KR102176985B1 - Coating composition for wire cable coating - Google Patents

Abstract

The present invention relates to a paint composition for covering an electric wire cable, wherein the paint composition comprises: 50 to 75 wt% of an aqueous ethylene vinyl acetate resin; 10 to 25 wt% of expanded graphite; 5 to 15 wt% of titanium dioxide; 1 to 30 wt% of a thickener; and 1 to 20 wt% of distilled water. According to the present invention, an inorganic flame retardant agent is added in place of a phosphorous flame retardant agent, and thus a paint composition which does not include halogens and heavy metals and thus has excellent eco-friendly, economical, flame retardant, and flexible properties can be produced. Accordingly, the composition can be usefully coated on a moving material such as an electric wire cable.

Description

Coating composition for wire cable coating

The present invention relates to a coating composition that can be used as a wire cable coating material, and more particularly, 50 to 75% by weight of aqueous ethylene vinyl acetate resin, 10 to 25% by weight of expanded graphite, 5 to 15% by weight of titanium dioxide, thickener It relates to a coating composition for covering an electric wire cable comprising 1 to 30% by weight and 1 to 20% by weight of distilled water.

Wire cables used in electric and electronic parts require various characteristics such as flame retardancy, physical properties after heat aging, low temperature characteristics, heat resistance, oil resistance, weather resistance, etc., especially in North America countries, demanding a high level of flame retardancy. In Korea, there is a fire safety standard (NFSC 506) for combustion prevention facilities, and according to Article 7 (Application of Combustion Prevention Paint), a combustion prevention paint that satisfies the above standards must be applied to cables and wires. Is specified.

However, despite the above safety standards, most of the existing combustion inhibitors meet only the minimum standard value or are measured below the standard value. On the other hand, there are materials that satisfy all of these requirements and are economical, but they are materials containing PVC or halogen flame retardants. In the case of the above PVC, since toxic gases such as hydrogen chloride and dioxin, which can threaten the human body and the natural environment, are generated during fire or during the incineration process after use, recently developed countries such as Europe, the United States, and Japan have Regulation is being discussed. In addition, in the case of other resins containing halogen flame retardants, hydrogen halide, which is harmful to the human body and the natural environment, is generated, so there are many restrictions on use.

Recently, as a coating material for an alternative non-halogen wire capable of improving this problem, a composition in which a metal hydroxide such as magnesium hydroxide or aluminum hydroxide is added while being based on a polyolefin resin has been proposed. However, in the case of such a composition, there is a disadvantage in that physical properties such as flexibility and elongation of the electric wire are decreased because an excessive amount of metal hydroxide must be added to express flame retardant performance. Moreover, it is difficult to add powdery metal hydroxide and additives including various powdery flame retardants because they are entangled with each other.

As another method, a method of imparting flame retardancy by using polyphenylene oxide with an elastomer and a phosphorus flame retardant has been proposed, but this is a solid barrier film by forming a char by polyphenylene oxide to block heat and oxygen. Because of this system, flame retardant performance cannot be exhibited by 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 the resin for covering wires such as flexibility should have are deteriorated.

Accordingly, the present inventors confirmed a coating composition for coating an electric wire cable having excellent flame retardancy, flexibility, durability, and environment-friendliness by adding an inorganic flame-retardant system instead of a phosphorus-based flame retardant system, and completed the present invention.

Domestic registered patent No. 10-1769178 Japanese Patent Publication No. 2007-059336

Accordingly, the main object of the present invention is to provide a coating composition suitable for coating an electric wire cable, having excellent properties such as flexibility and durability as well as various physical properties required for coating an electric wire cable.

Another object of the present invention is to provide an eco-friendly electric wire cable because it has excellent flame retardant effect, excellent water resistance, weather resistance and flexibility, and does not contain halogen by applying the coating composition.

In order to achieve the above object, the present invention, in one embodiment, 50 to 75% by weight of aqueous ethylene vinyl acetate resin, 10 to 25% by weight of expanded graphite, 5 to 15% by weight of titanium dioxide, 1 to 30% by weight of a thickener and It provides a coating composition for covering an electric wire cable containing 1 to 20% by weight of distilled water.

In the composition according to the present invention, the expanded graphite and titanium dioxide are characterized in that it is included in a weight ratio of 1:1 to 2:1.

In the composition according to the present invention, the thickener is characterized in that silica.

The composition according to the present invention is characterized in that it further comprises any one or more additives selected from the group consisting of dispersing agents, antifoaming agents, plasticizers, stabilizers, fluidizing agents and preservatives.

Since the composition according to the present invention is excellent in flame retardancy, flexibility and environment-friendliness, it is suitable for application as a material for covering wires and cables.

The composition according to the present invention does not contain halogens and heavy metals by adding an inorganic flame retardant in place of the phosphorus flame retardant, so that it is possible to manufacture a paint composition that is eco-friendly and economical and excellent in flame retardancy and flexibility. Therefore, it is useful to apply the composition to a moving material such as an electric wire cable.

1 is a photograph showing a state in which the coating composition prepared in an embodiment of the present invention is applied to a cable.
2 is a photograph showing a state before and after a vertical flame test after applying the coating composition prepared in an embodiment of the present invention to a cable.

Hereinafter, the present invention will be described in more detail to aid understanding of the present invention. In this case, the terms or words used in the specification and claims should not be interpreted as being limited to a conventional or dictionary meaning, and the inventor appropriately defines the concept of the term in order to describe his own invention in the best way. It should be interpreted as a meaning and concept consistent with the technical idea of the present invention based on the principle that it can be done.

The present invention is to provide a novel coating composition, as well as reinforcement of flame retardancy, has elasticity and flexibility, and has been studied to be usable for covering wire cables.

To this end, in one embodiment of the present invention, 50 to 75% by weight of aqueous ethylene vinyl acetate resin, 10 to 25% by weight of expanded graphite, 5 to 15% by weight of titanium dioxide, 1 to 30% by weight of a thickener and 1 to 20% by weight of distilled water It provides a coating composition for coating an electric wire cable containing %.

The coating composition of the present invention includes a resin having excellent flexibility and a degree of flame retardancy in order to satisfy the flexibility required for application of an electric wire cable. In addition, it is characterized by including ethylene vinyl acetate copolymer (EVA) excellent in workability as well as flame-retardant and flame-retardant performance because it has excellent adhesion to various insulating materials and flame-retardant areas. Preferably, it may be a non-toxic, more environmentally friendly aqueous EVA resin. It is preferable that the EVA resin is contained in an amount of 50 to 75% by weight in the total composition. If the EVA resin is contained in an amount of less than 50% by weight, the flexibility of the composition may be deteriorated, and if it is included in an amount exceeding 75% by weight, mechanical properties such as strength and durability of the composition may be deteriorated.

The coating composition of the present invention, in order to overcome the limitations of the composition comprising a conventional flame retardant mainly used, for example, phosphorus-based flame retardant, metal hydrate-based flame retardant, halogen-based flame retardant, bromine-based flame retardant, flame retardant aid, etc. By including an inorganic flame retardant instead, it is characterized by securing excellent flame retardancy, flexibility, durability and eco-friendliness. The inorganic flame retardant can perform not only the role of a flame retardant but also a reinforcing agent, and thus, flame retardancy, mechanical properties, and abrasion resistance of a composition including the same can be improved.

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 the melt mixing process 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 to about 350 °C. As the inorganic flame retardant, for example, 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 a problem of low flame retardancy.

Meanwhile, the coating composition of the present invention includes expanded graphite and titanium dioxide among the inorganic flame retardants to obtain a composition in which flame retardancy, flexibility and durability of the composition are secured.

The expanded graphite is not toxic, is light, does not contain a halogen component, is insoluble in water, and does not generate toxic gases. In addition, the titanium dioxide is also eco-friendly because it does not contain a halogen component, and has the advantage of improving thermal insulation performance by accumulating heat.

The coating composition of the present invention includes the expanded graphite and titanium dioxide, and by adjusting the content and mixing ratio thereof, it is possible to improve the low flame retardant problem of the existing inorganic flame retardant, and improve the flexibility and durability of the composition. .

The coating composition of the present invention is characterized in that it contains expanded graphite as an inorganic flame retardant, particularly for blocking smoke caused by fire. When the expanded graphite is exposed to heat of 200° C. or higher, the graphite expands, thereby protecting the flame from being transmitted to the entire wire cable. In this case, the expanded graphite is preferably contained in an amount of 10 to 25% by weight in the total composition. If it is included in less than 10% by weight, the flame propagation prevention effect may be deteriorated, and if it is included in more than 25% by weight, it may be blended more than necessary to reduce the flexibility and adhesion of the composition.

The coating composition of the present invention is characterized in that it contains titanium dioxide (TiO ₂ ) as an inorganic flame retardant to improve the flame retardancy, flexibility and durability of the EVA resin. In this case, the titanium dioxide is preferably contained in an amount of 5 to 15% by weight. If the titanium dioxide is contained in an amount of less than 5% by weight, combustion resistance may be deteriorated, and when it is included in an amount exceeding 15% by weight, it may cause problems of lowering elongation, tear strength, and flexibility.

The coating composition of the present invention is characterized in that it contains the expanded graphite and titanium dioxide in a weight ratio of 1:1 to 2:1. When satisfying the above range, it is possible to secure the most suitable flame retardancy, flexibility, and durability for covering an electric wire cable.

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

The composition according to the present invention is one or more selected from the group consisting of a dispersant, a defoaming agent, a plasticizer, a stabilizer, a fluidizing agent, and an antiseptic as needed within a range that does not impair the above properties such as flame retardancy, flexibility, durability and environment-friendliness. It 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, and thus is suitable for application as a material for covering wires and cables.

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

Example 1. Preparation of coating composition

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

Ingredient (% by weight) Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Water-based EVA resin 65 65 65 65 65 65 65 Expanded graphite 14 15 15 22 - 15 9 TiO ₂ 8 7 5 - 15 3 11 Silica 11 8 8 8 8 10 10 Distilled water 2 5 7 5 12 7 5 total 100 100 100 100 100 100 100

Experimental Examples 1 to 10. Evaluation of properties

In order to evaluate whether the composition prepared in Example 1 is applicable as an electric wire cable covering (cable combustion prevention material) or not, it was tested according to the Korean Electric Power Standard Standard ES-8030-0001 at the Korea Electric Research Institute (KERI), The results obtained from the test report are described in Experimental Examples 1 to 10 below.

Specific test items of the application standard ES-8030-0001 are listed in Table 2 below.

In order to test the items in Table 2, the composition prepared in Example 1 was applied to a cable to prepare (see Fig. 1).

1. Structure and appearance

* Exam conditions

-Asbestos analysis: Asbestos analysis method using a bias microscope

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

-Application method: brushing

* Test result: Table 3

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 stacks: 1 layer

-Ignition source: Ribbon gas burner

-Flame application time: 20 min

-Number of burners: 1 ea

* Test criteria

-Self-extinguishing property: Should exhibit self-extinguishing property when the flame is removed after burning

-Burnt: Not to be burned

* Test result: Table 4 and Fig. 2

3. Oxygen Index Test

* Exam conditions

-Test method: KSMISO4589-2:1996

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

-Test specimen pretreatment conditions: 88 h at (23±2) ℃, (50±50)% R.H

-Specimen ignition: Method A- Upper surface ignition

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

* Test criteria

-Oxygen index must be 30 or higher

* Test result: 40.8

4. Low chlorine test (hydrogen halide)

* Exam conditions

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

-Test specimen pretreatment conditions: 16 h or more at (23±2) ℃, (50±5)% R.H

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

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

*Test criteria

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

*Test result: 0.0 mg/g

5. Cold heat characteristic test

* Exam conditions

-Test method: Visual inspection after cold heat treatment

-Test piece: Extracted from cable coated with flame retardant paint

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

-Cooling and heating cycle: 80 ℃ 24 h, -15 ℃ 24 h

-Cycle repetition number: 2 times

* Test criteria

-No abnormalities such as cracking, swelling, peeling and softening after cold heat treatment

* Test result: No abnormality

6. Flexural characteristic test

* Exam conditions

-Test method: Wrap it around a cylinder, bend it at 180°, bend it in the opposite direction, and inspect it with the naked eye.

-Test piece: Extracted from cable coated with flame retardant paint

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

-Cylinder size: Ф1000 mm

-Test room temperature and humidity: 20.4 ℃, 59.0% R.H.

* Test criteria

-No abnormalities such as cracking, swelling, peeling, or softening after bending test

* Test result: No abnormality

7. Smoke concentration test

* Exam conditions

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

*Test criteria

-Smoke concentration 400 or less

* Test result: Table 5

8. Oil resistance test

* Exam conditions

-Test method: After immersing in insulating oil, let it cool and inspect it

-Test piece: Extracted from cable coated with flame retardant paint

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

-Dipping condition of insulating oil: 70 ℃, 48 h

-Insulating oil: KS C2301:2015, Type 1 No. 2

-Room cooling condition: Store indoors for 24 h

* Test criteria

-No abnormalities such as cracking, swelling, peeling, or softening after oil-resistant treatment

* Test result: No abnormality

9. Salt water resistance test

* Exam conditions :

-Test method: Completely immerse the test piece in salt water at 40 ℃ to prevent it, take it out, let it cool, and inspect it

-Test piece: Extracted from cable coated with flame retardant paint

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

-Salt solution concentration: 3% (weight ratio) saline solution

-Flooding time: 10 days

-Room cooling condition: Store indoors for 24 h

* Test criteria

-No abnormalities such as cracking, peeling, or softening after salt water treatment

* Test result: No abnormality

10. Weather resistance test

* Exam conditions

-Test method: KS F2274:2002

-Test piece: Extracted from cable coated with flame retardant paint

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

-Weather resistance treatment device: Weather-o-meter (WX-A type)

-Irradiance of the surface of the specimen: 60 W/m ² (wavelength 290-400 nm)

-Black panel temperature: (63±3) ℃

-Relative humidity in the treatment device: (50±5)%

-Weather resistance treatment cycle: 102 min UV irradiation, 18 min UV irradiation and water spray

-Exposure time: 400 h

* Test criteria

-No abnormalities such as cracking, swelling, peeling, or softening after weathering treatment

* Test result: No abnormality

The comprehensive results of Experimental Examples 1 to 10 are shown in Table 6 below, which is a test report result received from the Korea Electrotechnical Research Institute.

As can be seen from the above, it can be seen that the coating composition prepared in an embodiment of the present invention satisfies all of the above characteristics required as a flame retardant of a cable, and thus is suitable for a cable sheathing use.

Experimental Example 11. Characteristics evaluation

Flame retardancy and flexibility were evaluated through the structure and appearance, vertical flame test, and flexural property test of the compositions prepared in Examples and Comparative Examples, and the results are shown in Table 7 below.

* The evaluation criteria are as follows.

◎: No abnormality at all

○: There is a little swelling in a part, but overall it is good

△: Cracking, swelling, peeling, and softening occur on a part

X: Overall severe cracking, swelling, peeling, and softening

Ingredient (% by weight) Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Structure and appearance ◎ ◎ ○ X X △ ○ Vertical flame test ◎ ◎ ○ △ X △ △ Flexural characteristic test ◎ ◎ ○ X X ○ △

As can be seen in Table 7, it can be seen that the composition prepared in the Example has significantly superior properties compared to the composition prepared in the Comparative Example, and is more suitable for cable coating.

So far, the present invention has been looked at around its preferred embodiments. Those of ordinary skill 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.

Claims (5)

50 to 75% by weight of aqueous ethylene vinyl acetate copolymer, 10 to 25% by weight of expanded graphite, 5 to 15% by weight of titanium dioxide (TiO ₂ ), 1 to 30% by weight of thickener and 1 to 20% by weight of distilled water Including,
The expanded graphite and titanium dioxide are contained in a weight ratio of 1:1 to 2:1, a coating composition for covering an electric wire cable.
delete The method of claim 1,
The thickener is 1 selected from the group consisting of a polysaccharide thickener, a cellulose thickener, an acrylate thickener, a polyether-modified polyurethane thickener, a bentone thickener, a titanate, a metal organyl thickener, an organic clay, silica and wax More than one species, coating composition for covering wires and cables.
The method of claim 3,
The thickener is silica, coating composition for coating wire cables.
The method of claim 1,
The composition further comprises at least one additive selected from the group consisting of a dispersing agent, an antifoaming agent, a plasticizer, a stabilizer, a fluidizing agent, and an antiseptic agent.

Images