JP2022082177A - Fiber, molding, method for disposing of fiber, and method for disposing of molding - Google Patents

Abstract

To provide a fiber using a polyamide resin and having excellent biodegradability and high strength, a molding, a method for disposing of the fiber, and a method for disposing of the molding.SOLUTION: The fiber contains a polyamide resin and a cobalt salt. The polyamide resin contains a xylylenediamine-based polyamide resin containing a diamine-derived constituent unit and a dicarboxylic acid-derived constituent unit, wherein 50 mol% or more of the diamine-derived constituent unit is derived from xylylenediamine and 50 mol% or more of the dicarboxylic acid-derived constituent unit is derived from a C8-22 α,ω-linear aliphatic dicarboxylic acid.SELECTED DRAWING: None

Description

The present invention relates to a fiber, a molded body, a method for disposing of the fiber, and a method for disposing of the molded body. In particular, the present invention relates to fibers having excellent biodegradability using a polyamide resin and the like.

Conventionally, it has been studied to use a polyamide resin for a fiber.
For example, Patent Document 1 describes a monofilament containing a polyamide resin, which is a unit derived from ε-caprolactam and / or ε-aminocaproic acid (hereinafter, also referred to as “unit 1”), adipic acid. A unit derived from an acid (hereinafter, also referred to as “unit 2”) and a unit derived from hexamethylenediamine (hereinafter, also referred to as “unit 3”) are included, and unit 1, unit 2 and unit 3 are included. The monofilament in which the unit 1 is more than 60% by mass and less than 80% by mass is disclosed.
Further, Patent Document 2 discloses a polyamide filament containing a polyamide resin obtained by polycondensing an aliphatic diamine containing pentamethylenediamine as a main component and a dicarboxylic acid containing adipic acid as a main component. ..

Japanese Unexamined Patent Publication No. 2016-22303 Japanese Unexamined Patent Publication No. 2010-281827

As described above, although polyamide resins are used for fibers (filaments), polyamide resin fibers having biodegradability are required as part of recent efforts for environmental protection. However, even if the biodegradation performance is excellent, the practicality is low if the strength is inferior.
The present invention aims to solve such a problem, and is a fiber using a polyamide resin, which is excellent in biodegradability and has high strength, a fiber, a molded body, a method for disposing of the fiber, and a method for disposing of the fiber. It is an object of the present invention to provide a method of disposing of a molded body.

As a result of studies by the present inventor based on the above problems, it has been found that the above problems can be solved by using a predetermined xylylenediamine-based polyamide resin as a raw material for fibers and blending a cobalt salt. I found it.
Specifically, the above problem was solved by the following means.
<1> Containing polyamide resin and cobalt salt,
The polyamide resin contains a diamine-derived structural unit and a dicarboxylic acid-derived structural unit, and 50 mol% or more of the diamine-derived structural unit is derived from xylylene diamine and 50 mol% of the dicarboxylic acid-derived structural unit. The above is a fiber containing a xylylene diamine-based polyamide resin derived from an α, ω-linear aliphatic dicarboxylic acid having 8 to 22 carbon atoms.
<2> The fiber according to <1>, wherein the mass ratio of the xylylenediamine structure in the xylylenediamine-based polyamide resin is 20 to 70% by mass; where the mass ratio of the xylylenediamine structure is defined as [2>. It is a value calculated from (mass of xylylenediamine structure in polyamide resin) / (mass of total polyamide resin)] × 100.
<3> The above-mentioned <1> or <2>, wherein the α, ω-linear aliphatic dicarboxylic acid having 8 to 22 carbon atoms contains an α, ω-linear aliphatic dicarboxylic acid having 11 to 22 carbon atoms. Fiber.
<4> The fiber according to <1> or <2>, wherein the α, ω-linear aliphatic dicarboxylic acid having 8 to 22 carbon atoms contains 1,12-dodecanedioic acid.
<5> The fiber according to any one of <1> to <4>, wherein the cobalt salt contains a carboxylic acid salt of cobalt.
<6> The fiber according to any one of <1> to <4>, wherein the cobalt salt contains cobalt stearate.
<7> Described in any one of <1> to <6>, wherein the content of the cobalt atom in the cobalt salt is 10 to 2000 mass ppm with respect to 100 parts by mass of the xylylenediamine-based polyamide resin. Fiber.
<8> The fiber according to any one of <1> to <7>, which is biodegradable.
<9> One of <1> to <8> having a biodegradation degree of 10% or more after storing the fiber in a compost environment at 58 ± 2 ° C. and 100% relative humidity for 90 days. Described fiber: Here, the degree of biodegradation (%) is [(total CO ₂ generation amount during storage for 90 days in a compost environment) / (theoretical carbon dioxide generation amount calculated from the composition formula)] × 100. be.
<10> A molded body formed from the fiber according to any one of <1> to <9>.
<11> The molded body according to <10>, wherein the molded body is a fishing net.
<12> A method for disposing of fibers, which comprises biodegrading the fibers according to any one of <1> to <9>.
<13> A method for disposing of a molded product, which comprises biodegrading the molded product according to <10> or <11>.

INDUSTRIAL APPLICABILITY According to the present invention, it has become possible to provide a fiber using a polyamide resin, which has excellent biodegradability and high strength, a fiber, a molded body, a method for disposing of the fiber, and a method for disposing of the molded body.

Hereinafter, embodiments for carrying out the present invention (hereinafter, simply referred to as “the present embodiment”) will be described in detail. The following embodiments are examples for explaining the present invention, and the present invention is not limited to the present embodiment.
In addition, in this specification, "-" is used in the meaning which includes the numerical values described before and after it as the lower limit value and the upper limit value.
In the present specification, various physical property values and characteristic values shall be at 23 ° C. unless otherwise specified.
As used herein, ppm means mass ppm.

The fiber of the present embodiment contains a polyamide resin and a cobalt salt, and the polyamide resin contains a diamine-derived structural unit and a dicarboxylic acid-derived structural unit, and 50 mol% or more of the diamine-derived structural unit is xylylene diamine. It is characterized in that 50 mol% or more of the constituent unit derived from the dicarboxylic acid contains a xylylene diamine-based polyamide resin derived from an α, ω-linear aliphatic dicarboxylic acid having 8 to 22 carbon atoms.
With such a configuration, fibers having excellent biodegradability and high strength can be obtained. The reason for this is presumed to be as follows.
In order to biodegrade the resin, for example, when it is left in a compost environment for a long period of time, microorganisms act on the resin to reduce the molecular weight of the resin. As a result, microorganisms are more likely to penetrate into the resin, biodegradation proceeds, and decompositions into oligomers, monomers, and even smaller molecules. However, since the polyamide resin generally has a strong amide bond and is usually a crystalline resin, it is not easily affected by microorganisms and its molecular weight is unlikely to decrease. Therefore, the polyamide resin is less likely to be decomposed by microorganisms. In the present embodiment, by using a predetermined xylylenediamine-based polyamide resin as the polyamide resin, the NH ₂ -CH ₂ -benzene ring moiety of the xylylenediamine is oxidatively decomposed by cobalt, and the benzyl moiety and NH ₂ are oxidatively decomposed. It was speculated that it would be cut off between. As a result, it is presumed that the decrease in the molecular weight of the xylylenediamine-based polyamide resin was promoted and the biodegradation could be promoted. Further, the fiber of the present embodiment maintains the strength inherent in the polyamide resin fiber as well as the strength before biodegradation.
Hereinafter, the details of the fiber of the present embodiment will be described.

<Polyamide resin>
The fiber of this embodiment contains a xylylenediamine-based polyamide resin. The xylylene diamine-based polyamide resin in the present embodiment contains a diamine-derived structural unit and a dicarboxylic acid-derived structural unit, and 50 mol% or more of the diamine-derived structural unit is derived from the xylylene diamine and the dicarboxylic acid. More than 50 mol% of the derived constituent unit is a polyamide resin derived from an α, ω-linear aliphatic dicarboxylic acid having 8 to 22 carbon atoms. By using such a xylylenediamine-based polyamide resin and further adding a cobalt salt, a fiber having excellent biodegradability can be obtained while maintaining the original strength of the fiber.

In the xylylenediamine-based polyamide resin, 50 mol% or more of the constituent unit derived from diamine is derived from xylylenediamine, but it is preferably 70 mol% or more, and more preferably 90 mol% or more. , 95 mol% or more, more preferably 99 mol% or more. The upper limit may be 100 mol%.

The xylylenediamine preferably contains 0-100 mol% metaxylylenediamine and 0-100 mol% paraxylylenediamine, with 0-90 mol% metaxylylenediamine and 10-100 mol% para. It is more preferable to contain xylylenediamine, and even more preferably to contain 0 to 80 mol% of metaxylylenediamine and 20 to 100 mol% of paraxylylenediamine. The inclusion of paraxylylenediamine tends to further improve biodegradability. Further, in the xylylenediamine, the total of the metaxylylenediamine and the paraxylylenediamine preferably occupies 95 mol% or more, more preferably 99 mol% or more, still more preferably 100 mol%.

Diamine components other than xylylenediamine include tetramethylenediamine, pentamethylenediamine, 2-methylpentanediamine, hexamethylenediamine, heptamethylenediamine, octamethylenediamine, nonamethylenediamine, decamethylenediamine, dodecamethylenediamine, 2, Aliphatic diamines such as 2,4-trimethyl-hexamethylenediamine and 2,4,4-trimethylhexamethylenediamine, 1,3-bis (aminomethyl) cyclohexane, 1,4-bis (aminomethyl) cyclohexane, 1, 3-Diaminocyclohexane, 1,4-diaminocyclohexane, bis (4-aminocyclohexyl) methane, 2,2-bis (4-aminocyclohexyl) propane, bis (aminomethyl) decalin, bis (aminomethyl) tricyclodecane, etc. Examples of diamines having an aromatic ring such as alicyclic diamine, bis (4-aminophenyl) ether, paraphenylenediamine, and bis (aminomethyl) naphthalene can be exemplified. Can be used.

In the xylylene diamine-based polyamide resin, the constituent unit derived from the dicarboxylic acid is 70 mol% or more, although 50 mol% or more is derived from the α, ω-linear aliphatic dicarboxylic acid having 8 to 22 carbon atoms. It is preferably 90 mol% or more, more preferably 95 mol% or more, still more preferably 99 mol% or more. The upper limit may be 100 mol%.
The number of carbon atoms in the α, ω-linear aliphatic dicarboxylic acid having 8 to 22 carbon atoms is preferably 10 or more, more preferably 11 or more, and even more preferably 12 or more. By setting the value to the lower limit or higher, it tends to be more susceptible to biodegradation by microorganisms. Further, the number of carbon atoms in the α, ω-linear aliphatic dicarboxylic acid having 8 to 22 carbon atoms is preferably 21 or less, and preferably 20 or less. By setting the value to the upper limit or less, the hydrophilicity is improved and it tends to be more susceptible to decomposition by microorganisms. The number of carbon atoms in the α, ω-linear aliphatic dicarboxylic acid having 8 to 22 carbon atoms is preferably 10 or 12, and more preferably 12.
Specific examples of the α, ω-linear aliphatic dicarboxylic acid having 8 to 22 carbon atoms include suberic acid, azelaic acid, sebacic acid, 1,11-undecanedioic acid, 1,12-dodecanedioic acid, and 1,. 13-Tridecaneic acid, 1,14-tetradecanedioic acid, 1,15-pentadecanedioic acid, 1,16-hexadecanedioic acid, 1,17-heptadecaneic acid, 1,18-octadecanoic acid, 1,19-nonadecannic acid , 1,20-Eicosandioic acid, 1,21-heneichosandioic acid, 1,22-docosanedioic acid, eg, sebacic acid, 1,12-dodecanedioic acid, 1,14-tetradecanedioic acid, 1,16. -Hexadecanoic acid, 1,18-octadecanoic acid, 1,20-eicosandioic acid, 1,21-heneicosanedioic acid, 1,22-docosanedioic acid, 1,14-tetradecanedioic acid, 1,16-hexadecane More preferred are diic acid, 1,18-octadecanedioic acid, eicosandioic acid and docosanedioic acid. When the α, ω-linear aliphatic dicarboxylic acid having 8 to 22 carbon atoms is 1,12-dodecanedioic acid, the above effect is particularly remarkable.

Examples of the dicarboxylic acid component other than the α, ω-linear aliphatic dicarboxylic acid having 8 to 22 carbon atoms include α, ω-linear aliphatic dicarboxylic acid having 7 or less carbon atoms such as adipic acid, isophthalic acid, and terephthalic acid. A phthalic acid compound such as orthophthalic acid, 1,2-naphthalenedicarboxylic acid, 1,3-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, 1,6-naphthalenedicarboxylic acid, 1, Examples of naphthalenedicarboxylic acids such as 7-naphthalenedicarboxylic acid, 1,8-naphthalenedicarboxylic acid, 2,3-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, and 2,7-naphthalenedicarboxylic acid can be exemplified. Seeds or a mixture of two or more can be used.

In addition, "including a structural unit derived from a diamine and a structural unit derived from a dicarboxylic acid" means that at least a part of the amide bonds constituting the xylylene diamine-based polyamide resin is formed by the bond between the dicarboxylic acid and the diamine. Further, in addition to the constituent unit derived from a dicarboxylic acid and the constituent unit derived from a diamine, other sites such as a terminal group may be included. In addition, repeating units having an amide bond not derived from the bond between the dicarboxylic acid and the diamine, a trace amount of impurities, and the like may be contained. Specifically, the xylylene diamine-based polyamide resin contains ε-caprolactam and lauro as components constituting the xylylene diamine-based polyamide resin in addition to the diamine component and the dicarboxylic acid component, as long as the effects of the present embodiment are not impaired. Lactams such as lactam and aliphatic aminocarboxylic acids such as aminocaproic acid and aminoundecanoic acid can also be used as the copolymerization component. In the present embodiment, the xylylenediamine-based polyamide resin is preferably 90% by mass or more, more preferably 95% by mass or more, still more preferably 98% by mass or more with a diamine-derived structural unit or a dicarboxylic acid-derived structural unit. be.

The polyamide resin used in this embodiment preferably has a xylylenediamine structure having a mass ratio of 20 to 70% by mass. With such a configuration, it is possible to reduce the molecular weight of the resin and improve the biodegradability of the decomposition product in a well-balanced manner. Here, the mass ratio of the xylylenediamine structure is a value calculated from [(mass of the xylylenediamine structure in the polyamide resin) / (mass of the entire polyamide resin)] × 100. The xylylenediamine structure refers to a portion represented by "-HN-CH ₂ -benzene ring-CH ₂ -NH-".
The lower limit of the mass ratio of the xylylenediamine structure is preferably 25% by mass or more, more preferably 28% by mass or more, further preferably 30% by mass or more, and further preferably 35% by mass. It may be the above, and in particular, it may be 40% by mass or more. By setting the value to the lower limit or higher, the starting point of decomposition increases, and low molecular weight components that are more susceptible to biodegradation tend to be easily generated. The upper limit of the mass ratio of the xylylenediamine structure is preferably 60% by mass or less, more preferably 55% by mass or less, further preferably 50% by mass or less, and 48% by mass. The following is more preferable. By setting the value to the upper limit or less, the xylene skeleton that is less susceptible to biodegradation tends to decrease, and the degree of biodegradation of the resin as a whole tends to be further improved.

The content of the xylylenediamine-based polyamide resin in the fiber of the present embodiment is preferably 80% by mass or more, more preferably 85% by mass or more, and further preferably 90% by mass or more in the fiber. It is more preferably 95% by mass or more, and even more preferably 99% by mass or more. By setting the value to the lower limit or higher, the strength of the fiber is more effectively achieved. The upper limit is the amount of the xylylenediamine-based polyamide resin in which all the components other than the cobalt salt are formed.
The fiber of the present embodiment may contain only one kind of xylylenediamine-based polyamide resin, or may contain two or more kinds. When two or more kinds are contained, it is preferable that the total amount is within the above range.

The fiber of the present embodiment may or may not contain a polyamide resin other than the xylylenediamine-based polyamide resin.
Examples of the other polyamide resin include one or more types such as an aliphatic polyamide resin, an alicyclic polyamide resin, and a semi-aromatic polyamide resin, and an aliphatic polyamide resin and an alicyclic polyamide resin are preferable. Group polyamide resins are more preferred.
Specific examples of the other polyamide resin include polyamide 4, polyamide 6, polyamide 11, polyamide 12, polyamide 46, polyamide 66, polyamide 6/66, polyamide 610, polyamide 612, polyamide 6T, polyamide 6 / 6T, and polyamide. 66 / 6T, Polyamide 6I, Polyamide 66 / 6I / 6, Polyamide 66 / 6I, Polyamide 6T / 6I, Polyamide 6T / 12, Polyamide 66 / 6T / 6I, Polyamide 9T, Polyamide 9I, Polyamide 9T, 9I, Polyamide 10T, 1,3-BAC10I (polyamide resin composed of 1,3-bisaminomethylcyclohexane, sebacic acid and isophthalic acid), 1,4-BAC10I (polyamide resin composed of 1,4-bisaminomethylcyclohexane, sebacic acid and isophthalic acid) Polyamide resin), and polyamide 6 and / or polyamide 66 are preferred.
When these other polyamide resins are contained, the content thereof is preferably 5 to 15% by mass in the fiber.

<Cobalt salt>
The fiber of this embodiment contains a cobalt salt. By containing a cobalt salt, biodegradation is promoted when the fiber of the present embodiment is placed in a compost environment or the like. In particular, since the cobalt salt has almost no adverse effect on the xylylenediamine-based polyamide resin before it is placed in a compost environment, it impairs the inherent performance (particularly strength) of the fiber when it is used. It is preferable because it is difficult.
The type of cobalt salt is not particularly limited and may be either a divalent salt or a trivalent salt, but a divalent salt is preferable.
The cobalt salt is preferably a cobalt carboxylate. By using the carboxylate, the reduction in molecular weight due to the oxidative decomposition of the benzyl position tends to be promoted more effectively.
In the case of cobalt carboxylic acid salts, the carboxylic acid is preferably an aliphatic carboxylic acid. The aliphatic carboxylic acid is not particularly specified because it does not significantly affect the oxidative decomposition behavior of the resin by cobalt, but either a linear or branched aliphatic carboxylic acid can be preferably adopted, and a linear fat can be used. More preferably, it is a group carboxylic acid. The carbon number of the aliphatic carboxylic acid is not particularly determined because it does not significantly affect the oxidative decomposition behavior of the resin by cobalt, but it is preferably 2 or more, and may be 10 or more, and may be 10 or more. It is preferably 40 or less, more preferably 30 or less, and even more preferably 24 or less. In particular, an aliphatic dicarboxylic acid having an even number of carbon atoms is preferable.
Specific examples of the aliphatic carboxylic acid include acetic acid, neodecanoic acid, lauric acid, neodecanoic acid, myristic acid, palmitic acid, stearic acid, arachidic acid, behenic acid, lignosericic acid, cellotic acid, montanic acid and melicic acid. From the viewpoint of physical properties, acetic acid, neodecanoic acid, and stearic acid are preferable, and stearic acid is more preferable.
The cobalt salt in this embodiment is preferably cobalt stearate. The cobalt stearate is preferably (C ₁₇ H ₃₅ COO) ₂ Co.

The content of the cobalt atom in the cobalt salt (preferably cobalt stearate) in the resin of the present embodiment is preferably 10% by mass or more, preferably 50% by mass or more, based on 100 parts by mass of the xylylene diamine-based polyamide resin. It is more preferable that it is 80 mass ppm or more, and it is further preferable that it is 80 mass ppm or more. By setting the value to the lower limit or higher, the polyamide resin tends to be easily decomposed to a molecular weight that is susceptible to biodegradation. Further, the content of the cobalt atom in the cobalt salt (preferably cobalt stearate) in the resin of the present embodiment is preferably 2000 mass ppm or less, more preferably 1800 mass ppm or less, and 1500 mass ppm or less. It is more preferably 1200 mass ppm or less, further preferably 1000 mass ppm or less, and even more preferably 800 mass ppm or less. By setting the value to the upper limit or less, deterioration and poor appearance during preparation of the polyamide resin tend to be effectively suppressed.
The fiber of the present embodiment may contain only one type of cobalt salt, or may contain two or more types of cobalt salt. When two or more kinds are contained, it is preferable that the total amount is within the above range.

<Other ingredients>
The fiber of the present embodiment may contain components other than the polyamide resin and the cobalt salt as long as the purpose and effect of the present embodiment are not impaired. Specific examples of the other components include thermoplastic resins other than polyamide resins, antioxidants, heat stabilizers, hydrolysis resistance improvers, weather stabilizers, matting agents, ultraviolet absorbers, nucleating agents, and plasticizers. , Dispersant, flame retardant, antistatic agent, anticoloring agent, antigelling agent, coloring agent, mold release agent, surface activator, dyeing agent and the like. For these details, the description in paragraphs 0130 to 0155 of Japanese Patent No. 4894982, the description in paragraph 0021 of Japanese Patent Application Laid-Open No. 2010-281827, and the description in paragraph 0036 of Japanese Patent Application Laid-Open No. 2016-223037 can be referred to. Is incorporated herein.
Examples of thermoplastic resins other than polyamide resins include polyolefin resins such as polyethylene and polypropylene, polyester resins such as polyethylene terephthalate and polybutylene terephthalate, polycarbonate resins, polyoxymethylene resins, polyether ketones, polyether sulfones, and thermoplastic polys. Examples thereof include etherimide. The fiber of the present embodiment can be configured to substantially contain no thermoplastic resin other than the polyamide resin. The term "substantially free" means that, for example, in the fiber of the present embodiment, the content of the thermoplastic resin other than the polyamide resin is 5% by mass or less of the mass of the polyamide resin.
Further, the fiber of the present embodiment may contain a filler such as glass fiber or carbon fiber, but it is preferable that the fiber does not substantially contain the filler. The term "substantially free of filler" means, for example, that the blending amount of the filler is 3% by mass or less of the fiber of the present embodiment.
The fibers of the present embodiment can also be configured to be substantially free of plasticizers (eg, aromatic ester compounds). The term "substantially free of plasticizer" means that, for example, the blending amount of the plasticizer is less than 0.5 part by mass with respect to 100 parts by mass of the polyamide resin contained in the fiber of the present embodiment. 3 parts by mass or less is preferable, and 0.1 parts by mass or less is more preferable. With such a configuration, the effect of the present invention tends to be exhibited more effectively.
Further, the fiber of the present embodiment can be imparted with arbitrary surface properties by subjecting it to plasma treatment. For details, the description of JP-A-06-182195 can be taken into consideration, and the contents thereof are incorporated in the present specification.

<Stretching>
The fibers of the present embodiment may or may not be stretched, but are preferably stretched. By being stretched, there is a tendency to obtain fibers having higher strength. The stretching is preferably in the longitudinal direction of the fiber (fiber length direction). Further, it may be a one-step stretching or a two-step or more stretching, but a two-step stretching is preferable. The draw ratio (total draw ratio) is preferably 2.5 times or more, more preferably 3.0 times or more, further preferably 3.5 times or more, and 4.0 times or more. It is even more preferable, it is even more preferable that it is 4.5 times or more, and it is even more preferable that it is 5.0 times or more. The upper limit of the draw ratio is preferably 8.0 times or less, more preferably 7.5 times or less, further preferably 7.0 times or less, and 6.5 times or less. Is even more preferable, 6.0 times or less is even more preferable, and 5.5 times or less is even more preferable.

<Characteristics and physical properties of fibers>
The fibers of this embodiment are preferably biodegradable. The biodegradability refers to the ability to be finally decomposed into water and carbon dioxide by microorganisms and the like, and includes, for example, those in which a decrease in molecular weight is observed when stored for a certain period in a compost environment.
The fiber of the present embodiment preferably has a biodegradation degree of 10% or more, more preferably 15% or more after being stored for 90 days in a compost environment at 58 ± 2 ° C. and 100% relative humidity. It is more preferably 21% or more, further preferably 25% or more, further preferably 30% or more, and even more preferably 35% or more. Ideally, the upper limit of the degree of biodegradation is 100%, but for example, 80% or less, and even 70% or less, sufficiently satisfy the required performance. Here, the degree of biodegradation (%) is [(total CO ₂ generation amount during storage for 90 days in a compost environment) / (theoretical carbon dioxide generation amount calculated from the composition formula)] × 100. For details, follow the description of the examples.

The length (mass average length) of the fiber of the present embodiment is not particularly specified, but is usually 2 cm or more, preferably 0.1 m or more, more preferably 1 m or more, still more preferably 100 m or more. be. The upper limit of the fiber length (mass average length) is preferably 20,000 m or less, more preferably 1,000 m or less, and further preferably 100 m or less.

The fiber of the present embodiment may be a monofilament or a multifilament, but is preferably a multifilament. By using a multifilament, in addition to facilitating processing into various molded bodies, the multifilament has a finer single fineness than the monofilament, so that biodegradation tends to proceed more effectively.
When the filament of the present embodiment is a multifilament, the number of filaments constituting one multifilament is preferably 10 or more, more preferably 20 or more, and may be 30 or more. Further, the upper limit of the number of filaments constituting one multifilament is preferably 100 or less, more preferably 60 or less, and further preferably 55 or less. Within such a range, fusion between single yarns at the time of spinning can be effectively prevented.
In the case of using a multifilament, a sizing agent may be used, and the type of the sizing agent is not particularly specified as long as it has a function of converging polyamide resin fibers, but mineral oil, animal / vegetable oil, etc. Examples of surfactants include oils, nonionic surfactants, anionic surfactants and amphoteric surfactants. More specifically, ester compounds, alkylene glycol compounds, polyolefin compounds, phenyl ether compounds, polyether compounds, silicone compounds, polyethylene glycol compounds, amide compounds, sulfonate compounds, phosphate compounds, Carboxylate compounds and combinations of two or more thereof are preferable. The amount of the sizing agent is preferably 0.1 to 5.0 parts by mass with respect to 100 parts by mass of the fiber.

The lower limit of the fineness (single fineness) of the fiber of the present embodiment is preferably 50d (denier) or more, more preferably 100d or more, further preferably 300d or more, and further preferably 500d or more. It is more preferably 600d or more, and even more preferably 600d or more. The upper limit is preferably 1500d or less, more preferably 1300d or less, further preferably 1200d or less, and even more preferably 1100d or less.
The fineness is measured by the method described in Examples described later.

The cross section of the fiber of this embodiment is usually circular. The term "circle" as used herein means not only a circle in a mathematical sense but also a circle in the technical field of the present embodiment, which is generally recognized as a circle. Further, the cross section of the fiber in the present embodiment may have a shape other than a circular shape, and may have a flat shape such as an elliptical shape or an oval shape.

The linear strength of the fiber of the present embodiment is preferably 3.0 gf / d or more, more preferably 3.5 gf / d or more, further preferably 4.0 gf / d or more, and further preferably. May be 4.5 gf / d or more, particularly 5.0 gf / d or more. By setting the value to the lower limit or more, the effect of preventing breakage due to the load in the tensile direction of the fiber tends to be further improved. The upper limit of the linear strength of the fiber of the present embodiment is not particularly defined, but even if it is, for example, 10.0 gf / d or less, further 8.0 gf / d or less, and particularly 7.0 gf / d or less. It meets the required performance.

The knot strength of the fiber of the present embodiment is preferably 2.0 gf / d or more, more preferably 2.5 gf / d or more, further preferably 3.0 gf / d or more, and further preferably. May be 3.5 gf / d or more, particularly 3.8 gf / d or more. By setting the value to the lower limit or more, the effect of suppressing breakage at a knot, for example, in fishing net applications, tends to be further improved. The upper limit of the knot strength of the fiber of the present embodiment is not particularly defined, but even if it is, for example, 8.0 gf / d or less, further 6.0 gf / d or less, and particularly 7.0 gf / d or less. It meets the required performance.
The linear strength and the nodular strength are measured by the methods described in Examples described later.

<Manufacturing method>
The fiber of the present embodiment is obtained by molding a composition containing a polyamide resin and a cobalt salt. The molding method is arbitrary, and it may be molded into a desired shape by any conventionally known molding method such as melt spinning. For example, the description in paragraphs 0051 to 0058 of International Publication No. 2017/010389 can be taken into consideration, and these contents are incorporated in the present specification.
The molding conditions and the shape after molding may be appropriately selected and determined according to the intended use. For example, fibers for fishing nets, fibers for fishing lines, fibers for industrial materials, fibers for woven fabrics such as clothing and carpets, and racket guts. It may be changed as appropriate depending on the above.

<Use>
The fiber of the present embodiment may be used as it is, or may be processed into a thread-like material such as a mixed fiber yarn, a braided cord, or a twisted cord. It is also preferably used as a molded body for woven fabrics, knitted fabrics, non-woven fabrics and the like. Further, the molded product may be a finished product, a part, or a material to be further processed.
The fiber of this embodiment may be wound around a core material. That is, it can also be a winding body having a core material and fibers wound around the core material.
The fiber or molded body of the present embodiment includes transport machine parts such as automobiles, general machine parts, precision machine parts, electronic / electrical equipment parts, OA equipment parts, building materials / housing related parts, medical equipment, leisure sports goods (for example,). (Fishing thread), agricultural, forestry and fishery products, play equipment, medical products, food packaging films, daily necessities such as clothing, defense and aerospace products.
In particular, since the fiber or molded body of the present embodiment is excellent in biodegradability, it is preferably used for filter cloths, leisure sports equipment (for example, fishing line), and fishing nets, and is preferably used for fishing nets.
The fibers of the present embodiment and the molded product of the present embodiment can be discarded by biodegrading. The fiber and the molded product of the present embodiment can be decomposed to the molecular level by the action of microorganisms, and finally become carbon dioxide and water, which can be circulated to the natural world. Therefore, it is advantageous in that it can be disposed of naturally without being destroyed. That is, the present specification also discloses a method for disposing of fibers, which comprises biodegrading the fibers or molded products of the present embodiment.

Hereinafter, the present invention will be described in more detail with reference to examples. The materials, amounts used, ratios, treatment contents, treatment procedures, etc. shown in the following examples can be appropriately changed as long as they do not deviate from the gist of the present invention. Therefore, the scope of the present invention is not limited to the specific examples shown below.
When the measuring device or the like used in the examples is difficult to obtain due to a discontinued number or the like, measurement can be performed using another device having the same performance.

1. 1. Raw material <Synthesis example of MXD10>
In a reaction can with a jacket equipped with a stirrer, a splitter, a cooler, a thermometer, a dropping tank and a nitrogen gas introduction tube, 60.00 mol of precisely weighed sebacic acid was placed, sufficiently replaced with nitrogen, and a small amount of nitrogen flow was added. The temperature was raised to 170 ° C. below to dissolve sebacic acid and bring it into a uniform flow state. To this, 60 mol of m-xylylenediamine was added dropwise over 160 minutes with stirring. During this period, the internal pressure of the reaction system was set to normal pressure, the internal temperature was continuously raised to 250 ° C., and the water distilled with the dropping of paraxylylenediamine was removed from the system through a condenser and a cooler. After completion of the addition of paraxylylenediamine, the reaction was continued for 10 minutes while maintaining the liquid temperature of 250 ° C. Then, the internal pressure of the reaction system was continuously reduced to 600 Torr for 10 minutes, and then the reaction was continued for 20 minutes. During this time, the reaction temperature was continuously raised to 260 ° C. After completion of the reaction, a pressure of 0.3 MPa was applied to the inside of the reaction can with nitrogen gas, and the polymer was taken out as a strand from a nozzle at the bottom of the polymerization tank, cooled with water and cut into pellets to obtain pellets of a molten polymer product. The pellet was dried in a vacuum dryer at 150 ° C. for 5 hours. The melting point of the obtained polyamide resin (MXD10) measured according to DSC was 191 ° C.
The mass ratio of the xylylenediamine structure is 44.4% by mass.

<Synthesis example of PXD10>
In a reaction can with a jacket equipped with a stirrer, a splitter, a cooler, a thermometer, a dropping tank and a nitrogen gas introduction tube, 60.00 mol of precisely weighed sebacic acid was placed, sufficiently replaced with nitrogen, and a small amount of nitrogen flow was added. The temperature was raised to 170 ° C. below to dissolve sebacic acid and bring it into a uniform flow state. To this, 60 mol of paraxylylenediamine was added dropwise over 160 minutes with stirring. During this period, the internal pressure of the reaction system was set to normal pressure, the internal temperature was continuously raised to 285 ° C., and the water distilled with the dropping of paraxylylenediamine was removed from the system through a condenser and a cooler. After completion of the addition of paraxylylenediamine, the reaction was continued for 10 minutes while maintaining the liquid temperature of 290 ° C. Then, the internal pressure of the reaction system was continuously reduced to 600 Torr for 10 minutes, and then the reaction was continued for 20 minutes. During this time, the reaction temperature was continuously raised to 305 ° C. After completion of the reaction, a pressure of 0.3 MPa was applied to the inside of the reaction can with nitrogen gas, and the polymer was taken out as a strand from a nozzle at the bottom of the polymerization tank, cooled with water and cut into pellets to obtain pellets of a molten polymer product. The pellet was dried in a vacuum dryer at 150 ° C. for 5 hours. The melting point of the obtained polyamide resin (PXD10) measured according to DSC was 290 ° C.
The mass ratio of the xylylenediamine structure is 44.4% by mass.

<Synthesis example of MXD12>
In a reaction can with a jacket equipped with a stirrer, a splitter, a cooler, a thermometer, a dropping tank and a nitrogen gas introduction tube, 60.00 mol of the precisely weighed 1,12-dodecanedic acid was placed and sufficiently replaced with nitrogen. Further, the temperature was raised to 180 ° C. under a small amount of nitrogen stream to dissolve 1,12-dodecanedic acid to obtain a uniform flow state. To this, 60 mol of m-xylylenediamine was added dropwise over 160 minutes with stirring. During this period, the internal pressure of the reaction system was set to normal pressure, the internal temperature was continuously raised to 250 ° C., and the water distilled with the dropping of m-xylylenediamine was removed from the system through a condenser and a cooler. After the addition of m-xylylenediamine was completed, the reaction was continued for 10 minutes while maintaining the liquid temperature of 250 ° C. Then, the internal pressure of the reaction system was continuously reduced to 600 Torr for 10 minutes, and then the reaction was continued for 20 minutes. During this time, the reaction temperature was continuously raised to 260 ° C. After completion of the reaction, a pressure of 0.3 MPa was applied to the inside of the reaction can with nitrogen gas, and the polymer was taken out as a strand from a nozzle at the bottom of the polymerization tank, cooled with water and cut into pellets to obtain pellets of a molten polymer product. The obtained pellets were placed in a tumbler (rotary vacuum chamber) having a heat medium heating cloak at room temperature. The inside of the tank was depressurized (0.5 to 10 Torr) while rotating the tumbler, the flow heat medium was heated to 150 ° C., the pellet temperature was raised to 130 ° C., and the temperature was maintained at that temperature for 3 hours. After that, nitrogen was introduced again to bring it to normal pressure, and cooling was started. When the temperature of the pellet became 70 ° C. or lower, the pellet was taken out from the tank to obtain a solid phase polymer product.
The melting point of the obtained polyamide resin (MXD12) measured according to DSC was 190 ° C.
The mass ratio of the xylylenediamine structure is 40.6% by mass.

<Example of MP12 synthesis>
In a reaction can with a jacket equipped with a stirrer, a splitter, a cooler, a thermometer, a dropping tank and a nitrogen gas introduction tube, 60.00 mol of the precisely weighed 1,12-dodecanedic acid was placed and sufficiently replaced with nitrogen. Further, the temperature was raised to 180 ° C. under a small amount of nitrogen stream to dissolve 1,12-dodecanedic acid to obtain a uniform flow state. To this, 60 mol of para / m-xylylenediamine in which 40 mol% of the diamine component was paraxylylenediamine and 60 mol% was metaxylylenediamine was added dropwise over 160 minutes under stirring. During this period, the internal pressure of the reaction system was set to normal pressure, the internal temperature was continuously raised to 250 ° C., and the water distilled with the dropping of para / m-xylylenediamine was removed from the system through a condenser and a cooler. .. After completion of the addition of para / m-xylylenediamine, the reaction was continued for 10 minutes while maintaining the liquid temperature of 250 ° C. Then, the internal pressure of the reaction system was continuously reduced to 600 Torr for 10 minutes, and then the reaction was continued for 20 minutes. During this time, the reaction temperature was continuously raised to 260 ° C. After completion of the reaction, a pressure of 0.3 MPa was applied to the inside of the reaction can with nitrogen gas, and the polymer was taken out as a strand from a nozzle at the bottom of the polymerization tank, cooled with water and cut into pellets to obtain pellets of a molten polymer product. The obtained pellets were placed in a tumbler (rotary vacuum chamber) having a heat medium heating cloak at room temperature. The inside of the tank was depressurized (0.5 to 10 Torr) while rotating the tumbler, the flow heat medium was heated to 150 ° C., the pellet temperature was raised to 130 ° C., and the temperature was maintained at that temperature for 3 hours. After that, nitrogen was introduced again to bring it to normal pressure, and cooling was started. When the temperature of the pellet became 70 ° C. or lower, the pellet was taken out from the tank to obtain a solid phase polymer product.
The melting point of the obtained polyamide resin (MP12) measured according to DSC was 216 ° C.
The mass ratio of the xylylenediamine structure is 40.6% by mass.

<Synthesis example of MXD20>
In the above-mentioned synthesis example of MP12, 100 mol% of the diamine component was used as m-xylylenediamine, and 1,12-dodecanedioic acid was changed to 1,20-icosanedioic acid, and the same synthesis was obtained.
The melting point of the obtained polyamide resin (MXD20) measured according to DSC was 168 ° C.
The mass ratio of the xylylenediamine structure is 30.3% by mass.

Cobalt stearate (StCo): manufactured by Kanto Chemical Co., Inc., product number: 07423-02

2. 2. Examples 1 to 5, Comparative Examples 1 to 5
<Manufacturing of fiber>
The polyamide resin and cobalt stearate were weighed and blended with a tumbler so as to have the compositions shown in Table 1 or Table 2 described later. This was melted using a single-screw extruder and spun through a spinneret at a spinning temperature of + 20 ° C., which is the melting point of the polyamide resin. It was taken up in a water bath having a temperature of 50 ° C. and continuously stretched without being wound once. Stretching was carried out in two stages of stretching and one stage of heat fixing, and a hot water bath at 75 ° C. was used in the first stage stretching region and a dry heat air bath at 180 ° C. in the second stage stretching was used as the stretching means. As the stretching conditions, the total stretching ratio was 3 to 4.5, the two-stage stretching ratio was 1.0 to 1.5, the relaxation rate was 5%, the stretching ratio shown in Table 1 or Table 2, and the fiber (monofilament) was used. Obtained.

<Fineness>
The fineness of the fibers (positive amount fineness) at the time of drying was measured according to the provisions of JIS L 1013: 2010. The unit is shown in denier (d).

<Linear strength>
For the dry fibers, the linear strength was measured according to JIS L 1013: 2010. The unit of linear strength is gf / d.

<Nodule strength>
For dry fibers, nodular strength was measured according to JIS L 1013: 2010. The unit of nodule strength is gf / d.

<Biodegradation>
The degree of biodegradation was measured according to JIS K 6953-1 (aerobic compost system biodegradation test method). It was mixed with 10 g of fiber and compost having a dry mass of 60 g to give a water content of 45 to 50% by mass. The mixture was placed in a composting environment at 58 ± 2 ° C. and 100% relative humidity, the air was saturated with water to aerate a gas excluding carbon dioxide, and a biodegradation test was conducted for 90 days. The amount of carbon dioxide generated was measured, and the degree of biodegradation was calculated from the total amount of theoretical carbon dioxide generated according to the following formula.
Biodegradation degree (%) = [(total amount of CO ₂ generated during storage in compost environment for 90 days) / (total amount of theoretical carbon dioxide generated)] x 100
The total amount of theoretical carbon dioxide generated was calculated from the total organic carbon amount (TOC) of the test material and the sample amount of 10 g measured in advance with a CHN analyzer according to the following formula.
Theoretical carbon dioxide generation (g) = [(total organic carbon amount (TOC) of test material / 100] × 3.67 × 10
As the compost, YK-11 manufactured by Yawata Corporation was used. A non-dispersive infrared analyzer (LI-830 manufactured by LI-COR) was used to measure the amount of carbon dioxide. A PE2400 series II manufactured by PerkinElmer was used as the CHN analyzer.

The blending amount in the column of StCo in Tables 1 and 2 is indicated by the amount of cobalt atoms in the amount of cobalt stearate with respect to 100 parts by mass of the polyamide resin.
As is clear from the above results, the fiber of the present invention was excellent in biodegradability (Examples 1 to 5). In particular, as is clear from the comparison between Example 1 and Comparative Example 1, Example 2 and Comparative Example 2, Example 3 and Comparative Example 3, Example 4 and Comparative Example 4, and Example 5 and Comparative Example 5, raw. Before decomposition, it had the same strength as fibers that did not contain cobalt salts and were not excellent in biodegradability.

Claims (13)

Contains polyamide resin and cobalt salt,
The polyamide resin contains a diamine-derived structural unit and a dicarboxylic acid-derived structural unit, and 50 mol% or more of the diamine-derived structural unit is derived from xylylene diamine and 50 mol% of the dicarboxylic acid-derived structural unit. The above contains a xylylene diamine-based polyamide resin derived from an α, ω-linear aliphatic dicarboxylic acid having 8 to 22 carbon atoms.
fiber. The fiber according to claim 1, wherein the mass ratio of the xylylenediamine structure in the xylylenediamine-based polyamide resin is 20 to 70% by mass; where the mass ratio of the xylylenediamine structure is [(polyamide resin). It is a value calculated from (mass of xylylenediamine structure in) / (mass of total polyamide resin)] × 100. The fiber according to claim 1 or 2, wherein the α, ω-linear aliphatic dicarboxylic acid having 8 to 22 carbon atoms contains the α, ω-linear aliphatic dicarboxylic acid having carbon atoms. The fiber according to claim 1 or 2, wherein the α, ω-linear aliphatic dicarboxylic acid having 8 to 22 carbon atoms contains 1,12-dodecanedioic acid. The fiber according to any one of claims 1 to 4, wherein the cobalt salt contains a carboxylic acid salt of cobalt. The fiber according to any one of claims 1 to 4, wherein the cobalt salt contains cobalt stearate. The fiber according to any one of claims 1 to 6, wherein the content of the cobalt atom in the cobalt salt is 10 to 2000 mass ppm with respect to 100 parts by mass of the xylylenediamine-based polyamide resin. The fiber according to any one of claims 1 to 7, which is biodegradable. The fiber according to any one of claims 1 to 8, wherein the degree of biodegradation after storing the fiber in a compost environment of 58 ± 2 ° C. and 100% relative humidity for 90 days is 10% or more. The degree of biodegradation (%) is [(total CO ₂ generation amount during storage for 90 days in a compost environment) / (theoretical carbon dioxide generation amount calculated from the composition formula)] × 100. A molded body formed from the fiber according to any one of claims 1 to 9. The molded body according to claim 10, wherein the molded body is a fishing net. A method for disposing of fibers, which comprises biodegrading the fibers according to any one of claims 1 to 9. A method for disposing of a molded product, which comprises biodegrading the molded product according to claim 10 or 11.