Wash-Off Label Primer Layer for Caustic Soda Detachment
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Solution Overview
Problem
Existing adhesive labels are not easily removable from surfaces during conventional washing processes, such as those using hot dilute caustic soda, which is a challenge for the beverage industry where container reuse and recycling are common.
Innovation Solution
A pressure-sensitive wash-off label with a specific layer structure comprising a print layer, a face film layer made of thermoplastic polymer, a primer layer that dissolves or disperses between the adhesive and face film layers when exposed to caustic soda, and an adhesive layer that becomes inactive to facilitate detachment, allowing for easy removal during washing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a conventional adhesive label is applied to a container surface, then the label provides decoration and information display, but the label cannot be easily removed during conventional washing processes
Solution Approach 1:
The label is segmented into multiple functional layers: a face film layer, an adhesive layer, and a primer layer. The primer layer acts as a release agent that can be selectively removed during washing, allowing the face film to detach from the container surface while the adhesive remains on the container for potential reuse.
Solution Approach 2:
The label's adhesion properties are changed by exposing it to washing conditions (hot dilute caustic soda). The washing process alters the chemical state of the primer layer, reducing its adhesion strength and enabling label removal. This parameter change allows the label to transition from a strongly adhered state to a easily removable state.
2Ease of operation
If the label is made removable during washing, then the label can be removed during conventional washing processes, but the label may not adhere properly to the surface
Solution Approach 1:
The label structure is segmented into distinct functional layers with the primer layer serving as a controlled release mechanism. This segmentation allows the label to maintain strong adhesion during application while enabling easy removal during washing, resolving the contradiction between application ease and removal ease.
Solution Approach 2:
The primer layer acts as an intermediary between the adhesive layer and the container surface. It provides initial adhesion for proper label application but can be selectively removed during washing to enable label detachment, thus mediating between the requirements for strong adhesion and easy removal.
3Reliability
If the label uses strong adhesive to ensure proper sticking, then the label adheres well to the surface, but the label cannot be removed without damaging the surface or leaving residue
Solution Approach 1:
The label is segmented into layers where the primer layer can be selectively removed during washing. This segmentation ensures that the adhesive remains on the container surface without face film attached, preventing surface contamination while maintaining reliable adhesion for proper label application.
Solution Approach 2:
The face film layer is extracted or removed from the adhesive during the washing process. The primer layer facilitates this extraction by being removed first, allowing the face film to detach cleanly from the adhesive and container surface without leaving residue, thus eliminating surface contamination.
4Ease of operation
If the label is designed for easy removal during washing, then the label can be removed during conventional washing processes, but the washing liquid cannot be reused for long periods
Solution Approach 1:
The primer layer is extracted or removed during the washing process, allowing the washing liquid to be regenerated. By removing the soluble primer layer, the washing liquid maintains its effectiveness for longer periods, extending its reuse period while still enabling easy label removal.
Solution Approach 2:
The primer layer is discarded during washing, allowing the washing liquid to be recovered and reused for longer periods. The face film and adhesive are separated, with the adhesive remaining on the container for potential reuse, thus reducing waste and extending the functional life of washing resources.
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
Enables efficient and residue-free removal of labels from surfaces, enhancing the recycling process by allowing containers to be reused and recycled without damage or contamination, and allowing the same washing liquid to be used for a longer period.
Implementation Method 1
the primer layer is configured to detach the adhesive layer from the face film layer through dissolving or dispersing the primer layer between the adhesive layer and the face film layer
Implementation Method 2
the primer layer is configured to detach the adhesive layer from the face film layer through dissolving or dispersing the primer layer
Implementation Method 3
when the label is exposed to a washing liquid comprising caustic soda and having temperature in the range of 60-90 °C
Implementation Method 4
the adhesive layer comprises removable pressure sensitive adhesive, which exhibits tackiness, which is arranged to be inactivated or deadened, when the label is exposed to the washing liquid
Data Source
Figure 1~3
AI summary
The invention relates to a wash-off label structure comprising a primer layer, which is arranged to detach an adhesive layer from a face film layer of the label, when the label is exposed to a washing liquid. The invention further relates to use of the wash-off label for labelling and a labelled article. Still further a method for removing a wash-off label is disclosed.