KR101881827B1 - Apparatus For Producing Aramid Fibers Composed Of Multi-stage Coagulation Baths And Aramid Fibers - Google Patents

Abstract

The present invention provides a dope supply apparatus comprising: a dope supply unit for supplying dope; A spinneret for extruding the dope supplied from the dope supply unit; And a solidifying portion composed of a multi-stage solidifying tank for solidifying the dope extruded from the spinneret, wherein the solidifying portion is located at a lower portion of the spinneret and contains a primary solidifying liquid; A first inlet for providing a primary coagulation solution on the side of the primary coagulation bath; A first coagulation tube positioned below the primary coagulation bath to provide a discharge passage for the primary coagulation liquid; A second coagulation tank connected to the lower portion of the first coagulation tank; a second inlet for providing a second coagulation solution on the side of the second coagulation tank; And a second coagulation tube positioned below the second coagulation bath to provide a discharge passage for the second coagulating solution, wherein the dope extruded from the spinneret is supplied to the first coagulation bath, the first coagulation bath, The coagulation bath, and the second coagulation tube in this order, thereby forming a multifilament. The present invention relates to an apparatus for producing an aramid fiber composed of a multistage coagulation bath.

Description

[0001] The present invention relates to an apparatus for producing an aramid fiber composed of a multi-stage coagulating bath and an aramid fiber produced by the same.

The present invention relates to an apparatus for producing aramid fibers and an aramid fiber produced therefrom. In order to improve the efficiency of the conventional wet spinning, a vertical temperature gradient of a multi-stage coagulation bath is used to maximize the removal of residual mixed solvent in the dope, And an aramid fiber produced 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. 2013-0075216 discloses 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.

Korean Patent Laid-Open Publication No. 2016-0071713 has a concavo-convex shape instead of a plurality of grooves extending in a direction parallel to the longitudinal direction of the coagulation tube.

The grooves, concavo-convex shapes and the like of the coagulation tube have the feature of suppressing the occurrence of turbulent flow in the secondary injection of the solid solution at one side of the coagulation tube.

Accordingly, the present invention has developed a device capable of improving the strength and elongation of the radiation source by controlling the flow rate and temperature of the first and second coagulating liquids instead of the turbulence suppressing device of the coagulating tube.

It is an object of the present invention to solve the above-mentioned problems by providing a method and apparatus for separating a filament from a filament by using a multi-stage coagulation bath in the process of solidifying the dope extruded through a detergent, And an apparatus for producing an aramid fiber capable of minimizing the amount of salt remaining in the fiber.

Another object of the present invention is to provide an apparatus for producing an aramid fiber capable of minimizing the amount of salt remaining in the aramid fiber due to the difference in the flow rate of the coagulating solution injected into the vertical coagulation tank.

In order to solve the above problems, the present invention provides a dope supply apparatus comprising: a dope supply unit for supplying dope; A spinneret for extruding the dope supplied from the dope supply unit; And a solidifying portion composed of a multi-stage solidifying tank for solidifying the dope extruded from the spinneret, wherein the solidifying portion is located at a lower portion of the spinneret and contains a primary solidifying liquid; A first inlet for providing a primary coagulation solution on the side of the primary coagulation bath; A first coagulation tube positioned below the primary coagulation bath to provide a discharge passage for the primary coagulation liquid; A second coagulation tank connected to the lower portion of the first coagulation tank; a second inlet for providing a second coagulation solution on the side of the second coagulation tank; And a second coagulation tube positioned below the second coagulation bath to provide a discharge passage for the second coagulating solution, wherein the dope extruded from the spinneret is supplied to the first coagulation bath, the first coagulation bath, The coagulation bath, and the second coagulation tube in this order, thereby forming a multifilament. The present invention also provides an apparatus for producing an aramid fiber comprising the multistage coagulation bath.

Further, the present invention is characterized in that the first flow rate (P) of the first coagulation liquid supplied to the first inlet and the second flow rate (Q) of the second coagulation liquid supplied to the second inlet are expressed by the following equations (2), wherein the first flow rate (P) is larger than the second flow rate (Q). The present invention also provides an apparatus for producing an aramid fiber.

The first flow rate (P) = (De ^ 0.25) / (8 * (Mono-De)

Second flow rate Q = first flow rate P / ((Mono-De) ^ 1.5) (2)

The unit of flow rate is m ³ / h,

De is the fineness of the multifilament aramid fiber,

Mono-De is the monofilament fineness constituting the multifilament.

The present invention also provides an apparatus for producing an aramid fiber comprising a multistage coagulation bath characterized in that the dope extruded from the spinneret is extruded in a primary coagulating solution.

Also, the present invention provides an apparatus for producing an aramid fiber comprising a multi-stage coagulating bath characterized in that the temperature of the primary coagulating liquid is 70 to 90 ° C and the temperature of the secondary coagulating liquid is 3 to 20 ° C.

The present invention also provides aramid fibers produced by the apparatus described above.

Also, the present invention provides a multifilament aramid fiber characterized in that the fineness of the aramid fiber is 600 to 30,000 Da.

The present invention facilitates the extraction of the solvent, especially sulfuric acid, in the filament due to the temperature gradient by using a multi-stage coagulation bath in the process of solidification of the dope extruded through coagulation by the coagulating solution, thereby minimizing the salt content remaining in the aramid fiber There is an effect that can be done.

In addition, the present invention has the effect of minimizing the amount of salt remaining in the aramid fiber due to the difference in the flow rate of the coagulating solution injected into the vertical coagulation tank.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic view showing features of an apparatus for producing aramid fibers constituted by a multi-stage coagulating bath of the present invention. Fig.

Hereinafter, preferred embodiments of the present invention will be described in detail. In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted so as to avoid obscuring the subject matter of the present invention.

As used herein, the terms " about, " " substantially, " " etc. ", when used to refer to a manufacturing or material tolerance inherent in the stated sense, Accurate or absolute numbers are used to help prevent unauthorized exploitation by unauthorized intruders of the referenced disclosure.

Among aramid fibers, para-aramid is a type of aromatic polyamide having high strength and high modulus of elasticity, and has excellent properties such as polyparaphenylene terephthalamide (PPD-T), poly (4,4'-benzanilide terephthalamide) Phenylene-4,4'-biphenylene-dicarboxylic acid amide), poly (paraphenylene-2,6-naphthalene dicarboxylic acid amide), or a mixture of two or more thereof.

The para-aramid may be prepared 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.

Then, through the dehydration and drying processes, the water remaining in the para-aramid can be removed.

The present invention relates to an apparatus for producing a para-aramid fiber for efficiently removing a polymerization solvent from the polymerization solution using a multistage coagulation bath.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic view showing features of an apparatus for producing aramid fibers constituted by a multi-stage coagulating bath of the present invention. Fig. As shown in the figure, the present invention provides a dope supply apparatus comprising: a dope supply unit 110 for supplying dope; A spinneret 120 for extruding the dope supplied from the dope supply unit; And a solidifying portion composed of a multi-stage solidifying tank for solidifying the dope extruded from the spinneret 120.

A feature of the present invention is that the solidification portion is composed of multiple stages and the dope extruded from the spinneret 120 is solidified while releasing the polymerization solvent from the dope in turn through the primary coagulating solution 135 and the secondary coagulating solution 145 The multifilament 150 is formed.

A first coagulation bath 130 located below the spinneret 120 and containing a first coagulating solution 135; A first inlet 131 for providing a primary coagulation solution 135 to the primary coagulation bath 130; A first coagulation tube 133 located below the primary coagulation bath 130 to provide a discharge passage for the primary coagulation liquid 135; A secondary coagulation bath (140) connected to a lower portion of the primary coagulation bath (130) and containing a secondary coagulating liquid (145); A second inlet (141) for providing a second coagulation liquid (145) to the second coagulation bath (140); And a second coagulation tube 143 positioned below the secondary coagulation bath 140 to provide a discharge passage for the secondary coagulation liquid 145.

The prepared para-aramid dope is supplied to the spinneret 120 through the dope supplying section 110 and then extruded. The spinneret 120 has a plurality of capillaries having a diameter of 0.1 mm or less. If the diameter of the capillary formed in the spinneret 120 exceeds 0.1 mm, the molecular orientation of the produced monofilament is deteriorated, which results in lowering the strength of the multifilament.

The dope extruded into the spinneret 120 is extruded in the primary coagulating solution. The reason why the extruded dope is extruded from the primary coagulation solution immediately without an air gap exposed to an inert gas is that the surface drying and deformation of the dope may occur due to the temperature and humidity of the exposed gas.

The primary coagulating solution 135 is supplied at a constant flow rate from the first inlet 131 located on the side of the primary coagulation bath 130. The supplied primary coagulating solution 135 is discharged together with the extruded dope to the first coagulation tube 133 located under the primary coagulating bath 130. The primary coagulating solution 135 is supplied to the first coagulation bath 130 by adjusting the supplied flow rate and the flow rate of the first coagulation tube 133, .

The primary coagulation solution 135 flowing out to the first coagulation tube 133 and the extruded dope are introduced into the secondary coagulation bath 140 connected to the lower part of the primary coagulation bath 130. The volume of the secondary coagulation bath 140 is larger than the volume of the primary coagulation bath 130 and the second inlet 141 is located on the side of the secondary coagulation bath 140 to provide the secondary coagulating solution 145 The second coagulating solution 145 is also discharged to the outside through the second coagulating tube 143 located under the second coagulating bath 140.

The first coagulation tube 133 and the second coagulation tube 143 are positioned on a vertical line and are arranged in the moving space of the dope extruded from the spinneret 120 and the primary coagulating solution 135 and the secondary coagulating solution 145 .

Also, the temperature of the primary coagulating solution 135 is 70 to 90 ° C, and the temperature of the secondary coagulating solution 145 is 3 to 20 ° C.

As described above, the temperature difference of the first and second coagulating liquids 135 and 145 is maintained because the temperature of the dope supplied to the dope supplying unit is usually maintained at 120 to 150 ° C. in order to secure the viscosity for radiation. The dope extruded from the spinneret 120 is to be extracted from the polymerization solution of the dope in the primary coagulation solution. The temperature of the primary coagulation solution at 70 to 90 ° C is the temperature at which the surface of the dope is cracked or doped The shape deformation can be prevented and the extraction process of the polymerization solvent for the primary coagulation solution of 70 to 90 ° C can be facilitated.

Also, the temperature of the secondary coagulating solution (145) is 3 to 20 占 폚. Since the temperature of 3 to 20 ° C is the temperature at the side of the secondary coagulation bath 140, the temperature of the vicinity of the second coagulation tube is the temperature of the primary coagulation bath 135 of 70 to 90 ° C, Some can be mixed and can have slightly higher values.

This is because the aramid filaments can be adjusted to a temperature similar to the operating temperature and the polymerization solvent can be further extracted to firmly fix the relaxed state of the dope at 70 to 90 ° C and extract the remaining polymerization solvent in the fixed state, The para-aramid multifilament solidified without any change in surface and shape can be obtained.

The first flow rate P of the primary coagulation liquid 135 provided to the first inlet 131 and the secondary flow rate Q of the secondary coagulation liquid 145 provided to the second inlet 141 are set to be the same, Can be specified by the following equations (1) and (2).

The first flow rate (P) = (De ^ 0.25) / (8 * (Mono-De)

Second flow rate Q = first flow rate P / ((Mono-De) ^ 1.5) (2)

The first flow rate P has a value larger than the second flow rate Q. 1, the volume of the second coagulation bath 140 is larger than the volume of the first coagulation bath 130 and the volume of the second coagulation bath 130 is smaller than the first coagulation tube diameter d1. 2 The solidification tube diameter (d2) is large. In this case, the second coagulating solution 145 flowing into the second coagulating bath 140 through the second inlet 141 and the first coagulating solution moving from the first coagulating tube 133 to the second coagulating bath 140 145 is equal to the amount of outflow of the second coagulation tube 143, so that the height of the water surface of the first and second coagulation baths can be made constant.

Hereinafter, the present invention will be described in more detail with reference to examples. It is to be understood, however, that these examples are provided so as to understand the scope of the present invention, and are not to be construed as limiting the scope of the present invention.

Example  And Comparative Example

Polypara-phenylene terephthalamide (PPD-T) was dissolved in 99% concentrated sulfuric acid to prepare a dope. The concentration of polyparaphenylene terephthalamide (PPD-T) in the dope was adjusted to 20 wt%. The dope was extruded through a spinneret, and then solidified while passing through a coagulation bath and a coagulation tube in order to form a multifilament.

The temperature and flow rate of the primary and secondary coagulating solutions of the examples and comparative examples were the conditions shown in Table 1, and the concentration of sulfuric acid in the coagulating solution was 9% by weight.

Further, the diameter of the second coagulation tube was made larger than the diameter of the first coagulation tube, so that the height of the coagulating solution in the first and second coagulation baths was kept constant.

Aramid  Tensile strength and elongation measurement of fiber

The aramid fibers were cut to 25 cm to prepare a sample, and then the 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 measured value was divided by the initial length (25 cm) of the sample to calculate the elongation percentage (%).

First coagulation amount Second coagulation amount De
Mono
De burglar
(g / d) Elongation rate
(%) Temperature (℃) The first flow rate (P)
(m3 / h) Temperature (℃) The second flow rate (Q)
(m3 / h) Example 1 80 0.34 3 0.18 600 1.5 25.1 12.8 Example 2 75 0.22 8 0.08 600 2.0 24.3 11.9 Example 3 75 0.37 5 0.20 840 1.5 24.6 13.2 Example 4 85 0.38 10 0.21 1000 1.5 24.1 12.2 Example 5 85 0.25 8 0.09 1000 2.0 23.7 11.3 Example 6 75 0.42 10 0.23 1500 1.5 23.9 13.0 Example 7 90 0.90 15 0.49 30000 1.5 22.5 11.8 Comparative Example 1 75 0.30 15 0.1 1000 1.5 15.3 8.2 Comparative Example 2 75 0.51 15 0.32 1000 1.5 16.1 7.9 Comparative Example 3 70 0.38 30 0.2 1000 1.5 - - Comparative Example 4 95 0.38 20 0.2 1000 1.5 - -

As can be seen from Table 1, the values of the above Table 1 regarding the temperature and the flow rate of the primary and secondary coagulating solution of the present invention satisfy the above-mentioned formulas (1) and (2) And the strength and elongation percentage of the comparative example are superior to those of the comparative example.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the inventions. It will be clear to those who have knowledge of.

110: Dope supply unit 120:
130: Primary coagulation bath 131: First inlet
133: first coagulation tube 135: first coagulation liquid
140: Secondary coagulation bath 141: Second inlet
143: second coagulation tube 145: second coagulation liquid
150: Multifilament

Claims (6)

A dope supply unit for supplying dope;
A spinneret for extruding the dope supplied from the dope supply unit; And a solidifying portion composed of a multi-stage solidifying tank for solidifying the dope extruded from the spinneret,
Wherein the solidifying portion is located at a lower portion of the spinneret and contains a primary coagulating solution;
A first inlet for providing a primary coagulation solution on the side of the primary coagulation bath;
A first coagulation tube positioned below the primary coagulation bath to provide a discharge passage for the primary coagulation liquid;
A secondary coagulation bath connected to the lower portion of the primary coagulation bath;
A second inlet for providing a second coagulation solution on the side of the second coagulation bath;
And a second coagulation tube positioned below the second coagulation bath to provide a discharge passage for the second coagulation solution,
Wherein the dope extruded from the spinneret passes through the first coagulation bath, the first coagulation bath, the second coagulation bath and the second coagulation bath in order to form a multifilament,
The first flow rate P of the primary coagulation liquid supplied to the first inlet and the second flow rate Q of the secondary coagulation solution supplied to the second inlet are expressed by the following equations (1) and (2) However,
Wherein the first flow rate (P) is larger than the second flow rate (Q).

The first flow rate (P) = (De ^ 0.25) / (8 * (Mono-De)
Second flow rate Q = first flow rate P / ((Mono-De) ^ 1.5) (2)

The unit of flow rate is m ³ / h,
De is the fineness of the multifilament aramid fiber,
Mono-De is the monofilament fineness constituting the multifilament.
delete The method according to claim 1,
Wherein the dope extruded from the spinneret is extruded in a primary coagulating liquid.
The method according to claim 1,
Wherein the temperature of the primary coagulating liquid is 70 to 90 캜 and the temperature of the secondary coagulating liquid is 3 to 20 캜.
6. An aramid fiber produced by the apparatus of any one of claims 1 to 5.
6. The method of claim 5,
Wherein the aramid fiber has a fineness of 600 to 30,000 Da.

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