Ultrahigh temperature, low scorch process for preparing crosslinkable compound compositions

Abstract

An ultra-high temperature, low scorch process is provided for the rapid preparation of a crosslinkable compound composition comprising a homogeneous mixture of a thermoplastic polyolefin, an antioxidant, and a curing agent additive comprising one or more organic peroxides and one or more polyalkenyl crosslinking aids. The process avoids soak towers and long soak times, and also produces homogeneous compound compositions that can be fully cross-linked, in which premature cross-linking of thermoplastic polyolefins is reduced to minimal or no premature cross-linking.

Description

[0001] This technical field includes methods for preparing cross-linkable polyolefin formulations.

[0002] Patents in this field include US 5,245,084 and US 9,957,405 B2; and US 10,941,278 B2. Patent applications published in this field include CN 101747553 A; CN 109370003 A; EP 3 192 633 A1; GB1535038A; US 2020 / 0181374 A1; US ​​2020 / 0189166 A1; US ​​2021 / 0139671 A1; WO 2013 / 112781 A1; WO 2019 / 000311 A1; and WO 2019 / 000654 A1. Background Art

[0003] A decades-old method for preventing premature crosslinking or "scorching" of a crosslinkable polyolefin composition containing an organic peroxide is to immerse the organic peroxide into particles of a penultimate composition containing a polyolefin and a non-curing agent additive (e.g., an antioxidant). This is performed on a large scale using one or more soaking towers. Peroxide-free particles are first prepared by melt-blending the non-curing agent additive into the melt of the polyolefin, followed by granulation (e.g., granulation) of the resulting blended mixture to obtain solid particles of the penultimate composition containing no peroxide. The melt-blending / granulation step can be performed rapidly in less than 1 hour in total. Next, the pellets are added to the soaking tower and the organic peroxide is immersed in the solid particles at a temperature far below the -OO- bond cleavage temperature of the organic peroxide (e.g., 50°C to 80°C for dicumyl peroxide) and the melt temperature of the solid particles but high enough to accelerate the migration of the organic peroxide into the solid particles. Soaking typically requires 6 to 12 hours, which undesirably makes the total production time multiple times of the melt compounding / granulation time. Moreover, soaking can undesirably produce non-uniform soaked particles with a concentration gradient of organic peroxide, with more organic peroxide at the surface and less in the center of the solid particles. Furthermore, soaking towers undesirably add an additional expense of 35% to 50% to the cost of building a new production line. Summary of the invention

[0004] The present inventors have discovered an ultra-high temperature, low scorch method for rapidly preparing a crosslinkable compound composition comprising a homogeneous mixture of a thermoplastic polyolefin, an antioxidant, and a curing agent additive comprising one or more organic peroxides and one or more polyene-based crosslinking aids. The method avoids soak towers and lengthy soak times, and also produces a fully crosslinkable homogeneous compound composition wherein premature crosslinking of the thermoplastic polyolefin is minimized or eliminated. BRIEF DESCRIPTION OF THE DRAWINGS

[0005] Figure 1 An example of a melt compounding line (2) that can be used in the process of the present invention is depicted.

[0006] Figure 2 An alternative example of a melt compounding line (2) that can be used in the process of the present invention is depicted.

[0007] Figure 3 An example of a melt compounding line (2) for preparing a crosslinkable compound composition described later in Inventive Examples is depicted.

[0008] Figure 4 An embodiment is described in which material (a) is fed.

[0009] Figure 5 An embodiment is described in which material (b) is fed.

[0010] Figure 6 An embodiment is described in which material (c) is fed. DETAILED DESCRIPTION

[0011] An ultra high temperature, low scorch process for rapidly preparing a crosslinkable compound composition comprising a homogeneous mixture of a thermoplastic polyolefin, an antioxidant, and a curing agent additive comprising one or more organic peroxides and one or more polyene-based crosslinking aids is described. The process avoids soak towers and lengthy soak times and also produces a fully crosslinkable homogeneous compound composition wherein premature crosslinking of the thermoplastic polyolefin is minimized or eliminated.

[0012] The method can be applied to prepare extruded articles. Examples of extruded articles are coatings, films and laminates. Extruded articles also include pellets of the crosslinkable compound composition, which can be stored and later melt-extruded into the aforementioned articles. Because the degree of premature crosslinking or scorching experienced during the method is so small, the crosslinkable compound composition in the extruded article is fully curable to prepare a cured article. These include fully cured insulation layers of power and telecommunication cables.

[0013] Beneficially, the inventive method is more effective, faster and cheaper than the comparative method based on soaking organic peroxide described later. The improved efficiency of the inventive method includes using fewer unit operations (e.g., no soaking tower) and can use less energy than the comparative method. The method is flexible because it can be applied to different embodiments.

[0014] One embodiment includes an ultra-high temperature, low scorch (including scorch-free) method for preparing a crosslinkable compound composition comprising a homogeneous mixture of a combination of one or more thermoplastic polyolefins, one or more antioxidants and a curing agent additive, the combination of the curing agent additive comprising one or more organic peroxides (COOC-containing compounds) and one or more polyolefin crosslinking aids (non-polymeric compounds containing two or more olefin groups, which olefin groups can be selected from the group consisting of vinyl, allyl, acryloyl and methacryloyl groups), the method comprising: providing a melt compounding device (e.g., an extruder), the melt compounding device having, in sequence, a solid conveying zone (including a device, such as a hopper for conveying polymer solids), a melting / mixing zone and an ultra-high temperature mixing zone, wherein the temperature of the ultra-high temperature mixing zone is 150.1°C to 180.0°C, alternatively 155°C to 174°C, alternatively 159°C to 172°C, alternatively 162°C to 171°C; feeding any one of materials (a) to (c) into the melting / mixing zone of the melt compounding device (e.g., an extruder): (a) a pellet / agent premix prepared by contacting solid pellets of an intermediate compound with one or more polyene-based crosslinking aids ("adjuvants"), these solid pellets initially comprising one or more thermoplastic polyolefins and one or more antioxidants, but lacking peroxides and polyene-based crosslinking aids; or (b) (c) a pellet / adjuvant / organic peroxide premix prepared by contacting solid pellets of an intermediate compound, which initially comprise one or more thermoplastic polyolefins and one or more antioxidants, but lack peroxides and polyene-based crosslinking aids, with a combination of curing agent additives, which comprises one or more polyene-based crosslinking aids ("adjuvants") and one or more organic peroxides ("organic peroxides"); or (d) solid pellets of an intermediate compound, which initially comprise one or more thermoplastic polyolefins and one or more antioxidants, but lack peroxides and polyene-based crosslinking aids. The method comprises the steps of: melting and mixing the one or more thermoplastic polyolefins with the other ingredients in materials (a), (b) or (c) for 15 to 35 seconds in the melting / mixing zone to obtain an initial molten mixture thereof; moving the initial molten mixture into an ultra-high temperature mixing zone of the melt compounding device (e.g., an extruder); optionally injecting one or more polyene-based crosslinking aids and / or one or more organic peroxides (collectively referred to as "curing agent additives") into the ultra-high temperature mixing zone; wherein if material (a) is fed, one or more organic peroxides are injected (not optional), and if material (c) is fed, one or more polyene-based crosslinking aids and / or one or more organic peroxides are injected (not optional); and material (a), (b) or (c) and any injected curing agent additives are mixed for a second time in the ultra-high temperature mixing zone for 10 to 20 seconds; and the resulting crosslinkable compound composition is discharged from the melt compounding device (e.g., an extruder); wherein material (a) (e.g., in. Figure 4 (b) (e.g. Figure 5 in) or material (c) (e.g. Figure 6 The total residence time of the melt compounding device (e.g., extruder) is 25 to 55 seconds, and the total residence time of any injected curing agent additive in the melt compounding device (e.g., extruder) is 10 to 30 seconds, alternatively 10 to 20 seconds. The injected curing agent additive will be directly injected into Figures 1 to 3 injection site (14) or injection Figures 4 to 6In some embodiments, the discharge step includes conveying the crosslinkable compound composition to a post-compounding device (e.g., a granulator or extruder or a system including a melt pump, a melt screen, and a granulator or extruder) as described below. The residence time in the melt compounding device does not include the residence time in the post-compounding device (if any). If used, the post-compounding device is different from the melt compounding device and is downstream of the melt compounding device.

[0015] The above method may include feeding and injecting material (a), including injecting the one or more organic peroxides and optionally one or more additional polyene-based crosslinking aids into the initial melt in the ultra-high temperature mixing zone of the melt compounding device (e.g., an extruder), and the second mixing step includes mixing material (a) and the injected curing agent additive. In some embodiments, the one or more additional polyene-based crosslinking aids are not injected. In other embodiments, at least one additional polyene-based crosslinking aid is injected. In this regard, Figure 4 In the description.

[0016] exist Figure 4 In the embodiment of the present invention, the melt compounding device 2 includes a melting and mixing zone 34, an ultra-high temperature mixing zone 37 and a discharge zone 38. The melt compounding device 2 may or may not be configured with an optional online pre-blender 32. The feed (a) 30 comprises at least one thermoplastic polyolefin (TPO) polymer, at least one polyene-based cross-linking aid, but does not comprise an organic peroxide. In one embodiment using an online pre-blender 32, the feed (a) 30 is fed 31 into the online pre-blender 32, pre-mixed therein, and the resulting pre-blender is fed 33a into the melting and mixing zone 34 of the melt compounding device 2. In another embodiment in which an online pre-blender 32 is not used, the feed (a) 30 is fed 33b directly into the melting and mixing zone 34 of the melt compounding device 2. The material passes through the melt compounding device 2 in a flow direction from left to right as shown by arrow 60. After processing in the melting and mixing zone 34 in either embodiment, the resulting material enters an ultra-high temperature mixing zone 37 while one or more organic peroxides 35 are injected 36 into the material passing through the ultra-high temperature mixing zone 37. Each of the one or more organic peroxides may be injected 36 individually or as a mixture thereof. After ultra-high temperature mixing according to the present invention, the resulting material containing the injected organic peroxides enters a discharge zone 38 and is then discharged 39 from the melt compounding device 2.

[0017] The one or more polyene-based crosslinking aids of material (a) include / do not include α-methylstyrene dimer (“AMSD”), because AMSD has only one alkenyl group per molecule, as shown in its structure:

[0018]

[0019] The above method (paragraph

[0015] ) may alternatively include an aspect where material (b) is fed without injection, and the second mixing step includes mixing material (b) without injecting additional curing agent additives therein. Figure 5 In the description.

[0020] exist Figure 5 In the embodiment of the present invention, the melt compounding device 2 includes a melting and mixing zone 34, an ultra-high temperature mixing zone 37 and a discharge zone 38. The melt compounding device 2 may or may not be configured with an optional online pre-blender 32. The feed (b) 40 comprises at least one thermoplastic polyolefin (TPO) polymer, at least one antioxidant, at least one polyene-based cross-linking aid and at least one organic peroxide. In one embodiment using an online pre-blender 32, the feed (b) 40 is fed 41 into the online pre-blender 22, pre-mixed therein, and the resulting pre-blended feed 43a is fed into the melting and mixing zone 34 of the melt compounding device 2. The feed passes through the melt compounding device 2 in a flow direction from left to right as shown by arrow 60. In another embodiment without using an online pre-blender 32, the feed (b) 40 is fed 43b directly into the melting and mixing zone 34 of the melt compounding device 2. After processing in the melting and mixing zone 34 in any embodiment, the resulting material enters the ultra-high temperature mixing zone 37, and optionally, if necessary, one or more additional additives 45 selected from one or more organic peroxides and / or one or more additional polyene-based crosslinking aids are simultaneously injected 46 into the material passing through the ultra-high temperature mixing zone 37. Each of the one or more additional organic peroxides (if any) and / or one or more additional polyene-based crosslinking aids (if any) can be injected 46 individually or as a mixture thereof, or when three or more are injected 46, some are injected individually and some are injected in the form of a mixture. After ultra-high temperature mixing according to the present invention, the resulting material optionally containing the injected additional additives enters the discharge zone 38 and is then discharged 39 from the melt compounding device 2.

[0021] In some embodiments, the one or more polyene-based crosslinking aids of material (b) are vinyl-D4, and the organic peroxide of material (b) is dicumyl peroxide.

[0022] The above method (paragraph

[0015] ) may include an aspect in which material (b) is fed and subjected to an injection step, and includes injecting one or more additional polyene-based crosslinking aids and / or one or more additional organic peroxides into the initial melt in the ultra-high temperature mixing zone of a melt compounding device (e.g., an extruder), and the second mixing step includes mixing material (b) and the injected curing agent additive. In some embodiments, at least one additional polyene-based crosslinking aid is injected, but no additional organic peroxide is injected. In other embodiments, at least one additional organic peroxide is injected, but no additional polyene-based crosslinking aid is injected. In other embodiments, at least one additional polyene-based crosslinking aid is injected and at least one additional organic peroxide is injected. This aspect is Figure 5 In some embodiments, the one or more polyene-based crosslinking aids of material (b) are vinyl-D4, and the organic peroxide of material (b) is dicumyl peroxide, and the injecting step includes injecting an additional polyene-based crosslinking aid, which is triallyl isocyanurate (TAIC).

[0023] The above method (paragraph

[0015] ) may include an aspect in which material (c) is fed, the method comprising feeding pellets of the intermediate compound into a melting / mixing zone of a melt compounding device (e.g., an extruder) to obtain a melt of the intermediate compound comprising the one or more thermoplastic polyolefins and the one or more antioxidants but lacking peroxides and polyene-based crosslinking aids, wherein the melt of the intermediate compound is at a melt temperature of 150.1°C to 180.0°C, alternatively 155°C to 174°C, alternatively 159°C to 172°C, alternatively 162°C to 171°C; injecting a combination of curing agent additives comprising the one or more organic peroxides and the one or more polyene-based crosslinking aids into the melt of the intermediate compound; and mixing the combination of curing agent additives into the melt of the intermediate compound to prepare a crosslinkable compound composition in melt form comprising a homogeneous mixture, wherein the homogeneous mixture is formed within 20 seconds to less than 60 seconds after completion of the injecting step. If the mixing step is terminated in less than 20 seconds, the mixture may not be completely homogeneous. If the mixing step is extended for more than 60 seconds, the homogeneous mixture may suffer from scorching. Figure 6 In the description.

[0024] exist Figure 6In the embodiment of the present invention, the melt compounding device 2 includes a melting and mixing zone 34, an ultra-high temperature mixing zone 37 and a discharge zone 38. The melt compounding device 2 may or may not be configured with an optional online pre-blender 32. The feed (c) 50 comprises at least one thermoplastic polyolefin (TPO) polymer, at least one antioxidant, but does not comprise a polyene-based cross-linking aid and does not comprise an organic peroxide. In one embodiment using an online pre-blender 32, the feed (c) 50 is fed 51 into the online pre-blender 32, pre-mixed therein, and the resulting pre-blender is fed 53a into the melting and mixing zone 34 of the melt compounding device 2. In another embodiment in which an online pre-blender 32 is not used, the feed (c) 50 is fed 53b directly into the melting and mixing zone 34 of the melt compounding device 2. The material passes through the melt compounding device 2 in a flow direction from left to right as shown by arrow 60. After processing in the melting and mixing zone 34 in either embodiment, the resulting material enters the ultra-high temperature mixing zone 37 while a combination 55 of curing agent additives comprising one or more organic peroxides and one or more polyene-based crosslinking aids is injected 56 into the material passing through the ultra-high temperature mixing zone 37. Each of the one or more organic peroxides and the one or more polyene-based crosslinking aids may be injected 56 individually or as a mixture thereof, or some may be injected individually and some may be injected as a mixture when three or more are injected 56. After ultra-high temperature mixing according to the present invention, the resulting material containing the injected combination 55 of curing agent additives enters the discharge zone 38 and is then discharged 39 from the melt compounding device 2.

[0025] The above method (paragraph

[0019] ) may include aspects applicable to a melt compounding apparatus, which may be a screw extruder, alternatively a single screw extruder or a twin screw extruder, which defines a conveying path therethrough and includes at least the following zones in series along the conveying path: a melting / compounding zone configured for heating the thermoplastic polyolefins to above their melting temperature and blending the antioxidant into the thermoplastic polyolefins and having a plurality of materials (e.g., comprising the thermoplastic polyolefins) for mixing the thermoplastic polyolefins with the antioxidant; one or more feed ports (also referred to as feed points) for feeding pellets of a thermoplastic polyolefin and an antioxidant or pellets containing a thermoplastic polyolefin without an antioxidant and a separate antioxidant source) into the melting / compounding zone (e.g., from an external hopper, an external feed line, or an external storage tank); a mixing zone configured for rapidly blending the curing agent additive into the polymer melt and having a material located between the melting / compounding zone and the mixing zone for injecting one or more materials containing the curing agent additive into the mixing zone (e.g., from an external storage tank or The method comprises: (A) providing a melt of an intermediate compound to a melting / compounding zone, or preparing a melt of an intermediate compound in a melting / compounding zone; (B) conveying the melt of the intermediate compound to a mixing zone; (C) injecting a combination of a curing agent additive comprising the one or more organic peroxides and the one or more polyene-based crosslinking aids into the melt of the intermediate compound through at least one of the one or more injection ports of the mixing zone; and (D) mixing the combination of the curing agent additive and the melt of the intermediate compound in the mixing zone to prepare a melt of a crosslinkable compound composition comprising a homogeneous mixture, wherein the homogeneous mixture is formed within 20.0 to 60.0 seconds after the injection step is completed; and (E) conveying the melt of the crosslinkable compound composition to the output zone.

[0026] The above method (paragraph

[0019] or paragraph

[0020] ) includes an aspect, which includes a post-output zone step suitable for a pelletizer equipped with a strand die (e.g., a multi-strand die), a cooling tool (e.g., a water bath) and a cutting device (e.g., a rotating blade), these post-output zone steps include conveying a melt of a crosslinkable compound composition from an output zone of a melt compounding device into a pelletizer; extruding strands of the crosslinkable compound composition; cooling the strands; and cutting the strands to prepare solid pellets of the crosslinkable compound composition.

[0027] The above method (paragraph

[0019] or paragraph

[0020] ) may include an aspect including post-output zone steps suitable for an insulation extruder equipped with an annular die for extruding coated filaments, the post-output zone steps including conveying a melt of a crosslinkable compound composition from an output zone of a melt compounding device to the insulation extruder; extruding a layer of the crosslinkable compound composition onto a conductor to prepare a coated conductor; and curing the crosslinkable compound composition of the insulation layer to prepare a cable. In some embodiments, the conductor includes one or more conductive wires, one or more light-transmitting glass fibers ("optical fibers"), or a combination thereof; and wherein the insulation layer comprises a crosslinked polyolefin product.

[0028] The above method (paragraphs

[0019] to

[0022] ) may include an aspect wherein the injecting step has limitation (i) or limitation (ii): (i) wherein the injecting step includes injecting the combination of curing agent additives together as a mixture thereof, or (ii) wherein the injecting step includes injecting at least one of the curing agent additives, alternatively all of the curing agent additives except one curing agent additive, alternatively each curing agent additive separately from the other curing agent additives.

[0029] The above method can include an aspect wherein the one or more thermoplastic polyolefins are selected for high temperature / low scorch manufacturing of the insulation layer of the cable at high production speeds and low scorch, wherein such one or more thermoplastic polyolefins have any of limitations (i) to (iii): (i) wherein there are one or more thermoplastic polyolefins, and at least one of the one or more thermoplastic polyolefins, alternatively each thermoplastic polyolefin is independently a low density polyethylene having a low density polyethylene having a molecular weight of 0.870 g / cm2 as measured according to ASTM D792 Method B; 3 Up to 0.940g / cm 3 and a melt index (I2) of 1 g / 10 min to 20 g / 10 min as determined at 190°C and 2.16 kg in accordance with ASTM D1238; or (ii) wherein there are one or more thermoplastic polyolefins and each thermoplastic polyolefin is independently selected from the group consisting of: a polyethylene homopolymer, an ethylene / 1-butene copolymer, an ethylene / 1-hexene copolymer, and an ethylene / 1-octene copolymer; or (iii) a combination of limits (i) and (ii).

[0030] The above method may include an aspect in which an additive is selected for high temperature / low scorch manufacturing of an insulation layer of a cable, wherein such additive has any one of limitations (i) to (v): (i) the one or more antioxidants include a sulfur-based antioxidant, alternatively a mixture of two or more sulfur-based antioxidants, alternatively two or more sulfur-based antioxidants comprising dodecyl thiodipropionate and stearyl thiodipropionate; or (ii) wherein the one or more polyene crosslinking aids include an alkenyl-containing monocyclic organosiloxane of formula (I): [R 1 ,R 2 SiO 2 / 2 ] n (I), wherein the subscript n is an integer greater than or equal to 3; each R 1 are independently (C2-C4)alkenyl or H2C═C(R 1a )—C(═O)—O—(CH2) m —, where R 1a is H or methyl, and the subscript m is an integer from 1 to 4; and each R 2 are independently H, (C1-C4) alkyl, phenyl or R 1 , alternatively 2,4,6,8-tetramethyl-2,4,6,8-tetravinyl-tetracyclosiloxane; or (iii) a combination of limitations (i) and (ii); (iv) wherein the one or more organic peroxides comprise dicumyl peroxide or a cumyl-containing peroxide, alternatively dicumyl peroxide; or (v) a combination of limitation (iv) with any one of limitations (i) to (iii).

[0031] The above method may include an aspect wherein the crosslinkable compound composition is formulated for high temperature / low scorch manufacturing of a crosslinkable insulation layer of a cable, wherein such crosslinkable compound composition has any one of limitations (i) to (iii): (i) the crosslinkable compound composition has: a scorch time at 140°C (ts1) of at least 63 minutes, alternatively at least 79 minutes, reported as the time required to increase by 1 pound-force-inch (lbf-in) or 1.13 deciNewton-meters (dN-m) from a minimum torque ("ML") at 140°C, as measured by a moving die rheometer (MDR) in accordance with ASTM procedure D5289. ) test; and a maximum torque at 182°C (MH) that is at least 1.67 deciNewton-meters (dN-m; equal to at least 1.48 lbf-in) higher than the minimum torque at 182°C (ML), alternatively MH is at least 1.72 dN-m higher than ML at 182°C (at least 1.52 lbf-in higher) and MH at 182°C is at least 1.79 dN-m (1.58 lbf-in), alternatively at least 1.83 dN-m (1.62 lbf-in), as determined by moving die rheometer (MDR) testing in accordance with ASTM procedure D5289; or (ii) the crosslinkable compound composition has a hot creep elongation at 200°C of less than 130%, alternatively less than 100%, as tested in accordance with ICEA T-28-562a; or (iii) the combination of limits (i) and (ii).

[0032] The above method can be further defined as follows.

[0033] If necessary, when feeding material (a) or material (b), the solid pellets can be premixed with the one or more polyene-based crosslinking aids of material (a) or the one or more polyene-based crosslinking aids of material (b) and one or more organic peroxides using a solid blender to obtain respective premixes, and then the premixes are fed into the melting / mixing zone of the extruder.

[0034] Without being bound by theory, it is believed that the inventive process produces a crosslinkable compound composition within the aforementioned temperature range and inherently having the aforementioned ts1 at 140°C and maximum torque (MH) at 182°C. This is evidence of the ultra-high temperature, low scorch, crosslinkability characteristics of the inventive process. Without being bound by theory, it is believed that the melt compounding temperature of 150.1°C to 180.0°C is unusually high for achieving these characteristics.

[0035] The process of the present invention of injecting and rapidly mixing (in less than 60 seconds) the organic peroxide and one or more polyene-based crosslinking aids into the melt stream of the intermediate compound rapidly provides a crosslinkable compound composition even before it cools from processing.

[0036] Without being bound by theory, we believe that in order to minimize the scorch of the crosslinkable compound composition, the method embodiment comprising feeding the material (a) containing the intermediate compound and one or more polyene-based crosslinking aids but not including the organic peroxide into the melting and mixing zone and later injecting the one or more organic peroxides into the ultra-high temperature mixing zone is superior to the method embodiment comprising feeding the material (c) containing the intermediate compound but not including any curing agent additive into the melting and mixing zone and later injecting all the curing agent additives into the ultra-high temperature mixing zone. This is because the polyene-based crosslinking aid can have the effect of inhibiting scorch, which is maximized by the former method embodiment of feeding the material (a) before the initial melt is injected with the organic peroxide and premixing the polyene-based crosslinking aid into the initial melt and the entire initial melt. In contrast, the latter method embodiment of feeding only the material (c) and later injecting the polyene-based crosslinking aid and the organic peroxide into the initial melt can have a portion that can contact with the organic peroxide before they contact the aid.

[0037] Also for similar reasons, we believe that the process embodiment comprising feeding material (b) comprising an intermediate compound and at least one polyene-based crosslinking aid and at least one organic peroxide into a melting and mixing zone, and later optionally injecting additional aids and / or additional organic peroxides into an ultra-high temperature mixing zone is also effective for preparing a crosslinkable compound composition and may be superior to the process embodiment comprising feeding material (c).

[0038] Therefore, since method embodiments including feeding material (c) may not be as effective in inhibiting scorching of the cross-linkable compound composition as method embodiments including feeding material (a) or material (b), we describe the former method embodiments and provide working examples that illustrate that those method embodiments work, and therefore the method embodiments including feeding material (a) or material (b) also work.

[0039] Injecting the curing agent additive during the melt compounding step does not require a melt cooling step or a post-compounding soaking step to prepare the crosslinkable compound composition. The method of the present invention consistently provides a fully formulated crosslinkable compound composition without the need for a melt cooling step or the need for soaking the thermoplastic polyolefin with a crosslinking initiator. The homogenous mixture prepared by this method contains fully incorporated organic peroxide and crosslinking aid only when the mixing step is completed. Unlike a comparative crosslinkable compound composition prepared by soaking the curing agent additive into pellets of an intermediate compound, it is not uniform, but may have a concentration gradient of the curing agent additive that is higher at the surface of the pellet and decreases toward the center of the pellet.

[0040] Providing step. The providing step may be applicable to pressurizing and / or melt screening the melt of the intermediate compound prior to the injecting step. In some embodiments of the method, such as described above, the method includes, prior to the injecting step and upstream of a mixing zone of a melt compounding device: pumping the melt of the intermediate compound through a first melt pump to prepare a pressurized melt stream of the intermediate compound; and melt screening the pressurized melt stream of the intermediate compound through a melt screen upstream of all of the one or more injection ports in the mixing zone of the melt compounding device, so as to melt screen the melt of the intermediate compound in the mixing zone.

[0041] The providing step may be applicable to controlling the overall melt temperature of the melt stream of the intermediate compound. These embodiments of the method may include adding a solid feed of a second polymer downstream of the primary solid feed of the thermoplastic polyolefin polymer (such as at any point upstream of each injection point or adjacent to the most upstream injection point), and melt compounding the second feed. Because the second polymer is in solid form, it is inherently at a temperature lower than the temperature of the melt stream of the intermediate compound. By introducing a controlled amount of the second polymer, such as a weight ratio of the second polymer feed to the initial polymer feed of 1:1 to 1:4, alternatively 1:2 to 1:4, the melt stream of the intermediate compound and the overall melt temperature of the resulting cross-linkable compound can be significantly reduced, and will not drop below a minimum of 150°C. The melt stream of the intermediate compound is at a temperature sufficient to melt the second polymer solid and achieve improved temperature control of the melt stream, that is, the melt temperature is reduced or maintained in the range of 150°C to 180°C.

[0042] Injection step. The injection step may be adapted for use with different types and arrangements of injection ports, and with or without melt screening. In some embodiments, the injection point for injecting the curing agent additive may include both of: (i) a distributive mixing or kneading zone at the downstream end of the melt compounding device; and (ii) an injection point downstream of melt formation in the melt compounding device itself; both of: (i) a distributive mixing or kneading zone at the downstream end of the melt compounding device; and (iii) downstream of a melt screen located downstream of the melt compounding device but upstream of a separate melt pump; (i) a distributive mixing or kneading zone at the downstream end of the melt compounding device; and (iv) upstream of a second melt pump located at a point downstream of both the separate melt pump and the melt screen in (iii); The following two: (ii) an injection point downstream of melt formation in the melt compounding device itself; and (iii) downstream of a melt screen located downstream of the melt compounding device but upstream of a separate melt pump; the following two: (ii) an injection point downstream of melt formation in the melt compounding device itself; and (iv) upstream of a second melt pump located at a point downstream of both the separate melt pump and the melt screen in (iii); or the following two: (iii) downstream of a melt screen located downstream of the melt compounding device but upstream of a separate melt pump; and (iv) upstream of a second melt pump located at a point downstream of both the separate melt pump and the melt screen in (iii). In some embodiments, the injection point for injecting the curing agent additive may include any three of injection points (i) to (iv), alternatively each of (i) to (iv).

[0043] The one or more injection points may be located downstream of a melt screen, which is itself located downstream of a melt pump. The melt compounding apparatus may include a dual melt pump arrangement, which also includes a second downstream melt pump and a melt screening apparatus located between the melt pump and the second downstream melt pump; the two melt pumps straddle the melt screen. In the dual melt pump version, injecting the combination of curing agent additives includes melt pumping a melt stream of the intermediate compound to prepare a pressurized melt stream, melt screening the pressurized melt stream of the intermediate compound, and injecting the combination of curing agent additives into the melt stream at an injection point downstream of the melt screen, which point may be in the second downstream melt pump or just upstream of the second downstream melt pump.

[0044] Mixing step. The mixing step is configured to quickly prepare a uniform mixture of the crosslinkable compound composition. This is achieved by continuing its melt compounding at the downstream end or downstream of the melt compounding device, immediately, quickly and fully (uniformly) blending the injected curing agent additive into the melt of the intermediate compound within 20 to 60 seconds. The method uses a melt compounding device described later, which is capable of operating at an ultra-high temperature of 150.1°C to 180.0°C and is capable of such rapid and thorough mixing in less than 60 seconds.

[0045] Devices that are not capable of rapid and thorough blending during the mixing step are excluded from the process. Such excluded devices include roll mills, tumblers, ball mills, handheld mixers, and any other long residence time mixing / blending devices, such as batch mixers, which are inherently incapable of thoroughly melting the thermoplastic polyolefin and mixing all ingredients of the crosslinkable compound composition in less than 60 seconds as described herein.

[0046] Continuous and batch processing embodiments of the method. The method is suitable for batch processing or continuous processing embodiments. As used herein, "batch processing" means an embodiment of the method in which the crosslinkable compound composition is prepared intermittently at discrete short intervals, for example, every few minutes or every few hours depending on the size of the equipment, and / or interrupting the flow of materials through the production line, so as to prepare intermediate materials and final products at discrete times and in discrete batches.

[0047] "Continuous processing" means an embodiment of a method in which a crosslinkable compound composition is constantly prepared without any time interruption or interruption of the flow of materials through the production line so as to produce the final product without interruption. In theory, a continuous process can run forever, but in practice runs for 12 hours or more, alternatively 24 hours or more, alternatively 7 days or more, and can be stopped infrequently, such as to clean the equipment, when the supply of raw materials is interrupted (e.g., due to transportation delays), or to change equipment to prepare a different final product. The continuous embodiment produces the crosslinkable compound composition as a continuous stream in a few seconds at a production rate that is beneficially high enough (e.g., at least 10 kilograms of crosslinkable compound composition are prepared per hour (kg / hour), alternatively at least 50 kg / hour, alternatively at least 100 kg / hour) to continuously feed the freshly prepared crosslinkable compound composition into a granulation device or a cable coating device in a commercial cable production line. In some embodiments, the method is a continuous method of a continuous embodiment comprising a providing step, an injecting step, and a mixing step.

[0048] Optional Additional Steps of the Method. The method is not particularly limited to include additional steps, provided that any additional steps do not invalidate the providing step, the injecting step, and the mixing step.

[0049] Optional preparatory steps before providing steps. In order to prepare the intermediate compound in uniform form and continuous method, the primary feed of thermoplastic polyolefin polymer and one or more antioxidants can be melt compounded or melt blended in a melt compounding device to prepare the primary melt stream of the intermediate compound. Usually in practice, the method includes the step of melting the thermoplastic polyolefin polymer. But it is also envisioned that other embodiments of the melt (that is, not generated from a solid) of the thermoplastic polyolefin polymer are directly generated, such as the polymerization reaction of polymerizing olefin monomers in a solution and / or at a temperature higher than the melt temperature of the polymer. In some embodiments, the method includes at least one of the following additional steps: before providing the step, the intermediate compound in solid form (such as pellets) is introduced into the melting / compounding zone through a feed port in the melting / compounding zone and the step of melting the introduced intermediate compound in the melting / compounding zone of the screw extruder. Alternatively, before the providing step, one or more thermoplastic polyolefins in solid form are introduced through a feed port in the melting / compounding zone and the one or more antioxidants are introduced into the melting / compounding zone and the one or more thermoplastic polyolefins are melted in the melting / compounding zone of the screw extruder, and the one or more antioxidants are melt-compounded into the melt of the one or more thermoplastic polyolefins to prepare a melt of the intermediate compound. The melt of the one or more thermoplastic polyolefins or the melt of the intermediate compound may be melt-screened before the providing step.

[0050] Optional steps after the mixing step. The method is not particularly limited to including additional steps, provided that any additional steps do not invalidate the providing step, the injecting step, and the mixing step. For example, the method does not allow any step that delays the mixing step for more than 60 seconds or prevents the mixing step from achieving mixture uniformity. In some embodiments, the method does not include any steps before the providing step, while in other embodiments, the method includes at least one additional step before the providing step, such as a step of preparing a melt of the intermediate compound. In some embodiments, the method does not include any steps after the mixing step, while in other embodiments, the method includes at least one additional step after the mixing step, such as a granulation step or a coating step. In some embodiments, the method does not include any steps between the providing step and the injecting step, while in other embodiments, the method includes at least one step between the providing step and the mixing step, such as a step of feeding a second polymer into the melt of the intermediate compound. The method does not include any steps between the injecting step and the mixing step, but may include additional steps during the injecting step, such as injecting one or more non-curing agent additives while injecting a combination of curing agent additives.

[0051] In some embodiments, the method includes one or more additional steps after the mixing step, which are suitable for preparing the insulation layer (commonly referred to as "insulated conductor") of the power cable or telecommunication cable. The insulated conductor generally comprises a conductor covered by an insulating layer. The conductor may be solid or stranded (e.g., a bundle of wires). Some insulated electrical conductors may also contain one or more additional elements, such as one or more semiconducting layers and / or protective sheaths (e.g., windings, tapes, or sheaths). Examples are coated metal wires and power cables, including metal wires and power cables for low voltage ("LV", >0 kilovolts to <5 kilovolts (kV)), medium voltage ("MV", 5kV to <69kV), high voltage ("HV", 69kV to 230kV) and extra high voltage ("EHV", >230kV) power cables and their power transmission / distribution applications.

[0052] Melt Screening and Pressurizing Steps. Any process step that employs a polymer melt may be suitable for melt screening and / or pressurizing. Apparatus that may be used for such melt screening and / or pressurizing is described below.

[0053] Melt compounding units and optional equipment for production lines.

[0054] The method can be successfully carried out in any device capable of performing the providing step, the injecting step and the mixing step. An example of such a device is the melt compounding device described above. Some embodiments of the method may include one or more additional devices selected from the group consisting of: a melt pump, a melt screen (e.g., a filtration unit containing a melt screen) and a granulator device. In some embodiments, the method may also include a coating device for applying the crosslinkable compound composition to a wire or optical fiber, such as in the manufacture of a power cable or a communication cable.

[0055] Suitable devices for preparing a homogeneous mixture of the intermediate compound and the crosslinkable compound composition may include a distributive mixing device or section in an extruder, or a high intensity mixer, such as a mixing rotor, toothed mixing elements (TME, ZME, etc.), and a kneading block, such as a kneading block (forward, neutral or reverse pumping), a gear mixer, a melt pump, a gear pump, or a bubble element, when coupled with a downstream mixing element. Such melt compounding devices may include, for example, a co-rotating intermeshing twin-screw extruder (e.g., a 30 millimeter (mm) inner diameter Coperion ZSK-30 twin-screw extruder, used later in working examples CE1 and IE1 to IE4; or a 26 mm inner diameter Coperion ZSK-26 twin-screw extruder, which may be used in future working examples), a counter-rotating, high intensity, non-intermeshing twin-rotor mixer (e.g., Farrel, FCM), or a single screw extruder equipped with an appropriate mixing device (e.g., a Maddock mixing section (which includes a Maddock mixing device)). If the process of the present invention includes delivering a melt stream of the intermediate compound to a melt pump and melt screening the pressurized melt stream upstream of any injection point (i.e., where the combination of curing agent additives is injected into the melt stream), a wider selection of compounding devices can be used. In this case, the melt compounding device can include any of the compounders listed above, co-rotating intermeshing twin screw extruders, or counter-rotating high-intensity non-intermeshing twin screw compounding mixers. If the curing agent is not sufficiently quickly and thoroughly incorporated into the melt by the above means, the resulting composition will experience severe scorching or organic peroxide decomposition. For example, experiments on a comparative Banbury mixer discharged at a melt temperature of 155°C and adding a combination of curing agent additives downstream resulted in severe scorching, making the compound unusable.

[0056] Pressure is required to push the melt through the screen in the screening step, or through the die in the pelletizing step. Some melt compounding devices that can be used in aspects of the method generate enough pressure to perform screening or pelletizing (i.e., they are "generate sufficient pressure"). Other melt compounding devices that can be used in aspects of the method do not generate enough pressure for screening and / or pelletizing (i.e., they generate insufficient pressure), and in these aspects, a melt pump or a single screw extruder can also be used to generate enough pressure. Therefore, the melt compounding device can, but does not have to, generate enough pressure for melt screening or pelletizing.

[0057] Examples of melt compounding devices that generate sufficient pressure for screening or granulation are single screw extruders and some twin screw extruders. Examples of melt compounding devices that cannot generate sufficient pressure for screening or granulation and are therefore used in combination with a melt pump or single screw extruder are some twin screw extruders, co-rotating intermeshing twin screw extruders that are not configured to generate sufficient pressure for melt screening or granulation, and counter-rotating high-intensity non-intermeshing twin screw extruders (e.g., Farrel FCM and LCM, Kobe Steel LCM, Japan Steel Works (JSW) continuous intensive mixer (CIM) or CIMP), or a single screw extruder equipped with an appropriate mixing device (e.g., Maddock mixing zone).

[0058] Suitable production lines include at least one melt compounding device moving from upstream to downstream in the melt stream, and also include a distributive mixing element (i) in the melt compounding device, such as a gear mixer or gear mixing element, or (ii) as a melt pump located downstream of the melt compounding device, or (iii) both, and further include a melt screening unit. The melt mixing device may also include a granulator or a granulation die. The melt mixing device may include two melt pumps, one located upstream of the melt screen and the other located downstream of the melt screen.

[0059] Suitable melt screening devices for use in the process of the present invention according to the present invention may include, for example, continuous screening or filtering technology, such as continuous plates, rotating screen converters, sliding plate screen converters, double bolt or chamber screen converters or any candle, pleated candle, disc, cylinder or flat plate filter element having a woven or non-woven filter medium capable of stopping particles in the size range of 25 μm to 500 μm (such as, for example, polymer gels).

[0060] Suitable melt pumps for use in the process of the present invention may include any melt pump known in the art, such as a MAAG, Farrel-Pomini, gear mixer, or a melt pump appropriately modified to enhance mixing twin gear pressure generation.

[0061] In the example of an extruder, a single screw or twin screw extruder has a feeder, a melt screw zone and a downstream mixing zone, such as a kneading block or a gear mixer. The thermoplastic polyolefin polymer feed consisting of LDPE and an antioxidant can be fed via the feeder at the upstream end of the extruder barrel; the curing agent additive can be injected at any of the various injection sites upstream of the downstream mixing zone.

[0062] Description of the drawings. Figure 1 , Figure 2 and Figure 3 The types of melt compounding apparatus and production lines that can be used in embodiments of the process are described. Figure 4, Figure 5 and Figure 6 It is described that material (a) ( Figure 4 )、Material (b) Figure 5 ) or material (c)( Figure 6 ) is fed into the melting / mixing zone of a melt compounding device (e.g., an extruder).

[0063] Figure 1 The method and apparatus of the present invention for preparing a conductor or cable insulation composition are depicted. The melt compounding line (2) includes, from upstream to downstream and from left to right, a melt compounding device (4) (in this case a twin screw extruder), a melt pump (6), a melt screen (8) and a pelletizing die (10). The melt compounding device (4) melts and mixes a base thermoplastic polyolefin (ethylene polymer) feed (12), including any antioxidant additives, and optionally contains a combination of curing agent additives. The melt pump (6) helps to build up pressure upstream of the melt screen (8), which itself promotes the distribution of the curing agent additive and improves the cleanliness of the cross-linkable compound product. The pelletizing die (10) pelletizes the formulation into a ready-to-use form. The melt compounding device (4) can be a twin screw extruder, a counter-rotating twin rotor mixer (e.g., Farrel, FCM) or a single screw extruder. Along the melt compounding line (2), the curing agent additive can be injected at any injection point (14), including: i) injection into the melt compounding device (4) at or above the distribution mixing zone (not shown); ii) the transition between the melt compounding device (4) and the melt pump (6); or iii) directly into the melt pump (6), or a combination thereof. Multiple injection points (14) can be used to inject the required total amount of curing agent additive, each injection point containing a portion of the combination of curing agent additives.

[0064] Figure 2Other inventive methods and apparatus for preparing conductor or cable insulation compositions are depicted. The melt compounding line (2) comprises, from upstream to downstream and from left to right, a melt compounding device (4) (in this case a twin screw extruder), two melt pumps (6) across a melt screen (8), and a pelletizing die (10). The melt compounding device (4) melts and mixes a base thermoplastic polyolefin (ethylene polymer) feed (12), including an antioxidant additive, and optionally also a combination of curing agent additives. The upstream (left-hand) melt pump (6) helps to build pressure upstream of the melt screen (8), which itself improves the cleanliness of the cross-linkable compound product. The downstream (right-hand) melt pump (6) disperses the curing agent additive into the intermediate compound. The pelletizing die (10) pelletizes the formulation into a ready-to-use form. The melt compounding device (4) can be a co-rotating intermeshing twin screw extruder, a counter-rotating twin screw compounding mixer (e.g., Farrel, FCM), or a single screw extruder. The curing agent additive can be injected into one or more injection sites (14), which include i) a transition line between the melt screen (8) and the downstream melt pump (6); or ii) directly into the downstream melt pump (6). Two injection locations (14) can be used so that multiple injectors (not shown) can inject an amount of curing agent additive totaling the desired amount.

[0065] Figure 3 An experimental melt compounding production line (2) used in some examples is shown and includes, from upstream to downstream and from left to right, an extruder (20), a polymer feeding point (12), an injection point for a combination of curing agent additives (14), a melt screen (8) and a pelletizing die (10).

[0066] Figure 4 A process flow diagram illustrating an embodiment of a method of feeding material (a) into a melting / mixing zone of a melt compounding device (e.g., an extruder). Figure 4 In the method, material (a) includes at least one thermoplastic polyolefin polymer ("TPO polymer"), at least one antioxidant, at least one polyene-based crosslinking aid ("adjuvant"), but does not include peroxide. Material (a) is continuously fed into the melting and mixing zone of the extruder, whereby the TPO polymer is continuously and rapidly melted as described above to obtain an initial melt. The initial melt is continuously conveyed to an ultra-high temperature mixing zone ("ultra-high temperature mixing zone"), where it continuously receives an injection of one or more organic peroxides. The one or more organic peroxides are quickly and fully mixed into the initial melt to prepare a melt of a crosslinkable compound composition, which is discharged from the melt compounding device. Figure 4 It is envisaged that the crosslinkable compound composition is discharged into a post-compounding device (eg, a granulator) not shown.

[0067] Figure 5 A process flow diagram illustrating an embodiment of a method of feeding material (b) into a melting / mixing zone of a melt compounding device (e.g., an extruder). Figure 5 In the method, material (b) includes at least one thermoplastic polyolefin polymer ("TPO polymer"), at least one antioxidant, at least one polyene-based crosslinking aid ("adjuvant"), and at least one organic oxide. Material (b) is continuously fed into the melting and mixing zone of the extruder, whereby the TPO polymer is continuously and rapidly melted as described above to obtain an initial melt. The initial melt is continuously conveyed to an ultra-high temperature mixing zone ("ultra-high temperature mixing zone"), where it does not receive any injection of curing agent additives, or it continuously receives injection of at least one additional organic peroxide, at least one additional polyene-based crosslinking aid, or both. Any injected additional organic peroxide and / or adjuvant is quickly and fully mixed into the initial melt to prepare a melt of a crosslinkable compound composition, which is discharged from the melt compounding device. Figure 5 It is envisaged that the crosslinkable compound composition is discharged into a post-compounding device (eg, a granulator) not shown.

[0068] Figure 6 A process flow diagram illustrating an embodiment of a method of feeding material (c) into a melting / mixing zone of a melt compounding device (e.g., an extruder). Figure 6 In the embodiment of the present invention, material (c) includes at least one thermoplastic polyolefin polymer ("TPO polymer") and at least one antioxidant, but does not include any polyene-based crosslinking aid ("adjuvant") or peroxide. Material (c) is continuously fed into the melting and mixing zone of the extruder, whereby the TPO polymer is continuously and rapidly melted as described above to obtain an initial melt. The initial melt is continuously conveyed to an ultra-high temperature mixing zone ("ultra-high temperature mixing zone"), in which it continuously receives an injection of a curing agent additive comprising one or more polyene-based crosslinking aids and one or more organic peroxides. The curing agent additive can be injected as a premix thereof or injected separately and separately. The injected curing agent additive is quickly and fully mixed into the initial melt to prepare a melt of the crosslinkable compound composition, which is discharged from the melt compounding device. Figure 6 It is envisaged that the crosslinkable compound composition is discharged into a post-compounding device (eg, a granulator) not shown.

[0069] Extruded articles. The crosslinkable compound composition prepared by the method can be extruded into articles. These extruded articles include pellets, coatings, films, laminates, tubes, conduits, etc. containing the crosslinkable compound composition. The extruded articles may include any polyolefin-based layer of a coated conductor, including a semiconducting layer (containing carbon black), an insulating layer, or both. The extruded articles may experience high temperatures when in use, such as due to the heating that the insulating layer will experience during operation of a MV, HV, or EHV power cable.

[0070] Crosslinkable compound compositions. The crosslinkable compound compositions are inventive in the manner in which they are prepared by the inventive method, which can produce an inherent difference in at least one property compared to an otherwise identical comparative compound composition made from the same ingredients in the same amounts, but by any passive method of incorporating the one or more organic peroxides into the thermoplastic polyolefin. Examples of such passive methods are immersion and absorption. In some embodiments, the passive methods cannot achieve the properties of the present invention.

[0071] For example, the thermal history of the crosslinkable compound composition of the present invention differs from the thermal history of the comparative compound composition due to their different preparation methods. Therefore, due to the different thermal history, the crosslinkable compound composition of the present invention may differ from the comparative compound composition in at least one aspect selected from the group consisting of: the ratio of each component; the concentration of each component; melt rheological properties; and mechanical properties.

[0072] The crosslinkable compound composition is storage stable. This enables separate in-line article fabrication at a later time, ie separate extrusion and shaping into articles, such as cable insulation. The batch is stable or even crosslinkable after melt compounding.

[0073] The crosslinkable compound composition is scorch resistant and has excellent curing properties. In some embodiments, the method and the composition prepared thereby have any one of limitations (i) to (iii): (i) the scorch time (scorch time) ts1 at 140°C is at least 95 minutes; (ii) the minimum torque (ML) at 182°C is 0.10 to 0.14 deciNewton-meters (dN-m); or (iii) a combination of limitations (i) and (ii). In some embodiments, the crosslinkable compound composition has a scorch time (ts1) at 140°C of at least 63 minutes, alternatively at least 79 minutes, which is reported as the time required to increase from the minimum torque ("ML") at 140°C by 1 pound-force-inch (lbf-in) or 1.13 deciNewton-meters (dN-m), as determined by moving die rheometer (MDR) testing in accordance with ASTM procedure D5289; and the crosslinkable compound composition has a minimum torque (ML) at 182°C of at least 63 minutes, alternatively at least 79 minutes. The crosslinkable compound composition preferably has a maximum torque (MH) at 182° C. of at least 1.67 deciNewton-meters (dN-m; equal to at least 1.48 lbf-in) less, alternatively MH is at least 1.72 dN-m (at least 1.52 lbf-in) higher than ML at 182° C. and MH at 182° C. is at least 1.79 dN-m (1.58 lbf-in), alternatively at least 1.83 dN-m (1.62 lbf-in), as determined by moving die rheometer (MDR) testing according to ASTM procedure D5289. If the scorch time (ts1) of the crosslinkable compound composition is too low (i.e., less than 63 minutes), the crosslinkable compound composition may experience too much scorch and may not be of sufficient quality for making extruded articles. The longer the measured value of the scorch time (ts1) exceeds 63 minutes, the less premature crosslinking of the crosslinkable compound composition. If the MH of the crosslinkable compound composition at 182° C. is too low (i.e., less than 1.6 dN-m), the crosslinkable compound composition may not be curable or may have defects such as gel. If the MH of the crosslinkable compound composition at 182° C. is too high (i.e., greater than 4 dN-m), the crosslinkable compound composition may take too long to be completely cured.

[0074] The crosslinkable compound composition has excellent extrudability, as shown by its rheological properties. In some embodiments, the method and the composition prepared thereby have any one of the limitations (i) to (iii): (i) a melt index I at 120°C, 10.0 kg 10(ii) a viscosity at a shear rate of 0.1 rad / sec at 135°C of 1.7 kilopascal-second to 2.7 kilopascal-second (kPa-sec) (1,700 Pa-sec to 2,700 Pa-sec); or (iii) a combination of limits (i) and (ii). If the crosslinkable compound composition has a viscosity at 120°C of 1 10 If the viscosity at 135°C / 0.1 rad / sec is too low (i.e., less than 4 g / 10 min or less than 1.7 kPa-sec, respectively), the crosslinkable compound composition may not have sufficient melt extrudability, resulting in defects such as cracks, voids or gels in the extruded article. 10 Or if the viscosity at 135°C / 0.1rad / sec is too high (i.e., less than 6 g / 10 min or greater than 2.7 kPa-sec, respectively), an extruded article made from its cross-linked product may not have sufficient creep resistance when exposed to heat. In some embodiments, the viscosity of the cross-linkable compound composition at 135°C / 0.1rad / sec is 2.05 kPa-sec to 2.65 kPa-sec.

[0075] The crosslinkable compound composition has excellent mechanical properties, as shown in at least one of its tensile strength, tensile resistance and thermal creep resistance. In some embodiments, the method and the composition prepared therefrom have any one of limitations (i) to (v): (i) tensile strength greater than 17.20 megapascals (MPa); (ii) elongation at break greater than 500.0%; (iii) a combination of limitations (i) and (ii); (iv) thermal creep at 200°C less than 80.0%; or (v) a combination of limitation (iv) and any one of limitations (i) to (iii). If the tensile strength and / or elongation at break are too low, the extruded article made from its crosslinked product may have insufficient mechanical strength for its intended use. If the tensile strength and / or elongation at break are too high, the extruded article made from its crosslinked product may break prematurely during use. If the thermal creep of the crosslinkable compound composition at 200°C is too high (i.e., greater than 80%), the extruded article made from its crosslinked product may not have sufficient creep resistance when exposed to heat.

[0076] Intermediate compounds and melts thereof, including primary streams.

[0077] The intermediate compound is suitable for use in the method. For example, the one or more thermoplastic polyolefins (TPOs) are selected to have a sufficiently high total initial melt index value (I2) so that after the mixing step, even if the crosslinkable compound composition has undergone minimal premature crosslinking (scorching), it also has a melt rheology that enables the composition to be subsequently extruded into an extruded article. For example, in some embodiments, the one or more thermoplastic polyolefins have a total melt index (I2) determined at 190°C and 2.16kg according to ASTM D1238 of 1g / 10 minutes to 20g / 10 minutes, alternatively 2g / 10 minutes to 10g / 10 minutes, alternatively 3g / 10 minutes to 10g / 10 minutes, alternatively 3g / 10 minutes to 5g / 10 minutes. If the total I2 of the one or more TPOs is too low (i.e., less than 1g / 10 minutes), the crosslinkable compound composition may not have sufficient melt extrudability after minimal scorching, resulting in defects in the extruded article, such as cracks, voids or gels. If the total I2 of the one or more TPOs is too high (ie, greater than 20 g / 10 min), extruded articles made from the crosslinked products thereof may not have adequate creep resistance when exposed to heat.

[0078] The intermediate compound can be prepared by any method or sequence of steps, and how the intermediate compound is prepared is not particularly important for the method. In some embodiments of the method, such as described above, prior to the providing step: (a1) one or more antioxidants and the one or more thermoplastic polyolefins are fed into the melting / compounding zone via the one or more feed ports to prepare a primary stream containing the one or more antioxidants and the one or more thermoplastic polyolefins (collectively referred to as the ingredients of the primary stream) but lacking peroxide and polyene-based crosslinking aids and any added second polymer solids; (a2) melt compounding the primary stream at a temperature of 155° C. to 174° C. in the melting / compounding zone to prepare a melt of the intermediate compound; (a3) ​​cooling the melt of the intermediate compound to produce the intermediate compound in solid form (e.g., in the form of pellets); and (a4) feeding the solid form of the intermediate compound into the melting / compounding zone of the screw extruder.

[0079] In some embodiments using the above-described melt compounding apparatus, the one or more thermoplastic polyolefins and the one or more antioxidants, but lacking peroxides and polyene-based crosslinking aids and any added second polymer solids, are referred to herein as "primary streams". Primary streams containing the one or more antioxidants and the one or more thermoplastic polyolefins (collectively referred to as components of primary streams) but lacking one or more curing agent additives selected from the group consisting of organic peroxides and polyene-based crosslinking aids, and intermediate compounds prepared therefrom (the intermediate compounds comprising a mixture of one or more thermoplastic polyolefin polymers and one or more antioxidants (AO), but lacking one or more curing agent additives) do not contain any other polymers. In such embodiments, the polymer components of the primary stream and the intermediate compounds prepared therefrom consist of one or more thermoplastic polyolefins. In such embodiments, the polymer component of the crosslinkable compound composition prepared by the method of the present invention consists of one or more thermoplastic polyolefins, and the polymer component of the crosslinked compound composition prepared by curing the crosslinkable compound composition independently consists of one or more thermoplastic polyolefins and / or crosslinked polyolefins prepared by curing the one or more thermoplastic polyolefins.

[0080] In some embodiments, the primary stream containing the one or more antioxidants and the one or more thermoplastic polyolefins (collectively referred to as the components of the primary stream) but lacking one or more curing agent additives selected from the group consisting of organic peroxides and polyene crosslinking aids, and the melt stream of the intermediate compound prepared therefrom (the intermediate compound comprising a mixture of one or more thermoplastic polyolefin polymers and one or more antioxidants (AO), but lacking one or more curing agent additives), also contains a polyolefin, which is a non-thermoplastic polymer as described above. In such embodiments, the polymer components of the primary stream and the intermediate compound prepared therefrom consist of one or more thermoplastic polyolefins and one or more ethylene / unsaturated carboxylic acid ester copolymers. Based on the total weight of the primary stream, the proportion of one or more ethylene / unsaturated carboxylic acid ester copolymers in such embodiments used for the primary stream can be 0.05% to 20% by weight, alternatively 0.10% to 15% by weight, alternatively 0.10% to 5% by weight, and based on the total weight of the intermediate compound, the proportion of one or more ethylene / unsaturated carboxylic acid ester copolymers in such embodiments used for the intermediate compound can independently be 0.05% to 20% by weight, alternatively 0.10% to 15% by weight, alternatively 0.10% to 5% by weight. Embodiments of the crosslinkable compound composition prepared therefrom according to the process of the present invention also contain one or more ethylene / unsaturated carboxylic acid ester copolymers, and the crosslinked compound composition prepared by curing such embodiments contains crosslinked products thereof.

[0081] Thermoplastic polyolefin (TPO). The crosslinkable compound composition includes a thermoplastic polyolefin ("TPO"). As used herein, the terms "thermoplastic polyolefin" and "TPO" refer to homopolymers prepared by polymerizing a single unsaturated hydrocarbon monomer and copolymers prepared by polymerizing two or more different unsaturated hydrocarbon monomers, each of which consists of carbon atoms and hydrogen atoms.

[0082] In some embodiments, the thermoplastic polyolefin is an ethylene-based polymer. The ethylene-based polymer comprises 51 wt % to 100 wt % of ethylene units derived from ethylene polymerization and 49 wt % to 0 wt % of copolymerized units derived from one, alternatively two olefin functional monomers (monomers and comonomers) polymerization. The comonomers may be selected from propylene, (C4-C 20 )α-olefins and 1,3-butadiene. (C4-C 20 The α-olefin may be a (C4-C8) α-olefin such as 1-butene, 1-hexene or 1-octene.

[0083] The ethylene-based polymer embodiments of the TPO may be selected from polyethylene homopolymers, ethylene / propylene copolymers, and ethylene / (C4-C 20 )α-olefin copolymers. Examples of unsaturated hydrocarbon monomers are ethylene; propylene; (C4-C 20 )α-olefins; and 1,3-butadiene. In some embodiments, the TPO is a polyethylene homopolymer or an ethylene / (C4-C 20 )α-olefin copolymer. (C4-C 20 )α-olefins are of the formula H2C=C(H)-(CH2) q CH3 compounds, wherein the subscript q is an integer from 1 to 17. In some embodiments, (C4-C 20 ) the α-olefin is 1-butene, 1-hexene or 1-octene; alternatively 1-butene or 1-hexene; alternatively 1-octene; alternatively 1-hexene; alternatively 1-butene.

[0084] If blends of ethylene polymers are employed, the polymers may be blended by any in-reactor or post-reactor method.

[0085] The ethylene polymer may be selected from the group consisting of low density polyethylene ("LDPE"), linear low density polyethylene ("LLDPE"), very low density polyethylene ("VLDPE"), and combinations of two or more thereof. LDPE is typically a highly branched ethylene homopolymer and can be prepared by a high pressure process (i.e., HP-LDPE).

[0086] Suitable LDPE may have a range from 0.91 g / cm3 Up to 0.94g / cm 3 or for example at least 0.915 g / cm 3 But less than 0.94g / cm 3 , or less than 0.93g / cm 3 The density of the polymers provided herein is determined according to ASTM method D792. The LDPE suitable for use herein may have a melt index (I2) of 1 g / 10 min to 20 g / 10 min, alternatively 2 g / 10 min to 10 g / 10 min, alternatively 3 g / 10 min to 10 g / 10 min, alternatively 3 g / 10 min to 5 g / 10 min, determined according to ASTM method D1238 at 190°C and 2.16 kg.

[0087] Suitable LLDPE may have a heterogeneous distribution of comonomers (e.g., α-olefin monomers) and be characterized by short chain branching. For example, LLDPE may be a copolymer of ethylene and α-olefin monomers with a density in the range of 0.916 / cm 3 Up to 0.925g / cm 3 LLDPE suitable for use herein may have the same melt index (I2) as LDPE.

[0088] VLDPE and ULDPE suitable for use as TPO may have a heterogeneous distribution of comonomers (e.g., α-olefin monomers) and may be characterized by short chain branching. For example, the VLDPE may be a copolymer of ethylene and α-olefin monomers, such as one or more of those α-olefin monomers described above. VLDPE suitable for use herein may have a molecular weight of 0.87 to 0.915 g / cm 3 The VLDPE suitable for use herein may have the same melt index (I2) as that of LDPE.

[0089] The total weight of the one or more thermoplastic polyolefins in the intermediate compound and / or crosslinkable compound composition may be 50 wt % to 99.79 wt %, alternatively 80.0 wt % to 99.79 wt %, alternatively 95 wt % to 99 wt %, for example 98.0 wt % to 98.9 wt %, all weights based on the total weight of the intermediate compound or crosslinkable compound composition, respectively. Any weight % that cannot be attributed to the one or more thermoplastic polyolefins, the one or more antioxidants and curing agent additives may be attributed to one or more non-curing agent additives described later and / or the second polymer described herein.

[0090] Thermoplastic polyolefins can be made by methods known in the art. Any conventional or later discovered production process for producing suitable ethylene polymers can be used to prepare ethylene-based polymer embodiments of thermoplastic polyolefins. Generally speaking, polymerization can be achieved under conditions known in the art for Ziegler-Natta or Kaminsky-Sinn polymerization, that is, at a temperature of 0°C to 250°C or 30°C or 200°C and at a pressure of 100 atmospheres to 10,000 atmospheres (1,013 megapascals ("MPa")), alternatively 500 atmospheres to 10,000 atmospheres. In most polymerization reactions, the molar ratio of polymerization catalyst to monomer ranges from 10 to 10. -12 :1 to 10 -1 :1 or 10 -9 :1 to 10 -5 :1.

[0091] Polyolefins that are not thermoplastic are not included as embodiments of the one or more thermoplastic polyolefins, but can be included in certain embodiments of the intermediate compound and the crosslinkable compound composition prepared therefrom as additional components of non-thermoplastic polymers. The example of such non-thermoplastic polymers is ethylene / unsaturated carboxylic acid ester copolymers. The example of usable ethylene / unsaturated carboxylic acid ester copolymers is ethylene / alkyl acrylate (EAA) copolymer, ethylene / alkyl methacrylate (EAMA) copolymer and ethylene / vinyl acetate (EVA) copolymer. The example of ethylene / alkyl acrylate copolymers is ethylene / methyl acrylate (EMA) copolymer, ethylene / ethyl acrylate (EEA) copolymer and ethylene / butyl acrylate (EBA) copolymer. The example of ethylene / alkyl methacrylate copolymers is ethylene / methyl methacrylate (EMMA) copolymer, ethylene / ethyl methacrylate (EEMA) copolymer and ethylene / butyl methacrylate (EBMA) copolymer. In the embodiments including these polymers, these polymers can be used as the second polymer.

[0092] Antioxidants. The intermediate compound contains one or more antioxidants. Suitable antioxidants (AO) may include tertiary amines, secondary or tertiary thiols, secondary or tertiary phenols, bisphenols, triphenols and tetraphenols, alternatively combinations of two or more of these. Examples of suitable antioxidants may include, for example, (4-(1-methyl-1-phenylethyl)phenyl)amine (e.g., NAUGARD 445, Addivant USA, Danbury, CT); 2,2-methylene-bis(4-methyl-6-tert-butylphenol) (e.g., VANOX MBPC, Vanderbilt Chemicals, New York, NY); 2,2'-thiobis(2-tert-butyl-5-methyl)phenol (CAS No. 90-66-4); 4,4'-thiobis(2-tert-butyl-5-methylphenol) (also known as 4,4'-thiobis(6-tert-butyl-m-cresol), CAS No. 96-69-5, LOWINOX TBM 6 antioxidant, Addivant); 2,2'-thiobis(6-tert-butyl-4-methylphenol) (CAS No. 90-66-4, commercially available as LOWINOX TBP-6); tris[(4-tert-butyl-3-hydroxy-2,6-dimethylphenyl)methyl)-1,3,5-triazine-2,4,6-trione (e.g., CYANOX 1790 antioxidant, Solvay Chemicals, Syracuse, NY); pentaerythritol tetrakis(3-(3,5-bis(1,1-dimethylethyl)-4-hydroxyphenyl)propionate (e.g., IRGANOX 1010 antioxidant, CAS No. 6683-19-8); 2,2'-thiodiethyl 3,5-bis(1,1-dimethylethyl)-4-hydroxyphenylpropionate (e.g., IRGANOX 1035 antioxidant, CAS No. 41484-35-9, BASF, Ludwigshafen, DE); distearyl thiodipropionate (DSTDP); dilauryl thiodipropionate (e.g., IRGANOX PS 800 antioxidant); stearyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate (e.g., IRGANOX 1076); 2,4-bis(dodecylthiomethyl)-6-methylphenol (IRGANOX 1726 antioxidant); 4,6-bis(octylthiomethyl)-o-cresol (e.g., IRGANOX 1520 antioxidant); and 2,3-bis[[3-[3,5-di-tert-butyl-4-hydroxyphenyl]propionyl]]propionohydrazide (IRGANOX 1024 antioxidant).In some embodiments, the one or more antioxidants include 4,4'-thiobis(2-tert-butyl-5-methylphenol), also known as 4,4-thiobis(6-tert-butyl-m-cresol); 2,2'-thiobis(6-tert-butyl-4-methylphenol); tris[(4-tert-butyl-3-hydroxy-2,6-dimethylphenyl)methyl]-1,3,5-triazine-2,4,6-trione; distearyl thiodipropionate or didodecyl thiodipropionate (e.g., Cyanox 2212); or a combination of any two or more thereof. In some embodiments, the antioxidant may be a combination of tris[(4-tert-butyl-3-hydroxy-2,6-dimethylphenyl)methyl)-1,3,5-triazine-2,4,6-trione and distearyl thiodipropionate. The total amount of the one or more antioxidants may be 0.01 wt % to 5 wt %, or 0.05 wt % to 3 wt %, or 0.10 wt % to 0.30 wt %, all weights based on the total weight of the intermediate compound or crosslinkable compound composition, respectively.

[0093] Organic peroxide. The curing agent additive includes the one or more organic peroxides. As used herein, the organic peroxide is: a molecule containing carbon atoms, hydrogen atoms and two or more oxygen atoms and having at least one -OO- group, provided that when more than one -OO- group is present, each -OO- group is indirectly bonded to another -OO- group via one or more carbon atoms; or a collection of such molecules. The curing agent additive may include one or more organic peroxides, and the one or more organic peroxides may independently be of formula R O -OOR O A monoperoxide, where each R O Independently (C1-C 20 )alkyl or (C6-C 20 ) aryl. Each (C1-C 20 ) alkyl groups are independently unsubstituted or substituted with 1 or 2 (C6-C 12 ) aryl group. Each (C6-C 20 ) aryl groups are unsubstituted or substituted with 1 to 4 (C1-C 10 Alternatively, the curing agent additive may include one or more organic peroxides, which may be of formula R O -OOROOR O A diperoxide wherein R is a divalent hydrocarbon group such as (C2-C 10 ) alkylene, (C3-C 10 ) cycloalkylene or phenylene, and each R OAs defined above. Alternatively, the curing agent additive may comprise one or more monoperoxides and one or more diperoxides. Examples of suitable organic peroxides are bis(1,1-dimethylethyl)peroxide; bis(1,1-dimethylpropyl)peroxide; 2,5-dimethyl-2,5-bis(1,1-dimethylethylperoxy)hexane; 2,5-dimethyl-2,5-bis(1,1-dimethylethylperoxy)hexyne; 4,4-bis(1,1-dimethylethylperoxy)pentanoic acid; butyl ester; 1,1-bis(1,1-dimethylethylperoxy)-3,3,5-trimethylcyclohexane; benzoyl peroxide; tert-butyl peroxybenzoate; di-tert-amyl peroxide ( "DTAP"); bis(α-tert-butylperoxyisopropyl)benzene ("BIPB"); isopropylcumyl tert-butyl peroxide; tert-butylcumyl peroxide; di-tert-butyl peroxide; 2,5-bis(tert-butylperoxy)-2,5-dimethylhexane; 2,5-bis(tert-butylperoxy)-2,5-dimethylhexyne-3,1,1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane; isopropylcumylcumyl peroxide; butyl 4,4-di(tert-butylperoxy)valerate; or di(isopropylcumyl) peroxide; or dicumyl peroxide. In some embodiments, the organic peroxide comprises or consists of dicumyl peroxide. In some aspects, a blend of two or more organic peroxides is used, for example, a 20:80 (weight / weight) blend of tert-butylcumyl peroxide and bis(tert-butylperoxyisopropyl)benzene (e.g., LUPEROX D446B, which is commercially available from Arkema). The total amount of the one or more organic peroxides can be 0.1 wt % to 5 wt %, or 0.2 wt % to 3 wt %, or 0.3 wt % to 0.8 wt %, all weights based on the total weight of the intermediate compound or the crosslinkable compound composition, respectively.

[0094] Polyene-based crosslinking aid. The curing agent additive comprises one or more polyene-based crosslinking aids. Suitable polyene-based crosslinking aids may include, for example, monocyclic organosiloxanes of formula (I): [R 1 ,R 2 SiO 2 / 2 ] n (I), wherein the subscript n is an integer greater than or equal to 3; each R 1 are independently (C2-C4)alkenyl or H2C═C(R 1a )—C(═O)—O—(CH2) m —, where R 1a is H or methyl, and the subscript m is an integer from 1 to 4; and each R 2 are independently H, (C1-C4) alkyl, phenyl or 1The same. Suitable polyene crosslinking aids of formula (I) include, for example, 2,4,6-trimethyl-2,4,6-trivinyl-cyclotrisiloxane ("vinyl-D3"), 2,4,6,8-tetramethyl-2,4,6,8-tetravinyl-cyclotetrasiloxane ("vinyl-D4"), 2,4,6,8,10-pentamethyl-2,4,6,8,10-pentavinyl-cyclopentasiloxane ("vinyl-D5") and mixtures thereof. Other suitable polyene crosslinking aids may include bifunctional monomers and higher functional monomers copolymerizable with ethylene polymers, such as polyallyl or polyvinyl crosslinking aids. As used herein, "polyallyl" refers to a compound having at least two pendant allyl functional groups, for example, a triallyl compound selected from the group consisting of triallyl isocyanurate ("TAIC"), triallyl cyanurate ("TAC"), triallyl trimellitate ("TATM"), and mixtures of two or more thereof. Examples of suitable polyallyl crosslinking aids include polyallyl crosslinking aids such as triallyl isocyanurate ("TAIC"), triallyl cyanurate ("TAC"), triallyl trimellitate ("TATM"), triallyl orthoformate, triallyl pentaerythritol ether, triallyl citrate, and triallyl aconitate; polyacrylate crosslinking aids such as ethoxylated bisphenol A dimethacrylate; trimethylolpropane triacrylate ("TMPTA"), trimethylolpropane trimethyl methacrylate ("TMPTMA"), 1,6-hexanediol diacrylate, pentaerythritol tetraacrylate, dipentaerythritol pentaacrylate, tris(2-hydroxyethyl)isocyanurate triacrylate, and propoxylated glycerol triacrylate; polybutadiene with a high 1,2-vinyl content, and trivinylcyclohexane ("TVCH"); and other polyene-based crosslinking aids as described in U.S. Pat. Nos. 5,346,961 and 4,018,852. Other polyene-based crosslinking aids may have at least one N,N-diallylamide functional group, such as disclosed in U.S. Pat. No. 10,941,278B2 to Cai et al. The polyene-based crosslinking aid may be TAIC. Other examples of polyene-based crosslinking aids are described in US Pat. No. 6,277,925 (eg, allyl 2-allyl-phenyl ether, etc.) and US Pat. No. 6,143,822 (eg, 1,1-diphenylethylene, which may be unsubstituted or substituted).

[0095] The polyene-based crosslinking aid can be a blend of two or more such aids. In some embodiments, the polyene-based crosslinking aid is a blend of a monocyclic organosiloxane of formula (I) and a polyallyl crosslinking aid. In some embodiments, the polyene-based crosslinking aid is a blend of 2,4,6,8-tetramethyl-2,4,6,8-tetravinyl-cyclotetrasiloxane (vinyl-D4) and triallyl isocyanurate (TAIC).

[0096] The amount of the one or more polyene crosslinking aids in the intermediate compound and / or crosslinkable compound composition may be 0.1 wt % to 10 wt %, alternatively 0.3 wt % to 5 wt %, alternatively 0.6 wt % to 3 wt %, alternatively 1.1 wt % to 2.4 wt %, all based on the total weight of the intermediate compound or crosslinkable compound composition, respectively.

[0097] In some embodiments, the combination of the curing agent additive comprises an organic peroxide and one or two polyene-based crosslinking aids. In some embodiments, the method uses the following substances and the crosslinkable compound composition comprises the following substances: low-density polyethylene (LDPE); at least one antioxidant selected from distearyl thiodipropionate and didodecyl thiodipropionate; at least one organic peroxide selected from dicumyl peroxide; and at least one polyene-based crosslinking aid selected from 2,4,6,8-tetramethyl-2,4,6,8-tetravinyl-cyclotetrasiloxane (vinyl-D4) and triallyl isocyanurate (TAIC).

[0098] Optional non-curing agent additives. In some embodiments, the intermediate compound and the crosslinkable compound composition contain one or more additional non-curing agent additives in addition to the one or more antioxidants. The one or more additional non-curing agent additives can be additives known to be used in the insulating layer of power cables or telecommunication cables. Examples of such one or more additional non-curing agent additives are hindered amine stabilizers (HAS), such as hindered amine light stabilizers (HALS), inorganic fillers; flame retardants; anti-tree agents; methyl radical scavengers; processing aids; colorants; slip agents; plasticizers; surfactants; extender oils; scavengers; metal deactivators; or any combination of two or more thereof.

[0099] Any compound, composition, formulation, material, mixture or reaction product herein may be free of any one of the chemical elements selected from the group consisting of Li, Be, B, N, O, F, Na, Mg, Al, Si, P, S, Cl, K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, As, Se, Br, Rb, Sr, Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag, Cd, In, Sn, Sb, Te, I, Cs, Ba, Hf, Ta, W, Re, Os, Ir, Pt, Au, Hg, Tl, Pb, Bi, lanthanides and actinides; provided that the chemical elements inherently required thereby are not omitted.

[0100] Alternatively, before different embodiments. ANSI is the American National Standards Institute organization headquartered in Washington, DC, USA. ASME is the American Society of Mechanical Engineers headquartered in New York City, New York, USA. ASTM is a standards organization, ASTM International, West Conshohocken, Pennsylvania, USA. Any comparative example is for illustrative purposes only and should not be prior art. Containing or lacking means completely absent; alternatively undetectable. IEC is the International Electrotechnical Commission, 3 rue de Varemb, Case postale 131, CH-1211, Geneva 20, Switzerland, http: / / www.iec.ch. IUPAC is the International Union of Pure and Applied Chemistry (IUPAC Secretariat, Research Triangle Park, North Carolina, USA). The periodic table is the IUPAC version published on May 1, 2018. Permitted options may be given, but not essential. Operability means functionally capable or effective. Optional (ground) means the absence (or exclusion) of alternative presence (or inclusion). Properties can be measured using standard test methods and conditions. Ranges include endpoints, subranges, and integers and / or fractional values ​​contained therein, except for integer ranges that do not include fractional values. Room temperature: 23°C ± 1°C.

[0101] Unless otherwise indicated, the definitions of terms used herein are taken from the "IUPAC Compendium of Chemical Technology" ("Gold Book"), version 2.3.3, February 24, 2014.

[0102] Any one or more of the open-ended terms "comprising" or "comprises" may be replaced with the partially closed phrase "consisting essentially of" or "consists essentially of" or replaced with the closed phrase "consisting of" or "consists of". As used herein, the phrase "consisting essentially of" or "consists essentially of" means that the process, the intermediate compound, and the cross-linkable compound composition do not contain any excluded elements and steps. Examples of excluded steps are passively adding a curing agent additive to the intermediate compound just before the injection step and cooling the melt of the intermediate compound to less than 150°C. In some embodiments, non-continuous production processes are not included. Excluded elements include excluded devices such as soaking towers or excluded mixing devices and any excluded additives, such as those found in the unexpected prediction prior art. The phrases "consisting of and consists of" are closed and exclude any elements or features not expressly listed thereafter. The terms "comprising" or "including" used in reference to subsequent materials or features do not negate the partially closed nature of "consisting essentially of" or "consists essentially of," or the closed nature of "consisting of" or "consists of," but only allow for any additional elements or steps not expressly excluded by "consisting essentially of" or "consists of." A prophetic example is an embodiment of the invention that has not yet been actually made but is contemplated by the inventors to function in accordance with the invention.

[0103] Any range formed by combining a preferred lower limit with any upper limit, or by combining a preferred upper limit with any lower limit, or by combining a measured value from any of the inventive examples with any lower or upper limit is contemplated herein.

[0104] Preparation of cured panels: Using WABASH with quench cooling capability TM GENESIS TM Steam press to compact and solidify the pellets. For comparative compound compositions, a WABASH with quench cooling capability was used. TM GENESISTM The soaked pellets were pressed and cured in a steam press (Wabash MPI, Wabash, IN). The panels were then subjected to the specified tests. Curing for thermal creep testing involved pressing the pellets in a compression mold (Wabash MPI, Wabash, IN). TM GENESIS TM The sample was melted at 120°C for 3 minutes at a low pressure of 3.5 MPa (500 psi) in a steam press; the size of the mold was 203 mm × 203 mm (8 inches × 8 inches) × 1.3 mm (50 mils), and then pressed at a high pressure of 17 MPa (2500 psi) for another 3 minutes at the same temperature; the mold was opened, the plate was removed from the mold and cut into four pieces of similar size. In the test, the four pieces were then rearranged, put back into the mold, melted at 120°C for 3 minutes at a low pressure of 3.5 MPa (500 psi), and pressed at a high pressure of 17 MPa (2500 psi) for another 3 minutes at the same temperature; the temperature of the press was then raised to 182°C and maintained for 12 minutes to cure the sample at the high pressure. After curing, the mold was cooled to room temperature at 15°C / minute at the high pressure.

[0105] Preparation of uncured panels: Using a Wabash with quench cooling capability TM GENESIS TM Steam press pressed the soaked pellets. For the following moving die rheometer test method, the pellets were first melted at 120°C for 3 minutes at a low pressure of 3.5 MPa (500 psi) and pressed at a high pressure of 17 MPa (2500 psi) at the same temperature for another 3 minutes. The mold was cooled to room temperature at 15°C / min at the high pressure to form an uncured plate.

[0106] Density test method: measured according to ASTM D792-13, "Standard Test Methods for Density and Specific Gravity (Relative Density) of Plastics by Displacement, Method B", (used to test solid plastics in liquids other than water, such as in liquid 2-propanol). The unit is g / cm3 (g / cm 3 ).

[0107] Melt index (I2) test method: According to ASTM D1238-04 (190°C, 2.16kg), Standard Test Method for Melt Flow Rates of Thermoplastics by Extrusion Platometer, I2 is measured using the conditions of 190°C / 2.16 kilograms (kg). The unit is grams eluted per 10 minutes (g / 10min) or equivalent to decigrams per 1.0 minute (dg / 1min), where 10.0dg=1.00g.

[0108] Melt index (I 10 ) Test method: According to ASTM D1238-04 (120°C, 10.0 kg), standard test method for determining the melt flow rate of thermoplastics using an extrusion planimeter, using the conditions of 120°C / 10.0 kg (kg) to measure I 10 The unit is g / 10min or equivalently dg / 1min, where 10.0dg=1.00g.

[0109] Stability Test Method: Samples of each crosslinkable compound composition prepared by the process of the present invention were collected under the same processing conditions and at various time intervals after the start of injection of the curing agent additive into the melt stream of the intermediate compound and tested to demonstrate product and process stability as shown by the consistency of product properties produced over long continuous melt compounding runs. To demonstrate the ability of the process of the present invention to operate as a continuous, high product output process, experiments were conducted as long continuous melt compounding runs lasting 2 to 4 hours.

[0110] Thermal creep test method: Thermal creep measures the cure properties or degree of crosslinking of a crosslinkable compound; it may also indicate the extent to which a compound has not yet crosslinked. Thermal creep refers to the elongation deformation of a cured sample of a given crosslinkable compound under load and is measured according to ICEA T-28-562. Thermal creep testing is performed at 200°C with a load of 20 N / cm 2 The weight is attached to the lower end of a 1.3 mm (50 mil) dog bone sample, which is cut from a cured plate using a die cutter according to ASTM D412 Type D and marked with two reference lines, each at a distance of 25.4 mm from the middle of the sample. The samples are placed in a preheated oven at 200°C, and a weight equal to 20 N / cm is attached to the bottom of each sample. 2The weights were applied to the sample with a force applied. After 15 minutes, the elongation (distance between the reference lines) was measured and used to calculate thermal creep. The weights were removed from the sample. After 5 minutes in the oven, the sample was removed and left at room temperature for 24 hours. The elongation (distance between the reference lines) was measured again and this value was used to calculate thermal set. Three samples were tested and the average value for thermal creep is reported. An acceptable thermal creep result is 100% or less. For thermal creep, the lower the elongation %, the more cross-linked the material is.

[0111] Moving Die Rheometer (MDR) Test Method: The moving die rheometer (MDR) is capable of measuring the curing characteristics of crosslinkable compounds. The instrument measures the torque response of the material under deformation. When the material undergoes crosslinking, the torque response increases and eventually reaches a maximum torque ("MH") after the peroxide has reacted under the test conditions of time and temperature. The MH value represents the crosslinking level of a given compound and should be high enough to produce a crosslinkable compound. According to ASTM procedure D5289 "Standard Test 20 Method for Rubber-Property Vulcanization Using Rotorless Cure Meters", an Alpha Technologies rheometer MDR model 2000 unit (Alpha Technologies, Hudson, OH) is used to measure under shear and perform MDR testing. For testing, a 2.56 cm (1 inch) diameter circle is cut from an uncured plate of 1.905 mm (75 mils) (thickness), and 2 1.905 mm (75 mils) circles are stacked together. Two 1.905 mm (75 mil) circles stacked were tested at 182°C for 12 minutes to obtain MH, and at 140°C (typical extrusion melt temperature) for varying lengths of time to obtain ts1. Both tests were conducted under 0.5 degree arc oscillation. MH is reported as the torque value when the curve levels off. Ideally, MH is above 2.26 dN-m or <2 lbf-in after processing and does not change with time.

[0112] The scorch time or ts1 indication is a cure kinetic that can be used to evaluate resistance to premature crosslinking (scorch). For the scorch time measurement, the reported value is the time required to increase the minimum torque ("ML") by 1 unit (inch-pounds) or 1.13 decimal Newton-meters (dN-m). An acceptable ts1 at 140°C should be at least 51 minutes or longer. The longer the ts1, the better. Other scorch metrics such as ts0.5, ts2, ts5, etc. may be used with equivalent definitions.

[0113] Tensile Strength and Elongation at Break Test Method: Measured on 75 mil thick two-pass compression molded plaques cured at 182°C using a pull speed of 50.8 cm (20 in) / min and a load of 45.3 kg (100 lbs).

[0114] Viscosity Test Method: (Oscillatory Shear Viscosity Test at Low Shear Rate of 0.1 rad / sec): Constant temperature frequency sweeps were performed under nitrogen purge using a TA Instruments "Advanced Rheological Extension System (ARES)" equipped with 25 mm (diameter) parallel plates. The sample was placed on the plate and allowed to melt at 135°C for five minutes. The plate was then brought close to a gap set to "1.5 mm", the sample was trimmed (extra sample extending beyond the periphery of the "25 mm diameter" plate was removed), and then the test was started. A five-minute delay was additionally built into the method to allow temperature equilibrium. The test was performed at 135°C over a frequency range of 0.1 rad / sec (rad / s) to 100 rad / s at a constant strain amplitude of 25%.

[0115] Example

[0116] Low density polyethylene (LDPE-1) LDPE-1 has a density of 0.919 g / cm 3 A thermoplastic polyolefin having a melt index I2 of 3.9 g / 10 min. Available from Dow Chemical Company as AGILITY TM EC 7000 was obtained.

[0117] Antioxidant Blend 1: Combination of Lauryl Thiodipropionate and Stearyl Thiodipropionate. Available as Cyanox 2212 from Solvay Chemicals.

[0118] Organic peroxide example: dicumyl peroxide ("DiCup" or "DCP") having the structure PhC(CH3)2-OOC(CH3)2Ph, wherein Ph is phenyl.

[0119] Crosslinking Aid Example 1: Triallyl isocyanurate ("TAIC").

[0120] Crosslinking aid example 2: 2,4,6,8-tetramethyl-2,4,6,8-tetravinyl-cyclotetrasiloxane ("vinyl-D4").

[0121] The same amounts of the above compounds (LDPE-1, Antioxidant Blend 1, DiCup, TAIC, and Vinyl-D4) were used in the following Comparative Example 1 and Inventive Examples 1 to 4, except that the process used to prepare CE1 was the comparative soaking process described below, and the process for preparing IE1 to IE4 included an embodiment of the inventive process. The amounts are shown in Table 1 below.

[0122] Table 1: Amounts of compounds used in CE1 and IE1 to IE4 :

[0123] Element Type of compound Amount (weight %) LDPE-1 Thermoplastic Polyolefin (TPO) 98.20 Antioxidant Blend 1 Combination of two sulfo-antioxidants 0.15 DiCup Organic peroxide 0.50 TAIC Crosslinking aid 0.30 Vinyl-D4 Crosslinking aid 0.85 total Crosslinkable compound composition 100.00

[0124] Preparation of intermediate compound 1: composed of pellets of LDPE-1 and antioxidant blend 1 in relative amounts shown in Table 1. Pellets were prepared by melt compounding LDPE-1 and antioxidant blend 1 in a twin-screw extruder, followed by pelletizing using a Conair 304 strand pelletizer to obtain intermediate compound 1.

[0125] Comparative Example 1 (CE1): CE1 prepared by a comparative soaking method, the comparative soaking method comprising preheating 250 grams of pellets of intermediate compound 1 at 70°C for at least 4 hours to obtain preheated pellets; adding a liquid mixture of DiCup, TAIC and vinyl-D4 to the preheated pellets in the relative amounts shown in Table 1 to obtain a combination of the preheated pellets and the liquid mixture; tumbling the combination to evenly distribute the liquid mixture onto the preheated pellets; and heating the tumbled pellet / liquid combination at 70°C overnight (at least 12 hours) to obtain Comparative Example 1 in the form of soaked pellets consisting of intermediate compound 1, DiCup, TAIC and vinyl-D4. The comparative crosslinkable compound composition of CE1 was tested according to the above test method, and the data is later recorded in Table 3.

[0126] Line Example 1: The process of the present invention for running Inventive Examples 1 to 4 (IE1 to IE4): Melt Compounding Apparatus and Post-Compounding Apparatus. The melt compounding apparatus is a 30 millimeter (mm) inner diameter Coperion ZSK-30 twin screw extruder defining a conveying path therethrough and including at least the following zones in series along the conveying path: a melting / compounding zone configured for heating the thermoplastic polyolefins to above their melting temperature and blending the antioxidant into the thermoplastic polyolefins and having a feed system for feeding one or more materials (e.g., pellets comprising the thermoplastic polyolefin and the antioxidant or pellets comprising the thermoplastic polyolefin without the antioxidant and a separate antioxidant source) into the melting / compounding zone (e.g., from an external hopper, an external feed line, or an external storage tank). The invention relates to a melt compounding device, a melt compounding device, a melt screen, a granulator or an extruder, and a system including a melt pump, a melt screen and a granulator or an extruder. The melt compounding device is a melt pump, a melt screen (installed in a filtration unit), and a granulator including a granulation die.

[0127] Inventive Examples 1 to 4 (IE1 to IE4): IE1 to IE4 were prepared using the above-described Line Example 1 and the inventive process processing conditions shown in Table 2 below.

[0128] Table 2: Processing conditions for IE1 to IE4 .

[0129]

[0130] *rpm = revolutions per minute; **melt temperature measured with a handheld probe; ***The data reported in Table 3 are the average of 1 sample each of IE1, IE3 and IE4 and 3 samples of IE2, where the 3 samples of IE2 were taken approximately 1 hour apart.

[0131] As shown in Table 2, a homogeneous mixture of the crosslinkable polymer composition of the present invention was prepared in less than 60 seconds. Samples of the crosslinkable polymer composition were tested according to the above test methods. The data are reported in Table 3 below.

[0132] Table 3: Properties of crosslinkable compound compositions of CE1 and IE1-IE4

[0133]

[0134] In Table 3, the data reported for IE2 is the average of three test samples taken approximately 1 hour apart during continuous operation. The individual hot creep data for the IE2 samples are 121% (2bk), 110% (1bk), and 102% (1bk), where 2bk means two of the three samples broke and 1bk means one of the three samples broke. STDEV means standard deviation. N / a means not applicable.

[0135] The data in Table 3 show that using the comparative soaking method, CE1, which was not modified via a high temperature compounding step, exhibited a melt index I of 6.0 g / 10 min. 10 (120°C, 10.0 kg) and an ML at 182°C of 0.1 lbf-in, which is low and indicates no premature scorch. IE1 to IE4 are prepared via embodiments of the ultra-high temperature, low scorch melt compounding process of the present invention and exhibit lower melt index I 10 Values, indicating that the rheology of the thermoplastic polyolefin (LDPE-1 in the example) changes due to some initial decomposition of the organic peroxide (DiCup in the example) during the ultra-high temperature compounding step, and the resulting crosslinkable compound composition of the present invention still maintains a combination of appropriate levels of curing agent additives (DiCup, TAIC and vinyl-D4 in the example) and exhibits sufficient levels of crosslinking, as shown by its MH value at 182°C. The MH values ​​of IE1 to IE4 at 182°C are surprisingly approximately the same as the MH value of the comparative soaked crosslinkable compound composition of CE1 at 182°C. The results of the oscillatory shear viscosity test at a low shear rate of 0.1 rad / sec are also shown in Table 3. Available upon request is the relaxation spectrum data.

[0136] The above detailed description teaches the method of the present invention, and the results of IE1 to IE4 demonstrate that the method and its benefits are achieved.

[0137] Table 4: Amounts of compounds used in CE2 (actual) .

[0138] Element Type of compound Amount (weight %) LDPE-1 Thermoplastic Polyolefin (TPO) 99.85 Antioxidant Blend 1 Combination of two sulfo-antioxidants 0.15 DiCup Organic peroxide 1.4 TAIC Crosslinking aid 0.00 Vinyl-D4 Crosslinking aid 0.00 AMSD Anti-scorch agent 0.35 total Crosslinkable compound composition 100.00

[0139] Table 5: Amounts of compounds used in Inventive Example 5 .

[0140] Element Type of compound Amount (weight %) LDPE-1 Thermoplastic Polyolefin (TPO) 99.85 Antioxidant Blend 1 Combination of two sulfo-antioxidants 0.15 DiCup Organic peroxide 1.4 TAIC Crosslinking aid 0.50 Vinyl-D4 Crosslinking aid 0.00 AMSD Anti-scorch agent 0.00 total Crosslinkable compound composition 100.00

[0141] Table 6: Amounts of compounds used in Inventive Example 6 .

[0142] Element Type of compound Amount (weight %) LDPE-1 Thermoplastic Polyolefin (TPO) 99.85 Antioxidant Blend 1 Combination of two sulfo-antioxidants 0.15 DiCup Organic peroxide 1.4 TAIC Crosslinking aid 0.00 Vinyl-D4 Crosslinking aid 0.50 AMSD Anti-scorch agent 0.00 total Crosslinkable compound composition 100.00

[0143] Comparative Example 2 (actual) and Inventive Examples 5 and 6 (IE5 and IE6) (prophetic): prepared using the inventive process processing conditions shown in Line Example 1 and Table 2.

[0144] Table 7: Actual properties of the crosslinkable compound composition of CE2 and the crosslinkable compound compositions of IE5 and IE6 Expected properties. Data in brackets ("[]") indicate predicted values, e.g. TS1 of

[100] at 140°C indicates a predicted 100 minutes .

[0145]

[0146] As shown in Table 7, as expected, the scorch retarder AMSD provides CE2 with a scorch time TS1 at 140°C of greater than 120 minutes (>120 minutes). However, because AMSD has only one carbon-carbon double bond per molecule, it is not a polyene-based crosslinking aid and cannot function as a polyene-based crosslinking aid. Therefore, even though CE2 is prepared via an embodiment of the ultra-high temperature, low-scorch melt compounding process of the present invention, it does not show inventive improvements, but has inferior MH and MH-ML at 182°C, inferior hot creep at 200°C, inferior tensile strength, and inferior elongation at break. CE2 shows that the comparative process without using a polyene-based crosslinking aid cannot achieve inventive improvements.

[0147] Compared to Table 7, if IE5 and IE6 were to be produced via an embodiment of the ultra-high temperature, low scorch melt compounding process of the present invention, they would be expected to exhibit a lower melt index I 10 IE5 and IE6 show that embodiments of the method in which the combination of curing agent additives comprises one or more organic peroxides and only one polyene-based crosslinking aid are expected to show inventive improvements.

Claims

1. An ultra-high temperature, low scorch method for preparing a crosslinkable compound composition, the crosslinkable compound composition comprising a uniform mixture of one or more thermoplastic polyolefins, one or more antioxidants and a combination of curing agent additives, the combination of curing agent additives comprising one or more organic peroxides and one or more polyene-based crosslinking aids, the method comprising: Providing a melt compounding device, the melt compounding device sequentially having a solid conveying zone, a melting / mixing zone and an ultra-high temperature mixing zone, wherein the temperature of the ultra-high temperature mixing zone is 150.1° C. to 180.0° C.; Feed any one of materials (a) to (c) into the melt / Mixing zone: (a) a pellet / auxiliary agent premix prepared by contacting solid pellets of an intermediate compound, the solid pellets initially comprising one or more thermoplastic polyolefins and one or more antioxidants, but lacking peroxides and polyene-based crosslinking aids ("auxiliaries"); or (b) a pellet / auxiliary agent / organic peroxide premix prepared by contacting solid pellets of an intermediate compound, the solid pellets initially comprising one or more thermoplastic polyolefins and one or more antioxidants, but lacking peroxides and polyene-based crosslinking aids, the combination of curing agent additives comprising one or more polyene-based crosslinking aids ("auxiliaries") and one or more organic peroxides ("organic peroxides"); or (c) solid pellets of an intermediate compound, the solid pellets initially comprising one or more thermoplastic polyolefins and one or more antioxidants, but lacking peroxides and polyene-based crosslinking aids, wherein material (c) lacks curing agent additives; Melting and first mixing the one or more thermoplastic polyolefins with the other ingredients of the material (a), (b) or (c) in the melting / mixing zone for 15 seconds to 35 seconds to obtain an initial molten mixture thereof; moving the initial molten mixture into the ultra-high temperature mixing zone of the melt compounding device; Optionally injecting one or more polyene-based crosslinking aids and / or one or more organic peroxides (collectively referred to as "curing agent additives") into the initial melt in the ultra-high temperature mixing zone, wherein if the material (a) is fed, the injection of one or more organic peroxides is performed (not optional), and if the material (c) is fed, the injection of one or more polyene-based crosslinking aids and / or one or more organic peroxides is performed (not optional); as well as mixing the material (a), (b) or (c) and any injected curing agent additive for a second time in the ultra-high temperature mixing zone for 10 seconds to 20 seconds; as well as discharging the obtained crosslinkable compound composition from the melt compounding device; wherein the total residence time of the material (a), the material (b) or the material (c) in the melt compounding device is from 25 seconds to 55 seconds, and wherein the total residence time of any injected curing agent additive in the melt compounding device is from 10 seconds to 30 seconds.

2. The method according to claim 1, wherein feeding the material (a) and performing the injection comprises injecting the one or more organic peroxides and optionally one or more additional polyene-based crosslinking aids into the initial melt in the ultra-high temperature mixing zone of the melt compounding device, and the second mixing step comprises mixing the material (a) and the injected curing agent additive.

3. The method of claim 1, wherein the material (b) is fed without the injecting, and the second mixing step comprises mixing the material (b) without injecting an additional curing agent additive.

4. The method according to claim 1, wherein the material (b) is fed and subjected to an injection step, and comprises injecting one or more additional polyene-based crosslinking aids and / or one or more additional organic peroxides into the initial melt in the ultra-high temperature mixing zone of the melt compounding device, and the second mixing step comprises mixing the material (b) and the injected curing agent additive.

5. The method of claim 1, wherein the material (c) is fed, the method comprising feeding the pellets of the intermediate compound into the melting / mixing zone of the melt compounding device to obtain a melt of the intermediate compound comprising the one or more thermoplastic polyolefins and the one or more antioxidants but lacking peroxides and polyene-based crosslinking aids, wherein the melt of the intermediate compound is at a melt temperature of 150.1° C. to 180.0° C.; injecting the combination of the curing agent additive comprising the one or more organic peroxides and the one or more polyene-based crosslinking aids into the melt of the intermediate compound; as well as The combination of curing agent additives is mixed into the melt of the intermediate compound to prepare the crosslinkable compound composition in melt form comprising the homogeneous mixture, wherein the homogeneous mixture is formed within 20 seconds to less than 60 seconds after the injecting step is completed.

6. The method of claim 5, said method being applied to a melt compounding device defining a conveying path therethrough and including in series along said conveying path at least the following zones: a melting / compounding zone configured for heating thermoplastic polyolefins to above their melt temperature and blending antioxidants into the thermoplastic polyolefins and having one or more feed ports for feeding one or more materials into said melting / compounding zone; a mixing zone configured for rapid blending of a curative additive into a polymer melt and having one or more injection ports located between the melting / compounding zone and the mixing zone for injecting one or more materials including the curative additive into the mixing zone; and an output zone for discharging a melt stream of compounded material from the melt compounding device into a post-compounding device; The method comprises: (A) providing the melt of the intermediate compound to the melting / compounding zone, or preparing the melt of the intermediate compound in the melting / compounding zone; (B) conveying the melt of the intermediate compound into the mixing zone; (C) injecting the combination of the curing agent additive comprising the one or more organic peroxides and the one or more polyene-based crosslinking aids into the melt of the intermediate compound through at least one of the one or more injection ports of the mixing zone; and (D) mixing the combination of the curing agent additive and the melt of the intermediate compound in the mixing zone to prepare a melt of the crosslinkable compound composition comprising the homogeneous mixture, wherein the homogeneous mixture is formed within 20.0 seconds to 60.0 seconds after the injecting step is completed; and (E) conveying the melt of the cross-linkable compound composition to the output zone.

7. The method according to claim 5 or claim 6, comprising a post-output zone step suitable for a pelletizer equipped with a strand die, a cooling tool and a cutting device, the post-output zone step comprising conveying the melt of the crosslinkable compound composition from the output zone of the melt compounding device to the pelletizer; extruding a strand of the cross-linkable compound composition; cooling the strand; and cutting the strands to produce solid pellets of the crosslinkable compound composition.

8. The method according to claim 5 or claim 6, comprising a post-output zone step suitable for an insulation extruder equipped with an annular die for extruding coated filaments, the post-output zone step comprising conveying the melt of the crosslinkable compound composition from the output zone of the melt compounding device into the insulation extruder; extruding a layer of the crosslinkable compound composition onto a conductor to prepare a coated conductor; and curing the crosslinkable compound composition of the insulation layer to prepare a cable.

9. The method of any one of claims 5 to 8, wherein the injecting step has limitation (i) or limitation (ii): (i) wherein the injecting step comprises injecting the combination of curing agent additives together as a mixture thereof, or (ii) wherein the injecting step comprises injecting at least one of the curing agent additives, alternatively all of the curing agent additives except one, alternatively each curing agent additive separately from the other curing agent additives.

10. The method according to any one of claims 1 to 9, wherein the one or more thermoplastic polyolefins are selected for high temperature / low scorch manufacture of insulation layers of cables at high production speeds and low scorch, wherein the one or more thermoplastic polyolefins have any one of limitations (i) to (iii): (i) wherein one or more thermoplastic polyolefins are present and at least one of the one or more thermoplastic polyolefins, alternatively each thermoplastic polyolefin is independently a low density polyethylene having a molecular weight of 0.870 g / cm2 as measured according to ASTM D792 Method B. 3 Up to 0.940g / cm 3 and a melt index (I2) of 1 g / 10 min to 20 g / 10 min as determined at 190°C and 2.16 kg in accordance with ASTM D1238; or (ii) wherein one or more thermoplastic polyolefins are present and each thermoplastic polyolefin is independently selected from the group consisting of polyethylene homopolymers, ethylene / 1-butene copolymers, ethylene / 1-hexene copolymers and ethylene / 1-octene copolymers; or (iii) Limit the combination of (i) and (ii).

11. The method according to any one of claims 1 to 10, wherein the additive is selected for high temperature / low scorch manufacturing of an insulation layer of a cable, wherein the additive has any one of limitations (i) to (v): (i) the one or more antioxidants include a sulfur-based antioxidant; or (ii) wherein the one or more polyalkenyl crosslinking aids comprise an alkenyl-containing monocyclic organosiloxane of formula (I): 1 ,R 2 SiO 2 / 2 ] n (I), wherein the subscript n is an integer greater than or equal to 3; Each R 1 are independently (C2-C4)alkenyl or H2C═C(R 1a )—C(═O)—O—(CH2) m —, where R 1a is H or methyl, and the subscript m is an integer from 1 to 4; And each R 2 are independently H, (C1-C4) alkyl, phenyl or R 1 ;or (iii) restrict the combination of (i) and (ii); (iv) wherein the one or more organic peroxides comprises dicumyl peroxide or a cumyl-containing peroxide; or (v) A combination of restriction (iv) and any one of restrictions (i) to (iii).

12. The method according to any one of claims 1 to 11, wherein the crosslinkable compound composition is formulated for high temperature / low scorch production of a crosslinkable insulation layer of a cable, wherein the crosslinkable compound composition has any one of limitations (i) to (iii): (i) the cross-linkable compound composition has: a scorch time at 140°C (ts1) of at least 63 minutes, alternatively at least 79 minutes, reported as the time required to increase by 1 pound-force-inch (lbf-in) or 1.13 deciNewton-meters (dN-m) from minimum torque ("ML") at 140°C as determined by moving die rheometer (MDR) testing in accordance with ASTM procedure D5289; and a maximum torque at 182°C (MH) that is at least 1.67 deciNewton-meters (dN-m; equal to at least 1.48 lbf-in) higher than the minimum torque at 182°C (ML), alternatively MH is at least 1.72 dN-m higher (at least 1.52 lbf-in higher) than ML at 182°C and MH at 182°C is at least 1.79 dN-m (1.58 lbf-in), alternatively at least 1.83 dN-m (1.62 lbf-in), as determined by moving die rheometer (MDR) testing in accordance with ASTM procedure D5289; or (ii) the crosslinkable compound composition has a hot creep elongation at 200°C of less than 130%, alternatively less than 100%, as tested in accordance with ICEA T-28-562a; or (iii) Limit the combination of (i) and (ii).

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