KR20090090102A - Method of manufacturing aramid pulp - Google Patents

Abstract

A manufacturing method of aramid pulp is provided to prevent a cutting failure of the pulp due to foreign materials in spinning dope by using a die for manufacturing a film instead of a spinneret. A manufacturing method of aramid pulp includes the following steps of: discharging spinning dope through a die(20) for manufacturing a film after dissolving an aramid polymer in sulfuric acid; producing an aramid film through a conjugation, a washing, a neutralization, and a drying processes; and pulverizing the aramid film. An ejected material is passes through an air layer before conjugation of the material.

Description

Method of manufacturing aramid pulp {Method of manufacturing aramid pulp}

The present invention relates to a method for producing aramid pulp, and more particularly, to a method for producing aramid pulp having high productivity, simplifying foreign matter removal process in spinning dope, and having a high specific surface area of the produced aramid pulp.

Aramid pulp is widely used as a gasket or automobile brake lining material because of its excellent heat resistance and friction characteristics.

In the conventional method for producing aramid pulp, the spinning filaments prepared by dissolving the aramid polymer in sulfuric acid are discharged into the air through the spinneret for filament production (4), as shown in FIG. 3, and then discharged filaments into the coagulation bath (5). After coagulation by passing through the washing and neutralizing roller (6, 7, 8) while passing through the washing, neutralizing and drying in order to prepare aramid filament, and then aramid filament was prepared by grinding the aramid pulp.

3 is a process schematic diagram of manufacturing conventional aramid filaments.

More specifically, the aramid (fully aromatic polyamide) filaments include N-methyl-2-pyrrolidone and aromatic diamines as disclosed in U.S. Patent Nos. 3,869,492 and 3,869,430, etc. Preparing a wholly aromatic polyamide polymer by polymerizing in a polymerization solvent, dissolving the polymer in a concentrated sulfuric acid solvent to prepare a spinning solution, and spinning the spinning solution from a spinneret to form a non-coagulating fluid layer. It is produced through the process of forming a filament by passing through the coagulation bath, and the steps of washing, drying and heat treating the filament.

In the conventional method for producing aramid pulp, the spinning rate of the aramid filament being spun by the foreign material in the spinning dope increases when the spinning dope is spun through the spinneret for filament manufacturing (4) to produce aramid filament, thereby greatly reducing productivity. In order to prevent the cutting rate from being lowered, there was a need to more thoroughly remove foreign substances in the spinning dope, and the specific surface area of the manufactured aramid pulp has a low specific surface area. there was.

The present invention is to provide a method for producing aramid pulp in which the productivity is high, there is no decrease in productivity even if the foreign matter removal process in the spinning dope is not thoroughly managed, and the aramid pulp produced has a high specific surface area.

In the method for producing aramid pulp according to the present invention, the spinning dope prepared by dissolving the aramid polymer in sulfuric acid is discharged in a film form through the die 20 for film production, and then the discharged discharge is solidified, washed, neutralized and dried. Manufacturing an aramid film; It includes; a step of grinding the aramid film.

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated in detail.

The present invention first discharges the spinning dope prepared by dissolving the aramid polymer in sulfuric acid as shown in Figure 1 through a film forming die 20 in the form of a film and then solidified, washed, neutralized and dried To prepare an aramid film.

1 is a process schematic diagram of producing an aramid film of the present invention.

As shown in FIG. 2, the film manufacturing die 20 has a structure in which a film sheet discharge port 21 is formed in the longitudinal direction of the die 20.

FIG. 2 is a bottom view of the die 20 for manufacturing a film in FIG. 1.

In the present invention, it is preferable to pass the discharge into the air layer before solidifying the discharge, and to solidify the discharge by spraying the coagulation liquid in a thin plate with the coagulation liquid injection device 30 on the discharge passing through the air layer. desirable.

The coagulating solution is water, brine or sulfuric acid solution.

Next, in the present invention, the aramid film prepared as described above is pulverized with a conventional mill to produce an aramid film.

In the present invention, since the spinning dope is discharged through the film manufacturing die 20 having a structure as shown in FIG. 2, compared to the method of spinning the spinning dope using the spinneret 4 for manufacturing the filament, the foreign material in the spinning dope The film cutting rate during discharge by the ink is significantly reduced, and the productivity is improved.

In addition, the present invention is more simplified the process of removing the foreign matter in the spinning dope because the cut ratio of the film due to the foreign matter in the spinning dope as described above.

In addition, the aramid pulp prepared by pulverizing the aramid film as in the method of the present invention has a specific surface area higher than that of the aramid pulp prepared by pulverizing the conventional aramid filaments, and when used as a material such as a gasket, the adhesion to the matrix resin component is greatly improved.

In the present invention, the specific surface area of aramid pulp was measured by using Micromeritics (Flowsorb II 2300). This applies to measuring the area of the surface to the weight of materials with non-uniform surfaces. First, the U-shaped glass tube into which the sample is to be placed is strongly passed through the nitrogen to remove moisture to accurately measure the weight of the glass tube. Subsequently, nitrogen gas is adsorbed to the sample by injecting nitrogen gas into one inlet of the U-shaped glass tube filled with the sample for a predetermined time and discharging nitrogen gas to the other inlet, and calculate the surface area of the sample by calculating the amount of nitrogen gas adsorbed on the sample. .

Specific surface area (㎡ / g) = surface area (㎡) / sample weight (g)

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

1,000 kg of N-methyl-2-pyrrolidone was maintained at 80 ° C. and 80 kg of calcium chloride and 48.67 kg of para-phenylenediamine were dissolved therein to prepare an aromatic diamine solution (B).

The aromatic diamine solution (B) was introduced into the polymerization reactor 20, and at the same time, para-phenylenediamine and an equimolar amount of molten terephthaloyl chloride (A) were introduced into the polymerization reactor 20. Stirring produced a poly (para-phenylene terephthalamide) polymer having an intrinsic viscosity of 6.8.

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

Next, after the spinning dope prepared as described above is discharged through the die 20 for film production as shown in FIG. ) Was sprayed into a thin plate, and then washed with water, neutralized and dried to prepare a poly (para-phenylene terephthalamide) film.

Next, the poly (para-phenylene terephthalamide) film prepared as described above was pulverized with a grinder to prepare poly (para-phenylene terephthalamide) pulp.

The specific surface area of the prepared poly (para-phenylene terephthalamide) pulp was measured by the measuring method described above, and the result was 20 m 2 / g.

Comparative Example  One

1,000 kg of N-methyl-2-pyrrolidone was maintained at 80 ° C. and 80 kg of calcium chloride and 48.67 kg of para-phenylenediamine were dissolved therein to prepare an aromatic diamine solution (B).

The aromatic diamine solution (B) was introduced into the polymerization reactor 20, and at the same time, para-phenylenediamine and an equimolar amount of molten terephthaloyl chloride (A) were introduced into the polymerization reactor 20. Stirring produced a poly (para-phenylene terephthalamide) polymer having an intrinsic viscosity of 6.8.

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

Next, after spinning the spinning stock solution prepared as described above through the spinneret for manufacturing filament (4) as shown in Figure 3, the spinning material is passed through the air layer of 7mm containing water that is a coagulation solution The poly (para-phenyleneterephthalamide) filaments were prepared by passing through a coagulation bath (5), followed by washing with water, neutralization and drying.

Next, the poly (para-phenylene terephthalamide) filaments prepared as described above were pulverized with a grinder to prepare poly (para-phenylene terephthalamide) pulp.

The specific surface area of the prepared poly (para-phenylene terephthalamide) pulp was measured by the above-described measuring method, and the result was 13 m 2 / g.

1 is a process schematic diagram of preparing an aramid film in the method for producing aramid pulp according to the present invention.

FIG. 2 is a bottom view of the die 20 for manufacturing a film in FIG. 1. FIG.

Figure 3 is a process schematic diagram of manufacturing the conventional aramid filament

* Code description for main parts of the drawings

3, 10: polymer polymerization tube 20: die for film production

30: coagulating liquid injection device 40: coagulated liquid injected

50: aramid film winding roller

21: film sheet discharge port of the die for film production

4: spinneret for manufacturing filament 5: solidification bath

6,7,8: flush and neutral roller

9: filament winding roller

Claims (4)

Discharging the spinning dope prepared by dissolving the aramid polymer in sulfuric acid in the form of a film through the die 20 for film production, and then coagulating, washing, neutralizing, and drying the discharged discharge to produce an aramid film; Aramid pulp manufacturing method comprising a; a step of grinding the aramid film. The method for producing aramid pulp according to claim 1, wherein the discharge is passed into an air layer before the discharge is solidified. The method for producing aramid pulp according to claim 1, wherein the discharge is solidified by spraying the coagulation solution with a coagulation solution injector (30). The method for producing aramid pulp according to claim 3, wherein the coagulating solution is one selected from water, brine and sulfuric acid aqueous solution.

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