Claims
- 1. A method for producing a stretched moisture vapor permeable multi-ply film comprising the steps of:extruding a polymer comprising a filler having a particle size suitable for pore formation, said polymer suitable for use as a polymeric film; hot blowing the extruded film, forming a hot blown film bubble; collapsing said hot blown film bubble, forming a multi-ply film comprising a plurality of film plies; and stretching said plurality of film plies, forming a stretched multi-ply film having a plurality of micropores in each of said film plies, said micropores having an average pore size not greater than about 0.06 microns; wherein the stretched multi-ply film has a moisture vapor transmission rate of at least about 1200 grams/m2-24 hours and meets the barrier standards defined in ASTM F1670 and ASTM F1671.
- 2. A method in accordance with claim 1, wherein said filler comprises in a range of about 10% to about 50% by volume of said film.
- 3. A method in accordance with claim 2, wherein said filler comprises in a range of about 35% to about 40% by volume of said film.
- 4. A method in accordance with claim 1, wherein said micropores have an average pore size in a range of about 0.05 microns to about 0.06 microns.
- 5. A method in accordance with claim 1, wherein said filler comprises a plurality of CaCO3 particles.
- 6. A method in accordance with claim 1, wherein said particle size of said filler is in a range of about 0.5 microns to about 8.0 microns.
- 7. A method in accordance with claim 6, wherein said particle size of said filler is in a range of about 0.7 microns to about 1.0 microns.
- 8. A method in accordance with claim 1, wherein said stretching of said film is in a machine direction.
- 9. A method in accordance with claim 1, wherein said film is stretched at a stretch ratio in a range of about 3.5:1 to about 5.0:1.
- 10. A method in accordance with claim 1, wherein a total film gauge of said stretched film is about 0.8 mils.
- 11. A method in accordance with claim 1, wherein said stretched film has a WVTR in a range of about 1200 g/m2/24 hours to about 4500 g/m2/24 hours.
- 12. A method in accordance with claim 1, wherein said stretched film is bonded to a nonwoven web material layer, forming a nonwoven/film laminate.
- 13. A method in accordance with claim 12, wherein said nonwoven web material layer is comprises a spunbond web.
- 14. A method in accordance with claim 1, wherein said stretched film is bonded to two nonwoven web material layers, forming a nonwoven/film/nonwoven laminate.
- 15. A method in accordance with claim 14, wherein each of said nonwoven web material layers comprises a spunbond web.
- 16. A method in accordance with claim 1, wherein said polymer comprises linear low-density polyethylene (LLDPE).
- 17. A method in accordance with claim 1, wherein a basis weight of said stretched film is in a range of about 0.6 osy to about 1.0 osy.
- 18. A method for producing a stretched moisture vapor permeable multi-ply film comprising the steps of:extruding a polymer comprising a filler having a particle size suitable for pore formation, said polymer suitable for use as a non-elastic polymeric film; hot blowing the extruded film, forming a hot blown film bubble; collapsing said hot blown film bubble, forming a multi-ply film comprising a plurality of film plies; and stretching said plurality of film plies, forming a plurality of micropores in each of said film plies, said micropores having an average pore size not greater than about 0.06 microns; wherein the stretched multi-ply film has a moisture vapor transmission rate of at least about 1200 grams/m2-24 hours and meets the barrier standards defined in ASTM F1670 and ASTM F1671.
Parent Case Info
This application claims benefit of U.S. Provisional Application No. 60/069,946, filed Dec. 17, 1997.
US Referenced Citations (33)
Foreign Referenced Citations (4)
Number |
Date |
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197 01 244 |
Jul 1998 |
DE |
0 854 164 |
Dec 1997 |
EP |
04249132 |
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JP |
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WO |
Provisional Applications (1)
|
Number |
Date |
Country |
|
60/069946 |
Dec 1997 |
US |