BPA-Free Packaging Coating Composition for Corrosion Resistance

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Solution Overview

Problem

Current packaging coatings for metal food and beverage containers face challenges such as corrosion, contamination, and the need for improved safety and durability, particularly with the limitations of polyvinyl-chloride-based and epoxy-based coatings that contain bisphenol A (BPA) compounds.

Innovation Solution

A coating composition using a polyether polymer with a glass transition temperature of at least 70°C, free from structural units derived from BPA or diglycidyl ether of BPA, which includes polycyclic groups and secondary hydroxyl groups, providing excellent adhesion, corrosion resistance, and stability for use on food-contact surfaces.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If epoxy-based coatings incorporating BPA are used, then adhesion and corrosion resistance are improved, but safety concerns arise due to BPA contamination

Engineering Contradiction:

Improvecorrosion resistanceVSAvoidBPA contamination

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent changes the chemical composition parameters by using alternative polymers (polyester, acrylic, vinyl) with modified molecular structures that eliminate BPA while maintaining coating performance through adjusted formulation ratios and curing mechanisms

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention creates composite coating formulations combining multiple polymer types (polyester resins with acrylic components, or vinyl with polyester) to achieve the adhesion and corrosion resistance previously provided by BPA-based epoxies, without using harmful substances

Inventive Principle:

Principle #40Composite materials

2Reliability

If polyvinyl-chloride-based coatings are used, then coating performance is achieved, but recycling becomes problematic

Engineering Contradiction:

Improvecoating performanceVSAvoidrecyclability

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent changes the chemical composition from polyvinyl-chloride to polyester, acrylic, or vinyl polymer bases that are compatible with metal recycling processes, allowing the coating to be removed or degraded more easily during container recycling while maintaining protective performance

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention adopts coating formulations that are designed to be less permanent and more easily removable during recycling, sacrificing some long-term durability in favor of improved recyclability and environmental sustainability

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

3Strength

If high crosslink density is achieved through BADGE, then film integrity is improved, but BPA-free requirement creates formulation challenges

Engineering Contradiction:

Improvefilm integrityVSAvoidBPA derivatives

Core Design Contradiction:

StrengthVSObject-affected harmful factors

Solution Approach 1:

The patent changes the crosslinking chemistry by using alternative polymers with inherent crosslinking capabilities or adding separate crosslinking agents that do not contain BPA, adjusting the crosslink density through formulation optimization to maintain film integrity without BADGE

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention introduces intermediary substances such as silane crosslinkers, isocyanate crosslinkers, or anhydride crosslinkers that mediate the crosslinking process between polymer chains, providing the necessary film integrity and crosslink density without using BPA-based BADGE

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS11130881B2Coating compositions for packaging articles and methods of coating

Publication Date: 2021.09.28 SWIMC LLC

AI summary

This invention provides a polymer that is useful in a variety of applications, including as a binder polymer of a coating composition, and especially a packaging coating composition. Packaging articles (e.g., containers) comprising the polymer and methods of making such packaging articles are also provided.