Disposable garments

Here are disclosed disposable garments such as a diaper having adhesive areas on top- and/or backsheet(s) along leg-openings. Each of the adhesive areas is defined by a plurality of spiral adhesive traces. The stretchable elastic means are bonded to the top- and/or backsheet(s) along the adhesive areas, respectively.

BACKGROUND OF THE INVENTION 
The present invention relates to disposable garments and, more 
particularly, to garments such as diaper, incontinence pants or baby 
training pants. 
Garments of such type are usually provided around respective leg-openings 
with elastic means. Conventionally, the elastic means under being 
stretched at a desired elongation percentage are bonded to at least one of 
the top- and backsheets with adhesive applied onto the elastic means 
themselves. The procedure has been also proposed according to which the 
elastic means under being stretched at a desired elongation percentage are 
bonded to the top- or backsheet with adhesive applied onto the top- or 
backsheet. 
The top- and backsheets in such garments preferably have high 
stretchability and suppleness in view of function to be performed by the 
garments. However, both the garments of prior art as have been referred to 
utilize continuous application of hot melt type adhesive and, therefore, 
stretchability as well as suppleness of the top- and/or backsheet(s) are 
necessarily sacrificed particularly when adhesive must be applied onto the 
elastic means or at least one of top- and backsheets in consideration of 
number, width or diameter of the elastic means. 
In conventional practice to fix the elastic means to the top- and/or 
backsheet(s) by curving the elastic means while being stretched in an arc 
so as to extend along the leg-opening and bonding them to the top- and/or 
backsheet(s), the elastic means tend to restore their initial rectilinear 
position under their contractability immediately after they have been 
bonded to the sheet(s) and sometimes they are fixed to the sheet(s) at the 
position offset transversely from the proper position of fixation with 
respect to their longitudinal direction. 
Accordingly, it is an object of the present invention to provide disposable 
garments having around the top- and/or backsheet(s) around the 
leg-openings adhesive areas each defined by a plurality of spiral adhesive 
traces on which the elastic means are mounted so that stretchability as 
well as suppleness of the top- and/or backsheet(s) are not sacrificed and 
the elastic means once mounted on the adhesive areas are not displaced 
therefrom. 
SUMMARY OF THE INVENTION 
The object set forth above is achieved, according to the present invention, 
by disposable garments comprising a topsheet, a backsheet, and stretchable 
elastic means mounted around leg-openings formed on opposite sides of a 
crotch section defined between front and rear sections of the sheets, 
wherein there are provided adhesive areas on at least one of said top- and 
backsheets along curved configurations of the leg-openings, each of the 
adhesive area being defined by a plurality of looped adhesive segments, 
and the stretchable elastic means are bonded to at least one of the top- 
and backsheets along the adhesive areas, respectively. 
Preferably, the stretchable elastic means are stretchable transversely of 
axes of the respective spiral adhesive traces defining the adhesive areas. 
Preferably, each of the elastic means comprises first and second elastic 
members, respective intermediate portions of the first and second elastic 
members being positioned substantially at the central area of the crotch 
section, and opposite end portions of the first elastic member are 
positioned substantially along front halves of the leg-openings, 
respectively, while opposite end portions of the second elastic member are 
positioned substantially along rear halves of the leg-openings, 
respectively. 
In the garments of the present invention constructed as have been 
described, each of the adhesive areas for fixation of the elastic means is 
defined by a plurality of looped adhesive segments having therein fine and 
many non-adhesive spaces. Such feature of the invention minimizes 
deterioration in stretchability and suppleness of the top- and backsheets 
due to presence of the adhesive areas even when the top- and backsheets 
comprise material having the stretchability and suppleness, such as 
fibrous non-woven fabric. 
The feature that the adhesive areas are defined by groups of looped 
adhesive segments and preferably the elastic means are stretchable 
transversely of the axes of the respective looped adhesive segments is 
advantageous in that, even if the elastic means tend to restore their 
initial rectilinear positions, i.e., to contract transversely thereof (in 
the direction transverse of the adhesive areas) to their initial 
rectilinear positions immediately after the elastic means being stretched 
and curved so as to extend along the leg-openings have been bonded to the 
top- and/or backsheet(s) on the adhesive areas, this is prevented by the 
groups of looped adhesive segments. In addition, even if the elastic means 
have actually shifted by going beyond or breaking several looped adhesive 
segments, the elastic means are prevented from completely displacing from 
the associated adhesive areas transversely of the adhesive areas. 
The elastic means comprise two elastic members adapted to diverge from each 
other so as to extend along front and rear halves of the respective 
leg-openings, respectively, and each elastic member comprises a plurality 
of filamentous elastic elements. Accordingly, a contracting force 
generated in one elastic member is not directly transferred to the other 
and thereby the shift or displacement can be avoided further effectively.

PREFERRED EMBODIMENT OF THE INVENTION 
The present invention will be described with reference to an embodiment 
shown by the accompanying drawings. 
Referring to FIG. 1, garments 1 of the invention are illustrated in a 
perspective view. The garments 1 have leg-openings 2 and a waist (trunk) 
opening 3, and these openings are surrounded by associated elastic means 
4, 5, respectively. 
Referring to FIG. 2, the garments 1 are illustrated in an exploded 
perspective view. The garments 1 comprise a topsheet 6, a backsheet 7, a 
mat- or sheet-like core 8, and the elastic means 4, 5. A crotch section 12 
interposed between front and rear sections 10, 11 of the top- and 
backsheets 6, 7 is formed along opposite side edges with notched edges 13, 
14 which respectively define the leg-openings 2. The topsheet 6 comprises 
non-woven fabric being stretchable both in length and width and the 
backsheet 7 comprises non-woven fabric similar to the topsheet 6 and also 
being stretchable both in length and width. Though not shown, suitabe 
plastic film and the like stretchable both in length and width may be 
placed on and bonded to the inner side of the backsheet 7 with adhesive 
(including so-called hot melt type adhesive) intermittently applied onto 
one of the backsheet 7 and the plastic film and the like and, in addition, 
the plastic film and the like may be bonded also to the inner side of the 
topsheet 6 with adhesive intermittently applied onto one of the topsheet 6 
and the plastic film and the like, if desired. In this manner, not only 
the stretchability of the top- and backsheets as the components of the 
garments 1 can be improved but also possible leakage of excretion liquid 
can be avoided. 
The core 8 is sandwiched and bonded between the topsheet 6 and the 
backsheet 7 with adhesive applied intermittently applied onto one of these 
sheets. Intermittent application of adhesive is for the purpose and effect 
of maintaining the top- and backsheets 6, 7 stretchable and supple. 
The top- and backsheets 6, 7 are provided in the crotch section 12 as well 
as in the front and rear sections 10, 11 with the leg-opening elastic 
means 4 and the waist-opening elastic means 5, respectively. 
Each of the leg-opening elastic means 4 comprises a first elastic member 4A 
including a plurality of filamentous elastic elements and a second elastic 
member 4B including a plurality of filamentous elastic elements. These 
first and second elastic members 4A, 4B have their portions adjacent their 
opposite ends intersecting each other substantially at middle locations 4C 
along the respective notched edges 13, 14, respectively, so that 
respective portions 4A.sub.1, 4B.sub.1 of the first and second elastic 
members extending from the respective intersecting locations 4C to the 
outer ends 4D thereof are bonded to the inner side(s) of the top- and/or 
backsheet(s) along adhesive areas 17 which extend, in turn, along the 
respective notched edges 13, 14 while respective intermediate portions 
4A.sub.2, 4B.sub.2 of the first and second elastic members are bonded 
neither to the sheets 6, 7 nor to the core 8 but positioned on the bottom 
side of the core 8 at a central area therof. The intermediate portions 
4A.sub.2, 4B.sub.2 may be spaced from each other depending on various 
factors such as a size and a stiffness of the core 8. While the 
arrangement of the intermediate portions 4A.sub.2, 4B.sub.2 as in the 
illustrated embodiment is most preferred, these portions 4A.sub.2, 
4B.sub.2 may be replaced by separate elastic elements and/or may be fixed 
to the backsheet 7. The elastic means 5 is bonded to the inner side of the 
top and/or backsheet(s) with adhesive around the waist-opening 3. 
Now referring to FIG. 3, arrangement of the first and second elastic 
members 4A, 4B is illustrated by way of example in a plan view. During 
movement of the continuous backsheet 7 longitudinally thereof at a given 
velocity, adhesive is applied thereonto so as to surround individual 
ellipses successively arranged at given intervals to form adhesive areas 
17 while the individual filamentous elastic elements of the first elastic 
member 4A and the second elastic member 4B are inserted into corresponding 
plural guide holes of first and second traverses (not shown) and the first 
and second traverses are actuated so that the first and second elastic 
members 4A, 4B are bonded to the backsheet 7 along the adhesive areas 17, 
describing curves substantially corresponding to sine curves each being 
symmetric with respect to the longitudinal centre line of the backsheet 7. 
The first and second elastic members 4A, 4B shift transversely of the 
backsheet 7 from a starting point P.sub.1 to a turning point P.sub.2 and 
from a turning point P.sub.2 to a starting point P.sub.1, respectively, by 
a width W. An elongation percentage and, therefore, an elongation stress 
increases as these elastic members 4A, 4B shift from the respective 
starting points P.sub.1 to the respective turning points P.sub.2, since 
the first and second elastic members 4A, 4B are stretched as the first and 
second elastic members 4A, 4B having been rectilinearly running 
longitudinally of the backsheet 7 while they are stretched at a given 
elongation percentage are now forcibly deflected transversely of the 
backsheet 7 by the respective traverses and a tension generated by such 
forcible deflection stretches the first and second elastic members 4A, 4B 
as they shift from the respective starting points P.sub.1 to the 
respective turning points P.sub.2. It should be noted here that the degree 
of such stretching effect depends on the velocity at which the first and 
second elastic members 4A, 4B rectilinearly run and the velocity at which 
the traverses transversely move. Spacings in the first and second elastic 
members 4A, 4B, each comprising a plurality of filamentous elastic 
elements, are reduced as these elastic members 4A, 4B are forcibly 
deflected by the associated traverses from running in parallel to the 
longitudinal direction of the backsheet 7 to the transverse direction, 
i.e., from the respective starting points P.sub.1 to the respective 
turning points P.sub.2. It should be noted again that a degree of such 
spacing reduction depends on the running velocities of the first and 
second elastic members 4A, 4B as well as of the backsheet 7. Portions 
(intermediate portions 4A.sub.2, 4B.sub.2, in FIG. 2) of the first and 
second elastic members 4A, 4B defined between each pair or adjacent 
intersections 4C slacken and get close to each other, because the 
backsheet 7 carries no adhesive on the area thereof facing these 
intermediate portions 4A.sub.2, 4B.sub.2. However, these intermediate 
portions 4A.sub.2, 4B.sub.2 also may be bonded to the backsheet 7 with 
adhesive. 
On the continuous backsheet 7 thus provided with the first and second 
elastic members 4A, 4B, the cores 8 are placed at given positions, then 
the continuous topsheet 6 is placed on this assembly to form continuous 
laminate and this continuous laminate is severed along chain-lines 18 into 
individual laminates or garments. The individual laminate obtained in this 
manner is constructed as illustrated in an exploded perspective view by 
FIG. 2. In the individual laminate, opposite side portions 4A.sub.1, 
4B.sub.1, of the first and second elastic members 4A, 4B, respectively, 
have their elongation stress gradually decreasing from their 
longitudinally inner ends (i.e., the respective intersections) 4C or 
adjacent the lower middle of each leg-opening toward their longitudinally 
outer ends 4D or the uppermost point of each leg-opening. In other words, 
the elongation stress gradually increases from their longitudinally outer 
ends 4D toward their longitudinally inner ends 4C. The spacings in the 
opposite side portions 4A.sub.1, 4B.sub.1 of the first and second elastic 
members 4A, 4B, respectively, are gradually enlarged from their 
longitudinally inner ends 4C (i.e., the respective intersections) toward 
their longitudinally outer ends 4D. In other words, the spacings are 
gradually reduced from their longitudinally outer ends 4D toward their 
longitudinally inner ends 4C. 
Referring to FIG. 4, each of the adhesive areas 17 is schematically 
illustrated in a plan view. The adhesive area 17 is defined by a plurality 
of looped adhesive segment 17'. These looped adhesive segments 17' have 
their axes oriented transversely of the backsheet 7 as viewed in FIG. 2, 
i.e., longitudinally of the continuous backsheet 7 as viewed in FIG. 3. 
Accordingly, the axes of substantially all the looped adhesive segments 
17' extend transversely of the direction in which the first and second 
elastic members 4A, 4B extend. The first and second elastic members 4A, 4B 
are fixed to the backsheet 7 between, on or in the respective looped 
adhesive segments 17'. Therefore, even when the first and second elastic 
members 4A, 4B bonded to the backsheet 7 along the respective adhesive 
areas 17 so as to extend along the respective notched edges 13, 14 tend to 
restore their initial rectilinear positions, i.e., to restore their 
positions being transverse of the respective adhesive areas 17 under the 
effect of their contractibility, such restoration is prevented by the 
presence of the looped adhesive segments 17'. Even if the first and second 
elastic members 4A, 4B have shifted toward said direction by going beyond 
or breaking several looped adhesive segments 17', the elastic members will 
be prevented from complete displacing from the respective adhesive areas 
17 toward said direction. The first and second elastic members 4A, 4B 
diverge from the respective intersections toward front and rear halves of 
the respective notched edges 13, 14 and, in addition, comprise the plural 
filamentous elastic elements, so that a direct transfer or contraction 
stress generated in one of these elastic members to the other elastic 
member never occurs and said shift or displacement is avoided further 
effectively. In the illustrated embodiment wherein each of the first and 
second elastic members 4A, 4B comprises a plurality of filamentous elastic 
elements, the previously mentioned function of the looped adhesive 
segments 17' expected with respect to the elastic members is more 
effective than in the case wherein each elastic member comprises an 
integral single member, because the elongation stress is distributed in a 
plurality of filamentous elastic elements and correspondingly weakened. 
Though not shown, the inner side of the topsheet 6 is also provided in 
conformity with the first and second elastic members 4A, 4B with adhesive 
areas similar to the adhesive areas 17. 
The top- and backsheets 6, 7 are bonded together along their outer 
peripheral edges preferably by means of heat seal or adhesive. Preferably, 
the upper side of the core 8 also is intermittently bonded to the topsheet 
6. Said individual laminate constructed in this manner is longitudinally 
folded in two and bonded along free opposite side edges by means of heat 
seal to form the garments 1 as shown by FIG. 1. Within the scope of the 
invention, it is also possible to provide opposite sides of the rear 
section with fasteners (not shown) to complete the waist-opening 3 as seen 
in the conventional disposable diaper of open type, instead of bonding the 
opposite free side edges of said individual laminate by means of heat 
seal. Accordingly, the present invention is not intended to be limited to 
the illustrated embodiment. 
Non-woven fabric used as material for the top- and backsheets 6, 7 may be 
crimped fibrous web having weighing capacity and density enough to offer 
desired liquid-permeability while the core 8 may be an elastic molded 
mixture of fluffy pulp, other fibers and superabsorbent polymer particles. 
It should be understood that the garments of the invention as have been 
described hereinabove may be manufactured, for example, by the method 
disclosed in Japanese Patent Application No. 1989-167224.