From the very beginning of its recycling activities, MAL-PLAST has paid great attention to the quality of its products. Each batch of material coming off the production line is tested for physical properties and polypropylene content. In order to be able to control the quality of our regrinds and regranulates in 2022, we have taken steps to open an on-site Laboratory. Thanks to our efforts and the support of the EU, the next step in improving the quality and continuity of our development became a reality in June 2023.

At the moment, our Laboratory performs determinations of the basic parameters we need to ensure the complete satisfaction of our customers. These include research:

  • Densitie
  • Humidit
  • % content of polypropylene and other materials in the produc
  • MFI/MFR indicator

In addition, both the raw materials we use and all our products are visually assessed for suitability and quality. This type of differentiation is based primarily on an assessment of their combustion behaviour (evaluation of the colour of the flame, the smell on combustion or the way the material burns).

In the near future, we plan to extend the range of tests performed in our laboratory to include impact, tensile strength and tensile modulus determinations. At the moment, this service is provided by external companies with whom we have been working for a long time.

Brief characteristics of the determinations
performed in our laboratory

Determination of plastic density

The density test is performed in accordance with EN ISO 1183-1. It uses Archimedes’ principle (immersion method), according to which the weight of the sample is measured twice. The first time in air, the second time in a liquid, which is most often water, as long as the density of the sample ensures that it is fully immersed (or suitable tools are used to determine the density of a sample with a density less than that of water). For the determination, we use a kit consisting of an Adventurer AX224M analytical balance and a kit for determining the density of solids.

Moisture determination

The test is based on the “standard method for measuring the moisture content of plastics on the basis of weight loss” in accordance with ASTM D6980. We carry out the marking on a high-end KERN DBS-60 weighing machine. The test consists in placing the material in a weight dryer and automatically calculating the % moisture content of the material on the basis of the decrease in the weight of the batch during its heating after selecting the appropriate drying programme.

Determination of the % composition of the manufactured regrinds

For the determination of the content of PP, PE and other plastics in our products, we use the sIRoPAD device manufactured by the German company GUT. The percentage of individual plastics is determined using NIR analysis, and the absorption spectra obtained are compared with a database entered into the instrument’s IT system. Our analyser gives us extensive possibilities to identify individual flakes of the tested plastic and to record all the test results in graphical and textual form.

Determination of MFI/MFR

The purpose of determining the MFR and MVR is to understand the basic processing property of thermoplastics, i.e. the melt flow rate. The determination is carried out on the basis of ISO 1133-1. The test is carried out on a Hydrapress REO-100 plastometer and consists of plastifying a plastic sample and extruding it at a set temperature and load through a nozzle with a defined geometry.