Multilayer Packaging Sheet with Water-Soluble Separation Layer
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Solution Overview
Problem
Existing plastic packaging materials, particularly multilayer materials, face challenges in achieving desired mechanical, optical, and barrier properties while ensuring recyclability and safety, as they often require thermal recycling, which is environmentally undesirable, and colored materials complicate mechanical recycling due to dye migration and color separation issues.
Innovation Solution
A three-layer sheet material is developed, with a water-soluble or water-disintegrating middle layer containing a functional component of water-soluble polymers and/or water-swellable polymers, allowing easy separation and recycling, and transparent outer layers for protection and visibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multilayer materials are used to achieve desired mechanical, optical, and barrier properties, then packaging performance is improved, but recyclability deteriorates due to thermal recycling requirements
Solution Approach 1:
The packaging is divided into multiple layers with distinct functions: an outer layer for protection, a middle colored layer for branding and UV protection, and an inner layer for barrier properties. The critical innovation is that these layers are connected by a water-soluble tie layer that allows easy separation during recycling, enabling mechanical recycling of each layer individually while maintaining packaging performance during use.
Solution Approach 2:
The tie layer undergoes a parameter change based on environmental conditions: it remains intact and provides strong adhesion between layers during normal packaging use, but dissolves in water during recycling processes. This conditional parameter change enables the material to switch between providing structural integrity and enabling easy separation.
2Adaptability or versatility
If colored materials are used for packaging design and advertising purposes, then visual appeal is improved, but mechanical recycling deteriorates due to dye migration and color separation issues
Solution Approach 1:
The colored layer is extracted as a separate, removable component in the recycling process. The water-soluble tie layer acts as a release agent that allows the colored middle layer to be easily separated from the clear outer and inner layers, preventing dye migration and color contamination in the recycled materials while maintaining visual appeal during product use.
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 solution enables high-quality packaging with desired properties, safe for contents and consumers, while minimizing environmental impact through efficient recyclability by dissolving the colored layer during recycling, separating the layers effectively.
Implementation Method 1
the first layer consists of a first material, the first material comprising at least 50 wt% of a functional component based on the weight of the first material, the functional component consisting of one or more water-soluble polymers and/or one or more water-swellable polymers
Implementation Method 2
the functional component consisting of one or more water-soluble polymers and/or one or more water-swellable polymers
Data Source
AI summary
The present invention is directed to sheet material comprising at least a first layer, a second layer, and a third layer, wherein the first layer is arranged in between the second layer and the third layer, wherein the first layer consists of a first material, the first material comprising at least 50 wt% of a functional component based on the weight of the first material, the functional component consisting of one or more water-soluble polymers and/or one or more water-swellable polymers, such that the first layer is a water-soluble layer or a water-disintegrating layer; and wherein the first layer comprises a transmission haze ≥ 1.5 % determined according to ASTM D 1003, and/or the first material comprises a coloring agent. Furthermore, the invention is directed to a packaging container or flexible composite comprising the above sheet material. Additionally, the present invention is directed to a method for recycling the above sheet material, the above packaging container, or the above flexible composite, comprising the steps of: - shredding the sheet material, the packaging container, or the flexible composite to flakes, granulates and/or a powder, - exposing the flakes, granulates and/or or powder to an aqueous washing solution; - separating solid components from the aqueous washing solution.