Soft-Touch Aqueous Coating via Polyurethane-Acrylic Hybrid Particles
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Solution Overview
Problem
Existing one-component aqueous coating compositions fail to achieve a balance between soft-touch properties and mechanical/barrier properties such as block resistance and transparency, often resulting in poor performance in resistance to water, ethanol, detergent, and coffee due to limitations in polyisocyanate crosslinkers and particle size.
Innovation Solution
Aqueous coating composition comprising urethane-acrylic hybrids with dispersed polyurethane-vinyl polymer hybrid particles, where the polyurethane and vinyl polymer are present in a specific weight ratio, and include specific components like organic difunctional isocyanates, isocyanate-reactive compounds, and active-hydrogen chain extenders, allowing for improved mechanical and barrier properties without the need for additional crosslinking agents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If one-component aqueous coating compositions use polyisocyanate crosslinkers to enhance mechanical properties, then block resistance improves, but transparency deteriorates and handling becomes complex due to short pot life and CO2 bubble formation
Solution Approach 1:
The patent removes polyisocyanate crosslinkers from the formulation entirely, extracting the harmful element that causes CO2 bubble formation and short pot life. The soft-touch coating achieves its properties through a different mechanism that does not require crosslinking agents, thereby eliminating the associated handling complexities while maintaining block resistance.
Solution Approach 2:
The coating formulation uses a stable, non-crosslinking chemistry that allows for long pot life and extended handling time. The composition remains usable for prolonged periods without degradation, replacing the short-lived crosslinked systems with a durable, handleable formulation that maintains performance throughout the application process.
2Strength
If one-component aqueous coating compositions use polyisocyanate crosslinkers to enhance mechanical properties, then block resistance improves, but transparency deteriorates
Solution Approach 1:
The patent removes polyisocyanate crosslinkers from the formulation entirely, extracting the harmful element that causes CO2 bubble formation and short pot life. The soft-touch coating achieves its properties through a different mechanism that does not require crosslinking agents, thereby eliminating the associated handling complexities while maintaining block resistance.
Solution Approach 2:
The coating formulation uses a stable, non-crosslinking chemistry that allows for long pot life and extended handling time. The composition remains usable for prolonged periods without degradation, replacing the short-lived crosslinked systems with a durable, handleable formulation that maintains performance throughout the application process.
3Ease of operation
If the coating provides soft-touch sensation, then haptic quality improves, but barrier properties like water and coffee resistance deteriorate
Solution Approach 1:
The patent employs a composite polymer structure combining polyurethane and acrylic components in a hybrid dispersion. This composite material integrates the soft-touch characteristics of polyurethane with the barrier properties of acrylic, achieving both haptic quality and resistance to water, coffee, and other liquids simultaneously through the synergistic combination of polymer phases.
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 provides a soft-touch coating with enhanced block resistance, water resistance, ethanol resistance, and coffee resistance while maintaining good transparency, extending pot-life and avoiding issues like carbon dioxide bubble formation and short handling times.
Implementation Method 1
dispersed polyurethane-vinyl polymer hybrid particles obtained by free-radical polymerization of at least one vinyl monomer in the presence of a polyurethane
Implementation Method 2
drying the aqueous coating composition by evaporation of volatiles to obtain a coating
Data Source
AI summary
The present invention relates to an aqueous coating composition comprising dispersed polymer particles, wherein (i) the dispersed polymer particles are polyurethane-vinyl polymer hybrid particles obtained by free-radical polymerization of at least one vinyl monomer in the presence of a polyurethane, (ii) the polyurethane and the vinyl polymer in the hybrid particles are present in a weight ratio of polyurethane to vinyl polymer ranging from 1:1 to 20:1, (iii) the polyurethane is the reaction product of at least the following components: (a) from 5 to 40 wt.% of at least one organic difunctional isocyanate, (b) from 0.5 to 4 wt.% of an isocyanate-reactive compound containing ionic or potentially ionic water-dispersing groups having a molecular weight of from 100 to 500 g/mol, (c) from 40 to 80 wt.% of at least one diol having a molecular weight from 500 to 5000, (d) from 0 to 10 wt.% of at least one active-hydrogen chain extending compound with a functionality of at least 2 (other than water), (e)from 0 to10 wt.% of at least one diol having a molecular weight below 500 g/mol, where the amounts of (a), (b), (c), (d) and (e) are given relative to the total amount of components used to prepare the polyurethane from which the building blocks of the polyurethane are emanated, and where the isocyanate and hydroxy groups on the components used to prepare the polyurethane are present in a respective mole ratio (NCO to OH) in the range of from 0.8:1 to 5:1, preferably from 1.05:1 to 5:1 and even more preferably from 1.1:1 to 3.5:1.