Insulating composition, and cable comprising insulating layer formed therefrom

Abstract

According to the present specification, a polyolefin-based fire-resistant insulating composition can be provided. More specifically, according to the present specification, a polyolefin-based insulating composition is provided so that an insulating composition that is inexpensive and can ensure thermal-resistance and / or fire-resistance can be provided. In addition, a cable comprising an insulating layer formed therefrom can also be provided.

Description

Cable comprising an insulating composition and an insulating layer formed therefrom

[0001] The present invention relates to an insulating composition and a cable comprising an insulating layer formed therefrom. Specifically, the present invention relates to an insulating composition comprising a polyolefin-based (PO-based) resin, the composition having fire resistance and heat resistance, and to a cable comprising an insulating layer formed therefrom.

[0002] A major issue in the cable manufacturing industry today is maintaining cable behavior and performance under extreme temperature conditions, especially during fire.

[0003] To achieve this, it is necessary to ensure thermal resistance, including preventing cable deformation even at high temperatures. Furthermore, for safety, it is essential to maximize the cable's fire resistance, which can delay the spread of fire and withstand flames.

[0004] Conventionally, heat and / or fire resistance of cables was secured by wrapping a mica tape (laminated or mixed with glass fiber and mica) around the conductor and applying an insulating composition. This method prevents short circuits between adjacent conductors because the mica tape remains intact even if the insulating composition is lost during a fire.

[0005] However, the above conventional method has the problem of lowering productivity because it requires an additional process of separately winding the mica tape, and it also causes environmental and quality imbalance problems due to mica powder during the tape process.

[0006] For this purpose, a silicone resin-based refractory insulating composition can be applied by directly extruding a refractory insulating composition without introducing a mica tape in another way.

[0007] However, another method such as the above has the problem that the silicone resin-based refractory insulating composition has low mechanical properties, the general wire CV extrusion process is difficult, and the price is high, making it uneconomical.

[0008] The present inventors, in order to address the above-mentioned problems of the prior art, aim to provide a polyolefin-based fire-resistant insulating composition. More specifically, by providing the polyolefin-based insulating composition disclosed herein, they aim to provide an insulating composition that is inexpensive while ensuring heat resistance and / or fire resistance. Furthermore, they aim to provide a cable comprising an insulating layer formed from the composition.

[0009] In order to solve the above problem, the present invention discloses an insulating composition comprising a base resin and a refractory additive, wherein the base resin comprises a polyolefin resin and the refractory additive is an inorganic refractory additive.

[0010] In addition, the present invention may disclose an insulating composition in which the base resin includes EPDM (Ethylene Propylene Diene Monomer) in a range of 5 wt% to 100 wt%.

[0011] In addition, the present invention may disclose an insulating composition in which the base resin further includes POE (Polyolefin Elastomer), and the POE (Polyolefin Elastomer) is included in a range of 10 parts by weight to 1000 parts by weight relative to the EPDM.

[0012] In addition, the present invention may disclose an insulating composition in which the base resin includes at least one of EPDM (Ethylene Propylene Diene Monomer) and POE (Polyolefin Elastomer).

[0013] In addition, the present invention may disclose an insulating composition in which the inorganic refractory additive is at least one of mica, antimony trioxide (Sb2O3), clay, glass frit, and silica.

[0014] In addition, the present invention may disclose an insulating composition comprising the inorganic refractory additive in an amount of 150 to 500 parts by weight relative to 100 parts by weight of the base resin.

[0015] In addition, the present invention may disclose an insulating composition in which the inorganic refractory additive includes glass frit, and the glass frit is included in an amount of 100 to 300 parts by weight relative to 100 parts by weight of the base resin.

[0016] In addition, the present invention may disclose an insulating composition in which the inorganic refractory additive includes glass frit, and the glass frit has a softening point of 500°C or higher.

[0017] In addition, the present invention may disclose an insulating composition comprising the glass frit in an amount of 100 to 200 parts by weight relative to 100 parts by weight of the base resin.

[0018] In addition, the present invention may disclose an insulating composition in which the glass frit has an average particle diameter in the range of 1.5 µm to 4.0 µm.

[0019] The present invention discloses a fire-resistant cable comprising: a conductor; an insulating layer formed on the outside of the conductor; an insulating tape formed on the outside of the insulating layer; and a sheath layer formed on the outside of the insulating tape; wherein the insulating layer is formed of a composition of the present invention.

[0020] In addition, the present invention may disclose a fire-resistant cable further including a metal braid formed on the outside of the insulating tape and formed on the inside of the sheath layer.

[0021] In addition, the present invention may disclose a fire-resistant cable in which the insulating tape is at least one of a glass tape, a mica tape, a ceramic tape, and an aluminum tape.

[0022] According to the present specification, a polyolefin-based refractory insulating composition can be provided. More specifically, by providing a polyolefin-based insulating composition, an insulating composition that is inexpensive while still ensuring heat resistance and / or fire resistance can be provided. In addition, a refractory cable comprising an insulating layer formed from the composition can be provided.

[0023] FIG. 1 is a drawing showing a cross-sectional structure of a fire-resistant cable including an insulation layer according to an example of the present invention.

[0024] Hereinafter, the insulating composition according to the present invention and the fire-resistant cable including the insulating layer formed therefrom will be described in detail. However, the scope of the insulating composition and the fire-resistant cable is not limited by the following description.

[0025]

[0026] Among the properties mentioned in this specification, properties that are affected by temperature are properties measured at room temperature, unless otherwise specified.

[0027] In this specification, the term "room temperature" means a natural temperature that has not been heated or cooled, for example, a temperature within a range of about 10°C to 30°C, for example, a temperature of about 20°C, about 23°C, or about 25°C. In addition, unless otherwise specifically specified in this specification, the unit of temperature is ℃.

[0028] Among the properties mentioned in this specification, if pressure affects the results, unless otherwise specified, the properties are measured at atmospheric pressure. The term atmospheric pressure refers to natural pressure that is neither pressurized nor depressurized, and typically refers to a pressure within the range of approximately 700 mmHg to 800 mmHg.

[0029] Among the properties mentioned in this specification, if humidity affects the results, unless otherwise specified, the properties are properties measured at room temperature and pressure and at a humidity that is not specifically controlled.

[0030]

[0031] The present invention relates to an insulating composition.

[0032] The insulating composition disclosed herein comprises a base resin and a refractory additive.

[0033] The above base resin may include a polyolefin-based (PO-based) resin. If it corresponds to a known polyolefin-based resin, it may correspond to the base resin disclosed in this specification.

[0034] The meaning that the base resin includes a polyolefin-based resin may mean that the base resin includes 98 wt%, 98.5 wt%, 99 wt%, 99.5 wt%, or 100 wt% of the polyolefin-based resin. By including a polyolefin-based resin as the base resin of the insulating composition disclosed in the present specification, compared to the conventional invention where a silicone resin is used as the base resin, an insulating composition capable of securing fire resistance and / or heat resistance at a lower cost and / or a fire-resistant cable including an insulating layer formed therefrom can be provided.

[0035] More specifically, the base resin disclosed in the present specification may be a polyolefin-based resin, such as EPDM (Ethylene Propylene Diene Monomer) and POE (Polyolefin Elastomer), for example. More specifically, the base resin may include at least one of EPDM (Ethylene Propylene Diene Monomer) and POE (Polyolefin Elastomer).

[0036] When the base resin contains EPDM (Ethylene Propylene Diene Monomer), the lower limit of the weight % of the EPDM in the base resin may be about 5 wt%, 15 wt%, 25 wt%, 35 wt%, 45 wt%, 55 wt%, 65 wt%, 75 wt%, 85 wt%, 95 wt% or 100 wt%, and the upper limit may be about 100 wt%, 95 wt%, 85 wt%, 75 wt%, 65 wt%, 55 wt%, 45 wt%, 35 wt%, 25 wt% or 15 wt%. The weight % may be within a range that is equal to or greater than any one of the lower limits described above and at the same time less than or equal to any one of the upper limits described above.

[0037] The mixing ratio of the above EPDM is not particularly limited, but may contain 60 to 80 wt% of ethylene and 4 to 8 wt% of ethylene norbornene.

[0038] When the base resin contains POE (Polyolefin Elastomer), the lower limit of the POE weight % in the base resin may be about 10 wt%, 20 wt%, 30 wt%, 40 wt%, 50 wt%, 60 wt%, 70 wt%, 80 wt%, or 90 wt%, and the upper limit may be about 90 wt%, 70 wt%, 50 wt%, 30 wt%, or 10 wt%. The weight % may be within a range that is equal to or greater than any one of the lower limits described above, while at the same time being less than or equal to any one of the upper limits described above.

[0039] When the base resin includes EPDM (Ethylene Propylene Diene Monomer) and POE (Polyolefin Elastomer), the lower limit of the POE weight part with respect to the EPDM may be about 10 parts by weight, 30 parts by weight, 50 parts by weight, 100 parts by weight, 200 parts by weight, 500 parts by weight, 700 parts by weight, or 900 parts by weight, and the upper limit may be about 1000 parts by weight, 900 parts by weight, 500 parts by weight, 300 parts by weight, 100 parts by weight, 50 parts by weight, or 15 parts by weight. The weight part may be within a range that is equal to or greater than any one of the lower limits described above and at the same time less than or equal to any one of the upper limits described above.

[0040] The above POE may, for example, have a melting point in the range of 70°C to 100°C, preferably about 73°C. Such POE is known to have high compatibility with silicone. The base resin disclosed herein may not contain POE alone. That is, for example, if POE is contained alone, it may be difficult to secure heat resistance due to low crystallinity. However, if it contains the polyolefin resin disclosed herein, more specifically, EPDM (Ethylene Propylene Diene Monomer) at the same time in the weight range described above, heat resistance can be secured by forming a crosslinked structure.

[0041] The above refractory additive may be an inorganic refractory additive.

[0042] The above inorganic refractory additive may be, for example, one or more of mica, antimony trioxide (Sb2O3), clay, glass frit, and silica.

[0043] The lower limit of the weight of the refractory additive relative to 100 parts by weight of the base resin may be about 150 parts by weight, 160 parts by weight, 170 parts by weight, 180 parts by weight, 190 parts by weight, or 200 parts by weight, and the upper limit may be about 500 parts by weight, 400 parts by weight, 300 parts by weight, or 200 parts by weight. The weight may be within a range that is equal to or greater than any one of the lower limits described above, while at the same time being less than or equal to any one of the upper limits described above.

[0044] When the aforementioned base resin is a polyolefin resin, the covalent bonds are broken by absorbing external energy within a temperature range of 400°C to 600°C, resulting in a significant increase in the carbon ash content. This phenomenon can lead to problems such as a decrease in volume resistivity or a decrease in fire resistance. However, when the inorganic fire-resistant additive disclosed herein is included, a certain level of volume resistivity can be secured even when the polyolefin resin is included as the base resin.

[0045] In addition, the above-described inorganic refractory additive may essentially include glass frit among the aforementioned inorganic refractory additives. The insulating composition disclosed herein may have a room temperature and / or high temperature volume resistivity of a certain level or higher by including glass frit, and may secure properties such as heat resistance and / or fire resistance.

[0046] For example, if the inorganic refractory additive does not include glass frit, for example, if it contains silica alone, the extrudability of the insulating composition may be reduced due to the high melt index (MI) of silica. This reduced extrudability may make it difficult to mass-produce the insulating composition and / or the insulating layer formed therefrom. In addition, since silica contains a hydroxyl group (-OH) on its surface, it has a high moisture absorption rate and is therefore vulnerable to moisture. Therefore, if silica is contained alone as a refractory additive, the insulating composition may be subject to moisture absorption when stored at a certain temperature or for a certain period of time.

[0047] The lower limit of the weight of the glass frit relative to 100 parts by weight of the base resin may be about 100 parts by weight, 110 parts by weight, 120 parts by weight, 130 parts by weight, 140 parts by weight, or 150 parts by weight, and the upper limit may be about 300 parts by weight, 250 parts by weight, 200 parts by weight, or 150 parts by weight. The weight part may be within a range that is equal to or greater than any one of the lower limits described above, while at the same time being less than or equal to any one of the upper limits described above.

[0048] For example, since the insulating composition disclosed herein is based on a polyolefin resin that is less expensive than a conventional silicone resin-based composition, if the content of the glass frit is included below the aforementioned lower limit in order to further reduce the cost, it may be difficult to secure fire resistance or high-temperature volume resistivity.

[0049] The glass frit may have a softening point above a certain level. For example, the lower limit of the glass frit softening point may be about 500°C, 520°C, 540°C, 560°C, 580°C, 600°C, or 620°C, and the upper limit is not particularly limited, but may be about 1000°C, 900°C, 800°C, 700°C, or 650°C. The softening point may be within a range that is equal to or greater than any one of the lower limits described above, and at the same time less than or equal to any one of the upper limits described above.

[0050] If the softening point of the glass frit is below the lower limit, the ash shape may be irregular or it may be difficult to secure an appropriate degree of hardness at the same time. In addition, if the softening point of the glass frit is below the lower limit, when the cable is heated and / or ignited, the glass frit having a softening point lower than the internal temperature of the cable may be sublimated, making it difficult to secure high-temperature volume resistivity. This may indicate that the insulating composition disclosed in the present specification can secure fire resistance by including glass frit as an inorganic refractory additive, and including glass frit having a softening point that satisfies the above range.

[0051] The average particle size of the glass frit may be within a certain range. For example, the average particle size of the glass frit may be within a range of 1.5 μm to 4.0 μm, preferably within a range of 2.0 μm to 3.0 μm.

[0052] If the glass frit is not included at all, is not included in a weight portion within the above-mentioned range, or is included but does not satisfy the softening point or average particle size range, it may be difficult to secure high-temperature volume resistivity or fire resistance.

[0053] The inorganic refractory additive disclosed herein may further include a refractory additive that reacts at about 1,000°C or less while including the aforementioned glass frit. For example, the temperature of 1,000°C or less may be about 800°C or less or about 600°C or less, and the lower limit thereof is not particularly limited, but may be about 100°C or more, 200°C or more, 300°C or more, or about 400°C or more. More specifically, the refractory additive further included in the inorganic refractory additive disclosed herein may be antimony trioxide (Sb2O3). The antimony trioxide (Sb2O3) can undergo an oxidation reaction at about 1,000°C or less, specifically, about 400°C to 600°C. For example, when an additive such as a mineral is included as the refractory additive, a high temperature of 1,000°C or more may be required for ceramicization. However, the inorganic refractory additive disclosed herein further includes a refractory additive that reacts at a temperature of 1000°C or lower, thereby enabling the cable to secure char firmly even at a lower temperature when heated and / or ignited.

[0054] The insulating composition disclosed herein may further include other necessary additives in addition to the base resin and refractory additives described above. The additives are not particularly limited as long as they are additives that can be considered by those skilled in the art. For example, the other additive may be a low molecular weight wax. The other additive may be included in a lower limit of about 1 part by weight, 2 parts by weight, 3 parts by weight, 4 parts by weight, 5 parts by weight, or 6 parts by weight, or in an upper limit of about 10 parts by weight, 9 parts by weight, 8 parts by weight, 7 parts by weight, or 6 parts by weight, relative to 100 parts by weight of the base resin. The parts by weight may be within a range that is equal to or greater than any one of the lower limits described above, and at the same time less than or equal to any one of the upper limits described above. For example, when the other additive includes a low molecular weight wax in the content range described above, the fluidity and processing performance of the resin may be improved.

[0055]

[0056] The present invention relates to a fire-resistant cable.

[0057] FIG. 1 schematically illustrates a cross-sectional structure of a fire-resistant cable including an insulation layer according to an example of the present invention.

[0058] The fire-resistant cable (100) includes an insulating layer formed of the insulating composition disclosed in the above-described specification.

[0059] The fire-resistant cable (100) disclosed in this specification may include a conductor (110), an insulating layer (120) formed on the outside of the conductor, an insulating tape (130) formed on the outside of the insulating layer, and a sheath layer (140) formed on the outside of the insulating tape, and the insulating layer (120) may be an insulating layer formed of the insulating composition disclosed in this specification as described above.

[0060] The method for forming an insulating layer using the above insulating composition is not particularly limited. For example, the insulating composition may be manufactured by a molding method in which the insulating composition is fed into an extruder and extruded through a mold to form a continuous body with a cross-section of a predetermined shape. However, the method for forming an insulating layer by extruding the insulating composition is not particularly limited.

[0061] In addition, when the cable (100) includes an insulating layer (120) formed of an insulating composition disclosed in the present specification, a refractory additive included in the insulating composition, specifically glass frit, and more specifically glass frit having a softening point of 500°C or higher, is included, thereby securing high-temperature volume resistivity, thereby preventing current flow between cables during combustion and preventing flames from spreading.

[0062] In addition, the fire-resistant cable (100) may further include a metal braid (150) formed on the outside of the insulating tape (130) and formed on the inside of the sheath layer (140).

[0063] In addition, the insulating tape (130) may be at least one of glass tape, mica tape, ceramic tape, and aluminum tape. More preferably, the insulating tape (130) may be an aluminum tape. The thermal conductivity or thickness of the insulating tape is not particularly limited as long as the cable including the insulating layer manufactured from the insulating composition can secure fire resistance and / or heat resistance.

[0064] In addition, the types of the conductor (110), metal braid (150), and sheath layer (140) are not particularly limited and may be any of the known conductors, metal braids, or sheath layers widely used in the cable field. In addition, the diameter or thickness of the conductor (110), metal braid (150), and sheath layer (140) are not particularly limited as long as the cable including the insulating layer manufactured from the insulating composition can secure fire resistance and / or heat resistance.

[0065] For example, the above-mentioned insulating tape (130) or the above-mentioned metal braid (150) acts as an oxygen barrier in the cable. In this case, if the base resin of the insulating composition is polyolefin-based, a problem of accelerating carbonization of the resin may arise. However, the cable disclosed in the present specification can secure heat resistance and / or fire resistance, such as securing high-temperature volume resistivity, without the above-mentioned problem, by including an insulating layer formed of an insulating composition that satisfies the mixing amount of the above-mentioned insulating composition.

[0066]

[0067] In addition, the insulating composition disclosed in this specification, the insulating layer (120) formed with the insulating composition, or the fire-resistant cable (100) including the insulating layer can secure a certain level of physical properties.

[0068] The insulating composition disclosed herein, the insulating layer (120) formed with the insulating composition, or the fire-resistant cable (100) including the insulating layer may have a water resistance within a certain range. Water resistance refers to the degree of moisture vulnerability, and it is well known in the technical field of the present invention that moisture vulnerability must be prevented. The method for measuring the water resistance is summarized in "1. Water Resistance" in the property evaluation method of the embodiments of the present specification.

[0069] The insulating composition disclosed in this specification, the insulating layer (120) formed with the insulating composition, or the fire-resistant cable (100) including the insulating layer may have a moisture absorption rate below a certain range. For example, the upper limit of the moisture absorption rate per unit area is 1.0 mg / cm. 2 , 0.5mg / cm 2 , 0.2mg / cm 2 , 0.1mg / cm 2 , 0mg / cm 2 , -0.05mg / cm 2 , -0.1mg / cm 2 or -0.2mg / cm 2 It can be of the order of -1.0 mg / cm, and its lower limit is not particularly limited. 2 , -0.8mg / cm 2 , -0.5mg / cm 2 , -0.2mg / cm 2 , -0.1mg / cm 2 , 0mg / cm 2 or 1.0 mg / cm 2 It can be a degree. The above moisture absorption rate can be within a range that is equal to or greater than any one of the lower limits described above, and at the same time, less than or equal to any one of the upper limits described above. For example, when the water resistance is high, some of the components of the composition may actually leak out during the moisture absorption rate measurement process, and in this case, the weight after moisture absorption may decrease. In other words, when the moisture absorption rate has a negative value, it can indicate high water resistance.

[0070] The insulating composition disclosed herein, the insulating layer (120) formed of the insulating composition, or the fire-resistant cable (100) including the insulating layer can satisfy room temperature characteristics. Although it is important to secure fire resistance and / or heat resistance to prevent heat generation and / or ignition in the environment in which the insulating composition is used, it is also necessary to secure a certain level of physical properties even in a room temperature environment where such heat generation and / or ignition is not generated. For example, the insulating composition disclosed herein, the insulating layer (120) formed of the insulating composition, or the fire-resistant cable (100) including the insulating layer can have a room temperature volume resistivity, tensile strength, and elongation at a certain level or higher. The method for measuring the room temperature volume resistivity, tensile strength, and elongation is summarized in “2. Volume resistivity” and “3. Tensile strength and elongation” in the physical property evaluation method of the embodiment of the present specification.

[0071] The insulating composition disclosed herein, the insulating layer (120) formed of the insulating composition, or the fire-resistant cable (100) including the insulating layer may have a room temperature volume resistivity of a certain range or higher. For example, the lower limit of the room temperature volume resistivity may be about 1.0E+14 Ω·cm, 5.0E+14 Ω·cm, 1.0E+15 Ω·cm, 3.0E+15 Ω·cm, 4.0E+15 Ω·cm, 5.0E+15 Ω·cm, or 5.5E+15 Ω·cm, and the upper limit thereof is not particularly limited, but may be about 1.0E+18 Ω·cm, 1.0E+17 Ω·cm, 1.0E+16 Ω·cm, or 6.0E+15 Ω·cm. The above room temperature volume resistivity may be within a range that is equal to or greater than any one of the lower limits described above and at the same time less than or equal to any one of the upper limits described above.

[0072] The insulating composition disclosed in this specification, the insulating layer (120) formed with the insulating composition, or the fire-resistant cable (100) including the insulating layer may have a tensile strength above a certain range. For example, the lower limit of the tensile strength is 0.92 kgf / mm. 2 , 0.95kgf / ㎜ 2 , 1.00kgf / ㎜ 2 , 1.05kgf / ㎜ 2 , 1.10kgf / mm 2 or 1.15kgf / mm 2 It can be of the degree, and the upper limit is not specifically limited, but 5 kgf / ㎜ 2 , 4kgf / ㎜ 2 , 3kgf / ㎜ 2 , 2kgf / ㎜ 2 or 1kgf / mm 2 The tensile strength may be within a range that is equal to or greater than any one of the lower limits described above, while being less than or less than any one of the upper limits described above.

[0073] The insulating composition disclosed herein, the insulating layer (120) formed of the insulating composition, or the fire-resistant cable (100) including the insulating layer may have an elongation greater than or equal to a certain range. For example, the lower limit of the elongation may be about 120%, 140%, 160%, 180%, 200%, or 220%, and the upper limit thereof is not particularly limited, but may be about 500%, 400%, 300%, 250%, or 200%. The elongation may be within a range that is greater than or equal to any one of the lower limits described above, while at the same time being less than or equal to any one of the upper limits described above.

[0074] The insulating composition disclosed herein, the insulating layer (120) formed of the insulating composition, or the fire-resistant cable (100) including the insulating layer can ensure fire resistance. In order to ensure such fire resistance, the insulating composition must ensure appropriate ash hardness and high-temperature volume resistivity. Therefore, whether or not the fire resistance is secured can be confirmed by measuring these. The method for measuring the ash hardness and high-temperature volume resistivity is summarized in "2. Volume resistivity" and "4. Ash hardness degree" in the property evaluation method of the embodiments of the present specification.

[0075] Here, the term "high temperature" is not particularly limited and may refer to a temperature higher than the temperature at which heat generation and / or ignition occurs. Therefore, any temperature at which fire resistance and / or heat resistance is measured using the measurement method of the embodiments of this specification may correspond to the high temperature described herein. Furthermore, for example, "high temperature" in this specification may refer to 100°C or higher, 200°C or higher, 300°C or higher, 400°C or higher, or 500°C or higher.

[0076] The insulating composition disclosed herein, the insulating layer (120) formed of the insulating composition, or the fire-resistant cable (100) including the insulating layer may have an ash hardness level above a certain range. For example, the lower limit of the ash hardness level may be about 1, 2, or 3, and the upper limit thereof is not particularly limited, but may be about 5, 4.5, or 4. The ash hardness level may be within a range that is equal to or greater than any one of the lower limits described above, while at the same time being less than or equal to any one of the upper limits described above.

[0077] The insulating composition disclosed in this specification, the insulating layer (120) formed of the insulating composition, or the fire-resistant cable (100) including the insulating layer may have a high temperature volume resistivity above a certain range. For example, the lower limit of the high temperature volume resistivity may be about 1.0E+8 Ω·cm, 5.0E+8 Ω·cm, 1.0E+9 Ω·cm, 3.0E+9 Ω·cm, 1.0E+10 Ω·cm, 2.0E+10 Ω·cm, 3.0E+10 Ω·cm, 4.0E+10 Ω·cm, 5.0E+10 Ω·cm, or 6.0E+10 Ω·cm, and the upper limit is not particularly limited, but may be about 5.0E+11 Ω·cm, 1.0E+11 Ω·cm, 9.0E+10 Ω·cm, 8.0E+10 Ω·cm, 7.0E+10 Ω·cm, 6.0E+10 Ω·cm, or 5.0E+10 Ω·cm. Or it may be about 4.0E+10 Ω·cm. The high temperature volume resistivity may be within a range that is equal to or greater than any one of the lower limits described above and at the same time less than or equal to any one of the upper limits described above.

[0078] The insulating composition disclosed herein, the insulating layer (120) formed of the insulating composition, or the fire-resistant cable (100) including the insulating layer can ensure heat resistance. This heat resistance can be confirmed by the tensile residual modulus and elongation residual modulus, which represent the degree of deformation of the tensile strength and elongation when heated to a temperature above a certain level for a certain period of time. The method for measuring the tensile residual modulus and elongation residual modulus is summarized in "5. Tensile residual modulus and elongation residual modulus" in the property evaluation method of the embodiments of the present specification.

[0079] The insulating composition disclosed herein, the insulating layer (120) formed of the insulating composition, or the fire-resistant cable (100) including the insulating layer may have a tensile strength of a certain range or more. For example, the lower limit of the tensile strength may be about 70%, 80%, 90%, 100%, 110%, or 120%, and the upper limit thereof is not particularly limited, but may be about 300%, 200%, 150%, 130%, or 120%. The tensile strength may be within a range that is equal to or greater than any one of the lower limits described above, while at the same time being less than or equal to any one of the upper limits described above.

[0080] The insulating composition disclosed herein, the insulating layer (120) formed of the insulating composition, or the fire-resistant cable (100) including the insulating layer may have an elongation percentage of a certain range or more. For example, the lower limit of the elongation percentage may be about 70%, 80%, 90%, or 100%, and the upper limit thereof is not particularly limited, but may be about 200%, 150%, 130%, 120%, 110%, 100%, 90%, or 80%. The elongation percentage may be within a range that is equal to or greater than any one of the lower limits described above, while being less than or equal to any one of the upper limits described above.

[0081]

[0082] Hereinafter, the present invention will be described in more detail through specific experimental examples. However, these experimental examples are intended to exemplify the present invention and the scope of the present invention is not limited to these experimental examples.

[0083]

[0084] [Method of evaluating physical properties]

[0085] 1. Water resistance

[0086] Water resistance was evaluated by moisture absorption rate. The moisture absorption rate was measured by producing three specimens (38 mm in length × 25 mm in width × 1 mm in thickness) of the compositions of the examples and comparative examples, and the moisture absorption rate of each specimen was measured using the following method, and the final value was calculated as the average.

[0087] More specifically, the specimen was first dried in a 70°C oven for 24 hours, and then the weight (M1) was measured. Then, the specimen was again immersed in a water bath at room temperature and 90°C, the surface was wiped, and the weight (M2) was measured. Then, the specimen was dried again in a 70°C oven for 24 hours, and the weight (M3) was measured. The moisture absorption rate was calculated for the cross-sectional area (A) of the specimen using the following [moisture absorption rate calculation formula].

[0088] [Moisture absorption rate calculation formula]

[0089] If M3 > M1, (M2- M1) / A

[0090] If M3 < M1, (M2- M3) / A

[0091]

[0092] 2. Volume resistivity

[0093] The volume resistivity was measured by manufacturing each composition sample (50 mm wide × 50 mm long × 1 mm high), placing it in a metal furnace, applying a voltage of 1,000 V to the upper and lower parts of the metal furnace, and then measuring the volume resistivity at room temperature with an insulation resistance meter. After maintaining it at about 500°C for about 10 to 120 minutes, the sample was measured again with an insulation resistance meter to calculate the high-temperature volume resistivity.

[0094]

[0095] 3. Tensile strength and elongation

[0096] Tensile strength and elongation were measured for specimens manufactured with the compositions according to each of the examples and comparative examples. The specimens were prepared with a gauge length of 20 mm, a width of approximately 4 mm, and a length of approximately 75 mm, and the tensile strength and elongation were evaluated.

[0097] At this time, the tension was performed at a speed of 250 mm / min at room temperature (approximately 25°C).

[0098]

[0099] 4. Ash hardness level

[0100] Ash hardness was measured by making a specimen (50 mm wide × 50 mm long × 1 mm high) for each composition, placing the specimen in a metal furnace, and maintaining it at 500°C for about 10 to 120 minutes.

[0101]

[0102] 5. Tensile strength and elongation

[0103] After measuring the tensile strength and elongation for the specimens manufactured with the compositions according to each of the examples and comparative examples, the specimens were heated at about 135°C for about 7 days, and then the tensile strength and elongation were measured to determine the percentage of the tensile strength and elongation after heating to the tensile strength and elongation before heating.

[0104] The specimens were prepared with a width of approximately 4 mm and a length of approximately 75 mm, with a gage distance of 20 mm, and their tensile strength and elongation were evaluated.

[0105] At this time, the tension was performed at a speed of 250 mm / min at room temperature (approximately 25°C).

[0106]

[0107] Example 1

[0108] A composition was prepared by mixing 50 parts by weight of antimony trioxide (Sb2O3), 150 parts by weight of glass frit, and 6 parts by weight of other additives including wax, relative to 100 parts by weight of resin.

[0109] The above resin is an EPDM (Ethylene Propylene Diene Monomer) resin containing 71% ethylene and 5.7% ethylene norbornene, and the glass frit has an average particle size of 2.5㎛ and a softening point of 620℃.

[0110]

[0111] Example 2

[0112] The composition was prepared in the same manner as in Example 1, except that the resin was prepared by mixing EPDM and POE (Polyolefin Elastomer) in a 90:10 ratio.

[0113] The above POE is a resin with a melting temperature of 73°C.

[0114]

[0115] Example 3

[0116] The composition was prepared in the same manner as in Example 1, except that the resin was prepared by mixing EPDM and POE (Polyolefin Elastomer) in a ratio of 70:30.

[0117]

[0118] Example 4

[0119] The composition was prepared in the same manner as in Example 1, except that the resin was prepared by mixing EPDM and POE (Polyolefin Elastomer) in a 50:50 ratio.

[0120]

[0121] Example 5

[0122] The composition was prepared in the same manner as in Example 1, except that the resin was prepared by mixing EPDM and POE (Polyolefin Elastomer) in a ratio of 30:70.

[0123]

[0124] Example 6

[0125] The composition was prepared in the same manner as in Example 1, except that the resin was prepared by mixing EPDM and POE (Polyolefin Elastomer) in a ratio of 10:90.

[0126]

[0127] Comparative Example 1

[0128] A composition was prepared by mixing 150 parts by weight of antimony trioxide (Sb2O3), 50 parts by weight of clay (Trnaslink-37), and 6 parts by weight of other additives including wax, per 100 parts by weight of resin.

[0129] The above resin is an EPDM (Ethylene Propylene Diene Monomer) resin containing 71% ethylene and 5.7% ethylene norbornene.

[0130]

[0131] Comparative Example 2

[0132] The resin was prepared in the same manner as in Example 1, except that it contained only POE.

[0133]

[0134] Comparative Example 3

[0135] It was manufactured in the same manner as Comparative Example 1, except that 50 parts by weight of antimony trioxide (Sb2O3) was included, and 150 parts by weight of mica (natural mica powder) was included instead of 50 parts by weight of clay (Trnaslink-37).

[0136]

[0137] Comparative Example 4

[0138] It was manufactured in the same manner as in Comparative Example 1, except that it contained 50 parts by weight of antimony trioxide (Sb2O3) and 150 parts by weight of clay (Trnaslink-37).

[0139]

[0140] Comparative Example 5

[0141] It was manufactured in the same manner as Example 1, except that 50 parts by weight of clay (Trnaslink-37) was included instead of antimony trioxide (Sb2O3), and the glass frit had an average particle size of 2.5 ㎛ and a softening point of 460°C.

[0142]

[0143] Comparative Example 6

[0144] It was manufactured in the same manner as Example 1, except that 50 parts by weight of clay (Trnaslink-37) was included instead of antimony trioxide (Sb2O3), and the glass frit had an average particle size of 2.5 ㎛ and a softening point of 350°C.

[0145]

[0146] Comparative Example 7

[0147] It was manufactured in the same manner as Example 1, except that 100 parts by weight of glass frit was included and 50 parts by weight of silica was additionally included.

[0148] The above silica has an average particle size of 0.05㎛ and a BET surface area of ​​approximately 175m 2 / g is about right.

[0149]

[0150] Comparative Example 8

[0151] It was manufactured in the same manner as Example 1, except that 100 parts by weight of Glass Frit was included.

[0152]

[0153] The compositions of the examples and comparative examples disclosed in this specification are summarized and shown in Tables 1 and 2 below.

[0154] Example 123456EPDM1009070503010POE-1030507090Sb2O3505050505050Glass Frit(620℃)150150150150150150Other additives including wax666666

[0155] Comparative Example 12345678EPDM100-100100100100100100POE-100------Sb2O31505050505050Mica--150-----Clay50--1505050--Glass Frit(620℃)-150----100100Glass Frit(460℃)----150---Glass Frit(350℃)-----150--Silica------50-Other additives including wax66666666

[0156] The results of the physical property evaluation of the composition of the present invention (or the insulating layer manufactured from the composition) are summarized in Tables 3 and 4 below. The unit of moisture absorption rate is mg / cm 2 , the unit of volume resistivity is Ω·cm, and the unit of tensile strength is kgf / mm. 2 And the units of elongation, tensile strength and elongation are %.

[0157] Example 123456 Water absorption rate -0.246 - 0.224 - 0.185 - 0.145 - 0.107 - 0.075 Room temperature volume resistivity 5.8E + 155.7E + 155.7E + 155.7E + 155.6E + 15 High temperature volume resistivity 3.5E + 105.2E + 104.7E + 106.4E + 105.2E + 104.5E + 10 Ash Hardness3.53.53.53.53.53.5Tensile strength0.9981.0021.1251.1261.1451.189Elongation175.6185.6184.7200.6210.7220.5Tensile residual ratio110.5112.4115.4120.6124.8125.7Elongation residual ratio79.885.285.798.698.5102.5

[0158] Comparative Example 12345678 Moisture absorption rate -0.256-0.115-0.045-0.178-0.163-0.1892.400-0.013 Room temperature volume resistivity 5.6E+152.6E+152.5E+108.7E+155.8E+155.4E+154.06E+119.98E+14 High temperature volume resistivity 2.5E+077.8E+102.7E+066.4E+062.6E+10 Not measurable 8.1E+068.7E+07Ash Hardness3.53.54.03.02.0Not measurable2.52.5Tensile strength0.9631.2501.1451.2691.4691.5062.5330.982Elongation150.6240.6230.6220.8240.9260.8334.66229.4Tensile residual rate90.6135.698.780.695.67101.678.4593.6Elongation residual rate50.896.880.779.880.5687.8770.6678.5

[0159] Examples 1 to 6 satisfied the compatibility of the insulating composition disclosed in this specification, and thus satisfied the absorption characteristics, room temperature characteristics, fire resistance, and heat resistance. Comparative Example 1 did not satisfy the high-temperature volume resistivity and elongation residual capacity because it did not include Glass Frit having a softening point of 500°C or higher, and thus did not satisfy the fire resistance and heat resistance.

[0160] Comparative Example 2 did not satisfy the heat resistance because it did not satisfy the tensile residual capacity by including POE resin alone.

[0161] Comparative Examples 3 and 4 did not include Glass Frit having a softening point of 500°C or higher, and thus did not satisfy the high-temperature volume resistivity, and thus did not satisfy the fire resistance.

[0162] Comparative Example 5 did not satisfy the fire resistance because the shape of the ash was not uniform and the hardness level was not satisfied, including Glass Frit having a softening point of less than 500°C.

[0163] In Comparative Example 6, when a spark is ignited on the wire, the glass frit having a softening point lower than 500°C, which is lower than the temperature inside the wire, sublimated, and the high-temperature volume resistivity of the ash hardened material could not be measured. The fire resistance was not satisfactory.

[0164] Comparative Example 7 attempted to lower the unit cost by lowering the content of Glass Frit having a softening point of 500°C or higher and adding the same amount of silica, but the water resistance was not satisfied because the absorbency was high due to the hydroxyl groups on the silica surface, and the room temperature volume resistivity was not satisfied, so the room temperature characteristics were not satisfied either.

[0165] Comparative Example 8 attempted to lower the unit price by lowering the content of Glass Frit having a softening point of 500°C or higher, but did not satisfy the high-temperature volume resistivity and thus did not satisfy the fire resistance.

[0166]

[0167] The above description of the present invention is for illustrative purposes only, and those skilled in the art will readily appreciate that the present invention can be readily modified into other specific forms without altering the technical spirit or essential characteristics of the present invention. Therefore, the embodiments described above should be understood as illustrative in all respects and not restrictive.

[0168] The scope of the present invention is indicated by the claims described below rather than the detailed description above, and all changes or modifications derived from the meaning and scope of the claims and their equivalent concepts should be interpreted as being included in the scope of the present invention.

[0169]

[0170] [Explanation of symbols]

[0171] 100: Fire-resistant cable

[0172] 110: Conductor

[0173] 120: Insulation layer

[0174] 130: Insulating tape

[0175] 140: Sith layer

[0176] 150: Metal braiding

Claims

1. An insulating composition comprising a base resin and a refractory additive, The above base resin includes a polyolefin resin, The above refractory additive is an inorganic refractory additive, an insulating composition.

2. In paragraph 1, The above base resin is, An insulating composition comprising EPDM (Ethylene Propylene Diene Monomer) in an amount of 5 wt% to 100 wt%.

3. In paragraph 2, The above base resin further contains POE (Polyolefin Elastomer), An insulating composition comprising the above POE (Polyolefin Elastomer) in an amount of 10 to 1000 parts by weight relative to 100 parts by weight of the EPDM.

4. In paragraph 1, The above base resin is, An insulating composition comprising at least one of EPDM (Ethylene Propylene Diene Monomer) and POE (Polyolefin Elastomer).

5. In paragraph 1, The above inorganic refractory additives are, An insulating composition comprising at least one of mica, antimony trioxide (Sb2O3), clay, glass frit, and silica.

6. In paragraph 1, The above inorganic refractory additives are, An insulating composition comprising 150 to 500 parts by weight of the base resin relative to 100 parts by weight of the base resin.

7. In paragraph 1, The above inorganic refractory additive comprises glass frit, An insulating composition comprising the glass frit in an amount of 100 to 300 parts by weight relative to 100 parts by weight of the base resin.

8. In paragraph 1, The above inorganic refractory additive comprises glass frit, The above glass frit is an insulating composition having a softening point of 500°C or higher.

9. In paragraph 8, An insulating composition comprising the glass frit in an amount of 100 to 200 parts by weight relative to 100 parts by weight of the base resin.

10. In paragraph 8, The above glass frit is an insulating composition having an average particle diameter in the range of 1.5 ㎛ to 4.0 ㎛.

11. Conductor; An insulating layer formed on the outer side of the conductor; Insulating tape formed on the outside of the insulating layer; and Including a sheath layer formed on the outside of the above insulating tape; A fire-resistant cable, wherein the insulating layer is formed from any one of the insulating compositions of claims 1 to 10.

12. In paragraph 11, A fire-resistant cable further comprising a metal braid formed on the outside of the insulating tape and formed on the inside of the sheath layer.

13. In paragraph 11, The above-mentioned insulating tape is a fire-resistant cable, wherein at least one of glass tape, mica tape, ceramic tape, and aluminum tape is used.

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