Colors of dope and yamn of spun‐dyed cellulose acetate

Abstract

Novaccta S p.A L'iale Picmonlc 66 2001 3 h1ngcnt;i. Italy Demetrio Pitea Institutc 01' Physical Chcmistry University of Milnn Via C. (iolgi 1' 9 20133 Milano. It;ily A merhod of color control of bulk-d.wd cellulose acefate is described, based on the tran,smiftani,~i spectrum of the dope. (.onfro1 can be ej'ected only if the spectruwr is recordedfi-om thick samples which ampl$y the absorption from stnall amounts of impurities that later cause unacceptable color dij"erences on the yarn. The calculation of the reflec.tunce spectrum, and hence the color, ofthe yarn f r o m the transmitfanre spectrum of f h e dope by Kubelka-Munk theory i s not satisfactory due to Jhint f u rhidity (?f'the "bright" dope. The rtlflectance spectrum of the yarn can be calculated from a series expunsion ofthe experimrntal Lambert law ubsorprion cocdjirient with very safisf&tory results. A fully computer-nmiuged colorcontrol method i s employed .successfully in industrial practice.