KR101902524B1 - Meta-Aramid Fiber having High elastic rate and Method for Preparing the Same - Google Patents

Abstract

The present invention relates to a meta-aramid fiber having a high modulus of elasticity, which is formed by composite spinning of a high-viscosity meta-aramid resin and a low-viscosity meta-aramid resin in a side-by-side manner and spontaneously shrinks the meta-aramid resin due to viscosity difference.

Description

TECHNICAL FIELD The present invention relates to a meta-aramid fiber having a high modulus of elasticity and a method for producing the same,

The present invention relates to a meta-aramid fiber having a high modulus of elasticity and a method for producing the same, and more particularly, to a meta-aramid fiber having a high modulus of elasticity and a high modulus of elasticity using two kinds of meta-aramid resins having different relative viscosities.

Aromatic polyamides, developed in the 1960s, were developed to improve the heat resistance of nylon, an aliphatic polyamide. Aromatic polyamides, well known for their trade names such as Nomex and Kevlar, And has excellent heat resistance and high tensile strength which can be used for fibers such as cord.

A common aliphatic polyamide is a synthetic resin in which an aliphatic hydrocarbon is bonded to an amide, and an aramid is a synthetic resin in which an amide bond of 85% of benzene groups is bonded to two aromatic rings between amide groups. The aliphatic hydrocarbon of the aliphatic polyamide easily undergoes molecular motion when heat is applied, whereas the benzene ring of the aromatic polyamide is stable to heat and has a high elastic modulus because the molecular chain is rigid and molecules do not easily move even when heat is applied. And there are many differences in characteristics.

In particular, the meta-aramid is represented by Nomex developed by DuPont and Conex developed by Dejin. The meta-based aramid has a merit that the strength and elongation of the benzene ring are combined with the amide group at the meta-position, similar to ordinary nylon, but very good in heat stability, and light and sweat-absorbing compared to other heat-resistant materials. It is used as heat-resistant clothing materials such as fire fighting uniforms, uniforms for racing motorists, astronaut uniforms, and work clothes, and is used for high-temperature filters in industrial applications.

In order to utilize the above-mentioned meta-aramid as a fiber in various fields, a method of mixing with other fibers to enhance the functionality has been proposed. As a part of this, Korean Patent Publication No. 1990-0010102 discloses a method for producing aramid fibers and polybenzimidazole fibers A refractory consisting of an examination of the selected heat-resistant fibers from the group consisting of the endothelial radiation of the examination of the cold-resistant fiber which is wrapped around the examination, and of the cold-resistant fiber which is wrapped around the endo- Korean Patent Laid-Open Publication No. 2008-0062319 discloses an examination of heat-resistant fibers selected from aramid fibers, polybenzimidazole fibers and thermally stabilized and oxidized polyacrylonitrile fibers. The high strength, touch feeling, Be stability suggests the manufacture of protective clothing that covered core spun yarn obsessed configuration with excellent fiber.

In recent years, meta-aramid fibers have been demanded by various industries for meta-aramid fibers having different functions in addition to high heat resistance and flame retardancy. However, the conventional products have a problem in that inherent heat resistance and flame retardancy of the meta-aramid fiber are deteriorated because the functionalities are imposed by using the meta-aramid fiber and the other synthetic fibers in combination.

 The demand of meta-aramid fibers with high elasticity and crimp like general synthetic fibers is increasing, but the meta-aramid fibers developed to date have not satisfied consumer's desires with low elasticity.

The present invention has been made in order to solve the problems of the prior art as described above, and it is an object of the present invention to provide a thermoplastic resin composition which uses two kinds of meta-aramid resins having different relative viscosities and forms a meta-aramid fiber with a side- To provide a meta-aramid fiber.

It is another object of the present invention to provide a production method capable of producing the meta-aramid fiber having a high modulus of elasticity.

The present invention provides a meta-aramid fiber having a high modulus of elasticity, which is formed by co-spinning a high-viscosity meta-aramid resin and a low-viscosity meta-aramid resin in a side-by-side manner.

Also, the high-viscosity meta-aramid resin has a relative viscosity of 2.0 to 3.0, and the low-viscosity meta-aramid resin has a relative viscosity of 1.0 to 2.0.

The present invention also provides a meta-aramid fiber having a high modulus of elasticity, wherein the relative viscosity difference between the high-viscosity meta-aramid resin and the low-viscosity meta-aramid resin is 0.2 to 0.8.

The present invention also provides a method for preparing a meta-aramid fiber having a high modulus of elasticity, comprising: preparing a meta-aramid resin having a relative viscosity of 2.0 to 3.0 and a low-viscosity meta-aramid resin having a relative viscosity of 1.0 to 2.0; A spinning process in which the high-viscosity meta-aramid resin and low-viscosity meta-aramid resin are spun by wet spinning in a coagulating solution, and the composite spinning is performed in a side-by-side manner; A first stretching step of stretching the meta-aramid fiber in the coagulation liquid; A water washing step of washing and drying the drawn meta-aramid fiber; And a second stretching step of stretching the washed meta-aramid fibers by using a heat roller or a heat chamber. The present invention also provides a method of producing meta-aramid fibers having a high modulus of elasticity.

Also, a difference in relative viscosity between the high-viscosity meta-aramid resin and the low-viscosity meta-aramid resin is 0.2 to 0.8. The present invention provides a method for producing a meta-aramid fiber having a high modulus of elasticity.

Also, the first stretching step is characterized in that stretching is performed at a stretching ratio of 1.5 to 2.5. The present invention also provides a method for producing a meta-aramid fiber having a high modulus of elasticity.

Also, the second stretching step is a stretching method at a stretching ratio of 1.5 to 2.0 at a temperature of 350 to 370 DEG C, and provides a method for producing a meta-aramid fiber having a high modulus of elasticity.

As described above, the present invention uses two types of meta-aramid resins having different relative viscosities of meta-aramid fibers having a high modulus of elasticity, and has an excellent modulus of elasticity by forming meta-aramid fibers with side-by-side type conjugate fibers.

Further, there is an effect of providing an optimum manufacturing method capable of producing meta-aramid fibers having a high modulus of elasticity and a high modulus of elasticity.

1 is a view showing a cross-sectional shape of a meta-aramid fiber having a high modulus of elasticity according to the present invention.
2 is a process diagram of a method for producing a meta-aramid fiber having a high modulus of elasticity according to the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. First, it should be noted that, in the drawings, the same components or parts have the same reference numerals as much as possible. 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.

FIG. 1 is a cross-sectional view of a meta-aramid fiber having a high modulus of elasticity according to the present invention, and FIG. 2 is a process diagram of a method of producing meta-aramid fibers having a high modulus of elasticity according to the present invention.

The present invention relates to a meta-aramid fiber having a high modulus of elasticity, which is formed by composite spinning of a high-viscosity meta-aramid resin (100) and a low-viscosity meta-aramid resin (200) side by side as shown in FIG.

As described above, according to the present invention, the difference in viscosity between the high-viscosity meta-aramid resin (100) and the low-viscosity meta-aramid resin (200) improves the modulus of elasticity of the meta-aramid fiber.

Preferably, the high viscosity meta-aramid resin has a relatively viscosity (RV) of 2.0 to 3.0 and the low viscosity meta-aramid resin has a relative viscosity of 1.0 to 2.0. The relative viscosity of the high viscosity meta-aramid resin and the low viscosity meta-aramid resin The viscosity difference is preferably 0.2 to 0.8.

When the relative viscosity difference between the high-viscosity meta-aramid resin and the low-viscosity meta-aramid resin is less than 0.2, the elastic modulus may be low due to insufficient crimp development. If the relative viscosity difference exceeds 0.8, the high- The aramid resin may be separated from each other, and the yarn phenomenon may occur, which may degrade the processability.

The meta-aramid resin is a 1: 1 molar ratio of M-phenylene diamine (MPD) and isophthaloyl chloride (IPC). The meta- The relative viscosity can be controlled by preparing a meta-aramid resin by primary and secondary polymerization processes in which the input amount of chloride (IPC) is divided into two portions.

 That is, isopthaloyl chloride (IPC) in an amount of 70 to 90 mol% relative to meta-phenylenediamine (MPD) was added to meta-phenylenediamine (MPD) The relative viscosity of the meta-aramid resin can be controlled by introducing isophthaloyl chloride (IPC) in an amount of 10 to 30 mol% based on the molybdenum (MPD), and the amount of isophthaloyl chloride IPC) is higher, the relative viscosity becomes higher.

For example, a high-viscosity meta-aramid resin is prepared by adding 80 to 90 mol% of isophthaloyl chloride (IPC) to meta-phenylenediamine (MPD) in meta-phenylenediamine (MPD) (MPC) to meta-phenylenediamine (MPD) in the first stage polymerization, and the addition of isopthaloyl chloride (IPC) in an amount of 10 to 20 mol% 70 to 80 mol% of isophthaloyl chloride (IPC) may be added, and 20 to 30 mol% of isophthaloyl chloride (IPC) may be added in the second polymerization.

The present invention can be applied to a peanut-shaped cross-section as shown in Fig. 1 (a) or a side-by-side cross-sectional view as shown in Fig. 1 (b) by using the high-viscosity meta-aramid resin 100 and the low- Shaped composite fibers.

The meta-aramid fiber having a high modulus of elasticity as described above is prepared by a meta-aramid resin preparing step, a spinning step, a first drawing step, a washing step, and a second drawing step as shown in FIG.

The meta-aramid resin preparation process is a process of preparing a high-viscosity meta-aramid resin having a relative viscosity of 2.0 to 3.0 and a low-viscosity meta-aramid resin having a relative viscosity of 1.0 to 2.0. An aramid resin may be prepared and prepared.

The spinning process is a process of spinning the high-viscosity meta-aramid resin and the low-viscosity meta-aramid resin by wet spinning in a coagulation bath. The present invention is combined with side-by-side spinning to produce meta-aramid fibers.

When irradiated using a meta-aramid resin, the meta-aramid is dissolved in a polar amide solvent and mixed with a solvent.

The viscosity of the meta-aramid dope can be controlled according to the mixing ratio of the polar amide-based solvent and the meta-aramid, and it is preferable to control the mixing ratio of the polar amide-based solvent and the meta-aramid to be suitable for spinning. The methacrylamide dope preferably contains 5 to 30% by weight of meta-aramid in the polar amide solvent, more preferably 15 to 25% by weight of meta-aramid.

The polar amide solvent may be selected from the group consisting of dimethylacetamide (DMAc), N-methylpyrrolidone (NMP), dimethyl formamide (DMF), and dimethyl imidazolidinone Any one of the compounds may be used, and it is preferable to use dimethylacetamide having the most excellent effect.

The high-viscosity meta-aramid resin and the low-viscosity meta-aramid resin of the present invention are mixed with a polar amide solvent as described above, and are produced as respective meta-aramid dope and radiated.

The meta-aramid fibers of the present invention are radiated by wet spinning, which is made into fibers by composite spinning in a coagulating solution at 20 to 80 ° C. The coagulating solution is a mixture of a polar amide solvent and water. The polar amide solvent is dimethylacetamide Dimethyl formamide (DMF), or dimethyl imidazolidinone may be used as the organic solvent, and examples of the organic solvent include dimethylformamide, N-methylpyrrolidone, N-methylpyrrolidone, In the present invention, it is preferable to use dimethylacetamide. It is preferable to mix 20 to 60% by weight of dimethylacetamide (DMAc) and 40 to 80% by weight of water.

The first drawing step is a step of drawing the irradiated meta-aramid fibers in the coagulating solution, and can be carried out in the same manner as the drawing process of the meta-aramid fibers through general wet spinning.

It is preferable that the stretching ratio in the first stretching step is 1.5 to 2.5.

The water washing step is a step of washing and drying the drawn meta-aramid fibers and removing polar amide-based solvents and salts contained in the meta-aramid fibers, and may be carried out by washing and washing with common meta-aramid fibers.

In the second stretching step, the washed meta-aramid fibers are stretched using a heat roller or a heat chamber. In the second stretching step, the meta-aramid fibers of the present invention exhibit a crimp due to a difference in spontaneous shrinkage due to a difference in viscosity.

The second stretching step may be performed by heating at a high temperature of 350 to 370 DEG C through a heat roller or a heat chamber, and the stretching ratio may preferably be 1.5 to 2.0.

If the temperature is less than 350 ° C in the second stretching step, the spontaneous shrinkage due to the viscosity difference is insignificant and the elastic modulus may be lowered. If the temperature is higher than 370 ° C, the physical properties of the meta-aramid fiber may be deteriorated.

If the stretching ratio exceeds 2.0 in the second stretching step, the degree of orientation of the meta-aramid resin increases and the degree of crystallization increases, so that the modulus of elasticity may be lowered. It is preferable that the stretching ratio in the second stretching step does not exceed 2.0.

It is preferable not to perform the heat fixation after the second stretching process with the meta-aramid fiber having the high modulus of elasticity by the appearance of the crimp through the second stretching process performed at the high temperature as described above. If heat setting is performed after the second stretching step, the oriented meta-aramid fibers may be reoriented to lower the elastic modulus.

Hereinafter, embodiments of the method for producing a meta-aramid fiber having a high modulus of elasticity according to the present invention will be described, but the present invention is not limited thereto.

Example  1, 2

A high-viscosity meta-aramid resin and a low-viscosity meta-aramid resin were prepared. Then, the high-viscosity meta-aramid resin and the low-viscosity meta-aramid resin were dissolved in dimethylacetamide, Aramid meta aramid dopes were formed.

The high-viscosity meta-aramid meta-aramid dope and the low-viscosity meta-aramid meta-aramid dope are mixed with a solution of 40 wt% of dimethylacetamide and 60 wt% of water, And the first stretching step was carried out at a stretching ratio of 2.0 in the same coagulating solution.

The elongated meta-aramid fibers were washed and dried, and the water-treated meta-aramid fibers were subjected to a second stretching process in a high-temperature heat chamber to produce meta-aramid fibers having a high elastic modulus according to the present invention .

Table 1 shows the relative viscosities of the high-viscosity meta-aramid resin and the low-viscosity meta-aramid resin according to Examples 1 and 2, the draw ratio in the second draw process, and the draw temperature in the second draw process.

Comparative Example  1 to 4

The meta-aramid fibers were prepared in the same manner as in Example 1 except that the relative viscosity difference, stretching ratio and stretching temperature of the meta-aramid resin were different.

Table 1 shows the relative viscosity of the meta-aramid resin used in Comparative Examples 1 to 4, the stretching ratio in the second stretching process, and the stretching temperature in the second stretching process.

division Example 1 Example 2 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Low viscosity resin (RV) 1.8 2.0 2.0 2.4 1.8 1.8 High Viscosity Resin (RV) 2.4 2.2 2.0 2.4 2.4 2.4 The stretching ratio of the second stretching 2.0 2.0 2.0 2.0 3.0 2.0 Stretching temperature (占 폚) 360 360 360 360 360 320

The relative viscosity (RV) of the meta-aramid resin was measured by ASTM-1P-200 method using sulfuric acid as the solvent and Kenon-Fensk type capillary viscometer. The time (t0) of the pure solvent passing through the capillary viscometer and the time (t) of the polymer solution were measured in a thermostatic bath at 35 ± 0.01 ° C, and the relative viscosity (RV) was determined using the following equation.

RV = t / t0

◈ Evaluation of modulus of meta-aramid fiber

The strength and modulus of elasticity of Examples 1 and 2 and Comparative Examples 1 to 4 were measured and evaluated.

 The strength was measured with a loudness meter (Instron 5564) -ASTM D885 and the modulus was measured with a universal tensile tester (Instron 4200 / 430C Machine).

division Example 1 Example 2 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 De ' 1.48 1.47 1.5 1.49 1.45 1.51 Strength (g / d) 4.89 4.91 4.89 5.1 5.12 5.04 Modulus of elasticity (gf) 489 358 254 281 287 248

As shown in Table 2, it can be seen that Examples 1 and 2, which are meta-aramid fibers having a high elastic modulus of the present invention, have a higher modulus of elasticity than the meta-aramid fibers of Comparative Examples 1 to 4.

In Comparative Examples 1 to 4, all of the Comparative Examples 1 and 2 did not exhibit the improvement in the modulus of elasticity because the crimp was not expressed. In Comparative Examples 1 and 2, the meta-aramid resin having the same relative viscosity was prepared as a side biside type. In Comparative Example 3, the degree of orientation of the meta-aramid fiber was too high to induce the appearance of the crimp. In Comparative Example 4, in the second stretching process, spontaneous shrinkage due to viscosity difference It is expected that the crimp is not expressed.

Accordingly, it can be seen that the stretching temperature and the stretching ratio are very important factors in the second stretching process of the meta-aramid fiber having a high modulus of elasticity.

Claims (7)

A high-viscosity meta-aramid resin and a low-viscosity meta-aramid resin are combined and spun in a side-by-side manner,
Wherein the relative viscosity difference between the high-viscosity meta-aramid resin and the low-viscosity meta-aramid resin is 0.2 to 0.8. The method according to claim 1,
Wherein the high viscosity meta-aramid resin has a relative viscosity of 2.0 to 3.0 and the low viscosity meta-aramid resin has a relative viscosity of 1.0 to 2.0. delete A method for producing a meta-aramid fiber having a high modulus of elasticity,
A high viscosity meta-aramid resin having a relative viscosity of 2.0 to 3.0 and a low viscosity meta-aramid resin having a relative viscosity of 1.0 to 2.0. The high viscosity meta-aramid resin and the low viscosity meta-aramid resin have a relative viscosity difference of 0.2 to 0.8. A meta-aramid resin preparation process for preparing a low-viscosity meta-aramid resin;
A spinning process in which the high-viscosity meta-aramid resin and low-viscosity meta-aramid resin are spun by wet spinning in a coagulating solution, and the composite spinning is performed in a side-by-side manner;
A first stretching step of stretching the meta-aramid fiber in the coagulation liquid;
A water washing step of washing and drying the drawn meta-aramid fiber;
And a second stretching step of stretching the washed meta-aramid fibers by using a heat roller or a heat chamber. delete 5. The method of claim 4,
Wherein the first stretching step is a stretching at a stretching ratio of 1.5 to 2.5. 5. The method of claim 4,
Wherein the second stretching step is a stretching at a stretching ratio of 1.5 to 2.0 at 350 to 370 占 폚.

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