Fiber-forming process

Abstract

A new fiber-forming method, and related apparatus, are taught in which extruded filaments of fiber-forming material are directed through a processing chamber that is defined by two parallel walls, at least one of which is instantaneously movable toward and away from the other wall; preferably both walls are instantaneously movable toward and away from one another. Movement means provide instantaneous movement to the at least one movable wall. In one embodiment, the movement means comprises biasing means for resiliently biasing the wall toward the other wall. Movement of the wall toward and away from the other wall is sufficiently easy and rapid that the wall will move away from the other wall in response to increases in pressure within the chamber but will be quickly returned to its original position by the biasing means upon resumption of the original pressure within the chamber. In another embodiment the movement means comprises oscillating means for oscillating the wall at a rapid rate. The invention also provides new nonwoven webs, which comprise a collected mass of fibers that includes fibers randomly interrupted by isolated fiber segments that comprise oriented polymer chains but differ in morphology from the main portion of the fiber.

Description

Background technique [0001] In many fiber forming processes, filamentary material extruded from a die is directed through a processing chamber where, for example, the fiber material is drawn, oriented and / or reduced in diameter. Such treatment or attenuation chambers are commonly used in spunbond processes (see US Patent Nos. 3,502,763; 3,692,618; 4,064,605; 4,217,387; 4,812,112; 4,820,459; 5,270,107; 5,292,239; 5,571,537; 5,648,041 and 5,688,468). But it can also be used in other processes such as melt blowing process (see US Patent Nos.4622259 and 4988560), melt spinning of filaments and filament yarns (see US Patent No.4202855), and from silk film fiber material in flash spinning. [0002] The use of a treatment chamber imposes limitations on the overall fiber forming process - these limitations attempt to ensure that the fibers will travel efficiently through the chamber without, for example, clogging the chamber. These limitations include limitations on the speed of the...

AI Technical Summary

Problems solved by technology

[0005] All of these methods still continue to impose significant constraints on the fiber forming process due to the utilization of process chambers

Images