METHODS FOR REDUCING THE TENDENCY OF LYOCELL FIBERS TO FIBRILLATE

A study has been made of the influence of various process parameters o n the fibrillation characteristics of Lyocell fibers, which are spun f rom a solution of cellulose in N-methylmorpholine-N-oxide (NMMO). The parameters were air gap length, temperature, and humidity; line speed; draw ratio; polymer solution cellulose and water contents; and coagul ation bath concentration and temperature. Fibrillation was induced in the fibers by an ultrasonic treatment and compared by defining a fibri llation index from optical micrographs. By selecting combinations of t he parameters described above, fibrillation can either be increased or decreased without significantly affecting the tensile properties of t he fibers. A method for spinning nonfibrillable filaments on a laborat ory scale is presented. (C) 1996 John Wiley & Sons, Inc.