The new product expands WACKER’s ELASTOSIL® LR 3072 product line to include a material with high elastic recovery and extraordinarily low compression set. This means that when a molded part made from the silicone elastomer is compressed and then relaxes, deformation is kept to a minimum thanks to its elasticity and elastic recovery.
The compression set and thus long-term deformation of vulcanized parts made of ELASTOSIL® LR 3072/50 are only ten percent after 22 hours of storage at 125 degrees Celsius. They also retain their function at high temperatures. In addition, cured rubber products made from ELASTOSIL® LR 3072/50 remain flexible and elastic at temperatures as low as -50 degrees Celsius. The new liquid silicone rubber grade is thus ideal for sealing applications in the engine compartment or car body.
With a Shore A hardness value of 50, cured rubber products made from the new oil-bleeding silicone are harder and, as a result, somewhat more rigid than existing grades in this product line. ELASTOSIL® LR 3072/50 reliably seals cable bushings and connector housings with lamellar radial seals, where the housing halves are designed to have a gap.
As a markedly shear-thinning, rapidly curing compound, the new liquid silicone is suitable for use in highly automated injection molding processes. Because it is formulated to be self-adhesive, ELASTOSIL® LR 3072/50 bonds to a number of thermoplastics, such as polyamide (PA) and polybutylene terephthalate (PBT), which are frequently used as the hard component of two-component molded parts. The silicone forms an outstanding bond without a primer coat – even on several metals. This means that the liquid silicone rubber can be molded directly onto these types of substrates in an injection-molding machine, provided the machine and the mold technology are suitable. The result is a fast, affordable means of mass producing thermoplastic/silicone-elastomer or metal/silicone-elastomer composite parts.
Once it has cured and adhesion has developed, ELASTOSIL® LR 3072/50 forms a thin film of silicone fluid, which lubricates the surface of the rubber. This means, for example, that customers can easily thread a cable through an injection-molded, single-wire seal made of ELASTOSIL® LR 3072.