How to Improve Rubber Compounds

Rubber compounding is a highly complex endeavor that involves many interactions and includes many ways to achieve the target properties and economic goals while maintaining an acceptable trade-off for these characteristics. The purpose of this book is to provide the reader with various experimental ideas that may guide him or her to develop better compounds and solve technical problems.

In the rubber industry, ultimate tensile strength is considered a fundamental material property. This test parameter measures the ultimate strength of the cured vulcanizate. Even though a typical rubber product probably never will be stretched anywhere close to its ultimate tensile strength, many rubber product users still consider it an important indicator of the overall quality of the compound. Therefore, tensile strength is a very common specification property that a compounder typically will need to find a way to meet even though its relevance to the specific product end use is usually poorly defined.

Hot air aging and heat aging resistance are becoming very important today, especially in automotive applications where “under-the-hood” operating temperatures have been increasing and there is more pressure from automotive manufacturers to have rubber parts that last longer (part of the move toward a 150,000-mile car warranty!). Anaerobic heat aging resistance can be quite different from hot air aging resistance. For example, a rubber compound might possess good reversion resistance (anaerobic), yet still be subject to oxidative attack (or vice versa). The type of aging properties that a cured rubber compound possesses is very important in determining how that compound will be classified in accordance with SAE J200/ASTM D2000 for automotive applications.

Sometimes it is necessary to keep the viscosity of a mixed stock low to ensure good processability downstream in the plant.

The factory problem of porosity is very common with many different rubber fabricators and costs corporations millions of dollars each year.

Improving the wet traction of a tire is very important.

The following experimental ideas may improve this tire performance characteristic. Also, all relevant literature sources, including the ones cited below, should be researched and read. Caution: these general experimental ideas may not work in all specific situations. Changes to improve tire wet traction will certainly affect other properties as well, for better or for worse, and this book does not purport to show how these other properties are affected. Also, this book does not purport to address safety and health issues.