Multilayer Heat Shrink Label Using Cyclic Olefin Copolymers
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Solution Overview
Problem
Existing heat shrink label technologies face challenges in effectively labeling items with uneven surfaces, particularly containers with significant diameter variations, as they often fail to provide a tight, uniform fit and are difficult to separate during recycling processes.
Innovation Solution
A multilayer heat shrink label comprising cyclic olefin copolymers with specific glass transition temperature differences and a terpolymer core layer, oriented in one direction to achieve controlled shrinkage, combined with an adhesive layer for secure attachment and easy detachment, and a method involving stretching and heating to fit the item's shape.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional heat shrink label technologies are used, then the labeling process is simple, but the label fails to provide a tight fit on items with uneven surfaces and significant diameter variations
Solution Approach 1:
The patent applies parameter changes by utilizing the glass transition temperature characteristics of cyclic olefin copolymers. The first COC has Tg ≤ 55°C and the second COC has Tg ≥ 60°C, creating a temperature range where the label material transitions from rigid to flexible. This allows the label to conform to uneven surfaces and adapt to diameter variations when heated during the shrinking process, while maintaining structural integrity at room temperature.
Solution Approach 2:
The patent employs composite materials by combining two different cyclic olefin copolymers with distinct glass transition temperatures in a single label structure. This composite approach enables the label to exhibit both rigidity for structural support and flexibility for conforming to complex geometries, resolving the contradiction between maintaining tight fit and adapting to varying diameters.
2Strength
If the label material provides strong adhesion to the item, then the label remains securely attached, but the label becomes difficult to separate during recycling processes
Solution Approach 1:
The patent utilizes parameter changes related to material density and temperature-dependent properties. The label material has a density of 0.94-0.97 g/cm³, which is lower than typical container materials. During recycling, this density difference enables easy separation through flotation or sedimentation processes. The strong adhesion is achieved through the copolymer composition and shrinking fit, while separation is facilitated by the inherent density characteristic of the COC materials.
3Manufacturing precision
If the label is designed to shrink tightly to the item, then a uniform fit is achieved, but the labeling process requires elevated temperature treatment
Solution Approach 1:
The patent applies parameter changes by exploiting the glass transition temperature range of the cyclic olefin copolymers. The first COC (Tg ≤ 55°C) and second COC (Tg ≥ 60°C) create a transition window that allows shrinking to occur at relatively low temperatures (60-80°C). This enables uniform fit achievement without requiring excessive heating, as the material becomes sufficiently pliable within this temperature range to conform uniformly to the item surface.
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 a heat shrink label to conform tightly to items with varying diameters, ensuring a secure fit and facilitating easy separation during recycling by exploiting differences in material density for separation in a washing process.
Implementation Method 1
a glass transition temperature of the first cyclic olefin copolymer and the second cyclic olefin copolymer is between 50 and 90 °C
Implementation Method 2
facilitating easy separation during recycling by exploiting differences in material density for separation in a washing process
Implementation Method 3
heating the label at temperature between 65 and 80 °C so as to form a tight fitting label for the item
Data Source
Figure 1~3
Figure 4
Figure 5~6
AI summary
The invention relates to a heat shrink label (4) and a multilayer face film of the label (4). According to an embodiment multilayer face film is oriented in one direction. The multilayer face film includes at least one layer comprising first cyclic olefin copolymer and second cyclic olefin copolymer and the first cyclic olefin copolymer is different from the second cyclic olefin copolymer. A glass transition temperature of the first cyclic olefin copolymer and the second cyclic olefin copolymer is between 50 and 90 °C. Further the application concerns a combination of a label (4) and an item (8), a method for providing a heat shrink label (4), a method for labelling an item (8) and a method for separating a label (4) from an item (8) labelled.