Synthetic fibers, fiber treatments, and their uses.

Abstract

The purpose of the present invention is to provide a highly hydrophilic synthetic fiber. The present invention pertains to a synthetic fiber in which (a) mannosylerythritol lipid (MEL) and (b) at least one glycerin compound selected from the group consisting of (poly)glycerin, (poly)glycerin fatty acid ester, and (poly)glycerin alkylene oxide adduct are adhered to the surface of the fiber.

Description

Synthetic fibers, fiber treatment agents, and their uses

[0001] Disclosed are techniques relating to synthetic fibers, fiber treatments, and their use.

[0002] Compared to natural fibers, synthetic fibers have superior mechanical properties and chemical resistance, and are therefore used primarily in the form of nonwoven fabrics for applications such as liquid-impregnated sheets for wipes, wet tissues, and face masks, as well as top sheets for various hygiene products such as cosmetic and medical patches, disposable diapers, and sanitary napkins.

[0003] However, synthetic fibers, particularly those containing polyolefin resins such as polyethylene resin and polypropylene resin (sometimes referred to as polyolefin fibers), are less hydrophilic and more hydrophobic than natural fibers such as cotton and cellulose-based fibers such as rayon. Therefore, when using synthetic fibers as the liquid-impregnated sheets or top sheets for sanitary products, it is necessary to improve the hydrophilicity of the synthetic fibers. Various methods have been reported for improving the hydrophilicity of synthetic fibers, one of which is to treat the fibers with a fiber treatment agent containing a lactate salt and then adhere (poly)glycerin to the fiber surface (Patent Document 1).

[0004] Furthermore, in cosmetic and medical patches, top sheets for sanitary products, and the like, moisturizing properties are sometimes required to alleviate dryness of the skin in the areas that come into contact with the skin.

[0005] JP 2012-57275 A

[0006] One objective is to provide synthetic fibers with improved properties compared to conventional synthetic fibers, and fiber treatment agents therefor, such as synthetic fibers with improved hydrophilicity and improved moisture retention, and fiber treatment agents therefor.

[0007] The present inventors have discovered that by using a glycerin compound and mannosylerythritol lipid (MEL) in a fiber treatment agent and treating synthetic fibers with this fiber treatment agent, it is possible to impart moisture retention, hydrophilicity, and other properties to the synthetic fibers. Furthermore, while it has been suggested that blending a surfactant having a lipopeptide structure, such as surfactin, sophorolipid, rhamnolipid, or MEL, into a fiber treatment agent that is substantially free of lactate significantly reduces the hydrophilicity-imparting effect of the fiber treatment agent (Comparative Examples 11 to 16 in Patent Document 1), the present inventors have discovered that blending MEL into a fiber treatment agent containing a glycerin compound improves the hydrophilicity-imparting effect of the fiber treatment agent, even if the fiber treatment agent is substantially free of lactate. The present inventors have completed the following representative inventions.

[0008] Item 1. A synthetic fiber having (a) mannosylerythritol lipid (MEL), and (b) at least one glycerin compound selected from the group consisting of (poly)glycerin, (poly)glycerin fatty acid esters, and alkylene oxide adducts of (poly)glycerin attached to its surface. Item 2. The synthetic fiber according to Item 1, wherein the amounts of components (a) and (b) attached to the fiber are 0.05 to 10% by mass and 0.01 to 1% by mass, respectively, based on the mass of the synthetic fiber. Item 3. Item 3. The synthetic fiber according to Item 1 or 2, wherein the MEL is at least one selected from the group consisting of mannosylerythritol lipid A (MEL-A), mannosylerythritol lipid B (MEL-B), mannosylerythritol lipid C (MEL-C), mannosylerythritol lipid D (MEL-D), triacyl forms of MEL-A, triacyl forms of MEL-B, triacyl forms of MEL-C, and triacyl forms of MEL-D. Item 4. Synthetic fibers having a fiber treatment agent adhered to the fiber surface, the fiber treatment agent comprising: (a) mannosylerythritol lipid (MEL); and (b) at least one glycerin compound selected from the group consisting of (poly)glycerin, (poly)glycerin fatty acid ester, and alkylene oxide adduct of (poly)glycerin, the total mass of components (a) and (b) being 40 mass% or more of the entire fiber treatment agent, and the mass of component (a) being 33 to 99.5 mass% of the total mass of components (a) and (b). Item 4. The synthetic fiber according to Item 4, wherein MEL is one or more selected from the group consisting of mannosylerythritol lipid A (MEL-A), mannosylerythritol lipid B (MEL-B), mannosylerythritol lipid C (MEL-C), mannosylerythritol lipid D (MEL-D), triacyl forms of MEL-A, triacyl forms of MEL-B, triacyl forms of MEL-C, and triacyl forms of MEL-D. Item 6. A fiber assembly containing 50 mass% or more of the synthetic fiber according to any one of Items 1 to 5. Item 7. A skin-contact product, comprising the fiber assembly according to Item 6 in a skin-contact portion of the product, the fiber assembly being a nonwoven fabric. Item 8. The skin-contact product according to Item 7, wherein the skin-contact product is a hygiene product.Item 9. A fiber treatment agent comprising: (a) mannosylerythritol lipid (MEL), and (b) at least one glycerin compound selected from the group consisting of (poly)glycerin, (poly)glycerin fatty acid ester, and alkylene oxide adduct of (poly)glycerin, wherein component (a) accounts for 33 to 99.5% by mass based on the total mass of components (a) and (b). Item 10. The fiber treatment agent according to Item 9, wherein the total mass of components (a) and (b) is 40% by mass or more of the fiber treatment agent.

[0009] In one embodiment, a synthetic fiber with excellent hydrophilicity is provided. In one embodiment, a synthetic fiber with moisture retention is provided. In one embodiment, a fiber treatment agent capable of imparting hydrophilicity to a synthetic fiber is provided. In one embodiment, a fiber treatment agent capable of imparting hydrophilicity and moisture retention to a synthetic fiber is provided. In one embodiment, a fiber treatment agent whose hydrophilicity-imparting effect is enhanced by MEL is provided.

[0010] The following description will focus on the representative inventions mentioned above.

[0011] The synthetic fiber has the above-mentioned components (a) and (b) attached to its surface. Component (a) is mannosylerythritol lipid (MEL). Component (b) is at least one glycerin compound selected from the group consisting of (poly)glycerin, (poly)glycerin fatty acid esters, and alkylene oxide adducts of (poly)glycerin.

[0012] (Component (a); MEL) The structure of MEL is shown in general formula (1).

[0013]

[0014] (In general formula (1), substituent R １ are aliphatic acyl groups having 2 to 24 carbon atoms, which may be the same or different, and the substituent R ２ and R ３ are the same or different acetyl groups or hydrogen atoms.

[0015] In general formula (1), substituent R １are aliphatic acyl groups which may be the same or different and have 2 to 24 carbon atoms, preferably 2 to 20 or 4 to 24 carbon atoms, more preferably 4 to 18 carbon atoms, and even more preferably 6 to 14 carbon atoms.

[0016] MEL is classified into four types based on the presence or absence of acetyl groups at the 4- and 6-positions of mannose: mannosylerythritol lipid A (MEL-A), mannosylerythritol lipid B (MEL-B), mannosylerythritol lipid C (MEL-C), and mannosylerythritol lipid D (MEL-D).

[0017] MEL-A is a group represented by the general formula (1) in which the substituent R ２ and R ３ are both acetyl groups. MEL-B is a group represented by the general formula (1) ２ is an acetyl group, and the substituent R ３ is a hydrogen atom. MEL-C is a group represented by the general formula (1) ２ is a hydrogen atom, and the substituent R ３ is an acetyl group. MEL-D is a group represented by the general formula (1) in which the substituent R ２ and R ３ are both hydrogen atoms.

[0018] The substituent R in the above MEL-A to MEL-D １ The number of carbon atoms in the substituent R varies depending on the number of carbon atoms in the fatty acids constituting the triglyceride, which is the fat or oil contained in the MEL-producing medium, and the degree of assimilation of the fatty acids by the MEL-producing bacteria used. In addition, when the triglyceride has an unsaturated fatty acid residue, if the MEL-producing bacteria do not assimilate the double bond portion of the unsaturated fatty acid, the substituent R １ As is clear from the above explanation, the resulting MEL usually contains an unsaturated fatty acid residue as a substituent R １ The fatty acid residue moiety is in the form of a mixture of compounds with different structures.

[0019] (Triacylated MEL) The structure of the triacylated MEL, that is, triacylmannosylerythritol lipid (sometimes referred to as triacyl MEL), is shown in general formula (2) or (3).

[0020]

[0021]

[0022] (In the general formulas (2) and (3), the substituent R １ are aliphatic acyl groups having 2 to 24 carbon atoms, which may be the same or different, and the substituent R ２ are the same or different acetyl groups or hydrogen atoms, and the substituents R ３ are aliphatic acyl groups having 2 to 24 carbon atoms, which may be the same or different.

[0023] In the general formulas (2) and (3), the substituent R １ are aliphatic acyl groups which may be the same or different and have 2 to 24 carbon atoms, preferably 2 to 20 or 4 to 24, more preferably 4 to 18, and even more preferably 6 to 14 carbon atoms; ２ are the same or different hydrogen atoms or acetyl groups, and the substituents R ３ is an aliphatic acyl group having 2 to 24 carbon atoms, preferably 2 to 20 or 4 to 24 carbon atoms, more preferably 4 to 18 carbon atoms, and even more preferably 6 to 14 carbon atoms.

[0024] Like MEL, triacyl MEL is classified into four types, triacyl MEL-A, triacyl MEL-B, triacyl MEL-C, and triacyl MEL-D, based on the presence or absence of acetyl groups at the 4- and 6-positions of mannose.

[0025] The triacylated form of MEL can be obtained, for example, from the culture medium of a MEL-producing bacterium. Alternatively, the triacylated form of MEL can be produced by reacting MEL with various vegetable oils using an enzyme.

[0026] MEL is, for example, one or more selected from the group consisting of mannosylerythritol lipid A (MEL-A), mannosylerythritol lipid B (MEL-B), mannosylerythritol lipid C (MEL-C), mannosylerythritol lipid D (MEL-D), triacyl forms of MEL-A, triacyl forms of MEL-B, triacyl forms of MEL-C, and triacyl forms of MEL-D.

[0027] The MEL is preferably one or more selected from the group consisting of MEL-A and MEL-B, and more preferably MEL-B. As MEL-B, MEL-B having a structure represented by general formula (4) or (5) is preferred.

[0028]

[0029]

[0030] (In the general formulas (4) and (5), the substituent R １ are aliphatic acyl groups having 4 to 24 carbon atoms, which may be the same or different.

[0031] In the general formulas (4) and (5), the substituent R １ may be the same or different and are aliphatic acyl groups having 4 to 24 carbon atoms, preferably 4 to 18 carbon atoms, and more preferably 6 to 14 carbon atoms.

[0032] The MEL may be used alone, or two or more types of MEL may be used in combination.

[0033] The MEL used in the present invention is not particularly limited, and may be, for example, commercially available MEL, MEL produced by a conventionally known production method, etc. For example, MEL (MEL-A, MEL-B, MEL-C) can be produced by culturing a microorganism capable of producing MEL (MEL-producing microorganism), such as Pseudozyma antarctica (NBRC 1073), Pseudozyma tsukubaensis, Pseudozyma hubeiensis, Pseudozyma graminicola, or Pseudozyma sp., according to a conventional method.

[0034] (Component (b); Glycerin Compound) Component (b) is at least one glycerin compound selected from the group consisting of (poly)glycerin, (poly)glycerin fatty acid ester, and alkylene oxide adduct of (poly)glycerin. Here, (poly)glycerin means monoglycerin, polyglycerin, or a mixture of both. As the polyglycerin, one having an average degree of polymerization of 2 to 30 is preferably used, and one having an average degree of polymerization of 2 to 15 is more preferably used. Specific examples of polyglycerin include diglycerin, tetraglycerin, hexaglycerin, octaglycerin, and decaglycerin.

[0035] (Poly)glycerin fatty acid esters are esters of (poly)glycerin and fatty acids, and include monoesters, diesters, and triesters. In the (poly)glycerin fatty acid esters, the fatty acid component includes, for example, those derived from fatty acids having 10 to 22 carbon atoms, preferably 12 to 18 carbon atoms. The fatty acid may be saturated or unsaturated. Specific examples include saturated fatty acids such as capric acid, lauric acid, tridecylic acid, myristic acid, pentadecylic acid, palmitic acid, heptadecylic acid, stearic acid, isostearic acid, nonadecanoic acid, arachic acid, and behenic acid, and unsaturated fatty acids such as oleic acid. As component (b), polyglycerin monofatty acid esters in which a fatty acid having 10 to 22 carbon atoms is ester-bonded to a polyglycerin having a degree of polymerization of 2 to 15 is preferably used, and polyglycerin monolaurate in which a fatty acid having 12 carbon atoms (lauric acid) is ester-bonded to a polyglycerin having a degree of polymerization of 6 to 12 is particularly preferably used.

[0036] The (poly)glycerin used in (poly)glycerin fatty acid esters is generally produced by a glycerin polymerization method using glycerin-related substances such as (mono)glycerin, glycidol, or epichlorohydrin as raw materials, in which (mono)glycerin is dehydrated and condensed to increase the degree of polymerization of (poly)glycerin, as well as by other production methods such as the glycidol method, the epichlorohydrin method, or the diglycerin crosslinking method. When producing (poly)glycerin using these production methods, not only linear (poly)glycerin with the desired degree of polymerization but also cyclic (poly)glycerin having 6-membered and 8-membered rings may be produced as by-products and may be contained in the polymerized (poly)glycerin. Furthermore, (poly)glycerin with a low degree of polymerization, which differs from the desired degree of polymerization, may also be produced as by-products and may be contained in the (poly)glycerin. Among these, cyclic (poly)glycerin is considered to have low hydrophilicity and is also known to be highly irritating to the human body, so its content is preferably as low as possible.

[0037] The average degree of polymerization of (poly)glycerol refers to the average degree of polymerization determined from the hydroxyl value used for commonly available (poly)glycerols. The content of cyclic compounds contained in (poly)glycerol can be analyzed using a liquid chromatograph mass spectrometer (LC / MS) or the like.

[0038] In the alkylene oxide adduct of (poly)glycerin, the average number of moles of alkylene oxide added is, for example, 2 to 30, preferably 4 to 24, and more preferably 8 to 20. As the alkylene oxide in the alkylene oxide adduct of (poly)glycerin, for example, an alkylene oxide having 2 to 4 carbon atoms is used. Specific examples thereof include ethylene oxide, propylene oxide, and butylene oxide. As the alkylene oxide adduct of (poly)glycerin, an alkylene oxide adduct of diglycerin obtained by adding an alkylene oxide to diglycerin is preferably used, and a propylene oxide adduct is particularly preferably used. The average number of moles added of the propylene oxide adduct is, for example, within the range of the average number of moles added described above, and is preferably 9 to 14.

[0039] The amount of component (a) attached to the surface of the synthetic fiber can be, for example, 0.05% by mass or more, 0.1% by mass or more, or 0.3% by mass or more, and can be, for example, 10% by mass or less, 5% by mass or less, 3% by mass or less, or 1% by mass or less, relative to the mass of the synthetic fiber. In one embodiment, the amount of component (a) attached to the fiber is, for example, 0.05 to 10% by mass, preferably 0.1 to 5% by mass, and more preferably 0.3 to 3% by mass.

[0040] The amount of component (b) attached to the surface of the synthetic fiber is not particularly limited as long as the effect is exhibited, but can be, for example, 0.01% by mass or more, 0.05% by mass or more, or 0.1% by mass or more, and can be, for example, 1% by mass or less, 0.8% by mass or less, or 0.5% by mass or less, relative to the mass of the synthetic fiber. In one embodiment, the amount of component (b) attached to the fiber is, for example, 0.01 to 1% by mass, preferably 0.05 to 0.8% by mass, and more preferably 0.1 to 0.5% by mass. The amount of attached fiber refers to the amount of component (a) or (b) attached relative to the mass of the final synthetic fiber in a dried state.

[0041] One embodiment of the synthetic fiber is a synthetic fiber having a fiber treatment agent adhered to the fiber surface, the fiber treatment agent comprising (a) mannosylerythritol lipid (MEL) and (b) at least one glycerin compound selected from the group consisting of (poly)glycerin, (poly)glycerin fatty acid ester, and alkylene oxide adduct of (poly)glycerin, the total mass of components (a) and (b) being 40 mass% or more with respect to the entire fiber treatment agent, and the mass of component (a) being 33 to 99.5 mass% with respect to the total mass of components (a) and (b).

[0042] In one embodiment, a fiber treatment agent containing components (a) and (b) is prepared so that, when the combined mass of components (a) and (b) is taken as 100 mass%, component (a) is contained in an amount of, for example, 33 to 99.5 mass%, preferably 50 to 90 mass%, and more preferably 60 to 80 mass%. In one embodiment, the amount of component (b) may be any amount that results in the amount of component (a) falling within the above range; for example, when component (a) is 33 mass%, component (b) is 67 mass%, and when component (a) is 67 mass%, component (b) is 33 mass%. Amounts of components (a) and (b) within the above ranges are advantageous in terms of the hydrophilicity and moisture retention imparted to synthetic fibers, as well as fiber processability, for example, the ability to suppress static electricity during the carding step of fiber processing.

[0043] In one embodiment, the combined mass of components (a) and (b) in the fiber treatment agent accounts for, for example, 40% by mass or more, 50% by mass or more, 60% by mass or more, 70% by mass or more, 80% by mass or more, 85% by mass or more, 90% by mass or more, 95% by mass or more, or 97% by mass or more of the entire treatment agent. When other components are mixed with components (a) and (b) to prepare the fiber treatment agent, the other components may be selected from the components blended in the fiber treatment agent depending on the desired hydrophilicity, moisture retention, fiber processability, and other performance of the synthetic fiber to be obtained. Therefore, the fiber treatment agent may contain other hydrophilic components, other moisturizing components, components for improving fiber processability, etc., as long as the effects of the present invention are not impaired. In one embodiment, however, it is preferred that the fiber treatment agent does not contain salts of lactic acid and metals (e.g., potassium lactate, sodium lactate, magnesium lactate, calcium lactate, aluminum lactate).

[0044] Components other than components (a) and (b) that may be contained in the fiber treatment agent may be components commonly used in fiber treatment agents, specifically, for example, various tocopherols such as α-tocopherol, β-tocopherol, γ-tocopherol, and δ-tocopherol, various carotenoids such as β-carotene, lycopene, lutein, and astaxanthin, fat-soluble antioxidants such as ubiquinone (ubiquinol, ubidecarenone, CoQ10), α-lipoic acid (lipoic acid, thioctic acid), BHT (dibutylhydroxytoluene), and BHA (butylhydroxyanisole), ascorbic acid, isoascorbic acid, catechin, catechin gallate, epigallocatechin gallate, epigallocatechin, epicatechin gallate, epicatechin, gallocatechin gallate, and gallocatechin. Various catechins such as, anthocyanins, tannins, quercetin (including various glycosides such as rutin and quercitrin, enzyme-treated isoquercitrin, etc., and those that have been chemically treated), myricitrin, myricetin, and various flavonoids such as isoflavones, various phenolic acids such as chlorogenic acid, ellagic acid, and curcumin, water-soluble antioxidants such as polyphenols such as apple polyphenols and cocoa mass polyphenols, plant-derived essential oils such as phytoncides, hiba oil, and hinokitiol, and aromatic functional agents such as herb oils, as well as deodorants, antibacterial agents, allergen inactivators, heat-absorbing agents, far-infrared heat-retaining agents, etc.

[0045] Alternatively, a surfactant other than component (a) may be added to the fiber treatment agent. When a surfactant other than component (a) is added, one or more surfactants selected from known surfactants, such as nonionic surfactants such as sugar esters (also called "polyhydric alcohol esters"), fatty acid esters, alcohols, alkylphenols, polyoxyethylene-polyoxypropylene block polymers, alkylamines, bisphenols, polyaromatic rings, silicones, fluorines, and vegetable oils, anionic surfactants such as sulfates, sulfonates, carboxylic acids, and phosphates, cationic surfactants such as ammonium and benzalkonium, and amphoteric surfactants such as betaines and glycines, may be added. In one embodiment, it is preferable to add a biosurfactant (other than component (a)), which is a surfactant derived from a living organism such as a microorganism. This is because such a surfactant derived from a living organism is considered to be less irritating to the skin, similar to component (a). Biosurfactants include surfactants having a lipopeptide structure (also called amino acid type or acyl peptide type), glycolipid type (also called sugar type) biosurfactants such as trehalose lipid and cellobiose lipid, as well as phospholipid-based, fatty acid-based and polymer compound-based biosurfactants, which can be used alone or in combination of two or more types.

[0046] In addition to the other components commonly used in the above-mentioned fiber treatment agent, various functional agents usable in cosmetics may be added to the fiber treatment agent as components other than components (a) and (b), as long as they do not impair the effects of the present invention, such as functional agents that enhance the synthesis of hyaluronic acid or activate cells to exert anti-aging effects (anti-aging effects); functional agents that inhibit or suppress the activity of tyrosinase to suppress melanin production and thus exert whitening effects; functional agents that maintain skin moisture to exert moisturizing and emollient effects on the skin; other functional agents with UV protection and UV care effects, functional agents with anti-inflammatory effects, and functional agents with irritation-relieving effects. For example, chitin, chitosan, and chitin and chitosan derivatives derived therefrom (e.g., carboxymethylchitin, carboxymethylchitosan) are functional agents usable in cosmetics, and when added, they can exert antibacterial and moisturizing effects. By adding various functional agents that can be used in cosmetics, the synthetic fiber and fiber assembly of the present invention can increase the added value of products that come into direct contact with the skin for long periods of time, such as top sheets and cosmetic-impregnated sheets for hygiene products such as disposable diapers and sanitary napkins.

[0047] The fiber treatment agent is preferably used so as to achieve the above-mentioned fiber deposition amounts of components (a) and (b).

[0048] The synthetic fibers may be made of, for example, a thermoplastic resin. Specific examples of the thermoplastic resin include polyolefin resins such as polyethylene (including high-density, low-density, and linear low-density polyethylene), polypropylene, polybutene, polybutylene, polymethylpentene resin, polybutadiene, ethylene copolymers (e.g., ethylene-α-olefin copolymers), propylene copolymers (e.g., propylene-ethylene copolymers), ethylene-vinyl alcohol copolymers, ethylene-vinyl acetate copolymers, ethylene-(meth)acrylic acid copolymers, and ethylene-methyl(meth)acrylate copolymers; polyester resins such as polyethylene terephthalate, polybutylene terephthalate, polytrimethylene terephthalate, polyethylene naphthalate, polylactic acid, polybutylene succinate, and copolymers thereof; polyamide resins such as nylon 66, nylon 12, and nylon 6; acrylic resins; engineering plastics such as polycarbonate, polyacetal, polystyrene, and cyclic polyolefins; mixtures thereof; and elastomer resins thereof.

[0049] Synthetic fibers may be of any shape, such as a single fiber composed of one resin or a mixture of multiple resins, or a composite fiber composed of two or more components. The composite fibers may be, for example, sheath-core composite fibers, eccentric sheath-core composite fibers, side-by-side composite fibers, islands-in-the-sea composite fibers, or splittable composite fibers in which resin components resembling citrus fruit bunches are arranged alternately. The cross-sectional shape of the synthetic fibers may also be any shape. Thus, synthetic fibers may be synthetic fibers with a commonly obtained circular (e.g., perfect circle) cross section, or synthetic fibers with a noncircular cross section, i.e., fibers with irregular cross sections. Examples of cross-sectional shapes of fibers with irregular cross sections include polygonal, elliptical, flat, multilobal (specifically, multilobal with 3 to 32 lobes) shapes having multiple branches on the fiber surface, star-shaped, C-shaped, Y-shaped, W-shaped, cross-shaped, and well-shaped. Furthermore, as described above, synthetic fibers, whether they are single fibers or composite fibers, and / or whether the cross-sectional shape of the fiber is circular or irregular, may be so-called solid fibers, which do not have continuous cavities in the longitudinal direction of the fiber cross section, or so-called hollow fibers, which have one or more continuous cavities in the longitudinal direction.

[0050] When the fiber is a conjugate fiber having a core component and a sheath component (including those with an eccentric structure), it is preferable to select resins constituting the sheath component and the core component so that the melting point of the sheath component is equal to or less than the melting point of the core component - 10° C. Such a combination makes it possible to obtain a thermally adhesive conjugate fiber in which the sheath component can be used as a thermally adhesive component.

[0051] As the sheath component of the core-sheath composite fiber, low-melting point resins such as polyethylene (including those made from crude oil-derived ethylene such as naphtha as well as those polymerized from natural product-derived, so-called biomass-derived, raw materials, such as high-density polyethylene, low-density polyethylene, and linear low-density polyethylene, including, but not limited to, polyethylene polymerized with known catalysts such as Ziegler-Natta catalysts and metallocene catalysts) can be used. Preferred combinations (core / sheath) of core-sheath type composite fibers include polypropylene / high-density polyethylene, polypropylene / low-density polyethylene, polypropylene / linear low-density polyethylene, polyethylene terephthalate / high-density polyethylene, polyethylene terephthalate / low-density polyethylene, polyethylene terephthalate / linear low-density polyethylene, polypropylene / ethylene-propylene copolymer, polyethylene terephthalate / ethylene-propylene copolymer, polylactic acid / polyethylene, polylactic acid / polybutylene succinate, and polylactic acid / polybutylene succinate adipate.

[0052] When synthetic fibers are obtained as thermally adhesive core-sheath composite fibers, the core component / sheath component conjugation ratio (volume ratio) is preferably 2 / 8 to 8 / 2, taking into consideration the spinnability, adhesiveness, and processability of the fibers, and a ratio of 3 / 7 to 7 / 3 is advantageous in terms of carding ease and thermal adhesiveness of the fibers.

[0053] The fiber treatment agent can impart good hydrophilicity to synthetic fibers, and therefore can provide a significant hydrophilicity-imparting effect to fibers whose fiber surfaces are made of hydrophobic thermoplastic resins, particularly to fibers whose fiber surfaces are made of polyethylene, polypropylene, copolyesters, ethylene-based copolymers, and / or propylene-based copolymers.

[0054] The fiber fineness is preferably 0.3 to 20 dtex, more preferably 0.3 to 10 dtex. The fineness of synthetic fibers is appropriately selected depending on the application for which the fibers are to be used. For example, when used in top sheets for sanitary products, the fineness is preferably 0.5 to 8 dtex, more preferably 0.7 to 7 dtex, and particularly preferably 1 to 7 dtex. When synthetic fibers are used in wipers or wet tissues, the fineness is preferably 0.5 to 10 dtex. Furthermore, when synthetic fibers are used in cosmetic-impregnated sheets such as face masks, and as base fabrics for cosmetic and medical patches, the fineness is preferably 0.3 to 5 dtex. A fineness within the above range is advantageous in terms of fiber strength and flexibility when formed into a fiber assembly (e.g., a nonwoven fabric).

[0055] In one embodiment, the synthetic fibers are obtained by treating the synthetic fibers with a fiber treatment agent comprising, for example, components (a) and (b). In one embodiment, the synthetic fibers are obtained by treating the synthetic fibers with component (b) and then with component (a).

[0056] For example, a resin, which is the raw material for the synthetic fiber to be processed, is melt-spun using a known melt spinning machine with an appropriate spinning nozzle and spinning temperature depending on the fiber form to be obtained. The spun filament (undrawn yarn) is then drawn as necessary. The drawing method and conditions used during drawing are not particularly limited and are appropriately set depending on the type of resin, the combination of resins in the case of composite fibers, and the fiber performance to be obtained. For example, drawing is performed in hot water, hot air, or a heat medium at a drawing temperature of 60 to 110°C and a draw ratio of 2.0 to 8.0. The drawing method is not particularly limited, and known drawing processes can be used, such as wet drawing, in which drawing is performed while heating in a high-temperature liquid such as hot water or hot water; dry drawing, in which drawing is performed while heating in a high-temperature gas or with a high-temperature metal roll; and steam drawing, in which drawing is performed while heating the fiber in steam at 100°C or higher at normal or pressurized pressure.

[0057] After the filaments are drawn, a fiber treatment agent is applied to the filaments. Specifically, a solution of the fiber treatment agent diluted with water or another solvent (hereinafter also referred to as the "treatment liquid") is applied to the surface of the drawn filaments, and the filaments are then dried to evaporate the water (or other solvent) from the applied treatment liquid. This process results in the fiber treatment agent being applied to the dried filaments. There are no particular limitations on the method for applying the treatment liquid to the fiber surface, and it can be applied by, for example, a known spraying method, impregnation method, or roll touch method. The dried filaments are cut to a predetermined length as needed and provided as short fibers or staple fibers with fiber lengths of approximately 2 to 100 mm, or as long fibers (continuous fibers). Alternatively, the filaments can be cut to the desired length and then treated with the fiber treatment agent.

[0058] The drawn filaments are crimped, if necessary, by a crimping device to give a crimp number of 10 to 25 crimps per 25 mm and a crimp rate of about 8 to 25%. When giving crimps, it is preferable to apply a treatment liquid to the filaments before or simultaneously with giving crimps.

[0059] The synthetic fibers of the present invention are not limited to those obtained by applying the fiber treatment agent during the fiber production process, but also include those to which the fiber treatment agent has been applied during the production of a fiber assembly using the synthetic fibers. For example, the synthetic fibers of the present invention can be obtained by obtaining a fiber assembly such as a nonwoven fabric from untreated synthetic fibers or synthetic fibers to which another fiber treatment agent has been applied, as described below, and then applying a treatment agent to at least some of the fiber surfaces of the synthetic fibers constituting the fiber assembly, such as by spraying or impregnating the fiber assembly with a treatment agent obtained by adjusting the contents of components (a) and (b). Alternatively, the fiber treatment agent may be applied at a stage prior to the formation of the fiber assembly (e.g., to a fiber web for producing a nonwoven fabric, or to a spun yarn for woven or knitted fabrics obtained by spinning the fibers).

[0060] The synthetic fibers obtained by the above method (when the fiber treatment agent is applied during the production of a fiber assembly, the synthetic fibers are untreated or have another fiber treatment agent applied thereto) are processed into known fiber assemblies, such as woven or knitted fabrics, net-like materials, nonwoven fabrics, etc., and used. The fiber assemblies contain, for example, 50% by mass or more, 75% by mass or more, preferably 90% by mass or more, and more preferably 100% by mass of the synthetic fibers of the present invention. The synthetic fibers of the present invention are particularly preferably used to produce nonwoven fabrics. Nonwoven fabrics are produced by preparing a fiber web and then bonding and / or entangling the fibers to integrate them. The form of the fiber web is not particularly limited, and may be any fiber web, such as a parallel web, semi-random web, or cross web made of staple fibers; a wet-laid web or air-laid web made of short fibers; a spunbonded web or meltblown web made of long fibers; or a fiber web obtained by electrospinning (also known as electrostatic spinning). For applications where softness and feel are important, nonwoven fabrics are preferably made using webs made from staple fibers.

[0061] In the production of nonwoven fabrics, the method for integrating the fibers of a fiber web is not particularly limited. For example, when the fibers are thermally adhesive sheath-core composite fibers, or when the fibers are used to form a nonwoven fabric together with thermally adhesive fibers (single fibers or sheath-core composite fibers), the fibers may be integrated by a thermal bonding method such as hot air blowing or thermal embossing. Alternatively, the fibers may be integrated by a mechanical entanglement method such as needle punching or hydroentanglement.

[0062] In one embodiment, when the synthetic fiber is a thermally adhesive sheath-core composite fiber, a nonwoven fabric is produced using a fiber web containing 50 mass%, 75 mass% or more, preferably 90 mass% or more, and more preferably 100 mass% of the fiber of the present invention, and after thermal bonding, the fibers in the nonwoven fabric are preferably thermally bonded by the sheath component of the composite fiber. Specifically, it is preferred that the sheath component of the composite fiber is softened or melted to bond the fibers to each other. Thermal bonding by softening or melting the sheath component is achieved by heat treatment using a hot embossing roll or hot air at a temperature equal to or higher than the softening point of the sheath component of the composite fiber and lower than the melting point of the core component.

[0063] In one embodiment, a hydroentanglement treatment method may be employed to integrate the fibers. The hydroentanglement treatment method may be combined with the thermal bonding method. The conditions for the hydroentanglement treatment are set according to the basis weight, softness, and functionality of the nonwoven fabric to be ultimately obtained. When openings are formed in the nonwoven fabric, it is preferable to set the conditions taking this into consideration. The hydroentanglement treatment may be carried out, for example, by spraying a columnar water stream at a water pressure of 1 to 20 MPa from a nozzle having orifices with a hole diameter of 0.05 to 0.5 mm arranged at intervals of 0.5 to 1.5 mm onto one or both sides of the fiber web, 1 to 8 times each.

[0064] The fiber assembly containing the fibers of the present invention may contain other fibers. The other fibers are not particularly limited and may be, for example, natural fibers such as cotton, silk, and wool, or regenerated fibers such as viscose rayon, cupra, and solvent-spun cellulose fibers (e.g., lentigned lyocell (registered trademark) and Tencel (registered trademark)). Alternatively, the other fibers may be synthetic fibers having a fiber treatment agent other than the specific fiber treatment agent adhered to their surface. Resins suitable for constituting the synthetic fibers and the form of the synthetic fibers are as described above, and therefore a detailed description thereof will be omitted here. Only one type of these fibers may be used, or two or more types may be used.

[0065] When the fiber assembly of the present invention is obtained in the form of a nonwoven fabric and used as a top sheet (surface material) for sanitary goods, the nonwoven fabric is preferably a thermally bonded nonwoven fabric. In other words, a fiber web with a desired basis weight is produced by carding or air-laying using only the synthetic fibers of the present invention or a mixture of these fibers with other fibers, and then entangled as necessary, followed by thermal bonding of the fibers to obtain a thermally bonded nonwoven fabric, which is preferably used as a surface material for sanitary goods. The nonwoven fabric may have a laminated structure of a fiber web containing (or consisting solely of) the fibers of the present invention and a fiber web consisting of other fibers. In either structure, the surface material for sanitary goods contains the fibers of the present invention in an amount of 50% by mass or more, 75% by mass or more, preferably 90% by mass or more, and more preferably 100% by mass, thereby enabling the rapid transfer of human or animal body fluids from the body to an absorbent.

[0066] The basis weight of the fiber assembly containing the fiber of the present invention is not particularly limited and is appropriately selected depending on the application. For example, when the fiber assembly of the present invention is used as a nonwoven fabric for the surface material of a sanitary product, the basis weight is 10 to 80 g / m ２ When the fiber assembly of the present invention is used as a nonwoven fabric for various wiping sheets for people, animals, and objects, such as wet tissues, wipers, and disposable hand towels, the basis weight is preferably 20 to 100 g / m ２ Furthermore, when the fiber assembly of the present invention is used as a nonwoven fabric for cosmetic-impregnated sheets such as face masks or cosmetic or medical patches, the basis weight is preferably 20 to 200 g / m ２ It is preferable to set the following.

[0067] When the fiber assembly containing the fibers of the present invention is provided as a nonwoven fabric, the nonwoven fabric is preferably incorporated into a skin-contact product. That is, the present invention also provides a skin-contact product that uses the nonwoven fabric at least in part. Here, "skin-contact product" refers to a product that is used in contact with the skin of a human or non-human animal. Specific examples of skin-contact products include: - Body fluid absorbent articles (specifically, disposable diapers for babies, disposable diapers for adults, sanitary napkins, panty liners, incontinence pads, interlabial pads, breast pads, sweat absorbent sheets, animal waste disposal materials, disposable diapers for animals, animal urine absorbent sheets, etc.) - Skin covering sheets (specifically, face masks, base fabrics for cosmetic and medical patches such as cooling and warming patches, wound protection sheets, nonwoven bandages, hemorrhoid pads, heating devices that are applied directly to the skin (e.g., disposable hand warmers), base fabrics for various animal patches, etc.) - Personal wipes (makeup remover sheets, antiperspirant sheets, diaper wipes, etc.), various animal wiping sheets, etc. - Others (e.g., disposable underwear, disposable clothing such as medical gowns, masks, animal wound protection clothing, fiber parts of adhesive bandages, bandages, medical gauze, etc.) The nonwoven fabric containing the fibers of the present invention may constitute part or all of these products. For example, in a body fluid absorbent article, only the surface material may be composed of a nonwoven fabric containing the fibers of the present invention. In addition, in a skin application sheet, only the part covering a particularly sensitive area may be composed of a nonwoven fabric containing the fibers of the present invention, or the entire skin application sheet may be composed of a nonwoven fabric containing the fibers of the present invention.

[0068] The present invention will be specifically described below with reference to examples, but the present invention is not limited to these.

[0069] (Preparation of Fiber Treating Agent) The following components (a) and (b) were used and mixed in the proportions (mass %) shown in Table 1 to prepare fiber treating agents.

[0070] [Component (a)] a-1: Mannosylerythritol lipid B (trade name: Ceramela (registered trademark), manufactured by Toyobo Co., Ltd.) a-2: Sodium surfactin (trade name: Kaneka Surfactin, manufactured by Kaneka Corporation) a-3: Sophorolipid (trade name: ACS Sophoro, manufactured by Allied Carbon Solution Co., Ltd.) [Component (b)] b-1: Decaglycerin monolaurate (trade name: ML750, manufactured by Sakamoto Pharmaceutical Industry Co., Ltd.) b-2: Polyoxypropylene diglycerin ether (average number of moles of propylene oxide added: 14) (trade name: SC-P1000, manufactured by Sakamoto Pharmaceutical Industry Co., Ltd.) b-3: Polyglycerin (an oil solution containing approximately 25% by mass of polyglycerin (trade name: TES8327, manufactured by Takemoto Oil & Fat Co., Ltd.) was used as a polyglycerin source)

[0071] Example 1 Using high-density polyethylene (trade name: Nipolon Hard OS02H, manufactured by Tosoh Corporation) having a melting point of 130°C before spinning, a melt flow rate of 20 g / 10 min measured in accordance with JIS K6922-1 at a temperature of 190°C and a mass of 2.16 kgf, and a density of 0.952, and polyethylene terephthalate (trade name: HY-01, manufactured by HENGYI) having a melting point of 260°C before spinning and an intrinsic viscosity (IV value) of 0.640 dl / g, polyethylene terephthalate resin and polyethylene resin were spun from a spinning nozzle with an outlet hole having a hole diameter of φ0.35 in a mass ratio of core component:sheath component = 60 / 40, and melt spinning was performed at a take-up speed of 1200 m / in to obtain a core-sheath type composite undrawn yarn having a fineness of 5.4 dtex.

[0072] The undrawn yarn was then subjected to a wet drawing treatment at a drawing temperature of 80°C and a draw ratio of 2.67 to obtain a drawn yarn. A treatment agent obtained by mixing two components in the mixing ratio shown in the Example 1 column of Table 1 was diluted with water to a treatment agent concentration of 8.0% by mass to obtain a treatment solution. The treatment solution was applied to the drawn yarn using a roller oiling device, and the yarn was then crimped using a crimping device (crimper). The yarn was then dried at 100°C for 15 minutes to evaporate moisture from the fiber surface and dry, and then cut to a fiber length of 44 mm using a cutter. This resulted in a core-sheath composite fiber with a fineness of 2.4 dtex, a fiber length of 44 mm, a number of crimps of 18 / 25 mm, and a crimp rate of 16%.

[0073] The resulting fiber was spun using a roller card to a weight of 30 g / m ２ A fiber web of the above formula was prepared, and the sheath component of the fiber was melted at a heat treatment temperature of 140° C. using a hot air blowing device, and the fibers of the fiber web were thermally bonded to each other to obtain a thermally bonded nonwoven fabric.

[0074] (Examples 2 to 7, Comparative Examples 1 to 6, Reference Examples 1 to 3) Fibers were obtained in the same manner as in Example 1, except that the fiber treatment agents used were prepared by mixing the components in the proportions shown in the columns for Examples 2 to 7, Comparative Examples 1 to 6, and Reference Examples 1 to 3 shown in Table 1, and thermally bonded nonwoven fabrics were produced. The amounts of the treatment agents attached to the fiber surfaces were determined by the method described above. The results are shown in Table 1. In Examples 6 and 7, fiber treatment agents were prepared using an oil containing 25% by mass of polyglycerin as the polyglycerin b-3, but the proportions and attachment amounts of component (b) in Table 1 are shown based on the amount of polyglycerin rather than the amount of oil.

[0075] (Measurement of the amount of fiber treatment agent attached) The adhesion rate of the treatment agent to the fiber surface was measured by a rapid extraction method using a rapid residual oil extractor (Soxtec™2055) manufactured by Foss Co., Ltd. First, the fibers treated with the fiber treatment agent, which were cut to a predetermined length, were dried in a hot air dryer (105°C x 30 minutes), and then passed through a fiber opener twice. After that, 8 g (W ｆ The cotton was packed into a metal tube (inner diameter 35 mm, length 75 mm, bottom of which was a 100 mesh plain woven wire mesh filter), and then immersed in an aluminum cup containing a solvent (90 ml) of ethanol / hexane (75 / 25). The aluminum cup (mass: W ｔｒａｙ The mass of the aluminum cup (W ｔｒａｙ The mass (W) of the aluminum cup with the fiber treatment agent remaining after the solvent had completely evaporated was measured after the aluminum cup had been thoroughly dried in a dryer (105°C x 10 minutes) and before the solvent was applied. ｆａｔ) was measured. After the above measurement, the amount of the treatment agent attached to the fiber surface relative to the fiber mass was calculated using the following formula. The amount of the treatment agent attached to the fiber surface in Example 1 was determined using the above method, and the amount of the treatment agent attached was 0.5 mass% relative to the fiber mass. This amount was multiplied by the contents (mass%) of components (a) and (b) in the fiber treatment agent to determine the amounts (mass%) of components (a) and (b) attached relative to the fiber mass, and these are shown in Table 1.

[0076]

[0077] (Evaluation of Hydrophilicity) The hydrophilicity of the obtained nonwoven fabrics of each Example and Comparative Example was evaluated. The evaluation of hydrophilicity was carried out by a run-off test (a test method recommended by EDNA (European Disposables and Nonwovens Association) and known as the EDNA RUN-OFF test), specifically according to the following procedure. First, the nonwoven fabric was cut into a sample measuring 36 cm in the longitudinal direction (machine direction) x 15 cm in the transverse direction. This nonwoven fabric sample was placed and fixed on a support table so that the longitudinal direction and the horizontal plane formed a 45-degree angle. At this time, filter paper Type 5A manufactured by Advantec Co., Ltd. was laid on the inclined surface of the support table, and five sheets of the nonwoven fabric sample to be measured were placed on top of it and fixed. The support table had a cross section of an approximately vertical isosceles triangle that formed a 45-degree angle with the horizontal plane. A total of 10 g of blue-colored saline solution was dropped from a position 1 cm above the top edge of the nonwoven fabric surface at a rate of 2 g / 10 seconds using a burette, and the position at which the saline solution was completely absorbed by the nonwoven fabric and the saline droplets disappeared from the nonwoven fabric surface was measured, and the distance that the saline droplets ran along the nonwoven fabric surface between that position and the position where the saline solution was dropped on the nonwoven fabric surface was calculated. For each example, 10 samples were used and the test was performed 10 times, and the average runoff values ​​(distance that ran) are shown in Table 1.

[0078] The shorter this distance, the more hydrophilic the nonwoven fabric is, and more specifically, the higher its ability to instantly absorb moisture.On the other hand, a nonwoven fabric with low hydrophilicity is less likely to absorb the dripped physiological saline solution, and the longer this distance becomes.

[0079] (Moisture retention evaluation) The moisture retention of the nonwoven fabrics obtained in the Examples, Comparative Examples, and Reference Examples was evaluated. Five subjects (men and women in their 30s and 40s) were included. The inner forearms of the subjects were washed five times with a commercially available detergent (product name: Charmy V Quick, manufactured by Lion Corporation). After that, the subjects were allowed to rest for 30 minutes in an environment of 22°C and 50% RH. Then, the moisture content of the stratum corneum on the inner forearms after washing with the commercially available detergent was measured using a Corneometer CM825 (Courage+Khazaka). Then, a nonwoven fabric (sample size: 3 cm x 3 cm) obtained in the Examples, Comparative Examples, or Reference Examples was applied to the inner forearms where the moisture content of the stratum corneum had been measured, and the moisture content of the stratum corneum was measured after 120 minutes of application. The moisture content of the stratum corneum before application was subtracted from the moisture content of the stratum corneum after application to calculate the increase in moisture content of the stratum corneum. The results are shown in Table 1.

[0080]

[0081] In Examples 1 to 7, the runoff values ​​were short, confirming good hydrophilicity, and the moisture retention was comparable to or better than that of Reference Example 2, demonstrating the moisture retention of a-1 (MEL) without impairing it. The small runoff value of 20.2 in Reference Example 1 confirmed that the glycerin compound has a hydrophilicity-imparting effect. On the other hand, the large runoff value of 193.1 in Reference Example 2 confirmed that a-1 (MEL) alone has almost no hydrophilicity-imparting effect. Nevertheless, comparing Example 1 with Reference Example 1, the combined use of a-1 (MEL) and a glycerin compound resulted in a smaller runoff value than the glycerin compound alone (Reference Example 1), confirming that the combined use improved the hydrophilicity of the fiber. Therefore, it was confirmed that the combined use of a glycerin compound and MEL not only imparted the moisture retention properties inherent to MEL to the fiber, but also improved the hydrophilicity-imparting effect of glycerin. In contrast, in comparison between Reference Example 1 and Comparative Examples 1 and 2, when other biosurfactants a-2 (sodium surfactin) and a-3 (sophorolipid) were used, the runoff value of the glycerin compound was greater than 20.2, confirming that the hydrophilicity-imparting effect of the glycerin compound was reduced.

Claims

1. Synthetic fibers composed of a fiber-adhesive agent bonded to the fiber surface, where the fiber-adhesive agent contains (a) liquid mannosilary tritol (MEL) and (b) at least one glycerol compound selected from a group consisting of (poly)glycerol, fatty acid esters (poly)glycerol and alkylene oxide adductors of (poly)glycerol. The total mass of component (a) and component (b) is 40% by mass or more on the basis of all fiber-adhesive agents and the mass of component (a) is 33 to 99.5% by mass on the basis of the total mass of component (a) and component (b).

2. Synthetic fibers under Protection 1 where MEL is at least one component selected from a group of components consisting of liquid mannosileritritol A (MEL-A), liquid mannosileritritol B (MEL-B), liquid mannosileritritol C (MEL-C), liquid mannosileritritol D (MEL-D), triacrylate MEL-A, triacrylate MEL-B, triacrylate MEL-C and triacrylate MEL-D.

3. Fiber assemblies containing synthetic fibers of Protection 1 or 2 in an amount of 50% by mass or more. 4.Skin contact products incorporating the fiber assembly of claim 3 in the skin contact portion of the skin contact product in which the fiber assembly is a non-woven fabric; 5. Skin contact products incorporating claim 4 in which the fiber assembly is a hygiene product; 6. Fiber-acting agents incorporating (a) liquid mannosileritol (MEL) and (b) at least one glycerol compound selected from the group of (poly)glycerol, fatty acid esters (poly)glycerol and alkylene oxide adducts of (poly)glycerol in which component (a) is present in amounts of 33 to 99.5% by mass based on the total mass of component (a) and component (b) and the total mass of component (a) and component (b) is 40% by mass or more of the fiber-acting agent;