KR101570057B1 - Method of manufacturing copolymerized para-aramid fiber - Google Patents

Abstract

The present invention relates to a method for producing a copolymerized para-aramid fiber, which comprises polymerizing a polymerization solution containing a copolymerized aramid polymer by adding terephthaloyl dichloride as an acid component to an organic solvent in which a diamine component is dissolved, In producing the para-aramid fiber by spinning and coagulating the solution, when the polymerization solution is polymerized using cyano-para-phenylenediamine as the diamine component, the cyano-para-phenylenediamine component and the terephthaloyldi Any one of the chloride components is added in excess to the remaining one component and reacted.
The present invention improves solubility degradation due to high intrinsic viscosity by controlling the size of the molecular weight of the polymer by adding an excess of either one of the cyano-para-phenylenediamine component and the terephthaloyl dichloride component during the polymerization process Therefore, it is possible for the present invention to mass-produce the copolymerized para-aramid fiber by directly spinning the polymer solution without using a sulfuric acid solution.

Description

TECHNICAL FIELD The present invention relates to a method for preparing a copolymerized para-aramid fiber,

More specifically, the present invention relates to a method for producing a copolymerized para-aramid fiber by mass-producing a copolymerized aramid fiber without decreasing the strength of the fiber by improving the solubility of the polymer in the polymerization solvent containing the copolymerized polyamide polymer which can be directly radiated without using sulfuric acid It's about how you can.

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 copolymerized aramid polymer, The solution was spun and coagulated to produce copolymerized aramid fibers.

However, in the above-mentioned prior art, since the diamine component composed of paraphenylenediamine and cyano-para-phenylenediamine and the acid component of terephthaloyl dichloride are added and reacted in the same equivalent ratio in the production of the copolymerized aramid, The viscosity (IV) becomes too high, thereby lowering the solubility of the copolymerized aramid polymer in the polymerization solution, and the copolymerized aramid fiber can not be produced in a large amount.

As another conventional technique for improving the solubility of the polymer in the polymerization solution, a method of suitably selecting the kinds of the organic solvent and the inorganic salt has been used.

For example, dimethylacetamide (DMAc) is used as an organic solvent and LiCl is used as an inorganic salt in a large amount. However, the effect of improving the solubility of the polymer is poor and various problems such as radioactivity deterioration due to the use of a large amount of inorganic salts have occurred.

The object of the present invention is to lower the intrinsic viscosity of a polymer to a proper level when producing a copolymerized aramid polymer-containing polymerization solution which is directly used as a radial polymer without the use of sulfuric acid for producing a copolymerized para-aramid fiber, To a method for improving the quality of the image.

In order to achieve the above object, in the present invention, terephthaloyl dichloride is added as an acid component to an organic solvent in which a diamine component is dissolved and reacted to polymerize a polymerization solution containing a copolymerized aramid polymer, , And when the copolymerized para-aramid fiber is produced by solidification, the polymerization solution is polymerized using cyano-para-phenylenediamine as the diamine component, and the cyano-para-phenylenediamine component and the terephthaloyl dichloride component Is added in excess to the remaining one component and reacted to adjust the intrinsic viscosity (IV) of the polymer to be polymerized to an appropriate level.

The present invention improves solubility degradation due to high intrinsic viscosity by controlling the size of the molecular weight of the polymer by adding an excess of either one of the cyano-para-phenylenediamine component and the terephthaloyl dichloride component during the polymerization process Therefore, it is possible for the present invention to mass-produce the copolymerized para-aramid fiber by directly spinning the polymer solution without using a sulfuric acid solution.

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, an inorganic salt is dissolved in an organic solvent, and then a diamine component is added and dissolved.

At this time, paraphenylenediamine and cyano-para-phenylenediamine may be dissolved in a molar ratio of 1: 9 to 9: 1 as a diamine component, 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 as an acid component to the organic solvent to which the diamine component is added and dissolved as described above to prepare a polymerization solvent containing the copolymerized aramid polymer.

The present invention is characterized in that any one of the above-mentioned diamine component and acid component is added in an excess amount over the remaining one component during the polymerization of the polymerization solution and then reacted.

As an embodiment, the acid component can be added in excess by adjusting the equivalent ratio of the diamine component to the acid component to 100: 101-110.

As another embodiment, the diamine component may be reacted in an excess amount by adjusting the ratio of the diamine component to the acid component to 101 to 110: 100.

When the polymerization solution is polymerized, the intrinsic viscosity of the copolymerized aramid polymer can be adjusted to a low level of 3.5 to 5.5 by adding any one of the diamine component and the acid component in excess of the other one component and reacting, The solubility of the copolymerized aramid polymer is greatly improved.

By the improvement of the solubility, the polymer solution can be directly radiated without using sulfuric acid, so that the aramid fiber can be mass-produced without lowering the fiber strength.

Next, the polymerized solution prepared as described above is extruded through a spinneret without using sulfuric acid as it is, and then the extruded polymer solution is solidified as a coagulating solution to prepare filamentary co-aramid fibers.

The strength of the copolymerized aramid fiber produced by the present invention was 23 to 28 g / d, and the intrinsic viscosity (IV) was 3.5 to 5.5.

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

Example  One

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, to the reactor containing the mixed solution, 102 mol% of terephthaloyl dichloride was added 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.

The intrinsic viscosity (IV) of the prepared aramid polymer, the solubility of the aramid polymer in the polymerization solution, and the strength of the copolymerized aramid fiber were measured and the results are shown in Table 2.

Example  2 ~ Example  7 and Comparative Example  One

Copolymerized aramid fibers were prepared in the same manner as in Example 1, except that the addition amounts of paraphenylenediamine, diamino component, cyano-para-phenylenediamine and acid component terephthaloyl dichloride were changed as shown in Table 1 Respectively.

The intrinsic viscosity (IV) of the prepared aramid polymer, the solubility of the aramid polymer in the polymerization solution, and the strength of the copolymerized aramid fiber were measured and the results are shown in Table 2.

Manufacturing conditions division Amount of diamine component added (mol%) Amount of acid added (mol%) Paraphenylenediamine Cyano-para-phenylenediamine Terephthaloyl dichloride Example 1 50 50 102 Example 2 50 50 105 Example 3 50 50 109 Example 4 51 51 100 Example 5 53 52 100 Example 6 54 55 100 Example 7 0 100 100 Comparative Example 1 50 50 100

Evaluation results such as physical properties division Solubility of polymer Intrinsic viscosity (IV) Strength (g / d) Example 1 Great 5.3 27 Example 2 Great 4.2 25 Example 3 Great 3.7 24 Example 4 Great 5.4 27 Example 5 Great 4.4 26 Example 6 Great 3.8 24 Example 7 Great 4.0 25 Comparative Example 1 Bad 6.0 -

Various physical properties of the above Table 2 were evaluated as follows.

Solubility of polymer

The radial dope from which the polymer was dissolved was visually observed to be excellent when there was no gel or solid phase, and was judged to be poor when there was a gel or solid phase.

Aramid  Strength of fiber

The strength of the aramid fiber was determined by measuring the strength at the breaking point after stretching the specimen having a length of 25 in an Instron tester (Instron Engineering Corp, Canton, Mass) according to ASTM D885 until the specimen was broken, After five or more tests, 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.

Measurement of intrinsic viscosity (Inherent Viscosity: I.V.) of para-aramid polymer

The intrinsic viscosity (I.V.) is defined by the following equation.

I.V. = ln (? rel) / C

Where C is the concentration of the polymer solution (solution in which 0.5 g of the polymer is dissolved in 100 ml of concentrated sulfuric acid) and the relative viscosity? Rel is the flow time ratio between the polymer solution and the solvent measured by a capillary viscometer at 30 占 폚. Was measured using a concentrated sulfuric acid solvent of 95 to 98%.

Claims (6)

In the production of the copolymerized para-aramid fiber by polymerizing the polymerization solution containing the copolymerized aramid polymer by adding terephthaloyl dichloride as an acid component to an organic solvent in which the diamine component is dissolved and then radiating and coagulating the polymerization solution ,
When the polymerization solution is polymerized using cyano-para-phenylenediamine as the diamine component, any one of the cyano-para-phenylenediamine component and terephthaloyl dichloride component is added in an excess amount , And reacting the resultant mixture with water. The method according to claim 1, wherein the equivalent ratio of the cyano-para-phenylenediamine component to the terephthaloyl dichloride component is adjusted to 100: 101-110. The method of claim 1, wherein the equivalent ratio of the cyano-para-phenylenediamine component to the terephthaloyl dichloride component is adjusted to 101 to 110: 100. The process for producing a copolymerized para-aramid fiber according to claim 1, wherein the copolymerized para-aramid polymer has an intrinsic viscosity (IV) of 3.5 to 5.5. delete delete