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12.0 MOLTEN ExTRUDATE
12.1 TESTING PRINCIPLE
The extrudate from a spinneret or bleed point is checked by collecting molten polymer then testing it
WITHOUT FURTHER DRYING.
The polymer MUST be transferred to the PET Plus barrel using a procedure that ensures that the
polymer does not come into contact with any external air. The Sample Melt Pot is designed for this
purpose.
12.2 SAMPLE MELT POT
This is a cylindrical metal block containing a PTFE insert and two tight fitting PTFE end caps.
The top of the pot has a longer stem and has a conical opening. The bottom of the pot is shaped to
fit onto the top of the PET Plus barrel.
WARNING: Hot surface! Wear heat protective gloves.
12.3 USING THE SAMPLE MELT POT
Before using the sample melt pot, ensure that the top and bottom PTFE caps are a tight fit on the unit
and that the sample melt pot is clean and dry.
Remove the top cap and using heat resistant gloves, hold the pot under either a sample bleed point
or as close as possible to the spinneret face or the die of the extruder to collect a sample of extrudate.
When filling from a bleed point, allow the polymer to run into the pot until it is almost full then replace
the top cap.
When filling from a spinneret, the sample should be allowed to spill over the whole top portion of the
pot.
Quickly trim off the excess polymer with a pair of scissors so that the sample is wholly contained in
the hollowed top of the pot.
Withdraw the pot containing the sample and allow the sample to solidify a little, forming a skin.
Push the polymer into the base of the pot using a suitably sized stainless steel rod (the barrel
cleaning tool).
Repeat the sampling procedure until the pot is almost full and then replace the top plug.
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