U.S. patent number RE37,154 [Application Number 08/629,323] was granted by the patent office on 2001-05-01 for method of manufacturing disposable underpants by applying annular adhesive zones to the backsheet and top sheet for retaining elastic for leg holes.
This patent grant is currently assigned to Uni-Charm Corporation. Invention is credited to Sadanori Matsura, Hironori Nomura, Hirofumi Ohnishi, Taiji Shimakawa, Hiroki Yamamoto.
United States Patent |
RE37,154 |
Nomura , et al. |
May 1, 2001 |
Method of manufacturing disposable underpants by applying annular
adhesive zones to the backsheet and top sheet for retaining elastic
for leg holes
Abstract
Here is disclosed a method for manufacturing individual
disposable underpants provided around a waist line and a pair of
leg-holes with elastic members from two continuous webs and a
plurality of continuous elastic members, characterized by that the
webs are applied on predetermined locations with adhesive so that
the elastic members can be reliably held on the webs although the
elastic members must be forcibly curved when the elastic members
are bonded between the webs with use of adhesive.
Inventors: |
Nomura; Hironori (Iyomishima,
JP), Shimakawa; Taiji (Kanonji, JP),
Matsura; Sadanori (Kanonji, JP), Yamamoto; Hiroki
(Kawanoe, JP), Ohnishi; Hirofumi (Iyomishima,
JP) |
Assignee: |
Uni-Charm Corporation
(Ehime-ken, JP)
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Family
ID: |
15845747 |
Appl.
No.: |
08/629,323 |
Filed: |
April 8, 1996 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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305534 |
Sep 14, 1994 |
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545621 |
Jun 29, 1990 |
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Reissue of: |
745708 |
Aug 16, 1991 |
05147487 |
Sep 15, 1992 |
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Foreign Application Priority Data
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Jun 29, 1989 [JP] |
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1-167224 |
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Current U.S.
Class: |
156/164; 156/494;
156/267; 156/291; 156/269; 156/229; 156/161; 156/204 |
Current CPC
Class: |
A61F
13/15593 (20130101); Y10T 156/108 (20150115); A61F
13/491 (20130101); A61F 2013/49076 (20130101); A61F
2013/53916 (20130101); Y10T 156/1084 (20150115); A61F
2013/49033 (20130101); A61F 13/49011 (20130101); Y10T
156/1015 (20150115) |
Current International
Class: |
A61F
13/15 (20060101); B32B 031/10 (); A61F
013/15 () |
Field of
Search: |
;156/161,164,163,291,229,494,267,269,211,227 ;2/400-402
;604/385.1,385.2,358 ;427/208.6 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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0048011 |
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Mar 1982 |
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EP |
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2169489 |
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Jul 1986 |
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GB |
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2235125 |
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Feb 1991 |
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GB |
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57-77304 |
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May 1982 |
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JP |
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57-117602 |
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Jul 1982 |
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JP |
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Other References
Gibilisco, Stan, "The Concise Illustrated Dictionary of Science and
Technology," McGraw-Hill, Inc, 1993, p. 262.* .
Walker, Peter MB, "Dictionary of Science and Technology," Larousse,
1995, p. 639..
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Primary Examiner: Aftergut; Jeff H.
Attorney, Agent or Firm: Lowe Hauptman Gilman & Berner,
LLP
Parent Case Text
.[.This is a continuation of application Ser. No. 07/545,621, filed
Jun. 29, 1990, now abandoned, and the benefits of 35 USC 120 are
claimed relative to it..].
.Iadd.This application is a continuation of applicaton Ser. No.
08/305,534 filed Sep. 14, 1994 now abandoned, which is a reissue of
Ser. No. 07/745,708 filed Aug. 16, 1991, now U.S. Pat. No.
5,147,487 which is a continuation of Ser. No. 07/545,621 filed Jun.
29, 1990, now abandoned. .Iaddend.
Claims
What is claimed is:
1. A method for disposable underpants comprising steps of:
a) providing adhesive zones centrally on one side of a first
continuous web intermittently along the length thereof;
b) introducing first and second continuous elastic members having a
width narrower than that of a strip of adhesive defining said
annular adhesive zones toward the central area on said one side, of
said first continuous web so that said first continuous elastic
member is laid to bond substantially along a half of said annular
adhesive zone while said second continuous elastic member is laid
to bond substantially along the remainder half of said annular
adhesive zone;
c) providing adhesive zones extending along lateral edges on one
side of at least one of said first continuous web and a second
continuous web;
d) introducing third group of continuous elastic members between
the mutually opposed sides of said first continuous web and said
second continuous web along the respective lateral edges so as to
be bonded between these webs along said adhesive zones;
e) bonding said first and second continuous webs together along
said respective one sides to form a continuous combined web;
f) folding said continuous combined web into two along a
longitudinally central line;
g) cutting off portions of said continuous combined web encircled
within the respective annular zones each comprising said annular
adhesive zone, said first and second elastic members bonded to the
web along said annular adhesive zones, after forming or folding
doube said combined web to form cutouts for leg-holes;
h) providing linear seal zones extending transversely of said
folded continuous combined web centrally through said respective
cutouts for the leg-holes to one lateral edge of said combined web
corresponding to a waist line so as to form continuous series of
underpants; and
i) cutting said continuous series of underpants along each of said
linear seal zones transversely of said continuous series of
underpants so that each of said linear seal zones is divided in two
longitudinally of said continuous combined web and thereby
obtaining individual underpants.
2. The method for manufacturing disposable underpants as recited in
claim 1, wherein, during or after said step "c", said second
continuous web is provided on one side thereof with second annular
adhesive zones to be aligned with the first-mentioned annular
adhesive zones, respectively, and said second annular adhesive
zones are bonded to said first and second continuous elastic
members attached to said first annular adhesive zones.
3. The method for manufacturing disposable underpants as recited in
claim 1, wherein said first and second continuous elastic members
intersect each other at opposite ends of the respective annular
adhesive zones as viewed longitudinally of said web.
4. The method for manufacturing disposable underpants as recited in
claim 1, wherein an absorbent core is placed between each pair of
adjacent said annular adhesive zones prior to combining said first
and second continuous webs one upon another.
5. The method for manufacturing disposable underpants as recited in
claim 1, wherein elastic fibrous nonwoven fabric is used as said
first and second continuous webs.
6. The method for manufacturing disposable underpants as recited in
claim 2, wherein said first and second continuous elastic members
intersect each other at opposite ends of the respective annular
adhesive zones as viewed longitudinally of said web.
7. The method for manufacturing disposable underpants as recited in
claim 2, wherein an absorbent core is placed between each pair of
adjacent said annular adhesive zones prior to combining said first
and second continuous webs one upon another.
8. The method for manufacturing disposable underpants as recited in
claim 2, wherein elastic fibrous nonwoven fabric is used as said
first and second continuous webs.
9. A method for manufacturing disposable underpants comprising the
steps of:
(a) providing a first continuous elongated web (27);
(b) establising a plurality of seperate annular adhesive zones
(30a) each made up of an adhesive strip at spaced apart intervals
along the length of said web (27);
(c) feeding both a first continuous elastic member (25a) and a
second continuous elastic member (25b) toward said web (27) so
that
(1) said first continuous elastic member (25a) is deposited on
approximately a first half of each annular adhesive zone (30a)
(2) said second continuous elastic member (25b) is deposited on
approximately the second half of each adhesive zone (30a)
each of said elastic members (25a, 25b) having a width which is
narrower than the width of the adhesive strip that makes up the
annular adhesive zone (30a);
(d) providing a second continuous web (26);
(e) establishing adhesive zones (32) extending along lateral edges
on one side of at least one of said webs (26,27);
(f) depositing a third group of continuous elastic members (24)
into contact with said adhesive zones (32) set forth in (e);
(g) bonding said first and second webs (26,27) together so as to
form a continuous combined web (28) with all of said elastic
members (25a,25b,24) bonded therebetween;
(h) folding said continuous combined web (28) into two along a
longitudinally central line (34);
(i) cutting off some portions of said continuous combined web (28)
that are encircled within said annular adhesive zones (30a) either
before or after step (h) so as to thereby form cutouts (23) for
leg-holes;
(j) providing linear seal zones (37) transversely of said folded
continuous combined web, said seal zones extending from about the
center of said cutouts (23) for the leg-holes to the lateral edge
of said combined web that corresponds to the waist line so as to
form a continuous series of joined underpants; and
(k) cutting said continuous series of joined underpants along each
of said linear seal zones (37) transversely of said continuous
series of underpants so that each of said linear seal zones (37) is
divided in two longitudinally of said continuous combined web to
thereby obtained individual underpants.
10. The method for manufactureing disposable underpants as recited
in claim 9, wherein said second continuous web (26) is also
provided on one side thereof with a plurality of spaced apart
annular adhesive zones that are aligned with the annular adhesive
zones of said first web (27) and said annular adhesive zones on
said second web (26) are also bonded to said first and second
continuous elastic members (25a,25b) attached to said first annular
adhesive zones (30a).
11. The method for manufacturing disposable underpants as recited
in claim 9, wherein the first and second continuous elastic members
(25a, 25b) intersect each other on opposite sides of the annular
adhesive zones as viewed longitudinally of said web.
12. The method for manufacturing disposable underpants as recited
in claim 9, wherein an absorbent core (8) is placed between each
pair of adjacent annular adhesive zones prior to step (g).
13. The method for manufacturing disposable underpants as recited
in claim 9, wherein elastic fibrous nonwoven fabric is used as said
first and second continuous webs.
14. The method for manufacturing disposable underpants as recited
in claim 10, wherein said first and second continuous elastic
members (25a, 25b) intersect each other on opposite sides of the
annular adhesive zones as viewed longtudinally of said web.
15. The method for manufacturing disposable underpants as recited
in claim 10, wherein an absorbent core (8) is placed between each
pair of adjacent annular adhesive zones prior to step (g).
16. The method for manufacturing disposable underpants as recited
in claim 10, wherein elastic fibrous nonwoven fabric is used as
said first and second continuous webs.
17. A method according to claim 9, wherein step (c) said first and
second elastic members (25a, 25b) are each deposited in a generally
sinusoidal pattern.
18. A method according to claim 17, wherein the sinusoidal patterns
cross over each other in the area between adjacent adhesive zones
(30a).
19. A method according to claim 9, wherein in step (c) said first
and second elastic members (25a,25b) are in a stretch condition at
the time they are deposited on said annular adhesive zone
(30a)..Iadd.
20. In a method for manufacturing disposabe underpants, the step of
applying the elastic comprising the steps of:
a. providing annular adhesive zones on one side of a first
continuous web;
b. laying a tensioned first continuous elastic member in a first
non-linear pattern to bond with at least a portion of at least one
of said adhesive zones;
c. laying a second continuous elastic member in a second non-linear
pattern to bond with at least a portion of said at least one of
said adhesive zones, the first and second non-linear patterns being
substantially symmetrically disposed about a longitudinally central
line;
d. attaching said first continuous web to a second continuous web
to form a continuous combined web; and
e. cutting off a central portion of said continuous combined web to
form a web opening substantially surrounded by the first and second
elastic members..Iaddend..Iadd.
21. The method of claim 20, wherein said step of providing
curvilinear adhesive zones include providing a plurality of oval
adhesive zones on said first continuous web..Iaddend..Iadd.
22. In a method for manufacturing disposable underpants, the step
of applying the elastic comprising the steps of:
a. providing annular adhesive zones on one side of a first
continuous web;
b. laying a tensioned first continuous elastic member in a first
non-linear pattern to bond with at least a portion of at least one
of said adhesive zones;
c. laying a second continuous elastic member in a second non-linear
pattern to bond with at least a portion of said at least one of
said adhesive zones, the first and second non-linear patterns being
substantially symmetrically disposed about a longitudinally central
line;
d. attaching said first continuous web to a second continuous web
to form a continuous combined web; and
e. cutting off a central portion of said continuous combined web to
form a web opening substantially surrounded by the first and second
elastic members,
wherein said step of cutting off a central portion of said
continuous combined web to form a web opening comprises the steps
of:
i. folding said continuous combined web along a longtidinally
central line; and
ii. cutting off portions of said continuous combined web encircled
within said annular adhesive zones to form leg-holes.
.Iaddend..Iadd.
23. The method of claim 22, wherein, after step (b) of claim 22,
wherein the method includes the further steps of:
a. providing linear seal zones extending transversely across said
folded continuous combined web at positions central to said
leg-holes to form a continuous series of underpants; and
b. cutting said continuous series of underpants along each of said
linear seal zones..Iaddend..Iadd.
24. In a method for manufacturing disposable underpants, the step
of applying the elastic comprising the steps of:
a. providing annular adhesive zones on one side of a first
continuous web;
b. laying a tensioned first continuous elastic member in a first
non-linear pattern to bond with at least a portion of at least one
of said adhesive zone;
c. laying a second continuous elastic member in a second non-linear
pattern to bond with at least a portion of said at least one of
said adhesive zones, the first and second non-linear patterns being
substantially symmetrically disposed about a longitudinally central
line;
d. attaching said first continuous web to a second continuous web
to form a continuous combined web; and
e. cutting off a central portion of said continuous combined web to
form a web opening substantially surrounded by the first and second
elastic members..Iaddend.
Description
BACKGROUND OF THE INVENTION
The present invention generally relates to disposable underpants
and, more particularly, to a method for manufacturing such diapers
in the form of underpants and infant training shorts.
Various approaches to such underpants or shorts have already been
well known from, for example, Japanese Patent Application
Disclosure Gazettes Nos. 1982-77304 and 1982-117602. These Gazettes
disclose the methods for attachment of the elastic members to the
waist-hole and the leg-holes of the underpants, particularly along
the curves of the respective leg-holes so as to improve a fitness
around the wearer's legs.
In order to ensure that a continuous elastic member can be
continuously attached to web at locations to be formed into the
waist-hole and the leg-holes, respectively, during continuous
manufacturing basic bodies of underpants from said web, it is
generally required that such continuous elastic member must be kept
stretched at a predetermined ratio when it is attached to said web
at said locations with use of suitable adhesive. Turning to the
above-referred prior art, they disclose the procedure in which the
continuous elastic member carrying said adhesive previously applied
thereon is attached to the continous web.
Generally, when the elastic member is attached to the web while the
elastic member is curved according to the curve, for example, of
the leg-hole, the elastic member tends to restore its initial
rectilinearity, due to its contractility, and sometimes to be
attached to the web at a location deviating from the proper
location at which the elastic member should be attached to the
web.
Such undesirable deviation or shift of the elastic member may occur
also in the above-referred prior art because, according to such
prior art, the elastic member carrying adhesive previously applied
thereon must be attached to fibrous nonwoven fabric having its
surface usually less smooth than that of plastic film and an
adhesive effect is correspondingly low. This necessarily makes any
high speed handling difficult. When the elastic member is
continuously attached to the web while the elastic member is curved
so as to follow the curve of the leg-hole under control of traverse
means, a certain quantity of adhesive is inevitably transferred
onto the traverse means as the elastic member carrying adhesive
previously applied thereon passes by the traverse means. Thus, the
elastic member is peeled off or displaced to deteriorate the
adhesive effect and inconveniently requires frequent cleaning of
the traverse means particularly at the portion thereof where the
elastic member passes by.
Accordingly, it is a primary object of the invention to provide a
method for manufacturing disposable diapers allowing the
above-mentioned problem conventionally encountered by the prior art
to be solved by attaching the elastic member to the web along an
annular adhesive zone in each location to be formed into a leg-hole
wherein said annular adhesive zone is defined by a strip of
adhesive having a width larger than that of the elastic member.
SUMMARY OF THE INVENTION
The object set forth above is achieved, in accordance with the
invention, by a method comprising steps of: providing annular
adhesive zones centrally on one side of a first continuous web
intermittently along the length thereof; introducing first and
second continuous elastic members having a width narrower than that
of a strip of adhesive defining said annular adhesive zones toward
the central area on said one side of said first continuous web so
that said first continuous elastic member is laid to bond along
substantially a half of said annular adhesive zone while said
second continuous elastic member is laid to bond along
substantially the remainder half of said annular adhesive zone;
providing ribbon-like adhesive zones extending along lateral edges
on one side of at least one of said first continuous web and a
second continuous web; introducing a third group of continuous
elastic members between the mutually opposed sides of said first
continuous web and said second continuous web along the respective
lateral edges so as to be bonded between these webs along said
ribbon-like adhesive zones; bonding said first and second
continuous webs together along said respective one sides to form a
continuous combined web; folding said continuous combines web into
two along a longitudinally central line; cutting off portions of
said continuous combined web encircled within respective annular
zones each comprising said annular adhesive zone, said first and
second elastic members bonded to the web along said annular
adhesive zone, after forming or folding double said combined web to
form cutouts for leg-holes; providing linear seal zones extending
transversely of said twofold continuous combined web centrally
through said respective cutouts for the leg-holes to one lateral
edge of said combined web corresponding to the waist line so as to
form continuous series of underpants; and cutting said continuous
series of underpants along each of said linear seal zones
transversely of said continuous series of underpants so that each
of said linear seal zones is divided in two longitudinally of said
continuous combined web and thereby obtaining individual
underpants.
In a preferred embodiment, there are provided on the one side of
the second continuous web additional annular adhesive zones
repectively identical to and associated with said first-mentioned
annular adhesive zones so that said first and second continuous
elastic members are sandwiched between these mutually adjacent
annular adhesive zones.
To manufacture underpants containing therein an absorbent core, an
absorbent core is interposed between each pair of said adjacent
annular adhesive zones prior to bonding said first and second
continuous webs to each other.
According to the present invention, as has been described
hereinabove, there are provided the annular adhesive zones defined
by strips of adhesive having a width larger than that of the
continuous elastic members intermittently along the length of said
web and the continuous elastic members for the leg-holes are
attached to the web along these annular adhesive zones. With a
consequence, the continuous elastic members can be safely and
reliably held on the continuous web without significant
displacement or shift of the continuous elastic members from the
associated annular adhesive zones even if the continuous web is of
fibrous nonwoven fabric. Such effect is enhanced when another
continuous web is provided with the annular adhesive zones in
alignment with the previously mentioned annular adhesive zones,
respectively, so that the continuous elastic members may be
sandwiched between the respective sets of mutually facing annular
adhesive zones.
Finally, said annular adhesive zones are provided on the continuous
web, instead of applying adhesive directly on said continuous
elastic member, so that the problem encoutered by the
above-referred prior art adopting said application of adhesive
directly on the continuous elastic members may be solved.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view showing disposable underpants to be
manufactured by the method according to the invention as has been
completely assembled;
FIG. 2 is an exploded perspective view of said underpants;
FIG. 3 is a schematic diagram illustrating an apparatus for
manufacturing said underpants;
FIG. 4A through 4E and FIGS. 5A through 5C are fragmentary plan
views illustrating respective steps for assembly of said
underpants;
FIG. 6 is a fragmentary perspective view showing, in enlarged
scale, traverse means used in said apparatus;
FIG. 7 is a fragmentary sectional view of said traverse means;
FIG. 8 is a sectional view of a traverse deforming mechanism in
said tranverse means; and
FIG. 9 is a schematic plan view illustrating elastic members under
deformation by said traverse deforming mechanism.
PREFERRED EMBODIMENT OF THE INVENTION
An embodiment of the invention will be described in greater detail
in reference with the accompanying drawings.
FIG. 1 is a perspective view showing disposable underpants to be
manufactured by the method of the invention as has been completely
assembled. The underpants 1 include a waist-hole 2, a pair of
leg-holes 3 and elastic members 4, 5 adhesively attached to the
underpants 1 around these holes so as to form elastic gathers
therearound.
FIG. 2 is an exploded perspective view of said underpants. As seen
in FIG. 2, the underpants 1 comprise a topsheet 6 and a backsheet 7
respectively made of fibrous nonwoven fabric being elastic both in
length and width, a mat-like absorbent core 8 sandwiched between
these sheets, and said elastic members 4, 5. The topsheet 6 and the
backsheet 7 are respectively provided in opposite sides with
notches 13a, 13a and with notches 13, 13b. The core 8 is also
provided in opposite sides with notches 10, 10 so as to present
so-called sandglass-shape. The core 8 is made primarily of fluffy
pulp. The elastic member 4 is bonded in a laterally elastic manner
between the topsheet 6 and the backsheet 7 along waist portions 11,
12 thereof with use of adhesive as will be described. The elastic
member 5 comprises first and second submembers 5A, 5B which
comprise, in turn, three rubber strings having central portions 5a,
5a and opposite side portions 5b, 5b. These rubber strips are
secured between the topsheet 6 and the backsheet 7 only at their
opposite side portions 5a, 5b.
FIG. 3 schematically illustrates an apparatus for manufacturing
said underpants. A continuous web 27 as material for said backsheet
7 is guided by a group of guide rollers 100 and a tensioning roller
pair 101 adapted to tension said web transversely therof into an
adhesive applicator station 102 consisting of rollers 102a, 102b,
102c. At the application station 102, the web 27 is applied
centrally thereon with adhesive of hot melt type of provide oval
adhesive zones 30a which are slightly elongate transversely of said
web 27 and spaced from one another by regular intervals
longitudinally of said web 27. The web 27 is then guided by a
tensioning roller pair 103 adapted to tension said web 27
transversly thereof and a squeeze roller pair 104 onto a rotable
drum 106 in an assembling station 105.
Three continuous elastic members 25A, 25B as said respective
elastic submembers 5A, 5B are stretched by a stretching roller pair
107 as they are guided to traverse means 108, 109.
FIG. 6 and 7 schematically show, in perspective and sectional
views, respectively, arrangement of the traverse means 108, 109. As
shown, the traverse means 108, 109 respectively include support
cylinders 110, 111 positioned adjacent and in parallel with the
squeeze roller pair 104, slidably movable rods 112, 113 inserted
into said support cylinders, respectively, and guide rods 116, 117
suspended from support blocks 114, 115 which are, in turn, fixed to
forward ends of said slidably movable rods, respectively. Said
slidably movable rods 112, 113 are under control of traverse cams
(not shown) linked to base ends of these rods 112, 113,
respectively. The guide rods 116, 117 are provided in lower ends
thereof with guide holes 118, 119 through which said elastic
members 25A, 25B are respectively inserted. The lower ends of the
guide rods 116, 117 are closely adjacent peripheral surfaces of the
squeeze roller pair 104. The slidably movable rods 112, 113 are
movable by distances between positions of the respective guide rods
116, 117 indicated by solid lines and positions of said rods 116,
117 indicated by chain lines in FIG. 7 under control of said
traverse cams. As the slidably movable rods 112, 113 and, hence,
the guide rods 116, 117 are moved under such control, the elastic
members 25A, 25B which are finer than the strips of adhesive
defining said adhesive zones 30a on the web 27 are laid to bond on
said web 27 traveling together with said adhesive zones 30a so that
elastic member 25A, 25B follow substantially halves of each pair of
adjacent adhesive zones 30a, then intersect each other in the area
defined between these adjacent adhesive zones 30a and follow the
remainer halves thereof, describing a pair of sine curves, as shown
by FIG. 4B.
FIG. 8 is a fragmentary sectional view showing a mechanism adapted
to control movement of the slidably moveable rod 112 and the guide
rod 116 and thereby to partially deform the sine curve described by
said elastic member 25A, and FIG. 9 is a plan view showing said
sine curve thus partially deformed. Referring to FIG. 8, adjacent
the forward end of the support cylinder 110 shown in FIG. 6, there
are stationarily provided on the slidably movable rod 112 a pair of
regulator blocks 120, 121 spaced from each other along the length
of said slidably movable rod 112 and a support block 114 is
slidably mounted on the portion of the slidably movable rod defined
between the regulator blocks 120, 121 as well as on a guide rail
122 extending between said regulator blocks. A coil spring 123 is
loaded between the support block 114 and the regulator block 120. A
stopper 125 extends from a stationary component 124 so that the
stopper 125 may contact an opposed side surface of the support
block 114 and thereby limit movement thereof. If the slidably
movable rod 112 is not provided with such mechanism, the elastic
member 25A would discribed a sine curve having a circular section
25A' as the slidably movable rod 112 and the guide rod 116 are
moved whereas, in the case as shown by FIG. 8 in which the slidably
movable rod 112 is provided with such mechanism, upon contact of
the support block 114 supporting the guide rod 116 with the stopper
125, said sine curve of the elastic member 25A is deformed so as to
describe a linear section 25" corresponding to a period during
which the guide rod 116 is temporarily stopped by the stopper 125
bearing against the support block 114. Such deformed sine curve of
the elastic member 25A is designed in accordance with the
configurations of the leg-holes 3 shown in FIG. 1 and the wearer's
front crotch in order to improve the fitness.
The web 27 including the elastic members 25A, 25B laid thereon in
the manner as has been mentioned above is squeezed between the
squeeze roller pair 104 and thereby said elastic members are
adhesively bonded to said web. On this point, the portions 25a, 25a
of the respective elastic members 25A, 25B not lying within the
adhesive zones 30a contract to present substantially rectilinear
shape, as seen from FIG. 4C.
Referring again to FIG. 3, a continuous web 26 as material for said
topsheet 6 is guided by a guide roller 126 and a tensioning roller
pair 127 adapted to tension said web 26 transversely thereof to an
adhesive applicator station 128 comprising rollers 128a, 128b,
128d. At the applicator station 128, the web 26 is applied
centrally thereon with hot melt type adhesive to provide oval
adhesive zones 30b which are slightly elongate transversely of said
web 26, as shown by FIG. 4D. Shape, size and spacing of this
adhesive zone 30b are substantially identical to the previously
mentioned adhesive zone 30a. Simultaneously, the web 26 is provided
with rectilinear adhesive zones 31 extending from opposite sides of
said adhesive zone 30b to the adjacent lateral edges of the web 26,
respectively, and continuous rectilinear adhesive zones 32
longitudinally extending along the lateral edges of the web 26 by
application of hot melt type adhesive occuring at said applicator
station. Then, the web 26 is introduced by a tensioning roller pair
129 also adapted to tension the web 26 transversely thereof between
the rotatable drum 106 and a pressure roller 130 cooperation with
said drum.
The continuous elastic members 24 as material for said elastic
members 4 are stretched to a desired ratio and guided
simultaneously by a stretching roller pair 131 so as to be laid and
bonded along the adhesive zones 32 formed along the lateral edges
of the web 26, as shown by FIG. 4E.
Referring again to FIG. 3, the individual cores 8 previously formed
and placed at regular spacings on a porous belt conveyor 133
adapted to be moved over the top of a device 132 having a
relatively feeble suction effect and conveyed by the belt conveyor
133 to the assembling station 105. As will be apparent from FIG. 2
and FIG. 4C (as indicated by chain lines), each core 8 presents
so-called sandglass shape and located between each pair of adjacent
adhesive zones 30a or each pair of adjacent loop portions formed by
the elastic members 25A, 25B, respectively, on the web 27. Upon the
web 27 carrying the core 8 disposed thereon, the web 26 is placed
so that said adhesive zones 30a, 30a are aligned with said adhesive
zones 30b, 30b. In this manner, the respective loop portions of
said elastic members, 25A, 25B are properly sandwiched between said
webs 26, 27 at said adhesive zones 30a, 30b and the elastic members
24 are also properly sandwiched between these webs 26, 27 along
their lateral edges. Thus, the webs 26, 27 sandwiching the cores 8
and the elastic members 24, 25A, 25B therebetween are squeezed
between the rotatable drum 106 and the pressure roller 130 to form
the continuous combined web 28 and simultaneously to fix the cores
8 and the elastic members 24, 25A, 25B within this combined web
28.
The combined web 28 enclosing the cores 8 therein is then pressed
at a press station comprising a belt conveyor 135 traveling on the
top of a cradle 134 and pressure rollers 136 and thereafter guided
to a heat (or sonic) seal roll pair 138. The combined web 28 is
heat sealed by the seal roll pair 138 at oval zones 21 defined by
each pair of adjacent cores 8 and rectilinear sections 22 extending
from opposite sides of the respective oval zones 21 to the adjacent
lateral edges of the combined web 28, respectively, as shown by
FIG. 5A. In this case, excessively hardened heat seal is
undesirable. It should be understood that this process is not
necessarily essential to the invention.
The combined web 28 thus process is now guided by a guide roller
139 to a roll cutter 140 by which a hatched central area 21' of the
oval zone 21 is cut out to form the cutout 23 for the leg-hole. The
central area 21' comprises portions of the webs 26, 27 lying inside
each of the annular zones formed by the adhesive zones 30a, 30b and
the elastic members 25A, 25B adhesively bonded therealong.
The combined web 28 thus formed with the cutouts 23 is guided by a
guide roller 141 to folding means 142 of which detals are not
shown. The folding means 142 may be of the arrangement well known
in the apparatus for manufacturing disposable diapers, sanitary
napkins or the like. The combined web 28 is folded by the folding
means 142 along a longitudinally central line 34 as seen in FIG. 5A
in two, as shown by FIG. 5B.
The twofold combined web 28 is guided to a heat (or sonic) seal
roll pair 143 by which the web 28 is formed with linear or
ribbon-like heat seal zones 37 extending adjacent imaginary cutting
lines 36 on opposite sides of the individual underpants 1 and
thereby a continuous series of underpants 29 is formed.
The coninuous series of underpants 29 is guided by a guide roller
145 to a roll cutter 144 by which said continuous series of
underpants is successively cut along the imaginary cutting lines 36
or at the heat seal zones 37 into the individual underpants 1 which
are then transported by a belt conveyor 146 to a packagine process
(not shown).
When a liquid impermeable web is employed as said continuous web 27
which is material of said backsheet 7 and it is desired to make at
least the central zone of said backsheet at which said core 8 is
disposed on said backsheet in order to avoid any possibility of
body fluid leakage occuring therethrough said central zone, it is
preferred to bond the liquid inpermeable web, preferably such web
having elasticity made of plastic film or the like to the web 27
prior to placement of said elastic members 25A, 25B. In such a
case, referring to FIG. 3, the web 27 is centrally applied with hot
melt type adhesive in dotted pattern as the web 27 passes between a
pressure roll 147 and an applicator roll 148 so that a liquid
impermeable continuous web 40 may be bonded to said central zone.
Accordingly, application of adhesive by said applicator station 102
as well as placement of the elastic members 25A, 25B are preformed,
in this case, partially both on the web 40 and on the web 27.
Preferably, said webs 26, 27 are of nonwoven fabric which is
elastic both in length and width or at least in width, said core 8
is made of fluffy pulp which was mixed with super-absorbent polymer
powder and molded together, and said elastic members 24, 25A, 25B
comprise natural or synthetic rubber strings or tapes, or plastic
films presenting elasticity upon heat treatment. Said core 8 may be
omitted depending on particular application of the underpants.
It should be understood that the step of FIG. 5A may be replaced by
the step of FIG. 5B to cut out the central area 21' of said
combined web 28 in forming said cutout 23 for the leg-hole.
Furthermore, the adhesive zones 30a, 30b, 31, 32 may be applied
with adhesive continuously extending overall on these zones, or in
a plurality of dots, intermittent lines or helical lines.
* * * * *