JP4565695B2 - Method for producing polyketone solution - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for producing a polyketone solution used for producing molded articles such as fibers and films of polyketone.
[0002]
[Prior art]
By polymerizing carbon monoxide and an olefin such as ethylene or propylene using a transition metal complex such as palladium or nickel as a catalyst, a polyketone in which carbon monoxide and the olefin are substantially completely alternately copolymerized can be obtained. Is known (Industrial Materials, December issue, page 5, 1997). Many researchers have studied the application of polyketone as a fiber for industrial materials, taking advantage of its high strength, high elastic modulus, heat resistance, dimensional stability at high temperatures, adhesion, and creep resistance properties such as tire cords and belts. Application to composite materials such as reinforcing fibers and concrete reinforcing fibers is expected.
[0003]
In particular, polyketone composed of ethylene and carbon monoxide (hereinafter abbreviated as “ECO”) has high crystallinity and melting point, so it is most easy to obtain high-strength and high-modulus fibers and films. It is also most excellent in thermal stability such as low shrinkage. As a method for producing this ECO fiber, since melt spinning is difficult, ECO is dissolved in a solvent and fiberized by a dry or wet spinning method. For example, the solvents described in JP-A-2-112413, JP-A-4-228613, JP-A-4-505344, etc., for example, hexafluoroisopropanol, m-cresol, chlorophenol, resorcin / water, phenol / Acetone, propylene carbonate / hydroquinone, pyrrole, resorcin / propylene carbonate, pyridine, formic acid and other organic solvents can be used, but these solvents are expensive, highly toxic or flammable. It is necessary to use a high coagulant, and there are problems in industrial use.
[0004]
On the other hand, for example, International Patent Application No. 99/18143, Japanese Patent Application No. 11-72091, Japanese Patent Application No. 11-167370, etc. include aqueous solutions of zinc salts, calcium salts, iron salts, and the like. Can be used as a solvent. These are low toxicity, nonflammable, inexpensive, excellent in spinning stability and solvent recoverability, and are advantageous as industrial solvents.
However, the method for producing a polyketone solution using a solvent in the latter patent document includes a method in which powdery polyketone is added to the solvent and dissolved by stirring, and a method in which the polyketone solution is dissolved under reduced pressure so that bubbles do not enter. It is only disclosed, and there is no disclosure regarding a technique that dissolves uniformly and at high speed.
[0005]
[Problems to be solved by the invention]
For example, polyketone powder is added to an aqueous solution such as zinc salt, calcium salt, iron salt or the like found in International Patent Application No. 99/18143, Japanese Patent Application No. 11-72091, Japanese Patent Application No. 11-167370, etc. In the case of producing a polyketone solution by dissolving, it has been found that it is easy to form a hardly soluble polyketone aggregate during dissolution by the conventional method. This is considered to be because the polyketone powder is mixed with the aqueous salt solution having a salt concentration of 60% by weight or more. In the salt aqueous solution having a salt concentration of 60% by weight or more, since the dissolution rate of the polymer is high, only the surface of the polyketone powder dissolves to form a film, thereby preventing the salt aqueous solution from penetrating into the polyketone powder.
[0006]
Further, when such polyketone powder comes into contact, large polyketone aggregates (so-called “mamakoko”) are formed, and the aqueous salt solution is less likely to penetrate inside. Once the polyketone agglomerates are formed, it takes time to produce a uniform solution, which leads to polymer modification and molecular weight reduction, which causes problems. In particular, this problem becomes significant when a polyketone solution is produced using a high molecular weight polyketone or when a high-concentration polyketone solution is produced. In the production of polyketone fibers used in the field of industrial materials such as tire cords that require high strength and high elastic modulus, a spinning solution of high molecular weight polyketone is often used, and the solution of this problem is important.
That is, the problem to be solved by the present invention is to provide a method for producing a uniform polyketone solution at a high speed by suppressing the generation of polyketone aggregates when the polyketone is mixed with the above solvent.
[0007]
[Means for Solving the Problems]
In order to solve the above problems, the present inventors have studied in detail a method for producing a polyketone solution. As a result, zinc salts, calcium salts, thiocyanates, irons having a salt concentration of 0.01 wt% or more and 59 wt% or less. After the polyketone is dispersed in an aqueous solution containing at least one salt selected from salts, a suspension is prepared, and then water is added from the suspension until the salt concentration is 60 wt% or more and 90 wt% or less. By adopting the separation and removal method, the solvent uniformly penetrates into the interior of the polyketone powder, so that the occurrence of polyketone aggregates is suppressed, and it becomes possible to produce a uniform polyketone solution at high speed. The present invention has been reached.
[0008]
That is, the present invention contains at least one salt selected from zinc salts, calcium salts, thiocyanates, and iron salts in which the polyketone represented by the following structural formula (1) is 95 mol% or more of the repeating units. in the method for manufacturing a polyketone solution prepared by dissolving in an aqueous solution, the salt concentration is 0.01 wt% or more 59 wt% or less of the salt solution, the longest portion less dispersed powdery said polyketone 5mm or 0.01mm After the polyketone suspension is prepared, water is separated and removed from the suspension until the salt concentration reaches 60% by weight or more and 90% by weight or less. .
[0009]
[Chemical 2]
The polyketone used in the present invention is a polyketone in which 95 mol% or more of the repeating units is represented by the above formula (1). A repeating unit other than the above formula (1), for example, one shown in the following formula (2) may be contained within a range of less than 5 mol%.
[0010]
[Chemical 3]
Here, in the formula, R is 1 to 30 organic groups other than ethylene, and examples thereof include propylene, butylene, 1-phenylethylene and the like. Some or all of these hydrogen atoms may be substituted with a halogen group, an ester group, an amide group, a hydroxyl group, or an ether group. Of course, R may be two or more, for example, propylene and 1-phenylethylene may be mixed. It is preferable that 97 mol% or more of the repeating unit is a polyketone represented by the above formula (1) from the viewpoints that high strength and high elastic modulus can be achieved, and strength and elasticity retention at high temperatures are excellent. Most preferably, it is 100 mol%.
[0011]
These polyketones may contain additives such as antioxidants, radical inhibitors, other polymers, matting agents, ultraviolet absorbers, flame retardants, and metal soaps as necessary.
The intrinsic viscosity [η] of the polyketone used in the present invention is not particularly limited, but is preferably 2 dl / g or more in that a high-strength polyketone fiber can be obtained. However, when [η] is too large, the solubility and spinnability tend to deteriorate, and therefore, it is preferably 20 dl / g or less. A more preferable range of [η] is 3 to 15 dl / g, particularly preferably 4 to 10 dl / g.
[0012]
The salt used in the present invention needs to be at least one salt selected from zinc salt, calcium salt, thiocyanate, and iron salt. Specific examples of zinc salts include zinc chloride, zinc bromide, zinc iodide, zinc nitrate, zinc sulfate, zinc chlorite, and zinc thiocyanate. Examples of calcium salts include calcium bromide and calcium iodide. And thiocyanate include zinc thiocyanate, aluminum thiocyanate, ammonium thiocyanate, calcium thiocyanate, potassium thiocyanate, magnesium thiocyanate, sodium thiocyanate, barium thiocyanate, and the like. Examples of iron salts include iron bromide, iron iodide, and iron chloride. Of these salts, zinc halide, calcium bromide such as zinc chloride, zinc bromide and zinc iodide are preferred in terms of solubility of polyketone, cost of solvent and stability of aqueous solution, most preferably zinc chloride. is there. In addition, for the purpose of improving solubility, reducing costs, and stability of the polyketone solution, a plurality of the above salts may be mixed. Moreover, you may mix in the range which the metal salt melt | dissolved in water other than said salt does not inhibit the objective of this invention.
[0013]
Furthermore, when using a zinc halide, mixing an alkali metal halide salt or an alkaline earth metal halide salt reduces the coloration of the polymer when dissolved at high temperatures, or increases the coagulation rate in the spinning process, This is preferable in that the spinning speed can be increased. Examples of alkali metal halide salts and alkaline earth metal halide salts include sodium chloride, calcium chloride, lithium chloride, barium chloride, sodium bromide, calcium bromide, lithium bromide, barium bromide, sodium iodide, and iodide. Calcium, lithium iodide, barium iodide and the like can be mentioned, and sodium chloride and calcium chloride are particularly preferable. The weight ratio of zinc halide to alkali metal halide salt or alkaline earth metal salt is preferably 95/5 to 20/80 from the viewpoint of improving stability during dissolution or improving spinnability. More preferably, it is 90 / 10-30 / 70, Most preferably, it is 80 / 20-40 / 60.
[0014]
The water used for the aqueous solution of these salts is not particularly limited as long as it can be used industrially, and any water such as drinking water, river water, and ion exchange treated water can be used. Furthermore, an organic solvent such as methanol, ethanol, ethylene glycol, acetone, dimethyl sulfoxide, N-methylpyrrolidone is contained within a range that does not hinder the ability of the aqueous salt solution to dissolve the polyketone, usually within 30% by weight of water. Also good.
[0015]
The suspension of the present invention is prepared by dispersing the polyketone in an aqueous salt solution having a salt concentration of 0.01% by weight to 59% by weight. In addition, the salt concentration here is a value defined by the following formula.
Salt concentration (% by weight) = [weight of salt / (weight of salt + weight of water)] × 100
The suspension means a state in which polyketone particles are not completely dissolved in the aqueous salt solution but are solid-liquid dispersed. When the salt concentration is higher than 59% by weight, polyketone particles aggregate when the polyketone is mixed and stirred in the aqueous salt solution, and a suspension cannot be formed. On the other hand, if the salt concentration is less than 0.01% by weight, it takes time to separate and remove water from the suspension, and the dissolution rate becomes slow. A preferred range is 1 to 50% by weight, and a more preferred range is 10 to 40% by weight.
[0016]
The shape of the polyketone is preferably a powder from the viewpoint that a uniform suspension can be easily obtained. The size of the powder is preferably such that the longest part is 0.01 mm or more and 5 mm or less in terms of dispersibility and permeability of the aqueous salt solution. In addition, the polymer ratio of the polyketone in the suspension varies depending on the salt concentration of the aqueous salt solution and the salt concentration and polymer concentration of the polyketone solution to be produced, but if the polymer ratio is large, the fluidity of the suspension decreases. 20% by weight or less is preferable from the viewpoint that the operation of removing water from the suspension becomes difficult. The polymer ratio of the suspension is a value calculated by the following formula.
Suspension polymer ratio (wt%)
= [Weight of polymer / (weight of polymer + weight of aqueous salt solution)] × 100
[0017]
It is possible to produce a polyketone solution by separating and removing water from the suspension thus obtained until the salt concentration reaches 60% by weight or more. When the salt concentration is less than 60% by weight, the dissolution is non-uniform, and when it is higher than 90% by weight, the salt becomes non-uniform due to precipitation of the salt, resulting in an unsuitable polyketone solution for long-term stable spinning. End up. From the viewpoint that a polyketone solution having a higher molecular weight and / or a higher polymer concentration can be produced, the preferred salt concentration range is 61 to 85% by weight. The preferred polymer concentration range of the polyketone solution produced as described above is 1 to 40% by weight. If it is less than 1% by weight, it is difficult to increase the spinning speed due to poor coagulability, and if it is higher than 40% by weight, the spinnability becomes poor. Furthermore, it is preferably 3 to 30% by weight, and most preferably 5 to 20% by weight. In addition, the polymer concentration here is a value calculated by the following formula.
Polymer concentration (wt%)
= [Weight of polymer / (weight of polymer + weight of aqueous salt solution)] × 100
[0018]
There is no particular limitation on the method for separating and removing water, a method for evaporating water by heating, a method for evaporating water by reducing pressure, a method for separating water using a reverse osmosis membrane, or a method combining these, etc. Is mentioned. However, since the polyketone in the aqueous salt solution may denature or lower the molecular weight at high temperatures, a method capable of separating and removing water at as low a temperature as possible is preferable. From such a viewpoint, a method of evaporating water under reduced pressure or a method of separating water using a reverse osmosis membrane is preferable, and it is most preferable to evaporate water under reduced pressure from the viewpoint of concentration speed and simplicity of the apparatus. The decompression condition is preferably 0.1 to 750 torr, more preferably 1 to 200 torr, from the viewpoint of apparatus cost and water evaporation efficiency. The temperature condition is preferably high in view of water evaporation efficiency, and is preferably low in consideration of polyketone modification and molecular weight reduction. As a preferable temperature range, it is 0-200 degreeC, Furthermore, 30-150 degreeC is preferable and 60-120 degreeC is especially preferable. Further, it is preferable to spread the suspension in a film form in that the evaporation rate of water is increased and the efficiency of separating water from the suspension is further improved.
[0019]
In addition, when separating and removing water from the suspension, it is preferable to stir the suspension from the viewpoint of improving dissolution efficiency, and either a batch type or continuous type stirrer can be used. As a batch type stirrer, a well-known thing which has a uniaxial or biaxial stirring blade and was excellent in stirring efficiency is applicable. As the uniaxial agitator, those having a spiral or double spiral blade are suitable. As the biaxial agitator batch type agitator, for example, a planetary mixer, a double-arm kneader, a Banbury mixer or the like using a hook having rotation and revolution as a stirring blade is applied. As a stirrer capable of continuously supplying the suspension and taking out the produced polyketone solution, for example, a screw extruder, a kneader, a thin film stirring type distiller, or the like is applied. It is preferable that all the stirrers have a specification with a high sealing degree. The continuous supply of the suspension and the removal of the polyketone solution using a continuous stirrer can reduce the difference in residence time from the production of the polyketone solution to spinning, and stirring. This is preferable because the machine becomes compact. In addition, a thin film stirring type distiller is preferable among the continuous stirrers in that stirring can be performed while forming a suspension into a film.
[0020]
A process for producing a continuous polyketone solution using a thin-film agitating distillation apparatus will be described with reference to FIG. The suspension is adjusted by the slurry tank 2 and quantitatively charged from the suspension charging port 8 to the thin-film stirred distiller by the liquid feed pump 3. It is possible to adjust the residence time in the thin-film stirring type distillation machine by this input amount. The residence time is preferably 1 to 20 minutes, and more preferably 2 to 10 minutes. The introduced suspension is spread in a film shape along the inner wall of the container by the distribution ring 7, and then stirred and moved downward by the stirring blade 9 as shown in the cross-sectional view. At this time, in the cylinder with the stirring blade, temperature control and pressure reduction control are performed, and water is gradually evaporated from the suspension and removed from the steam outlet 5. It is possible to control the evaporation rate of water vapor according to the charging speed of the suspension, temperature conditions, pressure reduction conditions, and the rotation speed of the stirring blades, and water until a predetermined salt concentration is reached before the suspension reaches the polyketone solution outlet 6. Are removed and a uniform polyketone solution is obtained.
[0021]
【Example】
The present invention will be described in more detail with reference to the following examples, but they are not intended to limit the scope of the present invention.
The measurement method of each measurement value used in the description of the examples is as follows.
(1) Intrinsic viscosity Intrinsic viscosity [η] was determined based on the following defining formula.
“T” and “T” in the definition formula are flow times of a viscosity tube at 25 ° C. of a hexafluoroisopropanol solvent having a purity of 98% or more and a diluted polyketone solution dissolved in the hexafluoroisopropanol solvent. C is the solute weight value in grams in 100 ml of the solvent.
[0022]
[Example 1]
In a 500 ml separable flask, a weight ratio of zinc chloride to sodium chloride = 65/10, a salt concentration = 50% by weight of an aqueous solution 300 g, an intrinsic viscosity [η] = 3.9 dl / g, and substantially 100 repeating units. Molecule 22.2 g of polyketone powder represented by the above formula (1) (polymer ratio = 6.9% by weight) was added and stirred and mixed with a helical blade in an oil bath at a temperature = 50 ° C. for 5 minutes. A suspension was created. Next, the temperature of the oil bath was raised to 100 ° C. with stirring (after 20 minutes), and pressure reduction was started at a degree of pressure reduction = 100 torr, and water was removed from the suspension by evaporation. 60 minutes after the oil bath temperature reached 100 ° C. (dissolution time), a polyketone solution having a salt concentration of 72.6% by weight and a polymer concentration of 9.7% by weight was obtained. The polyketone solution was uniformly transparent and light yellow.
[0023]
[Example 2]
In a 500 ml separable flask, the weight ratio of zinc chloride to sodium chloride = 65/10, the salt concentration = 50% by weight of an aqueous solution 300 g, and the intrinsic viscosity [η] = 9.9 dl / g. 10.5 g of a polyketone powder represented by the above formula (1) (polymer ratio = 3.4 wt%) was put in a mol%, and the mixture was stirred and mixed with a helical blade in an oil bath at a temperature = 50 ° C. for 5 minutes. A suspension was created. Next, the temperature of the oil bath was raised to 100 ° C. with stirring (after 20 minutes), and pressure reduction was started at a degree of pressure reduction = 100 torr, and water was removed from the suspension by evaporation. 50 minutes after the temperature of the oil bath reached 100 ° C. (dissolution time), a polyketone solution having a salt concentration = 73.0 wt% and a polymer concentration = 4.9 wt% was obtained. The polyketone solution was uniformly transparent and almost colorless.
[0024]
[Example 3]
In a 500 ml separable flask, the weight ratio of calcium chloride to zinc chloride = 38/24, 350 g of an aqueous solution having a salt concentration = 40% by weight, and the intrinsic viscosity [η] = 3.9 dl / g. A polyketone powder 25.1 g (polymer ratio = 6.7% by weight) having a mol% of the above formula (1) was added, and the mixture was stirred and mixed with a helical blade in an oil bath at a temperature = 50 ° C. for 5 minutes. A suspension was created. Next, the temperature of the oil bath was raised to 100 ° C. with stirring (after 20 minutes), and pressure reduction was started at a degree of pressure reduction = 100 torr, and water was removed from the suspension by evaporation. 70 minutes after the temperature of the oil bath reached 100 ° C. (dissolution time), a polyketone solution having a salt concentration = 63.2 wt% and a polymer concentration = 10.2 wt% was obtained. The polyketone solution was uniformly transparent and light brown.
[0025]
[Comparative Example 1]
In a 500 ml separable flask, 207 g of an aqueous solution having a weight ratio of zinc chloride to sodium chloride = 65/10 and a salt concentration = 72.6% by weight so as to have the same composition as the polyketone solution obtained in Example 1. And the intrinsic viscosity [η] = 3.9 dl / g and substantially 100 mol% of the repeating unit is charged with 22.2 g of the polyketone powder represented by the formula (1) (polymer concentration = 9.7 wt%), the temperature = The mixture was stirred and mixed with a helical blade for 5 minutes in an oil bath at 50 ° C. Next, the temperature of the oil bath was raised to 100 ° C. with stirring (after 20 minutes). Stirring was performed in a sealed state for 60 minutes (dissolution time) after the temperature of the oil bath reached 100 ° C. The polyketone solution at this time was non-uniform with some white agglomerated particles and yellow.
[0026]
[Comparative Example 2]
In a 500 ml separable flask, an aqueous solution 205 having a weight ratio of zinc chloride to sodium chloride = 65/10 and a salt concentration = 73.0% by weight so as to have the same composition as that of the polyketone solution obtained in Example 2. 0.5 g and intrinsic viscosity [η] = 9.9 dl / g, and substantially 100 mol% of the repeating unit is charged with 10.5 g of polyketone powder represented by the formula (1) (polymer concentration = 4.9 wt%). The mixture was stirred and mixed with a helical blade in an oil bath at a temperature = 50 ° C. for 5 minutes. Next, the temperature of the oil bath was raised to 100 ° C. with stirring (after 20 minutes). Stirring was performed in a sealed state for 50 minutes (dissolution time) after the temperature of the oil bath reached 100 ° C. In this case, the polyketone solution was non-uniform with many white aggregated particles and yellow.
The results of Examples 1 to 3 and Comparative Examples 1 and 2 are summarized in Table 1. Compared to the comparative example, it is possible to produce a uniform polyketone solution with a clearly small dissolution time, and the degree of yellowing is small.
[0027]
[Table 1]
[0028]
[Example 4]
Exeva (manufactured by Shinko Pantech Co., Ltd.) having an inner diameter of the stirring section = 155 mm, a heating inner wall surface area = 0.2 m ² , and a distance between the stirring blade and the inner wall = 2 mm in the thin film stirring type distillation apparatus as shown in FIG. The suspension was continuously supplied and the polyketone solution was taken out continuously. In an aqueous solution having a weight ratio of zinc chloride and sodium chloride of 65/10 and a salt concentration of 30% by weight, the intrinsic viscosity [η] = 5.9 dl / g and substantially 100 mol% of the repeating unit is represented by the formula (1). The indicated polyketone powder was mixed in the slurry tank 2 so that the polymer ratio was 4.2% by weight, and a suspension heated to 80 ° C. was prepared. This suspension is continuously sent to the suspension inlet 8 at 45 kg / hour, the temperature of the heating jacket 4 is 100 ° C., the degree of vacuum is 100 torr, and the number of rotations of the stirring shaft is 500 rpm. Adjustment was performed and a polyketone solution was continuously obtained from the polyketone solution outlet. At this time, the salt concentration of the polyketone solution was 73 wt%, the polymer concentration was 9.6 wt%, and it was uniformly transparent and almost colorless.
[0029]
【The invention's effect】
Suppresses the formation of polyketone aggregates when dissolving polyketone in an aqueous solution consisting of at least one selected from zinc, calcium, thiocyanate, and iron salt, and produces a uniform polyketone solution at high speed It becomes possible to do. The effect is particularly great when a polyketone solution is produced using a high molecular weight polyketone or when a high-concentration polyketone solution is produced.
[Brief description of the drawings]
FIG. 1 is a partial longitudinal cross-sectional view of a thin-film agitating distillation machine and an enlarged cross-sectional view taken along lines a and b.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Motor 2 Slurry tank 3 Feeding pump 4 Heating jacket 5 Steam outlet 6 Polyketone solution outlet 7 Distribution ring 8 Suspension inlet 9 Stirring blade 10 Stirring shaft 11 Film-like suspension

Claims (4)

A polyketone having 95% by mole or more of repeating units represented by the following structural formula (1) is dissolved in an aqueous solution containing at least one salt selected from zinc salt, calcium salt, thiocyanate, and iron salt. In the method for producing a polyketone solution , a powdery polyketone having a longest part of 0.01 mm or more and 5 mm or less is dispersed in the salt aqueous solution having a salt concentration of 0.01 wt% or more and 59 wt% or less to suspend the polyketone. A method for producing a polyketone solution comprising separating and removing water from the suspension until the salt concentration is 60 wt% or more and 90 wt% or less after the solution is prepared.
The method for producing a polyketone solution according to claim 1 , wherein water is separated and removed from the polyketone suspension by evaporating the water under reduced pressure. The method for producing a polyketone solution according to claim 1 or 2 , wherein the polyketone suspension is spread in a film shape and water is separated and removed from the suspension. Method for producing a polyketone solution according to any one of claims 1 to 3, characterized in that the extraction of the feed and polyketone solution of suspension of polyketone continuously.