New model of flow in a Farrel Continuous Mixer

International Polymer Processing

2010

During the last quarter of the 20th century, there was a transition from batch to continuous mixing in the polymer and food industries. We present and summarize experimental studies of flows in both internal and continuous mixers. Simulation of flow in these machines is also described. It is argued that the primary reason for this transition was that continuous mixers produce more uniform and better quality mixes, and that this is inherent in their different fluid mechanics. Batch mixers are always starved and largely unpressurized. Their complex fluid mechanics produce non-uniform mixing in the various portions of the compound material. Continuous mixers set up a steady state hydrodynamic flow field generally consisting of alternating regions of pressurized fully filled flow and starved flow. All of the compounds must pass through these regions to reach the die exit and thus possess uniform mixing histories. This uniform deformation history which includes pressurized mixing regions produces superior uniform products.

Section: Flow Simulations In Batch and Continuous Mixerssupporting

confidence: 72%

Perspectives on the Transition from Batch to Continuous Mixing Technologies in the Compounding Industry

International Polymer Processing

2010

“…The continuous mixer used was a product of Kobelco Stewart Bolling, Model NEX‐T 60. This type of continuous mixer has been discussed by various authors 14–18. The machine consisted of two sections: a top mixing chamber and bottom single screw extruder.…”

Section: Methodsmentioning

confidence: 99%

“…Residence time distributions for the Kobelco continuous mixer were measured using aluminum flakes. This indicates the length of time during which the material stays in the continuous mixer 16, 17…”

Section: Methodsmentioning

confidence: 99%

Development of dispersion in rubber‐particle compounds in internal and continuous mixers

Liú

J of Applied Polymer Sci

2006

Self Cite

Experiments of mixing silica, carbon black, and CaCO 3 into various elastomers (EPDM, NBR, and SBR) were carried out in this paper. We have investigated the breakup of filler agglomerates in the mixing process and compared the mixing results between the internal mixer and the NEX-T continuous mixer. We have evaluated the impact of the elastomer type, filler type, filler loading, and mixing time on the breakup of filler agglomerates. When the filler agglomerates break up, the agglomerate size was reduced to a steady state size. The steady state size primarily depends on the type and primary particle size of the filler. A model was developed for the rate of agglomerate breakup.

“…Various calcula tions have been made to analyze the flow in their mixing, including fill factors and pressure profiles [118,119]. …”

Section: Tangential Counter-rotating Twin-screw Extrusionmentioning

confidence: 99%

Polymer Blend Compounding and Processing

Encyclopedia of Polymer Blends

2011

Self Cite

Humankind has been mixing together different materials since the dawn of written history to produce products with improved engineering properties. The term Bronze Age (which began around 3000 BC) indicated the blending of tin into copper to improve its mechanical performance. Concrete was also introduced by the ancients with similar purposes in mind.The polymer industry as we know it dates only from the first part of the nineteenth century, where the major industrial polymers aside from wood were natural rubber ( -1,4-polyisoprene) from Brazil, gutta-percha ( -1,4-polyisoprene) from Singapore and Malaya from the 1840s, and natural fibers, including cellulose (cotton, linen) and protein (wool) fibers and leather. Many of the earliest patents involved coating fabrics and leather with natural rubber [1-6]. There was a gradual realization in this period of the usefulness, in terms of improving the properties or rubber, of introducing solid particulates [7-10] or chemicals such as sulfur and its compounds [10-13], which caused vulcanization/crosslinking. It was only with the commercial appearance of gutta-percha in about 1845 [14-17] that there were investigations of polymer blends (gutta-percha with natural rubber). These were reported in patents of C. Hancock [17,18], A. Parkes [13] and W. Brockedon and T. Hancock [19] in 1846. All of these inventors knew each other, Two were brothers (C. Hancock and T. Hancock) and two others (Brockedon and Parkes) were at the time business colleagues of the above T. Hancock. The patents cited above generally cite one or more of the others. This all took place in or near London, England.The mixing processes are usually not critically discussed in these early patents. Brockedon and Hancock [19] indicate they used the single rotor masticating machine discussed in T. Hancocks earlier patents [6,7]. One can conclude by reading their patents that C. Hancock and Parkes used the same or similar machines. Parkes [13] mentioned using rollers, perhaps similar to the machine of Chaffees patent [5]. In addition, significant amounts of solvents derived from coal tar were used. First Edition. Edited by Avraam I. Isayev.