Fabric softener dryer sheet substrate

Abstract

A nonwoven fabric substrate for a clothes dryer fabric softener sheet is formed from substantially continuous filaments having a denier in the range of 2 to 12 denier per filament. The filaments include matrix filaments formed of polyester homopolymer and binder filaments formed of a polyester copolymer. A multiplicity of bonds exist throughout the fabric at locations where the binder filaments contact other filaments. These bonds integrate the fabric into a coherent nonwoven fabric with a grab tensile strength of at least 6 pounds per inch in the machine direction and at least 3.5 pounds per inch in the cross direction. The fabric has a basis weight of no more than 0.50 ounce per square yard and a thickness from about 0.180 mm to about 0.200 mm.

1 . A nonwoven fabric substrate for a clothes dryer fabric softener sheet, said nonwoven fabric substrate being formed from substantially continuous filaments having a denier within the range of 2 to 12 denier per filament, said filaments including matrix filaments formed of polyester homopolymer and binder filaments formed a polyester copolymer, and a multiplicity of bonds throughout the fabric at locations where the binder filaments contact other filaments, said bonds integrating the filaments into a coherent nonwoven fabric with a grab tensile strength of at least 6 pounds per inch in the machine direction and 3.5 pounds per inch in the cross-direction, said fabric having a basis weight of no more than 0.50 ounces per square yard and a thickness of from about 0.1 80mm to about 0.200 mm.  
     
     
         2 . The nonwoven fabric substrate of  claim 1 , wherein the grab tensile strength is at least 7 pounds per inch in the machine direction and at least 4.5 pounds per inch in the cross direction.  
     
     
         3 . The nonwoven fabric substrate of  claim 2 , wherein the thickness is from about 0.190 mm to about 0.195 mm.  
     
     
         4 . The nonwoven fabric substrate of  claim 1 , wherein the nonwoven fabric basis weight is 0.48 ounce per square yard.  
     
     
         5 . The nonwoven fabric substrate of  claim 1 , wherein the filaments have a denier per filament of 5 to 7.  
     
     
         6 . The nonwoven fabric substrate of  claim 1 , wherein the filament have a trilobal cross-section.  
     
     
         7 . The nonwoven fabric substrate of  claim 1 , in which the fabric is formed from 80% to 95% by weight polyethylene terephthalate homopolymer matrix filaments and 5% to 20% by weight polyethylene isophthalate copolymer binder filaments.  
     
     
         8 . A nonwoven fabric substrate for a clothes dryer fabric softener sheet, said nonwoven fabric substrate being formed from substantially continuous filaments having a trilobal cross-section and a denier within the range of 5 to 7 denier per filament, said filaments including 80% to 95% by weight polyethylene terephthalate homopolymer matrix filaments and 5% to 20% by weight polyethylene isophthalate copolymer binder filaments, and a multiplicity of bonds throughout the fabric at locations where the binder filaments contact other filaments, said bonds integrating the filaments into a coherent nonwoven fabric with a grab tensile strength of at least 7 pounds per inch in the machine direction and 4.5 pounds per inch in the cross-direction, said fabric having a basis weight of from about 0.46 to 0.50 ounces per square yard and a thickness of from about 0.190mm to about 0.195 mm.  
     
     
         9 . A process for producing a nonwoven fabric substrate for a clothes dryer fabric softener sheet, said process comprising extruding substantially continuous filaments, drawing the filaments to a denier within the range of 2 to 12 denier per filament, randomly depositing the filaments on a collection surface for form a filamentary web with a basis weight of no more than 0.50 ounce per square yard, consolidating the web of filaments in a steam consolidator at a surface temperature of less than 100 degrees C to maintain a fabric thickness of from about 0.180 mm to about 0.200 mm, and directing the consolidated nonwoven web through a hot air bonder and forming a multiplicity of bonds throughout the fabric at locations, the bonds imparting to the nonwoven fabric a tensile strength of at least 6 pounds per inch in the machine direction and 3.5 pounds per inch in the cross-direction.  
     
     
         10 . A process according to  claim 9 , wherein the surface temperature of the steam consolidator drum is less than 95 degrees C.  
     
     
         11 . A process according to  claim 10 , wherein said step of consolidating the web of filaments in a steam consolidator includes operating the consolidator at a chest steam flow of less than 12,000 pounds per hour and a drum pressure less than 12 pounds per square inch.  
     
     
         12 . A process according to  claim 9 , wherein the step of extruding substantially continuous filaments comprises extruding a first plurality of polyethylene terephthalate homopolymer matrix filaments from a first set of spinneret orifices and extruding a second plurality of polyethylene isopolymer binder filaments from a second set of spinneret orifices, and wherein the step of forming a multiplicity of bonds comprises forming bonds through out the web at locations where the binder filaments contact other filaments.