KR20160072030A - Method of manufacturing copolymerized aramid fiber and copolymerized aramid fiber manufactured thereby - Google Patents

Abstract

The present invention relates to manufacture of copolymerized aramid fiber. Graphene, graphene oxide, or a mixture thereof is added to an organic solvent. Then, aromatic diamine is injected and dissolution is performed so that an organic solvent in which the aromatic diamine is dissolved is produced. Terephthaloyl dichloride addition and reaction are performed in the organic solvent in which the aromatic diamine is dissolved so that a polymer solution containing an aramid copolymer is produced. The copolymerized aramid fiber is produced by spinning, coagulation, and heat treatment being performed for the polymer solution. Since the graphene that is highly compatible with the aramid copolymer and has crystallinity is added before the injection and dissolution of the aromatic diamine in the organic solvent, rapid increase in polymer solution viscosity can be prevented. The graphene can be dispersed well in the organic solvent, and dispersibility is improved based on interaction between the graphene and the aramid copolymer during an aramid copolymer polymerization process, and thus agglomeration over time can be effectively prevented. Hence, the copolymerized aramid fiber manufactured by the method has significantly improved strength with fiber defect minimized. Furthermore, spinning can be improved since the graphene injected into the organic solvent affects the crystallinity of the aramid copolymer and reduces the elasticity of the polymer solution.

Description

TECHNICAL FIELD The present invention relates to a method for producing a copolymerized aramid fiber and a copolymerized aramid fiber produced by the method.

The present invention relates to a method for producing a copolymerized aramid fiber and a copolymerized aramid fiber produced by the method. More specifically, the present invention relates to a graft copolymer having excellent compatibility with an aramid copolymer and a liquid crystalline graphene, a graphene oxide or a mixture thereof Quot;) is uniformly dispersed in the fibers, and the strength is greatly improved. The present invention also relates to a copolymerized aramid fiber produced by the method.

Aromatic polyamides, commonly referred to as aramids, include para-aramids having a structure in which benzene rings are linearly connected through an amide group (CONH), and meta-based aramids that are not.

Para-aramid has excellent properties such as high strength, high elasticity and low shrinkage. The thin thread of 5 mm thickness produced from this has a strength enough to lift a 2-tonne automobile, so it is used not only for bulletproof but also for various applications in the aerospace industry.

In addition, since aramid is carbonized black at a temperature of 500 ° C or higher, it is also in the spotlight where high heat resistance is required.

A method of producing an aramid fiber is well described in Korean Patent Registration No. 10-0910537 of the present applicant. According to this patent, an aromatic diamine is dissolved in a polymerization solvent to prepare a mixed solution, and an aromatic diacid is added to this to prepare an aramid polymer. The aramid fiber is finally completed by dissolving the aramid polymer in a sulfuric acid solvent to prepare a spinning dope, spinning the spinning dope, followed by coagulation, washing, and drying.

However, when the aramid fiber is produced through such a process, since a solid state aramid polymer is prepared and then dissolved again in a sulfuric acid solvent to prepare a spinning dope, the spinning process is complicated and harmful to the human body, And the durability is degraded due to corrosion.

Furthermore, since the sulfuric acid solvent used to dissolve the aramid polymer having high chemical resistance and removed after the spinning causes environmental pollution, it has to be appropriately treated after use. The cost for treating such spent sulfuric acid is not only economical .

In order to solve the above problem, Korean Patent No. 10-171994 discloses a method for producing an aramid fiber without using a sulfuric acid solvent by directly irradiating a copolymerized aramid polymerization solution with an emissivity pro- cess, .

Specifically, in the above prior art, terephthaloyl dichloride is added to an organic solvent in which paraphenylenediamine and cyano-para-phenylenediamine are dissolved and reacted to polymerize the polymerization solution containing the aramid copolymer, The solution was spun and coagulated to produce copolymerized aramid fibers.

However, the above-mentioned prior art has an advantage of not using a sulfuric acid solvent. However, since the polymer solution used as a spinning agent has a high elasticity, a spinning phenomenon occurs immediately below the spinneret during fiber spinning, There are problems in that the fiber strength is lowered due to many defects in the fiber.

On the other hand, in Korean Patent Laid-Open Publication No. 10-2014-0131710, when a polymerization solvent containing an aramid copolymer is prepared by adding terephthaloyl dichloride to a container solvent in which an aromatic diamine is dissolved and reacting, terephthaloyl dichloride and The present invention also relates to a method for producing a composite aramid fiber which improves radioactivity and improves fiber strength by preventing the phenomenon of die swelling under the condition of spinning when the polymerization solvent is spinned in a fiber form by lowering the elasticity of the polymerization solvent, And a method for producing the same.

However, in the case of Korean Patent Laid-Open No. 10-2014-0131710, since graphene is added together with terephthaloyl dichloride to an organic solvent in which an aromatic diamine is dissolved, the viscosity of the polymerization solvent increases sharply, And the grains tend to aggregate with time, which leads to an increase in the defects in the radiated fibers, thereby limiting the strength of the fibers.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention It is an object of the present invention to provide a method for producing a copolymerized aramid fiber by using a polymerization solution containing an aramid copolymer, The present invention provides a method for producing a copolymerized aramid fiber capable of minimizing defects in the copolymerized aramid fiber and improving the fiber strength by improving the dispersibility of graphene added to the polymerization solution.

In order to accomplish the above object, the present invention provides a method for producing an organic solvent in which an aromatic diamine is dissolved by adding an aromatic diamine to an organic solvent after first adding graphene, graphene oxide, or a mixture thereof, Then, terephthaloyl dichloride is added and reacted with an organic solvent in which the aromatic diamine is dissolved to prepare a polymerization solution containing an aramid copolymer. Then, the polymerization solution is radiated, coagulated and heat-treated in succession to prepare a copolymerized aramid fiber .

Since graphene, which is excellent in compatibility with an aramid copolymer and has liquid crystallinity, is added before an aromatic diamine is added and dissolved in an organic solvent, an additive such as graphene in the polymerization process of an aramid copolymer Aramid copolymer to improve the dispersibility and effectively prevent agglomeration over time, so that the copolymerized aramid fiber prepared according to the present invention minimizes defects in the fiber and greatly improves the strength.

Specifically, the graphene added to the organic solvent before the aromatic diamine is easily dispersed in the organic solvent, and when the polymerization of the aramid copolymer occurs in the state where the graphene is dispersed in the organic solvent, the graphene The aggregation is effectively inhibited, and the dispersibility of the graphene in the polymerization solvent or in the aramid copolymer is improved.

In addition, the present invention reduces the elasticity of the polymerization solution because the graphene added to the organic solvent affects the liquid crystallinity of the aramid copolymer, so that the radioactivity also improves.

Hereinafter, the present invention will be described in detail.

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 invention. It will be apparent to those skilled in the art that variations are possible. Therefore, the present invention encompasses all changes and modifications that come within the scope of the invention as defined in the appended claims and equivalents thereof.

In the present invention, first, graphene, graphene oxide, or a mixture thereof (hereinafter abbreviated as "graphene") is added and dispersed in an organic solvent.

The amount of graphene added in the organic solvent is preferably 0.001 to 1 wt%, more preferably 0.001 to 1 wt%, based on the weight of the aramid copolymer obtained after the polymerization. If the amount of graphene is less than 0.001 wt% , The dispersibility may be lowered.

Graphene added to the organic solvent before the aromatic diamine is easily dispersed in the organic solvent medium. When the polymerization of the aramid copolymer occurs in the state where the graphene is dispersed in the organic solvent, aggregation of the graphene particles with time So that the dispersibility of the graphene in the polymerization solvent or in the aramid copolymer is improved.

The graphene is a material having a two-dimensional planar structure in which carbon atoms are connected in a honeycomb-like hexagonal shape, and includes not only pure graphene but also graphene oxide.

The graphene is excellent in compatibility with the copolymerized aramid polymer, and the liquid crystallinity of the graphene affects the liquid crystallinity of the copolymerized aramid copolymer, thereby reducing the elasticity of the spinning dope as the polymerization solution. As a result, the present invention prevents the phenomenon of die swelling in the lower part of the crotch, thereby greatly improving radioactivity.

Next, an inorganic salt is dissolved in an organic solvent to which graphene is added, and then an aromatic diamine is added to dissolve the inorganic salt.

At this time, paraphenylenediamine and cyano-para-phenylenediamine may be dissolved in a molar ratio of 1: 9 to 9: 1 as the aromatic diamine, or cyano-para-phenylenediamine may be solely dissolved.

Specific examples of the organic solvent include N-methyl-2-pyrrolidone (NMP), N, N-dimethylacetamide (DMAc), hexamethylphosphoramide (HMPA) Tetramethylurea (TMU), N, N-dimethylformamide (DMF), or mixtures thereof.

The inorganic salt is added in order to increase the degree of polymerization of the aromatic polyamide. Specific examples thereof include alkali metal halides such as CaCl ₂ , LiCl, NaCl, KCl, LiBr and KBr, or alkaline earth metal halides. These inorganic salts may be added singly or in the form of a mixture of two or more.

The addition amount of the inorganic salt is preferably about 2 to 5% by weight based on the weight of the organic solvent.

Next, terephthaloyl dichloride is added to the organic solvent in which paraphenylenediamine and cyano-para-phenylenediamine (hereinafter referred to as "diamine component") are added and dissolved in the same molar amount as the diamine component Molar amount, and graphene is also added to the organic solvent to prepare a polymerization solvent containing the copolymerized aramid polymer.

Next, the polymerized solution prepared as described above is extruded through a spinneret as it is, and the extruded polymer solution is coagulated as a coagulating solution and then heat-treated to produce co-fibrillated aramid fibers on the filament.

The copolymerized aramid fiber produced by the method according to the present invention contains graphene in the fiber and has a strength of 30 to 35 g / d.

The content of graphene contained in the fibers is 0.001 to 1% by weight based on the weight of the fibers.

Hereinafter, the present invention will be described in more detail with reference to examples and comparative examples.

Example 1

An organic solvent of N-methyl-2-pyrrolidone was placed in a reactor under nitrogen atmosphere, and 0.1 wt% of graphene (based on the weight of the copolymer) was added and dispersed in the organic solvent to obtain an organic solvent in which graphene was dispersed.

Next, 3 wt% of CaCl ₂ (based on the weight of the organic solvent) was added to and dissolved in the organic solvent in which graphene was dispersed, and then 50 mol% of p-phenylenediamine and 10 wt% 50 mol% of cyano-p-phenylenediamine was dissolved in the reactor to prepare a mixed solution.

Then, 100 mol% of terephthaloyl dichloride was added to the reactor containing the mixed solution to prepare a polymerization solution containing an aramid copolymer.

Then, the polymer solution was extruded through a spinneret, and then passed through an air gap and a coagulating liquid sequentially to form a multifilament having a linear density of 3,000 deniers. The pressure in the spinning pack was 2,800 psi and the spinning speed was 600 mpm (meter per minuite).

Subsequently, the multifilament was washed with water, and the washed multifilament was dried and stretched by a drying roller set at a temperature of 150 ° C. The drawn multifilament was heat-treated at 250 ° C and wound up to produce a copolymerized aramid fiber.

Table 1 shows the results of evaluating the strength and radioactivity of the copolymerized aramid fibers.

Example 2

An organic solvent of N-methyl-2-pyrrolidone was placed in a reactor under a nitrogen atmosphere, and 0.5 wt% of graphene (based on the weight of the copolymer) was added and dispersed in the organic solvent to obtain an organic solvent in which graphene was dispersed.

Next, 3 wt% of CaCl ₂ (based on the weight of the organic solvent) was added to and dissolved in the organic solvent in which graphene was dispersed, and then 50 mol% of p-phenylenediamine and 10 wt% 50 mol% of cyano-p-phenylenediamine was dissolved in the reactor to prepare a mixed solution.

Then, 100 mol% of terephthaloyl dichloride was added to the reactor containing the mixed solution to prepare a polymerization solution containing an aramid copolymer.

Then, the polymer solution was extruded through a spinneret, and then passed through an air gap and a coagulating liquid sequentially to form a multifilament having a linear density of 3,000 deniers. The pressure in the spinning pack was 2,800 psi and the spinning speed was 600 mpm (meter per minuite).

Subsequently, the multifilament was washed with water, and the washed multifilament was dried and stretched by a drying roller set at a temperature of 150 ° C. The drawn multifilament was heat-treated at 250 ° C and wound up to produce a copolymerized aramid fiber.

Table 1 shows the results of evaluating the strength and radioactivity of the copolymerized aramid fibers.

Example 3

N-methyl-2-pyrrolidone organic solvent was placed in a reactor under nitrogen atmosphere, and 0.7 wt% of graphene (based on the weight of the copolymer) was added to and dispersed in the organic solvent to obtain an organic solvent in which graphene was dispersed.

Next, 3 wt% of CaCl ₂ (based on the weight of the organic solvent) was added to and dissolved in the organic solvent in which graphene was dispersed, and then 50 mol% of p-phenylenediamine and 10 wt% 50 mol% of cyano-p-phenylenediamine was dissolved in the reactor to prepare a mixed solution.

Then, 100 mol% of terephthaloyl dichloride was added to the reactor containing the mixed solution to prepare a polymerization solution containing an aramid copolymer.

Then, the polymer solution was extruded through a spinneret, and then passed through an air gap and a coagulating liquid sequentially to form a multifilament having a linear density of 3,000 deniers. The pressure in the spinning pack was 2,800 psi and the spinning speed was 600 mpm (meter per minuite).

Subsequently, the multifilament was washed with water, and the washed multifilament was dried and stretched by a drying roller set at a temperature of 150 ° C. The drawn multifilament was heat-treated at 250 ° C and wound up to produce a copolymerized aramid fiber.

Table 1 shows the results of evaluating the strength and radioactivity of the copolymerized aramid fibers.

Example 4

An organic solvent of N-methyl-2-pyrrolidone was placed in a reactor under a nitrogen atmosphere, and 1 wt% of graphene (based on the weight of the copolymer) was added and dispersed in the organic solvent to obtain an organic solvent in which graphene was dispersed.

Next, 3 wt% of CaCl ₂ (based on the weight of the organic solvent) was added to and dissolved in the organic solvent having the graphene dispersed therein, and 100 mol% of cyano-p-phenylenediamine The mixture was put into the reactor and dissolved to prepare a mixed solution.

Then, 100 mol% of terephthaloyl dichloride was added to the reactor containing the mixed solution to prepare a polymerization solution containing an aramid copolymer.

Then, the polymer solution was extruded through a spinneret, and then passed through an air gap and a coagulating liquid sequentially to form a multifilament having a linear density of 3,000 deniers. The pressure in the spinning pack was 2,800 psi and the spinning speed was 600 mpm (meter per minuite).

Subsequently, the multifilament was washed with water, and the washed multifilament was dried and stretched by a drying roller set at a temperature of 150 ° C. The drawn multifilament was heat-treated at 250 ° C and wound up to produce a copolymerized aramid fiber.

Table 1 shows the results of evaluating the strength and radioactivity of the copolymerized aramid fibers.

Comparative Example 1

An N-methyl-2-pyrrolidone (NMP) organic solvent containing 3% by weight of CaCl ₂ was placed in a reactor under a nitrogen atmosphere, and 50 mol% of para-phenylenediamine and 40% 50 mol% of cyano-p-phenylenediamine was dissolved in the reactor to prepare a mixed solution.

Then, 100 mol% of terephthaloyl dichloride was added to the reactor containing the mixed solution to prepare a polymerization solution containing the copolymerized aramid polymer.

At this time, graphene was not added to the polymerization solution.

Then, the polymer solution was extruded through a spinneret, and then passed through an air gap and a coagulating liquid sequentially to form a multifilament having a linear density of 3,000 deniers. The pressure in the spinning pack was 2,800 psi and the spinning speed was 600 mpm (meter per minuite).

Subsequently, the multifilament was washed with water, and the washed multifilament was dried and stretched by a drying roller set at a temperature of 150 ° C. The drawn multifilament was heat-treated at 250 ° C and wound up to produce a copolymerized aramid fiber.

Table 1 shows the results of evaluating the strength and radioactivity of the copolymerized aramid fibers.

Comparative Example 2

An N-methyl-2-pyrrolidone (NMP) organic solvent containing 3% by weight of CaCl ₂ was placed in a reactor under a nitrogen atmosphere, and 50 mol% of para-phenylenediamine and 40% 50 mol% of cyano-p-phenylenediamine was dissolved in the reactor to prepare a mixed solution.

Then, 100 mol% of terephthaloyl dichloride and 0.5 wt% of graphene (based on the weight of the copolymer) were simultaneously added to the reactor containing the mixed solution to prepare a polymerization solution containing the copolymerized aramid polymer.

Subsequently, the polymer solution was extruded through a spinneret, and then passed through an air gap and a coagulating liquid sequentially to form a multifilament having a linear density of 3,000 denier. The pressure in the spinning pack was 2,800 psi and the spinning speed was 600 mpm (meter per minuite).

Subsequently, the multifilament was washed with water, and the washed multifilament was dried and stretched by a drying roller set at a temperature of 150 ° C. The drawn multifilament was heat-treated at 250 ° C and wound up to produce a copolymerized aramid fiber.

Table 1 shows the results of evaluating the strength and radioactivity of the copolymerized aramid fibers.

division Strength (g / d) Radioactive Example 1 30 Great Example 2 32 Great Example 3 33 Great Example 4 35 Great Comparative Example 1 25 Bad Comparative Example 2 29 usually

The strength and radioactivity of the above Table 1 were evaluated in the following manner.

Strength of aramid fiber (g / d)

The strength of the aramid fiber was determined by measuring the strength at the breaking point after stretching until a sample of 25 cm in length was broken in an Instron tester (Instron Engineering Corp, Canton, Mass) according to ASTM D885, Was tested five or more times and then the average value was obtained. At this time, the tensile speed was 300 mm / min, and the initial load was 1 × 30 g of fineness.

Radioactive

The die swelling phenomenon immediately below the spinneret was visually observed and evaluated. Specifically, when the swelling phenomenon was observed immediately after observation, it was determined to be "poor ". When the swelling phenomenon was confirmed only after close observation, it was determined to be" normal ". If the swelling phenomenon "Excellent ".

Claims (7)

(I) adding and dispersing one kind of graphene, graphene oxide, and a mixture of graphene and graphene oxide to an organic solvent;
(Ii) introducing and dissolving aromatic diimine into an organic solvent in which one kind of graphene, graphene oxide, and a mixture of graphene and graphene oxide is dispersed to prepare an organic solvent in which the aromatic diamine is dissolved;
(Iii) adding terephthaloyl dichloride to the organic solvent in which the aromatic diamine is dissolved and reacting to prepare a polymerization solution containing an aramid copolymer;
(Iv) a step of spinning, coagulating and heat-treating the polymerization solution containing the aramid copolymer to prepare a co-aramid fiber. The aramid fiber according to claim 1, wherein the content of graphene, graphene oxide, and a mixture of graphene and graphene oxide in an organic solvent is 0.001 to 1 wt% based on the weight of the aramid copolymer ≪ / RTI > The method for producing a co-aramid fiber according to claim 1, wherein the organic solvent is dissolved in an aromatic diamine at a molar ratio of 1: 9 to 9: 1 with paraphenylenediamine and cyano-para-phenylenediamine. The method for producing a co-aramid fiber according to claim 1, wherein cyano-para-phenylenediamine is solely dissolved in the organic solvent as an aromatic diamine. The method for producing a co-aramid fiber according to claim 1, wherein terephthaloyl dichloride is added to the organic solvent in which the aromatic diamine is dissolved in the same molar amount as the entire aromatic diamine dissolved in the organic solvent. A co-aramid fiber prepared by the method of claim 1, characterized in that the fiber contains graphene, graphene oxide and one selected from graphene and graphene oxide and has a strength of 30 to 35 g / d The co-aramid fiber according to claim 5, wherein the content of one of graphene, graphene oxide and graphene in the fiber is 0.001 to 1 wt% based on the weight of the fiber.