PVC compounding is a process of mixing homogenously the different ingredients of compound formulation, to achieve various properties as required by the end application. The basic ingredient, Polyvinyl Chloride resin is compounded with a number of additives such as stabilizers, lubricants, property modifiers, pigments, plasticizers, filers etc. These elements of compound, in definite proportions, are mechanically mixed in a high speed mixer. The output is normally called “Premix” or Dry blend “which is in the form of free flowing powder. In certain applications the dry blend can be used directly in the processing equipment. In many other applications the dry blend is necessarily melt compounded and pelletized. PVC compounded pellets are widely used to various applications like shoes, cable insulation and sheathing, fittings, bottles, medical bags and tubing etc.
For producing compounded PVC pellets, many different types of process equipment are available. Kabra Extrusiontechnik offers the ideal range of counter rotating twin screw extruders which have many advantages stated below.
The essential units in the line are: Extruder, DFC system, Pneumatic conveying system and Pellet coolers.
Twin Screw Extruders :
Die Face Cutter: The compounded hot melt is required to be cut at faster speed in form of circular, even shaped granules. Die face cutter having variable speed motor with VF drive perform dry cutting action. The main advantages are:
Pneumatic Conveying System and Pellet Cooler: The pellets cut by the DFC drop down to be transported through a tunnel having air flow through blowers and suction. Diverter valves are provided. At the end of conveying system the pellets are semi cooled and for further lowering of heat to the ambient temperatures they are cooled in Pellet Cooler. In order to prevent sticking, deformation and possible thermal degradation, it is important to extract heat from the pellets rapidly.It consists of a main silo in which the pellets are unloaded, a small silo through which the pellets are passed on to the cooling screen having perforations and vibrator. Cooling of pellets by the medium of air offers many advantages:
Kabra has installed more than 1600 of such PVC palletizing plants successfully. Besides India many compounders in Saudi Arabia, South Africa, Ethiopia, U.A.E, Bangladesh, and Kuwait have greatly benefited from KET’s Twin Screw PVC Pelletizing Lines
|Model||Indicative SPVC Kg/Hr (Output Filled)||Indicative SPVC Kg/Hr (Output Unfilled)|
|2 – 25 - 25V||100 - 170||85 - 130|
|2 – 65 – 22V||150 – 250||140 - 190|
|2 – 68 – 28 V||200 – 350||190 - 250|
|2 – 92 – 28 V||450 - 700||450 - 550|