KR100993871B1 - Method of manufacturing aromatic polyamide filament - Google Patents

Abstract

The present invention relates to a method for producing an wholly aromatic polyamide filament, comprising: a second solvent in which a polymerization solvent in which an aromatic dieside chloride and an aromatic diamine are dissolved in a polymerization reactor is prepared in a polymerization reactor. Compared to the stirring section (II), when the screw rotation speed is relatively high and the temperature and shear rate are relatively low, the first stirring section (I) and (ii) the first stirring section (I) It is characterized in that the mixing and polymerization while passing through the second stirring section (II) having a relatively low rotational speed of the screw and a relatively high temperature and shear rate.

The present invention improves the polymer intrinsic viscosity to 5.6 to 9.0 dL / g by slowing down the gel formation time when polymerizing the wholly aromatic polyamide polymer.

Therefore, the wholly aromatic polyamide filament produced by the present invention exhibits improved physical properties such as strength and elastic modulus.

Wholly aromatic polyamide, filament, polymer, gel formation, retardation, intrinsic viscosity, strength, elastic modulus.

Description

Method of manufacturing aromatic polyamide filament {Method of manufacturing aromatic polyamide filament}

1 is a process schematic diagram of making a wholly aromatic polyamide filament in a wet-wet spinning manner.

Figure 2 is a schematic cross-sectional view of the reactor for polymerization used in the present invention.

Figure 3 is a graph showing the intrinsic viscosity change of the polymer with polymerization time (polymerization time-intrinsic viscosity graph).

* Description of symbols on the main parts of the drawings

10: monomer and polymerization solvent storage tank

11: monomer and polymerization solvent supply pipe

20: polymerization reactor 21: high speed rotary screw

22: high speed rotation motor 23: low speed rotation screw

24: low speed rotary motor 30: spinning solution reservoir

40: spinneret 50: coagulation bath

60: washing device 70: drying device

80: heat treatment apparatus 90: winder

Ⅰ: 1st Stirring Section Ⅱ: 2nd Stirring Section

A: polymerization time-intrinsic viscosity graph according to the present invention

B: polymerization time-intrinsic viscosity graph according to the conventional method

a: gel generating point b: liquid crystal state

The present invention relates to a method for producing a wholly aromatic polyamide filament, and more particularly to a method for producing a wholly aromatic polyamide filament having high strength and high elastic properties.

The wholly aromatic polyamide filaments are prepared by polymerizing aromatic diamines and aromatic dieside chlorides in a polymerization solvent containing N-methyl-2-pyrrolidone, as disclosed in U.S. Patent Nos. 3,869,492 and 3,869,430. Preparing a polyamide polymer; dissolving the polymer in a concentrated sulfuric acid solvent to produce a spinning stock solution; spinning the spinning stock solution from a spinneret and passing the spun spinning material through a non-coagulating fluid layer into a coagulating bath. And filaments are formed, and the filaments are washed with water, dried and heat treated.

1 is a process schematic diagram of making a wholly aromatic polyamide filament in a conventional wet and dry spinning manner.

In the conventional method, when preparing the wholly aromatic polyamide polymer, a polymerization reactor in which one screw is installed to rotate a polymerization solvent in which an aromatic dieside chloride as a polymerization monomer and an aromatic diamine as a polymerization monomer are dissolved at a constant speed ( 20) due to agitation and polymerization in the polymerization, it was not possible to slow down the gel formation time during polymerization, resulting in a low intrinsic viscosity of the polymer at a level of 5.5 dℓ / g.

The wholly aromatic polyamide polymer prepared by the conventional method has a low intrinsic viscosity to 6.0 dL / g level, resulting in a decrease in strength and elastic modulus of the final product, wholly aromatic polyamide filament.

The present invention is to produce a wholly aromatic polyamide filament with improved strength and elastic modulus by solving such a conventional problem.

The present invention is to improve the strength and elastic modulus of the final product of the wholly aromatic polyamide filament by increasing the intrinsic viscosity of the polymer to the level of 5.6 ~ 9.0dℓ / g by slowing the gel formation time when polymerizing the wholly aromatic polyamide polymer It is a technical problem.

In order to solve the above technical problem, the present invention polymerizes an aromatic diamine and an aromatic dieside chloride in a polymerization solvent containing N-methyl-2-pyrrolidone to prepare a wholly aromatic polyamide polymer, and the polymer is concentrated sulfuric acid. Dissolving in a solvent to prepare a spinning stock solution, spinning the spinning stock from the spinneret, and passing the spinning material through a non-coagulating fluid layer into a coagulation bath to form a filament; and washing, drying, and heat treatment of the filament. In the preparation of the wholly aromatic polyamide filament through the process of preparing, the polymerizing solvent in which the aromatic dieside chloride and the aromatic diamine are dissolved at the time of preparing the wholly aromatic polyamide polymer is separated from the reactor for polymerization. The rotational speed of the screw relative to the two stirring sections (Ⅱ) , The screw rotation speed is relatively low and the temperature and shear rate are relatively low compared to the first stirring section (I) and (ii) the first stirring section (I), which are high in temperature and relatively low in shear rate. It is characterized by mixing and polymerizing while passing through the second stirring section (II), which is relatively high.

Hereinafter, with reference to the accompanying drawings, it will be described in detail.

First, in the present invention, an aromatic diamine and an aromatic dieside chloride are polymerized in a polymerization solvent containing N-methyl-2-pyrrolidone to prepare a wholly aromatic polyamide polymer.

The aromatic diamine is P-phenylenediamine and the like, and the aromatic dieside chloride is terephthaloyl chloride and the like.

The polymerization solvent is N-methyl-2-pyrrolidone or the like in which calcium chloride is dissolved.

In the present invention, when manufacturing the wholly aromatic polyamide polymer as described above, as shown in Fig. 2, the rotational speed of the screw is divided into a polymerization solvent in which the aromatic dieside chloride and aromatic diamine are dissolved in the polymerization reactor. Is the first stirring section (I) having a relatively high temperature and relatively low temperature and shear rate, and (ii) a second stirring with a relatively low screw rotation speed and a relatively high temperature and shear rate. It is characterized by mixing and polymerizing while passing section (II) one after the other.

2 is a schematic cross-sectional view of a polymerization reactor used in the present invention.

More specifically, in the polymerization reactor 20, a high speed rotating screw 21 and a high speed rotating motor 22 are provided from a central part to a portion where a supply pipe 11 into which a polymerization monomer and a polymerization solvent are introduced is installed, as shown in FIG. The first stirrer section (I) is installed, and the second stirrer section (II) on which the low speed rotation screw (23) and the low speed rotation motor (24) are installed.

In other words, in the polymerization reactor 20 used in the present invention, two high-speed rotating screws 21 having relatively high rotational speeds and two low-speed rotating screws 23 having relatively low rotational speeds are installed at both sides of the central part, respectively. The high speed rotation screw 21 is located on the side where the polymerization monomer supply pipe 11 is installed, and the low speed rotation screw 23 is located on the opposite side thereof.

On the other hand, the temperature in the first stirring section (I) is 0 ~ 30 ℃, shear rate (Shear rate) 1 ~ 100 / sec is relatively lower than the temperature and shear rate of the second stirring zone (II).

The temperature in the second stirring section II is 30 to 70 ° C. and the shear rate is 10 to 1,000 / sec, which is relatively higher than the temperature and shear rate of the first stirring section I.

The polymerization monomer and the polymerization solvent introduced into the polymerization reactor are stirred and polymerized to a sol state in the first stirring zone (I), and gradually to a gel state in the second stirring zone (II) as the polymerization proceeds. Becomes

Therefore, in the present invention, as shown in FIG. 3, the gel formation time is delayed compared to the conventional method using one screw, and as a result, the intrinsic viscosity of the polymer is up to 5.6 to 9.0 dℓ / g. Greatly improved.

3 is a graph showing the change in intrinsic viscosity of a polymer with polymerization time (polymerization time-intrinsic viscosity graph).

In Figure 3 A graph is a polymerization time-intrinsic viscosity graph according to the present invention, B graph is a polymerization time-intrinsic viscosity graph according to the conventional method.

On the other hand, the gel formed in the second stirring zone (II) does not flow back to the first stirring zone (I) because the screw rotation speed of the first stirring zone is faster than the screw rotation speed of the second stirring zone.

Other polymerization conditions of the polymer are the same as the known polymerization conditions disclosed in US Pat. No. 3,869,429 and the like.

One example of preparing the polymer is a solution in which one mole of para-phenylenediamine is dissolved in N-methyl-2-pyrrolidone containing about one mole of calcium chloride and one mole of terephthaloyl chloride as described above. It is charged into a polymerization reactor 20 having a first stirring zone (I) and a second stirring zone (II), followed by stirring to prepare a gel polymer, which is ground, washed with water and dried to prepare a fine powder polymer. . In this case, the terephthaloyl chloride may be introduced into the reactor 20 for polymerization in two stages.

Next, the spinning solution is prepared by dissolving the wholly aromatic polyamide polymer prepared as described above in a concentrated sulfuric acid solvent, and then spinning the spinning solution through the spinneret 40 as shown in FIG. The spinning is passed through a non-coagulating fluid layer into the coagulating bath 50 to form a filament, followed by washing, drying and heat treating the formed filament to produce a wholly aromatic polyamide filament. 1 is a process schematic diagram of producing a wholly aromatic polyamide filament by wet spinning spinning spinning solution.

The concentration of concentrated sulfuric acid used in the production of the spinning stock solution is preferably 97% to 100%, and chlorosulfuric acid, fluorosulfuric acid, and the like may also be used.

At this time, when the concentration of sulfuric acid is less than 97%, the solubility of the polymer is reduced and the liquid crystalline expression of the anisotropic solution becomes difficult. Therefore, it is difficult to manufacture a spinning solution having a constant viscosity, which makes it difficult to control the process during spinning and to provide mechanical properties of the final fiber. Can be degraded.

On the other hand, if the concentration of the concentrated sulfuric acid exceeds 100%, gwari (過離) because in oleum containing SO _3, as well as undesirable phase handled becomes an SO ₃ over takes place is partly dissolved in the polymer spinning solution to the inadequate and In addition, even if the fiber is obtained by spinning, there may be a problem that the internal structure of the fiber is not dense, the appearance is not gloss, and the speed of sulfuric acid diffused into the coagulation solution is lowered, thereby lowering the mechanical properties of the fiber.

On the other hand, it is preferable for the fiber property that the concentration of the polymer in the spinning stock solution is 10 to 25% by weight.

However, the present invention does not specifically limit the concentration of concentrated sulfuric acid and the concentration of the polymer in the spinning stock solution.

The non-coagulating fluid layer may mainly be an air layer or an inert gas layer.

The length of the non-coagulating fluid layer, that is, the distance between the bottom surface of the spinneret 40 and the surface of the coagulating liquid contained in the coagulating liquid bath 50 is preferably 0.1 to 15 cm to improve the properties of the radioactive or filament.

The coagulant liquid in the coagulant bath 50 may overflow. As the coagulating solution, water, brine or an aqueous sulfuric acid solution having a concentration of 70% or less is used.

Spinning wind speed is 300 to 1500m / min level.

Hereinafter, the present invention will be described in detail through Examples and Comparative Examples.

However, the present invention is not limited to the scope of protection by the following examples.

Example  One

An aromatic diamine solution was prepared by maintaining 1,000 kg of N-methyl-2-pyrrolidone at 80 ° C. and dissolving 80 kg of calcium chloride and 48.67 kg of para-phenylenediamine.

A molten terephthaloyl chloride having the same molar amount as the aromatic diamine solution and para-phenylenediamine prepared as described above is provided with a high speed rotating screw 21 and a high speed rotating motor 22 as shown in FIG. 2. It was introduced into the polymerization reactor 20 divided into the stirring zone (I), the second stirring zone (II) in which the low speed rotating screw 23 and the low speed rotating motor 24 were installed, and then the first stirring zone ( A poly (para-phenylene terephthalamide) polymer having an intrinsic viscosity of 8.0 dL / g was prepared by stirring and polymerizing while passing through I) and the second stirring zone (II).

At this time, the temperature in the first stirring zone (I) was 10 ° C., the shear rate was 50 / sec, the temperature in the second stirring zone (II) was 50 ° C., and the shear rate was 100 / sec.

Next, the prepared polymer was dissolved in 99% concentrated sulfuric acid to prepare an optically anisotropic radiation stock solution having a polymer content of 18% by weight.

Next, after spinning the spinning solution prepared as described above through the spinneret 40 as shown in Figure 1, the coagulated liquid bath containing water that is the coagulated liquid through the air layer of the radiated spinning 7mm ( 50) to form a filament.

Next, a poly (para-phenylene terephthalamide) filament was prepared by repeating the process of washing the filament formed as described above with water and drying for 5 seconds at 550 ° C. for 5 seconds.

Table 1 shows the results of measuring the strength and modulus of the prepared poly (para-phenylene terephthalamide) filament.

Comparative Example  One

 The intrinsic viscosity was 5.3 dL under the same conditions as in Example 1 except that the aromatic diamine solution prepared in Example 1 and the molten terephthaloyl chloride were fed into a conventional polymerization reactor equipped with one screw, followed by stirring and polymerization. A poly (para-phenyleneterephthalamide) filament of / g was prepared.

At this time, the temperature of the polymerization reactor was 30 ℃, shear rate 100 / sec.

The results of measuring the strength and elastic modulus of the prepared poly (para-phenylene terephthalamide) filament are shown in Table 1.

<Table 1> Filament Property Evaluation Results

division

Example 1

Comparative Example 1

Strength (g / d)

28

22

Modulus of elasticity (g / d)

890

740

In the present invention, the strength and elastic modulus were measured by the following method.

Strength (g / d)

Instron tester (Instron Engineering Corp, Canton, Mass) was used to measure the strength (g) when the sample yarn is broken using a sample yarn having a length of 25cm and then divided by the denier of the sample yarn to obtain the strength. The said intensity | strength was made into the average value after testing 5 times. At this time, the tensile speed was 300 mm / min, the ultra-load was fineness × 1 / 30g.

Modulus of elasticity (g / d)

The stress-strain curve of the sample yarn is obtained under the above-described strength measurement conditions, and then calculated from the slope on the stress-strain curve.

Intrinsic viscosity

A sample solution is prepared by dissolving 0.1250 g of a sample (polymer or filament) in 25.0 ml of 98% sulfuric acid. Next, the flow time of the sample solution was measured with a capillary viscometer (Cannon Fenske Viscometer: Type 300) in a 30 ° C. constant temperature water bath, and the flow time of the sample solution was then measured. ) Is divided by the flow time of the solvent (sulfuric acid solution) (the number of falling seconds) to determine the relative viscosity (ηrel).

Next, the intrinsic viscosity is calculated by dividing the relative viscosity ηrel by the concentration of the sample solution.

The present invention can delay the gel formation time during the polymer polymerization, thereby increasing the intrinsic viscosity of the polymer to a level of 8.0 dℓ / g.

For this reason, the wholly aromatic polyamide filament produced by the present invention greatly improves the strength and elastic modulus.

Claims (7)

Preparing a wholly aromatic polyamide polymer by polymerizing an aromatic diamine and an aromatic dieside chloride in a polymerization solvent containing N-methyl-2-pyrrolidone; and dissolving the polymer in a concentrated sulfuric acid solvent to prepare a spinning stock solution. Spinning the spinning stock solution from the spinneret and passing the spinning material through a non-coagulating fluid layer into a coagulation bath to form a filament; and washing the filament with water, drying and heat treatment to form a wholly aromatic polyamide filament. In the preparation, when preparing the wholly aromatic polyamide polymer, the polymerization solvent in which the aromatic dieside chloride and the aromatic diamine are dissolved is compared with the second stirring section (II) which is divided in the polymerization reactor. Rotation speed is relatively high and temperature and shear rate are relatively low. Compared to the first stirring section (I) and (ii) the first stirring section (I), the second stirring section (II) having a relatively low rotational speed of the screw and a relatively high temperature and shear rate is shown. A method for producing a wholly aromatic polyamide filament, characterized in that the mixture is mixed and polymerized while passing in turn. The method for producing a wholly aromatic polyamide filament according to claim 1, wherein the temperature in the first stirring zone (I) is 0 to 30 ° C and the shear rate is 1 to 100 / sec. The method for producing the wholly aromatic polyamide filament according to claim 1, wherein the temperature in the second stirring zone (II) is 30 to 70 ° C and the shear rate is 10 to 1,000 / sec. The process for producing an wholly aromatic polyamide filament according to claim 1, wherein the intrinsic viscosity of the wholly aromatic polyamide polymer is 5.6 to 9.0 dL / g. The method for producing an wholly aromatic polyamide filament according to claim 1, wherein calcium chloride is contained in the polymerization solvent. The process for producing a wholly aromatic polyamide filament according to claim 1, wherein the aromatic diamine is para-phenylenediamine. The method for producing a wholly aromatic polyamide filament according to claim 1, wherein the aromatic dieside chloride is terephthaloyl chloride.

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