Kneader Process

This continuous votator process was first used for margarine production by Girdler USA in 1938, introduced in the UK during the 2nd World War and in the rest of Europe in the 1950s. In some factories, the semi-continuous cooling drum/hopper/vacuum kneader process is still used, but almost exclusively for special-purpose margarines. 

The second process to finish phthalocyanine, which is more important for P-copper phthalocyanine, involves grinding the dry or aqueous form in a ball mill or a kneader (64). Agents such as sodium chloride, which have to be removed by boiling with water after the grinding, are used. Solvents like aromatic hydrocarbons, xylene, nitrobenzene or chlorobenzene, alcohols, ketones, or esters can be used (1). In the absence of a solvent, the cmde P-phthalocyanine is converted to the a-form (57,65) and has to be treated with a solvent to regain the P-modification. The aggregate stmcture also has an impact on the dispersion behavior of a- and P-copper phthalocyanine pigments (66). 

Batch Saponification. Batch saponification, the oldest PVA manufacturing method (252), is mainly used in the 1990s for the production of specialty products. The process uses a kneader in which the hydrolysis, washing, and drying operations are performed. This is the simplest method of saponification, but the production rates are low, and producing the product quaUty needed by many end uses is difficult. 

Bulk Material Processing Leaders Feeders Blenders Dryers Kneaders... 

Most plastics e.g. polyolefins and polystyrenes and their derivatives such as ABS (acrylonitrile-butadiene-styrene) and SAN (styrene-acrylonitrile) are supplied by the manufacturers in ready-to-use form with most of the above-mentioned stabilizers or simply need to be additionally stabilized with other additives, e.g. antistatic agents and HALS stabilizers, as required. On the other hand, in the case of other materials (e.g. PVC) it is the end user who adds the additives, pigments or preparations. This is normally done on fluid or high-speed mixers, although in the past gravity mixers or tumble mixers were also used. The mixture is then homogenized on mixing rolls, kneaders, planetary extruders or twin-screw kneaders and further processed. 

Baking is currently performed by continuous operation. Modern variations involve using heated crushing or milling equipment, such as kneader dispersers or oscillating mills at approximately 200°C [9]. This technique significantly improves the reaction control over a batch process. If baking is performed by continuous process, phthalonitrile only remains within the reaction vessel for a very short period of time (between 3 and 20 minutes). It is important to remember that the temperature may not exceed 250°C. The product which evolves from this process is usually purified by acid treatment. 

While the Dove composition described in Table 9.4-2 was processable at reasonable line speeds on a conventional soap processing line (roll mills, extruders, stampers), some equipment modifications were necessary. For example, whereas soap is normally mixed in large agitated tanks, the Dove mixture had a much greater viscosity and therefore required use of a steam-jacketed kneader mixer such as those used to make bread dough, pastes or mastics. 

In the case of the wet granulation process in a mixer/kneader, the granulation process can be easily monitored by the determination of the power consumption (6-9) (Fig. 1). 

These products, are processed by dissolving them in a mixture of alcohol and ether, kneading into a dough, filtering in a hydraulic press to remove mechanical impurities and adding to the fresh powder mass in the kneaders. 

Some factories (e.g. in Austria) which before and during World War I encountered many difficulties in manufacturing ballistite by the method described above modified the process after the mass had been rolled to dry it, it was transferred to kneaders and a small amount (2-8%) of acetone was added. This greatly facilitated the next, final rolling which could be then conducted at a lower temperature (70°C). 

Further, the use of aqueous additive systems eliminates dust and compaction problems associated with the handling of powder form additives. Finally, the use of aqueous additive systems provides flexibility for mixing the additive with the resin. The additive can be mixed and dried with the resin still in moist, wet-cake form. It can be blended with other formulation ingredients, or pumped into an extruder or kneader during the compounding step. This flexibility can, in turn, provide still lower-cost processes and improved uniformity of mixing. 

The new concept for processing of bimodal polyolefins was first presented in 2004 at the Kunststoffmesse in Dtisseldorf. The system, known as the ZSK-NT, combines two corotating, twin-screw kneaders in a cascade arrangement. Figure 15.1 shows the setup of the two ZSKs operating as ZSK-NT. ... 

The incorporation of particulate fillers into the liquid epoxy formulation can be achieved with any of the processes mentioned above by the use of roll mills or screw-type kneaders. If the formulation is solid, fillers may be blended into the product by the use of a pebble mill or the like. After blending, they may be rolled under pressure and then ground if desired. 

Although most solid propellants are manufactured in a vertical mixer batch process, a continuous mixing process has been used successfully in the production of the first stage A-3 Polaris propellant and in the NASA 260 inch demonstration motor program. The use of a continuous mixing process, in which propellant chemicals are metered into a helical kneader, offers considerable benefit in terms of safety and cost for large-volume propellant production. 

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