Thin-unit-wet absorbent foam materials for aqueous body fluids and process for making same
AssigneeThe Procter & Gamble Company
InventorsJohn C. Dyer, Thomas A. DesMarais, Gary D. LaVon, Keith J. Stone, Gregory W. Taylor, Gerald A. Young
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Abstract
Relatively thin, collapsed, i.e. unexpanded, polymeric foam materials that, upon contact with aqueous body fluids, expand and absorb such fluids, are disclosed. A process for consistently obtaining such relatively thin, collapsed polymeric foam materials by polymerizing a specific type of water-in-oil emulsion, commonly known as High Internal Phase Emulsions or "HIPE", is also disclosed.
Claims23
A collapsed polymeric foam material which, upon contact with aqueous body fluids, expands and absorbs said fluids, said polymeric foam material comprising a hydrophilic, flexible, nonionic polymeric foam structure of interconnected open cells, which foam structure has:
- A) a specific surface area per foam volume of at least about 0.025 m.sup.2 /cc;
- B) at least about 0.1% by weight of said polymeric foam material of a toxicologically acceptable hygroscopic, hydrated salt incorporated therein:
- C) in its collapsed state, an expansion pressure of about 30 kPa or less;
- and
- D) in its expanded state, a density when saturated at 88.degree. F. (31.1.degree. C.) to its free absorbent capacity with synthetic urine having a surface tension of 65.+-.5 dynes/cm of from about 10 to about 50% of its dry basis density in its collapsed state.
A diaper article useful for absorbing aqueous body fluids discharged by an incontinent individual and having a fluid discharge region, said diaper article comprising:
- I) a liquid-impervious backing sheet;
- II) a liquid-pervious topsheet;
- III) an absorbent core positioned between said backing sheet and said top sheet, said absorbent core comprising a collapsed polymeric foam material which, upon contact with aqueous body fluids, expands and absorbs said fluids, said polymeric foam material comprising a hydrophilic, flexible, nonionic polymeric foam structure of interconnected open cells, which foam structure has:
- A) a capillary suction specific surface area of from about 1.5 to about 6 m.sup.2 /g;
- B) from about 3 to about 6% by weight of said polymeric foam material of calcium chloride and from about 5 to about 12% by weight of said polymeric foam material of sorbitan laurate incorporated therein;
- C) in its collapsed state:
- (i) a residual water content of from about 5 to about 15% by weight of said polymeric foam material;
- (ii) a dry basis density of from about 0.1 to about 0.2 g/cm.sup.3 ;
- (iii) an expansion pressure of from about 7 to about 20 kPa;
- D) in its expanded state:
- (i) a pore volume of from about 25 to about 50 mL/g;
- (ii) a resistance to compression deflection of from about 5 to about 40%;
- (iii) a number average cell size of from about 5 to about 35 microns;
- (iv) a density when saturated at 88.degree. F. (31.1.degree. C.) to its free absorbent capacity with synthetic urine having a surface tension of 65.+-.5 dynes/cm of from about 10 to about 30% of its dry basis density in its collapsed state.
Dependencies are inferred from the claim text.