Elastic nonwoven sheet
AssigneeInvista North America S.A R.L.
InventorKenneth Martin
Life of this patent
Estimating the term…
Abstract
This invention relates to stretchable nonwoven sheets prepared by substantially uniformly impregnating a necked nonwoven substrate or an easily extensible as-made nonwoven substrate with an elastomeric polymer by treatment with an elastomeric polymer solution. The nonwoven sheet is useful in the manufacture of diapers and other hygiene articles.
Claims19
A method for forming a stretchable nonwoven sheet comprising the steps of:
- providing a necked nonwoven substrate having a thickness, first and second outer surfaces, a machine direction and a cross-direction, the necked nonwoven substrate having an percent elongation of at least 30% in the cross-direction;
- substantially uniformly impregnating the necked nonwoven substrate with a solution comprising an elastomeric polymer dissolved in a solvent;
- and
- removing the solvent from the impregnated nonwoven substrate by wet coagulation to deposit the elastomeric polymer substantially uniformly throughout the thickness of the nonwoven substrate without forming a substantially continuous layer of elastomeric polymer on either of the first or second outer surfaces of the nonwoven substrate.
A method for forming a stretchable nonwoven sheet comprising the steps of:
- providing an easily extensible as-made nonwoven substrate having a thickness, first and second outer surfaces, a machine direction and a cross-direction, a percent elongation of at least 30% in the cross-direction, a basis weight between about 15 g/m2 and about 100 g/m2, a break tenacity greater than 500 g/in;
- substantially uniformly impregnating the easily extensible as-made nonwoven substrate with a solution comprising an elastomeric polymer dissolved in a solvent;
- and
- removing the solvent from the easily-extensible as-made nonwoven substrate by wet coagulation to deposit the elastomeric polymer substantially uniformly throughout the thickness of the nonwoven substrate without forming a substantially continuous layer of elastomeric polymer on either of the first or second outer surfaces of the nonwoven substrate.
A stretchable nonwoven sheet comprising a necked nonwoven substrate substantially uniformly impregnated with an elastomeric polymer, the stretchable nonwoven sheet having a ratio of third unload cycle force at 100% elongation to third load cycle force at 100% elongation, after the stretchable nonwoven sheet has been extended to 140% in the necked direction three times, of at least 0.3:1.
A stretchable nonwoven sheet comprising an easily extensible as-made nonwoven substrate substantially uniformly impregnated with an elastomeric polymer, the stretchable nonwoven sheet having a ratio of third unload cycle force at 30% elongation to third load cycle force at 30% elongation, after the stretchable nonwoven sheet has been extended to 50% in the cross-direction three times, of at least 0.15:1.
Dependencies are inferred from the claim text.