Plasticizer effects on vinyl extrusion efficiency

Abstract

The choice of plasticizer for extrusion of flexible vinyl profiles is usually made for product performance properties. This paper deals with plasticizer influence on the entire extrusion process from dry‐blend preparation to final extruded profile. Undestanding the effect of plasticizer throughout the extrusion line helps the compounder optimize for higher production rates, lower energy input, improved profile quality and better final physical properties. This study focused on the effect of low molecular weight, fast fusing plasticizers in the extrusion processing of general purpose formulations. Butyl benzyl phthalate was used as partial replacement for dialkyl phthalates. A positive influence of this replacement was observed in dry‐blend preparation, in the compound extrusion step, in the finished extrusion step and in final product quality.

Thermal stability of epoxidized soybean oil and its absorption and migration in poly(vinylchloride)

“…Raising the mixer speed to 60 rpm (Fig. 7c) initially resulted in the same torque trends as those observed at lower rpm, but subsequently showed rapid increase in torque and then decline, characteristic of completion of the drying process as reported in Ref 43…”

“…This test is conventionally run at 63 rpm and a set temperature of 88°C. Under these conditions, the torque rises for the first few minutes, but then remains largely flat for some time, before it increases sharply again (this point is referred to as “onset of drying”) to a peak value and then drops to a minimum value (the latter is classified as the “dry blend point,” and said to correspond to the completion of drying) [5,, 16,, 17,, 43]. The results of the present study are shown in Figs.…”

“…At a set temperature of 80°C and 15 or 30 rpm, upon charging the composition to the mixer, the torque decreased initially even as the compound temperature dropped (Fig. 7a and b), corresponding largely to wetting of the PVC grains by the plasticizer [6,, 43]. However, as the ESO was absorbed in the PVC grains, a minimum torque was attained and the trend reversed (i.e., torque started increasing) in spite of the fact that the compound temperature was also rising.…”

“…. Had the composition been removed from the mixer around the dry blend point, it would likely have been close to free‐flowing, as the literature does state that PVC grains are able to move more freely past each other at this point [43]. However, keeping the mixer running well past the dry blend point resulted in a partially fused composition, presumably due to increased flow, as the final temperature attained was 126°C (Fig.…”

Plasticizers

“…Fusion is completed in an intensive mixer such as an extruder or Banbury mixer (27). Substitution for a portion of slow-fusing plasticizer, a small amount of fast-fusing plasticizer can produce shorter processing cycles, less work, higher output, or improved appearance than in unmodified formulations (28)(29)(30)(31). In plastisols a relatively stable fluid dispersion of resin and plasticizer is prepared at room temperature.…”