REFLECTION POLYMER MELT PROBE For In-Line Color Measurement

INTRODUCTION

The Reflection Polymer Melt Probe (RPMP) is an accessory invented and developed by Equitech for use with the Equispec Inline Process Spectrophotometer (IPS) (FIG 1). It is designed explicitly for reflected color measurements from a molten plastic stream in an extruder.

The RPMP (FIG. 2) consists of the body or “bolt” that is installed in the extruder and a removable fiber assembly that sends light to and receives light from the sample (FIG 3 & 4). In addition, there are six illumination fibers surrounding a central detection fiber. 

The fiber assembly is typically manufactured to a length of 5 meters; longer fiber runs are achieved using extension fibers to the required length.

The RPMP requires the use of a calibration fixture, black trap, and white master calibration tile (matte finish) to complete the RPMP calibration before a color measurement with the EquiSpec IPS.  In addition, the RPMP must be installed in the extruder in a location with good material flow.

The use of the RPMP provides extruders and compounders the opportunity to monitor in-line and in real-time variables such as:

• Residence time distributions
• Optimization of screw design
• Optimization of extrusion rate
• Optimization of feeder flow rates
• Determination & resolution of feeder issues
• Determination & resolution of blending issues
• Reactive extrusion monitoring
• Measurement of the concentration of chemical additives
• Alarm of off-specification color or additives
• Continuous, real-time quality assurance
• Enable closed-loop control