Multilayer Shrink Label Film Separation and Recyclability
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Solution Overview
Problem
Current labeling technologies face challenges in recyclability, particularly in separating labels from containers without leaving residues, and require materials that exhibit controlled shrinkage for both transportation and application temperatures, while maintaining printability and ease of separation.
Innovation Solution
A monoaxially stretched multilayer film structure comprising a core layer of ethylene and butyl acrylate copolymer, with skin layers of propylene terpolymer, allowing for controlled thermally induced shrinkage and improved recyclability by ensuring low shrinkage at transportation temperatures and high shrinkage at application temperatures, along with enhanced printability and floatability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If adhesive labels are used on plastic containers, then labeling information can be provided, but separation of labels from containers during recycling becomes difficult and leaves residues
Solution Approach 1:
The label is designed as a separate removable component that can be easily detached from the container during recycling. The pressure-sensitive adhesive layer allows the label to be applied to the container but also enables easy removal without leaving residues, thus extracting the labeling function while eliminating recycling contamination.
Solution Approach 2:
The label structure is designed to facilitate discarding the label separately from the container during recycling processes. The specific layer composition and adhesive properties enable the label to be removed and discarded independently, allowing the container material to be recovered pure for recycling.
2Object-generated harmful factors
If heat-shrink labels are used to reduce adhesive, then label separation improves, but controlled shrinkage at different temperatures becomes challenging
Solution Approach 1:
The film composition is engineered to exhibit different shrinkage behaviors at different temperature ranges. The specific polymer blend and layer structure enable the film to have minimal shrinkage at transportation temperatures (maintaining label stability) while exhibiting controlled high shrinkage at application temperatures (enabling tight fitting), thus controlling the shrinkage parameter across different temperature conditions.
3Adaptability or versatility
If multilayer film structures are used to improve functionality, then labeling performance enhances, but recyclability and separation difficulty increase
Solution Approach 1:
The label is constructed as a multilayer film with distinct functional layers (base layer, adhesive layer, release layer) that can be easily separated from each other and from the container. This segmentation allows each layer to perform its specific function while enabling complete separation during recycling, thus maintaining functionality while reducing recycling complexity.
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 efficient separation of labels from containers, maintains print quality, and ensures effective shrinkage for tight fitting on containers, while being recyclable and environmentally friendly.
Implementation Method 1
the films should be suitable for disposable labels, printable to convey product information and easily separable from the labeled articles... heat-shrinked labels, shrink sleeves and roll-fed shrink sleeves
Implementation Method 2
it is desirable to obtain films used for labeling, which may comprise a relatively low thermally induced shrinkage in temperatures during transportation, where the temperature may rise up to 60°C, but a high thermally induced shrinkage in higher temperatures used in manufacturing of labels
Data Source
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AI summary
The invention relates to providing a method for obtaining a multilayer film for thermally inducible shrink labels, products thereof and use of such products.