Absorbent laminate structure

Claim 2

A layered absorbent structure of substantially uniform overall density, said structure having an upper surface and a lower surface, said structure comprising: (a) n webs of fibrous materials, n being an integer of two or more, said webs being layered such that there is an uppermost web, a lowermost web, n-2 intermediate webs, and n-1 interfaces of two opposed adjacent contacting surfaces of adjacent webs, each of said interfaces having a surface area; and (b) discretely spaced absorbent particles forming a discontinuous layer at one or more of said interfaces; said opposed adjacent contacting surfaces, at each said interface where said particles are present, being substantially entirely frangibly bonded to one another by fiber entanglement at substantially all points of contact between said contacting surfaces without creating discrete areas of densification in said webs of fibrous materials, said frangible bonding of said opposed adjacent contacting surfaces by fiber entanglement being strong enough to keep said discretely spaced particles immobilized at said interface(s) while said layered absorbent structure remains dry, yet weak enough to separate and allow substantially unconstrained expansion of said absorbent particles when said layered absorbent structure is wetted by an aqueous fluid.

Claim 3

The structure of claim 1 wherein said discretely spaced absorbent particles are substantially evenly distributed over said surface area of each said interface where said particles are present.

Claim 4

The structure of claim 2 wherein said absorbent particles are superabsorbent polymer particles which are substantially dry.

Claim 5

The structure of claim 3 wherein each of said fibrous webs exhibits a substantially uniform wicking characteristic across its surface, whereby if said structure is subsequently wetted by an aqueous fluid, each of said fibrous webs rapidly wicks said fluid in a substantially uniform manner across its surface to said discretely spaced absorbent particles, which particles absorb said fluid, swell and become substantially saturated in a substantially unconstrained manner.

Claim 6

The structure of claim 4 wherein said absorbent particles cover less than 90% of said surface area of each of said interfaces when they become substantially saturated.

Claim 7

The structure of claim 4 wherein said opposed adjacent surfaces of said adjacent webs, at each said interface where particles are present, are substantially entirely in contact over substantially all of said surface area of said interface except where said absorbent particles are present between said opposed adjacent surfaces and wherein overcoming said frangible bonding between said opposed adjacent surfaces of said adjacent webs by peeling involves at least a degree of sliding of one of said adjacent surfaces across the other.

Claim 8

A layered absorbent structure of substantially uniform overall density, said structure having an upper surface and a lower surface, said structure comprising: (a) n webs of fibrous materials, n being an integer of two or more, each of said webs having two substantially parallel surfaces, said webs being layered such that there is an uppermost web, a lowermost web, n-2 intermediate webs, and n-1 interfaces of two opposed adjacent contacting surfaces of adjacent webs, each of said interfaces having a surface area; each of said webs having multiple z-direction protrusions in one or both of its surfaces, each said protrusion having a corresponding z-direction concavity in the other surface of said web; where at each said interface, each z-direction protrusion of an adjacent surface intermeshes with a concavity of its opposed adjacent surface; and (b) discretely spaced absorbent particles forming a discontinuous layer at one or more of said interfaces; said opposed adjacent contacting surfaces, at each said interface where said particles are present, being substantially entirely frangibly bonded to one another by fiber entanglement at substantially all points of contact between said contacting surfaces without creating discrete areas of densification in said webs of fibrous material, said frangible bonding of said opposed adjacent contacting surfaces by fiber entanglement being strong enough to keep said discretely spaced particles immobilized at said interface(s) while said layered absorbent structure remains dry, yet weak enough to separate and allow substantially unconstrained expansion of said absorbent particles when said layered absorbent structure is wetted by an aqueous fluid.

Claim 9

A layered absorbent structure of substantially uniform overall density, said structure having an upper surface and a lower surface, said structure comprising: (a) n webs of fibrous materials, n being an integer of two or more, each of said webs having two substantially parallel surfaces, said webs being layered such that there is an uppermost web, a lowermost web, n-2 intermediate webs, and n-1 interfaces of two opposed adjacent contacting surfaces of adjacent webs, each of said interfaces having a surface area; each of said webs having multiple z-direction protrusions in one or both of its surfaces, each said protrusion having a corresponding z-direction concavity in the other surface of said web; where at each said interface, each z-direction protrusion of an adjacent surface intermeshes with a concavity of its opposed adjacent surface; and (b) discretely spaced absorbent particles forming a discontinuous layer at one or more of said interfaces; said opposed adjacent contacting surfaces, at each said interface where said particles are present, being substantially entirely frangibly bonded to one another by fiber entanglement at substantially all points of contact between said contacting surfaces without creating discrete areas of densification in said webs of fibrous material, said frangible bonding of said opposed adjacent contacting surfaces by fiber entanglement being strong enough to keep said discretely spaced particles immobilized at said interface(s) while said layered absorbent structure remains dry, yet weak enough to separate and allow substantially unconstrained expansion of said absorbent particles when said layered absorbent structure is wetted by an aqueous fluid.

Claim 10

The structure of claim 7 wherein said opposed adjacent surfaces of said adjacent webs at said interface(s) where said particles are present are substantially entirely frangibly bonded by fiber entanglement between said contacting surfaces due to said intermeshing of said z-direction protrusions with said z-direction concavities.

Claim 11

The structure of claim 8 wherein said discretely spaced particles are substantially evenly distributed over said surface area of each said interface where said particles are present, and wherein said particles are immobilized within said structure substantially entirely by fiber entrapment.

Claim 12

The structure of claim 9 wherein said absorbent particles are superabsorbent polymer particles which are substantially dry.

Claim 13

The structure of claim 10 wherein said opposed adjacent surfaces of said adjacent webs at each said interface where particles are present are substantially entirely in contact over substantially all of said surface area of said interface except where said absorbent particles are present between said opposed adjacent surfaces and wherein overcoming said frangible bonding between said opposed adjacent surfaces of said adjacent webs by peeling involves at least a degree of sliding of one of said adjacent surfaces across the other.

Claim 14

The structure of claim 10 wherein said particles cover no more than 50% of said surface area of each of said interfaces.

Claim 15

The structure of claim 10 wherein about 90% (by weight) or more of said particles have an average diameter of from about 0.05 mm to about 1.0 mm.

Claim 16

The structure of claim 10 wherein one or both of said surfaces of each said web has from about 10 to about 50 protrusions per square centimeter.

Claim 17

The structure of claim 10 wherein each of said fibrous webs exhibits a substantially uniform wicking characteristic across its surface, whereby if said structure is subsequently wetted by an aqueous fluid, each of said fibrous webs rapidly wicks said fluid in a substantially uniform manner across its surface to said discretely spaced absorbent particles, which particles absorb said fluid, swell and become substantially saturated in a substantially unconstrained manner.

Claim 18

The structure of claim 15 wherein said absorbent particles cover less than 100% of said surface area of each of said interfaces when they become substantially saturated.

Claim 19

The structure of claim 16 wherein said particles have a water absorption capacity of 30 times their dry weight or more.

Claim 20

The structure of claim 16 wherein said superabsorbent polymer comprises saponified starch-polyacrylonitrile graft copolymers, starch-polyacrylic acid graft copolymers, crosslinked/grafted cellulose, saponified vinyl acetate-acrylic acid copolymers, starch grafted polyvinyl acetate, acrylic acid polymers, or crosslinked polyethylene oxide, or mixtures thereof.

Claim 21

The structure of claim 10 wherein said webs are absorbent papers.

Claim 22

The structure of claim 14 wherein said webs are absorbent tissues.

Claim 23

The structure of claim 20 wherein each of said webs has a basis weight of from about 15 g/m 2 to about 40 g/m 2 .

Claim 24

The structure of claim 10 wherein said webs are absorbent tissues each having a basis weight of from about 10 g/m 2 to about 100 g/m 2 .

Claim 25

The structure of claim 10 wherein n is from 2 to about 12.

Claim 26

The structure of claim 20 wherein n is from 2 to about 12.

Claim 27

The structure of claim 21 wherein n is from 2 to about 5.

Claim 28

A disposable diaper structure comprising: (a) a fluid-permeable topsheet; (b) a substantially fluid impermeable backsheet; and (c) a layered absorbent structure of substantially uniform overall density, said structure having an upper surface and a lower surface, said structure comprising: (I) n webs of fibrous materials, n being an integer of two or more, each of said webs having two substantially parallel surfaces, said webs being layered such that there is an uppermost web, a lowermost web, n-2 intermediate webs, and n-1 interfaces of two opposed adjacent contacting surfaces of adjacent webs, each of said interfaces having a surface area; each of said webs having multiple z-direction protrusions in one or both of its surfaces, each said protrusion having a corresponding z-direction concavity in the other surface of said web; where at each said interface, each z-direction protrusion of an adjacent surface intermeshes with a concavity of its opposed adjacent surface; (II) discretely spaced absorbent particles forming a discontinuous layer at one or more of said interfaces, said opposed adjacent contacting surfaces, at each said interface where said particles are present, being substantially entirely frangibly bonded to one another by fiber entanglement at substantially all points of contact between said contacting surfaces without creating discrete areas of densification in said webs of fibrous material, said frangible bonding of said opposed adjacent contacting surfaces by fiber entanglement being strong enough to keep said discretely spaced particles immobilized at said interface(s) while said layered absorbent structure remains dry, yet weak enough to separate and allow substantially unconstrained expansion of said absorbent particles when said layered absorbent structure is wetted by an aqueous fluid; said layered absorbent structure being between said topsheet and said backsheet.

Claim 29

A disposable diaper structure comprising: (a) a fluid-permeable topsheet; (b) a substantially fluid impermeable backsheet; and (c) a layered absorbent structure of substantially uniform overall density, said structure having an upper surface and a lower surface, said structure comprising: (I) n webs of fibrous materials, n being an integer of two or more, each of said webs having two substantially parallel surfaces, said webs being layered such that there is an uppermost web, a lowermost web, n-2 intermediate webs, and n-1 interfaces of two opposed adjacent contacting surfaces of adjacent webs, each of said interfaces having a surface area; each of said webs having multiple z-direction protrusions in one or both of its surfaces, each said protrusion having a corresponding z-direction concavity in the other surface of said web; where at each said interface, each z-direction protrusion of an adjacent surface intermeshes with a concavity of its opposed adjacent surface; (II) discretely spaced absorbent particles forming a discontinuous layer at one or more of said interfaces, said opposed adjacent contacting surfaces, at each said interface where said particles are present, being substantially entirely frangibly bonded to one another by fiber entanglement at substantially all points of contact between said contacting surfaces without creating discrete areas of densification in said webs of fibrous material, said frangible bonding of said opposed adjacent contacting surfaces by fiber entanglement being strong enough to keep said discretely spaced particles immobilized at said interface(s) while said layered absorbent structure remains dry, yet weak enough to separate and allow substantially unconstrained expansion of said absorbent particles when said layered absorbent structure is wetted by an aqueous fluid; said layered absorbent structure being between said topsheet and said backsheet.

Claim 30

The disposable diaper structure of claim 26 wherein said absorbent particles are superabsorbent polymer particles.

Claim 31

The disposable diaper structure of claim 27 wherein said diaper structure also comprises: (d) one or more layers of absorbent paper between said layered absorbent structure and said topsheet, and between said layered absorbent structure and said backsheet.

Claim 32

The disposable diaper structure of claim 27 wherein said diaper structure also comprises: (d) an absorbent fibrous batt between said layered absorbent structure and said topsheet.

Claim 33

The disposable diaper structure of claim 27 wherein said diaper structure also comprises: (d) an absorbent fibrous batt between said layered absorbent structure and said backsheet.

Claim 34

The disposable diaper structure of claim 29 wherein the density of said fibrous batt is from about 0.05 g/cm 2 to about 0.35 g/cm 3 .

Claim 35

The disposable diaper structure of claim 30 wherein the density of said fibrous batt is from about 0.05 g/cm 2 to about 0.35 g/cm 3 .