Note: Descriptions are shown in the official language in which they were submitted.
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BACXGROUND OF THE INVENTION
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The present invention relates to absorbent articles.
A various assortment o:E ab~orbent articles, such as
: disposable diapers and sanitary napkins, have been proposed for
absorbing and retaining body fluids. Such artiales have been con-
structed with an absorbent pad having a relatively large volume
of pad material, in order to provide the necessary absorbency and
fluid holding capacity for the articles, which adds an undesired
bulk to-the articles. For example, disposable diapers are com- :
monly made from a fluid impervious backi~g 5heet, a fluid pervious
cover sheet, and an absorbent pad, such as comminuted wood pulp ~ ~ ~
known in the art a~ wood fluff~ located between the backing and : :
~: cover sheets. The pads of su~h conventional diapers.are relatively
bulky, resulting in a poor fit and minimal comfort to the infant.~
More recently, it has been proposed to include highly ~ .
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absorbent materialsj such as hydrocolloid polymers, in the pads.
; In theor~, the hydrocolloid.materials permit a reduction in pad
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bulk:wh~le incxeasing desirable absorbent and ~luid holding char-
acteristics of the pads, since~such materials are capabl~ of
. 20 absorbing and;r aining many times their weight in liquid, suah
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; as urine or other body luids. In practice, use of:such material~
in absorb~nt article~ has been limited due to d~f~icultie~ ~aused
by the nature of the material~
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. ~ It has.been contemplated that the hydrocolloid material~.
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~. 25 may be placed in a central region of the artic.les at a location
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~: where body fluids,~such a:s urine, are applied to.the art:icles.
., However, the hydrocolloid material swell and become ge1atinous.
when wetted, and it has been ~ound that the we~ted material~ form
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1092~32
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a film on the pad whicll decreases the rate of Further fluid penetration into
the pad. Thus, although -the materials initially absorb the body fluids, they
may later cause saturation and back wetting of the Fluids in the central
fluid receiving region of the articles. ~oreover, in general it is desirable
to retain the body fluids at a location spaced from the point of application
~o the articles in order to make maximum use of the pad.
SUMMARY OF T~IE INVENTION
A principal feature of the present invention is the provision of
- an absorbent article of simplified construction which absorbs and retains
body fluids in an improved manner.
- According to the present invention there is provided an absorbent
article comprising, a fluid pervious top sheet, a backing sheet of fluid
impervious material, and an absorbent pad intermediate the top and backing
sheets, said pad having a fluid receiving region adjacent a lateral central
portion of the pad and a hydrocolloid material at a location spaced from ~
said fluid receiving region, said fluid receiving region being substantially `
` free of said hydrocolloid material.
The pad preferably has the hydrocolloid material positioned in
- opposed margins of the pad adjacent opposed edges of the pad.
With an article of this construction, the hydrocolloid material in
the article enhances the absorbent and fluid holding capacity of the pad.
At the same time, body fluids are retained at pad locations spaced from the
fluid receiving region in order to minimize the possibility of pad saturation
in the fluid receiving region and to maximize use of the pad material. With
this pad cou~lguratioù,
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the subs~antially free fluid receiring region prevents formation
of a film by the hydrocolloid mater.ial which would otherwise de-
crease the ra~e of fluid passage into the pad. :
: In one preferred embodiment, the backing sheet includes
opposed front margins overlying a front surface and the margins
` of the pad in order to encapsulate the hydrocolloid material with : :
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fluid impervious material and minimize the possibility of leakage ;,
from the pad margins.
Further features will become more fully apparent in the `~
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10following description of preferred embodiments of this invention.
In the drawings~
` Figure 1 is a fragmentary front plan view of an absorb-
ent article of the present invention, sho~n in the form of a dis~
~- posable diaper;
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Figure 2 is a fragmentar~ sectional view taken substanti-
ally as indicated along the line 2-2 of Figure l;
1 Figure 3 is a plan view of an absorbent pad for the `
:. article of Figure l;
~, Figure 4 is a perspecti~e view of the article of Figure
201 as folded lnto a box-pleat configuration; ;
~:1 Figure 5 is a fragmentary sectional vie~ of another
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embodiment of the article of the present invention; and
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Figure 6 is a fragmentary sectional view of another
embodiment of the article of the present inve~tion.
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DESCRIPTION OF THE ,PREE'ERRED EMBODIMENTS
Referring now to Figs. 1 and 2, there is shown an
absorb~nt article generally designated 20 having an absorbent pad
assembly 22, For convenience, t~he article 20 is disclosed in the
form of a disposable diaper, alt~hough it will be understood that
the invention is applicable to other absorbent articles, such as
sanitary pads and maternity napkins.
The pad assembly 22 has a flui~ impexvious backing sheet
24, such as poIyethylene, defining a back surface 26 of the article
or diaper, a fluid pervious top or cover shee~ 28 defining a front
: surface 30 ~or the diaper, and an absorbent pad~32 positioned~
: intermediate the top sheet 28 and backing sheet ~4. Th~:absorbent~ :
pad 32 may have a pad portion 34 comprising a cellulosic m~terial,
su~h as one or more sheets of cellulosic wadding or comminuted
` 15 wood pulp kno~n in the art as wood fluff, a back:wadding sheet 3~ :
- o`f celluloslc material defining a back surface~38 of;the pad 32,
and a~front~wadd~ing sheet 40 of~cellulosic material de~inlng a~
front surface 42 of: the pad 32. The front~and back wadding ~heets ~:
40 and 36, respectively, provide structural integrity for the~pad
~porticn 34 during:use of the articleO :
-~` ;The pad assembly 22 has a pair o~ siae edges 44 and end
;~: edges 46 ~onnecting the side edges 44, and the absorbent pad 32:
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~has a pair o~ side edges 48 and end edges 50 connecting the side
edges 48. In a preferred ~orm, the side edges 48 of the pad 32
: ~ 25 are located adjacent the side edges 44 of the.pad assembly 22, and
: the back~ng sheet 24 has lateral side margin 52~olded over and`
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: secured to the top sheet 28 over the pad 32. ~he diaper may also~
have tape fasteners~54 for use in securing the diaper about an
~ . ~ infan~during placement of the diaper.
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: With reference to Figs. 1-3, the pad 32 has a pair of
lateral side margins 56 adjacent the pad side edges 48 and extend-
ing longi~udinally between the end edges 50 o~ the pad, and a fluid
receiving region sa intermediate the side margins 56 in a lateral
central portion of the pad 32. As shown, the lateral side margin~
56 of the pad 32 have a hydrocolloid material 60, while the fluid
receiving region at the point of application of body fluids to the
pad 32 is substantially free of the hydrocolloid material. In a
preferred form, the hydrocolloid material 60 is dispersed in the
side margins 56 substantially between the end edges 50 of the pad~
: 32. In an alternative form, with reference to~Fig. 3, the:hydro~
colloid material may be located in end margins~61 of the pad adja- . -
cent the end edges 50 such that the fluid receiving region 58 is
. located in a longitudinal central portion of the pad intermediate
:- 15 the end margins 61, or the material S0 may be located in bcth the :
é side and end margins 56 and 61 which surround~the region 58.
. The hydrocolloid material 60 may be ofjany suitable
. .~ type, such as (a) hydrolyzed starch polyacrylonltrile copolymer
H-span,~Produat~35-A-lOO, Grain Processing Corp~., Muscatine,
Iowa, discloced in U.S. Patent No. 3,661,815, (b) Product No. . .
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: XD-8587.01L, which is cross-linked, Dow Corning Chemical Co.,
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Midland, Michigan, (c) Product No. SGP 502S, General Mills
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hemical, Inc., Minneapolis, Minnesota, (d) Product No. 78-3710,
~ National;Starch and Chemi~al Corp., New York,.New York, (e3 a
:, 25 hydrogel base product, Carbowax, a trademark ~f Union Carbide
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Corp., Charleston, West Virginia, or (f) base-saponisied starch- :
polyacrylonitrlle and graft copolymer~, United States Department
of Agricultur~, Peoria, Illinois, disclosed in U.S. Patent No.
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3,425,971. Such hydrocolloid materials have the capacity of
absorbing many ~imes their weight in liquids such as urine or
other body fluids, and swell and form a gelatinous mass when
wetted. In general, the hydrocolloid materials useful in the
articles of the present invention may be organic or inorganic,
are physiologically non-objectionable (non-toxic), and are
characterized by swelling in the presence of water, by a rela-
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tively high affinity for water, and by normally at least parti-
ally assuming a suspension in the presence of water. Additionally
it has been found that the materials tend to form a film when
wetted which impedes passage of body fluids into the pad if
retained at the point of application of fluid6 into the pad, thus
causing saturation of the pad and possible back wetting through ~ -~
the top sheet in the fluid receiving region.
With reference to Figu es 1 and 2, the front surface of
the pad portion 34 in the side margins 56 may be wetted slightly,
and the hydrocolloid material 60 may be placed on the wetted front
surface of the pad portion 34 after which the front wadding sheet 40
is positioned over the pad portion 34, such that the hydrocolloid
material 60 is located adjacent the front surface 42 of the pad 32
with the moisture~facilitating retention of the materlal 60 in the
side margins 56. In an alternative form~ with reference to Figure
6, the ~hydrocoIloid materlal 60 may be placed against the moistened
back surface of the pad portion 34 after which the back waddirg
sheet 36 is positioned orer the back surface of the pad portion 34,
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~ such that the hydrocolloid material 60 is positioned adjacent the ~
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back sur~ace 38 of the pad 32. In either event, the hydrocolloid
material 60 is located in the side or end margins at a position
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spaced from the fluid receiving region 58 of the pad 32.
In use, the diaper is secured about 3n infant through
use of the tape fasteners 54 in a kno~n manner. During voiding,
`' the urine passes into'the pad 32 in the fluid receiving region 58
S and spreads to the lateral side margins 56 where the hydrocolloid
material absorbs and retains the body fluids at a location spaced
from the fluid receiving region 58. Thu~, the body fluid3 are
: retained at pad locations spaced from the point of app1ication to
the diaper, in order to make maximum use of the pad material. Addi-
: 10 tionally, the fluid receiving region 58 of the pad 3~ is ~ubstant~
ally free of the hydrocolloid material, ln order to prevent;forma~
.~ tion of a film by the wetted hydrocolloid materials in the region '~
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:. 58 which would atherwise impede passage of body fluld~ into the'pad, ,
` thus minimizing the possibility of fluid satu~ation in the region
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: 1; 58 and accompanylng back wetting from the pad through the top sheet ~ :
against the infantO
, Another embodiment of the present in,vention is illus-
'~ trated in Fig. 5, in which like refexence numerals designate like
: parts. In this embodiment, the lateral margins 52 of the backing
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sheet 24 extend a suffi~ient distance inwardly~from the ~ide
edges 48 of the pad 32 to overlie the lateral pad side marglns 56.
, Thus, the backing sheet side marginæ 52 cover the pad margin~ 56
- - and the hydrocolloid material 60, such that ~hè backing sheet 24
forms fluid impervious pockets which minimize''the pos~ibility of
~' ~ 25 leakage from the'pad side margins 56 where the fluid~ are retained
by the hydrocolloid material 60. .,
With reference to Figs. 1, 2, and 4, the diaper may be .
folded into a b~x-pleat configuration in a manneF described as
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follows. The pad assembly 22 is folded along a pair o~ first
fold lines 62 defining a longitudinally extending central panel
64 intermediate the fold lines 6;2, and a pair of second fold
lines 66 defining a pair of long:itudinal first panels 68 whi~h
; 5 extend between the fold lines 62 and 66 and which overlie the cen-
tral panel 64. The second fold lines 66 de~ine a pair of ou~er-
most panels 70 extending from the second fold lines 66 and overly-
ing the first panels 68. In a preferred form, as shown, the lat-
eral side margins 56 of the pad 32 are located in the outermo~t
panels 70 o~ the folded diaper, such that the first panels 68 sepa- `
rate the central panel 64 and the hydrocolloid material 60 retained~
: in the outermost panels 70.
: ~ The foregoing detailed description is given for olear-
ness of understanding only, and no unnecessary limi~tation~ should
15 be understood therefrom, as modifications will be obvious to those
- skilled in the art.
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