XNR-400D

1. Working principle

 

XNR-400D  is a plastic extrusion instrument. It uses a high-temperature heating furnace to make the tested object melt under the specified temperature condition. The test object in this melting state is extruded through a certain diameter hole under a specified load. In plastic production, melt index is often used to express the physical properties of polymer materials, such as fluidity, viscosity, etc. in the melting state. The so-called melt mass flow rate refers to the average weight of each section of extruded samples converted to 10 minutes of extrusion. The unit is (g / 10min), expressed by MFR:

 

MFR=600×m÷t （1）

 

Where: MFR - melt mass flow rate, g / 10min;

 

M - average value of multi-stage sample cut, G;

 

T-Time interval of sample cutting, s;

 

600 - reference time (10min), S.

 

Or: MVR = 42.7 × L ÷ t (2)

 

Where: MVR - melt volume flow rate, cm3 / 10min;

 

L - preset measuring distance of piston movement, mm;

 

T-Time interval of sample cutting, s;

 

42.7 - product of reference time (10min) and piston area.

 

For example, for a group of plastic samples, cut one section every 30 seconds. The weight of each section results in:

 

0.0838g 0.0862g 0.0815g 0.0895g 0.0825g

 

Take the average value m = (0.0838 + 0.0862 + 0.0815 + 0.0895 + 0.0825) ÷ 5

 

=0.0847 (g)

 

Substituting formula: MFR = 600 × m ÷ 30 = 1.694 (g / 10min)

 

The melt index is 1.694g/10min.

 

2. Instrument model classification