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| Author | Topic: POLYPROP EXTRUSION |
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john green Senior Member Posts: 12 |
posted October 06, 2005 07:30 AM
   
Has anyone experiance with extruding polypropylene on a cast extruder ? I have tried blending pp mfi 3 with pe but have lots of die lines and reduced draw from the die I am going to try 100% pp with a MFI OF 7 any comments would be appreciated John IP: Logged |
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Tom C Moderator Posts: 630 |
posted October 06, 2005 09:55 PM
Some types of PE are compatible with some types of PP. This is a highly researched blend and some searching of the research would likely greatly improve your results. PP grades are offered in the 7mi range for cast film use. Lower MI grades seem to be used for more draw and orientation. ------------------
Tom Cunningham
Extrusion Technical Services www.ExtrusionTechnicalServices.com IP: Logged |
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joeex Senior Member Posts: 10 |
posted October 07, 2005 05:49 AM
John, I am running PP on cast line using 3.2 mfi homopolymer / copolymer blend. What are you adding the PE for is it to soften the sheet or some other reason. What thickness are you trying to achieve ? IP: Logged |
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john green Senior Member Posts: 12 |
posted October 07, 2005 08:19 AM
Hi Joe Actually we normaly run with ldpe lldpe hdpe what I am trying to do is produce film using either 100% pp or a lldpe pp mix to increase strength but the problem is pp does not come back together when split with die lines like lldpe does so I am having to experimient with different mfi IP: Logged |
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pyth Member Posts: 2 |
posted October 29, 2005 10:27 AM
Actualy we have tested it but the big problem is ,when thermofored it is very hard to cut in mould.Actually we are in a plastic cup field so we extrude PP and have tried mixing it with ldpe and pe..processibility is good ..only in cutting have dificulties.. IP: Logged |
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ravi Senior Member Posts: 13 |
posted November 10, 2005 01:37 AM
First try to blend LLDPE only, whose MFI is NEARER to the MFI of base material. Check the recommended processing temperature on the technical sheet of the materials being mixed and select the material with least temperature difference with base material. The problems should be lesser with HDPE. Later add the LDPE if necessary and find out by trials, the maximum percentage that can be blended. Higher the percentage of blending material higher the homogenity problem. So, what percentage are you trying to blend? What are you trying to achieve by blending? what is the end product? IP: Logged |
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john green Senior Member Posts: 12 |
posted November 10, 2005 12:04 PM
What we are trying to do is produce film with pp material which in the past was not possible.How ever recent testing showed an interesting out come we started with a mix of ldpe and pp which instantly showed up every line in our die causing splits in the web which before with pe were not showing on the web so despite previous attempts with just pp we tried again this time output was same as pe and we could produce film the only problem was the web shrinking on width so we are going to try some higher MI Material IP: Logged |
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