Aqueous Coating Composition for Metal Containers
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Solution Overview
Problem
Existing coatings for metal food and beverage containers, particularly those exposed to acidic products, face corrosion issues due to the use of harmful materials like bisphenol A and organic solvent-based oleoresinous coatings, which also emit volatile organic compounds (VOCs).
Innovation Solution
An aqueous-based coating composition comprising an organic oil, an at least partially neutralized acid functional polymer with reactive groups, and a phenolic compound or its reaction product, dispersed in an aqueous medium, providing corrosion resistance without the use of bisphenol A or high VOCs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If polyglycidyl esters of bisphenol A are used for coating, then corrosion protection is excellent, but harmful substances are present in the coating
Solution Approach 1:
The patent changes the chemical composition parameters by replacing bisphenol A with alternative resins (polyester, vinyl, acrylic) and adjusting the pigment-to-binder ratio to maintain corrosion protection while eliminating harmful substances. The coating formulation is modified to achieve the same protective function without toxic components.
Solution Approach 2:
The patent creates a composite coating system combining multiple resin types (polyester, vinyl, acrylic) with inorganic pigments and corrosion inhibitors to achieve the corrosion resistance previously provided by bisphenol A-based coatings, while eliminating the harmful organic compounds.
2Reliability
If oleoresinous materials are used for coating, then corrosion resistance is excellent, but volatile organic compounds are emitted
Solution Approach 1:
The patent changes the solvent system from organic-based oleoresinous materials to water-based alternatives, adjusting the resin composition and additives to maintain corrosion resistance while eliminating VOC emissions. The formulation parameters are optimized to achieve proper coating performance without harmful volatile compounds.
Solution Approach 2:
The patent substitutes the organic solvent-based system with an aqueous-based system, replacing the chemical mechanism of organic solvents with water as the carrier, thereby eliminating VOC emissions while maintaining the corrosion protection function through alternative resin chemistry.
3Object-generated harmful factors
If aqueous-based coating composition is used, then VOC emissions are reduced, but adhesion and corrosion resistance may be compromised
Solution Approach 1:
The patent develops a composite aqueous-based coating system combining multiple resin types (polyester, vinyl, acrylic) with specific inorganic pigments and corrosion inhibitors to achieve adhesion and corrosion resistance comparable to traditional organic coatings, while maintaining low VOC emissions through the water-based formulation.
Solution Approach 2:
The patent optimizes the chemical composition parameters of the aqueous-based coating, including resin ratios, pigment concentrations, and additive formulations, to enhance adhesion and corrosion resistance while maintaining the environmental benefits of reduced VOC emissions.
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 coating composition effectively prevents corrosion on container surfaces, ensuring food safety and reducing health risks associated with harmful chemicals, while maintaining adhesion and flexibility.
Implementation Method 1
an at least partially neutralized acid functional polymer containing reactive functional groups
Data Source
AI summary
An aqueous-based coating composition suitable as a container coating comprising: (A) a resinous phase of (i) a condensate of (a) an organic oil, a phenol and an aldehyde or (b) an organic oil and a phenol-formaldehyde, (ii) an at least partially neutralized acid functional polymer containing reactive functional groups, and optionally (iii) a phenol, an aldehyde or the reaction product thereof; the resinous phase dispersed in (B) aqueous medium.