Air-laid web with high modulus fibers

Abstract

The present invention is directed to an air-laid composition comprising absorbent, binder, and synthetic fibers, wherein the synthetic fibers have a modulus greater than about 2 grams per denier, and a percent crimp of less than about 30%. The absorbent comprises about 40 to 80% of the weight of the composition. The binder comprises about 3-15% of the weight of the composition. The synthetic fibers comprise about 10-50% of the weight of the composition. The binder is selected from the class comprising conventional latex systems, hot melt adhesive, or binder fibers, or a mixture of these. The absorbent comprises natural absorbents or super absorbent polymer, or a combination of these. The natural absorbent materials are selected from the class consisting of wood pulp fluff, cotton, cotton linters, and regenerated cellulose fibers. The super absorbent polymer is selected from the class of agar, pectin, guar gum and synthetic hydrogel polymers. The synthetic fibers are selected from the class of polyolefins, such polyethylene, polypropylene and the like; polyesters such as polyethylene terephthalate and the like; polyamides such as nylon 6, nylon 6,6, and the like; acrylics; as well as mixtures and copolymers thereof. The synthetic fibers have an average length of from about 3-18 mm.

What is claimed is:  
     
         1 . An air-laid composition comprising: absorbent, binder, and synthetic fibers, said synthetic fibers having a modulus greater than about 2 gpd; and a percent crimp less than about 30%.  
     
     
         2 . The composition of  claim 1 , wherein said absorbent comprises natural absorbents or super absorbent polymer, or a combination of these.  
     
     
         3 . The composition of  claim 2 , wherein said natural absorbent materials are selected from the class consisting of wood pulp fluff, cotton, cotton linters, and regenerated cellulose fibers.  
     
     
         4 . The composition of  claim 2 , wherein the super absorbent polymer is selected from the class of agar, pectin, guar gum and synthetic hydrogel polymers.  
     
     
         5 . The composition of  claim 4 , wherein said synthetic hydrogel polymers is selected from the class of carboxymethyl cellulose, alkali metal salts of polyacrylic acid, polyacrylamides, polyvinyl alcohol, ethylene maleic anhydride copolymers, polyvinyl ethers, hydroxypropyl cellulose, polyvinyl morpholinone, polymers and copolymers of vinyl sulfonic acid, polyacrylates, polyacrylamides, polyvinyl pyridine, and mixtures of two or more of these.  
     
     
         6 . The composition of  claim 1 , wherein said absorbent comprises from about 40 to about 80% of the weight of said composition.  
     
     
         7 . The composition of  claim 1 , wherein said synthetic fibers are selected from the class of polyolefins, such polyethylene, polypropylene and the like; polyesters such as polyethylene terephthalate and the like; polyamides such as nylon 6, nylon 6,6, and the like; acrylics; as well as mixtures and copolymers thereof.  
     
     
         8 . The composition of  claim 1 , wherein said synthetic fibers comprise from about 10 to about 50% by weight of said composition.  
     
     
         9 . The composition of  claim 1 , wherein said synthetic fiber has a denier of between about 3 to about 15.  
     
     
         10 . The composition of  claim 1 , wherein said binder is selected from the class comprising conventional latex systems, hot melt adhesive, or binder fibers, or a mixture of these.  
     
     
         11 . The composition of  claim 10 , wherein said binder is binder fibers and comprises 3-15% by weight of said composition.  
     
     
         12 . The composition of  claim 10 , wherein said binder is a conventional latex system comprising styrene-butadiene copolymer, acrylate polymer, and polyvinyl acetate polymer, and mixtures of these.  
     
     
         13 . The composition of  claim 11 , wherein said binder fibers are bicomponent fibers selected from the class of polyethylene/polypropylene; polyethylene/polyester; polypropylene/polyester; copolyester/polyethylene terephthalate; and mixtures of these.  
     
     
         14 . The composition of  claim 1 , wherein said modulus is greater than about 2.5 gpd.  
     
     
         15 . The composition of  claim 1 , wherein said percent crimp is less than about 25%.  
     
     
         16 . The composition of  claim 1 , wherein said synthetic fibers have a denier in a range from about 3 to about 15.  
     
     
         17 . The composition of  claim 1 , wherein said synthetic fibers have an average length of from about 3-18 mm.  
     
     
         18 . The composition of  claim 1 , wherein said modulus is greater than about 3.0 gpd.  
     
     
         19 . A rigid air-laid web comprising: 10-50% by weight polyester fiber, 3-15% by weight binder fiber, and 40-80% by weight absorbent, said polyester fiber having a modulus greater than about 2 gpd and a percent crimp of less than about 30%.  
     
     
         20 . The web of  claim 19 , wherein said polyester fiber has a modulus greater than about 2.5 gpd and a percent crimp less than about 25%.  
     
     
         21 . A process of forming a rigid air-laid web comprising: blending 10-50% by weight polyester fiber, 3-15% by weight bicomponent fibers, and 40-80% by weight wood pulp together and subjecting them to a flowing air stream; heating said web until said bicomponent fibers become molten; and cooling said web until said web is rigid, wherein said polyester fiber has a modulus of greater than about 2 gpd, and a percent crimp of less than about 30%.