Abstract:
A tampon applicator has a barrel and a plunger telescopically mounted within the barrel. In a preferred embodiment, one or both of the barrel and plunger is made of a water dispersible material, and is exposed to a source of infrared radiation to minimize surface stickiness on initial contact with moisture. In an alternative embodiment, the barrel or plunger can be coated with a water dispersible material prior to exposure to infrared radiation.

Description:
RELATED APPLICATION 
     This application is a continuation application of U.S. patent application Ser. No. 09/245,732, filed Feb. 8, 1999, now abandoned, which in turn is a continuation-in-part application of U.S. patent application Ser. No. 09/119,439, filed Jul. 20, 1998, now abandoned, which in turn is a continuation of U.S. patent application Ser. No. 08/788,472, filed Jan. 28, 1997, now U.S. Pat. No. 5,782,794, which issued Jul. 21, 1998. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field Of Invention 
     The present invention is directed to an improved tampon applicator. More particularly, the present invention is directed to a tampon applicator having a plastic-type body or coating that has been treated. Even more particularly, the tampon applicator is either molded of a polymer resin, or coated with a polymer resin, with the outside surface of the applicator then treated with infrared radiation. 
     Consumers desire tampon applicators that make pledget insertion easier, more convenient and less messy. In particular, for environmental reasons as well as for convenience of disposal, consumers desire applicators, especially tampon applicators, that are both biodegradable and water-soluble. An example of a water-soluble polymer used for making flushable applicators is polyvinyl alcohol (also referred to herein as “PVOH”). 
     However, PVOH, in particular, is known to become sticky on contact with moist surfaces or under humid conditions. Heat treatment of the PVOH applicator provides crystallization that increases water resistance, but too much heat makes PVOH unacceptably stiff and brittle. 
     The present invention overcomes the disadvantages described above associated with tampon applicators made from water-soluble polymers in an efficient manner, and provides tampon applicators either made from, or coated with, water-soluble polymers that are able to withstand exposure to moisture, but are not unacceptably stiff. The present invention accomplishes the foregoing by heating only the outside of the applicator with infrared radiation. 
     U.S. Pat. No. 5,782,794, the grandparent of the present application, discloses a novel set of plasticizers suitable for use with PVOH that, in conjunction, produce a molded product having improved stability, ease of molding, and utility for tampon applicators. The disclosure of U.S. Pat. No. 5,782,794 in its entirety is incorporated herein by reference. 
     2. Description of the Prior Art 
     Tampon applicators typically are constructed from two telescoping tubes. One tube, a barrel, encloses the pledget, and the other tube, a plunger, is used to eject the pledget out of the barrel during insertion. Thus, it is essential that the tubes telescope smoothly to facilitate ejection. Any stickiness or other adhesions between the two tubes can result in poor ejection of the pledget, which in turn can make insertion of the pledget difficult, painful, or impossible. One solution to the foregoing problem is to make the diameter of the plunger less than the diameter of the barrel. However, if the plunger is much less in diameter than the barrel to prevent sticking together, the plunger will most likely disassemble from the barrel. 
     Furthermore, the ability of the barrel to be inserted smoothly, without dragging on the delicate vaginal tissue, is very important not only for users comfort but also for proper insertion of the pledget. Once again, any stickiness or adhesion sites on the outer surface of the barrel will impede proper insertion. 
     Tampon applicators formed from certain polymer resins, when dry, have glide characteristics similar to traditional plastic tampon applicators. Thus, such polymer resin tampon applicators would be expected to have optimal qualities for insertion, minimal drag on insertion and smooth telescoping of the barrel and plunger. In addition, these polymer resin tampon applicators remain dispersible and biodegradable on disposal in water. 
     However, the very ability of the polymer resin tampon applicators to disperse in water also creates certain drawbacks. Water-soluble polymer resins, can become sticky on contact with moist surfaces, bodily fluids or under humid conditions. Thus, tampon applicators formed from polymer resins tend to become tacky in the very environment for which it is designed. This in turn makes insertion more difficult, since the outer tube can become gummy or tacky upon insertion. Another potential problem should such a polymer resin applicator be exposed to moisture, is that the barrel and plunger may not telescope properly. The barrel and plunger may even become glued together, requiring a much greater force to eject the tampon pledget from the applicator. Additionally, humidity from the environment can permeate the packaging used to store the polymer resin tampon applicator and, thus, cause the same problems. Humidity may even cause the applicator to stick to the wrapper. 
     SUMMARY OF THE INVENTION 
     Accordingly, it is an object of the present invention to provide a water dispersible tampon applicator that has been treated with infrared radiation to avoid or minimize adverse moisture effects on the tampon applicator. 
     It is another object of the present invention to provide a polymer tampon applicator that has been treated with infrared radiation so that the applicator will not become sticky or begin to biodegrade upon initial contact with moist surfaces, bodily fluids or ambient humidity. 
     It is a further object of the present invention to provide a cardboard tampon applicator that has been coated with a water-soluble resin and then treated with infrared radiation so that the applicator will not become sticky or begin to biodegrade upon initial contact with moist surfaces, bodily fluids or ambient humidity. 
     It is still a further object of the present invention to provide a polymer tampon applicator that has been treated with infrared radiation so that the outside surface is crystallized to increase water resistance, yet the applicator remains flexible and, thus, usable. 
     Accordingly, the present invention discloses a tampon applicator having a barrel and a plunger that is telescopically mounted within the barrel. Either or both the barrel or plunger is made of, or coated with, a water dispersible polymer. The barrel or plunger is exposed to or treated with infrared radiation to minimize surface stickiness thereof when exposed to moisture. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of a tampon applicator employing a preferred method of the present invention; and 
     FIG. 2 is a diagram of a preferred method of treating a tampon applicator according to the present invention. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring to the drawings and, in particular, FIG. 1, there is a tampon applicator generally represented by reference numeral  10 . The applicator  10  has an outer tube or barrel  12  and an inner tube or plunger  14 . The barrel  12  preferably has a curved or petal tipped end  18 , and a plunger insertion end  22 . The barrel  12  preferably has a plurality of fingergrips  16 . The plunger  14  has an insertion end which has an edge  24 . Upon assembly, pledget  20  is located within barrel  12 , and plunger  14  is inserted in end  22  of the barrel. The edge  24  of plunger  14  will act against pledget  20  when the plunger is moved to eject the pledget through and out of end  18  of barrel  12 . 
     The barrel  12  and plunger  14  can be made of any water dispersible material. Examples of suitable water dispersible polymers are microbial polyesters such as poly(b-hydroxy butyrate)(“PHB”), poly(b-hydroxy butyrate)-co-(b-hydroxy valerate)(“PHBV”), poly(hydroxy acids), aliphatic polyesters, polycaprolactone (“PLC”), starch, cellulose acetate and cellulose diacetate. 
     Alternatively, either or both the barrel  12  and plunger  14  may be made of other materials, and then coated with a water dispersible polymer. Any of the water dispersible polymers set forth above may be used as the coating for the barrel or plunger. 
     Although either or both the barrel and plunger may be made of, or coated with, the water dispersible polymer, it is preferable that both the barrel and plunger are either made of, or coated with, the water dispersible polymer. 
     In one preferred embodiment, barrel  12  and plunger  14  are made of one water-soluble polymer resin. In a second embodiment, the barrel is made of the water-soluble polymer resin, and the plunger is made of another material, such as cardboard. 
     The tampon applicator assembly includes the barrel  12  and plunger  14  assembled together with the pledget  20  in the barrel. As shown in FIG. 2, the tampon applicator assembly is placed in a rotating carrier  26 . The barrel  12  and plunger  14  are rotated in the rotating carrier  26  while the carrier is subjected to infrared (or “IR”) radiant heater or heaters (hereinafter “IR Source”)  28 . As shown in FIG. 2, the heater  28  is preferably positioned approximately six inches from the carrier  26 . As can be understood, the distance of the IR source  28  from the tampon applicator may be modified. However, as the distance of the IR source from the tampon applicator is modified, the temperature generated by the IR source  28  and the length of time of IR exposure will require adjustment as would be evident to those in the art. 
     The barrel  12  and plunger  14  are preferably treated with the IR Source  28  positioned about six inches from the carrier  26  for about five to about sixty seconds. The temperature of the IR Source is preferably from about 700° F. to about 2500° F. The effect of the IR treatment is time-temperature dependent. Thus, when the temperature of the IR Source is higher, the length of time required for IR exposure will decrease. 
     The temperature of the IR source  28  and the time period of IR exposure will be a function of the water-soluble polymer resin used. The polymer resin is heated to a level just below the melting point of the polymer resin. The infrared treatment affects the outer surface of the tampon applicator  10  by inducing high temperature molecular crystallinity along the backbone of the polymer resin. The polymer should not be heated to the melting point since only the cystallization of the outermost layer of the polymer resin is desired. The crystallization results in a more hydrophobic surface thereby providing a less sticky surface. However, since only the outermost layer of the polymer resin is crystallized by exposure to the IR source  28 , the overall flexibility of the tampon applicator is not substantially diminished as seen with prior art methods. 
     Examples of melting point ranges of several polymers that may be used with the present invention are listed below in Table 1. 
     
       
         
               
               
             
           
               
                 TABLE 1 
               
               
                   
               
               
                 POLYMERS 
                 MELTING POINT ° C. 
               
               
                   
               
             
             
               
                 Polycaprolactone (PCL) 
                 58-60  
               
               
                 Poly(b-hydroxy butyrate) 
                 40-180 
               
               
                 Poly (b-hydroxy butyrate)-co-(b-Hydroxy 
                 40-180 
               
               
                 Valerate) (PHBV) 
               
               
                 Aliphatic Polyesters 
                 200 
               
               
                 Cellulose Acetate (CA) 
                 240 
               
               
                   
               
             
          
         
       
     
     The examples of melting points set forth in Table 1 is intended only to provide a guideline. The melting point ranges of any specific polymer is available from the manufacturer of that particular polymer. 
     The most preferred conditions for infrared treatment of tampon applicators made of, or coated with, PVOH are: 
     
       
         
               
               
               
             
               
               
               
             
           
               
                   
                   
               
               
                   
                   
                 Temperature (° F.) of 
               
               
                   
                 Time (seconds) 
                 IR Source 
               
               
                   
                   
               
             
             
               
                   
               
             
          
           
               
                 Condition A 
                 40 
                 1325 
               
               
                 Condition B 
                 20 
                 1750 
               
               
                   
               
             
          
         
       
     
     This infrared treatment does not destroy, deform or degrade the petals of the applicator. Thus, this entire tampon applicator can be treated, whereas other known treatments would affect the petals. In prior treatments, the petals required protection during treatment, i.e. only the applicator body minus the petals could be treated. 
     U.S. Pat. No. 5,782,794, discussed above, is directed toward the application of the present invention for tampon applicators either made of, or coated with, PVOH. This patent illustrates that tampon applicators treated with infrared treatment demonstrate substantially improved performance in comparison with the conventional, non-IR treated PVOH applicators. A home use test of 100 respondents was performed. Specifically, tampons having (1) PVOH barrels infrared treated as set forth above (with untreated cardboard plungers); and (2) untreated applicators having barrels and plungers of traditional polyethylene were tested. 
     
       
         
               
               
               
               
               
             
           
               
                   
               
               
                   
                 # Preferring 
                 # Preferring 
                   
                   
               
               
                   
                 IR Treated 
                 Untreated 
                 No 
                 Preference 
               
               
                 Attribute 
                 PVOH 
                 Polyethylene 
                 Preference 
                 Ratio 
               
               
                   
               
             
             
               
                 Easy to insert 
                 32 
                 29 
                 39 
                 +1.1 
               
               
                 Comfortable to 
                 29 
                 25 
                 46 
                 +1.1 
               
               
                 Insert 
               
               
                 Easy to Eject 
                 32 
                 29 
                 45 
                 +1.1 
               
               
                 From Applicator 
               
               
                 Easy to Grip 
                 25 
                 22 
                 53 
                 +1.1 
               
               
                 Overall Comfort 
                 28 
                 20 
                 52 
                 +1.2 
               
               
                 Smoothness of 
                 27 
                 23 
                 35 
                 +1.1 
               
               
                 Applicator 
               
               
                 The applicator 
                 38 
                 38 
                 24 
                   1.0 
               
               
                   
               
             
          
         
       
     
     A similar study was conducted comparing untreated PVOH applicators to traditional, untreated polyethylene applicators. All applicators were the same in size, shape, dimensions and fingergrips. The results below show that consumers clearly preferred the untreated polyethylene applicators to untreated PVOH applicators. 
     
       
         
               
               
               
               
               
             
               
               
               
               
               
             
           
               
                   
               
               
                   
                 # Preferring 
                 # Preferring 
                   
                   
               
               
                   
                 Untreated 
                 Untreated 
                 No 
                 Preference 
               
               
                 Attribute 
                 PVOH 
                 Polyethylene 
                 Preference 
                 Ratio 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                 Easy to insert 
                 13 
                 43 
                 28 
                 −2.1 
               
               
                 Comfortable to 
                 14 
                 42 
                 28 
                 −2.0 
               
               
                 Insert 
               
               
                 Easy to Eject 
                 11 
                 38 
                 35 
                 −1.9 
               
               
                 From Applicator 
               
               
                 Easy to Grip 
                 20 
                 15 
                 49 
                 +1.1 
               
               
                 Overall Comfort 
                 8 
                 22 
                 54 
                 −1.4 
               
               
                 Smoothness of 
                 8 
                 43 
                 33 
                 −2.4 
               
               
                 Applicator 
               
               
                 The applicator 
                 26 
                 40 
                 18 
                 −1.4 
               
               
                   
               
             
          
         
       
     
     In summary, the results of these two tests show consumers clearly prefer the infrared treated PVOH (as compared to untreated polyethylene applicators) over untreated PVOH applicators. When comparing the preference ratios derived from the first experiment with infrared treated PVOH applicators (center column, below) versus untreated PVOH applicators the difference is obvious. This demonstrates the dramatic difference in product acceptability that is conferred by the infrared treatment of the present invention. 
     
       
         
               
               
               
             
               
               
               
               
             
           
               
                   
                   
               
               
                   
                 Preference Ratio 
                 Preference Ratio 
               
               
                   
                 IR Treated PVOH 
                 Untreated PVOH 
               
               
                   
                   
               
             
             
               
                   
               
             
          
           
               
                   
                 Comfortable to insert 
                 +1.1 
                 −2.0 
               
               
                   
                 Easy to insert 
                 +1.1 
                 −2.1 
               
               
                   
                 Easy to eject 
                 +1.1 
                 −1.9 
               
               
                   
                 Easy to grip 
                 +1.1 
                 +1.1 
               
               
                   
                 Smoothness of applicator 
                 +1.1 
                 −2.4 
               
               
                   
                 The applicator 
                 +1.0 
                 −1.4 
               
               
                   
                 Overall comfort 
                 +1.2 
                 −1.4 
               
               
                   
                   
               
             
          
         
       
     
     Accordingly, the IR treated PVOH applicator has similar consumer acceptance ratings to the traditional polyethylene applicator, even before taking into account the consumer preference for flushable and biodegradable applicators. This is a substantial improvement over the results for the untreated PVOH applicator. Furthermore, the IR treated PVOH may have scored even better with a treated PVOH plunger instead of the cardboard plunger used in the test. 
     The consumer testing results set forth above demonstrate that the advantages of treating with infrared heat tampon applicators made from, or coated with, water-soluble polymers. It is believed by the applicants that the present invention is as effective with the polymer resins disclosed herein as has been proven with the consumer test studies conducted with PVOH. 
     Thus, it will be obvious to one of ordinary skill in the art that the foregoing description and drawings are merely illustrative of certain preferred embodiments of the present invention, and that various obvious modifications can be made to these embodiments in accordance with the spirit and scope of the appended claims.