Electron-Beam Peelable Coating for Printed Substrate Recycling
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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 risks from microplastics.
Innovation Solution
A layer formation method using an aqueous composition containing a polymerizable compound that undergoes polymerization with electron beam irradiation, forming a peelable coating layer on substrates, followed by electron beam irradiation to reduce adhesion and facilitate recycling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a photopolymerization initiator excitable by ultraviolet light is used in the aqueous composition, then the coating layer can be formed, but the coating layer cannot be easily removed from the substrate during recycling
Solution Approach 1:
The patent changes the polymerization mechanism from UV-light initiated to electron beam initiated. By using a polymerizable compound that reacts to electron beam irradiation rather than UV light, the coating layer can be formed during printing but removed during recycling through controlled electron beam irradiation, resolving the contradiction between easy formation and easy removal
Solution Approach 2:
The patent introduces an electron beam as an intermediary energy source to control the polymerization reaction. The electron beam acts as a mediator that can be applied selectively during both the printing process (to form the coating) and the recycling process (to remove the coating), enabling controlled transformation of the coating layer's properties
2Reliability
If the coating layer is made firmly adherent to the substrate, then the printed matter is durable, but the substrate cannot be recycled due to difficulty in separating the coating layer
Solution Approach 1:
The patent makes the adhesion property dynamic rather than static. The coating layer's adhesion to the substrate can be changed from strong (during printing) to weak (during recycling) by applying electron beam irradiation. This dynamic transformation allows the same coating layer to serve different functions at different stages of the product lifecycle
Solution Approach 2:
The patent changes the physical and chemical parameters of the coating layer through electron beam irradiation. The irradiation alters the polymerization state and adhesion properties of the coating layer, enabling it to be easily separated from the substrate during recycling while maintaining durability during use
3Ease of manufacture
If conventional printing methods are used on plastic substrates, then the printing process is simple, but the plastic substrate becomes contaminated and cannot be recycled
Solution Approach 1:
The patent extracts the harmful contamination issue by designing a coating layer that can be completely removed from the substrate during recycling. The electron beam irradiation process breaks down the coating layer's adhesion, allowing it to be separated from the plastic substrate, thereby preventing contamination and enabling substrate reuse
Solution Approach 2:
The patent implements a system where the coating layer is temporarily discarded during recycling to recover and reuse the plastic substrate. The electron beam irradiation facilitates the separation process, allowing the coating layer to be removed and the substrate to be recovered for new printing applications
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 easy removal of printed layers from substrates, reducing environmental impact and improving recyclability while preventing substrate damage and odor generation.
Implementation Method 1
an aqueous composition containing water and a polymerizable compound that is soluble in water and that undergoes a polymerization reaction due to irradiation with an electron beam
Implementation Method 2
a polymerizable compound that is soluble in water and that undergoes a polymerization reaction due to irradiation with an electron beam
Implementation Method 3
an irradiation step of irradiating the coating layer formed by using the above layer formation method with an electron beam at a dose in a range of 1 kGy to 150 kGy
Data Source
AI summary
A layer formation method includes: an application step of applying or ejecting, onto a substrate, an aqueous composition containing water and a polymerizable compound that is soluble in water and that undergoes a polymerization reaction due to irradiation with an electron beam; and a drying step of drying the aqueous composition applied or ejected onto the substrate, in which the aqueous composition is free of a photopolymerization initiator excitable by ultraviolet light, and a coating layer, which is peelable from the substrate, is formed on the substrate using the aqueous composition.