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:
May. 23, 1989
Filed:
Nov. 20, 1987
Applicant:
Inventors:
Emmanuel Balanzat, Caen, FR;
Claude Bieth, Troarn, FR;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
B44C / ; B32B / ;
U.S. Cl.
CPC ...
428131 ; 156628 ; 156643 ; 156644 ; 156654 ; 156663 ; 156668 ; 2504921 ; 4283155 ;
Abstract
Process for the production of asymmetrical microporous membranes by double irradiation. A membrane (5) is exposed to two irradiations, whereof one has an inadequate energy level to pass through the same, whereas the other passes through membrane (5). The irradiations produce molecular defects, which are attacked or etched in preferred manner by certain chemical agents. Thus, two networks of pores are obtained, one network being of large diameter and of a non-issuing nature (26), the other being smaller (27, 28, 29) and which issue on to the two surfaces (31, 32) of membrane (5). Application to filtration and sterilization.