A Mechanics of Materials Model for the Creping Process

The manufacture of low density paper such as tissue and towel utilizes the creping process that consists of adhesively bonding the paper in wet state onto the surface of a smooth drying cylinder and scraping it off with a blade once dried. In this paper, a mechanics of materials description of the creping process is presented. Based upon previous experimental observations, the mechanism of this creping process is proposed as a periodic debonding with a strength-of-materials failure criterion applied and buckling sequence of an elastic thin film. Numerical calculations show results consistent with experimental data and known industrial observations. Crepe wavelength versus creping angle data from experiments can be satisfactorily reproduced by a reasonable set of values for input parameters to the model. Parametric study shows the adhesive shear strength and the sheet stiffness most significantly affect the crepe wavelength and the creping force. The model provides guidance in understanding and optimizing the creping process to produce high quality products.