Shrink Sleeve Label Ink Removal Through Preheating and Shredding
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Solution Overview
Problem
The ink layer on shrink sleeve labels applied to PET bottles cannot be efficiently removed, hindering the recycling of these labels and the production of useful pellets.
Innovation Solution
A method involving preheating the shrink sleeve labels to a temperature equal to or higher than the alkaline desorption temperature, shredding them into smaller pieces, and then using alkaline desorption to remove the ink layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the shrink sleeve label is shredded before alkaline desorption, then the ink layer removal efficiency is improved, but the label pieces may curl up in the alkaline solution making ink layer removal difficult
Solution Approach 1:
The label is preheated before shredding to activate the heat shrinkable properties, causing the label to shrink and reduce curling tendency. This preliminary thermal treatment prepares the label for subsequent shredding and alkaline desorption by establishing a shrunk state that resists curling in the alkaline solution.
Solution Approach 2:
The temperature parameter is controlled during preheating to be at or above the alkaline desorption temperature. This parameter change activates the heat shrinkable properties of the label, transforming its physical state to reduce curling and improve subsequent ink layer removal efficiency.
2Stability of the object's composition
If the preheating temperature is set equal to or higher than the alkaline desorption temperature, then the label shrinks effectively reducing curling, but energy consumption increases
Solution Approach 1:
The preheating temperature is optimized to be at or above the alkaline desorption temperature, which is the minimum temperature required to activate the heat shrinkable properties. This parameter setting achieves effective shrinking while avoiding excessive energy consumption that would result from using unnecessarily high temperatures.
3Ease of manufacture
If the ink layer is not efficiently removed, then recycling infrastructure can be used, but useful pellets cannot be fabricated
Solution Approach 1:
The label is processed in a non-aqueous immersion environment during preheating, which prevents premature ink layer removal. This inert environment allows the label to be shrunk and shredded without the ink dissolving, and only after shredding is the label exposed to the alkaline solution that enables complete ink layer removal and pellet production.
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
This method significantly enhances the efficiency of ink layer removal, allowing for effective recycling of the shrink sleeve labels and their components.
Implementation Method 1
preheating the shrink sleeve label including the ink layer
Implementation Method 2
a temperature of the preheating is the same as a temperature of the alkaline desorption or higher than the temperature of the alkaline desorption
Implementation Method 3
removing the ink layer from the shrink sleeve label pieces by alkaline desorption
Data Source
AI summary
Provided is a method of efficiently removing an ink layer. The method of removing an ink layer from a shrink sleeve label includes preheating the shrink sleeve label including the ink layer, shredding the shrink sleeve label after the preheating to fabricate shrink sleeve label pieces, and removing the ink layer from the shrink sleeve label pieces by alkaline desorption. A temperature of the preheating is the same as a temperature of the alkaline desorption or higher than the temperature of the alkaline desorption.