Ah. Wagner et Dm. Kalyon, PARISON FORMATION AND INFLATION BEHAVIOR OF POLYAMIDE-6 DURING EXTRUSION BLOW MOLDING, Polymer engineering and science, 36(14), 1996, pp. 1897-1906
Parison formation and inflation behavior of three polyamide 6 resins d
uring extrusion blow molding were investigated using cinematography, a
transparent mold, a pinch-off mold and a modified blow pin, which all
owed the pressure inside the parison to be determined during inflation
. The glass fiber filled polyamide exhibited negligible extrudate swel
l and significant drawdown, whereas polyolefin modified polyamide exhi
bited appreciable extrudate swell and relatively small drawdown effect
s. The inflation behavior of the polyolefin modified polyamide was sim
ilar to the behavior of conventional blow molding grade polyolefins, w
hereas the unmodified and glass filled polyamides exhibited different
inflation characteristics. Their inflation behavior at different inter
nal pressures was characterized by decreasing and increasing Hencky st
rain rates with inflation time at high and low internal blow pressures
, respectively. The characterized parison formation and inflation beha
vior of the polyamides emphasize the importance of rigorous blow molda
bility experiments and the difficulties associated with Linking variou
s rheological material functions to the blow moldability of modified p
olyamides.