Decolorizing Polyolefin via Isoparaffinic Solvent and Bleaching
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Solution Overview
Problem
Current methods for decolorizing polyolefinic plastics are not effective, as they often damage the molecular structure of the plastic and are not applicable to all types of polyolefins, leading to the need for new technologies that can efficiently remove color without compromising the material's properties.
Innovation Solution
The method involves using isoparaffinic solvents to dissolve polyolefin plastics, adding bleaching agents and filter aids, and performing a hot liquid-solid separation to recover the decolorized polymer, which maintains the molecular structure and physical properties of the plastic.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional solvent methods are used to decolorize polyolefin plastics, then color removal is achieved, but the molecular structure of the plastic is damaged
Solution Approach 1:
The patent changes the chemical parameters of the solvent system by using specific isoparaffinic solvents with controlled molecular weight distributions and adding bleaching agents at optimized concentrations. This allows effective color removal while maintaining molecular structure integrity through controlled chemical interactions that dissolve and reprecipitate the polymer without degradation
Solution Approach 2:
The patent introduces bleaching agents as intermediary substances that mediate between the solvent and the colored polymer. These agents selectively target and remove colorants while the isoparaffinic solvent system maintains the polymer's molecular structure, allowing color removal without direct aggressive interaction with the polymer chains
2Ease of manufacture
If conventional decolorization methods are applied to polyolefin plastics, then color is removed, but the method is not applicable to all types of polyolefins
Solution Approach 1:
The patent develops a universal decolorization system using isoparaffinic solvents that can effectively process multiple types of polyolefin plastics (polyethylene, polypropylene, and their blends). The solvent system and bleaching agent combination is designed to work across different polyolefin chemistries, making the method broadly applicable rather than limited to specific polymer types
3Productivity
If colored polyolefinic plastic material is recycled, then waste plastic is converted into articles, but the recycled granules must be compounded with virgin material to be recolorized
Solution Approach 1:
The patent extracts and removes the colorants from the recycled polyolefin material through selective dissolution and precipitation processes. By using isoparaffinic solvents and bleaching agents, the colorants are separated from the polymer matrix, producing decolorized recycled granules that can be used directly without requiring compounding with virgin material for recolorization
Solution Approach 2:
The patent discards the colorants as separate removable components and recovers the decolorized polymer material in its original form. The process separates and removes pigment particles and colorants from the recycled plastic, allowing the main polymer body to be recovered with its original properties intact and ready for new 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
This method results in a decolorized polyolefin material with low residual solvent content, allowing it to be reused in various applications with properties similar to virgin plastic, and achieving a pigment reduction of over 89%, suitable for use in multiple applications except food packaging.
Implementation Method 1
dissolving said polyolefin plastic material in an isoparaffinic solvent
Implementation Method 2
adding one or more additives selected from bleaching agents
Implementation Method 3
hot filtering said solution on a cellulose filter
Implementation Method 4
hot liquid-solid separation step
Implementation Method 5
removing the colorant, and recovering the polymer
Data Source
Figure 1
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AI summary
A method for decolorizing a polyolefin plastic material comprising the steps of: a) providing said plastic polyolefin material in solid form comprising at least one pigment or at least one filler or a mixture thereof infused into said material, said at least one pigment or filler or mixture thereof imparting color to said polyolefin plastic material; b) dissolving said polyolefin plastic material in an isoparaffinic solvent, c) adding one or more additives selected from bleaching agents and d) submitting the solution obtained in step c) to a hot liquid-solid separation step.