JP2021171484A - Absorbent article - Google Patents

Abstract

To provide an absorbent article which is provided with a high absorbent sheet, has good wearing comfort and fit feeling, and has excellent diffusibility of body fluid and absorption rate.SOLUTION: An absorbent article 50 includes: a liquid-permeable top sheet 25; a liquid-impermeable back sheet 30; and an absorber 1 arranged between the top sheet 25 and the back sheet 30. The absorber 1 is provided with a high absorbent sheet 10 that includes: a substrate nonwoven fabric 11 which has a raised surface 11a and a non-raised surface 11b and in which the non-raised surface 11b is arranged so that it faces the top sheet 25; a high absorbent polymer 12 fixed and supported between napped fibers 11x on the raised surface 11a of the substrate nonwoven fabric 11; and a hydrophilic sheet 20 covering the raised surface 11a of the substrate nonwoven fabric 11. The hydrophilic sheet 20 includes a pulp containing nonwoven fabric whose flexural rigidity is 0.02 gf.cm2/cm or more and whose wet strength is 10 N/50 mm or more.SELECTED DRAWING: Figure 4

Description

The present invention relates to absorbent articles.

The absorbent article generally includes a liquid-permeable top sheet, a liquid-impermeable back sheet, and an absorber arranged between them, and absorbs body fluid such as urine that has permeated the top sheet. Absorbed and retained by the body. There are various types of absorbent articles, regardless of whether they are for adults or infants, depending on the application, such as tape-type disposable diapers, pants-type disposable diapers, urine absorbing pads, and light incontinence pads.

Conventionally, as an absorber, it is common to use fluff pulp and a super absorbent polymer (hereinafter, also referred to as “SAP”) in combination. However, for the purpose of further improving the wearing feeling, appearance, touch, etc. of the absorbent article and further reducing the reversion of body fluids such as urine, the two non-woven fabrics were fixed with a hot melt adhesive between them. Various absorbent articles using SAP particles and a highly absorbent sheet containing (hereinafter, also referred to as "SAP sheet") as an absorber have been proposed.

For example, in Patent Document 1, one surface is arranged in a stripe shape extending in the longitudinal direction between the first and second nonwoven fabrics, each of which is an adhesive-coated surface, and the adhesive-coated surfaces of the first and second nonwoven fabrics. The adhesive is intermittently applied in the region facing the SAP layer on the adhesive-coated surface of the second non-woven fabric, and the adhesive is intermittently applied on both sides in the width direction of the SAP layer without interposing the SAP layer. A highly absorbent sheet in which an adhesive is continuously applied in the longitudinal direction is disclosed on each of the adhesive-coated surfaces of the first and second nonwoven fabrics that are directly opposed to each other.

In Patent Document 2, the absorber disposed between the top sheet and the back sheet includes first and second absorbers containing two non-woven fabrics and SAP particles arranged between them, respectively. The first and second absorbers arranged on one and the other in the width direction have first and second folds extending in the longitudinal direction, respectively, and the first and second folds face each other to form a highly absorbent sheet. It is disclosed. Further, Patent Document 2 further includes a third absorber containing two non-woven fabrics and SAP particles arranged between them, and the third absorber is arranged above the first and second absorbers. Sexual articles are disclosed.

Japanese Unexamined Patent Publication No. 2006-158676 Japanese Unexamined Patent Publication No. 2013-42882 (Claim 1, Claim 5)

Since the SAP sheet used in Patent Documents 1 and 2 and many other absorbent articles has poor compressibility in the thickness direction, the wearer can feel the rugged and hard feel of the cured product of SAP particles and hot melt adhesive on the skin. It is easy to feel, the feeling of wearing and fitting is greatly reduced, and the feeling of discomfort when wearing is increased. Further, in many SAP sheets, by fixing SAP particles to a non-woven fabric with a hot melt adhesive, SAP particles are present at a high density on the surface thereof, and as a result, a space for the SAP particles to absorb body fluid and expand. Is reduced. Therefore, the conventional SAP sheet is not sufficiently satisfactory in terms of diffusivity of body fluid, absorption rate, and absorption.

Further, the conventional SAP sheet is made of SAP and a non-woven fabric in order to reduce the thickness, and does not contain fluff pulp, so that there is a problem that the wet back immediately after water absorption is poor. Also, if a paper sheet is used instead of the non-woven fabric, the tensile strength when wet is low, so the SAP sheet may be torn by body pressure after water absorption, causing the SAP to leak to the outside of the absorbent article. I have a problem.

An object of the present invention is to provide an absorbent article having a highly absorbent sheet, having a good wearing feeling and a good fit, and having excellent diffusivity of body fluid and absorption rate.

As a result of intensive research to solve the above problems, the present inventor has obtained a base non-woven fabric having a raised surface and capable of supporting a highly absorbent polymer between the raised fibers on the raised surface, a highly absorbent polymer, and the like. By using a pulp-containing non-woven fabric as a hydrophilic sheet having a predetermined bending stiffness and wet strength in combination with a predetermined structure, a highly absorbent sheet as an absorber is formed, and this highly absorbent sheet is used. As a result, it has been found that an absorbent article satisfying the purpose can be obtained, and the present invention has been completed. The present invention relates to the following absorbent articles.

(1) An absorbent article comprising a liquid-permeable top sheet, a liquid-impermeable back sheet, and an absorber arranged between the top sheet and the back sheet.
The absorber is
A base non-woven fabric having a brushed surface and a non-raised surface and arranged so that the non-raised surface faces the top sheet.
A highly absorbent polymer fixedly supported between the raised fibers on the raised surface of the base non-woven fabric,
A hydrophilic sheet covering the raised surface of the base non-woven fabric and
Equipped with a highly absorbent sheet, including
The hydrophilic sheet is
An absorbent article containing a pulp-containing non-woven fabric having a bending stiffness of 0.02 gf · cm ² / cm or more and a wet strength of 10 N / 50 mm or more.
(2) The hydrophilic sheet has both end faces in the width direction facing each other between the top sheet and the base non-woven fabric, and covers both end faces in the width direction of the base non-woven fabric together with the raised surface of the base non-woven fabric. The absorbent article of (1) above, which has a three-dimensional shape folded in three.
(3) The hydrophilic sheet is stretched in the width direction so that both ends in the width direction cover the non-raised surface of the substrate nonwoven fabric and overlap each other, and the overlapping width dimension is 5 of the width dimension of the absorber. % Or more and 50% or less, the absorbent article of the above (1).
(4) The absorbent article according to any one of (1) to (3) above, wherein the pulp-containing nonwoven fabric has a basis weight of 30 g / m ² or more and 80 g / m ^{2 or less.}
(5) The substrate nonwoven fabric is an air-through nonwoven fabric, the basis weight of the air-through nonwoven fabric is 20 g / m ² or more and 80 g / m ² or less, and the thickness of the fibers constituting the air-through nonwoven fabric is 1.6 dtex or more and 14 dtex or more. The absorbent article according to any one of (1) to (4) above.
(6) The absorbent article according to any one of (1) to (5) above, wherein the basis weight of the highly absorbent polymer in the highly absorbent sheet is 150 g / m ² or more and 800 g / m ^{2 or less.}

According to the present invention, it is possible to provide an absorbent article having a highly absorbent sheet, having a good wearing feeling and a good fit, and having excellent diffusivity of body fluid and absorption rate.

It is a top view which shows typically the structure of the absorbent article which concerns on 1st Embodiment of this invention. It is a perspective view which shows typically the structure of the substrate nonwoven fabric provided in the absorbent article shown in FIG. It is a side view which shows typically the structure in which the highly absorbent polymer is fixedly supported on the substrate nonwoven fabric provided in the absorbent article shown in FIG. It is sectional drawing which shows typically the structure of the absorber provided in the absorbent article shown in FIG. It is sectional drawing which shows typically the structure of the absorber which concerns on another embodiment.

In the present specification, the wearing of the absorbent article means a state in which the absorbent article is worn on the body before and after the absorption of the body fluid. In the absorbent article, the longitudinal direction is the direction indicated by Y in the figure, which extends to the front and back of the body through the wearer's crotch when the absorbent article is worn on the body, and the width direction is the longitudinal direction. The direction indicated by X in the figure is orthogonal to each other, and the thickness direction is the direction indicated by Z in the drawing in which the constituent members are laminated. The skin side surface is the surface that comes into contact with the wearer's skin and the surface that faces the skin when the absorbent article is worn, and the non-skin side surface is the surface that comes into contact with the wearer's clothes or the surface that faces the clothes. .. Body fluid refers to the liquid excreted from the body such as urine, blood, and water in loose stool.

<Absorbable article>
Hereinafter, the absorbent article of the present embodiment will be described in detail with reference to the drawings. FIG. 1 shows an absorbent article 50 according to the first embodiment. FIG. 2 shows the substrate nonwoven fabric 11 in the absorbent article 50. FIG. 3 shows the substrate nonwoven fabric 11 on which the highly absorbent polymer 12 is fixedly supported in the absorbent article 50. FIG. 4 shows the absorber 1 in the absorbent article 50. FIG. 5 shows the absorber 2. These drawings do not specify the shape, dimensions, size relationship, etc. of each component in the absorbent article 50.

The absorbent article 50 of the present embodiment can be used as various absorbent articles regardless of whether it is for babies or adults, but typically, a light incontinence pad, a urine absorbing pad, a pants-type disposable diaper, a tape-stopping disposable diaper, etc. Can be mentioned. Various paper diapers as an outer and an absorbent article 50 as an inner may be combined. The dimensions of the absorbent article 50 in the longitudinal direction and the dimensions in the width direction are not particularly limited, but are, for example, a range of 100 mm or more and 800 mm or less, and a range of 50 mm or more and 500 mm or less. By adjusting the dimensions of the absorbent article 50 to the above range, absorbent articles of various uses can be obtained.

As shown in FIG. 1, the absorbent article 50 is arranged so as to face the liquid-permeable top sheet 25 and the top sheet 25, which are located relatively on the skin side when worn, and are worn. The liquid-impermeable back sheet 30 located relatively on the non-skin side, the absorber 1 arranged between the top sheet 25 and the back sheet 30, and the skin-side surface of the top sheet 25 are provided. It is provided with a pair of three-dimensional gathers 40. The absorber 1 has a structure sandwiched between the top sheet 25 and the back sheet 30, and body fluid such as urine is absorbed and held by the absorber 1 through the top sheet 25. Leg gathers, waist gathers, side flaps and the like can be appropriately provided depending on the use and type of the absorbent article 50.

In the absorbent article 50, since the absorber 1 does not contain fluff pulp, the absorption performance is good, and the absorption rate is unlikely to decrease due to gel blocking or the like even after repeated body fluid absorption, the absorbent body 1 has a smooth and comfortable feel. The feeling of wearing and fitting is good, there is no discomfort during wearing, there is no discomfort during wearing, and the body fluid is quickly absorbed, and the diffusivity and absorption speed of the body fluid are excellent. Further, the absorbent article 50 is an absorber 1 in which a substrate nonwoven fabric 11 in which a highly absorbent polymer 12 is fixedly supported on a raised surface 11a and a pulp-containing nonwoven fabric as a hydrophilic sheet 20 are used in combination in a predetermined structure. The provision has an advantage that not only the liquid return in the state of holding the body fluid but also the liquid return is remarkably suppressed even in the state where the body fluid is not sufficiently retained immediately after the wearer discharges the body fluid. There is.

Hereinafter, each of the sheet-shaped or plate-shaped constituent members will be described in more detail in the order of the top sheet 25, the absorber 1, the back sheet 30, and the three-dimensional gather 40. In addition, these constituent members may have a three-dimensional structure other than a sheet shape and a plate shape.

(Top sheet)
The top sheet 25 is a liquid-permeable sheet-like member that allows body fluids to quickly pass toward the absorber 1, and is arranged so as to face the back sheet 30 with the absorber 1 interposed therebetween. Since the top sheet 25 may come into contact with the wearer's skin, a base material having a soft feel and a property of not irritating the skin is preferable. Examples of the base material include a hydrophilic non-woven fabric, a composite non-woven fabric which is a product of the same or different types of hydrophilic non-woven fabric, an open film such as an open polyethylene film, and a foam film such as urethane foam. The hydrophilic non-woven fabric uses, for example, synthetic fibers made of synthetic resin such as polypropylene or polyethylene, recycled fibers such as rayon, and natural fibers such as cotton, and is subjected to an air-through method, a thermal bond method, a spunlace method, a spunbond method, etc. It is obtained by processing by a known method.

Further, the surface of the top sheet 25 may be embossed or perforated in order to improve the liquid permeability. As a method for performing these embossing and drilling processes, known methods can be carried out without limitation. Further, in order to reduce irritation to the skin, the top sheet 25 may contain a lotion, an antioxidant, an anti-inflammatory component, a pH adjuster, an antibacterial agent, a moisturizer and the like.

From the viewpoint of strength, workability and liquid return amount, the basis weight of the top sheet 25 ^{is preferably 15 g / m 2} or more and 40 g / m ² or less. The shape of the top sheet 25 is not particularly limited, and may be any shape that covers the absorber 1 that is required to guide the body fluid to the absorber 1 so as not to leak.

(Absorber)
As shown in FIGS. 2 to 4, the absorber 1 of the present embodiment has a high absorption using a substrate nonwoven fabric 11 carrying the highly absorbent polymer 12 and a hydrophilic sheet 20 in combination in a predetermined three-dimensional structure. A sex sheet (hereinafter, also referred to as “SAP sheet”) 10 is provided. The substrate nonwoven fabric 11 has a raised surface 11a on one surface and a non-raised surface 11b on the other surface, and the highly absorbent polymer 12 is fixedly supported between the raised fibers 11x on the raised surface 11a of the substrate nonwoven fabric 11. In the highly absorbent sheet 10, the substrate nonwoven fabric 11 is arranged so that the non-raised surface 11b faces the top sheet 25. The hydrophilic sheet 20 contains a pulp-containing non-woven fabric having a bending stiffness of 0.02 gf · cm ² / cm or more and a wet strength of 10 N / 50 mm or more, and covers the raised surface 11a of the base non-woven fabric 11. Here, the bending stiffness and the wet strength (tensile strength when wet) are values measured by the method described later. The entire surface or a part of the surface of the absorber 1 may be embossed or the like.

The hydrophilic sheet 20 has a flat sheet-like three-dimensional shape that covers the raised surface 11a of the base nonwoven fabric 11 (first embodiment of the hydrophilic sheet 20), and is preferably in the width direction together with the raised surface 11a of the substrate nonwoven fabric 11. It has a three-dimensional shape folded in three so as to cover both end faces 11A and 11B (second embodiment of the hydrophilic sheet 20), and more preferably, both end faces 20a and 20b in the width direction are formed as shown in FIG. The top sheet 25 and the substrate non-woven fabric 11 face each other and cover the periphery of both ends of the non-brushed surface 11b of the substrate non-woven fabric 11 in the width direction, and also cover the raised surfaces 11a of the substrate non-woven fabric 11 and both end surfaces 11A and 11B in the width direction. As described above, it has a three-dimensional shape folded in three (the third embodiment of the hydrophilic sheet 20). Further, in the third embodiment of the hydrophilic sheet 20, as shown in FIG. 5, both end faces 20a and 20b in the width direction of the hydrophilic sheet 20 may overlap between the top sheet 25 and the substrate non-woven fabric 11. Fourth embodiment of the hydrophilic sheet 20).

The absorber 1 of the present embodiment has dimensions in the longitudinal direction, for example, in the range of 100 mm or more and 800 mm or less, or in the range of 150 mm or more and 500 mm or less. Further, the dimension D in the width direction of the absorber 1 is, for example, a range of 50 mm or more and 500 mm or less, or a range of 60 mm or more and 400 mm or less.

In the present embodiment, as described above, the hydrophilic sheet 20 covers the raised surface 11a of the base non-woven fabric 11, preferably the raised surface 11a of the base non-woven fabric 11, and the widthwise both end surfaces 11A and 11B of the base non-woven fabric 11. More preferably, it covers the raised surfaces 11a of the base nonwoven fabric 11, the widthwise both end faces 11A and 11B of the substrate nonwoven fabric 11, and the widthwise both ends of the non-woven surface 11b of the substrate nonwoven fabric 11 and the peripheral region extending in the longitudinal direction. According to the present embodiment, the base non-woven fabric 11 in which the highly absorbent polymer 12 is fixedly supported on the raised surface 11a and the hydrophilic non-woven fabric 20 have a bending stiffness (flexural rigidity) of 0.02 gf · cm ² / cm or more. Alternatively, a pulp-containing non-woven fabric having a wet strength in the range of 0.02 gf · cm ² / cm or more and 0.6 gf · cm ² / cm or less and a wet strength in the range of 10 N / 50 mm or more or 10 N / 50 mm or more and 70 N / 50 mm or less. By using in combination with and in a predetermined three-dimensional structure, the absorber 1 is not too soft, has appropriate flexibility and rigidity while maintaining thinness, and not only improves wearing feeling and fit. The strength of the absorber 1 after absorbing the body fluid is increased, and when the absorbent article 50 is removed from the body when worn or after absorbing the body fluid, the absorber 1 is not torn or damaged and can be removed cleanly. Further, as described above, the absorber 1 has an appropriate rigidity, and even if the operating speed is increased at the time of production, tearing or the like is extremely unlikely to occur, so that the production efficiency and the yield can be improved.

Further, according to the present embodiment, when the high-absorbency polymer 12 is fixedly supported between the raised fibers 11x of the raised surface 11a of the base nonwoven fabric 11 in the high-absorbency sheet 10, the high-yielding polymer 12 is raised with the raised surface 11a. Since it is supported by the fibers 11x, the amount of the hot melt adhesive used can be reduced, the densification of the highly absorbent polymer 12 is suppressed, and the polymer 12 causes the body fluid to surround the highly absorbent polymer 12. It can absorb and form an expandable space. In addition, gel blocking in which highly absorbent polymers 12 that have absorbed and swollen body fluids are bound to each other is extremely unlikely to occur. As a result, the diffusivity of the body fluid as a whole of the absorber 1 and the absorption rate of the body fluid are increased, and the stiff feeling derived from the hot melt adhesive is less likely to occur. Further, since the raised surface 11a of the substrate nonwoven fabric 11 which is a constituent member of the absorber 1 is covered with the pulp-containing material as the hydrophilic sheet 20, the body fluid is uniformly distributed throughout the absorber 1 and spreads over the entire absorber 1. The distributed highly absorbent polymer 12 can be used evenly to efficiently absorb body fluids. Therefore, the absorbent article 50 including the absorber 1 has high diffusivity and absorption rate of body fluid, is excellent in body fluid absorption, and has a good wearing feeling.

Further, according to the present embodiment, the absorber 1 is configured such that the non-raised surface 11b of the substrate nonwoven fabric 11 faces the top sheet 25. Further, as in the absorber 2 shown in FIG. 5, the non-raised surface 11b of the substrate non-woven fabric 11 is configured so that both ends 20a and 20b in the width direction of the hydrophilic sheet 20 are stretched and overlapped to close the body fluid. The diffusivity and absorption rate of the hydrophilic sheet 20 are further significantly improved (the fourth embodiment of the hydrophilic sheet 20).
Hereinafter, the absorber 1 and each component thereof will be described.

(Base non-woven fabric)
As shown in FIG. 2, the one-sided surface 11a of the base non-woven fabric 11 is in a state in which the fibers 11x constituting the base non-woven fabric 11 are raised. Therefore, in addition to the original bulkiness of the non-woven fabric, by imparting an appropriate thickness and softness to the highly absorbent sheet 10, an appropriate cushioning property can be generated and a fit feeling at the time of wearing can be improved. Further, by raising the base nonwoven fabric 11 as described above, the highly absorbent polymer 12 can be dispersed and fixedly supported between the raised fibers 11x of the substrate nonwoven fabric 11. Examples of the method of raising the surface 11a on one side of the substrate nonwoven fabric 11 include a method of fluffing with a rotary saw blade, a method of fluffing with a needle punch, and the like, and a method of raising fluff with a rotary saw blade from the viewpoint of in-line productivity and cost. Is preferably used.

The raised state in the present embodiment is not particularly limited, and it is sufficient if the raised state can be visually confirmed. More specifically, the raised rate of the substrate nonwoven fabric 11 is preferably 5% or more and 90% or less, and 8% or more and 80%. More preferably, it is less than%. The brushing rate means the rate of increase in the thickness of the substrate nonwoven fabric 11 due to the brushing process. For example, when the thickness of the base non-woven fabric 11 before raising is T1 and the thickness of the base non-woven fabric 11 after raising is T2, the raising rate (%) is represented by [(T2-T1) / T1] × 100. Can be done. The above thickness is obtained by measuring the thickness under no load using a height gauge (manufactured by Mitutoyo Co., Ltd.). The other surface 11b of the substrate nonwoven fabric 11 is a non-raised surface in the present embodiment, but the present invention is not limited to this, and fibers may be raised.

Examples of the substrate non-woven fabric 11 include non-woven fabrics such as air-through non-woven fabric, point-bonded non-woven fabric, spunbond non-woven fabric, and melt-blow non-woven fabric, and composite non-woven fabric in which spunbond non-woven fabric / melt-blow non-woven fabric, spunbond non-woven fabric / melt-blow non-woven fabric / spunbond non-woven fabric are laminated. Can be mentioned. Among these non-woven fabrics, air-through non-woven fabrics are preferable from the viewpoint of increasing the bulk.

The thickness of the base non-woven fabric 11 is not particularly limited, but from the viewpoint of the balance between wearing feeling and absorption performance, a range of 0.3 mm or more and 11.0 mm or less, a range of 0.5 mm or more and 5.0 mm or less, or 0.5 mm or more 2 The range is 0.0 mm or less. The basis weight of the substrate nonwoven fabric 11 is not particularly limited, but is, for example, 20 g / m ² or more and 200 g / m ² or less, 20 g / m ² or more and 160 g / m ² or less, or 20 g / m ² or more and 80 g / m. The range is m ^{2 or less.}

When an air-through non-woven fabric is used as the substrate non-woven fabric 11, the basis weight ^{of the air-through non-woven fabric is in the range of 20 g / m 2} or more and 80 g / m ² or less, and the thickness of the fibers constituting the air-through non-woven fabric is in the range of 1.6 dtex or more and 14 dtex or less. The range is 1.8 dtex or more and 9.0 dtex or less, or 2.0 dtex or more and 6.0 dtex or less. By adjusting the thickness of the fibers constituting the air-through non-woven fabric within the above range, the highly absorbent polymer 12 can be easily dispersed and fixedly supported between the raised fibers 11x of the air-through non-woven fabric, and the highly absorbent polymer on the raised surface 11a can be easily fixed and supported. The uniform dispersibility of 12 is improved.

(Highly absorbent sheet)
As shown in FIGS. 2 to 4, the highly absorbent sheet 10 used for the absorber 1 of the present embodiment is fixed between the base non-woven fabric 11 having a raised surface 11a on one side and the fibers 11x of the raised portion of the base non-woven fabric 11. It has a supported highly absorbent polymer 12 and a hydrophilic sheet 20 having a predetermined inner tri-fold structure. The highly absorbent polymer 12 is dispersed and fixedly supported between the fibers 11x of the raised portion of the substrate nonwoven fabric 11, and the body fluid such as urine is appropriately diffused or held in the substrate nonwoven fabric 11 around the highly absorbent polymer 12. , Absorption performance is improved, and sufficient absorption performance can be ensured even if it does not contain fluff pulp.

(Highly absorbent polymer)
The highly absorbent polymer 12 is not particularly limited as long as it can absorb urine and prevent backflow, and is composed of polyacrylate, polyasparaginate, (starch / acrylic acid) graft copolymer, ( Examples thereof include a copolymer (acrylic acid / vinyl alcohol), a copolymer (isobutylene / maleic anhydride), and a saponified product thereof. Among these, polyacrylate is preferable, and sodium polyacrylate is more preferable, from the viewpoint of the amount of absorption per weight. The basis weight of the highly absorbent polymer 12 in the highly absorbent sheet 10 is, for example, in the range of ^{150 g / m 2} or more and 800 g / m ^{2 or less.} Is preferable.

Further, by avoiding the use of the fine powder highly absorbent polymer 12 having poor fluidity as a powder, the basic performance regarding absorption is improved, and the rugged tactile sensation generated by the hardening of the high absorbent sheet 10 is achieved. From the viewpoint of reducing the amount of particles, it is preferable to use the highly absorbent polymer 12 in the form of particles having a medium particle size as the highly absorbent polymer 12. The medium particle size is, for example, in the range of 50 μm or more and 600 μm or less, or 100 μm or more and 500 μm or less.

The highly absorbent polymer 12 is preferably fixedly supported between the fibers 11x of the raised portion of the base nonwoven fabric 11 by a hot melt adhesive, and has high absorbency when the basis weight of the substrate nonwoven fabric 11 is relatively low. Hot melt adhesives work particularly well to reinforce the fixation and support of the polymer 12. The content of the hot melt adhesive is, for example, in the range of ^{10 g / m 2} or less from the viewpoint of not inhibiting the absorbency of the highly absorbent polymer 12 and not impairing the touch when worn. As the hot melt adhesive, one having a melting point of 100 ° C. or higher and 180 ° C. or lower can be used without particular limitation. Examples thereof include melt adhesives and olefin-based hot melt adhesives such as ethylene-vinyl acetate copolymers. As a method for applying the hot melt adhesive, known methods such as a curtain coating method in which the hot melt adhesive in a molten state is applied from a nozzle in a non-contact manner, a spiral method, and a slot method in which the hot melt adhesive is applied by a contact method can be used.

(Hydrophilic sheet)
The highly absorbent sheet 10 of the present embodiment prevents the highly absorbent polymer 12 from leaking to the outside of the highly absorbent sheet 10 by adhering the raised surface 11a of the substrate nonwoven fabric 11 and the hydrophilic sheet 20. It can also improve the feel when worn. The hydrophilic sheet 20, as described above, the bending stiffness (flexural rigidity) of 0.02gf · ^cm 2 / ^cm or more ranges or 0.02gf · ^cm 2 / ^cm or more 0.6gf · ^cm 2 / ^cm or less of A pulp-containing non-woven fabric having a range of 10 N / 50 mm or more or a wet strength of 70 N / 50 mm or less on 10 N / 50 mm is used. When the raised surface 11a of the substrate nonwoven fabric 11 is adhered to the hydrophilic sheet 20, it is preferable to fix the substrate nonwoven fabric 11 and the hydrophilic sheet 20 by hot melt adhesive or heat embossing.

If the bending stiffness of the hydrophilic sheet 20 is ^{less than 0.02 gf · cm 2} / cm and / or the wet strength is less than 10 N / 50 mm, the rigidity of the absorber 1 is reduced, and the body is repeatedly absorbed with body fluid or after the body fluid is absorbed. When it is removed from the absorber 1, the absorber 1 tends to be torn or the like. If the bending stiffness of the hydrophilic sheet 20 ^{exceeds 0.6 gf · cm 2} / cm and / or the wet strength exceeds 70 N / 50 mm, the absorber 1 becomes too hard, and the wearability and fit of the absorbent article 50 become too hard. The feeling tends to decrease and the feeling of discomfort when worn tends to increase. Bending stiffness and wet strength can be measured by the method described later.

(Pulp-containing non-woven fabric)
The pulp-containing nonwoven fabric used as the hydrophilic sheet 20 includes a nonwoven fabric and a pulp fiber web laminated on at least one surface of the nonwoven fabric (first embodiment of the pulp-containing nonwoven fabric). In the present embodiment, for example, the pulp fiber web that contributes to body fluid diffusivity in the absorber 1 faces the raised surface 11a of the base non-woven fabric 11, and the non-woven fabric that contributes to imparting strength to the absorber 1, for example, faces the outside. It is preferable that the pulp-containing non-woven fabric is arranged so as to face it.

A preferred pulp-containing non-woven fabric comprises a non-woven fabric and a pulp fiber web integrated on at least one surface of the non-woven fabric (second embodiment of the pulp-containing non-woven fabric). Here, "integration" means that at least before and after the use of the absorbent article 50, the non-woven fabric and the pulp fiber web are not partially peeled off and their functions are not significantly reduced. The basis weight of the non-woven fabric is, for example, 7 g / m ² or more and 30 g / m ² or less, and the basis weight of the pulp fiber web is, for example, 30 g / m ² or more and 50 g / m ² or less. By setting each basis weight of the non-woven fabric and the pulp fiber web within the above range, it becomes easy to adjust the basis weight of the pulp-containing non-woven fabric to an appropriate range described later.

Among the pulp-containing non-woven fabrics, an integrated product by water flow confounding is preferable (the third embodiment of the pulp-containing non-woven fabric). The integrated product is, for example, a pulp-containing non-woven fabric in which wood pulp fibers are entangled with a water jet on the surface of the non-woven fabric without using a binder, and the pulp fiber web is provided integrally. In such a pulp-containing non-woven fabric, the fibers constituting the non-woven fabric and the wood pulp fibers are entangled on one surface of the non-woven fabric to integrate the pulp fiber web, and a part of the wood pulp fibers penetrates the non-woven fabric in the thickness direction. The non-woven fabric and the pulp fiber web are extremely tightly bonded to each other so as to be exposed on the other surface (the fourth embodiment of the pulp-containing non-woven fabric).

The wood pulp fiber used here is not particularly limited, and examples thereof include softwood bleached kraft pulp (hereinafter, also referred to as “NBKP”) such as radiata pine, slash pine, southern pine, lodge pole pine, spruce and douglas fur. Be done. NBKP can be used alone or in combination of two or more. The non-woven fabric laminated on the pulp fiber web is not particularly limited, but a spunbonded non-woven fabric composed of synthetic resin fibers is preferable from the viewpoint of the strength and liquid permeability of the entire pulp-containing non-woven fabric, and polypropylene as the synthetic resin fiber. A spunbonded non-woven fabric containing fibers is more preferable, and a spunbonded non-woven fabric made of polypropylene fibers is further preferable.

In the pulp-containing non-woven fabric, the weight ratio between the non-woven fabric and the pulp fiber web (nonwoven fabric / pulp fiber web) is, for example, in the range of 40/60% by weight or more and 10/90% by weight or less. When the content of the pulp fiber web is less than 60% by mass, the pulp-containing nonwoven fabric tends to be poor in texture and absorption of sweat and tends to be stuffy, and when it exceeds 90% by mass, the pulp-containing nonwoven fabric tends to be hard. The non-woven fabric integrated with the pulp fiber web is not particularly limited, but a spunbonded non-woven fabric is preferable from the viewpoint of supportability to the pulp fiber web, strength and softness of the entire pulp-containing non-woven fabric, texture, and the like, and polypropylene fiber. The spunbonded non-woven fabric containing the above is more preferable, and the spunbonded non-woven fabric made of polypropylene fiber is further preferable.

The basis weight of the pulp-containing nonwoven, from the viewpoint of the thickness and strength of products, for example, in the range of 30 g / ^{m 2} or more 80 g / ^{m 2} or less or in the range of 40 g / ^{m 2} or more 60 g / ^{m 2.} If it is less than 30 g / m ² , the pulp-containing non-woven fabric becomes too soft and the production yield tends to decrease, and it tends to be easily torn after absorption of body fluid. If it ^{exceeds 80 g / m 2} , the pulp-containing non-woven fabric increases in hardness and thickness. , The absorber 1 tends to become hard and impair the comfort when worn.

The bending stiffness and wet strength of the pulp-containing non-woven fabric can be adjusted to desired values by appropriately selecting, for example, the material, thickness, basis weight, weight ratio and the like of the pulp fiber web and the non-woven fabric.

<Manufacturing method of absorber>
The method for producing the absorber 1 is not particularly limited, and examples thereof include the following methods. The surface of one side of the substrate nonwoven fabric 11 is raised using a rotary saw blade or a needle punch.
Then, the highly absorbent polymer 12 is fixedly supported between the fibers 11x of the raised portion of the substrate nonwoven fabric 11 with a hot melt adhesive or the like. Then, the raised surface 11a side of the substrate nonwoven fabric 11 and the hydrophilic sheet 20 are adhered with a hot melt adhesive or the like to obtain a highly absorbent sheet 10. This highly absorbent sheet 10 is used as the absorber 1.

In this embodiment, a transfer sheet (not shown) may be provided. The transfer is placed, for example, between the topsheet 25 and the absorber 1. The transfer sheet is not particularly limited as long as it is a liquid-permeable base material. Examples thereof include a composite non-woven fabric in which non-woven fabrics are laminated, a foamed film made of urethane foam, polyethylene foam and the like, and a composite sheet which is a laminate of two or more of these. Among these, an air-through non-woven fabric is preferable from the viewpoint of preventing the transfer of body fluid to the three-dimensional gather 40. The basis weight of the transfer sheet is in the range of for example 20 g / ^{m 2} or more ranges or 20 g / ^{m 2} or more 60 g / ^{m 2} or less.

(Back sheet)
The back sheet 30 may be formed by using a base material having a liquid impermeable property so that the body fluid held by the absorber 1 does not wet the clothes, and the resin film or the resin film and the non-woven fabric are laminated. It is formed from a material such as a composite sheet. The non-woven fabric used for the composite sheet is not particularly limited in the manufacturing method, and for example, spunbonded non-woven fabric, melt-blow non-woven fabric, composite non-woven fabric which is a laminate of spunbond non-woven fabric / melt-blow non-woven fabric, spunbond non-woven fabric / melt-blow non-woven fabric / spunbond non-woven fabric. Examples thereof include a composite non-woven fabric which is a laminated body and a composite material thereof. Examples of the resin film include polyester, polyvinyl alcohol, polyethylene, polypropylene, and a composite film of polyethylene and polypropylene.

From the viewpoint of strength and workability, the basis weight of the back sheet 30 ^{is preferably 15 g / m 2} or more and 40 g / m ² or less. Further, in order to prevent stuffiness at the time of mounting, it is preferable that the back sheet 30 has air permeability. In order to provide the back sheet 30 with breathability, for example, a filler may be blended in the resin film of the base material, or the back sheet 30 may be embossed for perforation. Calcium carbonate can be mentioned as the filler, and a known method can be used without limitation as the blending method.

(Three-dimensional gather)
Further, as shown in FIG. 1, the absorbent article 50 has both end portions of the skin side surface of the top sheet 25 along the longitudinal direction of the absorbent article 50 in order to prevent lateral leakage of the body fluid excreted by the user. A pair of three-dimensional gathers 40 are provided. One end of the three-dimensional gather 40 in the width direction of the absorbent article 50 is fixed to the vicinity of both side ends of the skin side surface of the back sheet 30 (or the vicinity of both side ends of the non-skin side surface), and the middle portion in the width direction is the top. The three-dimensional gather sheet is arranged so as to be fixed near both side ends of the skin side surface of the sheet 25 and the other end in the width direction is a free end 40a which is not fixed to the top sheet 25. By providing an elastic elastic member for three-dimensional gathers (not shown) in the vicinity of the free end 40a along the longitudinal direction, the free end 40a of the three-dimensional gather 40 is provided with erectability and can be deformed according to the wearer's body shape. It becomes a thing. The fixed positions of one end in the width direction of the three-dimensional gather 40 are, for example, both ends in the width direction of the non-skin side surface of the back sheet 30, both ends in the width direction of the bag body in which the top sheet 25 and the back sheet 30 are partially or wholly joined. Both ends in the width direction of the skin side surface of the top sheet 25 and the like can be mentioned. The absorbent article of this embodiment also includes an embodiment that does not include three-dimensional gathers.

For example, a polyurethane thread, a strip-shaped polyurethane film, a thread-shaped or strip-shaped natural rubber, or the like is used as the elastic member for the three-dimensional gather, and the three-dimensional gather sheet is water-repellent or liquid-impermeable formed of hydrophobic fibers. Nonwoven fabrics, for example, spunbonded non-woven fabrics, melt-blown non-woven fabrics, composite non-woven fabrics which are laminates of spunbonded non-woven fabrics / melt-blown non-woven fabrics / spunbonded non-woven fabrics, and the like are used.

<Manufacturing method of absorbent articles>
The absorbent article 50 can be manufactured by a known manufacturing method. For example, a step of arranging the absorber 1 between the top sheet 25 and the back sheet 30 and a part or all of the top sheet 25 and the back sheet 30 are used. Manufacturing including a step of fixing with hot melt adhesive, heat embossing, ultrasonic embossing, high frequency embossing, etc. over the circumference, and a step of installing a three-dimensional gather 40 at predetermined positions of the back sheet 30 and the top sheet 25. The method can be mentioned. When the absorbent article 50 is a urine absorbing pad or a light incontinence pad, it may be individually wrapped in a package and then folded in three in the longitudinal direction. In addition, leg gathers, waist gathers, side flaps and the like can be provided as needed.

The absorber 2 shown in FIG. 5 is a modified example of the absorber 1. The absorber 2 uses the same substrate non-woven fabric 11 as the absorber 1, a highly absorbent polymer 12, and a hydrophilic sheet (pulp-containing non-woven fabric) 20, and both ends 20a and 20b of the hydrophilic sheet 20 in the width direction are used. It is further stretched in the width direction so as to overlap on the top sheet 25 side of the substrate nonwoven fabric 11. Due to the presence of the overlapping portion (hereinafter, also referred to as “overlapping region”) of the hydrophilic sheet 20, the absorber 2 does not cause a deterioration in wearing feeling and fit due to the presence of the overlapping region, and is equal to or more than that of the absorber 1. Not only does it show an effect, it also improves the rigidity of the absorber 2 and improves the ability to absorb body fluids. In addition, the diffusion rate and absorption rate of body fluid become even higher. Further, the strength of the absorber 2 is further improved, tearing or breakage of the absorber 2 when it is removed from the body after absorbing the body fluid is further prevented, and the number of repeated absorptions can be further increased.

The width dimension of the overlapping region in the absorber 2 is, for example, a range of 5% or more and 50% or less of the width dimension D of the absorber 2. If it is less than 5%, the effect of improving the diffusion rate and absorption rate of body fluid tends to be insufficient even if the overlapping region is provided. On the other hand, if it exceeds 50%, the diffusion rate and the absorption rate of the body fluid are not improved, but the hardness of the absorber is increased and the wearing feeling and the fitting feeling tend to be deteriorated.

Although the present invention has been described above using the embodiments, it goes without saying that the technical scope of the present invention is not limited to the scope of the invention described in the above embodiments. It will be apparent to those skilled in the art that improvements can be made. Further, it is clear from the description of the scope of claims that the form to which such a modification or improvement is added may be included in the technical scope of the present invention.

Hereinafter, the present invention will be described in detail with reference to examples. The present invention is not limited to the examples shown below.

(Example 1)
First, an air-through non-woven fabric (basis weight 30 g / m ² , bending stiffness 0.018 gf · cm ² / cm, width dimension 60 mm, longitudinal dimension 300 mm) is prepared as the substrate non-woven fabric, and one side surface of the substrate non-woven fabric is surfaced with a rotary saw blade. Physically brushed (thickness after brushing 1.2 mm, brushing rate 25%), highly absorbent polymer is dispersed between the fibers of the brushed part of the base non-woven fabric (basis weight 380 g / m ² ), and hot melt adhesive is applied. It was fixed and supported by an agent. Further, a pulp-containing non-woven fabric (width direction dimension 140 mm, longitudinal direction dimension 300 mm) shown in Table 1 was prepared as a hydrophilic sheet, and the raised surface side of the substrate non-woven fabric and the hydrophilic sheet coated with a hot melt adhesive were adhered to each other. .. Next, the hydrophilic sheet is folded in three, both ends of the hydrophilic sheet are overlapped above the non-raised surface of the substrate non-woven fabric, and the overlapping area is fixed with a hot melt adhesive. An absorber of Example 1 having the structure shown in FIG. 5 was obtained by covering the entire raised surface, both end surfaces in the width direction, and the entire non-raised surface.

Next, an air-through non-woven fabric (basis weight 25 g / m ² ) was used as the top sheet, an air-through non-woven fabric (basis weight 30 g / m ² ) was used as the transfer sheet, and the absorber was used so that the brushed surface faced the back sheet side. A breathable polyethylene sheet (basis weight 30 g / m ² ) is used as a liquid-impermeable back sheet, and a composite non-woven fabric (basis weight 15 g / m 2) which is a laminate of spunbond non-woven fabric / melt blown non-woven fabric / spunbond non-woven fabric is used as a three-dimensional gather. Using m ² ), the absorbent article of Example 1 was prepared.

(Examples 2 to 4)
An absorber and an absorbent article were prepared in the same manner as in Example 1 except that the pulp-containing nonwoven fabric shown in Table 1 was used as the hydrophilic sheet.

(Example 5)
Using the pulp-containing non-woven fabric (dimensions 90 mm in the width direction) shown in Table 1 as the hydrophilic sheet, the hydrophilic sheet is folded in three, and the raised surface, both side end faces in the width direction, and both side ends of the non-brushed surface of the base non-woven fabric are used. An absorber of Example 5 having the structure shown in FIG. 4 was prepared in the same manner as in Example 1 except that regions of 15 mm each in the width direction were covered with a hydrophilic sheet and fixed with a hot melt adhesive. In this absorber, the non-raised surface of the base nonwoven fabric was exposed so as to extend in the longitudinal direction with a width of 60 mm at the central portion in the width direction of the substrate nonwoven fabric.

(Comparative Example 1)
An absorber and an absorbent article were prepared in the same manner as in Example 1 except that the pulp-containing nonwoven fabric shown in Table 1 was used as the hydrophilic sheet.

(Comparative Example 2)
An absorber and an absorbent article were prepared in the same manner as in Example 1 except that the spunbonded nonwoven fabric shown in Table 1 was used as the hydrophilic sheet.

(Comparative Example 3)
An absorber and an absorbent article were prepared in the same manner as in Example 1 except that the crepe paper shown in Table 1 was used as the hydrophilic sheet.

(Comparative Example 4)
A pulp-containing non-woven fabric (dimensions of 60 mm in the width direction) shown in Table 1 was used as the hydrophilic sheet, and an absorber and an absorbent article were prepared in the same manner as in Example 1 except that they were arranged without folding.

(Comparative Example 5)
Air-through non-woven fabric (basis weight 25 g / m ² ) / high-absorbency polymer (basis weight 140 g / m ² ) / air-through non-woven fabric (basis weight 30 g / m ² ) / high-absorbent polymer (basis weight 140 g / m ² ) / span lace A 5-layer laminated sheet (all dimensions in the width direction are 60 mm) in which a non-woven fabric (basis weight 20 g / m ² ) is laminated is used as an absorber of Comparative Example 5, and this is used for the same top sheet and back sheet as in Example 1. An absorbent article of Comparative Example 5 was prepared by interposing it between them. The non-woven fabric used in Comparative Example 5 was not brushed like the substrate non-woven fabric used in Example 1.

[Measurement item]
Using each of the absorbers and the absorbent articles obtained in Examples 1 to 5 and Comparative Examples 1 to 5, the thickness, absorption rate, and amount of reversion were measured, and the results are shown in Table 1.
(Thickness)
The thickness of the center of the absorber was measured under no load condition and under a load condition of 35 gf / cm ^2.
(Absorption rate)
40 ml of 0.9 mass% physiological saline (37 ° C.) was poured into each of the absorbent articles of Examples 1 to 5 and Comparative Examples 1 to 5 ^{from a cylinder having an inner diameter of 30 mm under a pressure of 46 g / cm 2.} The time (seconds) until the physiological saline is absorbed on the surface of the absorber is measured as the first absorption rate. After 3 minutes have passed, 40 ml of 0.9 mass% physiological saline (37 ° C.) is injected again, and the time (seconds) until the physiological saline is absorbed on the surface of the absorber is measured as the second absorption rate. The smaller the value, the better the absorbency.
(Amount of reversion)
100 ml of physiological saline was poured into each of the absorbent articles of Examples 1 to 5 and Comparative Examples 1 to 5, and 90 seconds after the water was poured, the filter paper was pressure-bonded to the surface of the absorber under a load of ^{35 gf / cm 2.} Measure the amount of water that has returned to the filter paper in minutes. The smaller the amount of reversion, the drier the absorber.

Further, each of the absorbent articles of Examples 1 to 5 and Comparative Examples 1 to 5 was subjected to an absorber tear evaluation, an operability evaluation, and a sensory evaluation, and evaluated according to the following evaluation criteria. The results are shown in Table 1.
(Absorber tear evaluation)
Each of the absorbent articles of Examples 1 to 5 and Comparative Examples 1 to 5 was placed on a laboratory table, 100 ml of physiological saline was injected, and 10 minutes after the water was injected, using a 12 kg roller, 30 mm / sec. After reciprocating twice at a speed, the absorber in the absorbent article was confirmed.
〇: Absorber was not torn ×: Absorber was torn and SAP popped out (operability)
〇: Normal production was possible without slowing down the operation speed.
Δ: The speed of operation decreased by 1% or more and 10% or less as compared with the normal case.
X: The operating speed decreased by more than 10% as compared with the normal case.
(sensory evaluation)
Eight panelists were asked to wear each of the absorbent articles of Examples 1 to 5 and Comparative Examples 1 to 5, and the wearing feeling (fitness, softness) and absorbency (presence or absence of leakage to the outside of the absorbent article) Was evaluated by sensory evaluation with two choices, "good" or "bad". The wearer used it for 8 hours and evaluated it in daily activities, and the results are shown in Table 1.
〇: When the number of wearers who chose "good" is 6 or more and 8 or less △: When the number of wearers who chose "good" is 3 or more and 5 or less ×: 1 wearer who chose "good" When there are one or two people, or when there is no wearer who chose "good"

The bending stiffness (flexural rigidity) and wet strength of each hydrophilic sheet were measured by the following methods.
(Bending stiffness)
Bending stiffness (flexural rigidity) was measured by inserting a sample (100 mm × 100 mm) into a fixed chuck and a moving chuck of a bending tester (trade name: KES-FB2, manufactured by Kato Tech Co., Ltd.) and setting them. The moving chuck moves to the maximum positive curvature + 2.5 cm ^-1 and reverses to pass the curvature 0, then ^{moves to the negative maximum curvature -2.5 cm -1} and reverses to end the measurement at 0 curvature. In this way, a reciprocating curve of the bending moment with respect to the curvature of one cycle can be obtained. In the reciprocating curve of bending moment and the stiffness bending an average value of the slope between the slope between the curvature 0.5 cm ^-1 and 1.5 cm ^-1 curvature -0.5Cm ^-1 and -1.5Cm ^-1 ..
(Wet strength Wet tensile strength)
The wet strength (tensile strength when wet) was measured in the CD direction of each hydrophilic sheet based on the tensile test method of JIS8135.

1, 2 Absorbent 10 Highly absorbent sheet 11 Base non-woven fabric 11a Brushed surface 11b Non-raised surface 11x Brushed fiber 11A, 11B Both end faces in the width direction of the base non-woven fabric 12 Highly absorbent polymer 20 Hydrophilic sheet 20a, 20b Width of hydrophilic sheet Direction Both ends 25 Top sheet 30 Back sheet 40 Solid gather 40a Free end of solid gather 50 Absorbent article

Claims (6)

An absorbent article comprising a liquid-permeable top sheet, a liquid-impermeable back sheet, and an absorber disposed between the top sheet and the back sheet.
The absorber is
A base non-woven fabric having a brushed surface and a non-raised surface and arranged so that the non-raised surface faces the top sheet.
A highly absorbent polymer fixedly supported between the raised fibers on the raised surface of the base non-woven fabric,
A hydrophilic sheet covering the raised surface of the base non-woven fabric and
Equipped with a highly absorbent sheet, including
The hydrophilic sheet is
An absorbent article containing a pulp-containing non-woven fabric having a bending stiffness of 0.02 gf · cm ² / cm or more and a wet strength of 10 N / 50 mm or more. The hydrophilic sheet is folded in three so that both end faces in the width direction face each other between the top sheet and the base non-woven fabric and cover both end faces in the width direction of the base non-woven fabric together with the raised surface of the base non-woven fabric. The absorbent article according to claim 1, which has a three-dimensional shape. The hydrophilic sheet is stretched in the width direction so that both ends in the width direction cover the non-raised surface of the substrate nonwoven fabric and overlap each other, and the overlapping width dimension is 5% or more and 50% or more of the width dimension of the absorber. % Or less, the absorbent article according to claim 1. The absorbent article according to any one of claims 1 to 3, wherein the pulp-containing nonwoven fabric has a basis weight of 30 g / m ² or more and 80 g / m ^{2 or less.} The substrate nonwoven fabric is an air-through nonwoven fabric, the basis weight of the air-through nonwoven fabric is 20 g / m ² or more and 80 g / m ² or less, and the thickness of the fibers constituting the air-through nonwoven fabric is 1.6 dtex or more and 14 dtex or less. , The absorbent article according to any one of claims 1 to 4. The absorbent article according to any one of claims 1 to 5, wherein the highly absorbent polymer has a basis weight of 150 g / m ² or more and 800 g / m ^{2 or less in the highly absorbent sheet.}

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