Multistage Polymer Dispersion for Extended Open Time
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Waterborne acrylic paints have a short open time, limiting the time available for rebrushing without causing defects like brush marks or lap lines, and traditional open time extenders can increase water sensitivity of coating films.
Innovation Solution
A novel aqueous multistage polymer dispersion is developed, comprising a first polymer with diacetone (meth)acrylamide, hydroxy-functional (meth)acrylic acid alkyl ester, and phosphorous-containing acid monomers, and a second polymer with hydrophobic (meth)acrylic acid alkyl esters, carbonyl-containing functional monomers, and hydrophilic monomers, which are polymerized using a multistage free-radical process to extend open time and improve water resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If conventional open time extenders (OTEs) with surfactant nature are added to aqueous acrylic polymer binders, then open time is extended, but water sensitivity of coating films increases
Solution Approach 1:
The invention changes the chemical composition parameters of the polymer binder by incorporating specific functional monomers (carboxyl-containing, hydroxyl-containing, and amino-containing monomers) in controlled amounts. This modifies the polymer's inherent properties to provide both extended open time and maintained water resistance without relying on conventional surfactant-based OTEs that compromise water sensitivity
Solution Approach 2:
The invention creates a composite polymer system by copolymerizing multiple monomer types (acrylic, carboxyl-containing, hydroxyl-containing, and amino-containing monomers) in a multistage process. This composite structure integrates multiple functions: the acrylic provides base film formation, while the functional monomers collectively provide extended open time through controlled polarity and intermolecular interactions, while maintaining water resistance through balanced hydrophobic-hydrophilic characteristics
2Object-affected harmful factors
If waterborne acrylic polymers are used in coating compositions, then environmental friendliness is improved compared to solvent based paints, but open time becomes short
Solution Approach 1:
The invention modifies the polymer composition parameters by incorporating functional monomers with specific polarity characteristics (carboxyl, hydroxyl, and amino groups) in controlled proportions. This changes the evaporation kinetics and film formation dynamics of the waterborne system, extending open time while maintaining the environmental benefits of water-based formulation
Solution Approach 2:
The multistage polymerization process performs preliminary structural organization of the polymer chains during synthesis, creating a predetermined architecture with distributed functional groups. This preliminary structuring ensures that the polymer provides extended open time and appropriate water resistance from the outset, eliminating the need for post-formulation additives that would compromise performance
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 aqueous coating composition achieves an extended open time of 11 minutes or more and a repair time of 16 minutes or more, while maintaining a high level of water resistance, as measured under specific conditions.
Implementation Method 1
a multistage free-radical polymerization process comprises: (i) preparing a first polymer in an aqueous medium by a free-radical polymerization
Data Source
AI summary
An aqueous dispersion of a multistage polymer, an aqueous coating composition having an extended open time and capable of providing coatings with good water resistance, and a process of preparing the coatings.