Multilayer Ethylene-Based Films for Tear Resistance and PE Recycling
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Solution Overview
Problem
Multilayer films containing different types of polyolefins are difficult to recycle together due to incompatibility, and there is a need for films that exhibit desirable performance properties like tear resistance while being recyclable.
Innovation Solution
The development of multilayer films with a core comprising greater than 90 wt.% ethylene-based polymers, specifically an ethylene-propylene copolymer, which allows for improved tear resistance and compatibility with polyethylene recycling streams.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multilayer films incorporate different types of polyolefins to achieve desirable performance properties, then performance properties are improved, but the films become difficult to recycle due to material incompatibility
Solution Approach 1:
The patent applies homogeneity by ensuring the core layer is composed of greater than 90 wt% ethylene-based polymers, creating a homogeneous polyolefin structure that is compatible with polyethylene recycling streams. This allows the multilayer film to maintain performance properties through layer structure while ensuring recyclability through material uniformity.
Solution Approach 2:
The patent uses composite materials by combining multiple polyolefin layers with different properties (core layer with >90 wt% ethylene-based polymers, outer layers with different characteristics) to achieve both performance requirements and recyclability. The composite structure allows each layer to contribute specific properties while the overall composition remains recyclable.
2Strength
If multilayer films use a thin first core layer with specific copolymer composition, then tear resistance is improved, but the complexity of film structure increases
Solution Approach 1:
The patent applies local quality by positioning the ethylene-propylene copolymer layer specifically at the core (inner layer) of the multilayer structure, where it provides localized tear resistance enhancement. The copolymer composition (60-95 wt% ethylene, 5-40 wt% propylene) is tailored for this specific location to optimize mechanical performance where it is most needed.
Data Source
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AI summary
Provided are multilayer films including ethylene-based polymers. The multilayer films can be fully compatible with polyethylene recycling streams. The multilayer films include a first outer layer, a second outer layer, and a core, the core including a first core layer that includes an ethyl ene-propylene copolymer. The multilayer films of the present invention can exhibit improved, maintained, or desirable properties, such as high tear resistance, in comparison to existing multilayer film structures that are not fully compatible with polyethylene recycling streams.