Wet-on-Wet Primer Composition for Fast Cure and Corrosion Protection

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Solution Overview

Problem

Existing primer compositions for wet-on-wet applications either cure too slowly, leading to poor corrosion protection and adhesion, or cure too quickly, resulting in solvent entrapment and coating flaws, while achieving both rapid curing and effective corrosion protection remains a challenge.

Innovation Solution

A primer composition combining epoxy resin, multifunctional acrylic resin, and a phenalkamine crosslinking agent, along with a volatile solvent system, is used to achieve rapid curing and good corrosion protection, allowing simultaneous application and curing with top coats.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If epoxy primer compositions are used to provide good corrosion protection, then corrosion protection is improved, but curing speed is slow leading to poor appearance and slippage in wet-on-wet applications

Engineering Contradiction:
Improvecorrosion protectionVSAvoidcuring speed
Core Design Contradiction:
ReliabilityVSSpeed

Solution Approach 1:

The patent modifies the chemical composition parameters of the epoxy primer by incorporating specific solvents (acetone, ethyl acetate, butyl acetate) and curing agents in controlled amounts to optimize both corrosion protection and curing speed for wet-on-wet applications

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite primer composition combining epoxy resin with specific additives and solvents to achieve dual functionality: maintaining excellent corrosion protection while enabling rapid curing compatible with wet-on-wet top coat application

Inventive Principle:
Principle #40Composite materials

2Productivity

If rapid curing is achieved to enable wet-on-wet application, then productivity is improved, but solvent entrapment occurs leading to coating flaws and reduced adhesion

Engineering Contradiction:
Improveapplication speedVSAvoidcoating quality
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent carefully controls solvent composition and concentration (acetone, ethyl acetate, butyl acetate) to enable rapid evaporation during quick drying, preventing solvent entrapment while maintaining rapid curing suitable for wet-on-wet application

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates different functional zones within the primer composition: fast-evaporating solvent components for rapid moisture release, epoxy resin for corrosion protection, and curing agents for controlled crosslinking, each performing its function in a specific temporal sequence

Inventive Principle:
Principle #3Local quality

3Manufacturing precision

If slow curing is used to avoid solvent entrapment, then coating quality is improved, but corrosion protection and adhesion are reduced

Engineering Contradiction:
Improvecoating qualityVSAvoidcorrosion protection
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The patent optimizes the balance between solvent content for quality and epoxy/curing agent ratio for corrosion protection, using specific concentrations of acetone, ethyl acetate, and butyl acetate to enable fast drying without compromising the epoxy-based corrosion protection mechanism

Inventive Principle:
Principle #35Parameter changes

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 composition provides rapid curing, excellent corrosion protection, and strong adhesion, with minimal solvent entrapment, resulting in high-quality coatings suitable for automotive applications.

Implementation Method 1

A crosslinking component is also present in the primer composition, where the crosslinking component is an amine

Methodology Applied
Scientific EffectChemical Bonding: Chemical Bonding

Implementation Method 2

an epoxy resin with a plurality of epoxy moieties

Methodology Applied
Scientific EffectChemical Bonding: Chemical Bonding

Implementation Method 3

having solvents that quickly evaporate after application such that the cured primer coat is not softened due to solvent entrapment

Methodology Applied
Scientific EffectEvaporation: Evaporation

Data Source

PatentEP3862396B1Primer compositions and methods of coating a substrate
Publication Date: 2025.12.03 AXALTA COATING SYSTEMS IP CO LLC
  • EP3862396B1 patent drawingFigure 1~3
  • EP3862396B1 patent drawingFigure 4~5
  • EP3862396B1 patent drawing

AI summary

Primer compositions and methods of using the same are provided. In an exemplary embodiment, a primer composition includes an epoxy resin with a plurality of epoxy moieties. The primer composition also includes a (meth)acrylic resin with a plurality of (meth)acrylic moieties covalently bonded to an organic moiety. A crosslinking component is also present in the primer composition, where the crosslinking component is an amine.