Multilayer Structures with Compatibilizer for Recyclability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Commercially-produced multilayer structures with polar and non-polar polymer layers have poor recyclability due to incompatibility between the layers, leading to difficulties in recycling processes.
Innovation Solution
Incorporating a high molecular weight, MAH-grafted compatibilizer in the form of an anhydride and/or carboxylic acid functionalized ethylene/alpha-olefin elastomer into the multilayer structure to enhance compatibility between the polar and non-polar polymers, specifically in the first layer and barrier layer, allowing for improved recyclability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional multilayer structures with polar and non-polar polymer layers are used, then barrier properties and stiffness are improved, but recyclability deteriorates due to incompatibility between layers
Solution Approach 1:
The patent introduces a compatibilizer layer comprising a maleic anhydride-grafted polyolefin that acts as an intermediary between the non-polar polyolefin layer and the polar barrier layer. This tie layer contains functional groups that can interact with both non-polar and polar polymers, facilitating compatibility and enabling effective recycling of the multilayer structure while maintaining the required barrier properties.
Solution Approach 2:
The patent employs a composite multilayer structure where each layer is composed of specific polymer materials with distinct properties. The structure integrates a non-polar polyolefin layer, a polar barrier layer (EVOH or PA), and a compatibilizer layer with grafted functional groups, creating a composite material system that achieves both performance and recyclability goals.
2Reliability
If functional polymers like EVOH or PA are used in barrier layers, then barrier properties are improved, but compatibility with polyolefin waste stream deteriorates during recycling
Solution Approach 1:
The patent modifies the chemical parameters of the polyolefin by grafting maleic anhydride functional groups onto the polyolefin chains in the compatibilizer layer. This parameter change introduces polar character to the otherwise non-polar polyolefin, enabling it to compatibilize with the polar barrier layer polymers (EVOH or PA) and maintain composition stability during recycling.
3Strength
If multilayer structures with polar and non-polar polymers are used, then mechanical properties are improved, but dispersibility in recycling process deteriorates
Solution Approach 1:
The compatibilizer layer serves as a mediator that improves the dispersibility of polar barrier layer polymers within the non-polar polyolefin matrix during the recycling process. The maleic anhydride-grafted polyolefin creates compatible interfaces that allow for uniform dispersion and effective reprocessing of the multilayer waste materials.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
Embodiments of the present disclosure are directed to multilayer structures. The multilayer structures may include a first layer and a barrier layer. The first layer may include, based on the total weight of the first layer, from 90 wt.% to 99.5 wt.% of an ethylene/alpha-olefin interpolymer having a density of from 0.945 g/cc to 0.970 g/cc and from 0.5 wt.% to 10 wt.% of a compatibilizer. The compatibilizer may include an anhydride and/or carboxylic acid functionalized ethylene/alpha-olefin elastomer having a density of from 0.850 g/cc to 0.910 g/cc and a melt viscosity of greater than 200,000 cP, when measured at 177C.