Single-Layer Coating via Melt-Blended Polymer Network

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Solution Overview

Problem

Current coating compositions for metal food and beverage containers face challenges with flexibility, adhesion, sterilization resistance, and blush resistance, often requiring multiple layers and containing undesirable materials like BPA and aromatic glycidyl ethers, which complicate the coating process and pose health risks.

Innovation Solution

An organic solvent-based dispersion is created through a melt-blended network of epoxy-functional and/or amino-functional polymers with polymer-O—Si—O-polymer linkages and polyolefin copolymers, combined with a film-forming polymer, crosslinker, and acid catalyst, eliminating the need for multiple coating layers and reducing the presence of harmful substances.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional coating compositions are used to ensure adequate protection and adhesion, then coating reliability is improved, but the coating process complexity increases requiring multiple layers

Engineering Contradiction:
Improvecoating protection and adhesionVSAvoidcoating process complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines multiple coating functions into a single composition by integrating polyester polymer, silane-functional compound, and polyolefin copolymer in one layer, eliminating the need for separate primer and topcoat applications while maintaining adequate adhesion and protection properties

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The coating composition is designed to perform multiple functions simultaneously: providing adhesion to metal substrates, offering corrosion protection, enabling easy-open lid separation, and ensuring food safety, all within a single coating layer that replaces traditional multi-layer systems

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Reliability

If conventional coating compositions containing BPA and aromatic glycidyl ethers are used to achieve desired coating properties, then coating performance is improved, but harmful factors increase posing health risks

Engineering Contradiction:
Improvecoating performanceVSAvoidharmful substances
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent explicitly excludes harmful substances BPA and aromatic glycidyl ethers from the coating composition formulation, removing these harmful components while maintaining coating performance through alternative safe polymers and crosslinking mechanisms

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent changes the chemical composition parameters by using polyester polymers with specific hydroxyl values and silane-functional compounds as safe alternatives to traditional epoxy-based systems containing harmful substances, achieving the same protective function without health risks

Inventive Principle:
Principle #35Parameter changes

3Quantity of substance

If very thin coating films of no more than 10 μm are applied to reduce material usage, then substance consumption is reduced, but manufacturing precision requirements increase to ensure uniformity

Engineering Contradiction:
Improvecoating material consumptionVSAvoidfilm uniformity
Core Design Contradiction:
Quantity of substanceVSManufacturing precision

Solution Approach 1:

The patent adjusts the viscosity and flow characteristics of the coating composition by selecting specific polyester polymers and solvents, enabling the formulation to self-level and flow uniformly at very thin application thicknesses of 10 μm or less, reducing the need for precise manufacturing control

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 solution provides a single-layer coating with enhanced flexibility, adhesion, and resistance to sterilization, while being free from harmful substances, simplifying the coating process and ensuring food safety.

Implementation Method 1

forming the melt-blended network from a prepolymer, a silane-functional compound and the polyolefin (co)polymer in the absence of a solvent

Methodology Applied
Scientific EffectSilane crosslinking: Chemical Bonding

Implementation Method 2

an acid catalyst

Methodology Applied
Scientific EffectCatalysis: Catalysis

Data Source

PatentUS10233352B2Process or preparing organic solvent-based dispersions, coating compositions and coated metal substrate useful for packaging applications
Publication Date: 2019.03.19 AKZO NOBEL COATINGS INT BV

AI summary

The invention relates to a process for preparing an organic solvent-based dispersion comprising a melt-blended network of an epoxy-functional and/or amino-functional polymer having a polymer-O—Si—O-polymer linkage and a polyolefin (co)polymer having carboxylic acid and/or carboxylic acid anhydride groups, the process comprising the steps of a) forming the melt-blended network from a prepolymer, a silane-functional compound and the polyolefin (co)polymer in the absence of a solvent, b) mixing the melt-blended network with an organic solvent to make the organic solvent-based dispersion, and c) cooling the organic solvent-based dispersion. The invention further relates to a coating composition and to a coated metal substrate.