JP2000034620A - Polymer dope and method for producing fiber using the same, and fiber produced by the same method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prepare an aliphatic polyketone polymer dope at a low cost, which is in a state that an aliphatic polyketone is highly dissolved, is excellent in moldability and solvent-recovery and is useful for producing fibers, etc., by adopting nitric acid as a solvent. SOLUTION: When preparing a dope of an aliphatic polyketone polymer obtained by copolymerizing carbon monoxide with an olefin and having >=0.3 specific viscosity, the method of this invention is to adopt nitric acid (pref. having >=10 wt.% concentration) as a solvent. It is pref. that the weight content of the polymer in the dope is 0.00570% and the dope is extruded from a spinneret, followed by removing the solvent from the fibrous materials and by drawing them at 0300 deg.C to form aliphatic polyketone fibers.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an aliphatic polyketone polymer dope, a method for producing a fiber using the dope, and a fiber obtained by the method.

[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 for fibers. In contrast, in recent years, carbon monoxide and ethylene, by polymerizing olefins such as propylene using a palladium or nickel catalyst,
It has been found that an aliphatic polyketone polymer in which carbon monoxide and the olefin are substantially completely copolymerized alternately can be obtained (Industrial Materials, December, p. 5, p. 199).
7 years).

The specific chemical structure of an aliphatic polyketone polymer, which has been studied for fiberization, is as follows:
It can be roughly divided into two types. One is ethylene and carbon monoxide.
Is an ethylene ketone polymer (hereinafter abbreviated as “EC polymer”) in which two monomers are completely alternately copolymerized, and the other is a copolymer in which about 5 to 8 mol% of propylene is present in addition to ethylene. A polymer (hereinafter abbreviated as “EPC polymer”) in which completely alternating copolymerized units of carbon oxide and completely alternating copolymerized units of propylene and carbon monoxide are mixed is known.

Since the melting point of the EC polymer is as high as about 260 ° C. and the molecules are easily oriented, it is known that high strength and high modulus fibers can be obtained by gel spinning or wet spinning. On the other hand, since this polymer is extremely liable to gel in a molten state, it is difficult to apply melt spinning. Therefore, production of high-strength and high-modulus fibers by wet spinning has been studied. In contrast, EPC
By introducing a propylene moiety into the EC polymer, the polymer is changed into a state in which the molecule can easily move. As a result, the melting point of the polymer is lowered, and not only wet spinning but also melt spinning can be performed (Japanese Patent Laid-Open No. 1-124617). reference). However, since this polymer has high molecular flexibility, a high level of mechanical properties cannot be exhibited.

The expected uses of aliphatic polyketone polymer fibers include high strength, high elastic modulus, adhesion to rubber,
Applications for composite materials typified by tire cords, belts and other reinforcing fibers, and concrete reinforcing fibers that make use of dimensional stability at high temperatures, abrasion resistance, creep resistance, and chemical resistance are being considered. Considering the fiber performance required for the application, EC polymer fibers that can exhibit high strength and high elastic modulus can be said to be the most useful fibers. Therefore, in order to obtain this fiber industrially, it is very important to establish a wet spinning technique for an aliphatic polyketone polymer on the premise of an EC polymer. Wet spinning techniques all have significant disadvantages with respect to solvents.

For example, Japanese Patent Application Laid-Open No. Hei 2-112413 discloses a wet spinning method of an aliphatic polyketone polymer, wherein hexafluoroisopropanol is used as a solvent,
The use of m-cresol and mixtures thereof is disclosed. However, hexafluoroisopropanol is extremely expensive and cannot be industrially profitable at all, even if a slight loss in recovery is taken into consideration. In addition, it is highly toxic, and it is necessary to make the spinning equipment completely closed. It cannot be used for the purpose. In addition, m-cresol can be used as a solvent for aliphatic polyketone polymers, but it has poor solubility and must be used in common with hexafluoroisopropanol. Need to be Furthermore, the drawbacks are that the mechanical properties of the fibers obtained using these solvents are low, and the rate of desolvation from the solution using these solvents is too low, and if the spinning speed is increased, fiberization becomes difficult. There was also.

On the other hand, JP-A-4-228613, JP-A-7-508317, and JP-A-8-507
No. 328 discloses that a solvent that is at least one kind of aromatic alcohol is used, and specific examples thereof include resorcin / water, phenol / acetone, hydroquinone / propylene carbonate, and resorcin / propylene carbonate. I have. However, these aromatic alcohols are also highly toxic and have a strong phenol odor, so it is necessary to make the spinning equipment completely closed.
Further, when a flammable organic solvent is used as a cosolvent, there is a problem that explosion-proof equipment is required. 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 /
Since the desolvation rate in water coagulation is too slow with water solvent,
Methanol must be used in the coagulation bath, and expensive and complicated explosion-proof equipment must be used.

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to enable wet spinning with a simple spinning facility using a solvent which has a high solubility of an aliphatic polyketone polymer, is inexpensive and has excellent recoverability. An object of the present invention is to provide an aliphatic polyketone polymer dope, a method for producing a fiber using the dope, and a fiber obtained by the method.

[0009]

Means for Solving the Problems In order to solve the above problems, the present inventors have conducted a detailed search for a solvent for an aliphatic polyketone polymer, and as a result, nitric acid has become a very good solvent for an aliphatic polyketone polymer. The present inventors have found out that the present invention has been achieved as a result of further studies. That is, the present invention relates to an aliphatic polyketone polymer dope, in which the solvent is nitric acid in the aliphatic polyketone polymer dope, a method for producing a fiber using the dope, and a fiber obtained by the method.

The polymer used in the dope of the present invention is an aliphatic polyketone polymer composed of an alkylene moiety and a ketone group, and is excellent in strength, adhesiveness, dimensional stability and creep resistance as fibers. A copolymer obtained by alternately copolymerizing carbon and olefin is particularly preferred. The preferred polymer structure is shown below.

[0011]

Embedded image Here, R represents an alkylene moiety.

That is, the preferred polymer is a polymer in which ketone groups in the polymer are substantially alternately arranged with alkylene moieties derived from olefin. In this polymer, units of ketone groups and units of olefins may be partially connected, but it is preferred that 90% by weight or more is an aliphatic polyketone polymer obtained by alternately copolymerizing carbon monoxide and olefin. . From the viewpoint of reduction in light resistance and heat resistance, the content of the portion where carbon monoxide and olefin are alternately copolymerized is preferably as high as possible, more preferably 97% by weight or more, and most preferably 100% by weight.

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, styrene, methyl acrylate,
Examples include methyl methacrylate, vinyl acetate, undecenoic acid, undecenol, 6-chlorohexene, N-vinylpyrrolidone and the like. As the polymer obtained from these olefins, a polymer composed substantially of only ethylene and carbon monoxide is most preferable from the viewpoint that a high strength and a high elastic modulus can be achieved. Further, from the viewpoint that the solubility in the solvent of the present invention is high and the productivity is excellent, the olefin constituting the aliphatic polyketone polymer is 3 to
A copolymer containing 10 mol%, preferably 4 to 8 mol%, of propylene and containing alternating copolymer units of carbon monoxide and ethylene and alternating copolymer units of carbon monoxide and propylene is preferred.

The polymer may contain additives such as an antioxidant, a gelling inhibitor, other polymers, a matting agent, and an ultraviolet absorber, depending on the purpose. 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. It is preferably in the range of 0.5 to 15, and most preferably 2 to 10, in consideration of the strength, solubility and spinnability of the obtained fiber.

The solvent used in the present invention must be nitric acid. In this case, the concentration of the nitric acid is preferably 10% by weight or more. Although nitric acid dissolves the aliphatic polyketone polymer surprisingly well, this is a very characteristic phenomenon only for nitric acid. That is, instead of nitric acid, other protonic acids such as formic acid and acetic acid cannot be used as a solvent because their solubility is extremely low. He also stated that nitric acid was inexpensive compared to conventionally known solvents, that it could be easily recovered by distillation, and that flammability and explosion could be achieved with relatively simple spinning equipment and wet spinning was possible. It also has features.

Here, nitric acid is a solvent composed of HNO ₃ and water, and the concentration indicates the weight fraction of HNO ₃ in nitric acid.
If the concentration is less than 10% by weight, the solubility becomes too low, and the polymer cannot be sufficiently dissolved. Preferably,
40-8 from the viewpoint of solubility and deterioration of the polymer by nitric acid
0% by weight is preferred, and 50 to 70% by weight is particularly preferred.
It is. Further, other solvents such as an organic solvent and an inorganic solvent may be contained in an amount of 10% by weight or less as long as the solubility of nitric acid is not impaired.

The polymer concentration in the dope of the present invention is preferably 0.005 to 70% by weight. The dope is a word indicating a solution obtained by dissolving a polymer in a solvent, and in this case, a solution obtained by dissolving an aliphatic polyketone polymer in nitric acid. Polymer concentration of 0.0
If it is less than 05% by weight, the concentration is too low, and it has a disadvantage that it is difficult to become a fiber at the time of coagulation. 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, preferably 0.5 to 40% by weight, more preferably 1 to 30% by weight.
It is. The method for producing the dope of the present invention is not particularly limited, but will be described below with reference to preferred examples.

The dope of the present invention is produced by adding an aliphatic polyketone polymer to nitric acid having a concentration of 10% by weight or more while stirring at once or in several portions and dissolving it. The form of the aliphatic polyketone polymer is not particularly limited, such as powder, chips, etc., but powder is preferred from the viewpoint of the dissolution rate in nitric acid and the amount of gel formed during the polymerization process is small. It is known that the synthesis of aliphatic 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, chips that are once melted and shaped, such as chips, have a small specific surface area and a small area that comes into contact with the solvent, and gelation may occur during the melting process. It is recommended to use the polymer as it is in powder form. In addition, nitric acid has the ability to oxidize and nitrate aliphatic polyketone polymers, albeit very little, but not to an industrial degree. In order to reduce this ability as much as possible, it is preferable to use a stabilizer such as urea or a derivative thereof as necessary.

The temperature for dissolving is not particularly limited,
From the viewpoint of suppressing the decomposition of the polymer, it is usually 50C or lower, preferably room temperature or lower, and more preferably 5 to -10C.
Range. It is particularly preferable to dissolve the polymer at 5 ° C. or lower from the viewpoint of suppressing the decomposition and yellowing of the polymer. The dissolution time is not particularly limited, but it is not preferable that the dissolution usually takes 36 hours or more because the polymer is denatured. Preferably, it is about 1 second to 24 hours. In order to achieve the dissolution in such a short time, it is preferable to perform efficient stirring. As such a dissolving method, stirring using a stirring blade, stirring using a single or twin screw extruder, ultra Agitation using sound waves or the like is used. In this case, it is extremely important to prevent the temperature of the mechanical part coming into contact with the solvent or the solution from becoming higher than the solution temperature due to the heat of stirring, in order to suppress the denaturation of the dope. Is preferably cooled from the inside of the machine using a refrigerant or the like.

The thus obtained aliphatic polyketone polymer dope is a dope which can be subjected to spinning, film formation, etc. through a filter in order to remove dust, gelled matter, undissolved polymer, catalyst residue and the like, if necessary. . If necessary, an antioxidant, a light stabilizer, a matting agent, etc. may be added to the obtained dope. The aliphatic polyketone polymer dope thus obtained is extruded from a spinneret, and subsequently, the solvent is substantially removed from the resulting fibrous material to obtain aliphatic polyketone polymer fibers. The method of removing the solvent from the fibrous material may be any of a method of coagulation by passing through a solvent other than the solvent used for the dope and a method of dry coagulation by heating, but the former method is preferred from the viewpoint of suppressing the decomposition of the polymer. Is preferred.

As a method for coagulation by passing through a solvent other than the solvent used for the dope, the dope extruded from the spinneret is a solvent (coagulation bath) having at least a lower solubility for the polymer than the solvent used for the dope. It is recommended to extrude. Regarding the position of the spinneret, even in the method of immersing the spinneret in the coagulation bath, that is, the dipping method, the spinneret is arranged in the air, and the fibrous material coming out of the spinneret passes through the air phase and enters the coagulation bath. 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. The solubility should be low. 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, nitric acid or water having a lower concentration than the nitric acid used for the dope is most preferable. That is, as a preferred specific method, nitric acid falls off from the fibrous material while the fibrous material passed through the spinneret passes through the lower-concentration nitric acid bath, and if necessary, passes through a lower-concentration nitric acid bath, Further, if necessary, neutralization is carried out through a dilute aqueous alkali solution such as sodium hydroxide, potassium hydroxide, calcium hydroxide, sodium carbonate, potassium carbonate, etc., and finally the solution is completely coagulated by passing through water. Of course, the fibrous material that has passed through the spinneret may be coagulated by passing it directly 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 in the range of 0.001 to 1000 m / min.
The fiber substantially free of nitric acid thus coagulated is once wound or dried without being wound,
Alternatively, a drawn yarn can be obtained by stretching 1.1 times or more, preferably 3 times or more, more preferably 4 times or more while drying or before drying. Stretching is preferably performed at 0 to 300 ° C, preferably 5 to 200 ° C.

[0024]

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.

[Η] = lim (T−t) / (t · C) C → 0 In the formula, t and T are m-cresol having a purity of 98% or more, and an aliphatic polyketone polymer dissolved in m-cresol. Of the diluted solution at 60 ° C. in a viscosity tube. C is the solute weight value in gram units in 100 ml of the above solution. (2) High elongation The high elongation of the yarn is JIS-L-
It measured according to 1013.

[0026]

Example 1 Intrinsic viscosity 0.5 represented by the following structural formula
While stirring at −2 ° C. a completely alternating terpolymer of olefin and carbon monoxide consisting of ethylene / propylene / carbon monoxide copolymerized with 6 mol% of propylene,
Of nitric acid. The polymer dissolved very easily, and a dope having a polymer concentration of 30% by weight was obtained within a dissolution time of 30 minutes. The resulting dope was slightly yellow. The obtained dope was immediately dropped into a large amount of water, and a fibril-like polymer was recovered. The recovered polymer was thoroughly washed with water to completely remove nitric acid and dried. Although the recovered polymer was slightly yellowed, the infrared absorption spectrum and NMR spectrum of the polymer were measured, and there was no change with respect to the raw material polymer. This indicates that the raw material polymer was completely dissolved without being decomposed into nitric acid.

[0027]

Embedded image

[0028]

Example 2 A fully alternating ethylene / carbon monoxide copolymer having an intrinsic viscosity of 1.0, represented by the following structural formula, was added to 67% by weight nitric acid with stirring at -2 ° C. The polymer dissolved very easily, and a dope having a polymer concentration of 15% by weight was obtained within a dissolution time of 30 minutes. The resulting dope was slightly yellow. The obtained dope was immediately dropped into a large amount of water, and a fibril-like polymer was recovered. The recovered polymer was thoroughly washed with water to completely remove nitric acid and dried. Although the recovered polymer was slightly yellowed, the infrared absorption spectrum and the NMR spectrum of the polymer were measured, and there was no change with respect to the raw material polymer. This indicates that the raw material polymer was completely dissolved without being decomposed into nitric acid.

[0029]

Embedded image

[0030]

Example 3 The dope obtained in Example 2 was passed through a 20 μm filter, and then passed through a plunger-type extruder having a spinning diameter of 1.5 mm, and sequentially placed in a bath of 9% by weight nitric acid and water for 1 m.
/ Min, and the obtained undrawn yarn was drawn in an oven at 250 ° C at a draw ratio of 7 times. The obtained fiber had a strength of 7 g / d and an elongation of 25%.

[0031]

The present invention provides a nitric acid dope of an aliphatic polyketone polymer, a method for producing a fiber using the dope, and a fiber obtained by the method. The nitric acid used as the solvent dissolves the aliphatic polyketone polymer surprisingly well, and at the same time, the obtained dope is extremely excellent in formability as a forming dope such as fiberization and film formation.

Claims (10)

[Claims] 1. A dope of an aliphatic polyketone polymer, wherein the solvent is nitric acid. 2. The aliphatic polyketone polymer dope according to claim 1, wherein the aliphatic polyketone polymer is a polymer obtained by copolymerizing carbon monoxide and an olefin. 3. 90% by weight of the aliphatic polyketone polymer
3. The aliphatic polyketone polymer dope according to claim 2, wherein the above is a polymer obtained by alternately copolymerizing carbon monoxide and an olefin. 4. The aliphatic polyketone polymer dope according to claim 1, wherein the intrinsic viscosity of the aliphatic polyketone polymer is 0.3 or more. 5. A polymer having a concentration of 0.005 to 70% by weight.
The aliphatic polyketone polymer dope according to any one of claims 1 to 4, wherein 6. The aliphatic polyketone polymer dope according to claim 1, wherein the solvent is 10% by weight or more of nitric acid. 7. A method for producing fibers by extruding an aliphatic polyketone polymer dope from a spinneret and subsequently substantially removing a solvent from the obtained fibrous material. A method for producing a fiber, comprising using the aliphatic polyketone polymer dope described above. 8. The method for producing a fiber according to claim 7, wherein the fiber from which the solvent has been substantially removed is drawn. 9. The method according to claim 8, wherein the stretching is performed at a temperature in the range of 0 to 300 ° C. 10. An aliphatic polyketone polymer fiber obtained by the method for producing a fiber according to claim 7.