Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
8~3~S~
This inven-tion relates -to a conEormable garment
such a~s for example, disposable diapers having discrete
elasticized areas by stretching a thermoplastic elastomeric
material, immobiiizing ~he s-tretched material in its extended
condition, heat treating selected spaced areas of the
s~retched elastomeric material while in the immobilized
extended condition so as to "kill" the elastic properties
of the heat treated zones, transferrin~ the immobilized
extended material toward a continuously moving web. In one
form of the invention, the thermoplastic elastomeric
material comprises a urethane based material, preferably
TUFTANE , a registered trademark of the manufacturer, B~F,
Goodrich General Products Company, Akron, Ohio.
The is a division of copending Canadian Patent
Application Serial No. 364,700, filed November 14, 1980.
Conventionally, conformable garments havin~ discrete
elasticized areas, have been formed in a wide variety of
ways and utilizing a wide variety of materials. One material
commonly employed as the elasticizing element has been
natural rubber, Buell U.S. Pat. No. 3,860,003 discloses
a disposable diaper formed of such material; while Buell
U.S. Pat~ No.
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\
s~
4,081,301 describes a process and ap2aratus for forr~ing such
a product. Similarly, Burger U.S~ Pat. No. 3,694,~15 ~nd
Woon et al. U.S. Pat. No. 4,050,462, both assigned to the
assignee of the present invention, disclose the use of natural
and/or synthetic rubber products to function as an elasticiziny
element.
Unfortunately, however, natural rubber imposes a number
of severe constraints on high speed manufacturing processes.
Thus, natural rubber is slmply not suitable for storage on
support spools because the xubber checks, assumes ~he shape
of the spool, tends to tangle , and binds in the inter~tices
between adjacent underlying loopsO Consequently, natural
rubber is normally supplied in boxes, with the continuous
rubber ribbon bPing festooned therein. This pla~es a severe
limitation on the quantity of material that can be supplied
withou~ requiring splicing; and, indeed, at conventional
production speeds it is yeneral ly necessary to splice such
boxes o~.natural rubber together on the order of every thir~y
minutes. In addition, since the rubber is festooned in boxes,
it tends to tangle and knot as it is removed from the boxes,
there~y causing breakage and~or si~nificant amounts of machine
down-time. Moreover, natural rubber normally re~uires talc or
other similar lubricants on its sur~aces~ and such materials
serivusly interfere with adhesive bonding echniquesr thereby '
necessitating a "detalcing" operation prior to adhesive bonding.
Natural rubber is generally rather dark in color and, there~ore,
when used in garmen~s such as disposable diapers having
relatively thin transparent or semi-transparent backing slleets
formed of p~lyethylene or the like, the xubber strips are
visible through such material and, t-herefore, detract fr~m
3--
th~ aestll,tic appearance of th~? product.
It has recently been proposed in publishe~ British appii-
cation ~o. Gs 2 010 68~ A, published July 4, 1979, and in
published ~ustralian apolication No. 43750J79, that unvulcani~ed
linear and/or radial block copolymers be utilized as the
elasticizing element in conformable garments such as diapers.
Such material permits re~oval of the elastic properties o~
the block copolymer up~n application of heat, ultrasonic,
or similar energy inducing means in a ~anner well known to
tho5e skilled in ~he art.
over the years, numerous techniques have been developed
in the prior art wherein the elastlc properties of an elastomeric
material are af~ected by the application of heat~ For example,
the aforesald Burger U.S. Pat. No. 3t694,~15 assigned to the
~5 assignee of the present invention contemplates freez~n~ of an
elastic material w~ile the material is in its stretched or
extended state so as to immobilize the material while i~ is
~ein~ applied to a gar~ent, and, thereafter9 thawlng the -
frozen material to restore its elasticityO In ~rexes et al~
British PatO NOD 783,726, the patentee coa~s a ~tretc~e~ elastic
material with a semi-rigid dressing to immobiliæe the stretched
elastic and, thereafter, applies heat to melt the dressing and
restore the elastic properties.
Mason U.S. Pat. No. 3,245~407, Althouse ~.S. Pa~. No.
3,6~9,917, and Koch U~S. Pat. No. 3,91~565 describe various
products and methods wherein selected materials are fastened
into a garment and subsequently heated in selected areas
thereof while in a contracted or non-stretched condition so
as to cause the heated areas to become shirred or elastic in
nature - i.e., a heat shrink process used to impart elasticity
51
to selected axeas of the garment.
However, despite all of the efforts that have
been made to provide a facile, economical process Eor
mass production of conformable garments such, for example,
as disposable diapers, problems have, prior to the advent
of the present invention, continued to plague the industry.
In addition to many of the problems described above with
regard to natural rubber - viz., difficulties in feed.ing
oontinu~us runs thereof without tangling, Xnotting and/or
breakage, difficulties in adhesive bonding as a result of
surface lubricants, kension uniformity, etc. - many of the
thermoplastic elastomeric materials that have been
suggested present similar, as well as somewhat different
problems. For example, since the elastic material is here
contemplated for usage in garments, it is important that
the material be characterized by its strength; not only
strength in usage, but also in the high speed manufacturing
processes employed. Where the material is to be hea-t
~reated to "kill" the elastic properties thereof in selected
discrete areas, it is important that the heated material
possess sufficient strength as to resist breakage,
particularly when the heated material is being worked on
in a high speed continuous product.ion process. Color
characteristics and adhesive bonding propert.ies have
continued to present problems.
In one of its aspects, i-t is an object of the
invention to form conformable garments such, for example,
as disposable diapers having separate elasticized areas,
yet wherein both the elasticized areas and the non-elastic
areas of the garment can be formed compatibly with high
speed production processes - e.~., processes wherein the
garment components are being worked on at speeds suffici.ent
to produce in excess of 250 diapers per minute.
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~38135~
SUMMARY OF THE IMVENTION
According to the presen-t invention thi.s provided
a conformable garment having at least one discrete
elasticized area and including, in combination, a garment
component in a thermoplastic elastomeric urethane ribbon
adhesively bonded -to the component, the ribbon ha~iny at
least one heat treated portion thereof whereby the
elastic properties of the portion are destroyed relative
to the component while the remaining portion of the ribbon
retains its elastic properties for elasticizing at least
one discrete area of the garment component.
One form of the invention resides in a disposable,
unitary and generally elongate diaper having a substantially
planar waistband section at each end and a narrow
substantially non-planar cro-tch section disposed between
the ends and wherein the diaper i5 comprised.of a porous
facing sheet, fluid-impervious backing sheet and an
absorbent batt disposed between the sheets and in which
the peripheries of the facing and backing sheets adjacent
the batt are joined to each other. Elastically extendable
means if provided for longitudinally contracting the narrow
crotch section over its entire width, the contraction
being obtained by having at least one each of the
elastically extendible means secured while in extended
condition to at least one of the facing sheets of the
backing sheet along the entire length of the adjacent each
edge of the crotch section, the elastically extendible
means including a thermoplastic elastomeric urethane material
whereby when the elastically extendible means are relaxed
and contract and bondecL together diaper structure is
elasticized across the entire wid-th of the crotch section.
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:~886)5~L
DESCRIPTION OE` T~IE DRAWINGS
These and other objects and advantages of the
present invention will become more readily apparent upon
reading the following detailed description and upon reference
elastically extendible members to a continuous web which
forms part of a garment during a continuous high speed
production operation so as to elasticize discrete areas of
the web and, thus, of the garment to be formed, with the
elasticized discrete areas here being shown in the fully
extended condition as normally occupied during the
manfacturing process;
FIG. 6 is a side elevational view, partly in
section and partly in diagrammatic form, here illustrating
details of an ex mplary high speed continuous production
system ernbodying features which is suitable or applying
elastically extendible continuous ribbons in an extended
! state to a continuous web and wherein provision is made
for destroying the elastic character of the elastically
extendible ribbons in selected discrete areas so that only
other selected discrete areas of the continuous web are
elasticized;
FIG. 7 is a plan view partly in secti.on and taken
substantially along the line 7-7 in FIG. 6, here illustrating
details.of the elastic ribbon supply system utilized
with the apparatus shown in FIG. 6;
FIG. 8 is a sectional view similar to FIG. 3, but
he.re iliustrating a slightly modified disposable diaper
product which can be made in accordance with the present
invention; and,
FIG. 9 is a plan view of a partially completed
disposable diaper product, here illustrating an alternative
embodiment of the invention wherein the selectively
ms j~
:~L8~ 5~
elasticized areas of the continuous web can be formed with
a shaped con-Eiguration so as to improve the conformability
of the finished diaper product.
While the invention is susceptible of various
modifi.cations and alternative forms, specific embodiments
thereof have been
!
-- 8 --
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shown by way of example in th~ drawings and will herein he
descrlb~d in detail. It should b~ understood, howe~er, that it
is not intended to limit the invention to the particular for~s
disclosed, but, on the contrary, the intention is to cover all
modi'icztions, equivalents and alternatives fallin~ wi-thin t.he
spirit and scope of the in~ention as expressed in the appended
claims.
DETAILED DESCRIPTION
Refer~ing ~irst to FIGS~ 1 and 3, ~he present invention
has been illustrated in conne~ction wit~ the formation of a
conforma~le ga~nent which is here shown as a disposable
. diaper, generally indicated a~ ~O. Although the exemplary
diapex 20 is her~. illustrated in the ~or~ of a finishea
product severed from ~he continuous web of products ~ade
in a high speed continuous production operation, it has, fox
purposes of facilltating a complete understanding of the
invention, nevertheles~ been shown in the stretched or fully
extended position that the product would normally occupy
just prior to being severed from the continuous web upon
completion cf the manufacturing process.
Xn keeping with the present inventionr the illustrative
diaper 20 is of elongate generally "I~' shape, and ~ncludes a
~luid permeable ~acing sheet 21, a fluid impervious backing
sh~et 22, and a hiyhly absorbent batt 24 san~wiched bet~een
the fac.iny and backing sheets 21, 22 respecti~ely.
The specific components used to form the exemplary
diaper may be any of the types commonly used for such purposes.
For example, the fluid pervious facing sheet may be any so~t~
_.g_
5~
~lexil~ ous sheet which permits the nass~ge of fluids
therethrou~h including h~drophobic or hydrophilic non-~Joven
webs, wet stren~th papers, spunwoven filament sheets, and the
like. A particularly suitable sheet is one made of spunwoven
polypropylene filaments with spot embossing, and preferably
with a perf~rated surface or suitable surfactant treatment to
aid fluid transfer. The fluid impermeable backing sheet 22 is
preferably a thi~ plastic film such as poly~thyl~ne, polypro-
pylene, polyvinylchloride, or the like and would g~nerally be
10 on the order of one mil in thickness. The sheet is preferabl~
vpaque with an embossed or matte surface.
As disclosed in greater detail in the aoresaia Wovn
et alO V.,S. Pat. No., 4,050,462~, a suitable material for the
absorbent batt 24 used in ~he exemplary diaper is ~n air-formea
15 batt of wood pulp :Eibers commonly known as "fluff"" In one
prefexred example described in the aforesaid Woon et al. patent,
th~ fluff ~att weighed about n .286 grams~sq. i~o of area in its
unconstricted condition as well as in ~he planar sections o~
the batt when t~e othex ~ortions of the diapers are constricted,
and about 0.32 grams~s~. in. in the constxicted crotch section
of the batt. It is preferred that the effective weig~t o~ ~he
absorbent material in the constricted crotch area be at least
15~ greater per unit area than the weight of the absorbent
material in the planar a~ea. The thickness of the same fluf~
batt in unconstri~ted condition was measured at about 0.755n
and, in ¢onstricted condition at about 1.27:'. The ~onstricted
batt~ therefore, had ~ore efective thickness in the constricted
area. Depending on the size diaper bein~ selected, the startin~
flat or planar weight and thickness may be ~uitably varied,
i.e., thinner for the 5maller sizes, thicker for the largex
--10--
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sizcs. ~ther absorbent m~terials, alone or in cornbination and
includi,ng ~ebs of carded or air-laid textile fibers, rnultiple
plys of creped cellulose ~adding, various super absorbent
materials, synthetic foa~ sheets or the like ~ay also be used.
The batt may also be slightly compressed or embossed in selected
areas as desired.
The exemplary diapex shown in FIG. 1 is divided into
waistban~ sections 25 and ~6 at each end and a central narrowed-
down crotch section 28 disposed between the waistband sections.
10 ' During use, waistband ~ection 25 would normally be disposed a~
the back of the in~ant and may from time to tlme be referred to
hexein as the back portion of the diaper~ while section 26
would normally be disposed at ~he front and may f~om time to
time be referred to herein as the fron~ portion of ~hP diaper.
Conventional pxessure sensitive tapes 29 are ~ttached to th~
backin~ sheet 22 near the edges of waistband sec~ion 25 for
~astening ~urposes, although other suitable fa$tening means may
be employe~. Such tapes are usually attached near the bac~
portion of the diaper. One sur~ace of ab50rbent batt 24 is
bonded to backing sheet 22 and/or to facing sheet 21 in at
least the crotch section 28. Preferably, the absor~ent batt is
bonded to backing sheet 22 in the crotch section~ Such bonding
may be done by the use of strips o~ double~~aced pxessure
sensitive tape, by strips of hot melt or pressure sensitive
adhesive, by overall or patterned heat sealing, by a pri~ted
pattern of adhesives, or the like. One desirable type of
adhesive is an atactic polyprop~lene based ho~ melt adhesive of
the type known as A337S manufactured by Eastman Chemical Co. of
Xin~sport, Tennessee. Generally, attachment should be such
that when the sheet to which the batt 24 is bonded is constricted
q35~
in its l~ngitudin~1 direction by elastic means 30 disposed n~ar
the batt edges, the batt will also be constricted and con~oluted
thereby.
Each edge of the diaper in the narrow crotch section 28 is
S provided with an elongate elastic means 30 secured in extended
condition to backing sheet 22 and/or to facing sheet 21 along
the entire ~ength of the crotch section 28. In keeping wîth
the presen-t invention, the ~ree ends 31 o~ the elastic ~eans 30
positioned in the waistband sections 25~ 26 are preferably
treated in such a manner as to destroy their elastic proper~ies
relative to the backins sheet ~, Such free ends 31 o~ the
elastic means 30 may~ if desixed, be s~cured to the backing
sheet 22 in the 5ame manner as the el stic means-30O
It should be und~rstood t~at when it i~ s~ated herein
that discre~e ~reas of an elastic ribbon or ~ape are treated
to destroy or "killn the elastic properties of t~e ribbon in
such areas, it is meant simply that t~e elastic properties in
those txeated discre~e areas are altered so that the~ no longer
exhibit elas ic pxoperties relative ~o their envixonment. ~ox
example, were the treated free end 31 of the elastic ribbon
30 shown in ~IG. 1 to be removed from the hacking sheet 22,
such free end would stlll exhibit elastic properties and would
~till be capable o~ being stretched. ~owevex, when released
it would return to the length depicted in ~IG. lo and not to
its original length prior to treatment. It is in this sense
tllat the elastic properties o~ the portions 31 are destroyed .
: or l'killed"~ since such portions will not serve to elasticize
the garment.
As previously indicated, the elastic means 30 is fully
3~3 stretched and under tellsion only during the manu~acturing
--12--
~8~51
proc~s.~ en it e~ists as a continuous len~th for co~ve~ienc~
in the process. The diaper is shown in its fully extended
condition in FIG. 1, a condition which it would normally occupy
only during the manufacturing process when a series of diapers
are attached to each other in the form of a cor.tinuous strip.
~hen this continuous strip is cut into individual diapers, the
elastic means 30 is thus relieved of its tension and contracts
frorn its fully extended condition, causin~ the crotch section
28 of the diaper to contract in the elasticized area as shown
in FIGS. 2 and 4. As indicated therein, waistband sections 25
and 26 are not constricted an~ remain substantially ~lat ox
planar because the end portions 31 of the ~lastic means 30 do
', not exhibit elastic characteristics xelative to ~he underlying -
.~ .
backing sheet 22 and, consequently, there is an absence of a
tensioned elastic member in those sections. When the relatively
narrow crotch section 28 is constricted by the contra~ted elastic
means 30 at each ed~e, the c,rotch section develops a multi-
plicity of gross transv~rse rugosities 32. Stated another way~
crotch section 28 i5 reduced in len~th but still co,ntains the
same amount of absorbent material. Accordingly~ the a~sorbent
batt 24 in the crotch area 2~ is made effectively thicker because
of the adjoining hills and valle~s ~f which the transverse
rugosities 32 axe comprised and, therefore, will have more
absorbent capacity per unit a~ea than a batt ~ the same
original thickness has in its initial planar form.
In addition to making the diaper 20 effectively more
absorbent in the crotch area 28J the cushionins effect of the
pa~ element forming the rugosities 32 serves to relieve some
of the pressure of the tensioned elastic mean.s 30 where it
presses the diaper into contact with the infant's skin
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ll~B05i
~hen the diaper is h~orn. Accordingly, even though the elastic
means 30 will be under tension in the crotch ar~a 2~ due to
its being partially stretched out when the diaper is applied
to the child, the transverse rugosities 32 remaining in the
absorb~nt pad act as cushions and tend t~ reduce the possibilitv
of the elastic indenting or marking the skin. Such indentation
or marking is more likely to happen when the tensioned elastic
means 30 is paxt of a thin flexible flap as com~only emplo~ed
in the prior art, thus permittin~ more intimate contact with
the s~inO
As heretofore indicated~ garmen~s having discrete elastic
areas are well known in the art, and many different types ~f
:. . such gaxments have been described in issued patents. ~or example,
in the a~oresaid 13uell Pat. No. 3,860,003, the paten~ee employs
elastic tapes formed of natural rubber. In the a~oresaid
published British application No. GB 2 010 682 A and published
Australian application No. 43750/79, the applic~nts describe
the use of thermoplastic elastomeric members comprising and/or
cont~i~; ng unvulcanized linear or radial bloc~ copolymers o~
the general configuration A B-A and of ~he type described
in Zelinski et al. ~.S. Pat. No. 3,281,383.
In accordance with the present inYention, however~ improved
garments having discrete elasticized areas such, for example,
as the disposable diaper 20 described above in conn~ction w~th
FIGS. 1-4, are formed with thermoplastic elastomeric ribbons or
tapes 30 having a urethane base and, more specifically, from
TUFTANE ~ and~ preferably, from TUFTANE ~ Type TF~410g an elasto-
meric material which has proven to provide tremendous advantages
for use in, for example, disposable diapers ~0, especially when
compared ~o products ~mploying, for example, elastic bands
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1~88(~S~
formed of nat~lr~l rubber or ei.ther linear or radial block
copolymers. I
Thus, when comparing TUFT~NE~ with natur~l rubber,
TUFT~NE~ has been Eound to have more uniform tension properties
and to be thinner, softer and more flexible. ~ruFTANE~ can
further be stored on spools in the manner more fully described
in the copending i~anadian application of Morris et al.,
Serial No. 362,912, filed October 21,. 1~0, and supplied from
such spools, whereas natural rubber generally must be festooned
in boxes since, when efforts are made to spool natural rubber,
the rubber tends to check, to assume the shape of the spool,
to tangle, and to bind within the interstices between adjacent
ones of the underlying loops on the spool. TUFT~NE~, on the .-
other hand, because it can be spooled, substan~ially e1im;nates
tangles, knots and breaks in high speed production processes,
and can be stored on spools in sufficient quantities which
permit operation of production runs up to and in excess o~
eight hours without the need to splice the TUFTANE~ bands;
whereas, estooned natural rubber generally requires splicing
1 20 between successive boxes every thirty or so minutes ak normal
production speeds. TUFT~NE~ further permits of destruction
of its elastic properties relative to its environment, whereas
natural rubber does not. Because TUFTANE~ can be obtained
in colorless form, those products such as disposable diapers
which commonly employ a relatively thin transparent or semi-
transparent backing sheet 22 formed of polyethylene or the
like, have a much more pleasing aesthetic appearance.
:~ When contrasted with other thermoplastic elastomeric
~atarials such, for example, as block cop~lymers, TUFTANE~
has proven to have similar adYantages. Thus, it permits ease and
- 15 -
pC/f,~.~
si~.plicity of process control since the elastic properties can
be effectively 100% "killed" relative to the environ~ent over a
relatively h~ide range of temperatures and, further, ~UFTA~E ~
is ver- strong and does not tend to break or tear easily either
in the overall high speed production process utilized ox in the
heat treating "kill n process used to destroy its elastic pro-
perties relative to the environ~ent in selected discrete areas.
TUFTA`~E further exhibits excellent adhesive bondiny properties
and possesses a high coefficient of fric~ion which is essential
to prevent slippage o the elastic ribbons during the~ manufacturing
process, especially when intermittent spaced discrete areas of
the ribbon are suhjected to heat to nkill" the elas~ic properties
of the ribbon in such areas. As in the case of natural rubber~
the availability of colorless TUFTANE~ r~--;ns a distinct
advantage over many other types of thermoplastic ela~tomers
which are not color7ess and~ therefore, whic~ tend to detract
from the aesthetlc appearance of products such as disposable
diapers.
Thus, referring to FIGSo 1-4, and in accordance with the
present invention, the elastic means 30 comprises a strip or
~ibbon o~ TUFTANE~ , preferably on the order o~ 1.5 mils in
thickness and on the order 1/2" in width, wherein the end
portions 31 have been heated so as to destroy or "killl' the
elastic properties of the ri~bon relative to the faoing andlor
backing shee~s 21, 22 to which ~he xibbon has been attached. As
a consequence, when the individual diapers 20 are severed from
the continuous web of interconnected diapers ~ormed in a manu-
facturing process, the central poxtions o the TUFTAN~ ribbons
which are co-extensive with the crotch section 28 and which
have not been subjected to sufficient heat to nkil 1~ Ox otherwise
deleteriously aff~ct the elastic properties thereo~ tend to
~16-
305~
contra~t, th-~s forr~iny the transverse ~ugosities 32 in the
diaper as best illustrated in FIGS. 2 and 4; wh~reas, the
waistband portions 25, 26 of th~ diaper 20 remain substantially
plan~r and are not contracted since the end portions 31 of the
5 TUFTA~E~ ribbon have had the elastic properties thereo~
effectively "killed" in the manufacturing process by the
application of heat thereto.
In accordance with another of the importdnt aspects oE the
present invention, provision is made for affixing t~ermoplastic
elastomeric strips on selected separate discrete areas of a
continuous web sui~able for use as a portion of a conformable
~arment on a high speed, continuous~ production basis. In the
i preferred form of the invention, methods and apparatus are
provided for a~fixing one or ~ore TVFTANE~ ribbons 30 to a
continuous web or sheet of material suitable for use as the
backing sheets 22 for a series of interconnected diapers whexe
the continuous web is moving at a relatively high speed ~ e.~.,
speeds sufficient to produce in exc2ss of ~50 diapers per minute--
yet, where the TUFTANE~ ribbons ~0, although also movin~ at the
~0 same xelatively high speed, ar~ immobilized xelative to a ~urface
moving at that speed and having at least one heated "kill'l zone
and at least one unheated "no-kill" ~one; whereby the elastic
properties of the ribbon are destroyed in the heated ~ zone
but remain unaltered in the unheated "no-kill" zone. In the
exemplary for~ of the invention, the elastic properties of ~he
TUFTANE~ ribbons 30 are selectivel~ ~Ikilled~ in spaced discrete
areas just prior to being affixed to the continuous web.
To accomplish the foregoing objectives of the invention;
and as illustrated diagrammaticall~ in ~IG. 5, a system, generally
indicated at 40, is provided having a supply standl generally
--17~
-
i~di~ated at 41, fo.r l~v~l-woun~ spools 42, 44 of a suitz~le
thermoplastic elastomexic material, pref~rably T~FT~7EG ,
level-wound thereon in the form of continuous TUFTANE~ ribbons
30, 30'. The TUFTANE~ ribbons 30, 30' are fed from the supply
stand 41 through a selective heat treating zvne, gcner211y
indicated at 45, and then to an axea, generally indicated zt
46, where the ribbons 30, 30' are ~f~ixed to a continuous ~eb
48 m~ving at the selected high production speed--e.g~, at a
speed sufficient to produce in excess of 250 diapers per minute.
lû The web 48 may be fed from any suitable ~onventional source
~not shown~ to and throu~h the area 4~ where the TUFTA~E~
ribbons 30~ 30' ar~ affixed; an~ to further con~entional web
processing areas (not shown in FIGD 5, but located downstream
as indicated ~y arr~w 49 and as hereinafter described~ where
the comp~site web and TUFTANE~ may be assembled with a series
~ absorbent batts 24 (FXG., 1) and a continuous web defining
intarconnected fluid permeable faci~g shPets 21 such as shown
! in FIG. 1, to form a continuous sandwich (of the type shown in
FIGS~ 1 and 3~ suitable for forming a plurality of disposable
diapers upon being severed trans~erse~y of the sandwich in any
conYentional manner ~not shown).
As here shown, the spools 42, 44 holdin~ continuous
TUFTANE~ rlbbons 30~ 30~, respec~ively, are pre~erably level-
wound in the mannex described in greater detail in the aforesai
application of Morris et al., Ser. ~o. 362,912 , ~iled October 21
1980.. Each of such spools is capable of holding a sufficient
quantity vf TI~FTANE~ ribbon approximately 1.5 mils thic~; and
on the order of 1/2 in widt~ to supply a production line
operating at a ~peed sufficient to produc~ in excess of 250
-18-
8~5~
diap~rs ~er minute for up to eight hours. Thus, the ribhon 30
carriec bi, Cor e~:a~ple, spool 42 is unwound therefrom and
passed through a nip 50 define hy an idler roll 51 and a
driven roll S2 and, thereafter, ahout a second idler roll 54.
To ensure that the ribbon 30 is properly registered with the
web 48, the ribbon 30 is twisted 90 after passing around idler
roll 54, and is fed between a pair of spaced~ upright guide
rollers 565 58. Roller 58 is aligned in the machine direction
with a pulley or sprocket 59 af~ixed to a magnetic powered
tension read-out rolle~ ~0. During transit from guide roller
58 to sprocket 59, the ribbon is retwisted 90 so as to pass
smoothly around the sprocket S9O In precisely the same fashion,
the TUFTANE~ xibbon 30' fxom spool 44 is fed throu~h a nip 50
defined by an idl~r roll 51' and a driven roll 52', around a
secona idlex roll 54' J through a pair of upright guide xollers
56', 58'~ and around a second sprocket 59' carried ~y tension
read-out roller 60'.
In order to "kill n the elastic properties of the T~FTANE~
ribbons 30~ 30' in selected, spaced discrete areas in accordance
with the present inventiont the ribbons 30, 30~ are fed in
parallel about a suitable roll 61 and about the periphery of a
driven roll 62 having a peripheral surface defining alternate
heated ~ones 64 and non-heated zones 65. Thus, the driven roll
62 defines a hi~h speed moving surface having a pair of heated
"kill" zones 64 alternating with a pair of unheated "no-kill"
zones 65~ The ribbons 30, 30~ are in intimate face-to-face
contact with the roll 62 throughout approximately 2?~ o the
surface of the roll. In order to ensure that there is no
relative slippage between the driven roll 62 and the ribbons
30, 30l~ the unheated ~ones 65 ~re prefera~ly formed of an
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inher~rltly non-slip m~teri~l such, for exar,lr~le, zs so~t silicone
foam rubber. Immobilization of the ribbons 30, 30' relative to
the driven roll 62 is essential in order to ensure th~t the
alternate areas 30, 31' of the ribbons do not slip as a result
of the elastic properties which are retained in those areas of
the ribbons overlying the unheated "no-kill" zones 65.
While the exemplary syste~ 40 shown diagrammatically in
FIG. 5 has been illustrated as including heated zones 64 which
extend acxoss the full width o~ the roll 62, it is not necessary
to heat that extensive a sur~ace area of the roll. Rathery it
is only necessary to heat a pair of relatively narrow circum~
ferential band~ somewhat wider than the ribbons 30, 30' so as
~o ri nir; ze the need to provide per~ect registration between
the ribbons 30, 30' and narrow heated circumferential bands.
lS Heating only narrow circumferential bands rather than the full
width of roll 6~ in the heated zones 64 serves to minir~ize heat
transfer to adjacent components vf the apparatus such, for
example, as the roll 61 previously described or a driven take-off
roll 66.
Following selective heat treatment of spaced dlscrete
areas of the immobilized elastic ribbons 30, 30', t~le ribbons
are transf~rred to a take-off roll 66 which also sexves as a
chill roll. To insure that ~he ribbons 30, 30l remain îmmobi-
lized until bonded to the continuous web 48, the take-oEf or
chill roll 66 is provided with a high-friction, non-slip surface
such, for example, as a surface formed of soft silicone fo~n
rubber. The chill roll 66 serves to prevent heat build-up in
the unheated ~ones 65 of roll 62, to cool the heat treated
portions of the ribbons 3~, 30', and to prevent ox mini~ize
heat transfer to those portions of the sys~.em used to convey
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the COntillUOUs ~b .8. A fille bead of adhesive is preferablv
applie~ to th~ e~;posed surfaces of the ribbons 30, 30' as they
are carried about roll 66 in immobilized fashion by any suit2ble
adhesive applying means (not shown in FIG~ 5, but hereinafter
described in greater detail). After application of adhesive
thereto, the still immobilized ribbons enter a nip 68 defined
by roll ~6 and an idler roll 69.
To per~it adhesive bondin~ of the xibbons 30, 30' to the
continuous web 48, the web is passed around idler roll 70,
through the nip 68 de~ined by idler roll 69 and roll 66~ and
then around idler rolls 71J 72 and downstream (not shown in
FXG~ 5) on the production line where the web is formed in~o a
sandwich such as shown in FIG~ 3 comprising outer or fluid
impermeable backing ~he~ts ~2 (~ormed from web ~8), a plurali~y
of spaced absorben~ batts 24~ and a second continuous web
defining the fluid permeable facing 5heets 21. As ~he web 4B
enters the nip 68, it comes into contact with the adhesively
coated im~obilized ribbons 30, 30l which are carried ~y roll 66
and is securely bonded thereto by pressure applied by idler
roll 6~. As a consequence, the web 48 and elastic ribbons 30,
30' together with their alternating hea~ treated non elastic
portions 31, 31l exit from the idler rvll 59 and are transported
as a composite unit with the elastic portions 30, 30' still
fully extended about the idler rolls 71 and 72 for further
processing in the manner described above~ When the continuous
diaper sandwich has been completely formed~ the sandwich is.
severed transversely through the mid-points vf the heat treatea,
non-elasticized areas 31, 31' so as to ~orm a plurali~y of
diapers 20 of the type sho~n in FXG . 2 .
Thus, those skilled in the art will appreciate that there
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has herein been described a rather simple, economical
process and apparatus for elasticizing separate discrete
areas of a garment wherein one or more ribbons oE elastic
material are prestretched to a desired extended state,
immobilized i~ that extended state, and spaced selected
discrete areas of the thus extended and immobilized elastic
ribbon(s) are then heated to "kill" the elastic properties
thereof. Adhesive is then applied to the immobilized
ribbon(s) which is (are) then brought into initimate
face~to-face contact with a continuous web moving at
high s~peed and adhesively bonded thereto. More specifically,
at least those portions of the ribbon(s) intermedi~te
the heat treated areas - i.eO, those portions of the
ribbon(s) which still retain their elastic properties--are
bonded to the selected discrete garment areas to be
elasticized while maintaining the ribbon(s) rela-tively
immoblized with respect to both the high friction surface
of roll 66 and the discrete garment areas so that upon
removal of the composite garment and adhesively bonded
ribbons(s) from the high friction surEace of roll 66 and,
where and if required, upon completion of any further
downstream processing and/or assembly steps (not shown),
those portions of the stretched ribbon(s) intermediate
the heated areas are permitted to relax, thereby elasticizing
the discrete selected areas of the garment.
Turning to FIGS. 6 and 7, an exemplary s~stem
has been shown in considerably greater detai~l. Thus,
as here shown, it will be observed that the spools
42, 44 of level-wound TUFTANE are each removably carried
by a pair of suppor-t arms 74, 74' which are respectively
pivotly mounted at 75~ 75' to the frame 76 of the appara-tus~
In order to facilitate removal of empty spools and repl~PmPn-t
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5~
ther~ol'. with ~ully loaded level-~ound spools, th~ spool support
ar~s 7~, 74' are respectively coupled to double-acting fluid
operated cylinders 78, 78' which are operated by ~ny suitable
fluid co~trol means (not shown). The arrangernent is such that
when the opera'or desires to replace the spools, it is merely
necessary to pressurize tlle cylinders 78, 78' so as to pivot
the pairs oE arms 74, 74' countercloc~wise (as viewed in ~IG.
6 ) to a 5pool removal positionO When the empty spools have
been removed and replaced with fully loaded spools, the cylinders
78, 78' are again pressurized so as to pivot the arms 74, 74'
clockwise until the spools 42, 44 respectively engag idler
rolls 51, 519. At thi5 point3 the cylinders 78, 78' may, if
: desired, be depressurized since the weight o~ the spools 42g 44
is sufficient to ~aintain the spools in engage~nent with the
idler ro~ls 51, S1' as the T~FTANE~ ribbons 30, 30' are unwound.
As best shown in FI5. 6, as the TUFTANE~ ribbons 30, 30' are
unwound from the spools 42, 44, the outside diameters of the
~pools are reduced. Consequently, the weight of the spools
sexves to insure that the spools slowly pivot i~ a cloc~wise
direction as viewed in FIG. 6 about pivot points 75~ 75' until
such time that the spools are empty--hexe illustrated by the
phantom line representations ~2a, 44a for the empty spools.
The function of the guide rolls 56, 58 and 56', 58' to
insure proper registration of the ribbons 30, 30' is best
~5 illustrated upon reference to FIG. 7. As hexe shown, it will
be noted that the ribbon 30, for example~ is initially being
unwound fro~ the lower portion of level wound spool 42 as
~îewed in the drawings and as indicated by the soli~ line
represen'~tion for the ribbon 30. As the spool unwinds, the
point of departure of the ribbon 30 from the spool traverses
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the full wid-th of the spool as represented by comparison
of the solid line and phantom line representations oE
ribbon 30. Bu-t, irrespective of where the point of departure
is from the spool 42, the ribbon 30 passes around up-
standing guide rollers 56, 58 which are free to rotate
about fixed vertical axes. Consequently, the ribbons 30,
30' are properly aligned in the machine direction as they
pass around guide rollers 58, 58' and are fed around
sprockets 59, 59' on the tension read-out rollers 60, 60'
(FIG. 6).
In the form illustrated in FIG. 6, provision
is made for further insuring that the ribbons 30, 30'
are maintained immobili2ed relati.ve to the roll 62 during
the selective ~'heat-kill" process. To accomplish this,
an endless nip belt 79 is trained about roll 61, about
approximately 220 o the peripheral surface of roll 62,
and about a series of idler rolls 80, 81 and 82. The
arrangement is such that the ribbons 30, 30' pass over
nip belt 79 as it passes around roll 61 and enter the nip
84 between the nip belt 79 and roll 62. Consequently,
the nip belt 79 serves to hold the ribbons 30, 30' snugly
against the peripheral surface of the roll 62 and, thereby
assists in immobilizing the ribbons 30, 30' relative to
the surface oE roll 62. It has been found that the use of
a nip belt to assist in immobilizing the ribbons relative
to the selective "heat-kill" surface is highly beneficial
when working at relatively hi~h speed operation with a
roll 62 which~ as here, is on the order of 11.14" in diameter.
However, su~h a nip belt has not been found necessary when
opexating with smaller rolls 62.
As previously indicated, after selective heat
treatment by the spaced heated portions 64 of the peripheral
surface of roll 62, the ribbons 30, 30' are passed over a
chill roll 62 and
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e~ter the nip 68 between roll 66 and idler roll 69. Chill roll
62 ser~-es to insure that any heat transferred fro.~ the heated
portions 64 of roll 62 to the surface of the chill roll is
effectively withdrawn so as to prevent heatin~ of the chill
roll ~hich coùld damage the polyethylene web 48. The particular
means e~ployed for ef~ecting cooling of the chill roll is not
sritical to the present invention and has not been illustrated
herein. Any suitable well known conventional cooling means may
be emplo~ed such~ for ~example, as continuous passage of xoom
temperature water through the chill roll 66.
In order to ef~ect a firm bond between the hea~ treated
ribbons 30, 30' and the web 4B, a continuous fine bead B5 of
ho~ melt a~hesive is appliad to the upper ~urfaces of the
ribbons 30, 30~ by means of a 5uitable adhesive extruder 860
5uch hot melt adhesive ~ay take any suitable form. ~Qwever,
excellent results have been achie~ed with a hot melt adhesive
manu~actured b~ H.B. Fuller Company, S~ Paul, Minnesota and
identifi2d as HM 1533, an adhesive ~ont~in;ng a suita~le hot
melt synthetic rubber material a~ailable from Shell.Chemical
Company, Cleveland, Ohio and designated*"Kraton"~ ~hen the
ribbons 30, 30.' enter nip 68, the fine adhesive beads 85 ~ontact
~he surface of the continuous web 48 of polyethylene or the
like~ thus firmly bonding the ribbons to the web~ Since chill
roll 66 is covered with a suitable ~on-slip surface such, for
example, as a soft silicone foam xubber ~aterial, the altexnatin~
fully extended elastic portions 30, 30' and ~he heat treated
extended but non-elastic portions 3~, 31~ which no longer
exhibit elastic properties relative to their environment are
maintained in an immobilized state until adhesive bondin~ to
the web ~8.
* - Trademark
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To insure effectiv~ bonding of ribb~ns 30, 30' to web 48,
provision is made for biasing the roll 69 into engagement with
chill roll 66. To this end, the idlex rolls 69, 71 are mounted
on a pair of bell cranks, one sucll bell crank being illustrated
at B8 in FIG. 6~ The bell cranks 88 are pivotly mounted at 89
to the frame 76 of the apparatus. A suitable fluid at::tuated
double-acting cylinder 90 is provided for con~rollabl~ pivoting
the bell cranks ~8 in a clockwise direction as viewed in ~IG. 6
about pivot point 89, thus urging the idler rol 1 69 into intimate
engagement with chill roll 66 so as to insure that an effective
bond is established ~etween ~he adhesively coated ribbons 3 0,
3 0 ' and web 4 8 .
In operation, provision is made for stretching the elastic
ribbons 30, 30' to a desired extended stretched condition pri~r
to selecti~ely ~heat-killing" the ~lastic properties of alternate
discrete areas khereon. To accomplish this, the driven rolls
52, 52q in the elas~ic r.lbbon supply stand 41 are pr~erably
operated at a surf~ce velocity considerably slower than the
dri~en rolls 62, 66 in the heat treating ~onc 45. Conse-
~0 ~uentl~, the elastic xibbons 30, 30' are stretched between the
respective drî~e xvlls 5~, 52' and roll ~2, thereby providing
fully e~tended stxetched elastic ri3:~ons 30~ 30J entering nip
84 between roll 61 and roll 62 and exiting from roll 62. The
degxee of stretch may be varied by adjustirlg ~he surface speed
di~ferential between the pairs of drisren rolls S2, 52' and
driven roll 62. Typically, the speed dif~erential would be set
so that the elas$ic ribbc)ns 30, 30' axe stretched t~n t:he order
of ab~ut 10~ of their original unextended length; this degree
of stretch nc~rmally insuring comfortable wear o garments to
which elastic ribbons 30, 30 ' are attached. The de~ree o~E
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stretc!l ~s referred to above and he~einafter is d~ined as:
0 X 100~
L~
where Ll is the stretched length and Lo is the lenyth of the
elastic ribbon in its normal contracted stat~.
In carrying out this aspect of the present in~ention, the
"heat-kill" roll 62 and chill roll 66 are preferably inter-
connected by a suitable conventional gear train (not shown) so
as to insure synchronous driving thereof at the selected operatinq
speed of the high speed prod~ction line, and are driven at a
speed on the order of twice the speed of driven xolls 52, 52'~
_ example, assuming operation of the production line at a
speed of x f.p.m~ (where x is preferably controlled to produce
in excess o 250 diapers per minute), the rolls 62, 66 axe
driven at a synchxonous sur~aoe speed of x f . p.m., w~ile rolls
52, 52' are driven at approximately x~2 f~p.m. Tension read-out
rolls 600 60' serve to continually measure the tension ~ the
. resp~ctive stretched elastic ribbons 30, 30~ in a ~nn~r well
known to those skilled in the art and may, therefore, ~e used
in a conventional feedback servo system (not shown) to xe-
spectively adjust the sur~ace speeds of driven rolIs 52~ 52t to
insure that the desired degree of stretch - e.~., 100% stretch--is
maintained~
In operation, it has been found ~esira~le to heat the
portions 64 of the roll 62 to temperatures in the range o~
175 2~5F. Each increment of the elastic ribbons 30~ 30'
will preferably have a dwell time on the order of at least .2~5
seconds while immobilized relative to roll 62; such dwell time
being sufficient to achieve 100~ "kill" of the elastic properties
of the areas of the ribbons 30, 30 t en~aged with the heated
-~7~
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por-tions 64 of roll 62 at any temperature within the range
of 175-225F~ Of course, at slower speeds, dwell time would
be increased. However, in the event that it is necessary to
stop the machine for any given reason, temperatures on the
order of only 175-225F. are not sufficient to melt or
otherwise damage the elastic TUFTANE ribbons 30, 30' during
~he period of down time, but they are sufficient to "kill"
the elastic properties of those portions of the ribbons
that are contact with the heated portions 64 of roll 62
pxovided that the dwell time equals or exceeds .225 seconds.
Those skilled in the art will appreciate that
there ha~e herein been described methods and apparatus
suitable for effectively destroying the elastic properties
of a fully extended, stretched elastic ribbon in spaced
discrete areas while maintaining the ribbon immobilized,
~nd for then affixing the fully extended ribbon to a
con~inuous web while maintA;n;ng the ribbon in its
immobilized extended state relative to the web. As a
consequence, the web and ribbon composite will be eec-tively
elasticized in those areas where the elastic ribbon was in
contact with the unheated high friction surface areas 65
on roll 62; yet, in those areas 31 o the stretched elastic
ribbon which contacted the heated or "kill" zones 64 on roll
62, the elastic properties of the ribbon relative to the
roll 62 and, therefore, relative to the web 48 to which
the ribbon is attached, are effectively destroyed; thus
insuring that the web 48 is effectively elasticized in those
discrete areas where it is bonded to the unheated portions
30 of the elastic ribbons, but is not elast:icized in
those discrete areas where it is bonded to the previously
heated porti.ons 31 of the elastic ribbons.
While the illustrated embodiment example has
herein been described in
~ 28 -
ms/~'~
35~
connecti~n with metllods and apparatus for applying a continuous
fine bead 85 of a suitable hot melt adhesive to tlle surface o'
the extended elastic ribbon 30, it is not necess~ry to pro~ide
a continuous adhesive bond between the ribbon 30 and the web
48. Rather, all that is necessary is that those areas of the
ribbon 30 which are intended .o remain elastic he adhesively
bonded to the web either continuously, intermittently, and/or
at the points of demarcation between the elasticized and non-
elasticized areas of the ribbon; or, alternativelyO that those
1~ areas 31 where the elastic properties of the ribbon have been
altered be adhesively bonaed to the web either continuously~
intermittently, and/or at the points of demarcation be~ween the
elasticized and non-elasticized areas of the web. However, in
the preferred embodiment of the invention wherein the method~
and apparatus herein described are used to ~orm a disposable
diaper ?0 (FIG. 23~ it i5 preferrea that ~t least the unheated
elastic areas of the ribbons 30, 30' be adhesively secured to
the backing sheets 22 deined by web 48 throughout t~e entixe
elas icized crotch portions 28 ~FIGS. 1~ 3 and 4 ) o~ each
~o diaper 20, although such adhesive bonding may be either c~ntinuous
as shown in FIG. 6, or intermittent (not shown).
Those skill~d in the art will further appreciate that the.
selected discrete areas of the elastic ribbon which are to be
heated so as to kill their elas~ic properties rould~ if desirPd~
be heated after being adhesi~ely secured to the con~inuous ~eb
48. In such an arrangement ~not shown~, it ~ould si~ply be
necessary to feed the continuous ~reb 48 into the nip between
nip ~elt 79 and the ribbons 30, 30' as they ar~ delivered to
roll 61 ~Cf., FIG. 6)~ In such an arrangement, however, it
would be necessary to i.nsure essentially perfect re~istration
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of the elastic ribbons with the he~ted portions 64 of the roll
62: i) to ensure that the elastic properties of the ribbons are
"killed" throughout the entire widths of the ribbons in the
selected areas 31 ~FIGS. 1 and 5), and ii) to prevent direct
application of heat to the surface of th~ web 48.
Once the composite of web 48 ~which preferably comprises a
series of interconnected diaper backing sheets 22 -- see, g.,
FIGS . 1 and 3 ) and the thermoplastic elastomeric ribborls 3 0,
. 30 ' has been fonned, the composite may then be passed through
subsequent conventional downstrPam work areas for further
processing. ~n the case of formation o, for example, a
- disposable diaper 20 of the type sh~wn in FIGS. 1-4, the
composite web 48 and elastomeric ribbons 30, 30' w~uld p.re~
ferably fir~t be passed benea~h suitable adhesive extruding
means ~such as that indicated diagramma~ically at 91 in FIG. 6)
where a plurality of ~losely spaced fine lines of a~hesive are
c~ntinuously applied longitudinally of the composite. There~
aftert the comp~site i5 preferably passed through an area (such
as that shown diagrammatically at 92 in FIG. 6) whexe suitable
absorhent batts 24 are deposited on the co~posite. In the
exemplary apparatus, the ~ open-face~ sandwich of wPb 48,
ribbons 30~ 30l, adhesi~e glue lines, and spaced discrete
absorbent batts 24 is then passed through a furthex area
~diagrammatically indicated at 94 in FIG. 6 ) wh~re a continuous
web 95 comprising a plurali~y o~ interconnected fluid permeable
facing sheets 21 ISee, ~ FIGS. 1 and 3~ is superimposed on
the sandwich and adh~sively bonded to the exposed portions of
the backing sheets ~2 by the parallel longituainal glue lines
deposited by the extruder ~1. Finally, ~he thus formed
completed continuous sandwich of interconnected diapers is
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~assed through a sui-table cut-ting area (diclgrammatically
indica-ted a-t 96 in FIG. 6) where the composite is severed
transversely so as to separate successlve dia~ers, there~y
permitting the non-heating elasticized portions of ribbons
30, 30' to contract and forming elasticized diapers such,
for example, as that shown in FIGS. 2 and 4.
Turning now to FIG. 8, there has been illustrated
a slightly modified form of the invention wherein a diaper
sandwich 100 is illustrated having a fluid permeable facing
sheet 21, a fluid impermeable backing sheet 22, an interposed
absorbent batt 24, and elastic ribbons 30 which are not
only secured to the backing sheet 22 but, also, overlie
the margi.nal edges of the absorbent batt 24. Thus, in
this embodiment of the invention, the elastic ribbons
function not only as elasticizing elements but, also, as
an additional moisture barrier.
The above-described method and apparatus for
forming a conformable garment are also disclosed and
are claimed in above-identified parent Application
Serial No. 364,700.
Yet another modification of the invention has
been illustrated in FIG. 9 wherein the elastic TUFTANE
ribbons are somewhat wider than hereinabove described -
e.g~, the ribbons have a width on the order of approximately
2". In this form of the invention, the heated ~ortions
64 of the roll 62 would be shaped (not shown in the drawings)
so as to subject the ribbons to heat throughout virtually
the entire length of each ribbon exce~t for a curved
portion represented in FIG. 9 by the reference numerals
101, 102. Thus, the shaded area 104 of the elastic
ribbons would be subjected to heat to effectively "killl' the
elastic properties thereof relative to the backing sheet 22,
while the areas 101 and 102 are not heated and remain elastic.
Subsequently, the area 102 would be cut away so as to ~rovide
a diaper having a shaped elastic leg or crotch portion where
the elastic portion 101 is curved and on the order of 1/2" in
ms/~
~38~
~idth~ As a consequence of the curved natu.re o~ the elastic
port.ion 101~ the diaper will conform more readily to the leg of
the infant.
32-
