High loft nonwoven having balanced properties and a method of making same

Abstract

The present invention relates to process for making a light-weight, high loft nonwoven fabric. The process adds a drafter to a conventional nonwoven process in order to increase the production rate. Additionally, the invented process improves the quality of the manufactured fabric by increasing the tensile strength in the machine direction, providing balanced strength in the machine and cross directions, and enhancing resiliency. The process blends polyester fiber with a low melt fiber or low melt bicomponent fiber to form a web. The web is optionally carded and cross lapped before being drafted. Thereafter, the web is heated in an oven having sufficient heat to melt the low melt fiber then cooled to set the properties.

What is claimed is:  
     
         1 . A process for making a high-loft nonwoven fabric, comprising the steps of providing natural and/or synthetic fiber; providing a binder; providing a drafter; and drafting said fiber.  
     
     
         2 . The fabric making process according to  claim 1  wherein said synthetic fiber is selected from the class of polyester, polyamide, polyolefin, polyacrylic, cellulose acetate, melamine, rayon, mixtures of these, or copolymers of these.  
     
     
         3 . The fabric making process according to  claim 1  wherein said natural fiber is selected from the class of cotton, wool, flax, kenaf, hemp, silk, jute, asbestos, ramie, or mixtures of these.  
     
     
         4 . The fabric making process according to  claim 1  wherein said drafter includes rollers and said rollers are vertically spaced a distance from each other.  
     
     
         5 . The fabric making process according to  claim 4  wherein said vertically spaced distance between said rollers is in the range between 0 to about 40 mm.  
     
     
         6 . The fabric making process according to  claim 1  wherein the weight of the fabric is no more than 2.0 oz/ft 2 .  
     
     
         7 . The fabric making process according to  claim 6  wherein the weight of the fabric is in the range of 0.25 oz/ft 2  to 1.8 oz/ft 2 .  
     
     
         8 . The fabric making process according to  claim 1  wherein said fabric has a tensile strength in a machine direction that is at least 50 percent of the tensile strength in a cross direction.  
     
     
         9 . The fabric making process according to  claim 1  further including the step of mixing said natural and/or synthetic fiber and said binder.  
     
     
         10 . The fabric making process according to  claim 9 , wherein said binder is a low melt fiber or bicomponent fiber.  
     
     
         11 . The fabric making process according to  claim 10 , wherein said low melt binder comprises no more than about 30 percent by weight, of the fabric.  
     
     
         12 . The fabric making process according to  claim 11 , wherein said low melt binder comprises about 10 percent by weight of the fabric.  
     
     
         13 . The fabric making process according to  claim 9 , further including the steps of mixing said natural and/or synthetic fiber and said binder to form a web; cross lapping said web; and heating said web to a temperature sufficient to melt said binder.  
     
     
         14 . The fabric making process according to  claim 13 , wherein the step of cross lapping provides between 2 to 10 layers.  
     
     
         15 . A process of making high loft, nonwoven material, comprising the steps of: 
 providing natural and/or synthetic fibers;    providing low melt binder fibers, wherein the binder fibers comprises low melt fibers or bicomponent fibers;    mixing said low melt fibers and said natural and/or synthetic fibers to form a web;    cross lapping the web;    drafting the web with a drafter;    heating the drafted web to a temperature sufficient to melt the low melt binder fibers; and    cooling the web, whereby the nonwoven material is formed.    
     
     
         16 . The process of  claim 15 , further including the step of attenuating the web with the drafter.  
     
     
         17 . The process of  claim 15 , wherein the drafter comprising a plurality of zones, wherein each zone includes rollers, and wherein said rollers in each subsequent zone rotate at the same or greater rpm than the rollers in a previous zone.  
     
     
         18 . The process of  claim 15 , wherein the nonwoven material has a weight that is no more than 2.0 oz/ft 2  and has a tensile strength in a machine direction that is at least 50 percent of the tensile strength in a cross direction.  
     
     
         19 . A high loft nonwoven fabric prepared by a process comprising the steps of: 
 providing natural and/or synthetic fibers;    providing a binder;    cross lapping the fibers;    drafting the fibers with a drafter;    heating the fibers to a temperature sufficient to melt the binder; and cooling the fibers.    
     
     
         20 . The nonwoven fabric according to  claim 19  wherein said fabric has a weight in the range of 0.25 oz/ft 2  to 1.8 oz/ft 2 , and tensile strength in the machine direction that is at least 50 percent of the tensile strength in the cross direction.  
     
     
         21 . A nonwoven high loft batt, comprising: natural and/or synthetic fibers and a low melt binder wherein the loft recovery is at least 90% and the tensile strength in the MD and CD is within 50% of one another.  
     
     
         22 . The high loft batt of  claim 21 , wherein the tensile strength is within 30% of one another.  
     
     
         23 . The high loft batt of  claim 21 , wherein the tensile strength in the MD is higher than in the CD.  
     
     
         24 . The high loft batt of  claim 21 , wherein said synthetic fiber is selected from the class of polyester, polyamide, polyolefin, polyacrylic, cellulose acetate, melamine, rayon, mixtures of these, or copolymers of these.  
     
     
         25 . The high loft batt of  claim 21 , wherein said natural fiber is selected form the class of cotton, wool, flax, kenaf, hemp, silk, jute, asbestos, ramie, or mixtures of these.  
     
     
         26 . The high loft batt of  claim 21 , wherein the low melt binder can be a low melt fiber, a bicomponent fiber, or a latex resin.  
     
     
         27 . The high loft batt of  claim 26 , wherein said low melt fiber is polyolefin fiber.  
     
     
         28 . The high loft batt of  claim 26 , wherein said bicomponent fiber has a polyolefin low melt portion and a polyester high melt portion.  
     
     
         29 . The high loft batt of  claim 21 , wherein said synthetic fiber is polyester fiber.  
     
     
         30 . The high loft batt of  claim 29 , wherein said polyester fiber has different deniers per filament.  
     
     
         31 . The high loft batt of  claim 21 , wherein said batt has a weight of less than about 2 oz./sq ft.  
     
     
         32 . The high loft batt of  claim 21 , wherein said batt is comprised of 2-10 layers.