Process for surface activation and/or devulcanization of sulfur-vulcanized rubber particles

Abstract

Process for surface activation and / or devulcanization of sulfur-vulcanized rubber particles. In order to break the sulfur bridges and to reduce the sulfur, the rubber particles are treated in a biotechnological manner in a medium with mesophilic anaerobic and / or optionally anaerobic and / or microaerophilic bacteria and / or with one or more enzyme systems of such bacteria. The thus-treated activated rubber particles show improved vulcanization properties in comparison with non-treated rubber particles, and permit the production of better quality articles.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]The present invention is a continuation of U.S. patent application Ser. No. 10 / 551,664, filed on Jun. 21, 2006, entitled “Process for Surface Activation and / or Devulcanization of Sulfur-Vulcanized Rubber Particles,” which is a U.S. National Stage of PCT Application No. PCT / IB04 / 00932, filed Mar. 29, 2004, and entitled “Process for Surface Activation and / or Devulcanisation of Sulphur-Vulcanised Rubber Particles,” which claims priority German Patent Application No. 103 14 893.0, filed on Apr. 1, 2003, having a translated title of “Process for Surface Activation and / or Devulcanization of Sulfur-Vulcanized Rubber Particles.” The entire content of each of the aforementioned patent applications is incorporated by reference herein.BACKGROUND OF THE INVENTION[0002]1. The Field of the Invention[0003]The invention relates to a process for surface activation and / or devulcanization of sulfur-vulcanized rubber particles.[0004]2. Background and Relevan...

AI Technical Summary

Benefits of technology

[0018]The object of the invention, therefore, is to provide a method for surface activation and / or devulcanization of sulfur-vulcanized rubber particles which is carried out substantially at temperatures below 90° C. and avoids the aforementioned disadvantages of microbial oxidation processes.

Problems solved by technology

In addition to the desired oxidation of the polysulfide sulfur, undesired oxidation of the polymer chains (attachment of free radicals) inevitably takes place simultaneously.

This process nevertheless has the following disadvantages—in particular due to the hyperthermophilic characteristic of the archaeon:1. The treatment of the powdered rubber over a lengthy period at a temperature range of 90-100° C. leads to degradation of the polymer chains of the elastomers and thus to deterioration of the significant material technical parameters (tensile strength, elongation at break, abrasion, etc.).2. Due to the high temperature exposure of the powdered rubber, increased rubber constituents are released (plasticizers, carbon black, zinc oxide, chemical protective agents, etc.) which have a toxic effect on the microorganisms and thus restrict the process of desulfurization or lead to a breakdown of the process.3. Carrying out the process at such a high temperature range is uneconomical with regard to large-scale production and of ecological concern (release of toxic materials into the process waste water).