A new fiber-forming method, and related apparatus, and webs prepared by
the new method and apparatus are taught. In the new method a) a stream of
filaments is extruded from a die of known width and thickness; b) the
stream of extruded filaments is directed through a processing chamber
that is defined by two narrowly separated walls that are parallel to one
another, parallel to said width of the die, and parallel to the
longitudinal axis of the stream of extruded filaments; c) the stream of
filaments passed through the processing chamber is intercepted on a
collector where the filaments are collected as a nonwoven fibrous web;
and d) a spacing between the walls of the processing chamber is selected
that causes the stream of extruded filaments to spread before it reaches
the collector and be collected as a web significantly wider in width than
the die. Generally the increase in width is sufficient to be economically
significant, e.g., to reduce costs of web manufacture. Such economic
benefit can occur in widths that are 50, 100 or 200 or more millimeters
greater in width than the width of the die. Preferably, the collected web
has a width at least 50 percent greater than said width of the die. The
processing chamber is preferably open to the ambient environment at its
longitudinal sides to allow pressure within the processing chamber to
push the stream of filaments outwardly toward the longitudinal sides of
the chamber.