WO2014171388A1

WO2014171388A1 - Nonwoven fabric and textile treating agent

Info

Publication number: WO2014171388A1
Application number: PCT/JP2014/060384
Authority: WO
Inventors: 裕太寒川; 舛木　哲也; 祥一種市; 真行湊崎
Original assignee: 花王株式会社
Priority date: 2013-04-19
Filing date: 2014-04-10
Publication date: 2014-10-23

Abstract

This nonwoven fabric uses a thermally adhesive textile to which a textile treating agent has adhered, the textile treating agent containing (A) a polyorganosiloxane, (B) an alkyl phosphate ester, and (C) an anionic surfactant represented by general formula (1). (In the formula: Z represents a straight-chain or branched-chain alkyl chain having a carbon number of 1 to 12, which may include an ester group, an amide group, an amine group, a polyoxyalkylene group, an ether group, or a double bond; R₁ and R₂ each independently represent a straight-chain or branched-chain alkyl group having a carbon number of 2 to 16, which may include an ester group, an amide group, a polyoxyalkylene group, an ether group, or a double bond; X represents -SO₃M, -OSO₃M, or -COOM; and M represents H, Na, K, Mg, Ca, or ammonium.)

Description

Nonwoven fabric and fiber treatment agent

The present invention relates to a nonwoven fabric and a fiber treatment agent.

The present applicant first heat-treated the core-sheath-type composite fiber having a hydrophilic agent attached to the surface thereof, and changed the hydrophilicity of the fiber, and the hydrophilicity was partially reduced using the technique. The technique which manufactures a nonwoven fabric was proposed (refer patent document 1). The technique of providing a hydrophilic gradient in the thickness direction of the nonwoven fabric is described not only in the same document but also in Patent Documents 2 and 3, for example.

By the way, what mixed the silicone type compound as a processing agent which processes a fiber is known, for example, in patent document 4, in order to prevent the sticking of the fiber at the time of manufacturing an elastic fiber, highly polymerized polymer The use of an oil agent composed of an organosiloxane and a base oil is described. Patent Document 5 describes the use of an oil containing a highly polymerized polyorganosiloxane for the purpose of maintaining the dryness of the nonwoven fabric surface even after contact with a liquid without inferior high-speed card properties. However, it is not described that the oil agent contains an alkyl sulfate ester salt or an alkyl sulfonate salt.

JP 2010-168715 A Japanese Patent Laying-Open No. 2005-87659 JP 2005-314825 A JP 2003-201678 A JP-A-5-51872

In Patent Document 1, it is indispensable to use a heat-extensible fiber, and other fibers are not assumed, and further improvement in the liquid residue on the surface has been desired. The techniques described in Patent Documents 2 and 3 also have been desired to further improve the liquid residue on the surface.

Further, the technique of Patent Document 4 is a technique for preventing sticking of elastic fibers, and there is no suggestion that the oil used in the same document is used for other than elastic fibers.

The present invention is a nonwoven fabric using heat-fusible fibers to which a fiber treatment agent is attached, wherein the fiber treatment agent comprises the following (A) component, (B) component, and (C) component nonwoven fabric. It is to provide.
(A) polyorganosiloxane,
(B) an alkyl phosphate ester,
(C) Anionic surfactant represented by the following general formula (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 ₁ and R ₂ 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. , X represents —SO ₃ M, —OSO ₃ M or —COOM, and M represents H, Na, K, Mg, Ca or ammonium.)

Moreover, this invention is an air through nonwoven fabric containing the heat-fusible fiber to which the fiber processing agent has adhered, Comprising: It has a 1st layer and a 2nd layer adjacent to this, A 1st layer and a 2nd layer The air-through nonwoven fabric NW1 or the air-through nonwoven fabric NW2 in which the heat-fusible fiber having the fiber treatment agent attached to at least one of them is provided.

The air-through nonwoven fabric NW1 satisfies the following condition I.
(Condition I)
The first layer is virtually divided into two in the thickness direction, and the part far from the second layer is the first layer first part among the two parts divided into two equal parts, and the side close to the second layer When the first layer second part is compared with the first layer first part, the first layer second part, and the second layer, the following (11) and (12) Meet relationships,
(11) The first layer second portion has a higher hydrophilicity than the first layer first portion.
(12) The hydrophilicity of any part of the second layer is higher than the second part of the first layer.
The said fiber processing agent contains said (A) component, (B) component, and (C) component.

The air-through nonwoven fabric NW2 satisfies the following condition II.
(Condition II)
The second layer is virtually divided into two in the thickness direction, and of the two divided parts, the part closer to the first layer is defined as the second layer first part, and the side far from the first layer When the second layer is the second part, the hydrophilicity of the first layer, the second layer first part, and the second layer second part is compared, and the following (21) and (22) Meet relationships,
(21) The hydrophilicity of the second layer first portion is higher than that of the first layer.
(22) The hydrophilicity of the second layer second portion is higher than that of the second layer first portion.
The said fiber processing agent contains said (A) component, (B) component, and (C) component.

Further, the present invention is a fiber treatment agent containing the following component (A), component (B) and component (C), wherein the content ratio of the component (A) to the component (C) (the former: The latter is a nonwoven fabric fiber treatment agent having a mass ratio of 1: 3 to 4: 1 and containing the component (A) in a proportion of 30% by mass or less based on the mass of the fiber treatment agent. Is.
(A) polyorganosiloxane,
(B) an alkyl phosphate ester,
(C) Anionic surfactant represented by the following general formula (1)

Fig.1 (a) is a perspective view which shows one Embodiment of the nonwoven fabric of this invention, FIG.1 (b) is a partially expanded view of the cross section along the thickness direction of the nonwoven fabric shown to Fig.1 (a). . FIG. 2 is a schematic view showing a process for producing a partially hydrophobized nonwoven fabric using heat hydrophobized fibers. FIG. 3 is a diagram schematically showing a cross-sectional structure of another embodiment of the nonwoven fabric of the present invention. FIG. 4 is a diagram schematically showing a cross-sectional structure of another embodiment of the nonwoven fabric of the present invention. FIG. 5 is a diagram schematically showing a cross-sectional structure of still another embodiment of the nonwoven fabric of the present invention. FIG. 6 is a diagram schematically showing a cross-sectional structure of still another embodiment of the nonwoven fabric of the present invention. FIG. 7 is a schematic view showing an apparatus suitably used for producing the nonwoven fabric of the present invention. FIG. 8 is a graph showing the evaluation results of the size of the hydrophilic gradient generated by heat treatment. FIG. 9 is a schematic view showing a cross-sectional structure of a nonwoven fabric produced in a comparative example.

Detailed Description of the Invention

An object of the present invention relates to providing a nonwoven fabric that can eliminate the disadvantages of the above-described conventional technology, an efficient or simple manufacturing method of the nonwoven fabric, and the like.

Hereinafter, the present invention will be described based on preferred embodiments thereof.
The nonwoven fabric of the present invention is preferably an air-through nonwoven fabric.
The “air-through nonwoven fabric” referred to in the present invention refers to a nonwoven fabric manufactured through a process of spraying a fluid of 50 ° C. or higher, for example, gas or water vapor, onto a web or a nonwoven fabric, and not only a nonwoven fabric manufactured only in this step, It also includes a nonwoven fabric produced by adding this step to a nonwoven fabric produced by another method, or a nonwoven fabric produced by performing some step after this step.

The nonwoven fabric of the present invention includes not only an air-through nonwoven fabric but also a composite of an air-through nonwoven fabric and a fiber sheet or film material such as another nonwoven fabric.
The non-woven fabric of the present invention is a non-woven fabric using heat-sealing fibers to which a fiber treatment agent containing a specific compound is attached, and is preferably an air-through non-woven fabric.

The fiber treatment agent used in the present invention adheres to the surface of the heat-fusible fiber, and increases the hydrophilicity of the fiber surface as compared with that before attaching the fiber treatment agent.

The non-woven fabric of the present invention uses a heat-sealing fiber to which a fiber treatment agent containing the above-described components (A), (B) and (C) is attached as one type of constituent fibers. This fiber treatment agent is used for the purpose of controlling the hydrophilicity of the nonwoven fabric of the present invention.

It is sufficient that the heat-sealing fiber to which the fiber treatment agent is attached is present in any part of the nonwoven fabric. Moreover, the nonwoven fabric of this invention may be comprised only from the heat sealing | fusion fiber to which this fiber processing agent adhered, or may contain the other 1 type, or 2 or more types of fiber additionally.

The nonwoven fabric of the present invention may have a single layer structure or a multilayer structure. The air-through nonwoven fabric NW1 and the air-through nonwoven fabric NW2 which are preferred embodiments of the nonwoven fabric of the present invention have a multilayer structure including a first layer and a second layer. The first layer and the second layer are adjacent and in direct contact with each other, and no other layer is interposed between the two layers. The above-described heat-fusible fiber to which the fiber treating agent is attached is included in at least one of the first layer and the second layer. For example, the first layer includes the heat-sealing fiber, the second layer includes the heat-sealing fiber, or both the first layer and the second layer include the heat-sealing fiber. It is out.

The first layer and the second layer are distinguished from each other by factors such as the type of material of the fibers constituting the layers, the thickness of the fibers, the presence / absence of hydrophilic treatment, and the layer formation method. When the cross section in the thickness direction of the air-through nonwoven fabric of the present invention is enlarged with an electron microscope, the boundary portion between both layers can be observed due to these factors.

The air-through nonwoven fabric NW1 and the air-through nonwoven fabric NW2 may each have the first layer side as a use surface or the second layer side as a use surface. Which side is used is determined according to the specific application of the air-through nonwoven fabric. For example, when the air-through nonwoven fabric NW1 or the air-through nonwoven fabric NW2 is used as the top sheet of the absorbent article, the use of the first layer side can maximize the various characteristics of the air-through nonwoven fabric. preferable.

The fiber treatment agent used for the nonwoven fabric of the present invention and the fiber treatment agent for nonwoven fabric treatment of the present invention are the above-mentioned (A) component, (B) component and (C) component, that is, polyorganosiloxane, alkyl phosphate ester, and An anionic surfactant represented by the general formula (1) described later is contained. The fiber to which the fiber treatment agent containing these three components is attached is subjected to a heat treatment, so that the polyorganosiloxane promotes the penetration of the anionic surfactant having an alkyl chain into the fiber. Changes to a lower value by heat treatment. This is because the polysiloxane chain of the polyorganosiloxane and the alkyl chain of the anionic surfactant are incompatible with each other, so the anionic surfactant penetrates into the more familiar fiber when the fiber is heated and melted. It is thought to happen because of this. Among them, the anionic surfactant represented by the general formula (1) has a bulky alkyl group and can penetrate into the fiber so as to wrap around the hydrophilic group. Penetration into the fiber is easy to promote. Thereby, for example, in the step of blowing hot air onto the web, which is one step of the manufacturing process described later, 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). Therefore, the amount of heat received differs between the fiber on the hot air blowing surface and the fiber on the opposite side, and the contact angle value of the fiber also changes between the fiber on the hot air blowing surface and the fiber on the opposite side. It will be. Using this, a nonwoven fabric having a gradient in hydrophilicity is produced from one surface side, which is the first surface when viewed in plan, to the other surface side, which is the second surface opposite to the first surface. can do. Hereinafter, each component will be described.

[Component (A)]
As the polyorganosiloxane, any of linear ones and those having a crosslinked two-dimensional or three-dimensional network structure can be used. Preferably it is substantially linear.

Specific examples of suitable polyorganosiloxanes are alkylalkoxysilanes, arylalkoxysilanes, alkylhalosiloxane polymers or cyclic siloxanes, and the alkoxy groups are typically methoxy groups. 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 is a polyorganosiloxane modified with a highly hydrophilic POE chain from the viewpoint of further promoting the penetration of the surfactant and increasing the contact angle of the fiber surface by heating. It is a concept that does not include.

The most typical polyorganosiloxane preferred in the present invention includes polydimethylsiloxane, polydiethylsiloxane, polydipropylsiloxane and the like, and 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, still more preferably 200,000 or more, preferably 1,000,000. Hereinafter, more preferably 800,000 or less, 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 weight average molecular weight of preferably 100,000 or more, more preferably 150,000 or more, further preferably 200,000 or more, and preferably Is not more than 1 million, more preferably not more than 800,000, still more preferably not more than 600,000. The other one has a weight average molecular weight of preferably less than 100,000, more preferably not more than 50,000, more preferably 30,000. It is 5,000 or less, more preferably 20,000 or less, preferably 2000 or more, more preferably 3000 or more, and still more preferably 5000 or more. A preferable blending ratio (the former: latter) 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, it is 1: 5 to 2: 1.

The weight average molecular weight of the polyorganosiloxane is measured using GPC. 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

The content of the polyorganosiloxane in the fiber treatment agent is preferably 1% by mass or more, and more preferably 5% by mass or more from the viewpoint of increasing the change in hydrophilicity due to heat treatment. Moreover, 30 mass% or less is preferable from a viewpoint which is easy to absorb a liquid on the nonwoven fabric surface, and 20 mass% or less is still more preferable. For example, the content of the polyorganosiloxane in the fiber treatment agent is preferably 1% by mass or more and 30% by mass or less, and more preferably 5% by mass or more and 20% by mass or less.

Furthermore, when the nonwoven fabric according to the present invention is applied to the absorbent article as a top sheet, the viewpoint of preventing the hydrophilicity on the top side from being excessively lowered, that is, the liquid flow distance described later becomes long, and the excretory liquid is applied to the skin. Also from the viewpoint of preventing the amount of adhesion from increasing, the content of the polyorganosiloxane in the fiber treatment agent is preferably within the above range.

Commercially available products can also be used as the polyorganosiloxane as the 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 can be used.

[(B) component]
The component (B), an alkyl phosphate ester, is intended to improve the properties of raw cotton through the card machine and the uniformity of the web, thereby improving the productivity of the nonwoven fabric and preventing the quality from deteriorating. It is blended in the treatment agent.
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 16 to 18 carbon chains. 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 blending ratio of the component (B) in the fiber treatment agent is preferably 5% by mass or more, more preferably 10% by mass or more, from the viewpoints of card machine passability and web uniformity, and heat treatment. From the viewpoint of preventing the fiber from being hydrophobized by the polyorganosiloxane resulting from the above, it is preferably 30% by mass or less, more preferably 25% by mass or less.

[Component (C)]
The component (C) is an anionic surfactant represented by the general formula (1) shown above. (C) component points out the component which does not contain the alkyl phosphate ester which is (B) component. Moreover, (C) component 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 (1) is —SO ₃ M, that is, the hydrophilic group is a sulfonic acid or a salt thereof, include, for example, 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 compounds sulfonated at the alpha position, 2-sulfotetradecanoic acid 1-ethyl ester (or amide) sodium salt, 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 dialkyl sulfonic 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 sulfonic acid or a salt thereof include the following anionic surfactants.

Examples of the anionic surfactant in which X in the general formula (1) is —OSO ₃ M, that is, the hydrophilic group is sulfuric acid or a salt thereof, include dialkyl sulfates, and specific examples thereof include 2-ethylhexyl. Compounds with sulfated alcohols such as sodium sulfate and sodium 2-hexyldecyl sulfate, and alcohols with branched chains such as polyoxyethylene 2-hexyldecyl sulfate and polyoxyethylene 2-hexyldecyl sulfate And hydroxy fatty acid esters (or 12-sulfate stearic acid 1-methyl ester (or amide) 3-sulfate hexanoic acid 1-methyl ester (or amide) And compounds obtained by sulfating amides).

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

As the anionic surfactant in which X in the general formula (1) is —COOM, that is, the hydrophilic group is a carboxylic acid or a salt thereof, a dialkylcarboxylic acid can be mentioned, and specific examples thereof include 11-ethoxyhepta. Hydroxy fatty acid chlorides, such as compounds in which the hydroxy moiety of hydroxy fatty acids such as sodium decanecarboxylate and sodium 2-ethoxypentacarboxylate is alkoxylated and the fatty acid moiety is sodiumated, and the amino group of amino acids such as sarcosine and glycine are alkoxylated And compounds obtained by reacting carboxylic acid in the amino acid part with sodium, and compounds obtained by reacting fatty acid chloride with the amino group of arginic acid.

In the present invention, as a fiber treating agent, a heat treating property treated with a fiber treating agent is obtained by using a fiber treating agent in which an anionic surfactant represented by the general formula (1) and polyorganosiloxane are blended. The fiber becomes a fiber whose hydrophilicity tends to be lowered by heat treatment. The reason for this is that polyorganosiloxane promotes the penetration of an anionic surfactant having two or more alkyl chains into the fiber, so that the hydrophilicity of the fiber surface tends to be lowered by heat treatment. This is because the polysiloxane chain of the polyorganosiloxane and the alkyl chain of the anionic surfactant are incompatible with each other, so that the anionic surfactant penetrates when the fiber is heated and melted into the more familiar fiber. Presumed to happen.

The blending ratio of the component (C) in the fiber treatment agent 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. When it becomes too high, it is preferably 20% by mass or less, more preferably 13% by mass or less, from the viewpoint of easily holding the liquid and impairing dryness. The blending ratio of the component (C) 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.

The content ratio (the former: latter) of the polyorganosiloxane of component (A) and the anionic surfactant of component (C) in the fiber treatment agent is preferably 1: 3 to 4: 1 by mass ratio. The ratio is preferably 1: 2 to 3: 1. In addition, the content ratio (the former: latter) of the polyorganosiloxane of component (A) and the alkyl phosphate ester of component (B) in the fiber treatment agent is preferably a mass ratio of 1: 5 to 10: 1. More preferably, it is 1: 2 to 3: 1.

The fiber treatment agent used in the present invention may contain other components in addition to the components (A) to (C) described above. As other components to be blended in addition to the components (A) to (C), 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 alkyl betaines. Among alkylbetaines, alkyl (C1-30) dimethylbetaine, alkyl (C1-30) amidoalkyl (C1-4) dimethylbetaine, alkyl (C1-30) dihydroxyalkyl (C1 ~ 30) Betaine-type amphoteric surfactants such as betaine and sulfobetaine-type amphoteric surfactants, alanine type [alkyl (carbon number 1-30) aminopropionic acid type, alkyl (carbon number 1-30) imino Dipropionic acid type, etc.] Amphoteric surfactants, Glycine types such as alkylbetaines [Alkyl (carbon number 1-30) aminoacetic acid type, etc.] Amino acid type amphoteric surfactants, such as amphoteric surfactants, alkyls (carbon number 1 ~ 30) Aminosulfonic acid type amphoteric surfactants such as taurine type. 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 polyhydric alcohol fatty acid esters such as glycerin fatty acid esters, poly (preferably n = 2 to 10) glycerin fatty acid esters, sorbitan fatty acid esters (preferably those having 8 to 8 carbon atoms of fatty acids). 60), polyoxyalkylene (added mole number 2-20) alkyl (carbon number 8-22) amide, polyoxyalkylene (added mole number 2-20) alkyl (carbon number 8-22) ether, polyoxyalkylene-modified silicone And amino-modified silicone. Of these, glycerin fatty acid ester is preferable, and glycerin monocaprylate is more preferable.

The fiber treatment agent used in the nonwoven fabric of the present invention and the fiber treatment agent for nonwoven fabrics of the present invention may contain a treatment agent such as an anti-sticking agent such as modified silicone.

[Fiber treated with fiber treatment agent]
The heat-fusible fiber of the present invention is treated with a fiber treatment agent, and the above-described fiber treatment agent is attached to at least the surface.
The heat-fusible fiber used in the present invention is a fiber constituting the heat-fusible nonwoven fabric. Examples of the heat-fusible fiber include a heat-fusible core-sheath type composite fiber and a non-heat-extensible fiber. Examples thereof include fibers, heat shrink fibers, three-dimensional crimp fibers, latent crimp fibers, and hollow fibers. In the present invention, it is preferable to use a heat-fusible core-sheath composite fiber.
The heat-fusible core-sheath type conjugate fiber of the present invention is a heat-fusible core-sheath type conjugate fiber similar to the heat-fusible core-sheath type conjugate fiber before the fiber treatment agent is attached. . 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.

Examples of the heat-fusible core-sheath composite fiber to which the fiber treatment agent is attached include, for example, “a sheath portion containing a polyethylene resin and a core made of a resin component having a higher melting point than the polyethylene resin” described in JP 2010-168715 A A core-sheath type composite fiber having a part (hereinafter, this fiber is referred to as a core-sheath type composite 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 like. A high density polyethylene of ~ 0.965 g / cm ³ is preferred. The resin component constituting the sheath portion of the core-sheath type composite fiber P is preferably a polyethylene resin alone, but other resins can also be blended. 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 70 mass% or more and 100 mass% or less especially polyethylene resin. Further, the polyethylene resin constituting the sheath portion 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 described above during heat treatment. 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 can be easily manufactured, 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 core-sheath composite fiber to which the fiber treatment agent is attached is preferably a fiber whose length is extended by heating (hereinafter also referred to as a heat-extensible composite 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 and / or in a state where it can be extended by heating. 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 conjugate fiber has a first resin component that constitutes a core portion and a second resin component that comprises a polyethylene resin and constitutes a sheath portion, and the first resin component is a second resin component. Has a higher melting point. 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 were determined by using a differential scanning calorimeter (DSC6200, manufactured by Seiko Instruments Inc.), and performing thermal analysis of a finely cut fiber sample (sample weight 2 mg) at a heating rate of 10 ° C./min. 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 fusion point strength of the fiber can be measured is used as the softening point as the temperature at which the molecules of the second resin component begin to flow, and this is used instead of the melting point.

The preferred orientation index of the first resin component in the heat-stretchable 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. More preferably, it is 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 JP 2010-168715 A. A method for achieving the orientation index as described above for each resin component in the thermally extensible composite fiber 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 composite fiber preferably has a thermal elongation rate of 0.5 to 20% 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), Preferably it is 3 to 20%, more preferably 5.0 to 20%. 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 ratio (mass ratio, the former: latter) of 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. : 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 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 thickness of 10 to 35 μm, particularly 15 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 Laid-Open No. 2005-350836, Japanese Patent Laid-Open No. 2007-303035, Japanese Patent 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 0.1 μm to 2 μm, for example, 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 or the like has high concealment 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 at any content, but from the viewpoint of enhancing concealability, the amount of titanium oxide to be contained in the heat-fusible fiber is preferably 0.5% by mass with respect to the total mass of the fiber. Above, more preferably 1 mass% or more, from the viewpoint of productivity, fiber strength properties, card process properties in the nonwoven fabric manufacturing process, cut property in the post-processing step, preferably 5 mass% or less, More preferably, it is 4.5 mass% or less.

[Treatment of fiber with fiber treatment agent]
In the heat-fusible core-sheath type composite fiber of the present invention, the hydrophilicity of the surface of the fiber is increased as compared with the case where the fiber treating agent is adhered, as compared with before the adhesion.
The adhesion amount of the fiber treatment agent is preferably 0.1% by mass or more, more preferably, from the viewpoint of increasing the hydrophilicity of the fiber as a proportion of the total mass of the heat-sealable core-sheath composite fiber excluding the fiber treatment agent. It is 0.1 to 1.5% by mass, and more preferably 0.2 to 1.0% by mass.

As the method for attaching the fiber treatment agent to the fiber surface, various known methods can be employed without any particular limitation. 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.

The heat-fusible fiber of the present invention is preferably used for the production of sheet materials such as webs and nonwoven fabrics. In addition, a part of the layered body can be formed on the manufactured sheet material. And the hydrophilic property of a desired part can be reduced by heat-processing after the manufacturing process of the sheet material, and manufacture of a sheet material and a laminated body. The decrease in hydrophilicity may decrease the entire hydrophilicity of the sheet material, or may decrease a part of the sheet material. The thickness (fineness) of the fiber is selected in an appropriate range according to the specific application such as a non-woven fabric produced by using the fiber, but from the viewpoint of producing a non-woven fabric that is soft and has a good touch. Is preferably 1.0 to 10.0 dtex, and more preferably 2.0 to 8.0 dtex.

The non-woven fabric of the present invention may be a mixture of heat-extensible fibers and non-heat-extensible fibers as heat-fusible fibers. The non-heat-extensible fiber is a bicomponent composite fiber that includes a high-melting component and a low-melting component, and the low-melting component is continuously present in the length direction on at least a part of the fiber surface. The form of the composite fiber (non-heat-extensible fiber) includes various forms such as a core-sheath type and a side-by-side type, and any form can be used. The heat-fusible composite fiber is drawn at the raw material stage. The term “stretching treatment” as used herein refers to a stretching operation with a stretching ratio of about 2 to 6 times. The mixing ratio of the heat-extensible fiber and the non-heat-extensible fiber is preferably 1: 9 to 9: 1 for the former: the latter and more preferably 4: 6 to 6: 4 in terms of mass ratio. 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.

Thus, a nonwoven fabric having a plurality of portions having different hydrophilicities can be obtained by heat-treating a web or nonwoven fabric produced using heat-fusible fibers.

In the heat-fusible fiber of the present invention, the contact angle of water with respect to the fiber taken out from the nonwoven fabric is preferably 90 degrees or less. When the hydrophilicity of the surface is further increased by the fiber treatment agent, it becomes possible to form a plurality of regions having greatly different hydrophilicities on the fiber itself or a nonwoven fabric produced using the fiber. From the same viewpoint, the heat-fusible core-sheath composite fiber taken out from the nonwoven fabric of the present invention has a contact angle with water of preferably 90 degrees or less, more preferably 85 degrees or less, and hydrophilicity. If it is too high, the liquid tends to be held, and therefore it is preferably at least 60 °, more preferably at least 65 °. Further, it is preferably 65 to 85 degrees, and more preferably 70 to 80 degrees. A decrease in hydrophilicity is synonymous with an increase in contact angle.

The contact angle of water with the fiber taken out from the nonwoven fabric is measured by the following method. As a measuring device, an automatic contact angle meter MCA-J manufactured by Kyowa Interface Science Co., Ltd. is used. Distilled water is used for contact angle measurement. The amount of liquid discharged from an ink jet type water droplet discharge part (manufactured by Cluster Technology Co., Ltd., pulse injector CTC-25 having a discharge part pore diameter of 25 μm) is set to 20 picoliters, and a water drop is dropped just 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 msec. In the recorded video, the first image of water droplets on the fiber taken out from the nonwoven 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, image processing algorithm is non-reflective, image processing image mode is frame, threshold level is 200, and curvature correction is not performed). Calculate the contact angle.
In addition, the sample for measurement (fiber obtained by taking out from a nonwoven fabric) is the fiber located in the corresponding part in the top part P1 of a convex part, the recessed part vicinity part, and back surface (flat surface) P2 shown in FIG.1 (b) from an outermost layer. Cut with a fiber length of 1 mm, place the fiber on a sample table of a contact angle meter, keep it horizontal, and measure two different contact angles for each fiber. In each of the aforementioned parts, 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 each contact angle.

FIG. 1 (a) and FIG. 1 (b) are views showing a nonwoven fabric 1 which is an embodiment of the nonwoven fabric of the present invention. After forming a web from the heat-fusible fiber of the present invention, one of the webs is shown. It was obtained by reducing the hydrophilicity of the part. As a method for obtaining a web from the heat-fusible fiber of the present invention, various known methods such as a card method, an airlaid method, and a spunbond method can be used. As shown in FIG. The method used (card method) is preferred.
As shown in FIG. 2, the nonwoven fabric shown in FIG. 1 (a) and FIG. 1 (b) forms a web 12 using a card machine 11 with a short fiber aggregate of fibers whose hydrophilicity is lowered by heat as a raw material. Then, the web 12 was introduced into an embossing device 13 having a pair of

rolls

14 and 15 for embossing, and the web 16 after embossing was heat treated by a hot-air treatment device 17 using an air-through method. Is.
One of the pair of rolls used for embossing is an embossing roll 14 in which convex portions for embossing in a lattice pattern are formed on the peripheral surface, and the other has a smooth peripheral surface and faces the embossing roll. The flat roll 15 is arranged. Embossing is performed by pressing and compressing the web between the convex portion of the embossing roll 14 and the smooth peripheral surface of the flat roll 15. Thereby, the nonwoven fabric which has the thin part (embossing part) 18 formed by the embossing, and the thick part 19 other than that is obtained.

In one embodiment of producing the nonwoven fabric of the present invention, the temperature applied to the web 12 during embossing when producing the nonwoven fabric 1 in this way is set to the sheath portion of the heat-fusible core-sheath conjugate fiber. In the subsequent hot air treatment, a temperature not lower than the melting point of the polyethylene resin and not higher than the melting point of the resin component of 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 portion (embossed portion) that has been consolidated by embossing has little or no amount of hot air to pass, and hot air passes through thicker portions other than the embossed portion. , Hydrophilicity decreases.
As a result, the thin portion 18 and / or its peripheral portion formed by embossing becomes a hydrophilic portion, and becomes relatively hydrophobic as it becomes closer to the other thick portion 19, and the thickest portion becomes thicker. A nonwoven fabric in which the vicinity of the portion is a portion exhibiting the maximum hydrophobicity is obtained. 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.

The nonwoven fabric 1 shown in FIGS. 1 (a) and 1 (b) has a single layer structure. The nonwoven fabric 1 has a concavo-convex surface 10b having one concavo-convex shape, and the other surface is flat or a flat surface 10a having a smaller degree of concavo-convexity than the concavo-convex surface.
The thick portion 19 and the thin portion 18 in the nonwoven fabric 1 form a convex portion 119 and a concave portion 118 on the concave-convex surface 10 b of the nonwoven fabric 1. The recess 118 includes a first linear recess 118a extending in parallel with each other and a second linear recess 118b extending in parallel with each other, and the first linear recess 118a and the second linear recess 118b. And intersect at a predetermined angle. The convex portion 119 is formed in a rhombus-shaped closed region surrounded by the concave portion 118.

The top part P1 of the thick part is the top part P1 of the convex part 119 formed on the uneven surface 10b of the nonwoven fabric by the thick part 19. Compared with the top portion P1 of the thick portion 19, the thin portion 18 or its neighboring portion P3 has high hydrophilicity. When liquid enters from the uneven surface 10b side, the liquid is introduced to the flat surface 10a side. It is preferable in terms of easy removal and less liquid residue in the nonwoven fabric 1. Further, it is preferable that the hydrophilicity gradually increases from the top portion P1 of the thick portion 19 toward the thin portion (embossed portion) 18 or its vicinity P3.

The uneven surface 10b of the nonwoven fabric 1 is directed to the embossing roll 14 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 of the side which sprays directly. Therefore, when a heat-extensible conjugate fiber is used as a constituent fiber of the nonwoven fabric, the heat-extensible conjugate fiber extends more greatly on the uneven surface 10b than on the flat surface 10a. Therefore, the fiber diameter in the surface of the flat surface 10a becomes larger than the fiber diameter in the surface of the uneven surface 10b. Further, the hydrophilicity of the thick portion 19 is lower on the uneven surface 10b side than on the flat surface 10a side.

In the manufacturing method of the nonwoven fabric 1, the temperature applied to the web at the time of embossing is from the melting point of the polyethylene resin constituting the sheath portion from the viewpoint of suppressing changes in the hydrophilicity at the embossed portion and / or its vicinity (peripheral portion). It is preferably 20 ° C. or lower and lower than the melting point of the resin component constituting the core. 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.
According to the heat-fusible core-sheath-type conjugate fiber of the present invention or a nonwoven fabric produced using the same, a nonwoven fabric having a plurality of portions with greatly different hydrophilicity is produced without requiring a complicated device or a special device. When used as a surface sheet of absorbent articles such as sanitary napkins, panty liners, disposable diapers, etc., the obtained nonwoven fabric has a good touch and is unlikely to cause liquid residue on the surface. Liquid flow hardly occurs and shows good absorption performance.
In addition, in this specification, a surface material and a surface sheet are synonymous.

The hydrophilicity of the heat-fusible core-sheath composite fiber of the present invention or the web containing the same is lowered by heat treatment. The hydrophilic part and the hydrophilic part in the nonwoven fabric of the present invention need only have a high degree of hydrophilicity in comparison with the part whose hydrophilicity has been lowered by heat treatment. In addition, the hydrophobic part or the hydrophobic part may be a part where the hydrophilicity is lowered before the hydrophilicity is lowered by heat treatment or compared with a part where the hydrophilicity is not lowered. The lowering of the hydrophilicity may be any treatment that lowers the hydrophilicity in comparison with that before the heat treatment. A decrease in hydrophilicity is synonymous with an increase in contact angle. Here, the decrease in hydrophilicity means that the difference in contact angle is 2 degrees or more, preferably 2.5 degrees or more, more preferably 3 degrees or more, and 5 degrees or more. More preferably, it is. Further, it is preferably 10 degrees or less, more preferably 8 degrees or less, and even more preferably 7 degrees or less.

The nonwoven fabric of the present invention may be made three-dimensional by secondary processing after partially lowering the hydrophilicity, and may be appropriately subjected to additional processes such as performing a hydrophilization treatment only for a part. Moreover, the nonwoven fabric of this invention may have a hydrophilicity gradient in one of the thickness direction or the plane direction, and may have a hydrophilicity gradient in the thickness direction and a plane direction.

The non-woven fabric according to the present invention can be applied to various fields by taking advantage of a hydrophilicity gradient, such as partly hydrophilic and partly hydrophobic or hydrophilicity-reduced part. 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, or an objective wiper.

The basis weight of the web or nonwoven fabric used for the production of the nonwoven fabric is selected within a suitable range depending on the specific use of the intended nonwoven fabric. The basis weight of the finally obtained nonwoven fabric 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 the nonwoven fabric 1 is used as, for example, a surface sheet of an absorbent article, the basis weight is preferably 10 to 80 g / m ² , particularly preferably 15 to 60 g / m ² . When used for the same purpose, the thickness of the convex portion 119 (thick portion 19) in the nonwoven fabric 1 is preferably 0.5 to 3 mm, particularly 0.7 to 3 mm in the state after bulk recovery by hot air. On the other hand, the thickness of the recess 118 (thin portion 18) is preferably 0.01 to 0.4, particularly 0.02 to 0.2 mm. The thickness of the recess 118 is not substantially changed before and after the hot air is blown. The thickness of the convex part 119 and the concave part 118 is measured by observing the longitudinal section of the nonwoven fabric 1. 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 (manufactured by Keyence Corporation, VHX-900), and the thicknesses of the convex portions 119 and the concave portions 118 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 concave portion 118 and the convex portion 119 in the nonwoven fabric 1 is represented by an embossing rate (an embossed area ratio, that is, a ratio of the total area of the concave portion 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%, more preferably 10 to 25%. The embossing rate is measured by the following method. First, using a microscope (manufactured by Keyence Co., Ltd., VHX-900), an enlarged surface photograph of the nonwoven fabric 1 is obtained. An embossed area U is calculated.
The embossing rate can be calculated by the formula (U / T) × 100.

The air-through nonwoven fabric NW1, which is a preferred embodiment of the nonwoven fabric of the present invention, includes the thermoplastic fiber to which the fiber treatment agent is adhered, and thus has hydrophilicity along the thickness direction when viewed as a whole of the air-through nonwoven fabric. Has a slope. Specifically, the first layer is virtually divided into two in the thickness direction, and a portion farther from the second layer among the two divided portions is defined as a first layer first portion, When the portion closer to the layer is the first layer second portion, when the hydrophilicity of the first layer first portion, the first layer second portion, and the second layer is compared, the following (11) and The relationship of (12) is satisfied.
(11) The first layer second portion has higher hydrophilicity than the first layer first portion.
(12) The hydrophilicity of any part of the second layer is higher than that of the second part of the first layer.

In the air-through nonwoven fabric NW1, the first layer first portion, the first layer second portion, and the second layer have a hydrophilicity relationship between the first layer, the first portion, the first layer, the second portion, and the second layer. Any site in “Any part in the second layer” refers to a part having the highest hydrophilicity among the hydrophilicities measured along the thickness direction of the second layer. The same applies to the first layer first part and the first layer second part, and the hydrophilicity of the first layer first part and the first layer second part refers to the hydrophilicity of these parts along the thickness direction. It is the said hydrophilicity in the site | part which shows the highest hydrophilicity when measured. The “hydrophilicity” referred to in the present invention is determined based on the contact angle of the fiber measured by the method described below. Specifically, a low hydrophilicity is synonymous with a large contact angle, and a high hydrophilicity is synonymous with a small contact angle.

[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 Co., Ltd., pulse injector CTC-25 having a discharge part pore diameter of 25 μm) is set to 20 picoliters, and a water drop is dropped just 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 msec. In the recorded video, the first image of water droplets on the fiber taken out from the nonwoven 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 the curvature is not corrected). And 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.

As described above, the air-through nonwoven fabric NW1 has higher hydrophilicity from the first part toward the second part in the first layer. In addition, the air-through nonwoven fabric NW1 has a higher hydrophilicity from the first layer second portion toward the second layer. Due to the fact that such a gradient is provided in the hydrophilicity in the thickness direction, when the liquid is supplied to the first surface side of the air-through nonwoven fabric NW1, the liquid quickly permeates through the nonwoven fabric. . Therefore, it is difficult for the liquid to flow along the surface on the first surface side. As a result, it is difficult for the liquid to remain on the surface on the first surface side, which is the surface supplied with the liquid. These remarkable effects become particularly remarkable when the air-through nonwoven fabric NW1 is used as a surface sheet of an absorbent article with the surface on the first layer side facing the skin.

FIGS. 3 to 5 show various specific examples of the air-through nonwoven fabric NW1 having the above-described hydrophilicity gradient. Hereinafter, the air-through nonwoven fabric of the form shown in these drawings will be described.

3 has a first layer 10 and a second layer 20. The first layer 10 and the second layer 20 are in direct contact with each other, and there are no other layers interposed between the two layers. The first layer 10 and the second layer 20 are each a single fiber layer, and are not composed of a multi-layer laminate that is further subdivided. The first layer 10 and the second layer 20 are bonded to each other on the entire area of the opposing surfaces, and no gap is generated between the both

layers

10 and 20. In addition, in FIG. 3, although the 1st layer 10 and the 2nd layer 20 are represented by the same thickness, this is because each

layer

10 and 20 was shown typically, In actual air through nonwoven fabric 1A, The thickness of the first layer 10 and the second layer 20 may be different.

The first layer 10 and the second layer 20 are both composed of randomly deposited fibers. The fibers constituting the first layer 10 are fused by an air-through method at the intersections of the fibers. The same applies to the second layer 20. In addition, at the boundary between the first layer 10 and the second layer 20, the intersection of the fibers constituting the first layer 10 and the fibers constituting the second layer 20 is fused by an air-through method. In addition, the fibers constituting the first layer 10 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 20 and also at the boundary between the first layer 10 and the second layer 20.

In the nonwoven fabric of this invention, when the 1st layer 10 which consists of a single layer is virtually divided into two in the thickness direction, it is a site | part on the side far from the 2nd layer 20 among the two parts divided into two. Is called the first layer first portion 11, and the portion closer to the second layer 20 is called the first layer second portion 12. Since the first layer 10 is composed of a single layer, there is no boundary between the first portion 11 and the second portion 12. Further, the fibers constituting the first part 11 and the fibers constituting the second part 12 are the same.

In the first layer 10 of the nonwoven fabric 1 </ b> A of the embodiment shown in FIG. 3, the second portion 12 is more hydrophilic than the first portion 11. In order to provide such a gradient of hydrophilicity in the first layer 10, it is preferable that the first layer 10 includes the heat-fusible fiber to which the fiber treatment agent described above is attached. In this case, the hydrophilicity of the first layer 10 may be gradually increased from the first part 11 toward the second part 12, or the hydrophilicity is stepped from the first part 11 toward the second part 12. The shape may be higher. From the viewpoint of improving the permeation of the liquid along the thickness direction, the hydrophilicity is preferably gradually increased from the first portion 11 toward the second portion 12. From the viewpoint of providing a gradient of hydrophilicity in which the hydrophilicity gradually increases, it is preferable that the first layer 10 includes the heat-fusible fiber to which the fiber treatment agent described above is attached.

Regardless of whether the hydrophilicity is gradually increased or stepwise, in the first layer 10, the contact angle of water with respect to the fibers contained in the first layer first portion 11 is 70 degrees or more, particularly It is preferable that it is 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 contrast to the first layer 10 having a gradient in hydrophilicity, in the present embodiment, the second layer 20 has the same hydrophilicity in any part of the second layer 20. The hydrophilicity of the second layer 20 is higher than the hydrophilicity of the first layer second portion 12. Thus, the nonwoven fabric 1A of the present embodiment has higher hydrophilicity in the order of the first layer first portion 11, the first layer second portion 12, and the second layer 20. The contact angle of water with respect to the fibers contained in the second layer 20 is 20 degrees or more, particularly 30 degrees or more, provided that the contact angle of water with respect to the fibers contained in the first layer first portion 12 is smaller. Is preferably 75 degrees or less, and particularly preferably 65 degrees or less. For example, the contact angle of water with respect to the fibers contained in the second layer 20 is preferably 20 degrees or more and 75 degrees or less, and more preferably 30 degrees or more and 65 degrees or less.

In the present embodiment, as described above, the hydrophilicity of the second layer 20 is the same in any part. In order to form such a second layer 20, for example, the fibers are hydrophilic. What is necessary is just to use the fiber processing agent called the oil agent conventionally used in order to provide. Typical examples of such fiber treatment agents include various surfactants. As the surfactant, anionic, cationic, zwitterionic and nonionic surfactants can be used.

Examples of anionic surfactants include alkyl phosphate salts, alkyl ether phosphate salts, dialkyl phosphate salts, dialkyl sulfosuccinate salts, alkyl benzene sulfonate salts, alkyl sulfonate salts, alkyl sulfate salts, secondary alkyl sulfate salts and the like ( Any of the above alkyl preferably has 6 to 22 carbon atoms.) Examples of the alkali metal salt include sodium salt and potassium salt.

Examples of the cationic surfactant include alkyl (or alkenyl) trimethylammonium halide, dialkyl (or alkenyl) dimethylammonium halide, alkyl (or alkenyl) pyridinium halide and the like. These compounds have 6 to 18 carbon atoms. Those having an alkyl group or an alkenyl group are preferred. Examples of the halogen in the halide compound include chlorine and bromine.

Examples of zwitterionic surfactants include alkyl (C1-30) dimethylbetaine, alkyl (C1-30) amidoalkyl (C1-4) dimethylbetaine, alkyl (C1-30) dihydroxy. Betaine-type zwitterionic surfactants such as alkyl (carbon number 1-30) betaines and sulfobetaine-type amphoteric surfactants, alanine type [alkyl (carbon numbers 1-30) aminopropionic acid type, alkyl (carbon number 1) To 30) iminodipropionic acid type, etc.] zwitterionic surfactant, glycine type [alkyl (carbon number 1-30) aminoacetic acid type, etc.] amino acid type zwitterionic surfactant such as zwitterionic surfactant, alkyl (carbon (Formula 1-30) Aminosulfonic acid type zwitterionic surfactants such as taurine type.

Examples of nonionic surfactants include polyhydric alcohol 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 to 22 carbon atoms of fatty acid). ), Polyoxyethylene alkyl (carbon number 8 to 22) amide, polyoxyethylene alkyl (carbon number 8 to 22) ether, amino-modified silicone, and the like.

In addition, it is preferable that the constituent fiber of the second layer 20 is not treated with the above-described fiber treatment agent containing the components (A) to (C).

From the viewpoint of smoother liquid permeation from the first layer 10 to the second layer 20, the contact angle of water with respect to the fibers contained in the first layer second portion 12 and the water with respect to the fibers contained in the second layer 20. The difference from the contact angle (first layer second portion 12−second layer 20) is preferably 1 degree or more, particularly 10 degrees or more, more preferably 20 degrees or more, and 50 degrees or less, particularly 40 degrees or less. Preferably there is. For example, the difference is preferably 1 ° to 50 °, more preferably 10 ° to 40 °.

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 20 (first layer first portion 11− The second layer 20) is 2 degrees or more, particularly 10 degrees or more, and more preferably 20 degrees or more, provided that the contact angle difference between the first layer second portion 12 and the second layer 20 is larger than that described above. Is preferably 65 ° or less, and particularly preferably 50 ° or less. For example, the difference is preferably 2 ° to 65 °, more preferably 10 ° to 50 °.

In order to produce an air-through nonwoven fabric composed of each layer and each part having the contact angle as described above, the above-described fiber treatment agent is used, and the hot air blowing conditions in the air-through method described later, that is, the temperature and the air volume of the hot air are appropriately used. It may be controlled to.

Next, the

nonwoven fabrics

1B and 1C of the embodiment shown in FIGS. 4 and 5 will be described. About these

nonwoven fabrics

1B and 1C, although the point which is different from the nonwoven fabric 1A demonstrated previously is demonstrated and the same point is not demonstrated in particular, the description regarding the nonwoven fabric 1A is applied suitably. 4 and 5, the same members as those in FIG. 3 are denoted by the same reference numerals.

In the nonwoven fabric 1B shown in FIG. 4, the first layer 10 has the same configuration as the first layer 10 of the nonwoven fabric 1A shown in FIG. On the other hand, regarding the second layer 20 of the non-woven fabric 1B, when this is virtually bisected in the thickness direction, the portion closer to the first layer 10 out of the two bisected portions is the second. A layer first portion 21 is called, and a portion far from the first layer 10 is called a second layer second portion 22. Since the second layer 20 is composed of a single layer, there is no boundary between the first portion 21 and the second portion 22. Further, the fibers constituting the first part 21 and the fibers constituting the second part 22 are the same.

In the nonwoven fabric 1B according to the present embodiment, when the hydrophilicity of the first layer first portion 11, the first layer second portion 12, the second layer first portion 22, and the second layer second portion 22 is compared. In addition to the relationship (11) described above, that is, the first layer second portion 12 has higher hydrophilicity than the first layer first portion 11, the following (13) and (14) The relationship is also satisfied.
(13) The hydrophilicity of the second layer first portion 21 is higher than that of the first layer second portion 12;
(14) The second layer second portion 22 is more hydrophilic than the second layer first portion 21.

Thus, the nonwoven fabric 1B of this embodiment has a gradient of hydrophilicity with respect to the first layer 10 and also has a gradient of hydrophilicity with respect to the second layer 20. The magnitude relationship of the hydrophilicity is as follows: first layer first part 11 <first layer second part 12 <second layer first part 21 <second layer second part 22. In this case, similarly to the first layer 10 of the nonwoven fabric 1A described above, the second layer 20 may have a gradually increasing hydrophilicity from the second portion 21 toward the second portion 22, or The hydrophilicity may increase stepwise from the two regions 21 toward the second region 22. From the viewpoint of improving the permeation of the liquid along the thickness direction, the hydrophilicity is preferably gradually increased from the second portion 21 toward the second portion 22. From the viewpoint of providing a gradient of hydrophilicity that gradually increases in hydrophilicity, the heat-fusible fiber to which the fiber treatment agent described above is attached is included not only in the first layer 10 but also in the second layer 20. Preferably it is.

In the first layer 10 of the nonwoven fabric 1B, it is preferable that the contact angle of water with respect to the fibers contained in the first layer first portion 11 is 70 degrees or more, particularly 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 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 20 of the nonwoven fabric 1B, the contact angle of water with respect to the fibers contained in the second layer first portion 21 is preferably 50 degrees or more, particularly 55 degrees or more. 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 first portion 21 is preferably 50 degrees or more and 75 degrees or less, and more preferably 55 degrees or more and 70 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 20 degrees or more, particularly 30. 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 20 degrees or more and 70 degrees or less, and preferably 30 degrees or more and 65 degrees or less.

From the viewpoint of smoother liquid permeation from the first layer 10 to the second layer 20, 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, and 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 °.

In order to produce the air-through nonwoven fabric 1B shown in FIG. 4 composed of each layer and each part having the contact angle as described above, the fiber treatment agent described above is used for each layer, and the hot air blowing conditions in the air-through method described later, that is, What is necessary is just to control the temperature and air volume of hot air appropriately. In particular, according to the nonwoven fabric 1B of this embodiment, the same effect as the nonwoven fabric 1A shown in FIG. 3 is exhibited. In particular, since the nonwoven fabric 1B of the present embodiment has a gradient of hydrophilicity with respect to the second layer 20, the effect exhibited by the nonwoven fabric 1A shown in FIG. 3 becomes even more remarkable.

The nonwoven fabric 1C shown in FIG. 5 has a hydrophilicity gradient with respect to the first layer 10 and also has a hydrophilicity gradient with respect to the second layer 20, similarly to the nonwoven fabric 1B shown in FIG. 4 described above. Further, similarly to the nonwoven fabric 1B shown in FIG. 4, the first portion 10 has a higher hydrophilicity in the second portion 12 than the first portion 11, and the second layer 20 also has a higher degree of hydrophilicity than the first portion 21. Also, the second portion 22 has a higher hydrophilicity. The non-woven fabric 1C of the present embodiment is different from the non-woven fabric 1B shown in FIG. 4 in that the degree of hydrophilicity is such that the first layer first part 11 <second layer first part 21 <first layer second part 12 <The second layer is the second portion 22. Except this point, it is the same as the nonwoven fabric 1B shown in FIG.

In short, in the nonwoven fabric 1C of the present embodiment, in addition to the relationship (11) described above, that is, the first layer second portion 12 is more hydrophilic than the first layer first portion 11, An air-through nonwoven fabric that satisfies the following relationships (15), (16), and (17).
(15) The second layer first portion 21 is more hydrophilic than the first layer first portion 11.
(16) The first layer second portion 12 has a higher hydrophilicity than the second layer first portion 21.
(17) The hydrophilicity of the second layer second portion 22 is higher than that of the first layer second portion 12.

Thus, unlike the

nonwoven fabrics

1A and 1B described so far, the nonwoven fabric 1C of the present embodiment has higher hydrophilicity in order from the first layer 10 side toward the second layer 20 side. Instead, the hydrophilicity relationship is reversed between the first layer second portion 12 and the second layer first portion 21. The nonwoven fabric 1C of this embodiment having such a hydrophilicity relationship has the same effects as the

nonwoven fabrics

1A and 1B shown in FIGS. 12 and the second layer first portion 21 are reversed in the relationship of hydrophilicity, the effect that the liquid that has once passed through the nonwoven fabric 1C is difficult to return, and the liquid in the plane direction of the nonwoven fabric 1C. There is also an effect that the liquid permeates through the nonwoven fabric 1C while being diffused. The effect that the liquid is difficult to return is advantageous in that, when the nonwoven fabric 1C is used as the top sheet of the absorbent article, the liquid once absorbed by the absorbent body is difficult to return even when subjected to the wearer's pressure resistance. It is. Moreover, when the nonwoven fabric 1C is used as the surface sheet of the absorbent article, the effect that the liquid is transmitted while diffusing in the plane direction of the nonwoven fabric 1C is that the liquid is absorbed in all the portions in the plane direction of the absorbent body. This is advantageous in that the absorption performance of the absorber can be effectively utilized.

In the first layer 10 of the nonwoven fabric 1C, the contact angle of water with respect to the fibers contained in the first layer first portion 11 is preferably 70 degrees or more, particularly preferably 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 20 of the nonwoven fabric 1C, it is preferable that the contact angle of water with respect to the fibers contained in the second layer first portion 21 is 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 at least. 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 effect that the liquid once transmitted through the nonwoven fabric 1C is difficult to reverse and the effect that the liquid permeates through the nonwoven fabric 1C while the liquid diffuses in the plane direction of the nonwoven fabric 1C, the second layer first The difference between the contact angle of water with respect to the fibers contained in the 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, particularly preferably 2 degrees or more, and 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 10 to the second layer 20, 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 degrees. Or less. For example, the difference is preferably 2 ° to 55 °, more preferably 5 ° to 45 °.

In the first layer 10 of the nonwoven fabric 1C of the present embodiment, the hydrophilicity may gradually increase from the first part 11 toward the second part 12, or, alternatively, from the first part 11 toward the second part 12. The hydrophilicity may be increased stepwise. On the other hand, in the second layer 20, the hydrophilicity may be gradually increased from the second part 22 toward the first part 21, or the hydrophilicity is stepped from the second part 22 toward the first part 21. The shape may be higher.

In order to manufacture the air-through nonwoven fabric 1C shown in FIG. 5 composed of each layer and each part having the contact angle as described above, the fiber treatment agent described above is used for each layer, and the hot air blowing conditions in the air-through method described later, that is, What is necessary is just to control the temperature and air volume of hot air appropriately. In particular, it is used for the first layer 10 in order to reverse the hydrophilicity relationship between the first layer second portion 12 and the second layer first portion 21 with the nonwoven fabric 1B of the embodiment shown in FIG. When the fiber treatment agent is compared with the fiber treatment agent used for the second layer 20, the degree of hydrophilicity is set so that the fiber treatment agent used for the second layer 20 is lower. It is advantageous to choose. Moreover, the relationship of hydrophilicity between the 1st layer 2nd site | part 12 and the 2nd layer 1st site | part 21 is shown in FIG. 4 also by using the heat | fever extensible fiber mentioned later as a constituent fiber of the 2nd layer 20. FIG. It can be reversed with the nonwoven fabric 1B of the embodiment shown.

The air-through nonwoven fabric NW2, which is another preferred embodiment of the present invention, includes a thermoplastic fiber to which the fiber treatment agent is attached, and thus has a hydrophilicity along the thickness direction when viewed as a whole of the air-through nonwoven fabric. Has a slope. Specifically, the second layer is virtually divided into two in the thickness direction, and a portion closer to the first layer among the two divided portions is defined as a second layer first portion, When the part far from the layer is the second layer second part, the hydrophilicity of the first layer, the second layer first part, and the second layer second part is compared, and the following (21) and The relationship (22) is satisfied.
(21) The hydrophilicity of the first part of the second layer is higher than that of the first layer.
(22) The second layer second portion has a higher hydrophilicity than the second layer first portion.

In the air-through nonwoven fabric NW2, the magnitude relationship of the hydrophilicity between the first layer, the second layer first portion, and the second layer second portion is as follows: first layer <second layer first portion <second layer second portion It becomes. The degree of “hydrophilicity” referred to in the present invention is determined based on the contact angle of the fiber measured by the method described in [Method for measuring contact angle].

As described above, the air-through nonwoven fabric NW2 has higher hydrophilicity from the first layer to the second layer. In addition, the air-through nonwoven fabric NW2 has a higher hydrophilicity from the first part toward the second part in the second layer. Due to the fact that such a gradient is provided in the hydrophilicity in the thickness direction, when the liquid is supplied to the first surface side of the air-through nonwoven fabric NW2, the liquid quickly permeates through the nonwoven fabric. . Therefore, it is difficult for the liquid to flow along the surface on the first surface side. As a result, it is difficult for the liquid to remain on the surface on the first surface side, which is the surface supplied with the liquid. And the liquid which permeate | transmitted the air through nonwoven fabric of this invention becomes difficult to reverse. These remarkable effects become particularly remarkable when the air-through nonwoven fabric NW2 is used as a surface sheet of an absorbent article with the surface on the first layer side facing the skin.

FIG. 6 shows a specific example of the air-through nonwoven fabric NW2 having the above-described hydrophilicity gradient. The air-through nonwoven fabric 1D shown in the figure has a first layer 10 and a second layer 20. The first layer 10 and the second layer 20 are in direct contact with each other, and there are no other layers interposed between the two layers. The first layer 10 and the second layer 20 are each a single fiber layer, and are not composed of a multi-layer laminate that is further subdivided. The first layer 10 and the second layer 20 are bonded to each other on the entire area of the opposing surfaces, and no gap is generated between the both

layers

10 and 20. In addition, in FIG. 6, although the 1st layer 10 and the 2nd layer 20 are represented by the same thickness, this is because each

layer

10 and 20 was shown typically, and in actual air through nonwoven fabric 1D, The thickness of the first layer 10 and the second layer 20 may be different.

In the present invention, when the second layer 20 composed of a single layer is virtually divided into two equal parts in the thickness direction, the part closer to the first layer 10 is divided into the two parts divided into two parts. A portion far from the first layer 10 is called a second layer second portion 22. Since the second layer 20 is composed of a single layer, there is no boundary between the second part 21 and the second part 22. Further, the fibers constituting the second part 21 and the fibers constituting the second part 22 are the same.

In the second layer 20 of the nonwoven fabric 1D of the embodiment shown in FIG. 6, the hydrophilicity of the second part 22 is higher than that of the second part 21. In order to provide such a gradient of hydrophilicity in the second layer 20, it is preferable that the heat-fusible fiber to which the fiber treatment agent described above is attached is included in the second layer 20. In this case, the hydrophilicity of the second layer 20 may be gradually increased from the second part 21 toward the second part 22, or the hydrophilicity is stepped from the second part 21 toward the second part 22. The shape may be higher. From the viewpoint of improving the permeation of the liquid along the thickness direction, the hydrophilicity is preferably gradually increased from the second portion 21 toward the second portion 22. From the viewpoint of providing a gradient of hydrophilicity in which the hydrophilicity gradually increases, it is preferable that the heat-fusible fiber to which the fiber treatment agent described above is attached is included in the second layer 20.

Regardless of whether the degree of hydrophilicity is gradually increased or stepwise, in the second layer 20, the contact angle of water with respect to the fibers contained in the second layer first portion 21 is 50 degrees or more, particularly It is preferable that it is 60 degree | times 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 50 degrees or more and 80 degrees or less, and more preferably 60 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 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 30 degrees to 75 degrees, and more preferably 40 degrees to 70 degrees.

In contrast to the second layer 20 having a gradient in hydrophilicity, the first layer 10 has the same hydrophilicity in any part of the first layer 10. The hydrophilicity of the first layer 10 is lower than the hydrophilicity of the second layer first portion 21. Thus, the nonwoven fabric 1D of the present embodiment has a higher hydrophilicity in the order of the first layer 10, the second layer first portion 21, and the second layer second portion 22. The contact angle of water with respect to the fibers contained in the first layer 10 is 75 degrees or more, particularly 80 degrees or more, provided that the contact angle of water with respect to the fibers contained in the second layer first portion 21 is larger. Is preferably 90 degrees or less, and particularly preferably 85 degrees or less. For example, the contact angle of water with respect to the fibers contained in the first layer 10 is preferably 75 ° to 90 °, and preferably 80 ° to 85 °.

In order to form the first layer 10 having the same hydrophilicity at any part, for example, a fiber treating agent called an oil agent that has been conventionally used for imparting hydrophilicity to the fiber may be used. Typical examples of such fiber treatment agents include various surfactants. As the surfactant, anionic, cationic, zwitterionic and nonionic surfactants can be used. Examples of the surfactant include those described above as the surfactant used to make the second layer of the nonwoven fabric 1A have the same hydrophilicity at any part.

In addition, it is preferable that the constituent fibers of the first layer 10 are not treated with the above-described fiber treatment agent containing the components (A) to (C).

From the viewpoint of smoother liquid permeation from the first layer 10 to the second layer 20, the contact angle of water with the fibers contained in the first layer 10 and the water with respect to the fibers contained in the second layer first portion 21. The difference from the contact angle of the first layer 10 to the second layer first portion 21 is preferably 1 degree or more, particularly 10 degrees or more, more preferably 15 degrees or more, 40 degrees or less, particularly 30 degrees or less. Further, it is preferably 25 degrees or less. For example, the difference is preferably 1 to 40 degrees, more preferably 10 to 30 degrees, and more preferably 15 to 25 degrees.

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 10 and the contact angle of water with respect to the fibers contained in the second layer second portion 22 (first layer 10−second layer). The second part 22) is 2 degrees or more, particularly 10 degrees or more, and more preferably 20 degrees or more, provided that the contact angle difference between the first layer 10 and the second layer first part 21 is larger than that described above. It is preferably 60 ° or less, particularly 50 ° or less, and more preferably 35 ° or less. For example, the difference is preferably 2 degrees or more and 60 degrees or less, more preferably 10 degrees or more and 50 degrees or less, and more preferably 20 degrees or more and 35 degrees or less.

Next, the heat-fusible fiber to which the fiber treatment agent is attached, which is included in the air-through nonwoven fabrics NW1 and NW2, will be described. The heat-fusible fiber has a hydrophilicity on the surface of the fiber as a result of the fiber treatment agent adhering to the heat-fusible fiber, as compared to before the fiber treating agent is attached. The adhesion amount of the fiber treatment agent is preferably 0.1% by mass or more, more preferably from 0.1 to 10% from the viewpoint of increasing the hydrophilicity of the fiber, as a proportion of the total mass of heat-fusible fibers excluding the fiber treatment agent. The amount is 1.5% by mass, more preferably 0.2 to 1.0% by mass.

As the method for attaching the fiber treatment agent to the surface of the heat-fusible fiber, various known methods can be employed without any particular limitation. For example, application by spraying, application by a slot coater, application by roll transfer, immersion in a fiber treatment agent, and the like can be mentioned. These treatments may be performed on the fibers before being made into a web, or after the fibers are made into a web by various methods. However, it is necessary to perform processing before air-through processing described later. The fiber having the fiber treatment agent attached to the surface is dried at a temperature sufficiently lower than the melting point of the polyethylene resin (for example, 120 ° C. or less) by, for example, a hot air blowing type dryer.

Examples of the heat-fusible fiber include 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, and a hollow fiber. These fibers can be used alone or in combination of two or more. Of these fibers, it is particularly preferable to use a heat-fusible core-sheath composite fiber.

The heat-fusible fiber has a heat-fusible property before and after the fiber treatment agent is attached, and has a core-sheath type composite structure. 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. In particular, a concentric core-sheath type is preferable. Regardless of the form of the fibers, from the viewpoint of producing a flexible nonwoven fabric having good touch and the like, the fineness of the heat-fusible fiber is preferably 1.0 dtex or more and 10.0 dtex or less. More preferably, it is 0 dtex or more and 8.0 dtex or less.

The fineness of the heat-fusible fiber may be the same between the first layer 10 and the second layer 20, or may be different. When the fineness of the heat-fusible fiber in each of the

layers

10 and 20 is different, the fineness of the heat-fusible fiber contained in the second layer 20 is greater than the fineness of the heat-fusible fiber contained in the first layer 10. Is preferably small. By doing so, a gradient in which the capillary force increases from the first layer 10 toward the second layer 20 is generated, and this is combined with a gradient of hydrophilicity attributed to the fiber treatment agent, so that the second layer 10 has a second gradient. There is an advantageous effect that the drawability of the liquid toward the layer 20 is improved. However, in the present invention, since the gradient of the hydrophilicity attributed to the fiber treatment agent is sufficiently imparted, the first layer 10 can be used without using a heat-fusible fiber having a small fineness for the second layer 20. The drawability of the liquid toward the second layer 20 is sufficient.

Particularly preferable examples of the heat-fusible core-sheath type composite fiber include the core-sheath type composite fiber P described above. Moreover, the heat-fusible core-sheath conjugate fiber to which the fiber treatment agent is attached is a heat-extensible conjugate fiber. The configurations and preferred configurations of the core-sheath type composite fiber P and the heat-extensible composite fiber are also as described above.

In the present invention, as the heat-fusible fiber, a mixture of heat-extensible fiber and non-heat-extensible fiber may be used. The non-heat-extensible fiber is a bicomponent composite fiber that includes a high-melting component and a low-melting component, and the low-melting component is continuously present in the length direction on at least a part of the fiber surface. The form of the composite fiber (non-heat-extensible fiber) includes various forms such as a core-sheath type and a side-by-side type, and any form can be used. The heat-fusible composite fiber is drawn at the raw material stage. The term “stretching treatment” as used herein refers to a stretching operation with a stretching ratio of about 2 to 6 times. The mixing ratio of the heat-extensible fiber and the non-heat-extensible fiber is preferably 1: 9 to 9: 1 for the former: the latter and more preferably 4: 6 to 6: 4 in terms of mass ratio. Thereby, it becomes easier to recover the bulk of the nonwoven fabric with hot air, and an air-through nonwoven fabric having better touch and dryness than using each fiber alone can be obtained. Alternatively, heat-extensible fibers may be used for the first layer, non-heat-extensible fibers may be used for the second layer, heat-extensible fibers may be used for the second layer, and non-heat-extensible fibers may be used for the second layer. It may be used.

FIG. 7 shows a manufacturing apparatus suitably used for manufacturing the air-through nonwoven fabric NW1 and / or the air-through nonwoven fabric NW2. 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.

The first web production unit 110 and the second web production unit 120 are both constituted by a card machine. The 1st web manufacture part 110 is a site | part which manufactures the web corresponding to the 1st layer in the target air through 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 in the target air through 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 out from the first web production unit 110 and the second web production 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.

The superposed web 101 formed by integrating the

webs

111 and 122 in the embossed part 130 is conveyed to the air-through processing part 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 agent containing the components (A) to (C) is attached, the fiber of the fiber treatment agent according to the amount of heat received by the heat-fusible fiber. The degree of penetration into the interior is different. 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 this case, the fiber treatment agent is attached only to the heat-fusible fiber constituting the first web 111, and the normal fiber oil agent is attached to the heat-fusible fiber constituting the second web 122. And the gradient of hydrophilicity arises in the 1st layer 10 formed from the 1st web 111, and the air through nonwoven fabric 1 of the form shown in FIG. 3 is obtained. In addition, when a fiber treatment agent is attached to both the heat-fusible fiber constituting the first web 111 and the heat-fusible fiber constituting the second web 111, the first layer formed from the first web 111 is formed. 10 and the second layer 20 formed from the second web 122 cause a gradient of hydrophilicity, and the air-through

nonwoven fabric

1A or 1B having the form shown in FIG. 4 or 5 is obtained. Whether the air-through nonwoven fabric 1A or the air-through nonwoven fabric 1B is obtained is controlled by the type and amount of fiber treatment agent to be adhered to each heat-fusible fiber constituting the first web 111 and the second web 122. Can do. For example, the fiber treatment agent attached to the heat-fusible fiber constituting the second web 122 has a higher hydrophilicity than the fiber treatment agent attached to the heat-fusible fiber constituting the first web 111. In that case, the air-through nonwoven fabric 1A having the form shown in FIG. 4 is easily obtained. In addition to this, when the amount of hot air blowing is increased, the air-through nonwoven fabric 1A having the form shown in FIG. 4 is more easily obtained. On the other hand, when the hydrophilicity of the fiber treatment agent attached to the heat-fusible fiber constituting the first web 111 and the fiber treatment agent attached to the heat-fusible fiber constituting the second web 122 is low. Is easy to obtain the air-through nonwoven fabric 1B having the form shown in FIG.

Further, in the present 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. In particular, for the second web 122, the surface facing the first web 111 receives the largest amount of heat, and the surface facing the endless belt 142 receives the smallest amount of heat. As a result, if the fiber treatment agent is adhered to the heat-fusible fiber constituting the second web 122, the second web 122 is connected to the endless belt 142 from the surface facing the first web 111. The degree of penetration of the fiber treatment agent into the fibers decreases toward the opposite surface. As a result, the hydrophilicity of the second web 122 increases from the surface facing the first web 111 toward the surface facing the endless belt 142. Moreover, if a fiber oil agent having a lower hydrophilicity than the fiber treatment agent is used as the fiber oil agent to be adhered to the constituent fibers of the first web 111, the overlapping web 101 is moved from the first web 111 side to the second web 122 side. Since the hydrophilicity increases, the air-through nonwoven fabric 1D having the form shown in FIG. 6 is obtained as the air-through nonwoven fabric NW2.

Thus, the above method expresses a gradient of hydrophilicity by partially reducing the hydrophilicity of the heat-fusible fiber to which the fiber treatment agent has been applied by applying heat in the thickness direction of the nonwoven fabric. I am letting. 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.

In the air-through processing unit 140, as described above, a gradient of hydrophilicity occurs along the thickness direction of the overlapping web 101. At the same time, in the air-through processing section 140, heat-bonding of the constituent fibers of the overlapping web 101 occurs, and the target air-through nonwoven fabric 102 is obtained. The obtained air-through nonwoven fabric 102 exits from the air-through treatment unit 140 and is then introduced into the calendar unit 150 to be calendered. By the calendering process, the surface of the air-through nonwoven fabric 102 becomes smooth, and fuzzing and the like are reduced. Thereafter, the air-through nonwoven fabric 102 is wound up by the winding unit 160.

In the above manufacturing method, embossing by the embossed portion 130 may not be performed depending on circumstances. In that case, the obtained air-through nonwoven fabric 102 is smooth with no irregularities on the front and back surfaces. In contrast, when embossing by the embossed portion 130 is performed and a heat-extensible fiber is used as the heat-fusible fiber, a plurality of protrusions are formed on the surface due to the heat extension of the heat-extensible fiber. The air-through nonwoven fabric 102 having the above is obtained. The convex portion is formed in a region surrounded by the embossed fused portion. The convex portion has a shape protruding from the second layer side toward the first layer side. This is because the second web 122 corresponding to the second layer is in contact with the endless belt 142 during the air-through process, so that the extension of the extended heat-extensible fibers is regulated by the endless belt 142. On the other hand, there is no such restriction in the first web 111 corresponding to the first layer side. From this point of view, it is preferable that the heat-extensible fiber is contained in the first web 111 because it is easy to form a convex portion having a feeling of unevenness.

When the convex portion is formed on the air-through nonwoven fabric as described above, the convex portion has a high degree of hydrophilicity from the top to the bottom of the convex portion. The reason for this is as follows. An embossed fusion part is formed at the bottom of the convex part. Since the embossed fusion part is formed into a film or a fusion state close to that by the fusion of fibers, the air permeability is lowered. On the other hand, there is no portion that hinders air permeability at the top of the convex portion and in the vicinity thereof. As a result, in the air-through treatment, the hot air easily passes through the top of the convex portion and the vicinity thereof, and the hydrophilicity is likely to decrease. On the other hand, hot air does not easily pass through the embossed fusion, and the hydrophilicity is unlikely to decrease. As a result, the convex portion has a higher hydrophilicity from the top to the bottom.

The non-woven fabric of the present invention thus obtained may then be subjected to secondary processing. Examples of secondary processing include known three-dimensional shaping.

The nonwoven fabric of the present invention can be applied to various fields by utilizing 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, 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 finally obtained nonwoven fabric 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.

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 disposed between both sheets. As the absorbent body and the back sheet when the nonwoven fabric according to the present invention is used as the top sheet, materials usually used in the technical field can be used without any particular limitation.
For example, as the absorbent body, a fiber assembly made of a fiber material such as pulp fiber or a structure 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 depending on the specific application of the absorbent article. Such members are known to those skilled in the art. For example, when the absorbent article is applied 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.

As mentioned above, although this invention was demonstrated based on the preferable embodiment, this invention is not restrict | limited to embodiment mentioned above.
For example, the embossed portion forming pattern in the case of forming the embossed portion on the nonwoven fabric 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, in the manufacturing method of the nonwoven fabric shown in FIG. 2, when embossing is performed, an embossing roll and / or a flat roll can be heated, and the nonwoven fabric which the embossing part and / or the periphery hydrophilicity fell can also be manufactured. In addition, when the nonwoven fabric of the present invention is used for diapers, napkins, wipers, and other products, heat is applied to the desired part 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.

Regarding the embodiment described above, the present invention further discloses the following fibers or nonwoven fabrics.
<1>
A nonwoven fabric using heat-fusible fibers to which a fiber treatment agent is attached, wherein the fiber treatment agent comprises the following components (A), (B) and (C).
(A) polyorganosiloxane,
(B) an alkyl phosphate ester,
(C) Anionic surfactant represented by the following general formula (1)

<2>
<1 in which the polyorganosiloxane is contained in a proportion of 1% by mass or more, preferably 5% by mass or more, and 30% by mass or less, preferably 20% by mass or less, based on the total mass of the fiber treatment agent. > Non-woven fabric.
<3>
As described in <1> or <2>, the first surface of the nonwoven fabric has a second surface opposite to the first surface, and the hydrophilicity increases from the first surface side to the second surface side. Non-woven fabric.
<4>
The nonwoven fabric has a concavo-convex shape, the hydrophilicity is high from the top to the bottom of the convex part,
The difference between the contact angle of the top of the convex part and the contact angle of the bottom is preferably 2.5 degrees or more, more preferably 3 degrees or more, and even more preferably 5 degrees or more, The nonwoven fabric according to any one of <1> to <3>, preferably 10 degrees or less, more preferably 8 degrees or less, and even more preferably 7 degrees or less.
<5>
It has a thin part formed by embossing and a thick part other than that, the thin part or its vicinity is hydrophilic, and the top part of the thick part is the thickness The non-woven fabric according to any one of <1> to <4>, wherein the hydrophilicity is lower than that of the thin portion or the vicinity thereof.
<6>
The nonwoven fabric according to any one of <1> to <5>, which is an air-through nonwoven fabric.

<7>
The nonwoven fabric is an air-through nonwoven fabric,
The heat-fusible fiber has a first layer and a second layer adjacent to the first layer, and the fiber treatment agent is attached to at least one of the first layer and the second layer.
The first layer is virtually divided into two in the thickness direction, and of the two parts divided into two, the part far from the second layer is the first layer first part, and the side close to the second layer When the first layer second part is compared with the first layer first part, the first layer second part, and the second layer, the following (1) and (2) Satisfy the relationship,
(1) The first layer second part has higher hydrophilicity than the first layer first part,
(2) The hydrophilicity of any part of the second layer is higher than the second part of the first layer.
The nonwoven fabric according to any one of <1> to <6>.
<8>
The nonwoven fabric according to <7>, wherein the hydrophilicity of the second layer is the same in any part of the second layer.
<9>
<7> or <7> The contact angle of water with respect to the fibers contained in the first part of the first layer is preferably 70 degrees or more, particularly preferably 72 degrees or more, and preferably 85 degrees or less, particularly preferably 82 degrees or less. The nonwoven fabric according to 8>.
<10>
On the condition that the contact angle of water with respect to the fibers contained in the first layer second portion is smaller than the contact angle of water with respect to the fibers contained in the first layer first portion, preferably 50 degrees or more, More preferably 60 degrees or more, particularly preferably 65 degrees or more, 80 degrees or less, preferably 75 degrees or less, more preferably 70 degrees or less, and any one of the above <7> to <9> The nonwoven fabric described.
<11>
The non-woven fabric according to any one of <7> to <10>, wherein a contact angle of water with respect to fibers contained in the second layer is 20 degrees or greater and 75 degrees or less.
<12>
The contact angle of water with respect to the fibers contained in the second layer is preferably 20 ° or more, particularly preferably 30 ° or more, provided that the contact angle of water with respect to the fibers contained in the first portion of the first part is smaller. The nonwoven fabric according to any one of <7> to <11>, preferably 75 degrees or less, particularly preferably 65 degrees or less.
<13>
The difference between the contact angle of water with respect to the fibers contained in the first layer and the second portion and the contact angle of water with respect to the fibers contained in the second layer (first layer, second portion-second layer) is 1 degree or more, The nonwoven fabric according to any one of <7> to <12>, particularly preferably 10 degrees or more, more preferably 20 degrees or more, and preferably 50 degrees or less, particularly preferably 40 degrees or less.
<14>
The difference between the contact angle of water with respect to the fibers contained in the first portion of the first layer and the contact angle of water with respect to the fibers contained in the second layer (first layer, first portion-second layer) is the first layer first step. 2 degrees or more, particularly 10 degrees or more, more preferably 20 degrees or more, preferably 65 degrees or less, particularly 50 degrees or less, provided that the contact angle is larger than the difference between the contact angles of the two parts and the second layer. Preferred non-woven fabric according to any one of <7> to <13>.
<15>
The constituent fiber of the second layer 20 is the nonwoven fabric according to any one of the above <7> to <14>, which is not treated with the fiber treatment agent containing the components (A) to (C).

<16>
The second layer is virtually divided into two in the thickness direction. Of the two parts divided in half, the part closer to the first layer is defined as the first part, and the part far from the first layer is defined as the first part. When the second part is the second part, the second layer first part, the second layer first part, and the second layer second part are compared with each other, the following relationships (13) and (14) are satisfied. The nonwoven fabric as described in said <7>.
(13) The second layer first part has higher hydrophilicity than the first layer second part,
(14) The second layer second portion has a higher hydrophilicity than the second layer first portion.
<17>
In the second layer, the contact angle of water with respect to the fibers contained in the first part of the second layer is 50 degrees or more, preferably 55 degrees or more, more preferably 60 degrees or more, particularly preferably 65 degrees or more, and 80 The non-woven fabric according to the above <16>, which is not more than 75 degrees, preferably not more than 75 degrees, and more preferably not more than 70 degrees.
<18>
On the condition that the contact angle of water with respect to the fibers contained in the second layer second part is smaller than the contact angle of water with respect to the fibers contained in the second layer first part, preferably 20 degrees or more, The non-woven fabric according to <16> or <17>, more preferably 40 degrees or more and 70 degrees or less, preferably 65 degrees or less.
<19>
Difference between the contact angle of water with respect to the fibers contained in the second part of the first layer and the contact angle of water with respect to the fibers contained in the first part of the second layer (first layer second part-second layer first part) However, the nonwoven fabric according to any one of <16> to <18>, preferably 1 degree or more, particularly preferably 10 degrees or more, and preferably 30 degrees or less, particularly preferably 25 degrees or less.
<20>
The difference between the contact angle of water with respect to the fibers contained in the first part of the first layer and the contact angle of water with respect to the fibers contained in the second part of the second layer (first layer first part-second layer second part) However, on the condition that the contact angle difference between the second layer first part and the second layer first part is greater than 2 degrees, preferably 10 degrees or more, 65 degrees or less, particularly 50 degrees or less The nonwoven fabric according to any one of the above <16> to <19>, which is preferably

<21>
The second layer is virtually divided into two in the thickness direction. Of the two divided parts, the part closer to the first layer is defined as the first part, and the part far from the first layer is defined as the first part. When it is set as the second part, the hydrophilicity of the first layer first part, the first layer second part, the second layer first part, and the second layer second part is compared. , (16) and the nonwoven fabric according to <7> that satisfies the relationship of (17).
(15) The second layer first part has higher hydrophilicity than the first layer first part.
(16) The hydrophilicity of the first layer second portion is higher than that of the second layer first portion.
(17) The second layer second portion has higher hydrophilicity than the first layer second portion.
<22>
Difference between the contact angle of water with respect to the fibers contained in the first part of the second layer and the contact angle of water with respect to the fibers contained in the second part of the first layer (second layer first part-first layer second part) Is preferably 1 degree or more, particularly preferably 2 degrees or more, and preferably 30 degrees or less, particularly preferably 25 degrees or less.
<23>
The difference between the contact angle of water with respect to the fibers contained in the first part of the first layer and the contact angle of water with respect to the fibers contained in the second part of the second layer (first layer first part-second layer second part) Is preferably 2 ° or more, particularly preferably 5 ° or more, and 55 ° or less, particularly preferably 45 ° or less, according to the above <21> or <22>.
<24>
The first layer is the nonwoven fabric according to any one of <21> to <23>, wherein the hydrophilicity gradually increases from the first part toward the second part.

<25>
The nonwoven fabric according to any one of <7> to <24>, wherein the heat-fusible fiber to which the fiber treatment agent is attached is contained in a first layer.
<26>
The nonwoven fabric according to any one of <7> to <24>, wherein a heat-extensible fiber is used for the first layer and a non-heat-extensible fiber is used for the second layer.

<27>
The nonwoven fabric is an air-through nonwoven fabric,
The heat-fusible fiber has a first layer and a second layer adjacent to the first layer, and the fiber treatment agent is attached to at least one of the first layer and the second layer.
The second layer is virtually divided into two in the thickness direction, and the portion closer to the first layer of the two divided portions is the second layer first portion, and the side far from the first layer When the first layer, the second layer first portion, and the second layer second portion are compared with each other, the following (1) and (2) The nonwoven fabric according to any one of <1> to <6>, which satisfies a relationship.
(1) The hydrophilicity of the second layer first portion is higher than that of the first layer.
(2) The second layer second portion has a higher hydrophilicity than the second layer first portion.
<28>
In the second layer, the contact angle of water with respect to the fibers contained in the first part of the second layer is preferably 50 degrees or more, particularly preferably 60 degrees or more, and is preferably 80 degrees or less, particularly preferably 75 degrees or less. The contact angle of water with respect to the fibers contained in the first part of the second layer is preferably 50 degrees or greater and 80 degrees or less, and more preferably 60 degrees or greater and 75 degrees or less. .
<29>
The contact angle of water with respect to the fibers contained in the second part of the second layer is 30 degrees or more, particularly 40 degrees or more, provided that the contact angle of water with respect to the fibers contained in the second part of the first part is smaller. The nonwoven fabric according to any one of the above <27> or <28>, which is preferably 75 ° or less, particularly preferably 70 ° or less.
<30>
The nonwoven fabric according to any one of the above <27 to <29>, wherein the first layer has the same hydrophilicity in any part of the first layer.
<31>
The contact angle of water with respect to the fibers contained in the first layer is preferably 75 degrees or more, particularly preferably 80 degrees or more, on condition that the contact angle of water with respect to the fibers contained in the first part of the second layer is larger. The nonwoven fabric according to any one of <27> to <30>, preferably 90 degrees or less, particularly preferably 85 degrees or less.
<32>
The difference between the contact angle of water with respect to the fibers contained in the first layer and the contact angle of water with respect to the fibers contained in the first portion of the second layer (first layer 10 -second layer first portion 21) is 1 degree. In particular, it is preferably 10 ° or more, more preferably 15 ° or more, 40 ° or less, particularly preferably 30 ° or less, and further preferably 25 ° or less. The nonwoven fabric described.
<33>
The difference between the contact angle of water with respect to the fibers contained in the first layer and the contact angle of water with respect to the fibers contained in the second portion of the second layer (the first layer—the second portion of the second portion) is the first layer— 2 degrees or more, particularly 10 degrees or more, more preferably 20 degrees or more, preferably 60 degrees or less, particularly 50 degrees or less, more The nonwoven fabric according to any one of the above <27> to <32>, which is preferably 35 degrees or less.

<34>
The nonwoven fabric according to any one of <1> to <33>, wherein the fineness of the heat-fusible fiber contained in the second layer is smaller than the fineness of the heat-fusible fiber contained in the first layer.
<35>
The nonwoven fabric according to any one of <1> to <34>, wherein a heat-extensible fiber is used for the second layer and a non-heat-extensible fiber is used for the second layer.
<36>
The second layer is the nonwoven fabric according to any one of <16> to <35>, wherein the hydrophilicity gradually increases from the first part toward the second part.
<37>
The nonwoven fabric according to any one of <1> to <36>, wherein the heat-fusible fiber to which the fiber treatment agent is attached is included in a second layer.
<38>
<7> thru | or <37> which have multiple convex part which protruded toward the 1st layer side from the 2nd layer side, and in this convex part, hydrophilicity becomes high from the top part to the bottom part of this convex part. The nonwoven fabric according to any one of 1.
<39>
The nonwoven fabric according to any one of <1> to <19>, wherein the heat-fusible fiber is a heat-extensible fiber whose length is extended by heat.
<40>
Any of the above <1> to <39>, wherein the heat-fusible fiber contains titanium oxide in a proportion of 0.5% by mass or more and 5% by mass or less with respect to the total mass of the heat-fusible fiber. The nonwoven fabric according to 1.

<41>
The nonwoven fabric according to any one of <1> to <40>, wherein the polyorganosiloxane is polydimethylsiloxane.
<42>
In any one of the above items <1> to <41>, wherein the alkyl phosphate ester used as the component (B) is a completely neutralized or partially neutralized salt of a mono- or dialkyl phosphate ester having a carbon chain of 16 to 18 The nonwoven fabric described.
<43>
The nonwoven fabric according to any one of <1> to <42>, wherein the component (C) is a dialkylsulfonic acid or a salt thereof.
<44>
The nonwoven fabric according to the above <43>, wherein each of the two-chain alkyl groups of the dialkylsulfonic acid has 4 to 14, particularly 6 to 10, carbon atoms.
<45>
The nonwoven fabric according to any one of <1> to <44>, wherein the content ratio of the component (A) to the component (C) (the former: the latter) is 1: 3 to 4: 1 by mass ratio. .
<46>
The adhesion amount of the fiber treatment agent to the heat-fusible fiber is such that the ratio to the total mass of the heat-fusible fiber excluding the fiber treatment agent is 0.1% by mass or more, preferably 0.1 to 1.5 mass. %, More preferably 0.2 to 1.0% by mass, the nonwoven fabric according to any one of <1> to <45>.
<47>
The molecular weight of the polyorganosiloxane as component (A) is preferably 100,000 or more, more preferably 150,000 or more, still more preferably 200,000 or more, preferably 1,000,000 or less, more preferably 800,000 in terms of weight average molecular weight. The nonwoven fabric according to any one of <1> to <46>, more preferably 600,000 or less.
<48>
The nonwoven fabric according to any one of <1> to <47>, wherein two or more types of polyorganosiloxanes having different molecular weights are used as the polyorganosiloxane as the component (A).
<49>
(A) Two or more types of polyorganosiloxanes having different molecular weights are used as the component,
One of them has a weight average molecular weight of preferably 100,000 or more, more preferably 150,000 or more, still more preferably 200,000 or more, preferably 1,000,000 or less, more preferably 800,000 or less, still more preferably. Is less than 600,000,
The other type has a weight average molecular weight of preferably less than 100,000, more preferably 50,000 or less, more preferably 35,000 or less, still more preferably 20,000 or less, and preferably 2,000 or more, more The nonwoven fabric according to any one of <1> to <48>, preferably 3000 or more, more preferably 5000 or more.
<50>
The blending ratio (the former: latter) 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 preferably from 1:10 to 4: 1, more preferably by mass. Is the nonwoven fabric according to <49>, wherein the ratio is 1: 5 to 2: 1.

<51>
The blending ratio of the component (A) in the fiber treatment agent is preferably 1% by mass or more, more preferably 5% by mass or more, and 30% by mass with respect to the total mass of the fiber treatment agent. The non-woven fabric according to any one of the above items <1> to <50>, preferably 20% by mass or less.
<52>
The blending ratio of the component (B) in the fiber treatment agent is preferably 5% by mass or more, more preferably 10% by mass or more, and preferably 30% by mass or less, more preferably 25% by mass or less. The nonwoven fabric according to any one of <1> to <51>.
<53>
The blending ratio of the component (C) in the fiber treatment agent is preferably 1% by mass or more, more preferably 5% by mass or more, preferably 20% by mass or less, more preferably 13% by mass or less. The nonwoven fabric according to any one of <1> to <52>.
<54>
The content ratio (the former: latter) of the polyorganosiloxane as the component (A) and the anionic surfactant as the component (C) in the fiber treatment agent is preferably 1: 3 to 4: 1 by mass ratio, The nonwoven fabric according to any one of <1> to <53>, more preferably 1: 2 to 3: 1.
<55>
The content ratio (the former: latter) of the polyorganosiloxane of component (A) and the alkyl phosphate ester of component (B) in the fiber treatment agent is preferably 1: 5 to 10: 1 by mass ratio, The nonwoven fabric according to any one of <1> to <54>, more preferably 1: 2 to 3: 1.
<56>
The heat-fusible fiber includes a heat-extensible fiber composed of a heat-extensible composite fiber having a first resin component that constitutes a core portion and a second resin component that constitutes a sheath portion,
The heat-extensible conjugate fiber preferably has a thermal elongation rate of 0.5% to 20% 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) The nonwoven fabric according to any one of <1> to <55>, more preferably 3% to 20%, and still more preferably 5.0% to 20%.
<57>
An absorbent article using the nonwoven fabric according to any one of <1> to <56>.
<58>
The absorbent article according to <57>, which is a sanitary napkin.

<59>
A fiber treatment agent for nonwoven fabric containing the following component (A), component (B) and component (C), wherein the content ratio of the component (A) to the component (C) (the former: the latter) is mass. The fiber treatment agent for nonwoven fabrics having a ratio of 1: 3 to 4: 1 and containing the component (A) in a proportion of 1% by mass to 30% by mass with respect to the mass of the fiber treatment agent.
(A) polyorganosiloxane,
(B) an alkyl phosphate ester,
(C) Anionic surfactant represented by the following general formula (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 ₁ and R ₂ 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. , X represents —SO ₃ M, —OSO ₃ M or —COOM, and M represents H, Na, K, Mg, Ca or ammonium.)
<60>
The fiber treatment agent for nonwoven fabrics according to <59>, wherein the polyorganosiloxane is polydimethylsiloxane.
<61>
The polydimethylsiloxane is composed of two or more types of polydimethylsiloxane, one of which is composed of polydimethylsiloxane having a weight average molecular weight of 100,000 or more, and the other is composed of polydimethylsiloxane having a weight average molecular weight of less than 100,000. <59> or <60> The fiber treatment agent for nonwoven fabrics described in the above.
<62>
A preferable blending ratio (the former: latter) 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 preferably a mass ratio of 1:10 to 4: 1. The fiber treatment agent for nonwoven fabrics according to <61>, preferably in the range of 1: 5 to 2: 1.
<63>
Any one of the above <59> to <62>, wherein the alkyl phosphate used as the component (B) is a completely neutralized or partially neutralized salt of a mono- or dialkyl phosphate having a carbon chain of 16 to 18 The fiber treatment agent for nonwoven fabrics as described.
<64>
The blending ratio of the component (B) in the fiber treatment agent is 5% by mass or more, preferably 10% by mass or more, and 30% by mass or less, preferably 25% by mass or less. > The fiber processing agent for nonwoven fabrics of any one of>.
<65>
The fiber treatment agent for nonwoven fabric according to any one of <59> to <64>, wherein the component (C) is a dialkylsulfonic acid or a salt thereof.
<66>
The fiber treatment agent for nonwoven fabrics according to <65>, wherein the number of carbon atoms in each of the two-chain alkyl groups of the dialkylsulfonic acid is preferably 4 to 14, particularly 6 to 10.
<67>
<59> thru | or the mixture ratio of the said (C) component in the said fiber processing agent is 1 mass% or more, Preferably it is 5 mass% or more, and is 20 mass% or less, Preferably it is 13 mass% or less. The fiber treatment agent for nonwoven fabrics according to any one of <67>.
<68>
The content ratio of the polyorganosiloxane of the component (A) and the anionic surfactant of the component (C) in the fiber treatment agent is preferably a mass ratio of 1: 3 to 4: 1, more preferably 1 The fiber treatment agent for nonwoven fabrics according to any one of the above items <59> to <67>, which is from 2 to 3: 1.
<69>
The content ratio of the polyorganosiloxane of the component (A) and the alkyl phosphate ester of the component (B) in the fiber treatment agent is 1: 4 to 3: 1, preferably 1: 2 to mass ratio. The fiber treatment agent for nonwoven fabrics according to any one of the above items <59> to <68>, which is 2: 1.

<70>
A heat-fusible fiber to which the fiber treatment agent according to any one of <59> to <69> is attached.
<71>
The adhesion amount of the fiber treatment agent is such that the ratio to the total mass of the heat-fusible fiber excluding the fiber treatment agent is 0.1% by mass or more, preferably 0.1 to 1.5% by mass, and more preferably. The heat-fusible fiber according to the above <70>, wherein is 0.2 to 1.0% by mass.
<72>
The contact angle with respect to water is 90 degrees or less, preferably 85 degrees or less, 60 degrees or more, preferably 65 degrees or more, 65 to 85 degrees, preferably 70 to 80 degrees <70 > Or <71>.
<73>
The heat-fusible fiber according to any one of <70> to <72>, wherein the heat-fusible fiber is a heat-extensible fiber.
<74>
The heat stretchable fiber is a heat stretchable conjugate fiber having a first resin component constituting a core portion and a second resin component constituting a sheath portion, and the heat stretchable conjugate fiber is a second resin component. The thermal elongation at a temperature 10 ° C. higher than the melting point (softening point in the case of a resin having no melting point) is 0.5 to 20%, preferably 3 to 20%, more preferably 5.0 to 20%. The heat-fusible fiber according to any one of the above <70> to <73>.
<75>
Any of the above <70> to <74>, wherein the heat-fusible fiber contains titanium oxide in a ratio of 0.5 mass% to 5 mass% with respect to the total mass of the heat-fusible fiber. The heat-fusible fiber according to 1.

<76>
A non-woven fabric using the heat-fusible fiber according to any one of <70> to <75>.
<77>
The nonwoven fabric according to <76>, wherein the heat-extensible fiber and the non-heat-extensible fiber are mixed as the heat-fusible fiber.
<78>
The nonwoven fabric according to <76> or <78>, which is an air-through nonwoven fabric.
<79>
The web or nonwoven fabric containing the heat-fusible fiber to which the fiber treatment agent according to any one of the above items <59> to <69> is attached is subjected to heat treatment, and the hydrophilicity of a part of the web or the nonwoven fabric is imparted. A method for producing a nonwoven fabric, wherein a reduced nonwoven fabric is obtained.
<80>
The web or nonwoven fabric containing the heat-fusible fiber to which the fiber treatment agent according to any one of the above items <59> to <79> is attached is subjected to heat treatment, and the hydrophilicity of a part of the web or the nonwoven fabric is imparted. A method for controlling the hydrophilicity of a nonwoven fabric to be lowered.

Hereinafter, the present invention will be described in more detail with reference to examples. However, the scope of the present invention is not limited to such examples. Unless otherwise specified, “%” means “mass%”.
[Example 1]
(1) Manufacture of a fiber whose hydrophilicity is lowered by heat A heat-fusible, heat-fusible, core-sheath type composite fiber having a core part made of polypropylene resin and a sheath part made of polyethylene resin is described below. It was immersed in the fiber treatment agent (oil agent) A of the composition. After the immersion, drying was performed to obtain a heat-fusible core-sheath composite fiber to which a fiber treatment agent was adhered. The amount of the oil agent attached to the fiber was 0.39% by mass.

(Composition of fiber treatment agent A)
Polyorganosiloxane (component (A), silicone “KM-903” manufactured by Shin-Etsu Silicone): 8.3% by mass
(Composition of silicone “KM-903”)
-Polydimethylsiloxane having a weight average molecular weight of about 500,000: 18% by mass
-Polydimethylsiloxane having a weight average molecular weight of about 20,000: 42% by mass
・ Dispersant: 5% by mass
・ Water: 35% by mass
Alkyl phosphate potassium salt [the component (B), manufactured by Kao Corporation, neutralized potassium hydroxide of gripper 4131]: 22.9% by mass
Dialkylsulfosuccinate sodium salt [component (C), manufactured by Kao Corporation, Perex OT-P]: 9.2% by mass
Alkyl (stearyl) betaine [components other than the above (A) to (C), manufactured by Kao Corporation, Anhitol 86B]: 13.8% by mass
Polyoxyethylene (number of moles added: 2) stearylamide [components other than the above (A) to (C), manufactured by Kawaken Fine Chemicals, Amizole SDE]: 27.5% by mass
Polyoxyethylene, polyoxypropylene, modified silicone [components other than the above (A) to (C), manufactured by Shin-Etsu Chemical Co., Ltd., X-22-4515]: 18.3 mass%

In Table 1, the blending amount of component (A) is the blending amount of silicone alone in the composition of “KM-903” described above, not the blending amount of “KM-903” as a whole. That is, the blending ratio of each component of the fiber treatment agent shown in Table 1 is a value calculated by excluding the dispersant and water in KM-903.

(2) Manufacture of nonwoven fabric Using the obtained fiber, the nonwoven fabric was manufactured by the method shown in FIG. 2 without using a non-heat-extensible fiber. A specific manufacturing method is as follows. First, the web formed using the card machine was embossed. The embossing was performed such that a grid-like embossed part was formed and the area ratio of the embossed part (compressed part) was 22%. The embossing processing temperature was 110 ° C. Next, air-through processing was performed. In the air-through process, heat treatment was performed once by blowing hot air from the embossed surface side in the embossing process. The heat treatment temperature for air-through processing was 136 ° C.
The obtained nonwoven fabric has a thin portion (embossed portion) 18 and a thick portion 19 other than that, as shown in FIGS. The concave and convex surface 10b having a large undulation and the other surface are a substantially flat surface 10a.

[Example 2]
A nonwoven fabric of Example 2 was obtained in the same manner as in Example 1 except that the blending ratio of each component of the fiber treatment agent A (oil agent) was changed to the ratio shown in Table 1.
Example 3
A nonwoven fabric of Example 3 was obtained in the same manner as in Example 1 except that the blending ratio of each component of the fiber treatment agent A (oil agent) was changed to the ratio shown in Table 1.
Example 4
A nonwoven fabric of Example 4 was obtained in the same manner as in Example 1 except that the blending ratio of each component of the fiber treatment agent A (oil agent) was changed to the ratio shown in Table 1.

Example 5
Example in which only a non-heat-extensible fiber having a core portion made of a polyester resin and a sheath portion made of a polyethylene resin was used as the heat-fusible fiber instead of the heat-extensible heat-fusible core-sheath type composite fiber. In the same manner as in Example 1, a nonwoven fabric of Example 5 was obtained.
Example 6
Example in which only a non-heat-extensible fiber having a core portion made of a polyester resin and a sheath portion made of a polyethylene resin was used as the heat-fusible fiber instead of the heat-extensible heat-fusible core-sheath type composite fiber. In the same manner as in Example 2, a nonwoven fabric of Example 6 was obtained.

Example 7
Implemented except that instead of heat-extensible heat-fusible core-sheath type composite fiber, only non-heat-stretchable fiber consisting of polyester resin in the core and polyethylene resin in the sheath was used as the heat-fusible fiber A nonwoven fabric of Example 7 was obtained in the same manner as Example 3.
Example 8
Example in which only a non-heat-extensible fiber having a core portion made of a polyester resin and a sheath portion made of a polyethylene resin was used as the heat-fusible fiber instead of the heat-extensible heat-fusible core-sheath type composite fiber. In the same manner as in Example 4, the nonwoven fabric of Example 8 was obtained.

Example 9
As the heat-fusible fiber, in place of the heat-extensible heat-fusible core-sheath type composite fiber, the heat-fusible core-sheath type composite fiber used in Example 1 and the non-heat-stretching used in Example 5 What was mixed with the active fiber at a mass ratio of 1: 1 was used. Specifically, the fiber treatment agent A is immersed in the heat-extensible fiber and the non-heat-extensible fiber, and the fiber treatment agent A is adhered so that the amount of adhesion per gram is the same. It was produced by blending fibers. A nonwoven fabric of Example 9 was obtained in the same manner as Example 1 except that the heat-fusible fiber was used.
Example 10
As the heat-fusible fiber, in place of the heat-extensible heat-fusible core-sheath type composite fiber, the heat-fusible core-sheath type composite fiber used in Example 1 and the non-heat-stretching used in Example 5 What was mixed with the active fiber at a mass ratio of 1: 1 was used. Specifically, the heat-extensible fibers and non-heat-extensible fibers were soaked with the content ratios of the components of the fiber treatment agent A (oil agent) changed to the ratios shown in Table 1, and each of them per 1 g. After attaching the said fiber treatment agent so that the adhesion amount might become the same, it produced by mixing those fibers. A nonwoven fabric of Example 10 was obtained in the same manner as Example 1 except that the heat-fusible fiber was used.

[Comparative Examples 1 and 2]
The nonwoven fabrics of Comparative Examples 1 and 2 were obtained in the same manner as in Example 1 except that the content ratio of each component of the fiber treatment agent A (oil agent) was changed to the ratios shown in Table 1. Specifically, the fiber treatment agent that does not contain the component (A) in Comparative Example 1 and the component (C) in Comparative Example 2 was used.

[Comparative Examples 3 and 4]
The nonwoven fabrics of Comparative Examples 3 and 4 were obtained in the same manner as in Example 5 except that the content ratio of each component of the fiber treatment agent A (oil agent) was changed to the ratio shown in Table 1. Specifically, in Comparative Example 3, the component (A) was used, and in Comparative Example 4, the fiber treatment agent not containing the component (C) was used.

[Method of measuring the amount of fiber treatment agent attached]
The adhesion amount of the fiber treatment agent was measured using a rapid residual oil extractor. 2 g of fiber was measured and placed in a predetermined container with a small hole at the bottom. After that, press the fiber with the lid to push the fiber into the lower part of the container, put 10cc ethanol / methanol (1: 1) mixed solution into it, let it stand for 10 minutes, put on the lid again, The ethanol / methanol component contained in the fiber was squeezed by pouring and the liquid was put into a weighing dish. The solvent was blown off by heating the weighing pan, and the amount of the fiber treatment agent adhered was measured by measuring the weight after heating from the original weight of the weighing pan. N = 3 was measured, and the average was defined as the oil adhesion amount.

[Evaluation]
[Contact angle]
For the nonwoven fabrics obtained in Examples 1 to 10 and Comparative Examples 1 to 4, the contact angle of water with the fibers taken out from the nonwoven fabric was measured. The results are shown in Table 1. For the nonwoven fabrics obtained in Examples 1 to 8 and Comparative Examples 1 to 4, the contact angle of water with respect to the fibers taken out from the nonwoven fabric was determined by the method described in paragraph [0057] of JP2010-168715A. Specifically, it was measured by the method described in [Measuring method of contact angle].
Moreover, about the nonwoven fabric obtained in Example 9 and 10, the heat | fever extensible fiber and the non-heat extensible fiber were extract | collected by the following method from the "convex part top part P1" and "back surface P2" of each nonwoven fabric, respectively, and extract | collected The contact angle of water with respect to each heat-extensible fiber and each non-heat-extensible fiber was measured by the same method.

[Method of collecting heat-extensible fibers and non-heat-extensible fibers]
From the blended nonwoven fabric, each fiber was cut from the outermost layer portion of the nonwoven fabric with a fiber length of 1 mm using precision scissors and tweezers and taken out from the nonwoven fabric.

In Table 1, the “convex portion top portion P1” in the “contact angle” column is the top portion P1 of the convex portion 119 of the uneven surface 10b (the top portion of the thick portion), and the “back surface P2” is the convex portion on the flat surface 10a. It is a measurement result of the contact angle with the distilled water of the fiber taken out from the nonwoven fabric in the site | part P2 corresponding to the top part P1. The contact angle measurement results of Examples 1 and 2 and Comparative Example 1 are shown in FIG.

[Remaining amount of surface sheet liquid]
The surface sheet is removed from a commercially available sanitary napkin (trade name “Laurier Sarah Cushion Skin Clean Absorption”) of Kao Corporation, and each of the nonwoven fabrics of Examples 1 to 10 and Comparative Examples 1 to 4 is laminated instead. The sanitary napkin for evaluation was obtained by fixing the periphery. Each nonwoven fabric was arranged with the back surface P2 side facing the absorber side.
On the surface of the sanitary napkin, an acrylic plate having a transmission hole with an inner diameter of 1 cm is overlapped, and a constant load of 100 Pa is applied to the napkin. Under such a load, 6.0 g of defibrinated horse blood is poured from the permeation hole of the acrylic plate. The acrylic plate is removed 60 seconds after pouring the horse blood, and then the weight (W2) of the nonwoven fabric is measured. The difference from the weight (W1) of the nonwoven fabric before pouring horse blood is measured in advance. (W2-W1) 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. The results are shown in Table 1.

[Wetback amount]
The surface sheet is removed from a commercially available sanitary napkin (trade name “Laurier Sarah Cushion Skin Clean Absorption”) of Kao Corporation, and each of the nonwoven fabrics of Examples 1 to 10 and Comparative Examples 1 to 4 is laminated instead. The sanitary napkin for evaluation was obtained by fixing the periphery. Each nonwoven fabric was arranged with the back surface P2 side facing the absorber side.
On the surface of the sanitary napkin, an acrylic plate having a transmission hole with an inner diameter of 1 cm is overlapped, and a constant load of 100 Pa is applied to the napkin. Under such a load, a total of 9.0 g of defibrinated horse blood is poured every 3.0 minutes from the permeation hole of the acrylic plate. The acrylic plate is removed 300 seconds after pouring the horse blood, and then a tissue paper is placed on the surface of the nonwoven fabric, and further, a weight is placed on the tissue paper, and a load of 2000 Pa is 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 ) (W4−W3). The above operation is performed three times, and the average value of the three times is defined as a liquid return amount (mg). The smaller the liquid return amount, the higher the evaluation. The results are shown in Table 1.

[Liquid flow distance]
The surface sheet is removed from a commercially available sanitary napkin (trade name “Laurier Sarah Cushion Skin Clean Absorption”) of Kao Corporation, and each of the nonwoven fabrics of Examples 1 to 10 and Comparative Examples 1 to 4 is laminated instead. The sanitary napkin for evaluation was obtained by fixing the periphery. Each nonwoven fabric was arranged with the back surface P2 side facing the absorber side.
The test apparatus has a mounting portion in which the mounting surface of the napkin is inclined 45 ° with respect to the horizontal plane. A napkin is placed on the placement portion so that the topsheet faces upward. As a test solution, colored distilled water is dropped onto the napkin at a rate of 1 g / 10 sec. First, the distance from the point where the nonwoven fabric gets wet to the point where the test liquid is first absorbed by the absorbent is measured. The above operation is performed three times, and the average of the three times is defined as the liquid flow distance (mm). The liquid flow distance is an index of the amount that the liquid touches the wearer's skin without being absorbed by the sanitary napkin. The shorter the liquid flow distance, the higher the evaluation.

[Bulk recoverability of nonwoven fabric]
The bulk recoverability of the nonwoven fabric was evaluated by the following method, and the results are shown in Table 1.
About the measuring method of the thickness of a nonwoven fabric, it carried out by the method as described in WO20110074207A1. For evaluation of the bulk recovery property, it was wound around a paper tube having an outer diameter of 85 mm in a roll shape with a length of 2700 m, then stored at room temperature for 2 weeks, and the rolled nonwoven fabric was fed out at a conveyance speed of 150 m / min and processed. The nonwoven fabric thickness is recovered by blowing hot air onto the nonwoven fabric at a temperature of 115 ° C. for a treatment time of 0.2 seconds and a wind speed of 2.8 m / second. The recoverability of the nonwoven fabric is when the thickness of the convex portion of the nonwoven fabric before wrapping the nonwoven fabric in a roll shape (thickness before storage) is C, and the thickness of the convex portion of the nonwoven fabric after blowing hot air (thickness after recovery) is D. Is represented by the following formula (2). The thickness of the nonwoven fabric after the hot air is sprayed is measured 1 minute to 1 hour after the hot air is sprayed. The thickness of the nonwoven fabric is measured by the method described above.
Bulk recoverability (%) = (D / C) × 100 (2)
C when the bulk recovery calculated by the formula (2) is less than 60%, B when it is 60% or more and less than 70%, A when 70% or more and less than 80%, and S when it is 80% or more. And evaluate. The higher the bulk recovery value, the higher the evaluation.

From the results shown in Table 1 and FIG. 3, in Examples 1 to 10 containing the components (A) to (C), Comparative Examples 1 and 3 not containing the component (A) and (C ) It can be seen that the difference in hydrophilicity between the convex portion top portion P1 and the back surface P2 is larger than in Comparative Examples 2 and 4 which do not contain the component. Further, from the evaluation results of the remaining amount of liquid shown in Table 1, the hydrophilic gradient obtained in Comparative Examples 1 and 2 was obtained by using the nonwoven fabric having a large hydrophilic gradient obtained in Examples 1 to 10 for the surface sheet. As compared with the case of using a relatively small non-woven fabric, it can be seen that the liquid residue and the wetback amount on the surface of the surface sheet are reduced, and the absorbability is improved.
From the results shown in Table 1, it can be seen that in Examples 1 to 10, although the content of the component (A) is small, the liquid flow distance is short.

As is clear from the results shown in Table 1, Examples 5 and 6 using non-heat-extensible fibers as the heat-fusible fibers had good touch. Further, the amount of liquid remaining on the surface was larger than that of Examples 1 and 2, but smaller than that of Comparative Examples 3 and 4, and was sufficiently satisfactory.
Examples 9 and 10 using a mixture of heat-extensible fibers and non-heat-extensible fibers as the heat-fusible fibers, as is clear from the results shown in Table 1, have a good touch and have a surface The liquid residue has decreased.

[Examples 11 to 14]
The air through nonwoven fabric of the form shown in FIG. 3 was manufactured using the manufacturing apparatus 100 shown in FIG. However, embossing by the embossed portion 130 was not performed. Table 2 below shows the raw material fibers of the first web 111 supplied to the first web manufacturing unit 110 of the manufacturing apparatus 100 and the raw material fibers of the second web 122 supplied to the second web manufacturing unit 120. The table also describes the composition of the fiber treatment agent applied to each raw fiber. The temperature of hot air in the air-through treatment section was set to 136 ° C., and the wind speed was set to 0.8 m / sec. Thus, an air-through nonwoven fabric having a two-layer structure having the basis weight shown in the table was obtained.

The heat-fusible fiber of the first web shown in Table 2 is a concentric core-sheath type composite fiber in which the core is polyethylene terephthalate and the sheath is polyethylene, and the mass ratio of the core to the sheath is the core: sheath = The fineness was 3.3 dtex and the fiber length was 51 mm. Further, the heat-fusible fiber of the second web shown in the same table is a concentric core-sheath type composite fiber in which the core is polyethylene terephthalate and the sheath is polyethylene, and the mass ratio of the core to the sheath is the core: Sheath = 50: 50, the fineness was 2.4 dtex, and the fiber length was 51 mm. The heat-extensible fiber shown in the table is a concentric core-sheath type composite fiber whose core is polyethylene terephthalate and whose sheath is polyethylene, and the mass ratio of the core to the sheath is core: sheath = 50: 50. The fineness was 4.2 dtex and the fiber length was 44 mm. The thermal expansion ratio of the core resin at the melting point + 10 ° C. was 9.5%.

The fiber treatment agents shown in Table 2 are as shown in Table 6 below. In Table 2, the blending amount of component (A) is the blending amount of silicone alone in the composition of “KM-903” of component (A) shown in Table 6, and the total amount of “KM-903” It is not a blending amount (the same applies to Tables 3 to 5 below).

Examples 15 and 16
The air through nonwoven fabric of the form shown in FIG. 4 was manufactured using the manufacturing apparatus 100 shown in FIG. However, embossing by the embossed portion 130 was not performed. Table 3 below shows the raw fibers of the first web 111 supplied to the first web manufacturing section 110 of the manufacturing apparatus 100 and the raw fibers of the second web 122 supplied to the first web manufacturing section 110. The table also describes the composition of the fiber treatment agent applied to each raw fiber. The fibers and fiber treatment agents shown in the table are the same as those in Examples 1 to 4 described above. The temperature of hot air in the air-through treatment section was set to 136 ° C., and the wind speed was set to 0.8 m / sec. Except this, it carried out similarly to Example 1, and obtained the air through nonwoven fabric of the 2 layer structure which has the basic weight shown to the same table | surface.

Example 17
The air through nonwoven fabric of the form shown in FIG. 5 was manufactured using the manufacturing apparatus 100 shown in FIG. However, embossing by the embossed portion 130 was not performed. Table 4 below shows the raw fibers of the first web 111 supplied to the first web manufacturing section 110 of the manufacturing apparatus 100 and the raw fibers of the second web 122 supplied to the first web manufacturing section 110. The table also describes the composition of the fiber treatment agent applied to each raw fiber. The fibers and fiber treatment agents shown in the table are the same as those in Examples 1 to 4 described above. The temperature of hot air in the air-through treatment section was set to 136 ° C., and the wind speed was set to 0.8 m / sec. Except this, it carried out similarly to Example 1, and obtained the air through nonwoven fabric of the 2 layer structure which has the basic weight shown to the same table | surface.

[Comparative Examples 5 and 6]
The air through nonwoven fabric of the form shown in FIG. 9 was manufactured using the manufacturing apparatus 100 shown in FIG. However, embossing by the embossed portion 130 was not performed. Table 5 below shows the raw material fibers of the first web 111 supplied to the first web manufacturing unit 110 of the manufacturing apparatus 100 and the raw material fibers of the second web 122 supplied to the second web manufacturing unit 120. The table also describes the composition of the fiber treatment agent applied to each raw fiber. The fibers and fiber treatment agents shown in the table are the same as those in Examples 11 to 14 described above. The temperature of hot air in the air-through treatment section was set to 136 ° C., and the wind speed was set to 0.8 m / sec. Except this, it carried out similarly to Example 1, and had the basic weight shown to the same table | surface, and obtained the air through nonwoven fabric of the 2 layer structure of the 1st layer 10 and the 2nd layer 20.

[Examples 18 to 21]
The air through nonwoven fabric of the form shown in FIG. 6 was manufactured using the manufacturing apparatus 100 shown in FIG. However, embossing by the embossed portion 130 was not performed. Table 6 below shows the raw fibers of the first web 111 supplied to the first web manufacturing section 110 of the manufacturing apparatus 100 and the raw fibers of the second web 122 supplied to the second web manufacturing section 120. The table also describes the composition of the fiber treatment agent applied to each raw fiber. The temperature of hot air in the air-through treatment section was set to 136 ° C., and the wind speed was set to 0.8 m / sec. Thus, an air-through nonwoven fabric having a two-layer structure having the basis weight shown in the table was obtained.

The heat-fusible fiber of the first web shown in Table 6 is a concentric core-sheath type composite fiber in which the core is polyethylene terephthalate and the sheath is polyethylene, and the mass ratio of the core to the sheath is the core: sheath = The fineness was 3.3 dtex and the fiber length was 51 mm. Further, the heat-fusible fiber of the second web shown in the same table is a concentric core-sheath type composite fiber in which the core is polyethylene terephthalate and the sheath is polyethylene, and the mass ratio of the core to the sheath is the core: Sheath = 50: 50, the fineness was 2.4 dtex, and the fiber length was 51 mm. The heat-extensible fiber shown in the table is a concentric core-sheath type composite fiber whose core is polyethylene terephthalate and whose sheath is polyethylene, and the mass ratio of the core to the sheath is core: sheath = 50: 50. The fineness was 3.3 dtex, and the fiber length was 44 mm. The thermal expansion ratio of the core resin at the melting point + 10 ° C. was 9.5%.

The fiber treatment agents shown in Table 6 are as shown in Table 7 below. In Table 6, the blending amount of component (A) is the blending amount of silicone alone in the composition of “KM-903” of component (A) shown in Table 7, and the total amount of “KM-903” It is not a compounding amount.

[Comparative Examples 7 and 8]
The air through nonwoven fabric of the form shown in FIG. 6 was manufactured using the manufacturing apparatus 100 shown in FIG. However, embossing by the embossed portion 130 was not performed. Table 6 below shows the raw fibers of the first web 111 supplied to the first web manufacturing section 110 of the manufacturing apparatus 100 and the raw fibers of the second web 122 supplied to the second web manufacturing section 120. The table also describes the composition of the fiber treatment agent applied to each raw fiber. The fibers and fiber treatment agents shown in the table are the same as those in Examples 18 to 21 described above. Nonwoven fabrics of Comparative Examples 7 and 8 were obtained in the same manner as in Example 18 except that the content ratio of each component of the fiber treatment agent was changed to the ratio shown in Table 6. Specifically, the fiber treatment agent not containing the component (A) in Comparative Example 7 and the component (C) in Comparative Example 8 was used. The temperature of hot air in the air-through treatment section was set to 136 ° C., and the wind speed was set to 0.8 m / sec. Except this, it carried out similarly to Example 18, and obtained the air through nonwoven fabric of the 2 layer structure which has the basic weight shown to the same table | surface.

[Evaluation]
As an example of the absorbent article, the diaper for infants (made by Kao Corporation: Mary's Sarasara Air-Through (registered trademark) M size manufactured in 2013) was removed from the surface sheet, and a non-woven fabric specimen (hereinafter referred to as a nonwoven fabric specimen) was used instead. And using a baby diaper for evaluation obtained by fixing the periphery. About the diaper obtained in this way, the liquid remaining amount on the top sheet and the liquid flow distance on the top sheet were measured by the following method. For Example 17 and Comparative Examples 5 and 6, in addition to these evaluations, the liquid return amount and the liquid absorption amount were measured by the following methods. For Examples 18 to 21 and Comparative Examples 7 and 8, in addition to the evaluation of the remaining liquid amount on the top sheet and the liquid flow distance on the top sheet, the liquid return amount and the liquid absorption amount were determined by the following methods. It was measured. These results are shown in Tables 2 to 6 below.

[Liquid remaining amount on top sheet]
40g of artificial urine is injected at a rate of 5g / sec using an infusion pump at a position of 155mm from the tip of the ventral portion in the longitudinal direction of the core wrap sheet covering the absorbent core of the diaper. Then, it was allowed to stand for 10 minutes, and then 40 g of artificial urine was injected and absorbed. Such artificial urine injection operation was repeated four times, and a total of 160 g of artificial urine was absorbed in the diaper. After standing for 10 minutes from the completion of the injection, the 10 cm × 10 cm surface sheet is peeled off around the injection point, and the mass (W2) is measured. Then, the surface sheet was dried at 105 ° C. for 1 hour using a dryer, the mass (W1) was measured, and the remaining liquid amount was calculated according to the following formula.
Liquid remaining amount (g) = 160 g of surface material after injection (W2) −mass of dried surface material (W1)
The composition of artificial urine is as follows. 1.94% by mass of urea, 0.7954% by mass of sodium chloride, 0.11058% by mass of magnesium sulfate (septahydrate), 0.06208% by mass of calcium chloride (dihydrate), 0.19788% by mass of potassium sulfate , Polyoxyethylene lauryl ether 0.0035 mass% and ion-exchanged water (remaining amount).

[Liquid flow distance on top sheet]
A diaper is fixed on a smooth surface of a table with an inclination angle of 45 ° with the top sheet side facing up and the ventral side facing down. Then, 40 g of physiological saline (0.9% saline using ion-exchanged water) colored with red No. 2 was injected into the disposable diaper at a position of 260 mm in the longitudinal direction from the abdominal end and in the center in the width direction. Inject using a pump at an infusion rate of 5 g / sec. Immediately after injection, the longest distance (mm) in which physiological saline has flowed on the top sheet is measured, and this is defined as the liquid flow distance.

[Liquid return amount]
The diaper was spread in a flat shape, an acrylic plate with a cylindrical injection portion was placed on the top sheet, a weight was placed on the acrylic plate, and a load of 2 kPa was applied to the absorber portion. The injection part provided in the acrylic plate has a cylindrical shape (height 53 mm) having an inner diameter of 36 mm. The acrylic plate has a cylindrical portion of 1/3 in the longitudinal direction and the central axis in the width direction. A through hole having an inner diameter of 36 mm is formed so that the central axes coincide with each other and communicates between the inside of the cylindrical injection portion and the surface sheet facing surface of the acrylic plate. The core wrap sheet covering the diaper's absorbent core is placed so that the central axis of the cylindrical injection portion of the acrylic plate comes to the position of 155 mm from the tip of the ventral portion in the longitudinal direction of the core wrap sheet, and 40 g of artificial urine is injected. Absorbed and allowed to stand for 10 minutes, and further injected 40 g of artificial urine for absorption. Such artificial urine injection operation was repeated four times, and a total of 160 g of artificial urine was absorbed in the diaper. After standing for 10 minutes from the completion of the injection, the above cylinder and pressure were removed. Next, filter paper No. manufactured by Advantech Co., Ltd., centering on the injection point of artificial urine in the diaper. A load was applied so that 16 pieces of 5C (100 mm × 100 mm, mass measurement W3) were applied, and a pressure of 3.5 kPa was further applied thereon. After the elapse of 2 minutes, the load was removed, the mass (W4) of the filter paper that absorbed artificial urine was measured, and the liquid return amount was calculated according to the following equation.
Liquid return amount (g) = mass of filter paper after pressurization (W4) −mass of first filter paper (W3)

[Liquid absorption]
The mass (W5) of the produced diaper is measured. Next, a diaper is fixed on a smooth surface of a table having an inclination angle of 20 ° with the top sheet side facing up and the abdomen side facing down. In this state, 40 g of artificial urine is injected and absorbed at a rate of 5 g / sec at a position 110 mm from the distal end of the longitudinal side of the core wrap sheet covering the absorbent core of the diaper using an infusion pump. The mixture was left for 5 minutes, and 40 g of artificial urine was further injected. Repeat the injection of artificial urine, stop the injection when it leaks from the lower end of the diaper, measure the mass (W6) of the diaper at that time, and calculate the amount of liquid absorption using the following formula did.
Liquid absorption (g) = Mass of diaper after absorption (W6)-Mass of diaper before absorption (W5)

As is clear from the results shown in Tables 2 to 5, the absorbent article using the nonwoven fabric of the present invention, particularly the air-through nonwoven fabric NW1, as a surface sheet is effectively prevented from flowing liquid along the surface. It can be seen that the liquid is difficult to remain. In particular, when the air-through nonwoven fabric of Example 17 is used as the top sheet, it can be seen that in addition to these effects, the liquid return amount is small and the liquid absorption amount is large.

As is apparent from the results shown in Table 6, the absorbent article using the nonwoven fabric of the present invention, in particular, the air-through nonwoven fabric NW2 as the surface sheet, is effectively prevented from flowing liquid along the surface, and the liquid remains on the surface. It turns out to be difficult. It can also be seen that the amount of liquid return is small.

The nonwoven fabric of the present invention is easily obtained by heat-treating a web or nonwoven fabric containing fibers whose hydrophilicity is lowered by heat, and the hydrophilicity of a desired portion is lowered.
The nonwoven fabric of the present invention has a part in which the hydrophilicity is partially reduced, and can be utilized for various applications by utilizing the characteristics.
According to the nonwoven fabric fiber treatment agent and the nonwoven fabric production method of the present invention, a nonwoven fabric having a portion with reduced hydrophilicity can be efficiently produced.
According to the method for controlling the hydrophilicity of the nonwoven fabric of the present invention, the part to be subjected to heat treatment can be prepared without mixing the fibers, making two layers, or performing the hydrophilic treatment in a separate process after making the nonwoven fabric. The hydrophilicity of the desired part of a nonwoven fabric can be reduced only by changing or controlling the passage of hot air.

According to the nonwoven fabric of the present invention, the liquid residue of the nonwoven fabric can be reduced by controlling the hydrophilicity of the nonwoven fabric. For example, when the nonwoven fabric of the present invention is used as a surface sheet of an absorbent article, the body fluid once absorbed may flow back to the surface side in contact with the skin of the wearer, or the body fluid may flow on the nonwoven fabric surface. Can be prevented. Therefore, when the nonwoven fabric of the present invention is used as, for example, a surface sheet of an absorbent article, the nonwoven fabric satisfies the absorption performance required for the surface sheet, such as reduction of the remaining liquid amount and reduction of the liquid flow amount.

According to the present invention, it is possible to effectively prevent the liquid from flowing along the surface and to obtain a nonwoven fabric in which the liquid hardly remains on the surface.

According to the present invention, it is possible to effectively prevent the liquid from flowing along the surface and to obtain a nonwoven fabric in which the liquid hardly remains on the surface. Moreover, a nonwoven fabric in which the liquid that has once permeated does not easily reverse is obtained.

Claims

A nonwoven fabric using heat-fusible fibers to which a fiber treatment agent is attached, wherein the fiber treatment agent comprises the following components (A), (B) and (C).
(A) polyorganosiloxane,
(B) an alkyl phosphate ester,
(C) Anionic surfactant represented by the following general formula (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 1 and R 2 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. , X represents —SO 3 M, —OSO 3 M or —COOM, and M represents H, Na, K, Mg, Ca or ammonium.)
The nonwoven fabric according to claim 1, wherein the polyorganosiloxane is contained in a proportion of 1% by mass to 30% by mass with respect to the total mass of the fiber treatment agent.
The nonwoven fabric according to claim 1 or 2, wherein the nonwoven fabric has a first surface of the nonwoven fabric and a second surface opposite to the first surface, and the hydrophilicity increases from the first surface side to the second surface side.
The nonwoven fabric according to any one of claims 1 to 3, wherein the heat-fusible fiber is a heat-extensible fiber whose length is extended by heat.
The nonwoven fabric according to any one of claims 1 to 4, wherein the nonwoven fabric has a concavo-convex shape, and the hydrophilicity increases from the top to the bottom of the convex portion.
The nonwoven fabric according to claim 5, wherein a difference between a contact angle of a top portion of the convex portion and a contact angle of the bottom portion is 2.5 degrees or more and 10 degrees or less.
It has a thin part formed by embossing and a thick part other than that, the thin part or its vicinity is hydrophilic, and the top part of the thick part is the thickness The nonwoven fabric of any one of Claims 1 thru | or 6 whose hydrophilicity is lower than the thin part or its vicinity part.
The nonwoven fabric is an air-through nonwoven fabric,
The heat-fusible fiber has a first layer and a second layer adjacent to the first layer, and the fiber treatment agent is attached to at least one of the first layer and the second layer.
The first layer is virtually divided into two in the thickness direction, and of the two parts divided into two, the part far from the second layer is the first layer first part, and the side close to the second layer When the first layer second part is compared with the first layer first part, the first layer second part, and the second layer, the following (11) and (12) The nonwoven fabric according to any one of claims 1 to 7, which satisfies the relationship.
(11) The first layer second portion has higher hydrophilicity than the first layer first portion.
(12) The hydrophilicity of any part of the second layer is higher than that of the second part of the first layer.
The nonwoven fabric according to claim 8, wherein the hydrophilicity of the second layer is the same in any part of the second layer.
The contact angle of water with respect to the fibers contained in the first part of the first layer is 70 degrees or more and 85 degrees or less, and the contact angle of water with respect to the fibers contained in the first part of the second part is 60 degrees or more and 80 degrees or less. Item 10. The nonwoven fabric according to item 8 or 9.
The nonwoven fabric according to any one of claims 8 to 10, wherein a contact angle of water with respect to fibers contained in the second layer is 20 degrees or more and 75 degrees or less.
The second layer is virtually divided into two in the thickness direction. Of the two parts divided in half, the part closer to the first layer is defined as the first part, and the part far from the first layer is defined as the first part. When the second part is the second part, the second layer first part, the second layer first part, and the second layer second part are compared with each other, the following relationships (13) and (14) are satisfied. The nonwoven fabric according to claim 8.
(13) The second layer first part has higher hydrophilicity than the first layer second part.
(14) The second layer second portion has a higher hydrophilicity than the second layer first portion.
The second layer is virtually divided into two in the thickness direction. Of the two parts divided in half, the part closer to the first layer is defined as the first part, and the part far from the first layer is defined as the first part. When it is set as the second part, the hydrophilicity of the first part first part, the first layer second part, the second layer first part, and the second layer second part is compared. The nonwoven fabric according to claim 8 satisfying the relationship of (16) and (17).
(15) The second layer first part has higher hydrophilicity than the first layer first part.
(16) The hydrophilicity of the first layer second portion is higher than that of the second layer first portion.
(17) The second layer second portion has higher hydrophilicity than the first layer second portion.
The nonwoven fabric according to any one of claims 8 to 13, wherein the first layer has a gradually increasing hydrophilicity from the first part toward the second part.
The nonwoven fabric according to any one of claims 8 to 14, wherein the heat-fusible fiber to which the fiber treatment agent is attached is contained in a first layer.
The nonwoven fabric is an air-through nonwoven fabric,
The heat-fusible fiber has a first layer and a second layer adjacent to the first layer, and the fiber treatment agent is attached to at least one of the first layer and the second layer.
The second layer is virtually divided into two in the thickness direction, and of the two divided parts, the part closer to the first layer is defined as the second layer first part, and the side far from the first layer When the second layer is the second part, the hydrophilicity of the first layer, the second layer first part, and the second layer second part is compared, and the following (21) and (22) The nonwoven fabric according to any one of claims 1 to 7, which satisfies the relationship.
(21) The hydrophilicity of the first part of the second layer is higher than that of the first layer.
(22) The second layer second portion has a higher hydrophilicity than the second layer first portion.
The nonwoven fabric according to any one of claims 12 to 16, wherein the second layer has a gradually increasing hydrophilicity from the first part toward the second part.
The nonwoven fabric according to any one of claims 12 to 17, wherein the heat-fusible fiber to which the fiber treatment agent is attached is contained in a second layer.
The convex part which protruded toward the 1st layer side from the 2nd layer side has two or more, In this convex part, the hydrophilicity becomes high from the top part to the bottom part of this convex part. The nonwoven fabric according to item 1.
The nonwoven fabric according to any one of claims 1 to 19, wherein a content ratio (the former: the latter) of the component (A) and the component (C) is 1: 3 to 4: 1 by mass ratio.
The nonwoven fabric according to any one of claims 1 to 20, wherein the component (C) is a dialkylsulfonic acid or a salt thereof.
The nonwoven fabric according to claim 21, wherein each of the two-chain alkyl groups of the dialkylsulfonic acid has 4 to 14 carbon atoms.
The nonwoven fabric according to any one of claims 1 to 122, wherein the polyorganosiloxane is polydimethylsiloxane.
The alkyl phosphate ester used as the component (B) is a completely neutralized or partially neutralized salt of a mono- or dialkyl phosphate ester having 16 to 18 carbon chains. Non-woven fabric.
An absorbent article using the nonwoven fabric according to any one of claims 1 to 24.
A fiber treatment agent for nonwoven fabric containing the following component (A), component (B) and component (C), wherein the content ratio of the component (A) to the component (C) (the former: the latter) is mass. The fiber treatment agent for nonwoven fabrics having a ratio of 1: 3 to 4: 1 and containing the component (A) in a proportion of 30% by mass or less with respect to the mass of the fiber treatment agent.
(A) polyorganosiloxane,
(B) an alkyl phosphate ester,
(C) Anionic surfactant represented by the following general formula (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 1 and R 2 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. , X represents —SO 3 M, —OSO 3 M or —COOM, and M represents H, Na, K, Mg, Ca or ammonium.)
The fiber treatment agent for nonwoven fabric according to claim 26, wherein the polyorganosiloxane is polydimethylsiloxane.
The polydimethylsiloxane is composed of two or more types of polydimethylsiloxane, one of which is composed of polydimethylsiloxane having a weight average molecular weight of 100,000 or more, and the other is composed of polydimethylsiloxane having a weight average molecular weight of less than 100,000. The fiber treatment agent for nonwoven fabrics according to claim 26 or 27.
The fiber treatment agent for nonwoven fabric according to any one of claims 26 to 28, wherein the component (C) is a dialkylsulfonic acid or a salt thereof.
A heat-fusible fiber to which the fiber treatment agent according to any one of claims 26 to 29 is adhered.
The heat-fusible fiber according to claim 30, wherein the heat-fusible fiber is a heat-extensible fiber.