High internal phase emulsion foam having cellulose nanoparticles
Inventors
Rowan, Stuart J. • Feke, Donald L. • Karimkhani, Vahid • Manas-Zloczower, Ica • Zhao, Boran • Hubbard, Jr., Wade Monroe • Wingert, Maxwell Joseph • Merrigan, Steven Ray
Assignees
Case Western Reserve University • Procter and Gamble Co
Publication Number
US-12319804-B2
Publication Date
2025-06-03
Expiration Date
2037-03-21
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Abstract
A High Internal Phase Emulsion (HIPE) foam having cellulose nanoparticles.
Core Innovation
The invention relates to a High Internal Phase Emulsion (HIPE) foam containing cellulose nanoparticles. The HIPE foam is produced by polymerizing an emulsion made up of an oil phase—including a monomer, a cross-linking agent, an emulsifier, and cellulose nanoparticles—and an aqueous phase. The HIPE foam exhibits an open-cell structure, with at least 80% of its cells larger than 1 μm being in fluid communication with adjoining cells.
The primary problem addressed by this invention is that current HIPE formulations are difficult to process and often lack desirable physical or structural properties such as high compression modulus, without sacrificing other properties like wettability and overall foam stability. There is a need for HIPE foams with improved compression modulus and fluid uptake.
The inclusion of cellulose nanoparticles in either the oil or aqueous phase of the HIPE has been found to significantly increase the compression modulus—ranging from a 1.1 to 25 times increase compared to HIPE foams without cellulose nanoparticles. Surface-modified cellulose nanoparticles, especially those made more hydrophobic before incorporation, provide further enhancement of mechanical properties. The use of cellulose nanoparticles also leads to an increase in wettability, as shown by improved Washburn coefficients in fluid uptake measurements.
Claims Coverage
There are two independent claims, each detailing inventive features relating to HIPE foam compositions containing cellulose nanoparticles as used in absorbent cores of absorbent articles.
High internal phase emulsion foam for absorbent core with cellulose nanoparticles
An absorbent article comprises an absorbent core formed from a high internal phase emulsion (HIPE) foam produced by polymerizing a HIPE, where the HIPE consists of: - An oil phase containing: - A monomer that is a substantially water-insoluble monofunctional alkyl acrylate or alkyl methacrylate (20%–97% by weight of the oil phase) - A cross-linking agent - An emulsifier - Cellulose nanoparticles - An aqueous phase containing a water-soluble electrolyte The resulting foam is open-cell, with at least about 80% of cells ≥1 μm being in fluid communication with at least one adjoining cell. The HIPE has a water-to-oil ratio between 13:1 and 65:1.
Open-cell high internal phase emulsion foam absorbent core with cellulose nanoparticles
An absorbent article containing an absorbent core made of a high internal phase emulsion foam, formed by polymerizing a HIPE composed of: - An oil phase including: - A substantially water-insoluble monofunctional alkyl acrylate or alkyl methacrylate (20%–97% by weight) - A cross-linking agent - An emulsifier - Cellulose nanoparticles - An aqueous phase with a water-soluble electrolyte The foam is required to be open-cell.
The claims cover absorbent articles with absorbent cores made from open-cell HIPE foams containing cellulose nanoparticles, specified monomer types, and defined emulsion compositions, offering enhanced physical structure and performance properties.
Stated Advantages
HIPE foams with cellulose nanoparticles exhibit increased compression modulus—between 1.1 to 25 times greater compared to HIPE foams without cellulose nanoparticles.
The use of cellulose nanoparticles leads to increased wettability of the HIPE foam, as shown by higher Washburn coefficients for fluid uptake.
Surface-modified cellulose nanoparticles enable the creation of HIPE foam with further improved compression modulus.
The open-cell and highly porous structure of the HIPE foam allows for effective fluid absorption and transfer.
Documented Applications
The HIPE foams are used as absorbent core materials in absorbent articles such as feminine hygiene articles (pads, pantiliners, tampons), disposable diapers, incontinence articles (pads, adult diapers), homecare articles (wipes, pads, towels), and beauty care articles (pads, wipes, and skin care articles).
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