KR102586541B1 - Meta aramid fiber improved having physical properties - Google Patents

Abstract

The present invention relates to a meta-aramid fiber formed of meta-phenylene diamine (M-phenylene diamine, MPD) and isophthaloyl chloride (IPC), wherein the meta-aramid fiber satisfies the following formula (2) It relates to meta-aramid fibers with improved physical properties.
Equation (2) OD + YM ≥ 120
However, OD: crystallinity (%), YM: Young's modulus (g/de)

Description

Meta-aramid fiber with improved physical properties {META ARAMID FIBER IMPROVED HAVING PHYSICAL PROPERTIES}

The present invention relates to a meta-aramid fiber with improved physical properties, and relates to a meta-aramid fiber with improved physical properties that can improve the physical properties of the meta-aramid fiber by controlling the conditions of each process during the manufacturing process.

Aromatic polyamide called aramid, developed in the 1960s, was developed to improve the heat resistance of nylon, an aliphatic polyamide. Aromatic polyamide, well known under brand names such as Nomex and Kevlar, is used in flame-retardant textile fabrics and tires. It has excellent heat resistance and high tensile strength that can be used for textile purposes such as cords.

A general aliphatic polyamide is a synthetic resin in which aliphatic hydrocarbons are bonded between amide groups, but aramid is a synthetic resin in which 85% of the amide bonds between amide groups are benzene groups bonded to two aromatic rings. While the aliphatic hydrocarbon of the aliphatic polyamide easily undergoes molecular movement when heat is applied, the benzene ring of the aromatic polyamide has a rigid molecular chain and the molecule does not move easily even when heat is applied, so it is heat stable and has a high elastic modulus, making it a general aliphatic polyamide. It shows many differences in characteristics.

In particular, representative examples of meta-aramid include Nomex developed by DuPont and Conex developed by Teijin. Meta-aramid is a benzene ring bonded to an amide group at the meta position. Its strength and elongation are similar to ordinary nylon, but it has excellent heat stability. It is lighter than other heat-resistant materials and can absorb sweat to a certain extent, so it has the advantage of being comfortable. It is used as a heat-resistant clothing material for firefighting suits, uniforms for racing car drivers, astronaut uniforms, and work clothes, and for industrial purposes, it is used as a high-temperature filter.

As disclosed in Korean Patent No. 1703349, meta-aramid fiber is formed by dissolving meta-aramid polymerized with meta-phenylene diamine and isophthaloyl chloride in a solvent to form meta-aramid dope and spinning the meta-aramid dope into fiber. A polymer solution is prepared by dissolving a meta-type wholly aromatic polyamide containing an m-phenylenediamine isophthalamide unit as a main repeating unit in an amide compound solvent, as in Korea Patent No. 0490219, or prepared by including a fiber forming step. a wet spinning step in which the polymer solution is prepared and extruded in the form of fibers through the orifice of the spinneret into a coagulation bath containing water and an amide compound solvent but substantially free of any salts, and the resulting fibrous polymer solution is coagulated in the coagulation bath. Applying the polymer solution; Subjecting the resulting porous unstretched fiber formed by coagulation to a stretching step in which the fiber is stretched in a plastic stretching bath containing an aqueous solution of an amide compound solvent; The resulting drawn fiber is washed with water; It is prepared by heat treating the washed fibers (e.g., further stretching the fibers to an elongation ratio of 0.7 to 3.0 while heating at 270 to 400° C.).

As described above, most meta-aramid fibers are manufactured through wet spinning, and meta-aramid dope is manufactured through a spinning and stretching process in a coagulating liquid.

The meta-aramid fiber produced as described above was spun in a doped state by dissolving the meta-aramid resin in a solvent, so there was a problem that methods for improving physical properties were very limited.

The present invention was invented to solve the problems of the prior art as described above, and the purpose is to provide meta-aramid fibers with improved physical properties by controlling the process conditions during the wet spinning and stretching process to produce meta-aramid fibers. .

In addition, the purpose is to provide meta-aramid fibers that can be used for various purposes such as textiles, papermaking, and non-woven fabrics due to their high crystallinity and excellent modulus.

The present invention relates to a meta-aramid fiber formed of meta-phenylene diamine (M-phenylene diamine, MPD) and isophthaloyl chloride (IPC), wherein the meta-aramid fiber satisfies the following formula (2) Provides meta-aramid fiber with improved physical properties.

Equation (2) OD + YM ≥ 120

However, OD: crystallinity (%), YM: Young's modulus (g/de)

In addition, the meta-aramid fiber provides a meta-aramid fiber with improved physical properties, characterized in that the crystallinity (%) is 80% or more.

In addition, the meta-aramid fiber provides a meta-aramid fiber with improved physical properties, characterized in that the Young's modulus is 40 g/de or more.

In addition, the meta-aramid fiber provides a meta-aramid fiber with improved physical properties, characterized in that the strength is 4.6 g/de or more.

The meta-aramid fiber with improved physical properties according to the present invention as described above has the effect of improving the physical properties of the meta-aramid fiber by controlling the process conditions during the wet spinning and stretching process to produce the meta-aramid fiber.

In addition, the meta-aramid fiber according to the present invention has an excellent modulus with a high degree of crystallinity, which has the effect of improving the physical properties of the fiber itself when used in spun yarn, fabric, paper, non-woven fabric, etc.

Hereinafter, a preferred embodiment of the present invention will be described in detail. In describing the present invention, detailed descriptions of related well-known functions or configurations are omitted in order to not obscure the gist of the present invention.

As used herein, the terms 'about', 'substantially', etc. are used to mean at or close to the numerical value when manufacturing and material tolerances inherent in the stated meaning are presented, and are used to enhance the understanding of the present invention. Precise or absolute figures are used to assist in preventing unscrupulous infringers from taking unfair advantage of stated disclosures.

In the calculation of the formula disclosed in the present invention, each measured value is converted to the presented unit and then calculated only as a real number of the measured value.

The present invention relates to meta-aramid fibers with improved physical properties such as crystallinity and Young's modulus.

The meta-aramid fiber of the present invention is manufactured including a dope forming step, a spinning step, a stretching step, a washing/drying step, and a hot stretching step like a general meta-aramid fiber manufacturing method.

The dope formation step is a step of forming meta-aramid dope by dissolving meta-aramid polymerized with meta-phenylene diamine (M-phenylene diamine (MPD)) and isophthaloyl chloride (IPC) in a solvent.

In the present invention, a polymerization process for producing meta-aramid by polymerizing meta-phenylene diamine (M-phenylene diamine (MPD)) and isophthaloyl chloride (IPC), and the polymerized meta-aramid in a polar amide-based solvent. Meta-aramid dope can be formed through a solvent mixing process of melting and mixing.

When forming the meta-aramid dope, the viscosity of the meta-aramid dope can be adjusted according to the mixing ratio of the polar amide-based solvent and meta-aramid. It would be desirable to adjust the mixing ratio of the polar amide-based solvent and meta-aramid to be suitable for spinning. . The meta-aramid dope preferably contains 10 to 40% by weight of meta-aramid in the polar amide-based solvent, and more preferably contains 10 to 25% by weight of meta-aramid.

The polar amide-based solvent includes dimethyl acetamide (DMAc), N-methylpyrrolidone (NMP), dimethyl formamide (DMF), and dimethyl imidazolidinone. Any one compound can be used, and it is preferable to use dimethylacetamide, which is most effective.

The spinning step is a step in which the dope is spun into a meta-aramid fiber by spinning it in a coagulating solution containing a polar amide-based solvent.

In the spinning step, it would be desirable to adjust the meta-aramid dope temperature to 50-90°C for spinning.

The coagulating liquid is a mixture of a polar amide-based solvent and water, and the polar amide-based solvent is dimethyl acetamide (DMAc), N-methylpyrrolidone (NMP), and dimethyl formamide (DMF). , Dimethyl imidazolidinone can be used, and in the present invention, it is preferable to use dimethylacetamide.

The concentration of the coagulating solution in the spinning step will preferably contain 35 to 55% by weight of a polar amide-based solvent, and the coagulating solution temperature may be adjusted depending on the meta-aramid dope temperature, but is preferably 10 to 50 ° C. will be.

The spinning speed should be adjusted depending on the concentration of the meta-aramid dope and the concentration of the coagulating liquid, but is preferably 2 to 8 m/min.

The stretching step is a step of stretching the meta-aramid fiber in a coagulating solution containing 20 to 60% by weight of a polar amide-based solvent.

In the stretching step, it is preferable that the stretching multiple (stretch ratio) is 2.5 to 10.

The stretching step may be performed in the same manner as the stretching step of meta-arimid fiber through general wet spinning.

As described above, the dope formed by dissolving meta-aramid polymerized with meta-phenylene diamine (MPD) and isophthaloyl chloride (IPC) in a polar amide-based solvent is mixed with a polar amide-based solvent. Meta-aramid fibers are manufactured by wet spinning and stretching in a coagulating solution.

The method for manufacturing meta-aramid fiber with improved physical properties of the present invention is characterized by a crystallization constant (Oc) calculated by the following equation (1) of 60 or more.

Equation (1) (Dt

However, Ct: coagulating liquid temperature (℃), Dt: dope temperature (℃), Dr: stretching ratio, Cc: coagulating liquid concentration (% by weight), V: spinning speed (m/min).

The stretching multiple is the stretching multiple in the stretching step and does not include the stretching multiple in the hot stretching step.

The crystallization constant (Oc) is the inventor of the present invention extracts five elements that can control the physical properties of meta-aramid fibers during the process of manufacturing meta-aramid fibers, and easily controls the physical properties of meta-aramid fibers through their combination. It is defined as a number that can be done.

When the crystallization constant (Oc) is 60 or more, the manufactured meta-aramid fiber has improved crystallinity and Young's modulus, thereby improving physical properties such as strength.

If the crystallization constant (Oc) is less than 60, the degree of crystallinity may be lowered or Young's modulus may be lowered.

The washing and drying step removes moisture contained in the meta-aramid fibers from which the polar amide-based solvent has been removed through water washing and water washing of the fiberized meta-aramid fibers to remove the polar amide-based solvent contained in the meta-aramid fibers. This is the drying step.

The washing and drying steps may be performed in the same manner as for meta-arimid fiber through general wet spinning.

The hot stretching step is a step of hot stretching the dried meta-aramid fiber at 250 to 350°C, and the meta-aramid fiber is stretched through a hot stretching roller.

After the heat stretching step, the heat setting step, crimp application step, etc. can be additionally performed and can be performed in the same manner as the general method of manufacturing meta-aramid fiber.

The method for manufacturing meta-aramid fibers with improved physical properties of the present invention as described above includes coagulant temperature (°C), dope temperature (°C), draw ratio, coagulant concentration (% by weight), and spinning speed (m/m) in the spinning and stretching stages. min), the physical properties of meta-aramid fibers can be improved.

The meta-aramid fiber of the present invention manufactured by the manufacturing method described above satisfies the following equation (2).

Equation (2) OD + YM ≥ 120

However, OD: crystallinity (%), YM: Young's modulus (g/de)

The meta-aramid fiber produced by the meta-aramid fiber production method of the present invention is the sum of crystallinity (OD) and Young's modulus (YM) as shown in Equation (2) above. This will be over 120.

In more detail, the meta-aramid fiber produced by the manufacturing method of the present invention has a high crystallinity degree (OD) of 80% or more and has excellent physical properties with a Young's modulus (YM) of 40 g/de or more.

In addition, since the strength is improved due to the high crystallinity and Young's modulus as described above, it is preferable that the meta-aramid fiber according to the present invention has a strength of 4.6 g/de or more.

The meta-aramid fiber with improved physical properties of the present invention has excellent physical properties and can be used for various purposes by improving the physical properties of products such as fabric, paper, and non-woven fabrics manufactured using the meta-aramid fiber of the present invention.

Hereinafter, examples of a method for manufacturing meta-aramid fibers with improved physical properties according to the present invention are shown, but these examples are provided only to understand the content of the present invention, and the scope of the present invention is necessarily limited to these examples. It should not be interpreted as such.

Examples 1 to 8

Meta-aramid polymerized with meta-phenylene diamine (MPD) and isophthaloyl chloride (IPC) is dissolved in the solvent dimethylacetamide (DMAc) to produce meta-aramid with a meta-aramid concentration of 20% by weight. Dope was formed.

The meta-aramid dope was wet-spun in a coagulation bath to form meta-aramid fibers, then stretched, washed, and dried.

The dried meta-aramid fibers were hot-stretched at 250-350°C and heat-set at 300-450°C to prepare meta-aramid fibers with improved physical properties according to the present invention.

In each example, the coagulant temperature (℃), dope temperature (℃), stretching ratio, coagulant concentration (% by weight), and spinning speed (m/min) were used so that the crystallization constant (Oc) according to equation (1) was 60 or more. was adjusted and is shown in Table 1.

Comparative Examples 1 to 3

It was prepared in the same manner as Example 1, but the crystallization constant (Oc) was adjusted to be less than 60, and the coagulant temperature (°C), dope temperature (°C), draw ratio, coagulant concentration (% by weight), and spinning speed ( m/min) is shown in Table 2.

◈ Physical property evaluation

The strength, nodulation degree, and Young's modulus of Examples 1 to 8 and Comparative Examples 1 to 3 were measured and are shown in Table 1 for Examples and Table 2 for Comparative Examples. (Comparative Example 4 is a meta-aramid fiber from US company D, and Comparative Example 5 is a meta-aramid fiber from Chinese company Y)

In addition, meta-aramid fibrid was prepared from the meta-aramid dopro of the above example, and the meta-aramid fibers of Examples 1 to 8 and Comparative Examples 1 to 5 were used as flocs, and the fibrid and floc were mixed at a weight ratio of 1:1. It was mixed and manufactured into paper with a basis weight of about 40 g/m2, and the tensile strength of the manufactured paper was measured and shown in Table 1 for examples and Table 2 for comparative examples.

* measurement method

1. Crystallinity: Using XRD (PW 1700, Philips, After setting the background in the angle (2θ) range, the degree of cohesion is measured using the XRD device.

2. Fiber strength: Measure the fineness with Vibroskop, Lenzing's analysis equipment, enter the fineness into Vibrodyn and measure the strength.

3. Young's modulus (initial elastic modulus): Ratio of elongation and load at the beginning of fiber elongation = strength/elongation. The measurement method is to measure fineness with Vibroskop, Lenzing's analysis equipment, enter the fineness into Vibrodyn, and then calculate the strength. /Measure elongation. At this time, the ratio of elongation and load (strength/elongation) at the initial stage of fiber elongation (2%) is measured as Young's modulus.

4. Paper tensile strength: Measured using L&W's Tensile Tester according to ASTM D 828 measurement method. This measures the force when the paper breaks by applying tension in the MD direction.

division Example One 2 3 4 5 6 7 8 Coagulant temperature (Ct, ℃) 40 40 40 40 30 20 15 15 Dope temperature (Dt, ℃) 80 70 70 70 70 70 70 70 Elongation multiple (Dr) 3 4 3 3 3 3 3 4 Coagulant solvent concentration
(Cc, weight%) 40 40 50 40 40 40 40 40 Radiation speed (V, m/min) 4 4 4 3.5 4 4 4 4 Crystallization constant (Oc) 60 70 65.6 60 70 105 140 186.7 Fiber strength (g/de) 4.61 5.40 5.06 4.63 5.40 5.76 5.88 5.92 Crystallinity (OD, %) 80.8 85.7 83.3 81.9 86.6 85.7 88.6 90.3 Young's modulus (YM,g/de) 42.4 49.3 46.3 51.4 49.0 52.9 52.5 56.2 Paper tensile strength (N/cm) 36.5 37.1 36.1 38.5 36.9 38.4 39.0 41.2

division Comparative example One 2 3 4 5 Coagulant temperature (Ct, ℃) 40 40 50 - - Dope temperature (Dt, ℃) 70 50 70 - - Elongation multiple (Dr) 3 3 4 - - Coagulant solvent concentration
(Cc, weight%) 40 40 40 - - Radiation speed (V, m/min) 4 4 4 - - Crystallization constant (Oc) 52.5 37.5 56 - - Fiber strength (g/de) 4.50 4.30 4.55 4.72 4.52 Crystallinity (OD, %) 72.8 70.2 75.4 74.5 72.1 Young's modulus (YM,g/de) 30.5 31.9 33.3 37.2 32.5 Paper tensile strength (N/cm) 35.7 34.7 33.5 33 34.9

As shown in Tables 1 and 2, Examples 1 to 8, which are meta-aramid fibers manufactured by a meta-aramid fiber manufacturing method with improved physical properties, have a crystallization constant (Oc) of 60 or more, a crystallinity degree of 80% or more, and a Young's modulus of 40 g/de. From the above, it can be seen that all physical properties are superior to Comparative Examples 1 to 3, and the sum of crystallinity and Young's modulus is 120 or more.

In addition, it can be seen that the strength of the meta-aramid fibers in Examples 1 to 8 is more than 4.61 g/de, which is superior to Comparative Examples 1 to 5.

As described above, when the crystallization constant (Oc) is manufactured to be 60 or more, the physical properties of the meta-aramid fiber can be improved without the need for functional materials or additional processes.

In addition, it can be seen that the paper manufactured with the meta-aramid fibers of Examples 1 to 8 had a tensile strength of 36 N/cm or more, which was higher than that of the paper containing the meta-aramid fibers of Comparative Examples 1 to 5. In other words, when the meta-aramid fiber of the present invention is contained in textile products such as paper, fabric, and non-woven fabric, the physical properties of the textile product can be improved.

Claims (4)

In meta-aramid fibers formed by wet spinning meta-aramid polymerized with meta-phenylene diamine (MPD) and isophthaloyl chloride (IPC),
The meta-aramid fiber has a crystallinity (%) of 80% or more and satisfies the following equation (2).
Equation (2) OD + YM ≥ 120
However, OD: crystallinity (%), YM: Young's modulus (g/de)
delete According to paragraph 1,
The meta-aramid fiber is a meta-aramid fiber with improved physical properties, characterized in that the Young's modulus is 40 g/de or more.
According to paragraph 1,
The meta-aramid fiber is a meta-aramid fiber with improved physical properties, characterized in that the strength is more than 4.6 g/de.