Fluoropolymer-Aliphatic Polyester Coatings for Weathering Stability

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Solution Overview

Problem

Existing coatings for outdoor metal surfaces fail to provide sustained corrosion control, aesthetic appeal, and weather resistance, with limitations in gloss range, surface hardness, and cost-effectiveness, particularly due to the instability of aromatic polyester components under solar radiation and the high cost of fluoroethylene-vinyl ether-based coatings.

Innovation Solution

A formulation combining hydroxy-functional fluoropolymers with aliphatic or cycloaliphatic polyesters, crosslinkers, UV absorbers, and UV stabilizers, which allows for high-gloss, medium-gloss, or matte finishes, offering excellent corrosion resistance, weathering stability, and cost-effectiveness by forming a durable, flexible, and chemically resistant coating.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Shape

If aromatic polyester formulations are used to achieve good initial surface coating properties, then surface quality is improved, but weathering stability deteriorates due to instability under solar radiation

Engineering Contradiction:
Improvesurface qualityVSAvoidweathering stability
Core Design Contradiction:
ShapeVSStability of the object's composition

Solution Approach 1:

The invention extracts and removes the harmful aromatic structural units from the polyester formulation, replacing them with aliphatic or cycloaliphatic structural units that do not degrade under UV radiation, thereby maintaining weathering stability while preserving surface quality

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention changes the chemical composition parameters of the polyester by specifying that it must be based on aliphatic or cycloaliphatic structural units rather than aromatic units, fundamentally altering the photochemical stability of the coating system

Inventive Principle:
Principle #35Parameter changes

2Reliability

If fluoroethylene-vinyl ether-based coating formulations are used to achieve high corrosion resistance and weathering stability, then protection performance is improved, but cost increases significantly

Engineering Contradiction:
Improvecorrosion resistanceVSAvoidcost-effectiveness
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The invention creates a composite coating system combining fluoropolymer resin (for corrosion and weathering resistance) with aliphatic/cycloaliphatic polyester (for aesthetic properties and flexibility), achieving high performance through material synergy rather than relying on expensive fluoroethylene-vinyl ether formulations

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The invention merges the protective functions of fluoropolymers with the aesthetic and flexible properties of aliphatic polyesters in a single coating formulation, consolidating multiple functions into one cost-effective system

Inventive Principle:
Principle #5Merging (Combining)

3Shape

If polyester components with aromatic structural units are used to achieve good initial surface properties, then surface finish is improved, but aesthetic durability worsens under prolonged solar exposure

Engineering Contradiction:
Improvesurface finishVSAvoidaesthetic durability
Core Design Contradiction:
ShapeVSDuration of action of stationary object

Solution Approach 1:

The invention extracts the photo-unstable aromatic units from the polyester structure and replaces them with photo-stable aliphatic or cycloaliphatic units, eliminating the cause of yellowing and degradation while maintaining the desired surface finish properties

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention replaces expensive, photo-unstable aromatic polyester components with more cost-effective, photo-stable aliphatic polyester components that provide equivalent or superior long-term aesthetic durability

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

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 provides long-lasting protection against corrosion, weathering, and mechanical wear, maintaining surface quality and aesthetic appeal, even in harsh environments, with improved flexibility and chemical resistance, and a favorable cost-benefit ratio.

Implementation Method 1

a crosslinkable polyester component and a fluoropolymer in a 1:1 ratio, by weight

Methodology Applied
Scientific EffectCrosslinking: Chemical Bonding

Implementation Method 2

UV absorbers and UV stabilizers

Methodology Applied
Scientific EffectUV absorption: Absorption (EM radiation)

Data Source

PatentUS10745580B2Surface-finishing on the basis of cross-linkable, saturated polyester resins and fluoropolymers
Publication Date: 2020.08.18 EVONIK OPERATIONS GMBH

AI summary

A formulation for the coating of substrates, the formulation including 5 to 70 wt % of hydroxy-functional fluoropolymers, 5 to 70 wt % of polyesters based on dicarboxylic or polycarboxylic acids or derivatives thereof and on aliphatic or cycloaliphatic diols or polyols, the polyester including at least one aliphatic or cycloaliphatic dicarboxylic acid or polycarboxylic acid or derivatives thereof, 2 to 25 wt % of crosslinkers, 0.01 to 2 wt % of crosslinking catalysts, up to 20 wt % of UV absorbers and up to 10 wt % of UV stabilizers.