Water-dispersible fibers and fibrous articles

Abstract

Disclosed are water-dispersible fibers derived from sulfopolyesters having a Tg of at least 25° C. The fibers may contain a single sulfopolyester or a blend of a sulfopolyester with a water-dispersible or water-nondispersible polymer. Also disclosed are fibrous articles from the water-dispersible fibers. The fibrous articles include water-dispersible nonwoven webs, fabrics, and multilayered articles such as wipes, gauze, tissue, diapers, panty liners, sanitary napkins, bandages, and surgical dressings. Also disclosed is a process for water-dispersible fibers and nonwoven fabrics. The fibers and fibrous articles have further applications in flushable personal care and cleaning products, disposable protective outerwear, and laminating binders.

We claim:  
     
         1 . A water-dispersible fiber comprising: 
 A) a sulfopolyester having a glass transistion temperature (Tg) of at least 25° C., said sulfpolyester comprising: 
 (i) residues of one or more dicarboxylic acids;  
 (ii) about 4 to about 40 mole %, based on the total repeating units, of residues of at least one sulfomonomer having 2 functional groups and one or more sulfonate groups attached to an aromatic or cycloaliphatic ring wherein said functional groups are hydroxyl, carboxyl, or a combination thereof;  
 (iii) one or more diol residues wherein at least 25 mole %, based on the total hydroxyl residues, is a poly(ethylene glycol) having a structure  
 H—(OCH 2 —CH 2 ) n —OH  
  wherein n is an integer in the range of 2 to about 500; and  
 (iv) 0 to about 25 mole %, based on the total repeating units, of residues of a branching monomer having 3 or more functional groups wherein said functional groups are hydroxyl, carboxyl, or a combination thereof;  
   (B) optionally, a water-dispersible polymer blended with said sulfopolyester; and    (C) optionally, a water-nondispersible polymer blended with said sulfopolyester with the proviso that said blend is an immiscible blend.    
     
     
         2 . The fiber according to  claim 1  in which said dicarboxylic acids are selected from the group consisting of aliphatic diacids, cycloaliphatic dicarboxylic acids, aromatic dicarboxylic acids, and combinations thereof.  
     
     
         3 . The fiber according to  claim 2  in which said dicarboxylic acids are selected from succinic, glutaric, adipic, azelaic, sebacic, fumaric, maleic, itaconic, 1,3-cyclohexane dicarboxylic, 1,4-cyclohexanedicarboxylic, diglycolic, 2,5-norbornanedicarboxylic, phthalic, terephthalic, 1,4-naphthalenedicarboxylic, 2,5-naphthalenedicarboxylic, 2,6-naphthalenedicarboxylic, 2,7-naphthalenedicarboxylic, diphenic, 4,4′-oxydibenzoic, 4,4′-sulfonyldibenzoic, isophthalic, and combinations thereof.  
     
     
         4 . The fiber according to  claim 3  in which said sulfomonomer is a metal sulfonate salt of a sulfophthalic acid, sulfoterephthalic acid, sulfoisophthalic acid, or combinations thereof.  
     
     
         5 . The fiber according to  claim 4  in which said diol residues are selected from ethylene glycol, diethylene glycol, triethylene glycol, poly(ethylene) glycols, propylene glycol, 1,3-propanediol, 2,4-dimethyl-2-ethylhexane-1,3-diol, 2,2-dimethyl-1,3-propanediol, 2-ethyl-2-butyl-1,3-propanediol, 2-ethyl-2-isobutyl-1,3-propanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 2,2,4-trimethyl-1,6-hexanediol, thiodiethanol, 1,2-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, 2,2,4,4-tetramethyl-1,3-cyclobutanediol, p-xylylenediol, and combinations thereof.  
     
     
         6 . The fiber according to  claim 5  in which said branching monomer is 1,1,1-trimethylol propane, 1,1,1-trimethylolethane, glycerin, pentaerythritol, erythritol, threitol, dipentaerythritol, sorbitol, trimellitic anhydride, pyromellitic dianhydride, dimethylol propionic acid, or combinations thereof.  
     
     
         7 . A water-dispersible fiber comprising: 
 A) a sulfopolyester having a glass transistion temperature (Tg) of at least 25° C., said sulfpolyester comprising: 
 (i) about 50 to about 96 mole % of a residue of isophthalic acid, based on the total acid residues;  
 (ii) about 4 to about 30 mole %, based on the total acid residues, of a residue of sodiosulfoisophthalic acid;  
 (iii) one or more diol residues wherein at least 25 mole %, based on the total diol residues, is a poly(ethylene glycol) having a structure  
 H—(OCH 2 —CH 2 ) n —OH  
  wherein n is an integer in the range of 2 to about 500;  
 (iv) 0 to about 20 mole %, based on the total repeating units, of residues of a branching monomer having 3 or more functional groups wherein said functional groups are hydroxyl, carboxyl, or a combination thereof;  
   (B) optionally, a first water-dispersible polymer blended with said sulfopolyester; and    (C) optionally, a water-nondispersible polymer blended with said sulfopolyester to form a blend with the proviso that said blend is an immiscible blend.    
     
     
         8 . The fiber according to  claim 7  comprising a first water-dispersible polymer blended with said sulfopolyester.  
     
     
         9 . The fiber according to  claim 7  comprising a water-nondispersible polymer blended to form a blend in which said blend is an immiscible blend.  
     
     
         10 . The fiber of  claim 7  in which said residue of isophthalic acid is about 75 to about 96 mole % and said diol residue is about 25 to about 95 mole % of a residue of diethylene glycol.  
     
     
         11 . The fiber of  claim 10  in which said fiber is a staple, monofilament, or a multifilament fiber and has a shaped cross-section.  
     
     
         12 . A fibrous article comprising the fiber of  claim 11 .  
     
     
         13 . The fibrous article of  claim 12  in which said article is selected from a yarn, fabric, melt blown web, spunbonded web, nonwoven fabric, and combinations thereof.  
     
     
         14 . The fibrous article of  claim 12  in which said article comprises one or more layers of fibers.  
     
     
         15 . The fibrous article of  claim 14  in which said article is a wipe, gauze, tissue, diaper, fiber-containing cleaning product, laminating binder, sanitary napkin, panty liner, tampon, training pants, incontinent product, bandage, or surgical dressing.  
     
     
         16 . The fibrous article of  claim 15  in which said article is flushable.  
     
     
         17 . The fibrous article of  claim 7  further comprising a water-dispersible film in which said water-dispersible film comprises a second water-dispersible polymer.  
     
     
         18 . The fibrous article of  claim 17  in which said second water-dispersible polymer comprises an additional sulfopolyester, said additional sulfopolyester comprising: 
 (i) about 50 to about 96 mole % of a residue of isophthalic acid, based on the total acid residues;  
 (ii) about 4 to about 30 mole %, based on the total acid residues, of a residue of sodiosulfoisophthalic acid;  
 (iii) one or more diol residues wherein at least 15 mole %, based on the total diol residues, is a poly(ethylene glycol) having a structure  
 H—(OCH 2 —CH 2 ) n —OH  
  wherein n is an integer in the range of 2 to about 500; and  
 (iv) 0 to about 20 mole %, based on the total repeating units, of residues of a branching monomer having 3 or more functional groups wherein said functional groups are hydroxyl, carboxyl, or a combination thereof.  
 
     
     
         19 . The fibrous article of  claim 18  in which said isophthalic acid residue of said additional sulfopolyester is about 75 to about 96 mole % and said diol residue of said additional sulfopolyester is about 25 to about 95 mole % of a residue of diethylene glycol.  
     
     
         20 . The fibrous article of  claim 18  further comprising a powder in which said powder comprises a third water-dispersible polymer.  
     
     
         21 . The fibrous article of  claim 18  in which said article is a wipe, gauze, tissue, diaper, fiber-containing cleaning product, sanitary napkin, panty liner, tampon, training pants, incontinent product, bandage, or surgical dressing.  
     
     
         22 . The fibrous article of  claim 21  in which said article is flushable.  
     
     
         23 . A process for water-dispersible fibers comprising: 
 I. providing a water-dispersible polymer composition comprising 
 (A) a sulfopolyester having a glass transistion temperature (Tg) of at least 25° C., said sulfopolyester comprising: 
 (i) residues of one or more dicarboxylic acids;  
 (ii) about 4 to about 40 mole %, based on the total repeating units, of residues of at least one sulfomonomer having 2 functional groups and one or more metal sulfonate groups attached to an aromatic or cycloaliphatic ring wherein said functional groups are hydroxyl, carboxyl, or a combination thereof;  
 (iii) one or more diol residues wherein at least 20 mole %, based on the total diol residues, is a poly(ethylene glycol) having a structure  
 H—(OCH2—CH 2 ) n —OH  
  wherein n is an integer in the range of 2 to about 500;  
 (iv) 0 to about 25 mole %, based on the total repeating units, of residues of a branching monomer having 3 or more functional groups wherein said functional groups are hydroxyl, carboxyl, or a combination thereof;  
 
 (B) optionally, a water-dispersible polymer blended with said sulfopolyester; and  
 (C) optionally, a water-nondispersible polymer blended with said sulfopolyester to form a blend with the proviso that said blend is an immiscible blend.  
   II. heating said polymer composition to a temperature above its flow point; and    III. melt spinning filaments.    
     
     
         24 . A process for water-dispersible, nonwoven fabric comprising 
 I. providing a water-dispersible polymer composition comprising 
 (A) a sulfopolyester having a glass transistion temperature (Tg) of at least 25° C., said sulfopolyester comprising: 
 (i) residues of one or more dicarboxylic acids;  
 (ii) about 4 to about 40 mole %, based on the total repeating units, of residues of at least one sulfomonomer having 2 functional groups and one or more metal sulfonate groups attached to an aromatic or cycloaliphatic ring wherein said functional groups are hydroxyl, carboxyl, or a combination thereof;  
 (iii) one or more diol residues wherein at least 20 mole %, based on the total diol residues, is a poly(ethylene glycol) having a structure  
 H—(OCH2—CH2) n —OH  
  wherein n is an integer in the range of 2 to about 500;  
 (iv) 0 to about 25 mole %, based on the total repeating units, of residues of a branching monomer having 3 or more functional groups wherein said functional groups are hydroxyl, carboxyl, or a combination thereof;  
 
 (B) optionally, a water-dispersible polymer blended with said sulfopolyester; and  
 (C) optionally, a water-nondispersible polymer blended with said sulfopolyester to form a blend with the proviso that said blend is an immiscible blend.  
   II. heating said polymer composition to a temperature above its flow point;    III. melt spinning filaments; and    IV. overlapping and collecting said filaments of Step III to form a nonwoven web.