Nonwoven fabric, and process for producing the same

Abstract

In a fibrous web, press-welded line portions are formed, and press-welded dot portions are formed in portions other than the press-welded line portions. The formation of the press-welded line portions makes it possible to raise the surface of the fibrous web, to increase the bulkiness of the nonwoven fabric and to make the nonwoven fabric soft. Further, figures are drawn by the press-welded line portions, whereby the nonwoven fabric comes to have an excellent appearance in comparison to a conventional nonwoven fabric.

What is claimed is:  
     
         1 . A nonwoven fabric characterized in that 
 a fibrous web formed of thermoplastic fibers or containing thermoplastic fibers is partially pressed and heated to form recessed press-welded portions, the fibers in the portions other than said recessed portions being raised;    said press-welded portions are continuous lines or uncontinuous lines which give a pattern of figures, characters or signals containing at least curved portions or square portions, or a pattern of a combination thereof; and    a plurality of press-welded dot portions are formed in the portions other than the continuous line or uncontinuous line press-welded portions such that said press-welded dot portions do not overlap with the continuous line or uncontinuous line press-welded portions.    
     
     
         2 . The nonwoven fabric according to    claim 1   , wherein the base weight of the fibrous web is at least 15 g/m 2  and at most 45 g/m 2 , the specific volume of the press-welded portions formed in the fibrous web is at least 3 cm 3 /g and at most 10 cm 3 /g, and the specific volume of the non-press-welded portions is at least 10 cm 3 /g and at most 30 cm 3 /g.  
     
     
         3 . The nonwoven fabric according to    claim 1   , wherein a portion surrounded by the continuous line or the uncontinuous line press-welded portion is formed, and the fibers are raised in this surrounded portion.  
     
     
         4 . The nonwoven fabric according to    claim 1   , wherein the total area of the press-welded dot portions is the same as, or less than, the total area of the continuous line or uncontinuous line press-welded portions.  
     
     
         5 . The nonwoven fabric according to    claim 1   , wherein the continuous line or uncontinuous line press-welded portions are spaced apart from the press-welded dot portions at a space of at least 1 mm and at most 5 mm.  
     
     
         6 . The nonwoven fabric according to    claim 1   , wherein the starting fibers of the fibrous web have a square cross-sectional shape.  
     
     
         7 . The nonwoven fabric according to    claim 1   , wherein the fibers are melted in the press-welded portions, and said portions become filmy.  
     
     
         8 . The nonwoven fabric according to    claim 7   , wherein a color sheet is laminated on the reverse surface of the nonwoven fabric, and the color of the color sheet laminated on the reverse surface is seen through the press-welded portions of the nonwoven fabric.  
     
     
         9 . A process for producing a nonwoven fabric comprising the following steps: 
 a step of forming a fibrous web with thermoplastic fibers or fibers containing thermoplastic fibers,    a step of feeding said fibrous web between a hot roller provided on the surface with projected portions containing continuous lines or uncontinuous lines by which to form figures, characters or symbols having at least curved portions or square portions, or a combination thereof, and a hot roller having a smooth surface, and    a step of holding the fibrous web between the hot roller provided on the surface with the projected portions and the hot roller having the smooth surface, and press-welding the fibers of the fibrous web with the projected portions to partially recess the fibrous web and form press-welded portions.    
     
     
         10 . The process of producing a nonwoven fabric according to    claim 9   , wherein a plurality of projected dot portions are formed on the hot roller besides the continuous line or uncontinuous line projected portions.  
     
     
         11 . The process of producing a nonwoven fabric according to    claim 9   , wherein a colorless fibrous web is laminated on a dyed or colored thermoplastic sheet, the laminate is held between both of the hot rollers, and the thermoplastic sheet and the fibrous web of the laminate are together press-welded with the projected portions of the hot roller to form press-welded portions.  
     
     
         12 . The process according to    claim 9   , wherein a fibrous web formed of colorless fibers is laminated on a fibrous web formed of dyed or colored fibers, the thus-laminated fibrous webs are held between both of the hot rollers, and the colored fibrous web and the colorless fibrous web are partially press-welded together with the projected portions of the hot roller to form press-welded portions.