Composite nonwoven its use and method of manufacture

Abstract

The invention concerns a composite nonwoven formed from fibrous layers bonded together by entanglement of fibers of the layers, wherein the fibrous layers comprise first and second outer layers each comprising a mixture of hydrophobic and hydrophilic fibers, as well as an intermediate layer of hydrophobic fibers sandwiched between the first and the second outer layers, the weight ratio between the hydrophobic and hydrophilic fibers in the first and the second layers being 20:80 to 80:20. The invention also concerns the manufacture of the nonwoven, as well as its use, especially as a wet wipe.

1 . A composite nonwoven formed from fibrous layers bonded together by entanglement of fibers of the layers, characterized in that the fibrous layers comprise first and second outer layers each comprising a mixture of hydrophobic and hydrophilic fibers, as well as an intermediate layer of hydrophobic fibers sandwiched between the first and the second outer layers, the weight ratio between the hydrophobic and hydrophilic fibers in the first and the second layers being 20:80 to 80:20.  
     
     
         2 . A nonwoven according to  claim 1 , characterized in that the hydrophobic fibers are polyolefin fibers, such as polypropylene or polyethylene fibers.  
     
     
         3 . A nonwoven according to  claim 1  or  2 , characterized in that the hydrophilic fibers are selected from the group consisting of cellulose-based fibers, such as viscose, cotton or pulp fibers.  
     
     
         4 . A nonwoven according to  claim 1 , characterized in that the hydrophobic fibers in the first and second outer layers are the same as in the intermediate layer.  
     
     
         5 . A nonwoven according to  claim 1 , characterized in that the fibers are carded staple fibers.  
     
     
         6 . A nonwoven according to  claim 1 , characterized in that the nonwoven has an average pore volume distribution wherein at least 70% of the total pore volume is associated with pores having an effective radius of greater than 125 μm.  
     
     
         7 . A nonwoven according to  claim 1 , characterized in that the nonwoven has an average pore volume distribution wherein at least 30% of the total pore volume is associated with pores having an effective radius of greater than 150 μm.  
     
     
         8 . A nonwoven according to  claim 1 , characterized in that the weight ratio between the hydrophobic and hydrophilic fibers in the first and second outer layers is 30:70 to 70:30.  
     
     
         9 . A nonwoven according to  claim 1 , characterized in that in the first and the second outer layers, the hydrophobic fibers are polypropylene fibers and the hydrophilic fibers are viscose fibers, the hydrophobic fibers of the intermediate layer being polypropylene fibers.  
     
     
         10 . A nonwoven according to  claim 9 , characterized in that the first and second outer layer contain polypropylene and viscose fibers in a weight ratio of 50:50.  
     
     
         11 . A nonwoven according to  claim 1 , characterized in that the weight of the layers are 10-80 g/m 2 .  
     
     
         12 . A nonwoven according to  claim 1 , characterized in that the fibrous layers consist of a first and second outer layer, and an intermediate layer.  
     
     
         13 . A wiping article, especially a wet wipe, comprising a composite nonwoven substrate according to  claim 1 .  
     
     
         14 . The wiping article according to  claim 13  loaded with a wiping liquid, such as an aqueous solution, emulsion, dispersion or lotion.  
     
     
         15 . The wiping article according to  claim 14  wherein the amount of liquid in the article is 2-5 g of liquid per g of dry nonwoven substrate.  
     
     
         16 . Method of manufacturing a composite nonwoven comprising the steps of 
 forming a layered web comprising first and second outer layers each comprising a mixture of hydrophobic and hydrophilic fibers, and an intermediate layer of hydrophobic fibers sandwiched between the first and the second outer layers, whereby the ratio of hydrophobic to hydrophilic fibers is 20:80 to 80:20 in the first and second outer layers,    hydroentangling the layered web to bond the layers by entanglement of fibers, and    drying the hydroentangled web.    
     
     
         17 . The method according to  claim 16 , wherein the layered web is formed by providing a first and a second web each comprising a mixture of hydrophobic and hydrophilic fibers, as well as a third web of hydrophobic fibers, conveying the so formed webs to combine the third web in facing relationship with each of the first and the second web, to sandwich the third web between the first and the second webs.  
     
     
         18 . The method according to the  claim 17  wherein the first, second and third webs are carded webs made from staple fibers.  
     
     
         19 . The method according to any one of the  claims 16  to  18  comprising the further step of adding a liquid to the formed composite nonwoven, preferably in an amount of 2 to 5 g per g of composite nonwoven.