Resin composition, synthetic fiber, and method for producing the same

Abstract

The present invention provides a resin composition that can be dyed with dyes containing acidic dyes, and that prevents fiber adhesion after dyeing, thereby enabling the production of synthetic fibers. [Solution] The resin composition is a cationic polymer in which, when the total mass of polymer (A), polymer (B), and polymer (C) is 100% by mass, (A) is 70-94.9% by mass, (B) is 5-29.9% by mass, and (C) is 0.1-4% by mass, (A) contains 35% by mass or more of constituent units derived from acrylonitrile and has a glass transition temperature of 80-110°C, (B) contains 45% by mass or more of constituent units derived from one or more monomers selected from (meth)acrylic acid ester monomers and vinyl carboxylate ester monomers, (B) is water-insoluble and has a glass transition temperature of 20°C or more and less than 80°C, and (C) contains more than 65% by mass of constituent units derived from monomers containing one or more functional groups selected from amino groups and quaternary ammonium groups.

Description

Technical Field

[0001] The present invention relates to a resin composition that can be easily dyed with an acid dye, a synthetic fiber containing the same, and a method for producing the synthetic fiber.

Background Art

[0002] Modacrylic fibers using a modacrylic polymer containing acrylonitrile and one or more monomers selected from the group consisting of vinyl halides and vinylidene halides are excellent in touch and texture, and are widely used as synthetic fibers for artificial hair. On the other hand, conventionally, fibers for artificial hair have generally been in the form that consumers use fiber products dyed in a predetermined color at fiber manufacturers or processing factories as they are in the ready-made color. However, in recent years, consumers' color preferences have diversified, and fibers for artificial hair having various colors are in demand. Among them, fibers for artificial hair that can be easily dyed by consumers themselves with a commercially available hair dye for human hair containing an acid dye are in demand. For example, Patent Document 1 describes that a synthetic fiber containing a resin composition in which a polymer dissolved in benzyl alcohol is added to a modacrylic polymer can be easily dyed with a hair dye for human hair containing an acid dye.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, the synthetic fiber containing the resin composition described in Patent Document 1 has a problem that fiber adhesion occurs after dyeing, more specifically, after washing with warm water after dyeing.

[0005] To solve the above-mentioned conventional problems, the present invention relates to a resin composition that can be dyed with a dyeing agent containing an acid dye and that prevents fiber adhesion that may occur after dyeing, a synthetic fiber containing the same, and a method for producing a synthetic fiber. [Means for solving the problem]

[0006] One or more embodiments of the present invention are resin compositions comprising polymer (A), polymer (B), and polymer (C), wherein polymer (A) contains 35% by mass or more of structural units derived from acrylonitrile, polymer (A) has a glass transition temperature of 80 to 110°C, polymer (B) contains 45% by mass or more of structural units derived from one or more monomers (b) selected from the group consisting of (meth)acrylic acid ester monomers and vinyl carboxylate ester monomers, polymer (B) is water-insoluble and has a glass transition temperature The present invention relates to a resin composition having a temperature of 20°C or higher and less than 80°C, wherein polymer (C) is a cationic polymer containing more than 65% by mass of constituent units derived from monomer (c) containing one or more functional groups selected from the group consisting of amino groups and quaternary ammonium groups, and the total mass of polymer (A), polymer (B), and polymer (C) is 100% by mass, with polymer (A) content being 70-94.9% by mass, polymer (B) content being 5-29.9% by mass, and polymer (C) content being 0.1-4% by mass.

[0007] One or more embodiments of the present invention relate to synthetic fibers containing the resin composition.

[0008] One or more embodiments of the present invention relate to a method for producing synthetic fibers, which includes a step of melt-spinning the resin composition. [Effects of the Invention]

[0009] According to one or more embodiments of the present invention, it is possible to provide a resin composition that can be dyed with a dyeing agent containing an acid dye, and that prevents fiber adhesion after dyeing. Furthermore, according to one or more embodiments of the present invention, it is possible to provide a synthetic fiber that can be dyed with a dyeing agent containing an acid dye, and that prevents fiber adhesion after dyeing. Furthermore, according to the manufacturing method of one or more embodiments of the present invention, synthetic fibers can be obtained that can be dyed with a dyeing agent containing an acid dye, and in which fiber adhesion after dyeing is prevented. [Modes for carrying out the invention]

[0010] The inventors of the present invention have conducted extensive research to obtain synthetic fibers that improve dyeability with dyes containing acid dyes and prevent fiber adhesion after dyeing. As a result, they found that by (1) creating a resin composition using polymer (A) containing 35% by mass or more of acrylonitrile-derived structural units with a glass transition temperature within a predetermined range, polymer (B) containing 45% by mass or more of structural units derived from one or more monomers (b) selected from the group consisting of (meth)acrylic acid ester monomers and vinyl carboxylate ester monomers, and polymer (C) which is a cationic polymer containing more than 65% by mass of structural units derived from monomer (c) containing an amino group and / or a quaternary ammonium group, and (2) using polymer (B) that is water-insoluble and has a glass transition temperature within a predetermined range, and (3) blending polymer (A), polymer (B), and polymer (C) in a predetermined proportion, the dyeability of synthetic fibers containing the resin composition with dyes containing acid dyes is improved, and fiber adhesion after dyeing is prevented.

[0011] In this specification, when a numerical range is indicated by "~", the numerical range includes both endpoints (upper and lower limits). For example, the numerical range "X~Y" includes both endpoints X and Y, and is the same as the range "X or greater and Y or less". Furthermore, any number within that range or any range included within that range is specifically disclosed. In addition, when multiple numerical ranges are described in this specification, they shall include numerical ranges that are appropriately combined from the upper and lower limits of different numerical ranges.

[0012] <Polymer (A)> Polymer (A) contains 35% by mass or more of constituent units derived from acrylonitrile. Polymer (A) has a glass transition temperature of 80 to 110°C. A glass transition temperature of 80°C or higher of polymer (A) results in good heat resistance of the fibers. A glass transition temperature of 110°C or lower of polymer (A) results in good melt processability. The glass transition temperature of polymer (A) is preferably 80 to 105°C, more preferably 80 to 100°C, and even more preferably 80 to 95°C. In this specification, the glass transition temperature of the polymer can be measured as described in the examples.

[0013] Polymer (A) may contain other constituent units in addition to 35% by mass or more of constituent units derived from acrylonitrile, provided that the glass transition temperature is within the range described above. From the viewpoint of flame retardancy, it is preferable that the other constituent units include constituent units derived from one or more halogen-containing monomers (a1) selected from the group consisting of vinyl halides and vinylidene halides. From the viewpoint of melt processability, it is preferable that the other constituent units include constituent units derived from macromonomers (a2) having a polymer of ethylenically unsaturated monomer (d) as the main chain.

[0014] The polymer (A) is preferably a modacrylic resin containing 35-84% by mass of structural units derived from acrylonitrile, 15-64% by mass of structural units derived from the halogen-containing monomer (a1), and 1-30% by mass of structural units derived from the macromonomer (a2); preferably a modacrylic resin containing 40-80% by mass of structural units derived from acrylonitrile, 19-59% by mass of structural units derived from the halogen-containing monomer (a1), and 1-20% by mass of structural units derived from the macromonomer (a2); and preferably a modacrylic resin containing 40-75% by mass of structural units derived from acrylonitrile, 24-59% by mass of structural units derived from the halogen-containing monomer (a1), and 1-15% by mass of structural units derived from the macromonomer (a2). This makes it possible to obtain a synthetic fiber that has good melt processability, excellent feel and texture, and is suitable for use in artificial hair.

[0015] Examples of the aforementioned vinyl halogens include vinyl chloride, vinyl bromide, and vinyl iodide. Examples of the aforementioned vinylidenes include vinylidene chloride, vinylidene bromide, and vinylidene iodide. These may be used individually or in combination of two or more. From the viewpoint of heat resistance, the halogen-containing monomer (a1) is preferably vinyl chloride and / or vinylidene chloride, and more preferably vinyl chloride.

[0016] Generally, a macromonomer refers to an oligomer molecule having a reactive functional group at the end of the polymer. The macromonomer (a2) has a polymer consisting of an ethylenically unsaturated monomer (d) as its main chain. The ethylenically unsaturated monomer (d) is not particularly restricted, and various types can be used. Examples include (meth)acrylic acid ester monomers, styrene monomers, nitrile group-containing vinyl monomers, amide group-containing vinyl monomers, fluorine-containing vinyl monomers, silicon-containing vinyl monomers, maleimide monomers, vinyl esters, alkenes, and conjugated dienes. In addition, maleic anhydride, maleic acid, monoalkyl and dialkyl esters of maleic acid; fumaric acid, monoalkyl and dialkyl esters of fumaric acid; allyl chloride, and allyl alcohol can also be used. In this specification, (meth)acrylic acid means acrylic acid and / or methacrylic acid.

[0017] Examples of the (meth)acrylic acid ester monomers include (meth)acrylic acid aliphatic hydrocarbons (e.g., alkyl groups with 1 to 18 carbon atoms) esters, (meth)acrylic acid alicyclic hydrocarbon esters, (meth)acrylic acid aromatic hydrocarbon esters, and (meth)acrylic acid aralkyl esters. Examples of the (meth)acrylic acid aliphatic hydrocarbon esters include (meth)acrylate, (meth)acrylate, n-butyl (meth)acrylate, tert-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, dodecyl (meth)acrylate, and stearyl (meth)acrylate. Examples of the (meth)acrylic acid alicyclic hydrocarbon esters include (meth)acrylate cyclohexyl and (meth)acrylate isobornyl. Examples of the (meth)acrylic acid aromatic hydrocarbon esters include (meth)acrylate phenyl and (meth)acrylate toluyl. Examples of the (meth)acrylic acid aralkyl esters include (meth)acrylate benzyl.

[0018] As the (meth)acrylic acid ester monomer, for example, a (meth)acrylic acid ester monomer having a heteroatom in the ester portion may be used. The heteroatom is not particularly limited and examples include oxygen (O), fluorine (F), nitrogen (N), etc. Specific examples of the (meth)acrylic acid ester monomer having a heteroatom in the ester portion include 2-methoxyethyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, glycidyl (meth)acrylate, 2-aminoethyl (meth)acrylate, 2-dimethylaminoethyl (meth)acrylate, 2-trifluoromethyl (meth)acrylate, 2,2,2-trifluoroethyl (meth)acrylate, and 2-(perfluorobutyl)ethyl (meth)acrylate.

[0019] Examples of the styrene-based monomers include styrene, vinyltoluene, α-methylstyrene, chlorostyrene, styrenesulfonic acid, and their salts.

[0020] Examples of the nitrile group-containing vinyl monomers include acrylonitrile and methacrylonitrile.

[0021] Examples of the amide group-containing vinyl monomers include acrylamide and methacrylamide.

[0022] Examples of the fluorine-containing vinyl monomer include perfluoroethylene, perfluoropropylene, vinylidene fluoride, etc. Examples of the silicon-containing vinyl monomer include vinyltrimethoxysilane, vinyltriethoxysilane, etc. Examples of the maleimide monomer include maleimide, methylmaleimide, butylmaleimide, stearylmaleimide, phenylmaleimide, cyclohexylmaleimide, etc. Examples of the vinyl esters include vinyl acetate, vinyl propionate, vinyl pivalate, vinyl benzoate, vinyl cinnamate, etc. Examples of the alkenes include ethylene, propylene, etc. Examples of the conjugated dienes include butadiene, isoprene, etc.

[0023] The ethylenically unsaturated monomer may be used alone or two or more thereof may be copolymerized. From the viewpoint of melt processability, the ethylenically unsaturated monomer (d) is preferably at least one selected from the group consisting of (meth)acrylate monomers, styrene monomers, nitrile group-containing vinyl monomers, and amide group-containing vinyl monomers. More preferably, it is at least one selected from the group consisting of (meth)acrylate monomers and nitrile group-containing vinyl monomers, and still more preferably, it is at least one selected from the group consisting of acrylate monomers and nitrile group-containing vinyl monomers. The ethylenically unsaturated monomer may be used alone or two or more thereof may be copolymerized.

[0024] The macro monomer (a2) preferably has at least one reactive functional group (also referred to as a polymerizable functional group) at one molecular end per molecule, and more preferably has at least one reactive functional group at one molecular fragment end per molecule. Examples of the reactive functional group (also referred to as a polymerizable functional group) include an allyl group, a vinylsilyl group, a vinyl ether group, a dicyclopentadienyl group, and a functional group having a polymerizable carbon-carbon double bond represented by the following general formula (1). The macro monomer (a2) can usually be produced by radical polymerization. In particular, since the reactivity with halogen-containing monomers such as acrylonitrile and vinyl chloride is good, in the macro monomer, the reactive functional group is preferably a functional group having a polymerizable carbon-carbon double bond represented by the following general formula (1).

[0025] CH2=C(R)―C(O)O― (1) In the general formula (1), R represents hydrogen or an organic group having 1 to 20 carbon atoms. The organic group may be an alkyl group, an aryl group, etc., and specifically, a substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, a phenyl group, etc. may be used. Specific examples of R are not particularly limited. For example, functional groups selected from the group consisting of -H, -CH3, -CH2CH3, -(CH2) n CH3 (n represents an integer of 2 to 19), -C6H5, -CH2OH, and -CN are preferred, and more preferably functional groups selected from the group consisting of -H and -CH3. Specifically, a one-terminal acryloyl group poly(2-methoxyethyl acrylate) macro monomer etc. may be used.

[0026] The production method of the macro monomer (a2) is not particularly limited, and a conventionally known production method can be used. For example, Japanese Patent Application Laid-Open No. 2006-299240 describes a detailed production method of the macro monomer used in one or more embodiments of the present invention, and any of these production methods may be used, but usually, a controlled radical polymerization method is utilized, and from the viewpoint of ease of control etc., a living radical polymerization method is preferably used, and an atom transfer radical polymerization method is particularly preferred.

[0027] The mass-average molecular weight (Mw) of polymer (A) is preferably 10,000 to 300,000, and more preferably 30,000 to 150,000, from the viewpoint of melt processability and fibrous properties.

[0028] The method for producing polymer (A) is not particularly limited, but copolymerization in an aqueous medium is preferred, for example, because of the ease of polymerization control and the ease of separation and washing of polymer particles after polymerization. Examples of polymerization methods in an aqueous medium include suspension polymerization, microsuspension polymerization, and emulsion polymerization. Among these, suspension polymerization or microsuspension polymerization is preferred from the viewpoint of polymerization stability, and suspension polymerization is even more preferred.

[0029] In suspension polymerization or microsuspension polymerization, the monomers mentioned above, along with suspension dispersants, polymerization initiators, and chain transfer agents, can be charged together, in portions, or continuously as needed, and the copolymerization reaction can be carried out at a predetermined polymerization temperature, for example, 25 to 100°C.

[0030] Examples of the suspension dispersant include partially saponified polyvinyl acetate; water-soluble cellulose ethers such as methylcellulose, hydroxyethylcellulose, hydroxypropylcellulose, hydroxypropylmethylcellulose, and carboxymethylcellulose; polyethylene oxide; polyvinylpyrrolidone; polyacrylic acid; vinyl acetate-maleic acid copolymer; styrene-maleic acid copolymer; gelatin; and organic polymer dispersants such as starch. These may be used individually or in combination of two or more.

[0031] The polymerization initiator is not particularly limited, but it is preferable to use an oil-soluble polymerization initiator with a 10-hour half-life temperature of 30 to 65°C. Examples of such oil-soluble polymerization initiators include organic peroxide-based polymerization initiators such as diisobutyl peroxide, cumyl peroxyneodecanoate, diisopropyl peroxydicarbonate, di(2-ethylhexyl) peroxydicarbonate, t-butyl peroxypivalate, t-butyl peroxyneodecanoate, 1,1,3,3-tetramethylbutyl peroxyneodecanoate, dilauroyl peroxide, and di(3,5,5-trimethylhexanoyl) peroxide. These oil-soluble polymerization initiators may be used individually or in combination of two or more.

[0032] The chain transfer agent is not particularly limited, but it is preferable to use a thiol-based chain transfer agent. Examples of such thiol-based chain transfer agents include ethanethiol, 1-propanethiol, 1-butanethiol, 1-octanthiol, 1-decanethiol, 1-dodecanethiol, 1-hexadecanethiol, 1-octadecanethiol, cyclohexanethiol, benzenethiol, allyl mercaptan, 2-mercaptoethanol, α-thioglycerol, thioglycolic acid, methyl thioglycolate, ethyl thioglycolate, 2-aminoethanethiol, sodium 2-mercaptoethanesulfonate, 4-nitrobenzenethiol, and cysteine.

[0033] During polymerization, surfactants, dispersants, antioxidants, degree of polymerization regulators, particle size regulators, pH regulators, gelling modifiers, antistatic agents, stabilizers, and scale inhibitors may be used as needed.

[0034] In suspension polymerization or microsuspension polymerization, polymer (A), such as modacrylic resin, is obtained in latex or slurry form. There are no particular restrictions on the method of drying this to obtain a copolymer resin in powder or granular form. Examples include dewatering the latex or slurry and then drying it by static drying in a hot air dryer or the like.

[0035] <Polymer (B)> Polymer (B) contains 45% by mass or more of constituent units derived from one or more monomers (b) selected from the group consisting of (meth)acrylic acid ester monomers and vinyl carboxylate ester monomers, preferably 50% by mass or more, more preferably 60% by mass or more, even more preferably 70% by mass or more, even more preferably 80% by mass or more, even more preferably 90% by mass or more, and may also consist of 100% by mass. As a result, polymer (B) is readily soluble in alcohol, particularly benzyl alcohol, and therefore acid dyes easily penetrate into the synthetic fibers obtained by melt-spunting the resin composition, improving dyeability.

[0036] The (meth)acrylic acid ester monomers are not particularly limited, and the (meth)acrylic acid ester monomers described in the section on macromonomers above can be used, and the details therein will be referenced, so a specific explanation will be omitted here. From the viewpoint of improving the dyeability of fibers, the (meth)acrylic acid ester monomers are preferably methyl (meth)acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate, tert-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, cyclohexyl (meth)acrylate, phenyl (meth)acrylate, benzyl (meth)acrylate, 2-methoxyethyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, and glycidyl (meth)acrylate.

[0037] The vinyl carboxylate monomer may be a fatty acid vinyl ester monomer or an aromatic vinyl carboxylate monomer.

[0038] In the fatty acid vinyl ester monomer, the number of carbon atoms in the fatty acid is not particularly limited and may be, for example, 1 to 20 or 2 to 15. Specific examples of the fatty acid vinyl ester monomer include saturated fatty acid vinyl esters such as vinyl acetate, vinyl propionate, vinyl butyrate, vinyl pivalate, vinyl caproate, vinyl caprylate, vinyl caprate, vinyl laurate, vinyl palmitate, and vinyl stearate. From the viewpoint of reactivity with other monomers, the number of carbon atoms in the fatty acid is preferably 2 to 5.

[0039] In the aforementioned aromatic carboxylic acid vinyl ester monomer, the number of carbon atoms in the aromatic carboxylic acid is not particularly limited, but may be, for example, 7 to 9. Specific examples of the aromatic carboxylic acid vinyl ester monomer include vinyl benzoate and vinyl cinnamate.

[0040] Polymer (B) may contain structural units derived from other monomers in addition to structural units derived from monomer (b). The other monomers are not particularly limited, as long as they are copolymerizable with monomer (b), but examples include styrene monomers, nitrile group-containing vinyl monomers, amide group-containing vinyl monomers, and (meth)acrylic acid.

[0041] Polymer (B) is water-insoluble. As a result, in synthetic fibers obtained by melt-spinning a resin composition containing polymer (B), polymer (B) does not dissolve onto the surface of the synthetic fibers after dyeing, and therefore fiber adhesion is suppressed. In this specification, "water-soluble" means that when 0.1 g of polymer is mixed with 5 mL of water and stirred at room temperature (20 ± 5 °C) for 2 hours, a uniform and transparent solution is obtained without any visible turbidity or other solid content.

[0042] Polymer (B) is preferably soluble in alcohol, particularly benzyl alcohol. In this specification, "soluble in benzyl alcohol" means that when 0.1 g of polymer is added to 5 mL of benzyl alcohol and stirred at room temperature (20 ± 5 °C) for 2 hours, a uniform and transparent solution is obtained without any visible turbidity or other solid content.

[0043] Polymer (B) has a glass transition temperature of 20°C or higher and less than 80°C. If the glass transition temperature of polymer (B) is 20°C or higher, the melt processability of the resin composition containing polymer (B) will be good. If the glass transition temperature of polymer (B) is less than 80°C, the dyeability of the fibers will be good.

[0044] From the viewpoint of being insoluble in water and having a glass transition temperature that easily satisfies the above-mentioned range, polymer (B) is preferably a polymer containing 45% or more by mass, 50% or more by mass, 60% or more by mass, 70% or more by mass, 80% or more by mass, or 90% or more by mass of one or more constituent units from the group consisting of constituent units derived from monomer (b), such as glycidyl group-containing (meth)acrylic acid esters such as glycidyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, cyclohexyl (meth)acrylate, and benzyl (meth)acrylate, and preferably a homopolymer consisting of 100% by mass. Polymer (B) more preferably contains 45% or more by mass, 50% or more by mass, 60% or more by mass, 70% or more by mass, 80% or more by mass, or 90% or more by mass of constituent units derived from glycidyl group-containing (meth)acrylic acid esters such as glycidyl (meth)acrylate, and is particularly preferably a homopolymer consisting of 100% by mass (i.e., poly(glycidyl group-containing (meth)acrylic acid ester)).

[0045] The mass-average molecular weight (Mw) of polymer (B) is preferably 5,000 to 300,000, and more preferably 10,000 to 200,000, from the viewpoint of dyeability and melt processability.

[0046] <Polymer (C)> Polymer (C) is a cationic polymer containing more than 65% by mass of constituent units derived from monomer (c) which contains one or more functional groups selected from the group consisting of amino groups and quaternary ammonium groups. By using such polymer (C) in combination with polymer (B), polymer (C) ionically bonds with the acid dye that has penetrated by polymer (B) in a synthetic fiber mainly composed of polymer (A), making it easier for the acid dye to adhere to the fiber, and therefore improving dyeability.

[0047] The monomer (c) is not particularly limited, but examples include diallyl dialkylammonium salts, amino group-containing (meth)acrylic acid esters, and quaternary ammonium group-containing (meth)acrylic acid esters.

[0048] Examples of the diallyldialkylammonium salt include diallyldialkylammonium halides, diallyldialkylammonium sulfates, and diallyldialkylammonium phosphates. Examples of the diallyldialkylammonium halides include diallyldimethylammonium chloride and diallyldimethylammonium fluoride.

[0049] Examples of the amino group-containing (meth)acrylic acid esters include dimethylaminomethyl (meth)acrylate, diethylaminomethyl (meth)acrylate, dimethylaminoethyl (meth)acrylate, and diethylaminoethyl (meth)acrylate.

[0050] Examples of the quaternary ammonium group-containing (meth)acrylic acid esters include trimethylammonium ethyl (meth)acrylate chloride, trimethylammonium ethyl (meth)acrylate bromide, and trimethylammonium ethyl (meth)acrylamide chloride.

[0051] From the viewpoint of improving the dyeability of the fibers, the monomer (c) is preferably a diallyldialkylammonium halide, and more preferably a diallyldialkylammonium chloride.

[0052] The polymer (C) may contain structural units derived from monomer (c) containing one or more functional groups selected from the group consisting of amino groups and quaternary ammonium groups, as well as structural units derived from other monomers. The other monomers are not particularly limited, as long as they are copolymerizable with monomer (c), but examples include (meth)acrylamide and (meth)acrylic acid ester monomers.

[0053] Polymer (C) is preferably a polymer containing more than 65% by mass, 70% or more by mass, 80% or more by mass, or 90% or more by mass of structural units derived from monomer (c), and is preferably a homopolymer consisting of 100% by mass (i.e., poly(diallyldialkylammonium salt)). Polymer (C) is preferably a polymer containing more than 65% by mass, 70% or more by mass, 80% or more by mass, or 90% or more by mass of structural units derived from diallyldialkylammonium halide, and is more preferably a homopolymer consisting of 100% by mass (i.e., poly(diallyldialkylammonium halide)). Polymer (C) is even more preferably a polymer containing more than 65% by mass, 70% or more by mass, 80% or more by mass, or 90% or more by mass of structural units derived from diallyldialkylammonium chloride, and is preferably a homopolymer consisting of 100% by mass (i.e., poly(diallyldialkylammonium chloride)).

[0054] <Resin composition> In one or more embodiments of the present invention, the resin composition comprises polymer (A), polymer (B), and polymer (C), and when the total mass of polymer (A), polymer (B), and polymer (C) is 100% by mass, it is preferable that the content of polymer (A) is 70-94.9% by mass, the content of polymer (B) is 5-29.9% by mass, and the content of polymer (C) is 0.1-4% by mass, or that the content of polymer (A) is 75-94.5% by mass, the content of polymer (B) is 5-24.5% by mass, and the content of polymer (C) is 0.5-3% by mass. By melt spinning such a resin composition, synthetic fibers can be obtained that can be dyed with dyes containing acid dyes, and that prevent fiber adhesion that may occur after dyeing.

[0055] The resin composition may contain, in addition to polymer (A), polymer (B), and polymer (C), other polymers, as long as they do not impair the objectives of the present invention. Examples of other polymers include polymers containing structural units derived from (meth)acrylic acid ester monomers. The amount of the other polymer may be 20 parts by mass or less, 10 parts by mass or less, or 5 parts by mass or less, when the total amount of polymer (A), polymer (B), and polymer (C) is 100 parts by mass.

[0056] The resin composition may contain a plasticizer (also simply referred to as a plasticizer) which is an organic compound that is compatible with polymer (A) and has a boiling point of 200°C or higher. In this specification, "compatible" means that when 10 mg of polymer and 2 g of an organic compound with a boiling point of 200°C or higher are placed in a 19 mL borosilicate glass tube, the glass tube is sealed with a silicone stopper, and the mixture is heated at 160°C for 30 minutes with occasional stirring, the polymer dissolves. In this specification, "boiling point" means the standard boiling point under atmospheric pressure (760 mmHg).

[0057] The plasticizer is not particularly limited, as long as it is an organic compound that is compatible with the polymer (A) and has a boiling point of 200°C or higher. For example, sulfone compounds such as dimethyl sulfone, diethyl sulfone, dipropyl sulfone, dibutyl sulfone, diphenyl sulfone, vinyl sulfone, ethylmethyl sulfone, methylphenyl sulfone, methylvinyl sulfone, and 3-methylsulfolane; sulfoxide compounds such as dipropyl sulfoxide, tetramethylene sulfoxide, diisopropyl sulfoxide, methylphenyl sulfoxide, dibutyl sulfoxide, diisobutyl sulfoxide, di-p-tolyl sulfoxide, diphenyl sulfoxide, and benzyl sulfoxide; lactides such as lactide lactide; lactams such as pyrrolidone, N-vinylpyrrolidone, ε-caprolactam, and N-methylcaprolactam; and lactones such as γ-butyrolactone, γ-hexalactone, γ-heptalactone, γ-octaractone, ε-caprolactone, and ε-octaractone can be used. The plasticizer may be used alone or in combination of two or more types.

[0058] The melting point of the plasticizer is preferably 60°C or higher, and more preferably 90°C or higher. For example, it is preferable to use one or more selected from the group consisting of dimethyl sulfone, lactide lactate, and ε-caprolactam, and it is more preferable to use one or more selected from the group consisting of dimethyl sulfone and lactide lactate.

[0059] From the viewpoint of melt processability, the resin composition preferably contains 0.1 to 50 parts by mass, 0.5 to 40 parts by mass, 1 to 30 parts by mass, or 2.5 to 20 parts by mass of the plasticizer per 100 parts by mass of the total amount of polymer (A), polymer (B), and polymer (C).

[0060] The resin composition may further contain a heat stabilizer for thermal stability. The heat stabilizer is not particularly limited as long as it provides thermal stability. From the viewpoint of improving melt processability, suppressing discoloration, and ensuring transparency, the heat stabilizer is preferably one or more selected from the group consisting of epoxy-based heat stabilizers, hydrotalcite-based heat stabilizers, tin-based heat stabilizers, Ca-Zn-based heat stabilizers, and β-diketone-based heat stabilizers. The heat stabilizer may be used alone or in combination of two or more.

[0061] From the viewpoint of color suppression effect and transparency, the aforementioned resin composition preferably contains 0.1 to 30 parts by mass, 0.2 to 20 parts by mass, or 0.5 to 10 parts by mass or less of the heat stabilizer per 100 parts by mass of the total amount of polymer (A), polymer (B), and polymer (C). A concentration of 0.1 parts by mass or more provides a good color suppression effect.

[0062] The resin composition may contain a lubricant, to the extent that it does not impair the objectives of the present invention, from the viewpoint of reducing friction with the processing machine, reducing heat generation due to shear, and improving fluidity and mold release properties. Examples of the lubricant include fatty acid ester lubricants, hydrocarbon lubricants, fatty acid lubricants, higher alcohol lubricants, aliphatic amide lubricants, alkylene fatty acid amide lubricants, and metal soap lubricants. The lubricant may be used alone or in combination of two or more types. The amount of lubricant added may be 10 parts by mass or less per 100 parts by mass of the total amount of polymer (A), polymer (B), and polymer (C).

[0063] The resin composition may contain processing aids from the viewpoint of improving spinnability. When the resin composition is used to form fibers, it is preferable to include a (meth)acrylate polymer and / or a styrene-acrylonitrile copolymer as processing aids. The processing aids may be used individually or in combination of two or more. The amount of processing aids added may be 10 parts by mass or less per 100 parts by mass of the total amount of polymer (A), polymer (B), and polymer (C).

[0064] The resin composition can be obtained, for example, by melt-kneading a powder mixture containing polymer (A), polymer (B), and polymer (C). First, polymer (A), polymer (B), and polymer (C), along with plasticizers, heat stabilizers, lubricants, processing aids, etc., as needed, are mixed to obtain a powder mixture. The mixing is not particularly limited, but for example, a Henschel mixer, a super mixer, and a ribbon blender can be used.

[0065] Next, the powder mixture is melt-kneaded. The kneading temperature is preferably, for example, 40 to 200°C, more preferably 80 to 185°C, and even more preferably 100 to 165°C. The kneading equipment is not particularly limited, but for example, a single-screw extruder, a twin-screw extruder, a plast mill, and a pressure kneader can be used. By melt-kneading the powder mixture, a lump-shaped or strand-shaped resin composition can be obtained. Alternatively, a pellet-shaped resin composition may be obtained by pelletizing the strand-shaped resin composition.

[0066] <Synthetic Fibers> The synthetic fiber comprises the resin composition. Specifically, the synthetic fiber can be obtained by melt spinning the resin composition (for example, a pelletized resin composition after melt kneading). First, the resin composition is melt-spun to form an undrawn fibrous yarn. Specifically, the melt-kneaded resin composition (pelletized resin composition) is discharged from a spinning nozzle attached to an extruder and taken up to form an undrawn yarn. The extruder may be any of the following: a single-screw extruder, a twin-screw extruder with different orientations, or a conical twin-screw extruder. In melt spinning, the cylinder temperature may be, for example, 120-200°C, 130-180°C, or 130-160°C, and the nozzle temperature may be, for example, 160-250°C, 165-245°C, or 170-245°C. The nozzle draft (ratio of take-up speed to discharge speed) may be 1-100 times, or 5-50 times. The cross-sectional shape of the holes in the spinning nozzle is not particularly limited and can be set appropriately according to the purpose and the cross-sectional shape of the synthetic fiber. The cross-sectional shape of the synthetic fiber and the spinning nozzle may be circular, for example, or other irregular shapes (e.g., elliptical, cocoon-shaped, etc.).

[0067] The undrawn yarn obtained above can be subjected to a drawing treatment by a known method, and, if necessary, a heat relaxation treatment. For example, when used as artificial hair, it is preferable to use a drawn yarn (multifilament) with a single fiber fineness of 2 to 100 dtex or 5 to 90 dtex. Drawing may be performed by dry drawing in a dry heat atmosphere at a drawing temperature of 70 to 150°C. The drawing ratio is preferably about 1.1 to 6 times, and more preferably about 1.5 to 4.5 times. The heat relaxation treatment can be performed in a dry heat atmosphere at 70 to 160°C. The relaxation rate may be, for example, 1 to 50% or 5 to 40%. In the present invention, the single fiber fineness is measured in accordance with JIS L 1013:2021.

[0068] The aforementioned synthetic fiber can be dyed with dyes containing acid dyes and alcohol, and is easily dyeable with acid dyes. Therefore, it can be dyed with general human hair dyes containing acid dyes and alcohol. Acid dyes refer to water-soluble dyes that have acidic groups such as sulfonic acid groups and carboxyl groups in their molecules. Since the aforementioned synthetic fiber contains polymer (B), it is presumed that polymer (B) swells due to the alcohol contained in the dye and the dye, especially benzyl alcohol, allowing the acid dye to penetrate into the interior of the synthetic fiber and enable dyeing. Furthermore, since the aforementioned synthetic fiber contains cationic polymer (C), it is presumed that polymer (C) ionically bonds with the acid dye, so even when washed with hot water after dyeing, the acid dye does not wash out of the synthetic fiber, improving dyeability.

[0069] The aforementioned acid dyes are not particularly limited and include, for example, Red No. 2, Red No. 102, Red No. 106, Red No. 201, Red No. 227, Yellow No. 4, Yellow No. 5, Yellow No. 203, Yellow No. 403, Yellow No. 406, Blue No. 1, Green No. 204, Orange No. 205, Purple No. 401, and Black No. 401.

[0070] The aforementioned alcohol is not particularly limited and includes, for example, ethanol, 1-propanol, 2-propanol, benzyl alcohol, 2-(benzyloxy)ethanol, 2-phenylethyl alcohol, cinnamic alcohol, phenylpropanol, phenoxyethanol, and α-methylbenzyl alcohol. Benzyl alcohol is particularly preferred.

[0071] Hair dyes for human hair are not particularly limited and can be used in various forms, including liquid, cream, gel, paste, and foam, and may be commercially available.

[0072] Dyes for human hair, etc., may optionally contain organic solvents other than alcohol, cationic polymers, surfactants, oily components such as silicone derivatives, thickeners such as hydroxypropyl methylcellulose, hydroxyethylcellulose, and xanthan gum, fragrances, preservatives, antioxidants, ultraviolet absorbers, chelating agents, propellants, and pearlescent agents.

[0073] The aforementioned synthetic fibers do not exhibit fiber adhesion even after dyeing. Normally, when artificial hair fibers are dyed, they are washed with warm water at 36-42°C after dyeing. At this time, water-soluble polymers tend to dissolve onto the surface of the synthetic fibers. However, since polymer (B) contained in the synthetic fibers is water-insoluble, it does not dissolve onto the surface of the synthetic fibers, and it is presumed that fiber adhesion does not occur after dyeing.

[0074] The aforementioned synthetic fiber has a good feel and excellent dyeability, particularly with dyes containing acidic dyes such as acidic dyes for human hair, making it suitable for use as artificial hair in headwear products. The aforementioned synthetic fiber may be used alone as artificial hair, or in combination with other artificial hair fibers.

[0075] The headwear product is not particularly limited, but preferably one selected from the group consisting of hair wigs, hairpieces, weaving, hair extensions, braided hair, hair accessories, and doll hair. Since the headwear product contains synthetic fibers that are easily dyed with acid dyes, it can be dyed to a desired color with a human hair dye containing an acid dye. [Examples]

[0076] The following describes one or more embodiments of the present invention in more detail with reference to examples. However, the present invention is not limited to the following embodiments.

[0077] First, we will explain the various measurement and evaluation methods.

[0078] (Glass transition temperature) Using a differential scanning calorimetry (DSC, manufactured by Seiko Instruments, model number "DSC-6100"), the temperature of a polymer sample (2 mg) was increased from 0°C to 160°C at a heating rate of 10°C / min under a nitrogen atmosphere. The differential value (DDSC) was determined from the DSC curve obtained, and the temperature at which the DDSC peaked was determined as the glass transition temperature of the polymer.

[0079] (molecular weight) The mass-average molecular weight and number-average molecular weight of macromonomers, or the mass-average molecular weight of polymer (A), were measured and calculated using GPC (Gel Permeation Chromatography) with a Tosoh Corporation "HLC-8320GPC" device. The molecular weight distribution of macromonomers was calculated based on the mass-average molecular weight and number-average molecular weight.

[0080] (Solubility in benzyl alcohol) 0.1 g of polymer (B) was mixed with 5 mL of benzyl alcohol, and the mixture was stirred at 700 rpm for 2 hours at room temperature (20 ± 5°C) using a stirrer (AS ONE Corporation, model number "RSH-4DR"). The dissolution of polymer (B) was then visually observed and evaluated.

[0081] (Solubility in water) 0.1 g of polymer (B) was mixed with 5 mL of water, and the mixture was stirred at 700 rpm for 2 hours at room temperature (20 ± 5 °C) using a stirrer (AS ONE Corporation, model number "RSH-4DR"). The dissolution of polymer (B) was then visually observed and evaluated.

[0082] (Dyeing treatment of fibers) The dyeability and adhesion of the fibers were evaluated by the following method. A human hair acid dye (manufactured by Ilya Chemical Co., Ltd., product name "Color Coat Decore D-1 (Natural Black)") was applied to the fiber bundles and left to stand at room temperature (20±5℃). After standing for 15 minutes, the bundles were rinsed with warm water at 38-40℃, washed with a 1.0% by mass sodium dodecyl sulfate aqueous solution (room temperature (20±5℃)) and warm water (38-40℃), and then allowed to stand and dry at room temperature. <Stainability> The dyeability of the fibers after dyeing treatment was evaluated visually using the following six-level criteria. 5: Extremely darkly stained 4: Deeply dyed 3: Stained 2: Lightly stained 1: Very lightly stained 0: Not stained at all <Fiber adhesion> The adhesion of fibers after dyeing was evaluated based on the hardness of the fiber bundle when touched by hand and the state of separation of individual fibers, according to the following criteria. No fiber adhesion: The fiber bundles are soft and separate easily into individual fibers. Fiber adhesion: The fiber bundles are stiff, and the individual fibers are tightly bound together and do not separate.

[0083] (Manufacturing Example 1) <Macromonomer production> 554 g of CuBr was placed in a 2 L separable flask equipped with a reflux condenser and stirrer, and the flask was purged with nitrogen. Next, 73.8 mL of acetonitrile was added, and the separable flask was placed in a 70°C oil bath and the contents were stirred for 30 minutes. Then, 132 g of 2-methoxyethyl acrylate, 14.4 mL of methyl 2-bromopropionate, and 4.69 mL of pentamethyldiethylenetriamine were added to the separable flask to start the reaction. 528 g of 2-methoxyethyl acrylate was added dropwise over 90 minutes while heating and stirring at 70°C, and the mixture was heated and stirred for another 80 minutes at 70°C. The reaction mixture was diluted with toluene, passed through an activated alumina column, and then the volatile components were removed by vacuum distillation to obtain poly(2-methoxyethyl acrylate) with one end Br group. 800 mL of methanol was placed in a flask and cooled to 0°C. 130 g of potassium t-butoxy was added in several portions. Then, while maintaining the flask at 0°C, 200 mL of methanol solution (concentration 0.5 g / mL) of acrylic acid (100 g) was added dropwise. After the reaction mixture was allowed to return from 0°C to room temperature (20 ± 5°C), potassium acrylate (CH2=CHCO2K) was obtained by removing volatile components of the reaction mixture under reduced pressure. In a 500 mL flask equipped with a reflux condenser, 150 g of the brin-grouped poly(2-methoxyethyl acrylate) obtained above, 7.45 g of the potassium acrylate obtained above, and 150 mL of dimethylacetamide were charged and heated and stirred at 70°C for 3 hours. Subsequently, dimethylacetamide was removed from the reaction mixture by distillation, the reaction mixture was dissolved in toluene, passed through an activated alumina column, and then the toluene was removed by distillation to obtain the acryloyl-grouped poly(2-methoxyethyl acrylate) macromonomer. The number-average molecular weight of the obtained acryloyl-grouped poly(2-methoxyethyl acrylate) macromonomer was 6000, and the molecular weight distribution (mass-average molecular weight / number-average molecular weight) was 1.24.

[0084] (Manufacturing example 2) <Manufacturing of Modacrylic Resin> Modacryl resin was prepared as polymer (A). 54 parts by mass of vinyl chloride, 7.5 parts by mass of acrylonitrile, 3 parts by mass of poly(2-methoxyethyl) macromonomer with one end acryloyl group obtained in Production Example 1, 210 parts by mass of deionized water, 0.4 parts by mass of partially saponified polyvinyl acetate (saponification degree approximately 70 mol%, average degree of polymerization 1700), and 0.75 parts by mass of 1,1,3,3-tetramethylbutyl peroxyneodecanoate were charged into the polymerization reactor, and the mixture was stirred and dispersed for 15 minutes. Then, the temperature in the polymerization reactor was raised to 50°C to start polymerization. Polymerization was carried out at 50°C for 4 hours, then raised to 52.5°C for a further 2 hours, and then raised to 55°C for a further 2 hours. During polymerization, 35.5 parts by mass of acrylonitrile and 0.5 parts by mass of 2-mercaptoethanol were continuously added at a constant rate from immediately after the start of polymerization until 7 hours later. After recovering the unreacted vinyl chloride monomer in the polymerization reactor, the slurry was discharged. The obtained slurry was dehydrated and dried in a hot air dryer at 60°C for 24 hours to obtain modacryl resin. The obtained modacryl resin was a graft polymer consisting of 41.2% by mass of constituent units derived from acrylonitrile, 55.8% by mass of constituent units derived from vinyl chloride, and 3.0% by mass of constituent units derived from poly(2-methoxyethyl acrylate), with a mass-average molecular weight of approximately 52,000. The obtained modacryl resin also had a glass transition temperature of 83.7°C.

[0085] (Example 1) <Manufacturing of Modacrylic Resin Composition> Polymer (A) consists of 79 parts by mass of modacryl resin obtained in Production Example 2, Polymer (B) consists of 20 parts by mass of poly(glycidyl methacrylate) (a homopolymer of glycidyl methacrylate, manufactured by NOF Corporation, product name "Marproof G-01100", mass-average molecular weight 10000, glass transition temperature 61.7℃), and Polymer (C) consists of poly(diallyldimethylammonium chloride) (a homopolymer of diallyldimethylammonium chloride) To 100 parts by mass of 1 part by mass of German polymer, Senka Co., Ltd., product name "Senka Floc DC-10B", 2.5 parts by mass of plasticizer (dimethyl sulfone), 3 parts by mass of epoxy heat stabilizer, 1.5 parts by mass of hydrotalcite heat stabilizer, 0.3 parts by mass of Ca-Zn heat stabilizer, 2 parts by mass of β-diketone heat stabilizer, 0.38 parts by mass of lubricant, and 3 parts by mass of processing aid were added and mixed using a Henschel mixer to obtain a powder mixture. Next, the powder mixture was extruded using a laboratory extruder (Toyo Seiki Co., Ltd., model number "4C150", combination of 20 mm extrusion unit and 2 mm strand nozzle) to obtain strands. The extruder was operated in a temperature range of 120 to 150°C. After air cooling the obtained strands, they were pelletized to obtain a modacrylic resin composition (pellets). <Manufacturing of Modacrylic Fibers> The modacryl resin composition (pellets) obtained above was extruded using a laboratory extruder (Toyo Seiki Co., Ltd., model "4C150", 20mm extrusion unit, downward die for melt viscosity measurement, with a hole cross-sectional area of ​​0.0793mm²). 2 Using a spinning nozzle combination with 12 holes and a cocoon-shaped cross-sectional shape for the holes, melt spinning was performed by extruding the material at a cylinder temperature of 130-160°C and a nozzle temperature of 235±5°C. The extruded molten mixture was taken up with a nozzle draft of approximately 6.8 times to obtain an undrawn yarn with a single fiber fineness of 150 dtex. The obtained undrawn yarn was dry-heat-stretched to a draw ratio of 3 times in a dry heat atmosphere at 100°C, and then relaxed at 100°C to a relaxation rate of 5% to obtain a drawn yarn (modacrylic fiber) with a single fiber fineness of 55.6 dtex.

[0086] (Example 2) A modacryl resin composition (pellets) and modacryl fibers (single fiber fineness of 55.6 dtex) were prepared in the same manner as in Example 1, except that the total amount was 100 parts by mass, consisting of 89 parts by mass of modacryl resin, 10 parts by mass of poly(glycidyl methacrylate), and 1 part by mass of poly(diallyldimethylammonium chloride).

[0087] (Example 3) A modacryl resin composition (pellets) and modacryl fibers (single fiber fineness of 55.6 dtex) were prepared in the same manner as in Example 1, except that the total amount was 100 parts by mass, consisting of 94 parts by mass of modacryl resin, 5 parts by mass of poly(glycidyl methacrylate), and 1 part by mass of poly(diallyldimethylammonium chloride).

[0088] (Example 4) A modacryl resin composition (pellets) and modacryl fibers (single fiber fineness of 55.6 dtex) were prepared in the same manner as in Example 1, except that the total amount was 100 parts by mass, consisting of 88 parts by mass of modacryl resin, 10 parts by mass of poly(glycidyl methacrylate), and 2 parts by mass of poly(diallyldimethylammonium chloride).

[0089] (Comparative Example 1) A modacryl resin composition (pellets) and modacryl fibers (single fiber fineness of 55.6 dtex) were prepared in the same manner as in Example 1, except that poly(glycidyl methacrylate) and poly(diallyldimethylammonium chloride) were not used, and modacryl resin was used in a quantity of 100 parts by mass.

[0090] (Comparative Example 2) A modacryl resin composition (pellets) and modacryl fibers (single fiber fineness of 55.6 dtex) were prepared in the same manner as in Example 1, except that a vinyl acetate-vinylpyrrolidone copolymer (40% by mass vinyl acetate, 60% by mass vinylpyrrolidone, mass-average molecular weight 65,000, glass transition temperature 45.2°C) was used instead of poly(glycidyl methacrylate), poly(diallyldimethylammonium chloride) was not used, and the total amount of modacryl resin was 80 parts by mass and vinyl acetate-vinylpyrrolidone copolymer was 20 parts by mass, for a total of 100 parts.

[0091] (Comparative Example 3) A modacryl resin composition (pellets) and modacryl fibers (single fiber fineness of 55.6 dtex) were prepared in the same manner as in Example 1, except that poly(diallyldimethylammonium chloride) was not used, and the total amount of modacryl resin was 80 parts by mass and poly(glycidyl methacrylate) was 20 parts by mass, for a total of 100 parts.

[0092] (Comparative Example 4) A modacryl resin composition (pellets) and modacryl fibers (single fiber fineness of 55.6 dtex) were prepared in the same manner as in Example 1, except that poly(glycidyl methacrylate) was not used, and the total amount of modacryl resin was 99 parts by mass and poly(diallyldimethylammonium chloride) was 1 part by mass.

[0093] (Comparative Example 5) A modacryl resin composition (pellets) was prepared in the same manner as in Example 1, except that the composition consisted of 75 parts by mass of modacryl resin, 20 parts by mass of poly(glycidyl methacrylate), and 5 parts by mass of poly(diallyldimethylammonium chloride), totaling 100 parts by mass. Melt spinning was attempted, but yarn breakage occurred when taking back the molten mixture discharged from the nozzle, making it impossible to obtain undrawn yarn.

[0094] The solubility of polymer (B) used in the examples and comparative examples in benzyl alcohol and water was evaluated as described above, and the results are shown in Table 1 below.

[0095] [Table 1]

[0096] The dyeability of the fibers obtained in Examples 1-4 and Comparative Examples 1-4 after dyeing treatment, and the adhesion of the fibers after dyeing, were evaluated as described above, and the results are shown in Table 2 below.

[0097] [Table 2]

[0098] From the results in Table 2 above, the fibers of Examples 1 to 4 obtained from resin compositions (pellets) containing predetermined amounts of polymer (A), polymer (B), and polymer (C) showed good dyeability with human hair dyes containing acid dyes. Furthermore, the fibers of Examples 1 to 4 did not exhibit adhesion between fibers after dyeing treatment and can be suitably used as artificial hair, etc.

[0099] On the other hand, the fibers of Comparative Example 1, obtained from a resin composition (pellets) containing only polymer (A) and not polymer (B) and polymer (C), could not be dyed with a human hair dye containing an acid dye. Furthermore, in Comparative Example 2, which used the water-soluble polymer (B), the fibers exhibited adhesion to each other after washing. This is presumed to be because the water-soluble polymer (B) dissolved onto the fiber surface during washing, causing the fibers to adhere to each other. Furthermore, the fibers of Comparative Example 3, obtained from a resin composition (pellets) containing polymer (A) and polymer (B) but not containing a predetermined polymer (C), and the fibers of Comparative Example 4, obtained from a resin composition (pellets) containing polymer (A) and polymer (C) but not containing a predetermined polymer (B), exhibited poor dyeability with human hair dyes containing acid dyes.

[0100] The present invention is not particularly limited, but preferably includes, for example, the following embodiments. [1] A resin composition comprising polymer (A), polymer (B), and polymer (C), The polymer (A) contains 35% by mass or more of constituent units derived from acrylonitrile, The polymer (A) has a glass transition temperature of 80 to 110°C. The polymer (B) contains 45% by mass or more of constituent units derived from one or more monomers (b) selected from the group consisting of (meth)acrylic acid ester monomers and vinyl carboxylate ester monomers. The polymer (B) is water-insoluble and has a glass transition temperature of 20°C or higher and less than 80°C. The polymer (C) is a cationic polymer containing more than 65% by mass of constituent units derived from monomer (c) which contains one or more functional groups selected from the group consisting of amino groups and quaternary ammonium groups. A resin composition in which, when the total mass of polymer (A), polymer (B), and polymer (C) is 100% by mass, the content of polymer (A) is 70 to 94.9% by mass, the content of polymer (B) is 5 to 29.9% by mass, and the content of polymer (C) is 0.1 to 4% by mass. [2] The resin composition according to [1], wherein the monomer (c) is one or more selected from the group consisting of diallyldialkylammonium salts, amino group-containing (meth)acrylic acid esters, and quaternary ammonium group-containing (meth)acrylic acid esters. [3] The resin composition according to [1] or [2], wherein the polymer (A) comprises 35 to 84% by mass of structural units derived from acrylonitrile, 15 to 64% by mass of structural units derived from one or more halogen-containing monomers (a1) selected from the group consisting of vinyl halides and vinylidene halides, and 1 to 30% by mass of structural units derived from a macromonomer (a2) having a polymer of ethylenically unsaturated monomer (d) as its main chain. [4] The resin composition according to [3], wherein the macromonomer (a2) has at least one reactive functional group per molecule at the end of the molecular fragment. [5] The resin composition according to [4], wherein the reactive functional group is a polymerizable carbon-carbon double bond functional group represented by the following general formula (1). CH2=C(R)-C(O)O- (1) (However, in general formula (1), R represents hydrogen or an organic group having 1 to 20 carbon atoms.) [6] The resin composition according to any one of [3] to [5], wherein the ethylenically unsaturated monomer (d) is one or more selected from the group consisting of (meth)acrylic acid ester monomers, styrene monomers, nitrile group-containing vinyl monomers, and amide group-containing vinyl monomers. [7] A synthetic fiber comprising the resin composition described in any one of items [1] to [6]. [8] A method for producing synthetic fibers, comprising the step of melt-spinning a resin composition described in any one of items [1] to [6].

Claims

1. A resin composition comprising polymer (A), polymer (B), and polymer (C), The polymer (A) contains 35% by mass or more of constituent units derived from acrylonitrile, The polymer (A) has a glass transition temperature of 80 to 110°C. The polymer (B) contains 45% by mass or more of constituent units derived from one or more monomers (b) selected from the group consisting of (meth)acrylic acid ester monomers and vinyl carboxylate ester monomers. The polymer (B) is water-insoluble and has a glass transition temperature of 20°C or higher and less than 80°C. The polymer (C) is a cationic polymer containing more than 65% by mass of constituent units derived from monomer (c) which contains one or more functional groups selected from the group consisting of amino groups and quaternary ammonium groups. A resin composition in which, when the total mass of polymer (A), polymer (B), and polymer (C) is 100% by mass, the content of polymer (A) is 70 to 94.9% by mass, the content of polymer (B) is 5 to 29.9% by mass, and the content of polymer (C) is 0.1 to 4% by mass.

2. The resin composition according to claim 1, wherein the monomer (c) is one or more selected from the group consisting of diallyl dialkylammonium salts, amino group-containing (meth)acrylic acid esters, and quaternary ammonium group-containing (meth)acrylic acid esters.

3. The resin composition according to claim 1, wherein the polymer (A) contains 35 to 84% by mass of structural units derived from acrylonitrile, 15 to 64% by mass of structural units derived from one or more halogen-containing monomers (a1) selected from the group consisting of vinyl halides and vinylidene halides, and 1 to 30% by mass of structural units derived from a macromonomer (a2) having a polymer of ethylenically unsaturated monomer (d) as its main chain.

4. The resin composition according to claim 3, wherein the macromonomer (a2) has at least one reactive functional group per molecule at the end of the molecular fragment.

5. The resin composition according to claim 4, wherein the reactive functional group is a polymerizable carbon-carbon double bond functional group represented by the following general formula (1). CH 2 =C(R)-C(O)O- (1) (However, in general formula (1), R represents hydrogen or an organic group having 1 to 20 carbon atoms.)

6. The resin composition according to claim 3, wherein the ethylenically unsaturated monomer (d) is one or more selected from the group consisting of (meth)acrylic acid ester monomers, styrene monomers, nitrile group-containing vinyl monomers, and amide group-containing vinyl monomers.

7. A synthetic fiber comprising the resin composition according to any one of claims 1 to 6.

8. A method for producing synthetic fibers, comprising the step of melt-spinning a resin composition according to any one of claims 1 to 6.

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