Chemically bonded nonwoven substrates

Abstract

The present invention relates to chemically bonded nonwoven substrates and to polyester binders for chemically bonding nonwoven fibers of a nonwoven substrate.

The invention claimed is: 
     
         1 . A chemically bonded nonwoven substrate comprising nonwoven fibers bonded by a binder comprising a polyester resin. 
     
     
         2 . The chemically bonded nonwoven substrate according to  claim 1 , wherein the polyester resin is at least partially bio-sourced, and is based on at least 50% by weight of bio-sourced components based on the total weight of the polyester resin. 
     
     
         3 . The chemically bonded nonwoven substrate according to  claim 1 , wherein the polyester resin is based on a fatty component. 
     
     
         4 . The chemically bonded nonwoven substrate according to  claim 1 , wherein the polyester resin has an oil length of from 5% to 40% by weight based on the total weight of the polyester resin. 
     
     
         5 . The chemically bonded nonwoven substrate according to  claim 1 , wherein the polyester resin is based on a rosin component. 
     
     
         6 . The chemically bonded nonwoven substrate according to  claim 5 , wherein the rosin component comprises a resin acid corresponding to one of the following formulae (I) and (II), or a derivative thereof: 
       
         
           
           
               
               
           
         
         wherein the hashed bonds may independently be selected from single C—C bonds and double C═C bonds. 
       
     
     
         7 . The chemically bonded nonwoven substrate according to  claim 1 , wherein the polyester resin is based on from 30% to 85% by weight of resin acid or derivative thereof based on the total weight of the polyester resin. 
     
     
         8 . The chemically bonded nonwoven substrate according to  claim 1 , wherein the polyester resin has an acid number of 2 to 15 mg KOH/g. 
     
     
         9 . The chemically bonded nonwoven substrate according to  claim 1 , wherein the polyester resin has a number-average molecular mass Mn, measured by GPC as polystyrene equivalents in THF, ranging from 1000 to 10 000 g/mol. 
     
     
         10 . The chemically bonded nonwoven substrate according to  claim 1 , wherein the polyester resin has a Tg, measured by DSC, ranging from −40° C. to 50° C.. 
     
     
         11 . The chemically bonded nonwoven substrate according to  claim 1 , wherein the binder further comprises at least one ethylenically unsaturated resin. 
     
     
         12 . The chemically bonded nonwoven substrate according to  claim 11 , wherein the ethylenically unsaturated resin is selected from a (meth)acrylic resin, a styrene-acrylic resin, a vinyl-acrylic resin, an ethylene-vinyl ester resin, a vinyl ester resin, a styrene-butadiene resin, and combinations thereof. 
     
     
         13 . The chemically bonded nonwoven substrate according to  claim 11 , wherein the ethylenically unsaturated resin comprises monomer units derived from the polymerization of fumaric acid, maleic acid, itaconic acid, aconitic acid, mesaconic acid, anhydrides thereof and mixtures thereof. 
     
     
         14 . The chemically bonded nonwoven substrate according to  claim 1 , wherein the weight ratio between the polyester resin and the ethylenically unsaturated resin is from 1:10 to 10:1. 
     
     
         15 . The chemically bonded nonwoven substrate according to  claim 1 , wherein the nonwoven fibers are selected from natural fibers, modified natural fibers, synthetic fibers, inorganic fibers and mixtures thereof. 
     
     
         16 . The chemically bonded nonwoven substrate according to  claim 1 , wherein the chemically bonded nonwoven substrate is selected from abrasives and sheets for scouring, agricultural coverings, agricultural seed strips, apparel linings, automobile headliners, automobile upholstery, bed linen, bibs, blinds/curtains, cheese wraps, civil engineering fabrics, civil engineering geotextiles, coffee filters, cosmetic removers and applicators, covering and separation material, detergent pouches/fabric softener sheets, diapers, envelopes, filters, flooring, garment bags, household cleaning wipes, house wraps, hygiene products, insulation, labels, laundry aids, laundry bags, medical nonwovens, mops, personal wipes, reusable bags, roofing undercoverings and products, table linen, tags, tea and coffee bags, toilet paper, upholstery, vacuum cleaning bags, wallcoverings, wipes. 
     
     
         17 . A method for chemically bonding fibers of a nonwoven substrate comprising:
 i) contacting a binder comprising a polyester resin as defined in  claim 1  with a web of nonwoven fibers;   ii) curing the binder, thereby bonding the nonwoven fibers together to form a chemically bonded nonwoven substrate.   
     
     
         18 . The method according to  claim 17 , wherein the binder is in the form of an aqueous emulsion of the polyester resin. 
     
     
         19 . (canceled) 
     
     
         20 . The chemically bonded nonwoven substrate according to  claim 6 , wherein the resin acid is selected from the group consisting of abietic acid, pimaric acid, levopimaric acid, hydroabietic acid, dehydryoabietic acid, palustric acid, neoabietic acid, isopimaric acid, sandaracopimaric acid, derivatives thereof and mixtures thereof.