Generally thin, flexible sanitary napkin with stiffened center

• US 6,231,556 B1
• Filed: 06/18/1996
• Issued: 05/15/2001
• Est. Priority Date: 10/29/1990
• Status: Expired due to Fees

• Current Assignee: The Procter & Gamble Company
• Original Assignee: The Procter & Gamble Company
• Inventors: Osborn, Thomas Ward III
• Primary Examiner(s): Dawson, Glenn K.
• Assistant Examiner(s): KIDWELL, MICHELE M
• Application Number:
  US08/665,595
• Time in Patent Office: 1,792 Days
• Field of Search: 604/358, 604/378, 604/379, 604/380, 604/382, 604/385.1, 604/387, 604/385.101
• US Class Current: 604/385.08
• CPC Class Codes: A61F 13/15203 Properties of the article, e.g. stiffness or absorbency chemical aspects A61L15/00
• CPC Class Codes: A61F 13/15707 Mechanical treatment, e.g. notching, twisting, compressing, shaping
• CPC Class Codes: A61F 13/4702 having a reinforcing member
• CPC Class Codes: A61F 13/47227 for interlabial use
• CPC Class Codes: A61F 13/47236 characterised by an unusual contour
• CPC Class Codes: A61F 13/47263 with activating means, e.g. elastic, heat or chemical activatable means
• CPC Class Codes: A61F 13/47272 with a longitudinal raised end, e.g. cup-shaped gluteal groove for edge leakage prevention A61F13/494
• CPC Class Codes: A61F 13/474 adjustable
• CPC Class Codes: A61F 13/476 characterised by encircling the crotch region of the undergarment
• CPC Class Codes: A61F 13/491 specially adapted for gender distinct urine discharge pattern
• CPC Class Codes: A61F 13/511 Topsheet, i.e. the permeable cover or layer facing the skin
• CPC Class Codes: A61F 13/514 Backsheet, i.e. the impermeable cover or layer furthest from the skin A61F13/15211, A61F13/15252 take precedence
• CPC Class Codes: A61F 13/51478 being a laminate, e.g. multi-layered or with several layers
• CPC Class Codes: A61F 13/5148 having an impervious inner layer and a cloth-like outer layer
• CPC Class Codes: A61F 13/515 characterised by the interconnection of the topsheet and the backsheet
• CPC Class Codes: A61F 13/533 having discontinuous areas of compression
• CPC Class Codes: A61F 13/53409 having a folded core
• CPC Class Codes: A61F 13/535 inhomogeneous in the plane of the pad, e.g. core absorbent layers being of different sizes A61F13/5323, A61F13/537 take precedence
• CPC Class Codes: A61F 13/53717 the layer having a promotional function on liquid propagation in the horizontal direction
• CPC Class Codes: A61F 13/5605 specially adapted for sanitary napkins or the like
• CPC Class Codes: A61F 13/58 : Adhesive tab fastener elements A61F13/5611, A61F13/5616, A61F13/66 take precedence
• CPC Class Codes: A61F 13/622 : Fabric strip fastener elements, e.g. hook and loop
• CPC Class Codes: A61F 13/64 : Straps, belts, ties or endless bands A61F13/5605, A61F13/5622, A61F13/66 take precedence
• CPC Class Codes: A61F 2013/15292 : Resistance, i.e. modulus or strength
• CPC Class Codes: A61F 2013/15325 : Stress relaxation or compression recovery
• CPC Class Codes: A61F 2013/15357 : Stiffness, e.g. Taber rigidity
• CPC Class Codes: A61F 2013/15365 : Dimensions
• CPC Class Codes: A61F 2013/15373 : Calliper, i.e. thickness
• CPC Class Codes: A61F 2013/15382 : Reduced thickness
• CPC Class Codes: A61F 2013/1539 : being expandable
• CPC Class Codes: A61F 2013/15406 : Basis weight
• CPC Class Codes: A61F 2013/15422 : Density
• CPC Class Codes: A61F 2013/4512 : folded in special shape during use A61F13/534, A61F13/551, A61F13/56, A61F13/15747 take precedence
• CPC Class Codes: A61F 2013/455 : having a "W" shape
• CPC Class Codes: A61F 2013/4562 : cup-shaped
• CPC Class Codes: A61F 2013/4708 : Panty-liner
• CPC Class Codes: A61F 2013/49023 : being textured, e.g. corrugated
• CPC Class Codes: A61F 2013/49031 : being elastic in longitudinal direction
• CPC Class Codes: A61F 2013/49044 : being stretchable non-elastic panels, A61F13/4902 takes precedence
• CPC Class Codes: A61F 2013/49046 : at the crotch
• CPC Class Codes: A61F 2013/49057 : being stretchable in both longitudinal and transversal direction
• CPC Class Codes: A61F 2013/49063 : the diaper having decoupled components
• CPC Class Codes: A61F 2013/49065 : being joined by a transverse line
• CPC Class Codes: A61F 2013/49066 : being joined by an area of low stiffness
• CPC Class Codes: A61F 2013/49074 : hourglass; dog bone-shaped
• CPC Class Codes: A61F 2013/4908 : concave
• CPC Class Codes: A61F 2013/5055 : Possibility of doubling or putting in new pieces
• CPC Class Codes: A61F 2013/51066 : for rendering the surface hydrophilic
• CPC Class Codes: A61F 2013/51092 : characterized by the dimensions
• CPC Class Codes: A61F 2013/51411 : being impervious to fluids but not for air or vapours
• CPC Class Codes: A61F 2013/51429 : being elastomeric or stretchable sheet
• CPC Class Codes: A61F 2013/51441 : being a fibrous material
• CPC Class Codes: A61F 2013/5147 : the outer layer being adhesive itself
• CPC Class Codes: A61F 2013/51472 : for reducing noise
• CPC Class Codes: A61F 2013/530007 : being made from pulp
• CPC Class Codes: A61F 2013/530051 : being made in cross-linked cellulosic fibres
• CPC Class Codes: A61F 2013/530058 : with specific method of producing wood pulp fibres
• CPC Class Codes: A61F 2013/530094 : with mechanical pulp
• CPC Class Codes: A61F 2013/530102 : with thermomechanical pulp
• CPC Class Codes: A61F 2013/530109 : with chemithermomechanical pulp
• CPC Class Codes: A61F 2013/530131 : being made in fibre but being not pulp
• CPC Class Codes: A61F 2013/530145 : being short
• CPC Class Codes: A61F 2013/530153 : being long
• CPC Class Codes: A61F 2013/53016 : having special shape
• CPC Class Codes: A61F 2013/530167 : being crimped
• CPC Class Codes: A61F 2013/530255 : being hydrophobic fibres
• CPC Class Codes: A61F 2013/530335 : being in peat moss
• CPC Class Codes: A61F 2013/530445 : by defining a target or acquisition or vulnerability zone
• CPC Class Codes: A61F 2013/530875 : having holes
• CPC Class Codes: A61F 2013/53445 : from several sheets
• CPC Class Codes: A61F 2013/53721 : with capillary means
• CPC Class Codes: A61F 2013/53916 : with epicyclical pattern
• CPC Class Codes: A61F 2013/5395 : with thermoplastic agent, i.e. softened by heat
• CPC Class Codes: A61F 2013/5688 : inclined at an oblique angle to the longitudinal axis
• CPC Class Codes: A61F 2013/582 : with one strip on one place
• CPC Class Codes: A61F 2013/586 : on lateral flaps
• CPC Class Codes: A61F 2013/8491 : including test methods
• CPC Class Codes: D01D 5/253 : with a non-circular cross section; Spinnerette packs therefor D01D5/38 takes precedence

Abstract

A generally thin, flexible sanitary napkin capable of absorbing medium to high menstrual flows, and having a stiffened center is provided. In one embodiment, the sanitary napkin has a longitudinal central region is disposed along the length of at least a portion of the longitudinal centerline, and longitudinal side regions are disposed outboard of the longitudinal central region. The longitudinal central region of the sanitary napkin has a flexure-resistance that is greater than that of the longitudinal side regions. The embodiment of the sanitary napkin described above easily forms around the curvature of the wearer'"'"'s labia majora by cupping and surrounding the exterior of the labia majora. The longitudinal central region of the sanitary napkin forms the bottom of a cup-like trough under the wearer'"'"'s labia majora, and the longitudinal side regions are sufficiently flexible that they are able to form the sides of the trough structure.

Claims

1. A sanitary napkin having a length, a width, a longitudinal centerline, a stiffened longitudinal central region disposed along the length of at least a portion of the longitudinal centerline, and longitudinal side regions outboard of the longitudinal central region, a flexure resistance as measured through said longitudinal side regions and a flexure resistance as measured through said stiffened longitudinal central region, said sanitary napkin comprising:

a liquid pervious topsheet;

a liquid impervious backsheet joined to said topsheet;

an absorbent core positioned between said topsheet and said backsheet;

wherein said stiffened longitudinal central region has a length that is less than one half the length of said sanitary napkin, said longitudinal side regions have absorbent capacity, and the flexure resistance of said sanitary napkin as measured through said longitudinal central region is greater than the flexure resistance of said sanitary napkin as measured through the longitudinal side regions, and said sanitary napkin has a caliper as measured through said longitudinal side regions of less than about 5 mm.

2. The sanitary napkin of claim 1 having a caliper as measured through said longitudinal side regions of less than or equal to about 3 mm.

3. The sanitary napkin of claim 2 wherein the width of said longitudinal central region is less than or equal to about 5 cm.

4. The sanitary napkin of claim 3 wherein the flexure resistance of said sanitary napkin as measured through said longitudinal central region is at least about 25% greater than the flexure resistance of said sanitary napkin as measured through said longitudinal side regions.

5. The sanitary napkin of claim 3 wherein the flexure resistance of said sanitary napkin as measured through said longitudinal central region is at least about 50% greater than the flexure resistance of said sanitary napkin as measured through said longitudinal side regions.

6. The sanitary napkin of claim 4 wherein the flexure resistance of said sanitary napkin measured through said longitudinal central region is less than or equal to about 700 grams force.

7. The sanitary napkin of claim 4 wherein the flexure resistance of said sanitary napkin measured through said longitudinal side regions is less than or equal to about 600 grams force.

8. The sanitary napkin of claim 4 wherein the stiffened longitudinal central region is comprised of components comprising at least:

said topsheet, backsheet, and absorbent core; and

said stiffened longitudinal central region is stiffer than the surrounding longitudinal side regions by being provided with a structure selected from the group consisting of;

(1) a longitudinal central region with an increased caliper;

(2) at least one of the components comprising the longitudinal central region being folded to create double, or more, thickness of the said at least one of said components;

(3) at least one of the components of the longitudinal central region comprising several layers;

(4) at least one of the components of the longitudinal central region comprising stiffer materials;

(5) at least one of the components of the longitudinal central region having a higher basis weight in the longitudinal central region;

or (6) one or more additional components in the longitudinal central region.

9. The sanitary napkin of claim 4 additionally comprising a stiffening material positioned between said topsheet and said backsheet and centered along said longitudinal centerline in said longitudinal central region.

10. The sanitary napkin of claim 4 additionally comprising a stiffening material positioned between said topsheet and said backsheet and centered along said longitudinal centerline in said longitudinal central region.

11. The sanitary napkin of claim 4 additionally comprising a stiffening material positioned on said backsheet and centered along said longitudinal centerline in said longitudinal central region.

12. The sanitary napkin of claim 4 wherein a 66.5 cm² sample cut from a portion of the sanitary napkin that would be centered under the vaginal orifice when the sanitary napkin is worn has a test capacity for absorbing sterile saline of at least about 8.0 grams of sterile saline when submerged in sterile saline for 10 minutes and said entire sanitary napkin has a total capacity of at least about 22.0 grams under the same conditions.

13. A sanitary napkin having a longitudinal centerline, a stiffened longtudinal central region disposed along the length of at least a portion of the longitudinal centerline, a transverse centerline, two longitudinal edges, two end edges, a first end region extending from one of said end edges toward said transverse centerline, a second end region extending from the other end edge toward said transverse centerline, and a central region between said first and second end regions, a flexure resistance as measured through said end regions and a flexure resistance as measured through said stiffened longitudinal central region, said sanitary napkin comprising:

a liquid pervious topsheet;

a liquid impervious backsheet joined to said topsheet;

an absorbent core positioned between said topsheet and said backsheet, said absorbent core having two longitudinal edges and a width defined by said longitudinal edges;

wherein said stiffened longitudinal central region has a transverse width greater than or equal to about 5 cm, said longitudinal side regions have absorbent capacity, and the flexure resistance of said sanitary napkin as measured through said central region is greater than the flexure resistance of said sanitary napkin as measured through said first and second end regions, and said sanitary napkin has a caliper as measured through said first and second end regions of less than about 5 mm.

14. The sanitary napkin of claim 13 having a caliper as measured through said first and second end regions of less than or equal to about 3 mm.

15. The sanitary napkin of claim 14 wherein said first and second end regions extend from the end edges of the sanitary napkin between about ⅛

and ⅓

of the length of said sanitary napkin toward the transverse centerline.

16. The sanitary napkin of claim 15 wherein the flexure resistance of said sanitary napkin as measured through said central region is at least about 25% greater than the flexure resistance of said sanitary napkin as measured through said first and second end regions.

17. The sanitary napkin of claim 15 wherein the flexure resistance of said sanitary napkin as measured through said central region is at least about 50% greater than the flexure resistance of said sanitary napkin as measured through said first and second end regions.

18. The sanitary napkin of claim 16 wherein the flexure resistance of said sanitary napkin as measured through said central region is less than or equal to about 700 grams force.

19. The sanitary napkin of claim 16 wherein the flexure resistance of said sanitary napkin as measured through said first and second end regions is less than or equal to about 600 grams force.