Fibers including a crystalline polyolefin and a hydrocarbon tackifier resin, and process for making same

Abstract

Nonwoven fibrous webs including a multiplicity of (co)polymeric fibers made of a mixture including from about 50% w/w to about 99% w/w of at least one crystalline polyolefin (co)polymer, and from about 1% w/w to about 40% w/w of at least one hydrocarbon tackifier resin. A process for making the nonwoven fibrous webs includes heating the foregoing mixture to at least a Melting Temperature of the mixture to form a molten mixture, extruding this molten mixture through at least one orifice to form at least one filament, applying a gaseous stream to attenuate the at least one filament to form a plurality of discrete, discontinuous fibers, and cooling the plurality of discrete, discontinuous fibers to a temperature below the Melting Temperature and collecting the discrete discontinuous fibers as a nonwoven fibrous web. The nonwoven fibrous webs exhibit a Heat of Fusion measured using Differential Scanning Calorimetry of greater than 50 Joules/g.

What is claimed is: 
     
         1 . A nonwoven fibrous web, comprising:
 a plurality of (co)polymeric fibers comprising from about 50% w/w to about 99% w/w of at least one crystalline polyolefin (co)polymer, and from about 1% w/w to about 40% wiw of at least one hydrocarbon tackifier resin, wherein the nonwoven fibrous web exhibits a Heat of Fusion measured using Differential Scanning Calorimetry of greater than 50 Joules/g.   
     
     
         2 . The nonwoven fibrous web of  claim 1 , wherein the at least one crystalline polyolefin (co)polymer is selected from the group consisting of polyethylene, isotactic polypropylene, syndiotactic polypropylene, isotactic polybutylene, syndiotactic polybutylene, poly-4-methyl pentene and mixtures thereof. 
     
     
         3 . The nonwoven fibrous web of  claim 2 , wherein the at least one crystalline polyolefin (co)polymer exhibits a Heat of Fusion measured greater than 50 Joules/g. 
     
     
         4 . The nonwoven fibrous web of  claim 1 , wherein the at least one hydrocarbon tackifier resin is a saturated hydrocarbon. 
     
     
         5 . The nonwoven fibrous web of  claim 1 , wherein the at least one hydrocarbon tackifier resin is selected from the group consisting of C 5  piperylene derivatives, C 9  resin oil derivatives, and mixtures thereof. 
     
     
         6 . The nonwoven fibrous web of  claim 1 , wherein the at least one hydrocarbon tackifier resin makes up from 2% to 40% by weight of the (co)polymeric fibers. 
     
     
         7 . The.nonwoven fibrous web of  claim 6 , wherein the at least one hydrobarbon tackifier resin makes up from 5% to 30% by weight of the (co)polymeric fibers. 
     
     
         8 . The nonwoven fibrous web of  claim 7 , wherein the at least one hydrocarbon taekifier resin makes up from 7% to 20% by weight of the (co)polytheric fibers. 
     
     
         9 . The nonwoven fibrous web of  claim 1 , wherein the plurality of (co)polymeric fibers exhibit a mean Actual Fiber Diameter of from about 100 nanometers to about 1 micrometer, inclusive, as determined using Scanning Electron Microscopy. 
     
     
         10 . The nonwoven fibrous web of  claim 9 , wherein the plurality of (co)polymeric fibers exhibits a mean Effective Fiber Diameter of between about 1 micrometer to about 20 micrometers. 
     
     
         11 . The nonwoven fibrous web of  claim 1 , further comprising between 0 to about 30% of at least one plasticizer. 
     
     
         12 . The nonwoven fibrous web of  claim 11 , wherein the at least one plasticizer is selected from the group consisting of oligomers of C 5  to C 14  olefins, and mixtures thereof. 
     
     
         13 . The nonwoven fibrous web of  claim 1 , wherein the nonwoven fibrous web exhibits a Maximum Load in the Machine Direction of at least 5 Newtons as measured using the Tensile Strength Test. 
     
     
         14 . The nonwoven fibrous web of  claim 1 , wherein the nonwoven fibrous web-exhibits a Basis Weight of 1 gsm to 400 gsm. 
     
     
         15 . The nonwoven fibrous web of  claim 14 , wherein the nonwoven fibrous web exhibits a Basis Weight of 1 gsm to 50 gsm. 
     
     
         16 . A process for making a nonwoven fibrous web, comprising:
 a) heating a mixture of about 50% w/w to about 99% w/w of at least one crystalline polyolefin(co)polymer, and from about 1% w/w to about 40% w/w of at least one hydrocarbon tackifier resin to at least a Melting Temperature of the mixture to form a molten mixture;   b) extruding the molten mixture through at least one orifice to form at least one filament;   c) applying a gaseous stream to the at least one filament to attenuate the at least one filament to form a plurality of discrete, discontinuous fibers; and   d) cooling the plurality of discrete discontinuous fibers to temperature below the Melting Temperature of the molten mixture to form a nonwoven fibrous web, wherein at least one of the crystalline polyolefin(co)polymer or the nonwoven fibrous web exhibits a Heat of Fusion measured using Differential Scanning Calorimetry of greater than 50 Joules/g.   
     
     
         17 . The process of  claim 16 , wherein applying a gaseous stream to the at least one filament to attenuate the at least one filament to form a plurality of discrete, discontinuous fibers is accomplished using a process selected from the group consisting of melt-blowing, gas jet fibrillation, and combinations thereof. 
     
     
         18 . The process of  claim 16 , further comprising at least one of addition of a plurality of staple fibers to the plurality of melt-blown fibers, or addition of a plurality of particulates to the plurality of melt-blown fibers. 
     
     
         19 . The process of  claim 16 , further comprising collecting the plurality of discrete discontinuous fibers as the nonwoven fibrous web on a collector. 
     
     
         20 . The process of  claim 19 , further comprising processing the collected nonwoven fibrous web using a process selected from the group consisting of autogenous bonding, through-air bonding, electret charging, embossing, needle-punching, needle tacking, hydroentangling, or a combination thereof.