- Background
- What we're looking for
- What we can offer you
- Q&A
We are a global leader in packaging solutions, with a strong focus on innovation and sustainability across plastics and polymer processing.
Polymer degradation refers to the breakdown of polymer chains, leading to a reduction in molecular weight. In polyester hydrolysis, heat and moisture break ester bonds, leading to inconsistent part quality. Recycled plastic degrades more readily than virgin plastic, due to contamination catalyzing degradation. Injection molding further degrades the plastic via heating (280–320°C), shear forces, and sudden pressure changes.
In injection molding, polymer pellets are melted and mixed in a heated barrel, then injected through a hot runner and nozzle into a mold cavity. The material rapidly fills the mold, takes its final shape, and solidifies as it cools. Throughout this process, degradation can occur; particularly when the polymer experiences high shear stress.
Currently, polymer degradation is not measured in real time during injection molding.
The ability to monitor molecular weight at key points in the process would help to eliminate 'out-of-specification' products and reduce the need for rework. Since molecular weight correlates with viscosity at a given temperature, monitoring viscosity in real time could offer a way to detect degradation during injection molding.
We are looking for in-line technologies to assess polymer molecular weight. These may include in-line rheometers, viscometers, or sensors using pressure differentials, sonic methods or other approaches. Proposed solutions should operate within the ~1.5-second injection window, which includes (1) injection acceleration, (2) injection speed plateau, and (3) injection deceleration into hold. The goal is to correlate in-line measurements of the polymer's properties to either molecular weight or solution intrinsic viscosity (SIV).
- Pressure differential sensors
- Rheometers (in-line)
- Sonic or ultrasonic sensors
- Viscometers (in-line)
- Provides real-time measurements within the ~1.5-second injection window
- Adjusts for temperature fluctuations in the polymer melt
- Operates at high temperatures (280-320°C) and supports a design pressure of 2000 bar
- Integrates within the nozzle, which cannot exceed 17 cm in length (the nozzle tip accounts for 2 cm of that length)
- Correlation of molecular weight to solution intrinsic viscosity (SIV) for easier interpretation by polymer engineers
- Off-line equipment unless it is fed from the extruder and can operate autonomously
- Solutions requiring manual operation to transfer material
- Systems that cause additional polymer degradation
The Q&A is now closed.
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