초록 ▼

An economical method is disclosed for modifying the physical characteristics of a nonwoven fibrous web which involves passing the web between at least one pair of interengaged rolls to incrementally stretch the web, and then withdrawing the incrementally stretched web from between the rolls under te

An economical method is disclosed for modifying the physical characteristics of a nonwoven fibrous web which involves passing the web between at least one pair of interengaged rolls to incrementally stretch the web, and then withdrawing the incrementally stretched web from between the rolls under tension. A web modified according to the disclosed method has advantageous elongation, extensibility and strength properties, as well as other desirable characteristics. In another aspect, a method is disclosed for forming a composite material by combining a modified nonwoven web with a polymeric film, or an elastic member, which may be liquid impervious yet breathable. In yet other aspect, a method is disclosed for forming a composite material by combining a modified web with a polymeric film which is rendered liquid-impervious yet breathable while the method is performed. The modified nonwoven webs and composite materials made according to the disclosed methods may be advantageously employed in absorbent articles such as disposable diapers.

대표청구항 ▼

1. A method for modifying a pre-formed, nonwoven fibrous web, said method comprising the steps of:a. feeding in a web movement direction to a pair of opposed, interengaged forming rolls a substantially untensioned, nonwoven fibrous web having an initial width, an initial thickness, an initial basis

1. A method for modifying a pre-formed, nonwoven fibrous web, said method comprising the steps of:a. feeding in a web movement direction to a pair of opposed, interengaged forming rolls a substantially untensioned, nonwoven fibrous web having an initial width, an initial thickness, an initial basis weight, an initial low-elongation cross-web extensibility expressed as an initial load to achieve 10% cross-web elongation, an initial intermediate-elongation cross-web extensibility expressed as an initial load to achieve 30% cross-web elongation, an initial cross-web strength, and an initial elongation capability; b. gripping the web between the interengaged forming rolls at a nip defined by the forming rolls, wherein each forming roll includes a plurality of axially spaced, circumferentially extending, alternating radial teeth and intervening grooves, and wherein the teeth of one roll are opposite from and extend into the grooves of the opposed roll; c. modifying the nonwoven web by subjecting the nonwoven web to incremental lateral stretching as the web passes between the interengaged forming rolls and as the rolls rotate in opposite directions, to incrementally stretch the web in a cross-web direction that is substantially perpendicular to the web movement direction and withdrawing the web from between the interengaged forming rolls by applying to the web a tensile withdrawal force that extends in the web movement direction, wherein the resulting modified web has a load to achieve 10% elongation of from about 5% to about 100% of the initial load to achieve 10% elongation, a load to achieve 30% elongation of from about 5% to about 100% of the initial load to achieve 30% elongation, a cross-web strength of from about 10% to about 80% of the initial cross-web strength, and a cross-web elongation capability of from about 105% to about 200% of the initial cross-web elongation capability.