Performance of Green, Tire Derived, Recovered Carbon Black

Major product development challenges for rubber chemists and engineers have always been processability, performance, durability and cost.  Today designers also add "end of product life" considerations to their lists of product development considerations.  The tire industry has been working in a concerted effort on end of life issues since the early 1990s in North America.  More recently Europe has forced the issue by banning land filling of tires.  Up to now the focus of end of life efforts for tires has been directed at finding any alternatives to land filling.  The result is that today more than 85% of the tires find a second life other than landfill disposal.  Most of these tires in the USA are used as tire derived fuel in cement kilns, paper mills and power plants.  With the issue of tire land filling nearly eliminated in the USA, the recycling industry is refocusing its efforts on developing higher value applications for scrap tires in order to recapture more of the inherent value of the materials (polymers, chemicals, fillers) individually or collectively.

One of these options is the recovery of basic materials through the DEPolymerization^™ of the elastomers and the subsequent separation of all the organic content from the remaining minerals.  The recovered mineral solids, D-E Black Normal 0 false false false MicrosoftInternetExplorer4 ^®, consists of about 80% carbon black.  The original structure of the recovered carbon black remains intact.  The result is reinforcement comparable to virgin carbon black in sulfur and peroxide cured elastomers.  The performance comparisons of recovered carbon black to virgin carbon black demonstrate it is a viable, green product alternative to medium reinforcing furnace carbon blacks and low reinforcing thermal carbon blacks.  The paper highlights the performance differences as well as the similarities between the recovered and virgin blacks.

In terms of social benefits of DEPolymerization, the recovered reinforcing blacks have a substantially lower carbon foot print than do virgin carbon blacks.  This is because no fuel oils or gases are used as raw materials to produce them.  In fact the process generates liquid and gas products that can be used as fuel in addition to recovering black reinforcing agents.  Producers can claim recycled content for the articles they produce with compounds containing the recovered blacks.  As an “end of life” use alternative for scrap tires, DEPolymerization provides a net fuel value 40% greater than using the tires as a direct fuel source.  The paper briefly reviews the data supporting these green aspects of the technology.