JP5133639B2 - Absorbent articles - Google Patents

Description

  The present invention relates to an absorbent article that enhances the diffusibility and absorbability of liquid in a surface sheet, effectively prevents the return of bodily fluids, is rich in three-dimensional effects, and has high cushioning properties.

  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.

  For example, in Patent Document 1 below, a large number of ridges and groove portions are alternately arranged so as not to have a flat surface portion, the ridge portions are curved in a convex shape, and the groove portions are curved in a concave shape, An absorbent article using a nonwoven fabric having a large number of apertures arranged at intervals as the groove is used as a top sheet is disclosed.

  However, when unevenness is formed on the top sheet, the adhesion with the body fluid absorbent member disposed on the lower surface side is lowered, and thus a new problem arises that menstrual blood diffusibility and absorbability are lowered. . In view of this, a technique has been proposed in which the flow of body fluid is controlled by providing a density gradient difference in the top sheet or the second sheet disposed on the bottom surface of the top sheet.

  For example, in the following Patent Document 2, a water-permeable surface-side sheet facing the body side, a back-side sheet facing the clothing side, and a function of absorbing body fluid contained in the surface-side sheet and the back-side sheet are included. In an absorbent article comprising a liquid-absorbent core, the fiber density on the side facing the liquid-absorbent core is more than the fiber density on the side facing the surface-side sheet between the surface-side sheet and the liquid-absorbent core. An absorbent article provided with a large body fluid permeable sheet (second sheet) has been proposed. In the case of this absorbent article, the body fluid that has passed through the surface side sheet and reached the upper surface of the body fluid permeable sheet moves so as to be guided to the higher fiber density gradient (liquid absorbent core side). It will be absorbed in.

Moreover, in the following patent document 3, in the nonwoven fabric surface sheet processed into the corrugated uneven surface, the fiber density is high at the top and bottom of the wave, and the fiber density is small at the side wall, so that the fiber density is high. And a surface sheet in which a large number of apertures are formed at the boundary between the region where the fiber density is low (see paragraph [0050] of FIG. 4 and FIG. 4).
JP-A-8-302555 JP 2003-210523 A JP 2001-328191 A

  However, in the case of the absorbent article described in Patent Document 2, the diffusibility and absorbability of body fluid are reliably improved by the body fluid-permeable sheet, but the diffusibility on the surface sheet surface that directly contacts the skin is insufficient. The sticky feeling has not been resolved.

  In the surface sheet described in Patent Document 3, the body fluid moves relatively from the low fiber density region side to the high fiber density region side, but the body fluid is retained at the top portion because the top portion of the wave has the high fiber density region. Easy and sticky. In addition, since a large number of apertures are formed at the boundary between the high fiber density region and the low fiber density region, there is a problem that the fiber density gradient cannot be made and menstrual blood is difficult to move to the aperture. .

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an absorbent article having a high cushioning property in the topsheet, which enhances the diffusibility and absorbability of the liquid, effectively prevents the return of bodily fluids and is rich in three-dimensionality. It is in.

As the present invention according to claim 1 to solve the above problems, and liquid-permeable topsheet, Rutotomoni absorber is interposed between the back sheet, a large number of apertures on the lower surface side of the topsheet In the absorbent article in which the formed porous plastic film is disposed ,
The topsheet is made of a nonwoven fabric of heat-fusible fibers, by embossing is applied in a predetermined pattern, porous plastic film while forming a space between the recess and the porous plastic film in contact with the porous plastic film with convex portion raised is adjacent formed alternately from the recess is relatively fiber dense high-density region, the convex portion is a relatively low fiber density and low density regions, the porous plastic The film is set to have a higher hydrophilicity than the top sheet , and the top sheet and the porous plastic film are bonded to each other on the surface of each concave portion of the top sheet facing the porous plastic film. A featured absorbent article is provided.

In the present invention according to the first aspect, the top sheet is made of a non-woven fabric of heat-fusible fibers, and the top sheet is embossed in a predetermined pattern, so that the concave portions in contact with the porous plastic film and the porous Convex portions raised from the porous plastic film are alternately formed adjacent to each other while forming a space with the plastic film, and the concave portions are relatively high-density regions having a high fiber density. In particular, the low density region has a low fiber density. In addition, a porous plastic film having a higher degree of hydrophilicity than the surface sheet and having a large number of apertures is disposed on the lower surface side of the surface sheet.

  Therefore, when the body fluid is discharged to the top sheet, the body fluid present in the convex portion quickly moves toward the concave portion due to the fiber density gradient, so that the diffusibility of the body fluid is improved and the surface side (convex portion) is improved. Since the body fluid is not retained, the sticky feeling is eliminated.

Also, after the body fluid diffuses so as to collect in the recesses, most of it passes through the porous plastic film with high body fluid permeability disposed on the lower layer side and reaches the absorber, and even if pressure is applied thereafter, it will return. Will be prevented.

Furthermore, in the first aspect of the present invention, when the surface sheet and the porous plastic film are separated from each other, the absorbability of the body fluid is lowered, so that the surface sheet and the porous plastic film are bonded to each other in each recess of the surface sheet. Like to do. Therefore, the top sheet and the porous plastic film can be integrated without being spaced apart, and since there is a space between the porous plastic film and the convex portion other than the concave portion serving as the joint portion, it seems to have high cushioning properties. become.

  As the present invention according to claim 2, the top sheet is partitioned into a central region including the body fluid discharge portion and a peripheral region surrounding the central region, and in the central region, the top sheet is integrated with the back side of the top sheet. The absorbent article according to claim 1, further comprising a second nonwoven fabric sheet added thereto, wherein the embossing is applied in a state where the topsheet and the second nonwoven fabric sheet are integrated.

  According to the second aspect of the present invention, since embossing is imparted in the state where the second nonwoven fabric sheet is laminated in the central region, a fiber density difference is easily generated between the convex portion and the concave portion in the central region. For this reason, when the body fluid is discharged to the top sheet, the body fluid present on the convex portion quickly moves toward the concave portion due to a large fiber density gradient.

  As this invention which concerns on Claim 3, the said surface sheet is divided into the center part area | region containing a bodily fluid discharge | emission part, and the peripheral region surrounding this center part area | region, The unevenness | corrugation height difference in the said peripheral area | region is in the said center part area | region. The absorbent article according to claim 1, wherein the absorbent article is set to be larger than the uneven height difference.

  The present invention according to claim 3 emphasizes diffusion and absorption of body fluid due to fiber density difference in the central region, while emphasizing unevenness in the peripheral region with emphasis on wearability such as cushioning and feel. The difference is set to be large.

As the present invention according to claim 4 , in the porous plastic film, the hydrophilicity of the surface on the absorber side is set higher than the surface on the surface sheet side, and a hydrophilicity gradient is provided from the front surface side to the back surface side. An absorbent article according to any one of claims 1 to 3 is provided.

In the present invention described in claim 4, the hydrophilicity of the surface of the porous plastic film on the absorber side is set higher than the surface on the surface sheet side in order to increase the drawing force of the body fluid to the absorber side, A hydrophilicity gradient is given to the side.

As this invention which concerns on Claim 5 , while the said absorber contains a granular superabsorbent resin, the uneven distribution is mixed so that content in the porous plastic film side may become larger than the back sheet side. Item 5. The absorbent article according to any one of Items 1 to 4 .

In the present invention described in claim 5 , since the body fluid reaching the porous plastic film is drawn into the absorbent body, the content of the granular superabsorbent resin on the porous plastic film side is larger than that on the back sheet side. It is unevenly distributed and mixed.

As the present invention according to claim 6, wherein the apertures of the perforated plastic film, opening diameter of the surface sheet side of claim 1-5 or formed in a large funnel than the opening diameter of the absorbent body side An absorbent article is provided.

In the present invention described in claim 6 , the opening is formed in a funnel shape so as not to reverse the body fluid that has once passed through the porous plastic film.

  As described above in detail, according to the present invention, it is possible to increase the diffusibility and absorptivity of the liquid, effectively prevent the body fluid from returning, and have an excellent three-dimensional effect, thereby obtaining an absorbent article having a high cushioning property. .

  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. Between the liquid-permeable surface sheet 3 (hereinafter, simply referred to as a surface sheet), as shown in the figure, the absorber 4 or the absorber 4 preferably surrounded by the crepe paper 5 is interposed, The porous plastic film 6 is disposed between the top sheet 3 and the absorber 4 on the lower surface side of the top sheet 3. In addition, in the circumference | surroundings of the said absorber 4, the said liquid-impermeable back sheet 2 and the surface sheet 3 are joined by adhesion | attachment 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.

  The surface sheet 3 is made of a non-woven fabric of heat-fusible fibers, and is provided with recesses 8, 7... And protrusions 7, 7. , 8... Is a high density region having a relatively high fiber density, and the convex portions 7, 7... Are a low density region having a relatively low fiber density. 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 superabsorbent resin in pulp, or a mixture of chemical fibers in the pulp, What mixed the superabsorbent 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 preferably 10 to 60%. When the content of the superabsorbent resin is less than 10%, 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.

  As shown in FIG. 5, it is desirable that the superabsorbent resin 9 is unevenly distributed and mixed so that the content on the porous plastic film 6 side is larger than that on the back sheet 2 side. Thereby, the body fluid that has reached the porous plastic film 6 can be effectively drawn into the absorber 4.

  The porous plastic film 6 disposed between the liquid-permeable surface sheet 3 and the absorber 4 has a higher hydrophilicity than the surface sheet 3 and a film sheet in which a large number of apertures 6a, 6a. It is. As the material of the film, for example, an olefin-based thermoplastic resin film such as polyethylene or polypropylene is preferably used, but a polyamide-based resin such as polyester or nylon, EVA, or the like can also be used.

The diameter of the opening 6a is 0.05 to 2.0 mm, preferably 0.1 to 1.0 mm, and the number of openings is preferably about 200 to 600 holes / cm ² . In order to form the opening 6a, the synthetic resin sheet is softened 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. The method can be opened by pressurizing air pressure from the top surface of the sheet, or by engraving a large number of slits in the synthetic resin sheet material and then stretching and opening the sheet material, and by piercing many needles (heating needles). There are various methods, such as a method of forming a hole, which can be formed by an appropriate method, but in order to prevent the bodily fluid that has once passed therethrough, as shown in FIG. In addition, it is desirable to form a funnel shape in which the opening diameter d1 on the top sheet 3 side is larger than the opening diameter d2 on the absorber 4 side. FIG. 4A shows an embodiment in which the opening is formed in an inverted truncated cone shape, and FIG. 4B shows an embodiment in which the opening is formed in an irregular shape. Further, in the accompanying drawings, openings other than those in FIG. 4 are omitted.

[Surface layer structure consisting of top sheet 3 and porous plastic film 6]
The surface sheet 3 is made of a non-woven fabric of heat-fusible fibers, and as shown in FIG. 2, the concave portions 8, 8... And the convex portions 7, 7. .. Are alternately formed adjacent to each other in the short-side direction, the recesses 8, 8... Are relatively high density areas, and the protrusions 7, 7... Are relatively low density areas. It is said.

  The material fiber constituting the surface sheet 3 can be, for example, synthetic fibers such as polyethylene or polypropylene, such as olefins, polyesters, polyamides, etc., air-through method, spunlace method, spunbond method, thermal bond method A nonwoven fabric obtained by an appropriate processing method such as 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 drapeability, and the air-through method and the thermal bond method are excellent in terms of being bulky and soft. Among these, it is desirable to use an air-through non-woven fabric that easily gives a fiber density gradient.

  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.

  The top sheet 3 is hydrophilic to body fluid. Specifically, synthetic fibers such as polyethylene or polypropylene, such as olefins, polyesters, and polyamides, are surface-treated with a hydrophilizing agent, or a compound having a hydrophilic group in the synthetic fiber production process, for example, polyethylene glycol is oxidized. Synthetic fibers are swollen or porous by polymerizing in the presence of substances, or by treating with a metal salt such as stannic chloride, partially dissolving the surface to make it porous, and depositing metal hydroxides And using a fiber imparted with hydrophilicity by applying capillary action.

  The concave portions 8, 8,... And the convex portions 7, 7,... Are alternately formed adjacent to the surface sheet 3, and the concave portions 8, 8,. In order to provide embossing so that the convex portions 7, 7... Are in a low density region having a relatively low fiber density, as shown in FIG. 6, the convex portions 10a, 10a... And the concave portions 10b, 10b. Are constituted by a first embossing roll 10 in which a large number of ... are arranged, a second embossing roll 11 in which a large number of convex parts 11a, 11a ... and concave parts 11b, 11b ... are arranged, and in a meshed state. The convex portion 10a of the first embossing roll 10 and the concave portion 11b of the second embossing roll 11 are in contact with or close to each other, and between the first embossing roll 10 and the second embossing roll 11 are used. To the surface sea 3, the concave portions 8, 8... And the convex portions 7, 7... Are alternately formed adjacent to each other, and the fiber density is higher than that of the convex portions 7 by the high compression of the concave portions 8, 8. Can be.

  The interval P between the concave portions 8, 8... Is 2 to 6 mm, preferably 3 to 5 mm, and is formed so that the convex portions 7, 7. Further, it is desirable that the concave portions 8, 8... And the convex portions 7, 7,. Further, the height difference h is desirably 0.3 to 2 mm, preferably 0.5 to 1.0 mm.

  The porous plastic film 6 laminated on the lower surface side of the topsheet 3 is treated with a hydrophilizing agent so that the hydrophilicity is higher than that of the topsheet 3. Such imparting of hydrophilicity is achieved by applying a surfactant (hydrophilizing agent) to the front and back surfaces of the porous plastic film 6.

  Examples of the surfactant include an anionic surfactant, carboxylate, acylated hydrolyzed protein, sulfonate, sulfate ester salt, phosphate ester salt, nonionic surfactant, polyoxyethylene-based interface Activators, carboxylic acid esters, carboxylic acid amides, polyalkylenoxide block copolymers, cationic surfactants, quaternary ammonium salts, amphoteric surfactants, imidazolinium derivatives, etc. Any surfactant may be used as long as it is a known surfactant applied to the fiber.

  Examples of the method for applying the surfactant include spray coating, gravure printing and flexographic printing, and curtain coating using various coaters. The hydrophilicity can be adjusted by adjusting the coating amount of the surfactant.

  Further, in the porous plastic film 6, as shown in FIG. 5, the hydrophilicity of the surface on the absorber 4 side is set higher than the surface on the surface sheet 3 side, and the hydrophilicity gradient is set from the front surface side to the back surface side. You may make it have. By providing the hydrophilicity gradient, the body fluid present on the upper surface of the porous plastic film 6 can be effectively drawn into the absorber 4 side.

  After the topsheet 3 is embossed in a single state, it is laminated with the porous plastic film 6 and preferably joined to each other at the recesses 8 of the topsheet 3. As a joining method, any method such as heat fusion, ultrasonic fusion, and adhesive can be employed. In this case, a space exists between the convex portions 7, 7... Other than the concave portions 8, 8.

Or if the detail the surface structure, as shown in FIG. 3, the convex portions 7, 7 is a relatively low fiber density and low density regions D _L, the recesses 8, 8 ... the relative A high density region _DH having a high fiber density is formed, and a fiber density gradient from the low density region _DL to the high density region _DH is formed. As a result, when the body fluid is discharged to the surface sheet 3, the body fluid present in the convex portions 7, 7... Moves quickly toward the concave portions 8, 8. made with, for body fluid on the surface side (the low-density region D _L side) is eliminated to be water retention, so that feeling sticky is eliminated. In addition, a porous plastic film 6 having high permeability is disposed on the lower layer side, and the porous plastic film 6 is set to have a higher hydrophilicity than the top sheet 3, so that the body fluid is in the recesses 8, 8. After diffusing so as to gather together, most of them permeate the porous plastic film 6 with high water permeability disposed on the lower layer side and reach the absorber 4, and even when pressure is applied thereafter, reversal is prevented. It becomes like this.

  By the way, as shown in FIG. 1, the top sheet 3 is divided into a central region S including the body fluid discharge portion H and a peripheral region surrounding the central region S. 7, the second nonwoven fabric sheet 12 integrally added to the back surface side of the topsheet 3 is provided, and the embossing is applied in a state where the topsheet 3 and the second nonwoven fabric sheet 12 are integrated. You may make it do. The second nonwoven fabric sheet 12 is a nonwoven fabric imparted with hydrophilicity by a hydrophilic treatment, and the hydrophilicity is an intermediate hydrophilicity between the hydrophilicity of the topsheet 3 and the hydrophilicity of the porous plastic film 6. Is desirable.

  When embossing is applied in a state where the second nonwoven fabric sheet 12 is laminated, in the central region S, a difference in fiber density between the convex portions 7, 7... And the concave portions 8, 8. Since the gradient is larger than the surrounding area, the body fluid is moved more rapidly.

Furthermore, as shown in FIG. 8 , the central region S including the body fluid discharge portion H and a peripheral region surrounding the central region S are partitioned, and the uneven height difference in the peripheral region is the central region S. You may make it set larger than the uneven | corrugated height difference in. The body fluid discharge section H places importance on functionality and maintains high body fluid diffusivity and absorbability, while in the surrounding area, by setting a large uneven height difference, such as cushioning and touch feeling Try to improve wearability. The height difference H in the peripheral region is 0.5 to 4 mm, preferably 0.8 to 1.2 mm.

[Other examples]
(1) In the above embodiment, the convex portions 7, 7..., The concave portions 8 are formed in a lattice shape or a zigzag shape in the napkin longitudinal direction and short direction, but the convex portions 7, 7. , 8... May be formed alternately along one direction, that is, in a wave shape.

Part of the absorbent article 1 according to the present invention is a step perspective view. It is the principal part expanded horizontal sectional view. It is a principal part expanded sectional view of the surface sheet 3 for demonstrating an effect. (A) and (B) are the principal part expanded sectional views which show the opening aspect of the porous plastic film 6, both. It is a principal part expanded sectional view which shows the modification of this absorbent article. It is a figure which shows the meshing state of the 1st embossing roll 10 and the 2nd embossing roll 11. FIG. It is a cross-sectional view showing a modification of the top sheet. It is a cross-sectional view showing another modification of the surface sheet 3.

DESCRIPTION OF SYMBOLS 1 ... Absorbent article (sanitary napkin), 2 ... Liquid-impermeable back sheet, 3 ... Liquid-permeable surface sheet, 4 ... Absorber, 5 ... Crepe paper, 6 ... Porous plastic film, 7 ... Convex part, DESCRIPTION OF SYMBOLS 8 ... Concave part, 9 ... High water absorption resin, 10 ... 1st embossing roll, 10a ... Convex part, 10b ... Concave part, 11 ... 2nd embossing roll, 11a ... Convex part, 11b ... Concave part, 12 ... 1st 2 non-woven fabric sheet, D _L ... low density area, D _H ... high density area, S ... central area

Claims (6)

Liquid-pervious topsheet, in absorbent articles where the absorber is interposed Rutotomoni, porous plastic film which many apertures are formed on the lower surface side of the topsheet is disposed between the backsheet,
The topsheet is made of a nonwoven fabric of heat-fusible fibers, by embossing is applied in a predetermined pattern, porous plastic film while forming a space between the recess and the porous plastic film in contact with the porous plastic film with convex portion raised is adjacent formed alternately from the recess is relatively fiber dense high-density region, the convex portion is a relatively low fiber density and low density regions, the porous plastic The film is set to have a higher hydrophilicity than the top sheet , and the top sheet and the porous plastic film are bonded to each other on the surface of each concave portion of the top sheet facing the porous plastic film. Absorbent article characterized.   The top sheet is divided into a central region including a body fluid discharge portion and a peripheral region surrounding the central region, and the second nonwoven fabric sheet is integrally added to the back side of the top sheet in the central region. The absorbent article according to claim 1, wherein the embossing is applied in a state where the top sheet and the second nonwoven fabric sheet are integrated.   The surface sheet is partitioned into a central region including a body fluid discharge portion and a peripheral region surrounding the central region, and the uneven height difference in the peripheral region is set larger than the uneven height difference in the central region. The absorbent article according to claim 1. Wherein the porous plastic film, the hydrophilicity of the surface of the absorbent body side is set higher than the surface of the surface sheet side, according to claim 1 to 3 or which toward the back surface side are so as to have a hydrophilicity gradient from the surface side Absorbent articles. The absorber is configured to contain a superabsorbent polymer particulate of claim 1-4 or that are mixed unevenly so much the content of the porous plastic film side of the back sheet side Absorbent article. The absorbent article according to any one of claims 1 to 5, wherein the opening of the porous plastic film is formed in a funnel shape in which the opening diameter on the top sheet side is larger than the opening diameter on the absorber side.

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