Fiber treatment agent

Abstract

To provide a fiber treatment agent capable of imparting excellent liquid draw-in properties, liquid transferability, and low liquid retention to fibers.SOLUTION: The fiber treatment agent of the present invention comprises: (A) a compound represented by general formula (I), H-(PO)r-O-R; and (B) a cationic compound. [In general formula (I), PO is an oxypropylene group; r is the average number of moles of PO added, and is a number from 8 to 40; and R represents a linear or branched alkyl group having 6 to 24 carbon atoms. If n refers to the number of carbon atoms in R, then 0.3≤r / (n+r)≤0.8.]SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a fiber treating agent used for the purpose of modifying fibers. [Background technology]

[0002] The present applicant previously proposed an improved technology for liquid film cleaving agents in Patent Document 1. The liquid film cleaving agent described in Patent Document 1 is an agent that inhibits the formation of a liquid film between constituent fibers of a nonwoven fabric or on the surface of constituent fibers, and a nonwoven fabric containing this agent is less likely to leave liquid on the surface, i.e., has excellent dryness, and is suitable as a top sheet for absorbent articles such as sanitary napkins and disposable diapers. Patent Document 1 describes polyoxyalkylene alkyl ethers, polyoxyalkylene glycols, etc. as specific examples of the liquid film cleaving agent (e.g., claim 7 of the same document).

[0003] Patent Document 2 describes the application of a specific blood modifying agent with a low IOB value to the skin-facing surface of a topsheet in an absorbent article (the surface of the absorbent article facing the wearer's skin). The blood modifying agent has a mechanism for reducing the viscosity and surface tension of blood, and by applying it to the topsheet, excreted fluids such as menstrual blood are absorbed into the absorbent body without remaining on the topsheet. Patent Document 2 describes polyoxyalkylene glycol and the like as specific examples of the blood modifying agent (claims 10-11 of the same document).

[0004] Patent Document 3 describes a synthetic fiber treatment agent containing a compound having an alkyleneoxy group with 2 to 4 carbon atoms (Claim 1, etc.). The treatment agent described in Patent Document 3 is intended to facilitate processing steps such as spinning and drawing during the production of synthetic fibers, and it is said that applying the treatment agent to fibers can reduce friction between the fibers and metals or the like that come into contact with the fibers. Patent Document 3 does not describe absorbent articles. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2016-117981 A [Patent Document 2] Patent No. 5925015 [Patent Document 3] JP 2021-152238 A Summary of the Invention [Problem to be solved by the invention]

[0006] As a surface sheet for an absorbent article, a nonwoven fabric mainly made of hydrophobic synthetic fibers treated with a hydrophilic fiber treatment agent is known. In general, a surface sheet for an absorbent article is required to receive liquids such as menstrual blood and urine excreted by a wearer of the absorbent article on one side (skin-facing side), and then quickly draw the liquid into the inside of the surface sheet and transfer it to the outside from the other side (non-skin-facing side), without leaving any liquid inside the surface sheet. However, since the surface of hydrophobic synthetic fibers is inherently water-repellent, a nonwoven fabric mainly made of hydrophobic synthetic fibers does not exhibit liquid-attracting properties as it is and cannot be used as a surface sheet for an absorbent article. However, by attaching a hydrophilic fiber treatment agent to the surface of the hydrophobic synthetic fibers to make the surface hydrophilic, the nonwoven fabric exhibits liquid-attracting properties and can be used as a surface sheet.

[0007] Thus, the hydrophilicity of the fiber treatment agent is advantageous in terms of imparting liquid attraction to the nonwoven fabric as the topsheet to which it is applied, but on the other hand, it can be disadvantageous in terms of the above-mentioned property of transferring absorbed liquid to the outside of the sheet (liquid transferability) and property of not leaving absorbed liquid inside the sheet (low liquid residue). That is, if the fiber treatment agent attached to the constituent fibers of the topsheet is hydrophilic, liquid such as menstrual blood may dissolve with the fiber treatment agent and adhere to the constituent fibers via the fiber treatment agent. When liquid adheres to the fibers via the fiber treatment agent in this way, the liquid transferability decreases and liquid is likely to remain inside the sheet, which may lead to inconveniences such as a decrease in the dryness of the topsheet and the occurrence of liquid return. According to the findings of the present inventors, body fluids with relatively high viscosity, such as menstrual blood, are particularly likely to adhere to fibers via hydrophilic fiber treatment agents, which is likely to cause the above-mentioned inconveniences. No fiber treatment agent has yet been provided that can provide fibers that can exhibit excellent liquid attraction, liquid transferability, and low liquid residue even with high-viscosity aqueous liquids such as menstrual blood.

[0008] The present invention relates to providing a fiber treating agent which can impart excellent liquid attraction, liquid migration and low liquid residue to fibers. [Means for solving the problem]

[0009] The present invention is a fiber treatment agent containing component A represented by the following general formula (I). In one embodiment of the fiber treatment agent of the present invention, it is preferable to further contain a cationic compound as component B. H-(PO) r -OR (I) [In the general formula (I), PO is an oxypropylene group, r is the average number of moles of PO added and is a number of 8 to 40, and R is a linear or branched alkyl group having 6 to 24 carbon atoms. When the number of carbon atoms in R is n, 0.3≦r / (n+r)≦0.8.] Other features, advantages and embodiments of the present invention are described below. Effect of the Invention

[0010] According to the present invention, there is provided a fiber treating agent which can impart excellent liquid attraction, liquid migration and low liquid residue to fibers.

[0011] A nonwoven fabric to which the fiber treatment agent of the present invention has been applied exhibits excellent liquid attraction, liquid migration and low liquid residue even with highly viscous aqueous liquids such as menstrual blood. For example, when used as a top sheet of an absorbent article such as a sanitary napkin, liquid return is unlikely to occur and an excellent dry feel is achieved. The term "high viscosity" refers to a viscosity of 20 cP or more measured at a temperature of 20°C using a B-type viscometer (e.g., digital viscometer TVB-10R manufactured by Toki Sangyo Co., Ltd.) with rotor No. 12 as the rotor at a rotation speed of 12 rpm for a measurement time of 30 seconds. The term "liquid return" refers to the phenomenon in which liquid such as menstrual blood that has migrated from the skin-facing side of the top sheet of an absorbent article to the non-skin-facing side returns to the skin-facing side of the top sheet due to the body pressure of the wearer of the absorbent article, etc. [Brief description of the drawings]

[0012] [Figure 1] FIG. 1 is an explanatory diagram of a method for measuring the static contact angle of a fiber treatment agent. [Diagram 2] FIG. 2 is an explanatory diagram of a method for measuring the contact angle hysteresis of a fiber treatment agent. [Diagram 3] FIG. 3 is an explanatory diagram of a method for measuring the residual rate of a fiber treatment agent. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] The fiber treatment agent of the present invention contains components A and B as essential components, and can impart excellent liquid attraction, liquid migration, and low liquid residue to synthetic fibers that are inherently hydrophobic and widely used as constituent fibers of nonwoven fabrics. As described above, liquid attraction, liquid migration, and low liquid residue are in a trade-off relationship, and it was difficult to obtain synthetic fibers that meet these three performances at a high level with conventional hydrophilic fiber treatment agents, but the fiber treatment agent of the present invention overcomes this difficulty by adopting component A. On the other hand, component A has a problem that it has a weaker interaction with the surface of synthetic fibers and a slightly inferior fixation to the surface compared to lipophilic components that impart water repellency to the target of application, such as alkyl phosphate esters and polytetrafluoroethylene. Therefore, the fiber treatment agent of the present invention uses component B, which is a cationic compound that has a high affinity for both component A and the surface of synthetic fibers, thereby solving the problem of component A and enabling the desired effect of the present invention to be expressed.

[0014] Component A, which is one of the essential components of the fiber treatment agent of the present invention, is a compound represented by the following general formula (I). H-(PO) r -OR (I) [In the general formula (I), PO is an oxypropylene group, r is the average number of moles of PO added and is a number of 8 to 40, and R is a linear or branched alkyl group having 6 to 24 carbon atoms. When the number of carbon atoms in R is n, 0.3≦r / (n+r)≦0.8.]

[0015] As is clear from the general formula (I), component A is a polyoxypropylene ether modified alkyl compound, and is mainly composed of a polyoxypropylene group (hereinafter also referred to as a "POP group"). Since the POP group contains a polar ether part and a non-polar propylene part, component A containing a POP group exhibits intermediate properties between hydrophilicity and hydrophobicity. One of the reasons why the fiber treatment agent of the present invention can achieve high levels of liquid attraction, liquid migration, and low liquid residue in the fibers to which it is applied is because it contains component A having such moderate hydrophilicity and hydrophobicity. The effect of the fiber treatment agent of the present invention in imparting liquid attraction to fibers is mainly due to the fiber treatment agent having hydrophilicity. In addition, the effect of the fiber treatment agent of the present invention in imparting liquid migration and low liquid residue to fibers is mainly due to the fiber treatment agent having hydrophobicity.

[0016] In the general formula (I), PO may be either a straight chain or a branched chain, but is preferably a branched chain from the viewpoint of ensuring the desired effects of the present invention.

[0017] In the general formula (I), r is the average number of moles of PO added. In the present invention, the "average number of moles added" means the average value of the number of moles of PO added to 1 mole of the compound represented by the general formula (I). From the viewpoint of increasing the hydrophilicity of the fiber treatment agent and imparting excellent liquid attraction to the fiber to which the fiber treatment agent is applied, the average number of moles r of PO added is 8 or more, preferably 10 or more, and more preferably 12 or more. Also, from the viewpoint of providing appropriate hydrophilicity of the fiber treatment agent and imparting excellent liquid migration and low liquid residue to the fiber to which the fiber treatment agent is applied, the average number of moles r of PO added is 40 or less, preferably 32 or less, more preferably 24 or less, and even more preferably 20 or less.

[0018] In the general formula (I), R is a linear or branched alkyl group having 6 to 24 carbon atoms. Since Component A has such an alkyl group, it has wettability with respect to the surface of synthetic fibers and can adhere to the surface. From the viewpoint of imparting wettability to the synthetic fiber surface to the fiber treatment agent, the number of carbon atoms in R is 6 or more, preferably 10 or more, and more preferably 14 or more. In addition, the number of carbon atoms in R is 24 or less, preferably 22 or less, and more preferably 20 or less. Preferred specific examples of R include a decyl group, a lauryl group, a myristyl group, a cetyl group, a stearyl group, and a behenyl group.

[0019] In the general formula (I), the average number of moles of PO added r and the number of carbon atoms n of R (alkyl group) satisfy the relationship of 0.3≦r / (n+r)≦0.8, so that the balance between the hydrophilicity and hydrophobicity of component A is good enough to achieve high levels of liquid attraction, liquid migration, and low liquid residue in the fiber to which the fiber treatment agent of the present invention is applied. By setting r / (n+r) to 0.3 or more, component A can be prevented from becoming excessively hydrophobic, and by setting r / (n+r) to 0.8 or less, component A can be prevented from becoming excessively hydrophilic. In any case, by setting within the range, it is possible to achieve compatibility between liquid attraction, liquid migration, and low liquid residue in the fiber to which the fiber treatment agent of the present invention is applied. r / (n+r) is preferably 0.4 or more, and preferably 0.7 or less, more preferably 0.6 or less.

[0020] The water solubility of component A at 25°C is preferably less than 0.01g, more preferably 0.001g or less. That is, it is preferable to select a component A whose water solubility at 25°C is within the above range. In the present invention, the "water solubility at 25°C" refers to the soluble mass of the measurement object (component A) in 100g of ion-exchanged water at a water temperature of 25°C, and the smaller the water solubility value, the lower the solubility in water is evaluated to be. When the water solubility of component A at 25°C is less than 0.01g, the fiber treatment agent containing component A becomes less soluble in aqueous liquids such as menstrual blood and urine, and as a result, the liquid becomes less likely to adhere to the fiber surface to which the fiber treatment agent is applied, and the effect of imparting liquid migration and low liquid residual properties to the fiber can be further improved. In the present invention, the smaller the water solubility of component A, the more preferable, and the lower limit of the water solubility of component A is not particularly limited. The water solubility is measured by the following method.

[0021] <Method of measuring water solubility> In an environment with an atmospheric temperature of 25°C and a relative humidity (RH) of 65%, 100 g of ion-exchanged water is stirred with a stirrer while gradually dissolving the measurement object (for example, component A), and the degree of dissolution is visually observed. The amount of dissolution of the measurement object at the point when the measurement object no longer dissolves, that is, when any one of floating, precipitation, deposition, and cloudiness is visually confirmed, is taken as the water solubility. Specifically, the measurement object is added every 0.01 g and measured. As a result, if it is observed that even 0.01 g does not dissolve, it is considered to be "less than 0.01 g", and if it is observed that 0.01 g dissolves and 0.02 g does not dissolve, it is considered to be "0.01 g". Note that when the measurement object is a surfactant, "dissolution" means both monodisperse dissolution and micelle dispersion dissolution, and the amount of dissolution at the point when floating, precipitation, deposition, and cloudiness are observed is taken as the water solubility.

[0022] Component A preferably has a kinematic viscosity of 5 mm at 25°C. 2 / s or less, preferably 3 mm 2 / s or less, more preferably 1 mm 2 / s or less. The kinetic viscosity is calculated by multiplying the time (seconds) required for a certain volume of liquid to naturally flow down the capillary of a viscometer at a specified temperature (25°C in the present invention) by the constant of the viscometer, and the smaller the kinetic viscosity value, the higher the fluidity is evaluated to be. The kinetic viscosity is measured in accordance with JIS K2283. If the kinetic viscosity of component A at 25°C is 5mm 2 By setting the fiber treatment agent containing component A at a viscosity of 100 / s or less, the fiber treatment agent containing component A has high fluidity and is flexible, so that the agent moves easily when applied to the fiber surface, and the effect of imparting liquid migration and low liquid residue to the fiber can be further improved.

[0023] The mass average molecular weight of Component A is not particularly limited, but from the viewpoint of increasing the fluidity and flexibility of the fiber treatment agent containing Component A and more reliably achieving the desired effects of the present invention, it is preferably 50 or more, more preferably 500 or more, and preferably 10,000 or less, more preferably 5,000 or less, and even more preferably 2,000 or less. The mass average molecular weight of component A is measured using a gel permeation chromatograph (GPC) "CCPD" (product name, manufactured by Tosoh Corporation). The measurement conditions are as follows. The molecular weight is calculated using polystyrene. Separation column: GMHHR-H + GMHHR-H (cation) Eluent: L-Farmin DM20 / CHCl3 Solvent flow rate: 1.0ml / min Separation column temperature: 40℃

[0024] Specific examples of component A include POP lauryl ether, POP isolauryl ether, POP·POE lauryl ether, POP·POE isolauryl ether, POP myristyl ether, POP isomyristyl ether, POP·POE myristyl ether, POP·POE isomyristyl ether, POP cetyl ether, POP isocetyl ether, POP·POE cetyl ether, POP·POE isocetyl ether, POP stearyl ether, POP isostearyl ether, POP·POE stearyl ether, POP·POE isostearyl ether, and the like, and more specific examples include POP-5 lauryl ether, POP-5-POE-5-lauryl ether, POP-8-POE-1 cetyl ether, POP-15 stearyl ether, and the like. The fiber treating agent of the present invention may contain, as component A, one type of substance alone, or may contain two or more types of substances.

[0025] Component B, which is another essential component of the fiber treatment agent of the present invention, is a cationic compound. As described above, component A contained in the fiber treatment agent of the present invention shows intermediate properties between hydrophilicity and hydrophobicity, which allows the fiber to have both liquid attraction, liquid migration, and low liquid residue. However, due to the intermediate properties of component A with respect to water, the fixability of the fiber treatment agent to the fiber surface may be reduced, and the desired effect may not be fully achieved. More specifically, the synthetic fiber surface, which is a typical application target of the fiber treatment agent of the present invention, is easily negatively charged due to the influence of static electricity, etc., whereas the POP group of component A contained in the fiber treatment agent is easily polarized negatively by the electron donation of the alkyl group, so that the two are easily electrically repelled, and component A tends to be difficult to fix to the synthetic fiber surface. In contrast, in the fiber treatment agent of the present invention, component A is used in combination with component B, which is a cationic compound, to electrically charge the fiber treatment agent as a whole to be electrically neutral or positive, thereby improving the fixability to the synthetic fiber surface. The fiber treating agent of the present invention may contain, as component B, one type of cationic compound alone, or may contain two or more types of cationic compounds.

[0026] A cationic surfactant is a specific example of a cationic compound that can be used as component B. Since component A is water-insoluble, a surfactant is preferable as component B to be used in combination with component A from the viewpoint of improving the miscibility of the fiber treatment agent with polar components such as water. When the fiber treatment agent of the present invention is applied to a fiber aggregate such as a fiber or nonwoven fabric, the fiber treatment agent may be dissolved or dispersed in a polar component such as water, and if the fiber treatment agent has high miscibility with the polar component, the handleability of the fiber treatment agent can be improved. The mass average molecular weight of the cationic surfactant, Component B, is preferably 20 or more, more preferably 200 or more, and is preferably 999 or less, more preferably 500 or less, from the viewpoint of ensuring the effect of Component B as a surfactant.

[0027] Among cationic surfactants, component B is preferably a quaternary ammonium salt. Examples of quaternary ammonium salts include tetraalkylammonium salts, benzylalkylammonium salts, benzyltrialkylammonium salts, alkylbenzyldimethylammonium salts, mono-long-chain alkyltrimethylammonium salts, and di-long-chain alkyldimethylammonium salts. Specific examples of quaternary ammonium salts include cetyltrimethylammonium chloride, stearyltrimethylammonium chloride, behenyltrimethylammonium chloride, behenyldimethylhydroxyethylammonium chloride, distearyldiammonium chloride, stearyldimethylbenzylammonium chloride, distearyldimethylammonium chloride, dicetylmethylammonium chloride, cetyltriethylammonium methylsulfate, and benzalkonium chloride.

[0028] Other specific examples of cationic compounds that can be used as component B include polymers having cationic groups. This is because polymers have high dynamic viscosity, loss modulus or storage modulus in dynamic viscoelasticity due to intermolecular entanglement, physical crosslinking, etc., and are preferable from the viewpoint of localized stability. From the viewpoint of ensuring the effect of component B being a polymer, the mass average molecular weight of component B is preferably 1000 or more, more preferably 10000 or more, and preferably 500000 or less, more preferably 50000 or less. Component B, which is a polymer, has a larger mass average molecular weight than component B, which is a cationic surfactant. The mass average molecular weight of component B, which is a cationic surfactant or a polymer, can be measured in accordance with the method for measuring the mass average molecular weight of component A described above.

[0029] Specific examples of "polymers having cationic groups" that can be used as component B include polymers having quaternary ammonium bases. Examples of polymers having quaternary ammonium bases include diallyl dimethyl ammonium chloride polymers, diallyl methyl ethyl ammonium ethyl sulfate polymers, diallyl methyl ethyl ammonium ethyl sulfate-sulfur dioxide copolymers, diallyl dimethyl ammonium chloride-sulfur dioxide copolymers, and diallyl dimethyl ammonium chloride-acrylamide copolymers. As the polymer having a cationic group, commercially available products can be used, examples of which include PAS-H-5L (manufactured by Nittobo Medical Co., Ltd.); Unisense FPV1000L (manufactured by Senka Corporation); and MERQUAT 100 (manufactured by Lubrizol).

[0030] In the fiber treatment agent of the present invention, the ratio of the mass content of component B to the total mass content of components A and B (hereinafter also referred to as "component B occupancy") is preferably 25% by mass or less, more preferably 15% by mass or less, even more preferably 10% by mass or less, and even more preferably 5% by mass or less. The cationic compound, which is component B, typically has a polar group such as a quaternary ammonium salt, a quaternary phosphonium salt, an imidazolium group, or a pyridinium group, so that when the component B occupancy rate increases, the water solubility of the entire fiber treatment agent improves and the adhesion of body fluids (aqueous fluids) such as menstrual blood to the fiber treatment agent tends to improve, resulting in reduced liquid migration and low liquid residue in the fiber to which the fiber treatment agent is applied, which may lead to inconveniences such as reduced dryness of the fiber and the occurrence of liquid return. Considering these factors, it is preferable to set an upper limit on the component B occupancy rate as described above to ensure the balance between hydrophilicity and hydrophobicity of the fiber treatment agent. The lower limit of the occupancy rate of component B is preferably 1 mass % or more, and more preferably 3 mass % or more, from the viewpoint of ensuring that the effects of component B (such as the effect of improving the fixation of the fiber treatment agent to the fiber) are achieved.

[0031] In the fiber treatment agent of the present invention, the ratio of the mass content of component A to the total mass content of components A and B (hereinafter also referred to as "component A occupancy") is preferably 75 mass% or more, more preferably 85 mass% or more, even more preferably 90 mass% or more, and even more preferably 95 mass% or more, from the viewpoint of ensuring that the effect of component A (such as the effect of adjusting the balance between hydrophilicity and hydrophobicity of the fiber treatment agent) is exerted. The upper limit of the component A occupancy is preferably 99 mass% or less, more preferably 97 mass% or less, from the viewpoint of leaving room for the inclusion of other components such as component B in the fiber treatment agent.

[0032] The total content of components A and B in the fiber treatment agent of the present invention is, from the viewpoint of ensuring the effects of both components, preferably 10 mass % or more, and more preferably 30 mass % or more, relative to the total mass of the fiber treatment agent; it may be 100 mass %, i.e., the fiber treatment agent may be composed only of both components.

[0033] The fiber treatment agent of the present invention may further contain a surfactant selected from the group consisting of anionic surfactants, nonionic surfactants and amphoteric surfactants (hereinafter also referred to as "Component C") in addition to the above-mentioned Components A and B. By including the surfactant of Component C in the fiber treatment agent, effects such as prevention of static charging, rust prevention against corrosion of processing equipment due to the hydrophilic components contained in the fiber treatment agent, and expression of antiseptic properties that enable long-term storage can be achieved. The fiber treating agent of the present invention may contain, as component C, one type of surfactant alone, or may contain two or more types of surfactants. The content of component C in the fiber treatment agent of the present invention is preferably 1 mass % or more, more preferably 3 mass % or more, and preferably 30 mass % or less, more preferably 10 mass % or less, based on the total mass of the fiber treatment agent.

[0034] The surfactant contained in the fiber treatment agent as component C is not particularly limited, provided that it is different from components A and B. Examples of the anionic surfactant include alkyl ether phosphate esters, dialkyl phosphate esters, and alkyl phosphate esters. Examples of the nonionic surfactant include polyoxyethylene alkyl ether, polyoxyalkylene glycol, and polyoxyalkylene dimethyl silicone. Examples of the amphoteric surfactant include alkylaminoacetic acid betaine, alkylhydroxysulfobetaine, and alkylamine oxide.

[0035] A preferred example of component C is a phosphate ester-type anionic surfactant. Generally, blood and urine contain phospholipids, and phosphate ester-type anionic surfactants have a high affinity with these phospholipids, so when the fiber treatment agent contains the surfactant, the wettability (adhesion) to the fiber surface is improved, and the desired effects of the present invention can be more reliably achieved. The phosphate ester-type anionic surfactant is not particularly limited, and examples thereof include alkyl ether phosphate esters, dialkyl phosphate esters, and alkyl phosphate esters.

[0036] The fiber treatment agent of the present invention may contain other components in addition to the above-mentioned components A, B and C, to the extent that the manifestation of the desired effects of the present invention is not inhibited. As the other components, the components contained in this type of fiber treatment agent can be used appropriately, and examples thereof include emulsifiers, stabilizers, antistatic agents (rust inhibitors), preservatives, antifungal agents and pH adjusters, and these can be used alone or in combination of two or more.

[0037] The fiber treatment agent of the present invention has a static contact angle of preferably 60 degrees or less, more preferably 45 degrees or less. The static contact angle is an index of the hydrophilicity of the fiber treatment agent, and the smaller the static contact angle, the more hydrophilic the fiber treatment agent is evaluated to be. The static contact angle is a value in the range of 0 to 180 degrees, and academically, when the static contact angle is 60 degrees or less, the object to be measured is hydrophilic, and when the static contact angle is more than 60 degrees, the object to be measured is hydrophobic. Since the fiber treatment agent having a static contact angle of 60 degrees or less is hydrophilic, it has high affinity with aqueous liquids such as menstrual blood and urine, and can more reliably impart excellent liquid attraction to the fiber. The lower limit of the static contact angle of the fiber treatment agent of the present invention is not particularly limited, and from the viewpoint of improving the liquid attraction of the fiber, the smaller the static contact angle, the more preferable, but from the viewpoint of suppressing the endless wetting and spreading of the aqueous liquid and realizing a good wearing feeling, it is preferably 5 degrees or more, more preferably 10 degrees or more. The static contact angle of the fiber treatment agent can be adjusted, for example, by appropriately adjusting the type and content in the fiber treatment agent of component A, and the type and content in the fiber treatment agent of component B. The static contact angle is measured by the following method.

[0038] The fiber treatment agent of the present invention preferably has a contact angle hysteresis (hereinafter, simply referred to as "contact angle hysteresis") of 0.2 or less, more preferably 0.1 or less, in dynamic contact angle measurement by sliding method. The contact angle hysteresis is calculated by placing a droplet of horse blood on the horizontal surface of a solid sample (a coating of the fiber treatment agent), tilting the solid sample to make the surface an inclined plane, causing the droplet to slide down the inclined plane from above to below, measuring the advancing contact angle θa and the receding contact angle θr of the droplet during the slide, and calculating the difference between the two contact angles (cosθr-cosθa). The contact angle hysteresis is an index of the synovial properties (slipperiness) of the fiber treatment agent, and the smaller the contact angle hysteresis value, the easier it is to evaluate that aqueous liquids such as menstrual blood and urine slide on the fiber treatment agent. The contact angle hysteresis is a value in the range of 0 to 2. Academically, when the surface of the solid sample on which the droplet is placed is a highly hydrophobic or water-repellent surface called super water-repellent or super oil-repellent, the contact angle hysteresis is about 0.2 (corresponding to about 10° as the difference between the forward contact angle θa and the backward contact angle θr). A fiber treatment agent having a contact angle hysteresis of 0.2 or less is less likely to adhere to aqueous liquids such as menstrual blood and urine, and can more reliably impart excellent liquid transferability to the fiber. The lower limit of the contact angle hysteresis of the fiber treatment agent of the present invention is not particularly limited, and from the viewpoint of improving the liquid transferability of the fiber, the smaller the contact angle hysteresis, the more preferable it is. However, from the viewpoint of imparting to the aqueous liquid an adhesiveness such that the aqueous liquid does not wet back from the fiber toward the wearer, the lower limit is preferably 0.01 or more, more preferably 0.05 or more. The contact angle hysteresis of the fiber treatment agent can be adjusted, for example, by appropriately adjusting the type and content of component A in the fiber treatment agent, and the type and content of component B in the fiber treatment agent. The contact angle hysteresis is measured by the following method.

[0039] The fiber treatment agent of the present invention has a residual rate (hereinafter, simply referred to as "residual rate") in dynamic contact angle measurement by sliding method of preferably 10.0% or less, more preferably 5.0% or less. The residual rate is calculated by placing a droplet of horse blood on the horizontal surface of a solid sample (a coating of the fiber treatment agent) and tilting the solid sample to make the surface an inclined surface, and allowing the droplet to slide down the inclined surface from the top to the bottom, and then calculating the ratio of the length of the droplet's adhesion part along the inclined surface to the total length of the droplet's sliding section along the inclined surface. The residual rate is an index of the low liquid residual property (difficulty of liquid remaining) of the fiber treatment agent, and the smaller the residual rate, the less likely aqueous liquid such as menstrual blood or urine will remain on the fiber treatment agent. A fiber treatment agent with a residual rate of 10.0% or less is less likely to allow aqueous liquid such as menstrual blood or urine to adhere and remain, and can more reliably impart excellent low liquid residual property to fibers. The lower limit of the residual rate of the fiber treatment agent of the present invention is not particularly limited, and from the viewpoint of improving the low liquid residual property of the fiber treatment agent, the lower the residual rate is, the more preferable, and ideally 0%, but from the viewpoint of imparting adhesiveness to the aqueous liquid such that the aqueous liquid does not wet back from the fiber toward the wearer, the residual rate is preferably 1% or more, more preferably 2% or more. The residual rate of the fiber treatment agent can be adjusted, for example, by appropriately adjusting the type and content of component A in the fiber treatment agent, and the type and content of component B in the fiber treatment agent. The residual rate is measured by the following method.

[0040] The fiber treatment agent of the present invention preferably has a sliding angle (hereinafter, simply referred to as "sliding angle") of 20 degrees or less, more preferably 10 degrees or less, in dynamic contact angle measurement by the sliding method. The sliding angle is measured by tilting a solid sample (a coating of the fiber treatment agent) at a constant speed with a droplet of horse blood placed on the horizontal surface of the solid sample, and measuring the inclination angle of the surface of the solid sample at the moment the droplet slides off. The sliding angle is an index of the synovial properties (slipperiness) of the fiber treatment agent, and the smaller the sliding angle, the easier it is for aqueous liquids such as menstrual blood and urine to slide on the fiber treatment agent. A fiber treatment agent with a sliding angle of 20 degrees or less is less likely to have aqueous liquids such as menstrual blood and urine adhere to it, and can more reliably impart excellent liquid migration properties to fibers. The lower limit of the sliding angle of the fiber treatment agent of the present invention is not particularly limited, and from the viewpoint of improving the synovial properties of the fiber treatment agent, the smaller the sliding angle, the better, but from the viewpoint of imparting to the aqueous liquid an adhesiveness sufficient to prevent the aqueous liquid from wetting back from the fiber toward the wearer, the sliding angle is preferably 1 degree or more, more preferably 3 degrees or more. The sliding angle of the fiber treatment agent can be adjusted, for example, by appropriately adjusting the type and content of component A in the fiber treatment agent, and the type and content of component B in the fiber treatment agent. The sliding angle is measured by the following method.

[0041] The static contact angle, contact angle hysteresis, residual rate, and sliding angle are measured using a solid sample prepared by the following method. First, the fiber treatment agent to be measured is dissolved or dispersed in ethanol or isopropanol to prepare a sample solution with a concentration of the fiber treatment agent of 10% by mass. Next, 1 mL of the sample solution is dropped onto the center of one side of a flat substrate (50 mm long, 50 mm wide, 1 mm thick) made of high-density polyethylene with a smooth surface, and the dropped sample solution is applied to one side of the substrate using a spin coater at a rotation speed of 1500 rpm for a rotation time of 5 seconds, and then the substrate is dried by heat treatment at 60°C for 30 minutes. In this way, a solid sample is obtained in which a coating of the fiber treatment agent is formed over the entire area of ​​one side of the substrate. The amount of fiber treatment agent applied to the solid sample can be calculated from the difference between the weight of the solid sample and the weight of the substrate before the sample solution is dropped.

[0042] 1 to 3 are schematic diagrams showing how various physical properties related to the fiber treatment agent, such as the static contact angle, are measured. In these figures, reference numeral 1 denotes a solid sample, reference numeral 2 denotes a coating of the fiber treatment agent (object to be measured), and reference numeral 3 denotes a substrate. Measurement of various physical properties, such as the static contact angle, is carried out in an environment with an ambient temperature of 20° C. and a relative humidity of 65%, in accordance with steps 1 to 3 below.

[0043] Step 1. Measuring the static contact angle Referring to FIG. 1, the solid sample 1 is placed so that the coating 2 is on top and horizontal (the inclination angle θ in FIG. 2 is 0 degrees), and 20 μL of horse blood is dropped onto the coating 2 to form a droplet 4 on the coating 2. As the horse blood, defibrinated horse blood manufactured by Japan Bio Test Laboratory Co., Ltd. can be used. The horse blood is intended to be menstrual blood (high-viscosity aqueous liquid), which is the main object of absorption by sanitary napkins, and is adjusted to have a viscosity of 24 cp at a liquid temperature of 20° C. The viscosity is measured using a B-type viscometer (for example, digital viscometer TVB-10R manufactured by Toki Sangyo Co., Ltd.) with rotor No. 12 as the rotor at a rotation speed of 12 rpm. Using a contact angle meter (for example, “DSA25T” manufactured by Cruz Co., Ltd.), the left and right contact angles θs of the droplet 4 in a side view as shown in FIG. 1 are measured, and the average value of the two measured values ​​is taken as the static contact angle of the object to be measured, i.e., the fiber treatment agent forming the coating 2.

[0044] Step 2. Measurement of sliding angle and contact angle hysteresis The contact angle hysteresis is measured immediately after the above-mentioned step 1. After the contact angle θs of the droplet 4 is measured in step 1, the fixed sample 1 is tilted to form a slope consisting of the coating 2, as shown in FIG. 2. The tilt operation of the fixed sample 1 is adjusted so that the tilt angle (angle between the fixed sample 1 and the horizontal plane) θ increases at a constant rate of 60 degrees / min, and is continued until the droplet 4 slides off. The maximum tilt angle θ is 90 degrees. During the tilting process of the fixed sample 1, the droplet 4 on the coating 2 is observed, and the tilt angle θ at the moment when the droplet 4 slides off is taken as the slide angle of the object to be measured, i.e., the fiber treatment agent forming the coating 2. The tilt operation of the fixed sample 1 is stopped at the point when the droplet 4 slides off. In addition, using a contact angle meter (for example, the DSA25T manufactured by Cruz), the advancing contact angle θa and the receding contact angle θr of the droplet 4 sliding down are measured, and the contact angle hysteresis of the object to be measured, i.e., the fiber treatment agent forming the coating 2, is calculated using the following formula. Contact angle hysteresis = cosθr-cosθa

[0045] Step 3. Measurement of residual rate The measurement of the residual ratio is carried out immediately after carrying out the above-mentioned step 2. After carrying out the step 2, as shown in Fig. 3, in a state where the droplet 4 remains on the inclined coating 2 (a state where the droplet 4 has finished sliding down), the sliding distance Ls of the droplet 4 and the length Lad of the portion of the coating 2 where the droplet 4 exists in the sliding direction (the direction indicated by the arrow in Fig. 2) are measured, and the ratio (%) of Ls to Lad is calculated, and this ratio is regarded as the residual ratio of the fiber treatment agent forming the measurement object, i.e., the coating 2. The sliding distance Ls is the distance Pm-Ea0 along the inclination direction of the coating 2 between the forward end Ea0 of the droplet 4 (the droplet 4 indicated by the dotted line in Fig. 3) immediately before sliding down and the maximum thickness part Pm of the droplet 4 in a state where it has stopped on the coating 2 after sliding down, The length Lad is the length Er-Pm along the inclination direction of the coating 2 between the rearward end Er of the droplet 4 that has slid down and stopped on the coating 2 and the maximum thickness part Pm. In addition, when the droplet 4 splits during the sliding process and multiple split droplets are generated on the coating 2, the maximum thickness part Pm used in calculating the sliding distance Ls of the droplet 4 is the maximum thickness part of the one (lowest split droplet) located at the bottom among the multiple split droplets. In addition, in a similar case, the length Lad of the droplet 4 in the sliding direction is the sum of the lengths Lad of the multiple split droplets that are different from each other in the sliding direction. For example, when the droplet 4 splits during the sliding process and two split droplets that are different from each other in the sliding direction are generated on the coating 2, the length Lad of each of the two split droplets in the sliding direction is measured by the above-mentioned procedure, and the sum of the two measured values ​​is regarded as the length Lad of the droplet 4 in the sliding direction.

[0046] The fiber treatment agent of the present invention can be prepared by mixing the above-mentioned components (component A, component B, component C, etc.). The fiber treatment agent of the present invention is typically liquid and has fluidity at room temperature and normal pressure. The term "room temperature and normal pressure" used here refers to an environment with an atmospheric temperature of 25°C and 1 atmospheric pressure.

[0047] The fiber treatment agent of the present invention is typically used by adhering to the surface of the fiber. For example, when the fiber treatment agent of the present invention is applied to a nonwoven fabric, which is a fiber assembly, the fiber treatment agent may be incorporated into the nonwoven fabric to which the fiber treatment agent has not been applied, or the fiber to which the fiber treatment agent has not been applied may be treated (pretreated) to contain the fiber treatment agent to obtain a pretreated fiber, and the pretreated fiber may be used to manufacture a nonwoven fabric according to a conventional method. The manufacture of a nonwoven fabric using the pretreated fiber typically proceeds in the order of the manufacture of a fiber web and the formation of a nonwoven fabric from the fiber web. The manufacture of the fiber web can be carried out by adopting a conventionally known method for manufacturing a fiber web, such as a card method, an airlaid method, or a spunbond method. The formation of a nonwoven fabric from the fiber web can be carried out by adopting a conventionally known method for forming a nonwoven fabric, such as a spunlace method, a needle punch method, a chemical bond method, or a dot-shaped embossing method.

[0048] The method of applying the fiber treatment agent of the present invention to a fiber or nonwoven fabric is not particularly limited, and includes, for example, a method of immersing the fiber or nonwoven fabric in a treatment liquid containing the fiber treatment agent. Another method includes a method of applying the fiber treatment agent or a treatment liquid containing the same to the fiber or nonwoven fabric. As the latter application method, a conventionally known application method can be adopted without particular limitation, and includes, for example, application by spray, application by slot coater, application by roll transfer such as gravure method, flexo method, and gate roll method, and application by dipping method.

[0049] The treatment liquid may be a mixture of a fiber treatment agent and a liquid medium. The liquid medium is preferably one that can adequately dissolve or disperse the fiber treatment agent to emulsify it. Examples of liquid media (i.e., solvents) that can dissolve the fiber treatment agent include organic solvents such as ethanol, methanol, isopropanol, acetone, and hexane. When the fiber treatment agent of the present invention contains a component other than component A and component B (e.g., a surfactant of component C), the treatment liquid may contain the other component.

[0050] When the fiber treatment agent of the present invention is applied to a fiber assembly such as a nonwoven fabric, the amount of the fiber treatment agent attached may be appropriately adjusted according to the use of the fiber assembly, and is not particularly limited. For example, when the fiber treatment agent of the present invention is applied to a nonwoven fabric used as a top sheet of an absorbent article, the content of the fiber treatment agent in the nonwoven fabric can be adjusted to be preferably 0.1 mass% or more, more preferably 0.2 mass% or more, and preferably 5.0 mass% or less, more preferably 2.0 mass% or less, based on the total mass of the nonwoven fabric. The above-mentioned "content of the fiber treatment agent in the nonwoven fabric" is calculated as the ratio of the mass of the fiber treatment agent to the total mass of the nonwoven fabric to be measured (the mass of the entire nonwoven fabric including the attachment of the fiber treatment agent, etc.).

[0051] Since the fiber treatment agent of the present invention provides hydrophilicity to the target, the target fiber is preferably one having poor hydrophilicity on the fiber surface, such as hydrophobic synthetic fibers, and a specific example of such fibers is thermoplastic fibers. Thermoplastic fibers are fibers containing thermoplastic resins. Examples of thermoplastic resins contained in thermoplastic fibers include polyolefins such as polyethylene and polypropylene; polyesters such as polyethylene terephthalate; polyamides such as nylon 6 and nylon 66; poly(meth)acrylic acid alkyl esters, polyvinyl chloride, and polyvinylidene chloride. The synthetic fibers to which the fiber treatment agent of the present invention is applied may be composite fibers such as core-sheath or side-by-side types, split fibers, modified cross-section fibers, heat-shrinkable fibers, etc. Composite fibers may be composed of a plurality of resin components.

[0052] The fiber aggregate such as a nonwoven fabric to which the fiber treatment agent of the present invention is applied is suitable as a component of an absorbent article. The term "absorbent article" as used herein includes articles used to absorb excrement (menstrual blood, urine, loose stool, sweat, etc.), such as disposable diapers, sanitary napkins, sanitary shorts, and incontinence pads. A fiber assembly such as a nonwoven fabric to which the fiber treatment agent of the present invention is applied is particularly useful as a member in an absorbent article that is arranged closer to the wearer's skin than the absorbent body. Examples of such members include a top sheet and a second sheet. The top sheet is a member that is arranged in a position where it can come into contact with the wearer's skin of the absorbent article. The second sheet is a member that is arranged between the top sheet and the absorbent body.

[0053] The nonwoven fabric to which the fiber treatment agent of the present invention is applied (hereinafter also referred to as "fiber-treated nonwoven fabric") may have a single layer structure or a laminate structure in which two or more layers are laminated in the thickness direction. The fiber-treated nonwoven fabric may be a so-called uneven nonwoven fabric in which a plurality of convex portions and concave portions located between the convex portions are formed on at least one side. When the fiber-treated nonwoven fabric is an uneven nonwoven fabric, the uneven nonwoven fabric is usually arranged in an absorbent article so that the uneven surface of the uneven nonwoven fabric faces the skin. Regardless of the form of the fiber-treated nonwoven fabric (layer structure, the presence or absence of unevenness, etc.), it is preferable for a fiber treatment agent to be present at least on the skin-facing surface, from the viewpoint of ensuring that the effects of the nonwoven fabric (the effect of exhibiting excellent liquid attraction, liquid transfer, and low liquid residue even with highly viscous aqueous liquids such as menstrual blood) are achieved.

[0054] A preferred embodiment of the fiber-treated nonwoven fabric includes an air-through nonwoven fabric or a spunbond nonwoven fabric. The "air-through nonwoven fabric" refers to a nonwoven fabric manufactured through a process (air-through processing process) in which a fluid (e.g., gas or steam) at 50°C or higher is sprayed onto a fiber web or nonwoven fabric. The "spunbond nonwoven fabric" refers to a laminated nonwoven fabric manufactured by a spunbond method. Since these nonwoven fabrics have excellent texture, fiber-treated nonwoven fabrics including these nonwoven fabrics, combined with the high level of dryness provided by the fiber treatment agent, can further improve the wearing comfort of absorbent articles. The fiber-treated nonwoven fabric may be composed of only an air-through nonwoven fabric or a spunbond nonwoven fabric, may include both nonwoven fabrics, or may include one or both of the two nonwoven fabrics and another nonwoven fabric.

[0055] One embodiment of the fiber-treated nonwoven fabric is a concave-convex nonwoven fabric containing thermoplastic fibers as constituent fibers. Specific examples of the concave-convex nonwoven fabric include nonwoven fabric 10 (see FIG. 3 in Patent Document 1), nonwoven fabric 20 (see FIG. 4 in Patent Document 1), nonwoven fabric 30 (see FIG. 5 in Patent Document 1), nonwoven fabric 40 (see FIG. 6 and FIG. 7 in Patent Document 1), nonwoven fabric 50 (see FIG. 8 and FIG. 9 in Patent Document 1), nonwoven fabric 60 (see FIG. 10 in Patent Document 1), and nonwoven fabric 70 (see FIG. 11 in Patent Document 1). The fiber-treated nonwoven fabric may have the same configuration as any one of the nonwoven fabrics 10 to 70, except for the fiber treatment agent.

[0056] The basis weight of the fiber-treated nonwoven fabric is not particularly limited, but as a component of an absorbent article, it is preferably 10 g / m 2 More than 100g / m 2 Less than 15g / m 2 More than 80g / m 2 The following is the result.

[0057] While the present invention has been described above based on its preferred embodiments, the present invention is not limited to the above-described embodiments and can be modified as appropriate without departing from the spirit of the present invention. The following supplementary notes are further disclosed regarding the above-described embodiment of the present invention. EXAMPLES

[0058] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to such examples.

[0059] [Examples 1 to 3, Comparative Examples 1 to 4] The fiber treatment agent was prepared by mixing components 1 and 2 shown in Table 1 below, and then a liquid medium was further mixed to prepare a treatment liquid that is liquid at room temperature and normal pressure. Isopropanol was used as the liquid medium in an amount of 90 mass % relative to the entire treatment liquid. Details of components 1 and 2 are as follows.

[0060] (Component 1) Component 1-1: PPG-15 stearyl ("MS-70K" manufactured by NOF Corporation). Component 1-1 is a type of the above-mentioned Component A. In Component 1-1, in the above-mentioned general formula (I), the average number of moles of PO added r is 15, R is a "linear alkyl group having 18 carbon atoms", and when the number of carbon atoms of R is n, "r / (n+r)" (in Table 1 below, indicated as "PO / (C+PO)") is 0.45. Component 1-1 has a water solubility of less than 0.01 g and a kinetic viscosity at 25°C of 0.9 mm 2 / s, and the mass average molecular weight is 1140 (all values ​​are measured by the above-mentioned method. The same applies below). Component 1-2: PPG-40 butyl ("MS-370" manufactured by NOF Corporation). Component 1-2 is not Component A. Component 1-2 is a polymer having an average added mole number r of PO of 40 in the general formula (I), R is a "linear alkyl group having 4 carbon atoms", and when the number of carbon atoms of R is n, "r / (n+r)" is 0.91. Component 1-2 has a water solubility of less than 0.01 g and a kinetic viscosity at 25°C of 7 mm 2 / s, and the mass average molecular weight is 2378. Component 1-3: Polydimethylsiloxane ("KF-96-100cs" manufactured by Shin-Etsu Chemical Co., Ltd.). Component 1-3 is not the above-mentioned Component A. Component 1-3 has a water solubility of less than 0.01 g and a kinetic viscosity of 1 mm at 25°C. 2 / s, and the mass average molecular weight is 8000. Component 1-4: PPG-38 steareth-6 ("SP2010" manufactured by Kao Corporation). Component 1-4 is not Component A. Component 1-4 has, in the general formula (I), an average number of moles of PO added, r, of 38, an average number of moles of oxyethylene groups (hereinafter also referred to as "EO") added, of 6, R is a "linear alkyl group having 18 carbon atoms", and when the number of carbon atoms of R is n, "r / (n+r)" is 2.44. Component 1-4 has a water solubility of more than 0.01 g, a kinetic viscosity at 25°C of 6 mm 2 / s, and the mass average molecular weight is 2722. In this specification, the term "average number of moles added" refers to the average value of the number of moles of functional groups (oxyalkylene groups) such as PO and EO added to 1 mole of a monomer.

[0061] (Component 2) Component 2-1: Diallyldimethylammonium chloride polymer ("PAS-H-5L" manufactured by Nittobo Medical Co., Ltd.) Component 2-1 is a polymer having a cationic group and has a mass average molecular weight of 30,000. Component 2-2: Aqueous solution of dimethylaminoethyl methacrylate-methyl sulfate copolymer (Unisense FPV1000L, manufactured by Senka Corporation). Component 2-2 is a polymer having a cationic group and has a mass average molecular weight of 300,000.

[0062] [Manufacturing example: Manufacturing of nonwoven fabric] A nonwoven fabric was produced containing any one of the treatment liquids containing the fiber treatment agents of each Example and Comparative Example. Specifically, the fibers that are the raw material of the nonwoven fabric were pretreated with the treatment liquid to obtain pretreated fibers, and the pretreated fibers were used to produce a nonwoven fabric according to a conventional method. The pretreatment was a process in which the fibers were immersed in the treatment liquid, and then the fibers were dried to completely volatilize the liquid medium. The nonwoven fabric produced was a concave-convex nonwoven fabric similar to the nonwoven fabric 10 described in Patent Document 1 (see FIG. 3 of the document), and was produced according to the contents of

[0032] to

[0048] of JP 2002-187228 A. The concave-convex nonwoven fabric had a laminated structure of a first layer containing non-heat-shrinkable fibers and a second layer in which the heat-shrinkable fibers had exhibited heat shrinkage, and these two layers were joined via a joint formed by embossing (squeezing) from the first layer side toward the second layer side, and the surface of the first layer (the surface opposite to the surface facing the second layer) was a concave-convex surface having a plurality of recesses corresponding to the joint and a plurality of protrusions that were not formed in the joint. The basis weight of the first layer was 30 g / m 2 The second layer has a basis weight of 40 g / m 2 The fibers constituting the first layer were core-sheath type composite fibers (fiber diameter 18 μm, hydrophobic synthetic fibers) with a polyethylene terephthalate fiber as the core and a high-density polyethylene fiber as the sheath. The fibers constituting the second layer were core-sheath type composite fibers (fiber diameter 18 μm, hydrophobic synthetic fibers) with a polypropylene fiber as the core and a linear low-density polyethylene fiber as the sheath. The pretreatment was applied only to the fibers constituting the first layer, and not to the fibers constituting the second layer. The content of the fiber treatment agent in the produced nonwoven fabric was 0.5% by mass with respect to the total mass of the nonwoven fabric.

[0063] [Evaluation test] The amount of wet-back of the nonwoven fabrics produced using the fiber treatment agents of each of the Examples and Comparative Examples was evaluated by the following method. The results are shown in Table 1 below.

[0064] <Method for evaluating the amount of liquid return> The nonwoven fabric to be evaluated is placed horizontally so that the surface (the surface on the side of the first layer) that will be the skin-facing surface when incorporated into an absorbent article is the upper surface, and an elliptical injection port (long diameter 50 mm, short diameter 23 mm) is placed on the nonwoven fabric. 6 g of horse blood (defibrous horse blood, manufactured by Japan Bio Test Laboratory Co., Ltd.) with a viscosity of 24 cP at a liquid temperature of 20°C is measured in a 10 cc injection beaker. The viscosity of the horse blood is a value measured using a B-type viscometer (for example, digital viscometer TVB-10R manufactured by Toki Sangyo Co., Ltd.) with rotor No. 12 as the rotor and a rotation speed of 12 rpm. The horse blood measured in the injection beaker is poured into the injection port at once, and then left for 1 minute. Immediately after that, 16 wipes ("Kleenex" manufactured by Nippon Paper Crecia Co., Ltd.) and a weight are placed in order on the injection site of the nonwoven fabric and left to stand for 5 seconds. During this rest period, 5 g / m 2 The pressure is 5g / m 2 is an estimation of the pressure (wearer's body pressure) exerted on the sanitary napkin when it is worn. The weight is then removed, and the mass (post-mass) of the wipe material is measured. The amount of liquid return is determined as the mass (mg) of horse blood absorbed by the wipe material, obtained by subtracting the measured mass (initial mass) of the wipe material, which was measured before the liquid was poured, from the measured post-mass. The above series of operations is carried out three times for each type of nonwoven fabric to be evaluated, and the average of the three amounts of liquid return is determined as the amount of liquid return for that nonwoven fabric. The smaller the value of the amount of liquid return, the less likely that the nonwoven fabric will experience liquid return, and the higher the evaluation of the fiber treatment applied to that nonwoven fabric.

[0065] [Table 1]

[0066] As shown in Table 1, the fiber treatment agents of the Examples contain, as component 1 functioning as a hydrophilizing agent, a compound represented by the general formula (I) above and satisfying the condition "0.3≦PO / (C+PO)≦0.8", i.e., component A, and also contain component 2 (component B) consisting of a cationic compound, and therefore the amount of liquid wetting was less than that of the fiber treatment agents of the Comparative Examples which do not satisfy these conditions. From this, it can be seen that in order to obtain a fiber treatment agent which is less likely to cause liquid wetting and can produce a nonwoven fabric useful as a topsheet for absorbent articles, i.e., a fiber treatment agent which can impart excellent liquid attraction, liquid migration, and low liquid residue to fibers, it is effective to use component A as a component functioning as a hydrophilizing agent in the fiber treatment agent and component B consisting of a cationic compound. In addition, the "PO / (C+PO)" (= "r / (n+r)") in each example in Table 1 is 0.45. However, when BIOVIA COSMOTHERM (Dassault Systèmes) was used to calculate the physical properties related to the determination of the amount of liquid return (e.g., static contact angle, surface charge distribution with respect to water (i.e., water affinity), etc.) when the PO / (C+PO) value is other values, it was confirmed that when the PO / (C+PO) value is 0.3 or more and 0.8 or less, good results similar to those of each example in Table 1 can be obtained. [Explanation of symbols]

[0067] 1. Solid sample 2 Coating of the object to be measured (textile treatment agent) 3. Substrate 4 droplets

Claims

1. A fiber treatment agent comprising, as component A, a compound represented by the following general formula (I), and as component B, a cationic compound: H-(PO) ｒ -O-R (I) [In the general formula (I), PO is an oxypropylene group, r is the average number of moles of PO added and is a number from 8 to 40, and R is a linear or branched alkyl group having 6 to 24 carbon atoms. When the number of carbon atoms in R is n, 0.3≦r / (n+r)≦0.8.]

2. 2. The fiber treatment agent according to claim 1, wherein the ratio of the mass of the component B to the total mass of the components A and B is 25 mass % or less.

3. 3. The fiber treatment agent according to claim 1, wherein the component B is a polymer having a cationic group.

4. The fiber treating agent according to any one of claims 1 to 3, which has a static contact angle of 60 degrees or less.

5. The fiber treating agent according to any one of claims 1 to 4, which has a contact angle hysteresis of 0.2 or less in dynamic contact angle measurement by a sliding method.

6. The fiber treatment agent according to any one of claims 1 to 5, which has a residual rate of 10.0% or less in dynamic contact angle measurement by a sliding drop method.

7. The fiber treating agent according to any one of claims 1 to 6, which has a sliding angle of 20 degrees or less in dynamic contact angle measurement by a sliding method.

8. The fiber treatment agent according to any one of claims 1 to 7, wherein the water solubility of said component A at 25°C is less than 0.01 g.

9. The kinetic viscosity of the component A at 25°C is 5 mm ２ The fiber treatment agent according to any one of claims 1 to 8, wherein the molecular weight of the fiber is 1 / s or less.

10. The fiber treatment agent according to any one of claims 1 to 9, which contains a surfactant selected from the group consisting of anionic surfactants, nonionic surfactants and amphoteric surfactants.

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