KR102488846B1 - Coating composition for wire cable coating - Google Patents

Abstract

The present invention relates to a coating composition for covering wire cables. The coating composition comprises: 50 to 70 wt% of an aqueous ethylene vinyl acetate resin, 10 to 25 wt% of an expanded graphite-graphene composite, 5 to 15 wt% of titanium dioxide, 1 to 30 wt% of a thickener, 1 to 20 wt% of distilled water, and 1 to 5 wt% of silane-APP. The composition of the present invention is eco-friendly and economical because the composition does not contain halogens or heavy metals by adding an inorganic flame retardant instead of a phosphorus-based flame retardant. By adding silane-APP to improve adhesion and tensile strength, the composition has excellent flame retardancy, insulation, flexibility and durability, and thus is very suitable as a paint for covering wire cables.

Description

Coating composition for wire cable coating {Coating composition for wire cable coating}

The present invention relates to a paint composition that can be used as a wire cable covering material, and more specifically, 50 to 70% by weight of an aqueous ethylene vinyl acetate resin, 10 to 25% by weight of an expanded graphite-graphene composite, titanium dioxide (TiO ₂ ) 5 to 15% by weight, 1 to 30% by weight of a thickener, 1 to 20% by weight of distilled water, and 1 to 5% by weight of silane-APP.

Wire cables used in electrical and electronic components require various properties such as flame retardancy, physical properties after heat aging, low temperature properties, heat resistance, oil resistance, and weather resistance, and a high level of flame retardancy is required, especially in North American countries. In Korea, there are fire safety standards (NFSC 506) for combustion prevention facilities, and according to Article 7 (Coating of anti-combustion paint), anti-combustion paint that meets the standards of each subparagraph must be applied to cables and wires. It specifies that

However, despite the above safety standards, most of the existing combustion inhibitors meet only the minimum standards or are measured below the standards. On the other hand, there are materials that are economical while satisfying all of these requirements, but most of them are materials containing PVC or halogen flame retardants. In the case of PVC, toxic gases such as hydrogen chloride and dioxin that can threaten the human body and the natural environment are generated during fire or incineration after use. is being discussed. In addition, even in the case of other resins containing halogen flame retardants, there are many restrictions on their use because hydrogen halide, which is harmful to the human body and the natural environment, is generated.

Recently, as a coating material for an alternative non-halogen wire that can improve these problems, a composition based on a polyolefin resin and adding a metal hydroxide such as magnesium hydroxide or aluminum hydroxide has been proposed. However, in the case of such a composition, since an excessive amount of metal hydroxide must be added in order to express flame retardant performance, there is a disadvantage in that physical properties such as flexibility and elongation of the wire are lowered. Moreover, it is difficult to inject due to the phenomenon of sticking to each other between additives including powdered metal hydroxide and various powdery flame retardants.

As another method, a method of imparting flame retardancy by using polyphenylene oxide together with an elastomer and a phosphorus-based flame retardant has been proposed, but this is a system in which polyphenylene oxide forms a carbonized layer to form a solid barrier film to block heat and oxygen. Therefore, the flame retardant performance cannot be expressed with the elastomer alone. In particular, since the polyphenylene oxide is not a resin having flexible properties, increasing the content of polyphenylene oxide to achieve flame retardancy causes a problem in that various physical properties that a resin for covering wires should have, such as flexibility, are deteriorated.

In addition, essential requirements for the application of wire cables are to prevent fire risk and performance degradation due to degradation of cable performance and damage to sheath due to temperature rise of cable conductors. Therefore, it is necessary to secure stability and efficiency by preventing heat accumulation in the cable conductor and evenly distributing and distributing the heat to drastically lower the temperature.

Accordingly, the present inventors use an inorganic flame retardant instead of a phosphorus flame retardant as a paint for wire cable coating, and silane-APP to enhance adhesion and tensile strength and expanded graphite-graphene for heat dissipation in the cable conductor. In the case of adding a composite, it was found that excellent flame retardancy, heat insulation, flexibility, durability, eco-friendliness and stability can be secured, thereby completing the present invention.

Domestic Patent No. 10-2176985

An object of the present invention is to provide a paint composition suitable for covering electric wires and cables, which has excellent properties such as flame retardancy, heat insulation, flexibility, durability, etc. required for covering electric wires and cables.

Another object of the present invention is to provide an eco-friendly wire cable having excellent flame retardancy and heat insulation effect as well as water resistance, weather resistance and flexibility, and not containing halogen by applying the coating composition.

In order to achieve the above object, according to one embodiment of the present invention, an aqueous ethylene vinyl acetate copolymer (Ethylene vinyl acetate copolymer) 50 to 70% by weight; Expanded graphite-graphene composite 10 to 25% by weight; Titanium dioxide (TiO ₂ ) 5 to 15% by weight; Ammonium polyphosphate (APP) as a core material, 1 to 5% by weight of silane-APP coated with vinyltrimethoxysilane on its surface; 1 to 30% by weight of a thickener; and 1 to 20% by weight of distilled water.

In a preferred embodiment of the present invention, the expanded graphite-graphene composite comprises layered expanded graphite having a particle size of 50 to 200 mesh and graphene having a thickness of 0.1 to 0.5 nm in a weight ratio of 50:1 to 200:1. It is prepared by dispersing graphene in the air layer on the expanded graphite layer by putting it in a mixer and dispersing for 30 minutes. Here, the particle size of the expanded graphite is more preferably 80 mesh, and the thickness of the graphene is more preferably 0.3 nm.

In one embodiment of the present invention, the coating composition for wire cable coating of the present invention is titanium pyrophosphate (TiP ₂ O ₇ ) It further includes 1 to 5% by weight.

In one embodiment of the present invention, silane-APP is preferably included in 0.002 to 0.02 parts by weight of vinyltrimethoxysilane per 100 parts by weight of ammonium polyphosphate.

In one embodiment of the present invention, the expanded graphite-graphene composite and titanium dioxide used in the composition of the present invention are preferably included in a weight ratio of 1:1 to 2:1.

In one embodiment of the present invention, it is preferred that the thickener used in the composition of the present invention is silica.

In one embodiment of the present invention, the composition of the present invention may further include any one or more additives selected from the group consisting of a dispersing agent, an antifoaming agent, a plasticizer, a stabilizer, a fluidizing agent, and a preservative.

The coating composition for electric wire and cable coating according to the present invention is eco-friendly and economical because it does not contain halogens and heavy metals by adding inorganic flame retardants instead of phosphorus-based flame retardants, and silane-APP for enhancing adhesion and tensile strength and By adding an expanded graphite-graphene composite for heat dissipation, excellent flame retardancy, insulation, flexibility, durability, eco-friendliness and stability are ensured, making it useful for application to moving materials such as electric wires and cables.

1 is a schematic diagram showing the structure of silane-APP powder prepared in Preparation Example 1 of the present invention.
Figure 2 is a photograph showing the process of conducting a torch lamp direct heat test after applying the composition on a sheet in order to evaluate the flame retardancy and heat insulation properties of the paint composition prepared in one embodiment of the present invention.
Figure 3a is a photograph showing the process of conducting a torch lamp direct heat test after applying the composition to a cable in order to evaluate the flame retardancy and heat insulation properties of the paint composition prepared in Comparative Example 1.
Figure 3b is a photograph showing the process of conducting a torch lamp direct heat test after applying the composition to a cable in order to evaluate the flame retardancy and heat insulation properties of the paint composition prepared in Comparative Example 4.
Figure 3c is a photograph showing the process of conducting a torch lamp direct heat test after applying the composition to a cable in order to evaluate the flame retardancy and heat insulation properties of the paint composition prepared in Example 4.
Figure 4a is to prepare a test for measuring the temperature of the copper plate by painting a flame retardant paint on a rubber plate on a copper plate and making a hole in the center in order to evaluate the heat dissipation characteristics of the paint composition prepared in one embodiment and comparative example of the present invention. It is a picture.
Figure 4b is a photograph showing the process of measuring the temperature of the copper plate after coating the coating composition prepared in Example 2 of the present invention on the rubber plate on the copper plate and heating it.
Figure 4c is a photograph showing the process of measuring the temperature of the copper plate after painting the coating composition prepared in Comparative Example 6 of the present invention on the rubber plate on the copper plate and heating it.
Figure 4d is a photograph showing the process of measuring the temperature of the copper plate after painting the coating composition prepared in Comparative Example 8 of the present invention on the rubber plate on the copper plate and heating it.
5 is a result of testing the structure and appearance after applying the composition prepared according to an embodiment of the present invention to a cable.
6 shows a specimen having a width of 2.5 cm and a length of 5 cm by curing the composition prepared according to an embodiment of the present invention, and then using a tensile tester (UTM) to measure the specimen according to KS F 3211 This is the result of measuring the tensile strength.
7 shows a specimen having a width of 2.5 cm and a length of 5 cm by curing the composition prepared according to an embodiment of the present invention, and then measuring the adhesive strength of the specimen by the KS F 3211 measurement method using a peel tester. This is the result.
8 is a result of conducting a harmful substance test of a composition prepared according to an embodiment of the present invention.
Figure 9 is in order to evaluate the cable allowable current reduction rate characteristics of the composition prepared according to an embodiment of the present invention and a comparative example, after connecting a test article coated cable and an uncoated cable to conduct AC 60 Hz current , is the result of temperature comparison of the two cable conductors.

Hereinafter, the present invention will be described in more detail to aid understanding of the present invention. At this time, the terms or words used in this specification and claims should not be construed as being limited to ordinary or dictionary meanings, and the inventor appropriately defines the concept of terms in order to explain his/her invention in the best way. It should be interpreted as meaning and concept consistent with the technical idea of the present invention based on the principle that it can be done.

The present invention provides a novel paint composition, which has been studied and completed so that it can be used for wire and cable coatings, as it has elasticity and flexibility as well as enhanced flame retardancy.

To this end, in one embodiment of the present invention, 50 to 70% by weight of an aqueous ethylene vinyl acetate resin, 10 to 25% by weight of an expanded graphite-graphene composite, 5 to 15% by weight of titanium dioxide (TiO ₂ ), 1 to 30% by weight of a thickener A coating composition for covering wire and cable comprising 1 to 20% by weight of distilled water and 1 to 5% by weight of silane-APP is provided.

The paint composition of the present invention includes a resin having excellent flexibility and a certain degree of flame retardancy in order to satisfy the flexibility required for the application of wire cables. In addition, it is characterized in that it contains ethylene vinyl acetate copolymer (EVA), which has excellent adhesion to various insulating materials and flame retardant required parts, and thus has excellent workability as well as flame retardant and flame retardant performance. Preferably, it may be a more environmentally friendly water-based EVA resin because it is non-toxic. The EVA resin is preferably included in 50 to 70% by weight of the total composition. If the EVA resin is included in less than 50% by weight, the flexibility of the composition may be reduced, and if included in more than 70% by weight, mechanical properties such as strength and durability of the composition may be reduced.

The coating composition of the present invention, in order to overcome the limitations of conventional flame retardants, such as phosphorus-based flame retardants, metal hydrate-based flame retardants, halogen-based flame retardants, bromine-based flame retardants, and flame retardant aids, the flame retardants Instead, by including an inorganic flame retardant, it is characterized by securing excellent flame retardancy, flexibility, durability and eco-friendliness. The inorganic flame retardant can perform a role as a reinforcing agent as well as a flame retardant, and can improve flame retardancy, mechanical properties, and abrasion resistance of a composition including the inorganic flame retardant.

The inorganic flame retardant has a decomposition temperature of about 200° C. or higher. When the decomposition temperature of the inorganic flame retardant is within the above range, physical properties may not be impaired during melt mixing with the resin. Specifically, the inorganic flame retardant preferably has a decomposition temperature of about 200°C to about 900°C, more specifically about 250°C to about 350°C. Examples of the inorganic flame retardant include magnesium oxide, magnesium hydroxide, calcium hydroxide, hydromagnesite (Mg5(CO3)4(OH)2, hydromagnesite), calcium carbonate ), potassium titanate, magnesium silicate, and a combination thereof. However, conventional inorganic flame retardants are more environmentally friendly than phosphorus-based flame retardants or halogen-based flame retardants, but have low flame retardancy.

Meanwhile, the coating composition of the present invention includes an expanded graphite-graphene composite and titanium dioxide among the inorganic flame retardants, thereby obtaining a composition having flame retardancy, flexibility, heat dissipation and durability.

The expanded graphite-graphene composite has advantages such as being non-toxic, light, not containing halogen components, insoluble in water, and not generating toxic gas. In addition, the titanium dioxide is also eco-friendly because it does not contain a halogen component, and has the advantage of improving insulation performance by storing heat.

The coating composition of the present invention includes the expanded graphite-graphene composite and titanium dioxide, and by adjusting the content and mixing ratio thereof, the low flame retardancy problem of existing inorganic flame retardants can be improved, and the flexibility and durability of the composition can be improved. can improve

The paint composition of the present invention is characterized in that it includes an expanded graphite-graphene composite as an inorganic flame retardant to block fumes caused by fire. In the composite, the expanded graphite expands when exposed to heat of 200° C. or higher, so that the flame can be protected from being transmitted to the entire wire cable. On the other hand, graphene is a material in the form of pieces obtained from graphite, and as a material that can secure economic feasibility as well as excellent heat dissipation properties, it is considered as a material that can replace existing metal heat dissipation materials. In the present invention, by injecting and dispersing such graphene in the internal space layer of the expanded graphite, it is intended to prevent heat accumulation and release heat in the cable.

Specifically, the expanded graphite-graphene composite according to the present invention contains layered expanded graphite having a particle size of 50 to 200 mesh and graphene having a thickness of 0.1 to 0.5 nm in a weight ratio of 50:1 to 200:1 in a mixer. and dispersed for 30 minutes to obtain an expanded graphite-graphene composite in which graphene is dispersed in an expanded graphite layer.

The expanded graphite used the property of being able to inject atoms or molecules between layers due to the structural characteristics of layered graphite. At this time, the graphene is a GNP-UC product, and it is preferable to use a high-purity product with a carbon purity of 99% or more and excellent crystallinity, but is not limited thereto. Accordingly, when the prepared expanded graphite-graphene composite is well mixed and dispersed, there is no scattering of graphene or detachment of fine particles. More specifically, the particle size of the expanded graphite used in the preparation of the expanded graphite-graphene composite is more preferably 80 mesh, and the thickness of the graphene is more preferably 0.3 nm.

Meanwhile, the weight ratio of the expanded graphite and graphene is preferably 50:1 to 200:1. If the content of graphene is lower than the above range, the heat dissipation efficiency is reduced and the effect is insignificant, and if the content of graphene is higher than the above range, the electrical conductivity in the cable is excessively increased, causing an electric spark. . Therefore, by mixing the expanded graphite and graphene at a weight ratio of 50:1 to 200:1, it is possible to achieve a high heat dissipation effect that appropriately lowers the temperature in the cable and the resulting safety of the coating.

On the other hand, the expanded graphite-graphene composite is preferably included in 10 to 25% by weight based on the weight of the total composition. If the composite is included in less than 10% by weight, the flame propagation prevention effect may be reduced, and if included in more than 25% by weight, it may be mixed more than necessary and rather reduce the flexibility and adhesiveness of the composition.

The coating composition of the present invention is characterized by including titanium dioxide (TiO ₂ ) as an inorganic flame retardant to improve flame retardancy, flexibility and durability of the EVA resin. TiO ₂ significantly reduces damage to the coating by improving insulation and flame retardancy to block heat diffused in the direction of the coating. Here, titanium dioxide is preferably included in 5 to 15% by weight based on the weight of the total composition. If titanium dioxide is included in less than 5% by weight, combustion resistance may be lowered, and if included in more than 15% by weight, elongation, tear strength and flexibility may be reduced.

The coating composition of the present invention is characterized in that it contains silane-APP to improve the adhesive strength and tensile strength of the composition. Here, silane-APP means a powder prepared by using ammonium polyphosphate as a core material and coating the surface with vinyltrimethoxysilane.

The APP used as a raw material is a phosphorus-nitrogen flame retardant, and generates phosphoric acid and polyphosphoric acid by thermal decomposition. At this time, the produced phosphoric acid and polyphosphoric acid exhibit a flame retardant effect by forming a carbonized layer (char) through esterification and carbonization. Vinyltrimethoxysilane used as a coating material for the APP is a vinyl functional silane having a reactive methoxy group. It is mainly used as a crosslinking agent and adhesion promoter in paints, sealants and plastic compounds. The silane-APP prepared according to them is in the form of a powder, is non-toxic and odorless, does not dissolve in container solutions, and has a water solubility of 0.25 or less and has excellent waterproofing power.

The specific structure of this silane-APP is shown in FIG. As can be seen in FIG. 1, in this type of silane-APP, vinyltrimethoxysilane located on the outside is first dissolved by heat, and this component binds the organic and inorganic components in the composition, thereby forming the particles of the foamed protective film. They work together to improve tensile strength and adhesion. That is, the improved tensile strength and adhesive strength in contact with heat prevent scattering and detachment of the coating film applied with the paint, and as a result, contribute to greatly improving the flame retardancy and heat insulating properties of the paint.

In addition, the silane-APP has high expansion efficiency, improves the heat resistance and waterproofness of the composition, and also acts to improve the dispersibility, miscibility and precipitation prevention of the resin. Meanwhile, after the vinyltrimethoxysilane on the surface of the silane-APP is decomposed by heat, the APP existing inside the silane-APP remains and acts as a flame retardant.

In this case, the silane-APP may be prepared by blending 0.002 to 0.02 parts by weight of vinyltrimethoxysilane per 100 parts by weight of ammonium polyphosphate. If the vinyltrimethoxysilane is included in an amount of less than 0.002 parts by weight, the effect of improving adhesion and tensile strength is insignificant, and when a flame occurs, the effect of preventing scattering and detachment of the paint film is hardly shown, and 0.02 weight Mixing in excess of parts may rather deteriorate workability.

On the other hand, the coating composition of the present invention, in order to further improve the fire resistance of the composition, titanium pyrophosphate (TiP ₂ O ₇ ) It may further include 1 to 5% by weight. The TiP ₂ O ₇ is prepared by reacting TiO ₂ with silane-APP and phosphorus pentoxide (P ₂ O ₅ ), and serves to withstand flame erosion and protect the resulting foamed char layer. In addition, the dryness of the composition is improved to facilitate workability. Accordingly, TiP ₂ O ₇ is included in the composition of the present invention in an amount of 1 to 5% by weight to reduce smoke concentration, thereby improving fire resistance and affecting workability.

The coating composition of the present invention is characterized by including the expanded graphite-graphene composite and titanium dioxide in a weight ratio of 1:1 to 2:1. When the above ranges are satisfied, it is possible to secure flame retardancy, flexibility, and durability that are most suitable for coating wire cables.

The coating composition of the present invention is characterized in that it further comprises a thickener in order to impart viscosity to the resin. Examples of the thickener include polysaccharide-based thickeners such as xanthan, cellulose-based thickeners such as carboxymethylcellulose, acrylate thickeners, polyether-modified polyurethane thickeners, bentone-based thickeners such as bentonite, titanate, and zirconate. It may be a metal organyl-based thickener, an organic clay-based thickener, silica, wax, etc., but it is preferable to use silica in order to minimize the decrease in flame retardancy occurring during thickening.

The composition according to the present invention, if necessary within the range that does not impair the above properties such as flame retardancy, flexibility, durability and eco-friendliness, any one or more selected from the group consisting of a dispersing agent, an antifoaming agent, a plasticizer, a stabilizer, a fluidizing agent and a preservative It is characterized in that it further comprises an additive.

The composition according to the present invention thus prepared is excellent in flame retardancy, flexibility and eco-friendliness, so it is suitable for application as a material for covering electric wires and cables.

Hereinafter, the present invention will be described in more detail based on the following examples, but these are merely illustrative of the present invention, and the scope of the present invention is not limited thereto.

Preparation Example 1. Preparation of expanded graphite-graphene composite

Expanded graphite with a particle size of 80 mesh and high-purity graphene with a thickness of 0.3 nm (nanometers) were injected into a mixer at a weight ratio of 50:1, respectively, and dispersed for 30 minutes to expand graphite in which graphene was dispersed in layered expanded graphite. - A graphene composite was prepared.

Preparation Example 2. Preparation of silane-APP

Silane-APP in powder form was prepared by coating the surface of ammonium polyphosphate with vinyltrimethoxysilane using 0.002 to 0.02 parts by weight of vinyltrimethoxysilane per 100 parts by weight of ammonium polyphosphate. The structure of the prepared silane-APP is shown in FIG. 1 .

Preparation Example 3. Titanium pyrophosphate (TiP ₂ O ₇ ) manufacture of

A reaction mixture was prepared by injecting 22.55 wt% TiO ₂ with 29.5 wt% silane-APP and 33.96 wt% P ₂ O ₅ . The mixture was reacted by heating at 200 to 230 °C for 20 minutes, and then cooled to room temperature. Then, TiP ₂ O ₇ was prepared by injecting 13.99% by weight of NH ₄ OH to adjust the pH to 7.

Examples 1 to 5. Preparation of paint composition

In the contents shown in Table 1 below, the aqueous EVA resin and titanium dioxide were put in a high-speed stirrer, and stirred for 30 minutes to uniformly mix. Subsequently, the expanded graphite-graphene composite was added to the stirred mixture and mixed in a high-speed stirrer. Finally, silica, distilled water, and silane-APP were added, and stirred for 30 minutes or more in a high-speed stirrer for high viscosity, to prepare a coating composition according to the present invention.

ingredient
(weight%) Example 1 Example 2 Example 3 Example 4 Example 5 water-based EVA resin 55 55 55 55 55 Expanded graphite-graphene composite 10 12 14 12 12 TiO ₂ 10 9 7 9 9 silica 8 8 8 8 8 Distilled water 13 12 12 12 7 Silane-APP 4 4 4 4 4 APP - - - - - Vinyltrimethoxysilane - - - - - TiP ₂ O ₇ - - - - 5 total 100 100 100 100 100

Comparative Examples 1 to 5

As a comparative example, the case where silane-APP was not added and the case where APP and vinyltrimethoxysilane, which are raw materials for silane-APP, were added instead of silane-APP, were mixed in the contents shown in Table 2 below to obtain Example 1 The coating compositions of 5 to 5 were prepared.

Comparative Examples 6 to 8

As a comparative example, coating compositions of Comparative Examples 6 to 8 were prepared by mixing expanded graphite and graphene in place of the expanded graphite-graphene composite and expanded graphite alone in the contents shown in Table 2 below. did

ingredient
(weight%) Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Comparative Example 6 Comparative Example 7 Comparative Example 8 water-based EVA resin 55 55 55 55 55 55 55 55 Expanded graphite-graphene composite 9 12 14 12 12 - - - expanded graphite - - - - - 11 9 12 graphene One - - TiO ₂ 12 9 7 9 9 12 12 9 silica 8 8 8 8 8 8 8 8 Distilled water 17 17 17 12 7 18 17 12 Silane-APP - - - - - - - 4 APP - - - 3.994 3.994 - - - Vinyltrimethoxysilane - - - 0.006 0.006 - - - TiP ₂ O ₇ - - - - 5 - - - total 100 100 100 100 100 100 100 100

Experimental Examples 1 to 5. Characteristic evaluation according to Korea Electric Power Standard ES-8030-0001

In order to evaluate whether the composition prepared according to the above embodiment can be applied as a wire cable coating (cable burn prevention material), the Korea Electric Research Institute (KERI) tested it according to ES-8030-0001, The results obtained with the test report were described in Experimental Examples 1 to 5 below.

Specific test items of the application standard ES-8030-0001 are listed in Table 3 below.

division Item One structure and appearance 2 vertical flame test 3 Oxygen index test 4 Low chlorine test (hydrogen halide) 5 Smoke concentration test

In order to test the items of Table 3, the composition prepared in Example 1 was prepared by applying it to a cable.

1. Structure and Appearance

* Exam conditions

- Asbestos analysis: Asbestos analysis method using a one-tube microscope

- Applicable cable: 22.9 kV CNCV-W 325 mm ² Daishin Electric Wire Co., Ltd. (Manufacturing date: 2019-02)

- Application method: Brush

* Test result: Figure 5

2. Vertical flame test

* Exam conditions

- Test method: IEC 60332-3-24:2009

- Number of cables used: 2 ea

- Cable installation method: Spaced

- Number of cable layers: 1 layer

- Ignition source: ribbon gas burner

- Flame application time: 20 min

- Number of burners: 1 ea

* Test standard

- Self-extinguishing: Must show self-extinguishing when the flame is removed after burning

- Burned down: Will not burn down

* Test results: Table 4

division Test result Self-extinguishing self-extinguishing Burned down or not not burned out Extinguishing time of burning or light 1 min carbonization length 0.8 m

3. Oxygen index test

* Exam conditions

- Test method: KSMISO4589-2:1996

- Test piece shape: IV type (length: 150mm, width: 6.5mm, thickness: 2.0mm)

- Specimen pre-treatment conditions: 88 h at (23±2) ℃, (50±50) % R.H

- Specimen Ignition: Method A- Ignition of the top surface

- Oxygen index determination method: Dixon's ascending and descending method 4

* Test standard

- The oxygen index must be over 30

* Test result: 50.9

4. Low chlorine test (hydrogen halide)

* Exam conditions

- Test method: ES-6145-0018:2003-09-30, Section 5.2.5(3)

- Specimen pre-treatment conditions: (23±2) ℃, (50±5) % R.H at least 16 h

- Equivalent heating rate: (800±10) ℃, 40 min

- Maintaining temperature and time: (800±10) ℃, 20 min

*Test standard

- Hydrogen halide (excluding hydrogen fluoride) should be less than 350 mg/g

*Test result: 0.0 mg/g

5. Smoke concentration test

* Exam conditions

- Test method: ASTM E 662:2013, NIST/F-mode method

*Test standard

- Smoke concentration less than 400

* Test results: Table 5

division Test result Test piece thickness mm smoke concentration Smoke concentration per 1mm thickness Example 1 1.47 89.20 60.68 Example 2 1.60 84.57 52.85 Example 3 1.47 83.04 56.48 Example 4 1.51 73.12 48.42 Example 5 1.54 72.32 46.96

As can be seen from the above, the coating composition prepared in one embodiment of the present invention is a cable combustion prevention material required by Korea Electric Power Standards ES-8030-0001 As all of the characteristics are satisfied, it can be confirmed that it is suitable for cable sheathing.

Experimental Example 6. Evaluation of flame retardancy and thermal insulation

In order to evaluate the flame retardancy and heat insulation properties of the composition prepared according to one embodiment, a torch lamp direct heat test was conducted as shown in FIG. 2 .

In the experiment, the surface was directly heated with a torch lamp on a sheet coated with a flame retardant paint composition to a thickness of 1.0 mm, and the temperature of the rear surface was measured and evaluated with an infrared thermometer during direct heating.

As a result, as can be seen in Figure 2, the sheet coated with the composition of Example 1 according to the present invention did not generate a flame despite the direct heating of the torch, and the flame during direct heating for 2 minutes and 18 seconds The temperature of the back side of the contacted sheet was measured at 204 °C.

These results show that diffusion of flame and heat to the rear surface can be prevented by swelling the expanded graphite to form an optimal foam protective film. That is, it can be confirmed that the composition according to the present invention has excellent heat insulation properties.

Experimental Example 7. Evaluation of tensile strength and adhesion

A specimen having a width of 2.5 cm in width and 5 cm in length was prepared by curing the composition prepared according to the above example. Tensile strength and adhesive strength of the specimen were measured by the KS F 3211 measurement method using a tensile tester (UTM) and a peel tester, and the results are shown in FIGS. 6 and 7 below.

As can be seen in Figure 6, the tensile strength was improved by about 340% compared to commercially available non-foaming flame retardant paints, and as can be seen in Figure 7, the adhesive strength was also commercially available non-foaming flame retardant paints. showed an improvement of about 120% compared to

Experimental Example 8. Harmful substance test

A harmful substance test was performed on the composition prepared according to the above example, and the results are shown in FIG. 8 below.

As can be seen in Figure 8, it can be confirmed that the harmful substances are not detected or detected at a significantly lower level than the standard, thereby satisfying the Ministry of Environment's acceptance criteria.

Experimental Example 9. Evaluation of flame retardancy and insulation

In order to evaluate the flame retardancy and heat insulation properties of the compositions prepared according to the above examples and comparative examples, a torch lamp direct heat test was conducted as shown in FIG. 3 after applying the composition to a thickness of 1 mm or more on the cable sheath.

As a result, as shown in FIG. 3, in the case of the cable coated with the composition of Example 4 of the present invention, when contacted with a torch flame, compared to the case where the composition of Comparative Examples 1 and 4 was applied, the coating film was scattered. And no detachment phenomenon is observed, and it can be seen that the flame stays in place without spreading.

For this reason, when the composition of one embodiment is in contact with heat, a foam layer and a protective film for protecting and maintaining the foam layer are formed, and vinyltrimethoxysilane forming the coating of the paint is first melted by heat, When this component combines organic and inorganic components in the composition, the particles of the foamed protective film are aggregated to further improve tensile strength and adhesive strength. Such improved tensile strength and adhesion prevent scattering and detachment of the film, and can be seen as preventing the spread of flame.

On the other hand, in the case of the cable coated with the composition of Comparative Example 1, when contacted with heat, the expanded graphite-graphene composite continuously foams to form a foam layer, but since it does not contain silane-APP, there are limitations in adhesive strength and tensile strength. there is. In this case, the paint film is scattered and detached by the flame pressure of the torch lamp, and is dug like a crater, and the flame is transmitted, resulting in deterioration of flame retardancy and insulation properties of the cable.

In addition, in the case of the cable coated with the composition of Comparative Example 4, APP, vinyltrimethoxysilane, and silane were added instead of silane-APP, respectively, and the degree of damage to the coating was reduced due to the partial influence of vinyltrimethoxysilane and silane. Although it is seen to be slightly reduced compared to Comparative Example 1, scattering and detachment phenomena are still observed, and it can be seen that some of the flames have spread.

Therefore, rather than the composition of Comparative Example 4 in which APP and vinyltrimethoxysilane were added instead of silane-APP, silane-APP in which APP was coated with vinyltrimethoxysilane was added, as in the preparation example of the present invention. It can be seen that the compositions of 1 to 5 are remarkably excellent in terms of flame retardancy and heat insulation properties.

Experimental Example 10. Heat dissipation evaluation

In order to evaluate the heat dissipation characteristics of the compositions prepared according to the above examples and comparative examples, the rubber plate on the copper plate was coated with the composition prepared according to the present invention, and a hole was made in the center, as shown in FIG. 4, the copper plate A test was conducted to measure the temperature of

As a result, as can be seen in FIG. 4, in the case of (b) of FIG. 4, which is a composition including an expanded graphite-graphene composite, the thermal image temperature was relatively low at a maximum of 77.3 ° C, and the overall thermal distribution was also low. Observed. It is judged that the heat dissipation effect was shown by rapidly dissipating the heat trapped in the air layer of the expanded graphite to the outside through the dispersed graphene.

On the other hand, in the case of (c) of FIG. 4, which is a composition prepared by adding expanded graphite and graphene, respectively, the thermal imaging temperature was relatively high with a maximum thermal imaging temperature of 82.8 ° C., and the overall thermal distribution was also relatively high.

In addition, in the case of (d) of FIG. 4, which is a composition prepared by adding only expanded graphite without adding graphene, the highest thermal imaging temperature was observed at 86 °C.

Through this, it can be seen that the addition of graphene itself may have some heat dissipation effect, but the effect is very insignificant and has little effect on the overall thermal distribution. Therefore, in the case of the composition to which the expanded graphite-graphene composite prepared according to the present invention is added, it can be confirmed that the heat dissipation effect is more excellent.

Experimental Example 11. Evaluation of cable allowable current reduction rate

In order to evaluate the cable allowable current reduction rate characteristics of the composition prepared according to the above example and the comparative example, a test was requested to the Korea Electric Research Institute.

* Exam conditions

- Test method: After connecting the cable with the test product coated and the uncoated cable and passing AC 60 Hz current, compare the temperature of the two cable conductors

- Test result: Figure 9

Referring to FIG. 9, the cable allowable current reduction rate of the cable coated with the composition prepared according to the present invention was lower than that of the uncoated cable by -3.8%. Through this, it can be confirmed that the composition prepared according to the present invention is very suitable in terms of fire safety as it can reduce the load generated on the cable sheath.

So far, the present invention has been looked at with respect to its preferred embodiments. Those skilled in the art to which the present invention pertains will be able to understand that the present invention can be implemented in a modified form without departing from the essential characteristics of the present invention.

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Claims (11)

50 to 70% by weight of an aqueous ethylene vinyl acetate copolymer;
Expanded graphite-graphene composite 10 to 25% by weight;
Titanium dioxide (TiO ₂ ) 5 to 15% by weight;
Ammonium polyphosphate (APP) as a core material, 1 to 5% by weight of silane-APP coated with vinyltrimethoxysilane on its surface;
1 to 30% by weight of a thickener; and
A paint composition for covering electric wires and cables containing 1 to 20% by weight of distilled water. According to claim 1,
The expanded graphite-graphene composite is prepared by putting layered expanded graphite having a particle size of 50 to 200 mesh and graphene having a thickness of 0.1 to 0.5 nm in a mixer at a weight ratio of 50:1 to 200:1, and dispersing for 30 minutes. A paint composition for covering wire and cable, wherein graphene is dispersed in an air layer on an expanded graphite layer. According to claim 2,
The expanded graphite particle size is 80 mesh coating composition for wire and cable coating. According to claim 2,
A paint composition for coating wire and cable wherein the graphene has a thickness of 0.3 nm. According to claim 1,
The composition is titanium pyrophosphate (TiP ₂ O ₇ ) A paint composition for coating wire and cable further comprising 1 to 5% by weight. delete According to claim 1,
The silane-APP is a coating composition for wire and cable coating that is included in 0.002 to 0.02 parts by weight of vinyltrimethoxysilane per 100 parts by weight of ammonium polyphosphate. delete According to claim 1,
The thickener is 1 selected from the group consisting of polysaccharide-based thickeners, cellulose-based thickeners, acrylate thickeners, polyether-modified polyurethane thickeners, bentone-based thickeners, titanates, metal organyl-based thickeners, organic clay-based thickeners, silica, and waxes. A coating composition for covering electric wires and cables of more than one species. According to claim 9,
The thickener is a coating composition for wire and cable coating of silica. According to claim 1,
The composition further comprises at least one additive selected from the group consisting of a dispersing agent, a defoamer, a plasticizer, a stabilizer, a glidant and an antiseptic.

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