Dow Medical Solutions, a business unit of the DowDuPont Specialty Products Division has introduced two new liquid silicone rubber (LSR) technologies to support a broader range of rigid plastic substrates for overmolding applications. These new elastomeric products give designers and manufacturers greater options for creating differentiated devices with improved safety and durability.

The two grades include a low-temperature cure (LTC) LSR and a self-adhesive, LTC LSR. Thanks to specialized formulations, they can be overmolded – using two-component injection molding or insert molding – onto heat-sensitive materials including, but not limited to, copolyesters. Use of copolyester is desirable to designers because of the material’s resistance to harsh chemicals in cleaners and disinfectants.

Another advantage of these new LSRs is improved rheology, helping to optimize processing versus more traditional materials.

Gary Lord, Dow’s strategic marketing director said the materials are a reflection of Dow’s goals to anticipate market needs. In medtech, he said, that future is in connected medical devices, for example. The expanded capabilities of the material allow device designers to explore new plastics for their needs, such as temperature sensitive materials.

The materials also offer OEMs an opportunity to enjoy the benefits of faster cure without compromises. “Some manufacturers might be concerned with a shorter pot life of the material, or with the yellowing that often accompanies fast cure products.” Lord said those issues have been addressed. The materials don’t show a tendency to yellowing and the processing time doesn’t have to change. “We wanted our customers to enjoy all the benefits of the material, without the detriments.”

The latest material lines are as follows:

QP1-33X0 is an LSR that delivers low-temperature cure, so that is can be used with heat-sensitive substrates, such as copolyesters. They allow fast injection speeds but maintain low injection pressure.

QP1-5040 is a self-adhesive LSR that provides strong durable primerless adhesion to copolyester, as well as a low-temperature cure if it is needed for processing requirements. It is suitable for two-component and insert-molding processes.