KR20170036990A - Method of manufacturing aramid fiber with low denier - Google Patents

Abstract

When an aramid fiber is manufactured by a spinning dope in which an aramid polymer is dissolved in a sulfuric acid solvent being spun through a spinneret, coagulated with a coagulation liquid, and then washed and dried, (i) the liquer ratio of the coagulation liquid is adjusted to 1:30 to 1:43 for the spinning dope, (ii) a halved spinneret is used in which two spinning hole formation regions (X) where spinning holes are formed by the spinneret are divided by one embossing-processed separation region (Z), and (iii) two strands of the aramid fiber are combined with each other and pass through one yarn guide during the washing and drying of the coagulated aramid fiber. According to the present invention, workability can be significantly improved because of effective prevention of yarn winding in a spinning roller or a spinneret discharge error that is attributable to a decline in spinning dope transport speed and staying of the spinning dope in the spinneret for an extended period of time during the manufacturing of the fine-denier aramid fiber. In addition, the present invention is capable of effectively preventing a decline in aramid fiber strength (yarn weakening) because excessive aramid fiber coagulation is prevented and the length of time during which the spinning dope stays in the spinneret is reduced in the early stage of the coagulation. Furthermore, the present invention is capable of improving productivity because the two strands of the coagulated aramid fiber are combined with each other during the washing and drying, the strands pass through the one yarn guide, and then the strands are divided.

Description

TECHNICAL FIELD The present invention relates to a method for manufacturing aramid fibers,

The present invention relates to a method for producing three-fiber aramid fibers, and more particularly, to a method for manufacturing aramid yarns by shortening the time during which the yarn dope remains in the spinneret and effectively preventing the aramid yarn from being excessively coagulated at the initial stage of the coagulation process, The present invention relates to a method for producing an aramid fiber, which comprises the steps of: (1) preparing an aramid fiber; (2) The present invention also relates to a method for producing aramid fibers.

The aramid fibers include para-aramid fibers and meta-aramid fibers. Among them, para-aramid fiber has excellent properties such as high strength, high elasticity and low shrinkage. Especially, it has a strong strength enough to lift a 2-tonne automobile by a thin thread having a thickness of about 5 mm, It has been used in a variety of applications in high-tech industries such as aerospace.

The aramid fibers are typically produced by a process comprising the steps of (i) spinning an aramid spinning dope through a spinneret 20, (ii) spinning the irradiated aramid fibers into a coagulation bath 30 and a coagulating solution (Iii) washing and neutralizing the coagulated aramid fibers while sequentially passing over the at least one water wash rollers 50 and, if necessary, the neutralization rollers 60, and (Iv) drying the washed and neutralized aramid fibers with the drying device 70, and winding the wound aramid fibers on the winding roller 80 in this order.

For example, as disclosed in Korean Patent No. 10-0910537, an aromatic diamine such as paraphenylenediamine is dissolved in an organic solvent to which an inorganic salt has been added to form an aramid spinning dope, And an aromatic diacid halide such as terephthaloyl dichloride is added to the mixed solution. To prepare an aramid polymer, and then the prepared aramid polymer was dissolved in sulfuric acid to prepare a radiation dope.

Examples of the organic solvent include N-methyl-2-pyrrolidone (NMP), N, N'-dimethylacetamide (DMAc), hexamethylphosphoramide (HMPA) Methyl urea (TMU), N, N-dimethylformamide (DMF) or mixtures thereof may be used. As the inorganic salt, CaCl2, LiCl, NaCl, KCl, LiBr, KBr, or a mixture thereof may be used.

The aromatic diamine may be para-phenylenediamine, 4,4'-diaminobiphenyl, 2,6-naphthalenediamine, 1,5-naphthalenediamine, or 4,4'-diaminobenzanilide.

The aromatic diacid halide may be terephthaloyl dichloride, 4,4'-benzoyl dichloride, 2,6-naphthalene dicarboxylic acid dichloride, or 1,5-naphthalene dicarboxylic acid dichloride.

The aramid polymer may be selected from the group consisting of polyparaphenylene terephthalamide (PPD-T), poly (4,4'-benzanilide terephthalamide), poly (paraphenylene-4 , 4'-biphenylene-dicarboxylic acid amide), or poly (paraphenylene-2,6-naphthalene dicarboxylic acid amide).

The conventional method of producing three-fiber filament yarn is not to emboss two of the radiation-hole-forming regions X in which the radiation holes are formed as shown in Fig. 2, so that one separation A radial dope containing an aramid polymer dissolved in a sulfuric acid solvent is radiated through a two-part spinneret having a structure separated by a zone (Y), and then the radiated aramid fiber is solidified as a coagulating solution, Finely divided aramid.

At this time, when the liquid amount ratio of the radial dope: coagulating liquid was adjusted to 1:45 or more, and the coagulated aramid fiber was washed and dried, one strand of aramid fiber was passed through one apostrophe.

However, in the case of producing the three-fiber aramid fiber by the above-described conventional method, the feeding speed of the spinning dope is slowed and the spinning dope stays in the spinning nozzle for a long time in the spinning zone, Or the yarn curling phenomenon occurs in the spinning roller, resulting in a problem that yarn (pharmacist) having poor physical properties and poor operability is generated.

In addition, the above-mentioned conventional method has a problem that a yarn (pharmacist) having a weak physical property is generated because of excessively solidifying the aramid fiber in the initial stage of the coagulation of the irradiated aramid fiber due to too much liquid ratio of the spinning dope: coagulating solution.

In addition, in the above-described conventional method, one strand of aramid fibers of three sizes in the washing and drying steps is passed through a single sheet of the wash rollers and the drying rollers, thereby lowering the productivity.

These problems are caused by the fact that when the three-fiber aramid yarn is manufactured, the retention time of the spinning dope in the spinneret becomes relatively long due to the decrease in the spinning speed of the spinning dope and the productivity is lowered due to the decrease in the spinning dope discharge amount per hour.

The object of the present invention is to provide a method for producing a three-fineness aramid yarn with excellent productivity and productivity while effectively preventing generation of yarn (pharmacist) having weak physical properties.

In order to achieve the above object, in the present invention, when the aramid fiber is produced by spinning a radial dope containing an aramid polymer dissolved in a sulfuric acid solvent through a spinneret, solidifying it with a coagulating liquid, (2) a radiation zone (X) in which the radiation holes are formed by the spinneret is embossed to form a separation zone (Z) 1 (Iii) when the coagulated aramid fibers are washed and dried, two strands of aramid fibers are combined and passed through one apostrophe.

Disclosure of Invention Technical Problem [10] The present invention relates to a method for producing aramid fibers of three filaments, in which the delivery speed of the radial dope is slowed and the time during which the radial dope is retained in the spinneret becomes long to effectively prevent discharge failure in the spinneret or yarn curling in the spinning roller So that the operability can be greatly improved. In addition, the present invention can prevent a phenomenon that the aramid yarn becomes excessively solidified at the initial stage of solidification, and shorten the time during which the radial dope is retained in the spinneret, thereby effectively preventing the phenomenon that the strength of the aramid fiber is lowered .

In addition, the present invention can improve the productivity by combining two strands of solidified aramid fibers in a washing and drying process, passing them through one apostrophe, and splitting them.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a schematic view of a process for producing aramid fibers.
2 is a schematic cross-sectional view of a conventional spinneret used in the manufacture of three filamentary aramid fibers.
Fig. 3 is a schematic view of a spinneret cross section used for producing three-fiber aramid fibers according to the present invention. Fig.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

As shown in FIG. 1, when the aramid fiber is produced by spinning a radial dope containing an aramid polymer dissolved in a sulfuric acid solvent through a spinneret, solidifying it as a coagulating solution, washing and drying the aramid fiber, (Ii) one of the spinning hole forming zones (X) in which the spinning holes are formed by the spinneret is embossed in the separation zone (Z), and , And (iii) when the coagulated aramid fiber is washed and dried, two strands of the aramid fiber are combined and passed through one apostrophe.

Specifically, the present invention produces a radial dope wherein the aramid polymer is dissolved in a sulfuric acid solvent.

As an embodiment, an aromatic diamine such as paraphenylenediamine is dissolved in an organic solvent to which an inorganic salt is added to prepare a mixed solution, and an aromatic diacid halide such as terephthaloyldichloride is added to the mixed solution. To prepare an aramid polymer, and then the prepared aramid polymer was dissolved in sulfuric acid to prepare a radiation dope.

Examples of the organic solvent include N-methyl-2-pyrrolidone (NMP), N, N'-dimethylacetamide (DMAc), hexamethylphosphoramide (HMPA) Methyl urea (TMU), N, N-dimethylformamide (DMF) or mixtures thereof may be used. As the inorganic salt, CaCl2, LiCl, NaCl, KCl, LiBr, KBr, or a mixture thereof may be used.

The aromatic diamine may be para-phenylenediamine, 4,4'-diaminobiphenyl, 2,6-naphthalenediamine, 1,5-naphthalenediamine, or 4,4'-diaminobenzanilide.

The aromatic diacid halide may be terephthaloyl dichloride, 4,4'-benzoyl dichloride, 2,6-naphthalene dicarboxylic acid dichloride, or 1,5-naphthalene dicarboxylic acid dichloride.

The aramid polymer may be selected from the group consisting of polyparaphenylene terephthalamide (PPD-T), poly (4,4'-benzanilide terephthalamide), poly (paraphenylene-4 , 4'-biphenylene-dicarboxylic acid amide), or poly (paraphenylene-2,6-naphthalene dicarboxylic acid amide).

Next, as shown in FIG. 3, two spinneret forming zones (X) in which spinner holes are formed in the spinneret are separated by one embossed separation zone (Z) Radiation dope is emitted.

Each of the two radiation hole forming regions X formed with the radiation holes in the spinneret preferably has a half-moon shape.

Since the present invention uses the two-part spinneret shown in Fig. 3, in which the two spinneret-forming zones X are separated by one embossed separation zone Z, the spinneret 20 In particular, it is possible to shorten the time of staying in the separation zone (Z) to effectively prevent the discharge failure in the spinneret and the yarn curling phenomenon in the spinning roller from occurring, thereby greatly improving the operability and, at the same time, (Hereinafter referred to as "pharmacist").

Next, the aramid fibers radiated through the spinneret 20 are solidified as a coagulating solution. In this case, in the present invention, the liquid amount ratio of the spinning dope / coagulating liquid is adjusted to 1:30 to 1:43 to prevent excessive clotting of the aramid fibers at the initial stage of solidification.

When the liquid dose ratio of the radiant dope: coagulating liquid is out of the above-mentioned range, the aramid fiber may solidify excessively or too small at the initial stage of solidification, and pharmacopoeia may be generated.

As an example of the coagulation step, as shown in FIG. 1, the irradiated aramid fibers are injected into a coagulation tube 40 having a coagulation bath 30 containing a coagulating solution and a coagulating solution injection opening 41 for injecting coagulating solution Let it pass through the coagulating solution in turn.

Next, when the coagulated aramid fiber is washed and dried, two aramid fibers are combined and passed through one apostrophe to produce three-fiber aramid fibers with high productivity.

As an implementation example, when the coagulated aramid fiber is washed and dried, two aramid fibers are combined and passed through a single apostrophe, and then two strands of the combined aramid fibers are dispersed and then wound on a winding roller. Alternatively, The two fibers may be rewound while splitting the two aramid fibers wound in a combined state using a rewinder after winding the two fibers on the winding roller without splitting.

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

However, the scope of protection of the present invention should not be construed as being limited only by the following 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 para-phenylenediamine was dissolved in the reactor to prepare a mixed solution.

Next, the mixed solution was charged with equimolarly adding terephthaloyl dichloride of the same molar amount as that of the para-phenylenediamine and reacted to prepare a para-aramid polymerization agent, and then the para-aramid polymerization agent Was dissolved in concentrated sulfuric acid to prepare spinning dope.

Next, as shown in FIG. 1, the radiation dope is separated by one embossed separation zone (Z) in which two radiation hole forming zones (X) in which the radiation holes are formed in the spinneret are separated And then passed through an air gap having a distance of 8 mm and then passed through a coagulation bath 30 containing a coagulating solution and a coagulation tube 40 through which a coagulating solution is injected And solidified.

At this time, the liquid amount ratio of the radial dope: coagulating liquid was adjusted to 1:30, and the flow rate of the coagulating liquid was adjusted to 420 L / hour.

Next, the two aramid fibers thus coagulated are combined and washed with water while passing them through one of the wash rollers (50, 60) and a drying device (drying roller: 70), and then the combined aramid fibers 2 Strand was fibrillated by one strand and wound around a winding roller 80 at a winding speed of 750 m / min to produce a three-fineness aramid fiber of 200 denier.

Table 1 shows the results of evaluating the physical properties and operational properties (yield) of the three-fiber-modified aramid fibers.

Comparative Example  One

As the spinneret for spinning the spinning dope, two spinneret-forming zones (X) in which spinner holes are formed are not embossed as shown in FIG. 2, A three-fineness aramid fiber of 200 denier was prepared in the same manner as in Example 1, except that a two-part spinneret separated by one yarn (Y) was used.

Table 1 shows the results of evaluating the physical properties and operational properties (yield) of the three-fiber-modified aramid fibers.

Comparative Example  2

A spinning nozzle for spinning the spinning dope and having a spinning hole formed on the entire bottom of the spinning spinneret; a spinning speed of 500 m / min; a spinning fluid flow rate of 650 L / Dodeca-aramid fiber of 200 denier was prepared in the same manner as in Example 1, except that the liquid to liquid ratio of the dope: coagulated liquid was changed to 1: 174.

Table 1 shows the results of evaluating the physical properties and operational properties (yield) of the three-fiber-modified aramid fibers.

Comparative Example  3

Except that two strands of the coagulated aramid fiber were passed through one apostrophe instead of one strand of aramid fiber being passed through one apostrophe in the wash and dry process, Finely divided aramid fibers.

Table 1 shows the results of evaluating the physical properties and operational properties (yield) of the three-fiber-modified aramid fibers.

division Fiber strength (g / d) Fiber elongation (%) Workability (Yield:%) Example 1 23.8 2.8 97 Comparative Example 1 23.8 2.8 85 Comparative Example 2 22.0 2.7 40 Comparative Example 3 24.0 2.8 41

The fiber strength and fiber elongation in Table 1 were evaluated in the following manner.

Intensity (g / d) and elongation ( % )

The tensile properties of the aramid fibers were measured according to the ASTM D885 test method. Specifically, the physical properties of the fibers were determined by stretching until the copolymerized aramid fibers having a length of 25 cm were broken in an Instron Tester (Instron Engineering Corp., Canton, Mass).

At this time, the tensile speed was 25 mm / min, and the initial load was 1/130 g of fineness. The number of samples was determined by the average value after testing five samples. The strength was obtained from the maximum load at break, and the elongation was obtained from the length at break.

10: Extruder 20: spinning detention
30: Coagulation tank 40: Coagulation tube
41: Coagulating nozzle Y: Aramid fiber
50, 60: Wash rollers 70: Drying apparatus
80: Winding roller

Claims (4)

A method for producing an aramid fiber, comprising the steps of: (i) irradiating a radiant dope containing an aramid polymer dissolved in a sulfuric acid solvent through a spinneret, solidifying it with a coagulating liquid, : 30 to 1: 43, and (ii) two spinneret forming zones (X) in which the spinneret holes are formed by the spinneret are separated by one embossing zone (Z) , And (iii) when the coagulated aramid fibers are washed and dried, two aramid fibers are combined and passed through one apostrophe. The method according to claim 1, characterized in that two aramid fibers coagulated at the time of washing with water and drying are combined and passed through a single apostrophe, and then two stranded aramid fibers are dispersed and wound up on a winding roller A method for producing an aramid fiber. The method according to claim 1, wherein two aramid fibers coagulated at the time of washing with water and dried are combined and passed through a single apical pole, then wound on a winding roller, and then spliced with two strands of aramid fibers merged with a rewinder And then winding up the filaments. The method of claim 1, wherein the spinneret-forming zone (X) in which spinner holes are formed in the spinneret is half-moon-shaped.

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