Aqueous Polyester Dispersion for Food Packaging Coatings

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Solution Overview

Problem

Current packaging coatings face challenges such as problematic recycling of polyvinyl chloride-based materials and the presence of bisphenol A and related compounds, which are perceived as potentially harmful to human health, and struggle to balance corrosion resistance and fabrication properties in polyester-based coatings.

Innovation Solution

Development of aqueous polyester dispersions comprising a hydrophobic aromatic polyester and a water-dispersible aromatic polyester dispersant, forming a stable dispersion suitable for coating metal substrates in food or beverage cans, without significant bisphenol A, F, or S contamination, and with improved corrosion resistance and flexibility.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

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

Engineering Contradiction:

Improvecoating performanceVSAvoidrecycling

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The invention extracts and eliminates polyvinyl chloride and related halogen-containing vinyl polymers from packaging coating applications. By removing these problematic materials entirely and replacing them with alternative polymer systems, the patent resolves the contradiction between achieving good coating performance and enabling recyclability.

Inventive Principle:

Principle #2Taking out (Extraction)

2Reliability

If coatings containing bisphenol A, BPF, or BPS are used, then coating durability is improved, but health safety concerns arise

Engineering Contradiction:

Improvecoating durabilityVSAvoidhealth safety

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The invention extracts and eliminates bisphenol A, bisphenol F, bisphenol S, and aromatic glycidyl ether compounds from coating formulations. By removing these potentially harmful compounds while maintaining coating durability through alternative binder systems, the patent resolves the contradiction between coating durability and health safety.

Inventive Principle:

Principle #2Taking out (Extraction)

3Reliability

If polyester-based coatings are formulated for corrosion resistance, then protection is improved, but fabrication properties deteriorate

Engineering Contradiction:

Improvecorrosion resistanceVSAvoidfabrication properties

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The invention changes key parameters of polyester-based coatings, specifically adjusting molecular weight, functional group content, and compositional ratios to achieve an optimal balance between corrosion resistance and fabrication properties. By modifying these parameters, the patent resolves the contradiction between protection performance and manufacturability.

Inventive Principle:

Principle #35Parameter changes

4Object-affected harmful factors

If water-based coatings are used, then environmental friendliness is improved, but coating performance stability worsens

Engineering Contradiction:

Improveenvironmental impactVSAvoidcoating performance stability

Core Design Contradiction:

Object-affected harmful factorsVSStability of the object's composition

Solution Approach 1:

The invention creates composite aqueous polyester dispersion systems that combine multiple components with complementary functions. By formulating composite materials that include polyester resins, dispersants, and other additives in specific ratios, the patent achieves both environmental friendliness through water-based formulation and stable coating performance.

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 solution provides a stable, bisphenol-free coating with enhanced corrosion resistance and flexibility, suitable for food and beverage packaging, addressing the recycling and health concerns while maintaining performance characteristics.

Implementation Method 1

a hydrophobic aromatic polyester and a water-dispersible aromatic polyester dispersant form a stable aqueous dispersion

Methodology Applied

Scientific EffectDispersion: Dispersion (of waves)

Data Source

PatentUS11021613B2Aqueous polyester dispersions, articles having a coating formed from such aqueous dispersions, and methods of coating

Publication Date: 2021.06.01 SWIMC LLC

AI summary

An aqueous dispersion comprising: water; a hydrophobic aromatic polyester having a number average molecular weight of greater than 7,000 Daltons; and a water-dispersible aromatic polyester dispersant; wherein the hydrophobic aromatic polyester and the water-dispersible aromatic polyester dispersant form a stable aqueous dispersion; and wherein the hydrophobic aromatic polyester is present in the aqueous dispersion in an amount of less than 50 wt-%, based on the total weight of the hydrophobic aromatic polyester and the water-dispersible aromatic polyester dispersant.