WO2019209009A1 - Method for stabilizing precursor fibers for manufacturing carbon fibers, and method for manufacturing carbon fibers by using same - Google Patents

Abstract

A method for manufacturing carbon fibers according to an embodiment of the present application comprises the steps of: preparing precursor fibers for manufacturing carbon fibers; and stabilizing the precursor fibers, the step of stabilizing the precursor fibers comprising a first stabilization step, a second stabilization step, a third stabilization step, and a fourth stabilization step, for which four different temperatures are set between the temperature at which heating is initiated according to a stabilization reaction of the precursor fibers and the temperature at which heating is maximized, wherein ozone gas is fed in at least one step of the third stabilization step and the fourth stabilization step.

Description

Stabilization method of precursor fiber for producing carbon fiber and method of manufacturing carbon fiber using same

[Citations with Related Applications]

The present invention claims the benefit of priority based on Korean Patent Application No. 10-2018-0049251 filed on April 27, 2018 and Korean Patent Application No. 10-2019-0046784 filed on April 22, 2019, All content disclosed in the literature is included as part of this specification.

[Technical Field]

The present application relates to a method for stabilizing precursor fibers for producing carbon fibers and a method for producing carbon fibers using the same.

Carbon fiber is an organic precursor in the form of fiber made from polyacrylonitrile (PAN), petroleum / coal hydrocarbon residue, Pitch or rayon, which is a carbonaceous carbon material having a mass content of carbon element of 90% or more. It means a fiber obtained by thermally decomposing a substance in an inert atmosphere.

Carbon fiber is lighter than steel and superior in strength, and is widely applied to various fields such as automobile, aerospace, wind power, and sports. For example, environmental regulations related to vehicle exhaust gas have recently been tightened due to environmental problems, and there is an increasing demand for high-efficiency lightweight cars.How to reduce the weight of a vehicle without sacrificing structural and mechanical strength As a result, techniques using carbon fiber reinforced composites have attracted attention.

In general, carbon fibers are manufactured through a stabilization process in which an oxidizing atmosphere is heated to oxidize and stabilize a precursor fiber, and a carbonization process in which the stabilized fibers are carbonized at a high temperature. Subsequently, a graphitization process may be subsequently performed. At this time, the precursor fibers of the carbon fibers include polyacrylonitrile (PAN), pitch, rayon, lignin, polyethylene, and the like. Among them, polyacrylonitrile (PAN) fiber has a high carbon yield and a high melting point of 50% or more, and is an optimal precursor for producing high performance carbon fiber compared to other precursors according to process condition control. Accordingly, most of the current carbon fibers are made from polyacrylonitrile fibers.

However, since carbon fiber has a high raw material price, undergoes various unit processes in the manufacturing process, and involves a long time heat treatment process, the final product forms an expensive price range, which limits its application and commercialization. Accordingly, the development of a technology that can mass-produce high performance carbon fiber at low cost is urgently required.

The present application is to provide a method for stabilizing the precursor fiber for producing carbon fiber and a method for producing carbon fiber using the same.

One embodiment of the present application,

Preparing precursor fibers for producing carbon fibers; And

Stabilizing the precursor fiber,

The stabilizing of the precursor fiber may include setting a first stabilization step, a second stabilization step, and a third temperature different from a temperature at which heat generation starts according to the stabilization reaction of the precursor fiber and a temperature at which the heat generation indicates a maximum. A stabilization step and a fourth stabilization step,

It provides a method for stabilizing the precursor fiber for producing carbon fiber to inject ozone gas when performing at least one of the third stabilization step and the fourth stabilization step.

In addition, another embodiment of the present application,

Preparing precursor fibers for producing carbon fibers stabilized by the method; And

Carbonizing the stabilized precursor fiber for producing carbon fibers

It provides a method for producing a carbon fiber comprising a.

According to an exemplary embodiment of the present application, by adding ozone gas in the step of stabilizing the precursor fiber for producing carbon fiber, it is possible to promote the stabilization reaction of the precursor fiber for producing carbon fiber, it is possible to secure the desired stabilization properties in a shorter time than conventional Can be.

In particular, according to an exemplary embodiment of the present application, by applying ozone gas when performing at least one of the third stabilization step and the fourth stabilization step, it is possible to achieve a desired level of stabilization in a short time.

In addition, according to an exemplary embodiment of the present application, by injecting ozone gas in the step of stabilizing the precursor fiber for producing carbon fiber, oxygen penetrates deep into the fiber due to the rapid diffusion rate of the active oxygen species generated by decomposition therefrom It is easy to alleviate the nonuniformity in a radial direction on a fiber cross section.

Hereinafter, the present application will be described in more detail.

In the present application, when a part "includes" a certain component, this means that it may further include other components, without excluding the other components unless otherwise stated.

In the carbon fiber manufacturing process using the precursor fiber for producing carbon fiber, before the high temperature carbonization process, a stabilization process of heat-treating the precursor fiber in an air atmosphere (oxygen) of 200 ℃ to 300 ℃ is essential. In this process, the fiber undergoes cyclization, oxidation and dehydrogenation, crosslinking reaction, and is flame resistant. Generally, the stabilization process requires a long time of 60 minutes to 120 minutes and is consumed accordingly. The energy is great. In addition, the longest time taken in the carbon fiber firing process, it plays an important role in determining the output of the final product. Therefore, from the economic point of view, the technology of reducing the stabilization process time is an important issue in the carbon fiber field.

Accordingly, the present inventors studied the stabilization process of the precursor fiber for producing carbon fiber, which can secure desired stabilization properties within a shorter time than before, and completed the present invention.

Carbon fiber manufacturing method according to an embodiment of the present application, preparing a precursor fiber for producing carbon fiber; And stabilizing the precursor fiber, wherein stabilizing the precursor fiber is set to four different temperatures between a temperature at which exothermic starts according to a stabilization reaction of the precursor fiber and a temperature at which exothermic is maximum. And a first stabilizing step, a second stabilizing step, a third stabilizing step, and a fourth stabilizing step, and injecting ozone gas when performing at least one of the third stabilizing step and the fourth stabilizing step.

In an exemplary embodiment of the present application, the precursor fiber for producing carbon fiber is not particularly limited as long as it can be made of carbon fiber through a carbonization process. More specifically, the precursor fibers for producing carbon fibers are polyacrylonitrile (PAN) -based fibers, pitch-based fibers, rayon-based fibers, lignin-based fibers, cellulose-based fibers, and polyethylene ( It may include one or more of the polyethylene-based fibers, but is not limited thereto.

The polyacrylonitrile (PAN) -based fiber refers to a polymer containing acrylonitrile as a main component, and has an advantage of manufacturing fibers having various performances through process changes compared to other fibers. In addition, in the case of the pitch (Pitch) -based fibers, since the properties are greatly changed depending on the type of precursor, it can be applied differently to the production of general purpose carbon fiber and high performance carbon fiber.

The polyacrylonitrile-based fibers are very expensive compared to general fibers. In general, carbon fibers account for 43% of the precursor fibers, 18% stabilization process, 13% carbonization process and 15% graphitization process. Therefore, the stabilization process as well as the low cost of the precursor fiber may be a key technology of the carbon fiber low cost technology. Since the stabilization process is a slower reaction than the carbonization process, the carbon fiber manufacturing process is the most energy consuming process.

The stabilization process is a process to make the molecular structure of the fiber more stable by the dehydrogenation reaction and the cyclization reaction by the reaction of oxygen and fiber, since the stabilization process using heat in the carbon fiber manufacturing process occupies most of the entire process time However, research is needed to reduce the stabilization process time.

In an exemplary embodiment of the present application, the stabilizing of the precursor fiber may be set to four different temperatures between a temperature at which heat generation starts according to the stabilization reaction of the precursor fibers and a temperature at which the heat generation indicates a maximum. And a stabilization step, a second stabilization step, a third stabilization step, and a fourth stabilization step, and injecting ozone gas when at least one of the third stabilization step and the fourth stabilization step is performed.

In the stabilization process of the precursor fiber for producing carbon fiber according to an exemplary embodiment of the present application, the temperature setting for each section is important in terms of productivity and quality. In general, if the stabilization process at a high temperature for a long time to reduce the heat damage to the fiber, but the process takes a long time, so to shorten the time to bring the process temperature high. However, if the temperature is excessively high in order to save time, fiber property degradation due to melting, burning, etc. may occur during the stabilization process.

Therefore, in an exemplary embodiment of the present application, in order to shorten the process time, after setting the maximum temperature and measuring the calorific value of each fiber temperature, the temperature is set to show the same heat generation in each of the stabilization and stabilization physical properties ( Typically density). Entering a high temperature region in a state where the reaction has not been sufficiently performed in the previous step, the micro-orientation of the fiber may be lowered due to local melting and solidification due to rapid heat generation. In addition, as the oxidation (dehydrogenation) reaction occurs in the stabilization process, the structure of the PAN is changed into a ladder polymer, and double bonds are formed between carbon and carbon, and thermal stability is enhanced. If you go to a high temperature without going through well, thermal stability may be reduced.

In one embodiment of the present application, the first stabilization step is set to a temperature within 45 ℃ from the temperature at which the heat generation according to the stabilization reaction of the precursor fiber, the second stabilization step to the fourth stabilization step, Based on the temperature set in the first stabilization step may be sequentially set to 5 ℃ to 45 ℃ high, it may be set to 5 ℃ to 15 ℃ high.

In one embodiment of the present application, the precursor fiber is a polyacrylonitrile (PAN) -based fiber, and stabilizing the precursor fiber, the first stabilization step is set to a temperature of 205 ℃ to 240 ℃, 220 It may include a second stabilization step set to a temperature of ℃ to 255 ℃, a third stabilization step set to a temperature of 235 ℃ to 265 ℃, and a fourth stabilization step set to a temperature of 250 ℃ to 280 ℃. At this time, the first stabilization step, the second stabilization step, the third stabilization step and the fourth stabilization step are set to different temperatures, respectively.

In an exemplary embodiment of the present application, preferably, ozone gas may be added when at least one of the third stabilization step and the fourth stabilization step is performed, and ozone gas may be added when the fourth stabilization step is performed. have.

When the ozone gas is added in the stabilization process, ozone is pyrolyzed at the process temperature, and various active oxygen species such as oxygen radicals, oxygen monoatoms, and oxygen diatoms are generated. The oxygen radicals have good reactivity due to low activation energy for chemical reactions, and thus easily participate in reaction with precursor fibers for producing carbon fibers to cause oxidation and dehydrogenation reactions. In the case of the oxygen atom has a high reactivity and diffusion rate, it is possible to penetrate deeply into the inner region of the fiber to react, which helps to solve the reactivity of the fiber diameter, oxygen distribution unevenness that can occur as the process time is reduced Can give

According to one embodiment of the present application, by injecting ozone gas in the step of stabilizing the precursor fiber for producing carbon fiber, it is possible to promote the stabilization reaction of the precursor fiber for producing carbon fiber, it is possible to secure the desired stabilization properties in a shorter time than conventional Can be. In particular, according to an exemplary embodiment of the present application, by applying ozone gas when performing at least one of the third stabilization step and the fourth stabilization step, it is possible to achieve a desired level of stabilization in a short time.

In one embodiment of the present application, the step of stabilizing the precursor fiber for producing carbon fiber may be performed in 60 minutes or less, it may be performed in 50 minutes or less. In addition, each of the first stabilization step to the fourth stabilization step may be independently performed in 15 minutes or less, may be performed in 13 minutes or less, or may be performed in 11 minutes or less. When the step of stabilizing the precursor fiber for carbon fiber production is performed for more than 60 minutes, the effect on productivity compared to the conventional process may be insignificant.

In an exemplary embodiment of the present application, the step of stabilizing the precursor fiber for producing carbon fiber may be performed in a batch type oven, or may be performed while the precursor fiber continuously passes through a plurality of ovens set to different temperatures. In addition, the oven may be a hot air oven having a good thermal insulation.

In the conventional stabilization process, using a hot air oven having a constant air flow therein, the heat treatment was performed for 60 to 120 minutes in an atmospheric atmosphere under conditions of good thermal insulation. However, in an exemplary embodiment of the present application, the ozone gas supplied from the ozone generator is introduced into the oven without heat treatment in an atmospheric atmosphere, and the rear end portion having a high temperature of the stabilization process is controlled by adjusting the input section of the ozone gas. By selectively putting in place, ozone gas is thermally decomposed and activated oxygen generated to improve stabilization properties compared to existing processes at the same time.

In one embodiment of the present application, the concentration of the ozone gas may be at least 450 ppm, at 450 ppm to 3,000 ppm, or at 550 ppm to 2,500 ppm at 15 ° C., of which 550 ppm to 2500 ppm are preferred. If the above-mentioned concentration is satisfied, not only the stabilization process is easily performed, but also the tensile strength, elasticity and elongation of the carbon fiber can be remarkably improved. When the concentration is less than the above-mentioned concentration, the stabilization property improvement effect due to the ozone gas input is insignificant, and when the concentration exceeds the above-mentioned concentration, the oxygen content in the stabilized fiber is excessively high, and oxygen and carbon are combined in the subsequent carbonization process. Proceeds to lower the carbon yield.

The ozone gas may be introduced from an ozone generator through a tube connected between the ozone generator and the oven in which the stabilization process is performed. The concentration of the ozone gas can be measured by OZM-7000GN equipment of Okirotec.

In addition, the carbon fiber manufacturing method according to an embodiment of the present application, preparing a precursor fiber for producing carbon fiber stabilized by the method; And carbonizing the stabilized precursor fiber for producing carbon fibers.

In one embodiment of the present application, the carbonizing step may use a method known in the art, and is not particularly limited. More specifically, the carbonizing step may be to carbonize the stabilized carbon fiber manufacturing fiber using thermal energy or microwave, but is not limited thereto.

The carbonization process may be performed in an inert atmosphere such as nitrogen through a high temperature carbonization furnace or the like. Maintaining an inert atmosphere such as nitrogen maintains an atmosphere such as nitrogen because other reactive gases enter and act as a large defect in carbonization due to unnecessary chemical reactions.

The temperature of the carbonization process may be 600 ° C. or higher. More specifically, the temperature may be 700 ℃ to 2,000 ℃, preferably 800 ℃ to 1,500 ℃. In the above temperature range, the precursor fiber for producing carbon fiber may be carbonized (hereinafter, carbonized). In this case, the carbonization process may be classified into low temperature carbonization and high temperature carbonization according to the difference in temperature during carbonization. The low temperature carbonization process may carbonize the precursor at a temperature of 600 ° C to 900 ° C, and the high temperature carbonization process may carbonize the precursor at a temperature of 1,000 ° C to 1,500 ° C.

Hereinafter, the exemplary embodiments described in the present application will be illustrated by examples. However, the following embodiments are not intended to limit the scope of the embodiments.

< Example  1>

<Step to stabilize>

Stabilization fiber was prepared by performing a stabilization process using 12K PAN fiber as a raw material.

Specifically, the screws were knotted on both sides of the fiber, cut into lengths of about 20 cm, and sandwiched between the die-shaped jigs (zig) so as to hang the weight for tension application. Thereafter, a weight of 1 kg was placed on a jig on both sides of the fiber combined with the fiber.

The stabilization process was carried out using a batch-type oven in which hot air blows from the rear to the front. The temperature conditions were set to 235 ° C. for the first stabilization step, 250 ° C. for the second stabilization step, 260 ° C. for the third stabilization step, and 270 ° C. for the fourth stabilization step. The temperature increase time to the temperature set in the oven was set to 1 minute, and the residence time for each section was set as the temperature corresponding to 1/4 of the total process time minus one minute of the temperature increase time. Therefore, the first stabilization step to the fourth stabilization step were each composed of 10 minutes residence after 1 minute warming up, and the time of the entire stabilization step was 44 minutes.

Ozone gas was added when the third stabilization step was performed.

Ozone gas was supplied to the fiber through the shower head at the top of the oven by opening the gas valve connected to the ozone generator from the start of the temperature rise to the input period until the start of the next temperature rise. The ozone generator used PC-57 equipment of Ozone Tech Co., Ltd., the pressure inside the generator was set to 1 kg / ㎠, the input oxygen flow rate was 3 L / min, and the discharge current was 3.2 A. The concentration of ozone gas in the oven measured at 15 ° C. under the above set conditions was 2,197 ppm. The concentration of the ozone gas was measured by OZM-7000GN equipment of Okirotec.

<Carburizing Step>

Samples were fixed by cutting carbon paper made of graphite (Carbon Paper) into an appropriate size, arranging stabilizing fibers in parallel, and attaching a carbon tape in a direction perpendicular to the fibers. Thereafter, the carbon paper was folded to separate each stabilizing fiber in a separate space, and connected with commercial carbon fiber to purge for 20 minutes in a carbonized carbonization furnace. The carbonization furnace is a type in which a Joule heating type electric furnace and a quartz tube are combined, and the temperature is set to 1,200 ° C. After purging, the carbon fibers were wound at a constant speed so that carbon paper containing stabilized fibers was positioned at the center of the carbonization furnace, and the carbon fibers were prepared by staying for 5 minutes.

< Example  2>

Stabilizing fibers and carbon fibers were prepared in the same manner as in Example 1, except that ozone gas was added during the fourth stabilization step instead of the third stabilization step.

< Example  3>

<Step to stabilize>

Stabilization fiber was prepared by performing a stabilization process using PAN fiber as a raw material.

Specifically, the stabilization process was performed by sequentially passing the PAN fibers wound around the branch pipe in one direction through the traveling roller and sequentially passing the first to fourth ovens set at four different temperatures.

The first to fourth ovens are all ovens in which hot air circulates in an end-to-end manner, and a heat zone has a length of 4.5 m. The first oven was set to 222 ° C. and a first stabilization step was performed. The second oven was set to 237 ° C. and a second stabilization step was performed. The third oven was set to 247 ° C. and a third stabilization step was performed. The fourth oven was set to 253 ° C. and a fourth stabilization step was performed.

On the other hand, the injection speed of the PAN fiber for the first stabilization step was set to 0.45 m / min. The total stabilization step time was 40 minutes based on the injection speed of the PAN fiber and the tension was maintained at 750 to 850 gf by adjusting the roller speed thereafter.

Ozone gas was added when the fourth stabilization step was performed. The ozone gas was supplied from the door of the fourth oven in which the fourth stabilization step is performed through an input tube made of SUS material inserted into the inner space through which the fiber passes. The ozone generator used two OZE-020 equipments of Ozone Engineering Co., Ltd., and ozone generator pressure was 1 kg / ㎠, input oxygen flow rate was 14 ℓ / min, and the discharge current was controlled under the above setting conditions. The concentration of ozone gas in the oven measured at 15 ° C. was 624 ppm. The concentration of the ozone gas was measured by OZM-7000GN equipment of Okirotec.

<Carburizing Step>

The obtained stabilized fibers were carbonized through a continuous carbonization plant in which two carbonization furnaces were connected in series to prepare carbon fibers. Specifically, the carbonization furnace is a type in which a Joule heating electric furnace and a quartz tube are combined, and the temperatures are set to 850 ° C. and 1,200 ° C., respectively. Nitrogen gas was flowed into each carbonization furnace by 40 l / min to prevent oxidation and combustion, and it was constantly moved at a speed of 0.5 m / min through the traveling roller, stayed in each carbonization furnace for 1 minute, and the stabilizing fibers were carbonized. .

< Example  4>

When ozone is added, the ozone gas pressure is 1 kg / cm2, the input oxygen flow rate is 14 l / min, and the concentration of ozone gas in the oven measured at 15 ° C by controlling the discharge current under the above set conditions is 1,080 ppm. Except for the stabilizing fibers and carbon fibers were prepared in the same manner as in Example 3.

< Example  5>

When ozone is charged, the ozone generator has a pressure of 1 kg / cm2, an input oxygen flow rate of 14 l / min, and an ozone gas concentration of 1,363 ppm measured at 15 ° C by adjusting the discharge current under the above set conditions. Except for the stabilizing fibers and carbon fibers were prepared in the same manner as in Example 3.

< Example  6>

When ozone is added, the ozone generator pressure is 1 kg / ㎠, the input oxygen flow rate is 14 l / min, and the concentration of ozone gas in the oven measured at 15 ° C. is 1,931 ppm by adjusting the discharge current under the above set conditions. Except for the stabilizing fibers and carbon fibers were prepared in the same manner as in Example 3.

< Comparative example  1>

Stabilizing fibers and carbon fibers were prepared in the same manner as in Example 1 except that ozone gas was not added.

< Comparative example  2>

Stabilizing fibers and carbon fibers were prepared in the same manner as in Example 1 except that ozone gas was added during the first stabilization step instead of the third stabilization step.

< Comparative example  3>

In Example 1, stabilizing fibers and carbon fibers were prepared in the same manner as in Example 1 except that ozone gas was added during the second stabilization step instead of the third stabilization step.

< Comparative example  4>

Stabilization was carried out in the same manner as in Example 1, except that the first stabilization step to the fourth stabilization step were each set to 12 minutes after the temperature was raised for 1 minute without the addition of ozone gas. Fibers and carbon fibers were prepared.

< Comparative example  5>

Stabilization was carried out in the same manner as in Example 1, except that the first stabilization stage to the fourth stabilization stage were each heated for 15 minutes and the residence time was 15 minutes without adding ozone gas. Fibers and carbon fibers were prepared.

< Comparative example  6>

Stabilizing fibers and carbon fibers were prepared in the same manner as in Example 3 except that ozone gas was not added.

< Experimental Example >

Carbon fiber  Properties

The physical properties of the carbon fibers of Examples and Comparative Examples were evaluated in the following manner, and the results are shown in the following [Table 1] and [Table 2].

※ Tensile strength, elasticity, and elongation: Based on ASTM D 1577, ASTM D 3822, and ASTM D 3822M-14, textechno's Favimat + equipment is used to measure linear density and tensile test of single fibers. Tensile strength, elasticity, and elongation of carbon fibers were measured.

division	Example
	One	2	3	4	5	6
Oven can	One	One	4	4	4	4
Ozone Gas Input Section	Third stabilization step	4th stabilization step	4th stabilization step	4th stabilization step	4th stabilization step	4th stabilization step
Concentration of ozone gas	2,197	2,197	624	1,080	1,363	1,931
Number of minutes for full stabilization phase	44	44	40	40	40	40
The tensile strength	3.14	3.34	3.02	3.43	3.22	3.17
Shout	200	201	196	199	201	195
Elongation	1.77	1.83	1.68	1.88	1.75	1.77

division	Comparative example
	One	2	3	4	5	6
Oven can	One	One	One	One	One	4
Ozone Gas Input Section	Not input	First stabilization step	Second stabilization step	Not input	Not input	Not input
Concentration of ozone gas	-	2,197	2,197	-	-	-
Number of minutes for full stabilization phase	44	44	44	52	64	40
The tensile strength	2.63	1.32	2.74	2.74	3.03	2.93
Shout	186	155	185	188	200	196
Elongation	1.61	1.1	1.66	1.63	1.67	1.61

Referring to Tables 1 and 2, the carbon fibers of Examples 1 and 2, in which the ozone gas is injected in the third or fourth stabilization step, but are stabilized in a batch oven, do not use ozone gas, or It can be seen that the tensile strength, elasticity and elongation are all excellent compared to the carbon fibers of Comparative Examples 1 to 3 in which ozone gas is added in the second stabilization step. It was confirmed that the tensile strength and elongation were significantly superior to those of the carbon fibers of Comparative Examples 4 and 5, which performed the stabilization process for 52 minutes and 64 minutes.

In addition, the carbon fibers of Examples 4 to 6 performed in the stabilization step in four ovens, but the ozone gas is added in the fourth stabilization step, the tensile strength and the carbon fiber of Comparative Example 6 without the addition of ozone gas and It was confirmed that the elongation was remarkably excellent. In addition, when comparing the carbon fibers of Examples 3 to 6, the carbon fibers of Examples 4 to 6 having an ozone gas concentration of 1,080 to 1,931 ppm and the tensile strength of the carbon fibers of Example 3 having a concentration of 624 ppm of ozone gas , And the elongation was excellent.

Claims (11)

1. Preparing precursor fibers for producing carbon fibers; And

   Stabilizing the precursor fiber,

   The stabilizing of the precursor fiber may include setting a first stabilization step, a second stabilization step, and a third temperature different from a temperature at which heat generation starts according to the stabilization reaction of the precursor fiber and a temperature at which the heat generation indicates a maximum. A stabilization step and a fourth stabilization step,

   The method of stabilizing the precursor fiber for producing carbon fiber is to inject ozone gas when performing at least one of the third stabilization step and the fourth stabilization step.
2. The method according to claim 1,

   The first stabilization step is set to a temperature within 45 ℃ from the temperature at which the exotherm according to the stabilization reaction of the precursor fiber starts,

   The second stabilization step to the fourth stabilization step, the stabilization method of the precursor fiber for producing carbon fiber is set to 5 ℃ to 45 ℃ high sequentially based on the temperature set in the first stabilization step.
3. The method according to claim 1,

   The concentration of the ozone gas is 450 ppm or more at 15 ℃ the stabilization method of the precursor fiber for producing carbon fibers.
4. The method according to claim 1,

   The concentration of the ozone gas is 450 ppm to 3,000 ppm at a stabilization method of the precursor fiber for producing carbon fibers.
5. The method according to claim 1,

   Stabilizing the precursor fiber is a method of stabilizing the precursor fiber for producing carbon fiber is carried out in 60 minutes or less.
6. The method according to claim 1,

   The first stabilization step to the fourth stabilization step is a method of stabilizing the precursor fiber for producing carbon fiber, which are each independently performed in 15 minutes or less.
7. The method according to claim 1,

   Stabilizing the precursor fiber is carried out in a batch type oven, or a method of stabilizing the precursor fiber for producing carbon fiber, wherein the precursor fiber is continuously passed through a plurality of ovens each set to a different temperature.
8. The method according to claim 1,

   The precursor fiber is one of polyacrylonitrile (PAN) -based fibers, pitch-based fibers, rayon-based fibers, lignin-based fibers, cellulose-based fibers, and polyethylene-based fibers. The stabilizing method of the precursor fiber for carbon fiber manufacture which contains the above.
9. The method according to claim 1,

   The precursor fiber is a polyacrylonitrile (PAN: polyacrylonitrile) fiber,

   The stabilizing of the precursor fiber may include a first stabilization step set at a temperature of 205 ° C. to 240 ° C., a second stabilization step set at a temperature of 220 ° C. to 255 ° C., and a third stabilization step set at a temperature of 235 ° C. to 265 ° C. And a fourth stabilization step set at a temperature of 250 ° C. to 280 ° C.,

   The first stabilization step, the second stabilization step, the third stabilization step and the fourth stabilization step is a stabilization method of the precursor fiber for producing carbon fiber is set to a different temperature, respectively.
10. Preparing a precursor fiber for producing carbon fiber stabilized by any one of claims 1 to 9; And

    Carbonizing the stabilized precursor fiber for producing carbon fibers

    Method for producing a carbon fiber comprising a.
11. The method according to claim 10,

    The carbonizing step of the precursor fiber, the carbon fiber manufacturing method of producing a carbon fiber to stabilize the precursor fiber for producing carbon fiber using heat energy or microwave.