Functions and Dosage of various PVC Lubricants-3
2022-03-05
It is desirable to know how important lubricants are, but it is critical to know how much to use
Under lubrication or over lubrication affect the processing as well as product quality. Under lubrication will result in frictional heat and degradation of PVC or poor fusion with loss of mechanical properties. Over lubrication is a problem that results in scorching, low output, surging, poor impact strength, poor weld lines and poor surface properties.
When the amount of external lubricants is low, there is an adhesion phenomenon, and the plasticizing time is short. Excessive external lubricants lead to mechanical properties decrease, and there may be precipitation phenomenon.
When the amount of internal lubricants is low, the plasticizing torque is larger, the plasticizing time is longer. If internal lubricants are excessive, the plasticizing time is shorter, the plasticizing torque is smaller, the time of thermal stability is shorter, the inner wall of the product is not smooth.
The PVC Industry has a vast application of waxes. In addition to reducing friction and balancing rheology, lubricants also behave as mechanical stabilizers and pseudo plasticizers. A minor quantity provides a substantial decrease in resistance of chains or chain segments, to movement concerning other polymer chains, or concerning objects in their vicinity. Changes in any material or any piece of equipment in manufacturing result in a need for lubricant adjustment. A lubricant package designed for low heat - high shear machine may fail dramatically in high heat- low shear machine. Processing of rigid PVC is incomplete without waxes.
New lubricants should first be evaluated in the laboratory at different levels, temperatures and shear rates and their operating range are determined. No single laboratory test has demonstrated a complete correlation with the production machinery. But a series of tests help to eliminate materials that do not work.
Understanding and managing PVC lubricants to tune the formulation based on the process is very complex and requires in-depth knowledge. NOVISTA provides technical support and offers solutions to your fullest satisfaction. It is our responsibility that our customers trust and hence work with us closely to find solutions to their challenges. NOVISTA has various combinations of lubricants depending on each application.
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