High heat resistance and flame retardant composition for outdoor cable sheathing, and composites prepared thereby

Abstract

The present invention relates to a flame-retardant polymer composite composition that can be used as a cable sheathing material, and more specifically, to a high-heat-resistant and flame-retardant composition for outdoor cable sheathing having a novel composition of organic and inorganic materials suitable for outdoor use, which exhibits superior flame retardancy and heat resistance despite containing a lower content of a component acting as a flame retardant than in the prior art, and also has improved mechanical properties as well as UV stability, and to a polymer composite resin manufactured from said composition.

Description

Technology Field

[0001] The present invention relates to a flame-retardant polymer composite composition that can be used as a cable sheathing material, and more specifically, to a high-heat-resistant and flame-retardant composition for outdoor cable sheathing having a novel composition of organic and inorganic materials suitable for outdoor use, which exhibits superior flame retardancy and heat resistance despite containing a lower content of a component acting as a flame retardant than in the prior art, and also has improved mechanical properties as well as UV stability, and to a polymer composite resin manufactured from said composition. Background Technology

[0002] Generally, the structure of a cable consists of a conductor, an insulator, and a sheath, and cross-linked polyethylene (XLPE), polyethylene (PE), and polyvinyl polyethylene (PVC) are commonly used as insulators. Methods for making these cables flame-retardant are broadly divided into methods that use a metal sheath such as lead sheathing or incorporate non-combustible materials such as glass fiber braiding, and methods that make the sheath material, insulation, and other constituent materials of general cables flame-retardant. Among these, cables with a metal sheath and outer covering are used only when chemical resistance is required or for direct burial installation due to handling issues and economic considerations. To make cables flame-retardant economically or effectively without changing the structure or handling methods of generally used cables, a method of adding flame retardants such as halogen-based, phosphorus-based, or inorganic flame retardants to the cable sheath material is being used.

[0003] In particular, as toxicity issues have arisen, flame-retardant compositions incorporating polyolefins and metal hydroxides such as magnesium hydroxide and aluminum hydroxide have recently been developed to replace commonly used polyvinyl chloride and halogen flame retardants. However, in order for these compositions to exhibit flame-retardant performance, an excessive amount of metal hydroxides must be added, which leads to a problem where other properties, such as the flexibility and mechanical properties of the wire, are degraded. In other words, while flame retardancy improves as the amount of filler material, such as flame retardants, conversely, various problems arise, such as a decrease in other cable properties, namely mechanical strength, and an increase in density that increases the weight of the cable.

[0004] Furthermore, when cables are used outdoors rather than indoors, they are exposed to sunlight, rain, and wind for extended periods; therefore, they require higher resistance to external environmental factors such as ultraviolet rays, heat, and humidity compared to when used indoors.

[0005] Therefore, there is a need to develop a resin composition for outdoor cable sheathing that has excellent flame retardancy while minimizing the amount of added flame retardant, and possesses UV resistance and weather resistance suitable for outdoor use, such as solar cables. Prior art literature

[0006] Republic of Korea Registered Patent Publication No. 10-0556318 The problem to be solved

[0007] Accordingly, the objective of the present invention is to provide a high heat-resistant and high flame-retardant polymer composite composition for outdoor cable sheathing that includes a combination of components and a UV-blocking component, which not only offers excellent economic and eco-friendliness by using industrial by-products generated in the paper or steel industry and metal hydroxides as the main flame retardants, but also possesses superior flame-retardant performance while using a lower total content of components acting as flame retardants compared to conventional technology.

[0008] Another objective of the present invention is to provide a flame-retardant polymer composite resin suitable for outdoor cables, particularly solar cables used in photovoltaic power generation systems, and an outdoor cable coated with said resin layer, which is composed of said polymer composite composition for cable sheathing, has high melt flow index, elongation, and heat resistance, has low hardness and is flexible, thus having excellent processability, has flame retardancy greater than the IEC 60332-3 standard, satisfies the IEC 62930 weather resistance standard, and has mechanical properties, particularly tensile strength, satisfies the UL 3817 standard.

[0009] The objectives of the present invention are not limited to those mentioned above, and may naturally include objectives of the invention that a person skilled in the art can recognize from the description in the detailed description of the invention that follows, even if not explicitly mentioned. means of solving the problem

[0010] To achieve the objectives of the present invention described above, the present invention provides a high heat-resistant and high flame-retardant polymer composite composition for outdoor cable sheathing comprising: 30% to 55% by weight of a polyolefin-based resin composition; 20% to 45% by weight of one or more industrial by-products selected from the group consisting of Paper Sludge Ash, Blast Furnace Slag, Converter Slag, and combinations thereof; 1% to 20% by weight of a metal hydroxide; 1% to 4% by weight of a crosslinking aid; and 0.1% to 5% by weight of a Hindered Amine Light Stabilizer (HALS).

[0011] In a preferred embodiment, the industrial byproduct and the metal hydroxide act as flame retardants, and may further include 1% to 20% by weight of one or more of calcium-based flame retardants, phosphorus-based flame retardants, and nitrogen-based flame retardants, and the total content of all components acting as flame retardants is 55% by weight or less.

[0012] In a preferred embodiment, the calcium-based flame retardant has a moisture content of 10 parts by weight or less.

[0013] In a preferred embodiment, the polyolefin resin composition comprises a polar polyolefin resin and a polyolefin resin in a weight ratio of 1:9 to 5:5.

[0014] In a preferred embodiment, the polar polyolefin resin has a structure in which a polar monomer is grafted onto a polyolefin resin, and the polar monomer is included in an amount of 0.1 to 5 parts by weight per 100 parts by weight of the total weight.

[0015] In a preferred embodiment, the polar monomer is one or more selected from the group consisting of maleic anhydride, acrylic acid, glyceryl methacrylate, and combinations thereof.

[0016] In a preferred embodiment, the polyolefin resin is any one selected from the group consisting of polyethylene, polypropylene, polyethylene / α-olefin, ethylene-α-olefin copolymer, ethylene-vinyl acetate copolymer, ethylene-propylene-diene copolymer, and combinations thereof.

[0017] In a preferred embodiment, the polar polyolefin resin has a weight-average molecular weight of 50,000 g / mol to 500,000 g / mol, a melt flow index of 1 g / 10 min to 10 g / 10 min, and a Shore hardness (Shore A) of 90 or less.

[0018] In a preferred embodiment, the metal hydroxide is selected from the group consisting of aluminum hydroxide, magnesium hydroxide, calcium hydroxide, sodium hydroxide, and combinations thereof.

[0019] In a preferred embodiment, the calcium-based flame retardant is one or more selected from the group consisting of calcium carbonate, calcium oxide, calcium sulfate, and combinations thereof.

[0020] In a preferred embodiment, the phosphorus-based flame retardant is any one selected from the group consisting of ammonium polyphosphate, red phosphorus, melamine polyphosphate, aluminum diethyl phosphinate, piperazine pyrophosphate, and combinations thereof.

[0021] In a preferred embodiment, the crosslinking aid is any one selected from the group consisting of triaryl cyanurate, triaryl isocyanurate, trimethylolpropane trimethacrylate, and combinations thereof.

[0022] In a preferred embodiment, one or more of a styrene-based block copolymer, an organosilane, an antioxidant, a lubricant, and a coloring agent are further included, wherein the styrene-based block copolymer is included in an amount of 1% to 15% by weight, the organosilane is included in an amount of 0.1% to 3% by weight, the antioxidant is included in an amount of 0.1% to 5% by weight, the lubricant is included in an amount of 0.1% to 5% by weight, and the coloring agent is included in an amount of 0.1% to 3% by weight.

[0023] In a preferred embodiment, the styrene-based block copolymer is any one selected from the group consisting of styrene-ethylene-butadiene-styrene copolymer, styrene-butadiene-styrene copolymer, and combinations thereof; the organosilane is any one selected from the group consisting of vinyltrimethoxysilane, vinyltriethoxysilane, vinyltributoxysilane, propyltrimethoxysilane, propyltriethoxysilane, and combinations thereof; the lubricant is any one selected from the group consisting of paraffin, polyethylene wax, alkaline earth metal stearate, vinylidene fluoride-hexafluoropropylene copolymer, polyester polyol, erucamide, oleic amide, and combinations thereof; and the coloring agent is any one selected from the group consisting of carbon black, titanium dioxide, pigment, and combinations thereof.

[0024] In addition, the present invention provides a high heat-resistant and flame-retardant polymer composite resin for outdoor cable sheathing, characterized by being formed from any one of the high heat-resistant and flame-retardant polymer composite compositions for outdoor cable sheathing described above.

[0025] In a preferred embodiment, it has flame retardancy greater than the IEC 60332-3 standard and heat resistance at an operating temperature of 125°C or higher, and satisfies the IEC 62930 weather resistance standard.

[0026] In addition, the present invention provides a flame-retardant polymer composite resin for outdoor cable sheathing, characterized by being formed from the above-described high-heat-resistant and high-flame-retardant polymer composite composition for outdoor cable sheathing, having flame retardancy greater than the IEC 60332-3 standard and heat resistance of 125°C or higher for use, and satisfying the IEC 62930 weather resistance standard.

[0027] In addition, the present invention provides an outdoor flame-retardant cable comprising one or more insulating coating layers formed of the polymer composite resin described above. Effects of the invention

[0028] The high heat-resistant and high flame-retardant polymer composite composition for outdoor cable sheathing according to the present invention described above is suitable for outdoor cable sheathing as it utilizes industrial by-products generated in the paper or steel industry and metal hydroxides as the main flame retardants, thereby offering excellent economic and eco-friendliness, and also includes a combination of components and UV blocking components that provide superior flame-retardant performance while using a lower total content of components acting as flame retardants compared to conventional technology.

[0029] In addition, the flame-retardant polymer composite resin of the present invention has high melt flow index, elongation, and heat resistance, and is flexible due to its low hardness, so it has excellent processability, has flame retardancy greater than the IEC 60332-3 standard, satisfies the IEC 62930 weather resistance standard, and its mechanical properties, particularly tensile strength, satisfy the UL 3817 standard, so the cable coated with the resin layer can be used outdoors for a long period without changes in properties, making it suitable as an outdoor cable, especially as a solar cable used in a photovoltaic power generation system.

[0030] These technical effects of the present invention are not limited to the scope mentioned above, and naturally include effects of the invention that a person skilled in the art can recognize from the description of specific details for implementing the invention that follows, even if not explicitly mentioned. Brief explanation of the drawing

[0031] Figure 1 is a graph showing the results of a component analysis of paper sludge ash, an industrial byproduct used in the present invention. Figure 2a is a photograph of a surface that passed the heat resistance evaluation, and Figure 2b is a photograph of a surface that failed the heat resistance evaluation. Specific details for implementing the invention

[0032] The terms used in this invention are used merely to describe specific embodiments and are not intended to limit the invention. The singular expression includes the plural expression unless the context clearly indicates otherwise. In this application, terms such as "comprising" or "having" are intended to specify the presence of the features, numbers, steps, actions, components, parts, or combinations thereof described in the description of the invention, and should be understood as not precluding the existence or addition of one or more other features, numbers, steps, actions, components, parts, or combinations thereof.

[0033] Terms such as "first," "second," etc., may be used to describe various components, but said components should not be limited by said terms. These terms are used solely for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, the first component may be named the second component, and similarly, the second component may be named the first component.

[0034] Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as generally understood by those skilled in the art to which this invention pertains. Terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the relevant technology, and should not be interpreted in an ideal or overly formal sense unless explicitly defined in this invention.

[0035] In interpreting the components, they shall be interpreted as including a margin of error even without separate explicit indication. In particular, when terms of degree such as "approximately" or "substantially" are used, they may be interpreted as being used in the sense of being at or near the numerical value where inherent manufacturing and material tolerances are presented in the stated meaning. Furthermore, where a numerical range is disclosed in the description, such range is continuous and, unless otherwise indicated, includes all values ​​from the minimum value of such range up to the maximum value. Moreover, where such range refers to an integer, it includes all integers from the minimum value up to the maximum value, unless otherwise indicated.

[0036] In the case of an explanation of a temporal relationship, for example, when the temporal sequence is explained using 'after', 'following', 'next', 'before', etc., it includes cases where the sequence is not continuous unless 'immediately' or 'directly' is used.

[0037] Hereinafter, the technical configuration of the present invention will be described in detail with reference to the attached drawings and preferred embodiments.

[0038] However, the present invention is not limited to the embodiments described herein, and in other forms, the same reference numerals indicate the same components.

[0039] The technical feature of the present invention is a flame-retardant polymer composite composition for outdoor cables that has excellent economic and eco-friendliness by using industrial by-products generated in the paper or steel industry and metal hydroxides as the main flame retardants, and also has excellent flame retardant and heat resistance through a combination of components that have superior flame retardant performance while using a lower total content of components acting as flame retardants compared to conventional technology, and a special combination of various organic and inorganic materials including UV blocking components, and has excellent flexibility and extrusion processability due to low hardness, satisfies the IEC 62930 weathering standard, and even satisfies the UL 3817 standard for mechanical properties, particularly tensile strength, making it suitable as a sheathing material for outdoor cables, especially solar cables.

[0040] Accordingly, the high heat-resistant and high flame-retardant polymer composite composition for outdoor cable sheathing according to the present invention comprises 30% to 55% by weight of a polyolefin-based resin composition; 20% to 45% by weight of one or more industrial by-products selected from the group consisting of Paper Sludge Ash, Blast Furnace Slag, Converter Slag, and combinations thereof; 1% to 20% by weight of a metal hydroxide; 1% to 4% by weight of a crosslinking aid; and 0.1% to 5% by weight of a Hindered Amine Light Stabilizer (HALS). If necessary, it may further comprise one or more of a calcium-based flame retardant, a phosphorus-based flame retardant, and a nitrogen-based flame retardant, and / or further comprise one or more of a styrene-based block copolymer, an organosilane, an antioxidant, a lubricant, and a colorant.

[0041] Here, industrial by-products are one or more selected from the group consisting of paper sludge ash, which is generated in large quantities in the papermaking process but is not yet recycled, or blast furnace slag, converter slag, and combinations thereof generated in iron and steelmaking processes, and mainly include metal oxides. Paper sludge ash is a material obtained by performing incineration heat treatment on paper sludge. The paper sludge particles do not separate from each other but form aggregates, and as shown in Fig. 1, Ca, Si, Al, Mg, Na, etc. mainly exist in oxide form. Blast furnace slag refers to a product generated during the process of manufacturing pig iron in a blast furnace at a steel mill. It is produced when SiO2 and AlO3, etc. present in the ash of the main raw material (iron ore) and auxiliary raw material (coke, limestone), react with lime at high temperatures. It exhibits mineralogical characteristics similar to Melilite {(Ca, Na)₂[SiO₄]} and Merwinite [Ca₃Mg(SiO₄)₂]. Converter slag is a product generated during the process of refining pig iron in a converter to remove impurities such as carbon, phosphorus, and sulfur, and consists of Belite, Calcium Ferrite, Westite, freeCaO, etc.

[0042] As such, the industrial by-products used in this invention mainly contain metal oxides, and it has been confirmed through this invention that when used in combination with metal hydroxides, mechanical properties and flame retardancy are improved and productivity is increased.

[0043] In other words, this is because the following problems existed when using metal hydroxides alone as non-halogenated flame retardants, as in conventional technology. First, due to poor compatibility with polymers, aggregation occurs during mixing using rolls or closed mixers, which can lead to a decrease in mechanical properties such as tensile strength and elongation. Additionally, productivity may be reduced as the maximum additive amount (linked to flame retardancy), production equipment, and process temperature are limited due to production facility load and productivity. In the case of general high-flame retardant products containing metal hydroxides, the high flame retardant content (over 60 wt%) limits production speed in batch processes using kneader extruders. Furthermore, as the metal hydroxides decompose due to the heat applied during the extrusion process, releasing water, problems such as a rough appearance and porosity were encountered, which restricted the upward adjustment of the process temperature (linked to production volume).

[0044] However, when industrial by-products containing metal hydroxides and metal oxides are used in parallel as in the present invention, the problem of water release caused by the decomposition of metal hydroxides due to heat applied during the extrusion process can be improved by the industrial by-products, which are highly stable to heat; thus, it is possible to increase production volume by raising the process temperature. As shown in the reaction equation below, since the metal oxides contained in the industrial by-products can be converted into complex metal compounds such as metal hydroxides as time passes while the product is exposed to air and moisture during the extrusion process (e.g., passing through a water bath) and thereafter, it does not affect the flame-retardant performance, which is the primary purpose of metal hydroxides.

[0045]

[0046] In addition, the combination of metal hydroxides and metal oxides contained in industrial by-products allows for the addition of a larger molar amount of Char Materials compared to metal hydroxides alone based on the same content, thus offering the advantage of securing high flame retardancy with a smaller amount.

[0047] If the content of industrial by-products is less than 20 weight%, there is a problem that the flame retardant performance is insufficient to satisfy the vertical tray flame retardant test standard, and if it exceeds 45 weight%, there may be problems such as a load on processing equipment such as twin-screw extruders and a decrease in physical properties due to poor dispersion.

[0048] Metal hydroxides are components for improving the flame retardancy of polymer composite compositions. They are not limited to known metal hydroxides, but as one embodiment, they may be any one selected from the group consisting of aluminum hydroxide, magnesium hydroxide, calcium hydroxide, sodium hydroxide, and combinations thereof. If the content of the metal hydroxide is less than 1 weight%, problems such as reduced heat resistance and UV stability may occur due to antagonism with some secondary antioxidants, such as HALS and thioether-based antioxidants. If it exceeds 20 weight%, it decomposes due to heat applied during the process and releases water, which may cause problems such as poor appearance and reduced productivity.

[0049] As described above, industrial by-products and metal hydroxides act as flame retardants, and if necessary, one or more of calcium-based flame retardants, phosphorus-based flame retardants, and nitrogen-based flame retardants may be additionally included in an amount of 1% to 20% by weight. Even when additional flame retardants are included in this manner, the total content of all components acting as flame retardants, namely industrial by-products, metal hydroxides, and added flame retardants, may be 55% by weight or less. The high heat-resistant and high flame-retardant polymer composite composition for outdoor cable sheathing according to the present invention exhibited excellent flame-retardant properties that satisfy a very high flame-retardant grade exceeding the IEC 60332-3 standard, as described below, even when all components acting as flame retardants were included in an amount of 55% by weight or less.

[0050] Calcium-based flame retardants are not limited to being calcium-based compounds having flame retardancy, but as one embodiment, they may be one or more selected from the group consisting of calcium carbonate, calcium oxide, calcium sulfate, and combinations thereof. If necessary, the surface of the calcium-based flame retardant may be modified to increase compatibility with other compounds; as one embodiment, the calcium-based flame retardant may be modified so that its surface is coated with silane or stearic acid. The calcium-based flame retardant used in the present invention may have a moisture content of 10 parts by weight or less and an average particle size of 1 to 20 μm, and the average particle size may be measured using a commercially available laser diffraction scattering particle size distribution meter, for example, a MicroTrack particle size distribution meter. Alternatively, 200 particles may be randomly extracted from an electron microscope image and the average particle diameter may be calculated.

[0051] Phosphorus-based flame retardants and nitrogen-based flame retardants are non-halogenated flame retardants, and nitrogen-based flame retardants may include melamine resin, melamine cyanurate, etc., while phosphorus-based flame retardants may be one or more selected from the group consisting of ammonium polyphosphate, red phosphorus, melamine polyphosphate, aluminum diethyl phosphinate, piperazine pyrophosphate, and combinations thereof. The flame retardants may be surface-treated with silane-based or titanate-based coupling agents, and the surface-treated flame retardants may improve dispersibility within the polymer composite resin.

[0052] Calcium-based flame retardants, phosphorus-based flame retardants, and nitrogen-based flame retardants having these characteristics may be included in the high heat-resistant and flame-retardant polymer composite composition for cable sheathing of the present invention in an amount of 1 to 20 weight%, either individually or in combination of one or more. If the amount is less than 1 weight%, the flame retardancy of the flame-retardant polymer composite composition is insufficient, and if it exceeds 20 weight%, problems such as reduced moldability, elasticity, and extrudability may occur.

[0053] The polyolefin resin composition is not limited to being composed of a polar polyolefin resin and a polyolefin resin, but as one embodiment, the polar polyolefin resin and the polyolefin resin may be included in a weight ratio of 1:9 to 7:3. This is because if the ratio is less than 1:9, problems such as poor compatibility with high content of metal hydroxides and industrial by-products and reduced flame retardant performance may occur, and if the ratio exceeds 7:3, problems such as adhesion inside the extruder due to high polarity and reduced processability and productivity due to increased crosslinking density may occur.

[0054] Polar polyolefin resins are modified resins prepared by introducing polar functional groups into polyolefin resins. In one embodiment, they may have a structure in which polar monomers are grafted onto a polyolefin resin. They can be obtained by grafting a polar monomer containing a polar functional group onto a polyolefin resin through reaction extrusion. A reaction initiator may be added to the grafting reaction to obtain such polar polyolefin resins, and the reaction initiator may be an organic peroxide, etc.

[0055] Consequently, the polar polyolefin resin may comprise a polyolefin resin as the main chain, a polar monomer grafted onto the main chain, and a polar functional group contained in the polar monomer, wherein the polar monomer may be one or more selected from the group consisting of maleic anhydride, acrylic acid, glyceryl methacrylate, and combinations thereof, and the polyolefin resin may be one or more selected from the group consisting of polyethylene, polypropylene, polyethylene / α-olefin, ethylene-α-olefin copolymer, ethylene-vinyl acetate copolymer, ethylene-propylene-diene copolymer, and combinations thereof.

[0056] The graft amount of polar monomer included in the polar polyolefin resin is not particularly limited, but as one embodiment, it may be 0.1 to 5 parts by weight based on 100 parts by weight of the polar polyolefin resin. This is because if it is less than 0.1 parts by weight, the modification effect of the polyolefin resin may not be significant, and if it exceeds 5 parts by weight, disadvantages such as reduced processability and yellowing may occur.

[0057] As one embodiment, the polar polyolefin resin included in the high heat-resistant and flame-retardant polymer composite composition for outdoor cable sheathing of the present invention may have a weight-average molecular weight of 50,000 g / mol to 500,000 g / mol, a melt flow index of 1 g / 10 min to 10 g / 10 min (230°C, 2.16 Kgf), and a Shore hardness (Shore A) of 95 or less. The lower limit of the Shore hardness is not particularly limited, but may be, for example, 50 or more, or 60 or more. If each physical property of the polar polyolefin resin deviates from the above numerical range, the physical properties such as melt flow index, Shore hardness (Shore A), tensile strength, and elongation of the high heat-resistant and flame-retardant polymer composite composition for solar cable sheathing of the present invention obtained finally may deviate from the required values.

[0058] The polyolefin resin included in the polyolefin resin composition may be any known olefin resin, and as one embodiment, it may be any one selected from the group consisting of polyethylene, polypropylene, polyethylene / α-olefin, ethylene-α-olefin copolymer, ethylene-vinyl acetate copolymer, ethylene-propylene-diene copolymer, and combinations thereof.

[0059] A polyolefin-based resin composition having these characteristics may be included in the high heat-resistant and high flame-retardant polymer composite composition for outdoor cable sheathing of the present invention in an amount of 30 to 55 weight percent. This is because if the content of the polyolefin-based resin composition is less than 30 weight percent, the extrusion appearance and processability may be reduced, and if it exceeds 55 weight percent, the flame retardancy of the polymer composite resin may be reduced.

[0060] The crosslinking aid is a component for improving crosslinking properties and enhancing heat and oil resistance properties during the manufacture of the polymer composite resin of the present invention, and any crosslinking aid that is typically usable in polyolefin-based resins can be used. In one embodiment, it may be one or more selected from the group consisting of triaryl cyanurate, triaryl isocyanurate, trimethylolpropane trimethacrylate, and combinations thereof.

[0061] A crosslinking agent may be included in the high heat-resistant and flame-retardant polymer composite composition for cable sheathing of the present invention in an amount of 1 to 4 weight percent. If the content of the crosslinking agent is less than 1 weight percent, the crosslinking efficiency of the composition is lowered, and physical properties, heat resistance, etc. are reduced. If it exceeds 4 weight percent, quality defects such as leaching out of the resin and a decrease in heat resistance due to unreacted crosslinking agent may occur.

[0062] Hindered Amine Light Stabilizer (HALS) acts as a UV stabilizer that stabilizes polymers by converting ultraviolet rays into heat. While not limited to hindered amine-based compounds, as one embodiment, poly[[6-[(1,1,3,3-tetramethylbutyl)amino]-1,3,5-triazine-2,4-dyl][(2,2,6,6-tetramethyl-4-pipyridinyl)amino]-1,6-hesanidyl[(2,2,6,6-tetramethyl-4-pipyridinyl)imimino]] may be used. HALS may be included in an amount of 0.1% to 5% by weight, and within this content range, weather resistance necessary to ensure reliability during long-term use can be provided. This is because if the HALS content is less than 0.1% by weight, a problem of insufficient UV stability occurs, and if it exceeds 5% by weight, problems such as deterioration of physical properties and surface whitening occur.

[0063] As an antioxidant is a component for improving oxidation prevention and heat resistance properties, any known antioxidant may be used, but as one embodiment, it may be selected from the group consisting of phenolic primary antioxidants, phosphorus-based secondary antioxidants, sulfur-based secondary antioxidants, and combinations thereof.

[0064] The phenolic primary antioxidant may be any one selected from the group consisting of pentaerythrityl tetrakis(3-(3,5-di-tert-butyl-4-hydroxyphenyl)-propionate), 2,3-bis[[3-[3,5-di-tert-butyl-4-hydroxyphenyl]propionyl]]propionohydrazide, 2,2'-thiodiethylbis-[3-(3,5-di-tert-butyl-4-hydroxyphenyl)-propionate] and combinations thereof, the phosphorus-based secondary antioxidant may include tris(2,4-di-tert-butylphenyl)phosphite, and the sulfur-based secondary antioxidant may include thio compounds such as dilauryl thiopropionate, didodecyl thiodipropionate, distearyl thiodipropionate, and dimyristyl thiodipropionate.

[0065] An antioxidant having these characteristics may be included in the high heat-resistant and flame-retardant polymer composite composition for cable sheathing of the present invention in an amount of 0.1 to 5 weight percent. Within this range, it prevents oxidation of the polymer by heat, thereby ensuring resistance to heat, and can contribute to improved weather resistance by exhibiting a synergistic effect with a UV stabilizer. That is, if the amount is less than 0.1 weight percent, the effect of improving oxidation prevention and heat resistance cannot be expected, and if it exceeds 5 weight percent, a whitening problem caused by precipitation on the wire surface may occur.

[0066] Meanwhile, the industry has known about the limitation that UV stabilizers such as HALS and thioether-based antioxidants cannot be used in combination, because an antagonistic reaction occurs where the two additives react rather than react with external environments (UV, temperature, etc.), resulting in performance degradation. The effect of this antagonistic reaction was accelerated as acidification increased due to the reaction caused by sulfuric acid generated by the decomposition of thioether-based antioxidants. However, the polymer composite composition of the present invention is composed of metal hydroxides with basic properties and industrial by-products containing metal oxides (which convert into metal hydroxides over time), and since it can neutralize acidification caused by thioether-based antioxidants, it exhibited the effect of suppressing the antagonistic reaction between the two additives even when HALS and thioether-based antioxidants are used in combination.

[0067] As a result, the polymer composite composition of the present invention can secure not only excellent UV stability but also long-term high heat resistance by using HALS as a UV stabilizer when necessary, while simultaneously using a thioether-based antioxidant with excellent long-term heat resistance as an antioxidant.

[0068] Styrene-based block copolymers can be included as insulating materials as a type of rubber component, and may be any one selected from the group consisting of styrene-ethylene-butadiene-styrene copolymers, styrene-butadiene-styrene copolymers, and combinations thereof.

[0069] In one embodiment, the styrene-ethylene-butadiene-styrene copolymer may be formed with a styrene content of 10% to 40% by weight, and in one embodiment, the styrene-butadiene-styrene copolymer may be formed with a styrene content of 20% to 50% by weight.

[0070] In addition, as one embodiment, the styrene-ethylene-butadiene-styrene copolymer may have a melt flow index of 0.1 g / 10 min to 10 g / 10 min (190°C, 2.16 kg, 10 min) and a Shore hardness (Shore A) of 90 or less. As one embodiment, the styrene-butadiene-styrene copolymer may have a melt flow index of 0.1 g / 10 min to 10 g / 10 min (190°C, 2.16 kg, 10 min) and a Shore hardness (Shore A) of 50 to 80.

[0071] A styrene-based block copolymer having these characteristics may be included in the high heat-resistant and high flame-retardant polymer composite composition for outdoor cable sheathing of the present invention in an amount of 1% to 15% by weight. If the amount is less than 1% by weight, the effect of improving crosslinking efficiency is negligible and the hardness increases, causing problems with flexibility. If the amount exceeds 15% by weight, not only is there a problem with lowering tensile strength, but it also inhibits the condensation reaction of polar polyolefin resins, causing problems with heat resistance and flame retardancy.

[0072] Organosilanes may be organic compounds formed by introducing basic functional groups into high heat-resistant and high flame-retardant polymer composite compositions for outdoor cable sheathing, wherein a hydrogen atom, a hydroxyl group (-OH), an alkyl group having 1 to 10 carbon atoms, an alkoxy group having 2 to 10 carbon atoms, and an alkenyl group having 2 to 10 carbon atoms containing one or more double bonds are bonded to a silicon atom (Si).

[0073] Therefore, organosilanes undergo a condensation reaction with maleic acid of polar olefin resins, and since water is produced during this process, high flame retardancy with an oxygen index of 40% or higher can be achieved.

[0074] As one embodiment, the organosilane is not limited to having at least one functional group selected from hydroxyl groups and alkoxy groups, but may be one or more selected from the group consisting of vinyltrimethoxysilane, vinyltriethoxysilane, vinyltributoxysilane, propyltrimethoxysilane, propyltriethoxysilane, and combinations thereof.

[0075] Organosilanes having these characteristics may be included in the high heat-resistant and high flame-retardant polymer composite composition for outdoor cable sheathing of the present invention in an amount of 0.1 to 3 weight percent, because if it is less than 0.1 weight percent, the flame retardancy of the flame-retardant polymer composite composition may not be improved due to a decrease in acid-base reaction, and if it exceeds 3 weight percent, extrusion processability may be reduced due to a decrease in melt flow index.

[0076] As a component for improving processability, any lubricant commonly used in the field may be used, but as one embodiment, it may be any one selected from the group consisting of low molecular weight paraffin, polyethylene wax, alkaline earth metal stearate salt, vinylidene fluoride-hexafluoropropylene polymer, polyester polyol, erucamide, oleic amide, and combinations thereof, with a weight-average molecular weight in the range of 100 to 1,000.

[0077] A lubricant having the characteristics described above may be included in the high heat-resistant and high flame-retardant polymer composite composition for outdoor cable sheathing of the present invention in an amount of 0.1 to 5 weight percent, because if it is less than 0.1 weight percent, the effect of improving processability cannot be expected, and if it exceeds 5 weight percent, a decrease in dispersion of the mixture and appearance defects caused by the generation of low molecular weight gas may occur.

[0078] The coloring agent is a component that imparts color to the high heat-resistant and high flame-retardant polymer composite composition for outdoor cable sheathing according to the present invention, and may further include a conventional coloring agent. In one embodiment, the coloring agent may be selected from the group consisting of carbon black, titanium dioxide, pigments, and combinations thereof. In addition, it may be included in the high heat-resistant and high flame-retardant polymer composite composition for outdoor cable sheathing according to the present invention in an amount of 0.1 to 3 weight percent. This is because if the amount is less than 0.1 weight percent, the desired color cannot be achieved, and if it exceeds 3 weight percent, problems may arise that reduce the melt flow index, tensile strength, and elongation.

[0079] Next, the polymer composite resin for outdoor cable sheathing according to the present invention may be formed from a high-heat-resistant and high-flame-retardant polymer composite composition for outdoor cable sheathing comprising the components described above. In order to obtain the polymer composite resin for outdoor cable sheathing from the high-heat-resistant and high-flame-retardant polymer composite composition for outdoor cable sheathing according to the present invention, any known method for making resin may be used. As one embodiment, the polymer composite resin may be obtained by melting and processing a mixed raw material containing the high-heat-resistant and high-flame-retardant polymer composite composition for outdoor cable sheathing by feeding it into a twin-screw extruder, kneader, Banbery mixer, etc.

[0080] The polymer composite resin for outdoor cable sheathing according to the present invention has high flame retardancy that meets or exceeds the IEC 60332-3 standard, which requires higher flame retardancy than the UL 1581 VW-1 standard, and not only has heat resistance at an operating temperature of 125°C or higher, but also meets the IEC 62930 weather resistance standard and is flexible because its Shore A hardness is relatively low at 75 to 95, making it suitable for use inside equipment in confined spaces, ships, and solar cable sheathing.

[0082] Next, the flame-retardant cable for outdoor use according to the present invention can be manufactured by covering a conductor with an insulating coating layer formed by a polymer composite resin having the composition described above. Specifically, it can be manufactured by forming an insulating coating layer with a polymer composite resin produced by melt-processing a high-heat-resistant and high-flame-retardant polymer composite composition for outdoor cable coating onto a conductor such as copper or aluminum, and one or more insulating coating layers formed by the polymer composite resin can be formed. That is, when manufacturing a low-voltage cable, only one layer can be coated using a single-layer extruder, and when manufacturing a high-voltage cable, multiple layers can be coated using a two-layer or three-layer extruder, etc.

[0083] As such, the polymer composite resin of the present invention not only exhibits high flame retardancy and excellent mechanical properties, but also enables stable extrusion processing over a long period of time due to minimal pressure rise within the extruder during the extrusion molding process for manufacturing outdoor cables.

[0084] Examples 1 to 10

[0085] High heat-resistant and high flame-retardant polymer composite compositions 1 to 10 for outdoor cable sheathing were prepared by uniformly mixing the compositional components as shown in Table 1 below in the presented amounts.

[0086]

[0087] Here, the polyolefin resin composition used is one containing polyethylene resin and polar polyethylene / alpha-olefin resin in a weight ratio of 7:3, the polar polyethylene / alpha-olefin resin is a polypropylene block copolymer grafted with 0.5 wt% maleic anhydride, and has a melt flow index of 0.8 g / 10 min.

[0088] The industrial byproduct used was Paper Sludge Ash (incineration ash from domestic company H's paper sludge), a byproduct of the paper industry.

[0089] Magnesium hydroxide was used as the metal hydroxide.

[0090] Calcium carbonate coated with stearic acid (particle size: 1.5㎛) was used as a calcium-based flame retardant.

[0091] Trimethylolpropane trimethacrylate was used as a crosslinking agent.

[0092] HALS used 4-acetoxy-2,2,6,6-tetramethylpiperidine.

[0093] A styrene-ethylene-butadiene-styrene copolymer was used as the styrene-based block copolymer. The styrene-ethylene-butadiene-styrene copolymer used has a melt flow index of 1 g / 10 min and a Shore hardness (Shore A) of 72.

[0094] Propyltrimethoxysilane was used as the organosilane.

[0095] The following antioxidants were used: A: pentaerythrityl tetrakis(3-(3,5-di-tert-butyl-4-hydroxyphenyl)-propionate, B: tris(2,4-di-tert-butylphenyl)phosphite, C: 2',3-bis(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl)propionohydrazide, D: didodecylthiodipropionate.

[0096] A 50 wt% masterbatch of hexafluoropropylene-vinylidene fluoride copolymer (carrier resin: polyethylene) was used as the activator.

[0097] Black color masterbatch (carrier resin: polyethylene) was used as the coloring agent.

[0098] Examples 11 to 20

[0099] High heat-resistant and high flame-retardant polymer composite compositions 1 to 10 for outdoor cable sheathing obtained in Examples 1 to 10 were melted, and polymer composite resins 1 to 10 were manufactured using processing equipment. Here, a 30-pipe twin screw extruder (L / D 40) was used as the processing equipment, and the processing temperature was carried out at 100 to 230°C.

[0100] Comparative Examples 1 to 6

[0101] Comparative example compositions 1 to 6 were prepared by uniformly mixing the compositional components shown in Table 2 below at the presented amounts.

[0102]

[0103] Comparative Examples 7 to 12

[0104] Comparative compositions 1 to 6 obtained in Comparative Examples 1 to 6 were prepared by performing the same method as in Example 11 to produce Comparative composite resins 1 to 6.

[0105] Experimental Example

[0106] Specimens were prepared for polymer composite resins 1 to 10 prepared in Examples 11 to 20 and comparative resins 1 to 6 prepared in Comparative Examples 7 to 12, and physical properties were measured as follows, and the results are shown in Table 3.

[0107] 1. Evaluation of Room Temperature Tensile Strength and Elongation

[0108] Room temperature tensile strength and elongation were evaluated for each specimen obtained in the examples and comparative examples at a speed of 508 mm / min in accordance with IEC 60811-501 standards. The acceptance criteria are a tensile strength of 13.79 MPa or higher and an elongation of 300% or higher.

[0109] 2. Heat resistance evaluation

[0110] In accordance with the KS M 6518 standard, the specimens were heated at 158°C for 168 hours, and the tensile strength and elongation were measured. According to the UL 3817 product standard, the value was evaluated as 100% when it was identical to the initial value, and as passing when it had a change rate of less than 20%. When the heat resistance evaluation result was evaluated as passing, the surface condition was shown as in Fig. 2a, and when evaluated as failing, the surface condition was shown as in Fig. 2b.

[0111] 3. Flame Retardancy Evaluation

[0112] After manufacturing a cable in accordance with the IEC 60332-3 (vertical tray flame retardancy test method) standard, a 3.5m long cable bundle was fixed to a vertical ladder and ignited with a flame from a gas burner at the bottom, and it was evaluated as passing when the flame propagation length was within 2.5m.

[0113] 4. Weather resistance (UV stability)

[0114] In accordance with IEC 62930 standards, specimens were evaluated as acceptable when, after exposure to Xenon-Arc (60 W / m2 ± 15 %, 300 nm and 400 nm) at a temperature of 60 ℃ and a relative humidity of 50% for 720 hours, there were no cracks or discoloration on the specimens and the tensile strength and elongation showed a change rate of less than 30% based on the initial saddle strength and elongation.

[0115] 5. Appearance Evaluation

[0116] Although there is no quantified evaluation method for the internal and external appearance according to the UL 3817 standard, it was evaluated as passing when there were no external defects such as surface protrusions or pores.

[0117]

[0118] From Table 3, it can be seen that polymer composite resins 1 to 10 obtained in Examples 11 to 20 all exhibit flame retardancy satisfying the IEC 60332-3 standard, and although not specifically stated, the Shore A hardness is good at the level of 85 to 91. In the heat resistance test conducted at 158°C, the rate of change is within 10%, significantly satisfying the acceptance criterion of less than 20%, thus possessing heat resistance at an operating temperature of 125°C or higher, and also satisfying all requirements for tensile strength and elongation. In particular, it can be seen that the weather resistance meets the IEC 62930 standard, making them suitable for outdoor use.

[0119] On the other hand, Comparative Resin 1 was manufactured with a composition containing 58% by weight of components acting as flame retardants, with less than the content of polyolefin-based resin and more than the content of industrial by-products, and containing four types of antioxidants; it was found that although it satisfies the standards for flame retardancy, heat resistance, and weather resistance, it lacks marketability due to significantly lower tensile strength and elongation and poor appearance. Comparative Resin 2 was manufactured with a composition containing more than the content of polyolefin-based resin but less than the content of industrial by-products; as it contains more polyolefin-based resin and less industrial by-products than Comparative Resin 1, it was found that although Comparative Resin 2 did not satisfy the flame retardancy compared to Comparative Resin 1, it showed better results in tensile strength and elongation above the acceptance standards, and also passed in heat resistance and appearance. Comparative Resin 3 was manufactured with a composition containing polyolefin resin and industrial by-products within the acceptable range, and metal hydroxides and calcium-based flame retardants below the acceptable range; although it failed to meet the acceptance criteria for flame retardancy and weather resistance, it passed the remaining criteria. Comparative Resins 4, 5, and 6 showed differences in heat resistance and flame retardancy due to the content of crosslinking aids. Comparative Resin 4 failed because the crosslinking aid was excluded, preventing crosslinking of the polyolefin resin and resulting in insufficient tensile strength. Additionally, it failed to meet the flame retardancy standard because flame propagation was not blocked due to a problem where the polymer resin melted and flowed (insufficient char formation) during the flame retardancy test. Conversely, Comparative Saturated 5 had an excessive amount of crosslinking aid added, so an excessive amount of unreacted crosslinking aid remained even after undergoing the e-beam irradiation crosslinking process. The unreacted crosslinking aid continued to crosslink over time due to the heat applied during the heat resistance test, causing the elongation to continuously decrease. Consequently, the rate of change in elongation before and after the heat resistance test exceeded 20%, resulting in failure to meet heat resistance standards. Additionally, it migrated to the surface of the wire, promoting flame propagation during the flame retardancy test, and exceeded the flame propagation range of 2.5m, which is the passing criterion for flame retardancy.Comparative Year 6 did not meet the weather resistance standards because it did not include HALS, but it passed the other standards.

[0120] Although the present invention has been described with reference to preferred embodiments as described above, it is not limited to the aforementioned embodiments, and various changes and modifications may be made by those skilled in the art within the scope of the invention without departing from the spirit of the invention.

Claims

Claim 1 A high heat-resistant and high flame-retardant polymer composite composition for outdoor cable sheathing, comprising 30% to 55% by weight of a polyolefin-based resin composition; 20% to 45% by weight of one or more industrial by-products selected from the group consisting of Paper Sludge Ash, Blast Furnace Slag, Converter Slag, and combinations thereof; 1% to 20% by weight of a metal hydroxide; 1% to 4% by weight of a crosslinking aid; and 0.1% to 5% by weight of a Hindered Amine Light Stabilizer (HALS), wherein the industrial by-product and the metal hydroxide act as flame retardants, and may further include 1% to 20% by weight of one or more of a calcium-based flame retardant, a phosphorus-based flame retardant, and a nitrogen-based flame retardant, wherein the total content of all components acting as flame retardants is 55% by weight or less, and the composition exhibits flame retardancy greater than or equal to the IEC 60332-3 standard due to all components acting as flame retardants. Claim 2 delete Claim 3 A high heat-resistant and high flame-retardant polymer composite composition for outdoor cable sheathing, characterized in that, in claim 1, the calcium-based flame retardant has a moisture content of 10 parts by weight or less. Claim 4 A high heat-resistant and high flame-retardant polymer composite composition for outdoor cable sheathing according to claim 1, characterized in that the polyolefin-based resin composition comprises a polar polyolefin-based resin and a polyolefin-based resin in a weight ratio of 1:9 to 5:

5. Claim 5 A high heat-resistant and high flame-retardant polymer composite composition for outdoor cable sheathing according to claim 4, wherein the polar polyolefin resin has a structure in which a polar monomer is grafted onto a polyolefin resin, and the polar monomer is included in an amount of 0.1 to 5 parts by weight per 100 parts by weight of the total weight. Claim 6 A high heat-resistant and high flame-retardant polymer composite composition for outdoor cable sheathing, characterized in that, in claim 5, the polar monomer is one or more selected from the group consisting of maleic anhydride, acrylic acid, glyceryl methacrylate, and combinations thereof. Claim 7 A high heat-resistant and high flame-retardant polymer composite composition for outdoor cable sheathing according to claim 4, wherein the polyolefin resin is selected from the group consisting of polyethylene, polypropylene, polyethylene / α-olefin, ethylene-α-olefin copolymer, ethylene-vinyl acetate copolymer, ethylene-propylene-diene copolymer, and combinations thereof. Claim 8 A high heat-resistant and high flame-retardant polymer composite composition for outdoor cable sheathing according to claim 4, wherein the polar polyolefin resin has a weight-average molecular weight of 50,000 g / mol to 500,000 g / mol, a melt flow index of 1 g / 10 min to 10 g / 10 min, and a Shore hardness (Shore A) of 90 or less. Claim 9 A high heat-resistant and high flame-retardant polymer composite composition for outdoor cable sheathing, characterized in that, in claim 1, the metal hydroxide is selected from the group consisting of aluminum hydroxide, magnesium hydroxide, calcium hydroxide, sodium hydroxide, and combinations thereof. Claim 10 A high heat-resistant and high flame-retardant polymer composite composition for outdoor cable sheathing, characterized in that, in claim 1, the calcium-based flame retardant is one or more selected from the group consisting of calcium carbonate, calcium oxide, calcium sulfate, and combinations thereof. Claim 11 A high heat-resistant and high flame-retardant polymer composite composition for outdoor cable sheathing according to claim 1, wherein the phosphorus-based flame retardant is selected from the group consisting of ammonium polyphosphate, red phosphorus, melamine polyphosphate, aluminum diethyl phosphinate, piperazine pyrophosphate, and combinations thereof. Claim 12 A high heat-resistant and high flame-retardant polymer composite composition for outdoor cable sheathing, characterized in that, in claim 1, the crosslinking aid is selected from the group consisting of triaryl cyanurate, triaryl isocyanurate, trimethylolpropane trimethacrylate, and combinations thereof. Claim 13 A high heat-resistant and flame-retardant polymer composite composition for cable sheathing according to any one of claims 1, 3 to 12, further comprising one or more of a styrene-based block copolymer, an organosilane, an antioxidant, a lubricant, and a coloring agent, wherein the styrene-based block copolymer is included in an amount of 1% to 15% by weight, the organosilane is included in an amount of 0.1% to 3% by weight, the antioxidant is included in an amount of 0.1% to 5% by weight, the lubricant is included in an amount of 0.1% to 5% by weight, and the coloring agent is included in an amount of 0.1% to 3% by weight. Claim 14 A high heat-resistant and high flame-retardant polymer composite composition for outdoor cable sheathing according to claim 13, wherein the styrene-based block copolymer is any one selected from the group consisting of styrene-ethylene-butadiene-styrene copolymer, styrene-butadiene-styrene copolymer, and combinations thereof; the organosilane is any one selected from the group consisting of vinyltrimethoxysilane, vinyltriethoxysilane, vinyltributoxysilane, propyltrimethoxysilane, propyltriethoxysilane, and combinations thereof; the lubricant is any one selected from the group consisting of paraffin, polyethylene wax, alkaline earth metal stearate, vinylidene fluoride-hexafluoropropylene copolymer, polyester polyol, erucamide, oleic amide, and combinations thereof; and the coloring agent is any one selected from the group consisting of carbon black, titanium dioxide, pigment, and combinations thereof. Claim 15 A high heat-resistant and flame-retardant polymer composite resin for outdoor cable sheathing, characterized by being formed from a high heat-resistant and flame-retardant polymer composite composition for outdoor cable sheathing according to any one of claims 1, 3 to 12. Claim 16 A high-heat-resistant and flame-retardant polymer composite resin for outdoor cable sheathing, characterized in that, in claim 15, it has flame retardancy greater than the IEC 60332-3 standard and heat resistance at an operating temperature of 125°C or higher, and satisfies the IEC 62930 weather resistance standard. Claim 17 A flame-retardant polymer composite resin for outdoor cable sheathing, formed from a high heat-resistant and high flame-retardant polymer composite composition for outdoor cable sheathing according to claim 13, characterized by having flame retardancy greater than the IEC 60332-3 standard and heat resistance at an operating temperature of 125°C or higher, and satisfying the IEC 62930 weather resistance standard. Claim 18 An outdoor flame-retardant cable comprising one or more insulating layers formed of a polymer composite resin of claim 15.

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