Lactam-Functionalized Polymer Coatings Extend Open Time
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Solution Overview
Problem
Water-borne latex paints have a short open time compared to solvent-borne paints, and traditional methods to extend open time, such as adding co-solvents, lead to issues like increased volatile organic compounds (VOC) and reduced block resistance.
Innovation Solution
Incorporating at least 0.5 wt % of a lactam-functionalized polymer with a polymer backbone, such as polyacetal polyether, polyhemiaminal polyether, or polyaminal polyether, into the aqueous coating composition to increase open time while maintaining desired rheology properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If co-solvents are added to extend open time, then open time is improved, but volatile organic compound emission increases
Solution Approach 1:
The invention changes the chemical parameter of the coating composition by incorporating lactam-functionalized polymers with specific molecular structures (polyacetal polyether, polyhemiaminal polyether, or polyaminal polyether backbones). This chemical parameter change enables extension of open time through a different mechanism than co-solvents, avoiding VOC emissions while achieving the desired duration extension.
Solution Approach 2:
The invention uses composite material strategy by combining lactam-functionalized polymers with water-borne latex paint systems. The lactam-functionalized polymer acts as a functional additive that modifies the coating's open time properties without introducing harmful co-solvents, creating a composite coating composition that achieves both extended open time and low VOC content.
2Duration of action of moving object
If co-solvents are added to extend open time, then open time is improved, but block resistance decreases
Solution Approach 1:
The invention changes the rheological and chemical parameters of the coating by using lactam-functionalized polymers. These polymers modify the film formation process and particle coalescence behavior through their specific molecular structure, extending open time while maintaining adequate block resistance, unlike co-solvents that compromise block resistance.
Solution Approach 2:
The lactam-functionalized polymer acts as an intermediary substance that mediates between the conflicting requirements of extended open time and maintained block resistance. It provides a bridging mechanism that allows slower film formation (extending open time) while still enabling proper particle coalescence and film integrity (maintaining block resistance).
3Object-generated harmful factors
If water content is reduced in high volume solids formulations, then VOC is reduced, but open time extension becomes more challenging
Solution Approach 1:
The invention changes the functional parameters of the polymer additives by using lactam-functionalized polymers with specific molecular architectures. These structural changes enable the polymers to effectively extend open time even in high volume solids, low water-content formulations, overcoming the limitation that normally makes open time extension more difficult in such systems.
Solution Approach 2:
The lactam-functionalized polymers perform preliminary action by delaying the film formation process and extending the workable period before the coating sets. This preliminary extension of open time occurs during the application and rework period, allowing painters to complete their work even in high volume solids formulations where water content is limited.
Data Source
AI summary
An aqueous coating composition comprising at least 0.5 wt % of a lactam-functionalized polymer is disclosed. The lactam-functionalized polymer includes lactam-functionalized polyacetal polyether, polyhemiaminal polyether or polyaminal polyether. The aqueous coating composition can increase an open time of a water-borne latex paint. A method of increasing an open time for an aqueous coating composition of a water-borne latex paint using the lactam-functionalized polymer is also disclosed.