Industrial Implementation of the Integrated Continuoius Mixing iCOM®

Continuous mixing processes are generally much more cost-efficient than discontinuous processes. Nevertheless the rubber industry mainly uses batch processes utilizing internal mixers or two roll mills. Despite of numerous attempts for the implementation of continuous mixing processes a general breakthrough in large scale productions has not been achieved yet. The main reason for this is the fact that continuous mixing processes are much more error-prone (dispersion of fillers, scorch, dosing errors, etc.) than batch processes. In addition to that there was no reliable inline quality control tool for black rubber compounds. Standard methods for the quality control of rubber compounds like vulcameter curves or Mooney viscosity measurements take time (≥ 10 min.), furthermore, these tests are not representative. Less than 0.01 wt.-% (10 g out 100 kg) are measured.

To achieve an optimal production process VMI Holland BV and Rhein Chemie Rheinau GmbH have developed the iCOM®-process [1]. In this process the final mixing of the base compound together with the vulcanization system can be performed in a single production step. Additionally, the compound can be screened by using a gear pump strainer combination. The vulcanization system is added in form of a polymer bound additive package. Due to the pre-dispersion of the powdered additives and the immediate incorporation of the granules a homogeneous final compounds with a high quality is produced at reasonable output. The process safety is guaranteed by the inline quality process control Rhenowave® [2]. Rhenowave® uses ultrasonic waves to measure the distribution of the crosslinking chemicals with zinc oxide as a marker substance. In addition Rhenowave® provides information on the amount and the dispersion of fillers in the compound.

Rhein Chemie Rheinau GmbH has set-up two extrusion lines for the production of bladder compounds using the integrated continuous mixing process iCOM®. The feasibility of the iCOM®-process at large scale is demonstrated using the inline process control Rhenowave®. In addition to that Rhenowave® can be used in many other applications to determine the quality of various rubber compounds.

1. A. Schröder, L. Wawrzinski, V. Meenenga, S. Wachter and R. Uphus, "iCOM: A new process for final integrated continuous mixing," Deutsche Kautschuktagung DKT2012, Nürnberg, July 5-7, 2012.

2. A. Schröder, L. Gräff, L. Wawrzinski, „Better to hear than to see“, Kautschuk, Gummi Kunststoffe 68 (2015) 10