Absorbent article with free edge portions

The present invention provides an absorbent article 1 having a substantially elongate configuration, comprising a liquid-impermeable leakage-preventive layer 3, and a liquid-retentive absorbent layer 2 disposed above the leakage-preventive layer 3, wherein the absorbent layer 2 comprises a liquid-retentive absorbent member 24 and a liquid-permeable topsheet 23, and is formed by a fixed portion 21 and one pair of left and right free edge portions 22, the fixed portion 21 being fixed to the leakage-preventive layer 3, the free edge portions 22 being located on opposite left and right sides in the longitudinal direction of the fixed portion 21 and each having a free end 22a, the absorbent member 24 being present in both of the fixed portion 21 and the pair of left and right free edge portions 22.

BACKGROUND OF THE INVENTION
 This invention relates to an absorbent article such as a sanitary napkin,
 an incontinent pad, or the like, which has a nice fitness and a high
 leakage-preventive ability.
 As an absorbent article, such as a sanitary napkin, an incontinent pad, or
 the like, there has heretofore been widely used a substantially
 vertically-long absorbent article including a liquid-retentive absorbent
 layer and a liquid-impermeable leakage-preventive layer.
 Such an absorbent article is required to prevent leakage, particularly to
 effectively prevent leakage from the side portions, and many proposals
 have been made.
 For example, in Japanese Utility Model Unexamined Publication (KOKAI) No.
 1-2592, there is proposed a sanitary napkin, in which elastic members are
 arranged on both left and right side edge portions of an absorbent article
 so that a round-shaped configuration is exhibited on the body side of its
 user in a natural state.
 In such a suggested sanitary napkin, however, the napkin, when in wear,
 tends to move together with the shorts in obedience to the motion of the
 wearer, and therefore, fitness is degraded and leakage occurs when
 slipped.
 In Japanese Patent Unexamined Publication (KOKAI) No. 8-503638, there is
 proposed an absorbent article, in which cubic gathers comprising a
 topsheet, a backsheet, and an elastic member are provided on both left and
 right guide of an absorbent member such that the cubic gathers are
 erected.
 Such a proposed sanitary napkin, however, cannot satisfy the required level
 of leakage-preventive ability and the leakage-preventive ability from the
 sides is degraded.
 SUMMARY OF THE INVENTION
 It is, therefore, an object of the present invention to provide an
 absorbent article, which has a nice fitness and a high leakage-preventive
 ability, and which is particularly capable of preventing leakage from the
 sides effectively.
 As a result of search and development with a view to solving the above
 problems, the present inventors have found that the above object can be
 achieved by providing an absorbent article comprising a fixed portion
 forming an absorbent layer fixed to a leakage-preventive layer, and free
 edge portions each located on both left and right sides of the fixed
 portion and each having a free end.
 The present invention provides an absorbent article having a substantially
 elongate configuration, comprising a liquid-impermeable leakage-preventive
 layer, and a liquid-retentive absorbent layer disposed above the
 leakage-preventive layer, wherein the absorbent layer comprises a
 liquid-retentive absorbent member and a liquid-permeable topsheet, and is
 formed by a fixed portion and one pair of left and right free edge
 portions, the fixed portion being fixed to the leakage-preventive layer,
 the free edge portions being located on opposite left and right sides in
 the longitudinal direction of the fixed portion and each having a free
 end, the absorbent member being present in both of the fixed portion and
 the pair of left and right free edge portions.
 The absorbent article according to the present invention has a nice fitness
 and a high leakage-preventive ability, and is particularly capable of
 effectively preventing leakage from the sides.

DESCRIPTION OF THE PREFERRED EMBODIMENTS
 An absorbent article according to the present invention will be described
 hereinafter in detail with reference to the drawings.
 Here, FIG. 1 is a perspective view showing a sanitary napkin as the first
 embodiment of an absorbent article according to the present invention,
 FIG. 2A is a sectional view taken on II--II of FIG. 1, and FIG. 2B is a
 sectional view taken on line III--III of FIG. 1.
 A sanitary napkin 1 according to the first embodiment shown in FIGS. 1, 2A,
 and 2B has a substantially elongate configuration, including a
 liquid-retentive absorbent layer 2, and a liquid-impermeable
 leakage-preventive layer 3. When in use, the napkin 1 is attached to an
 undergarment.
 In the sanitary napkin 1 according to this embodiment, the absorbent layer
 2 comprises a liquid-retentive absorbent member 24 and a liquid-permeable
 topsheet 23, and is formed by a fixed portion 21 fixed to the
 leakage-preventive layer 3 and one pair of left and right free edge
 portions 22 located on opposite left and right sides in the longitudinal
 direction of the fixed portion 21 and each having a free end 22a, the
 absorbent member 24 being present in not only the fixed portion 21 but
 also in the pair of left and right free edge portions 22.
 When the sanitary napkin 1 according to this embodiment is used, the
 leakage-preventive layer 3 moves directly in obedience to the motion of an
 undergarment, but the one pair of free end portions 22 on the absorbent
 layer 2 do not move directly in obedience to the motion of the
 undergarment.
 More specifically, the free edge portions 22 have each an elastic member 25
 arranged over a predetermined length along a longitudinal direction of the
 absorbent layer 2, the free edge portions 22 being erected towards a skin
 contacting surface side by contraction of the elastic member 25. The
 expression "erected" used herein refers not only to an upright state but
 also to an upwardly floated state from the leakage-preventive layer.
 The topsheet 23 is arranged in such a manner as to cover at least the skin
 contacting surface side of the absorbent member 24, the fixed portion 21
 is located on a widthwise central portion of the absorbent layer 2, and
 the one pair of free edge portions 22 are continuous with opposite left
 and right side edges of the fixed portion 21, respectively. The term
 "continuous" used herein refers to a state that the side edge of the fixed
 portion 21 and the side edges of the free edge portions 22 are continuous
 with each other.
 As shown in FIGS. 2A and 2B, the absorbent layer 2 comprises the absorbent
 member 24, and the topsheet 23 provided in such a manner as to cover an
 outer surface and side surfaces of the absorbent member 24 and back
 surfaces (the portion not contacting the leakage-preventive layer 3) of
 the free edge portions 22. Owing to this arrangement, the absorbent member
 24 is present over the widthwise entire area of the absorbent layer 2. In
 the absorbent layer 2, a second absorbent layer 27 is disposed on the
 fixed portion 21 between the topsheet 23 and the absorbent member 24.
 As shown in FIG. 2, the leakage-preventive layer 3 comprises a
 liquid-permeable sheet 31, a leakage-preventive sheet 32, and an
 absorptive portion 33 interposed therebetween. That is, as shown in FIG.
 2, in the leakage-preventive layer 3, the absorptive portion 33 consisting
 of an absorbent sheet(s) is held between the liquid-permeable sheet 31 and
 the leakage-preventive sheet 32, and the liquid-permeable sheet 31 and the
 leakage-preventive sheet 32 are sealed at a peripheral edge portion of the
 absorptive portion 33.
 The absorbent layer 2 is placed on the liquid-permeable sheet 31 of the
 leakage-preventive layer 3 and fixed by bonding thereto through an
 adhesive agent 4 applied to opposite left and right side edge portions of
 the fixed portion 21. Longitudinal opposite end edges of the absorbent
 layer 2 and the leakage-preventing layer 3 are fixed by heat sealing.
 The width W1 of the fixed portion 21 is preferably 15 to 60 mm. The width
 W2 of the free edge portions 22 is preferably 5 to 30 mm.
 The elastic member 25 is disposed generally over entire area in the
 longitudinal direction of the absorbent member 24 along the opposite left
 and right side edge portions 24a, 24a of the absorbent member 24, on the
 back surface side of the absorbent member 24 at the fee ends 22a of the
 free edge portions 22.
 As a material forming the elastic members 25, 25, a film, a fiber, a foamed
 body and the like composed of a polymer of a number of rubbers, such as
 polyurethanes, polybutadiene, isoprene and the like, ethylene-vinyl
 acetate, and a number of polyolelins having extensibility can be used. In
 order to obtain favorable effects (desired effects of the present
 invention) without degrading the comfortable wearing perception, the
 elastic members 25, 25 are preferably 10 to 300 gf in stress at 30%
 expansion.
 The predetermined length for the arrangement of the elastic members 25, 25
 is not particularly limited. In order to erect the free edge portions 22,
 22 into a configuration nicely fitted to the wearer, the elastic member
 25, 25 are disposed preferably over the length of 15 to 90% of the entire
 length of the sanitary napkin 1, and more preferably over the length of 50
 to 90%.
 The leakage-preventive layer 3 is provided on a back surface side thereof
 with a slip-preventive means 34 for attaching the sanitary napkin to an
 objective member to be attached such as an undergarment when in use. The
 width W3 of the sanitary napkin fixed by the slip-preventive means 34 is
 preferably larger than the width W1 of the fixed portion 21 of the
 absorbent layer 2 because in doing so, the leakage-preventive layer
 becomes easier to move in obedience to the motion of the undergarment. The
 slip-preventive means is not particularly limited inasmuch as it is
 usually used, such as a double faced adhesive tape, a hot-melt adhesive
 agent, a mechanical hook, or the like. In this embodiment, a hot-melt
 agent is applied so as to be used as the slip-preventive means.
 In this embodiment, two straps of the slip preventive means 34 are provided
 on the side of opposite left and right side edges in the longitudinal
 direction of the sanitary napkin 1. The width W3 refers to the width
 between the outer edges of the two straps of the slip preventive means 34,
 34. In case two or more straps of the slip preventive means 34 are
 provided, the space between adjacent slip preventive means 34, 34 is
 fixed. In such a case, therefore, the space between the adjacent slip
 preventive means is included as the "width of the fixed portion".
 The width W3 of the slip preventive means shown in FIG. 2 is preferably 30
 to 80 mm. In case the sanitary napkin is of the type having wings
 including flaps extending to the longitudinal opposite sides thereof, it
 is likewise preferred that the slip preventive means 34 is provided on the
 leakage-preventive layer 3 about the fixed portion. The slip-preventive
 means 34 may be provided on a wing fixing portion which is provided on the
 backsheet side of the wing portions. This width (a space between an
 external and an external of the spread flaps prior to be worn) is the
 "width of the portion to be fixed", i.e., the width W3. In this case, the
 width W3 is preferably 100 to 180 mm.
 In order to erect the free edge portions 22 in a more favorable fashion, as
 shown in FIGS. 1 and 2, groove portions 26 are formed in the opposite left
 and right side edges on the opposite left and right side portions of the
 fixed portion 21. The depth D of each groove portion 26 is preferably 0.1
 to 5 mm. The width W4 of each groove portion 26 is preferably 0.1 to 5 mm.
 As shown in FIG. 1, each groove portion 26 including the side edge of the
 fixed portion 21 is formed into a configuration similar to an outer
 peripheral configuration of the sanitary napkin 1. On the side edge sides
 of the fixed portion 21, the fixed portion 21 and the free edge portions
 22 are divided by the groove portion 26.
 Owing to a provision of the groove portions 26, a body fluid is more
 effectively prevented from dispersing and the groove portions 26 also act
 as flexible axes to make it easier for the free edge portions to be
 erected upwardly.
 The material, etc. of each member constituting the sanitary napkin will be
 described next.
 As a material of the topsheet 23, there is no particular limitation in as
 much as the material is usually used as the topsheet of an absorbent
 article such as a sanitary napkin, or the like. For example, the desired
 material includes a nonwoven fabric composed of a synthetic fiber, such as
 polyethylene fiber, polypropylene fiber polyester fiber,
 polyethylene/polypropylene conjugate fiber, polyethylene. polypropylene
 conjugate fiber, an apertured film obtained by aperturing such film as
 polyethylene, or the like. Among all, apertured nonwoven fabric, apertured
 polyethylene film, or the like which is subjected to aperturing treatment
 in order to enhance absorption is particularly preferable in view of
 absorption.
 As a material of the absorbent member 24, an absorbent sheet and a polymer
 sheet can be listed. The thickness of the absorbent member 24 is
 preferably 0.3 to 5 mm.
 As such an absorbent sheet and a polymer sheet, one usually used as an
 absorbent article such as a sanitary napkin can be used without any
 particular limitation.
 The absorbent sheet particularly preferably used in the present invention
 can be absorbent paper nonwoven fabric, a pulp sheet made of fibers and a
 binder, or the like. The polymer sheet can be a sheet made of a mixture of
 fluff pulp and fiber With a superabsorbent polymer. The sheet made of a
 mixture of fiber and a superabsorbent polymer may be a superabsorbent
 polymer in the sheet dispersed either in layers or in three dimensions.
 A material for forming the absorbent sheet and a fiber used in the polymer
 sheet preferably includes cellulose fiber, such as wood pulp; regenerated
 cellulose fiber, such as viscous rayon and cuprammonium rayon, synthetic
 hydrophilic fiber, such as polyvinyl alcohol fiber and polyacrylonitrile
 fiber, and synthetic fiber with the surface thereof rendered hydrophilic
 with a surface active agent, etc. such as polyethylene fiber,
 polypropylene fiber, polyethylene terephthalate fiber.
 polyethylene/polypropylene conjugate fiber, and polyethylene/polyethylene
 terephthalate conjugate fiber. Cellulose fibers are preferred for their
 satisfactory retention of hydrophilic properties.
 The superabsorbent polymer which can be used in the polymer sheet is
 preferably the one capable of absorbing and retaining 20 or more times as
 much liquid as its own weight and gelling upon liquid absorption. Such
 superabsorbent polymers include starch, crosslinked carboxymethylated
 cellulose, polyacrylic acid or a salt thereof, and a polyacrylic acid salt
 graft polymer. The polyacrylic acid salt is preferably sodium
 polyacrylate. Acrylic acid copolymers containing a comonomer, such as
 maleic acid, itaconic acid, acrylamide,
 2-acrylamide-2-methylpropanesulfonic acid, 2-(meth)acryloylethanesulfonic
 acid, 2-hydroxyethyl (meth)acrylate or styrenesulfonic acid, in such a
 proportion that does not impair its performance as a superabsorbent
 polymer, can also be preferably used.
 It is particularly preferable to use superabsorbent polymers capable of
 absorbing and retaining a large quantity of liquid through ionic osmosis
 and yet having no leaks even under pressure, comprising water-insoluble
 and hydrophilic crosslinked polymer particles which are obtained by
 polymerizing acrylic acid or an alkali salt thereof (e.g. sodium or
 potassium), etc. followed by crosslinking for water insolubilization.
 A preferred polymer sheet among the above-mentioned polymer sheets is the
 one made up of a hydrophilic fiber, a thermally fusible bonding fiber or a
 strengthening assistant, and a superabsorbent polymer. The superabsorbent
 polymer is not present on the absorbent surface of the polymer sheet for
 absorbing liquid but distributed inside the polymer sheet, and adhered to
 the hydrophilic fiber constituting the polymer sheet and hardened. The
 superabsorbent polymer is spread in an amount of 5 to 300 g/m2 of the
 polymer sheet and the polymer sheet has a thickness of 0.3 to 1.5 mm.
 In such a polymer sheet, since a superabsorbent polymer is fixedly
 dispersed in a single sheet in a three-dimensional pattern, the absorption
 ability of the superabsorbent polymer is effectively exhibited. Moreover,
 the gel blocking of the superabsorbent polymer is less. Accordingly, a
 body fluid tends to pass through the absorbent sheet smoothly. Thus, the
 absorbent sheet can advantageously be used in order to obtain a high
 absorption ability.
 In the present invention, from a view point of high absorption ability of
 body fluid, the polymer sheet is preferably used. Also, the absorbent
 sheet and the polymer sheet overlaid one upon the other in superimposed
 relation may be used. When they are overlaid, the polymer sheet is
 preferably located on the lower layer side, i.e., leakage-preventive layer
 3 side.
 As the liquid-permeable sheet 31 forming the leakage-preventive layer 3,
 the leakage-preventive sheet 32 and the absorbent sheet as the absorptive
 portion 33, the elastic member 25, an adhesive agent 4 for fixing the
 absorbent layer 2 and the leakage-preventive layer 3, and a viscous agent
 forming the slip-preventive means 34, those usually used in an absorbent
 article such as a sanitary napkin can be used without any particular
 limitation.
 In the sanitary napkin 1 thus constructed according to this embodiment,
 when in use, the leakage-preventive layer 3 is attached to an undergarment
 such as the shorts through the slip-preventive means 34. And, as
 previously mentioned, the absorbent layer 2 is not fixed directly to the
 undergarment but only through the leakage-preventive layer 3 Accordingly,
 when the wearer moves, the leakage-preventive layer 3 moves in obedient to
 the motion of the undergarment but the opposite left and right free edge
 portions 22 of the absorbent layer 2 do not move directly in obedient
 thereto. Thus, the effect from the motion of the wearer is less.
 Accordingly, the absorbent layer 2 is not easily slipped and a nice
 fitness can be obtained. Moreover, since the absorbent member 24 is
 situated up to the side edges of the absorbent layer 2 and there is a
 provision of the elastic member, the absorbent layer 2 can be retained
 normally in a nicely fitted state to the wearer's body. Since no gap is
 formed and the menses can be absorbed, leakage from the sides can be
 prevented particularly effectively.
 According to the sanitary napkin 1 of this embodiment, even if a discharged
 body fluid migrates widthwise sidewardly beyond or passing through the
 free edge portions 22 of the absorbent layer 2, leakage from the sides can
 effectively prevented by the leakage-preventive layer 3 located outside of
 the free edge portions 22. Particularly, in case the width of the
 slip-preventive means 34 is set larger than the width of the fixed portion
 21, the leakage-preventive layer 3 moves in obedience with the motion of
 the undergarment and fully covers the lower surface of the absorbent
 layer, and therefore, particularly effective.
 Furthermore, in the construction of this embodiment, in case the present
 invention is applied to an absorbent article such as a disposable diaper,
 an incontinent pad, or the like in which a large quantity of body fluid is
 discharged, there can easily be employed such a suitable countermeasure as
 that the absorbent portion 33 in the leakage-preventive layer 3 contains
 the superabsorbent polymer.
 The sanitary napkin according to this embodiment can be manufactured by
 forming the absorbent layer 2 and the leakage-preventive layer 3 in
 accordance with the normal procedure and thereafter, affixing them using
 the adhesive agent 4. The layers 2 and 3 may be affixed at the same time
 the groove portion is formed. In the alternative, after the groove portion
 is formed, the absorbent layer 2 formed with the groove portion may be
 fixed to the leakage-preventive layer 3.
 Another embodiment of an absorbent article of the present invention will
 now be described with reference to FIG. 3.
 Here, FIG. 3 is a perspective view showing another embodiment of an
 absorbent article of the present invention.
 In the sanitary napkin 1 according to the second embodiment shown in FIG. 3
 the configuration of the groove portions 26 is linear. The remaining
 construction is the same as the first embodiment. Although, there is no
 provision of the second absorbent member, this may be provided, where
 necessary.
 As discussed, the configuration of the groove portions 26 is not
 particularly limited but can be selected as desired.
 Since a sectional view taken on line II--II of the sanitary napkin shown in
 FIG. 3 is the same as FIG. 2, an illustration thereof is omitted.
 In the first and second embodiments, the fixed portion and the free edge
 portions are formed from a single absorbent member and a single topsheet,
 respectively. Other examples, in which the fixed portion and the free edge
 portions are formed from separately formed two or more absorbent members,
 will now be described with reference to FIGS. 4 to 7.
 Here, FIGS. 4 to 7 are sectional perspective views showing other
 embodiments of an absorbent article of the present invention, respectively
 (perspective views showing the state taken in a widthwise direction at its
 longitudinal, central portion of the absorbent article).
 In the description to follow, the component members identical or similar to
 those of the first embodiment are denoted by identical reference numerals
 plus 100, respectively and only those points different from the first
 embodiment are particularly described. The points not particularly
 described are the same as the first embodiment.
 In a sanitary napkin 101 according to the third embodiment shown in FIG. 4,
 a fixed portion 121 comprises a fixed portion topsheet 123A provided in
 such a manner as to cover the outer surface side of the fixed portion
 absorbent member 124A. The free edge portions 122 each comprise a free
 edge portion topsheet 123B provided in such a manner as to cover the outer
 surface of the free edge portion absorbent member 124B. The free edge
 portions 122 are firmly secured at basal end portions 122b thereof to
 opposite left and right side portions of the fixed portion 121.
 More specifically, in this embodiment, the leakage-preventive layer 103
 comprises only a leakage-preventive sheet 132.
 The fixed portion absorbent member 124A exhibits a rectangular
 configuration (not shown) and is provided on a widthwise central portion
 of the sanitary napkin. The fixed portion topsheet 123A is provided in
 such a manner as to cover the outer surface side and the side surfaces
 side of the fixed portion absorbent member 124A and also cover the
 widthwise entire surface of the leakage-preventive sheet 103.
 Each free edge portion 122 comprises a free edge portion topsheet 123B
 provided in such a manner as to cover the outer surface of a strip-shaped
 free edge portion absorbent member 124B. The free edge portions 122 are
 fixed to the fixed portion 121 by heat sealing basal end portions 122b
 contacted by opposite side edges 123B' to side edge portions 121b (where
 the fixed portion absorbent member 124A is not present but only the fixed
 portion topsheet 123A is present) of the fixed portion 121. The free edge
 portions 122 are also integral with the leakage-preventive layer 103.
 The free edge portions 122 are folded back widthwise outwardly of the
 sanitary napkin 101 at its part adjacent to the fixed portion absorbent
 member 124A on the basal end portions 122b side.
 The elastic member 125 is provided on the back surface side of the free
 edge portion absorbent member 124B at the free ends 122a of the free edge
 portions 122.
 The width W2' of those portions of the free edge portions 122 which are
 folded back and erected is preferably 5 to 30 mm, and the width W1' of the
 central portion 121a (where the fixed portion absorbent member 124A is
 provided) of the fixed portion 121 is preferably 15 to 60 mm. The width
 W1' of the central portion 121a is smaller than the width W3' of the
 sanitary napkin fixed by the slip-preventive means 134.
 As the fixed portion absorbent member 124A, the fixed portion topsheet 123
 A, the free edge portion absorbent member 124B, the free edge portion
 topsheet 123B, the leakage-preventive sheet 132, etc., the absorbent
 member, the top sheet, the leakage-preventive sheet, etc. which were
 described in detail in the first embodiment may be used without any
 particular limitation.
 Also in the sanitary napkin 101 thus constructed according to this
 embodiment, the absorbent article can be fixed in use to the undergarment
 as in the same manner as the first embodiment and the leakage-preventive
 layer likewise moves in obedient to the motion of the undergarment but the
 free edge portions (particularly the erected portions) do not move
 directly in obedience to the motion of the undergarment, and the same
 effects can be exhibited. The sanitary napkin 101 according to this
 embodiment can be manufactured by forming the fixed portion 121 by fixing
 the fixed portion absorbent member 124A and the fixed portion topsheet
 123A to the leakage-preventive layer 103 comprising the leakage-preventive
 sheet 132 using an adhesive agent, or the like, and then fixing the free
 edge portions 122 to the fixed portion 121 by heat sealing.
 An absorbent article according to the fourth to sixth embodiment shown in
 FIGS. 5 to 7 will now be described. In the description to follow, those
 points different from the third embodiment are particularly described in
 detail. The points not particularly described are the same as the third
 embodiment.
 In the sanitary napkin 101 according to the fourth embodiment shown in FIG.
 5, the basal end portions 122b of the free edge portions 122 are firmly
 secured to the fixed portion 121.
 More specifically, in this embodiment, the free edge portions 122 are fixed
 to the fixed portion 121 by heat sealing the basal end portions 122b
 contacted by the opposite side edges 123B' of the free edge portion
 topsheet 123B to side edge portions of that portion of the fixed portion
 121 where the fixed portion absorbent member 124A is present.
 The free edge portions 122 are folded back widthwise outwardly on the basal
 end portion 122b side.
 In the sanitary napkin 101 according to the fifth embodiment shown in FIG.
 6, the free edge portions 122 are firmly secured at intermediate portions
 122C thereof to the fixed portion 121.
 More specifically, in this embodiment, the free edge portions 122 are such
 that the basal end portions 122b contacted by the opposite side edges
 123B' of the free edge portion topsheet 123B are located on the side edge
 portions 121b (where the fixed portion absorbent member 124A is not
 present but only the fixed portion topsheet 123A is present) of the fixed
 portion 121, and the free ends 122a are located above the side edge
 portions in such a manner as to cover the side surfaces and the outer
 surface side of the side edge portions of the fixed portion absorbent
 member 124A. The free edge portions 122 are firmly secured to the fixed
 portion 121 by heat sealing such that groove portions 126 are formed in
 the intermediate portions 122C of the free edge portions 122, i.e., those
 portions of the fixed portion absorbent member 124A which are located on
 the outer surface side of the side edge portions.
 The free edge portions 122 are folded back widthwise outwardly of the
 sanitary napkin on the center side in the intermediate portions 122C.
 In the sanitary napkin 101 according to the sixth embodiment shown in FIG.
 7, the free edge portions 122 firmly secured at the basal end portions
 122b thereof to the fixed portion 121.
 More specifically, in this embodiment, the free edge portion is 122 are not
 folded back but are erected upwardly above the fixed portion absorbent
 member 124A.
 Also in those fourth to sixth embodiments, the absorbent article can be
 used in the same manner as the third embodiment, and the same functions
 and effects can be exhibited.
 Further embodiments of the present invention will be described hereinafter
 in more detail with reference to the drawings.
 Here, FIG. 8 is a perspective view showing a sanitary napkin as the seventh
 embodiment of the absorbent article of the present invention, FIG. 9 is a
 sectional view taken on line II--II of the sanitary napkin shown in FIG.
 8, FIG. 10 is a sectional view taken on line III--III of the sanitary
 napkin shown in FIG. 8, and FIG. 11 is a schematic view showing a state of
 used of the sanitary napkin shown in FIG. 8.
 In the description to follow, those points different from the first
 embodiment are particularly described. The points not particularly
 described are the same as the first embodiment, and the same functions and
 same effects can be exhibited.
 As shown in FIG. 8, a sanitary napkin 201 as the absorbent article of this
 embodiment includes a liquid-impermeable leakage-preventive layer 203, and
 a liquid-retentive absorbent layer 202 provided above the
 leakage-preventive layer 203. This napkin 201 is formed substantially in a
 vertically long configuration.
 In the sanitary napkin 201 according to this embodiment, as shown in FIGS.
 8 to 10, the absorbent layer 202 includes a liquid-retentive absorbent
 member 221, and a liquid-permeable topsheet 222 provided in such a manner
 as to cover an entire surface (skin contacting surface side and back
 surface side) of the absorbent member 221. On the absorbent layer 202, a
 fixed portion 220a formed by fixing a longitudinal central portion 202a of
 the absorbent layer to the leakage-preventive layer 203, and a rear free
 edge portion 223 where the leakage-preventive layer 203 is not fixed are
 formed. An elastic member 204 is disposed at least on the rear edge
 portion 223 over a predetermined length along the longitudinal direction
 of the absorbent member 221, such that the rear free edge portion 223 is
 erected upwardly of the leakage-preventive layer 203 by contraction of the
 elastic member 204.
 More specifically, in the sanitary napkin 1 according to this embodiment,
 as shown in FIGS. 8 to 10, only the central portion 202a is firmly secured
 to the leakage-preventive layer 203, and a front fee edge portion 226 is
 formed thereon together with the rear free edge portion 223. An elastic
 member 204 is disposed on the front free edge portion 226, so that the
 front free edge portion 226 is erected upwardly of the leakage-preventive
 layer 203 by contraction of the elastic member 204.
 A left free edge portion 224 and a right free edge portion 225 are formed
 on opposite left and right sides of the central portion 202a,
 respectively. The elastic members 204 are disposed on the left free edge
 portion 224 and the right free edge portion 225 over a predetermined
 length along the longitudinal direction of the absorbent member 221, so
 that the elastic members 204 are erected upwardly of the
 leakage-preventive layer 203.
 In this way, the front free edge portion 226, the rear free edge portion
 223, the left free edge portion 224, and the right free edge portion 225
 are formed, such that they are erected upwardly under the effect of the
 elastic member. As a consequence, the absorbent layer 202 is curved to
 exhibit a cup-like configuration as a whole.
 In order to erect the front, rear, left, and right free edge portions 226,
 223, 224, 225 in the absorbent layer 202 in a more favorable fashion so
 that a cup-like configuration having a nice fitness can be formed, as
 shown in FIG. 8, a groove portion 206 is formed in the absorbent layer
 202. Within the groove portion 206, a second absorbent member 227 is
 placed on the absorbent member 221, thereby forming a cubic configuration.
 As shown in FIGS. 9 and 10, the leakage-preventive layer 203 comprises a
 liquid-permeable sheet 232, a leakage-preventive sheet 231, and an
 absorbent sheet 233 interposed therebetween.
 As shown in FIGS. 8 to 10, the elastic members 204 are disposed on the
 opposite left and right side edges in the longitudinal direction of the
 absorbent layer along the edge portion of the absorbent member 221. The
 elastic members 204 are covered with the topsheet 222 and bonded to the
 topsheet through an adhesive agent (not shown). The length of each elastic
 member 204 is preferably 40 to 90 when the length of the absorbent layer
 is set to 100.
 It should be noted that the terms "front", "left", "right", and "rear" are
 used for the sake of convenience in this specification, and those words
 are not intended to define the direction of attachment unless particularly
 defined otherwise.
 The width W1 of the absorbent layer is preferably 30 to 100 mm, and the
 length L1 thereof is preferably 150 to 350 mm.
 The longitudinal curvature (radius of curvature) of the absorbent layer 202
 is preferably 60 to 250 mm, and the widthwise curvature (radius of
 curvature) thereof is preferably 30 to 100 mm. This radius of curvature
 can be obtained as follows.
 [How to Obtain the Radius of Curvature]
 A circular arc A shown in FIG. 15A has a curvature =1/radius of curvature
 (r). The radius of curvature (r) is expressed by the following equation 1
 in accordance with the third power theorem.
EQU (r-h).sup.2 +a.sup.2 =r.sup.2 1
 If the equation 1 is developed, the following equation 2 can be obtained.
EQU r=(h.sup.2 +a.sup.2 /2h 2
 Thus, as shown in FIG. 15B, regarding the napkin as a whole as a circular
 arc A, a height h (distance from a point (p) of contact between the napkin
 and a table when the napkin was placed on the table such that opposite
 ends of the napkin become same in height to the opposite ends) of the
 erected portion of the napkin from a bottom surface of the napkin and a
 representing a half of an apparent length of the curved napkin were
 measured, and the h and the a were entered into the equation 2 thereby
 obtaining a radius of curvature. Specifically, the sanitary napkin was
 placed under a stressless condition, and the height h from the
 longitudinal (widthwise direction) opposite ends to a lowermost point p
 was obtained. Also, a linear distance (2a) between the opposite end
 portions of the napkin was obtained to calculate a. The h and a thus
 obtained were entered into the above equation 2 thereby obtaining the
 radius of curvature r of the sanitary napkin.
 The width W2 of the left free edge portion 224 and the width W3 of the
 right free edge portion are preferably 5 to 30 mm, and the length L2 of
 the front free edge portion 226 and the length L3 of the rear free edge
 portion 223 are preferably 30 to 150 mm.
 The sanitary napkin according to this embodiment can be used in the same
 manner as the generally known sanitary napkin for night use, or the like.
 Since the sanitary napkin 201 according to this embodiment is constructed
 in the manner as mentioned above, since the front, rear, left, and right
 free edge portions 227, 223, 224, and 225 in the absorbent layer 202 are
 curved/moved in obedience to the motion of the body of the wearer so as to
 be nicely fitted to the body as shown in FIG. 11, irrespective of what
 kinds of shorts are in wear, for example, even in wear of a loose shorts
 and motion of the body of the weaer' body, a high fitness can be obtained
 and leakage hardly occurs.
 The eighth embodiment according to the absorbent article of the present
 invention will be described hereinafter with reference to FIGS. 12 to 14.
 Here, FIG. 12 is a perspective view showing a sanitary napkin as the eighth
 embodiment of the absorbent article of the present invention, FIG. 13 is a
 sectional view taken on line VI--VI of the sanitary napkin shown in FIG.
 12, and FIG. 14 is a sectional view taken on line VII--VII of the sanitary
 napkin shown in FIG. 12.
 The points not particularly described in detail are the same as the first
 to seventh embodiments.
 In a sanitary napkin 201 according to this embodiment shown in FIGS. 12 to
 14, the absorbent layer 202 includes a liquid retentive absorbent member
 221, and a liquid-permeable topsheet 222 provided in such a manner as to
 cover at least a skin contacting surface side of the absorbent member 221.
 The longitudinal central portion 202a of the absorbent layer 202 is fixed
 to the leakage-preventive layer 203, and a rear free edge portion 223,
 which is not fixed to the leakage-preventive layer 203, is formed thereon.
 An elastic member 204 is disposed on the rear free edge portion 223 over a
 predetermined length along the longitudinal direction of the absorbent
 member 221, so that the rear free edge portion 223 is erected upwardly of
 the leakage-preventive layer 203 by contraction of the elastic member 204.
 More specifically, in the sanitary napkin 201 according to this embodiment
 is a so-called night-use sanitary napkin, in which the length of the
 sanitary napkin itself is long (length: 250 to 400 mm), and the rear
 portion (the portion located on the back side of the wearer when in wear)
 is widthwise enlarged in a sector-like configuration.
 In the absorbent layer 202, that portion of the absorbent layer 202 which
 is fixed to the leakage-preventive layer 203, is defined as a central
 portion 202a and a front portion 227', and the rear free edge portion 223
 is not fixed to the leakage-preventive layer 203 and thus erectable.
 The rear free edge portion 223 is provided with a second absorbent member
 221a such that a widthwise central portion of the rear free edge portion
 223 is raised (to form a three-dimensional configuration). The second
 absorbent member 221a is disposed between the absorbent member 221 and the
 topsheet 222.
 Elastic members 204 are arranged on opposite left and right side edge
 portions of the rear free edge portion 223 along the side edges of the
 absorbent member 221 and in such a manner as to be covered with the
 topsheet 222.
 Adhesive agent is applied to the back surface side of the opposite left and
 right sides of a front part of the leakage-preventive layer 203 to thereby
 provide one pair of wing portions 27 each provided with a slip-preventive
 portion 271. In this embodiment, the wing portions 207 like other parts of
 the leakage-preventive layer 203 are formed of a liquid-permeable sheet
 232, a leakage-preventive sheet 231, and an absorbent sheet 233 interposed
 therebetween. It is also acceptable that instead of providing the
 absorbent sheet 233, the liquid-permeable sheet 232 and the
 leakage-preventive sheet 231 are bonded together.
 The length L1 of the absorbent layer 202 is preferably 230 to 400 mm, and
 the length L2 of the rear free edge portion 223 is preferably 50 to 200
 mm. In other words, the rear free edge portion 223 refers to the part of
 the absorbent layer 2 which has a predetermined length from the rear end
 of the absorbent layer 2.
 On the opposite left and right side edge portions of the absorbent layer
 202 at the front portion 227' and the central portion 202a, the topsheet
 222 and the absorbent member 221 are integrally folded in superimposed
 relation and leakage-preventive walls 228 are formed.
 Also in the sanitary napkin thus constructed according to this embodiment,
 the same effects as the sanitary napkin according to the first and seven
 embodiments can be exhibited.
 The sanitary napkin according to this embodiment can also be manufactured
 in the same manner as the sanitary napkin according to the seventh
 embodiment.
 An absorbent article according to the present invention is not limited to
 the above embodiments, and many changes and modifications can be made
 without departing from the gist of the present invention.
 For example, in the first embodiment, the leakage-preventive layer 3 made
 be formed of only the leakage-preventive sheet 32 (there is no need of a
 provision of the liquid-permeable sheet 31 and the absorptive portion 33).
 The absorbent member 24 is not necessarily disposed over a widthwise entire
 area of the free edge portion 22. For example, it is acceptable that the
 elastic members 25 are provided on edge ends of the free edge portions 22,
 and the absorbent member 24 is present only up to a widthwise generally
 central portion of each free edge portion 22.
 The elastic member 25 is not necessarily provided on the free end 22a only
 if the free edge portion 22 can be erected, and the member 25 may be
 disposed on a widthwise central portion of the free edge portion.
 The fixed portion 21 may be fixed not only by adhesive agent but also by
 heat sealing, supersonic sealing, or the like. In the fixed portion 21,
 the bonding area (fixing area) between the absorbent layer 2 and the
 leakage-preventive layer 3 is, for example, the opposite left and right
 side edge portions and the longitudinal opposite end edges of the fixed
 portion 21 in the above-mentioned embodiments. However, the fixing area
 may be the entire surface of the fixed portion.
 For example, in the eighth embodiment, the elastic members may be provided
 on the widthwise opposite left and right end portions of the absorbent
 article and the left and right free edge portions may be erected upwardly
 as in the seventh embodiment. It is also accepted that the second
 absorbent member 202a exhibits an elongate configuration extending to the
 rear portion, and the absorbent member is raised so that it fits nicely to
 the body of the wearer from the discharging portion to the groove portion
 of the hip.
 In the eighth embodiment, the second absorbent member 221a is disposed
 between the absorbent member 221 and the topsheet 222. However, the second
 absorbent member 221a may be disposed between the adjacent layers of the
 absorbent member 221.