JP2016069748A - Nonwoven fabric - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a nonwoven fabric sufficiently achieving both of concealing properties and suppression of remaining liquid, allowing a user to perceive the high absorbing power.MEANS: The nonwoven fabric has at least 2 layers. The layer on one side of the nonwoven fabric has a thermally fusible fiber to which a fiber treating agent is adhered, with a length between fibers of 90 μm or less. The fiber treating agent includes: a polyorganosiloxane (A); a phosphoric ester-type anionic surfactant (B); and an alkylhydroxysulfobetaine.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a nonwoven fabric.

In recent years, non-woven fabrics with various functions have been proposed by means such as a fiber structure.
For example, Patent Document 1 describes a non-woven fabric composed of a single layer for the purpose of reducing liquid residue. In the nonwoven fabric, a technique is shown in which a heat-stretchable conjugate fiber having a hydrophilizing agent is used to partially reduce the hydrophilicity by heat treatment and to create a hydrophilicity gradient.
Patent Document 2 describes a non-woven fabric that includes two layers of a first layer and a second layer, and includes crimped fibers crimped spirally on the second layer. In the nonwoven fabric, the fiber diameter of the crimped fiber of the second layer is made thicker than that of the first layer, and the apparent density of the second layer is made higher than that of the first layer from the viewpoint of the drawability of the liquid. Yes.
Patent Document 3 describes a nonwoven fabric with specific absorption time when water droplets are dropped from two kinds of heights for the purpose of suppressing liquid return. Patent Document 4 describes a synthetic fiber treating agent used as an antistatic agent component or a lubricant component when spinning synthetic fibers.

JP 2010-168715 A JP 2005-314825 A JP 2004-256935 A JP 2005-54333 A

  Nonwoven fabrics such as those shown in Patent Documents 1 to 3 contribute to the high absorption performance of the article when applied to surface sheets such as sanitary napkins due to their liquid permeability. However, even in this case, redness such as menstrual blood absorbed by the absorbent body may be seen from the surface sheet when discarded after use. Even if there is no liquid residue on the top sheet, if the redness in the absorber can be seen through the top sheet, it can easily be confused with the dirt on the top sheet, which may give the user a false and unpleasant impression. What eliminates such a misunderstanding, and a user can use it with a good impression and can realize that it is a sanitary napkin or the like having a good absorbency is desired. Therefore, it is preferable that the redness of the absorber is hidden from the surface sheet side as much as possible.

Such redness concealment property varies depending on the inter-fiber distance (gap) of the constituent fibers of the sheet laminated on the absorber, particularly the surface sheet. This interfiber distance can be set by the number of constituent fibers, for example. The greater the number, the shorter the interfiber distance and the higher the redness concealment. However, as the inter-fiber distance is reduced, the liquid permeability of the topsheet is hindered, causing a liquid residue to increase. In this case, even if the redness in the absorber can be concealed, the redness of the remaining liquid increases without being able to pass through the top sheet, which does not lead to an improvement in the impression to the user. Moreover, the liquid which touches a skin will arise rather and it may fall to a feeling of wearing.
Thus, conventionally, it has been difficult to achieve both the suppression of the remaining liquid and the concealment of redness.

  In view of the above-described problems, the present invention relates to a nonwoven fabric that can achieve both high concealability and liquid residue suppression at a high level, and allow the user to realize that the absorbency is high.

  The present invention is a nonwoven fabric having at least two layers, and the layer on one surface side of the nonwoven fabric has a heat-fusible fiber having a fiber-to-fiber distance of 90 μm or less and a fiber treatment agent attached thereto, Provided is a nonwoven fabric in which the treating agent contains (A) a polyorganosiloxane, (B) a phosphoric ester type anionic surfactant, and (C) an alkylhydroxysulfobetaine.

  The non-woven fabric of the present invention can achieve both high concealability and liquid residue suppression at a high level.

It is sectional drawing which shows typically one preferable embodiment of the nonwoven fabric of this invention. It is a figure which expands and shows typically the state where the fiber treating agent adhered to the heat-fusible fiber. It is sectional drawing which shows the 1st layer and 2nd layer of the nonwoven fabric of FIG. (I) is a perspective view which shows another preferable embodiment of the nonwoven fabric of this invention, (ii) is a partially expanded view of sectional drawing in alignment with the thickness direction of the nonwoven fabric of (i). It is a block diagram which shows typically the manufacturing apparatus used suitably for manufacture of the nonwoven fabric of this invention.

  A preferred embodiment of the nonwoven fabric of the present invention will be described below with reference to the nonwoven fabric 10 shown in FIG. In addition, the nonwoven fabric of this invention is a laminated structure which consists of a some fiber layer, and is not limited to 2 layers of FIG. 1, Three or more layers may be sufficient. In the case of three or more layers, it is a “layer on one side” to be described later, and the second layer 2 having a fiber-to-fiber distance of 90 μm or less is not located at the center position of the thickness of the nonwoven fabric 10 but on the second side 10B side. The outermost layer is preferred. This is a configuration in which an intermediate layer is interposed between the first layer 1 and the second layer 2 and the second layer 2 having a small gap between the fibers is not provided at the center, and at the same time as the liquid concealing property, From the viewpoint of improving the liquid remaining prevention property in From the same viewpoint, even when the second layer 2 is not the outermost layer, it is preferable that the second layer 2 is closer to the second surface 10B side than the center position of the thickness of the nonwoven fabric 10.

In the present invention, the “hiding property” of a nonwoven fabric means that when the nonwoven fabric is viewed through, dirt on the other side is covered with the nonwoven fabric and is difficult to see. Typically, when the nonwoven fabric of the present invention is applied as a top sheet of an absorbent article, redness such as menstrual blood absorbed by the absorbent body is covered with the top sheet and is difficult to see.
This concealment can be indicated by, for example, brightness (L value) as one method. For the measurement, a simple spectral color difference meter NF333 manufactured by Nippon Denshoku Industries Co., Ltd. can be used. The L value is whiteness, and the higher the L value, the closer to white. Therefore, the L value shown in the present specification is a value measured when the nonwoven fabric is white or milky white. “White” means 80 or more in the L value, and “milky white” means 70 or more in the L value. The closer the L value measured for a nonwoven fabric is to the above-mentioned “white” or “milky white” L value, it indicates that dirt such as menstrual blood is not recognized from the surface of the nonwoven fabric. That is, from the nonwoven fabric of the present invention when applied as a top sheet, the redness of menstrual blood or the like adhering to the absorber is thinned, and the whiteness of the nonwoven fabric is strongly recognized, and it can be said that the concealability is high. In this case, the L value indicating the hiding property against dirt is preferably 65 or more, more preferably 70 or more, and still more preferably 80 or more from the viewpoint of allowing the user to recognize whiteness.
In addition, as the definition of the above-mentioned “concealment”, the nonwoven fabric of the present invention physically covers dirt and the like with fibers. Therefore, the nonwoven fabric of the present invention is not limited to the above-mentioned white or milky white as long as it has a concealing property by this covering, and may have various colors. Further, the color is not limited to one color, and may be multi-colored or may be provided with a design or the like.

  The nonwoven fabric 10 shown in FIG. 1 is a laminated structure composed of two layers of a first layer 1 on the first surface 10A side and a second layer 2 on the second surface 10B side. Both layers are hydrophilic. In the nonwoven fabric 10, the 2nd layer 2 by the side of the 2nd surface 10B which is one surface side sets the distance between fibers to 90 micrometers or less, and has the heat-fusible fiber to which the fiber processing agent adhered. The fiber treatment agent contains (A) a polyorganosiloxane, (B) a phosphate ester type anionic surfactant, and (C) an alkylhydroxysulfobetaine (hereinafter, the fibers used in the second layer 2). The treatment agent may be referred to as S1).

  Making the distance between the fibers of the second layer 2 90 μm or less means reducing the gap between the fibers. Thereby, the visibility from a clearance gap falls and the concealability of the nonwoven fabric 10 increases. That is, when the nonwoven fabric 10 is viewed through, dirt or the like on the other side is physically covered with the fibers of the second layer 2 and is difficult to see. In particular, when the nonwoven fabric 10 is applied as a top sheet, the redness of menstrual blood that has been transmitted through the top sheet and absorbed by the absorbent body is covered with the nonwoven fabric 10 and is difficult to see.

The fiber treatment agent S1 adheres to the surface of the heat-fusible fiber and increases the hydrophilicity of the surface of the fiber as compared with that before attaching the fiber treatment agent. Moreover, by attaching the component (A), the component (B), and the component (C) contained in the fiber treatment agent S1, the nonwoven fabric 10 increases the hydrophilicity of the second layer 2 as described later. In addition, the hydrophilicity has a gradient.
Thereby, the nonwoven fabric 10 is excellent in the liquid permeability from the 1st surface 10A side to the 2nd surface 10B side, and is excellent in a liquid remaining prevention property, when the 1st surface 10A side is made into a use surface (liquid receiving surface). That is, in the second layer 2, the distance between the fibers is small (fiber density is high), and a strong drawing force for the liquid from the first layer 1 is provided due to the high hydrophilicity and the hydrophilicity gradient in the thickness direction. As a result, the nonwoven fabric 10 has improved liquid permeability without leaving a liquid on the first surface 10A or the first layer 1. At the same time, the nonwoven fabric 10 has a high suppression effect on the liquid return from the second surface 10B side to the first surface 10A side by the inter-fiber distance.
On the other hand, the non-woven fabric 10 can be used as a non-woven fabric having high liquid diffusibility due to the high fiber density and hydrophilicity of the second layer 2 when the second surface 10B side is the use surface (liquid receiving surface).

  The heat-fusible fiber to which the fiber treatment agent S1 is attached may be present in any part of the second layer 2. Moreover, the 2nd layer 2 may be comprised only from the heat-fusible fiber to which fiber processing agent S1 adhered, or may contain another 1 type, or 2 or more types of fiber additionally. The second layer 2 is preferably composed only of such heat-fusible fibers, or is mainly composed of heat-fusible fibers.

  The nonwoven fabric 10 can be applied to various uses by taking advantage of the above characteristics. For example, the nonwoven fabric 10 can be used for a member that is laminated on an absorbent body of an absorbent article, particularly a surface sheet. When applying the nonwoven fabric 10 as a surface sheet, it is preferable to use the first surface 10A side toward the wearer's skin side and the second surface 10B side toward the absorber (not shown) side inside the article. In this case, the first surface 10A side is a liquid receiving surface that receives excretion fluid, and the second surface 10B side is a drainage surface that delivers the fluid to the absorber. The top sheet is excellent in the liquid permeability of the excretion fluid such as menstrual blood and the liquid remaining prevention property, and the concealing property can appropriately realize the high absorption performance of the article.

  In addition, the nonwoven fabric of this invention is not limited to this form. For example, you may arrange | position as a liquid diffusible intermediate sheet between the surface sheet of an absorbent article, and an absorber. Moreover, you may apply to articles other than an absorbent article. Depending on the application of the applied article, the second surface 10B side may be used as the liquid receiving surface, and the first surface side 10A may be used as the drainage layer. That is, the first surface 10A side may be used, or the second surface 10B side may be used. Which side is used is determined according to the specific use of the nonwoven fabric.

  Here, the 1st layer 1 and the 2nd layer 2 are layers distinguished by the difference in said fiber distance and a fiber processing agent, and the case where there is no clear boundary between both layers may be sufficient. When the cross section in the thickness direction of the nonwoven fabric 10 is enlarged with an electron microscope, the interface between both layers can be observed due to the difference in the distance between the fibers, and the contact angle on the fiber surface is measured by collecting the fibers. Thus, the difference between the fiber treatment agents in both layers can be determined. This distinction is similarly applied even when the nonwoven fabric has three or more layers.

As a method for producing the nonwoven fabric of the present invention as being composed of two or more layers, a method used for this type of article can be employed without any particular limitation. For example, as will be described later, the fiber webs forming each layer (before the fiber intersection is fused, that is, before the nonwoven fabric is laminated) and heat-treated, the fibers in each layer and the fibers in the adjacent layers There is a method of fusing together to integrate them. Alternatively, there is a method in which the fiber webs of each layer are separately made into a non-woven fabric and laminated, and then integrated by thermal fusion using embossing or bonding using an adhesive. From the viewpoint of making the nonwoven fabric excellent in liquid permeability without remaining liquid, a method of integrating fiber webs by heat fusion is preferable.
In particular, an air-through nonwoven fabric is preferable from the viewpoint of touch and liquid permeability. The “air-through nonwoven fabric” as used herein refers to a nonwoven fabric produced through a process of spraying a fluid of 50 ° C. or higher, for example, gas or water vapor, onto the web or the nonwoven fabric. This means not only non-woven fabrics produced only in this step, but also non-woven fabrics produced by adding this step to non-woven fabrics produced by other methods or non-woven fabrics produced by performing some steps after this step. Moreover, the nonwoven fabric of this invention is not restricted to what consists only of an air through nonwoven fabric, The thing which compounded fiber sheets and film materials, such as an air through nonwoven fabric and another nonwoven fabric, is included.

  Next, the second layer 2 and the first layer 1 will be described in detail.

(Distance between fibers of the second layer 2)
In the second layer 2, the distance between the constituent fibers is set to 90 μm or less from the viewpoint of liquid concealment. Further, from the same viewpoint, the inter-fiber distance of the second layer 2 is more preferably 80 μm or less, and further preferably 70 μm or less. This is a distance between fibers that is considerably shorter than that of a conventional nonwoven fabric, which is usually about 140 μm because of liquid permeability. For example, when the redness of menstrual blood absorbed by the absorbent body is measured through a surface sheet having an interfiber distance of about 140 μm, which is the conventional technical range, the L value is about 60, and the user feels white. Is difficult. However, when a non-woven fabric having a fiber-to-fiber distance reduced to 90 μm or less is used as the top sheet, the L value increases to 75 or more, and the redness of menstrual blood that has passed through the top sheet and is absorbed by the absorbent body is covered with the non-woven fabric. It is hidden and it becomes possible to realize the high absorbency.
In addition, the said "component fiber" means a heat-fusible fiber, when the 2nd layer 2 is comprised only from the above-mentioned heat-fusible fiber. When the second layer 2 is composed of a mixture of the heat-fusible fiber and one or more other fibers, all of the heat-fusible fiber and the other one or two or more fibers are used. Means fiber. The “constituent fibers” described below have the same meaning.

  The above-mentioned interfiber distance can be obtained by making the constituent fibers thinner and increasing the number. That is, the distance between fibers can be shortened by increasing the fiber density using thin fibers. In this case, the second layer 2 preferably contains fibers of 2.0 dtex or less as a main component, more preferably contains fibers of 1.8 dtex or less as a main component, and fibers of 1.5 dtex or less as a main component. It is further preferable to include it. This is fine compared with the conventional non-woven fabric having a fineness of about 2.2 dtex because of its liquid permeability. Thereby, the space | gap (fiber distance) between the fibers of the 2nd layer 2 becomes small, and the concealment property of the nonwoven fabric 10 is improved.

  The distance between the fibers is preferably 50 μm or more, more preferably 55 μm or more, and still more preferably 60 μm or more from the viewpoint of maintaining the liquid permeability of the nonwoven fabric 10. In this case, the fineness is preferably 0.8 dtex or more, more preferably 1.0 dtex or more, and further preferably 1.2 dtex.

As described above, when the fiber diameter is reduced in order to reduce the interfiber distance, the fiber density of the second layer 2 is increased, but the soft and soft texture of the entire nonwoven fabric 10 is maintained by the fineness of the fibers.
And the nonwoven fabric 10 formed in this way has high concealment property of a liquid. Thereby, even after the nonwoven fabric 10 has permeated menstrual blood or the like, an impression that it is clean can be given. Moreover, when the nonwoven fabric 10 is incorporated in an absorbent article, the high absorbent performance of the article can be appropriately felt.

(Measurement method of distance between fibers)
The inter-fiber distance is obtained by measuring the thickness of the nonwoven fabric to be measured as follows and applying it to Equation (1).
First, the nonwoven fabric to be measured is cut into a longitudinal direction of 50 mm and a width direction of 50 mm to produce a cut piece of the nonwoven fabric. This cut piece is placed on the napkin absorbent body, and a sanitary napkin using a nonwoven fabric to be measured as a surface sheet is prepared.
The thickness of the nonwoven fabric is measured under a pressure of 49 Pa under the state of being placed on the napkin absorber. The measurement environment is a temperature of 20 ± 2 ° C., the relative humidity is 65 ± 5%, and the measurement instrument is a microscope (manufactured by Keyence Corporation, VHX-1000). First, an enlarged photograph of the nonwoven fabric cross section is obtained. In the magnified picture, a photograph of a known size is taken at the same time. A scale is matched with the enlarged photograph of the cross section of the nonwoven fabric, and the thickness of the nonwoven fabric is measured. The above operation is performed three times, and the average value of the three times is defined as the thickness [mm] of the dried nonwoven fabric. In the case of a laminated product, the boundary is determined from the fiber diameter, and the thickness is calculated.
Next, the inter-fiber distance of the fibers constituting the nonwoven fabric to be measured is determined by the following formula based on Wrotnowski's assumption. An expression based on the assumption of Wrotnowski is generally used when determining the inter-fiber distance of the fibers constituting the nonwoven fabric. According to a formula based on the assumption of Wrotnowski, the interfiber distance A (μm) is the thickness h (mm) of the nonwoven fabric, the basis weight e (g / m ² ), the fiber diameter d (μm) of the fibers constituting the nonwoven fabric, It is calculated | required by the following formula | equation (1) by fiber density (rho) (g / cm < ³ >).
In addition, fiber diameter d (micrometer) measures 10 fiber cross sections of the cut fiber using a scanning electron microscope (Seiko Instruments Co., Ltd. DSC6200), and makes the average value the fiber diameter.
The fiber density ρ (g / cm ³ ) is measured using a density gradient tube in accordance with the measurement method of the density gradient tube method described in the JIS L1015 chemical fiber staple test method (URL is http: // kikakuui. com / l / L1015-2010-01.html, JIS Handbook Fiber-2000 for books, described in P.764-765 of (Japan Standards Association).
The basis weight e (g / m ² ) is cut to a predetermined size (0.12 m × 0.06 m or the like), and after weight measurement, the basis weight is calculated by the following formula.
Weight / area determined from the predetermined size = basis weight (g / m ² )

(Method for measuring fineness of constituent fibers)
The cross-sectional shape of the fiber is measured with an electron microscope, etc., and the cross-sectional area of the fiber (the cross-sectional area of each resin component in a fiber formed of a plurality of resins) is measured, and the resin is measured with a DSC (differential thermal analyzer). Is specified (in the case of multiple resins, the approximate component ratio is also), the specific gravity is determined, and the fineness is calculated.
For example, in the case of short fibers composed only of PET, the cross section is first observed and the cross sectional area is calculated. Then, by measuring with DSC, it is comprised from single component resin from melting | fusing point and peak shape, and it identifies that it is a PET core. Thereafter, the fineness is calculated by calculating the weight of the fiber using the density and the cross-sectional area of the PET resin.

When measuring the distance between the fibers and the fineness of the constituent fibers, if the nonwoven fabric to be measured is a member (for example, a surface sheet) incorporated in an absorbent article such as a sanitary product or a disposable diaper, take it out as follows. Measure. That is, in the absorbent article, after the adhesive used for joining the member to be measured and another member is weakened by a cooling means such as cold spray, the member to be measured is peeled off and taken out.
In addition, this taking-out method is applied in the measurement which concerns on the nonwoven fabric of this invention, such as the measurement of the adhesion amount (content) of a fiber processing agent mentioned later.

<Fiber treatment agent S1 used for the second layer 2>
In addition, the second layer 2 is heat-sealed with (A) a polyorganosiloxane, (B) a phosphoric ester-type anionic surfactant, and (C) a fiber treatment agent S1 containing an alkylhydroxysulfobetaine. Has sexual fibers. Thereby, the second layer 2 has high hydrophilicity. Further, as will be described later, the hydrophilicity has a gradient by heat treatment.

The component (C) can be closely adsorbed to the heat-fusible fiber having a small fiber diameter, and can impart high hydrophilicity to the fiber. Usually, as shown in FIG. 2, the fiber treatment agent adhering to the fiber exists as a thin film 83 having a thickness of about 5 nm to 10 nm on the fiber surface (about 0.4 mass% with respect to the mass of the fiber). However, this thin film tends to become thinner as the fineness of the fiber is reduced. As a result, the treatment with the conventional fiber treatment agent is weakly hydrophilic and has a high hydrophobicity.
On the other hand, since component (C) has both an anionic group and a cationic group, when adsorbing to the fiber surface, electrostatic repulsion between components (C) is suppressed and a relatively dense state. Become. Furthermore, since the component (C) has a hydroxy group between the anionic group and the cationic group, the component (C) has a hydrogen bonding action and is more easily attracted to the component (C). As a result, component (C) can be adsorbed densely and imparted a high degree of hydrophilicity even with a small addition amount (thin film thickness) with respect to a heat-fusible fiber having a small fiber diameter.
In addition, FIG. 2 has shown the thing of the core-sheath structure (core 81, sheath 82) as an example of a heat-fusible fiber. However, the heat-fusible fiber used in the present invention is not limited to this.

Moreover, in the nonwoven fabric 10, the 2nd layer 2 which has the heat-fusible fiber to which the fiber processing agent S1 containing the said three components adhered can give a gradient in hydrophilicity by performing heat treatment.
That is, since the polyorganosiloxane as the component (A) promotes the penetration of the alkylhydroxysulfobetaine as the component (C) into the fiber, the hydrophilicity of the fiber surface changes to a low value by heat treatment. This is because the polysiloxane chain of the polyorganosiloxane and the alkyl chain of the alkylhydroxysulfobetaine are incompatible with each other, so the alkylhydroxysulfobetaine is heated inside the hydrophobic heat-fusible fiber that is more familiar. It is thought to occur because it penetrates when melted. Thereby, for example, in the process of blowing hot air to the web, which is one process of the manufacturing process described later, the value of the contact angle of the fiber changes according to the amount of heat as follows. That is, the amount of heat received by the fibers in the web is naturally different between the hot air blowing surface and the opposite surface (net surface). As a result, the amount of heat received is different between the fiber on the hot air blowing surface and the fiber on the opposite side, and the fiber on the hot air blowing surface has a lower hydrophilicity and a contact angle value than the fiber on the opposite side. It will be expensive. By utilizing this fact, it is possible to provide a hydrophilicity gradient in which the hydrophilicity increases from the first surface 2A side to the second surface 2B side of the second layer 2.

Unless otherwise specified, the above gradient means a state in which the hydrophilicity on the second surface 2B side is higher than the first surface 2A side in the thickness direction of the second layer 2. This “gradient” widely includes various modes having a difference in hydrophilicity between the first surface 2A side and the second surface 2B side in the second layer 2, and may be a mode of gradually increasing, The aspect which becomes high in steps may be sufficient (henceforth, the hydrophilicity gradient of the 1st layer 1 and the hydrophilicity gradient of the nonwoven fabric 10 whole from the 1st layer 1 to the 2nd layer 2 are the same meaning).
Further, instead of the above-described gradient mode, the hydrophilicity is reversed on the first surface 2A side and the second surface 2A side (the hydrophilicity on the second surface 2A side is higher than that on the first surface 2A side). (Low) aspect may be sufficient.
The “first surface 2A” in the second layer 2 is a surface located on the first surface 10A side of the nonwoven fabric 10 as shown in FIG. Moreover, the “second surface 2B” in the second layer 2 is a surface located on the second surface 10B side of the nonwoven fabric 10 as shown in FIG.

  The adhesion amount (content) of the fiber treatment agent S1 containing the component (A), the component (B) and the component (C) to the heat-fusible fiber is the total amount of the heat-fusible fiber excluding the fiber treatment agent. As a ratio with respect to mass, from a viewpoint of improving hydrophilicity, 0.1 mass% or more is preferable, 0.2 mass% or more is more preferable, and 0.3 mass% or more is further more preferable. Further, the upper limit is preferably 1.5% by mass or less, more preferably 1.0% by mass or less, and further preferably 0.5% by mass or less from the viewpoint of suppressing the contamination of the nonwoven fabric processing machine. For example, the adhesion amount of the fiber treatment agent S1 to the heat-fusible fiber is preferably 0.1% by mass or more and 1.5% by mass or less as a ratio to the total mass of the heat-fusible fiber excluding the fiber treatment agent, 0.2 mass% or more and 1.0 mass% or less are more preferable, and 0.3 mass% or more and 0.5 mass% or less are more preferable.

In addition, when analyzing the adhering fiber treatment agent in the nonwoven fabric to which the fiber treatment agent is adhered according to the present invention, it is preferable to analyze according to the following procedure. First, the nonwoven fabric to be analyzed is washed with a suitable solvent. Examples of the cleaning solvent include a mixed solvent of ethanol and methanol and a mixed solvent of ethanol and water. Next, the solvent used for washing the non-woven fabric to be analyzed (cleaning solvent containing the fiber treatment agent) is dried, and the residue is quantified so that the total amount of the fiber treatment agent adhering to the non-woven fabric is obtained. It can be measured. In addition, after selecting an appropriate column and solvent according to the composition of the residue, each component is fractionated by high performance liquid chromatography, and each fraction is further subjected to MS measurement, NMR measurement, elemental analysis, etc. By performing the above, the structure of each fraction can be identified. When the fiber treatment agent contains a polymer compound, it becomes easier to identify the constituent components by using a technique such as gel permeation chromatography (GPC) together.
Said analysis method is similarly used also with respect to each component in fiber processing agent S1 mentioned later, fiber processing agents S2-S5 used for the 1st layer 1, and each component.

Hereinafter, each component will be described.
(Ingredient (A))
As the polyorganosiloxane, any one of a linear one and a crosslinked two-dimensional or three-dimensional network structure can be used. Preferably it is substantially linear. The term “substantially” as used herein may include a polyorganosiloxane having a branched structure by modifying a part of the polyorganosiloxane skeleton or by making a part of the alkyl group a long chain. It means that the content of the polyorganosiloxane is 5% or less.

Specific examples of suitable polyorganosiloxanes are alkylalkoxysilanes, arylalkoxysilanes, alkylhalosiloxane polymers, and cyclic siloxanes. The alkoxy group is typically a methoxy group. As the alkyl group, an alkyl group which may have a side chain having 1 to 18 carbon atoms, preferably 1 to 8 carbon atoms, particularly 1 to 4 carbon atoms is suitable. Examples of the aryl group include a phenyl group, an alkylphenyl group, and an alkoxyphenyl group. Instead of an alkyl group or an aryl group, a cyclic hydrocarbon group such as a cyclohexyl group or a cyclopentyl group, or an aralkyl group such as a benzyl group may be used.
Further, the polyorganosiloxane referred to in the present invention further promotes the penetration of the component (C), and from the viewpoint of increasing the contact angle of the fiber surface from the state where the component (C) is adhered by heating, the highly hydrophilic POE This is a concept that does not include a chain-modified polyorganosiloxane.

  The most typical polyorganosiloxanes preferred in the present invention include polydimethylsiloxane, polydiethylsiloxane, polydipropylsiloxane and the like. Of these, polydimethylsiloxane is particularly preferred.

  The molecular weight of the polyorganosiloxane is preferably a high molecular weight. Specifically, the weight average molecular weight is preferably 100,000 or more, more preferably 150,000 or more, and further preferably 200,000 or more. The upper limit is preferably 1,000,000 or less, more preferably 800,000 or less, and still more preferably 600,000 or less. Two or more types of polyorganosiloxanes having different molecular weights may be used as the polyorganosiloxane. When two or more types of polyorganosiloxanes having different molecular weights are used, one of them has a mass average molecular weight of preferably 100,000 or more, more preferably 150,000 or more, and still more preferably 200,000 or more. The upper limit is preferably 1,000,000 or less, more preferably 800,000 or less, and still more preferably 600,000 or less. Another type has a mass average molecular weight of preferably less than 100,000, more preferably 50,000 or less, more preferably 35,000 or less, and particularly preferably 20,000 or less. The lower limit is preferably 2000 or more, more preferably 3000 or more, and still more preferably 5000 or more. Further, the preferred blending ratio of the polyorganosiloxane having a weight average molecular weight of 100,000 or more and the polyorganosiloxane having a weight average molecular weight of less than 100,000 is a mass ratio, preferably 1:10 to 4: 1, more preferably 1. : 5 to 2: 1.

The mass average molecular weight of the polyorganosiloxane is measured using GPC (manufactured by Tosoh Corporation, trade name CCPD). The measurement conditions are as follows. The calculated molecular weight is calculated with polystyrene.
Separation column: GMHHR-H + GMHHR-H (cation)
Eluent: L Farmin DM20 / CHCl ₃
Solvent flow rate: 1.0 ml / min
Separation column temperature: 40 ° C

  As the component (A), any one of the above-mentioned agents can be used alone or in admixture of two or more.

  The content of the polyorganosiloxane in the fiber treatment agent S1 attached to the heat-sealing fibers of the second layer 2 is preferably 1% by mass or more from the viewpoint of increasing the change in hydrophilicity due to heat treatment. More preferably, it is at least mass%. Moreover, 30 mass% or less is preferable from a viewpoint of making it easy to absorb the liquid from the 1st layer 1, and 20 mass% or less is still more preferable. For example, the content of the polyorganosiloxane in the fiber treatment agent S1 attached to the constituent fibers of the second layer 2 is preferably 1% by mass to 30% by mass, and preferably 5% by mass to 20% by mass. More preferably it is.

  Furthermore, when the nonwoven fabric 10 is applied to the absorbent article as a surface sheet, the waste fluid adheres to the skin from the viewpoint of preventing the hydrophilicity of the second layer 2 from being excessively reduced, that is, the liquid residue in the nonwoven fabric 10. Also from the viewpoint of preventing the amount from increasing, the content of the polyorganosiloxane in the fiber treatment agent S1 is preferably within the above range.

  A commercial item can also be used as polyorganosiloxane as a component (A). For example, “KF-96H-1 million Cs” manufactured by Shin-Etsu Silicone Co., “SH200 Fluid 1000000 Cs” manufactured by Toray Dow Corning Co., Ltd. and those containing two types of polyorganosiloxane include “ KM-903 "or" BY22-060 "manufactured by Toray Dow Corning Co. can be used.

In addition, unless otherwise explained, the “fiber treatment agent” used as a reference for the content of the component of the fiber treatment agent such as the component (A), the component (B) and the component (C) described later is “attached to the nonwoven fabric”. It is not a fiber treatment agent before being attached to the nonwoven fabric. When the fiber treatment agent is attached to the nonwoven fabric, since the fiber treatment agent is usually diluted with a suitable solvent such as water, the content of the component of the fiber treatment agent, for example, in the fiber treatment agent of component (A) The content of can be based on the total mass of the diluted fiber treatment agent.
The above analysis method is similarly applied to fiber treatment agents S2 to S5 used for the first layer 1 described later.

(Ingredient (B))
The phosphoric acid ester type anionic surfactant as component (B) improves properties such as carding ability of the raw cotton and uniformity of the web, thereby preventing an increase in the productivity of the nonwoven fabric and a reduction in quality. For this purpose, it is added to the fiber treatment agent S1. Specific examples include alkyl ether phosphates, dialkyl phosphates, and alkyl phosphates. Of these, alkyl phosphates are preferred from the viewpoint of processability.

  Various alkyl ether phosphates can be used without particular limitation. For example, those having saturated carbon chains such as stearyl ether phosphate, myristyl ether phosphate, lauryl ether phosphate, palmityl ether phosphate, oleyl ether phosphate, palmitoleyl ether phosphate, etc. Unsaturated carbon chains and those having side chains in these carbon chains. More preferably, it is a completely neutralized or partially neutralized salt of a mono- or dialkyl phosphate ester having a carbon chain of 16 or more and 18 or less. Examples of the salt of alkyl ether phosphate include alkali metals such as sodium and potassium, ammonia, and various amines. Alkyl phosphate ester can be used individually by 1 type or in mixture of 2 or more types.

  Specific examples of the alkyl phosphate ester include those having a saturated carbon chain such as stearyl phosphate ester, myristyl phosphate ester, lauryl phosphate ester, palmityl phosphate ester, oleyl phosphate ester, palmitoleyl phosphate ester, etc. Examples include unsaturated carbon chains and those having side chains in these carbon chains. More preferably, it is a completely neutralized or partially neutralized salt of a mono- or dialkyl phosphate ester having a carbon chain of 16 or more and 18 or less. Examples of the alkyl phosphate ester salt include alkali metals such as sodium and potassium, ammonia, and various amines. Alkyl phosphate ester can be used individually by 1 type or in mixture of 2 or more types.

  The content ratio of the component (B) in the fiber treatment agent S1 attached to the heat-sealing fibers of the second layer 2 is preferably 5% by mass or more from the viewpoint of card machine passability and web uniformity, More preferably, it is 10 mass% or more. Further, from the viewpoint of not preventing the fiber from being hydrophobized by polyorganosiloxane due to heat treatment, the content is preferably 30% by mass or less, more preferably 25% by mass or less.

(Ingredient (C))
The component (C), alkylhydroxysulfobetaine, has the property of adsorbing closely to the fiber surface as described above. For this reason, the component (C) can realize high hydrophilicity, which is difficult to obtain with a normal fiber treatment agent, for fibers having a reduced fiber diameter.
Specifically, alkylhydroxysulfobetaine is a surfactant represented by the following general formula (I).

In the formula, R ¹ represents an alkyl group having 6 to 24 carbon atoms. Among these, in addition to the dense adsorption of sulfobetaine groups, the number of carbon atoms is more preferably 8 or more, from the viewpoint of forming a denser adsorption surface on the fiber surface by hydrophobic interaction with hydrocarbon groups. Is more preferable, 22 or less is more preferable, and 18 or less is more preferable.

  More specifically, lauryl hydroxysulfobetaine, myristyl hydroxysulfobetaine, palmityl hydroxysulfobetaine, and stearyl hydroxysulfobetaine can be used.

  As the component (C), any one of the above-mentioned agents can be used alone or in admixture of two or more.

  The content ratio of the component (C) in the fiber treatment agent S1 attached to the heat-sealing fiber of the second layer 2 is preferably less than 10% by mass, more preferably less than 9% by mass, and still more preferably. Is less than 8% by weight. Thereby, the hydrophilicity gradient by the said component (A) is easy to be formed more clearly, and the low liquid remaining property and low liquid return property of a nonwoven fabric can be maintained. The lower limit is preferably 3% by mass or more, more preferably 5% by mass or more, from the viewpoint of imparting sufficient hydrophilicity to the fiber.

  The content ratio of the polyorganosiloxane of the component (A) and the alkylhydroxysulfobetaine of the component (C) in the fiber treatment agent S1 attached to the heat-fusible fiber of the second layer 2 is a mass ratio, The ratio is preferably 1: 1.6 to 1: 0.6, more preferably 1: 1.3 to 1: 0.9. In the fiber treatment agent S1, the content ratio of the polyorganosiloxane of component (A) and the phosphate ester type anionic surfactant of component (B) is a mass ratio, preferably from 1: 5. 10: 1, more preferably 1: 2 to 3: 1.

  The fiber treatment agent S1 attached to the heat-fusible fiber of the second layer 2 may contain other components in addition to the components (A), (B), and (C) described above. As other components, anionic, cationic, zwitterionic and nonionic surfactants can be used.

  Examples of anionic surfactants include alkyl phosphate sodium salt, alkyl ether phosphate sodium salt, dialkyl phosphate sodium salt, dialkyl sulfosuccinate sodium salt, alkylbenzene sulfonate sodium salt, alkyl sulfonate sodium salt, alkyl sulfate sodium salt, secondary Examples include alkyl sulfate sodium salt (all alkyls preferably have 6 to 22 carbon atoms, particularly preferably 8 to 22 carbon atoms). These may use other alkali metal salts such as potassium salts in place of sodium salts.

  Examples of the cationic surfactant include alkyl (or alkenyl) trimethyl ammonium halide, dialkyl (or alkenyl) dimethyl ammonium halide, alkyl (or alkenyl) pyridinium halide, and these compounds have 6 or more carbon atoms. Those having 18 or less alkyl groups or alkenyl groups are preferred. Examples of the halogen in the halide compound include chlorine and bromine.

  Examples of zwitterionic surfactants include alkylbetaines. Among alkylbetaines, alkyl (C1 to 30) dimethylbetaine, alkyl (C1 to 30) amide alkyl (C1 to 4) dimethylbetaine, alkyl (C1 to 30) dihydroxyalkyl (C1-C30) Betaine-type amphoteric surfactant such as betaine, sulfobetaine-type amphoteric surfactant, alanine type [alkyl (C1-C30) aminopropionic acid type, alkyl (carbon number) 1 to 30) iminodipropionic acid type, etc.] amphoteric surfactants, glycine types such as alkylbetaines [alkyl (carbon number of 1 to 30) aminoacetic acid type, etc.] amino acid type amphoteric surfactants such as amphoteric surfactants Aminosulfonic acid type amphoteric surfactants such as alkyl (1 to 30 carbon atoms) taurine type It is below. Among them, alkyl (1 to 30 carbon atoms) dimethyl betaine is preferable, and alkyl dimethyl betaine having 16 to 22 carbon atoms (for example, stearyl) is particularly preferable.

  Examples of nonionic surfactants include polyalcohol fatty acid esters such as glycerin fatty acid ester, poly (preferably n = 2 to 10) glycerin fatty acid ester, sorbitan fatty acid ester (all preferably 8 carbon atoms of fatty acid). 60 or less), polyoxyalkylene (addition mole number 2 or more and 20 or less) alkyl (carbon number 8 or more and 22 or less) amide, polyoxyalkylene (addition mole number 2 or more and 20 or less) alkyl (carbon number 8 or more and 22 or less) ether , Polyoxyalkylene-modified silicone, amino-modified silicone and the like. Of these, glycerin fatty acid ester is preferable, and glycerin monocaprylate is more preferable.

  A treatment agent such as an anti-sticking agent such as modified silicone may be added to the fiber treatment agent S1 used for the second layer 2.

(Fiber treated with fiber treatment agent)
The heat-fusible fiber constituting the second layer 2 is treated with a fiber treatment agent, and the fiber treatment agent adheres to at least the surface. As the heat-fusible fiber before adhering, the fiber used for the nonwoven fabric can be used without particular limitation. For example, a heat-fusible core-sheath composite fiber, a non-heat-stretchable fiber, a heat-shrinkable fiber, a three-dimensional crimped fiber, a latent crimped fiber, a hollow fiber, and the like can be given. In the present invention, it is preferable to use a heat-fusible core-sheath composite fiber.
The heat-fusible core-sheath type composite fiber subjected to the fiber treatment is a heat-sealable and core-sheath type composite fiber similar to the heat-fusible core-sheath type composite fiber before attaching the fiber treatment agent. is there. The core-sheath type composite fiber may be a concentric core-sheath type, an eccentric core-sheath type, a side-by-side type, or an irregular shape, and is preferably a concentric core-sheath type.

As the heat-fusible fiber to which the fiber treatment agent is attached, various fibers that do not inhibit the penetration of the components in the fiber treatment agent S1 into the fiber can be used. For example, “core-sheath type composite fiber having a sheath part containing polyethylene resin and a core part made of a resin component having a melting point higher than that of the polyethylene resin (hereinafter referred to as“ core-sheath type composite fiber ”) Fiber P) ”. Examples of the polyethylene resin constituting the sheath of the core-sheath type composite fiber P include low density polyethylene (LDPE), high density polyethylene (HDPE), linear low density polyethylene (LLDPE), and the density is 0.935 g. It is preferably a high-density polyethylene that is not less than / cm ^{3 and not} more than 0.965 g / cm ³ . The resin component constituting the sheath portion of the core-sheath type composite fiber P is preferably a polyethylene resin alone. However, the present invention is not limited to this, and a blend of polyethylene resin and another resin may be used. Other resins to be blended include polypropylene resin, ethylene-vinyl acetate copolymer (EVA), ethylene-vinyl alcohol copolymer (EVOH), and the like. However, as for the resin component which comprises a sheath part, it is preferable that 50 mass% or more in the resin component of a sheath part is especially 70 mass% or more and 100 mass% or less is a polyethylene resin. Further, the polyethylene resin constituting the sheath part of the core-sheath type composite fiber P preferably has a crystallite size of 10 nm or more and 20 nm or less, and more preferably 11.5 nm or more and 18 nm or less.

The sheath part of the core-sheath type composite fiber P plays a role of providing the heat-fusible core-sheath type composite fiber with heat-fusibility and taking in the fiber treatment agent S1 described above during heat treatment. Thereby, the penetration | invasion to the fiber inside of the component in fiber treatment agent S1 mentioned above is accelerated | stimulated, and the hydrophilization gradient in the nonwoven fabric 10 becomes still easier to be formed. However, the heat-fusible fiber used in the present invention is not limited to the core-sheath type composite fiber P. For example, the sheath may be polypropylene (PP) or copolymer polyester depending on the resin component of the core.
On the other hand, a core part is a part which provides intensity | strength to a heat-fusible core-sheath-type composite fiber. As the resin component constituting the core part of the core-sheath type composite fiber P, a resin component having a melting point higher than that of the polyethylene resin that is the constituent resin of the sheath part can be used without particular limitation. Examples of the resin component constituting the core include polyolefin resins such as polypropylene (PP) (excluding polyethylene resin), polyester resins such as polyethylene terephthalate (PET), and polybutylene terephthalate (PBT). Furthermore, a polyamide-type polymer, the copolymer of 2 or more types of the resin component mentioned above, etc. can be used. A plurality of types of resins can be blended and used. In this case, the melting point of the core is the melting point of the resin having the highest melting point.
The heat-fusible core-sheath composite fiber to which the fiber treatment agent is attached has a difference in melting point between the resin component constituting the core part and the resin component constituting the sheath part (the former-the latter) at 20 ° C. or higher. It is preferable that the non-woven fabric is easily produced, and is preferably 150 ° C. or lower. The melting point when the resin component constituting the core is a blend of a plurality of types of resins is the melting point of the resin having the highest melting point.

  The heat-fusible fiber to which the fiber treatment agent is attached is preferably a fiber whose length is increased by heating (hereinafter also referred to as heat-extensible fiber). Examples of the heat-extensible fiber include a fiber that spontaneously extends as the crystal state of the resin changes due to heating. The heat-extensible fiber is present in the nonwoven fabric in a state where its length is extended by heating, a state where it can be extended by heating, or both. When heat-extensible fibers are heated, the fiber treatment agent on the surface is easily taken into the interior, and it becomes easy to form a plurality of portions having greatly different hydrophilicity by heat treatment in the fibers and the nonwoven fabric produced using the fibers.

A preferable heat-extensible fiber is a composite fiber (hereinafter also referred to as a heat-extensible composite fiber) having a first resin component that constitutes a core part and a second resin component that constitutes a sheath part. The second resin component has a lower melting point or softening point than the first resin component, and at least part of the fiber surface is continuously present in the length direction. A 1st resin component is a component which expresses the heat | fever extensibility of this fiber, and a 2nd resin component is a component which expresses heat-fusibility.
The melting points of the first resin component and the second resin component are defined as temperatures measured by the following method using a differential scanning calorimeter (DSC6200 manufactured by Seiko Instruments Inc.). That is, a thermal analysis of a finely cut fiber sample (sample weight 2 mg) is performed at a temperature rising rate of 10 ° C./min, and the melting peak temperature of each resin is measured and defined by the melting peak temperature. When the melting point of the second resin component cannot be clearly measured by this method, the resin is defined as “resin having no melting point”. In this case, the temperature at which the second resin component is fused to such an extent that the strength of the fusion point of the fiber can be measured is used as the temperature at which the molecular flow of the second resin component begins, and this is used instead of the melting point.

  The preferred orientation index of the first resin component in the heat-extensible conjugate fiber is naturally different depending on the resin used. For example, in the case of a polypropylene resin, the orientation index is preferably 60% or less, more preferably 40% or less, and still more preferably 25% or less. When the first resin component is polyester, the orientation index is preferably 25% or less, more preferably 20% or less, and still more preferably 10% or less. On the other hand, the second resin component preferably has an orientation index of 5% or more, more preferably 15% or more, and still more preferably 30% or more. The orientation index is an index of the degree of orientation of the polymer chain of the resin constituting the fiber. And when the orientation index of a 1st resin component and a 2nd resin component is each said value, a heat | fever extensible composite fiber comes to expand | extend by heating.

  The orientation index of the first resin component and the second resin component is determined by the method described in paragraphs [0027] to [0029] of JP2010-168715A. Moreover, the method in which each resin component in the thermally stretchable conjugate fiber achieves the orientation index as described above is described in paragraphs [0033] to [0036] of JP-A No. 2010-168715.

  The heat stretchable conjugate fiber can be stretched by heat at a temperature lower than the melting point of the first resin component. The heat-extensible conjugate fiber preferably has a thermal elongation rate of 0.5% or more and 20% or less at a temperature 10 ° C. higher than the melting point of the second resin component (softening point in the case of a resin having no melting point). More preferably, it is 3% or more and 20% or less, and further preferably 5.0% or more and 20% or less. A nonwoven fabric containing fibers having such a thermal elongation rate becomes bulky due to the elongation of the fibers or has a three-dimensional appearance. The thermal elongation rate of the fiber is determined by the method described in paragraphs [0031] to [0032] of JP2010-168715A.

  The specific mass ratio between the first resin component and the second resin component in the heat-extensible composite fiber is 10:90 to 90:10, particularly 20:80 to 80:20, especially 50:50 to 70: in mass ratio. 30 is preferable. As the fiber length of the heat-extensible conjugate fiber, one having an appropriate length is used according to the method for producing the nonwoven fabric. For example, when the nonwoven fabric is manufactured by the card method as described later, the fiber length is preferably about 30 mm to 70 mm.

  The fiber diameter of the heat-extensible composite fiber is appropriately selected according to the specific use of the nonwoven fabric. When the nonwoven fabric is used as a constituent member of an absorbent article such as a surface sheet of the absorbent article, it is preferable to use a nonwoven fabric having a size of 10 μm to 35 μm, particularly 15 μm to 30 μm. In addition, the fiber diameter of the heat-extensible composite fiber is reduced when the fiber diameter is reduced, and the fiber diameter is a fiber diameter when the nonwoven fabric is actually used.

  As the heat-extensible composite fiber, in addition to the above-described heat-extensible composite fiber, Japanese Patent No. 4131852, Japanese Patent Application Laid-Open No. 2005-350836, Japanese Patent Application Laid-Open No. 2007-303035, Japanese Patent Application Laid-Open No. 2007-204899, The fibers described in JP 2007-204901 A and JP 2007-204902 A can also be used.

The heat-fusible fiber may contain titanium oxide.
Titanium oxide preferably has a particle size in the range of, for example, 0.1 μm or more and 2 μm or less, and can be spun by containing it in a resin in the fiber spinning step.
By using fibers containing titanium oxide, the nonwoven fabric has increased whiteness and concealment. In particular, an absorbent article using a nonwoven fabric containing a fiber containing titanium oxide as a surface material and the like has high concealability of body fluids such as menstrual blood and urine absorbed in the absorbent body, and the visual appearance from the appearance after use A dry feeling can be obtained.
Titanium oxide can be added in any content. From the viewpoint of enhancing the concealability, the amount of titanium oxide contained in the heat-fusible fiber is preferably 0.5% by mass or more, more preferably 1% by mass or more with respect to the total mass of the fiber. Moreover, from the viewpoint of productivity, fiber-stretch properties, card process properties in the nonwoven fabric manufacturing process, and cut properties in the post-processing process, it is preferably 5% by mass or less, more preferably 4.5% by mass or less.

  The above-described heat-extensible fibers can be thermally stretched at the time of hot air treatment described later to widen the gaps between the fibers and form a bulky fiber layer. Moreover, a heat | fever extensible fiber reduces the hydrophilicity by a fiber processing agent in the part which a hot air hits. Considering this characteristic, it is preferable that the heat-extensible fiber is present as a constituent fiber of the first layer 1 on the first surface 10A side. On the other hand, it is preferable that the second layer 2 does not contain the heat-extensible fiber. Even if the heat-extensible fibers are included, it is preferably 50% by mass or less based on the total mass of the constituent fibers of the second layer 2, and the heat-extensible fibers are unevenly distributed on the first surface 2A side of the second layer 2. It is preferable to do. Thereby, the nonwoven fabric 10 becomes bulky on the first surface 10A side and has a higher hydrophobicity than the second surface 10B side. When the nonwoven fabric 10 is incorporated into an absorbent article as a surface sheet with the first layer 1 facing the skin surface, the liquid is quickly transferred to the second layer 2 to be transferred to the lower absorbent body, leaving the liquid on the skin. Make it harder.

(Constituent fibers of the first layer 1)
On the other hand, the 1st layer 1 can be made into various composition according to a use. For example, when the 1st layer 1 is used for the surface sheet of an absorptive article as a layer which touches the skin, it is excellent in liquid permeability and liquid remaining prevention property, and the soft touch structure is preferred. Like the second layer 2, it is preferably configured to contain a heat-fusible fiber, and the heat-fusible fiber preferably has an arbitrary fiber treatment agent attached thereto. Specific examples of preferred embodiments of the fiber treatment agent will be described later.

Furthermore, the 1st layer 1 is excellent in the bulk recovery property by the hot air after a load, and maintains the clearance gap between fibers and from a viewpoint of maintaining the effect | action by said heat | fever extensible fiber, a heat | fever extensible fiber and a non-heat | fever extensible fiber It is preferably blended with heat-fusible fibers. More specifically, a heat-extensible fiber whose length is extended by heating, and a non-heat-extensible heat fusion that includes two components having different melting points and is stretched and does not substantially extend its length by heating. It is preferable that it is blended with a synthetic fiber. As a constituent fiber of the first layer 1, by using a heat-extensible fiber and a non-heat-extensible heat-fusible fiber in combination, the bulk recoverability when hot air is blown onto the first layer 1 is very good. become.
An embodiment that makes use of the features of the bulkiness by the combination of the above-described heat-extensible fibers and non-heat-stretchable heat-fusible fibers and the bulkiness recoverability by hot air after loading will be described later with reference to FIG. .

  Specific examples of the heat-extensible fibers are as described above. The non-heat-extensible heat-fusible fiber combined with this includes a high-melting-point component and a low-melting-point component, and the low-melting-point component is continuously present in the length direction at least part of the fiber surface. Bicomponent composite fibers are preferred. There are various forms such as a core-sheath type and a side-by-side type in the form of the non-heat-extensible heat-fusible fiber, and any form can be used. The non-heat-extensible heat-fusible fiber is preferably stretched at the raw material stage. The term “drawing treatment” as used herein refers to a drawing operation that is usually performed on an undrawn yarn at a draw ratio of about 2 to 6 times.

  The mixing ratio between the heat-extensible fibers and the non-heat-extensible heat-fusible fibers is one of the factors affecting the hydrophilicity / hydrophobicity of the entire first layer 1. Moreover, it is also one of the factors of the ease of bulk recovery when hot air is blown onto the first layer 1. From these viewpoints, the mixing ratio of the heat-extensible fiber and the heat-fusible conjugate fiber contained in the first layer 1 is 10/90 to 90/10, particularly 30/70 to 70/30, by mass ratio. In particular, it is preferable to set 40/60 to 60/40. Thereby, it becomes easier to recover the bulk of the nonwoven fabric with hot air, and it is possible to obtain a nonwoven fabric with better touch and dryness than using each fiber alone.

  In the first layer 1, the intersection of the heat-extensible fibers, the intersection of the non-heat-extensible heat-fusible fibers, and the intersection of the heat-extensible fibers and the non-heat-extensible heat-fusible fibers are air-through. It is preferable to heat-seal by the method. Thereby, the recoverability of the bulk when hot air is blown onto the first layer 1 becomes remarkable. Further, fuzz on the surface of the first layer 1 is less likely to occur. Whether or not the intersection of the fibers is thermally fused is determined by observing the first layer 1 with a scanning electron microscope.

  The fusing temperature of the non-heat extensible heat fusible fiber is preferably close to the fusing temperature of the heat extensible fiber. Thereby, the heat-extensible fibers, the non-heat-extensible heat-fusible fibers, and the heat-extensible fibers and the non-heat-extensible heat-fusible fibers can be successfully fused. From this point of view, when the fusion temperature of the non-heat-extensible heat-fusible fiber is T1, and the fusion temperature of the heat-extensible fiber is T2, the temperature difference between T1 and T2 may be within 20 ° C. preferable. Since it is not easy to strictly measure the fiber fusion temperature, the melting temperature of the resin involved in the fusion (that is, the low melting point resin) is replaced with the fusion temperature. The method for measuring the melting point is as described above.

  From the viewpoint of successfully fusing the heat-extensible fiber and the non-heat-extensible heat-fusible fiber, the low melting point component in the non-heat-extensible heat-fusible fiber and the second in the heat-extensible fiber. When the resin component is the same type of resin or different, it is preferable that the resin component has compatibility.

<Fiber treatment agent S2 used for the first layer 1>
From the viewpoint of more clearly forming the hydrophilicity gradient in the first layer 1, the fiber treatment agent attached to the constituent fibers preferably contains the above-mentioned (A) polyorganosiloxane (used in the first layer 1). This fiber treatment agent may be referred to as S2). The hydrophilicity of the first layer 1 is partially lowered by the action of the component (A) at the time of the hot air spraying process described later, from the first surface 1A side of the first layer 1 toward the second surface 1B side. A hydrophilicity gradient can be formed to increase the hydrophilicity. Further, as described above, also in the second layer 2, the above-mentioned (A) polyorganosiloxane is adhered to the heat-fusible fiber, and the first surface 2A side of the second layer 2 by the action of the component (A). The hydrophilicity of the second layer 2 is lowered and the hydrophilicity is increased from the first surface 2A side to the second surface side 2B. Due to the two-layer hydrophilicity gradient, various aspects of the hydrophilicity gradient can be formed in the thickness direction of the nonwoven fabric 10 as a whole. The specific mode will be described later.
The content of the component (A) is preferably the same as the content of the component (A) in the second layer 2. In this case, various components can be employed together with the component (A), and examples include those shown as “other components” in the fiber treatment agent S1 of the second layer 2.

<Fiber treatment agent S3 used for the first layer 1>
Furthermore, from the viewpoint of more clearly forming the gradient of hydrophilicity in the first layer 1, the fiber treatment agent attached to the constituent fibers preferably contains the following components.
That is, the fiber treatment agent is represented by the following general formula (II) in addition to (A) polyorganosiloxane and (B) phosphate ester type anionic surfactant used for the second layer 2. It is preferable to include an anionic surfactant (this fiber treatment agent used in the first layer 1 may be referred to as S3). Thereby, the hydrophilicity gradient in which the hydrophilicity increases from the first surface 1A to the second surface 1B of the first layer 1 is more easily formed.

  In the formula, Z represents an ester group, an amide group, an amine group, a polyoxyalkylene group, an ether group or a linear or branched alkyl chain having 1 to 12 carbon atoms, which may contain a double bond. Z is preferably a linear or branched alkyl chain having 1 to 8 carbon atoms, and more preferably a linear or branched alkyl chain having 1 to 4 carbon atoms.

R ² and R ³ each independently represents an ester group, an amide group, a polyoxyalkylene group, an ether group or a linear or branched alkyl group having 2 to 16 carbon atoms, which may contain a double bond. Represent. A linear or branched alkyl chain having 4 to 14 carbon atoms is preferable, and a linear or branched alkyl chain having 6 to 12 carbon atoms is more preferable.

X represents _-SO 3 M, -OSO ₃ M or -COOM, M represents H, Na, K, Mg, Ca or ammonium.

  A component (D) points out the component which does not contain the alkyl phosphate ester which is a component (B). Moreover, a component (D) can be used individually by 1 type or in mixture of 2 or more types.

Examples of the anionic surfactant in which X in the general formula (II) is —SO ₃ M, that is, the hydrophilic group is a sulfo group or a salt thereof, include a dialkylsulfonic acid or a salt thereof. Specific examples of the dialkyl sulfonic acid include dioctadecyl sulfosuccinic acid, didecyl sulfosuccinic acid, ditridecyl sulfosuccinic acid, di-2-ethylhexyl sulfosuccinic acid, and the like, and dicarboxylic acids such as dialkyl sulfosuccinic acid and dialkyl sulfoglutaric acid. Saturated fatty acids and unsaturated fatty acids such as 2-sulfonadecanoic acid 1-ethyl ester (or amide) sodium salt and 2-sulfohexadecanoic acid 1-ethyl ester (or amide) sodium salt Alpha sulfo fatty acid alkyl esters (or amides) sulfonated at the α-position of esters (or amides), dialkyl alkenes obtained by sulfonating internal olefins of hydrocarbon chains and unsaturated fatty acids Such as sulfonic acid can be mentioned. The number of carbon atoms in each of the two-chain alkyl groups of the dialkylsulfonic acid is preferably 4 or more and 14 or less, particularly 6 or more and 10 or less.

  Specific examples of the anionic surfactant in which the hydrophilic group is a sulfo group or a salt thereof include the following anionic surfactants.

Examples of the anionic surfactant in which X in the general formula (II) is —OSO ₃ M, that is, the hydrophilic group is a sulfate group or a salt thereof, include dialkyl sulfates. Specific examples thereof include compounds obtained by sulfating alcohols having a branched chain such as 2-ethylhexyl sulfate sodium salt and 2-hexyldecyl sulfate sodium salt, polyoxyethylene sulfate 2-hexyldecyl sulfate and polyoxyethylene sulfate 2- A compound in which a POE chain is introduced between an alcohol having a branched chain such as hexyldecyl and a sulfate group, or 12-sulfate stearic acid 1-methyl ester (or amide) 3-sulfate hexanoic acid 1-methyl ester (or And a compound obtained by sulfating a hydroxy fatty acid ester (or amide) such as amide).

  Specific examples of the anionic surfactant in which the hydrophilic group is a sulfate group or a salt thereof include the following anionic surfactants.

  Examples of the anionic surfactant in which X in the general formula (II) is —COOM, that is, the hydrophilic group is a carboxy group or a salt thereof include dialkylcarboxylic acids. Specific examples thereof include compounds in which the hydroxy moiety of hydroxy fatty acid such as 11-ethoxyheptadecane carboxylic acid sodium salt and 2-ethoxypentacarboxylic acid sodium salt is alkoxylated and the fatty acid moiety is sodiumated, and amino acids such as sarcosine and glycine. Examples thereof include a compound obtained by reacting an amino group with an alkoxylated hydroxy fatty acid chloride to sodiumize the carboxylic acid in the amino acid part, a compound obtained by reacting an amino group of arginic acid with a fatty acid chloride, and the like.

  Specific examples of the anionic surfactant in which the hydrophilic group is a carboxy group or a salt thereof include the following anionic surfactants.

In the present invention, by using the fiber treatment agent S3 in which the component (D) and the component (A) are blended, the heat-fusible fiber treated with the fiber treatment agent S3 is reduced in hydrophilicity by heat treatment. It becomes easy to do. This is more likely to have a lower hydrophilicity than the fiber treatment agent S1 in which the component (A) and the component (C) used for the second layer 2 are blended.
The reason is that the above-described polyorganosiloxane further promotes the penetration of an anionic surfactant having two or more alkyl chains into the fiber. As a result, the hydrophilicity of the fiber surface tends to decrease due to heat treatment. This is because the polysiloxane chain of the polyorganosiloxane and the alkyl chain of the anionic surfactant are incompatible with each other, and when the fiber is heated and melted into the more easily adaptable hydrophobic heat-fusible fiber, Presumed to occur due to penetration of anionic surfactant. Further, the anionic surfactant represented by the general formula (II) has a bulky alkyl group and can penetrate into the hydrophobic heat-fusible fiber so as to enclose the hydrophilic group. . Thus, due to the difference in the alkyl chain, the hydrophilicity of the fiber surface of the combination of the component (D) and the component (A) is more likely to be reduced by heat treatment than the combination of the component (C) and the component (A).

  The content ratio of the component (D) in the fiber treatment agent S3 is preferably 1% by mass or more, more preferably 5% by mass or more, from the viewpoint of increasing the change in hydrophilicity due to heat treatment. Moreover, when hydrophilicity becomes high too much, it is 20 mass% or less from a viewpoint which it becomes easy to have a liquid and impairs dryness, More preferably, it is 13 mass% or less. The content of the component (D) is preferably 1% by mass or more and 20% by mass or less, and more preferably 5% by mass or more and 13% by mass or less.

Moreover, it is preferable that content of a component (A) and a component (B) shall be the range of content of each of the component (A) and component (B) described about the above-mentioned 2nd layer 2, respectively.
In particular, when the nonwoven fabric 10 is a surface sheet with the first layer 1 side facing the skin, the content of the component (A) is within the above range from the viewpoint of facilitating absorption of the liquid on the first surface 10A. It is preferable that Furthermore, the content of the component (A) in the fiber treatment agent S3 may be within the above range from the viewpoint of preventing the liquid flow distance from increasing and increasing the amount of excretory liquid adhering to the skin. preferable.

  The content ratio of the polyorganosiloxane of the component (A) and the anionic surfactant of the component (D) in the fiber treatment agent S3 is a mass ratio, preferably 1: 3 to 4: 1, more preferably 1: 2. To 3: 1. The content ratio of the polyorganosiloxane of component (A) and the alkyl phosphate ester of component (B) in the fiber treatment agent S3 is a mass ratio, preferably 1: 5 to 10: 1, more preferably 1 : 2 to 3: 1.

<Fiber treatment agent S4 used for the first layer 1>
Furthermore, in the first layer 1, from the viewpoint of more clearly forming the gradient of hydrophilicity, the fiber treatment agent attached to the constituent fibers is changed to (E) polyoxyalkylene-modified component (A) and component (B). It is preferable to include one added with a polyhydric alcohol fatty acid ester (this fiber treatment agent used in the first layer 1 may be referred to by reference numeral S4).

  The polyoxyalkylene-modified polyhydric alcohol fatty acid ester as the component (E) is more likely to penetrate into the heat-fusible fiber than the component (D) described above. Therefore, the combination of the component (A), the component (B), and the component (E) forms a hydrophilicity gradient more clearly in the nonwoven fabric 10 than the combination of the component (A), the component (B), and the component (D). can do. Thereby, it becomes easy to form the hydrophilicity gradient which becomes hydrophilic more clearly toward the 2nd surface 1B side from the 1st surface 1A side of a 1st layer.

[Polyoxyalkylene-modified polyhydric alcohol fatty acid ester: component (E)]
The polyoxyalkylene-modified polyhydric alcohol fatty acid ester component (E) makes the decrease in hydrophilicity due to heat treatment during the production of the nonwoven fabric more remarkable, that is, the hydrophilicity of a desired portion in the nonwoven fabric is significantly improved. It is a kind of nonionic surfactant that can be lowered. Component (E) is a kind of a polyhydric alcohol fatty acid ester obtained by esterifying a hydroxyl group of a polyhydric alcohol with a fatty acid, and is a modified product obtained by adding an alkylene oxide to the polyhydric alcohol fatty acid ester. Component (E) can be produced according to a conventional method, and can be produced, for example, according to Japanese Patent Application Laid-Open No. 2007-91852.

  Examples of the polyhydric alcohol that is one of the raw materials of the component (E) (or polyhydric alcohol fatty acid ester) include, for example, ethylene glycol, diethylene glycol, polyethylene glycol (molecular weight of 200 to 11000), propylene glycol, dipropylene glycol, and polypropylene. Glycol (molecular weight 250 to 4000), 1,3-butylene glycol, glycerin, polyglycerin (degree of polymerization 2 to 30), erythritol, xylitol, sorbitol, mannitol, inositol, sorbitan, sorbide, sucrose, trehalose, erulose, Examples thereof include lactosucrose, cyclodextrin, maltitol, lactitol, palatinit, panitol, and reduced starch syrup. Preferred are polyethylene glycol, glycerin, erythritol, sorbitol, sorbitan, sorbide, and sucrose, and particularly preferred are sorbitol, sorbitan, and sorbide.

  Examples of the fatty acid that is another raw material of the component (E) (or the polyhydric alcohol fatty acid ester) include, for example, saturated or unsaturated fatty acids having 6 to 22 carbon atoms, mixed fatty acids containing these as main components, Alternatively, branched chain fatty acids having 8 to 36 carbon atoms can be mentioned. The fatty acid may partially contain a hydroxyl group. Specifically, octanoic acid, nonanoic acid, decanoic acid, undecanoic acid, dodecanoic acid, tetradecanoic acid, hexadecanoic acid, octadecanoic acid, cis-9-octadecenoic acid, eicosanoic acid, docosanoic acid, tetracosanoic acid, hexacosanoic acid, octacosanoic acid , 2-ethylhexylic acid, isostearic acid, and the like. Naturally derived mixed fatty acids such as coconut oil fatty acid and beef tallow fatty acid may be used, preferably a fatty acid having 8 to 18 carbon atoms, particularly preferably dodecanoic acid, Octadecanoic acid, cis-9-octadecenoic acid.

When the main component of the polyhydric alcohol fatty acid ester constituting the component (E) is to increase the hydrophobic chain and increase the hydrophobicity, the molecular shape is not increased linearly but increased three-dimensionally. Thus, from the viewpoint of obtaining a shape that can be easily taken into the fiber, an esterified product of a trivalent or higher alcohol and an esterification rate of the alcohol component of 90% or higher are preferable. Here, the main component is the most abundant component in the polyhydric alcohol fatty acid ester, and is preferably contained in an amount of 50% by mass or more based on the total mass of the polyhydric alcohol fatty acid ester. For example, examples of the trivalent alcohol include glycerin, examples of the tetravalent alcohol include erythritol, and examples of the pentavalent alcohol include xylitol.
Particularly preferred as the polyhydric alcohol fatty acid ester constituting the component (E) is castor oil (hardened castor oil). Castor oil is a glycerin fatty acid ester derived from the seeds of castor, which is a plant belonging to the family Dromeliaceae, and about 90% of the constituent fatty acid is ricinoleic acid. That is, as component (E), ester oil of glycerin and a fatty acid mainly composed of ricinoleic acid is preferable.

In the component (E), examples of the alkylene oxide added to the polyhydric alcohol fatty acid ester include ethylene oxide, propylene oxide, butylene oxide, and the like. Particularly preferred as component (E) is a polyoxyethylene (POE) -modified polyhydric alcohol fatty acid ester in which the alkylene oxide added to the polyhydric alcohol fatty acid ester is ethylene oxide, and particularly preferred is the polyhydric alcohol fatty acid ester. Is POE-modified castor oil (POE-modified hardened castor oil), which is castor oil (hardened castor oil).
In component (E), the number of moles of alkylene oxide added to the polyhydric alcohol fatty acid ester is preferably more than 20 moles from the viewpoint of improving the liquid absorption performance of the nonwoven fabric (reducing the amount of remaining liquid and reducing the amount of liquid flow). 40 mol or more is particularly preferable. However, if the number of added moles of alkylene oxide is too large, the hydrophilicity of the nonwoven fabric will increase too much. For example, when the nonwoven fabric is used as a surface sheet in an absorbent article, it may lead to an increase in the amount of liquid remaining. Therefore, the added mole number is preferably 80 moles or less, more preferably 60 moles or less.

  The content ratio of the component (E) of S4 in the fiber treatment agent is the total mass of the fiber treatment agent from the viewpoint of increasing the hydrophilicity of the nonwoven fabric and remarkably expressing the effect of reducing the hydrophilicity due to heat treatment during the production of the nonwoven fabric. On the other hand, it is preferably 5% by mass or more, more preferably 10% by mass or more, and preferably from the viewpoint of suppressing an increase in the remaining amount of liquid due to strong hydrophilization, with respect to the total mass of the fiber treatment agent. It is 20 mass% or less, More preferably, it is 15 mass% or less.

The content ratio of the polyorganosiloxane of component (A) to the polyoxyalkylene-modified polyhydric alcohol fatty acid ester of component (E) is preferably a mass ratio, preferably 1: 2 to 3: 1, more preferably 1: 1. To 2: 1.
The content ratio of the polyorganosiloxane of the component (A) and the alkyl phosphate ester of the component (B) is a mass ratio, preferably 1: 5 to 10: 1, more preferably 1: 2 to 3: 1.

  The content of each of the component (A) and the component (B) is preferably in the range of the content of each of the component (A) and the component (B) described for the second layer 1 described above.

<Fiber treatment agent S5 used for the first layer 1>
Further, from the viewpoint of more clearly forming the hydrophilicity gradient in the first layer 1, the fiber treatment agent attached to the constituent fibers is the component (A), component (B), component (D) and component (E) described above. (This fiber treatment agent used for the first layer 1 may be referred to as S5).

  The content ratio of the component (D) and the component (E) in the fiber treatment agent S5 is preferably a mass ratio of 4: 1 to 1: 4, more preferably 2: 1 to 1: 2.

  In the above content ratio, the content ratio of the component (D) in the fiber treatment agent S5 is preferably 1% by mass or more, more preferably 5% by mass or more, from the viewpoint of increasing the change in hydrophilicity due to heat treatment. Moreover, when hydrophilicity becomes high too much, from a viewpoint which becomes easy to have a liquid and impairs dryness, Preferably it is 20 mass% or less, More preferably, it is 10 mass% or less. The content of the component (E) is preferably 5% by mass or more and 20% by mass or less, and more preferably 10% by mass or more and 15% by mass or less.

  The content of each of the component (A) and the component (B) is preferably in the range of the content of each of the component (A) and the component (B) described for the second layer 2 described above.

  The content ratio of the polyorganosiloxane of the component (A) in the fiber treatment agent S5 and the anionic surfactant represented by the following general formula (II) which is the component (D) is a mass ratio, preferably 1: It is 3 to 4: 1, more preferably 1: 2 to 3: 1. The content ratio of the polyorganosiloxane of component (A) to the polyoxyalkylene-modified polyhydric alcohol fatty acid ester of component (E) in the fiber treatment agent S5 is preferably a mass ratio, preferably 1: 2 to 3: 1. Preferably it is 1: 1 to 2: 1.

In the formula, Z represents an ester group, an amide group, an amine group, a polyoxyalkylene group, an ether group or a linear or branched alkyl chain having 1 to 12 carbon atoms, which may contain a double bond. R ² and R ³ each independently represents an ester group, an amide group, a polyoxyalkylene group, an ether group or a linear or branched alkyl group having 2 to 16 carbon atoms, which may contain a double bond. Represent. X represents —SO ₃ M, —OSO ₃ M or —COOM, and M represents H, Na, K, Mg, Ca or ammonium.
A more preferred range of the Z, R ^2, R ³ and X may be similar to that described in the fiber treatment agent S3 of the above.

  The content ratio of the polyorganosiloxane of component (A) to the alkyl phosphate ester of component (B) in the fiber treatment agent S5 is preferably a mass ratio, preferably 1: 5 to 10: 1, more preferably 1. : 2 to 3: 1.

  In said fiber processing agent S2, S3, S4, and S5, in addition to the content component mentioned above, what was shown as "other components" by the fiber processing agent S1 of the 2nd layer 2 may be included.

  The amount (content) of the fiber treatment agent S2, S3, S4 and S5 attached to the heat-fusible fiber in the first layer 1 is a ratio to the total mass of the heat-fusible fiber excluding the fiber treatment agent. From the viewpoint of enhancing hydrophilicity, 0.1% by mass or more is preferable, 0.2% by mass or more is more preferable, and 0.3% by mass or more is more preferable. Further, the upper limit is preferably 1.5% by mass or less, more preferably 1.0% by mass or less, and further preferably 0.5% by mass or less from the viewpoint of reducing the contamination of the nonwoven fabric processing machine. For example, the amount of the fiber treatment agents S2, S3, S4 and S5 attached to the heat-fusible fiber is 0.1% by mass or more as a ratio to the total mass of the heat-fusible fiber excluding the fiber treatment agent. 1.5 mass% or less is preferable, 0.2 mass% or more and 1.0 mass% or less are more preferable, and 0.3 mass% or more and 0.5 mass% or less are more preferable.

  In the first layer 1 and the second layer 2 of the nonwoven fabric 10, various known methods can be employed without particular limitation as a method for attaching the above-described fiber treatment agent to the fiber surface. For example, application by spraying, application by slot coater, application by roll transfer, immersion in a hydrophilic oil, and the like can be mentioned. These treatments may be performed on the fibers before being formed into a web, or may be performed after the fibers are formed into a web by various methods. The fiber having the fiber treatment agent attached to the surface thereof is dried at a temperature sufficiently lower than the melting point of the ethylene resin (for example, 120 ° C. or less) by, for example, a hot air blowing dryer.

(Specific example of hydrophilicity gradient)
A specific example of the hydrophilicity gradient of the nonwoven fabric 10 will be described below with reference to FIG. The nonwoven fabric 10 here is demonstrated as a nonwoven fabric obtained by the air through manufacturing method.
The nonwoven fabric 10 has a first layer 1 and a second layer 2. The first layer 1 and the second layer 2 are in direct contact with each other, and there are no other layers interposed between the two layers. Each of the first layer 1 and the second layer 2 is a single fiber layer, and is not composed of a multi-layer laminate that is further subdivided. The 1st layer 1 and the 2nd layer 2 are couple | bonded in the whole area of those opposing surfaces, and the space | gap does not arise between both layers 1 and 2. FIG. In FIG. 3, the first layer 1 and the second layer 2 are represented by the same thickness, but this is because the layers 1 and 2 are schematically shown. The thickness of the layer 1 and the second layer 2 may be different.

  Both the first layer 1 and the second layer 2 are made of randomly deposited fibers. The fibers constituting the first layer 1 are fused by an air-through method at the intersections of the fibers. The same applies to the second layer 2. Further, at the boundary between the first layer 1 and the second layer 2, the intersection of the fibers constituting the first layer 1 and the fibers constituting the second layer 2 is fused by an air-through method. In addition, the fibers constituting the first layer 1 may be bonded by means other than air-through fusion. For example, they may be additionally bonded by means such as fusion by hot embossing, entanglement by a high-pressure jet flow, adhesion by an adhesive, or the like. The same applies to the second layer 2 and also at the boundary between the first layer 1 and the second layer 2.

  In the nonwoven fabric 10, the first layer 1 is virtually divided into two in the thickness direction, and a portion far from the second layer 2 out of the two divided portions is the first layer first portion 11. And a portion closer to the second layer is defined as a first layer second portion 12. Further, the second layer 2 is virtually divided into two in the thickness direction, and a portion closer to the first layer 1 out of the two divided portions is defined as a second layer first portion 21, A part far from the first layer 1 is defined as a second layer second part 22. Since the first layer 1 and the second layer 2 are each composed of a single layer, the second layer first portion 21 and the second layer are provided between the first layer first portion 11 and the first layer second portion 12. There is no boundary between the second part 22.

In the above classification, when the nonwoven fabric 10 is obtained by spraying a hot cloth from the first surface 10A side in a two-layer laminated state, the following can be said when the hydrophilicity of each part is compared.
(11) In the first layer 1, the first layer second portion 12 has higher hydrophilicity than the first layer first portion 11 (first layer first portion 11 <first layer second portion 12). .
(12) In the second layer 2, the hydrophilicity of the second layer second portion 22 is higher than that of the second layer first portion 21 (second layer first portion 21 <second layer second portion 22). .

  Due to the hydrophilicity gradient in the thickness direction as in the above (11) and (12), when the liquid is supplied to the first surface 10A side, the liquid quickly passes through the nonwoven fabric. Become. Accordingly, it is difficult for the liquid to flow along the surface on the first surface 10A side. As a result, it is difficult for the liquid to remain on the surface on the first surface 10A side, which is the surface (liquid receiving surface) to which the liquid is supplied. These remarkable effects become particularly remarkable when the nonwoven fabric 10 is applied to the top sheet of the absorbent article with the first surface 10A side as the skin facing surface.

In order to provide the hydrophilicity gradient of (11), it is preferable that the first layer 1 includes heat-fusible fibers to which any of the fiber treatment agents S2 to S5 is attached as described above. . More preferably, it is a blend of heat-extensible fibers and non-heat-extensible heat-fusible fibers. On the other hand, in order to provide the hydrophilicity gradient of (12), it is preferable that the heat-fusible fiber to which the fiber treatment agent S1 is attached in the second layer 2 is included as described above. At the same time, it is preferable to appropriately control the hot air blowing conditions in the air-through method described later, that is, the temperature and air volume of the hot air.
In this case, the “gradient” of the hydrophilicity of the first layer 1 may be such that the hydrophilicity gradually increases from the first part 11 toward the second part 12 as described above, or from the first part 11 The hydrophilicity may increase stepwise toward the second portion 12. Similarly, as described above, the “gradient” of the hydrophilicity of the second layer 2 may be such that the hydrophilicity gradually increases from the first part 21 toward the second part 22 or from the first part 21. The hydrophilicity may increase stepwise toward the second portion 22. In any case of the first layer 1 and the second layer 2, the hydrophilicity is preferably gradually increased.

The hydrophilicity in a nonwoven fabric can be shown by the relative comparison of the contact angle of a constituent fiber. A small contact angle value indicates that the hydrophilicity is high, and a large contact angle value indicates that the hydrophilicity is low.
In the 1st layer 1 of the nonwoven fabric 10, it is preferable that the contact angle of the water with respect to the fiber contained in the 1st layer 1st part 11 is 70 degree | times or more, especially 72 degree | times or more. Further, it is preferably 85 degrees or less, particularly 82 degrees or less. For example, the contact angle of water with respect to the fibers contained in the first layer first portion 11 is preferably 70 degrees or more and 85 degrees or less, and preferably 72 degrees or more and 82 degrees or less.
On the other hand, on the condition that the contact angle of water with respect to the fibers contained in the first layer second portion 12 is smaller than the contact angle of water with respect to the fibers contained in the first layer first portion 11, it is 60 degrees or more, particularly 65. It is preferable that it is more than degree. Moreover, it is preferable that it is 80 degrees or less, especially 75 degrees or less. For example, the contact angle of water with respect to the fibers contained in the first layer second portion 12 is preferably 60 degrees or more and 80 degrees or less, and more preferably 65 degrees or more and 75 degrees or less.

In the second layer 2 of the nonwoven fabric 10, it is preferable that the contact angle of water with respect to the fibers contained in the second layer first portion 21 is 50 degrees or more, particularly 55 degrees or more. Moreover, it is preferable that it is 78 degrees or less, especially 73 degrees or less. For example, the contact angle of water with respect to the fibers contained in the second layer first portion 21 is preferably 50 degrees to 78 degrees, and more preferably 55 degrees to 73 degrees.
On the other hand, if the contact angle of water with respect to the fibers contained in the second layer second portion 22 is smaller than the contact angle of water with respect to the fibers contained in the second layer first portion 21, it is 20 degrees or more, particularly 30. It is preferable that it is more than degree. Moreover, it is preferable that it is 75 degrees or less, especially 70 degrees or less. For example, the contact angle of water with respect to the fibers contained in the second layer second portion 22 is preferably 20 degrees or more and 75 degrees or less, and more preferably 30 degrees or more and 70 degrees or less.

(Measurement method of contact angle)
A fiber is taken out from a predetermined portion in the thickness direction of the nonwoven fabric, and the contact angle of water with the fiber is measured. As a measuring device, an automatic contact angle meter MCA-J manufactured by Kyowa Interface Science Co., Ltd. is used. Distilled water is used to measure the contact angle.
The amount of liquid discharged from an ink jet type water droplet discharge part (manufactured by Cluster Technology, Inc., pulse injector CTC-25 having a discharge part pore diameter of 25 μm) is set to 20 picoliters, and a water drop is dropped directly above the fiber. The state of dripping is recorded on a high-speed recording device connected to a horizontally installed camera. The recording device is preferably a personal computer incorporating a high-speed capture device from the viewpoint of image analysis later. In this measurement, an image is recorded every 17 ms.
In the recorded video, the first image of water drops on the fiber taken out from the non-woven fabric is attached to the attached software FAMAS (software version is 2.6.2, analysis method is droplet method, analysis method is θ / 2 method) The image processing algorithm is non-reflective, the image processing image mode is frame, the threshold level is 200, and no curvature correction is performed). Based on this, the angle formed by the surface of the water droplet that touches the air and the fiber is calculated as the contact angle. The fiber taken out from the nonwoven fabric is cut into a fiber length of 1 mm, and the fiber is placed on a sample table of a contact angle meter and kept horizontal. Two different contact angles are measured for each fiber. N = 5 contact angles are measured to one decimal place, and a value obtained by averaging a total of 10 measured values (rounded to the second decimal place) is defined as the contact angle.

The relationship between the hydrophilicity between the first layer 1 and the second layer 2 is that the fiber diameter in the second layer 2, the amount of the component (A) and component (C) of the fiber treatment agent, the fiber in the first layer 1 The amount of adhesion of the component (A) of the diameter and the fiber treatment agent, the amount of adhesion of the component (A) and the component (D), the amount of adhesion of the component (A) and the component (E), or the component (A) and the component (D ) And the amount of component (E) attached. Further, it varies depending on the hot air blowing conditions in the air-through method, which will be described later, that is, the temperature and air volume of the hot air. By appropriately adjusting these conditions, for example, the following relationship can be obtained.
(13) The second layer first portion 21 is higher in hydrophilicity than the first layer second portion 12.
(14) The hydrophilicity of the second layer first portion 21 is higher than that of the first layer first portion 11.
(15) The first layer second portion 12 is higher in hydrophilicity than the second layer first portion 21.
(16) The second layer second portion 22 has higher hydrophilicity than the first layer second portion 12.
(17) The first layer first portion 11 is higher in hydrophilicity than the second layer first portion 21.
(18) The first layer second portion 12 is higher in hydrophilicity than the second layer second portion 22.

  When the relationship (13) is added to the above (11) and (12), the first layer first part 11 <the first layer second part 12 <the second layer first part 21 <the second layer second part 22 Become. When there is such a hydrophilicity gradient, the nonwoven fabric 10 has a hydrophilicity gradient that is connected from the first surface 10A side to the second surface 10B side, and the liquid supplied to the first surface 10A side is directed to the second surface 10B. And led quickly. That is, the force to draw the liquid is increased, the liquid at the top is drawn into the lower layer, and the apparent whiteness is increased.

  In this case, the preferable contact angle ranges of the first layer first portion 11, the first layer second portion 12, the second layer first portion 21, and the second layer second portion 22 are the same as described above. Is preferred.

  From the viewpoint of smoother liquid permeation from the first layer 1 to the second layer 2, the contact angle of water with respect to the fibers contained in the first layer second portion 12 and the second layer first portion 21 are included. The difference from the contact angle of water with respect to the fibers (first layer second portion 12-second layer first portion 21) is preferably 1 degree or more, particularly preferably 10 degrees or more, 30 degrees or less, particularly 25 degrees or less. It is preferable that For example, the difference is preferably 1 degree or more and 30 degrees or less, more preferably 10 degrees or more and 25 degrees or less.

  From the same viewpoint as described above, the difference between the contact angle of water with respect to the fibers contained in the first layer first portion 11 and the contact angle of water with respect to the fibers contained in the second layer second portion 22 (first layer first). The portion 11-the second layer second portion 22) is 2 degrees or more, particularly 10 degrees, provided that the contact angle difference between the first layer second portion 12 and the second layer first portion 21 is larger than that described above. It is preferable that the angle be 65 degrees or less, particularly 50 degrees or less. For example, the difference is preferably 2 ° to 65 °, more preferably 10 ° to 50 °.

When the relations (14) to (16) are added to the above (11) and (12), the first layer first portion 11 <second layer first portion 21 <first layer second portion 12 <second layer first. Two sites 22 are obtained. In this case, the hydrophilicity does not increase sequentially from the first layer 10 side toward the second layer 20 side, but between the first layer second portion 12 and the second layer first portion 21. The relationship of hydrophilicity is reversed.
The nonwoven fabric 10 having such a relationship of hydrophilicity has the following effects in addition to the effects described so far. That is, the effect that the liquid once transmitted through the nonwoven fabric 10 is difficult to return due to the relationship of the hydrophilicity being reversed between the first layer second portion 12 and the second layer first portion 21. Play. Furthermore, there is an effect that the liquid permeates through the nonwoven fabric 10 while the liquid diffuses in the plane direction of the nonwoven fabric 10. The effect that the liquid is difficult to reverse is that when the nonwoven fabric 10 is used as the top sheet of the absorbent article, the liquid once absorbed by the absorbent body is difficult to return even if it receives the body pressure of the wearer. It is advantageous. In addition, the effect that the liquid permeates while diffusing in the plane direction of the nonwoven fabric 10 is that when the nonwoven fabric 10 is used as the surface sheet of the absorbent article, the liquid can be absorbed in all parts in the plane direction of the absorbent body. It is possible to effectively utilize the absorption performance of the absorber, and as a result, it is possible to reduce the liquid residue, which is advantageous.

In the 1st layer 1 in this case, it is preferable that the contact angle of water with respect to the fiber contained in the 1st layer 1st part 11 is 70 degrees or more, especially 72 degrees or more. Further, it is preferably 85 degrees or less, particularly 82 degrees or less. For example, the contact angle of water with respect to the fibers contained in the first layer first portion 11 is preferably 70 degrees or more and 85 degrees or less, and preferably 72 degrees or more and 82 degrees or less.
On the other hand, on the condition that the contact angle of water with respect to the fibers contained in the first layer second portion 12 is smaller than the contact angle of water with respect to the fibers contained in the first layer first portion 11, it is 50 degrees or more, particularly 55. It is preferable that it is more than degree. Moreover, it is preferable that it is 75 degrees or less, especially 70 degrees or less. For example, the contact angle of water with respect to the fibers contained in the first layer second portion 12 is preferably 50 degrees or greater and 75 degrees or less, and preferably 55 degrees or greater and 70 degrees or less.

In the second layer 2, the contact angle of water with respect to the fibers contained in the second layer first portion 21 is preferably 60 degrees or more, particularly 65 degrees or more. Moreover, it is preferable that it is 80 degrees or less, especially 75 degrees or less. For example, the contact angle of water with respect to the fibers contained in the second layer first portion 21 is preferably 60 degrees or more and 80 degrees or less, and more preferably 65 degrees or more and 75 degrees or less.
On the other hand, if the contact angle of water with respect to the fibers contained in the second layer second portion 22 is smaller than the contact angle of water with respect to the fibers contained in the second layer first portion 21, it is 30 degrees or more, particularly 40. It is preferable that it is more than degree. Moreover, it is preferable that it is 70 degrees or less, especially 65 degrees or less. For example, the contact angle of water with respect to the fibers contained in the second layer second portion 22 is preferably 30 degrees or more and 70 degrees or less, and preferably 40 degrees or more and 65 degrees or less.

  From the viewpoint of making the above effect more remarkable, the difference between the contact angle of water with respect to the fibers contained in the second layer first portion 21 and the contact angle of water with respect to the fibers contained in the first layer second portion 12 (Second layer first portion 21-first layer second portion 12) is preferably 1 degree or more, and particularly preferably 2 degrees or more. Further, it is preferably 30 degrees or less, particularly preferably 25 degrees or less. For example, the difference is preferably 1 to 30 degrees, more preferably 2 to 25 degrees.

  Further, from the viewpoint of smoother liquid permeation from the first layer 1 to the second layer 2, the contact angle of water with respect to the fibers contained in the first layer first portion 11 and the second layer second portion 22 The difference from the contact angle of water with respect to the contained fibers (first layer first portion 11 -second layer second portion 22) is preferably 2 degrees or more, particularly preferably 5 degrees or more, and 55 degrees or less, particularly 45. Or less. For example, the difference is preferably 2 ° to 55 °, more preferably 5 ° to 45 °.

When the relations (17) and (18) are added to the above (11) and (12), the second layer first part 21 <the first layer first part 11 <the second layer second part 22 <the first layer first. Two sites 12 are obtained. In this case, there exists a gradient of hydrophilicity in each of the nonwoven fabrics of the first layer and the second layer, and the first layer first portion 11 and the second surface 10B side on the first surface 10A side of the nonwoven fabric 10 are present. A difference in hydrophilicity exists between the second layer 22 and the second layer 22.
The nonwoven fabric 10 having such a relationship of hydrophilicity has the following effects. That is, since the hydrophilicity of the second layer first portion 21 is the lowest, the effect of suppressing the liquid diffusion area and reversion is further increased. When the nonwoven fabric 10 is used as the top sheet of the absorbent article as described above, the effect that the liquid is difficult to return is difficult to return even if the liquid once absorbed by the absorbent body receives the body pressure of the wearer. This is advantageous.

In the 1st layer 1 in this case, it is preferable that the contact angle of water with respect to the fiber contained in the 1st layer 1st part 11 is 70 degrees or more, especially 72 degrees or more. Further, it is preferably 82 degrees or less, particularly 78 degrees or less. For example, the contact angle of water with respect to the fibers contained in the first layer first portion 11 is preferably 70 degrees or more and 85 degrees or less, and preferably 72 degrees or more and 82 degrees or less.
On the other hand, the contact angle of water with respect to the fibers contained in the first layer second portion 12 is 45 degrees or more, particularly 50, provided that the contact angle of water with respect to the fibers contained in the first layer first portion 11 is smaller. It is preferable that it is more than degree. Moreover, it is preferable that it is 73 degrees or less, especially 68 degrees or less. For example, the contact angle of water with respect to the fibers contained in the first layer second portion 12 is preferably 50 degrees or greater and 73 degrees or less, and preferably 55 degrees or greater and 68 degrees or less.

In the second layer 2, it is preferable that the contact angle of water with respect to the fibers contained in the second layer first portion 21 is 70 degrees or more, particularly 75 degrees or more. Further, it is preferably 85 degrees or less, particularly 82 degrees or less. For example, the contact angle of water with respect to the fibers contained in the second layer first portion 21 is preferably 70 degrees to 85 degrees, and more preferably 75 degrees to 80 degrees.
On the other hand, the contact angle of water with respect to the fibers contained in the second layer second portion 22 is 55 degrees or more, particularly 60, provided that the contact angle of water with respect to the fibers contained in the second layer first portion 21 is smaller. It is preferable that it is more than degree. Moreover, it is preferable that it is 75 degrees or less, especially 70 degrees or less. For example, the contact angle of water with respect to the fibers contained in the second layer second portion 22 is preferably 55 degrees or greater and 75 degrees or less, and preferably 55 degrees or greater and 70 degrees or less.

From the viewpoint of making the above effect more prominent, the difference between the contact angle of water with respect to the fibers contained in the second layer first part 21 and the contact angle of water with respect to the fibers contained in the first layer first part 11 (Second layer first portion 21-first layer second portion 12) is preferably 1 degree or more, and particularly preferably 2 degrees or more. Further, it is preferably 30 degrees or less, particularly preferably 25 degrees or less. For example, the difference is preferably 1 to 30 degrees, more preferably 2 to 25 degrees.
Further, from the viewpoint of smoother liquid permeation from the first layer 1 to the second layer 2, the contact angle of water with respect to the fibers contained in the first layer first portion 11 and the second layer second portion 22 The difference from the contact angle of water with respect to the contained fibers (first layer first portion 11 -second layer second portion 22) is preferably 2 degrees or more, particularly preferably 5 degrees or more, and 55 degrees or less, particularly 45. Or less. For example, the difference is preferably 2 ° to 55 °, more preferably 5 ° to 45 °.

When the relations (14), (15), and (18) are added to the above (11) and (12), the first layer first portion 11 <second layer first portion 21 <second layer second portion 22 <. It becomes the first layer second portion 12. In this case, there exists a gradient of hydrophilicity in each of the nonwoven fabrics of the first layer and the second layer, and the first layer first portion 11 and the second surface 10B side on the first surface 10A side of the nonwoven fabric 10 are present. A difference in hydrophilicity exists between the second layer 22 and the second layer 22.
The nonwoven fabric 10 having such a relationship of hydrophilicity has the following effects. That is, the effect that the liquid once transmitted through the nonwoven fabric 10 is difficult to return due to the relationship of the hydrophilicity being reversed between the first layer second portion 12 and the second layer first portion 21. Play. Furthermore, there is an effect that the liquid permeates through the nonwoven fabric 10 while the liquid diffuses in the plane direction inside the nonwoven fabric 10. The effect that the liquid is difficult to reverse is that when the nonwoven fabric 10 is used as the top sheet of the absorbent article, the liquid once absorbed by the absorbent body is difficult to return even if it receives the body pressure of the wearer. It is advantageous. In addition, the effect that the liquid permeates while diffusing in the plane direction of the nonwoven fabric 10 is that when the nonwoven fabric 10 is used as the surface sheet of the absorbent article, the liquid can be absorbed in all parts in the plane direction of the absorbent body. It is possible to effectively utilize the absorption performance of the absorber, and as a result, it is possible to reduce the liquid residue, which is advantageous.

In the 1st layer 1 in this case, it is preferable that the contact angle of water with respect to the fiber contained in the 1st layer 1st part 11 is 70 degrees or more, especially 72 degrees or more. Further, it is preferably 85 degrees or less, particularly 82 degrees or less. For example, the contact angle of water with respect to the fibers contained in the first layer first portion 11 is preferably 70 degrees or more and 85 degrees or less, and preferably 72 degrees or more and 82 degrees or less.
On the other hand, if the contact angle of water with respect to the fibers contained in the first layer second portion 12 is smaller than the contact angle of water with respect to the fibers contained in the first layer first portion 11, it is 30 degrees or more, particularly 40. It is preferable that it is more than degree. Moreover, it is preferable that it is 75 degrees or less, especially 70 degrees or less. For example, the contact angle of water with respect to the fibers contained in the first layer second portion 12 is preferably 30 degrees or more and 75 degrees or less, and preferably 40 degrees or more and 70 degrees or less.

In the second layer 2, it is preferable that the contact angle of water with respect to the fibers contained in the second layer first portion 21 is 70 degrees or more, particularly 75 degrees or more. Moreover, it is preferable that it is 83 degrees or less, especially 80 degrees or less. For example, the contact angle of water with respect to the fibers contained in the second layer first portion 21 is preferably 70 degrees or more and 83 degrees or less, and more preferably 75 degrees or more and 80 degrees or less.
On the other hand, the contact angle of water with respect to the fibers contained in the second layer second portion 22 is 55 degrees or more, particularly 60, provided that the contact angle of water with respect to the fibers contained in the second layer first portion 21 is smaller. It is preferable that it is more than degree. Moreover, it is preferable that it is 78 degrees or less, especially 73 degrees or less. For example, the contact angle of water with respect to the fibers contained in the second layer second portion 22 is preferably 55 degrees or greater and 78 degrees or less, and preferably 55 degrees or greater and 73 degrees or less.

From the viewpoint of making the above effect more prominent, the difference between the contact angle of water with respect to the fibers contained in the second layer first part 21 and the contact angle of water with respect to the fibers contained in the first layer first part 11 (Second layer first portion 21-first layer second portion 12) is preferably 1 degree or more, and particularly preferably 2 degrees or more. Further, it is preferably 30 degrees or less, particularly preferably 25 degrees or less. For example, the difference is preferably 1 to 30 degrees, more preferably 2 to 25 degrees.
Further, from the viewpoint of smoother liquid permeation from the first layer 1 to the second layer 2, the contact angle of water with respect to the fibers contained in the first layer first portion 11 and the second layer second portion 22 The difference from the contact angle of water with respect to the contained fibers (first layer first portion 11 -second layer second portion 22) is preferably 2 degrees or more, particularly preferably 5 degrees or more, and 55 degrees or less, particularly 45. Or less. For example, the difference is preferably 2 ° to 55 °, more preferably 5 ° to 45 °.

When the relations (15) to (17) are added to the above (11) and (12), the second layer first part 21 <the first layer first part 11 <the first layer second part 12 <the second layer first. Two sites 22 are obtained. In this case, there exists a gradient of hydrophilicity in each of the nonwoven fabrics of the first layer and the second layer, and the first layer first portion 11 and the second surface 10B side on the first surface 10A side of the nonwoven fabric 10 are present. A difference in hydrophilicity exists between the second layer 22 and the second layer 22.
The nonwoven fabric 10 having such a relationship of hydrophilicity has the following effects. That is, since the hydrophilicity of the second layer first portion 21 is the lowest, the effect of suppressing the liquid diffusion area and reversion is further increased. When the nonwoven fabric 10 is used as the top sheet of the absorbent article as described above, the effect that the liquid is difficult to return is difficult to return even if the liquid once absorbed by the absorbent body receives the body pressure of the wearer. This is advantageous.

In the 1st layer 1 in this case, it is preferable that the contact angle of water with respect to the fiber contained in the 1st layer 1st part 11 is 70 degrees or more, especially 72 degrees or more. Further, it is preferably 82 degrees or less, particularly 78 degrees or less. For example, the contact angle of water with respect to the fibers contained in the first layer first portion 11 is preferably 70 degrees or more and 85 degrees or less, and preferably 72 degrees or more and 82 degrees or less.
On the other hand, on the condition that the contact angle of water with respect to the fibers contained in the first layer second portion 12 is smaller than the contact angle of water with respect to the fibers contained in the first layer first portion 11, it is 50 degrees or more, particularly 55. It is preferable that it is more than degree. Moreover, it is preferable that it is 75 degrees or less, especially 72 degrees or less. For example, the contact angle of water with respect to the fibers contained in the first layer second portion 12 is preferably 50 degrees to 75 degrees, and more preferably 55 degrees to 72 degrees.

In the second layer 2, it is preferable that the contact angle of water with respect to the fibers contained in the second layer first portion 21 is 70 degrees or more, particularly 75 degrees or more. Further, it is preferably 85 degrees or less, particularly 82 degrees or less. For example, the contact angle of water with respect to the fibers contained in the second layer first portion 21 is preferably 70 degrees to 85 degrees, and more preferably 75 degrees to 80 degrees.
On the other hand, if the contact angle of water with respect to the fibers contained in the second layer second portion 22 is smaller than the contact angle of water with respect to the fibers contained in the second layer first portion 21, it is 30 degrees or more, particularly 40. It is preferable that it is more than degree. Moreover, it is preferable that it is 73 degrees or less, especially 70 degrees or less. For example, the contact angle of water with respect to the fibers contained in the second layer second portion 22 is preferably 30 degrees or greater and 73 degrees or less, and preferably 40 degrees or greater and 70 degrees or less.

From the viewpoint of making the above effect more prominent, the difference between the contact angle of water with respect to the fibers contained in the second layer first part 21 and the contact angle of water with respect to the fibers contained in the first layer first part 11 (Second layer first portion 21-first layer second portion 12) is preferably 1 degree or more, and particularly preferably 2 degrees or more. Further, it is preferably 30 degrees or less, particularly preferably 25 degrees or less. For example, the difference is preferably 1 to 30 degrees, more preferably 2 to 25 degrees.
Further, from the viewpoint of smoother liquid permeation from the first layer 1 to the second layer 2, the contact angle of water with respect to the fibers contained in the first layer first portion 11 and the second layer second portion 22 The difference from the contact angle of water with respect to the contained fibers (first layer first portion 11 -second layer second portion 22) is preferably 2 degrees or more, particularly preferably 5 degrees or more, and 55 degrees or less, particularly 45. Or less. For example, the difference is preferably 2 ° to 55 °, more preferably 5 ° to 45 °.

(Nonwoven fabric 20)
Next, in the nonwoven fabric provided with the above-described hydrophilicity gradient and high concealability, a preferable aspect in the case where the first layer 1 is a blend of heat-extensible fibers and non-heat-extensible heat-fusible fibers will be described. .
As shown in FIG. 4 (i) and FIG. 4 (ii), the nonwoven fabric 20 has a concavo-convex surface 51 having a concavo-convex shape on the first surface side, and the second surface side is flat or compared to the concavo-convex surface. Thus, the flat surface 52 has a small degree of unevenness. That is, the uneven surface 51 is on the first layer 1 side, and the flat surface 52 is on the second layer 2 side. The thick portion 59 and the thin portion 58 in the nonwoven fabric 20 correspond to the positions of the convex portions 69 and the concave portions 68 formed on the concave and convex surface 51 of the nonwoven fabric 20. The recess 68 includes a first linear recess 68A extending in parallel with each other and a second linear recess 68B extending in parallel with each other, and the first linear recess 68A and the second linear recess 68B. And intersect at a predetermined angle. The convex portion 69 is formed in a rhomboid closed region surrounded by the concave portion 69.

  The top part P of the convex part 69 is a top part formed on the uneven surface 51 of the nonwoven fabric by the thick part 59. In the nonwoven fabric 20, as described above, the hydrophilicity of the thin portion 58 and the portion on the flat surface 52 side (the portion of the second layer 2) is higher than that of the top portion P. Thereby, when a liquid enters from the uneven surface 51 side, the liquid easily escapes to the flat surface 52 side, and the remaining liquid in the nonwoven fabric 20 decreases. Further, it is preferable that the hydrophilicity gradually increases from the top portion P of the thick portion 59 toward the thin portion (embossed portion) 58 and the portion on the flat surface 52 side (the portion of the second layer 2).

  Further, the second layer 2 on the flat surface 52 side of the thick portion 59 and the thin portion 58 has a distance between fibers of 90 μm or less, so that the liquid concealing property is high. Thereby, when excreted fluid such as menstrual blood is allowed to pass through, the redness is concealed from the uneven surface 51, and the brightness (L value) of the nonwoven fabric 20 is recognized more strongly. Thereby, the impression that the nonwoven fabric 20 has a clean feeling can be given. Moreover, when the nonwoven fabric 20 is incorporated in an absorbent article, the high absorbent performance of the article can be appropriately felt.

  Furthermore, the bulkiness recovery property of the convex part 69 is good because the 1st layer 1 which makes the uneven surface 51 consists of cotton blend of a heat | fever extensible fiber and a non-heat extensible heat-fusible fiber. Thereby, even if there exists a load, the convex part 69 of the uneven surface 51 is easy to be recovered, and the interfiber distance which brings about bulkiness is also maintained. As a result, the liquid drawability of the uneven surface 51 which is the liquid receiving surface is excellent, the liquid can be quickly delivered to the flat surface 52 side without liquid flow, and the remaining liquid can be suppressed. This further enhances the concealability of the liquid of the nonwoven fabric 20.

  The concavo-convex surface 51 of the nonwoven fabric 1 is directed to the embossing roll side during embossing, and is directed to the side opposite to the net surface (breathable support) when hot air treatment is performed by an air-through method. It is the surface on the side that is directly sprayed. Therefore, when a heat-extensible conjugate fiber is used as the constituent fiber of the nonwoven fabric, the heat-extensible conjugate fiber extends more greatly on the uneven surface 51 than on the flat surface 52. Therefore, the fiber diameter in the surface of the flat surface 52 becomes larger than the fiber diameter in the surface of the uneven surface 51 in the heat-extensible composite fiber. Further, the hydrophilicity of the thick portion 59 is lower on the uneven surface 51 side than on the flat surface 52 side.

  In the production of the nonwoven fabric 20, the temperature applied to the web during embossing is from the viewpoint of suppressing changes in the hydrophilicity in either the embossed part and its vicinity (peripheral part) or the embossed part and its vicinity (peripheral part). It is preferable that the temperature is 20 ° C. or more lower than the melting point of the polyethylene resin constituting the sheath part and less than the melting point of the resin component constituting the core part. On the other hand, the temperature applied during the hot air treatment is at least 10 ° C. lower than the melting point of the polyethylene resin, in particular, more than the melting point of the polyethylene resin, and more preferably the melting point of the polyethylene resin +5 from the viewpoint of surely causing a change in hydrophilicity. It is preferable that the temperature is not lower than ° C.

When the nonwoven fabric is used as, for example, a surface sheet of an absorbent article, the basis weight is preferably 10 g / m ² or more and 80 g / m ² or less, particularly preferably 15 g / m ² or more and 60 g / m ² or less. When used for the same application, the thickness of the convex portion 69 (thick portion 59) in the nonwoven fabric 1 is 0.5 mm or more and 3 mm or less, particularly 0.7 mm or more and 3 mm or less in the state after bulk recovery by hot air. preferable. On the other hand, the thickness of the recess 68 (thin portion 58) is preferably 0.01 mm or more and 0.4 mm or less, particularly preferably 0.02 mm or more and 0.2 mm or less. The thickness of the recess 68 is not substantially changed before and after the hot air is blown. The thickness of the convex part 69 and the concave part 68 is measured by observing the longitudinal section of the nonwoven fabric 20. First, the nonwoven fabric is cut into a size of 100 mm × 100 mm, and a measurement piece is collected. A plate of 12.5 g (diameter 56.4 mm) is placed on the measurement piece, and a load of 49 Pa is applied. Under this condition, the longitudinal section of the nonwoven fabric is observed with a microscope (VHX-1000, manufactured by Keyence Corporation), and the thicknesses of the convex portions 69 and the concave portions 68 are measured. In addition, when the convex part (thick part) and the concave part (thin part) are formed in the nonwoven fabric, the “thickness of the nonwoven fabric” refers to the thickness of the convex part (thick part).

The area ratio between the recesses 68 and the protrusions 69 in the nonwoven fabric 1 is expressed by an embossing rate (embossed area ratio, that is, the ratio of the total area of the recesses with respect to the entire nonwoven fabric 1), and affects the bulkiness and strength of the nonwoven fabric 1. give. From these viewpoints, the embossing rate in the nonwoven fabric 1 is preferably 5% to 35%, particularly preferably 10% to 25%. The embossing rate is measured by the following method. First, using a microscope (manufactured by Keyence Co., Ltd., VHX-1000), obtain a surface enlarged photograph of the nonwoven fabric 1, adjust the scale to this surface enlarged photograph, and measure the dimensions of the embossed part in the entire area T of the measurement part, An embossed area U is calculated.
The embossing rate can be calculated by the formula (U / T) × 100.

(Method for producing nonwoven fabric 10 and nonwoven fabric 20)
FIG. 5 shows a manufacturing apparatus suitably used for manufacturing the nonwoven fabric 10 and the nonwoven fabric 20 described above. The manufacturing apparatus 100 shown in the figure includes a first web manufacturing unit 110, a second web manufacturing unit 120, an embossing unit 130, an air-through processing unit 140, a calendar unit 150, and a winding unit 160.

  Both the first web manufacturing unit 110 and the second web manufacturing unit 120 are constituted by a card machine. The 1st web manufacture part 110 is a site | part which manufactures the web corresponding to the 1st layer 1 in the target nonwoven fabric. On the other hand, the 2nd web manufacture part 120 is a site | part which manufactures the web corresponding to the 2nd layer 2 in the target nonwoven fabric. The first web production unit 110 and the second web production unit 120 are supplied with appropriate raw material fibers according to the specific use of the target air-through nonwoven fabric, and the first web 111 and the second web 122 are produced. . An appropriate amount of fiber treatment agent is attached to the raw fiber according to the specific use of the target air-through nonwoven fabric.

The first web 111 and the second web 122 fed from the first web manufacturing unit 110 and the second web manufacturing unit 120 are overlapped at the embossing unit 130 and embossed. At this time, the webs 111 and 122 are overlapped so that the first web 111 is arranged on the second web 122. The embossed portion 130 can be composed of, for example, an uneven roll 131 and an anvil roll 132. The embossing conditions in the embossed part 130 may be any conditions as long as the constituent fibers of both webs 111 and 122 are pressed under heating to form an embossed fused part (not shown). Moreover, when using a heat | fever extensible fiber as a heat-fusion fiber, it is preferable to give an embossing process on the temperature conditions which this heat | fever extensible fiber extends | stretches.
This embossing is an optional process. For example, it is used when a plurality of convex portions are formed on the surface (one side or both sides) using the thermal extension of the heat-extensible fiber. In particular, this is a process necessary when manufacturing the above-described nonwoven fabric 20. As the uneven roll 131 when the nonwoven fabric 20 is manufactured, a roll having embossed convex portions in a lattice pattern matching the arrangement of the first linear concave portions 68A and the second linear concave portions 68B is used. It is done. Therefore, it is not necessary to manufacture the nonwoven fabric 10.

  The overlapping web 101 formed by integrating the two webs 111 and 122 in the embossed section 130 is conveyed to the air-through processing section 140. The air-through processing unit 140 has a sealed chamber 141. A circulating endless belt 142 is disposed in the chamber 141. The endless belt 142 is made of a breathable material, for example, a metal wire mesh belt. The overlapping web 101 is placed on the endless belt 142 and conveyed. Inside the chamber 141, there is provided a blowout port (not shown) for air heated to a predetermined temperature (hereinafter also referred to as “hot air”). Furthermore, a suction port (not shown) for blowing hot air is also provided in the chamber 141. While the overlapping web 101 conveyed into the chamber 141 passes through the chamber 141, hot air is blown against the overlapping web 101 in an air-through manner. The hot air is blown from the first web 111 side of the overlapping web 101. The hot air blown is discharged from the second web 122 side of the overlapping web 101. For this purpose, the outlet (not shown) is arranged to face the first web 111 in the overlapping web 101, and the suction port (not shown) is the first web. It is arranged so as to face 122.

  As described above, in the heat-fusible fiber to which the fiber treatment agents S1 to S5 are attached, the degree of penetration of the fiber treatment agent into the fiber differs depending on the amount of heat received by the heat-fusible fiber. To do. The greater the degree of penetration of the fiber treatment agent, the lower the hydrophilicity of the fiber compared to the initial state where the fiber treatment agent is adhered. In this production method, this phenomenon is used to generate a hydrophilicity gradient in the target air-through nonwoven fabric.

  Specifically, according to the air-through method, the fiber existing on the hot air blowing surface receives the largest amount of heat, and the fiber existing on the opposite side of the hot air blowing surface, that is, the surface facing the endless belt 142 receives the smallest amount of heat. It becomes like this. Therefore, in this manufacturing method, the fiber existing on the surface of the first web 111 in the overlapping web 101 receives the largest amount of heat, and the fiber existing on the surface of the second web 122 receives the smallest amount of heat. As a result, in the overlapping web 101, the degree of penetration of the fiber treatment agent into the fibers from the first web 111 side toward the second web 122 side decreases. Due to this, in the overlapping web 101, the hydrophilicity increases from the first web 111 side toward the second web 122 side.

  In the production of the nonwoven fabric 20, the temperature applied to the web during embossing is kept below the melting point of the resin constituting the sheath portion of the heat-fusible core-sheath composite fiber. In the subsequent hot air treatment, a temperature not lower than the melting point of the resin and not higher than the melting point of the resin component in the core is applied. At the time of this embossing, the air permeability decreases as the compression becomes closer to the embossed portion of the web. On the other hand, the polyethylene resin constituting the embossed portion only needs to be melted by pressure and can be minimized. On the other hand, at the time of hot air treatment, the hydrophilicity is unlikely to decrease because the portion (embossed portion) consolidated by embossing has little or no amount of hot air passing through. The closer to the top of the thick part (the part of reference numeral 59 in the nonwoven fabric 2) other than the embossed part, the easier the hot air passes through and the lower the hydrophilicity. Thereby, either the thin part formed by embossing (the part indicated by reference numeral 58 in the nonwoven fabric 2) and its peripheral part, or the thin part and its peripheral part become a hydrophilic part, and the other thick part. As the portion gets closer, the nonwoven fabric becomes relatively hydrophobic, and a nonwoven fabric is obtained in which the vicinity of the thickest portion 59 is a portion showing the maximum hydrophobicity. Moreover, by the said hot air process, melting | fusing of the sheath part of parts other than an embossing part advances, the intersection of a fiber is heat-seal | fused, and a strong nonwoven fabric is obtained.

In the non-woven fabric 10 and the non-woven fabric 20, in order to achieve the above-described (specific example of hydrophilicity gradient), the type and amount of the fiber treatment agent to be adhered to each heat-fusible fiber, the hot air blowing conditions in the air-through treatment section It can be controlled by (temperature of hot air, air volume, etc.).
For example, a fiber treatment agent containing components (A), (B), and (D) is applied to the fiber treatment agent on the first layer 1 side, and a component (A ), (B), and (C) to give a fiber treatment agent, the hydrophilicity on the second layer 2 side is higher than that on the first layer 1 side, and a hydrophilicity gradient can be given in the nonwoven fabric. It becomes possible.

  In the above method, the hydrophilicity gradient is expressed by partially reducing the hydrophilicity of the heat-fusible fiber to which the fiber treatment agent has been applied in the thickness direction of the nonwoven fabric by applying heat. Therefore, according to the above method, it is not necessary to overlap a plurality of nonwoven fabrics to provide a gradient in hydrophilicity, and it is possible to provide a gradient in hydrophilicity along the thickness direction of one single nonwoven fabric.

  The obtained non-woven fabric is introduced into the calendar unit 150 after coming out of the air-through processing unit 140 and subjected to calendar processing. By the calendering process, the surface of the air-through nonwoven fabric 102 becomes smooth, and fuzzing and the like are reduced. Thereafter, the nonwoven fabric is wound up in the winding unit 160. Moreover, you may give a secondary process after that. Examples of secondary processing include known three-dimensional shaping.

As mentioned above, the manufacturing method of the nonwoven fabric of this invention is not restrict | limited to embodiment mentioned above. For example, when the embossed portion is formed on the nonwoven fabric, the embossed portion forming pattern can be an arbitrary pattern such as a multi-row stripe shape, a dot shape, a checkered shape, or a spiral shape instead of the lattice shape. The shape of each point in the case of a dot shape may be a circle, an ellipse, a triangle, a quadrangle, a hexagon, a heart shape, or an arbitrary shape. Moreover, you may employ | adopt the shape which makes a square or rectangular lattice shape, or a tortoiseshell pattern.
Moreover, when embossing is performed, an embossing roll and a flat roll, or one of the rolls may be heated to produce a nonwoven fabric in which the embossed part and its periphery, or the embossed part and its surroundings have reduced hydrophilicity. it can. In addition, when the nonwoven fabric of the present invention is used for diapers, napkins, wipers, and other products, heat is applied to a desired portion at any time before production, during production, and after product formation. Thus, the hydrophilicity of some or all of the nonwoven fabrics of the present invention can be lowered, or water repellency can be achieved.

Moreover, if the manufacturing method of the nonwoven fabric of this invention is a method which can form the gradient of the hydrophilicity by a heat | fever, it will not be limited to an air through method, Arbitrary methods can be employ | adopted.
For example, as a method for forming the web, in addition to the card method, for example, an airlaid method, a spunbond method or the like can be used. Further, the heat treatment for imparting a hydrophilicity gradient can be performed after the web is made into a non-woven fabric, in addition to the formation of the web. In this case, you may heat-process in the state which laminated | stacked two sheets of nonwoven fabric.
As a method of performing heat treatment only on one side, a method of contacting a roll heated to a temperature equal to or higher than the melting point of the resin of the sheath portion on only one side of the web or nonwoven fabric being conveyed, or on the back side of the web or nonwoven fabric being conveyed For example, there is a method of blowing hot air having a temperature equal to or higher than the melting point of the resin of the sheath portion on the surface side of the web or the nonwoven fabric after devising so that the hot air does not penetrate. The temperature of the heat treatment is also at least 10 degrees lower than the melting point of the resin of the sheath part, particularly at least the melting point of the resin of the sheath part, and more particularly, the resin of the sheath part from the viewpoint of surely causing a change in hydrophilicity It is preferable that it is more than melting | fusing point +5 degreeC.
As a web nonwoven fabric forming method, various known nonwoven fabric forming methods such as spunlace, needle punch, chemical bond, and dot-like embossing can be employed.

  The nonwoven fabric of the present invention can be applied to various fields by taking advantage of the gradient of hydrophilicity along the thickness direction. For example, a top sheet, a second sheet (a sheet disposed between the top sheet and the absorbent body) in an absorbent article used to absorb liquid discharged from the body such as sanitary napkins, panty liners, disposable diapers, and incontinence pads , A back sheet, a leak-proof sheet, or a personal wipe sheet, a skin care sheet, and an objective wiper. When using the nonwoven fabric of this invention as a surface sheet or a second sheet of an absorbent article, it is preferable to use the 1st layer side of this nonwoven fabric as a skin opposing surface side.

The basis weight of the web used for producing the nonwoven fabric of the present invention is selected in an appropriate range depending on the specific use of the intended nonwoven fabric. The basis weight of the nonwoven fabric finally obtained is preferably 10 g / m ² or more and 80 g / m ² or less, and particularly preferably 15 g / m ² or more and 60 g / m ² or less.

  An absorbent article used for absorbing liquid discharged from the body typically includes a top sheet, a back sheet, and a liquid-retaining absorbent body interposed between both sheets. As the absorbent body and the back sheet when the nonwoven fabric according to the present invention is used as a top sheet, materials usually used in the technical field can be used without particular limitation. For example, as the absorbent body, a fiber assembly made of a fiber material such as pulp fiber or a fiber assembly in which an absorbent polymer is held can be coated with a covering sheet such as tissue paper or nonwoven fabric. As the back sheet, a liquid-impermeable or water-repellent sheet such as a thermoplastic resin film or a laminate of the film and a nonwoven fabric can be used. The back sheet may have water vapor permeability. The absorbent article may further include various members according to specific uses of the absorbent article. Such members are known to those skilled in the art. For example, when applying an absorbent article to a disposable diaper or a sanitary napkin, a pair or two or more pairs of three-dimensional guards can be disposed on the left and right sides of the topsheet.

  This invention discloses the following nonwoven fabrics and absorbent articles further regarding embodiment mentioned above.

<1>
A non-woven fabric having at least two layers, wherein the layer on one side of the non-woven fabric has a heat-fusible fiber having a fiber-to-fiber distance of 90 μm or less, and a fiber treating agent attached thereto, A nonwoven fabric containing A) a polyorganosiloxane, (B) a phosphate ester type anionic surfactant, and (C) an alkylhydroxysulfobetaine.

<2>
The non-woven fabric according to <1>, wherein the inter-fiber distance of the layer on the one surface side is more preferably 80 μm or less, further preferably 70 μm or less, preferably 50 μm or more, more preferably 55 μm or more, and further preferably 60 μm or more. .
<3>
The nonwoven fabric according to <1> or <2>, wherein the polyorganosiloxane as the component (A) is at least one selected from the group consisting of polydimethylsiloxane, polydiethylsiloxane, and polydipropylsiloxane.
<4>
<1> to <3>, wherein the polyorganosiloxane as the component (A) is contained in a ratio of 1% by mass to 30% by mass with respect to the total mass of the fiber treatment agent. Non-woven fabric.
<5>
<1> to <1> in which the phosphate ester type anionic surfactant as the component (B) is at least one selected from the group consisting of alkyl ether phosphates, dialkyl phosphates and alkyl phosphates. The nonwoven fabric according to any one of 4>.
<6>
The phosphoric acid ester type anionic surfactant as the component (B) comprises an alkyl ether phosphate, and the alkyl ether phosphate is a complete mono- or dialkyl phosphate having 16 to 18 carbon chains. The nonwoven fabric according to <5>, which is a neutralized or partially neutralized salt.
<7>
The content ratio of the component (B) in the fiber treatment agent attached to the heat-sealing fiber of the layer on the one surface side is preferably 5% by mass or more, more preferably 10% by mass or more, preferably The nonwoven fabric according to any one of <1> to <6>, which is 30% by mass or less, more preferably 25% by mass or less.
<8>
<1> to <1> wherein the alkylhydroxysulfobetaine as the component (C) is at least one selected from the group consisting of laurylhydroxysulfobetaine, myristylhydroxysulfobetaine, palmitylhydroxysulfobetaine and stearylhydroxysulfobetaine. The nonwoven fabric according to any one of 7>.
<9>
The alkyl sulfobetaine as the component (C) is contained in a proportion of less than 10% by mass, more preferably in a proportion of less than 9% by mass, and even more preferably in a proportion of less than 8% by mass, based on the total mass of the fiber treatment agent The non-woven fabric <10> according to any one of the above <1> to <8>, which is preferably contained in a proportion of 3% by mass or more, more preferably 5% by mass or more.
The content ratio of the component (A) and the component (C) is 1: 1.6 to 1: 0.6 by mass ratio, more preferably 1: 1.3 to 1: 0.9. The nonwoven fabric according to any one of <1> to <9>.
<11>
<1> to <10, wherein the content ratio of the component (A) to the component (B) is 1: 5 to 10: 1 by mass ratio, more preferably 1: 2 to 3: 1. > Any one of>.
<12>
The fiber treatment agent further has an alkyl phosphate having 6 to 22 carbon atoms, particularly 8 to 22 carbon atoms, an alkyl phosphate sodium salt, an alkyl ether phosphate sodium salt, a dialkyl phosphate sodium salt, a dialkyl sulfosuccinate sodium salt, and an alkylbenzene sulfonate sodium salt. And at least one anionic surfactant selected from the group consisting of alkyl sulfonate sodium salt, alkyl sulfate sodium salt and secondary alkyl sulfate sodium salt, and other alkali metal salts thereof. 11> The nonwoven fabric according to any one of 11>.
<13>
The fiber treatment agent is further alkyl (or alkenyl) trimethylammonium halide, dialkyl (or alkenyl) dimethylammonium halide and alkyl (or alkenyl) pyridinium halide, and an alkyl group or alkenyl group having 6 to 18 carbon atoms in these compounds. Any one of the above <1> to <12>, which comprises at least one cationic surfactant selected from the group consisting of those having halogens, wherein the halogen in the halide compound is preferably chlorine or bromine The nonwoven fabric described.
<14>
The fiber treatment agent further contains a zwitterionic surfactant made of alkylbetaine, and the alkylbetaine is alkyl (1 to 30 carbon atoms) dimethylbetaine, alkyl (1 to 30 carbon atoms) amide alkyl ( 1 to 4 carbon atoms) dimethyl betaine, alkyl (1 to 30 carbon atoms) dihydroxyalkyl (1 to 30 carbon atoms) betaine, sulfobetaine-type amphoteric surfactant, betaine-type zwitterionic surfactant, alanine Type [alkyl (C1 or more and 30 or less) aminopropionic acid type, alkyl (C1 or more and 30 or less) iminodipropionic acid type, etc.] Amphoteric surfactant, glycine type such as alkylbetaine [alkyl (C1 or more) 30 or less) aminoacetic acid type and the like] amino acid type amphoteric surfactant such as amphoteric surfactant, alkyl Comprising at least one selected from the group consisting of amino acid type amphoteric surfactants such as the number 1 to 30) taurine-type carbon, the <1> to nonwoven fabric according to any one of <13>.
<15>
The fiber treatment agent is a polyalcohol fatty acid ester such as glycerin fatty acid ester, poly (preferably n = 2 to 10) glycerin fatty acid ester, sorbitan fatty acid ester (all preferably fatty acid having 8 to 60 carbon atoms). , Polyoxyalkylene (added mole number 2 to 20) alkyl (carbon number 8 to 22) amide, polyoxyalkylene (added mole number 2 to 20) alkyl (carbon number 8 to 22) ether, polyoxyalkylene The nonwoven fabric according to any one of <1> to <14>, comprising at least one nonionic surfactant selected from the group consisting of modified silicone and amino-modified silicone.
<16>
The layer on one side of the nonwoven fabric contains fibers of 2.0 dtex or less as a main component, more preferably 1.8 dtex or less, further preferably 1.5 dtex or less, and preferably 0.8 dtex or more. The nonwoven fabric according to any one of <1> to <15>, more preferably 0.0 dtex or more, and further preferably 1.2 dtex.

<17>
In any one of the above items <1> to <16>, wherein the layer on the surface side opposite to the one surface side of the nonwoven fabric is blended with heat stretchable fibers and non-heat stretchable heat-fusible fibers. The nonwoven fabric described.

<18>
The nonwoven fabric according to any one of <1> to <17>, wherein the layer on the side opposite to the one surface side of the nonwoven fabric contains polyorganosiloxane.

（式中、Ｚはエステル基、アミド基、アミン基、ポリオキシアルキレン基、エーテル基若しくは２重結合を含んでいてもよい、炭素数１以上１２以下の直鎖又は分岐鎖のアルキル鎖を表わす。Ｒ^２及びＲ^３はそれぞれ独立に、エステル基、アミド基、ポリオキシアルキレン基、エーテル基若しくは２重結合を含んでいてもよい、炭素数２以上１６以下の直鎖又は分岐鎖のアルキル基を表わす。Ｘは―ＳＯ_３Ｍ、―ＯＳＯ_３Ｍ又は―ＣＯＯＭを表わし、ＭはＨ、Ｎａ、Ｋ、Ｍｇ、Ｃａ又はアンモニウムを表わす。）
＜２０＞
前記一般式（ＩＩ）で表されるアニオン界面活性剤が、該式中のＸが−ＳＯ_３Ｍ、すなわち親水基がスルホ基又はその塩であり、ジアルキルスルホン酸又はそれらの塩がより好ましい、前記＜１９＞に記載の不織布。
＜２１＞
前記一般式（ＩＩ）で表されるアニオン界面活性剤が、該式中のＸが−ＯＳＯ_３Ｍ、すなわち親水基がサルフェート基又はその塩であり、ジアルキル硫酸エステルがより好ましい、前記＜１９＞に記載の不織布。
＜２２＞
前記一般式（ＩＩ）で表されるアニオン界面活性剤が、該式中のＸが−ＣＯＯＭ、すなわち親水基がカルボキシ基又はその塩であり、ジアルキルカルボン酸がより好ましい、前記＜１９＞に記載の不織布。
＜２３＞
前記反対面側の層における繊維処理剤中の、前記成分（Ｄ）の含有割合は、好ましくは１質量％以上、より好ましくは５質量％以上であり、また、好ましくは２０質量％以下、より好ましくは１３質量％以下である、前記＜１９＞〜＜２２＞のいずれか１に記載の不織布。 <19>
Any one of the above <1> to <17>, wherein the layer on the opposite side to the one side of the nonwoven fabric contains the following components (A), (B) and (D) as a fiber treatment agent: The nonwoven fabric described.
(A) polyorganosiloxane,
(B) Phosphate ester type anionic surfactant,
(D) Anionic surfactant represented by the following general formula (II)

(In the formula, Z represents an ester group, an amide group, an amine group, a polyoxyalkylene group, an ether group or a linear or branched alkyl chain having 1 to 12 carbon atoms, which may contain a double bond. R ² and R ³ are each independently an ester group, an amide group, a polyoxyalkylene group, an ether group or a linear or branched alkyl group having 2 to 16 carbon atoms, which may contain a double bond. X represents —SO ₃ M, —OSO ₃ M or —COOM, and M represents H, Na, K, Mg, Ca or ammonium.)
<20>
In the anionic surfactant represented by the general formula (II), X in the formula is —SO ₃ M, that is, the hydrophilic group is a sulfo group or a salt thereof, and a dialkylsulfonic acid or a salt thereof is more preferable. The nonwoven fabric as described in said <19>.
<21>
<19> In the anionic surfactant represented by the general formula (II), X is —OSO ₃ M, that is, the hydrophilic group is a sulfate group or a salt thereof, and a dialkyl sulfate is more preferable. The nonwoven fabric described in 1.
<22>
In the anionic surfactant represented by the general formula (II), X in the formula is —COOM, that is, the hydrophilic group is a carboxy group or a salt thereof, and a dialkyl carboxylic acid is more preferable. Non-woven fabric.
<23>
The content ratio of the component (D) in the fiber treatment agent in the layer on the opposite side is preferably 1% by mass or more, more preferably 5% by mass or more, and preferably 20% by mass or less. The nonwoven fabric according to any one of <19> to <22>, preferably 13% by mass or less.

<24>
The nonwoven fabric according to any one of <1> to <17>, wherein the layer on the opposite surface side to the one surface side of the nonwoven fabric contains the following components (A), (B), and (E).
(A) polyorganosiloxane,
(B) Phosphate ester type anionic surfactant,
(E) Polyoxyalkylene-modified polyhydric alcohol fatty acid ester <25>
The nonwoven fabric according to <24>, wherein the polyhydric alcohol fatty acid ester constituting the component (E) is castor oil (hardened castor oil).
<26>
The polyhydric alcohol fatty acid ester constituting the component (E) is preferably composed of a polyoxyethylene (POE) -modified polyhydric alcohol fatty acid ester in which the alkylene oxide added to the polyhydric alcohol fatty acid ester is ethylene oxide. The nonwoven fabric according to <24>, particularly preferably composed of POE-modified castor oil (POE-modified cured castor oil), wherein the ester is castor oil (cured castor oil).
<27>
The content ratio of the component (E) in the fiber treatment agent in the layer on the opposite side is preferably 5% by mass or more, more preferably 10% by mass or more, with respect to the total mass of the fiber treatment agent. The non-woven fabric according to any one of <24> to <26>, preferably 20% by mass or less, more preferably 15% by mass or less, based on the total mass of the fiber treatment agent.

（式中、Ｚはエステル基、アミド基、アミン基、ポリオキシアルキレン基、エーテル基若しくは２重結合を含んでいてもよい、炭素数１以上１２以下の直鎖又は分岐鎖のアルキル鎖を表わす。Ｒ^２及びＲ^３はそれぞれ独立に、エステル基、アミド基、ポリオキシアルキレン基、エーテル基若しくは２重結合を含んでいてもよい、炭素数２以上１６以下の直鎖又は分岐鎖のアルキル基を表わす。Ｘは―ＳＯ_３Ｍ、―ＯＳＯ_３Ｍ又は―ＣＯＯＭを表わし、ＭはＨ、Ｎａ、Ｋ、Ｍｇ、Ｃａ又はアンモニウムを表わす。）
＜２９＞
前記一方の面側の層及びその反対側の層それぞれにおいて、繊維処理剤の熱融着繊維への付着量は、該繊維処理剤を除く熱融着性繊維の全質量に対する割合として、０．１質量％以上が好ましく、０．２質量％以上がより好ましく、０．３質量％以上がさらに好ましく、また、１．５質量％以下が好ましく、１．０質量％以下がより好ましく、０．５質量％以下がさらに好ましい、前記＜１＞〜＜２８＞のいずれか１に記載の不織布。
＜３０＞
前記熱融着性繊維に酸化チタンが含有されており、該熱融着性繊維に含有させる酸化チタンの量は、繊維の全質量に対して、好ましくは０．５質量％以上、より好ましくは１質量％以上であり、好ましくは５質量％以下、より好ましくは４．５質量％以下である、前記＜１＞〜＜２９＞のいずれか１に記載の不織布。
＜３１＞
前記不織布が、一方の面側からその反対面へ向かって親水度が高くなるように親水度勾配を有している前記＜１＞〜＜３０＞のいずれか１に記載の不織布。
＜３２＞
前記＜１＞〜＜３１＞のいずれか１に記載の不織布を用いた吸収性物品。 <28>
The non-woven fabric according to any one of <1> to <17>, wherein the layer on the side opposite to the one side contains the following components (A), (B), (D) and (E): .
(A) polyorganosiloxane,
(B) Phosphate ester type anionic surfactant,
(E) Polyoxyalkylene-modified polyhydric alcohol fatty acid ester (D) Anionic surfactant represented by the following general formula (II)

(In the formula, Z represents an ester group, an amide group, an amine group, a polyoxyalkylene group, an ether group or a linear or branched alkyl chain having 1 to 12 carbon atoms, which may contain a double bond. R ² and R ³ are each independently an ester group, an amide group, a polyoxyalkylene group, an ether group or a linear or branched alkyl group having 2 to 16 carbon atoms, which may contain a double bond. X represents —SO ₃ M, —OSO ₃ M or —COOM, and M represents H, Na, K, Mg, Ca or ammonium.)
<29>
In each of the layer on the one surface side and the layer on the opposite side, the adhesion amount of the fiber treatment agent to the heat-fusible fiber is 0. 1 mass% or more is preferable, 0.2 mass% or more is more preferable, 0.3 mass% or more is more preferable, 1.5 mass% or less is preferable, 1.0 mass% or less is more preferable, The nonwoven fabric according to any one of <1> to <28>, further preferably 5% by mass or less.
<30>
The heat-fusible fiber contains titanium oxide, and the amount of titanium oxide to be contained in the heat-fusible fiber is preferably 0.5% by mass or more, more preferably based on the total mass of the fiber. The nonwoven fabric according to any one of <1> to <29>, which is 1% by mass or more, preferably 5% by mass or less, and more preferably 4.5% by mass or less.
<31>
The nonwoven fabric according to any one of <1> to <30>, wherein the nonwoven fabric has a hydrophilicity gradient so that the hydrophilicity increases from one surface side toward the opposite surface.
<32>
An absorbent article using the nonwoven fabric according to any one of <1> to <31>.

EXAMPLES Hereinafter, although this invention is demonstrated in more detail based on an Example, this invention is limited to this and is not interpreted. In the examples, “part” and “%” are based on mass unless otherwise specified. In the above description, the “layer on one side” is hereinafter referred to as “first layer”, and the “layer on the opposite side” is referred to as “second layer”. In Tables 1 to 3 below, “upper layer” means the first layer, and “lower layer” means the second layer.
Components (A) to (C) used the following agents in the examples.
Polydimethylsiloxane [the component (A), silicone “KM903” manufactured by Shin-Etsu Silicone Co., Ltd.]
Alkyl phosphate ester potassium salt [the component (B), manufactured by Kao Corporation, neutralized potassium hydroxide of gripper 4131 (trade name)]
・ Lauryl hydroxysulfobetaine [the above component (C), manufactured by Kao Corporation, Amphital 20HD (trade name)]
Dioctylsulfosuccinic acid [the above component (D), manufactured by Kao Corporation, Perex OT-P (trade name)]
・ Polyoxyethylene (POE) modified polyhydric alcohol fatty acid ester [the above component (E), manufactured by Kao Corporation, Emanon CH60 (trade name)]
Polyoxyethylene (POE) polyoxypropylene (POP) modified silicone [components other than the above components (A) to (E), manufactured by Shin-Etsu Chemical Co., Ltd., X-22-4515 (HLB5) (trade name)]
Polyoxyethylene (added mole number: 2) alkylamide [components (A) to (components other than CE, manufactured by Kawaken Fine Chemicals Co., Ltd., Amizole SDE (trade name)]
Alkyl (stearyl) betaine [components other than the above components (A) to (E), manufactured by Kao Corporation, Anhitoal 86B]
Polyoxyethylene sorbitan monolaurate [components other than the above components (A) to (E), manufactured by Kao Corporation, Rheodor TW-S120V]

Example 1
A non-woven fabric having a two-layer structure of a first layer and a second layer was produced using the manufacturing apparatus 100 shown in FIG. However, embossing was not performed. The first layer was obtained by blending a heat stretchable fiber having a fineness of 3.3 dtex and a non-heat stretchable heat-fusible fiber having a fineness of 2.2 dtex at a composition ratio of 50:50. The thickness of the first layer was 0.8 mm, and the basis weight was 15 g / m ² . The second layer was composed only of heat-fusible fibers having a fineness of 1.8 dtex. The thickness of the second layer was 0.8 mm and the basis weight was 15 g / m ² .
The fiber treatment agent adhered to the fibers of the first layer is composed of component (A): 5.0% by mass, component (B): 23.8% by mass, component (D): 9.5% by mass, and the rest. It was set as the structure which consists of an "other" component shown in Table 1. The adhesion amount of the fiber treatment agent was 0.39% by mass.
The fiber treatment agent adhered to the fibers of the second layer is component (A): 5.0% by mass, component (B): 23% by mass, component (C): 3.0% by mass, and component (D): The composition was 9.2% by mass, and the remainder was composed of “other” components shown in Table 1. The content ratio of component (A) to component (C) was 1: 0.6. The adhesion amount of the fiber treatment agent was 0.44% by mass.
Moreover, the distance between fibers was measured by the method mentioned above about the 1st layer and the 2nd layer. The inter-fiber distance of the first layer was 101 μm, and the inter-fiber distance of the second layer was 84 μm.

(Example 2)
The fiber treatment agent adhered to the fibers of the second layer is as follows: Component (A): 5.0% by mass, Component (B): 22.3% by mass, Component (C): 6.0% by mass, Component (D ): 8.9% by mass, and the remainder composed of “other” components shown in Table 1. The content ratio of component (A) to component (C) was 1: 1.2. The adhesion amount of the fiber treatment agent was 0.45% by mass. Otherwise, a nonwoven fabric was produced under the same conditions as in Example 1.

(Example 3)
The fiber treatment agent adhered to the fibers of the first layer does not contain the component (D), the component (A): 5.0% by mass, the component (B): 23.7% by mass, and the component (E): 10 0.0 mass%, and the rest was composed of “other” components shown in Table 1. Otherwise, a nonwoven fabric was produced under the same conditions as in Example 2.

Example 4
The fiber treatment agent adhered to the fibers of the first layer is component (A): 5.0% by mass, component (B): 21.3% by mass, component (D): 8.5% by mass, component (E ): 10.0% by mass, and the remainder composed of “other” components shown in Table 1. Otherwise, a nonwoven fabric was produced under the same conditions as in Example 2.

(Example 5)
The fineness of the fibers of the second layer was 1.2 dtex. Therefore, the distance between the fibers of the second layer was 69 μm. The fiber treatment agent components adhered to the fibers of the second layer are as follows: Component (A): 5.0% by mass, Component (B): 21.8% by mass, Component (C): 8.0% by mass, Component ( D): 8.7% by mass, and the remainder composed of “other” components shown in Table 1. The content ratio of component (A) to component (C) was 1: 1.6. The adhesion amount of the fiber treatment agent was 0.43% by mass. Otherwise, a nonwoven fabric was produced under the same conditions as in Example 1.

(Example 6)
The component configuration of the fiber treatment agent adhered to the fibers of the second layer and the amount of the fiber treatment agent attached were the same as those in Example 2. However, the content ratio of component (A) to component (C) was 1: 1.2. Otherwise, a nonwoven fabric was produced under the same conditions as in Example 1.

(Example 7)
The fiber treatment agent adhered to the fibers of the second layer is component (A): 5.0% by mass, component (B): 21.8% by mass, component (C): 8.0% by mass, component (D ): 8.7% by mass, and the remainder composed of “other” components shown in Table 1. The content ratio of component (A) to component (C) was 1: 1.6. The adhesion amount of the fiber treatment agent was 0.44% by mass. Otherwise, a nonwoven fabric was produced under the same conditions as in Example 1.

(Example 8)
The fiber treatment agent adhered to the fibers of the second layer is as follows: Component (A): 5.0% by mass, Component (B): 21.3%, Component (C): 10.0% by mass, Component (D) : 8.5% by mass, and the remainder composed of “other” components shown in Table 2. The content ratio of component (A) to component (C) was 1: 2. Otherwise, a nonwoven fabric was produced under the same conditions as in Example 1.

Example 9
The fiber treatment agent adhered to the fibers of the second layer is component (A): 10.0% by mass, component (B): 21.8% by mass, component (C): 5.0% by mass, component (D ): 8.7% by mass, and the remainder composed of “other” components shown in Table 2. The content ratio of component (A) to component (C) was 2: 1. The adhesion amount of the fiber treatment agent was 0.43% by mass. Otherwise, a nonwoven fabric was produced under the same conditions as in Example 1.

(Example 10)
The first layer was made of only heat-fusible fiber and the fineness was 2.2 dtex.
The fiber treatment agent adhered to the fibers of the second layer is as follows: Component (A): 5.0% by mass, Component (B): 22.3% by mass, Component (C): 6.0% by mass, Component (D ): 8.9% by mass, and the remainder composed of “other” components shown in Table 2. The content ratio of component (A) to component (C) was 1: 1.2. The adhesion amount of the fiber treatment agent was 0.45% by mass. Otherwise, a nonwoven fabric was produced under the same conditions as in Example 1.

(Example 11)
The fiber treatment agent adhered to the fibers of the first layer does not contain the component (A), the component (B): 25% by mass, the component (D): 10% by mass, and the rest is shown in Table 2. It was set as the structure which consists of these components. The adhesion amount of the fiber treatment agent was 0.42% by mass.
The component composition of the fiber treatment agent adhered to the fibers of the second layer, the content ratio of the component (A) and the component (C), and the amount of the fiber treatment agent attached were the same as those in Example 2.
Otherwise, a nonwoven fabric was produced under the same conditions as in Example 1.

(Example 12)
The fiber treatment agent adhered to the fibers of the first layer does not contain the component (D), the component (A): 5.0% by mass, the component (B): 26.4% by mass, and the rest in Table 2. It was set as the structure which consists of an "other" component shown.
The component composition of the fiber treatment agent adhered to the fibers of the second layer, the content ratio of the component (A) and the component (C), and the amount of the fiber treatment agent attached were the same as those in Example 2.
Otherwise, a nonwoven fabric was produced under the same conditions as in Example 1.

(Comparative Example 1)
The fiber treatment agent adhered to the fibers of the second layer does not contain the component (C), the component (A): 5.0% by mass, the component (B): 23.8% by mass, and the component (D): 9 The remaining amount was set to 5% by mass, and the remainder was composed of “other” components shown in Table 3. The adhesion amount of the fiber treatment agent was 0.39% by mass. Otherwise, a nonwoven fabric was produced under the same conditions as in Example 1.

(Comparative Example 2)
The fiber treatment agent adhered to the fibers of the second layer does not contain the component (C), the component (A): 5.0% by mass, the component (B): 21.3% by mass, and the component (D): 8 The remaining amount was set to 5% by mass, and the remainder was composed of “other” components shown in Table 3. The adhesion amount of the fiber treatment agent was 0.42% by mass. Otherwise, a nonwoven fabric was produced under the same conditions as in Example 1.

(Comparative Example 3)
The fiber treatment agent adhered to the fibers of the first layer does not contain the component (A), the component (B): 25% by mass, the component (D): 10% by mass, and the rest is shown in Table 1 as “Others”. It was set as the structure which consists of these components. The adhesion amount of the fiber treatment agent was 0.42% by mass.
The fiber treatment agent adhered to the fibers of the second layer does not contain the component (A) and the component (C), the component (B): 25% by mass, the component (D): 10% by mass, and the remainder is shown in Table 3. It was set as the structure which consists of an "others" component shown in. The adhesion amount of the fiber treatment agent was 0.45% by mass.
Otherwise, a nonwoven fabric was produced under the same conditions as in Example 1.

(Comparative Example 4)
The component configuration of the fiber treatment agent adhered to the fibers of the second layer and the amount of the fiber treatment agent attached were the same as those in Comparative Example 3. Otherwise, a nonwoven fabric was produced under the same conditions as in Example 1.

(Comparative Example 5)
A non-woven fabric consisting only of the first layer of Example 1 without the second layer was produced in the same manner as in Example 1.

(Comparative Example 6)
The fineness of the fibers of the second layer was 2.2 dtex. Therefore, the distance between the fibers of the second layer was 93 μm. The component configuration of the fiber treatment agent adhered to the fibers of the second layer was the same as that of Comparative Example 1. The adhesion amount of the fiber treatment agent was 0.43% by mass. Otherwise, a nonwoven fabric was produced under the same conditions as in Example 1.

(Comparative Example 7)
The fineness of the fibers of the second layer was 3.3 dtex. Therefore, the inter-fiber distance of the second layer was 114 μm. The component configuration of the fiber treatment agent adhered to the fibers of the second layer was the same as that of Comparative Example 1. The adhesion amount of the fiber treatment agent was 0.42% by mass. Otherwise, a nonwoven fabric was produced under the same conditions as in Example 1.

(Measurement of contact angle)
About the nonwoven fabric obtained in Examples 1-12 and Comparative Examples 1-7, the contact angle of the water with respect to a fiber was measured by the method mentioned above. The results are shown in Tables 1-3.
The fiber to be measured has a fiber length of 1 mm from each of the first layer first part, the first layer second part, the second layer first part and the second layer second part using precision scissors and tweezers. Cut and taken out from the nonwoven fabric. Moreover, when the 1st layer consisted of cotton blend of a heat | fever extensible fiber and a non-heat extensible heat-fusible fiber, each fiber was taken out.

(Nonwoven fabric concealment rate: red plate concealment rate)
The red plate concealment rate is determined by placing the attached standard plate (red) on the second surface 10B (surface with the second layer 2) of the nonwoven fabric obtained in Examples 1-12 and Comparative Examples 1-7. Thus, the measurement was performed.
First, the attached standard plate (with the red surface as the measurement surface) was measured using a simple spectral color difference meter NF333 manufactured by Nippon Denshoku Industries Co., Ltd. Among the obtained absorption wavelengths, 500 cm ⁻¹ was particularly selected, and the reflectance at this time was recorded (Ra). Next, remove the red plate, place the sample on the sample stage, and further so that the back surface of the sample (the surface opposite to the measurement surface, the second surface 10B (surface with the second layer 2) and the red surface of the red plate face each other. A red plate was placed, and the measurement was performed five times at different sites for one sample, and the average value (Rb) of the reflectance of 500 cm ⁻¹ was calculated.From the obtained Ra and Rb values, the red plate concealment rate was calculated. Was determined by the following equation (1).
Red plate concealment rate (%)
= [(Rb-Ra) / (100-Ra)] x 100 (1)
The higher the value obtained as a result of the above, the higher the performance of the non-woven fabric concealing, the improvement of whiteness after liquid absorption (L value), and the redness of the absorber as seen through the white surface material. And the whiteness (L value) transmitted from the absorber is improved.

(Evaluation)
The following evaluation removes a surface sheet from a sanitary napkin (manufactured by Kao Corporation: Laurie Speed + Skin Clean Guard, manufactured in 2013) as an example of an absorbent article. ) And a sanitary napkin for evaluation obtained by fixing the periphery thereof.

(Liquid remaining amount of surface sheet (nonwoven fabric specimen))
An acrylic plate having a transmission hole with an inner diameter of 1 cm is overlaid on the surface of each evaluation sanitary napkin, and a constant load of 100 Pa is applied to the napkin. Under such a load, 3.0 g of defibrinated horse blood is poured from the permeation hole of the acrylic plate. 120 seconds after pouring the defibrillated horse blood, 3.0 g of defibrillated horse blood (adjusted to 8.0 cP of equine defibrinated blood manufactured by Japan Biotest Laboratories) is poured. Adjustment was performed under the condition of 30 rpm with a Toki Sangyo TVB10 viscometer. When the horse blood is allowed to stand, a high-viscosity part (such as red blood cells) precipitates, and a low-viscosity part (plasma) remains as a supernatant. The mixing ratio of the part was adjusted to 8.0 cP. The acrylic plate is removed 60 seconds after injecting a total of 6.0 g of defibrinated horse blood. Next, the weight (W2) of the nonwoven fabric test body is measured, and the difference (W2−W1) from the weight (W1) of the nonwoven fabric test body before pouring horse blood, which has been measured in advance, is calculated. The above operation is performed three times, and the average value of the three times is defined as the remaining liquid amount (mg). The liquid remaining amount is an index of how much the wearer's skin gets wet. The smaller the liquid remaining amount, the better the result.

(Evaluation of remaining liquid amount (wet back amount))
On the surface of each sanitary napkin for evaluation, an acrylic plate having a perforation hole with an inner diameter of 1 cm was overlapped, and a constant load of 100 Pa was applied to the napkin. Under such a load, a total of 6.0 g of defibrinated horse blood is poured from the permeation hole of the acrylic plate every 3.0 minutes. The acrylic plate was removed 300 seconds after pouring the horse blood, and then a tissue paper was placed on the surface of the nonwoven fabric, and a weight was placed on the tissue paper, and a load of 2000 Pa was applied to the napkin. . After 5 seconds from the stacking of the weight stones, the weight stones and the tissue paper are removed, the weight of the tissue paper (W4) is measured, and the weight of the tissue paper before being stacked on the surface of the nonwoven fabric (W3) measured in advance. ) (W4-W3) was calculated. The above operation is performed three times, and the average value of the three times is defined as the liquid return amount (mg). The smaller the wetback amount, the less likely the liquid return occurs and the higher the evaluation. The results are shown in Tables 1-3.

(Measurement of L value of nonwoven fabric specimen; measurement of concealment)
About the sanitary napkin for each said evaluation, L value of the surface sheet (nonwoven fabric test body) surface was measured. Specifically, using a simplified spectral color difference meter NF333 manufactured by Nippon Denshoku Industries Co., Ltd., L values were measured at the position where defibrinated horse blood was introduced and at the periphery thereof. The former measured the L value (lightness) of the part where the redness of the topsheet and the redness of the absorber overlap. The latter measured L value about the part which has no redness of a surface sheet, and the part which has redness of an absorber using the above-mentioned spectral color difference meter. The L value was measured when 30 g had passed after 3.0 g of defibrinated horse blood was poured in through 3.0 g from the perforation hole of the acrylic plate.
In Tables 1 to 3, the former numerical value is simply shown in the “whiteness (L value)” column, and the latter numerical value is shown in the “L value transmitted from the absorber” column. That is, “whiteness” indicates the redness hiding property of the top sheet itself and the absorber, and “value transmitted from the absorber” indicates the redness hiding property of the absorber.
L value (lightness) indicates that the larger the value, the closer the color is to white, and the less redness is visible on the top sheet (nonwoven fabric test body). That is, the concealment property is high. If the “whiteness” was 65 or more and the “L value permeated from the absorber” was 75 or more, it was determined to be acceptable as showing high performance as a non-woven fabric hiding property.

(Sensory evaluation: Evaluation of absorbency)
Similar to the evaluation of the remaining liquid, after putting 6.0 g of defibrinated horse blood, put the sample after 30 minutes on a flat table, and just determine the appearance after absorption according to the following three criteria. did. The results were obtained with 10 monitors (adult women in their 20s to 40s) as subjects, and the results were shown as an average.
Judgment criteria 3: It looks white and feels good absorbency.
2: Appears red and slightly absorbs.
1: Appearance is reddish and absorbability is poor.

As shown in Tables 1 to 3, Examples 1 to 12 had a liquid remaining amount and a liquid return amount that were smaller than those of Comparative Examples 1 to 4, although the interfiber distance was reduced to the same extent as Comparative Examples 1 to 4. It was kept low. This is because Examples 1 to 12 had the hydrophilicity increased by attaching components (A) to (C). On the other hand, in Comparative Examples 1 and 2, the component (C) was not adhered to the second layer, so that the hydrophilicity of the first portion of the second layer did not increase (if the contact angle value was small). Rather, it was in the direction of making it relatively hydrophobic with respect to the first part of the first layer. Therefore, a preferable hydrophilicity gradient did not appear, and the liquid remaining amount and the liquid return amount remained high. That is, the high degree of hydrophilicity of the first part of the second layer relative to the first part of the first layer tends to reduce the remaining amount of liquid. This is particularly true for Examples 1 to 5, 11, 12, and Comparative Example 1. It can be confirmed from the comparison of two. Further, in Comparative Examples 3 and 4, since the component (A) was not adhered to the second layer, a preferable hydrophilicity gradient did not appear between the first part and the second part of the second layer, and the liquid remained. The volume and liquid return remained high.
In addition, as can be seen from a comparison between Examples 7 and 8 and Examples 1 to 5, when the amount of hydroxysulfobetaine added to the second layer is increased, the hydrophilicity is increased and the first portion of the second layer is increased. The hydrophilicity gradient becomes smaller between the first portion and the second portion, and an increase in the remaining amount of liquid can be confirmed. For this reason, it is preferable to impart a hydrophilicity gradient to the entire nonwoven fabric while increasing the hydrophilicity, which leads to higher performance.
Further, in Examples 1 to 12, the inter-fiber distance of the second layer was made smaller than those of Comparative Examples 6 and 7, and “Whiteness (L value)” and “L value transmitted from the absorber” were Comparative Example 6. And higher than 7. That is, the concealability was higher than those of Comparative Examples 6 and 7. In addition, in the “sensory evaluation” of absorbency, Examples 1 to 12 were determined to have better absorbability than Comparative Examples 6 and 7. On the other hand, with respect to the liquid remaining amount and the liquid return amount, Examples 1 to 12 were suppressed to the same level or lower than those of Comparative Examples 6 and 7 having a larger interfiber distance.
In addition, Examples 1 to 12 have better three results of “whiteness (L value)”, “L value transmitted from the absorber” and “sensory evaluation” than Comparative Example 5 having only the first layer. Met.

10 Non-woven fabric 10A First surface 10B (of non-woven fabric) Second surface 1 (first layer) First layer 1A (First layer) First surface 1B (Second layer) Second surface 2 Second layer 2A (Second First side 2B (of layer) second side (of second layer)

Claims (11)

  A non-woven fabric having at least two layers, wherein the layer on one side of the non-woven fabric has a heat-fusible fiber having a fiber-to-fiber distance of 90 μm or less, and a fiber treating agent attached thereto, A nonwoven fabric containing A) a polyorganosiloxane, (B) a phosphate ester type anionic surfactant, and (C) an alkylhydroxysulfobetaine.   The nonwoven fabric according to claim 1, wherein the polyorganosiloxane as the component (A) is contained in a proportion of 1% by mass or more and 30% by mass or less with respect to the total mass of the fiber treatment agent.   The nonwoven fabric according to claim 1 or 2, wherein a content ratio of the component (A) to the component (C) is from 1: 1.6 to 1: 0.6 by mass ratio.   The nonwoven fabric of any one of Claims 1-3 which contains the alkyl sulfo betaine which is the said component (C) in the ratio of less than 10 mass% with respect to the total mass of a fiber processing agent.   The nonwoven fabric of any one of Claims 1-4 in which the layer of the one surface side of the said nonwoven fabric contains a 2.0 dtex or less fiber as a main component.   The layer of the surface side opposite to the one surface side of the said nonwoven fabric is a cotton blend with a heat | fever extensible fiber and a non-heat extensible heat-fusible fiber. Non-woven fabric.   The nonwoven fabric according to any one of claims 1 to 6, wherein the layer on the opposite surface side to the one surface side of the nonwoven fabric contains polyorganosiloxane. 7. The layer according to claim 1, wherein the layer on the opposite side to the one side of the nonwoven fabric contains the following components (A), (B) and (D) as a fiber treatment agent. Non-woven fabric.
(A) polyorganosiloxane,
(B) Phosphate ester type anionic surfactant,
(D) Anionic surfactant represented by the following general formula (II)

(In the formula, Z represents an ester group, an amide group, an amine group, a polyoxyalkylene group, an ether group or a linear or branched alkyl chain having 1 to 12 carbon atoms, which may contain a double bond. R ² and R ³ are each independently an ester group, an amide group, a polyoxyalkylene group, an ether group or a linear or branched alkyl group having 2 to 16 carbon atoms, which may contain a double bond. X represents —SO ₃ M, —OSO ₃ M or —COOM, and M represents H, Na, K, Mg, Ca or ammonium.) The non-woven fabric according to any one of claims 1 to 6, wherein the layer on the one surface side and the opposite surface side of the non-woven fabric contains the following components (A), (B) and (E).
(A) polyorganosiloxane,
(B) Phosphate ester type anionic surfactant,
(E) Polyoxyalkylene-modified polyhydric alcohol fatty acid ester The nonwoven fabric according to any one of claims 1 to 6, wherein the layer on the side opposite to the one side contains the following components (A), (B), (D) and (E).
(A) polyorganosiloxane,
(B) Phosphate ester type anionic surfactant,
(E) Polyoxyalkylene-modified polyhydric alcohol fatty acid ester (D) Anionic surfactant represented by the following general formula (II)

(In the formula, Z represents an ester group, an amide group, an amine group, a polyoxyalkylene group, an ether group or a linear or branched alkyl chain having 1 to 12 carbon atoms, which may contain a double bond. R ² and R ³ are each independently an ester group, an amide group, a polyoxyalkylene group, an ether group or a linear or branched alkyl group having 2 to 16 carbon atoms, which may contain a double bond. X represents —SO ₃ M, —OSO ₃ M or —COOM, and M represents H, Na, K, Mg, Ca or ammonium.) The absorbent article using the nonwoven fabric of any one of Claims 1-10.

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