Stimuli-Responsive Release Liner for Adhesive Recycling
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional packaging materials, including labels, pose challenges for recycling and reuse due to the presence of non-removable release liners, which hinder the recycling process and contribute to waste accumulation.
Innovation Solution
A layered construction incorporating a stimuli-responsive polymer that reacts to non-ambient stimuli, allowing for the removal and recycling of layers, such as a release liner or adhesive, by depolymerizing in response to specific triggers like heat, light, or chemicals, enabling the separation of layers and facilitating recycling or reuse.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional label construction with a release liner is used, then the adhesive is protected from premature bonding, but the release liner cannot be removed and recycled, creating waste
Solution Approach 1:
The release liner is made with a stimuli-responsive polymer that changes its bonding properties in response to specific stimuli (heat, light, chemicals). Under normal storage conditions, the polymer maintains low bonding to protect the adhesive. When recycling is needed, applying the appropriate stimulus causes the polymer to change its bonding characteristics, allowing clean separation of the release liner from the adhesive layer for independent recycling.
2Ease of operation
If a release liner is included to protect the adhesive, then the adhesive functions properly during storage, but the release liner must be disposed of in the waste stream
Solution Approach 1:
The release liner's bonding properties are made dynamic rather than static. The stimuli-responsive polymer allows the release liner to transition between a protective state (low bonding during storage and use) and a separable state (high bonding change when stimulus is applied). This dynamic behavior enables the same material to serve its protective function during manufacturing and use, then facilitate easy separation during recycling without requiring different materials for different stages.
3Loss of substance
If the release liner is made removable for recycling, then waste is reduced, but the adhesive bonding strength may be compromised
Solution Approach 1:
The bonding strength parameter of the release liner is made changeable through stimulus response. During normal use, the polymer maintains optimal bonding strength to ensure reliable adhesive attachment. When recycling is required, applying the specific stimulus (heat, light, or chemical) causes the polymer's bonding parameters to change, enabling clean separation without compromising the adhesive's bonding strength during its functional service life.
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 allows for the efficient removal and recycling of packaging components, reducing waste and promoting sustainability by enabling the separation of layers without damaging the underlying materials, thus enhancing the recyclability and degradability of packaging materials.
Implementation Method 1
the functional layer includes a stimuli-responsive polymer... the stimuli-responsive polymer reacts to at least one specific, non-ambient, stimuli selected from the group consisting of base, acid, oxidizing agent, reducing agent, non-ionizing radiation, ultrasound, acid derived from a photoacid, ultraviolet light, infrared light, visible light, heat, and combinations thereof
Data Source
AI summary
Layered constructions, such as those used in pressure sensitive adhesive constructions and release liner constructions, are disclosed having a functional layer that is capable of removal. Methods of utilizing the layered constructions are also disclosed.