Nonwoven fabrics prepared using visbroken single-site catalyzed polypropylene
AssigneeKimberly-Clark Worldwide, Inc.
InventorsRobert Louis Pekrul, Peter Michailovich Kobylivker
Life of this patent
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Abstract
Nonwoven filaments having improved melt spinning process characteristics and end use properties are prepared using a visbroken single-site catalyzed propylene polymer. The propylene polymer has a first melt flow rate (MFR) before visbreaking and a second MFR after visbreaking, such that the ratio of the second MFR to the first MFR is about 1:1 to about 3:1. The nonwoven filaments exhibit less filament tension during spinning, and permit higher line speeds before breaking, than similar filaments prepared using a single-site catalyzed propylene polymer having the second MFR straight out of the reactor, and which has not been visbroken.
Claims34
A nonwoven fabric including a plurality of melt spun filaments;
- the melt spun filaments comprising a visbroken single-site catalyzed propylene polymer having a molecular weight distribution of less than about 3.0 before visbreaking, and a first lower MFR before visbreaking and a second higher MFR after visbreaking;
- the second MFR having a value which is about 1-3 times the value of the first MFR;
- wherein the visbreaking is accomplished using at least one of peroxide, heat, radiation, and shear.
A nonwoven fabric including a plurality of melt spun filaments having an average diameter up to about 75 microns;
- the melt spun filaments comprising a visbroken single-site catalyzed propylene polymer having a molecular weight distribution of less than about 3.0 before visbreaking, and a first lower MFR before visbreaking and a second higher MFR after visbreaking;
- the second MFR having a value which is about 1-3 times the value of the first MFR;
- wherein the visbreaking is accomplished using at least one of peroxide, heat, radiation, and shear.
A personal care product comprising a nonwoven fabric;
- the nonwoven fabric including a visbroken single-site catalyzed propylene polymer having a molecular weight distribution of less than about 3.0 before visbreaking, and a first lower MFR before visbreaking and a second higher MFR after visbreaking;
- the second MFR having a value which is about 1-3 times the value of the first MFR;
- wherein the visbreaking is accomplished using at least one of peroxide, heat, radiation, and shear.
A medical product comprising a nonwoven fabric;
- the nonwoven fabric including a visbroken single-site catalyzed propylene polymer having a molecular weight distribution of less than about 3.0 before visbreaking, and a first lower MFR before visbreaking and a second higher MFR after visbreaking;
- the second MFR having a value which is about 1-3times the value of the first MFR;
- wherein the visbreaking is accomplished using at least one of peroxide, heat, radiation, and shear.
Dependencies are inferred from the claim text.