Surface-modified fiber, method for producing same, and molded article using surface-modified fiber

Abstract

A surface-modified fiber comprising a fiber and a surface-modified layer covering at least a portion of the surface of the fiber, the surface-modified fiber being characterized in that: the surface-modified layer contains a compound having a hydrogen-bonding functional group; the amount of the surface-modified layer is 0.01-2.5 parts by mass per 100 parts by mass of the fibers used as the starting material.

Description

Technical Field

[0001] The present invention relates to a surface-modified fiber having excellent adhesiveness to resin and concrete, a method for producing the same, and a molded body using the surface-modified fiber. Background Art

[0002] For synthetic fibers such as polyvinyl alcohol and polyamide, since they are excellent in strength and durability, lightweight and inexpensive, they are used as fibers for reinforcing concrete and the like for the purpose of improving the strength of buildings and preventing cracking.

[0003] In addition, the above synthetic fibers are also used as fibers for reinforcing automobile tires, brake hoses, etc. When using the above fibers for this purpose, it is necessary to firmly bond the fibers to rubber, so surface-modified fibers with modified surfaces are used.

[0004] As a specific example of the above surface-modified fiber, Patent Document 1 discloses a fiber coated with branched polyethyleneimine in a proportion of about 0.2 to about 20% by mass relative to the total weight of the coated fiber.

[0005] In addition, Patent Document 2 describes a reinforcing fiber having a surface-modified layer covering at least a part of the surface of the coated fiber, etc., wherein the above surface-modified layer contains a specific polyamine compound.

[0006] Prior Art Documents

[0007] Patent Documents

[0008] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2022-511602

[0009] Patent Document 2: International Publication No. 2022 / 044460 Summary of the Invention

[0010] Problems to be Solved by the Invention

[0011] Although the above fibers with modified surfaces have shown certain performance in terms of adhesiveness and the like, there is still room for improvement. Specifically, the adhesive force of the fibers described in Patent Document 1 is insufficient and improvement is desired. The fibers described in Patent Document 2 have problems such as coloring because they are treated at a relatively high temperature. In addition, since the adhesiveness and the degree of adhesion between chemical fibers and resin are extremely low in general, it is necessary to develop a method for improving them.

[0012] The present invention has been completed in view of the above existing problems, and the present invention provides a surface-modified fiber having excellent adhesiveness to resin and concrete and capable of suppressing coloring, a method for producing the same, and a molded body using the surface-modified fiber.

[0013] Method for solving problems

[0014] In order to solve the above problems, the inventors of the present invention conducted in-depth research and found that by providing a surface modification layer containing a compound having a hydrogen bonding functional group on at least a part of the surface of the fiber, the adhesiveness between the fiber and the resin and between the fiber and the concrete can be improved, and thus the present invention was completed.

[0015] That is, the present invention relates to the following [1] to [6].

[0016] [1] A surface-modified fiber having a fiber and a surface modification layer covering at least a part of the surface of the fiber,

[0017] The surface modification layer contains a compound having a hydrogen bonding functional group, and the amount of the surface modification layer is 0.01 to 2.5 parts by mass with respect to 100 parts by mass of the fiber used as a raw material.

[0018] [2] The surface-modified fiber according to the above [1], wherein

[0019] The hydrogen bonding functional group is one or more selected from a hydroxyl group, a carboxyl group, a carboxylate group, an esterified product of a carboxyl group, a carboxylic anhydride group, a carbonyl group, an aldehyde group, an acetalized product of an aldehyde group, an amino group, and an amide group.

[0020] [3] The surface-modified fiber according to the above [1] or [2], wherein

[0021] The fiber is one or more fibers selected from polyamide fibers, polyvinyl alcohol fibers, polyester fibers, and regenerated cellulose fibers.

[0022] [4] The surface-modified fiber according to any one of the above [1] to [3], wherein

[0023] The parameter (YI) of the hue of the surface-modified fiber is 0 to 50.

[0024] [5] A method for manufacturing a surface-modified fiber, which is a method for manufacturing the surface-modified fiber according to any one of the above [1] to [4], and the method has the following steps (1) and (2):

[0025] [Step (1)]

[0026] A step of preparing a solution or dispersion of the compound having a hydrogen bonding functional group and attaching the solution or dispersion to the fiber;

[0027] [Step (2)]

[0028] A step of heat-treating the fiber coated with the solution or dispersion liquid under the conditions of 180 to 280 °C for 50 seconds or less.

[0029] [6] A molded body using the surface-modified fiber according to any one of the above [1] to [4].

[0030] Effects of the Invention

[0031] The present invention can provide surface-modified fibers having excellent adhesiveness to resins and concrete and capable of suppressing coloring, a method for producing the same, and a molded body using the surface-modified fibers. Detailed Description of the Invention

[0032] [Surface-Modified Fiber]

[0033] The surface-modified fiber of the present invention is a surface-modified fiber having a fiber and a surface-modified layer covering at least a part of the surface of the fiber.

[0034] The above surface-modified layer contains a compound having a hydrogen-bonding functional group, and the amount of the surface-modified layer is 0.01 to 2.5 parts by mass with respect to 100 parts by mass of the fiber used as a raw material.

[0035] In the present invention, since a surface-modified layer containing a compound having a hydrogen-bonding functional group is provided on at least a part of the fiber surface, a strong affinity is exhibited between the hydrogen-bonding functional group and the fiber, and between the hydrogen-bonding functional group and concrete and resin. As a result, the adhesiveness between the fiber and the resin, and between the fiber and the concrete is improved. In addition, since decomposition of the surface-modified layer hardly occurs, surface-modified fibers having excellent transparency can be obtained.

[0036] It should be noted that in the present invention, the "surface-modified layer covering at least a part of the surface of the fiber" may mean a mode in which the surface-modified layer exists on at least a part of the fiber surface in the form of a film or a layer, or a mode in which a component equivalent to the surface-modified layer is included in the raw material of the fiber and a component of the surface-modified layer exists on a part of the surface of the fiber itself.

[0037] <Surface-Modified Layer>

[0038] The surface-modified layer in the present invention is a layer containing a compound having a hydrogen-bonding functional group. In the present invention, by using a compound having a hydrogen-bonding functional group in the surface-modified layer, the adhesive force between the surface-modified fiber and the resin, and between the surface-modified fiber and the concrete can be improved.

[0039] It should be noted that in this specification, "hydrogen bond" refers to a bonding interaction formed between a hydrogen atom (donor) that is bonded to an atom with high electronegativity (such as O, N, S, etc.) and polarized positively and an atom with a lone pair of electrons that is polarized negatively (acceptor).

[0040] Examples of the above-mentioned hydrogen-bonding functional groups include: hydroxyl group, epoxy group, ether group, mercapto group, carboxyl group, carbonyl group, aldehyde group, amino group, imino group, imidazole group, urethane group, amide group, urea group, isocyanate group, nitrile group, silanol group, and their derivatives. In addition, as the carboxyl group, groups derived from monocarboxylic acids and groups derived from dicarboxylic acids can be cited. As derivatives of the carboxyl group, its salts, its esterified forms, its amidated forms, and its acid anhydrides can be cited. As derivatives of the aldehyde group, its acetalized forms can be cited. As derivatives of the silanol group, its esterified forms can be cited.

[0041] Among them, those preferably selected are one or more of the form of a salt of a hydroxyl group, a carboxyl group, a carboxylate group, an esterified form of a carboxyl group, an acid anhydride form of a carboxyl group, a carbonyl group, an aldehyde group, an acetalized form of an aldehyde group, an amino group, and an amide group. More preferably, one or more of a carboxyl group, a carbonyl group, an amino group, and an amide group are selected.

[0042] Examples of specific compounds having the above-mentioned hydrogen-bonding functional groups include: compounds having a hydroxyl group such as ethylene glycol, diethylene glycol, 1,2-propanediol, and 1,3-propanediol;

[0043] compounds having an amino group such as polyethyleneimine, polyallylamine, polyvinylamine, polydiallylmethylamine, polydiallylethylamine, and their salts;

[0044] compounds having an amide group such as polyvinylpyrrolidone, 2-pyrrolidone, N-methyl-2-pyrrolidone, N-hydroxyethyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, and ε-caprolactam;

[0045] compounds having a carboxyl group such as maleic acid, fumaric acid, citraconic acid, propiolic acid, and itaconic acid; and so on.

[0046] Among the above compounds having hydrogen-bonding functional groups, polyethyleneimine, polyallylamine, and polyvinylpyrrolidone are preferred. When using these compounds having hydrogen-bonding functional groups, the adhesiveness and the transparency of the surface modification layer are particularly improved.

[0047] The amount of the compound having a hydrogen-bonding functional group in the surface modification layer is preferably 70% by mass or more, more preferably 80% by mass or more, still more preferably 90% by mass or more, and substantially even more preferably 100% by mass. When the amount of the compound having a hydrogen-bonding functional group in the surface modification layer is within the above range, the adhesiveness between the fiber and the resin can be improved, and a surface-modified fiber excellent in transparency can be obtained.

[0048] From the viewpoint of improving the adhesiveness with the resin, the surface modification layer preferably covers the entire surface of the fiber, but substantially, it suffices to cover at least a part of the surface of the fiber. The specific amount of the surface modification layer covering the surface of the fiber is 0.01 to 2.5 parts by mass, preferably 0.05 to 2.0 parts by mass, more preferably 0.1 to 1.5 parts by mass, still more preferably 0.15 to 1.2 parts by mass, even more preferably 0.15 to 1.0 parts by mass, and particularly preferably 0.2 to 0.5 parts by mass with respect to 100 parts by mass of the fiber used as a raw material.

[0049] The above surface modification layer may or may not contain other components in addition to the above. Examples of other components include crosslinking agents, acids, bases, inorganic salts, organic salts, pigments, dyes, antioxidants, polymerization initiators, and plasticizers.

[0050] When the surface modification layer contains the above other components, from the viewpoint of improving the adhesive force with the resin, the content of the other components in the surface modification layer is preferably 20% by mass or less, more preferably 10% by mass or less, and still more preferably 5% by mass or less.

[0051] In the present invention, the parameter (YI) of the hue of the surface modification layer is preferably 0 to 50. When the parameter (YI) of the hue of the surface modification layer is within the above range, a surface-modified fiber excellent in transparency can be obtained. From this viewpoint, the parameter (YI) of the hue of the surface modification layer is more preferably 0 to 45, still more preferably 0 to 35, even more preferably 0 to 30, and particularly preferably 0 to 25.

[0052] The parameter (YI) of the hue of the surface modification layer in the present invention is the hue measured in accordance with JIS Z8722:2009, and specifically, it can be measured by the method described in the examples.

[0053] <Fiber>

[0054] The fiber used for the surface-modified fiber of the present invention is not particularly limited, and hydrophilic fibers and hydrophobic fibers can be used. It should be noted that in the present invention, "fiber" includes not only short fibers and long fibers, but also forms such as non-woven fabrics, fabrics, knitted fabrics, felts, and sponges.

[0055] As a hydrophilic synthetic fiber, a synthetic fiber composed of a thermoplastic resin having hydrophilic functional groups such as a hydroxyl group, a carboxyl group, a sulfonic acid group, and an amino group, and / or a hydrophilic bond such as an amide bond can be cited.

[0056] Specific examples of such thermoplastic resins include: polyvinyl alcohol resins, polyamide resins [aliphatic polyamides such as polyamide 6, polyamide 66, polyamide 11, polyamide 12, polyamide 610, polyamide 612, polyamide 9C (polyamide formed from nonanediamine and cyclohexanedicarboxylic acid), etc.; semi-aromatic polyamides synthesized from aromatic dicarboxylic acids and aliphatic diamines such as polyamide 9T (polyamide formed from nonanediamine and terephthalic acid); wholly aromatic polyamides synthesized from aromatic dicarboxylic acids and aromatic diamines such as poly(p-phenyleneterephthalamide), etc.], polyacrylamide resins, and the like.

[0057] Among them, polyvinyl alcohol resins and polyamide resins are preferred. The hydrophilic synthetic fibers can be used alone or in combination of two or more. In addition, for these hydrophilic synthetic fibers, in order to further improve hydrophilicity, the subsequent hydrophilization treatment can be further carried out, or it can be not carried out.

[0058] As hydrophilic natural fibers, natural cellulose fibers such as wood pulp such as kraft pulp, cotton pulp, and non-wood pulp such as straw pulp can be cited.

[0059] As hydrophilic regenerated fibers, regenerated cellulose fibers such as rayon, lyocell fiber, cuprammonium fiber, and polynosic fiber can be cited.

[0060] These natural fibers and regenerated fibers can be used alone or in combination of two or more. In addition, for these hydrophilic natural fibers and regenerated fibers, in order to further improve hydrophilicity, the subsequent hydrophilization treatment can be further carried out, or it can be not carried out.

[0061] The hydrophilic fiber only needs to have hydrophilicity at least on the surface. For example, it can be a fiber obtained by hydrophilizing the surface of a hydrophobic fiber, a core-sheath type composite fiber having a hydrophobic resin as the core and a hydrophilic resin as the sheath, etc., or it can be a non-composite fiber having a single structure without a core-sheath structure. For examples of the hydrophilic resin constituting the sheath, the description of the hydrophilic synthetic fiber can be cited. As the hydrophobic fiber formed from a hydrophobic resin, the hydrophobic fibers described later can be cited.

[0062] The hydrophilization treatment is not particularly limited as long as it chemically or physically imparts hydrophilic functional groups to the fiber surface. For example, it can be carried out by a method of modifying hydrophobic fibers formed from the hydrophobic resins described later using compounds or their derivatives containing hydrophilic functional groups such as isocyanate groups, epoxy groups, hydroxyl groups, amino groups, ether groups, aldehyde groups, carbonyl groups, carboxyl groups, and urethane groups, or by a method of modifying the surface by electron beam irradiation, etc.

[0063] In the present invention, hydrophobic fibers that cannot be firmly bonded to the resin in the prior art can also be used. Since hydrophobic fibers generally do not have polar functional groups on the fiber surface, the affinity with the bonding components described later is poor, and they cannot be firmly bonded to the resin. However, by providing a surface modification layer on the fiber surface as in the present invention, even hydrophobic fibers can be firmly bonded to the resin.

[0064] Examples of the hydrophobic fibers that can be used in the present invention include polyolefin fibers such as polyethylene and polypropylene, polyester fibers such as polyethylene terephthalate, and wholly aromatic polyester fibers. Among them, polyester fibers are preferred in terms of excellent manufacturing cost, strength, heat resistance, and durability.

[0065] In the present invention, among the above fibers, synthetic fibers and regenerated fibers are preferred, and one or more fibers selected from polyamide fibers, polyvinyl alcohol fibers, polyester fibers, and regenerated cellulose fibers are preferred.

[0066] It should be noted that in the present invention, one kind of fiber can be used alone, or two or more kinds can be used in combination.

[0067] The fineness of the single filament of the fiber used for the surface-modified fiber of the present invention is preferably 500~4500 dtex. When it is 500 dtex or more, it is easy to manufacture industrially. In addition, when it is 4500 dtex or less, it is easy to maintain the strength when the surface-modified fiber is used as a reinforcing material.

[0068] From the above viewpoints, the fineness of the single filament of the fiber used for the surface-modified fiber of the present invention is more preferably 500~4000 tex, and further preferably 1000~3000 tex.

[0069] [Manufacturing method of surface-modified fiber]

[0070] The surface-modified fiber of the present invention is preferably manufactured by a manufacturing method having the following steps (1) and (2). When manufacturing by the method having the following steps, it is possible to manufacture the surface-modified fiber while preventing the decomposition of the surface modification layer, so that it can have excellent adhesive strength and suppress coloring.

[0071] 〔Process (1)〕

[0072] A process of preparing a solution or dispersion of the above compound having a hydrogen-bonding functional group and attaching the above solution or dispersion to the above fiber

[0073] 〔Process (2)〕

[0074] A process of heat-treating the above fiber to which the above solution or dispersion is attached under the conditions of 180 to 280°C for 50 seconds or less

[0075] In the above process (1), there is no particular limitation on the solvent or dispersant for dissolving or dispersing the compound having a hydrogen-bonding functional group. From the viewpoints of storage stability and cost, water and water-soluble organic solvents are preferred. Examples of water-soluble organic solvents include monohydric alcohols having 1 to 8 carbon atoms such as methanol, ethanol, isopropanol, n-butanol, isoamyl alcohol, and tert-butanol; polyhydric alcohols such as ethylene glycol, diethylene glycol, and glycerol; ketones having 3 to 10 carbon atoms such as acetone, methyl ethyl ketone, diethyl ketone, and methyl isobutyl ketone; and organic solvents such as propylene carbonate in carbonate solvents, etc.

[0076] Among them, water and alcohols having 1 to 6 carbon atoms are more preferred, and water is further preferred.

[0077] When dissolving or dispersing the above compound having a hydrogen-bonding functional group in the above solvent or dispersant, the amount of the above compound having a hydrogen-bonding functional group is preferably 0.01 to 30 parts by mass, more preferably 0.05 to 20 parts by mass, further preferably 0.1 to 10 parts by mass, and even more preferably 0.1 to 5 parts by mass with respect to 100 parts by mass of the above solvent or dispersant. When the amount of the compound having a hydrogen-bonding functional group is within the above range with respect to 100 parts by mass of the solvent or dispersant, the compound having a hydrogen-bonding functional group can be uniformly attached to the fiber while suppressing the manufacturing cost.

[0078] In the above process (1), there is no particular limitation on the method of attaching the solution or dispersion of the compound having a hydrogen-bonding functional group to the fiber. For example, it is preferably carried out by one or more selected from dipping, roll coater, oiling roll, oiling guide, nozzle (spray) coating, and brush coating.

[0079] The temperature of the heat treatment in the above process (2) is preferably 180 to 280°C, more preferably 190 to 270°C, further preferably 200 to 260°C, even more preferably 220 to 250°C, and still more preferably 230 to 250°C. When the temperature of the heat treatment exceeds the upper limit value, coloring occurs due to thermal decomposition. On the other hand, when the temperature of the heat treatment is lower than the above lower limit value, sufficient adhesiveness is not exhibited.

[0080] The heat treatment time is preferably 0.1 to 50 seconds, more preferably 1 to 45 seconds, still more preferably 2 to 40 seconds, even more preferably 3 to 35 seconds, even more preferably 3 to 20 seconds, and even more preferably 3 to 10 seconds. When the heat treatment time exceeds the upper limit value, coloring occurs due to thermal decomposition. On the other hand, when the time is below the above lower limit, there is a risk of reduced adhesiveness.

[0081] It should be noted that when the heat treatment time is set to a short time of 30 seconds or less, it is also possible to perform the treatment in an online manner using a heat treatment furnace in the manufacturing process of polyvinyl alcohol fibers.

[0082] In the production of surface-modified fibers, the above heat treatment may be carried out only once, or may be carried out two or more times by changing the treatment temperature and treatment time. Among them, if multiple heat treatments are carried out at a high temperature, the surface-modified layer may decompose, resulting in coloring and reduced adhesive strength.

[0083] <Physical properties of surface-modified fibers>

[0084] In the present invention, the surface-modified fibers can be used in various shapes according to the use. For example, they can be short fibers such as cut fibers, or long fibers. In the case of long fibers, multifilaments are also a preferred form.

[0085] The strength of the surface-modified fibers is preferably 4 to 30 cN / dtex, and more preferably 5 cN / dtex or more.

[0086] It should be noted that the strength of the surface-modified fibers in the present invention can be measured by the method described in the examples.

[0087] The surface-modified fibers of the present invention can be used in any shape, and are preferably used in the form of fiber cords, fabrics, knitted fabrics, etc. that contain at least a part of the surface-modified fibers, and more preferably in the form of fabrics or knitted fabrics that contain at least a part of the surface-modified fibers. For example, they can be used in the form of surface-modified fibers embedded in resins, cements, etc. as described later.

[0088] [Molded body]

[0089] The molded article of the present invention is not particularly limited as long as the above surface-modified fibers are used. From the viewpoint of excellent adhesion between the above surface-modified fibers and the resin, a molded article having the above surface-modified fibers and a resin layer is preferred. From the viewpoint of maintaining the form of the resin, the surface-modified fibers used in the above molded article are preferably used in the form of a fabric or knitted fabric containing the surface-modified fibers in at least a part, and more preferably used as a part of a laminate formed by laminating a reinforcing layer formed by the fabric or knitted fabric and a resin layer.

[0090] The resin used in the molded article of the present invention is not particularly limited, and examples thereof include: polyolefin resins such as polyethylene resin, polypropylene resin, and polybutene resin; methacrylic resins such as polymethyl methacrylate resin; polystyrene resins such as polystyrene resin, ABS resin, and AS resin; polyester resins such as polyethylene terephthalate (PET) resin, polybutylene terephthalate (PBT) resin, polypropylene terephthalate resin, polyethylene naphthalate (PEN) resin, and poly(1,4-cyclohexanedimethylene terephthalate) (PCT) resin; polyamide (PA) resins such as 6-nylon resin, 6,6-nylon resin, and PA9T; polyvinyl chloride resin, polyoxymethylene (POM) resin, polycarbonate (PC) resin, polyphenylene sulfide (PPS) resin, modified polyphenylene ether (PPE) resin, polyetherimide (PEI) resin, polysulfone (PSF) resin, polyethersulfone (PES) resin, polyketone resin, polyarylate (PAR) resin, polyether nitrile (PEN) resin, polyether ketone (PEK) resin, polyether ether ketone (PEEK) resin, polyether ketone ketone (PEKK) resin, polyimide (PI) resin, polyamideimide (PAI) resin, fluorine (F) resin; liquid crystal polymer resins such as liquid crystal polyester resin; thermoplastic elastomers such as polystyrene, polyolefin, polyurethane, polyester, polyamide, polybutadiene, polyisoprene, or fluorine; or copolymer resins, modified resins, etc. thereof. These resins may be used alone or in combination of two or more.

[0091] Among them, polyvinyl chloride resin is preferred from the viewpoint of improving the adhesion to the surface-modified fibers.

[0092] The molded article of the present invention may be a fiber-reinforced resin in which the above surface-modified fibers are mixed in the resin. The resin used for the fiber-reinforced resin may also be appropriately the above resin.

[0093] When the molded article of the present invention is a fiber-reinforced resin, the content of the surface-modified fiber is preferably 0.1 to 50 parts by mass, more preferably 1 to 30 parts by mass, based on 100 parts by mass of the resin. When the blending amount of the surface-modified fiber relative to the resin is within the above range, the dispersibility of the surface-modified fiber in the resin becomes good, and an excellent reinforcing effect can be exhibited.

[0094] The method for making the above resin contain the surface-modified fiber of the present invention is not particularly limited, and examples thereof include a method of adding the surface-modified fiber to the particles of the above resin and uniformly mixing them. In addition, the manufacturing method of the fiber-reinforced resin is not particularly limited, and molding methods such as melt extrusion molding and injection molding can be adopted.

[0095] The resin used for the molded article of the present invention may contain additives such as impact resistance improvers and inorganic fillers. Examples of the additives include: flame retardants, conductivity imparting agents, crystal nucleating agents, ultraviolet absorbers, antioxidants, vibration damping materials, antibacterial agents, insect repellents, deodorants, anti-coloring agents, heat stabilizers, mold release agents, antistatic agents, lubricants, coloring agents, and foaming agents.

[0096] When using the above additives, the content thereof is preferably 10 parts by mass or less, more preferably 5 parts by mass or less, based on 100 parts by mass of the above resin. When the content of the additive is within the above range, the effect brought by the additive can be obtained while maintaining the reinforcing effect brought by the surface-modified fiber.

[0097] Examples

[0098] Hereinafter, the present invention will be described more specifically by way of examples and the like, but the present invention is not limited by any of these examples and the like.

[0099] <Fiber>

[0100] · Polyvinyl alcohol fiber (PVA)

[0101] Manufactured by Kuraray Co., Ltd., KURALON 5501 (2000 dtex, 1000 f)

[0102] · Polyamide fiber (PA)

[0103] Fiber obtained by melt spinning nylon 6 (1400 dtex, 204 f)

[0104] <Compound having a hydrogen bonding functional group>

[0105] [Polyethyleneimine (PEI)]

[0106] · Polyethyleneimine (1)

[0107] Nippon Shokubai Co., Ltd. "EPOMIN P-3000"

[0108] · Polyethyleneimine (2)

[0109] Nippon Shokubai Co., Ltd. "EPOMIN SP-200"

[0110] 〔Polyvinylpyrrolidone (PVP)〕

[0111] Nippon Shokubai Co., Ltd. "Polyvinyl pyrrolidone K-85"

[0112] 〔Polyallylamine〕

[0113] Nittobo Medical Co., Ltd. "PAA-15"

[0114] <Method for Preparing Solution Containing Compound with Hydrogen Bonding Functional Group>

[0115] The solution used in Example 1 was prepared by mixing 14.3 g of polyethyleneimine (1) and 985.7 g of water. In other Examples and Comparative Examples, the aqueous solution constituting the surface modification layer was prepared in the same manner using the compounds described in Table 1.

[0116] <Example 1>

[0117] After impregnating polyvinyl alcohol fibers (PVA fibers) in an aqueous solution containing a compound with a hydrogen bonding functional group, the liquid was squeezed with a roller. The obtained fiber thread was dried at 140 °C for 30 seconds. Then, heat treatment was performed at 240 °C for 5 seconds and winding was carried out, thereby producing surface-modified fibers.

[0118] <Examples 2 to 7, Comparative Examples 1 to 2>

[0119] The manufacturing conditions and the conditions of heat treatment were changed to the conditions described in Table 1, and except for this, surface-modified fibers were produced by the same method as in Example 1.

[0120] For the fibers obtained in the Examples and Comparative Examples, evaluation was carried out according to the following method. The results are shown in Table 1.

[0121] <Evaluation Method>

[0122] 〔Parameter of Hue (YI)〕

[0123] For the obtained surface-modified fibers, the parameter (YI) of the hue was measured using a haze meter SH7000 (manufactured by Nippon Electric Ornament Co., Ltd.) in accordance with JIS Z8722:2009. It should be noted that the values of three parts of the surface-modified fibers were measured, and the arithmetic mean thereof was used as the parameter (YI) of the hue. The results are shown in Table 1.

[0124] 〔Strength〕

[0125] According to the test method of JIS L-1013:2010, the obtained surface-modified fibers were set to have a filament length of 20 cm, an initial load of 0.25 g / d, and a stretching speed of 50% / minute, and the strength was measured in air at 20°C. The arithmetic mean of the five measured values was used as the value of this evaluation. It should be noted that the fineness (dtex) of the fiber was obtained by the mass method.

[0126] 〔Interfacial shear stress〕

[0127] An evaluation resin was prepared by adding 1% by mass of a curing agent to an unsaturated polyester resin (manufactured by Nippon Paint Co., Ltd.) and stirring. The obtained evaluation resin was attached in a spherical shape so as to surround the obtained surface-modified fibers, and left at room temperature (20°C) for 2 hours. Then, heat treatment was performed at 70°C for 2 hours.

[0128] After measuring the fiber diameter and the axial length (resin diameter) of the obtained specimen, it was fixed to a mounting paper, and the adhesive force was measured by a testing machine (INSTRON Corporation "Universal Testing Machine 3365"), and the interfacial shear stress was calculated by the following formula.

[0129] Interfacial shear stress (N / mm 2 ) = maximum detected load (N) / (π × fiber diameter (mm) × axial length (mm))

[0130] 〔Process passability〕

[0131] In each of the examples and comparative examples, an aqueous solution containing a compound having a hydrogen-bonding functional group was attached to each fiber. After winding up 5 kg of the surface-modified fibers, the degree of contamination (gumming up) of the holding roll after passing the surface-modified fibers was determined according to the following evaluation criteria.

[0132] · Criteria

[0133] G (good): There is no roll contamination caused by gumming, or the contamination is small, and there is no problem in the silk-making operability.

[0134] B (bad): The roll contamination caused by gumming is obvious, and single filaments fall off and entangle during silk-making, and there are problems in the silk-making operability.

[0135]

[0136] <Examples 8 and 9>

[0137] Compounds having a hydrogen-bonding functional group described in Table 2 were used, and surface-modified fibers were produced in the same manner as in Example 1, except for this. Next, the obtained surface-modified fibers were twisted at 120 turns / m and arranged at 36 fibers / inch to produce a curtain-like sample. The sample and a soft polyvinyl chloride resin sheet were overlapped and heated at 1 MPa pressure and 160 °C for 10 minutes to obtain a test piece. The obtained test piece was adjusted to a width of 1 inch, and the peel strength (N / inch) was measured using a measuring machine (INSTRON Corporation's "Universal Material Testing Machine 3365"). The results are shown in Table 2. The measurement results indicate that the larger the value, the greater the adhesive force between the surface-modified fiber and the polyvinyl chloride resin.

[0138] <Comparative Example 3>

[0139] No surface modification treatment was performed, and a sample was produced in the same manner as in Example 8, except for this, and the peel strength was measured. The results are shown in Table 2.

[0140]

[0141] From the results of the examples and comparative examples, it was clarified that according to the present invention, surface-modified fibers having excellent adhesiveness and capable of suppressing coloring can be obtained.

Claims

1. A surface-modified fiber having a fiber and a surface-modified layer covering at least a part of the surface of the fiber. The surface-modified layer contains a compound having a hydrogen-bonding functional group, and the amount of the surface-modified layer is 0.01 to 2.5 parts by mass with respect to 100 parts by mass of the fiber used as a raw material.

2. The surface-modified fiber according to claim 1, wherein the hydrogen-bonding functional group is at least one selected from the group consisting of a hydroxyl group, a carboxyl group, a carboxylate group, an esterified product of a carboxyl group, a carboxylic anhydride group, a carbonyl group, an aldehyde group, an acetalized product of an aldehyde group, an amino group, and an amide group.

3. The surface-modified fiber according to claim 1 or 2, wherein the fiber is at least one fiber selected from the group consisting of polyamide fibers, polyvinyl alcohol fibers, polyester fibers, and regenerated cellulose fibers.

4. The surface-modified fiber according to any one of claims 1 to 3, wherein the parameter (YI) of the hue of the surface-modified fiber is 0 to 50.

5. A method for producing a surface-modified fiber, which is a method for producing the surface-modified fiber according to any one of claims 1 to 4, and the method has the following steps (1) and (2): [Step (1)] A step of preparing a solution or dispersion of the compound having a hydrogen-bonding functional group and attaching the solution or dispersion to the fiber. [Step (2)] A step of heat-treating the fiber to which the solution or dispersion is attached under the conditions of 180 to 280 °C for 50 seconds or less.

6. A molded article using the surface-modified fiber according to any one of claims 1 to 4.

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