Apparatus and method for producing non-woven webs with high filament velocity

A process for forming a spunbond, non-woven polymeric fabric from a plurality of polymeric extruded filaments, comprising the steps of:

• (a) extruding a plurality of filaments by melt spinning through a spinneret from a thermoplastic polymer;
• (b) drawing said filaments by a drawing means positioned below said spinneret using air pressure, applying said drawing force at a predetermined distance between 5 cm and 150 cm from said spinneret, said predetermined distance between said spinneret and said drawing means chosen to produce an air drag force having a magnitude which produces a filament velocity in the range of 3500 meters/minute to 8000 meters/minute or more on said filaments;
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• (b1) creating low air drag on said filaments to produce a high filament velocity based on the reduced air drag on the filaments resulting from the predetermined distance between the spinneret and the drawing means;
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• (c) forming a web on a web forming means positioned below said drawing means, whereby the denier size of the filaments and the net drawing force on the filaments can be controlled by the distance between the drawing means and the spinneret.

A plurality of filaments forming a spunbond, non-woven fabric web, produced by the process comprising the steps of:

• (a) extruding a plurality of filaments by melt spinning through a spinneret from a thermoplastic polymer;
• (b) drawing said filaments with a drawing force by a drawing means positioned below said spinneret using air pressure, applying said drawing force at a predetermined distance between 5 cm and 150 cm from said spinneret selected to produce low air drag on said filaments, said drawing force combined with said air drag having a magnitude which produces a filament velocity in the range of 3000 meters/minute to 8000 or more meters/minute filament velocity;
• and
• (c) forming a web on a web forming means positioned below said drawing means, whereby the denier size of the filaments can be controlled by the distance between the drawing means and the spinneret.

A process to increase filament velocity while forming a spunbond, non-woven, polymeric fabric from a plurality of polymeric extruded filaments comprising the steps of:

• extruding a plurality of filaments by melt-spinning through a spinneret from a thermoplastic polymer;
• drawing the filaments with a first drawing force created on said filaments within a drawing slot by a high velocity stream of air and a second drawing force created by form drag on said filaments below said drawing unit slot;
• producing a net spin line force balance on said filaments by providing a distance from the drawing slot to the spinneret to reduce the air drag above said drawing slot, said spin line force combined with said first drawing force and said second drawing force to produce high velocity filaments;
• and
• positioning a web forming means below said drawing unit slot for collecting the filaments and forming the filaments into a non-woven web.

A process for forming a spunbond, non-woven, polymeric fabric from a plurality of polymeric extruded filaments spun at high velocity comprising the steps of:

• extruding a plurality of strategically oriented filaments from a thermoplastic polymer by melt-spinning through a spinneret;
• drawing said filaments by a net drawing force generated by a drawing means positioned at a predetermined distance from said spinneret to provide low air drag and high filament velocity,
• said drawing means providing internal air pressure within said drawing means and high velocity air below said drawing means creating a net drawing force on said filaments;
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• selecting the distance between said spinneret and said drawing means to reduce the air drag force on said filaments to increase the net drawing force on said filaments to increase filament velocity;
• and
• forming a filament web of a spunbond, non-woven polymeric fabric by depositing said extruded filaments on a web forming means positioned at a pre-selected distance below said drawing unit.

A process for forming a spunbond non-woven, polymeric fabric from a plurality of polymeric extruded filaments for providing high filament speed comprising the steps of:

• extruding a plurality of filaments from a thermoplastic polymer by melt-spinning through a spinneret;
• drawing said filaments with a drawing force by a drawing means positioned at a preselected distance from said spinneret, said preselected distance chosen to reduce air drag on said filaments to increase the net drawing force on said filaments;
• selecting the distance between the spinneret and the drawing means to produce an air drag force on the filament spin line having a magnitude which produces a filament speed in the range of 3000 meters per minute to 8000 or more meters per minute for increasing throughput and filament tensile strength and for increasing the net drawing force on the filaments to increase filament velocity;
• and
• forming a filament web of a spunbond, non-woven polymeric fabric by depositing said extruded filaments on a web forming means positioned below said drawing means.

An apparatus for forming a non-woven web from extruded polymer filaments comprising:

• a polymer extruder including melt spinning component having a spinneret with one or more rows of closely spaced orifices for extruding a plurality of continuous polymeric filaments;
• a drawing unit including a longitudinally disposed elongated slot positioned below said spinneret along substantially the entire longitudinal length of said drawing unit;
• one or more air nozzles for supplying high velocity streams of air, said air nozzle(s) having an outlet communicating with said drawing unit elongated slot along substantially the longitudinal length of said drawing unit, said air nozzle being disposed to provide high velocity streams of air in at least one predetermined direction downwardly within said slot for introducing downwardly directed streams of air into said slot, said drawing unit slot including a bottom opening, the distance between said air nozzle and said bottom of said drawing unit slot opening being less than 210 mm to allow air generated at high velocity within said drawing unit to exit said drawing unit slot bottom opening to provide additional force on said filaments after said filaments leave said drawing unit;
• and
• web-forming platform positioned below said drawing unit for collecting the filaments for formation into a non-woven fabric web, whereby high velocity air exiting said drawing unit slot bottom opening interacts with said filaments exiting said drawing unit bottom slot causing said filaments to wave in a waving pattern below said slot bottom opening creating a downward force on said filaments thereby increasing the drawing force on said filaments.

A process to provide high velocity filaments while forming a spunbond, non-woven, polymeric fabric from a plurality of polymeric extruded filaments comprising the steps of:

• (a) extruding a plurality of filaments by melt-spinning through a spinneret from a thermoplastic polymer;
• (b) drawing the filaments with a net drawing force created by a combination of a first drawing force created by a first air stream generated by high velocity air directed on filaments within a drawing unit slot and a second drawing force created by form drag on said filaments beneath the drawing unit slot resulting from high velocity air exiting the drawing unit slot bottom, said form drag creating a waving pattern of filaments beneath the drawing unit slot increasing the downward force on said filaments;
• (c) reducing the air drag on said filaments above said drawing unit by providing a predetermined distance between said spinneret and said drawing unit to produce high velocity filaments during the spunbond operation;
• (d) collecting said filaments on a web forming means below said drawing unit.

A process for forming a spunbond, non-woven web from extruded polymer filaments comprising the steps of:

• (a) extruding a plurality of filaments by melt spinning through a spinneret from a thermoplastic polymer;
• (b) drawing said filaments by a drawing means positioned a predetermined distance from said spinneret producing low air drag on said filaments;
• (c) producing a predetermined filament velocity in the range of 3000 meters/minute to 8,000 or more meters/minute by creating a net drawing force on said filaments by producing low air drag on said filaments between said spinneret and said drawing means;
• (d) creating a first drawing force on said filaments within said drawing means slot;
• and creating a second drawing force on said filaments below said drawing means slot, the combination of said low air drag, and said first and second drawing forces producing said predetermined filament velocity;
• and
• (e) collecting the filaments on a web forming means for formation into a non-woven fabric web.