Evonik introduces Polyvest ST, an additive to improve silica/silane/rubber interaction

This week at the Tire Tech Expo in Hannover, Germany, Evonik Industries introduced a new product called Polyvest ST that is designed to improve the compatibility between silica, silane, and rubber in tire formulations. Green tire technology, which uses precipitated silicas and rubber silanes like Si 69, already reduces rolling resistance by up to 30 percent relative to carbon-black-filled tires. According to Evonik, the special feature of the new development is this: according to a fundamental principle in the tire industry, known as the magic triangle, any improvement in one of the core properties of a tire— rolling resistance, wet grip, and abrasion resistance—is always at the expense of at least one of the others. Evonik’s new development further improves the compatibility of silica and rubber in combination with Si 69® or Si 266®, thus pushing out the boundaries of the triangle. The press release does not give details on Polyvest ST, but Evonik Polyvest product range consists of a range of “stereospecific, low viscous and unsaponifiable liquid polybutadienes of different chemical compositions,” according to the company’s website.

Here is the press release.