Polyphenylene ether fiber, activated carbon fiber, and method for producing polyphenylene ether fiber

Abstract

The purpose of the present invention is to provide a PPE fiber with excellent oxidation resistance and an activated carbon fiber that uses the PPE fiber as raw stock. Another purpose of the present invention is to provide a method that makes it possible to efficiently produce PPE fibers having excellent oxidation resistance. The present invention relates to a polyphenylene ether fiber that contains a polyphenylene ether component and is characterized in that the amount of gas generated when the polyphenylene ether fiber is heated at 320°C for 10 minutes is 1500 ppm or more. The present invention also relates to a method for producing a polyphenylene ether fiber, the method being characterized in that: said method includes a step in which a polyphenylene ether serving as a starting material is melt-extruded using an extruder equipped with a cylinder and a screw, and a step in which the molten polyphenylene ether is discharged from a spinning nozzle and spun; and degassing is not performed in the step for melt-extruding.

Description

Polyphenylene ether fibers, activated carbon fibers, and methods for producing polyphenylene ether fibers

[0001] The present invention relates to polyphenylene ether fibers, activated carbon fibers, and a method for producing polyphenylene ether fibers.

[0002] Polyphenylene ether (hereinafter sometimes referred to as "PPE") has excellent heat resistance, flame retardancy, strength, and chemical resistance, and molded articles formed from polyphenylene ether are used in a wide range of fields. Known molded articles formed from polyphenylene ether include polyphenylene ether melt-spun fibers and fabrics and nonwovens formed from these fibers (for example, Patent Document 1).

[0003] International Publication No. 2021 / 060210

[0004] Because PPE is easily oxidized, the surface of PPE fibers could oxidize during the formation of melt-spun fibers. This oxidation made the PPE fiber surface difficult to melt, making it challenging to form molded products such as nonwoven fabrics using PPE fibers. Therefore, oxidation resistance was required for PPE fibers.

[0005] Patent Document 1 shows that melt-molding is possible even when PPE is used alone or in high concentrations, and that PPE melt-spun fibers with excellent properties such as mechanical strength can be provided. However, no consideration has been given to suppressing the oxidation of PPE melt-spun fibers.

[0006] Therefore, an object of the present invention is to provide PPE fibers with excellent oxidation resistance and activated carbon fibers using said PPE fibers as raw material. Furthermore, another object of the present invention is to provide a method for producing PPE fibers that can efficiently produce PPE fibers with excellent oxidation resistance.

[0007] As a result of diligent research, the inventors of this invention discovered that the above problem can be solved by having PPE fibers contain a certain amount of gas, and thus completed the present invention.

[0008] In other words, the present invention relates to a PPE fiber containing a PPE component, characterized in that the amount of gas generated when the PPE fiber is heated at 320°C for 10 minutes is 1500 ppm or more.

[0009] It is preferable that the oxidation onset temperature (IOT) of the PPE fiber is 206°C or higher.

[0010] It is preferable that the PPE fibers contain an amine compound.

[0011] It is preferable that the amine compound content is 500 ppm or more relative to the total amount of PPE fibers.

[0012] It is preferable that the PPE component has a dislocation structure in which it is connected by ortho bonds within a repeating unit consisting of consecutive para bonds.

[0013] The repeating unit formed by the aforementioned para-position bonding is given by the following general formula (1): (In the formula, R １ , R ２ Each is independently a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms which may have substituents, and R ３ Each of these is a repeating unit represented by (which independently represents a hydrocarbon group having 1 to 10 carbon atoms, which may have substituents), and the rearrangement structure is represented by the following general formula (2): (In the formula, R １ , R ２ Each is independently a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms which may have substituents, and R ３ Each is independently a hydrocarbon group having 1 to 10 carbon atoms, which may have substituents, and R ３’ is the aforementioned R ３ It is preferable that the structure be represented by (representing a divalent group from which one hydrogen atom has been removed).

[0014] It is preferable that the amount of dislocations in the PPE component having the dislocation structure is 0.05 mol% or more relative to the total PPE structural units in the PPE component.

[0015] Preferably, the content of the PPE component is 95% by mass or more of the total components forming the fiber.

[0016] Furthermore, the present invention relates to activated carbon fibers characterized by using the aforementioned PPE fibers as raw material.

[0017] Furthermore, the present invention relates to a method for producing PPE fibers, comprising the steps of melting and extruding raw material PPE using an extruder equipped with a cylinder and a screw, and spinning the molten PPE by extruding it from a spinning nozzle, characterized in that degassing is not performed in the melting and extruding step.

[0018] The present invention provides PPE fibers with excellent oxidation resistance, activated carbon fibers using said PPE fibers as raw material, and a method for producing PPE fibers that can efficiently produce PPE fibers with excellent oxidation resistance.

[0019] The manufacturing method of the present invention is characterized by not performing degassing in the melt extrusion process. By not performing degassing, the resulting PPE fibers contain a certain amount of gas, and as a result, have excellent oxidation resistance.

[0020] This is a schematic cross-sectional view showing one embodiment of the method for producing PPE fibers according to the present invention.

[0021] 1. PPE Fibers The PPE fibers of the present invention contain PPE components and are characterized in that the amount of gas generated when the PPE fibers are heated at 320°C for 10 minutes is 1500 ppm or more.

[0022] The amount of gas can be measured by GC-MS analysis. Specifically, using a pyrolysis gas chromatograph (Py-GC / MS), 2 mg of the obtained thread was added to a sample cup for Py-GC / MS analysis, and the analysis was performed under the conditions shown below. (Py-GC / MS analysis conditions) Instrument: PY-2020iD (Frontier LAB) / QP-2010Plus (Shimadzu Corporation) Sample heating conditions: 320°C × 10 min Carrier / heating atmosphere gas: He Column: Ultra ALLOY-5 (MS / HT) (length 30 m, inner diameter 0.25 mm, film thickness 0.25 μm) Column oven temperature: 40°C (2 min) - 10°C / min - 300°C (15 min) Inlet pressure: 80 kPa Inlet temperature: 320°C Split ratio: 30 Ion source: EI method Ion source temperature: 250°C Ionization voltage: 70 eV Interface temperature: 320°C MS measurement mode: SCAN Mass measurement range: m / z 30-550 The quantitative values ​​were calculated by conversion quantification using octamethylcyclotetrasiloxane as a standard substance.

[0023] The PPE fibers of the present invention have a gas content of 1500 ppm or more, which suppresses oxidation of the PPE fibers (i.e., exhibits excellent oxidation resistance). The gas content is preferably 1600 ppm or more, more preferably 1700 ppm or more, and even more preferably 1800 ppm or more. Furthermore, the gas content is preferably 5000 ppm or less, more preferably 4000 ppm or less, and even more preferably 3000 ppm or less. The gas content can be adjusted by appropriately setting the degassing process in the PPE melt extrusion process, as well as the extrusion temperature, screw configuration, screw rotation speed, screw tip pressure, etc.

[0024] The PPE fibers of the present invention preferably have an oxidation onset temperature (IOT) of 206°C or higher, more preferably 207°C or higher, and even more preferably 210°C or higher. An IOT of 206°C or higher is preferable because it provides excellent oxidation resistance for the PPE fibers. Furthermore, the oxidation onset temperature is preferably 280°C or lower, more preferably 270°C or lower, and even more preferably 260°C or lower.

[0025] From the perspective of light weight, the average number of air bubbles in the cross-section of the PPE fiber of the present invention is preferably 1 or more, more preferably 2 or more per 1 mm of the PPE fiber cross-section. Also, the number of air bubbles is preferably 100 or less, more preferably 80 or less per 1 mm of the PPE fiber cross-section. ２ From the perspective of light weight, the average number of air bubbles in the cross-section of the PPE fiber of the present invention is preferably 1 or more, more preferably 2 or more per 1 mm of the PPE fiber cross-section. Also, the number of air bubbles is preferably 100 or less, more preferably 80 or less per 1 mm of the PPE fiber cross-section. ２ From the perspective of light weight, the average number of air bubbles in the cross-section of the PPE fiber of the present invention is preferably 1 or more, more preferably 2 or more per 1 mm of the PPE fiber cross-section. Also, the number of air bubbles is preferably 100 or less, more preferably 80 or less per 1 mm of the PPE fiber cross-section.

[0026] From the perspective of oxidation resistance, the PPE fiber of the present invention preferably contains an amine compound. The amine compound may be added during the PPE fiber manufacturing process or may be an amine compound derived from a catalyst contained in the PPE raw material. In the latter case, there is no need to separately add an amine compound during the PPE fiber manufacturing process.

[0027] Examples of the amine compound include N-butylidenebutylamine, dibutylamine, dimethylamine, diethylamine, diethanolamine, diisopropanolamine, N-methylethanolamine, N-ethylethanolamine, pyrrolidine, piperidine, morpholine, trimethylamine, triethylamine, tripropylamine, tributylamine, trioctylamine, diisopropylethylamine, triethanolamine, triisopropanolamine, N-dimethylaminoethanol, N-diethylaminoethanol, pyridine, 4-dimethylaminopyridine, quinoline, isoquinoline, etc. Among these, from the perspective of oxidation resistance, N-butylidenebutylamine and dibutylamine are preferred.

[0028] The content of the amine compound is preferably 500 ppm or more, more preferably 600 ppm or more, and even more preferably 700 ppm or more based on the total amount of the PPE fiber. Also, the upper limit value of the content of the amine compound is not particularly limited, but for example, it can be 10000 ppm or less.

[0029] The glass transition temperature of the PPE fiber of the present invention is preferably 170°C or higher, more preferably 175°C or higher, and even more preferably 180°C or higher. Having the glass transition temperature within this range provides extremely high heat resistance. While there is no particular upper limit, from the viewpoint of moldability, it is preferably 300°C or lower, and more preferably 250°C or lower.

[0030] The PPE fibers of the present invention may also be short fibers. These short fibers can be obtained, for example, by cutting fibers that have been formed into a tow by splicing PPE fibers together.

[0031] The following describes the PPE components contained in the PPE fibers of the present invention.

[0032] <PPE components> The PPE components are not particularly limited and include those commonly used in this field. Specifically, the following general formula (1): (In the formula, R １ , R ２ Each is independently a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms, which may have substituents, and R ３ Examples include homopolymers having repeating units represented by (wherein each of them independently represents a hydrocarbon group having 1 to 10 carbon atoms which may have substituents), copolymers containing two or more different repeating units of general formula (1), and copolymers having repeating units of general formula (1) and repeating units other than general formula (1).

[0033] In the above general formula (1), R １ ~R ３ Examples of hydrocarbon groups having 1 to 10 carbon atoms include alkyl groups having 1 to 10 carbon atoms such as methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, t-butyl, pentyl, cyclopentyl, hexyl, cyclohexyl, octyl, and decyl groups; aryl groups having 6 to 10 carbon atoms such as phenyl, 4-methylphenyl, 1-naphthyl, and 2-naphthyl groups; and aralkyl groups having 7 to 10 carbon atoms such as benzyl, 2-phenylethyl, and 1-phenylethyl groups.

[0034] If the hydrocarbon group has substituents, examples of substituents include halogen atoms such as fluorine atoms, and alkoxy groups such as methoxy groups. Specific examples of hydrocarbon groups with substituents include, for example, trifluoromethyl groups.

[0035] Among these, R １ , R ２ As for the hydrogen atom, a methyl group is preferred, and a hydrogen atom is more preferred, R ３ A methyl group is preferred as the component.

[0036] Specific examples of the repeating unit of the general formula (1) include repeating units derived from 2,6-dimethyl-1,4-phenylene ether, 2,6-diethyl-1,4-phenylene ether, 2-methyl-6-ethyl-1,4-phenylene ether, and 2,6-dipropyl-1,4-phenylene ether. Among these, the repeating unit derived from 2,6-dimethyl-1,4-phenylene ether is preferred.

[0037] Furthermore, the PPE may contain repeating units other than those of general formula (1) as long as it does not impair the effects of the present invention. The content of such repeating units other than those of general formula (1) is not particularly limited as long as it does not impair the effects of the present invention, but for example, it is preferably about 5 mol% or less in the copolymer, and more preferably it is not included.

[0038] The PPE component preferably has a dislocation structure connected by ortho bonds within a repeating unit that is continuous by para bonds. Examples of the repeating unit that is continuous by para bonds include the repeating unit represented by the above general formula (1), and examples of the dislocation structure include the following general formula (2): (In the formula, R １ , R ２ Each is independently a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms, which may have substituents, and R ３ Each is independently a hydrocarbon group having 1 to 10 carbon atoms, which may have substituents, and R ３’ is the aforementioned R ３One possible rearrangement structure is represented by (representing a divalent group from which one hydrogen atom has been removed).

[0039] In the above general formula (2), R １ ~R ３ Examples include those similar to those in general formula (1) above. The "~" in general formula (2) indicates that the structure beyond it is not particularly limited. The "~" portion may be formed from phenylene ether units connected by para bonds, or it may have a portion that is partially bonded at the ortho position.

[0040] The aforementioned R ３’ is the aforementioned R ３ This represents a divalent group from which one hydrogen atom has been removed, and it is preferably a methylene group.

[0041] The PPE component having the aforementioned rearrangement structure is preferably a homopolymer having repeating units of general formula (1), a copolymer containing two or more different repeating units of general formula (1), or a copolymer containing repeating units of general formula (1) and repeating units other than general formula (1) that has a rearrangement structure represented by general formula (2).

[0042] If the PPE component has a dislocation structure, the amount of the dislocation structure (hereinafter also referred to as "dislocation amount") is preferably 0.05 mol% or more, preferably 0.1 mol% or more, and more preferably 0.15 mol% or more, relative to the total structural units constituting the PPE component. Furthermore, the dislocation amount is preferably 15 mol% or less, more preferably 10 mol% or less, and even more preferably 8 mol% or less. Having the dislocation amount in the PPE component having a dislocation structure within the above range is preferable from the viewpoint of achieving a viscosity suitable for spinning and oxidation resistance.

[0043] The aforementioned dislocation structure is observed in the nuclear magnetic resonance spectrum ( １In 1H-NMR measurements, it is preferable to show peaks in the ranges of 3.8–4.0 ppm and 6.8–7.0 ppm. Typically, PPE shows a peak around 6.4–6.6 ppm, which is a peak originating from the hydrogen atoms at positions 3 and 5 of the benzene ring in the PPE main chain. PPE having the rearrangement structure shows peaks in the ranges of 3.8–4.0 ppm and 6.8–7.0 ppm, in addition to the peak around 6.4–6.6 ppm. The chemical shift at 3.8–4.0 ppm is due to R in the rearrangement structure. ３’ This originates from the proton of the divalent group (e.g., methylene group) shown, and the chemical shift of 6.8 to 7.0 ppm is due to the R at the 3 and 5 positions of PPE in the rearrangement structure. １ , R ２ It originates from the protons of the group (for example, the hydrogen atoms at positions 3 and 5 of the benzene ring bonded to the ortho position via a methylene group).

[0044] The molecular weight of the PPE is not particularly limited, but it is preferably 40,000 to 100,000 in weight-average molecular weight (Mw), and more preferably 50,000 to 80,000. The number-average molecular weight (Mn) is preferably 7,000 to 30,000, and more preferably 8,000 to 20,000. The molecular weight dispersion (Mw / Mn) is preferably 3.5 to 8.0, and more preferably 4.0 to 6.0.

[0045] The PPE component content is preferably 95% by mass or more of the total components forming the PPE fiber, more preferably 98% by mass or more, and even more preferably substantially composed of only PPE components (100% by mass). Having the PPE component content in the PPE fiber within the above range is preferable because it not only provides excellent mechanical strength to the resulting fiber, but also excellent heat resistance, chemical resistance, flame retardancy, etc.

[0046] <Components other than PPE components> The PPE fiber of the present invention may contain resin components other than the PPE components. Examples of resin components other than PPE components include styrene, polyethylene, polypropylene, polyamides such as polyamide 4, polyamide 6, polyamide 10, polyamide 11, polyamide 66, polyamide 6T, polyamide 6T / 11, polyesters such as polyethylene terephthalate and polybutylene terephthalate, and polycarbonates. However, the content of these components is preferably 5% by mass or less, more preferably 2% by mass or less, and even more preferably none (0% by mass).

[0047] Furthermore, the PPE fibers of the present invention may also contain additives such as lubricants, plasticizers, antioxidants, ultraviolet absorbers, dulling agents, and antistatic agents, to the extent that they do not impair the effects of the present invention.

[0048] The PPE fibers of the present invention are preferably manufactured by the PPE fiber manufacturing method described below.

[0049] 2. Activated Carbon Fibers The activated carbon fibers of the present invention are obtained using the PPE fibers as raw material. Specifically, the PPE fibers are treated in at least one step selected from a process consisting of infusibility treatment (for example, heat treatment at 120 to 400°C for 0.1 to 100 hours in an air atmosphere with a water vapor concentration of 0.5 to 20 vol.%) and carbonization treatment, and the resulting fibers are then activated.

[0050] The activated carbon fibers of the present invention can be suitably used in applications such as water purification, air purification, gas adsorption, water treatment, and various filters such as canisters.

[0051] 3. Method for Manufacturing PPE Fibers The method for manufacturing PPE fibers according to the present invention includes the steps of melting and extruding polyphenylene ether, which is a raw material, using an extruder equipped with a cylinder and a screw, and spinning the molten polyphenylene ether by extruding it from a spinning nozzle, characterized in that no degassing is performed in the melting and extruding step.

[0052] An example of manufacturing PPE melt-spun fibers will be explained using Figure 1. The raw material, PPE, is fed from the hopper 1 in Figure 1 into an extruder 2 equipped with a cylinder and screw. The molten PPE is discharged at a rate measured by a gear pump 3, passes through a filter material 4 composed of fine sand or the like, and is discharged from a spinning nozzle 5 to obtain melt-spun fibers. The extruder may be equipped with a degassing vent 10 as shown in Figure 1, but if it is equipped, it must be used with the degassing vent 10 closed. Furthermore, it is preferable to install a filter 6 made of a metal nonwoven fabric or the like on the filter material 4. Installing a filter 6 is preferable because it can remove foreign matter in advance and prevent clogging of the filter material 4.

[0053] Furthermore, a heat retention space 7 is provided directly below the spinning nozzle 5, and it is preferable to introduce an inert gas such as nitrogen 8 into this area during spinning, from the viewpoint of suppressing nozzle clogging due to oxidative crosslinking. It is even more preferable to introduce a heated inert gas using a heating torch 9. The temperature of the heated inert gas is preferably 100°C to 500°C, and more preferably 200°C to 400°C.

[0054] The spinning speed is not particularly limited and can be set appropriately according to the required fineness, etc., but in order to stably obtain fine fibers, a speed of about 100 m / min or more is preferred, and about 200 m / min or more is more preferred. Furthermore, a speed of about 5000 m / min or less is preferred, and about 4000 m / min or less is more preferred.

[0055] The single-hole discharge rate of the spinning nozzle is preferably 3.0 g / min or less, more preferably 2.8 g / min or less, and even more preferably 2.6 g / min or less. The lower limit of the single-hole discharge rate is not particularly limited, but is preferably 0.05 g / min or more, more preferably 0.1 g / min or more, and even more preferably 0.12 g / min or more.

[0056] The ratio of the diameter D to the length L of the spinning nozzle (L / D) is preferably 3 to 20, and more preferably 4 to 10. Having the ratio of the diameter D to the length L of the spinning nozzle within this range is preferable from the viewpoint of uniform distribution because it appropriately applies pressure loss in the orifice section.

[0057] Examples of PPE used as a raw material include homopolymers having the repeating unit of general formula (1), copolymers containing two or more different repeating units of general formula (1), and copolymers having the repeating unit of general formula (1) and repeating units other than general formula (1). The content of repeating units other than general formula (1) in the copolymer can be as described above. Among these, homopolymers having the repeating unit of general formula (1) are preferred.

[0058] Examples of homopolymers having the repeating unit of the general formula (1) include poly(2,6-dimethyl-1,4-phenylene ether), poly(2,6-diethyl-1,4-phenylene ether), poly(2-methyl-6-ethyl-1,4-phenylene ether), and poly(2,6-dipropyl-1,4-phenylene ether), but among these, poly(2,6-dimethyl-1,4-phenylene ether) is preferred.

[0059] Commercially available poly(2,6-dimethyl-1,4-phenylene ether) products can also be suitably used. Specifically, examples include PPO640, PPO646, and PPOSA120 from SABIC Innovative Plastic, Xylon S201A and Xylon S202A from Asahi Kasei Chemicals Corporation, and LXN035 from Bluestar.

[0060] Furthermore, when melting PPE, the melt viscosity can be reduced by mixing PPE with high Tg and low Tg.

[0061] The glass transition temperature of the PPE component having a high glass transition temperature is preferably 170°C or higher, more preferably 200°C or higher, and even more preferably 210°C or higher. Furthermore, while there is no particular upper limit to the glass transition temperature, 230°C or lower is preferred. Having the glass transition temperature of the raw material PPE within this range is preferable because it allows for the acquisition of PPE fibers with high heat resistance.

[0062] The glass transition temperature of the PPE component having a low glass transition temperature is preferably less than 170°C. Adding PPE with a glass transition temperature of less than 170°C reduces the melt viscosity and improves fluidity.

[0063] The content of PPE having a glass transition temperature of 170°C or higher is preferably 70% by mass or more, more preferably 80% by mass or more, and even more preferably 90% by mass or more, in the PPE component of the raw material. Furthermore, there is no particular upper limit to the content of PPE having a glass transition temperature of 170°C or higher, but it is preferably 100% by mass or less. In the present invention, including PPE with a high glass transition temperature (i.e., high molecular weight) within the above range is preferable because it results in excellent mechanical strength, heat resistance, chemical resistance, flame retardancy, etc., of the resulting PPE molten fibers.

[0064] Furthermore, along with the raw material PPE, the material may also contain resin components and additives other than PPE. The resin components and additives other than PPE are as described above. The content of resin components other than PPE is preferably 5% by mass or less, more preferably 2% by mass or less, and even more preferably none (0% by mass).

[0065] As the extruder equipped with the cylinder and screw, a single-screw extruder or a twin-screw extruder, which are commonly used in this field, can be used. In the present invention, it is preferable to use a twin-screw extruder.

[0066] The peripheral speed of the screw is not particularly limited and can be within the range commonly used in this field. However, when forming fibers using a PPE component having a dislocation structure, the peripheral speed of the screw must be such that the dislocation reaction of the raw material PPE occurs, and is preferably 3.6 m / min or more, more preferably 3.7 m / min or more, and even more preferably 3.8 m / min or more. Furthermore, the upper limit of the peripheral speed of the screw is not particularly limited, but is preferably 94.2 m / min or less. In the present invention, by increasing the screw rotation speed to 3.6 m / min or more, a high shear force can be applied to the raw material PPE in the cylinder, and as a result, the molecular chains of PPE can be cut, and PPE having a dislocation structure can be formed. The formation of the PPE having a dislocation structure makes melt spinning of PPE possible.

[0067] If the temperature inside the cylinder is too low, the fluidity of the resin will be poor, and if it is too high, although the fluidity will improve, foaming will occur due to thermal decomposition of the resin. Therefore, it is necessary to select a processing temperature that strikes a balance between these two factors. For example, the temperature inside the cylinder is preferably between 250°C and 350°C, and more preferably between 280°C and 330°C.

[0068] The surface temperature of the spinning nozzle is not particularly limited, but is preferably 300°C or higher, more preferably 320°C or higher, and even more preferably 330°C or higher. A nozzle surface temperature within this range is preferable because it results in fluidity suitable for spinning.

[0069] According to the manufacturing method of the present invention, by not performing degassing in the melt extrusion process, the amount of gas in the obtained PPE fibers can be made to 1500 ppm or more, and as a result, oxidation can be suppressed. This is thought to be because by not performing degassing, an appropriate amount of amine compounds derived from the raw materials can remain in the PPE fibers, and as a result, oxidation can be suppressed.

[0070] The present invention will be described in more detail below with reference to examples and comparative examples, but the present invention is not limited to the following examples. The evaluation methods for physical properties, etc., in the following examples are as follows.

[0071] (1) Fineness and single filament fineness were measured according to the method described in JIS L-1095 9.4.1. Single filament fineness was calculated by dividing the fineness by the number of filaments.

[0072] (2) Glass transition temperature (Tg) Using a differential scanning calorimetry analyzer (model: DSC-Q100) manufactured by TA Instruments Inc., 2 mg of PPE fiber was measured from 30°C to 250°C in a nitrogen atmosphere at a heating rate of 10°C / min. The temperature at the intersection of the extension of the baseline below the glass transition temperature and the tangent line showing the maximum slope in the transition region was defined as the glass transition temperature (Tg).

[0073] (3) The amount of dislocation structure in PPE fibers at a resonance frequency of 600 MHz １ The measurement was performed using 1H-NMR. A BRUKER NMR spectrometer (model name: AVANCE-NEO600) was used, and the measurement was performed as follows: 10 mg of PPE fiber obtained in the examples and comparative examples was dissolved in deuterated chloroform, and the solution was packed into an NMR tube within 2 hours for measurement. Deuterated chloroform was used as the locking solvent, with a waiting time of 1 second, a data acquisition time of 4 seconds, and 64 integration cycles. Deuterated benzene may also be used as the solvent. The rearrangement structure amount was analyzed as follows: R at the 3 and 5 positions of PPE. １ , R ２ Peaks originating from the proton of the base and R in the dislocation structure ３’ The peak integrals of the divalent groups (such as methylene groups) shown are denoted as A and B, and the rearrangement structure weight was calculated using the following formula: Rearrangement structure weight (mol%) = (B / (A + B)) × 100

[0074] (4) Using a gas pyrolysis gas chromatograph (Py-GC / MS), 2 mg of the obtained thread was added to a sample cup for Py-GC / MS analysis and analyzed under the conditions shown below. (Py-GC / MS analysis conditions) Instrument: PY-2020iD (Frontier LAB) / QP-2010Plus (Shimadzu Corporation) Sample heating conditions: 320°C × 10 min Carrier / heating atmosphere gas: He Column: Ultra ALLOY-5 (MS / HT) (length 30 m, inner diameter 0.25 mm, film thickness 0.25 μm) Column oven temperature: 40°C (2 min) - 10°C / min - 300°C (15 min) Inlet pressure: 80 kPa Inlet temperature: 320°C Split ratio: 30 Ion source: EI method Ion source temperature: 250°C Ionization voltage: 70 eV Interface temperature: 320°C MS measurement mode: SCAN Mass measurement range: m / z 30-550 The quantitative values ​​were calculated by conversion quantification using octamethylcyclotetrasiloxane as a standard substance.

[0075] (5) Average number of bubbles Cut 100 PPE multifilaments and observe the cross-section with an optical microscope (BX53M: manufactured by OLYMPUS) and count the number of bubbles in the fiber cross-section, 1 mm ２ Converted to a number per unit. Average number of bubbles = Number of bubbles in the cross-section of 100 fibers / Cross-sectional area of ​​100 fibers (mm²) ２ )

[0076] (6) Oxidation Initiation Temperature (IOT) Using a TG-DTA (Hitachi High-Tech Corporation, TGDTA7200), the sample (10 mg) was placed in an aluminum pan and heated from 50°C to 450°C at a rate of 1°C / min in an air atmosphere (air flow rate: 200 mL / min). The moving average (n=30) of the obtained DTG (μg / °C) was plotted against temperature, and the temperature at which DTG = -2 was defined as the oxidation initiation temperature.

[0077] (7) Peripheral speed of the screw The peripheral speed of the screw was determined by the following formula: Peripheral speed of the screw (m / min) = Screw diameter (mm) × 0.00314 × Screw rotation speed (rpm)

[0078] Example 1 Poly(2,6-dimethyl-1,4-phenylene ether) (LXN035, glass transition temperature (Tg): 213°C, viscosity: 0.37 dL / g, manufactured by Bluestar) was extruded using a twin-screw extruder manufactured by Technovel Co., Ltd. (product name: KZW15TW-30MG). The twin-screw extruder had four cylinder zones, and the cylinders from the hopper side were designated as cylinder 1, 2, 3, and 4. Cylinder 1 was set to 260°C, cylinders 2-4 and the cylinder head were set to 300°C, and the screw rotation speed was set to 700 rpm, resulting in a screw peripheral speed of 33.0 m / min. Cylinder 3 was not fitted with a vent and no degassing was performed.

[0079] A gear pump was installed downstream of the extruder, and the polymer was extruded through a metal nonwoven fabric filter (product name: NF-07, manufactured by Nippon Seisen Co., Ltd.) into a nozzle (nozzle hole diameter: 0.5 mm, nozzle hole land length: 4.0 mm, number of nozzle holes: 48) (total discharge rate: 13 g / min). The polymer discharged from the nozzle was wound up at a spinning speed of 246 m / min. The single filament fineness of the obtained PPE fiber was 22 dtex, the glass transition temperature was 209°C, and the gas content was 2000 ppm. The content of amine compounds (dibutylamine, N-butylidene-1-butylamine) in the obtained PPE fiber was 1100 ppm relative to the total amount of polyphenylene ether fiber.

[0080] Examples 2-3 PPE fibers were obtained in the same manner as in Example 1, except that the peripheral speed of the screw was changed to the peripheral speed shown in Table 1. The gas content of the obtained fibers was 1800 ppm (Example 2), 1900 ppm (Example 3), and 1800 ppm (Example 4).

[0081] Example 4 Poly(2,6-dimethyl-1,4-phenylene ether) (LXN035, glass transition temperature (Tg): 213°C, viscosity: 0.37 dL / g, manufactured by Bluestar) was extruded using a single-screw extruder. The single-screw extruder had four cylinder zones, which were designated as cylinders 1, 2, 3, and 4 from the hopper side. Cylinder 1 was set to 260°C, cylinders 2-4 and the cylinder head were set to 280°C, and the screw rotation speed was set to 5 rpm, resulting in a screw peripheral speed of 0.47 m / min. A vent was attached to cylinder 3, but the vent was closed and no degassing was performed.

[0082] Downstream of the extruder, a gear pump was installed, and the polymer was extruded through a metal nonwoven fabric filter (product name: NF-07, manufactured by Nippon Seisen Co., Ltd.) to a nozzle (nozzle hole diameter: 0.5 mm, nozzle hole land length: 2.0 mm, number of nozzle holes: 24) (total discharge volume: 13.8 g / min). Nitrogen gas at 150°C was introduced directly below the nozzle. The polymer discharged from the nozzle was wound up at a spinning speed of 261 m / min.

[0083] Comparative Example 1 Poly(2,6-dimethyl-1,4-phenylene ether) (LXN035, glass transition temperature (Tg): 213°C, viscosity: 0.37 dL / g, manufactured by Bluestar) was extruded using a twin-screw extruder manufactured by Technovel Co., Ltd. (product name: KZW15TW-30MG). The twin-screw extruder had four cylinder zones, and the cylinders from the hopper side were designated as cylinders 1, 2, 3, and 4. Cylinder 1 was set to 260°C, cylinders 2-4 and the cylinder head were set to 320°C, and the screw rotation speed was set to 700 rpm, resulting in a screw peripheral speed of 33.0 m / min. A vent was attached to cylinder 3, and the vent was evacuated.

[0084] Downstream of the extruder, a gear pump was installed, and the polymer was extruded through a metal nonwoven fabric filter (product name: NF-07, manufactured by Nippon Seisen Co., Ltd.) into a nozzle (nozzle hole diameter: 0.80 mm, nozzle hole land length: 4.0 mm, number of nozzle holes: 72) (total discharge volume: 66 g / min). The polymer discharged from the nozzle was wound up at a spinning speed of 417 m / min. The obtained PPE fiber had a single filament fineness of 22 dtex, a glass transition temperature of 208°C, and a gas content of 980 ppm.

[0085] Comparative Examples 2 and 3: PPE fibers were obtained in the same manner as in Comparative Example 1, except that the discharge rate was changed during the formation of the PPE fibers. The gas content of the obtained fibers was 950 ppm (Comparative Example 2) and 890 ppm (Comparative Example 3).

[0086]

[0087] Examples 1 to 4 showed a high gas content in the PPE fibers, resulting in a high oxidation onset temperature and excellent oxidation resistance. On the other hand, Comparative Examples 1 to 3 showed a low gas content in the PPE fibers, resulting in a low oxidation onset temperature and easily oxidized (poor oxidation resistance) PPE fibers.

[0088] 1. Hopper 2. Extruder 3. Gear pump 4. Filter media 5. Spinning nozzle 6. Filter 7. Insulated space 8. Inert gas introduction 9. Heating torch 10. Degassing vent

Claims

1. A polyphenylene ether fiber containing a polyphenylene ether component, characterized in that the amount of gas generated when the polyphenylene ether fiber is heated at 320°C for 10 minutes is 1500 ppm or more.

2. The polyphenylene ether fiber according to claim 1, characterized in that the oxidation onset temperature (IOT) of the polyphenylene ether fiber is 206°C or higher.

3. The polyphenylene ether fiber according to claim 1, characterized in that the polyphenylene ether fiber contains an amine compound.

4. The polyphenylene ether fiber according to claim 3, characterized in that the content of the amine compound is 500 ppm or more relative to the total amount of polyphenylene ether fiber.

5. The polyphenylene ether fiber according to claim 1, characterized in that the polyphenylene ether component has a rearrangement structure in which it is connected by ortho bonds in a repeating unit that is continuous by para bonds.

6. The repeating unit formed by the para-position bond is given by the following general formula (1): (In the formula, R １ , R ２ Each is independently a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms which may have substituents, and R ３ Each of these is a repeating unit represented by (which independently represents a hydrocarbon group having 1 to 10 carbon atoms, which may have substituents), and the rearrangement structure is represented by the following general formula (2): (In the formula, R １ , R ２ Each is independently a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms which may have substituents, and R ３ Each is independently a hydrocarbon group having 1 to 10 carbon atoms, which may have substituents, and R ３’ is the aforementioned R ３ The polyphenylene ether fiber according to claim 5, characterized in that it has a structure represented by (representing a divalent group from which one hydrogen atom has been removed).

7. The polyphenylene ether fiber according to claim 6, characterized in that the amount of dislocation in the polyphenylene ether component having the dislocation structure is 0.05 mol% or more relative to the total polyphenylene ether structural units in the polyphenylene ether component.

8. The polyphenylene ether fiber according to claim 1, characterized in that the content of the polyphenylene ether component is 95% by mass or more of the total components forming the fiber.

9. An activated carbon fiber characterized by using polyphenylene ether fibers according to any one of claims 1 to 8 as raw cotton.

10. A method for producing polyphenylene ether fibers according to any one of claims 1 to 8, comprising the steps of melting and extruding polyphenylene ether, which is a raw material, using an extruder equipped with a cylinder and a screw, and spinning the molten polyphenylene ether by extruding it from a spinning nozzle, wherein degassing is not performed in the melting and extruding step.

Images