Diaper tape fastener
BACKGROUND OF THE INVENTION 
     The present invention relates to absorbent articles, and more particularly to disposable diapers. 
     A various assortment of disposable diapers have been proposed for use on infants. A number of such diapers have been provided with tape fasteners for securing the diaper about the infant during placement. The tape fasteners have generally taken the form of a tape strip having a securement portion which is covered by a release sheet, with the release sheet being removed from the securement portion of the tape strip during placement of the diaper to expose adhesive on the securement portion. While it has been found that parents prefer that the release sheet be secured to the diaper itself to eliminate the necessity for discarding the release sheet, it is also desirable that the tape fastener be made of economic construction to reduce the cost of the diaper to the consumer. 
     SUMMARY OF THE INVENTION 
     A principal feature of the present invention is the provision of a tape fastener for a disposable diaper of simplified construction and reduced cost. 
     The diaper has an absorbent pad assembly having an absorbent pad, a back surface, a front surface, and at least one side edge. The pad assembly has an area of a first thickness and a region of reduced thickness adjacent a side edge of the pad. The pad assembly has opening means extending through the pad assembly and the region of the pad, with the opening means being spaced from the side edges of the pad assembly and pad. The tape fastener comprises, a pressure-sensitive tape strip having a first end section secured to the back surface of the pad assembly with adhesive on the first end section being exposed through the opening means of the pad assembly, and a second securement end section extending past the side edge of the pad assembly. The tape fastener also has a sheet, such as a release sheet, having a first surface providing a relatively low affinity for adhesive on the tape strip and having a second surface facing the front surface of the pad assembly, with the adhesive exposed through the opening means being attached to the sheet adjacent one end thereof. 
     In one embodiment, the sheet extends from the opening means past the side edge of the pad assembly, with the other end of the sheet being attached to adhesive on the second end section of the tape strip. In another embodiment, the pad assembly has second opening means adjacent the side edge of the pad assembly and extending through the region of the pad, with adhesive of the first end section of the tape strip being exposed through the second opening means. The adhesive exposed through the second opening means is attached to the other end of the sheet adjacent the side edge of the pad assembly. 
     Thus, a feature of the present invention is that the sheet may be permanently retained against the front surface of the pad assembly, and need not be discarded after placement of the diaper. 
     Another feature of the present invention is that the sheet may be retained against the front surface of the pad assembly by adhesive on the tape strip. 
     Yet another feature of the invention is that the tape strip may be anchored to the sheet by adhesive on the strip and sheet which is attached through the opening means. 
     Still another feature of the invention is that the pad assembly may include a fluid impervious backing sheet which has lateral side margins covering side margins of the pad to minimize leakage from the pad. 
     A feature of the invention is that the pad region of reduced thickness facilitates attachment of the sheet and tape strip together through the pad. 
    
    
     Further features will become more fully apparent in the following description of the embodiments of this invention and from the appended claims. 
     DESCRIPTION OF THE DRAWINGS 
     In the drawings: 
     FIG. 1 is a perspective view of a tape fastener according to the present invention prior to placement on a diaper; 
     FIG. 2 is a fragmentary plan view of a disposable diaper showing the tape fastener of FIG. 1 as partially applied to the diaper; 
     FIG. 3 is a fragmentary plan view of the diaper showing the tape fastener of FIG. 1 as secured to the diaper; 
     FIG. 4 is a fragmentary plan view of the diaper of FIG. 3 showing a securement portion of a tape strip releasably attached to a release sheet in the tape fastener; 
     FIG. 5 is a fragmentary sectional view taken substantially as indicated along the line 5--5 of FIG. 4; 
     FIG. 6 is a fragmentary sectional view taken substantially as indicated along the line 6--6 of FIG. 4; 
     FIG. 7 is a fragmentary plan view of a diaper showing another embodiment of the tape fastener of the present invention; 
     FIG. 8 is a fragmentary plan view of a diaper showing another embodiment of the tape fastener of the present invention; 
     FIG. 9 is a fragmentary sectional view taken substantially as indicated along the line 9--9 of FIG. 8; 
     FIG. 10 is a perspective view of another tape fastener according to the present invention prior to placement on the diaper; and FIG. 11 is a fragmentary plan view of a disposable diaper showing the tape fastener of FIG. 10 as partially applied to the diaper. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring now to FIGS. 4 and 5, there is shown a disposable diaper generally designated 20 having an absorbent pad assembly 22 and a tape fastener 24 secured to the pad assembly 22. The pad assembly 22 has a front surface 26, a back surface 28, a side edge 30 , and an end edge 32 connecting the side edge 30. The pad assembly 22 has a fluid pervious cover sheet 34 defining a substantial portion of the front surface 26 of the pad assembly, a fluid impervious backing sheet 36 defining the back surface 28 of the pad assembly and having a lateral side margin 38 folded over and secured to the front surface 26 of the pad assembly, and an absorbent pad 40 intermediate the cover and backing sheets 34 and 36. The absorbent pad 40 has a side edge 42 located adjacent the side edge 30 of the pad assembly 22, such that the backing sheet margin 38 covers a side margin of the pad 40. The pad also has an edge 44 connecting the side edge 42 and spaced from the end edge 32 of the pad assembly 22. 
     As illustrated in FIGS. 2-6, the absorbent pad 40 has an area 39 of a first thickness extending throughout a substantial portion of the pad, and a region 41 of reduced thickness located adjacent the juncture of the side and end edges 42 and 44, respectively, of the pad 40. The region 41 of reduced thickness may be formed in any suitable manner, such as by compressing this portion of the pad. The compression of the pad 40 in the region 41 may be facilitated by first wetting the pad in this region. Alternatively, the pad 40 may have a reduced amount of material in the region 41 in order to obtain the reduced thickness in the region. If desired, a small amount of binder, such as Rhoplex HA-8, a trademark of Rohm and Haas, may be sprayed on the region 41 prior to compression thereof, in order to facilitate retention of the region 41 in its compressed state. 
     The pad assembly 22 also has opening means 46 extending through the pad assembly and the region 41 of the pad 40, with the opening means 46 being spaced from the side edge 30 of the pad assembly 22 and the side edge 42 of the pad 40. In this embodiment, the opening means 46 comprises a pair of spaced openings which are spaced longitudinally relative the diaper and laterally across an underlying tape strip, as will be seen below. It is understood that the opposed side of the diaper (not shown) would normally have a structure substantially similar to that described above, and would include a tape fastener as described below. 
     As shown in FIG. 1, the tape fastener 24 has an elongated pressure-sensitive tape strip 50 having a first end section 52, a second securement end section 54, and adhesive 55 on one surface of the strip. The tape strip 50 may have a folded over end 56 adjacent the outer end of the second end section 54 defining tab means for a purpose which will be described below. The tape fastener 24 also has a release sheet 58 having a first surface 60 providing a relatively low affinity for the adhesive 55 on the tape strip 50, and a second opposed surface 62 having a relatively high affinity for the adhesive 55 on the tape strip 50. The second surface 62 of one end 64 of the release sheet 58 is secured to the adhesive 55 on the second end section 54 of the tape strip 50, in order to retain the one end 64 to the tape strip, as described below. Either the first surface 60 or the second surface 62 of the release sheet 58 may be treated, as desired, to obtain the relative affinities for the adhesive 55. For example, the first surface of a paper strip, serving as the release sheet, may be treated with a silicon release coating to obtain the desired release characteristics from the adhesive, while the second surface remains untreated to obtain a firm bond with the adhesive. 
     As shown in FIG. 2, the first end section 52 of the tape strip 50 is secured to the back surface 28 of the pad assembly 22, such that adhesive on the first end section 52 is exposed through the openings or opening means 46. As illustrated in FIGS. 2 and 3, the other end 66 of the release sheet 58 is folded over the front surface 26 of the pad assembly 22, with the second surface 62 of the release sheet 58 facing the front surface 26 of the pad assembly. Since the region 41 of the absorbent pad 40 has a reduced thickness, the relatively thin cover sheet 34, backsheet 36, and pad region 41 present only a slight spacing between the other end 66 of the release sheet 58 and the first end section 52 of the tape strip 50. Accordingly, the other end 66 of the release sheet 58 may be pressed against the pad assembly, in order that the adhesive which is exposed through the opening means 46 contacts the second surface 62 of the release sheet 58. Since the second surface 62 of the release sheet 58 has a relatively high affinity for the adhesive 55 on the tape strip 50, the one end 64 of the release sheet 58 is retained by the adhesive on the second end section 54 of the tape strip, while the other end 66 is retained against the front surface 26 of the pad assembly 22 by the adhesive exposed through the opening means 46. Accordingly, the release sheet is retained against the front surface 26 of the pad assembly without use of separate adhesive on the release sheet 58, thus eliminating the cost of the separate adhesive for the release sheet. Moreover, the release sheet is retained in a manner such that the backing sheet margin 38 covers the side margin of the pad 40 to minimize leakage from the pad. 
     As shown in FIGS. 3-6, the second end section 54 of the tape strip 50, including the one end 64 of the release sheet 58, is folded over the front of the diaper and the second end section 54 of the tape strip 50 is releasably attached to the first surface 60 of the release sheet 58. Since the first surface 60 of the release sheet 58 has a relatively low affinity for the adhesive on the second end section 54 of the tape strip, the second end section of the tape strip may be readily removed from the release sheet 58 during placement of the diaper. Removal of the second end section 54 from the release sheet 58 is facilitated by the tab 56 at the outer end of the second end section, which is free of attachment to the release sheet 58 or the pad assembly 22. After the second end section 54 of the tape strip 50 is removed from the first surface 60 of the release sheet 58, in the position as shown in FIG. 3, the second end section 54 is properly located for securing the diaper 20 about the infant. Thus, securement of the diaper is accomplished without removal of the release sheet from the pad assembly, eliminating the necessity for separately discarding release sheets after placement of the diaper. 
     However, if desired, the second surface 62 of the release sheet or connecting strip 58 may be treated to provide a moderate affinity toward the adhesive 55 on the tape strip 50. In this configuration, the release sheet or anchoring strip 58 is retained in place during normal use of the diaper, as previously described. The user may peel the release sheet 58 from the diaper to expose fresh adhesive which was covered by the one end 64 of the release sheet 58. The fresh adhesive may be utilized to reposition the tape strip during further use of the diaper, or to secure the diaper in a rolled or folded configuration after use of the diaper for convenient disposal of the soiled diaper. 
     Another embodiment of the present invention is illustrated in FIG. 7, in which like reference numerals designate like parts. In this embodiment, the side edge 42 of the absorbent pad 40 is located adjacent the side edge 30 of the pad assembly 22, and the opening means 46 extends through the pad region 41 and is spaced from the pad side edge 42, as previously described. However, in this embodiment, the pad assembly has second opening means 70 extending through the pad assembly and pad region 41. The second opening means 70 is located adjacent the side edges 30 and 42 of the pad assembly 22 and pad 40, respectively, with adhesive on the first end section 52 of the tape strip 50 also being exposed through the second opening means 70. In this embodiment, the one end 64 of the release sheet 58 is located adjacent the side edge 30 of the pad assembly 22. Thus, the adhesive exposed through the second opening means 70 contacts the second surface 62 of the one release sheet end 64, and secures the one end 64 against the front surface 26 of the pad assembly 22, while the adhesive exposed through the first opening means 46 retains the other end 66 of the release sheet 58 against the pad assembly. Accordingly, the release sheet 58 is retained in place against the front surface of the pad assembly by the adhesive exposed through the spaced opening means 46 and 70. 
     Another embodiment of the present invention is illustrated in FIG. 8 and 9, in which like reference numerals designate like parts. In this embodiment, a release sheet 72 is releasably attached to the adhesive on the second end section 54 of the tape strip 50. The release sheet 72 is removed from the second end section 54 during placement of the diaper to expose the underlying adhesive which is then used to secure the diaper about the infant. In this embodiment, the sheet 58&#39;, which need not have a treated first surface 60, serves to obtain improved anchorage of the first end section 52 of the tape strip 50 to the diaper. The opening means 46 extends through the pad region 41 of reduced thickness, and the sheet 58&#39; is secured to the tape strip 50 through the opening means 46 and at the one end 64 of the sheet 58&#39;, thus preventing the first end section 52 of the tape strip 50 from being torn from the back sheet and being pulled away from the diaper. The release sheet described in connection with previous embodiments of the tape fastener also serves a similar function. 
     Another embodiment of the present invention is illustrated in FIGS. 10 and 11, in which like reference numerals designate like parts. In this embodiment, the release sheet 58 has an adhesive 63 defining its second surface 62, such that the adhesive 55 on the tape strip 50 and the adhesive 63 on the release sheet 58 are attached together through the opening means 46 when the release sheet is folded over and pressed against the pad assembly. Also, the adhesive 63 on the one end 64 of the release sheet 58 is attached to the adhesive 55 on the securement section 54 of the tape strip, and the tape strip is thus firmly anchored to the release sheet to prevent the tape strip from tearing from a relatively thin backing sheet, such as a backing sheet having a thickness of 0.3 to 0.9 mils. As before, the opening means 46 extends through the pad region 41 of reduced thickness. Also, it will be understood that the sheets 58 and 58&#39; of the diapers described in connection with FIGS. 1-9 may have adhesive on their second surfaces, if desired. 
     The foregoing detailed description is given for clearness of understanding only, and no unnecessary limitations should be understood therefrom, as modifications will be obvious to those skilled in the art.