JP2019165828A - Disposable diaper - Google Patents

Abstract

To provide a disposable diaper which does not lose shape during manufacturing and is capable of restraining fastening members from detaching from the diaper body even when the wearer uses a heating appliance, and also to provide a method of manufacturing such a disposable diaper.SOLUTION: A disposable diaper according to the present invention comprises: a diaper body having an absorbent core; left and right fastening members respectively joined to both side edges of a rear part of the diaper body, and outwardly extending in a width direction from the diaper body; first fixing members respectively provided on skin surface sides of the left and right fastening members; and second fixing members which are provided on an outer surface side of a front part of the diaper body, and to which the first fixing members are detachably fastened. The diaper body and the fastening members are joined to each other by a cured material of a reactive urethane hotmelt adhesive and a non-reactive hotmelt adhesive.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a disposable diaper, and more particularly to a disposable diaper having a fastening means.

  A disposable diaper having a fastening means has been proposed. In a disposable diaper having such fastening means, a load is easily applied to the joint portion between the fastening base material and the diaper body constituting the fastening means, and the joint portion may be peeled off or damaged. Therefore, it is important to ensure the strength of the joint between the fastening base material and the diaper body.

  As a disposable diaper having such fastening means, a diaper having improved joint strength of the joint has been proposed. For example, in Patent Document 1, a fastening base material joint has a plurality of adhesive application regions, and the adhesive applied to the plurality of adhesive application regions includes a rubber adhesive and an olefin adhesive. A disposable diaper has been proposed (see Patent Document 1 (claim 2, paragraph 0006)).

  In addition, when a surface fastener is used as the fastening means, it has also been proposed to improve the joint strength of the joint portion between the fastening base material and the surface fastener. For example, Patent Document 2 discloses a polyurethane prepolymer obtained by polyaddition of at least one polyol to at least one diisocyanate trimerized as isocyanurate, a reaction product of diisocyanate and water, Hygiene having a fixing element in the form of a woven mesh bonded by a moisture-crosslinkable hot melt adhesive comprising a pre-polymer free NCO group content of 1 to 25% by weight Articles have been proposed (see Patent Document 2 (claim 12, paragraphs 0004 and 0005)).

JP 2011-097975 A JP-T-2001-527117

  When the wearer of the disposable diaper uses a heater (electric blanket, kotatsu, etc.), the joint between the fastening member and the diaper body is warmed. Therefore, the hot melt adhesive used for joining the fastening member and the diaper body may be softened and the fastening member may be detached from the diaper body. Disposable diapers are manufactured at a high speed of about 150 to 250 per minute, and the shearing force received from rolls and guides on the production line is large. When a reactive hot melt adhesive as described in Patent Document 2 is used, the initial adhesive strength is insufficient, and the disposable diaper may lose its shape when the disposable diaper is manufactured at high speed. .

  The present invention has been made in view of the above circumstances, and there is no loss of shape of the disposable diaper at the time of manufacture. Further, even when the wearer uses a heating appliance, the detachment of the fastening member from the diaper main body is suppressed. It is an object of the present invention to provide a disposable diaper (having a high heat-resistant adhesive strength between a fastening member and a diaper main body) and a method for manufacturing the disposable diaper.

  The disposable diaper of the present invention includes a diaper main body having an absorbent core, left and right fastening members respectively joined to both side edges of a rear portion of the diaper main body, and extending outward in the width direction from the diaper main body, and the left and right fastenings. A first fastening member provided on the skin surface side of the member; a second fastening member provided on the outer surface side of the front portion of the diaper main body, wherein the first fastening member is detachably fastened; The diaper main body and the fastening member are joined by a cured product of a reactive urethane hot melt adhesive and a non-reactive hot melt adhesive.

  In the disposable diaper of the present invention, the diaper main body and the fastening member are joined by a cured product of a reactive urethane hot melt adhesive and a non-reactive hot melt adhesive. The reactive urethane hot melt adhesive used in the present invention is cured by forming a three-dimensional crosslink by reacting with moisture in the air. That is, the cured product of the reactive urethane hot melt adhesive is not plasticized by heating. Therefore, even when the wearer uses a heater, the cured product of the reactive urethane hot melt adhesive that joins the diaper body and the fastening member does not soften, and the fastening member can be detached from the diaper body. It is suppressed. The non-reactive hot melt adhesive used in the present invention solidifies at room temperature and develops adhesive strength. Since the diaper main body and the fastening member are fixed by the non-reactive hot melt adhesive, the adhesive strength between the diaper main body and the fastening member at the time of manufacture is good.

  ADVANTAGE OF THE INVENTION According to this invention, the disposable diaper by which the detachment | leave from the diaper main body of a fastening member was suppressed is obtained, even when a wearer uses a heating appliance without the shape loss at the time of manufacture.

The top view which looked at an example of the disposable diaper of this invention from the top sheet side. The top view which looked at the disposable diaper of FIG. 1 from the back seat | sheet side. The typical sectional view of the VV line of Drawing 1. The perspective view which shows the state with which the disposable diaper of FIG. 1 was worn. Explanatory drawing which illustrates the joining state of a fastening member and a diaper main body. Explanatory drawing which illustrates the joining state of a fastening member and a diaper main body. Explanatory drawing regarding the production process of a fastening member. Explanatory drawing which illustrates the process of apply | coating a hot-melt-adhesive agent to a fastening base material continuous body. The side view of a coater head. Sectional drawing along the A2-A2 line of FIG. FIG. 10 is an exploded perspective view of the coater head of FIG. 9. Explanatory drawing explaining the adhesive force test method of a fastening member.

  The disposable diaper of the present invention includes a diaper main body having an absorbent core, left and right fastening members respectively joined to both side edges of a rear portion of the diaper main body, and extending outward in the width direction from the diaper main body, and the left and right fastenings. A first fastening member provided on the skin surface side of the member; a second fastening member provided on the outer surface side of the front portion of the diaper main body, wherein the first fastening member is detachably fastened; The diaper main body and the fastening member are joined by a cured product of a reactive urethane hot melt adhesive and a non-reactive hot melt adhesive.

  The reactive urethane hot melt adhesive is a moisture curable adhesive, and reacts with moisture in the air to form a three-dimensional crosslink and cure. That is, the cured product of the reactive urethane hot melt adhesive is not softened by heating, and has excellent heat resistance. Therefore, the disposable diaper of the present invention can suppress detachment of the fastening member from the diaper body even when the wearer uses the heater and the joint between the diaper body and the fastening member is warmed. In addition, the reactive urethane hot melt adhesive can be applied in a molten state as in the conventional hot melt, and can be temporarily joined to the adherend by cooling and solidifying. Therefore, if a reactive urethane hot melt adhesive is used, conventional manufacturing equipment can be used, and a decrease in productivity can be suppressed.

(Reactive urethane hot melt adhesive)
First, the reactive urethane hot melt adhesive used for joining of a fastening member is demonstrated. The reactive urethane hot melt adhesive is moisture curable. The reactive urethane hot melt adhesive contains a urethane prepolymer having an isocyanate group at the end of the molecular chain.

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

  Although it does not specifically limit as said polyol, For example, polyether polyol, polyester polyol, polycarbonate polyol, polycaprolactone etc. are mentioned. Moreover, triols, such as a trimethylol propane, can be mentioned.

  The polyisocyanate is a compound having at least two isocyanate groups in the molecule. Examples of the polyisocyanate include yellowing 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. Mention may be made of yellowed diisocyanates. In the present invention, it is preferable to use diisocyanate as the polyisocyanate.

  The content of isocyanate groups in the reactive urethane hot melt adhesive used in the present invention is preferably 1% by mass or more, more preferably 3% by mass or more, still more preferably 5% by mass or more, and 25% by mass or less. More preferably, it is 23 mass% or less, More preferably, it is 21 mass% or less. If the isocyanate group content is 1% by mass or more, the curing rate is high, and if it is 25% by mass or less, the adhesive strength is excellent.

(Non-reactive hot melt adhesive)
Next, the non-reactive hot melt adhesive used in the present invention will be described. 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 an adhesive force by solidifying at an ordinary temperature. Examples of non-reactive hot melt adhesives include rubber hot melt adhesives, olefin hot melt adhesives, polyamide hot melt adhesives, and polyester hot melt adhesives.

  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 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, synthetic rubbers include 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 preferable. The styrene block copolymer may have a linear molecular structure or a radial molecular structure.

  The olefin hot melt adhesive preferably contains an olefin polymer. Examples of the olefin polymer include polyolefin, polyolefin copolymer, and olefin / α-olefin interpolymer. Examples of the olefin-based polymer include amorphous, semi-crystalline, and crystalline ones. For example, amorphous (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 (eg, cycloparaffinic oils), mineral oils, phthalic acid esters, adipic acid esters, olefin oligomers (eg, polypropylene, polybutene and hydrogenated polyisoprene oligomers). ), Polybutene, polyisoprene, hydrogenated polyisoprene, polybutadiene, benzoic acid esters, animal oils, vegetable oils (eg, castor oil, soybean oil), oil derivatives, glycerol esters of fatty acids, polyesters, polyethers, 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 functional groups such as hydroxy stearamide wax and fatty amide wax. Examples thereof include a basic wax.

    The reactive urethane hot melt adhesive and the non-reactive hot melt adhesive may further include additives such as a stabilizer, an antioxidant, a pigment, a dye, and an ultraviolet absorber.

(Disposable diapers)
Next, the structure of the disposable diaper of this invention is demonstrated. The disposable diaper is joined to the diaper main body, both side edges of the rear part of the diaper main body, and left and right fastening members extending outward in the width direction from the diaper main body, and on the skin surface side of the left and right fastening members A first fastening member provided on each side, and a second fastening member provided on the outer surface side of the front portion of the diaper main body and detachably fastened to the first fastening member.

  The diaper body has an absorbent core that absorbs liquid and is applied to the wearer. The diaper main body has a front part, a crotch part, and a rear part. The front part is applied to the wearer's belly side, the rear part is applied to the wearer's back side, and the crotch part is applied to the inseam of the wearer. In addition, in the said diaper main body and a fastening member, the side facing a wearer's skin at the time of wear is a skin surface side, and the back surface of this skin side is an outer surface side.

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

  The diaper main body preferably includes a top sheet disposed on the skin surface side of the absorbent core and a back sheet disposed on the outer surface side of the absorbent core.

  The said top sheet has liquid permeability, and permeate | transmits the excretion liquid from a wearer rapidly. Examples of the top sheet include a nonwoven fabric formed of hydrophilic fibers. Examples of the hydrophilic fiber include cellulose, rayon, and cotton. Examples of the nonwoven fabric include point bond nonwoven fabric, air-through nonwoven fabric, spunlace nonwoven fabric, spunbond nonwoven fabric, and airlaid nonwoven fabric. The shape of the top sheet is not particularly limited, and examples thereof include a rectangular shape, an hourglass shape, a gourd shape, and a battledore shape, and a rectangular shape is preferable.

  The back sheet may be either a liquid permeable sheet or a liquid impermeable sheet, but is preferably a liquid impermeable sheet. If it is a liquid-impervious sheet, it can prevent that the excretion liquid which reached | attained the back sheet oozes out to the outer surface side of a diaper main body. As the liquid-impervious sheet, a water-repellent or liquid-impervious nonwoven fabric (for example, spunbond nonwoven fabric, melt blown nonwoven fabric, SMS (spunbond) formed of hydrophobic fibers (for example, polypropylene, polyethylene, polyester, polyamide). • Melt blow / spun bond) non-woven fabric) and water-repellent or liquid-impervious plastic films can be used. The shape of the back sheet is not particularly limited, and examples thereof include a rectangular shape, an hourglass shape, a gourd shape, and a battledore shape, and are preferably an hourglass shape or a gourd shape.

  Moreover, you may use the laminated sheet comprised from the liquid impervious sheet and the nonwoven fabric bonded together on the outer surface side of this liquid impervious sheet as the said back sheet. When the back sheet is a laminated sheet made of a liquid-impervious sheet and a nonwoven fabric bonded to the outside of the liquid-impervious sheet, the liquid-impervious sheet is arranged on both side edges of the rear part of the back sheet. However, it is preferably composed of only a nonwoven fabric.

The basis weight of the nonwoven fabric used for the backsheet is preferably 10 g / m ² or more, more preferably 12 g / m ² or more, further preferably 13 g / m ² or more, preferably 25 g / m ² or less, and 21 g / m ² or less. More preferred is 18 g / m ² or less.

  As the non-woven fabric used for the backsheet, it is preferable to use a non-woven fabric obtained by the SMMS (spun bond / melt blow / melt blow / spun bond) method made of polypropylene (resin).

  The diaper main body may have left and right side sheets on the skin surface side. The left and right side sheets are preferably joined to both side edges of the top sheet on the skin surface side along the longitudinal direction (front-rear direction) with an interval in the width direction on the skin surface side of the top sheet. The side sheet on the inner side in the width direction from the joining point of the side sheet and the top sheet is not joined to the top sheet, and is a free end. An elastic member extending in the front-rear direction is disposed at the inner ends of the left and right side seats (upper end when standing). The inner front ends of the left and right side sheets are configured to be able to stand up in the direction away from the top sheet (skin surface side) by the contraction force of the elastic member. A solid gather is constituted by the side seats and the elastic members, and side leakage of urine and feces excreted by the solid gather is prevented. Examples of the side sheet include a water-repellent or liquid-impervious nonwoven fabric (for example, spunbond nonwoven fabric, meltblown nonwoven fabric, SMMS (spunbond / meltblown) formed of hydrophobic fibers (for example, polypropylene, polyethylene, polyester, polyamide). It is preferable to use (melt blown / spunbond) non-woven fabric).

  The shape of the side sheet is not particularly limited, but preferably has a shape that covers both sides of the back sheet. For example, the side sheet preferably has a shape obtained by dividing an hourglass-type sheet into two in the vertical direction. .

Basis weight of the nonwoven fabric used for the side sheet, 12 g / m ² or more preferably, 14 g / m ² or more preferably, 15 g / m ² or more, and preferably 25 g / m ² or less, 21g / m ² or less More preferred is 18 g / m ² or less.

  As the nonwoven fabric used for the side sheet, it is preferable to use a nonwoven fabric obtained by a polypropylene (resin) SMMS (spunbond / meltblown / meltblown / spunbond) method.

  The diaper main body is provided with a second fastening member on the outer surface side of the front portion. This second fastening member can be detachably fastened with a first fastening member of a fastening member described later. What is necessary is just to adjust suitably the position and range which provide the said 2nd fastening member according to the shape of the fastening member mentioned later, and the position of the 1st fastening member.

  The disposable diaper of this invention has a fastening member. The left and right fastening members are joined to both side edges of the rear portion of the diaper body, and are formed to extend outward in the width direction from the diaper body. The said fastening member has a fastening base material and the 1st fastening member provided in the skin surface side of the fastening base material. The fastening base material has a fixed end portion joined to the diaper main body and a tip end portion provided with the first fastening member. Fastening means is constituted by the pair of left and right fastening members provided with the first fastening member and the second fastening member provided on the diaper main body. When the disposable diaper is worn, the fastening means is used to fasten the front part and the rear part of the diaper main body to form a waistline.

A fastening base material can be suitably selected from a nonwoven fabric, a woven fabric, a knitted fabric, and a resin film material, for example. As the fastening substrate, a nonwoven fabric produced by a combination of one or a plurality of production methods among a spun bond 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 SMMS method combining the spunbond method and the 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. Preferably, synthetic fibers such as polypropylene, polyethylene and polyester can be used. As the fastening base material, a material mainly composed of polypropylene or polyester fiber has strength and is suitable. The most preferable material for the fastening substrate is polypropylene 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 hook-and-loop fastener; the first fastening member is an adhesive tape, A mode in which the second fastening member is an adhesive sheet to which the adhesive tape can be detachably attached is exemplified. In addition, when employ | adopting a hook_and_loop | surface fastener, it is preferable to arrange | position a hook material to a 1st fastening member and to arrange | position a loop material to a 2nd 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. As the shape of the hook of the hook material, a hook shape, a piece shape, a mushroom shape, or the like is preferable. Examples of the hook material include “Magic Tape (registered trademark)” (manufactured by Kuraray Co., Ltd.), “Quicklon (registered trademark)” (manufactured by YKK), “Majikuros (registered trademark)” (manufactured by Kanebo Bell Touch), and the like. Commercial products can be used. As the second fastening member, for example, a loop material (nonwoven fabric, woven fabric, knitted fabric, etc., a resin film composite material having a nonwoven fabric, woven fabric, etc. on the surface) in which a fine loop structure is densely provided in a planar shape is used. Used.

  In the disposable diaper of the present invention, the diaper main body and the fastening member are joined by a cured product of a reactive urethane hot melt adhesive and a non-reactive hot melt adhesive. At least one of the skin surface side and the outer surface side of the fixed end portion of the fastening member may be joined to the diaper main body by a cured product of a reactive urethane hot melt adhesive and a non-reactive hot melt adhesive. preferable. For example, one of the skin surface side and the outer surface side of the fixed end portion of the fastening member is joined to the diaper main body by a cured product of a reactive urethane hot melt adhesive and a non-reactive hot melt adhesive, and the other is It is preferable that the diaper main body is joined only by the non-reactive hot melt adhesive.

  In the present invention, as an aspect of joining the diaper main body and the fastening member, for example, joining the outer surface side joint surface of the both side edges of the rear part of the diaper main body and the skin surface side joint surface of the fixing end of the fastening member. An aspect of joining the skin surface side joining surface of both side edges of the rear part of the diaper main body and the outer surface side joining surface of the fixing end of the fastening member, and a member constituting the diaper main body (for example, a top sheet) , A side sheet, or a back sheet), and the fastening end portion of the fastening member is sandwiched and joined.

  As a mode of sandwiching and joining the fixed end of the fastening member with the members constituting the diaper main body, for example, the top end and the back sheet constituting both side edges of the diaper main body are sandwiched between the fixed end of the fastening member. A mode of joining, a side sheet that constitutes both side edges of the diaper main body rear part, a mode of sandwiching and fixing the fastening end portion of the fastening member with the back sheet, a top sheet that constitutes both side edges of the rear part of the diaper main body, and The aspect which pinches | interposes the fixing end part of a fastening member with a side sheet | seat, and can join can be mentioned.

In a region where the fastening member and the diaper main body are joined (hereinafter, sometimes simply referred to as “joint portion”), the application amount per one application surface of the cured product of the reactive urethane hot melt adhesive is 5 g. / ^{m 2} or more, more preferably 10 g / ^{m 2} or more, more preferably 15 g / ^{m 2} or more, preferably 100 g / ^{m 2} or less, more preferably 80 g / ^{m 2,} more preferably 50 g / ^{m 2} or less .

In the region where the fastening member and the diaper main body are joined (joined part), the application amount per one application surface of the non-reactive hot melt adhesive is preferably 10 g / m ² or more, and 20 g / m ^2. The above is more preferable, 35 g / m ² or more is more preferable, 70 g / m ² or less is preferable, 60 g / m ² or less is more preferable, and 50 g / m ² or less is more preferable.

  The mass ratio (Reactive PUHM / Non-Reactive HM) of the application amount per application surface of the cured product of the reactive urethane hot melt adhesive and the non-reactive hot melt adhesive at the joint between the fastening member and the diaper main body. ) Is preferably 5/70 to 100/10, more preferably 10/60 to 80/20, and even more preferably 15/50 to 50/35.

  The peeling time in the 40 ° C. environment of the joint between the fastening member and the member of the diaper main body to be joined to the fastening member is preferably 500 minutes or more, more preferably 750 minutes or more, and even more preferably 1000 minutes or more. is there. This is because, if the peeling time is 500 minutes or more, even when the wearer uses the heater and the joint between the diaper main body and the fastening member is warmed, detachment of the fastening member from the diaper main body can be suppressed. In addition, the measuring method of peeling time is mentioned later.

  The bonding strength of the joint between the member constituting the diaper body and the fastening member is preferably 10 N / 50 mm or more, more preferably 11 N / 50 mm or more, further preferably 12 N / 50 mm or more, preferably 20 N / 50 mm or less, 19 N / 50 mm. The following is more preferable, and 18 N / 50 mm or less is further preferable. This is because if the adhesive strength is within the above range, the detachment of the fastening member can be suppressed. In addition, the said adhesive strength is an adhesive strength when 18 hours or more pass at 15 degreeC-35 degreeC and humidity 40%-70% after apply | coating a hot-melt-adhesive.

  Hereinafter, although the disposable diaper of this invention is demonstrated, referring drawings, this invention is not limited to the aspect shown by drawing.

  Drawing 1 is a top view which looked at disposable diaper 1 concerning one embodiment of the present invention from the top sheet 10 side in the state where it developed. FIG. 2 is a plan view of the disposable diaper 1 as viewed from the backsheet 20 side in the unfolded state. FIG. 3 is a cross-sectional view of the disposable diaper 1 taken along line VV in FIG. FIG. 4 is a perspective view showing a state in which the disposable diaper of FIG. 1 is worn. 1 and 2 show a state where a side seat 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, the arrow A is defined as the front-rear direction and the arrow B is defined as the width direction. The direction on the surface formed by the arrows A and B is defined as the plane direction. The vertical direction with respect to the surface formed by the arrows A and B represents the up-down direction C.

  As shown in FIGS. 1 to 3, the disposable diaper 1 includes a liquid-permeable top sheet 10, a liquid-impermeable back sheet 20, and an absorbent core 30 interposed between both sheets 10 and 20. The diaper main body 2 which is a laminated body is provided.

  The diaper main body 2 has a front part 2a applied to the wearer's abdomen, a rear part 2b applied to the back of the wearer, and a crotch part 2c connecting the front part 2a and the rear part 2b. Hereinafter, the direction in which the front abdominal part 2a, the crotch part 2c, and the back part 2b are connected is referred to as “front-rear direction”, and the direction perpendicular to the front-rear direction and along the surface of the diaper body 2 is referred to as “width direction”. The diaper main body 2 extends in the front-rear direction from the front part 2a to the rear part 2b, and is constricted in the width direction at the crotch part 2c located in the middle.

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

  The back sheet 20 is a liquid-impermeable sheet disposed on the outer surface side of the diaper main body 2. The backsheet 20 has substantially the same shape as the diaper body 2 in plan view. That is, the back sheet 20 covers the entire lower surface of the diaper body 2.

  The absorbent core 30 is fixed between the top sheet 10 and the back sheet 20 and has liquid absorption and liquid retention. As shown in FIG. 3, the absorbent core 30 is fixed between the top sheet 10 and the back sheet 20 by a hot melt adhesive 55. Moreover, as shown in FIG. 1, the absorption core 30 is formed slightly smaller than the outer edge of the diaper main body 2 in plan view.

  A second fastening member 70 is provided on the outer surface side of the front portion 2 a of the backsheet 20. In FIG. 2, the shape of the second fastening member 70 is rectangular, but is not limited to this shape.

  On the upper surface side of the top sheet 10, a pair of side sheets 40 for preventing urine leakage to the side is provided. The pair of side sheets 40 extends in the front-rear direction so as to cover the left and right side edges of the diaper body 2. As shown in FIG. 3, the pair of side sheets 40 are joined to the absorbent core via a hot melt adhesive 55 on the outer side in the width direction of the top sheet. Moreover, a pair of side sheet | seat 40 is joined to the skin surface side of a fastening member in the width direction outer side of an absorption core. The fastening member and the diaper main body are formed by a reactive urethane hot-melt adhesive and a non-reactive hot-melt adhesive at the joint 80 between the fastening member and the side sheet and / or the joint 81 between the fastening member and the backsheet. It is joined. The side edge portion on the inner side in the width direction of the side sheet 40 is not attached to the upper surface of the top sheet 10 and can rise with respect to the top sheet 10.

  A plurality of side seat elastic members 41 extending in the front-rear direction are disposed on the side edge portion of the side seat 40 in the width direction. The side sheet elastic member 41 is attached to the side sheet 40 with an adhesive (not shown) in a state of being extended beyond the natural length. For this reason, the elastic member 41 for side sheets generates the elastic force which shrinks the side sheet 40 to a longitudinal direction.

  When the disposable diaper is opened, the side edge of the side seat 40 on the inner side in the width direction rises due to the elastic force of the side seat elastic member 41. Thereby, a pair of upstanding weirs are formed on the upper surface of the diaper main body 2, and leakage of urine excreted by the wearer to the side is prevented.

  A plurality of waist elastic members 51 extending in the width direction are provided on the front portion 2a and the rear portion 2b. The waist elastic member 51 is attached between the top sheet 10 and the back sheet 20 with an adhesive (not shown) in a state where the elastic member 51 is stretched beyond the natural length. Therefore, the waist elastic member 51 generates an elastic 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 part 2 a and the rear part 2 b can be fitted around the waist of the wearer by the contraction force of the waist elastic member 51.

  Further, a plurality of leg-around elastic members 52 extending in the front-rear direction are provided on both side edges in the width direction of the crotch portion 2c. The leg-around elastic member 52 is attached between the side sheet 40 and the back sheet 20 with an adhesive (not shown) in a state where the elastic member 52 is extended beyond the natural length. For this reason, the leg-hole elastic member 52 generates an elastic force that contracts both side edges of the crotch 2c in the longitudinal direction. When the wearer wears the disposable diaper 1, both side edges of the crotch 2 c can be fitted to the wearer's thigh by the contraction force of the leg-around elastic member 52.

  For the side seat elastic member 41, the waist elastic member 51, and the leg elastic member 52, for example, thread-like elastic members such as polyurethane yarns may be used. Further, instead of the thread-like elastic member, a flat elastic member made of polyurethane, natural rubber or the like may be used.

  The disposable diaper 1 includes a pair of fastening members 60. Each fastening member 60 includes a fastening base 61 and two tongue-shaped tabs 62 projecting outward in the width direction from the end of the fastening base 61 on the free end side. A first fastening member 63 is provided on the skin side surface of each knob portion 62. The fastening base 61 is sandwiched between the side sheet 40 and the back sheet 20 at the fixed end 61a on the inner side in the width direction and joined to the diaper main body. A hook material (male member) of a hook-and-loop fastener is used for the first fastening member 63 of the present embodiment. On the other hand, as shown in FIG. 2, the 2nd fastening member 70 which attaches the 1st fastening member 63 so that attachment or detachment is possible is provided in the outer surface of the front part 2a of the diaper main body 2. As shown in FIG. A loop material (female member) of a hook-and-loop fastener is used for the second fastening member 70 of the present embodiment.

  In the disposable diaper 1, the fastening member 60 and / or the joint 81 between the fastening member 60 and the diaper main body 2 are bonded via a cured product of a reactive urethane hot melt adhesive and a non-reactive hot melt adhesive. 60 is joined to the diaper main body 2.

  Each fastening member 60 is joined to a portion of the rear portion 2b of the diaper main body 2 that protrudes outward in the width direction from the crotch portion 2c. Specifically, as shown in FIG. 3, the fixed end 61 a of the fastening substrate 61 is joined to the side sheet 40 and the back sheet 20 with a reactive urethane hot melt adhesive and a non-reactive hot melt adhesive. ing. In the aspect shown in FIG. 3, since the width of the top sheet 10 is shorter than the width of the back sheet 20, there is no top sheet on both side edges in the back sheet width direction, and the side sheets 40 are provided. Yes. Therefore, the fixed end portion 61 a of the fastening base material 61 is sandwiched and joined between the side sheet 40 and the back sheet 20.

  The back sheet 20 is a laminated sheet composed of a liquid-impervious sheet 20a and a nonwoven fabric 20b bonded to the outside of the liquid-impervious sheet 20a. In the rear part 2b of the backsheet 20, the width of the liquid-impervious sheet 20a is narrower than the width of the nonwoven fabric 20b, and the liquid-impervious sheet 20a is arranged on both side edges of the rear part 2b of the backsheet 20. It is not, and is comprised from the nonwoven fabric 20b. When the side sheet 40 is made of a nonwoven fabric, both sides of the rear part of the diaper body have a structure in which two nonwoven fabrics of a side sheet and a back sheet are laminated.

  As an application mode of the reactive urethane hot melt adhesive and the non-reactive hot melt adhesive, the reactive urethane hot melt is bonded at the joint 80 and / or the joint 81 where the diaper body 2 and the fastening member 60 are joined. Examples include an aspect in which the adhesive and the non-reactive hot melt adhesive are applied in a stripe shape, an aspect in which the adhesive is applied in an omega form, an aspect in which the adhesive is applied in a spiral form, and an aspect in which the adhesive is applied in a curtain form. Among these, it is preferable to apply the non-reactive hot melt adhesive in a stripe shape and the reactive urethane hot melt adhesive in a spiral shape or an omega shape.

  In FIG. 5A, for example, at the joint 80 and / or the joint 81 where the diaper body 2 and the fastening member 60 are joined, the reactive urethane hot melt adhesive 72 and the non-reactive hot melt adhesive 55 Are respectively applied in stripes. FIG. 5B shows a mode in which the non-reactive hot melt adhesive 55 is applied in a stripe shape and the reactive urethane hot melt adhesive 72 is applied in a spiral shape. By applying the contact coating method and the non-contact coating method in combination, two types of hot melt adhesives can be applied with high accuracy.

  Furthermore, specific examples of the application mode of the reactive urethane hot melt adhesive 72 and the non-reactive hot melt adhesive 55 include the modes (a) to (b) of FIG. In the embodiment of FIG. 6A, a reactive urethane hot melt adhesive 72 is formed by the skin surface side bonding surface of the fixed end 61 a of the fastening base material 61 and the outer surface side bonding surface of the side sheet 40 constituting the diaper main body. And a non-reactive hot melt adhesive 55. Similarly, the outer surface side bonding surface of the fixed end portion 61a of the fastening base material 61 and the skin surface side bonding surface of the back sheet 20 are bonded to the cured product of the reactive urethane hot melt adhesive 72 and non-reactive hot melt bonding. Bonded by the agent 55. The cured product of the reactive urethane hot melt adhesive 72 is preferably applied on the outer side in the width direction of the fixed end portion of the fastening base material 61a, and the non-reactive hot melt adhesive 55 is preferably applied on the inner side in the width direction. Moreover, it is preferable that the non-reactive hot melt adhesive applied to the inner side in the width direction is applied in a stripe shape. The reactive urethane hot melt adhesive applied to the outside is preferably applied in a spiral or omega form.

  In the present invention, at least one of the skin surface side and the outer surface side of the fastening member fixed end portion is formed of a diaper body, a cured product of a reactive urethane hot melt adhesive, and a non-reactive hot melt adhesive. What is necessary is just to join. In the embodiment shown in FIG. 6 (a), each of the diaper main body, the skin-side joining surface and the outer-side joining surface of the fixed end portion of the fastening member is a cured product of a reactive urethane hot melt adhesive, Bonded with a reactive hot melt adhesive.

  In the embodiment of FIG. 6 (b), the skin surface side joint surface of the fixed end portion 61a of the fastening base material 61 and the outer surface side joint surface of the side sheet 40 constituting the diaper body 2 are reactive urethane hot melt adhesives. The cured product 72 and the non-reactive hot melt adhesive 55 are joined together. The cured product of the reactive urethane hot melt adhesive 72 is preferably applied on the outer side in the width direction of the fastening base material fixing end 61a, and the non-reactive hot melt adhesive 55 is preferably applied on the inner side in the width direction. The non-reactive hot melt adhesive 55 applied on the inner side in the width direction is preferably applied in a stripe shape. The reactive urethane hot melt adhesive 72 applied to the outside is preferably applied in a spiral or omega shape. Further, the outer surface side bonding surface of the fixing end 61 a of the fastening base material 61 and the skin surface side bonding surface of the back sheet 20 are fixed only by the non-reactive hot melt adhesive 55.

  In the embodiment shown in FIG. 6 (b), the diaper main body and the skin-side joining surface of the fixed end portion of the fastening member are a cured product of a reactive urethane hot melt adhesive, a non-reactive hot melt adhesive, It is joined by. The diaper main body and the outer side joining surface of the fastening end portion of the fastening member are fixed only by the non-reactive hot melt adhesive. Such an aspect is also included in the present invention.

  The embodiment shown in FIG. 6C is not included in the present invention. In the aspect of FIG. 6C, the skin surface side joint surface of the fixed end 61 a of the fastening base 61 and the outer surface side joint surface of the side sheet 40 constituting the diaper main body are the reactive urethane hot melt adhesive 72. It is fixed only by the cured product, and the outer surface side bonding surface of the fixed end portion 61 a of the fastening substrate 61 and the skin surface side bonding surface of the back sheet 20 are fixed only by the non-reactive hot melt adhesive 55. Similarly, contrary to the mode of FIG. 6C, the skin side joining surface of the fixed end portion 61 a of the fastening base material 61 and the outer side joining surface of the side sheet 40 constituting the diaper main body 2 are non-reactive. A cured product of the reactive urethane hot melt adhesive 72, which is fixed only by the reactive hot melt adhesive 55, and the outer surface side bonding surface of the fixed end portion 61 a of the fastening substrate 61 and the skin surface side bonding surface of the backsheet 20. The aspect fixed only by this is not included in the present invention. In the embodiment of FIG. 6 (c), the cured product of the reactive urethane hot melt adhesive and the non-reactive hot melt are bonded to the diaper main body and the joint portion on the skin surface side and the outer surface side of the fastening end portion of the fastening member. Not joined by both adhesives.

  The application mode of the reactive urethane hot melt adhesive and the non-reactive hot melt adhesive is not limited to the mode illustrated in FIGS. 6A to 6B, and the configuration of the diaper main body and the fastening of the fastening member Modifications can be made as appropriate based on the matching mode.

  When the disposable diaper 1 is worn, first, the disposable diaper 1 is applied to the wearer so that the front part 2a, the crotch part 2c, and the rear part 2b face the wearer's abdomen, crotch, and back, respectively. Next, both fastening members 60 are pulled to the abdominal surface side along the wearer's side waist, and the first fastening member 63 is attached to the second fastening member 70. Thereby, as shown in FIG. 4, the front part 2a and the rear part 2b of the diaper main body 2 are fastened, and a waistline is formed.

  The disposable diaper manufacturing method of the present invention includes a diaper body having an absorbent core, left and right fastening members respectively joined to both side edges of a rear portion of the diaper body, and extending outward in the width direction from the diaper body; A first fastening member provided on the skin surface side of each of the left and right fastening members, and a second stop provided on the outer surface side of the front portion of the diaper main body, wherein the first fastening member is detachably fastened. A disposable diaper manufacturing method having a wearing member, wherein both side edges in the width direction and a fastening member in the rear part of the diaper main body are made of a reactive urethane hot melt adhesive and a non-reactive hot melt adhesive. It is characterized by using and joining.

  The reactive urethane hot melt adhesive and the non-reactive hot melt adhesive are used for the diaper main body and the fastening member as long as the both side edges in the width direction in the rear side portion of the diaper main body can be joined to the fastening member. What is necessary is just to determine suitably based on the structure of a diaper main body, the joining aspect of a fastening member and a diaper main body, etc.

  For example, the outer surface side of the side sheet constituting the diaper main body and the skin surface side of the fastening member are joined with the cured product of the reactive urethane hot melt adhesive and the non-reactive hot melt adhesive to form the diaper main body. The method for producing a disposable diaper in which the skin surface side of the sheet and the outer surface side of the fastening member are fixed with a non-reactive hot melt adhesive preferably includes the following steps.

  A) A step of applying a non-reactive hot melt adhesive 55 to the skin side of the back sheet. The absorbent core 30 is joined to the back sheet 20 by the non-reactive hot melt adhesive 55. The non-reactive hot melt adhesive 55 applied to both side edges in the width direction of the back sheet 20 where the absorbent core 30 is not disposed has a skin surface side of the back sheet 20 and an outer surface side of the fastening member 60, and It is used to join the skin surface side of the back sheet 20 and the outer surface side of the side sheet 40. The non-reactive hot melt adhesive 55 is preferably applied by a contact type or non-contact type application device. Moreover, it can apply | coat to stripe form or spiral form.

  B) A step of laminating the absorbent core 30 on the backsheet 20 to which the non-reactive hot melt adhesive 55 is applied. At the time of lamination, it is preferable to position the back sheet 20 so that the center line in the width direction and the center line in the width direction of the absorbent core 30 substantially coincide.

C) A step of laminating the top sheet 10 and the side sheet 40.
The side sheet 40 is joined to the width direction both ends of the skin surface side of the top sheet 10 by the adhesive applied to the width direction both ends of the skin surface side of the top sheet 10 or the side sheet 40 or by heat welding. The laminated body which joined the side sheet 40 to the width direction both ends by the side of the skin surface of the top sheet 10 is produced. Note that the side sheet 40 and the top sheet 10 may be sequentially stacked on the back sheet 20 on which the absorbent core is disposed without previously stacking the top sheet 10 and the side sheet 40.

  Moreover, it is preferable to apply the non-reactive hot melt adhesive 55 at both longitudinal ends of the width direction inner side region of the side sheet 40. The width direction inner side part of the side sheet 40 is joined to the top sheet 10 by the non-reactive hot melt adhesive 55 at both longitudinal ends. It is preferable that the non-reactive hot melt adhesive 55 is not applied to the portion corresponding to the upright portion of the width direction inner side region of the side sheet 40. The non-reactive hot melt adhesive 55 is preferably applied by a contact type or non-contact type application device. The non-reactive hot melt adhesive 55 is preferably applied in a stripe shape or a spiral shape.

  D) A step of applying the reactive urethane hot melt adhesive 72 and the non-reactive hot melt adhesive 55 to the skin surface side of the fastening member 60 (the fixed end portion 61a of the fastening substrate 61). The hot melt adhesive is preferably applied by a contact type or non-contact type application apparatus. The non-reactive hot melt adhesive is preferably applied in a stripe shape by a contact type application device. The reactive urethane hot melt adhesive is preferably applied in a curtain shape, an omega shape, or a spiral shape, more preferably in a spiral shape or an omega shape, with a non-contact type application device.

  E) A step of laminating the fastening member 60 on the laminate of the top sheet 10 and the side sheet 40. By the reactive urethane hot melt adhesive 72 and the non-reactive hot melt adhesive 55 applied to the skin surface side of the fastening member 60, the skin surface side joining of the fastening member 60 to both ends in the width direction on the outer surface side of the side sheet 40. The laminated body (laminated body of the top sheet 10, the side sheet 40, and the fastening member 60) which joined the surface and joined the fastening member 60 to the width direction both ends of the outer surface side of the side sheet 40 is produced.

  F) A step of applying a non-reactive hot melt adhesive 55 to the outer surface side of the laminate of the top sheet 10, the side sheet 40, and the fastening member 60. The non-reactive hot melt adhesive 55 joins the top sheet 10 and the side sheet 40 to the absorbent core 30 and the back sheet 20. The non-reactive hot melt adhesive 55 is preferably applied by a contact type or non-contact type application device. The non-reactive hot melt adhesive 55 is preferably applied in a stripe shape or a spiral shape.

  E) A step of laminating the laminate of the top sheet 20, the side sheet 40, and the fastening member 60 and the back sheet 20 on which the absorbent core 30 is disposed to produce a diaper main body. That is, the fastening member 61 and the diaper main body 2 are joined by sandwiching the fixed end 61a of the fastening base member 61 between the side sheet 40 and the back sheet 20. The joining is preferably performed by pressure treatment with a roller or the like.

  F) It is preferable that the disposable diaper manufactured using a reactive urethane hot melt adhesive is cured at a humidity of 40% to 90% and 15 ° C to 30 ° C for about 120 hours. Curing is preferably performed by storing in a warehouse as a final product without requiring any special treatment. By curing under the above conditions, the moisture curing reaction of the reactive urethane hot melt adhesive proceeds and cures. As a result, a three-dimensional cross-linked structure is formed, and the heat resistant adhesive strength is expressed.

  Next, with reference to FIG. 7 thru | or FIG. 11, the process of apply | coating a hot-melt-adhesive to the fastening member 60 is demonstrated. In the configuration shown in FIG. 7 and the like, a case where the configuration shown in FIG. 5A is adopted as the configuration of the fastening member 60 will be described. Further, in the configuration shown in FIG. 7 and the like, the hot melt adhesive for bonding the fastening member 60 is applied to the skin surface side of the fastening member 60, but the hot melt adhesive is applied to the outer surface side of the side sheet 40. You may do it.

  Here, the fastening substrate continuum 146 shown in FIG. 7 is a strip-shaped material in which the left and right fastening substrates 61 are continuously connected in the longitudinal direction Y, and the central portion of the fastening substrate continuum 146 is virtually assumed. The left and right fastening base materials 61 are produced by dividing the partial continuous body into two left and right partial continuous bodies by a corrugated cut line 147 indicated by lines, and cutting each partial continuous body into predetermined dimensions. In the central portion of the fastening base material continuous body 146, the material for forming the first fastening member 63 is continuously connected in the longitudinal direction Y before being cut into the fastening base material 61. One fastening member continuous body 148 is joined by a joining means such as an adhesive. Then, in a state where the first fastening member continuous body 148 is joined, the fastening base material continuous body 146 is cut into the fastening base material 61, so that the first fastening member 63 is joined in advance. The base material 61 is produced.

  Application | coating of the hot-melt-adhesive to the fastening base material 61 is performed with respect to the fastening base material continuous body 146 before the fastening base material 61 is cut | disconnected. As a modified example, after the fastening base material continuous body 146 is divided into the left and right partial continuous bodies at the cut line 147, hot melt and adhesive may be applied.

  The hot melt adhesive is preferably applied to the fastening substrate continuous body 146 using a coater head 151 as shown in FIG. The coater head 151 is disposed in a state where adhesive discharge portions 152 and 153 described later for discharging hot melt adhesive are in contact with the coating surface (here, the surface of the fastening substrate continuous body 146), or slightly. It is a contact-type adhesive applicator arranged close to each other through a gap. Further, in the configuration shown in FIG. 8, it is assumed that the individual coater heads 151 are arranged in two hot melt adhesive application regions on both sides in the lateral direction X of the fastening base material continuous body 146. The hot melt adhesive application region may be performed by one coater head 151. As a modification, a non-contact type adhesive applicator such as a spiral applicator in which the adhesive discharge portions 152 and 153 for discharging the hot melt adhesive are arranged at a distance from the coating surface may be adopted.

  As shown in FIGS. 9 to 11, the coater head 151 has a plurality (for example, two) of adhesive discharge portions 152 and 153 from which hot melt adhesives of different types are discharged. Adhesive discharge parts 152 and 153 are arranged at positions corresponding to the adhesive application area. The reactive urethane hot melt adhesive and the non-reactive hot melt adhesive may be discharged from any of the adhesive discharge portions 152 and 153. Then, the coater head 151 is disposed so that the adhesive discharge portions 152 and 153 face the position where the adhesive application region of the fastening base material continuous body 146 is to be formed, and hot melt bonding is performed from the adhesive discharge portions 152 and 153. While discharging the agent, the fastening substrate continuous body 146 is transported in the transport direction parallel to the longitudinal direction Y, so that the hot melt adhesive is banded along the longitudinal direction Y at a predetermined position of the fastening substrate continuous body 146. Applied.

  The fastening substrate continuous body 146 to which the reactive urethane hot melt adhesive and the non-reactive urethane hot melt adhesive are applied is cut into the fastening substrate 61. And the part (fixed edge part) of the inward side of the horizontal direction X of the cut | disconnected fastening base material 61 is joined to the diaper main body 2 so that it may be pinched | interposed between the members which comprise the diaper main body 2.

  Next, a specific configuration example of the coater head 151 will be described. Various configurations can be adopted as the configuration of the coater head 151, and the configuration is not limited to the configuration described here. As shown in FIGS. 9 to 11, the coater head 151 includes first and second head portions 156 and 157 and a shim 158. The first and second head portions 156 and 157 are fixed in a state of facing each other with a shim 158 sandwiched therebetween.

  The shim 158 has a substantially plate shape, and a plurality of (here, two) adhesive discharge portions 152 and 153 are formed. In each of the adhesive discharge portions 152 and 153, a part of the lower edge of the shim 158 is lowered in a substantially comb shape to form one or a plurality of slits 159.

  An adhesive for supplying, for example, a reactive urethane hot melt adhesive to the adhesive discharge portion 152 at a portion of the surface of the first head portion 156 facing the shim 158 facing the adhesive discharge portion 152 of the shim 158 An agent supply recess 156a is provided. The supply of the adhesive to the adhesive supply recess 156a is performed via the supply path 156b. Further, for example, a non-reactive hot melt adhesive is supplied to the adhesive discharge portion 153 in a portion of the surface of the second head portion 157 facing the shim 158 facing the adhesive discharge portion 153 of the shim 158. Adhesive supply recesses 157a are respectively provided. The supply of the adhesive to the adhesive supply recess 157a is performed via the supply path 157b.

  In the configuration shown in FIG. 9 and the like, the two adhesive supply recesses 156a and 157a for supplying the adhesive to the adhesive discharge portions 152 and 153 are divided into two head portions 156 and 157. However, all of the two adhesive supply recesses 156a and 157a may be formed in any one of the head portions 156 and 157, and the other head portions 156 and 157 may be omitted.

  According to the adhesive application process as described above, the reactive urethane hot melt adhesive 72 and the non-reactive hot melt adhesive 55 to the fastening substrate 61 are simultaneously applied by one coater head 151. The manufacturing process can be simplified.

  A plurality of coater heads 151 may be arranged for each type of adhesive. For example, one of the reactive urethane hot melt adhesive 72 and the non-reactive hot melt adhesive 55 is applied with one coater head, and the other hot melt adhesive is applied with the second coater head. What should I do?

  Hereinafter, the present invention will be described in detail by way of examples. However, the present invention is not limited to the following examples, and all modifications and embodiments without departing from the gist of the present invention are not limited thereto. Included in range.

[Evaluation methods]
(Adhesion test)
A disposable diaper was manufactured by joining both side edges in the width direction in the rear part of the diaper main body and the fastening member with a reactive urethane hot melt adhesive. Using a disposable diaper after the lapse of a predetermined time after manufacture, a test piece having a length of 100 mm from the joint between the side sheet and the fastening member to the fastening member extending outward from the side sheet was produced with a width of 50 mm (see FIG. 12, test piece 90). A fastening member was attached to the upper chuck of the tensile tester (manufactured by A & D, Tensilon Universal Tester RTG-1210), and a side sheet was attached to the lower chuck so that the longitudinal direction of the test piece was the tensile direction. Next, the test piece was pulled in the direction of 180 degrees at a speed of 300 mm / min, and the stress was measured until the fastening member was peeled from the diaper body, and the maximum value of the stress was defined as the adhesive strength. The results are shown in Table 1. In addition, the adhesive force tested about each of the right and left fastening members of five disposable diapers, and showed it by the average value.

  As is clear from the results in Table 1, it can be seen that the joint using the reactive urethane hot melt adhesive has higher adhesive strength over time. This result has shown that the reactive urethane hot-melt-adhesive has expressed the adhesive force by moisture hardening reaction.

(Heat resistant adhesion test)
Using a disposable diaper that has passed for more than 5 days at room temperature after manufacturing, from the diaper main body positioned inward in the width direction from the fastening member, it is positioned outward in the width direction from the diaper main body through a portion where the fastening member and the diaper main body overlap. A test piece having a length of 100 mm including a region reaching the fastening member was produced with a width of 25 mm. Next, after attaching a weight of 500 g to the fastening member, the diaper main body side was lifted in a 40 ° C. atmosphere, and the time until the fastening member dropped away from the diaper main body was measured. The results are shown in Table 2. In addition, the peeling time tested for each of the right and left fastening members of the four disposable diapers, and indicated as an average value.

  The peel time of the joint using the reactive hot melt adhesive is 1000 minutes or more, and the peel time of the joint using the non-reactive hot melt adhesive is 73 minutes. From this result, it can be seen that the joint using the reactive hot melt adhesive is excellent in heat resistant adhesiveness.

In the adhesive strength test and the heat resistant adhesive strength test, a hot melt adhesive having the following characteristics was used.
[Reactive urethane hot melt adhesive A]
A) Melt viscosity 13,000-20000 mPa · s / 120 ° C.
B) Softening point 100-130 ° C
C) The number average molecular weight of the urethane prepolymer is 1,000 to 10,000.
D) The isocyanate group content (NCO%) in the urethane prepolymer is 1.7 to 5.0.
E) The ratio of the total isocyanate groups of the polyisocyanate and the total of the polyol (B) hydroxyl groups (hereinafter referred to as the NCO / OH ratio) is 1.1 to 5.0.
[Non-reactive hot melt adhesive B]
Non-reactive hot melt adhesive manufactured by Moresco (SBS block copolymer, melt viscosity 5200 mPa · s / 160 ° C, softening point 102 ° C)

  Moreover, since the disposable diaper of this invention uses the reactive urethane hot-melt-adhesive and the non-reactive urethane hot-melt-adhesive together, there is no shape loss at the time of manufacture.

1: disposable diaper, 2: diaper main body, 2a: front part, 2b: rear back part, 2c: crotch part, 10: top sheet, 20: back sheet, 30: absorbent core, 40: side sheet, 41: for side sheet Elastic member, 51: Elastic member for waist circumference, 52: Elastic member for foot circumference, 55: Hot melt adhesive, 60: Fastening member, 61: Fastening base material, 62: Knob part, 63: First fastening member, 70: second fastening member, 72: reactive urethane hot melt adhesive, 80: joint, 81: joint, 90: test piece

Claims (13)

A diaper body having an absorbent core;
Left and right fastening members respectively joined to both side edges of the rear portion of the diaper body and extending outward in the width direction from the diaper body;
First fastening members respectively provided on the skin surface side of the left and right fastening members;
A second fastening member provided on the outer surface side of the front portion of the diaper main body, the first fastening member being detachably fastened;
A disposable diaper, wherein the diaper main body and the fastening member are joined together by a cured product of a reactive urethane hot melt adhesive and a non-reactive hot melt adhesive.   At least one of the skin surface side and the outer surface side of the fixed end portion of the fastening member is joined to the diaper main body by a cured product of a reactive urethane hot melt adhesive and a non-reactive hot melt adhesive. The disposable diaper according to 1.   One of the skin surface side and the outer surface side of the fastening end of the fastening member is joined to the diaper body by a cured product of a reactive urethane hot melt adhesive and a non-reactive hot melt adhesive, and the other is non-reactive. The disposable diaper according to claim 1 or 2, wherein the disposable diaper is joined to the diaper main body only with a hot melt adhesive.   The disposable ratio according to any one of claims 1 to 3, wherein a mass ratio of a coating amount of the cured product of the reactive urethane hot melt adhesive and the non-reactive hot melt adhesive is 15/50 to 50/35. Diapers.   The disposable diaper according to any one of claims 1 to 4, wherein the non-reactive hot melt adhesive includes a rubber hot melt or an olefin hot melt.   The disposable diaper according to any one of claims 1 to 4, wherein a peeling time of a joint portion between the member constituting the diaper main body and the fastening member is 1000 minutes or more.   The disposable diaper according to any one of claims 1 to 6, wherein an adhesive strength of a joint portion between the member constituting the diaper main body and the fastening member is 10 N / 50 mm to 20 N / 50 mm. The coating amount of the cured product of the reactive urethane hot melt adhesive at the junction between the member and the fastening member constituting the diaper body, any one of claims 1 to 7, a 15g ^/ m ² ~50g / m 2 Disposable diapers described in 1. The coating amount of the non-reactive hot-melt adhesive at the junction between the member and the fastening member constituting the diaper body, according to any one of claims 1 to 8 is 35g ^/ m ² ~50g / m 2 Disposable diapers. A diaper body having an absorbent core;
Left and right fastening members respectively joined to both side edges of the rear portion of the diaper body and extending outward in the width direction from the diaper body;
First fastening members respectively provided on the skin surface side of the left and right fastening members;
A method for producing a disposable diaper having a second fastening member provided on the outer surface side of the front portion of the diaper main body, wherein the first fastening member is detachably fastened,
A method for producing a disposable diaper, characterized in that both side edges in the width direction in the rear part of the diaper main body and a fastening member are joined using a reactive urethane hot melt adhesive and a non-reactive hot melt adhesive. .   The manufacturing method of the disposable diaper of Claim 10 which sets the ratio of the coating amount of a reactive urethane hot-melt-adhesive and a non-reactive hot-melt-adhesive to 15 / 50-50 / 35. At the junction between the member and the fastening member constituting the diaper body, the manufacture of disposable diaper according to the coating amount of the reactive urethane hot melt adhesive, to claim 10 or 11, 15g ^/ m ² ~50g / m 2 Method. At the junction between the member and the fastening member constituting the diaper body, wherein the coating amount of the non-reactive hot-melt adhesives, to any one of claims 10 to 12 35g ^/ m ² ~50g / m 2 Manufacturing method for disposable diapers.

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