Additive Slipstream Injection in Polymer Melt Processing
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Solution Overview
Problem
Existing methods for adding additives to polymer melts, such as polyester polymers, often expose additives to high temperatures, inhibit catalyst activity, or result in poor mixing, especially when using carriers like ethylene glycol, which can be undesirable during polycondensation reactions.
Innovation Solution
A method involving discharging a polymer melt, solidifying it, and creating a slipstream to introduce additives before solidification, allowing for efficient mixing and minimizing exposure to high temperatures, with the option to use minimal carrier fluids or feed additives through an extruder.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If additives are added to polymer melt during polycondensation using reactive carriers like ethylene glycol, then the additives can be incorporated into the polymer, but the polycondensation reaction is inhibited and extra glycol is added to the oligomer mixture
Solution Approach 1:
The patent applies preliminary action by adding the additive to the polymer melt after polycondensation is substantially complete, rather than during the reaction itself. This timing ensures the additive is incorporated without interfering with the polycondensation process, eliminating the harmful effect of reaction inhibition while still achieving additive incorporation into the final polymer product
Solution Approach 2:
The patent extracts the harmful element (reactive carriers like ethylene glycol) from the additive addition process. By using inert carriers or adding the additive neat without reactive carriers, the method eliminates the source of polycondensation inhibition while maintaining effective additive incorporation into the polymer melt
2Productivity
If additives are exposed to high temperatures during polycondensation, then the polymerization process can proceed, but the additives suffer thermal degradation
Solution Approach 1:
The patent performs the additive addition after the polycondensation reaction is substantially complete, when the temperature can be reduced. This preliminary timing of additive incorporation avoids exposing the additives to the high temperatures required for active polycondensation, thereby preventing thermal degradation while still achieving full polymerization of the base polymer
Solution Approach 2:
The patent skips the high-temperature polycondensation phase when adding the additive. By rapidly transitioning to the post-polycondensation stage for additive incorporation, the method minimizes the time additives are exposed to harmful high temperatures, rushing through the vulnerable period before stabilizing at lower temperatures
3Quantity of substance
If additives are added to polymer melt, then the desired functional properties are achieved, but mixing is poor especially when using carrier fluids
Solution Approach 1:
The patent changes the physical parameters of the polymer melt by controlling temperature and viscosity in the post-polycondensation stage. By maintaining the melt at appropriate temperatures after polycondensation, the polymer retains sufficient fluidity to enable thorough mixing of additives, achieving homogeneous distribution without the need for excessive carrier fluids that would dilute the system
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 ensures effective mixing and minimizes additive thermal degradation, allowing for better control of polymer structure and properties while reducing the need for reactive carriers, thus improving the quality of the final polymer product.
Implementation Method 1
solidifying said discharged polymer melt stream
Data Source
AI summary
A method for adding an additive into a polymer melt, preferably a polyester polymer melt such as polyethylene terephthalate (PET), comprising:a. discharging a polymer melt from a reactor to form a discharged polymer melt stream, andb. solidifying said discharged polymer melt stream, andc. prior to solidification, feeding a portion of the discharged polymer melt stream to a slipstream to form a slipstream polymer melt, andd. feeding an additive into said slipstream polymer melt to form an additive containing slipstream, ande. feeding the additive containing slipstream to a location upstream from the feed location forming said slipstream.