Multi-Layer Plastic Liner for Aerosol Containers
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Solution Overview
Problem
Existing aerosol containers for aggressive products, such as hair mousse, face challenges due to the use of toxic polyamide-imide lacquer coatings, which may be banned under REACH regulations, and propellant diffusion through plastic liners, reducing the container's effectiveness over time.
Innovation Solution
A multi-layer plastic liner with a nylon outer layer, a low-density polyethylene inner layer, and an adhesive tie-layer is used within an aerosol container to prevent propellant diffusion and protect the product, allowing for a safer and more durable packaging solution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a polyamide-imide lacquer coating is used inside the aerosol container, then corrosion resistance is improved, but toxicity and environmental harm increase
Solution Approach 1:
A plastic liner is introduced as an intermediary component between the aggressive product/propellant and the metal aerosol container. The liner is made from polyolefin material that is chemically resistant to the product while being impermeable to propellant. This mediator protects the container from corrosion without requiring toxic lacquer coatings, thereby eliminating the harmful chemical substances while maintaining structural integrity.
Solution Approach 2:
The aerosol container employs a composite structure combining metal (for strength and form) with a plastic liner (for chemical resistance). This composite approach allows the system to benefit from both materials: the metal provides structural strength while the plastic liner provides chemical inertness and propellant barrier properties, eliminating the need for toxic coatings.
2Reliability
If a plastic liner is used to protect the container, then corrosion resistance is improved, but propellant diffusion through the liner increases over time
Solution Approach 1:
The liner is constructed as a multi-layer composite structure with an outer polyolefin layer providing chemical resistance and an inner layer providing propellant barrier properties. This composite construction addresses both requirements: protection from corrosion and prevention of propellant diffusion.
Solution Approach 2:
Different regions of the liner have different material properties optimized for their specific functions. The outer layer contacts the aggressive product and provides chemical resistance, while the inner layer contacts the propellant and provides diffusion barrier properties. This local differentiation of material qualities resolves the contradiction between protection and containment.
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 multi-layer liner effectively contains aggressive products and propellants, reducing the risk of toxic lacquer use and maintaining the container's performance by preventing propellant diffusion, thus providing a socially responsible and effective packaging solution.
Implementation Method 1
the plastic liner is preferably made from a polyolefin material, more preferably high density polyethylene or polypropylene. However, this patent also notes that hydrocarbon propellants will diffuse through polyolefin materials with time.
Data Source
AI summary
The invention provides an aerosol container having an outer container body (10) with a plastic liner or bag (40) arranged therein, into which both product and propellant are filled, characterized in that the plastic liner or bag (40) has a multi-layer construction. The liner or bag (40) comprises a layer that is resistant to the product and a layer that prevents diffusion of the propellant out of the liner or bag (40). Further layers may also be incorporated to provide additional properties as required, for example an oxygen barrier, scavenging etc. Furthermore, one or more tie-layers, such as adhesive for example, may be provided to hold the separate layers together.