Coextruded Multi-Layer Foil for Solvent-Resistant Flexible Packaging
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing multi-layer foils for flexible packaging exhibit insufficient chemical resistance, particularly when used for liquid chemical products, leading to leakage and reduced shelf life.
Innovation Solution
A multi-layer foil structure comprising an inner layer of ethylene-vinyl alcohol copolymer (EVOH) and/or polyvinyl alcohol (PVOH) with outer layers of polyolefin, specifically designed to prevent gas and solvent permeation, and produced through coextrusion without adhesives, ensuring flexibility and chemical stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional multi-layer foils are used for flexible packaging, then the packaging structure is simple and easy to manufacture, but the chemical resistance is insufficient leading to leakage
Solution Approach 1:
The patent applies composite materials by combining three different polymer layers: an inner layer (polyolefin or polyamide), a middle layer (EVOH for oxygen barrier), and an outer layer (polyester or polypropylene for mechanical strength). This composite structure provides enhanced chemical resistance while maintaining flexibility, directly resolving the contradiction between reliability and structural complexity.
2Reliability
If polymer layers are used for flexible packaging, then the packaging is flexible and lightweight, but the polymer swells when exposed to organic solvents leading to dissolution and leakage
Solution Approach 1:
The patent applies local quality by assigning specific functions to different layers: the inner layer provides chemical resistance and solvent barrier properties, the middle EVOH layer provides oxygen barrier properties, and the outer layer provides mechanical strength and flexibility. Each layer is optimized for its specific function, allowing the packaging to resist solvent permeation while maintaining overall structural stability.
Solution Approach 2:
The multi-layer composite structure combines materials with complementary properties: polyolefin/polyamide for chemical resistance, EVOH for gas barrier, and polyester/polypropylene for mechanical performance. This composite approach prevents polymer swelling and dissolution in organic solvents while maintaining flexibility.
3Reliability
If adhesive layers are used to bond polymer layers, then the multi-layer structure can be assembled, but the adhesive deteriorates upon contact with chemicals leading to delamination
Solution Approach 1:
The patent extracts and eliminates the adhesive layer from the multi-layer structure. Instead of using separate adhesive layers to bond the polymer layers, the invention employs heat-sealable polyolefin or polyamide layers that can be directly bonded through thermal sealing. This removal of the adhesive layer prevents chemical deterioration and delamination while reducing structural complexity.
4Reliability
If flexible packaging material is used for chemical products, then the packaging is lightweight and reduces disposal cost, but the material allows solvent diffusion through the polymer leading to product loss and safety risks
Solution Approach 1:
The patent uses composite materials with specific barrier properties: the inner layer (polyolefin or polyamide) provides resistance to solvent permeation, the middle EVOH layer provides oxygen barrier properties, and the outer layer provides mechanical strength. This composite structure prevents solvent diffusion through the polymer, eliminating product loss and safety risks associated with flexible packaging.
Solution Approach 2:
The inner layer is specifically designed with high chemical resistance and low permeability to organic solvents, while the outer layer provides mechanical protection. This local optimization of material properties at different locations within the packaging structure prevents solvent diffusion while maintaining the overall flexibility and lightweight characteristics.
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 foil provides enhanced barrier properties and chemical resistance, preventing leakage and extending the shelf life of packaged fluids, especially those containing organic solvents or chemicals.
Implementation Method 1
the inner layer comprises ethylene-vinyl alcohol copolymer and/or polyvinyl alcohol... exhibits gas barrier properties, particularly with regard to the permeation of oxygen into the interior of the package
Implementation Method 2
diffusion of the solvent through the polymer, ultimately allowing the contents of the package to spill out... the multi-layer foil provides enhanced barrier properties and chemical resistance, preventing leakage
Data Source
AI summary
The present invention relates to a multi-layer foil comprising an inner layer, a first outer layer on a first side of the inner layer, and a second outer layer on a second side of the inner layer, wherein the inner layer has a thickness of 15 to 60 µm and comprises ethylene-vinyl alcohol copolymer and/or polyvinyl alcohol, the first outer layer has a thickness of 25 to 80 µm and comprises a first polyolefin, and the second outer layer has a thickness of 25 to 80 µm and comprises a second polyolefin. The invention further relates to a flexible packaging comprising the multi-layer foil, to the use of the multi-layer foil in a packaging material for an adhesive, to the use of the multi-layer foil in a packaging material for a two-component system, and to a cartridge comprising a flexible film which comprises the multi-layer foil.