Absorbent articles having nonwoven topsheets and backsheets having a nonwoven outer layer are known. For example, U.S. Pat. Nos. B1, 3,860,003 (Buell, Apr. 18, 1989) and 5,151,092 (Buell et al., Sep. 29, 1992) disclose disposable absorbent articles having a topsheet that may be formed from a nonwoven material, and U.S. Pat. No. 4,753,840 (Van Gompel, Jun. 28, 1988) teaches a coated fabric comprising a base nonwoven ply having a thermoplastic film bonded thereto.
Nonwovens for topsheet and backsheet applications should have certain properties suitable for the intended application, for example, in diapers. First, nonwovens to be used in absorbent articles should be soft and non-irritating to the wearer. It is particularly desirable to provide backsheet materials which are "clothlike," i.e., which are cool to the touch and drapeable. Second, such nonwovens should have sufficient strength for their intended application. Thus, the nonwoven should not split or tear during fabrication or use of the absorbent article. Finally, the nonwoven should have sufficient coverage or opacity for a given application. The strength and coverage of a nonwoven depend to a large extent on the basis weight of the nonwoven. Nonwovens used in disposable absorbent articles will typically have a basis weight ranging from about 15 gsy to about 30 gsy in order to provide the desired strength and coverage. Unfortunately, while strength and coverage may be increased by an increase in basis weight, the softness tends to decrease. Thus, it is a particular challenge to provide nonwovens having each of these properties such that they are suitable for use in absorbent articles.
One approach to improving the softness of a nonwoven material is described in U.S. Pat. No. 5,296,289 (Collins, Mar. 22, 1994). It is an object of U.S. Pat. No. 5,296,289 to provide a spun bonded nonwoven web which has been stretched to provide a soft "hand" and greater coverage with minimal sacrifices in strength as a result of stretching in the machine direction or the cross direction, although there is a substantial reduction in basis weight of the web commensurate with the amount of dimensional increases. The stretchable webs taught by Collins have spot bonds distributed in a "cornrow" bond pattern. The Collins patent discloses that stretching of certain prior art nonwoven webs will improve the hand somewhat, but with unacceptable losses in tensile strength and elongation characteristics.
While some of the problems of providing functional yet tactilely acceptable nonwoven materials, topsheets and backsheets have at least been partially ameliorated by the art, none has solved the problems in the manner or to the extent of the present invention.
It is an object of the present invention to provide a nonwoven which is soft yet which also has sufficient strength and coverage for use in disposable absorbent articles. It is an additional object of the present invention to provide disposable absorbent articles, and particularly backsheets of such articles, having a clothlike tactile perception.
USPTO Backgrounds
USPTO Backgrounds