EA045796B1 - POLYETHYLENE WITH HIGH VINYL CONTENT AND VALUABLE RHEOLOGICAL PROPERTIES - Google Patents

Description

Technical field

The present invention relates to a polyethylene, polymer composition, product, for example, containing layer(s), for example, insulating layer(s), which is obtained from the specified polyethylene or specified polymer composition, and the specified product may be a cable, for example, power cable, to a method for producing a product, which includes the use of a polymer composition, and to methods for producing polyethylene and a polymer composition. Polyethylene and polymer compositions containing it can be used in various end applications such as cable and conductor (W&C) manufacturing, especially for cables such as power cables, for example in medium voltage (MV) cables and, for example, in high voltage cables (HV), and, for example, in extra high voltage (EHV) cables. In addition, polyethylene and polymer compositions containing it can be used in both the alternating current (AC) and direct current (DC) regions.

State of the art

Polyethylenes produced by the high pressure (HP) process are widely used in demanding applications in which the polymers must meet high mechanical and/or electrical requirements. For example, in the field of W&C, for example in the field of power cables, for example in the field of LV, MV, HV and EHV, where the mechanical and electrical properties of polyethylene and polymer compositions containing polyethylene are of particular importance.

For example, in the field of power cables, in particular in the field of MV and especially HV and EHV cables, the electrical properties of the polymer composition are of significant importance. In addition, the electrical properties that are important may differ between cable applications, as is the case with differences between AC and DC cable applications.

In addition, it is also known that cross-linking polymers, such as polyethylenes, significantly improves the thermal and deformation resistance, mechanical strength, chemical resistance and abrasion resistance of the polymer. Therefore, cross-linked polymers are widely used in various end-use applications, such as the aforementioned application in the cable and wire (W&C) industry.

Moreover, in the cable industry, an electrical conductor is usually coated first with an inner semiconducting layer, then with an insulating layer and an outer semiconducting layer. To these layers may be added additional layer(s), such as screen(s) and/or auxiliary barrier layer(s), for example, one or more moisture barrier layers and one or more shell layers.

Due to the advantages mentioned herein that can be achieved by crosslinking, insulating layer and semiconductive layers for cables are typically produced using crosslinkable polymer compositions. Then the polymer compositions are cross-linked in the formed layered cable structure.

In addition, such crosslinkable polymer compositions containing low-density polyethylene (LDPE) are among the predominant cable insulation materials for power cables today.

Cross-linking can be accomplished using cross-linking agents, wherein the cross-linking agents degrade to form free radicals. Such cross-linking agents, such as peroxides, are typically added to the polymer material before or during cable extrusion. Said crosslinking agent should preferably remain stable during the extrusion stage. The extrusion step should preferably be carried out at a temperature low enough to minimize early degradation of the crosslinker, but high enough to ensure proper melting and homogenization of the polymer composition. If a significant amount of crosslinking agent, such as peroxide, is already decomposed in the extruder, resulting in premature crosslinking being initiated, so-called scorching may occur, i.e. heterogeneity, unevenness of the surface and possible change in color of the different layers of the finished cable. Thus, any significant degradation of the cross-linking agents must be avoided, e.g. free radical generating agents during the extrusion process. In contrast, crosslinkers should ideally only degrade during the subsequent crosslinking step at elevated temperature.

Elevated temperature increases the rate of decomposition of crosslinking agents and therefore increases the rate of crosslinking, and the required one, i.e. a given degree of cross-linking can be achieved more quickly.

In addition, when cross-linking a polymer composition, for example in a cable, the decomposition of cross-linking agents, for example, peroxides, during the cross-linking process also leads to additional formation of peroxide decomposition products. Some peroxide decomposition products are volatile and their main component is methane when peroxides are of the types typically used for crosslinking, for example, cables. The peroxide decomposition products remain largely entrapped in the polymer composition, such as cable, after cross-linking. This causes, for example, problems in terms of the cable production process and also in terms of the quality of the finished cable.

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Especially MV, HV and EHV power cables must have high quality layers to ensure safety during the installation process and the final use of these cables. For example, during installation it is important to avoid igniting said trapped decomposition products, such as flammable methane, for example when removing end caps. During operation, volatile peroxide decomposition products formed in the cable at the cross-linking stage can create gas pressure and, therefore, cause defects in the screen and at the joints. For example, if a cable core is equipped with a metal barrier, gaseous products may exert pressure, especially at joints and ends, causing the system to fail. Thus, it is necessary to reduce the content of such volatile peroxide decomposition products to a sufficiently low level before proceeding with subsequent cable production steps.

A sufficiently low level of volatile peroxide decomposition products ensures the safety of using a polymer composition containing LDPE during installation, for example, when installing a cable, as well as with auxiliary elements, such as a cable set. Thus, at present, in the production of cables, a so-called degassing stage is required, which ensures a reduction in the content of volatile peroxide decomposition products. The degassing step is time and energy intensive and therefore an expensive step in the cable manufacturing process. Degassing requires large heating chambers, which must be well ventilated to prevent the accumulation of, for example, flammable methane. Cable core, i.e. layers and conductor, usually wound on cable drums, are normally maintained at this degassing stage at an elevated temperature in the range of 50-80°C, for example 60-70°C, for extended periods of time. When exposed to the required temperatures, thermal expansion and softening of the insulation may occur, which leads to unwanted deformation of the formed cable layers, directly leading to cable failure. Therefore, degassing of HV and EHV cables with a large cable mass often needs to be carried out at a reduced temperature, which further increases the degassing time. Accordingly, there is a need to find new solutions to overcome the problems existing in the prior art.

In addition, cross-linking the polymer composition contained, for example, in a cable, significantly improves the thermal and strain resistance, mechanical strength, chemical resistance and abrasion resistance of the polymer composition and the cable containing the polymer composition.

In this context, one may consider US5539075, which relates to a process for producing an unsaturated copolymer of ethylene and at least one monomer, where the monomer is a polyunsaturated compound and can be copolymerized with ethylene.

Publication EP2318210B1 relates to a polymer composition comprising an unsaturated LDPE copolymer of ethylene with one or more polyunsaturated comonomers and is suitable for crosslinked polymer applications. The specified polymer composition has a melt flow rate under a load of 2.16 kg, MFR2, of at least 2.8 g/10 min. and contains carbon-carbon double bonds in an amount of at least 0.40 carbon-carbon double bonds/1000 carbon atoms.

In addition, different cables, cable structures and lines may require different materials, e.g. polyethylenes and polymer compositions containing polyethylenes. In addition, it is not possible to use all cables or cable structures on all cable lines using so-called cross-linked (in this case more properly cross-linked) polyethylene (XLPE) materials of standard viscosity, having a melt flow index at a load of 2.16 kg, MTR ₂ . about 2 g/10 min. This is because the standard viscosity XLPE materials listed do not have sufficient sag resistance. Insufficient sag resistance is usually corrected, in the case of cables, with the help of materials having MTR ₂ values of less than 2 g/10 min. Materials that have MFR2 values less than 2 g/10 min have high viscosity and increased resistance to sagging. Improved sag resistance is required for large cable structures and for cable production on catenary cable lines, as well as for production on horizontal cable lines. For example, horizontal continuous vulcanization lines, such as the Mitsubishi Dainichi Continuous Vulcanization (MDCV) line, as well as chain continuous vulcanization (CCV) lines (especially for thicker structures) for the production of cables usually require the use of polymeric materials, e.g. layers that have a lower MFI ₂ value compared to the MFI ₂ polymer materials (for example, standard viscosity XLPE materials) used on vertical continuous vulcanization (VCV) lines and on CCV lines (for thinner structures).

In horizontal continuous vulcanization lines for cable production, the conductor may be immersed in a layer of insulation, and if polymer materials are used that have too high a MFR2 value, then the immersion of the conductor may also result in eccentricity of the conductor in the cable core and/or eccentricity of the cable core.

Similar to CCV lines, if polymer materials are used that have too high a MFR2 value, i.e. also have too low sag resistance, the wall thickness may become too thick as the soft molten polymer material of the insulating layer can flow off the conductor. This leads to a downward displacement of the insulating layer and causes eccentricity, for example, the so-called pear-shaped shape of the cable core.

In addition, the lack of sag resistance can be dealt with in various ways, such as the use of eccentric tools in the extrusion head to compensate for the effect of conductor immersion;

twisting the cable core to counteract the displacement of the conductor;

the use of double rotation technology to counteract the formation of pear shape, as well as the use of the so-called inlet heat treatment (IHT).

Accordingly, to counteract this sag, polymeric materials having a relatively lower MFI2 value and a higher viscosity are typically used, as has already been described.

However, materials having high viscosity produce higher melt temperatures under normal extrusion conditions, which may lead to an increased risk of premature crosslinking and hence the formation of prematurely crosslinked material, i.e. soot. Carbon deposits, as already described, may represent inhomogeneity, surface roughness and/or possible discoloration in different layers of, for example, a finished cable. Carbon deposits can significantly reduce cable line productivity because it significantly limits how long production can take before cleaning is necessary and therefore reduces production speed. Thus, when producing cables using polymer materials having a lower MFR2 value, which cause a higher melt temperature, a reduced production speed is necessary to reduce the melt temperature and, therefore, minimize scorching.

Accordingly, the disadvantage of reducing the MFR ₂ value of a material may also be the need to change technological conditions, for example, reducing the production speed.

Process conditions, in addition to sag resistance, are also properties that are important for crosslinkable XLPE materials, such as peroxide crosslinkable XLPE materials. Ideally, the material should have a low viscosity at the extrusion stage of the process in order to have the required low melt temperature at the extrusion stage. On the other hand, a relatively higher material viscosity may be required during the crosslinking step of the process. If the XLPE crosslinkable material provides a low melt temperature, there is less risk of fouling during extrusion of, for example, a cable structure, compared to extrusion using another XLPE crosslinkable material that provides a higher melt temperature.

Sag resistance and viscosity under processing conditions can be visualized using viscosity curves obtained from rheology measurements with plane-parallel geometry. This sag resistance is then visualized using complex viscosity (η*) at very low shear rates, i.e. η*ο and η* _0.05 at 0 rad/s and 0.05 rad/s, respectively, and then the indicated viscosity under processing _conditions is visualized using the complex viscosity η* ₃₀₀ at 300 rad/s.

The next important property of XLPE is the degree of cross-linking, and the required degree of cross-linking should be achieved, optimally, with the smallest possible amount of cross-linking agent, such as peroxide. The degree of crosslinking can be measured using a so-called thermal strain test. According to the specified thermal strain test, the lower the thermal strain elongation value, the more cross-linked the material is. The minimum possible amount of crosslinking agent ensures a reduction in the content of volatile peroxide decomposition products, as well as a reduction in the time required for degassing.

The extrusion and cross-linking steps involved in, for example, a cable manufacturing process may have different requirements. A critical parameter for the extrusion stage, as already described, is that the polymer material provides a low melt temperature to reduce the risk of scorching. This is determined by the rheological properties in the shear rate region that the polymer material has in the extruder, for example due to the low complex viscosity (η*) at 300 rad/s. Low complex viscosity (η*) at 300 rad/s is usually associated with a polymer material having a higher melt flow index (MFR ₂ ).

However, the increase in melt flow often must be balanced because a polymer material with a high MFI ₂ value also has low sag resistance, which can result in, for example, an off-center cable, which is unacceptable. The rheological property that influences sag resistance is complex viscosity (η*) at a very low shear rate such as 0 rad/s. However, the complex viscosity (η*) at 0 rad/s is an extrapolated value and therefore the measured complex viscosity (η*) at 0.05 rad/s is used instead in this context.

Accordingly, there is a need to find new solutions to overcome the problems existing in the prior art.

Description of the invention

The present invention relates to polyethylene, wherein said polyethylene contains a total number of vinyl groups, which is the value B of vinyl groups per 1000 carbon atoms, and B1 < B < B2, where B1 is 0.45 and B2 is 2.0, measured in accordance with ASTM D6248-98 method; and has a complex viscosity (η*) at 0.05 rad/s, which is the value of X, Pa-s, and X ₁ < X < X ₂ , where X ₁ is 12000 and X ₂ is 24000; and complex viscosity (η*) at 300 rad/s, which is the value of Y, Pa-s, and Y1 < Y < Y2, where Y ₁ is 250 and Y2 is 350, both complex viscosities (η*) being determined according to with ISO 6721-1 method on stabilized polyethylene samples; and has a melt flow rate at a load of 2.16 kg (MFR2), where the specified MFR2 is the value of A, g/10 min, and A ₁ < A <A2; where A ₁ is 0.50 and A ₂ is 1.70, when measured according to the ISO 1133-1:2011 method.

Details of the ASTM D6248-98 method are provided in the Measurement Methods section of this document.

Details of the ISO 6721-1 method regarding Rheology, dynamic method (viscosity determination) ISO 6721-1 are provided in this document under Measurement methods.

The complex viscosity (η*) at 0.05 rad/s, which represents the X value, Pa-s, in this context visualizes the sag resistance, and the complex viscosity (η*) at 300 rad/s, which represents the Y value , Pa-s, in this context visualizes viscosity under processing conditions.

The polyethylene described herein contains vinyl groups, for example, allyl groups. Vinyl groups are functional groups that contain double carbon bonds. In addition, polyethylene may additionally contain other functional groups also containing carbon-carbon double bonds. Other functional groups also containing carbon-carbon double bonds may be, for example, vinylidene groups and/or vinylene groups. Vinylene groups have either a cis or trans configuration.

The polyethylene according to the present invention, as defined in this context, unexpectedly combines in one polymer, i.e. The polyethylene of the present invention has good processability, for example, high flowability, which is usually associated only with polymers having a relatively high MFR ₂ value, with excellent sag resistance, which is usually associated only with polymers having a relatively low MFR ₂ value.

Moreover, the fact that said polymer, i.e. The proposed polyethylene, combines excellent sag properties with good processability, such as flow, is also illustrated by the fact that this polyethylene exhibits a balanced complex viscosity (η*) at 300 rad/s and at 0.05 rad/s, both complex viscosities ( η*) is determined in accordance with the ISO 6721-1 method on stabilized polyethylene samples. The complex viscosity (η*) at 300 rad/s is correspondingly low and the complex viscosity (η*) at 0.05 rad/s is correspondingly high, resulting in the polymer, i.e. The proposed polyethylene has improved technological properties in the extruder, and at the same time provides the ability to produce cables, including large cable structures, with good alignment during cable production on all types of cable lines. In this way, the said cables can accordingly be produced containing layers, for example insulating layers, made from the polyethylene according to the invention.

Moreover, in addition to the unexpected combination of excellent sag properties with good processability, the polyethylene of the present invention can also unexpectedly maintain the technically required degree of cross-linking when using cross-linking agents, for example, peroxides, which are known in the art, i.e. provide a technically more suitable degree of cross-linking compared to polyethylenes containing a lower total number of vinyl groups.

Thus, the polyethylene according to the present invention obviously has a great advantage for use, for example, in the production of stitched and cross-linked products, for example cables, for example cable layers, for example cable insulation layers.

The proposed polyethylene is usually used to obtain a polymer composition. Said polymer composition obtained using the polyethylene according to the invention may be crosslinkable and, therefore, may be highly suitable for producing crosslinkable articles, for example, one or more crosslinkable cable layers, for example, one or more crosslinkable cable insulating layers, and said layers hereinafter subjected to stitching.

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Crosslinkable is a well-known expression and means that the polymer composition can be crosslinked, for example, through the formation of radicals, with the formation of bridges, including between polymer chains.

The polyethylene of the present invention, which has a comparatively lower MFR2, A value, surprisingly exhibits an increased degree of cross-linking compared to polyethylenes having a comparatively higher _MFR2 value.

Said total number of vinyl groups, which is the B value of vinyl groups per 1000 carbon atoms, means the total number of vinyl groups, which is the B value of vinyl groups per 1000 carbon atoms present in the polyethylene according to the present invention, when measured before any cross-linking.

The ASTM D6248-98 method for determining the number of vinyl groups is described in the Measurement Methods section.

PTR ₂ is determined in accordance with ISO 1133-1:2011 under a load of 2.16 kg. The measurement temperature is chosen, as is known, depending on the type of polymer used.

As used herein, exemplary subsets of the described properties, additional features, such as additional properties or ranges thereof, and exemplary embodiments generally refer to said polyethylene as well as a polymer composition derived from said polyethylene, or containing said polyethylene, to the end applications and to any processes associated therewith, and they can be combined in any combination.

It should be noted that the expressions embodiment or embodiments, even when specifically indicated in this context, always refer to an embodiment or embodiments of the present invention.

In embodiments of the present invention, the polyethylene described herein contains B vinyl groups per 1000 carbon atoms as described herein, with B < B ₂ and B 2 equal to 3.0.

In a further embodiment, the present invention provides polyethylene as described herein, wherein B1 is equal to 0.35, 0.40 or 0.45.

In an additional embodiment, a polyethylene is described in which B1 is equal to 0.45.

An additional embodiment of the present invention is provided in which the polyethylene has a melt flow index under load of 2.16 kg (MFR ₂ ), measured in accordance with the ISO 1133-1:2011 method, and the specified MFR ₂ has a value of A g/10 min, and A1 < A < A ₂ ; where A ₁ is 0.05 and A ₂ is 1.70, and contains the total number of vinyl groups determined in accordance with the ASTM D6248-98 method, which has a value of B vinyl groups per 1000 carbon atoms, and B1 222 B, where B1 equals 0.45.

In an additional embodiment, a polyethylene is described in which B1 is equal to 0.50.

In a further embodiment of the present invention, a polyethylene is described in which B1 is equal to 0.52.

In an additional embodiment, a polyethylene is described in which B1 is equal to 0.54. In an additional embodiment, a polyethylene is described in which B1 is equal to 0.55.

In a further embodiment, a polyethylene is described in which B1 is 0.55 and/or B < B ₂ and B ₂ is 3.0.

In an additional embodiment, a polyethylene is described in which B1 is equal to 0.60.

Additional embodiments disclose polyethylene in which B1 is 0.55, 0.60, 0.65, or 0.70.

Additional embodiments disclose polyethylene in which B1 is 0.53, 0.61, 0.66, 0.71, 0.75, 0.80, 0.82, or 0.84.

Additional embodiments disclose polyethylene in which B1 is 0.75, 0.80, 0.82, or 0.84.

In an additional embodiment, a polyethylene is described in which B1 is equal to 0.82. In an additional embodiment, a polyethylene is described in which B1 is equal to 0.84. In an additional embodiment, a polyethylene is described in which B1 is equal to 0.86.

In a further embodiment, the proposed polyethylene contains a total number of vinyl groups (B), with B1 equal to 0.88.

The number of vinyl groups in this embodiment means the total number of vinyl groups present in the polyethylene. The term vinyl group in this context has its usual meaning, i.e. fragment -CH= _CH2 . In addition, polyethylene may additionally contain other functional groups also containing carbon-carbon double bonds. Other functional groups also containing carbon-carbon double bonds may be, for example, vinylidene groups and/or vinylene groups. Vinylene groups have either a cis or trans configuration. For the avoidance of doubt, vinylidene groups and vinylene groups are not

- 5 045796 are vinyl groups in accordance with the terms used in this context. Polyethylene in this context means both a homopolymer in which the unsaturation is provided by a chain transfer agent and a copolymer in which the unsaturation is provided by polymerization of a monomer together with at least a polyunsaturated comonomer, optionally in the presence of a chain transfer agent, and also optionally in combination with additional comonomers.

In one embodiment, the polyethylene is an unsaturated copolymer, which, as already mentioned in this context, contains one or more polyunsaturated comonomers.

In addition, the source of said vinyl groups (B) present in the unsaturated copolymer may be said polyunsaturated comonomer, the polyethylene production process, and optionally any chain transfer agent used.

If the polyethylene in the polymer composition is an unsaturated copolymer containing at least one polyunsaturated comonomer, then the polyunsaturated comonomer is an unbranched carbon chain containing at least 8 carbon atoms and at least 4 carbon atoms between non-conjugated double bonds, at least one of which is the terminal one.

With respect to suitable polymeric materials for the polymer composition, said polyethylene may be any polymer having the relevant features described herein as the polyethylene for the exemplary polymer composition. The polyethylene may be selected from homopolymers of polyethylene as well as copolymers of polyethylene with one or more comonomers. Polyethylene may be unimodal or multimodal in terms of molecular weight distribution and/or comonomer distribution, and these expressions have a commonly known meaning.

In one embodiment, the polyethylene is an ethylene homopolymer.

In one embodiment of the present invention, a polymer composition obtained by a process including the use of polyethylene is described.

In an exemplary embodiment, the polyethylene is an unsaturated copolymer of polyethylene with at least one polyunsaturated comonomer and optionally one or more other comonomers.

Said unsaturated polyethylene copolymer is an unsaturated ethylene copolymer.

In one embodiment of the present invention, there is provided a polyethylene described herein that is a copolymer of a monomer with at least one polyunsaturated comonomer and zero, one or more, for example, zero, one, two, or three other comonomers, and wherein said total number of vinyl groups (B) present in the polyethylene includes vinyl groups sourced from at least one said polyunsaturated comonomer, for example a diene.

In an exemplary embodiment, polyethylene is produced by a process including the use of an ethylene unsaturated copolymer.

Said ethylene copolymer may be a 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.

The optional additional comonomer(s) present in the polyethylene, e.g., ethylene copolymer, is different from the skeletal monomer, and may be selected from ethylene and higher alpha olefin(s), e.g., C ₃ -C ₂₀ alpha olefin(s) ), for example, a cyclic alpha olefin containing from 5 to 12 carbon atoms, or from a straight or branched alpha olefin containing from 3 to 12 carbon atoms, such as propylene, 1-butene, 1-hexene, 1-nonene or 1-octene, as well as from polar comonomer(s).

In one embodiment, the straight or branched alpha olefin is a straight or branched alpha olefin containing from 3 to 6 carbon atoms.

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

It is well known that, for example, propylene can be used as a comonomer or as a chain transfer agent (CTA), or as both, and therefore can contribute to the total number of vinyl groups, B. In this context, when using a copolymerizable CTA, such as propylene, copolymerized CTA is not included in the calculation of comonomer content.

In an exemplary embodiment, the polyethylene is an unsaturated LDPE polymer, for example, an unsaturated LDPE copolymer containing at least one comonomer that is a polyunsaturated comonomer (herein referred to as a LDPE copolymer).

In addition, said polyunsaturated comonomer may be a diene, for example, (1) a diene that contains at least 8 carbon atoms, the first carbon-carbon double bond being terminal and the second carbon-carbon double bond not conjugate to the first (group 1 dienes). Exemplary dienes (1) may be selected from C ₈ -C ₁₄ non-conjugated 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, diene (1) is selected from 1,7-octadiene, 1,9-decadiene, 1,11-dodecadiene, 1,13-tetradecadiene, or mixtures thereof.

An additional embodiment of the present invention is provided herein, wherein the polyethylene is a copolymer of a monomer with at least one polyunsaturated comonomer, wherein the polyunsaturated comonomer has a straight carbon chain containing at least 8 carbon atoms, and at least 4 carbon atoms between non-conjugated double bonds, at least one of which is terminal, for example a C ₈ -C ₄ non-conjugated diene, for example selected from 1,7-octadiene, 1,9-decadiene, 1,11-dodecadiene, 1,13- tetradecadiene or mixtures thereof.

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

An additional embodiment of the present invention is provided herein, wherein the polyethylene is an unsaturated LDPE homopolymer or copolymer produced by a continuous high pressure polymerization process, for example, an LDPE copolymer of ethylene with one or more polyunsaturated comonomers and zero, one or more than other comonomers.

In addition to or as an alternative to the dienes (1) listed herein, the diene may also be selected from other types of polyunsaturated dienes (2), for example, one or more siloxane compounds having the following formula (dienes of group (2)):

CH2=CH-[SiR1R2-O] _n -SiR1R2-CH=CH2, where n = from 1 to 200 and

R1 and _R2 , which may be the same or different, are selected from C1- _C4 alkyl groups and/or C1- _C4 alkoxy groups.

In addition, R1 and/or _R2 may be, for example, methyl, methoxy or ethoxy. In addition, n can be, for example, from 1 to 100, for example from 1 to 50. As an example, mention may be made of divinylsiloxanes, for example α,ω-divinylsiloxane.

Exemplary polyunsaturated polyethylene comonomers are dienes from group (1) described herein. The polyethylene may be, for example, 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. An example is also given that said polyethylene is an unsaturated LDPE copolymer mentioned in this context. It may contain additional comonomers, for example, polar comonomer(s), alpha-olefin comonomer(s), non-polar comonomer(s), or any mixture thereof.

As the polar comonomer, a compound(s) containing hydroxyl group(s), alkoxy group(s), carbonyl group(s), carboxyl group(s), ether group(s) or ester group(s), or a mixture of them.

In addition, a non-polar comonomer is a compound(s) containing neither hydroxyl group(s), nor alkoxy group(s), nor carbonyl group(s), nor carboxyl group(s), nor ether group(s), nor ester group(s).

In a further embodiment, compounds containing carboxyl and/or ester group(s) are used and, for example, said compound is selected from acrylate(s), methacrylate(s) or acetate(s), or any mixtures thereof.

If LDPE is present in said unsaturated copolymer, the polar comonomer may, for example, be selected from the group of alkyl acrylates, alkyl methacrylates or vinyl acetate, or a mixture thereof. In addition, said polar comonomers may, for example, be selected from C1- _C6 alkyl acrylates, C1-C6 alkyl methacrylates or vinyl acetate. Moreover, said polar copolymer includes a copolymer of ethylene with a C1- _C4 alkyl acrylate, for example, methyl, ethyl, propyl or butyl acrylate, or vinyl acetate, or any mixture thereof. Moreover, said polar copolymer preferably includes a copolymer of ethylene with a C1- _C4 alkyl acrylate, for example methyl, ethyl, propyl or butyl acrylate, or any mixture thereof.

Polyethylene suitable for use in, for example, any polymer composition described herein can be produced using, among other things, any conventional polymerization process and equipment, conventional means described herein for providing unsaturation, and any conventional means for changes in PTR2 to regulate and select technological conditions to achieve the required balance between PTR2 and the number of vinyl groups in the polymerized polymer. An unsaturated LDPE polymer as defined herein, for example an unsaturated LDPE copolymer, is produced in a continuous high pressure reactor, for example a continuous high pressure tubular reactor, by free radical initiated polymerization (with respect to radical polymerization at

- 7 045796 high pressure). Suitable high pressure (HP) polymerization and control of process conditions are known and described in the literature and can be readily used by those skilled in the art to achieve the balance described herein. Continuous high pressure polymerization can be carried out in a tubular reactor or in an autoclave reactor, e.g. Described herein is one embodiment of a continuous HP process for polymerizing ethylene, optionally together with one or more comonomers, for example at least one or more polyunsaturated comonomers, in a tubular reactor to produce the LDPE homopolymer or copolymer described herein. This process can also be adapted for other polymers.

Compression.

Ethylene is supplied to the compressor primarily to enable large quantities of ethylene to be handled at controlled pressure and temperature. Compressors are usually reciprocating compressors or diaphragm compressors. A compressor is usually a group of compressors that can operate in series or in parallel. Most often, 2-5 compression stages are used. Recycled ethylene and comonomers can be added at accessible points, depending on pressure. The temperature is usually low, usually less than 200°C or less than 100°C. Said temperature may be, for example, less than 200°C.

Tubular reactor.

The resulting mixture is fed into a tubular reactor. The first part of the pipe is designed to change the temperature of the ethylene feedstock; the usual temperature is 150-170°C. A radical initiator is then added. Any compound or mixture that decomposes into radicals at elevated temperature can be used as a radical initiator. Suitable radical initiators are commercially available. The polymerization reaction is exothermic. There may be several radical initiator supply points, for example 1-5 points, which are usually equipped with separate metering pumps. In addition, ethylene and optional comonomer(s) may also be added at any time during the process to any zone of the tubular reactor and/or from one or more injection points as known to those skilled in the art. The reactor is continuously cooled, for example with water or steam. The highest temperature is called the peak temperature, and the lowest temperature is called the radical initiator temperature. The lowest temperature in this context means the temperature at which the reaction begins, which is called the initiation temperature, which is lower, as understood by those skilled in the art.

Suitable temperature ranges from 80 to 350°C and pressure from 100 to 400 MPa. The pressure can be measured at least during the compression stage and after the tubular reactor. Temperature can be measured at several points throughout all stages. High temperature and high pressure usually increase yield. The use of different temperature profiles selected by one skilled in the art allows the polymer chain structure, such as long chain branching and/or short chain branching, density, MFR, viscosity, molecular weight distribution, etc. to be controlled.

Typically, the reactor ends with a valve. The valve regulates the pressure in the reactor and ensures that the pressure of the reaction mixture decreases from the reaction pressure to the separation pressure.

Separation.

Typically the pressure is reduced to a value of about 10-45 MPa, for example to a value of about 30-45 MPa. The polymer is separated from unreacted products, eg, gaseous products such as monomer or optional comonomer(s), and most of the unreacted products are recovered. Low molecular weight compounds are usually isolated from gas, i.e. wax. You can continue to lower the pressure to recover and recycle unused gaseous products such as ethylene. The gas is usually cooled and purified before being returned to the cycle.

The resulting polymer melt is then typically mixed and granulated. Optionally, or in some embodiments, additives may be added to the mixer. Additional information on the preparation of ethylene (co)polymers by high pressure radical polymerization is presented in Encyclopedia of Polymer Science and Engineering, Vol. 6 (1986), pp. 383-410.

The MFI ₂ of a polyethylene, for example a LDPE copolymer, can be controlled by, for example, chain transfer agent(s) during polymerization and/or by adjusting the reaction temperature or pressure.

In preparing the LDPE copolymer of the present invention, as is known, the amount of vinyl groups can be controlled by polymerizing ethylene, for example, in the presence of one or more polyunsaturated comonomers, chain transfer agents, or both, by the desired feed ratio between C ₂ and polyunsaturated comonomer and/ or chain transfer agent, depending on the nature and number of double carbon bonds required for the LDPE copolymer. Among other things, WO 9308222 describes high pressure radical polymerization of ethylene with polyunsaturated monomers such as α,ω-alkadienes to increase the

- 8 045796 saturation of ethylene copolymer. Thus, unreacted double bond(s) provide pendant vinyl groups in the formed polymer chain at the site where the polyunsaturated comonomer is introduced during polymerization. As a result, unsaturation can be uniformly distributed along the polymer chain in a statistical copolymerization order. In addition, for example, WO 9635732 describes high pressure radical polymerization of ethylene and certain types of polyunsaturated α,ω-divinylsiloxanes. In addition, as is known, it is possible to use, for example, propylene as a chain transfer agent to provide double bonds, whereby it can also partially copolymerize with ethylene.

An alternative unsaturated LDPE homopolymer can be prepared similarly to the method for preparing the unsaturated LDPE copolymer described herein, except that the ethylene is polymerized in the presence of only a chain transfer agent.

One exemplary polyethylene, for example, a LDPE copolymer according to the present invention may have a density, measured for polyethylene in accordance with ISO 1183-1, Method A:2012, of, for example, greater than 0.860 g/cm ³ , greater than 0.870, greater than 0.880, greater 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 .

Another exemplary polyethylene, such as the LDPE copolymer of the present invention, may have a density, measured for polyethylene in accordance with ISO 1183-1, Method A:2012, of up to 0.960 g/cm ³ , 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/cm ³ .

In a further embodiment, the density range measured on polyethylene in accordance with ISO 1183-1, Method A:2012 is from 0.915 to 0.930 g/cm ³ .

In addition, the specified unsaturated copolymer, for example, a copolymer of LDPE, polyethylene contains comonomer(s) 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% wt. relative to the amount of polyethylene. In addition, the specified unsaturated copolymer, for example, a copolymer of LDPE, polyethylene preferably contains comonomer(s) in a total amount of from 0.1 to 5% by weight. relative to the amount of polyethylene.

An exemplary polyethylene may be formulated into a polymer composition as described herein, wherein said polymer composition is crosslinkable.

In an illustrative embodiment, the polymer composition described herein consists of at least one polyethylene. The polymer composition may also contain additional components, such as additives described herein, which can be added in mixtures with the polymer carrier, i.e. in the so-called super concentrate.

In a further embodiment, the polymer composition described herein may comprise polyethylene as described herein, together with a cross-linking agent and together with 0, 1, 2, 3, 4, 5, 6 or more additives, and wherein said polymer the composition is presented in the form of pellets.

In another embodiment of the present invention described herein, there is provided a polyethylene containing a total number of vinyl groups, which is the value B of vinyl groups per 1000 carbon atoms, and B1 < B, where B1 is 0.89, when measured before crosslinking according to with ASTM D6248-98 method.

In an additional embodiment, a polyethylene is described in which B1 is equal to 0.90. In an additional embodiment, a polyethylene is described in which B1 is equal to 0.94. In an additional embodiment, a polyethylene is described in which B1 is equal to 0.95. In a further embodiment, a polyethylene is described in which B1 is equal to 1.00.

Additional embodiments disclose polyethylene in which B1 is 0.95, 1.00, 1.05, or 1.10.

Additional embodiments describe polyethylene in which B1 is 0.95, 1.00, 1.05, 1.10, 1.15, 1.20, 1.25, or 1.30.

Additional embodiments provide polyethylene in which B1 is 1.15, 1.20, 1.25, or 1.30.

In an additional embodiment, a polyethylene is described in which B1 is equal to 1.05. In an additional embodiment, a polyethylene is described in which B1 is equal to 1.10. In an additional embodiment, a polyethylene is described in which B1 is equal to 1.15. In an additional embodiment, a polyethylene is described in which B1 is equal to 1.20. In an additional embodiment, a polyethylene is provided in which B1 is equal to 1.25. In a further embodiment, a polyethylene is described in which B1 is equal to 1.30.

In an additional embodiment of the present invention described herein, a polyethylene is provided wherein B < B ₂ and B ₂ is 3.0.

Additional embodiments of polyethylene are described in which said polyethylene contains a total number of vinyl groups, which is the value B of vinyl groups per 1000 carbon atoms, and B1 < B < B ₂ , where each B1 and B ₂ can be selected from any of the values given in this document for B1 and B ₂ , respectively.

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In an additional embodiment of the present invention described herein, a polyethylene is provided in which B2 is equal to 2.5.

In an additional embodiment of the present invention described herein, a polyethylene is provided in which B ₂ is equal to 2.0.

In an additional embodiment of the present invention described herein, a polyethylene is provided in which B ₂ is equal to 1.8.

In an additional embodiment of the present invention described herein, a polyethylene is provided in which B ₂ is equal to 1.7.

In an additional embodiment of the present invention described herein, a polyethylene is provided wherein B ₂ is equal to 1.6.

In an additional embodiment of the present invention described herein, a polyethylene is provided in which B2 is equal to 1.5.

In one embodiment of the present invention, a polyethylene is provided having a melt flow index under load of 2.16 kg (MFR ₂ ), and the specified MFR ₂ is equal to A g/10 min. and A1 < A < A ₂ ; where A1 equals 0.05 and A ₂ equals 1.70, when measured in accordance with the ISO 1133-1:2011 method, see details of the ISO 1133-1:2011 method in the description of Melt Flow Index in the Measurement Methods section.

MFI ₂ is determined before any crosslinking in accordance with ISO 1133-1:2011 with a load of 2.16 kg and at 190°C.

In a further embodiment of the present invention, the polyethylene described herein has a melt flow index at a load of 2.16 kg (MFR2) and at 190° C., measured in accordance with the ISO 1133-1:2011 method, and the specified MFR ₂ is equal to A g/10 min, with A < A ₂ , where A ₂ is equal to 10.

In an additional embodiment of the present invention described herein, a polyethylene is provided in which A ₂ is equal to 5.0.

In an additional embodiment of polyethylene, A ₂ is 4.0.

In an additional embodiment of the present invention described herein, a polyethylene is provided in which A2 is equal to 3.0.

In an additional embodiment of the present invention described herein, a polyethylene is provided in which A2 is equal to 2.7.

In an additional embodiment of the present invention described herein, a polyethylene is provided wherein A ₂ is equal to 2.5.

In an additional embodiment of the present invention described herein, a polyethylene is provided in which A ₂ is equal to 2.0.

In an additional embodiment of the present invention described herein, a polyethylene is provided in which A ₂ is equal to 1.7.

In a further embodiment, the polyethylene has a melt flow index, MFR ₂ , which is equal to A g/10 min, and A1 <A; where A1 is equal to 0.05.

Additional options for the implementation of polyethylene are described that have a melt flow rate, MFR ₂ , which is equal to A g/10 min, and A1 < A < A ₂ ; wherein each A1 and _A2 may be selected from any of the values given herein for A1 and _A2 , respectively.

In one embodiment of the present invention described herein, a polyethylene is provided in which A1 is equal to 0.10.

In one embodiment of the present invention described herein, a polyethylene is provided in which A1 is equal to 0.15.

In one embodiment of the present invention described herein, a polyethylene is provided in which A1 is equal to 0.20.

In one embodiment of the present invention described herein, a polyethylene is provided in which A1 is equal to 0.25.

In one embodiment of the present invention described herein, a polyethylene is provided in which A1 is equal to 0.30.

In one embodiment of the present invention described herein, a polyethylene is provided in which A1 is equal to 0.35.

In one embodiment of the present invention described herein, a polyethylene is provided in which A1 is equal to 0.40.

In one embodiment of the present invention described herein, a polyethylene is provided in which A1 is equal to 0.45.

In one embodiment of the present invention described herein, a polyethylene is provided in which A1 is equal to 0.50.

In one embodiment of the present invention described herein, a polyethylene is provided in which A1 is equal to 0.55.

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In one embodiment of the present invention described herein, a polyethylene is provided in which A ₁ is equal to 0.60.

In one embodiment of the present invention described herein, a polyethylene is provided in which A1 is equal to 0.65.

In one embodiment of the present invention described herein, a polyethylene is provided in which A1 is equal to 0.70.

In one embodiment of the present invention described herein, a polyethylene is provided in which A ₁ is equal to 0.75.

In one embodiment of the present invention described herein, a polyethylene is provided in which A1 is equal to 0.80.

In one embodiment of the present invention described herein, a polyethylene is provided in which A1 is equal to 0.85.

In one embodiment of the present invention described herein, a polyethylene is provided in which A1 is equal to 0.90.

In one embodiment of the present invention described herein, a polyethylene is provided in which A2 is equal to 1.65, 1.60, 1.55 or 1.50.

In an additional embodiment of the present invention described herein, a polyethylene is provided wherein A ₂ is equal to 1.65.

In one embodiment of the present invention described herein, a polyethylene is provided in which A ₂ is equal to 1.60.

In one embodiment of the present invention described herein, a polyethylene is provided in which A2 is equal to 1.65 or 1.60.

In one embodiment of the present invention described herein, a polyethylene is provided in which A2 is equal to 1.55.

In one embodiment of the present invention described herein, a polyethylene is provided wherein A ₂ is equal to 1.50.

In one embodiment of the present invention described herein, a polyethylene is provided wherein A ₂ is equal to 1.55 or 1.50.

Additional embodiments are described in which the polyethylene has a complex viscosity (η*) at 0.05 rad/s, measured in accordance with the ISO 6721-1 method on stabilized polyethylene samples, which is the value of X, Pa-s, and X1 < X < X ₂ , where each X 1 and X ₂ can be selected from any of the values given herein for X ₁ and X ₂ , respectively.

Additional embodiments of polyethylene are described in which the polyethylene has a complex viscosity (η*) at 300 rad/s, measured in accordance with the ISO 6721-1 method on stabilized polyethylene samples, which is the value of Y, Pa-s, and Y1 < Y < Y2, where each Y ₁ and Y ₂ can be selected from any of the values given herein for Y ₁ and Y ₂ , respectively.

In one embodiment of the present invention described herein, a polyethylene is provided wherein X1 is equal to 11000.

In one embodiment of the present invention described herein, a polyethylene is provided wherein X1 is equal to 12,000.

In one embodiment of the present invention described herein, a polyethylene is provided where X1 is equal to 13,000.

In one embodiment of the present invention described herein, a polyethylene is provided wherein X1 is equal to 14,000.

In one embodiment of the present invention described herein, a polyethylene is provided wherein X ₂ is equal to 29,000.

In one embodiment of the present invention described herein, a polyethylene is provided wherein X ₂ is equal to 28,000.

In one embodiment of the present invention described herein, a polyethylene is provided which has an X2 of 27,000.

In one embodiment of the present invention described herein, a polyethylene is provided which has an X2 of 26,000.

In one embodiment of the present invention described herein, a polyethylene is provided wherein X ₂ is equal to 25,000.

In one embodiment of the present invention described herein, a polyethylene is provided wherein X ₂ is equal to 24,000.

In one embodiment of the present invention described herein, a polyethylene is provided wherein X ₁ is equal to 15,000.

In one embodiment of the present invention described herein, a polyethylene is provided wherein X1 is equal to 16,000.

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In one embodiment of the present invention described herein, a polyethylene is provided wherein X1 is equal to 17,000.

In one embodiment of the present invention described herein, a polyethylene is provided wherein X1 is equal to 18,000.

In one embodiment of the present invention described herein, a polyethylene is provided where X1 is equal to 18100.

In one embodiment of the present invention described herein, a polyethylene is provided where X1 is equal to 18200.

In one embodiment of the present invention described herein, a polyethylene is provided which has an Xi of 18300.

In one embodiment of the present invention described herein, a polyethylene is provided wherein X1 is equal to 18400.

In one embodiment of the present invention described herein, a polyethylene is provided where X1 is equal to 18500.

In one embodiment of the present invention described herein, a polyethylene is provided where X1 is equal to 18600.

In one embodiment of the present invention described herein, a polyethylene is provided where X1 is equal to 18700.

In one embodiment of the present invention described herein, a polyethylene is provided whose X ₂ is equal to 23,500.

In one embodiment of the present invention described herein, a polyethylene is provided that has an X2 of 23,000.

In one embodiment of the present invention described herein, a polyethylene is provided whose X ₂ is equal to 22900.

In one embodiment of the present invention described herein, a polyethylene is provided wherein X ₂ is equal to 22800.

In one embodiment of the present invention described herein, a polyethylene is provided wherein X ₂ is equal to 22,700.

In one embodiment of the present invention described herein, a polyethylene is provided wherein X ₂ is equal to 22600.

In one embodiment of the present invention described herein, a polyethylene is provided that has an X2 of 22,500.

In one embodiment of the present invention described herein, a polyethylene is provided that has an X2 of 22,400.

In one embodiment of the present invention described herein, a polyethylene is provided which has an X2 of 22300.

In one embodiment of the present invention described herein, a polyethylene is provided wherein X ₂ is equal to 22,000.

In one embodiment of the present invention described herein, a polyethylene is provided whose X ₂ is equal to 21,500.

In one embodiment of the present invention described herein, a polyethylene is provided whose X ₂ is equal to 21,000.

In one embodiment of the present invention described herein, a polyethylene is provided which has an X2 of 20,500.

In one embodiment of the present invention described herein, a polyethylene is provided which has an X2 of 20,000.

In one embodiment of the present invention described herein, a polyethylene is provided that has an X2 of 19,500.

In one embodiment of the present invention described herein, a polyethylene is provided wherein X ₂ is equal to 19,000.

In one embodiment of the present invention described herein, a polyethylene is provided where Y1 is equal to 10.

In one embodiment of the present invention described herein, a polyethylene is provided wherein Y ₁ is equal to 20.

In one embodiment of the present invention described herein, a polyethylene is provided where Y1 is equal to 30.

In one embodiment of the present invention described herein, a polyethylene is provided that has a Y1 of 40.

In one embodiment of the present invention described herein, a polyethylene is provided where Y1 is equal to 50.

In one embodiment of the present invention described herein, a polyethylene is provided that has a Y ₁ of 60.

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In one embodiment of the present invention described herein, a polyethylene is provided that has a Y1 of 70.

In one embodiment of the present invention described herein, a polyethylene is provided that has a Y1 of 80.

In one embodiment of the present invention described herein, a polyethylene is provided that has a Y1 of 90.

In one embodiment of the present invention described herein, a polyethylene is provided where Y1 is equal to 100.

In one embodiment of the present invention described herein, a polyethylene is provided that has a Y1 of 110.

In one embodiment of the present invention described herein, a polyethylene is provided which has a Y ₁ of 120.

In one embodiment of the present invention described herein, a polyethylene is provided which has a Y ₁ of 130.

In one embodiment of the present invention described herein, a polyethylene is provided which has a Y ₁ of 140.

In one embodiment of the present invention described herein, a polyethylene is provided which has a Y ₁ of 150.

In one embodiment of the present invention described herein, a polyethylene is provided wherein X ₁ is equal to 15,000 and/or Y ₁ is equal to 150.

In one embodiment of the present invention described herein, a polyethylene is provided which has a Y ₁ of 160.

In one embodiment of the present invention described herein, a polyethylene is provided that has a Y1 of 170.

In one embodiment of the present invention described herein, a polyethylene is provided which has a Y ₁ of 180.

In one embodiment of the present invention described herein, a polyethylene is provided which has a Y ₁ of 190.

In one embodiment of the present invention described herein, a polyethylene is provided that has a Y ₁ of 200.

In one embodiment of the present invention described herein, a polyethylene is provided which has a Y1 of 210.

In one embodiment of the present invention described herein, a polyethylene is provided where Y1 is equal to 220.

In one embodiment of the present invention described herein, a polyethylene is provided that has a Y1 of 230.

In one embodiment of the present invention described herein, a polyethylene is provided that has a Y ₁ of 240.

In one embodiment of the present invention described herein, a polyethylene is provided that has a Y ₁ of 250.

In one embodiment of the present invention described herein, a polyethylene is provided that has a Y ₂ of 345.

In one embodiment of the present invention described herein, a polyethylene is provided wherein Y1 is 50 and/or Y2 is 345.

In one embodiment of the present invention described herein, a polyethylene is provided that has a Y2 of 340.

In one embodiment of the present invention described herein, a polyethylene is provided that has a Y2 of 335.

In one embodiment of the present invention described herein, a polyethylene is provided that has a Y ₂ of 330.

In one embodiment of the present invention described herein, a polyethylene is provided which has a Y ₂ of 325.

In one embodiment of the present invention described herein, a polyethylene is provided which has a Y ₂ of 320.

In one embodiment of the present invention described herein, a polyethylene is provided that has a Y ₂ of 315.

In one embodiment of the present invention described herein, a polyethylene is provided which has a Y ₂ of 310.

In one embodiment of the present invention described herein, a polyethylene is provided that has a Y2 of 305.

In one embodiment of the present invention described herein, a polyethylene is provided which has a Y ₂ of 300.

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In one embodiment of the present invention described herein, a polyethylene is provided wherein X1 is equal to 12,000 and _X2 is equal to 28,000.

In one embodiment of the present invention described herein, there is provided a polyethylene whose X1 is 12,000 and X ₂ is 28,000, and whose Y1 is 250 and Y2 is 330.

In one embodiment of the present invention described herein, there is provided a polyethylene whose X1 is 13,000 and X ₂ is 27,000, and whose Y1 is 240 and Y2 is 340.

In one embodiment of the present invention described herein, there is provided a polyethylene whose X1 is 13,000 and X ₂ is 27,000, and whose Y1 is 250 and Y2 is 330.

In one embodiment of the present invention described herein, a polyethylene is provided wherein X1 is 16,000, _X2 is 24,000, Y1 is 250, and/or _Y2 is 330.

In one preferred embodiment, the proposed polyethylene simultaneously satisfies the following conditions:

B1 < B < B ₂ , where B1 is equal to 0.30 and B ₂ is equal to 1.5;

X1 < X < X ₂ , where X ₁ is equal to 16000 and X ₂ is equal to 24000; And

Y ₁ < Y < Y ₂ , where Y ₁ is 250 and Y ₂ is 330.

A polymer composition obtained from polyethylene or containing polyethylene.

A polymer composition derived from the polyethylene of the present invention, which can be crosslinked, is well suited for producing crosslinkable articles, for example, one or more crosslinkable cable layers, for example, one or more crosslinkable cable insulation layers, and said layers can subsequently be crosslinked.

In a further embodiment of the present invention described herein, there is provided a polymer composition that is crosslinkable or cross-linked, wherein said polymer composition contains or is derived from polyethylene as described herein.

The expression crosslinkable is well known and means that the specified polymer composition obtained from polyethylene can be crosslinked, for example, through the formation of radicals, with the formation of bridges, including between polymer chains.

The term cable in this context means cable or wire.

The polymer composition obtained from polyethylene or containing polyethylene additionally contains a cross-linking agent.

Said polymer composition may optionally contain additional component(s) containing vinyl groups, which then also contribute to the total amount of vinyl groups in the polymer composition.

A cross-linking agent in this context means any compound capable of forming radicals that can initiate a cross-linking reaction. For example, a cross-linking agent contains an -O-O- bond.

An additional embodiment of the specified polymer composition described in this document is proposed, in which the cross-linking agent contains peroxide, i.e. contains at least one peroxide unit per molecule of crosslinking agent, for example peroxide.

In a further embodiment, the crosslinking agent comprises a peroxide.

In a further embodiment, the crosslinking agent is a peroxide.

In addition, embodiments of the specified polymer composition proposed herein are described, in which a cross-linking agent, for example, peroxide, is present in an amount that represents the Z value, wt.%. relative to the total amount (100 wt.%) of the polymer composition, Z < Z ₂ , where Z ₂ is equal to 10, Z ₂ is equal to 6, Z ₂ is equal to 5 or Z ₂ is equal to 3.5.

In a further embodiment, Z1 < Z, where Z1 is equal to 0.01.

Additional embodiments of the present invention provide the polymer composition described herein wherein Z ₁ is 0.02, 0.04, 0.06, or 0.08.

In additional embodiments, the present invention provides a polymer composition described herein, wherein Z ₁ is equal to, for example, 0.1 or 0.2, and/or Z ₂ is equal to, for example, 3 or 2.6.

In additional embodiments, the present invention provides a polymer composition described herein wherein Z ₂ is 2.0, 1.8, 1.6, or alternatively 1.4.

In one embodiment of the crosslinking agent, such as peroxide, Z ₂ is equal to 1.2.

In additional embodiments, the present invention provides a polymer composition described herein wherein Z ₂ is 1.2, 1.1, 1.0, or alternatively 0.95.

In a further embodiment, Z ₂ is equal to 1.0.

In a further embodiment, Z ₂ is 0.98 or 0.96. In a further embodiment, Z ₂ is 0.98. In a further embodiment, Z ₂ is equal to 0.96. In a further embodiment, Z ₂ is 0.94, 0.92, or 0.90. In a further embodiment, Z ₂ is equal to 0.94. In a further embodiment, Z ₂ is equal to 0.92. In a further embodiment, Z ₂ is 0.90.

In a further embodiment, Z ₂ is equal to 0.88 or 0.86. In an additional embodiment, Z2 is equal to 0.88. In a further embodiment, Z2 is equal to 0.86. In a further embodiment, Z2 is 0.84, 0.82, or 0.80. In a further embodiment, Z2 is equal to 0.84. In a further embodiment, Z2 is equal to 0.82. In a further embodiment, Z2 is equal to 0.80.

In a further embodiment, Z2 is equal to 0.78 or 0.76. In a further embodiment, Z2 is equal to 0.78. In a further embodiment, Z2 is equal to 0.76. In a further embodiment, Z ₂ is equal to 0.74, 0.72, or 0.70. In a further embodiment, Z ₂ is equal to 0.74. In a further embodiment, Z ₂ is equal to 0.72. In a further embodiment, Z ₂ is equal to 0.70.

In a further embodiment, Z2 is equal to 0.68 or 0.66. In a further embodiment, Z2 is equal to 0.68. In a further embodiment, Z2 is equal to 0.66. In a further embodiment, Z2 is 0.64, 0.62, or 0.60. In a further embodiment, Z2 is equal to 0.64. In a further embodiment, Z2 is equal to 0.62.

The crosslinking agent, for example peroxide, is present in an amount representing the Z value, wt.%. relative to the total amount (100% wt.) of the specified polymer composition, and Z < Z ₂ , where Z2 is equal to 0.60.

In a further embodiment, Z2 is equal to 0.58 or 0.56. In a further embodiment, Z2 is equal to 0.58. In a further embodiment, Z2 is equal to 0.56. In a further embodiment, Z ₂ is 0.54, 0.52, or 0.50. In a further embodiment, Z ₂ is equal to 0.54. In a further embodiment, Z ₂ is equal to 0.52. In a further embodiment, Z ₂ is equal to 0.50.

In a further embodiment, Z2 is equal to 0.48 or 0.46. In a further embodiment, Z2 is equal to 0.48. In a further embodiment, Z2 is equal to 0.46.

In a further embodiment of the present invention described herein, there is provided a polymer composition in which the amount Z of a crosslinking agent, such as peroxide, has a Z2 value of 0.45.

In a further embodiment, the amount Z of the crosslinking agent, such as peroxide, has a Z2 value of 0.40.

In a further embodiment, the amount Z of the crosslinking agent, such as peroxide, has a Z2 value of 0.35.

Non-limiting examples of cross-linking agents include organic peroxides such as di-tert-amyl peroxide, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexine-3, 2,5-di(tert-butylperoxy)-2,5dimethylhexane , tert-butyl cumyl peroxide, di(tert-butyl) peroxide, dicumyl peroxide, butyl 4,4-bis(tert-butylperoxy)valerate, 1,1-bis-(tert-butylperoxy)-3,3,5-trimethylcyclohexane, tert -butylperoxybenzoate, dibenzoyl peroxide, bis-(tert-butylperoxyisopropyl)benzene, 2,5-dimethyl-2,5di(benzoylperoxy)hexane, 1,1-di(tert-butylperoxy)cyclohexane, 1,1-di(tert-amylperoxy) cyclohexane or any mixtures thereof.

In additional embodiments, the peroxide crosslinking agent may be selected, for example, from 2,5-dimethyl-2,5-di(tert-butylperoxy)hexine-3,2,5-di(tert-butylperoxy)-2,5 -dimethylhexane, di(tert-butylperoxyisopropyl)benzene, dicumyl peroxide, tert-butylcumyl peroxide, di(tert-butyl)peroxide or any mixtures thereof.

In a further embodiment, the crosslinking agent is a peroxide selected from dicumyl peroxide, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexine-3 and tert-butylcumyl peroxide, or any mixtures thereof.

In a further embodiment, the crosslinking agent contains a peroxide, which is dicumyl peroxide.

In a further embodiment, the crosslinking agent contains a peroxide, which is 2,5-dimethyl-2,5-di(tert-butylperoxy)hexine-3.

In a further embodiment, the crosslinking agent comprises percoside, which is tert-butyl cumyl peroxide.

In one embodiment, said polymer composition contains a cross-linking agent.

In additional embodiments, said polymer composition may also contain additional additive(s). Such additional additive(s) contains: unsaturated low molecular weight compound(s), for example:

The cross-linking accelerator(s) mentioned herein, including any given specific compound(s), which can increase the degree of cross-linking and/or the amount of vinyl groups in the polymer composition.

One or more scorch inhibitors (SR), which are defined herein as compounds that reduce the formation of carbon deposits during extrusion of a polymer composition using conventional extrusion temperatures, compared to the same polymer composition extruded without the compound. Scane inhibitors may also contribute to the total amount of vinyl groups in the polymer composition.

Unsaturated low molecular weight compound(s), such as crosslinking enhancer(s) and/or one or more scorch inhibitors (SRs), may also contribute to the total amount of vinyl groups in the polymer composition.

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The crosslinking accelerator may be a compound containing at least 2 unsaturated groups, such as an aliphatic or aromatic compound, ester, ether, amine or ketone, which contains at least 2 unsaturated groups, such as cyanurate, isocyanurate, phosphate, orthoformate , an aliphatic or aromatic ether or allylic ester of benzenetricarboxylic acid. Examples of esters, ethers, amines and ketones are compounds selected from the general groups of diacrylates, triacrylates, tetraacrylates, triallyl cyanurate, triallyl isocyanurate, 3,9-divinyl-2,4,8,10-tetra-oxaspiro[5,5] undecane (DVS), triallyl trimellitate (TATM) or K,K,K',K',K,K-hexaallyl-1,3,5-triazine-2,4,6-triamine (NATATA), or any mixtures thereof. The crosslinking accelerator may be added in a crosslinking amount of less than 2.0% by weight, such as less than 1.5% by weight, such as less than 1.0% by weight, such as less than 0.75% by weight, for example, less than 0.5 wt.%, and the lower limit is, for example, at least 0.05 wt.%, for example, at least 0.1 wt.%. relative to the weight of the polymer composition.

The scorch inhibitors (SR) may be, for example, unsaturated dimers of aromatic alpha-methyl-alkenyl monomers such as 2,4-diphenyl-4-methyl-1pentene, substituted or unsubstituted diphenylethylene, quinone derivatives, hydroquinone derivatives, monofunctional vinyl complexes and ethers, monocyclic hydrocarbons containing at least two or more double bonds, or mixtures thereof. For example, the scorch inhibitor may be selected from 2,4-diphenyl-4-methyl-1-pentene, substituted or unsubstituted diphenylethylene, or mixtures thereof.

The amount of scorch inhibitor may, for example, be equal to or greater than 0.005 wt.%. relative to the weight of the polymer composition. In addition, the amount of scorch inhibitor may be, for example, equal to or greater than 0.01% by weight, equal to or greater than 0.03% by weight, or equal to or greater than 0.04% by weight. relative to the weight of the polymer composition.

In addition, the amount of scorch inhibitor may be, for example, equal to or less than 2.0 wt.%, for example, equal to or less than 1.5 wt.%. relative to the weight of the polymer composition. In addition, the amount of scorch inhibitor may be, for example, equal to or less than 0.8% by weight, equal to or less than 0.75% by weight, equal to or less than 0.70% by weight, or equal to or less than 0. 60% wt. relative to the weight of the polymer composition. In addition, the amount of scorch inhibitor may be, for example, equal to or less than 0.55% by weight, equal to or less than 0.50% by weight, equal to or less than 0.45% by weight, or equal to or less than 0. 40% wt. relative to the weight of the polymer composition.

In addition, the amount of scorch inhibitor may be, for example, equal to or less than 0.35 wt.%, for example, equal to or less than 0.30 wt.%. relative to the weight of the polymer composition. In addition, the amount of scorch inhibitor may be, for example, equal to or less than 0.25% by weight, equal to or less than 0.20% by weight, equal to or less than 0.15% by weight, or equal to or less than 0. 10% wt. relative to the weight of the polymer composition. In addition, the amount of scorch inhibitor may be, for example, equal to or less than 0.15 wt.%, or equal to or less than 0.10 wt.%. relative to the weight of the polymer composition.

In addition, the amount of scorch inhibitor may be from 0.005 to 2.0% by weight, for example, from 0.005 to 1.5% by weight. relative to the weight of the polymer composition. Additional exemplary ranges are, for example, from 0.01 to 0.8% wt., from 0.03 to 0.75% wt., from 0.03 to 0.70% wt. or from 0.04 to 0.60% wt. relative to the weight of the polymer composition. Additionally, exemplary ranges are, for example, from 0.01 to 0.60, to 0.55, to 0.50, to 0.45, or alternatively to 0.40 wt.%, from 0.03 to 0 .55, alternatively, up to 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 . relative to the weight of the polymer composition.

In addition, scorch inhibitors (SR) can, for example, be selected from the graftable stable organic free radicals described in EP1699882, which include sterically hindered stable organic free radicals derived from amines: for example, hydroxy derivative 2,2,6 ,6-tetramethylpiperidinyloxy (TEMPO), e.g. 4-hydroxyTEMPO or bis-TEMPO (e.g. bis-(1-oxyl)-2,2,6,6-tetramethylpiperidin-4-yl)sebacate) and e.g. multifunctional molecules containing at least two nitroxyl groups derived from oxo-TEMPO, 4-hydroxy-TEMPO, 4-hydroxy-TEMPO ester, polymer-linked TEMPO, PROXYL, DOXYL, di-tert-butyl-K-oxyl, dimethyldiphenylpyrrolidine-1- oxyl or 4phosphonoxy-TEMPO.

Graftable organic stable free radicals, as described in EP1699882, may be present in an amount of exactly or more than about 0.005 percent by weight, for example, exactly or more than about 0.01 percent by weight, and exactly or more than about 0.03 percent by weight relative to the weight of the polymer composition.

In addition, graftable organic stable free radicals, as described in EP1699882, may be present in an amount equal to or less than about 20.0 percent by weight,

- 16 045796 for example, Exactly or less than about 10.0 percent by weight, for example, exactly or less than about 5.0 percent by weight, based on the weight of the polymer composition.

In addition, graftable organic stable free radicals, as described in EP1699882, may be present in an amount from about 0.005 percent by weight to about 20.0 percent by weight, for example, from about 0.01 percent by weight to about 10.0 percent by weight weight, for example, from about 0.03 weight percent to about 5.0 weight percent, based on the weight of the polymer composition.

In addition, said additional additive(s) includes additive(s) such as antioxidant(s), stabilizer(s) and/or processing aid(s). As the antioxidant, hindered or semi-hindered phenol(s), aromatic amine(s), aliphatic hindered amine(s), organic phosphate(s), thio compound(s) and mixtures thereof may be mentioned. As further additive(s), mention may be made of fire retardant additive(s), water tree retardant(s), acid neutralizer(s), filler(s), pigment(s) and voltage stabilizer(s).

Examples of suitable fillers and/or pigments include TiO ₂ , CaCO ₃ , carbon black (e.g., conductive carbon black or UV black, i.e., carbon black that absorbs ultraviolet radiation), ganite, mica, kaolin, aluminum hydroxide (ATH) , magnesium dihydroxide (MDH) and SiO ₂ .

In a further embodiment, said polymer composition according to the present invention further comprises fillers and/or pigments. In addition, said fillers and/or pigments may be contained in said polymer composition according to the present invention in an amount of, for example, from 0.01 to 5% by weight, for example, from 0.01 to 3% by weight. or, for example, from 0.01 to 2% wt.

Said polymer composition may further comprise additional polymer component(s), including unsaturated polymer(s) and/or polymer(s) that are not unsaturated, wherein said additional polymer component(s) are other than said polyethylene.

The specified polymer composition can be presented in the form of powder or pellets of any shape and size, including granules. Pellets can be obtained, for example, after polymerization of said polyethylene in a generally known manner using traditional pelletizing equipment such as a pelletizing extruder. The polymer composition can be presented, for example, in the form of pellets.

In a further embodiment, the present invention provides a method for preparing the polymer composition described herein.

In a further embodiment, the present invention provides a method for producing the polyethylene described herein or a method for producing the polymer composition described herein.

End Applications

In one embodiment of the present invention, there is provided an article produced by a process comprising the use of a polyethylene as described herein or a polymer composition as described herein, wherein said article is, for example, a cable, for example a power cable, for example a cable layer or , for example, a layer of power cable.

In a further embodiment, the present invention provides an article comprising layer(s) that are derived from the polyethylene described herein.

In a further embodiment of the present invention, there is provided an article comprising layer(s), for example an insulating layer(s), which is made from polyethylene as described herein, said article being, for example, a cable, for example a power cable.

In a further embodiment, the present invention provides an article comprising element(s), wherein said element(s) comprise layer(s), for example, insulating layer(s), which is derived from polyethylene as described herein, or from a polymer composition, described in this document.

In a further embodiment, the present invention provides an article, wherein said article or element(s) comprises layer(s), for example, insulation layer(s), which is crosslinkable and derived from polyethylene as described herein or from a polymer composition as described herein. in this document.

In a further embodiment, the present invention provides an article, wherein the article or element(s) comprises polyethylene as described herein or a polymer composition as described herein.

In a further embodiment, the present invention provides an article, wherein said article or element(s) comprises layer(s), for example, insulation layer(s), which is crosslinkable and derived from polyethylene as described herein or from a polymer composition as described herein. in this document.

In a further embodiment, the present invention provides an article, wherein said article or element(s) comprises a polymer composition described herein.

- 17 045796

In a further embodiment, the present invention provides an article, wherein said article or element(s) comprises layer(s), for example, insulating layer(s), which is cross-linked and derived from a polymer composition described herein.

In a further embodiment, the present invention provides an article that is a cable, such as a power cable.

In addition, the present invention is highly suitable for use in the cable and wire industry, the product being, for example, a cable that is crosslinkable and contains one or more layers, at least one layer being derived from a polyethylene or polymer composition described in this document.

In addition, a further embodiment of the present invention is provided, wherein said at least one layer comprises a polyethylene or polymer composition as described herein.

In a further embodiment, the present invention provides a power cable comprising layer(s), for example, insulating layer(s), which is derived from polyethylene or a polymer composition described herein.

An additional embodiment of the present invention is proposed, in which the specified product is an AC power cable.

An additional embodiment of the present invention is proposed, in which the specified product is a DC power cable.

In addition, at least one layer of the cable, made from polyethylene or a polymer composition, is, for example, an insulating layer.

In addition, at least one layer of the cable containing polyethylene or a polymer composition may be, for example, an insulating layer.

In addition, the cable according to the present invention may be, for example, a power cable that contains at least an inner semiconducting layer, an insulating layer and an outer semiconducting layer in that order, wherein at least the insulating layer is made from a polyethylene or a resin composition described in this document.

In a further embodiment, the insulating layer comprises polyethylene or a polymer composition described herein.

Power cable in this context means a cable capable of transmitting energy at any operating voltage. The voltage supplied to the power cable can be AC, DC or transient (pulse). In one embodiment, the proposed multilayer product is a power cable operating at voltages greater than 6 kV.

In a further embodiment, the present invention provides a method for producing the article described herein, comprising the use of a polyethylene or polymer composition described herein.

In addition, the present invention provides a method for producing the described article, which includes the steps of a) molding the article, which process includes the use of polyethylene or a polymer composition described herein.

The proposed method may include, for example, at least the steps of:

ao) melt mixing the polymer composition described herein, optionally together with additional component(s), and

a) forming a cable obtained from the polymer composition described herein.

In an additional embodiment, it is proposed to form a cable containing a polymer composition described herein.

Melt mixing is a generally known mixing method in which the polymer component(s) are mixed at an elevated temperature, which is typically higher, for example at least 20-25° C. above the melting or softening temperature of the polymer component(s).

In one embodiment, a cable is provided that includes a conductor surrounded by one or more layers, the method comprising the step of a) applying to the conductor a polymer composition described herein to form at least one of said layers surrounding the conductor.

Thus, in step (a) at least one layer of one or more layers is applied and formed using the polymer composition described herein.

In addition, an exemplary method for producing a cable may include, for example, at least two steps of a ₀ ) melt mixing said polymer composition described herein, optionally together with additional component(s), and then

a) applying the molten mixture obtained at stage AO) to the conductor to obtain at least one layer.

The polymer composition described herein can be introduced at stage ao) of the proposed method, for example, in the form of pellets, and mixing, i.e. melt mixing is carried out at an elevated temperature, which ensures melting (or softening) of the polymer material to enable its processing.

In addition, the layers can be, for example, a) applied by (co)extrusion. The term (co)extrusion in this context means that in the case of two or more layers, said layers can be extruded in separate stages, or at least two or all of said layers can be co-extruded in one extrusion stage, as is known in the art.

In one illustrative embodiment, the crosslinkable polymer composition may contain a crosslinker before the polymer composition is used to form a cable, wherein the polyethylene and the crosslinker may be mixed by any conventional mixing method, for example, by adding the crosslinker to a melt of the polymer composition, for example , in an extruder, and also by adsorption of liquid peroxide, peroxide in liquid form or peroxide dissolved in a solvent on a solid polymer composition, for example, on its pellets. Alternatively, in this embodiment, the polyethylene and crosslinking agent may be mixed by any conventional mixing method. Exemplary mixing methods include melt mixing, such as in an extruder, as well as adsorption of liquid peroxide, peroxide in liquid form, or peroxide dissolved in a solvent onto the polymer composition or onto its pellets. The resulting polymer composition of components, for example, inter alia, polyethylene and a cross-linking agent, is then used in the process of producing a product, for example a cable.

In another embodiment, a crosslinking agent may be added, for example, at step _a0 ) during the preparation of the crosslinkable article, and also forms the specified polymer composition according to the present invention. If the crosslinking agent is added during the production of the article, then, for example, the crosslinking agent described herein is added in liquid form at ambient temperature or preheated to a temperature above its melting point, or dissolved in a carrier medium, as is known in the art technology.

The polymer composition of the present invention may also contain additional additive(s), or the additional additive(s) may be mixed with the polymer composition during the production of an article containing the polymer composition.

Accordingly, the method according to the present invention may, for example, comprise the steps of:

a ₀₀ ) providing for said step a ₀ ) said polymer composition described herein, which contains at least one polyethylene and a cross-linking agent, and ₀ ) melt mixing the polymer composition, optionally along with additional components, and

a) applying the molten mixture obtained in step a0) to the conductor to obtain at least one of one or more of said cable layers.

Alternatively, the method according to the present invention includes the steps of:

a00) providing for said step a0) said polymer composition described herein that contains at least one polyethylene, and ₀₀ ') adding to said polymer composition at least one cross-linking agent, and ₀ ) melt mixing the polymer composition, and a crosslinking agent, optionally together with additional components, and

a) applying the molten mixture obtained in step _a0 ) to the conductor to form at least one of one or more of said cable layers.

In exemplary method _a0 ), separate melt mixing of the polymer composition is carried out in a mixer or extruder, or any combination thereof, at an elevated temperature, and if a crosslinking agent is present, also at a temperature below the crosslinking temperature used below. Then, after a ₀ ) melt mixing, for example in said extruder, the resulting melt-blended layer material is, for example: a) (co)extruded onto the conductor in a manner well known in the art. Mixers and extruders, such as single-screw or twin-screw extruders, which are typically used to produce cables, are suitable for the method according to the present invention.

An exemplary embodiment of the proposed method provides a crosslinkable cable, for example a crosslinkable power cable, wherein the proposed method includes the additional step of b) crosslinking at least one cable layer obtained in step a) containing a crosslinkable polyethylene or polymer composition, wherein the crosslinking is carried out in the presence of crosslinking agent, for example peroxide.

It is also clear and common knowledge that other cable layers and their materials, if any, can be cross-linked at the same time if necessary.

Crosslinking can be carried out under crosslinking conditions, typically by treatment at elevated temperature, for example above 140°C, for example above 150°C, for example 160 to 350°C, depending on the crosslinking agent used, as is known in the art field of technology. Typically the crosslinking temperature is at least 20°C higher than the temperature used in the step

- 19 045796 melt mixing a ₀ ), and a person skilled in the art can calculate it.

The result is a cross-linked cable containing at least one cross-linked layer of polyethylene or a polymer composition according to the present invention.

In a further embodiment of the present invention, said polymer composition is described, wherein the number of vinyl groups is determined (in addition to the vinyl groups due to free radical-induced polymerization):

i) polyunsaturated comonomer(s), ii) chain transfer agent(s), iii) unsaturated low molecular weight compound(s), such as crosslinking enhancer(s) and/or scorch inhibitor(s), or iv) any mixture of (i )-(iii).

In general, a vinyl group in this context means a CH2=CH- moiety, which may be present in any of i)-iv).

Said i) polyunsaturated comonomers and ii) chain transfer agents are described herein in relation to the polyethylene of the present invention.

Said iii) low molecular weight compound(s), if present, may be added to the polymer composition.

In addition, iii) the low molecular weight compound(s) may, for example, be crosslinking accelerator(s), which may also contribute to the total amount of vinyl groups of the polymer composition. The crosslinking accelerator(s) may be, for example, a compound(s) containing at least 2 unsaturated groups, such as an aliphatic or aromatic compound, an ester, an ether or a ketone that contains at least 2 unsaturated groups, such as cyanurate, isocyanurate, phosphate, orthoformate, aliphatic or aromatic ether or allyl ester of benzenetricarboxylic acid. Examples of esters, ethers, amines and ketones are compounds selected from the general groups of diacrylates, triacrylates, tetraacrylates, triallyl cyanurate, triallyl isocyanurate, 3,9-divinyl-2,4,8,10tetra-oxaspiro[5,5]undecane ( DVS), triallyl trimellitate (TATM) or N,N,N',N',N,N-hexααlyl1,3,5-triazine-2,4,6-triamine (NATATA), or any mixtures thereof. The crosslinking accelerator may be added in a crosslinking amount of less than 2.0% by weight, such as less than 1.5% by weight, such as less than 1.0% by weight, such as less than 0.75% by weight, for example, less than 0.5 wt.%, and the lower limit is, for example, at least 0.05 wt.%, for example, at least 0.1 wt.%. relative to the weight of the polymer composition.

In addition, iii) the low molecular weight compound(s) may be, for example, scorch inhibitor(s), which may also contribute to the total amount of vinyl groups in the polymer composition.

The scorch inhibitors (SR) may be, as already described herein, unsaturated dimers of aromatic alpha-methyl-alkenyl monomers such as 2,4-diphenyl-4-methyl-1-pentene, substituted or unsubstituted diphenylethylene, quinone derivatives , hydroquinone derivatives, monofunctional vinyl-containing esters and ethers, monocyclic hydrocarbons containing at least two or more double bonds, or mixtures thereof. For example, the scorch inhibitor may be selected from 2,4-diphenyl-4methyl-1-pentene, substituted or unsubstituted diphenylethylene, or mixtures thereof.

The amount of scorch inhibitor may, for example, be equal to or greater than 0.005 wt.%. relative to the weight of the polymer composition. In addition, the amount of scorch inhibitor may be, for example, equal to or greater than 0.01% by weight, equal to or greater than 0.03% by weight, or equal to or greater than 0.04% by weight. relative to the weight of the polymer composition.

In addition, the amount of scorch inhibitor may be, for example, equal to or less than 2.0 wt.%, for example, equal to or less than 1.5 wt.%. relative to the weight of the polymer composition. In addition, the amount of scorch inhibitor may be, for example, equal to or less than 0.8% by weight, equal to or less than 0.75% by weight, equal to or less than 0.70% by weight, or equal to or less than 0. 60% wt. relative to the weight of the polymer composition. In addition, the amount of scorch inhibitor may be, for example, equal to or less than 0.55% by weight, equal to or less than 0.50% by weight, equal to or less than 0.45% by weight, or equal to or less than 0. 40% wt. relative to the weight of the polymer composition.

In addition, the amount of scorch inhibitor may be, for example, equal to or less than 0.35 wt.%, for example, equal to or less than 0.30 wt.%. relative to the weight of the polymer composition. In addition, the amount of scorch inhibitor may be, for example, equal to or less than 0.25% by weight, equal to or less than 0.20% by weight, equal to or less than 0.15% by weight, or equal to or less than 0. 10% wt. relative to the weight of the polymer composition. In addition, the amount of scorch inhibitor may be, for example, equal to or less than 0.15 wt.%, or equal to or less than 0.10 wt.%. relative to the weight of the polymer composition.

- 20 045796

In addition, the amount of scorch inhibitor may be from 0.005 to 2.0% by weight, for example, from 0.005 to 1.5% by weight. relative to the weight of the polymer composition. Additional exemplary ranges are, for example, from 0.01 to 0.8% wt., from 0.03 to 0.75% wt., from 0.03 to 0.70% wt. or from 0.04 to 0.60% wt. relative to the weight of the polymer composition. Additionally, exemplary ranges are, for example, from 0.01 to 0.60, to 0.55, to 0.50, to 0.45, or alternatively to 0.40 wt.%, from 0.03 to 0 .55, alternatively, up to 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 . relative to the weight of the polymer composition.

In addition, scorch inhibitors (SR), for example, can also be selected from the graftable organic stable free radicals described in EP1699882, as well as those already described herein.

The polyethylene may be, for example, a copolymer of monomer units with at least one unsaturated comonomer(s) and zero, one, two or three other comonomers, and contains at least vinyl groups due to the polyunsaturated comonomer.

In addition, polyethylene may contain from about 0.05 to about 0.10 vinyl groups per 1000 carbon atoms (C atoms), which are due to free radical-induced polymerization.

In accordance with the present invention, each feature of any of the embodiments described herein, in any category of the present invention, can be freely combined with any feature of any other embodiments described herein.

Methods of measurement.

Unless otherwise indicated in the description or experimental part, the following methods were used to measure properties.

Melt fluidity index.

The melt flow index (MFI) is determined in accordance with the ISO 1133-1:2011 method and is expressed in g/10 min. MFR is an indicator of the fluidity and, therefore, the manufacturability of a polymer, in this case polyethylene or a polymer composition. The higher the melt flow rate, the lower the viscosity of the polymer or polymer composition. The MFR is determined at 190°C for polyethylenes and can be determined at different loads such as 2.16 kg (MTR ₂ ) or 21.6 kg (MTR ₂₁ ).

Density.

Density is measured on a polymer sample, i.e. polyethylene, in accordance with ISO 1183-1, method A:2012. The sample is obtained by pressing in a mold in accordance with ISO 17855-2:2016.

ASTM D3124-98 and ASTM D6248-98 methods for determining the number of double bonds in a polymer composition or polymer, i.e. in polyethylene.

ASTM D6248-98 method is used to determine the number of double bonds in a polymer composition and in polyethylene. Determination of the number of double bonds in a polymer composition is carried out on a sample of polyethylene or, alternatively, a polymer composition. In the following, when describing this method, the polymer composition and polyethylene are referred to as the composition and the polymer, respectively.

The ASTM D3124-98 and ASTM D6248-98 methods include, on the one hand, a method for determining the number of double bonds/1000 C atoms, which is based on the ASTM D3124-98 method. ASTM Method D3124-98 provides a detailed description of the determination of vinylidene groups/1000 C atoms using 2,3-dimethyl-1,3-butadiene. ASTM Method D6248-98 provides a detailed description of the determination of vinyl and trans-vinylene groups/1000 C atoms using 1-octene and trans-3hexea, respectively. The sample preparation method described in the above documents is used in this context to determine the content of vinyl groups/1000 C atoms and trans-vinylene groups/1000 C atoms according to the present invention. The ASTM D6248-98 method suggests the possible inclusion of a bromination procedure for the ASTM D3124-98 method, but the samples of the present invention were not brominated. The present inventors have shown that the determination of vinyl groups/1000 C atoms and trans-vinylene groups/1000 C atoms can be carried out without any significant obstacles, even without subtracting spectra from 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 method described in ASTM-D6248-98 was used, with the above exception.

The total number of vinyl bonds, vinylidene bonds and trans-vinylene double bonds of the polymer was analyzed by IR spectrometry and expressed as the number of vinyl bonds, vinylidene bonds and trans-vinylene bonds per 1000 carbon atoms.

In addition, the total number of vinyl and trans-vinylene double bonds of the composition, with a possible increase in the number of double bonds due to the unsaturated low molecular weight compound (iii) used, can also be analyzed using IR spectrometry, and the results are expressed as the number of vinyl bonds, vinylidene bonds and trans-vinylene bonds per 1000 carbon atoms.

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

The baseline was drawn from 980 cm ^-1 to approximately 840 cm ^-1 . Peak heights were determined at approximately 910 cm ^-1 for vinyl and approximately 965 cm ^-1 for trans-vinylene. The number of double bonds/1000 carbon atoms was calculated using the formulas:

vinyl/1000 atoms C = (14 x Abs)/(13.13 x L x D), trans-vinylene/1000 atoms C = (14 x Abs)/(15.14 x L x D), where Abs: absorption (peak height);

L: film thickness, mm;

D: material density (g/ ^cm3 ).

Molar extinction coefficient, ε, i.e. 13.13 and 15.14, respectively, in the calculations described above were determined in units of l-mol-mm ^-1 using the equation ε = Abs/(C x L), where Abs represents the maximum absorbance determined from the peak height;

C represents the concentration (mol-L ^-1 ) and

L represents the cell thickness (mm).

For polymers with polar comonomer content >0.4%, detection of unsaturated groups may be complicated by adjacent FT-IR peaks. An alternative baseline approach may provide a more accurate calculation of unsaturated group content.

Overall estimation of small peaks near larger peaks may result in an underestimation. Alternative baseline positions are 880 and 902 cm ^-1 for vinyl, 902 and 920 cm ^-1 for vinylidene, and 954 and 975 cm ^-1 . For higher levels of unsaturated groups, the vinyl and vinylidene baselines should be combined.

ASTM D3124-98 and ASTM D6248-98 methods, on the other hand, also include a method for determining the molar extinction coefficient. At least three solutions of 0.18 mol-L ^-1 in carbon diosulfide (CS2) were used and the average value for the molar extinction coefficient was used.

The number of vinyl groups due to the polyunsaturated comonomer per 1000 carbon atoms was determined and calculated as follows.

The test polymer and the reference polymer were prepared in the same reactor, usually using the same conditions, i.e. identical peak temperatures, pressures and production rates, with the only difference being that the polyunsaturated comonomer was added to the test polymer and not added to the reference polymer. The total number of vinyl groups in each polymer was determined by FT-IR measurements as described herein. Then it was assumed that the basic content of vinyl groups, i.e. vinyl groups formed as a result of the process and from the chain transfer agents providing the formation of vinyl groups (if present), is the same for the reference polymer and for the test polymer, with the only exception that the test polymer also contained a polyunsaturated comonomer added to reactor. This baseline value was then subtracted from the measured number of vinyl groups in the polymer being analyzed to obtain the number of vinyl groups/1000 C atoms due to the polyunsaturated comonomer.

ASTM D3124-98 and ASTM D6248-98 methods include a calibration procedure to measure the double bond content of the unsaturated small molecular compound (iii), if present (hereinafter referred to as compound).

The molar extinction coefficient of a compound (eg, a cross-linking accelerator or scorch inhibitor compound, exemplified herein) can be determined using these methods in accordance with ASTM D6248-98. At least three solutions of the compound in CS2 (carbon disulfide) were prepared. The solution concentrations used were close to 0.18 mol/L. Solutions were analyzed by FT-IR and spectra were recorded with a resolution of 4 cm ^-1 in a liquid cell with a path length of 0.1 mm. The maximum absorption peak intensity that relates to the unsaturated moiety of the compound(s) (each of the carbon-carbon double bond types present) was measured.

The molar extinction coefficient, ε, in l-mol ^-1 -mm ^-1 for each solution and type of double bond is calculated using the following equation:

ε = ( 1/CL ) x Abs, where C = concentration of each type of carbon-carbon double bond to be measured, mol/l;

L = cell thickness, mm;

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

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Calculate the average molar extinction coefficient, ε, for each type of double bond.

The average molar extinction coefficient, ε, for 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 being analyzed.

Rheology, dynamic method (viscosity determination) ISO 6721-1.

The dynamic rheological properties of a polymer, in this case polyethylene, or a polymer composition (also measured on polyethylene), can be determined using a controlled shear rheometer using a plane-parallel geometry (25 mm diameter) and a gap between the top and bottom plates of 1.8 mm. Before testing, samples must be stabilized by dry mixing the granules with 0.25-0.3% Irganox B225. Irganox B225 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. It should be noted that the addition of an antioxidant, in this case Irganox B225, is not a standard procedure for the ISO 6721-1 method.

Pressing in the mold is carried out under the following conditions: the granules are melted for 2 minutes at 190°C at any pressure, and then at a load of 100 kg/cm ² for 2 minutes. After pressing, the material is left to cool to room temperature, without releasing the pressure, for 30 minutes. The final thickness of the samples is 1.8 mm.

Sweep test, i.e. Rheology test, dynamic method (viscosity determination), was carried out in accordance with the standard ISO method, ISO 6721-1 with an angular frequency range from 500 to 0.02 rad/s. All experiments were carried out in a nitrogen atmosphere at a constant temperature of 190°C and tension in the linear viscoelastic region. During analysis, storage modulus (G'), loss modulus (G), complex modulus (G*) and complex viscosity (η*) were recorded and plotted against frequency (ω). The measured values of complex viscosity (η*) at angular frequencies of 0.05, 100 and 300 rad/s were taken from the test. These parameters are abbreviated as η* ₀ . ₀₅ , η* ₁₀₀ and η* ₃₀₀ , respectively.

The zero shear viscosity value η* ₀ was calculated using the Carreau-Yashida model. For those cases in which the use of such a model for estimating zero shear viscosity is not recommended, a rotational shear test was performed at zero shear rate. This test is limited to a shear rate range of 0.001 to 1 s ^-1 and a temperature of 190°C.

Receiving the cable, i.e. cable core, i.e. a cable produced using polyethylene according to the present invention, and a comparison cable.

Polymer granules of experimental polymer compositions, i.e. the polymer composition contained in the cable according to the present invention and the polymer composition contained in the reference cable were used to produce cables, i.e. cable cores, i.e. cable produced using the polyethylene according to the present invention, and a comparison cable on the Maillefer pilot cable line, which is a continuous vulcanization (CCV) chain line. The polymer beads contained polyethylene, antioxidant(s) and a cross-linking agent, in this case peroxide. The resulting cables had a nominal insulation thickness of 9.5 mm, derived from a polymer composition or a comparative polymer composition, and an inner semiconductive layer of 1.0 mm thickness, as well as an outer semiconductive layer of 1.0 mm thickness. The cable core wires were made of stranded aluminum and had a cross-section of 50 mm ² . Cables, i.e. cable cores were produced by extrusion through a triple die. The curing pipe consisted of 4 zones (Z1, Z2, Z3 and Z4), and the temperature used in each zone for cable extrusion was as follows: Z1=310°C, Z2=300°C, Z3=290°C and Z4= 290°C. Semiconductive material, i.e. the semiconductive composition used as the material for the inner and outer semiconductive layer was LE0592 (a commercially available semiconductor material supplied by Borealis). Cable cores were produced at a line speed of 1.5 m/min if the polymer granules of the insulating layer contained dicumyl peroxide (DCP) as the peroxide.

To determine elongation during thermal deformation, i.e. for testing by the method of determining thermal deformation, samples were taken from the middle of the insulating layer of the cable core, i.e. from a cross-linked cable according to the present invention, as well as from a cross-linked comparison cable. For a sample of experimental material in the shape of a dumbbell 1 mm thick, i.e. To determine the elongation during thermal deformation, a load with a mass corresponding to 20 N/cm ² was attached to the sample.

The thermal deformation method used for the cable sample, i.e. cable core, i.e. cable made using polyethylene according to the present invention, and a comparison cable

Elongation during thermal deformation, as well as permanent deformation, were determined on samples taken from the middle of the insulating layer of the cable core, i.e. layer(s) of a cross-linked cable according to the present invention, as well as a cross-linked reference cable obtained as described herein in the section Preparation of a cable core. These properties were determined in accordance with IEC 60811-507:2012. In a thermal deformation test on a dumbbell-shaped specimen, i.e. for sample ex

- 23 045796 perimental material, a load with a mass corresponding to 20 N/cm ² was attached. First, all samples were marked with control lines. Two control lines were made in the middle of each sample (one on each side). The distance between the two lines, L0, was 20 mm. A sample of the material was placed in an oven at 200°C with a mass corresponding to 20 N/cm ² and after 15 minutes the thermal elongation was measured as follows. The distance between the control lines was measured after 15 minutes at 200°C, designated L1. Then the elongation for 15 was calculated as follows: elongation at thermal deformation (%) = ((L1-100)/L0)-100. Then the load was removed and the sample was left to recover for 5 minutes at 200°C. The material sample was then removed from the oven and cooled to room temperature. After cooling, the distance L2 between the two reference lines was measured and the permanent strain was calculated as follows: permanent strain (%) = ((L2-100)/L0)-100.

Samples in the shape of a dumbbell, i.e. material samples were taken from the middle of the cable core insulation layer in accordance with IEC 60811-501:2012 and their thickness was 1 mm.

Assessment of cable sag resistance, i.e. cable core, i.e. cable obtained using polyethylene according to the present invention, and a comparison cable - the cable was prepared as described in this document in the section Preparation of the cable.

The cable core was cut into smaller pieces using a band saw and the wire was removed. Then the cable core sample was cut into pieces approximately 0.5 mm thick, and the thickness of the insulating layer was measured using a microscope. The portion of the insulation layer that has the greatest difference between the thickest and thinnest portions was determined and used as the sag resistance value.

Experimental part Examples

The polyethylenes were low density polyethylenes polymerized at high pressure in a continuous tubular reactor.

Example according to the invention 1. Polymer 1, i.e. polyethylene according to the present invention, i.e. poly(ethylene-co-1,7-octadiene) polymer containing 0.71 vinyl groups/1000 carbon atoms (C), density = 922.3 kg/m ³ , MFR ₂ = 0.68 g/10 min).

The CTA recirculated ethylene was compressed in a 5-stage pre-compression compressor and a 2-stage intercooled hypercompressor to achieve an initial reaction pressure of approximately 2900 bar. The total compressor power was about 30 t/h. In the compressor zone, approximately 1.2 kg/h of propionaldehyde (PA, CAS number: 123-38-6) and approximately 87 kg of propylene/h were added as chain transfer agents to maintain a MFI _of 0.68 g/10 min. In this case, 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 the preheating section of a three-zone front-loading tubular reactor having an internal diameter of about 40 mm and a total length of 1200 m. A mixture of commercially available peroxide radical initiators dissolved in isododecane was introduced immediately after the preheater in an amount sufficient for the exothermic polymerization reaction temperature to reach about 277°C, after which the mixture was cooled to about 206°C. The next temperatures ^{of its 2nd} and 3rd peaks were 270°C and 249°C, respectively, with intermediate cooling to 217°C. The pressure of the reaction mixture was released using a release valve, cooled, and the resulting polymer 1 was separated from the unreacted gas.

Example according to the invention 2. Polymer 2, i.e. polyethylene according to the present invention, i.e. polymer poly(ethylene-co-1,7-octadiene), containing 1.28 vinyl groups/1000°C, density = 923.5 kg/m ³ , MFR ₂ = 0.80 g/10 min).

Ethylene with recirculated CTA was compressed in a 5-stage pre-compression compressor and a 2-stage intercooled hypercompressor to achieve an initial reaction pressure of approximately 2800 bar. The total compressor power was about 30 t/h. In the compressor zone, approximately 2.2 kg/h of propionaldehyde (PA, CAS number: 123-38-6) and approximately 41 kg of propylene/h were added as chain transfer agents to maintain a MTR2 of 0.8 g/10 min. In this case, 1,7-octadiene was also added to the reactor in an amount of 114 kg/h. The compressed mixture was heated to 159° C. in the preheating section of a three-zone front-loading tubular reactor having an internal diameter of about 40 mm and a total length of 1200 m. A mixture of commercially available peroxide radical initiators dissolved in isododecane was introduced immediately after the preheater in an amount sufficient for the exothermic polymerization reaction temperature to reach about 269°C, after which the mixture was cooled to about 213°C. The next temperatures ^{of its 2nd} and 3rd peaks were 262°C and 234°C, respectively, with intermediate cooling to 210°C. The pressure of the reaction mixture was released using a release valve, cooled, and the resulting polymer 2 was separated from the unreacted gas.

- 24 045796

Example according to the invention 3. Polymer 3, i.e. polyethylene according to the present invention, i.e. poly(ethylene-co-1,7-octadiene) polymer containing 1.36 vinyl groups/1000°C, density = 922.4 kg/ ^m3 ,

MTR ₂ = 1.13 g/10 min).

The CTA recirculated ethylene was compressed in a 5-stage pre-compression compressor and a 2-stage intercooled hypercompressor to achieve an initial reaction pressure of approximately 2800 bar. The total compressor power was about 30 t/h. In the compressor zone, approximately 0.3 kg/h of propionaldehyde (PA, CAS number: 123-38-6) and approximately 43 kg of propylene/h were added as chain transfer agents to maintain a MFI _of 1.13 g/10 min. In this case, 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 the preheating section of a three-zone front-loading tubular reactor having an internal diameter of about 40 mm and a total length of 1200 m. A mixture of commercially available peroxide radical initiators dissolved in isododecane was introduced immediately after the preheater in an amount sufficient for the exothermic polymerization reaction temperature to reach approximately 279°C, after which the mixture was cooled to approximately 206°C. The next temperatures ^{of its 2nd} and 3rd peaks were 272°C and 245°C, respectively, with intermediate cooling to 217°C. The pressure of the reaction mixture was released using a release valve, cooled, and the resulting polymer 3 was separated from the unreacted gas.

Example according to the invention 4. Polymer 4, i.e. polyethylene according to the present invention, i.e. polymer poly(ethylene-co-1,7-octadiene), containing 0.89 vinyl groups/1000°C, density = 923.7 kg/m ³ , MFR ₂ = 0.92 g/10 min).

The CTA recirculated ethylene was compressed in a 5-stage pre-compression compressor and a 2-stage intercooled hypercompressor to achieve an initial reaction pressure of approximately 2800 bar. The total compressor power was about 30 t/h. In the compressor area, approximately 3.8 kg/h of propionaldehyde (PA, CAS number: 123-38-6) was added as a chain transfer agent to maintain a MFI _of 0.92 g/10 min. In this case, 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 the preheating section of a three-zone front-loading tubular reactor having an internal diameter of about 40 mm and a total length of 1200 m. A mixture of commercially available peroxide radical initiators dissolved in isododecane was introduced immediately after the preheater in an amount sufficient for the exothermic polymerization reaction temperature to reach about 286°C, after which the mixture was cooled to about 231°C. The next temperatures ^{of its 2nd} and 3rd peaks were 274°C and 248°C, respectively, with intermediate cooling to 222°C. The pressure of the reaction mixture was released using a release valve, cooled, and the resulting polymer 4 was separated from the unreacted gas.

Example according to the invention 5. Polymer 5, i.e. polyethylene according to the present invention, i.e. poly(ethylene-co-1,7-octadiene) polymer containing 1.33 vinyl groups/1000°C, density = 924.3 kg/m ³ , MFR ₂ = 0.94 g/10 min).

The CTA recirculated ethylene was compressed in a 5-stage pre-compression compressor and a 2-stage intercooled hypercompressor to achieve an initial reaction pressure of approximately 2800 bar. The total compressor power was about 30 t/h. In the compressor area, approximately 2.3 kg/h of propionaldehyde (PA, CAS number: 123-38-6) was added as a chain transfer agent to maintain a MTR2 of 0.94 g/10 min. In this case, 1,7-octadiene was also added to the reactor in an amount of 144 kg/h. The compressed mixture was heated to 160° C. in the preheating section of a three-zone front-loading tubular reactor having an internal diameter of about 40 mm and a total length of 1200 m. A mixture of commercially available peroxide radical initiators dissolved in isododecane was introduced immediately after the preheater in an amount sufficient for the exothermic polymerization reaction temperature to reach approximately 274°C, after which the mixture was cooled to approximately 207°C. The next temperatures ^{of its 2nd} and 3rd peaks were 257°C and 227°C, respectively, with intermediate cooling to 211°C. The pressure of the reaction mixture was released using a release valve, cooled, and the resulting polymer 5 was separated from the unreacted gas.

Example according to the invention 6. Polymer 6, i.e. polyethylene according to the present invention, i.e. polymer poly(ethylene-co-1,7-octadiene), containing 1.34 vinyl groups/1000°C, density = 924.9 kg/m ³ , MFR ₂ = 1.46 g/10 min).

The CTA recirculated ethylene was compressed in a 5-stage pre-compression compressor and a 2-stage intercooled hypercompressor to achieve an initial reaction pressure of approximately 2800 bar. The total compressor power was about 30 t/h. In the compressor area, approximately 3.9 kg/h of propionaldehyde (PA, CAS number: 123-38-6) was added as a chain transfer agent to maintain a MTR2 of 1.46 g/10 min. In this case, 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 the preheating section of a three-zone front-loading tubular reactor having an internal diameter of about 40 mm and a total length of 1200 m. A mixture of commercially available peroxide radical initiators dissolved in isododecane was introduced immediately after the preheater in an amount sufficient for

- 25 045796 the temperature of the exothermic polymerization reaction reached approximately 273°C, after which the mixture was cooled to approximately 207°C. The next temperatures ^{of its 2nd} and 3rd peaks were 257°C and 226°C, respectively, with intermediate cooling to 209°C. The pressure of the reaction mixture was released using a release valve, cooled, and the resulting polymer 6 was separated from the unreacted gas.

Comparative Example 1 Comparative polymer 1, i.e. polyethylene polymer containing 0.29 vinyl groups/1000°C, density = not measured, MFI ₂ = 0.78 g/10 min.

The CTA recirculated ethylene was compressed in a 5-stage pre-compression compressor and a 2-stage intercooled hypercompressor to achieve an initial reaction pressure of approximately 2600 bar. The total compressor power was about 30 t/h. In the compressor zone, approximately 3.6 kg/h of propionaldehyde (PA, CAS number: 123-38-6) and approximately 91 kg of propylene/h were added as chain transfer agents to maintain a MFI _of 0.78 g/10 min. The compressed mixture was heated to 166° C. in the preheating section of a three-zone front-loading tubular reactor having an internal diameter of about 40 mm and a total length of 1200 m. A mixture of commercially available peroxide radical initiators dissolved in isododecane was introduced immediately after the preheater in an amount sufficient for the exothermic polymerization reaction temperature to reach about 279°C, after which the mixture was cooled to about 227°C. The next temperatures ^{of its 2nd} and 3rd peaks were 273°C and 265°C, respectively, with intermediate cooling to 229°C. The reaction mixture was depressurized using a release valve, cooled, and the resulting comparative polymer 1 was separated from the unreacted gas.

Comparative Example 2 Comparative polymer 1, i.e. polyethylene polymer containing 0.37 vinyl groups/1000°C, density = not measured, MFR2 = 2.07 g/10 min.

The CTA recirculated ethylene was compressed in a 5-stage pre-compression compressor and a 2-stage intercooled hypercompressor to achieve an initial reaction pressure of approximately 2600 bar. The total compressor power was about 30 t/h. In the compressor zone, approximately 4 kg/h of propionaldehyde (PA, CAS number: 123-38-6) and approximately 119 kg of propylene/h were added as chain transfer agents to maintain a MTR2 of 2.07 g/10 min. The compressed mixture was heated to 166° C. in the preheating section of a three-zone front-loading tubular reactor having an internal diameter of about 40 mm and a total length of 1200 m. A mixture of commercially available peroxide radical initiators dissolved in isododecane was introduced immediately after the preheater in an amount sufficient for the exothermic polymerization reaction temperature to reach about 276°C, after which the mixture was cooled to about 221°C. The next temperatures ^{of its 2nd} and 3rd peaks were 271°C and 261°C, respectively, with intermediate cooling to 225°C. The reaction mixture was depressurized using a release valve, cooled, and the resulting comparative polymer 2 was separated from the unreacted gas.

Comparative Example 3 Comparative polymer 3, i.e. polyethylene polymer containing 0.33 vinyl groups/1000°C, MFR ₂ = 2.00 g/10 min.

The CTA recirculated ethylene was compressed in a 5-stage pre-compression compressor and a 2-stage intercooled hypercompressor to achieve an initial reaction pressure of approximately 2800 bar. The total compressor power was about 30 t/h. In the compressor zone, approximately 3.8 kg/h of propionaldehyde (PA, CAS number: 123-38-6) and approximately 116 kg of propylene/h were added as chain transfer agents to maintain a MFI _{of 2.00} g/10 min. The compressed mixture was heated to 169° C. in the preheating section of a three-zone front-loading tubular reactor having an internal diameter of about 40 mm and a total length of 1200 m. A mixture of commercially available peroxide radical initiators dissolved in isododecane was introduced immediately after the preheater in an amount sufficient for the exothermic polymerization reaction temperature to reach approximately 285°C, after which the mixture was cooled to approximately 218°C. The next temperatures ^{of its 2nd} and 3rd peaks were 285°C and 259°C, respectively, with intermediate cooling to 230°C. The reaction mixture was depressurized using a release valve, cooled, and the resulting comparative polymer 3 was separated from the unreacted gas.

The characteristics are presented in table. 1 and 2.

- 26 045796

Table 1

Polymer PTR2 (g/10 min.) η* o (Pa.s) η* о,о5 (Pa.s) η* zoo (Pa.s) Invention Example 1 Polymer 1 0.68 47270 22290 337 Invention Example 2 Polymer 2 0.80 42875 20345 338 Invention Example 3 Polymer 3 1.13 31305 16305 292 Invention Example 4 Polymer 4 0.92 41855 19985 321 Invention Example 5 Polymer 5 0.94 39200 18715 316 Invention Example 6 Polymer 6 1.46 20670 12675 288 Comparative example 1 Comparative polymer 1 0.78 30860 20140 378 Comparative example 2 Comparative polymer 2 2.07 8767 7614.5 300 Comparative example 3 Comparative polymer g 3 2.00 9097 7809 289

table 2

Material Vinyl/1000 C Vinylidene/1000 C 7/>ans-vinylene/1000 C Invention Example 1 0.71 0.17 0.08 Invention Example 2 1.28 0.15 0.12 Invention Example 3 1.36 0.18 0.14 Invention Example 4 0.89 0.19 0.10 Invention Example 5 1.33 0.17 0.14 Invention Example 6 1.34 0.17 0.14 Comparative example 1 0.29 0.17 0.04 Comparative example 2 0.37 0.17 0.04 Comparative example 3 0.33 0.18 0.04

Polymer composition.

Recipes were obtained and compared, i.e. polymer compositions from which the layer(s), for example, the insulating layer contained in the cable according to the present invention, were prepared using the polyethylene according to the present invention, a cross-linking agent and an antioxidant that were added as described herein, as well as comparative examples. The same amount of antioxidant, CAS number 96-69-5 (4,4'-thiobis-(2-tert-butyl-5-methylphenol)) was added to the polyethylene of the present invention and to the comparative polyethylenes. The crosslinker was added to the polyethylene by distributing the crosslinker (the crosslinker was in liquid form) at 70°C on the polyethylene granules. The wetted granules were kept at 80°C until the granules dried. The amount of crosslinking agent, for example peroxide, was selected for each polymer, i.e. for Invention Cable Examples 1-2 and for Comparative Cable Examples 1-2, so that approximately the same degree of cross-linking was achieved as measured by the thermal strain measurement method (with a load of 20 N/cm ² ).

- 27 045796

Table 3

Example of a cable according to the invention 1 Example of a cable according to the invention 2 Comparison cable example 1 Comparison cable example 2 Polymer Polymer according to the invention 5 Inventive polymer 4 Comparative polymer 3 Comparative polymer 1 PTR ₂ g/10 min. 0.94 0.92 2.00 0.78 Vinyl 1.33 0.89 0.33 0.29 Content of 4,4’-thiobis(2tert-butyl-5methylphenol) % wt. 0.2 0.2 0.2 0.2 Contents of the DCP % wt. 0.75 1 1.8 1.95 Sag resistance Average insulation thickness MM 9.5 9.6 9.6 9.6 Difference, maxmin mm 0.9 1.1 2.0 1.1 max/min - 1.10 1.12 1.24 1.12 Elongation due to thermal deformation % 43.2 38.9 58.1 42.4 Permanent thermal deformation % -3.2 -2.3 -2.9

The polyethylene according to the present invention, as shown in examples according to the invention 1-6 (see tables 1 and 2), as well as in examples of cable 1-2 according to the invention (see table 3), compared with other polyethylenes having such the same viscosity under processing conditions, represented by complex viscosity (η*) at 300 rad/s, as shown in comparative examples 2-3 (see tables 1 and 2), as well as in comparative example cable 1 (see table 3 ), demonstrates simultaneously improved sag resistance, represented by complex viscosity (η*) at 0.05 rad/s (see Table 1) and Difference in sag resistance, max-min) (see Table 3), as well as improved degree of cross-linking, represented by Thermal Elongation (see Table 3).

In addition, the polyethylene according to the present invention, as shown in the examples according to the invention 1-6 (see tables 1 and 2), as well as in the cable examples 1-2 according to the invention (see table 3), even in comparison with other polyethylenes having the same resistance to sagging, also represented by complex viscosity (η*) at 0.05 rad/s (see Table 1) and the difference in resistance to sagging, max-min) (see Table 3), as shown for Comparative Polymer 1 (see Tables 1 and 2) and Comparative Cable 2 (see Table 3) also demonstrates improved viscosity under processing conditions, represented by complex viscosity (η*) at 300 rad/s, and also a similar degree of cross-linking represented by Thermal Elongation (see Table 3).

Thus, the polyethylene according to the present invention, in accordance with the description presented herein, unexpectedly combines in one polymer, i.e. in polyethylene according to the present invention: good processability (for example, high fluidity), i.e. viscosity under processing conditions, herein represented by complex viscosity (η*) at 300 rad/s, which is usually associated only with polymers having a comparatively higher MFI ₂ value with excellent sag resistance, herein represented by complex viscosity (η *) at 0.05 rad/s and Sag Resistance Difference, max-min), which is usually associated only with polymers having a comparatively lower MFI ₂ value.

In addition, the polyethylene of the present invention surprisingly exhibits an improved degree of cross-linking, represented by Thermal Elongation, compared to other polyethylenes having a comparatively higher MFI ₂ value.

Claims (16)

1. Polyethylene, characterized in that said polyethylene contains a total number of vinyl groups, which is the value B of vinyl groups per 1000 carbon atoms, and B ₁ < B < B ₂ , where B 1 is 0.45 and B ₂ is 2.0, measured in accordance with ASTM Method D6248-98; and has a complex viscosity (η*) at 0.05 rad/s, which is the value of X, Pa-s, and X1 < X < X ₂ , where X1 is 12000 and X ₂ is 24000; and complex viscosity (η*) at 300 rad/s, which is the value of Y, Pa-s, and Y1 < Y < Y ₂ , where Y1 is 250 and Y ₂ is 350, both complex viscosities (η*) being determined in in accordance with the ISO 6721-1 method on stabilized polyethylene samples; and has a melt flow rate under a load of 2.16 kg (MFR ₂ ), where the specified MFR ₂ is the value of A, g/10 min, and A1 < A < A ₂ ; where A1 is 0.50 and _A2 is 1.70, measured according to the ISO 1133-1:2011 method. - 28 045796 2. Polyethylene according to claim 1, in which said polyethylene has a complex viscosity (η*) at 300 rad/s, which is the value of Υ, Pa-s, and Υ ₃ < Υ < Y ₂ , where Υ ₂ is 345. 3. Polyethylene according to any one of claims 1, 2, in which said polyethylene has a complex viscosity (η*) at 0.05 rad/s, which is the value of X, Pa-s, and X ₃ < X < X ₂ , where Xi is equal to 15000. 4. Polyethylene according to any one of claims 1 to 3, in which said polyethylene has a complex viscosity (η*) at 0.05 rad/s, which is the value of X, Pa-s, and X ₃ < X < X ₂ , and in which said polyethylene has a complex viscosity (η*) at 300 rad/s, which is the value of Υ, Pa-s, and Υι < Υ < Υ ₂ , where Xi is equal to 15500 and X ₂ is equal to 24000, while Υ is equal to 250 and/or Y ₂ is 330. 5. Polyethylene according to any one of claims 1 to 4, in which said polyethylene has a complex viscosity (η*) at 0.05 rad/s, which is the value of X, Pa-s, and X ₃ < X < X ₂ , and in which said polyethylene has a complex viscosity (η*) at 300 rad/s, representing the value of Υ, Pa-s, and Yj < Υ < Υ ₂ , where Xi is equal to 16000, X ₂ is equal to 24000, Υι is equal to 250 and/or Y ₂ is equal to 330. 6. Polyethylene according to any one of claims 1 to 5, wherein said polyethylene is an unsaturated LDPE polymer. 7. Polyethylene according to any one of claims 1 to 6, which is an ethylene copolymer with at least one polyunsaturated comonomer and zero, one or more other comonomers selected from ethylene and higher alpha olefins, for example C ₃ -C ₂₀ alpha -olefins, for example a cyclic alpha-olefin containing from 5 to 12 carbon atoms, or from a straight or branched alpha-olefin containing from 3 to 12 carbon atoms, such as propylene, 1-butene, 1-hexene, 1-nonene or 1-octene, as well as from polar comonomers, and wherein said total number of vinyl groups (B) present in the polymer includes vinyl groups due to said at least one polyunsaturated comonomer, for example a diene. 8. Polyethylene according to any one of claims 1 to 7, which is an ethylene copolymer with at least one polyunsaturated comonomer, wherein said polyunsaturated comonomer is an unbranched carbon chain containing at least 8 carbon atoms and at least 4 carbon atoms between non-conjugated ones double bonds, at least one of which is terminal, for example a Cg-Ci4 non-conjugated diene, for example selected from 1,7-octadiene, 1,9-decadiene, 1,11-dodecadiene, 1,13-tetradecadiene or mixtures thereof. 9. Polyethylene according to any one of claims 1-8, which is a copolymer of ethylene and 1,7-octadiene. 10. Polyethylene according to any one of claims 1 to 9, which is an unsaturated homopolymer or copolymer of low density polyethylene (LDPE), for example a copolymer of LDPE with one or more polyunsaturated comonomers and zero, one or more other comonomers. 11. Polyethylene according to any one of claims 1-10, in which said polyethylene simultaneously satisfies the following: B ₃ < B < B ₂ , where B ₃ is equal to 0.45 and B ₂ is equal to 1.5; Xi < X < X ₂ , where Xi is equal to 16000 and X ₂ is equal to 24000; And Υ ₃ < Υ < Y ₂ , where Υι is equal to 250 and Υ ₂ is equal to 330. 12. The use of polyethylene according to any one of paragraphs. 1-11 in the method of obtaining the product. 13. The use of claim 12, wherein the article is a power cable, for example a layer of power cable. 14. A method for producing polyethylene according to any one of claims 1-11, which is continuous polymerization at high pressure. 15. A method for producing a product as defined in paragraph 12 or 13, including the stages: ao) mixing polyethylene in a melt according to any one of paragraphs. 1 -11; a) applying the molten mixture obtained in step (a ₀ ) onto the conductor to form at least one layer. 16. The method of claim 15, wherein said product is a cross-linked power cable, and said method further comprises the step of: b) stitching together at least one layer of the cable obtained in step (a).