Laser Date Coding on Recyclable PE EVOH Film
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Solution Overview
Problem
Laser date coding, particularly CO2 laser coding, is ineffective on polyethylene (PE) films used in food packaging, making it difficult to visually discern the dates even in good lighting.
Innovation Solution
A flexible laminate packaging film is developed, comprising a polyethylene (PE) film layer and a thin ethylene vinyl alcohol (EVOH) layer, where the laser date coding is created in the EVOH layer, ensuring the packaging is readily recyclable.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If laser date coding is applied to polyethylene (PE) film, then date coding is attempted, but the coding is difficult to visually discern
Solution Approach 1:
The packaging film is segmented into multiple functional layers: a polyethylene (PE) layer for recyclability and barrier properties, and an ethylene vinyl alcohol (EVOH) layer specifically for laser date coding. This segmentation allows each layer to perform its optimal function - the PE layer maintains recyclability while the EVOH layer provides effective laser coding capability.
Solution Approach 2:
The EVOH layer acts as an intermediary between the laser coding process and the final date code visibility. The EVOH layer is specifically suited for laser etching and creates a visible contrast that enhances date code readability, while the PE layer provides the recyclable substrate.
2Loss of information
If a multi-layer laminate film is used to enable effective laser coding, then date code readability is improved, but recyclability may be compromised
Solution Approach 1:
The invention changes the material composition parameters of the film laminate, specifically using polyethylene (PE) and ethylene vinyl alcohol (EVOH) layers. This parameter change enables both effective laser coding (through the EVOH layer's susceptibility to laser etching) and recyclability (through the PE layer's properties and absence of problematic materials like polypropylene or PET).
Solution Approach 2:
The packaging film uses a composite material structure combining PE and EVOH layers. This composite approach allows the PE layer to provide recyclability and barrier properties, while the EVOH layer provides effective laser date coding capability, achieving both requirements simultaneously.
3Quantity of substance
If the EVOH layer is made thin to maintain recyclability, then packaging material efficiency is improved, but laser coding depth may be reduced
Solution Approach 1:
The invention optimizes the EVOH layer thickness parameter to balance coding depth requirements with material efficiency. The EVOH layer is made thin (no greater than 5% of total film thickness) but remains sufficiently thick to provide effective laser etching and visible date codes, achieving both material efficiency and coding effectiveness.
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 effective and readable laser date coding on PE film packaging while maintaining the packaging's recyclability, as the EVOH layer is susceptible to laser etching, enhancing date code readability.
Implementation Method 1
the laser date coding being created in the EVOH layer... the EVOH layer is susceptible to laser etching
Data Source
AI summary
A packaged food product includes a food product in packaging formed from a polyethylene film laminate body having a main polyethylene (PE) film layer and an ethylene vinyl alcohol (EVOH) layer. The packaging is laser date coded, with the laser date coding being established in the EVOH layer. Of the overall packaging, the ethylene vinyl alcohol layer is quite thin, generally having a thickness which is no greater than 5% of a thickness of the food packaging. The entire food packaging is readily recyclable, particularly by being at least essentially void of any polypropylene polymers and polyethylene terephthalate. The EVOH layer can be the outermost layer of the packaging, such as with the packaging being limited to just the PE and EVOH layers, or the packaging can include one or more other layers, such as cold seal, tie and/or ink layers.