JP4834528B2 - Method for manufacturing absorbent article - Google Patents

Description

The present invention is an absorbent article using a surface sheet that is rich in three-dimensionality, has high cushioning properties, eliminates skin troubles by reducing the contact area with the skin, and has excellent shape retention of uneven embossing It relates to the manufacturing method .

  Conventionally, as a surface material of an absorbent article, an appropriate embossing pattern has been given according to various purposes such as reducing the contact area with the skin to suppress the moist feeling, or giving the texture and enhancing the touch. Things are offered to the market. As this kind of thing, the following patent documents 1 and 2 etc. can be mentioned, for example.

  In the following Patent Document 1, the surface material having an infinite number of hole portions, each of which has a convex curved surface, an infinite number of top portions not forming a continuous plane, an infinite number of bottom portions each having a concave curved surface, the top portion and the above-mentioned The surface material of the absorbent article which comprised the curved wall part which each connects a bottom part is disclosed.

Moreover, in the following Patent Document 2, the surface sheet has a large number of convex portions and concave portions, and at least the skin-facing surface is made of a nonwoven fabric, and at least at the top of the convex portions and / or in the vicinity thereof, there is an opening in the nonwoven fabric. An absorbent article in which is formed is disclosed.
JP-A-5-228173 JP 2002-238947 A

  However, in the case of the surface material described in Patent Document 1, the surface area of contact with the skin is certainly smaller than that of the planar surface material, and skin troubles such as rubbing, fogging and itching can be reduced. It was not enough.

  Further, in the case of the absorbent article described in Patent Document 2, at least the openings are formed in the nonwoven fabric at the tops and / or in the vicinity of the convex portions, so that the shape retention is not sufficient and the seats When the state of receiving pressure at the time of going to bed continues, there is a problem that the unevenness of the wavy processing gradually decreases. In addition, the liquid once absorbed from the opening portion reverted to the skin side, causing skin troubles such as stickiness, fogging and itching.

Therefore, the main problem of the present invention is to minimize the contact area with the skin, effectively prevent skin troubles such as rubbing, fogging and itching, improve the touch feeling, and eliminate the sticky feeling when absorbing body fluids, It is another object of the present invention to provide a method for manufacturing an absorbent article that can maintain a concave-convex shape continuously, not only in a dry state but also in absorbing a body fluid, by improving the shape retention of the concave-convex emboss.

In order to solve the above problems, as the present invention according to claim 1, an absorbent body is interposed between a liquid-permeable top sheet and a back sheet, and the top sheet is a nonwoven fabric layer constituting a skin contact surface layer. And a non-skin contact surface side of the non-skin contact surface of the non-skin layer, and a two-layered multi-layer sheet embossed with a hydrophilic second non-woven sheet overlaid on the back side of the top sheet the by applying a regular pattern, to form a large number of defined area which is defined as a mesh by embossing lines or embossing effect line to form a ridge which KakueNaru region projects outward, And in the manufacturing method of the absorbent article in which a hollow portion recessed inward is formed in the substantially central portion of each defined area ,
The second nonwoven fabric sheet is in a state in which a tension is applied to the surface sheet, and the surface sheet and the second nonwoven fabric sheet are heat-sealed in the recessed portion while the surface sheet and the second nonwoven fabric sheet are laminated. Thus, the manufacturing method of the absorbent article characterized by providing the said embossing is provided.

In the first aspect of the present invention, the second nonwoven fabric sheet is placed on the back side of the top sheet, and embossing is performed together with the top sheet while both sheets are in a laminated state. At this time, the second nonwoven fabric sheet is subjected to embossing in a state where tension is applied to the surface sheet, whereby the surface sheet shrinks after embossing and the embossed traces are clearly exposed.

In this absorbent article, by providing embossing in a regular pattern, a large number of defined areas defined in a mesh shape by embossed lines or embossed influence lines are formed, and each defined area is outward. form forms a raised portion which projects, and since the forming the recess to recess at a substantially central portion inward of each defined area, than merely a large number of ridges is provided, the contact area with the skin By reducing the size of the region where the skin is the strongest, it is possible to effectively prevent skin troubles such as rubbing, fogging and itching, and to improve the feeling of touch. In addition, the shape of the raised portion is enhanced by the inwardly recessed portion provided in the substantially central portion of the defined region, so that the uneven shape can be maintained continuously even when absorbing body fluids as well as in the dry state. become.

Further, the top sheet is a two-layered sheet comprising a non-woven fabric layer constituting a skin contact surface layer and a plastic film layer laminated on the non-skin contact surface side of the nonwoven fabric layer, Since the emboss is applied in a state where the hydrophilic second nonwoven fabric sheet is bonded to the back surface side of the sheet, body fluid from the recesses between the raised parts and the hollow part formed in the substantially central part of the defined area Absorption of body fluids can be done quickly, and there is no stickiness when absorbing body fluids, preventing skin problems such as fogging and itching.
Furthermore, in the said hollow part, the body sheet is smoothly absorbed into the second nonwoven fabric sheet in the hollow part without impairing the touch feeling by heat-sealing the top sheet and the second nonwoven sheet, There is no sticky feeling.

As described above in detail, according to the present invention, the contact area with the skin is minimized, skin troubles such as rubbing, fogging and itching are effectively prevented, the feeling of touch is improved, and the sticky feeling at the time of absorbing body fluid is eliminated. Further, by improving the shape retention of the embossed surface, it is possible to provide a method for producing an absorbent article that can maintain the uneven shape continuously even when absorbing a body fluid as well as a dry state.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a partially broken perspective view of a sanitary napkin 1 according to the present invention.

[Structure of absorbent article 1]
The sanitary napkin 1 is mainly used for applications such as panty liners, sanitary napkins, cage sheets, incontinence pads, and the like. For example, as shown in FIG. The absorbent body 4 or the absorbent body 4 surrounded by the crepe paper 5 is interposed between the liquid permeable top sheet 3 (hereinafter, simply referred to as a top sheet), as shown in FIG. A hydrophilic second sheet 6 is arranged between the sheet 3 and the absorber 4. Around the absorber 4, the liquid-impermeable back sheet 2 and the top sheet 3 are joined by an adhesive means such as a hot melt adhesive.

  The liquid-impervious back sheet 2 is made of a sheet material having at least water-impervious properties such as polyethylene and polypropylene, but in addition to this, a non-woven sheet after securing a substantially liquid-impervious property through a waterproof film. (In this case, a liquid-impervious back sheet is composed of the waterproof film and the nonwoven fabric). In recent years, those having moisture permeability tend to be suitably used from the viewpoint of preventing stuffiness. The water- and moisture-permeable sheet material is a microporous material obtained by melting and kneading an inorganic filler in an olefin-based resin such as polyethylene or polypropylene to form a sheet, and then stretching in a uniaxial or biaxial direction. A sheet is preferably used.

  As the surface sheet 3, a multilayer sheet having at least a nonwoven fabric layer constituting a skin contact surface layer and a plastic film layer laminated on the non-skin contact surface side of the nonwoven fabric layer is used, and embossing is regulated. By providing the target pattern, a large number of defined areas K, K... Defined by the embossed lines or the embossed influence lines are formed, and each defined area K, K. What forms the protruding part 7 and has the hollow part 8 recessed inward in the approximate center part of each said definition area | region K is used. The surface sheet 3 will be described in more detail later.

  The absorbent body 4 interposed between the liquid-impermeable back sheet 2 and the top sheet 3 is, for example, a mixture of a highly water-absorbent resin in pulp, or a mixture of chemical fibers in the pulp and a high water absorption. A material mixed with a conductive resin is used. As shown in the figure, it is desirable that the absorbent body 4 is surrounded by crepe paper 5 in order to maintain its shape and quickly diffuse menstrual blood and prevent reverse return of menstrual blood once absorbed. Examples of the pulp include chemical fibers obtained from wood, cellulose fibers such as molten pulp, and artificial cellulose fibers such as rayon and acetate. Softwood pulp having a longer fiber length than hardwood pulp functions and It is preferably used in terms of price.

  Examples of the superabsorbent resin include cross-linked polyacrylate, self-crosslinked polyacrylate, saponified acrylate-vinyl acetate copolymer cross-linked, isobutylene / maleic anhydride copolymer cross-linked, Examples include cross-linked polysulfonates, and partially cross-linked water-swellable polymers such as polyethylene oxide and polyacrylamide. Among these, those based on acrylic acid or acrylate that are excellent in water absorption and water absorption speed are preferred. In the production process of the highly water-absorbent resin having the water absorption performance, the water absorption force and the water absorption speed can be adjusted by adjusting the crosslinking density and the crosslinking density gradient. The content of the superabsorbent resin is desirably 1 to 60%. When the content of the superabsorbent resin is less than 1%, sufficient absorbability cannot be provided, and when it exceeds 60%, the entanglement between the pulp fibers disappears, the sheet strength decreases, and tears, cracks, etc. Is likely to occur.

In the present invention, as shown in FIG. 1, the mixing form of the superabsorbent resin can be changed between the case where the absorber 4 is flat with one layer and the case where the middle and high portions are formed in the region corresponding to the discharge port. desirable. That is, when the absorber 4 is flat, it is desirable to prevent the gel blocking phenomenon by unevenly distributing the highly water-absorbent resin so as to be distributed in a large amount on the lower layer side. In this case, it is desirable that the pulp basis weight of the absorbent body 4 is 70 g / m ² or more and the basis weight of the superabsorbent resin is 10 g / m ² or more. On the other hand, when the middle and high parts are formed in the absorbent body 4, in order to ensure the absorption performance in the middle and high parts, the basis weight of the middle and high part absorbent body is made larger than the basis weight of the peripheral part absorbent body. It is desirable that the basis weight of the middle and high parts is smaller than that of the peripheral part. Specifically, the basis weight of the middle and high parts is 200 g / m ² or more, the basis weight of other peripheral parts is 100 g / m ² or more, and the basis weight of the superabsorbent resin is 10 g / m ² or more as described above. preferable.

  The hydrophilic second nonwoven fabric sheet 6 disposed between the liquid-permeable surface sheet 3 and the absorbent body 4 only needs to be hydrophilic to the body fluid. Specifically, by using recycled fibers such as rayon and cupra, natural fibers such as cotton, the material itself has hydrophilicity, or synthesis of olefins such as polyethylene or polypropylene, polyesters, polyamides, etc. The fiber which surface-treated with the hydrophilizing agent and provided the hydrophilic property can be used. The second nonwoven fabric sheet 6 is placed on the back side of the top sheet 3 and is embossed together with the top sheet 3 with both sheets in a laminated state. At this time, the second nonwoven fabric sheet 6 is subjected to embossing in a state where tension is applied more than that of the top sheet 3, so that the top sheet 3 shrinks after embossing and the embossed traces are clearly exposed.

  It is desirable that the second nonwoven fabric sheet 6 and the absorbent body 4 are joined by a hot melt adhesive or the like on the lower surface of the second nonwoven fabric sheet 6, particularly at the embossed portion. By joining the second nonwoven fabric sheet 6 and the absorbent body 4, menstrual blood or the like can be quickly permeated into the absorbent body 4 from the embossed portion of the second nonwoven fabric sheet 6 and absorbed.

[Structure of surface sheet 3 and second non-woven sheet 6]
As shown in FIG. 2, the surface sheet 3 comprises a nonwoven fabric layer 3A constituting a skin contact surface layer and a plastic film layer 3B laminated on the non-skin contact surface side of the nonwoven fabric layer 3A. A multi-layered sheet of layers, and by providing embossing in a regular pattern, a large number of defined areas K, K... Defined in a mesh pattern by embossed lines or embossed influence lines are formed. A liquid-permeable sheet is used in which the region K forms a protruding portion 7 that protrudes outward and has a recess 8 that is recessed inwardly at a substantially central portion of each defined region K. Further, it is desirable to use a surface sheet 3 that has been subjected to a number of opening treatments.

  As shown in FIGS. 4, 6 and 7, the embossed line refers to an emboss of a continuous linear line or a discontinuous linear line of a broken line, and the embossed influence line is As shown in FIG. 5, by providing dot-like embossing in a regular pattern such as a regular pattern such as a lattice arrangement or a staggered arrangement, the line portion connecting the dot-like embosses is affected by the embossing. Says the hollow line produced by compression.

  Each of the defined areas K has a raised portion 7 that protrudes outward by an embossed line or an embossed influence line that surrounds the surrounding area, and a recessed portion 8 that is recessed inward at a substantially central portion of each defined area K. By being provided, the area of contact with the skin becomes smaller than that provided with a large number of raised portions, and by rubbing the substantially central portion (top) of the defined region that strikes the skin most strongly, rubbing, Skin troubles such as fogging and itching can be effectively prevented, and the feeling of touch can be improved. In addition, by providing a recess 8 that is recessed inwardly at the substantially central portion of each defined region K, the shape retention of the raised portion 7 can be improved, and the concave and convex shape can be improved not only in the dry state but also when absorbing bodily fluids. The skin trouble can be prevented by maintaining the skin continuously.

  Examples of the material fibers constituting the nonwoven fabric layer 3A include synthetic fibers such as polyethylene or polypropylene, synthetic fibers such as polyester and polyamide, recycled fibers such as rayon and cupra, and natural fibers such as cotton. In addition, a nonwoven fabric obtained by an appropriate processing method such as an air-through method, a spunlace method, a spunbond method, a thermal bond method, a melt blown method, or a needle punch method can be used. Among these processing methods, the spunlace method is excellent in terms of flexibility and the spunbond method is excellent in drapeability, and the air-through method and the thermal bond method are excellent in terms of being bulky and soft. The non-woven fiber may be either a long fiber or a short fiber, but preferably a short fiber is used in order to give a towel texture. In order to facilitate the embossing treatment, it is preferable to use an olefin fiber such as polyethylene or polypropylene having a relatively low melting point. In addition, a composite fiber such as a core-sheath fiber, a side-by-side fiber, or a split fiber having a fiber having a high melting point as a core and a fiber having a low melting point as a sheath can be suitably used.

  On the other hand, as the material of the plastic film layer 3B, for example, olefin resins such as polyethylene and polypropylene, polyamide resins such as polyester and nylon, ethylene-vinyl acetate copolymer (EVA), and the like can be preferably used. .

  In the embossing treatment, as shown in FIG. 2, the nonwoven fabric layer 3A constituting the skin contact surface layer and the plastic film layer 3B laminated on the non-skin contact surface side of the nonwoven fabric layer 3A are 2 After the surface sheet 3 consisting of a multilayered sheet of layers alone or with the second nonwoven fabric sheet 6 overlaid on the back side thereof, a number of aperture treatments (not shown) are performed, and then shown in FIG. As described above, the embossing M is given to the top sheet 3 in a regular pattern such as various lattice-shaped linear patterns, lattice arrangements, or staggered dot patterns. A plurality of defined regions K, K... Are formed, and each defined region K forms a protruding portion 7, 7... Projecting outward, and substantially at the center of each defined region K. By embossing So as to form a recess 8 recessed inward.

  By embossing the surface sheet 3 and the hydrophilic second nonwoven sheet 6 in an overlapped state, menstrual blood or the like is easily absorbed by the absorbent body 4 via the second nonwoven sheet 6, and the surface is sticky. As well as the feeling disappears, there is no reversal of the body fluid once absorbed, and a smooth feeling can be maintained, and skin troubles such as skin fogging and itching can be effectively prevented.

  Moreover, in the said hollow part 8, it is desirable that the said surface sheet 3 and the said 2nd nonwoven fabric sheet 6 are heat-seal | fused. The surface sheet 3 and the second nonwoven fabric sheet 6 are heat-sealed in the dent 8 so that the body fluid is smoothly absorbed into the second nonwoven fabric sheet 6 in the dent 8 without impairing the feeling of touch. The feeling of sticking disappears.

  The embossing pattern for forming the defined area K can be applied in various forms in plan view as shown in FIGS. FIG. 4 is an example in which the defined region K is defined by the embossed lines 9 provided in the shape of a rhombus lattice, and the raised portions 7 of the topsheet 3 and the recessed portions by the embossed lines 9 can be clearly distinguished. Is. FIG. 5 is an example in which dot embosses 10 are given only to the portions corresponding to the intersections of the rhombic lattice embosses of FIG. 4, and the line portions connecting the dot embosses 10, 10 are affected by the emboss 10. The defined area K is defined by the hollow lines 11, 11... Generated by compressing (pulling) 3. In this way, by providing the emboss 10 only at the intersection and forming the defined region K by the indentation-affected line due to the emboss 10, it is possible to obtain a soft touch as a whole and to improve the texture. FIG. 6 is an example in which embossed lines 12, 12,... Are provided in broken lines so that the embossed lines are discontinuous at each intersection of the rhombus lattice of FIG. Since it does not have, it can prevent that a sheet | seat becomes hard and has an effect which can make a touch feeling soft. 7 is an example in which the rhomboid embossed lines 13, 13... In FIG.

  Each of the defined regions K is a rhombus in the illustrated examples of FIGS. 4 to 7, but as shown in FIG. 8, (A) a square, (B) a triangle, (C) a pentagon, (D) a hexagon. It is possible to use any shape such as a polygon such as (E) a circle or an ellipse.

  On the other hand, the shape of the recess 8 in plan view is circular in the illustrated example, but it can be formed in an arbitrary shape such as an arbitrary polygon such as a triangle, a quadrangle, a pentagon, and a hexagon, or an ellipse.

In addition, the planar area of the recess 8 is such that a large number of opening treatments (detailed later) are applied to the topsheet 3 so that body fluid can be quickly permeated from the topsheet 3 to the inside. In order to reliably form the depressions 8, 8, and to sufficiently exhibit the above-described effects of the depressions 8, it is preferable to make the area of the planar shape of the depressions 8 larger than the aperture area of the topsheet 3. . Specifically, the area of the planar shape of the recess 8 is 0.5 mm ² or more, preferably 0.6 mm ² or more. Moreover, in order to prevent the body fluid from returning, the formation rate on the top sheet 3 is preferably 10 pieces / cm ² or less. Note that a plurality of the recessed portions 8 may be provided for one defined region K.

Apertures formed in the topsheet 3, ² opening area per the 0.20～0.60Mm, preferably a 0.47～0.54Mm ^2, opening ratio 10-30%, preferably Is preferably formed at a ratio of 11 to 20%. When the aperture area is less than 0.20 mm ² , the aperture area is too small and body fluid stays in the aperture wall. In addition, when the aperture area exceeds 0.60 mm ² , body fluid reverses through the aperture, which is not preferable. On the other hand, when the open area ratio is less than 10%, the open area ratio is too small and the body fluid discharged to the surface cannot be quickly transmitted. In addition, when the hole area ratio exceeds 30%, the bodily fluid reverts, which is not preferable.

  In order to form the openings, the plastic film layer 3B is softened to near the softening temperature and is positioned on the upper surface of the support having a large number of openings, and is sucked from below the support. For example, a method of forming a hole by pressurizing with air pressure from the upper surface of the wire, a method of piercing a heating needle, or the like can be employed. In addition, the opening process may be performed after the nonwoven fabric layer 3A and the plastic film layer 3B are laminated, and the openings may be formed in all the laminated layers, but at least for the plastic film layer 3B. It only has to be made. In the opening process in this case, after the opening is formed in the plastic film layer 3B, the nonwoven fabric layer 3A is laminated.

It is a partially broken perspective view of the absorbent article 1 according to the present invention. It is a figure which shows the base-material cross-section structure (before embossing) of the liquid-permeable surface sheet 3 and the 2nd nonwoven fabric sheet 6. FIG. It is a figure which shows the base-material cross-section structure (after embossing) of the liquid-permeable surface sheet 3 and the second nonwoven fabric sheet 6. It is an enlarged plan view of the liquid-permeable surface sheet 3 which shows an emboss pattern (the 1). It is an enlarged plan view of the liquid-permeable surface sheet 3 which shows an emboss pattern (the 2). It is an enlarged plan view of the liquid-permeable surface sheet 3 which shows an emboss pattern (the 3). It is an enlarged plan view of the liquid-permeable surface sheet 3 which shows an emboss pattern (the 4). 3 is an enlarged plan view of a liquid-permeable surface sheet 3 showing the shape of a defined region K. FIG.

  DESCRIPTION OF SYMBOLS 1 ... Absorbent article (sanitary napkin), 2 ... Impervious back sheet, 3 ... Impervious surface sheet, 4 ... Absorber, 5 ... Crepe paper, 6 ... Second sheet, 7 ... Raised part, 8 ... Recessed part, K ... defined area

Claims (1)

An absorbent body is interposed between the liquid-permeable top sheet and the back sheet, and the top sheet is laminated on the non-skin contact surface side of the nonwoven fabric layer constituting the skin contact surface layer. Embossed line or embossed influence line by providing a regular pattern with embossing in a state where a hydrophilic second non-woven sheet is overlapped on the back side of the top sheet, which is a double-layer sheet composed of a plastic film layer In addition to forming a large number of defined areas defined in a mesh shape, each defined area forms a protruding portion protruding outward, and is recessed inward at a substantially central portion of each defined area. In the manufacturing method of the absorbent article in which the depression is formed,
The second nonwoven fabric sheet is in a state in which a tension is applied to the surface sheet, and the surface sheet and the second nonwoven fabric sheet are heat-sealed in the recessed portion while the surface sheet and the second nonwoven fabric sheet are laminated. Thus, the manufacturing method of the absorbent article characterized by providing the said embossing.

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