Elastic materials and articles therefrom
AssigneeThe Dow Chemical Company
InventorsTodd J. Obijeski, Georgia M. Huff, Rexford A. Maugans, Osborne K. McKinney
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Abstract
Elastic materials, particularly films, strips, coatings, ribbons and sheets made from at least one substantially linear ethylene polymer are disclosed which can be fabricated on conventional polyolefin extrusion equipment. They can be used to produce elastic composite structures that are stretchable and have recycle compatibility between elastic and non-elastic components. The novel materials have at least about 80% recovery at 100% strain and are especially useful in making fabricated composite articles (e.g., disposable diapers).
Claims15
An elastic material having a percent recovery of at least about 80 percent and a thickness of less than about 22 mils comprising at least one homogeneously branched substantially linear ethylene polymer characterized as having:
- a) a melt flow ratio, I.sub.10 /I.sub.2, .gtoreq.5.63,
- b) a molecular weight distribution, M.sub.w /M.sub.n, defined by the equation:
- M.sub.w /M.sub.n .ltoreq.(I.sub.10 /I.sub.2)-4.63,
- c) a critical shear rate at onset of surface melt fracture of at least 50 percent greater than the critical shear rate at the onset of surface melt fracture of a linear ethylene polymer having about the same I.sub.2 and M.sub.w /M.sub.n, and
- d) a density less than about 0.89 g/cm.sup.3,
- wherein the elastic material is selected from the group consisting of films, strips, coatings, tapes, webs, ribbons, bands and sheets.
An elastic composite material comprising at least one elastic material having a percent recovery of at least about 80 percent and a thickness of less than about 22 mils, wherein the elastic material comprises at least one homogeneously branched substantially linear ethylene polymer characterized as having:
- a) a melt flow ratio, I.sub.10 /I.sub.2, .gtoreq.5.63,
- b) a molecular weight distribution, M.sub.w /M.sub.n, defined by the equation:
- M.sub.w /M.sub.n .ltoreq.(I.sub.10 /I.sub.2)-4.63,
- c) a critical shear rate at onset of surface melt fracture of at least 50 percent greater than the critical shear rate at the onset of surface melt fracture of a linear ethylene polymer having about the same I.sub.2 and M.sub.w /M.sub.n, and
- d) a density less than about 0.89 g/cm.sup.3,
- wherein the elastic material is selected from the group consisting of films, strips, coatings, tapes, webs, ribbons, bands and sheets.
A fabricated composite article comprising at least one elastic material having a percent recovery of at least about 80 percent and a thickness of less than about 22 mils, wherein the elastic material comprises at least one homogeneously branched substantially linear ethylene polymer characterized as having:
- a) a melt flow ratio, I.sub.10 /I.sub.2, .gtoreq.5.63,
- b) a molecular weight distribution, M.sub.w /M.sub.n, defined by the equation:
- M.sub.w /M.sub.n .ltoreq.(I.sub.10 /I.sub.2)-4.63,
- c) a critical shear rate at onset of surface melt fracture of at least 50 percent greater than the critical shear rate at the onset of surface melt fracture of a linear ethylene polymer having about the same I.sub.2 and M.sub.w /M.sub.n, and
- d) a density less than about 0.89 g/cm.sup.3,
- wherein the elastic material is selected from the group consisting of films, strips, coatings, tapes, webs, ribbons, bands and sheets.
A fabricated composite article comprising at least one elastic composite material, wherein the elastic composite material comprises at least one elastic material having a percent recovery of at least about 80 percent and a thickness of less than about 22 mils, wherein the elastic material comprises at least one homogeneously branched substantially linear ethylene polymer characterized as having:
- a) a melt flow ratio, I.sub.10 /I.sub.2, .gtoreq.5.63,
- b) a molecular weight distribution, M.sub.w /M.sub.n, defined by the equation:
- M.sub.w /M.sub.n .ltoreq.(I.sub.10 /I.sub.2)-4.63,
- c) a critical shear rate at onset of surface melt fracture of at least 50 percent greater than the critical shear rate at the onset of surface melt fracture of a linear ethylene polymer having about the same I.sub.2 and M.sub.w /M.sub.n, and
- d) a density less than about 0.89 g/cm.sup.3,
- wherein the elastic material is selected from the group consisting of films, strips, coatings, tapes, webs, ribbons, bands and sheets.
An elastic material having a percent recovery of at least about 80 percent and a thickness of less than about 22 mils consisting essentially of a homogeneously branched substantially linear ethylene polymer characterized as having:
- a) a melt flow ratio, I.sub.10 /I.sub.2, .gtoreq.5.63,
- b) a molecular weight distribution, M.sub.w /M.sub.n, defined by the equation:
- M.sub.w /M.sub.n .ltoreq.(I.sub.10 /I.sub.2)-4.63,
- c) a critical shear rate at onset of surface melt fracture of at least 50 percent greater than the critical shear rate at the onset of surface melt fracture of a linear ethylene polymer having about the same I.sub.2 and M.sub.w /M.sub.n, and
- d) a density less than about 0.89 g/cm.sup.3,
- wherein the elastic material is selected from the group consisting of films, strips, coatings, tapes, webs, ribbons, bands and sheets.
Dependencies are inferred from the claim text.