Near-IR Absorber Multilayer Coating for Low-Temperature Curing

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Solution Overview

Problem

Existing coating formulations require high temperatures for curing, leading to high energy consumption and environmental impact, and conventional near-infrared absorbing additives affect the color of the coatings.

Innovation Solution

A multilayer coating system comprising a first coating with a near-infrared absorber and a second coating, where the near-infrared absorber is used to reduce cure temperatures or bake cycles while maintaining the desired appearance and color, by absorbing increased amounts of infrared radiation and transferring heat to the second coating for faster curing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If conventional near-IR absorbing additives are used to reduce cure temperatures, then energy consumption is reduced, but the color of the coating is affected

Engineering Contradiction:
Improveenergy consumptionVSAvoidcolor accuracy
Core Design Contradiction:
Use of energy by moving objectVSManufacturing precision

Solution Approach 1:

The coating system is divided into multiple layers with different functions: the first layer contains the near-IR absorber for energy absorption and heat generation, while the second layer is formulated specifically to maintain color accuracy and appearance. This segmentation allows each layer to optimize its specific function without compromising the other.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the coating system are assigned different properties: the first coating layer has high near-IR absorption capability, while the second coating layer has optimized optical properties for color accuracy. This local differentiation resolves the contradiction by placing the IR absorber only where needed for energy efficiency without affecting the overall color appearance.

Inventive Principle:
Principle #3Local quality

2Reliability

If high temperatures are used to cure thermosetting formulations, then complete curing is achieved, but energy consumption and environmental impact increase

Engineering Contradiction:
Improvecuring completenessVSAvoidenergy consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent replaces conventional thermal convection heating with near-infrared radiative heating. The near-IR absorber converts radiant energy directly into heat within the coating, eliminating the need for high-temperature convection ovens and significantly reducing energy consumption while maintaining effective curing.

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

Solution Approach 2:

The curing process parameters are changed from high-temperature convection (traditional) to lower-temperature near-IR radiation. The near-IR absorber enables effective curing at lower temperatures by directly converting radiant energy to heat, thereby reducing energy consumption and environmental impact.

Inventive Principle:
Principle #35Parameter changes

3Loss of time

If near-IR lamps are used for curing, then residence time is reduced, but the complexity of the curing system increases

Engineering Contradiction:
Improveresidence timeVSAvoidcuring system complexity
Core Design Contradiction:
Loss of timeVSDevice complexity

Solution Approach 1:

The near-IR absorber acts as an intermediary substance that facilitates the curing process. It absorbs the near-IR radiation and converts it to heat, which then cures the coating. This intermediary enables rapid curing with near-IR lamps while the multilayer coating structure manages the optical and thermal properties to maintain simplicity.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 multilayer coating system achieves energy efficiency and faster curing times while minimizing color shifts, reducing energy consumption and environmental impact without compromising the appearance of the coated object.

Implementation Method 1

Near-infrared (IR) lamps direct energy to coatings by radiative transfer

Methodology Applied
Scientific EffectNear-infrared radiation absorption: Absorption (EM radiation)

Implementation Method 2

radiative heating is a more rapid process than convection heating

Methodology Applied
Scientific EffectRadiative heating: Thermal Radiation

Data Source

PatentUS9017815B2Near-infrared radiation curable multilayer coating systems and methods for applying same
Publication Date: 2015.04.28 PPG INDUSTRIES OHIO INC

AI summary

Multilayer coating systems, methods of applying and related substrates are disclosed. The coating system may comprise a first coating comprising a near-IR absorber, and a second coating deposited on a least a portion of the first coating. Methods of applying a multilayer coating composition to a substrate may comprise applying a first coating comprising a near-IR absorber, applying a second coating over at least a portion of the first coating and curing the coating with near infrared radiation.