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 Extrusion, Twin Screw
 Looking for Purge Material For Lab Twin Screw
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guido1165 Senior Member Posts: 6 |
posted May 25, 2005 08:38 AM
  
I need some help in finding some new purging material for our twin screw extruder. Currently we use natural PE or whatever we are pushing through it, or CelSpan. I am looking for something that is a little more friendly for the extruder. IP: Logged |
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2beeps Moderator Posts: 94 |
posted May 25, 2005 06:15 PM
If you extrude PVC (mainly rigid) in your twin screw, here's a purge formulation that I have used countless times---pushing out the rigid PVC compound,until screws are empty,shutting down with purge left in the head and die. Upon restart, after a preheat of the head/die, the new PVC extrusion pushes out the purge, for a clean start! PVC-K65-67----------------------100parts This formula can be blended in a high intensity mixer---to 120C,cooled, and stored IP: Logged |
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colorsolquimica Member Posts: 1 |
posted July 13, 2005 04:56 AM
Hi guido, we are using this solution for our 32mm 40L/D co-rotating extruders on small batches LDPE MFI-70 masterbatch manufacturing with relatively good results. Inmediately after masterbatch production , we put into the extruder LDPE MFI 70 so there is a MFI consistency with end of previous batch. After that we put some parafine oil mixed with DOP or DINP directly on top of screws ( depending on previous color from 100cc to 500 cc, this helps removing organic pigments and solvent dyes from screws) After that we put a mixture of LDPE MFI 2 70% + CaCO3 30% into the extruder( if you are concerned about wear , you can reduce CaCO3 to 10%and reduce screw speed , our extruders screws speed is 400-600 rpm on production and 200-300 rpm when cleaning ). This mixture is more or less 10 kgs on total weight but deppends on how dirty was the extruder at the end of the masterbatch production. When mixture comes out the extruder completely white , we add LDPE MFI-70 and it is ready for next masterbatch batch production. All this process is made without removing die plate for strand pelletizers process. For underwater GALA pelletizers we always have to remove the die plate for claning operation. Hope this might help you someway. IP: Logged |
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George Member Posts: 1 |
posted July 13, 2005 11:24 PM
I found a product that is the best purge compound I have ever used. It is called Ultra Purge. You can find out more information on Ultra Purge at www.ultra-purge.com Ultra Purge is quick, easy, non abrasive and ready to use. I found Ultra Purge to work as adverised. Iam using Ultra Purge in hot runner syatems and through my blow mold accumulator and heads. It works great. Let me know what you think about it. IP: Logged |
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