WO2022259843A1 - モノフィラメントおよびその製造方法 - Google Patents

モノフィラメントおよびその製造方法 Download PDF

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Publication number
WO2022259843A1
WO2022259843A1 PCT/JP2022/020954 JP2022020954W WO2022259843A1 WO 2022259843 A1 WO2022259843 A1 WO 2022259843A1 JP 2022020954 W JP2022020954 W JP 2022020954W WO 2022259843 A1 WO2022259843 A1 WO 2022259843A1
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Prior art keywords
monofilament
draw ratio
less
knotted
drawing step
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PCT/JP2022/020954
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English (en)
French (fr)
Japanese (ja)
Inventor
晴紀 目代
渉 古川
崇士 正木
義紀 鈴木
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Kureha Corp
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Kureha Corp
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Priority to US18/566,847 priority Critical patent/US20240271331A1/en
Priority to EP22820025.9A priority patent/EP4353880A4/en
Priority to CN202280033786.XA priority patent/CN117280085A/zh
Priority to JP2023527594A priority patent/JP7556148B2/ja
Publication of WO2022259843A1 publication Critical patent/WO2022259843A1/ja
Anticipated expiration legal-status Critical
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    • D—TEXTILES; PAPER
    • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
    • D01F—CHEMICAL FEATURES IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS; APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OF CARBON FILAMENTS
    • D01F6/00—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof
    • D01F6/58—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from homopolycondensation products
    • D01F6/60—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from homopolycondensation products from polyamides
    • D—TEXTILES; PAPER
    • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
    • D01D—MECHANICAL METHODS OR APPARATUS IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS
    • D01D10/00—Physical treatment of artificial filaments or the like during manufacture, i.e. during a continuous production process before the filaments have been collected
    • D01D10/02—Heat treatment
    • D—TEXTILES; PAPER
    • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
    • D01D—MECHANICAL METHODS OR APPARATUS IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS
    • D01D5/00—Formation of filaments, threads, or the like
    • D01D5/12—Stretch-spinning methods
    • D—TEXTILES; PAPER
    • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
    • D01D—MECHANICAL METHODS OR APPARATUS IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS
    • D01D5/00—Formation of filaments, threads, or the like
    • D01D5/12—Stretch-spinning methods
    • D01D5/16—Stretch-spinning methods using rollers, or like mechanical devices, e.g. snubbing pins

Definitions

  • the present invention relates to a monofilament and its manufacturing method.
  • Polyamide 4 (hereinafter also referred to as "PA4") is expected to be put into practical use as a bioplastic, and many spinning methods are being studied.
  • One of the properties required for PA4 monofilaments is to have high tensile strength.
  • Spinning methods for producing PA4 monofilaments having such high tensile strength include a solution spinning method using formic acid (see, for example, Patent Document 1), a gel spinning method using an ionic liquid, and an inorganic salt.
  • the melt spinning method used (see, for example, Patent Document 2) is known.
  • An object of one aspect of the present invention is to realize a PA4 monofilament that exhibits high tensile properties even when knotted.
  • a monofilament according to an aspect of the present invention is a polyamide 4 monofilament, and the monofilament has a scattering vector of 0.02 nm ⁇ 1 or more and 0.04 nm ⁇ by small-angle X-ray scattering measurement.
  • the average value of the ratio I2/I1 of the normalized scattering intensity I2 in the equatorial direction to the normalized scattering intensity I1 in the meridian direction in the range of 1 or less is 5 or less, and the birefringence of the monofilament is 50 ⁇ 10 -3 or more.
  • a method for producing a monofilament according to an aspect of the present invention is a method for producing a monofilament of polyamide 4 by drawing an undrawn yarn of polyamide 4, wherein A drawn yarn is drawn by a first drawing step in which the drawing temperature is 40° C. or higher and the drawing ratio is 2.5 times or more and 3.5 times or less, and the first drawing step is performed. and a second drawing step of drawing the primarily drawn yarn of polyamide 4 by wet heat drawing at a drawing temperature of 80 ° C. or higher and 120 ° C. or lower and a specific draw ratio, wherein the specific draw ratio is the above.
  • FIG. 1 is a photograph of a two-dimensional image of small-angle X-ray scattering (SAXS) in the monofilament of Example 1 of the present invention
  • FIG. 4 is a photograph of a two-dimensional image of small-angle X-ray scattering (SAXS) in the monofilament of Comparative Example 1 of the present invention
  • PA4 polyamide 4
  • PA4 is a polymer compound having a structural unit represented by the following formula (1). x in the following formula is 4.
  • PA4 may be the only polymeric compound that constructs the monofilament fiber structure.
  • components other than PA4 may be further contained as long as the effects of the present embodiment can be obtained.
  • Such other ingredients may be one or more and examples include reinforcing agents, plasticizers, lubricants and stabilizers.
  • the other component may contain a polymer compound other than PA4. The other component is appropriately used in an amount such that the effect of the other component is further exhibited.
  • the monofilaments of embodiments of the present invention are PA4 monofilaments.
  • the monofilaments of embodiments of the present invention have a specific ratio of scattered intensities measured by small angle X-ray scattering (SAXS). That is, the normalized scattering intensity I2 in the equator direction with respect to the normalized scattering intensity I1 in the meridian direction in the range of 0.02 nm ⁇ 1 or more and 0.04 nm ⁇ 1 or less in the scattering vector q by small-angle X-ray scattering measurement of the monofilament
  • SAXS small angle X-ray scattering
  • the average value of I2/I1 is the normalized scattering intensity I1 in the meridional direction and the normalized scattering intensity I1 in the equatorial direction obtained for each scattering vector q in steps of 0.000241 in the range of 0.02 nm ⁇ 1 to 0.04 nm ⁇ 1 It is the average value of the ratio I2/I1 to the normalized scattering intensity I2.
  • the normalized scattering intensity I2 in the equatorial direction represents voids in the monofilament (small cavities in the monofilament). A larger value of I2 indicates a larger amount of voids in the monofilament.
  • the meridional normalized scattering intensity I1 represents scattering other than voids in the monofilament. The fact that the average value of the ratio I2/I1 is 5 or less indicates that the voids in the monofilament are sufficiently suppressed, and the same tensile properties are exhibited even when knotted as when not knotted. A PA4 monofilament having an average value of the ratio I2/I1 of 5 or less has sufficiently high tensile properties even when knotted.
  • the ratio I2/I1 is preferably as low as possible from the viewpoint of enhancing the tensile properties of the PA4 monofilament when knotted. For these reasons, the ratio I2/I1 is more preferably in the range of 1 or more and 2 or less.
  • the above I2 and I1 can be measured using a known small-angle X-ray scattering measurement device.
  • the above ratio I2/I1 can be achieved by a manufacturing method including a first stretching step and a second stretching step, which will be described later. For example, by lowering the stretching ratio in the second stretching step, , I2 tend to be small.
  • the monofilaments of embodiments of the invention have a specific birefringence. That is, the birefringence of the monofilament is 50 ⁇ 10 ⁇ 3 or more.
  • the birefringence of a monofilament is a measure of the degree of orientation of the polymer chains of the polymer compound that constitutes the monofilament with respect to the fiber axis direction.
  • the degree of orientation increases as the absolute value of the birefringence increases. That the birefringence of the monofilament is 50 ⁇ 10 ⁇ 3 or more means that the monofilament has been subjected to the drawing process.
  • the birefringence is preferably 50 ⁇ 10 -3 or more, more preferably 55 ⁇ 10 -3 or more, and further preferably 60 ⁇ 10 -3 or more, from the viewpoint of improving the tensile properties of the monofilament. preferable.
  • the birefringence may be 90 ⁇ 10 ⁇ 3 or less from the viewpoint of exhibiting sufficiently high tensile properties when the monofilament is knotted.
  • the above birefringence can be measured, for example, by retardation measurement using a polarizing microscope equipped with a Berek compensator and using a sodium lamp as a light source. Moreover, the birefringence tends to increase as the draw ratio in the manufacturing method described later is increased.
  • the knotted tensile strength of the monofilament of the embodiment of the present invention is preferably 550 MPa or more from the viewpoint of achieving sufficient tensile strength in applications where the monofilament can be used in a knotted state. Applications that can be used in a knotted state are, for example, fishing lines.
  • the tensile strength at the time of knotting can be appropriately determined according to the use of the monofilament.
  • the tensile strength at knotting is preferably high from the viewpoint of preventing the monofilament from breaking at the knotting point when pulled, more preferably 550 MPa or more, and further preferably 600 MPa or more.
  • the tensile strength at knotting may be within a range that can be achieved with a PA4 monofilament, and from this point of view, the tensile strength at knotting may be 1000 MPa or less.
  • the tensile strength of a monofilament when knotted can be measured using a known device capable of performing fiber tensile tests.
  • the tensile strength of the monofilament when knotted can be achieved by a manufacturing method including a first drawing step and a second drawing step, which will be described later.
  • the knotting tensile strength tends to increase as the density of the undrawn yarn is lowered.
  • the monofilament of the embodiment of the present invention prefferably has a tensile elongation of 10% or more when knotted from the viewpoint of preventing breakage when used in a knotted state.
  • the tensile elongation at knotting can be appropriately determined according to the use of the monofilament, and from the above viewpoint, it is more preferably 15% or more, and further preferably 20% or more.
  • the tensile elongation at the time of knotting should be within a range that can be achieved with the PA4 monofilament, and from this point of view, the tensile elongation at the time of knotting may be 50% or less.
  • the tensile elongation of a monofilament at the time of knotting can be measured using a known device capable of performing fiber tensile tests.
  • the tensile elongation of the monofilament at the time of knotting can be achieved by a manufacturing method including the first drawing step and the second drawing step described later. Further, the tensile elongation at the time of knotting tends to decrease by increasing the draw ratio in the production method described later, and tends to increase by decreasing the density of the undrawn yarn.
  • the thread diameter of the monofilament of the embodiment of the present invention is preferably 400 ⁇ m or less from the viewpoint of sufficiently enhancing the tensile properties of the monofilament when knotted. If the yarn diameter exceeds 400 ⁇ m, the moisture absorption in the second drawing step of the manufacturing method described below may be insufficient, and the tensile properties at the time of knotting may be insufficient.
  • the thread diameter of the monofilament is more preferably 300 ⁇ m or less, further preferably 200 ⁇ m or less, from the viewpoint of achieving sufficient moisture absorption of the monofilament in the second drawing step.
  • the thread diameter of the monofilament may be within a range that can be achieved with the PA4 monofilament depending on the use of the monofilament, but may be 50 ⁇ m or more from the viewpoint of sufficiently performing the above moisture absorption.
  • the thread diameter of the monofilament can be measured by a known technique for measuring the fiber diameter, for example, it can be measured by a known method of sandwiching the fiber and measuring the thread diameter of the fiber.
  • the thread diameter of the monofilament tends to be reduced by increasing the draw ratio in the manufacturing method described below.
  • the monofilament of the embodiment of the present invention only needs to have the physical properties described above, and may further have physical properties other than those described above as long as the effects of the present embodiment described above are achieved.
  • the weight average molecular weight of PA4 in the present embodiment is not limited, but from the viewpoint of sufficiently expressing physical properties peculiar to PA4 such as mechanical properties and heat resistance in monofilaments, it is preferably 20,000 or more. , more preferably 30,000 or more, and even more preferably 35,000 or more. Moreover, the weight average molecular weight of PA4 may be within a range in which a monofilament of PA4 can be obtained.
  • a monofilament according to an embodiment of the present invention can be manufactured by the manufacturing method described below.
  • the monofilament of the embodiment of the present invention is produced by drawing an undrawn yarn of polyamide 4 through the following first drawing step and second drawing step. By carrying out such a two-stage drawing process, it is possible to produce a PA4 monofilament having excellent tensile properties when knotted as described above.
  • An undrawn yarn of polyamide 4 is a monofilament produced by spinning from polyamide 4 and is a monofilament that is not substantially drawn.
  • the undrawn yarn is preferably amorphous from the viewpoint of enhancing the tensile properties of the finally produced monofilament when knotting. From this point of view, it is preferable that the density of the undrawn yarn is low. From the viewpoint of realizing the aforementioned tensile properties of the monofilament when knotted (the tensile strength when knotted is 550 MPa or more and the tensile elongation when knotted is 10% or more), the density of the undrawn yarn is 1.225 g/cm 3 or less. and more preferably 1.223 g/cm 3 or less.
  • the density of the undrawn yarn can be appropriately determined within a range in which the tensile properties at the time of knotting can be expressed according to the application of the monofilament. or less than 1.250 g/cm 3 .
  • the density of the monofilament correlates with the degree of crystallinity of the monofilament, and there is a tendency that the lower the density, the lower the degree of crystallinity. For example, a density of the monofilament of 1.230 g/cm 3 corresponds to a degree of crystallinity of the monofilament of approximately 10%.
  • the density of undrawn yarn can be obtained by a method called the "density gradient method".
  • the density of the undrawn yarn can be adjusted by the cooling conditions of the fibrous melt extrudate of PA4 obtained by melt spinning.
  • the density of undrawn yarn tends to decrease as the cooling temperature is lower or as the cooling time is longer.
  • the first drawing step is a step of drawing an undrawn yarn of polyamide 4 by dry heat drawing under conditions of a drawing temperature of 40° C. or higher and a draw ratio of 2.5 to 3.5 times. However, when the total draw ratio described later is 3.5 times, the draw ratio in the first drawing step is less than 3.5 times.
  • the first stretching step can be carried out by a known technique capable of carrying out stretching under such conditions. By drawing the undrawn yarn under the above conditions to some extent prior to the second drawing step, it is possible to prevent drawing breakage during wet heat drawing.
  • the stretching temperature is 40°C or higher. If the drawing temperature in the first drawing step is too low, whitening may occur in the monofilament.
  • the drawing temperature in the first drawing step is preferably 40° C. or higher, more preferably 50° C. or higher, from the viewpoint of preventing whitening of the monofilament.
  • the stretching temperature in the first stretching step is preferably 100° C. or lower, more preferably 80° C. or lower.
  • the drawing temperature in the first drawing step is more preferably in the range of 60 ⁇ 5° C., more preferably 60° C., from the viewpoint of preventing whitening of the monofilament and developing the desired tensile properties at the time of knotting. is most preferred.
  • the stretching ratio is 2.5 times or more and 3.5 times or less. If the draw ratio in the first drawing step is too low, necking will remain in the undrawn PA yarn that has been subjected to the first drawing step (primary drawn yarn), and local necking will occur in the subsequent second drawing step. Deformation may occur and the diameter of the monofilament may become uneven. From the viewpoint of obtaining monofilaments having a uniform thread diameter, the draw ratio in the first drawing step is preferably 2.5 times or more, more preferably 2.8 times or more.
  • the draw ratio in the first drawing step is preferably 3.5 times or less, more preferably 3.2 times or less. From the viewpoint of having a uniform yarn diameter and suppressing the generation of voids, the draw ratio in the first drawing step is more preferably within the range of 3 ⁇ 0.1 times, most preferably 3 times. preferable.
  • the form of drawing in the first drawing step is dry heat drawing.
  • the dry heat drawing referred to here means drawing a monofilament in a gas phase (for example, air) whose temperature is controlled to the drawing temperature described above.
  • the humidity in the first stretching step is not limited, and may be, for example, 80% or less in terms of relative humidity.
  • the second drawing step is a step of drawing the primarily drawn yarn of polyamide 4 produced in the first drawing step by wet heat drawing under the conditions of a drawing temperature of 80° C. or more and 120° C. or less and a draw ratio of 4 times or more. is.
  • the second stretching step can be carried out by a known technique capable of carrying out stretching under such conditions.
  • the first drawn yarn is drawn in a hygroscopic and softened state, thereby producing a PA4 monofilament having excellent tensile properties at the time of knotting as described above.
  • the drawing temperature in the second drawing step is 80°C or higher and 120°C or lower. If the drawing temperature in the second drawing step is too low, the moisture absorption of the primarily drawn yarn may be insufficient, and the resulting monofilament may have insufficient tensile properties when knotted.
  • the drawing temperature in the second drawing step is preferably 85° C. or higher, more preferably 90° C. or higher, from the viewpoint of sufficiently absorbing moisture in the primary drawn yarn.
  • the drawing temperature in the second drawing step can be appropriately set within a range where the drawing atmosphere can be realized with steam.
  • the stretching temperature in the second stretching step is preferably 110° C. or lower, more preferably 105° C. or lower, from the viewpoint of being able to set the stretching atmosphere.
  • the drawing temperature in the second drawing step is in the range of 100 ⁇ 3° C. from the viewpoints of facilitating the construction of the drawing apparatus and sufficiently absorbing moisture from the first drawn yarn. is more preferable, and 100° C. is most preferable.
  • the draw ratio in the second drawing step is 3.5 times or more.
  • the draw ratio of the second drawing step in the embodiment of the present invention is the ratio at which the undrawn yarn is finally drawn from both the first drawing step and the second drawing step ("total draw ratio" is also called).
  • the draw ratio in the second drawing step alone is appropriately determined according to the draw ratio in the first drawing step and the total draw ratio.
  • the draw ratio in the second drawing step is usually higher than the draw ratio in the first drawing step. In this case, if the drawing step is only two stages, the total draw ratio is equal to the draw ratio in the second drawing step. be the same as
  • the draw ratio in the second drawing step is preferably a draw ratio at which the total draw ratio is 3.8 times or more, and a draw ratio which is 4 times or more. is more preferred.
  • the draw ratio in the second drawing step is preferably a draw ratio at which the total draw ratio is 5 times or less, and the total draw ratio is 4.5 times or less. It is more preferable that the draw ratio is From the viewpoint of sufficiently expressing the tensile properties of the monofilament at the time of knotting and sufficiently suppressing the generation of voids, the draw ratio in the second drawing step is within the range of 4 ⁇ 0.3 times as a total draw ratio. The draw ratio is more preferable, and the draw ratio is most preferably 4 times as the total draw ratio.
  • the form of stretching in the second stretching step is wet heat stretching.
  • the wet heat drawing referred to here means drawing a monofilament in a steam atmosphere whose temperature is controlled to the drawing temperature described above.
  • the humidity in the second stretching step is not limited, and may be, for example, 90% or more in terms of relative humidity.
  • the drawing time in the second drawing step is preferably long from the viewpoint of sufficiently wetting the first drawn yarn. From such a viewpoint, the stretching time is preferably 5 seconds or longer, more preferably 8 seconds or longer, and even more preferably 10 seconds or longer. On the other hand, the drawing time in the second drawing step is preferably short from the viewpoint of monofilament productivity. From such a viewpoint, the stretching time is preferably 60 seconds or less, more preferably 45 seconds or less, and even more preferably 30 seconds or less.
  • the diameter of the primary drawn yarn is preferably small from the viewpoint of sufficiently wetting the primary drawn yarn in the second drawing step.
  • the yarn diameter of the primary drawn yarn is 500 ⁇ m or less. It is preferably 400 ⁇ m or less, and even more preferably 300 ⁇ m or less.
  • the method for producing a monofilament according to the embodiment of the present invention may further include steps other than the above-described first drawing step and second drawing step within the range in which the effect of the embodiment of the present invention can be obtained.
  • the manufacturing method may further include a spinning step to produce an undrawn yarn of PA4.
  • the form of the spinning process is so-called melt spinning, and the spinning process includes a melt extrusion process in which a melt-kneaded product of PA4 is extruded to form a fibrous melt extrudate of PA4, and a melt extrusion process. a cooling step of cooling the molten extrudate in a coolant liquid.
  • Such a spinning process can be carried out by known melt spinning techniques that produce undrawn yarns with liquid cooling.
  • the cooling temperature is preferably low from the viewpoint of lowering the density of the undrawn yarn, more specifically, it is preferably ⁇ 10° C. or less, and more preferably ⁇ 15° C. or less. It is preferably ⁇ 20° C. or lower, and more preferably ⁇ 20° C. or lower.
  • the cooling temperature can be appropriately determined according to the type of refrigerant liquid and production cost, and when the refrigerant liquid is a non-polar solvent described later, it may be ⁇ 60° C. or higher from the viewpoint of cost.
  • the cooling time is preferably long, more specifically, preferably 0.1 seconds or more, and 0.2 seconds or more, from the viewpoint of reducing the density of the undrawn yarn. is more preferable, and 0.3 seconds or longer is even more preferable.
  • the cooling time is preferably short from the viewpoint of productivity, and from such a viewpoint, it is preferably 5 seconds or less, more preferably 3 seconds or less, and even more preferably 2 seconds or less.
  • the coolant liquid is preferably substantially inert to the PA4 melt extrudate from the viewpoint of preventing surface roughness or whitening of the undrawn yarn.
  • substantially inert means that it does not substantially act on the melt extrudate, more specifically, it is poorly soluble or insoluble in PA4, and the melt extrudate of PA4 and having no permeability.
  • Such a refrigerant liquid is preferably a non-polar solvent. Examples of nonpolar solvents include silicone oil, hexane, nonane, decane, ethylcyclohexane, isopropylcyclohexane, toluene and p-cymene.
  • the fibrous molten extrudate is usually pulled at a speed higher than the discharge speed of the molten extrudate, cooled, and supplied to the subsequent drawing device.
  • the pulling of the melt extrudate for supplying from the melt extrusion process to the cooling process and the subsequent drawing process is not included in the drawing process, and is appropriately within the range where the effect of the present embodiment can be obtained. can be set to
  • an additional drawing step that does not substantially generate voids may be performed after the second drawing step.
  • a further stretching step is performed at a higher temperature (for example, 200° C.) and a moderate stretching ratio (for example, a final stretching ratio (total stretching ratio) including a further stretching step of 5 times). It can be carried out by hot drawing.
  • This further drawing step is advantageous from the viewpoint of further enhancing the tensile properties of the monofilament.
  • a method for manufacturing a monofilament according to an embodiment of the present invention includes the above-described first drawing step and second drawing step.
  • the PA4 monofilament produced by the production method of the present embodiment including these drawing steps has higher tensile properties when knotted than the PA4 monofilament produced through a drawing step other than these drawing steps. .
  • the formation of voids in the monofilament is suppressed, resulting in a monofilament with improved tensile properties during knotting. More specifically, according to embodiments of the present invention, monofilaments with high knotting tensile strength and tensile elongation can be achieved.
  • the moisture absorption amount of the primarily drawn yarn is reduced in the first drawing step, and then wet heat drawing is performed in the second drawing step.
  • the primarily drawn yarn absorbs moisture sufficiently and is further drawn in that state, thereby sufficiently suppressing the generation of voids and crystallization.
  • the stress generated in the monofilament by drawing usually increases, and voids are likely to form.
  • voids stress tends to be concentrated when the monofilament is knotted, and the monofilament tends to break from there as a starting point. Therefore, when the second drawing step is performed by dry heat drawing, the tensile properties at the time of knotting tend to decrease.
  • the drawing in both the first drawing step and the second drawing step, the drawing is performed at a sufficiently high draw ratio so as not to cause breakage of the drawing. Therefore, the strength of the monofilament is sufficiently developed.
  • the tensile strength at knotting is always smaller than the tensile strength at straight line. Therefore, when the draw ratio in the drawing step is lowered, the straight tensile strength of the obtained monofilament is lowered. Therefore, when the draw ratio is low, the knotted tensile strength of the obtained monofilament is also low.
  • the PA4 monofilament produced by the production method of the present embodiment can be identified by the fact that voids are substantially absent and traces of stretching.
  • the presence or absence of voids can be confirmed by a small-angle X-ray scattering method, and traces of stretching can be confirmed by the degree of molecular orientation of PA4.
  • the diameter of the primary drawn yarn to be subjected to the second drawing step when the diameter of the monofilament is sufficiently small, the diameter of the primary drawn yarn to be subjected to the second drawing step also becomes sufficiently small according to the draw ratio in the second drawing step. , the primary drawn yarn can be drawn in a sufficiently wet state in the second drawing step.
  • the diameter of the monofilament is 400 ⁇ m or less, it is advantageous to realize the aforementioned tensile properties of the monofilament when knotted (the tensile strength when knotted is 550 MPa or more and the tensile elongation when knotted is 10% or more). is.
  • a lower density of monofilaments is advantageous in terms of enhancing tensile properties when knotted, and a lower density of undrawn yarns leads to a lower density of monofilaments (drawn yarns). It is advantageous from the viewpoint of From this point of view, it is advantageous for the density of the undrawn yarn to be 1.225 g/cm 3 or less from the viewpoint of exhibiting the above-mentioned tensile properties when the monofilament is knotted.
  • the monofilament of the embodiment of the present invention is a polyamide 4 monofilament, and the monofilament has a scattering vector of 0.02 nm ⁇ 1 or more and 0.04 nm ⁇ 1 by small-angle X-ray scattering measurement.
  • the ratio I2/I1 of the normalized scattering intensity I2 in the equatorial direction to the normalized scattering intensity I1 in the meridian direction is 5 or less
  • the average birefringence of the monofilament is 50 ⁇ 10 ⁇ 3 or more.
  • the method for producing a monofilament in the embodiment of the present invention is a method for producing a monofilament of polyamide 4 by drawing an undrawn yarn of polyamide 4, wherein the undrawn yarn of polyamide 4 is drawn at a drawing temperature of 40 ° C. or higher. and a draw ratio of 2.5 times or more and 3.5 times or less by dry heat drawing; and a second stretching step of stretching by wet heat stretching at a temperature of 80° C. or higher and 120° C. or lower at a specific draw ratio.
  • the specific draw ratio is a draw ratio at which the total draw ratio, which is the final draw ratio for the undrawn yarn in both the first drawing step and the second drawing step, is 3.5 times or more. However, when the total draw ratio is 3.5 times, the draw ratio in the first drawing step is less than 3.5 times.
  • the tensile strength of the monofilament when knotted may be 550 MPa or more, and the tensile elongation of the monofilament when knotted may be 10% or more. This configuration is even more effective from the viewpoint of realizing a monofilament having sufficient tensile strength in applications that can be used in a knotted state.
  • the monofilament thread diameter may be 400 ⁇ m or less. This configuration is much more effective from the viewpoint of sufficiently enhancing the tensile properties of the monofilament when knotted.
  • the undrawn yarn may have a density of 1.225 g/cm 3 or less. This configuration is much more effective from the viewpoint of achieving the aforementioned tensile properties of the monofilament when knotted (tensile strength when knotted is 550 MPa or more and tensile elongation when knotted is 10% or more).
  • Example 1 At room temperature, 2 mol % of potassium tert-butoxide was added to ⁇ -pyrrolidone and stirred in a polymerization vessel. After dissolving potassium tert-butoxide, 2 mol % of tetramethylammonium chloride as a polymerization aid and 0.1 mol % of N,N'-adipyldipyrrolidone as an initiator were added. After the addition, the system became cloudy and soon became difficult to stir. After 72 hours from stopping the stirring, the lumps formed in the flask were taken out and crushed. Unreacted substances and low-molecular-weight substances were washed with acetone. Powdered PA4 was obtained by drying the washed pulverized product. The weight average molecular weight (Mw) of PA4 obtained was 140,000.
  • the Mw of PA4 was measured using the following procedure, analyzer and conditions. [Measurement procedure] After dissolving 10 mg of the PA4 sample obtained as described above in hexafluoroisopropanol (HFIP) in which sodium trifluoroacetate was dissolved at a concentration of 5 mM to make 10 cm 3 , the solution was filtered through a membrane filter to obtain a sample solution. rice field. 10 ⁇ L of this sample solution was injected into the analyzer shown below, and the weight average molecular weight of PA4 was measured under the measurement conditions described later. In the present specification, "-" indicates a range of values including both ends of the range.
  • HFIP hexafluoroisopropanol
  • GPC device Tosoh HLC-8420GPC [Measurement condition]
  • F) dn/dc 0.240
  • PA4 is molded into a fiber by melt extrusion at a temperature of 265 ° C., and the obtained fibrous melt extrudate is volatile silicone oil ("KF-995", manufactured by Shin-Etsu Silicone Co., Ltd.) at -20 ° C. immediately after molding. It cooled and solidified by passing through the bath for 0.3 seconds. An undrawn yarn of PA4 was thus produced. When the density of the undrawn yarn was determined by the method described below, the density of the undrawn yarn was 1.220 g/cm 3 .
  • the density of the undrawn yarn was obtained by the density gradient method. Six kinds of mixed solvents were used as the solvent, the density of which was adjusted between 1.20 and 1.30 g/cm 3 in increments of 0.02 by changing the mixing ratio of heptane and carbon tetrachloride.
  • the produced undrawn yarn was drawn by dry heat drawing at a draw temperature of 60°C and a draw ratio of 3.0 times.
  • the humidity of the dry heat drawing atmosphere was 10% RH or less.
  • the produced primary drawn yarn was drawn by wet heat drawing at a drawing temperature of 100° C. and a total drawing ratio of 4.0 times.
  • the humidity of the atmosphere for wet heat stretching was 100% RH.
  • the thread diameter of the manufactured monofilament was measured by sandwiching the monofilament with a micrometer. For each of the five randomly selected monofilaments, the yarn diameter was measured at any one point in the length direction, the average value of the obtained measured values was obtained, and it was taken as the monofilament yarn diameter.
  • the thread diameter of the monofilament was 168 ⁇ m.
  • Example 2 A monofilament was produced in the same manner as in Example 1, except that the draw ratio of the primary drawn yarn in the wet heat drawing of the secondary drawing was changed to a total draw ratio of 4.8 times.
  • the thread diameter of the monofilament was 147 ⁇ m.
  • Example 3 A monofilament was produced in the same manner as in Example 1, except that the temperature of the silicone oil bath for cooling the fibrous melt extrudate was changed to 40°C. The density of the undrawn yarn was 1.239 g/cm 3 .
  • Example 4 A monofilament was produced in the same manner as in Example 1, except that the primary draw ratio of the undrawn yarn was changed to 2.5 times.
  • Example 5 A monofilament was produced in the same manner as in Example 1, except that the primary draw ratio of the undrawn yarn was changed to 3.5 times.
  • Example 6 A monofilament was produced in the same manner as in Example 1, except that the primary drawing temperature of the undrawn yarn was changed to 50°C.
  • Example 7 A monofilament was produced in the same manner as in Example 1, except that the primary drawing temperature of the undrawn yarn was changed to 100°C.
  • Example 2 A monofilament was produced in the same manner as in Example 3, except that the secondary drawing temperature was changed to 200° C. and the primary drawn yarn was secondarily drawn by dry heat drawing instead of wet heat drawing.
  • Example 3 The same as in Example 3, except that the secondary drawing temperature was changed to 200° C., the total draw ratio was changed to 4.6 times, and the primary drawn yarn was secondarily drawn by dry heat drawing instead of wet heat drawing. to produce a monofilament.
  • Example 4 The same as in Example 3 except that the secondary drawing temperature was changed to 200° C., the total draw ratio was changed to 4.8 times, and the primary drawn yarn was secondarily drawn by dry heat drawing instead of wet heat drawing. I tried to manufacture a monofilament by using Stretching breakage occurred in the secondary stretching, and stretching could not be carried out.
  • Comparative Example 7 A monofilament was produced in the same manner as in Comparative Example 1, except that the primary draw ratio of the undrawn yarn was changed to 3.5 times.
  • the normalized scattering intensity I1 in the meridian direction and the normalized scattering intensity I2 in the equatorial direction were measured by the following measuring method, and their ratio I2/I1 was determined.
  • the ratio I2/I1 is the ratio of all the ratios I2/I1 obtained for each scattering vector q in increments of 0.000241 in the range of the scattering vector q from 0.02 nm ⁇ 1 to 0.04 nm ⁇ 1 is the average of the values.
  • the birefringence of the monofilaments was measured by the following measuring method.
  • Method for measuring birefringence The birefringence of the monofilament was obtained by measuring the retardation using a polarizing microscope equipped with a Berek compensator and using a sodium lamp as the light source.
  • Table 1 shows the manufacturing conditions and properties of the monofilaments in the above examples and comparative examples. Also, a photograph of a two-dimensional image of the monofilament of Example 1 obtained by SAXS is shown in FIG. 1, and a photograph of a two-dimensional image of the monofilament of Comparative Example 1 obtained by SAXS is shown in FIG. 1 and 2, the arrow I1 indicates the meridian direction in the SAXS two-dimensional image, and the arrow I2 indicates the equator direction in the SAXS two-dimensional image.
  • the monofilament of the example has small void scattering (scattering derived from voids) in the central equatorial direction in the SAXS two-dimensional image.
  • the I2/I1 of the monofilaments of Examples are all 5 or less, and the birefringence is 50 ⁇ 10 ⁇ 3 or more.
  • the monofilaments of Examples have improved tensile properties when knotted compared to the monofilaments of Comparative Examples.
  • the tensile strength at knotting is higher than in Example 3.
  • Comparative Examples 1 to 3 and 7 to 9 the tensile properties at the time of knotting are substantially reduced compared to the Examples. Moreover, as is clear from FIG. 2, in the monofilament of Comparative Example 1, a strong streak is observed in the central equatorial direction in the two-dimensional image of SAXS, and thus void scattering is confirmed. It is considered that this is because voids are formed inside the monofilament by performing the second drawing step at a high drawing temperature and a high drawing ratio.
  • Comparative Example 4 drawing breakage occurred in the drawing of the primary drawn yarn, and in Comparative Example 5, drawing breakage occurred in the drawing of the undrawn yarn.
  • Comparative Example 4 it is considered that the undrawn yarn was drawn without wetting, which caused voids and rupture. This is probably because in Comparative Example 5, the effect of the decrease in strength due to wetting of the undrawn yarn outweighed the effect of the improvement in strength due to the drawing of the undrawn yarn.
  • the monofilaments of the Examples have higher tensile strength due to the secondary wet heat drawing among the tensile properties developed by the dry heat drawing of the undrawn yarn.
  • a trend can be seen.
  • secondary stretching by wet heat tends to reduce the decrease in tensile elongation due to secondary stretching as compared to secondary stretching by dry heat.
  • it is expected that the balance between the tensile strength and the tensile elongation can be appropriately adjusted by adjusting the conditions of the dry heat primary drawing and the wet heat secondary drawing.
  • PA4 has relatively high hydrophilicity, it is considered that the monofilament strength is reduced in the presence of water. Therefore, it is considered that dry heat drawing is advantageous for developing strength in PA4 monofilaments. Therefore, it is considered that a polyamide having a higher hydrophobicity than PA4, such as PA6, is less susceptible to moisture absorption during stretching. Therefore, if it is an undrawn yarn of PA6, it is considered that the strength will be sufficiently improved even if it is drawn by wet heat drawing.
  • the PA4 monofilament of the present invention can be used as a synthetic fiber with excellent tensile properties, and according to the present invention, it is expected that the use of the synthetic fiber will further reduce the burden on the environment.

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JPS556726B2 (https=) * 1972-10-11 1980-02-19
JPH04136215A (ja) * 1990-09-21 1992-05-11 Kuraray Co Ltd ナイロン―４の溶融紡糸方法
WO2012157576A1 (ja) 2011-05-13 2012-11-22 独立行政法人産業技術総合研究所 ナイロン４樹脂組成物成形体及びその製造方法
JP2019137934A (ja) 2018-02-08 2019-08-22 株式会社ブリヂストン ナイロン４繊維の製造方法、ナイロン４繊維、及び、タイヤ
JP2021031790A (ja) * 2019-08-21 2021-03-01 株式会社ブリヂストン ナイロン４繊維の製造方法、及びナイロン４繊維

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EP3138698B1 (en) * 2014-06-06 2018-12-26 Bridgestone Corporation Tire
US20180305860A1 (en) * 2017-04-25 2018-10-25 Milliken & Company Pattern coated textile for active cooling
JP2023110109A (ja) 2020-06-19 2023-08-09 国立大学法人京都工芸繊維大学 ポリアミド４繊維の製造方法

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JPS556726B2 (https=) * 1972-10-11 1980-02-19
JPH04136215A (ja) * 1990-09-21 1992-05-11 Kuraray Co Ltd ナイロン―４の溶融紡糸方法
WO2012157576A1 (ja) 2011-05-13 2012-11-22 独立行政法人産業技術総合研究所 ナイロン４樹脂組成物成形体及びその製造方法
JP2019137934A (ja) 2018-02-08 2019-08-22 株式会社ブリヂストン ナイロン４繊維の製造方法、ナイロン４繊維、及び、タイヤ
JP2021031790A (ja) * 2019-08-21 2021-03-01 株式会社ブリヂストン ナイロン４繊維の製造方法、及びナイロン４繊維

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