Posts: 28
From:germany
Registered: Nov 2006

posted May 24, 2007 10:24 AM            

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Dear All,

At the moment we mix the Basis Silicone Material and then make granulate from the materail. During Granulation we mix talcum so that the granulate doesnt stick to eachother. Then the granulate is fed in the extruder and then we extrude. After extrusion we have found some Talcum agglomerate in the Extrudate which damages our final product. Does anyone have some solution to solve this problem. How can i overcome this problem.
Thanks in advance.

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Posts: 852
From:Brodheadsville, PA USA
Registered: Jun 2001

posted May 24, 2007 12:33 PM            

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I would first check to see that the talc did not already contain agglomerates.

Some talcs are blended with materials that reduce agglomeration. Check with your supplier. Sometimes you can mix in an powdered metallic salt lubricant.

Typically agglomerates are formed at high pressure and are difficult to break up. Some add screens to increase back pressure for more mixing or to filter the agglomerates.

Try reducing the amount of talc being used.

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Best Regards,

Tom Cunningham

www.ExtrusionTechnicalServices.com

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Posts: 28
From:germany
Registered: Nov 2006

posted May 24, 2007 02:16 PM            

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thanks tom for your quick reply. At the moment we are having little talc in our silicone but still we have some problems..
Could you suggest me some materials that can be employed in talc to stop agglomeration. It would be better if these materials are already in use by some customers and found better results in their output products.....

Thanks in advance....

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Posts: 852
From:Brodheadsville, PA USA
Registered: Jun 2001

posted May 24, 2007 06:51 PM            

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Try coating the talc with zinc stearate or sodium stearate, 1%. These work with plastics, I'm not sure about silicone.

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Best Regards,

Tom Cunningham

www.ExtrusionTechnicalServices.com

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