Filament for fishery material

Abstract

Provided is a nylon filament for a fishery material. The filament for a fishery material is biodegradable, has sufficient knot strength in water, and does not readily produce filaments of broken-down monomers when melted. The filament for a fishery material has a filament that includes a nylon resin that has structural units represented by formula (1) and other nylon structural units. The structural units represented by formula (1) are at least 1 mol% but less than 40 mol% of all the structural units of the nylon resin. (In formula (1), x is an integer from 1 to 3.)

Description

Filament for fishery materials

[0001] The present invention relates to a filament for aquatic materials.

[0002] Traditionally, fishing lines have been made of monofilaments such as polyethylene, nylon, and fluorocarbon. Of these, nylon is considered suitable for a variety of fishing styles because it combines flexibility and moderate stretchability with high knot strength.

[0003] Research and development is also being conducted to improve the properties of nylon for fishing line. For example, Patent Document 1 describes that fishing line made from a resin composition in which a copolymer of nylon 6 and nylon 66 (nylon 6 / 66) is blended with polyarylate can adjust the stretchability while also improving the surface lubricity to allow smooth insertion and removal from fishing rod guides. Patent Document 2 also describes the production of a fishing line suitable for crucian carp fishing by adjusting the blend ratio of nylon 6 and nylon 6 / 66.

[0004] JP 2006-122005 A JP 2011-101618 A

[0005] As described in Patent Documents 1 and 2, various nylon fishing lines have been developed and are used for various types of fishing. However, because nylon 6 and nylon 6 / 66 are not biodegradable resins, there are problems with broken fishing lines polluting the environment and ghost fishing for marine life.

[0006] On the other hand, it is thought that the above problems could be solved by using a biodegradable nylon such as nylon 4. However, nylon 4 has the problem of easily absorbing water in water, which can lead to a decrease in knot strength in water. Furthermore, nylon 4 is prone to thermal decomposition, so decomposed monomers are likely to be mixed into the filaments during melt processing, and there is a possibility that the elution of these decomposed monomers could cause environmental pollution. The same problem also exists in fishing nets, which sometimes use nylon filaments.

[0007] The present invention has been made in consideration of the above problems, and its object is to provide a nylon filament for use in fisheries materials that is biodegradable, has sufficient knot strength in water, and reduces the amount of monomer contamination in the filament by suppressing decomposition during melt processing.

[0008] One embodiment of the present invention for solving the above problems relates to a filament for fishery materials according to the following [1] to [9]: [1] A filament for fishery materials having a filament containing a nylon resin having a structural unit represented by the following formula (1) and other nylon structural units, wherein the ratio of the structural unit represented by the following formula (1) to all structural units of the nylon resin is 1 mol % or more and less than 40 mol %. (In formula (1), x is an integer of 1 or more and 3 or less.) [2] The filament for fishery materials according to [1], wherein the nylon resin is a random copolymer in which the structural unit represented by formula (1) and the structural unit of another nylon are randomly arranged. [3] The filament for fishery materials according to [1] or [2], wherein the structural unit represented by formula (1) includes a structural unit in which x is 3. [4] The filament for fishery materials according to any of [1] to [3], wherein the other nylon structural unit includes a nylon 6 structural unit or a nylon 12 structural unit. [5] The filament for fishery materials according to any of [1] to [4], wherein the knot strength measured at 25°C and a relative humidity of 50% is 300 MPa or more. [6] The filament for fishery materials according to any of [1] to [5], wherein the knot strength measured at 25°C after knotting, without removing it from the pure water and drying it, is 100 MPa or more. [7] The filament for fisheries materials according to any one of [1] to [6], which is stored at the interface between seawater and sediment at 25°C for one month, washed with water, dried, and then measured at 25°C and a relative humidity of 50%, and which shows a decrease of 10% or more in knot strength compared to the knot strength measured under the same conditions before storage. [8] The filament for fisheries materials according to any one of [1] to [7], which is a fishing line. [9] The filament for fisheries materials according to any one of [1] to [7], which is a fishing net.

[0009] According to the present invention, there is provided a nylon filament for use in fisheries materials, which is biodegradable, has sufficient knot strength in water, and reduces the amount of monomer contamination in the filament by suppressing decomposition during melt processing.

[0010] One embodiment of the present invention relates to a filament for aquatic materials containing a nylon resin.

[0011] [Nylon Resin] The nylon resin has a structural unit represented by the following formula (1) and other nylon structural units, and the proportion of the structural unit represented by the following formula (1) to all structural units of the nylon resin is 1 mol % or more and less than 40 mol %.

[0012]

[0013] In formula (1), x is an integer of 1 or more and 3 or less. When x is 2 or 3, the alkylene group in formula (1) may be linear or branched.

[0014] The structural unit represented by formula (1) may contain only structural units in which x is the same number, or may contain a plurality of types of structural units in which x is a different number.

[0015] The nylon resin is a copolymer having a structural unit represented by formula (1) and other nylon structural units. The structural unit represented by formula (1) imparts biodegradability to the filament, while the proportion of the structural unit represented by formula (1) within a predetermined range suppresses the decrease in filament strength due to water absorption and increases knot strength in water. These effects are thought to enable filaments containing the nylon to have both biodegradability and sufficient knot strength in water.

[0016] From the viewpoint of achieving a balance between the biodegradability and knot strength in water, the ratio of the structural units represented by formula (1) to all structural units in the nylon resin is set to 1 mol% or more and less than 40 mol%. The higher the ratio of the structural units represented by formula (1), the more likely the filament biodegradability will be improved, and the higher the ratio of other nylon structural units, the more likely the knot strength in water will be increased. From the viewpoint of achieving both of these, the ratio of the structural units represented by formula (1) to all structural units in the nylon resin is preferably 3 mol% or more and 35 mol% or less, more preferably 5 mol% or more and 20 mol% or less, even more preferably 5 mol% or more and 17 mol% or less, and particularly preferably 5 mol% or more and 14 mol% or less.

[0017] From the same viewpoint, the ratio of other nylon structural units to all structural units of the nylon resin is preferably more than 60 mol% and not more than 99 mol%, more preferably 65 mol% or more and 97 mol% or less, even more preferably 80 mol% or more and 95 mol% or less, still more preferably 83 mol% or more and 95 mol% or less, and particularly preferably 86 mol% or more and 95 mol% or less.

[0018] The structural unit represented by formula (1) may be a structural unit derived from glycine where x = 1 (hereinafter also referred to as an "NA2 structural unit"), a structural unit derived from α-alanine (2-aminopropanoic acid), β-alanine (3-aminopropanoic acid) or β-lactam (2-azetidinone) where x = 2 (hereinafter also referred to as an "NA3 structural unit"), or a structural unit derived from γ-aminobutyric acid or 2-pyrrolidone where x = 3 (hereinafter also referred to as an "NA4 structural unit").

[0019] The structural units of the other nylon may be a structural unit represented by formula (2) formed by ring-opening polymerization of a lactam compound or polymerization of an amino acid, or may be a structural unit represented by formula (3) or (4) derived from the diamine and dicarboxylic acid, respectively, when a moiety formed by condensation of a polyamine and a polycarboxylic acid is contained in the nylon resin. The structural units of the other nylon may contain only one of these or may contain a plurality of these.

[0020]

[0021] In formula (2), y is an integer of 4 or more and 11 or less. The alkylene group in formula (2) may be linear or branched.

[0022] When the structural units of other nylons contain structural units represented by formula (2), they may contain only structural units in which y is the same number, or may contain multiple types of structural units in which y is different numbers.

[0023]

[0024] In formula (3), a is an integer of 1 or more and 10 or less. The alkylene group in formula (3) may be linear or branched.

[0025] When the structural units of other nylons contain a structural unit represented by formula (3), they may contain only structural units in which a is the same number, or may contain multiple types of structural units in which a is different numbers.

[0026]

[0027] In formula (4), b is an integer of 1 or more and 12 or less. The alkylene group in formula (4) may be linear or branched.

[0028] When the structural units of other nylons contain a structural unit represented by formula (4), they may contain only structural units in which b is the same number, or may contain multiple types of structural units in which b is different numbers.

[0029] From the viewpoint of enhancing the biodegradability of the molded article, the structural units of the other nylon preferably include structural units represented by formula (2) in which x is 4 or more and 7 or less, more preferably structural units in which y is 5 (hereinafter also referred to as "nylon 6 structural units"), and even more preferably structural units represented by formula (1) are NA4 structural units in which x = 3, and the structural units of the other nylon are NA6 structural units in which y = 5. The ratio of the nylon 6 structural units to the structural units of the other nylon is preferably 50 mol% or more and 100 mol% or less, more preferably 70 mol% or more and 100 mol% or less, and even more preferably 85 mol% or more and 100 mol% or less.

[0030] Alternatively, from the viewpoint of improving the water resistance of the molded article, the structural units of the other nylon preferably include a structural unit represented by formula (2) in which y is 8 or more and 11 or less, more preferably a structural unit in which y is 11 (hereinafter also referred to as a "nylon 12 structural unit"), and even more preferably the structural unit represented by formula (1) is an NA4 structural unit in which x = 3, and the structural unit of the other nylon is an NA12 structural unit in which y = 11. The ratio of the nylon 12 structural unit to the structural units of the other nylon is preferably 50 mol% or more and 100 mol% or less, more preferably 70 mol% or more and 100 mol% or less, and even more preferably 85 mol% or more and 100 mol% or less.

[0031] The structural units derived from the diamine and the dicarboxylic acid may be structural units derived from each of the diamine and the dicarboxylic acid when the nylon resin contains a moiety formed by condensation of a diamine such as hexamethylenediamine, nonanediamine, methylpentadiamine, m-xylylenediamine, p-phenylenediamine, or m-phenylenediamine with a dicarboxylic acid such as adipic acid, sebacic acid, terephthalic acid, or isophthalic acid. In this case, it is more preferable that the structural unit represented by formula (1) is an NA4 structural unit in which x = 3, and the other structural units of nylon are a structural unit represented by formula (3) in which a = 4 and a structural unit represented by formula (4) in which b = 6, which are formed by condensation of hexamethylenediamine and adipic acid.From the viewpoint of improving the heat resistance of the molded article, the proportion of structural units derived from the diamine and the dicarboxylic acid to all structural units of the nylon resin is preferably 50 mol% or more and 100 mol% or less, more preferably 70 mol% or more and 100 mol% or less, and even more preferably 85 mol% or more and 100 mol% or less.

[0032] The nylon resin may be a copolymer consisting only of the structural unit represented by formula (1) and other nylon structural units, or may be a copolymer further containing other structural units. Examples of the other structural units include structural units derived from a polymerization initiator and structural units other than nylon. From the viewpoint of enhancing biodegradability, the ratio of the other structural units to the total structural units of the nylon resin is preferably 0 mol% or more and 50 mol% or less, more preferably 0 mol% or more and 30 mol% or less, and even more preferably 0 mol% or more and 15 mol% or less.

[0033] The structural units of other nylons can reduce the thermal decomposition of the nylon resin. Therefore, the nylon resin, which is a copolymer with the structural units of other nylons, can suppress the inclusion of decomposed monomers (particularly monomers that are raw materials for the structural units represented by formula (1)) during melt processing. Therefore, the nylon resin can suppress environmental pollution caused by the elution of decomposed monomers from molded articles.

[0034] The types and proportions of each structural unit contained in the above nylon resin are as follows: １ H-NMR measurement, or １３ It can be calculated from the integral value of the peaks attributed to each structural unit that appear in the spectrum obtained by C-NMR measurement.

[0035] The nylon resin may be a random copolymer or a block copolymer, but is preferably a random copolymer from the viewpoint of enhancing biodegradability. Whether the nylon resin is a random copolymer or not can be determined by measuring the melting point or glass transition temperature using a differential scanning calorimeter (DSC), infrared absorption spectroscopy (IR spectroscopy), or the like. １３ This can be determined from a spectrum obtained by C-NMR measurement.

[0036] According to the findings of the present inventors, the nylon resin exhibits better biodegradability as the degree of randomness of the structural units increases. In other words, the structural units represented by formula (1) and the structural units of other nylons do not form blocks consisting of only the same structural units in succession as much as possible, and the higher the proportion of different structural units connected adjacently, the higher the biodegradability. From this perspective, the nylon resin is １ The degree of randomness (hereinafter referred to as ")" is calculated from the ratio of each structural unit obtained by H-NMR measurement, assuming that each structural unit is in an ideal random arrangement. １ Also called "H-theory randomness" １３ The degree of randomness (hereinafter referred to as "Ran") is calculated from the ratio of the carbonyl carbon of the amide group linking different structural units to the total peak intensity of the carbonyl carbon, obtained by C-NMR measurement. １３The difference between the randomness (hereinafter also referred to as "randomness difference Δ") and the randomness (hereinafter also referred to as "randomness C") is preferably 0.10 or less, and more preferably 0.05 or less. The lower limit of the randomness difference Δ is not particularly limited, but can be 0.00 or more.

[0037] where １３ The C randomness is a value calculated by the following formula 1: (total peak integral values ​​derived from the carbonyl carbon peaks of the amide groups connecting the first monomer structural unit and the second monomer structural unit) / (total peak integral values ​​derived from all carbonyl carbon peaks).

[0038] １ The H theoretical randomness is the ratio of carbonyl carbons of amide groups connecting different structural units to the total number of carbonyl carbons when all structural units in the nylon resin are stochastically randomly sampled and arranged, １ It is calculated from the proportion of each structural unit obtained by H-NMR measurement using the following formula 2: (proportion of structural units represented by formula (1)) x (proportion of structural units of other nylons) x 2

[0039] The difference Δ in the degree of randomness can be adjusted by the catalyst type, polymerization temperature, etc. For example, by using a Grignard reagent as a catalyst, which increases the reactivity of monomers, the difference in reactivity between monomers can be reduced, thereby reducing the difference Δ in the degree of randomness. Furthermore, if the polymerization temperature is high, monomers that become other structural units of nylon are preferentially consumed, or if the polymerization temperature is low, monomers that become NA4 structural units are preferentially consumed, which tends to result in blocks of these monomers being continuous. Therefore, by setting the polymerization temperature within an appropriate range depending on the combination of monomers, the difference in reactivity between monomers can be reduced, thereby reducing the difference Δ in the degree of randomness.

[0040] ​The nylon resin may be linear or branched. From the viewpoint of improving the formability and strength of the filament, the nylon resin is preferably linear. If a mono- or bi-branched polymerization initiator is used during polymerization, as described below, a linear nylon resin can be obtained.

[0041] From the viewpoint of achieving both biodegradability and the heat resistance and underwater strength of the molded article, the melting point of the nylon resin is preferably 220°C or lower, more preferably 160°C or higher and 215°C or lower, and even more preferably 180°C or higher and 210°C or lower. The melting point of the nylon resin can be measured by DSC. Note that when the difference Δ in the degree of randomness is large (i.e., when blocks of any structural unit are formed), two or more melting points may be observed for the nylon resin by NMR, but it is preferable that only one melting point be observed for the nylon resin by NMR.

[0042] Furthermore, the nylon resin can have a large temperature difference between its melting point and thermal decomposition temperature due to the second monomer structural unit that constitutes the other nylon structures. While nylon 4 homopolymer has a close melting point and thermal decomposition temperature, making it difficult to melt-mold, the nylon resin can be melt-mold easily.

[0043] The weight-average molecular weight (Mw) and number-average molecular weight (Mn) of the nylon resin are not particularly limited. For example, the Mw of the nylon resin may be 10,000 or more, 30,000 or more, or 50,000 or more. The Mw of the nylon resin may be 1,000,000 or less, 500,000 or less, 300,000 or less, 200,000 or less, or 100,000 or less. The Mw of the nylon resin is the Mw calculated as polymethyl methacrylate resin (PMMA) and can be determined by known techniques such as gel permeation chromatography (GPC).

[0044] The polydispersity (Mw / Mn) of the nylon resin is preferably 3.0 or less, more preferably 2.5 or less, and even more preferably 2.0 or less. The lower limit of Mw / Mn is not particularly limited, but can be 1.0 or more. The smaller the Mw / Mn, the less low-molecular-weight oligomers there are, which can prevent changes in properties due to elution of oligomers during use and environmental pollution caused by eluted oligomers. Furthermore, the smaller the Mw / Mn, the higher the mechanical strength of the filament.

[0045] When the nylon resin is a random copolymer, for example, it can be synthesized by ring-opening and copolymerizing a monomer (first monomer) that becomes the structural unit represented by formula (1) with a monomer (second monomer) that becomes another structural unit of nylon in the presence of a basic catalyst and a polymerization initiator.

[0046] Examples of the first monomer that can be used include glycine, α-alanine, β-alanine, β-lactam (2-azetidinone), and 2-pyrrolidone. Examples of the second monomer that can be used include lactam compounds having 5 to 12 carbon atoms, such as δ-valerolactam (2-piperidone), ε-caprolactam, ω-octalactam, and ω-laurolactam, as well as salts of adipic acid and hexamethylenediamine.

[0047] The basic catalyst may be any compound capable of generating anionic species for each monomer. Examples of basic catalysts include Grignard reagents such as ethyl magnesium bromide (EtMgBr), ethyl magnesium chloride (EtMgCl), butyl magnesium chloride (BuMgCl), methyl magnesium chloride (MeMgCl), and methyl magnesium iodide (MeMgI); alkali metals such as lithium, sodium, and potassium, and their hydrides, oxides, hydroxides, carbonates, carboxylates, alkylates, and alkoxides; and alkaline earth metals such as calcium, their hydrides, oxides, hydroxides, carbonates, carboxylates, alkylates, and alkoxides. Examples of alkali metal alkylates include potassium pyrrolidone and potassium tert-butoxide. In this case, potassium pyrrolidone may act as both a monomer and a basic catalyst. Among these, Grignard reagents are preferred because they are required in small amounts, are unlikely to cause environmental pollution due to residues, can be polymerized at relatively low temperatures, and tend to reduce the difference Δ in the degree of randomness.

[0048] The amount (addition amount) of the basic catalyst used is not particularly limited, but is preferably 0.01 mol% to 20 mol% relative to the total amount of raw material monomers, more preferably 0.03 mol% to 15 mol%, and even more preferably 0.05 mol% to 10 mol%. When a Grignard reagent is used, the amount of the basic catalyst used can be 0.05 mol% to 5 mol%, 0.15 mol% to 2.5 mol%, or even 1 mol% to 1.5 mol% relative to the total amount of raw material monomers, from the viewpoint of balancing the reaction rate and catalyst cost.

[0049] Furthermore, a quaternary ammonium salt such as tetramethylammonium chloride, a quaternary phosphonium salt such as tetrabutylphosphonium bromide, a crown ether, or the like may be used in combination as a co-catalyst. By using these in combination, effects such as a reduction in the amount of catalyst, a shortening of the polymerization time, and an improvement in the yield can be expected.

[0050] Examples of polymerization initiators include ester compounds or derivatives thereof, imide compounds, and carbon dioxide. From the viewpoint of improving the moldability of nylon, ester compounds or derivatives thereof, and imide compounds are preferred. The polymerization initiator may be a monobranched compound, or a di- or tri-branched compound. From the viewpoint of achieving both improved processability during molding and improved strength and toughness of molded articles, bi-branched compounds are preferred, and mono-branched compounds are particularly preferred. Examples of mono-branched polymerization initiators include tert-butyl acetate, isopropyl myristate, N-acetyl-ε-caprolactam, 1-acetyl-2-pyrrolidone, and N-benzoyl-2-pyrrolidone. Examples of bi- or tri-branched polymerization initiators include diisopropyl adipate and adipoyldipyrrolidone.

[0051] The amount of the polymerization initiator used (added amount) is not particularly limited, but is preferably 0.01 mol % or more and 1.5 mol % or less, more preferably 0.03 mol % or more and 1.0 mol % or less, even more preferably 0.05 mol % or more and 0.75 mol % or less, and particularly preferably 0.2 mol % or more and 0.3 mol % or less, relative to the total amount of the raw material monomers. If the amount of the polymerization initiator used is within the above range, a high molecular weight nylon resin can be obtained.

[0052] The polymerization temperature can be, for example, 25° C. or higher and 250° C. or lower. In the case of a nylon 4 / 6 copolymer, from the viewpoint of reducing the difference in reactivity between monomers and further reducing the difference Δ in the degree of randomness, the polymerization temperature is preferably 50° C. or higher and 180° C. or lower, and more preferably 80° C. or higher and lower than 150° C.

[0053] The method for synthesizing the nylon resin is not limited to this, and for example, γ-aminobutyric acid (GABA) may be reacted with a lactam compound or ω-aminocarboxylic acid having 5 to 12 carbon atoms.

[0054] [Filament] The filament can be produced by melt-extruding a resin composition containing the nylon resin described above and spinning it into a monofilament.

[0055] In addition to the nylon resin described above, the resin composition may contain other resins, plasticizers, nucleating agents, antioxidants, ultraviolet absorbers, dyes, pigments, heat stabilizers, light stabilizers, fillers, internal mold release agents, matting agents, conductivity-imparting agents, charge control agents, antistatic agents, lubricants, and other known additives such as processing aids.

[0056] In addition, from the viewpoint of enhancing the biodegradability of the filament, the resin composition preferably has a ratio of the above-mentioned nylon resin to the total mass of the resin components of 70% by mass or more and 100% by mass or less, more preferably 90% by mass or more and 100% by mass or less, and even more preferably 95% by mass or more and 100% by mass or less.

[0057] The melt extrusion is preferably carried out at a temperature higher than the melting point of the nylon resin and lower than the thermal decomposition temperature. In this case, by using a resin with a low melting point as the nylon resin, the temperature range in which the melt extrusion is possible can be widened, making molding easier. For example, the melt extrusion can be carried out at a temperature of 180°C or higher and 270°C or lower.

[0058] The resin composition melt-extruded into a fibrous form is preferably cooled in a water bath, the bath temperature of which may be 0°C or higher and 10°C or lower.

[0059] The monofilament thus obtained can be drawn appropriately to obtain a filament. If the drawing ratio is insufficient, the monofilament will not be sufficiently oriented, and the strength required for the fishing line will not be obtained. The conditions for the drawing treatment are not particularly limited, but the drawing ratio can be 4 times or more and 7 times or less. From the viewpoint of improving knot strength, the drawing ratio is preferably 5 times or more and 6 times or less. The drawing may be carried out in multiple stages. Furthermore, a relaxation treatment may be carried out after drawing.

[0060] The diameter of the filament is not particularly limited, and may be, for example, 0.05 mm or more and 4.0 mm or less.

[0061] The filaments thus obtained have high knot strength on land and in water, and also have good biodegradability.

[0062] For example, the knot strength of the filament measured at 25°C and 50% relative humidity can be 100 MPa or more, preferably 300 MPa or more, and more preferably 600 MPa or more. Furthermore, the knot strength of the filament measured at 25°C after knotting, immersed in pure water at 25°C for 3 hours, and then removed from the pure water without drying, can be 100 MPa or more, preferably 300 MPa or more, and more preferably 500 MPa or more. Furthermore, the knot strength of the filament measured at 25°C after knotting, immersed in seawater at 25°C for 3 hours, and then removed from the seawater without drying, can be 100 MPa or more, preferably 300 MPa or more, and more preferably 500 MPa or more. The upper limit of these knot strengths is not particularly limited, but can be 1000 MPa or less.

[0063] The knot strength is a value obtained by dividing the strength at which the knot breaks by the diameter of the filament when a 300 mm long filament having a single knot in the center is used as a test sample, the grip interval is set to 150 mm, and the crosshead speed of the testing machine is set to 150 mm / min.

[0064] The seawater used in the measurements may have a NaCl concentration of 3% or more and 4% or less. The seawater used in the measurements may be seawater actually collected from the ocean, or may be commercially available artificial seawater such as MARINE ART (registered trademark) SF-1 manufactured by Osaka Yaken Co., Ltd.

[0065] Furthermore, after knotting, the filament is stored at 25°C at the interface between seawater and sediment for one month, washed with water, dried, and then measured at 25°C and a relative humidity of 50%. The knot strength of the filament is then reduced by preferably 10% or more, more preferably 20% or more, and even more preferably 30% or more relative to the knot strength measured under the same conditions before storage. On the other hand, from the viewpoint of suppressing a decrease in strength of the filament during use in seawater, the reduction rate is preferably 80% or less, more preferably 70% or less, and even more preferably 60% or less.

[0066] The interface between seawater and sediments refers to the environment within 5 cm from the interface between seawater and sediments as defined in ISO 19679. The sediments may be sea sand collected from the ocean.

[0067] [Filaments for Fisheries Materials] The filaments described above can be used as filaments for fisheries materials such as fishing lines, fishing nets, etc. Filaments for fisheries materials containing the filaments described above have both biodegradability and sufficient knot strength in water.

[0068] [Other Embodiments] It goes without saying that the above-described embodiments are exemplary embodiments of the present invention, and the present invention may include embodiments other than the above-described embodiments within the scope of its core technical concept.

[0069] The present invention will be described in detail based on examples, but the present invention is not limited to these examples.

[0070] 1. Preparation of Filaments Polymers 1 to 9 and polymers 11 to 13 were synthesized by the following method, and filaments 1 to 13 were prepared from these and polymer 10 by the following method.

[0071] 1-1. Preparation of Filament 1 243.8 g (2.86 mol) of 2-pyrrolidone manufactured by Mitsubishi Chemical Corporation and 756.2 g (6.68 mol) of ε-caprolactam manufactured by Tokyo Chemical Industry Co., Ltd. were prepared, mixed, and heated to 80°C to melt, to prepare a homogeneous monomer solution. This monomer solution was divided into two halves, and 8.03 g (0.30 mol % relative to the total moles of 2-pyrrolidone and ε-caprolactam) of separately synthesized adipoyldipyrrolidone was added to one half of the monomer solution and dissolved to prepare an initiator solution. To the other monomer solution, 143.2 ml (1.5 mol % of EtMgBr relative to the total moles of 2-pyrrolidone and ε-caprolactam) of ethyl magnesium bromide (EtMgBr) manufactured by Tokyo Chemical Industry Co., Ltd. in tetrahydrofuran (approximately 1 mol / L) was added dropwise, and then the tetrahydrofuran was removed by distillation under reduced pressure to obtain a catalyst solution. The initiator solution and catalyst solution were mixed and subjected to a polymerization reaction at 100°C to obtain Polymer 1.

[0072] After the polymer was pulverized, it was washed with pure water, an aqueous acetic acid solution, pure water, and pure water in this order to remove unreacted monomers and catalysts, and then dried under reduced pressure to remove water, yielding a polymer powder for spinning.

[0073] The polymer powder obtained above was charged into a small twin-screw extruder, melt-extruded into a fibrous form, and cooled and solidified by passing through a cold bath to produce an undrawn monofilament. This monofilament was then appropriately drawn to obtain filament 1.

[0074] 1-2. Preparation of Filament 2 Polymer 2 was obtained in the same manner as in the synthesis of Polymer 1, except that the polymer materials were changed to 1.38 mol of 2-pyrrolidone and 7.80 mol of ε-caprolactam. A monofilament was prepared from this polymer 2 in the same manner as in the preparation of Filament 1, and the monofilament was subjected to a drawing treatment to prepare Filament 2.

[0075] 1-3. Preparation of Filament 3 Polymer 3 was obtained in the same manner as in the synthesis of Polymer 1, except that the polymer materials were changed to 1.86 mol of 2-pyrrolidone and 7.44 mol of ε-caprolactam, and 0.30 mol % of isopropyl myristate relative to the total moles of 2-pyrrolidone and ε-caprolactam was blended instead of adipoyldipyrrolidone as the initiator. A monofilament was prepared from this polymer 3 in the same manner as in the preparation of Filament 1, and the monofilament was stretched to prepare Filament 3.

[0076] 1-4. Preparation of Filament 4 Polymer 4 was obtained in the same manner as in the synthesis of Polymer 1, except that the polymer materials were changed to 4.03 mol of 2-pyrrolidone and 4.03 mol of ε-caprolactam, 0.20 mol % of N-acetyl-ε-caprolactam was mixed with respect to the total mol of 2-pyrrolidone and ε-caprolactam instead of adipoyldipyrrolidone as the initiator mixed in the initiator solution, the amount of EtMgBr mixed in the catalyst solution was changed to 1.0 mol % with respect to the total mol of 2-pyrrolidone and ε-caprolactam, and the polymerization reaction temperature was changed to 60°C. A monofilament was prepared from this polymer 4 in the same manner as in the preparation of Filament 1, and the monofilament was stretched to prepare Filament 4.

[0077] 1-5. Preparation of Filament 5 Polymer 5 was obtained in the same manner as in the synthesis of Polymer 1, except that the polymer materials were changed to 4.03 mol of 2-pyrrolidone and 4.03 mol of ε-caprolactam, 0.20 mol % of N-acetyl-ε-caprolactam was mixed with respect to the total mol of 2-pyrrolidone and ε-caprolactam instead of adipoyldipyrrolidone as the initiator mixed in the initiator solution, the amount of EtMgBr mixed in the catalyst solution was changed to 1.0 mol % with respect to the total mol of 2-pyrrolidone and ε-caprolactam, and the polymerization reaction temperature was changed to 50°C. A monofilament was prepared from this polymer 5 in the same manner as in the preparation of Filament 1, and the monofilament was stretched to prepare Filament 5.

[0078] 1-6. Preparation of Filament 6 Polymer 6 was obtained in the same manner as in the synthesis of Polymer 1, except that the polymer materials were changed to 24.67 mol of 2-pyrrolidone and 10.58 mol of ε-caprolactam, the amount of adipoyldipyrrolidone incorporated in the initiator solution was changed to 0.25 mol% relative to the total mol of 2-pyrrolidone and ε-caprolactam, tert-butoxy potassium (tBuOK) and tetramethylammonium chloride (TMAC) were incorporated in the catalyst solution instead of EtMgBr, each at 5.0 mol% relative to the total mol of 2-pyrrolidone and ε-caprolactam, and the polymerization reaction temperature was changed to 50°C. A monofilament was prepared from this polymer 6 in the same manner as in the preparation of Filament 1, and the monofilament was stretched to prepare Filament 6.

[0079] 1-7. Preparation of Filament 7 Polymer 7 was obtained in the same manner as in the synthesis of Polymer 6, except that the polymer materials were changed to 8.34 mol of 2-pyrrolidone and 3.41 mol of ε-caprolactam, and 0.20 mol % of tert-butyl acetate relative to the total moles of 2-pyrrolidone and ε-caprolactam was mixed in place of adipoyldipyrrolidone as the initiator mixed in the initiator solution. A monofilament was prepared from this polymer 7 in the same manner as in the preparation of Filament 1, and the monofilament was drawn to prepare Filament 7.

[0080] 1-8. Preparation of Filament 8 Polymer 8 was obtained in the same manner as in the synthesis of Polymer 6, except that the polymer materials were changed to 9.05 mol of 2-pyrrolidone and 2.70 mol of ε-caprolactam, and 0.20 mol % of tert-butyl acetate relative to the total moles of 2-pyrrolidone and ε-caprolactam was mixed in place of adipoyldipyrrolidone as the initiator mixed in the initiator solution. A monofilament was prepared from this polymer 8 in the same manner as in the preparation of Filament 1, and the monofilament was stretched to prepare Filament 8.

[0081] 1-9. Preparation of Filament 9 Polymer 9 was obtained in the same manner as in the synthesis of Polymer 6, except that the polymer materials were changed to 141.00 mol of 2-pyrrolidone and 0.00 mol of ε-caprolactam, and the initiator incorporated in the initiator solution was changed to adipoyldipyrrolidone, with 0.10 mol% tert-butyl acetate incorporated relative to the total mol of 2-pyrrolidone and ε-caprolactam, and the catalyst incorporated in the catalyst solution was changed to EtMgBr, with tert-butoxypotassium (tBuOK) and tetramethylammonium chloride (TMAC), each incorporated at 2.0 mol% relative to the total mol of 2-pyrrolidone and ε-caprolactam, respectively, and the polymerization reaction temperature was changed to 25 ° C. Polymer 9 was obtained in the same manner as in the synthesis of Polymer 6, except that the polymer 9 was used to prepare a monofilament in the same manner as in the preparation of Filament 1, and then stretched to produce Filament 9.

[0082] 1-10. Preparation of filament 10 Commercially available nylon 6 resin (UBE nylon 1022B, manufactured by Ube Industries, Ltd.) was used as polymer 10. This polymer 10 was pulverized to obtain a polymer powder for spinning, and a monofilament was prepared from the obtained polymer powder in the same manner as in the preparation of filament 1. This monofilament was appropriately stretched to obtain filament 10.

[0083] 1-11. Preparation of Filament 11 Polymer 11 was obtained in the same manner as in the synthesis of Polymer 1, except that the polymer materials were changed to 0.95 mol of 2-pyrrolidone and 1.93 mol of ε-caprolactam. A monofilament was prepared from this polymer 11 in the same manner as in the preparation of Filament 1, and the monofilament was subjected to a drawing treatment to prepare Filament 11.

[0084] 1-12. Preparation of Filament 12 Polymer 12 was obtained in the same manner as in the synthesis of Polymer 1, except that the polymer materials were changed to 1.24 mol of 2-pyrrolidone and 1.72 mol of ε-caprolactam. A monofilament was prepared from this polymer 12 in the same manner as in the preparation of Filament 1, and the monofilament was subjected to a drawing treatment to prepare Filament 12.

[0085] 1-13. Preparation of Filament 13 0.95 mol of 2-pyrrolidone manufactured by Mitsubishi Chemical Corporation, 1.77 mol of ε-caprolactam manufactured by Tokyo Chemical Industry Co., Ltd., and 0.35 mol of 12-aminododecanoic acid manufactured by Tokyo Chemical Industry Co., Ltd. were prepared, mixed in an autoclave, and heated to 250°C in a sealed state. After the temperature was raised to 250°C, the pressure release valve of the autoclave was opened to return the pressure to atmospheric pressure, and the valve was closed again to carry out a polymerization reaction at 250°C, thereby obtaining Polymer 13. A monofilament was prepared from this Polymer 13 in the same manner as in the preparation of Filament 1, and the monofilament was stretched to produce Filament 13.

[0086] The polymerization conditions for polymers 1 to 13 used in the production of filaments 1 to 13 are shown in Table 1. Note that "NA4 / 6" for polymer type indicates nylon 4 / 6, "NA4" for nylon 4, and "NA6" for nylon 6, respectively. The amounts of initiator and catalyst added are the amounts blended relative to the total moles of monomers, while the monomer "pyrrolidone" indicates the amount of 2-pyrrolidone, and "caprolactam" indicates the amount of ε-caprolactam.

[0087]

[0088] 2. Measurement Polymers 1 to 13 were measured using the following method. １ H-NMR, １３ Measurements by C-NMR, DSC, and TGA, and biodegradability (O ２ The filaments 1 to 13 were subjected to GPC analysis by the following method.

[0089] 2-1. １ H-NMR measurement: Using a nuclear magnetic resonance spectrometer (JASCO Corporation, JNM-ECZ600R / S1) １H-NMR spectra were obtained and compared. Specifically, 10 mg of each polymer sample was dissolved in 1 ml of trifluoroethanol (TFE) / d2 chloroform (CDCl ３ The sample was dissolved in a mixed solvent of 1 / 1 by volume of tetramethylsilane (TMS). Measurement was then performed using tetramethylsilane (TMS) as the standard. Of the peaks derived from methylene groups appearing between 1.0 ppm and 2.0 ppm in the obtained spectrum, the ratio of the integral value of the peak of methylene protons derived from nylon 4 structural units to the integral value of the peak of methylene protons derived from nylon 6 units was determined. From the ratio of the integral values ​​of these peaks, the ratio of nylon 4 structural units was calculated, and this was designated the "NA4 ratio."

[0090] In addition, from this NA4 ratio and the ratio of nylon 6 structural units (NA6 ratio) produced at the same time, the degree of randomness ((NA4 ratio) x (NA6 ratio) x 2) was calculated assuming that each polymer was an ideal random arrangement of nylon 4 structural units and nylon 6 structural units. １ H theory randomness.

[0091] 2-2. １３ C-NMR measurement: Using a nuclear magnetic resonance spectrometer (JASCO Corporation, JNM-ECZ600R / S1) １３ Specifically, 10 mg of each polymer sample was dissolved in 1 ml of trifluoroethanol (TFE) / d2 chloroform (CDCl ３ The nylon 4 structural unit and nylon 6 structural unit were dissolved in a mixed solvent of nylon 6 and nylon 4 structural units in a volume ratio of 1 / 1. Measurement was then carried out using tetramethylsilane (TMS) as the standard. The ratio of the peak intensity of the carbonyl carbon of the amide group linking the nylon 4 structural unit and the nylon 6 structural unit to the total peak intensity of all peaks originating from carbonyl carbons appearing between 174 ppm and 177 ppm in the obtained spectrum was calculated, and this was referred to as " １３ C randomness".

[0092] 2-3. DSC Measurement Differential scanning calorimeter (Mettler Toledo, DSC3 ＋DSC curves were obtained by differential scanning calorimetry (DSC) using a 10 mg sample of each polymer. Specifically, 10 mg of a sample was weighed into an aluminum pan and heated at a rate of 20°C / min in a nitrogen atmosphere within the range of 25°C to 280°C to obtain a DSC curve. The peak top temperature of the endothermic peak based on the melting behavior in this DSC curve was taken as the "melting point" of each polymer.

[0093] 2-4. TGA Measurement A thermogravimetric / differential thermal simultaneous analyzer (TGA / DSC2, manufactured by Mettler Toledo) was used to obtain a thermogravimetric / differential thermal simultaneous analyzer. Specifically, a 10 mg sample of each polymer was weighed into an aluminum pan and heated at a rate of 20°C / min in a nitrogen atmosphere within the range of 25°C to 500°C to obtain a thermogravimetric / differential thermal simultaneous analyzer. The temperature at which 5% weight loss occurred in this thermogravimetric / differential thermal simultaneous analyzer was determined as the "5% thermogravimetric / differential thermal simultaneous analyzer temperature" for each polymer.

[0094] 2-5. GPC Analysis GPC analysis was performed using a gel permeation chromatography (GPC) analyzer (HLC-8420GPC, manufactured by Tosoh Corporation). Specifically, 10 mg of sample for each filament was dissolved in hexafluoroisopropanol (HFIP) containing sodium trifluoroacetate dissolved at a concentration of 5 mM to obtain a 10 mL solution, which was then filtered through a membrane filter to obtain a sample solution. 100 μL of this sample solution was injected into the analyzer, and measurements were carried out under the following conditions. From the chromatogram obtained by the measurement, the weight average molecular weight (Mw) and number average molecular weight (Mn) of the polymer constituting each filament were calculated using a calibration curve obtained with polymethyl methacrylate resin (PMMA) of known molecular weight. Apparatus: HLC-8420GPC, manufactured by Tosoh Corporation Column: HFIP 806M x 2 in series, 40°C Eluent: 5 mM CF ３ COONa / HFIP Flow rate: 1.0 mL / min Detector: differential refractometer (RI)

[0095] 2-6. Biodegradable (O ２(Reference) 2000 g of sediment collected from the Pacific coast was added to 4000 ml of seawater collected from the Pacific coast, and microorganisms in the sediment were extracted into seawater by ultrasonic treatment. Nutrient salts, 0.5 g / L of ammonium chloride and 0.1 g / L of potassium dihydrogen phosphate, were dissolved in the extracted seawater, followed by aeration to prepare extracted seawater. Approximately 40 mg of polymer powder was dispersed in 300 ml of the prepared extracted seawater, and the pressure change caused by capturing the generated carbon dioxide with sodium hydroxide in a sealed environment was measured for 4 weeks using a BOD meter (OxiTop i, manufactured by WTW). The biodegradability of the polymer powder was evaluated using the following formula, where the theoretical value is the amount of oxygen required for 100% decomposition of the polymer: Biodegradability (%) = (oxygen consumption from sample / theoretical oxygen demand) x 100

[0096] Tables 2 and 3 show the NA4 ratios of Polymer 1 to Polymer 13 and Filament 1 to Filament 13. １ H-theory randomness, １３ C randomness, １ H-theory randomness and １３ C difference Δ from the randomness, melting point, 5% thermal weight loss temperature, difference ΔT between the melting point and 5% thermal weight loss temperature, weight average molecular weight Mw, number average molecular weight Mn, Mw / Mn, NA4 ratio of each polymer on a mass basis converted from the molar ratio of NA4, O ２ The biodegradability evaluated according to the standard and the stretching ratio are shown.

[0097]

[0098]

[0099] 3. Evaluation 3-1. Strength The knot strength of Filaments 1 to 13 was measured in an indoor environment, an underwater environment, and a biodegradable environment by the following method.

[0100] The knot strengths were measured in a room environment, an underwater environment, and a biodegradable environment using a tensile tester (Tensilon RTF-1210, manufactured by A&D Co., Ltd.). Specifically, a filament having a length (grip distance) of 300 mm and a single knot in the center was used as a test sample. The crosshead speed of the tester was set to 150 mm / min, and the load at which the knot broke was divided by the filament diameter to obtain the knot strength in each environment.

[0101] The environmental conditions were as follows: Indoor environment: Measurements were made at 25°C and a relative humidity of 50% Underwater environment: After immersion in pure water at 25°C for 3 hours, the samples were nodulated without drying and then measured at 25°C Biodegradation environment: After nodulation, the samples were stored at the interface between seawater and sediment at 25°C for 1 month, and then measured at 25°C and a relative humidity of 50% Note that the seawater and sediment used were seawater (NaCl concentration: 3.1-3.4%) collected from the Pacific coast and sea sand, respectively.

[0102] Furthermore, the difference between the knot strength in the indoor environment and the knot strength in the biodegradable environment was calculated, and the ratio of this difference to the knot strength in the indoor environment ((knot strength in the indoor environment - knot strength in the biodegradable environment) / knot strength in the indoor environment x 100) was calculated to obtain the "strength reduction rate after biodegradation." A strength reduction rate of 10% or more in the biodegradable environment was determined to be "biodegradable (strength standard)."

[0103] Table 4 shows the knot strength, strength loss rate after biodegradation, and biodegradability evaluation results for Filaments 1 to 13 in each of the indoor environment, underwater environment, and biodegradation environment. Filaments 6 to 8 were significantly embrittled in water and were unable to maintain their shape as fishing lines. Therefore, it was not possible to measure the knot strength in underwater and biodegradation environments.

[0104] 3-2. First Monomer Content Approximately 100 mg of sample was dissolved in 10 ml of HFIP, and then acetone was added to make the total volume 50 ml. The precipitated polymer was removed using a 20 μm membrane filter, and the filtrate was measured. Measurement device: GC-2010 Plus manufactured by Shimadzu Corporation Column: Rix15MS (0.25 mmφ-15 m-0.25 μm df) manufactured by Resteke Corporation Column temperature: 50°C - 5 min → (20°C / min) → 250°C Vaporization chamber temperature: 250°C Detector: FID Split ratio: 50 Injection amount: 1 μl Make-up gas: He Gas flow rate: 30 ml / min

[0105] Table 4 shows the knot strength of Filaments 1 to 13 in an indoor environment, an underwater environment, and a biodegradation environment, the percentage decrease in strength after biodegradation, the results of the biodegradability evaluation based on the percentage decrease in strength, and the content of 2-pyrrolidone.

[0106]

[0107] As shown in Tables 1 to 4, filaments 1 to 5 and filaments 11 to 13 made from polymers 1 to 5, which are nylon resins having structural units represented by formula (1) and other nylon structural units, and in which the proportion of structural units represented by formula (1) to all structural units is 1 mol % or more but less than 40 mol %, were biodegradable and less brittle in water, making them fully usable as fishing lines and fishing nets. Furthermore, filaments 1 to 5 and filaments 11 to 13 had strengths comparable to nylon 6 (filament 10), which is conventionally used for fishing lines.

[0108] This application claims priority to Japanese Patent Application No. 2022-158909, filed September 30, 2022, and Japanese Patent Application No. 2023-074576, filed April 28, 2023. The entire disclosures and claims of those applications are incorporated herein by reference.

[0109] The filaments for fishery materials according to the present invention have sufficient knot strength even in water and are biodegradable, so the present invention is expected to contribute to reducing environmental pollution caused by broken fishing lines.

Claims

1. The present invention has filaments containing a nylon resin having a structural unit represented by the following formula (1) and other nylon structural units, The nylon resin has a ratio of the structural unit represented by the following formula (1) to all structural units of 1 mol % or more and less than 40 mol %: Filament for fisheries materials. 【Chemistry 1】 (In formula (1), x is 3.)

2. The nylon resin is a random copolymer in which the structural unit represented by the formula (1) and the structural units of the other nylons are randomly arranged. The filament for marine materials according to claim 1.

3. The structural units of the other nylons include nylon 6 structural units, nylon 12 structural units, or nylon 66 structural units. The filament for marine materials according to claim 1 or 2.

4. The knot strength measured at 25°C and 50% relative humidity is 300 MPa or more. The filament for marine materials according to claim 1 or 2.

5. The knot strength measured after immersing in pure water at 25°C for 3 hours and then knotting at 25°C without removing from the pure water and drying is 100 MPa or more. The filament for marine materials according to claim 1 or 2.

6. The knot strength measured at 25°C and 50% relative humidity after storing the sample at the interface between seawater and sediment for one month at 25°C, rinsing with water and drying is 10% or more lower than the knot strength measured under the same conditions before storage. The filament for marine materials according to claim 1 or 2.

7. The filament for fishery materials according to claim 1 or 2, which is a fishing line.

8. The filament for fishery materials according to claim 1 or 2, which is a fishing net.

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