(12) United States Patent (10) Patent No.: US 8,134,042 B2 Song Et Al
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USOO8134042B2 (12) United States Patent (10) Patent No.: US 8,134,042 B2 Song et al. (45) Date of Patent: Mar. 13, 2012 (54) WETNESS SENSORS 4,704,116 A 11/1987 Enloe 4,705,513 A 11/1987 Sheldon et al. 4,725,462 A 2f1988 Kimura (75) Inventors: S5 s9. syll 'S S): 4,826,550 A 5/1989 Shimizu et al. arold U. 1 ppey, Brunswick, (US); 5,003, 178 A 3/1991 Livesay Jessica Sara Van Handel, Menasha, WI 5, 192,606 A 3, 1993 Proxmire et al. (US) 5,197,958 A 3, 1993 Howell 5,221,228 A 6/1993 Pedroia (73) Assignee: Kimberly-Clark Worldwide, Inc., 5,266,592 A 11/1993 Grub et al. Neenah, WI (US) 5,389,093 A 2, 1995 Howell s 5,399,219 A 3, 1995 Roessler et al. - 5,486,166 A 1/1996 Bishop et al. (*) Notice: Subject to any disclaimer, the term of this 5.490,846 A 2f1996 Ellis et al. patent is extended or adjusted under 35 5,540,796 A 7, 1996 Fries U.S.C. 154(b) by 839 days. 5,595,618 A 1, 1997 Fries 5,702,377 A 12/1997 Collier, IV et al. 21) Appl. No.: 11/956,657 5,931,823. A 8, 1999 Stokes et al. (21) App 9 (Continued) (22) Filed: Dec. 14, 2007 FOREIGN PATENT DOCUMENTS (65) Prior Publication Data EP 1424918 11, 2005 US 2009/0157025 A1 Jun. 18, 2009 (Continued) (51) Int. Cl. OTHER PUBLICATIONS A6DF 3/5 (2006.01) International Search Report from PCT/IB2008/053676–8 pages. (52) U.S. Cl. ....................................................... 604/361 (58) Field of Classification Search ................... 604/361 Primary Examiner — Lynne Anderson See application file for complete search history. (74) Attorney, Agent, or Firm — Dority & Manning, PA. (56) References Cited (57) ABSTRACT U.S. PATENT DOCUMENTS In accordance with one embodiment of the present disclosure a method for detecting the presence of urine is described. The 4,032,661 A 6, 1977 Rowsell et al. method includes providing a urine indicating sensor with a 4,121,011 A 10, 1978 Glover et al. - 4,136,163 A 1/1979 Watson et al. porous matrix, the matrix having a pH indicator non-diffu 4,192,311 A 3, 1980 Fellfold sively immobilized thereon, the pH indicator being capable of 4,230,688 A 10, 1980 Rowsell et al. a color transition when in contact with urine. Urine is con 2. A 1 } XN, et al tacted with the matrix of the sensor and the presence of urine 4,507,121--- A 3/1985 LeungaO ( a. 1S determined based on whether the pH indicator- undergoes a 4,642,250 A 2/1987 Spector color transition. 4,653,491 A 3, 1987 Okada et al. 4,681,576 A 7, 1987 Colon et al. 17 Claims, 2 Drawing Sheets O s /1 US 8,134,042 B2 Page 2 U.S. PATENT DOCUMENTS 7.306,764 B2 * 12/2007 Mody ............................. 422,58 2003/O125682 A1 7, 2003 Olson et al. 5,962.995 A 10/1999 Avnery 2003/0164136 A1 9, 2003 Klofta et al. 6,060,638 A 5, 2000 Paul et al. 6,150.002 A 1 1/2000 V 2004/0102750 A1 5/2004 Jameson k - W aOla 2005.0054255 A1 3, 2005 Morman et al. 6,270,783 B1 8, 2001 Slavtcheffet al. 6.407,492 B1 6, 2002 A. 1 2005/0059941 A1 3, 2005 Baldwin et al. W Vinery et al. 2005, 0137542 A1* 6/2005 Underhill et al. ............. 604.361 6,486,227 B2 11/2002 Nohr et al. 2006/0229577 A1* 10, 2006 Roe etal 604.361 6,617.488 B1* 9/2003 Springer et al. .............. 604.361 2007/015610.6 A1* 7, 2007 E?. cal 604.361 6,627,233 B1 9/2003 Wolfetal. Ola Call. 6,635,797 B2 10/2003 Olson et al. FOREIGN PATENT DOCUMENTS 6,642,427 B2 * 1 1/2003 Roe et al. ...................... 604.361 6,663,611 B2 12/2003 Blaney et al. WO93, 1971.6 A1 10, 1993 6,733,766 B2 5/2004 Gott et al. WO WO9516425 6, 1995 6,772,708 B2 * 8/2004 Klofta et al. .................. 116/206 WO WOOOOOO82 A1 1/2000 6,780,896 B2 8/2004 MacDonald et al. WO WOO112150 2, 2001 7,002,054 B2 * 2/2006 Allen et al. ................... 604.361 * cited by examiner U.S. Patent Mar. 13, 2012 Sheet 1 of 2 US 8,134,042 B2 20 26 1 28 22 FIG. U.S. Patent Mar. 13, 2012 Sheet 2 of 2 US 8,134,042 B2 O 118 /1 100 US 8,134,042 B2 1. 2 WETNESS SENSORS Repeat use of reference characters in the present specifi cation and drawings is intended to represent same or analo BACKGROUND gous features or elements of the disclosure. Disposable absorbent articles such as diapers, training DETAILED DESCRIPTION pants, incontinence pads, and the like are highly absorbent and efficiently pull moisture away from the wearer, reducing Reference now will be made in detail to various embodi skin irritation caused by prolonged wetness exposure. How ments of the disclosure, one or more examples of which are ever, because these articles are so absorbent, wearers may not set forth below. Each example is provided by way of expla realize they have urinated, particularly if they are inexperi 10 nation of the disclosure, not limitation of the disclosure. In fact, it will be apparent to those skilled in the art that various enced toddlers who may not recognize the meaning of body modifications and variations can be made in the present dis sensations associated with urination. Thus, the wearer may closure without departing from the scope or spirit of the not recognize their urination control failure or be aware the disclosure. For instance, features illustrated or described as article should be changed. Furthermore, parents or caregivers 15 part of one embodiment, can be used on another embodiment may not recognize that the absorbent article requires chang to yield a still further embodiment. Thus, it is intended that the ing. present disclosure covers such modifications and variations Visual mechanisms have also been employed to signal the as come within the scope of the appended claims and their presence of wetness in absorbent articles. There are a large equivalents. number of wetness sensing technologies that currently exist In general, the present disclosure is generally directed to including electronic-based wetness sensors, color-based wet sensors for determining the presence or absence of urine. The ness sensors, and enzyme-based wetness sensors. However, sensors can utilize non-diffusively immobilized pH indica Such conventional sensors are often complicated and costly. tors and/or thermochromic mixtures to accurately detect the In addition, the signals produced by Such sensors are often presence or absence of urine. only present for a short period of time. Additionally, conven 25 Non-diffusive immobilization of a pH indicator on a solid tional sensing technologies do not provide a back-up to con matrix can greatly extend the period of time that the urine firm accurate test results. detection signal remains stable, even after multiple insults. Thus, a need exists for efficient sensors that do not need Similarly, the thermochromic mixtures described herein can careful monitoring to produce accurate urine detection. An produce signals that remain stable for extended periods of absorbent article that incorporates such a sensor would be 30 time, while also being capable of withstanding multiple particularly beneficial. insults. Sensors that combine the pH indicator and thermo chromic mixtures can provide reliable back-up detection of SUMMARY urine. The sensors described herein provide a simple, user In accordance with one embodiment of the present disclo 35 friendly, cost-effective approach for rapid determination of Sure a method for detecting the presence of urine is described. wetness caused by urine. Additionally, the sensors described The method includes providing a urine indicating sensor with herein can be incorporated into absorbent articles Such as a matrix, the matrix having a pH indicator non-diffusively diapers and incontinent articles to assist in detecting urine immobilized thereon, the pH indicator being capable of a Wetness. color transition when in contact with urine. Urine is contacted 40 Referring to FIG. 1, one embodiment of a sensor 20 that with the matrix of the sensor and the presence of urine is can beformed according to the present disclosure will now be determined based on whether the pH indicator undergoes a described in more detail. As shown, the sensor 20 includes a color transition. matrix 22. In general, the matrix 22 can be made from any of In another embodiment of the present disclosure, a method a variety of materials through which the urine is capable of for detecting the presence of urine is described. The method 45 passing. For example, the matrix 22 can be a porous mem includes providing a urine indicating sensor with a porous brane formed from synthetic or naturally occurring materials, matrix, the matrix having a mixture ofathermochromic mate Such as polysaccharides (e.g., cellulose materials such as rial and a temperature change agent disposed thereon, the paper and cellulose derivatives, such as cellulose acetate and temperature change agent, when brought into contact with nitrocellulose); polyether Sulfone; polyethylene; nylon; poly urine, being capable of causing a temperature change in the 50 vinylidene fluoride (PVDF); polyester, polypropylene; silica; thermochromic material resulting in a color transition. Urine inorganic materials, such as deactivated alumina, diatoma is contacted with the matrix of the sensor and the presence of ceous earth, MgSO4, or other inorganic finely divided mate urine is determined based on whether the thermochromic rial uniformly dispersed in a porous polymer matrix, with material undergoes a color transition.