International Paper Company

Ralph E Brandon

Michael E Ring

Charles J Davis

Roy S Swenson

Raymond Redner, Iii

James B Morris

An improved process for forming a non-woven fabric by wet-laying, on paper making equipment, staple length, synthetic fibers having a length to diameter ratio of about 400 to 3000, and an improved, non-woven fabric produced by the process. The process involves forming a stable, viscous, uniform, air-fiber-water dispersion by: adding the fibers to a high-shear agitated mixture of water and a dispersant to separate the fibers and to completely and uniformly distribute the individual fibers throughout the resulting, high-shear agitated, air, water and fiber mixture; and then, slowly adding a thixotropic thickener to the high-shear agitated mixture to form the viscous, air-fiber-water dispersion, having a nascent viscosity of about 10 to 125 cps., when measured at a shear rate of 30.5 sec..sup.-1, and in which the individual fibers are restrained from becoming entangled and from forming knits, bundles, and strings.

Wet-laid, non-woven fabrics

Viscous dispersion for forming wet-laid, non-woven fabrics

A process and device useful therein for hydraulically entangling the fibers in a fiber batt to form a fiber-entangled base sheet for a non-woven fabric, and a uniformly and lightly fiber-entangled, base sheet formed by the process. The process includes applying at least one liquid curtain against the fiber batt while it is supported on a moving, apertured backing screen. The liquid curtain is uniform in width throughout its length and substantially non-diverging as it is delivered from a source of liquid under a pressure sufficient to effect entanglement of the fibers in the batt. Preferably, the pressure is at least about 200 p.s.i.g., and the maximum divergence of the curtain is about 4 degrees. The device for applying the liquid curtain includes first and second members and means for securing the members together to form a chamber therebetween in which the liquid is contained and to form a slot in communication from the chamber to the exterior of the device. The slot has a substantially uniform width along its length and preferably also a uniform depth. The securing means are adjustable, so that the width of the slot can be varied, but, once the members are secured together, the width of the slot remains constant as the curtain is delivered from the chamber, through the slot, and against the fiber batt. The uniformly and lightly fiber-entangled, base sheet is non-apertured and non-streaked and has an entanglement frequency of less than about 20, an entanglement completeness of less than about 0.5 and an internal bond value of less than about 0.1.

Non-woven fabric lightly fiber-entangled

In an apparatus for forming a non-woven, fibrous web, a device for making a uniform density dispersion of the fibers in an aqueous fiber slurry and depositing the dispersion onto a web former, while maintaining its integrity. The device includes a generally laterally divergent channel, in which the greatest depth of the flowing stream of fiber slurry is at its fiber slurry entry end, having rolls for uniformly dispersing the fibers, rolls for uniformly spreading the dispersion laterally throughout the channel, and means in cooperation with the rolls for moving the dispersion to an exit end of the channel adjacent the web former. Preferably, the device is equipped with air doctors directed at the rolls for insuring the separation of the dispersion from each roll as it is moved to another roll.

Entangled non-woven web-forming apparatus

A process and device useful therein for hydraulically entangling the fibers in a fiber batt to form a non-woven fabric. The process includes applying at least one liquid curtain against the fiber batt while it is supported on a moving, apertured backing screen. The liquid curtain is uniform in width throughout its length and substantially non-diverging as it is delivered from a source of liquid under a pressure sufficient to effect entanglement of the fibers in the batt. Preferably, the pressure is at least about 200 p.s.i.g. and the maximum divergence of the curtain is about 4 degrees. The device for applying the liquid curtain includes first and second members and means for securing the members together to form a chamber therebetween in which the liquid is contained and to form a slot in communication from the chamber to the exterior of the device. The slot has a substantially uniform width along its length and preferably also a uniform depth. The securing means are adjustable so that the width of the slot can be varied; however, once the members are secured together the width of the slot remains constant as the curtain is delivered from the chamber, through the slot, and against the fiber batt.

Growing community of inventors

Monroe, NY, United States of America

Ralph E Brandon