US 3295526 A
Abstract available in
Claims available in
Description (OCR text may contain errors)
Jan. 3, 1967 E. sABr-:E 3,295,526
DISPOSABLE DIAPERS AND THE LIKE Filed Oct. 2l, 1964 2 Sheets-Sheet l Z ZZ Z3 I l e i I 'lill/Ill Illa/$111,111
afs E. AaL-E Jan. 3, 1967 v Filed Oct. 2l, 1964 E. sABEE 3,295,526
DISPOSABLE DIAERS AND THE LIKE 2 Sheets-Sheet E INNEN-ro@ Q/.5 E. .Sge-E f AM, Lwm
United States Patent O 3,295,526 DISPGSABLE DIAPERS AND THE LIKE Lois E. Sabee, 728 S. Summit St., Appleton, Wis. 54911 Filed Oct. 21, 1964, Ser. No. 405,548 Claims. (Cl. 128287)V Continuation-in-part of S.N. 232,391, filed Oct. 23, 1962 now abandoned.
This inventon relates to improvements in disposable diapers and the like which have an outer covering of liquid impervious material, but are otherwise made of liquid absorptive and liquid permeable materials.
The present -construction is applicable to disposable diapers for both children and adults, for use as bed pads or bath mats and similar articles, where liquids are to be absorbed and the used article is then discarded. It is preferred that a liquid absorbent filler be covered by a soft liquid permeable facing of relative high wet strength and by a liquid impervious cover which may be a thin flexible synthetic resin. Whenever the article is to be used as a diaper or is to be otherwise held adjacent the skin, it is desirable that the side or end portions coming in contact with the skin present a smooth padded surface or sof edge rather than having edges of the facing or the filler bearing against and irritating the skin. Either the facing or the cover may form the surface in contact with the skin.
For diapers in particular, it is desirable that the two ends be free from filler so that the facing and the 'cover form thin flexible end portions to serve as a waistband having a minimum of bulk. The corners of such waistband portions should be formed of a number of thicknesses for receiving pins for fastening the diaper in place. If macerated wood pulp or the like is used as filler, the batt may be embossed in spaced lines or in any other pattern to keep the batt together. A barrier sheet may be placed between the filler batt and the facing to prevent penetration thereof whenever the facing is very light. The barrier should be liquid permeable but need not be soft.
In the drawings:
FIG. 1 is a View of a diaper or the like from the liquid impervious side with a corner of the cover sheet broken away to show the extent of liquid absorbent filler and of facing sheet folded over the side portions of the filler.
FIG. 2 is a view of the facing sheet side and shows a waistband portion at one end of the diaper.
A FIG. 3 is an enlarged cross section of Vline 3-3 of FIG. l.
FIG. 4 is an enlarged cross section on line 4`4 of FIG. 1.
FIG. 5 is an enlarged cross section on the line 5-.5 of FIG. l. A
FIG. 6 is an enlarged cross sectional fragment of a modified article using one barrier sheet.
FIG. 7 is a view similar to FIG. 6of a second modification using a facing sheet and a cover sheet and two barrier sheets.
FIG. 8 is a view of the liquid permeable facing side of a diaper of FIGS. l-5, in which the facing wholly er1- closes the side edges of the filler and the longitudinal side margin strips of the diaper are folded inward over the facing to provide double thickness filler in such strips.
FIG. 9 is a cross section taken on the line 9 9 of FIG. 8.
FIG. l0 is a view similar to FIG. 9, but in which the permeable facing is reduced substantially in width for reducing cost of the most expensive element of the diaper.
FIG. l1 is a cross section taken on the line 11-11 of FIG. 8.
Y FIG. 12 is a view of the liquid permeable side of a diaper of FIGS. 1-5, in which the end portions which are 3,295,526 Patented Jan. 3, 1.967
free from the filler, are turned over the facing sheet of the diaper for attachment thereto, and
FIG. 13 is a cross section on the line 13-13 of FIG. l2.
Referring to the drawings by reference numerals, 10 designates a facing sheet of soft liquid permeable but high wet strength non-woven fabric on which is placed a batt 11 of layers or a mat of liquid absorbent filler. A cover 12 of thin and flexible liquid impervious material is Placed on the filler, the cover preferably being one of the relatively opaque synthetic resins. Side edge portions 15 of the facing 10 (or of the cover 12) are folded over the side edge portions of theiiller 11 to a substantial distance (e.g, 3A inch) and the cover 12 (or the facing 10) is cut to terminate short of the side edges of the diaper (by 1/2 or more). Soft and absorbent edge portions are thus provided along the side edges of the diaper which severally dene the leg openings when the diaper is in use. If the cover 12 forms part of the soft edge, the cover will be the surface in contact with the skin along side edge portions when the diaper is in use.
It will be seen that the filler is of uniform thickness all the way to its side edges (rather than thinning out toward the side edges), and that either the facing 10 (FIG. 3) or the cover 12 (FIG. 10) bear on and enclose the filler side edges. Thus rounded side edges are provided and there is the same quantity of filler per unit of diaper width all the way to the side edges to provide the maximum liquid absorption possible for a given width of diaper.
The side edge portions 16 of the cover 12 are fastened to the facing edge portions 15 as indicated at 17, by heat attachment when a thermoplastic resin is used such as polyethylene, or by use of a suitable adhesive. The cover 12 may have an over-all embossed pattern to reduce the surface smoothness and obtain a more nearly cloth-like texture to the touch.
At the ends of the diaper, the iiller11 terminates short of the ends 20 of the facing and the ends 21 of the cover and such ends are attached by dotted or full lines of adhesive indicated at 22 and 23. A third line 26 of adhesive fastens the cover 12 to the ller 11 across the ends of the diaper. A waistband is thus provided which is adapted to be joined by pins and in which the facing and cover are attached without having any filler between them to increase bulk and reduce resilience of the waistband. At the corners of the waistband (see FIG. 5), two thicknesses 15 and 15 of facing and one thickness 16 of cover material are obtained (or vice versa) which provides additional strength for pins. T he waistband is very thin and can be lapped or gathered to fit around the child without excessive bulk or difficulty in pinning.
The -attachment of the cover 12 to the facing edge portions 15 along the adhesive lines 17, penetrates into the filler 10 so that the filler is also attached to the facing. In addition to such attachment along the lines 17, attachment along the adhesive lines 26 joins the cover 12 to the filler 11 across the ends of the diaper so that the filler is respectively held to the facing and to the cover along both of the sides and the ends thereof.
Referring to FIGS. 6 and 7, the batt 30 is made from macerated wood pulp and a very thin facing sheet 10 or both a thin facing sheet and thin cover 12 are to be used. Pulp particles are likely to penetrate the facing and act as free lint or stick in and destroy smoothness of the facing. Hence a barrier sheet 31 is placed between the facing and batt or the cover and the batt or in both places. Such barrier 31 is also liquid permeable but need not be smooth and soft as it does not come in contact with the skin. The barrier sheet is extended between and is attached to the attached layers of facing and cover. Obviously the barrier may be co-extensive with the facing and the cover and Would then add one or two plies to the waistband for reinforcement where pinning is to be done.
It is well known in the paper converting industry that a batt of macerated wood pulp has varying moisture absorbing and conducting properties dependent on its density and thickness. When a diaper with a ller of uniform density and thickness is used, the rate of moisture conduction from a center point is substantially uniform in all directions. However, diapers are longer than their width and the effective (absorption) width of a diaper for a given size child can be increased only by some method of folding which increases the transverse absorption capacity. Further, diapers should be fitted snugly around the childslegs and waist but may be loose elsewhere. Also, under some circumstances, diapers must avoid presenting any liquid permeable material whatever where it can come in contact with the childs clothing or the person handling the child.
Referring to FIGS. 8 and 9, the facing edge portion 15 is overlaid by the cover edge portion 16 and the longitudinal margins of the diaper are folded to bring strips 35 and 36 inwardly so that all of the facing sheet 10 is turned toward the childs body when the diaper is in use, and only the cover 12 is exposed to the childs clothing or contact by another person when the diaper is in place. The folding provides double thickness about the legs with all of the absorbent material turned inward. The diaper can be drawn sufficiently tight around the legs to prevent moisture leakage from the side edges while being sufficiently loose in the body portions to be comfortable. The side strips 35, 36 add to the moisture absorptionY transverse capacity but the absorbent facing and filler are both wholly enclosed so there can be no moisture leakage from the side edges.
The rate of liquid absorption by the filler being substantially uniform, from any given point, liquid will 'spread from a center point A along radii of the same length until all of the liquid is absorbed or the nearer edges ofthe filler are reached. The diaper width being substantially less than the length as is shown by the circle B, if there is enough liquid present to penetrate to the side edges at the periphery of circle B, there will be substantial amounts of filler at the ends andin the corners of the diapers, which have not been used up to that time. To make use as uniformly as practical, of the absorption capacity of the diaper and avoid unabsorbed liquid collection in any areas, the diaper width should be increased by approximately two times the distance C (see FIG. 8) so that the effective circle of absorption is now shown at D. The increased absorptive capacity is provided by the folded over side strips 35, 36 and the increase in length of the circle radii toward the edges of the diaper now equals the length of radii to the filler ends. It will thus be seen that there is substantial increase in absorptive capacity, as well as other advantages, without substantial change in the proportions or the overall Width of the diaper as far as the user is concerned. Until the total filler width approaches the total filler length, there is little likelihood that any substantial amounts of moisture will be conducted to the ends of the filler.
It will be seen that the present article provides a disposable diaper with soft and liquid absorbentl filler enclosed within a soft, liquid permeable, high wet strength and, preferably, cloth-like facing, and a liquid impervious cover. lThe facing (or cover) is folded over the ller along the Vsides of the diaper and provides for contact of only the facing (or only the cover) with the skin, under usual conditions of use. Thus there may be a soft edge all around the leg openings of the diaper when it is in use. The filler is attached to the facing along the sides of the diaper and is attached to the cover over substantially its entire area so that the filler cannot shift relative to the cover. The ller terminates short of the ends of the facing and the cover so that only the facing and the cover form a waistband for the diaper when it is in use.
The four waistband corners have a double layer of facing for holding the pins. Where the facing is very thin or very porous, a barrier sheet is used to prevent migration of filler particles into or through this facing.
The diaper facing 10 costs nearly twice the cost of both the other two elements of the diaper. Hence it is desirable to reduce the area of facing used, and that effect can be obtained las shown in FIG. l0. The facing 10 is laid on the filler 11 so that bringing the side strips 35, 36 to the positions shown brings the filler 11 just to the side edges 18 of the facing. The cover 12 is then brought over the side strips 35, 36 and the side edges of the filler and down to the facing where it is attached.
The ends of the diaper are free from filler 11 as is shown in FIG. 4, and comprise only a facing portion 20 and a cover portion 21 (with double portions of facing at the corners as above described). However, when the side strips 35, 36 are folded inward and the ends thereof attached to the other end portions. The corners now have the number of plies shown in FIG. ll in which 10a, 10b and 10c are layers of facing and 12a, 12b are layers of cover. The corners where pinning is to be done thus have three layers of the facing and two full layers of the cover and the tensile and pin-tear strength are substan-` tially enhanced. The structure of FIG. l0 may also be made by laying down double thicknesses of filler along the longitudinal edges rather than folding the entire construction over as edge strips 35, 36. There will then be no plane of separation in the ller and the filler will be entirely homogenous.
When additional security is desired at the waistband,
the diaper may be made as shown in FIGS. 12 and 13 in which the end portions 20, 21 are first folded over and attachedto the facing 10fbefore the side strips 35,136 areY folded over and their'inwardly folded end portions laid on the balance of such end portions. The waistband length between the strips 35, 36 are now as shown in FIG. 13 and there is neither facing or filler coming to the ends of the diaper, through which there might be liquid seepage to the ends. Y combination of the side strip construction of FIG. 9 (or 10) and of FIG. 13. strength of the elements of the diaper, or of the several diaper constructions, no test was made of the FIG. 9`
The comparative table below gives the pin-tear strength of the non-woven facing alone, of the synthetic resin sheeting alone, and of thestructure .shown in FIGS.`15,V
11 and 13, in in. lbs., of a pin placed at the corners. The strength is measured with a pull both longitudinally and transversely of the individual sheets and ofthe entire diaper construction. The non-woven fabric is of the type made by forming a sheet of interlaced fibers of textile K length and interconnecting the fibers by a binder insoluble in the liquids to which the fabric is to be exposed. The non-woven fabric is thin and light and has a thickness of 3.6-4.2 mils. in the forrn used herein. If paper is used as the facing, its thickness can be reduced to 1.5 mils. The non-woven facing is not carded so that the difference in tear strength in different directions is not predictable. The cover material is preferably polyethylene sheeting of 1 mil. thickness. However such sheeting is embossed to provide a more cloth-like hand, which thickens the ma.- terial but does not add to the tear strength thereof.
The corners of the diaper are now aY However in comparing YtheY pin-tear The table shows that the facing and the cover individually have substantially greater pin-tear strength transversely than longitudinally. Such greater transverse strength is a fortunate circumstance because the greater stress is transversely when the diaper is put to use. The transverse strength of the corner construction of the diaper shown in FIGS. 15 is however much less than the sum of the strength of the individual elements of the facing and the cover, and the strength of such corners in a longitudinal direction is slightly greater than the sum of the strengths of the parts.
However when the structure of FIG. ll is used in which there are three layers of facing and two layers of cover, the pin-tear strength are nearly equal in both directions and are more than twice the values shown for the diaper of FIGS. 1-5. In view of the values of 3.9 and 3.67 lbs. obtained, it is immaterial that the transverse strength of FIG. ll structure is less than one-half that expected from the strengths of the individual elements shown for that construction, the strength being more than twice that of FIGS. 1-5 which has been found adequate.
When the structure of FIGS. 12 and 13 is used there are three layers of facing and three layers of cover at the corners, as well as two layers yof filler. The filler is not felted nor are the fibers joined in any way so that its individual strength is negligible. Again the transverse strength of the combined structure is less than the sum of the entire number of facing layers and cover layers but the longitudinal strength is nearly equal to such sum (4.2 lbs. as compared to 4.65 lbs.). In any case the strength in each direction in FIGS. 12 and 13 construction, is found to be ample to allow for the usual pinning of the diaper under any circumstances whatever.-
1. A substantially rectangular disposable diaper comprising a liquid permeable facing sheet, a liquid impervious cover sheet, and a liquid absorbent filler between the facing and cover, the facing sheet side margins extending `over and bearing against the filler side edges and having means connecting them about the filler side edges with the cover, the ends of the facing and cover extending beyond the ends of the filler for providing joined end portions including only the facing and cover, the filler being of substantially uniform density and thickness for its entire Width and length for providing substantially uniform liquid absorption throughout the entire filler, strips of the cover and filler longitudinal of and along the sides of the diaper being folded inwardly to increase the filler width available for liquid absorption in a given size diaper, end portions of the strips at the said end portions of the diaper being attached to adjacent end portions of the unfolded portionsV of the diaper.
2. The diaper of claim 1 in which the side strips are folded over the facing and attached thereto for holding the strips in given relation to the balance of the diaper.
3. The diaper of claim 1 in which the strips provide additional filler suiiicient to provide iller lof approximately the same cubic volume sidewise and lengthwise of the diaper.
4. The diaper of claim 1 in which strips longitudinal of the diaper side edges are folded inwardly and over the facing thereof, the end portions of the folded strips being severally attached to the adjacent end portions of the unfolded diaper portion.
5. A substantially rectangular disposable diaper comprising a liquid impervious cover sheet, a liquid absorbent iller terminating short of the side and end edges of the cover sheet, and a facing sheet terminating sidewise short of the side edges of the filler and extending lengthwise beyond the ends of the filler, the end portions of the cover and facing beyond the filler ends being coterminous and being joined across the width of the diaper, strips of the filler longitudinally of the side edges thereof being folded inwardly to approximately the side edges of the facing, the cover being folded along the sides thereof inwardly over the filler and joined along its side margins to the facing.
References Cited by the Examiner UNITED STATES PATENTS 1,192,439 Y 7/ 1916 Luellen 12S-286 2,696,819 12/ 1954 Lovekin 128-284 2,788,003 4/l957 Morin 12S- 284 2,829,647 4/ 1958 Dexter 128--284 2,916,037 12/ 1959 Hansen 12S-284 3,059,644 10/ 1962 Atkinson 12S-290 3,106,207 10/ 1963 Dudley 12S-290 3,180,335 4/1965 Duncan et al 128-287 3,211,147 10/ 1965 Pherson et al. 12S-284 FOREIGN PATENTS 632,111 12/1961 Canada.
RICHARD A. GAUDET, Primary Examiner.
CHARLES F. ROSENBAUM, Examiner.