KR20180072052A - Method of manufacturing para-aramid fiber - Google Patents

Abstract

The present invention relates to a method for manufacturing a para-aramid fiber, comprising the following steps of: preparing polymerization solution including an aramid polymer by adding terephthaloyl dichloride to an organic solvent in which a cyano-para-phenylene diamine is dissolved and conducting reaction thereof; primarily coagulating a spun fiber while passing the spun fiber into a primary coagulation tank (30) and a coagulation tube (40) positioned directly under a spinneret when manufacturing a para-aramid by spinning, coagulating, washing, neutralizing, and drying the polymerization solution; and secondarily coagulating the fiber primarily coagulated while passing the same into a secondary coagulation tank (50) positioned in front of a washing roller (60) and manufacturing a para-aramid fiber by washing, neutralizing and drying the secondarily coagulated fiber. According to the present invention, it is possible to improve crystallinity of a fiber by controlling a crystallization time of the fiber through a primary coagulation process and a secondary coagulation process before washing a spun fiber, thereby greatly improving the strength and physical properties of the para-aramid fiber manufactured by the present invention.

Description

FIELD OF THE INVENTION The present invention relates to a para-aramid fiber,

The present invention relates to a method for producing para aramid fibers, and more particularly, to a method for producing aramid fibers capable of improving the strength and physical properties of fibers by improving the degree of crystallization of fibers when coagulating spun aramid fibers.

Para-aramid fibers have excellent properties such as high strength, high elasticity and low shrinkage. In particular, they have a strength of about 5mm and a thickness of about 2 tons, which is strong enough to lift a car, It is used for various purposes in high-tech industries such as the field.

The para-aramid fibers are typically produced by a process comprising the steps of: (i) spinning an aramid radiation dope through a spinneret 20; and (ii) spinning the irradiated aramid fiber under the spinneret (Iii) a step of passing the coagulated aramid fiber through the at least one water wash roller 60 while passing through the at least one water wash roller 60 in succession, and (Iv) a neutralization step in which the washed aramid fibers are neutralized while passing over the neutralization rollers 70, and (v) the drying steps in which the neutralized aramid fibers are dried while being passed over the drying rollers 8 have.

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 is added to prepare an aramid radiation dope, A solution is prepared, and an aromatic diacid halide such as terephthaloyl dichloride or the like 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.

As an example of another method of producing the aramid radiation dope, there is disclosed an organic solvent in which paraphenylenediamine and cyano-para-phenylenediamine are dissolved in an organic solvent as disclosed in Korean Patent No. 10-171994 Terephthaloyldichloride was added and reacted to prepare a radiation dope containing a copolymerized aramid polymer containing an aromatic group substituted with a cyano group (-CN). In this case, the copolymerized aramid polymer can be advantageously prepared as a radiation dope without a process of dissolving the copolymerized aramid polymer in sulfuric acid.

However, when the aramid fibers spun in the same manner as the above-described conventional method are coagulated while passing through the primary coagulation bath 30 and the coagulation tube 40 positioned immediately under the spinneret, only the surface of the spun fiber is washed The crystallization time of the fiber is controlled during the coagulation step so that the degree of crystallization of the fiber is not effectively improved and the degree of crystallization of the fiber is lowered due to the water washing process, .

The present invention provides a method for producing para-aramid fibers, which can improve the strength and physical properties of the para-aramid fibers produced by adjusting the crystallization time of the fibers when the radiated para-aramid fibers are coagulated to improve the degree of crystallization of the fibers .

In order to solve such a problem, in the present invention, terephthaloyl dichloride is added to an organic solvent in which cyano-para-phenylenediamine is dissolved and reacted to prepare a polymerization solution containing an aramid polymer, When the para-aramid is produced by spinning, coagulating, washing, neutralizing and drying the solution, the spun fibers are first coagulated while passing through the primary coagulation bath 30 and the coagulation tube 40 positioned immediately under the spinneret, The first coagulated fiber is passed through a secondary coagulation bath 50 located in front of the water wash roller 60, and then the water is washed, neutralized and dried to produce para-aramid fiber.

The present invention can improve the degree of crystallization of the fibers by controlling the crystallization time of the fibers through the primary coagulation process and the secondary coagulation process before washing the spun fibers. As a result, the para-aramid fiber produced by the present invention has greatly improved strength and physical properties.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic view of a process for producing para-aramid fibers according to a conventional method; FIG.
2 is a schematic view of a process for producing para-aramid fibers according to the present invention.

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

2, a terephthaloyl dichloride is added to an organic solvent in which cyano-para-phenylenediamine is dissolved and reacted to prepare a polymerization solution containing an aramid polymer, The radioactive fibers are first coagulated while passing through the primary coagulation bath 30 and the coagulation tube 40 located immediately under the spinneret, and then the solution is cooled to a temperature of 1 < RTI ID = 0.0 > And solidifying the fibers by passing them through the secondary coagulation bath 50 located in front of the water wash rollers 60, followed by secondary coagulation, washing, neutralization and drying.

Para-phenylenediamine may be dissolved in the organic solvent together with cyano-para-phenylenediamine, and a neutralizing agent such as lithium carbonate, calcium oxide and the like may be further dissolved.

It is preferable that the second coagulation bath 50 is a multi-stage coagulation bath in which two to five coagulation baths, that is, one-stage coagulation bath to five-stage coagulation bath, are arranged in order.

When the secondary coagulation tank 50 is in the form of a multi-stage coagulation bath, the temperature of the coagulation bath contained in the coagulation baths from the first coagulation bath forming the second coagulation bath 50 toward the final coagulation bath Is set to gradually increase and the concentration of the solvent contained in the coagulation baths is gradually lowered is preferable to improve the degree of crystallization of the fibers by controlling the crystallization time of the fibers during the coagulation process.

As the solvent contained in the coagulating solution, it is preferable to use a solvent which is the same as the organic solvent used in the production of the polymerization solution containing the aramid polymer.

Next, an implementation example of the present invention will be described.

First, the present invention carries out the step of producing a radiation dope for producing para-aramid fibers. Specifically, after adding a neutralizing agent to an organic solvent to prepare a polymerization solvent, the organic solvent may be prepared by dissolving paraphenylenediamine and cyano-para-phenylenediamine together or dissolving cyano-para-phenylenediamine alone , And then a small amount of terephthaloyldichloride is added to the mixed solution while stirring the mixed solution to perform a primary polymerization to form a prepolymer in the polymerization solvent.

Then, terephthaloyldichloride is further added to the polymerization solvent to carry out a secondary polymerization to obtain a polymerization solution for producing an aramid in which a copolymerized aramid copolymer containing an aromatic group substituted with a cyano group (-CN) is dissolved in an organic solvent Dough).

N, N'-dimethylacetamide (DMAc), hexamethylphosphoramide (HMPA), N, N, N ', N' -Tetramethylurea (TMU), N, N-dimethylformamide (DMF) or mixtures thereof may be used. As the neutralizing agent, Li ₂ CO ₃ or CaCO ₃ may be used.

Next, as shown in FIG. 2, the radiation dope produced as described above is radiated through the spinneret 20, and the radiated para-aramid fibers are irradiated with the primary coagulation bath 30 and the coagulating solution And then the primary solidified fiber is passed through the secondary coagulation bath 50 located in front of the water wash roll 60 and is secondarily solidified and then solidified And passed through the water wash rollers 60, the neutralizing rollers 70 and the drying rollers 90, and washed, neutralized and dried to prepare para-aramid fibers.

At this time, as the secondary coagulation tank 50, a three-stage coagulation tank composed of three coagulation tanks can be used.

The present invention can improve the degree of crystallization of the fibers by controlling the crystallization time of the fibers through the primary coagulation process and the secondary coagulation process before washing the spun fibers. As a result, the para-aramid fiber produced by the present invention has greatly improved strength and physical properties.

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

However, the following embodiments are merely preferred embodiments of the present invention, and should not be construed as limiting the scope of protection of the present invention.

Example 1

1,700 g of N, N'-dimethylacetamide (DMAC) was placed in a reactor in a nitrogen atmosphere, and then 110 g of cyano-para-phenylenediamine was added to the reactor to prepare a mixed solution.

Subsequently, 250 g of terephthaloyl dichloride was added to the reactor containing the mixed solution evenly over twice, and 90 g of a neutralizing agent lithium carbonate was added to prepare a polymerization solution (radial rope) containing a para-aramid polymer.

Next, as shown in FIG. 2, the polymer solution is radiated through the spinneret 20, the spinning fibers are sequentially passed through the coagulation tube 40 into which the primary coagulation bath 30 and the coagulating solution are injected The primary coagulated fiber is then subjected to secondary coagulation while passing through the secondary coagulation bath 50 located at the front of the water wash roller 60 and is then solidified by the water wash rollers 60 and the neutralizing rollers 70, Followed by washing with water, neutralization, and drying while sequentially passing through the rollers 80 to produce para-aramid fibers.

The temperature of the coagulation solution in the first stage coagulation bath was set at 0 ° C, and the concentration of the polymerization solvent in the coagulation solution The concentration of the coagulating solution in the two-stage coagulating bath was 10 ° C, the concentration of the polymerization solvent in the coagulating solution was 15 wt%, the temperature of the coagulating solution in the three-stage coagulating bath was 20 ° C, The concentration was 5 wt%.

The strength and crystallinity of the produced para-aramid fiber were measured and the results are shown in Table 1.

Example  2

N-N'-dimethylacetamide (DMAC) was introduced into a reactor in a nitrogen atmosphere, and then 90 g of cyano-para-phenylenediamine and 40 g of para-phenylenediamine were added to the reactor and dissolved. .

Next, 250 g of terephthaloyl dichloride was added to the reactor containing the mixed solution evenly twice, and at the same time, 95 g of a neutralizing agent calcium oxide was added to prepare a polymerization solution (radial rope) containing the para-aramid polymer.

Next, as shown in FIG. 2, the polymer solution is radiated through the spinneret 20, the spinning fibers are sequentially passed through the coagulation tube 40 into which the primary coagulation bath 30 and the coagulating solution are injected The primary coagulated fiber is passed through the secondary coagulation tank 50 located in front of the water wash roller 60 and is secondarily solidified and then the water wash roller 60, neutralizing roller 70 and drying roller 80) in this order, washed, neutralized, and dried to produce para-aramid fibers.

The temperature of the coagulation solution in the first stage coagulation bath was set at 0 ° C, and the concentration of the polymerization solvent in the coagulation solution The concentration of the coagulating solution in the two-stage coagulating bath was 10 ° C, the concentration of the polymerization solvent in the coagulating solution was 15 wt%, the temperature of the coagulating solution in the three-stage coagulating bath was 20 ° C, The concentration was 5 wt%.

The strength and crystallinity of the produced para-aramid fiber were measured and the results are shown in Table 1.

Comparative Example  One

1,700 g of N, N'-dimethylacetamide (DMAC) was placed in a reactor in a nitrogen atmosphere, and then 110 g of cyano-para-phenylenediamine was added to the reactor to prepare a mixed solution.

Next, 250 g of terephthaloyl dichloride was added to the reactor containing the mixed solution evenly twice, and 90 g of a neutralizing agent lithium carbonate was added thereto to prepare a polymerization solution (radial rope) containing the para-aramid polymer.

Next, as shown in FIG. 1, the polymer solution is radiated through the spinneret 20, the spinning fibers are sequentially passed through the coagulation tube 40 into which the primary coagulation bath 30 and the coagulation solution are injected Then, the coagulated fiber was washed, neutralized, and dried by passing through a water wash roller 60, a neutralization roller 70 and a drying roller 80 in this order, thereby producing a para-aramid fiber.

The strength and crystallinity of the produced para-aramid fiber were measured and the results are shown in Table 1.

Comparative Example  2

1,700 g of N, N'-dimethylacetamide (DMAC) was introduced into the reactor in a nitrogen atmosphere, followed by the addition of 90 g of cyano-para-phenylenediamine and 40 g of paraphenylenediamine to the reactor, Respectively.

Next, 250 g of terephthaloyl dichloride was added to the reactor containing the mixed solution evenly twice, and at the same time, 90 g of neutralizing agent calcium oxide was added to prepare a polymerization solution (radial rope) containing the para-aramid polymer.

Next, as shown in FIG. 1, the polymer solution is radiated through the spinneret 20, the spinning fibers are sequentially passed through the coagulation tube 40 into which the primary coagulation bath 30 and the coagulation solution are injected Then, the coagulated fiber was washed, neutralized, and dried by passing through a water wash roller 60, a neutralization roller 70 and a drying roller 80 in this order, thereby producing a para-aramid fiber.

The strength and crystallinity of the produced para-aramid fiber were measured and the results are shown in Table 1.

division Crystallinity (%) Strength (g / d) Example 1 68 22 Example 2 72 24 Comparative Example 1 55 19 Comparative Example 2 52 21

The crystallinity and strength of Table 1 were evaluated by the following methods.

Crystallinity ( % )

The diffraction pattern obtained by X-ray analysis was used to determine the ratio of crystal peak to amorphous peak.

Strength (g / d)

The strength was measured according to ASTM D 885 test method.

Specifically, the maximum load at the time of fracture was determined by pulling until the para aramid fiber having a length of 25 cm was torn in an Instron tester (Instron Engineering Corp, Canton, Mass).

At this time, the tensile speed was 30 mm / min, and the initial load was 1/130 g.

The number of samples was determined by the average value after testing five samples.

10: Extruder 20: spinning detention
30: Primary coagulation tank 40: Coagulation tube
50: Secondary coagulation tank 60: Wash rollers
70: neutralization roller 80: drying roller
90: Coiling Roller Y: Spun Yarn

Claims (6)

Adding terephthaloyl dichloride to an organic solvent in which cyano-para-phenylenediamine is dissolved and reacting to prepare a polymerization solution containing an aramid polymer, and then spinning, coagulating, washing, neutralizing and drying the polymerization solution In the production of para-aramid,
After the spun fibers are firstly solidified while passing through the primary coagulation bath 30 and the coagulation tube 40 positioned immediately under the spinneret, the primary coagulated fibers are passed through the secondary coagulation < RTI ID = 0.0 > (50), followed by washing with water, neutralization and drying. The method according to claim 1, wherein para-phenylenediamine is also dissolved in the organic solvent together with cyano-para-phenylenediamine. The method of claim 1, wherein the secondary coagulation bath (50) is a multi-stage coagulation bath consisting of 2 to 5 coagulation baths. 4. The method according to claim 3, wherein the temperature of the coagulating solution contained in the coagulating baths gradually increases from the first coagulating bath forming the second coagulating bath (50) toward the last coagulating bath, A method for producing an aramid fiber. 4. The method according to claim 3, wherein the concentration of the polymerization solvent contained in the coagulation baths gradually decreases from the first coagulation bath forming the second coagulation bath to the final coagulation bath, ≪ / RTI > The method of claim 1, wherein the primary coagulation bath (30) is located at the lower end of the spinneret (15-30 mm) from the spinneret.

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