KR101745623B1 - Incombustible film coating material containing expanded graphite and the manufacturing and using method of the same - Google Patents

Abstract

The present invention relates to a nonflammable coating film coating agent to which expanded graphite is added by heating expanded graphite, and more particularly, to an expandable graphite coating composition containing expandable graphite by heating expanded graphite at a temperature of 200 ° C. to 1,000 ° C. The expanded graphite is produced by expanding the various organic materials and enlarging the volume about 500 times to produce a flame barrier layer. The coated graphite can be added to a coating agent to produce a coating material having nonflammability.
According to the present invention, when the coating material is manufactured using expanded graphite, it is expected that there is no risk of injury due to harmful substances such as sulfuric acid or carbon dioxide which is generated during expansion upon heating.

Description

FIELD OF THE INVENTION [0001] The present invention relates to a non-flammable coating film coating composition containing expanded graphite,

The present invention relates to a nonflammable coating film coating agent to which expanded graphite is added by heating expanded graphite, and more particularly, to an expandable graphite coating composition containing expandable graphite by heating expanded graphite at a temperature of 200 ° C. to 1,000 ° C. The expanded graphite is produced by expanding the various organic materials and enlarging the volume about 500 times to produce a flame barrier layer. The coated graphite can be added to a coating agent to produce a coating material having nonflammability. The expanded graphite is expanded by heating, and the flame shielding layer generated by the expansion maintains its structure in spite of grinding, so that the non-burning performance is maintained.

Graphite is one of the crystalline forms of carbon, which is in the form of a plane hexagonal shape, and in which the sheet form in which the carbon atoms are bonded forms a laminate. Carbon-carbon bonds between hexagonal planes are strong bonds like diamond, but lamination of sheets is weak bond, so it is easy to peel. Here, it is a well-known technique to produce graphite intercalation compounds in such a manner that ions or molecules are inserted between sheets.

Double expanded graphite is produced as an interlayer intercalation compound. When a graphite intercalation compound in which a substance is inserted between sheets using a chemical reaction is rapidly heated, substances present in the interlayer may be burned and gasified, and the gas The graphite expands in the direction perpendicular to the lamination of the layers. In some cases, it may expand to several hundreds times the size of graphite. By using such expanded graphite, a graphite sheet rich in flexibility can be produced for industrial use. Expansive graphite has the same crystal structure as graphite, but expanded graphite exhibits a lower crystallinity than graphite because it is in an expanded state between layers.

When the expanded graphite is expanded by heating, it forms a kind of film. Therefore, when the expanded graphite is mixed with styrofoam, urethane or the like, the expanded material acts as a protective film when the above materials are heated. Styrofoam and urethane are the flame retardant materials. In addition, expanded graphite may be used in coatings such as paints.

Korean Patent No. 0996720 discloses a composition for forming a nonflammable coating film and a nonflammable coating film obtained therefrom. In the above prior art, 50.4 to 64.8% by weight of at least one binder resin selected from a water-soluble or water-dispersible acrylic resin and a water-soluble or water-dispersible vinyl-based resin; (b) 19.6-25.2 wt% water; (c) 6 to 26% by weight of expandable graphite; And (d) 2 to 4% by weight of black soybean oil, and a nonflammable coating film obtained from the composition. According to this, not only the drying speed and the long-term storage property are excellent, but also when the composition is used, a dense resin-expanded graphite nonflammable coating film is easily formed on the surface of the substrate to form a nonflammable coating film having excellent water resistance, heat resistance and mechanical strength . The expandable graphite expands upon exposure to a high temperature of 200 ° C or higher, and a flame-retardant layer is formed.

However, the solid powder of expanded graphite is not less than 400mesh (35 탆) even if the size of the granules is minimized by grinding it. When this is added to the coating agent, the texture of the granules is distinguished from the coating agent of the fluid, And thus it is not easy to apply it directly to a coated body requiring a smooth surface. In particular, in the case of paints, since the soft color and texture of the paint must be maintained, there is a problem that it is difficult to secure such original color and texture when the conventional expanded graphite is added.

In the case of using expanded graphite according to the prior art, when expanded graphite added to a coating agent is used in addition to the coating agent, the expanded graphite expands and destroys the outer surface of the coated material, and toxic substances such as sulfuric acid and carbon dioxide are generated (Binder) to be used as a coating agent and a problem that it can not be used in a region where there is always a high temperature rather than a case of a fire accident or the like, a problem that the rust-preventive function is low, It is contrived to solve the problem that the texture and aesthetics of the coated body are different or unfavorable from those expected when the coating agent is added to the coating agent and that the smoke-proofing function is relatively weak.

Accordingly, it is an object of the present invention to provide a coating material which is obtained by mixing expanded graphite, which is softened and easily pulverized by heating expanded graphite, into a coating agent and pulverizing the same into finer particles than existing expanded graphite particles, The purpose of the present invention is to greatly alleviate the texture and maintain the original texture of the coating agent as much as possible.

In particular, the present invention utilizes expanded graphite produced by expanding graphite by several hundreds of times by heating expanded graphite, and the expanded graphite is nonflammable as a flame blocking layer, and the horizontal thermal diffusion function is about 20 to 30 It is possible to maintain a stronger incombustibility.

Another object of the present invention is to prevent the generation of harmful substances while maintaining the flame-retarding function upon heating the coated body by expanding the expanded graphite to remove the harmful substances.

When normal graphite is heated to the same heating temperature (200 to 1000 ° C) as in the present invention, the firing temperature is very high, so that sufficiently expanded graphite as in the present invention can not be produced. The expanded graphite according to the present invention can be produced, and it is characterized by the fact that expanded graphite is prepared starting from expanded graphite.

It is another object of the present invention to provide an anticorrosive function of a coating agent containing expanded graphite which is excellent in acid resistance to almost all chemical components except for a strong acid agent.

It is another object of the present invention to provide a non-combustible coating agent by applying already expanded graphite so that the surface of the coated object is not deformed even when the coated body is heated do.

Another object of the present invention is to develop a coating material having a rust-inhibiting function with a reduced coating ratio by not using a primer coating agent because the rust-inhibiting function of expanded graphite is excellent.

It is another object of the present invention to develop a coating product having good adhesion by utilizing the adsorption force of expanded graphite.

That is, since expanded graphite does not have excellent adsorption power such as expanded graphite, it must be used in combination with a binder having a different adsorptive power to function as a coating agent, and expanded graphite can be added singly to a coating agent because of its strong adsorption ability.

In order to achieve the above-described object, the present invention provides a method for producing a graphite powder, comprising: a pulverized powder or powder of expanded graphite, The present invention also provides a nonflammable coating film coating agent to which expanded graphite is added.

The particle size of the expanded graphite is preferably in the range of 0.1 to 20 mu m.

When the volume of the coating agent is 100% when the coating agent is mixed with the coating agent, the amount of the expanded graphite is preferably in the range of 50 to 100% by volume relative to the coating agent.

The present invention also provides a method for producing expanded graphite by heating expanded graphite and using the expanded graphite as an additive for a coating agent.

According to the present invention, when an incombustible coating film is produced using expanded graphite, it is anticipated that the harmful substances such as sulfuric acid and carbon dioxide, which are generated during expansion during heating, will not cause personal injury.

In addition, the present invention is expected to have an effect of enabling the production of a coating agent and coating on a coating material without using a binder by using expanded graphite excellent in bonding performance as compared with expanded graphite.

Further, the present invention is expected to have an action effect of preventing the surface of the coated body from being damaged or changed even when the coated body to which the coating agent is applied is used at a temperature higher than 200 캜.

In addition, since the present invention is in a state of fine particles in the coating agent as compared with that of expanded graphite, expanded graphite is dispersed in a larger amount than expandable graphite in a coating agent, and therefore, . That is, the expanded graphite and the expanded graphite have the same level of flame shielding function per se, but the expanded graphite can be crushed more finely so that the surface area capable of flame retarding function is wider.

Further, the present invention is expected to have an action effect of enhancing the rust-preventing function of the coating agent to which the expanded graphite is applied by using the expanded graphite with high acid resistance.

In addition, since the present invention uses already-expanded graphite, further deformation is not caused even by high heat, and therefore, it is expected that a coating agent to which the expanded graphite is applied can be used in more products that are likely to come into contact with heat.

The present invention also provides a coating composition containing expanded graphite, which is expanded and pulverized after adding graphite separated from the coating layer to the coating agent to produce a coating agent containing the expanded graphite, An action effect that can be obtained is expected.

1 is an electron micrograph showing the structure of a conventional expanded graphite and an electron micrograph showing a structure of the expanded graphite of the present invention.
Fig. 2 is a comparative example of the case where the expanded graphite of the present invention is applied to a coating agent and the case where expanded graphite is applied to a coating agent.
Fig. 3 is a comparative example of the case where the expanded graphite of the present invention is applied to a coating agent and the case where expanded graphite is applied to a coating agent.
4 is a test report showing the result of applying the expanded graphite of the present invention to a coating agent and performing adhesion test on the same.
5 is a test report showing the result of applying the expanded graphite of the present invention to a coating agent and performing a rust-preventive function test on the coated graphite.

Hereinafter, the present invention will be described in more detail based on the accompanying drawings and preferred embodiments.

The coating agent referred to in the present invention refers to a liquid phase applied to protect the outer surface of a coating material or to make its appearance clear, or a solid material that can be heated or chemically dissolved, and includes a paint or the like.

The expanded graphite used in the present invention is produced by artificially expanding expanded graphite by heating the expanded graphite. The graphite is similar in physical properties to expanded graphite. However, it is advantageous in terms of application especially when it is used as a coating agent, The present invention has been recognized as being equivalent or superior to expanded graphite. That is, expanded graphite is an expandable graphite, and expanded graphite produced by heating it again has properties such as incombustibility, flexibility, porosity, strong binding force, adsorption force, etc. It is also expressed in expanded graphite, Since it has never been applied to coatings such as paints so as to have a fire-retardant performance after being expanded and pulverized, it is a feature of the present invention.

The expanded graphite is changed into a large volume material having a strong adsorption force so that it can be mixed with the coating agent when mixed with the coating agent and fine particles can be realized more than the expanded graphite by the fine pulverization, so that the amount of graphite present in the unit volume in the coating agent And thus the surface area occupied by graphite is higher than that of expanded graphite, so that the horizontal thermal diffusing function can be enhanced by a factor of several tens of times.

When such a coating agent is applied to a coating body, a strong cohesive force can be formed when the coating agent is solidified, so that a positive effect can be obtained in terms of incombustibility. Due to this excellent horizontal thermal diffusing function, graphite after swelling has more favorable conditions than thermal expansion graphite for heat insulation coatings, heat transfer coatings, and fireproof coatings.

In addition, the strong adsorption of expanded graphite makes it possible to produce a coating with good adhesion. The excellent oxidation resistance is not oxidized at 450 ° C. or lower, and it can be manufactured as a coating having excellent rust resistance because it is resistant to almost all chemical mediators have.

In addition, since expanded graphite is expanded to a high temperature of 200 ° C or more, a flame barrier layer is formed. Therefore, the use of a coating material having expanded graphite added to a product or area where heat of 200 ° C or more is generated, such as in automobile muffler, butane gas cover, Since the expanded graphite can be used irrespective of the generation of heat, the application area of the coating material containing the expanded graphite is wider.

Expansion graphite and expanded graphite have similarities in that they have heat resistance, cold resistance, anticorrosive property, self-lubrication, and strong radiation resistance, but expanded graphite and expanded graphite exhibit somewhat different performance characteristics as shown in Table 1 below .

Expanded graphite Expanded graphite ingredient Atomic weight standard
C:> 70
O: 15
N, S, Na: < 5
HSO ₄ ^-
SO ₄ ^2- Atomic weight standard
C:> 90
O: <8
N, S, Na: < 1
CC:> 70 CO: 10-20
C = O: < 10 OC = O: < 8 Performance - Pressure resistance, flexibility, plasticity.
Excellent vibration resistance performance

- Prevention of weathering

- As a flame retardant in fire-retardant paints, it has anti-static, flame retardant, moisture-proof, reduced smoke emission and excellent synergy.

- Large particle size, difficult to crush pores, difficult to mix with coating agent

- Expansive graphite has a limit of pulverization,
When used in coatings, particles are large
Coarse appearance occurs when coating agent is applied - Physical properties of graphite such as high temperature, low temperature, corrosion, conductivity, heat conduction

- Has flexibility, porosity and strong adsorption

- It is more porous than expandable graphite and it has a bigger gap structure, so it is easy to adsorb large molecular substances, especially nonpolar to molecular, and fine-grained with other materials. The expanded graphite is less dense due to the fact that the interlayer material is removed compared to expanded graphite and the interlayer structure is expanded by expansion

The thermal conductivity (thermal diffusivity) in the plane direction is about 28 times larger than that of expanded graphite.

- It is non-oxidizing at temperatures below 450 ° C, which can withstand almost all chemical intermediates except some powerful oxidizing agents such as aqua regia. That is, it is not necessary to separately perform anti-rust treatment because of its strong corrosion resistance
- Long term irradiation of various radiation does not cause decomposition, deformation and aging.

- Surface free energy by surfactant is rapidly increased and can be made into various products without binder (binder) with high adhesive force

- Crushing can double the advantages of graphite such as nonflammability and obtain desired properties. Similarity Heat resistance and cold resistance, corrosion prevention, self-lubrication, strong radiation resistance

The expanded graphite becomes expanded graphite by heating, and the carbon atoms in the graphite and the additive substances involved in the expansion participate in the redox reaction to produce sulfur dioxide, carbon dioxide, water, and then evaporate. This is expressed by the following formula (1).

C + 2H ₂ SO ₄ ? CO ₂ + 2H ₂ O + ₂ SO ₂ (1)

That is, when the expanded graphite is heated, toxic substances such as sulfur dioxide, carbon dioxide and the like are produced. Therefore, when the expanded graphite is converted into expanded graphite, the expanded graphite is already in a state where the toxic substance is removed, so that the toxic substance is not produced even when the expanded graphite is heated again. That is, the coating material to which the graphite expanded according to the present invention is applied has a characteristic that it does not produce a toxic substance while maintaining the refractory and flame-retarding function.

Normally, the temperature range required for expanding and expanding expanded graphite is 200 to 1000 ° C. In the present invention, expanded graphite is heated to a temperature selected within the above-mentioned temperature range to mix the expanded graphite with a coating agent to prepare a non-combustible coating agent.

If heated beyond the lower limit of the above temperature, the rate of conversion of the expanded graphite to expanded graphite becomes very low. If the graphite is heated beyond the upper limit of the above temperature, the unnecessarily high temperature is used for producing the expanded graphite However, since there is a problem that the expansion rate is reduced due to the collapse of the layered structure of the expanded graphite, which is excessively cracked between the layer and the layer, the above temperature range has a critical significance at the upper and lower limits.

On the other hand, the expanded graphite has a particle size in the range of 0.1 to 20 占 퐉 in the coating agent. If the particle size is below the lower limit, it takes a lot of energy to differentiate the particle size. If the upper limit is exceeded, the specific surface area indicated by the graphite after the expansion becomes small, which has an adverse effect on the fire retardant performance. Therefore, the particle size of the stoichiometric expanded graphite has its critical significance in the upper range.

Structural differences between the expanded graphite and the expanded graphite are as shown in FIG. In other words, expanded graphite has many layered structures, but the expanded graphite which is heated thereon is clearly divided between the layers, and a plurality of flower buds are formed. The layers are not completely separated from each other, It is like a pest. At the same time, there are a lot of small gaps in the niobium, which makes it possible to form an abundant gap structure with expanded graphite. Due to such a large clearance structure, the adsorbing force and bonding force to the coating agent are better than those of expanded graphite. In addition, since a large amount of the clearance structure is already formed, it can be easily pulverized when pulverized, and thus it is possible to realize a fine particle compared with expanded graphite. Therefore, when the same volume as the expanded graphite is added to the coating material, Graphite is much higher, and thus it is possible to realize abundant surface energy and horizontal thermal diffusing function.

Expanded graphite is instantly expanded at 900 ° C or higher and is fully expanded. After full expansion, it has ductility, plasticity and plasticity, which is usually close to that of graphite. However, due to these properties, expanded graphite reacts with carbon dioxide and oxygen in the air to function as a thermal diffusion in the plane direction in case of fire. But differs in that the non-combustible function can be added in terms of thermal diffusion in the planar direction.

FIG. 2 is a comparative example when the expanded graphite according to the present invention is applied to a coating agent and when expanded graphite is applied to a coating agent, which is a comparative example of the state before the heating, and FIG. 3 is a graph showing the expansion graphite As a comparative example in which the graphite is applied to a coating agent and the expanded graphite is applied to a coating agent.

As shown in FIG. 2, when the coating material to which the expanded graphite is added is applied to the coating material, expanded graphite grains are observed in the coating material matrix and the coarse texture is exhibited. However, in the nonflammable coating material It can be seen that the surface texture is smooth when the coating agent is applied to the coating material.

Also, as shown in FIG. 3, when the coating material to which the expanded graphite is added is applied to the coating material and heated, the expanded graphite swells up even though it is heated for only 30 seconds, and the coating material exhibits a rougher surface than before heating The coating layer is completely cracked and peeled off. However, when the non-flammable coating film containing the expanded graphite according to the present invention is applied to the coating material and heated, the surface is still smooth despite being heated for 3 minutes or more .

<Production Example>

The process for producing the coating agent of the present invention is as follows.

(a) First, expanded graphite is heated and expanded to produce expanded graphite. Or expanded expanded graphite may be used.

(b), the expanded graphite is immersed in the coating agent.

(c) then pulverized expanded graphite soaked in the coating. Here, if the coating agent is a solid phase, it is preferable to immerse the expanded graphite after making it into a liquid phase. This is because it is possible to easily pulverize expanded graphite by a method such as stirring or the like.

On the other hand, although the expanded graphite can be first pulverized and then mixed with the coating agent, the expanded graphite produced by heating the expanded graphite once is changed to a very weak state in terms of strength in terms of the strength in terms of the expanded graphite, Such an expanded graphite firstly pulverizes it, and it causes not only a large number of non-produced materials but also a quantitative loss of the expanded graphite. Therefore, it is preferable to mix the graphite powder with the coating material in the form of a powder or a pulverized product, , It is relatively difficult to mix the coating agent with the coating agent, and therefore, it can not be the best embodiment.

In short, according to the present invention, it is most preferable to mix expanded graphite with a coating agent before heating after pulverization and then pulverize the expanded graphite. Even in this way, since expanded graphite is very weak in its strength, it can be easily pulverized and mixed by physical stress such as stirring in a coating agent.

Here, when the volume of the expanded graphite is expressed as the relative volume by taking the volume of the coating agent as 100%, it becomes 50 to 100%. If the amount of the expanded graphite is less than 50 vol%, various functions due to the expanded graphite such as the fire retardant performance and the anti-corrosive function can not be sufficiently exhibited. If it exceeds 100 vol%, the viscosity becomes high, .

&Lt; Evaluation example &

The fire retardant performance, rustproofing ability, and adsorption force (binding force) of the expanded graphite and the expanded graphite are compared as follows.

Name Expanded graphite Expanded graphite Flammable performance Flame-shielding layer is formed by expanding by applying heat, and it has fire-retardant performance. The flame shielding layer which has the nonflammable performance makes the absorption of the coating material into the atomized state to have the nonflammable function, thereby exhibiting the broader fire retardant performance Anti-rust function The material obtained by heat treatment produces a material with excellent compressibility, elasticity and corrosion resistance. Adsorption power
(cohesion) The material obtained by the heat treatment is porous and is a particularly good absorbent for materials with large molecular sizes and weak polarity and is also studied as an oil adsorbent.

4 is a test report showing the result of applying the expanded graphite of the present invention to a coating agent and performing adhesion test on the same.

As can be seen, the expanded graphite according to the present invention was applied to the coating agent and applied to the coated body to show the highest adhesion, 5B. Therefore, it can be seen that the adhesion force, which is a physical property required as a coating agent, fully manifests the commercialization level.

5 is a test report showing the result of applying the expanded graphite of the present invention to a coating agent and performing a rust-preventive function test on the coated graphite.

As shown in the figure, the rheological performance of the expanded graphite according to the present invention applied to a coating agent and applied to a coated body showed no change in spite of a 100-hour salt spray test, Since no deterioration of performance of the coating agent was observed, it can be seen that this is also a level of no problem in commercialization.

As described above, when the expanded graphite is compared with the expanded graphite, the flame-retardant performance is superior to the expanded graphite, and it is found that the graphite is commercialized in terms of rust-preventive function and adsorptive power.

It is expected that the expanded graphite having various functions can be combined with the coating agent in an optimal combination with a coating material having a fire-retardant performance, especially a coating paint, and thus can be considered to be highly industrially applicable.

Claims (5)

The expandable graphite produced by heating ordinary graphite in an expandable state is heated again to produce graphite expanded by heating, and the pulverized powder or powder is pulverized;
Coating agents;
To impart flame retardancy to the coating,
Characterized in that the pulverized material or powder of expanded graphite is dispersed in the coating material. The method according to claim 1,
Wherein the expanded graphite has a particle size in the range of 0.1 to 20 占 퐉. The method according to claim 1,
Wherein the volume of the expanded graphite relative to the coating is in the range of 50% to 100%, when the volume of the coating is 100%. The method according to claim 1,
Wherein the coating agent is a coating material. A method for producing expandable graphite by heating by heating again expandable graphite produced by heating ordinary graphite in an expandable state and using it as an additive for a nonflammable coating film coating agent.

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