KR20110078895A - Aromatic diamine, aramid polymer and method for manufacturing the same - Google Patents

Abstract

PURPOSE: An aromatic diamine, an aramid polymer and a method for manufacturing the same are provided to ensure an excellent color property by preventing oxidation as an antioxidant such as hydrazine is included and to prepare an aramid polymer with narrow molecular weight distribution. CONSTITUTION: A method for preparing an aromatic diamine comprises the steps of: adding antioxidants to aromatic diamine; and purifying aromatic diamines to which antioxidant is added. The antioxidants are hydrazine. A purifying process is performed by a heat distillation method. The method further includes a step for adding organic solvents with the boiling point lower than that of aromatic diamine.

Description

Aromatic diamine, Aramid polymer and Method for manufacturing the same

The present invention relates to an aromatic diamine, an aramid polymer and a method for producing the same, and more particularly to an aromatic diamine, an aramid polymer having a high purity and preventing the formation of oxidized aromatic diamine.

In general, the wholly aromatic polyamide, commonly referred to as aramid, includes para-aramid and meta-aramid which have a structure in which the benzene rings are connected linearly through an amide group (CONH). Para-based aramis have excellent properties such as high strength, high elasticity, and low shrinkage.The 5mm thick thin yarn manufactured therefrom has a strong strength enough to lift 2 tons of cars and is not only used for bulletproof applications. It is used in a variety of applications in the high-tech industry in the aerospace field. In addition, aramid is carbonized at 500 ° C or higher, and therefore has been in the spotlight in fields requiring high heat resistance.

Usually, such aramid is prepared by dissolving aromatic diamine in a polymerization solvent to prepare a mixed solution, and then adding the aromatic dieside to the prepared mixed solution to polymerize it.

On the other hand, in order to use aramid in the production of various products, excellent color characteristics and physical properties are required.

However, aromatic diamine, which is a raw material of the conventional aramid polymer, has a high reactivity and is oxidized in contact with oxygen, thereby degrading color characteristics.

In addition, the conventional aromatic diamine has a high content of impurities, the aramid polymer prepared therefrom has a problem of low molecular weight and wide molecular weight distribution.

Thus, the molded article produced therefrom suffers from the problem of losing the customer's trust as the physical properties deteriorate.

Accordingly, there is a need for the development of a manufacturing technique of aromatic diamine for producing aramid polymer having excellent physical and color properties.

The present invention was derived to solve the above problems, the present invention, by purifying the aromatic diamine in the state of addition of an antioxidant such as hydrazine and an organic solvent, it is possible to obtain a high-purity aromatic diamine and thus An aramid polymer prepared from an aromatic diamine is to provide an aromatic diamine, an aramid polymer and a method for producing the same, which can be used in various fields due to its excellent molecular weight distribution and color characteristics.

In order to achieve the above advantages, and in accordance with the object of the present invention, one aspect of the present invention is a process for adding an antioxidant to the aromatic diamine; And it provides a method for producing an aromatic diamine comprising the step of purifying the aromatic diamine to which the antioxidant is added.

Other aspects of the present invention include oxidized aromatic diamines of up to 10 ppm; And 5 ppm or less of chloroaniline.

Another aspect of the invention is a purified aromatic diamine comprising up to 10 ppm oxidized aromatic diamine and up to 5 ppm chloroaniline; And a process for polymerizing the aromatic dieside halide is provided.

The present invention has the following effects.

First, the aromatic diamine according to the present invention has an excellent color characteristics by preventing oxidation as it includes an antioxidant such as hydrazine.

Second, the aromatic diamine according to the present invention according to the present invention has a high purity can produce aramid polymer having a narrow molecular weight distribution.

Third, the aramid polymer having such physical and color properties can be used to produce a variety of molded articles, such as fibers, films, plastics.

Such molded bodies may be used in various fields such as electronics, environment, sports, bulletproofing, aircraft, automobiles, construction and civil engineering.

Hereinafter, the aromatic diamine, the aramid polymer of the present invention and the production method thereof will be described in detail.

First, an aromatic diamine and its manufacturing method will be described.

Aramid polymers are prepared by polymerizing aromatic diamines and aromatic dieside halides. Accordingly, in order to obtain an aramid polymer having excellent physical properties, ie, high molecular weight and narrow molecular weight distribution, the raw materials, aromatic diamine and aromatic dieside halide, must have high purity. In particular, since the aromatic diamine contains a large amount of impurities which are by-products during the manufacturing process, when the polymerization is performed in a state in which such a large amount of impurities are contained, the aramid polymer produced is significantly inferior in physical properties. That is, when one raw material aromatic diamine contains a large amount of impurities such as chloroaniline, the chloroaniline serves as a polymerization terminator to lower the molecular weight and widen the molecular weight distribution.

As above, the purity of the aromatic diamine has a great influence on the physical properties of the final product. That is, when a molded article such as aramid fibers is manufactured using an aramid polymer having a low molecular weight and a wide molecular weight distribution, the prepared aramid fibers have a sharp drop in strength and elastic modulus and a large deviation thereof. Products made from aramid fibers having poor physical properties may lose reliability from customers as they do not sufficiently exhibit the required performance. For example, a body armor made from aramid fibers having low strength may not have sufficient bulletproof performance from bullets and the like, which may cause a problem in which human safety cannot be guaranteed.

Accordingly, in order to obtain an aramid polymer having a high molecular weight and a narrow molecular weight distribution as described above, the aromatic diamine as a raw material should have high purity.

Therefore, an efficient purification method for preparing aromatic diamine having high purity will be described.

Purification of the aromatic diamine can be carried out smoothly through the thermal distillation method.

The aromatic diamine to be purified may comprise various compounds. For example, the aromatic diamine may be paraphenylenediamine or metaphenylenediamine, the paraphenylenediamine has a boiling point of 302 ° C, and the metaphenylenediamine has a boiling point of 283 ° C.

Meanwhile, the impurities may also include various compounds. For example, the impurity may be aniline or parachloroaniline, the aniline has a boiling point of 184.4 ° C., and the parachloroaniline has a boiling point of 230 ° C. As described above, since the aromatic diamine and the impurity have different boiling points, the impurities can be easily separated from the aromatic diamine by the thermal distillation method.

This thermal distillation is carried out by heating the aromatic diamine into a distillation column, and heating. The aromatic diamine and the impurities are separated from each other by the difference in boiling point. That is, aromatic diamine having a high boiling point is located at a low position of the distillation column, and impurities having a low boiling point are located at a high position of the distillation column. The aromatic diamine and impurities are separated by connecting a pipe to each position.

If the boiling point between the aromatic diamine and the impurity is not large, it may be difficult to obtain an aromatic diamine having a high degree of purity required by the industry in one purification, and thus, the second or third refinement may be performed. Done. By performing a plurality of refining as described above, not only the economy is lowered, but also the production of the highest purity aromatic diamine may be difficult.

Accordingly, the present invention performs a process of adding an organic solvent to the aromatic diamine before the purification process. As a result, impurities can be easily separated from the aromatic diamine.

Such an organic solvent preferably has a boiling point lower than that of the aromatic diamine. That is, the added organic solvent serves to help the impurities easily separate from the aromatic diamine by having a boiling point lower than that of the aromatic diamine and having a boiling point similar to that of the impurities.

The organic solvent may be water, methanol, ethanol, benzene, toluene, N-methyl-2-pyrrolidone (NMP), N, N-dimethylacetamide (DMAc), N, N-dimethylformamide (DMF), or Dimethylsulfoxide (DMSO) and the like.

The organic solvent may be added within a range of 1 to 100,000 times the weight of the impurity. If the amount of the organic solvent added is less than 1 times, impurities may not be easily separated from the aromatic diamine. On the other hand, if the amount of the organic solvent added exceeds 100,000 times, the separation effect may not increase and only the cost may increase. have.

As such, by adding an organic solvent to purify the aromatic diamine, an aromatic diamine having a high level of purity required in one purification step can be obtained, thereby reducing the cost of purification and reducing the purification time, thereby improving economic efficiency. have.

The aromatic diamine prepared by the above process may have an chloroaniline concentration of 5 ppm or less as an impurity. The chloroaniline includes parachloroaniline.

However, when the aromatic diamine is purified by thermal distillation as described above, the aromatic diamine is exposed to air containing oxygen in a high temperature state. When the aromatic diamine is exposed to oxygen during such a purification process, the aromatic diamine is highly reactive and is easily reacted with oxygen and oxidized to be converted into a nitro compound. The aramid polymer prepared using this oxidized aromatic diamine has a deterioration in color characteristics, i.e. a dark color. Molded bodies made from aramid polymers with reduced color properties are less reliable from customers.

Therefore, the purification process of the aromatic diamine of the present invention comprises the step of adding an antioxidant to the aromatic diamine. This prevents oxygen and aromatic diamine from contacting during the purification process. That is, the antioxidant having a better reactivity than the aromatic diamine first encounters oxygen to cause an oxidation reaction, thereby preventing the oxidation reaction as the aromatic diamine is blocked from being exposed to oxygen.

The antioxidant includes hydrazine. The hydrazine antioxidant reacts with the aromatic diamine and oxygen in the air by the following reaction to remove oxygen.

Scheme 1

N ₂ H ₄ + O ₂ → N ₂ + 2H ₂ O

In addition, the anti-inflammatory agent may be a hydrazine compound represented by the following formula (1).

[Formula 1]

R ₁ R ₂ N-NR ₃ R ₄

In this case, R ₁ , R ₂ , R ₃ and R ₄ are independently an aliphatic group, aromatic group, halogen atom, hydroxyl group, nitro group, nitroso group, cyano group, amino group, imino group, azo group, carbonyl group, carboxyl group , Acyl group, alkoxycarbonyl group, aryloxycarbonyl group, carbamoyl group, alkoxyl group, aryloxy group, haloalkyl group, mercapto group, alkylthio group, arylthio group, sulfo group, sulfinyl group, sulfonyl group or heterocyclic group Can be. In addition, the two substituents selected from R ₁ , R ₂ , R _3, and R ₄ may be ring compounds formed by arbitrarily bonding with each other.

The aromatic diamine prepared by the above process may have a concentration of oxidized aromatic diamine of 10 ppm or less.

Through this purification process, high-purity para-phenylenediamine, meta-phenylenediamine, 4,4'-diaminobiphenyl, 1,3-diaminobiphenyl, 2,6-naphthalenediamine, 1,5- Aromatic diamines such as naphthalenediamine or 4,4'-diaminobenzanilide may be prepared.

Next, an aramid polymer and its manufacturing method are demonstrated.

First, the aromatic diamine purified as described above is dissolved in a polymerization solvent to prepare a mixed solution.

The purified aromatic diamine has up to 5 ppm chloroaniline and up to 10 ppm oxidized aromatic diamine.

Such a polymerization solvent is prepared by adding an inorganic salt to an organic solvent. As the organic solvent, an amide organic solvent, a urea organic solvent, or a mixed organic solvent thereof may be used. Specific examples thereof include N-methyl-2-pyrrolidone (NMP), N, and N'-dimethylacetate. Amide (DMAc), hexamethylphosphoramide (HMPA), N, N, N ', N'-tetramethyl urea (TMU), N, N-dimethylformamide (DMF) or mixtures thereof.

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

Subsequently, an aromatic dieside halide is prepared.

Specific examples of the aromatic dieside halide include terephthaloyl dichloride, 4,4'-benzoyl dichloride, 2,6-naphthalenedicarboxylic acid dichloride or 1,5-naphthalenedicarboxylic acid dichloride, but are not necessarily It is not limited.

Subsequently, a small amount of the aromatic dieside halide prepared to the mixed solution is added to the mixed solution while the mixed solution is preliminarily polymerized.

In the polymerization of the aromatic diamine and the aromatic dieside halide, the reaction proceeds at a high rate with exotherm. In this way, when the polymerization rate is high, there is a problem in that the degree of polymerization differs between the finally obtained polymers. More specifically, since the polymerization reaction does not proceed simultaneously in the entire mixed solution, the polymer that has first started the polymerization proceeds rapidly to form a long molecular chain, whereas the polymer that has started the polymerization first polymerizes first. There is no choice but to form shorter molecular chains than the polymer from which the reaction was initiated, and the higher the polymerization rate, the greater the difference. As such, when the degree of polymerization difference between the polymers finally obtained increases, physical property variations also increase, making it difficult to achieve desired characteristics. Therefore, it is preferable to minimize the difference in degree of polymerization between the polymers finally obtained by preforming a prepolymer having a molecular chain of a predetermined length through a prepolymerization step, and then performing a polymerization step.

According to one embodiment of the invention, the prepolymerization process is carried out while maintaining the reaction temperature at 0 ~ 60 ℃ in the reactor, the reaction time gives a sufficient polymerization time of about 1 minute to 5 hours, the production of aramid polymer It is preferable to add only 20 to 50% of the total amount of the aromatic dieside halide required in the prepolymerization step.

After completion of the prepolymerization process, the temperature is lowered to 0 to 40 ° C. and the aromatic dieside halide is further added to the prepolymer to prepare a final polymer.

Since aromatic dieside halides react with aromatic diamines in a 1: 1 molar ratio when preparing aramid polymers, the amount of aromatic dieside halides added in the final polymerization is the same mole as the aromatic diamines when added to the amount added during prepolymerization. Is determined to be. However, when preparing the polymerization solvent, a small amount of water added to assist in dissolving the inorganic salt may remain even after the dehydration process, in which case a small amount of water may react with the aromatic dieside halide to form an insoluble substance. Therefore, in view of the formation of such an insoluble substance, a small amount of aromatic dieside halide may be added more than aromatic diamine.

Specific examples of the aramid polymer obtained by the polymerization step include poly (paraphenylene terephthal-amide: PPD-T), poly (methphenylene terephthal-amide: PPD-M), and poly (4,4'-benzanilide Terephthalamide), poly (1,3-benzanilide terephthalamide), poly (paraphenylene-4,4'-biphenylene-dicarboxylic acid amide) or poly (paraphenylene-2,6-naphthalenedi Carboxylic acid amide).

The aramid polymer prepared through the above process has a uniform molecular weight as the molecular weight distribution is narrow, the product produced therefrom exhibits excellent physical properties. In addition, since the aramid polymer does not have a dark color, reliability can be obtained from customers.

The aramid polymer prepared as described above can be produced in various shaped bodies. Examples of such molded articles include filters, fibers, films, nonwoven fabrics, plastics, and the like, but are not necessarily limited thereto.

Hereinafter, the present invention will be described in detail through examples and comparative examples. However, the following examples are only intended to help the understanding of the present invention, and the scope of the present invention should not be limited thereto.

Aromatic Diamine  Produce

Example  One

Toluene, an organic solvent, was added to the aromatic diamine, p-phenylenediamine, to 50% by weight of the organic solvent, and 5% by weight of the antioxidant hydrazine compared to the paraphenylenediamine. This mixture was then thermally distilled in a distillation column to obtain purified paraphenylenediamine.

Example  2 to 6

In Example 1 described above, purification was carried out in the same manner as in Example 1, except that the concentration of the hydrazine, the antioxidant, was added at 1, 20, 50, 70, and 90% by weight relative to the paraphenylenediamine. Obtained paraphenylenediamine.

Comparative example  One

As in Example 1 described above, paraphenylenediamine was used without addition of an antioxidant and without purification.

The purity of each paraphenylenediamine prepared by the above Examples and Comparative Examples, that is, the content of chloroaniline and oxidized aromatic diamine was measured by the following method, and the measurement results are shown in Table 1.

Of paraphenylenediamine  undergarment Chloroaniline  And oxidized aromatics Diamine  Content measurement

Quantification was carried out using gas chromatography (GC) according to the following conditions and procedures to determine the content of ppm of chloroaniline and oxidized aromatic diamine in paraphenylenediamine.

The measurement conditions of the gas chromatography are as follows.

1) Measuring device: Agilent 6890

2) Integration: GC Chemstation

3) Carrier gas: He

4) Flow: 1.5ml / min

5) Split ratio: 10: 1 (15ml / min)

6) Injection concentration: 10wt% SMPL in 99.9% Methanol

7) Colume: Rtx-1701, 30m × 0.32㎜ × 1.0㎛

8) Temperature profile: injector 280 ℃, detector 280 ℃, 40 minutes × 140 ℃, 30 ℃ / min to 240 ℃, 20 minutes × 240 ℃

The measurement sequence of the gas chromatography is as follows.

1) The prepared paraphenylenediamine is completely dissolved in reagent grade methanol having a purity of 99.99% to make a sample of 10 wt%.

2) The sample is introduced using a syringe, and quantitative analysis is performed under the above-described conditions.

division Hydrazine Concentration (wt%) Chloroaniline content (ppm) Oxidized Aromatic Diamine Content (ppm) Example 1 5 4 10 Example 2 One 4 10 Example 3 20 4 9 Example 4 50 5 9 Example 5 70 5 9 Example 6 90 5 9 Comparative Example 1 0 37 618

Preparation of Aramid Polymer

Example  7

Under a nitrogen atmosphere, N, N-dimethylacetamide, which is a polymerization solvent, is added to the reactor, and the mixed solution is prepared by dissolving the paraphenylenediamine prepared in Example 1 in the reactor. Subsequently, 40 mol% of terephthaloyl dichloride was added to the reactor containing the mixed solution to prepare a prepolymer, and then 60 mol% of the remaining terephthaloyl dichloride was added to the reactor containing the prepolymer. After addition to the reaction, water is added to extract the polymer, and the extracted polymer is dehydrated and dried to prepare an aramid polymer.

Example  8 to 12

An aramid polymer was prepared in the same manner as in Example 7, except that paraphenylenediamine prepared in Examples 2 to 6 was used.

Comparative example  2

An aramid polymer was prepared by the same method as Example 7 except for using the paraphenylenediamine prepared by Comparative Example 1 described above.

Color L * value and molecular weight distribution of each paraphenylenediamine prepared by the above Examples and Comparative Examples were measured using the following method, the results are shown in Table 2.

Determination of Color L * Value of Aramid Polymers

In order to measure the degree of discoloration of the aramid polymer, a color L * value that can be expressed indirectly was measured. The color L * value was obtained using a colorimeter (manufacturer: Minolta) with model name Chromater CR-300.

Molecular weight distribution ( PDI ) Measure

(i) Synthesis of Aramid Polymer Derivatives

Put an aramid polymer and potassium ter-butoxide in dimethyl sulfoxide, dissolve it under normal temperature and nitrogen atmosphere, add allyl bromide, and react. (Macromolecules 2000, 33, 4390).

(Ii) measurement of molecular weight distribution

The aramid polymer derivative was dissolved in tetrahydrofuran (THF) to prepare a sample, and the prepared sample was subjected to Shodex of a Waters manual injector kit at a temperature of 35 ° C. and a flow rate of 10 ml / min. Using a (Shodex) GPC column to obtain the weight average molecular weight and number average molecular weight in a gel permeation chromatography equipped with a refractive index detector (Refraction Index detector), from the molecular weight using the following equation (1) Measure the distribution.

[Equation 1]

Molecular Weight Distribution = Mw / Mn

At this time, Mw is a weight average molecular weight, Mn is a number average molecular weight.

division Color L * Value Molecular weight distribution Example 7 76.8 1.85 Example 8 77.0 1.92 Example 9 77.1 1.83 Example 10 76.9 1.84 Example 11 76.2 1.85 Example 12 76.2 1.84 Comparative Example 2 73.2 2.05

Molded  Manufacture: Aramid Fiber

Example  13

The aramid polymer prepared in Example 7 was dissolved in 98% sulfuric acid solvent to produce a spinning dope having a concentration of 20%, and the spinning dope was spun by using a spinneret, and then passed through an air gap in a coagulation bath. The filaments were prepared by coagulation at. Subsequently, aramid fibers were produced by washing the filaments with water, winding them after drying and stretching.

Comparative example  3

Aramid fibers were prepared in the same manner as in Example 13, except that the aramid polymer prepared in Comparative Example 2 was used.

Each aramid fiber prepared by the above Examples and Comparative Examples was measured for strength by the following method, the results are shown in Table 3.

Strength Measurement of Aramid Fiber

Strength was measured according to the ASTM D885 test method. Specifically, the strength of the sample is measured by measuring the strength (g) when a 25 cm long sample is broken in an Instron Engineering Corp. (Canton, Mass) and dividing it by the denier of the sample. Obtained. At this time, the tensile speed was 300 mm / min, the ultra-load was fineness × 1 / 30g. The strength (g / d) of the aramid fibers was obtained from the average value after testing five samples.

division Strength (g / d) Example 13 24.3 Comparative Example 3 23.6

Claims (7)

Adding an antioxidant to the aromatic diamine; And A method for producing an aromatic diamine comprising the step of purifying the aromatic diamine to which the antioxidant is added. The method of claim 1, The antioxidant is a method for producing an aromatic diamine, characterized in that hydrazine. The method of claim 1, The antioxidant is a method for producing an aromatic diamine, characterized in that the hydrazine compound represented by the following formula (1). [Formula 1] R ₁ R ₂ N-NR ₃ R ₄ At this time, the R ₁ , R ₂ , R ₃ and R ₄ , Independently aliphatic, aromatic, halogen, hydroxyl, nitro, nitroso, cyano, amino, imino, azo, carbonyl, carboxyl, acyl, alkoxycarbonyl, aryloxycarbonyl, carbamoyl, alkoxy Real groups, aryloxy groups, haloalkyl groups, mercapto groups, alkylthio groups, arylthio groups, sulfo groups, sulfinyl groups, sulfonyl groups or heterocyclic groups; or Two substituents selected from R ₁ , R ₂ , R _3, and R ₄ are ring compounds formed by arbitrarily bonding with each other. The method of claim 1, The purifying process is a method for producing an aromatic diamine, characterized in that carried out by a thermal distillation method. The method of claim 1, A method for producing an aromatic diamine, further comprising adding an organic solvent having a lower boiling point than the aromatic diamine to the aromatic diamine. 10 ppm or less of oxidized aromatic diamine; And Aromatic diamine comprising up to 5 ppm chloroaniline. Purified aromatic diamines comprising up to 10 ppm oxidized aromatic diamines and up to 5 ppm chloroaniline; And A method for producing an aramid polymer comprising the step of polymerizing an aromatic dieside halide.