Diaper Structure With Enhanced Tactile Softness Attributes

Abstract

A diaper structure with enhanced softness attributes is disclosed. The diaper structure may include an innermost layer formed of a first nonwoven web, and an outermost layer formed of a second nonwoven web. The first and second nonwoven webs may have a combined basis weight of at least about 30 gsm. The ratio of the first web basis weight to the second web basis weight may range from 30/70 to 70/30. Each of the webs may have a preconversion density no greater than 65 kg/m 3 . Each of the webs may have a compression loft of at least 30%. Characteristics affecting pressure diffusion at tactile pressure points may be balanced within ranges between the first and second webs to provide similar tactile pressure diffusion characteristics for the inside and outside of the diaper.

1 . A disposable diaper, comprising a topsheet formed of a first nonwoven web, a backsheet formed at least in part of a second nonwoven web which forms the outermost layer of the diaper, and an absorbent core comprising particles of absorbent gelling material disposed between the topsheet and the outermost layer, wherein:
 the first nonwoven web and the second nonwoven web have a combined basis weight of at least 30 gsm;   the ratio of the basis weight of the first nonwoven web to the basis weight of the second nonwoven web is from 30/70 to 70/30; and either   each of the first nonwoven web and the second nonwoven web has a pre-conversion density of no greater than 65 kg/m 3 , or   each of the first nonwoven web and the second nonwoven web has a compression loft of at least 30%.   
     
     
         2 . The disposable diaper of  claim 1  wherein the first nonwoven web and the second nonwoven web are spunbond or spunbond-meltblown-spunbond (SMS) nonwoven webs. 
     
     
         3 . The disposable diaper of  claim 2  wherein at least one of the first nonwoven web or the second nonwoven web has a macroscopic surface approximating a plane, a machine direction and a cross direction perpendicular to the machine direction, and the at least one or both of the first nonwoven web or the second nonwoven web is formed predominately of polymeric fibers and comprises a series of one or more consolidating bonds impressed on the surface, the one or more consolidating bonds having at least one bond shape; wherein the series is repeated to form a pattern of consolidating bonds; wherein the series is repeated in at least four rows extending predominately in the cross direction, and the series is repeated in at least four columns extending predominately in the machine direction; and wherein the bond shape has a perimeter with a greatest measurable length and a greatest measurable width, and the perimeter:
 has a convex portion; 
 has an aspect ratio of the greatest measurable length to the greatest measurable width of at least 2.5; and 
 is oriented such that a line intersecting the perimeter along which the greatest measurable length exists intersects an axis lying on the surface along the machine direction to form a smaller angle of between 1 degree and 40 degrees. 
 
     
     
         4 . The disposable diaper of  claim 1  wherein the first nonwoven web and the second nonwoven web each have an opacity greater than 40%. 
     
     
         5 . The disposable diaper of  claim 1  wherein the first nonwoven web forms at least 50 percent of the wearer-facing planar surface area of the diaper as defined and circumscribed by the outer profile of the diaper. 
     
     
         6 . The disposable diaper of  claim 1  wherein the second nonwoven web forms at least 50 percent of the outward—facing planar surface area of the diaper as defined and circumscribed by the outer profile of the diaper. 
     
     
         7 . The disposable diaper of  claim 1  wherein the first nonwoven web forms at least 50 percent of the wearer-facing planar surface area of the diaper as defined and circumscribed by the outer profile of the diaper; the second nonwoven web forms at least 50 percent of the outward-facing planar surface area of the diaper as defined and circumscribed by the outer profile of the diaper; and the first nonwoven web and the second nonwoven web are disposed in overlying/underlying positions across at least 50 percent of the wearer-facing planar surface area of the diaper as defined and circumscribed by the outer profile of the diaper. 
     
     
         8 . The disposable diaper of  claim 1  wherein at least one of the first nonwoven web or the second nonwoven web has a static coefficient of friction equal to or less than 0.4. 
     
     
         9 . The disposable diaper of  claim 1  wherein at least one of the first nonwoven web or the second nonwoven web has a kinetic coefficient of friction equal to or less than 0.35. 
     
     
         10 . The disposable diaper of  claim 8  wherein the first nonwoven web and the second nonwoven web have respective static coefficients of friction that are within 30 percent of each other. 
     
     
         11 . The disposable diaper of  claim 9  wherein the first nonwoven web and the second nonwoven web have respective kinetic coefficients of friction that are within 30 percent of each other. 
     
     
         12 . The disposable diaper of  claim 1  wherein fibers forming at least one of the first nonwoven web or the second nonwoven web are crimped. 
     
     
         13 . The disposable diaper of  claim 12  wherein the crimped fibers are multicomponent fibers. 
     
     
         14 . The disposable diaper of  claim 13  wherein the multicomponent fibers have at least two polymer components having differing properties and disposed in either side-by-side configuration or eccentric core/sheath configuration. 
     
     
         15 . The disposable diaper of  claim 14  wherein each of the at least two polymer components comprise polypropylene. 
     
     
         16 . The disposable diaper of  claim 14  wherein at least one of the at least two polymer components comprises polyethylene. 
     
     
         17 . The disposable diaper of  claim 1  wherein the first nonwoven web and the second nonwoven web have a combined basis weight no more than 75 gsm. 
     
     
         18 . The disposable diaper of  claim 7  wherein at least a portion of the absorbent core is disposed between and the first nonwoven web and the second nonwoven web where the first nonwoven web and the second nonwoven web are disposed in said overlying/underlying positions, and said portion of the absorbent core is substantially cellulose-free. 
     
     
         19 . The disposable diaper of any  claim 1  wherein at least one of the ratios of:
 pre-conversion density of the of the first nonwoven web to pre-conversion density of the second nonwoven web, and 
 compression loft of the first nonwoven web to compression loft of the second non woven web, 
 
       is between 30/70 to 70/30. 
     
     
         20 . A disposable diaper, comprising a innermost layer formed of a first nonwoven web, an outermost layer formed at least in part of a second nonwoven web, and a plurality of spaced-apart elastomeric strands disposed between the first nonwoven web and the second nonwoven web, wherein:
 the first nonwoven web and the second nonwoven web have a combined basis weight of at least 30 gsm;   the ratio of the basis weight of the first nonwoven web to the basis weight of the second nonwoven web is from 30/70 to 70/30; and either   each of the first nonwoven web and the second nonwoven web has a pre-conversion (as it comes off the supply roll) density of no greater than 65 kg/m 3 , or   each of the first nonwoven web and the second nonwoven web has a compression loft at least 30%.