Waterborne Soft-Feel Coating Composition
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Solution Overview
Problem
Existing soft-feel coatings for automobile interiors face a challenge in achieving a balance between chemical and mechanical resistance and haptic properties, as improving one aspect often deteriorates the other.
Innovation Solution
A waterborne coating composition comprising at least two different polyurethanes, one with hydroxyl groups and a polyisocyanate, along with a compound having a molecular weight of at most 1,000 and at least two isocyanate-reactive groups, excluding poly(ethylene glycol), to enhance chemical and mechanical resistance while maintaining soft-feel properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the crosslink density and hardness of the coating are increased to improve chemical and mechanical resistance, then the resistance properties are improved, but the soft-feel properties deteriorate
Solution Approach 1:
The patent changes the chemical composition parameters by introducing a specific compound with molecular weight of at most 1,000 and at least two isocyanate-reactive groups (excluding poly(ethylene glycol)). This parameter change enables the coating to achieve both high crosslink density for resistance and maintained softness, resolving the contradiction between durability and haptic properties
Solution Approach 2:
The patent creates a composite coating system combining at least two different polyurethanes (one with hydroxyl groups) and a polyisocyanate crosslinker, plus the specific low-molecular-weight compound. This composite approach allows the coating to simultaneously achieve mechanical strength, chemical resistance, and soft-feel properties that cannot be obtained with single-component systems
2Reliability
If a higher proportion of crosslinker is used to improve chemical and mechanical resistance, then the resistance is improved, but the soft-feel properties deteriorate
Solution Approach 1:
The patent introduces a specific parameter change by using a compound with molecular weight of at most 1,000 and at least two isocyanate-reactive groups. This parameter enables effective crosslinking at lower crosslinker concentrations while maintaining soft-feel properties, as the low-molecular-weight compound provides efficient crosslinking sites without excessive rigidity
3Reliability
If binders with higher hardness and higher proportion of crosslinkable functional groups are employed to improve resistance, then the chemical and mechanical resistance is improved, but the soft-feel properties deteriorate
Solution Approach 1:
The patent specifies using at least two different polyurethanes where one contains hydroxyl groups, combined with a polyisocyanate crosslinker and the low-molecular-weight compound. This parameter specification allows the binder system to achieve adequate crosslinking for resistance while maintaining the softness required for haptic comfort in automotive interior applications
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 an improved balance of chemical and mechanical resistance and soft-feel properties, allowing for effective suntan lotion resistance and reduced organic solvent requirements, with coatings exhibiting better mar and scratch resistance without compromising soft-feel sensations.
Implementation Method 1
a water borne coating composition comprising at least two different polyurethanes of which at least one polyurethane comprises hydroxyl groups and a polyisocyanate, wherein the composition further comprises a compound, other than poly(ethylene glycol), having a molecular weight of at most 1,000 and having at least two isocyanate-reactive groups
Implementation Method 2
Improvement of the chemical and mechanical resistance of soft-feel coatings, at a given layer thickness, can be achieved by increasing the crosslink density
Data Source
AI summary
The invention relates to a water borne coating composition comprising a polyurethane and a polyisocyanate, wherein the composition further comprises a compound having a molecular weight of at most 1,000 and having at least two isocyanate-reactive groups, with the proviso that said compound having a molecular weight of at most 1,000 and having at least two isocyanate-reactive groups is not a poly(ethylene glycol), and that the polyurethane differs from the material formed by reaction of the polyisocyanate and the compound having a molecular weight of at most 1,000 and having at least two isocyanate-reactive groups.