CA1152701A - Gatherable, contoured, disposable diaper - Google Patents
Gatherable, contoured, disposable diaperInfo
- Publication number
- CA1152701A CA1152701A CA000373787A CA373787A CA1152701A CA 1152701 A CA1152701 A CA 1152701A CA 000373787 A CA000373787 A CA 000373787A CA 373787 A CA373787 A CA 373787A CA 1152701 A CA1152701 A CA 1152701A
- Authority
- CA
- Canada
- Prior art keywords
- diaper
- side edges
- crotch portion
- disposable diaper
- fold lines
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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- Orthopedics, Nursing, And Contraception (AREA)
Abstract
GATHERABLE, CONTOURED, DISPOSABLE DIAPER
Abstract A gatherable, contoured disposable diaper is disclosed.
The diaper includes an absorbent pad having straight side edges. 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. Elastic gathering means are disposed adjacent both of said side edges of the diaper in the crotch portion. The diaper includes restraining means cooperating with the facing sheet to impart a generally arcuate cross section to the diaper in the crotch portion.
Abstract A gatherable, contoured disposable diaper is disclosed.
The diaper includes an absorbent pad having straight side edges. 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. Elastic gathering means are disposed adjacent both of said side edges of the diaper in the crotch portion. The diaper includes restraining means cooperating with the facing sheet to impart a generally arcuate cross section to the diaper in the crotch portion.
Description
' ~lS~Ol CHIC 622 GATHERABLE, CONTOURED, DISPOSABLE DIAPER
Specification The invention relates to a contoured, gatherable, disposable diaper.
Background Of The Invention In recent years, disposable diapers have become 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 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 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 contoured, gatherable disposable diaper which employs an absorbent pad having straight side edges that 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.
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li52701 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 ~ide edges. The pad is contained between a water permeable facing sheet and a water impermeable backing sheetO The diaper has front and back waistline portions, two side edtes, and a central crotch portion. The diaper also has elastic gathering means disposed adjacent each of said side edges of the diaper in the crotch portion, and restraining means cooperating with the facing sheet to impart a generally arcuate cross section to the diaper in the crotch portion~ -According to a still further broad aspect of the ; present invention there is provided a disposable diaper including an absorbent pad having two straight side edges that 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 two side edges, front and back waistline portions and a central crotch portion. The diaper has elastic gathering means disposed adjacent each of the side edges of the diaper in the central crotch portion. The diaper further includes transverse restraining means cooperating with the facing sheet to prevent the diaper from 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 ~o. 4,050,462 and by Buell, in U.S. Patent No. 3,8609003.
Non-elastic disposable diapers which contain restrain-ing means which prevent the crotch area from fully opening to its unrestrained configuration are disclosed by Schaar, i UOS~ Patent ~o. 3,658,063, Karami, U.S. Patent ~o. 3,929,134, ~ and Mesek et alO, U.S. Patent ~o. 3,612,055.
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1~52701 -2a_ Brief Description of the Drawin~s 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 ` ~ 15 ~ 0 ~ CHIC 622 Fig. 4 is a cross-sectional view taken along line 4-4 of Fig. 3.
Description Of The Preferred Embodiments Fig. 1 illustrates one preferred embodiment of the invention as it would appear after all of the elements o~
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, the diaper 11 o~ 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 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 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 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 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 side edges 50, 52 of the diaper 11. The said dam is llS~l CHIC 622 formed by olding 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 bac~ing 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 115Z70~ 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 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 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 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 fibers, synthetic fibers or blends thereof. Typical facing sheets made of polyester type fibers may have a weight of about 0.75 ounces per square yard.
The facing may be smaller than the backing (as shown in 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 latter case, the elastic members may be secured above the inwardly folded side edges of the facing. In addition, facings may be made from non-apertured materials such as nonwoven sotropic webs or apertured polyolefin or polyester films having the desired moisture permeability.
In all of the aforementioned facings, the materials are ~ CHIC 622 1:~5;~70~
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 ~.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.
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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 suell in U.S. Patent No.
4,081,301 An alternative and preferred method of inserting the elastic gathering member is the following:
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 caus-ing a morphological change in the elastic material. Theproportion 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 in Kelly, Canadian Patent Application Serial No. 337,737, and assigned to the same assignee as this application. 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 !c,i llS~l CHIC 622 heating the film to a temperature of about 65C., up to about 82C.
It is preferred that the elastic strips or bands be 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 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 side edges, elastic gathering means adjacent to the central or crotch portion of the absorbent pad, and the 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 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 l~S~l 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.
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.
l~SZ701 -SUPPLEMENTARY DISCLOSURE
Since Applicant made the invention as described in the Principal Disclosure herein, Applicant has dis-covered certain improvements, and these improvements constitute the subject matter of the Supplementary Disclosure herein, The improvements are described in the following text together with the accompanying drawings in which:
Figure 5 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;
Figure 6 is a cross-sectional view taken along line 6-6 of Figure 5;
Figure 7 is a perspective view showing one embodiment of the disposable diaper of the invention; and Figure 8 is a cross-sectional view taken along line 8-8 of Figure 7.
Like numerals represent like parts in all Figures.
Turning to Figure 5, it is noted that although in Figure 1 the elastic strips 20 and 22 were illustrated as being in only the crotch area, Figure 5 illustrates these strips as extending the full length of the diaper.
In addition, while Figure 1 illustrates glue spots 36A, 36B, etc., Figure 5 illustrates glue lines 36B, 38B, 46B and 48B. As seen in Figure 8, the two longi-tudinal fold lines 42 and 44 run through the tux 54 and 56 at the bottoms thereof.
The facing sheet 12 was described in the Principal Disclosure as being made of an apertured non-woven fabric, it has been discovered that a non-apertured non-woven fabric may also be used. A preferred facing is a print bonded, carded web composed of 50 weight .
l~LSZ701 percent polyester staple fibers and 50 weight percent rayon staple fibers, with the bonded web weighing about 250 grains per square yard, ~n the Principal Disclosure, a preferred way of compressing the pad was described. This same pre-ferred way is used in the present disclosure with the following parameters: the pressure used to make the glue lines, on a 9 1/2 to 10-inch pad, which has a 4-inch ID air pressure cylinder, which presses the two rolls together, is of the order of 35 psig.
Having regards to the fastening of the elastic material, it will be appreciated that in accordance with the present embodiment, the elastic material is glued on the backing sheet for the entire length of the diaper, me glue lines or glue spots are considered to be transverse restraining means which cooperate with the facing sheet to prevent the diaper from opening to the flat or unrestrained configuration. me restraining means are called transverse because the restraining action acts in the transverse direction.
As mentioned in the Principal Disclosure, the location of the restraining means is an important feature of the invention, In one specific illustration of an infant size diaper having overall dimensions of about 15 inches by 11 1/2 inches, the glue lines 46 and 48 begin about 3/4 inch forward of the imaginary center line 41, and are each about 1/2 inch long and are about 4 inches in from the side edges 50, 52 of the diaper.
me fold lines 42, 44 are about 1-1/8 inches from the glue lines 46, 48, respectively.
The restrained facing sheet forms a pocket in the crotch area (shown as 58, in Figure 7), and therefore the diaper of this invention is more effective in holding fecal matter than is a diaper without the restraining -means, - -' ; - ' : ' - :
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Another advantage shown by this diaper is more effective utilization of the entire absorbent pad, compared with hourglass shaped pads. In an hourglass pad, liquid must wick first longitudinally, and then laterally from the narrower crotch portion in order to reach the lateral extremities of the pad at the front and rear waistline ends. That is not necessary with the rectangular pad used in this diaper, wherein liquid flooding the crotch portion need only wick longitudinally to reach the extremities of the pad.
To illustrate the improved effective capacity discussed in the previous paragraph, a diaper of this invention was compared with a commercial shaped, gather-able diaper using the demand wettability tester described by Lichstein in U. S. Patent No. 3,952,584. The test measures the total amount of water absorbed by the sample from a point source--in this case, the center of the diaper.
The diaper of this invention weighed 67 grams The absorbent pad utilized a densified layer, as taught by Mesek et al in U, S. Patent No. 3,612,055, and wick-ing channels, as taught by Mesek in U. S. Patent No.
4,259,387.
The commercial diaper had an hourglass shaped absorbent pad and weighed 70 grams.
In the demand wettability test, the diaper of this invention absorbed 750 milliliters of water while the commercial diaper absorbed only 490 milliliters of water. The improved performance exhibited by the subject diaper is due in large part to the rectangular shape of the absorbent pad versus the hourglass shape of the pad in the commercial diaper. For reasons that were dis-cussed~above, the rectangular shape is more efficient in utilizing the absorbent capacity of the extremities of the pad. The densified layer and the wicking channels in - the diaper of this invention also contribute to the ability of the liquid to reach the extremities of the pad. But this is partially offset, however, by the fact that the densified layer has a lower liquid holding capa-city than the undensified portion of the absorbent pad.
In another test utilizing the same two diapers, a diaper is fastened in place on a life sized doll that is constructed so as to be able to void into the diaper to simulate actual use, The test liquid is 1.59% saline solution ~ontaining a red dye, The test solution is poured through the doll into the diaper in 150 milliliter incre-ments, with a twenty minute wait between increments, The test is stopped at the first indication of a leak of the liquid out of the diaper. The test is carried out with the doll being placed on an absorbent underpad of known weight, so that the amount of leaked liquid can be deter-mined, The diapers are also weighed before and after the test so that the amount of liquid absorbed by the diaper can be determined, The results of the test were as follows:
Weight of Weight of Absorbed Liquid Leaked Liquid Diaper of this invention 363,5 gms Trace (0,01 gm3 Commercial Diaper 343 gms 4.3 gms ,~
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Specification The invention relates to a contoured, gatherable, disposable diaper.
Background Of The Invention In recent years, disposable diapers have become 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 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 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 contoured, gatherable disposable diaper which employs an absorbent pad having straight side edges that 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.
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li52701 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 ~ide edges. The pad is contained between a water permeable facing sheet and a water impermeable backing sheetO The diaper has front and back waistline portions, two side edtes, and a central crotch portion. The diaper also has elastic gathering means disposed adjacent each of said side edges of the diaper in the crotch portion, and restraining means cooperating with the facing sheet to impart a generally arcuate cross section to the diaper in the crotch portion~ -According to a still further broad aspect of the ; present invention there is provided a disposable diaper including an absorbent pad having two straight side edges that 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 two side edges, front and back waistline portions and a central crotch portion. The diaper has elastic gathering means disposed adjacent each of the side edges of the diaper in the central crotch portion. The diaper further includes transverse restraining means cooperating with the facing sheet to prevent the diaper from 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 ~o. 4,050,462 and by Buell, in U.S. Patent No. 3,8609003.
Non-elastic disposable diapers which contain restrain-ing means which prevent the crotch area from fully opening to its unrestrained configuration are disclosed by Schaar, i UOS~ Patent ~o. 3,658,063, Karami, U.S. Patent ~o. 3,929,134, ~ and Mesek et alO, U.S. Patent ~o. 3,612,055.
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1~52701 -2a_ Brief Description of the Drawin~s 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 ` ~ 15 ~ 0 ~ CHIC 622 Fig. 4 is a cross-sectional view taken along line 4-4 of Fig. 3.
Description Of The Preferred Embodiments Fig. 1 illustrates one preferred embodiment of the invention as it would appear after all of the elements o~
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, the diaper 11 o~ 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 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 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 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 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 side edges 50, 52 of the diaper 11. The said dam is llS~l CHIC 622 formed by olding 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 bac~ing 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 115Z70~ 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 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 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 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 fibers, synthetic fibers or blends thereof. Typical facing sheets made of polyester type fibers may have a weight of about 0.75 ounces per square yard.
The facing may be smaller than the backing (as shown in 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 latter case, the elastic members may be secured above the inwardly folded side edges of the facing. In addition, facings may be made from non-apertured materials such as nonwoven sotropic webs or apertured polyolefin or polyester films having the desired moisture permeability.
In all of the aforementioned facings, the materials are ~ CHIC 622 1:~5;~70~
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 ~.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.
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i~5;~
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 suell in U.S. Patent No.
4,081,301 An alternative and preferred method of inserting the elastic gathering member is the following:
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 caus-ing a morphological change in the elastic material. Theproportion 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 in Kelly, Canadian Patent Application Serial No. 337,737, and assigned to the same assignee as this application. 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 !c,i llS~l CHIC 622 heating the film to a temperature of about 65C., up to about 82C.
It is preferred that the elastic strips or bands be 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 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 side edges, elastic gathering means adjacent to the central or crotch portion of the absorbent pad, and the 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 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 l~S~l 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.
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.
l~SZ701 -SUPPLEMENTARY DISCLOSURE
Since Applicant made the invention as described in the Principal Disclosure herein, Applicant has dis-covered certain improvements, and these improvements constitute the subject matter of the Supplementary Disclosure herein, The improvements are described in the following text together with the accompanying drawings in which:
Figure 5 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;
Figure 6 is a cross-sectional view taken along line 6-6 of Figure 5;
Figure 7 is a perspective view showing one embodiment of the disposable diaper of the invention; and Figure 8 is a cross-sectional view taken along line 8-8 of Figure 7.
Like numerals represent like parts in all Figures.
Turning to Figure 5, it is noted that although in Figure 1 the elastic strips 20 and 22 were illustrated as being in only the crotch area, Figure 5 illustrates these strips as extending the full length of the diaper.
In addition, while Figure 1 illustrates glue spots 36A, 36B, etc., Figure 5 illustrates glue lines 36B, 38B, 46B and 48B. As seen in Figure 8, the two longi-tudinal fold lines 42 and 44 run through the tux 54 and 56 at the bottoms thereof.
The facing sheet 12 was described in the Principal Disclosure as being made of an apertured non-woven fabric, it has been discovered that a non-apertured non-woven fabric may also be used. A preferred facing is a print bonded, carded web composed of 50 weight .
l~LSZ701 percent polyester staple fibers and 50 weight percent rayon staple fibers, with the bonded web weighing about 250 grains per square yard, ~n the Principal Disclosure, a preferred way of compressing the pad was described. This same pre-ferred way is used in the present disclosure with the following parameters: the pressure used to make the glue lines, on a 9 1/2 to 10-inch pad, which has a 4-inch ID air pressure cylinder, which presses the two rolls together, is of the order of 35 psig.
Having regards to the fastening of the elastic material, it will be appreciated that in accordance with the present embodiment, the elastic material is glued on the backing sheet for the entire length of the diaper, me glue lines or glue spots are considered to be transverse restraining means which cooperate with the facing sheet to prevent the diaper from opening to the flat or unrestrained configuration. me restraining means are called transverse because the restraining action acts in the transverse direction.
As mentioned in the Principal Disclosure, the location of the restraining means is an important feature of the invention, In one specific illustration of an infant size diaper having overall dimensions of about 15 inches by 11 1/2 inches, the glue lines 46 and 48 begin about 3/4 inch forward of the imaginary center line 41, and are each about 1/2 inch long and are about 4 inches in from the side edges 50, 52 of the diaper.
me fold lines 42, 44 are about 1-1/8 inches from the glue lines 46, 48, respectively.
The restrained facing sheet forms a pocket in the crotch area (shown as 58, in Figure 7), and therefore the diaper of this invention is more effective in holding fecal matter than is a diaper without the restraining -means, - -' ; - ' : ' - :
.
Another advantage shown by this diaper is more effective utilization of the entire absorbent pad, compared with hourglass shaped pads. In an hourglass pad, liquid must wick first longitudinally, and then laterally from the narrower crotch portion in order to reach the lateral extremities of the pad at the front and rear waistline ends. That is not necessary with the rectangular pad used in this diaper, wherein liquid flooding the crotch portion need only wick longitudinally to reach the extremities of the pad.
To illustrate the improved effective capacity discussed in the previous paragraph, a diaper of this invention was compared with a commercial shaped, gather-able diaper using the demand wettability tester described by Lichstein in U. S. Patent No. 3,952,584. The test measures the total amount of water absorbed by the sample from a point source--in this case, the center of the diaper.
The diaper of this invention weighed 67 grams The absorbent pad utilized a densified layer, as taught by Mesek et al in U, S. Patent No. 3,612,055, and wick-ing channels, as taught by Mesek in U. S. Patent No.
4,259,387.
The commercial diaper had an hourglass shaped absorbent pad and weighed 70 grams.
In the demand wettability test, the diaper of this invention absorbed 750 milliliters of water while the commercial diaper absorbed only 490 milliliters of water. The improved performance exhibited by the subject diaper is due in large part to the rectangular shape of the absorbent pad versus the hourglass shape of the pad in the commercial diaper. For reasons that were dis-cussed~above, the rectangular shape is more efficient in utilizing the absorbent capacity of the extremities of the pad. The densified layer and the wicking channels in - the diaper of this invention also contribute to the ability of the liquid to reach the extremities of the pad. But this is partially offset, however, by the fact that the densified layer has a lower liquid holding capa-city than the undensified portion of the absorbent pad.
In another test utilizing the same two diapers, a diaper is fastened in place on a life sized doll that is constructed so as to be able to void into the diaper to simulate actual use, The test liquid is 1.59% saline solution ~ontaining a red dye, The test solution is poured through the doll into the diaper in 150 milliliter incre-ments, with a twenty minute wait between increments, The test is stopped at the first indication of a leak of the liquid out of the diaper. The test is carried out with the doll being placed on an absorbent underpad of known weight, so that the amount of leaked liquid can be deter-mined, The diapers are also weighed before and after the test so that the amount of liquid absorbed by the diaper can be determined, The results of the test were as follows:
Weight of Weight of Absorbed Liquid Leaked Liquid Diaper of this invention 363,5 gms Trace (0,01 gm3 Commercial Diaper 343 gms 4.3 gms ,~
.
Claims (16)
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 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 for maintaining two tucks in said facing sheet in the crotch portion, each of said tucks being spaced respectively in-wardly 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 1 or 2 wherein each of said side edges of said diaper is folded inwardly to form two fold lines extending longitudinally the length of said diaper, wherein said facing sheet is adhesively joined to itself to form two tucks in the crotch portion, and wherein each tuck individually encompasses one of said fold lines.
6. The disposable diaper of claim 3 or 4 wherein each of said side edges of said diaper is folded inwardly to form two fold lines extending longitudinally the length of said diaper, wherein said facing sheet is adhesively joined to itself to form two tucks in the crotch portion, and wherein each tuck individually encompasses one of said fold lines.
7. The disposable diaper of claim 1 or 2 wherein the transverse restraining means are located slightly toward the front waistline portion of an imaginary trans-verse centerline of the diaper.
8. The disposable diaper of claim 3 or 4 wherein the transverse restraining means are located slightly toward the front waistline portion of an imaginary trans-verse centerline of the diaper.
9. The disposable diaper of claim 1 or 2 wherein each of said side edges of said diaper is folded inwardly to form two fold lines extending longitudinally the length of said diaper, wherein said facing sheet is adhesively joined to itself to form two tucks in the crotch portion, and wherein each tuck individually encompasses one of said fold lines, and wherein the transverse restraining means are located slightly toward the front waistline portion of an imaginary transverse centerline of the diaper.
10. The disposable diaper of claim 3 or 4 wherein each of said side edges of said diaper is folded inwardly to form two fold lines extending longitudinally the length of said diaper, wherein said facing sheet is adhesively joined to itself to form two tucks in the crotch portion, and wherein each tuck individually encompasses one of said fold lines, and wherein the transverse restraining means are located slightly toward the front waistline portion of an imaginary transverse centerline of the diaper.
11. 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 cooperating with said facing sheet to prevent the diaper from opening fully in the crotch portion to a flat configuration, and in use, said restraining means cooperating with said elastic gathering means to raise that portion of the absorbent pad between the restraining means and the side of the absorbent pad toward the wearer.
12. The disposable diaper of claim 11 wherein said transverse restraining means comprises adhesive means for maintaining two tucks in said facing sheet in the crotch portion, each of said tucks being spaced respectively in-wardly from the sides of said diaper.
13. The disposable diaper of claim 11 wherein said adhesive means comprises a plurality of individual glue spots.
14. The disposable diaper of claim 11 wherein said adhesive means comprises two glue lines.
15. The disposable diaper of claim 11 or 12 wherein each of said side edges of said diaper is folded inwardly to form two fold lines extending longitudinally the length of said diaper, wherein said facing sheet is adhesively joined to itself to form two tucks in the crotch portion, and wherein each tuck individually encompasses one of said fold lines.
16. The disposable diaper of claim 13 or 14 wherein each of said side edges of said diaper is folded inwardly to form two fold lines extending longitudinally the length of said diaper, wherein said faving sheet is adhesively joined to itself to form two tucks in the crotch portion, and wherein each tuck individually encompasses one of said fold lines.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US13438880A | 1980-03-27 | 1980-03-27 | |
| US134,388 | 1980-03-27 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1152701A true CA1152701A (en) | 1983-08-30 |
Family
ID=22463148
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000373787A Expired CA1152701A (en) | 1980-03-27 | 1981-03-25 | Gatherable, contoured, disposable diaper |
Country Status (10)
| Country | Link |
|---|---|
| JP (2) | JPS56148901A (en) |
| AR (1) | AR245588A1 (en) |
| AU (1) | AU528786B2 (en) |
| BR (1) | BR8101753A (en) |
| CA (1) | CA1152701A (en) |
| ES (1) | ES267163Y (en) |
| MX (1) | MX156552A (en) |
| NZ (1) | NZ196521A (en) |
| PT (1) | PT72739B (en) |
| ZA (1) | ZA812046B (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5509915A (en) | 1991-09-11 | 1996-04-23 | Kimberly-Clark Corporation | Thin absorbent article having rapid uptake of liquid |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| SE446055B (en) * | 1982-07-01 | 1986-08-11 | Landstingens Inkopscentral | CONTINENTAL PROTECTION OR BLOW WITH SIGNIFICANT RECTANGULAR FORM |
| CA1242301A (en) * | 1984-02-21 | 1988-09-27 | Patti J. Mokry | Shaped napkin with elasticized edges |
| AU568944B2 (en) * | 1984-08-02 | 1988-01-14 | Johnson & Johnson | Diaper with facing raised above absorbent pad |
| ES2061901T3 (en) * | 1988-12-20 | 1994-12-16 | Procter & Gamble | IMPROVED BRAGA. |
-
1981
- 1981-02-16 AU AU67323/81A patent/AU528786B2/en not_active Ceased
- 1981-03-16 MX MX18639281A patent/MX156552A/en unknown
- 1981-03-17 NZ NZ19652181A patent/NZ196521A/en unknown
- 1981-03-25 BR BR8101753A patent/BR8101753A/en unknown
- 1981-03-25 CA CA000373787A patent/CA1152701A/en not_active Expired
- 1981-03-26 JP JP4325481A patent/JPS56148901A/en active Pending
- 1981-03-26 AR AR28474981A patent/AR245588A1/en active
- 1981-03-26 ES ES1981267163U patent/ES267163Y/en not_active Expired
- 1981-03-26 ZA ZA00812046A patent/ZA812046B/en unknown
- 1981-03-26 PT PT7273981A patent/PT72739B/en unknown
-
1986
- 1986-06-19 JP JP9255786U patent/JPH0111681Y2/ja not_active Expired
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5509915A (en) | 1991-09-11 | 1996-04-23 | Kimberly-Clark Corporation | Thin absorbent article having rapid uptake of liquid |
Also Published As
| Publication number | Publication date |
|---|---|
| MX156552A (en) | 1988-09-09 |
| JPS56148901A (en) | 1981-11-18 |
| PT72739A (en) | 1981-04-01 |
| AR245588A1 (en) | 1994-02-28 |
| AU528786B2 (en) | 1983-05-12 |
| NZ196521A (en) | 1983-06-14 |
| AU6732381A (en) | 1981-10-01 |
| ES267163U (en) | 1983-03-01 |
| JPS6270105U (en) | 1987-05-02 |
| BR8101753A (en) | 1981-09-29 |
| ES267163Y (en) | 1984-07-01 |
| ZA812046B (en) | 1982-10-27 |
| JPH0111681Y2 (en) | 1989-04-06 |
| PT72739B (en) | 1982-11-11 |
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