Note: Descriptions are shown in the official language in which they were submitted.
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FORM FIT DIAPER WITH INSID~
SEAL AND THIcKFN~n CROTCH
AND METHOD.OF M~KI~G THF. SAME
Back~round of the Invention
The pre~erred disposable diaper construction
provides good ~luid re~ention without leakag~, the pad
does not shift or`disîntegrate i.n use and the diape.
does not feel uncomfortable on the skin. In addi~ion,
~he pre~erred diap~r does not cause excess we~ contact
wi~h the s'~in which tends to macerate the skin, reduc-
ing its ability to resist diaper rash or irritation~
Diapexs employi.ng elastic bands to hold the diaper
tightly against the ba~y~s legs helps stop side leak;lge.
The elastic bands, however, greatly increase the cost o
the diapers. U. S. patents 3,86~,003 and 4,050,462 are
illustrative of diaper constructions with elastic bands.
My U.S. p~tent 4,227,952 illustrates a method and appar-
atus for makin~ diapers with elastic bands.
Various d;aper constructions have also beendeveloped which employ hydrocolloidal matexial to in-
crease moisture absorbency. One of the draw~acks of
this construction has been t:he slippery) unc~mfox~a~le
feeli.ng of this material to the wearer of the diapers.
71~)4
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Diaper constructions have also been developed with water
impervious side seals to prevent leakage from the absorbent pad
along the side margins of the diaper. Sabee United States patent
3,386,442 discloses the use of separate plastic strips along the
side margins of the diaper to serve as a side seal. The plastic
strips of this type of construction, however, contact the skin and
cause chafing of the skin of the wearer of the diaper.
Summary of the Invention
The present invention provides a disposable diaper having
a generally rectangular outline and having an intermediate portion
of less width than the end portions to provide a form fitting
diaper crotch portion, said diaper comprising a moisture impervious
backing sheet, an absorbent pad on the backing, with the pad being
folded over upon itself in the crotch area to be of a thickness
greater than the thickness in the waistband portions to provide
increased absorbency in the crotch area, moisture impermeable
strips between said pad and said backing, said strips being folded
over the absorbent pad in the crotch area to lock the pad against
shifting, and a moisture permeable facing sheet having a shape
generally complementary to the backing sheet and sealed along its
edges to the backing sheet, and including spaced elastic bands
secured to one o said acing and backing sheets.
Various of the drawbacks and disadvantages of prior art
diapers are overcome. Leakage is mi nimi zed by providing an
auxiliary seal along the side edges of the pad, with the sealing
sheet located beneath a comfortable, porous facing sheet and
spaced inwardly from the side margins of the diaper. Positioning
the seal on the side edges of the pad under the facing sheet pre-
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vents it from coming in contact with the wearer's skin, thusavoiding chafing and irritation caused by contact of the plastic
film typically used for the water impervious parts of a diaper.
The side margins of the absorbent pads are free to open or expand
as they absorb the body fluids. Various absorbent materials having
different absorbent properties can be employed with this seal con-
struction. Examples are wood cellulose fibers and hydrocolloidal
absorbent materials. The side seals also hold the pad in place so
that it does not shift or disintegrate during use. This insures
that the pad is positively positioned as intended, to maximize pro-
tection.
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The absorbent pad assembly may have thicker
margins spac~d apart by a thinner central area which
will result in differential expansion of the margins to
a greater degxee than the central area when becoming
wet, which ~h~nces the seal against the baby's legs.
The thinner central area being more flexible will allow
the diaper to conform better to various body shapes.
This combined with the thicker side margins under an
expandable seal reduces to a m; n;m~lm the spill-over
which occurs during flooding conditions.
The side seal stxips are desirably per~orated
if they are wide to enable strike ~hrough o~ moisture
through the water impervious sealing strip portions
whi~h face ~he inan~ or user of the diaper. The per-
forated water impervious strips will preven~ Gon~actof the hydrocolloidal material with the user's skin ~nd
hence avoid the unpleasant feeling associated with con-
tact or such materials. An intermedia~e saaling sheet
may also be used whieh has per~oration~ at least in the
crotch area. This sheet will allow fast strike thxough
in the crotch area and allow wicking to the remainde~x
of the absorbent pad under the sealing sheet where it
cannot contact the skln of the wearer and become an
irritant. Moisture trapped against the skin can cause
irrita~ion.
The diaper and me~hQd of the in~antion can
employ ~70 spaced water impervious ribbons upon which
th~ absorbent pad is suppor~ed prior ~o assemb~y nf the
facing o~ the backing sheets~ The pad and ribbons are
sirnultaneously cu~ wit~ transverse cuts to fol~m the
,~
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foldable pad flaps. The ribbon and pad flaps are then
folded with the ribbon forming the edge side seals. The
ribbon is provided with adhesive prior to the cutting
and folding operation. The folded~ adhesively secured
ribbon also main~ains the folds of the absorbent pad.
Further objects and advantages of the inven-
~ion will be apparent from the disclosure.
Description of the Drawin~s
Fig. 1 is a plan view showing the method of
10 ~ki ng the diaper of the invention.
Fig. 2 is a side elevational view of the pro~
.edure in m~k;ng the diaper.
Fig. 3 is a sectional view along line 3--3 o~
~;1 ig r 1 ~
lS Fig. 4 is a view along line ~--4 of Fig. 1.
Fig. S is a view along line 5--5 o$ Fig. 1.
Fig. 6 is an enlarged perspective view with
parts broken away o the diaper of the in~ention.
Fig. 7 is a perspective ~iew o a modified
embodiment o the diaper.
Fig. 8 is a perspective view o~ a dîaper con-
s~ruction in which the side seal ribbons are pesorated
and ha~e incxeas~d absorbency zones under the si~e seal
ribbons.
Fig. 9 is ~ sec~ional view of a diaper simi-
lar ~ ~he diape~ shown in Fi~. 8 except the side seals
are made of orla piece cons~ru~tion with an auxiliary
pad in the cro~ch area.
Fig. 10 is a sectional view of a diaper con-
struc~ion with a perforated sealing sheet which is
,.,
sealingly connected to the top and bottom sheets at the
same general point along the margins.
Fig. 11 is a perspective view of the dia~er
shown in Fig. 10.
Fig. 12 is a diaper construction of a diaper
similar to that shown in Fig. 10 with the sealing sheet
sealed to the backing sheet at a different poin~ o~
contact for a form ~it diaper.
Fig. 13 is a perspective view with portions
removed of the diaper shown in Fig. 12.
Fig. 14 is a sectional view of a diaper con-
struc~lon in which the sealing sheet is tuc~ed around
beneath tne absorbent pad and side Inargins conta;ning
at~Eiliary absorbent strips.
Fig. lS is a perspective view of the diaper
cons~rucLion shown in Fig. 14.
Fig. 16 is a sectional view of a diaper con-
struction in -~hich the backing sheet i5 olded over
the facillg and sealing sheet~
Fig. 17 is a perspective view o~ the diaper
cons~ruction shown in Fig, 16.
Fig. 18 is a sectional view of a d~aper con-
~tru~tion having a one piece sealing sheet havin~ sides
folded aro~md and over the top of the absorbent pad.
~S Fig. 19 is ~ diape~ construction simi l~r to
Fig. 18 in which the folded over sides of thP sealing
sheet are~perforated.
Fig. Z0 is a sectional Vi8W of a diaper con-
s~ruction in which increas~d absorbent material is
located under the side mar~ins of the sealin~ sheet.
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Fig. 21 is a perspective view with parts re-
moved of the diaper construction shown in Fig. 20.
Fig. 22 is a diaper construction of a diaper
similar ~o Fig. 20, but o~ a foxm fit diaper.
Fig. 23 is a perspective view of the diaper
construction shown in Fig. 22.
Fig. 24 is a diaper construction similar to
the diaper shown in Figs. lO and 11 with increased
thick~ess of absorbent material along the side margins
in ~e crotch àrea.
Fig. 25 is a perspectiva view with parts
removed of the diaper shown in Fig. 24,
Fig. 26 shows a diaper cons~ructîon similar
to the diaper in Fig. 12 with increased absorbent
mater~al in the margins under the sealing sheat.
Fig. 27 is a perspective view with parts xe-
moved of the dîaper construction shown in Fig. 2Ç.
Fig. 28 is an e~larged ~ragmen~ary sectional
view of a diaper having ~he pad contAinin~ hydro~
colloidal material folded over under the side seal.
Fig. %9 is a view similar to Fig. 2~ with the
pad expanded upon absorption of moisture.
Fig. 30 is a diagrammatic perspective view o~
a modified embodimen~ of the method of ~qk7n~ diapers
wi~h ribbons which fonm ed~e seals.
Fig. 31 is a perspective view of a diapar
made in accordance with the meth~d o~ Fig. 30~
Fig. 32 is a fragmen~ary perspec~ive view of
a modified pad construction with a thin cen~ral we~
portion.
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Description of the Pra~erred EmbodimPnt
Although ~he disclosure hereof is de~ailed
and exaet to enable those skilled in ~he art to practice
the invention9 the physical embodiments herein disclosed
merely exemplify the invention which may be embodied in
other specific structure. The scope of the invention is
defined in the claims appended hereto.
The diaper of the invention is best described
by the me~hod of ~ki n~ one embodiment thereof.
Referring to Fig. 1, the initial step of
forming the diaper involves providi~g absorbent pad
material 10 and suppor~ing the pad 10 on continuous
spa~ed water impervious plas~ic ribbons 12 and 14
supplied from parent rolls 15. As illustrated in Fig.
2, ~n adhesive is applied to the ribbons 12, 14 by ~he
glu~ assembly 17 prior to application of the ribbons
~o the Fad. SubsequeIltly and s~nultaneously, t~e pad
an~ part o~ the ribbons are cut by ~uts 20, 22~ 24 and
26 formed by a Ic~ife assembly 2~ which may conver~e or
be at 90 to the machine dire~tion.
The cut por~ions of the pad and cut portions
o the ribbons are olded over by conventional folding
apparatus (no~ sho~) to for~n side seals for the diaper.
As illustrated ~n Fig. ~, the edges ~8 and 30 of the
absorbent pad can be f~lded over upon the mid portion
32 o~ the pad to provide increased absorbency. ThP
olded over rlbbons 1~ and 14 are preferably ad~esively
secured to the pad and backing to mainLain the folds
and lock the pad in place to preven~ .he pad from
shifting between the top and bottom sheets and pr~vent
12~7~04
- the pad from coming apart. Films having a high degree
o~ cling characteristics will secure itself to a com-
patible backing without ~he need of adhesives, some of
these films being high cling polyethylene or poly-
propylene, vinyldene chloride and various blends of
ethylene vinyl acetate (EVA) resins, but not limited
to these.
The folded over ribbons 12 and 14 may be ad-
hesively secured to the pad, facing or b~ck;ng to
ln further insure that the ~olds are maintained and the
pad locked in place to prevent the pad from shi~ing
between tha top and bottom shee~s and to preven~ the
pad from disentegrating.
Sllbsequent to the folding over of the pad
lS and ribbons, ~he pulp is CU~ o~f by a cut-of~ knife 39
and the top shPet 40 and the bot~om sheet 42 are applied
to the folded pad ~Fig. ~). Adh~sive is applied to
either the top or bottom sheet, or both~ by a glue ap-
plicator, suc~ as applicator 443 to seal the ed~es of
the ~op and bot~om shae~s and encapsula~e the pad. The
top and bo~.tom sheets are then llotchad by a cutting
assembly 45 so that ~hese shee~s are complementary in
sh3pe ~o the pad. The term~ "plastic ribbons", "water
impervious ribbons", "sealing strips'7 and "~ealing
sheet" arP used interchangeabl~ in this application.
The ~op or bo~om she~t can be provided with
spaced elastic ribbons 60, ~1 ~Fig~ ~) in the crotch
area by a method described in my pa~ent, or any other
technique. The elastic ribbons are adhesively applied
prior to assembly of both the ~op and botrom sheets.
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g
After th~ top and bottom sheets are secured
together, tabs ~re applied to complete the diaper.
Fig. 8 is illustrative of a diaper construc-
tion in which the ribbons 112 and 114 have inturned
sealing portions 116 and 118 which seal the side edges
of the pad 111 in the crotch area to prevent leakage.
The ribbons 112, 114 have perforated ~ones 117 in the
crotch area. Beneath the perforated zones 116 and 118
are incr~ased absorbency zon~s provided by either folded
over sides 120 of the pad 111~ auxilia~y pads or a
quantity of hydrocolloid material.
As used herein3 the term hydrocolloid material
means any water insoluble hydrocolloid in any of its
forms, whether i~ be a fiber, tape or powder or any
substance tha~ yields gels with water. This would in-
cl~lde but i~ not limited to the ~ollowing substances.
~a~ hydrolyzcd starch polyacrylonitrile eopdlymer H-
span, Produrt 35-A~100, Grain Processing Corp.,
Muscatine, Iowa, disclosed in U.S. pata~t No. 3~6~1,815;
(b) Product No. XD-8587.0IL, whi~h is cross-linked, Dow
Corning Chemical Co.~ Midland, Michigan; (c) Produrt No.
SGP 502S, General Mills Chemical, Inc. ~ Minneapolis,
Minn~sota; ~d) Product No. 7~-3710~ ~ational Starch and
Chemical Corp., New York, N.Y.; (e~ a hydrogel base
product, Carbowaxs a Trademark o~ Union Carbide Coxp~,
Charleston, West Virginia; ~f) ~ase-saponified starch-
polyacrylonitrile and graft copolymers, Unite~ States
D~partm2n~ of Agricul~ur2, Peoria, Illinois~ disclosed
in U S. paten~ ~o. 3,4~5,971; ~g~ Aqualon C and Aqualon
R wa~er insoluble sodium (arboxymethyl ceLlulose fibers
. ~.
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from Hexcules; (h~ absnrben~ starch ba~ed copolymer
Sstarcn-acrylonitrile)9 No. 35-A-100 polymer from Grain
Processing Co.rp.; and (i) polyacrylamide polymers,
such as XD-7~43.01 from Dow Chemical are all suitable
S and any of the wa~er insoluble absorbent polymers known
as "super slurpers" in ~he trade.
These produc~s are satis~a~tory ~or high
fluid retention in ~h~ crotch area while being sub-
jected to the nor~al flexing and pressures resulting
frorn movements of a wearer. Absorbent polymers are
also available in a ~i~m form and printed on or be-
tween two layers o~ abs~rbent tissue which can then be
cut to shape and placed in ~he most ef~c~ive area~
such a~ inside the seals at ~he sides of the absorbent
pad in the cro~ch area, othe- areas of the crotch area,
or tha t~tal crotch area. Elastic ba~ds may be attached
to the sides of the diaper in the ~ro~ch areaS at an
increase in cost, to furthe~ in~ure con~inement o
flooding to the absoxbents loca~ed in ~he crotch area.
Fluff-pulp, which is used in diapers~ has almost in-
stantaneous uptakP rate o~ liquids~ because only a small
percent o~ ~he. liquid is absorbed in the fiber, with the
remai.nter being heLd in ~he intPrstic~s o~ ~he fiber in
the pad. It îs extremely sensitive to pressure in that
applied pressures squeeze ~luids from ~he pad and into
body ~ontact whare it becomes an irritant~ Therefore,
increasing the bulk. in the sides or the absorbent pad
will h~lp instant.aneous a~sorption bu~ also subjects
these sides ~o greater pres.sures and a greater squeezing
action, causi.ng a grea~er amount of body f~uids to
12~0~L
escape from inside the edge seals. The use o an ab-
sorbent polymer in the edge seal zones overcomes this
problem. Sueh hydrocolloid materials have the capa-
bility of absorbing many times their weigh~ in liquids
and swell to form a gelatinous mass when wetted, and
will ~ot releas~ this l quid when subjected to pressures
from body movements~
Referring to Fig. 8, the sealing strips 112,
114 are preferably sealed to the backing sheet so that
the inturned portions 116, 118 of ~he sealing s~rips
lock the pad 111 against shifting be~waen the bottom or
backing sheet 109 and the ~acing sheet 127 (Fig. 9).
The perforated zones 117 permit moisture
penetration through the perforations or openings in
these zones and allow tha hydrocolloid material to
absorb the moisture. Tha perforated zones 117, how-
ever, will prevent co~ nication of the hydrocolloid
through the facing sheet which would provide a slip-
pery and gelatinous feeLing which is uncom~ortable
and undesirable. This undesirable feeling has been
a drawback in the past in tha u~se of hydrocolloids ~n
diapers.
Fig. 9 is a diaper construc~ion similar to
Fig. 8. However, the inturned edge seal portions 116
and 118 are the side margins of the one piece sealing
sheet 115 and are folded over an auxîliary pad 123.
Figs. 10 through 27 show various modified
embodiments using ~nterme~ia~e sealing sheets in between
the facing and backing shaets to assist in locking the
pad in place and to provide edge seals to prevent leak-
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- age fro~ the sides of the absorbent pad and to provide
an intermediate sealing sheet having perforations, slits
or valvular openings~ or being foraminous, to prevent
transfer of the hydrocolloid back through the facing
sheet. Figs. lO and 11 show a rectangular diaper con-
struction in which an intermediate water impervious
sealing sheet 140 has a perforated zone 142 in at least
the crotch area, as shown in Fig. ll, and the inter-
mediate sheet is sealed either by heat sealing or glue
along the margins 144 and 146 to both the ~acking sheet
150 and facing sheet 152. The sheet portions lSl pro-
vlde the seals for the absorbent pad 154.
Figs. 12 and 13 show an intermediate water
impervious sheet 1~0 with perfora~ions 152 in the
~5 crot~h area which is sealed alvng its la~eral edges
a~ 158, 160 at a point inwardly f~om the side edges of
the backing alld acing shPets, which are also sealed
aL 144 and 146. This type o~ seal is appropriate for
~he form fitting diaper.
Figs. 14 and 15 show a diaper construction
wi.th an intermedia~e sealing sheet 140 in which thP
lateral edges are folded around and tucked under the
absorbent pa~ by folds 162 and 164 and sealed to the
backing sheet intermediate the edges of the diaper at
166 and 168. Auxiliary pad strips 167 are provided.
In Figs. 16 arld 17j the intermediate sealing
sheet 140 is sealed to both the facing and backing
sh~ets. The backing sheet 150 has edges 171 and 173
whi~h are folded over the margins 175 of the facing
sheet 152.
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Fig. 18 shows an intermediate sealing sheet
140 having folds 176, 178 folded around and over on the
top of the pad 154. Fig. 19 is similar to Fig. 18, but
the inturned ends 180 and 182 are perforated at 184 in
the crotch area to permit strike through of fluid from
the top sheet.
Figs. 20 ~hrough 29 show diaper constructions
with increased pad thickness fonmed by either an extra
pad or hydrocolloidal material at the margins of the
diaper. When a hydrocolloid is used, swelling of this
material when e~posed to moisture tightens the diaper
against the body to enh~nçe the seal between the diaper
and the body to prevent spiLl-over or loss of body
~I.uids.
In Figs. 20 and 21, an intermediate sealing
sheet 14Q is wrapped around the absorbent pad 154.
Hydrocolloidal material 179 is located under thP flaps
176 and 178~ The diaper shown in Figs. 2~ and 23 is
similar to that shown in Fig. 20, but is a form ~it~ing
diaper. The flaps 176, 178 can be perforated in the
crotch.
T~e ~iaper construction illustra~ed in Figs~
24 and 25 in~ludes a sealing ~heet 140 with a perforated
zone 142 similar in construction to the dlaper show~
2S in ~igs. 10 and ll. Xowever, this diaper has increased
thit~kness o~ absorbent material along the side margin~
177, 17$ at least in ~he crotch area.
The diaper o~ Figs, 26 and 27 has an aux-
iliary pad in t;ne croteh area as well as the pad 111.
3~ It also includes a perfarated sPaling shnet 140.
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Fig. 2~ shows the differential expansion of the pad 1~4
in comparison with Fig. 28 along the edges after being
exposed to mois~ure as a resul~ or a larger quanti~y
of hydrocolloid at the longitudinal m~rgins of the
diaper rather than in the center of the diaper.
Fig. 30 bul~ pad material 200 is delivered
to a cut-off knire assembly 202 by conveyor 204. Dis-
creet lengths 206 of pad material are cut off by the
cut-off assembly 202 and deli~ered to a pair of spaced
ribbons 208 supplied from par~nt rolls 210. The backing
sheet 212 is supplied ~rom a paren~ roll 214. After the
pads 206 have been superimposed on the spaced ribbons
208, the ribbons are plow folded by plows 216 over the
side e~ges of the pad 206~ as shown in Fig. 31, to
provide edge seals. After ~he ribbons are ~olded, ~he
top sheet ~30 is applied over the ribbons and pad and
the ~iapers are subsequently cut~ from the wPb by a cut-
off assembly 232. In ~his method~ the ribbons are the
~ull leng~h o~ the diapQr rather ~han the lnegth o~ the
pulp or p~d as with ~he method illustrated in Fig. 1.
Fig. 32 illus~rates a pad construc~ion with
a thin conformable web sectiol~ 300 with thicker side
margins 302, 304. Th~ thin web section 300 collapses or
"necks down" to enable the diaper to better conform ~o
2~ the body and mai~tain a close fit during body movements.
he thick side margins 302 and 304 can includs a greater
concentration of hydrocolloidaL material than ~he
central cro~ch area.
3~
