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| Author | Topic: Tie layer bonding |
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peterturk Senior Member Posts: 6 |
posted February 02, 2010 04:54 PM
  
We are having an issue with a tri-layer coextrusion where we cannot get our (Plexar) tie layer to bond to one of the 2 materials of the tubing construciton. The Plexar is bonding to the HDPE but not to the Pebax. This is a new issue and we have not observed this in the past. We're trying all the obvious process related trouble shooting as well as different lots of Pebax to no avail. Any ideas???? IP: Logged |
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Tom C Moderator Posts: 977 |
posted February 02, 2010 05:07 PM
Have you checked your melt temperatures? Adheasion is temperature related for these materials. ------------------ Tom Cunningham www.ExtrusionTechnicalServices.com IP: Logged |
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peterturk Senior Member Posts: 6 |
posted February 02, 2010 05:14 PM
We've tried everything, and all the obvious! We've gone up and down on temerature profiles, checked our RTD's to confirm they are working and calibrated. We run a hot water bath and we've gone up & down on those temperatures. We've tried modifying our pressure profiles. Tried running the product on 2 different lines. tried changing out (resin) lot of Pebax. We were curious as to whether the Plexar could be an issue. We don't have a replacement lot available. It does, however, bond to the HDPE. Could moisture affect the Plexar? We did try drying it but that made no difference. This is a new issue to a product that we have made for years without any issues. It has us stumped! IP: Logged |
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Tom C Moderator Posts: 977 |
posted February 02, 2010 06:15 PM
Since you have pretty much ruled out the line, HDPE and the Pebax as the problem, time to be some different Plexar. In my experinces with Pebax, it transitions from a rubbery melt to a fluid melt above some critical temperature. I would make sure you have reached that temperature. ------------------ Tom Cunningham www.ExtrusionTechnicalServices.com IP: Logged |
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