The new issue 5/2019 of PU Magazine International has been published!
In this issue you can inform yourself about the forthcoming K 2019 trade fair in Düsseldorf, where many machine manufacturers, raw materials and additive manufacturers as well as system houses and processors of polyurethanes will exhibit.
Featured technical articles are:
- Investigation of the bond strength between injection moulded TPU and a reactive, castable polyurethane mass (PU)
(E. Moritzer, J. Jilg, N. Sibbe, Plastics Technology Paderborn (KTP) - University of Paderborn and Gustav Meister GmbH)
Polyurethanes are one of the most versatile material groups within the plastics processing industry. Their fields of application can be found in a large number of technical and everyday products. A special niche application, which has been available on the market for a long time, is two-component plastic screens, which combine thermoplastic polyurethanes (TPU) with reactive and castable polyurethane compounds (2C-PU system). The TPU screen inserts have the function of classifying and dewatering the sieved material, while the PU mass serves as composite and carrier material. Compared to other soft plastics from the thermoplastic elastomer (TPE) segment, polyurethanes have a particularly high resistance to abrasive media in the recycling, natural stone, chemical and wood processing industries, which is why they are primarily used in plastic screens. In order to quantify the bond between these two soft components (TPU/PU), this paper shows the development of a manufacturing and testing system, since there is no suitable test guideline available for a soft-soft 2C bond.
- A practical look at compression set: Effect of temperature, % deflection and stoichiometry on LFTDI and MDI elastomers
(E. Duckett, S. Seneker, C. Elliott, J. Duckett, Anderson Development Company)
The standard testing method for compression set is ASTM D395. This method was developed in 1934 and optimized to test rubber. The industry standard was to run a sample at 70 °C under 25 % deflection for 22 hours . Even though most polyurethane application conditions are below 70 °C and less than 25 % deflection, this standard continues to be used for polyurethane elastomers. This paper will investigate elastomers of varying composition and stoichiometry and the effect that temperature and % deflection has on compression set. Differences between LFTDI/aromatic diamine cured elastomers and MDI/BDO cured elastomers will be specifically investigated.
- Growing market: use of renewable raw materials for aliphatic PU coatings with high UV resistance
(J. Hoffmann, M. Bielen, Alberdingk Boley GmbH)
Biobased coatings are used more and more, not only in Europe, but worldwide. Discussions about biobased coatings with visitors of a workshop at Alberdingk Boley’s R&D Center showed that demand for UV-stable polyols based on renewable resources is increasing.
- Expandable Graphite: Perfect flame retardant for polyurethane
(S. Schmidhuber, G. Hagel, FoamPartner Germany GmbH and KraussMaffei Technologies GmbH)
With expandable graphite as flame retardant, polyurethane (PU) parts can comply with the strictest fire prevention requirements. However, the shear sensitivity of the material requires a reduction of the mechanical stress during processing to a minimum. Appropriate adaptation of the metering and mixing technology is recommended for this reason.
Further information about the new issue at https://www.gupta-verlag.com/magazines/pu-magazine-international/05-2019.