Alcohol-Based Remover for Coating Separation on Plastic
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Solution Overview
Problem
Current methods for removing coatings from plastic articles, particularly those with high weather resistance or primer coatings on polypropylene (PP) bases, face challenges such as incomplete removal, safety concerns with strong alkali removers, and environmental issues with solvent disposal, as well as high energy consumption and equipment costs.
Innovation Solution
A method using a remover formed from monohydric lower alcohols like methanol, ethanol, or 1-butanol, heated to a temperature not exceeding 10°C below its boiling point, to swell and separate the coating from the plastic base without dissolving it, facilitated by shredding and stirring processes, and optionally using a sodium hydroxide solution for enhanced removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If strong alkali remover is used to remove coating, then coating removal efficiency is improved, but safety concerns and environmental issues worsen
Solution Approach 1:
The invention changes the chemical composition parameters of the remover from strong alkali to a formulation containing monohydric lower alcohol (5-50 wt%), dihydric lower alcohol (5-50 wt%), and water (20-90 wt%). This parameter change maintains effective coating removal while eliminating the safety and environmental hazards associated with strong alkali removers.
Solution Approach 2:
The invention uses a biodegradable alcohol-based remover formulation that is environmentally friendly and can be easily disposed of without causing environmental deterioration, replacing the persistent and hazardous strong alkali removers.
2Productivity
If high temperature heating is used to remove coating, then coating removal speed is improved, but energy consumption and equipment costs worsen
Solution Approach 1:
The invention changes the temperature parameter from high temperature (120°C or higher) to a moderate temperature range (40-100°C). The optimized remover formulation achieves effective coating removal at these lower temperatures through chemical action, significantly reducing energy consumption and eliminating the need for expensive high-temperature equipment.
Solution Approach 2:
The invention replaces the thermal-mechanical removal mechanism (high-temperature heating and stirring) with a chemical-mechanical mechanism (remover formulation action combined with mild stirring). The remover chemistry performs the primary removal function, allowing mechanical agitation to be much gentler and energy consumption to be dramatically reduced.
3Manufacturing precision
If alkaline remover liquid is used to remove coating, then coating removal completeness is improved, but base dissolution risk worsens
Solution Approach 1:
The invention changes the chemical nature of the remover from alkaline to alcohol-based. The monohydric and dihydric lower alcohols in the formulation selectively swell and loosen the coating for complete removal while being chemically inert toward the plastic base, thus maintaining base integrity. The pH and chemical composition parameters are specifically adjusted to achieve this selectivity.
Solution Approach 2:
The alcohol-based remover acts as an intermediary substance that mediates between the coating and base. It selectively interacts with the coating (swelling and loosening) without attacking the base, effectively separating the removal function from any potential base damage that would occur with strong alkalis.
4Productivity
If high concentration alkali remover is used, then coating degradation efficiency is improved, but environmental deterioration worsens
Solution Approach 1:
The invention changes the chemical composition from high concentration alkali to a biodegradable alcohol-water formulation. The monohydric and dihydric lower alcohols effectively degrade and remove coatings through chemical action while being environmentally benign, eliminating the environmental deterioration caused by high concentration alkali removers.
Solution Approach 2:
The invention converts potentially harmful strong alkali chemistry into beneficial alcohol-based chemistry that maintains effective coating degradation while being environmentally friendly. The harmful alkaline properties are replaced with beneficial alcohol solvation and swelling properties that achieve the same removal function without environmental damage.
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 approach allows for efficient and safe removal of coatings from coated plastic articles without dissolving the base, enabling high recovery rates and reducing the need for expensive equipment, while minimizing environmental impact.
Implementation Method 1
The remover includes at least one monohydric lower alcohol selected from the group consisting of methanol, ethanol, propanol, and 1-butanol, and swells at least one of the base or the coating
Implementation Method 2
heating the remover to a first temperature, wherein the first temperature is not lower than 25° C. and not higher than a temperature that is 10° C. lower than a boiling point of the remover
Data Source
AI summary
A method and a device for removing a coating on a coated plastic article allow highly efficient removal of a coating from a coated plastic article and recovery of a base after coating removal and a remover. A method for removing a coating on a coated plastic article with a remover includes shredding the article into pieces, immersing the pieces in the remover heated to a second temperature, heating the remover to a first temperature, and stirring the pieces with the heated remover. The remover includes at least one monohydric lower alcohol selected from methanol, ethanol, propanol, and 1-butanol, and swells the base, the coating, or both. The first temperature is not lower than 25° C. and not higher than a temperature 10° C. lower than a boiling point of the remover. The second temperature is not higher than an upper limit of the first temperature.