Glycol Ether Amines for Stable Low-Odor Polyurethane Coatings
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Solution Overview
Problem
Existing aqueous two-component polyurethane coating compositions lack sufficient pH and pigment dispersion stability while maintaining acceptable dry-film properties, and conventional pH neutralizers like ammonia have strong odors unsuitable for low-odor coatings.
Innovation Solution
Incorporating an aqueous acrylic or vinyl polymer dispersion with hydroxyl groups or polyols, pigments, extenders/colorants, and glycol ether amines, along with a water dispersible polyisocyanate curing agent, to form a curable coating composition that enhances pH stability and pigment dispersion without affecting dry-film properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional pH neutralizers like ammonia are used, then pH adjustment is achieved, but strong odors are generated making them unsuitable for low-odor coatings
Solution Approach 1:
The patent changes the chemical structure parameter of the neutralizer from conventional ammonia or simple organic amines to glycol ether amines with specific molecular structures (formula I). This structural modification maintains pH neutralization capability while significantly reducing odor, thus resolving the contradiction between pH adjustment effectiveness and odor control.
Solution Approach 2:
The invention uses composite molecular structure of glycol ether amines that combine the pH-neutralizing amine group with the odor-reducing glycol ether moiety. This composite structure integrates the beneficial properties of both functional groups, achieving effective pH control with minimal odor impact.
2Loss of substance
If aqueous two-component polyurethane coating compositions are used to reduce VOC levels, then volatile organic content is reduced, but pH and pigment dispersion stability are insufficient
Solution Approach 1:
The patent modifies the chemical composition parameters of the aqueous system by introducing glycol ether amines with specific molecular weights and structures. This changes the solution chemistry to provide adequate pH buffering and pigment dispersion stability while maintaining the low-VOC advantage of aqueous formulations.
Solution Approach 2:
The glycol ether amine acts as an intermediary substance that mediates between the aqueous polymer dispersion and pigment particles. It provides steric and electrostatic stabilization to pigment dispersions while also serving as a pH buffer, thus resolving the stability issues in aqueous polyurethane systems.
3Object-affected harmful factors
If organic amines like 2-amino-2-methyl-1-propanol are used as pH neutralizers, then low odor and multifunctional benefits are achieved, but pigment dispersion and pH stability are still insufficient for industrial coatings
Solution Approach 1:
The patent optimizes the molecular parameters of the amine neutralizer by selecting glycol ether amines with specific chain lengths (m=1-6) and alkyl groups (R1=C1-C6, R2/R3=CH3 or CH2-CH3). This parameter optimization enhances both pH stability and pigment dispersion capabilities while maintaining low odor characteristics.
Solution Approach 2:
The glycol ether amine structure provides multiple functions simultaneously: pH neutralization, pigment dispersion stabilization, and odor control. The hydrophilic glycol ether portion aids dispersion while the amine group provides pH control, creating a universal additive that addresses multiple requirements in industrial coating 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 composition achieves improved pH stability and pigment dispersion, forming polyurethane coatings with acceptable appearance and film properties, suitable for industrial and architectural coatings, while minimizing volatile organic compounds.
Implementation Method 1
one or more glycol ether amines having the following formula I... provide enhanced pH and pigment dispersion stability
Implementation Method 2
provide enhanced pH and pigment dispersion stability
Implementation Method 3
aqueous two-component polyurethane coating compositions comprising water-dispersible isocyanates and emulsion polymers... react together to produce the polyurethane
Data Source
AI summary
The present invention provides aqueous compositions comprising (i) an aqueous acrylic or vinyl polymer dispersion wherein the polymer comprises an average of two or more hydroxyl groups or contains a polyol, (ii) one or more pigments, extenders or colorants, or their combination, and, (iii) one or more glycol ether amines having the following formula I: wherein R1 is a C1 to C6 alkyl group, or, preferably, a C3 to C4 alkyl group, R2 and R3 are, independently, CH3 or CH2—CH3; and, m is 1 to 6, or, preferably, from 1 to 2. The aqueous composition may further comprise a water dispersible polyisocyanate curing agent, thereby forming a curable aqueous coating composition that forms a polyurethane coating or film.