Ultrasonically-assisted process for making differential density cellulosic structure containing fluid-latent indigenous polymers.

摘要

A process and an apparatus for making a differential density cellulosic web comprising a first plurality of high-density micro-regions and a second plurality of low-density micro-regions are disclosed. The process comprises the steps of providing a fibrous web containing fluid-latent indigenous polymers and water; depositing the web on a fluid-permeable molding fabric; applying ultrasonic energy to the web, thereby contributing to softening of the fluid-latent indigenous polymers in at least selected portions of the web; impressing the molding fabric into the web, thereby densifying the selected portions of the web and causing the fluid-latent indigenous polymers to flow and interconnect the fibers which are mutually juxtaposed in the selected portions; and immobilizing the fluid-latent indigenous polymers, thereby creating bonds thereof between the fibers which are interconnected in the selected portions. An apparatus comprises an ultrasonic means for applying ultrasonic energy to the web associated with the molding fabric, and a pressing means for impressing the molding fabric into the web.