Glycidyl Ether Alkoxylate Block Copolymers for Waterborne Coating Open Time
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Solution Overview
Problem
Current waterborne coating formulations have a limited open time, typically ranging from 3 to 5 minutes, which is insufficient for reworking without leaving brush marks, and existing additives that increase open time compromise other paint properties such as film adhesive strength and resistance.
Innovation Solution
A glycidyl ether alkoxylate block copolymer with a specific chemical structure, where Ar1 and Ar2 are phenyl or naphthyl groups, and R1 can be H or C1-C6 alkyl, is used as an open time additive, prepared by reacting an aryl alcohol with an aryl glycidyl ether and alkylene oxide, offering improved open time without degrading other paint properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If existing open time additives are used in waterborne formulations, then open time is increased, but film adhesive strength and cohesive strength are degraded
Solution Approach 1:
The patent changes the chemical structure parameters of the additive by using specific glycidyl ether alkoxylate block copolymers with defined molecular weights (5,000-50,000) and specific compositions (epoxy equivalent weight 200-1000, alkoxylate degree 1-20). This structural parameter optimization allows achieving extended open time (5-30 minutes) while maintaining film adhesive and cohesive strengths above 5 ft-lb, resolving the contradiction between open time extension and strength preservation.
Solution Approach 2:
The invention employs composite molecular architecture combining glycidyl ether blocks with alkoxylate blocks to create an amphiphilic copolymer structure. This composite material design enables the additive to simultaneously provide extended open time through surfactant properties while maintaining coating strength through controlled hydrophobic interactions, avoiding the strength degradation caused by conventional single-function additives.
2Duration of action of moving object
If high concentrations of surfactant are used to increase open time, then open time is marginally increased, but other coating properties are degraded
Solution Approach 1:
The patent optimizes the molecular weight parameter of the additive to 5,000-50,000, which controls the surfactant efficiency and micelle formation behavior. This parameter optimization enables effective open time extension at low concentrations (0.1-5% by weight) while preventing degradation of coating properties such as hardness, block resistance, and blister resistance that would occur at higher surfactant concentrations.
Solution Approach 2:
The invention creates a molecular structure that copies the essential surfactant functionality needed for open time extension but with optimized hydrophobic and hydrophilic block ratios. This allows achieving the desired open time effect (5-30 minutes) at low concentrations (0.1-5%) without the harmful side effects associated with high surfactant loading, preserving all other coating properties.
3Object-affected harmful factors
If waterborne formulations are used to reduce VOC, then environmental compliance is improved, but open time is reduced to 3-5 minutes
Solution Approach 1:
The patent introduces a specifically designed glycidyl ether alkoxylate block copolymer with molecular weight 5,000-50,000 and controlled composition parameters into waterborne formulations. This additive extends open time from the typical 3-5 minutes to 5-30 minutes while maintaining the waterborne (low/zero VOC) formulation structure, thus achieving both environmental compliance and adequate open time for brush rework.
Solution Approach 2:
The glycidyl ether alkoxylate block copolymer acts as an intermediary substance in waterborne formulations, mediating between the water-based continuous phase and the polymer particles. This intermediary provides extended open time (5-30 minutes) through controlled micelle formation and interfacial activity without requiring organic solvents or coalescents, enabling brush rework in environmentally compliant formulations.
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 glycidyl ether alkoxylate block copolymer significantly increases open time to 11-18 minutes while maintaining or improving other paint properties like film adhesive strength and resistance, even at lower concentrations compared to existing additives.
Implementation Method 1
the use of such high concentrations of a surfactant to achieve a marginal increase in open time
Data Source
AI summary
The present invention relates to a compound having the following structure I: where Ar1, Ar2; R1, m, and n are defined herein. The compound of the present invention is useful as an open time additive in waterborne coatings compositions, particularly waterborne paint compositions.