KR20190044588A - And method for producing the same, and a method for producing carbon fiber precursor fibers and carbon fibers - Google Patents

Abstract

And a carbon fiber precursor fiber using the same, and a carbon fiber using the carbon fiber precursor fiber. The coagulum used in the production of carbon fiber is a coagulum having a surface pore diameter of 30 nm or less and a swelling degree of less than 100%, or a coagulation agent having a surface pore diameter of 30 nm or less and an inner layer pore diameter of 30 nm or less. Using this criterion, carbon fiber precursor fibers and carbon fibers are obtained.

Description

And method for producing the same, and a method for producing carbon fiber precursor fibers and carbon fibers

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to carbon fibers suitable for use in sports applications such as golf shafts and fishing rods, and other general industrial applications, including aircraft members, automobile members and ship members.

Since carbon fiber has a low specific gravity, high nasal rigidity and a high non-elasticity ratio, it has been widely used as a reinforcing fiber for a composite material in sports applications and aerospace applications. BACKGROUND ART In recent years, applications of automobiles, civil engineering and construction applications, pressure vessels, windmill blades, and the like have been expanded.

It is known that the performance of the carbon fiber largely depends on the performance of the carbon fiber precursor fiber. In particular, when a surface layer of carbon fiber precursor fibers has irregularities, a dry wet spinning method which is considered to cause a decrease in the strength of the carbon fiber and which tends to form a smooth surface has been proposed. However, .

For example, Patent Document 1 proposes a technique of controlling the conditions of the step of dry-wet spinning and the step of stretching the bath using a water-based coagulation bath and densifying the surface layer to suppress the intrusion of the emulsion, .

Patent Document 2 proposes a technique of reducing voids of solidified yarn by dry-wet spinning using a coagulating bath comprising paraffinic hydrocarbon.

As a technique characterized by a solidification process, Patent Document 3 proposes a technique in which a low-concentration polymer solution is gelled in a low-temperature coagulating bath composed of alcohol and the productivity is improved by increasing the process speed by stretching at a high magnification.

Patent Document 1: International Publication No. 2010/143680 Patent Document 2: JP-A-2-74607 Patent Document 3: JP-A-2010-100970

Using a coagulant obtained by densifying the surface layer described in Patent Document 1 and coagulation with less voids described in Patent Document 2, an effect of improving the strength of the carbon fiber was obtained, but the effect was not sufficient.

In Patent Document 1, it is said that it is preferable to stretch coagulation with a degree of swelling of 160% or less under specific conditions, and an example of swelling degree of 100 to 155% is shown in the examples. However, according to the studies of the present inventors, it has been found that the swelling degree of 100% or more is insufficient in order to greatly improve the strength. Patent Document 2 discloses a technology for further reducing the swelling degree. However, according to the studies of the present inventors, it has been found that if the proportion of paraffinic hydrocarbons is increased in order to reduce the swelling degree, the coagulation speed is slow, And the pore diameter of the surface layer was large and the degree of swelling was reduced. However, it was found that the effect of improving the strength was limited. The technique of Patent Document 3 has the effect of improving the productivity but does not necessarily have the effect of improving the strength. This is because the polymer concentration of the polymer solution is low and it is therefore difficult to obtain the compactness required for achieving high strength in the solidification step.

An object of the present invention is to provide a carbon fiber and a carbon fiber precursor fiber for obtaining carbon fibers having high strength, and a carbon fiber using the carbon fiber precursor fiber.

In order to solve the above problems, the coagulant of the present invention has a surface pore diameter of 30 nm or less, a swelling degree of less than 100%, or a surface pore diameter of 30 nm or less and an inner layer pore diameter of 30 nm or less.

The carbon fiber precursor fiber according to the present invention has a surface layer pore diameter of 30 nm or less and a swelling degree of less than 100% or a surface layer pore diameter of 30 nm or less and an inner layer pore diameter of 30 nm or less, A high strength carbon fiber is obtained.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a diagram showing a TEM image of a surface layer of coagulated yarn of Example 1. Fig.
2 is a diagram showing a TEM image of the coagulation internal layer of Example 1. Fig.
3 is a TEM image of the surface layer of the coagulation sample of Comparative Example 1. Fig.
4 is a diagram showing a TEM image of the coagulum inner layer of Comparative Example 1. Fig.

The present invention is to obtain a carbon fiber having high strength by controlling the pore size of the surface layer of the coagulated yarn to be small and controlling the swelling degree to be extremely small. In another form, the pore diameter of the surface layer of the coagulated yarn is controlled to be small and the pore hardness of the inner layer is controlled to be small, thereby obtaining a carbon fiber having high strength.

The carbon fiber precursor fiber in the present invention is a precursor fiber that can be carbonized, and is, for example, a fiber that has been stretched.

[Reply]

(The pore size of the surface layer of the coagulant)

The coagulating agent of the present invention has a surface pore diameter of 30 nm or less. The smaller the size, the higher the strength tends to be. Therefore, the surface pore diameter is preferably 20 nm or less, and more preferably 10 nm or less. When the surface pore size is 1 nm or less, the lower limit is about 1 nm since it takes time for desolvation in the washing step. The surface pore diameter of 1 nm to 10 nm is more preferable because the carbon fiber strength and processability are balanced.

The surface layer in the present invention is within a range of 500 nm from the outer periphery toward the inner periphery in cross section in the fiber length direction. The pore size refers to the size of the pores formed by the fibril structure of the solidification yarn and the voids contained therein.

(Swelling degree of coagulant)

One of the forms of the present invention is that the swelling degree of the coagulated yarn is less than 100%. When the surface pore diameter falls within the aforementioned range, the degree of swelling tends to increase as the swelling degree decreases, so that it is preferably less than 90% and more preferably less than 85%. When the degree of swelling is 3% or less, since the time for desolvation in the washing step takes time, the lower limit is about 3%. A swelling degree of 3% to 85% is more preferable because a balance between the carbon fiber strength and the processability can be obtained.

(Pore size of inner layer of coagulant)

In another aspect of the present invention, the coagulum inner layer pore diameter is 30 nm or less. When the surface pore diameter falls within the aforementioned range, the inner layer pore diameter tends to increase as the inner layer pore diameter decreases. Therefore, the inner layer pore diameter is preferably 20 nm or less, more preferably 10 nm or less. When the inner layer pore size is 1 nm or less, the lower limit is about 1 nm since it takes time for desolvation in the washing step. It is more preferable that the inner layer pore diameter is 1 nm to 10 nm because balance between the carbon fiber strength and the processability can be obtained.

The inner layer referred to in the present invention is a range of a circle within a diameter of 500 nm at the center (center of gravity) of the cross section in the cross section in the fiber diameter direction. The pore size refers to the size of the pores formed by the fibril structure of the solidification yarn and the voids contained therein.

[Production method of solidification product]

The coagulant of the present invention can be obtained, for example, by mixing a non-solvent having a solubility parameter of -11 to +20 with respect to the solubility parameter of the polymer forming the coagulation and a solvent of the polymer solution used for forming the coagulum, : 9 to 9: 1, and then solidifying the polymer.

Further, in the present invention, after the polymer solution is discharged from the spinneret in the spinning step and introduced into the coagulation bath in the coagulation step to precipitate the polymer, coagulation is formed, and thereafter the spinning step, the stretching in bath It is preferable to obtain a carbon fiber precursor fiber through a process and a drying process. The coagulant of the present invention can also be produced by wet spinning or dry-wet spinning of the polymer solution. At this time, the pore size and degree of swelling can be controlled in accordance with a condition of solidifying the polymer solution in the coagulating bath, that is, a condition of precipitating the polymer in the polymer solution from the solvent.

(Spinning process)

The spinning method may be either wet spinning or dry spinning spinning. However, as described later, in the present invention, it is preferable to set the temperature of the coagulation bath to a low level. On the other hand, from the viewpoint of radioactivity, the polymer solution needs to have a temperature at which constant fluidity can be obtained, and the temperature of the coagulation bath and the temperature of the polymer solution There are many cases where you set the difference. For this reason, a dry-wet spinning method in which the difference between the coagulating bath temperature and the polymer temperature (polymer discharge port temperature) is liable to occur is preferable.

The polymer used in the present invention is not particularly limited as long as it is carbonizable, and is, for example, a copolymer comprising polyacrylonitrile or polyacrylonitrile as a main component and a mixture comprising polyacrylonitrile as a main component. In the description of the present invention, when there is no particular rejection, a copolymer containing polyacrylonitrile as a main component is referred to as a polymer.

The solvent of the polymer is not particularly limited as long as it dissolves the polymer, and examples thereof include dimethyl sulfoxide, dimethyl formamide, and dimethylacetoamide.

The concentration of the polymer in the polymer solution is not particularly limited, but is preferably 10% by mass or more because the degree of swelling tends to be small due to the high polymer concentration. When the polymer is dissolved in a solvent, the upper limit is not particularly limited, but is generally 30 mass% or less. The higher polymer concentration is preferable even when the pore size is reduced.

The higher the temperature of the polymer solution discharged from the nip, the more easily the fluidity is obtained. On the other hand, the lower the temperature of the polymer solution, the easier the precipitation in the coagulating bath becomes. If the polymer is easily precipitated in the coagulation bath, the growth of the size becomes difficult to progress during the liquid-liquid phase separation process, and thus the pore diameter is liable to be small. For this reason, the temperature of the polymer solution is preferably 15 to 95 占 폚.

(Solidification step)

The coagulant of the present invention can be obtained, for example, by mixing a non-solvent having a solubility parameter of -11 to +20 with respect to the solubility parameter of the polymer forming the coagulation and a solvent of the polymer solution used for forming the coagulum, : 9 to 9: 1, and then solidifying the polymer. The solubility parameter referred to in the present invention is the Hansen solubility parameter (MPa ^0.5 ).

The larger the difference between the solubility parameter of the non-solvent and the solubility parameter of the polymer, the more difficult it is to dissolve. The present invention has found that the degree of swelling and the pore size of the inner layer can be reduced by selecting a non-solvent which is close to the solubility parameter of the polymer. With respect to the solubility parameter of the polymer, the solubility parameter of the non-solvent is preferably -9 to +15, more preferably -7 to +10. When polyacrylonitrile is used as the polymer, the solubility parameter of polyacrylonitrile is 27.4, and the preferable non-solvent solubility parameter is 16.4 to 47.4. Examples of such non-solvent include methanol, ethanol, propanol, butanol, glycerin, ethylene glycol, propylene glycol, butanediol, acetic acid, ethyl acetate, acetone, benzene, toluene, xylene, cyclohexane, methyl ethyl ketone and chloroform have. In this case, the polymer is precipitated by adding to the polymer solution in an environment of normal pressure and room temperature. The solubility parameter uses, for example, the value of a handbook (see Hansen Solubility Parameters A User's Handbook Second Edition, CRC Press (2007)) or a value calculated by the method described. When the polymer is a mixture, the difference between the non-solvent solubility parameter (?) And the solubility parameter of each polymer is compared, and a non-solvent having a solubility parameter of -11 to +20 relative to the solubility parameter of at least one polymer is used will be. When the non-solvent is a mixture, all three parameters of the dispersion force (? _D ), the dipole interaction (? _P ) and the hydrogen bond (? _H ) are added together in accordance with the volume fraction of the mixture, , The square root is taken as the solubility parameter of the non-solvent.

For example, cost-solvent non-solvent A, the case of two-component mixture consisting of B, the mixed-solvent δ _d, δ _p, δ _h, the

[Number 1]

to be. Here, φ _A and φ _B are the volume fraction of the mixture, and φ _A + φ _B = 1. The solubility parameter (δ) of the mixed non-solvent is calculated according to δ _d , δ _p , and δ _h of the calculated mixed solvent

[Number 2]

.

Further, the present inventors have found that the pore size of the surface layer and the inner layer can be controlled by mixing the solvent of the polymer into the coagulating bath. In addition, although roundness tends to decrease with the use of the non-solvent of the above-mentioned range, an effect of increasing the roundness degree with a small swelling degree is found by increasing the amount of the polymer solvent. On the other hand, when the polymer solvent is reduced, the pore size of the surface layer and the inner layer can be decreased. In the form of the present invention, the ratio of non-solvent: solvent = 2: 8 to 8: 2 is more preferable, and the ratio of non-solvent: solvent = 3: 7 to 7: : 6 to 6: 4 is more preferable. In addition, other substances may be included within the range not impairing the effect of the present invention. Also, the ratio is the ratio of mass.

It is a non-solvent of the diffusion coefficient D in the coagulating bath in the invention 3.4 × 10 ^-10 ㎡ · S ^-1 or less is preferable. The smaller the diffusion coefficient D is, the smaller the swelling degree of the obtained coagulated yarn and the pore size of the surface layer and the inner layer. Here, the non-solvent diffusion coefficient D is obtained by the pulse magnetic field gradient nuclear magnetic resonance method (PFG-NMR method). In PFG-NMR, information on the diffusion travel distance of the substance, that is, the position of the nuclear spin can be obtained by applying a pulse magnetic field gradient (PFG) in the direction of the static magnetic field in ordinary NMR measurement.

Specifically, the attenuation of the target peak intensity based on the PFG intensity change is tracked, and the diffusion coefficient is obtained from the slope according to the exponential function analysis of the attenuation change. In order to measure the nondiscriminatory diffusion coefficient D using actual PFG-NMR, an NMR apparatus equipped with a Diff60 probe (AVANCE III HD 400 manufactured by Bruker Biospin) was used to calculate the Stejskal-Tanner equation:

. Where G is the magnetic field gradient intensity,? Is the magnetic field gradient pulse width,? Is the interval (diffusion time) of the magnetic field gradient pulse, and? Is the nuclear magnetic rotation ratio of the observation nucleus. The signal intensity I is plotted against G ² γ ² α ² (Δ-α / 3) obtained by normalizing the signal intensity I ₀ when G is the minimum and I n (I / I ₀ ) The coefficient D was obtained. When two or more types of coagulants are included, D of the coagulant is defined as D of the non-coagulant (the most diffusible coagulant) having the largest diffusion coefficient D,

The coagulating bath in the present invention preferably has a viscosity of 2 to 1000 mPa · s. The degree of swelling is likely to be lowered due to the high viscosity of the coagulating bath, and the viscosity of the coagulating bath is low, so that the polymer tends to precipitate and the pore size is liable to become small. The viscosity of the coagulating bath is more preferably from 5 to 500 mPa · s, and further preferably from 10 to 200 mPa.

In addition, the coagulating bath in the present invention preferably has a temperature lower by 10 to 100 占 폚 than the polymer discharged from the spinneret. The lower the temperature of the coagulating bath is, the more easily the polymer is precipitated, so that the pore size is easily reduced. On the other hand, if the temperature of the coagulating bath is raised, the fiber production is improved, and fibers having little fluff or adhesion between the fibers are easily obtained. The temperature of the coagulating bath is more preferably lower than that of the polymer solution by 20 to 80 占 폚, and more preferably by 30 to 60 占 폚.

[Production method of carbon fiber precursor fiber]

Next, a method for producing the carbon fiber precursor fiber of the present invention will be described.

In the present invention, it is preferable that the method for producing a carbon fiber precursor fiber includes a step of forming a coagulum by the above-mentioned method and then drawing. Further, it is more preferable to obtain the carbon fiber precursor fibers through the washing step, the drawing step in the bath, the emulsion applying step and the drying step after the coagulation is formed. It is also preferable to add a dry heat drawing process or a vapor drawing process to the above-described process. The yarn after solidification may be stretched in a direct bath by omitting the washing step, or may be stretched in a bath after removing the solvent in the washing step.

After the stretching process in the bath, from the viewpoint of preventing adhesion of the short fibers to each other, it is preferable to apply a silicone-based emulsion to the stretched fiber yarn.

It is preferable to dry after applying the emulsion. In addition, it is preferable to perform stretching in the heated fiber after the drying step in order to improve the productivity and improve the degree of crystal orientation. As the heated fruit, for example, pressurized steam or superheated steam is suitably used in view of operational stability and cost.

When the stretching ratio is increased, the molecules tend to align in the fiber axis direction, so that the tensile strength at the time of carbon fiber formation tends to be improved. On the other hand, reducing the stretching magnification makes it easier to improve the uniformity in the longitudinal direction of the fibers. For this reason, it is preferable that the total draw ratio is at least 1 time and less than 20 times.

[Production method of carbon fiber]

Next, a method for producing the carbon fiber of the present invention will be described.

In the present invention, it is preferable that the method for producing a carbon fiber includes a step of obtaining a carbon fiber precursor fiber and then heat-treating the carbon fiber precursor fiber. The heat treatment step referred to herein is not particularly limited as long as it can heat the carbon fiber precursor fibers when the carbon fiber precursor fibers are carbonized. Examples of the heat treatment step include a chlorination step, a preliminary carbonization step, a carbonization step, Process.

In the present invention, the carbon fiber precursor fibers obtained as described above are subjected to a deoxidation step in which air is chlorinated in air at a temperature of 200 to 300 ° C, and a step in which the fibers obtained in the deoxidation step are subjected to heat treatment at a temperature of 300 to 800 ° C. in an inert atmosphere The preliminary carbonization step for preliminary carbonization and the carbonization step for carbonizing the fibers obtained in the preliminary carbonization step in an inert atmosphere at a temperature of 1,000 to 3,000 DEG C are successively performed to obtain carbon fibers.

When a carbon fiber having a higher modulus of elasticity is desired, graphitization may be performed subsequent to the carbonization step. The temperature of the graphitization step is preferably 2,000 to 2,800 ° C. Further, the maximum temperature is appropriately selected and used according to the required properties of the desired carbon fiber. The stretching ratio in the graphitization step is suitably selected in accordance with the desired properties of the desired carbon fiber within a range that does not cause degradation such as napping.

(Surface Modification Process)

The surface of the obtained carbon fiber is subjected to electrolytic treatment. This is because the adhesiveness to the carbon fiber matrix in the fiber-reinforced composite material obtained by the electrolytic treatment can be optimized. The brittle fracture of the composite material due to too strong adhesion and the problem of lowering the tensile strength in the fiber direction and the tensile strength in the fiber direction are high but the adhesiveness to the resin is poor and the strength characteristics in the non- The problem of not being expressed is solved. As a result, in the obtained fiber-reinforced composite material, a balanced strength characteristic is exhibited in both the fiber direction and the non-fiber direction.

After the electrolytic treatment, a sizing treatment may be carried out in order to give the carbon fiber an aggregate property. As the sizing agent, a sizing agent having good compatibility with the matrix resin can be appropriately selected depending on the kind of the resin to be used.

Example

Data in Examples and Comparative Examples were measured by the following methods.

1. Pore size of coagulant

(1) Sample preparation

The liquid contained in the coagulant was replaced with water. Next, the coagulum obtained by freeze-drying the water-substituted coagulum was embedded in a resin, and a section of 100 nm was prepared with an ultra-microtome.

(2) Observation

After removing the resin in the prepared slice, the slice was observed with a transmission electron microscope at an acceleration voltage of 100 kV. At this time, the cross section in the fiber diameter direction was observed at a magnification of 10,000 times.

(3) Pneumatic measurement

A. Noise was removed by using the image processing software JTrim ver. 1.53 c (JTrim) with the applied intensity set to 50.

B. Using JTrim, normalization of the histogram was performed on the image obtained in A.

C. JTrim was used, and the image obtained in B. was subjected to two-step harmonization (thresholding) at a boundary threshold of 145.

D. Image Processing Software ImageJ 1.50 i (ImageJ) was used, and an area was selected as an area selection tool for the image obtained in C. (Surface layer: 500 nm inward from the outer periphery, inner layer: A range of a circle with a diameter of 500 nm).

E. Image Processing Software ImageJ 1.50 i (ImageJ) was used to measure the area of the portion corresponding to the pores with respect to the image obtained in D. using a particle analysis command, and the area was calculated on the basis of the area of the pore.

The average value of the particle diameters obtained from F. E., which is the second largest to the 31st largest, was defined as the particle diameter. When 31 pieces were not detected, the value of the detected range was used.

2. Swelling degree of coagulation company

First, sample 10 g of the sample and wash it for 12 hours or more. Next, the fiber mass after dewatering is dehydrated in a centrifugal dehydrator (for example, KOKUSAN Co. Ltd., H-110A) at 3000 rpm for 3 minutes. Thereafter, the dewatered sample is dried in a dryer controlled at a temperature of 105 ° C for 2.5 hours, and the fiber mass after drying is determined, and the fiber swelling degree is calculated by the following formula.

Expression: fiber swelling degree (%) = ((fiber mass after dehydration - fiber mass after drying) / fiber mass after drying)) × 100.

3. Tensile strength and elastic modulus of carbon fiber bundles

JIS R7608 (2007) " Test method for tensile properties using carbon fiber-resin impregnated yarn samples ". The resin-impregnated strand of the carbon fiber to be measured was a mixture of 3, 4-epoxycyclohexylmethyl-3, 4-epoxy-cyclohexylcarboxylate (100 parts by weight) / boron trifluoride monoethylamine (3 parts by weight) 4 parts by mass) was impregnated with carbon fiber or graphitized fiber and cured at a temperature of 130 캜 for 30 minutes. The number of strands of the carbon fiber was measured to be 6, and the average value of each measurement result was regarded as tensile strength. In this example, "Bakelite" (registered trademark) ERL4221 manufactured by Union Carbide Corporation was used as 3, 4-epoxycyclohexylmethyl-3,4-epoxy-cyclohexylcarboxylate.

4. Measurement of Diffusion Coefficient (D)

Based on the PFG-NMR method, the diffusion coefficient (D) of the non-solvent of each coagulating bath was measured using an NMR apparatus (AVANCE III HD 400 manufactured by Bruker Biospin) equipped with a Diff60 probe. The measurement temperature was 5 占 폚.

(Example 1)

A copolymer composed of acrylonitrile and itaconic acid was polymerized in a solution polymerization method using dimethylsulfoxide as a solvent and a polymerization initiator to prepare a polyacrylonitrile copolymer, which was used as a spinning solution.

The resulting spinning solution was controlled at 50 占 폚 and once discharged into the air, introduced into a coagulating bath in which 48% by mass of dimethyl sulfoxide as a polymer solvent controlled at 5 占 폚 and 52% by mass of non-solvent ethylene glycol were mixed, The spinning draft at a spinning draft of 2.5 was made into a coagulated yarn by wet spinning. The coagulated yarn was washed in a water bath and then stretched in a water bath. Subsequently, an amino-modified silicone-based silicone emulsion was applied to the fiber bundle after the water-bath stretching, and the fiber was subjected to dry densification treatment using a heating roller and stretched in a pressurized steam, 0.8 dtex of polyacrylonitrile-based carbon fiber precursor fiber was obtained. Next, the obtained polyacrylonitrile-based carbon fiber precursor fibers were subjected to a chlorination treatment in air having a temperature gradient of 220 to 270 DEG C to obtain a chlorinated fiber bundle. The obtained dechlorinated fiber bundle was subjected to preliminary carbonization treatment in a nitrogen atmosphere at a temperature of 300 to 800 DEG C to obtain a preliminary carbonized fiber bundle. The obtained preliminary carbonized fiber bundles were carbonized at a maximum temperature of 1400 ° C in a nitrogen atmosphere. Subsequently, an aqueous sulfuric acid solution was electrolytically surface-treated as an electrolytic solution, followed by washing with water and drying, followed by a sizing agent to obtain carbon fibers.

(Example 2)

Carbon fiber was obtained in the same manner as in Example 1 except that methanol was used as a non-coagulating bath.

(Example 3)

Carbon fiber was obtained in the same manner as in Example 1 except that the coagulating bath temperature was controlled at 45 캜.

(Example 4)

Carbon fiber was obtained in the same manner as in Example 1 except that n-butanol was used as a non-coagulant in the coagulating bath and the ratio of the n-butanol to the polymer solvent was changed.

(Example 5)

Carbon fiber was obtained in the same manner as in Example 1 except that glycerin and ethanol were used as non-coagulating baths.

(Example 6)

Carbon fiber was obtained in the same manner as in Example 1 except that dimethylformamide was used as the polymer solvent.

(Example 7)

Carbon fiber was obtained in the same manner as in Example 1 except that ethylene glycol and ethanol were used as a non-coagulating bath and the proportion of the polymer solvent was changed.

(Example 8)

Carbon fibers were obtained in the same manner as in Example 1 except that propylene glycol and ethanol were used as non-coagulating baths and the ratios of the polymer solvent and the coagulating bath were changed.

(Example 9)

Carbon fiber was obtained in the same manner as in Example 1 except that water and glycerin were used as the non-coagulating bath and the ratio of the solvent to the polymer solvent was changed. D viewing on the basis of the PFG-NMR was ^{2.7 × 10 -10 ㎡ · S -1} .

(Example 10)

Carbon fiber was obtained in the same manner as in Example 1 except that water and ethylene glycol were used as a non-coagulant in the coagulating bath and the ratio of the polymer and the solvent was changed. D viewing on the basis of the PFG-NMR was ^{2.7 × 10 -10 ㎡ · S -1} .

(Example 11)

Carbon fiber was obtained in the same manner as in Example 10 except that the coagulating bath temperature was controlled at 25 캜.

(Example 12)

Carbon fiber was obtained in the same manner as in Example 10 except that the coagulating bath temperature was controlled to -15 캜.

(Example 13)

Carbon fiber was obtained in the same manner as in Example 1 except that water and propylene glycol were used as a non-coagulant in the coagulating bath and the ratio of the polymer solvent to the water was changed. D viewing on the basis of the PFG-NMR was ^{3.3 × 10 -10 ㎡ · S -1} .

(Example 14)

Carbon fiber was obtained in the same manner as in Example 1 except that water and methanol were used as a non-coagulant in the coagulating bath and the ratio of the solvent to the polymer solvent was changed. D viewing on the basis of the PFG-NMR was ^{4.4 × 10 -10 ㎡ · S -1} .

(Example 15)

Carbon fiber was obtained in the same manner as in Example 1 except that water and ethanol were used as a non-coagulant in the coagulating bath and the ratio of the solvent and the polymer solvent was changed. D viewing on the basis of the PFG-NMR was ^{3.4 × 10 -10 ㎡ · S -1} .

(Example 16)

Carbon fiber was obtained in the same manner as in Example 1 except that water and 1-propanol were used as a non-coagulant in the coagulating bath and the ratio of the polymer solvent to the solvent was changed. D viewing on the basis of the PFG-NMR was ^{5.3 × 10 -10 ㎡ · S -1} .

(Comparative Example 1)

Carbon fibers were obtained in the same manner as in Example 1 except that water was used as a non-coagulant in the coagulating bath and the ratio of the polymer solvent to the non-coagulating bath was changed. D viewing on the basis of the PFG-NMR was ^{3.5 × 10 -10 ㎡ · S -1} .

(Comparative Example 2)

A carbon fiber was obtained in the same manner as in Example 1 except that the polymer solvent was not used for the coagulating bath.

(Comparative Example 3)

Carbon fiber was obtained in the same manner as in Example 1 except that liquid paraffin and decanol were used as non-coagulating baths and polymer solvent was not used. The costs and the combinations used are the same as those described in Patent Document 2. The surface layer pore diameter of the obtained coagulated yarn was 42 nm, which was outside the scope of the present invention.

(Comparative Example 4)

Carbon fiber was obtained in the same manner as in Example 1 except that water was used as a non-coagulant in the coagulating bath and dimethyl formamide was used as a polymer solvent and the ratio of the polymer solvent to the polymer solvent was changed. The cost type and the solvent type and mixing ratio used are the same as those described in Patent Document 1. [ The obtained coagulated filament had a surface layer pore diameter of 35 nm and a degree of swelling of 108%, which was outside the scope of claims 1 to 3. D viewing on the basis of the PFG-NMR was ^{5.5 × 10 -10 ㎡ · S -1} .

(Comparative Example 5)

Carbon fibers were obtained in the same manner as in Example 1 except that water was used as a non-coagulant in the coagulating bath and the ratio of the polymer solvent to the non-coagulating bath was changed. D viewing on the basis of the PFG-NMR was ^{5.8 × 10 -10 ㎡ · S -1} .

[Table 1-1]

[Table 1-2]

Claims (11)

As a compliment used in the production of carbon fiber precursor fibers,
Surface roughness less than 30 nm and degree of swelling less than 100%. As a compliment used in the production of carbon fiber precursor fibers,
Having a surface layer porosity of 30 nm or less and an inner layer porosity of 30 nm or less. The method according to claim 1,
Having a surface layer porosity of 30 nm or less and an inner layer porosity of 30 nm or less. A production method of the solidification yarn according to any one of claims 1 to 3,
The non-solvent having a solubility parameter of -11 to +20 with respect to the solubility parameter of the polymer forming the coagulative cords and the solvent of the polymer solution used for forming the coagulated yarn are mixed in a ratio of 1: 9 to 9: 1 By weight based on the total weight of the coagulating bath and the coagulating bath. 5. The method of claim 4,
The diffusion coefficient of the non-solvent ^{3.4 × 10 -10 ㎡ · S -1} , solidification's method using a coagulation bath or less. The method according to claim 4 or 5,
Wherein the coagulating bath has a viscosity of 2 to 1000 mPa · s. 7. The method according to any one of claims 4 to 6,
Wherein the temperature of the coagulating bath is lower than that of the polymer solution by 10 to 100 占 폚. 8. The method according to any one of claims 4 to 7,
And radiating the radiation draft as 1 to 20. A method for producing a carbon fiber precursor fiber, comprising the step of stretching the cord according to any one of claims 1 to 3. 9. A method for producing a carbon fiber precursor fiber, which comprises a step of stretching the coagulum after obtaining coagulation according to the production method of the coagulating yarn according to any one of claims 4 to 8. A process for producing a carbon fiber, which comprises a step of obtaining a carbon fiber precursor fiber according to the production method of the carbon fiber precursor fiber according to claim 9 or 10, and then heat-treating the carbon fiber precursor fiber.

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