Absorbent foam materials for aqueous body fluids and absorbent articles containing such materials

• US 5,260,345 A
• Filed: 08/12/1991
• Issued: 11/09/1993
• Est. Priority Date: 08/12/1991
• Status: Expired due to Term

• Current Assignee: The Procter & Gamble Company
• Original Assignee: The Procter & Gamble Company
• Inventors: Young, Gerald A., Stone, Keith J., Thompson, Hugh A., Dyer, John C., DesMarais, Thomas A., LaVon, Gary D.
• Primary Examiner(s): Lesmes, George F.
• Assistant Examiner(s): RAIMUND, CHRISTOPHER W
• Application Number:
  US07/743,839
• Time in Patent Office: 820 Days
• Field of Search: 521/148, 521/150, 428/316.6
• US Class Current: 521/148
• CPC Class Codes: A61F 13/15203 Properties of the article, e.g. stiffness or absorbency chemical aspects A61L15/00
• CPC Class Codes: A61F 13/49012 the elastic means being elastic panels
• CPC Class Codes: A61F 13/53 characterised by the absorbing medium A61F13/20 takes precedence
• CPC Class Codes: A61F 13/532 inhomogeneous in the plane of the pad
• 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 13/5622 specially adapted for diapers or the like
• CPC Class Codes: A61F 2013/1539 being expandable
• CPC Class Codes: A61F 2013/530036 being made in chemically-modified cellulosic material, e.g. Rayon
• CPC Class Codes: A61F 2013/530459 being curled
• CPC Class Codes: A61F 2013/530467 being twisted
• CPC Class Codes: A61F 2013/530474 being cross-linked
• CPC Class Codes: A61F 2013/530481 having superabsorbent materials, i.e. highly absorbent polymer gel materials
• CPC Class Codes: A61F 2013/530708 characterized by the absorbency properties
• CPC Class Codes: A61F 2013/530802 characterized by the foam or sponge other than superabsorbent A61F2013/530649 takes precedence
• CPC Class Codes: A61F 2013/53081 with special pore dimension or arrangement
• CPC Class Codes: A61F 2013/530817 being open cells
• CPC Class Codes: A61F 2013/530839 being hydrophilic
• CPC Class Codes: A61F 2013/530854 being collapsed or collapsible foam
• CPC Class Codes: A61L 15/425 Porous materials, e.g. foams or sponges
• CPC Class Codes: C08F 2/32 Polymerisation in water-in-oil emulsions
• CPC Class Codes: Y10S 521/905 : Hydrophilic or hydrophobic cellular product
• CPC Class Codes: Y10S 521/918 : Physical aftertreatment of a cellular product
• CPC Class Codes: Y10T 428/249981 : Plural void-containing components

Abstract

Disclosed are absorbent foam materials suitable for use as or in the absorbent cores of absorbent articles, such as diapers which absorb and retain aqueous body fluids. Such foam materials comprise hydrophilic, flexible open-celled structures which are preferably prepared by polymerizing high internal phase (HIPE) water-in-oil emulsions. Such foam materials have a pore volume of from about 12 to 100 mL/g, and a capillary suction specific surface area of from about 0.5 to 5.0 m² /g. These materials also exhibit 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 when the material is saturated at 37° C. to its free absorbent capacity with synthetic urine.

Claims

1. A collapsed polymeric foam material which, upon contact with aqueous body fluids, expands and absorbs said fluids, said polymeric foam material comprising, when dried, a hydrophilic, flexible, non-hydrolyzed structure of interconnected open cells, which structure has a capillary suction specific surface area of from about 0.5 to 5.0 m² /g;

and which structure further has incorporated therein from about 0.5% to 20% by weight of residual water-insoluble emulsifier and from about 0.1% to 7% by weight of a toxicologically acceptable hygroscopic, hydrated salt;

said structure further having,

A) in its collapsed state;

i) a water content of from about 4% to 15% by weight of polymeric foam material; and

ii) a dry basis density of from about 0.08 to 0.3 g/cm³, and

B) in its expanded state,

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

ii) a resistance to compression deflection such that a confining pressure of 5.1 kPa produces after 15 minutes of strain from about 5% to 95% compression of the structure when it is saturated at 37°

C. to its free absorbent capacity with synthetic urine having a surface tension of 65±

5 dynes/cm; and

iii) a dry basis density upon saturation to its free absorbent capacity in said synthetic urine which ranges from about 9% to 28% of its dry basis density in its collapsed state.