Nitrofunctional Polyurethane Binders for Aqueous Coatings
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Solution Overview
Problem
Aqueous-based paints and coatings lack the chemical and physical protection, as well as adhesion properties compared to their alkyd-based counterparts, necessitating improved binder compositions for enhanced performance.
Innovation Solution
The use of nitrofunctional polyurethane binders, synthesized by reacting nitroalcohol, polyol, and polyisocyanate compounds, which are then dispersed in water, providing improved hardness and adhesion in aqueous-based paint formulations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If aqueous-based paints and coatings are used instead of alkyd-based paints, then VOC content is reduced and environmental friendliness is improved, but chemical resistance, physical protection, and adhesion properties deteriorate
Solution Approach 1:
The invention modifies the chemical structure of polyurethane binders by introducing nitro groups at specific positions (alpha, beta, or gamma positions relative to hydroxyl groups). This structural parameter change enhances the crosslinking density and chemical resistance of the polymer network, allowing aqueous-based coatings to achieve chemical resistance and adhesion properties comparable to or exceeding traditional alkyd-based systems while maintaining low VOC content
Solution Approach 2:
The invention creates composite polyurethane structures combining conventional polyol segments with nitrofunctional segments. This composite approach integrates the benefits of both traditional polyurethane flexibility and nitro-group-enhanced crosslinking, resulting in a binder that provides superior chemical resistance, hardness, and adhesion in aqueous-based formulations
2Ease of manufacture
If traditional polyurethane binders are used in aqueous-based coatings, then ease of manufacture and low VOC are achieved, but hardness development and chemical resistance are insufficient
Solution Approach 1:
The invention introduces nitro groups at specific positions (alpha, beta, or gamma) in the polyurethane chain, which fundamentally changes the crosslinking behavior and curing characteristics of the binder. This parameter change enables faster and more complete crosslinking, resulting in superior hardness development and chemical resistance while maintaining the aqueous-based formulation advantages
3Reliability
If nitrofunctional polyurethane binders are used to improve hardness and chemical resistance, then protection properties are enhanced, but binder composition complexity increases
Solution Approach 1:
The invention achieves enhanced protection properties by modifying the polyol component with nitro groups rather than changing the entire binder system. This targeted parameter change in the polyol structure simplifies the overall composition compared to developing entirely new polymer systems, as it leverages existing polyurethane technology with a specific structural modification that delivers superior chemical resistance and hardness
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 nitrofunctional polyurethane binders exhibit enhanced hardness development and chemical resistance, with coatings demonstrating improved durability and protection, such as Konig hardness of at least 20 seconds after 1 day and up to 100 seconds after 7 days of drying.
Implementation Method 1
the polyurethane polymer is prepared by reacting a nitroalcohol compound, a polyol compound, a polyisocyanate compound
Implementation Method 2
the nitrofunctional polyurethane binders exhibit enhanced hardness development and chemical resistance, with coatings demonstrating improved durability and protection
Data Source
AI summary
Provided is a binder composition and its use in aqueous based paints and coatings and other applications. The binder composition comprises: a polyurethane dispersion containing water and a polyurethane polymer, wherein the polyurethane polymer is prepared by reacting a nitroalcohol compound, a polyol compound, a polyisocyanate compound, and optionally chain extenders, wherein the nitroalcohol compound is of formula I, wherein R, R1, and Z are as defined herein.