Method of preparing water-soluble non-woven fabric

Abstract

The water-soluble non-woven fabric according to the present invention is prepared by (a) preparing a non-woven fabric with cellulose fibers, (b) mercerizing the non-woven fabric with aqueous sodium hydroxide in a solvent in a bath, (c) carrying out etherification of the mercerized fabric by adding monochloro acetic acid solution, (d) neutralizing the fabric with a hydrochloric acid solution to be a pH of about 6.0 to 9.0 in the bath, and (e) post-treating the fabric through dehydration and drying. The dissolving time of the non-woven fabric can be controlled depending on the amounts of the solid monochloro acetic acid, solid sodium hydroxide and hydrochloric acid to be used.

What is claimed is:  
     
         1 . A method of preparing a water-soluble non-woven fabric, comprising the steps of: 
 (a) preparing a non-woven fabric being made of cellulose fibers;    (b) mercerizing the non-woven fabric with aqueous sodium hydroxide in a solvent in a bath;    (c) carrying out etherification of the mercerized fabric by adding monochloro acetic acid solution;    (d) neutralizing the fabric with a hydrochloric acid solution to be a pH of about 6.0 to 9.0 in the bath; and    (e) post-treating the fabric through dehydration and drying.    
     
     
         2 . The method as defined in  claim 1 , wherein said non-woven fabric is a woven fabric, a knitted fabric, a sheet or a film being made of cellulose fibers.  
     
     
         3 . The method as defined in  claim 1 , wherein said solvent is an alcohol or an ester.  
     
     
         4 . The method as defined in  claim 1 , wherein said alcohol is selected from the group consisting of methyl alcohol, ethyl alcohol and isopropyl alcohol.  
     
     
         5 . The method as defined in  claim 1 , wherein said mercerization (step (b)) is conducted in aqueous sodium hydroxide prepared by dissolving about 50-80 g of solid sodium hydroxide in powder per 100 g of the non-woven fabric in about 30-180 g of water and in a solvent of about 600-1000 ml per 100 g of the non-woven fabric at the temperature of about 30-60° C. for about 1-4 hours.  
     
     
         6 . The method as defined in  claim 1 , wherein said etherification (step (c)) is conducted by adding monochloro acetic acid solution prepared by dissolving about 10-120 g of monochloro acetic acid in solid per 100 g of the non-woven fabric in about 20-720 g of a solvent at the temperature of about 60-90° C. for about 1-3 hours.  
     
     
         7 . The method as defined in  claim 1 , wherein said neutralization (step (d)) is conducted by adding hydrochloric acid solution prepared by mixing about 10-40 ml of hydrochloric acid with about 300 -  500  ml of a solvent per 100 g of the non-woven fabric to be the pH in the range of about 6.0-9.0.  
     
     
         8 . The method as defined in  claim 1 , wherein said neutralization (step (d)) is conducted in a separate reactor filled with hydrochloric acid solution prepared by mixing about 10-40 ml of hydrochloric acid with about 300-500 ml of a solvent per 100 g of the non-woven fabric to be the pH in the range of about 6.0-9.0.  
     
     
         9 . The method as defined in  claim 1 , wherein said drying in step (e) is conducted in a dryer in the range of about 50-150° C.  
     
     
         10 . The method as defined in  claim 6 , wherein said monochloro acetic acid in solid is used in the amount of about 10-40 g of per 100 g of the non-woven fabric.  
     
     
         11 . The method as defined in  claim 6 , wherein said monochloro acetic acid in solid is used in the amount of about 40-80 g of per 100 g of the non-woven fabric.  
     
     
         12 . The method as defined in  claim 6 , wherein said monochloro acetic acid in solid is used in the amount of about 80-120 g of per 100 g of the non-woven fabric.  
     
     
         13 . A water-soluble non-woven fabric which is prepared in accordance with the method of  claim 1 .  
     
     
         14 . A water-soluble non-woven fabric which is prepared in accordance with the method of  claim 10  and has a dissolving time of at least 1 month.  
     
     
         15 . A water-soluble non-woven fabric which is prepared in accordance with the method of  claim 11  and has a dissolving time between at least 2 hours and at most 1 month.  
     
     
         16 . A water-soluble non-woven fabric which is prepared in accordance with the method of  claim 12  and has a dissolving time of at most 2 hours.