Products: Dow showcases two new liquid silicone rubbers

Cleveland, Ohio — Dow Chemical Co. exhibited two new liquid silicone rubbers that the company said add “ground-breaking innovations” to liquid silicone technology.

The new LSRs, unveiled at the International Elastomer Conference, held in Cleveland in October, include:

Silastic LTC 9400 liquid silicone rubbers, which allow for rapid curing at a lower temperature, with flexible applications in the automotive, consumers and electronics industries; and

Silastic 3D 3335 liquid silicone rubber, formulated specifically to combine the performance benefits of silicone rubber with the design and processing advantages of liquid additive manufacturing 3D printing.

While Silastic is a long-standing brand, LTC 9400 and 3D 3335 offer options and advantages to Dow's silicone rubber customers that are unique, according to Gifford Shearer, market manager for silicone elastomers at Dow Consumer Solutions, and John McKeen, the group's TS&D director.

Dow Silastic LTC 9400 cures at 100°C, rather than the typical 150-160°C, Shearer and McKeen said.

This allows combinations of silicones with plastics such as polypropylene and polycarbonates, which couldn't be done before because of high temperatures, they said.

LTC 9400 LSRs are especially suitable for high-volume injection moulding applications and provide fast temperature activation across a wide processing temperature range, according to Dow.

The two-part, easy-to-use LSR materials are supplied as Part A and Part B and mixed in a 1:1 ratio before moulding, the company said.

The low-temperature curing allows overmoulding the LSR elastomers into low-melting-point plastics or other thermally sensitive components, increasing design freedom, according to Dow.

"In addition, with faster cure times at standard, elevated temperatures, cycle time savings can be realised for standard, moulded components," it said.

Other key characteristics of LTC 9400 LSRs include:

Optimised process cycle times with cure-rate acceleration additives;

A self-lubricating, oil-bleeding option for easy component assembly and reliable sealing; and

Improved rheology for higher injection speeds.

Silastic 3D 3335, according to Shearer and McKeen, offers properties comparable to injection-moulded components and transfers easily to injection-moulding processes.

It expands design options and speeds time to market, they said. It allows for fast prototyping, small manufacturing trials of complex parts, creation of customised parts and new designs, and it can be used in applications where typical LSRs are used, they said.

Like LTC 9400, 3D 3335 is a two-part silicone mixed at a 1:1 ratio. It is supplied in a cartridge system, but pails also are available, Dow said.