KR102151547B1 - Rubber composites including carbon nano fiber with improved dispersibility and method for manufacturing the same - Google Patents

Abstract

The present invention relates to a rubber composite including carbon nanofibers with improved dispersibility and a method of manufacturing the same. In the present invention, as the carbon nanofiber structure and ethylene propylene diene monomer (EPDM) are modified with acid and alkyl amine to improve dispersibility and long-term dispersion stability, properties such as elongation, tensile strength, heat resistance, and permanent compression reduction rate are improved. It provides a rubber composite and a method of manufacturing the same.

Description

Rubber composite containing carbon nanofibers with improved dispersibility, and manufacturing method thereof {RUBBER COMPOSITES INCLUDING CARBON NANO FIBER WITH IMPROVED DISPERSIBILITY AND METHOD FOR MANUFACTURING THE SAME}

The present invention relates to a rubber composite including carbon nanofibers with improved dispersibility and a method of manufacturing the same.

With the development of the automobile industry, various materials have been developed for the purpose of improving fuel economy and performance, and to improve durability, mechanical or physical properties, as well as weight reduction and miniaturization of a vehicle body. For example, by adding nano-sized fillers to rubber, which is a major material of automobile parts, weight reduction, durability, heat resistance, thermal conductivity, heat dissipation, and the like are improved. In particular, rubber is highly utilized as a major material for various machines, instruments, and products as well as automobile parts, and various attempts to improve the physical properties of rubber are continuing.

For example, Korean Patent Registration No. 10-0705784 contains 0.1 to 50 parts by weight of carbon nanotubes and 1 to 10 parts by weight of wood powder per 100 parts by weight of raw rubber, thereby improving mechanical properties and heat resistance of the rubber. The composition is disclosed. In addition, the Republic of Korea Patent Registration No. 10-1422829 contains 100 parts by weight of raw rubber, 10 to 90 parts by weight of titanium dioxide, and 1 to 50 parts by weight of carbon nanofibers, so that the rubber composition for tire tread with improved reinforcing performance and physical properties It is starting.

On the other hand, as disclosed in the above patent, even when nano fillers such as carbon nanotubes and carbon nanofibers are added, there is a problem in that aggregation occurs or precipitation occurs due to low dispersibility. That is, despite the addition of nano fillers such as carbon nanotubes and carbon nanofibers, there is a problem in that properties such as elongation, durability, heat resistance, thermal conductivity, heat dissipation properties, and mechanical properties of rubber are not sufficiently improved.

In order to solve this problem, Korean Patent Registration No. 10-0665130 discloses that 0.1 to 5.0 parts by weight of long-grown carbon nanofibers are physically mixed and dispersed as a reinforcing agent with respect to 100 parts by weight of an epoxy matrix without the use of a solvent. Disclosed is a method of preparing an epoxy nanocomposite material containing vapor-grown carbon nanofibers with improved dispersibility by adding and curing a curing agent to a mixture, and a nanocomposite material prepared thereby. However, in the case of the above registered patent, the method of mixing it with a polymer resin, not the carbon nanofiber itself, has a problem that only temporary dispersibility is improved and the dispersibility of the carbon nanofiber itself is still low.

Korean Patent Registration No. 10-0705784 Korean Patent Registration No. 10-1422829 Korean Patent Registration No. 10-0665130

The first object of the present invention is to provide a rubber composite with improved properties such as elongation, tensile strength, heat resistance, and permanent compression reduction rate by including carbon nanofibers with improved dispersibility and long-term dispersion safety by being modified with an acid and an alkyl amine. Is in.

The second object of the present invention is to form a carbon nanofiber structure with improved dispersibility and long-term dispersion stability by acid treatment of carbon nanofibers followed by alkyl amine treatment, and then by mixing it with ethylene propylene diene monomer, elongation and tensile strength , To provide a manufacturing method capable of manufacturing a rubber composite having improved properties such as heat resistance and permanent compression reduction rate.

The object of the present invention is not limited to the technical problem as described above, and another technical problem may be derived from the following description.

In order to achieve the first object, the present invention includes an ethylene propylene diene monomer (EPDM) and a carbon nanofiber structure, wherein the carbon nanofiber structure is a carbon nanofiber modified with an acid and an alkyl amine, and the alkyl amine is a carbon number It provides a rubber composite containing 5 to 20 carbon nanofibers with improved dispersibility.

The alkyl amine may include an alkyl amine having 5 to 10 carbon atoms and an alkyl amine having 15 to 20 carbon atoms in a weight ratio of 1:5 to 10.

The acid may include at least one selected from the group consisting of nitric acid and sulfuric acid.

The carbon nanofiber structure may be a carbon nanofiber modified with an acid and an alkyl amine to form a peptide bond on the surface.

The rubber composite may include 0.5 to 7 parts by weight of the carbon nanofiber structure based on 100 parts by weight of the ethylene propylene diene monomer.

The rubber composite may further include 1H,1H,2H,2H-perfluorodecanethiol (1H,1H,2H,2H-perfluorodecanethiol).

The rubber composite may include 0.5 to 7 parts by weight of the carbon nanofiber structure and 0.1 to 3 parts by weight of 1H,1H,2H,2H-perfluorodecanethiol based on 100 parts by weight of the ethylene propylene diene monomer.

In order to achieve the second object, the present invention provides a first step of acid-treated carbon nanofibers to form acid-treated carbon nanofibers, and a carbon nanofiber structure is formed by treating the acid-treated carbon nanofibers with an alkyl amine. A second step of forming and a third step of mixing the carbon nanofiber structure and ethylene propylene diene monomer (EPDM), wherein the carbon nanofiber structure is a carbon nanofiber modified with an acid and an alkyl amine, and the alkyl amine is It provides a method for producing a rubber composite containing carbon nanofibers having 5 to 20 carbon atoms and improved dispersibility.

The first step may be carried out at 75 ~ 85 ℃.

The second step may be performed at 70 ~ 80 ℃.

In the third step, 1H,1H,2H,2H-perfluorodecanethiol (1H,1H,2H,2H-perfluorodecanethiol) may be further mixed.

As the rubber composite of the present invention includes a carbon nanofiber structure having improved dispersibility and long-term dispersion stability by being modified with an acid and an alkyl amine, properties such as elongation, tensile strength, heat resistance, and permanent compression reduction rate may be improved.

In particular, by including an alkyl amine having 5 to 10 carbon atoms and an alkyl amine having 15 to 20 carbon atoms in a weight ratio of 1: 5 to 10 as an alkyl amine modifying carbon nanofibers, dispersibility and long-term dispersion stability can be further improved. have. As the dispersibility and long-term dispersion stability of the carbon nanofibers are improved as described above, properties such as elongation, tensile strength, heat resistance, and permanent compression reduction rate of the rubber composite may be further improved.

The manufacturing method of the rubber composite of the present invention is to prepare a carbon nanofiber structure with improved dispersibility and long-term dispersion stability by acid treatment of carbon nanofibers and then treatment with alkyl amine, and mixing this with ethylene propylene diene monomer, elongation, A rubber composite with improved properties such as tensile strength, heat resistance, and permanent compression reduction rate can be manufactured. In particular, as an alkyl amine that modifies carbon nanofibers, an alkyl amine having 5 to 10 carbon atoms and an alkyl amine having 15 to 20 carbon atoms are included in a weight ratio of 1:5 to 10, and acid treatment and alkyl amine treatment are specified for carbon nanofibers. By carrying out at temperature, the dispersibility and long-term dispersion stability can be further improved. Accordingly, properties such as elongation, tensile strength, heat resistance, and permanent compression reduction rate of the rubber composite may be further improved.

1 is a schematic view of a reaction mechanism for forming a carbon nanofiber structure by modifying a carbon nanofiber with an acid and an alkyl amine.
2 is a carbon nanofiber of Comparative Example 1 (left), a carbon nanofiber acid-treated according to (1) of Example 5 (middle), and a carbon nanofiber structure treated with an alkyl amine according to (2) of Example 5 (Right) shows the XPS analysis results.
3 is a view showing a state immediately after preparation of a dispersion containing the carbon nanofiber structure of Example 5 and the dispersion containing the carbon nanofiber of Comparative Example 1.
4 is a view showing a state after 20 days have elapsed after preparing the dispersion containing the carbon nanofiber structure of Example 5 and the dispersion containing the carbon nanofiber of Comparative Example 1.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those of ordinary skill in the art can easily implement the present invention. However, the present invention may be implemented in various different forms and is not limited to the embodiments described herein. In the drawings, parts not related to the description are omitted in order to clearly describe the present invention.

The terms or words used in the specification and claims of the present invention are not limitedly interpreted in a conventional or dictionary meaning, and the inventor can appropriately define the concept of the term in order to describe his own invention in the best way. Based on the principle, it should be interpreted as a meaning and concept consistent with the technical idea of the present invention.

In the entire specification of the present invention, when a certain part "includes" a certain component, it means that other components may be further included rather than excluding other components unless otherwise stated. .

In the entire specification of the present invention, "A and/or B" means A or B, or A and B.

Hereinafter, the present invention has been described in detail, but the present invention is not limited thereto.

In the present invention, a rubber composite including carbon nanofibers with improved dispersibility is provided.

In an embodiment of the present invention, an ethylene propylene diene monomer (EPDM) and a carbon nanofiber structure are included, wherein the carbon nanofiber structure is a carbon nanofiber modified with an acid and an alkyl amine, and the alkyl amine has 5 to 20 carbon atoms, To provide a rubber composite.

In this embodiment, a carbon nanofiber structure having improved dispersibility and long-term dispersion stability may be formed by modifying the carbon nanofibers with an acid and an alkyl amine. Accordingly, the rubber composite of this embodiment may have properties such as excellent elongation, tensile strength, heat resistance, and permanent compression reduction rate. In this case, heat resistance is a property to withstand heat and may mean aging resistance, but is not limited thereto.

Ethylene propylene diene monomer (EPDM) is a terpolymer in which ethylene, propylene, and diene are irregularly bound, and has excellent cold resistance, weather resistance, insulation resistance, and ozone resistance. The ethylene and propylene in the ethylene propylene diene monomer can have various ratios. The ethylene propylene diene monomer of the present embodiment may contain ethylene in an amount of 50 to 60% by weight, but is not limited thereto.

If less than 50% by weight of ethylene is included based on the total weight of the ethylene propylene diene monomer of the present embodiment, there may be a problem in that the flexibility of the rubber composite decreases. On the other hand, when ethylene is included in excess of 60% by weight based on the total weight of the ethylene propylene diene monomer of the present embodiment, there may be a problem of increasing the hardness.

The carbon nanofiber structure is a carbon nanofiber modified with an acid and an alkyl amine, and may have improved dispersibility and long-term dispersion stability than conventional carbon nanofibers. 1 schematically shows the mechanism of a reaction for forming a carbon nanofiber structure by modifying a carbon nanofiber with an acid and an alkyl amine.

As shown in FIG. 1, the carbon nanofiber structure of this embodiment is formed by acid treatment of carbon nanofibers to form acid-treated carbon nanofibers, and then treatment of the acid-treated carbon nanofibers with alkyl amine. I can. That is, the carbon nanofiber structure of the present embodiment may be obtained by first modifying carbon nanofibers with an acid and then secondly modifying them with an alkyl amine.

As shown in FIG. 1, oxygen, a hydroxyl group, and a carboxyl group may be formed in the acid-treated carbon nanofiber. The carbon nanofiber structure obtained by treating the acid-treated carbon nanofibers with an alkyl amine may be a carbon nanofiber having an oxygen, a hydroxyl group, and a peptide bond formed on the surface thereof.

The carbon nanofiber is a fibrous material having a thickness of less than 1 micrometer containing 90% or more of carbon, and may include all types of carbon nanofibers known as carbon nanofibers in this embodiment. Preferably, the carbon nanofibers of the present embodiment may have a segment shape having a diameter of about 50 nanometers and a length of about 50 micrometers, but are not limited thereto.

For example, the carbon nanofibers of this embodiment are made of nickel nitrate, copper nitrate, aluminum nitrate, ammonium molybdate, and ammonium carbonate. The resulting catalyst may be prepared by growing the CVD (chemical vapor deposition) method, but is not limited thereto.

In more detail, the carbon nanofibers of the present embodiment may be manufactured according to the following, but are not limited thereto.

① Prepare the first solution by adding 3 g of a mixture of nickel nitrate and copper nitrate in a weight ratio of 8: 2 to 50 mL of distilled water. ② To prepare a second solution by adding 0.1 M aluminum nitrate to 50 mL of distilled water, ③ 1.25 g of ammonium molybdenumate and 25 mL of distilled water were mixed to prepare a third solution, and then the first solution, the second solution, and the third solution were put into a first separatory funnel and mixed. ④ 40 g of ammonium carbonate and 120 mL of distilled water were added to prepare a fourth solution, and then put into a second separatory funnel. ⑤ 100 mL of distilled water was added to a beaker, and the solution of the first separatory funnel and the solution of the second separatory funnel were slowly added while stirring. ⑥ After stirring for about 1 hour, the catalyst was prepared by filtration, drying and grinding. ⑦ The catalyst prepared according to the above was grown by the CVD method to prepare carbon nanofibers.

At this time, the CVD method is a first step of heating at room temperature to about 600° C. while flowing nitrogen gas at 500 sccm for about 1 hour after putting the catalyst in the CVD apparatus, nitrogen gas 500 sccm and hydrogen at about 600° C. for about 30 minutes. The second step of flowing 500 sccm of gas, a third step of flowing 100 sccm of hydrogen gas, 400 sccm of ethene (C ₂ H ₄ ) gas at about 600° C. for about 1 hour, and the fourth cooling to room temperature while flowing 500 sccm of nitrogen gas It may be implemented according to the steps, but is not limited thereto.

The acid may include at least one selected from the group consisting of nitric acid and sulfuric acid. Preferably, the acid may include nitric acid and sulfuric acid, but is not limited thereto.

The alkyl amine may have 5 to 20 carbon atoms. Preferably, the alkyl amine of this embodiment may be the same as the following Formula 1. In Formula 1, n may be 3 to 18, and when n is 3, the number of carbon atoms of the alkyl amine may be 5, and when n is 18, the number of carbon atoms of the alkyl amine may be 20.

[Formula 1]

H ₃ C-[CH ₂ ] _n -CH ₂ -NH ₂

If the number of carbon atoms of the alkyl amine is less than 5, the effect of improving the dispersibility and long-term dispersion stability of the carbon nanofiber structure may be insignificant. On the other hand, when the number of carbon atoms of the alkyl amine exceeds 20, the mass of the carbon nanofiber structure itself increases, so that dispersibility and long-term dispersion stability may be significantly reduced.

For example, in this embodiment, the alkyl amine having 5 to 20 carbon atoms is pentyl amine, hexyl amine, heptyl amine, octyl amine, nonyl amine, nonyl amine, decyl amine ( Decylamine), Undecylamine, Dodecylamine, Tridecylamine, Tetradecylamine, Pentadecylamine, Hexadecylamine, Hexadecylamine, Heptadecylamine ), octadecylamine, nonadecylamine , and one or more selected from the group consisting of icosylamine, but are not limited thereto.

In this embodiment, as the alkyl amine, by including an alkyl amine having 5 to 10 carbon atoms and an alkyl amine having 15 to 20 carbon atoms in a weight ratio of 1: 5 to 10, preferably in a weight ratio of 1: 7 to 8, carbon nanofiber structure Dispersibility and long-term dispersion stability can be remarkably improved. If the alkyl amine of the present embodiment does not satisfy the above mixing range, the effect of improving dispersibility and long-term dispersion stability may be insignificant.

The rubber composite of the present embodiment may include 0.5 to 7 parts by weight, preferably 1 to 5 parts by weight, and more preferably 2 to 3 parts by weight, of a carbon nanofiber structure based on 100 parts by weight of the ethylene propylene diene monomer.

If the rubber composite of this example contains less than 0.5 parts by weight of a carbon nanofiber structure with respect to 100 parts by weight of ethylene propylene diene monomer, the elongation, tensile strength, heat resistance, and permanent compression reduction rate of the rubber composite are not sufficiently improved. There may be problems that cannot be done. On the other hand, when the rubber composite of this example contains more than 7 parts by weight of a carbon nanofiber structure with respect to 100 parts by weight of ethylene propylene diene monomer, the structure inside the rubber composite is not dense, and elongation, tensile strength, heat resistance, and permanent compression There may be a problem that the reduction rate is rather lowered.

The rubber composite of this embodiment may further include 1H,1H,2H,2H-perfluorodecanethiol (1H,1H,2H,2H-perfluorodecanethiol). The 1H,1H,2H,2H-perfluorodecanethiol is also called 1,1,2,2-Tetrahydroperfluorodecanethiol, 1,1,2,2-Tetrahydroperfluorodecanethiol, and the like. The 1H,1H,2H,2H-perfluorodecanethiol improves the dispersibility and long-term dispersion stability of the carbon nanofiber structure in this embodiment, and provides properties such as elongation, tensile strength, heat resistance, and permanent compression of the rubber composite. It can be further improved.

The rubber composite of this embodiment is 0.1 to 3 parts by weight, preferably 0.5 to 2.5 parts by weight, more preferably 1 to 3 parts by weight of 1H,1H,2H,2H-perfluorodecanethiol based on 100 parts by weight of the ethylene propylene diene monomer. It may further include 1.5 parts by weight.

When the rubber composite of this embodiment further comprises 1H,1H,2H,2H-perfluorodecanethiol, the rubber composite is 0.5 to 7 parts by weight of the carbon nanofiber structure based on 100 parts by weight of the ethylene propylene diene monomer, and It may contain 0.1 to 3 parts by weight of 1H,1H,2H,2H-perfluorodecanethiol, whereby the properties of the rubber composite may be improved.

If the rubber composite of this example contains less than 0.1 parts by weight of 1H,1H,2H,2H-perfluorodecanthiol relative to 100 parts by weight of ethylene propylene diene monomer, 1H,1H,2H,2H-perfluoro Since the effect of improving the dispersibility and long-term dispersion stability of the carbon nanofiber structure by rhodecanethiol is insignificant, the effect of improving properties such as elongation, tensile strength, heat resistance, and permanent compression reduction rate of the rubber composite may be insignificant. On the other hand, in the case of including more than 3 parts by weight of 1H,1H,2H,2H-perfluorodecanthiol relative to 100 parts by weight of ethylene propylene diene monomer in the rubber composite of this example, the dispersibility of the carbon nanofiber structure, long-term There may be a problem that the dispersion stability effect is lowered and aggregation occurs.

The rubber composite of this embodiment may further include all kinds of known additives capable of improving properties such as elongation, tensile strength, heat resistance, permanent compression reduction rate, aging resistance, durability, physical properties, and mechanical properties. For example, the additives are carbon black, calcium carbonate, stearic acid, sulfur, antioxidants, oils, processing aids, crosslinking agents, crosslinking accelerators, lubricants, stabilizers, antioxidants, sunscreens, preservatives, surfactants, emulsifiers, solvents, solvents , Carbon nanotubes, graphene, graphite, ceramic, etc., but is not limited thereto.

The anti-aging agent may include bisphenol A, but is not limited thereto.

The crosslinking accelerators are zinc oxide, magnesium oxide, lead oxide, calcium hydroxide, 2-mercaptobenzothiazole (MBT), tetramethylthiuram disulfide (TMTD), zinc dibutyldithiocarbamate ( Zinc salt of Di-n-buthyldithiocarbamate; ZnBDC), Zinc salt of dimethyldithiocarbamate (ZnMDC), 4,4'-dithiodimorpholin R; Vulnoc-R, Dipenta methylene thiuram tetrasulfide and zinc dibutyl disulfide may include at least one selected from the group consisting of carbomylic acid, but is not limited thereto.

The rubber composite of this example can be applied to all fields using rubber as a material. For example, it may be applied to fields such as automobile parts, electric and electronic products, information communication portable parts, and machine parts, but is not limited thereto. Preferably, the rubber composite of the present embodiment may be used as a material for automobile parts, and more preferably, it may be used as a hose material for automobile radiators, but is not limited thereto.

The present invention provides a method of manufacturing a rubber composite including carbon nanofibers with improved dispersibility.

In one embodiment of the present invention A first step of acid-treated carbon nanofibers to form acid-treated carbon nanofibers, a second step of forming a carbon nanofiber structure by treating the acid-treated carbon nanofibers with an alkyl amine, and the carbon nanofiber structure and Including a third step of mixing ethylene propylene diene monomer (EPDM), wherein the carbon nanofiber structure is a carbon nanofiber modified with an acid and an alkyl amine, the alkyl amine has 5 to 20 carbon atoms, a method for producing a rubber composite. to provide.

In this embodiment, a carbon nanofiber structure with improved dispersibility and long-term dispersion stability may be manufactured by modifying the carbon nanofibers with an acid and an alkyl amine. Accordingly, in this embodiment, a rubber composite having excellent properties such as elongation, tensile strength, heat resistance, and permanent compression reduction rate can be manufactured.

(1) The first step of acid treatment of carbon nanofibers to form acid-treated carbon nanofibers

In the first step of this embodiment, the carbon nanofibers are acid-treated to form acid-treated carbon nanofibers. The first step of this embodiment may be performed at 75 to 85° C. for about 4 to 8 hours.

The carbon nanofiber is a fibrous material having a thickness of less than 1 micrometer containing 90% or more of carbon, and may include all types of carbon nanofibers known as carbon nanofibers in this embodiment. Preferably, the carbon nanofibers of the present embodiment may have a segment shape having a diameter of about 50 nanometers and a length of about 50 micrometers, but are not limited thereto.

For example, the carbon nanofibers of this embodiment are made of nickel nitrate, copper nitrate, aluminum nitrate, ammonium molybdate, and ammonium carbonate. The resulting catalyst may be prepared by growing the CVD (chemical vapor deposition) method, but is not limited thereto.

In more detail, the carbon nanofibers of the present embodiment may be manufactured according to the following, but are not limited thereto.

① Prepare the first solution by adding 3 g of a mixture of nickel nitrate and copper nitrate in a weight ratio of 8: 2 to 50 mL of distilled water, ② To prepare a second solution by adding 0.1 M aluminum nitrate to 50 mL of distilled water, ③ A third solution was prepared by mixing 1.25 g of ammonium molybdenate and 25 mL of distilled water, and then the first solution, the second solution, and the third solution were put into a first separatory funnel and mixed. ④ 40 g of ammonium carbonate and 120 mL of distilled water were added to prepare a fourth solution, and then put into a second separatory funnel. ⑤ 100 mL of distilled water was added to a beaker, and the solution of the first separatory funnel and the solution of the second separatory funnel were slowly added while stirring. ⑥ After stirring for about 1 hour, the catalyst was prepared by filtration, drying and grinding. ⑦ The catalyst prepared according to the above was grown by the CVD method to prepare carbon nanofibers.

At this time, the CVD method is a first step of heating at room temperature to about 600° C. while flowing nitrogen gas at 500 sccm for about 1 hour after putting the catalyst in the CVD apparatus, nitrogen gas 500 sccm and hydrogen at about 600° C. for about 30 minutes. The second step of flowing 500 sccm of gas, a third step of flowing 100 sccm of hydrogen gas, 400 sccm of ethene (C ₂ H ₄ ) gas at about 600° C. for about 1 hour, and the fourth cooling to room temperature while flowing 500 sccm of nitrogen gas It may be implemented according to the steps, but is not limited thereto.

The acid may include at least one selected from the group consisting of nitric acid and sulfuric acid. Preferably, the acid may include nitric acid and sulfuric acid, but is not limited thereto. A separate solvent may be used for sufficient reaction or mixing of the carbon nanofibers and the acid, and any known solvent may be applied without limitation.

The first step of this embodiment may be carried out at about 75 to 85 °C, preferably 78 to 82 °C. If the first step of the present embodiment is carried out at a temperature of less than 75° C., the reaction between the carbon nanofibers and the acid does not occur sufficiently, so that the dispersibility and long-term dispersion stability of the carbon nanotube structure may be deteriorated. . On the other hand, when the first step of the present embodiment is carried out at a temperature exceeding 85° C., aggregation between carbon nanofibers or by-products may occur, and thus there may be a problem that is not efficient.

The first step of this embodiment may be carried out at 75 to 85° C. for about 4 to 8 hours, preferably 5 to 7 hours, and more preferably 6 hours. If the first step of the present embodiment is carried out for less than 4 hours, the reaction between the carbon nanofibers and the acid does not sufficiently occur, and thus the dispersibility and long-term dispersion stability of the carbon nanotube structure may be deteriorated. On the other hand, when the first step of the present embodiment is carried out for more than 8 hours, aggregation between carbon nanofibers or by-products may occur, and thus there may be a problem that is not efficient.

In the first step of the present embodiment, separate stirring, vibration, ultrasonic treatment, etc. may be performed for the reaction of the carbon nanofibers and the acid, but is not limited thereto. In addition, in the first step of the present embodiment, continuous heating may be performed to maintain the temperature.

(2) The second step of forming a carbon nanofiber structure by treating an acid-treated carbon nanofiber with an alkyl amine

In the second step of the present embodiment, the acid-treated carbon nanofibers may be treated with an alkyl amine to form a carbon nanofiber structure.

The alkyl amine may have 5 to 20 carbon atoms. Preferably, the alkyl amine of the present embodiment may be the same as Formula 1. In Formula 1, n may be 3 to 18, and when n is 3, the number of carbon atoms of the alkyl amine may be 5, and when n is 18, the number of carbon atoms of the alkyl amine may be 20.

If the number of carbon atoms of the alkyl amine is less than 5, the effect of improving the dispersibility and long-term dispersion stability of the carbon nanofiber structure may be insignificant. On the other hand, when the number of carbon atoms of the alkyl amine exceeds 20, the mass of the carbon nanofiber structure itself increases, so that dispersibility and long-term dispersion stability may be significantly reduced.

For example, in this embodiment, the alkyl amine having 5 to 10 carbon atoms is pentyl amine, hexyl amine, heptyl amine, octyl amine, nonyl amine, nonyl amine, decyl amine ( Decylamine), Undecylamine, Dodecylamine, Tridecylamine, Tetradecylamine, Pentadecylamine, Hexadecylamine, Hexadecylamine, Heptadecylamine ), octadecylamine, nonadecylamine , and one or more selected from the group consisting of icosylamine, but are not limited thereto.

In this embodiment, as the alkyl amine, by including an alkyl amine having 5 to 10 carbon atoms and an alkyl amine having 15 to 20 carbon atoms in a weight ratio of 1: 5 to 10, preferably in a weight ratio of 1: 7 to 8, carbon nanofiber structure Dispersibility and long-term dispersion stability can be remarkably improved. If the alkyl amine of the present embodiment does not satisfy the above mixing range, the effect of improving dispersibility and long-term dispersion stability may be insignificant.

The second step of this embodiment may be performed at about 70 to 80° C. for about 20 to 28 hours.

The second step of this embodiment may be carried out at about 70 to 80 °C, preferably at 77 to 80 °C. If the second step of this embodiment is carried out at less than 70° C., the acid-treated carbon nanofibers and the alkyl amine do not react sufficiently, so that the dispersibility and long-term dispersion stability of the carbon nanofiber structure may be deteriorated. have. On the other hand, when the second step of the present embodiment is carried out at a temperature exceeding 80° C., aggregation between acid-treated carbon nanofibers occurs or by-products are generated, and thus there may be a problem that is not efficient.

The second step of this embodiment may be performed at 70 to 80° C. for about 20 to 28 hours, preferably 22 to 26 hours, and more preferably 24 hours. If the second step of this embodiment is carried out for less than 20 hours, the acid-treated carbon nanofibers and the alkyl amine do not react sufficiently, so that the dispersibility and long-term dispersion stability of the carbon nanofiber structure may be deteriorated. have. On the other hand, when the second step of the present embodiment is carried out for more than 28 hours, aggregation between the acid-treated carbon nanofibers occurs or by-products are generated, and thus there may be a problem that is not efficient.

In the second step of the present embodiment, separate stirring, vibration, ultrasonic treatment, etc. may be performed for the reaction of the acid-treated carbon nanofibers and the alkyl amine, but is not limited thereto. In addition, in the second step of the present embodiment, continuous heating may be performed to maintain the temperature.

The carbon nanofiber structures manufactured according to the first and second steps of the present embodiment are carbon nanofibers modified with an acid and an alkyl amine, and may have improved dispersibility and long-term dispersion stability than conventional carbon nanofibers.

1 is a schematic view of a reaction mechanism for forming a carbon nanofiber structure by modifying a carbon nanofiber with an acid and an alkyl amine, and the first and second steps of this embodiment follow the mechanism as shown in FIG. However, it is not limited thereto.

As shown in FIG. 1, oxygen, hydroxy groups, and carboxyl groups may be formed in the acid-treated carbon nanofibers according to the first step of this embodiment. The carbon nanofiber structure obtained by treating the acid-treated carbon nanofibers with an alkyl amine according to the second step of the present embodiment may be a carbon nanofiber having an oxygen, a hydroxyl group, and a peptide bond formed on the surface.

(3) The third step of mixing the carbon nanofiber structure and ethylene propylene diene monomer (EPDM)

In the third step of this embodiment, the carbon nanofiber structure and ethylene propylene diene monomer (EPDM) are mixed. In more detail, in the third step of the present embodiment, the carbon nanofiber structure and the ethylene propylene diene monomer are uniformly mixed and then cured into a specific shape, thereby forming a rubber composite. In the third step of the present embodiment, separate stirring, vibration, ultrasonic treatment, etc. may be performed for the reaction of the carbon nanofiber structure and the ethylene propylene diene monomer, but is not limited thereto.

The ethylene propylene diene monomer (EPDM) is a terpolymer in which ethylene, propylene, and diene are irregularly bonded, and has excellent cold resistance, weather resistance, insulation resistance, and ozone resistance. The ethylene and propylene in the ethylene propylene diene monomer have various ratios.

The ethylene propylene diene monomer of the present embodiment may contain ethylene in an amount of 50 to 60% by weight, but is not limited thereto. If less than 50% by weight of ethylene is included based on the total weight of the ethylene propylene diene monomer of the present embodiment, there may be a problem in that the flexibility of the rubber composite decreases. On the other hand, when ethylene is included in excess of 60% by weight based on the total weight of the ethylene propylene diene monomer of the present embodiment, there may be a problem of increasing the hardness.

In the third step of the present embodiment, 0.5 to 7 parts by weight of the carbon nanofiber structure, preferably 1 to 5 parts by weight, more preferably 2 to 3 parts by weight, may be included with respect to 100 parts by weight of the ethylene propylene diene monomer.

If the carbon nanofiber structure is included in an amount of less than 0.5 parts by weight based on 100 parts by weight of the ethylene propylene diene monomer in this embodiment, the elongation, tensile strength, heat resistance, and permanent compression reduction rate of the rubber composite are not sufficiently improved. There may be. On the other hand, in the present embodiment, when the carbon nanofiber structure exceeds 7 parts by weight per 100 parts by weight of ethylene propylene diene monomer, the structure inside the rubber composite is not dense, and elongation, tensile strength, heat resistance, and permanent compression reduction rate There may be a problem that the back is rather lowered.

In the third step of this embodiment, in order to improve the dispersibility and long-term dispersion stability of the carbon nanofiber structure, and to improve the properties of the rubber composite, 1H, 1H, 2H, 2H-perfluorodecanethiol (1H, 1H, 2H) , 2H-perfluorodecanethiol) may be further included.

The 1H,1H,2H,2H-perfluorodecanethiol is also called 1,1,2,2-Tetrahydroperfluorodecanethiol, 1,1,2,2-Tetrahydroperfluorodecanethiol, and the like. The 1H,1H,2H,2H-perfluorodecanethiol improves the dispersibility and long-term dispersion stability of the carbon nanofiber structure in this embodiment, and provides properties such as elongation, tensile strength, heat resistance, and permanent compression of the rubber composite. It can be further improved.

In the third step of this embodiment, 1H,1H,2H,2H-perfluorodecanthiol 0.1 to 3 parts by weight, preferably 0.5 to 2.5 parts by weight, more preferably 1 based on 100 parts by weight of the ethylene propylene diene monomer ~ 1.5 parts by weight may be further mixed.

In the third step of this embodiment, when 1H,1H,2H,2H-perfluorodecanethiol is further included, 0.5 to 7 parts by weight of the carbon nanofiber structure and 1H,1H based on 100 parts by weight of the ethylene propylene diene monomer ,2H,2H-perfluorodecanethiol may contain 0.1 to 3 parts by weight, whereby the properties of the rubber composite may be improved.

If, in this example, 1H,1H,2H,2H-perfluorodecanethiol is included in an amount of less than 0.1 parts by weight per 100 parts by weight of ethylene propylene diene monomer, 1H,1H,2H,2H-perfluorodecane The effect of improving the dispersibility and long-term dispersion stability of the carbon nanofiber structure by thiol is insignificant, and thus the effect of improving properties such as elongation, tensile strength, heat resistance, and permanent compression reduction rate of the rubber composite may be insignificant. On the other hand, in the present embodiment, when containing more than 3 parts by weight of 1H,1H,2H,2H-perfluorodecanethiol relative to 100 parts by weight of the ethylene propylene diene monomer, the dispersibility of the carbon nanofiber structure and long-term dispersion stability There may be a problem that the effect is lowered and aggregation occurs.

In the third step of this embodiment, all kinds of known additives that can improve properties such as elongation, tensile strength, heat resistance, permanent compression reduction rate, aging resistance, durability, physical properties, and mechanical properties of the rubber composite are further included. I can.

For example, the additives are carbon black, calcium carbonate, stearic acid, sulfur, antioxidants, oils, processing aids, crosslinking agents, crosslinking accelerators, lubricants, stabilizers, antioxidants, sunscreens, preservatives, surfactants, emulsifiers, solvents, solvents , Carbon nanotubes, graphene, graphite, ceramic, etc., but is not limited thereto.

The anti-aging agent may include bisphenol A, but is not limited thereto.

The crosslinking accelerators are zinc oxide, magnesium oxide, lead oxide, calcium hydroxide, 2-mercaptobenzothiazole (MBT), tetramethylthiuram disulfide (TMTD), zinc dibutyldithiocarbamate ( Zinc salt of Di-n-buthyldithiocarbamate; ZnBDC), Zinc salt of dimethyldithiocarbamate (ZnMDC), 4,4'-dithiodimorpholin R; Vulnoc-R, Dipenta methylene thiuram tetrasulfide and zinc dibutyl disulfide may include at least one selected from the group consisting of carbomylic acid, but is not limited thereto.

After mixing the carbon nanofiber structure and the ethylene propylene diene monomer according to the third step, the rubber composite may be formed by curing it in a specific shape. In this case, post-treatment such as additional compression, heat treatment, cutting, stretching, etc. may be performed, but is not limited thereto.

The method for producing a rubber composite including carbon nanofibers having improved dispersibility of the present invention includes all the contents of the rubber composite including carbon nanofibers having improved dispersibility of the present invention.

Hereinafter, through Examples, Comparative Examples, and Experimental Examples, a rubber composite including carbon nanofibers having improved dispersibility of the present invention and a method of manufacturing the same will be described in detail. Since these examples are for illustrative purposes only, the scope of the present invention is not to be construed as being limited by these examples.

[Example]

Examples 1 to 7

(1) To 2 g of carbon nanofibers, 1 g of acid mixed with sulfuric acid and nitric acid in a weight ratio of 3: 1 was added, and then stirred at a temperature of about 80° C. for about 6 hours, and then centrifuged (4000 rpm, 1 hour). ) And filtered to prepare acid-treated carbon nanofibers.

(2) Subsequently, 1 g of the alkyl amine mixed in the weight ratio of Table 1 was added to the acid-treated carbon nanofibers, respectively, and then stirred at a temperature of about 80° C. for about 24 hours, and then centrifuged (4000 rpm, 1 hour) and filtering to prepare a carbon nanofiber structure.

(3) A rubber composite was prepared by mixing the carbon nanofiber structure and ethylene propylene diene monomer obtained as described above according to Table 2 [unit: parts by weight] and then curing. As the ethylene propylene diene monomer, one containing 55% by weight of ethylene was used.

At this time, the carbon nanofibers for the production of the carbon nanofiber structure were prepared by the following method. ① Prepare the first solution by adding 3 g of a mixture of nickel nitrate and copper nitrate in a weight ratio of 8: 2 to 50 mL of distilled water, ② To prepare a second solution by adding 0.1 M aluminum nitrate to 50 mL of distilled water, ③ 1.25 g of ammonium molybdenumate and 25 mL of distilled water were mixed to prepare a third solution, and then the first solution, the second solution, and the third solution were put into a first separatory funnel and mixed. ④ 40 g of ammonium carbonate and 120 mL of distilled water were added to prepare a fourth solution, and then put into a second separatory funnel. ⑤ Next, 100 mL of distilled water was added to the beaker, and the solution of the first separatory funnel and the solution of the second separatory funnel were slowly added while stirring. ⑥ After stirring for about 1 hour, the catalyst was prepared by filtration, drying and grinding. ⑦ Thereafter, the catalyst prepared according to the above was grown using a CVD method to prepare carbon nanofibers.

The CVD was carried out as follows. First, after putting the catalyst into a CVD apparatus, nitrogen gas was flowed at 500 sccm for about 1 hour and heated to about 600° C. at room temperature, and 500 sccm of nitrogen gas and 500 sccm of hydrogen gas were flowed at about 600° C. for about 30 minutes. 100 sccm of hydrogen gas and 400 sccm of ethene (C ₂ H ₄ ) gas were flowed at about 600° C. for about 1 hour, and then cooled to room temperature while flowing 500 sccm of nitrogen gas.

Example (weight ratio) One 2 3 4 5 6 7 Alkyl amines having 6 carbon atoms One - One One One One One Alkyl amines having 18 carbon atoms - One 3 5 7 10 12 * Alkyl amine having 6 carbon atoms: Hexylamine
* C18 alkyl amine: Octadecylamine

In Table 1, Example 1 uses only an alkyl amine having 6 carbon atoms, and Example 2 uses only an alkyl amine having 18 carbon atoms.

Unit: parts by weight Examples 1 to 7 Ethylene propylene diene monomer 100 Carbon nanofiber structure 3 Carbon black 70 Calcium carbonate 30 Zinc oxide 5 Stearic acid One Process oil 40 sulfur 0.7 Zinc dibutyl dithiocarbamate (ZnBDC) One Tetramethylthiuram disulfide 0.6 Mercaptobenzothiazole 0.6 * Vulcanization conditions: 170 ℃, 10 minutes

Example 8

It was prepared in the same manner as in Example 5, except that 1 part by weight of 1H,1H,2H,2H-perfluorodecanethiol was further included based on 100 parts by weight of the ethylene propylene diene monomer.

Example 9

It was prepared in the same manner as in Example 3, except that 1 part by weight of the carbon nanofiber structuring agent was mixed with respect to 100 parts by weight of the ethylene propylene diene monomer.

Example 10

It was prepared in the same manner as in Example 3, except that 5 parts by weight of the carbon nanofiber structuring agent was mixed with respect to 100 parts by weight of the ethylene propylene diene monomer.

[Comparative Example]

Comparative Example 1

Except in the same manner as in Example 3, except that a separate acid treatment, alkyl amine treatment was not used, except that carbon nanofibers were used.

Comparative Example 2

It was prepared in the same manner as in Example 3, except that the acid treatment (1) was not performed.

Comparative Example 3

It was prepared in the same manner as in Example 3, except that the alkyl amine treatment (2) was not performed.

Comparative Example 4

It was prepared in the same manner as in Example 3, except that the alkyl amine having 3 carbon atoms (propyl amine) was used.

Comparative Example 5

It was prepared in the same manner as in Example 3, except that the alkyl amine having 23 carbon atoms (Tricosylamine: Tricosylamine) was used.

Comparative Example 6

It was prepared in the same manner as in Example 3, except that 0.1 parts by weight of a carbon nanofiber structuring agent was mixed with respect to 100 parts by weight of an ethylene propylene diene monomer.

Comparative Example 7

It was prepared in the same manner as in Example 3, except that 10 parts by weight of a carbon nanofiber structuring agent was mixed with respect to 100 parts by weight of an ethylene propylene diene monomer.

Comparative Examples 8 to 11

It was prepared in the same manner as in Example 3, except that (1) acid treatment or (2) alkyl amine treatment was performed at a temperature of the following Table 3 [unit: ℃].

Comparative Example 8 Comparative Example 9 Comparative Example 10 Comparative Example 11 (1) Acid treatment temperature (℃) 70 90 80 80 (2) Alkyl amine treatment temperature (℃) 80 80 65 85

[In the experiment]

Experimental Example 1: XPS analysis

The carbon nanofiber of Comparative Example 1, the carbon nanofiber acid-treated according to (1) of Example 5, and the carbon nanofiber structure of Example 5 were subjected to XPS analysis [surface\Al 300W\Manual Point] according to the following conditions, It is shown in Figure 2.

At this time, the graph on the left in FIG. 2 refers to the carbon nanofibers of Comparative Example 1, the middle graph is the carbon nanofibers acid-treated according to (1) of Example 5, and the graph on the right is the carbon nanofibers of Example 5. It means a fiber structure.

-XPS analysis conditions

* Total acq. Time: 1 mins 50.1 secs

* No. Scans: 1

* Source Type: Al K Alpha

* Lens Mode: LAXPS

* Analyser Mode: CAE-Pass Energy 50.0 eV

* Energy Step Size: 1.000 eV

* No. of Energy Steps: 1101

Referring to FIG. 2, when the general carbon nanofibers are acid-treated, it can be seen that the peaks of oxygen, which mean a hydroxyl group and a carboxyl group, increase.

When the acid-treated carbon nanofibers are treated with an alkyl amine, the carbon peak increases due to the influence of the hydrocarbon chain of the alkyl amine, which means that the hydroxyl and carboxyl functional groups are substituted with the hydrocarbon chain. In addition, it can be seen that the nitrogen peak is seen by the amine group bonding.

Experimental Example 2: Evaluation of dispersibility and dispersion stability

(1) Visual evaluation of dispersibility and dispersion stability

1 g of the carbon nanofiber structure prepared according to the Examples and Comparative Examples and 100 g of PAO Oil were mixed, and then subjected to ultrasonic treatment [80°C, about 1 hour] to prepare a dispersion of the carbon nanofiber structure. At this time, in the case of Comparative Example 1, a dispersion was prepared using carbon nanofibers, and in the case of Example 8, a dispersion was prepared by adding 0.3 g of 1H, 1H, 2H, 2H-perfluorodecanethiol.

On the other hand, in the case of Examples 9 and 10 and Comparative Examples 6 and 7 using the same carbon nanofiber structure as in Example 3, separate experiments were not conducted.

After preparing the dispersions of the above examples and comparative examples, the appearance immediately after preparation, after 20 days, after 25 days, after 30 days, after 35 days and after 40 days was visually evaluated to evaluate dispersibility and dispersion stability. Dispersibility and dispersion stability were indicated by Ⅹ and ○, and the results are shown in Table 4 below.

Ⅹ: No aggregation, precipitation, or delamination occurs

○: Aggregation, precipitation, and delamination occur

Immediately after manufacture After 20 days 25 days later 30 days later After 35 days 40 days later Example 1 Ⅹ Ⅹ ○ ○ ○ ○ Example 2 Ⅹ Ⅹ ○ ○ ○ ○ Example 3 Ⅹ Ⅹ Ⅹ ○ ○ ○ Example 4 Ⅹ Ⅹ Ⅹ Ⅹ ○ ○ Example 5 Ⅹ Ⅹ Ⅹ Ⅹ Ⅹ ○ Example 6 Ⅹ Ⅹ Ⅹ Ⅹ ○ ○ Example 7 Ⅹ Ⅹ Ⅹ ○ ○ ○ Example 8 Ⅹ Ⅹ Ⅹ Ⅹ Ⅹ Ⅹ Comparative Example 1 Ⅹ ○ ○ ○ ○ ○ Comparative Example 2 Ⅹ ○ ○ ○ ○ ○ Comparative Example 3 Ⅹ ○ ○ ○ ○ ○ Comparative Example 4 Ⅹ ○ ○ ○ ○ ○ Comparative Example 5 Ⅹ ○ ○ ○ ○ ○ Comparative Example 8 Ⅹ ○ ○ ○ ○ ○ Comparative Example 9 Ⅹ ○ ○ ○ ○ ○ Comparative Example 10 Ⅹ ○ ○ ○ ○ ○ Comparative Example 11 Ⅹ ○ ○ ○ ○ ○

Looking at Table 4, it can be seen that in the case of this Example, dispersibility and dispersion stability are improved compared to Comparative Example.

According to the present embodiment, it can be seen that when a C5-C10 alkyl amine and a C15-C20 alkyl amine are included in a specific ratio, dispersibility and dispersion stability are improved. In particular, it can be seen that dispersibility and dispersion stability are improved when 1H,1H,2H,2H-perfluorodecanethiol is further included.

(2) Photograph of Example 5 and Comparative Example 1

3 and 4 illustrate the preparation of the dispersion containing the carbon nanofiber structure of Example 5 and the dispersion containing the carbon nanofiber of Comparative Example 1 immediately after and after 20 days.

In Figs. 3 and 4, the vial bottle labeled CNF is a dispersion using Comparative Example 1 (carbon nanofiber), and the vial bottle labeled ODA-CNF is a dispersion using Example 5 (carbon nanofiber structure).

Referring to FIG. 3, it can be seen that immediately after manufacture, when the carbon nanofiber structure is included and when the carbon nanofiber is included, both are uniformly dispersed and phenomena such as aggregation and layer separation do not occur.

Referring to FIG. 4, it can be seen that, in the case of the dispersion liquid using Example 5, when 20 days have passed since preparation, phenomena such as layer separation and aggregation do not occur. On the other hand, in the case of the dispersion using Comparative Example 1, it can be seen that phenomena such as layer separation and precipitation occur.

That is, according to Experimental Example 2, it can be confirmed that the carbon nanofiber structure of the present example has excellent dispersibility and long-term dispersion stability.

Experimental Example 3: Evaluation of physical properties (elongation/tensile strength/permanent compression reduction rate)

Elongation, tensile strength, and permanent compression reduction ratio of the rubber composites prepared according to Examples and Comparative Examples were measured, and are shown in Table 5 below. Each item was measured according to the following test standards.

-Elongation (%): KS M 6518

-Tensile strength (kgf/cm ² ): KS M 6518

-Permanent compression reduction rate (%): KS M 6518[Temperature 70 ± 1 ℃, 22 hours]

Elongation The tensile strength Permanent compression reduction rate Example 1 375 95 31 Example 2 381 96 32 Example 3 430 119 25 Example 4 475 136 22 Example 5 490 145 18 Example 6 476 138 21 Example 7 425 118 27 Example 8 510 153 15 Example 9 403 115 30 Example 10 435 120 27 Comparative Example 1 276 68 50 Comparative Example 2 304 80 47 Comparative Example 3 289 75 48 Comparative Example 4 342 82 40 Comparative Example 5 336 81 42 Comparative Example 6 241 54 55 Comparative Example 7 387 101 35 Comparative Example 8 310 72 45 Comparative Example 9 319 76 42 Comparative Example 10 314 72 44 Comparative Example 11 321 79 43

Referring to Table 5, it can be seen that in Examples 1 to 10 according to the present embodiment, the elongation, tensile strength, and permanent compression reduction rate are excellent. On the other hand, in the case of Comparative Examples 1 to 11, which do not follow the present embodiment, it can be seen that the elongation, tensile strength, and permanent compression reduction rate are significantly lower than in the Example.

Experimental Example 4: Heat resistance evaluation (elongation/tensile strength)

The heat resistance (aging resistance) of the rubber composites according to Examples and Comparative Examples was evaluated, and the results are shown in Table 6 below.

After measuring the tensile strength and elongation of the rubber composites according to the examples and comparative examples, the tensile strength and elongation of the rubber composites according to the examples and comparative examples were measured at about 70 ± 1 °C for about 70 hours, Table 6 shows the degree of change. The tensile strength and elongation were measured in the same manner as in Experimental Example 3.

In addition, in Table 5,-indicates when tensile strength and elongation are decreased, and + indicates when tensile strength and elongation are increased.

The tensile strength
Rate of change (%) Elongation
Rate of change (%) The tensile strength
Rate of change (%) Elongation
Rate of change (%) Example 1 -29 -37 Comparative Example 1 -46 -84 Example 2 -28 -33 Comparative Example 2 -40 -77 Example 3 -18 -30 Comparative Example 3 -40 -80 Example 4 -14 -24 Comparative Example 4 -32 -57 Example 5 -12 -20 Comparative Example 5 -33 -58 Example 6 -14 -23 Comparative Example 6 -48 -88 Example 7 -18 -31 Comparative Example 7 -30 -55 Example 8 -10 -15 Comparative Example 8 -38 -63 Example 9 -28 -35 Comparative Example 9 -36 -61 Example 10 -16 -28 Comparative Example 10 -37 -63 Comparative Example 11 -35 -59

Looking at Table 6, it can be seen that when heat treatment is performed, the tensile strength and elongation of the rubber composite are overall reduced (-).

In the case of Examples 1 to 10 according to the present embodiment, it can be seen that the tensile strength is reduced by up to 29%. On the other hand, in the case of Comparative Examples 1 to 11, it can be seen that the tensile strength was reduced by a minimum of 30% and a maximum of 48%.

In addition, in the case of Examples 1 to 10 according to the present embodiment, it can be seen that the elongation is reduced by up to 37%. On the other hand, in the case of Comparative Examples 1 to 11, it can be seen that the elongation is reduced by a minimum of 55% and a maximum of 88%.

That is, the example according to the present example has less change in tensile strength and elongation due to heat treatment compared to the comparative example, which means that it has excellent heat resistance.

According to Experimental Examples 1 to 4, the dispersibility and long-term dispersion stability of the carbon nanofiber structure according to the present example are superior to that of general carbon nanofibers, thereby elongation, tensile strength, aging resistance, and permanent compression reduction rate of the rubber composite. It can be seen that the characteristics of are improved.

As described above, the description of the present invention is for illustrative purposes only, and those of ordinary skill in the art to which the present invention pertains can easily be modified into other specific forms without changing the technical spirit or essential features of the present invention. You can understand. Therefore, the embodiments described above are illustrative in all respects and should be understood as non-limiting. For example, each component described as a single type may be implemented in a distributed manner, and similarly, components described as being distributed may also be implemented in a combined form.

The scope of the present invention is indicated by the claims to be described later rather than the detailed description, and all changes or modified forms derived from the meaning and scope of the claims and their equivalent concepts should be interpreted as being included in the scope of the present invention. do.

Claims (11)

Including an ethylene propylene diene monomer (EPDM) and a carbon nanofiber structure,
The carbon nanofiber structure is a carbon nanofiber modified with an acid and an alkyl amine,
The alkyl amine is a rubber composite comprising carbon nanofibers having improved dispersibility, characterized in that it comprises an alkyl amine having 5 to 10 carbon atoms and an alkyl amine having 15 to 20 carbon atoms in a weight ratio of 1:5 to 10.
delete The method of claim 1,
The acid is a rubber composite comprising carbon nanofibers having improved dispersibility, characterized in that it contains at least one selected from the group consisting of nitric acid and sulfuric acid.
The method of claim 1,
The carbon nanofiber structure is a rubber composite comprising carbon nanofibers with improved dispersibility, characterized in that the carbon nanofibers are modified with an acid and an alkyl amine to form a peptide bond on the surface.
The method of claim 1,
The rubber composite is
A rubber composite comprising carbon nanofibers having improved dispersibility, comprising 0.5 to 7 parts by weight of the carbon nanofiber structure based on 100 parts by weight of the ethylene propylene diene monomer.
The method of claim 1,
The rubber composite is
1H,1H,2H,2H-perfluorodecanethiol (1H,1H,2H,2H-perfluorodecanethiol), characterized in that it further comprises, a rubber composite comprising carbon nanofibers with improved dispersibility.
The method of claim 6,
The rubber composite is
Characterized in that it comprises 0.5 to 7 parts by weight of the carbon nanofiber structure and 0.1 to 3 parts by weight of 1H,1H,2H,2H-perfluorodecanethiol based on 100 parts by weight of the ethylene propylene diene monomer, improved dispersibility Rubber composite containing carbon nanofibers.
In the manufacturing method of the rubber composite of claim 1,
A first step of acid-treated carbon nanofibers to form acid-treated carbon nanofibers;
A second step of forming a carbon nanofiber structure by treating the acid-treated carbon nanofibers with an alkyl amine; And
Including a third step of mixing the carbon nanofiber structure and ethylene propylene diene monomer (EPDM),
The carbon nanofiber structure is a carbon nanofiber modified with an acid and an alkyl amine,
The alkyl amine is a method for producing a rubber composite including carbon nanofibers with improved dispersibility, characterized in that it contains an alkyl amine having 5 to 10 carbon atoms and an alkyl amine having 15 to 20 carbon atoms in a weight ratio of 1: 5 to 10 .
The method of claim 8,
The first step is characterized in that carried out at 75 ~ 85 ℃, the method for producing a rubber composite containing carbon nanofibers with improved dispersibility.
The method of claim 8,
The second step is characterized in that carried out at 70 ~ 80 ℃, the method for producing a rubber composite containing carbon nanofibers with improved dispersibility.
The method of claim 8,
In the third step
1H,1H,2H,2H-perfluorodecanethiol (1H,1H,2H,2H-perfluorodecanethiol), characterized in that further mixing, dispersibility improved method for producing a rubber composite containing carbon nanofibers.

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