Microplastic fiber reducing agent for fibers

Abstract

To obtain a new agent for reducing microplastic fibers for fibers, capable of reducing the amount of the microplastic fibers generated when fibers or fiber products containing synthetic fibers are washed, etc., and to provide a method for reducing the microplastic fibers.SOLUTION: Fibers and fiber products containing synthetic fibers are treated with a microplastic fiber reducing agent for fibers containing a cationic polymer having a storage modulus of 4. 1Hz or more at a strain of 1% when a 1 mass% aqueous solution is subjected to dynamic viscoelasticity measurement at a strain of 0.01% to 1000% under conditions of 25 °C and a frequency of 0Pa.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a microplastic fiber reducing agent for textiles and a method for reducing microplastic fibers for textiles. [Background technology]

[0002] In recent years, there has been growing concern about the impact of plastics on the marine environment, including the risk that tiny plastic particles, such as microplastic beads, may end up in the ocean and become ingested by sea turtles, seabirds, and fish (and ultimately humans). Microplastic pollution also includes microfibers (less than 5mm in length) from synthetic clothing. These synthetic microfibers are shed during textile cleaning (washing, scouring, etc.) and are released into the ocean, coasts, rivers, lakes, etc., and some of them are thought to end up in the soil.

[0003] It is known to use cellulose derivatives as care compounds that can reduce the pilling and fuzzing of clothing. For example, Patent Document 1 discloses a clothing care composition containing (a) a specific nonionic surfactant, (b) a polysaccharide polymer, and (c) a surfactant other than component (a). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2020-100723 Summary of the Invention [Problem to be solved by the invention]

[0005] However, it has been found that simply reducing friction at the contact points between fibers is not sufficient to suppress the generation of microplastic fibers that are generated from fibers when they are washed. The present invention provides a novel microplastic fiber-reducing agent for textiles and a novel method for reducing microplastic fibers, which reduce the amount of microplastic fibers generated from textiles when the textiles are washed. Microplastic fibers in the present invention refer to fibrous microplastics, with fiber lengths generally ranging from 0.1 μm to less than 5 mm. Microplastic fibers are known to be contained in wastewater from washing textile products containing synthetic fibers, and are thought to be formed by the shedding of some of the synthetic fibers from such textile products. Microplastic fibers refer to synthetic fiber waste and laundry waste. The method for reducing microplastic fibers in the present invention means a method for reducing the generation and emission of microplastic fibers from fibers and textile products. In the present invention, "fiber" refers to a fiber containing one or more types of synthetic fibers, and may also contain one or more types of non-synthetic fibers. The fiber in the present invention may be in the form of a thread or a test piece having a predetermined size. Furthermore, products manufactured using the fiber are referred to as textile products. The "fiber" targeted by the microplastic fiber-reducing agent for fibers and the microplastic fiber reduction method of the present invention includes both the fiber and the textile product manufactured using the fiber. In the present invention, washing fibers refers to the act of exerting a physical and / or chemical action on fibers via a treatment liquid containing the microplastic fiber-reducing agent for fibers of the present invention or the fiber treatment composition described below. The term "washing" as used herein is not limited to the act of actually removing dirt, impurities, etc. from fibers, but may be any act of exerting a physical and / or chemical action on fibers so as to enable the removal of dirt, impurities, etc. from fibers during the fiber manufacturing process or the textile product recycling process. Specifically, washing in the present invention is preferably at least one of washing and fiber scouring. For example, washing includes at least one of a washing process, a rinsing process, a treatment process using a laundry aid such as a fabric softener, or a spin-drying process. Fiber scouring is the act of removing impurities, etc., adhering to fibers before dyeing, using, for example, a surfactant. The washing in the present invention may be performed using a machine such as a washing machine, or by hand washing. [Means for solving the problem]

[0006] The present invention relates to a microplastic fiber reducing agent for fibers, which comprises a cationic polymer and, when a 1% by mass aqueous solution thereof is subjected to dynamic viscoelasticity measurement at 25°C and a frequency of 1 Hz at a strain of 0.01% to 1000%, has a storage modulus of 4.0 Pa or more at a strain of 1%.

[0007] The present invention also relates to a method for reducing microplastic fibers, which comprises a step of contacting fibers with a microplastic-reducing agent for fibers comprising a cationic polymer or a fiber treatment composition containing the microplastic-reducing agent for fibers. [Effects of the Invention]

[0008] According to the present invention, a novel microplastic fiber reducing agent for textiles and a method for reducing microplastic fibers are provided, which reduce the amount of microplastic fibers generated from textiles during cleaning and other processes. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, microplastic fibers will also be referred to as "MPF." Unless otherwise specified, the reason why each preferred embodiment is preferred is "from the perspective of further reducing microplastic fibers (MPF) generated from the fibers." The same reason will also be described as "from the perspective of improving MPF reduction ability."

[0010] <MPF reducing agent for textiles> The MPF reducing agent for fibers of the present invention contains a cationic polymer. The MPF reducing agent for fibers of the present invention may consist essentially of a cationic polymer.

[0011] The MPF reducer for fibers of the present invention may be an MPF ​​reducer for textile products. The MPF reducer for fibers of the present invention may also be an MPF ​​reducer for synthetic fibers, or even an MPF ​​reducer for synthetic textile products.

[0012] Furthermore, the MPF reducer for fibers of the present invention may be an MPF ​​generation reducer for fibers that reduces the amount of MPF generated from synthetic fibers when the fibers are washed.

[0013] <Cationic polymer> In the present invention, a cationic polymer refers to a polymer having a positive charge density, i.e., a polymer in which the sum of the cationic charge density of the polymer and the anionic charge density of the polymer is a positive value. Here, the cationic charge density (meq / g) of a polymer is expressed in eq units by multiplying the total number of moles of cationic groups and substituents that can become cations by adding protons in water contained in 1 mol of the polymer by the positive charge valence when each cationic group and substituent becomes a cationic group, and dividing this value by the mass (kg) of 1 mol of the polymer. Furthermore, the anionic charge density (meq / g) of a polymer is expressed in eq units by multiplying the total number of moles of anionic groups and substituents that can become anions by removing protons in water contained in 1 mol of the polymer by the negative charge valence when each anionic group and substituent becomes an anionic group, and dividing this value by the mass (kg) of 1 mol of the polymer (a negative value). In the present invention, both the cationic charge density of a polymer and the anionic charge density of a polymer are calculated values. From the viewpoint of improving the MPF reduction ability, the cationic group is preferably one or more selected from (primary to quaternary) ammonio groups (hereinafter sometimes referred to as ammonio groups) and amino groups (-NH2 groups). The amino groups are converted into cationic ammonio groups (-NH2 groups) by adding a proton in water depending on the pH. + In the present invention, cationic groups are included in the cationic groups. That is, when calculating the cationic charge density, 1 mol of amino groups is calculated as +1 eq. In the following explanation, for convenience, cationic groups include both ammonio groups and amino groups, and are explained as ammonio groups.

[0014] When a 1% by mass aqueous solution of the cationic polymer of the present invention is subjected to dynamic viscoelasticity measurement at a strain of 0.01% to 1000% at 25°C and a frequency of 1 Hz, the storage modulus at a strain of 1% is 4.0 Pa or more, preferably 4.5 Pa or more, from the viewpoint of improving the MPF reduction ability, and from the same viewpoint is 100 Pa or less, preferably 50 Pa or less, more preferably 25 Pa or less, and even more preferably 10 Pa or less.

[0015] Furthermore, when a 1% by mass aqueous solution of the cationic polymer of the present invention is subjected to dynamic viscoelasticity measurement at a shear rate of 0.005 to 5000 (1 / s) at 25°C and a frequency of 1 Hz, the shear viscosity at 0.005 (1 / s) is preferably 3.0 Pa·s or more, more preferably 4.0 Pa·s or more, and even more preferably 5.0 Pa·s or more, from the viewpoint of improving the MPF reduction ability, and from the same viewpoint, is preferably 1000 Pa·s or less, more preferably 100 Pa·s or less, even more preferably 50 Pa·s or less, and still more preferably 20 Pa·s or less.

[0016] The weight average molecular weight of the cationic polymer of the present invention is preferably 100,000 or more, more preferably 1,000,000 or more, even more preferably 3,000,000 or more, and still more preferably 5,000,000 or more, from the viewpoint of improving the MPF reduction ability, and is preferably 50,000,000 or less, more preferably 30,000,000 or less, even more preferably 20,000,000 or less, and still more preferably 10,000,000 or less, from the viewpoint of improving the fluidity of the treatment liquid described below.

[0017] The weight average molecular weight of the cationic polymer is calculated in terms of polyethylene glycol by GPC (gel permeation chromatography) under the following measurement conditions. Column: TSKgel α-M Eluent: 50mmol / L LiBr, 1% CH3COOH, ethanol / water = 3 / 7 ·Temperature: 40℃ ·Flow rate: 0.6mL / min

[0018] The charge density of the cationic polymer of the present invention is preferably +0.1 meq / g or more, more preferably +0.3 meq / g or more, even more preferably +0.5 meq / g or more, and still more preferably +0.8 meq / g or more, from the viewpoint of improving the MPF reduction ability, and is preferably +20 meq / g or less, more preferably +10 meq / g or less, even more preferably +5 meq / g or less, and still more preferably +3.5 meq / g or less, from the viewpoint of improving the adsorption to fibers.

[0019] In the present invention, the cationic polymer is preferably a polymer having an ammonio group from the viewpoint of improving the MPF reduction ability.Specific examples include a polymer of an acrylic acid ester or methacrylic acid ester having an ammonio group, and a copolymer of these monomers with one or more selected from acrylamide, methacrylamide, acrylic acid and its esters, and methacrylic acid and its esters.

[0020] The cationic polymer in the present invention is a polymer represented by the following general formula (1) from the viewpoint of improving the MPF reduction ability: [ka] (In the formula, R 1 represents a hydrogen atom or a methyl group. 2 , R 3 and R 4 each independently represents a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms; X represents -O- or -NH-; m represents an integer of 1 to 4; Z - indicates the counter anion.) It is preferable that the compound contains an ammonio group represented by the following formula:

[0021] Z - is a counter anion of the ammonio group in general formula (1), and is not particularly limited. From the viewpoint of improving MPF reduction ability, examples include one or more anions selected from alkyl sulfate ions having 1 to 3 carbon atoms, (1 / 2) sulfate ions, (1 / 3) phosphate ions, fatty acid ions having 1 to 3 carbon atoms, and halide ions. Among these, from the same viewpoint, one or more anions selected from alkyl sulfate ions and halide ions having 1 to 3 carbon atoms are preferred. Examples of alkyl sulfate ions having 1 to 3 carbon atoms include one or more anions selected from methyl sulfate ions and ethyl sulfate ions. Examples of halide ions include one or more anions selected from fluoride ions, chloride ions, bromide ions, and iodide ions. From the same viewpoint, the anion is preferably one or more anions selected from methyl sulfate ions, ethyl sulfate ions, chloride ions, and bromide ions, more preferably one or more anions selected from methyl sulfate ions, ethyl sulfate ions, and chloride ions. The counter ion of the ammonio group in general formula (1) may be of one type alone or of two or more types.

[0022] R in general formula (1) 1 From the viewpoint of improving the MPF reduction ability, R in general formula (1) is preferably a methyl group. 2 ~R 4Examples of the hydrocarbon group include a linear alkyl group, a branched alkyl group, a cyclic alkyl group, a linear alkenyl group, a branched alkenyl group, a cyclic alkenyl group, and an aryl group. From the viewpoint of improving MPF reduction ability, a linear alkyl group is preferred, and specific examples include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group, a decyl group, a dodecyl group, a tetradecyl group, a hexadecyl group, an octadecyl group, and an eicosanyl group. From the same viewpoint, a group selected from an octyl group, a nonyl group, a decyl group, a dodecyl group, a tetradecyl group, and a hexadecyl group is preferred. From the same viewpoint, X in general formula (1) is preferably -O-. From the same viewpoint, m in general formula (1) is preferably 2 or 3, and more preferably 2.

[0023] The cationic polymer in the present invention is, for example, a polymer represented by the following general formula (1a): [ka] (In the formula, R 1 , R 2 , R 3 , R 4 , X, m and Z - (These are the same as above.) It can be obtained by polymerizing a monomer represented by the following formula (also called olefin (1a)):

[0024] The cationic polymer of the present invention may be copolymerized with other monomers having a double bond (also referred to as other olefins) as appropriate. The other olefins are not limited, but from the viewpoint of improving the MPF reduction ability, it is preferable to use a monomer represented by the following general formula (2a): [ka] (In the formula, R 5 represents a hydrogen atom or a methyl group. 6 and R 7 each independently represents a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms. A monomer represented by the general formula (2) (also called olefin (2a)) is copolymerized to form a copolymer represented by the general formula (2) [ka] (In the formula, R 5 , R 6 and R 7 (These are the same as above.) By introducing a constitutional unit represented by general formula (3) [ka] (In the formula, R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7 , X, m and Z - p1 and q1 represent the content of each structural unit derived from olefin (1a) and olefin (2a) in the total structural units, respectively, and 0 <p1<1かつ0<q1<1かつp1+q1≦1である。) Alternatively, the cationic polymer may have a structural unit represented by the following formula:

[0025] R in general formulas (2a), (2) and (3) 5 is preferably a hydrogen atom from the viewpoint of improving the MPF reduction ability.

[0026] R in general formulas (2a), (2) and (3) 6 and R 7Examples of the hydrocarbon group include a linear alkyl group, a branched alkyl group, a cyclic alkyl group, a linear alkenyl group, a branched alkenyl group, a cyclic alkenyl group, and an aryl group. From the viewpoint of improving the MPF reduction ability, a linear alkyl group is preferred, and specific examples thereof include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group, a decyl group, a dodecyl group, a tetradecyl group, a hexadecyl group, an octadecyl group, and an eicosanyl group. From the same viewpoint, a group selected from a methyl group, an ethyl group, a propyl group, and a butyl group is preferred.

[0027] The copolymerization of the olefin (1a) and the olefin (2a) may be carried out under ordinary copolymerization conditions, and may be, for example, any of alternating copolymerization, block copolymerization, random copolymerization, and the like.

[0028] From the viewpoint of improving the MPF reduction ability, p1 in general formula (3) is preferably 0.01 or more, more preferably 0.025 or more, even more preferably 0.05 or more, and still more preferably 0.075 or more, and from the viewpoint of economic efficiency, it is preferably 0.9 or less, more preferably 0.6 or less, even more preferably 0.3 or less, and still more preferably 0.125 or less. Furthermore, from the viewpoint of improving the MPF reduction ability, q1 in general formula (3) is preferably 0.3 or more, more preferably 0.6 or more, and even more preferably 0.85 or more, and from the same viewpoint, it is preferably 0.99 or less, more preferably 0.975 or less, and even more preferably 0.95 or less.

[0029] Also, olefin (1a) and the following general formula (4a) [ka] (In the formula, R 8 represents a hydrogen atom or a methyl group. 9 represents a hydrogen ion, an alkali metal ion, a (1 / 2) alkaline earth metal ion, an ammonium ion, or an alkylammonium ion having an alkyl group having 1 to 4 carbon atoms. A monomer represented by the general formula (4) (also called olefin (4a)) is copolymerized to form a copolymer represented by the general formula (4) [ka] (In the formula, R 8 and R 9 (These are the same as above.) By introducing a constitutional unit represented by the general formula (5) [ka] (In the formula, R 1 , R 2 , R 3 , R 4 , R 8 , R 9 , X, m and Z - p2 and r2 represent the content of each structural unit derived from olefin (1a) and olefin (4a) in the total structural units, respectively, and 0 <p2<1かつ0<r2<1かつp2+r2≦1である。) It is preferable to use a cationic polymer containing a structural unit represented by the following formula:

[0030] R in general formulas (4a), (4) and (5) 8 is preferably a hydrogen atom from the viewpoint of improving the MPF reduction ability, and from the same viewpoint, R 9 is preferably a sodium ion.

[0031] From the viewpoint of improving the MPF reduction ability, p2 in general formula (5) is preferably 0.05 or more, more preferably 0.1 or more, and even more preferably 0.15 or more, and from the viewpoint of economic efficiency, it is preferably 0.8 or less, more preferably 0.6 or less, and even more preferably 0.4 or less. Furthermore, from the viewpoint of improving the MPF reduction ability, r2 in general formula (5) is preferably 0.2 or more, more preferably 0.4 or more, and even more preferably 0.6 or more, and from the same viewpoint, it is preferably 0.9 or less, more preferably 0.8 or less, and even more preferably 0.7 or less.

[0032] The copolymerization of the olefin (1a) and the olefin (4a) may be carried out under ordinary copolymerization conditions, and may be, for example, any of alternating copolymerization, block copolymerization, random copolymerization, and the like.

[0033] Furthermore, from the viewpoint of improving the MPF reduction ability, the cationic polymer in the present invention is a polymer having the general formula (6) obtained by mixing and copolymerizing (1a), (2a), and (4a) [ka] (In the formula, R 1 , R 2 , R 3 , R 4 , R 5 , R 6 , R 7 , R 8 , R 9 , X, m and Z - p3, q3, and r3 each represent the content of the structural units derived from olefin (1a), olefin (2a), and olefin (4a) in the total structural units, and 0 <p3<1かつ0<q3<1かつ0<r3<1かつp3+q3+r3≦1である。) The cationic polymer may be represented by the formula:

[0034] From the viewpoint of improving the MPF reduction ability, p3 in general formula (6) is preferably 0.2 or more, more preferably 0.3 or more, even more preferably 0.4 or more, and from the same viewpoint, it is preferably 0.8 or less, more preferably 0.7 or less, even more preferably 0.6 or less. From the same viewpoint, q3 is preferably 0.05 or more, more preferably 0.1 or more, even more preferably 0.15 or more, and from the same viewpoint, it is preferably 0.5 or less, more preferably 0.4 or less, even more preferably 0.3 or less. From the same viewpoint, r3 is preferably 0.1 or more, more preferably 0.15 or more, even more preferably 0.2 or more, and from the same viewpoint, it is preferably 0.6 or less, more preferably 0.5 or less, even more preferably 0.4 or less.

[0035] In addition, in the cationic polymer represented by the general formula (5) or (6), a part of the constitutional units derived from the olefin (4a) is replaced with a constitutional unit represented by the general formula (7), from the viewpoint of improving the MPF reduction ability. [ka] (In the formula, X 1 and X 2 each independently represents -O- or -NH-; m1 represents an integer of 1 or more and 4 or less; s1 represents a number of 1 or more and 30 or less; R 8 This shows the same content as above.) It may also contain a structure in which the hydroxyl group is replaced by a crosslinking structural unit represented by the following formula:

[0036] The crosslinking structural unit represented by general formula (7) is a crosslinking structural unit represented by general formula (7a) together with olefin (1a) (and olefin (4a)) when obtaining a cationic polymer having a structure represented by general formula (5) or (6). [ka] (In the formula, R 8 , X 1 , X 2 , m1 and s1 each have the same meaning as above.) or by copolymerizing diolefin (7a) together with olefin (1a) and olefin (2a) (and olefin (4a)).

[0037] The crosslinking structural unit represented by general formula (7) can be prepared by reacting a polymer having a structure represented by general formula (5) or (6) with a polymer having a structure represented by general formula (8) [ka] (In the formula, X 1 , X 2 , m1, and s1 each have the same meaning as above.) The crosslinking agent can be used to introduce the compound.

[0038] The crosslinking structural unit represented by general formula (7) is preferably introduced into a cationic polymer having a structure represented by (5) or (6) by copolymerizing diolefin (7a) together with olefin (1a) (and olefin (4a)) or by copolymerizing diolefin (8a) together with olefin (1a) and olefin (2a) (and (4a)), in view of high crosslinking efficiency.

[0039] The crosslinked structure of the cationic polymer may be a crosslinked structure obtained by copolymerizing a diolefin such as isoprene, norbornadiene, or divinylbenzene in addition to the diolefin (7a).

[0040] When the cationic polymers represented by general formulas (5) and (6) contain a crosslinked structure represented by general formula (7), the content of the crosslinked structure represented by general formula (8) in the cationic polymer (hereinafter sometimes referred to as r4) is greater than 0 and less than or equal to r2 and less than or equal to r3, respectively.

[0041] X in general formula (8) 1 In the case of -NH-, the R of the structural unit derived from olefin (4a) 9 By replacing X with a hydrogen atom, crosslinking can be achieved by dehydration condensation to form an acid amide bond. 1 In the case of -O-, R of the structural unit derived from olefin (4a) 9 By changing X to a hydrogen atom, cross-linking by an ester bond can be achieved by dehydration condensation. 1 is preferably —O—.

[0042] X in general formulas (7) and (8) 2 is preferably -O- from the viewpoint of improving the MPF reducing ability. From the same viewpoint, m1 is preferably 2 or 3, and more preferably 2. From the viewpoint of improving the MPF reducing ability, s1 is preferably 1 or more, more preferably 3 or more, and even more preferably 10 or more, and from the same viewpoint, is preferably 30 or less, more preferably 25 or less, and even more preferably 20 or less.

[0043] The content of the crosslinking structural unit represented by general formula (7) in the cationic polymer is the mole ratio of the number of crosslinking structural units represented by general formula (7) to the number of all structural units in the cationic polymer, and ([number of moles of crosslinking structural units] / [total number of moles of all structural units]) × 100 (%) is, from the viewpoint of improving the MPF reduction ability, preferably 0.00001% or more, more preferably 0.0001% or more, even more preferably 0.005% or more, and even more preferably 0.003% or more, and from the same viewpoint, is preferably 0.04% or less, more preferably 0.02% or less, even more preferably 0.01% or less, and even more preferably 0.004% or less.

[0044] The ratio of r4 to r2 ([r4 / r2] × 100(%)) and the ratio of r4 to r3 ([r4 / r3] × 100(%)) are each referred to as the crosslinking rate of the structural unit derived from olefin (4a). From the viewpoint of improving the MPF reduction ability, this crosslinking rate is preferably 80% or more, more preferably 85% or more, and even more preferably 90% or more, and from the same viewpoint, it is preferably 100% or less, more preferably 97% or less, and even more preferably 95% or less.

[0045] In addition, the cationic polymer represented by the general formula (5) or (6) may be a polymer in which a part of the structural units derived from the olefin (1a) is replaced with a structural unit derived from the olefin (1b) [ka] (In the formula, R 1 , R 2 , R 3 , X and m are the same as those defined above.) When the structural unit derived from the olefin (1b) is replaced with a structural unit derived from the olefin (4a), the structural unit derived from the olefin (1b) undergoes dehydration condensation with the structural unit derived from the olefin (4a) to form an amide bond and crosslink the structural unit, and a compound represented by the general formula (9) [ka] (In the formula, R 1, R 8 , X 1 , R 2 and m have the same meanings as above.) The crosslinked structural unit may also be represented by the following formula:

[0046] The content of the crosslinking structural unit represented by general formula (9) in the cationic polymer (hereinafter, sometimes referred to as p4) is greater than 0 and less than the aforementioned p2 and p3, respectively.

[0047] The content of the crosslinking structural unit represented by general formula (9) in the cationic polymer is the mole ratio of the number of crosslinking structural units represented by general formula (9) to the number of all structural units in the cationic polymer, and ([number of moles of crosslinking structural units] / [total number of moles of all structural units]) × 100 (%) is, from the viewpoint of improving the MPF reduction ability, preferably 0.00001% or more, more preferably 0.0001% or more, even more preferably 0.0005% or more, still more preferably 0.003% or more, and from the same viewpoint, preferably 0.04% or less, more preferably 0.02% or less, even more preferably 0.01% or less, still more preferably 0.004% or less.

[0048] From the viewpoint of improving the MPF reduction ability, the crosslinking rate of the structural units derived from olefin (1a), expressed as [p4 / p2] × 100(%) or [p4 / p3] × 100(%), is preferably 80% or more, more preferably 85% or more, even more preferably 90% or more, and is preferably 100% or less, more preferably 97% or less, even more preferably 95% or less.

[0049] In addition to the structural units represented by general formula (1), (3), (5), (6), (8), or (9), the cationic polymer of the present invention may contain structural units derived from (meth)acrylic acid, alkyl esters of (meth)acrylic acid having 1 to 4 carbon atoms, 2-hydroxyethyl esters of (meth)acrylic acid, (meth)acrylic acid amide, styrene, vinyl sulfonic acid (salts), vinylbenzene sulfonic acid (salts), (meth)acrylic acid ester alkyl sulfonic acid (salts), (meth)acrylamide alkyl sulfonic acid (salts), etc. From the viewpoint of improving the MPF reduction ability, the content of structural units other than those represented by general formula (1), (3), (5), (6), (8), or (9) in the cationic polymer is preferably 10% or less, more preferably 5% or less, and even more preferably 0%.

[0050] The cationic polymer may be either a polymer consisting of a structural unit represented by general formula (1), (3), (5), (6), (8) or (9), or a polymer containing a structural unit such as the above-mentioned (meth)acrylic acid in addition to these structural units. However, from the viewpoint of improving the MPF reduction ability, the cationic polymer is preferably a polymer consisting of a structural unit represented by general formula (3) or (5) as a structural unit.

[0051] <Fiber treatment composition> The fiber treatment composition of the present invention contains the MPF reducer for fibers.

[0052] From the viewpoint of ease of handling, the fiber treatment composition of the present invention preferably contains a solvent, and particularly preferably water. The water is preferably impurity-free and moderately purified water. The water may be well water or industrial water, but tap water, purified water, or ion-exchanged water is preferred from the viewpoint of improving the MPF reduction ability. Water can be the balance other than the MPF reducer for fibers made of a cationic polymer and the optional components described below. The fiber treatment composition of the present invention contains water in an amount of preferably 10% by mass or more, more preferably 20% by mass or more, and even more preferably 30% by mass or more, from the viewpoint of stability of a composition containing the MPF reducer for fibers of the present invention and optional components described below, and from the same viewpoint, preferably 90% by mass or less, more preferably 85% by mass or less, and even more preferably 80% by mass or less.

[0053] When the fiber treatment composition of the present invention contains water, the content of the fiber MPF reducer in the fiber treatment composition is, from the viewpoint of improving the MPF reduction ability, preferably 0.001% by mass or more, more preferably 0.01% by mass or more, even more preferably 0.1% by mass or more, and still more preferably 0.5% by mass or more, and from the viewpoint of appropriate fluidity of the fiber treatment composition, preferably 30% by mass or less, more preferably 10% by mass or less, even more preferably 5% by mass or less, and still more preferably 1.5% by mass or less.

[0054] When the fiber treatment composition of the present invention contains water, the pH of the fiber treatment composition at 25°C, measured by the method described below, is preferably 4 or more, more preferably 5 or more, from the viewpoint of improving the MPF reduction ability, and from the same viewpoint, is preferably 12 or less, more preferably 11 or less. [pH measurement method] A pH measurement composite electrode (HORIBA glass ground sleeve type) is connected to a pH meter (HORIBA pH / ion meter F-23) and powered on. A saturated potassium chloride aqueous solution (3.33 mol / L) is used as the pH electrode internal solution. Next, a 100 mL beaker is filled with a pH 4.01 standard solution (phthalate standard solution), a pH 6.86 standard solution (neutral phosphate standard solution), and a pH 9.18 standard solution (borate standard solution), and the beaker is immersed in a thermostatic bath at 25°C for 30 minutes. The pH measurement electrode is immersed in the thermostatically adjusted pH 6.86 standard solution for 3 minutes, followed by the pH 9.18 standard solution and the pH 4.01 standard solution for 3 minutes each, for calibration. The sample to be measured (the fiber treatment composition of the present invention containing water) is then adjusted to 25°C, and the pH meter electrode is immersed in the sample. The pH is measured after 1 minute.

[0055] The viscosity of the fiber treatment composition of the present invention at 25°C is preferably 15 mPa·s or less, more preferably 10 mPa·s or less, and even more preferably 5 mPa·s or less, from the viewpoint of good sprayability using a container equipped with a sprayer, and from the same viewpoint, is preferably 1.0 mPa·s or more, more preferably 1.5 mPa·s or more, and even more preferably 2.0 mPa·s or more. The viscosity of the fiber treatment composition was measured by attaching a No. 1 rotor to a B-type viscometer (model BM) manufactured by Tokyo Keiki Co., Ltd., filling the fiber treatment composition into a 200 mL tall glass beaker, adjusting the temperature to 25°C in a water bath, setting the rotor rotation speed to 60 rpm, and starting the measurement.The viscosity was measured as the reading 1 minute after the start of the measurement. The viscosity of the fiber treatment composition can be adjusted by adjusting the content of the fiber MPF reducer.

[0056] <Additional Optional Ingredients> The fiber treatment composition of the present invention may further contain, as optional components, components known to be used in detergents, fabric softeners, etc., such as the following components (1) to (12), within a range that does not affect the effects of the present invention.

[0057] (1) pH adjuster An acidic or alkaline agent may be contained as a pH adjuster. The acid agent may be one or more selected from organic acids and inorganic acids. From the viewpoint of low residue on fibers, the organic acid may be one or more selected from citric acid, malic acid, acetic acid, succinic acid, tartaric acid, fumaric acid, lactic acid, propionic acid, oxalic acid, glutaric acid, adipic acid, gallic acid, mellitic acid, cinnamic acid, salicylic acid, phthalic acid, benzoic acid, pyruvic acid, oxaloacetic acid, and aconitic acid. The inorganic acid may be one or more selected from hydrochloric acid, phosphoric acid, sulfuric acid, boric acid, and carbonic acid. Examples of alkaline agents include inorganic alkaline agents such as alkali metal hydroxides and alkali metal carbonates, and alkanolamines in which one to three of the groups bonded to the nitrogen atom are alkanol groups having from 2 to 4 carbon atoms, and the remaining groups are alkyl groups having from 1 to 4 carbon atoms or hydrogen atoms. Of these, the alkanol group is preferably a hydroxyalkyl group, and more preferably a hydroxyethyl group. Other than the alkanol group, a hydrogen atom or a methyl group is preferred, with a hydrogen atom being particularly preferred. Examples of alkanolamines include alkanolamines such as 2-aminoethanol, N-methylethanolamine, N,N-dimethylethanolamine, N,N-diethylethanolamine, diethanolamine, N-methyldiethanolamine, and triethanolamine.

[0058] (2) Chelating agents Specific examples of chelating agents include aminopolyacetic acids such as ethylenediaminetetraacetic acid, diethylenetriaminepentaacetic acid, and hydroxyethyliminodiacetic acid, or salts thereof; organic acids such as citric acid, lactic acid, tartaric acid, and malic acid, or salts thereof; 1-hydroxyethylidene-1,1-diphosphonic acid, diethylenetriaminepenta(methylenephosphonic acid), and alkali metal or lower amine salts thereof.

[0059] (3) Anti-redeposition agents and / or polymeric dispersants From the viewpoint of low residue on fibers, examples of the anti-redeposition agent and / or polymer-based dispersant include polyacrylic acid, polymaleic acid, carboxymethyl cellulose, and the like.

[0060] (4) Bleach From the viewpoint of low residue on fibers, examples of bleaching agents include hydrogen peroxide, sodium percarbonate, and sodium perborate.

[0061] (5) Bleach activator Examples of bleach activators include tetraacetylethylenediamine and bleach activators represented by formulas (I-2) to (I-7) of JP-A-6-316700.

[0062] (6) Enzymes From the viewpoint of low residue on fibers, the enzyme may be one or more enzymes selected from amylase, sucrase, maltase, lactase, pullulanase, fructofuranosidase, cellulase, protease, and lipase.

[0063] (7) Fluorescent dyes Examples of the fluorescent dye include fluorescent dyes commercially available under the trade names of Tinopal CBS (trade name, manufactured by Ciba Specialty Chemicals) and Whitex SA (trade name, manufactured by Sumitomo Chemical Co., Ltd.).

[0064] (8) Antioxidants Antioxidants include known antioxidant compounds such as 3,5-bis(1,1-dimethylethyl)-4-hydroxy-benzenepropanoic acid, methyl ester (commercially available under the trade name RALOX® 35 from Raschig USA, Arlington, Texas, United States), butylhydroxytoluene (common name: BHT), butylhydroxyanisole (common name: BHA), distyrenated cresol, ascorbic acid (common name: vitamin C), tocopherol (common name: vitamin E), coffee bean extract (chlorogenic acid), and green tea extract (catechin), or known inorganic salts such as sodium sulfite and sodium bisulfite.

[0065] (9) Antifoaming agents such as pigments, antibacterial preservatives, UV inhibitors, and silicones

[0066] (10) Organic solvents containing hydroxyl groups As the organic solvent having a hydroxyl group, one or more compounds selected from the following components (10-1) to (10-6) are used.

[0067] Component (10-1): A monohydric alcohol having an aliphatic hydrocarbon group with 2 to 6 carbon atoms Examples of the component (10-1) include monohydric alcohols selected from ethanol, 1-propanol, 2-propanol, and 1-butanol.

[0068] (10-2) Component: Dihydric to hexahydric alcohol having 2 to 6 carbon atoms Examples of the component (10-2) include dihydric or trihydric alcohols selected from ethylene glycol, propylene glycol, butylene glycol, 2-methyl-2,4-pentanediol, 1,5-pentanediol, 1,6-hexanediol, and glycerin. 2-Methyl-2,4-pentanediol is also known as hexylene glycol.

[0069] Component (10-3): Polyalkylene glycol containing alkylene glycol units having 2 to 4 carbon atoms Examples of the component (10-3) include polyalkylene glycols selected from diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, tripropylene glycol, polyethylene glycols having a weight-average molecular weight of 400 to 4,000, and polypropylene glycols having a weight-average molecular weight of 400 to 4,000.

[0070] Component (10-4): a monoalkyl ether of (mono- or poly) alkylene glycol having an alkylene glycol unit having from 2 to 4 carbon atoms and an alkyl group having from 1 to 4 carbon atoms Examples of the component (10-4) include compounds selected from diethylene glycol monomethyl ether, triethylene glycol monomethyl ether, diethylene glycol monoethyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, tripropylene glycol monomethyl ether, diethylene glycol monobutyl ether, 1-methoxy-2-propanol, and 1-ethoxy-2-propanol.

[0071] Component (10-5): Alkyl glyceryl ether having an alkyl group with 1 to 8 carbon atoms Examples of the component (10-5) include alkyl glyceryl ethers selected from 1-methyl glyceryl ether, 2-methyl glyceryl ether, 1,3-dimethyl glyceryl ether, 1-ethyl glyceryl ether, 1,3-diethyl glyceryl ether, triethyl glyceryl ether, 1-pentyl glyceryl ether, 2-pentyl glyceryl ether, 1-octyl glyceryl ether, and 2-ethylhexyl glyceryl ether.

[0072] (10-6) Component: Aromatic alkyl ether of (mono- or poly-) alkylene glycol having an alkylene glycol unit having 2 or 3 carbon atoms Examples of the component (10-6) include compounds selected from 2-phenoxyethanol, diethylene glycol monophenyl ether, triethylene glycol monophenyl ether, polyethylene glycol monophenyl ether having an average molecular weight of about 480, 2-benzyloxyethanol, and diethylene glycol monobenzyl ether.

[0073] In the above components (10-4) and (10-6), the term "(mono- or poly)alkylene glycol" refers to a monoalkylene glycol or a polyalkylene glycol. Furthermore, "polyalkylene glycol" refers to a glycol containing 2 to 9 alkylene glycol units.

[0074] (11) Hydrotropes The hydrotropic agent is an organic compound having an anionic group, and examples thereof include alkylbenzenecarboxylic acids or alkylbenzenesulfonic acids or salts thereof containing one or two alkyl groups selected from methyl, ethyl, and propyl and one sulfonic or carboxylic acid group, as well as benzoic acid or its salts. More specifically, examples include paratoluenesulfonic acid, cumenesulfonic acid, metaxylenesulfonic acid, and benzoic acid, and the salts are preferably alkali metal salts.

[0075] (12)Fragrance The perfume has a masking effect and in some cases may be a base material that itself has deodorizing properties. As the fragrance, for example, the fragrances described in "Fundamentals of Fragrance and Fragrance Blending, edited by Nakajima Mototaka, published by Sangyo Tosho Co., Ltd., 4th printing, April 20, 2005" and the fragrances described in JP-A-10-507793 can be used. In addition, the fragrance technology described in JP-A-2014-213072 can be used, and silicate ester fragrances and microcapsule fragrances can also be used.

[0076] <Fiber> The fibers to be treated with the MPF reducing agent for fibers and the fiber treatment composition of the present invention are fibers containing one or more synthetic fibers, and may also contain one or more non-synthetic fibers. The fibers in the present invention may be in the form of threads or test pieces having a predetermined size.

[0077] Examples of synthetic fibers include polyamide fibers (e.g., nylon), polyester fibers (e.g., polyester), polyacrylonitrile fibers (e.g., acrylic), polyvinyl alcohol fibers (e.g., vinylon), polyvinyl chloride fibers (e.g., polyvinyl chloride), polyvinylidene chloride fibers (e.g., vinylidene), polyolefin fibers (e.g., polyethylene, polypropylene), polyurethane fibers (e.g., polyurethane), polyvinyl chloride / polyvinyl alcohol copolymer fibers (e.g., polycrelal), polyalkylene paraoxybenzoate fibers (e.g., benzoate), and polyfluoroethylene fibers (e.g., polytetrafluoroethylene). Other examples include semi-synthetic fibers made by chemically extracting, dissolving, and spinning naturally occurring components, such as protein-based fibers (e.g., milk protein casein fiber, Promix), and cellulose-based fibers (e.g., rayon, Polynosic, cupra, acetate).

[0078] <Textile products> The MPF reducing agent for fibers and the fiber treatment composition of the present invention can also be used to treat textile products. In the present invention, a textile product is, as described above, a product manufactured using fibers. Specifically, it is a fabric such as a woven fabric, a knitted fabric, or a non-woven fabric manufactured using fibers containing one or more synthetic fibers, and products such as undershirts, T-shirts, dress shirts, blouses, slacks, hats, handkerchiefs, towels, knits, socks, underwear, tights, masks, etc. obtained using the same. From the viewpoint of improving the MPF reduction ability, the content of synthetic fibers in the textile product is preferably 5% by mass or more, more preferably 10% by mass or more, still more preferably 20% by mass or more, even more preferably 30% by mass or more, even more preferably 50% by mass or more, and is 100% by mass or less. The content of synthetic fibers in the textile product is even more preferably substantially 100% by mass.

[0079] <MPF Reduction Method> The present invention provides an MPF reduction method in which an MPF reducing agent for fibers composed of a cationic polymer is brought into contact with the fibers.

[0080] In the MPF reduction method of the present invention, the MPF reducing agent for fibers of the present invention can be used by being blended in a detergent composition, a softener composition, a treatment agent composition, or a spray treatment agent composition. Further, the fiber treatment composition of the present invention can be used together with those compositions. Further, the MPF reducing agent for fibers of the present invention can be used as a fiber treatment composition containing a cationic polymer and the above-mentioned optional components as an active ingredient for reducing the amount of MPF. That is, the fiber treatment composition of the present invention is preferably for reducing MPF for fibers and may be an MPF reducing agent composition for fibers. [[ID=?]]

[0081] In the MPF reduction method of the present invention, the cationic polymer and the above-mentioned optional components can apply the above-mentioned preferred embodiments described in the MPF reducing agent for fibers and the fiber treatment composition of the present invention. And the ratio of the content of each component is the same as the preferred embodiment described in the MPF reducing agent for fibers and the fiber treatment composition of the present invention. Further, examples of the fibers include the synthetic fibers contained in the fibers and textile products described in the MPF reducing agent for fibers and the fiber treatment composition. It should be noted that there seems to be a missing number in the tag [[ID=?]] in the original text. If this is an error, please correct it according to the actual situation.

[0082] In the MPF reduction method of the present invention, from the viewpoint of improving the MPF reduction ability, it is preferable to make a fiber treatment composition (hereinafter sometimes referred to as a treatment liquid) by adding a further component and a solvent, preferably water, to the MPF reducer for fibers, and to treat fibers with this to bring the fibers into contact with the MPF reducer for fibers. In the MPF reduction method of the present invention, examples of a method for contacting the MPF reducer for fibers of the present invention with fibers include a method of spraying the treatment liquid onto fibers, a method of applying the treatment liquid onto fibers, and a method of immersing fibers in the treatment liquid.

[0083] When treating fibers with the fiber treatment composition, the concentration of the cationic polymer in the composition (in the treatment solution) is preferably 0.001 ppm or more, more preferably 0.01 ppm or more, even more preferably 0.1 ppm or more, and still more preferably 0.5 ppm or more, from the viewpoint of improving the MPF reduction ability, and is preferably 1,000 ppm or less, more preferably 500 ppm or less, even more preferably 100 ppm or less, and still more preferably 50 ppm or less, from the viewpoint of the fluidity of the fiber treatment composition during treatment.

[0084] The method for reducing MPF of the present invention may be a method for reducing the amount of MPF generated from synthetic fibers when the fibers are fiber washed.

[0085] The method of spraying the treatment liquid onto fibers is preferably a method in which the treatment liquid of the present invention is filled into a sprayer-equipped container and sprayed onto fibers to bring the treatment liquid into contact with the fibers. When applying the treatment liquid to fibers, the treatment liquid may be applied directly to the fibers, or may be brought into contact with the fibers by carrying the treatment liquid on an applicator such as a cloth or brush and applying it to the fibers.

[0086] The treatment solution is preferably prepared by diluting a fiber treatment composition containing, for example, 0.6 to 1.5 mass % of the MPF reducer for fibers of the present invention with water. A specific dilution ratio of the fiber treatment composition of the present invention is preferably 500 times or more, more preferably 800 times or more, from the viewpoint of improving the MPF reduction ability and improving the stability of the fiber treatment composition, and from the same viewpoint, is preferably 5000 times or less, more preferably 3000 times or less. There is no limit to the dilution ratio, and it is preferable to dilute the fiber treatment composition so that the concentration of the cationic polymer in the fiber treatment composition reaches the above-mentioned preferred concentration.

[0087] The pH of the treatment solution at 25° C. is preferably 4 or higher, more preferably 5 or higher, from the viewpoint of improving the MPF reduction ability, and from the same viewpoint, is preferably 12 or lower, more preferably 11 or lower. The pH of the treatment liquid at 25° C. can be measured by the same method as the method for measuring the pH of the blended liquid of the present invention. In this case, the blended liquid of the MPF reducer for fibers or the fiber treatment composition is read as the treatment liquid containing the MPF reducer for fibers or the fiber treatment composition, and the pH of the treatment liquid is measured.

[0088] The hardness of the water used in preparing the treatment solution is, from the viewpoint of improving the MPF reduction ability, preferably 2°dH or more, more preferably 3.5°dH or more, even more preferably 5°dH or more, and even more preferably 7°dH or more on the German hardness scale, and from the same viewpoint, preferably 20°dH or less, more preferably 18°dH or less, and even more preferably 15°dH or less.

[0089] Here, German hardness (°dH) in this specification refers to the concentration of calcium and magnesium in water, expressed as a CaCO3 equivalent concentration of 1 mg / L (ppm) = approximately 0.056°dH (1°dH = 17.8 ppm). The calcium and magnesium concentrations for this German hardness are determined by chelate titration using disodium ethylenediaminetetraacetic acid. The specific method for measuring German water hardness in this specification is described below.

[0090] <Method for measuring water hardness in Germany> 〔reagent〕 0.01 mol / L EDTA·2Na solution: 0.01 mol / L aqueous solution of disodium ethylenediaminetetraacetate (titration solution, 0.01 M EDTA-2Na, manufactured by SIGMA-ALDRICH) ·Universal BT indicator (product name: Universal BT, manufactured by Dojindo Kagaku Kenkyusho Co., Ltd.) Ammonia buffer solution for hardness measurement (67.5 g of ammonium chloride dissolved in 570 mL of 28 w / v% ammonia water, and then made up to 1000 mL with ion-exchanged water) [Measurement of hardness] (1) Use a volumetric pipette to collect 20 mL of sample water into a conical beaker. (2) Add 2 mL of ammonia buffer solution for hardness measurement. (3) Add 0.5 mL of Universal BT indicator. After addition, confirm that the solution is reddish purple. (4) While shaking the conical beaker well, add 0.01 mol / L EDTA·2Na solution dropwise from the buret until the sample water turns blue, which is the end point of the titration. (5) The total hardness is calculated using the following formula. Hardness (°dH)=T×0.01×F×56.0774×100 / A T:0.01mol / L Titration amount of EDTA・2Na solution (mL) A: Sample volume (20 mL, volume of sample water) F: Factor of 0.01 mol / L EDTA·2Na solution

[0091] Furthermore, from the viewpoint of improving the MPF reduction ability, the temperature of the treatment liquid when treating the fibers is preferably 1°C or higher, more preferably 5°C or higher, even more preferably 10°C or higher, and still more preferably 20°C or higher, and from the same viewpoint, it is preferably 60°C or lower, more preferably 50°C or lower, even more preferably 40°C or lower, and still more preferably 30°C or lower.

[0092] In the MPF reduction method for fibers of the present invention, the liquor ratio, which is the ratio of the mass (kg) of the fiber to the amount (L) of the treatment solution, i.e., [amount (L) of treatment solution / mass (kg) of fiber] (hereinafter, this ratio may be referred to as the liquor ratio), is preferably 3 or more, more preferably 10 or more, and even more preferably 12 or more, from the viewpoint of improving the MPF reduction ability, and from the same viewpoint, is preferably 30 or less, more preferably 20 or less, and even more preferably 18 or less.

[0093] In the MPF reduction method of the present invention, the time for treating the fibers is preferably 1 minute or more, more preferably 2 minutes or more, and even more preferably 3 minutes or more, from the viewpoint of improving the MPF reduction ability, and from the same viewpoint, is preferably 5 hours or less, more preferably 3 hours or less, even more preferably 1 hour or less, and even more preferably 30 minutes or less.

[0094] The MPF reduction method of the present invention is also suitable for rotary processing methods. Rotary processing methods refer to processing methods in which fibers or textile products that are not fixed to a rotating device rotate around a rotation axis together with the washing liquid. Rotary processing methods can be carried out using rotary washing machines. Specific examples of rotary washing machines include top-loading washing machines, two-layer washing machines, drum washing machines, pulsator washing machines or agitator washing machines, small washing machines, and automatic loading washing machines. These rotary washing machines can be commercially available for home or industrial use.

[0095] In the MPF reduction method of the present invention, it is preferable to bring fibers into contact with a fiber treatment composition containing a cationic polymer or a treatment liquid containing the composition. Furthermore, the MPF reduction method of the present invention may be a method for reducing MPF in which a cationic polymer is brought into contact with fibers. [Example]

[0096] <Cationic polymer and polymer without cationic group> In the examples and comparative examples, the following cationic polymers and polymers having no cationic groups were used. Polymer 1: A copolymer consisting of a structural unit represented by formula (10) (a, b, and c at the bottom right of [ ] represent 10, 90, and 0.0035, respectively, and these numerical values ​​indicate the content ratio (parts by mole) of each structural unit. d of the crosslinked site is approximately 14, and this numerical value indicates the average number of moles of ethyleneoxy groups at the crosslinked site.) [ka] Polymer 2: 50 / 30 / 20 copolymer of (2-trimethylammonio)ethyl acrylate chloride salt / acrylamide / sodium acrylate salt, manufactured by MT Aquapolymer Co., Ltd., Diaflock KA804E Polymer 3: A copolymer consisting of a structural unit represented by formula (11) (a, b, and c at the bottom right of [ ] represent 10, 90, and 0.01, respectively, and these values ​​represent the content ratio (parts by mole) of each structural unit. d of the crosslinked site is approximately 14, and this value represents the average number of moles of ethyleneoxy groups at the crosslinked site.) [ka] Polymer 4: Poly(2-dimethylamino)ethyl methacrylate, MT Aquapolymer Co., Ltd., Diaflock KP201H Polymer 5: 20 / 80 copolymer of (2-dimethylamino)ethyl acrylate / acrylamide Polymer 6: Cationic hydroxyethyl cellulose (hydroxyethyl cellulose hydroxypropyltrimethylammonium chloride ether) Polymer 7: Poly(N,N-diallyldimethylammonium) chloride Solid content 39-44% by mass, viscosity at 25°C: 8,000 mPa·s to 12,000 mPa·s, manufactured by Lubrizol Polymer 8: Cationic guar gum JAGUAR EXCEL manufactured by Sansho Co., Ltd. Polymer 9: Ethyl sulfate of [2-(ethyldimethylammonio)ethyl] methacrylate / N,N-dimethylacrylamide copolymer Polymer 10: Polyacrylamide Polymer 11: Polyethylene glycol, viscosity 600-800 mPa·s (0.5% aqueous solution, 25°C) Polymers 1 to 7, 9, and 10 are cationic polymers having cationic groups, and their charge densities were calculated by the method described in

[0013] . The weight-average molecular weight of each polymer was calculated in terms of polyethylene glycol by GPC as described in

[0017] .

[0097] [Method of manufacturing polymer 9] A representative copolymer will be described below, and a method for producing polymer 9 will be described below. In a 1 L beaker, 43.03 g of ion-exchanged water, 8.62 g (7.76 g of active ingredient) of MOEDES (dimethylaminoethyl methacrylate quaternized with diethyl sulfate, 90% active ingredient by mass, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.), 22.24 g of DMAAm (N,N-dimethylacrylamide, manufactured by KJ Chemicals Co., Ltd.), and 0.147 g of V-50 (polymerization initiator, 2,2'-azobis(2-amidinopropane) dihydrochloride, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) were mixed and used as monomer aqueous solution A. In a 5 L glass container, 255.14 g of cyclohexane and 100% ethanol as a dispersant were added. TM 0.30 g of Sugar Ester S-770 (manufactured by Mitsubishi Chemical Corporation) was added and dissolved uniformly over 1 hour at 60° C. After dissolution, the solution was cooled to 30° C. to give dispersant solution B. The monomer aqueous solution A was added to the dispersant solution B, which was then placed in a homomixer (ROBOMICS, manufactured by Tokushu Kika Kogyo Co., Ltd.) and stirred at 9000 rpm for 4 minutes to obtain a monomer dispersion with an average particle size of 5 μm. The entire amount was placed in a 500 mL four-neck flask equipped with a stirrer, thermometer, and condenser. After purging with nitrogen, the pressure was reduced to 47.5 kPa and polymerization was carried out at 52°C for 40 minutes. After further aging at 70°C under atmospheric pressure for 1 hour, a dehydration tube equipped with a condenser was attached, and 41 mL of water was removed from the system over approximately 3 hours. As dehydration progressed, the temperature in the tank rose from 78°C to 81°C.

[0098] [Method of manufacturing polymer 1] In the method for producing the polymer 9, polymer 1 was obtained in the same manner as the method for producing the polymer 9, except that 0.0064 g of polyethylene glycol dimethacrylate (manufactured by Shin-Nakamura Chemical Co., Ltd.) was further mixed into the aqueous monomer solution A.

[0099] [Method for Producing Polymer 3] In the method for producing the polymer 9, polymer 3 was obtained in the same manner as the polymer 9, except that 0.018 g of polyethylene glycol dimethacrylate (manufactured by Shin-Nakamura Chemical Co., Ltd.) was further mixed into the aqueous monomer solution A.

[0100] The presence or absence of cationic groups in Polymers 1 to 12 (present: yes, absent: no), the cationic charge density calculated by the above method, the weight average molecular weight (Mw), the storage modulus at 1% strain when dynamic viscoelasticity measurement was carried out at 25°C, a frequency of 1 Hz, and a strain of 0.01% to 1000% for a 1 mass% aqueous solution, and the shear viscosity at 0.005 (1 / s) when dynamic viscoelasticity measurement was carried out at 25°C, a frequency of 1 Hz, and a shear rate of 0.005 to 5000 (1 / s) for a 1 mass% aqueous solution are shown in Table 1.

Table 1

[0101] <Evaluation Method for MPF Reduction Ability> Next, the evaluation method for the MPF reduction ability will be described. Add 0.0125 - 0.075 mL of each 1% polymer aqueous solution to a standard bottle (PS - NO.11 manufactured by AS ONE Corporation), add tap water (Wakayama City water, 25°C) to make a total volume of 25 mL, and put 2 pieces of 6 cm × 6 cm polyester cloth (cut from MITSUWA TIGER semi - fitted round neck SS underwear) into it. Then, cover the standard bottle and shake it in a small constant - temperature shaking incubator (manufactured by TAITEC Corporation, model number: BR - 23FP) at 25°C and 150 rpm for 10 min as a washing process. Subsequently, take out only the cloth and transfer it to a standard bottle filled with 25 mL of Wakayama City water, and perform the same shaking operation for 3 min as a rinsing process. After each process, remove only the cloth from the standard bottle, collect the remaining washing solution, and quantify the MPF discharge amount by the following MPF counting method.

[0102] <Quantification of MPF discharge amount by MPF counting method> (Preparation of measurement sample) Pour all the washing water obtained in the washing process and the rinsing process into a petri dish with the lid removed (AS ONE Corporation's accept petri dish (electron - beam sterilized), diameter 90 mm, height 20 mm). After rinsing the inner wall of the standard bottle with a small amount of tap water, add the rinsing water to the petri dish. At this time, manually remove any large fibers and contaminants that are visibly not MPF using tweezers. Then, gently stir the whole with a dropper or the like to homogenize it so that the MPFs do not overlap, and let it stand for about 1 min until the MPFs sink to the bottom of the petri dish to obtain a measurement sample. (Scan) Scan the above - mentioned measurement sample with a household scanner (Seiko Epson Corporation GT - X830). Scanning conditions: "Professional mode", image type: 48 - Bit color, resolution: 600 dpi, unsharp mask effect "strong" (Counting by image processing) The image file created in (Scan) was read into Image J, and the number of MPFs was counted after the following image processing steps. Evaluation was performed without adding a polymer, and the calculated MPF release rate was set to 100%, and the percentage (%) of MPF release rate for each fiber treatment composition was calculated and used as the MPF release rate (%). The smaller the MPF release rate, the higher the MPF reduction ability of the MPF reducer. The following image processing steps were performed automatically by a computer based on pre-stored settings. 1.Image>Type>8Bit 2.Process>Subtract Background...>Roolingball radius:50pixels(Check Light background) 3. Select the area you want to analyze inside the dish in a circular shape and set the threshold to 245 in Image > Adjust > Threshold. 4. Analyze > Analyze Particles, set the size to "3-Infenity" and output the summary. 5.Get the count value of the output Summary The results are shown in Table 1.

[0103] As is clear from Table 1, it was found that by using the MPF reducer for fibers of the present invention, the amount of MPF emitted can be reduced to 12 to 75%.

Claims

1. It consists of a cationic polymer, The cationic polymer is a microplastic fiber reducing agent for fibers, which has a storage modulus of 4.0 Pa or more at a strain of 1% when a 1% by mass aqueous solution of the cationic polymer is subjected to dynamic viscoelasticity measurement at a strain of 0.01% to 1000% at 25°C and a frequency of 1 Hz.

2. The microplastic fiber reducing agent for fibers according to claim 1, wherein when a 1% by mass aqueous solution of the cationic polymer is subjected to dynamic viscoelasticity measurement at a shear rate of 0.005 to 5000 (1 / s) at 25°C and a frequency of 1 Hz, the cationic polymer has a shear viscosity of 3.0 Pa s or more at 0.005 (1 / s).

3. The microplastic fiber reducing agent for fibers according to claim 1 or 2, wherein the weight average molecular weight of the cationic polymer is 1,000,000 or more.

4. The microplastic fiber reducing agent for fibers according to claim 1 or 2, wherein the charge density of the cationic polymer is +0.1 meq / g or more and +20 meq / g or less.

5. The microplastic fiber reducing agent for fibers according to claim 1 or 2, wherein the cationic polymer comprises a structural unit represented by general formula (1), and one or more structural units selected from a structural unit represented by general formula (2) and a structural unit represented by general formula (4). 【Chemistry 1】 (In the formula, R １ represents a hydrogen atom or a methyl group. ２ , R ３ and R ４ each independently represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms; X represents -O- or -NH-; m represents an integer of 1 to 4; Z － indicates the counter anion.) 【Chemistry 2】 (In the formula, R ５ represents a hydrogen atom or a methyl group. ６ and R ７ each independently represents a hydrogen atom or a hydrocarbon group having 1 to 20 carbon atoms. 【Transformation 3】 (In the formula, R ８ represents a hydrogen atom or a methyl group. ９ represents a hydrogen ion, an alkali metal ion, a (1 / 2) alkaline earth metal ion, an ammonium ion, or an alkylammonium ion having an alkyl group having 1 to 4 carbon atoms.

6. The microplastic fiber reducing agent for fibers according to claim 1 or 2, wherein the cationic polymer contains a crosslinked structural unit represented by general formula (7): 【Chemistry 4】 (In the formula, R ８ indicates the same content as above. １ and X ２ represents —O— or —NH—, respectively. m1 represents an integer of 1 or more and 4 or less. s1 represents a number of 1 or more and 30 or less.

7. A fiber treatment composition containing the microplastic fiber reducing agent for fibers according to claim 1 or 2.

8. A method for reducing microplastic fibers, comprising contacting fibers with the microplastic fiber reducing agent for fibers according to claim 1 or 2.

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