On-Line measurement and mathematical modeling of fiber properties during the melt spinning and melt blowing processes /

Abstract

The on-line measurements during the melt spinning process were used to quantitatively evaluate the effect of molecular orientation (caused due to threadline stress) on the crystallization rate of polymers.

An on-line experimental study of the melt spinning and melt blowing polymer fiber forming processes was performed. During melt spinning, the fiber properties measured included fiber diameter, temperature, velocity, birefringence, density, and crystallinity. In order to determine the fiber density, a novel technique using the continuity equation, in conjunction with the measured diameter and polymer mass flowrate, was developed. Heretofore, the fiber density has never been measured on-line during fiber forming processes. The fiber crystallinity was then determined from the measured density using a mixing rule. The measurements made during the melt blowing process included fiber diameter and temperature. The on-line measurements during melt blowing were compared with the Uyttendaele-Shambaugh mathematical model for melt blowing.

Also developed was a mathematical model for the melt blowing process. This model is a 3-dimensional, logical extension of the 2-dimensional Rao-Shambaugh model for melt blowing. The utility of this model lies in the simulation of melt blowing from the slot melt blowing dies (e.g., an Exxon die). The useful information predicted from the model includes fiber diameter, temperature, threadline stress, and fiber motion.