NZ196521A

NZ196521A - Contoured disposable diaper

Info

Publication number: NZ196521A
Application number: NZ19652181A
Authority: NZ
Inventors: I Ness
Original assignee: Chicopee
Priority date: 1980-03-27
Filing date: 1981-03-17
Publication date: 1983-06-14
Also published as: ES267163Y; PT72739A; MX156552A; AU528786B2; JPH0111681Y2; ZA812046B; CA1152701A; BR8101753A; PT72739B; JPS56148901A; ES267163U; AU6732381A; JPS6270105U; AR245588A1

Description

"\ /? AMENDED under Sjfctlon of tfee Patents Act l95S^rom ASSISTANT COMMISSIONER OF PATENTS Priority Date(s): .. i Complete Specification Filed: Class: Publication Date: P.O. Journal, No: .. VI?. H ••••••• ,7HAR1981 Patents Form No. 5 Number PATENTS ACT 1953 Dated COMPLETE SPECIFICATION GATHERABLE, CONTOURED, DISPOSABLE DIAPER I^We CHICOPEE, of 317 George Street, New Brunswick, New Jersey United States of America, a company incorporated under the laws of the State of New Jersey, United States of America do hereby declare the invention for which ji/we pray that a Patent may be granted to pax/us, and the method by which it is to be performed, to be particularly described in and by the following statement: (followed by page la) 1 <&6S22 The invention relates to a contoured, gatherable, disposable diaper.

Background Of The Invention In recent years, disposable diapers have become 5 increasingly popular. As more and more disposable diapers • are being used, the incentive to continually improve the construction of such diapers, without significantly increasing their cost, has become stronger. For instance, a number of contoured, gatherable diapers have begun to 10 appear in the marketplace.

In almost all cases, commercial gatherable diapers contain a shaped absorbent pad having a generally hourglass shape. Such gatherable diapers wherein the crotch portion is narrower than the front and back waist portions are shown IS in U.S. Patent Nos. 4,050,462 and 3,860,003. The reason that such shaped absorbent pads have been used in gatherable diapers is to permit a better fit and to reduce bulk in the crotch area in order to make the diaper more comfortable.

One problem with using shaped absorbent pads is that such pads are more expensive to employ in diapers than pads having straight side edges. The present invention provides a contou,r_ed, gatherable disposable diaper which employs an absorbent pad having straight side edges that 25 do not need to be shaped. Therefore, the diaper produced in accordance with this invention can be produced less expensively than the gatherable diapers heretofore used commercially.

CHIC 6 22] o < r -1 i 1 NOW AMENDED I Summary Of The Invention j j The invention relates to an improved contoured, gatherable disposable diaper. The diaper of the ^.nvention includes an absorbent pad having two straight side edges which are 5 substantially parallel to /each otherJ The pad is contained between a water permeable'' facing sheet and a water impermeable backing sheet. The^/diaper has/ front and back waistline portions, two side edges, and a central crotch portion. The diaper also has elastic gathering means disposed adjacent 10 each of said side edges of the diaper in the central crotch portion, and transver/se restraining means cooperating with the facing sheet to ^prevent the diaper form opening fully in the crotch portibn to a fljt configuration.

/ The Prior Art Disposable diapers having elastic gathering means disposed along the latera'l edges of /the diapers are disclosed by Woon et al., in/U.S. Patei^t No. 4,050,462 and by Buell, in U.S. Patent/No. 3 ,860 ,i)03.

/ / Non-elastic disposable ^diapers which contain restraining means whichyprevent th^ crotch area from fully opening to its unrestrained configuration are disclosed by Schaar, ! f U.S. Patent No. 3,6 5 8', 063, Karami, U.S. Patent No. 3,929,134 7 ' / and Mesely et al. , U,/S. Patent No. 3,612,055. j Brief pescription Of The Drawings Fig. 1 /is a plan jiev of one embodiment of the disposable diaper/of the indention with the elastic gathering means 30 in the stretched condition, showing the location of the restraining means before final attachment, and with a port4on cut away to show interior detail; Fig/. 2 is a c^ross-sectional view taken along line 2-2 of Fig. 1; / Fig- 3 is a/perspective view showing one embodiment of )t:he disposable diaper of the invention; and , si 13 DEC 1982 I RECEIVED CHIC 622 j 965? AS AMETTOSD Summary Of The Invention The invention relates to an improved contoured, gatherable disposable diaper. The diaper of the invention includes an absorbent pad having two straight side edges which are substantially parallel to each other. The pad is contained between a water permeable facing sheet and a water impermeable backing sheet. The diaper has front and back waistline portions, two side edges, and a central crotch portion. The diaper also has elastic gathering means disposed adjacent each of said side edges of the diaper in the central crotch portion, and transverse restraining means maintaining two tucks in the facing sheet in the crotch portion,and cooperating with the facing sheet to prevent the diaper froTn opening fully in the crotch portion to a flat configuration.

The Prior Art Disposable diapers having elastic gathering means disposed along the lateral edges of the diapers are disclosed by Woon et al., in U.S. Patent No. 4,050,462 and by Buell, in U.S. Patent No. 3,860,003.

Non-elastic disposable diapers which contain restraining means which prevent the crotch area from fully opening to its unrestrained configuration are disclosed by Schaar, U.S. Patent No. 3,658,063, Karami, U.S. Patent No. 3,929,134 and Mesek et al., U.S. Patent No. 3,612,055.

Brief Description Of The Drawings Fig. 1 is a plan view of one embodiment of the disposable diaper of the invention with the elastic gathering means in the stretched condition, showing the location of the restraining means before final attachment, and with a portion cut away to show interior detail; Fig. 2 is a cross-sectional view taken along line 2-2 of Fig. 1; Fig. 3 is a perspective view showing one embodiment of the disposable diaper of the invention; and CHIC 622 Fig. 4 is a cross-sectional view taken along line 4-4 of Fig. 3.

Description Of The Preferred Embodiments 5 Fig. 1 illustrates one preferred embodiment of the invention as it would appear after all of the elements of the diaper have been assembled, prior to final attachment of the restraining means and release of the stretched elastic gathering means. Referring now to Figs. 1 and 2, 10 the diaper 11 of the invention includes an absorbent pad 10, a water permeable top facing sheet 12, and a water impermeable backing sheet 14. The absorbent pad 10 has two straight side edges 16, 18. Adjacent the two side edges of the diaper 50, 52, there are disposed two elastic 15 bands or strips 20, 22 which are shown in Fig. 1 in the elongated or stretched condition. When the elastic bands 20, 22 are allowed to relax and contract, the diaper 11 gathers, as is more clearly shown in Fig. 3 at 24, 26.

Tape tabs 28, 30 are located on the diaper 11 on the sides 20 toward the rear waistline portion of the diaper 11 for fastening the diaper 11 in place on a baby, in accordance with customary procedures.

The diaper 11 of the invention can be produced in a 25 relatively straightforward manner. The absorbent pad 10 is layed down on top of the water impermeable backing sheet 14, and the moisture permeable facing sheet 10 is then layed down on top of the absorbent pad 10. Two strips of elastic 20, 22 in the elongated or stretched 30 condition, are attached to the water impermeable backing sheet 14 in the central or crotch portion such that when the two sides 31, 33 of the water impermeable backing sheet 14 are folded over to form a "dam," the strips 20, 22 are located adjacent and essentially parallel to the 35 side edges 50, 52 of the diaper 11. The said dam is 1.

CHiC 622 . / // formed by folding over the two side edges 31, 33 of the backing sheet 14 and bonding said edges 31, 33 to the edges 32, 34 of the water permeable facing sheet 12, as is shown most clearly in the enlarged portion of Fig. 2. Two pairs of glue spots 36A, 36B, 38A, 38B are placed on the \ top surface of the water permeable facing sheet 12 at a position spaced inward of side edges 50, 52 of the diaper in the central, crotch portion, slightly toward the front waistline portion' 40 of the diaper 11 from an imaginary center line 41. The diaper 11 is then folded along fold lines 42, 44 so that the glue spots 36A, 36B, 38A, 38B adhere to another pair of spots 46A, 46B, 48A, 48B on the opposing side of the two fold lines 42, 44 to form two tucks 54, 56 (see Fig. 4). By adhering the top sheet 12 to itself as described above, the diaper 11 is restrained from opening fully to its flat, unrestrained configuration in the crotch portion, and it thereby assumes an arcuate cross section in the crotch portion, as is shown in Fig. 3.

The water impermeable backing sheet 14 is preferably made from 1 to 1-1/4 mil polyethylene film, although other water impermeable materials can be used. It is desirable to use a film with a matte finish or to emboss the surface of the film in order to enhance the softness, feel, and appearance of the diaper. One preferred emboss pattern is a fine diamond pattern having about 3-1/2 diamonds per inch.

The water permeable facing sheet 12 can be a nonwoven web made of a mixture of fibers consisting predominantly of inexpensive, short, cellulosic fibers such as short woodpulp fibers or cotton linters in amounts of 75 per cent to 98 per cent, the balance being textile length fibers such as rayon, as described in U.S. Patent No. 3,663,348 to Liloia et al. Nonwoven facing materials <1 ^ CHIC 622 suitable for use as facing sheets in disposable diapers of this invention can have fabric weights in the range of from about 0.5 to 5 ounces per square yard and densities of less than 0.15 grams per cubic centimeter, usually in 5 the range of from about 0.5 to about 0.1 grams per cc.

The dry strength of the facing sheet for a fabric having a weight of about 1.5 ounces per square yard is at least 0.15 pounds per inch of width in the machine direction and at least 0.1 pound per inch of width in the cross 10 direction. Such fabrics have good elongation, loft, softness, and drape characteristics. Facings may also be made of an apertured nonwoven fabric which is formed, for example, in accordance with the teachings of commonly assigned U.S. Patent Nos. 2,862,251, 3,081,514, and 15 3,081,515. Such facings can be made of rayon, polyester, polypropylene, or mixtures thereof. Furthermore, facings may also be made from other types of fabric such as those disclosed and described in U.S. Patent Nos. 3,485,706 to Evans. Such facings can be made of naturally occurring 20 fibers, synthetic fibers or blends thereof. Typical facing sheets made of polyester type fibers may have a weight of about 0.7 5 ounces per square yard.

The facing may be smaller than the backing (as shown in 25 Fig. 1), it may be the same size as and coterminous with the backing, or alternatively, the facing may be wider than the backing and have its side edges inwardly folded so that the facing is coterminous with the backing, as is shown in Fig. 3 of U.S. Patent No. 3,612,055. In the 30 latter case, the elastic members may 6e~secured above the inwardly folded side edges of the facing. In addition,^ facings may be made from non-apertured materials such as nonwoven isotropic webs or apertured polyolefin or polyester films having the desired moisture permeability. 35 In all of the aforementioned facings, the materials are 1 965 2 1 CHIC 622 preferably relatively hydrophobic so as to retard wicking within the facing.

The moisture absorbent pad of the desired shape having straight side edges, but usually smaller than the facing and backing, can be formed in accordance with the teachings of U.S. Patent No. 3,612,055 to Mesek et al. A prefered absorbent pad is composed of a loose batt of 100 per cent ground woodpulp wrapped in tissue paper. It is preferred to contour the woodpulp absorbent pad as is shown in Fig. 2, so that the middle one third of the pad contains as much pulp by weight as the total of the two outside thirds. To illustrate the order of magnitude contemplated, in a toddler size diaper, which is ordinarily the largest used for infants, about 50 grams of pulp is employed in the absorbent pad.

The absorbent pad is fastened to the moisture impermeable backing by standard procedures, such as by using thin strips of hot melt glue lines parallel to the sides of the diaper, with the glue lines being on approximately one half inch to one inch centers to anchor and stabilize the absorbent pad. While hot melt adhesive is preferred, cold liquid latex adhesive can also be employed if desired. The absorbent pad may also be compressed in thin lines on approximately one half inch centers to provide wicking channels to spread the liquid waste toward the ends of the diaper and prevent it from puddling in the crotch area. One preferred way of compressing the pad is to pass the pad through the nip of a pair of counterrotating rolls, the bottom roll being a smooth steel roll and the top roll having a series of wheels 3/32 inch wide on about 1/2 inch centers. The rolls are spaced apart with stops to a 1 mil gap. A pressure of about 500 to 2000 pounds per linear inch is used on the rolls. chic $^65 21 The elastic gathering means may be introduced into the diaper by known procedures. For instance, continuous strips or bands of stretched elastic material may be glued on the backing sheet in the central or crotch portion of the diaper, and after assembly of the diaper is completed, the bands may then be cut in the front and rear portion to snap back so that the front and rear portions of the diaper do not possess gathering properties, as is described by Buell in U.S. Patent No. 4,081,301.

An alternative and preferred method of inserting the elastic gathering member is the following: & 00 gs O LU a K> >5 Continuous strips or bands of elastic material are glued in the stretched condition to the entire length of the backing sheet extending from front to back, adjacent the side edges of the absorbent pad. Then, while the elastic strips are held in the stretched condition, the front and rear portions of the elastic strips are heated to elevated temperature to cancel the elasticity by causing a morphological change in the elastic material. The proportion of the length of the elastic bands that is "heat-cancelled" corresponds approximately to the space in Fig. 1 in which no elastic band is shown. Preferably, about the central half of the length of the diaper is elasticized. A preferred elastic band for use in this procedure is the thermoplastic rubber based film described by Kelly in U.S. Patent No. 4,173,612, or the reticulated version of the same film described by Kelly in U.S. Patent No.^*30S|Q<3Q . The disclosures of these two patents are incorporated herein by reference.

Approximately one half to three quarter inch strips of the film, either plain or reticulated, are employed. This film can be heat cancelled in the stretched condition so that it loses its elasticity by chic 6^9652 I heating the film to a temperature of about 65°C., up to about 82°C.

It is preferred that the elastic strips or bands be 5 located such that they are not covered by the side edges of the absorbent pad, as is shown in the drawings. This is especially the case when the elastic band is heat canceled as described above, since the heat cancellation step is thereby facilitated. However, this is not 10 essential, and in some cases the absorbent pad may extend over some or all of the elastic band.

The major novelty in this invention resides in the combination of the use of an absorbent pad having straight 15 side edges, elastic gathering means adjacent to the central or crotch portion of the absorbent pad, and the transverse restraining means cooperating with (and only with) the facing sheet for imparting an arcuate cross section to -the diaper in the crotch portion.

The location of the restraining means is an important feature of the invention. In one specific illustration of a toddler sized diaper having overall dimensions of 20 inches by 12-3/4 inches, the glue spots shown in Fig. 1 as 25 36a and 38a are located about 1-1/2 inches forward of the imaginary center line 41, and 2-3/4 inches in from the side edges 50, 52 of the diaper. The glue spots 36b and 38b are 1-1/4 inches forward of the spots 36a and 38a.

The fold lines 42, 44 are 1-1/4 inches in from the glue spots 36a, 36b and 38a, 38b, respectively.

The foregoing is merely a specific illustration of the location of the restraining means. The important thing is that such means be located such that the diaper has a generally arcuate cross section in the crotch portion.

This provides increased depth and absorbent in the crotch 1 CHIC 622 portion, with no significant sacrifice in comfort and fit The glue spots discussed above and illustrated in the drawings are merely illustrative of the restraining means 5 For instance, a short glue line or a series of glue spots could be used in lieu of the two pairs of glue spots shown. Conventional hot melt or latex adhesive can be used for the glue. -10- 196521

Claims

WHAT WE CLAIM IS: (NOW 1. A disposable diaper including an absorbent pad having two straight side edges that are substantially parallel to each other, said pad being contained between a water permeable facing / / sheet and a water impermeable backi/ig sheet, said diaper having / two side edges, front and back waistline portions and a central crotch portion, whereiii said diaper has elastic gathering means / disposed adjacent each of said sa.de edges of the diaper m the / central crotch portion, and whe/rein said diaper includes transverse restraining means cooperating with said facing sheet to prevent the dia/er from opting fully in the crotch portion to a flat configuration. 2. The disposatje diaper c/f Claim 1 wherein said transverse restraining means comprises adhesive means for maintaining two tucks in said /facing she^t in the crotch portion, each of said tucks being spaced respectively inwardly from the sides of said diaper./ / J / 3. The disposable diaper of Claim 2 wherein said adhesive means comprises a plurality of individual glue spots. 4. The disposable /Siaper of Claim 2 wherein said adhesive means ccimprises twp glue lines. 5. Thi. disposable diaper of Claim 2 wherein said diaper is folded along twcy fold lines extending longitudinally the length of said diaperjwherein the facing sheet is adhesively joined to itself by the /transverse restraining means to form said tucks iiy the crotcj portion and wherein each tuck individually encompasses/one of said fold lines, / ' rf I -10- 196521 WHAT WE CLAIM IS: • *

1. A disposable diaper including an absorbent pad having two straight side edges that are substantially parallel to each other, said pad being contained between a water permeable facing sheet and a water impermeable backing sheet, said diaper having two side edges, front and back waistline portions and a central crotch portion, wherein said diaper has elastic gathering means disposed adjacent each of said side edges of the diaper in the central crotch portion, and wherein said diaper includes transverse restraining means maintaining two tucks in said facing sheet in the crotch portion, and cooperating with said facing sheet to prevent the diaper from opening fully in the crotch portion to a flat configuration.

2. The disposable diaper of Claim 1 wherein said transverse restraining means comprises adhesive means maintaining said two tucks in said facing sheet in the crotch portion, each of said tucks being spaced respectively inwardly from the sides of said diaper.

3. The disposable diaper of Claim 2 wherein said adhesive means comprises a plurality of individual glue spots.

4. The disposable diaper of Claim 2 wherein said adhesive means comprises two glue lines.

5. The disposable diaper of Claim 2 wherein said diaper is folded along two fold lines extending longitudinally the length of said diaper wherein the facing sheet is adhesively joined to itself by the transverse restraining means to form said tucks in the crotch portion and wherein each tuck individually encompasses one of said fold lines. 'ftz PArmromog' 20 DEC 1983 ) v ^ "/ -11- 196521

6. The disposable diaper of Claim 1, 2, 3 or 4 wherein the transverse restraining means are located slightly toward the front waistline portion of an imaginary transverse center line of the diaper.

7. The disposable diaper of Claim 5 wherein the transverse restraining means are located slightly toward the front waistline portion of an imaginary transverse center line of the diaper. WEST-WALKER, McCAZE per: ATTORNEYS FOR THE APPLICANT