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Articles
Polymer Compounding Polymer Compounding Accepting new challenges Combining a base plastic resin with colours, modifiers, additive, reinforcements, fillers or other polymers is being carried out in over 3,000 plants at a global level. This is because 55 million metric tonne of plastic materials, constituting roughly one half of the plastics consumed in the world, is not used as base resin. The compounding process is employed to convert raw polymer or base resin to desired plastics that is more effective, uniform and also to be used in varied applications. The product made from such a compound also has improved characteristics such as better performance, lower costs, ease of manufacturing and more attractive appearance. To know more, read on . . . There are over 300 grades of acrylonitrile butadience styrene (ABS) alone and more than 10,000 different grades of plastic materials manufactured using the compounding process. Macro, micro & nano fillers, plasticisers, reinforcements, flame retardants, colourants, carbon black, impact modifiers, lubricants, heat stabilisers, UV stabilisers, antioxidants, organic peroxides blowing agents, anti microbial agents and, antistatic agents are the most common additives that are compounded. Other additives include clarifying agents, cross-linking agents, coupling agents, deodorants, fragrance, nucleating agents, slip agents and vulcanising agents. These are added separately or in combinations to one or several different resin types forming products with unique characteristics suited for myriad applications. Further, these are added in different stages of the process in the form of liquids or solids, either separately or in mixtures to get the required properties in the final compound. Globally, over 30,000 processing units comprising single-screw extruders, internal mixers or dispersive kneaders, reciprocating single-screw extruder (co-kneaders) and twin-screw extruders are currently used for compounding. Over the years, co-rotating twin-screw extruders have played a dominant role in compounding – used by resin suppliers; proprietary and custom compounders or end-users making it the most preferred processing equipment. This dominance is due to the overwhelming advantages of co-rotating twin-crew extruders over other process equipment. These advantages can be stated as:
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