Water-Based Acrylic Uthane Coating Adhesion

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Solution Overview

Problem

Current water-based exterior coatings fail to adhere effectively to polyurethane foam boards, leading to the use of solvent-based coatings, which pose safety and environmental concerns.

Innovation Solution

A two-component water-based acrylic urethane coating composition comprising a hydroxyl functional acrylic polymer emulsion and a water-emulsifiable isocyanate, providing excellent adhesion and durability while minimizing VOC content and allowing for aesthetically pleasing finishes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If water-based exterior coatings are used to coat polyurethane foam boards, then safety and environmental concerns are minimized, but adhesion to the polyurethane foam surface is insufficient

Engineering Contradiction:
Improvesafety and environmental hazardsVSAvoidadhesion to polyurethane foam surface
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The invention changes the chemical parameters of the water-based coating by incorporating isocyanate crosslinking agents and specific adhesion promoters, transforming it from a simple emulsion to a chemically reactive system that can form strong covalent bonds with the polyurethane foam surface, thereby achieving both safety benefits and reliable adhesion

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The coating composition is formulated as a composite system combining water-based acrylic polymers with isocyanate crosslinkers and adhesion promoters, creating a multi-functional coating that integrates the safety benefits of water-based systems with the adhesion properties traditionally associated with solvent-based systems

Inventive Principle:
Principle #40Composite materials

2Reliability

If solvent-based coatings are used to coat polyurethane foam boards, then adhesion to the surface is improved, but safety and environmental concerns increase

Engineering Contradiction:
Improveadhesion to polyurethane foam surfaceVSAvoidsafety and environmental hazards
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The invention fundamentally changes the solvent parameter from organic solvents to water as the continuous phase, while compensating for the loss of adhesion by introducing crosslinking chemistry and specific adhesion promoters, thereby eliminating VOC emissions while maintaining coating performance

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention replaces the physical adhesion mechanism of solvent-based coatings with chemical adhesion through isocyanate crosslinking, substituting a mechanical/physical bonding system with a chemical bonding system that achieves stronger and more durable attachment to the polyurethane foam surface

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Device complexity

If polyurethane foam boards are left uncoated, then manufacturing complexity is reduced, but UV degradation occurs over time

Engineering Contradiction:
Improvecoating system complexityVSAvoidresistance to UV degradation
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The invention modifies the chemical composition of the coating to include UV stabilizers and pigments that provide inherent UV resistance, changing the protective parameters of the coating system to specifically address photodegradation while maintaining a relatively simple two-component application system

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The coating composition is designed to perform multiple functions simultaneously: providing adhesion to polyurethane foam, offering water resistance, preventing UV degradation, and enabling aesthetic finishes, thereby consolidating multiple protective functions into a single coating system that reduces overall system complexity

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 strong adhesion to polyurethane foam boards, offering water resistance, UV protection, and the ability to be recoated with standard exterior paints, while reducing safety and environmental hazards associated with solvent-based coatings.

Implementation Method 1

a two-component water-based acrylic urethane coating composition comprising a first component and a second component, wherein said first component comprises a hydroxyl functional acrylic polymer emulsion, and wherein said second component comprises a water-emulsifiable isocyanate

Methodology Applied
Scientific EffectChemical Bonding: Chemical Bonding

Data Source

PatentUS11999867B2Coating composition and coated substrate
Publication Date: 2024.06.04 SIKA TECH AG

AI summary

A two-component water-based coating composition that exhibits good adherence to the surface of substrates such as polyurethane foam boards. The two-component water-based coating composition is based on acrylic urethane chemistry. Coated substrates, including polyurethane foam boards coated with the two-component water-based acrylic urethane coating composition, wall cladding systems, and building walls incorporating the coated polyurethane foam boards are also disclosed. The coated polyurethane foam boards are water resistant, mold resistant, mildew resistant, UV radiation resistant, lightweight and thermally insulative.