Reducing moisture levels in a material from 20% to less than 4%.

Not only do customers come to the Polymers Technology Center to develop new compounds, they also ask for our help when tackling a challenge inherent in an existing compound. Together the customer and the Technology Center staff figure out creative ways to meet the difficult requirements needed.

In the following case study, our customer needed to compound two materials that also needed to be underwater pelletized. No problem – the Technology Center has a new state-of-the-art compounder and an underwater pelletizer. Sounds like this will be an easy one – not so fast…

The Problem: The final product needed to have less than 4% moisture but could not be completely dry; somewhere in the 1% moisture level would be ideal. Previous history with this compound showed that it carried as much as 20% moisture out of the centrifugal dryer.

The Solution: The first step of our solution was to reduce the length of the pipe from the cutter to the centrifugal dryer. Secondly, we increased the water temperature to 160° F. These two steps reduced the moisture by 50%, but we still were not below the 4% target.

To further reduce the moisture, we decided to add residence time. We did this by adding a vibrating separator and three conveyors. And that did the trick. The results in 20 different boxes showed an average moisture level of 1.65%. The customer was very happy with the results.