Momentive: Liquid silicone rubber and speciality silanes
At K 2019, Momentive Performance Materials Inc. showcased its portfolio of Silopren liquid silicone rubber and other silicone elastomer solutions. According to the company, the new self-bonding Silopren LSR 27x9 family addresses the rising demands for hard-soft designs, helps to achieve the bonding between silicone and thermoplastics, reduces assembly steps, and meets various complex design requirements. The products are said to offer primer-less adhesion to many PC, PBT and copolyester substrates in commercial hard-soft combinations.
A highlight at K 2019 was the presentation of a two-component moulding cell for the production of an innovative ‘butterfly’ smartphone-holder prototype. Within a cycle time of 40 s, this cell overmoulded a plastic frame, based on Covestro’s Apec 1745 polycarbonate, directly in a second shot with the new Silopren LSR 2759 from Momentive. The result is a smartphone-holder with very good primer-less adhesion between the PC and silicone rubber, and ready for attachment to a car´s ventilation flap. The entire demo design, set up and implementation was provided by Elmet, which also built the two-shot mould, automation and LSR dosing system Top 5000 P. The setup was implemented on a two-component injection moulding SmartPower 120 machine and robot from Wittmann-Battenfeld.
Furthermore, Momentive presented its speciality silanes, including Tospearl 120 FL spherical beads, that can provide good thermal stability and low surface energy properties, making them candidates to consider for use in BOPP (biaxially oriented polypropylene) films where slip and anti-block properties are required. Used primarily with polycarbonate and acrylic resins, TSR 9000 spherical silicone beads are a versatile additive that can help improve optical diffusion of light. Additional benefits include heat stability and a low refractive index. PEarlene SiPC MB01 is a silicone gum masterbatch, enhanced with a polycarbonate that is used in the extrusion of plastic copolymers and elastomer formulations. Momentive said that its masterbatches can offer improved processability, as well as scratch and mar resistance when used in the compounding or extrusion of certain plastics.