The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Apr. 08, 1986
Filed:
Jul. 31, 1984
Raymond E Kelchner, Jr, Los Angeles, CA (US);
Hughes Aircraft Company, El Segundo, CA (US);
Abstract
A polymeric fibrous sheet is provided in the form of a composite of an open matrix of coarse fibers extending throughout the sheet and integrated with co-crystallized, fine fibers spanning the open spaces within the matrix. This non-woven sheet is formed by applying a thin film of polymer solution to the top surface of a substrate undergoing agitation. The substrate can be continuous, such as a belt, agitated by applying oscillatory motion from an acoustic or pneumatic driver to the shafts carrying the cylindrical rollers for the belt. The agitation is at a level sufficient to develop a reciprocating flow field with a velocity gradient sufficient to uncoil and orient the polymer chains in solution and induce the growth of fibers. As the agitated solution cools, a sheet is formed as linear polymer chains crystallize. Residual solvent is removed and the sheet is then dried in the dryer. Sheets with higher fiber content and strength are produced by using substrates containing grooves, especially substrates containing a second set of grooves normal to the first set of grooves, formed by a pattern of raised protrusions. The sheet produced using the patterned substrate contains a network of coarse fibers which roughly replicate the pattern of the grooves.