Abstract:
In a tampon pledget, a quantity of moisture activated material is positioned in contact with, or adjacent to a layer of absorbent material used in forming the pledget. Upon contact with menses, the moisture activated material reacts in one of an endothermic and exothermic manner so that in use, the pledget, when forming part of a tampon can thermally alert a wearer when the pledget has reached its absorbent capacity.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates generally to tampon pledgets and more particularly to tampon pledgets that provide an indication to a user that a tampon in which the pledget is incorporated, is ready to be changed. 
       BACKGROUND 
       [0002]    Due to the impracticality associated with removing a tampon to ascertain whether or not it has reached its absorbent limit, it is typically difficult to determine the appropriate time for replacement. Currently there are no indicators that are built into a tampon to signal the consumer that the tampon is close to full capacity. The consumer, therefore, is left with having to rely on instinct when making the determination as to when to change the tampon. This can often result in the tampon being changed prior to reaching full saturation, or subsequent to reaching full saturation when the tampon is changed too late, thereby increasing the potential for leakage past the tampon. 
         [0003]    Based on the foregoing, it is the general object of the present invention to provide a tampon that employs some indication that allows a user to discretely determine when tampon change is necessary. 
       SUMMARY OF THE INVENTION 
       [0004]    The present invention resides in one aspect in a tampon pledget having at least two layers of absorbent material that are formed into the pledget. A quantity of moisture activated material is positioned in contact with and/or adjacent to one of the layers of absorbent material. Upon contact with menses, the moisture activated material reacts in one of an exothermic and an endothermic manner so that during use, the pledget, when forming part of a tampon, can alert a user when the absorbent capacity of the tampon has been reached. 
         [0005]    Preferably, where the reaction is endothermic, the above-described moisture activated material is made from at least one of salt hydrates, anhydrous salts and organic compounds. Where a salt hydrate is employed, it is preferable that the moisture activated material be at least one of sodium acetate, sodium carbonate, sodium sulfate, sodium thiosulfate, or sodium phosphate. Where anhydrous salts are used, it is preferable that the moisture activated material be at least one of ammonium nitrate, potassium nitrate, ammonium chloride, potassium chloride and sodium nitrate. When the moisture activated material is organic, the preferred materials include one or more of urea and xylitol. 
         [0006]    In an embodiment of the present invention, the moisture activated material is positioned in a packet with the packet being located between layers of material that are ultimately formed into the pledget so that upon formation of the pledget, the packet is located interior of an outer surface defined by the pledget. The packet can be formed from at least two layers of nonwoven material bonded together with the moisture activated material positioned therebetween. The nonwoven material can be bonded together by using one or more of adhesives, heat sealing, stitching, and ultrasonic bonding. The packet can also be formed from a single piece of nonwoven material folded over onto itself with the edges of the folded nonwoven material being bonded together in the above-described manner. Preferably, the moisture activated material is in particulate or powder form; however, the present invention is not limited in this regard as the moisture activated material can also be in sheet form without departing from the broader aspects of the present invention. 
         [0007]    In another embodiment of the present invention, rather than being positioned in the above-described packet, the moisture activated material is dispersed within, and on a surface of a first of the at least two layers of absorbent material. A second of the at least two layers of absorbent material is positioned over the surface of the first layer of absorbent material so that upon formation of the layers of absorbent material into the pledget, the moisture activated material is located interior of an outer surface defined by the pledget. Accordingly, where the pledget forms part of a tampon, once moisture absorbed by the pledget reaches the moisture activated material, an endothermic or exothermic reaction occurs which is discretely detectable by a user and provides an indication regarding the need to change the tampon. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]      FIG. 1  is a schematic plan view of a temperature-change packet for use in one embodiment of the present invention; 
           [0009]      FIG. 2  is a cross-sectional view of the temperature-change packet of  FIG. 1 ; 
           [0010]      FIG. 3  is a schematic plan view of a continuous length of temperature-change packets; 
           [0011]      FIG. 4  is a schematic plan view of the temperature-change packet of  FIG. 1  in place between layers of a tampon pledget; and 
           [0012]      FIG. 5  is a cross-sectional view of a tampon as described herein. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0013]    The tampon pledget of the present invention comprises a moisture activated material that produces either an endothermic or exothermic reaction upon contact with moisture. The moisture activated material reacts to (is “activated by”) contact with menstrual fluid by absorbing heat from, or releasing heat to, the surrounding area. The moisture activated material is located interior of an outer surface of the pledget. Accordingly, once activated, the moisture activated material causes a temperature change within the pledget that is detectable by a wearer of the tampon. A tampon typically includes a removal string at the distal end of the tampon. Preferably, the moisture activated material is disposed at or near the string end of the tampon, so that it will be activated when the tampon is near full saturation due to contact with bodily fluid. Preferably, there is substantially no moisture activated material at the insertion end (i.e., the proximal end) of the tampon. 
         [0014]    In use, the above-described tampon including the pledget having the moisture activated material forming a part thereof is inserted in the body. When the moisture activated material in the tampon comes into contact with menses, the user senses the temperature change and is thereby signaled that the tampon is ready to be replaced. 
         [0015]    The moisture activated material may be a heat-absorbing material that produces an endothermic reaction, such as sodium acetate, sodium carbonate, sulfate, thiosulfate, phosphate or anhydrous salts such as ammonium nitrate, potassium nitrate, ammonium chloride, potassium chloride, and sodium nitrate, or organic compounds such as urea or a sugar such as xylitol. 
         [0016]    Alternatively, the temperature-change material may be a heat-releasing material that produces an exothermic reaction such as aluminum chloride, aluminum sulfate, potassium aluminum sulfate or the like. 
         [0017]    The moisture activated material may be in particulate or powder form and may be packaged in between layers of a permeable, non-woven material to provide a temperature-change packet as shown in  FIG. 1  and  FIG. 2 . The temperature-change packet  10  includes the moisture activated material  12  that is disposed in between layers  14  and  16  of the permeable, non-woven material. The layers  14 ,  16  may be sealed together by an adhesive, heat seal, ultrasonic bond, stitching, or any other suitable means or any combination of the foregoing, to form a perimeter seal  18  around the moisture activated material. The layers  14  and  16  of the permeable, non-woven material may comprise spunbond polypropylene (SBPP), spunbond-meltblown-spunbond (SMS), thermally bonded webs, chemically bonded webs, through-air-bonded carded webs (TABCW), carded-and-needle-punched webs, hydro-entangled webs, cotton/polypropylene webs, PET (polyester) webs, spunlace, airlaids, meltblowns, apertured films, tissues, etc. Preferably, the permeable, non-woven material is suitable for high temperature processing (e.g., handling at temperatures of about 300° F. or higher). In a particular embodiment, the layers  14  and  16  are made from a composite comprising about 30% cotton and about 70% polypropylene fibers, by weight, and has a basis weight of 33 gsm (grams per square meter). A non-woven material found to be useful in making the packets is SH-PPC-33 manufactured by Shalag Nonwoven of Israel. Optionally, the layer  16  may be a folded-over portion of the layer  14 . 
         [0018]    Optionally, the layers  14  and  16  may comprise lengths of material with which a plurality of packets are formed to provide a length  20  of interconnected temperature-change packets  10  as shown in  FIG. 3 . The length  20  of temperature-change packets may be wound up in pancake rolls or traverse spools. A length  20  of temperature-change packets  10  may then be installed on a tampon manufacturing machine. The length  20  of temperature-change packets  10  may be unwound and cut into individual temperature-change packets  10  for incorporation into temperature-change pledgets. 
         [0019]    As shown in  FIG. 4 , a pledget  22  is formed by placing an individual temperature-change packet  10  on a first layer  24  of pledget material. A second layer  26  of pledget material is then placed on the first layer  24 . The pledget  22  is used to form a tampon with the temperature-change packet  10  therein near the string end of the tampon. 
         [0020]    In another embodiment of the present invention, a moisture activated material is dispensed on top of, and in the central area of, a first layer  24  of pledget material. A second layer  26  of pledget material is placed over the moisture activated material to sandwich the moisture activated material  12  between the layers  24  and  26  of pledget material. The layers  24 ,  26  of pledget material are used to form a temperature-change pledget that is used to form the tampon. Preferably, the moisture activated material is disposed near the string end of the tampon. 
         [0021]    In another embodiment, moisture activated material  12  is blended into the binder (polymer) and the absorbent (cellulose, cotton and/or rayon) fibers that form pledget material. For example, particles of moisture activated material  12  are blended into an airlaid web that is used to make layered pledget composites. The moisture activated material-containing airlaid web is incorporated into the pledget material so as to be concentrated near the string end of the tampon. 
         [0022]    A tampon  30  is shown in  FIG. 5 . The tampon  30  has a proximal end  32 , a distal end  34  and a removal string  36  attached at the distal end  34 . The tampon  30  comprises a moisture activated material as described herein, principally at the distal end  34 . There is substantially no moisture activated material at or near the proximal end  32 . 
         [0023]    The terms “first,” “second,” and the like herein do not denote any order, quantity, or importance, but rather are used to distinguish one element from another. In addition, the terms “a” and “an” herein do not denote a limitation of quantity, but rather denote the presence of at least one of the referenced item. 
         [0024]    Although the invention has been described with reference to particular embodiments thereof, it will be understood by one of ordinary skill in the art, upon a reading and understanding of the foregoing disclosure, that numerous variations and alterations to the disclosed embodiments will fall within the spirit and scope of this invention and of the appended claims.