Melt Flow Index - Manuel

APPLICATION

This machine is designed to conduct measurement in accordance with  ISO 1133, ASTM D1238 and ASTM D336  standards.  It  measures  MFR  <Melt  Flow  Rate>  (g/10min.)  and  MVR  <Melt  Volume Flow Rate> (cm3/10min.) of plastics.

Melt  viscosity  of  thermoplastics  has  a  considerably  large  affect  on  processability  of  plastics  such  as molding and yarn-making and thus measurement of the melt viscosity plays a very important role in the fields  of  research  and  quality  control.    Among  the  various  kinds  of  such  testing  machines  the  Melt Indexer  is  the  most  easy  to  operate  and  is  being  most  widely  used  for  this  purpose.    It  measures volume (MVR) or weight in grams (MFR) of melt polymer that comes out of specified die (orifice) under a constant pressure and constant temperature.

The testing method is of two kinds, namely Method A (Manual operation  cut off method) and Method B  (Automatically  timed  flow  measurement  method  of  measuring  piston’s  descending  speed  by means  of  counter).      Method  A  is  suitable  for  materials  having  melt  flow  rate  in  0.1~25g/10min. (ASTM   method   50g/10min.)   range   and   Method   B   is   good   for   materials   of   melt   flow   rate  0.5~300g/10min. 

In  this  case  the  number  of  grams  of  polymer  extruded  in  10  minutes  from  the  orifice  under  a  load  of  2.16kg and temperature 190°C is indicated by <Melt Mass Flow Rate (MVR)>.    Until now it was also known as <Melt Index (MI Value) > or <Flow Rate and Flow Index>.    The melt flow of plastics depends on  shear  rate,  but  shear  rate  at  the  time  of  molding  is  extremely  large  and  we  should  know  that  the obtained  result  may  not  necessarily  agree  with  the  flow  behavior  in  actual  use.      However,  it  is  being widely used as an effective means for quality control purposes.