Water-disintegrable nonwoven fabric and process for producing same

Abstract

Disclosed is water-disintegrable nonwoven fabric which comprises 15-30 mass % regenerated cellulose fibers having a fiber length of 3-4 mm and a fineness of 0.3 dtex or less and 70-85 mass % pulp, has a basis weight of 35-50 g/m 2 , has a tendency to disentanglement of 100 seconds or less when examined by a disentanglement test according to JIS P 4501:1993, and has a wet tensile strength of 1.2 N/25 mm or greater. The water-disintegrable nonwoven fabric combines wet tensile strength during use with water disintegrability after use.

1 - 3 . (canceled) 
     
     
         4 . A water-disintegrable nonwoven fabric comprising 15 to 30 wt % of regenerated cellulose fibers having a fiber length of 3 to 4 mm and a fineness of 0.3 dtex or less and 70 to 85 wt % of pulp, having a basis weight of 35 to 50 g/m 2 , having a disintegrability within 100 sec. as measured in accordance with JIS P 4501:1993, and having a wet tensile strength of 1.2 N/25 mm or greater, wherein the nonwoven fabric has a concave-convex structure on one side and does not have a concave-convex structure on the other side. 
     
     
         5 . The water-disintegrable nonwoven fabric according to  claim 4 , wherein the regenerated cellulose fibers has a fineness of 0.1 to 0.3 dtex. 
     
     
         6 . The water-disintegrable nonwoven fabric according to  claim 4 , wherein the concave-convex structure has a plurality of ridges and a plurality of grooves alternately arranged in parallel. 
     
     
         7 . The water-disintegrable nonwoven fabric according to  claim 6 , wherein the concave-convex structure has a difference in height between tops of the plurality of ridges and tops of the plurality of grooves of 0.15 to 0.40 mm. 
     
     
         8 . The water-disintegrable nonwoven fabric according to  claim 6 , wherein the plurality of ridges have a pitch of 0.5 to 1.0 mm. 
     
     
         9 . A process for producing the water-disintegrable nonwoven fabric according to  claim 4 , comprising:
 (A) subjecting a slurry comprising regenerated cellulose fibers having a fiber length of 3 to 4 mm and a fineness of 0.3 dtex or less and pulp at a weight ratio of 15:85 to 30:70 to wet papermaking at a fiber basis weight of 35 to 50 g/m 2 ,   (B) subjecting the web obtained in step (A) to a hydroentangling treatment by injecting water streams from a nozzle having a plurality of nozzle holes aligned in the width direction of the web at an energy of 0.05 kWh/kg to 0.1 kWh/kg to entangle fibers with each other, and   (C) drying the web subjected to the hydroentangling treatment.   
     
     
         10 . The process according to  claim 9 , wherein the nozzle has a hole pitch of 0.5 to 1.0 mm. 
     
     
         11 . The process according to  claim 9 , wherein the concave-convex structure has a plurality of ridges and a plurality of grooves alternately arranged in parallel. 
     
     
         12 . The process according to  claim 11 , wherein the concave-convex structure has a difference in height between tops of the plurality of ridges and tops of the plurality of grooves of 0.15 to 0.40 mm.