A Declaration of Conformity Covering Only the Base Polymer
Base polymer declarations certify monomer purity at the reactor gate but omit all converter additives, breakdown products, and finished article migration limits.
Masterbatch Compounding
Meaning
An industrial process mixes high concentrations of pigments, additives, or fillers into a carrier resin to produce a concentrated pellet that can be easily blended with virgin polymer during moulding. This Masterbatch Compounding ensures that small quantities of active ingredients are evenly distributed throughout the final plastic part. It prevents the clumping of pigments and ensures consistent color and performance.
Compounding Process
The process is typically carried out in a twin-screw extruder where high shear forces melt the carrier resin and disperse the additives. The melt is extruded through a die, cooled in a water bath, and cut into pellets. The carrier resin must be compatible with the base polymer of the final part to ensure proper blending and to avoid mechanical defects.
Processing Variable
Controlling the temperature profile, screw speed, and feed rate is necessary to prevent the thermal degradation of the additives. If the shear is too low, the pigments will not disperse fully, leading to streaks or specs in the moulded part. The compounder must optimize these parameters to produce a uniform concentrate.
Moulding Efficiency
Moulders use the compounded masterbatch to simplify material handling and to reduce the need for raw powder additives on the factory floor.