Cellulose Acetate Fiber Production

Continuous measurement and control of the dope concentration for high quality cellulose acetate fiber production

There are two types of cellulose-based fibers: regenerated or pure cellulose (such as the fibers from the cupro-ammonium process) and modified cellulose (such as the cellulose acetates and rayon).

Cellulose acetate is a forming substance for acetate fiber.  Acetate is obtained by dissolving wood pulp into purified cellulose. Cellulose acetate dope is produced by reacting the purified cellulose with acetic acid and acetic anhydride, using sulfuric acid as a catalyst. Next, the mixture goes through the process of hydrolysis where sulfate is removed and the product receives the desired properties. Finally, acid-resin flakes are dissolved in acetone and the solution is filtered.

At the next stage the spinning dope is extruded, solvent is recovered and purified for reuse. The filaments are stretched wound onto bobbins to obtain the final product. 

In-line Vaisala Polaris^TM process refractometer is used to monitor the concentration of the dope solution prior to the spinning of the fibers. Accurate concentration measurements of the dope impacts the quality of the final product. 

Another refractometer can be installed in the solvent recovery area to maximize acetone recovery and reduce operation costs.

Learn more about the cellulosic fibers production process from the application note.

Download the application note in PDF by filling the form.

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