Melt blowing of tubular filters
AssigneeExxon Chemical Patents Inc.
InventorsMartin A. Allen, John T. Fetcko
Life of this patent
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Abstract
An apparatus and method for producing a meltblown continuous and seamless nonwoven tube is described. The apparatus comprises a meltblowing die for extruding two groups of polymer thermoplastic filaments onto a rotating mandrel to form a multilayer layer tube thereon. The tube is withdrawn from the mandrel by a rotating screw. The present apparatus is capable of producing nonwoven tubes having variable fiber diameters and/or composition in the radial direction, making them ideally suited for filtration purposes.
Claims20
Apparatus for manufacturing a nonwoven seamless continuous tube which comprises:
- (a) a meltblowing die having a first and second groups of orifices;
- (b) a rotating mandrel positioned in alignment with the orifice groups;
- (c) a first pump for delivering and extruding a polymer melt through the first group of orifices to form a first seamless filament layer on the mandrel;
- (d) means for moving the first filament layer under the second group of orifices;
- (e) a second pump for delivering a polymer melt through the second group of orifices to form a second seamless layer of filaments on the first layer, thereby forming a two-layered tube;
- and
- (f) means for withdrawing the tube from the mandrel.
Apparatus for manufacturing a nonwoven seamless continuous tube which comprises:
- (a) a meltblowing die having a row of orifices comprising first and second groups;
- (b) a rotating mandrel positioned in alignment with the orifice groups;
- (c) means for delivering and extruding a polymer melt through the first group of orifices to form a first seamless filament layer on the mandrel;
- (d) means for moving the first filament layer under the second group of orifices;
- (e) means for delivering and extruding a polymer melt through the second group of orifices at a rate different than polymer flow through the first group of orifices to form a second seamless layer of filaments on the first layer, thereby forming a two-layered tube;
- and
- (f) means for withdrawing the tube from the mandrel.
Apparatus for manufacturing a nonwoven seamless, multi-layer web which comprises:
- (a) a meltblowing die having a row of orifices comprising 5 or more groups arranged in end-to-end relation;
- (b) a rotating mandrel positioned in alignment with the row of orifices;
- (c) means for flowing polymer melt through each orifice group so that the polymer flow rate through each orifice of one group is different from the polymer flow rate through each orifice of the other groups thereby forming a layer of meltblown fibers from each group and having a different average fiber size from an adjacent layer, said layers forming a seamless tube as the mandrel rotates;
- and
- (d) means for withdrawing the tube from the mandrel.
An apparatus for manufacturing a nonwoven seamless composite tube which comprises:
- (a) die for meltblowing a polymer melt and having a row of orifices comprising a first and second group;
- (b) a rotating mandrel positioned in alignment with the orifice groups;
- (c) a first pump for delivering and extruding a polymer melt through the first orifice group to form a seamless less filament layer on the mandrel;
- (d) means for moving the first filament layer under the second group of orifices;
- (e) a second pump for delivering and extruding through the second orifice group a polymer melt of different composition than that delivered by the first pump to form around the first filament layer a second filament layer of different composition, thereby forming a two layer composite tube;
- and
- (f) means for withdrawing the tube from the mandrel.
A process for manufacturing a seamless tubular non-woven tube which comprises:
- (a) meltblowing a molten thermoplastic polymer from a first group of orifices onto a rotating mandrel to form a first continuous layer of meltblown filaments thereon;
- (b) passing the first layer along the mandrel under a second group of orifices;
- (c) meltblowing a molten thermoplastic polymer from a second group of orifices onto the first layer of the rotating mandrel as the first layer moves along the mandrel under the second group of orifices to form a second continuous layer on the first layer, thereby forming a multi-layer seamless, continuous tube, each layer differing from the other layer in fiber size or composition;
- and
- (d) withdrawing the tube from the mandrel.
An apparatus for producing seamless continuous non-woven tubes which includes a die for spinning filaments onto a rotating mandrel to form a continuous tube of nonwoven filaments thereon, the improvement wherein the mandrel comprises:
- (a) a hollow outer shaft;
- (b) an inner shaft extending through the outer shaft and having an end portion extending axially outwardly from the outer shaft, the end portion being threaded and in combination with the outer shaft being positioned in relation to the die to receive and wind filaments thereon;
- (c) means for rotating the inner and outer shafts independently at the rate for receiving a layer of filaments on the outer shaft and the end portion of the inner shaft;
- and
- (d) means for rotating the inner shaft at an rpm different than the outer shaft whereby the rotating threads of the end portion of the inner shaft engages the tube of nonwoven filaments forcing the tube to move axially along the outer shaft.
Dependencies are inferred from the claim text.