As you know, one of the common causes of defects of plastic products is the high humidity of the feedstock. Silver plating on the surface, streaks, uneven staining, bubbles inside the product … All this – the result of excessive moisture in the granulate. It found a very effective way to fight against this scourge – pre-drying material. But if hygroscopic plastics (polyamides, ABS, PET, and many other engineering plastics) to be dried on a mandatory basis, the polyolefins, even poverhnostnouvlazhnennye need in this process step is not always the case. But how fast and with sufficient precision to determine whether the dry material is fed to the production?
B. Machinist, director of “Koch Technik RUSSIA” (Nizhny Novgorod)
Currently, the technology, determining moisture content, often simply weigh incoming material for precision scales. It is simple, but not an accurate way. The German company Brabender Messtehnik GmbH & Co. KG polymers developed specifically for modern device AQUATRAC®-3E for determining the residual moisture content (see. Photo). The accuracy of measurement of humidity of the material – to the fourth decimal place! Measuring time – up to 20 minutes!
The principle of operation is to measure the hydrogen partial pressure generated by the chemical reaction of the starting material with calcium hydride. Test material is poured into a measuring vessel made of stainless steel, it is placed a reagent portion, and then the vessel is sealed and installed in the capsule device AQUATRAC®-3E. Next on the display indicates the type of material and its exact weight. Receptacle with calcium hydride material and is evacuated, heated to a certain temperature and reaction begins. The whole process of measuring the moisture content of the granulate is completely automated and takes place without any additional intervention. Reagent kit – calcium hydride – enough for about 500 measurements, it is non-toxic and therefore does not require costly disposal.
Residual moisture analyzer AQUATRAC®-3E (photo: Brabender Messteshnik)
After 20 minutes, the device shows the moisture content of the material as a percentage. In addition, the measurement results can be displayed on a connected printer and print a protocol with the following data:
date and time of measurement;
material type;
batch number;
weight dose, g;
residual moisture,% …
And even then, you can make a decision – to dry or to dry.
In the production there are different situations: sometimes it is necessary to assess whether quality stuff comes out of the dryer, is it possible to start the production of the material in advance, to make measurements of the material moisture after storage outdoors or in a cold room. Manufacturers of automotive components require the conduct formal statistical indicators of quality of incoming material to the customer’s auditors, in many companies there is a laboratory of the input control of raw materials, including polymers.
The company Werner Koch Maschinentechnik GmbH (Mr. ispringen, Germany), which produces including plastics dryers, one of the first in Europe ordered AQUATRAC®-3E device for its production. “The need for AQUATRAC®-3E device due to permanent control of the quality of our dryers with different materials,” – says Edward Resch, Production Manager dryers Koch-Technik. – “This ensures our customers high performance of our equipment.”
Therefore, the need for rapid and accurate control of polymer humidity is very relevant. Not surprisingly, AQUATRAC®-3E device from Germany, demonstrated for the first time in Russia at the International Exhibition “Interplastica 2014” at the joint stand of Koch Technik companies and “FORMOTRONIK” enjoyed a genuine interest in the polymer industry professionals. Now measure the moisture of the material can be carried out in the laboratory of the company “Koch Technik RUSSIA” in Nizhny Novgorod, where the set AQUATRAC®-3E device, and our specialists will answer your questions.
Then, no longer a question – “to dry or dry?”.
«To Dry or not to Dry: That is the Question»
V. I. Maschinistov
Technical capabilities of the new AQUATRAC®-3E device developed by the Brabender Messtehnik and intended for quickly and exact definition of residual moisture in plastics are described.