Ethylene Copolymer Extruded Web Barrier Laminates
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Solution Overview
Problem
Current laminates used in flexible packaging, such as those with polypropylene, polyamide, and polyethylene terephthalate, are difficult to recycle due to incompatible materials, hindering sustainability efforts despite offering good performance properties like heat-resistance and printability.
Innovation Solution
Development of laminates composed of a first film with at least 95 wt.% polyethylene, a lamination layer with ethylene copolymers, a barrier layer of ethylene vinyl alcohol copolymer, and an extruded web layer using ethylene-based copolymers, allowing for recyclability and maintaining or improving properties like bond strength and heat seal performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If laminates incorporate multiple materials like polypropylene, polyamide, and polyethylene terephthalate to achieve good performance properties, then heat-resistance, printability, and barrier performance are improved, but recyclability deteriorates due to incompatible materials
Solution Approach 1:
The laminate structure is redesigned to use polyethylene as the common base material for both the outer printing substrate and the sealant layer, creating material homogeneity. The barrier layer and adhesive layers are the only non-polyethylene components, significantly reducing material diversity compared to traditional multi-material laminates. This homogeneity enables the entire laminate to be recycled in polyethylene recycling streams while maintaining required performance properties.
Solution Approach 2:
The patent employs composite material strategies by using polyethylene blends and copolymers with specific properties (e.g., linear low-density polyethylene, low-density polyethylene) to achieve the desired balance between performance and recyclability. The adhesive layer uses compatible polymers like polyethylene elastomer or polyethylene plastomer that maintain adhesion functionality while being recyclable with the polyethylene substrate.
2Reliability
If traditional multi-layer laminates are used to ensure barrier performance and heat resistance, then oxygen transmission rate and heat seal strength are improved, but manufacturing complexity increases
Solution Approach 1:
The patent extracts and removes unnecessary intermediate layers from traditional laminate structures. By using polyethylene for both the outer substrate and sealant layer, and selecting adhesives that are compatible with polyethylene, the design eliminates the need for multiple tie layers and complex adhesive systems, simplifying the overall structure while maintaining barrier performance through the retained essential layers.
Solution Approach 2:
Polyethylene serves multiple functions in the laminate structure: it acts as the outer printing substrate, provides the sealant layer, and serves as the base material for recycling. This multi-functionality reduces the number of different materials needed and simplifies the laminate architecture while maintaining heat resistance and barrier properties through proper layer configuration.
3Ease of manufacture
If polyethylene is used as the base material for recyclability, then recyclability is improved, but heat-resistance may deteriorate compared to polypropylene-based laminates
Solution Approach 1:
The patent adjusts the molecular weight distribution, density, and crystallinity parameters of the polyethylene materials used in different layers to optimize heat resistance. By selecting specific grades of linear low-density polyethylene and low-density polyethylene with appropriate melt indices and molecular characteristics, the laminate achieves improved thermal stability and heat seal performance while maintaining recyclability in polyethylene streams.
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 laminates are fully recyclable, maintain or enhance properties like bond strength, oxygen transmission rate, and heat seal performance, enabling faster packaging speeds and zero shrinkage within a specific temperature range, thus addressing recyclability and performance gaps in existing laminates.
Implementation Method 1
an extruded web layer adhering the lamination layer of the second film to the first film
Implementation Method 2
a barrier layer comprising an ethylene vinyl alcohol copolymer
Implementation Method 3
the sealant layer comprises at least 70 wt. % of a polymer having a highest peak melting temperature (Tm) of 108° C. or less
Data Source
AI summary
Provided are laminates including polyethylene and an extruded web layer. The laminates can be adhesiveless and fully compatible with polyethylene recycling streams. They can exhibit improved, maintained, or desirable properties in comparison to existing laminate structures that are not fully compatible with polyethylene recycling streams. The laminate comprises a first film, an extruded web layer, and a second film, where the extruded web layer is between the first film and a lamination layer of the second film and the laminate is formed via extrusion lamination of the extruded web layer.