US3794038A

US3794038A - Disposable diaper with tape fastener having a release liner which also provides a means to grip and remove the topsheet

Info

Publication number: US3794038A
Application number: US00298142A
Authority: US
Inventors: K Buell
Original assignee: Procter and Gamble Co
Current assignee: Procter and Gamble Co
Priority date: 1972-10-16
Filing date: 1972-10-16
Publication date: 1974-02-26
Anticipated expiration: 1991-02-26
Also published as: MX143627A; BE806078A; FI54994C; IE38366B1; DK136753C; NL7314135A; SE385540B; GB1444433A; DE2351273A1; FI54994B; ES203722U; IT995884B; NO133218C; AT332327B; CH559012A5; ATA872973A; DK136753B; CA1039901A; NO133218B; IE38366L

Abstract

A disposable diaper is provided with a pressure-sensitive tape fastener. The tape is affixed at one end to the liquid retaining backsheet of the diaper and the other end is superposed on a release liner of a generally conventional design from which the tape may be stripped immediately prior to diaper application. The release liner for the tape overlies a portion of the face of the diaper. A first portion of the release liner is secured to the topsheet of the diaper and a second portion thereof is essentially unattached, providing a means to grasp the liner. At least the portion of the topsheet secured to the release liner is releasably secured to the remainder of the diaper so that it may be removed therefrom (after the soiled diaper is removed from the wearer) by gripping and pulling on the unattached portion of the release liner.

Description

nite States atent I191 Buell 1 DISPOSABLE DIAPER WITH TAPE FASTENER HAVING A RELEASE LINER WHICH ALSO PROVIDES A MEANS TO GRIP AND REMOVE Tl-IE TOPSIIEET [75] Inventor: Kenneth Buell, Cincinnati, Ohio [73] Assignee: The Procter & Gamble Company, Cincinnati, Ohio 22 Filed: omits, 1972 [21] Appl. No.: 298,142

511 Int. Cl A411) 13/02 [58] Field of Search 128/284, 286, 287, 290

[56] I References Cited UNITED STATES PATENTS 2,002,368 5/1935 Fancher 128/284 3,180,335 4/1965 Duncan et 31.. 128/287 3,620,217 11/1971 Gellert 128/284 3,636,952 1/1972 George 128/287 3,642,001 2/1972 Sabee 128/287 3/1972 Gellert 128/287 6/1972 Ralph 128/287 Primary Examiner-Charles F. Rosenbaum 5 7] ABSTRACT A disposable diaper is provided with a pressuresensitive tape fastener. The tape is affixed at one end to the liquid retaining backsheet of the diaper and the other end is superposed on a release liner of a generally conventional design from which the tape may be stripped immediately prior to diaper application. The

' release liner for the tape overlies a portion of the face of the diaper. A first portion of the release liner is secured to the topsheet of the diaper and a second portion thereof is essentially unattached, providing a means to grasp the liner. At least the portion of the topsheet secured to the release liner is releasably secured to the remainder of the diaper so that it may be removed therefrom (after the soiled diaper is removed from the wearer) by gripping and pulling on the unattached portion of the release liner.

19 Claims, 6 Drawing Figures DISPOSABLE DIAPER WITH TAPE FASTENER HAVING A RELEASE LINER WHICH ALSO PROVIDES A MEANS TO GRIP AND REMOVE TIIE TOPSIIEET BACKGROUND OF THE INVENTION This invention relates to disposable diapers and more particularly to such diapers which have a topsheet which is, at least in part, releasably secured to the remainder of the diaper thereby allowing the separable portion to be disposed of in a manner different from that used for the remainder of the diaper.

The present invention is an improvement on the invention of copending U. 5. Pat. Application Ser. No. 222,065 which is commonly assigned to the assignee hereof.

As discussed more fully in the aforementioned copending patent application, it is decidedly advantageous to be able to conveniently dispose of the fecal soil on a disposable diaper along with a minimum amount of the diaper in a water closet while disposing of the remainder of the diaper separately, e.g., in the trash. One way of achieving this end is to provide a liquid-pervious topsheet on the diaper at least a portion of which is releasably secured e. g., attached by perforations) to the remainder of the diaper.

SUMMARY OF THE INVENTION The present invention provides an improved means of locating and grasping the removable portion of the topsheet of a disposable diaper for separation. The improved grasping means consists of the tape fastener release liner (or a portion thereof) which is releasably secured to at least one of the tapes which are used to secure the diaper about the wearer. One end of the release liner is secured to a removable portion of the liquid pervious topsheet of the diaper while the other end is essentially free, providing a convenient grasping means once the tape has been removed and the diaper used.

BRIEF DESCRIPTION OF THE DRAWINGS While the specification concludes with claims which particularly point out and distinctly claim the subject matter regarded as the invention, it is thought that the invention will be better understood from the following description taken in conjunction with the accompanying drawings in which:

FIG. 1 is a fragmentary plan view of a preferred embodiment of the present invention;

FIG. 2 is a fragmentary, vertical cross-sectional view of the embodiment of FIG. 1 taken at line 22;

FIG. 3 is a fragmentary, vertical cross-sectional view of an alternate embodiment of the present invention showing the tape separated from the release liner;

FIG. 4 is a perspective view of the in-use position of an exemplary overall diaper of the present invention;

FIG. 5 is a plan view of a preferred embodiment of a liquid-pervious topsheet for use in the present invention; and

FIG. 6 is a perspective view illustrating the use of the tape release liner for stripping the topsheet from the diaper.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Turning now to the drawings, FIG. 1 illustrates one corner of a disposable diaper. While the present invention can be used with a broad variety of diaper configurations, an exemplary and preferred diaper configuration is that of U. S. Pat. Re 26,151 which issued Jan. 31, 1967 to R. C. Duncan et a]., which is incorporated herein by reference. Briefly, such a diaper is typically comprised of a liquid retaining backsheet II, for example a polyethylene film. A portion 11a of the backsheet preferably wraps around the lateral edges 12 of the diaper and extends over a portion of the face thereof to provide containment of liquid wastes therein. A second portion lllb of the-backsheet 111 extends beyond the waistband forming edges 12' and is folded to the position shown in FIG. 4 to provide a barrier against the wicking of liquid wastes. While the following description assumes this preferred juxtaposition of backing sheet 11 with the edges 12 and 12' and the face of the diaper it is to be understood that the invention does not require the same as will be appreciated by those in the art.

Superposed on the backsheet I1 is a pad of liquid absorbent material which can be creped paper or any other suitable material. In a preferred embodiment, and as described herein, the absorbent pad is comprised of a layer of communited wood pulp I3 encased in sheets of tissue paper having at least moderate wet strength; lower sheet 14 and upper sheet 15 which are suitably secured about the communited pulp l3.

Superposed on the absorbent pad is a topsheet designated generally by the numeral I6. Although the only requirement for the topsheet is that it be liquid pervious, allowing liquid wastes to pass through to the absorbent pad, a preferred topsheet 116 will also be hydrophobic so that little or no liquid is retained on it and thereby in contact with the wearers skin. A preferred material for use as the topsheet I6 is a non-woven wetlaid fabric of rayon with a binder such as ethyl and methyl methacrylates in a non-ionic latex with selfcrosslinking properties as manufactured by Rohm and Haas and sold under the designations Rhoplex PIA-8 and Rhoplex PIA-24, of about 4 to 5 mils thickness, 19 gm/sq.yd. basis weight and having a dry tensile strength of about 1000 gm./inch with the machine direction and about 550 gm./inch across the machine direction. The machine direction will preferably be placed transversely of the diaper (running between the lateral edges I2) and such an orientation will be assumed hereinafter.

As disclosed in the aforementioned copending patent application, by making the topsheet 16, or a portion thereof, separable from the remainder of the diaper the fecal soil on the diaper can easily and conveniently be disposed of in the water closet without the need to similarly dispose of the absorbent pad. In this connection, it should be noted that a topsheet I6 formed as described above provides a surprisingly effective filter, allowing only highly liquid and essentially sterile wastes to pass therethrough. Such filtered wastes can consequently be disposed of by the means normally used for solid wastes, e.g., the trash can, without creating an unsanitary condition.

The present invention contemplates the use of a variety of separable topsheets or topsheet portions including those disclosed in the aforementioned copending patent application. When using a diaper as disclosed in the aforementioned Duncan et al., patent the preferred topsheet 16 is that shown in FIG. 5 with a width of about 11 be inches and a length of about 7% inches. A central removable portion 17 (surrounded by a peripheral area of about 9 /2 inches by 14 k inches is defined by a line of weakness comprised of perforations 18 and cuts 19.

The perforations 18 can comprise 0.080 inch cuts separated by 0.020 inch of uncut topsheet 16 in the cross machine direction (lengthwise of the diaper) and 0.030 inch cuts separated by 0.030 inch of uncut topsheet in the machine direction (across the width of the diaper). The cuts 19 provide transitions to facilitate separating the corners of the central portion 17 of the topsheet l6 and preferably extend about one inch transversely of the diaper (between the lateral edges 12) and about I longitudinally of the diaper (parallel to the lateral edges 12). The cuts 19 extend across one another in an X configuration merely for convenience in forming with the use of conventional cutting and scoring equipment without the need for elaborate roll dies.

The peripheral area 20 of the topsheet 16 is preferably attached to the remainder of the diaper by essentially liquid insoluble adhesives, applied in the region 21 of FIGS. 2 and 5, as described in the Duncan et al., patent. If the diaper configuration being used requires the use of pleat forming adhesive bonds which are located within the removable area 17 of the topsheet, water (urine) soluble adhesives are preferably used for such bonds. A particularly suitable water soluble adhesive is low molecular weight polyvinyl alcohol, approximately 88 percent hydrolyzed, as produced by E. I. du- Pont de Nemours & Company and sold under the trade designation Elvanol 51-05. By applying an aqueous solution containing about 12-28 percent, by weight, of Elvano] 51-05 at a temperature of from about 100 F to about 200 F, bonds can be formed which are satisfactory to hold the diaper in the desired configuration for initial diaper application but which dissolve in use (from urine), allowing easy separation of the central removable portion 17 of the topsheet 16.

In one alternate embodiment, not illustrated, the topsheet can be releasably secured to the remainder of the diaper by other than lines of weakness defining a removable central portion; instead, the entire topsheet can be releasably secured to the remainder of the diaper so that it is held in place during application but separable thereafter. Releasable securement for this embodiment could be achieved by the use of the aforementioned Elvanol 51-05 adhesive or by embossing.

Although safety pins or other means can be used to hold a disposable diaper about the wearer, pressuresensitive tapes are a convenient and widely accepted means to achieve this end. FIG. 4 shows a complete diaper of conventional construction including the features of the present invention, held in the in-use configuration by tapes 22. Returning to FIG. 2, the tape 22 is shown as it is applied to the diaper prior to use. A first portion 22a of the tape 22 is secured to the underside of the backsheet 11. A release liner is provided to prevent inadvertent contact between the second portion 22b of the tape 22 and other objects prior to its use. U. S. Pat. No. 3,646,937 which issued Mar. 7, 1972 to D. A. Gellert and which is assigned to the assignee of the present invention discloses a plurality of desirable configurations for such release liners and is incorporated herein by reference. A typical and satisfactory release liner for use with the present invention consists of a 1 inch wide sheet of polypropylene having a tensile strength of about 15 lbs/inch with a silicone surface treating on the tape-contacting side to facilitate release.

The release liner used with the present invention differs in certain important details from that disclosed in the Gellert patent. First, it is preferably segmented into

portions

23a and 23b. The portion 23a extends around the edge of the diaper far enough so that the tape 22b is not attached thereto. Consequently the tape 22b has no tendency to tear the backsheet 11 at the edges thereof when the diaper is applied. Portion 23a is preferably secured by any suitable adhesive 26 to the diaper, and more particularly to the portion 11a of the backsheet which overlies a portion of the absorbent pad, as a matter of convenience to avoid the necessity of disposing of it separately.

The remaining portion 23b of the release liner extends beyond the portion lla of the backsheet and overlies a portion of the central removable portion 17 of the topsheet, being secured thereto by a strong adhesive bond in the region 24. One suitable adhesive for use in this application is a modified acrylate adhesive as made by the Minnesota Mining & Manufacturing Company of St. Paul, Minnesota and presently sold under the designation Scotch Brand No. SLl-250-6l2 (lot 620). Preferably, this same adhesive will be used as the adhesive 26 to simplify the assembly of the diaper as discussed more fully hereinafter.

It is important that the release liner portion 23b be essentially unsecured to the portion 11a of the backsheet in order that it can function as will hereinafter be described. Preferably, there is no securement at all; however, a readily releasable securement, e.g., peelable, is within the meaning of essentially unsecured as used herein. One simple means to assure the desired lack of attachment is to avoid the use of adhesives between release liner portion 23b and backsheet portion 11a. An alternate and preferred means is the use of a tab 25 of colored polyethylene film or the like juxtaposed between release liner portion 23b and backsheet portion 11a. An adhesive 26 such as that used on release liner portion 23a is also used on portion 23b, effecting adhesion between the portion 23b and the tab 25. This preferred configuration offers two primary advantages. The use of colored material for the tab highlights the presence thereof and consequently encourages the use of it (in conjunction with the release liner portion 23b, etc.) to remove the central portion 17 of the topsheet 16 and dispose of the fecal wastes thereon in the water closet as desired. In addition, use of the additional element, tab 25, actually simplifies the assembly of the diaper and tape/release liner/topsheet tear tab assembly when using equipment such as that described in copending U. S. Pat. Application Ser. No. 289,898 which is assigned to the assignee hereof, allowing the use of a relase liner which is a single sheet with uniform properties across its width. The liner is simply split into

portions

23a and 23b by a cutter as it is being laminated to the other layers (just prior to being affixed to the diaper).

If desired, the tab 25 can cover less than the entire underside of the essentially unsecured portion of the release liner portion 23b. If this is done, a small region of adhesive 26 which underlies said unsecured portion will be in contact with and releasably secured to the portion 11a of the backsheet ll, thereby preventing said unsecured portion from raising prematurely. A satisfactory way to provide releasable securement in this way is the provision of a hole of about Vs inch in diame ter (not illustrated) centrally in the tab 25.

FIG. 3 illustrates a variation of the invention, showing the elements thereof as they are just prior to the application of the diaper to the wearer; i.e., with the tape removed from the release liner. In this variation, the release liner 23b functions in the same manner as the release liner portion 23b of FIG. 2, being adhered to a tab a by adhesive 26' which adhesive also is secured to the separably attached portion 17 of the topsheet in the region 24'. An extension 25b of the tab 25a is provided and is initially integral therewith. A preferred material for use as the

tab

25a, 25b is an oriented poly propylene film of about 1% to 1 mil in thickness. The grain of the film is oriented across the width (the narrow dimension) of the tape 22b. The film is easily torn along the grain as the tape portion 22b is peeled from the release liner 23b. Tab portion 25b remains secured to the tape 22b but does not interfere with the functioning thereof. The remaining portions of the embodiment of FIG. 3 are similar to the corresponding portions of the embodiment of FIG. 2 and are similarly numbered, but including the prime designation. The advantage of this embodiment is that the tab portion 25b functionally replaces the more expensive release liner portion 23a and that the entire tape/release liner/- tab assembly can be easily assembled from minimum of components.

When the diaper is soiled, it is removed from the wearer by peeling or tearing the tape 22. Disposal of the fecal wastes contained in the diaper is then effected by pulling on the release liner portion 23b (or 23b) with the action shown in FIG. 6 as the diaper is held over a water closet or the like. The comparatively small amount of material which comprises the removable portion 17 of the topsheet 16 can readily be handled in water closets and the remainder of the sanitary waste system and the separation thereof from the remainder of the diaper is easily effected by pulling as illustrated.

The foregoing is illustrative of the invention but many modifications can be made to the embodiments described without departing from the essential concepts of the invention.

What is claimed as new is:

1. In a disposable diaper having a liquid retaining backsheet, a liquid absorbent pad and a separably attached liquid pervious topsheet, the improvement which comprises a tape means for securing said diaper to the wearer, a first portion of said tape means attached to said backsheet and a second portion of said tape means releasably held to a release liner, said release liner being attached to said liquid pervious topsheet add adapted for gripping and removing said topsheet.

2. The disposable diaper of claim 1 which is initially held in a pleated configuration by adhesive bonds to said separably attached topsheet, said bonds being formed from a water soluble adhesive.

3. The disposable diaper of claim 2 wherein said separably attached topsheet is the central portion of a topsheet and attached to the remaining portions thereof by lines of weakness.

4. The disposable diaper of claim 2 wherein said water soluble adhesive is polyvinyl alcohol.

5. The disposable diaper of claim 4 wherein said separably attached topsheet is the central portion of a topsheet and attached to the remaining portions thereof by lines of weakness.

6. The disposable diaper of claim 1 wherein said separably attached topsheet is the central portion of a topsheet and attached to the remaining portions thereof by lines of weakness.

7. The disposable diaper of claim 1 wherein a portion of said release liner has affixed to the face opposite said tape means a tab of colored material.

8. The disposable diaper of claim 6 wherein a portion of said release liner has affixed to the face opposite said tape means a tab of colored material.

9. In a disposable diaper having a liquid retaining backsheet, a liquid absorbent pad and a separably attached liquid pervious topsheet, the improvement which comprises a tape means for securing said diaper to the wearer, a first portion of said tape means attached to said backsheet and a second portion of said tape means releasably held to a release liner, said release liner being attached at one end to said separably attached topsheet and adapted for gripping and removing said topsheet and a tab of material underlying and secured to the portion of said release liner remote from said attachment to said topsheet.

lit). The disposable diaper of claim 9 which is initially held in a pleated configuration by adhesive bonds to said separably attached topsheet, said bonds being formed from a water soluble adhesive.

11. The disposable diaper of claim 10 wherein said separably attached topsheet is the central portion of a topsheet and attached to the remaining portions thereof by lines of weakness.

12. The disposable diaper of claim 10 wherein said water soluble adhesive is polyvinyl alcohol.

13. The disposable diaper of claim 12 wherein said separably attached topsheet is the central portion of a topsheet and attached to the remaining portions thereof by lines of weakness.

14. The disposable diaper of claim 9 wherein said separably attached topsheet is the central portion of a topsheet and attached to the remaining portions thereof by lines of weakness.

15. The disposable diaper of claim 9 in which said tab is of weak material and extends beyond said release liner and underlies and is attached to said tape means.

16. The disposable diaper of claim 15 wherein said separably attached topsheet is the central portion of a topsheet and attached to the remaining portions thereof by lines of weakness.

17. The disposable diaper of claim 16 which is initially held in a pleated configuration by adhesive bonds to said separably attached topsheet, said bonds being formed from a water soluble adhesive.

18. The disposable diaper of claim 15 wherein a portion a portion of said release liner is releasably secured to said diaper thereby retaining said release liner in place prior to its use.

19. The disposable diaper of claim 15 wherein said tab is of oriented polypropylene, the grain of which is oriented widthwise of said tape means.

mg? Y m1) STATES PATENT OFFICE I v CERTIFICATE OF CORRECTION Patent No. 1 50 Dated February 26, 1974 Invontofls) neth Buell i It: is certifigdthat: error afapears in the above-ide'fit ified patent and that said-Letters Patent are hereby corrected gs shown below:

's o 1" Column 1, line- 56; "taken at line 2-2" should read 7 -;taken 7 through the tape 22b and looking in the direction of arrows 2-2-. 1 1 f Column 2, line 2 9 Ir \municcil" 51mm read --fcomminutjed- C0lumn .2, lino "oommunited" read coi mn.fi.nuted-r.

Column 4 lint-251 3, f'tap 22b"*shon:1d,read wfiape poption 22b- Coliumn 4, fliho l4} toPo 22b" Shduidifead Q it ape" ia ox tioh" 2 2b l'um 5', line 6'0; *"add" should ia- -ando 2 sighed and Sealed this Zfid day of July 19 Attest: U "EDWARD -M.FLETCHER, :JR;- CQ ARSHAL DANNY Attesting Officer o v Commissioner of Patents

Claims

10. The disposable diaper of claim 9 which is initially held in a pleated configuration by adhesive bonds to said separably attached topsheet, said bonds being formed from a water soluble adhesive.