as steric barriers that prevent direct interaction between the polyamine additive and polymer particles during storage, thereby maintaining shelf-life stability while still enabling film formation acceleration through pH change mechanisms.
Solution Approach 2:
The patent applies local quality by creating different functional zones within the polyamine additive structure: the amine groups provide curative activity for film formation, while the poly(alkylene oxide) side-chains provide steric protection and moisture permeability. This localized differentiation of functional properties within a single additive molecule resolves the contradiction between shelf-life stability and film formation speed.
2Productivity
If conventional polyamine additives are used, then initial aggregation of polymer particles is achieved, but moisture permeability and evaporation rates are reduced leading to prolonged drying times
Solution Approach 1:
The poly(alkylene oxide) side-chains create a porous, hydrophilic structure within the polyamine additive that enhances moisture permeability. This allows water molecules to pass through the additive structure more easily, maintaining effective evaporation rates from the coating formulation and preventing prolonged drying times while still enabling proper particle aggregation.
Solution Approach 2:
The patent transitions from a two-dimensional interaction model (amine groups directly contacting particle surfaces) to a three-dimensional structure with poly(alkylene oxide) side-chains extending into the aqueous phase. This dimensional expansion creates additional pathways for moisture transport and maintains evaporation efficiency while preventing premature particle aggregation.
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 polyamine additive enhances shelf-life stability and accelerates film formation, providing a water-resistant coating that resists smudging and rain, while maintaining moisture evaporation rates and barrier properties.
Implementation Method 1
Incorporating poly(alkylene oxide) side-chains into the polyamine additive, which sterically hinders amine groups from interacting with anionic groups on polymer particles at high pH
Implementation Method 2
The interaction of the amine groups of the polyamine is hastened by a pH change (often associated with evaporation of base by volatilization of a volatile amine during drying)
Implementation Method 3
Polyamine additives function with anionically stabilized polymer dispersions and emulsions by being available to interact with anionic groups, such as carboxylic acid, and aggregate multiple polymer particles into aggregates
Data Source
AI summary
Polyamine additives are disclosed that are useful to provide early water resistant to drying anionically colloidally stabilized polymer dispersions in aqueous media. The polyamines are polymerization products from ethylenically unsaturated monomers with pendant tertiary amine groups with ethylenically unsaturated monomers with pendant poly(alkylene oxide) chains of 88 to 1200 g/mole molecular weight.