Momentive Launches New LSRs

With a focus on requirements of modern mobility concepts at K 2022, Momentive Performance Materials will present the latest developments in LSRs, including flame-retardant grades, grades for thick-walled parts, and an advanced self-lubricating LSR.

 ▪  LSR grades NL6830FR and NL6850FR, both in dark gray, meet the UL94-V0 requirements at 1 mm thickness. With Shore A hardnesses of 35 and 45, respectively, they reportedly combine balanced yet very good mechanical properties with low compression set. Possible applications therefore include seals in the intake area of combustion engines, collective seals and O-rings, for example for use in sensor technology and in the drive area of electric vehicles requiring flame resistance.

▪  Momentive’s new third generation of its LTC-LSR (Low Temperature Cure Liquid Silicone Rubber) cures at even lower temperatures than the development grade presented at Fakuma 2021. This allows the mold temperature to be lowered even further while maintaining the same short heating time, thus saving energy. This reportedly can contribute to more sustainability through reduced energy consumption and enables combinations with compounds containing temperature-sensitive formulation components. Alternatively, it is now possible to almost halve the crosslinking time compared with a standard LSR, such as Silopren LSR 2050. Subsequent annealing is not necessary.

At K 2022, Momentive will be demonstrating the processing of the new LTC-LSR on a Victory 100-120 injection molding machine from Engel Austria GmbH. In this process, a fully automated mold with cold runner and valve gate system from ACH Solution GmbH is used to produce thick-walled, translucent tea light holders as giveaways that resemble cut glass in appearance.

 ▪  Silopren LSR 2725/40 is a further developed, self-lubricating grade. It enables the cost-efficient production of rigid-soft composites in which engineering plastics including PBT are overmolded, for example molded parts with integrated sealing or damping. Because Silopren LSR 2725/40 forms good initial adhesion to the substrate very quickly, short cycle times reportedly are possible. Full adhesion is achieved during subsequent storage at room temperature. At the same time, a migration process takes place, which gives the LSR surface its self-lubricating property that facilitates assembly processes. The material is resistant to high temperatures and flexible at low temperatures, combines good dielectric and mechanical properties and can be easily colored.