BR112020011846B1 - POLYMER COMPOSITION COMPRISING A POLYETHYLENE - Google Patents

Abstract

The present invention relates to a polymer composition comprising a polyethylene and a cross-linking agent, wherein the polymer composition contains a total amount of vinyl groups consisting of B vinyl groups per 1,000 carbon atoms and B1 = B, in that B1 is 0.88 when measured before cross-linking in accordance with the ASTM D6248-98 method; and wherein the crosslinking agent is present in an amount that is Z% by weight, based on the total amount (100% by weight) of the polymer composition, and Z = Z2, wherein Z2 is 0.60, a article that is, for example, a cable, for example, a power cable and processes for producing a polymer composition and an article; useful in different end applications such as wire and cable (W&C) applications.

Description

FIELD OF INVENTION

[0001] The present invention relates to a polymer composition comprising a polyethylene and a cross-linking agent, an article comprising layer (or layers), for example, insulating layer (or layers), which is obtained from the polymer composition, the article may be a cable, for example, a power cable, processes for producing the polymer composition and the article comprising the use of a polymer composition. Furthermore, the polymer composition may be useful in different end applications, such as wire and cable (W&C) applications, especially in cable applications, such as power cable applications, for example, in medium voltage (MV) and , for example in high voltage (HV) and, for example, in extra-high voltage (EHV) cable applications. Additionally, the polymer composition may be useful in alternating current (AC) and direct current (DC) applications.

BACKGROUND OF THE TECHNIQUE

[0002] Polyethylenes produced in a high pressure (HP) process are widely used in demanding polymer applications, where polymers must meet high mechanical and/or electrical requirements. For example, in W&C applications, e.g., power cable applications, e.g., in low voltage (LV), MV, HV, and EHV applications, the mechanical and electrical properties of polyethylenes, and polymer compositions comprising polyethylenes , are of significant importance.

[0003] For example, in power cable applications, particularly in MV and especially HV and EHV cable applications, the electrical properties of the polymer composition are of significant importance. Furthermore, electrical properties, which are important, may differ in different cable applications, as is the case between AC and DC cable applications.

[0004] Furthermore, it is further known that the cross-linking of polymers, for example, polyethylenes, contributes substantially to improved heat and deformation resistance, mechanical strength, chemical resistance and abrasion resistance of a polymer. Therefore, cross-linked polymers are widely used in different end applications, such as the mentioned W&C applications.

[0005] Furthermore, in cable applications, an electrical conductor is generally coated first with an inner semiconductor layer, followed by an insulating layer and an outer semiconductor layer. To these layers, another layer (or layers) may be added, such as screen (or screens) and/or auxiliary barrier layer (or layers), for example, one or more water barrier layers and one or more jacket layers. .

[0006] Due to the benefits mentioned herein, which are achievable with crosslinking, the insulating layer and semiconductor layers in cable applications are typically produced using crosslinkable polymer compositions. The polymer compositions in a layered cable application are then cross-linked.

[0007] Furthermore, such crosslinkable polymer compositions comprising low-density polyethylene (LDPE) are among the predominant cable insulating materials for power cables today.

[0008] Crosslinking can be carried out with crosslinking agents in which the crosslinking agents decompose generating free radicals. Such cross-linking agents, for example peroxides, are conventionally added to the polymeric material before or during cable extrusion. Said crosslinking agent should preferably remain stable during the extrusion step. The extrusion step should preferably be carried out at a temperature low enough to minimize early decomposition of the cross-linking agent, but high enough to achieve adequate melting and homogenization of the polymer composition. If a significant amount of cross-linking agent, e.g. peroxide, is already decomposed in the extruder and thus starts premature cross-linking, it will result in the formation of so-called “burning”, i.e. inhomogeneity, surface irregularity and possibly discoloration in the different layers of the resulting cable. Therefore, any significant decomposition of crosslinking agents, i.e. free radical forming agents, during extrusion must be avoided. Instead, crosslinking agents should ideally decompose merely in a subsequent crosslinking step at elevated temperature. Elevated temperature will increase the rate of decomposition of crosslinking agents and thus increase the speed of crosslinking and a desired degree of crosslinking, i.e. a target, can be achieved more quickly.

[0009] Furthermore, when a polymer composition in, for example, a cable, is cross-linked, the decomposition of cross-linking agents, for example, peroxides, during cross-linking, will also result in the formation of peroxide decomposition products. Some of the peroxide decomposition products are volatile and their main component is methane if the types of peroxides that are normally used for cross-linking in relation to, for example, a cable, are used. Peroxide decomposition products remain mainly captured within the polymer composition of, for example, a cable, after cross-linking. This causes, for example, problems in view of the cable manufacturing process, as well as in view of the quality of the final cable.

[0010] Especially MV, HV and EHV power cables must have high quality layers to help with safety during installation and in the final use of said cables. In installation, for example, it is important to prevent captured decomposition products, e.g. flammable methane, from igniting, for example when covers are removed. During service, volatile peroxide decomposition products formed in a cable during a cross-linking step can create gas pressure and therefore cause shielding and joint defects. For example, when a cable core is equipped with a metal barrier, then gaseous products can exert pressure, especially at joints and terminations, whereby system failure can occur. Therefore, the level of these volatile peroxide decomposition products needs to be reduced to a low enough level before subsequent cable production steps can take place.

[0011] A sufficiently low level of volatile peroxide decomposition products makes a use of the polymer composition comprising LDPE safe for use in installations, such as cable installations, and with accessories, such as cable accessories. Therefore, today a degassing step, which reduces the level of volatile peroxide decomposition products, is necessary in the cable production process. The degassing step is a time and energy consuming and therefore expensive operation in a cable manufacturing process. Degassing requires large heated chambers that must be well ventilated to prevent the accumulation of, for example, flammable methane. The cable core, i.e. layers and conductor, normally wound on cable drums, is normally kept in said degassing step at elevated temperature in the range of 50 to 80 °C, e.g. 60 to 70 °C, for long periods of time. When exposed to the required temperatures, thermal expansion and softening of the insulation may occur and lead to unwanted deformations of the formed cable layers, directly resulting in cable failures. Degassing of HV and EHV cables with high cable weights therefore needs to be frequently carried out at lower temperatures, which further prolongs the degassing time. Consequently, it is necessary to find new solutions to overcome the problems of the prior art.

[0012] Furthermore, cross-linking of a polymer composition, comprised, for example, in a cable, contributes substantially to improving the heat and creep resistance, mechanical strength, chemical resistance and abrasion resistance of the polymer composition and of the cable comprising polymer composition.

[0013] In this context, see document No. US5539075, which refers to a method for producing an unsaturated copolymer of ethylene and at least one monomer, wherein the monomer is a polyunsaturated compound and copolymerizable with ethylene.

[0014] See also document No. EP2318210B1, which refers to a polymer composition comprising an ethylene-unsaturated LDPE copolymer with one or more polyunsaturated comonomers and which is suitable for cross-linked polymer applications. The polymer composition has a melt flow rate under 2.16 kg load, MFR2, of at least 2.8 g/10 min, and contains carbon-carbon double bonds in an amount of at least 0.40 double bonds. carbon-carbon/1,000 carbon atoms.

[0015] Furthermore, different materials, i.e. polymer compositions, may be required for different cables, constructions and cable lines. Furthermore, it is not possible to route all cables or cable constructions in all cable lines with the use of, so called in this document, “cross-linked” polyethylene (XLPE) materials (which here means, more correctly, “cross-linkable”). ”) of standard viscosity that have a melt flow rate under load of 2.16 kg, MFR2, values around 2 g/10 min. This is because these standard viscosity XLPE materials do not have sufficient resistance to sagging. Insufficient sagging resistance is normally resolved, in the case of a cable, by using materials with MFR2 values lower than 2 g/10 min. Materials with MFR2 values less than 2 g/10 min have high viscosity and better resistance to sagging. Improved sagging resistance is required for large cable constructions and for cable production in catenary cable lines as well as for cable production in horizontal cable lines. For example, in horizontal continuous vulcanization lines, e.g. a Mitsubishi Dainichi Continuous Vulcanization (MDCV) line and in catenary continuous vulcanization (CCV) lines (especially for thicker constructions) for the production of cables, the use of polymeric materials, for example for insulation layers, which have lower MFR2 compared to the MFR2 of polymeric materials (e.g. standard viscosity XLPE materials) used in vertical continuous vulcanization (VCV) lines and CCV (for thinner constructions).

[0016] In horizontal continuous vulcanization lines for cable production, the conductor may sink into the insulation layer; If polymeric materials are used that have a very high MFR2, conductor sag can also result in cable core runout.

[0017] Likewise, in CCV lines, if polymeric materials with a very high MFR2 are used, that is, which also have a very low sagging resistance, the wall thickness may become very large, as the polymeric material soft melt of an insulation layer may fall off the conductor. This will result in a downward mode shift of the insulation layer, resulting in an eccentricity, for example, a so-called pear-shaped cable core.

[0018] Furthermore, insufficient resistance to sagging can be neutralized by different methods, such as:

[0019] use of eccentric tools in the extruder head to compensate for the conductor sinking effect;

[0020] twisting the cable core to counteract the displacement of the conductor,

[0021] use of a double rotation technique to neutralize the pear-shaped conformation and also use of the so-called entry heat treatment (EHT).

[0022] Consequently, polymeric materials that have a comparatively lower MFR2 and a higher viscosity, as already described, are typically used to combat these sagging behaviors.

[0023] However, materials that have high viscosity generate a higher melting temperature under commonly used extrusion conditions, which can lead to a greater risk of premature cross-linking and thus formation of prematurely cross-linked matter, i.e. “ burn". “Burning” may, as already described herein, be inhomogeneity, surface irregularity and/or possibly discoloration in the different layers, for example, of the resulting cable. The formation of “burn” can have a serious impact on productivities in cable lines as it significantly limits the production time before cleaning is required and therefore the production rate is reduced. Therefore, when producing a cable using polymeric materials with a lower MFR2, generating a higher melting temperature, a lower production speed is required to reduce the melting temperature and thus minimize “burning”.

[0024] Consequently, a disadvantage with decreasing the MFR2 value of a material may be that it also requires changes in processing conditions, such as a decrease in production speed.

[0025] Processing conditions are, in addition to sagging resistance, also important properties in relation to crosslinkable XLPE materials, such as peroxide crosslinkable XLPE materials. Ideally, the material should have low viscosity under the extrusion step of the process in order to have, under the extrusion step, a desirably low melting temperature. On the other hand, in the crosslinking step of the process, a comparatively higher viscosity of the material may be desirable. If a crosslinkable XLPE material generates a low melting temperature, there is less risk of “burn” forming during an extrusion of, for example, a cable construction, compared to an extrusion involving another crosslinkable XLPE material, generating a highest melting temperature.

[0026] Sagging resistance and viscosity under processing conditions can be visualized by viscosity curves obtained from plate-plate rheology measurements. Said sagging resistance is then visualized through the complex viscosity (n*) at very low shear rates, i.e., n*o and n*0.05 at 0 rad/s and 0.05 rad/s, respectively, and said viscosity under processing conditions is then visualized through the complex viscosity h*300 at 300 rad/s.

[0027] Yet another important property for XLPE is the degree of crosslinking in which the target degree of crosslinking should be achieved with, ideally, as low an amount of crosslinking agent as possible, such as peroxide. The degree of crosslinking can, for example, be measured with a so-called hot set test. According to the said hot test, the lower the hot elongation value, the more crosslinked the material is. As low a quantity of the cross-linking agent as possible reduces volatile peroxide decomposition products and also reduces the time required for outgassing.

[0028] The extrusion and crosslinking steps of a polymeric material included, for example, in the production of cables, have different requirements. The critical parameter for the extrusion step is, as already described, that the polymeric material generates a low melting temperature, in order to reduce the risk of “burning”. This is influenced by the rheological properties in the shear rate region that the polymeric material exhibits in the extruder, for example when using a low complex viscosity (n*) at 300 rad/s. A low viscosity complex (n*) at 300 rad/s is generally connected to a polymeric material with a higher melt flow rate (MFR2).

[0029] However, an increase in the melt flow rate must generally be balanced, as a polymeric material with a high MFR2 has a very low sagging resistance, which will result in, for example, a non-centered cable, which is not acceptable. The rheological property that influences sagging resistance is complex viscosity (n*) at very low shear rates, such as 0 rad/s. However, the complex viscosity (n*) at 0 rad/s is an extrapolated value and therefore a measured complex viscosity (n*) at 0.05 rad/s is used here.

[0030] Consequently, it is necessary to find new solutions to overcome the problems of the prior art.

DESCRIPTION OF THE INVENTION

[0031] The present invention relates to a polymer composition comprising a polyethylene and a cross-linking agent, wherein the polymer composition contains a total amount of vinyl groups consisting of B vinyl groups per 1,000 carbon atoms, and B1 < B, where Bi is 0.88, when measured before cross-linking according to ASTM D6248-98 method; and the crosslinking agent is present in an amount that is Z% by weight, based on the total amount (100% by weight) of the polymer composition, and Z < Z2, where Z2 is 0.60.

[0032] In one embodiment, the inventors have found that the combination of the aforementioned features with a relatively low MFR2 surprisingly leads to a polymer composition with attractive properties, as discussed below.

[0033] The polymer composition according to the present invention that contains the comparatively highest total amount of vinyl groups, B, as defined herein, surprisingly combines, in a polymer composition:

[0034] good processability, for example, good fluidity, generally associated only with materials that have a comparatively higher MFR2, with

[0035] excellent sagging resistance generally associated only with materials that have a comparatively lower MFR2, and

[0036] display of surprisingly low methane levels, with a technically desirable level of degree of cross-linking maintained.

[0037] Furthermore, the polymer composition that combines excellent sagging resistance and good processability, e.g. fluidity, is also illustrated by the fact that the polymer composition exhibits balanced complex viscosities (n*) at 300 rad/s and at 0 .05 rad/s, both complex viscosities (n*) are determined before cross-linking according to the ISO 6721-1 method on stabilized polyethylene samples. The complex viscosity (n*) at 300 rad/s is consequently low, and the complex viscosity (n*) at 0.05 rad/s is consequently high, which results in a polymer composition according to the present invention , which improved the processing properties in an extruder, and which also allows the generation of a cable, including large cable constructions, with good centrality in cable production for all types of cable lines. Such cables, which comprise layers, for example insulation layers, which are obtained from the polymer composition, can thus be produced accordingly.

[0038] Furthermore, the polymer composition according to the present invention has unexpectedly also been shown to exhibit surprisingly low levels of methane, while at the same time a technically desirable level of degree of cross-linking of the polymer composition is maintained. with the use of a relatively low amount of the crosslinking agent, i.e. Z% by weight, as defined herein. The technically desirable level of degree of crosslinking ensures sufficient thermomechanical properties, e.g. maintenance of dimensional stability at elevated temperature. The crosslinking agent may, for example, be peroxides which are well known in the art. The amount of volatile decomposition products formed, where the main component is typically methane, directly depends on the amount of cross-linking agent, for example peroxide, that is added to the polymer composition. For any crosslinking agent, for example peroxide, the amount of volatile decomposition products formed also depends on the chemical structure of the crosslinking agent. Furthermore, by selecting said relatively low amount of cross-linking agent, while the desirable level of degree of cross-linking of a polymer composition is maintained, a polymer composition that exhibits low levels of methane as well as retains a memory effect when crosslinked, it is activated.

[0039] These low levels of methane allow for shorter degassing times or, alternatively, make the degassing step completely redundant, whereby both alternatives are very beneficial for the overall production of crosslinkable and crosslinked articles, e.g., cables, which comprise a layer (or layers), for example an insulation layer, obtained from the polymer composition.

[0040] Thus, the polymer composition comprising polyethylene of the present invention is clearly highly advantageous for use in the production of crosslinkable and crosslinked articles, e.g., cables, e.g., cable layers thereof, e.g. cable insulation layers.

[0041] The polymer composition is crosslinkable and is highly suitable for the production of crosslinkable articles, for example, one or more crosslinkable layers of a cable, for example, one or more crosslinkable insulation layers of a cable, which layers are subsequently cross-linked.

[0042] “Cross-linkable” is a well-known expression and means that the polymer composition can be cross-linked, for example, through the formation of radicals, to form, among others, bridges between polymer chains.

[0043] The polymer composition comprises a polyethylene and a crosslinking agent.

[0044] Polyethylene will be described in detail in the section “Polyethylene of the polymer composition”.

[0045] The polyethylene comprised in the polymer composition of the present invention can be unsaturated or saturated.

[0046] An additional embodiment of the present invention is provided in which polyethylene is saturated.

[0047] Note that the words “embodiment” or “modalities”, even if they are isolated in the present document, always refer to the embodiment of the present invention or the modalities of the present invention.

[0048] In a further embodiment, a polymer composition of the present invention is provided that comprises a polyethylene, wherein the polyethylene is unsaturated.

[0049] That polyethylene is “unsaturated” in this document means that polyethylene comprises carbon-carbon double bonds. Carbon-carbon double bonds herein mean unsaturations. Polyethylene, as described herein, comprises vinyl groups, for example, allyl groups. Vinyl groups are functional groups that comprise carbon-carbon double bonds. The term "vinyl group" as used herein has a conventional meaning, that is, the chemical moiety "-CH=CH2". Furthermore, polyethylene may further comprise other functional groups which also comprise carbon-carbon double bonds. The other functional groups, which also comprise carbon-carbon double bonds, may be, for example, vinylidene groups and/or vinylene groups. The vinylene group has a cis or trans configuration. For the avoidance of doubt, vinylidene and vinylene groups are not vinyl groups as the terms are used herein.

[0050] Said “total amount of vinyl groups consisting of B vinyl groups per 1,000 carbon atoms” means the “total amount of vinyl groups consisting of B vinyl groups per 1,000 carbon atoms” present in the polymer composition when measured prior to cross-linking in accordance with the present invention. Furthermore, at least polyethylene contains said vinyl groups which contribute to the total amount of vinyl groups.

[0051] The polymer composition may optionally comprise additional component (or components) that contain vinyl groups, which also contribute to the total amount of said vinyl groups. In one embodiment, therefore, the vinyl group content is thus measured in the polymer composition as a whole and not just in the polyethylene thereof.

[0052] The ASTM D6248-98 method for determining the amount of vinyl groups is described in “Determination Methods”.

[0053] Yet a further embodiment of the polymer composition according to the present invention, as described herein, discloses a polymer composition, wherein the polymer composition contains a total amount of vinyl groups consisting of B vinyl groups per 1,000 carbon atoms and Bi < B, where Bi is 0.89, when measured before cross-linking according to the ASTM D6248-98 method.

[0054] An additional embodiment of the polymer composition is disclosed, in which Bi is 0.90.

[0055] In a further embodiment according to the present invention, a polymer composition as described herein is disclosed, wherein Bi is 0.92.

[0056] An even further embodiment of the polymer composition is disclosed, in which B1 is 0.94.

[0057] An additional embodiment of the polymer composition is disclosed, in which B1 is 0.95.

[0058] An even further embodiment of the polymer composition is disclosed, in which B1 is 1.00.

[0059] Additional embodiments of the polymer composition are disclosed, wherein B1 is 0.95, 1.00, 1.05 or 1.10.

[0060] Still additional embodiments of the polymer composition are disclosed, wherein B1 is 0.90, 0.95, 1.00, 1.05, 1.10, 1.15, 1.20, 1.25 or 1 .30.

[0061] Additional embodiments of the polymer composition are disclosed, wherein B1 is 0.90, 0.95, 1.00, 1.05, 1.10, 1.15, 1.20, 1.25 or 1, 30, and/or Z2 is 0.48 or 0.46.

[0062] Even additional embodiments of the polymer composition are disclosed, wherein B1 is 1.15, 1.20, 1.25 or 1.30.

[0063] An additional embodiment of the polymer composition is disclosed, in which B1 is 1.30.

[0064] A further embodiment of the polymer composition according to the present invention is disclosed, as described herein, in which B < B2 and B2 is 3.0.

[0065] Additional embodiments of the polymer composition are disclosed in which the polymer composition contains a total amount of vinyl groups consisting of B vinyl groups per 1,000 carbon atoms and B1 < B < B2, wherein B1 and B2 each , can be selected from any of the values given in this document for B1 and B2, respectively.

[0066] A further embodiment of the polymer composition according to the present invention, as described herein, is disclosed, wherein B2 is 2.5.

[0067] In a particularly preferred embodiment, B1 is 0.89 and B2 is 3.0, even more preferably B1 is 0.90 and B2 is 1.5.

[0068] The polymer composition additionally comprises a crosslinking agent.

[0069] The cross-linking agent, for example, a peroxide, is present in an amount that is Z% by weight, based on the total amount (100% by weight) of the polymer composition, and Z < Z2, where Z2 is 0.60.

[0070] In a further embodiment according to the present invention, the polymer composition as described herein, wherein the cross-linking agent is present in an amount that is Z% by weight, based on the total amount ( 100% by weight) of the polymer composition, and Zi < Z, where Zi is 0.01.

[0071] The crosslinking agent is defined in this document as any compound with the ability to generate radicals that can initiate a crosslinking reaction. For example, the crosslinking agent contains an -O-O- bond.

[0072] A further embodiment of the polymer composition according to the present invention, as described herein, is disclosed, wherein the crosslinking agent comprises peroxide, for example, a peroxide.

[0073] In a further embodiment, the crosslinking agent comprises peroxide, that is, it comprises at least one peroxide unit per molecule of crosslinking agent.

[0074] In an even further embodiment, the crosslinking agent comprises a peroxide.

[0075] In an additional embodiment, the crosslinking agent is a peroxide.

[0076] According to additional embodiments of the present invention, a polymer composition as described herein is disclosed, wherein Z1 is 0.02, 0.04, 0.06 or 0.08.

[0077] Furthermore, embodiments of the polymer composition according to the present invention are disclosed, as described, in which Z1 is, for example, 0.1 or 0.2 and/or Z2 is, for example, 0.58 or 0.56.

[0078] In an additional embodiment Z2 is 0.58 or 0.56. In yet a further embodiment, Z2 is 0.58. In an even further embodiment, Z2 is 0.56. In a further embodiment, Z2 is 0.54, 0.52 or 0.50. In yet a further embodiment, Z2 is 0.54. In an even further embodiment, Z2 is 0.52. In a further embodiment, Z2 is 0.50.

[0079] In an additional embodiment, Z2 is 0.48 or 0.46. In yet a further embodiment, Z2 is 0.48. In an even further embodiment, Z2 is 0.46.

[0080] A further embodiment of the polymer composition according to the present invention, as described in the present document, is disclosed, in which the amount Z of the crosslinking agent, for example, a peroxide, is Z2 which is 0.45.

[0081] A further embodiment of the polymer composition according to the present invention, as described herein, is disclosed, wherein Z2 is 0.44 or 0.42.

[0082] In yet a further embodiment, the amount Z of the crosslinking agent, for example, a peroxide, is Z2 which is 0.40.

[0083] A further embodiment of the polymer composition according to the present invention, as described herein, is disclosed, wherein Z2 is 0.38 or 0.36.

[0084] Yet another embodiment of the polymer composition according to the present invention, as described herein, is disclosed, wherein Z2 is 0.38.

[0085] An additional embodiment of the polymer composition according to the present invention, as described herein, is disclosed, wherein Z2 is 0.36.

[0086] In an even further embodiment, the amount Z of the crosslinking agent, for example, a peroxide, is Z2 which is 0.35.

[0087] A further embodiment of the polymer composition according to the present invention, as described herein, is disclosed, wherein Z2 is 0.34, 0.32 or 0.30.

[0088] Yet another embodiment of the polymer composition according to the present invention, as described herein, is disclosed, wherein Z2 is 0.34.

[0089] An additional embodiment of the polymer composition according to the present invention, as described herein, is disclosed, wherein Z2 is 0.32.

[0090] Yet another embodiment of the polymer composition according to the present invention, as described herein, is disclosed, wherein Z2 is 0.30.

[0091] Non-limiting examples of crosslinking agents include organic peroxides, such as di-tert-amylperoxide, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexine-3, 2,5-di(tert- butylperoxy)-2,5-dimethylhexane, tert-butylcumylperoxide, di(tert-butyl)peroxide, dicumylperoxide, butyl-4,4-bis(tert-butylperoxy)-valerate, 1,1-bis(tert-butylperoxy) -3,3,5-trimethylcyclohexane, tert-butylperoxybenzoate, dibenzoylperoxide, bis(tert-butylperoxy-isopropyl)benzene, 2,5-dimethyl-2,5-di(benzoylperoxy)hexane, 1,1-di(tert- butylperoxy)cyclohexane, 1,1-di(tert-amylperoxy)cyclohexane or any mixtures thereof.

[0092] In additional embodiments, the crosslinking agent which is a peroxide can, for example, be selected from 2,5-dimethyl-2,5-di(tert-butylperoxy)hexine-3, 2,5-di (tert-butylperoxy)-2,5-dimethylhexane, di(tert-butylperoxyisopropyl)benzene, dicumylperoxide, tert-butylcumylperoxide, di(tert-butyl)peroxide or any mixtures thereof.

[0093] In yet a further embodiment, the crosslinking agent is a peroxide selected from any one of dicumylperoxide, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexine-3 and tert-butylcumylperoxide or any mixture of them.

[0094] In an additional embodiment, the crosslinking agent comprises a peroxide that is dicumylperoxide.

[0095] In yet another embodiment, the crosslinking agent comprises a peroxide that is 2,5-dimethyl-2,5-di(tert-butylperoxy)hexine-3.

[0096] In yet another embodiment, the crosslinking agent comprises a peroxide that is tert-butylcumylperoxide.

[0097] In one embodiment, the polymer composition comprises the crosslinking agent.

[0098] Yet a further embodiment of the polymer composition according to the present invention, as described herein, is disclosed, wherein B < B2 and B2 is 3.0 and

[0099] Z1 ≤ Z ≤ Z2, where Zi is 0.01.

[0100] Additional embodiments of the polymer composition are disclosed, as described herein, wherein the crosslinking agent is present in an amount that is Z% by weight, based on the total amount (100% by weight) of the polymer composition. polymer, and Z1 < Z < Z2, where Z1 and Z2 can each be selected from any of the values given herein for Z1 and Z2, respectively.

[0101] In a further embodiment according to the present invention, as described herein, Z1 is 0.05.

[0102] An additional embodiment of the polymer composition according to the present invention, as described herein, is disclosed, wherein Z1 is 0.10.

[0103] Yet another embodiment of the polymer composition according to the present invention, as described herein, is disclosed, wherein Z2 is 0.15.

[0104] A further embodiment of the polymer composition according to the present invention, as described herein, is disclosed, wherein Z2 is 0.20.

[0105] In a particularly preferred embodiment, Z1 is 0.15 and Z2 is 0.60, even more preferably, Z1 is 0.25 and Z2 is 0.50.

[0106] MFR2 is determined before crosslinking, in accordance with ISO 1133-1:2011, under a load of 2.16 kg and at 190 °C.

[0107] In a further embodiment according to the present invention, the polymer composition as described herein has prior to cross-linking a melt-load flow rate of 2.16 kg (MFR2) and at 190 °C , determined, according to the ISO 1133-1:2011 method, the MFR2 which is A g/10 min and A < A2, where A2 is 10.

[0108] A further embodiment of the polymer composition according to the present invention, as described herein, is disclosed, wherein A2 is 5.0.

[0109] In a further embodiment of the polymer composition, A2 is 4.0.

[0110] Yet another embodiment of the polymer composition according to the present invention, as described herein, is disclosed, wherein A2 is 3.0.

[0111] In yet a further embodiment, the polymer composition according to the present invention, as described herein, is disclosed, in which A2 is 2.7.

[0112] A further embodiment of the polymer composition according to the present invention, as described herein, is disclosed, wherein A2 is 2.5.

[0113] Yet another embodiment of the polymer composition according to the present invention, as described herein, is disclosed, wherein A2 is 2.0.

[0114] A further embodiment of the polymer composition according to the present invention, as described herein, is disclosed, wherein A2 is 1.7.

[0115] In yet a further embodiment, the polymer composition has a melt flow rate, MFR2, which is A g/10 min and Ai < A; where Ai is 0.05.

[0116] Additional embodiments of the polymer composition are disclosed that have a melt flow rate, MFR2, that is A g/10 min and A1 < A < A2; wherein A1 and A2 may each be selected from any of the values given herein for A1 and A2, respectively.

[0117] Yet another embodiment of the polymer composition according to the present invention, as described herein, is disclosed, wherein A1 is 0.10.

[0118] An additional embodiment of the polymer composition according to the present invention, as described herein, is disclosed, wherein A1 is 0.15.

[0119] An embodiment of the polymer composition according to the present invention, as described herein, is disclosed, wherein A1 is 0.20.

[0120] Still an embodiment according to the present invention, as described in the present document, is disclosed, in which A1 is 0.25.

[0121] An additional embodiment in accordance with the present invention, as described herein, is disclosed, wherein A1 is 0.30.

[0122] An embodiment according to the present invention, as described herein, is disclosed, wherein A1 is 0.35.

[0123] Still an embodiment according to the present invention, as described in the present document, is disclosed, in which A1 is 0.40.

[0124] An additional embodiment in accordance with the present invention, as described herein, is disclosed, wherein A1 is 0.45.

[0125] An embodiment according to the present invention, as described herein, is disclosed, wherein A1 is 0.50.

[0126] An additional embodiment according to the present invention, as described herein, is disclosed, wherein A1 is 0.55.

[0127] An embodiment according to the present invention, as described herein, is disclosed, wherein A1 is 0.60.

[0128] Still an embodiment according to the present invention, as described in the present document, is disclosed, in which A1 is 0.65.

[0129] An additional embodiment in accordance with the present invention, as described herein, is disclosed, wherein A1 is 0.70.

[0130] An embodiment according to the present invention, as described herein, is disclosed, in which A1 is 0.75.

[0131] Yet another embodiment according to the present invention, as described in the present document, is disclosed, in which A1 is 0.80.

[0132] An additional embodiment according to the present invention, as described herein, is disclosed, wherein A1 is 0.85.

[0133] An embodiment according to the present invention, as described herein, is disclosed, wherein A1 is 0.90.

[0134] A further embodiment of the polymer composition according to the present invention, as described herein, is disclosed, wherein A2 is 1.65.

[0135] Yet another embodiment of the polymer composition according to the present invention, as described herein, is disclosed, wherein A2 is 1.60.

[0136] An embodiment of the polymer composition according to the present invention, as described herein, is disclosed, wherein A2 is 1.55.

[0137] An even further embodiment of the polymer composition according to the present invention, as described herein, is disclosed, wherein A2 is 1.50.

[0138] In a particularly preferred embodiment, A1 is 0.15 and A2 is 3.0, even more preferably, A1 is 0.60 and A2 is 2.5.

[0139] In a preferred embodiment, the polymer composition simultaneously satisfies the following:

[0140] B1 ≤ B≤ B2 where B1 is 0.89 and B2 is 3.0;

[0141] Z1 ≤ Z ≤ Z2 where Z1 is 0.15 and Z2 is 0.60; It is

[0142] A1 ≤ A ≤ A2 where A1 is 0.15 and A2 is 3.0;

[0143] preferably,

[0144] B1 ≤ B ≤ B2 where B1 is 0.9 and B2 is 1.5;

[0145] Z1 ≤ Z ≤ Z2 where Z1 is 0.25 and Z2 is 0.50; It is

[0146] A1 ≤ A ≤ A2 where A1 is 0.60 and A2 is 2.5

[0147] A further embodiment of the polymer composition according to the present invention, as described herein, is disclosed, wherein the polyethylene, prior to cross-linking, has a complex viscosity (n*) at 0.05 rad/s , which is X Pas, and

[0148] X1 ≤ X ≤ X2,

[0149] where Xi is 7,600 and X2 is 30,000, and

[0150] a complex viscosity (n*) at 300 rad/s, which is Y Pas, and Yi < Y < Y2, where Yi is 5 and Y2 is 380, both complex viscosities (n*) are determined accordingly with the ISO 6721-1 method on stabilized polyethylene samples.

[0151] Additional embodiments of the polymer composition are disclosed in which the polyethylene, prior to cross-linking, has a complex viscosity (n*) at 0.05 rad/s, determined in accordance with the ISO 6721-1 method on stabilized samples of the polyethylene, which is X Pas, and Xi < X < X2, where Xi and X2 can each be selected from any of the values given herein for Xi and

[0152] Still additional embodiments of the polymer composition are disclosed in which the polyethylene, prior to cross-linking, has a complex viscosity (n*) at 300 rad/s, determined in accordance with the ISO 6721-1 method on stabilized samples of polyethylene , which is Y Pas, and Yi < Y < Y2, where Yi and Y2 can be selected from any of the values given herein for Yi and Y2, respectively.

[0153] An embodiment of the polymer composition according to the present invention, as described herein, is disclosed, wherein Xi is 7.614.

[0154] An additional embodiment of the polymer composition according to the present invention, as described herein, is disclosed, wherein X1 is 8,000.

[0155] Yet another embodiment of the polymer composition according to the present invention, as described herein, is disclosed, wherein X1 is 9,000.

[0156] An embodiment of the polymer composition according to the present invention, as described herein, is disclosed, wherein X1 is 10,000.

[0157] An embodiment of the polymer composition according to the present invention, as described herein, is disclosed, wherein X1 is 11,000.

[0158] An additional embodiment of the polymer composition according to the present invention, as described herein, is disclosed, wherein X1 is 12,000.

[0159] Yet another embodiment of the polymer composition according to the present invention, as described herein, is disclosed, wherein X1 is 13,000.

[0160] An embodiment of the polymer composition according to the present invention, as described herein, is disclosed, wherein X1 is 14,000.

[0161] An additional embodiment of the polymer composition according to the present invention, as described herein, is disclosed, wherein X2 is 29,000.

[0162] An even further embodiment of the polymer composition according to the present invention, as described herein, is disclosed, wherein X2 is 28,000.

[0163] An embodiment of the polymer composition according to the present invention, as described herein, is disclosed, wherein X2 is 27,000.

[0164] A further embodiment of the polymer composition according to the present invention, as described herein, is disclosed, wherein X2 is 26,000.

[0165] Yet a further embodiment of the polymer composition according to the present invention, as described herein, is disclosed, wherein X2 is 25,000.

[0166] An embodiment of the polymer composition according to the present invention, as described herein, is disclosed, wherein X2 is 24,000.

[0167] An additional embodiment of the polymer composition according to the present invention, as described herein, is disclosed, wherein X1 is 15,000.

[0168] An even further embodiment of the polymer composition according to the present invention, as described herein, is disclosed, wherein X1 is 16,000.

[0169] An additional embodiment of the polymer composition according to the present invention, as described herein, is disclosed, wherein X1 is 17,000.

[0170] An even further embodiment of the polymer composition according to the present invention, as described herein, is disclosed, wherein X1 is 18,000.

[0171] An additional embodiment of the polymer composition according to the present invention, as described herein, is disclosed, wherein X1 is 18,100.

[0172] Yet another embodiment of the polymer composition according to the present invention, as described herein, is disclosed, wherein X1 is 18,200.

[0173] An embodiment of the polymer composition according to the present invention, as described herein, is disclosed, wherein X1 is 18,300.

[0174] An additional embodiment of the polymer composition according to the present invention, as described herein, is disclosed, wherein X1 is 18,400.

[0175] An even further embodiment of the polymer composition according to the present invention, as described herein, is disclosed, wherein X1 is 18,500.

[0176] An additional embodiment of the polymer composition according to the present invention, as described herein, is disclosed, wherein X1 is 18,600.

[0177] An even further embodiment of the polymer composition according to the present invention, as described herein, is disclosed, wherein X1 is 18,700.

[0178] A further embodiment of the polymer composition according to the present invention, as described herein, is disclosed, wherein X2 is 23,500.

[0179] An even further embodiment of the polymer composition according to the present invention, as described herein, is disclosed, wherein X2 is 23,000.

[0180] An additional embodiment of the polymer composition according to the present invention, as described herein, is disclosed, wherein X2 is 22,900.

[0181] Yet another embodiment of the polymer composition according to the present invention, as described herein, is disclosed, wherein X2 is 22,800.

[0182] An additional embodiment of the polymer composition according to the present invention, as described herein, is disclosed, wherein X2 is 22,700.

[0183] An embodiment of the polymer composition according to the present invention, as described herein, is disclosed, wherein X2 is 22,600.

[0184] An additional embodiment of the polymer composition according to the present invention, as described herein, is disclosed, wherein X2 is 22,500.

[0185] A further embodiment of the polymer composition according to the present invention, as described herein, is disclosed, wherein X2 is 22,400.

[0186] An even further embodiment of the polymer composition according to the present invention, as described herein, is disclosed, wherein X2 is 22,300.

[0187] A further embodiment of the polymer composition according to the present invention, as described herein, is disclosed, wherein Y1 is 10.

[0188] A further embodiment of the polymer composition according to the present invention, as described herein, is disclosed, wherein Y1 is 20.

[0189] A further embodiment of the polymer composition according to the present invention, as described herein, is disclosed, wherein Y1 is 30.

[0190] Yet a further embodiment of the polymer composition according to the present invention, as described herein, is disclosed, wherein Y1 is 40.

[0191] An embodiment of the polymer composition according to the present invention, as described herein, is disclosed, wherein Y1 is 50.

[0192] A further embodiment of the polymer composition according to the present invention, as described herein, is disclosed, wherein Y1 is 60.

[0193] An even further embodiment of the polymer composition according to the present invention, as described herein, is disclosed, wherein Y1 is 70.

[0194] A further embodiment of the polymer composition according to the present invention, as described herein, is disclosed, wherein Y1 is 80.

[0195] An even further embodiment of the polymer composition according to the present invention, as described herein, is disclosed, wherein Y1 is 90.

[0196] A further embodiment of the polymer composition according to the present invention, as described herein, is disclosed, wherein Y1 is 100.

[0197] An even further embodiment of the polymer composition according to the present invention, as described herein, is disclosed, wherein Y1 is 110.

[0198] An embodiment of the polymer composition according to the present invention, as described herein, is disclosed, wherein Y1 is 120.

[0199] A further embodiment of the polymer composition according to the present invention, as described herein, is disclosed, wherein Y1 is 130.

[0200] Yet a further embodiment of the polymer composition according to the present invention, as described herein, is disclosed, wherein Y1 is 140.

[0201] An embodiment of the polymer composition according to the present invention, as described herein, is disclosed, wherein Y1 is 150.

[0202] A further embodiment of the polymer composition according to the present invention, as described herein, is disclosed, wherein Y1 is 160.

[0203] An even further embodiment of the polymer composition according to the present invention, as described herein, is disclosed, wherein Y1 is 170.

[0204] A further embodiment of the polymer composition according to the present invention, as described herein, is disclosed, wherein Y1 is 180.

[0205] An even further embodiment of the polymer composition according to the present invention, as described herein, is disclosed, wherein Y1 is 190.

[0206] An embodiment of the polymer composition according to the present invention, as described herein, is disclosed, wherein Y1 is 200.

[0207] A further embodiment of the polymer composition according to the present invention, as described herein, is disclosed, wherein Y1 is 210.

[0208] Yet a further embodiment of the polymer composition according to the present invention, as described herein, is disclosed, wherein Y1 is 220.

[0209] An embodiment of the polymer composition according to the present invention, as described herein, is disclosed, wherein Y1 is 230.

[0210] A further embodiment of the polymer composition according to the present invention, as described herein, is disclosed, wherein Y1 is 240.

[0211] An even further embodiment of the polymer composition according to the present invention, as described herein, is disclosed, wherein Y1 is 250.

[0212] An embodiment of the polymer composition according to the present invention, as described herein, is disclosed, wherein Y2 is 378.

[0213] An even further embodiment of the polymer composition according to the present invention, as described herein, is disclosed, wherein Y2 is 375.

[0214] A further embodiment of the polymer composition according to the present invention, as described herein, is disclosed, wherein Y2 is 360.

[0215] Yet a further embodiment of the polymer composition according to the present invention, as described herein, is disclosed, wherein Y2 is 355.

[0216] An embodiment of the polymer composition according to the present invention, as described herein, is disclosed, wherein Y2 is 350.

[0217] Even an additional embodiment of the polymer composition according to the present invention, as described herein, is disclosed, wherein Y2 is 345.

[0218] A further embodiment of the polymer composition according to the present invention, as described herein, is disclosed, wherein Y2 is 340.

[0219] Yet a further embodiment of the polymer composition according to the present invention, as described herein, is disclosed, wherein Y2 is 335.

[0220] An embodiment of the polymer composition according to the present invention, as described herein, is disclosed, wherein Y2 is 330.

[0221] Yet a further embodiment of the polymer composition according to the present invention, as described herein, is disclosed, wherein X1 is 8,000 and X2 is 28,000 and wherein Y1 is 250 and Y2 is 360.

[0222] A further embodiment of the polymer composition according to the present invention, as described herein, is disclosed, wherein X1 is 12,000 and X2 is 28,000 and wherein Y1 is 250 and Y2 is 330.

[0223] Yet a further embodiment of the polymer composition according to the present invention, as described herein, is disclosed, wherein X1 is 13,000 and X2 is 27,000, and wherein Y1 is 240 and Y2 is 340.

[0224] An even further embodiment of the polymer composition according to the present invention, as described herein, is disclosed, wherein X1 is 13,000 and X2 is 27,000, and wherein Y1 is 250 and Y2 is 330.

[0225] In additional embodiments, the polymer composition may also comprise additional additive (or additives). This additional additive (or additives) comprises:

[0226] low molecular weight unsaturated compound (or compounds), for example:

[0227] - Crosslinking reinforcer (or reinforcers) mentioned herein, including any specific compound (or compounds), which can contribute to the degree of crosslinking and/or the amount of vinyl groups in the polymer composition.

[0228] - One or more burn retardants (SR) which are defined herein as compounds that reduce burn formation during extrusion of a polymer composition, at typical extrusion temperatures used, compared to the same polymer composition. extruded polymer without said compound. Burn retardants can also contribute to the total amount of vinyl groups in the polymer composition.

[0229] Any contribution of the low molecular weight unsaturated compound (or compounds), for example, the crosslinking reinforcer (or reinforcers) and/or the “one or more” burn retardants (SR) to the amount of vinyl groups in the Polymer composition is also measured according to the ASTM D6248-98 method.

[0230] The crosslinking enhancer can be a compound that contains at least 2 unsaturated groups, such as an aliphatic or aromatic compound, an ester, an ether, an amine or a ketone, which contains at least 2 unsaturated groups, such as a cyanurate, an isocyanurate, a phosphate, an orthoformate, an aliphatic or aromatic ether or an allylic ester of benzene tricarboxylic acid. Examples of esters, ethers, amines and ketones are compounds selected from the general groups of diacrylates, triacrylates, tetraacrylates, triallylcyanurate, triallylisocyanurate, 3,9-divinyl-2,4,8,10-tetra-oxaspiro[5, 5]-undecane (DVS), triallyl trimellitate (TATM) or N,N,N',N',N",N”- hexa-allyl-1,3,5-triazine-2,4,6-triamine (HATATA) or any mixtures thereof. The crosslinking enhancer may be added in an amount of such crosslinking less than 2.0% by weight, for example, less than 1.5% by weight, for example, less than than 1.0% by weight, for example, less than 0.75% by weight, for example, less than 0.5% by weight, and its lower limit is, for example, at least 0.05 % by weight, for example, at least 0.1% by weight, based on the weight of the polymer composition.

[0231] Burn retardants (SR) can, for example, be unsaturated dimers of aromatic alpha-methylalkenyl monomers, such as 2,4-di-phenyl-4-methyl-1-pentene, substituted or unsubstituted diphenylethylene, derivatives of quinone, hydroquinone derivatives, monofunctional vinyl-containing esters and ethers, monocyclic hydrocarbons having at least two or more double bonds or mixtures thereof. For example, the burn retardant can be selected from 2,4-diphenyl-4-methyl-1-pentene, substituted or unsubstituted diphenylethylene, or mixtures thereof.

[0232] The amount of burn retardant may, for example, be greater than or equal to 0.005% by weight, based on the weight of the polymer composition. Furthermore, the amount of burn retardant may, for example, be greater than or equal to 0.01% by weight, greater than or equal to 0.03% by weight, or greater than or equal to 0.04% by weight, based on in the weight of the polymer composition.

[0233] Furthermore, the amount of burn retardant may, for example, be greater than or equal to 2.0% by weight, for example, less than or equal to 1.5% by weight, based on the weight of the burn composition. polymer. Furthermore, the amount of burn retardant may, for example, be less than or equal to 0.8% by weight, less than or equal to 0.75% by weight, less than or equal to 0.70% by weight, or less or equal to 0.60% by weight, based on the weight of the polymer composition. Furthermore, the amount of burn retardant may, for example, be less than or equal to 0.55% by weight, less than or equal to 0.50% by weight, less than or equal to 0.45% by weight, or less or equal to 0.40% by weight, based on the weight of the polymer composition.

[0234] Furthermore, the amount of burn retardant may, for example, be less than or equal to 0.35% by weight, for example, less than or equal to 0.30% by weight, based on the weight of the burn composition. polymer. Furthermore, the amount of burn retardant may, for example, be less than or equal to 0.25% by weight, less than or equal to 0.20% by weight, less than or equal to 0.15% by weight, or less or equal to 0.10% by weight, based on the weight of the polymer composition. Furthermore, the amount of burn retardant may, for example, be less than or equal to 0.15% by weight, or less than or equal to 0.10% by weight, based on the weight of the polymer composition.

[0235] Furthermore, the amount of burn retardant may, for example, be in the range of 0.005 to 2.0% by weight, for example, in the range of 0.005 to 1.5% by weight, based on the weight of the polymer composition. Other exemplified ranges are, for example, 0.01 to 0.8% by weight, 0.03 to 0.75% by weight, 0.03 to 0.70% by weight or 0.04 to 0.60% by weight, based on the weight of the polymer composition. Furthermore, exemplified ranges are, for example, 0.01 to 0.60, to 0.55, to 0.50, to 0.45 or, alternatively, to 0.40% by weight, 0.03 to 0. 0.55 or alternatively 0.50% by weight, 0.03 to 0.45 or alternatively 0.40% by weight, or 0.04 to 0.45 or alternatively 0.40% by weight, based on the weight of the polymer composition.

[0236] Furthermore, burn retardants (SR) can, for example, be selected from graftable stable organic free radicals, as described in document No. EP1699882, which include hindered amine-derived stable organic free radicals: e.g. , hydroxy-derivative of 2,2,6,6-tetramethylpiperidinyloxy (TEMPO), e.g., 4-hydroxy-TEMPO or a bis-TEMPO (e.g., bis(1-oxyl-2,2,6,6-tetramethylpiperidine -4-yl)sebacate), and, for example, multifunctional molecules with at least two nitroxyl groups derived from oxo-TEMPO, 4-hydroxy-TEMPO, an ester of 4-hydroxy-TEMPO, TEMPO bound to the polymer, PROXYL, DOXYL , dimethyl butyl N oxyl, dimethyl diphenylpyrrolidine-1-oxyl or 4-phosphonoxy- TEMPO.

[0237] Graftable stable organic free radicals may be, as described in document No. EP1699882, present in an amount greater than or equal to about 0.005 weight percent, for example, greater than or equal to about 0.01 percent by weight and greater than or equal to about 0.03 weight percent, based on the weight of the polymer composition.

[0238] Furthermore, graftable stable organic free radicals may be, as described in document No. EP1699882, present in an amount less than or equal to about 20.0 weight percent, for example, less than or equal to about 10.0 weight percent, for example, less than or equal to about 5.0 weight percent, based on the weight of the polymer composition.

[0239] Furthermore, graftable stable organic free radicals may be, as described in document No. EP1699882, present in an amount between about 0.005 weight percent and about 20.0 weight percent, for example, between 15 and about 0.01 weight percent and about 10.0 weight percent, for example, between about 0.03 weight percent and about 5.0 weight percent, based on weight of the polymer composition.

[0240] Furthermore, this additional additive (or additives) comprises additive (additives), such as antioxidant (antioxidants), stabilizer (or stabilizers) and/or processing auxiliary (auxiliary). As an antioxidant, sterically hindered or semi-hindered phenol (or phenols), aromatic amine (or amines), aliphatic sterically hindered amine (or amines), organic phosphate (or phosphates), thiocompound (or thiocompounds), and mixtures thereof, can be mentioned. As an additional additive (or additives), flame retardant additive (or additives), water retardant additive (or additives), acid sequestrant (or additives), filler pigment (or pigments) and stabilizer (or stabilizers) ) of voltage can be mentioned.

[0241] Examples of suitable fillers and/or pigments include TiO2, CaCO3, carbon black (e.g., conductive carbon black or “UV carbon black”, i.e., a carbon black that absorbs ultraviolet radiation), auntite, mica, kaolin, aluminum hydroxide (ATH), magnesium dihydroxide (MDH) and SiO2.

[0242] In yet another embodiment, the polymer composition according to the present invention further comprises fillers and/or pigments.

[0243] Furthermore, said fillers and/or pigments may be comprised in the polymer composition according to the present invention in amounts of, for example, 0.01 to 5% by weight, for example, 0.01 to 3 % by weight or, for example, 0.01 to 2% by weight.

[0244] The polymer composition may additionally comprise additional polymer component (or components), including unsaturated polymer (or polymers) and/or polymer (or polymers) that is not unsaturated, wherein the polymer component (or components) is different from said polyethylene.

[0245] The polymer composition can be provided in the form of a powder or pellets in any shape and size, including granules. Pellets can be produced, for example, after polymerization of said polyethylene, in a well-known manner, with the use of conventional pelletizing equipment, such as a pelletizing extruder. The polymer composition may, for example, be supplied in the form of pellets.

[0246] Furthermore, during cross-linking of the polymer composition, decomposition of the cross-linking agent in the polymer composition results in the formation of less than 200 ppm of methane, when measured according to the method for GC analysis, while, when At the same time, a technically desirable level of degree of crosslinking of the polymer composition is maintained when measured according to the method for Hot Determination. The method for GC analysis and the method for Hot Determination are described later in this document in the experimental part under “Determination Methods”.

[0247] An embodiment of the present invention, a polymer composition as described herein, is disclosed, wherein decomposition of the crosslinking agent, during crosslinking of the polymer composition, results in the formation of less than 200 ppm of methane, when measured according to the method for GC Analysis.

[0248] In a further embodiment in accordance with the present invention, a polymer composition, as described herein, is disclosed, in which decomposition of the cross-linking agent results in the formation of less than 190 or 180 ppm of methane.

[0249] An embodiment of the polymer composition according to the present invention, as described herein, is disclosed, in which decomposition of the cross-linking agent results in the formation of less than 170 or 160 ppm of methane.

[0250] A further embodiment of the polymer composition according to the present invention, as described herein, is disclosed, wherein decomposition of the cross-linking agent results in the formation of less than 150 ppm of methane.

[0251] An embodiment of the polymer composition according to the present invention, as described herein, is disclosed, wherein decomposition of the cross-linking agent results in the formation of less than 140, 130, 120, 110 or 100 ppm of methane.

[0252] There is further disclosed an embodiment of the polymer composition according to the present invention, as described herein, in which the decomposition of the cross-linking agent results in the formation of less than 115, 110, 105 or 100 ppm of methane.

[0253] Furthermore, the cross-linked polymer composition has a hot elongation, with a load of 20 N/cm2, which is less than 175% at 200 ° C, when measured on the cross-linked plate sample according to the method for Hot Determination. This method is described in this document further in the part relating to cross-linking and also in the experimental part under “Determination Methods”.

[0254] An embodiment of the polymer composition according to the present invention, as described herein, is disclosed, in which the polymer composition is cross-linked and has a heat elongation, with a load of 20 N/cm2, which is less than 175% when measured according to the Hot Determination method.

[0255] In a further embodiment according to the present invention, the polymer composition as described herein has a heat elongation, with a load of 20 N/cm2, which is less than 170%, or, alternatively , is less than 160%.

[0256] Yet another embodiment of the polymer composition according to the present invention, as described in the present document, is disclosed, in which said hot elongation, with a load of 20 N/cm2, is less than 150%.

[0257] A further embodiment of the polymer composition according to the present invention, as described herein, is disclosed, in which said hot elongation, with a load of 20 N/cm2, is less than 140%.

[0258] Yet a further embodiment of the polymer composition according to the present invention, as described herein, is disclosed, in which said hot elongation, with a load of 20 N/cm2, is less than 130%.

[0259] An even further embodiment of the polymer composition according to the present invention, as described herein, is disclosed, wherein said hot elongation, with a load of 20 N/cm2, is less than 120% , or, alternatively, is less than 110%.

[0260] A further embodiment of the polymer composition according to the present invention, as described herein, is disclosed, wherein the cross-linked polymer composition has a heat elongation, with a load of 20 N/cm2, which is less than 100%.

[0261] An embodiment of the polymer composition according to the present invention, as described herein, is disclosed, wherein the cross-linked polymer composition has a heat elongation, with a load of 20 N/cm2, which is less to 95%, or alternatively, it is less than 90%.

[0262] An embodiment of the polymer composition according to the present invention, as described herein, is disclosed, wherein decomposition of the cross-linking agent results in the formation of less than 150 ppm of methane and the cross-linked polymer composition has a hot elongation, with a load of 20 N/cm2, which is less than 100%.

[0263] A further embodiment of the polymer composition according to the present invention, as described herein, is disclosed, wherein decomposition of the cross-linking agent results in the formation of less than 150 ppm of methane and the polymer composition crosslinked has a hot elongation at a load of 20 N/cm2, which is less than 90%.

POLYMER COMPOSITION POLYETHYLENE

[0264] In embodiments of the polymer composition, polyethylene contains said total amount of vinyl groups consisting of P vinyl groups per 1,000 carbon atoms, as described herein. As described in this document, Pi < P or Pi < P < P2.

[0265] In one embodiment of the polymer composition, the polyethylene contains said total amount of vinyl groups consisting of P vinyl groups per 1,000 carbon atoms.

[0266] In a further embodiment of the polymer composition, the polyethylene contains the total amount of vinyl groups consisting of P, where Pi is 0.88.

[0267] In a particularly preferred embodiment, P1 is 0.89 and P2 is 3.0, even more preferably, P1 is 0.90 and P2 is 1.5.

[0268] In a preferred embodiment, the polymer composition simultaneously satisfies the following:

[0269] P1 ≤ P≤ P2 where P1 is 0.89 and P2 is 3.0;

[0270] Z1 ≤ Z ≤ Z2 where Z1 is 0.15 and Z2 is 0.60; It is

[0271] A1 ≤ A ≤ A2 where A1 is 0.15 and A2 is 3;

[0272] preferably,

[0273] P1 ≤ P ≤ P2 where P1 is 0.9 and P2 is 1.5;

[0274] Z1 ≤ Z ≤ Z2 where Z1 is 0.25 and Z2 is 0.50; It is

[0275] A1 ≤ A ≤ A2 where A1 is 0.60 and A2 is 2.5.

[0276] The “amount of vinyl groups” means in this modality the “total amount of vinyl groups present in the polyethylene”. Polyethylene herein means either a homopolymer, which has been provided with unsaturation by a chain transfer agent, or a copolymer, in which the unsaturation is provided by the polymerization of a monomer together with at least one polyunsaturated comonomer, optionally in the presence of a chain transfer agent and, furthermore, optionally in combination with other comonomers.

[0277] In one embodiment, polyethylene is an unsaturated copolymer which, as already mentioned herein, comprises one or more polyunsaturated comonomers. Furthermore, said vinyl groups (P) present in the unsaturated copolymer can originate from said polyunsaturated comonomer, a polyethylene production process and, optionally, from any chain transfer agent used.

[0278] When the polyethylene of the polymer composition is an unsaturated copolymer comprising at least one polyunsaturated comonomer, then the polyunsaturated comonomer will be a straight carbon chain with at least 8 carbon atoms and at least 4 carbon atoms between unconjugated double bonds, at least one of which is terminal.

[0279] As for polymer materials suitable for the polymer composition, said polyethylene may be any polymer that has relevant features, as defined herein, for the polyethylene of the exemplified polymer composition. Polyethylene can be selected from polyethylene homopolymers as well as polyethylene copolymers with one or more comonomers. Polyethylene can be unimodal or multimodal in relation to molecular weight distribution and/or comonomer distribution, expressions which have a well-known meaning.

[0280] In one embodiment, polyethylene is an ethylene homopolymer.

[0281] In one embodiment of the polymer composition, the polymer composition is obtained by a process comprising ethylene homopolymerization.

[0282] In an exemplified embodiment of the polymer composition, polyethylene is an unsaturated copolymer of polyethylene with at least one polyunsaturated comonomer and, optionally, with one or more other comonomers.

[0283] Said unsaturated polyethylene copolymer is an unsaturated ethylene copolymer.

[0284] In one embodiment of the present invention, there is disclosed a polymer composition, as described herein, wherein the polyethylene is a copolymer of a monomer with at least one polyunsaturated comonomer and with zero, one or more, per example, zero, one, two or three, other comonomers, and wherein said total amount of vinyl groups (B) present in the polymer composition includes vinyl groups originating from said at least one polyunsaturated comonomer, e.g. diene.

[0285] In an exemplified embodiment of the polymer composition, the polymer composition is obtained by a process that comprises blending an ethylene unsaturated copolymer with the crosslinking agent.

[0286] Said ethylene copolymer may be an LDPE copolymer produced in a continuous high pressure polymerization process, in which ethylene is copolymerized with at least one polyunsaturated comonomer and, optionally, with one or more other comonomers, optionally in the presence of a chain transfer agent.

[0287] The optional additional comonomer (or comonomers) present in polyethylene, e.g., ethylene copolymer, is different from the “backbone” monomer and can be selected from an ethylene and alpha-olefin (or alpha-olefins) higher, for example, C3-C20 alpha-olefin (or alpha-olefins), for example, a cyclic alpha-olefin of 5 to 12 carbon atoms or a straight or branched chain alpha-olefin of 3 to 12 carbon atoms, such such as propylene, 1-butene, 1-hexene, 1-nonene or 1-octene, as well as polar comonomer (or polar comonomers).

[0288] In one embodiment, the straight or branched chain alpha-olefin is a straight or branched chain alpha-olefin of 3 to 6 carbon atoms.

[0289] In a further embodiment, the straight-chain alpha-olefin is propylene.

[0290] It is known that, for example, propylene can be used as a comonomer or as a chain transfer agent (CTA), or both, whereby it can contribute to the total amount of vinyl groups in polyethylene, P. Here , when using copolymerizable CTA, such as propylene, the copolymerized CTA to the comonomer content is not calculated.

[0291] In an exemplified embodiment of the polymer composition, the polyethylene is an unsaturated LDPE polymer, for example, an unsaturated LDPE copolymer comprising at least one comonomer that is a polyunsaturated comonomer (referred to herein as a polyunsaturated copolymer). LDPE).

[0292] Furthermore, said polyunsaturated comonomer may be a diene, for example, (1) a diene comprising at least 8 carbon atoms, in which the first carbon-carbon double bond is terminal and in which the second carbon-carbon double bond is unconjugated to the first (group 1 dienes). The exemplified dienes (1) can be selected from C8 to C14 unconjugated dienes or mixtures thereof, for example, selected from 1,7-octadiene, 1,9-decadiene, 1,11-dodecadiene, 1, 13-tetradecadiene, 7-methyl-1,6-octadiene, 9-methyl-1,8-decadiene or mixtures thereof. In a further embodiment, the diene (1) is selected from 1,7-octadiene, 1,9-decadiene, 1,11-dodecadiene, 1,13-tetradecadiene or any mixture thereof.

[0293] A further embodiment in accordance with the present invention of the polymer composition as described herein is disclosed, wherein the polyethylene is a copolymer of a monomer with at least one polyunsaturated comonomer, wherein the polyethylene comonomer - unsaturated is a straight carbon chain with at least 8 carbon atoms and at least 4 carbon atoms between the unconjugated double bonds, at least one of which is terminal, for example, C8 to C14 unconjugated diene, e.g. example, selected from 1,7-octadiene, 1,9-decadiene, 1,11-dodecadiene, 1,13-tetradecadiene or mixtures thereof.

[0294] In a preferred embodiment, polyethylene is a copolymer of ethylene and 1,7-octadiene.

[0295] Yet a further embodiment of the polymer composition according to the present invention, as described herein, is disclosed, wherein the polyethylene is an unsaturated LDPE homopolymer or copolymer produced in a continuous high pressure polymerization process, for example, an ethylene LDPE copolymer with one or more polyunsaturated comonomers and with zero, one or more other comonomers.

[0296] In addition, or as an alternative to the dienes (1) listed herein, the diene can also be selected from other types of polyunsaturated dienes (2), such as from one or more compounds of siloxane with the following formula (group dienes (2)):

[0297] CH2=CH-[SiR1R2-O]n-SiR1R2-CH=CH2,

[0298] where n = 1 to 200, and

[0299] R1 and R2, which may be the same or different, are selected from C1 to C4 alkyl groups and/or C1 to C4 alkoxy groups.

[0300] Furthermore, R1 and/or R2 may, for example, be methyl, methoxy or ethoxy.

[0301] Furthermore, n can, for example, be from 1 to 100, for example, 1 to 50. As an example, divinylsiloxanes, for example, a,w-divinylsiloxane, can be mentioned.

[0302] Exemplified polyunsaturated comonomers for polyethylene are group (1) dienes, as defined herein. The polyethylene may, for example, be a copolymer of ethylene with at least one diene selected from 1,7-octadiene, 1,9-decadiene, 1,11-dodecadiene, 1,13-tetradecadiene or any mixture thereof and , optionally, with one or more other comonomers. It is also exemplified that said polyethylene is the unsaturated LDPE copolymer mentioned herein. It may comprise additional comonomers, for example, polar comonomer (or comonomers), alpha-olefin comonomer (or comonomers), non-polar comonomer (or comonomers) or any mixture thereof.

[0303] As a polar comonomer, the compound (or compounds) that contains hydroxyl group (or groups), alkoxy group (or groups), carbonyl group (or groups), carboxyl group (or groups), ether group (or groups) or ester group (or groups) or a mixture thereof, may be used.

[0304] Furthermore, a non-polar comonomer is a compound (or compounds) that does not contain a hydroxyl group (or groups), alkoxy group (or groups), carbonyl group (or groups), carboxyl group (or groups), carboxyl group (or groups), carboxyl groups, ether group (or groups) or ester group (or groups).

[0305] In a further embodiment, compounds containing carboxyl and/or ester group (or groups) are used and, for example, the compound is selected from the groups of acrylate (or acrylates), methacrylate (or methacrylates) or acetate (or acetates) or any mixtures thereof.

[0306] If present in said unsaturated LDPE copolymer, the polar comonomer may, for example, be selected from the group of alkyl acrylates, alkyl methacrylates or vinyl acetate, or a mixture thereof. Furthermore, said polar comonomers can, for example, be selected from C1 to C6 alkyl acrylates, C1 to C6 alkyl methacrylates and vinyl acetate. Furthermore, said polar copolymer comprises a copolymer of ethylene with C1 to C4 alkyl acrylate, such as methyl, ethyl, propyl or butyl acrylate, or vinyl acetate, or any mixture thereof.

[0307] Polyethylene, from the polymer composition described herein, can be prepared using any conventional polymerization process and equipment, the conventional means described herein for providing unsaturation, and any conventional means for adjusting the MFR2, the in order to control and adjust process conditions to achieve a desired balance between MFR2 and the amount of vinyl groups in the polymerized polymer. The unsaturated LDPE polymer as defined herein, for example, the unsaturated LDPE copolymer, of the polymer composition is produced in a continuous high-pressure reactor by free radical-initiated polymerization (called high-pressure radical polymerization). Usable high pressure (HP) polymerization and adjustment of process conditions are well known and described in the literature and can be easily used by a skilled person to provide the inventive balance described herein. Continuous high-pressure polymerization can be carried out in a tubular reactor or in an autoclave, e.g. in a tubular reactor. An embodiment of a continuous HP process is described herein for polymerizing ethylene optionally together with one or more comonomers, for example, with at least one or more polyunsaturated comonomers, in a tubular reactor to obtain an LDPE homopolymer or copolymer. , as defined in this document. The process can also be adapted to other polymers.

[0308] Furthermore, polyethylene, of the polymer composition described herein, can be produced in a high pressure reactor by free radical polymerization (called high pressure radical polymerization). Free radical-initiated polymerization is very rapid and is therefore well suited to a continuous process, in which careful control of process parameters can be achieved by continuous monitoring and adjustments. For the high pressure radical polymerization process, there is a continuous feed of ethylene and initiator. The high pressure radical polymerization process is preferably an autoclave or tubular process, more preferably a tubular reactor. A high-pressure tubular process typically produces a polyethylene with a narrower molecular weight distribution and with a lower degree of long-chain branching and other branching structure compared to a polyethylene produced in an autoclave process, if process conditions are used, such as similar temperature profile, similar pressure and similar initiator feed. Typically, a tubular reactor also has more favorable production economics because it has higher ethylene conversion rates.

[0309] In a further embodiment, the polyethylene of the polymer composition of the present invention is produced in a continuous high pressure tubular reactor.

COMPRESSION:

[0310] Ethylene is fed to a compressor primarily to allow handling of large quantities of ethylene at controlled pressure and temperature. Compressors are generally piston compressor or diaphragm compressors. The compressor is generally a series of compressors that can work in series or in parallel. Most common are 2 to 5 compression steps. Ethylene and recycled comonomers can be added at possible points depending on pressure. The temperature is typically low, generally in the range of less than 200°C or less than 100°C. Said temperature may, for example, be lower than 200 °C.

TUBULAR REACTOR:

[0311] The mixture is fed to the tubular reactor. The first part of the tube is to adjust the temperature of the ethylene fed; the usual temperature is 150 to 170 °C. Then the radical initiator is added. As a radical initiator, any compound or a mixture thereof that decomposes into radicals at an elevated temperature can be used. Usable radical initiators are commercially available. The polymerization reaction is exothermic. There may be several radical initiator injection points, for example, 1 to 5 points, usually equipped with separate injection pumps. Furthermore, ethylene and optional comonomer (or comonomers) can be added at any time during the process, in any zone of the tubular reactor and/or from one or more known injection points. The reactor is cooled continuously, for example by water or steam. The highest temperature is called the peak temperature and the lowest temperature is called the radical initiator temperature. The "lowest temperature" herein means the initial reaction temperature which is called the initiation temperature that is "lowest", as is evident to a person skilled in the art.

[0312] Suitable temperatures are in the range of 80 to 350 °C and pressure of 100 to 400 MPa. Pressure can be measured at least in the compression stage and after the tube. Temperature can be measured at multiple points during all stages. High temperature and high pressure generally increase yield. The use of various temperature profiles selected by a person skilled in the art will allow control of polymer chain structure, i.e., Long Chain Branching and/or Short Chain Branching, density, MFR, viscosity, Molecular Weight Distribution, etc.

[0313] The reactor conventionally ends with a valve. The valve regulates the reactor pressure and depressurizes the reaction mixture from reaction pressure to separation pressure.

SEPARATION:

[0314] The pressure is typically reduced to approximately 10 to 45 MPa, for example, to approximately 30 to 45 MPa. The polymer is separated from unreacted products, e.g., gaseous products such as optional monomers or comonomers, and most of the unreacted products are recovered. Typically, low molecular compounds, i.e. wax, are removed from the gas. Pressure can also be reduced to recover and recycle unused gaseous products, such as ethylene. The gas is usually cooled and cleaned before recycling.

[0315] Next, the melted polymer obtained is normally mixed and pelletized. Optionally, or in some embodiments, additives can be added to the mixer. Additional details of the production of ethylene (co)polymers by high-pressure radical polymerization can be found in the Encyclopedia of Polymer Science and Engineering, Vol. 6 (1986), pages 383 to 410.

[0316] The MFR2 of polyethylene, for example, LDPE copolymer, can be adjusted by using, for example, chain transfer agent during polymerization and/or by adjusting the reaction temperature or pressure.

[0317] When the LDPE copolymer of the invention is prepared, then, as is well known, the amount of vinyl groups can be adjusted by polymerizing ethylene, for example, in the presence of one or more polyunsaturated comonomers, agent (or chain transfer agents), or both, using the desired feed ratio between C2 and polyunsaturated comonomer and/or chain transfer agent, depending on the nature and amount of carbon-carbon double bonds desired for the polyunsaturated copolymer. LDPE. A.I. Document No. WO 9308222 describes a high pressure radical polymerization of ethylene with polyunsaturated monomers, such as α,w-alkadienes, to increase the unsaturation of an ethylene copolymer. The unreacted double bond (or bonds) thus provides pendant vinyl groups to the polymer chain formed at the site into which the polyunsaturated comonomer was incorporated by polymerization. As a result, unsaturation can be distributed evenly along the polymer chain in a random copolymerization manner. Furthermore, for example, document No. WO 9635732 describes high pressure radical polymerization of ethylene and a certain type of polyunsaturated α,w-divinylsiloxanes. Furthermore, as is known, for example, propylene can be used as a chain transfer agent to provide double bonds, whereby it can also be partially copolymerized with ethylene.

[0318] The alternative unsaturated LDPE homopolymer can be produced in a manner analogous to the process conditions described herein as the unsaturated LDPE copolymer, with the exception that ethylene is polymerized in the presence of a chain transfer agent only.

[0319] An exemplified polyethylene, for example, of the LDPE copolymer, of the present invention may have a density, when measured in the polyethylene according to ISO 1183-1 method A: 2012, of, for example, more than 0.860 g /cm3, more than 0.870, more than 0.880, more than 0.885, more than 0.890, more than 0.895, more than 0.900, more than 0.905, more than 0.910 or more than 0.915 g/cm3 .

[0320] Another exemplified polyethylene, for example, the LDPE copolymer, of the present invention may have a density, when measured in polyethylene according to ISO 1183-1 method A: 2012, of up to 0.960 g/cm3, less than 0.955, less than 0.950, less than 0.945, less than 0.940, less than 0.935 or less than 0.930 g/cm3.

[0321] In a further embodiment the density range, when measured in polyethylene according to ISO 1183-1 method A: 2012, is 0.915 to 0.930 g/cm3.

[0322] Furthermore, said unsaturated copolymer, for example, LDPE copolymer, of the polymer composition comprises comonomer (or comonomers) in a total amount of up to 45% by weight, for example, from 0.05 to 25% by weight, or for example from 0.1 to 15% by weight, based on the amount of polyethylene.

[0323] An exemplified polyethylene of the polymer composition is crosslinkable.

[0324] In an exemplified embodiment, the polymer composition consists of at least one polyethylene. The polymer composition may comprise additional components, such as additives described herein, which may be added to a mixture with a carrier polymer, i.e., in the so-called master batch.

[0325] In a further embodiment, the polymer composition may comprise polyethylene, as described herein, together with the crosslinking agent and together with 0, 1, 2, 3, 4, 5, 6 or more additives, and wherein the polymer composition is in the form of pellets.

[0326] A further embodiment of the present invention discloses a process for producing a polymer composition, as described herein, wherein the process comprises blending polyethylene with the crosslinking agent.

END APPLICATIONS

[0327] One embodiment of the present invention provides an article obtained from a process comprising the use of a polymer composition as described herein, wherein the article is, for example, a cable, e.g. food.

[0328] A further embodiment of the present invention provides an article, which is obtained from a process comprising the use of the polymer composition, as described herein.

[0329] Yet a further embodiment of the present invention provides an article comprising layer (or layers), e.g., insulating layer (or layers), which is obtained from a polymer composition, as described herein, wherein the article is, for example, a cable, e.g. a power cord.

[0330] In one embodiment of the present invention, an article, for example, a cable, is provided, wherein the cable, for example, the power cable, comprises a layer that is obtained from said polymer composition.

[0331] In a further embodiment of the present invention, an article is provided, wherein said article is crosslinkable and is obtained from a process comprising the use of the polymer composition, as described herein.

[0332] In yet a further embodiment of the present invention, an article is provided, said article comprising the polymer composition as described herein.

[0333] In a further embodiment of the present invention, an article is provided, wherein said article is cross-linked and is obtained from a process comprising the use of the polymer composition, as described herein.

[0334] A further embodiment of the present invention provides an article, which is a cable, for example, a power cord.

[0335] Furthermore, the invention is highly suitable for W&C applications, whereby an article is, for example, a cable, which is crosslinkable and comprises one or more layers, wherein at least one layer is obtained from the composition polymer, as described in this document.

[0336] Furthermore, a further embodiment of the present invention is provided, wherein said at least one layer comprises the polymer composition as described herein.

[0337] A further embodiment of the present invention provides a power cable comprising layer (or layers), e.g., insulating layer (or layers), which is obtained from the polymer composition as described herein.

[0338] A further embodiment of the present invention is provided, wherein said article is an AC power cord.

[0339] A further embodiment of the present invention is provided wherein said article is a DC power cable.

[0340] Furthermore, at least one layer of the cable obtained from the polymer composition may, for example, be an insulation layer.

[0341] Furthermore, at least one layer of the cable comprising the polymer composition may, for example, be an insulation layer.

[0342] Furthermore, the cable of the present invention may, for example, be a power cable comprising at least one inner semiconductor layer, an insulation layer and an outer semiconductor layer in a determined order, wherein at least the layer insulation is obtained from the polymer composition as described herein.

[0343] Furthermore, a further embodiment of the present invention is provided, in which the expression “is obtained from the polymer composition” also comprises the feature “comprises the polymer composition”.

[0344] Power cord herein means a power-transferring cord that operates at any voltage. The voltage applied to the power cord can be AC, DC, or transient (impulse). In one embodiment, the multilayer article is a power cable that operates at voltages greater than 6 kV.

[0345] A further embodiment of the present invention discloses a process for producing an article, as described herein, which process comprises the use of a polymer composition, as described herein.

[0346] Furthermore, the invention provides a process for producing the article described in the present document, which comprises the steps of a) forming an article, wherein the process comprises the polymer composition, as described in the present document. Said process may, for example, comprise at least the steps of

[0347] a0) mixing a polymer composition, as described herein, optionally, together with additional component (or components), and

[0348] a) forming a cable obtained from the polymer composition, as described in this document.

[0349] An additional embodiment describes the formation of a cable comprising the polymer composition as described herein.

[0350] “Melting mixing” is a well-known blending method in which the polymer component (or components) is mixed at an elevated temperature, which is typically higher, for example, at least 20 to 25 °C. above the melting or softening point of polymer component (or components).

[0351] In one embodiment, a cable is produced, comprising a conductor surrounded by one or more layers, wherein the process comprises a step of a) applying to a conductor the polymer composition, as described herein, to form at least one of said layers surrounding the conductor.

[0352] Thus, in step (a) at least one layer of said one or more layers is applied and obtained by using the polymer composition, as described herein.

[0353] The cable production process exemplified in the present document can also, for example, comprise at least two processing steps

[0354] a0) mixing said polymer composition, as described herein, optionally, together with additional component (or components) and then,

[0355] a) applying the melt mixture obtained in step a0) to a conductor to form at least one layer.

[0356] The polymer composition, as described herein, can be introduced in step a0) of the process, for example, in the form of pellets and mixing, that is, melt mixing, is carried out at an elevated temperature which melts (or softens) the polymer material to allow it to be processed.

[0357] Furthermore, layers can, for example, be a) applied by (co)extrusion. The term “(co)extrusion” in this document means that, in the case of two or more layers, said layers can be extruded in separate steps, or at least two or all of said layers can be coextruded in the same extrusion step. , as is well known in the art.

[0358] In an exemplified embodiment, the crosslinkable polymer composition may comprise a crosslinking agent before the polymer composition is used for the production of cables, wherein the polyethylene and the crosslinking agent may be blended by any mixing process conventional, for example, by adding the crosslinking agent to a melt of a polymer composition, for example, in an extruder, as well as by adsorption of liquid peroxide, peroxide in liquid form or peroxide dissolved in a solvent onto a solid composition of polymer, e.g. pellets thereof. Alternatively in this embodiment, the polyethylene and the crosslinking agent can be mixed by any conventional mixing process. Exemplary mixing procedures include melt mixing, for example, in an extruder, as well as adsorption of liquid peroxide, peroxide in liquid form or a peroxide dissolved in a solvent of a polymer composition or pellets thereof. The polymer composition obtained from components, for example, polyethylene and the crosslinking agent, is then used for an article preparation process, for example, a cable.

[0359] In another embodiment, the crosslinking agent can be added, for example, in step a0) during the preparation of the crosslinkable article, and also forms the polymer composition of the present invention. When the crosslinking agent is added during the article preparation process, then, for example, the crosslinking agent as described herein will be added in a liquid form at room temperature or will be preheated above its melting point or dissolved in a carrier medium, as is well known in the art.

[0360] The polymer composition of the present invention may also comprise another additive (or additives), or additional additive (or additives) may be mixed into the polymer composition during a process of preparing an article comprising the polymer composition.

[0361] Consequently, the process of the invention may, for example, comprise the steps of

[0362] - a00) providing said step a0) of said polymer composition, as described herein, which comprises

[0363] at least one polyethylene, and

[0364] a crosslinking agent,

[0365] - a0) mixing the polymer composition optionally together with additional components, and

[0366] a) applying the melt mixture obtained in step a0) to a conductor to form at least one of said one or more layers of cables.

[0367] Alternatively, the process of the invention comprises the steps of

[0368] - a00) providing said step a0) of said polymer composition, as described herein, which comprises

[0369] at least one polyethylene,

[0370] - a00') adding at least one crosslinking agent to said polymer composition,

[0371] - a0) mixing the polymer composition and the crosslinking agent, optionally, together with additional components, and

[0372] - a) applying the fusion mixture obtained in step a0) to a conductor to form at least one of said one or more layers of cables.

[0373] In the exemplified process, the melt mixing a0) of the polymer composition alone is carried out in a mixer or extruder, or in any combination thereof, at elevated temperature and, if the crosslinking agent is present, also below the temperature crosslinking used later. After melt mixing of a0), for example, in said extruder, the material resulting from the melt mixed layer is then, for example, a) (co)extruded into a conductor in a manner well known in the field. Mixers and extruders, such as single or twin screw extruders, which are conventionally used for preparing cables, are suitable for the process of the invention.

[0374] The exemplified embodiment of the process provides for the preparation of a crosslinkable cable, for example, a crosslinkable power cable, wherein the process comprises an additional step of b) crosslinking the at least one layer of cable obtained in step a) which comprises a crosslinkable polyethylene polymer composition, wherein the crosslinking is carried out in the presence of a crosslinking agent, for example, a peroxide.

[0375] It is understood and well known that also the other cable layers and materials thereof, if present, can be crosslinked at the same time, if desired.

[0376] Cross-linking may be carried out under cross-linking conditions, typically by increased temperature treatment, e.g., at a temperature above 140°C, e.g., above 150°C, such as in the range of 160 to 350° C, depending on the cross-linking agent used well-known in the field. Typically, the crosslinking temperature is at least 20 ° C higher than the temperature used in the mixing step a0) and can be estimated by a person skilled in the art.

[0377] As a result, a cross-linked cable is obtained that comprises at least one cross-linked layer of the polymeric composition of the invention.

[0378] In a further embodiment according to the present invention, a polymer composition is disclosed, in which said total amount of vinyl groups, B, originates from (alongside vinyl groups originating from polymerization initiated by free radicals):

[0379] i) polyunsaturated comonomer (or comonomers),

[0380] ii) chain transfer agent (or agents),

[0381] iii) low molecular weight unsaturated compound (or compounds), for example, crosslinking reinforcer (or reinforcers) and/or burn retardant (or retardants), or

[0382] iv) any mixture of (i) to (iii).

[0383] In general, “vinyl group” in this document means chemical moiety of CH2=CH- which may be present in any of i) to iv).

[0384] The i) polyunsaturated comonomers and ii) chain transfer agents are described herein in relation to the polyethylene of the polymer composition according to the present invention.

[0385] The iii) low molecular weight compound (or compounds), if present, can be added to the polymer composition.

[0386] Furthermore, the iii) low molecular weight compound (or compounds) can, for example, be a crosslinking reinforcer (or reinforcers) that can also contribute to said total amount of vinyl groups, B, of the composition of polymer. The cross-linking enhancer may be, for example, a compound (or compounds) that contains at least 2 unsaturated groups, such as an aliphatic or aromatic compound, an ester, an ether or a ketone, which contains at least 2 unsaturated groups, such as a cyanurate, an isocyanurate, a phosphate, an orthoformate, an aliphatic or aromatic ether or an allyl ester of benzene tricarboxylic acid. Examples of esters, ethers, amines and ketones are compounds selected from the general groups of diacrylates, triacrylates, tetraacrylates, triallylcyanurate, triallylisocyanurate, 3,9-divinyl-2,4,8,10-tetra-oxaspiro[5, 5]-undecane (DVS), triallyl trimellitate (TATM) or N,N,N',N',N",N”-hexa-allyl-1,3,5-triazine-2,4,6-triamine (HATATA) or any mixtures thereof. The crosslinking enhancer may be added in an amount of such crosslinking less than 2.0% by weight, for example, less than 1.5% by weight, for example, less than than 1.0% by weight, for example, less than 0.75% by weight, for example, less than 0.5% by weight, and its lower limit is, for example, at least 0.05% by weight, for example, at least 0.1% by weight, based on the weight of the polymer composition.

[0387] Furthermore, the iii) low molecular weight compound (or compounds) can, for example, be burn retardant (or retardants) (SR) which can also contribute to said total amount of vinyl groups, B, of the polymer composition.

[0388] Burn retardants (SR) can, for example, be, as already described herein, unsaturated dimers of aromatic alpha-methylalkenyl monomers, such as 2,4-di-phenyl-4-methyl-1-pentene , substituted or unsubstituted diphenylethylene, quinone derivatives, hydroquinone derivatives, esters and ethers containing monofunctional vinyl, monocyclic hydrocarbons with at least two or more double bonds or mixtures thereof. For example, the burn retardant may be selected from 2,4-diphenyl-4-methyl-1-pentene, substituted or unsubstituted diphenylethylene, or mixtures thereof.

[0389] The amount of burn retardant may, for example, be greater than or equal to 0.005% by weight, based on the weight of the polymer composition. Furthermore, the amount of burn retardant may, for example, be greater than or equal to 0.01% by weight, greater than or equal to 0.03% by weight, or greater than or equal to 0.04% by weight, based on in the weight of the polymer composition.

[0390] Furthermore, the amount of burn retardant may, for example, be greater than or equal to 2.0% by weight, for example, less than or equal to 1.5% by weight, based on the weight of the burn composition. polymer. Furthermore, the amount of burn retardant may, for example, be less than or equal to 0.8% by weight, less than or equal to 0.75% by weight, less than or equal to 0.70% by weight, or less or equal to 0.60% by weight, based on the weight of the polymer composition. Furthermore, the amount of burn retardant may, for example, be less than or equal to 0.55% by weight, less than or equal to 0.50% by weight, less than or equal to 0.45% by weight, or less or equal to 0.40% by weight, based on the weight of the polymer composition.

[0391] Furthermore, the amount of burn retardant may, for example, be less than or equal to 0.35% by weight, for example, less than or equal to 0.30% by weight, based on the weight of the burn composition. polymer. Furthermore, the amount of burn retardant may, for example, be less than or equal to 0.25% by weight, less than or equal to 0.20% by weight, less than or equal to 0.15% by weight, or less or equal to 0.10% by weight, based on the weight of the polymer composition. Furthermore, the amount of burn retardant may, for example, be less than or equal to 0.15% by weight, or less than or equal to 0.10% by weight, based on the weight of the polymer composition.

[0392] Furthermore, the amount of burn retardant may, for example, be in the range of 0.005 to 2.0% by weight, for example, in the range of 0.005 to 1.5% by weight, based on the weight of the polymer composition. Other exemplified ranges are, for example, 0.01 to 0.8% by weight, 0.03 to 0.75% by weight, 0.03 to 0.70% by weight or 0.04 to 0.60% by weight, based on the weight of the polymer composition. Furthermore, exemplified ranges are, for example, 0.01 to 0.60, to 0.55, to 0.50, to 0.45 or, alternatively, to 0.40% by weight, 0.03 to 0. 0.55 or alternatively 0.50% by weight, 0.03 to 0.45 or alternatively 0.40% by weight, or 0.04 to 0.45 or alternatively 0.40% by weight, based on the weight of the polymer composition.

[0393] Furthermore, burn retardants (SR) can, for example, also be selected from graftable stable organic free radicals, as described in document No. EP1699882 and as also already described in this document.

[0394] The polyethylene of the polymer composition may, for example, be a copolymer of monomer units with units of at least one unsaturated comonomer (or comonomers) and zero, one, two or three other comonomers, and comprises at least vinyl groups which originate from the polyunsaturated comonomer.

[0395] Furthermore, the polyethylene of the polymer composition may comprise about 0.05 to about 0.10 vinyl groups per 1,000 carbon atoms (C atoms) that originate from free radical-initiated polymerization.

[0396] In accordance with the present invention, each feature in any of the embodiments disclosed herein, in any category of the present invention, may be freely combined with any feature of any of the other embodiments disclosed herein.

DETERMINATION METHODS

[0397] Unless otherwise indicated in the description or in the experimental part, the following methods were used for property determinations.

MELT FLOW RATE

[0398] The melt flow rate (MFR) is determined according to the ISO 1133-1:2011 method and is indicated in g/10 min. The MFR is an indication of the fluidity and therefore the processability of the polymer, here polyethylene, or the polymer composition. The higher the melt flow rate, the lower the viscosity of the polymer or polymer composition. MFR is determined at 190 °C for polyethylenes and can be determined at different loads, such as 2.16 kg (MFR2) or 21.6 kg (MFR21).

DENSITY

[0399] Density is measured in the polymer, that is, in polyethylene, in accordance with ISO 1183-1, method A:2012. Sample preparation is done by compression molding in accordance with ISO 178552:2016.

ASTM D3124-98 AND ASTM D6248-98 METHODS FOR DETERMINING THE AMOUNT OF DOUBLE BONDS IN THE POLYMER COMPOSITION OR IN THE POLYMER, THAT IS, IN POLYETHYLENE

[0400] The ASTM D6248-98 method applies to the determination of double bonds in both polymer composition and polyethylene. The determination of double bonds of the polymeric composition is made on the polyethylene (to determine the P parameter) or, alternatively, on the polymer composition (to determine the B parameter). The polymer composition and the polyethylene are hereinafter referred to in this method description as “the composition” and “the polymer”, respectively.

[0401] The ASTM D3124-98 and ASTM D624898 methods include, on the one hand, a procedure for determining the number of double bonds/1,000 C atoms, which is based on the ASTM D312498 method. In ASTM D3124-98 method, a detailed description is provided for the determination of vinylidene groups/1000 C atoms based on 2,3-dimethyl-1,3-butadiene. In the ASTM D6248-98 method, detailed descriptions for the determination of vinyl and trans-vinylene groups/1,000 C atoms are provided based on 1-octene and trans-3-hexene, respectively. The sample preparation procedure described herein was applied herein to the determination of vinyl groups/1,000 C atoms and trans-vinylene groups/1,000 C atoms in the present invention. The ASTM D6248-98 method suggests possible inclusion of the bromination procedure of the ASTM D3124-98 method, but the samples in relation to the present invention were not brominated. It was demonstrated that the determination of vinyl groups/1,000 C atoms and trans-vinylene groups/1,000 C atoms can be done without significant interference, even without subtraction of spectra of brominated samples. To determine the extinction coefficient for these two types of double bonds, the following two compounds were used: 1-decene for vinyl and trans-4-decene for trans-vinylene, and the procedure described in ASTM-D6248-98 was followed above mentioned exception.

[0402] The total amount of vinyl bonds, vinylidene bonds and trans-vinylene double bonds of the “polymer” was analyzed using IR spectrometry and given as the amount of vinyl bonds, vinylidene bonds and trans-vinylene bonds. vinylene per 1,000 carbon atoms.

[0403] Furthermore, the total amount of vinyl and trans-vinylene double bonds of the “composition”, with a possible contribution of double bonds from any low molecular weight unsaturated compound used (iii), can also be analyzed by means of IR spectroscopy is given as the amount of vinyl bonds, vinylidene bonds, and trans-vinylene bonds per 1,000 carbon atoms.

[0404] The composition or polymer to be analyzed was pressed into thin films with a thickness of 0.5 to 1.0 mm. The actual thickness was measured. FT-IR analysis was performed on a Perkin Elmer Spectrum One. Two scans were recorded with a resolution of 4 cm-1.

[0405] A baseline was drawn from 980 cm-1 to about 840 cm-1. The maximum peaks were determined at around 910 cm-1 for vinyl and around 965 cm-1 for trans-vinylene. The number of double bonds/1,000 carbon atoms was calculated using the following formulas:

[0406] vinyl/1,000 atoms of C = (14 x Abs)/(13.13 x L x D)

[0407] trans-vinylene/1,000 atoms of C = (14 x Abs)/(15.14 x L x D)

[0408] where

[0409] Abs: absorbance (peak height)

[0410] L: film thickness in mm

[0411] D: material density (g/cm3)

[0412] The molar absorption capacity, ε, that is, 13.13 and 15.14, respectively, in the above calculations was determined as Hmol- 1wm-1 through:

[0413] ε = Abs / (L x W)

[0414] where Abs is the maximum absorbance defined as peak height, C the concentration (moH-1) and L the cell thickness (mm).

[0415] ASTM D3124-98 and ASTM D624898 methods, on the other hand, also include a procedure for determining the molar extinction coefficient. At least three 0.18 moH-1 solutions in carbon disulfide (CS2) were used and the average value of the molar extinction coefficient used.

[0416] The amount of vinyl groups originating from the polyunsaturated comonomer per 1,000 carbon atoms was determined and calculated as follows:

[0417] The polymer to be analyzed and a reference polymer were produced in the same reactor, basically using the same conditions, that is, similar peak temperatures, pressure and production rate, but with the only difference that the comonomer polyunsaturated is added to the polymer to be analyzed and not added to the reference polymer. The total amount of vinyl groups of each polymer was determined by FT-IR measurements, as described herein. It is then assumed that the base level of vinyl groups, i.e. those formed by the process and from chain transfer agents that result in vinyl groups (if present), is the same for the reference polymer and the polymer to be analyzed with the only exception that in the polymer to be analyzed a polyunsaturated comonomer is also added to the reactor. This base level is then subtracted from the measured quantity of vinyl groups in the polymer to be analyzed, thus resulting in the quantity of vinyl groups/1,000 C atoms, which result from the polyunsaturated comonomer.

[0418] Methods ASTM D3124-98 and ASTM D624898 include a calibration procedure for measuring the double bond content of a low molecular weight unsaturated compound (iii), if present (referred to below as Compound)

[0419] The molar absorption capacity of the Compound (for example, a crosslinking reinforcer or a burn retardant compound, as exemplified in the description) can be determined with said methods according to ASTM D6248-98. At least three solutions of the Compound in CS2 (carbon disulfide) are prepared. The concentrations used of the solutions are close to 0.18 mol/l. The solutions are analyzed with FTIV and scanned at 4 cm-1 resolution in a liquid cell with a path length of 0.1 mm. The maximum intensity of the absorbance peak that refers to the unsaturated portion of the Compound (or Compounds) (each type of carbon-carbon double bond present) is measured.

[0420] The molar absorption capacity, ε, in l»mo|- ’•mm’1 for each solution and type of double bond is calculated using the following equation:

[0421] ε = (1/CL) x Abs

[0422] C = concentration of each type of carbon-carbon double bond to be measured, mol/l

[0423] L = cell thickness in mm

[0424] Abs = maximum absorbance (peak height) of the peak of each type of carbon-carbon double bond to be measured, mol/l.

[0425] The average molar absorption capacity, ε, for each type of double bond is calculated.

[0426] Additionally, the average molar absorption capacity, ε, of each type of carbon-carbon double bond can then be used to calculate the concentration of double bonds in the reference polymer and in the polymer samples to be analyzed. .

DYNAMIC RHEOLOGY METHOD (VISCOSITY) ISO 6721-1:

[0427] The dynamic rheological properties of the polymer, here polyethylene, or the polymer composition (also measured on polyethylene) can be determined using a controlled stress rheometer, using a parallel plate geometry (25 mm in diameter) and a gap of 1.8 mm between the top and bottom plates. Before testing, samples need to be stabilized by dry blend pellets together with Irganox B225 at 0.25 to 0.3%. Irganox B 225 is a mixture of 50% Irganox 1010, Pentaerythritol tetrakis(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate), CAS no. 6683-19-8 and 50% Irgafos 168, Tris(2,4-di-tert-butylphenyl) phosphite, CAS No. 31570-04-4. Note that adding an antioxidant, here Irganox B225, is normally not the standard procedure of the ISO 6721-1 method.

[0428] The frequency sweep test, that is, the “Dynamic Rheology (Viscosity) method”, was carried out according to the ISO standard method, ISO 6721-1, with an angular frequency range of 500 to 0, 02 rad/s. All experiments were conducted under a nitrogen atmosphere at a constant temperature of 190 °C and tension in the linear viscoelastic region. During the analysis, the storage modulus (G'), the loss modulus (G”), the complex modulus (G*) and the complex viscosity (n*) were recorded and plotted as a function of frequency (w). The measured values of complex viscosity (n*) at angular frequency of 0.05, 100 and 300 rad/s are obtained from the test. The abbreviations for these parameters are !θ.!#, !%!! and !θ!!, respectively.

[0429] The zero viscosity value n*0 is calculated using the Carreau-Yasuda model. For cases where the use of this model for estimating zero shear viscosity is not recommended, a rotational shear test at low shear rate is performed. This test is limited to a shear rate of 0.001 to 1 s-1 and a temperature of 190 °C.

PREPARATION OF THE CROSS-CROSS PLATE, THAT IS, THE METHOD FOR CROSS-CROSSING THE PLATE: PREPARATION OF CROSS-CLICKED PLATE WHEN USING DICUMYL PEROXIDE (DCP) OR TERC-BUTYLCUMYL-PEROXIDE (TBCP) AS PEROXIDE, THAT IS, THE PLATE CROSS-CROSS-CLICKING METHOD

[0430] The cross-linked plate is prepared from pellets of the test polymer composition, that is, the polymer composition according to the present invention and the comparative polymer composition, which have been compression molded using the following conditions: First , the pellets are melted at 120 °C for 1 min under a pressure of 61 N/cm2. Then, the temperature is increased to 180 °C at a speed of 18 K/min and at the same time, the pressure is increased to 614 N/cm2. The temperature is maintained at 180 °C for 10 min. The plates then become cross-linked using the peroxide present in the polymer composition. The total cross-linking time is 14 minutes, which includes the time to increase the temperature from 120 to 180 °C. After cross-linking is complete, the cross-linked plates, i.e. the cross-linked polymer composition according to the present invention and the comparative polymer composition, are cooled to room temperature with a cooling rate 15 K/min while still under pressure. The final thickness of the plates is 1.5 mm.

PREPARATION OF CROSS-CLICKED PLATE WHEN USING 2,5-DIMETHYL-2,5-DI (TERT-BUTYLPEROXY)HEXYNE-3, I.E., TRIGONOX® 145- E85, (T145E85) AS PEROXIDE, I.E., THE METHOD OF CROSS-CLICKING PLATE

[0431] The cross-linked plate is prepared from pellets of the test polymer composition, that is, the polymer composition according to the present invention and the comparative polymer composition, which have been compression molded using the following conditions: First , the pellets are melted at 120 °C for 1 min under a pressure of 61 N/cm2. Then, the temperature is increased to 180 °C at a speed of 18 K/min and at the same time, the pressure is increased to 614 N/cm2. The temperature is maintained at 180 °C for 20 min. The plates then become cross-linked using the peroxide present in the polymer composition. The total cross-linking time is 24 minutes, which includes the time to increase the temperature from 120 to 180 °C. After cross-linking is complete, the cross-linked plates, i.e. the cross-linked polymer composition according to the present invention and the comparative polymer composition, are cooled to room temperature with a cooling rate 15 K/min while still under pressure. The final thickness of the plates is 1.5 mm.

GAS CHROMATOGRAPHY (GC) - ANALYSIS PROTOCOL, THAT IS, THE METHOD FOR GC ANALYSIS GC ANALYSIS PROTOCOL (PLATE), THAT IS, THE METHOD FOR GC ANALYSIS

[0432] The content of peroxide decomposition products, herein methane (CH4), is given in ppm (weight) and is determined by gas chromatography (GC) from a cross-linked sample of the polymer composition in accordance with the present invention and the comparative polymer composition. Said cross-linking was carried out as described in the method for cross-linking the plate.

[0433] A sample specimen with a thickness of 1.5 mm and a weight of 1 g is cut in the middle of the cross-linked plate, that is, the cross-linked polymer composition according to the present invention and the comparative cross-linked polymer composition, immediately after completion of the cross-linking step (i.e., in the method for cross-linking the plate). The obtained sample is placed in a 120 ml headspace vial with an aluminum crimp cup with Teflon seal and heat treated at 60 °C for 1.5 h to equilibrate any gaseous volatiles present in said sample. Then, 0.2 ml of the gas captured in the sample bottle is injected into the gas chromatograph, where the presence and content of the volatiles, for example methane, that are to be measured are analyzed. Dual samples are analyzed and the reported methane content value is an average of both analyses. The instrument used in this document was an Agilent GC 7890A with an Al2O3/Na2SO4 - column with dimensions 0.53 mm x 50 m and a film thickness of 10 μm, supplied by Plot Ultimetal. Helium was used as the carrier gas and FID detection was used.

HOT DETERMINATION METHOD HOT METHOD FOR SAMPLING CROSS-CROSSED PLATES

[0434] Hot elongation, as well as permanent deformation, were determined on samples taken from cross-linked plates, that is, from the cross-linked polymer composition according to the present invention and from the cross-linked comparative polymer composition. These properties were determined in accordance with IEC 60811-507:2012. In the hot test, a dumbbell made of the tested material is equipped with a weight corresponding to 20 N/cm2. First of all, the specimen is marked with reference lines. In the middle of the specimen, two reference lines are made (one on each side). The distance between the two lines, L0 is 20 mm. This specimen is placed in an oven at 200 °C with a weight corresponding to 20 N/cm2 and, after 15 minutes, the hot elongation is measured as follows. The distance between the reference lines after 15 minutes at 200 °C is called L1 and is measured. Elongation after 15 minutes is calculated as follows: hot elongation (%) = ((L1*100)/L0)-100. Subsequently, the weight is removed and the sample is left to rest for 5 minutes at 200 °C. Then the sample is removed from the oven and cooled to room temperature. After cooling, the distance L2 between the 2 reference lines is measured and the permanent deformation is calculated as follows: permanent deformation (%) = (L2*100)/L0)-100.

[0435] Cross-linked plates were prepared as described in Cross-linked plate preparation, that is, the method for cross-linking the plate, and dumbbell specimens are prepared from a 1.5 mm thick cross-linked plate in accordance with to ISO 527-2/5A:2012.

EXPERIMENTAL PART EXAMPLES POLYETHYLENE

[0436] Polyethylenes are all low-density polyethylenes polymerized in a continuous high-pressure tubular reactor.

[0437] Inventive Example 1 (Polymer 1: poly(ethylene-co-1,7-octadiene) polymer with 1.36 vinyl groups/1,000 carbon atoms (C), Density = 922.4 kg/m3, MFR2 = 1.13 g/10 min), i.e. polyethylene of the polymer composition according to the present invention

[0438] Ethylene with recycled CTA was compressed in a 5-stage precompressor and a 2-stage hypercompressor with intermediate cooling to achieve the initial reaction pressure of about 280 MPa (2,800 bar). The total compressor output was around 30,000 kg (30 tons)/hour. In the compressor area, approximately 0.3 kg/hour of propion aldehyde (PA, CAS number: 123-38-6) was added along with approximately 43 kg of propylene/hour as chain transfer agents to maintain an MFR2 of 1 .13 g/10 min. Here 1,7-octadiene was also added to the reactor in an amount of 132 kg/h. The compressed mixture was heated to 155 °C in a preheating section of a front-feed three-zone tubular reactor with an internal diameter of about 40 mm and a total length of 1,200 meters. A mixture of commercially available peroxide radical initiators dissolved in isododecane was injected just after the preheater in an amount sufficient for the exothermic polymerization reaction to reach peak temperatures of about 279 °C, after being cooled to approximately 206 °C. . The subsequent 2nd and 3rd peak reaction temperatures were 272 °C and 245 °C, respectively with a cooling to around 217 °C. The reaction mixture was depressurized by a non-return valve, cooled, and the resulting polymer 1 was separated from the unreacted gas.

[0439] Inventive Example 2 (Polymer 2: poly(ethylene-co-1,7-octadiene) polymer with 0.89 vinyl group/1,000 C, Density = 923.7 kg/m3, MFR2 = 0.92 g/ 10 min), i.e. polyethylene of the polymer composition according to the present invention

[0440] Ethylene with recycled CTA was compressed in a 5-stage precompressor and a 2-stage hypercompressor with intermediate cooling to achieve the initial reaction pressure of about 280 MPa (2,800 bar). The total compressor output was around 30,000 kg (30 tons)/hour. In the compressor area, approximately 3.8 kg/hour of propion aldehyde (PA, CAS number: 123-38-6) was added as chain transfer agents to maintain an MFR2 of 0.92 g/10 min. Here 1,7-octadiene was also added to the reactor in an amount of 89 kg/h. The compressed mixture was heated to 162 °C in a preheating section of a front-feed three-zone tubular reactor with an internal diameter of about 40 mm and a total length of 1,200 meters. A mixture of commercially available peroxide radical initiators dissolved in isododecane was injected just after the preheater in an amount sufficient for the exothermic polymerization reaction to reach peak temperatures of about 286 °C, after being cooled to approximately 231 °C. . The subsequent 2nd and 3rd peak reaction temperatures were 274 °C and 248 °C, respectively with a cooling around 222 °C. The reaction mixture was depressurized by a non-return valve, cooled and the resulting polymer 2 was separated from the unreacted gas.

[0441] Inventive Example 3 (Polymer 3: poly(ethylene-co-1,7-octadiene) polymer with 1.34 vinyl groups/1,000 C, Density = 924.9 kg/m3, MFR2 = 1.46 g/ 10 min), i.e. polyethylene of the polymer composition according to the present invention

[0442] Ethylene with recycled CTA was compressed in a 5-stage precompressor and a 2-stage hypercompressor with intermediate cooling to achieve the initial reaction pressure of about 280 MPa (2,800 bar). The total compressor output was around 30,000 kg (30 tons)/hour. In the compressor area, approximately 3.9 kg/hour of propion aldehyde (PA, CAS number: 123-38-6) was added as chain transfer agents to maintain an MFR2 of 1.46 g/10 min. Here 1,7-octadiene was also added to the reactor in an amount of 148 kg/h. The compressed mixture was heated to 159 °C in a preheating section of a front-feed three-zone tubular reactor with an internal diameter of about 40 mm and a total length of 1,200 meters. A mixture of commercially available peroxide radical initiators dissolved in isododecane was injected just after the preheater in an amount sufficient for the exothermic polymerization reaction to reach peak temperatures of about 273 °C, after being cooled to approximately 207 °C. The subsequent 2nd and 3rd peak reaction temperatures were 257 °C and 226 °C, respectively with a cooling to around 209 °C. The reaction mixture was depressurized by a non-return valve, cooled and the resulting polymer 3 was separated from the unreacted gas.

[0443] Inventive Example 4 (Polymer 4: poly(ethylene-co-1,7-octadiene) polymer with 0.94 vinyl group/1,000 C, Density = 922.3 kg/m3, MFR2 = 1.91 g/ 10 min), i.e. polyethylene of the polymer composition according to the present invention

[0444] Ethylene with recycled CTA was compressed in a 5-stage precompressor and a 2-stage hypercompressor with intermediate cooling to achieve the initial reaction pressure of about 290 MPa (2,900 bar). The total compressor output was around 30,000 kg (30 tons)/hour. In the compressor area, approximately 0.4 kg/hour of propion aldehyde (PA, CAS number: 123-38-6) was added along with approximately 117 kg of propylene/hour as chain transfer agents to maintain an MFR2 of 1 .91 g/10 min. Here 1,7-octadiene was also added to the reactor in an amount of 77 kg/h. The compressed mixture was heated to 162 °C in a preheating section of a front-feed three-zone tubular reactor with an internal diameter of about 40 mm and a total length of 1,200 meters. A mixture of commercially available peroxide radical initiators dissolved in isododecane was injected just after the preheater in an amount sufficient for the exothermic polymerization reaction to reach maximum temperatures of about 267 °C, after being cooled to approximately 205 °C. The 2nd and 3rd subsequent maximum reaction temperatures were 260 °C and 237 °C, respectively with a cooling around 213 °C. The reaction mixture was depressurized by a non-return valve, cooled and the resulting polymer 4 was separated from the unreacted gas.

[0445] Comparative Example 1 (Polymer 5: poly(ethylene-co-1,7-octadiene) polymer with 0.82 vinyl group/1,000 C, Density = not measured kg/m3, MFR2 = 2.1 g/10min ), i.e. polyethylene of comparative polymer composition

[0446] The purified ethylene was liquefied by compression and cooling at a pressure of 9 MPa (90 bar) and a temperature of -30 °C and divided into two equal streams of approximately 14,000 kg (14 tons)/hour each. CTA (methyl ethyl ketone (MEK)), air, and a commercial peroxide radical initiator dissolved in a solvent were added to the two liquid ethylene streams in individual amounts. 1,7-octadiene was added as a comonomer to the reactor in an amount of 190 kg/h. The two mixtures were pumped separately through an array of 4 intensifiers to reach pressures of 220 (2,200) to 230 MPa (2,300 bar) and outlet temperatures of about 40 °C. These two streams were fed respectively into the front (zone 1) (50%) and the side (zone 2) (50%) of a tubular reactor with two divided feed zones. The internal diameters and lengths of the two reactor zones were 32 mm and 200 m for zone 1 and 38 mm and 400 m for zone 2. MEK was added in amounts of 115 kg/h to the head stream to maintain a MFR2 of about 2.1 g/10 min. The front feed stream was passed through a heating section to reach a temperature sufficient to initiate the exothermic polymerization reaction. The reaction reached maximum temperatures of 253 °C and 290 °C in the first and second zones, respectively. The side feed stream cooled the reaction to a second zone initiation temperature of 165 °C. The peroxide and air solution was added to both streams in sufficient quantities to reach the maximum desired temperatures. The reaction mixture was depressurized by the product valve, cooled, and the polymer was separated from the unreacted gas. The polymer obtained had vinyl groups in the amount of 0.82/1,000 C and MFR2 = 2.1 g/10 min.

[0447] Comparative Example 2 - (Polymer 6: poly(ethylene-co-1,7-octadiene) polymer with 0.86 vinyl group/1,000 C, Density = not measured kg/m3, MFR2 = 3.1 g/ 10 min), i.e. polyethylene of comparative polymer composition

[0448] Ethylene with recycled CTA was compressed in a 5-stage precompressor and a 2-stage hypercompressor with intermediate cooling to achieve the initial reaction pressure of about 300 MPa (3,000 bar). The total compressor output was around 30,000 kg (30 tons)/hour. In the compressor area, approximately 121 kg of propylene/hour were added as chain transfer agents to maintain an MFR2 of 3.1 g/10 min. Here 1,7-octadiene was also added to the reactor in an amount of 57 kg/h. The compressed mixture was heated to 165 °C in a preheating section of a front-feed three-zone tubular reactor with an internal diameter of about 40 mm and a total length of 1,200 meters. A mixture of commercially available peroxide radical initiators dissolved in isododecane was injected just after the preheater in an amount sufficient for the exothermic polymerization reaction to reach maximum temperatures of about 283 °C, after being cooled to approximately 225 °C. The 2nd and 3rd subsequent maximum reaction temperatures were 283 °C and 267 °C, respectively with a cooling around 235 °C. The reaction mixture was depressurized by a non-return valve, cooled, and the polymer was separated from the unreacted gas.

[0449] Comparative Example 3 (Polymer 7: poly(ethylene-co-1,7-octadiene) polymer with 0.77 vinyl group/1,000 C, Density = 922.1 kg/m3, MFR2 = 1.82 g/ 10 min), i.e. polyethylene of comparative polymer composition

[0450] Ethylene with recycled CTA was compressed in a 5-stage precompressor and a 2-stage hypercompressor with intermediate cooling to achieve the initial reaction pressure of about 290 MPa (2,900 bar). The total compressor output was around 30,000 kg (30 tons)/hour. In the compressor area, approximately 0.8 kg/hour of propion aldehyde (PA, CAS number: 123-38-6) was added along with approximately 123 kg of propylene/hour as chain transfer agents to maintain an MFR2 of 1 .82 g/10 min. Here 1,7-octadiene was also added to the reactor in an amount of 55 kg/h. The compressed mixture was heated to 163 °C in a preheating section of a front-feed three-zone tubular reactor with an internal diameter of about 40 mm and a total length of 1,200 meters. A mixture of commercially available peroxide radical initiators dissolved in isododecane was injected just after the preheater in an amount sufficient for the exothermic polymerization reaction to reach maximum temperatures of about 274 °C, after being cooled to approximately 204 °C. The 2nd and 3rd subsequent maximum reaction temperatures were 261 °C and 244 °C, respectively with a cooling around 216 °C. The reaction mixture was depressurized by a non-return valve, cooled, and the polymer was separated from the unreacted gas.

[0451] Comparative Example 4 (Polymer 8: poly(ethylene-co-1,7-octadiene) polymer with 0.58 vinyl group/1,000 C, Density = 922.1 kg/m3, MFR2 = 1.75 g/ 10 min), i.e. polyethylene of comparative polymer composition

[0452] Ethylene with recycled CTA was compressed in a 5-stage precompressor and a 2-stage hypercompressor with intermediate cooling to achieve the initial reaction pressure of about 290 MPa (2,900 bar). The total compressor output was around 30,000 kg (30 tons)/hour. In the compressor area, approximately 1.6 kg/hour of propion aldehyde (PA, CAS number: 123-38-6) was added along with approximately 123 kg of propylene/hour as chain transfer agents to maintain an MFR2 of 1 .75 g/10 min. Here 1,7-octadiene was also added to the reactor in an amount of 34 kg/h. The compressed mixture was heated to 164 °C in a preheating section of a front-feed three-zone tubular reactor with an internal diameter of about 40 mm and a total length of 1,200 meters. A mixture of commercially available peroxide radical initiators dissolved in isododecane was injected just after the preheater in an amount sufficient for the exothermic polymerization reaction to reach maximum temperatures of about 276 °C, after being cooled to approximately 200 °C. The 2nd and 3rd subsequent maximum reaction temperatures were 266 °C and 251 °C, respectively with a cooling around 219 °C. The reaction mixture was depressurized by a non-return valve, cooled, and the polymer was separated from the unreacted gas.

[0453] Comparative Example 5 (Polymer 9: poly(ethylene-co-1,7-octadiene) polymer with 0.71 vinyl group/1,000 C, Density = 922.3 kg/m3, MFR2 = 0.68 g/ 10 min), i.e. polyethylene of comparative polymer composition

[0454] Ethylene with recycled CTA was compressed in a 5-stage precompressor and a 2-stage hypercompressor with intermediate cooling to achieve the initial reaction pressure of about 290 MPa (2,900 bar). The total compressor output was around 30,000 kg (30 tons)/hour. In the compressor area, approximately 1.2 kg/hour of propion aldehyde (PA, CAS number: 123-38-6) was added along with approximately 87 kg of propylene/hour as chain transfer agents to maintain an MFR2 of 0 .68 g/10 min. Here 1,7-octadiene was also added to the reactor in an amount of 56 kg/h. The compressed mixture was heated to 164 °C in a preheating section of a front-feed three-zone tubular reactor with an internal diameter of about 40 mm and a total length of 1,200 meters. A mixture of commercially available peroxide radical initiators dissolved in isododecane was injected just after the preheater in an amount sufficient for the exothermic polymerization reaction to reach maximum temperatures of about 277 °C, after being cooled to approximately 206 °C. The 2nd and 3rd subsequent maximum reaction temperatures were 270 °C and 249 °C, respectively with a cooling around 217 °C. The reaction mixture was depressurized by a non-return valve, cooled, and the polymer was separated from the unreacted gas.

POLYMER COMPOSITION

[0455] Formulations, that is, the polymer composition of the present invention, with the use of polyethylene, as described herein, cross-linking agent and no antioxidant, and also comparative examples, were prepared on a laboratory scale and compared, see Table 1. The cross-linking agent was added to the polyethylene by distributing the cross-linking agent (the cross-linking agent is in a liquid form) at 70°C to the polyethylene pellets. The wet pellets were kept at 80 °C until the pellets were dry. The amount of cross-linking agent, e.g. peroxide, e.g. DCP, was selected for each base resin so that about the same degree of cross-linking as measured by the Hot Determination method (with a load of 20N/ cm2) has been achieved.

[0456] For hot and methane measurements, 1.5 mm thick plates were compression molded and crosslinked at 180 °C as described in the determination method in 'preparation of crosslinked plates, i.e. method for crosslinking plates '. Methane was measured directly after cross-linking in 2 samples as described in the determination method under the 'GC (plate) analysis protocol, i.e. method for GC analysis' and the reported value is an average of the 2 measurements. The hot setting was measured on 3 samples at 200 °C with a load of 20 N/cm2, as described in the determination method in “Hot method for the sample from a grid plate”. TABLE 1.

[0457] The examples surprisingly show that the polymer composition of the present invention, obtained from polyethylene, achieves excellent levels of crosslinking (< 100% hot elongation) while forming < 200 ppm of methane. All comparative examples form more than 200 ppm methane when cross-linked to a technically equivalent level. Thus, the polymer compositions of the present invention, wherein the polymer composition contains a total amount of vinyl groups consisting of B vinyl groups per 1,000 carbon atoms and comprises a crosslinking agent in an amount that is Z% by weight, are especially suitable for end applications where a system is required that combines a highly cross-linked system with the simultaneous formation of small volatile decomposition products, typically methane. Consequently, a highly cross-linked system is surprisingly achieved even when a comparatively small amount of cross-linking agent, e.g. peroxide, e.g. DCP, is used in accordance with the present invention in the polymer composition containing a total amount of vinyl groups consisting of B vinyl groups per 1,000 carbon atoms. Thus, with comparatively low amount of DCP, i.e. the cross-linking agent in an amount of Z < Z2, where Z2 is 0.60, the surprisingly good levels of cross-linking used measured hot (< 100% hot elongation ) are achieved by the polymer compositions of the present invention. In contrast, comparative polymer compositions, which contain a smaller total amount of vinyl groups, require more than 0.6% by weight of the cross-linking agent, here DCP, to achieve sufficient cross-linking levels, leading to the formation of more volatile decomposition, typically methane.

Claims (24)

1. A polymer composition comprising a polyethylene and a cross-linking agent, characterized in that the polymer composition contains a total amount of vinyl groups consisting of B vinyl groups per 1,000 carbon atoms, and Bi < B, wherein Bi is 0.88 when measured before cross-linking according to the ASTM D6248-98 method; and wherein the cross-linking agent is present in an amount that is Z% by weight, based on the total amount (100% by weight) of the polymer composition, and Z < Z2, where Z2 is 0.60. 2. Polymer composition according to claim 1, characterized by the fact that the polyethylene is unsaturated or saturated. 3. Polymer composition according to any one of the preceding claims, characterized by the fact that decomposition of the crosslinking agent, during crosslinking of the polymer composition, results in the formation of less than 200 ppm of methane, when measured according to with the method for GC Analysis. 4. Polymer composition according to any one of the preceding claims, wherein the polymer composition is characterized by the fact that it is cross-linked and has a heat elongation, with a load of 20 N/cm2, which is less than 175 %, when measured according to the method for Hot Setting Determination. 5. Polymer composition according to any one of the preceding claims, characterized by the fact that polyethylene is an unsaturated LDPE polymer. 6. Polymer composition according to any one of the preceding claims, characterized by the fact that polyethylene is a copolymer of a monomer with at least one polyunsaturated comonomer and with zero, one or more other comonomers and in which said The total amount of vinyl groups (B) present in the polymer composition includes vinyl groups originating from said at least one polyunsaturated comonomer, for example, diene. 7. Polymer composition according to any one of the preceding claims, characterized by the fact that polyethylene is a copolymer of a monomer with at least one polyunsaturated comonomer, wherein the polyunsaturated comonomer is a straight carbon chain with at least 8 carbon atoms and at least 4 carbon atoms between the unconjugated double bonds, of which at least one is terminal, for example, from C8 to C14 unconjugated diene, for example, selected from 1.7 -octadiene, 1,9-decadiene, 1,11-dodecadiene, 1,13-tetradecadiene or mixtures thereof. 8. Polymer composition according to any one of the preceding claims, characterized by the fact that polyethylene is a copolymer of ethylene and 1,7-octadiene. 9. Polymer composition according to any one of the preceding claims, characterized in that the polyethylene is a homopolymer or copolymer of low density polyethylene (LDPE), for example, an ethylene LDPE copolymer with one or more comonomers polyunsaturated and with zero, one or more other comonomers. 10. The polymer composition of any one of the preceding claims, wherein the polymer composition is characterized by the fact that it has, prior to cross-linking, a loading melt flow rate of 2.16 kg (MFR2) and at 190 °C, determined according to the ISO 1133-1:2011 method, where MFR2 is A g/10 min and A < A2, where A2 is 2.5 or 2 or 1.7. 11. Polymer composition according to any one of the preceding claims, characterized by the fact that said polyethylene, before cross-linking: has a complex viscosity (n*) at 0.05 rad/s, which is X Pas, and X1 < X < X2, where X1 is 7,600 and 380, both complex viscosities (n*) are determined according to the ISO 6721-1 method on stabilized polyethylene samples. 12. Polymer composition according to any one of the preceding claims, characterized by the fact that B1 is 0.90, 0.95, 1.00, 1.05, 1.10, 1.15, 1.20, 1.25 or 1.30, and/or Z2 is 0.48 or 0.46. 13. Polymer composition according to any of the preceding claims, characterized by the fact that B ≤ B2 and B2 is 3.0 and Z1 ≤ Z ≤ Z2, where Z1 is 0.01. 14. Polymer composition according to any one of the preceding claims, characterized by the fact that the polyethylene contains a total amount of vinyl groups consisting of P vinyl groups per 1,000 carbon atoms, where P1 < P < P2 and, P1 is 0.89 and P2 is 3.0, preferably where P1 is 0.90 and P2 is 1.5. 15. Polymer composition according to any one of the preceding claims, wherein the polymer composition is characterized by the fact that it simultaneously satisfies the following: P1 ≤ P≤ P2 wherein P1 is 0.89 and P2 is 3.0 ; Z1 ≤ Z ≤ Z2 where Z1 is 0.15 and Z2 is 0.60; and A1 ≤ A ≤ A2 where A1 is 0.15 and A2 is 3.0. 16. Polymer composition according to any one of the preceding claims, wherein the polymer composition is characterized by the fact that it simultaneously satisfies the following: Pi < P < P2 wherein Pi is 0.9 and P2 is 1.5 ;Z1 ≤ Z ≤ Z2 where Z1 is 0.25 and Z2 is 0.50; and A1 ≤ A ≤ A2 where A1 is 0.60 and A2 is 2.5. 17. Polymer composition according to any one of the preceding claims, characterized in that the crosslinking agent comprises peroxide. 18. Article characterized by the fact that it is obtained from a process comprising the use of a polymer composition, according to any one of claims 1 to 17, wherein the article is, for example, a cable. 19. Article according to claim 18, wherein the article is characterized by the fact that it comprises layer (or layers), for example, insulating layer (or layers), which is obtained from a polymer composition, according to any one of claims 1 to 17, wherein the article is, for example, a cable. 20. Article according to claim 18 or 19, characterized by the fact that it is a power cable. 21. Process for producing a polymer composition according to any one of claims 1 to 17, wherein the process is characterized by the fact that it comprises mixing polyethylene with the crosslinking agent. 22. Process for producing an article according to any one of claims 18 to 20, wherein the process is characterized by the fact that it comprises the use of a polymer composition according to any one of claims 1 to 17. 23. Process according to claim 22, characterized by the fact that said article is a power cable and wherein said process comprises the steps of: by) melt mixing a polymer composition, as defined in any one of claims 1 to 17, optionally together with additional components; a) applying the melt mixture obtained in step a0) to a conductor to form at least one layer. 24. Process according to claim 23, characterized by the fact that said article is a cross-linked power cable and wherein said process further comprises the step of: b) cross-linking the at least one layer of cable obtained in the step The).