Halogen dryer enables easy residual moisture measurement

  • Plastic drying and “the more the better” phenomenon
  • Akro-Plastic and Mettler-Toledo are working on easy and cost-effective residual moisture measurement
  • Halogen dryer enables comparative measurements between KF-method and thermogravimetric method

“Most of the injection molders now use modern drying devices that dry the pellet for several hours before processing it at 80°C. Indeed, very few of them can precisely determine the residual moisture content of the pellet and consequently the optimum processing state of the material”, as Edgar Düvel, Key Account Manager at Akro-Plastic experienced during his several customer visits.

Karl-Fischer-Titration (KF-Method): precise, but expensive

Polyamides, for example, require a residual moisture of 0.02 to 0.1 %, however, the material is often too dry, which among other things, would lead to bad flowability and thus, particularly in case of components with long flow paths or delicate ribs, to insufficient mold filling. This can result at a large number of components in surface appearance problems.  During the production process of plastics and compounds, the manufacturers determine the moisture content of the pellet in the laboratory by means of the Karl-Fischer-Titration (KF-Method). This method is very precise, but also very expensive and moreover, takes too long a time. This has stopped many plastics converters from using this process in their own plants.

Convenient handling of moisture analyser

Convenient handling of moisture analyser (source: Mettler Toledo)

Halogen dryer: simple and easy to operate

Akro-Plastic along with Mettler-Toledo, carries out comparative measurements between the KF-method and the thermogravimetric method for determining the residual moisture by using a halogen dryer. Current test results are promising and a good correlation between the methods is assumed, according to Akro-Plastic. The Halogen-method would thus be a very simple and easy to operate alternative.

“We want to show our customers locally how they can determine the moisture content of the pellet with a measuring device that is easy to operate and an optimally fine-tuned software in an easy, quick and cost-effective way and thus, not only improve the quality of their end-products, but can also optimize their energy consumption”, says Edgar Düvel.

After the correlation tests are completed, the company will present the mobile device HX204 Moisture Analyzer to its customers on-site.


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