PET Multilayer Security Card Structure for Easier Recycling
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Solution Overview
Problem
Existing security cards, particularly those with metal-containing layers, are difficult to recycle due to the use of multiple polymer types like PVC and PET, which are chemically resistant and require separation, leading to environmental disposal issues and wear and tear challenges.
Innovation Solution
A multilayered card structure with at least one aluminum-containing layer covered by a PET layer, and all other polymer-based layers composed of PET or PET-G, simplifying recycling by eliminating the need for layer separation and enhancing wear and tear resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple polymer types (PVC and PET) are used in security cards to provide different functional properties, then the card performance and security features are improved, but the recyclability deteriorates due to the need for layer separation
Solution Approach 1:
The patent merges multiple polymer layers into a single PET-based multilayer structure. Instead of using different polymer types (PVC and PET) that require separation during recycling, all layers are made from the same PET polymer, allowing the entire card structure to be recycled as a single unit without complex separation processes.
Solution Approach 2:
The patent applies homogeneity by using the same PET polymer material for all layers of the security card, including the base layer, metal-containing layers, and protective layers. This homogeneous composition eliminates the need for layer separation during recycling, as all layers can be processed together through standard PET recycling methods.
2Strength
If PVC is used in security cards due to its robustness and chemical resistance, then the card durability is improved, but the environmental impact worsens due to difficulty in recycling and potential hydrochloric acid liberation
Solution Approach 1:
The patent changes the material parameter from PVC to PET for all card layers. PET provides similar or superior chemical resistance and durability while being environmentally benign during recycling, eliminating the hydrochloric acid liberation issue associated with PVC decomposition and burning.
Solution Approach 2:
The patent converts the harmful environmental impact of PVC recycling into a benefit by using PET instead. PET is naturally recyclable without releasing harmful chemicals, transforming the recycling process from a harmful activity (releasing HCl) into a beneficial one that closes the material loop sustainably.
3Reliability
If metal-containing layers with optical effects are added to security cards, then the security and aesthetic properties are improved, but the recyclability deteriorates due to the complexity of separating metal layers from polymer layers
Solution Approach 1:
The patent merges the metal-containing layers with the PET polymer layers into a single integrated structure where all layers are made from the same recyclable material. The metal layers are incorporated within the PET matrix, allowing the entire structure including metal elements to be recycled together without complex separation processes.
Data Source
AI summary
The present disclosure relates to a multilayered card structure comprising at least one aluminum-containing layer covered by a first polymer-based layer which is a poly(ethylene terephthalate) (PET) layer. Further polymer-based layers of the multilayered card structure except of potentially present adhesive layers comprise glycol-modified PET (PET-G) or PET. The multilayered card structure may be a security document.