Method for making extrusion coated perforated nonwoven web
A method for making an extrusion coated perforated nonwoven web. The method comprises the steps of extruding a molten polyethylene coating onto a nonwoven web, and aperturing the molten polyethylene coating through heat and pneumatic pressure differential to create microperforations therein at a density of between about 35 and about 120 perforations per linear inch. The resulting microperforated nonwoven web is then thermomechanically perforated by feeding it through perforating rolls, at least one of which has raised protuberances to create macroperforations that extend though at least the polyethylene coating. The macroperforations have a density of between about 6 and about 35 perforations per linear inch. The perforated nonwoven web is useful as a topsheet for absorbent articles.
1. A method for making an extrusion coated, perforated nonwoven web, comprising:
(a) extruding a molten polyethylene coating having a basis weight between about 7 and about 17 gsm onto a nonwoven web having a basis weight between about 9 and about 40 gsm;
(b) while aperturing said molten polyethylene coating through heat and pneumatic pressure differential to create raised conical microperforations therein at a density of between about 35 and about 120 perforations per linear inch to provide a microperforated nonwoven web; and then
(c) thermomechanically perforating said microperforated nonwoven web by feeding it through perforating rolls that contact the nonwoven web, at least one of said perforating rolls having raised protuberances to create macroperforations therein that extend through at least the polyethylene coating, said macroperforations having a density of between about 6 and about 35 perforations per linear inch, wherein said microperforations and said macroperforations are capable of absorbing and transporting liquid.
2. The method of claim 1 wherein the polyethylene coating has a basis weight between about 10 and about 15 gsm.
3. The method of claim 1 wherein the polyethylene coating comprises a co-extruded polymeric blend and inorganic filler particles.
4. The method of claim 1 wherein the nonwoven web comprises low density polyethylene.
5. The method of claim 1 wherein the microperforations have a density of between about 45 and about 80 perforations per linear inch.
6. The method of claim 1 wherein the macroperforations are elliptical shape and extend through both the polyethylene coating and the nonwoven web.
7. The method of claim 1 wherein the macroperforations have a density of between about 8 and about 25 perforations per linear inch.
8. The method of claim 1 wherein the nonwoven web is made of at least two layers and at least one layer contains shaped fibers to provide preferential fluid transport.
9. The method of claim 1 wherein the nonwoven web has additional texturing or macro-embossing in different areas to enhance the performance or the appearance of the web.