JP6881282B2 - Composite sheet and its manufacturing method and absorbent articles using it - Google Patents

Description

The present invention relates to a composite sheet having a bubble chamber formed on its surface, a method for producing the same, and an absorbent article using the composite sheet as a liquid-permeable top sheet.

Various absorbent products such as diapers for children or adults, sanitary napkins for women, light and moderate incontinence pads, excretion treatment products for pets, etc., with an absorber interposed between the liquid permeable top sheet and back sheet. Are known. In such an absorbent article, by forming a bubble chamber in the top sheet that comes into direct contact with the wearer's skin, the contact area between the wearer's skin and the top sheet is reduced at the same time as improving the feel of the top sheet. Those intended to improve breathability have been proposed. For example, Patent Document 1 discloses that the top sheet is composed of two upper and lower films, an uneven pattern is formed on the upper film, and the concave portions of the upper film are joined to a smooth lower film. In such a top sheet, a large number of bubble chambers such as a bubble buffer member are formed between the convex portion of the upper film and the lower film, and the cushioning property can be enhanced.

JP-A-2009-50538 Japanese Unexamined Patent Publication No. 2016-138358

In the top sheet of a conventional absorbent article in which a bubble chamber is formed by using two films, the joint region between the concave portion of the upper film and the lower film is heat-sealed, and as a result, the liquid permeability of this joint portion is lowered. Have a tendency to. For this reason, liquid matter such as urine that flows into the recesses of the upper film may not flow smoothly from the upper film of the top sheet to the lower film to the absorber. In order to solve such a problem, Patent Document 2 discloses a technique in which an opening is formed in a joint portion of the upper film and the lower film by using a needle at the time of joining.

However, when a hole is made in the joint portion between the upper film and the lower film using a needle as disclosed in Patent Document 2, a part of the needle may be mixed into the product due to a needle breakage accident. Therefore, it is necessary to constantly monitor the presence or absence of breakage of the needle during the manufacture of the top sheet, which increases the cost. Further, when a hole is made in the top sheet with a needle, it is necessary to heat the needle to melt the top sheet, so that the opening formed by the needle becomes hard and the texture of the top sheet is deteriorated.

An object of the present invention is a composite sheet capable of forming a bubble chamber using two films and maintaining good liquid permeability at a joint portion between the two films without deteriorating the texture, and a method for producing the same. An object of the present invention is to provide an absorbent article using this composite sheet.

The first embodiment of the present invention comprises a first film in the form of a liquid-permeable sheet in which a large number of recesses arranged at predetermined intervals are formed, and the first film which is superposed on the first film. A composite sheet including a second film in the form of a liquid-permeable sheet bonded to the bottom surface of the recess, and each recess is a first along the longitudinal direction of the first film. A groove-shaped first recess extending in the direction, a groove-shaped second recess extending in a second direction different from the first direction along the longitudinal direction of the first film, and these. It is characterized in that it has an intersecting region where the first and second recesses overlap, and an opening is formed in contact with the intersecting region.

In the present invention, an opening is formed in contact with the intersecting region of the groove-shaped first and second recesses of the first film, respectively, and the liquid is transmitted through the first and second films. In addition, it also passes through this opening.

In the composite sheet according to the first embodiment of the present invention, the area of each opening is from 0.19 mm ² (corresponding to a diameter of about 0.5 mm) to 1.77 ^{mm 2} (corresponding to a diameter of about 1.5 mm). It is preferably in the range of up to.

A second embodiment of the present invention includes a step of transporting the first long film in the longitudinal direction at a first speed, and during the transport of the first long film to the first long film. A step of forming a large number of recesses arranged at predetermined intervals, a step of transporting a second long film in the longitudinal direction at the first speed, and a step of forming the recesses formed in the first long film. A step of joining the bottom surface of the recess of the first long film and the second long film during these transportation so that the bottom surface and the second long film overlap each other, and the step of joining the second long film after joining. The first and second long films are conveyed at a second speed faster than the first speed, and reach the joint portion between the bottom surface of the recess of the first long film and the second long film. A method for producing a composite sheet, which comprises a step of forming an opening by stretching and breaking.

In the method for producing a composite sheet according to the second embodiment of the present invention, the individual recesses are the groove-shaped first recesses extending in the first direction along the longitudinal direction of the first long film. , A groove-shaped second recess extending in a second direction different from the first direction along the longitudinal direction of the first long film, and an intersecting region where these first and second recesses overlap. An opening may be formed by stretching fracture due to stress concentration generated in this intersecting region.

Further, it is preferable that the second speed is in the range of 1.4 times to 1.9 times the first speed.

Similarly, the area of the individual openings ^{preferably ranges from 0.19 mm 2} (corresponding to a diameter of approximately 0.5 mm) to 1.77 ^{mm 2} (corresponding to a diameter of approximately 1.5 mm).

A third embodiment of the present invention comprises a liquid-impermeable back sheet, an absorber to be superposed on the back sheet, and an absorber to be superposed on the back sheet with the absorbent body interposed therebetween. It is an absorbent article characterized by comprising a top sheet made of a composite sheet or a top sheet made of a composite sheet produced by the method according to the second aspect of the present invention.

According to the composite sheet of the present invention, the openings are formed in contact with the intersecting regions where the groove-shaped first and second recesses extending in different directions along the longitudinal direction of the first film overlap each other. The liquid can pass through the opening.

If the area of each opening is in the range from 0.19 mm ² to 1.77 mm ^2, it is possible to pass the liquid product efficiently.

According to the method for producing a composite sheet of the present invention, an opening is formed by stretching failure at the joint portion between the bottom surface of the recess of the first long film and the second long film. There is no need to use needles for forming, and there is no need to monitor broken needles.

When the opening due to stretch fracture is formed by the stress concentration generated in the intersection region, the position and size of the opening can be adjusted more accurately.

If you set the second speed in the range of 1.4 times the first speed to 1.9 times, the range of the area of each opening easily from 0.19 mm ² to 1.77 mm ² be able to.

According to the absorbent article of the present invention, the top sheet made of the composite sheet of the present invention or the top sheet made of the composite sheet produced by the method of the present invention is provided, so that good liquid permeability and texture are provided. be able to.

It is a stereoscopic projection drawing which shows typically the appearance of one Embodiment which applied the absorbent article by this invention to a pants-type disposable diaper. It is a partially broken plan view of the state in which the closed portion of the embodiment shown in FIG. 1 is broken and unfolded. It is a three-dimensional projection drawing which disassembled the diaper in the unfolded state shown in FIG. It is sectional drawing which follows the IV-IV arrow view in FIG. It is sectional drawing which extracted and enlarged the part of the absorber in the embodiment shown in FIG. It is a plan view which extracted and enlarged a part of the top sheet in the absorber shown in FIG. It is sectional drawing which follows the arrow | view of VII-VII in FIG. It is a conceptual diagram which shows typically the manufacturing process of the top sheet shown in FIG. It is a top view which shows the appearance of another Example of the top sheet shown in FIG. FIG. 5 is a cross-sectional view taken along the line of arrow XX in FIG.

An embodiment in which the absorbent article according to the present invention is applied to a pants-type disposable diaper will be described in detail with reference to FIGS. 1 to 10. However, the present invention is not limited to such an embodiment, and any modification or modification included in the concept of the present invention described in the claims can be made.

The appearance of the pants-type diaper according to the present embodiment is shown in FIG. 1, and the appearance in a state where the closed portion is broken and the skin contact surface side is turned upside down is shown in FIG. 2, which is further disassembled. The appearance of the state is shown in FIG. 3, and the cross-sectional structure along the IV-IV arrow in FIG. 2 is schematically shown in FIG.

That is, the pants-type disposable diaper 10 in the present embodiment includes a front body cover sheet 11F, a back body cover sheet 11R, a back sheet 12, an absorber 13, a top sheet 14, and a pair of left and right side seats 15. , With a waist circumference seat 16.

The liquid-impermeable front body cover sheet 11F and the back body cover sheet 11R in the present embodiment correspond to the front body area and the back body area of the pants-type diaper (hereinafter, simply referred to as a diaper) 10 respectively. .. These cover sheets 11F and 11R are composed of an outer film 11o and an inner film 11i that are bonded to each other, but are not limited thereto. Further, it is also possible to integrally form these through the inseam region, and the present invention is not limited to this embodiment. Between the outer film 11o and the inner film 11i that are overlapped with each other, a rubber thread 17 for improving the fit when worn is extended in parallel with each other along the waist circumference opening 10w of the diaper 10. Many are distributed. These rubber threads 17 are integrated with the front body cover sheet 11F and the rear body cover sheet 11R, respectively. With these rubber threads 17, waist gathers 17g are formed in the waist circumference opening 10w of the diaper 10. The rubber threads 17 are not interposed in the regions of the cover sheets 11F and 11R on which the absorbers 13 are overlapped, so that a compressive force in the width direction does not act on the absorbers 13.

The outer film 11o and the inner film 11i described above can be formed of a polyolefin spunbonded non-woven fabric or the like, but other well-known materials can be appropriately adopted depending on the purpose.

Inside the front body cover sheet 11F and the back body cover sheet 11R, that is, the inner film 11i, both side portions of the pair of side sheets 15 in the longitudinal direction (vertical direction in FIG. 2), that is, the front body portion and the back body portion are provided. They are overlapped and each is integrally joined. Further, the front body portion and the back body portion of the back sheet 12 in which both side portions in the width direction (horizontal direction in FIG. 2) are overlapped on the pair of side seats 15 are overlapped on the front body cover sheet 11F and the back body cover sheet 11R. , Are integrally joined with these. In other words, the cover sheets 11F and 11R do not exist in the inseam region of the diaper 10 in the present embodiment, and the inseam portions of the pair of side seats 15 and the back seat 12 are exposed.

The portion of the absorbent main body 18 composed of the back sheet 12, the absorber 13 and the top sheet 14 shown in FIG. 2 is extracted and enlarged, and is shown in FIG. A liquid-permeable top sheet 14 is superposed on the liquid-impermeable back sheet 12, an absorber 13 is arranged between the back sheet 12 and the top sheet 14, and the peripheral edge of the top sheet 14 is an absorber. It is joined to the back sheet 12 so as to surround the 13.

The liquid-impermeable side sheet 15 in the present embodiment is free to have a first folded portion 15a defining the outer edge in the width direction and a second folded portion 15b defining the inner edge in the width direction. It has a third folded portion 15c that defines the edges. The other end in the width direction of the side sheet 15 whose one end side in the width direction is overlapped with the back sheet 12 is overlapped with the end portion in the width direction of the top sheet 14 and integrally joined to the top sheet 14 to form a three-dimensional gather 19g. The standing line 15d of the above is defined. A plurality of (three in the illustrated example) thread rubbers 20 are arranged in an extended state between the widthwise side end of the back sheet 12 and the side sheet 15 and in the first folded-back portion 15a, and an opening around the leg is provided. 20g of leg gathers are defined at 10t to improve the fit around the legs of the wearer. Further, at the free end of the side sheet 15, that is, in the immediate vicinity of the third folded-back portion 15c, a plurality of (three in the illustrated example) thread rubbers 19 for defining the three-dimensional gathers 19g are arranged in an elongated state. ing. At both ends of the side sheet 15 in the longitudinal direction, the side sheets 15 between the first folded portion 15a and the second folded portion 15b and between the second folded portion 15b and the third folded portion 15c are mutually formed. It is joined to the top sheet 14 in a superposed state.

The side sheet 15 described above can be formed of a polyolefin spunbonded non-woven fabric or the like, or the back sheet 12 can be formed of a polyethylene film having breathability, but other well-known materials are used for the purpose. It can be adopted as appropriate according to the above.

The absorber 13 in the present embodiment has a front body portion, an inseam portion, and a back body portion corresponding thereto so as to reach the back body region from the front body region of the diaper 10 through the inseam region. A pair of arcuate recesses 13c are formed in the inseam portion of the absorber 13, and the width of the inseam portion is narrower than the width of the front body portion and the back body portion, but the width of the inseam portion is not limited to this. The absorber 13 is composed of a sheet-shaped absorbent core 13a and a poorly water-soluble core coating material for wrapping the absorbent core 13a and preventing it from losing its shape, that is, a core wrap 13b. The absorbent core 13a contains fluffy pulp, that is, cellulosic water-absorbent fibers, SAP as a polymer-absorbing member, and the like. The core wrap 13b is composed of a non-woven fabric or tissue having a basis weight of 30 g / m ^{2 or less, but is not limited thereto.}

A part of the top sheet 14 shown in FIG. 5 is extracted and enlarged, and is shown in FIG. 6, and the cross-sectional structure along the arrow VII-VII is schematically shown in FIG. The top sheet 14 as a composite sheet in the present invention is composed of a sheet-like upper film 21 in which a large number of uneven patterns arranged at predetermined intervals are formed, and a smooth lower film 22 superimposed on the upper film 21. Has been done. The bottom surface of the recess 21d of the upper film 21 and the lower film 22 are integrally joined to form the top sheet 14. A large number of bubble chambers 14c are formed between the convex portion 21s of the upper film 21 and the lower film 22, and although the individual bubble chambers 14c are continuous in this embodiment, they can be configured independently. .. The uneven pattern formed on the upper film 21 in the present embodiment is the same as that described in FIG. 3 and the like in Japanese Patent Application Laid-Open No. 2016-137145, and the bottom surface of the concave portion 21d of the upper film 21 is shaded in FIG. It is shown by. That is, the concave portion 21d in the present embodiment includes a first concave portion 21d ₁ having an arc groove shape, and a _second concave portion 21d 2 having an arc groove shape opposite to _{the first concave portion 21d 1 having an arc groove shape.} The first and second recesses 21d ₁ and 21d ₂ have an intersecting region 21d _{C on} which they overlap. The first recess 21d ₁ extends in the first direction along the longitudinal direction of the upper film 21, and the second recess 21d ₂ is different from the first direction along the longitudinal direction of the upper film 21. It extends in the second direction. The top sheet 14 is formed with openings 23 in contact with _{the intersecting regions 21d C of the upper film 21.} The area of the individual openings 23 should range ^{from 0.19 mm 2 , which corresponds approximately 0.5 mm in diameter, to 1.77 mm 2,} which corresponds approximately 1.5 mm in diameter. It is preferable in that it enables smooth penetration of the liquid material flowing into the absorber 13.

The upper film 21 and the lower film 22 constituting the top sheet 14 can be formed of a liquid-permeable material such as a woven fabric, a non-woven fabric, or a porous film, but it is particularly preferable to use a non-woven fabric. Further, known non-woven fabrics manufactured by any method such as an air-through method, a heat bond method, a spunbond method, a melt blown method, a spunlace method, and a needle punch method can be used. However, from the viewpoint of workability of the opening 23, it can be said that it is preferable to include at least one of PP, PE / PET and PE / PP. In this embodiment, a polyolefin / polyester non-woven fabric is used as the upper film 21 and the lower film 22. Further, the thickness of each of the upper film 21 and the lower film 22 is preferably in the range of 0.3 mm to 2.0 mm from the viewpoint of the liquid permeability and texture of the top sheet 14 and the workability of the opening 23.

The waist circumference sheet 16 in the present embodiment is formed of a liquid-impermeable polyolefin non-woven fabric manufactured by the spunbond method, but a liquid-impermeable polyolefin non-woven fabric manufactured by the air-through method can also be used. Is. Further, the waist circumference sheet 16 is arranged along the waist circumference opening 10w of the diaper 10, but the present invention is not limited to this. The waist circumference sheet 16 is joined to the inner films 11i of the cover sheets 11F and 11R so as to cover both ends of the upper films 21 of the side sheets 15 and the top sheet 14 in the longitudinal direction.

The concept of an example of the manufacturing apparatus for the top sheet 14 as described above is schematically shown in FIG. This manufacturing apparatus includes a first film roll (not shown) around which a long upper film 21E is wound, and a second film roll (not shown) around which a long lower film 22E is wound. Further, the female molding roll 24 and the male molding roll 25 for forming a predetermined uneven pattern on the long upper film 21E, and the upper film 21E and the lower film 22E cooperate with the female molding roll 24. It is equipped with a flat roll 26 for joining. Further, a winding roll (not shown) for winding the manufactured long top sheet 14E and a pair of forming rolls 24, 25 and a flat roll 26 are synchronously driven and rotated together with the first and second film rolls. It has means. In addition to these, a winding means for driving and rotating the winding roll, a control device for controlling the operation of these synchronous driving means and the winding means (none of which are shown), and the like are provided, and the main part is composed of these. There is.

An uneven pattern corresponding to the shape of the bubble chamber 14c formed on the upper film 21E is formed on the outer peripheral surface of the male molding roll 25, and the outer peripheral surface of the female molding roll 24 is formed on the outer peripheral surface of the male molding roll 25. An uneven pattern complementary to the surface is formed. The rotation phase of the male molding roll 25 and the female molding roll 24 is such that the pair of molding rolls 24, 25 rotate synchronously, and the uneven patterns of the molding rolls 24, 25 mesh with each other at these meshing positions. , The distance between these axes is set appropriately. A well-known air suction system (not shown) for bringing the upper film 21E into close contact with the outer peripheral surface of the female molding roll 24 is incorporated in the region of the female molding roll 24 around which the long upper film 21E is wound. Further, a heating element 27 is arranged on the outermost peripheral portion of the female molding roll 24 for molding the bottom surface of the recess 21d formed in the upper film 21E (this corresponds to the region shown by the diagonal line in FIG. 6). There is.

A long lower film 22E unwound from the second film roll is wound around the flat roll 26 at a transport speed substantially the same as that of the long upper film 21E. The flat roll 26 has an appropriate contact pressure with the outermost peripheral surface of the female molding roll 24, that is, the portion where the heating element 27 is arranged, with the outer peripheral surface sandwiching the joint portion between the upper film 21E and the lower film 22E. It is arranged so that it will be transferred at.

Upper film 21E long drawn out from the first film roll is fed by the first conveying speed _{V 1} (e.g., every minute 100M～400m) between a pair of forming rolls 24, 25 described above, the female mold It is deformed so as to adhere to the uneven pattern on the surface of the roll 24. On the other hand, the lower film 22E long fed out of the second film roll, the outermost periphery of the first conveying speed V _{1 (strictly} female forming roll 24 between the female forming roll 24 and the flat roll 26 It is sent at almost the same speed as the peripheral speed of the part). Then, the lower film 22E wound around the flat roll 26 and the molded upper film 21E pass between the flat roll 26 and the female molding roll 24. During this time, the bottom surface of the recess 21d of the upper film 21E and the lower film 22E are heated by a heating element 27 having a surface temperature of 130 ° C. to 150 ° C., softened (partially melted), and integrally bonded to the second. of going to be taken up by the take-up roll in the conveying speed V _2. Here, the transport speed V ₂ on the exit side is set to 1.4 to 1.9 times the transport speed V ₁ on the entry side (140 m to 760 m / min in the above example), and after joining an appropriate tension. Give to the top sheet 14 of. Thus, the joint portion between the bottom surface and the lower film 22E of the concave portion 21d of the upper film 21E, by stretching destruction that occurs particularly intersection region 21d _C a large stress concentration occurs, the area of the range of 0.19mm ² ~1.77mm ² The opening 23 having a structure can be formed in the top sheet 14.

_{As described above, details of the first and second recesses 21d 1} , 21d ₂ formed in the top sheet 14 in the present embodiment are disclosed in Japanese Patent Application Laid-Open No. 2016-137145 and the like. Not limited. Any shape of the top sheet 14 in which a stand-alone or continuous bubble chamber is formed between the films 21 and 22 by joining the bottom surface of the recess 21d of the upper film 21 and the lower film 22. It does not matter if it is a concave portion of. However, in order to improve the reproducibility of the opening 23, it is effective to cause stretch fracture due to stress concentration generated at a specific portion of the joint portion due to the tensile force generated during winding of the top sheet 14. Therefore, it is effective to set the shapes of the first and second recesses 21d ₁ and 21d ₂ and the intersecting region 21d _{C in} which they overlap as the formation position of the opening 23.

For example, the joint portion of the top sheet 14 according to another embodiment of the present invention is schematically shown in FIG. 9, and the XX arrow cross-sectional structure thereof is schematically shown in FIG. The first recess 21d ₁ in the present embodiment has a linear shape inclined in the first direction with respect to the longitudinal direction of the top sheet 14 (vertical direction in FIG. 9), and the second recess 21d ₂ is the first. It forms a straight line that is inclined with respect to the longitudinal direction of the top sheet 14 (vertical direction in FIG. 9) in the direction opposite to the direction of. That is, the bubble chamber 14c partitioned in a grid pattern by the first and second recesses 21d ₁ and 21d ₂ is defined between the lower film 22 and the upper film 21. Therefore, stretch fracture occurs due to stress concentration in the intersecting region 21d _C where the first and second recesses 21d ₁ , 21d _{2 overlap, and the opening 23 can be formed.} However, as described above, by appropriately changing the materials and thicknesses of the upper film 21 and the lower film 22 constituting the top sheet 14, the joining temperature and the magnitude of the tension, etc., the opening 23 is crossed with the intersecting region 21d. It is possible to form other than _C.

Further, the absorbent article according to the present invention is not limited to the pants-type disposable diaper 10 described above, and can be applied to various absorbent articles such as a tape-type disposable diaper and a urine leak pad. For example, when the present invention is applied to a urine leak pad, the above-mentioned absorbent body 18 can be used as it is as a urine leak pad, that is, an absorbent article.

As described above, the present invention should be construed only from the matters described in the claims, and even in the above-described embodiment, the matters described by all the changes and modifications included in the concept of the present invention. Other than that is possible. That is, all the matters in the above-described embodiment are not for limiting the present invention, and may be arbitrarily changed according to the use, purpose, etc., including the configuration not directly related to the present invention. It is a thing.

10 Pants-type disposable diapers (diapers)
12 Backsheet 13 Absorber 14 Topsheet 14E Long Topsheet 14c Bubble Chamber 18 Absorbent Body 21 Upper Film 21E Long Upper Film 21d Recess 21d ₁ First Recess 21d ₂ Second _{Recess 21d C} Crossing Area 21s Convex part 22 Lower film 22E Long lower film 23 Opening V ₁ First transfer speed V ₂ Second transfer speed

Claims (7)

A first film in the form of a liquid-permeable sheet in which a large number of recesses arranged at predetermined intervals are formed, and
A composite sheet including a second film in the form of a liquid-permeable sheet that is superposed on the first film and joined to the bottom surface of the recesses of the first film, and the individual recesses are ,
A groove-shaped first recess extending in the first direction along the longitudinal direction of the first film, and
A groove-shaped second recess extending in a second direction different from the first direction along the longitudinal direction of the first film,
A composite sheet having an intersecting region where the first and second recesses overlap each other, and an opening is formed in contact with the intersecting region. Composite sheet according to claim 1 in which the area of each of the opening and lies in the range from 0.19 mm ² to 1.77 mm ^2. A step of transporting the first long film in the longitudinal direction at the first speed, and
During the transportation of the first long film, a step of forming a large number of recesses arranged at predetermined intervals in the first long film, and
A step of transporting the second long film in the longitudinal direction at the first speed, and
The bottom surface of the recess of the first long film and the second long film are formed so that the bottom surface of the recess formed in the first long film and the second long film overlap each other. The steps to join during these transports and
The first and second long films after joining are conveyed at a second speed faster than the first speed, and the bottom surface of the recess of the first long film and the second long film are formed. A method for producing a composite sheet, which comprises a step of forming an opening by stretching failure at a joint portion of the film. The individual recesses are a groove-shaped first recess extending in a first direction along the longitudinal direction of the first elongated film, and a groove-shaped first recess extending along the longitudinal direction of the first elongated film. It has a groove-shaped second recess extending in a second direction different from the direction of 1, and an intersecting region where these first and second recesses overlap, and the opening due to the stretching fracture is the intersecting region. The method for producing a composite sheet according to claim 3, wherein the composite sheet is formed by stress concentration generated in. The method for producing a composite sheet according to claim 3 or 4, wherein the second speed is in the range of 1.4 times to 1.9 times the first speed. Composite sheet manufacturing method according to any one of claims 3 to claim 5 in which the area of each of the opening and lies in the range from 0.19 mm ² to 1.77 mm ^2. A step of superimposing the liquid impermeable absorber back sheet of,
請Motomeko 1 or topsheet by composite sheet according to claim 2, or the top sheet by a composite sheet produced by the method described in any one of claims 3 to claim 6, wherein method of manufacturing an absorbent article, characterized in that it comprises the steps of superimposing on the backsheet across the absorber.

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