Recyclable Packaging Laminate With EVOH Oxygen Barrier
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Solution Overview
Problem
Conventional plastic wraps used for food packaging are not recyclable and do not effectively extend the shelf life of food products while meeting durability and printability requirements.
Innovation Solution
A packaging laminate comprising multiple polymeric layers, including a first layer of polypropylene copolymer and a second layer of low density polyethylene (LDPE), linear low density polyethylene (LLDPE), and/or high density polyethylene (HDPE) resin with a coextruded ethyl vinyl alcohol (EVOH) compatibilizer, which can be recycled by extrusion and pelletization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional plastic wrap is used for food packaging, then the packaging can be produced and used, but it is not recyclable and does not effectively extend shelf life
Solution Approach 1:
The patent uses a multilayer composite structure consisting of polypropylene copolymer layer, polyethylene resin layer, and EVOH barrier layer. Each layer serves a specific function: the polypropylene provides durability and printability, the polyethylene provides flexibility and sealability, and the EVOH layer provides oxygen barrier properties to extend shelf life. The composite structure enables the packaging to meet multiple requirements simultaneously while maintaining recyclability through proper material selection and layer design.
Solution Approach 2:
The patent introduces an EVOH (ethyl vinyl alcohol) barrier layer as an intermediary between the outer polypropylene/polyethylene layers and the food product. This intermediate barrier layer specifically addresses the oxygen transmission issue without requiring changes to the outer structural layers, allowing the packaging to extend shelf life while maintaining its original durability and recyclability characteristics.
2Strength
If conventional plastic wrap is used, then the packaging can be manufactured, but it does not meet durability and printability requirements while being recyclable
Solution Approach 1:
The patent employs a composite material system where the polypropylene copolymer outer layer provides superior durability, tear resistance, and printability, while the polyethylene resin layer maintains flexibility and processability. The specific combination of these materials in controlled thickness ratios ensures the packaging meets strength requirements without compromising recyclability, as both materials are thermoplastics that can be processed through standard recycling streams.
Solution Approach 2:
The patent applies different material properties to different layers of the packaging structure. The outer polypropylene layer is optimized for durability and printability with higher crystallinity and tensile strength, while the inner polyethylene layer is optimized for flexibility and sealability. This local differentiation of material qualities allows each layer to perform its specific function optimally while the overall structure remains recyclable.
3Reliability
If a multilayer laminate structure is used to extend shelf life, then oxygen barrier properties are improved, but the packaging complexity increases
Solution Approach 1:
The patent uses a three-layer composite structure with specific material selections that balance barrier performance with structural simplicity. The EVOH layer provides the oxygen barrier function, while the polypropylene and polyethylene layers provide structural support and processability. By limiting the structure to three essential layers with well-defined functions, the patent achieves effective oxygen barrier performance without excessive complexity that would hinder manufacturing or recycling.
Solution Approach 2:
The patent segments the packaging into three distinct functional layers: an outer polypropylene copolymer layer for durability and printability, a middle polyethylene resin layer for flexibility and sealability, and an inner EVOH layer for oxygen barrier properties. This segmentation allows each layer to be optimized for its specific function while maintaining overall structural integrity and recyclability through standard processing methods.
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 laminate meets USDA and FDA standards for food packaging, is durable and printable, extends shelf life, and is recyclable, with a residual oxygen level of 2.65% or less over 52 weeks.
Implementation Method 1
a second layer, constituting an inner layer of the packaging laminate, comprising a linear low density polyethylene (LLDPE) resin with a coextruded ethyl vinyl alcohol (EVOH) film barrier
Data Source
AI summary
Disclosed herein are compositions and methods related to a packaging laminate comprising: a first polymeric layer formed form a composition including polypropylene copolymer and/or a high density polyethylene (HDPE) resin; and a second polymeric layer formed from a composition including a high density polyethylene (HDPE) resin, a linear low density polyethylene (LLDPE) resin, a low density polyethylene (LDPE), and/or LDPE/HDPE copolymer with a coextruded ethyl vinyl alcohol (EVOH) and compatibilizer. Recyclable packaging containers formed of the packaging laminates are also disclosed.