Spinneret for multi-row coaxial spunbond and/or melt-blown type plant

Abstract

There is provided a spinneret ( 1 ) for a multi-row coaxial spunbond and/or melt-blown type plant developing along a main axis ( 1 a ) and a main plane ( 1 b ), defining a vertical axis ( 1 c ) perpendicular to the main axis and plane ( 1 a, 1 b ) and comprising a first end ( 10 ) adapted to interface with a polymeric fluid distributor of a multi-row coaxial spunbond and/or melt-blown type plant; a second end ( 11 ) arranged at a side of the spinneret ( 1 ) opposite the first end ( 10 ) with respect to the main plane ( 1 a ) at which the polymer fluid exits from the spinneret ( 1 ) in the form of polymer filaments; and a plurality of acceleration conduits ( 2 ) extending at least from the first end ( 10 ) to the second end ( 11 ) each along its own dispensing axis ( 2 a ), each adapted to dispense a respective polymer filament along the dispensing axis ( 2 a ) and distributed both along a distribution axis ( 2 b ) transverse to the main axis ( 1 a ) and the vertical axis ( 1 c ) so as to create a first row ( 2 ′), and parallel to the main axis ( 1 a ) so as to make at least a second row ( 2 ″) offset with respect to the first row ( 2 ′) along the main axis ( 1 a ); and wherein at least one of the dispensing axes ( 2 a ) of the acceleration conduits ( 2 ) of the first row ( 2 ′) defines a first angle of inclination (α′) with respect to the main plane ( 1 b ) other than 90° and at least one of the dispensing axes ( 2 a ) of the acceleration conduits ( 2 ) of the second row ( 2 ′) defines a second angle of inclination (α′) with respect to the main plane ( 1 b ) different from the first angle of inclination (α′).

1 . Spinneret ( 1 ) for multi-row coaxial spunbond and/or melt-blown type plant developing along a main axis ( 1   a ) and a main plane ( 1   b ), defining a vertical axis ( 1   c ) perpendicular to said main axis ( 1   a ) and said main plane ( 1   b ) and comprising:
 a first end ( 10 ) adapted to interface with a polymeric fluid distributor of a multi-row coaxial spunbond and/or melt-blown type plant;   a second end ( 11 ) arranged at a side of said spinneret ( 1 ) opposite said first end ( 10 ) with respect to said main plane ( 1   b ) at which said polymeric fluid exits from said spinneret ( 1 ) in the form of polymeric filaments; and   a plurality of acceleration conduits ( 2 )
 extending at least from said first end ( 10 ) to said second end ( 11 ) each along its own dispensing axis ( 2   a ), 
 adapted to dispense each one a respective said polymeric filament along said dispensing axis ( 2   a ) and 
 distributed both along a distribution axis ( 2   b ) transverse to said main axis ( 1   a ) and said vertical axis ( 1   c ) in such a way as to create a first row ( 2 ′), and parallel to said main axis ( 1   a ), creating at least a second row ( 2 ″) offset with respect to said first row ( 2 ′) along said main axis ( 1   a ); 
   
       characterized in that:
 at least one of said dispensing axes ( 2   a ) of said acceleration conduits ( 2 ) of said first row ( 2 ′) defines a first angle of inclination (α′) with respect to said main plane ( 1   b ) other than 90° and 
 at least one of said dispensing axes ( 2   a ) of said acceleration conduits ( 2 ) of said second row ( 2 ′) defines a second angle of inclination (α″) with respect to said main plane ( 1   b ) different from said first angle of inclination (α′). 
 
     
     
         2 . Spinneret ( 1 ) according to  claim 1 , wherein said dispensing axes ( 2   a ) of all said acceleration conduits ( 2 ) of said first row ( 2 ′) and/or said second row ( 2 ″) respectively define a same said first angle of inclination (α′) and/or the same said second angle of inclination (α″). 
     
     
         3 . Spinneret ( 1 ) according to  claim 1 , wherein one or more of said second angles of inclination (α″) are equal to 90°. 
     
     
         4 . Spinneret ( 1 ) according to  claim 1 , wherein said second angle of inclination (α″) is opposite or additional to said first angle of inclination (α′). 
     
     
         5 . Spinneret ( 1 ) according to  claim 1 , wherein said first angle of inclination (α′) is comprised between 60° and 90°. 
     
     
         6 . Spinneret ( 1 ) according to  claim 1 , wherein one or more of said acceleration conduits ( 2 ) comprises at least one closed inner surface ( 3 ), developing around said dispensing axis ( 2   a ) and defining a plurality of mutually identical outlines ( 4 ) arranged in succession along said dispensing axis ( 2   a ); wherein said outline ( 4 ) is determined on a section plane ( 2   c ) normal to said dispensing axis ( 2   a ); wherein said outline ( 4 ) defines a first extension area on said section plane ( 2   c ); wherein said outline ( 4 ) is inscribable in a circle determined on said section plane ( 2   c ); and wherein said circle defines a second extension area on said section plane ( 2   c );
 said first extension area being less than 90% of said second extension area.   
     
     
         7 . Spinneret ( 1 ) according to  claim 6 , wherein said first extension area is less than 60% of said second extension area. 
     
     
         8 . Spinneret ( 1 ) according to  claim 1 , wherein said outline ( 4 ) is convex and defines at least a first maximum dimension ( 4   a ) and a second maximum dimension ( 4   b ) perpendicular to said first dimension ( 4   a ) and less than 90% of said first dimension ( 4   a ). 
     
     
         9 . Spinneret ( 1 ) according to  claim 8 , wherein said second dimension ( 4   b ) is less than 60% of said first dimension ( 4   a ). 
     
     
         10 . Spinneret ( 1 ) according to  claim 2 , wherein said outline ( 4 ) defines an almost equilateral triangular or almost rectangular shape. 
     
     
         11 . Spinneret ( 1 ) according to  claim 6 , wherein said outline ( 4 ) is concave and includes at least one convex portion ( 40 ) identifiable within said outline ( 4 ) in such a way as to be delimited by at least part of said outline ( 4 ) and defining at least a third maximum dimension ( 40   a ) and a fourth maximum dimension ( 40   b ), perpendicular to said third dimension ( 40   a ) and less than 90% of said third dimension ( 40   a ). 
     
     
         12 . Spinneret ( 1 ) according to  claim 11 , wherein said fourth dimension ( 40   b ) is less than 60% of said third dimension ( 40   a ). 
     
     
         13 . Spinneret ( 1 ) according to  claim 11 , wherein said outline ( 4 ) is formed by two or more said mutually crossed convex portions ( 40 ). 
     
     
         14 . Spinneret ( 1 ) according to  claim 13 , wherein said outline ( 3 ) defines a cross shape having three to five tips. 
     
     
         15 . Spinneret ( 1 ) according to  claim 14 , comprises a plurality of said acceleration conduits ( 2 ) all defining a same said outline ( 4 ), or said mutually different outlines ( 4 ) and/or of which one or more of circular type.