Recycling Elastomer Toughened Thermoplastics via Solvent Separation
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Solution Overview
Problem
Recycling of thermoplastic polymers toughened with elastomer domains/particulates, such as HIPS and ABS, is challenging due to the inability to achieve the same properties as virgin polymers, leading to substantial variability in recycled materials.
Innovation Solution
A method involving the selective dissolution of thermoplastic polymers in an aprotic solvent, followed by the addition of a smectite mineral powder with an average particle size of at most 2 micrometers, and application of a force to separate elastomeric particulates and insoluble additives, allowing for the recovery of pure thermoplastic and elastomeric particles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If mechanical pulverizing is used to recycle thermoplastic polymers, then the recycling process is simple, but the recycled plastics fail to achieve the same properties as virgin polymers and introduce substantial variability
Solution Approach 1:
The patent extracts and separates the elastomer domains from the thermoplastic polymer matrix through selective dissolution. The thermoplastic polymer is dissolved in a solvent, allowing the elastomer domains to be separated by filtration or centrifugal decanting, thereby obtaining pure thermoplastic polymer for recycling without the variability introduced by mechanical pulverizing
Solution Approach 2:
The patent changes the physical state of the thermoplastic polymer from solid to dissolved state in a solvent, enabling selective separation based on solubility parameters. This parameter change allows the thermoplastic polymer to be separated from elastomer domains and insoluble additives, achieving consistent recycled polymer properties
2Manufacturing precision
If dissolution and physical separation methods are used, then the separation of elastomers and additives is improved, but the process complexity and energy consumption increase
Solution Approach 1:
The patent introduces a solvent as an intermediary substance that selectively dissolves the thermoplastic polymer. This intermediary enables the separation of elastomer domains and insoluble additives from the thermoplastic polymer through filtration or centrifugal decanting, achieving high separation purity while maintaining reasonable process complexity
Solution Approach 2:
The patent replaces purely mechanical pulverizing with a combination of dissolution and physical separation methods. The solvent-based dissolution approach substitutes for mechanical breaking, enabling cleaner separation of components and higher recycling quality without excessive mechanical complexity
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 the reuse of recycled materials with properties comparable to virgin polymers, enabling their application in various polymer blends and enhancing the properties of polystyrene or styrene-acrylonitrile type polymers.
Implementation Method 1
dissolving the thermoplastic polymer of the TPP in a solvent comprised of an aprotic solvent forming a solution
Implementation Method 2
applying a force to the solution to separate the elastomeric particulates and insoluble additive particles from the solution
Implementation Method 3
separate the elastomeric particulates and insoluble additive particles from the solution to form a separated system
Implementation Method 4
mixing therein a separating powder comprised of a smectite mineral having an average particle size of at most 2 micrometers
Data Source
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AI summary
Toughened thermoplastic polymers such as acrylonitrile butadiene styrene comprising polymers (ABS) may be recycled by a method comprising dissolving the toughened thermoplastic polymer of in an aprotic solvent in the presence of a separating powder comprised of a smectite mineral having a small size (desirably submicron) and separating insoluble additives, elastomer particles and the separating powder by applying a force, which may be gravity, and recovering the separated thermoplastic polymer. The recovered elastomer and thermoplastic polymer may then be reused in the same type, similar or differing plastics avoiding degradation typically found when recycling toughened thermoplastic polymers.