Internal mixer Banbury

There have been several attempts at models incorporating breakup and coalescence. Two concepts underlie many of these models binary breakup and a flow subdivision into weak and strong flows. These ideas were first used by Manas-Zloczower, Nir, and Tadmor (1982,1984) in modeling the dispersion of carbon black in an elastomer in a Banbury internal mixer. A similar approach was taken by Janssen and Meijer (1995) to model blending of two polymers in an extruder. In this case the extruder was divided into two types of zones, strong and weak. The strong zones correspond to regions... 

All of the composites in this study were prepared in a Banbury internal mixer. After mixing, the curing ingredients and hexamethylenetetramine were added on a 10-inch rubber mill. This milling step causes molecular orientation or grain even in unfilled rubber although the effect is relatively small. 

Banbury internal mixer [Farrrel Corp., Ansonia, CT)... 

The mainstays of the rubber industry for over 70 years has been the two-roll (open) mill and the Banbury (internal) mixer. Roll mills were first used for rubber mixing over 120 years ago. The plastics and adhesives industries later adopted these tools. 

Mechanical mixing of polymers carried out on either an open mill or in a Banbury internal mixer has advantages in efficiency, productivity, and lower cost. However, natural rubber in many instances must first undergo an initial breakdown. 

The first step of manufacturing a membrane is to prepare a suitable rubber compound either in a Banbury internal mixer or in an open two roll mixing mill by adding different compounding ingredients in the proper sequence during the mixing operation to get a well dispersed compound. 

Work by Lee et al. [14] provides a transition from discussions centered on polyethylene-montmorillonite nanocomposites to discussions focused on polypropylene-montmorillonite nanocomposites. An extruder was not employed to prepare the polymer nanocomposites. A Haake Banbury internal mixer prepared the polymer-montmorillonite concentrates (180°C, 10 min, and 50 r/min) and the final polymer composites. The montmorillonite in this study was Kunipia-F from Kunimine, Japan. Octadecylamine served as the organic modification for the montmorillonite. The polymer concentrates were prepared with polypropylene grafted with maleic anhydride (PP-g-MA Umex 1010 from Sanyo) and PE-g-MA (Umex 2000 from Sanyo). The PP-g-MA-organomont-morillonite concentrates demonstrated superior dispersion of the montmorillonite in relation to the PE-g-MA concentrates. Hence, most of the effort in preparing and characterization of the final polyethylene composites centered on the PP-g-MA-montmorillonite concentrates. The concentrations of montmorillonite in the concentrates were 12.5, 30,... 

Most additives that affect mix procedirres are reactive chemicals. To run a chemical reaction successfully in a Banbury internal mixer or other equipment, three variables need to be controlled time, temperature and stoichiometry (the ratio of the reactants). The effect of these variables on the chemical peptising of NR, SBR, polychloroprene (CR) and Thiokol polysulphide are discussed. Other topics include additives to increase viscosity, when to add zinc oxide, filler treatments and bin storage problems. 10 refs. 

Another group in Malaysia [10] have looked into the viability of using reclaimed rubber from rejected NBR gloves in blends of PP for the production of thermoplastic vulcanisate(s) (TPV). The reclaimed NBR was evaluated as a partial replacement for virgin NBR in the blends in the range 40-70 phr. The TPV were prepared from the starting materials using a Banbury internal mixer, with... 

SBR mbber compounds are prepared in two stages the nonproductive and the productive phases. In the nonproductive phase the compound ingredients are mixed, usually in internal mixers (Banbury). The mixing time is usually short and the compound temperature is in the 160—195°C range. 

Elastomer-plastic blends without vulcanization were prepared either in a two roll mill or Banbury mixer. Depending on the nature of plastic and rubber the mixing temperature was changed. Usually the plastic was fed into the two roll mill or an internal mixer after preheating the mixer to a temperature above the melting temperature of the plastic phase. The plastic phase was then added and the required melt viscosity was attained by applying a mechanical shear. The rubber phase was then added and the mixture was then melt mixed for an additional 1 to 3 min when other rubber additives, such as filler, activator, and lubricants or softeners, were added. Mixing was then carried out with controlled shear rate... 

Figure 35.4 shows the concept of the internal mixer proposed by Banbury. It can be seen easily that the basic concept of the internal mixer did not change since almost 90 years. Obviously the advantage of the easily feeding is preferred above the rather poor between batch consistency. 

FIGURE 35.4 The concept of the internal mixer as suggested by Banbury (1917). 

The type of internal mixer designed by F.H. Banbury the name Banbury is often erroneously applied to any type of internal mixer. Barium Sulphate... 

Processing variables can affect to a very great extent the results obtained on the rubber product or test piece and, in fact, a great number of physical tests are carried out in order to detect the result of these variables, for example state of cure and dispersion. In a great many cases, tests are made on the factory prepared mix or the final product as it is received but, where the experiment involves the laboratory preparation of compounds and their moulding, it is sensible to have standard procedures to help reduce as far a possible sources of variability. Such procedures are provided by ISO 2393 which covers both mills and internal mixers of the Banbury or Intermix type, and also procedures for compression moulding. 

Internal mixers, such as the Banbury mixer (Figure 11.5), contain two connecting chambers, in which blades rotate in opposite directions with a narrow clearance to the walls, resulting in local high rates of shear. The walls can be cooled or heated. After mixing, the pieces are removed from the chambers, milled into a sheet and cut into ribbons for storage or further processing. 

From the mathematical point of view the complexity is reduced because the system of equations which has to be solved is a function defined on the two-dimensional manifold of the control volumes boundary and leads to a dimension reduction. Practically the discretisation of the boundary usually is more simple than the meshing of complex three dimensional volumes. Especially this pertains to the transient flow channel geometry in co-rotating twin screw extruders. The surface meshes for the screws can independently be rotated inside the screw and barrel mesh analogous to the batchwise working internal mixer (Banbury Mixer) shown in the bottom part of Fig. 5.26. 

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