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Methods to Improve Blood Absorption of Superabsorbent Materials

IP.com Disclosure Number: IPCOM000028897D
Publication Date: 2004-Jun-07
Document File: 5 page(s) / 137K

Publishing Venue

The IP.com Prior Art Database

Related People

Jason English: AUTHOR [+4]

Related Documents

US 5,354,290: PATENT [+3]

Abstract

Superabsorbents have a broad range of applications in the personal and health care industries, due to their ability to absorb bodily fluids. However, their blood absorption ability is greatly hindered due to the complex physical and rheological properties of the fluid. As a result, significant research and development continues in an effort to improve the blood absorption. Here we investigate the effect of freeze-drying of superabsorbent on blood absorbency. In particular, we show that heat curing of freeze-dried superabsorbents leads to potentially useful changes in material properties.

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Methods to Improve Blood Absorption of Superabsorbent Materials

Jason English, Jian Qin, Alice Romans-Hess, and Cindy Phillips Kimberly-Clark Corporation

Neenah, Wisconsin

Superabsorbents have a broad range of applications in the personal and health care industries, due to their ability to absorb bodily fluids. However, their blood absorption ability is greatly hindered due to the complex physical and rheological properties of the fluid. As a result, significant research and development continues in an effort to improve the blood absorption. A variety of techniques have been proposed to improve blood absorption of superabsorbents. One example, where the superabsorbent is freeze-dried to increase blood absorption, is described in US Pat. No. 5,354,290, issued October 11, 1994, to J. Gross. Freeze-drying involves swelling (expanding) a superabsorbent in water, then removing the water in a frozen state which allows the superabsorbent to remain in an open state. This dramatically increases the internal pore volume, which is believed to enhance blood absorbency. Other principles of freeze-drying are given in US Pat. No. 6,706,944, "Absorbent Materials Having Improved Absorbent Properties," issued March 16, 2004 to Qin et al. and US Pat. No. 6,261,679, "Fibrous Absorbent Material and Methods of Making the Same," issued July 17, 2001 to Chen et al. We investigated the effect of freeze-drying of superabsorbent on blood absorbency. The blood absorbency was measured by weighing 0.04 grams of the superabsorbent onto a 50 mm diameter, 160 mesh screen with acrylic walls and spread as evenly as possible. Four samples are evaluated at once. Each screen is submerged in a dish containing 20 ml of 35% hematocrit swine blood available from Cocalico Biologicals, Inc., and allowed to soak for 30 minutes. After soaking, the screen is placed into a plastic container fitted to its diameter and placed into a centrifuge. Centrifugation was done at 1250 rpm in a Sorvall RT 6000D centrifuge (Kendro Laboratory Products, Asheville, North Carolina) for three minutes. The acrylic ring and mesh screen containing the superabsorbent particles were then removed from the centrifuge and weighed. Our findings indicate that a high volume of internal micropores created by the freeze- drying technology does not necessarily render higher blood absorbency of the corresponding freeze-dried superabsorbent. Table 1 lists blood absorbency changes upon freeze-drying of three commercial superabsorbents, Favor® SXM 9394, Favor 835 and Favor SXM 880, all available from Degussa Superabsorber, Greensboro, North Carolina.

Absorbency Change

SXM 9394 0 20.3 g/g 80 28.2 g/g + 38.9%

    835 0 21.1 g/g 77 20.0 g/g - 5.2% SXM 880 0 19.1 g/g 77 23.2 g/g + 21.5% Note: Swell Ratio means a weight ratio of water to superabsorbent.

Table 1. Blood absorbency Results of Freeze-Dried Superabsorbents.

Non-Freeze-Dried SAP Freeze-Dried SAP

Superabsorbent

(SAP) Swell

Ratio

  Blood Absorbency

  Blood Absorbency...