Aqueous Coating Composition for Peelable Printed Substrates
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Solution Overview
Problem
Plastic products with printed matter are difficult to recycle due to discoloration and adhesion issues, leading to environmental pollution and health concerns from microplastics.
Innovation Solution
An aqueous composition containing a photopolymerization initiator, polymerizable compound, and resin component, which forms a coating layer on non-permeable substrates, allowing for easy peeling and recycling by UV irradiation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a coating layer is formed on a substrate using conventional printing methods, then the substrate can be printed with desired images, but the coating layer becomes difficult to remove and the substrate cannot be recycled
Solution Approach 1:
The patent applies preliminary action by incorporating photopolymerization initiators and polymerizable compounds into the coating layer formulation before application. This allows the coating layer to be designed with specific chemical properties that enable controlled polymerization and subsequent controlled degradation, facilitating easy removal after the printing function is fulfilled
Solution Approach 2:
The patent utilizes parameter changes by controlling the photopolymerization process through UV irradiation. The coating layer transitions from an unpolymerized state (easy application) to a polymerized state (functional integrity), and can be controlled to degrade under specific conditions (easy removal). This chemical parameter transformation enables both strong adhesion during use and controlled detachment for recycling
2Reliability
If the coating layer is made adherent to prevent discoloration, then the printing quality is improved, but the substrate cannot be reused due to strong adhesion
Solution Approach 1:
The patent applies dynamics by designing a coating layer with time-dependent adhesion characteristics. The coating layer exhibits strong adhesion during the printing and usage phase to prevent discoloration, but the adhesion is designed to be reversible and controllable. Through photopolymerization control, the adhesion can be dynamically adjusted from strong (during use) to weak (for removal), enabling substrate reuse
Solution Approach 2:
The patent uses an intermediary mechanism by introducing photopolymerization initiators and polymerizable compounds as chemical mediators between the coating layer and substrate. These intermediaries enable controlled chemical bonding that can be activated and deactivated through UV irradiation, providing reversible adhesion that ensures both printing quality and substrate recyclability
3Ease of manufacture
If conventional printing inks are used on plastic substrates, then the printing function is achieved, but the plastic substrate breaks down into microplastics causing environmental pollution
Solution Approach 1:
The patent applies discarding and recovering by designing a coating layer that can be easily removed and disposed of separately from the substrate. The coating layer contains photopolymerization initiators and polymerizable compounds that enable controlled degradation, allowing the coating to be discarded while the plastic substrate is recovered and reused. This separation prevents microplastic formation by ensuring complete removal of the coating layer without substrate degradation
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 effective removal of the coating layer from substrates, reducing environmental and health risks while maintaining substrate reusability.
Implementation Method 1
The photopolymerization initiator has an absorption wavelength peak in a range of 350 nm or more and 400 nm or less
Implementation Method 2
an absorption wavelength peak in a range of 350 nm or more and 400 nm or less
Data Source
AI summary
An aqueous composition includes: at least a photopolymerization initiator, a polymerizable compound, a resin component, and water, in which the photopolymerization initiator has a solubility of 1 wt % or more in the water and has an absorption wavelength peak in a range of 350 nm or more and 400 nm or less, the polymerizable compound has a solubility of 1 wt % or more in the water and has plural polymerizable reactive functional groups, and the aqueous composition is in an emulsion state where the resin component is dispersed in the water.