KR101659728B1

KR101659728B1 - A method for manufacturing non-woven fabric of composite activated carbon fiber

Info

Publication number: KR101659728B1
Application number: KR1020160038974A
Authority: KR
Inventors: 이성우; 김성훈; 박종오; 장정훈; 김용주
Original assignee: 에스지생활안전 주식회사
Priority date: 2016-03-31
Filing date: 2016-03-31
Publication date: 2016-09-26

Abstract

The present invention relates to a method for producing a composite activated carbon fiber nonwoven fabric comprising a pretreatment step of preliminarily chemically pretreating a first carbon fiber, a stabilization step of stabilizing the pretreated first carbon fiber by heat treatment, A nonwoven fabric in which a fibrous material is mixed with a second carbon fiber having a component different from that of the first carbon fiber to form a nonwoven fabric, and an activation step of heating the nonwoven fabric at a predetermined heating rate for a predetermined period of time to activate the non- A method for producing an activated carbon fiber nonwoven fabric is disclosed.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a method for producing a composite activated carbon fiber nonwoven fabric,

The present invention relates to a method for producing a composite activated carbon fiber nonwoven fabric, which is capable of selectively and collectively adsorbing heterogeneous carbon fibers composed of different components, and also by controlling the content of heterogeneous carbon fibers, To a method for producing a composite activated carbon fiber nonwoven fabric which can be easily controlled in accordance with the intended use.

Activated carbon fibers are advantageous in that the micropores are directly formed on the surface, so that the adsorption of the pollutants is very fast and the shape is fibrous so that it can be easily formed into a fabric or a nonwoven fabric.

Activated carbon fibers have been widely used in various filter fields due to the advantages described above, and recently research and development of technology in the field has been actively performed.

When activated carbon fiber is used as a filter, it is generally used in the form of a nonwoven fabric in which pores having various sizes are irregularly formed so that adsorption and desorption of pollutants can be performed quickly.

Conventionally, the activated carbon fiber nonwoven fabric has a structure in which active carbon fiber layers are sequentially laminated on a support layer on a polyolefin including polyethylene and polypropylene among thermoplastic resins.

At this time, the activated carbon fiber is generally produced by including one selected from the group consisting of polyacrylonitrile (PAN), pitch, rayon, etc. imported from Taiwan, China and the like.

However, conventionally activated carbon fibers are produced through electrospinning without pretreatment of fibers to be precursors, so that there is a limit in increasing the specific surface area of the nonwoven fabric when the activated carbon fibers are made into nonwoven fabric.

In addition, since a single substrate is used as the precursor fiber, the pore size and the degree of formation are uniformly generated at the time of pore formation through the formation of nonwoven fabric and activation, so that sequential and selective adsorption of pollutants is impossible.

Accordingly, there is a need for a method for producing a new activated carbon fiber nonwoven fabric which can overcome the limitations of the conventional activated carbon fiber-based nonwoven fabric.

A problem to be solved by the present invention is to provide a carbon fiber composite material which is capable of selectively and collectively adsorbing a heterogeneous carbon fiber composed of different components and can control the size, And to provide a method for producing a composite activated carbon fiber nonwoven fabric which can be easily controlled in accordance with the application.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are not to be construed as limiting the invention as defined by the artistic scope and spirit of the invention as disclosed in the accompanying claims. It will be possible.

According to another aspect of the present invention, there is provided a method of manufacturing a composite activated carbon fiber nonwoven fabric, the method comprising: a pretreatment step of chemically pretreating a first carbon fiber; Stabilizing the pretreated first carbon fiber by heat treatment to stabilize the first carbon fiber; Forming a nonwoven fabric by mixing the stabilized first carbon fiber with a second carbon fiber having a different component from the first carbon fiber to form a nonwoven fabric; And an activating step of activating the nonwoven fabric by heating the nonwoven fabric at a predetermined heating rate for a predetermined period of time.

Here, the pretreatment step may include a dipping step of immersing the first carbon fiber in an aqueous solution containing one of sulfuric acid, nitric acid, phosphoric acid, sodium chloride, potassium permanganate, and calcium carbonate for 45 minutes to 75 minutes.

The pretreatment may further include washing and drying the first carbon fiber that has been immersed in the aqueous solution.

The stabilization step may be performed at a temperature ranging from 260 ° C to 280 ° C for 45 minutes to 75 minutes.

The nonwoven fabric may be formed by cutting a stabilized first carbon fiber into short fibers; A carding process of carding the first fibrous carbon fiber; A cross lapping step of cross-lapping the second carbon fibers on the carded first carbon fibers to form a web sheet in which the first carbon fibers and the second carbon fibers are alternately stacked; And a needle punching process in which the web sheet is needle-punched and bonded to the nonwoven fabric so that a part of the fiber arrangement of the first carbon fiber and the second carbon fiber has a three-dimensional random structure.

In addition, the first carbon fibers may be based on cellulose-based fibers, and the second carbon fibers may be formed of pitch-based carbon fibers.

At this time, the second carbon fiber may be irradiated at a temperature of 280 ° C to 320 ° C for 45 minutes to 75 minutes and irradiated at 280 ° C.

Further, the activation step may be carried out at a heating rate of 26 ° C / min to 30 ° C / min for 26 to 30 minutes to reach a temperature range of 800 ° C to 900 ° C.

Also, in the nonwoven fabric, fine pores may be generated on the first carbon fibers that have undergone the activation step, and mesopores may be generated on the second carbon fibers.

The method for producing a composite activated carbon fiber nonwoven fabric according to the present invention having the above-described constitution has the following effects.

First, heterogeneous carbon fibers composed of different components are combined to provide selective and comprehensive adsorption.

Also, by controlling the content of heterogeneous carbon fiber, it is possible to easily control the size, generation degree and distribution degree of the pores according to the application.

On the other hand, the effects of the present invention are not limited to the effects mentioned above, and other effects not mentioned can be clearly understood by those skilled in the art from the description of the claims.

1 and 2 are views showing a flow of a process of a method for producing a composite activated carbon fiber nonwoven fabric according to an embodiment of the present invention.
FIG. 3 is a graph showing the specific surface area of activated carbon fibers according to the immersion time in the immersion process according to an embodiment of the present invention.
FIG. 4 is a graph showing the specific surface area and tensile strength of carbon fibers during activation according to the heat treatment temperature in the stabilization step according to an embodiment of the present invention. FIG.
FIG. 5 is a graph showing the yield of carbon fibers and the sharpness of micro pores according to the activation temperature in the activation step according to an embodiment of the present invention. FIG.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, an embodiment of the present invention in which the object of the present invention can be specifically realized will be described with reference to the accompanying drawings. In describing the present embodiment, the same names and the same symbols are used for the same components, and further description thereof will be omitted.

Further, in describing the present embodiment, the configuration shown in the drawings is only an example for helping understanding of the detailed description, and thus the scope of the right is not limited.

As shown in FIGS. 1 and 2, the method for producing a composite activated carbon fiber nonwoven fabric according to the present embodiment includes a pretreatment step S1, a stabilization step S2, a nonwoven formation step S3 and an activation step S4 .

First, the pretreatment step (S1) is a step of chemically treating the first carbon fiber to be a base material of the composite activated carbon fiber for a subsequent step, and the first carbon fiber is immersed in a chemical aqueous solution having an acidic or basic atmosphere for a predetermined time It can be a deposition step.

Here, the first carbon fiber may be a carbon fiber formed based on cellulose-based fibers.

Cellulose-based fibers have cellulose as a main component, and cellulose has a molecular structure in which carbon, hydrogen, and oxygen are bonded.

Since the cellulose fibers show rapid reactivity at a relatively low temperature in the pretreatment step S1, they are effective in preventing the damage of the material and increasing the production speed. It is possible to reduce the amount of waste to be discharged.

In addition, since the cellulose fiber is the most expensive fiber among all the fibers, whether natural or artificial, the production cost can be largely reduced as compared with the conventional PAN fiber.

Returning to the main point, the pretreatment step S1 is a step for promoting the formation of micropores on the surface of the first carbon fiber in the activation step S4 to be performed later, whereby ions of the chemical solution are uniformly dispersed on the first carbon fiber And then, in the activation step (S4), the bonding of the carbon and the ions of the chemical solution is facilitated, so that micropores can be more actively generated on the surface of the first carbon fiber.

The pretreatment step S1 may include the immersion step S1-1 and the washing and drying step S1-2 as shown in FIG. 2 in detail.

The immersion step (S1-1) can be carried out by immersing the first carbon fiber in a chemical aqueous solution containing any one of sulfuric acid, nitric acid, phosphoric acid, sodium chloride, potassium permanganate, and potassium carbonate.

In this case, the immersion time may be from 45 minutes to 75 minutes. As mentioned above, ionized sulfur, nitrogen, phosphorus, sodium and potassium ions in the chemical aqueous solution can be uniformly adsorbed on the surface of the first carbon fiber .

As shown in FIG. 3, the immersion time showed the highest specific surface area (relative micro pore formation) when the process proceeded from 45 minutes to 75 minutes, and after the activation step (S4) This is ideal.

However, in the deposition process (S1-1) according to the present embodiment, the process time from 45 minutes to 75 minutes is an ideal process time in terms of the normal efficiency, and the process time of the deposition process (S1-1) It is not necessarily limited to the above time.

That is, depending on the temperature and environmental requirements of the aqueous solution, the immersion time can be changed as much as possible. In addition, if the pre-treatment of the first carbon fiber after the immersion process (S1-1) is incomplete, It should be noted that by stepping on it can be done in a fluid way so that sufficient pretreatment can take place.

Meanwhile, the washing and drying process (S1-2) is a process of washing and drying the first carbon fiber immersed in the aqueous solution, wherein the first carbon fiber is washed using distilled water and dried at a temperature of 70 ° C or lower Lt; / RTI >

At this time, drying at a temperature of 70 ° C or below is advantageous in that, when dried at a temperature of 70 ° C or higher, ions adsorbed on the first carbon fiber are fixed to the surface of the fiber, and micro pores are generated due to the bonding force between the ions and carbon. .

Next, the stabilization step (S2) is a step of stabilizing the pretreated first carbon fiber by heat treatment, and may be carried out at a temperature range of 260 to 280 DEG C for 45 to 75 minutes.

The stabilization step S2 is a step required to convert the first carbon fiber into the activated carbon fiber through the activation step S4. The carbon fiber is removed from the components constituting the carbon fiber through the heat treatment , And the durability can be added so that the carbon fiber can withstand high temperature heat in the activation step S4.

Here, the reason why the stabilization step (S2) is performed for 45 minutes to 75 minutes in the temperature range of 260 占 폚 to 280 占 폚 may be as follows.

As shown in FIG. 4, when the stabilization step (S2) proceeds in the temperature range of 200 ° C. to 240 ° C., generation of micropores upon activation may be difficult due to unstable stabilization of the first carbon fiber.

On the other hand, when the stabilization step S2 is carried out in the temperature range of 290 ° C to 300 ° C, the tensile strength of the fiber is drastically lowered, which may cause various problems in producing a nonwoven fabric and a pleated filter .

That is, since the stabilization step (S2) according to this embodiment can sufficiently bring out the cyclization reaction of the first carbon fiber when the temperature is in the range of 260 ° C to 280 ° C, a high production efficiency and a stable micropore Yield can be obtained.

In the stabilization step S2 according to the present embodiment, similarly to the pre-processing step S1, if the first carbon fiber is not sufficiently heat-treated, the time of the stabilization step S2 may be flexibly adjusted, It can be repeatedly performed so that sufficient heat treatment can be performed by passing through step S2.

Subsequently, in the non-woven forming step (S3), the stabilized first carbon fibers may be mixed with the second carbon fibers to form a nonwoven fabric.

Here, the second carbon fiber is a second precursor having a component different from that of the first carbon fiber, and may be composed of pitch-based carbon fibers.

In this case, in the case of the second carbon fiber composed of the pitch-based carbon fiber, it may be a carbon fiber that has been pretreated separately as the first carbon fiber. In the case of the pretreatment, The conditions may be different from the preprocessing step S1.

Such pitch-based carbon fibers are carbon fibers obtained from petroleum coal-based hydrocarbon residues, which have a high elastic modulus and strength and can obtain a wide range of properties and have an advantage in that they are comparatively inexpensive in cost as in the above-mentioned cellulose-based carbon fibers.

When the nonwoven fabric is formed by mixing the second carbon fibers constituted of the pitch-based carbon fibers with the first carbon fibers constituted of the cellulose-based carbon fibers, the following advantages are obtained.

First, there is an economical advantage that the activated carbon fiber nonwoven fabric can be produced at a very low production cost, compared with the conventional production of filter nonwoven fabric using only PAN-based carbon fiber.

In addition, it is possible to increase the yield of the cellulose-based carbon fiber to a sufficient level by introducing it into the cellulose-based carbon fiber which is relatively inexpensive but relatively low in yield as compared with the PAN-based carbon fiber.

Further, there is an additional advantage that the activated carbon fiber nonwoven fabric having various pore sizes and distribution can be produced by controlling the mixing ratio of the first carbon fiber and the second carbon fiber.

However, in the present embodiment, the second carbon fibers are not necessarily composed of pitch carbon fibers, and it is specified that various kinds of carbon fibers can be applied as long as the above-mentioned effects can be derived.

2, the cutting process S3-1, the carding process S3-2, the cross-lapping process S3-3, and the needle punching process S3-3, as shown in FIG. 2, And the process (S3-4).

The cutting process (S3-1) is a process of cutting the stabilized first carbon fiber through the stabilization step (S2) to shorten the fiber, and cut the first carbon fiber into an appropriate size to form the nonwoven fabric.

The carding process (S3-2) is a process of carding the first carbon fibers that have become short fibers through a cutting process (S3-1). Here, the carding refers to separation and alignment of tangled fibers one by one, The fiber bundles are collected and prepared in the form of cotton to produce a nonwoven fabric. In this process, the impurities contained in the first carbon fiber can be removed.

The cross-lapping step S3-3 is a step of cross-lapping the second carbon fiber to the first carbon fiber carded through the carding step S3-2, wherein the cross- The fibers can be made into web sheets alternately superimposed.

At this time, the second carbon fiber may be subjected to a heat treatment at a temperature range of 280 ° C to 320 ° C for 45 minutes to 75 minutes, and the carbon fiber spun at 280 ° C may be cross-wrapsped with the first carbon fiber. (Here, radiation is a general term meaning "spinning of fibers", which does not have a special technical meaning.)

In the needle punching process (S3-4), the web sheet formed through the cross-lapping process (S3-3) is needle punched so that a part of the fiber arrangement of the first carbon fiber and the second carbon fiber has a three-dimensional random structure Nonwoven fabric.

Here, the needle punching refers to a process in which a plurality of web sheets are bonded to each other by nonwoven fabrication by passing a needle having a barb formed thereon on two or more overlapping web sheets.

Through the needle punching process (S3-4), the fiber arrangement of the interface between the first carbon fiber and the second carbon fiber is irregularly three-dimensionally tangled with each other, so that the web sheets are bonded to one nonwoven fabric Lt; / RTI >

More specifically, the fiber arrangement of the first carbon fiber and the second carbon fiber, which are located at the portion where the needle reciprocates in the fiber array of the web sheet, can be entangled with each other in the upward, downward, or upward and downward directions to have a three-dimensional random structure.

As described above, the nonwoven fabric produced through the present embodiment not only forms a composite fiber layer in which the first carbon fibers and the second carbon fibers are superimposed on each other, but also the material properties of the first carbon fibers and the second carbon fibers are sufficiently intertwined .

In the activation step S4, a space in which the ions of the chemical solution adsorbed on the carbon fibers react with carbon sufficiently through the pretreatment step S1 may be formed.

Meanwhile, the ratio of the second carbon fibers injected into the first carbon fibers in the non-woven forming process (S3) according to the present embodiment may be variously mixed within a range of 1: 9 to 9: 1, It depends on the characteristics of the nonwoven fabric, and the selective / comprehensive adsorption degree can be calculated and applied according to the application.

In addition, in the nonwoven fabricating process (S3) according to the present embodiment, ordinary short fibers may be added and mixed in addition to the first carbon fibers and the second carbon fibers. In addition, the nonwoven fabric may be used as a filter Can be applied.

Next, in the activating step (S4), the nonwoven fabric produced through the above-described nonwoven fabricating step (S3) is heated at a predetermined heating rate for a predetermined time to activate the first to second carbon fibers constituting the nonwoven fabric .

Micropores or macropores of micropores are formed on the first carbon fibers of the nonwoven fabric after the activation step S4, and mesopores may be generated on the second carbon fibers.

Herein, the micropores refer to micropores having a pore size of 2 nm or less, the macron pores are micropores having a pore size of 50 nm or more, and the mesopore refers to micropores having a pore size of 2 nm or more and 50 nm or less.

As described above, since the composite activated carbon fiber nonwoven fabric according to the present embodiment is composed of heterogeneous carbon fibers composed of different components, micropores having various sizes can be formed complexly upon activation.

The reason why such complex micropores are important is as follows.

First, micro pores have the advantage of high adsorption and filtration ability because they have high relative surface area and can adsorb fine pollutants, but they are too small to be easily clogged with pore openings.

On the other hand, the macron pore has a high adsorption rate and high air permeability, but has a disadvantage in that the relative surface area is low and the pore size is too large to cause an efficient catalytic reaction.

In case of the mesopore pore, the pore is located between the micro pore and the macron pore mentioned above. The length and disadvantage of the pore are also intermediate between the micro pore and the macron pore.

Meanwhile, in the case of the nonwoven fabric according to the present invention, as described above, since heterogeneous materials composed of different components are mixed, micro, mesoporous, and macroscopic pores can be produced in a complex manner due to the nature of the material during activation.

Accordingly, the advantages of the micro pores are further enhanced through the interaction of micro pores having various sizes, and the drawbacks can be compensated.

That is, since various sizes of micropores are produced in a complex manner, selective and comprehensive adsorption of contaminants may be possible.

Further, by controlling the content of different kinds of carbon fibers in the manufacturing process, the size, the degree of production, and the degree of distribution of pores can be easily controlled according to the use.

On the other hand, the activation step S4 may be carried out for 26 to 30 minutes at a heating rate of 26 [deg.] C / min to 30 [deg.] C / min until a temperature range of 800 [deg.] C to 900 [deg.] C is reached.

Through this activation step (S4), the activation reaction is promoted at the fiber surfaces of the first carbon fiber and the second carbon fiber, and micro pores can be generated.

As described above, the temperature raising rate, the heating time, and the reaching temperature in the activation step S4 according to the present embodiment may be as follows.

First, when the nonwoven fabric is activated so as to reach the temperature range of 600 ° C to 700 ° C as shown in FIG. 5 and the following Table 1, a high yield of 40% to 60% can be obtained.

On the other hand, when the nonwoven fabric is activated to reach the temperature range of 800 ° C to 900 ° C, the yield is in the range of 30% to 40%, which is insufficient, but the micropores are most clearly generated.

As described above, the yield and the degree of clarity of micropores may be separated according to the temperature of activation. When the composite activated carbon fiber nonwoven fabric according to the present invention is used as an adsorbent material for a filter, the micropores are most clearly formed This adsorption material can be said to be most faithful to the purpose.

Therefore, in the activating step S4 according to the present embodiment, it can be said that the temperature at which the activation reaches the temperature range of 800 ° C to 900 ° C is most suitable.

On the other hand, when the reaching temperature of activation exceeds 1000 캜, the yield is not high, and it is not reasonable from the viewpoint of production cost and energy consumption.

In addition, an inert gas, such as an activation step (S4) is water vapor (H ₂ O) atmosphere or a gaseous nitrogen (N ₂₎ atmosphere, and further carbon dioxide (CO ₂₎ and nitrogen gas (N ₂₎ according to this embodiment is It can be carried out under a mixed atmosphere.

When the above-mentioned gas is supplied in the activating step S4, the gases come into contact with the surface of the fine pores formed by the ions of the chemical solution adsorbed on the surface of the carbon fiber through the pretreatment step S1, Can be further promoted.

As a result, the mesopores and macromolecules described above can be further developed in the micropores generated through the activation step (S4), and thus the specific surface area of the composite activated carbon fiber nonwoven fabric can be further increased.

It will be apparent to those skilled in the art that the present invention can be embodied in other specific forms without departing from the spirit or scope of the invention as defined in the appended claims. It is obvious to them.

Therefore, the above-described embodiments are to be considered as illustrative rather than restrictive, and the present invention is not limited to the above description, but may be modified within the scope of the appended claims and equivalents thereof.

S1: preprocessing step
S1-1: Deposition process
S1-2: Cleaning and drying process
S2: Stabilization step
S3: non-woven forming step
S3-1: Cutting process
S3-2: Carding process
S3-3: Crosslapping process
S3-4: needle punching process
S4: activation step

Claims

A pretreatment step of chemically pretreating the first carbon fiber based on cellulose fibers;
Stabilizing the pretreated first carbon fiber by heat treatment to stabilize the first carbon fiber;
Wherein the carbon fiber is formed of pitch carbon fibers on the first carbon fiber stabilized through the pretreatment step and the stabilization step and is subjected to heat treatment at a temperature range of 280 ° C to 320 ° C for 45 minutes to 75 minutes, Forming a nonwoven fabric by mixing the first carbon fiber and the second carbon fiber; And
And activating the nonwoven fabric by heating the nonwoven fabric at a heating rate of 26 DEG C / min to 30 DEG C / min for 26 to 30 minutes to reach a temperature range of 800 DEG C to 900 DEG C,
A method for producing a composite activated carbon fiber nonwoven fabric.

The method according to claim 1,
The pre-
Wherein the first carbon fiber is immersed in an aqueous solution containing one of sulfuric acid, nitric acid, phosphoric acid, sodium chloride, potassium permanganate and calcium carbonate for 45 to 75 minutes.
A method for producing a composite activated carbon fiber nonwoven fabric.

3. The method of claim 2,
The pre-
And washing and drying the first carbon fiber that has been immersed in the aqueous solution.
A method for producing a composite activated carbon fiber nonwoven fabric.

The method according to claim 1,
Wherein the stabilizing step comprises:
Gt; to < RTI ID = 0.0 > 280 C < / RTI > for 45 to 75 minutes.
A method for producing a composite activated carbon fiber nonwoven fabric.

The method according to claim 1,
The non-
A cutting step of cutting the stabilized first carbon fiber into short fibers;
A carding process of carding the first fibrous carbon fiber;
A cross lapping step of cross-lapping the second carbon fibers on the carded first carbon fibers to form a web sheet in which the first carbon fibers and the second carbon fibers are alternately stacked; And
And a needle punching step of needle punching the web sheet to bind the web sheet to the nonwoven fabric so that a part of the fiber arrangement of the first carbon fiber and the second carbon fiber has a three-dimensional random structure.
A method for producing a composite activated carbon fiber nonwoven fabric.

delete

The method according to claim 1,
The non-
Characterized in that fine pores are formed on the first carbon fibers after the activation step and mesopores are generated on the second carbon fibers.
A method for producing a composite activated carbon fiber nonwoven fabric.