Brentwood Plastics blog

Melt Fracture in PE film

Posted by Joel Longstreth on Thu, Mar 06, 2014 @ 04:09 PM

Melt fracture a/k/a "sharkskin" or "applesauce" occurs in LLDPE film.

melt fracture polyethylene film LDPE

To say that much has been written on the subject is an understatement.  Entire books and dissertations abut melt fracture have been written by polymer chemists a lot smarter than me.  Still there is not total agreement on the causes.  Personally, I have a hypothesis that it has something to do with susceptibility to degradation in the transition section of the screw.  


Going back to the early days of LLDPE melt fracture was just expected in butene LLD but not Octene.  Carbide advocated a return to shorter L/D ratios for shorter residence time.  This and granular resin never really took off.

No matter the cause, melt fracture results in a very irregular scaly texture to the film.  In most cases, this is considered an undesirable quality because it detracts from the cosmetics.  In a few cases such as forearm protectors it is considered a plus but i don't know why.

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Topics: LLDPE melt fracture

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