KR20160071713A - A manufacturing device for aramid fiber and the method of manufacturing it - Google Patents

Abstract

The present invention relates to an apparatus for producing an aramid fiber and a method for producing the aramid fiber thereby. More specifically, the present invention relates to a method for producing an aramid fiber. The formation of unevenness at the bottom portion of a coagulation tube facilitates generation of warm current, thereby maximizing extraction of a residual sulphate and minimizing reduction in material properties such as tensile strength and elongation.

Description

FIELD OF THE INVENTION [0001] The present invention relates to a method for producing aramid fibers,

The present invention relates to an apparatus for producing an aramid fiber and a method for producing the aramid fiber by the method. More specifically, the present invention relates to a method for producing an aramid fiber, The present invention relates to an apparatus for producing an aramid fiber and a method for producing an aramid fiber by the apparatus.

The wholly aromatic polyamide filaments are prepared by polymerizing an aromatic diamine and an aromatic diacid chloride in a polymerization solvent containing N-methyl-2-pyrrolidone as disclosed in U.S. Patent No. 3,869,492 and U.S. Patent No. 3,869,430, A method for producing an aromatic polyamide polymer, comprising the steps of: preparing an aromatic polyamide polymer; dissolving the polymer in a concentrated sulfuric acid solvent to prepare a spinning solution; spinning the spinning solution through a spinneret and spinning the spinning solution through a non- To form a filament, and a step of washing, drying and heat-treating the filament.

Para-aramid fibers have excellent properties such as high strength, high elasticity and low shrinkage. In particular, they have a strength of about 5mm and a thickness of about 2 tons, which is strong enough to lift a car, It is used for various purposes in high-tech industries such as the field.

In general, the aramid fiber is produced by a process comprising the steps of: preparing an aromatic polyamide polymer; dissolving the aromatic polyamide polymer in a sulfuric acid solvent to prepare a dope; extruding the dope through a spinneret; Followed by a solidifying step.

The aramid fiber has a skin-core structure having a higher elastic modulus of the surface layer than the elastic modulus of the core layer, so that when stress is applied to the aramid fiber, stress is mostly concentrated on the surface layer. Therefore, the physical properties of the surface layer of the aramid fiber are important factors in determining the strength of the aramid fiber.

Korean Patent Laid-Open Publication No. 2013-75216 describes an apparatus for producing an aramid fiber. The technique includes a dope supply unit; Spinneret; A coagulating unit; Can Details; Wherein the dope extruded from the spinneret is solidified while passing through the air gap between the spinneret and the coagulation bath, the coagulation bath, and the coagulation tube in order to form the multifilament .

At this time, the solidification tube has a plurality of grooves extending in a direction parallel to the longitudinal direction of the solidification tube.

The apparatus is characterized in that the composition and temperature of the coagulating liquid when injecting the second coagulating liquid through the jetting port are performed under the same conditions as the injection of the first coagulating liquid and suppress the occurrence of turbulence. Due to the above-mentioned structure, the aramid fiber can be spun at a rate of more than 600 mpm (meter per minute). However, since the solvent in the filament, especially the sulfuric acid, is not easily extracted, the residual salt content in the final produced aramid fiber is high, Is lowered.

Korean Patent Publication No. 2013-0075216 Korea Patent Publication No. 2007-0072042 Korean Patent No. 10-1192918 U.S. Patent No. 3,869,492 United States Patent No. 3,869,430 Japanese Patent No. 04757200

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In order to solve the above-mentioned problems, the present invention is to solve the above-mentioned problems by providing a method for producing a coagulating agent, which comprises the step of coagulating a dope extruded through a cage, And an apparatus for producing an aramid fiber.

The present invention also provides an apparatus for producing an aramid fiber which can prevent deterioration of properties such as tensile strength and elongation of aramid fibers by differentiating the temperature and composition of the coagulating liquid when injecting the second coagulating liquid through the jetting port, Another purpose is to do.

Other objects and advantages of the present invention may be realized and attained by the structure particularly pointed out in the written description of the invention and the appended claims.

In order to solve the above problems,

A dope supply unit; Spinning detention; Wherein the coagulating unit comprises: a coagulation vessel which is positioned below the spinneret and contains a coagulating liquid; A first coagulation tube positioned below the coagulation bath to provide a discharge passage for the coagulation liquid; An injection port attached to one side of the first coagulation tube at an angle of 20 to 40 degrees to inject a second coagulating solution; A second solidification tube attached to a lower end portion of the injection port; And the second coagulation tube has a concavo-convex shape, the apparatus provides an apparatus for producing an aramid fiber as a means for solving the problem.

Wherein the second solidification tube has a cross-sectional area of 8 to 11 mm in diameter and a concavo-convex radius of 0.5 to 1.5 mm,

And the sum of the lengths of the first and second coagulation tubes is 150 mm.

Further, the present invention is characterized in that the composition and temperature of the primary coagulating liquid and the solvent are different in the secondary coagulating liquid injected through the injection port.

According to the apparatus for producing an aramid fiber of the present invention, turbulence is generated in the course of solidification of a dope extruded through a cage, thereby maximizing the extraction of residual salts such as sulfuric acid and effectively reducing the physical properties of the aramid fiber due to the presence of the residual salt .

1 is a view schematically showing features of an apparatus for producing an aramid fiber of the present invention.

Best Mode for Carrying Out the Invention The present invention will be described in more detail based on the drawings and examples.

While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail. It should be understood, however, that the invention is not intended to be limited to the particular embodiments, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

1 is a view schematically showing features of an apparatus for producing an aramid fiber of the present invention. As shown, the apparatus for producing an aramid fiber of the present invention comprises a dope supply unit; Spinning detention; As a solidifying portion; Wherein the solidifying portion comprises: a coagulation bath located at a lower portion of the spinneret and containing a coagulating solution; A first coagulation tube positioned below the coagulation bath to provide a discharge passage for the coagulation liquid; An injection port attached to one side of the first coagulation tube at an angle of 20 to 40 degrees to inject a second coagulating solution; A second solidification tube attached to a lower end portion of the injection port; And the second solidification tube has a concavo-convex shape.

The dope containing the aromatic polyamide supplied from the dope supply portion is extruded through the spinneret and then solidified while passing through the solidifying portion to form the multifilament.

The aromatic polyamide is a para-aramid having a high strength and a high modulus of elasticity, and is a polyparaphenylene terephthalamide (PPD-T), a poly (4,4'-benzanilide terephthalamide), a poly , 4'-biphenylene-dicarboxylic acid amide), poly (paraphenylene-2,6-naphthalene dicarboxylic acid amide), or a mixture of two or more thereof.

The aromatic polyamide can be produced by the following method.

First, an inorganic salt is added to an organic solvent to prepare a polymerization solvent. Examples of the organic solvent include N-methyl-2-pyrrolidone (NMP), N, N'-dimethylacetamide (DMAc), hexamethylphosphoramide (HMPA) Methyl urea (TMU), N, N-dimethylformamide (DMF) or mixtures thereof may be used. As the inorganic salt, CaCl2, LiCl, NaCl, KCl, LiBr, KBr, or a mixture thereof may be used. The inorganic salt is added in order to increase the polymerization degree of the aromatic polyamide. However, since the inorganic salt which is not dissolved when the inorganic salt is added in an excess amount may be present in the polymerization solvent, the content of the inorganic salt in the polymerization solvent is preferably 10% by weight or less. Since the solubility of the inorganic salt in the organic solvent is poor, water is added to completely dissolve the inorganic salt, and then the water is removed through a dehydration process, whereby a final polymerization solvent can be prepared.

Next, the aromatic diamine is dissolved in the polymerization solvent to prepare a mixed solution. The aromatic diamine may be para-phenylenediamine, 4,4'-diaminobiphenyl, 2,6-naphthalenediamine, 1,5-naphthalenediamine, or 4,4'-diaminobenzanilide.

Then, a primary polymerization is carried out by adding a predetermined amount of aromatic diacid halide to the mixed solution while stirring the mixed solution. The aromatic diacid halide may be terephthaloyl dichloride, 4,4'-benzoyl dichloride, 2,6-naphthalene dicarboxylic acid dichloride, or 1,5-naphthalene dicarboxylic acid dichloride. Through the primary polymerization, a prepolymer is formed in the polymerization solvent.

Subsequently, an aromatic diacid halide is further added to the above polymerization solvent to carry out a secondary polymerization, and through this secondary polymerization, an aromatic polyamide is finally obtained. The aromatic polyamide may be selected from the group consisting of polyparaphenylene terephthalamide (PPD-T), poly (4,4'-benzanilide terephthalamide), poly (paraphenylene- 4,4'-biphenylene-dicarboxylic acid amide), or poly (paraphenylene-2,6-naphthalene dicarboxylic acid amide).

Next, an alkaline compound such as NaOH, Li2CO3, CaCO3, LiH, CaH2, LiOH, Ca (OH) 2, Li2O, CaO or the like is added to the polymerization solution to neutralize the hydrochloric acid generated during the polymerization reaction. On the other hand, it may be advantageous to carry out the subsequent processes by adding water to the polymerization solution obtained through the primary and secondary polymerization processes to prepare a slurry state to improve its flowability. At this time, the neutralization step and the slurry production step may be performed simultaneously by adding water in which the alkali compound is dissolved to the polymerization solution.

Subsequently, the polymerization solvent is extracted from the polymerization solution. Such an extraction process is most effective and economical to perform using water. For example, a filter may be installed in a bath equipped with an outlet, and the polymer may be placed on the filter, and then water may be poured to discharge the polymerization solvent contained in the polymer together with water to the outlet. On the other hand, if the particle size of the aromatic polyamide present in the polymerization solution is too large, it takes a long time to extract the polymerization solvent and the productivity may be lowered. Therefore, the step of pulverizing the aromatic polyamide may be performed before the polymerization solvent extraction step.

Then, the water remaining in the aromatic polyamide is removed through dehydration and drying processes.

The dope prepared by the above method is supplied to the spinneret through the dope supplying section and then extruded. The spinneret has a plurality of capillaries having a diameter of 0.1 mm or less. If the diameter of the capillary formed in the spinneret exceeds 0.1 mm, the molecular orientation of the resulting monofilament is deteriorated, resulting in a decrease in the strength of the multifilament.

The concavo-convex shape is formed in order to promote the generation of turbulence. The second coagulation tube has a sectional area of 8 to 11 mm and a concavity radius of 0.5 to 1.5 mm.

The sum of the lengths of the first and second coagulation tubes is preferably 100 to 150 mm. When the sum of the lengths is less than 100 mm, the effect of irregularities is insufficient and uniform coagulation is not achieved. For example, if the length exceeds 150 mm, the pumping ability of the coagulation solution stored in the coagulation bath It can fall.

The injection port is attached to one side of the first solidification tube, preferably at an angle of 20 to 40 degrees, preferably at an angle of 30 degrees. If it is attached outside the above-mentioned angle, that is, 20 to 40 degrees, the pumping ability to the coagulating solution becomes too slow, and high-speed spinning becomes impossible.

The secondary coagulation solution injected through the injection port is manufactured so that the composition and temperature of the primary coagulation solution and the solvent are different. This is also intended to promote the generation of turbulence as in the case of the second coagulation tube of concavo-convex shape.

The promotion of the generation of the turbulent flow can improve the extraction of the residual solvent, particularly sulfuric acid, and prevent the deterioration of the properties of the finally produced aramid fiber.

The properties of the aramid fiber may include elongation and tensile strength. Needless to say, however, the present invention is not limited thereto and includes all physical properties that can be measured by a person skilled in the art.

Hereinafter, the present invention will be described in more detail with reference to examples and comparative examples. It should be noted, however, that the scope of the present invention should not be limited by the following examples.

[Example 1]

The spinning solution was prepared by dissolving polyparaphenylene terephthalamide (PPTA) in 100% sulfuric acid using the apparatus shown in Fig. The concentration of polyparaphenylene terephthalamide (PPTA) in the spinning solution was adjusted to be 19.5 wt%. The spinning solution was extruded through a spinneret by dry-jet wet spinning and then solidified while passing through an air layer, a first coagulation bath, an injection nozzle and a second coagulation tube, and sulfuric acid used as a solvent The aramid filaments were formed by extraction.

The injection port is attached to the lower end of the first coagulation tube at an angle of 30 DEG to the fiber advancing direction and the inner diameter is 10 mm. The second solidification tube has a cross-sectional area of 8 to 11 mm in diameter, a concave-convex radius of 1.5 mm, and a total solidification tube length of 150 mm.

The temperature of the coagulating solution was maintained at 3 캜, and the concentration of sulfuric acid in the coagulating solution was 9% by weight.

1500 denier aramid fibers were spun at a speed of 700 m / m through the above production apparatus.

[Example 2]

The aramid fiber was prepared in the same manner as in Comparative Example 1, except that the temperature for spraying the secondary coagulation solution through the injection port was maintained at 35 캜.

[Example 3]

The aramid fiber was prepared in the same manner as in Comparative Example 1, except that the concentration of sulfuric acid was maintained at 2% by weight during the injection of the secondary coagulation solution through the injection port.

[Example 4]

The aramid fiber was prepared in the same manner as in Example 1, except that the temperature during spraying of the secondary coagulation solution through the injection port was maintained at 35 ° C and the concentration of sulfuric acid in the coagulation solution was maintained at 2% by weight.

[Comparative Example 1]

An aramid fiber was produced in the same manner as in Example 1, except that the cross-sectional shape of the second coagulation tube was circular and the concentration of sulfuric acid was 9 wt% and the temperature was kept at 3 캜 during the injection of the secondary coagulating solution .

[Evaluation of physical properties]

The prepared aramid fibers were cut to a length of 25 cm to prepare a sample, and then tensile strength and elongation were measured according to the ASTM D-885 test method.

Specifically, the strength (g) when each sample was broken at a tensile speed of 300 mm / min was measured using an Instron Engineering Corp (Canton, Mass), and the measured value was measured as a denier And the tensile strength (g / d) was obtained. Further, the elongation length at the time of breaking the sample was measured, and the elongation (%) was obtained by dividing the measured value by the initial length (25 cm) of the sample.

The experimental results are shown in Table 1.

division Example 1 Example 2 Example 3 Example 4 Comparative Example 1 Tensile strength (g / d) 25.3 23.2 23.5 26.1 18.5 Shinto (%) 3.46 3.22 3.17 3.58 2.59 Salt content (ppm) 3512 2156 2736 1735 3524

It can be seen from Table 1 that the aramid fibers produced by the manufacturing apparatus and method of the present invention have superior tensile strength and elongation and lower sulfate content than Comparative Example 1 produced by the conventional production method. This is due to the fact that the production process of the present invention is caused by turbulence and improved extraction of sulfuric acid as a solvent.

The terminology used in this application is used only to describe a specific embodiment and is not intended to limit the invention.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms such as those defined in commonly used dictionaries are to be interpreted as having a meaning consistent with the contextual meaning of the related art and are to be interpreted as either ideal or overly formal in the sense of the present application Do not.

110: Dope supply unit 120:
130: solidification unit 131: solidification tank
132: first solidification tube 133: second solidification tube, nozzle

Claims (5)

In an apparatus for producing an aramid fiber,
The device
A dope supply unit for supplying dope;
A spinneret for extruding the dope supplied from the dope supply unit;
A solidifying portion for solidifying the dope extruded from the spinneret; Configured
Wherein the solidifying portion comprises:
A coagulation bath located below the spinneret and containing a coagulating solution;
A first coagulation tube positioned below the coagulation bath to provide a discharge passage for the coagulation liquid;
An injection port attached to one side of the first coagulation tube at an angle of 20 to 40 degrees to inject a second coagulating solution;
A second solidification tube attached to a lower end portion of the injection port; Respectively,
Wherein the second solidification tube has a concavo-convex shape.
The method according to claim 1,
Wherein the second solidification tube has a cross-sectional area of 8 to 11 mm in diameter and a concavo-convex radius of 0.5 to 1.5 mm.
The method according to any one of claims 1 to 3,
Wherein the sum of the lengths of the first and second coagulation tubes is 150 mm.
The method of claim 3,
Wherein the secondary coagulating solution injected through the injection port has a different composition and temperature from the primary coagulating solution and the solvent.
An aramid fiber produced by the apparatus of any one of claims 1 to 4

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