High efficiency absorbent articles for incontinence management

Claims

What is claimed is:

1. An absorbent article useful for absorbing aqueous body fluids discharged by an incontinent individual, said absorbent article comprising

A) a backing sheet; and

B) an absorbent core positioned on said backing sheet, said absorbent core comprising

i) a fluid acquisition/distribution component positioned to receive discharged body fluids, said fluid acquisition/distribution component comprising a porous hydrophilic structure which exhibits an initial Fluid Acquisition Rate of at least about 2 mL of synthetic urine per second; and

ii) a fluid storage/redistribution component maintained in fluid communication with said fluid acquisition/distribution component, said storage/redistribution component comprising a polymeric foam material having a hydrophilic, flexible, open-celled structure which has a free absorbent capacity at 37.degree. C. of at least about 12 mL of synthetic urine per gram of dry foam material and which also has an absorbent capacity for said synthetic urine under a confining pressure of 5.1 kPa maintained for 15 minutes at 37.degree. C. which is at least about 5% of its free absorbent capacity.

2. An absorbent article according to claim 1 wherein said backing sheet is relatively liquid-impervious.

3. An absorbent article according to claim 1 wherein:

A) the absorbent structure of the fluid acquisition/distribution component exhibits an initial Fluid Acquisition Rate of at least about 6 mL of synthetic urine per second and further exhibits a 30-minute Vertical Wicking Height of at least about 4.5 cm; and

B) the foam-based absorbent structure of the fluid storage/redistribution component has a free absorbent capacity at 37.degree. C. of at least 20 mL of synthetic urine per gram of dry foam material and also has an absorbent capacity for said synthetic urine under a confining pressure of 5.1 kPa maintained for 15 minutes at 37.degree. C. which is at least about 20% of the free absorbent capacity of said foam material.

4. An absorbent article according to claim 1 wherein:

A) the fluid acquisition/distribution component of the absorbent core has an upper layer comprising a nonwoven fibrous structure having an average dry density of less than about 0.3 g/cm.sup.3 ; an average density upon saturation with synthetic urine of less than about 0.2 g/cm.sup.3 and an average basis weight of from about 0.001 to 0.10 g/cm.sup.2 ; and

B) the fluid storage/redistribution component of the absorbent core has a lower layer comprising a polymeric foam material having, at the point of its use as an absorbent,

i) a pore volume of from about 12 to 100 mL/g;

ii) a specific surface area of from about 0.5 to about 5.0 m.sup.2 /g as determined by capillary suction; and

iii) a resistance to compression deflection such that a confining pressure of 5.1 kPa produces after 15 minutes a strain of from about 5% to 95% compression of the structure when it is saturated at 37.degree. C. to its free absorbent capacity with synthetic urine.

5. An absorbent article according to claim 4 wherein:

A) the non-woven fibrous structure of the fluid acquisition/distribution layer has an average dry density of from about 0.02 to 0.2 g/cm.sup.3 ; an average density upon saturation with synthetic urine of from about 0.02 to 0.2 g/cm.sup.3 ; and an average basis weight of from about 0.01 to 0.08 g/cm.sup.2 ; and

B) the polymeric foam material of the fluid storage/redistribution layer has, at the point of its use as an absorbent,

i) a pore volume of from about 20 to 70 mL/g;

ii) a specific surface area of from about 0.75 to about 4.5 m.sup.2 /g as determined by capillary suction; and

iii) a resistance to compression deflection such that a confining pressure of 5.1 kPa produces after 15 minutes a strain of from about 5% to 75% compression of the structure when it is saturated at 37.degree. C. to its free absorbent capacity with synthetic urine.

6. An absorbent article according to claim 5 wherein the weight ratio of the fluid acquisition/distribution layer to the fluid storage/redistribution layer ranges from about 1:4 to about 5:1.

7. An absorbent article according to claim 4 wherein:

A) the upper fluid acquisition/distribution layer of the absorbent core comprises from about 50% to 100% by weight of chemically stiffened, twisted, curled cellulosic fibers and from 0% to about 50% by weight of a binding agent for said chemically stiffened, twisted, curled cellulosic fibers; and

B) the lower fluid storage/redistribution layer of the absorbent core comprises a polymeric foam structure which is hydrophilic to the extent that the structure exhibits an adhesion tension of from about 20 to 65 dynes/cm when absorbing synthetic urine and which is prepared by polymerizing a water-in-oil emulsion formed from

i) an oil phase comprising

a) from about 3% to 41% by weight of a substantially water-insoluble, monofunctional glassy monomer component;

b) from about 27% to 73% by weight of a substantially water-insoluble, monofunctional rubbery comonomer component;

c) from about 8% to 30% by weight of a substantially water-insoluble, polyfunctional cross-linking agent component, and

d) from about 2% to 33% by weight of an emulsifier component which is soluble in the oil phase and which is suitable for forming a stable water-in-oil emulsion; and

ii) a water phase comprising an aqueous solution containing from about 0.2% to 40% by weight of water-soluble electrolyte;

the weight ratio of said water phase to said oil phase forming said emulsion ranging from 20:1 to 70:1.

8. An absorbent article according to claim 7 wherein:

A) the fluid acquisition/distribution layer of the absorbent core comprises from about 75% to 100% by weight of chemically stiffened, twisted, curled cellulosic fibers and from 0% to about 25% by weight of a binding agent which comprises refined cellulosic fibers having a Canadian Standard Freeness of less than about 200; and

B) the fluid storage/redistribution layer of the absorbent core comprises a polymeric foam material having, at the point of its use as an absorbent,

i) a density of from about 0.01 to 0.08 g/cm.sup.3 on a dry weight basis;

ii) an average cell size ranging from about 5 to 100 mi