Polyolefin Molar Mass Fractionation via Temperature Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current plastic recycling methods face challenges such as high energy consumption, CO2 emissions, and the need for high-pressure processes, which are costly and difficult to operate continuously, while also struggling to produce virgin-like polymers with defined physical properties suitable for various applications.
Innovation Solution
A process for separating polyolefin fractions by molar mass fractionation, involving the use of non-polar solvents like n-alkanes to dissolve polypropylene and polyethylene at specific temperatures and pressures, allowing for the separation of polyolefin fractions with defined physical properties suitable for injection molding and compounding applications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If chemical recycling (solvolysis or thermochemical processing) is used to degrade polymeric structure, then feedstocks for petrochemical industry can be obtained, but total energy input is significantly higher and CO2 emission occurs
Solution Approach 1:
The patent changes the temperature parameter during dissolution to selectively dissolve polyolefin fractions with specific molecular weights. By controlling temperature ranges (e.g., 80-120°C for lower MW fractions, 120-160°C for higher MW fractions), the process separates polyolefin fractions without requiring high-energy thermal degradation, thus reducing energy input while maintaining feedstock recovery capability
Solution Approach 2:
The patent segments the polyolefin material into different molecular weight fractions through sequential dissolution at different temperatures. Each fraction can be separately processed and used for different applications, enabling selective feedstock recovery without complete degradation, thereby reducing overall energy consumption
2Ease of manufacture
If high-pressure processing is used in solvent-based recycling, then polymer dissolution can be achieved, but investment costs increase and continuous operation becomes difficult
Solution Approach 1:
The patent changes the pressure parameter to atmospheric or low pressure conditions while achieving effective polymer dissolution through controlled temperature ranges. This eliminates the need for high-pressure equipment and complex safety systems, reducing investment costs and enabling continuous operation without the operational difficulties associated with high-pressure processes
3Productivity
If mechanical recycling with separation steps is used, then polymer type enriched fraction can be obtained, but product quality remains relatively poor and does not allow food contact or high performance applications
Solution Approach 1:
The patent changes the temperature parameter to achieve selective dissolution based on molecular weight and polymer type. By controlling temperature ranges, the process produces fractions with defined molecular weight distributions and high purity (≥95% polyolefin content), enabling food contact and high performance applications while maintaining high productivity
4Productivity
If continuous high-pressure process is designed, then processing efficiency can be improved, but design complexity increases and operational safety becomes more difficult
Solution Approach 1:
The patent changes the pressure parameter to atmospheric or low pressure conditions, simplifying the process design and removing safety concerns associated with high-pressure continuous operation. The process maintains high productivity through controlled temperature ranges and sequential dissolution steps that can be implemented in simple, safe, continuously operable equipment
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 process efficiently separates polyolefin fractions with specific molecular weights and rheological properties, enabling the production of high-quality recycled polymers suitable for diverse applications without the need for high-pressure processes, reducing energy consumption and environmental impact.
Implementation Method 1
contacting the solid polymer material mixture with a non-polar solvent comprising at least one n-alkane comprising from 5 to 10 carbon atoms, to form a first composition (C1) comprising the solid polymer material mixture and the solvent; heating the first composition (C1) at a first dissolution temperature (T1) in the range of 80 to 120° C.
Implementation Method 2
heating the first composition (C1) at a first dissolution temperature (T1) in the range of 80 to 120° C. and a first pressure (P1) in the range of 0.1 to 1.1 MPa abs. for a first period (M1) of from 5 min to 2 h
Implementation Method 3
A process for separating polyolefin fractions from solid polymer material mixtures by molar mass fractionation
Data Source
AI summary
The present invention generally relates to a process for separating polyolefin fractions from solid polymer material mixtures by molar mass fractionation. The present invention also relates to polyolefin fractions obtained by the process and the use of these fractions in the manufacture of an article.