Forming shaped fiber fabrics

Abstract

A fibrous product including a mixture of different shaped fibers is formed utilizing a spin pack assembly including a spinneret with at least two spinneret orifices having different cross-sections. In addition, the formation of the fibrous product is enhanced by controlling the pressure drop upstream from the spinneret orifices, which in turn facilitates effective control of fiber denier. A metering/distribution plate is preferably provided in the spin pack with channels having selected dimensions that control the pressure drop of molten polymer flowing through the spin pack. The metering/distribution plate can be retrofitted into existing systems and easily exchanged with other metering/distribution plates to enhance formation of the fibrous product with different fiber shapes.

1 . A spinneret comprising at least two spinneret orifices having geometries different from each other.  
     
     
         2 . The spinneret of  claim 1 , wherein at least one spinneret orifice has a geometry that is configured to form a hollow fiber.  
     
     
         3 . The spinneret of  claim 1 , wherein the geometries of the spinneret orifices include round and multi-lobal.  
     
     
         4 . The spinneret of  claim 3 , wherein the geometries of the spinneret orifices include trilobal.  
     
     
         5 . The spinneret of  claim 3 , wherein at least some of the round spinneret orifices are located closer to peripheral portions of the spinneret in relation to all multi-lobal spinneret orifices.  
     
     
         6 . The spinneret of  claim 3 , wherein only round spinneret orifices are located within a selected section disposed at each longitudinal end portion of the spinneret.  
     
     
         7 . The spinneret of  claim 3 , wherein only round spinneret orifices are located within a central portion of the spinneret.  
     
     
         8 . The spinneret of  claim 1 , wherein at least one group of the multi-lobal spinneret orifices are formed along an outlet surface the spinneret such that a lobe of a multi-lobal fiber extruded from each multi-lobal spinneret orifice of the at least one group is aligned to face in a direction of a quench medium source that directs a quench medium toward fibers extruded from the spinneret.  
     
     
         9 . The spinneret of  claim 1 , wherein the spinneret includes a first group of multi-lobal spinneret orifices and a second group of multi-lobal spinneret orifices that have the same geometric shape as the first group of multi-lobal spinneret orifices, the multi-lobal orifices of the first group being aligned along an outlet surface of the spinneret at a selected angle of rotation with respect to the multi-lobal spinneret orifices of the second group.  
     
     
         10 . The spinneret of  claim 9 , wherein the multi-lobal spinneret orifices of the first group are aligned at a 180° rotation with respect to the multi-lobal spinneret orifices of the second group.  
     
     
         11 . The spinneret of  claim 1 , wherein at least 50% of the spinneret orifices have a multi-lobal geometry.  
     
     
         12 . The spinneret of  claim 1 , wherein at least 75% of the spinneret orifices have a multi-lobal geometry.  
     
     
         13 . The spinneret of  claim 1 , wherein at least 80% of the spinneret orifices have a multi-lobal geometry.  
     
     
         14 . A metering/distribution plate for use in a spin pack assembly that comprises a spinneret including a first set of spinneret orifices and a second set of spinneret orifices, the spinneret orifices of the first set having geometries that are different from geometries of the spinneret orifices of the second set, the metering/distribution plate comprising: 
 a first set of passages configured to deliver molten polymer flowing through the spin pack assembly to the first set of spinneret orifices; and    a second set of passages configured to deliver molten polymer flowing through the spin pack assembly to the second set of spinneret orifices;    wherein the passages for each set are selected to facilitate the formation of extruded fibers through the first and second sets of spinneret orifices having selected deniers.    
     
     
         15 . The metering/distribution plate of  claim 14 , wherein the passages of the plate are vertical through-holes that have been drilled in the plate.  
     
     
         16 . The metering/distribution plate of  claim 14 , wherein the passages of the plate include horizontally formed channels disposed along a first surface of the plate and vertical through-holes in fluid communication with the channels and extending to a second surface of the plate.  
     
     
         17 . The metering/distribution plate of  claim 16 , wherein the channels have a channel width to a channel depth ratio of about 1.5:1 to about 15:1.  
     
     
         18 . A spin pack assembly comprising: 
 a spinneret comprising a first set of spinneret orifices and a second set of spinneret orifices, the spinneret orifices of the first set having geometries different from geometries of the spinneret orifices of the second set; and    a metering/distribution plate configured to deliver molten polymer flowing through the spin pack assembly to the spinneret, the metering/distribution plate comprising a a first set of passages configured to deliver molten polymer flowing through the spin pack assembly to the first set of spinneret orifices, and a second set of passages configured to deliver molten polymer flowing through the spin pack assembly to the second set of spinneret orifices, wherein the passages for each set are selected to facilitate the formation of extruded fibers through the first and second sets of spinneret orifices having selected deniers.    
     
     
         19 . The spin pack assembly of  claim 18 , wherein the geometries of the spinneret orifices include round and multi-lobal.  
     
     
         20 . The spin pack assembly of  claim 18 , wherein the spin pack assembly is configured to receive different metering/distribution plates including different sets of passages having different passage dimensions.  
     
     
         21 . A method of forming a mixed filament product including polymer fibers with different cross-sectional geometries, the method comprising: 
 providing a spin pack assembly including a spinneret with a first set of spinneret orifices and a second set of spinneret orifices, the spinneret orifices of the first set having geometries that are different from geometries of the spinneret orifices of the second set.    
     
     
         22 . The method of  claim 21 , wherein the geometries of the spinneret orifices include round and multi-lobal.  
     
     
         23 . The method of  claim 22 , wherein at least one group of the multi-lobal spinneret orifices are formed in the spinneret such that a lobe of a multi-lobal fiber extruded from each multi-lobal spinneret orifice of the at least one group is aligned to face in a direction of a quench medium source that directs a quench medium toward fibers extruded from the spinneret.  
     
     
         24 . The method of  claim 21 , further comprising: 
 providing a metering/distribution plate for the spin pack assembly, the metering/distribution plate being configured to deliver molten polymer flowing through the spin pack assembly to the spinneret and including a first set of passages configured to deliver molten polymer flowing through the spin pack assembly to the first set of spinneret orifices, and a second set of passages configured to deliver molten polymer flowing through the spin pack assembly to the second set of spinneret orifices.    
     
     
         25 . The method of  claim 24 , further comprising: 
 providing the passages of the first set of the metering/distribution plate with selected dimensions to control the deniers of fibers extruded from the first set of spinneret orifices; and    providing the passages of the second set of the metering/distribution plate with selected dimensions to control the deniers of fibers extruded from the second set of spinneret orifices.    
     
     
         26 . The method of  claim 24 , further comprising: 
 modifying at least one operating parameter selected from: polymer throughput through the spin pack assembly, fiber cross-sectional geometry of fibers formed from the spinneret, the arrangement of spinneret orifices along the spinneret, a temperature of polymer material flowing through the spin pack assembly, denier of fibers formed from at least one of the first and second sets of spinneret orifices, the number of spinneret orifices in at least one of the first and second sets of spinneret orifices, and polymer material of fibers extruded from the spinneret; and    replacing the metering/distribution plate in the spin pack assembly with a different metering/distribution plate including selected passage dimensions to facilitate selective control of the deniers of fibers extruded from the spinneret after the modification of the at least one operating parameter.    
     
     
         27 . The method of  claim 21 , wherein fibers formed from the spinneret include at least one of: fibers having different cross-sectional geometries but with the same one or more polymer components, and fibers having different cross-sectional geometries and different polymer components.  
     
     
         28 . The method of  claim 21 , wherein at least some of the fibers formed from the spinneret include multi-polymer components.  
     
     
         29 . A spunlaid system comprising: 
 a spin pack assembly comprising: 
 a spinneret comprising a first set of spinneret orifices and a second set of spinneret orifices, the spinneret orifices of the first set having geometries different from geometries of the spinneret orifices of the second set; and  
 a metering/distribution plate configured to deliver molten polymer flowing through the spin pack assembly to the spinneret, the metering/distribution plate comprising a a first set of passages configured to deliver molten polymer flowing through the spin pack assembly to the first set of spinneret orifices, and a second set of passages configured to deliver molten polymer flowing through the spin pack assembly to the second set of spinneret orifices, wherein the channels for each set are selected to facilitate the formation of extruded fibers through the first and second sets of spinneret orifices having selected deniers; and  
   a quench source aligned and configured to direct at least one source of quench medium toward fibers extruded from the spinneret.    
     
     
         30 . The system of  claim 29 , wherein at least one group of the multi-lobal spinneret orifices are formed along an outlet surface the spinneret such that a lobe of a multi-lobal fiber extruded from each multi-lobal spinneret orifice of the at least one group is aligned to face in a direction of a quench medium source that directs a quench medium toward fibers extruded from the spinneret.  
     
     
         31 . The system of  claim 29 , further comprising: 
 a plurality of metering pumps to independently meter molten polymer material to the spin pack assembly.    
     
     
         32 . The system of  claim 31 , wherein a first metering pump meters a molten polymer material to the first set of passages of the metering/distribution plate, and a second metering pump meters molten polymer material to the second set of passages of the metering/distribution plate.