Pelletized Polymer Compositions via Underwater Pelletization
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional continuous processes face challenges in pelletizing low viscosity low molecular weight polymeric materials without incurring additional costs, as they are difficult to form into pellets effectively.
Innovation Solution
A process involving polymerizing alpha-olefins in solution reactors, followed by solvent removal in a devolatilization system, heat exchanger treatment to raise and lower the temperature, and subsequent pelletization using an underwater pelletizer to produce polymer compositions with low solvent content and appropriate viscosity for pellet formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional continuous processes are used to pelletize low viscosity low molecular weight polymeric materials, then the process is simple and cost-effective, but the pelletization is difficult and ineffective
Solution Approach 1:
The patent changes the temperature parameter of the polymer melt by cooling it below its crystallization point before pelletization. This parameter change transforms the low viscosity melt into a higher viscosity state that can be effectively pelletized using conventional equipment, resolving the contradiction between process simplicity and pelletization effectiveness.
Solution Approach 2:
The patent utilizes the phase transition of the polymer from a molten state to a cooled state below the crystallization point. This phase transition increases the viscosity and enables effective pelletization, allowing conventional continuous processes to handle low viscosity polymers that would otherwise be difficult to pelletize.
2Manufacturing precision
If the temperature of the polymer composition is reduced below the crystallization point, then the viscosity increases enabling effective pelletization, but the process complexity increases due to additional cooling requirements
Solution Approach 1:
The patent employs a heat exchanger that serves dual functions: first as a heater to raise the temperature for solvent removal, then as a cooler to lower the temperature below the crystallization point for pelletization. This multi-functionality reduces device complexity while achieving the required temperature control for effective pelletization.
Solution Approach 2:
The patent maintains continuous operation throughout the process, with the heat exchanger continuously adjusting the temperature of the polymer stream. This continuous temperature control enables steady-state pelletization without interrupting the process flow, reducing the need for additional complex control systems.
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 enables the efficient pelletization of low viscosity low molecular weight polymers, achieving a viscosity suitable for pellet formation while maintaining low solvent content and specific molecular weight ranges, thus overcoming the challenges of conventional methods.
Implementation Method 1
a first heat exchanger that raises the temperature of the molten polymer composition
Implementation Method 2
removing heat from said polymer composition having low solvent content in a second heat exchanger to a temperature in the range of equal to or greater than the crystallization point
Implementation Method 3
removing at least a portion of said one or more solvents in a devolatilization system thereby forming a polymer composition having a low solvent content
Data Source
Figure 1
AI summary
The present invention relates to a pelletized polymer composition produced via a process comprising: polymerizing one or more alpha-olefins in one or more solution reactors thereby producing a molten polymer composition comprising one or more solvents; removing at least a portion of said one or more solvents thereby forming a polymer composition having a low solvent content (typically less than 1,000 parts of solvent per million of polymer on a weight basis); removing heat from said polymer composition having low solvent content to a temperature in the range of equal to or greater than the crystallization point of the polymer composition having low solvent content to less than or equal to a temperature in the range of from (the crystallization point of the polymer composition having low solvent content + 20 °C) thereby forming a viscous polymer melt; and pelletizing said viscous polymer melt via an underwater pelletizer thereby forming said pelletized polymer composition; wherein each pelletized polymer composition has diameter in the range of from less than 6 mm.