JP7632989B2 - Tape-type disposable diapers - Google Patents

Description

The present invention relates to a tape-type disposable diaper with a connecting tape that improves fit.

There are three main types of disposable diapers: tape type, pants type, and pad type. Of these, tape type disposable diapers are worn by first placing them on the body in an unfolded state, and then connecting the connectors on both the left and right sides of the dorsal part to the outer surface of the abdominal part.

A typical tape-type disposable diaper has a crotch portion including the center in the front-to-rear direction, a ventral portion extending forward from the center in the front-to-rear direction, and a dorsal portion extending backward from the center in the front-to-rear direction, at least the dorsal portion has wing portions extending outward on both the left and right sides in the width direction beyond the crotch portion, the ventral portion and the dorsal portion have an intermediate portion located between the left and right wing portions, and the wing portions have connecting tapes that are detachably connected to the outer surface of the ventral portion. When in use, the wing portions are wrapped around the outer surface of the ventral portion from both sides of the waist, and the connecting tapes provided on the outer sides of the wing portions in the width direction are connected to the outer surface of the ventral portion. Such tape-type disposable diapers are used for infants and young children as well as for nursing care (for adults).

Conventionally, shapes of connecting tapes (also called "fastening tapes"; the same applies below) for tape-type disposable diapers are disclosed in the following Patent Documents 1 and 2. The fastening tape in Patent Document 1 comprises a fixing part that is fixed to the diaper and a fastening part that is connected to the fixing part, the fastening part has a stopper part, and the periphery of the fastening part is composed of a base edge that is located closest to the fixing part and crosses the fastening tape in its width direction, a tip edge that is located farthest from the fixing part and crosses the fastening tape in its width direction, and left and right side edges that are formed to approximately coincide with the left and right side edges of the fastening part, the width X of the tip edge being 15 to 40 mm, and the width Y of the base edge being 25 to 55 mm. m, the ratio X/Y of the width X to the width Y is 0.40 to 0.80, the fastening tape is made of a tape base material made of nonwoven fabric and a convex member of a mechanical fastener fixed onto the tape base material, the fastening portion is formed by the convex member, the fastening tapes are mirror images of each other, and when multiple pieces of one fastening tape are arranged so that the left and right side edges of the fixing portion are connected, part of the outline formed by them matches the outline of the fastening portion of the other fastening tape. The fastening tape described in Patent Document 1 is shown in Figure 7 (b).

On the other hand, the fastening tape described in Patent Document 2 comprises a base sheet connected to side flaps, and a hook sheet fixed to the base sheet, the base sheet having a plurality of engaging members that engage with the front waist region, the base sheet having a joint joined to the side flaps and a tip extending outward in the product width direction beyond the hook sheet, the length of the tip in the product width direction is 5 to 12 mm, the distance in the product longitudinal direction between the outer end of the joint and the outer end of the hook sheet in the product longitudinal direction is 2 to 12 mm, the length in the product longitudinal direction at the boundary between the hook sheet and the tip is at least twice the distance in the product longitudinal direction between the inner end of the base sheet in the product longitudinal direction and the inner end of the hook sheet in the product longitudinal direction, and the hook sheet extends outward in the product longitudinal direction beyond the midpoint between the outer end of the hook sheet in the product longitudinal direction at the inner end of the hook sheet in the product width direction and the outer end of the tip in the product longitudinal direction at the inner end of the tip in the product width direction.

Patent No. 4014267 Patent No. 5291234

In the fastening tape described in Patent Document 1, the length of the hook material in the front-rear direction varies greatly in the widthwise intermediate region of the fastening tape. That is, in the widthwise intermediate region, the fastening tape has a curved shape from the base end side to the tip side, and tapers toward the tip. This reduces the peel strength between the fastening tape and the outer ventral surface of the disposable diaper. This reduction in peel strength is particularly noticeable in the widthwise intermediate region. If the peel strength in the widthwise intermediate region is low, the fastening tape will peel off easily even if the peel strength in other regions is high, which creates a problem in that consumers feel uneasy when putting on and taking off the fastening tape, worrying that it will peel off easily.

The fastening tape described in Patent Document 2 has a large area in the widthwise middle region, so it does not have the problems described in Patent Document 1. However, because it does not have a symmetrical (mirror image) shape like Patent Document 1, there is a problem that cut pieces of the fastening tape end up as waste when manufacturing diapers.

Other fastening tapes are available in a long, narrow rectangular shape, but if the length of the fastening tape in the front-to-rear direction is short in the portion from the inner edge of the hook sheet fixed to the fastening tape in the width direction to the fixed edge of the fastening tape, this portion of the fastening tape is likely to become twisted in the front-to-rear direction when the wearer of the disposable diaper moves his or her legs.

The primary objective of the present invention is to provide a tape-type disposable diaper with a connecting tape that has high peel strength and excellent fit. A secondary objective of the present invention is to provide a tape-type disposable diaper in which the fastening tape is less likely to twist in the front-to-rear direction when worn, and in which the back of the diaper is less likely to shift in the front-to-rear direction.

Various aspects of tape-type disposable diapers that solve the above problems are as follows.
<First aspect>
A crotch portion having both side edges extending from a middle of the ventral portion in the front-to-rear direction to a middle of the dorsal portion in the front-to-rear direction, and a ventral portion extending forward from a middle of the ventral portion in the front-to-rear direction, and a crotch portion having both side edges extending from a middle of the ventral portion in the front-to-rear direction to a middle of the dorsal portion in the front-to-rear direction,
An absorbent body incorporated in an area including the crotch area;
Wing portions extending outward in a width direction beyond the crotch portion on the ventral portion and the dorsal portion;
The back portion has connecting tapes on both sides thereof for detachably connecting to the ventral portion.
In tape-type disposable diapers,
The connecting tape has a base end portion fixed to the wing portion and an extension portion extending outward in a width direction from the base end portion,
The shape of the extension portion of the connecting tape is such that the length in the front-rear direction narrows in a stepped manner from the base end side to the tip end side,
The length of the extension portion in the front-rear direction at the widthwise intermediate portion is 15 mm to 45 mm,
The length in the front-rear direction of the widthwise intermediate portion of the extension portion is the same at any point in the widthwise direction, or the length varies depending on any point in the widthwise direction, and the difference between the longest part and the shortest part is within a range of 2.0 mm;
A tape-type disposable diaper, characterized in that a connecting portion for fixing the connecting tape to an outer surface of the abdominal portion is provided at least in a widthwise intermediate portion of the connecting tape.

(Action and Effect)
By setting the front-rear length of the widthwise intermediate portion of the extension portion within a range of 15 mm to 45 mm, the front-rear length of the widthwise intermediate portion of the extension portion being the same length at any point in the width direction or varying in length at any point in the width direction, and setting the difference between the longest and shortest portions within a range of 2.0 mm, it is possible to increase the peel strength compared to the case in which the widthwise intermediate portion is greatly curved as in Patent Document 1. In other words, by setting the difference between the longest and shortest portions within a range of 2.0 mm, the peel strength is approximately 160 gf to 180 gf, so that consumers are less likely to feel uneasy about the peel strength (uneasy about whether the connecting tape is securely fixed to the ventral outer surface).

<Second aspect>
The tape-type disposable diaper according to the first aspect, wherein the length of the base portion of the extension portion in the front-to-rear direction is within the range of approximately 63% to 70% of the length of the base end portion in the front-to-rear direction.

(Action and Effect)
By setting the length of the base portion of the extension portion in the front-to-rear direction as described above, the base portion of the extension portion becomes thicker (the length in the front-to-rear direction becomes longer), so that it is possible to prevent the base portion of the extension portion from twisting. Specifically, when the length of the base end portion in the front-to-rear direction is set to 50 mm to 75 mm, it is preferable that the length of the base portion in the front-to-rear direction is set to 30 mm to 48 mm.

<Third aspect>
The edge of one side in the front-rear direction of the connecting tape has a shape in which concave curves and convex curves are alternately arranged from the base end side to the tip end side,
In the tape-type disposable diaper according to the first aspect, the connecting portion is disposed between a concave curve and a convex curve provided at both ends of the widthwise intermediate portion of the connecting tape.

(Action and Effect)
Since the connecting portion is contained between the concave curve and the convex curve provided at both ends of the width direction middle part of the connecting tape, when the wearer's foot comes into contact with the base part of the extension part, the base part is easily rolled up. Also, since there is no connecting portion at the base part, discomfort is reduced when the base part comes into contact with the foot.

The present invention provides a tape-type disposable diaper with high peel strength of the connecting tape and excellent fit. It also provides a tape-type disposable diaper in which the fastening tape is less likely to twist in the front-to-back direction when worn, and the back of the diaper is less likely to shift in the front-to-back direction.

FIG. 2 is a plan view showing the inner surface of the tape-type disposable diaper in an unfolded state. FIG. 2 is a plan view showing the outer surface of the tape-type disposable diaper in an unfolded state. This is a cross-sectional view taken along line 6-6 in Figure 1. This is a cross-sectional view taken along line 7-7 in Figure 1. 1A is a cross-sectional view taken along line 8-8 in FIG. 1, and FIG. This is a cross-sectional view taken along line 5-5 in Figure 1. 1A and 1B are plan views of a connecting tape according to the present invention and a conventional example, respectively. 1A to 1C are plan views showing a manufacturing process of the connecting tape.

Figures 1 to 6 show an example of a tape-type disposable diaper, where the symbol X in the figure indicates the overall width of the diaper excluding the connecting tape, and the symbol L indicates the overall length of the diaper. The hot melt adhesive can be applied by known methods such as slot application, continuous line or dotted line bead application, spiral or Z-shaped spray application, or pattern coating (transfer of hot melt adhesive using a letterpress method). Alternatively or in addition to this, at the fixing portion of the elastic member, the hot melt adhesive can be applied to the outer surface of the elastic member to fix the elastic member to the adjacent member. As the hot melt adhesive, for example, EVA-based, adhesive rubber-based (elastomer-based), olefin-based, polyester/polyamide-based, and other types are available, but there are no particular limitations on the types that can be used. As a joining means for joining each component, material welding means such as heat sealing and ultrasonic sealing can also be used.

This tape-type disposable diaper has a ventral portion F extending forward from the center in the front-to-rear direction LD, and a dorsal portion B extending rearward from the center in the front-to-rear direction LD. This tape-type disposable diaper also has an absorbent body 56 built into an area including the crotch area, a liquid-permeable top sheet 30 covering the front side of the absorbent body 56, a liquid-impermeable sheet 11 covering the back side of the absorbent body 56, and an exterior nonwoven fabric 12 covering the back side of the liquid-impermeable sheet 11 and constituting the outer surface of the product.

The materials and features of each part will be explained below in order.
(Absorbent)
The absorbent body 56 is a part that absorbs and retains excreted liquid, and can be formed by a fiber assembly. As the fiber assembly, in addition to stacked staple fibers such as cotton-like pulp and synthetic fibers, a filament assembly obtained by opening a tow (fiber bundle) of synthetic fibers such as cellulose acetate as necessary can be used. The fiber basis weight can be, for example, about 100 to 300 g/m ² when stacking cotton-like pulp or staple fibers, and can be, for example, about 30 to 120 g/m ² when the filament assembly is used. The fineness of the synthetic fibers is, for example, 1 to 16 dtex, preferably 1 to 10 dtex, and more preferably 1 to 5 dtex. In the case of a filament assembly, the filaments may be non-crimped fibers, but are preferably crimped fibers. The degree of crimp of the crimped fiber can be, for example, about 5 to 75 pieces per 2.54 cm, preferably about 10 to 50 pieces, and more preferably about 15 to 50 pieces. Furthermore, uniformly crimped fibers can be used.

(Superabsorbent polymer particles)
The absorbent body 56 may contain superabsorbent polymer particles in part or in whole. The superabsorbent polymer particles include not only "particles" but also "powder". As the superabsorbent polymer particles, those used in this type of absorbent article may be used as they are. The particle size of the superabsorbent polymer particles is not particularly limited, but it is preferable that, for example, when sieving (shaking for 5 minutes) using a 500 μm standard sieve (JIS Z8801-1:2006) and sieving (shaking for 5 minutes) using a 180 μm standard sieve (JIS Z8801-1:2006) for the particles that fall below the sieve, the ratio of particles remaining on the 500 μm standard sieve is 30% by weight or less and the ratio of particles remaining on the 180 μm standard sieve is 60% by weight or more.

There are no particular limitations on the material that can be used for the superabsorbent polymer particles, but those with a water absorption capacity of 40 g/g or more are preferred. Superabsorbent polymer particles include starch-based, cellulose-based and synthetic polymer-based materials, and examples of materials that can be used include starch-acrylic acid (salt) graft copolymers, saponified starch-acrylonitrile copolymers, crosslinked products of sodium carboxymethylcellulose and acrylic acid (salt) polymers. The shape of the superabsorbent polymer particles is preferably the commonly used powder-like form, but other shapes can also be used.

The highly absorbent polymer particles preferably have a water absorption speed of 70 seconds or less, and particularly 40 seconds or less. If the water absorption speed is too slow, the liquid supplied to the absorbent body 56 tends to flow back out of the absorbent body 56, which is known as backflow.

The highly absorbent polymer particles preferably have a gel strength of 1000 Pa or more. This effectively prevents the sticky feeling after absorbing liquid, even when the absorbent body 56 is bulky.

The basis weight of the highly absorbent polymer particles can be appropriately determined depending on the absorption amount required for the application of the absorbent body 56. Therefore, although it cannot be generally stated, it can be set to 50 to 350 g/ ^m2 . If the basis weight of the polymer is less than 50 g/ ^m2 , it becomes difficult to ensure the absorption amount. If it exceeds 350 g/ ^m2 , not only will the effect be saturated, but the excess of highly absorbent polymer particles will cause an uncomfortable gritty feeling.

(packaging sheet)
In order to prevent the superabsorbent polymer particles from escaping or to improve the shape retention of the absorbent body 56, the absorbent body 56 can be incorporated as an absorbent element 50 wrapped in a wrapping sheet 58. As the wrapping sheet 58, tissue paper, particularly crepe paper, nonwoven fabric, polylaminated nonwoven fabric, a sheet with small holes, etc. can be used. However, it is preferable that the sheet is one from which the superabsorbent polymer particles do not escape. When using nonwoven fabric instead of crepe paper, hydrophilic SMMS (spunbond/meltblown/meltblown/spunbond) nonwoven fabric is particularly suitable, and polypropylene, polyethylene/polypropylene, etc. can be used as the material. The fiber basis weight is preferably 5 to 40 g/m ² , particularly 10 to 30 g/m ² .

As shown in FIG. 3, this packaging sheet 58 may be structured so that one sheet wraps the entire absorbent body 56, or multiple sheets (e.g., two sheets above and two sheets below) may wrap the entire absorbent body 56. The packaging sheet 58 may also be omitted.

(Top sheet)
The top sheet 30 is liquid permeable, and may be, for example, a nonwoven fabric with or without holes, a porous plastic sheet, or the like. The raw fiber of the nonwoven fabric is not particularly limited. Examples of the raw fiber include synthetic fibers such as olefins such as polyethylene and polypropylene, polyesters, and polyamides, regenerated fibers such as rayon and cupra, natural fibers such as cotton, and mixed fibers and composite fibers using two or more of these. Furthermore, the nonwoven fabric may be manufactured by any processing. Examples of the processing method include known methods such as the spunlace method, the spunbond method, the thermal bond method, the meltblown method, the needle punch method, the air-through method, and the point bond method. For example, if flexibility and drape are required, the spunlace method is a preferred processing method, and if bulkiness and softness are required, the thermal bond method is a preferred processing method.

The top sheet 30 extends from the front end to the rear end of the product in the front-to-rear direction, and extends laterally beyond the absorbent body 56 in the width direction WD. However, appropriate modifications can be made as necessary, such as making the width of the top sheet 30 shorter than the overall width of the absorbent body 56, for example, when the starting point of the rising gathers 60 described below is located closer to the center in the width direction than the side edges of the absorbent body 56.

(middle seat)
In order to quickly transfer liquid that has permeated the top sheet 30 to the absorbent body, an intermediate sheet (also called a "second sheet") 40 that has a faster liquid permeability rate than the top sheet 30 can be provided. This intermediate sheet 40 is intended to quickly transfer liquid to the absorbent body, improve the absorption performance of the absorbent body, and prevent the "backflow" phenomenon of absorbed liquid from the absorbent body. The intermediate sheet 40 can also be omitted.

Examples of the intermediate sheet 40 include the same material as the top sheet 30, spunlace nonwoven fabric, spunbond nonwoven fabric, SMS nonwoven fabric, pulp nonwoven fabric, mixed sheet of pulp and rayon, point-bond nonwoven fabric, and crepe paper. In particular, air-through nonwoven fabric is preferred because it is bulky. For the air-through nonwoven fabric, it is preferred to use composite fibers with a core-sheath structure, and in this case, the resin used for the core may be polypropylene (PP), but polyester (PET) with high rigidity is preferred. The basis weight is preferably 17 to 80 g/m ² , and more preferably 25 to 60 g/m ^2. The thickness of the raw fiber of the nonwoven fabric is preferably 2.0 to 10 dtex. In order to make the nonwoven fabric bulky, it is also preferred to use eccentric fibers with no core in the center, hollow fibers, or eccentric and hollow fibers as the mixed fibers of all or part of the raw fiber.

In the illustrated example, the intermediate sheet 40 is shorter than the width of the absorbent body 56 and is positioned in the center, but it may be provided across the entire width. The intermediate sheet 40 may also be provided across the entire length of the diaper, or it may be provided only in the middle part including the excretion position as in the illustrated example.

(Liquid-impermeable sheet)
The liquid-impermeable sheet 11 is not particularly limited, but is preferably moisture-permeable. For example, a microporous sheet obtained by kneading an inorganic filler into an olefin resin such as polyethylene or polypropylene to form a sheet and then stretching the sheet in a uniaxial or biaxial direction can be suitably used as the liquid-impermeable sheet 11. In addition, a sheet having improved waterproofness using a nonwoven fabric as a base material can also be used as the liquid-impermeable sheet 11.

It is desirable for the liquid-impermeable sheet 11 to extend over the same or a wider area as the absorbent body 56 in the front-rear direction LD and width direction WD, but if necessary, for example, when other water-blocking means are present, it may be structured so that it does not cover the ends of the absorbent body 56 in the front-rear direction LD and width direction WD.

(Outer nonwoven fabric)
The exterior nonwoven fabric 12 covers the entire back side of the liquid-impermeable sheet 11, giving the outer surface of the product a cloth-like appearance. The exterior nonwoven fabric 12 is not particularly limited, and examples of the material fiber include synthetic fibers such as olefins, polyesters, and polyamides, such as polyethylene or polypropylene, as well as regenerated fibers such as rayon and cupra, and natural fibers such as cotton. Examples of the processing method include spunlace, spunbond, thermal bond, air-through, and needle punch. However, long fiber nonwoven fabrics such as spunbond nonwoven fabrics, SMS nonwoven fabrics, and SMMS nonwoven fabrics are preferred in terms of achieving both texture and strength. The nonwoven fabric can be used in a single layer or in a stack of multiple layers. In the latter case, it is preferable to bond the nonwoven fabrics together with a hot melt adhesive or the like. When using a nonwoven fabric, the fiber weight is preferably 10 to 50 g/m ² , and more preferably 15 to 30 g/m ² .

(Rising gather)
In order to prevent excrement from moving laterally along the top sheet 30 and to prevent so-called lateral leakage, it is preferable that rising gathers 60 that rise towards the wearer's skin are provided on both sides in the width direction WD of the front surface. Of course, the rising gathers 60 can be omitted.

When rise-up gathers 60 are used, their structure is not particularly limited, and any known structure can be used. The rise-up gathers 60 in the illustrated example are composed of a gather sheet 62 that is substantially continuous in the width direction WD, and an elongated gather elastic member 63 that is fixed to the gather sheet 62 in a stretched state along the front-to-back direction LD. A water-repellent nonwoven fabric can be used as the gather sheet 62, and rubber thread or the like can be used as the gather elastic member 63. As shown in Figures 1 and 2, multiple elastic members can be provided, or one elastic member can be provided.

The inner surface of the gathered sheet 62 has a joining start point in the width direction WD on the side of the top sheet 30, and the portion extending from this joining start point to the outside in the width direction is joined with a hot melt adhesive or the like to the inner surface of each side flap portion SF, that is, in the illustrated example, to the side of the liquid-impermeable sheet 11 and the side of the exterior nonwoven fabric 12 located on the outside in the width direction.

Around the legs, the inside of the joining start point of the rising gathers 60 in the width direction is fixed to the top sheet 30 at both ends in the front-to-back direction of the product, but the area between them is an unfixed free area, which rises due to the contraction force of the elastic member 63 and comes into close contact with the body surface.

(End flap section, side flap section)
The illustrated tape-type disposable diaper has a pair of end flap portions EF that do not have the absorbent body 56 and extend to the front and rear sides of the absorbent body 56, respectively, and a pair of side flap portions SF that do not have the absorbent body 56 and extend laterally beyond both side edges of the absorbent body 56. The side flap portions SF may be made of a material (such as the exterior nonwoven fabric 12) that is continuous with the portion that has the absorbent body 56, as in the illustrated example, or may be formed by attaching another material.

(Flat gather)
A side elastic member 64 made of an elongated elastic member such as rubber thread is fixed to each side flap portion SF in a stretched state in the front-to-rear direction LD, whereby the leg portion of each side flap portion SF is configured as flat gathers. As shown in the illustrated example, the leg elastic member 64 is provided between the gathered sheet 62 and the liquid-impermeable sheet 11 on the widthwise outer side near the joining start end of the joining portion of the gathered sheet 62, and can also be provided between the liquid-impermeable sheet 11 and the exterior nonwoven fabric 12 in the side flap portion SF. The leg elastic member 64 can be provided in multiple pieces on each side as shown in the illustrated example, or only one piece on each side.

The flat gathers are the areas where the contraction force of the side elastic members 64 acts (the areas where the side elastic members 64 are shown in the figure). Therefore, in addition to the form in which the side elastic members 64 are present only in the areas of the flat gathers, the side elastic members 64 are present on the front side, back side, or both sides of the flat gathers, but the side elastic members are cut into small pieces in one or multiple places outside the areas of the flat gathers, are not fixed to the sheets that sandwich the side elastic members 64, or both, so that the contraction force does not act on areas other than the flat gathers (essentially equivalent to no elastic members being provided), and the contraction force of the side elastic members 64 acts only on the areas of the flat gathers.

(Connecting tape)
The side flap portions SF of the dorsal portion B are each provided with a connecting tape 13 which is detachably connected to the outer surface of the abdominal portion F. When putting on the disposable diaper 10, the connecting tape 13 is wrapped around the outer surface of the abdominal portion F from both sides of the waist, and the connecting portions 13A of the connecting tape 13 are connected to appropriate locations on the outer surface of the abdominal portion F.

The structure of the connecting tape 13 is not particularly limited, but in the illustrated example, it has a base end 13C fixed to the side flap portion SF, and an extension portion 13B extending outward in the width direction WD from the base end 13C. The extension portion 13B has a connecting portion 13A that connects to the sheet base material and the ventral outer surface provided in the middle of the sheet base material in the width direction, and the tip side of the connecting portion 13A is a gripping portion 13D.

The widthwise middle portion N of the connecting tape 13 refers to the range between point S-S, which is 5 mm away from the widthwise middle point T-T of the connecting portion 13A, and point U-U, which is 5 mm away from the base end. In other words, the widthwise middle portion N of the connecting portion 13A is the portion between S-S and U-U, and its length in the width direction WD is 1 cm.

In the embodiment of FIG. 7(a), the length of the connecting tape 13 in the front-rear direction LD is gradually narrowed in a stepped manner from the base end 13C toward the tip end. The stepped shape means that the front-rear edge of the connecting tape 13 is not narrowed in a gentle curve as in Prior Art Document 2, but narrows in multiple steps like a staircase. In the embodiment of FIG. 7(a), the extension portion 13C has three steps, but it may have two or four or more steps. The difference in the front-rear length between adjacent steps is preferably about 5 mm to 10 mm.

The length Q of the connecting tape 13 in the front-rear direction LD is the same in the widthwise intermediate portion N of the connecting tape 13. The length Q of the connecting tape 13 in the front-rear direction LD of the connecting tape 13 in the widthwise intermediate portion N is preferably 15 mm to 45 mm, more preferably 20 mm to 40 mm, and even more preferably 25 mm to 37.5 mm. The length Q of the connecting tape 13 in the front-rear direction LD of the connecting tape 13 in the widthwise intermediate portion N is preferably 55% to 95% of the length P of the base portion 13E of the extension portion 13B in the front-rear direction LD (the length of the portion where the outer edge of the side flap portion SF in the width direction WD and the connecting tape 13 overlap. The same applies below.), more preferably 60% to 90%, and even more preferably 70% to 80%. The length Q of the connecting tape 13 in the front-rear direction LD of the connecting tape 13 in the widthwise intermediate portion N is preferably half the length O of the base end portion in the front-rear direction. The present invention is not limited to this form, and may be, for example, a form in which the length of the tip S-S of the widthwise intermediate portion N is shorter than the length of the base end U-U. However, if the length of the tip S-S is too short compared to the length of the base end U-U, the peel strength will be weakened as in Patent Document 1. Therefore, if the length of the base end U-U is 100%, it is preferable to set the length of the tip S-S to about 90% to 100%. Specifically, when the length of the base end U-U is 25 mm to 26 mm, it is preferable to set the length of the tip S-S to 24 to 25 mm, and when the length of the base end U-U is 37.5 mm to 39 mm, it is preferable to set the length of the tip S-S to 36 to 37.5 mm. In order to prevent the peel strength from decreasing to the extent that it makes consumers uneasy, it is preferable to set the difference in length between the base end U-U and the tip S-S (length difference) to within 2 mm.

It is preferable that the length P in the front-to-rear direction LD of the root portion 13E of the extension portion 13B is about 63% to 70% of the length O in the front-to-rear direction of the base end portion. By making the length P in the front-to-rear direction LD of the root portion 13E of the extension portion 13B 63% or more, the length of the root portion 13E becomes sufficiently long, and it is possible to prevent the occurrence of twisting of the nonwoven fabric that is likely to occur in the side flap portion SF when worn. In addition, by making the length P in the front-to-rear direction LD of the root portion 13E of the extension portion 13B 70% or less, as shown in FIG. 8, when the left and right connecting tapes 13, 13 are manufactured to have the same shape (mirror image), the front-to-rear length of the gripping portion 13D can be secured to be at least about 30% of the front-to-rear direction length O of the base end portion 13C, which has the effect of preventing the ease of gripping of the connecting tape 13 from being deteriorated. Specifically, it is preferable that the length P in the front-to-rear direction LD of the root portion 13E of the extension portion 13B is 30 mm to 48 mm, and the length O in the front-to-rear direction of the base end portion 13C is 50 mm to 75 mm. It is preferable that the difference (difference in length) between the length P in the front-to-rear direction LD of the root portion 13E of the extension portion 13B and the length O in the front-to-rear direction of the base end portion 13C is within 20 mm. In general, it is preferable that the length in the front-to-rear direction of the grip portion 13D is about 50% to 70% of the length Q in the front-to-rear direction LD of the width direction middle portion N of the connecting tape 13. Specifically, it is preferable that the length in the front-to-rear direction of the grip portion 13D is about 10 mm to 27 mm.

By setting the length P in the front-to-rear direction LD of the root portion 13E of the extension portion 13B and the length Q in the front-to-rear direction LD of the widthwise middle portion N of the connecting tape 13 to the above lengths, the thickness of the extension portion 13B between the root portion 13E of the extension portion 13B and the widthwise middle portion N of the connecting tape 13 can be increased. This makes it possible to prevent twisting from occurring between the root portion 13E of the extension portion 13B and the widthwise middle portion N of the connecting tape 13.

7(a), the length in the width direction WD of the base end 13C is preferably 15 mm to 25 mm, the length in the width direction WD of the root portion 13E is preferably 10 mm to 15 mm, the length in the width direction WD of the connecting portion 13A is preferably 18 mm to 24 mm, and the length in the width direction WD of the knob portion 13D is preferably 10 mm to 15 mm.

In the embodiment of FIG. 7(a), six curved portions R1 to R6 are formed on one side of the connecting tape 13 in the front-rear direction from the base end side to the tip end side. R1, R3, and R5 are concave curves toward the center side of the connecting tape 13 in the front-rear direction, and R2, R4, and R6 are convex curves toward the outside of the connecting tape 13 in the front-rear direction. The extension portion 13B extends in three stages, broadly divided into R1 to R2, R3 to R4, and R5 to R6, and is characterized in that the second stage R3 to R4 is an almost flat section. By using such many curved sections as the shape of the connecting tape 13, it becomes softer, more pleasant to the touch, and less likely to peel off compared to when the corresponding parts are made acute-angled. In addition, by making the second stage an almost flat section, the connecting force (also called adhesion force) of the connecting portion 13A to the ventral outer surface can be increased compared to the prior example shown in FIG. 7(b).

To more preferably modify the embodiment of FIG. 7(a), it is preferable to make the length of connecting portion 13A in the width direction WD shorter than the length of R3 to R4, and to place connecting portion 13A between R3 and R4. In this configuration, when the wearer's foot comes into contact with base portion 13E of the connecting tape, i.e., peripheral portion M of R2, the convex portion of R2 is more likely to fold back because there is no connecting portion 13A in peripheral portion M. This has the advantage that connecting portion 13A is less likely to come into contact with the foot.

As mentioned above, if the length in the front-to-rear direction at the widthwise intermediate portion N of the connecting tape 13 from the tip end S-S to the base end U-U is made constant and the same length, the two straight lines connecting the tip ends S, S and the base ends U, U will be straight and parallel. And, if such a connecting tape 13 is attached in parallel to the front target tape provided on the outer surface of the ventral side, there is an advantage that the tape is less likely to slip even if the wearer (especially the baby) moves.

The connecting portion 13A may be provided with a hook material (male material) of a mechanical fastener (hook-and-loop fastener) or with an adhesive layer. The hook material has a number of engaging protrusions on its connecting surface, and the shapes of the engaging protrusions include (A) a L-shape, (B) a J-shape, (C) a mushroom shape, (D) a T-shape, and (E) a double J-shape (a shape in which two J-shapes are joined back-to-back), but any shape is acceptable.

The sheet base material forming the base end portion 13C to the extension portion 13B may be a nonwoven fabric, a plastic film, a polylaminated nonwoven fabric, paper, or a composite material thereof, but a spunbond nonwoven fabric, an air-through nonwoven fabric, or a spunlace nonwoven fabric having a fineness of 1.0 to 3.5 dtex, a basis weight of 20 to 100 g/ ^m2 , and a thickness of 1 mm or less is preferred.

The shape of the connecting tapes 13 provided on the left and right sides of the side flap portion SF is preferably such that when the connecting tapes 13 are rotated 180 degrees and arranged alternately as shown in Figure 8, the side edges of the connecting tapes 13 match each other, i.e., they form mirror images. By using such a shape, no cutting pieces are produced when the connecting tapes 13 are manufactured, making it easier to keep the manufacturing site clean and improving manufacturing efficiency.

(Target sheet)
It is preferable to provide a target portion at the connection portion of the connecting tape 13 in the abdominal part F. The target portion can be provided by attaching a target sheet 20 for facilitating connection to the outer surface of the abdominal part F, as in the illustrated example. When the connecting portion 13A is made of a hook material, the target sheet 20 can be provided on the surface of a sheet base material made of a plastic film or nonwoven fabric, on which a large number of loop threads are provided so that the engaging protrusions of the hook material can be entangled. In the case of an adhesive layer, the target sheet 20 can be provided on the surface of a sheet base material made of a smooth plastic film that is highly adhesive, on which a peeling treatment has been applied. In addition, when the connecting portion of the connecting tape 13 in the abdominal part F is made of a nonwoven fabric, for example, when the outer nonwoven fabric 12 is provided as in the illustrated example, the target sheet 20 can be omitted, and the hook material can be entangled with the fibers of the outer nonwoven fabric 12 to connect the connecting portions. In this case, the target sheet 20 as a marker can be provided between the outer nonwoven fabric 12 and the liquid-impermeable sheet 11, and a marker can be printed on the outer surface of the outer nonwoven fabric 12 or the liquid-impermeable sheet 11.

(Wing part)
As shown in Figs. 1 and 2, the present tape-type disposable diaper has a crotch portion M extending from the middle of the ventral portion F in the front-rear direction LD to the middle of the back portion B in the front-rear direction LD. The ventral portion F and the back portion B have wing portions WP extending outward in the width direction WD beyond the crotch portion M. The lower edge 70 of the wing portion of the ventral portion F extends from the front end of the side edge of the crotch portion M toward the front so as to be positioned obliquely outward, and the lower edge 75 of the wing portion of the back portion B extends from the rear end of the side edge of the crotch portion M toward the rear so as to be positioned obliquely outward. In the illustrated example, the side edges of the wing portions WP are linear, but are not limited to this and other known shapes may be adopted. The dimension of the crotch portion M in the front-rear direction LD can be determined as appropriate, but may be about 1.2 to 1.4 times the minimum width M _X of the crotch portion M. In the case of use for infants, the dimension M _Y of the crotch area M in the front-to-rear direction LD is about 10 to 30 cm.

(Experimental Example)
7, (a) is the tape according to the present invention, and (b) is the tape described in Patent Document 1. Using these two types of tapes, a peel strength test was carried out as follows.

First, tape-type disposable diapers equipped with the connecting tapes (a) and (b) were prepared, and only the front target portion was cut and removed from each diaper. Then, each diaper was attached to the mounting table of a tensile tester (Shimadzu Corporation, model number AG-X500N). Next, the connecting tape was attached to the outer surface of the front body in the same manner as when the diaper was worn, and a load was applied to the connecting tape. This load was applied by using a 2 kg roller to move back and forth over the connecting tape. After that, the connecting tape was peeled off in a 90-degree direction at a speed of 300 mm/min using the tensile tester.

The experimental results are shown in Table 1.

It can be seen that the peel strength of the widthwise intermediate portion of the connecting tape is higher in the shape of FIG. 7(a) than in the shape of FIG. 7(b). In particular, in FIG. 7(a), the peel strength of the widthwise intermediate portion of the connecting tape is 179 gf, and the maximum convex point is 301 gf, resulting in a difference of 122 gf. In contrast, in FIG. 7(b), the peel strength of the widthwise intermediate portion of the connecting tape is 124 gf, and the maximum convex point is 283 gf, resulting in a difference of 159 gf. In other words, the difference is smaller in FIG. 7(a), so the wearer can feel that the connecting tape is firmly fixed when peeling it off. Also, in the shape of FIG. 7(b), the peel strength of the widthwise intermediate portion of the connecting tape is a low value of 124 gf, which has the disadvantage that it peels off easily.

<Explanation of terms used in the specification>
As used herein, the following terms have the following meanings unless otherwise specified in the specification.
The "front-to-back direction" refers to the direction indicated by the symbol LD in the figure (vertical direction), and the "width direction" refers to the direction indicated by the symbol WD in the figure (left-to-right direction), with the front-to-back direction and the width direction being perpendicular to each other.

- "Curve" does not include straight lines.

- "Expanded state" means a flat, unfolded state without contraction or sagging.

"Elongation rate" refers to the value when the natural length is 100%. For example, an elongation rate of 200% is synonymous with an elongation ratio of 2 times.

・"Basis weight" is measured as follows. After pre-drying the sample or test piece, leave it in a test room or device under standard conditions (test location: temperature 23±1°C, relative humidity 50±2%) until it reaches a constant weight. Pre-drying refers to bringing the sample or test piece to a constant weight in an environment at a temperature of 100°C. Note that pre-drying is not necessary for fibers with an official moisture regain of 0.0%. Using a sample collection template (100mm x 100mm), cut out a sample measuring 100mm x 100mm from the test piece that has reached a constant weight. Measure the weight of the sample and multiply it by 100 to calculate the weight per square meter, which is the basis weight.

"Thickness" is automatically measured using an automatic thickness measuring device (KES-G5 handy compression tester) under the conditions of a load of 0.098 N/cm ² and a pressurized area of 2 cm ² .

- "Water absorption" is measured according to JIS K7223-1996 "Test method for water absorption of superabsorbent resins."

The "absorption rate" is the "time to the end point" when 2 g of superabsorbent polymer and 50 g of saline are used to perform the "test method for the absorption rate of superabsorbent polymers" according to JIS K7224-1996.

-If no specification is given regarding the environmental conditions for a test or measurement, the test or measurement shall be performed in a test room or equipment under standard conditions (the test location shall be a temperature of 23±1°C and a relative humidity of 50±2%).

- Unless otherwise specified, the dimensions of each part refer to the dimensions in the unfolded state, not the natural length.

The present invention can be applied to tape-type disposable diapers such as those in the above example.

11...Liquid-impermeable sheet, 12...External nonwoven fabric, 13...Connecting tape, 13A...Connecting portion, 13B...Extending portion, 13C...Base end portion, 13D...Pinch portion, 13E...Root portion, 20...Target sheet, 30...Top sheet, 40...Middle sheet, 50...Absorbent element, 56...Absorbent body, 58...Wrapping sheet, 60...Rising gathers, 62...Gathered sheet, 64...Side elastic member, B...Back portion, F...Belly portion, LD...Front-rear direction, M...Crotch portion, SF...Side flap portion, WD...Width direction, WP...Wing portion

Claims (3)

A crotch portion having both side edges extending from a midpoint of the ventral portion to a midpoint of the dorsal portion in the front-rear direction, the ventral portion extending forward from a midpoint of the ventral portion in the front-rear direction, and the dorsal portion extending backward from the midpoint of the ventral portion in the front-rear direction,
An absorbent body incorporated in an area including the crotch area;
Wing portions extending outward in a width direction beyond the crotch portion on the ventral portion and the dorsal portion;
The back portion has connecting tapes on both sides thereof for detachably connecting to the ventral portion.
In tape-type disposable diapers,
The connecting tape has a base end portion fixed to the wing portion and an extension portion extending outward in a width direction from the base end portion,
The shape of the extension portion of the connecting tape is such that the length in the front-rear direction narrows in a stepped manner from the base end side to the tip end side,
The length of the extension portion in the front-rear direction at the widthwise intermediate portion is 15 mm to 45 mm,
The length in the front-rear direction of the widthwise intermediate portion of the extension portion is the same at any point in the widthwise direction, or the length varies depending on any point in the widthwise direction, and the difference between the longest part and the shortest part is within a range of 2.0 mm;
A connecting portion for fixing the connecting tape to an outer surface of the abdominal portion is provided at least in a width direction intermediate portion of the extending portion of the connecting tape,
The connecting portion is not provided at a base portion of the extending portion of the connecting tape that is closer to the base end of the extending portion in the width direction than a middle portion of the extending portion in the width direction,
The width direction intermediate portion of the extending portion of the connecting tape is a range between a point 5 mm away from the tip end side and a point 5 mm away from the base end side based on the width direction intermediate point of the connecting portion,
The connecting tape has a protruding portion at the base portion that faces outward in the front-rear direction,
The connecting portion is not provided on the protruding portion,
The connecting portion is a hook member of a mechanical fastener,
The connecting portion is not provided on the base end side from the convex portion.
A tape-type disposable diaper characterized by: The tape-type disposable diaper according to claim 1, wherein a gripping portion for gripping the connecting tape is provided on the widthwise tip side of the extending portion of the connecting tape, rather than on the widthwise middle portion of the extending portion of the connecting tape, a part of the extending portion is the gripping portion, and the connecting portion is not provided on the gripping portion. Both end edges of the connecting tape in the front-rear direction have a shape in which concave curves and convex curves are alternately arranged from the base end side to the tip end side,
3. The tape-type disposable diaper according to claim 1, wherein the connecting portion is disposed between a concave curve and a convex curve provided at both ends of the widthwise middle portion of the extending portion of the connecting tape, and is not disposed at any position other than the widthwise middle portion of the extending portion of the connecting tape.

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