25
New Approaches for the Processing and Crosslinking of Special Elastomers
In particular ongoing Engine downsizing and turbo charging in gasoline engines contribute to reduced fuel consumption. However, on the other hand an increased temperature development is observed.
Rubber parts under the hood like turbo charger hoses, seals or gaskets are designed to seal and transport aggressive automotive fluids at severe temperature conditions. In addition a long service life is a basic requirement OEM suppliers have to guarantee.
Due to the described requirements it is reasonable that the classical Sulfur Vulcanization of elastomers lost a big portion of market share in this segment because of insufficient heat ageing stability which finally leads to a failure of the concerned rubber article.
The polymer manufacturers are responding the increased technical demands with new special elastomer grades dedicated to resist higher temperatures and/or aggressive fluids.
In these days, in order to cover highly severe conditions a Peroxide or Amine crosslinking approach is preferred. The most popular polymer types are based on AEM-, (HT) ACM, HNBR or FKM rubber. However, all of them suffer from certain processing drawbacks. In particular bad flow, less heat stability of the added additives, compromised physical properties, worse release performance from metal parts and mold fouling problems in the injection molding process are observed.
The aim of this presentation is to give an overview on the possibilities of an advanced processing combined with a contribution to the crosslinking.
Schill+Seilacher’s latest development in this field is the recently commercialized Struktol HT 600 (DL), a multifunctional additive addressing the peroxide crosslinking process of special elastomers. By its use the physical properties could be orientated into certain directions which is a big advantage in case certain specifications have to be met. Struktol HT 600 (DL) can replace both, conventional processing aids and co-agents. However, it is recommended to balance the dosage in preliminary trials with conventional co-agents. In particular after ageing the (dynamic) properties are significantly stable.
Second focus of this presentation will be on a new product which was developed for Amine crosslinked Special Elastomers. In particular in the injection-moulding process a good release from the mould is a requirement for a stable-running process. If a totally automated Injection Moulding process is interrupted because of insufficient release, the article has to be removed manually which is related to an increased scrap rate and reduced efficiency of the process. It will be demonstrated that the use of a new reactive product could solve such release and operating problems, repectively.
Also, if an additional value could be added to a special elastomer compound in terms of maintained or improved physical properties, this might be an argument to test the new approach.