JP2020089669A - Absorbent article - Google Patents

Abstract

To provide an absorbent article which keeps adhesion to a wearer by reducing disconnection of an elastic member exerting shrinkage force from a sheet member, in a disposable diaper.SOLUTION: In the absorbent article of this invention, the elastic member is bonded to the sheet member with a responsive urethane hot-melt adhesive.SELECTED DRAWING: Figure 3

Description

TECHNICAL FIELD The present invention relates to an absorbent article, and particularly to a technique for joining elastic members constituting a disposable diaper.

Elastic members such as polyurethane threads are used for the waist, legs, and three-dimensional gathers of the disposable diaper. The three-dimensional gather uses the contracting force of the elastic member to erect the non-woven fabric on the side of the wearer and prevent urine excreted by the wearer from leaking sideways. The leg elastic members are disposed on the leg side edges of the crotch portion of the disposable diaper, and the contracting force of the leg elastic members brings the both side edges of the crotch into close contact with the wearer's thigh. The waist elastic members are disposed at the front and rear longitudinal ends of the disposable diaper. When the wearer wears the disposable diaper, the contraction force of the waist elastic member causes the front part and the back part of the diaper to be in close contact with the wearer's waist. By disposing the elastic members for the legs and the elastic members for the waist around the disposable diaper, the disposable diaper is brought into close contact with the wearer, so that leakage of excrement can be reduced.

For example, in Patent Document 1, the first sheet is joined to the first sheet and the second sheet by a foaming hot-melt adhesive between the first sheet and the second sheet, and is contracted by the first sheet. The invention of an elastic sheet, which is a part of an absorbent article, characterized in that it comprises an elastic member that contracts the portion and the second sheet portion. The foamed hot melt adhesive is an ordinary hot melt adhesive mixed with gas (see Patent Document 1 (Claim 1, paragraph 0014 and paragraph 0022)).

JP, 2008-245960, A

Generally, the elastic member is attached to the sheet member constituting the absorbent article with a hot melt adhesive in a state where the elastic member is stretched beyond its natural length. However, the contracting force of the elastic member to return to the natural length acts so that the elastic member is separated from the sheet member. Therefore, there is a problem that the elastic member comes off the sheet member. The hot melt adhesive that joins the elastic member to the sheet member is softened by heating. When the wearer of the absorbent article uses the heater, the hot melt adhesive softens. When the hot melt adhesive softens, the elastic member comes off the sheet and returns to its natural length, and the contracting force of the elastic member cannot be used. Therefore, there is a problem in that the adhesiveness of the absorbent article to the wearer is reduced and excrement easily leaks from the absorbent article.

The present invention has been made in view of the above problems, in the absorbent article, the elastic member expressing the contraction force, by reducing the deviation from the sheet member, the adhesion to the wearer. An object is to provide an absorbent article that is maintained.

The absorbent article of the present invention has an elastic member and a sheet member, and the elastic member is joined to the sheet member by a cured product of a reactive urethane hot melt adhesive. The reactive urethane hot melt adhesive used in the present invention has a highly reactive isocyanate group. The isocyanate group can react with a surface functional group (for example, a hydroxyl group or a carboxyl group) of the object to be adhered to form a chemical bond, and the interfacial adhesion strength to the object to be adhered is increased. Further, the reactive urethane hot melt adhesive reacts with moisture in the air to form a three-dimensional crosslink and cure. The cured product of the reactive urethane hot melt adhesive is not plasticized by heating. Therefore, even when the wearer uses a heating appliance, the cured product of the reactive urethane hot melt adhesive joining the sheet member and the elastic member does not soften, and the elastic member is prevented from coming off the sheet member. To be done.

The elastic member preferably has a thread shape or a band shape. The material of the elastic member is preferably polyurethane or natural rubber.

The elastic member is preferably joined to the sheet member at a stretch ratio of 1.1 to 5.0 times the natural length.

A preferred example of the absorbent article of the present invention is a disposable diaper, and examples of the elastic member include waist elastic members, leg elastic members, waist elastic members, or three-dimensional gather elastic members. be able to.

ADVANTAGE OF THE INVENTION According to this invention, in an absorbent article, the elastic member which has been expressing the contraction force is reduced from slipping off from the sheet member, so that the absorbent article in which the adhesion to the wearer is maintained is obtained. .. Further, according to the present invention, the elastic member is prevented from coming off the sheet member even when the wearer uses the heating appliance.

The top view which looked at an example of the disposable diaper of the present invention from the top sheet side. The top view which looked at the disposable diaper of FIG. 1 from the back sheet side. The typical sectional view of the III-III line of FIG. The top view which looked at an example of the disposable diaper of the present invention from the top sheet side. FIG. 5 is a schematic cross-sectional view taken along line VV of FIG. 4. FIG. 5 is a schematic sectional view taken along line VI-VI in FIG. 4.

The absorbent article of the present invention has an elastic member and a sheet member, and the elastic member is joined to the sheet member by a cured product of a reactive urethane hot melt adhesive.

(Reactive urethane hot melt adhesive)
First, the reactive urethane hot melt adhesive used in the present invention will be described. The reactive urethane hot melt adhesive used in the present invention has a highly reactive isocyanate group. The isocyanate group can react with a surface functional group (for example, a hydroxyl group or a carboxyl group) that the absorbent article and the elastic member have to form a chemical bond, and the interfacial adhesion strength to the absorbent article and the elastic member becomes high. The reactive urethane hot melt adhesive is a moisture-curable adhesive that reacts with moisture in the air to form a three-dimensional crosslink and cure. The cured product of the reactive urethane hot melt adhesive has a three-dimensional crosslinked structure and is very excellent in heat resistance and water resistance. Further, the reactive urethane hot melt adhesive can be applied in a molten state similarly to the conventional hot melt adhesive, and the adherends can be temporarily joined by cooling and solidifying. Therefore, if the reactive urethane hot melt adhesive is used, the conventional manufacturing equipment can be used, and the reduction in productivity can be suppressed. The reactive urethane hot melt adhesive preferably contains a urethane prepolymer having an isocyanate group at the end of the molecular chain.

It is preferable that the urethane prepolymer is obtained by reacting a polyol and a polyisocyanate under conditions such that an isocyanate group becomes excessive.

The polyol is not particularly limited, but examples thereof include polyether polyol, polyester polyol, polycarbonate polyol, and polycaprolactone.

The polyisocyanate is a compound having at least two isocyanate groups in the molecule. Examples of the polyisocyanate include yellowing type diisocyanates such as diphenylmethane diisocyanate, dimethyldiphenylmethane diisocyanate, tolylene diisocyanate, and phenylene diisocyanate; and non-yellowing diisocyanates such as hexamethylene diisocyanate, dicyclohexylmethane diisocyanate, xylylene diisocyanate, and isophorone diisocyanate, or difficult. A yellowing diisocyanate can be mentioned. The reactive urethane hot melt adhesive used in the present invention preferably contains a non-yellowing diisocyanate or a hardly yellowing diisocyanate as a polyisocyanate component.

The content of the isocyanate group of the reactive urethane hot melt adhesive used in the present invention is preferably 0.5% by mass or more, more preferably 0.7% by mass or more, and further preferably 1.0% by mass or more. 15 mass% or less is preferable, more preferably 10 mass% or less, and further preferably 5 mass% or less. When the content of the isocyanate group is 0.5% by mass or more, moisture curability is easily exhibited, and when the content is 15% by mass or less, the adhesive strength after curing is good.

The melt viscosity of the reactive urethane hot melt adhesive at 120° C. is preferably 2,000 mPa·s or more, more preferably 4,000 mPa·s or more, further preferably 6,000 mPa·s or more, and 20,000 mPa·s. s or less is preferable, 15,000 mPa·s or less is more preferable, and 10,000 mPa·s or less is further preferable. When the melt viscosity of the reactive urethane hot melt adhesive is within the above range, the coatability of the reactive urethane hot melt is good.

The open time of the reactive urethane hot melt adhesive used in the present invention is preferably 10 seconds or longer, more preferably 15 seconds or longer, further preferably 20 seconds or longer, and 60 seconds or shorter. Is preferably 50 seconds or less, more preferably 40 seconds or less. This is because if the open time of the reactive urethane hot melt adhesive is within the above range, the adhesive strength of the joint portion is likely to be improved.

In the present invention, a non-reactive hot melt adhesive may be used together with the reactive urethane hot melt adhesive for joining the elastic member and the sheet member.

(Non-reactive hot melt adhesive)
The non-reactive hot melt adhesive is applied to an object to be adhered in a state of being softened or melted by heating, and exhibits adhesive force by cooling and solidifying at room temperature. Examples of the non-reactive hot melt adhesive include a rubber hot melt adhesive, an olefin hot melt adhesive, a polyamide hot melt adhesive, and a polyester hot melt adhesive.

The rubber-based hot melt adhesive preferably contains a synthetic rubber as a base polymer, and more preferably contains a styrene block copolymer. Examples of the synthetic rubber include butadiene styrene, styrene-acrylonitrile, acrylonitrile-butadiene-styrene, styrene-butadiene rubber, butadiene-styrene elastomer, styrene-isoprene (SI), styrene-isoprene-styrene (SIS), styrene-butadiene. -Styrene (SBS), styrene-ethylene/butylene-styrene (SEBS), and at least one selected from the group consisting of styrene-ethylene/propylene-styrene (SEPS). Among these, as synthetic rubber, styrene-isoprene (SI), styrene-isoprene-styrene (SIS), styrene-butadiene-styrene (SBS), styrene-ethylene/butylene-styrene (SEBS), and styrene-ethylene / At least one selected from the group consisting of propylene-styrene (SEPS) is preferred. The styrene block copolymer may have a linear molecular structure or a radial molecular structure.

The olefin-based hot melt adhesive preferably contains an olefin-based polymer. Examples of the olefin-based polymer include polyolefin, polyolefin copolymer, and olefin/α-olephein interpolymer. Examples of the olefin-based polymer include amorphous, semi-crystalline, and crystalline ones. For example, amorphous polyolefin can be preferably used.

Examples of the olefin polymer include ethylene/vinyl acetate (EVA), ethylene/acrylate, ethylene/methacrylate, ethylene/n-butyl acrylate, ethylene/n-hexyl acrylate, ethylene/propylene, ethylene/butene, ethylene/octene, Examples include polypropylene. The olefin polymers may be used alone or in combination of two or more.

The reactive urethane hot melt adhesive and the non-reactive hot melt adhesive may contain a tackifier, a plasticizer, a wax and the like.

Examples of the tackifier include gum rosin, wood rosin, tall oil rosin, distilled rosin, hydrogenated rosin, dimerized rosin, and polymerized rosin.

Examples of the plasticizer include naphthenic oils, paraffinic oils (for example, cycloparaffin oils), mineral oils, phthalates, adipates, olefin oligomers (for example, oligomers of polypropylene, polybutene and hydrogenated polyisoprene). ), polybutene, polyisoprene, hydrogenated polyisoprene, polybutadiene, benzoic acid ester, animal oil, vegetable oil (for example, castor oil, soybean oil), oil derivative, glycerol ester of fatty acid, polyester, polyether, etc. it can.

Examples of the wax include paraffin wax, microcrystalline wax, polyethylene wax, polypropylene wax, by-product polyethylene wax, Fischer-Tropsch wax, oxidized Fischer-Tropsch wax, and hydroxystearamide wax and fatty amide wax. Base wax and the like can be mentioned.

The reactive urethane hot melt adhesive and the non-reactive hot melt adhesive may further contain additives such as stabilizers, antioxidants, pigments, dyes, and ultraviolet absorbers.

(Absorptive article)
The absorbent article of the present invention has an elastic member and a sheet member, and the elastic member is particularly limited as long as it is joined to the sheet member constituting the absorbent article by a cured product of a reactive urethane hot melt adhesive. Not done. This is because the present invention can be preferably used with an absorbent article having such a configuration. Specific examples of the absorbent article include an absorbent sheet, an absorbent pad, a napkin, an incontinence sheet, and a disposable diaper. Among these, since many elastic members are used, the present invention can be suitably applied to a disposable diaper.

The sheet member used in the present invention is not particularly limited as long as it is a member having a sheet-like form that constitutes an absorbent article. The sheet member may be either a liquid permeable sheet or a liquid impermeable sheet. Examples of the liquid-permeable sheet include a non-woven fabric formed of hydrophilic fibers and a non-woven fabric formed of hydrophobized hydrophobic fibers. Examples of the hydrophilic fiber include cellulose, rayon, and cotton. Examples of the hydrophobic fiber include polypropylene, polyethylene, polyester and polyamide. Examples of the nonwoven fabric include point bond nonwoven fabric, air-through nonwoven fabric, spunlace nonwoven fabric, spunbond nonwoven fabric, and air-laid nonwoven fabric.

Examples of the liquid-impervious sheet include a water-repellent or liquid-impermeable nonwoven fabric (for example, spunbonded nonwoven fabric, meltblown nonwoven fabric, SMS (spun) formed of hydrophobic fibers (for example, polypropylene, polyethylene, polyester, polyamide). Bond, meltblown, spunbond) non-woven fabric) and water-repellent or liquid-impermeable plastic films can be used.

The basis weight of the nonwoven fabric suitably used as the sheet member is preferably 10 g/m ² or more, more preferably 12 or more, further preferably 13 g/m ² or more, preferably 25 g/m ² or less, and more preferably 22 g/m ² or less. 20 g/m ² or less is more preferable.

As the material of the sheet member, polyethylene, polypropylene, ethylene-propylene copolymer and polyester are preferable.

The sheet member used in the present invention is generally arranged on the skin surface side and/or outer surface side of the absorbent layer described below to form an absorbent article. In the absorbent article of the present invention, the side facing the wearer's skin when worn is the skin surface side, and the back surface on the skin side is the outer surface side.

Examples of the material of the elastic member used in the present invention include polyurethane and natural rubber, with polyurethane being preferred. This is because the affinity with the reactive urethane hot melt adhesive used is high and the adhesive force between the elastic member and the sheet member is further increased. Further, the shape of the elastic member is appropriately selected from a thread shape, a band shape, and a plate shape, but the thread shape is preferable.

When the shape of the elastic member is thread-like, the fineness of the thread-like elastic member is preferably 300 dtex or more, more preferably 400 dtex or more, further preferably 450 dtex or more, 2000 dtex or less, more preferably 1500 dtex or less, further preferably It is 1000 dtex or less. This is because if it is 300 dtex or more, it is difficult for elongation breakage to occur during manufacturing. Also, if it is 2000 dtex or less, the texture becomes good.

The elastic member is preferably joined to the sheet member in a stretched state. This is because it is placed in an absorbent article to exert a contracting force. The stretch ratio when the elastic member is joined is preferably 1.1 times or more, more preferably 1.3 times or more, further preferably 1.5 times or more, and preferably 5.0 times or less, It is preferably 4.0 times or less, more preferably 3.0 times or less. This is because if it is 1.1 times or more, the diaper is less likely to slip. Also, if it is 5.0 times or less, the tightening feeling does not become strong.

In the present invention, the elastic member is joined to the sheet member in a stretched state, for example, at least both ends of the elastic member are joined to the sheet member by a cured product of a reactive urethane hot melt adhesive. Preferably. The reactive urethane hot melt adhesive used in the present invention has high adhesive strength. Therefore, if at least both ends of the elastic member are joined to the sheet member by the cured product of the reactive urethane hot melt adhesive, the elastic member is prevented from peeling from the sheet member. The length at which both ends of the elastic member are joined to the sheet member by the cured product of the reactive urethane hot melt adhesive is preferably within 5.0 cm from both ends of the elastic member, and 2 from both ends of the elastic member. It is more preferably 0.5 cm or less, more preferably 0.5 cm or more from both ends of the elastic member, and more preferably 1.0 cm or more. When the length at which both ends of the elastic member are adhered to the sheet member is within the above range, the adhesive strength is high, and the elastic member is further prevented from coming off the sheet member.

In a preferred aspect of the present invention, the elastic member may be intermittently joined to the sheet member between both ends of the elastic member and a cured product of a reactive urethane hot melt adhesive between the both ends. Further, in the elastic member, only the both ends of the elastic member are joined to the sheet member by the cured product of the reactive urethane hot melt adhesive, and the central portion where the reactive urethane hot melt adhesive is not applied is the non-reactive hot melt. You may make it join to a sheet member with an adhesive agent. Further, only the both ends of the elastic member are joined to the sheet member by the cured product of the reactive urethane hot melt adhesive, and the adhesive is not applied to the central portion where the reactive urethane hot melt adhesive is not applied. It may not be joined to the member.

In another preferred embodiment, the elastic member may be bonded to the sheet member with a cured product of the reactive urethane hot melt adhesive over the entire length.

Further, in a preferred embodiment of the present invention, an elastic sheet in which a thread-like elastic member is processed in advance into a desired shape and joined with a cured product of a reactive urethane hot melt adhesive is prepared, and the elastic sheet is absorbed. You may make it join to another sheet member which comprises an article. The elastic sheet and the other sheet members constituting the absorbent article are preferably joined with a cured product of a reactive urethane hot melt adhesive. At least both ends of the elastic sheet are preferably joined to another sheet member constituting the absorbent article by a cured product of the reactive urethane hot melt adhesive.

The absorbent article of the present invention has an absorbent layer that absorbs liquid. The absorbent layer absorbs and retains excreted liquid excreted by the wearer (for example, water contained in urine and feces). Specifically, the absorbent layer contains a water absorbent resin powder and/or a water absorbent fiber. As the water absorbent resin powder, those conventionally used in absorbent articles can be used. Examples of the water-absorbent resin powder include synthetic polymer-based water-absorbent resin powders such as polyacrylic acid salt-based, polysulfonate-based, maleic anhydride-based, polyacrylamide-based, polyvinyl alcohol-based, polyethylene oxide-based; , Polyglutamic acid-based, polyalginic acid-based, starch-based, and cellulose-based water-absorbent resin powders derived from natural products. Examples of the water absorbing fibers include pulp fibers, cellulose fibers, rayon, acetate fibers and the like. The shape of the absorbent layer in plan view is not particularly limited, and examples thereof include a rectangular shape, an hourglass shape, a gourd shape, and a battledore shape.

In the absorbent article of the present invention, examples of the sheet member include a surface sheet and an exterior sheet that form the absorbent article. The absorption layer is arranged, for example, between the topsheet and the exterior sheet.

(Disposable diapers)
Hereinafter, the absorbent article of the present invention will be described based on a preferred embodiment of a disposable diaper. The disposable diaper has a front portion, a crotch portion, and a rear portion. It is preferable that the disposable diaper has an hourglass shape that extends in the vertical direction from the front portion to the rear portion and is narrowed in the width direction at the crotch portion located in the middle. The front part is applied to the wearer's ventral side, the back part is applied to the wearer's back side, and the crotch part is applied to the wearer's inseam. In the disposable diaper of the present invention, the side facing the wearer's skin when worn is the skin surface side, and the back surface on the skin side is the outer surface side.

Examples of the sheet member that constitutes the disposable diaper of the present invention include a surface sheet and an exterior sheet. The surface sheet is a sheet arranged on the surface of the absorbent article on the skin side, and examples thereof include a top sheet and a side sheet. The exterior sheet is a sheet arranged on the outer surface side of the absorbent article, and examples thereof include a back sheet.

In a preferred aspect of the present invention, a plurality of waist elastic members extending in the width direction are provided on the front portion and/or the rear portion of the disposable diaper. The waist elastic member is preferably joined to the sheet member forming the front portion and/or the rear portion by a cured product of a reactive urethane hot melt adhesive in a state where the elastic member is stretched to a length longer than its natural length. The waist elastic member generates a contracting force that contracts the front part and/or the rear part in the width direction. When the wearer wears the disposable diaper, the front part and/or the back part can be fitted around the waist of the wearer by the contracting force of the waist elastic member.

Moreover, in another preferable aspect of the present invention, a plurality of leg elastic members are provided on both side edges of the crotch portion in the width direction. The leg-surrounding elastic member is preferably joined to the sheet member constituting the crotch portion of the disposable diaper by a cured product of a reactive urethane hot melt adhesive in a state where the elastic member for leg circumference is extended from its natural length. The leg elastic members generate a contracting force that contracts both side edges of the crotch part. When the wearer wears the disposable diaper, both side edges of the crotch portion can be fitted to the wearer's thigh due to the contracting force of the elastic member for leg circumference.

In another preferred aspect of the present invention, the waistline elastic member is provided between the waist elastic member and the leg elastic member in the front portion and/or the rear portion of the disposable diaper. The waist elastic member is joined to the sheet member forming the front portion and/or the rear portion by a cured product of the reactive urethane hot melt adhesive in a state where the elastic member for the waist portion is stretched to the natural length. The contraction force of the waistline elastic member improves the adhesion of the disposable diaper around the lower abdomen and the buttocks.

In a preferred aspect of the present invention, a three-dimensional gather is provided along the vertical direction on the skin surface side. Side leakage of urine and feces excreted by the three-dimensional gather is prevented. An elastic member for three-dimensional gathers, which is extended in the front-rear direction, is arranged at a widthwise inner end (an upper end when standing up) of the three-dimensional gathers. The tip of the three-dimensional gather is configured to be able to stand up in the direction away from the top sheet (skin surface side) by the contracting force of the elastic member. It is preferable that the elastic member for three-dimensional gather is joined to the sheet member forming the three-dimensional gather by a cured product of a reactive urethane hot melt adhesive in a state where the elastic member is stretched from its natural length.

Hereinafter, a preferred disposable diaper of the present invention will be described with reference to the drawings, but the present invention is not limited to the embodiment shown in the drawings.

As the disposable diaper of the present invention, for example, a fastening type disposable diaper having an absorbent layer, a surface sheet provided on the skin side of the absorbent layer, and an exterior sheet provided on the outer surface side of the absorbent layer (Aspect 1) ); and a pants-type disposable diaper (Aspect 2) in which an absorbent core having an absorbent layer provided between a liquid-permeable sheet and a liquid-impermeable sheet is provided on the skin side of the exterior sheet. You can

FIG. 1 is a plan view of a disposable diaper 1 according to a preferred embodiment 1 of the present invention when viewed from the topsheet 10 side in an unfolded state. FIG. 2 is a plan view of the disposable diaper 1 viewed from the exterior sheet 20 side in the unfolded state. FIG. 3 is a sectional view of the disposable diaper 1 taken along line III-III in FIG. 1. It should be noted that FIGS. 1 and 2 show a state in which a three-dimensional gather elastic member 41, a waist elastic member 51, and a leg elastic member 52, which will be described later, are all extended. In the figure, arrow A is defined as the vertical direction (front-back direction), and arrow B is defined as the width direction. Further, the direction on the surface formed by the arrows A and B is defined as the plane direction. Further, the vertical direction to the surface formed by the arrows A and B represents the vertical direction C.

As shown in FIGS. 1 to 3, a disposable diaper 1 according to a preferred embodiment 1 is a liquid-permeable top sheet 10, a liquid-impermeable outer sheet 20, and an absorbent layer interposed between the sheets 10 and 20. And a diaper body 2 which is a laminated body having 30.

The diaper body 2 has a front portion 2a that is applied to the wearer's abdominal surface, a rear portion 2b that is applied to the back surface of the wearer, and a crotch portion 2c that connects the front portion 2a and the rear portion 2b. Hereinafter, the direction in which the front portion 2a, the crotch portion 2c, and the rear portion 2b are continuous is referred to as "vertical direction (front-back direction)", and the direction orthogonal to the vertical direction and along the surface of the diaper body 2 is referred to as "width direction". .. The diaper body 2 extends vertically from the front portion 2a to the rear portion 2b, and has a shape that is narrowed in the width direction at a crotch portion 2c located in the middle thereof.

The top sheet 10 is a liquid-permeable sheet arranged on the skin side of the diaper body 2. The top sheet 10 extends in a band shape from the front portion 2a to the rear portion 2b, and the dimension in the width direction thereof is smaller than the dimension in the width direction of the outer edge of the diaper body 2.

The exterior sheet 20 is arranged on the outer surface side of the diaper body 2. The exterior sheet 20 has a shape that is substantially the same as the diaper body 2 in a plan view. That is, the exterior sheet 20 covers the entire lower surface of the diaper body 2.

The absorbent layer 30 is fixed between the top sheet 10 and the exterior sheet 20, and has a liquid absorbing property and a liquid retaining property. As shown in FIG. 3, the absorbent layer 30 is preferably fixed between the top sheet 10 and the exterior sheet 20 with a non-reactive hot melt adhesive 55. The exterior sheet 20 is a laminated sheet including a liquid-impervious sheet 20a and a nonwoven fabric 20b attached to the outer surface of the liquid-impermeable sheet 20a. Further, as shown in FIG. 1, the absorbent layer 30 is formed to be slightly smaller than the outer edge of the diaper body 2 in a plan view.

A pair of side sheets 40 is provided on the upper surface side of the top sheet 10 to prevent lateral leakage of urine. A pair of side sheets are joined. The pair of side sheets 40 extends in the vertical direction (front-rear direction) so as to cover the left and right side edge portions of the diaper body 2.

As shown in FIG. 3, the pair of side sheets 40 are provided on the skin surface side of the top sheet 10 on both sides of the skin surface side of the top sheet 10 along the longitudinal direction (front-rear direction) at intervals in the width direction. It is preferably joined to the part. The side sheet 40 on the inner side in the width direction from the joining point between the side sheet 40 and the top sheet 10 is not joined to the top sheet 10 and is a free end. A plurality of elastic members 41 for three-dimensional gathers, which extend in the front-rear direction, are arranged at the front end of the side seat 40 on the inner side in the width direction. The widthwise inner end of the side seat constitutes a three-dimensional gather. The elastic member 41 for three-dimensional gathers is preferably joined to the side sheet 40 by a cured product 72a of a reactive urethane hot melt adhesive in a state where the elastic member 41 for three-dimensional gathers is extended from its natural length. For this reason, the elastic member 41 for three-dimensional gathers generates a contracting force that contracts the side seat 40 in the vertical direction (front-back direction). When the disposable diaper is opened, the tip end portion of the side seat 40 on the inner side in the width direction rises due to the contracting force of the elastic member 41 for three-dimensional gathers. As a result, a pair of upstanding weirs are formed on the upper surface of the diaper body 2, and the urine excreted by the wearer is prevented from leaking laterally.

In this embodiment, it is preferable that the elastic member 41 for three-dimensional gathers is coated with a reactive urethane hot melt adhesive and attached to the side sheet 40. Further, it is also preferable that only both ends of the elastic member 41 for three-dimensional gathers are joined to the side sheet 40 by the cured product 72a of the reactive urethane hot melt adhesive.

In the aspect shown in FIG. 3, since the width of the top sheet 10 is shorter than the width of the exterior sheet 20 at both side edges of the crotch portion 2c of the disposable diaper, the top sheet 10 is located above both side edges in the width direction of the exterior sheet 20. The top sheet 10 does not exist, but the side sheet 40 is provided. In the disposable diaper according to this aspect, the leg elastic members 52 are provided on the side sheet 40 and the exterior sheet 20 that form the surface sheet along the leg edges of the crotch portion 2c, and the reactive urethane hot melt adhesive is cured. It is joined by the object 72b.

The front portion 2a and the rear portion 2b are provided with a plurality of waist elastic members 51 extending in the width direction. The waist elastic member 51 is joined between the top sheet 10 and the exterior sheet 20 by a cured product of a reactive urethane hot melt adhesive (not shown) in a state where the elastic member 51 is stretched from its natural length. .. Therefore, the waist elastic member 51 generates a contracting force that contracts the front portion 2a and the rear portion 2b in the width direction. When the wearer wears the disposable diaper 1, the front portion 2a and the rear portion 2b can be fitted around the waist of the wearer by the contracting force of the waist elastic member 51.

Further, a plurality of leg elastic members 52 extending in the front-rear direction are provided on both side edges of the crotch portion 2c in the width direction. The leg elastic members 52 are preferably joined to the side sheet 40 and the exterior sheet 20 by a cured product 72b of a reactive urethane hot melt adhesive in a state where the elastic members 52 are stretched beyond their natural length (FIG. 3). Therefore, the leg elastic members 52 generate a contracting force that contracts both side edge portions of the crotch portion 2c in the vertical direction (front-back direction). When the wearer wears the disposable diaper 1, both side edges of the crotch portion 2c can be fitted to the wearer's thigh due to the contracting force of the leg elastic members 52.

In this aspect, for example, a reactive urethane hot melt adhesive is applied to the exterior sheet 20, and the leg-surrounding elastic member 52 is attached in a state of being stretched beyond its natural length. Moreover, it is preferable that the elastic member 52 for the leg circumference is joined by the cured product 72b of the reactive urethane hot melt adhesive between the side sheet 40 and the exterior sheet 20 over the entire length.

For the elastic members 41 for three-dimensional gathers, the elastic members 51 for the waist and the elastic members 52 for the legs, it is preferable to use, for example, polyurethane elastic members. This is because it has a high affinity with the reactive urethane hot melt adhesive used as the adhesive and the adhesive force between the elastic member and the sheet member is further improved. Further, examples of the shape of the elastic member include a thread shape and a band shape (flat plate shape), and it is preferable to use a thread shape elastic member.

The disposable diaper 1 of the embodiment shown in FIG. 1 includes a pair of fastening members 60. Each of the fastening members 60 has a fastening base material 61 and two tongue-shaped knob portions 62 that project outward in the width direction from the free end side edges of the fastening base material 61. A first fastening member 63 is provided on the skin side of each knob portion 62. The fastening base material 61 is sandwiched between the side sheet 40 and the exterior sheet 20 at the fixed end on the inner side in the width direction, and is joined to the diaper body. On the other hand, as shown in FIG. 2, a second fastening member 70 for detachably fastening the first fastening member 63 is provided on the outer surface of the front portion 2a of the diaper body 2.

The fastening base material can be appropriately selected from, for example, non-woven fabric, woven fabric, knitted fabric, and resin film material. As the fastening base material, a nonwoven fabric manufactured by a combination of one or more manufacturing methods of a spunbond method, an air through method, a point bond method, a melt blow method and an air laid method is preferable. Furthermore, basis weight ^{30g / m 2 ~100g / m 2} , spun bond method, or nonwoven fabric produced by a SMS process combining a spunbond method and melt blow method are preferable in terms of strength. As fastening base, most preferred is a nonwoven fabric produced by a spunbond method in basis weight ^{50g / m 2 ~85g / m 2} . The material can be appropriately selected from synthetic fibers such as polypropylene, polyethylene, polyester and polyamide, and natural fibers such as pulp and silk, and preferably synthetic fibers such as polypropylene, polyethylene and polyester can be used. As a fastening base material, a material containing polypropylene or polyester fiber as a main component is suitable because it has high strength. The most preferable material for the fastening base material is polyester fiber.

The first fastening member and the second fastening member are not particularly limited as long as they can be detachably fastened. As a combination of the first fastening member and the second fastening member, for example, a mode in which the first fastening member and the second fastening member constitute a surface fastener; the first fastening member is an adhesive tape, A mode in which the second fastening member is an adhesive sheet to which an adhesive tape can be removably attached can be mentioned. When the surface fastener is adopted, it is preferable to arrange the hook material (male member) on the first fastening member and the loop material (female member) on the second fastening member.

As the first fastening member, for example, a hook material in which a plurality of hooks are densely provided in a planar shape is preferably used. The hook shape of the hook material is preferably an anchor shape, a piece shape, a mushroom shape or the like. Examples of the hook material include "Magic Tape (registered trademark)" (manufactured by Kuraray Co., Ltd.), "Quicklon (registered trademark)" (manufactured by YKK Co.), "Majicross (registered trademark)" (manufactured by Kanebo Bell Touch Co., Ltd.), etc. Commercially available products can be used. As the second fastening member, for example, a loop material (a nonwoven fabric, a woven fabric, a knitted fabric, or a resin film composite material having a nonwoven fabric, a woven fabric or the like on its surface) in which a fine loop structure is densely provided in a planar shape is used. Used.

FIG. 4 is a plan view of the pants-type disposable diaper 1 according to the second preferred embodiment of the present invention when viewed from the topsheet 10 side in an unfolded state. FIG. 5: is sectional drawing cut|disconnected by the VV line of the disposable diaper 1 of FIG. FIG. 6 is a sectional view taken along line VI-VI of the disposable diaper 1 of FIG. It is preferable that the disposable diaper 1 according to a preferred embodiment is formed into a pant shape by joining both side edges of the front part 2a and both side edges of the rear part 2b. Note that description of materials and configurations common to the disposable diaper of the first aspect will be omitted.

A plurality of waist elastic members 51 extending in the width direction are provided on the front portion 2a and the rear portion 2b of the disposable diaper 1 according to the second preferred embodiment of the present invention. The waist elastic member 51 extends between the liquid-impermeable sheet 20a of the exterior sheet 20 and the non-woven fabric 20b bonded to the outer surface of the liquid-impermeable sheet 20a in a state where the elastic member 51 is stretched beyond its natural length. , Are bonded by a cured product 72a of a reactive urethane hot melt adhesive (FIG. 5). Therefore, the waist elastic member 51 generates a contracting force that contracts the front portion 2a and the rear portion 2b in the width direction. When the wearer wears the disposable diaper 1, the front portion 2a and the rear portion 2b can be fitted around the waist of the wearer by the contracting force of the waist elastic member 51.

A plurality of leg elastic members 52 are provided along both edges of the crotch portion 2c of the disposable diaper 1 according to the second preferred embodiment of the present invention in the width direction along both edges of the crotch portion. The leg elastic members 52 are provided so as to cross the crotch portion below the absorbent core in the width direction. Specifically, the left and right leg-surrounding elastic members 52a arranged along the side edge on the front portion 2a side of the crotch portion of FIG. 4 cross the crotch portion 2c in the width direction below the absorbent core 32. Are connected as. Similarly, the left and right leg elastic members 52b arranged along the side edge on the rear portion 2b side of the crotch portion of FIG. 4 cross the crotch portion 2c in the width direction below the absorbent core 32. It is connected. The leg elastic members 52 are arranged between the liquid impermeable sheet 20a of the exterior sheet 20 and the nonwoven fabric 20b bonded to the outer surface side of the liquid impermeable sheet 20a in a state in which the elastic members 52 are stretched to the natural length. , Are bonded by a cured product 72 of a reactive urethane hot melt adhesive (FIGS. 5 and 6). Therefore, the leg elastic members 52 generate a contracting force on both side edge portions of the crotch portion 2c. When the wearer wears the disposable diaper 1, both side edges of the crotch portion 2c can be fitted to the wearer's thigh due to the contracting force of the leg elastic members 52.

In this aspect, for example, a reactive urethane hot melt adhesive is applied to the liquid impermeable sheet 20a and the non-woven fabric 20b, and the leg-surrounding elastic member 52 is attached in a state of being stretched beyond its natural length. Moreover, it is preferable that the elastic member 52 for leg circumference is bonded to the liquid impermeable sheet 20a and the non-woven fabric 20b by the cured product 72 of the reactive urethane hot melt adhesive over the entire length.

The leg elastic members 52 may be intermittently cut below the absorbent core 32. This is because it is possible to prevent the crotch portion from being wrinkled by suppressing the application of contractile force to the crotch portion 2c.

It is also preferable that the waist elastic member 53 is provided between the waist elastic member 51 and the leg elastic member 52 in the front portion 2a and/or the rear portion 2b of the disposable diaper 1. The waist elastic member 53 is stretched from its natural length, and between the liquid-impermeable sheet 20a of the exterior sheet 20 and the nonwoven fabric 20b bonded to the outer surface of the liquid-impermeable sheet 20a, It is joined by a cured product 72a of a reactive urethane hot melt adhesive (FIG. 5). The contraction force of the waistline elastic member 53 improves the adhesion of the disposable diaper around the lower abdomen and the buttocks.

In the disposable diaper 1 of the preferred aspect 2, the absorbent core 32 is provided on the skin surface side of the exterior sheet 20 (see FIG. 6 ). The absorbent core 32 is preferably bonded to the skin side of the exterior sheet 20 with a non-reactive hot melt adhesive 55. The absorbent core 32 has the absorbent layer 30 between the liquid-permeable top sheet 10 and the liquid-impermeable back sheet 22. The liquid-impermeable back sheet 22 is wound up above the absorbent layer 30 and is joined to the outer surface side of both side edges of the top sheet 10 with a non-reactive hot melt adhesive 55. A pair of side sheets 40 are joined by a non-reactive hot melt adhesive 55 to the skin side of the widthwise both sides of the top sheet 10. The pair of side seats 40 constitutes a three-dimensional gather. The three-dimensional gathers are folded back inward in the width direction at the first folding edge 43, and then are folded back inward at the second folding edge 45 so as to cover the elastic member 41 for three-dimensional gathers. The elastic member 41 for three-dimensional gathers is joined to the side sheet 40 by a cured product 72a of a reactive urethane hot melt adhesive in a stretched state inside the second folded edge 45.

In this embodiment, it is preferable that the elastic member 41 for three-dimensional gathers is coated with a reactive urethane hot melt adhesive and attached to the side sheet 40. Further, it is also preferable that only both ends of the elastic member 41 for three-dimensional gathers are joined to the side sheet 40 by the cured product 72a of the reactive urethane hot melt adhesive.

The nonwoven fabric 20b of the exterior sheet 20 is longer in the vertical direction than the liquid-impermeable sheet 20a, and is folded back to the skin side at the vertical edge. Further, the end pressing sheet 12 is arranged in the front portion 2a and the rear portion 2b so as to cover both longitudinal end portions of the absorbent core 32 (FIG. 5).

The method for manufacturing an absorbent article of the present invention is characterized in that the elastic member and the sheet member are joined together by using a reactive urethane hot melt adhesive.

The reactive urethane hot melt adhesive may be applied to either the elastic member or the sheet member. When the elastic member is in the form of threads, it is preferable to apply the reactive urethane hot melt adhesive to the entire surface of the elastic thread to which the adhesive is applied.

The absorbent article produced by using the reactive urethane hot melt adhesive is preferably cured at a humidity of 40% RH to 70% RH and a temperature of 15°C to 35°C for 72 hours to 120 hours. The curing does not require any special treatment, and is preferably performed by storing it in a warehouse as a final product. By curing under the above conditions, the moisture curing reaction of the reactive urethane hot melt adhesive proceeds and is cured. As a result, a three-dimensional crosslinked structure is formed and adhesive strength is developed.

1: disposable diaper, 2: diaper body, 2a: front part, 2b: rear back part, 2c: crotch part, 10: topsheet, 20: backsheet, 30: absorbent core, 40: sidesheet, 41: sidesheet Elastic member, 51: waist elastic member, 52: leg elastic member, 55: hot melt adhesive, 60: fastening member, 61: fastening base material, 62: knob portion, 63: first fastening member, 70: Second fastening member, 72: Reactive urethane hot melt adhesive

Claims (8)

Having an elastic member and a sheet member,
The absorbent member is characterized in that the elastic member is joined to the sheet member by a cured product of a reactive urethane hot melt adhesive. The absorbent article according to claim 1, wherein the elastic member has a thread shape or a band shape. The absorbent article according to claim 1, wherein the material of the elastic member is polyurethane or natural rubber. The absorbent article according to any one of claims 1 to 3, wherein the elastic member is joined to the sheet member at an extension ratio of 1.1 to 5.0 times the natural length. The absorbent article according to any one of claims 1 to 4, wherein the absorbent article is a disposable diaper, and the elastic member is a waist elastic member. The disposable diaper according to any one of claims 1 to 5, wherein the absorbent article is a disposable diaper, and the elastic members are leg elastic members. The said absorbent article is a disposable diaper, The said elastic member is an elastic member for waist circumferences, The disposable diaper as described in any one of Claims 1-6. The said absorbent article is a disposable diaper, The said elastic member is an elastic member for three-dimensional gathers, The disposable diaper as described in any one of Claims 1-7.

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