Process for producing absorbent core structures

• US 20060021695A1
• Filed: 07/28/2005
• Published: 02/02/2006
• Est. Priority Date: 07/28/2004
• Status: Active Grant

• Current Assignee: The Procter & Gamble Company
• Original Assignee: The Procter & Gamble Company
• Inventors: Blessing, Horst, Rietz, Markus, Jackels, Hans-Adolf
• Granted Patent: US 7,744,713 B2
• Time in Patent Office: Days
• US Class Current: 156/196
• 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 13/15764 Transferring, feeding or handling devices; Drives
• CPC Class Codes: A61F 13/15804 Plant, e.g. involving several steps
• CPC Class Codes: A61F 13/5323 having absorbent material located in discrete regions, e.g. pockets
• CPC Class Codes: B05C 1/0804 the material being applied without contact with the roller
• CPC Class Codes: B05C 1/0808 Details thereof, e.g. surface characteristics
• CPC Class Codes: B05C 1/0817 characterised by means for removing partially liquid or other fluent material from the roller, e.g. scrapers coating roller co-operating with dosing rollers B05C1/0834
• CPC Class Codes: B05C 11/1039 Recovery of excess liquid or other fluent material; Controlling means therefor
• CPC Class Codes: B05C 19/04 the particulate material being projected, poured or allowed to flow onto the surface of the work B05C19/02 takes precedence; involving spraying or electrostatic projection B05B B05C19/005 takes precedence
• CPC Class Codes: Y10T 156/1002 with permanent bending or reshaping or surface deformation of self sustaining lamina
• CPC Class Codes: Y10T 156/1007 Running or continuous length work
• CPC Class Codes: Y10T 156/1023 Surface deformation only [e.g., embossing]
• CPC Class Codes: Y10T 156/1025 to form undulated to corrugated sheet and securing to base with parts of shaped areas out of contact

Abstract

The present invention is method for forming a sandwich structure having a pattern of particulate material enveloped between a carrier material and a cover material. The method allows accurate forming of pre-determined pattern at high production speed. Such a method is particularly useful in the manufacture of disposable absorbent articles, such as baby diapers.

Claims

1. A method for producing a sandwich structure comprising a pattern of particulate material, said method comprising the steps of:

a.) providing at least one essentially flat web material as carrier and/or cover material;

b.) providing an essentially endless support means for said carrier material having a support pattern;

c.) providing a carrier material holding means;

d.) positioning said carrier material over said support means, whereby said carrier material contacts said support pattern with its support surface and whereby the relative speed between carrier material and the contact surface of said carrier support means is essentially zero;

e.) providing a particulate material;

f.) pre-metering the amount of the particulate material;

g.) providing a sandwich fixation means;

h.) combining said cover material with said carrier material and said particulate material being sandwiched there between;

i.) supporting said carrier material only in the region of the support pattern of the support means;

j.) deforming said carrier material by said carrier holding means such that indentations are formed in the unsupported regions; and

k.) transferring said particulate material into said indentations of said carrier material, thereby forming a primary pattern of particulate material.

2. A method for producing a sandwich structure according to claim 1, wherein said carrier material is a non-woven material selected from the group consisting of SMS type and SMMS type.

3. A method for producing a sandwich structure according to claim 1, wherein said carrier material has a CD-extensibility or a MD-extensibility of more than about 20%.

4. A method for producing a sandwich structure according to claim 1, wherein said carrier material has a ratio of MD-extensibility to CD-extensibility at a given load of not more than one to two.

5. A method for producing a sandwich structure according to claim 1, wherein said cover material is a non-woven material.

6. A method for producing a sandwich structure according to claim 1, wherein said particulate material is a bulk material.

7. A method for producing a sandwich structure according to claim 1, wherein said carrier support means is a rotatable drum, preferably having an outer cylinder shell.

8. A method for producing a sandwich structure according to claim 1, wherein said carrier holdings means comprises vacuum air suction.

9. A method for producing a sandwich structure according to claim 1, wherein said carrier support pattern comprises support pins.

10. A method for producing a sandwich structure according to claim 9, wherein said carrier support pins have a distance of more than 5 mm from each neighboring support pin.

11. A method for producing a sandwich structure according to claim 10, wherein said carrier support pins have a distance of not more than 30 mm from each neighboring support pin.

12. A method for producing a sandwich structure according claim 9, wherein said support pins have outwardly extending surface of at least about 0.8 mm².

13. A method for producing a sandwich structure according to claim 1, wherein said sandwich fixation means is selected from the group consisting of thermal-bonding, glue-bonding, and sprayed adhesive bonding.

14. A method for producing a sandwich structure according to claim 1, wherein said bonding region is at least 2%.

15. A method for producing a sandwich structure according to claim 14, wherein said bonding region is not more than 50% of the area of the pattern area.

16. A method for producing a sandwich structure according to claim 1, wherein said bonding region comprises essentially no particulate material, as assessed by the method for determining the absence of particles in the bonding area.

17. A method for producing a sandwich structure according to claim 1, wherein said carrier fixation means extends said carrier material such that it deforms out of the original flat state forming an indentation.

18. A method for producing a sandwich structure according to claim 17, wherein said indentations have a volume of more than 30 mm³.

19. A method for producing a sandwich structure according to claim 17, wherein the particulate material fills more than 5% of the volume of said indentations.

20. A method for producing a sandwich structure according to claim 19, wherein the particulate material fills not more than 150% of the volume of said indentations.