KR20220061038A - Non-crosslinked insulating composition and power cable having an insulating layer formed from the same - Google Patents

Abstract

The present invention relates to a non-crosslinked insulating composition and a power cable having an insulating layer formed therefrom, and more specifically, relates to a non-crosslinked insulating composition which satisfies high heat resistance, electrical properties, mechanical properties, flame retardancy, extrusion properties, and the like required by the insulating layer of a wire for indoor wiring as a non-crosslinked, recyclable eco-friendly material and a power cable having an insulating layer formed therefrom.

Description

Non-crosslinked insulating composition and power cable having an insulating layer formed therefrom

The present invention relates to a power cable having a non-crosslinked insulating composition and an insulating layer formed therefrom. Specifically, the present invention relates to a non-crosslinked insulating composition that simultaneously satisfies high heat resistance, electrical properties, mechanical properties, flame retardancy, extrudability, etc. required for an insulating layer of an indoor wiring wire as an eco-friendly material that can be recycled as a non-crosslinked type, and from the same It relates to a power cable having an insulating layer formed thereon.

A cable used for general electrical work or electrical equipment wiring, indoor wiring, etc. may include a conductor and an insulating layer surrounding the conductor.

Conventionally, non-crosslinked polyvinyl chloride (PVC) resin and non-crosslinked polyolefin (PO) resin were mixed and used for the insulation layer material of low-voltage and medium-voltage cables used for indoor wiring, etc., but in case of fire, the human body The use of cross-linked polyolefin (PO) resin has become common because high heat resistance is required for the insulating layer material due to the leakage of toxic gases harmful to the body.

However, since the cross-linked polyolefin (PO) resin is in a cross-linked form, when the life of a cable including an insulating layer made from an insulating composition containing the resin is over, the resin constituting the insulating layer cannot be recycled and must be disposed of by incineration. No, it is not environmentally friendly.

Therefore, as a non-crosslinked type, recyclable eco-friendly material, a non-crosslinked insulating composition that simultaneously satisfies the high heat resistance, electrical properties, mechanical properties, flame retardancy, extrudability, etc. required for the insulating layer of an indoor wiring wire and an insulating layer formed therefrom There is an urgent need for a power cable to have.

An object of the present invention is to provide a non-crosslinked insulating composition that satisfies the high heat resistance required for an insulating layer of a low voltage electric wire for indoor wiring as an eco-friendly material that can be recycled as a non-crosslinked type, and a power cable having an insulating layer formed therefrom.

In addition, the present invention provides a power cable having a non-crosslinked insulating composition that simultaneously satisfies not only high heat resistance but also electrical properties, mechanical properties, flame retardancy, extrudability, etc. required for an insulating layer of an indoor wiring wire, and an insulating layer formed therefrom. aim to

In order to solve the above problems, the present invention,

A non-crosslinked insulating composition, comprising polyolefin resin grafted with polypropylene, ethylene copolymer and maleic anhydride as a base resin, and a flame retardant, and having a melt flow rate (MFR) of 20 to 26 g/10 min (190 ° C.) , 21.6 kg) and having a minimum point torque (ML) (190° C.) of 1.1 to 1.4 lb-in.

Here, it provides a non-crosslinked insulating composition, characterized in that the relationship between the melt flow rate (MFR) and the lowest point torque (ML) satisfies the following Equation (3).

[Equation 3]

In addition, in differential scanning calorimetry (DSC) of the non-crosslinked insulating composition, at least one peak at 150 to 170 ° C, and at least one peak at 70 to 100 ° C. , to provide a non-crosslinked insulating composition.

And, the polypropylene resin includes a propylene block copolymer having a melting point of 150 to 170° C., and the ethylene copolymer includes two types of polyolefin elastomers (POE) having a melting point of 60 to 100° C. and different melting points from each other, The maleic anhydride-grafted polyolefin resin provides a non-crosslinked insulating composition comprising a maleic anhydride-grafted polyolefin elastomer having a melting point of 70 to 90°C.

Here, the polypropylene resin provides a non-crosslinked insulating composition comprising a propylene block copolymer polymerized under a metallocene catalyst.

In addition, the ethylene copolymer comprises a low melting point polyolefin elastomer (POE) having a melting point of 60 to 70 °C and a high melting point polyolefin elastomer (POE) having a melting point of 75 to 100 °C, providing a non-crosslinked insulating composition do.

And, based on 100 parts by weight of the base resin, the content of the polypropylene resin is 20 to 40 parts by weight, the content of the ethylene copolymer is 40 to 65 parts by weight, and the maleic anhydride is grafted (grafted) The content of the polyolefin resin provides a non-crosslinked insulating composition, characterized in that 10 to 20 parts by weight.

Furthermore, the high melting point polyolefin elastomer (POE) and the low melting point polyolefin elastomer (POE) provide a non-crosslinked insulated cable, characterized in that it satisfies Equations 1 and 2 below.

[Equation 1]

[Equation 2]

In Equations 1 and 2 above,

x ₁ , MI ₁ and Tm ₁ are the content (g), melt index (g/10min) and melting point (°C) of the high melting point polyolefin elastomer, respectively,

x ₂ , MI ₂ and Tm ₂ are the content (g), melt index (g/10min) and melting point (°C) of the low melting point polyolefin elastomer, respectively.

On the other hand, the flame retardant provides a non-crosslinked insulating composition comprising a metal hydroxide flame retardant and a nitrogen-based flame retardant auxiliary agent.

Here, the nitrogen-based flame retardant aid provides a non-crosslinked insulating composition, characterized in that it comprises melamine cyanurate.

In addition, in thermogravimetric analysis (TGA) of the insulating composition, the content of ash is 38.5 to 40.5 wt% based on the total weight of the insulating composition, and the specific gravity of the insulating composition is 1.457 to 1.470 g/cm ³ It provides a non-crosslinked insulating composition, characterized in that.

In addition, based on 100 parts by weight of the base resin, the content of the metal hydroxide flame retardant is 150 to 190 parts by weight, and the content of the nitrogen-based flame retardant auxiliary is 5 to 20 parts by weight, it provides a non-crosslinked insulating composition .

And, based on 100 parts by weight of the base resin, calcium carbonate (CaCO ₃ ) It provides a non-crosslinked insulating composition comprising 1 to 20 parts by weight as a filler.

Here, based on 100 parts by weight of the base resin, the total content of the flame retardant and the filler is 150 to 200 parts by weight, it provides a non-crosslinked insulating composition.

In addition, based on 100 parts by weight of the base resin, 0.5 to 5 parts by weight of a lubricant and 0.1 to 10 parts by weight of other additives are included, and the other additives are at least one selected from the group consisting of antioxidants, moisture absorbents, processing stabilizers and pigments. It provides a non-crosslinked insulating composition, characterized in that it comprises.

On the other hand, conductor; And it provides a non-crosslinked insulated wire surrounding the conductor and comprising an insulating layer formed from the insulating composition of claim 1 or 2.

The non-crosslinked insulating composition according to the present invention can be recycled by using a non-crosslinked type resin as a base resin, and at the same time exhibits an excellent effect of satisfying high heat resistance through a combination of a specific base resin.

In addition, the non-crosslinked insulating composition according to the present invention has excellent heat resistance and electrical properties, mechanical properties, flame retardancy, extrudability, etc. required for the insulation layer of an indoor wiring wire by controlling the mixing ratio of a specific base resin and additives. show the effect.

1 schematically shows a cross-sectional structure of a power cable according to the present invention.
Figure 2 schematically shows a cross-sectional view of the insulating layer extrusion die of the power cable according to the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the present invention is not limited to the embodiments described herein and may be embodied in other forms. Rather, the embodiments introduced herein are provided so that the disclosed content may be thorough and complete, and the spirit of the present invention may be sufficiently conveyed to those skilled in the art. Like reference numerals refer to like elements throughout.

1 schematically shows a cross-sectional structure of a power cable according to the present invention.

1 , the power cable having flame retardancy and water resistance according to the present invention may include a conductor 100 and an insulating layer 200 surrounding the conductor 100 .

The conductor 100 may be made of a conductive material through which an electric current can flow, for example, a metal such as copper or aluminum, and may be a single wire or a stranded wire in which a plurality of wire wires are combined, and the diameter is the capacity of the cable including the same can be appropriately selected by

The insulating layer 200 may be formed from an insulating composition including a base resin, a flame retardant, a filler, a lubricant, and other additives, and the base resin is a polypropylene resin, ethylene copolymer, and maleic anhydride grafted ( grafted) polyolefin resin.

The insulating composition may have one or more peaks at 150 to 170° C. and one or more peaks at 70 to 100° C. during differential scanning calorimetry (DSC). That is, the insulating composition may include, as a base resin, at least one resin having a melting point (Tm) of 150 to 170° C. and at least one resin having a melting point (Tm) of 70 to 100° C., whereby the heat resistance of the insulating composition , elongation, extrudability, compatibility with additives such as flame retardants to be described later can all be improved.

Here, in differential scanning calorimetry (DSC), 10 mg of an insulating composition sample is set in an analysis facility and heated at a rate of 10° C./min from 20° C. to 220° C. in a nitrogen atmosphere, and then 10° C./min from 220° C. to 20° C. Cooling at a rate of , and heating again at a rate of 10°C/min from 20°C to 220°C, check the temperature at which the peak occurs. The reason for repeatedly performing the temperature increase twice is to confirm the intrinsic value of the insulating composition by deleting the heat history applied to the insulating composition during the first heating.

Specifically, the polypropylene resin may have a melting point of 150 to 170°C. Here, when the melting point of the polypropylene resin is less than 150 ℃, the heat resistance of the insulating composition may be greatly reduced, whereas if it exceeds 170 ℃, elongation, extrudability, etc. of the insulating composition may be reduced.

The polypropylene resin may include, for example, propylene homopolymer and/or propylene copolymer, preferably propylene monomer with ethylene and 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene , 1-heptene, 1-octene, etc. may include a propylene block copolymer formed by copolymerization of at least one comonomer selected from the group consisting of C _4-12 alpha-olefins.

The polypropylene resin may be polymerized under conventional stereo-specific Ziegler-Natta catalysts, metallocene catalysts, constrained geometry catalysts, other organometallic or coordination catalysts, preferably under Ziegler-Natta catalyst or metallocene catalyst. can be

Here, the metallocene is a generic term for bis(cyclopentaidenyl)metal, which is a new organometallic compound in which cyclopentadiene and a transition metal are combined in a sandwich structure, and the general formula of the simplest structure is M(C ₅ H ₅ ) ₂ (here , M is Ti, V, Cr, Fe, Co, Ni, Ru, Zr, Hf, etc.).

Since the polypropylene resin polymerized under the metallocene catalyst has a low catalyst residual amount of about 200 to 700 ppm, deterioration of the electrical properties of the insulating composition including the polypropylene resin by the catalyst residual amount can be suppressed or minimized. there is.

The ethylene copolymer may include two types of polyolefin elastomers (POE) having different melting points, and the polyolefin elastomer (POE) has excellent compatibility with the polypropylene resin, and in particular has a higher degree of crystallinity than the polypropylene resin. It has excellent loading properties with additives such as flame retardants, so even when a large amount of flame retardant is added to the insulating layer, flame retardancy is improved by uniform dispersion of the flame retardant, and deterioration of mechanical properties, flexibility, etc. can be avoided or minimized. there is.

The two types of polyolefin elastomers (POE) may include, for example, a low-melting polyolefin elastomer (POE) having a melting point of 60 to 70°C and a high-melting polyolefin elastomer (POE) having a melting point of 75 to 100°C.

Here, when the melting point of the low melting point polyolefin elastomer (POE) is less than 60° C., the heat resistance of the insulating composition may decrease, whereas when the melting point of the high melting point polyolefin elastomer (POE) is more than 100° C., extrusion of the insulating composition The properties may be reduced, and compatibility between the insulating composition and additives such as flame retardants may be reduced.

The high melting point polyolefin elastomer (POE) and the low melting point polyolefin elastomer (POE) may simultaneously satisfy the relationships of Equations 1 and 2 below.

[Equation 1]

[Equation 2]

In Equations 1 and 2 above,

x ₁ , MI ₁ and Tm ₁ are the content (g), melt index (g/10min) and melting point (°C) of the high melting point polyolefin elastomer, respectively,

x ₂ , MI ₂ and Tm ₂ are the content (g), melt index (g/10min) and melting point (°C) of the low melting point polyolefin elastomer, respectively.

Equation 1 is an expression showing the relationship between the content, melt index, and melting point of the high melting point polyolefin elastomer and the low melting point polyolefin elastomer, ) is within a certain range, it means that physical properties such as extrudability, electrical, and mechanical properties of the entire insulating composition can be satisfied.

On the other hand, Equation 2 is an expression showing the correlation between the melting point and content of the high melting point polyolefin elastomer and the low melting point polyolefin elastomer. If the content of the high melting point resin is too large, the filler loading property is deteriorated, and the physical properties such as workability and mechanical properties are lowered. This means that the content of the low melting point resin must be guaranteed to some extent.

Accordingly, the insulating composition can simultaneously improve flame retardancy, mechanical properties, and flexibility, which are in a trade-off relationship with each other.

The polyolefin resin grafted with maleic anhydride may have a melting point of 70 to 90° C., for example, may include a polyolefin elastomer grafted with maleic anhydride, and additives such as a flame retardant included in the insulation composition; Even when a large amount of a flame retardant is added to the insulating layer by further improving the compatibility of the flame retardant, it is possible to improve the flame retardancy by uniform dispersion of the flame retardant and further improve mechanical properties, flexibility, and the like.

Here, when the melting point of the polyolefin resin grafted with maleic anhydride is less than 70° C., the heat resistance of the insulating composition may be insufficient, whereas when it exceeds 90° C., compatibility with additives such as flame retardants may be insufficient.

The present inventors have found that the insulating composition according to the present invention has a melting flow rate (MFR) of 20 to 26 g/10 min (190° C., 21.6 kg) on the premise that it contains the above-described non-crosslinking type specific base resin. When controlled to, and the lowest point torque (melting level; ML) (190 ℃) is adjusted to 1.1 to 1.4 lb-in, preferably, the relationship between the melt flow rate (MFR) and the lowest point torque (ML) is mathematical When Equation 3 is satisfied, electrical properties, mechanical properties, extrudability, etc. required for the insulation layer of the electric wire for indoor wiring are satisfied, and at the same time, despite the addition of a flame retardant in an amount to realize the desired flame retardancy, the properties are below the standard. The present invention was completed by experimentally confirming that there is no deterioration. Specifically, when the melt flow index (MFR) is high, the flowability is good, and conversely, the minimum torque (ML) shows a low tendency, so it shows a conflicting relationship, and this relationship was confirmed as shown in Equation 3 below .

[Equation 3]

Here, the melt flow rate (MFR) means the mass of the insulating composition extruded within a given time through a predetermined orifice under specific conditions, and in the present invention, the insulating composition extruded for 10 minutes at 190 ° C. of mass (g/10min).

Here, the lowest point torque (ML) is one of the values measured through a moving-die rheonmeter (MDR) equipment, and refers to a lower limit among torque values that change over time when the composition is rotated at the same angular velocity.

In particular, when the melt flow rate (MFR) of the insulating composition according to the present invention is less than 20 g/10min or the lowest torque (ML) is more than 1.4 lb-in, if the extrusion line speed is increased according to the increase in the load of the insulating composition during extrusion, the internal Problems with poor extrudability such as generation of bubbles in the extrudate due to heat generation may occur.

On the other hand, when the melt flow index (MFR) of the insulating composition according to the present invention is greater than 26 g/10min or the lowest torque (ML) is less than 1.1 lb-in, the melting index of the base resin itself included in the insulating composition ; This may occur when the MI) is high or the content of processing aids such as lubricants is high. When the flowability (MI) of the base resin itself is high, the properties of the insulation composition may decrease, and the content of processing aids may be reduced. If this is high, a problem of poor extrudability may occur, such as slippage of the insulating composition in the extruder and a decrease in the extrusion amount.

For example, based on 100 parts by weight of the base resin, the content of the polypropylene resin may be 20 to 40 parts by weight, the content of the ethylene copolymer may be 40 to 65 parts by weight, and the maleic anhydride is grafted. The content of the (grafted) polyolefin resin may be 10 to 20 parts by weight.

Here, when the content of the polypropylene resin is less than the standard, mechanical properties, heat resistance, heat deformation properties, etc. of the insulating layer may be deteriorated, and when the content of the ethylene copolymer is less than the standard, the extrudability of the insulating composition, electrical Physical properties such as mechanical properties may be reduced, and in particular, when the content of the polyolefin resin grafted with maleic anhydride is less than the standard, the coupling property between the additive such as a flame retardant and the base resin is lowered, so that the insulation The overall mechanical properties, flame retardancy, etc. of the composition may be deteriorated.

On the other hand, when the content of the polypropylene resin exceeds the standard, the filler loading property of the insulating composition with respect to a flame retardant or the like is insufficient, and mechanical properties such as elongation of an insulating layer formed from the insulating composition may be reduced.

In addition, when the content of the ethylene copolymer exceeds the standard, since the melting point is relatively lower than that of the polypropylene resin, the heat resistance of the insulating composition may be lowered, and the hardness of the insulating layer formed from the insulating composition is lowered and heated. Deformation properties are more likely to deteriorate, and in particular, when the content of polyolefin resin grafted with maleic anhydride exceeds the standard, the room temperature elongation rate of the insulating layer decreases, and the extrusion load during extrusion of the insulating composition increases. Problems such as deterioration of workability may be caused.

The flame retardant may include a non-halogen flame retardant such as a metal hydroxide flame retardant such as magnesium hydroxide, aluminum hydroxide, and brushite, and a nitrogen-based flame retardant auxiliary such as melamine cyanurate.

However, since brushite is inferior in flame retardancy compared to magnesium hydroxide and aluminum hydroxide, it is preferable to add it in an amount of 30% by weight or less based on the total weight of the flame retardant when using a mixture of brushite.

As the flame retardant, inorganic particles of metal hydroxide such as magnesium hydroxide are hydrophilic having high surface energy, whereas base resins such as polypropylene are hydrophobic having low surface energy, so the inorganic particles have good dispersibility in the base resin. Also, the water resistance of the insulating layer may be lowered, thereby adversely affecting electrical properties.

Therefore, in order to solve this problem, it is preferable that the surface of the inorganic particles such as magnesium hydroxide be hydrophobically treated with vinylsilane, stearic acid, oleic acid, aminopolysiloxane, titanate-based coupling agent, or the like.

When the inorganic particles are surface-treated with vinyl silane, etc., hydrolyzable groups such as vinyl silane are attached by chemical bonding to the surface of inorganic particles such as magnesium hydroxide by condensation reaction, and the silane group reacts with the base resin to have excellent dispersibility can be obtained.

The insulating composition has a content of 38.5 to 40.5 wt% of ash excluding burned organic matter during thermogravimetric analysis (TGA) based on its total weight, and the specific gravity of the insulating composition is 1.457 to 1.470 g/cm ³ days can Here, when the ash content is less than 38.5% by weight or the specific gravity is less than 1.457 g/cm ³ , the flame retardancy of the insulating composition may be significantly reduced, whereas the ash content is greater than 40.5% by weight or the When the specific gravity exceeds 1.470 g/cm ³ , mechanical properties, extrudability, and the like of the insulating composition may be significantly reduced.

Here, the ash content can be measured through thermogravimetric analysis (TGA), and the thermogravimetric analysis (TGA) is performed by setting 10 mg of an insulating composition sample in an analysis facility and from 20° C. to 800° C. under a nitrogen atmosphere. It is heated at a rate of ℃/min, and when it reaches 800℃, it is changed to an oxygen atmosphere and heated to 900℃ at a rate of 10℃/min. In this process, the remaining material is oxidized and remains ash This can be done by measuring the weight of On the other hand, the specific gravity of the insulating composition can be measured by producing a press sheet of 1 mm.

Specifically, based on 100 parts by weight of the base resin, the content of the metal hydroxide as a flame retardant, in particular magnesium hydroxide, may be 150 to 190 parts by weight, and the content of the nitrogen-based flame retardant aid, particularly melamine cyanurate, which is a flame retardant auxiliary, is the insulation Based on the total weight of the composition, it may be 5% by weight or more, for example, 5 to 20% by weight. Here, if the content of the flame retardant or the flame retardant auxiliary agent is less than the standard, the flame retardancy of the insulating layer may be insufficient, whereas if it exceeds the standard, the extrudability, elongation, etc. of the insulating layer may be greatly reduced.

The filler, that is, the filler is added to reduce the manufacturing cost while avoiding or minimizing deterioration of the physical properties of the insulating layer. For example, calcium carbonate (CaCO ₃ ) may be included, and based on 100 parts by weight of the base resin As such, it may be included in an amount of 1 to 20 parts by weight.

Meanwhile, the total content of the flame retardant and the filler may be 150 to 200 parts by weight based on 100 parts by weight of the base resin, wherein the weight ratio of the flame retardant to the filler may be 80:20 to 100:0.

The lubricant may include wax, a coupling agent, etc., and may be applied in an amount of 0.5 to 5 parts by weight based on 100 parts by weight of the base resin, and the other additives may include antioxidants, moisture absorbents, processing stabilizers, It may include a pigment and the like, and may be added in an amount of 0.1 to 10 parts by weight based on 100 parts by weight of the base resin.

[Example]

1. Preparation example

After putting into a batch type mixer such as an internal mixer, kneader, VIC mixer, etc. with the components and contents shown in Table 1 below, heat is generated above the melting point of the raw material by frictional heat through rotor rotation to prepare an insulating composition, and the final temperature When the temperature reached 180 ℃, it was injected into a pellet maker (product name: Feeder-ruder) and extruded under the conditions of a screw (170 ℃), a cylinder (170 ℃), and an extrusion die (200 ℃) to prepare an insulation composition in the form of pellets. Then, an insulating specimen was prepared therefrom. In addition, a cable specimen was prepared by extruding the insulating composition in the form of pellets under the conditions of a cylinder (170° C.) and an extrusion die (180° C.) on a 2.5 SQ single-wire conductor preheated to 120° C.

Here, as shown in FIG. 2, the extrusion die includes a nipple 10 for fixing and transporting a conductor and a die 20 provided outside the nipple 10 to form a flow path of the insulating composition extruded into the conductor. In particular, the length of the die land between the nipple tip 11 from which the conductor is discharged from the nipple 10 and the die tip 21 from which the cable with the insulating layer extruded from the die 20 is drawn ( L) is designed to be 8 to 12 times the inner diameter of the nipple 10, which is the outer diameter of the conductor, and the flow path angle (θ ₁ ), which is an angle at which the flow path of the insulating composition is inclined with respect to the conductor center line, is 25 to 50°, and the die land The die land angle (θ ₂ ), which is an angle at which the inner wall of the die 12 is inclined with respect to the conductor centerline, is 4 to 10°, and a double-angle die is used.

The unit of the content shown in Table 1 below is a part by weight.

Example comparative example One 2 One 2 3 4 5 6 7 8 resin 1 23 30 50 25 25 30 30 30 30 resin 2 40 32 30 35 32 32 50 32 32 resin 3 20 25 10 35 25 25 30 25 25 resin 4 20 resin 5 40 resin 6 15 13 10 5 15 13 13 20 13 13 Flame Retardant 1 113 150 113 93 113 130 160 113 150 210 Flame Retardant 2 60 60 80 60 60 Flame Retardant 3 17 20 17 17 17 17 5 17 filler 20 50 20 other additives 9 9 9 9 9 9 9 9 9 9

Resin 1: Block copolymer polypropylene, melting point 165℃, MI 4.0

Resin 2: Polyolefin elastomer, melting point 62℃, MI 5.0

Resin 3: Polyolefin elastomer, melting point 98℃, MI 8.0

Resin 4: Polyolefin elastomer, melting point 74℃, MI 1.0

Resin 5: Polyolefin elastomer, melting point 68℃, MI 3.0

Resin 6: Maleic anhydride grafted polyolefin elastomer

Flame retardant 1: silane-coated magnesium hydroxide flame retardant

Flame retardant 2: Silane-coated brushite flame retardant

Flame retardant 3: Melamine cyanurate

Filler 1: Lubricant coated calcium carbonate

Other additives: antioxidants and lubricants

2. Physical property evaluation

1) Room temperature mechanical property evaluation

Tensile strength and elongation were measured at a rate of 250 mm/min for each insulating layer specimen in Examples and Comparative Examples. Tensile strength should be 10 N/㎟ or more, and elongation should be 125% or more.

2) Heat resistance evaluation

Each of the insulating layer specimens of Examples and Comparative Examples were kept in an oven at 135 ° C. for one week, and then the tensile strength and elongation were measured to calculate the residual ratio (= properties after heating / properties at room temperature * 100) compared to the tensile strength and elongation at room temperature. The tensile residual ratio and the extension residual ratio should be 70 to 130%, respectively.

3) Flame retardant evaluation

In accordance with the standard IEC 60332-1, one cable specimen is fixed vertically from the ground, and a burner of the specified standard is placed at an angle of 45° to the cable specimen, and the flame is applied for 60 seconds. The length of the part was measured 5 times, and the length should be at least 50 mm from the upper indicator tape.

4) DC electrical characteristics evaluation

In accordance with the standard IEC 62930, the cable specimen was immersed in saline at 85°C and 1% concentration, and after applying a voltage of 1kV DC, it was evaluated whether insulation breakdown occurred for 240 hours.

5) Extrusion evaluation

The melt flow rate (MFR) was measured in the existing melt index (MI) evaluation facility, and the lowest point torque (ML) was measured using the MDR (melt-draw ratio) evaluation facility.

Specifically, the melt flow rate (MFR) follows the ASTM D1248 regulations, and when a load of 21.6 kg is applied at 190°C after filling and melting an insulating specimen in a barrel with a capillary disposed below and an orifice formed It can be obtained by measuring the mass (g/10min) of the insulating composition discharged down through the capillary for 10 minutes.

In addition, the MDR evaluation facility is a facility for evaluating the high-temperature crosslinking properties of cross-linked materials in general. An insulating specimen is sandwiched between the upper and lower disks, and the lower disk is rotated repeatedly at a predetermined angular speed at 190 ° C. The applied torque is measured, and the minimum value (lb-in) of the measured torque is the lowest point torque (ML).

Here, the melt flow rate (MFR) should be 20 to 26 g/10min, and the lowest point torque (ML) should be 1.1 to 1.3 lb-in.

The measurement results of the physical properties are shown in Table 2 below.

Experimental conditions Example comparative example One 2 One 2 3 4 5 6 7 8 room temperature
The tensile strength
(1N/mm ² ) RT
(1N/mm ² ↑) 13.39 14.27 11.61 8.23 12.78 12.70 14.57 14.16 13.16 15.11 Elongation (%) RT
(125%↑) 173.5 157.1 105.1 173.3 168.7 166.8 161.8 165.5 181.4 121.3 Tensile residual rate after heating
(%) 135℃/168h
(70-130) 100.0 102.3 98.7 111.8 92.7 105.3 101.7 NG 99.3 97.2 Residual kidney rate after heating
(%) 135℃/168h
(70-130) 80.1 83.1 79.7 78.4 83.5 81.2 84.6 NG 87.9 91.5 Flame retardant (IEC60332-1) RT(Pass) Pass Pass Fail Fail Pass Fail Fail Pass Fail Pass DC withstand voltage (IEC62930) 85℃ 1% brine
DC 1kV/
240hr (No Breakdown) Pass Pass Pass Fail Pass Pass Pass Fail Pass Fail Extrudability - MFR 190℃/
21.6kg
(20-26) 23.4 24.7 22.7 22.5 10.0 25.8 23.0 20.8 24.7 18.4 Extrudability-ML 190℃
(1.1~1.3) 1.24 1.18 1.31 1.26 1.75 1.12 1.21 1.35 1.21 1.47 Compound Ash
(weight%) 38.5~40.5 40.2 38.8 40.2 40.2 40.2 38.8 41.6 40.2 37.2 41.6 compound weight
(g/cm ³ ) 1.457~1.470 1.4597 1.4657 1.4645 1.4632 1.4612 1.4925 1.4748 1.4550 1.441 1.486

As shown in Table 2 above, the insulating compositions of Examples 1 and 2 according to the present invention are environmentally friendly, including a non-crosslinked type base resin, and have high heat resistance required in the insulating layer of an indoor wiring wire, as well as electrical properties, It was confirmed that all of the mechanical properties, flame retardancy, extrudability, etc. were satisfied.

On the other hand, in the insulation composition of Comparative Example 1, the content of the polypropylene resin exceeds the standard, so that the content of the crystalline resin is excessive and the filler loading properties for the flame retardant and the filler are lowered, so that the room temperature elongation, flame retardancy, extrudability, etc. are lowered. Confirmed.

In addition, in the insulation composition of Comparative Example 2, the content of the polyolefin resin grafted with maleic anhydride was less than the standard, and the filler loading properties for flame retardants and fillers were insufficient. .

And, the insulating composition of Comparative Example 3 is an ethylene copolymer, and the melt index of the polyolefin elastomer (POE) is insufficient, so that the extrudability is lowered. This was so severe that a phenomenon in which air bubbles were generated inside the insulating layer was observed.

Furthermore, in the insulating composition of Comparative Example 4, it was confirmed that the manufacturing cost and other physical properties were satisfied by replacing a portion of the metal hydroxide flame retardant with a calcium carbonate filler, but the flame retardant properties were greatly reduced.

In addition, it was confirmed that the insulating composition of Comparative Example 5 did not satisfy some of the flame retardant properties required by the standard IEC 60332-1 because the content of the melamine cyanurate flame retardant aid was below the standard.

In addition, the insulation composition of Comparative Example 6 did not apply a polypropylene resin, so the insulation layer melted and flowed down when heated at a high temperature in a non-crosslinked state, making it impossible to evaluate, and did not satisfy the high-temperature salt water DC withstand voltage test.

Finally, the insulating composition of Comparative Example 7 had a compound ash content of less than 38.5 wt% and a specific gravity of less than 1.457 g/cm ³ , so there was a problem in flame retardancy, whereas the insulating composition of Comparative Example 8 had compound ash (ash) The content exceeded 40.5 wt% and the specific gravity was more than 1.470 g/cm ³ It was confirmed that mechanical properties, extrudability, etc. were lowered.

Although the above has been described with reference to the preferred embodiment of the present invention, those skilled in the art can variously modify and change the present invention within the scope without departing from the spirit and scope of the present invention described in the claims described below. You can do it. Therefore, if the modified implementation basically includes the elements of the claims of the present invention, all should be considered to be included in the technical scope of the present invention.

100: conductor 200: insulating layer
300: sheath layer 400: metal shielding layer

Claims (16)

A non-crosslinked insulating composition comprising:
a polyolefin resin grafted with polypropylene, an ethylene copolymer and maleic anhydride as a base resin;
contains a flame retardant;
A non-crosslinked insulating composition having a melt flow rate (MFR) of 20 to 26 g/10 min (190° C., 21.6 kg) and a minimum torque (ML) (190° C.) of 1.1 to 1.4 lb-in. According to claim 1,
The non-crosslinked insulating composition, characterized in that the relationship between the melt flow rate (MFR) and the lowest point torque (ML) satisfies Equation 3 below.
[Equation 3]

3. The method of claim 1 or 2,
In the case of differential scanning calorimetry (DSC) of the non-crosslinked insulating composition, at least one peak at 150 to 170 ° C, and at least one peak at 70 to 100 ° C. bridge insulation composition. 4. The method of claim 3,
The polypropylene resin comprises a propylene block copolymer having a melting point of 150 to 170 °C,
The ethylene copolymer includes two types of polyolefin elastomers (POE) having a melting point of 60 to 100° C. and different melting points from each other,
The non-crosslinked insulating composition, characterized in that the polyolefin resin grafted with maleic anhydride comprises a polyolefin elastomer grafted with maleic anhydride having a melting point of 70 to 90°C. 5. The method of claim 4,
The polypropylene resin is a non-crosslinked insulating composition comprising a propylene block copolymer polymerized in the presence of a metallocene catalyst. 5. The method of claim 4,
The ethylene copolymer comprises a low melting point polyolefin elastomer (POE) having a melting point of 60 to 70 °C and a high melting point polyolefin elastomer (POE) having a melting point of 75 to 100 °C, a non-crosslinked insulating composition. 3. The method of claim 1 or 2,
Based on 100 parts by weight of the base resin, the content of the polypropylene resin is 20 to 40 parts by weight, the content of the ethylene copolymer is 40 to 65 parts by weight, and the maleic anhydride is grafted (grafted) polyolefin resin The non-crosslinked insulating composition, characterized in that the content is 10 to 20 parts by weight. 7. The method of claim 6,
The non-crosslinked insulated cable, characterized in that the high melting point polyolefin elastomer (POE) and the low melting point polyolefin elastomer (POE) satisfy Equations 1 and 2 below.
[Equation 1]

[Equation 2]

In Equations 1 and 2 above,
x ₁ , MI ₁ and Tm ₁ are the content (g), melt index (g/10min) and melting point (°C) of the high melting point polyolefin elastomer, respectively,
x ₂ , MI ₂ and Tm ₂ are the content (g), melt index (g/10min) and melting point (°C) of the low melting point polyolefin elastomer, respectively. 3. The method of claim 1 or 2,
The flame retardant is a non-crosslinked insulating composition, characterized in that it comprises a metal hydroxide flame retardant and a nitrogen-based flame retardant auxiliary agent. 10. The method of claim 9,
The nitrogen-based flame retardant auxiliary agent, characterized in that it comprises melamine cyanurate, non-crosslinked insulation composition. 10. The method of claim 9,
In the case of thermogravimetric analysis (TGA) of the insulating composition, the content of ash is 38.5 to 40.5 wt% based on the total weight of the insulating composition,
The non-crosslinked insulating composition, characterized in that the specific gravity of the insulating composition is 1.457 to 1.470 g/cm ³ . 12. The method of claim 11,
Based on 100 parts by weight of the base resin, the content of the metal hydroxide flame retardant is 150 to 190 parts by weight,
Based on the total weight of the non-crosslinked insulating composition, the content of the nitrogen-based flame retardant aid is 5 to 20 parts by weight of the non-crosslinked insulating composition. 3. The method of claim 1 or 2,
Based on 100 parts by weight of the base resin, calcium carbonate (CaCO ₃ ) 1 to 20 parts by weight as a filler, the non-crosslinked insulating composition comprising. 14. The method of claim 13,
Based on 100 parts by weight of the base resin, the total content of the flame retardant and the filler is 150 to 200 parts by weight, the non-crosslinked insulating composition. 3. The method of claim 1 or 2,
Based on 100 parts by weight of the base resin, 0.5 to 5 parts by weight of a lubricant and 0.1 to 10 parts by weight of other additives are included,
The other additives are non-crosslinked insulation composition, characterized in that it comprises at least one selected from the group consisting of antioxidants, moisture absorbents, processing stabilizers and pigments. conductor; and
A non-crosslinked insulated wire surrounding the conductor and comprising an insulating layer formed from the insulating composition of claim 1 or 2.

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