JP2000273720A - Polyketone yarn and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a polyketone yarn having excellent yarn physical properties at a high temperature, especially modulus of elasticity and dimensional stability, suitable for an industrial material use requiring heat resistance, especially for tire cord use inexpensively in high productivity. SOLUTION: This polyketone yarn is formed from a polyketone polymer and has the minimum value of storage elastic modulus at 50-150 deg.C by a dynamic viscoelasticity measurement at 110 Hz frequency. The polyketone yarn is produced by extruding a dope composed of an aqueous solution containing at least >=50 wt.% zinc salt as a solvent from a spinneret, successively removing the solvent from the obtained fibrous material and drawing the fibrous material at least at one stage at a temperature T=150 deg.C-the melting point of the yarn under a condition of the formula σ>=2.25-0.005×T(g/d).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to fiber properties at high temperatures,
In particular, the present invention relates to a polyketone fiber excellent in elastic modulus and dimensional stability and a method for producing the fiber.

[0002]

2. Description of the Related Art Conventionally, aromatic polyketone polymers such as polyetheretherketone and polyetherketone have been known as polyketones, all of which use expensive monomers and require complicated polymerization steps. Therefore, the cost was extremely high, and it was difficult to form a large market as general-purpose fibers. On the other hand, in recent years, it has been found that by polymerizing olefins such as ethylene and propylene with carbon monoxide using palladium or nickel as a catalyst, a polyketone polymer in which carbon monoxide and olefins are copolymerized substantially completely alternately can be obtained. (Industrial Materials, December issue, page 5, 1997).

[0003] The specific chemical structure of polyketone polymers, which have been studied for fiberization, can be broadly classified into two types. One is an ethylene ketone polymer (hereinafter abbreviated as “EC polymer”) in which two monomers of ethylene and carbon monoxide are completely alternately copolymerized, and the other is propylene of about 5 to 8 mol% in addition to ethylene. A polymer in which coexisting repeating units of ethylene and carbon monoxide and repeating units of propylene and carbon monoxide are mixed (hereinafter abbreviated as “EPC polymer”) is known. EC polymer has a melting point of 26
Since it is as high as about 0 ° C. and the molecules are easily oriented sufficiently, it is known that gel spinning or wet spinning results in high-strength and high-modulus fibers. On the other hand, since this polymer is extremely easily gelled in a molten state, it is very difficult to apply melt spinning, and production of high-strength and high-modulus fibers by wet spinning has been studied.

On the other hand, the EPC polymer changes the molecule to a mobile state by introducing a propylene moiety into the EC polymer. As a result, the melting point of the polymer is lowered, and not only wet spinning but also melt spinning is possible. (JP-A-1-124617). However, this polymer has a high degree of molecular flexibility, so that it cannot exhibit a high level of mechanical properties. Low physical properties and dimensional stability, high strength,
It has been difficult to apply it to industrial materials that require high elastic modulus and high-temperature physical properties.

[0005] These polyketone fibers are expected to be used as tires that make use of high strength, high elastic modulus, adhesion to rubber, dimensional stability at high temperatures, abrasion resistance, creep resistance and chemical resistance. Applications for composite materials typified by reinforcing fibers such as cords and belts and fibers for concrete reinforcement are considered, and in view of the fiber performance required for these applications,
EC polymer fibers which can achieve high strength and high elastic modulus can be said to be the most useful fibers. However, even in the case of this EC polymer fiber, the properties of the fiber are deteriorated at high temperatures, and therefore, in applications where the fiber is subjected to high temperature treatment during processing or exposed to high temperature during use, it exhibits sufficient performance as at room temperature. Therefore, it was necessary to limit the processing temperature and use conditions, and to increase the amount of fibers used. In particular,
In the tire cord application, which is a reinforcing material for tires, it is subjected to a heat treatment of 150 ° C. or higher during processing, and in some cases, 200 ° C. or higher. Fiber properties and dimensional stability at high temperatures are very important properties.

However, according to the techniques disclosed so far, even if it is an EC polymer fiber, the fiber properties and dimensional stability at high temperatures cannot be said to be sufficient. For example, in JP-A-2-112413, JP-A-4-228613, and JP-A-4-505344, after wet-spinning with a solvent such as hexafluoroisopropanol, m-cresol, or resorcinol / water system, stretching is performed. Although methods for obtaining EC polymer fibers have been disclosed, fibers obtained by these methods have insufficient fiber physical properties and dimensional stability at high temperatures. Furthermore, while wet spinning is indispensable for industrially producing EC polymer fibers, the wet spinning techniques of polyketone polymers known hitherto have had serious drawbacks with respect to solvents.

For example, JP-A-2-112413 discloses that hexafluoroisopropanol, m-
Wet spinning of polyketone polymers using cresol and mixtures thereof is disclosed. However, hexafluoroisopropanol is extremely expensive and cannot be industrially profitable in view of the slight loss in recovery, and it is necessary to make the spinning equipment completely closed because of its high toxicity and low boiling point. Therefore, it cannot be used industrially. In addition, m-cresol can be a solvent for polyketone, but it has poor solubility and must be used in common with hexafluoroisopropanol, and it has high toxicity and strong phenol odor. There is. Further, there are drawbacks in that the mechanical properties of the fibers obtained using these solvents are low, and the spinning speed is high because the rate of desolvation from a solution using these solvents is too low. Was.

On the other hand, JP-A-4-228613, JP-A-7-508317, and JP-A-8-507
No. 328 discloses that at least one solvent is an aromatic alcohol, and specific examples thereof include resorcin / water, phenol / acetone, hydroquinone / propylene carbonate, and resorcin / propylene carbonate. ing. However, these aromatic alcohols are also highly toxic and have a strong phenolic odor, so the spinning equipment must be completely sealed. there were. In addition, the solubility of the EPC polymer in these solvents is not always sufficient, and there is a problem that the polymer concentration of the obtained dope cannot be increased, and it is difficult to obtain high strength. In addition, resorcinol /
With water, the desolvation rate in water coagulation is too slow, so methanol must be used in the coagulation bath, and spinning equipment and solvent recovery equipment must also use expensive and complicated equipment. Was. Furthermore, in the fibers obtained from the solvents disclosed in these publications, the storage elastic modulus does not have a minimum value in the dynamic viscoelasticity measurement at a frequency of 110 Hz,
There is a disadvantage that the mechanical properties and dimensional stability at high temperatures are reduced.

[0009]

SUMMARY OF THE INVENTION An object of the present invention is to provide a polyketone fiber which is excellent in fiber physical properties at high temperature, in particular, elastic modulus and dimensional stability at low cost and with good productivity.

[0010]

Means for Solving the Problems The present inventors have proposed a frequency 1
It has been found that polyketone fibers having a minimum storage elastic modulus in the range of 50 to 150 ° C. in dynamic viscoelasticity measurement at 10 Hz have excellent high-temperature elastic modulus and dimensional stability. That is, the present invention relates to a polyketone fiber formed from a polyketone polymer, wherein the storage elastic modulus has a minimum value in a range of 50 to 150 ° C. in a dynamic viscoelasticity measurement at a frequency of 110 Hz, and a polyketone fiber and a polyketone fiber thereof. It is a manufacturing method. The polymer used in the fiber of the present invention is a polyketone polymer composed of an alkylene moiety and a carbonyl group, and carbon monoxide and olefin are alternately used in that the fiber has excellent strength, adhesion, dimensional stability, and creep resistance. Copolymers obtained by copolymerization are particularly preferred. The preferred polymer is shown below by a structural formula.

[0011]

(Equation 1) That is, the preferred polymer is a polymer in which the carbonyl group in the polymer is substantially alternately bonded and arranged with the alkylene moiety derived from the olefin. In this polymer, units of carbonyl groups and units of olefins may be partially bonded, but it is preferable that 90% by weight or more is a polyketone polymer obtained by alternately copolymerizing carbon monoxide and olefin. From the viewpoint of suppressing light resistance, heat resistance, and deterioration in physical properties at high temperatures, the content of the portion where the carbon monoxide and the olefin are alternately copolymerized is preferably as large as possible, preferably 97% by weight or more, and most preferably 100% by weight. It is.

The polymer may be a copolymer of carbon monoxide and one olefin, or a copolymer of carbon monoxide and two or more olefins. Specific examples of the olefin used include ethylene, propylene, butene, propene, hexene, octene, nonene, decene, dodecene, and the like. If necessary, styrene, methyl acrylate, methyl methacrylate, vinyl acetate, undecenoic acid, undecenol, 6-
Compounds having an ethylenically unsaturated hydrocarbon such as chlorohexene, N-vinylpyrrolidone, hydroxyethyl methacrylate, and sodium allyl sulfonate may be copolymerized. Among polymers obtained from these olefins, a polymer substantially composed of only ethylene and carbon monoxide is most preferable from the viewpoint of excellent strength, elastic modulus, fiber physical properties at high temperature, and dimensional stability. In addition, from the viewpoint of increasing the solubility in a solvent during wet spinning,
A polymer obtained by copolymerizing ethylene and carbon monoxide with a compound having another olefin or an ethylenically unsaturated hydrocarbon may be used.

In addition, depending on the purpose, an antioxidant, a quenching agent, a radical scavenger, a heavy metal deactivator, a gelling inhibitor, a matting agent, an ultraviolet absorber, a pigment, etc. may be added to the polymer. Agents, other polymers, and the like. The intrinsic viscosity of the polymer used in the present invention is preferably 0.3 or more. This is because if the intrinsic viscosity is less than 0.3, the molecular weight is too low and it is difficult to form a fiber. From the viewpoint of the strength, solubility and spinnability of the obtained fiber, preferably 0.5 to 15, most preferably 2 to 10
Range. In addition, the intrinsic viscosity [η] of the polymer in the present invention is a value measured by the measuring method described in Examples of the present application.

The present inventors have drawn a polyketone fiber after performing a special spinning to obtain a fiber having a minimum storage elastic modulus in the range of 50 to 150 ° C. in a dynamic viscoelasticity measurement at a frequency of 110 Hz. It has been found that in such a case, it has excellent elastic modulus and dimensional stability especially at high temperatures. In general, it is known that the elastic modulus of a thermoplastic polymer fiber decreases with increasing temperature, and the elastic modulus decreases with increasing temperature.For polyketone polymers, the elastic modulus usually decreases with increasing temperature and reaches a minimum value. (For example, Polym. Prepr. (Am. Che.)
m. Soc. , Div. Polym. Chem. ), 3
6 , 1, 291-292, Prog. Polym. Sc
i. , Vol. 22, 8 , 1547-1605 (199
7)). On the other hand, in the case of a polyketone fiber having a storage elastic modulus having a minimum value, the elastic modulus decreases from room temperature to the minimum point temperature similarly to a normal polymer, and the temperature increases from the minimum point temperature to around 160 ° C. As the modulus increases, the elastic modulus increases. For this reason, the elastic modulus of the fiber from 150 ° C. to the melting point is more than 20% higher than that of the fiber having no minimum value. Surprisingly, the fiber having the minimum value of the storage elastic modulus has a dry heat shrinkage ratio under high heat of 20% or more lower than the fiber having no minimum value. If the temperature at which the storage elastic modulus shows a minimum is too low, the storage elastic modulus will decrease from a relatively low temperature region thereafter, and the elastic modulus at a high temperature will decrease. If the temperature showing the minimum value is too high, the elastic modulus shows a minimum near the processing temperature or the use temperature (for example, 180 ° C.). Therefore, the temperature at which the storage elastic modulus shows a minimum is preferably in the range of 50 to 150 ° C, and more preferably in the range of 80 to 130 ° C. In the present invention, the storage elastic modulus is a dynamic elastic modulus of the obtained fiber with respect to a dynamic tensile strain in the fiber axis direction (Lecture Rheology (Japanese Society of Rheology)).
p37), the value of the storage elastic modulus at a frequency of 110 Hz almost coincides with the tensile elastic modulus measured by a normal fiber tensile test. This value is measured by the measurement method described in the examples of the present application.

The higher the modulus of elasticity at high temperature, the better the workability of the material.
Since the rigidity and the dimensional stability increase, the higher the value, the better the heat resistance of the material. The modulus of elasticity of the fiber changes depending on the temperature, and the required performance varies depending on the conditions of use, etc., so it is difficult to define it with uniform numerical values, but considering the suitability for industrial material applications, especially tire cord applications When the storage elastic modulus in the dynamic viscoelasticity measurement at a frequency of 110 Hz is 180 ° C., it is preferably 80 g / d or more, and particularly preferably 120 g / d or more. On the other hand, the lower the dry heat shrinkage, the smaller the shape change and residual stress, and the better the dimensional stability. Therefore, the smaller the value, the better the heat resistance. As for the dry heat shrinkage of the fiber of the present invention, the dry heat shrinkage at 180 ° C. is preferably 4% or less, more preferably 3% or less.

These fibers are prepared by dissolving a polyketone polymer in an aqueous solution containing at least 50% by weight of a zinc salt, extruding the solution from a spinneret, and substantially removing the solvent from the fibrous material. = 150 ° C. to the melting point of the yarn and the drawing stress: σ ≧ 2.25-0.005 × T (g /
It can be obtained by giving at least one or more stretching steps under the condition of d). The zinc salt used to dissolve the polyketone polymer needs to be soluble in water. Usable zinc salts include, for example, zinc oxide, zinc chloride, zinc bromide, zinc iodide, zinc nitrate, zinc sulfate,
Zinc chlorite and the like can be mentioned. Preferably, it is a zinc salt having a solubility of 50% by weight or more in water. The zinc salt having a solubility of 50% by weight or more in water is a zinc salt that can be used to prepare a zinc salt aqueous solution having a concentration of 50% by weight or more when the zinc salt is dissolved in water. The concentration of the aqueous zinc salt solution is a value defined by the following equation.

The concentration (% by weight) of the aqueous solution of zinc salt = [weight of zinc salt / (weight of zinc salt + weight of water)] × 100 An aqueous solution of zinc salt having a solubility of 50% by weight or more in water is: It becomes possible to dissolve the polyketone polymer at a higher concentration. Examples of such zinc salts include zinc chloride, zinc bromide, zinc iodide, zinc nitrate, zinc chlorite, and the like. In terms of the solubility of the polyketone polymer, the cost of the solvent, and the stability of the aqueous solution, zinc chloride, zinc bromide,
Zinc iodide is more preferred, and zinc chloride is most preferred.

The concentration of the aqueous zinc salt solution is not particularly limited, but is preferably higher in view of the solubility of the polyketone polymer. If the concentration of the aqueous zinc salt solution is low, the concentration at which the polyketone can be dissolved and the degree of polymerization are limited, which is disadvantageous for the production cost and the fiber strength. However, if the concentration of the aqueous zinc salt solution is too high, there may be a problem that the viscosity of the aqueous solution becomes high and the dissolving operation takes a long time, and the polymer solution becomes non-uniform due to precipitation of crystals. Therefore, it is preferable that the concentration of the aqueous zinc solution is determined in consideration of the above points. The appropriate concentration varies depending on the type of the zinc salt and the temperature of the aqueous solution. For example, the preferable concentration of the aqueous zinc chloride solution is 50% by weight or more in the range of 50 to 80 ° C.
5% by weight or less.

The aqueous solution of the zinc salt may be a mixture of a plurality of the zinc salts for the purpose of improving the solubility, reducing the cost and stabilizing the dope. If necessary, an alkali metal or alkaline earth metal halide such as sodium chloride, potassium chloride or calcium chloride may be contained in an amount of 30% by weight or less. Further, other inorganic substances and organic substances may be contained at 10% by weight or less as long as the solubility is not impaired.

The concentration of the polymer in the zinc salt aqueous solution dope is preferably 0.005 to 70% by weight. The term “dope” is a term indicating a solution in which a polymer is dissolved in a solvent, and in this case, indicates a solution in which a polyketone is dissolved in the aqueous zinc salt solution. If the polymer concentration is less than 0.005% by weight, the concentration is too low, resulting in a disadvantage that the fiber is not easily formed during coagulation, and that the production cost of the fiber is too high. On the other hand, if it exceeds 70% by weight, the polymer will no longer be dissolved in the solvent. From the viewpoints of solubility, ease of spinning, and fiber production cost, the amount is preferably 0.5 to 40% by weight, and more preferably 1 to 30% by weight.

The method for producing the dope is not particularly limited.
Hereinafter, a preferred example will be described. The dope is prepared by adding the polyketone polymer to the zinc salt aqueous solution at once, or in several portions, while stirring. The form of the polyketone is not particularly limited, such as powder and chips, but powder is preferred from the viewpoint of the dissolution rate and the small amount of gel formed during the polymerization process. It is known that the synthesis of polyketone polymers can be obtained in powder form. Since this powder has a high bulk density and a rich surface with irregularities, the powder has a large specific surface area and is easily in contact with a solvent, and thus has excellent solubility. On the other hand, once melted and shaped, such as chips, the specific surface area is small and the area in contact with the solvent is small, and there is a risk of gelling during the melting process. It is recommended to use as is powder.

The temperature for dissolving is not particularly limited, but it is usually preferable to dissolve in the range of 5 to 90 ° C. from the viewpoint of dissolution rate and stability of the solvent. Further, the appropriate range is appropriately determined depending on the type of the zinc salt, the molecular weight and the concentration of the polymer. As a dissolution method, stirring using a stirring blade, stirring using a single-screw or twin-screw extruder, stirring using ultrasonic waves, or the like can be used. The polyketone solution thus obtained becomes a dope that can be filtered through a filter, if necessary, for spinning, film formation, and the like, in order to remove dust, gelled matter, undissolved polymer, catalyst residue, and the like.
If necessary, an antioxidant, a light stabilizer, a matting agent, etc. may be added to the obtained dope.

The polyketone polymer dope thus obtained can be extruded from a spinneret (spinner), and subsequently the solvent can be substantially removed from the obtained fibrous material to obtain polyketone polymer fibers. As a method of removing the solvent from the fibrous material, a method of coagulation by passing through a solvent other than the solvent used for the dope is used. It is recommended that the dope extruded from the spinneret be extruded into a solvent (coagulation bath) that is at least less soluble in the polymer than the solvent used for the dope. As the position of the spinneret, a method in which the spinneret is immersed in a coagulation bath, that is, even in the immersion method, a method in which the spinneret is placed in the air and the fibrous material exiting the spinneret enters the coagulation bath through the air phase A so-called air gap method may be used.

The solvent having at least lower solubility in the polymer than the solvent used in the dope described herein does not necessarily need to be a poor solvent for the polymer. It is only necessary that the polymer has low solubility in the polymer. Further, if necessary, the obtained fiber may be passed through a solvent having lower solubility in the polymer in multiple stages. As such a solvent having at least lower solubility in the polymer than the solvent used for the dope, the zinc salt aqueous solution or water having a lower concentration than the zinc salt aqueous solution used for the dope is most preferable. That is, as a preferred specific method, the zinc salt is gradually removed from the fibrous material while passing the fibrous material having passed through the spinneret through the bath of the aqueous zinc salt solution having a lower concentration to solidify the fibrous material. This is a method of completely coagulating by passing through. Of course, the fibrous material that has passed through the spinneret may be directly coagulated by passing it through water.

When the fibrous material is passed through a coagulation bath, it is preferable that the fibrous material be passed while being pulled at a constant speed. The winding speed is 0.001 to 1000 m / min. Depending on the spinning speed and the coagulation temperature, the zinc salt in the coagulated yarn may not be sufficiently removed in the coagulation bath. Therefore, the coagulated yarn that has exited the coagulation bath may be further washed if necessary. Any liquid may be used for washing as long as it has the ability to dissolve the zinc salt.However, in consideration of safety, solution cost, recovery cost, etc., an aqueous solution is preferable. From the viewpoint of solubility, water or an acidic aqueous solution of sulfuric acid, hydrochloric acid, phosphoric acid or the like is particularly preferable.

The thus solidified fiber containing no zinc salt can be stretched after drying or stretched while drying to obtain a stretched yarn. As a drying method, a batch drying method in which a coagulated yarn is wound once (cheese, cake or pan) in a dryer, or a coagulated yarn is continuously or directly after spinning, or After winding, a continuous drying method of drying by running on a heated roll or plate or in a heated gas may be used. The continuous drying method is preferred from the viewpoint of yarn uniformity and production cost. The drying temperature is not particularly limited.
A range from 0 ° C to 260 ° C is preferred. When drying at a temperature of 100 ° C. or higher, it is preferable to flow an inert gas around the yarn. If necessary, treatment such as relaxation and stretching may be performed while drying.

In order to finally obtain a fiber having a minimum storage elastic modulus in a range of 50 to 150 ° C. in a dynamic viscoelasticity measurement at a frequency of 110 Hz, the dried yarn must be dried at 150 ° C. to 150 ° C.
It is necessary to perform one or more drawing steps within the range of the melting point temperature of the yarn. As the heating stretching method, a conventionally known apparatus or method such as a method of running on a heated roll or plate or in a heated gas, a method of irradiating a running yarn with laser, microwave, or far-infrared ray can be employed as they are. . The stretching ratio varies depending on the spinning conditions of the coagulated yarn, drying conditions, and the like, but is preferably 3 times or more, more preferably 5 times or more,
Particularly preferably, it is desirable to perform stretching 10 times or more.

The number of stretching stages may be any, but at least one stretching stage has a stretching temperature T = 150 to 260 (° C.) and a stretching stress σ ≧ 2.25-0.005 × T (g / d )
It is important to perform stretching within the range described above. Here, the drawing temperature means the maximum temperature of the yarn at the time of drawing, and the drawing stress means the stress applied to the yarn immediately after drawing is completed (the tension at the time of drawing completion is divided by the denier of the yarn after drawing is completed). Number). If the drawing temperature is lower than 150 ° C., the drawing stress becomes too high, and troubles in the process such as fluff and yarn breakage are likely to occur, and if the drawing temperature is higher than the melting point of the yarn, the fluff and yarn due to melting of the yarn. Cutting and fusion are likely to occur. Further, the stretching stress σ is 2.25−0.005 × T
When it is lower than (g / d), the fiber structure does not sufficiently develop, the storage elastic modulus does not have a minimum value, and the fiber properties and dimensional stability at high temperatures become insufficient.

The polyketone fiber having a minimum value of 50 to 150 ° C. in the dynamic viscoelasticity measurement at a frequency of 110 Hz according to the present invention has a high elastic modulus and a high dimensional stability at a high temperature because the elastic modulus hardly decreases at a high temperature. Therefore, it is suitable for industrial materials subjected to processing and use in a high-temperature environment, particularly tire cords. In addition, the polyketone polymer dope is characterized in that the aqueous solution of zinc salt used for producing the fiber of the present invention is a solvent, while dissolving the polyketone polymer stably, and modifying the zinc salt in terms of solvent recovery. , The recovery efficiency is high, the production cost is advantageous, and the equipment is relatively simple and inexpensive. In addition, since there is no volatility, flammability or explosion in the spinning, drying and drawing equipment, wet spinning is possible with inexpensive and simple equipment without the necessity of a completely closed type or explosion-proof equipment. In addition, the fiber of the present invention has a feature that it is also efficient, and it is possible to provide the fiber of the present invention at low cost and with good productivity.

[0030]

The present invention will be described in more detail with reference to the following examples, which do not limit the scope of the present invention. The measuring method of each measured value used in the description of the embodiment is as follows. (1) Intrinsic Viscosity Intrinsic viscosity [η] is a value obtained based on the following definition formula.

(Equation 2) In the definition formula, t and T are the flow times of a dilute solution of m-cresol having a purity of 98% or more and a polyketone dissolved in m-cresol at 60 ° C. through a viscosity tube. C is the solute weight value in grams in 100 ml of the solution.

(2) Denier Measured according to JIS-L-1013. (3) Strong elongation Measured according to JIS-L-1013. (4) Dry Heat Shrinkage A value at 180 ° C. was measured according to JIS-L-1013. (5) Dynamic viscoelasticity measurement A sample obtained by tying both ends of a fiber 30 mm without slack was used as a sample, and a dynamic viscoelasticity measuring device (RheoVibron) was used.
DDV-01FP: manufactured by ORIENTEC) under the following conditions. Frequency: 110 Hz Temperature: 20 → 260 ° C. (Start measurement from 20 ° C., 2
Heating rate up to 60 ° C at a rate of 5 ° C / min) Heating rate: 5 ° C / min Measurement interval: 1 time / ° C Amplitude: 16μm Single waveform Preload: 0.1gd according to sample denier Change

(5-1) Storage Elastic Modulus The value of the storage elastic modulus (E ') at 180 ° C. was adopted. (5-2) Judgment of presence / absence of a minimum value The presence / absence of a minimum value and the minimum temperature were determined from a plot of storage elastic modulus versus temperature. Here, the minimum value means a local minimum value. For example, as shown in FIG. 1, when the storage modulus is plotted against the temperature, the plot has a downwardly convex portion, and the extension showing the lowest storage modulus among the downwardly convex portions is the minimum point. The storage elastic modulus indicated by the point is the minimum value, and the temperature indicated by the minimum point is the minimum value temperature. (6) Stretching stress The tension of the running yarn at the heater outlet was measured by a digital tension meter (DTM-0.5K: manufactured by Shinpo Kogyo KK), and the value obtained by dividing by the denier of the wound drawn yarn was used. did.

[0033]

EXAMPLE 1 A completely alternating copolymer of ethylene / carbon monoxide with an intrinsic viscosity of 4.6 was stirred at 60 ° C.
It was added to a 75% by weight aqueous zinc chloride solution. The polymer dissolves very easily, with a polymer concentration of 1
0% by weight of the dope was obtained. The resulting dope was heated to 80 ° C., filtered through a 20 μm filter, and then spun at a diameter of 0.10 mm, L / D = 1, and passed through a 50-hole spout.
After passing through an air gap of 10 mm, the mixture was extruded into water at 10 ° C. at a discharge rate of 2.5 cc / min and solidified. The coagulated yarn was subsequently washed with a 2% aqueous sulfuric acid solution and then wound at a winding speed of 5.6 m / min. 14
It was dried at 0 ° C. to obtain an undrawn yarn. The obtained undrawn yarn was drawn 6 times at 220 ° C., and subsequently drawn at 240 ° C.
Draws 2.3 times. The second stage stretching stress is 1.6.
g / d. The obtained fiber had a fineness of 72.3 d, a strength of 10.2 g / d and an elongation of 4.5%. This fiber has a minimum value of the storage elastic modulus at 95 ° C.
The storage elastic modulus at 0 ° C. is 120 g / d, and the dry heat shrinkage is 2.1.
% And very excellent performance.

[0034]

Example 2 Using the undrawn yarn of Example 1, the first stage
Stretching was performed 6 times at 80 ° C and 1.8 times at 200 ° C in the second stage. The second-stage stretching stress was 1.7 g / d. The obtained fiber had a fineness of 78.7 d, a strength of 9.8 g / d and an elongation of 3.9%. This fiber had a minimum storage modulus at 91 ° C., a storage modulus at 180 ° C. of 105 g / d, and a dry heat shrinkage of 2.9%.

[0035]

Example 3 The same polymer as in Example 1 was added to a 75% by weight aqueous zinc chloride solution with stirring at 70 ° C. to obtain a dope having a polymer concentration of 10% by weight. This dope was subjected to spinning, drying and two-stage drawing in the same manner as in Example 1. The stretching stress at the second stage of stretching was 1.6 g / d. The obtained fiber had a fineness of 70.2 d and a strength of 11.1 g.
/ D, elongation 4.3%. In addition, this fiber
Had a minimum value of storage elastic modulus, a storage elastic modulus at 180 ° C. of 123 g / d, and a dry heat shrinkage of 2.4%.

[0036]

Example 4 The same polymer as in Example 1 was added to an aqueous solution containing a mixed salt of 65% by weight of zinc chloride and 10% by weight of sodium chloride while stirring at 70 ° C. to give a polymer concentration of 13% by weight. Was obtained. This dope was spun and dried in the same manner as in Example 1. The obtained unstretched yarn was stretched 7 times at 220 ° C. and then 2.2 times at 240 ° C. The second-stage stretching stress was 1.7 g / d, and the obtained fiber had a fineness of 85.0 d and a strength of 12.1 g / d.
d, elongation was 4.9%. This fiber also has a minimum storage modulus at 96 ° C and a modulus at 180 ° C of 125.
g / d, the dry heat shrinkage was 2.5%.

[0037]

Example 5 250% of the drawn yarn obtained in Example 4 was further added.
The film was stretched 1.4 times at ℃. Stretching stress is 1.7 g / d
And the resulting fiber had a fineness of 64.2 d and a strength of 14.8.
g / d and elongation 3.9%. This fiber also has 11
It had a minimum value of the storage elastic modulus at 2 ° C., an elastic modulus at 180 ° C. of 145 g / d, and a dry heat shrinkage of 1.9%, which were excellent performances.

Comparative Example 1 The undrawn yarn obtained in Example 1 was drawn 6 times at 220 ° C. The stretching stress at this time is 0.7 g / d
Met. This drawn yarn has a fineness of 157.1d and a strength of 5.
It was 6 g / d, elongation 5.8%, and there was no minimum value in the storage modulus. The storage modulus at 180 ° C was 32 g / d, and the dry heat shrinkage was 5.0%, which was insufficient.

[0038]

Comparative Example 2 The drawn yarn obtained in Comparative Example 1 was continuously
When the second stretching was performed at 40 ° C., the yarn was broken at 1.6 times. At this time, the drawing stress was 2.1 g / d, but the drawn yarn did not show a minimum value of the storage elastic modulus.
The storage elastic modulus at 80 ° C. is 47 g / d, and the dry heat shrinkage is 5.2.
% Was insufficient.

Comparative Example 3 The undrawn yarn obtained in Example 1 was drawn 6 times at 220 ° C. The melting point of this yarn was 267 ° C. Subsequently, when this yarn was stretched in the second stage at 270 ° C., the yarn was melt-cut and could not be stretched.

[0039]

Comparative Example 4 The same polymer as in Example 1 was dissolved at 80 ° C. in an aqueous solution containing 75% by weight of resorcin to obtain a dope having a polymer concentration of 10% by weight. The obtained dope was discharged at a discharge rate of 2.5 cc / min using the same spinner as in Example 1, and extruded through a 10 mm air gap into a -5 ° C. methanol bath to obtain a coagulated yarn. Was. The obtained coagulated yarn was washed with methanol and dried at 140 ° C. to obtain an undrawn yarn. This undrawn yarn was drawn four times at 220 ° C. The stretching stress was 0.4 g / d. Continue 2
The film was stretched 3.2 times at 40 ° C. The stretching stress is 1.6 g
/ D. The obtained drawn yarn had a fineness of 75.3 d, a strength of 10.5 g / d, and an elongation of 3.6%. This fiber is
The storage elastic modulus had no minimum value, the storage elastic modulus at 180 ° C was 79 g / d, and the dry heat shrinkage was insufficient at 4.5%.

[0040]

The present invention provides a polyketone fiber having excellent fiber properties and dimensional stability at high temperatures, and a method for producing the same. Polyketone fibers with excellent high-temperature elastic modulus and dimensional stability that could not be obtained with conventional technology can be obtained, and industrial materials applications that require high-temperature processing and use at high temperatures, especially in the field of tire cords Application is expected. In addition, the aqueous zinc salt solution used as a solvent in the process of producing the fiber of the present invention has high solubility in polyketone polymers, and at the same time, is excellent as an industrial compound having low toxicity, easy recovery, and non-volatility. Has the characteristics
It is possible to produce at low cost and with high productivity, which cannot be realized with conventional solvents.

[Brief description of the drawings]

FIG. 1 is a diagram plotting storage elastic modulus with respect to temperature.

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Claims (9)

[Claims] 1. A polyketone fiber formed from a polyketone polymer, wherein the storage elastic modulus has a minimum value in a range of 50 to 150 ° C. in a dynamic viscoelasticity measurement at a frequency of 110 Hz. fiber. 2. A dynamic viscoelasticity measurement at a frequency of 110 Hz, wherein a storage elastic modulus at 180 ° C. is 80 g / d or more, and a dry heat shrinkage at 180 ° C. is 4% or less. Polyketone fiber. 3. The polyketone fiber according to claim 1, wherein the polyketone polymer is a polymer obtained by copolymerizing carbon monoxide and an olefin. 4. The polyketone fiber according to claim 3, wherein 90% by weight or more of the polyketone polymer is a polymer obtained by alternately copolymerizing carbon monoxide and an olefin. 5. The polyketone polymer has an intrinsic viscosity of 0.3.
The polyketone fiber according to claim 1, wherein: 6. The polyketone fiber has at least 50 wt.
% Of a zinc salt is extruded from a spinneret, and after removing the solvent from the obtained fibrous material, when the stretching temperature is T and the stretching stress is σ, T = 150 ° C. to the melting point of the yarn, and σ ≧ 2.25
The method for producing a polyketone fiber according to any one of claims 1 to 5, wherein drawing is performed at least one step or more under the condition of -0.005 x T (g / d). 7. The method for producing a polyketone fiber according to claim 6, wherein the polymer concentration in the zinc salt aqueous solution dope is 0.005 to 70% by weight. 8. The method for producing a polyketone fiber according to claim 6, wherein the zinc salt is zinc chloride. 9. The method for producing a polyketone fiber according to claim 6, wherein the dope comprises a zinc salt and a complex salt with a metal salt other than zinc.