Dual-Cure Coating Composition for Automotive Refinish

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Solution Overview

Problem

Existing automotive coatings face challenges with uneven curing, particularly in complex geometries and shaded areas, as well as compatibility issues with overlapping regions of original manufacturer coatings, due to limitations in mono-cure and dual-cure coatings.

Innovation Solution

A coating composition comprising components with chemically crosslinkable and radiation crosslinkable functional groups, allowing for curing by UV radiation, chemical crosslinking, or both, with a flexible formulation that can be used as a one-package or two-package system, enabling indefinite pot life until exposure to actinic radiation and rapid formation of a dry coating.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If UV radiation curing is used for mono-cure coatings, then curing speed is improved and indefinite pot life is maintained, but uneven curing occurs in complex geometries and shaded areas

Engineering Contradiction:
Improvecuring speedVSAvoidcuring uniformity
Core Design Contradiction:
SpeedVSManufacturing precision

Solution Approach 1:

The patent segments the curing mechanism into two independent parts: UV radiation curing (for rapid surface curing) and chemical crosslinking (for complete throughout curing). This segmentation allows each mechanism to perform its optimal function - UV provides speed while chemical crosslinking ensures uniformity in complex geometries.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent creates a composite curing system combining UV-curable components (acrylic polymers with double bonds) and chemically crosslinkable components (isocyanates, polyols). This composite approach integrates two different curing mechanisms into a single coating formulation, enabling both rapid initial curing and complete uniform curing.

Inventive Principle:
Principle #40Composite materials

2Reliability

If dual-cure coatings with separate components are used, then curing completeness is improved, but device complexity and storage requirements worsen

Engineering Contradiction:
Improvecuring completenessVSAvoidpackaging complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the UV-curable components and chemically crosslinkable components into a single one-package formulation. The coating contains both acrylic polymers with double bonds and isocyanate/polyol components in the same container, eliminating the need for separate packaging and complex mixing procedures while maintaining complete curing capability.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent creates a universal coating composition that can cure through multiple mechanisms (UV radiation and chemical crosslinking) within a single formulation. This multi-functional coating can adapt to different application requirements - rapid curing when UV is available, or complete curing in complex geometries through chemical crosslinking.

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

3Reliability

If dual-cure coatings with crosslinking agents are used, then curing completeness is improved, but pot life is reduced

Engineering Contradiction:
Improvecuring completenessVSAvoidpot life
Core Design Contradiction:
ReliabilityVSDuration of action of moving object

Solution Approach 1:

The patent creates a dynamic system where the chemical crosslinking reaction remains dormant until activated by UV radiation. The coating maintains its original composition with both UV-curable and chemically crosslinkable components in equilibrium, and only initiates chemical crosslinking after UV exposure, thereby maintaining indefinite pot life while ensuring complete curing.

Inventive Principle:
Principle #15Dynamics

4Duration of action of moving object

If mono-cure UV coatings are used, then pot life is maintained indefinitely, but compatibility with original manufacturer coatings deteriorates

Engineering Contradiction:
Improvepot lifeVSAvoidcompatibility with OEM coatings
Core Design Contradiction:
Duration of action of moving objectVSAdaptability or versatility

Solution Approach 1:

The patent creates a composite coating formulation that combines UV-curable acrylic polymers with chemically crosslinkable components. This composite structure provides both the indefinite pot life of UV coatings and the compatibility characteristics of chemically crosslinking coatings, allowing adhesion to various OEM coating types through the chemical crosslinking mechanism.

Inventive Principle:
Principle #40Composite materials

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 ensures even curing on complex substrates, maintains compatibility with original manufacturer coatings, and provides flexibility in application, allowing for curing without reliance on uniform UV radiation, thus addressing the limitations of traditional mono-cure and dual-cure coatings.

Implementation Method 1

A UV curable coating composition can be cured by UV radiation in which the double bonds of the acrylic groups undergo polymerization to form a crosslinked network

Methodology Applied
Scientific EffectPhotopolymerization: Photopolymerisation

Implementation Method 2

A coating curable by chemical crosslinking typically contains crosslinkable groups, such as hydroxyl groups, and corresponding crosslinking groups, such as isocyanate groups

Methodology Applied
Scientific EffectChemical crosslinking: Chemical Bonding

Data Source

PatentUS9309433B2Radiation and chemical curable coating composition
Publication Date: 2016.04.12 AXALTA COATING SYSTEMS IP CO LLC

AI summary

The disclosure relates to a coating composition comprising a component A comprising one or more acrylic polymers having one or more chemically crosslinkable functional groups X selected from hydroxyl, thiol, isocyanate, epoxy, acid, thioisocyanate, acetoacetoxy, carboxyl, amine, anhydride, ketimine, aldimine, or urethane group; and a component B comprising one or more monomers or oligomers having one or more functional groups Y that react with the functional groups X to form a crosslink and one or more radiation crosslinkable functional groups D which are radiation crosslinkable ethylenically unsaturated double bonds; wherein said functional groups X and Y are pair-wise selected from hydroxyl and isocyanate groups, thiol and isocyanate groups, epoxy and acid groups, epoxy and isocyanate groups, isocyanate and amine groups, or isocyanate and urethane groups. This disclosure is also directed to a method of using said coating composition to coat a substrate including a vehicle, a vehicle body or parts thereof.