Neck-in trouble of PP resin in T-die process

Dear sir.. everyone.
I have a fiendish problem.. The problem is the neck-in trouble of PP in T-die process. What is Melt elasticity or What is Melt strength??
Which one does make an impact on the trouble? In order to decrease the trouble, what should i do..? Please help me....
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More heat, more time, more pressure.
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Melt strength is the resistance of the melt to extension, while melt elasticity is a measure of elastic recovery. Melt elasticity and melt strength are directly related. The higher the melt elasticity, the higher the melt strength. Melt strength are commonly increased by molecular weight, crosslinking or long chain branching or by blending with LLDPE copolymer.
To measure those melt properties one uses typically a Goettfert Rheotens Tensile Tester. The Goettfert Rheotens measures the extensional properties of polymer melts by drawing a vertical melt strand at a constant extension rate. The force needed to elongate the strand is measured and used to calculate other properties of interest, like melt strength and melt elasticity.
For resolving your issue you could either try more die pressure, or to switch to a Higher Melt Strength PP, unless you are using such already ...
Rheotens Test http://www.goettfert.com/images/stories/downloads/produkte/Rheotens_engl.pdf
HMSPP - Hight Melt Strength PP http://www.e-jornalclassificados.com/hmspphome.htm
canizaro wrote:

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