CN115484911B

CN115484911B - Absorbent article

Info

Publication number: CN115484911B
Application number: CN202180031592.1A
Authority: CN
Inventors: 芥川晃士; 富田美奈; 幸田拓也
Original assignee: Kao Corp
Current assignee: Kao Corp
Priority date: 2020-08-18
Filing date: 2021-07-26
Publication date: 2023-11-07
Anticipated expiration: 2041-07-26
Also published as: JP7438889B2; JP2022034251A; WO2022038965A1; CN115484911A

Abstract

The invention provides an absorbent article having a front sheet and an absorber. The front sheet is disposed on the skin side of the wearer. The absorber is disposed on the non-skin side of the front sheet. The front sheet has a nonwoven fabric layer having a structure in which a plurality of protrusions protruding toward the skin of the wearer are arranged at intervals. The nonwoven layer contains a skin care agent. The convex portion has a top and a shoulder, and a contact angle of the top with physiological saline is larger than that of the shoulder, and is larger after passing liquid than before passing liquid with respect to the contact angle at the top before and after passing liquid, and is smaller after passing liquid than before passing liquid with respect to the contact angle at the shoulder before and after passing liquid.

Description

Absorbent article

Technical Field

The present invention relates to an absorbent article such as a disposable diaper.

Background

When wearing an absorbent article such as a disposable diaper, a sanitary napkin, a panty liner (a pad for excretions), or an incontinence pad, rash may occur on the skin due to stuffiness or the like. Therefore, in order to provide skin care effects and to suppress the occurrence of rash, there has been proposed an absorbent article comprising a skin care agent.

For example, patent document 1 describes an absorbent article in which a skin care agent is used in a front sheet that contacts the skin of a wearer.

Prior art literature

Patent literature

Patent document 1: japanese patent laid-open No. 2015-171649

Disclosure of Invention

Technical problem to be solved by the invention

An absorbent article according to one embodiment of the present invention includes a front sheet and an absorber.

The front sheet is disposed on the skin side of the wearer.

The absorber is disposed on the non-skin side of the front sheet.

The front sheet has a nonwoven fabric layer having a structure in which a plurality of protrusions protruding toward the skin of the wearer are arranged at intervals.

The nonwoven layer contains a skin care agent.

The convex portion has a top and a shoulder, and a contact angle of the top with physiological saline is larger than that of the shoulder, and is larger after passing liquid than before passing liquid with respect to the contact angle at the top before and after passing liquid, and is smaller after passing liquid than before passing liquid with respect to the contact angle at the shoulder before and after passing liquid.

Drawings

Fig. 1 is a schematic plan view showing an example of a disposable diaper according to an embodiment of the absorbent article of the present invention, wherein the elastic members of the respective portions are stretched and spread to a flat state on the skin side (front sheet side).

Fig. 2 is a schematic cross-sectional view taken along line II-II of fig. 1.

Fig. 3 is a schematic perspective view showing a part of the front sheet of the disposable diaper in an enlarged manner.

Fig. 4 is a schematic partially enlarged sectional view of the front sheet for explaining the structure of the convex portion of the front sheet.

Fig. 5 is a schematic partial enlarged view showing the skin of a wearer wearing an absorbent article and a surface portion of a front sheet.

Fig. 6 is a schematic partially enlarged view showing the vicinity of the front sheet, the intermediate sheet and the absorbent body of the absorbent article, and is a diagram illustrating the direction of liquid from the wearer.

Fig. 7 is a diagram showing physical properties of nonwoven fabric layers of examples 1 and 2.

Fig. 8 is a diagram showing physical properties of nonwoven fabric layers of comparative examples 1 and 2.

Detailed Description

In general, when a hydrophilic skin care agent is used for the front sheet of an absorbent article, the liquid of the excreta of the wearer absorbed by the front sheet tends to easily return to the skin side. In addition, in the case of using a hydrophobic skin care agent for the front sheet, there is a tendency that the liquid of excrement is hardly absorbed by the front sheet.

As described above, when a skin care agent is used in the front sheet, there is a case where the original liquid permeability and liquid rewet of the front sheet are affected, and there is room for improvement.

The present invention relates to an absorbent article having a skin care agent, which can maintain the liquid permeability of a front sheet satisfactorily and has less liquid return.

Hereinafter, the absorbent article of the present invention will be described with reference to the drawings, taking a disposable diaper as an example.

< integral Structure of Disposable diaper >

As shown in fig. 1, the disposable diaper 1 of the present embodiment is a so-called developed disposable diaper. The disposable diaper 1 has a longitudinal direction X corresponding to the front-rear direction of the wearer and a lateral direction Y corresponding to the right-left direction of the wearer and orthogonal to the longitudinal direction X. Further, the disposable diaper 1 has a thickness direction Z orthogonal to both the longitudinal direction X and the lateral direction Y. In the present specification, each structure as seen from the direction of the thickness direction Z is referred to as a plan view (plan view). In the present specification, the skin side of each structure means a side on the skin side of the wearer when the disposable diaper is worn. The non-skin side of each structure means a side of the disposable diaper which is located opposite to the skin side of the wearer when the disposable diaper is worn. In the thickness direction Z, the side closer to the skin of the wearer when worn is referred to as the upper side, and the side closer to the clothing worn is referred to as the lower side. The disposable diaper 1 is hereinafter referred to as diaper 1.

The diaper 1 is divided into a abdomen-side region a located on the abdomen-side in the longitudinal direction X, a back-side region B located on the back-side in the longitudinal direction X, and a crotch region C located between the abdomen-side region a and the back-side region B.

The back side region B includes side portions protruding outward in the left-right lateral direction Y from the crotch region C. A fastening tape 6 is provided on a side edge portion of the lateral portion Y. Similarly, the abdomen-side region a includes a side portion protruding outward in the lateral direction Y from the crotch region C. A fastening tape (not shown) for engaging the fastening tape 6 is provided on the non-skin side surface of the abdomen-side region a. The back region B and the abdominal region a are joined to each other by the fastening tape 6 when worn, and are integrally disposed around the waist and the waist of the wearer.

The crotch region C is formed so as to be narrower than the width of the abdomen-side region a and the back-side region B, and is disposed in the crotch portion including the urination portion and anus of the wearer when worn, so as to form a leg periphery recessed inward in the lateral direction Y.

The term "wearing" as used herein means a state in which a proper wearing position generally envisaged is maintained.

As shown in fig. 1 and 2, the diaper 1 includes a front sheet 2, a back sheet 3, an absorber 4, side sheets 5, a pair of fastening tapes 6, a middle sheet 7, and a leakage preventing sheet 8. The diaper 1 has a structure in which a back sheet 3, a leakage preventing sheet 8, an absorber 4, an intermediate sheet 7, and a front sheet 2 are laminated in the thickness direction Z. These constituent members are bonded to each other by a known bonding method such as a hot melt adhesive.

The absorber 4 extends in the longitudinal direction X and is disposed between the front sheet 2 and the back sheet 3. That is, the absorber 4 is disposed on the non-skin side of the front sheet 2. The absorber 4 absorbs liquid excrement (hereinafter, may be simply referred to as "liquid") such as urine of the wearer from the surface of the front sheet 2 side, and diffuses the liquid inside to hold the liquid.

The absorbent body 4 has an absorbent core 40 and a core wrap 41.

The absorbent core 40 is mainly composed of an absorbent material capable of retaining a liquid. Specifically, the absorbent core 40 has a fiber-assembled body of hydrophilic fibers, a structure in which an absorbent polymer is supported by the fiber-assembled body, or a structure composed only of an absorbent polymer.

The core wrap 41 covers the absorbent core 40 and has a function of maintaining the shape of the absorbent core 40, for example. The core wrap 41 is formed of, for example, a tissue-like thin and flexible paper, a liquid-permeable nonwoven fabric, or the like.

The front sheet 2 is disposed on the skin side of the wearer. The front sheet 2 is disposed on the skin side (above the thickness direction Z) of the absorber 4, for example, at the center in the lateral direction Y of the skin side surface constituting the diaper 1. The front sheet 2 is a liquid-permeable sheet, and is formed of a nonwoven fabric or the like composed of synthetic fibers or natural fibers. The details of the front sheet 2 will be described later.

The intermediate sheet 7 is disposed between the front sheet 2 and the absorber 4. The nonwoven fabric obtained by various methods can be used for the intermediate sheet 7. The intermediate sheet 7 is disposed from the viewpoints of, for example, improving the liquid permeability from the front sheet 2 to the absorber 4, and preventing the liquid absorbed by the absorber 4 from returning to the front sheet 2. The detail of the intermediate sheet 7 will be described later.

The back sheet 3 is disposed on the non-skin side (lower side in the thickness direction Z) of the absorber 4, and forms, for example, substantially the entire non-skin side surface of the diaper 1, thereby forming an outer body of the diaper 1 when worn. The back sheet 3 is preferably made of a sheet having a leak-proof property, for example, a function such as liquid impermeability, water vapor permeability, or water repellency.

The pair of side sheets 5 are disposed on the lateral Y side portion of the front sheet 2, for example, the lateral Y side portion constituting the skin side surface of the diaper 1. The side sheet 5 is preferably made of a sheet having a liquid-impermeable property, a water vapor-permeable property, a water-repellent property, and the like. In the pair of side sheets 5, the lateral Y center portion side is disposed so as to overlap the front sheet 2, and the lateral Y side portion extends to the outside of the front sheet 2 and is joined to the back sheet 3.

In the diaper 1, the side sheet 5 constitutes a sheet for forming three-dimensional gathers. The side end portion on the side of the lateral direction Y center portion of the side sheet 5 becomes a free end portion which is not joined to the front sheet 2 or the like at least in the crotch region C, and an elastic member 51 is disposed. The elastic member 51 extends in the crotch region C in the longitudinal direction X, and may extend to a part of the abdominal side region a and the back side region B, for example. By providing the elastic member 51, a three-dimensional wrinkle can be formed.

In the vicinity of the lateral end portion on the lateral side of the side sheet 5, for example, an elastic member 52 that stretches and contracts in the longitudinal direction X is arranged, whereby leg gathers that fit around the leg of the wearer when worn are constituted.

The elastic members 51 and 52 are filament-like or band-like elastic members that are stretchable in the longitudinal direction X.

The pair of fastening tapes 6 has fastening portions 61 formed of male members of mechanical surface fasteners. On the non-skin side surface of the abdomen-side region a of the diaper 1, a fastening tape composed of a female member of a mechanical surface fastener is provided. The fastening portion 61 of the fastening tape 6 can be detachably fastened to the fastening tape.

The leakage preventing sheet 8 is made of a liquid impermeable or liquid impermeable resin film and covers the skin side surface of the back sheet 3.

< front sheet >

[ Structure of front sheet ]

As shown in fig. 2 to 4, the front sheet 2 is formed by laminating a lower layer 22 and an upper layer 21 formed on the lower layer 22. The upper layer 21 is composed of a three-dimensional nonwoven fabric layer (hereinafter simply referred to as "nonwoven fabric layer") having a structure in which a plurality of protruding portions 23 are arranged to be spaced apart from each other. The convex portion 23 protrudes in a dome shape toward the skin side of the wearer. The upper layer 21 and the lower layer 22 are bonded and fixed by partial thermal welding at a large number of bonding portions 24. The joint 24 constitutes a base of the front sheet 2 having a plurality of projections spaced apart from each other. In addition, when the joint portion 24 is formed by embossing, a recess (concave portion) is formed in a part of the base portion, and a boundary portion between the convex portion 23 and the concave portion becomes the base portion of the convex portion 23. Non-joined portions other than the joined portion 24 of the upper layer 21 form a convex portion 23. The inside of the convex portion 23 is formed as a hollow. The upper layer 21 has a skin side surface 21a located on the skin side of the wearer when the diaper 1 is worn, and a non-skin side surface 21b located on the opposite side of the skin side surface 21 a.

The joint portions 24 constituting the convex portions 23 and the concave portions are arranged alternately in such a manner as to form rows in one direction (the longitudinal direction X in fig. 3), and such rows are formed in a plurality of rows in a direction (the lateral direction Y in fig. 3) orthogonal to the one direction.

As shown in fig. 4, the boss 23 has a top 26 and a shoulder 27. In the present specification, the top 26 of the convex portion 23 is a portion above 1/2 of the entire height of the convex portion 23 in the thickness direction Z of the front sheet 2. The shoulder 27 of the protruding portion 23 is a lower portion of 1/2 or less of the entire height of the protruding portion 23 in the thickness direction Z. In the diaper 1, the entire height of the protruding portion 23 is a height from the upper surface of the joint portion 24 to the top of the protruding portion 23 in the thickness direction Z.

The upper layer 21 and the lower layer 22 are each made of a sheet of fibrous material. The flap is substantially non-stretchable. As the sheet-like material, various nonwoven fabrics such as nonwoven fabrics, spunbond nonwoven fabrics, meltblown nonwoven fabrics, spunlaced nonwoven fabrics, and needle punched nonwoven fabrics manufactured by the carding method can be used.

The top layer 21 and the bottom layer 22 are partially joined at the joint portion 24 by thermal fusion, and the front sheet 2 having a laminated structure including a plurality of convex portions 23 can be manufactured by a manufacturing method described in japanese patent application laid-open No. 2004-174234, for example.

That is, the sheet-like material of the nonwoven fabric as the upper layer 21 is sandwiched between 2 gear rolls having a concave-convex shape on the peripheral surface thereof, and the sheet-like material is stretched at intervals, and concave-convex shaping is performed. In the sheet thus roughened, the extended portion constitutes the convex portion 23. On the other hand, the portion that does not extend constitutes the joint portion 24 when the front sheet 2 is used. The sheet as the upper layer 21 formed with the plurality of projections 23 is overlapped with the sheet as the lower layer 22, and the overlapped structure is partially joined by being sandwiched between 2 rolls at least one of which is heated to a predetermined temperature. Thus, the upper layer 21 and the lower layer 22 are partially joined by thermal fusion at the joint portion 24, and the front sheet 2 is manufactured. The upper layer 21 side surface of the front sheet 2 has irregularities. On the other hand, the lower layer 22 side surface of the front sheet 2 is substantially flat.

The convex portion 23 of the upper layer 21 thus manufactured has a structure in which the fiber density of the shoulder portion 27 is higher than that of the top portion 26 by the extension process. As shown in fig. 5, when the diaper 1 is worn, the skin 9 of the wearer mainly contacts the top 26 of the convex portion 23. In the convex portion 23, the fiber density of the top portion 26 is relatively small, so that the contact surface of the front sheet 2 with the skin of the wearer can be made soft. This makes it possible to provide a good touch feeling to the skin and to suppress skin problems such as reddening of the skin 9 covered with the diaper 1 due to friction with the front sheet 2. Further, the joint 24 has a higher fiber density than the convex portion 23, and is easy to introduce liquid and has high liquid absorbency.

[ physical Properties of front sheet ]

The physical properties related to the hydrophilicity and hydrophobicity of the upper layer 21 and the lower layer 22 constituting the front sheet 2, which will be described below, can be adjusted by the type of the fiber treating agent, the type and amount of the skin care agent contained, the method of applying the skin care agent, and the like.

Skin care agents are materials that exhibit skin care effects. The "skin care effect" means all functions of preventing rash of skin, diminishing inflammation, preventing injury, resisting bacteria, etc., which maintain the normal state of skin. In the present embodiment, the skincare agent provides a skincare effect to the wearer, and is used to adjust the physical properties concerning the hydrophilicity and hydrophobicity of the nonwoven fabric layer having the plurality of convex portions 23 and the lower layer 22 constituting the upper layer 21 of the front sheet 2.

Regarding the contact angle with physiological saline (0.9% aqueous nacl solution) at the convex portion 23 of the front sheet 2, the top portion 26 is larger than the shoulder portion 27. In this specification, the "contact angle with physiological saline" is simply referred to as a contact angle, and the contact angle with water (ion-exchanged water) is directly referred to as a "contact angle with water". That is, the convex portion 23 has a shoulder 27 having relatively higher hydrophilicity (small contact angle) than the tip 26, and a tip 26 having relatively lower hydrophilicity (large contact angle) than the shoulder 27. In other words, the top 26 exhibits higher hydrophobicity than the shoulder 27, and the shoulder 27 exhibits higher hydrophilicity than the top 26.

Thus, the liquid from the wearer preferentially adheres to the shoulder 27 having relatively high hydrophilicity, and easily moves from the shoulder 27 to the convex portion 23, and the liquid permeability of the front sheet 2 can be improved. Further, since the top portion 26 is relatively high in hydrophobicity, the liquid return can be suppressed. That is, the liquid absorbed by the front sheet 2 is so-called liquid return, in which the liquid absorbed into the front sheet 2 returns to the skin side due to, for example, squeezing from the wearer by a posture such as sitting. However, since the top portion 26 of the front sheet 2 according to the present embodiment mainly contacts the skin of the wearer has high hydrophobicity, the liquid absorbed into the front sheet 2 can be suppressed from returning to the skin side by the top portion 26, and the amount of returning liquid can be reduced. By suppressing the liquid return, the hydration of the skin is suppressed, and the occurrence of skin problems such as reddening of the skin in the diaper 1 can be suppressed.

From the viewpoint of more effectively exerting the above-described effects, the difference in contact angle between the top 26 and the shoulder 27 of the convex portion 23 is preferably 2 ° or more, particularly preferably 5 ° or more, and preferably 70 ° or less, more preferably 30 ° or less, in the former-latter representation, before the liquid is passed through.

In the front sheet 2 of the present embodiment, the contact angle of the top portion 26 of the convex portion 23 of the upper layer 21 changes before and after the liquid passage, and is larger than before the liquid passage. On the other hand, the contact angle of the shoulder 27 of the convex portion 23 changes before and after the liquid passage, and is smaller than before the liquid passage.

In such a configuration, the hydrophobicity of the top 26 of the convex portion 23 increases and the hydrophilicity of the shoulder 27 increases with the passage of liquid such as urination.

Since the liquid is passed through the shoulder portion 27 and the hydrophilicity becomes higher, the liquid from the wearer is stably and efficiently absorbed from the shoulder portion 27 into the front sheet 2 during use of the diaper 1 for a long period of time, and the liquid permeability of the front sheet 2 can be maintained. Further, since the water repellency of the top portion 26 is increased by passing the liquid, the liquid return suppressing effect can be maintained even in the long-term use of the diaper 1.

Therefore, the diaper 1 having the front sheet 2 includes the nonwoven fabric layer (upper layer) having the physical properties described above, and can maintain the liquid permeability of the front sheet 2 well and reduce the liquid return even in long-term use. By suppressing the liquid return, the hydration of the skin can be suppressed, and the occurrence of skin problems such as reddening of the skin in the diaper 1 can be suppressed.

Here, "liquid passing" refers to a case where liquid of excrement such as urine of the wearer is supplied to the front sheet 2.

From the viewpoint of more effectively exerting the above-described effects, the contact angle of the top 26 of the convex portion 23 after passing the liquid is preferably 2 ° or more, more preferably 8 ° or more, and preferably 40 ° or less, more preferably 20 ° or less, with respect to the contact angle before passing the liquid.

From the same point of view, the contact angle of the shoulder 27 of the convex portion 23 after passing the liquid is preferably smaller by 1 ° or more, more preferably smaller by 5 ° or more, and is preferably smaller by 30 ° or less, more preferably smaller by 20 ° or less than the contact angle before passing the liquid.

In the front sheet 2 of the laminated structure, the skin care agent of the upper layer 21 is preferably present at a higher density than that of the lower layer 22. By increasing the presence density of the skin care agent in the upper layer 21 located closer to the skin of the wearer, the skin transfer rate of the skin care agent can be increased, and the use efficiency of the skin care agent can be improved.

In the front sheet 2 of the laminated structure, the contact angle of the lower layer 22 is preferably smaller than the shoulder 27 of the convex portion 23 of the upper layer 21. In other words, the contact angle of the shoulder 27 of the convex portion 23 of the upper layer 21 is larger than that of the lower layer 22 and smaller than that of the top portion 26. Thereby, the liquid from the wearer is absorbed by the lower layer 22 more easily than by the upper layer 21, and the movement of the liquid to the absorber 4 becomes faster. Therefore, the liquid permeation characteristics of the front sheet 2 are improved, and the liquid return suppressing effect is further improved.

From the viewpoint of more effectively exhibiting the above-described effects, the contact angle of the lower layer 22 is preferably 2 ° or more, more preferably 5 ° or more, smaller than the shoulder 27 of the convex portion 23, and the upper limit value is preferably 70 ° or less, more preferably 50 ° or less.

The upper layer 21 including the plurality of convex portions 23 having the physical properties in which the contact angle of the shoulder portion 27 is smaller than the contact angle of the top portion 26 and the shoulder portion 27 before and after the liquid passage are changed in the above-described manner can be manufactured by adjusting the type of the fiber treating agent to be used, the type or amount of the skin care agent to be contained, the method of applying the skin care agent, and the like.

The lower layer 22 having physical properties such that the contact angle of the shoulder 27 of the convex portion 23 of the upper layer 21 is larger than that of the lower layer 22 and smaller than that of the top portion 26 can be produced by adjusting the type of the fiber treating agent, the type or amount of the skin care agent to be contained, and the like.

An example of the method of manufacturing the front sheet 2 will be described later.

[ contact Angle, fiber Density, density of skin-care agent present ]

Specific values of the contact angle and the fiber density are listed below, but these are merely examples and are not limited thereto.

The contact angle θ1 of the top 26 before passing the liquid is preferably 130 ° or more, more preferably 135 ° or more, and preferably 170 ° or less, more preferably 165 ° or less, more specifically, preferably 130 ° or more and 170 ° or less, more preferably 140 ° or more and 165 ° or less.

The contact angle θ2 of the shoulder 27 before passing the liquid is preferably 90 ° or more, more preferably more than 90 °, further preferably 95 ° or more, and preferably 130 ° or less, more preferably 125 ° or less, more specifically, preferably 90 ° or more and 130 ° or less, more preferably more than 90 ° and 130 ° or less, further preferably 95 ° or more and 125 ° or less.

The contact angle θ1' of the top portion 26 after passing the liquid is preferably 140 ° or more, more preferably 145 ° or more, and preferably 170 ° or less, more preferably 165 ° or less, more specifically, preferably 140 ° or more and 170 ° or less, more preferably 145 ° or more and 165 ° or less, on the premise that the contact angle θ1 before passing the liquid is larger.

The contact angle θ2' of the shoulder 27 after passing the liquid is preferably 90 ° or more, more preferably 95 ° or more, and preferably 140 ° or less, more preferably 135 ° or less, more specifically, preferably 90 ° or more and 140 ° or less, more preferably 95 ° or more and 135 ° or less, on the premise that the contact angle θ2 before passing the liquid is smaller.

The contact angle θ3 of the lower layer before passing the liquid is preferably 50 ° or more, more preferably 55 ° or more, and is preferably 85 ° or less, more preferably 80 ° or less, more specifically, preferably 50 ° or more and 85 ° or less, and more preferably 55 ° or more and 80 ° or less.

The method of measuring the contact angle is described later.

The value of the fiber density at the top 26 of the convex portion 23 of the upper layer 21 was 30 pieces/mm ² 130 roots/mm above ² Hereinafter, it is preferably 50 roots/mm ² Above 120 roots/mm ² The following is given.

The value of the fiber density of the shoulder 27 was 80 pieces/mm ² Above 250 roots/mm ² Hereinafter, it is preferably 90 roots/mm ² Above 240 roots/mm ² The following is given.

The value of the fiber density of the concave portion as the joint 24 was 250 pieces/mm ² Above 500 roots/mm ² Hereinafter, 270 roots/mm are preferable ² Above and 480 roots/mm ² The following is given.

The method for measuring the fiber density is described later.

The upper layer skin care agent has a density of 3 μg/cm ³ Above and 500 μg/cm ³ Hereinafter, it is preferably 4. Mu.g/cm ³ Above and 300 μg/cm ³ The following is given.

The skin care agent in the lower layer had a value of 3. Mu.g/cm ³ Above and 500 μg/cm ³ Hereinafter, it is preferably 4. Mu.g/cm ³ Above and 300 μg/cm ³ The following is given.

The method for measuring the presence density of the skin care agent is described later.

< skin-care agent >

As the skin care agent, a hydrophobic skin care agent, a hydrophilic skin care agent, or the like can be used.

The hydrophobic skin care agent is a composition or a compound which does not have a hydrophobic component having water solubility and water dispersibility or very low solubility, and has an effect of protecting and curing the skin of the wearer. More specifically, the hydrophobic component is a component which is dissolved in an amount of less than 1g, preferably 0.1g or less, and particularly preferably not dissolved at all, by mixing 10g of the preparation of the component with 1L of ion-exchanged water and allowing the mixture to stand for 24 hours.

Examples of the hydrophobic skin care agent include fatty acids having a carbon chain length of 12 to 28, or ester compounds of the fatty acids and glycerin, or waxes, and vaseline, and particularly preferably unsaturated fatty acids having a carbon chain length of 12 to 28, or glyceride compounds of the unsaturated fatty acids. The glyceride is a monoester, diester or triester of glycerol and the above-mentioned unsaturated fatty acid, and particularly preferably a triester. As the preparation containing fatty acid or fatty acid compound, natural extract components such as Argan Oil and shea butter can be preferably used. In particular, the argan oil, which is a hydrophobic vegetable oil containing an unsaturated fatty acid, can keep the balance between moisture and oil in the skin and prevent dryness, and thus functions as a skin care agent. In addition, the argin oil contains a large amount of unsaturated fatty acids such as oleic acid and linoleic acid, and has a high active oxygen removing ability, for example, to reduce skin damage caused by sun exposure.

On the other hand, the hydrophilic skin care agent is a skin care agent having a water-soluble or water-dispersible hydrophilic component, and preferably is one which suppresses the occurrence of rash or inflammation, and when the occurrence of rash or inflammation occurs, suppresses the development of the rash or inflammation, or can alleviate the rash or inflammation. More specifically, the hydrophilic component is a component having a dissolution amount or dispersion amount of 1g or more, preferably 5g or more, more preferably 1g or more, still more preferably 5g or more, and most preferably completely dissolved, after 10g of the preparation of the component is mixed with 1L of ion-exchanged water and allowed to stand for 24 hours.

As the hydrophilic skin care agent, natural extract components such as peach leaf extract and witch hazel extract, polyhydric alcohol having 2 to 4 carbon atoms, polyethylene glycol, hydrophilic compound having skin care function, and the like can be used.

Among them, peach leaf extract (hydrophilic extract) as a plant extract is preferable because it has antibacterial and anti-inflammatory effects. The peach leaf extract as a hydrophilic component is dissolved in the liquid supplied to the front sheet 2 and moves to the skin to exert a skin care effect.

The polyhydric alcohol having 2 to 4 carbon atoms is a hydrophilic component, typically 1, 3-butanediol. By using 1, 3-butanediol, the moisturizing effect and lubricity are improved. The lubricity is improved, so that friction between the skin and the nonwoven fabric can be reduced, and damage to the skin can be suppressed. 1, 3-butanediol is a liquid water-soluble base component with moisture retention, and has dry and sticky feel and less sticky feel, so as to keep skin moist. 1, 3-butanediol is used as a humectant and also as a solvent. For example, in the case where the peach leaf extract is used as a skin care agent, 1, 3-butanediol can be used as a solvent for the peach leaf extract. The 1, 3-butanediol is exemplified here, but propylene glycol may be used as long as it is a polyol having 2 to 4 carbon atoms and exhibits the same effect. Propylene glycol can also be used as an extraction solvent for peach leaf extract (hydrophilic extract).

The above-mentioned various skin care agents may be used singly or in combination of two or more. For example, at least 2 skin care agent ingredients having different degrees of hydrophilicity and hydrophobicity may be used. Thus, the time for which the skin care effect is exhibited can be shifted according to the dry state before urination, the change in the degree of wet state due to urination or perspiration, or the like, and the skin care effect can be maintained for a long period of time.

In the case of using at least 2 kinds of skin care agent ingredients differing in degree of hydrophilicity and hydrophobicity, it is more preferable to contain a hydrophilic skin care agent (hydrophilic ingredient) and a hydrophobic skin care agent (hydrophobic ingredient). Thus, the hydrophobic skin care agent is easily moved to the skin in the dry state before urination, and the hydrophilic skin care agent dissolved in the liquid at the time of liquid return is easily moved to the skin in the wet state after urination. Therefore, the appearance of the skin care effect can be maintained for a long period of time from the wearing of the diaper 1, and the occurrence of skin problems can be further suppressed.

The skin care agent preferably uses natural extract. For example, since the skin of an infant wearing the diaper 1 is thinner and has a poorer barrier function than an adult, the occurrence of allergic reactions and the like can be suppressed by using natural extract components. In addition, by using the natural product extract component, skin problems such as reddening of the skin in diapers are less likely to occur.

The preferable content per unit area of the skin care agent disposed in the nonwoven fabric layer is as follows. The hydrophilic skin care agent is preferably 0.1 mass% or more and 150 mass% or less relative to the mass of the fiber, and is preferably 0.2 mass% or more and 50 mass% or less from the viewpoint of balance with the feel of use, from the viewpoint of further improving the effect of the present invention. In addition, the hydrophobic skin care agent has a mass of 1×10 relative to the fiber ^-4 More than 0.5 mass%, especially 2X 10 ^-4 When the amount is not less than 0.1% by mass, the effect of the present invention and the feeling of use are more easily balanced, and thus it is preferable.

The hydrophilic oil (fiber treating agent) described in the production method described later is a block of the solid lipid-like active agent at 36 ℃. In contrast, hydrophobic skin care agents such as alaglycerol, hydrophilic skin care agents such as peach leaf extract or 1, 3-butanediol are liquid at 36 ℃. By using the hydrophilic oil agent, the liquid hydrophobic skin care agent and hydrophilic skin care agent can be stably attached to the fibers.

< intermediate sheet >

As shown in fig. 6, the intermediate sheet 7 has a first surface 71 positioned on the skin side of the wearer and a second surface 72 positioned on the opposite side of the first surface 71.

The fiber density of the intermediate sheet 7 made of hydrophilic nonwoven fabric is distributed in the thickness direction Z, and the fiber density on the first surface 71 side is smaller than the fiber density on the second surface 72 side. Since the capillary tube has a high force of introducing the liquid when the fiber density is high (the fiber density is high), the liquid from the wearer moving from the front sheet 2 to the intermediate sheet 7 is introduced to the second surface 72 by configuring the intermediate sheet 7 such that the fiber density thereof is lower on the first surface 71 side than on the second surface 72 side, and the liquid is less likely to remain on the first surface 71 side of the intermediate sheet 7. This can suppress the elution of the skin care agent from the front sheet 2 to the intermediate sheet 7 due to the liquid residue after urination, and can ensure the skin care agent moving to the skin, thereby maintaining the skin care effect.

The intermediate sheet 7 and the front sheet 2 are bonded and fixed to each other by a first adhesive 11 made of a hot melt adhesive or the like disposed on the first surface 71. The intermediate sheet 7 and the absorber 4 are bonded and fixed by a second adhesive 12 made of a hot melt adhesive or the like disposed on the second surface 72.

The first adhesive 11 is disposed at intervals so as not to interfere with the smooth movement of the liquid from the front sheet 2 to the intermediate sheet 7, and so as to generate a non-application region of the adhesive. The second adhesive 12 is disposed at intervals so as not to interfere with the smooth movement of the liquid from the intermediate sheet 7 to the absorbent body 4, and so as to generate a non-application region of the adhesive. The first adhesive 11 and the second adhesive 12 are arranged in a plurality at intervals in the lateral direction Y and in a strip shape along the longitudinal direction X, for example.

The coating area ratio of the first adhesive 11 is lower than that of the second adhesive 12. Specifically, the application area ratio of the first adhesive 11 is preferably 5% or more and 50% or less, more preferably 7% or more and 30% or less. The application area ratio of the second adhesive 12 is preferably 10% or more and 65% or less, more preferably 13% or more and 50% or less. The method for measuring the coating area ratio is described later.

The second adhesive 12 overlaps at least a part of the shoulder 27 of the protruding portion 23 in plan view.

Since the application area ratio of the first adhesive 11 is lower than that of the second adhesive 12, the movement of the liquid from the intermediate sheet 7 to the absorber 4 becomes slower than the movement of the liquid from the front sheet 2 to the intermediate sheet 7, and the liquid is temporarily stored in the intermediate sheet 7 before being absorbed by the absorber 4. In the present embodiment, the shoulder 27 of the front sheet 2, which is likely to absorb liquid from the wearer, overlaps with the second adhesive 12 in a plan view, and as shown by the arrow in fig. 6, the liquid absorbed from the shoulder 27 is prevented from moving toward the absorber 4 by the second adhesive 12 located immediately below, and spreads laterally in the figure, and is likely to be accumulated in the intermediate sheet 7 before being absorbed by the absorber 4. Thus, when the liquid temporarily accumulated in the intermediate sheet 7 returns, the hydrophilic skin care agent dissolves into the liquid and the skin care agent moves to the skin, so that the skin care agent can be effectively used and the skin care effect can be maintained.

[ method for producing front sheet ]

A specific method for producing the front sheet having the above physical properties will be described. The front sheet 2 of the present embodiment can be manufactured by overlapping the upper layer 21 manufactured by the manufacturing method of the first to sixth examples described later and the lower layer 22 manufactured by the manufacturing method described later, and partially joining the two layers by the above-described method. By the manufacturing method of the first to sixth examples described later, a nonwoven fabric layer (upper layer) having a plurality of protruding portions 23 can be manufactured, and the plurality of protruding portions 23 have physical properties in which the contact angle of the shoulder portion 27 is smaller than that of the top portion 26, and the contact angle of each of the top portion 26 and the shoulder portion 27 before and after passing liquid is changed as described above. The manufacturing method is not limited to this.

As the raw material fibers of the upper layer 21 and the lower layer 22, core-sheath fibers, parallel composite fibers, and the like can be preferably used, and core-sheath fibers are particularly preferable. As typical fibers, fibers having a core component made of PET (polyethylene terephthalate) and a sheath component made of PE (polyethylene) and having a core-to-sheath ratio of 20/80 to 80/20 by mass are preferable. The fineness of the fibers is preferably 1.5dtex or more and 5.0dtex or less. The core-to-sheath ratio represents the mass ratio of the resins constituting the core and the sheath (core/sheath).

(first example)

For example, a method of producing a nonwoven fabric layer having a plurality of projections by forming a fiber coated with a treating agent into a nonwoven fabric sheet and subjecting the nonwoven fabric sheet to the above-mentioned embossing process is exemplified, wherein the treating agent is composed of a mixture containing a hydrophilic oil agent (fiber treating agent) and a hydrophilic skin care agent (hydrophilic component) and a hydrophobic skin care agent (hydrophobic component). In the case of the embossing, the sheet is stretched relatively strongly at the portions where the projections are formed by the projections of the roller when the sheet is engaged with the gear roller, and the tops of the projections are stretched relatively strongly than the shoulders of the sheet. In this way, the fiber density of the nonwoven fabric layer having a plurality of projections formed thereon is smaller at the top than at the shoulder, and the existing density of the skin care agent is also smaller.

In the convex portion 23 of the nonwoven fabric layer thus produced, the hydrophilic skin care agent is present at a density such that the top portion 26 is smaller than the shoulder portion 27 and the contact angle of the top portion 26 is larger than the shoulder portion 27.

In addition, when the nonwoven fabric layer thus produced is used for the upper layer 21 of the front sheet 2 of the diaper 1, and when a liquid is supplied to the upper layer 21 during wearing of the diaper 1, the hydrophilic skin care agent (hydrophilic component) present in the top portion 26 is dissolved in the liquid supplied to the top portion 26 and flows along with the liquid to the shoulder portion 27. This increases the hydrophobicity of the top portion 26, and increases the contact angle of the top portion 26 after passing the liquid compared with before passing the liquid. On the other hand, the hydrophilicity of the shoulder 27 increases, and the contact angle of the shoulder 27 decreases after passing the liquid as compared with before passing the liquid.

In the nonwoven fabric layer thus produced, the hydrophilic skin care agent has a higher density than the top portion 26 at the shoulder 27. As a result, the front sheet 2 can absorb liquid from the shoulder more quickly, and can have a structure with good liquid permeability.

The "hydrophilic oil agent" is a fiber treatment agent for hydrophilizing the surface of fibers, and is a hydrophilic component, and a known hydrophilic oil agent can be used. In the case of using the peach leaf extract as a hydrophilic skin care agent, 1, 3-butanediol can be used as a solvent for the peach leaf extract, and the treatment agent containing the skin care ingredient contains 1, 3-butanediol.

The nonwoven fabric layer may be produced by forming a nonwoven fabric of fibers coated with a treatment agent containing a skin care component, for example, by forming a nonwoven fabric of fibers coated with a hydrophilic oil agent, performing a surface relief treatment, and then integrally coating a treatment agent containing a hydrophilic skin care agent and a hydrophobic skin care agent. In this case, after the application of the treatment agent, the nonwoven fabric is left to stand for a predetermined period of time (for example, 5 hours at room temperature) so that the hydrophilic skin care agent and the hydrophobic skin care agent are dispersed therein. Thus, a nonwoven fabric substantially similar to a nonwoven fabric obtained by converting a fiber nonwoven fabric coated with a treating agent comprising a mixture of a hydrophilic oil agent and a hydrophilic skin care agent and a hydrophobic skin care agent can be produced. Examples 1, 2 and 1 described later were produced by this production method. The nonwoven fabric obtained by converting the fiber nonwoven fabric coated with the hydrophilic oil agent is a hydrophilic nonwoven fabric.

(second example)

For example, a method of coating a hydrophobic skin care agent by spraying a nonwoven fabric produced from fibers uniformly coated with a hydrophilic oil agent after the uneven surface is formed by the above method. The hydrophobic skin care agent is applied by spraying to the nonwoven fabric after the embossing, and the hydrophobic skin care agent is applied intensively to the top 26 in the convex portion. In addition, a hydrophilic skin care agent may be mixed with the hydrophilic oil agent.

In the convex portion 23 of the nonwoven fabric layer thus produced, the hydrophobic skin care agent is present at a density such that the top portion 26 is larger than the shoulder portion 27, and the contact angle of the top portion 26 becomes larger than the contact angle of the shoulder portion 27.

In addition, when the nonwoven fabric layer thus produced is used for the upper layer 21 of the front sheet 2 of the diaper 1, when a liquid is supplied to the upper layer 21 during wearing of the diaper 1, the hydrophilic skin care agent (hydrophilic component) present at the top portion 26 dissolves in the liquid supplied to the top portion 26 and flows along with the liquid to the shoulder portion 27. As a result, the top portion 26 becomes more hydrophobic, and the contact angle of the top portion 26 becomes larger after the liquid is passed than before the liquid is passed. On the other hand, the shoulder 27 has a higher hydrophilicity, and the contact angle of the shoulder 27 becomes smaller after passing the liquid than before passing the liquid.

(third example)

For example, a method in which a nonwoven fabric produced from fibers uniformly coated with a hydrophilic oil is subjected to uneven processing by the above-described method, and then a hydrophobic skin care agent is applied by an applicator is used. The hydrophobic skin care agent is applied to the nonwoven fabric subjected to the embossing by an applicator, whereby the hydrophobic skin care agent is intensively applied to the top 26 in the convex portions. In addition, a hydrophilic skin care agent may be mixed with the hydrophilic oil agent.

In the convex portion 23 of the nonwoven fabric layer thus produced, the hydrophobic skin care agent is present at a density such that the top portion 26 is larger than the shoulder portion 27, and the contact angle of the top portion 26 is larger than the contact angle of the shoulder portion 27.

In addition, by using the nonwoven fabric layer thus produced for the upper layer 21 of the front sheet 2 of the diaper 1, when the liquid is supplied to the upper layer 21 during wearing of the diaper 1, the hydrophilic skin care agent (hydrophilic component) present in the top portion 26 is dissolved in the liquid supplied to the top portion 26 and flows toward the shoulder portion 27 together with the liquid. Thus, the top portion 26 has higher hydrophobicity, and the contact angle of the top portion 26 increases after passing the liquid compared with before passing the liquid. On the other hand, the shoulder 27 has a higher hydrophilicity, and the contact angle of the shoulder 27 becomes smaller after passing the liquid than before passing the liquid.

(fourth example)

For example, a method is known in which a hydrophobic nonwoven fabric is subjected to concave-convex processing by a gear roller to which a hydrophilic skin care agent is transferred to form concave portions, and the hydrophilic skin care agent is concentrated on the shoulders. In the nonwoven fabric thus manufactured, the contact angle of the top 26 is larger than the shoulder 27 in the convex portion 23. The nonwoven fabric layer is obtained by applying a hydrophobic skin care agent to the top 26 of the nonwoven fabric. The hydrophobic nonwoven fabric may be a nonwoven fabric produced from fibers uniformly coated with a hydrophobic finish.

By using the nonwoven fabric layer thus produced for the upper layer 21 of the front sheet 2 of the diaper 1, when the liquid is supplied to the upper layer 21 during wearing of the diaper 1, the hydrophilic skin care agent (hydrophilic component) present in the top portion 26 is dissolved in the liquid supplied to the top portion 26 and flows along with the liquid to the shoulder portion 27. Thus, the top portion 26 has higher hydrophobicity, and the contact angle of the top portion 26 increases after passing the liquid compared with before passing the liquid. On the other hand, the shoulder 27 has a higher hydrophilicity, and the contact angle of the shoulder 27 becomes smaller after passing the liquid than before passing the liquid.

In the nonwoven fabric layer thus produced, the hydrophilic skin care agent has a higher density of the shoulder 27 than the top 26. As a result, the liquid is absorbed from the shoulder portion of the front sheet 2 more rapidly, and a nonwoven fabric having better liquid permeability can be formed.

In the nonwoven fabric layer thus produced, the skin care agent is applied from the skin side surface side, so that the presence density of the hydrophobic skin care agent is higher on the skin side surface than on the non-skin side surface. Thus, the hydrophobic skin care agent moves to the skin rapidly when the diaper 1 is worn.

(fifth example)

For example, a method is known in which a nonwoven fabric produced from fibers uniformly coated with a hydrophilic finish is subjected to the embossing process by the above-described method, and then a mixture of a hydrophobic skin care agent and a hydrophilic skin care agent is applied to the top of the raised portion. As the coating method, spray coating, applicator coating, or the like can be used, and by these coating methods, a mixture of a hydrophobic skin care agent and a hydrophilic skin care agent can be applied to the convex portion 23 in a concentrated manner on the top portion 26.

The convex portions 23 of the nonwoven fabric layer thus produced have a mixture of the hydrophobic skin care agent and the hydrophilic skin care agent present at a density such that the top portion 26 is greater than the shoulder portion 27. Therefore, in the convex portion 23, more hydrophobic skin care agent (hydrophobic component) is present in the top portion 26 than in the shoulder portion 27, and the contact angle of the top portion 26 becomes larger than the contact angle of the shoulder portion 27.

In addition, by using the nonwoven fabric layer thus produced for the upper layer 21 of the front sheet 2 of the diaper 1, when the liquid is supplied to the upper layer 21 during wearing of the diaper 1, the hydrophilic skin care agent (hydrophilic component) present in the top portion 26 dissolves in the liquid supplied to the top portion 26 and flows toward the shoulder portion 27 together with the liquid. Thus, the top portion 26 has higher hydrophobicity, and the contact angle of the top portion 26 increases after passing the liquid compared with before passing the liquid. On the other hand, the shoulder 27 has a higher hydrophilicity, and the contact angle of the shoulder 27 becomes smaller after passing the liquid than before passing the liquid.

In the nonwoven fabric layer thus produced, the skin care agent is applied from the skin side surface side, so that the hydrophobic skin care agent is present in a higher density on the skin side surface than on the non-skin side surface. Thus, the hydrophobic skin care agent moves to the skin rapidly when the diaper 1 is worn.

(sixth example)

For example, a method of manufacturing a nonwoven fabric layer having a plurality of protrusions by performing the above-described embossing process on a sheet-like material formed of a nonwoven fabric manufactured by superposing a hydrophilic web containing a hydrophilic skin care agent and a hydrophilic oil agent and a hydrophobic web containing a hydrophobic skin care agent. In the case of the embossing, the sheet is stretched relatively strongly at the portion where the convex portion is formed by pressing the convex portion of the roller when the roller is engaged with the gear roller, and the top portion of the convex portion is stretched relatively strongly than the shoulder portion. In the convex portion of the nonwoven fabric layer having a plurality of convex portions, the fiber density is relatively smaller at the top than at the shoulder, and the presence density of the skin care agent is also smaller. The hydrophilic mesh may be produced by forming a fiber nonwoven fabric and then coating a hydrophilic skin care agent and a hydrophilic oil agent, or may be produced by forming a fiber nonwoven fabric coated with a hydrophilic skin care agent and a hydrophilic oil agent. The hydrophobic nonwoven fabric may be produced by forming a fibrous nonwoven fabric and then coating the fibrous nonwoven fabric with a hydrophobic skin care agent, or may be produced by forming a fibrous nonwoven fabric coated with a hydrophobic skin care agent. In addition, the hydrophobic net cloth may contain a hydrophilic oil agent (fiber treating agent) in addition to the hydrophobic skin care agent.

When the nonwoven fabric layer thus produced is used as the upper layer 21 of the front sheet 2, the upper layer 21 is disposed such that the hydrophilic web side forms the skin side surface 21a of the upper layer 21 and the hydrophobic web side forms the non-skin side surface 21b of the upper layer 21 in the diaper 1.

The protrusions 23 of the nonwoven fabric layer used in the upper layer 21 of the diaper 1 are formed with the irregularities in this way, the top 26 is smaller than the shoulder 27, and the contact angle of the top 26 is larger than the contact angle of the shoulder 27 with respect to the presence density of the hydrophilic skin care agent present in the outermost layer.

In addition, when the nonwoven fabric layer thus produced is used for the upper layer 21 of the front sheet 2 of the diaper 1, the hydrophilic skin care agent (hydrophilic component) present in the top portion 26 is dissolved in the liquid supplied to the top portion 26 and flows along with the liquid to the shoulder portion 27 when the liquid is supplied to the upper layer 21 during wearing of the diaper 1. Thus, the top portion 26 has higher hydrophobicity, and the contact angle of the top portion 26 increases after passing the liquid compared with before passing the liquid. On the other hand, the shoulder 27 has a higher hydrophilicity, and the contact angle of the shoulder 27 becomes smaller after passing the liquid than before passing the liquid.

Further, since the hydrophilic web side forms the skin side surface 21a of the upper layer 21 and the hydrophobic web side forms the non-skin side surface 21b of the upper layer 21, the skin side surface 21a exhibits hydrophilicity and the non-skin side surface 21b exhibits hydrophobicity in the upper layer 21 of the front sheet 2. Thus, the contact angle of the non-skin side surface 21b is smaller than that of the skin side surface 21 a. Thus, the hydrophilic skin care agent (hydrophilic component) present in the top portion 26 dissolves due to the liquid from the wearer, and is easily moved to the skin, with good efficiency. In addition, since the liquid absorbed from the shoulder 27 toward the front sheet 2 is suppressed from returning to the skin side by the hydrophobic non-skin side surface 21b, the liquid return suppressing effect can be effectively exhibited.

Here, an example is given in which a nonwoven fabric layer is produced by superposing a hydrophilic web and a hydrophobic web and performing a concave-convex process. Alternatively, a nonwoven fabric layer having a plurality of protrusions may be produced by embossing a sheet-like material made of nonwoven fabric, then applying a hydrophilic skin care agent to the skin side surface side of the top of the protrusions, and applying a hydrophobic skin care agent to the non-skin side surface side of the top.

(production example of lower layer)

The lower layer is formed by using a sheet-like material obtained by nonwoven fabric-forming fibers coated with a hydrophilic oil agent and a hydrophilic skin care agent.

< supplementary explanation >

[ method of measuring contact Angle ]

The measurement of the contact angle of the top of the convex portion and the shoulder portion of the front sheet can be performed in the following manner.

In microscope VH-8000 manufactured by KEYENCE CORPORATION, a medium magnification zoom lens (with an illumination ring) was used in a state of being tilted sideways by 90 °, and measurement was performed under conditions set to 500 times. The measurement sample used was a front sheet cut into a sheet having a size of 150mm in the longitudinal direction and 70mm in the transverse direction. The measurement environment was 20 ℃/50% rh, and the measurement sample was set on the measurement table so that the measurement surface (in this case, the surface having a plurality of convex portions) was oriented upward and was visible from the CD direction of the web (nonwoven fabric). Then, 2. Mu.l of physiological saline was adhered to the top or shoulder of the convex portion of the measurement sample by a micropipette, and an image was obtained within 5 seconds (as much as 2 to 3 seconds) of the adhesion. The reason why it is necessary to take an image in a short time after the adhesion is that the adhered water droplets are evaporated by light emitted from the measuring section of the microscope and the contact angle change by the oil agent is not caused. The contact angle of 10 points was measured as the average value of the contact angles as a "contact angle" from the clear observation of the focus at both ends or one end of the water droplet. The contact angle is measured by drawing a tangent to the fiber of the water droplet for an image or a printed photograph, using image analysis or a protractor, etc.

In addition, although the above measurement is performed with physiological saline, in the case of measuring the "contact angle with water", the same measurement may be performed by replacing physiological saline with ion-exchanged water.

In the measurement of the contact angle between the skin side surface and the non-skin side surface of the upper layer (nonwoven fabric layer), the front sheet having the laminated structure was separated into an upper layer and a lower layer, and the separated upper layer was used as a measurement object, and the skin side surface and the non-skin side surface were used as measurement surfaces, respectively, to perform the same measurement as in the above measurement.

The contact angle of the lower layer was measured, and the same measurement as described above was performed using the skin side surface of the lower layer separated from the front sheet 2 as a measurement surface.

The contact angle with physiological saline or water is an index indicating the degree of hydrophobicity or hydrophilicity of a constituent such as a fiber or an intermediate sheet. The smaller the value of the contact angle with physiological saline or water, the higher the hydrophilicity of the fiber or the constituent can be judged. In general, the contact angle θ with water of a fiber or a constituent classified as hydrophilic is smaller than 90 ° (15 ° or more and smaller than 85 °, particularly preferably 50 ° or more and 83 ° or less in the present invention), and the contact angle θ with water of a fiber or a constituent classified as hydrophobic is larger than 90 ° (90 ° or more and 170 ° or less, particularly preferably 92 ° or more and 165 ° or less in the present invention).

The hydrophilicity of the intermediate sheet can be determined from the contact angle obtained by performing the same measurement as that described above by replacing the physiological saline with ion-exchanged water with the skin side surface of the intermediate sheet as the measurement surface.

The contact angle of each of the liquid before and after passing through the liquid is measured by using the above-described measurement method for each of the liquid before and after passing through the liquid. The liquid-passing condition was such that 90g of physiological saline was passed through the nonwoven fabric at a rate of 5.0 g/sec under no-pressure conditions in a state in which the nonwoven fabric to be measured was placed on the absorbent body. The supply of physiological saline to the nonwoven fabric was performed by guiding the liquid discharge port to the upper side of 10mm of the nonwoven fabric placed on the absorber by a silicone tube and by a liquid injection pump (made by ISMATEC, MCP-J). The absorbent body was used by removing a front sheet from a Merries (registered trademark) tape type S size manufactured by Kagaku corporation, 2020. The supply amount of 90g is an average excretion amount assumed for infants. The feeding rate of 5.0 g/sec was assumed to be the urine excretion rate when the infant excretes.

In the measurement of the contact angle of the skin side surface and the non-skin side surface of the nonwoven fabric layer, the skin side surface and the non-skin side surface of the nonwoven fabric layer (upper layer in the present embodiment) constituting the convex portion of the nonwoven fabric layer having a plurality of convex portions in its entirety are taken out as the measurement target portions, and the fibers of the layer located on the outermost surface of the respective skin side surfaces are taken out for measurement.

[ method of measuring the Density of skin-care agent ]

A method for measuring the density of the skin care agent contained in the front sheet will be described.

A sample of a predetermined size was cut out from the upper layer 21 of the nonwoven fabric layer having a plurality of projections on the whole layer thereof from the front sheet 2, and the sample was observed under magnification (for example, magnification of 150 to 500 times) by a scanning electron microscope (for example, JCM-5100 (trade name) manufactured by japan electronics corporation), and the volumes of the top and shoulder were calculated from the area and thickness of the sample.

The fibers 2g at the top and shoulder of the measurement target portion were collected and placed in a predetermined container having a small opening at the lower portion. After that, the fiber is pressed by the cap, and the fiber is pushed into the lower part of the container, and the cap is removed. To this, a 10cc ether as an extraction solvent for a hydrophobic skin care agent or a 10cc ethanol/methanol (1:1) mixed solution as an extraction solvent for a hydrophilic skin care agent was added, and the mixture was allowed to stand for 6 hours. Then, the cover is closed again, and the fiber containing the solution is strongly pressed, whereby the liquid contained in the fiber, that is, the ether or ethanol/methanol component, is squeezed out, and the squeezed liquid is placed in a weighing pan. Then, after the weighing pan was heated to remove the solvent, the weight of the weighing pan was measured, and the amount of the skin care agent was measured based on the difference between the weight of the weighing pan and the original weight of the weighing pan before the liquid was put in. The skin care agent amounts of 3 samples were measured and averaged as skin care agent attachment amounts.

The density of the skin care agent is calculated based on the calculated volume and the skin care agent adhesion.

In addition, since the hydrophobic skin care agent is extracted in the ethanol/methanol extraction solvent, the extraction of the ether may not be performed in the case where all of the skin care agent contained in each fiber is extracted in the ethanol/methanol extraction solvent.

[ method of measuring fiber Density ]

A method of measuring the density of the fibers constituting the front sheet 2 will be described.

The cut surface of the front sheet 2 was observed under magnification (for example, 150 to 500 times) by a scanning electron microscope (for example, JCM-5100 (trade name) manufactured by Japanese electric Co., ltd.) to count each of the top and shoulder at a constant area (0.5 mm) ² Left and right) the number of cross-sections of the fibers cut by the cut surface. Next, the conversion is performed every 1mm ² Is defined as the fiber density. The measurement was performed at 3 sites, and the average was taken as the fiber density of the sample.

In the measurement of the fiber density of each of the top 26 and the shoulder 27 of the convex portion 23, the hollow portion in the convex portion 23 where no fiber is present is not included.

[ method of measuring coating area Rate ]

A method of measuring the application area ratio of the first adhesive 11 and the second adhesive 12 will be described.

The adhesive was colored by applying a coloring agent to the entire surface of each of the front (skin side) and back (non-skin side) surfaces of the intermediate sheet, and then the colored area was measured by cutting the adhesive to a predetermined size. The measured area is divided by the cut size to obtain the coating area ratio. The measurement area was 3 or more, and the average value was obtained to calculate the coating area ratio.

The embodiments of the present invention have been described above, but the present invention is not limited to the above embodiments, and various modifications are of course possible within the scope of the present invention.

For example, in the above embodiments, the disposable diaper is shown as an example of the absorbent article, but the invention is not limited thereto. The absorbent article of the present invention may be, for example, a urine collection pad, a pad for excretions, a sanitary napkin, or the like. The absorbent article generally comprises a liquid-permeable front sheet, a liquid-impermeable back sheet, and a liquid-retentive absorbent member disposed between the two sheets.

In the above embodiment, the example was described in which the front sheet has a laminated structure in which the upper layer and the lower layer made of the nonwoven fabric layer having the plurality of protrusions are laminated, but may have a single-layer structure in which the nonwoven fabric layer having the plurality of protrusions is 1 layer.

In the front sheet 2, the joint portion 24 between the upper layer 21 and the lower layer 22 located between the plurality of convex portions 23 may be provided with an opening. The openings are holes penetrating the front sheet 2 in the thickness direction Z. The opening is formed at a position further inward than the outline of the joint 24 in a plan view. By providing the opening, the liquid introduction property and the like can be further improved. The openings can be formed by adjusting the temperature and pressure of hot embossing and ultrasonic embossing when the upper layer 21 and the lower layer 22 are bonded by an embossing roller, for example.

<1>

An absorbent article comprising a front sheet disposed on the skin side of a wearer and an absorber disposed on the non-skin side of the front sheet, wherein the front sheet comprises a nonwoven fabric layer having a structure in which a plurality of protrusions protruding toward the skin side of the wearer are disposed at intervals, the nonwoven fabric layer contains a skin care agent, the protrusions have a top portion and a shoulder portion, the contact angle between the top portion and physiological saline is larger than that between the shoulder portion, the contact angle between the top portion and the physiological saline is larger before and after passing through the liquid, the contact angle between the top portion and the physiological saline is larger after passing through the liquid than before passing through the liquid, and the contact angle between the top portion and the shoulder portion is smaller before and after passing through the liquid than before passing through the liquid.

<2> in the absorbent article according to <1>,

the nonwoven fabric layer has a skin side surface and a non-skin side surface opposite to the skin side surface, and the contact angle of the non-skin side surface is smaller than the contact angle of the skin side surface.

<3> in the absorbent article according to <1> or <2>,

the nonwoven layer contains a hydrophilic skin care agent, the hydrophilic skin care agent being present in a greater density in the shoulder than in the top.

<4> in the absorbent article according to any one of <1> to <3>,

the nonwoven fabric layer has a skin side surface and a non-skin side surface opposite to the skin side surface, and the nonwoven fabric layer contains a hydrophobic skin care agent, and the hydrophobic skin care agent on the skin side surface has a higher presence density than the non-skin side surface.

<5> in the absorbent article according to any one of <1> to <4>,

the front sheet includes an upper layer composed of the nonwoven fabric layer and a lower layer composed of nonwoven fabric overlapped on the upper layer.

<6> in the absorbent article of <5>,

the upper layer and the lower layer are partially fixed, and the convex portion is formed by a portion of the upper layer that is not fixed to the lower layer.

<7> in the absorbent article according to <5> or <6>,

the upper layer and the lower layer contain a skincare agent, the skincare agent in the upper layer being present in a greater density than the lower layer.

<8> in the absorbent article according to any one of <5> to <7>,

the contact angle of the shoulder is greater than the contact angle of the underlying layer and less than the contact angle of the top.

<9> in the absorbent article according to any one of <1> to <8>,

the top portion has a lower fiber density than the shoulder portion.

<10> in the absorbent article according to any one of <1> to <9>,

the skin care agent contains at least 2 components with different degrees of hydrophilicity and hydrophobicity.

<11> in the absorbent article of <10>,

at least 1 of the ingredients contained in the skin care agent is hydrophilic.

<12> in the absorbent article according to any one of <1> to <11>,

the skin care agent is natural extract.

<13> in the absorbent article according to any one of <1> to <12>,

the front sheet has openings between the plurality of convex portions.

<14> in the absorbent article according to any one of <1> to <13>,

the front sheet is provided with a non-skin side and an intermediate sheet made of hydrophilic nonwoven fabric, wherein the intermediate sheet has a first surface on the skin side and a second surface on the opposite side of the first surface, and the intermediate sheet on the first surface side has a lower fiber density than the second surface side.

<15> in the absorbent article of <14>,

the first adhesive disposed on the first surface of the intermediate sheet has a smaller application area than the second adhesive disposed on the second surface of the intermediate sheet, and the second adhesive is disposed in plurality at intervals on the second surface, and overlaps at least a part of the shoulder portion of the convex portion in a plan view.

<16> in the absorbent article according to any one of <1> to <15>,

the difference in contact angle between the top portion and the shoulder portion of the convex portion is 2 ° or more, preferably 5 ° or more, when expressed as the former-the latter before passing through the liquid.

<17> in the absorbent article according to <16>,

the difference in contact angle between the top portion and the shoulder portion of the convex portion is 2 ° or more and 70 ° or less, preferably 5 ° or more and 30 ° or less, when expressed as the former-the latter before passing through the liquid.

<18> in the absorbent article according to any one of <1> to <17>,

the contact angle of the top of the convex portion after the liquid passage is larger by 2 ° or more, preferably by 8 ° or more than the contact angle before the liquid passage.

<19> in the absorbent article of <18>,

The contact angle of the top of the convex portion after passing the liquid is larger by 2 ° or more and 40 ° or less, preferably 8 ° or more and 20 ° or less than the contact angle before passing the liquid.

<20> in the absorbent article according to any one of <1> to <19>,

the contact angle of the shoulder portion of the convex portion after the liquid passage is smaller by 1 ° or more, more preferably by 5 ° or more, than the contact angle before the liquid passage.

<21> in the absorbent article of <20>,

the contact angle of the shoulder portion of the convex portion after passing the liquid is smaller by 1 ° or more and 30 ° or less, preferably smaller by 5 ° or more and 20 ° or less than the contact angle before passing the liquid.

<22> in the absorbent article according to any one of <5> to <8>,

the contact angle of the lower layer is smaller than the shoulder of the convex portion by 2 ° or more, preferably by 5 ° or more.

<23> in the absorbent article of <22>,

the contact angle of the lower layer is smaller than the shoulder of the convex portion by 2 ° or more and 70 ° or less, preferably by 5 ° or more and 50 ° or less.

<24> in the absorbent article according to any one of <1> to <23>,

the contact angle at the top before passing through the liquid is 130 ° or more and 160 ° or less, preferably 140 ° or more and 155 ° or less.

<25> in the absorbent article according to any one of <1> to <24>,

the contact angle at the top after passing through the liquid is 140 ° or more and 170 ° or less, preferably 145 ° or more and 165 ° or less, on the premise that the contact angle at the top before passing through the liquid is larger than that.

<26> in the absorbent article according to any one of <1> to <25>,

the contact angle at the shoulder before passing through the liquid is 120 ° or more and 150 ° or less, preferably 125 ° or more and 145 ° or less.

<27> in the absorbent article according to any one of <1> to <26>,

the contact angle at the shoulder after passing through the liquid is 90 ° or more and 140 ° or less, preferably 95 ° or more and 135 ° or less, on the premise that the contact angle at the shoulder before passing through the liquid is smaller.

<28> in the absorbent article according to any one of <5> to <8>, <22>, <23>,

the contact angle θ of the lower layer is 50 ° or more and 85 ° or less, preferably 55 ° or more and 80 ° or less.

< example >

The invention is further illustrated by the following examples. However, the scope of the present invention is not limited to these examples. In the following, peach leaf extract was used as a hydrophilic skin care agent, and argan oil was used as a hydrophobic skin care agent. As the raw material fiber, a core-sheath structural fiber having a core component composed of PET (polyethylene terephthalate), a sheath component composed of PE (polyethylene), a core-sheath ratio of 50 mass% to 50 mass%, and a fineness of 2.3dtex was used.

Example 1

The nonwoven fabric is obtained by nonwoven fabric-forming fibers coated with a known hydrophilic oil (fiber treating agent) and then subjecting the nonwoven fabric to uneven processing. The nonwoven fabric was a nonwoven fabric to which 0.35 mass% of a hydrophilic oil had been attached. The nonwoven fabric cut into 10cm×10cm was sprayed with 0.25g of the treatment solution, the treatment solution was spread over the nonwoven fabric, and the nonwoven fabric was left to stand for 5 hours to dry, thereby obtaining a nonwoven fabric of example 1.

The treatment liquid used in the nonwoven fabric of example 1 was a mixture of an argin-ethanol solution in which argin was dissolved at a concentration of 10 mass% in ethanol and a peach leaf extract at a mass ratio of 1:1.

In the nonwoven fabric of example 1, peach leaf extract as a hydrophilic skin care agent and argan oil as a hydrophobic skin care agent were contained as skin care agents.

The contact angle before and after passing the liquid in each of the top and shoulder of the convex portion of the nonwoven fabric of example 1 was measured by the above-described measurement method. The measurement result is shown in fig. 7 (a). In fig. 7 (a), fig. 7 (B), fig. 8 (a), and fig. 8 (B), the value of the contact angle θ/2 of the vertical axis corresponds to the value of 1/2 of the contact angle θ. The contact angle θ is θ1, θ1', θ2, or θ2' described above. In the bar charts of the respective figures, the blank bar charts indicate the contact angle θ/2 before passing the liquid, and the bar charts with hatching inside indicate the contact angle θ/2 after passing the liquid.

Example 2

The nonwoven fabric having irregularities cut into 10cm×10cm and to which 0.35 mass% of the hydrophilic oil agent was attached as in example 1 was sprayed with 1.5g of the peach leaf extract, and the nonwoven fabric was left to stand for 5 hours and dried to obtain the nonwoven fabric of example 2.

The nonwoven fabric of example 2 contains, as a skin care agent, peach leaf extract as a hydrophilic skin care agent.

The contact angle before and after passing the liquid in each of the top and shoulder portions in the convex portion of the nonwoven fabric of example 2 was measured by the above-described measurement method. The measurement results are shown in fig. 7 (B).

Comparative example 1

The nonwoven fabric having irregularities formed by cutting 10cm×10cm and to which 0.35 mass% of the hydrophilic oil agent was attached was sprayed with 0.25g of a 10 mass% concentration of an argin-ethanol solution, and the nonwoven fabric was left to stand for 5 hours and dried to obtain a nonwoven fabric of comparative example 1.

The nonwoven fabric of comparative example 1 contained argan oil as a hydrophobic skin care agent.

The contact angle before and after passing the liquid in each of the top and shoulder portions of the convex portion of the nonwoven fabric of comparative example 1 was measured by the above measurement method. The measurement results are shown in fig. 8 (a).

Comparative example 2

As the nonwoven fabric of comparative example 2, a 10cm×10cm cut nonwoven fabric having irregularities and to which 0.35 mass% of the same hydrophilic oil agent as in example 1 was attached was prepared.

The nonwoven fabric of comparative example 2 did not contain skin care agent.

The contact angle before and after passing the liquid was measured for each of the top and shoulder portions of the convex portion of the nonwoven fabric of comparative example 2 by the above measurement method. The measurement result is shown in fig. 8 (B).

[ evaluation ]

As shown in fig. 7, in the nonwoven fabrics of examples 1 and 2, the contact angle of the shoulder was smaller than the top, the contact angle of the top was larger after passing the liquid than before passing the liquid, and the contact angle of the shoulder was smaller after passing the liquid than before passing the liquid.

On the other hand, as shown in fig. 8, in the nonwoven fabrics of comparative examples 1 and 2, the contact angle of the shoulder was smaller than that of the top, but in the top and the shoulder, the contact angle was hardly changed before and after passing through the liquid.

As can be seen from this, the nonwoven fabrics of examples 1 and 2 had high top hydrophobicity and high shoulder hydrophilicity due to liquid passage, and when the nonwoven fabrics were used as the front sheet of an absorbent article, a front sheet having excellent liquid permeability and less liquid return could be formed even after long-term use. As shown in fig. 7, the nonwoven fabric of example 1 was found to have a larger contact angle as a whole and a higher liquid return suppressing effect than the nonwoven fabric of example 2.

Industrial applicability

According to the absorbent article of the present invention, the liquid permeability of the front sheet can be maintained well, and liquid return is small.

Claims

1. An absorbent article having a front sheet disposed on the skin side of a wearer and an absorber disposed on the non-skin side of the front sheet, the absorbent article characterized in that:

the front sheet comprises a nonwoven fabric layer having a structure in which a plurality of protrusions protruding toward the skin of the wearer are arranged at intervals,

the non-woven fabric layer contains a hydrophilic skin care agent and a hydrophobic skin care agent,

the nonwoven fabric layer has a skin side surface and a non-skin side surface opposite to the skin side surface,

the convex portion has a shoulder and a top portion having a smaller fiber density than the shoulder, the contact angle of the top portion with physiological saline is larger than the shoulder,

with respect to the contact angle at the top before and after liquid passage, it is larger after liquid passage than before liquid passage,

with respect to the contact angle at the shoulder before and after liquid passage, it is smaller after liquid passage than before liquid passage,

the hydrophilic skin care agent of the shoulder is present in a greater density than the top,

The hydrophobic skin care agent is present in a greater density on the skin side than on the non-skin side,

also provided with an intermediate sheet which is arranged on the non-skin side of the front sheet and is composed of hydrophilic non-woven fabrics,

the intermediate sheet has a first face on the skin side and a second face on the opposite side of the first face,

the intermediate sheet of the first face side has a lower fiber density than the second face side,

the first adhesive disposed on the first surface of the intermediate sheet has a smaller application area than the second adhesive disposed on the second surface of the intermediate sheet,

the second adhesive is disposed in plurality on the second surface at intervals, and overlaps at least a part of the shoulder of the convex portion in a plan view.

2. The absorbent article of claim 1, wherein:

the contact angle of the non-skin side is smaller than the contact angle of the skin side.

3. The absorbent article of claim 1 or 2, wherein:

4. The absorbent article of claim 3, wherein:

the upper layer and the lower layer are partially fixed,

the convex portion is formed by a portion of the upper layer that is not fixed to the lower layer.

5. The absorbent article of claim 3 or 4, wherein:

the upper layer and the lower layer contain the hydrophilic skin care agent and the hydrophobic skin care agent,

the hydrophilic skin care agent and the hydrophobic skin care agent in the upper layer are present in a greater density than the lower layer.

6. The absorbent article of any one of claims 3-5, wherein:

7. The absorbent article of any one of claims 1-6, wherein:

the hydrophilic skin care agent and the hydrophobic skin care agent are natural extract components.

8. The absorbent article of any one of claims 1-7, wherein:

the front sheet has openings between the plurality of convex portions.

9. The absorbent article of any one of claims 1-8, wherein:

the difference in contact angle between the top and the shoulder of the convex portion is 2 ° or more when expressed as the former-latter before passing through the liquid.

10. The absorbent article of claim 9, wherein:

the difference in contact angle between the top and the shoulder of the convex portion is 2 ° or more and 70 ° or less when expressed as the former-the latter before passing through the liquid.

11. The absorbent article of any one of claims 1-10, wherein:

the contact angle of the top of the convex part after liquid passing is larger than the contact angle before liquid passing by more than 2 degrees.

12. The absorbent article of claim 11, wherein:

the contact angle of the top of the convex portion after liquid passing is larger by 2 DEG or more and 40 DEG or less than the contact angle before liquid passing.

13. The absorbent article of any one of claims 1-12, wherein:

the contact angle of the shoulder of the convex portion after liquid passing is smaller by 1 ° or more than the contact angle before liquid passing.

14. The absorbent article of claim 13, wherein:

the contact angle of the shoulder of the convex portion after passing the liquid is smaller by 1 ° or more and 30 ° or less than the contact angle before passing the liquid.

15. The absorbent article of any one of claims 3-6, wherein:

The contact angle of the lower layer is smaller than the shoulder of the convex portion by more than 2 °.

16. The absorbent article of claim 15, wherein:

the contact angle of the lower layer is smaller than the shoulder of the convex portion by 2 ° or more and 70 ° or less.

17. The absorbent article of any one of claims 1-16, wherein:

the contact angle at the top before passing through the liquid is 130 ° or more and 160 ° or less.

18. The absorbent article of any one of claims 1-17, wherein:

the contact angle at the top after passing through the liquid is 140 ° or more and 170 ° or less on the premise that the contact angle at the top before passing through the liquid is larger than that at the top.

19. The absorbent article of any one of claims 1-18, wherein:

the contact angle at the shoulder before passing through the liquid is 120 ° or more and 150 ° or less.

20. The absorbent article of any one of claims 1-19, wherein:

the contact angle at the shoulder after passing the liquid is 90 ° or more and 140 ° or less on the premise that the contact angle at the shoulder before passing the liquid is smaller.

21. The absorbent article according to any one of claims 3 to 6, 15, 16, wherein:

The contact angle of the lower layer is 50 DEG or more and 85 DEG or less.