Lightweighting gets a lot of attention in the automotive sector, but the technology benefits numerous other products. One recent example is eyewear. Hong Kong–based Mentor Optical Ltd. has introduced a line of Plasteel eyewear that weighs 9 grams instead of 23 grams, which is common with conventional glasses. Vestakeep-branded polyetheretherketone (PEEK) polymers from Evonik (Essen, Germany) helped to make that happen.
In addition to being lighter than traditional eyeglass frames, Plasteel eyewear is extremely durable and can sustain a 360° bending test without breaking. Because of Vestakeep’s resistance to stress cracking, the material is suited for injection molding very thin components. The eyewear from Mentor Optical can be designed with rim heights as low as 1.6 mm and a thickness at the temple as thin as 0.9 mm.
A patented plastic rim-lock design allows prescription lenses to be easily mounted, preventing damage that may be caused using the traditional "push-through" method for lens insertion.
Plasteel inherits its mechanical properties and performance from Evonik's Vestakeep material, a high-performance thermoplastic polymer suited for producing reliable, long-lasting components for use in the toughest conditions, according to Evonik. In addition to stress-cracking resistance, the polymer has high energy absorption and its ductile behavior can prevent premature deformation and cracks in the frames. The material’s chemical resistance and thermal stability impart biocompatibility and biostability, adds the company.
Plasteel frames are the product of a collaboration between Evonik, Mentor Optical Ltd. and Ngai Hing Engineering Plastic (NHEP). Evonik provided material and product know-how while strategic distribution partner NHEP offered quick local support to Mentor Optical.