Title:
POROUS TUBE OF POLYTETRAFLUOROETHYLENE AND ITS MANUFACTURE
Document Type and Number:
Japanese Patent JP3811253
Kind Code:
B2
Abstract:
PROBLEM TO BE SOLVED: To form layers of different pore structure by first, applying a dispersion of polytetrafluoroethylene powder to a porous tube, and removing by evaporation the coat through heating it, and further, integrating particles of polytetrafluoroethylene to each other by heating them above a melt point to stretch in a uniaxial direction.
SOLUTION: A paste-like mixture comprising fine powder of polytetrafluoroethylene(PTFE) and an organic solvent as an extrusion assistant is performed. After that, the performing is transferred to the cylinder of an extruder to be extruded in the form of a tube. This extruded product is stretched in a longitudinal or a diametrical direction to make it porous. Further, a PTFE dispersion is coated to the stretched product. In additon, the coat is dried by an air and then is placed in a dryer at about 100°C to remove a solvent from the dispersion by evaporation. Next, this solvent-free coat is heated above a melt point, resulting in a change in the pore diameter and porosity of the coat ensuring from a change in the integrity of particles. Finally, the coat is stretched which in turn, causes the coat to be porous and consequently, the porosity to further augment.
Inventors:
Hiroyuki Nishii
Toshihiko Ariyoshi
Toshihiko Ariyoshi
Application Number:
JP13558197A
Publication Date:
August 16, 2006
Filing Date:
May 26, 1997
Export Citation:
Assignee:
NITTO DENKO CORPORATION
International Classes:
B01D39/16; B32B1/08; B29C55/22; B32B5/18; B32B27/30; C08J9/00; B29K27/12; B29L9/00; B29L23/00; (IPC1-7): B32B1/08; B01D39/16; B29C55/22; B32B5/18; B32B27/30; C08J9/00; //B29K27:12; B29L9:00; B29L23:00
Domestic Patent References:
| JP4351645A | ||||
| JP1078823A |
Attorney, Agent or Firm:
Hiroyuki Ikeuchi
Kimihiro Sato
Kimihiro Sato