Silane-Hardened Aqueous Basecoat for Low-Temperature Adhesion

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Solution Overview

Problem

Existing coating systems face challenges in achieving low-temperature curing without using isocyanates or aminoplast crosslinkers, while maintaining high pot life and steam jet adhesion, particularly in automotive applications, and they often compromise optical and coloristic properties.

Innovation Solution

An aqueous basecoat composition using a silane-based compound with low isocyanate content, combined with a binder and pigment, which enhances steam jet adhesion when paired with ambient curing clearcoats, and a mixer kit for preparing these compositions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If polyisocyanate crosslinkers are used in coating systems, then crosslinking and adhesion properties are improved, but environmental and health requirements are violated and economic efficiency is reduced

Engineering Contradiction:

Improveadhesion propertiesVSAvoidenvironmental and health harm

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent removes polyisocyanate crosslinkers from the coating system and replaces them with silane-based crosslinkers that cure at low temperatures. This extraction of the harmful component (polyisocyanate) eliminates the environmental and health hazards while maintaining the essential crosslinking function through an alternative chemical mechanism involving silane compounds and water.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent changes the curing temperature parameter from high temperature to low temperature (ambient or mildly elevated temperatures). This parameter change enables the use of alternative crosslinking chemistry (silane-based instead of polyisocyanate-based) that is environmentally benign and economically efficient, while still achieving effective crosslinking and adhesion.

Inventive Principle:

Principle #35Parameter changes

2Productivity

If ambient curing clearcoats are used with low temperature-curing basecoat systems, then economic efficiency is improved, but steam jet adhesion becomes weak and OEM minimum requirements are not met

Engineering Contradiction:

Improveeconomic efficiencyVSAvoidsteam jet adhesion

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent introduces silane-based crosslinking agents as an intermediary substance that mediates between the basecoat and clearcoat layers. These silane crosslinkers form strong chemical bonds with both layers, creating a robust interlayer adhesion that satisfies OEM requirements while enabling low-temperature curing that improves economic efficiency.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If polyisocyanate hardeners are added to basecoat compositions to improve adhesion, then steam jet adhesion is improved, but environmental and health requirements are violated

Engineering Contradiction:

Improvesteam jet adhesionVSAvoidenvironmental and health harm

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent converts the harmful polyisocyanate crosslinking mechanism into a beneficial silane-based crosslinking mechanism. The silane crosslinkers provide the necessary adhesion enhancement without the harmful effects of polyisocyanates, turning a harmful chemical process into an environmentally friendly one that achieves the same functional goals.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

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 steam jet adhesion, long pot life, and maintains optical and coloristic properties, suitable for automotive OEM and refinish coatings, without the use of isocyanates.

Implementation Method 1

the condensation reaction of alkoxy silanes can be catalyzed tin-free and curing at ambient conditions is achievable

Methodology Applied

Scientific EffectCondensation reaction: Condensation

Implementation Method 2

comprising a specific silane-based additive as hardener/self-crosslinking material to improve the adhesion of the basecoat to the under- and overlying coating layers, as well as the cohesion property of the basecoat itself

Methodology Applied

Scientific EffectSelf-crosslinking: Chemical Bonding

Data Source

PatentUS12612524B2Aqueous basecoat composition comprising a silane-based additive and having improved adhesion properties and multilayer coatings produced from said basecoat compositions

Publication Date: 2026.04.28 BASF COATINGS GMBH

AI summary

Described herein is an aqueous basecoat composition including a silane-based additive as hardener/self-crosslinking material to improve adhesion of the basecoat to the under- and overlying coating layers, as well as the cohesion property of the basecoat itself. Also described herein is a mixer system for preparing an aqueous refinish basecoat composition including at least one base color component, at least one pigment-free component, at least one hardening component including the silane-based additive and optionally at least one rheology module as well as a method to prepare an aqueous basecoat composition from said mixer system. Further, described herein is a method of coating a substrate with the basecoat composition and a clearcoat composition and jointly curing the basecoat and clearcoat composition as well as to a coated substrate obtained from the method. Finally, described herein is a method of using the silane-based compound as hardening additive in aqueous basecoat compositions.