Method and apparatus for indicating the conditions in an absorbent article

Abstract

A method and apparatus for gauging the levels of pH in the interiors of articles such as diapers, incontinence garments, pads, catamenial products, bedding, and would dressings are disclosed. This method and apparatus include sensing devices and relay systems for displaying the pH on the outside of the articles that provide visual and/or audible warnings that toxic levels are approaching and that it is time to remove and replace the article.

1 . A method for determining the remaining safe life of a diaper comprising the steps of:
 applying a diaper to a subject, said diaper having means for indicating by a visual color change the pH of the interior conditions of said diaper;   observing the color of the indicating means;   determining from the color of the indicating means whether the pH has reached a level at which the safe life of the diaper has ended.   
     
     
         2 . A diaper comprising:
 a liquid impervious outer layer having opposed side edges and opposed end edges connecting the side edges, said outer layer defining the shape and dimensions of the diaper, the diaper having a crotch portion adapted to engage the crotch of the wearer to capture and retain body waste material when the diaper is folded medially and worn engaging the waist and stomach areas;   an absorbent second layer adapted for receiving body waste material, the absorbent pad having opposed side and end edges, the absorbent pad being slightly narrower than said first layer, the side edges of the first layer extending around and over the side edges of the second layer, thereby providing a barrier against body waste material from escaping through the back of the diaper or through the side edges of the pad;   a means for measuring pH, located within said absorbent second layer, said means being capable of indicating multiple changes in the pH of the interior environment of the diaper; and   a means for conveying said indication of multiple changes to the exterior of the diaper.   
     
     
         3 . The diaper of  claim 2 , wherein multiple changes in pH are indicated by a visual color change. 
     
     
         4 . The diaper of  claim 1 , wherein the means capable of indicating multiple changes in pH indicates said changes audibly. 
     
     
         5 . A method for monitoring changing conditions in a diaper comprising the steps of:
 applying the diaper of  claim 3  to a subject; and   observing said color change over time.   
     
     
         6 . A method for determining the remaining safe life of a diaper, comprising the steps of:
 applying the diaper of  claim 3  to a subject;   observing said color change over time; and   determining from the rate of change of said visual indicator the amount of time remaining in the safe life of the diaper.   
     
     
         7 . A diaper comprising:
 an electrochemical indicator for measuring pH of an interior environment of said diaper, said electrochemical indicator being located within an absorbent core layer of said diaper, wherein said electrochemical indicator is operable to measure a series of pH levels over time and generate a series of electrical signals based on said series of pH levels;   a pathogenic prediction unit operable to receive said series of electric signals, wherein said pathogenic prediction unit performs curve matching on said series of pH levels and determines a time at which said interior environment of said diaper is predicted to become pathogenic based on a selected curve.   
     
     
         8 . A diaper as recited in  claim 7 , wherein the electrochemical indicator includes an electrochemical cell having a pH sensor and a reference electrode. 
     
     
         9 . A diaper as recited in  claim 8 , wherein the electrochemical indicator further includes a terminator coupled to the electrochemical cell by a number of conductive lines, wherein said terminator is coupled to the pathogenic prediction unit. 
     
     
         10 . A diaper as recited in  claim 9 , wherein said pathogenic prediction unit displays a current pH of the interior environment of the diaper. 
     
     
         11 . A diaper as recited in  claim 10 , wherein said pathogenic prediction unit displays the time at which the interior environment of the diaper is predicted to become pathogenic. 
     
     
         12 . A diaper as recited in  claim 10 , wherein said pathogenic prediction unit displays an amount of time remaining until the interior environment of the diaper is predicted to become pathogenic. 
     
     
         13 . A method of predicting the remaining safe life of a diaper, comprising the steps of:
 measuring a series of pH levels of an interior environment of said diaper;   matching a selected curve to said series of pH levels by comparing said series of pH levels with a series of curves; and   predicting a time at which said interior environment of said diaper will have a pathogenic pH based on said selected curve.   
     
     
         14 . A method of predicting the remaining safe life of a diaper as recited in  claim 13 , further comprising the step of indicating a time remaining until the predicted time at which the interior environment of the diaper will have a pathogenic pH. 
     
     
         15 . A method of predicting the remaining safe life of a diaper as recited in  claim 13 , further comprising indicating a time at which the diaper should be changed based on the predicted time at which the interior of environment of the diaper will have a pathogenic pH. 
     
     
         16 . A method of predicting the remaining safe life of a diaper as recited in  claim 15 , wherein said indicating a time at which the diaper should be changed includes a visual indicator. 
     
     
         17 . A method of predicting the remaining safe life of a diaper as recited in  claim 16 , wherein said visual indicator includes a color change. 
     
     
         18 . A method of predicting the remaining safe life of a diaper as recited in  claim 15 , wherein the indicating a time at which a diaper should be changed includes an audible signal.