Derivatized Polyamine Coatings for Rapid Setting and Weathering Resistance
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Solution Overview
Problem
Existing quick-setting coatings for exterior surfaces suffer from reduced elongation at break and significant yellowing upon weathering, making them unsuitable for many applications, particularly due to the impact of rainfall during and after application.
Innovation Solution
The development of quick-setting aqueous coating compositions comprising an anionically stabilized copolymer, a derivatized polyamine, and a volatile base, which exhibit rapid setting times while maintaining non-yellowing properties and suitable physical properties, such as elongation at break, for various exterior applications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If setting additives are incorporated into coatings to decrease setting time, then the coating exhibits quick-setting behavior, but the coating suffers from decreased elongation at break and significant yellowing upon weathering
Solution Approach 1:
The patent changes the chemical parameters of the polyamine component by using derivatized polyamines with specific molecular weights (5,000-5,000,000 Daltons) and degrees of nitrogen-derivatization (5-100%). This modifies the reactivity and curing characteristics of the polyamine, enabling faster setting times while maintaining the physical properties of the cured coating, thus resolving the contradiction between quick-setting behavior and retention of elongation at break.
Solution Approach 2:
The patent creates a composite curing system by combining derivatized polyamines with anionically stabilized copolymers containing specific functional groups. This composite approach allows the derivatized polyamine to provide rapid initial setting while the copolymer matrix maintains the mechanical properties and weathering resistance, effectively resolving the contradiction between speed of cure and quality of final coating.
2Loss of time
If setting additives are incorporated into coatings to decrease setting time, then the coating exhibits quick-setting behavior, but the coating exhibits significant yellowing upon weathering
Solution Approach 1:
The patent modifies the chemical structure parameters of the polyamine by applying derivatization processes that reduce yellowing tendency. The derivatized polyamines maintain the necessary reactivity for quick setting while the modified structure resists oxidation and UV degradation that cause yellowing, thus resolving the contradiction between fast setting and color stability.
Solution Approach 2:
The volatile base component serves a temporary function during the curing process, providing the necessary alkaline environment for the derivatized polyamine to react and set the coating quickly, then evaporates completely. This temporary agent enables rapid setting without leaving residues that would cause yellowing, resolving the contradiction between speed of cure and long-term color stability.
3Reliability
If rainfall occurs during and after coating application, then coating failure occurs due to wash-off, but shortening setting time is needed to prevent this
Solution Approach 1:
The patent optimizes the reactivity parameters of the derivatized polyamine to achieve rapid curing that establishes sufficient crosslinking density quickly. This rapid network formation creates immediate resistance to water penetration and wash-off, resolving the contradiction between needing fast protection from rainfall and maintaining adequate curing time for proper adhesion and flexibility.
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 coating compositions achieve rapid setting times with enhanced durability and resistance to weathering, maintaining tensile strength and elongation at break even after 1,000 hours of accelerated weathering, thus addressing the limitations of existing coatings.
Implementation Method 1
quick-setting aqueous coating compositions comprising an anionically stabilized copolymer, a derivatized polyamine
Implementation Method 2
The coating compositions also contain a volatile base
Data Source
AI summary
Disclosed herein are aqueous coating compositions containing an anionically stabilized polymer, one or more derivatized polyamines, and a volatile base. Coating compositions can further include one or more additional copolymers, which may or may not be anionically stabilized, and/or additional additives, including pigments, defoamers, pigment dispersing agents, thickeners, surfactants, and combinations thereof. By incorporating a derivatized polyamine, such as an alkoxylated polyamine, the setting time of the coating compositions can be decreased. Also provided are coatings formed from the coating compositions described herein, as well as methods of forming these coatings.