Absorbent article and method for manufacturing the same

Abstract

The present invention provides an absorbent article having a new design printing section suitable for a stretchable area. The above problem is solved by an absorbent article characterized in that the absorbent article has an elastic film stretching structure (20X), in which an elastic film (30) is laminated between a first sheet layer (20A) and a second sheet layer (20B), and the first sheet layer (20A) and the second sheet layer (20B) are joined directly or with the elastic film (30) interposed therebetween at a plurality of sheet joining portions (40) arranged at intervals, and an area having the elastic film stretching structure (20X) has a stretchable area (80) that contracts in the stretching direction by the contraction force of the elastic film (30) and can be elongated in the stretching direction, and a design printing section (33) is provided on a portion of the elastic film (30) located in the stretchable area (80).

Description

Technical Field

[0001] The present invention relates to an absorbent article having a stretchable region and a method for manufacturing the same, the stretchable region having a design printed portion. Background Art

[0002] Designs such as patterns for decoration (including figures with paintings and single-point patterns), usage methods or usage aids, size and other function displays, or identification displays such as manufacturer or product names and characteristic functions are printed on absorbent articles (for example, refer to Patent Documents 1 and 2).

[0003] Regarding conventional design printed portions, in addition to printing on materials such as non-woven fabrics that form the outer surface of absorbent articles, generally, a sheet on which printing has been performed is pasted onto the absorbent article.

[0004] However, if these conventional methods are applied to a stretchable region, deformation of the design due to stretching increases, and thus there is a problem that it is not suitable for the stretchable region. In addition, it is also a problem that an elegant appearance like that of a fabric product cannot be obtained. For example, if printing is performed on the material of the stretchable region, wrinkles or folds are formed in the printing material of the design in the natural length state, thereby impairing the aesthetics.

[0005] Prior Art Documents

[0006] Patent Documents

[0007] Patent Document 1: Japanese Patent Application Laid-Open No. 2015-515920

[0008] Patent Document 2: Japanese Patent No. 5695789

[0009] Patent Document 3: Japanese Patent Application Laid-Open No. 2004-532758

[0010] Patent Document 4: Japanese Patent Application Laid-Open No. 2009-536845

[0011] Patent Document 5: Japanese Patent Application Laid-Open No. 2011-136095

[0012] Patent Document 6: Japanese Patent No. 5250372 Summary of the Invention

[0013] Problems to be Solved by the Invention

[0014] Therefore, the main problem of the present invention is to provide an absorbent article having a new design printed portion suitable for a stretchable region.

[0015] Means for Solving the Problems

[0016] The present invention that solves the above problems is as follows.

[0017] <Invention according to Technical Solution 1>

[0018] An absorbent article, characterized in that the absorbent article has an elastic film expansion and contraction structure, in which an elastic film is laminated between a first sheet layer and a second sheet layer, and the first sheet layer and the second sheet layer are directly or via the elastic film joined together at a plurality of sheet joining portions arranged at intervals, and a region having the elastic film expansion and contraction structure has an expandable and contractible expansion region, the expansion region contracts in the expansion direction by the contraction force of the elastic film and can be elongated in the expansion direction, and a design drawing printing portion is provided at a portion of the elastic film located in the expansion region.

[0019] (Function and effect)

[0020] In the present invention, an elastic film expansion and contraction structure is adopted, and a design drawing printing portion such as a pattern is provided on a portion of the elastic film located in the expansion region. Since the elastic film does not form wrinkles or pleats due to expansion and contraction, in the present invention, deformation of the design drawing caused by the formation of wrinkles or pleats on the printing object of the design drawing does not occur. In addition, in the present invention, in addition to the advantage that it does not affect the expandability of the expansion region at all, there are also the following advantages: compared with non-woven fabric, the surface of the elastic film is excellent in printing applicability; and since the printing surface of the elastic film is covered by the first sheet layer and the second sheet layer, printing is difficult to peel off.

[0021] <Invention according to Technical Solution 2>

[0022] The absorbent article according to Technical Solution 1, wherein the sheet joining portion is a portion where the first sheet layer and the second sheet layer are welded together via a through hole penetrating the elastic film, and is a portion where a concave portion is formed on a non-opposing surface of the first sheet layer and the second sheet layer, and either the first sheet layer or the second sheet layer is a small uneven layer where the concave portion is shallower than the concave portion of the other, and the design drawing printing portion is provided on a surface of the elastic film on the side of the small uneven layer.

[0023] (Function and effect)

[0024] For example, when the sheet joint is welded by ultrasonic sealing, the concave and convex parts formed on the sheet layer on the supporting roller side become deeper, and the concave parts on the sheet layer on the opposite side become shallower. The same is true when heat sealing. In the present invention, the sheet layer on the side where the concave part is shallower is called a small concave and convex layer. In the elastic film telescopic structure of the present invention, for the design drawing printed part on the elastic film, the design drawing printed part is observed through the first sheet layer or the second sheet layer. Therefore, as described in this item, if the design drawing printed part is set on the small concave and convex layer side with smaller concave and convex, there is an advantage that the aesthetics of the design drawing printed part becomes better.

[0025] <Invention according to claim 3>

[0026] The absorbent article according to claim 1 or 2, wherein the stretchable region is stretchable in only one direction, and a transverse shrinkage ratio of the elastic film in a direction perpendicular to the stretching direction is 25% or less.

[0027] (Effect)

[0028] When the elastic film is stretched in one direction, the width in the direction perpendicular to the stretching direction becomes narrower as it moves toward the center of the stretching direction, corresponding to the amount of stretching. This is called lateral contraction (or shrinkage). When the elastic film is contracted from this state to its natural length, the width is also restored. Regarding the stretchable area in the absorbent article, in many cases, the amount of stretch in the stretching direction changes according to the position in the direction perpendicular to the stretching direction to adapt to the body surface composed of complex curved surfaces. In such a case, the degree of lateral contraction also changes according to the position in the direction perpendicular to the stretching direction. Therefore, when the design printing part is provided on the elastic film in the part located in the stretching area as in the present invention, if the amount of stretch in the stretching direction changes according to the position in the direction perpendicular to the stretching direction, the deformation amount of the design printing part caused by the lateral contraction of the elastic film also changes according to the position in the direction perpendicular to the stretching direction, and there is a concern that the aesthetics will deteriorate. Therefore, when the design printing part is provided on the elastic film in the portion located in the stretchable region as in the present invention, it is desirable to reduce the transverse shrinkage ratio as described in this item, and it is particularly desirable to reduce the transverse shrinkage ratio to 25% or less. The definition of "transverse shrinkage ratio" is as described below.

[0029] <Invention according to Claim 4>

[0030] The absorbent article according to any one of claims 1 to 3, wherein the elastic film stretch structure has a plurality of regions having different elastic limit elongations, and the design pattern printed portion is not provided at the boundary between the plurality of regions and at portions adjacent to both sides of the boundary on the elastic film.

[0031] (Effect)

[0032] When the design drawing printing part is provided on the elastic film, the design drawing printing part deforms as the elastic film expands and contracts. In this case, as long as the whole of the design drawing printing part expands and contracts in the same manner, the shape of the design drawing printing part also deforms in the same manner, so the balance of the whole design drawing printing part is not destroyed. However, the elastic film expansion and contraction structure has the advantage of having a plurality of regions with different elastic limit elongation rates and being able to correspond to changes in parts to adjust the fit, etc. In the case of having a plurality of regions with different elastic limit elongation rates like this, if there is a design drawing printing part that straddles the boundary of the regions, there is a concern that the design drawing printing part does not deform in the same manner on both sides of the boundary, resulting in deterioration of the aesthetics. Therefore, in the case of having a plurality of regions with different elastic limit elongation rates, the following method is also a preferred method: as described in this item, there is no design drawing printing part at the boundary of the plurality of regions and in the parts adjacent to both sides of the boundary.

[0033] <The invention according to claim 5>

[0034] The absorbent article according to any one of claims 1 to 4, wherein the absorbent article is a short-type disposable diaper, and the short-type disposable diaper includes: an outer package body that constitutes a front body part and a rear body part; an inner package body containing an absorbent body, which is fixed to the outer package body; side seal parts that are formed by joining together the two side parts of the outer package body in the front body part and the two side parts of the outer package body in the rear body part respectively; an annular waist part; and a waist opening and a pair of left and right leg openings, and the outer package body in at least one of the front body part and the rear body part has the elastic film expansion and contraction structure in the entire width direction range corresponding to at least a part in the front-rear direction between the side seal parts, wherein the expansion and contraction direction of the expansion and contraction region of the elastic film expansion and contraction structure is the width direction.

[0035] (Function and effect)

[0036] Regarding the short-type disposable diaper, even in the absorbent article, its expansion and contraction region is relatively large, and it is mostly used as a substitute for underwear, so patterns and other design drawing printing parts are mostly provided in the expansion and contraction region, and aesthetics is very important. Therefore, the present invention is suitable for the expansion and contraction region of such a short-type disposable diaper.

[0037] <The invention according to claim 6>

[0038] A method for manufacturing an absorbent article, which is a method for manufacturing an absorbent article having an elastic film stretching structure, the elastic film stretching structure including a stretching region capable of stretching in one direction, characterized in that when forming the elastic film stretching structure, while stretching the elastic film in the stretching direction of the stretching region and sandwiching the elastic film between a first sheet layer and a second sheet layer, the first sheet layer and the second sheet layer are directly or through the elastic film joined together at a plurality of spaced-apart positions to form a sheet joint portion, and an elastic film pre-printed with a design printing portion at a portion that becomes the stretching region is used as the elastic film, or before the elastic film is stretched, a design printing portion is printed on a portion of the elastic film that becomes the stretching region on a production line.

[0039] (Function and effect)

[0040] It is possible to manufacture the absorbent article of Technical Solution 1.

[0041] <The invention according to Technical Solution 7>

[0042] According to the method for manufacturing an absorbent article described in Technical Solution 6, wherein when forming the elastic film stretching structure, while stretching the elastic film in the stretching direction of the stretching region and sandwiching the elastic film between the first sheet layer and the second sheet layer, the elastic film, the first sheet layer, and the second sheet layer are ultrasonically sealed by passing through between a support roller and an ultrasonic welding head, and the first sheet layer and the second sheet layer are directly joined together to form the sheet joint portion, and the elastic film is supplied in such a manner that the design printing portion is provided on a surface of the elastic film opposite to the support roller side.

[0043] (Function and effect)

[0044] It is possible to manufacture the absorbent article of Technical Solution 2. In particular, according to this manufacturing method, for the folds formed on the first sheet layer and the second sheet layer in the stretching region in the natural length state, compared with the support roller side, one of the sheet layers on the opposite side is formed more neatly and beautifully, and thus, from this point of view, the aesthetics of the design printing portion is also improved.

[0045] <The invention according to Technical Solution 8>

[0046] According to the method for manufacturing an absorbent article described in Technical Solution 6 or 7, wherein the lateral shrinkage ratio of the elastic film in a direction perpendicular to the stretching direction is 25% or less.

[0047] (Function and effect)

[0048] An absorbent article capable of manufacturing the technical solution 3 can be produced. In particular, if an elastic film with a low lateral shrinkage ratio as described in this item is used, the manufacturing stability is improved, and it is also suitable for on-line printing.

[0049] <The invention according to claim 9>

[0050] According to the method for manufacturing an absorbent article according to any one of claims 6 to 8, when forming the elastic film stretching structure, a plurality of stretching regions with different elastic limit elongation rates are formed by making the patterns of the sheet joint portions different, and the design drawing printing portion is printed at the portions of the elastic film that become the plurality of regions. And when performing this printing, a deformed design drawing is printed as follows: for a region with a smaller elastic limit elongation rate, this deformed design drawing shrinks and deforms in the stretching direction at a higher deformation rate.

[0051] (Function and effect)

[0052] When the design drawing printing portion is provided on the elastic film, the design drawing printing portion deforms as the elastic film stretches and contracts. In this case, as long as the whole of the design drawing printing portion stretches and contracts in the same manner, the shape of the design drawing printing portion also deforms in the same manner, so the balance of the whole design drawing printing portion is not destroyed. However, the elastic film stretching structure has the following advantages: by making the patterns of the sheet joint portions different, a plurality of stretching regions with different elastic limit elongation rates are provided, so that the fit or stretchability / non-stretchability can be changed according to the part. Such a plurality of regions with different elastic limit elongation rates are formed due to the following factors: after the tension applied to the first sheet layer, the second sheet layer, and the elastic film between them is released by cutting into individual products or parts during the manufacturing process and after forming the sheet joint portion, the difference in the shrinkage recovery amount of the elastic film. The shrinkage recovery amount of the elastic film (including the non-stretching state where it hardly shrinks) is lower than the elongation rate of the elastic film that has been elongated before forming the sheet joint portion, and the degree of this decrease can be changed by the pattern of the sheet joint portion. Therefore, if the design drawing printing portion is provided in the same manner at the portions of the elastic film that become the plurality of regions, in the natural length state or the wearing state, the degree of deformation of the design drawing printing portion in the stretching direction is different for each region, resulting in deterioration of the aesthetics.

[0053] In contrast, as described in this item, if a deformed design drawing is printed as follows: for a region with a smaller elastic limit elongation rate, that is, a region with a smaller shrinkage recovery amount after stretching the elastic film and forming the sheet joint portion, this deformed design drawing shrinks and deforms in the stretching direction at a higher deformation rate, then the difference in the deformation of the design drawing printing portion in the stretching direction between the regions becomes smaller, and deterioration of the aesthetics can be prevented. Here, the deformation rate is a quantity that represents the ratio of the length difference before and after shrinkage deformation to the length before shrinkage deformation as a percentage.

[0054] <The invention according to Technical Solution 10>

[0055] The manufacturing method of the absorbent article according to any one of Technical Solutions 6 to 9, wherein when forming the elastic film stretching structure, a plurality of regions with different elastic limit elongation rates of the product are formed, and a design pattern printing portion is not printed at the boundaries of the plurality of regions on the elastic film and at portions adjacent to both sides of the boundary.

[0056] (Function and effect)

[0057] The absorbent article of Technical Solution 4 can be manufactured.

[0058] Effect of the invention

[0059] As described above, according to the present invention, there are advantages as follows: an absorbent article having a new design pattern printing portion suitable for the stretching region is obtained. Description of the drawings

[0060] Figure 1 It is a top view (inner surface side) of a short-pants type disposable diaper in an unfolded state.

[0061] Figure 2 It is a top view (outer surface side) of a short-pants type disposable diaper in an unfolded state.

[0062] Figure 3 It is a top view showing only the important part of a short-pants type disposable diaper in an unfolded state.

[0063] Figure 4 (a) of [] is a cross-sectional view taken along the C-C line of Figure 1 of [], Figure 4 and (b) of [] is a cross-sectional view taken along the E-E line of Figure 1 of [].

[0064] Figure 5 It is a cross-sectional view taken along the A-A line of Figure 1 of [].

[0065] Figure 6 It is a cross-sectional view taken along the B-B line of Figure 1 of [].

[0066] Figure 7 (a) of [] is a top view of the important part of the stretching region, Figure 7 and (b) of [] is a cross-sectional view taken along the D-D line of Figure 7 (a) of [], Figure 7 (c) of [] is a cross-sectional view in a worn state, Figure 7 (d) of [] is a cross-sectional view in a natural length state.

[0067] Figure 8 (a) is a tracing of a micrograph of the stretching area of the sample traced from the planar direction. Figure 8 (b) is a tracing of a high-magnification micrograph of the stretching area of the sample traced from the planar direction. Figure 8 (c) is a tracing of a high-magnification micrograph of the stretching area of the sample traced from an oblique direction.

[0068] Figure 9 (a) is a top view of an important part of the stretching area. Figure 9 (b) is along Figure 9 (a) Cross-sectional view along line D-D. Figure 9 (c) Cross-sectional view in the worn state. Figure 9 (d) Cross-sectional view in the natural length state.

[0069] Figure 10 (a) is a tracing of a micrograph of the stretching area of the sample traced from the planar direction. Figure 10 (b) is a tracing of a high-magnification micrograph of the stretching area of the sample traced from the planar direction. Figure 10 (c) is a tracing of a high-magnification micrograph of the stretching area of the sample traced from an oblique direction.

[0070] Figure 11 (a) is a top view of an important part of the non-stretching area. Figure 11 (b) is along Figure 11 (a) Cross-sectional view along line D-D. Figure 11 (c) Cross-sectional view in the worn state. Figure 11 (d) Cross-sectional view in the natural length state.

[0071] Figure 12 is a tracing of a photograph of the non-stretching area of the sample.

[0072] Figure 13 is an enlarged top view of an important part of the non-stretching area.

[0073] Figure 14 is an explanatory diagram showing the changes caused by the stretching of the elastic film.

[0074] Figure 15 is a top view (outer surface side) of the short-type disposable diaper in the unfolded state.

[0075] Figure 16 (a) is along Figure 15 Cross-sectional view along line C-C. Figure 16 (b) is along Figure 15 Cross-sectional view along line E-E.

[0076] Figure 17 This is a cross-sectional view schematically showing an important part of the outer package that has been extended to a certain extent.

[0077] Figure 18 This is a cross-sectional view schematically showing an important part of the outer package that has been extended to a certain extent.

[0078] Figure 19 The (a) of Figure 19 is a top view photograph of the sheet joint formed in the first welding form,

[0079] Figure 20 This is a schematic diagram of an ultrasonic sealing device.

[0080] Figure 21 is a top view showing various arrangement examples of the sheet joint.

[0081] Figure 22 This is an explanatory diagram showing the relationship between the printed pattern and the finished product.

[0082] Figure 23 This is an explanatory diagram of the lateral contraction of the elastic film. Detailed Description of the Invention

[0083] Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings. And, the dotted portions in the cross-sectional view represent joining means such as hot melt adhesives.

[0084] Figures 1 - 6 A short-type disposable diaper is shown. This short-type disposable diaper (hereinafter, simply referred to as a diaper) has: an outer package 20 that constitutes a front body part F and a back body part B; and an inner package 10 that is fixed to the inner surface of the outer package 20 to be integrated. The inner package 10 is formed by sandwiching an absorbent body 13 between a liquid-permeable top sheet 11 and a liquid-impermeable sheet 12. During manufacturing, after joining the back surface of the inner package 10 to the inner surface (upper surface) of the outer package 20 by joining means such as hot melt adhesives, the inner package 10 and the outer package 20 are folded at the boundary between the front body part F and the back body part B, that is, at the center in the front-back direction (longitudinal direction), and their both side portions are joined together by heat welding or hot melt adhesives or the like to form side seal portions 21, thereby becoming a short-type disposable diaper having a waist opening and a pair of left and right leg openings.

[0085] (Structural Example of Inner Package)

[0086] As Figures 4 - 6As shown, the inner package 10 has a structure in which the absorber 13 is interposed between the liquid-permeable topsheet 11 and the liquid-impermeable sheet 12 made of polyethylene or the like, and absorbs and holds the excreted liquid that has passed through the topsheet 11. The planar shape of the inner package 10 is not particularly limited, but is generally set to be substantially rectangular as shown in Figure 1 .

[0087] As the liquid-permeable topsheet 11 covering the front side (skin side) of the absorber 13, a perforated or non-perforated non-woven fabric, or a porous plastic sheet, etc. are preferably used. As the fabric fibers constituting the non-woven fabric, in addition to synthetic fibers such as olefin-based, polyester-based, and polyamide-based fibers such as polyethylene or polypropylene, regenerated fibers such as rayon or cuprammonium fiber, and natural fibers such as cotton can also be used, so that non-woven fabrics obtained by appropriate processing methods such as hydroentangling, spunbonding, hot rolling, meltblowing, and needling can be used. Among these processing methods, the hydroentangling method is excellent in terms of flexibility and drapability, and the hot rolling method is excellent in terms of bulkiness and softness. When a plurality of through-holes are formed in the liquid-permeable topsheet 11, urine and the like are quickly absorbed, resulting in excellent dryness. The liquid-permeable topsheet 11 wraps the side edge portion of the absorber 13 and extends to the back side of the absorber 13.

[0088] Regarding the liquid-impermeable sheet 12 covering the back side (non-skin contact side) of the absorber 13, although a liquid-impermeable plastic sheet such as polyethylene or polypropylene can be used, in recent years, a sheet having moisture permeability is preferably used from the viewpoint of preventing stuffiness. This water-blocking / moisture-permeable sheet is a microporous sheet obtained by melt-kneading an inorganic filler in an olefin resin such as polyethylene or polypropylene to form a sheet and then stretching it in a uniaxial or biaxial direction.

[0089] As the absorber 13, known materials can be used. For example, a material made of an aggregate of pulp fibers, an aggregate of filaments such as cellulose acetate, or a non-woven fabric as the main body, and mixed and fixed with a superabsorbent polymer as needed can be used. Considering the shape and the retention of the polymer, etc., the absorber 13 can be packaged with a packaging sheet 14 having liquid permeability and liquid retention properties such as crepe paper as needed.

[0090] The shape of the absorber 13 is formed into a substantially hourglass shape having a narrowed portion 13N with a width narrower than the front and rear sides in the crotch portion. The size of the narrowed portion 13N can be appropriately determined. The length of the narrowed portion 13N in the front-rear direction can be set to about 20 to 50% of the total length of the diaper, and the width of the narrowest portion thereof can be set to about 40 to 60% of the total width of the absorber 13. In the case of having such a narrowed portion 13N, if the planar shape of the inner package 10 is formed into a substantially rectangular shape, a non-absorber side portion 17 without the absorber 13 is formed in the portion of the inner package 10 corresponding to the narrowed portion 13N of the absorber 13.

[0091] Three-dimensional pleated portions 90 are formed on both sides of the inner body 10 to fit the leg circumference. Figure 5 and Figure 6 As shown, the three-dimensional pleated portion 90 has: a fixed portion 91 fixed to the side portion of the back side of the inner body 10; a main body portion 92 extending from the fixed portion 91 through the side of the inner body 10 and to the side portion of the front side of the inner body 10; a collapsed portion 93 formed by fixing the front and rear ends of the main body 92 to the side portion of the front side of the inner body in a collapsed state; and a free portion 94 formed by not fixing the collapsed portion 93. The above-mentioned parts are formed by a pleated sheet 95 formed as a double-layer sheet by folding back a sheet such as a non-woven fabric. The pleated sheet 95 is installed in the entire front-to-back direction range of the inner body 10, and the collapsed portion 93 is set at a position closer to the front and rear sides than the non-absorbent side portion 17, and the free portion 94 extends to both the front and rear sides of the non-absorbent side portion 17.

[0092] In addition, between the double-layered pleated sheets 95, a slender pleated elastic member 96 is provided at the end of the free portion. The pleated elastic member 96 is used for the following purposes: in the product state, such as Figure 5 As shown, the free portion 94 is erected by elastic contraction force to form a three-dimensional pleated portion 90.

[0093] The liquid-impermeable sheet 12 is folded back to the back side together with the liquid-permeable top sheet 11 on both sides in the width direction of the absorbent body 13. As the liquid-impermeable sheet 12, it is desirable to use an opaque sheet so as not to show the brown color of stool or urine. As the opaque sheet, it is preferable to use a sheet made by adding pigments or fillers such as calcium carbonate, titanium oxide, zinc oxide, white carbon, clay, talc, barium sulfate, etc. to plastic and forming it into a film.

[0094] As the pleat elastic member 96, materials such as styrene rubber, olefin rubber, polyurethane rubber, ester rubber, polyurethane, polyethylene, polystyrene, styrene butadiene polymer, silicon, polyester, etc., which are commonly used, can be used. In addition, in order to prevent it from being easily seen from the outside, it is suitable to be arranged with a thickness of 925 dtex or less, a tension of 150 to 350%, and an interval of 7.0 mm or less. In addition, as the pleat elastic member 96, in addition to the linear form as shown in the figure, a belt with a certain degree of width can also be used.

[0095] The fabric fibers constituting the aforementioned pleated sheet 95 are the same as those of the liquid-permeable topsheet 11. In addition to synthetic fibers such as olefins, polyesters, and amides such as polyethylene or polypropylene, regenerated fibers such as rayon or cuprammonium fiber, and natural fibers such as cotton can also be used. Thus, non-woven fabrics obtained by appropriate processing methods such as spunbonding, hot rolling, meltblowing, and needling can be used. In particular, in order to prevent stuffiness and dampness, non-woven fabrics with excellent air permeability by suppressing the basis weight are suitable. Moreover, regarding the pleated sheet 95, in order to prevent urine and the like from passing through, and in order to prevent rashes and improve the skin feel (dryness), a water-repellent treated non-woven fabric coated with a water-repellent agent such as a silicone-based, paraffin metal-based, or alkyl chromic chloride-based agent is preferably used.

[0096] As Figure 3 shown, the back surface of the inner package 10 is fixed to the inner surface of the outer package 20 in the inner and outer fixing regions 10B (hatched regions) by a hot melt adhesive or the like. The inner and outer fixing regions 10B extend along the front and back sides of the absorber-free side portions 17 with a width extending from one absorber-free side portion 17 to the other absorber-free side portion 17. The side edges of the inner and outer fixing regions 10B are preferably located at positions closer to the side than the middle in the width direction of the absorber-free side portion 17. In particular, it is more preferably fixed to the outer package 20 over almost the entire width direction and almost the entire front and back directions of the inner package 10.

[0097] (Front and back pressing sheets)

[0098] Also as Figure 1 and Figure 4 shown, in order to cover the front and rear end portions of the inner package 10 mounted on the inner surface of the outer package 20 and prevent leakage from the front and rear edges of the inner package 10, front and back pressing sheets 50 and 60 can be provided. To explain the illustrated embodiment in more detail, the front pressing sheet 50 extends over the entire width direction within the range from the inner surface of the folded-back portion 20C of the waist end portion region 23 to the position coinciding with the front end portion of the inner package 10 on the inner surface of the outer package 20 in the front body portion F, and the back pressing sheet 60 extends over the entire width direction within the range from the inner surface of the folded-back portion 20C of the waist end portion region 23 to the position coinciding with the rear end portion of the inner package 10 on the inner surface of the outer package 20 in the back body portion B. If a small non-bonding portion is provided over the entire width direction (or only the central portion) at the crotch side edges of the front and back pressing sheets 50 and 60, not only can the adhesive overflow be prevented, but also this portion can slightly float up from the topsheet and function as a leak-proof wall.

[0099] If the front and rear pressing pieces 50 and 60 are installed separately as shown in the figure, there is an advantage of increasing the freedom of fabric selection, but there are also disadvantages such as an increase in materials or manufacturing processes. Therefore, the folded portion 20C formed by folding the outer body 20 toward the inner surface of the diaper can be extended to the portion overlapping with the inner body 10 to form a portion equivalent to the above-mentioned pressing pieces 50 and 60.

[0100] (Example of the structure of the outer casing)

[0101] The outer body 20 extends to a position laterally than the side edge of the absorbent body 13. Regarding the outer body 20, the side edge of the outer body 20 may be located at a position closer to the center in the width direction than the side edge of the inner body 10 in the crotch portion as shown in the illustrated form, or the side edge of the outer body 20 may be located at a position closer to the outside in the width direction than the side edge of the inner body 10 in the crotch portion. In addition, the outer body 20 has: a waist portion T, which is a front-to-back direction range corresponding to the side seal portion 21; and a middle portion L, which is a front-to-back direction range between the waist portion T of the front body portion F and the waist portion T of the back body portion B. Furthermore, in the outer body 20 in the illustrated form, except for the middle of the middle portion L in the front-to-back direction, as shown in the figure Figure 2 and Figures 4 - 6 As shown, an elastic film 30 is stacked between the first sheet 20A and the second sheet 20B, and as shown in FIG. Figure 7 As shown, there is an elastic film stretch structure 20X in which the stretch direction is set to the width direction as follows: the first sheet 20A and the second sheet 20B are joined together at a plurality of sheet joints 40 arranged at intervals through the through holes 31 penetrating the elastic film 30. The first sheet 20A and the second sheet 20B may be joined together indirectly via the elastic film 30 instead of through the through holes 31 of the elastic film 30. The planar shape of the outer body 20 is formed by the concave leg circumference 29 in such a way that the two side edges in the width direction of the middle part L respectively form leg openings, and the outer body 20 is formed into an hourglass-like shape as a whole. The outer body 20 may be configured such that the outer body 20 is formed separately at the front body part F and the back body part B, and the two are separated in the front-back direction at the crotch part.

[0102] Figure 1 and Figure 2 The embodiment shown is the embodiment in which the elastic film stretch structure 20X extends to the waist end region 23. However, if the elastic film stretch structure 20X is used in the waist end region 23, the fastening of the waist end region 23 becomes insufficient. Therefore, it is also possible to Figure 15 and Figure 16As shown, instead of providing the elastic film expansion and contraction structure 20X in the waist end region 23, an existing expansion and contraction structure based on the elongated waist elastic member 24 is provided. However, in the edge portion of the leg opening in the outer body 20, no elongated elastic expansion and contraction member extending along the leg opening is provided. The waist elastic member 24 is a plurality of elongated elastic members such as rubber threads arranged at intervals in the front-rear direction, and provides an expansion and contraction force in a manner of fastening the waist circumference of the body. Regarding the waist elastic member 24, instead of making the intervals close and substantially arranged in a bundle, more than 3, preferably more than 5, are arranged at intervals of about 3 to 8 mm in a manner of forming a specified expansion and contraction region. The elongation rate at the time of fixing the waist elastic member 24 can be appropriately determined, but in the case of ordinary adult use, it can be set to about 230 to 320%. The waist elastic member 24 uses rubber threads in the illustrated example, but other elongated expansion and contraction members such as flat rubber can also be used.

[0103] As another form, although not shown, appropriate deformations such as the following can also be made: a form in which the elastic film expansion and contraction structure 20X is not provided in the intermediate portion L between the waist portion T of the front body portion F and the waist portion T of the rear body portion B, or a form in which the expansion and contraction structure 20X is continuously provided in the front-rear direction from within the waist portion T of the front body portion F through the intermediate portion L to the waist portion T of the rear body portion B, or the elastic film expansion and contraction structure 20X is provided only in any one of the front body portion F and the rear body portion B.

[0104] Regarding the shape of each sheet joint portion 40 and the through hole 31 in the natural length state, it can be appropriately determined, and it can be set to a perfect circle (refer to Figure 7 , Figure 8 ), oval, triangle, rectangle (refer to Figures 9 - 12 ), polygon such as rhombus (refer to Figure 13 (b)), or convex lens shape (refer to Figure 13 (a)), concave lens shape (refer to Figure 13 (c)), star shape, cloud shape, or any other shape. The size of each sheet joint portion is not particularly limited. Regarding the maximum length, it is preferably set to 0.5 to 3.0 mm, particularly preferably set to 0.7 to 1.1 mm. Regarding the maximum width 40x, it is preferably set to 0.1 to 3.0 mm, and particularly in the case of a shape that is longer in the direction perpendicular to the expansion and contraction direction, it is preferably set to 0.1 to 1.1 mm.

[0105] Regarding the size of each sheet joint portion 40, it can be appropriately determined. However, if it is too large, the influence of the hardness of the sheet joint portion 40 on the touch becomes large. If it is too small, the bonding area decreases and the materials cannot be sufficiently bonded to each other. Therefore, in general, it is preferable to set the area of each sheet joint portion 40 to about 0.14 to 3.5 mm2 Regarding the area of the opening of each through-hole 31, since the sheet joint portion is formed through the through-hole 31, it suffices to be above the sheet joint portion, but it is preferably set to about 1 to 1.5 times the area of the sheet joint portion. Moreover, the area of the opening of the through-hole 31 does not refer to the value in the state of the elastic film 30 alone, but refers to the value in the state integrated with the first sheet layer 20A and the second sheet layer 20B and in the natural length state. When the area of the opening of the through-hole 31 is different between the front and back surfaces of the elastic film 30 or is uneven in the thickness direction, etc., the area of the opening of the through-hole 31 refers to the minimum value.

[0106] Regarding the planar arrangement of the sheet joint portion 40 and the through-hole 31, it can be appropriately determined, but a regularly repeated planar arrangement is preferred. In addition to being regularly repeated like the rhombic lattice shape shown in (a) of Figure 21 or the hexagonal lattice shape shown in (b) of Figure 21 (these are also called staggered shapes), the square lattice shape shown in (c) of Figure 21 , the rectangular lattice shape shown in (d) of Figure 21 , the parallelepiped lattice shape shown in (e) of Figure 21 (as shown in the figure, a group of multiple parallel oblique columns are arranged in two groups in a mutually intersecting manner), etc. (including shapes in which these groups of oblique columns are inclined at an angle less than 90 degrees with respect to the stretching direction), in addition to these, the groups of the sheet joint portion 40 (the arrangement of the group units can be regular or irregular, and can also be in the form of patterns or characters, etc.) can be regularly repeated.

[0107] When the first sheet layer 20A and the second sheet layer 20B in the sheet joint portion 40 are joined through the through-hole 31 formed in the elastic film 30, it is desirable that the first sheet layer 20A and the second sheet layer 20B are not joined to the elastic film 30 at least outside the first sheet layer 20A and the second sheet layer 20B in the sheet joint portion 40.

[0108] The joining means of the first sheet layer 20A and the second sheet layer 20B in the sheet joint portion 40 is not particularly limited. For example, the joining of the first sheet layer 20A and the second sheet layer 20B in the sheet joint portion 40 can be performed by a hot melt adhesive, or can be performed by joining means based on material welding such as heat sealing or ultrasonic sealing.

[0109] When the first sheet layer 20A and the second sheet layer 20B are joined through the through-hole 31 of the elastic film 30 in the sheet joint portion 40, the form of forming the sheet joint portion 40 by material welding can be any of the following forms, but the second and third welding forms are preferred: the first welding form (refer to Figure 17(a)), wherein the first sheet layer 20A and the second sheet layer 20B are joined together only by the molten solidified product 20m of most or a part of at least one of the first sheet layer 20A and the second sheet layer 20B in the sheet joint portion 40; the second welding form (see Figure 17 (b)), wherein the first sheet layer 20A and the second sheet layer 20B are joined together only by the molten solidified product 30m of all or most or a part of the elastic film 30 in the sheet joint portion 40; and the third welding form (see Figure 17 (c)) which is a combination of the first welding form and the second welding form. Particularly preferably, the first sheet layer 20A and the second sheet layer 20B are joined together by the molten solidified product 20m of a part of the first sheet layer 20A and the second sheet layer 20B and the molten solidified product 30m of all or most of the elastic film 30 in the sheet joint portion 40. And, in Figure 19 (b) of the third welding form shown, between the fiber molten solidified products 20m of the first sheet layer 20A or the second sheet layer 20B that appear black, the molten solidified product 30m of the elastic film 30 that appears white can be seen. In contrast, in Figure 19 (a) of the first welding form shown, the molten solidified product of the elastic film (the white part is the boundary of the fiber molten solidified product 20m and the diffuse reflection of the fiber molten solidified product 20m) cannot be seen between the fiber molten solidified products 20m of the first sheet layer 20A or the second sheet layer 20B.

[0110] In the case of joining the first sheet layer 20A and the second sheet layer 20B using the molten solidified product 20m of most or a part of at least one of the first sheet layer 20A and the second sheet layer 20B as an adhesive as in the first bonding form or the third bonding form, it is preferable that a part of the first sheet layer 20A and the second sheet layer 20B does not melt, so that the sheet joint portion 40 does not harden. And, when the first sheet layer 20A and the second sheet layer 20B are non-woven fabrics, the part of the first sheet layer 20A and the second sheet layer 20B that does not melt includes the following forms: for all the fibers of the sheet joint portion 40, the core (including not only the core in the composite fiber but also the central part of the single-component fiber) remains, but the surrounding part (including not only the sheath in the composite fiber but also the surface layer side part of the single-component fiber) melts; or, a part of the fibers does not melt at all but the remaining fibers all melt, or the core remains but the surrounding part melts.

[0111] When joining the first layer 20A and the second layer 20B using the melt-cured product 30m of the elastic film 30 as an adhesive, as in the second welding form and the third welding form, the peel strength is high. In the second welding form, it can be manufactured by the following method: Under the condition that the melting point of at least one of the first layer 20A and the second layer 20B is higher than the melting point of the elastic film 30 and the heating temperature when the sheet joint 40 is formed, the elastic film 30 is sandwiched between the first layer 20A and the second layer 20B, and the portion that becomes the sheet joint 40 is pressurized / heated to melt only the elastic film 30. On the other hand, in the third welding form, it can be manufactured by the following method: Under the condition that the melting point of at least one of the first layer 20A and the second layer 20B is higher than the melting point of the elastic film 30, the elastic film 30 is sandwiched between the first layer 20A and the second layer 20B, and the portion that becomes the sheet joint 40 is pressurized / heated to melt at least one of the first layer 20A and the second layer 20B and the elastic film 30. From this perspective, the melting point of the elastic film 30 is preferably about 80 - 145 °C, the melting points of the first layer 20A and the second layer 20B are preferably about 85 - 190 °C, particularly preferably about 150 - 190 °C, and the difference between the melting points of the first layer 20A and the second layer 20B and the melting point of the elastic film 30 is preferably about 60 - 90 °C. Additionally, the heating temperature is preferably about 100 - 150 °C.

[0112] In the second welding form and the third welding form, when the first layer 20A and the second layer 20B are non-woven fabrics, the melt-cured product 30m of the elastic film 30 can Figure 18 as shown in (c) of Figure 17 penetrate between the fibers throughout the entire thickness direction of the first layer 20A and the second layer 20B in the sheet joint 40, however, in the form where it penetrates to the middle of the thickness direction between the fibers as shown in (b) of Figure 17 of Figure 18 or in the form where it hardly penetrates between the fibers of the first layer 20A and the second layer 20B as shown in (a) of Figure 18 or in the form where it hardly penetrates between the fibers of the first layer 20A and the second layer 20B as shown in (b) of

[0113] Figure 20 the flexibility of the sheet joint 40 is high.An example of an ultrasonic sealing device suitable for forming a second welding form and a third welding form is shown. In this ultrasonic sealing device, when forming the sheet joint portion 40, the first sheet layer 20A, the elastic film 30, and the second sheet layer 20B are fed between the support roller 60 and the ultrasonic horn 61, where the support roller 60 has protrusions 60a formed on its outer surface according to the pattern of the sheet joint portion 40. At this time, for example, by making the feeding and conveying speed of the elastic film 30 based on the feeding drive roller 63 and the pinch roller 62 upstream slower than the conveying speed after the support roller 60 and the ultrasonic horn 61, thus, on the path from the clamping position based on the feeding drive roller 63 and the pinch roller 62 to the sealing position based on the support roller 60 and the ultrasonic horn 61, the elastic film 30 is stretched in the MD direction (machine direction, conveying direction) to a specified elongation rate. Regarding the elongation rate of this elastic film 30, it can be set by selecting the speed difference between the support roller 60 and the feeding drive roller 63, and for example, it can be set to approximately 300% - 500%. 62 is a pinch roller. The first sheet layer 20A, the elastic film 30, and the second sheet layer 20B fed between the support roller 60 and the ultrasonic horn 61 are heated by the ultrasonic vibration energy of the ultrasonic horn 61 while being pressed between the protrusions 60a and the ultrasonic horn 61 in the state of being laminated in this order, and only the elastic film 30 is melted, or at least one of the first sheet layer 20A and the second sheet layer 20B and the elastic film 30 are melted, thereby forming through-holes 31 in the elastic film 30. At the same time, the first sheet layer 20A and the second sheet layer 20B are joined together through these through-holes 31. Therefore, in this case, by selecting the size, shape, separation interval, the pattern of the roller length direction and the roller circumferential direction of the protrusions 60a of the support roller 60, etc., the area ratio of the sheet joint portion 40 can be selected.

[0114] Regarding the reason for forming the through-holes 31, although it is not necessarily clear, it can be considered that: the part of the elastic film 30 corresponding to the protrusions 60a of the support roller 60 melts and detaches from the surroundings, thereby forming holes. At this time, as shown in (a) of Figure 7 , (a) of Figure 9 , and (a) of Figure 11 , the part between adjacent through-holes 31 arranged in the stretching direction in the elastic film 30 is cut off from the parts on both sides in the stretching direction by the through-holes 31 and loses the support on both sides in the contraction direction. Therefore, within the range where the continuity in the direction perpendicular to the contraction direction can be maintained, the closer to the center side in the direction perpendicular to the stretching direction, the more it contracts toward the center side in the stretching direction until it reaches equilibrium, and thus the through-holes 31 expand in the stretching direction. Then, if the sheet joint portion 40 is formed in a pattern such as the stretching region 80 described later, which leaves a part where the elastic film 30 is linearly continuous along the stretching direction, as shown in (a) of Figure 7 and (a) of Figure 9As shown in (a) of Figure 11 , when shrinking to the natural length state by cutting into individual products, etc., the length of the enlarged portion of the through-hole 31 in the stretching direction shrinks until there is no gap between the through-hole 31 and the sheet joint portion 40. On the other hand, if the sheet joint portion 40 is formed with a pattern where there is no portion where the elastic film 30 is linearly continuous along the stretching direction as in the non-stretching region 70 described later, as shown in (a) of

[0115] Regarding the components of the first sheet layer 20A and the second sheet layer 20B, as long as they are sheet-like and the design drawing printing portion of the elastic film described later can be observed from the outside, they can be used without particular limitation. However, from the viewpoints of air permeability and softness, non-woven fabric is preferably used. There is no particular limitation on what kind of raw material fiber the non-woven fabric is. For example, olefin-based such as polyethylene or polypropylene, synthetic fibers such as polyester-based and polyamide-based, regenerated fibers such as rayon or cuprammonium rayon, natural fibers such as cotton, etc., or mixed fibers or composite fibers using two or more of them can be exemplified. In addition, the non-woven fabric can be manufactured by any processing. As the processing method, known methods such as hydroentangling method, spunbond method, hot rolling method, meltblown method, needling method, hot air method, dot bonding method, etc. can be exemplified. When using non-woven fabric, the weight per unit area is preferably about 12 - 20 g / m 2 . In addition, a part or all of the first sheet layer 20A and the second sheet layer 20B can be a pair of layers formed by folding back and opposing a single sheet of material. For example, as shown in the illustrated form, in the waist end region 23, the component on the outside is used as the second sheet layer 20B, and the folded-back portion 20C folded inwardly at the waist opening edge is used as the first sheet layer 20A, with the elastic film 30 interposed therebetween. And, in the portion other than the waist end region 23, the component on the inside is used as the first sheet layer 20A, and the component on the outside is used as the second sheet layer 20B, with the elastic film 30 interposed therebetween. Of course, it can also be that the components of the first sheet layer 20A and the second sheet layer 20B are separately provided throughout the front-back direction without folding back the components, and the elastic film 30 is interposed between the components of the first sheet layer 20A and the second sheet layer 20B.

[0116] The elastic film 30 is not particularly limited as long as it is a thermoplastic resin film having elasticity by itself. In addition to the non-porous film, in order to allow air permeability, a film formed with a plurality of holes or slits may also be used. Particularly preferably, the elastic film 30 is such that the tensile strength in the width direction (the stretching direction, the MD direction) is 8 to 25 N / 35 mm, the tensile strength in the front-rear direction (the direction perpendicular to the stretching direction, the CD direction) is 5 to 20 N / 35 mm, the tensile elongation in the width direction is 450 to 1050%, and the tensile elongation in the front-rear direction is 450 to 1400%. The thickness of the elastic film 30 is not particularly limited, but is preferably about 20 to 40 μm.

[0117] (Stretching area)

[0118] The area of the outer package 20 having the elastic film stretching structure 20X has a stretching area capable of stretching in the width direction. In the stretching area 80, there is a portion 32 where the elastic film 30 is linearly continuous along the width direction, and it contracts in the width direction by the contraction force of the elastic film 30 and can be elongated in the width direction. More specifically, in a state where the elastic film 30 is elongated in the width direction, the first layer 20A and the second layer 20B are joined via the through holes 31 of the elastic film 30 at intervals in the width direction and in the front-rear direction (the direction perpendicular to the stretching direction) perpendicular to the width direction, respectively, to form a plurality of sheet joining portions 40, thereby forming the elastic film stretching structure 20X. And by arranging the through holes 31 in the stretching area 80 in such a way that there is a portion where the elastic film 30 is linearly continuous along the width direction, such stretchability can be imparted.

[0119] In the stretching area 80, in the natural length state, as Figure 7 shown in (d) of Figure 9 and Figure 7 shown in (d) of Figure 9 , the first layer 20A and the second layer 20B between the sheet joining portions 40 bulge in the direction of separation from each other, forming the contraction wrinkles 25 extending in the front-rear direction. As Figure 7 shown in (c) of Figure 9 and Figure 7 shown in (c) of Figure 9As can also be seen from (a) and (b) thereof, in these states, a gap is formed between the through-hole 31 on the elastic film 30 and the sheet joint portion 40. Even if the material of the elastic film 30 is a non-porous film or sheet, breathability can be provided through this gap. In addition, in Figure 7 the (d) of Figure 9 In the natural length state shown in the (d) of, the through-hole 31 is narrowed due to the shrinkage of the elastic film 30, and almost no gap is formed between the through-hole 31 and the sheet joint portion 40. Also, the states of the shrinkage wrinkles 25 in the worn state and the natural length state are also shown in Figure 8 and Figure 10 .

[0120] It is desirable to set the elastic limit elongation rate of the stretchable region 80 in the width direction to 200% or more (preferably 265 - 295%). The elastic limit elongation rate of the stretchable region 80 is roughly determined by the elongation rate of the elastic film 30 during manufacturing. However, based on this, it will decrease due to reasons that hinder the contraction in the width direction. Such hindering reasons are mainly the ratio of the length 40x of the sheet joint portion 40 in each unit length in the width direction. The larger this ratio, the more the elastic limit elongation rate decreases. Usually, the length 40x of the sheet joint portion 40 is related to the area ratio of the sheet joint portion 40. Therefore, the elastic limit elongation rate of the stretchable region 80 can be adjusted by the area ratio of the sheet joint portion 40.

[0121] The elongation stress of the stretchable region 80 can be mainly adjusted by the sum of the widths 32w of the portions 32 where the elastic film 30 is linearly continuous in the width direction. The width 32w of the portion 32 where the elastic film 30 is linearly continuous in the width direction is equal to the interval 31d in the front-rear direction of the through-holes 31 that are adjacent to both side edges of the continuous portion 32. When the length 31y of the through-hole 31 in the front-rear direction is equal to the length 40y of the sheet joint portion 40 in the front-rear direction (such as in the case of using a method of simultaneously forming the aforementioned through-hole 31 and sheet joint portion 40), the interval 31d of the through-hole 31 is equal to the interval 40d in the front-rear direction of the sheet joint portion 40 that is adjacent to both side edges of the continuous portion. Therefore, in this case, the elongation stress of the stretchable region 80 can be adjusted by the ratio of the length 40y of the sheet joint portion 40 in each unit length in the front-rear direction. Usually, since the length 40y of the sheet joint portion 40 is related to the area ratio of the sheet joint portion 40, the elongation stress of the stretchable region 80 can be adjusted by the length of the sheet joint portion 40 or the area ratio of the sheet joint portion 40. Regarding the elongation stress of the stretchable region 80, the elongation stress when stretched to 50% of the elastic limit can be used as a reference.

[0122] The area ratio of the sheet joint portion 40 in the stretchable region 80 and the area of each sheet joint portion 40 can be appropriately determined. However, under normal circumstances, it is preferably set within the following ranges.

[0123] Area of the sheet joint portion 40: 0.14 - 3.5 mm 2 (Particularly preferably 0.14 - 1.0 mm 2 )

[0124] Area ratio of the sheet joint portion 40: 1.8 - 19.1% (Particularly preferably 1.8 - 10.6%)

[0125] In this way, since the elastic limit elongation rate and elongation stress of the stretchable region 80 can be adjusted by the area of the sheet joint portion 40, as Figure 15 shown, multiple regions with different area ratios of the sheet joint portion 40 can be provided within the stretchable region 80, and the fit can be changed according to the location. In the Figure 15 form shown, in the region 81 extending obliquely along the crotch in the front body part F and the edge region 82 of the leg opening, the area ratio of the sheet joint portion 40 is higher than that of other regions, so the elongation stress is weaker, and it becomes a region that stretches and contracts softly. In addition, in the iliac opposing region 83 in the back body part B and the edge region 82 of the leg opening, the area ratio of the sheet joint portion 40 is also higher than that of other regions, so the elongation stress is weaker, and it becomes a region that stretches and contracts softly.

[0126] (Non - stretchable region)

[0127] In the region of the outer body 20 having the elastic film stretch structure 20X, as Figure 15 shown, a non - stretchable region 70 can be provided on at least one side in the width direction of the stretchable region 80. The arrangement of the stretchable region 80 and the non - stretchable region 70 can be appropriately determined. In the case of the outer body 20 of the short - type disposable diaper as in this embodiment, the portion overlapping with the absorber 13 is a region that does not require stretching. Therefore, it is preferable to use a part or all of the portion overlapping with the absorber 13 (desirably including almost the entire inner and outer fixing regions 10B) as the non - stretchable region 70 as shown in the figure. Of course, the non - stretchable region 70 can also be provided from the region overlapping with the absorber 13 to the region that does not overlap with the absorber 13 in its width direction or front - back direction, or the non - stretchable region 70 can also be provided only in the region that does not overlap with the absorber 13.

[0128] The non-stretchable region 70 is set as a region where, although the elastic film 30 is continuous in the width direction, due to the presence of the through-holes 31, it does not have a portion that is linearly continuous in the width direction. Therefore, even in a state where the elastic film 30 is stretched in the width direction, the first sheet layer 20A and the second sheet layer 20B are joined via the through-holes 31 of the elastic film 30 at intervals in the width direction and in the front-rear direction perpendicular to the width direction, respectively, to form a plurality of sheet joints 40, thereby forming the entire elastic film stretch structure 20X including both the stretchable region 80 and the non-stretchable region 70. However, as Figure 11 shown, in the non-stretchable region 70, since the elastic film 30 is not linearly continuous in the width direction, the contraction force of the elastic film 30 hardly acts on the first sheet layer 20A and the second sheet layer 20B, and the stretchability almost disappears, and the elastic limit elongation rate approaches 100%. And, in such a non-stretchable region 70, the first sheet layer 20A and the second sheet layer 20B are joined together at a plurality of sheet joints 40 arranged at intervals, and the sheet joints 40 are not continuous, so a decrease in flexibility is prevented. In other words, the stretchable region 80 and the non-stretchable region 70 can be formed by whether there is a portion where the elastic film 30 is not linearly continuous in the width direction. In addition, the continuity of the elastic film 30 remains in the non-stretchable region 70. According to Figure 12 it can also be known that neither an independent cut piece of the elastic film 30 remains, nor are wrinkles formed, so the aesthetics are very good, and the breathability in the thickness direction based on the through-holes 31 is ensured. In the non-stretchable region 70, it is preferable that the elastic limit elongation rate in the width direction is 120% or less (preferably 110% or less, more preferably 100%).

[0129] The arrangement pattern of the through-holes 31 on the elastic film 30 in the non-stretchable region 70 can be appropriately determined. However, if it is set in a staggered configuration as Figure 11 shown, and the pattern is set such that the center interval 31e of the through-holes 31 in the front-rear direction is shorter than the length 31y of the through-holes 31 in the front-rear direction, then while maintaining the continuity of the elastic film 30, the linear continuity in the width direction can be almost completely eliminated, and the aesthetics are also as Figure 12 shown and become preferable. In this case, it is preferable that the center interval 31f of the through-holes 31 in the width direction is shorter than the length 31x of the through-holes 31 in the width direction.

[0130] Under normal circumstances, especially when the elongation stress is 4 to 12 N / 35 mm when the elastic film 30 is stretched 4 times in the width direction, in a state where the non-stretchable region 70 is stretched to the elastic limit in the width direction, the center interval 31e of the through-holes 31 in the front-rear direction is preferably 0.4 to 2.7 mm, and the length 31y of the through-holes 31 in the front-rear direction is preferably 0.5 to 3.0 mm, particularly preferably 0.7 to 1.1 mm. Additionally, the center interval 31f of the through-holes 31 in the width direction is preferably 0.5 to 2 times the length 31y of the through-holes 31 in the front-rear direction, particularly preferably 1 to 1.2 times, and the length 31x of the through-holes 31 in the width direction is preferably 1.1 to 1.8 times the center interval 31f of the through-holes 31 in the width direction, particularly preferably 1.1 to 1.4 times. And, in a state where the non-stretchable region 70 is stretched to the elastic limit in the width direction (in other words, in a state where the first sheet layer 20A and the second sheet layer 20B are fully unfolded), the center interval 31f of the through-holes 31 in the width direction is equal to the center interval 40f of the sheet joint portion 40 in the width direction, the center interval 31e of the through-holes 31 in the front-rear direction is equal to the center interval 40e of the sheet joint portion 40 in the front-rear direction, and the length 31y of the through-holes 31 in the front-rear direction is equal to the length 40y of the sheet joint portion 40 in the front-rear direction.

[0131] In the non-stretchable region 70, if the first sheet layer 20A and the second sheet layer 20B are not joined to the elastic film 30 except between the first sheet layer 20A and the second sheet layer 20B in the sheet joint portion 40, and in the natural length state, gaps are formed on both sides in the width direction of the sheet joint portion 40 by separating the peripheral edges of the through-holes 31 of the elastic film 30 from the sheet joint portion 40, then even if the material of the elastic film 30 is a non-porous film or sheet, air permeability can always be provided through these gaps, so it is preferred. In the case of adopting a method of simultaneously forming the aforementioned through-holes 31 and the sheet joint portion 40, this state is naturally achieved regardless of the shape of the sheet joint portion 40 or the like.

[0132] The shapes of the respective sheet joint portions 40 and the through-holes 31 in the natural length state are not particularly limited, but from the perspective of flexibility, a smaller area is desired, and in order to eliminate the linear continuity of the elastic film 30 in the width direction, a shape that is longer in the front-rear direction is desired. Therefore, it is preferably set as an ellipse, rectangle (refer to Figure 11 , Figure 13 's (d)), rhombus (refer to Figure 13 's (b)), convex lens shape (refer to Figure 13 's (a)), concave lens shape (refer to Figure 13(c)). However, if the angle is made acute like a rhombus, the elastic film 30 is likely to break. In contrast, when it is in the shape of a convex lens, the welding of the sheet joint portion 40 is stable, so it is preferable. The concave lens shape is preferable in that the area can be further reduced.

[0133] The area ratio of the sheet joint portion 40 in the non-stretchable region and the area of each sheet joint portion 40 can be appropriately determined. However, in general, if set within the following ranges, the area of each sheet joint portion 40 is small and the area ratio of the sheet joint portion 40 is low. As a result, the non-stretchable region 70 does not become hard, so it is preferable.

[0134] Area of the sheet joint portion 40: 0.10 - 0.75 mm 2 (Particularly preferably 0.10 - 0.35 mm 2 )

[0135] Area ratio of the sheet joint portion 40: 4 - 13% (particularly preferably 5 - 10%)

[0136] In this way, the elastic limit elongation rate of the non-stretchable region 70 can be changed by the arrangement pattern of the through holes 31, or the size and center interval of each through hole 31. Therefore, although not shown, these factors can also be made different at multiple parts within the stretchable region 80 or between multiple non-stretchable regions 70. For example, it is a preferable method to make the elastic limit elongation rate in the non-stretchable region 70 of the front body part F larger than that in the non-stretchable region 70 of the back body part B.

[0137] Although the non-stretchable region 70 has a linearly continuous portion in the width direction like the stretchable region, the area ratio of the sheet joint portion is higher than that of the stretchable region. As a result, the elastic limit elongation rate is relatively significant. Specifically, methods such as setting it to 130% or less, or cutting it at one or more positions in the width direction like the conventional stretchable structure using rubber threads to eliminate other stretchability can be adopted.

[0138] (Design drawing printing section)

[0139] Characterized in that, as Figure 2 、 Figure 14 and Figure 15As shown in the figure, a design drawing printing section 33 is provided on a portion of the elastic film 30 located in the stretching region 80. Since the elastic film 30 does not form wrinkles or pleats due to stretching, deformation of the design drawing caused by the formation of wrinkles or pleats on the printing object of the design drawing does not occur. In addition, in addition to the advantage of having no impact on the stretchability of the stretching region 80 at all, there are also the following advantages: compared with non-woven fabric, the surface of the elastic film 30 is excellent in printing applicability; and since the printing surface of the elastic film 30 is covered by the first layer 20A and the second layer 20B, printing is difficult to peel off.

[0140] In order to provide the design drawing printing section 33 on the elastic film 30, during manufacturing, an elastic film 30 pre-printed with the design drawing printing section 33 on the portion that becomes the stretching region 80 can be used, or alternatively, before the elastic film 30 is stretched (on the upstream side of the feeding drive roller 63 and the pinch roller 62 in the Figure 20 manufacturing method), the design drawing printing section 33 can be printed on the portion of the elastic film 30 that becomes the stretching region 80 on the production line. The printing method can be letterpress printing, intaglio printing, offset printing, inkjet printing, etc., and is not particularly limited. In order to improve the printing applicability of the elastic film 30, it is desirable to perform corona treatment on the printing surface.

[0141] The design drawing of the design drawing printing section 30 is not particularly limited. For example, it can be a pattern for decoration (including other patterns such as water droplet patterns or patterns, paintings, and single-point pattern figures), display of usage methods or usage aids, dimensions, etc., identification display of manufacturers or product names, characteristic functions, etc., or a combination thereof.

[0142] Regarding the design drawing printing section 33, in addition to being provided on a part of the elastic film 30, it can also be provided throughout the entire elastic film 30. The illustrated method assumes the case where the same pattern design drawing printing section 33 is provided, and it has become a method of providing the design drawing printing section 33 throughout the entire width direction of a part in the front-rear direction, but the design drawing printing section 33 can also be provided only in a part or all of the width direction intermediate part in the front-rear direction, or only on both sides in the width direction. In addition, as Figure 14 shown in (b) of the figure, the design drawing printing section 33 can be provided not only in the stretching region 80 but also in a part or the whole of the non-stretching region 70.

[0143] When the design drawing printing section 33 is provided on the elastic film 30, the design drawing printing section 33 deforms as the elastic film 30 stretches. In this case, as Figure 14As shown in (a) of , as long as the entire design drawing printing section 33 expands and contracts identically, the shape of the design drawing printing section 33 also deforms identically. Therefore, the balance of the entire design drawing printing section 33 is not disrupted. However, the elastic film expansion and contraction structure 20X has the following advantages: By setting a plurality of expansion and contraction regions 80 with different elastic limit expansion rates by making the patterns of the sheet joint portions 40 different, it is possible to change the fit or the expandability / non-expandability according to the location. Such a plurality of regions with different elastic limit expansion rates are formed due to the following factors: After releasing the tension applied to the first sheet layer 20A, the second sheet layer 20B, and the elastic film 30 therebetween by cutting into individual products or parts etc. during the manufacturing process and after forming the sheet joint portions 40, the difference in the contraction recovery amount of the elastic film 30. The contraction recovery amount of the elastic film 30 (including the non-expandable state where it hardly contracts) is lower than the expansion rate of the elastic film 30 that has been elongated before forming the sheet joint portions 40, and the degree of this decrease can be changed by the pattern of the sheet joint portions 40. Therefore, if the design drawing printing section 33 is set identically at the portions of the elastic film 30 that become a plurality of regions, in the natural length state or the worn state, the deformation rate of the design drawing printing section 33 in the expansion and contraction direction is different for each region, resulting in deterioration of the aesthetics.

[0144] For example, currently as Figure 22 shown in (a) of , consider the following situation: There are a region with a small elastic limit expansion rate and a region with a large elastic limit expansion rate. Let the standard dimension 33s of the design drawing printing section 33 in the expansion and contraction direction before the elastic film 30 is elongated be 100, and manufacture it with the expansion rate of the elastic film 30 when forming the sheet joint portions 40 being 200%. Since the dimension 33m of the design drawing printing section 33 in the expansion and contraction direction when forming the sheet joint portions 40 becomes 200, in the natural length state, in the region with a small elastic limit expansion rate, the contraction recovery amount is small. For example, if the contraction recovery amount is set to 20, the dimension 33n of the design drawing printing section 33 in the expansion and contraction direction becomes 180. In the region with a large elastic limit expansion rate, the contraction recovery amount is large. For example, if the contraction recovery amount is set to 80, the dimension 33t of the design drawing printing section 33 in the expansion and contraction direction becomes 120. Thus, the deformation difference of the design drawing printing section 33 in the expansion and contraction direction in the two regions is very different.

[0145] On the contrary, if a deformed design drawing is printed as follows: for a region with a smaller elastic limit elongation rate, that is, a region with a smaller amount of shrinkage recovery after the elastic film 30 is elongated to form the sheet joint portion 40, the deformed design drawing shrinks and deforms in the stretching direction at a higher deformation rate. Then, between the regions, the difference in the deformation rate of the design drawing printing portion 33 in the stretching direction becomes smaller, and deterioration of the appearance can be prevented. Here, the deformation rate is a quantity that represents the ratio of the length difference before and after shrinkage deformation to the length before shrinkage deformation as a percentage. For example, if considered under the same conditions as the specific example shown in (a) of Figure 22 then, as shown in (b) of Figure 22 if a deformed design drawing that shrinks and deforms at a high deformation rate, such as 50%, in the stretching direction and has a size of 33v in the stretching direction is pre-printed, then when forming the sheet joint portion 40, the size 33w of the design drawing printing portion 33 in the stretching direction stretches by 200% to become 100, and the size 33z of the design drawing printing portion 33 in the stretching direction in the natural length state returns to 20 to become 80. In addition, in a region with a large elastic limit elongation rate, if a deformed design drawing with a size of 80 that shrinks and deforms at a low deformation rate, such as 20%, and has a size of 33x in the stretching direction is pre-printed, then when forming the sheet joint portion 40, the size 33y of the design drawing printing portion 33 in the stretching direction stretches by 200% to become 160, and the size 33z of the design drawing printing portion 33 in the stretching direction in the natural length state returns to 80 to become 80. That is, the difference in the deformation of the design drawing printing portion 33 in the stretching direction between the two regions can be reduced.

[0146] Regarding the deformation rate of the deformed design drawing, it can be appropriately determined. For example, as shown in (b) of Figure 14 when the design drawing printing portion is provided in a stretching region and a non-stretching region, in order to make the appearance close to the standard magnification (100%) in the natural length state and reduce the deformation difference between the two regions, it is preferable to set the deformation rate of the deformed design drawing printed in the stretching region to approximately 20 - 40%, and set the deformation rate of the deformed design drawing printed in the non-stretching region to approximately 60 - 80%. In addition, in order to make the appearance close to the standard magnification (100%) in the elongated state during wearing and reduce the deformation difference between the two regions, it is preferable to set the deformation rate of the deformed design drawing printed in the stretching region to approximately 45 - 55%, and set the deformation rate of the deformed design drawing printed in the non-stretching region to approximately 60 - 80%.

[0147] In addition, in the case where a plurality of regions with different elastic limit elongation rates are provided, if there is a design drawing printing portion 33 that straddles the boundary between the regions, there is a concern that the design drawing printing portion does not deform identically on both sides of the boundary, resulting in deteriorated aesthetics. Therefore, in the case where a plurality of regions with different elastic limit elongation rates are provided, the following method is also a preferred method: the design drawing printing portion 33 is not provided at the boundary between the plurality of regions and at portions adjacent to both sides of the boundary. And preferably, the width of the portion adjacent to the boundary between the plurality of regions is approximately 3 to 10 mm as a whole on both sides of the boundary.

[0148] For example, in the case of welding the sheet joint portion 40 by ultrasonic sealing, the concave portions of the unevenness formed on the sheet layer on the side of the support roller 60 become deeper, and the concave portions of the sheet layer on the opposite side become shallower. The same applies during heat sealing. In this elastic film expansion and contraction structure 20X, for the design drawing printing portion 33 on the elastic film 30, the design drawing printing portion 33 is observed through the first sheet layer 20A or the second sheet layer 20B. Therefore, in the case of providing the design drawing printing portion 33 on the elastic film 30, if the design drawing printing portion 33 is provided on the surface of the side of the sheet layer (small unevenness layer) where the concave portion is shallower and the unevenness is smaller, there is an advantage that the aesthetics of the design drawing printing portion 33 becomes better. Such a structure can be manufactured by the following method: when forming the sheet joint portion 40, the elastic film 30 is supplied in such a manner that the design drawing printing portion 33 is provided on the surface 30P of the elastic film 30 on the side opposite to the side of the support roller 60. In particular, according to this manufacturing method, for the folds formed on the first sheet layer 20A and the second sheet layer 20B in the expansion and contraction region 80 in the natural length state, compared with the side of the support roller 60, the side of the sheet layer on the opposite side (20B in the illustrated manner) is formed more neatly and beautifully. Therefore, from this point of view, the aesthetics of the design drawing printing portion 33 also becomes better.

[0149] In this elastic film expansion and contraction structure 20X, since the design drawing printing portion 33 on the elastic film 30 is observed through the first sheet layer 20A or the second sheet layer 20B, the following structure is preferred: the light transmittance of the layer on the observation side among the first sheet layer 20A and the second sheet layer 20B is relatively high, for example, 60% or more, especially 80% or more. And the light transmittance is measured as follows using, for example, the flicker photometry color difference meter Z-300A manufactured by Nippon Denshoku Industries Co., Ltd. That is, first, measurement is performed in a state where a light-shielding object is disposed between one detection unit and the other detection unit, and zero-point correction is performed. Next, after removing the light-shielding object disposed between one detection unit and the other detection unit, measurement is performed in a state where there is no light-shielding object for shielding light, and standard correction is performed. Next, for the outer surface sheet as the object, measurement is performed in a state where it is disposed between one detection unit and the other detection unit.

[0150] Regarding the elastic film 30, it is not particularly limited as described above. However, since the design drawing printing portion 33 is to be provided, lateral contraction in the direction perpendicular to the stretching direction becomes a problem. That is, as Figure 23 shown, when the elastic film 30 changes from the state of the natural length shown by the double-dashed line to the state of being stretched in one direction shown by the solid line, corresponding to the amount of elongation, the width in the direction perpendicular to the elongation direction becomes narrower as it approaches the center in the stretching direction. This is called lateral contraction (or width reduction). When the minimum width (the width at the center in the length direction) of the elastic film 30 with a width of 33B is 33C when it is stretched 3.5 times in the length direction, the "lateral contraction ratio (width reduction rate)" indicating the degree of lateral contraction is (33B - 33C) / 33B × 100. When the elastic film 30 contracts from this lateral contraction state to the natural length, the width also returns to its original state. Regarding the stretching area 80, in most cases, the amount of elongation in the stretching direction varies corresponding to the position in the direction perpendicular to the stretching direction to fit the body surface composed of a complex curved surface. In such a case, the degree of lateral contraction also varies corresponding to the position in the direction perpendicular to the stretching direction. Therefore, when the design drawing printing portion 33 is provided on the elastic film 30 in the portion located in the stretching area 80, if the amount of elongation in the stretching direction varies corresponding to the position in the direction perpendicular to the stretching direction, the amount of deformation of the design drawing printing portion 33 caused by the lateral contraction of the elastic film 30 also varies corresponding to the position in the direction perpendicular to the stretching direction, and there is a concern about deterioration of aesthetics. Therefore, for the elastic film 30, it is desirable that the lateral contraction ratio is small, particularly preferably 25% or less, and more preferably 20% or less. If the elastic film 30 with such a low lateral contraction ratio is used, the manufacturing stability and on-line printability are also excellent.

[0151] <Explanation of Terms in the Specification>

[0152] Unless otherwise specifically stated in the specification, the following terms in the specification have the following meanings.

[0153] · "Front body part" and "rear body part" refer to the parts located on the front side and the rear side respectively with the center in the front-rear direction of the short-pants type disposable diaper as the boundary. In addition, the crotch part refers to the front-rear direction range including the center in the front-rear direction of the short-pants type disposable diaper, and in the case where the absorbent body has a narrowing part, it refers to the front-rear direction range of the part having the narrowing part.

[0154] · "Elastic limit elongation rate" refers to the elongation rate at the elastic limit in the stretching direction (in other words, in the state where the first layer and the second layer are fully unfolded), and is the amount of length when expressing the elastic limit as a percentage with the natural length set as 100%.

[0155] · "Area ratio" refers to the ratio of the object part in the unit area, which is calculated by dividing the total area of the object part (such as the sheet joint part 40, the opening of the through hole 31, the air vent) in the object area (such as the telescopic area 80, the non-telescopic area 70, the main telescopic part, the buffer telescopic part) by the area of the object area, and is expressed as a percentage. In particular, the "area ratio" in the area with a telescopic structure refers to the area ratio in the state of being stretched to the elastic limit in the telescopic direction. In the method of arranging a plurality of object parts at intervals, it is desirable to set the object area to a size containing 10 or more object parts and obtain the area ratio.

[0156] · "Elongation rate" refers to the value when the natural length is set to 100%.

[0157] · "Weight per unit area" is measured as follows. After pre-drying the sample or test piece, it is placed in a laboratory or device in a standard state (the temperature of the test site is 20 ± 5°C, and the relative humidity is 65% or less) until it reaches a constant weight state. Pre-drying means making the sample or test piece reach a constant weight in an environment with a relative humidity of 10 - 25% and a temperature not exceeding 50°C. In addition, for fibers with a conditioned moisture regain of 0.0%, pre-drying may not be required. From the test piece in a constant weight state, a sample with a size of 200 mm × 250 mm (±2 mm) is cut using a paper tightness plate (m tatami plate) (200 mm × 250 mm, ±2 mm). The weight of the sample is measured, and the weight per square meter is calculated 20 times as the weight per unit area.

[0158] · The "thickness" of the absorber is measured by using a thickness gauge (PEACOCK, dial thickness gauge, large type, model J - B (measurement range 0 - 35 mm) or model K - 4 (measurement range 0 - 50 mm)) manufactured by Ozaki Seisakusho Co., Ltd., with the specimen and the thickness measuring device being horizontal.

[0159] · The "thickness" other than the above is automatically measured by an automatic thickness measuring instrument (KES - G5 portable compression measuring instrument) under the conditions of a load of 10 N / cm 2 and a pressing area of 2 cm 2 .

[0160] · "Tensile strength" and "elongation at break (rupture elongation)" refer to the values measured by setting the test piece to a rectangular shape with a width of 35 mm and a length of 80 mm, and in accordance with JIS K7127:1999 "Plastics - Test methods for tensile properties -", setting the initial inspection interval (distance between graduations) to 50 mm and the tensile speed to 300 mm / min. As a tensile testing machine, for example, AUTOGRAPH AGS-G100N manufactured by SHIMADZU Corporation can be used.

[0161] · "Elongation stress" refers to the tensile stress (N / 35 mm) measured during elongation in the elastic region by a tensile test in accordance with JIS K7127:1999 "Plastics - Test methods for tensile properties -" with an initial inspection interval (distance between graduations) of 50 mm and a tensile speed of 300 mm / min. The degree of elongation can be appropriately determined according to the test object. Regarding the test piece, it is preferably set to a rectangular shape with a width of 35 mm and a length of 80 mm or more. However, in the case where a test piece with a width of 35 mm cannot be cut out, the test piece is made with the width that can be cut out, and the measured value is converted to the value in the case of a width of 35 mm. Additionally, even in the case where the object area is small and sufficient test pieces cannot be obtained, if comparing the magnitudes of elongation stress, at least a comparison can be made by appropriately using test pieces that are small but of the same size. As a tensile testing machine, for example, AUTOGRAPH AGS-G100N manufactured by SHIMADZU Corporation can be used.

[0162] · "Unfolded state" refers to a state where it is flat and unfolded without shrinkage and relaxation.

[0163] · The dimensions of each part, unless otherwise specified, refer to the dimensions in the unfolded state rather than the natural length state.

[0164] · In the case where there is no record of the environmental conditions during the test or measurement, the test or measurement is conducted in a laboratory or device under standard conditions (in the test site, the temperature is 20 ± 5°C, and the relative humidity is 65% or less).

[0165] Industrial Applicability

[0166] The present invention can be utilized not only in short-pant type disposable diapers as in the above examples, but also in various disposable diapers such as belt type and pad type, and all absorbent articles having a stretchable region such as sanitary napkins.

[0167] Reference Numeral Explanation

[0168] B: Rear body part; F: Front body part; T: Waist part; L: Middle part; 10: Inner package; 10B: Inner and outer fixing area; 11: Liquid-permeable topsheet; 12: Liquid-impermeable sheet; 13: Absorbent body; 13N: Narrowed part; 14: Wrapping sheet; 95: Pleated sheet; 96: Elastic member for pleated part; 17: Side part without absorbent body; 20: Outer package; 20A: First layer; 20B: Second layer; 20C: Folded-back part; 20X: Elastic film expansion and contraction structure; 21: Side seal part; 23: Waist end area; 24: Waist elastic member; 25: Shrinkage wrinkles; 29: Leg circumference line; 30: Elastic film; 31: Through hole; 40: Sheet joint part; 70: Non-stretch area; 80: Stretch area; 84: Weak stretch area; 90: Three-dimensional pleated part; 33: Design drawing printing part.

Claims

1. An absorbent article, characterized in that, the absorbent article has an elastic film expansion and contraction structure, in which an elastic film is laminated between a first sheet layer and a second sheet layer, and the first sheet layer and the second sheet layer are joined directly or with the elastic film interposed therebetween at a plurality of sheet joining portions arranged at intervals, the region having the elastic film expansion and contraction structure has an expandable region that can expand and contract and a non-expandable region that cannot expand and contract, the expandable region contracts in the expansion and contraction direction by the contraction force of the elastic film and can expand in the expansion and contraction direction, design pattern printing portions are provided at portions of the elastic film located in the expandable region and portions located in the non-expandable region, and a deformed design pattern is printed on the design pattern printing portions, the sheet joining portion is a portion where the first sheet layer and the second sheet layer are welded together through a through hole penetrating the elastic film, and is a portion where recesses are formed on non-opposing surfaces of both the first sheet layer and the second sheet layer due to the welding of the sheet joining portion, either the first sheet layer or the second sheet layer is a small uneven layer in which the recess is shallower than the recess of the other, the design pattern printing portion is provided on the surface of the elastic film on the side of the small uneven layer, the non-expandable region is set as a region where the elastic film is continuous in the width direction, but does not have a portion that is linearly continuous in the width direction due to the presence of the through hole, the deformation rate of the deformed design pattern printed in the expandable region is 45% - 55%, and the deformation rate of the deformed design pattern printed in the non-expandable region is 60% - 80%, so that the appearance of the absorbent article approaches the standard magnification in the extended state during wearing and the deformation difference between the expandable region and the non-expandable region is reduced.

2. The absorbent article according to claim 1, characterized in that, the elastic film expansion and contraction structure has a plurality of regions with different elastic limit elongation rates, and the design pattern printing portion is not provided at the boundaries of the plurality of regions of the elastic film and at portions adjacent to both sides of the boundaries, the width of the portion adjacent to the boundary of the plurality of regions is 3 mm - 10 mm as a whole on both sides of the boundary.

3. The absorbent article according to claim 1 or 2, characterized in that, the absorbent article is a short-pants type disposable diaper, and the short-pants type disposable diaper includes: an outer package body that constitutes a front body portion and a rear body portion; an inner package body containing an absorbent body, which is fixed to the outer package body; side seal portions, which are formed by joining the two side portions of the outer package body in the front body portion and the two side portions of the outer package body in the rear body portion together; an annular waist portion; and a waist opening and a pair of left and right leg openings, the outer package body in at least one of the front body portion and the rear body portion has the elastic film expansion and contraction structure in the entire width direction range corresponding to the portion between the side seal portions at least in a part of the front-rear direction, wherein the expansion and contraction direction of the expandable region of the elastic film expansion and contraction structure is the width direction.

4. A method for manufacturing an absorbent article, which is a method for manufacturing an absorbent article having an elastic film stretching structure. The elastic film stretching structure includes a stretching region that can stretch in one direction and a non-stretching region that cannot stretch. It is characterized in that, When forming the elastic film stretching structure, while the elastic film is stretched in the stretching direction of the stretching region and the elastic film is sandwiched between a first sheet layer and a second sheet layer, the elastic film, the first sheet layer, and the second sheet layer are ultrasonically sealed by passing between a support roller and an ultrasonic horn, and the first sheet layer and the second sheet layer are directly joined together at a plurality of spaced-apart locations to form sheet joining portions. And, using an elastic film pre-printed with design print portions at the portion that becomes the stretching region and the portion that becomes the non-stretching region as the elastic film, or, before the elastic film is stretched, design print portions are printed on the portion that becomes the stretching region and the portion that becomes the non-stretching region of the elastic film on the production line, and a deformed design is printed on the design print portions. The sheet joining portion is a portion where the first sheet layer and the second sheet layer are welded together through a through hole penetrating the elastic film. The non-stretching region is set as such a region: the elastic film is continuous in the width direction, but does not have a portion that is linearly continuous in the width direction due to the existence of the through hole. The deformation rate of the deformed design printed in the stretching region is 45% - 55%, and the deformation rate of the deformed design printed in the non-stretching region is 60% - 80%, so that the appearance of the absorbent article is close to the standard magnification in the stretched state during wearing and the deformation difference between the stretching region and the non-stretching region is reduced. The elastic film is supplied in such a manner that the design print portion is on the surface of the elastic film opposite to the support roller side. When welding the sheet joining portion, recesses are formed on the non-opposing surfaces of both the first sheet layer and the second sheet layer, and for the first sheet layer and the second sheet layer, the recess formed on the sheet layer on the support roller side is deeper than the recess formed on the sheet layer on the ultrasonic horn side.

5. The method for manufacturing an absorbent article according to claim 4, characterized in that, When forming the elastic film stretching structure, multiple stretching regions with different elastic limit elongation rates are formed by making the patterns of the sheet joining portions different. When printing the design print portions, printing a deformed design as follows: for a region with a smaller elastic limit elongation rate, the deformed design shrinks and deforms in the stretching direction at a higher deformation rate.

6. The method for manufacturing an absorbent article according to claim 4, characterized in that, When forming the elastic film stretching structure, multiple regions with different elastic limit elongation rates of the product are formed. Design print portions are not printed at the boundaries of the multiple regions on the elastic film and at the portions adjacent to both sides of the boundaries. The width of the portion adjacent to the boundary of the multiple regions is 3 mm - 10 mm in total on both sides of the boundary.

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