Transesterification Clear Coating for Acid Resistance and Low Formaldehyde

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Solution Overview

Problem

Conventional clear coating compositions for multilayer coatings face issues with acid resistance, formaldehyde generation, and storage stability, and are costly, while existing alternatives like non-melamine curing systems have toxicity and stability problems.

Innovation Solution

A method for forming a multilayer coating film using a clear coating composition that undergoes a transesterification reaction between hydroxyl groups and alkyl ester groups, allowing for a wet-on-wet application process with simultaneous curing, using a water-borne base coating composition containing melamine resin and a solvent-based or water-borne clear coating composition with a tertiary alkyl ester group for improved curing performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If melamine resin is used in clear coating composition, then curing performance is improved, but formaldehyde generation occurs and acid resistance deteriorates

Engineering Contradiction:

Improvecuring performanceVSAvoidformaldehyde generation

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent extracts and removes the melamine resin component from the clear coating composition to eliminate formaldehyde generation and improve acid resistance, while replacing it with alternative curing agents that maintain curing performance without harmful effects

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent converts the harmful formaldehyde generation side effect of melamine resin into a beneficial alternative curing system using isocyanate or epoxy groups that achieve crosslinking without formaldehyde emission, thereby transforming a harmful chemical pathway into a safe one

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

2Object-generated harmful factors

If non-melamine curing systems (isocyanate or epoxy) are used, then formaldehyde generation is reduced, but storage stability deteriorates and equipment burden increases

Engineering Contradiction:

Improveformaldehyde generationVSAvoidstorage stability

Core Design Contradiction:

Object-generated harmful factorsVSStability of the object's composition

Solution Approach 1:

The patent changes the chemical parameters of the curing system by using isocyanate groups or epoxy groups instead of melamine resin, and adjusts the formulation to achieve both low formaldehyde emission and improved storage stability through careful selection of resin combinations and catalysts

Inventive Principle:

Principle #35Parameter changes

3Reliability

If conventional clear coating compositions are used, then curing performance is achieved, but cost increases

Engineering Contradiction:

Improvecuring performanceVSAvoidcost

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

The patent employs cost-effective resin combinations and curing agents that provide adequate curing performance at lower material costs, replacing expensive conventional clear coating formulations with more economical alternatives that meet performance requirements

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

4Reliability

If melamine resin is used in clear coating composition, then curing performance is improved, but acid resistance deteriorates

Engineering Contradiction:

Improvecuring performanceVSAvoidacid resistance

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent removes melamine resin from the clear coating composition to eliminate the source of acid resistance problems, while maintaining curing performance through alternative crosslinking mechanisms using isocyanate or epoxy groups that do not suffer from acid degradation

Inventive Principle:

Principle #2Taking out (Extraction)

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 method results in a multilayer coating film with excellent acid resistance, reduced formaldehyde generation, improved storage stability, and lower costs, while maintaining high curing performance and safety.

Implementation Method 1

the clear coating composition causes a curing reaction through a transesterification reaction between a hydroxyl group and an alkyl ester group

Methodology Applied

Scientific EffectTransesterification reaction: Chemical Bonding

Data Source

PatentUS11618816B2Method for forming a multilayer coating film and multilayer coating film

Publication Date: 2023.04.04 KYOEISHA CHEM CO LTD

AI summary

An object of the present invention is to provide a method for forming a multilayer coating film with excellent performance such as acid resistance, by using a coating composition which is completely different from conventional clear coating compositions and cheaper than conventional non-melamine curing type, acid/epoxy type, and isocyanate type clear coating compositions. A method for forming a multilayer coating film comprising a step (1) of applying a base coating composition and a step (2) of applying a clear coating composition on a coating film formed in the step (1), wherein the clear coating composition causes a curing reaction through a transesterification reaction between a hydroxyl group and an alkyl ester group.