Layer Migration Control Agent for Wet-on-Wet Coating

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Solution Overview

Problem

Conventional wet-on-wet coating methods for multilayer coating films face issues with layer migration, resulting in degraded appearance and low water resistance, along with prolonged drying times.

Innovation Solution

A graft copolymer is used as a layer migration control agent, composed of an ether group-containing polymerizable unsaturated monomer and a hydrophobic polymerizable unsaturated monomer, to suppress layer mixing and enhance the appearance and water resistance of the cured coating film while shortening drying time.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If conventional wet-on-wet coating method is used, then coating process efficiency is improved, but layer migration occurs causing degraded appearance and low water resistance

Engineering Contradiction:

Improvecoating process efficiencyVSAvoidlayer orientation

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The patent introduces a layer migration control agent as an intermediary substance between the prime coating layer and top coating layer. This agent prevents direct mixing of the two layers while allowing the wet-on-wet coating process to proceed, thereby maintaining coating efficiency while preventing layer migration and preserving metallic pigment orientation

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent modifies the chemical composition parameters of the coating system by adding a specific copolymer containing hydrophobic groups and ether groups. This parameter change alters the interfacial properties between layers, creating a barrier that prevents mixing while maintaining the benefits of the wet-on-wet process

Inventive Principle:

Principle #35Parameter changes

2Duration of action of moving object

If conventional wet-on-wet coating method is used, then drying time is prolonged, but energy consumption increases

Engineering Contradiction:

Improvedrying timeVSAvoidenergy consumption

Core Design Contradiction:

Duration of action of moving objectVSUse of energy by stationary object

Solution Approach 1:

The copolymer additive changes the evaporation kinetics parameters of the coating system. The hydrophobic groups and ether groups in the copolymer modify how solvents evaporate from the coating, enabling faster drying times without requiring additional energy input or extended drying periods

Inventive Principle:

Principle #35Parameter changes

3Manufacturing precision

If conventional layer migration prevention methods are used, then layer mixing is suppressed, but water resistance deteriorates

Engineering Contradiction:

Improvelayer orientationVSAvoidwater resistance

Core Design Contradiction:

Manufacturing precisionVSReliability

Solution Approach 1:

The patent uses a composite copolymer structure combining hydrophobic groups (for water resistance) and ether groups (for layer migration control). This composite material approach allows simultaneous achievement of both layer orientation preservation and water resistance enhancement that cannot be achieved with single-function additives

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 copolymer effectively prevents layer migration, maintaining the finish appearance and water resistance of the coating film while reducing drying time, thereby improving the overall coating process efficiency.

Implementation Method 1

a graft copolymer obtained using an ether group-containing polymerizable unsaturated monomer (A) and a polymerizable unsaturated monomer (B) having a hydrophobic group as the main starting materials

Methodology Applied

Scientific EffectSteric hindrance:

Implementation Method 2

a graft copolymer obtained using an ether group-containing polymerizable unsaturated monomer (A) and a polymerizable unsaturated monomer (B) having a hydrophobic group as the main starting materials

Methodology Applied

Scientific EffectHydrophobic interaction: Hydrophobe

Implementation Method 3

a graft copolymer obtained using an ether group-containing polymerizable unsaturated monomer (A) and a polymerizable unsaturated monomer (B) having a hydrophobic group as the main starting materials, the molecular skeleton thereof being configured of a hydrophobic trunk polymer derived from the monomer (B) and a hydrophilic branch polymer composed of an ether group derived from the monomer (A)

Methodology Applied

Scientific EffectAmphiphilic structure: Amphiphiles

Data Source

PatentEP3281988B1Layer migration control agent

Publication Date: 2020.01.15 KUSUMOTO CHEM

AI summary

Provided is a novel layer migration control agent that is added to a paint composition when forming a multilayer coating film on a coating object by curing a prime coating film and a top coating film at the same time, the agent making it possible to control layer migration of the two coating films and obtain the multilayer coating film with satisfactory finish appearance. The layer migration control agent is a copolymer obtained by copolymerization of a monomer mixture including 5% by weight to 90% by weight of a polymerizable unsaturated monomer including an ether group and 10% by weight to 95% by weight of a polymerizable unsaturated monomer having a hydrophobic group having 1 to 22 carbon atoms, the copolymer having a weight average molecular weight of 1000 to 100,000.