Microporous membranes having increased pore densities and proces

Details Microporous membranes having increased pore densities and proces Microporous membranes having increased pore densities and proces

1989-11-09

1991-05-07

Spear, Frank

Liquid purification or separation

Filter

Material

21050036, 264156, B01J 7126

Patent

active

050134396

ABSTRACT:
Disclosed are a process for forming an open-celled microporous membrane (e.g., in film or fiber form) and a novel microporous membrane formed thereby. The process generally includes sequential cold and hot stretching operations, whereby the cold stretching operation is preferably accomplished in a plurality of discrete cold stretching steps. In this regard, the total cold stretch extension is of greater than about 30 percent, and advantageously greater than about 40 percent based upon the initial unstretched length of the nonporous precursor, with this total cold stretch ratio being distributed among a plurality of discrete cold stretching steps. The novel membranes of this invention are characterized by decreased pore size and increased pore densities. For example, the membranes of this invention will have an average pore radius as determined by mercury porosimetry of less than about 0.040 micron. The membranes of this invention, moreover, exhibit a distinctive "bluish" color hue (i.e., a Macbeth Coloreye.TM. b* value of less than about -10 as determined by placing a single ply sample of the membrane against a black background).

REFERENCES:
patent: 3426754 (1969-02-01), Bierenbaum
patent: 3679538 (1972-07-01), Druin et al.
patent: 3801404 (1974-04-01), Druin et al.
patent: 3801692 (1974-04-01), Zimmerman
patent: 3839240 (1974-10-01), Zimmerman
patent: 3839924 (1974-10-01), Zimmerman
patent: 3843761 (1974-10-01), Bierenbaum et al.
patent: 3880966 (1975-04-01), Zimmerman et al.
patent: 4138459 (1979-02-01), Brazinsky et al.
patent: 4255376 (1981-03-01), Soehngen
patent: 4257997 (1981-03-01), Soehngen et al.
patent: 4405688 (1983-09-01), Lowery et al.
patent: 4541981 (1985-09-01), Lowery et al.
patent: 4664681 (1987-05-01), Anazawa et al.
patent: 4696748 (1987-09-01), Nitadori et al.
S. Brunauer et al., Journal of American Chemical Society, vol. 60, p. 309 (1938).
F. M. Nelson et al. Analytical Chemistry, vol. 30, p. 1387 (1958).
"Application of Mercury Penetration to Materials Analysis", Clyde Orr, Jr., Powder Technology, 3, pp. 117-123 (1969/70).

Affiliated with

Also associated with

Rating

Microporous membranes having increased pore densities and proces does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Microporous membranes having increased pore densities and proces, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Microporous membranes having increased pore densities and proces will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-937881