JP5250372B2 - Pants-type disposable diaper - Google Patents

Description

  The present invention relates to a pants-type disposable diaper.

  Elastic members made of thread rubber, flat rubber, or the like are arranged in an extended state at the waist opening or leg opening of the pant-type disposable diaper, thereby forming a stretchable waist gather or leg gather. In a diaper having such a configuration, the diaper is fixed to the wearer's body by a portion where the elastic member exists. Therefore, the contraction force acts intensively on the site where the elastic member exists, and the trace of the elastic member, that is, the so-called rubber mark is easily attached to the wearer's body. Moreover, many wrinkles generate | occur | produce in a waist gather and a leg gather by the contraction force of an elastic member. As a result, the fit of diapers is limited.

  In a disposable diaper provided with an absorbent main body including an absorbent core and an exterior body joined to the non-skin contact surface side of the absorbent main body separately from the pants-type diaper having such a configuration, a diaper for a wearer For the purpose of improving the fit, there is also known one using a stretchable sheet for the exterior body (see, for example, Patent Documents 1 and 2). According to such a disposable diaper, since it is not necessary to use a linear elastic member such as rubber thread in order to exhibit stretchability in the exterior body, it is excellent in appearance and softness of the diaper before or during wearing. In addition, problems such as rubber marks at the time of wearing by a linear elastic body can be solved.

Japanese Patent No. 2731204 Japanese Patent No. 3340032

  The pants-type disposable diaper described in the cited document 1 employs an elastomeric non-woven outer cover in which an elastic non-woven web is fitted to one or more non-gatherable non-woven webs as an exterior body. Since the outer cover has a substantially single layer structure, if the outer cover is thin, the outer cover is insufficient in strength and easily broken. The lack of strength of the outer cover can be resolved by increasing the basis weight. However, since such a stretchable sheet is generally expensive to manufacture, an increase in the basis weight of the outer cover leads to an increase in the manufacturing cost of the entire diaper. It is hard to say that it is effective in eliminating the shortage.

  The pants-type disposable diaper described in the cited document 2 has a skin contact surface side (inside the exterior body) as an exterior body, and a stretchable sheet that can be stretched in the left-right width direction of the diaper, and non-skin A back sheet comprising a non-stretchable non-woven fabric that constitutes the contact surface side (outside of the exterior body) and overlaps the stretchable sheet is employed. In the stretchable sheet and the non-stretchable non-woven fabric, at least one synthetic resin component is melted and solidified and integrated with each other at the intermittently disposed fixing sites. Thus, since the exterior body in the pants-type disposable diaper described in the cited document 2 includes the stretchable sheet on the inside and the non-stretchable sheet on the outside and is partially joined between the sheets, the stretchability is When the sheet is contracted, a large number of pleats that protrude toward the outer side of the diaper are formed on the outer surface of the diaper (the surface of the non-stretchable sheet) other than the fixing part. For this reason, the pants-type disposable diaper described in the cited document 2 has a problem that it does not look good and the outer body is easily damaged by hooking the pleats on the outer surface to surrounding objects.

  Accordingly, an object of the present invention is to provide an exterior body that is not easily torn and is flexible and has sufficient breathability and stretchability, and can provide good fit on the abdominal side and back side, and also has good appearance. Is to provide a simple pants-type disposable diaper.

  The present invention includes an absorbent body including an absorbent core, and an exterior body that is positioned on the non-skin contact surface side of the absorbent body and fixes the absorbent body, and the exterior body on the back side portion A pants-type disposable diaper in which a pair of side seals, a waist opening, and a pair of leg openings are formed by joining both side edges of the outer body and both side edges of the exterior body at the ventral side, The exterior body in each of the head part and the back side part has a structure in which an outer layer sheet made of a stretchable sheet and an inner layer sheet made of a non-stretchable sheet are laminated, and the exterior body in the crotch part has a non-stretchable sheet. Between the outer layer sheet and the inner layer sheet in each of the ventral side portion and the back side portion, and are joined together by an adhesive, and the abdominal side portion and the dorsal side portion, respectively. Area that overlaps the absorbent body , The outer layer sheet and at least one of the inner layer sheet is obtained by achieving the above object by providing a shorts type disposable diaper fused junction both are integrated by melting and solidifying is formed.

  The pants-type disposable diaper of the present invention has an exterior body that is not easily torn and is flexible and has sufficient breathability and stretchability. good.

  Hereinafter, a pants-type disposable diaper of the present invention will be described based on preferred embodiments with reference to the drawings. 1 to 6 show a pants-type disposable diaper 1 according to a first embodiment of the present invention.

  2 and 3, the diaper 1 is disposed between a liquid-permeable top sheet 2, a liquid-impervious or liquid-impervious (water repellent) back sheet 3, and both sheets 2 and 3. A substantially vertically long absorbent main body 10 having a liquid-retainable absorbent core 4 and the absorbent main body 10 positioned on the back sheet 3 side (non-skin contact surface side) of the absorbent main body 10. The exterior body 11 which fixes The absorbent main body 10 and the exterior body 11 are joined by an adhesive.

  As shown in FIG. 2, the diaper 1 has an abdominal side A disposed on the abdomen side of the wearer when worn, a back side B disposed on the back side, and a crotch C positioned therebetween. Yes. The exterior body 11 forms the outer surface of the diaper 1, and in the unfolded state (see FIG. 2), both side edges thereof have an hourglass shape that is inwardly bound in the central portion in the longitudinal direction. In the exterior body 11, both side edges A1, A2 on the ventral side A and both side edges B1, B2 on the back side B are joined to each other, and the diaper 1 is joined to the pair of side seal parts S by the joining. , S, a waist opening 5 and a pair of leg openings 6 and 6 are formed.

  In the present specification, the skin contact surface is a surface directed toward the wearer's skin when wearing a diaper, and the non-skin contact surface is the underwear side (the side opposite to the wearer's skin) when wearing the diaper. ). The longitudinal direction is a direction along the longitudinal direction of the diaper or its constituent members, and the width direction is a direction orthogonal to the longitudinal direction.

  The absorbent main body 10 is formed by integrating the top sheet 2, the back sheet 3, and the absorbent core 4. As the top sheet 2, the back sheet 3, and the absorbent core 4, various types conventionally used for this type of article can be used without particular limitation. For example, various nonwoven fabrics or apertured films can be used as the top sheet, and a resin film, a laminate of a resin film and a nonwoven fabric, or the like can be used as the back sheet. The absorbent core 4 may be composed of a superabsorbent polymer particle and a fiber material and covered with tissue paper (not shown).

  As shown in FIGS. 2 and 3, side cuffs 8, 8 made of a liquid-resistant or water-repellent and breathable material are formed on the left and right sides of the absorbent body 10 in the longitudinal direction. Yes. In the vicinity of the free end of each side cuff 8, a plurality of side cuff elastic members 81a are arranged in an expanded state. The side cuff 8 stands up when the diaper is worn to prevent the liquid from flowing out. In the sheet material 82 for forming the side cuffs 8 and 8, the end opposite to the free end is fixed between the absorbent core 4 and the back sheet 3. It may be fixed between the body 11.

  As shown in FIGS. 4 and 5, the exterior body 11 in each of the ventral portion A and the back portion B includes outer layer sheets 12A and 12B made of a stretchable sheet and inner layer sheets 13A and 13B made of a non-stretchable sheet. It has a laminated structure. On the other hand, the exterior body 11 in the crotch part C has a structure in which two non-stretchable sheets 13C and 12C are laminated as shown in FIGS.

  In the first embodiment, the inner layer sheets 13A and 13B in the ventral part A and the dorsal part B extend from the ventral part A through the crotch part C to the dorsal part B as shown in FIGS. It consists of a sheet of non-stretchable continuous sheets 13, and the outer layer sheets 12A and 12B in the ventral side portion A and the backside portion B are composed of separate stretchable sheets.

  The continuous sheet 13 is non-stretchable as a whole, including the portion located at the crotch C. The portion located at the crotch C of the continuous sheet 13 is non-stretchable that forms the exterior body 11 at the crotch C. This is a conductive sheet 13C. In the diaper 1 of the first embodiment, in addition to the first non-stretchable sheet 13 </ b> C made of the continuous sheet 13 in the crotch C, the second non-skin layer laminated on the non-skin contact surface side of the continuous sheet 13. It has an elastic sheet 12C. As shown in FIG. 6, the second non-stretchable sheet 12C has front and rear end portions 12Ce and 12Ce in the diaper longitudinal direction (vertical direction in FIG. 2), and the end portions 12Ae and 12Be of the outer layer sheets 12A and 12B, respectively. And the ends are joined together by a known heat seal method. The joint portion 14 extends in a strip shape over substantially the entire width of the diaper 1 in the width direction.

  The stretchable sheet forming the outer layer sheets 12A and 12B only needs to have stretchability in at least the diaper width direction (left-right direction in FIG. 2) when the diaper is in an unfolded state. The non-stretchable continuous sheet 13 forming the inner layer sheets 13A and 13B does not have stretchability in at least the diaper width direction when the diaper is in a developed state. It is preferable that the second non-stretchable sheet 12C does not have stretchability in at least the diaper width direction and does not have stretchability in the diaper longitudinal direction and width direction when the diaper is in an unfolded state. .

  As in the first embodiment, the outer layer sheets 12A and 12B in the abdominal part A and the dorsal part B and the non-stretchable sheet 12C arranged in the crotch part C are joined to form one composite outer layer sheet 12. When formed, the part where the non-stretchable sheet 12C is arranged in the longitudinal direction of the diaper is referred to as a crotch part C. In this case, the length Lc (see FIG. 6A) of the non-stretchable sheet 12C in the longitudinal direction of the diaper is preferably at least 30% or more of the total length L of the diaper, and is 40-60% long. It is more preferable that The composite outer layer sheet 12 has portions 12E and 12E that are folded back toward the absorbent main body 10 at the peripheral edge of the waist opening.

  In the diaper 1 of 1st Embodiment, as shown in FIG.5 and FIG.6, between the outer-layer sheet | seat 12A, 12B and inner-layer sheet | seat 13A, 13B in each of the ventral | abdominal part A and the back | dorsal part B, the adhesive 15 ( 6 (a), and is joined to the entire region (hereinafter also referred to as an absorbent main body arrangement region) L10 that overlaps with the absorbent main body 10 in each of the ventral side A and the back side B. In addition, at least one of the outer layer sheets 12A and 12B and the inner layer sheets 13A and 13B is melted and solidified to form a large number of melt-bonded portions 17 in which both are integrated. That is, the adhesive 15 and the melt bonded portion 17 are present in the absorbent main body arrangement region L10. The outer layer sheets 12A and 12B are joined to the inner layer sheets 13A and 13B in an expanded state. 6A shows a single continuous sheet 13 constituting the inner layer sheets 13A and 13B in the abdominal part A and the back part B and the first non-stretchable sheet 13C in the crotch C. In FIG. 6 (b), the outer layer sheets 12A and 12B in the abdominal side A and the back side B and the second non-stretchable sheet 12C in the crotch C are joined and integrated. A composite outer layer sheet 12 is shown. Also, the adhesive 15 that is disposed between the continuous sheet 13 and the composite outer layer sheet 12 and adheres between the two sheets, and the absorbent main body arrangement region L10 are formed so that both the sheets 13 and 12 are integrated. A melt joint 17 is shown on the continuous sheet 13.

  In this way, in each of the ventral portion A and the back portion B, 1) the continuous sheet 13 (inner layer sheet) constituting the exterior body 11 and the composite outer layer sheet 12 are entirely joined with the adhesive 15. 2) Since both sheets 13 and 12 are integrated via the melt-bonded portion 17 in the absorbent main body arrangement region L10, the inherent flexibility and breathability of both sheets 13 and 12 are provided. It is possible to improve the bonding strength between the sheets 13 and 12 without impairing the various characteristics such as the above. Therefore, the diaper 1 has the exterior body 11 which is not easily torn, and the stretchability of the back side part A and the abdomen side part B is good, and the back side part A and the abdomen side part B are good for the wearer when worn. To fit. Moreover, parts other than the absorptive main body arrangement | positioning area | region L10 in the outer surface of the diaper 1 and the inner surface of the exterior body 11 are soft, and the touch is good. Moreover, when both the sheets 13 and 12 have air permeability, since the air permeability is maintained favorable, the diaper 1 becomes difficult to become stuffy. In particular, the adoption of the above 1) suppresses the floating of the outer layer sheets 12A and 12B made of stretchable sheets, so that the diaper 1 is excellent in appearance (appearance).

  In the first embodiment, in order to optimize the texture of the exterior body 11, the melt-bonded portion 17 is provided only in the absorbent main body arrangement region L 10 on the inner surface of the exterior body 11. If it is the range which does not spoil, it is sufficient to provide the melt | fusion joining part 17 besides the absorptive main body arrangement | positioning area | region L10. Examples of the formation region of the melt bonding portion 17 other than the absorbent main body arrangement region L10 include a peripheral vicinity region of the absorbent main body arrangement region L10.

  On the other hand, if the above 2) is not adopted and the joining between the sheets 13 and 12 is based only on the entire joining with the adhesive, the joining between the sheets 13 and 12 is practically sufficient. If an amount of adhesive that can impart strength is used, the adhesive-applied portions of both sheets 13 and 12 become hard and the flexibility is impaired, and the stretchability and breathability may be impaired. Moreover, if the application amount of the adhesive applied between the sheets 13 and 12 is reduced due to fear of a decrease in flexibility or the like, the bonding strength between the sheets 13 and 12 may be insufficient, and the exterior body 11 may be easily broken. is there.

  Here, between the outer layer sheets 12A and 12B and the inner layer sheets 13A and 13B in the ventral side portion A and the back side portion B, respectively, is bonded to the entire surface by the adhesive 15 so that both sheets overlap. It means that the two sheets 12A and 13A and the two sheets 12B and 13B are joined to each other over almost the entire area of the portion, and the entire joining surface of each sheet (ie, the area of the surface of the joining surface side of each sheet is 100). %) Need not be bonded. Both sheets 12A and 13A (12B and 13B) are preferably joined at least 80% or more of the area of the part where both sheets overlap, and more preferably 90% or more. preferable.

As the adhesive 15, various known adhesives can be used, but a hot-melt adhesive is preferable. The application amount of the adhesive 15 has a practically sufficient bonding strength from the viewpoint of not damaging the inherent properties of the continuous sheet 13 and the composite outer layer sheet 12 as much as possible, such as flexibility, breathability and stretchability. It is desirable to reduce as much as possible. Specifically, the coating amount of the adhesive 15 is preferably 0.2 to 5 g / m ² , more preferably 0.4 to 3 g / m ² in terms of solid content.

  Note that one or more (a plurality in the first embodiment) waist elastic members 51, 51 are provided on the peripheral edge 50 of the waist opening 5 along the opening peripheral edges 5 a, 5 b of the waist opening 5. Further, one or a plurality of leg part elastic members (a plurality in the first embodiment) are provided along the peripheral edge 6 c of the leg opening 6 at the peripheral parts 60, 60 of the leg opening 6. 61a and 61b are arranged. These elastic members 51, 61a, 61b are sandwiched and fixed between the outer layer sheets 12A, 12B and the inner layer sheets 13A, 13B in an expanded state via the adhesive 15. Thereby, the fitting property of the peripheral edge part 50 of the waist opening part 5 and the peripheral edge parts 60 and 60 of the leg opening part 6 can be improved without being restricted by the expansion and contraction characteristics of the outer layer sheets 12A and 12B. As the waist elastic member 51 and the leg elastic members 61a and 61b, elastic materials such as natural rubber, polyurethane resin, foamed urethane resin, and hot melt elastic member are made into a thread (thread rubber) or a belt (flat), respectively. Those formed into (rubber) are preferably used. In this way, when the thread-like or belt-like elastic members 51, 61a, 61b are fixed in a state of being sandwiched between the outer layer sheets 12A, 12B and the inner layer sheets 13A, 13B, such elastic members are Compared to the case of fixing to an exterior body made of a sheet, the elastic member can prevent the wearer from feeling uncomfortable and can also prevent the appearance of the diaper from being deteriorated.

  The melt-bonded portion 17 has a substantially rectangular shape in plan view, and is formed in a large number in the absorbent main body arrangement region L10. A large number of the melt-bonded portions 17 are arranged in rows at predetermined intervals in the diaper longitudinal direction with the longitudinal direction thereof aligned with the diaper longitudinal direction, and the rows of the melt-joined portions 17 are predetermined in the diaper width direction. They are arranged at intervals. The melt-bonded portion 17 can be formed by utilizing a known hot embossing process. When heat embossing is used, heat embossing may be performed from the sheet 13 (inner layer sheet) side, or heat embossing may be performed from the sheet 12 (outer layer sheet) side.

  It is preferable that the melt | fusion joining part 17 is distributed substantially uniformly over the substantially whole region of the absorptive main body arrangement | positioning area | region L10. Further, the total area of the melt bonded portion 17 (the total area of the plurality of melt bonded portions 17) occupies 3% or more, particularly 5 to 15% of the total area of the absorbent main body arrangement region L10. It is preferable at the point which can fully provide the joint strength of an inner layer sheet.

  As described above, the joint portion 14 between the outer layer sheets 12A and 12B in the abdominal part A and the back part B and the second non-stretchable sheet 12C in the crotch part C is formed by a known heat seal method. Thus, the embossing pattern by hot embossing in the melt-bonded portion 17, that is, the absorbent main body arrangement region L <b> 10 becomes inconspicuous, leading to an improvement in the appearance of the diaper 1. From the viewpoint of making the effect of the joint part (heat seal part) 14 by such a heat seal method more effective, the joint part 14 may span the entire width of the absorbent main body arrangement region L10 as shown in FIG. The width W (the length along the longitudinal direction of the joint 14) is preferably 5 to 50 mm, particularly preferably 10 to 30 mm.

  As shown in FIG. 2, the dimensions and ratios of the respective parts described in this specification are in a natural state (external force such as tension is applied) with the diaper in an unfolded state and the contraction force by the elastic members of the waist opening and the leg opening is released. The value measured in the state of not acting) or based on it. In addition, each measured value is measured based on the dimension of the composite outer layer sheet 12 in a natural state.

  The bonding strength between the outer layer sheets 12A, 12B and the inner layer sheets 13A, 13B in the ventral side part A and the back side part B, respectively, is the side seal part (the part that is joined to form the side seal part) S, S and waist The peripheral portion 50 of the opening 5 is larger than the portion surrounded by the outer edge of the diaper including the side seal portions S and S and the peripheral portion 50 of the waist opening 5. That is, the portion surrounded by the outer rim of the diaper in each of the ventral side A and the back side B (hereinafter, also referred to as an inner part) includes side seal portions S, S and a waist opening constituting the diaper outer rim. 5, the bonding strength between the outer layer sheets 12A and 12B and the inner layer sheets 13A and 13B is small. The diaper outer edge portion is an edge portion that forms the outline of the diaper 1 in each of the ventral side portion A and the back side portion B. Specifically, the side seal portions S and S and the peripheral edge portion of the waist opening 5 50 and a pair of leg openings 6 and 6, each of which is a continuous portion formed of a part of the peripheral edge 60.

  By adopting such a specific distribution of joint strength, each of the side portions S, S and the peripheral portion 50 of the waist opening 5 where strength is particularly required is provided with practically sufficient strength, and each of the inner portions is configured. Characteristics such as flexibility inherent to the sheet can be maintained, and the exterior body 11 having flexibility and strength can be obtained. In addition, the peripheral part 50 of the waist opening part 5 here means the part within 40 mm from the opening peripheral edge 5a, 5b (refer Fig.6 (a)) of the waist opening part 5. FIG. Moreover, the width | variety (length along the diaper width direction of the side seal part S) of the side seal part S is about 10 mm normally.

  The bonding strength is measured as follows. First, from a pants-type disposable diaper as shown in FIG. 1, a measurement sample is prepared for each predetermined part as follows. In the following, the ventral part A will be described as an example, but a measurement sample is prepared for the back part B in the same manner. About the measurement sample of the said inner part, outer layer sheet | seat 12A, 12B and inner layer sheet | seat 13A, 13B in the area | region which separated 50 mm or more inward of the diaper 1 from the outer edge which forms the outline of the diaper 1 in the ventral part A From the laminate, the diaper is naturally cut into three rectangular shapes of 2 cm in the longitudinal direction of the diaper and 7 cm in the width direction so as to include the absorbent main body arrangement region L10, and these are used as measurement samples. About the measurement sample of the side seal part S, the side seal part S is included from the state where the side seal part S of the abdominal part A and the side seal part S of the dorsal part B are joined as shown in FIG. As described above, in a natural state of the diaper, three rectangular shapes of 2 cm in the longitudinal direction of the diaper and 5 cm in the width direction are cut out to obtain a measurement sample. About the measurement sample of the peripheral part 50 of the waist opening part 5, it is the part within 40 mm from the opening peripheral edge of this opening part 5, and the outer layer sheet | seat 12A, 12B and inner layer sheet | seat 13A, 13B in the arrangement | positioning area | region of the waist part elastic member 51. From the laminated body, three rectangular shapes of 2 cm in the longitudinal direction of the diaper and 5 cm in the width direction are cut out in a natural state of the diaper, and this cut out portion is used as a measurement sample. In addition, the arrangement | positioning area | region of a waist part elastic member is the said waist part elastic member in the ventral part or back side part, when only one waist part elastic member exists in each of a ventral part and a back side part. It means a region that overlaps with the elastic part of the waist, and when there are multiple waist elastic members on the abdomen and the dorsal part, at the opening peripheral edge of the waist opening in the abdomen or dorsal part It means a region sandwiched between the nearest waist elastic member and the waist elastic member furthest away from the peripheral edge of the opening.

  In addition, regarding the measurement sample of the peripheral portion 50 of the waist opening 5, the waist elastic member 51 is disposed between the outer layer sheet 12A (12B) and the inner layer sheet 13A (13B) in the peripheral portion 50 as shown in FIG. In the case where the peripheral edge portion 50 has a form as shown in FIG. 7, that is, when the waist elastic member 51 is not covered with the inner layer sheet 13A (13B), the peripheral edge portion of the waist opening 5 The measurement sample of 50 is a portion within 40 mm from the opening peripheral edge 5a, 5b (see FIG. 6 (a)) of the waist opening 5 toward the crotch direction in the diaper longitudinal direction and the arrangement of the waist elastic member 51 In a region sandwiched between outer layer sheets, three rectangular shapes of 2 cm in the longitudinal direction of the diaper and 5 cm in the width direction are cut out in the natural state of the diaper. The part as a measurement sample. The bonding strength of each measurement sample thus prepared is measured by the following measurement method using a tensile tester ("Tensilon" RTA-100 from Orientec Co., Ltd.).

[Measurement method of bonding strength of the inner part]
Using the measurement sample cut out as described above, the outer layer sheet and the inner layer sheet are peeled off by about 2 cm in the diaper width direction, and the gripping margin is fixed at 3 cm between the chucks, and then peeled off at a speed of 300 mm / min. Three sheets are measured, and the average value of the maximum average value load is defined as the joint strength of the inner part. The bonding strength of the dorsal side B is also measured in the same manner as the ventral side A.

[Measurement method of bonding strength of side seal part S]
Using the measurement sample cut out as described above, the outer layer sheet and the inner layer sheet are peeled off from the inner side of the ventral side A to the inner end of the side seal portion S in the diaper width direction, and held between 3 cm between the chucks. Is peeled off at a speed of 300 mm / min. Three sheets are measured, and the average value of the maximum point loads is defined as the bonding strength of the side seal portion S. The bonding strength of the dorsal side B is also measured in the same manner as the ventral side A.

[Measuring method of bonding strength of peripheral edge of waist opening]
Using the measurement sample cut out as described above, the outer layer sheet and the inner layer sheet are peeled off by about 2 cm in the diaper width direction, and the gripping margin is fixed at 3 cm between the chucks, and then peeled off at a speed of 300 mm / min. Three sheets are measured, and the average value of the maximum average load is defined as the bonding strength of the peripheral edge of the waist opening. The bonding strength of the dorsal side B is also measured in the same manner as the ventral side A.

The bonding strength Z between the outer layer sheets 12A, 12B and the inner layer sheets 13A, 13B in the inner part of each of the ventral part A and the dorsal part B is preferably 0.01 N / 20 mm to 0.5 N / 20 mm, More preferably, it is 0.03N / 20mm-0.1N / 20mm. Further, the ratio (Z / Z1) of the bonding strength Z and the bonding strength Z1 between the outer layer sheets 12A, 12B and the inner layer sheets 13A, 13B in the side seal portions S of the ventral side A and the back side B, The ratio of the bonding strength Z to the bonding strength Z2 between the outer layer sheets 12A, 12B and the inner layer sheets 13A, 13B at the peripheral edge 50 of the waist opening 5 of each of the ventral side A and the back side B (Z / Z2) is preferably 3 × 10 ^{−4 to} 0.5, more preferably 1.5 × 10 ^{−3 to} 0.05.

  The specific distribution of the bonding strength between the outer layer sheets 12A and 12B and the inner layer sheets 13A and 13B in the ventral portion A and the back portion B described above is realized by appropriately adjusting the application amount of the adhesive 15 and the like. can do. In general, the greater the amount of adhesive applied, the greater the bonding strength between the sheets. Specifically, for example, a) a method in which the application amount of the adhesive 15 in the side seal portions S, S and the peripheral portion 50 of the waist opening 5 is made larger than the application amount of the adhesive in the inner portion; Examples include a method in which substantially the entire regions of the side seal portions S and S and the peripheral edge portion 50 of the waist opening 5 are joined together with the adhesive 15 by a heat seal method, a high frequency seal method, an ultrasonic seal method, or the like. In the method (a), the application amount of the adhesive 15 on the side seal portions S and S and the peripheral edge 50 of the waist opening 5 is preferably set within the above-described range.

  The joining mode between the outer layer sheets 12A, 12B and the inner layer sheets 13A, 13B in the ventral side part A and the back side part B is as described above, whereas the two non-stretchable sheets 13C in the crotch part C are as described above. , 12C, as shown in FIG. 6, the entire surface except for the rectangular portion 16 provided at the center of the crotch C is joined with the adhesive 15 in the same manner as the ventral portion A and the back portion B. However, the melted joint portion 17 is not formed.

  In addition, the rectangular part 16 is the width direction center of the diaper 1 which the leg part elastic member continuously introduced between the strip | belt-shaped original fabric of the continuous sheet 13 and the strip | belt-shaped original fabric of the composite outer layer sheet | seat 12 at the time of manufacture of the diaper 1 When cutting at a portion corresponding to the portion, the vicinity of the cut end portion can be contracted to the left and right, and the leg portion elastic members 61a and 61b do not exist at the center portion in the width direction of the crotch C due to the contraction. A region is formed, and the width shrinkage of the absorbent main body 10 is further prevented.

  The joining strength between the two non-stretchable sheets 13C and 12C in the crotch part C is greater at the peripheral edge portions 60 and 60 of the leg opening 6 than at the portion sandwiched between the peripheral edge portions 60 and 60. Yes. In other words, the joint strength between the sheets 13C and 12C is smaller in the portion sandwiched between the peripheral portions 60 and 60 in the crotch portion C (hereinafter also referred to as the crotch inner portion) than in the peripheral portions 60 and 60. ing.

  The stretchable sheet used for the outer layer sheets 12A and 12B of the diaper 1 will be described. The outer layer sheets 12A and 12B have elasticity as described above. “Elasticity” means that the maximum elongation in at least one direction is 100% or more, and the elongation is 100% or more in one direction, the elongation is 100% or more and then stretched when contracted. It means that the recovery rate (elongation recovery rate at 100% elongation) is at least 70% or more. In the case of an elastic sheet having a plurality of directions having a maximum elongation of 100% or more, the elongation recovery rate may be 70% or more in only one of the directions.

  The outer layer sheets 12A and 12B can extend larger in the diaper width direction than in the diaper longitudinal direction (vertical direction in FIG. 2). More specifically, in the diaper width direction, it stretches greatly and contracts after stretching (maximum elongation of 100% or more and elongation recovery rate of 70% or more), but in the diaper longitudinal direction, it stretches only slightly (for example, , Maximum elongation of 50% or less).

The elongation recovery rate of the elastic sheet is measured by the following measuring method.
[Method for measuring elongation recovery rate]
A sample piece of an elastic sheet having a length of 50 mm and a width of 25 mm is prepared, and the sample piece is fixed at a chuck interval K0 using a tensile tester ("Tensilon" RTC-1150A from Orientec Co., Ltd.), 300 mm / min After stretching to 100% stretched length K2 (K2 = K0 × 2) at the same speed, after starting to return at the same speed as the tensile speed, the length of the sample piece was restored after stretching. The length is K1. The elongation recovery rate at 100% elongation is calculated from the following equation.
Elongation recovery rate at 100% elongation (%) = [(K2−K1) / (K2−K0)] × 100

  As the stretchable sheet for forming the outer layer sheets 12A and 12B, various sheets having stretchability can be used. For example, the outer layer sheets 12A and 12B are preferably formed from a nonwoven fabric made of thermoplastic fibers from the viewpoint of improving air permeability. The outer layer sheets 12A and 12B are preferably made of a laminated sheet from the viewpoint of improving the texture, and at least the layer on the non-skin contact surface side is formed of an air-through nonwoven fabric. An elastic sheet made of elastic fiber (elastomer) having elasticity is generally not preferable from the viewpoint of texture because it gives a slimy feeling when touched.

  More specifically, examples of the elastic sheet forming the outer layer sheets 12A and 12B include (1) a sheet in which a fiber layer that can be extended on both sides or one side of an elastic fiber layer is integrated, and (2) a net. A sheet in which stretchable fiber layers are integrated on both sides or one side of the elastic sheet, (3) a sheet in which stretchable fiber layers are integrated on both sides or one side of the elastic film, 4) It is preferable to use a stretchable sheet or the like in which a large number of elastic filaments arranged so as to extend in one direction without crossing each other are bonded to a stretchable nonwoven fabric over their entire length in a substantially non-stretched state. Can do. Examples of the method of integrating the elastic fiber layer and the extensible fiber layer include, for example, laminating them and hydroentangled them, or entangled fibers by air-through, etc., heat embossing, adhesive, ultrasonic bonding, etc. The method of letting it be mentioned.

  As the sheet of (1), for example, (a) a substantially inelastic non-elastic fiber layer is disposed on at least one surface of the elastic fiber layer, and both fiber layers have a fiber form of the constituent fibers of the elastic fiber layer. In a state where the fibers are kept in contact with each other by thermal fusion at the intersection of the fibers, a part of the constituent fibers of the inelastic fiber layer has entered the elastic fiber layer and / or a part of the constituent fibers of the elastic fiber layer Examples include stretchable nonwoven fabrics that are in a state of entering into the inelastic fiber layer. Moreover, as said (1)-(3) sheet | seat, it has (b) the elastic layer which has elastic elasticity, and a substantially inelastic nonelastic fiber layer, and both the said layers are laminated | stacked on the thickness direction. A stretchable sheet obtained by stretching a partially bonded laminated sheet can be preferably used.

  The stretchable nonwoven fabric (a) will be described. At the interface between the elastic fiber layer and the non-elastic fiber layer and in the vicinity thereof, the intersection of the constituent fiber of the elastic fiber layer and the constituent fiber of the non-elastic fiber layer is heat-sealed, and it is bonded substantially uniformly over the entire surface. Has been. By joining all over, it is prevented that both layers are separated and a space is formed, and a stretchable nonwoven fabric having a multi-layer structure with a sense of unity, such as a single nonwoven fabric. "The state in which the constituent fibers of the elastic fiber layer maintain the fiber form" means that even if most of the constituent fibers of the elastic fiber layer are given heat, pressure, etc., the film or film-fiber structure A state that is not deformed. In the elastic fiber layer, the intersections of the constituent fibers are thermally fused in the layer. Similarly, in the non-elastic fiber layer, the intersection of the constituent fibers is thermally fused in the layer.

  When non-elastic fiber layers are arranged on both sides of the elastic fiber layer, at least one of the constituent fibers is in a state where a part of the constituent fibers enter the elastic fiber layer and / or one of the constituent fibers of the elastic fiber layer. The part is in a state of entering at least one of the inelastic fiber layers. In order to allow the constituent fibers of the non-elastic fiber layer to enter the elastic fiber layer and / or to allow the constituent fibers of the elastic fiber layer to enter the non-elastic fiber layer, the constituent fibers of the elastic fiber layer and the constituent fibers of the non-elastic fiber layer are changed. It is preferable that at least one of the non-elastic fiber and the elastic fiber is in a web state (a state where heat fusion is not performed) before the heat fusion treatment. From the viewpoint of allowing the constituent fibers to enter other layers, the fiber layer in the web state is preferable because the short fibers have a higher degree of freedom than the long fibers.

  Moreover, it is preferable to use the air-through method in order to allow the constituent fibers of the non-elastic fiber layer to enter the elastic fiber layer and / or to allow the constituent fibers of the elastic fiber layer to enter the non-elastic fiber layer. By using the air-through method, the constituent fibers can be made to enter the opposing fiber layer, and the constituent fibers can be easily made to enter from the opposing fiber layer. Further, by using the air-through method, it becomes easy to allow the constituent fibers of the inelastic fiber layer to enter the elastic fiber layer while maintaining the bulkiness of the inelastic fiber layer. In particular, when the constituent fibers of the inelastic fiber layer are entangled with the constituent fibers of the elastic fiber layer, it is preferable that they are entangled only by the air-through method. In order to entangle the fibers by the air-through method, the gas blowing pressure, the blowing speed, the basis weight and thickness of the fiber layer, the conveyance speed of the fiber layer, etc. may be adjusted appropriately. Preferably it is done.

  In the hot air treatment (particularly, the air-through method), a part of the constituent fibers of the non-elastic fiber web enters the elastic fiber web, and at the same time, the constituent fibers of the non-elastic fiber web and / or the constituent fibers of the non-elastic fiber web are elastic. The constituent fibers of the fiber web are heat-sealed at their intersections. In this case, care should be taken so that the constituent fibers of the elastic fiber web do not become a film or film-fiber structure by the hot air treatment.

  The elastic fiber layer has a property that it can be stretched and contracts when tension is released. The elastic fiber layer preferably has a residual strain of 20% or less, particularly 10% or less when contracted after 100% elongation in at least one direction parallel to the surface. This residual strain value is preferably satisfied at least in the diaper width direction, and more preferably in both the diaper width direction and the diaper longitudinal direction.

  The elastic fiber layer is an aggregate of fibers having elasticity. Examples of a method for forming an elastic fiber include a melt blown method in which a molten resin is extruded from a nozzle hole, and the extruded molten resin is elongated with hot air to thin the fiber, and a semi-molten resin is cooled with cold air. There is also a spunbond method in which stretching is performed by a mechanical draw ratio. As a special method of the melt blown method, there is a spinning blow method in which the spun bond method is combined with the melt blown method.

  The elastic fiber layer may be in the form of a web or a nonwoven fabric made of elastic fibers. For example, it may be a web or a non-woven fabric formed by a spinning blow method, a spun bond method, a melt blow method, or the like. As the constituent fiber of the elastic fiber layer, for example, a fiber made of thermoplastic elastomer, rubber or the like can be used. In particular, fibers made from thermoplastic elastomers can be melt-spun using an extruder in the same way as ordinary thermoplastic resins, and the fibers thus obtained are easily heat-sealed. Is suitable for stretchable nonwoven fabrics.

  Examples of the thermoplastic elastomer include styrene elastomers such as SBS, SIS, SEBS, and SEPS, olefin elastomers, polyester elastomers, and polyurethane elastomers. These can be used individually by 1 type or in combination of 2 or more types.

  The inelastic fiber layer has extensibility but is substantially inelastic. As used herein, extensibility refers to the case where the constituent fiber itself is stretched, and even if the constituent fiber itself is not stretched, the two fibers that have been heat-sealed at the intersection of the fibers are separated from each other, or the fibers are heat-sealed. For example, the three-dimensional structure formed by a plurality of fibers may be structurally changed, the constituent fibers may be broken, and the entire fiber layer may be elongated.

  Examples of the fibers constituting the inelastic fiber layer include fibers made of polyethylene (PE), polypropylene (PP), polyester (PET or PBT), polyamide, and the like. The fibers constituting the inelastic fiber layer may be short fibers or long fibers, and may be hydrophilic or water repellent. Further, core-sheath type or side-by-side composite fibers, split fibers, irregularly shaped cross-section fibers, crimped fibers, heat-shrinkable fibers, and the like can also be used. These fibers can be used singly or in combination of two or more. The inelastic fiber layer can be a continuous filament or short fiber web or nonwoven.

  The stretchable sheet (b) will be described. This stretchable sheet is a laminate sheet in which substantially inelastic nonelastic fiber layers are laminated on both sides or one side of an elastic layer having elastic stretchability, and these are partially joined in a regular pattern. It can be obtained by stretching.

  This laminated sheet is manufactured as follows, for example. On the fiber web (first inelastic fiber layer) supplied from the card machine, an elastic fiber is supplied to form an elastic layer, on which another card machine or fiber web (second inelastic fiber layer) is formed. Fiber layer). The obtained laminated sheet having a three-layer structure is subjected to hot air treatment by an air-through dryer. The laminated sheet after the hot air treatment is subjected to hot embossing by an embossing device including an embossing roll in which embossing convex portions are regularly arranged on the peripheral surface and an anvil roll arranged to face the embossing roll. In addition, although the hot air process with a dryer is performed for the purpose of the heat | fever fusion | bonding of an elastic fiber and a non-elastic fiber, and the penetration | invasion of a fiber, this hot air process is also omissible.

  The elastic layer preferably includes elastic fibers made of an elastic material. Examples of the elastic material include a thermoplastic elastomer, rubber, ethylene / propylene copolymer, and the like. Among these, a thermoplastic elastomer is preferable because a fibrous elastic body can be formed relatively easily. Examples of the thermoplastic elastomer include polyurethane, styrene (SBS, SIS, SEBS, SEPS, etc.), olefin (copolymers such as ethylene, propylene, butene, etc.), vinyl chloride, and polyester. These can be used individually by 1 type or in combination of 2 or more types. The content of elastic fibers made of an elastic material in the elastic layer is preferably 50 to 100% by weight, particularly 75 to 100% by weight. As an elastic layer, it can replace with what consists of a fiber layer, and a film-like thing, a net-like thing, etc. can also be used. As the film or net forming material, the above-mentioned various elastic materials can be used.

  The stretchable sheet (4) will be described. As the elastic filament, for example, an elastic resin obtained by spinning an elastic resin spun from a spinning nozzle in a melted or softened state 1.1 to 400 times (more preferably 4 to 100 times) is used. be able to. Examples of the elastic resin include thermoplastic elastomers and rubbers. In particular, when a thermoplastic elastomer is used as a raw material, melt spinning using an extruder is possible in the same way as a normal thermoplastic resin, and the filament thus obtained is suitable because it can be easily heat-sealed to a nonwoven fabric. is there. Examples of the thermoplastic elastomer include various materials described as the elastic fiber material described above, and these can be used alone or in combination of two or more. A core-sheath type or side-by-side type composite fiber made of these resins can also be used. In particular, it is preferable to use a styrene-based elastomer, an olefin-based elastomer, or a combination thereof in terms of moldability, elastic properties, and cost of the elastic filament.

  The elastic filament is bonded to the nonwoven fabric in a substantially non-stretched state. As a mode of joining the elastic filament and the nonwoven fabric, for example, fusion, adhesion with an adhesive, or the like can be given. The elastic filaments are preferably bonded to the nonwoven fabric by fusion, and the elastic filaments are preferably bonded to these nonwoven fabrics while being sandwiched between two identical or different nonwoven fabrics. The nonwoven fabric to which the elastic filament is bonded can be extended in the same direction as the direction in which the elastic filament extends. Stretchable refers to the case where the constituent fibers themselves of the nonwoven fabric are stretched, and even if the constituent fibers themselves are not stretched, the fibers that are joined at the intersection point are separated from each other, or the fibers are joined by joining the fibers. This includes the case where the formed three-dimensional structure is structurally changed, the constituent fibers are broken, and the whole nonwoven fabric is elongated. The elastic filament preferably has a diameter of 10 to 200 μm, particularly 20 to 130 μm. The elastic filament is bonded to the non-woven fabric over its entire length. It does not require that all the fibers in contact with the elastic filament (component fibers of the non-woven fabric) are bonded to the elastic filament. In addition, it means that the elastic filaments and the constituent fibers of the nonwoven fabric are joined in such a manner that there is no intentionally formed non-joined part. Since the elastic filament is bonded to the nonwoven fabric over its entire length, the bonding force between the elastic strand and the nonwoven fabric can be sufficiently increased. As a result, even if the stretchable sheet is stretched, the elastic filament is difficult to peel from the nonwoven fabric. If the elastic filament is peeled from the nonwoven fabric, in the natural state (relaxed state), floating occurs between the elastic filament and the nonwoven fabric, and wrinkles are easily generated in the stretchable sheet.

  Next, the two non-stretchable sheets 13C and 12C constituting the exterior body 11 at the crotch will be described. The non-stretch sheet refers to a sheet having an elongation recovery rate (%) measured by the above [Method for measuring elongation recovery rate] of 20% or less, or a sheet that breaks before 100% elongation. The non-stretchable sheet may or may not have extensibility, but the maximum elongation is preferably 90% or less.

  As the non-stretch sheet, a nonwoven fabric, a laminated material of a nonwoven fabric and a resin film, a porous film, and the like are preferable. The non-stretch sheet is preferably formed from a nonwoven fabric made of thermoplastic fibers from the viewpoint of improving air permeability and texture, and is formed from a water-repellent nonwoven fabric from the viewpoint of preventing excrement leakage. Are preferred.

  Next, a pants-type disposable diaper according to another embodiment of the present invention will be described. About the diaper of other embodiment mentioned later, the point which is different from the diaper of 1st Embodiment is mainly demonstrated, and description is abbreviate | omitted about the same point. For the points that are not particularly described, the description of the first embodiment is applied as appropriate.

  In diaper 1 'of 2nd Embodiment, as shown in FIG. 8, inner layer sheet | seat 13A, 13B in the stomach side part A and the back side part B is the stomach side part A similarly to the diaper 1 of 1st Embodiment. From the crotch part C to the back side part B, it consists of one non-stretchable continuous sheet (inner continuous sheet) 13. On the other hand, the outer layer sheets 12A and 12B in the abdominal side A and the back side B are composed of one continuous sheet (outer continuous sheet) 12 extending from the abdominal side A through the crotch C to the back side B. And the exterior body 11 in the crotch part C has the structure by which the inner side continuous sheet 13 and the outer side continuous sheet 12 were laminated | stacked (the parts located in the crotch part C of both sheets 13 and 12 were laminated | stacked). . The portion 12C disposed on the crotch part of the outer continuous layer sheet 12 may be formed of an elastic sheet in the same manner as the portions 12A and 12B disposed on the abdominal side A and the back side B, or may not be stretched. May be. When the portion 12C is not stretched, the preferred length of the non-stretched portion 12C in the longitudinal direction of the diaper is the same as the length of the second non-stretchable sheet in the diaper 1 of the first embodiment. Examples of a method for non-stretching a part of the stretchable sheet include a method for making the stretch sheet substantially non-stretchable by heat treatment such as heat embossing.

  In the diaper 1 ′ of the second embodiment, at least one of the sheets 13 and 12 is melted and solidified over substantially the entire area of the absorbent main body arrangement region L10 extending from the abdominal side A through the crotch C to the back side B. Thus, a large number of melt-bonded portions 17 in which both are integrated are formed. The embossing pattern of the fusion bonding part 17 in the second embodiment is the same as the embossing pattern (see FIG. 6) in the first embodiment. Note that the sheets 13 and 12 are entirely joined by the adhesive 15 over the entire area. Also in the diaper of 2nd Embodiment, the effect similar to the diaper of 1st Embodiment is acquired.

  As mentioned above, although embodiment of this invention was described, this invention is not restrict | limited to said each embodiment, It can change suitably. For example, as shown in FIG. 9, in the pants-type disposable diaper of the present invention, the exterior body 11 in the crotch part C may be composed of only one non-stretchable sheet 13C. The crotch part C in this case is a part not covered with the outer layer sheets 12A and 12B. Moreover, the formation pattern of the fusion | melting junction part 17 in the absorptive main body arrangement | positioning area | region L10 can be made into another pattern instead of the formation pattern shown in FIG.

  The description omitted in one embodiment described above and the requirements of only one embodiment can be applied to other embodiments as appropriate, and the requirements in each embodiment can be appropriately changed between the embodiments. Can be substituted.

FIG. 1 is a perspective view showing a pants-type disposable diaper according to a first embodiment of the present invention. FIG. 2 is a plan view showing the skin contact surface side in the expanded and extended state of the disposable diaper shown in FIG. 1. 3 is a cross-sectional view taken along line II-II in FIG. FIG. 4 is an exploded perspective view of the disposable diaper shown in FIG. 1. FIG. 5 is a schematic diagram showing a cross section taken along line III-III in FIG. 2. FIG. 6 is a diagram showing sheets constituting the exterior body of the disposable diaper shown in FIG. 1 and their joining modes. FIG. 7 is a schematic view (partially enlarged view of FIG. 5 equivalent view) showing an example of the peripheral edge portion of the waist opening in the pants-type disposable diaper of the present invention. FIG. 8: is a figure (FIG. 5 equivalent figure) which shows the underpants type disposable diaper of 2nd Embodiment of this invention. FIG. 9 is a view (corresponding to FIG. 5) showing a pants-type disposable diaper according to still another embodiment of the present invention.

Explanation of symbols

1,1 'Pants-type disposable diaper 2 Top sheet 3 Back sheet 4 Absorbent core 5 Waist opening 6 Leg opening 10 Absorbent body 11 Exterior body 12A Outer layer sheet 12B in the abdominal side Outer layer sheet 12C in the back side Non-stretchable sheet 13A Inner layer sheet 13B in the ventral side portion Inner layer sheet 13C in the dorsal side portion First non-stretchable sheet 14 Joint portion between the outer layer sheet and the second non-stretchable sheet in the ventral side portion and the dorsal side portion 15 Adhesive 17 Melt Joint A Abdominal Side B Back Side C Crotch L10 Absorbent Body Arrangement Area

Claims (5)

An absorbent body including an absorbent core, and an exterior body positioned on the non-skin contact surface side of the absorbent body and fixing the absorbent body, and both side edges of the exterior body on the back side And a pants-type disposable diaper in which a pair of side seal parts, a waist opening part and a pair of leg opening parts are formed by joining both side edges of the exterior body in the ventral part,
The exterior body in each of the ventral part and the back part has a structure in which an outer layer sheet made of a stretchable sheet and an inner layer sheet made of a non-stretchable sheet are laminated, and the exterior body in the crotch part is a non-stretchable sheet Formed with
Between the outer layer sheet and the inner layer sheet in each of the ventral side portion and the back side portion, the absorptivity is bonded to the entire surface by an adhesive and overlaps with the absorbent main body in each of the ventral side portion and the back side portion . In the main body arrangement region, at least one of the outer layer sheet and the inner layer sheet is melted and solidified to form a melt bonded portion in which both are integrated ,
The said melt | fusion junction part is a pants type disposable diaper currently formed in a part of said absorptive main body arrangement | positioning area | region . The melt-bonded portion has a rectangular shape in plan view, and is formed in a large number in the absorbent main body arrangement region, and a large number of the melt-bonded portions are respectively aligned with the longitudinal direction of the diaper, The pants-type disposable diaper according to claim 1 , wherein a row is formed at a predetermined interval in the longitudinal direction of the diaper, and a row of the melt-bonded portions is arranged at a predetermined interval in the diaper width direction . The bonding strength between the outer layer sheet and the inner layer sheet in each of the ventral side portion and the back side portion is such that the side seal portion and the peripheral edge portion of the waist opening portion are closer to the side seal portion and the waist opening portion. The underpants type disposable diaper of Claim 1 or 2 larger than the part enclosed by the outer edge part of the diaper containing a peripheral part. The inner layer sheet in the ventral part and the dorsal part consists of a single non-stretchable continuous sheet extending from the ventral part through the crotch to the dorsal part, and the outer layer sheet in the ventral part and the dorsal part is , Consisting of separate elastic sheets,
The exterior body in the crotch is composed of the continuous sheet and a second non-stretchable sheet laminated on the non-skin contact surface side of the continuous sheet, and the front and rear ends of the second non-stretchable sheet are on the ventral side. The underpants type disposable diaper as described in any one of Claims 1-3 joined to the said outer layer sheet | seat in a part and a back side part. The inner layer sheet in the ventral part and the dorsal part is composed of a single non-stretchable inner continuous sheet extending from the ventral part through the crotch to the dorsal part, and the outer layer sheet in the ventral part and the dorsal part. Consists of a single stretchable outer continuous sheet that extends from the abdominal side through the crotch to the back side,
The underpants type disposable diaper as described in any one of Claims 1-3 in which the exterior body in a crotch part has the structure by which the said inner side continuous sheet and the said outer side continuous sheet were laminated | stacked.

Images