Disposable diaper and method of manufacturing the same

Abstract

Provided is a disposable diaper and a method for manufacturing the same, which enables confirmation of whether or not a skin care agent, particularly a moisturizing agent, is applied to the product during the manufacturing process. The disposable diaper has a topsheet that constitutes a use-side front surface, a liquid-impermeable sheet provided on a back surface side, and an absorbent member interposed between the topsheet and the liquid-impermeable sheet, wherein a moisturizing agent containing glycerin as a main component is applied to the topsheet (30), the application area of the moisturizing agent is an exposed area that is directly visible from the use surface side in a laid-out state of the product, at least one of the front-back direction peripheral portion and the width direction peripheral portion in the exposed area has a high-concentration application area (Q) of the moisturizing agent, and a low-concentration application area (MZ) of the moisturizing agent is present in an intermediate area between the high-concentration application areas.

Description

Technical Field

[0001] This invention relates to disposable diapers and their manufacturing methods. Background Technology

[0002] Disposable diapers often cause skin roughness, especially rashes, in the wearer.

[0003] The main reasons include friction between the diaper and the skin during wear, as well as the skin being irritated by bodily fluids and excretions (urine, soft stools) with prolonged wear.

[0004] In particular, irritation caused by prolonged skin contact with soft stool is a major cause. To prevent this, diapers should quickly absorb soft stool into the absorbent core. If the diaper can quickly absorb soft stool into the absorbent core, it will not only reduce skin irritation but also help prevent soft stool from leaking from the legs or back.

[0005] The main reasons that prevent soft stool from being absorbed through the top cover are: First, when soft stool passes through the top cover, the soft stool components that cannot pass through remain on the surface of the fibers that make up the top cover, thus causing blockage; Second, the defecation speed exceeds the diaper's absorption speed, so the stool cannot be absorbed and remains on the top cover.

[0006] Therefore, it is extremely important for diapers to quickly absorb soft stool into the absorbent.

[0007] Patent Document 1 discloses the provision of a skin care agent on the top sheet between the so-called pleats and folds on both sides of the width direction of the diaper, and in particular, the provision of a skin care agent composed of a diamide derivative.

[0008] Especially for diapers worn by infants and young children, diaper rash is common due to their sensitive skin.

[0009] Existing technical documents

[0010] Patent documents

[0011] Patent Document 1: Japanese Patent Application Publication No. 2018-102836 Summary of the Invention

[0012] The problem that the invention aims to solve

[0013] When obtaining diapers formulated with skin-protecting agents to suppress diaper rash, it is extremely important for quality assurance to confirm during the manufacturing process whether the skin-protecting agent has been formulated on the product.

[0014] Therefore, the main objective of this invention is to provide a disposable diaper and a method thereof that allows confirmation during the manufacturing process as to whether a skin care agent, especially a moisturizing agent, is applied to the product.

[0015] Methods for solving problems

[0016] A representative solution for disposable diapers that addresses the above issues is described below.

[0017] <Representative Solutions for Disposable Diapers>

[0018] A disposable diaper includes: a top sheet forming the front side of the diaper; a liquid-impermeable sheet disposed on the back side; and an absorbent member disposed between the top sheet and the liquid-impermeable sheet. The disposable diaper is characterized in that...

[0019] A moisturizer with glycerin as the main component is applied to the top sheet.

[0020] The application area of ​​this moisturizer is the exposed area that is directly visible from the side of the product when it is unfolded.

[0021] At least one of the front-to-back peripheral portion and the width peripheral portion within the exposed area has a high-concentration application area for the moisturizer, and the intermediate region between the high-concentration application areas has a low-concentration application area for the moisturizer.

[0022] In addition, a representative method for manufacturing disposable diapers is described below.

[0023] Representative Scheme for Manufacturing Disposable Diapers

[0024] A method for manufacturing a disposable diaper, the disposable diaper comprising: a top sheet forming the front side of the diaper for use; a liquid-impermeable sheet disposed on the back side; and an absorbent member disposed between the top sheet and the liquid-impermeable sheet.

[0025] The method for manufacturing the disposable diaper is characterized by including the following steps:

[0026] The application process of applying a moisturizer with glycerin as the main component onto the top sheet; and

[0027] An application confirmation process is used to verify whether the aforementioned moisturizer has been applied.

[0028] The application area of ​​the moisturizer is the exposed area that can be directly seen from the side of the product when it is unfolded.

[0029] At least one of the front-to-back peripheral portion and the width peripheral portion within the exposed area has a high-concentration application area for the moisturizer, and the intermediate region between the high-concentration application areas has a low-concentration application area for the moisturizer.

[0030] In the application confirmation process, a near-infrared camera is used to photograph the high-concentration application area, and the presence or absence of moisturizer is confirmed based on the concentration of the photographed image.

[0031] Invention Effects

[0032] According to the present invention, it is possible to confirm during the manufacturing process whether skin care agents, especially moisturizers, are formulated on the product. Attached Figure Description

[0033] Figure 1 This is a top view showing the inner surface of a shorts-type disposable diaper in its unfolded state.

[0034] Figure 2 This is a top view showing the outer surface of a shorts-type disposable diaper in its unfolded state.

[0035] Figure 3 It is along Figure 1 The sectional view along line 2-2 in the diagram.

[0036] Figure 4 It is along Figure 1 A sectional view along line 3-3 in the diagram.

[0037] Figure 5 In the middle, (a) is along Figure 1 (b) is a sectional view along line 4-4 in the diagram. Figure 1 The sectional view along line 5-5.

[0038] Figure 6 This is a 3D diagram of a shorts-style disposable diaper.

[0039] Figure 7 It is a top view used to illustrate the exposed area that can be directly seen from the user side when the product is unfolded.

[0040] Figure 8 This is a top view of an example of how a moisturizer is applied.

[0041] Figure 9 This is a top view showing other applications of moisturizers.

[0042] Figure 10 This is a top view of an example of a high-concentration application area of ​​a moisturizer.

[0043] Figure 11 This is a top view of an example of a high-concentration application area of ​​a moisturizer.

[0044] Figure 12 This is a top view of an example of a high-concentration application area of ​​a moisturizer.

[0045] Figure 13 This is a diagram illustrating the penetration of moisturizers.

[0046] Figure 14 This is an illustrative diagram showing the photographic pattern of a high-concentration application area of ​​the moisturizer, captured by a near-infrared camera. Detailed Implementation

[0047] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The dotted portions in the cross-sectional view represent adhesives used as joining means to connect the constituent parts located on their front and back sides. These adhesives are formed by applying a hot melt adhesive to the entire surface, in a line, curtain, key area, spiral, or pattern (transfer of hot melt adhesive achieved by letterpress printing), or by replacing the adhesive with the fixing portion of the elastic part or by applying the adhesive to the outer peripheral surface of the elastic part using a coating gun or adhesive applicator. Hot melt adhesives include, for example, EVA-based, adhesive rubber-based (elastic system), olefin-based, and polyester polyamide-based adhesives, and can be used without particular limitation. Methods based on material fusion, such as heat sealing or ultrasonic sealing, can also be used as joining means to connect the constituent parts.

[0048] Figures 1-6 An example of a shorts-type disposable diaper is shown. The shorts-type disposable diaper has: a rectangular front outer body 12F, which constitutes at least the waist portion of the front body portion F; a rectangular rear outer body 12B, which constitutes at least the waist portion of the rear body portion B; and an inner body 200, which is disposed inside the outer bodies 12F and 12B in such a way that it extends from the front outer body 12F through the crotch portion to the rear outer body 12B.

[0049] The two sides of the front outer body 12F and the two sides of the rear outer body 12B are joined together to form the side sealing portion 12A. Thus, the openings formed by the front and rear ends of the outer bodies 12F and 12B become waist openings WO for the wearer's waist to pass through. The portions on both sides of the inner body 200 in the width direction, surrounded by the lower edges of the outer bodies 12F and 12B and the side edges of the inner body 200 respectively, become leg openings LO for the legs to pass through. The inner body 200 is the part that absorbs and retains urine and other excrement, while the outer bodies 12F and 12B are the parts that support the inner body 200 relative to the wearer's body. Furthermore, the reference numeral Y indicates the total length of the diaper in the unfolded state (the front-to-back length from the edge of the waist opening WO of the front part F to the edge of the waist opening WO of the rear part B), and the reference numeral X indicates the total width of the diaper in the unfolded state.

[0050] This type of shorts-shaped disposable diaper has a waist region T and a middle region L. The waist region T is defined as the front-to-back direction range with side seals 12A (the front-to-back direction range from the waist opening WO to the upper end of the leg opening LO). The middle region L is defined as the front-to-back direction range of the portion forming the leg opening LO (between the front-to-back direction range with side seals 12A of the front body portion F and the front-to-back direction range with side seals 12A of the back body portion B). The waist region T can be conceptually divided into a "waist" W forming the edge of the waist opening and a portion lower than it, i.e., a "lower waist portion" U. Generally, when there is a boundary within the waist region T where the stretching stress in the width direction WD changes (e.g., the thickness and elongation of the elastic member change), the portion closer to the waist opening WO than the boundary closest to the waist opening WO is called the waist W. When there is no such boundary, the waist extension portion 12E extending from the absorbent body 56 or the inner body 200 toward the waist opening WO is called the waist W. Their front-to-back lengths vary depending on the product size and can be appropriately determined. For example, the waist W can be 15mm to 40mm, and the lower waist U can be 65mm to 120mm. On the other hand, the two sides of the middle area L narrow in a U-shape or curve along the wearer's leg circumference, which is where the wearer's legs are inserted. As a result, the unfolded shorts-type disposable diaper is roughly hourglass-shaped.

[0051] (inner body)

[0052] The internal component 200 can be of any shape, but it is shown as rectangular in the illustration. For example... Figures 3-5 As shown, the inner body 200 has: a top sheet 30 located on the body side; a liquid-impermeable sheet 11; and an absorbent member 50 between them. The inner body 200 is the main body that performs the absorption function. Reference numeral 40 indicates an intermediate sheet (auxiliary sheet) provided between the top sheet 30 and the absorbent member 50 to allow liquid that has passed through the top sheet 30 to move quickly towards the absorbent member 50. Reference numeral 60 indicates side pleats 60 extending from both sides of the inner body 200 to contact the wearer's leg circumference in order to prevent excrement from leaking to both sides of the inner body 200.

[0053] (Top slide)

[0054] The top sheet 30 has the property of allowing liquid to pass through, and examples include porous or non-porous nonwoven fabrics, porous plastic sheets, etc. Furthermore, the type of fiber used in the nonwoven fabric is not particularly limited. Examples include synthetic fibers such as polyethylene or polypropylene (olefins), polyesters, polyamides, man-made fibers or cupra (regenerated fibers), natural fibers such as cotton, or blended fibers or composite fibers formed using two or more of these. Moreover, the nonwoven fabric can be manufactured through any processing. Examples of known processing methods include hydroentangling, spunbonding, hot rolling, meltblowing, needle punching, hot air bonding, and spot bonding. For example, if softness and drape are desired, spunbonding and hydroentangling are preferred processing methods; if fluffiness and softness are desired, hot air bonding, spot bonding, and hot rolling are preferred processing methods.

[0055] Furthermore, the top sheet 30 can be composed of a single sheet or a stack of two or more sheets bonded together. Similarly, the top sheet 30 can be composed of a single sheet or two or more sheets in the planar direction.

[0056] The two sides of the top plate 30 can be folded back towards the rear side from the side edge of the absorber member 50, or they can extend laterally beyond the side edge of the absorber member 50 without folding back.

[0057] For the top sheet 30, to prevent positional displacement relative to the back side components, it is desirable to fix the top sheet 30 to the adjacent component on the back side using a material welding-based joining method such as heat sealing or ultrasonic sealing, or a hot melt adhesive. In the illustrated example, the top sheet 30 is fixed to the front side of the intermediate sheet 40 and the front side of the portion of the packaging sheet 58 located on the front side of the absorber 56 by applying a hot melt adhesive to its back side.

[0058] (Intermediate film)

[0059] To facilitate rapid movement of the liquid through the top plate 30 towards the absorber, an intermediate plate (also called an "auxiliary plate") 40 can be provided, where the liquid permeation speed is faster than that of the top plate 30. This intermediate plate 40 is used to accelerate the liquid's movement towards the absorber, thereby improving the absorbency of the absorber and preventing the absorbed liquid from "backflowing" from the absorber. The intermediate plate 40 can also be omitted.

[0060] As the intermediate sheet 40, the same materials as the top sheet 30 can be used, such as spunlace nonwoven fabric, spunbond nonwoven fabric, SMS nonwoven fabric, pulp nonwoven fabric, a mixture of pulp and synthetic fibers, dot-bonded nonwoven fabric, or crepe paper. Hot-air nonwoven fabric is particularly preferred due to its fluffiness. For hot-air nonwoven fabric, a core-sheath composite fiber is preferred; in this case, the resin used for the core can be polypropylene (PP), but high-rigidity polyester fiber (PET) is preferred. The weight per unit area is preferably 17 g / m². 2 ~80g / m 2 More preferably 25g / m 2 ~60g / m 2 The fineness of the raw fiber for nonwoven fabric is preferably 2.0 dtex to 10 dtex. In order to make the nonwoven fabric fluffy, the mixed fibers used as all or part of the raw fiber are preferably off-center fibers, hollow fibers, or off-center and hollow fibers.

[0061] In the example shown, the middle piece 40 is narrower than the absorbent body 56 and is positioned in the center, but it can also be configured to extend across the entire width. The front-to-back length of the middle piece 40 can be the same as the full length of the diaper, the same as the length of the absorbent member 50, or a shorter length centered on the liquid-receiving area.

[0062] For the intermediate sheet 40, in order to prevent positional displacement relative to the back side component, it is desirable to fix the intermediate sheet 40 to the adjacent component on the back side by means of material welding such as heat sealing or ultrasonic sealing, or by hot melt adhesive. In the example shown, the intermediate sheet 40 is fixed to the front side of the portion of the packaging sheet 58 located on the front side of the absorber 56 by hot melt adhesive applied to its back side.

[0063] (Liqui-impermeable sheet)

[0064] The material of the liquid-impermeable sheet 11 is not particularly limited. Examples include plastic films made of olefin resins such as polyethylene or polypropylene, laminated nonwoven fabrics with plastic films applied to the surface of nonwoven fabrics, and laminated sheets formed by overlapping and bonding nonwoven fabrics on plastic films. For the liquid-impermeable sheet 11, materials with both liquid impermeability and moisture permeability are preferred from the viewpoint of preventing stuffiness. As a moisture-permeable plastic film, microporous plastic films obtained as follows are widely used: inorganic fillers are mixed into olefin resins such as polyethylene or polypropylene, and the film is formed into a sheet and then stretched in a uniaxial or biaxial direction. In addition, as the liquid-impermeable sheet 11, a sheet that is liquid-impermeable without using a plastic film can also be used. This sheet achieves liquid impermeability by: using a nonwoven fabric with micro denier fibers; reducing the fiber porosity by applying heat or pressure, thereby enhancing leak-proof performance; and coating with a superabsorbent resin, a hydrophobic resin, or a water-repellent agent. However, in order to obtain sufficient bonding strength when bonding with the cover nonwoven fabric 13 described later by hot melt adhesive, it is preferable to use a resin film.

[0065] In addition to being formed as shown in the figure with a width that converges on the back side of the absorbent member 50, the impermeable sheet 11 can also extend around both sides of the absorbent member 50 and to both sides of the surface of the absorbent member 50 near the top sheet 30 to improve leak-proof performance. The width of this extension is preferably approximately 5mm to 20mm on each side.

[0066] In addition, an excretion indicator that changes color by absorbing liquid components can be provided on the inner side of the impermeable membrane 11, especially on the surface near the absorber 56.

[0067] (Side pleats)

[0068] Side pleats 60 extend along both sides of the inner body 200 in the front-to-back direction LD. These side pleats 60 are designed to prevent side leakage by contacting the wearer's legs. Generally, structures called three-dimensional pleats and flat pleats are included.

[0069] Figure 1 , Figure 3 , Figure 4 The side pleats 60 shown are so-called three-dimensional pleats, which rise from the side of the inner body 200 toward the front side. Regarding these side pleats 60, the root side portion 60B rises obliquely toward the center side in the width direction, and the end side portion 60A, which is closer to the end side than the middle portion, rises obliquely toward the outside in the width direction. However, it is not limited to this, and it can also be raised as a whole toward the center side in the width direction, etc., and can be modified appropriately.

[0070] To explain in more detail, the side pleats 60 in the example are constructed as follows: a strip of pleated nonwoven fabric 62 having a length equal to the front-to-back length of the inner body 200 is folded back in the width direction WD at the end portion to form two layers, and multiple elongated pleat elastic members 63 are fixed at intervals in the width direction WD between the folded portion and the adjacent sheet, in a state of elongation along the length direction. The base end portion of the side pleat 60 located on the side opposite to the end portion (the end portion on the side opposite to the folded portion in the width direction WD) is a root portion 65 fixed to the side portion of the inner body 200 that is closer to the back side of the liquid-impermeable sheet 11, and the portion other than the root portion 65 is the main body portion 66 (the portion on the folded portion side) extending from the root portion 65. Furthermore, the main body 66 is composed of a root side portion 60B extending towards the center of the width direction and an end side portion 60A that folds back from the end of the root side portion 60B and extends outward in the width direction. This is a surface-contact type side pleat 60, but a line-contact type side pleat 60 that does not fold back outward in the width direction can also be used. Moreover, the two ends of the main body 66 in the front-rear direction are folded portions 67 fixed to the side front of the top plate 30 in a folded state, while the middle part in the front-rear direction between them is a free part 68 that is not fixed. The pleat elastic member 63 along the front-rear direction LD is fixed to at least the end of the free part 68 in an extended state.

[0071] In the side pleats 60 configured as described above, the contractile force of the pleat elastic member 63 acts in a manner that brings the two ends closer together in the front-to-back direction, while the two ends in the main body 66 are fixed in a non-erect manner. In contrast, a free portion 68 is formed between the two ends, thus only the free portion 68... Figure 3 As shown, it stands upright in a way that abuts against the side of the body. In particular, if the root side portion 65 is located on the back side of the inner body 200, the free portion 68 stands upright in the crotch area and its vicinity in a way that opens outward in the width direction, so that the side pleats 60 abut against the legs around the body, thereby improving the fit.

[0072] As shown in the example of the side pleats 60, in the curved shape of the main body 66, which consists of a root side portion 60B extending towards the center in the width direction and an end side portion 60A extending outward in the width direction from the end of the root side portion 60B, at the collapsed portion 67, the end side portion 60A and the root side portion 60B are joined together in the collapsed state, and the root side portion 60B is joined to the top piece 30 in the collapsed state. The joining of the opposing surfaces in the collapsed portion 67 can be achieved using at least one of the following methods: hot melt adhesive based on various coating methods, and material welding based on heat sealing or ultrasonic sealing. In this case, the joining of the root side portion 60B to the top piece 30 and the joining of the end side portion 60A to the root side portion 60B can be performed by the same means or by different means. For example, a preferred method is to join the root side portion 60B to the top piece 30 using a hot melt adhesive and join the end side portion 60A to the root side portion 60B using material welding.

[0073] (Absorbing component)

[0074] The absorbent member 50 includes an absorbent body 56 and a packaging sheet 58 covering the entire absorbent body 56. The packaging sheet 58 may be omitted.

[0075] (Absorber)

[0076] The absorbent 56 can be formed from an aggregate of fibers. Besides an aggregate formed by piling short fibers such as pulp or synthetic fibers, an aggregate of filaments obtained by opening tows (fiber bundles) of synthetic fibers such as cellulose acetate, as needed, can also be used. The weight per unit area of ​​the fiber, in the case of piling short fibers or pulp, can be, for example, approximately 100 g / m². 2 ~300g / m 2 In the case of filament assemblies, for example, it can be approximately 30 g / m³. 2 ~120g / m 2 In the case of synthetic fibers, the fineness is, for example, 1 dtex to 16 dtex, preferably 1 dtex to 10 dtex, and more preferably 1 dtex to 5 dtex. In the case of filament assemblies, the filaments can be non-crimped fibers, but crimped fibers are preferred. The crimp degree of the crimped fibers can be, for example, about 5 to 75 crimps per 2.54 cm, preferably about 10 to 50 crimps, and more preferably about 15 to 50 crimps. In addition, uniformly crimped fibers are used in most cases. It is preferable to disperse and retain the highly absorbent polymer particles in the absorber 56.

[0077] The absorber 56 can be rectangular, but if... Figure 7If the shape is formed as shown in the figure, with a narrower section in the middle of the front-to-back direction that is narrower than the front and back sides, the fit of the absorbent body 56 itself and the side pleats 60 relative to the leg circumference is improved, and therefore it is preferred.

[0078] Additionally, the size of the absorbent 56 can be appropriately determined, as long as it covers the area around the urinary opening, but preferably it extends to or near the periphery of the inner body 200 in the front-to-back direction (LD) and the width direction (WD). Furthermore, the reference numeral 56X indicates the full width of the absorbent 56.

[0079] (Highly absorbent polymer particles)

[0080] The absorbent body 56 may contain part or all of highly absorbent polymer particles. Regarding the highly absorbent polymer particles, in addition to "particles," it also includes "powder." As the highly absorbent polymer particles 54, highly absorbent polymer particles used directly in this disposable diaper can be used, for example, preferably particles whose proportion remaining on the sieve after sieving (shaking for 5 minutes) using a 500 μm standard sieve (JIS Z8801-1:2006) is less than 30% by weight. Furthermore, it is preferable that the proportion of particles remaining on the sieve after sieving (shaking for 5 minutes) using a 180 μm standard sieve (JIS Z8801-1:2006) is more than 60% by weight.

[0081] (Packaging film)

[0082] When using packaging sheet 58, the materials used can include thin paper (especially crepe paper), nonwoven fabric, polyethylene laminated nonwoven fabric, and sheets with small openings. Sheets that do not cause highly absorbent polymer particles to detach are preferred. When using nonwoven fabric instead of crepe paper, hydrophilic SMS nonwoven fabric (SMS, SSMMS, etc.) is particularly suitable, and its material can be polypropylene, polyethylene / polypropylene composites, etc. The preferred weight per unit area is 5 g / m². 2 ~40g / m 2 The preferred value is 10g / m 2 ~30g / m 2 .

[0083] The packaging structure of the packaging sheet 58 can be appropriately determined, but from the viewpoint of ease of manufacturing and prevention of leakage of highly absorbent polymer particles from the front and rear ends, the following structure is preferred: the packaging sheet 58 is wound into a cylindrical shape to surround the front and back sides and both sides of the absorber 56, and the front and rear edges of the packaging sheet 58 extend from the front and rear of the absorber 56, and the overlapping parts of the winding and the overlapping parts of the front and rear protruding parts are joined together by joining means such as hot melt adhesive or material welding.

[0084] (outer body)

[0085] The outer garments 12F and 12B are composed of a rectangular front outer garment 12F constituting at least the waist portion of the front body part F, and a rectangular rear outer garment 12B constituting at least the waist portion of the rear body part B. The front outer garment 12F and the rear outer garment 12B are discontinuous at the crotch side and are separated in the front-rear direction LD. This separation distance 12d can be, for example, approximately 150mm to 250mm. As described in Patent Document 4, the outer garments 12F and 12B can also be a continuous, integral outer garment extending from the front body part F through the crotch to the rear body part B.

[0086] The outer garments 12F and 12B have a front-to-back range corresponding to the waist region T, i.e., a waist portion. In addition, in this embodiment, the front-to-back dimension of the rear outer garment 12B is longer than that of the front outer garment 12F, and the front outer garment 12F does not have a portion corresponding to the middle region L, but the rear outer garment 12B has a buttock cover portion C extending from the waist region T toward the middle region L.

[0087] To improve the fit to the wearer's waist, elastic members 15 to 19 are built into the outer garments 12F and 12B, forming a stretchable region A2 that elastically stretches and contracts in the width direction WD as the elastic members expand and contract. In this stretchable region A2, at their natural length, the outer garments 12F and 12B contract as the elastic members contract, forming wrinkles or folds. When the outer garments 12F and 12B extend in the length direction of the elastic members, they can extend to a predetermined elongation rate such that they can reach their maximum elongation without wrinkling. As the elastic members 15 to 19, in addition to elongated elastic members such as rubber threads (example shown in the figure), known elastic members such as strips, meshes, and films can also be used without particular limitation. Synthetic rubber or natural rubber can be used as the elastic members 15 to 19.

[0088] The elastic members 15-19 in the example diagram will be described in more detail. Multiple waist elastic members 17 are installed at intervals in the front-to-back direction at the waist W of the outer bodies 12F and 12B, in a continuous manner covering the entire width direction WD. Furthermore, for one or more waist elastic members 17 located in the area adjacent to the lower waist U, they can either overlap with the inner body 200, or the central portion overlapping with the inner body 200 in the width direction can be removed, and they can be respectively provided on both sides in the width direction. Preferably, approximately 2 to 15 waist elastic members 17 (especially preferably approximately 4 to 10) are provided at intervals of 2 mm to 12 mm (especially preferably 3 mm to 7 mm), with a thickness of 155 dtex to 1880 dtex (especially preferably approximately 470 dtex to 1240 dtex) (in the case of synthetic rubber; in the case of natural rubber, the cross-sectional area is 0.05 mm²). 2 ~1.5mm 2 Especially preferred is approximately 0.1 mm. 2 ~1.0mm 2 The rubber thread of the waist section W has an elongation of 150% to 400% in the width direction WD, and is particularly preferably about 220% to 320%. Furthermore, for the waist section W, it is not necessary to use the same thickness of the waist elastic member 17 or to set the same elongation in both its front-rear directions LD; for example, the thickness or elongation of the elastic member 17 can be different in the upper and lower parts of the waist section W.

[0089] Furthermore, it is preferable that multiple elongated elastic members 15 and 19, each composed of a thin elastic component, are installed at intervals in the front-to-back direction at the lower waist portion U of the outer casing 12F and 12B. As the lower waist elastic members 15 and 19, it is preferable that approximately 5 to 30 members with a thickness of 155 dtex to 1880 dtex, and particularly preferably approximately 470 dtex to 1240 dtex (in the case of synthetic rubber; in the case of natural rubber, the cross-sectional area is 0.05 mm²) are provided at intervals of 1 mm to 15 mm, and particularly preferably 3 mm to 8 mm. 2 ~1.5mm 2 Especially preferred is approximately 0.1 mm. 2 ~1.0mm 2 The rubber cord of the waist section U has an elongation of 200% to 350% in the width direction WD, which is particularly preferably about 240% to 300%.

[0090] Furthermore, it is preferable that a cover elastic member 16, composed of an elongated elastic member, is installed in the buttock cover portion C of the rear outer body 12B. The buttock cover portion C contracts towards the center side in the width direction WD by means of the cover elastic member 16. As the cover elastic member 16, it is preferable to have a thickness of 155 dtex to 1880 dtex (especially preferably about 470 dtex to 1240 dtex) (in the case of synthetic rubber; in the case of natural rubber, the cross-sectional area is 0.05 mm). 2 ~1.5mm 2 Especially preferred is approximately 0.1 mm. 2 ~1.0mm 2 The rubber thread of the buttock cover C, based on this configuration, has an elongation of 150% to 300% in the width direction WD, and is particularly preferably 180% to 260%.

[0091] In the above example, although the outer components 12F and 12B are separate front and back, they can also be continuous (not shown).

[0092] (Moisturizers and their applications)

[0093] In order to keep the wearer's skin in good condition and to prevent diaper rash, it is preferable to apply a moisturizer to the top sheet 30 in the manner described in the examples below.

[0094] Ideally, the moisturizer should be glycerin as its main component. When the moisturizer is applied to the outer surface of the top sheet 30 (at least the outer surface of the top sheet 30 contains moisturizer M), the moisturizer M protects the wearer's skin.

[0095] Furthermore, the moisturizing agent M also reduces friction between the diaper and the wearer's skin. As a result, when wearing a disposable diaper, the top piece slides relative to the skin as the wearer's posture changes, thereby ensuring contact with the wearer's skin and improving leak-proof performance.

[0096] A humectant with glycerin as its main component contains 70% or more glycerin by mass. Depending on the requirements, it may contain one or more additives selected from emulsifiers, phosphate esters, paraffin wax, and surfactants. As surfactants, ether-type nonionic surfactants and nonionic surfactants containing EO / PO types are preferred.

[0097] like Figure 13As schematically shown, the top sheet 30 is preferably a perforated nonwoven fabric with a plurality of openings 14 spaced apart through both sides. The presence of openings 14 through both sides in the top sheet 30 allows soft stool components to be rapidly absorbed by the absorbent member 50 having absorbent core 56 through the openings 14. This not only reduces skin irritation caused by soft stool components remaining on the surface of the top sheet 30, thus suppressing diaper rash, but also helps prevent soft stool leakage from the legs or back.

[0098] In the general manufacturing method of diapers, during the diaper manufacturing process, a moisturizing agent M is applied to the top sheet 30 by means of coating or other methods. Afterwards, multiple diaper products are tightly packaged. By compressing the diapers in this way, such as... Figure 13 As illustrated, a portion of the humectant M in the top sheet 30 is transferred to the middle sheet 40 through the opening 14.

[0099] The permeation rate of bodily fluids in the intermediate sheet is generally faster than that in the top sheet 30. Furthermore, the humectant M, whose main component is glycerin, is more hydrophilic than the hydrophilic diamide derivative. As a result, the humectant M, whose main component is glycerin, transferred to the intermediate sheet 40 side, acts to introduce bodily fluids from the top sheet 30 side or softening components through the opening 14.

[0100] Therefore, bodily fluids from the top sheet 30 side or soft stool components through the opening 14 are rapidly guided to the absorbent member 50 side, thereby inhibiting the residue of bodily fluids such as soft stool components on the surface of the top sheet 30, thus reducing skin irritation and suppressing diaper rash.

[0101] Moisturizers function when applied to areas that come into contact with the wearer's skin. In the above embodiment, this area is... Figure 7 The area between the side pleats 60, 60 shown. That is, the area between the side pleats 60, 60 is the applicable area Z in this invention.

[0102] In other words, the applicable area Z is the exposed area Z that can be directly seen from the user side when the product is unfolded.

[0103] The moisturizer can be applied to the appropriate area within the applicable area (exposed area) Z. For example, as... Figure 8 As shown, since the skin in the Z1 area on the B side of the posterior body where the buttocks are located tends to be dry, the amount of moisturizer applied can be increased. And since the Z2 area corresponding to the crotch area tends to be moist, the amount of moisturizer applied can be reduced.

[0104] In other words, this is a method that involves multiple application areas Z1 and Z2 with different concentrations of moisturizer in the front and back directions within a low-concentration application area.

[0105] Furthermore, regarding the application of a moisturizing agent to the top sheet 30, it can be applied in its original state before combining with other diaper constituent materials, such as before combining with the constituent materials of the side pleats 60. Therefore, for example, the moisturizing agent can be applied across the entire width of the top sheet 30 material, extending beyond the applicable area (exposed area) Z in the width direction. Based on this viewpoint, it can be clearly defined that the moisturizing agent is applied to the exposed area that is "at least" directly visible from the use side when the product is unfolded.

[0106] The groin area is the part of the body that comes into frequent contact with soft stool components. To address this, when considering the need to increase the amount of moisturizer applied, such as... Figure 9 As shown, the amount of application in the central region Z3 can be greater (higher concentration) than that in the rear region Z1 and the front region Z2.

[0107] As a method of applying humectant to the top sheet, appropriate methods can be used, such as non-contact application to key areas, spiral application, marking application, single-fluid or two-fluid spray application, contact application to gaps, or printing-type hammer roller application.

[0108] On the other hand, when the amount of moisturizer applied is increased (the concentration is increased), the moisturizer will adhere too much to the skin and make people feel sticky, which may cause discomfort to the wearer.

[0109] Therefore, there is an upper limit to the amount of moisturizer that can be used.

[0110] On the other hand, when diapers with moisturizing agents are obtained, it is extremely important in terms of quality assurance (i.e., in terms of defective product removal management) to confirm whether moisturizing agents have been applied to the product during the manufacturing process.

[0111] To make this confirmation, since the moisturizer contains water, which is absorbed in the near-infrared band, the following method can be considered: for example, setting up a near-infrared camera on the production line and taking pictures of the application area of ​​the moisturizer, and confirming the presence or absence of moisturizer based on the concentration of the captured image.

[0112] However, the results of various experiments showed that when the amount of humectant applied was small, the concentration difference in the images captured by the near-infrared camera could not be detected.

[0113] However, if the amount of moisturizer applied is increased (increasing the concentration) in order to detect the concentration difference in images taken with a near-infrared camera, the moisturizer will adhere too much to the skin, making people feel sticky and potentially causing discomfort to the wearer.

[0114] To solve this problem, it was discovered that: the exposed area (applicable area) Z (reference) can be... Figure 7 A high-concentration application area Q of a humectant is formed on at least one of the periphery in the front-back direction and the periphery in the width direction within the ), and the humectant is applied at a low concentration to the intermediate area between the high-concentration application areas Q and Q.

[0115] This is because even if there is a high concentration of application area Q, this area is not an area where too much moisturizer adheres to the wearer's skin, making it feel sticky or uncomfortable.

[0116] Furthermore, for example, it can be achieved by adopting Figures 10-12 The method shown utilizes a near-infrared camera to image and detect the high-concentration application area Q.

[0117] Figure 10 An example is setting the high-concentration application area (marked area) Q before and after the top sheet 30. The low-concentration application area MZ of the humectant is located between the high-concentration application areas (marked areas) Q and Q'.

[0118] Figure 11 An example is where the high-concentration application area (marking area) Q is located on the left and right sides of the top sheet 30. The low-concentration application area MZ of the humectant is located between the high-concentration application areas (marking areas) Q and Q'.

[0119] Figure 12 An example is where the high-concentration application area (marked area) Q is positioned at the front, back, left, and right sides of the top sheet 30. The low-concentration application area MZ of the humectant is located within the area surrounded by the high-concentration application area (marked area).

[0120] exist Figures 10-12 In the example, within the low-concentration application area of ​​the exposed area (applicable area) Z, the moisturizer can be applied along the front-to-back direction at intervals in the width direction. In this method, manufacturing is facilitated because the flow direction of the production line is aligned with the application flow of the moisturizer.

[0121] Figure 14 An outline of the imaging process for a high-concentration application area (labeled area) Q is shown. That is, for example, in... Figure 10 In the application method, a near-infrared camera 100 is installed in the production line where the connecting part of the semi-finished disposable diaper flows laterally in the direction of the arrow (right direction) to capture the high-concentration application area (marked area) Q.

[0122] The near-infrared wavelength range is generally 780nm to 2500nm. The 1400nm and 1900nm wavelengths are absorbed by water. Therefore, detection using a near-infrared camera 100 is effective.

[0123] The inventors conducted the following experiments and various studies to confirm whether the product contained skin care agents, especially moisturizers.

[0124] (1) Surface material of absorbent materials (hydrophilic breathable nonwoven fabric 18g / m²) 2 The coating is applied to the surface of the 2.0 / 2.2 dtex material using a two-fluid jet and a critical area coating method, while varying the coating concentration per unit area.

[0125] The application concentration was set to 0.1 g / m³. 2 0.5g / m 2 2.0g / m 2 5g / m 2 8.5g / m 2 .

[0126] (2) Cut the above sample into 5cm×5cm pieces to make test pieces.

[0127] (3) Using a near-infrared camera (NIRCam-640SN) manufactured by Vision Sensing, the test piece was illuminated from above (indoor light + external light from the window) and photographed.

[0128] Based on the above experiments, it can be seen that as long as the concentration of the moisturizer is 8.5g / m³, the moisturizer will be effective. 2 With a value of (0.022g / (5cm×5cm)) or higher, a near-infrared camera 100 can detect and distinguish the signal with sufficient sensitivity.

[0129] Additionally, based on monitoring data from 10 adults, if the concentration of the moisturizer applied is 15g / m²... 2 A weight of 0.025g / (5cm×5cm) or more will cause a sticky feeling.

[0130] The preferred application amount is 0.02–0.04 g / (5cm × 5cm).

[0131] In an embodiment of the present invention, the application area MZ of the low concentration of the humectant is located within the area surrounded by the application area (marked area) Q of the high concentration.

[0132] In the low-concentration application area MZ, the preferred concentration is 0.1–8.5 g / m³. 2If the concentration is too low, the moisturizer will not be effective enough; if the concentration is too high, it will make people feel sticky.

[0133] On the other hand, in order to make a determination, the ratio of the concentration of the high-concentration application area (marked area) Q of the moisturizer to the concentration of the low-concentration application area MZ is preferably 1.5 or more.

[0134] <Explanation of terms used in the instruction manual>

[0135] Unless otherwise specified in the instruction manual, the following terms in the instruction manual shall have the following meanings.

[0136] • “Front-back (longitudinal) direction” refers to the direction that connects the ventral (front) and dorsal (back) sides, while “width direction” refers to the direction perpendicular to the front-back direction (left-right direction).

[0137] • "Front side" refers to the side closest to the wearer's skin when wearing a shorts-type disposable diaper, while "back side" refers to the side furthest from the wearer's skin when wearing a shorts-type disposable diaper.

[0138] • "Front" refers to the side of the diaper that is closest to the wearer's skin when wearing a shorts-type disposable diaper, while "back" refers to the side that is furthest from the wearer's skin when wearing a shorts-type disposable diaper.

[0139] • "Elongation" refers to the value when the natural length is set to 100%.

[0140] • The gel strength was determined as follows. 1.0 g of highly absorbent polymer was added to 49.0 g of artificial urine (a mixture of urea: 2 wt%, sodium chloride: 0.8 wt%, calcium chloride dihydrate: 0.03 wt%, magnesium oxide heptahydrate: 0.08 wt%, and ion-exchanged water: 97.09 wt%) and stirred using a mixer. The resulting gel was placed in a constant temperature and humidity bath at 40℃ × 60% RH for 3 hours, then allowed to return to room temperature. The gel strength was measured using a curdmeter (manufactured by I.techno Engineering: Curdmeter-MAX ME-500).

[0141] • The weight per unit area is determined as follows. After pre-drying, the sample or test piece is placed in a test chamber or apparatus under standard conditions (temperature 23±1℃, relative humidity 50±2% or less) to achieve a constant weight. Pre-drying refers to bringing the sample or test piece to a constant weight at a temperature of 100℃. Alternatively, for fibers with a standard moisture regain of 0.0%, pre-drying may not be necessary. Using a template (100mm×100mm) for sample selection, a 100mm×100mm sample is cut from the constant-weight test piece. The weight of the sample is measured, and the weight per square meter is calculated as 10 times the weight of the sample as the weight per unit area.

[0142] • Thickness was measured using an automatic thickness gauge (KES-G5 portable compression measurement program) at a load of 0.098 N / cm. 2 Pressurized area: 2cm² 2 Automatically measured under certain conditions.

[0143] • The water absorption is determined according to JIS K7223-1996 "Test method for water absorption of superabsorbent resins".

[0144] • The water absorption rate is the time to the endpoint when using 2g of superabsorbent polymer and 50g of physiological saline to perform the test method for water absorption rate of superabsorbent resin in JIS K7224-1996.

[0145] • "Unfolded state" refers to a state in which the body is flat and unfolded without shrinking or relaxing.

[0146] Unless otherwise specified, the dimensions of each part refer to the dimensions in the unfolded state, not in the natural length state.

[0147] • Unless otherwise specified, the test or measurement was conducted in a laboratory or apparatus under standard conditions (temperature 23±1℃ and relative humidity 50±2%).

[0148] Industrial availability

[0149] In addition to shorts-type disposable diapers, this invention can also be applied to belt-type disposable diapers, disposable diaper pads used to attach to disposable diapers, etc.

[0150] Label Explanation

[0151] 11: Liquid-impermeable sheet; 12A: Side seal; 12B: Rear outer casing; 12E: Waist extension; 12F: Front outer casing; 12F, 12B: Outer casing; 12H: Second sheet; 12S: First sheet; 13: Cover nonwoven fabric; 15, 19: Elastic components below waist; 16: Cover elastic component; 17: Waist elastic component; 18: Unnecessary elastic component; 200: Inner casing; 30: Top sheet; 40: Middle sheet; 50: Absorbent component; 56: Absorbent body; 58: Packaging sheet; 60: Side pleats; 62: Pleated nonwoven fabric.

Claims

1. A disposable diaper comprising: a top sheet forming the front side of the diaper for use; a liquid-impermeable sheet disposed on the back side; and an absorbent member disposed between the top sheet and the liquid-impermeable sheet, characterized in that, A moisturizer containing more than 70% by weight of glycerin is applied to the top sheet. The application area of ​​this moisturizer is the exposed area that is directly visible from the side of the product when it is unfolded. Within the exposed area, the product is spaced laterally at intervals along its front and back sides for imaging with a near-infrared camera, and has a concentration of 8.5 g / m³. 2 The above-mentioned high-concentration application areas of the moisturizer include an intermediate region with a skin-protecting concentration of 0.1 g / m². 2 ~8.5g / m 2 Low concentration application areas of the moisturizer.

2. The disposable diaper according to claim 1, characterized in that, Within the low-concentration application area, there are multiple application areas with different concentrations of humectant in the front-to-back direction.

3. The disposable diaper according to claim 1, characterized in that, Within the low-concentration application area, the moisturizer is applied along the front-to-back direction with intervals spaced apart in the width direction.

4. The disposable diaper according to claim 1, characterized in that, The application concentration of the moisturizer in the high-concentration application area is 8.5 g / m². 2 ~15g / m 2 .

5. A method for manufacturing a disposable diaper, the disposable diaper comprising: a top sheet forming the front side of the diaper for use; a liquid-impermeable sheet disposed on the back side; and an absorbent member disposed between the top sheet and the liquid-impermeable sheet. The method for manufacturing the disposable diaper is characterized in that, The method for manufacturing the disposable diaper includes the following steps: An application process in which a moisturizer containing 70% by mass or more glycerin is applied to the top sheet; and An application confirmation process is used to verify whether the moisturizer has been applied. The application area of ​​the moisturizer is the exposed area that can be directly seen from the side of the product when it is unfolded. Within the exposed area, the product is spaced laterally at intervals along its front and back sides for imaging with a near-infrared camera, and has a concentration of 8.5 g / m³. 2 The above-mentioned high-concentration application areas of the moisturizer include an intermediate region with a skin-protecting concentration of 0.1 g / m². 2 ~8.5g / m 2 Application areas of low concentration of moisturizers, In the application confirmation process, a near-infrared camera is used to photograph the high-concentration application area, and the presence or absence of moisturizer is confirmed based on the concentration of the photographed image.

Images