Flame-retardant polymer composition

Abstract

This invention relates to a flame-retardant polymer composition, articles such as wires or cables comprising the flame-retardant polymer composition; and the use of the flame-retardant polymer composition in the production of articles such as wires or cables, the flame-retardant polymer composition comprising (A) 2.0 to 15.0 wt% of an ethylene copolymer comprising units selected from the group consisting of methyl acrylate, methyl methacrylate, or mixtures thereof; (B) 0 to 4.0 wt% of polyethylene and / or polypropylene comprising units derived from maleic anhydride; (C) 0.1 to 3.0 wt% of a silicone fluid and / or silicone rubber compound; (D) 40.0 to 55.0 wt% of magnesium hydroxide; and (E) 2.0 to 15.0 wt% of a copolymer of ethylene and α-olefin comonomer units having 4 to 10 carbon atoms, the copolymer having a strength of 860 to 910 kg / m³. 3 The density as determined according to ISO 1183; (F) a copolymer of 18.0 to 35.0% by weight ethylene and α-olefin comonomer units having 4 to 10 carbon atoms, the copolymer having a density of 920 to 960 kg / m³. 3 The density determined according to ISO 1183, and the melt flow rate MFR5 determined according to ISO 1133 at a temperature of 190°C and a load of 5.0 kg, from 0.05 to 2.50 g / 10 min; and (G) 0 to 8.0% by weight of carbon black, wherein all weight percentages are based on the total weight of the flame retardant polymer composition.

Description

Technical Field

[0001] The present invention relates to a flame-retardant polymer composition and the use of said flame-retardant polymer composition in the manufacture of articles, particularly wires or cables comprising a layer (such as a sheath layer) containing said flame-retardant polymer composition. Background Technology

[0002] Flame retardant compounds are typically limited by mechanical properties (such as tensile strength and tear strength) or flame retardant (FR) properties. There is a growing demand for flame retardant products that meet both mechanical and FR requirements. One example of this high-demand product is the ST12 sheath described in IEC 60840:2020, "Power cables with extruded insulation and their accessories for rated voltages above 30kV (Um = 36kV) up to 150kV (Um = 170kV) - Test methods and requirements" (Um = maximum permissible voltage). Compared to lower-voltage sheaths, this standard has higher mechanical requirements, with a tensile strength of 12.5 MPa and an elongation at break of 300% before and after 10 days of heat aging at 110°C. Modern commercial FR products often suffer from poor tensile properties and / or limited flame retardancy. Another issue with flame-retardant materials is the cracking of cable sheaths on cable reels during installation and use, or even during a fire. The cracking properties of a material can be understood by measuring its tear strength at different temperatures.

[0003] WO 2021 / 111006 A1 discloses a flame-retardant polymer composition that has good flame-retardant properties and acceptable mechanical properties for low-voltage cable applications, but is insufficient to meet the higher mechanical requirements described in IEC 60840:2020.

[0004] Therefore, there is a need in the art for flame-retardant polymer compositions that exhibit sufficient flame retardancy and improved mechanical properties in terms of tensile strength, elongation at break and tear strength, such as those that meet the requirements for cable sheaths of medium-voltage and high-voltage cables as described in IEC 60840:2020. Summary of the Invention

[0005] This invention relates to a flame-retardant polymer composition comprising...

[0006] (A) 2.0 to 15.0% by weight of an ethylene copolymer comprising units selected from the group consisting of methyl acrylate, methyl methacrylate, or mixtures thereof;

[0007] (B) 0 to 4.0% by weight of polyethylene and / or polypropylene containing units derived from maleic anhydride;

[0008] (C) 0.1 to 3.0% by weight of silicone fluid and / or silicone gum;

[0009] (D) 40.0 to 55.0% by weight of magnesium hydroxide;

[0010] (E) A copolymer of 2.0 to 15.0% by weight ethylene and α-olefin comonomer units having 4 to 10 carbon atoms, the copolymer having a content of 860 to 910 kg / m³. 3 The density as determined according to ISO 1183;

[0011] (F) A copolymer of 18.0 to 35.0% by weight ethylene and α-olefin comonomer units having 4 to 10 carbon atoms, the copolymer having a content of 920 to 960 kg / m³. 3 The density determined according to ISO 1183, and the melt flow rate MFR5 determined according to ISO 1133 at a temperature of 190°C and a load of 5.0 kg, ranging from 0.05 to 2.50 g / 10 min; and

[0012] (G) 0 to 8.0% by weight of carbon black,

[0013] All weight percentages are based on the total weight of the flame-retardant polymer composition.

[0014] Furthermore, the present invention relates to an article comprising a flame-retardant polymer composition as described above or below.

[0015] Furthermore, the present invention relates to the use of flame-retardant polymer compositions as described above or below in the manufacture of articles.

[0016] definition

[0017] In the sense of this invention, polyethylene is a polymer having a molar majority (i.e., at least 50 mol%) of ethylene monomer units.

[0018] Ethylene copolymers are polymers having a molar majority of ethylene monomer units and at least one unit of a different chemical moiety (e.g., selected from α-olefins, methyl acrylate, methyl methacrylate, maleic anhydride). The unit of the different chemical moiety can be introduced into the polymer by copolymerization (i.e., comonomerization) or by grafting onto the polymer backbone, as is known in the art.

[0019] In the sense of this invention, polypropylene is a polymer having a molar majority (i.e., at least 50 mol%) of propylene monomer units.

[0020] Propylene copolymers are polymers having a molar majority of propylene monomer units and at least one unit of a different chemical moiety (e.g., selected from maleic anhydride). The unit of the different chemical moiety can be introduced into the polymer by copolymerization (i.e., comonomerization) or by grafting onto the polymer backbone, as is known in the art.

[0021] Throughout this application, the particle size of a portion of the particulate material is described by its particle size distribution. The value d represents a diameter such that, relative to this diameter, x wt% of the particles have a diameter smaller than dx. Therefore, d 50 The value is the "median particle size," at which 50% by weight of all particles are smaller than the indicated particle size.

[0022] The magnesium hydroxide material used as component D) according to the present invention may contain impurities such as calcium oxide, silicon dioxide, and iron oxide. Preferably, component D) contains 80 to 98% by weight of magnesium hydroxide, more preferably greater than 85% by weight, more preferably greater than 90% by weight, and even more preferably greater than 92.5% by weight. The amount and nature of the impurities may vary depending on the source of the starting mineral.

[0023] When the term "comprising" is used in this specification and claims, it does not exclude other undescribed elements of primary or secondary functional importance. For the purposes of this invention, the term "consisting of" is considered a preferred embodiment of the term "comprising." If, hereinafter, a group is defined as including at least a certain number of embodiments, this should also be understood as disclosing a group preferably consisting only of these embodiments. Detailed Implementation

[0024] Component (A)

[0025] The flame-retardant polymer composition comprises 2.0 to 15.0% by weight, preferably 3.0 to 14.0% by weight, more preferably 4.0 to 13.0% by weight, and even more preferably 5.5 to 12.5% ​​by weight of an amount of ethylene copolymer as component (A), based on the total weight of the flame-retardant polymer composition, the ethylene copolymer comprising units selected from the group consisting of methyl acrylate, methyl methacrylate, or mixtures thereof.

[0026] Preferably, component (A) is a copolymer comprising ethylene units and methyl acrylate units, and more preferably a copolymer composed of ethylene units and methyl acrylate units.

[0027] Based on the total weight of component (A), the content of units selected from the group consisting of methyl acrylate, methyl methacrylate, or mixtures thereof, preferably the content of methyl acrylate units is preferably in the range of 10 to 35% by weight, and preferably in the range of 20 to 30% by weight.

[0028] Preferably, component (A) has a concentration of 920 to 960 kg / m³. 3 Within the range, preferably between 935 and 950 kg / m 3 The density is within the range determined according to ISO 1183.

[0029] Preferably, component (A) has an MFR2 measured according to ISO 1133 (2.16 kg, 190 °C) in the range of 0.1 to 10 g / 10 min, more preferably in the range of 0.1 to 5.0 g / 10 min, and more preferably in the range of 0.2 to 0.7 g / 10 min.

[0030] In a preferred embodiment, component (A) comprises a unit having a hydrolyzable silane group, wherein the unit having the hydrolyzable silane group is preferably represented by formula (l):

[0031] R 1 SiR 2 q Y 3-q (I)

[0032] in

[0033] R 1 It is an olefinic unsaturated hydrocarbon group, alkyloxy group, or (meth)acryloyloxy hydrocarbon group.

[0034] Each R 2 It is independently an aliphatic saturated hydrocarbon group.

[0035] Y can be the same or different, and is a hydrolyzable organic group.

[0036] q is 0, 1, or 2.

[0037] Based on the total weight of component (A), the content of comonomer units containing crosslinkable silane groups is preferably from 0.2 to 4.0% by weight, more preferably from 0.4 to 2.0% by weight.

[0038] Suitable components that can be used as component (A) according to the invention are commercially available, for example, those that can be marketed under trade names. AC 1125 was purchased from DuPont (USA).

[0039] Component (B)

[0040] The flame-retardant polymer composition comprises, based on the total weight of the flame-retardant polymer composition, 0 to 4.0% by weight, preferably 0.5 to 3.5% by weight, more preferably 1.0 to 3.0% by weight, and even more preferably 1.5 to 2.5% by weight, of polyethylene and / or polypropylene containing units derived from maleic anhydride as component (B).

[0041] Preferably, component (B) is obtained by copolymerization and / or grafting of polyethylene with maleic anhydride, wherein grafted linear low-density polyethylene is preferred, and more preferably the content of maleic anhydride is in the range of 0.3 to 2.0% by weight.

[0042] Preferably, component (B) has a concentration of 910 to 950 kg / m³. 3 Within the range, preferably between 920 and 940 kg / m³ 3 The density is within the range determined according to ISO 1183.

[0043] Preferably, component (B) has an MFR2 measured according to ISO 1133 (2.16 kg for polyethylene, 190 °C, and 2.16 kg for polypropylene, 230 °C) in the range of 0.5 to 5.0 g / 10 min, preferably in the range of 1.5 to 2.5 g / 10 min.

[0044] Suitable polyethylene and / or polypropylene containing units derived from maleic anhydride, which can be used as component (B) according to the invention, are commercially available, for example, under trade names. The GE300C was purchased from HDC Hyundai EP Co., Ltd.

[0045] Component (C)

[0046] The flame-retardant polymer composition comprises 0.1 to 3.0% by weight, preferably 0.3 to 2.8% by weight, more preferably 0.5 to 2.5% by weight, and even more preferably 0.7 to 2.3% by weight of a silicone fluid and / or silicone rubber compound as component (C) based on the total weight of the flame-retardant polymer composition.

[0047] Preferably, component (C) is a silicone fluid or silicone rubber compound selected from polysiloxane (preferably polydimethylsiloxane) and siloxanes containing alkoxy or alkyl functional groups and mixtures thereof; more preferably, component (C) is an organically modified siloxane.

[0048] Particularly preferred is that component (C) is an organopolysiloxane polymer comprising chemically bonded silanoxy units. Preferably, the silanoxy units are selected from R3SiO 0.5 , R2SiO, R 1SiO 1.5 R 1 R2SiO 0.5 RR 1 SiO, R 1 2SiO, RSiO 1.5 The group consisting of SiO2 units and mixtures thereof, wherein each R independently represents a saturated or unsaturated monovalent hydrocarbon substituent, each R 1 Substituents such as R or substituents selected from the group consisting of hydrogen atom, hydroxyl, alkoxy, aryl, vinyl or allyl.

[0049] Preferably, component (C) has a viscosity of approximately 600 to 300 × 10⁻⁶ at 25°C. 6 Centipoise organopolysiloxane polymers.

[0050] Examples of suitable organopolysiloxanes have been found to have a viscosity of approximately 20 × 10⁻⁶ at 25°C. 6 Centipoise polydimethylsiloxane polymer.

[0051] Preferably, component (C) contains up to 50% by weight of pyrolytic silica filler of the type typically used for curing silicone rubber.

[0052] Suitable silicone fluids and / or silicone materials that can be used as component (C) are commercially available, for example, those that are available as... 6264 is available from Evonik Nutrition & Care GmbH (Germany), and can be obtained from DuPont as DOWCORNING™ AMB-12235 MASTERBATCH, or from Borealis AG (Austria) as FR4897.

[0053] Component (D)

[0054] The flame retardant polymer composition comprises 40.0 to 55.0% by weight, preferably 42.5 to 53.5% by weight, more preferably 45.0 to 52.5% by weight, and even more preferably 47.5 to 51.0% by weight of magnesium hydroxide as component (D) based on the total weight of the flame retardant polymer composition.

[0055] Preferably, component (D) is ground or precipitated magnesium hydroxide, more preferably ground magnesium hydroxide.

[0056] Precipitated magnesium hydroxide is generally more expensive than ground magnesium hydroxide, but precipitated magnesium hydroxide remains the dominant type because it does not significantly degrade the mechanical properties of the polymer matrix due to its smaller particle size and more uniform particle size distribution. The specific combination of components in the flame-retardant polymer compositions of this invention also allows for the use of ground magnesium to achieve good mechanical properties.

[0057] According to the present invention, "ground magnesium hydroxide" refers to magnesium hydroxide obtained by grinding magnesium hydroxide-based minerals such as brucite and the like. Brucite exists in its pure form, or more often in combination with other minerals such as calcite, aragonite, talc, or magnesite, and often exists in layered form between silicate deposits, such as in serpentine asbestos, chlorite, or schist.

[0058] Minerals containing magnesium hydroxide can be ground according to the following technique: advantageously, the mineral obtained from the mine is first crushed, then ground, preferably repeatedly, with each crushing / grinding step followed by a sieving step. Grinding can be carried out under wet or dry conditions, for example by ball milling, optionally in the presence of a grinding aid (e.g., polyethylene glycol or the like).

[0059] Suitable milled magnesium hydroxide that can be used as component (D) is commercially available, for example, under the trade name [product name missing]. The 3.5C was purchased from Europiren BV (Netherlands).

[0060] In a preferred embodiment, component (D) is preferably used in particulate form, the surface of which has been treated with at least one saturated or unsaturated fatty acid or its metal salt containing 8 to 24 carbon atoms, such as, for example: oleic acid, palmitic acid, stearic acid, isostearic acid, lauric acid; magnesium stearate or zinc stearate or magnesium oleate or zinc stearate; etc.

[0061] Component (D) can also be used without surface treatment.

[0062] Preferably, component (D) is a median particle size d. 50 The milled magnesium hydroxide is in the range of 1.0 to 10.0 μm, preferably in the range of 2.0 to 5.0 μm, and even more preferably in the range of 3.0 to 4.0 μm.

[0063] Preferably, component (D) is ground magnesium hydroxide that has been surface-treated with stearic acid.

[0064] Therefore, based on the weight of the ground magnesium hydroxide, the stearic acid content is preferably 1.0 to 3.0% by weight, more preferably 1.5 to 2.5% by weight.

[0065] More preferably, component (D) has a BET surface area of ​​1 to 20 m². 2 Within the range of / g, preferably in the range of 5 to 12m 2 Magnesium hydroxide that has been ground or precipitated within the range of / g.

[0066] Component (E)

[0067] The flame-retardant polymer composition comprises 2.0 to 15.0% by weight, preferably 3.0 to 14.0% by weight, more preferably 4.0 to 13.0% by weight, and even more preferably 5.0 to 12.5% ​​by weight of ethylene as component (E) and α-olefin comonomer units having 4 to 10 carbon atoms, based on the total weight of the flame-retardant polymer composition, the copolymer having a content of 860 to 910 kg / m³. 3 The density is determined according to ISO 1183.

[0068] Preferably, component (E) is a copolymer of ethylene and one or more α-olefin comonomer units selected from 1-butene, 1-hexene and / or 1-octene.

[0069] Preferably, component (E) is selected from copolymers of ethylene and 1-butene, copolymers of ethylene and 1-hexene, and copolymers of ethylene and 1-octene, more preferably copolymers of ethylene and 1-butene and copolymers of ethylene and 1-octene.

[0070] Particularly preferred is that component (E) is a copolymer of ethylene and 1-octene.

[0071] Component (E) has 860 to 910 kg / m³ 3 Preferably 870 to 905 kg / m 3 More preferably 880 to 903 kg / m 3 The density is determined according to ISO 1183.

[0072] Preferably, component (E) has a melt flow rate MFR2 measured according to ISO 1133 (2.16 kg, 190 °C) in the range of 0.1 to 10.0 g / 10 min, more preferably in the range of 0.5 to 5.0 g / 10 min, and even more preferably in the range of 1.0 to 3.5 g / 10 min.

[0073] Preferably, component (E) is polymerized in the presence of a single active site catalyst. Suitably, component (E) is polymerized in a solution polymerization method known in the art.

[0074] It can be used as component (E) with a concentration of 860 to 910 kg / m³ 3Copolymers of ethylene with a density of 4 to 10 carbon atoms and α-olefin comonomer units are commercially available, for example, from Borealis AG (Austria) under the trade names Queo 8201 or Queo 8203.

[0075] Component (F)

[0076] The flame-retardant polymer composition comprises 18.0 to 35.0% by weight, preferably 20.0 to 32.5% by weight, more preferably 22.0 to 30.0% by weight, and even more preferably 24.0 to 28.0% by weight, of ethylene as component (F) and α-olefin comonomer units having 4 to 10 carbon atoms, based on the total weight of the flame-retardant polymer composition, the copolymer having a content of 920 to 965 kg / m³. 3 The density is determined according to ISO 1183, and the melt flow rate MFR5 is determined according to ISO 1133 (5.0 kg, 190 °C) from 0.05 to 2.50 g / 10 min.

[0077] Preferably, component (F) is a copolymer of ethylene and one or more α-olefin comonomer units selected from 1-butene, 1-hexene and / or 1-octene.

[0078] Preferably, component (F) is selected from copolymers of ethylene and 1-butene, copolymers of ethylene and 1-hexene, and copolymers of ethylene and 1-octene, more preferably copolymers of ethylene and 1-butene and copolymers of ethylene and 1-hexene.

[0079] Particularly preferred is that component (F) is a copolymer of ethylene and 1-hexene.

[0080] Component (F) has a concentration of 920 to 965 kg / m³. 3 Preferably 930 to 963 kg / m 3 More preferably 940 to 960 kg / m 3 The density is determined according to ISO 1183.

[0081] In one embodiment, component (F) is a natural resin of a copolymer of ethylene and α-olefin comonomer units having 4 to 10 carbon atoms, i.e., carbon black-free.

[0082] In the described embodiment, preferably, component (F) has a concentration of 920 to 955 kg / m³. 3 Preferably 930 to 953 kg / m 3 More preferably 940 to 950 kg / m 3 The density is determined according to ISO 1183.

[0083] In another embodiment, component (F) is a black resin of a copolymer of ethylene and α-olefin comonomer units having 4 to 10 carbon atoms, i.e., comprising up to 5.0% by weight, preferably up to 3.5% by weight, of carbon black.

[0084] In the described embodiment, preferably, component (F) has a concentration of 930 to 965 kg / m³. 3 Preferably 940 to 963 kg / m 3 More preferably 950 to 960 kg / m 3 The density is determined according to ISO 1183.

[0085] In addition, component (F) has a melt flow rate MFR5 of 0.05 to 2.50 g / 10 min, preferably 0.10 to 1.50 g / 10 min, more preferably 0.15 to 1.00 g / 10 min, and even more preferably 0.20 to 0.50 g / 10 min as determined according to ISO 1133 (5.0 kg, 190 °C).

[0086] Furthermore, preferably, component (F) has a melt flow rate (MFR) of 2.0 to 40.0 g / 10 min, more preferably 3.0 to 30.0 g / 10 min, more preferably 4.0 to 20.0 g / 10 min, and even more preferably 5.0 to 15.0 g / 10 min as determined according to ISO 1133 (21.6 kg, 190 °C). 21 .

[0087] Preferably, component (F) is a multi-peaked, more preferably bi-peaked copolymer of ethylene and α-olefin comonomer units having 4 to 10 carbon atoms.

[0088] Unless otherwise stated, the term "multimodal" herein refers to a multimodal nature in terms of molecular weight distribution, and therefore includes bimodal polymers. Generally, a polyethylene composition containing at least two polyethylene fractions produced under different polymerization conditions results in different (weight-average) molecular weights and molecular weight distributions of the fractions. The prefix "multimodal" relates to the number of different polymer fractions present in the polymer. Thus, for example, a multimodal polymer includes a so-called "bimodal" polymer consisting of two fractions. The form of the molecular weight distribution curve of a multimodal polymer, i.e., the appearance of a graph of the polymer weight fraction as a function of its molecular weight, will show two or more maximum values, or will generally be significantly broadened compared to the curves of individual fractions. For example, if the polymer is produced in a continuous multi-stage process, utilizing reactors connected in series and using different conditions in each reactor, the polymer fractions produced in the different reactors will each have their own molecular weight distribution and weight-average molecular weight. When the molecular weight distribution curve of such a polymer is recorded, the individual curves from these fractions generally come together to form a broadened molecular weight distribution curve of the overall resulting polymer product.

[0089] To prepare component (F), polymerization methods well known to those skilled in the art can be used. Within the scope of this invention, multimodal polymers, such as at least bimodal polymers, are produced by in-situ blending of each component during its polymerization process (so-called in-situ method), or alternatively by mechanically blending two or more separately produced components in a manner known in the art.

[0090] The ethylene copolymers that can be used as component (F) in this invention are preferably obtained by in-situ blending in a multi-stage polymerization process. Thus, the polymer is obtained by in-situ blending in a multi-stage (i.e., two-stage or more-stage) polymerization process including solution, slurry, and gas-phase methods in any order. While different polymerization catalysts can be used in each stage of the process, it is preferred that the same catalyst be used in both stages.

[0091] Therefore, ideally, the polyethylene polymer used in the blends of the present invention is produced in at least two stages of polymerization using a single-active-center catalyst or a Ziegler-Natta catalyst. Thus, for example, two slurry reactors or two gas-phase reactors, or any combination thereof, can be employed in any order. However, it is preferable to use slurry polymerization in a loop reactor followed by gas-phase polymerization in a gas-phase reactor to prepare the ethylene copolymer.

[0092] The loop reactor-gas phase reactor system is a Borealis technology, namely BORSTAR. TM Reactor systems are well-known. For example, such a multi-stage method is disclosed in EP517868.

[0093] The conditions used in this method are well known. For slurry reactors, the reaction temperature is typically in the range of 60 to 110°C, for example 85 to 110°C; the reactor pressure is typically in the range of 5 to 80 bar, for example 50 to 65 bar; and the residence time is typically in the range of 0.3 to 5 hours, for example 0.5 to 2 hours. The diluent used is typically an aliphatic hydrocarbon with a boiling point in the range of -70 to +100°C, such as propane. In such reactors, polymerization can be carried out under supercritical conditions if desired. Slurry polymerization can also be carried out in bulk, where the reaction medium is formed from the monomers being polymerized.

[0094] For gas-phase reactors, the reaction temperature is typically in the range of 60 to 115°C, for example, 70 to 110°C; the reactor pressure is typically in the range of 10 to 25 bar; and the residence time is typically 1 to 8 hours. The gases used are typically non-reactive gases, such as nitrogen, or low-boiling hydrocarbons, such as propane, and monomers, such as ethylene. Preferably, the first polymer fraction is produced in a continuously operating loop reactor, wherein ethylene is polymerized in the presence of the polymerization catalyst and chain transfer agent (such as hydrogen) as described above. The diluent is typically an inert aliphatic hydrocarbon, preferably isobutane or propane. The reaction product is then transferred, preferably to a continuously operating gas-phase reactor. A second component is then formed in the gas-phase reactor, preferably using the same catalyst.

[0095] It can be used as component (F) with a concentration of 920 to 965 kg / m³ 3 The copolymer of ethylene and α-olefin comonomer units having 4 to 10 carbon atoms in MFR5 with a density of 0.05 to 2.50 g / 10 min is commercially available, for example, from Borealis AG (Austria) under the trade names Borsafe HE3490-LS-H or Borsafe HE3493-LS-H.

[0096] Component (G)

[0097] The flame retardant polymer composition optionally includes 0 to 8.0% by weight, preferably 0 to 7.5% by weight, more preferably 0 to 6.5% by weight, and even more preferably 0 to 6.0% by weight of carbon black as component (G) based on the total weight of the flame retardant polymer composition.

[0098] Preferably, carbon black is added to the flame-retardant polymer composition as a carbon black masterbatch, which contains 30 to 50% by weight of carbon black in a polyethylene matrix based on the total weight of the carbon black masterbatch. When a carbon black masterbatch is used, the amount of carbon black in the flame-retardant polymer composition includes the amount of the polyethylene matrix.

[0099] Preferably, the carbon black masterbatch has a strength of 1100 to 1200 kg / m³. 3 Preferably 1115 to 1150 kg / m 3 The density is determined according to ISO 1183.

[0100] In one embodiment, the flame-retardant polymer composition does not contain carbon black. In this embodiment, the amount of component (G) in the flame-retardant polymer composition is 0% by weight, and component (F) is a natural resin of a copolymer of ethylene and α-olefin comonomer units having 4 to 10 carbon atoms, the natural resin having a content of 920 to 955 kg / m³. 3 Preferably 930 to 953 kg / m 3 More preferably 940 to 950 kg / m 3 The density is determined according to ISO 1183.

[0101] In a second embodiment, the flame-retardant polymer composition comprises carbon black in the form of component (G). In this embodiment, the amount of component (G) in the flame-retardant polymer composition is 0.5 to 8.0 wt%, 1.0 to 7.5 wt%, preferably 1.5 to 6.5 wt%, more preferably 2.0 to 6.0 wt%, based on the total weight of the flame-retardant polymer composition, and component (F) is a natural resin of a copolymer of ethylene and α-olefin comonomer units having 4 to 10 carbon atoms, the natural resin having a content of 920 to 955 kg / m³. 3 Preferably 930 to 953 kg / m 3 More preferably 940 to 950 kg / m 3 The density is determined according to ISO 1183.

[0102] In a third embodiment, the flame-retardant polymer composition comprises carbon black in the form of a black resin of an ethylene copolymer as component (F). In this embodiment, the amount of component (G) in the flame-retardant polymer composition is 0% by weight, and component (F) is a black resin of a copolymer of ethylene and α-olefin comonomer units having 4 to 10 carbon atoms, the black resin having a carbon content of 930 to 965 kg / m³. 3 Preferably 940 to 963 kg / m 3 More preferably 950 to 960 kg / m 3 The density is determined according to ISO 1183.

[0103] The carbon black masterbatch suitable as component (G) in this invention (which can be used as component (F)) is commercially available, for example, it can be purchased from Borealis AG (Austria) under the trade name Borlink LE7710.

[0104] additive

[0105] The flame-retardant polymer composition according to the present invention may also contain additives.

[0106] According to a preferred embodiment of the present invention, the polymer composition comprises at least one additive, which is preferably selected from the group consisting of slip agents, ultraviolet stabilizers, antioxidants, additive carriers, nucleating agents, mica, anti-scorching agents, and mixtures thereof.

[0107] Based on the total weight of the flame-retardant polymer composition, the additive is preferably present in an amount of 0 to 5.0% by weight, preferably 0.05 to 2.5% by weight, more preferably 0.10 to 1.5% by weight, and even more preferably 0.15 to 1.0% by weight.

[0108] The flame-retardant polymer composition preferably contains an antioxidant comprising a sterically hindered phenolic group or an aliphatic sulfur group. Such compounds are disclosed in EP 1 254 923 A1 as antioxidants particularly suitable for stabilizing polyolefins containing hydrolyzable silane groups.

[0109] Other preferred antioxidants are disclosed in WO 2005 / 003199 A1. Preferably, the antioxidant is present in the composition in an amount of 0.01 to 3% by weight, more preferably 0.05 to 2% by weight, and most preferably 0.08 to 1.5% by weight, based on the total weight of the flame-retardant polymer composition.

[0110] When the flame-retardant polymer composition of the present invention is crosslinked, it may contain a scorch inhibitor. The scorch inhibitor may be a silane-containing scorch inhibitor as described in EP 0 449 939A1. If applicable, the scorch inhibitor may be present in the flame-retardant polymer composition in an amount of 0.3% to 5.0% by weight based on the total weight of the flame-retardant polymer composition.

[0111] Flame retardant polymer compositions

[0112] The flame-retardant polymer composition comprises components (A) to (F) and optional components (G) and additives as described above.

[0113] Preferably, the flame-retardant polymer composition comprises, and more preferably consists of, the following components.

[0114] 3.0 to 14.0% by weight, preferably 4.0 to 13.0% by weight, more preferably 5.5 to 12.5% ​​by weight of component (A);

[0115] 0.5 to 3.5% by weight, preferably 1.0 to 3.0% by weight, more preferably 1.5 to 2.5% by weight of component (B);

[0116] 0.3 to 2.8% by weight, preferably 0.5 to 2.5% by weight, more preferably 0.7 to 2.3% by weight of component (C);

[0117] 42.5 to 53.5% by weight, preferably 45.0 to 52.5% by weight, more preferably 47.5 to 51.0% by weight of component (D);

[0118] 3.0 to 14.0% by weight, preferably 4.0 to 13.0% by weight, more preferably 5.0 to 12.5% ​​by weight of component (E);

[0119] 20.0 to 32.5% by weight, preferably 22.0 to 30.0% by weight, more preferably 24.0 to 28.0% by weight of component (F);

[0120] 0 to 7.5% by weight, preferably 0 to 6.5% by weight, more preferably 0 to 6.0% by weight, of carbon black masterbatch, wherein the carbon black masterbatch contains 30 to 50% by weight of carbon black in a polyethylene matrix based on the total weight of the carbon black masterbatch; and

[0121] 0.05 to 2.5% by weight, preferably 0.10 to 1.5% by weight, more preferably 0.15 to 1.0% by weight, of an additive selected from the group consisting of slip agents, UV stabilizers, antioxidants, additive carriers, nucleating agents, mica, and mixtures thereof.

[0122] All weight percentages are based on the total weight of the flame-retardant polymer composition.

[0123] According to a preferred embodiment of the present invention, the flame-retardant polymer composition is free of calcium borate and zinc borate, and more preferably, the flame-retardant polymer composition is free of any metal borate.

[0124] Another preferred embodiment of the invention specifies that the flame-retardant polymer composition is free of inorganic hypophosphite.

[0125] Preferably, the flame-retardant polymer composition has a tensile strength of 12.5 MPa to 25.0 MPa, more preferably 13.0 to 22.5 MPa, more preferably 13.5 to 21.0 MPa, and even more preferably 14.0 to 20.0 MPa, as determined according to ISO 527-1 and ISO 527-2.

[0126] After the sample is conditioned at 110°C for 240 hours, preferably, the flame-retardant polymer composition has a tensile strength of 12.5 MPa to 25.0 MPa, more preferably 3.0 MPa to 22.5 MPa, more preferably 13.5 MPa to 21.0 MPa, and even more preferably 14.0 MPa to 20.0 MPa, as determined according to ISO 527-1 and ISO 527-2.

[0127] Preferably, the flame-retardant polymer composition preferably exhibits a change in tensile strength of -5.0% to +5.0%, more preferably -3.5% to +3.5%, as the ratio of the tensile strength before adjustment to the tensile strength after adjustment.

[0128] Preferably, the flame-retardant polymer composition has an elongation at break of 350% to 550%, more preferably 370% to 525%, more preferably 390% to 500%, and even more preferably 400% to 480% as determined according to ISO 527-1 and ISO 527-2.

[0129] After the sample is conditioned at 110°C for 240 hours, preferably, the flame-retardant polymer composition has an elongation at break of 300% to 500%, preferably 310% to 475%, more preferably 315% to 450%, and even more preferably 320% to 430% as determined according to ISO 527-1 and ISO 527-2.

[0130] Preferably, the flame-retardant polymer composition preferably exhibits a change in elongation at break of 0% to 20.0%, more preferably 5.0% to 15.0%, as the ratio of the elongation at break before adjustment to the elongation at break after adjustment.

[0131] Further, the flame-retardant polymer composition preferably has a tear strength of 8.5 to 25.0 N / mm, more preferably 10.0 to 22.5 N / mm, and even more preferably 11.0 to 20.0 N / mm, as determined at 23°C according to Method 2 of Clause 2.2.2.2 of BS 6469 section 99.1:1992, HD 605S2:2008.

[0132] Furthermore, preferably, the flame-retardant polymer composition has a tear strength of 8.5 to 20.0 N / mm, more preferably 9.0 to 17.5 N / mm, and even more preferably 10.0 to 15.0 N / mm, as determined by Method 2 of Section 2.2.2.2 of BS 6469:1992, HD 605S2:2008 at 50°C.

[0133] Preferably, the flame-retardant polymer composition has a strength of 75 to 250 kW / m³. 2 More preferably 75 to 230 kW / m 2 More preferably 75 to 210 kW / m 2The peak heat release rate (pHRR) was determined in a cone calorimetry test according to ISO 5660-1.

[0134] Further, preferably, the flame-retardant polymer composition has a viscosity of 0.3 to 7.5 m. 2 Preferably, the depth is 0.5 to 6.5 m. 2 More preferably 0.7 to 5.5m 2 Total Smoke Production (TSP) was determined in a cone calorimetry test according to ISO 5660-1.

[0135] Therefore, the flame-retardant polymer composition according to the invention exhibits good flame-retardant properties and improved mechanical properties with respect to tensile strength, elongation at break and tear strength, and preferably meets the requirements of ST12 sheath as described in IEC 60840:2020 "Extruded insulated power cables and accessories thereof with rated voltages above 30 kV (Um = 36 kV) to 150 kV (Um = 170 kV) - Test methods and requirements" (Um = maximum permissible voltage).

[0136] Products

[0137] The present invention also relates to articles comprising flame-retardant polymer compositions as described above or below in all aspects and embodiments thereof.

[0138] Preferably, the article is a wire or cable, which includes at least one layer comprising a flame-retardant polymer composition.

[0139] According to a preferred embodiment of the present invention, at least one layer obtained from the polyolefin composition of the present invention may be cross-linked.

[0140] Wires or cables can be produced by co-extruding different layers onto a conductive core. Then, optionally, crosslinking is performed, preferably by moisture curing, in the case that component (A) contains comonomer units containing crosslinkable silane groups, wherein the silane groups are hydrolyzed under the influence of water or steam. Preferably, moisture curing is carried out in a sauna or water bath at a temperature of 70 to 100°C or under ambient conditions.

[0141] The flame-retardant polymer composition according to the invention can be extruded around a wire or cable to form an insulation layer or sheath layer, or can be used as a padding compound.

[0142] The flame-retardant polymer composition is then optionally crosslinked.

[0143] According to a preferred embodiment, the wire or cable includes an insulation layer, which preferably comprises or consists of a material selected from or composed of cross-linked or thermoplastic polyethylene, thermoplastic polypropylene, or flame-retardant polyolefin. Suitable flame-retardant polyolefins are particularly described in WO 2013 / 159942 A2. Suitable thermoplastic insulating materials are disclosed, for example, in WO 2007 / 137711 A1 or WO 2013 / 1599442A2, and are commercially available from Borealis AG (Austria), for example, under the trade names FR4802, FR4803, FR4807, FR6082, FR6083, and FR4804. Commercially available cross-linkable insulating materials are also available from Borealis AG (Austria) under the trade names FR4450 and FR4451.

[0144] Depending on the application, the thickness of the insulation layer of the low-voltage power cable can range from 0.4 mm to 3.0 mm, preferably less than 2.0 mm. Preferably, the insulation material is directly coated onto the electrical conductor.

[0145] In a preferred embodiment, the flame-retardant polymer composition according to the invention is contained in the sheath of a wire or cable, preferably in the sheath of a medium-voltage (MW) or high-voltage (HV) cable.

[0146] MW and HV cables typically have a conductor surrounded by an inner semiconductor layer, followed by an insulation layer, then an outer semiconductor layer, and a sheath layer as a protective outer layer. The main difference between MW and HV cables lies in the thickness of the insulation layer.

[0147] MW cables are typically classified according to their maximum permissible voltage Um, ranging from 1kV to 36kV.

[0148] HW cables are typically classified according to their maximum permissible voltage Um, ranging from 36kV to 230kV.

[0149] All preferred aspects and embodiments of the flame-retardant polymer composition described above should also apply to articles according to the invention.

[0150] use

[0151] Furthermore, the present invention relates to the use of flame-retardant polymer compositions as described above or below in the production of articles such as flame-retardant layers of wires or cables.

[0152] All preferred aspects and embodiments of the flame-retardant polymer compositions and articles described above shall also apply to articles according to the invention.

[0153] Experimental Section

[0154] a) Measurement method

[0155] Unless otherwise defined, the following definitions of terms and measurement methods apply to the above general description of the invention and the following embodiments.

[0156] Melt flow rate (MFR)

[0157] MFR was measured according to ISO 1133 (Davenport R-1293 from Daventest Ltd).

[0158] For polyethylene, the MFR value is calculated at 190°C under three different loads: 2.16 kg (MFR2), 5.0 kg (MFR5), and 21.6 kg (MFR6). 21 ) was measured.

[0159] For polypropylene, the melt flow rate was measured at 230°C under the same load.

[0160] density

[0161] Density was measured according to ISO 1183-1 - Method A (2019). Sample preparation was performed by compression molding according to ISO 1872-2:2007.

[0162] Comonomer content in component (A)

[0163] Quantitative analysis of microstructure using NMR spectroscopy

[0164] Quantitative nuclear magnetic resonance (NMR) spectroscopy is used to quantify the comonomer content of polymers.

[0165] Quantitative data were recorded in the molten state using a Bruker Avance III 500 NMR spectrometer operating at 500.13 MHz. 1 ¹H NMR spectroscopy. Nitrogen gas was used for all pneumatic devices at 150°C. 13 All spectra were recorded using a C-optimized 7mm magic angle rotation (MAS) probe. Approximately 200 mg of material was loaded into a 7mm outer diameter zirconia MAS rotor and rotated at 4 kHz. This setup was chosen primarily for the high sensitivity required for rapid identification and accurate quantification {klimke06, parkinson07, castignolles09}. A 2-second cycle delay was used to utilize standard single-pulse excitation {pollard04, klimke06}. A total of 16 transient signals were acquired for each spectrum.

[0166] Quantitative analysis was performed using a customized automated spectral analysis program. 1The 1H NMR spectra were processed, integrated, and quantitatively determined. The bulk ethylenemethylene (or bulk ethylene-methyl) signal was referenced at 1.33 ppm for all chemical shifts.

[0167] The attribution of methyl acrylate (MA) inclusion is {brandolini01}:

[0168]

[0169] Characteristic signals resulting from the incorporation of methyl acrylate into various possible comonomer sequences were observed. Considering the number of reporter nuclei for each comonomer, the total amount of methyl acrylate incorporation was quantified using the integral of the signal at 3.6 ppm assigned to the 1MA site:

[0170] MA=I 1MA / 3

[0171] Use bulk aliphatic (l) in the range of 0.00 to 3.00 ppm 本体 The ethylene content is quantified by integrating the signal. The total ethylene content is calculated based on the bulk integral and by compensating for observed comonomers.

[0172] E = (1 / 4) * [I] 本体 -3*MA]

[0173] The total mole fraction of methyl acrylate in the polymer is calculated as follows:

[0174] fMA = MA / (E + MA)

[0175] The total monomer content of methyl acrylate, expressed as a mole percentage, is calculated using the standard method based on the mole fraction:

[0176] MA [moles %] = 100 * fMA

[0177] The total monomer content of methyl acrylate, expressed as a weight percentage, is calculated in a standard manner by mole fraction:

[0178] MA[weight%]=100*(fMA*86.09) / ((fMA*86.09)+((1-fMA)*28.05))

[0179] klimke06 Klimke, K., Parkinson, M., Piel, C., Kaminsky, W., Spiess, HW, Vlfilhelm, M., Macromol. Chem. Phys. 2006; 207:382.

[0180] parkinson07 Parkinson, M., Klimke, K., Spiess, HW, V\filhelm, M., Macromol. Chem. Phys. 2007; 208:2128.

[0181] pollard04 Pollard,M.,Klimke,K.,Graf,R.,Spiess,HW,V\filhelm,M.,Sperber,O.,Piel,C.,Kaminsky,W.,Macromolecules 2004;37:813.

[0182] castignolle309 Castignolles,P.,Graf,R.,Parkinson,M.,V\filhelm,M.,Gaborieau,M.,Polymer 50(2009)2373.

[0183] brandolini01 AJBrandolini, DD.Hills, "NMR spectra of polymers andpolymer additives", Marcel Deker Inc., 2000.

[0184] Median granularity (d) 50 )

[0185] The median particle size of metal hydroxides can be measured by laser diffraction (ISO 13320), dynamic light scattering (ISO 22412), or sieve analysis (ASTM D 1921-06). For the metal hydroxides used in the working examples, the median particle size d was determined by laser diffraction. 50 The determination of the value. Any limitation in the claims shall refer to the values ​​obtained from laser diffraction (ISO 13320).

[0186] BET surface area

[0187] The surface area of ​​BET was determined according to ISO 9277 (2010).

[0188] Manufacturing of belts used for determining tensile strength and elongation at break

[0189] To determine tensile strength and elongation at break, a 1.8 mm strip was produced on a Collin TeachLine E20T belt extruder with a 4.2:1, 20D compression screw and a diameter of 20 mm. The temperature distribution was 150 / 160 / 170 °C, and the screw speed was 55 rpm.

[0190] Tensile test

[0191] Tensile testing was performed using an Alwetron TCT 10 tensile testing apparatus according to ISO 527-1 and ISO 527-2. Ten specimens were punched from the plate using ISO 527-2 / 5A specimens and placed in a climate chamber at a relative humidity of 50 ± 5% and a temperature of 23°C for at least 16 hours prior to testing.

[0192] To allow for conditioning, ten samples were placed in a climate chamber at 110°C for at least 240 hours prior to testing.

[0193] The specimen was placed vertically between a clamp spaced 50 ± 2 mm apart, an elongation meter clamp spaced 20 mm apart, and a 1 kN load cell. The accurate width and thickness of each specimen were measured and recorded before testing. Each specimen was subjected to tensile testing at a constant speed of 50 mm / min until fracture, with at least six approved parallel tests performed. In highly filled systems, results often vary considerably; therefore, intermediate values ​​were used to extract individual values ​​for elongation at break (%) and tensile strength (MPa).

[0194] Tear resistance (as determined by Elmandorf tear (N) test):

[0195] Tear resistance was determined according to Method 2 of Section 99.1 of BS6469:1992, HD 605S2:2008, Clause 2.2.2.2.

[0196] This method describes how to measure tear resistance in a 1 mm thick cable sample or a sheath material on a molded sheet. Using a notched specimen, the tear force is measured using a tensile testing machine at 500 mm / min and with a 50 mm distance between the tensile test fixtures. Tear resistance is calculated by dividing the maximum force required to tear the sample by the sample thickness.

[0197] Compression molding

[0198] Plates for limiting oxygen index and vertical burning tests were prepared by compression molding (Collin R 1358, version: 2 / 060510) according to ISO 293. Granules were pressed between two polyester (Mylar) films and positioned within a specific frame of the correct shape and size (3 × 100 × 100 mm). The samples were compressed by applying a pressure of 20 bar at 170°C for 1 minute, followed by applying a pressure of 200 bar at the same temperature for 5 minutes. The remaining compression was carried out at the same high pressure with a cooling rate of 15°C / min for 9 minutes. The amount of granules used per plate was calculated using a material density exceeding 10% by weight.

[0199] Flame retardancy

[0200] Flame retardancy is measured in cone calorimetry according to ISO 5660-1 using peak heat release rate (pHRR) and total smoke production (TSP).

[0201] A cone calorimeter is a device used to study the combustion behavior of small samples of various materials in the condensed state. It is widely used in fire safety engineering. It collects data on ignition time, mass loss, combustion products, heat release rate, and other parameters related to its combustion performance. The device typically allows fuel samples to be exposed to varying heat fluxes on their surface. The principle behind the heat release rate measurement is based on the direct relationship between the total heat of combustion of any organic material and the amount of oxygen required for combustion.

[0202] Samples measuring 3×100×100 mm were prepared by compression molding. Then, at 35 kW / m²... 2 A conical test was conducted using a constant heat flux and a 60 mm sample-to-heater distance. Peak heat release was the maximum heat release during the conical combustion test. Black smoke production was measured using a laser within the conical tube.

[0203] b) Materials used

[0204] Component (A)

[0205] "EMA" is a copolymer of ethylene and methyl acrylate (weight ratio = 75:25), with an MFR2 of 0.4 g / 10 min and a strength of 944 kg / m³. 3 The density can be named AC 1125 was purchased from DuPont (USA).

[0206] Component (B)

[0207] “LLDPE-MAH” is linear low-density polyethylene grafted with maleic anhydride (maleic anhydride content = 0.5 to 1.0 wt%, MFR2 = 2.0 g / 10 min, density = 930 kg / m³). 3 (Can be the product name) The GE300C was purchased from HDC Hyundai EP Co., Ltd.

[0208] Component (C)

[0209] "OMS-1" is a masterbatch containing 50% by weight of organically modified siloxane in an LDPE matrix, and can be used as... 6264 was purchased from Evonik Nutrition & Care GmbH (Germany).

[0210] "OMS-2" is a pure liquid organic-modified siloxane (same as OMS-1), and can be used as... V-Si-4042 was purchased commercially from Evonik Nutrition & Care GmbH (Germany).

[0211] Component (D)

[0212] “MDH-1” is a type of magnesium hydroxide (ground magnesium hydroxide) produced and commercially available by Europiren BV (Netherlands). 3.5C), which has a d of 3.5μm 50 , in 7 to 10m 2 The specific surface area is within the range of / g and is coated with 2% stearic acid by weight.

[0213] The chemical composition is: Mg(OH)2 > 92.8 wt%, CaO < 2.3 wt%, SiO2 < 1.3 wt%, Fe2O3 < 0.13 wt%.

[0214] Component (E)

[0215] "VLDPE" is an extremely low-density copolymer of ethylene and 1-octene, with a density of 883 kg / m³. 3 With a density of 1.1 g / 10 min and an MFR2 of 1.1 g / 10 min, it is commercially available from Borealis AG (Austria) as Queo 8201.

[0216] Component (F)

[0217] HDPE-1 is a natural high-density copolymer of ethylene and 1-hexene, with a density of 949 kg / m³. 3 With a density of 0.23 g / 10 min and an MFR5 of 0.23 g / 10 min, it is commercially available from Borealis AG (Austria) as HE3493-LS-H.

[0218] HDPE-2 is a natural high-density copolymer of ethylene and 1-butene, with a density of 944 kg / m³. 3 The density, MFR2 of 1.7 g / 10 min and MFR5 of 5.1 g / 10 min are commercially available as HE6068 from Borealis AG (Austria). HDPE-2 has a higher MFR5 than claimed and is therefore considered to be a component comparable to component (F).

[0219] Component (G)

[0220] "CBMB" has a density of 1135 kg / m³. 3Thermoplastic black polyethylene compound, used as carbon black masterbatch, is commercially available from Borealis AG (Austria) as Borlink LE7710.

[0221] Other components

[0222] “AO” is a high molecular weight sterically hindered phenolic antioxidant that is commercially available from BASF SE as lrganox 1010.

[0223] “UV” is a synergistic blend of Chimassorb 944 and Tinuvin 622, used as a light stabilizer, and is commercially available from BASF SE as Tinuvin 783FDL.

[0224] c) Preparation of flame-retardant polymer compositions

[0225] The polymer compositions of the embodiments (IE1 to IE3) and comparative examples (CE1 to CE6) of the present invention were produced by mixing the components together in a Buss-co-kneader (46 mm) at a screw speed of 225 rpm and at set temperatures of 180°C in zone 1 and 160°C in zone 2. The screw of the mixer was heated to 120°C. The screw temperature of the extruder was 160°C, and the barrel was heated to 170°C at a rotation speed of 4 rpm. All components were added to port 1. The amounts of different components in the polymer compositions of the embodiments and comparative examples of the present invention and the properties of the polymer compositions are listed in Table 1 below. The properties of the embodiments are also shown in Table 1.

[0226] It can be seen that, compared with embodiments IE1-IE3 of the present invention, comparative example CE6, which reflects embodiment IE2 of WO 2021 / 111006 A1, shows poorer mechanical properties.

[0227] Compared with Examples IE1-IE3 of the present invention, the difference is that Comparative Example CE5, which uses a lower amount of a different component (F) (not falling within the scope of the present invention), exhibits poorer mechanical properties and poorer pHRR flame retardant properties.

[0228] Compared with embodiments IE1-IE3 of the present invention, the adjusted comparative examples CE1-CE4 (which differ from the embodiments of the present invention in that the amount of component (F) is lower) all showed lower tear strength (especially at 50°C) and higher changes in mechanical properties (especially elongation at break).

[0229] Table 1: Composition and Performance of the Examples

[0230]

Claims

1. A flame-retardant polymer composition comprising... (A) 2.0 to 14.0% by weight of an ethylene copolymer comprising 20 to 30% by weight of units selected from the group consisting of methyl acrylate, methyl methacrylate or mixtures thereof, based on the total weight of component (A); (B) 0 to 4.0% by weight of polyethylene and / or polypropylene containing units derived from maleic anhydride; (C) 0.1 to 3.0% by weight of silicone fluid and / or silicone rubber compound; (D) 40.0 to 55.0% by weight of magnesium hydroxide; (E) A copolymer of 2.0 to 15.0% by weight ethylene and α-olefin comonomer units having 4 to 10 carbon atoms, said copolymer having a content of 860 to 910 kg / m³. 3 The density as determined according to ISO 1183; (F) A copolymer of 18.0 to 35.0% by weight ethylene and α-olefin comonomer units having 4 to 10 carbon atoms, said copolymer having a content of 930 to 965 kg / m³. 3 The density determined according to ISO 1183, and the melt flow rate MFR5 determined according to ISO 1133 at a temperature of 190°C and a load of 5.0 kg, ranging from 0.05 to 2.50 g / 10 min; and (G) 0 to 8.0% by weight of carbon black, All weight percentages are based on the total weight of the flame-retardant polymer composition.

2. The flame-retardant polymer composition according to claim 1, wherein component (A) has a concentration of 920 to 960 kg / m³. 3 The density as determined according to ISO 1183 within the range of 0.1 to 10 g / 10 min and the melt flow rate MFR2 as determined according to ISO 1133 at a temperature of 190 °C and a load of 2.16 kg.

3. The flame-retardant polymer composition according to claim 1 or 2, wherein component (A) further comprises a unit having a hydrolyzable silane group, wherein the amount of said unit having a hydrolyzable silane group is in the range of 0.2 to 4.0% by weight based on the total weight of component (A), wherein said unit having a hydrolyzable silane group is represented by formula (I). R 1 SiR 2 q Y 3-q (I) in R 1 It is an olefinic unsaturated hydrocarbon group, alkyloxy group, or (meth)acryloyloxy hydrocarbon group. Each R 2 It is independently an aliphatic saturated hydrocarbon group. Y can be the same or different, and is a hydrolyzable organic group. q is 0, 1, or 2.

4. The flame-retardant polymer composition according to claim 1 or 2, wherein component (B) has a concentration of 910 to 950 kg / m³. 3 The density as determined according to ISO 1183 within the range of 0.5 to 5.0 g / 10 min and the melt flow rate MFR2 as determined according to ISO 1133 for polyethylene at 190°C or for polypropylene at 230°C and under a load of 2.16 kg.

5. The flame-retardant polymer composition according to claim 1 or 2, wherein component (C) is a silicone resin fluid or silicone rubber compound selected from the group consisting of polysiloxanes, siloxanes containing alkoxy or alkyl functional groups, and mixtures thereof.

6. The flame-retardant polymer composition according to claim 1 or 2, wherein component (C) is polydimethylsiloxane.

7. The flame-retardant polymer composition according to claim 1 or 2, wherein component (C) is an organically modified siloxane.

8. The flame-retardant polymer composition according to claim 1 or 2, wherein component (D) is ground or precipitated magnesium hydroxide.

9. The flame-retardant polymer composition according to claim 1 or 2, wherein component (D) is ground magnesium hydroxide that has been surface-treated with stearic acid.

10. The flame-retardant polymer composition according to claim 1 or 2, wherein component (E) is a copolymer of ethylene and 1-octene.

11. The flame-retardant polymer composition according to claim 1 or 2, wherein component (F) is a copolymer of ethylene and 1-hexene.

12. The flame-retardant polymer composition according to claim 1 or 2, comprising the following components 3.0 to 14.0% by weight of component (A); 0.5 to 3.5% by weight of component (B); 0.3 to 2.8% by weight of component (C); 42.5 to 53.5% by weight of component (D); 3.0 to 14.0% by weight of component (E); 20.0 to 32.5% by weight of component (F); 0 to 7.5% by weight of carbon black masterbatch, said carbon black masterbatch comprising 30 to 50% by weight of carbon black (G) based on the total weight of said carbon black masterbatch in a polyethylene matrix; and 0.05 to 2.5% by weight of additives selected from the group consisting of lubricants, UV stabilizers, antioxidants, additive carriers, nucleating agents, mica, anti-scorching agents, and mixtures thereof. All weight percentages are based on the total weight of the flame-retardant polymer composition.

13. The flame-retardant polymer composition according to claim 1 or 2, comprising the following components 3.0 to 14.0% by weight of component (A); 0.5 to 3.5% by weight of component (B); 0.3 to 2.8% by weight of component (C); 42.5 to 53.5% by weight of component (D); 3.0 to 14.0% by weight of component (E); 20.0 to 32.5% by weight of component (F); 0 to 7.5% by weight of carbon black masterbatch, said carbon black masterbatch comprising 30 to 50% by weight of carbon black (G) based on the total weight of said carbon black masterbatch in a polyethylene matrix; and 0.05 to 2.5% by weight of additives selected from the group consisting of lubricants, UV stabilizers, antioxidants, additive carriers, nucleating agents, mica, anti-scorching agents, and mixtures thereof. All weight percentages are based on the total weight of the flame-retardant polymer composition.

14. The flame-retardant polymer composition according to claim 1 or 2, having one or more of the following properties: • Tensile strength from 12.5 MPa to 25.0 MPa, as determined according to ISO 527-1 and ISO 527-2; • Tensile strength of specimens ranging from 12.5 MPa to 25.0 MPa, determined according to ISO 527-1 and ISO 527-2 after conditioning at 110°C for 240 hours. • Changes in tensile strength from -5.0% to +5.0% as the ratio of the tensile strength before adjustment to the tensile strength after adjustment; • Elongation at break of 350% to 550% as determined by ISO 527-1 and ISO 527-2; • Elongation at break, measured according to ISO 527-1 and ISO 527-2, after conditioning the specimen at 110°C for 240 hours at 300% to 500% of its original value. • Changes in elongation at break as the ratio of unadjusted elongation at break to adjusted elongation at break, from 0% to 20.0%. • Tear strength at 23°C, measured according to Section 99.1 of BS 6469:1992, HD 605 S2:2008, Clause 2.2.2.2, Method 2, at 23°C, with a strength of 8.5 to 25.0 N / mm; and / or • Tear strength at 50°C, measured in accordance with Section 99.1 of BS 6469:1992, and Section 2.2.2.2 of HD 605 S2:2008, of 8.5 to 20.0 N / mm.

15. The flame-retardant polymer composition according to claim 1 or 2, having one or all of the following properties: • 75 to 250 kW / m 2 Peak heat release rate (pHRR) as determined in a cone calorimetry test according to ISO 5660-1; and / or • 0.3 to 7.5 m 2 Total smoke production (TSP) was determined in a cone calorimetry test according to ISO 5660-1.

16. An article comprising a flame-retardant polymer composition according to any one of claims 1 to 15.

17. The article of claim 16, wherein it is a wire or cable comprising at least one layer comprising the flame-retardant polymer composition of any one of claims 1 to 15.

18. The article of claim 16, wherein it is a high-voltage cable comprising at least one layer comprising the flame-retardant polymer composition of any one of claims 1 to 15.

19. The article of claim 17 or 18, wherein the layer is a sheath layer.

20. Use of the flame-retardant polymer composition according to any one of claims 1 to 15 in a flame-retardant layer of a wire or cable.

Images