Multiple Hydrophobic Polymer Coatings for Durable Dirt Mitigation

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Solution Overview

Problem

Existing easy-to-clean (E2C) coatings suffer from incompatibility between hydrophilic film-forming binders and hydrophobic additives, leading to stratification and reduced durability, resulting in ineffective dirt mitigation and increased haze.

Innovation Solution

A curable film-forming composition comprising two distinct acrylic polymers, where the first polymer is distributed throughout the coating layer and the second polymer is concentrated at the surface, using a curing agent to create a multi-layered coating with enhanced hydrophobicity, ensuring uniform distribution and extended dirt mitigation properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If hydrophobic acrylates are used as additives to create easy-to-clean coatings, then dirt mitigation properties are improved, but stratification occurs and haze increases due to incompatibility with hydrophilic binders

Engineering Contradiction:
Improvedirt mitigation propertiesVSAvoidcoating uniformity
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The invention changes the fundamental parameter of binder hydrophobicity from hydrophilic to hydrophobic, enabling compatibility with hydrophobic acrylate additives. This parameter change resolves the stratification and haze issues while maintaining effective dirt mitigation properties throughout the coating matrix.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention creates a composite coating system combining hydrophobic polymer binders with hydrophobic acrylate additives. This composite approach ensures compatibility between components, preventing stratification while achieving synergistic dirt mitigation effects throughout the coating layer.

Inventive Principle:
Principle #40Composite materials

2Ease of operation

If hydrophobic additives are incorporated into coatings, then easy cleaning properties are improved, but durability decreases due to poor retention over time

Engineering Contradiction:
Improveeasy cleaning propertiesVSAvoidcoating durability
Core Design Contradiction:
Ease of operationVSDuration of action of stationary object

Solution Approach 1:

The invention changes the binder hydrophobicity parameter to match the additives, creating a compatible matrix that prevents phase separation and maintains uniform distribution of hydrophobic components over time, thereby improving durability while retaining easy cleaning properties.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The continuous hydrophobic matrix ensures sustained dirt mitigation properties over time by maintaining uniform distribution and preventing degradation or separation of the hydrophobic components, extending the coating's effective service life.

Inventive Principle:
Principle #20Continuity of useful action

3Reliability

If hydrophobic additives are used in coatings, then dirt mitigation is improved, but haze increases due to irregular distribution

Engineering Contradiction:
Improvedirt mitigationVSAvoidhaze
Core Design Contradiction:
ReliabilityVSIllumination intensity

Solution Approach 1:

The invention changes the binder's hydrophobicity parameter to match the additives, ensuring compatible interactions that promote uniform distribution throughout the coating. This eliminates the irregular clustering that causes light scattering and haze while maintaining effective dirt mitigation.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention achieves homogeneous distribution of hydrophobic components throughout the coating matrix by using compatible hydrophobic binders. This uniform distribution prevents light scattering centers from forming, thereby reducing haze while maintaining consistent dirt mitigation properties across the coating surface.

Inventive Principle:
Principle #33Homogeneity

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 multi-layered coating provides improved durability and extended dirt mitigation properties, maintaining water contact angle retention and resisting abrasion, effectively preventing dirt build-up on substrates.

Implementation Method 1

the second film-forming polymer (b) is more hydrophobic than the first film-forming polymer (a), and wherein upon application of the curable film-forming composition to a substrate to form a coating layer, the first film-forming polymer (a) is distributed throughout the coating layer, and a concentration of the second film-forming polymer (b) is greater within a surface region of the coating layer than a concentration of the second film-forming polymer (b) within a bulk region of the coating layer

Methodology Applied
Scientific EffectHydrophobicity-driven phase separation:

Implementation Method 2

a curing agent (c) comprising functional groups reactive with the reactive functional groups in (a)

Methodology Applied
Scientific EffectChemical reaction: Chemical Bonding

Data Source

PatentEP3824003B1Curable film-forming compositions prepared from multiple hydrophobic polymers and method of mitigating dirt build-up on a substrate
Publication Date: 2025.09.03 PPG INDUSTRIES OHIO INC
  • EP3824003B1 patent drawingFigure 1
  • EP3824003B1 patent drawingFigure 2
  • EP3824003B1 patent drawingFigure 3

AI summary

The present invention is directed to curable film-forming compositions comprising a first film-forming polymer prepared from at least one hydrophobic monomer, a second film-forming polymer prepared from at least one hydrophobic monomer, and a curing agent. Upon application of the curable film-forming composition to a substrate to form a coating layer, the first film-forming polymer is distributed throughout the coating layer, and the concentration of the second film-forming polymer is greater at the surface of the coating layer than the concentration of the second film-forming polymer within the bulk of the coating layer. The invention is additionally drawn to substrates coated with the curable film-forming composition. The present invention is also drawn to methods of mitigating dirt build-up on a substrate, comprising applying to at least a portion of the substrate the curable film-forming composition described above and at least partially curing the curable film-forming composition.