Acrylic Adhesive Recycling Through Solvent-Free Solid-Phase Hydrolysis
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Solution Overview
Problem
The recycling of acrylic pressure-sensitive adhesive waste is hindered by its poor handleability and processability due to a cross-linked structure, and the use of organic solvents for swelling increases treatment liquid requirements, leading to higher costs and reduced yield.
Innovation Solution
A solid phase reaction using high shear force devices like planetary mixers or kneaders to relax molecular chains without solvents, enhancing contact between the acrylic pressure-sensitive adhesive and alkaline compounds for hydrolysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If organic solvent is used to swell the pressure-sensitive adhesive, then the molecular chain is relaxed and hydrolysis reaction is enhanced, but the treatment liquid quantity increases leading to higher cost and reduced yield
Solution Approach 1:
The invention extracts and removes the organic solvent from the hydrolysis system, achieving the desired molecular chain relaxation and hydrolysis reaction enhancement without requiring large quantities of treatment liquid. The solid-phase reaction approach eliminates the need for solvent-based swelling while maintaining reaction effectiveness.
Solution Approach 2:
The invention introduces a solid-phase reaction medium that acts as an intermediary between the pressure-sensitive adhesive and alkaline compound, enabling efficient contact and reaction without requiring organic solvent. This mediator facilitates molecular chain relaxation and hydrolysis while avoiding the drawbacks of solvent-based systems.
2Ease of operation
If organic solvent is used to swell the pressure-sensitive adhesive, then the molecular chain is relaxed, but the cost of treatment liquid and energy for recovery increases
Solution Approach 1:
The invention extracts the organic solvent from the system, achieving molecular chain relaxation through solid-phase reaction mechanisms that do not require solvent-based swelling. This eliminates the need for energy-intensive liquid recovery processes while maintaining the desired operational effectiveness.
Solution Approach 2:
The solid-phase reaction system enables self-service molecular chain relaxation through direct contact between reactants in a solid state, eliminating the need for external solvent addition and subsequent energy-consuming recovery operations. The system achieves its own objectives without requiring additional energy input for liquid management.
3Adaptability or versatility
If treatment liquid is used for swelling, then the alkaline compound can be mixed with organic solvent, but the yield of target product decreases due to product remaining in recovered liquid
Solution Approach 1:
The invention removes the organic solvent from the reaction system, enabling direct solid-phase contact between the alkaline compound and pressure-sensitive adhesive. This extraction eliminates the problem of product contamination in recovered liquid while maintaining reactant mixability through solid-state diffusion and contact mechanisms.
Solution Approach 2:
The solid-phase reaction medium serves as an intermediary that enables effective mixing and contact between reactants without requiring organic solvent. This mediator facilitates reactant interaction while preventing product dissolution in liquid phases, thereby maintaining high target product yield.
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
This method shortens reaction time, increases yield of hydrophilic polymer, and produces high-purity alcohol efficiently, with reduced environmental impact.
Implementation Method 1
hydrolysis of the side chain with an alkaline compound has been investigated
Implementation Method 2
a method involving using an organic solvent having high affinity with the acrylic pressure-sensitive adhesive, which is hydrophobic, to swell the pressure-sensitive adhesive
Data Source
AI summary
Provided are methods of producing, from an acrylic pressure-sensitive adhesive, a hydrophilic polymer serving as a recycled acrylic polymer that may serve as a raw material for a recycled pressure-sensitive adhesive, and an alcohol serving as a by-product of a hydrolysis reaction, without substantially using a treatment liquid such as a solvent. A method of producing a hydrophilic polymer according to an embodiment of the present invention is a method of producing a hydrophilic polymer from an acrylic pressure-sensitive adhesive, the method including a reaction step of subjecting the acrylic pressure-sensitive adhesive and an alkaline compound to a solid phase reaction. A method of producing an alcohol according to an embodiment of the present invention is a method of producing an alcohol from an acrylic pressure-sensitive adhesive, the method including a reaction step of subjecting the acrylic pressure-sensitive adhesive and an alkaline compound to a solid phase reaction.