JP6647015B2 - Absorbent articles - Google Patents

Description

  The present invention relates to an absorbent article such as a disposable diaper.

  For absorbent articles such as disposable diapers, softening the absorbent body to make the entire article softer improves the fit when worn, improves the effect of suppressing leakage, and eliminates discomfort when worn. Very important. In recent years, in order to soften the absorbent body, for example, inventions have been made in which the entire absorbent body is designed to be thin or a non-woven fabric portion is provided in the absorbent body. For example, Patent Literature 1 and Patent Literature 2 disclose a technique relating to a disposable diaper in which a non-stacking portion is provided in an absorbent body.

JP 2006-247363 A JP 2012-034715 A

  According to the disposable diapers described in Patent Literature 1 and Patent Literature 2, since the non-stacking portion is provided in the absorbent body, it is easy to bend from the non-stacking portion, the absorber becomes soft, and the entire disposable diaper is used. Can be softened.

  However, when the absorbent absorbs the body fluid while wearing the diaper, the interior of the absorbent is broken or the absorbent is separated from the non-woven portion as a starting point, and the absorbent performance of the absorbent itself cannot be sufficiently exhibited. There was room for further improvement.

  In addition, in order to prevent breakage of the inside of the absorbent body after the absorbent body fluid has been absorbed, or separation of the absorbent body, for example, through the non-stacking portion, the absorbent located on the skin-facing surface side of the absorbent body When a large amount of adhesive is used to join the core wrap sheet that forms the body and the core wrap sheet that is located on the non-skin-facing surface side of the absorbent body, the rigidity of the portion that is located in the non-woven portion increases. , The discomfort at the time of wearing cannot be eliminated.

  Accordingly, an object of the present invention is to provide an absorbent article that can solve the above-mentioned disadvantages of the related art.

The present invention includes an absorbent body having an absorbent core containing an absorbent polymer and a covering material that wraps the absorbent core, and has a longitudinal direction corresponding to the front-rear direction of the wearer and a lateral direction orthogonal thereto. Divided into a ventral region arranged on the abdomen of the wearer when worn, a dorsal region arranged on the dorsal side of the wearer, and a crotch region arranged between the ventral region and the dorsal region An absorbent article, wherein the covering material is formed of a nonwoven fabric including a layer formed of long fibers and fixed by a heat-sealing portion, and the long fibers are formed by melting a thermoplastic resin made of a single resin. The nonwoven fabric forming the coating material is a single-layer fiber formed by uniformly spinning, and has a basis weight of 5 g / m ² or more and 20 g / m ² or less. In the crotch region, a non-stacking portion penetrating in the thickness direction extends in the vertical direction, In the portion, the covering material located on the skin-facing surface side of the absorbent core and the covering material located on the non-skin-facing surface side of the absorbent core are joined via a joint, and viewed in plan. The ratio of the area of the joining portion to the area of the non-stacking portion is 20% or more and 80% or less, and the pattern of the joining portion is formed from a circle or a polygon in plan view. It is an object of the present invention to provide an absorbent article having a dot shape, a linear shape, or a pattern obtained by combining these.

  According to the present invention, the entire absorbent article can be softened by softening the absorbent body, and even when the absorbent body fluid is absorbed during wearing, breakage of the interior of the absorbent body or separation of the absorbent body hardly occurs. The absorption performance of the absorber itself can be sufficiently exhibited.

FIG. 1 is a partially broken plan view in which a part of a deployable disposable diaper which is a preferred embodiment of the absorbent article of the present invention is partially broken. FIG. 2 is a sectional view taken along line II-II shown in FIG. FIG. 3 is a plan view of the absorbent body provided with the deployable disposable diaper shown in FIG. FIG. 4 is a graph showing the relationship between the seal strength and the seal area ratio when two nonwoven fabrics made of the same single resin thermoplastic resin are partially fused. FIG. 5 is a diagram for explaining a method for producing a measurement sample for obtaining the relationship between the seal strength and the seal area ratio in FIG. 4 and a method for measuring the seal strength using the produced measurement sample. FIG. 6 is a graph showing the relationship between the seal strength and the seal area ratio when two sheets of nonwoven fabric composed of long fibers having a core-sheath structure are partially fused. 7A to 7D are plan views of an absorbent body included in an absorbent article according to another embodiment of the present invention (a diagram corresponding to FIG. 3).

Hereinafter, the absorbent article of the present invention will be described with reference to the drawings based on a disposable diaper which is a preferred embodiment thereof.
As shown in FIGS. 1 to 3, the disposable diaper 1 of the present embodiment (hereinafter, also referred to as “diaper 1”) includes an absorbent core 41 containing an absorbent polymer and a covering material 42 wrapping the absorbent core 41. Absorbent body 4 having a vertical direction X corresponding to the front-back direction of the wearer and a horizontal direction Y orthogonal to the wearer 4, and has an abdominal area A disposed on the abdomen of the wearer when worn, It is divided into a dorsal region B arranged on the dorsal side and a crotch region C arranged between the ventral region A and the dorsal region B.

  In the present specification, the “skin-facing surface” is a surface of the diaper 1 or a component thereof (for example, the absorber 4) that faces the wearer's skin when worn, and the “non-skin-facing surface” The surface of the diaper 1 or a component thereof, which is directed to the side (clothing side) opposite to the skin side of the wearer when worn. The vertical direction X corresponds to the direction (longitudinal direction) along the long side of the diaper 1 or its constituent members (such as the absorber 4), and the horizontal direction Y corresponds to the diaper 1 or its constituent members (such as the absorber 4). In the width direction. Further, a thickness direction which is a vertical direction orthogonal to a plane direction including a vertical direction X and a horizontal direction Y will be described as a Z direction. The abdominal area A is an area located on the wearer's abdomen when worn, the dorsal area B is an area located on the wearer's dorsal when worn, and the crotch area C is an abdominal area. It is a region arranged between A and the back region B.

  When the diaper 1 is divided into the abdominal region A, the dorsal region B, and the crotch region C in the longitudinal direction X, as shown in FIG. 1, the length in the longitudinal direction X (longitudinal direction) is divided into three. The middle can be divided into a crotch region C, the abdomen into an abdominal region A, and the dorsal region into a dorsal region B.

  More specifically, the diaper 1 is a so-called unfoldable disposable diaper, and as shown in FIGS. 1 and 2, a liquid-permeable top sheet 2 forming a skin-facing surface, and a liquid-resistant surface sheet forming a non-skin-facing surface. The apparatus includes a transparent back sheet 3 and a liquid-retaining absorber 4 disposed between the sheets 2 and 3. As shown in FIG. 1, the diaper 1 has a shape that is long in the vertical direction X in plan view. The top sheet 2 and the back sheet 3 each have a size larger than the absorber 4 and extend outward from the periphery of the absorber 4.

  In the diaper 1, as shown in FIG. 1, the top sheet 2 and the back sheet 3 extend outward from the entire circumference of the absorber 4 that is long in the longitudinal direction X, that is, both right and left side edges and front and rear end edges. I have. The top sheet 2 of the diaper 1 has the same dimension in the vertical direction X as the dimension in the vertical direction X of the back sheet 3, but the dimension in the horizontal direction Y is smaller than the dimension in the horizontal direction Y of the back sheet 3. Has become. The top sheet 2 and the back sheet 3 are joined to each other directly or with another member interposed therebetween at an extending portion extending outward from the peripheral edge of the absorber 4, and hold and fix the absorber 4. are doing.

  As shown in FIGS. 1 and 2, in the diaper 1, a leakage prevention cuff forming sheet 52 having an elastic member 51 fixed in an extended state in the vertical direction X is provided on each of both sides along the vertical direction X. The pair of leak-preventing cuffs 5 and 5 are formed by the contraction force of the elastic member 51. As shown in FIGS. 1 and 2, in the diaper 1, leg elastic members 53 for forming leg gathers are disposed on the both sides along the vertical direction X in a state of being extended in the vertical direction X, and the leg elasticity is increased. Leg gathers are formed by the contraction force of the member 53. As shown in FIG. 1, in the diaper 1, a waist elastic member 54 for forming waist gathers extends in the lateral direction Y at the end in the vertical direction X on the back region B side, as shown in FIG. The waist gathers are formed by the contraction of the waist elastic member 54.

  Further, as shown in FIG. 1, the diaper 1 is provided with a pair of fastening tapes 6, 6 that extend outward in the horizontal direction Y from both sides along the vertical direction X of the back region B. A fastening portion (not shown) made of a male member of a mechanical hook-and-loop fastener is attached to the fastening tape 6. Further, in the diaper 1, a fastening region 7 made of a female member of a mechanical surface fastener is formed on the non-skin facing surface of the abdominal region A (the non-skin facing surface of the back sheet 3). The attachment region 7 is formed by joining a female member of a mechanical surface fastener to the non-skin-facing surface of the back sheet 3 by a known joining means (for example, an adhesive or a heat seal). The fastening portion of the tape 6 can be detachably fastened.

  As described above, the absorber 4 has the absorbent core 41 containing the absorbent polymer, and the covering material 42 surrounding the absorbent core 41. In the diaper 1, as shown in FIG. 1, the absorber 4 has a shape that is long in the same direction as the vertical direction X of the diaper 1, and the absorbent core 41 having a liquid holding property that is long in the vertical direction X It is formed by covering with a transparent covering material 42. The covering material 42 keeps the shape of the absorbent core 41 by enclosing the absorbent core 41, and prevents the components of the absorbent core 41 such as the superabsorbent polymer from falling off.

In the absorbent core 41, a non-stacking portion 43 penetrating in the thickness direction Z extends at least in the crotch region C in the longitudinal direction X. Here, that the non-stacking portion 43 extends at least to the crotch region C means that the non-stacking portion 43 extending in the vertical direction X slightly covers the crotch region C. In addition, the non-stacking portion 43 includes not only a through hole in which a material (core forming material) for forming an absorbent core does not exist at all but also a core forming material of about 30 g / m ² from the viewpoint of achieving the same effect. It includes the case where it is slightly present. In the diaper 1, as shown in FIGS. 1 and 2, two non-stacking portions 43, 43 extend in the vertical direction X from the abdominal region A to the dorsal region B, including the entire crotch region C. It is formed to extend in a belt shape in parallel.

The basis weight of the absorbent core 41 excluding the non-laid fiber portion 43 is preferably 50 g / m ² or more and 500 g / m ² or less, and more preferably 100 g / m ² or more and 450 g / m ² or less.
The area of the non-stacking portion 43 (the total area of the two non-stacking portions 43 in the diaper 1) (S1) is preferably 5 cm ² or more, more preferably 10 cm ² or more, and more preferably 80 cm ² or less. Is preferably 60 cm ² or less, more preferably 5 cm ² or more and 80 cm ² or less, and more preferably 10 cm ² or more and 60 cm ² or less. Here, the area of each non-stacking portion 43 means the area of a portion surrounded by the contour of the non-stacking portion 43 when the absorbent core 41 is viewed in plan.

  In the diaper 1, when the absorbent core 41 is viewed in a plan view, the ratio ((S1 / S0) × 100) of the area (S1) of the non-stacking portion 43 to the area (surface area) (S0) of the absorbent core 41 is: The discomfort at the time of wearing the diaper 1 is suppressed, the fitting property is improved, the diffusion of the bodily fluid in the vertical direction X is easily promoted, and the feeling of the bodily fluid is improved. From the viewpoint of improving suppression of, the content is preferably 2% or more, more preferably 5% or more, preferably 30% or less, more preferably 25% or less, and specifically, It is preferably from 2% to 30%, more preferably from 5% to 25%. Here, the area (surface area) (S0) of the absorbent core 41 refers to the area of the entire absorbent core 41 when the absorbent core 41 is viewed in plan, and the non-stacking portion included in the absorbent core 41. 43 (S1).

  In the diaper 1, the covering material 42 is formed as a single piece as shown in FIG. Preferably, the covering material 42 is longer than the length of the absorbent core 41 in the longitudinal direction X in the longitudinal direction X, and in the lateral direction Y, as shown in FIG. Of the absorbent core 41, and further wrapped around the non-skin-facing surface side of the absorbent core 41 so as to overlap the non-skin-facing surface of the absorbent core 41 at the center in the lateral direction Y to wrap the absorbent core 41. In.

  The covering material 42 is formed of a nonwoven fabric including a layer formed of long fibers and fixed by a heat-sealing portion. Such a nonwoven fabric includes not only a spunbonded nonwoven fabric in which a web made of long fibers is fixed by a heat-sealed portion, but also a laminated nonwoven fabric in which a spunbond layer formed of long fibers is stacked and fixed by a heat-sealed portion. It is. Examples of such a laminated nonwoven fabric include a spunbond-meltblown-spunbond laminated nonwoven fabric (SMS nonwoven fabric) and a spunbond-meltblown-meltblown-spunbond nonwoven fabric (SMMS nonwoven fabric). When the covering material 42 is made of the nonwoven fabric as described above, the absorbent body 4 itself tends to be softer than a mount such as tissue paper or the like generally used for the covering material, and can be joined when dry and when wet. Seal) Strength tends to increase. In addition, since the strength of the sheet itself when wet is particularly high, the coating material 42 is hardly torn by the movement of the wearer when the diaper 1 is worn, hardly torn after urination, less likely to leak body fluid, or returned to fluid. Is unlikely to occur.

  In the diaper 1, the longitudinal direction X of the diaper 1, that is, the absorber 4, matches the MD direction along the orientation direction of the fibers when the main orientation direction of the constituent fibers of the covering material 42 is viewed. 1, that is, the lateral direction Y of the absorber 4 matches the CD direction orthogonal to the MD direction.

  The long fibers constituting the covering material 42 are single-layer fibers formed by uniformly spinning a thermoplastic resin made of a molten single resin. Here, the “single-layer fiber” does not include a concentric or eccentric core-sheath fiber or a side-by-side fiber, and the fiber formed by spinning has a uniform single-layer structure. Fiber. Further, as the single resin, a polyethylene resin composed of a homopolymer, a polypropylene resin composed of a homopolymer, a polyethylene terephthalate resin composed of a homopolymer, and the like are exemplified.From the viewpoint of spinnability, a polypropylene resin composed of a homopolymer is preferably used. Can be The fiber diameter of the long fiber is preferably 0.5 dtex or more, more preferably 0.8 dtex or more, preferably 5.0 dtex or less, more preferably 4.0 dtex or less.

The nonwoven fabric constituting the covering material 42 has a basis weight of 5 g / m ² or more, preferably 7 g / m ² or more, and more preferably 8 g / m ² or more from the viewpoint of strength, softness, and cost. More preferably, it is 20 g / m ² or less, preferably 15 g / m ² or less, more preferably 12 g / m ² or less, and specifically, 5 g / m ² or more and 20 g / m ^2. less and, more preferably it is preferably 7 g / ^{m 2} or more 15 g / ^{m 2} or less, 8 g / ^{m 2} or more 12 g / ^{m 2} or less.

  In the non-stacking portion 43, the covering material 42 located on the skin-facing surface side of the absorbent core 41 and the covering material 42 located on the non-skin-facing surface side of the absorbent core 41 are joined via the joint 8. ing. The joining portion 8 can be formed by melting constituent fibers of the covering material 42 on the skin facing surface side and the covering material 42 on the non-skin facing surface side and fusing the covering materials 42 together, or The coating material 42 can be formed by applying an adhesive between the coating material 42 on the side and the coating material 42 on the non-skin-facing surface side and joining the coating materials 42 together. Further, as described above, since the long fibers constituting the coating material 42 are single-layer fibers formed by uniformly spinning a thermoplastic resin made of a single molten resin, the coating on the skin-facing surface side is performed. The coating materials 42 can be formed by pressing the coating materials 42 by pressure without applying heat to the material 42 and the coating material 42 on the non-skin-facing surface side.

  In the diaper 1, as shown in FIGS. 1 and 3, when viewed in a plan view, the pattern of the bonding portion 8 is a dot-shaped pattern formed from a circle. The pattern of the bonding portion 8 of the diaper 1 is a pattern distributed and arranged in the vertical direction X. The area of the joining section 8 (the total area of the plurality of joining sections 8 arranged in the two non-stacking sections 43 in the diaper 1) (S2) is appropriately changed according to the area of the non-stacking section 43. Can be.

  As shown in FIG. 1 and FIG. 3, the diaper 1 is viewed from above, and the ratio of the area (S2) of the joining portion 8 to the area (S1) of the non-stacking portion 43 ((S2 / S1) × 100). Is from 20% or more, preferably from 25% or more, more preferably from 30% or more, from the viewpoint of achieving both the stable joining strength of the joining portion 8 and the softness of the joining portion 8. %, Preferably 75% or less, more preferably 70% or less, particularly preferably less than 50%. Specifically, it is 20% or more and 80% or less, preferably 25% or more and 75% or less, more preferably 30% or more and 70% or less, and particularly preferably 30% or more and less than 50%. preferable. Here, the area of each joint 8 means the area of a portion surrounded by the outer periphery of the joint 8 when the joint 8 is viewed in plan.

  Further, the present inventor has found that if the thermoplastic resin forming the covering material 42 is a single resin, the joining portion 8 is formed by fusion bonding or pressure bonding other than bonding with an adhesive. It has been found that the bonding (seal) strength is obtained at a constant strength irrespective of the seal area, and is a strength that can withstand actual use. As described above, the bonding portion 8 can be formed by bonding with an adhesive, fusion or compression without using an adhesive, but is formed by fusion or compression from the viewpoint of cost reduction and workability. It is preferable to press-bond and form from the viewpoint of suppressing investment in processing equipment and workability.

  FIG. 4 is a plot of the relationship between the sealing strength and the sealing area ratio of the joint 8 when the covering members 42 made of a single resin thermoplastic resin are partially fused. Specifically, as shown in FIG. 5A, nonwoven fabrics used for two covering materials 42 each having a length of 200 mm and a width of 50 mm in the width direction are prepared, and they are overlapped, and a central portion D of the overlapped sample is prepared. Then, a plurality of heat-sealing seal wires 44 each having a length of 30 mm and a seal width of 2 mm are arranged at predetermined intervals (pitch) in the width direction and joined (sealed) to produce a measurement sample SP. Such a measurement sample SP is manufactured by changing the interval (pitch) in the width direction of the heat-sealing seal line in various ways, and a plurality of measurement samples having different seal area ratios are manufactured. Next, as shown in FIG. 5 (b), the bonding (seal) strength of each of the manufactured measurement samples SP is measured by using a tensile tester (for example, Orientec Co., Ltd.) so that the longitudinal direction of the measurement sample SP is the tensile direction. It is attached to a chuck (10 mm between chucks) of a Tensilon tensile tester (RTA-100) and pulled at a tensile speed of 300 mm / min, and the maximum load point (seal strength) until the measurement sample breaks is measured. FIG. 4 is a plot of the relationship between the seal strength and the seal area ratio measured in this manner. In FIG. 6, two nonwoven fabrics composed of long fibers having a core-sheath structure composed of a polyethylene terephthalate resin and a polyethylene resin are prepared, and the seal strength and the seal strength of a measurement sample produced in the same manner as above are prepared. The relationship with the area ratio is plotted.

  Generally, as shown in FIG. 6, the sealing strength increases with an increase in the sealing area ratio. The cause of such a phenomenon will be considered. When heat-sealing (sealing) is applied to a non-woven fabric having a core-in-sheath structure, a film is formed at the fused (sealed) portion, but the high melting point fiber forming the core maintains the fiber shape in the cross section. Since each of the nonwoven fabrics constituting the fusion (sealing) portion has little damage due to heat at the fusion (sealing) portion, when peeling is performed as shown in FIG. It is considered that peeling occurs, and as a result, peeling strength (joining strength) increases in proportion to the sealing area. However, as shown in FIG. 4, the present inventor found that when nonwoven fabrics made of the same single resin thermoplastic resin were fused together, as shown in FIG. It was found that it was almost constant regardless of the situation. Considering the cause of such a phenomenon, it is impossible to maintain the fiber structure at the fused (seal) portion because the fibers are made of the same single resin, and the fused (seal) portion is It is considered that the constituent nonwoven fabrics are greatly affected by heat in the fusion (sealing) portion. Generally, if the peeling shown in FIG. 5 is performed under such a large influence of heat, the damaged seal portion is immediately broken, and the seal strength is not expressed (extremely weak). However, the present inventor has found that when there is any width in the fusion (sealing) portion, the influence of heat at the time of fusion (sealing) is located outside the outline of the wide fusion (sealing) portion in the width direction. It was found that a weakly fused portion was formed, and that a fused portion in which a long fiber was melted and formed into a film without a fiber shape was formed within the outline of the fused (seal) portion. In addition, the present inventor has found that in the weakly fused portion outward in the width direction, the fibers are partially fused with each other without losing the fiber shape of the long fiber. It has been found that at the same time as the fracture occurs from the fused portion, the fused portion itself formed into a film is destroyed, and subsequently the two nonwoven fabrics used are destroyed. Therefore, the bonding (seal) strength when nonwoven fabrics composed of a single resin thermoplastic resin are fused is not the peel strength of the fusion (seal) part, but the fusion (seal) part. It is considered that the strength became substantially constant irrespective of the sealing area because the breaking strength was equivalent to the breaking strength of each nonwoven fabric.

  Therefore, if the thermoplastic resin constituting the non-woven fabric used for the covering material 42 is a single resin, a constant bonding (seal) strength can be obtained regardless of the sealing area, and a small width can be formed at the fusion-bonded (seal) portion. It is presumed that if there is, a peel strength between the nonwoven fabrics that can withstand actual use can be obtained. As the non-woven fabric used for the covering material 42, those made of various commercially available resins can be used. However, from the viewpoint that a strong bond can be obtained only by pressure without applying heat, homopolymer, which is a single resin, is used. Most preferably, a spunbonded nonwoven fabric formed using a polypropylene resin made of a polymer is used. Further, if the pattern of the bonding portion 8 is a pattern distributed and arranged in the vertical direction X, an external force is applied to the diaper 1 in the horizontal direction Y as compared with a single pattern continuous in the vertical direction X. At that time, the existence ratio of the nonwoven fabric to be broken tends to increase, and it is presumed that peel strength between the nonwoven fabrics that can endure actual use is easily obtained. This is because when the diaper 1 is assumed to be worn, especially at the crotch part, the diaper 1 is directed toward a virtual center line (not shown) obtained by bisecting the diaper 1 in the lateral direction Y by the movement of right and left legs. Even when the absorbent core 41 is pressed in the direction of the lateral direction Y, the absorbent core 41 is hardly torn from the joint portion 8 joining the covering material 42 on the skin-facing surface side and the covering material 42 on the non-skin-facing surface side. It is presumed that the covering material 42 covering the 41 becomes difficult to be torn.

When the joining portion 8 is formed by performing fusion or pressure bonding without using an adhesive, the joining strength (SW) of the joining portion 8 when wet is determined by the movement of the wearer 42 when the wearer wears the diaper 1. It is preferably 2.0 N / 30 mm or more, more preferably 3.0 N / 30 mm or more, and more preferably 20 N / 30 mm or less, from the viewpoint that tearing hardly occurs and tearing after urination hardly occurs. It is more preferably 15 N / 30 mm or less, specifically, preferably 2.0 N / 30 mm or more and 20 N / 30 mm or less, more preferably 3.0 N / 30 mm or more and 15 N / 30 mm or less.
In addition, from the same viewpoint, the bonding strength (SD) of the bonding portion 8 when dry is preferably 2.0 N / 30 mm or more, more preferably 3.0 N / 30 mm or more, and more preferably 20 N / 30 mm or less. Is preferably 15 N / 30 mm or less, more preferably 2.0 N / 30 mm or more and 20 N / 30 mm or less, and more preferably 3.0 N / 30 mm or more and 15 N / 30 mm or less. Is more preferred.
The joint strength (SW) of the joint 8 when wet and the joint strength (SD) of the joint 8 when dry are measured by the following methods.

<Measurement method of bonding strength>
The top sheet 2 and the back sheet 3 are removed from the diaper 1, and the absorbent core 4 (see FIG. 3) formed by wrapping the absorbent core 41 with the covering material 42 is taken out. As illustrated in FIG. 3, a rectangular measurement sample precursor that is long in the lateral direction Y is cut out at a position overlapping the non-stacking portion 43 when the absorber 4 is viewed in a plan view. The size of the cut sample precursor for measurement is 150 mm in the horizontal direction Y and 30 mm in the vertical direction X. Next, an excess material, for example, the absorbent core 41 or the like is removed from the cut-out measurement sample precursor, and the covering material 42 located on the skin-facing surface side of the absorbent core 41 and the non-skin of the absorbent core 41 are removed. A measurement sample in a state where the covering material 42 located on the facing surface side is joined via the joint 8 is produced. Using a tensile tester (for example, Tensilon tensile tester “RTA-100” manufactured by Orientec Co., Ltd.) under an evaluation environment of room temperature 20 ° C. and humidity 60% RH, the measurement sample was prepared. A 180 ° peel test (pulling speed: 300 mm / min, gap between chucks: 30 mm) is performed in the transverse direction Y, that is, in the CD direction of the constituent fibers of the coating material, and the maximum load point (bonding strength) until the measurement sample breaks is measured. (Measurement of bonding strength of bonding portion 8 at dry time).
On the other hand, the measurement of the bonding strength of the bonding part 8 when wet is the same as the measurement of the bonding strength of the bonding part 8 when dry after immersion in ion-exchanged water at 22 ° C., wiping off excess water with a tissue. Then, it is measured using a tensile tester.

The ratio ((SD / SW) × 100) of the joining strength (SD) of the joining part 8 in the dry state to the joining strength (SW) of the joining part 8 in the wet state is determined by the covering material due to the movement of the wearer when the diaper 1 is worn. 42 is preferably 80% or more, and more preferably 85% or more, from the viewpoint that tearing of 42 is hard to occur and tearing after urination hardly occurs. The upper limit is 100%.
Here, when the joint 8 is formed using an adhesive, the adhesive is affected by water, so that the wet joint strength (SW) is lower than the dry joint strength (SD). Therefore, there is a possibility that a problem such as peeling of a joint portion occurs during use. On the other hand, when an adhesive is not used, that is, when the bonding portions 8 are formed by fusing or pressing the covering materials 42 together, the bonding state of the bonding portions is hardly affected by water. Since the strength (SW) is almost the same as that in the dry state (SD), peeling from the joint 8 during use hardly occurs. Furthermore, when introducing the adhesive, capital investment is required, and there are also problems in terms of cost and productivity such as strike-through. For the above reasons, it is desirable to form by fusion or pressure bonding without using an adhesive.

  In the diaper 1, the topsheet 2 and the covering material 42 located on the skin-facing surface side of the absorbent core 41 are bonded with an adhesive. Further, the back sheet 3 and the covering material 42 located on the non-skin-facing surface side of the absorbent core 41 are bonded with an adhesive.

The material for forming each part of the disposable diaper 1 described above will be described.
As the top sheet 2, the back sheet 3, the leak-proof cuff forming sheet 52, and the like, various kinds of articles conventionally used for absorbent articles such as disposable diapers can be used without any particular limitation. For example, as the topsheet 2, a single-layer or multilayer nonwoven fabric, an apertured film, or the like can be used. As the back sheet 3, a moisture-permeable resin film or the like can be used. Further, as the leak-proof cuff forming sheet 52, a water-repellent single-layer or multi-layer nonwoven fabric or the like can be used.

  As the absorbent core 41 constituting the absorbent body 4, various types of absorbent cores conventionally used for absorbent articles such as disposable diapers can be used, provided that the absorbent core 41 has an absorbent property for absorbing bodily fluids such as urine. The type is not particularly limited, and examples thereof include absorbent materials such as superabsorbent polymers and ground pulp. As the superabsorbent polymer, various types of diapers conventionally used in this type of diaper can be used, such as sodium polyacrylate, (acrylic acid-vinyl alcohol) copolymer, and sodium polyacrylate crosslinked. , A (starch-acrylic acid) graft polymer, a (isobutylene-maleic anhydride) copolymer and a saponified product thereof, potassium polyacrylate, and cesium polyacrylate, and the like. Two or more kinds can be used as a mixture.

  Examples of the elastic member (the elastic member 51 for forming the leak-proof cuff 5, the leg elastic member 53, the waist elastic member 54, and the like) include synthetic rubber such as styrene-butadiene, butadiene, isoprene, and neoprene, natural rubber, EVA, and the like. Stretchable polyolefin, polyurethane and the like can be mentioned. Examples of the form of the elastic member include a thread (thread rubber or the like) having a rectangular, square, circular, oval, or polygonal cross section, a string (flat rubber or the like), or a multifilament type thread. It can be preferably used.

The fastening portion forming each fastening tape 6 can be used without any particular limitation as long as it is generally used for absorbent articles such as disposable diapers. For example, as the fastening part, "Magic Tape (registered trademark)" (manufactured by Kuraray), "Quicklon (registered trademark)" (manufactured by YKK), "Majicloth (registered trademark)" (manufactured by Kanebo Bell Touch) And the like.
The attachment region 7 can be used without any particular limitation as long as it is usually used for absorbent articles such as disposable diapers. For example, as the attachment region 7, a synthetic resin such as polyethylene, polypropylene, or polyethylene terephthalate, or a nonwoven fabric made of a composite material of two or more of these synthetic resins can be used.

  For fixing each member, an adhesive, heat fusion, pressure bonding, or the like is used. The adhesive to be used can be used without any particular limitation as long as it is usually used for absorbent articles such as disposable diapers. For example, a hot melt adhesive can be used. Examples of the hot melt adhesive include blocks such as styrene-isoprene-styrene block copolymer (SIS), styrene-butadiene-styrene block copolymer (SBS), and styrene-ethylene-butylene-styrene copolymer (SEBS). Copolymer-based hot melt adhesives may be used. As the heat fusion and pressure bonding, any material can be used without particular limitation as long as it is used for an absorbent article such as a disposable diaper. For example, the nonwoven fabric 43 having a shape pattern penetrating in the thickness direction Z was used. A rotating roll, a high frequency seal, or an ultrasonic seal can be used.

The operation and effect when the diaper 1 of the embodiment of the present invention described above is used will be described.
As shown in FIGS. 1 to 3, the diaper 1 has a non-stacking portion 43 extending in a vertical direction X in a crotch region C of an absorbent core 41 constituting the absorber 4. The constituent covering material 42 is formed of a nonwoven fabric having a predetermined basis weight. With these two configurations, the absorber 4 can be softened, and the entire diaper 1 can be softened. In the non-stacking portion 43 of the absorber 4, the covering material 42 located on the skin facing surface side of the absorbent core 41 and the covering material 42 located on the non-skin facing surface side of the absorbent core 41 are joined. 8, the ratio of the area of the joining portion 8 to the area of the non-stacking portion 43 is a predetermined ratio, and the pattern of the joining portion 8 is a dot-shaped pattern. Therefore, even if the absorbent body 4 absorbs body fluids while the diaper 1 is worn, the inside of the absorbent body 4 is not easily broken or the absorbent body 4 is hardly divided, and the absorbing performance of the absorbent body 4 itself can be sufficiently exhibited.

  In the diaper 1, the coating material 42 is formed of a nonwoven fabric including a layer formed of long fibers and fixed by a heat-sealing portion, and the long fibers are formed of a thermoplastic resin made of a molten single resin. Is a single-layer fiber formed by spinning uniformly. Therefore, the joining portion 8 can be formed by performing fusion or pressure bonding without using an adhesive. If the bonding portion 8 is formed by fusing or press-bonding the nonwoven fabric including the layer formed from the long fiber of the single-layer fiber and fixed by the heat-fusion portion, as shown in FIG. The bonding (seal) strength of the diaper 1 can be obtained with a constant strength irrespective of the seal area and is a strength that can withstand actual use. The inside of the absorber 4 or the breakage of the absorber 4 is less likely to occur, and the absorption performance of the absorber 4 itself can be more sufficiently exhibited. Further, as described above, since the bonding portion 8 is a dot-shaped pattern and does not bond the entire non-stacking portion 43, the bonding portion 8 itself does not become hard, and urination is performed. When the core 41 swells, the swelling is less likely to be inhibited.

The absorbent article of the present invention is not limited to the diaper 1 of the present embodiment described above, and can be appropriately changed.
For example, in the diaper 1, when viewed in a plan view as shown in FIGS. 1 and 3, the pattern of the bonding portion 8 is a dot-like pattern formed from a circle, but as shown in FIG. It may be formed in a dot-like pattern formed from a polygon, and may be a pattern distributed and arranged in the vertical direction X. Further, as shown in FIGS. 7B and 7C, the joining portion 8 may be formed in a pattern formed from a linear shape, and may be a pattern distributed and arranged in the vertical direction X. . Preferably, the linear joining portion 8 shown in FIG. 7B is formed so as to extend in parallel with the horizontal direction Y from one side edge along the vertical direction X of each non-stacking portion 43 to the other side edge. The non-stacking portions 43 are arranged at regular intervals in the vertical direction X and are dispersed in the vertical direction X. Also, preferably, the linear joining portion 8 shown in FIG. 7C extends from one side edge along the vertical direction X of each non-laid fiber portion 43 toward the other side edge in parallel with the horizontal direction Y. It is formed so as to intersect the imaginary line, is arranged at a certain interval in the vertical direction X of the non-stacking portion 43, and is dispersedly arranged in the vertical direction X. Also, as shown in FIG. 7D, the joining portion 8 is formed in a pattern formed from a linear shape, and the linear joining portion 8 is formed from one end of each non-stacking portion 43 in the vertical direction X. It may be formed so as to extend in the vertical direction X toward the other end, and may be arranged at a certain interval in the horizontal direction Y of the non-stacking portion 43. Further, the pattern of the joining portion 8 may be a pattern formed by combining dots or bands formed from a circle or a polygon.
In the non-stacking portion 43, the coating material 42 located on the skin-facing surface side of the absorbent core 41 and the non-skin facing surface side of the absorbent core 41 are located in both the vertical direction X and the horizontal direction Y. Due to the presence of the non-joined portion where the coating material 42 is not joined, when urination is performed and the absorbent core 41 swells, the swelling of the absorbent core 41 is not hindered, and good absorbency can be secured. From the viewpoint of the above, and from the viewpoint of the softness of the non-stacking portion 43 when the diaper 1 is used, the pattern of the joining portion 8 is a dot-shaped pattern formed from the circle shown in FIG. 1 or FIG. It is preferable that the pattern is a dot pattern formed from the polygons shown in FIG. In addition, from the viewpoint that the joining portion 8 is formed by a rotating roll having the above-described pattern, and from the viewpoint of its wear resistance and molding stability, the pattern of the joining portion 8 is particularly formed from the circle shown in FIG. A dot-shaped pattern is preferred.

  As shown in FIG. 2, the covering material 42 of the diaper 1 is formed of one sheet, but the skin facing surface side of the absorbent core 41 is covered with the first covering material, and the non-skin facing surface of the absorbent core 41 is not covered. The surface side may be covered with a second second covering material to wrap the absorbent core 41.

  In addition, the absorbent article of the present invention is not limited to an expandable disposable diaper, and widely covers articles used for absorbing liquid discharged from the human body, such as pants-type disposable diapers, sanitary napkins, and sanitary shorts. Etc. are also included.

  With respect to the embodiment of the present invention described above, the following absorbent article is further disclosed.

<1>
An absorbent body having an absorbent core containing an absorbent polymer and a covering material surrounding the absorbent core, the absorbent body having a longitudinal direction corresponding to the front-rear direction of the wearer and a lateral direction orthogonal thereto, and Absorbent article divided into a ventral region arranged on the ventral side, a dorsal region arranged on the back of the wearer, and a crotch region arranged between the ventral region and the dorsal region. So,
The coating material is composed of a nonwoven fabric including a layer formed of long fibers and fixed by a heat-sealing portion, and the long fibers are formed by uniformly spinning a thermoplastic resin made of a molten single resin. Is a single-layer fiber,
The nonwoven fabric constituting the covering material has a basis weight of 5 g / m ² or more and 20 g / m ² or less,
In the absorbent core, at least the crotch region, a non-stacking portion penetrating in the thickness direction extends in the vertical direction,
In the non-stacking portion, the covering material located on the skin-facing surface side of the absorbent core and the covering material located on the non-skin-facing surface side of the absorbent core are joined via a joining portion. Yes,
In plan view, the ratio of the area of the joining portion to the area of the non-stacking portion is 20% or more and 80% or less,
An absorbent article in a plan view, wherein the pattern of the bonding portion is a dot or band formed from a circle or a polygon, or a pattern combining these.

<2>
The nonwoven fabric constituting the covering material has a basis weight of 5 g / m ² or more, preferably 7 g / m ² or more, more preferably 8 g / m ² or more, and 20 g / m ² or less, preferably 15 g or more. / M ² or less, more preferably 12 g / m ² or less, the absorbent article according to <1>.
<3>
The absorbent article according to <1> or <2>, wherein the pattern of the bonding portion is a pattern dispersedly arranged in a vertical direction.
<4>
The ratio of the joining strength of the joint when dry to the joining strength of the joint when wet is 80% or more,
The absorbent article according to any one of <1> to <3>, wherein the joining strength of the joining part when wet and the joining strength of the joining part when dry are 2.0 N / 30 mm or more, respectively. . <5>
The joining part is formed by pressing the covering material located on the skin facing surface side of the absorbent core and the covering material located on the non-skin facing surface side of the absorbent core in <1>. The absorbent article according to any one of <4> to <4>.
<6>
The basis weight of the absorbent core excluding the non-laid fiber portion is 50 g / m ² or more and 500 g / m ² or less, preferably 100 g / m ² or more and 450 g / m ² or less. The absorbent article according to any one of the above.
<7>
The area (S1) of the non-stacking portion is 5 cm ² or more, preferably 10 cm ² or more, and is 80 cm ² or less, preferably 60 cm ² or less. Absorbent articles.
<8>
When the absorbent core is viewed in plan, the ratio ((S1 / S0) × 100) of the area (S1) of the non-laid fiber portion to the area (S0) of the absorbent core is 2% or more, preferably 5% or more. % Or more and 30% or less, preferably 25% or less, the absorbent article according to any one of the above <1> to <7>.

<9>
The fiber diameter of the long fiber is 0.5 dtex or more, preferably 0.8 dtex or more, and 5.0 dtex or less, preferably 4.0 dtex or less. Absorbent articles.
<10>
The absorbent article according to any one of <1> to <9>, in plan view, wherein the pattern of the bonding portion is a dot-shaped pattern formed from a circle or a polygon.
<11>
The absorbent article according to <10>, wherein in plan view, the pattern of the bonding portion is a dot-shaped pattern formed from a circle.
<12>
In plan view, the ratio ((S2 / S1) × 100) of the area (S2) of the joining portion to the area (S1) of the non-stacking portion is 20% or more, preferably 25% or more, and more preferably. Is 30% or more, 80% or less, preferably 75% or less, more preferably 70% or less, particularly preferably less than 50%, the absorbent article according to any one of the above <1> to <11>. .
<13>
The bonding strength (SW) of the bonding portion when wet is 2.0 N / 30 mm or more, preferably 3.0 N / 30 mm or more, and 20 N / 30 mm or less, preferably 15 N / 30 mm or less. The absorbent article according to any one of <12>.

<14>
The joining strength (SD) of the joined portion when dry is 2.0 N / 30 mm or more, preferably 3.0 N / 30 mm or more, and 20 N / 30 mm or less, preferably 15 N / 30 mm or less. The absorbent article according to any one of <13>.
<15>
The ratio ((SD / SW) × 100) of the joining strength (SD) of the joining part when dry to the joining strength (SW) of the joining part when wet is 80% or more, preferably 85% or more. The absorbent article according to any one of <1> to <14>.
<16>
The absorbent article according to any one of <1> to <15>, wherein the nonwoven fabric used for the coating material is a spunbonded nonwoven fabric formed using a homopolymer polypropylene resin as a single resin.
<17>
The above-mentioned <1> to <16>, wherein the two non-stacking portions extend from the abdominal region to the dorsal region, and extend in a belt shape in parallel to the longitudinal direction, including the entire crotch region. The absorbent article according to any one of the above.
<18>
The absorbent article according to any one of <1> to <17>, wherein the covering material is formed of one sheet.
<19>
The longitudinal direction of the absorber, when looking at the main orientation direction of the constituent fibers of the coating material, coincides with the direction along the orientation direction of the fibers, and the lateral direction of the absorber is the orientation direction of the fibers. The absorbent article according to any one of the above <1> to <18>, which coincides with a direction orthogonal to a direction along the direction.

  Hereinafter, the present invention will be described more specifically with reference to Examples, but the present invention is not limited to such Examples.

[Example 1]
Kao Corporation, a diaper having the form shown in FIGS. 1 to 3, using an SMS nonwoven fabric having a basis weight of 10 g / m ² composed of fibers (2.0 dtex) made of a single resin, polypropylene resin, as a covering material. "Marys (registered trademark) Sarasara Air Through Small Size" was manufactured. Note that the ratio ((S1 / S0) × 100) of the area (S1 / S0) × 100 of the non-stacking portion to the area (S0) of the absorbent core is 8%, and the bonding portion to the area (S1) of the non-stacking portion. Was 30% ((S2 / S1) × 100). The joining portion was formed by applying pressure, and the pattern was formed into a dot-like pattern formed from a circle as shown in FIG.

[Example 2]
Example 2 was repeated in the same manner as in Example 1 except that the ratio ((S2 / S1) × 100) of the area (S2) of the joined portion to the area (S1) of the non-laid fiber portion was changed to 50%. Manufactured diapers.

[Comparative Example 1]
The same as in Example 1 except that the ratio ((S2 / S1) × 100) of the area (S2) of the joined portion to the area (S1) of the non-laid fiber portion was changed to 85%. Manufactured diapers.

[Comparative Example 2]
Comparative Example 2 was performed in the same manner as in Example 2 except that a nonwoven fabric composed of a core-sheath composite fiber (2.6 dtex, fiber length 51 mm) using polyethylene terephthalate for the core and polyethylene resin for the sheath was used. Manufactured diapers.

[Comparative Example 3]
A diaper of Comparative Example 3 was manufactured in the same manner as in Example 2 except that a mount made of tissue paper was used as a covering material, and a joint was formed by applying an adhesive.

(Performance evaluation)
For the diapers of Examples 1 and 2 and Comparative Examples 1 to 3, as described in the above <Measurement method of adhesive strength>, the bonding strength of the bonding portion when dry and the bonding strength of the bonding portion when wet were measured. did. The results are shown in Table 1 below. The softness of the diaper was evaluated according to the following method. The results are shown in Table 1 below. Hereinafter, a method for measuring the softness of the diaper will be described.

<Measurement conditions for diaper softness>
The evaluation environment was room temperature 20 ° C. and humidity 60% RH.
Ten mothers with infants using diapers For each diaper, the softness of the absorber was evaluated according to the following criteria. Table 1 shows the obtained results. When the evaluation of “good” according to the following criteria was 6 or more, the rating was “A”.

The evaluation of the softness of the absorber was represented by the following two grades.
Good: The absorber is soft and the diaper is soft.
Poor: There is a feeling of strangeness at the joint, and the absorber is hard.

  From the results shown in Table 1, it was found that the diapers of Examples 1 and 2 had higher bonding strengths at the dry and wet joints than the diapers of Comparative Examples 1 to 3, and the absorber was soft. . As described above, when the joining strength of the joining portion at the time of dry and wet is high, even if the absorbent absorbs the bodily fluid using the diapers of Examples 1 and 2, the inside of the absorbent is broken or the absorbent is divided. Therefore, it is assumed that the absorption performance of the absorber itself can be sufficiently exhibited. On the other hand, it was found that the diaper of Comparative Example 1 had high bonding strength at the dry and wet bonding portions, but the absorber was hard. Further, it was found that the diapers of Comparative Example 2 and Comparative Example 3 had a soft absorbent body, but had low bonding strength at the dry and wet bonded portions.

1 Expandable disposable diapers (absorbent articles)
2 Top sheet 3 Back sheet 4 Absorber 41 Absorbent core 42 Coating material 43 Non-stacking part 5 Leak-proof cuff 51 Elastic member for forming a leak-proof cuff 52 Sheet for forming a leak-proof cuff 53 Leg elastic member 54 Waist elastic member Reference Signs List 6 fastening tape 7 fastening area 8 joining part A abdominal area B back area C inseam area

Claims (3)

An absorbent body having an absorbent core containing an absorbent polymer and a covering material surrounding the absorbent core, the absorbent body having a longitudinal direction corresponding to the front-rear direction of the wearer and a lateral direction orthogonal thereto, and Absorbent article divided into a ventral region arranged on the ventral side, a dorsal region arranged on the back of the wearer, and a crotch region arranged between the ventral region and the dorsal region. So,
The coating material is composed of a nonwoven fabric including a layer formed of long fibers and fixed by a heat-sealing portion, and the long fibers are formed by uniformly spinning a thermoplastic resin made of a molten single resin. Is a single-layer fiber,
The nonwoven fabric constituting the coating material has a basis weight of 5 g / m ² or more and 20 g / m ² or less,
In the absorbent core, at least the crotch region, a non-stacking portion penetrating in the thickness direction extends in the vertical direction,
In the non-stacking portion, the covering material located on the skin-facing surface side of the absorbent core and the covering material located on the non-skin-facing surface side of the absorbent core are joined via a joining portion. Yes,
In plan view, the ratio of the area of the joining portion to the area of the non-stacking portion is 20% or more and 80% or less,
In plan view, the pattern of the joint, Ri dots, strip, or patterns der a combination thereof formed from circular or polygonal,
The absorbent article , wherein the joining portion is formed by pressing the covering material located on the skin facing surface side of the absorbent core and the covering material located on the non-skin facing surface side of the absorbent core .   2. The absorbent article according to claim 1, wherein the pattern of the joints is a pattern distributed and arranged in a vertical direction. The ratio of the joining strength of the joint when dry to the joining strength of the joint when wet is 80% or more,
3. The absorbent article according to claim 1, wherein the joining strength of the joining part when wet and the joining strength of the joining part when dry are 2.0 N / 30 mm or more, respectively.

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