IE50608B1

IE50608B1 - Elasticized disposable diaper

Info

Publication number: IE50608B1
Application number: IE2495/80A
Authority: IE
Original assignee: Colgate Palmolive Co
Priority date: 1979-12-03
Filing date: 1980-12-01
Publication date: 1986-05-28
Also published as: MX151896A; GR72463B; IT1128626B; JPS5691002A; BR8007022A; GB2063677A; PT72042B; IE802495L; PH18591A; NL8005688A; CA1143506A; ZA806525B; AU532029B2; BE886447A; GB2063677B; FR2471149B1; JPH0376941B2; FR2471149A1; ES262259U; AU6466680A

Abstract

A disposable diaper having elasticized crotch seals formed from elastic members 34,36 secured to the backing sheet 22 within 3/4 inch (1.9 cms) of the absorbent pad 26 and under such tension as to minimize transverse pleats in the crotch area.

Description

This invention relates to disposable diapers and more particularly to an elasticized and contoured diaper.

In the past elasticized contoured diapers have been developed such as that disclosed in the United States Patent to Buell, No. 3,850,003, issued January 14, 1975, for Contractable Side Portions for Disposable Diaper wherein elastic strips are secured to the crotch portions of the diaper and spaced at least inch (1.9 cms) from the absorbent pad to form elasticized crotch seals for securement over the legs of the infant to prevent loss of fluid from the interior of the diaper along the legs of the infant. The elasticized strips were placed more than inch (1.9 cms) from the absorbent pad in order to prevent pleats forming transversely in the crotch area of the diaper.

Another diaper is presently in production in which the elasticized strips are ο less than inch (1.9 cms) from the absorbent pad for the production of transverse pleats in the crotch area of the diaper for the purpose of increasing the absorbency capacity at the crotch area of the diaper. - 2 50608 However, it has been found that these pleats can act as channels resulting in excessive diaper leakage and the pleats in the crotch area are uncomfortable for the infant's bottom when it is sitting, especially while the diaper is not saturated.

The present invention overcomes the disadvantages of both of the prior art diapers. The elastic members are placed according to the present invention less than inch (1.9 cms) from the absorbent pad thereby reducing the width of the crotch seals rendering the diaper more comfortable. However, the elasticized strips are so positioned that the tension therein is maintained at a level such that substantially no transverse pleats are formed in the pad of the diaper in use, thereby eliminating excessive leakage and the discomfort caused by the prior art pleats prior to saturation.

The present invention provides a disposable diaper which is contoured in an hour-glass type of configuration and has an absorbent body between a top sheet and a backing sheet, elastic members being secured to the backing ο sheet less than inch (1.9 cms) from the absorbent body, the tension in the said elastic members being such that there will be pleats along the said crotch seals and no significant number of pleats across the crotch area of the diaper when the diaper is in use on the body.

Thus according to the present invention a disposable diaper comprises a backing sheet, an absorbent pad disposed on the said backing sheet, the said absorbent pad being of an hour-glass or waisted shape defining ears spaced from crotch area, an upper tissue wadding sheet overlying the said pad, a top sheet overlying the said absorbent pad and upper tissue wadding sheet, the said top sheet being secured to the said backing sheet at at least the two opposite peripheral side edges thereof, opposed elastic members each being secured to the said backing sheet in at least the central portion - 3 50608 of a respective one of the said two opposite peripheral side edges to define crotch seals along the side edges of the said diaper, and at least a portion of the said elastic members being secured to the said upper tissue wadding sheet, the said elastic members being le ss than inch (1.9 cms) from the said absorbent pad in the crotch area, the tension on the said elastic members being such that there will be pleats along the said crotch seals and no significant number of pleats across the crotch area of the said diaper when the diaper is in use on the body.

The said top sheet may be bonded to the said backing sheet by hot melt jg adhesive, or heat sealing techniques.

The invention may be put into practice in various ways and one specific embodiment will be described to illustrate the invention with reference to the accompanying drawings, in which:Figure 1 is a plan view of a diaper constructed in accordance with the present invention; Figure 2 is a transverse sectional view taken along the plane of line 2-2 in Figure 1 through the crotch portion of the diaper; and Figure 3 is a transverse view taken along the plane of line 3-3 in Figure 1.

In the accompanying drawings, like reference numerals designate similar parts throughout the various views. Reference numeral 10 generally designates an elasticized and contoured disposable diaper constructed in accordance with the present invention. The diaper is of an hour-glass configuration having a crotch area 12 and two portions of greater width defining four ears 14, 16, 18 and 20. The diaper includes a backing sheet 22 of an impervious material such as flexible plastics film material, - 4 50608 e.g. polyethylene or polypropylene film. A top sheet 24, preferably of a typical non-woven bonded (e.g. by resin latex) rayon or rayon-polyester fibre sheet or a spun bonded sheet of polyethylene or polypropylene fibres, is sealed, preferably by lines of hot melt adhesive to the backing sheet along the periphery of the diaper. An absorbent pad 26 is disposed between the top sheet 24 and the backing sheet 22 and may be of conventional wood fluff (e.g. from chemical, semi-chemical or thermo-mechanical pulp) or the like. An upper tissue wadding sheet 28 and a lower wadding sheet 30 are provided on either face of the pad 26, the pad and the wadding sheets conforming generally to the hour-glass shape. A pair of elasticized strips 34 and 36 provided with adhesive on at least the bottom surface thereof and optionally on the top surface or applied separately in these locations thereof, are bonded with the adhesive to the backing sheet 22 immediately q adjacent the pad 26 and less than inch (1.9 cms) from the pad. The adhesive may be used in the form of a continuous array of discrete spots or lines, and it may be any conventional hot melt or pressure-sensitive adhesive and, preferably, one that, at ambient temperatures, is flexible and extensible (i.e. elastic-like) in nature. The strips 34 and 36 overlie and are adhered to the eared portions of the upper wadding sheet 28, as shown in Figure 3, and are arranged so that the tension on the heat sealed backing sheet and top sheet provided by the elasticized strips is such that pleats are formed in the crotch .seals formed by the elasticized strips and portions 40 and 42 outwardly thereof and between the elasticized strips and the pad, while no significant number of pleats are formed in the crotch area 12. The top and bottom wadding sheets may be the conventional paper or tissue sheets heretofore used in the art (i.e. cellulosic fibres) or may be formed of hydrophobic fibres (e.g. polyester, polyethylene or polypropylene) or rendered hydrophobic by suitable and conventional treatments (e.g. by resins). - 5 0608 The elastic strips 34 and 36 may vary in width but are generally from 3 to 12 mms wide, e.g. 5 to 10 mms, with a range of about 5 to 8 mms being preferred. The width of the adhesive may be somewhat greater or lesser than that of the elastic strips and typically for a 6 mm wide elastic strip would range from about 4 to 12 mm. Typical thicknesses of the strips 34 and 35 range from a few mils (e.g. 1 to 5) to 15 or 20 mms, with the higher ranges more general for foams.

One convenient process for making the diapers of this invention employs a conventional fluff forming technique, using wadding sheets to carry the fluff pad between them. This composite material is cut to shape and then laid down on a larger size backing sheet 22. Before applying the elastic strips 34 and 36, the diaper, while going through the fabricating machine, is maintained by suitable means (e.g. clamping fingers) in its fully extended position and the elastic strips are applied and secured to the diaper backsheet at an elongation of 40 to 80% beyond their relaxed length and preferably at about 50 to 70% elongation and more preferably at 55 to 65% elongation (e.g. typically 60% elongation). The top sheet 24 is then applied and secured as by adhesive means to the backing sheet around their peripheral edges (outwardly of the pad 26). As described above, the top sheet 24 may be, and preferably is, secured to the elastic strips 34 and 36 as well. Reference is made to U.S. Patents Nos. 4,022,456 and 4,081,301 for further specific details as to apparatus and methods for assembling elastic absorbent structures as generally herein contemplated.

By the foregoing construction, upon contraction of the elastic strips only the back sheet and other elements secured to the elastic strip are contracted to form pleats and the overall diaper generally assumes a bowl-like shape which facilitates placing the diaper on the baby and permits a better fit as well. - 6 50608 The elastic strips 34 and 36 may be of any suitable construction and materials such as conventional rubberized (or otherwise elastomerized) fibres or may be simply a strip of elastomeric resin or foamed resin which may or may not be provided with adhesive. Such strips are generally available as double sided transfer tapes (e.g. 3M Co. St. Paul, Minnesota tape No. 465 high tack pressure-sensitive tape).

Claims

1. A disposable diaper comprising a backing sheet, an absorbent pad disposed on the said backing sheet, the said absorbent pad being of an hour-glass or waisted shape defining ears spaced from a crotch area, an upper tissue wadding sheet overlying the said pad, a top sheet overlying the said absorbent pad and upper tissue wadding sheet, the said top sheet being secured to the said backing sheet at at least the two opposite peripheral side edges thereof, opposed elastic members being secured to the said backing sheet in at least the central portion of a respective one of the said two opposite peripheral side edges to define crotch seals along the side edges of the said diaper, and at least a portion of the said elastic members being secured to the said upper tissue wadding sheet, the said o elastic members being less than inch (1.9 cms) from the said absorbent pad in the crotch area, the tension in the said elastic members being such that there will be pleats along the said crotch seals and no significant number of pleats across the crotch area of the said diaper when the diaper is in use on the body.

2. A disposable diaper as claimed in Claim 1 in which the said top sheet and the said backing sheet are bonded together along the peripheral edges thereof. - 7 50608

3. A disposable diaper as claimed in Claim 1 or Claim 2 in which the said top sheet is bonded to the said backing sheet by hot melt adhesive, or heat sealing techniques.

4. A disposable diaper as claimed in any one of Claims 1 to 3 in which 5. The elastic members are elongated by 50% to 70% before being secured to the backing sheet, whilst the backing sheet is in its fully extended position.

5. A disposable diaper as claimed in Claim 1 substantially as specifically described herein with reference to the accompanying θ drawings.