Layered, absorbent structure, an absorbent article comprising the structure, and a method for the manufacture thereof

• US 5,944,706 A
• Filed: 11/21/1996
• Issued: 08/31/1999
• Est. Priority Date: 12/31/1993
• Status: Expired due to Term

• Current Assignee: The Procter & Gamble Company
• Original Assignee: The Procter & Gamble Company
• Inventors: Carlucci, Giovanni, Palumbo, Gianfranco
• Primary Examiner(s): Yu, Mickey
• Assistant Examiner(s): Nguyen, Tram A.
• Application Number:
  US08/669,451
• Time in Patent Office: 1,013 Days
• Field of Search: 604/378, 604/358, 604/365-368, 604/370
• US Class Current: 604/368
• CPC Class Codes: A61F 13/15658 Forming continuous, e.g. composite, fibrous webs, e.g. involving the application of pulverulent material on parts thereof
• CPC Class Codes: A61F 13/539 characterised by the connection of the absorbent layers with each other or with the outer layers

Abstract

Disclosed is a thin, layered, absorbent structure comprising first and second layers of fibrous material and an intermediate layer comprising particles of a hydrogelling, absorbent material, in an amount exceeding 120 g/m², and particles of a thermoplastic, polymeric, organic material; the first and second fibrous layers extend beyond the intermediate layer laterally to form longitudinal edge portions. The two fibrous layers are bound together with the intermediate layer between them by the melting of the particles of thermoplastic, polymeric, organic material and by means of a continuous line of adhesive extending longitudinally on each longitudinal edge portion.

Claims

1. A layered, absorbent structure, wherein the structure comprises, in combination, first and second layers (1, 2) of fibrous material and an intermediate layer (5) comprising a hydrogelling, absorbent material (3), in an amount exceeding 120 g/m², distributed between the first and second fibrous layers (1, 2), at least one of the first and second layers (1, 2) being permeable to liquids, and the intermediate layer (5) also comprising a thermoplastic, polymeric, organic material (7), the intermediate layer (5) bonding the first and second fibrous layers (1, 2) together, with the intermediate layer (5) between them.

2. An absorbent structure according to claim 1, wherein the first and second layers (1, 2) of fibrous material extend beyond the intermediate layer (5) laterally forming longitudinal edge portions (8), and in that the first and second layers (1, 2) of fibrous material are bonded together along each of the edge portions (8) by means of a continuous line of adhesive (10).

3. An absorbent structure according to claim 1, wherein the first and second layers (1, 2) of fibrous material have a basis weight of between about 20 g/m² and about 150 g/m².

4. An absorbent structure according to claim 1, wherein the quantity of the hydrogelling, absorbent material (6) distributed between the first and second fibrous layers (1, 2) is up to about 600 g/m².

5. An absorbent structure according to claim 1, wherein the quantity of thermoplastic material (7) present is between about 12 g/m² and about 180 g/m².

6. An absorbent structure according to claim 1, wherein the thermoplastic material (7) is present in the form of finely divided material.

7. An absorbent structure according to claim 1, wherein the thermoplastic material (7) has a melt flow index (M.F.I.) of at least 25 g/10 min.

8. An absorbent structure according to claim 1, wherein the absorbent structure is disposed in a disposable absorbent article between an upper liquid-permeable layer (25) and a lower layer (28) which is impermeable to liquids.

9. An absorbent structure according to claim 1, wherein the absorbent structure is disposed in an absorbent sanitary article made according to a method comprising the following steps:

providing a first continuous layer (25) of a liquid-permeable, flexible sheet material;

providing a second continuous layer (28) of a flexible sheet material which is impermeable to liquids;

providing at least one generally rectangular portion of the absorbent structure; and

combining the first continuous layer (25), the second continuous layer (28) and the absorbent structure in a manner such that the absorbent structure is disposed and fixed between the first and second continuous layers (25,

     28).

10. A layered, absorbent structure, wherein the structure comprises, in combination, first and second layers (1, 2) of a fibrous material with a basic weight of between about 20 g/m² and about 150 g/m², as well as an intermediate layer (5) comprising particles of a hydrogelling, absorbent material of which a quantity of from in excess of about 120 g/m² up to about 600 g/m² is distributed between the first and second fibrous layers (1, 2), at least one of the first and second fibrous layers (1, 2) being permeable to liquids, the first and second fibrous layers (1, 2) extending beyond the intermediate layer (5) laterally to form longitudinal edge portions (8), the intermediate layer (5) comprising a mixture of hydrogelling, absorbent material (6) and a quantity of between about 12 g/m² and about 180 g/m² of a finely divided thermoplastic, polymeric, organic material (7), which has a melt flow index (M.F.I.) of at least 25 g/10 min. and is intended to bond at least the first and second fibrous layers (1, 2) together with the intermediate layer (5) between them, forming discrete, spaced-apart bond spots (9), the layered, absorbent structure also being wherein the layers of fibrous material (1, 2) are bonded together along each longitudinal edge portion (8) by means of a continuous line of adhesive (10).

11. An absorbent structure according to claim 10, wherein the structure is generally rectangular.

12. An absorbent structure according to claim 10, wherein the structure comprises more than two layers of fibrous material with an intermediate layer (5) between each pair of fibrous layers, the intermediate layer comprising a mixture of hydrogelling, absorbent material (6) and finely divided, thermoplastic material (7).

13. An absorbent structure according to claim 10, wherein the layers of fibrous material (1, 2) comprise dry-formed layers of short cellulose fibres.

14. An absorbent structure according to claim 10, wherein the layers of fibrous material (1, 2) are made of different materials.

15. An absorbent structure according to claim 13, wherein one of the fibrous layers (1, 2) is made of a mixture of cellulose fibres and bicomponent polyethylene/polypropylene fibres.

16. An absorbent structure according to claim 10, wherein the thermoplastic material (7) has a melt flow index of at least 40 g/10 min, preferably at least 60 g/10 min.

17. An absorbent structure according to claim 10, wherein the thermoplastic material (7) is in the form of solid hot melting particles.

18. An absorbent structure according to claim 10, wherein the thermoplastic material is polyethylene-based.

19. An absorbent structure according to claim 18, wherein the thermoplastic material is in the form of a quantity of between about 12 g/m² and about 180 g/m² of polyethylene particles with maximum dimensions of 400 microns.

20. An absorbent structure according to claim 18, wherein the thermoplastic material (7) is in the form of fibrils.

21. An absorbent structure according to claim 10, wherein the adhesion lines (10) comprise a hot melting adhesive.

22. An absorbent structure according to claim 10, wherein the structure thickness is no more than 4 mm.

23. An absorbent structure according to claim 22, wherein its thickness is no more than 3 mm.

24. An absorbent structure according to claim 10, wherein the hydrogelling, absorbent material has an absorption under a pressure of 5 kPa of at least 10 g/g.

25. An absorbent structure according to claim 24, wherein the said absorption is at least 12 g/g.

26. An absorbent structure according to claim 25, wherein the said absorption is at least 15 g/g.

27. An absorbent structure according to claim 26, wherein the said absorption is at least 17 g/g.

28. An absorbent structure according to claim 10, wherein the hydrogelling, absorbent material has a gel permeability under a pressure of 2 kPa of not more than 150 seconds.

29. An absorbent structure according to claim 28, wherein the permeability is not more than 100 seconds.

30. An absorbent structure according to claim 29, wherein the permeability is not more than 80 seconds.

31. An absorbent structure according to claim 10, wherein the absorbent structure is made by a method comprising the following steps:

providing the first layer (1) of fibrous material;

providing the second layer (2) of fibrous material of a width such that it can contact the first layer (1) along respective longitudinal edge portions (8);

distributing a mixture of particles of hydrogelling, absorbent material (6), in an amount exceeding 120 g/m², as well as the finely divided, thermoplastic material (7) on the first layer (1) of fibrous material, the mixture being distributed in a manner such that the longitudinal edge portions (8) of the first layer (1) are left free;

applying lines of adhesive (10) to the longitudinal edge portions (8) of the first layer (1); and

combining the first layer (1), the intermediate layer (5) and the second layer (2) in a layered structure by the application of heat and pressure to melt the thermoplastic material to a substantial extent, so as to form discrete, spaced-apart bond points (9) between the first layer (1) and the second layer (2), which have the intermediate layer (5) between them, with the lines of adhesive (10) bonding the first and second layers (1,

     2) together along the longitudinal edge portions.

32. An absorbent structure according to claim 31 wherein the lines of adhesive (10) are applied in the form of continuous lines.