Profile und andere Elastomerbauteile, die in Fahrzeuginnenräumen eingesetzt werden, unterliegen heute hohen Anforderungen hinsichtlich Geruch und gasförmigen Emissionen bei gleichzeitigem hohen Niveau an mechanischen Daten und guter Lebensdauer. Die Vernetzungseffizienz und das Emissionsverhalten von mono-, di- und multifunktionalen Peroxiden ist im Vergleich zu traditionellen Schwefelvernetzungssystem in EPDM untersucht worden. Eine hohe Vernetzungseffizienz des eingesetzten Peroxydtyps kompensiert teilweise eine hohe Konzentration an flüchtigen Spaltprodukten per Mol Peroxid im Vulkanisat. Insgesamt lässt sich durch den Einsatz von effizienten Peroxiden der Anteil an organischen Emissionen aus einem Elastomerprodukt vergleichsweise bedeutend reduzieren.
In terms of low emission and simultaneously acceptable mechanical values for tensile strength and elongation at break, studies of the emission behavior of EPDM vulcanizates crosslinked with mono-, bi- and multifunctional peroxide systems in comparison to a typical sulfur system for EPDM profiles show that especially the systems TBPC (multifunctional, ''Trigonox 171'') and DHBP (bifunctional, ''Trigonox 101'') produce good results, even if they do not quite equal the VOC and FOG or mechanical values attained by the sulfur reference vulcanizate. In the case of ''Trigonox 171'' most emissions originate from the byproduct DIPP and not from the main component TBPC. So this new developed product looks promising, but there is a necessity of optimization in purity! For the system crosslinked with DHBP in particular, some of the emission values measured were lower than for the sulfur reference vulcanizate, although DHBP has the highest per-mol emissions when compared to the other peroxides. However when the vulcanizates are standardized so as to have an approximately uniform crosslinking density, DHBP benefits from its high crosslinking efficiency, i. e. the molar concentration needed in the rubber compound is relatively low. Despite low crosslinking efficiency, the multifunctional system ''Trigonox 322'' based on DABT and small quantities of TAC as byproduct, which can react as co-activator displays good emissions behaviour. This is due to its complex reaction mechanism with few cleavage products only. In all emissions values, the mono-functional peroxide DCP shows comparatively high values, both in the fogging test to DIN 75201-B and in TDS-GC-MS analyses for determination of the FOG value and the VOC value analogous to VDA 278. Due to the high volatility of peroxide decomposition products in general, tempering is very effective in reducing the value to approx. 20% of the level at outset.
Effect of peroxide crosslinking on the emission behavior of elastomers
Einfluss der peroxidischen Vernetzung auf das Emissionsverhalten der Elastomere
2008
13 Seiten, 8 Bilder, 3 Tabellen, 24 Quellen
Conference paper
English
The comparison of radiation and a peroxide crosslinking of elastomers
Automotive engineering | 2015
|Emission behaviour of peroxide crosslinked EPDM elastomers
Automotive engineering | 2008
|Thermomechanics of Elastomers Undergoing Scission and Crosslinking at High Temperatures
Online Contents | 2003
|Mechanism of peroxide crosslinking of EPDM rubber
Automotive engineering | 2009
|Environmental ageing of elastomers - the duality of crosslinking and chain scissions
Automotive engineering | 2016
|