'Highly Efficient' Purging Agent for Blow Molding Polyolefins

A new purging agent designed to make resin formulation or color changeovers more efficient by purging out melt flow channels quickly has been developed by Techmer PM, Clinton, Tenn. Purging agent PFM117632 is also said to reduce waste and enhance sustainability by saving energy and water and significantly reducing scrap and labor.

The company has seen the product reduce purging time for HDPE dramatically--from several hours to a fraction of that for tough color changes. Results can vary based on factors such as the type of equipment, the color, the processing parameters, and the usage rate. Techmer PM says that PFM117632 also can be used on PP lines.

Said Steve Smith, rigid packaging manager, “This technology is a game changer, especially considering it only takes a couple of pounds of our masterbatch compared to other compounds on the market. We set out to develop an FDA-grade purge system specifically for extrusion blow molding equipment because those machines are notoriously difficult to clean out.”

A major packaging blow molder has experimented extensively with this new concentrated product. Using a Bekum H-121 blow molding machine, the processor added just 2 lb of PFM117632 to the machine at a letdown ratio of just 5% while purging purple HDPE resin to a clean, natural color. It slashed its purging time to just 12 min.

The company says it ran purging tests with six additional colors, and all had similar results. The product is designed for maximum processing temperatures of 500 F (260 C).