Silane-Modified Polyisocyanate Coatings for Soiling Resistance

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Current coating compositions for automotive finishes lack improved soiling resistance and self-cleaning properties, especially after weathering exposure, while maintaining good appearance and performance.

Innovation Solution

A nonaqueous coating composition comprising a hydroxyl group-containing compound, an isocyanate group-containing compound with free or blocked isocyanate groups, a catalyst for silane crosslinking, and an alkoxysilyl-functional siloxane, which provides excellent soiling resistance and self-cleaning properties without compromising appearance or weathering stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional polyurethane coating compositions are used, then good weathering resistance and scratch resistance are achieved, but soiling resistance and self-cleaning properties are insufficient

Engineering Contradiction:

Improvesoiling resistanceVSAvoidcoating composition complexity

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent uses composite materials by combining polyurethane resin with silane-modified polyisocyanate and alkoxysilyl-functional siloxane. This composite approach integrates the weathering resistance of polyurethane with the soiling resistance of silane crosslinked networks, achieving both properties simultaneously without significantly complicating the manufacturing process

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent changes the chemical parameters of the coating composition by introducing silane groups and catalysts that enable crosslinking reactions. This parameter change transforms the coating from a simple polyurethane system to a crosslinked network structure with enhanced soiling resistance while maintaining weathering stability

Inventive Principle:

Principle #35Parameter changes

2Reliability

If silane crosslinking is introduced to improve soiling resistance, then self-cleaning properties improve, but coating composition complexity increases

Engineering Contradiction:

Improveself-cleaning propertiesVSAvoidcoating composition structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the silane crosslinking function with the existing polyisocyanate component by using silane-modified polyisocyanate. This combining approach integrates multiple functions (crosslinking, soiling resistance, and compatibility with polyurethane resin) into a single component, reducing overall formulation complexity while achieving self-cleaning properties

Inventive Principle:

Principle #5Merging (Combining)

3Reliability

If fluorine-containing additives are used to improve water repellency and cleaning properties, then soiling resistance improves, but appearance quality deteriorates

Engineering Contradiction:

Improvewater repellencyVSAvoidappearance quality

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The patent replaces expensive fluorine-containing additives with a more economical silane-based system. The silane crosslinked network provides comparable water repellency and soiling resistance without the appearance defects associated with fluorine additives, achieving a cost-effective solution with maintained appearance quality

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent changes the chemical composition parameters by using silane groups instead of fluorine-containing compounds. This parameter substitution maintains the hydrophobic effect and soiling resistance while eliminating the appearance deterioration caused by fluorine additives, achieving both functional and aesthetic requirements

Inventive Principle:

Principle #35Parameter changes

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 coating composition achieves superior soiling resistance and self-cleaning properties, retaining a good appearance and haze resistance even after weathering exposure, with a surface energy below 25 mJ/m² and minimal change in lightness values, indicating effective dirt repulsion and cleaning performance.

Implementation Method 1

comprising at least one catalyst for the crosslinking of the silane groups

Methodology Applied

Scientific EffectSilane crosslinking: Chemical Bonding

Implementation Method 2

at least one isocyanate group-containing compound having free or blocked isocyanate and silane groups

Methodology Applied

Scientific EffectCondensation reaction: Chemical Bonding

Implementation Method 3

excellent soiling resistance and self-cleaning properties without compromising appearance or weathering stability

Methodology Applied

Scientific EffectHydrophobic effect: Hydrophobe

Implementation Method 4

with a surface energy below 25 mJ/m²

Methodology Applied

Scientific EffectSurface energy reduction: Surface Tension

Data Source

PatentUS11597794B2Coating compositions and coatings produced therefrom with improved soiling resistance and (self-)cleaning properties and use thereof

Publication Date: 2023.03.07 BASF COATINGS GMBH

AI summary

Coating compositions and coatings with improved soiling resistance and (self-)cleaning properties are disclosed. The coating compositions and coatings may be nonaqueous coating compositions and may include at least one hydroxyl group-containing compound, at least one isocyanate group-containing compound having free or blocked isocyanate and silane groups, at least one catalyst for the crosslinking of the silane groups, and at least one alkoxysilyl-functional siloxane.